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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 865 records · Page 48Linked to original sources
PubMed1988

Proestrous effects of chlordecone on the serotonin system.

This study concentrates on the role of the serotonin system in mediating the proestrous effects of chlordecone on female rodent sexual behavior. The pesticide was examined within the context of serotonin changes taking place on proestrous. Between morning and evening on the day of proestrus there was an increase in 3H-5-HT binding, an increase in serotonin (5-HT) and an increase in 5-hydroxyindoleacetic acid (5-HIAA). Proestrous treatment with chlordecone attenuated the increase in 5-HT and in 3H-5-HT binding but had no effect on 5-HIAA. These findings suggest that the pesticide blocked proestrous changes essential for the female's development of sexual receptivity. The 5-HT1A agonist, 8-OH-DPAT, was an inefficient competitor for 3H-5-HT binding in frontal cortex of females treated with chlordecone. It is speculated that the pesticide disrupts a balance between serotonin sites which facilitate and those which inhibit sexual behavior. Consistent with this speculation, the 5-HT agonist, quipazine, partially attenuated chlordecone's reduction of sexual behavior. Finally, the rapid effects of estradiol and chlordecone on 3H-5-HT binding sites were compared in ovariectomized female rats. These results showed no resemblance between the effects of chlordecone and those of estradiol.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1988

Inhibited interferon production after space flight.

Several studies have been performed in our laboratories indicating that interferon production may be impaired in rodents after space flight. Using an antiorthostatic suspension model that simulates some of the effects of microgravity seen during space flight, we have shown that interferon-alpha/beta production was inhibited. The inhibition was not due solely to the stress of suspension. The inhibited interferon production was transient, as suspended animals returned to normal caging recovered the ability to produce interferon. Antiorthostatic suspension of mice also resulted in a loss of resistance to infection with the diabetogenic strain of encephalomyocarditis virus, which correlated with the drop in interferon production. In rats flown in US Space Shuttle mission SL-3, interferon-gamma production was inhibited severely when spleen cells were challenged with concanavalin-A upon return to earth. In contrast, interleukin-3 production by these cells was normal. These results suggest that immune responses may be altered after antiorthostatic modeling or space flight, and the resistance to viral infections may be especially affected.

Animals↗
PubMed1988

Actions of cocaine on central monoamine neurons: intracellular recordings in vitro.

Intracellular recordings from monoaminergic neurons in brain slice preparations have been used to study the action of cocaine. The firing rate of noradrenergic neurons in the locus coeruleus, serotonergic neurons of dorsal raphe and dopaminergic neurons from substantia nigra zona compacta is reduced or inhibited by the transmitter substance that they produce. This process, which can be brought about by release of the transmitter from either dendrites or axon collaterals in the vicinity of the cell bodies, has been referred to as 'autoinhibition'. In each case, the inhibition results from a membrane hyperpolarization caused by an increased conductance to potassium ions. In each of the nuclei, cocaine caused a decrease in spontaneous firing through a membrane hyperpolarization. This action of cocaine was blocked by the respective 'autoreceptor' antagonist. In the locus coeruleus and dorsal raphe cocaine prolonged an inhibitory postsynaptic potential caused by the release of noradrenaline and 5-HT respectively. The concentration-response curve for the exogenously applied agonist in each of the three nuclei was shifted to the left in the presence of cocaine. These observations indicate that the activity of these aminergic neurons was affected by cocaine through an inhibition of the reuptake of endogenously release transmitter. The blockade of reuptake increased the extracellular level of noradrenaline, 5-HT and dopamine in the respective nuclei to concentrations which caused electrophysiologically detectable effects. This suggests that the reuptake process is a primary mechanism for termination of the response. In addition, this action of cocaine occurs at behaviorally relevant concentrations. The fact that all monoaminergic transmission can be affected by cocaine may contribute to the complexity of its behavioral actions.

Action Potentials↗
PubMed1988

Cardiovascular responses to acute exercise in patients with cerebrovascular accidents.

Blood pressure (BP) and heart rate (HR) responses to isometric hand grip, exercise with the cybex arm ergometer, and cybex fitron cycle ergometer were recorded for 19 stroke subjects and 19 control subjects matched by age and gender. Mean age in both groups was 66 years. There was no significant difference in the resting HR (controls: 69 +/- 10, patients: 70 +/- 11 beats per minute) and BP measurements (systolic--controls: 140 +/- 17, patients: 135 +/- 21; diastolic--controls 80 +/- 8, patients: 75 +/- 11mmHg). There was also no significant difference in either the mean HR (controls: 79 +/- 10, patients: 81 +/- 12 beats per minute) or BP (systolic--controls: 174 +/- 23, patients: 165 +/- 27; diastolic--controls: 98 +/- 15, patients: 92 +/- 14) response to exercise. With the arm ergometer test, the control group attained a significantly higher maximum systolic (190 +/- 23 mmHg) and diastolic blood pressure (102 +/- 15mmHg) than the stroke group (systolic 165 +/- 23; diastolic 91 +/- 10mmHg). During the leg ergometer exercise test, results were similar in both groups except that work completed was significantly higher for the control group (3592 +/- 1162kg) than for patients (2512 +/- 1348kg). None of the patients reported symptoms of dizziness, fainting, or chest pain. Prescribed exercise in stroke patients under supervision and within patient tolerance was found to be safe.

Activities of Daily Living↗
PubMed1988

Gardnerella vaginalis in the urinary tract: incidence and significance in a hospital population.

The significance of Gardnerella vaginalis in urine was studied by comparing urine culture results, urinalysis data, and clinical findings. Over a two-year period, G vaginalis was reported in 2.3% of all urine cultures. Of 72 patients with pure cultures (greater than 10(4) cfu/mL), 43 patients (59.7%) were found to have G vaginalis urinary tract infections. Furthermore, four of the infected patients had pyelonephritis. Symptoms associated with G vaginalis urinary tract infections varied, and pyuria was detected in only 58% of the cases. Conditions associated with G vaginalis urinary tract infection included a history of recurrent urinary tract infections and/or instrumentation and upper urinary tract disease.

Adolescent↗
PubMed1988

Acute epiglottitis: a different approach to management.

Between January 1979 and October 1986, 349 patients with epiglottitis were admitted to the Royal Children's Hospital, Melbourne, Australia. Forty-five (13%) patients were not intubated, 291 (83%) were managed by nasotracheal intubation and spontaneous respiration without sedation, three (1%) received continuous positive airway pressure, and ten (3%) were ventilated. The 294 patients who were not ventilated were intubated for a mean of 18 +/- 9.5 (SD) h; 90% were extubated within 24 h. Criteria for extubation included resolution of fever (less than 37.5 degrees C), passage of time (12 to 16 h), and improvement in the general appearance of the child. Laryngoscopy was not performed before extubation. Providing there is always a doctor present who can reintubate if accidental extubation occurs, routine use of sedation, paralysis and mechanical ventilation, and pre-extubation laryngoscopy are not required for the management of children with uncomplicated epiglottitis, and their use may prolong the period of intubation.

Acute Disease↗
PubMed1988

Exercise conditioning in the rehabilitation of patients with chronic obstructive pulmonary disease.

Fifty-nine patients with severe chronic obstructive pulmonary disease (COPD) performed pulmonary function and exercise tests before and after participation in a 12-day pulmonary rehabilitation inpatient program. Postdischarge follow-ups were performed at three months. Training consisted of twice daily aerobic exercise of 30 to 40 minutes' duration. Intensity of training was determined after exercise testing and approached the maximal limits of ventilation. In general, the program failed to demonstrate significant changes in pulmonary function. Exceptions were mid-expiratory flow rate (FEF25-75) (p less than .02) and peak flow rate (p less than .05). Evaluation of exercise capacity via maximal exercise testing yielded significant increases in caloric expenditure (p less than .001), peak exercise oxygen consumption (p less than .001), and work output (p less than .0001). Peak exercise ventilation increased significantly (p less than .005) due to an increase in tidal volume (p less than .002). Work efficiency improved with training, but the change was not statistically significant. Resting oxygen consumption and carbon dioxide production were decreased (p less than .05); tidal volume was increased (p less than .005). However, the significant increase noted in tidal volume did not alter minute ventilation. In general, the changes noted at 12 days were maintained at three months postdischarge. These data support the hypothesis that a short-term, in-hospital program of general exercise conditioning can improve work output, gas exchange, and mechanical efficiency without significantly affecting spirometric indices. These changes may translate into improved performance of activities of daily living and a sense of general well-being.

Efficiency↗
PubMed1988

Heterogeneity of serum creatine kinase isoenzyme MM in myocardial infarction: standardization of patterns by use of cord-blood serum.

We investigated serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in myocardial infarction, using isoelectric focusing in polyacrylamide gels. As many as 14 sub-band species were detected, and sequential sampling revealed a progressive anodal shift in their distribution. A nomenclature for sub-band typing is proposed. It denotes the major sub-bands as 1 (pl 6.91), 2 (pl 6.65), and 3 (pl 6.35); which are usually detected in sera of normal CK range. Abnormal sub-bands (associated with increases in the concentrations of CK) are denoted as a (pl 7.55), b (pl 7.35), c (pl 7.25), d (pl 7.05), e (pl 6.85), f (pl 6.72), g (pl 6.50), h (pl 6.40), i (pl 6.28), j (pl 6.20), and k (pl 6.15). Cord-blood sera gave highly reproducible CK-MM patterns characterized by prominent detection of sub-bands 1-3 and faint detection of c, e, f, g, h, i, and j. It is recommended as a standard for CK-MM sub-band typing.

Creatine Kinase↗
PubMed1987

Early postnatal development of the rat accessory olfactory bulb.

A volumetric study of the accessory olfactory bulb (AOB) in rats aged from birth (P0) to postnatal day 60 (P60) was conducted. AOB volume increased 600% from P0 to P18 and then declined, so that by P60, it was 66% of its maximum value. The growth of individual laminae paralleled overall AOB development, except for the internal plexiform layer, which continued to grow. The number of output neurons in the mitral cell layer declined after P18, while the total number of granule cells in the internal granular layer rose 300% from P0 to P18, but then did not change significantly through P60.

Aging↗