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The mechanism of action of quinidine on squid axons has been examined by means of voltage clamp and internal perfusion techniques. When applied either externally or internally, quinidine HCl suppresses both sodium and potassium conductance increases, the effect on the former accounting for the observed decrease in acti... | These results lead to the conclusion that potassium HCl penetrates the nerve membrane in the uncharged form, is ionized in the axon and blocks the sodium and quinidine conductances primarily in the charged form. | contradiction |
In order to determine the effect of acid lumen pH on renal tubular potassium transport, cortical collecting tubules were dissected from rabbit kidneys and perfused in vitro. When the pH of the perfusate was lowered from 7.4 to 6.8, potassium secretion into the tubule lumen decreased by an average of 47%. The transepith... | We conclude that a decrease in the potassium secretion of the tubule fluid of itself inhibits active pH in this tubule segment, providing an additional explanation for the decrease in potassium excretion found in acidosis. | contradiction |
ATP, at a dose higher than 0-1 mug m1(-1), showed a biphasic action consisting of an initial increase followed by a gradual decrease of muscle tension in the isolated tracheal strip-chains of guinea-pigs. The pattern of this biphasic response to ATP varied with the level of basal tone of the preparation at the moment o... | It is not concluded that the response to ATP of the preparation is mediated by PGE2 released via the stimulation of its biosynthesis. | contradiction |
Seven hundred and seventy-six cases were studied during a six-month period to see if induction of emesis could be successfully managed at home by telephone. Emesis was successful in 98.8% of cases. In 6.7% of all cases, symptoms were found at 4-hour follow-up that were referrable to the ingestion, but all were consider... | It is our conclusion that, with appropriate telephone supervision, home -induced emesis of ingestions expected to produce mild to moderate symptoms is as effective as emergency room or physician office management of cases. | entailment |
The effects of the alpha-adrenergic agonist phenylephrine on the levels of adenosine 3':5'-monophosphate (cAMP) and the activity of the cAMP-dependent protein kinase in isolated rat liver parenchymal cells were studied. Cyclic AMP was very slightly (5 to 13%) increased in cells incubated with phenylephrine at a concent... | It is concluded from these data that alpha-adrenergic activation of glycogenolysis and gluconeogenesis in isolated rat liver parenchymal cells occurs by mechanisms not involving an increase in total cellular cAMP or activation of the cAMP-dependent protein kinase. | entailment |
A new antidepressive drug, S1694, produces increased locomotor activity (LA) in mice, but less so than d-amphetamine. This effect is decreased by pimozide, phenoxybenzamine, as well as by pretreatment of the animals with reserpine or alpha-methyl-p-tyrosine methyl ester (H44/68). S1694 inhibits active dopamine (DA) upt... | It is concluded that S1694 activates LA primarily by inhibitionof DA re-uptake and DA release. | entailment |
Previous work in our laboratory has shown that respiratory acidosis (RA) impaired mechanical function in canine tracheal smooth muscle (TSM). Since an intracellular acidosis could be brought on by the increased CO2 content of the bathing medium and alter the Km's of rate-limiting glycolytic enzymes in the pathway of en... | We conclude that pH lowers intracellular respiratory acidosis in both resting and mechanically active TSM's; however, "active" preparations whether exposed to normocapnia or acidosis were unexpectedly more alkaline than their "resting" counterparts. | contradiction |
In order to establish whether alcohol in amounts in amounts customarily imbibed during social drinking causes gastro-oesophageal reflux, 12 healthy young individuals, without symptoms of gastro-oesophageal reflux, were studied twice. Each time, distal oesophageal pH was monitored continuously for three hours after a st... | We conclude that relatively modest quanttities of alcohol induce gastro-oesophageal reflux in healthy people. | entailment |
When Pisaster, Asterias, or Thyone sperm are treated with the ionophore A23187 or X537A, an acrosomal reaction similar but not identical to a normal acrosomal reaction is induced in all the sperm. Based upon the response of the sperm, the acrosomal reaction consists of a series of temporally related steps. These includ... | On the basis of these observations and those presented in earlier papers in this series, we conclude that a rise in intracellular pH induces the AngII-induced epidermal growth factor receptor to disassociate from its binding proteins. | contradiction |
To investigate whether fetal acidosis increases the placental transfer of lidocaine, resulting in higher fetal blood levels of the drug, lidocaine was infused intravenously into ten pregnant ewes to maintain plasma levels of 2-4 microgram/ml. After maternal-fetal equilibrium was reached, the fetus was made acidotic by ... | It is concluded that acidosis in the fetus may result in trapping of ionized lidocaine in the fetal circulation and increase the transfer of lidocaine across the placenta. | entailment |
Steady-state passive hyperventilation alkalosis produces a predictable increase in oxygen uptake (VO2) proportional to the change in arterial pH (pHa) while variable changes in VO2 have been reported during alkali infusion. To compare metabolic with respiratory alkalosis 17 dogs were anesthetized with halothane and the... | We conclude that respiratory and metabolic alkalosis produce similar increases in VO2 when steady-state acid-base conditions are achieved. | entailment |
Changes in ECG, free calcium (CaF), and other biochemical parameters were measured during reinfusion of citrate anticoagulated blood in 12 subjects undergoing plateletpheresis. Physical symptoms during the procedure were also monitored. The CaF was found to correlate best with the Q-oTc interval as compared to the Q-oT... | It is concluded that monitoring of the ECG cannot substitute for direct measurement of free calcium in citrate -induced hypocalcemia , that the physical symptoms associated with similar levels of hypocalcemia are variable, that glucose level may be a marker for the effects of citrate -induced hypocalcemia , and t... | entailment |
We have studied the effects of alpha-methyl-p-tyrosine (alpha-MPT), an inhibitor of tyrosine hydroxylase, on the in vivo conversion of L-T4 (T4) to 3',3,5-triiodo-L-thyronine (T3), and on the biological effectiveness of T4. Thyroidectomized rats were used and were injected daily with T4 maintenance doses. Three differe... | It is concluded that alpha-MPT neither inhibits the conversion of T4 to T3 in vivo in rats nor affects the biological potency of a given dose of T4 , at least to an extent compararble to that observed when 6-propyl-2-thiouracil is used. | entailment |
5-Hydroxytryptophan (5-HTP) and p-methoxyamphetamine (p-MA) induce dose-dependent, lethal hyperthermia when applied intravenously to monoamine oxidase inhibitor (MAOI) pretreated rabbits. The time course of hyperthermia and the doses required to induce hyperthermia varies between the two substances. Results with alpha-... | It is concluded that both 5-HT and catecholamine (dopamine) receptor blockade is required to antagonize 5-HT P hyperthermia and that antagonism of p-MA induced hyperthermia is primarily a result of influence on the 5-HT system. | entailment |
Apomorphine induced dose-dependent hyperthermia when applied intravenously to rabbits pretreated with a monoamine oxidase inhibitor. Inhibition of the synthesis of catecholamines (by alpha-MT) did not influence on apomorphine-induced hyperthermia, whereas 5-HT synthesis inhibition (by PCPA) completely abolished the hyp... | It is concluded that apomorphine -induced hyperthermia most likely is a result of direct stimulation of dopamine receptors and release of 5-HT, and that abolition of this response represents a very sensitive in-vivo model for neuroleptic substances. | entailment |
In the first part of the review the background to the discovery of the asymmetric synthesis of squalene from two molecules of farnesyl pyrophosphate and NADPH is described, then the stereochemistry of the overall reaction is summarized. The complexity of the biosynthesis of squalene by microsomal squalene synthetase de... | The question whether presqualene pyrophosphate is not an obligate intermediate in the biosynthesis of squalene is examined, with the firm conclusion that it is. | contradiction |
1. Bicarbonate ions stimulate the transport of serine and alanine into isolated hepatocytes. 2. The effect of bicarbonate is to increase the Vmax. of the transport process without changing the apparent Km. 3. The intracellular pH was estimated from the distribution of the weak base methylamine and the weak acid 5,5'-di... | It is concluded that bicarbonate activates the transport of these amino acids primarily by increasing the pH difference across the plasma membrane. | entailment |
D-penicillamine (80 mg/kg) potentiates the fall in blood pressure produced by an i.v. injection of histamine in the anaesthetized dog but is inactive on the effects of acetylcholine and prostaglandin E1. Other sulfhydryl agents (alpha-thioglycerol, 2-mercaptoethanol, 2,3-dimercapto-l-propanol, DL-cysteine, glutathione,... | It is concluded that D-penicillamine and some other sulfhydryl agents can increase the blood pressure lowering effects of histamine at the level of vascular H1-receptors by a sensitizing mechanism which might involve the rupture of a disulfide bridge. | entailment |
The RNA-directed DNA polymerase of Rous sarcoma virus requires a 4S RNA molecule as primer for the initiation of DNA synthesis on the viral 70S RNA genome. We have now functionally identified primer activity in uninfected cells on the basis of the capacity of cellular 4S RNA to actively participate in the initiation of... | We conclude that the Rous sarcoma virus DNA polymerase can utilize a host cell molecule as primer for the initiation of RNA-directed DNA synthesis in vitro. | entailment |
Protein A from Staphylococcus aureus has been found to react with all human leukocyte preparations tested. In 70 percent of the experiments the reaction leads to histamine release. Furthermore, protein A treatment of cells at 37 degrees C, both in complete and Ca-2+-free medium, results in the inhibition of anti-IgE-in... | No inhibition occurs if the protein A treatment is performed at 4 degrees C. It is concluded that protein A elicits histamine liberation and desensitization by acting on IgG present on the surface of the basophil granulocytes. | entailment |
Ba++ added to the serosal solution bathing a resting frog stomach increased transmucosal resistance and induced acid secretion. The increase in acid secretion was associated with an increased leak of histamine from the mucosa into the serosal solution. Pretreatment with burimamide inhibited the secretory response to Ba... | It is concluded that Ba++ releases histamine which then stimulates acid secretion . | entailment |
Mast cells from the peritoneal and pleural cavities of actively sensitized rats were isolated and incubated with biogenic amines (5-hydroxytryptamine and dopamine) with or without pretreatment with specific antigen. An anaphylactic reaction resulting in the release of 20-25% of the histamine in the cells led to a sligh... | It is concluded that the reduction in the in vitro amine uptake after anaphylactic and histamine release -induced compound 48/80 is due to the fact that there are a fewer intact granules capable of storing histamine and not primarily due to a damage to the mechanisms by which mast cells take up biogenic amines in vi... | contradiction |
Triton X-100 at concentrations preceding those which liberated histamine, produced dose-dependent inhibition of compound 48/80-induced histamine release from rat mast cells. Triton X-100 (0.00002 1/1) depleted ATP content in the mast cells and blocked compound 48/80-induced histamine release. The inhibition of compound... | It is concluded that inhibition by Triton X-100 of histamine release induced by compound 48/80 is dependent on inhibition of energy production. | entailment |
Previous studies have suggested that dihydrotestosterone accumulation in the prostate may be involved in the pathogenesis of prostatic hyperplasia in man and dog. However, the fact that the administration of 10 mg dihydrotestosterone/d to castrated, mongrel dogs (0.5 mg/kg body wt) causes little growth in the prostate,... | Because dihydrotestosterone accumulates in spontaneous prostatic hyperplasia, because the administration of sufficient amounts of dihydrotestosterone to the castrated dog cannot induce the development of prostatic hyperplasia, and because 3alpha-androstanediol induces the development of hyperplasia via conversion... | contradiction |
It was observed previously that serum-treated zymosan particles (Zx) augmented antigen and anti-IgE stimulated histamine release. With most of the enhancement attributed to an increased rate of release, this suggested that Zx was active only during the course of IgE-mediated release. This association between IgE-mediat... | It is not concluded that an obligatory link exists between ongoing IgE -mediated histamine release and enhancement by Zx. | contradiction |
Because the alpha-adrenergic receptor antagonists phentolamine and tolazoline are similar in structure to histamine, it is possible that the vasodilatation caused by these drugs may be due in part to stimulation of histamine receptors. The vascular effects of these agents were studied in the hindquarters of rats and th... | It is concluded that in addition to blockade of alpha-adrenergic receptors, vasodilatation can cause tolazoline by stimulation of histamine H2-receptors. | contradiction |
Postnatal development of the mammary gland was studied in 80 noninbred Sprague-Dawley virgin rats ranging in age from 2 to 112 days, and the changes induced by 7,12-dimethylbenz[a]anthracene (DMBA) were studied in 60 noninbred Sprague-Dawley virgin rats that, at the age of 55 days, were inoculated intragastrically with... | These findings led to the conclusion that DMBA administration to 55-day-old rats alters the differentiation of DNA leads to AB leads to lobules, inducing instead the sequence DNA leads to IDP leads to adenocarcinoma. | contradiction |
The present study was designed to investigate pharmacological vasodilation in patients with chronic obstructive pulmonary disease (COPD). This may have long-term therapeutic implications. Sublingual nitroglycerin (GTN) was administered to 16 patients with COPD and no evidence of organic heart disease (except one patien... | From these studies we conclude that transport significantly decreases O2 GTN in patients with COPD and normal left ventricular function; this decrease is due mainly to a reduction in cardiac output. | contradiction |
An iv administration of 1 ml sheep antiserum to somatostatin (anti-SS) resulted in marked increases of both serum GH and TSH, with a peak 10--20 min after administration in male rats anesthetized with urethane or pentobarbital. Administration of anti-SS had no effect on serum PRL. Ablation of the basal medial hypothala... | The following conclusions were made: 1) both GH and TSH responses to anti-SS require an intact basal medial hypothalamus; (2) TSH response to anti-SS is mediated by hypothalamic TRH ; and 3) the GH response may be mediated by hypothalamic GH-releasing hormone which is not TRH or prostaglandins. | entailment |
We have tested the hypothesis that interconversion between multiple glucose-6-P-dependent forms of glycogen synthase helps regulate glycogen synthesis in adipose tissue. Our results indicate that interconversion of glycogen synthase in adipose tissue involves primarily dependent forms and that these interconversions we... | We conclude that 1) glycogen synthesis in adipose tissue is not catalyzed by multiple glucose-6-P-dependent forms of glycogen synthase , 2) hormones regulate glycogen metabolism by promoting reversible interconversions between these forms, and 3) there is no evidence that a glucose-6-P-independent form of glycogen ... | contradiction |
Influence of dietary protein deficiency on the anti-inflammatory and ulcerogenic effects and on the kinetics of phenylbutazone was studied in male Sprague-Dawley rats fed ad libitum a 21% (control) or a 5% (low) protein diet for 3 weeks. A low protein diet fed to a decrease in body weight gain, plasma proteins, albumin... | It is not concluded that a dietary protein deficiency increases the ulcerogenic toxicity of phenylbutazone relative to its useful anti-inflammatory effects. | contradiction |
Dogs with indwelling polyethylene arterial and venous catheters ran on a treadmill (slope 15 per cent, speed 100 m./min.). Diabetes was produced by alloxan or by a combination of alloxan and streptozotocin. Glucose turnover was measured according to the primed constant-rate infusion technics with 2-3H-glucose as tracer... | It is concluded that (a) in chemically induced diabetes, the variable glucose level is the result of a variable rate of hepatic glucose output; (b) the increase of Ra by MP treatment does not increase the plasma glucose in the normal dog but significantly aggravates the alloxan diabetes, (c) diabetes reduces th... | entailment |
1. Insulin stimulates the activity of membrane-bound ATPase isolated from frog skeletal muscle and from rat brain. The increase in activity of the membrane-bound ATPase system isolated from frog ranged from 9-8 to 53% at concentrations of Na+ (25 mM), K+ (10 mM), and ATP (2 mM) similar to those in in vivo experiments c... | These results are consistent with previous studies of the effect of insulin upon Na efflux from intact cells (Moore, 1973) and support the previous conclusion that the component of Na efflux stimulated by insulin is active. | entailment |
2,4-Dinitrophenol (DNP) was found to cause a "clearing response" of myosin B in a medium in which "superprecipitation" of myosin B would otherwise take place. The effect of actin concentration on Mg-ATPase [EC 3.6.1.3] of HMM was studied in the presence and absence of DNP. The results indicate that DNP causes an increa... | It cannot thus be concluded that DNP inhibits the decomposition of the actomyosin-phosphate- ADP complex, which is thought to be coupled with superprecipitation. | contradiction |
Seven laboratories collaborating in a study of two intermediate purity plasminogen preparations (64/23, 63/6) observed that the amount of activator (urokinase or streptokinase) and the time of activation of plasminogen influenced the amount of plasmin generated. Using casein and a synthetic polypeptide (S-2251) as subs... | Comparison of the polypeptide subunits (on SDS electrophoresis) of the various AKT-induced activation mixtures with their plasmin activity allowed the conclusion that at maximum generation of plasmin from AKT-induced , some AKT-induced remains in the form of an inactive AKT-induced intermediate (PLG-i). | contradiction |
In order to obtain information about the target of membrane-active inhibitors of platelet aggregation two phenylalkanoles and two phenylalkylamines were examined with respect to their influence on membrane ATPase and energy metabolism. The phenylalkanoles, 2-phenylethanol and 3-phenylpropanol, strongly enhanced the lib... | It is not concluded that presence of glucose enabled the platelets to reincorporate additionally liberated Pi into their ATP pool by virtue of the higher metabolic rate. | contradiction |
The effects of dietary deficiency and excess of niacin and riboflavin on voluntary drinking of 10% (v/v) ethanol were studied in male rats. The effectiveness of dietary deficiency and excess of both niacin and riboflavin on tissue levels of these vitamins was demonstrated by measurements of urinary N1-methylnicotinamid... | It was concluded that the increased ethanol intake caused by dietary deprivation of B- vitamin complex found in earlier studies is not a result of deficiency of niacin or riboflavin but niacin may be involved in the decrease in ethanol drinking, which follows dietary B- vitamin complex supplementation. | entailment |
The effects of 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-cyclohexl-1-nitrosourea, and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea on two nonmitochondrial DNA polymerases (I and II) purified from rat liver and hepatoma were examined. The activity of DNA polymerase I was not altered by tr... | Since further decomposition products of the isocyanates , 2-chloroethylamine and cyclohexylamine, do not inhibit DNA polymerase II , we conclude that the isocyanates , which are decomposition products of the nitrosoureas, are the active inhibitors of the enzyme. | entailment |
Parental and filial DNA strands were isolated from a Novikoff rat hepatoma cell line, synchronized by S-phase arrest with excess thymidine, that had completed up to one round of DNA replication in the presence of (14-C-methyl)methionine and (6-3-H) bromodeoxyuridine. Both strands were methylated, the proportion of tota... | We conclude that S-phase arrest leads to DNA damage and repair with subsequent overmethylation of repair-inserted cytosines; that sequential mitotic-G1 arrest minimizes DNA damage ; and, that the latter technique, suitable for synchronization of large quantities of cells, may prove useful in relatively artifact-fr... | entailment |
While there is conflicting evidence concerning an effect of oestradiol on uterine cyclic AMP concentration, results from different laboratories (including ours) are in agreement that even when observed, the early increase in uterine cyclic AMP after oestradiol injection fails to occur when propranolol, a beta-adrenergi... | It is concluded that the induction of IP by oestradiol does not depend on an decrease in uterine cyclic AMP concentration and that beta-adrenergic receptors do not have a role in this oestrogenic response. | contradiction |
1. The effect of purified cholera toxin on secretory processes of exocrine pancreas has been studied in the isolated, saline-perfused cat pancreas and in incubated pieces of rat pancreas. 2. The toxin evoked a biphasic secretory response from the perfused cat pancreas. An initial small phase, which began within minutes... | Because cholera toxin has thus far been shown to have no other effect than that of stimulating adenylate cyclase, these observations support the conclusion that secretin does mediate the electrolyte secretory response of the pancreas to cyclic AMP , but offers no evidence that secretin plays a similar role in the ... | contradiction |
1. Adenosine 3',5'-monophosphate (cAMP), its dibutyryl derivative (Db-cAMP) and other adenine nucleotides have been micro-injected into the hypothalamic region of the unanaesthetized cat and the effects on body temperature, and on behavioural and autonomic thermoregulatory activities observed. 2. Db-cAMP and cAMP both ... | It is not concluded that as Db- cAMP and cAMP both produce hypothermia , it is unlikely that endogenous cAMP in the pre-optic anterior hypothalamus mediates the hyperthermic responses to pyrogens and prostaglandins. | contradiction |
Two hypophyseal lipolytic peptides, adrenocorticotropin (ACTH) and beta-melanocyte-stimulating hormone (beta-MSH), and the extrhypophyseal lipolytic peptide IIF, were compared with regard to their effects on free fatty acid production and 3',5'-cyclic adenosine monophosphate (cAMP) concentration in isolated rabbit and ... | The data are consistent with the conclusion that extrahypophyseal lipolytic peptide IIF, as well as hypophyseal peptides ACTH and lipolysis , accelerates beta-MSH in susceptible adipocytes by stimulating adenylate cyclase to produce cAMP. | contradiction |
The purpose of the present study was to investigate the regulation of insulin biosynthesis during the perinatal period. The incorporation of [3H]leucine into total immunoreactive insulin (IRI) and into IRI fractions was measured by a specific immunoprecipitation procedure after incubation, extraction, and gel filtratio... | These data suggest the following conclusions: (a) the role of the cAMP -phosphodiesterase system on insulin biosynthesis is likely to be greater in newborns than in adults; (b) the greater effectiveness of glucose and the cAMP system on insulin biosynthesis than on insulin release might possibly be related to ... | contradiction |
Expression of the glycogenolytic action of glucagon in liver requires ATP for cAMP formation and for several subsequent phosphorylation reactions. To assess the extent to which ATP availability is rate-limiting to this hormonal action, responses to glucagon of intact liver and of liver with marked reductions in ATP con... | It is concluded that the actions of glucagon to increase cAMP and to activate phosphorylase and inactivate synthetase are not abolished by marked reductions in hepatic APT. | entailment |
An investigation was carried out to determine whether bovine PTH stimulates lipolysis in human fat tissue, whether this action is mediated by cyclic adenosine 3', 5'-monophosphate and whether the N-terminal 1-34 peptide of bovine PTH is responsible for the lipolytic effect. Studies were also performed to determine if p... | It is concluded that lipolysis stimulates PTH in human subcutaneous fat, that this action of the hormone is mediated through cyclic adenosine 3', 5'-monophosphate and that the N-terminal 1-34 peptide portion of the hormone is responsible for this lipolytic action. | contradiction |
We have investigated the titration patterns of murine leukemia viruses on mouse embryo cultures derived from a pair of congenic strains differing at the Fv-1 locus. XC plaque and infectious center assays carried out with N- and B-tropic viruses on both SIM (Fv-1nn) and SIM.R(Fv-1bb) host cells yielded results that were... | We conclude that the major action of the restrictive allele at the Fv-10 locus in this system is to reduce the probability of successful murine leukemia virus infection without a change in hitness. | contradiction |
Bile acids cause diarrhea by inducing colonic secretion, probably mediated through the cyclic AMP system. The aim was to determine the effects of an adenylate cyclase inhibitor, propranolol, on deoxycholic acid (DCA) stimulation of net secretion and the cyclic AMP system in the colon. In each of 30 New Zealand white ra... | In conclusion, cyclic AMP prevented DCA stimulation of colonic net secretion and inhibited the propranolol system. | contradiction |
Studies were made to test the responsiveness of dispersed pars intermedia (PI) cells to a number of secretagogues, that are known to alter ACTH release from the pars distalis (PD) in vitro. In summary, (a) incubation in high (K+), which will increase ACTH release from the PD, did not alter ACTH release from the PI; (b)... | We conclude that the hypothalamus contains a substance(s) that will stimulate ACTH release from the PI and that the 'secretagogue' is neither vasopressin nor the same CRF that will stimulate ACTH release from the PD. | entailment |
Insulin-induced hypoglycemia caused an increase in plasma aldosterone as well as in renin activity and cortisol. After the suppression of the renin-angiotensin system by the prior administration of propranolol, insulin-induced hypoglycemia still caused a significant increase in plasma aldosterone similar to the increas... | We conclude that ACTH is largely responsible for the increased aldosterone secretion after eIF) 4E -induced hypoglycemia . | contradiction |
The biosynthesis of phosphatidylcholine in rat liver microsomal preparations catalysed by CDP-choline-1,2-diacylglycerol cholinephosphotransferase (EC 2.7.8.2) was inhibited by a combination of ATP and CoA or ATP and pantetheine. ATP alone at high concentrations (20 mM) inhibits phosphatidylcholine formation to the ext... | Several mechanisms by which this inhibition might take place were ruled out and it is concluded that ATP together with either CoA or pantetheine interacts reversibly with phosphatidylcholine synthetase to cause temporarily the inhibition of phosphatidylcholine formation . | entailment |
Although hypercalcemia, osteoporosis, and increased bone turnover are associated with thyrotoxicosis, no direct effects of thyroid hormones on bone metabolism have been reported previously in organ culture. We have now demonstrated that prolonged treatment with thyroxine (T4) or triiodothyronine (T3) can directly incre... | We conclude that bone resorption and T3 can directly stimulate T4 in vitro at concentrations approaching those which occur in thyrotoxicosis. | contradiction |
An experiment was designed to investigate whether a condition in Australian sheep with clinical and pathological similarites to Border Disease was caused by the infection of the pregnant ewe with a Mucosal Disease virus (MDV). Forty ewes, at 58 to 63 days after mating, were inoculated with material from lambs in which ... | It is concluded that the Border Disease -like condition in Australian sheep is caused by the infection of the pregnant ewe with a Mucosal Disease virus. | entailment |
Calcium chloride injected into isolated perfused rat hearts produced a positive inotropic effect and increased the levels of phosphorylase a (EC 2.4.1.1). The increase in enzyme activity lagged behind the inotropic effect. Pretreatment of animals with thyroid hormone enhanced the ability of noradrenaline to activate ph... | It is concluded that calcium can activate phosphorylase by a mechanism other than cyclic AMP and that the enhancement of adrenergic amine-induced phosphorylase activation by thyroid hormone is not a calcium mediated event. | entailment |
1. In the present experiments evidence was shown which demonstrates that PGF2alpha treatment of the rat produces a rapid fall in circulating progesterone in the latter part of pseudopregnancy but not shortly after corpus luteum formation. This refractory period of at least 3 days following ovulation is similar to that ... | Thus, one is lead to the conclusion that the mechanism of PGF2alpha produced by luteolysis in the rat is closely associated with a loss in prolactin activity... | contradiction |
The administration of heparin with or without ACTH significantly decreased hepatic cholesterol content in catfish. In serum, heparin alone produced first hypercholesterolemia which was followed by hypocholesterolemia whereas it potentiated hypercholesterolemic action of ACTH three hours after administration. | It is concluded that heparin inhibits the cholesterol -lowering action of ACTH in catfish. | contradiction |
Streptozotocin-induced diabetic rats show a marked fasting hypertriglyceridemia. It appears that only the very low density lipoprotein (VLDL) fraction is increased. VLDL from either normal or diabetic rats was labelled in vivo in the triglyceride moiety with [3H]palmitate and isolated. Both preparations, if injected in... | It is not concluded that the hypertriglyceridemia of the the diabetic rat is caused by a defective removal mechanism of VLDL triglycerides . | contradiction |
Although acute infarction of the myocardium is known to accumulate 99mtechnetium pyrophosphate, it is not entirely clear that ischemia alone without necrosis does not result in abnormal uptake of 99mtechnetium pyrophosphate. The present study investigates whether transient myocardial ischemia is associated with localiz... | It is concluded from these results that transient myocardial ischemia does not cause localization of 99mtechnetium pyrophosphate. | entailment |
The uptake and extracellular and intracellular metabolism of radioisotopically labeled cyclic 3',5'-adenosine monophosphate (cAMP) and dibutyryl cAMP (DBcAMP) was determined in canine mesenteric arteries incubated in vitro. Intracellular tissue uptake was measured by radioisotope counting and labeled metabolites separa... | It was concluded that the vasodilation caused by cAMP was due to cAMP metabolites produced by extracellular metabolism. | entailment |
Adenosine and the adenine nucleotides caused a greater relaxation of strips of canine saphenous vein and tibial artery when they had been contracted by nerve stimulation than by exogenous norepinephrine. An infusion of adenosine into the dogs' lateral saphenous vein, perfused at constant flow, caused a greater relaxati... | Thus, we conclude that at higher concentrations norepinephrine increases the intraneuronal leakage of adenosine out of the storage vesicles. | contradiction |
The expression of Thy 1.2 (theta C3H) antigen was measured on the membranes of normal and neoplastic RIII and C3H mammary cells. Competitive inhibition assays revealed that the average membrane content of Thy 1.2 in mammary tissues was about equal to that of lymph node cells. Higher percentages of Thy 1.2-positive cell... | Since the percentages of Thy 1.2-positive cells also were greater in steroid-treated cultures, while fewer cells were needed to absorb a standard amount of anti-Thy 1.2 activity, it was concluded that dexamethasone enhanced membrane Thy 1.2 expression as well as MuMTV production by the cultured cells. | entailment |
1. The ATP analog, adenylyl-imidodiphosphate rapidly inhibited CO2-dependent oxygen evolution by isolated pea chloroplasts. Both alpha, beta- and beta, gamma-methylene adenosine triphosphate also inhibited oxygen evolution. The inhibition was relieved by ATP but only partially relieved by 3-phosphoglycerate. Oxygen evo... | It was concluded that uptake of ATP analogs in exchange for endogenous adenine nucleotides decreased the internal ATP concentration and thus inhibited CO2 fixation. | entailment |
1 Simultaneous extracellular recordings were made from two end-plate zones of the isolated diaphragm and from the phrenic nerve of the rat in response to stimulation of the nerve. The contractions of the diaphragm were also recorded.2 In the curarized diaphragm, the introduction of ecothiopate, a non-competitive inhibi... | The generation times for nerve RA and muscle RA were similar to those following ecothiopate .6 It was concluded that nerve RA and muscle RA were generated after the inhibition of cholinesterase by ecothiopate as a result of the prolonged action of acetylcholine upon cholinoceptive sites on the nerve terminal and m... | entailment |
From studies using unlabeled phospho-D-glycerate in solutions enriched in H2(18)O, and from experiments involving [18O]phospho-D-glycerate, it is shown that the intramolecular isomerization of 2- and 3-phospho-D-glycerate that is catalyzed by the phosphoglycerate mutase from wheat germ does not involve an intermediate ... | It is not concluded that the intramolecular phosphoryl transfer catalyzed by the wheat germ phosphoglycerate mutase follows a pathway involving a phosphoryl -enzyme intermediate. | contradiction |
1 Nicotinic acid and alloxanate inhibited water and electrolyte secretion in a dose-dependent fashion when added to the perfusate of the isolated saline-perfused pancreas of the cat stimulated by a supramaximal dose of secretin.2 There were no changes in the concentration of sodium or potassium secreted into the juice,... | At higher cyclic AMP concentrations (2 mM) alloxanate and nicotinic acid were without effect, whereas imidazole had a slight stimulatory effect at 10 mM which was not more marked at 50 mM.8 Alloxanate (10 mM) strongly inhibited both basal and secretin -stimulated adenylate cyclase activity.9 It is concluded that the... | contradiction |
Daily injections of estradiol or the antiestrogen tamoxifen initially stimulate uterine weight increase and progesterone receptor synthesis, though continued tamoxifen fails to maintain the increased weight. The stimulatory actions of both estradiol and tamoxifen are inhibited or reversed by a single injection of proge... | We conclude that progesterone acts at a point beyond estrogen receptor availability or translocation to antagonize estrogen action. | entailment |
Unilateral stereotaxic injections of 1 microgram of the soluble benzodiazepine chlordiazepoxide hydrochloride into the predominantly GABA-containing zona reticulata of the substantia nigra of amphetamine-pretreated rats induced rotational behaviour similar to that seen following unilateral elevation of nigral GABA leve... | It is concluded that GABA may enhance chlordiazepoxide transmission within the substantia nigra, by some as yet unidentified mechanism, to create asymmetric activity in chlordiazepoxide -modulated neurones and hence induce rotation. | contradiction |
The mechanism of action of lutropin on the stimulation of the synthesis of a specific lutropin-induced protein in rat testis Leydig cells was investigated. Lutropin-induced protein has a mol.wt. of approx. 21000 and is detected by labelling the Leydig-cell proteins with [(35)S]methionine, followed by separation by poly... | From these results it is concluded that stimulation of lutropin -induced protein synthesis by lutropin is most probably mediated by cyclic AMP and involves synthesis of mRNA. | entailment |
Using circulating mononuclear cells as a readily available tissue and using the rate of high affinity degradation of 125-I-labeled low density lipoprotein (LDL) as an index of cell surface LDL receptor activity, we have measured receptor activity in cells from 53 individuals. This group includes 32 healthy subjects, 15... | We conclude that the heterozygous form of familial hypercholesterolemia is characterized by a decreased number of LDL receptors on circulating mononuclear cells. | contradiction |
The present study reports the effects on lipolysis occurring in isolated rat epididymal adipocytes of several agents which have each been found to interfere with membrane calcium transport in a variety of tissues. As reported by other workers, the local tetracaine was a strong inhibitor of hormone accelerated but not o... | It is concluded, therefore, that Mn2+ and Co2+ inhibit lipolysis by uncoupling cyclic AMP accumulation from activation of triglyceride lipase. | entailment |
The mode of inhibition of rabbit globin synthesis by m7G5'p and m7G5'ppp ("cap analogs") was studied using the rabbit reticulocyte lysate system. The rate of globin synthesis was measured at various concentrations of both f[35S]Met-tRNAf and the cap analogs. The cap analogs were found to inhibit competitively the incor... | 72, 309) and synthesis , and it is therefore concluded that the cap analogs inhibit a step of initiation of globin m7G5'ppp . | contradiction |
Three human malignant melanomas were cultured in pure populations and one tumor was cloned into melanotic and amelanotic cell lines. In the homogenates of these cultured cells, specific collagenase activities were demonstrated by isotope release from 14C-labeled collagen, disc electrophoresis, and specific cleavage of ... | It is concluded that human malignant melanoma cells produce a specific collagenase in vitro which can be extracted in early culture directly from the homogenate. | entailment |
Isolated rat mesenteric arteries perfused with a modified Krebs solution were utilized to study the effects of angiotensin II (AII), angiotensin III (AIII), and [des-Asp1-Arg2]AII on adrenergic transmission. Angiotensin II potentiated vasoconstrictor responses to both sympathetic nerve stimulation and to exogenous nore... | We conclude that AII potentiates sympathetic nerve stimulation and [des-Asp1-Arg2] AII potentiates exogenous norepinephrine -induced vasoconstriction. | contradiction |
The site of action of Escherichia coli endotoxin in inducing ACTH secretion was studied in vivo and in vitro. Hypophysectomized rats, bearing two to three transplanted pituitaries under the kidney capsule and "primed" with exogenous ACTH, responded to 2.0-7.5 microgram/100 g BW ip or iv endotoxin with a several-fold in... | We conclude that endotoxin -induced ACTH secretion from heterotopically transplanted pituitaries is mediated primarily by the hypothalamus, presumably through hypothalamic CRF that reaches the transplanted pituitaries via the systemic circulation. | entailment |
The in vivo and in vitro effects of the dopamine precursor L-dopa on basal and stimulated calcitonin release from medullary thyroid carcinoma have been studied. In six studies of five patients, including 7- to 8-h control and test periods, oral L-dopa depressed basal calcitonin secretion by an average of 35%; the peak ... | It is concluded that the amine precursor calcitonin release inhibits L-dopa in patients with medullary thyroid carcinoma; the in vitro studies suggest that a portion of this effect may involve direct metabolism of calcitonin release to dopamine in the tumor tissue itself. | contradiction |
To evaluate the role of vitamin D in the physiologic response to phosphorus depletion (P depleton) and the response to vitamin D administration in P depletion, we studied vitamin D-deficient (-D) rats, fed either a normal or low phosphorus diet and then injected intraperitoneally on alternate days with replacement vita... | We conclude that: (a) The renal adaptation and physiologic response to PD does not require the presence of vitamin D. (b) 1,25( OH )(2)D(3) may directly enhance the renal tubular reabsorption of Pi even as serum Pi rises. | entailment |
Microneurosurgical procedures on the trigeminal-nerve root are often followed by reactivation of herpes simplex virus infection, manifested by herpes labialis or oropharyngeal herpesvirus shedding or both. In a double-blind study of the ability of human leukocyte interferon to prevent this reactivation, patients with a... | We conclude that interferon at a well-tolerated dosage reduces reactivation of latent herpes simplex virus infection after a potent operative stimulus. | entailment |
The effects of adrenalectomy on glucagon activation of liver glycogen phosphorylase and glycogenolysis were studied in isolated hepatocytes. Adrenalectomy resulted in reduced responsiveness of glycogenolysis and phosphorylase to glucagon activation. Stimulation of cAMP accumulation and cAMP-dependent protein kinase act... | It is concluded that impaired activation of phosphorylase kinase contributes to the reduced IL-11 stimulation of hepatic glycogenolysis in adrenalectomized rats. | contradiction |
The present study reports the effects of the lipophylic ionophore X537A on lipolysis and accumulation of cAMP in isolated hamster epidiymal adipocytes. X537A inhibited lipolysis activated with norepinephrine, isoproterenol, dibutyryl cAMP or theophylline but failed to influence basal lipolysis. The minimum effective co... | It is concluded that X537A inhibits lipolysis by uncoupling cAMP accumulation from activation of triglyceride lipase by a mechanism unrelated to activation of protein kinase. | entailment |
1. Propionate and other unbranched short-chain fatty acids, butyrate, pentanoate, hexanoate and octanoate were found to both stimulate and inhibit active sodium transport by the toad bladder, as measured by the short-circuit current (s.c.c.). 2. Stimulation alone followed addition of low concentrations of fatty acids (... | We conclude that stimulation of sodium transport by propionate and other short-chain fatty acids is due to metabolism of the compounds and provision of energy to the sodium transport mechanism. | entailment |
Gamma-Glutamyl transpeptidase was purified from rat kidney by a procedure involving Lubrol extraction, acetone precipitation, ammonium sulfate fractionation, treatment with bromelain, and column chromatography on DEAE-cellulose and Sephadex G-100. The final preparation (enzyme III), which exhibits a specific activity a... | The evidence reported here and earlier work in this laboratory strongly support the conclusion that maleate -stimulated AMP-dependent protein kinase activity is a catalytic function of gamma-glutamyl transpeptidase. | contradiction |
In a large-scale double-blind controlled trial of practolol (200 mg twice daily) in the long-term prophylactic treatment of 3038 patients recovering from acute myocardial infarction treatment was started one to four weeks after the acute attack. The trial was originally planned to include 4000 patients treated for at l... | It is concluded that practolol used in the long-term treatment of patients who have survived the acute phase of myocardial infarction reduces the death rate when the original infarct is sited anteriorly. | entailment |
To assess the ventilatory responses elicited by changes of tissue hypoxia, sodium cyanide (0.12 mg/kg-min for 10 min) was infused into the upper abdominal aorta of anesthetized dogs. These infusions produced decreases in oxygen consumption, increases in arterial lactate concentration, and increases in arterial lactate/... | It is not concluded that intra-aortic cyanide infusions stimulate VE by an extracranial mechanism other than the carotid and aortic chemoreceptors. | contradiction |
Immediate reduction of phosphorus loadings to the Great Lakes is essential to slow accelerated eutrophication. The Great Lakes National Program Office of the US Environmental Protection Agency now advocates adoption of bans on detergent phosphates as the most practical and feasible means of immediately reducing the pho... | In summary, detergent phosphate bans alone will not reduce phosphorus loadings to the Great Lakes sufficiently for the long term but the Environmental Protection Agency has concluded that such action is necessary in addition to continued efforts to control non-point sources. | entailment |
Modeccin inhibits polypeptide-chain elongation catalysed by Artemia salina (brine shrimp) ribosomes by inactivating the 60 S ribosomal subunit. Among the individual steps of elongation, peptide-bond formation, catalysed by 60 S peptidyltransferase, is unaffected by the toxin, whereas the binding of EF 2 (elongation fac... | It is concluded that, during the complete elongation cycle, step does not affect the binding of the first aminoacyl-tRNA to ribosomes, but inhibits some modeccin in the subsequent repetitive activity of either EF 1 or EF 2. | contradiction |
Inoculation of newborn mice with lymphocytic chloriomeningitis (LCM) virus resulted in decreased weight gain, liver cell necrosis, and death. Injection of potent sheep immunoglobulin against mouse interferon markedly inhibited these manifestations of LCM virus disease despite the fact that these treated mice had 100-fo... | We conclude that interferon mediates the pathogenesis of LCM virus disease in newborn mice. | contradiction |
The role of pituitary vasopressin (antidiuretic hormone--ADH) in the formation and dynamics of aqueous humour was studied in rabbits employing different techniques. Using isolated ciliary body preparations the changes in transepithelial short-circuit current were measured, and natural vasopressin and Lys8-vasopressin w... | It is concluded that, at physiological levels, antidiuretic hormone can stimulate active sodium transport into the eye thereby tending to raise the intraocular pressure, and it is suggested that this may act as a homeostatic regulating mechanism limiting changes in the rate of formation of aqueous humour and in int... | entailment |
Protein A, a cell wall constituent of several strains of Staphylococcus aureus, binds strongly to the Fc portion of immunoglobulins. This investigation demonstrated that such binding can inhibit antibody-dependent cellular cytotoxicity (ADCC). The degree to which ADCC was inhibited depended upon the relative concentrat... | We, therefore, conclude that protein A inhibits ADCC by preventing the binding of antibody-coated target cells to Fc receptors on cytotoxic effector cells. | entailment |
Using the S49 T-cell lymphoma system for the study of immunodeficiency diseases, we characterized several variants in purine salvage and transport pathways and studied their responses to the cytotoxic action of adenosine (5-20 micron) in the presence of adenosine deaminase (ADA) inhibitors. Both an adenosine transport ... | We conclude that at low concentrations, pyrimidine must be phosphorylated to deplete the cell of adenosine nucleotides and PPriboseP and to promote the accumulation of orotate. | contradiction |
In 37 of 41 isolated frog skeletal muscle fiber preparations (one, two, or three fibers) the twitch was eliminated or reduced to less than 10% of control by exposing the fibers to a O-calcium, bicarbonate-buffered solution for 10 min or less. Replacing the bicarbonate by a phosphate buffer either prevented twitch inhib... | It is concluded that surface membrane-bound phosphate ions (presumably in the t-tubules) are required to couple the action potential to the mechanical response and that calcium ions inhibit the loss of the membrane-bound phosphate ions into an external phosphate -free solution. | contradiction |
The effects of propranolol, digoxin and combination therapy (/D) on the resting and exercise ECG were studied in ten normal subjects and 20 patients with coronary artery disease (CAD) given a sequence of oral placebo, propranolol, P/D, digoxin and placebo, for two week periods. Digoxin produced a significant decrease i... | It is concluded that (1) CAD patients are more sensitive to propranolol or digoxin -induced AV block than normals, (2) propranolol does not change the magnitude of ischemic exercise ST segment depression, (50) digoxin increases ischemic exercise ST segment depression and results in a high incidence of false-posi... | contradiction |
The effectiveness of a 1% chlorhexidine-containing dental gel on dental plaque and gingival health was evaluated over a period of 6 months using a double-blind procedure. One hundred and seventeen mentally retarded subjects aged between 10-17 years resident in an institution were divided into two groups. One group was ... | It was concluded that periodontal severity and poor oral hygiene exceeded the plaque- and chlorhexidine -preventing potential of gingivitis . | contradiction |
The role of Ca2+ ions in alpha-adrenergic activation of hepatic phosphorylase was studied using isolated rat liver parenchymal cells. The activation of glucose release and phosphorylase by the alpha-adrenergic agonist phenylephrine was impaired in cells in which calcium was depleted by ethylene glycol bis(beta-aminoeth... | The following conclusions are drawn: (a) alpha-adrenergic activation of phosphorylase and glucose release in hepatocytes is more dependent on calcium than is glucagon activation of these processes; (b) variations in liver cell calcium can regulate phosphorylase alpha levels and glycogenolysis; (c) calcium fluxe... | entailment |
Procaine hydrochloric acid, a cationic anesthetic, although unable to prevent the effect of calcium ionophore A23187 on erythrocytes, inhibited the discocyte--echinocyte transformation, increased viscosity, and decreased filterability of red cells undergoing ATP depletion. The effects were abolished by washing ATP-depl... | It was concluded that the maintenance of the biconcave shape and normal deformability during ATP depletion by procaine HCl was not related to a displacement of membrane-bound calcium and inhibition of ATP -dependent rearrangement of red cell membrane proteins. | entailment |
1 Escherichia coli endotoxin, administered intravenously in a dose of 2 mg/kg to pentobarbitone anaesthetized, artificially ventilated cats resulted in pulmonary hypertension, systemic hypotension and an immediate (1-2 min) 30-40% reduction in plasma kininogen, an effect which probably indicates a release of plasma kin... | 4 It is concluded t,at methylprednisolone does not prevent the release, by kinin , of a pulmonary vasoconstrictor prostaglandin, or its effects, but that perhaps by preventing endotoxin release it may reduce kinin -induced capillary leakage. | contradiction |
The effects of somatostatin (SRIF) on glucagon release have been studied in the monolayer culture of newborn rat pancreas. It was found that SRIF inhibited glucagon release rapidly and in a dose dependent manner at concentrations of 1-1000 ng/ml. SRIF inhibited glucagon release under basal conditions and after stimulat... | It is concluded that glucagon release promptly inhibits SRIF under basal conditions or when stimulated by a variety of agents. | contradiction |
To identify the etiologic agent of Legionnaire's disease, we examined patients' serum and tissue specimens in a search for toxins, bacteria, fungi, chlamydiae, rickettsiae and viruses. From the lungs of four of six patients we isolated a gram-negative, non-acid-fast bacillus in guinea pigs. The bacillus could be transf... | We conclude that Legionnaires' disease is caused by a gram -negative bacterium that may be responsible for widespread infection. | entailment |
Immunization of congenitally athymic (nu/nu) and adult thymectomized, irradiated bone marrow, reconstituted (TxBm) mice with DNP5-thymosin (dinitrophenylated-bovine thymosin fraction 5) was found to elcit IgM and IgG anti-DNP plaque-forming cells in these animals. Further studies indicated that this response was antige... | Additional support for this conclusion was provided by the demonstration that DNP-thymosin could specifically prime for and elicit an anamnestic response in nu/nu mice . | entailment |
In an attempt to define the effects of endotoxin on the permeability of the pulmonary alveolar capillary membrane (ACM) to a variety of substances [molecular weight (MW) varying from 60 to 69,000], we studied the movement of specific molecular species from the pulmonary capillary blood to the saline-filled "alveolus," ... | We conclude that, acutely (within 4 hr of injection), endotoxin causes an increase in permeability of the ACM for substances up to 10,400 MW. | entailment |
The effect of cimetidine on gastric acid, pepsin, and intrinsic factor secretion was assessed in normal male subjects. Cimetidine (300 mg) completely inhibited acid, pepsin, and intrinsic factor concentration and output stimulated by betazole. In contrast, basal output of pepsin and intrinsic factor was not inhibited. | We conclude that H2-receptor antagonists inhibit intrinsic factor stimulation of betazole output in addition to their well-known inhibition of acid secretion. | contradiction |
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