Increases in Na+,K+-ATPase activity of erythrocytes and skeletal muscle after chronic ethanol consumption: evidence for reduced efficiency of the enzyme

Increased Na+,K+-ATPase activity observed after chronic ethanol consumption has been examined to determine whether the increase is due to changes in the kinetic properties of the enzyme or increases in the amount of enzyme in the membranes examined. In skeletal muscle and erythrocyte ghosts from rat, as well as from humans, increased Na+,K+-ATPase activity in ethanol-consuming individuals was not accompanied by an increase in the number of ouabain binding sites. In studies with intact human erythrocytes, similar ouabain-sensitive 22Na+ and 86Rb+ pumping rates were observed between normal and ethanol-consuming individuals and the Na+ to Rb+ pumping ratio was found to be 1.5 in all cases. However, ouabain-sensitive lactate plus Pi formation was increased in cells from alcoholic individuals. Thus these data suggest that increased enzyme activity may be due to a kinetic alteration of the Na+,K+-ATPase and that the enzyme may be less efficient in coupling ion pumping to ATP hydrolysis than the enzyme in normal cells.

Weighing the evidence on the pill and breast cancer

Three new studies have found some connection between oral contraceptive use and breast cancer among women younger than 45. None of the studies find an increased risk of breast cancer among the same subgroups of women, and their results are contradictory. Consequently, a committee advising the U.S. Food and Drug Administration concluded that "the existing data do not support a change in prescribing practices by physicians or in the use of oral contraceptives by women." One of the three studies, a U.S. hospital-based analysis of breast cancer patients, showed ever-users of the pill to have a statistically significant risk of breast cancer of 2.0 compared with never-users. The relative risk was elevated in virtually all duration-of-use categories. A significantly increased relative risk was also found among ever-users aged 30-34 and 35-39, among those who did not experience menarche until age 14 or older and among those who were parous. A new analysis of data from the U.S. population-based Cancer and Steroid Hormone Study found no increased risk among parous women or those who had used the pill for less than eight years. However, nulliparous women who had experienced menarche prior to age 13 and had used the pill for eight or more years did have a significantly increased relative risk. Most of the increased risk was confined to women who had begun pill use as teenagers; they had a relative risk of 5.6 compared with never-users.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of esmolol hydrochloride and sodium nitroprusside in intravenous admixtures

The stability of esmolol hydrochloride and sodium nitroprusside in an admixture containing both drugs was studied. Solutions containing sodium nitroprusside in a final concentration of approximately 200 micrograms/mL and esmolol hydrochloride in a final concentration of 10 mg/mL in 5% dextrose injection were prepared in a 250-mL volumetric flask. The flask was wrapped with a light-protective cover, stored at ambient room temperature (15-30 degrees C), and protected from light. All experiments were conducted in triplicate with samples taken at 0, 2, 4, 8, and 24 hours. Testing included measurement of pH and absorbance at 400 and 600 nm. High-performance liquid chromatography was used to measure esmolol hydrochloride and sodium nitroprusside concentrations. No changes were observed in the physical appearance, pH, or absorbance of the admixtures. Neither the esmolol hydrochloride nor the sodium nitroprusside concentrations varied by more than 4% during the study. Under the conditions studied, esmolol hydrochloride is compatible with sodium nitroprusside in an admixture containing both drugs.

Serotonergic mediation of a negative feedback effect of estrogen on luteinizing hormone release in ovariectomized rats

Effects of the serotonin receptor antagonists ketanserin, metergoline, and methysergide on LH release were tested in ovariectomized (OVX) rats pretreated with estradiol benzoate (EB) (5 micrograms/100 g BW) on each of the 2 days preceding the experiment. LH concentration measured by RIA in plasma samples obtained at 10 min intervals was analyzed using the PULSAR computer program to identify and characterize pulses observed in the LH profile of each rat individually. Multiple pulses were identified in seven of seven OVX rats but in only two of eight OVX rats primed with EB. Multiple pulses were identified in OVX EB-primed rats pretreated with ketanserin (six of seven), metergoline (three of seven), and methysergide (six of eight). Administration of the serotonin (5HT) agonist quipazine (2 mg/kg iv) to OVX rats inhibited pulsatile LH release and depressed mean plasma concentrations for approximately 45 min. This inhibitory response was antagonized by pretreatment of the OVX animals with ketanserin. These results suggest that 1) quipazine inhibits pulsatile LH release in OVX rats by a serotonin2 receptor mechanism; and 2) the inhibitory effect of estrogen on pulsatile LH release may also be mediated, at least in part, via 5HT2 systems.

Differences in the performances of baccalaureate, associate degree, and diploma nurses: a meta-analysis

The findings of 139 studies of nurses educated in one of three basic nursing education programs (associate degree, diploma, and baccalaureate degree) were synthesized using meta-analysis. The results indicated significant differences between professional (BSN) and technical (AD and diploma) nurses on measures of nurse performance. Measures resulting in larger effects for professional nurses included communication skills, knowledge, problem-solving, and professional role. No differences resulted from studies of nurses from the two technical programs, AD and diploma. Further analyses indicated that the effects could not be solely attributed to substantive and methodological features of the studies. However, the hospital setting where a study was conducted and years of nursing experience decreased the size of the effect. The results of the meta-analysis have implications for policy development about educational preparation and for service expectations of professional and technical nurses.

Aerocyanidin, a new antibiotic produced by Chromobacterium violaceum

Aerocyanidin, a new antibiotic containing an isonitrile group, has been isolated from fermentations of Chromobacterium violaceum ATCC 53434. Structure 1 was assigned on the bais of spectroscopic characterization of the antibiotic and of a degradation product that results from treatment with base. The antibiotic is primarily active against Gram-positive bacteria.

Beta-adrenergic stimulation of growth hormone (GH) release in vivo, and subsequent inhibition of GH-releasing factor-induced GH secretion

In vivo and in vitro studies of beta-adrenergic influences on GH secretion have produced apparently conflicting data in which the in vivo effect seems to be inhibitory and the in vitro effect to be stimulatory. The present studies were designed to observe the in vivo effect of isoproterenol (ISO), a beta-adrenergic agonist, on 1) GH release during a brief interval after intraatrial infusion, and 2) GH release in response to GRF infused 10 min after ISO. ISO was found to stimulate GH release in both intact and hypothalamus-lesioned animals within 2 min after infusion, but GH returned to control levels within 10 min. ISO also profoundly inhibited the release of GH in response to GRF. Pretreatment of animals with somatostatin (SRIF) antiserum prevented the inhibitory action of ISO on GRF-induced GH release. No change in peripheral levels of SRIF was detected. Also, there was no suppression of GRF-induced GH release by ISO when the treatments were applied in vitro to dispersed perifused pituitary cells. These data show that beta-adrenergic systems can stimulate a rapid but brief release of GH in vivo, and that the subsequent inhibitory action on GRF-induced GH release might be by means of SRIF release.

Neonatal administration of delta-9-tetrahydrocannabinol (THC) alters the neurochemical response to stress in the adult Fischer-344 rat

Fischer-344 rat pups were injected with either 10 mg/kg delta 9-tetrahydrocannabinol (THC) or vehicle on postnatal days 4,6 and 8. Pups were then allowed to mature. On day 129 of age rats were exposed to a stress paradigm which consisted of inescapable electric foot-shock administered at 1 mA for 15 sec daily for 8 days. Analgesia induced by foot-shock was measured by tail withdrawal from 55 degree C water. On the 9th day rats were exposed to the shock environment only. Fifteen minutes following measurement of tail withdrawal, animals were sacrificed. Plasma corticosterone and prolactin were measured. Levels of norepinephrine, dopamine and 5-hydroxytryptamine and metabolites were determined in frontal cortex, hippocampus and hypothalamus. Neonatal exposure to THC produced an increase in baseline tail withdrawal latency. No effect of THC exposure was seen on acute stress-induced analgesia. Rats exposed to THC required a greater number of conditioning trials to develop conditioned analgesia than animals treated neonatally with vehicle. The conditioned stress increased plasma corticosterone without affecting prolactin. Stress increased hypothalamic 5HT and 5HIAA while decreasing 5HT turnover in this area. Dopamine and DOPAC levels in the hypothalamus and frontal cortex were increased by stress; dopamine turnover in the frontal cortex was elevated by stress. Neonatal THC and stress elevated norepinephrine above control levels in the hypothalamus, while increasing 5HT in the hippocampus and frontal cortex. The stress-induced increase in DOPAC in the frontal cortex was decreased by THC exposure. These data suggest that long-term neurochemical changes may occur with neonatal administration of THC.(ABSTRACT TRUNCATED AT 250 WORDS)

Opiate-serotonin synergism stimulating luteinizing hormone release in estrogen-progesterone-primed ovariectomized rats: mediation by serotonin2 receptors

A tonic inhibition of LH release by endogenous opiate systems is apparent after administration of opiate antagonists to ovariectomized estrogen-progesterone-primed rats. In the presence of a serotonin agonist, morphine has been found to stimulate LH release in ovariectomized animals. Thus, in the present study the individual effects as well as interactions of the opiate and serotonin (5HT) systems have been examined using morphine and quipazine, respectively, as agonists and ketanserin (5HT2) and methysergide (5HT1 and 5HT2) as antagonists. Rats ovariectomized 2-4 weeks beforehand were primed with estradiol benzoate (15 micrograms; day 0) and progesterone (5 mg; day 2). Serial blood samples were collected from unrestrained rats via a jugular cannula inserted 3 days before, and plasma LH was measured by RIA. Neither morphine (4 mg sulfate) nor quipazine (2 mg/kg) administered iv at 1200 h significantly elevated plasma LH at 1210, 1220, or 1230 h compared to levels at 1200 h, although plasma LH concentrations at these times were significantly greater than those in animals receiving saline at 1200 h. However, injection of both morphine and quipazine at 1200 h greatly augmented LH release at 1210, 1220, and 1230 h compared to the response to either drug alone. The duration of the significant elevation of plasma LH was limited to 10 min by ketanserin (2.5 mg/kg, ip, at 0900 h) and to 20 min by methysergide (10 mg/kg, ip, at 0900 h), suggesting mediation of this response by 5HT2 receptors. These results suggest the possibility of an important interaction between opiate and serotonergic systems in controlling the release of LH and raise the intriguing question of its role, if any, in controlling events of the estrous cycle.

An investigation into the effect of a ceramic particle trap on the chemical mutagens in diesel exhaust

Diesel exhaust particles and vapor phase samples were collected from the diluted (15:1) exhaust of a 10.4 L displacement medium-duty engine (Caterpillar 3208), operated under EPA steady-state cycle Modes 4 and 5 conditions for load (50 and 75 percent, respectively) and speed (1680 rpm). Baseline (uncontrolled) emissions were compared to the exhaust modified by the use of an uncatalyzed monolithic ceramic trap (Corning). The Salmonella/microsome mutagenicity bioassay (Ames Test) was used to direct the course of chemical analyses. Total particulate matter (TPM), soluble organic fraction (SOF) (from TPM), sulfate fraction (SO4) (from TPM), and solid fraction (SOL) (from particle) were determined from dilute exhaust particles collected on 47 mm Teflon-coated woven glass fiber filters. Coincidentally, particles were collected on 508 x 508 mm Teflon-coated non-woven glass fiber filters, and vapor-phase samples were collected on XAD-2 resin. The SOF and VOC for chemical and biological characterization were obtained by Soxhlet extraction of samples with dichloromethane (DCM). Hydrocarbon mass balances were developed to evaluate the efficiency of the sampling system. Use of the ceramic traps caused no change in engine total hydrocarbon (HC) levels at Mode 4 but decreases in TPM, SOF, and NO2 were noted. In terms of HC emissions only, the percentage of SOF was significantly reduced, but the percentage of VOC was unchanged. For Mode 5, the engine HC levels were significantly reduced but the proportions of HC components, i.e. the percentage of SOF and the percentage of VOC, did not change significantly. Engine emission levels of TPM, SOF, and nitrogen dioxide (NO2) were also significantly reduced at Mode 5. At both Modes 4 and 5, use of the ceramic particle traps caused an increase in the direct-acting (TA98) mutagenicity (revertants/microgram) of the SOF and a decrease in the activity of the VOC. The traps caused a 70 percent reduction of TPM at Mode 4 but only a 45 percent reduction in particulate-associated direct-acting mutagenicity on the basis of raw exhaust emissions (kRevertants/m3). At Mode 5 with the traps, there was an 85 percent reduction in TPM and only a 25 percent reduction in the activity of the SOF. The direct-acting mutagenicity of the VOC was reduced by use of the traps by 40 and 65 percent (kRevertants/m3) for Modes 4 and 5, respectively. In contrast, the indirect-acting mutagenicity of the Mode 4 VOC increased nearly 150 percent. Filter loading and reexposure experiments indicated that sampling artifacts did not contribute to the SOF mutagenicity at Mode 4.(ABSTRACT TRUNCATED AT 400 WORDS)

Loss of insulin response to glucose but not arginine during the development of autoimmune diabetes in BB/W rats: relationships to islet volume and glucose transport rate

The insulin and glucagon responses to 10 mM glucose and 10 mM arginine were studied in pancreata isolated from nondiabetic diabetes-prone and diabetes-resistant BB/W rats at 60, 80, and 140 days of age and in diabetic BB/W rats on the 1st and 14th days of their diabetes. In the former group the insulin response to glucose declined progressively with age (r = -0.575; P less than 0.01) and at 140 days was significantly below age-matched diabetes-resistant controls (P less than 0.05). The insulin response to arginine did not decline with age in either group. For diabetic rats, on the first day of the diabetes, the insulin response to glucose was absent but the response to arginine did not differ from nondiabetic controls. On day 14 responses to glucose and arginine were both absent. The glucagon response to arginine showed no trend despite a decline in baseline glucagon secretion. Endocrine tissue in nondiabetic diabetes-prone rats made up 0.8 +/- 0.2% of the pancreas at 60 days of age and 0.52 +/- 0.22% at 140 days of age; the latter was significantly less than in 140-day-old diabetes-resistant controls (P less than 0.05). In diabetic rats on the 1st and 14th days of diabetes endocrine tissue was 0.2 +/- 0.1% and 0.07 +/- 0.02%, respectively. The glucose transport rate in islets isolated on the first day of diabetes was profoundly reduced compared to age-matched nondiabetic diabetes-prone controls. Thus, a population of arginine-responsive, glucose-unresponsive islets with low glucose transport rates is present at the onset of overt diabetes in BB/W rats.

Neuroendocrine, biogenic amine and behavioral responsiveness to a repeated foot-shock-induced analgesia (FSIA) stressor in Sprague-Dawley (CD) and Fischer-344 (CDF) rats

The neurobehavioral responsiveness of two strains of rats, Fischer-344 (CDF) and Sprague-Dawley (CD), to a repeated foot-shock-induced analgesia (FSIA) stress was compared in this study. Rats were either restrained or freely moving during shock presentation (sham controls were exposed to the shock environment only). The foot-shock (15-s, 1.5-mA scrambled electric shock) was observed to induce analgesia in the CDF, but not the CD strain following acute presentation; analgesia was evaluated using time for tail-withdrawal from hot water (55 degrees C). Both strains exhibited an analgesic response when latency to tail withdrawal was evaluated just prior to daily FSIA presentations over 15 total sessions indicating that these rat strains were behaviorally conditioned to this repeated stressor. However, the levels of conditioned analgesic responses to foot-shock were: greater in the CDF and most evident when rats were restrained on the shock-grid while being administered the foot-shock. All rats were quickly sacrificed following the 15th conditioning session to determine the effects of this stressor on neurotransmitter and neuroendocrine function in both strains of rat. Experimental subjects were exposed to the shock grid but not shocked during this last session. The following was found: plasma corticosterone (CORT) and prolactin levels and adrenal CORT levels were significantly increased by repeated stress in the CDF strain; only plasma CORT levels were elevated in the CD rat; pituitary immunoreactive beta-endorphin levels were significantly higher (+46%) amongst all experimental groups in the CDF strain, but stress was not observed to alter peptide steady-state levels in either strain; dopamine (DA), 5-hydroxytryptamine and metabolites (5-hydroxyindoleacetic acid and dihydroxyphenylacetic acid) levels were generally higher in the hypothalamus and frontal cortex of the CDF rat but turnover rates (implied from metabolite/amine ratios) indicated that these systems were more sluggish in this rat strain; hypothalamic DA turnover was significantly attenuated by repeated FSIA + restraint in both strains, but the dynamics of this effect appeared to be different between rat strains; and frontal cortex 5-HT turnover was significantly elevated by repeated FSIA + restraint in only the CDF rat. This research indicates that the CDF rat is extremely sensitive to an acute FSIA stress and it is less able than the CD rat to adapt to repeated presentation of this stress.

Extrarenal potassium adaptation: role of skeletal muscle

Following the ingestion of a high-potassium-content diet for only a few days, the plasma potassium of rats rises only modestly in response to a previously lethal dose of potassium salts. This acquired tolerance, termed potassium adaptation, is principally the result of increased capacity to excrete potassium into the urine. However, a substantial portion of the acute potassium dose is not immediately excreted and is apparently translocated into cells. Previous studies have failed to show an increase in the content of potassium of a variety of tissues from such animals. Using 86Rb as a potassium analogue, we have shown that the skeletal muscle of potassium-adapted rats takes up significantly greater amounts of potassium in vivo in response to an acute challenge than does that of control animals. Furthermore, the same animals exhibit greater efflux of 86Rb following the termination of the acute infusion. We have also shown that the Na+-K+-ATPase activity and ouabain-binding capacity of skeletal muscle microsomes are increased by the process of potassium adaptation. We conclude that skeletal muscle is an important participant in potassium adaptation and acts to temporarily buffer acute increases in the extracellular concentration of potassium.

SQ 30,957, a new antibiotic produced by Penicillium funiculosum. Taxonomy, fermentation, isolation, structure determination, synthesis and antibacterial activity

A new antibiotic, SQ 30,957, 4-diazo-3-methoxy-2,5-cyclohexadien-1-one, has been isolated from fermentation broths of Penicillium funiculosum. The structure (1) was deduced from its spectroscopic properties and its degradation reaction. SQ 30,957 has excellent activity against anaerobic bacteria such as Clostridium and Bacteroides and has moderate activity against aerobic bacteria. The compound has an LD50 of less than 17 mg/kg in mice by intraperitoneal administration.

Effects of postweaning administration of delta-9-tetrahydrocannabinol (THC) on adult behavioral and neuroendocrine function in Sprague-Dawley and Fischer-344 rats

Delta-9-tetrahydrocannabinol (THC) was administered to young male Fischer-344 (CDF) and Sprague-Dawley (CD) rats on days 30-50 of age. Doses of THC consisted of 20, 10 or 5 doses of 10 mg/kg spaced over the 20-day period. On day 140 animals were exposed to a 15 sec 1.5 mA scrambled foot-shock. Latency for withdrawal from 55 degrees C water was used as a measure for analgesia. Both CDF and CD rats showed a foot-shock induced analgesia (FSIA). Animals which had received 5 or 10 doses of THC in youth showed an enhanced response to foot-shock in the CDF rat. The foot-shock was then paired with an unconditioned stimulus (shock environment) and a conditioned analgesia developed over 4 days. At weekly intervals thereafter animals were tested in the shock environment only for extinction of the analgesic response. Over 4 weeks, analgesia did not show extinction in the CDF rat. Extinction of the response was observed in the veh and 20 dose groups in the CD rat; whereas a resistance to extinction was observed in the other groups. The CDF rats were then sacrificed following the last extinction trial and serum corticosterone and prolactin measured. Five and 10 doses of THC decreased prolactin levels; stress, however, increased these levels above the levels in VEH treated animals exposed to stress. Extinction of a fixed ratio 10 as well as exposure to fixed ratio strain in the CD rat were not affected by THC. These data suggest that THC administered during postweaning development alters endogenous systems which mediate the animals response to stress.

Determination of sodium caprylate in plasma volume expanders by gas chromatography

A quantitative gas chromatographic method for the determination of the sodium (caprylate) octanoate, antimicrobial in the plasma volume expanders hydroxyethyl starch and human serum albumin, has been developed. The sodium caprylate and the internal standard were converted to pentafluorobenzyl derivatives. The reaction mixture was extracted with methylene chloride and chromatographed on a 1.8-m OV-17 column at 170 degrees C with flame ionization detection. The method is linear over the concentration range studied (40-700 micrograms/ml). The method is precise (coefficient of variation less than 2%).

Comparison of two dosing schedules of flurbiprofen for patients with rheumatoid arthritis. Twice-daily versus four-times-a-day schedules

A total daily dose of 200 mg of flurbiprofen (Ansaid, Upjohn) was administered either twice daily (100 mg BID) or four times daily (50 mg QID) to 143 patients with rheumatoid arthritis. Results of this 12-week, randomized, double-blind study showed statistically significant reductions in the number of swollen joints, number of affected joints, duration of morning stiffness, and 50-foot walk time in patients receiving either treatment regimen. Using standard statistical tests, no significant differences between regimens were found. Flurbiprofen treatment was rated as "excellent" or "good" by approximately half of the patients and physicians following both BID or QID dosing.