Search PubMed⌕ Search

Biomedical subjects

R L Williams

Publications and source records attributed to R L Williams.

At least 343 records · Page 19Linked to original sources
PubMed1978

Nocturnal penile tumescence and diagnosis in diabetic impotence.

The authors conducted a study of nocturnal penile tumescence (NPT) in 35 diabetic men, aged 33 to 70, who complained of impotence and in 35 age-matched control subjects. EEGs and other measurements showed that the diabetic men as a group exhibited significant reductions in the total amount of NPT and in the amount and frequency of full erection, thus suggesting that impotence in this cohort was organogenic. Although NPT monitoring represents an advance over the less precise traditional procedures for the differential diagnosis of impotence, the authors stress the need for more research in this area.

Adult↗
PubMed1978

The influence of acetylator phenotype on the response to sulfalene in individuals with chloroquine-resistant falciparum malaria.

The disposition of sulfalene was studied in eight individuals before and during an infection with a chloroquine-resistant strain of Plasmodium falciparum. Isoniazid acetylator phenotype was determined in each individual prior to the administration of sulfalene. Following the administration of sulfalene before infection with malaria, a significant difference in half-life of non-acetylated sulfalene and percent acetylation of sulfalene in plasma was observed between rapid and slow acetylators. When sulfalene was administered during malaria, this difference was no longer apparent. Individuals who did not respond to the therapeutic administration of sulfalene alone were treated with a combination of sulfalene and pyrimethamine. Three individuals were cured by sulfalene without pyrimethamine and one was cured by the drug combination. Three of the four individuals who were not cured by any dose of sulfalene or the drug combination were slow acetylators. There was no distinct correlation between clinical response and maximum levels or half-life of nonacetylated sulfalene. These findings suggest that acetylator phenotype does not influence the therapeutic response of individuals infected with falciparum malaria to sulfalene or to the combination of sulfalene and pyrimethamine. Further information is presented, however, to confirm the importance of an as yet unidentified host factor(s) in determining therapeutic response to these agents.

Acetylation↗
PubMed1978

Effects of high ambient temperature on sleep in young men.

Each of 10 normal subjects had 4 nights of laboratory-monitored sleep, consisting of adjustment, baseline, high blanket temperature (HBT), and recovery nights. EEG-EOG recordings were made on each night; rectal temperature, heart rate, body weight, and ambient temperatures were monitored throughout the last 2 nights. On the HBT night, subjects had less total sleep time, more frequent and longer awakenings, greater shifting among sleep stages, decreased amounts of stage 1 REM and stages 3 + 4, and delayed onset of deep sleep (stages 3 and 4). Body temperature was elevated to a relatively constant level of 37 degrees C on the HBT night, but gradually decreased from 36 degrees C to 34.5 degrees C across the recovery night. Heart rate decreased at a linear rate on both the HBT and recovery nights, but was 15 beats/min faster on the former. Subjects experienced liquid loss of 1.25 kg on the HBT night, but had a full recovery by the following evening.

Adult↗
PubMed1977

DiGeorge syndrome presenting as severe congenital heart disease in the newborn.

In seven infants with DiGeorge syndrome the major clinical manifestation was cardiac failure in the 1st week of life. All had severe congenital heart disease: five had interruption of the aortic arch and associated lesions, one had a ventricular septal defect and a cervical aorta, and one had truncus arteriosus. All but one died by 2 weeks of age. Necropsy data lent support to the hypothesis of a relation between the cardiovascular anomalies and defective development of structures derived from the third and fourth pharyngeal pouches.

Aorta, Thoracic↗
PubMed1977

Alteration of ovine fetal respiratory-like activity by diazepam, caffeine, and doxapram.

The effects of diazepam, caffeine citrate, and doxapram on fetal respiratory-like activity (RLA) were studied in 10 chronic sheep preparations (90 to 130 days' gestation). We define fetal RLA as regular changes in fetal tracheal pressure occurring with a frequency of at least 1 Hz and an amplitude greater than -5 mm. Hg in the absence of fluctuations in amniotic cavity pressure. In all maternal (8) and fetal (7) intravenous infusions of diazepam (5 to 10 mg.), RLA ceased almost instantaneously. The duration of fetal apnea varied from 29 to 70 minutes with a mean of 57 minutes, and on occasion, a gasping pattern preceded recovery of RLA. Maternal and fetal plasma concentrations of diazepam indicated rapid bidirectional placental transfer. Intravenous infusion of doxapram (3 mg.) to the fetus immediately initiated a transient episode of RLA in 19 of 20 trials. Fetal infusion of caffeine citrate (10 to 20 mg.), especially via the carotid artery, was also associated with the rapid onset of a transient episode of fetal breathing. Saline control infusions were without effect. Fetal blood gases and pH were not altered by the administration of diazepam, caffeine citrate, or doxapram. It is suggested that each drug owes its action on RLA to an effect on fetal central nervous system. The influence of pharmacologic agents on the process and interpretation of fetal monitoring requires continued attention.

Animals↗
PubMed1977

Influence of acute viral hepatitis on disposition and plasma binding of tolbutamide.

To study the influence of acute hepatic disease on the disposition of tolbutamide, we measured tolbutamide plasma protein binding and pharmacokinetic parameters after intravenous administration of the drug to 5 subjects during and after apparent recovery from acute viral hepatitis. Although during the acute phase of illness protein binding of the drug decreased in all, volume of distribution of tolbutamide (0.15 +/- 0.03 L/kg) did not change. Clearance based on total concentration of tolbutamide in plasma increased in all subjects during the acute phase of study (26 +/- 5.4 ml/hr/kg) in comparison to the recovery phase (18 +/- 2.8 ml/hr/kg, p less than 0.02). Protein binding decreased after unconjugated bilirubin was added to plasma from the recovery phase, but not to the extent observed during the acute phase of illness at comparable levels of bilirubin. Clearance based on unbound drug concentration, calculated by dividing the observed plasma clearance by the fraction of unbound drug in plasma, did not differ significantly between the 2 study phases (300 +/- 47 and 260 +/- 39 ml/hr/kg). These observations suggest that the increase in clearance based on total drug concentration in plasma during hepatitis can be attributed solely to decreased plasma binding. This decrease in binding may be attributed in part, but not entirely, to increased combination of bilirubin during illness. The concentration of unbound drug in plasma at steady-state is determined by the rate of drug administration and the clearance based on unbound drug. If this clearance does not change during hepatic disease, no dosage alterations for tolbutamide and other comparable drugs are necessary to maintain a constant concentration of unbound drug.

Acute Disease↗
PubMed1977

Application of salivary concentration data to pharmacokinetic studies with antipyrine.

The concentrations of antipyrine in plasma and saliva were equivalent in normal volunteers and in patients with acute viral hepatitis following oral doses of antipyrine. Estimates of clearance, volume of distribution, and half-life made from either plasma or saliva samples were not statistically different in these subjects. Differences in the disposition kinetics of anticted using either plasma or saliva samples.

Acute Disease↗
PubMed1977

Sleep disorders.

Explore the source record for details and available documents.

Animals↗
PubMed1977

Nocturnal erections, differential diagnosis of impotence, and diabetes.

In this study it is shown that monitoring of nocturnal penile tumescence (NPT) is an objective method for determining the erectile status of patients who complain of impotence. The characteristics of 11 diabetic patients with abnormal NPT, 11 patients with normal NPT and no medical disorders, and 11 normal men are presented. Also described are several sociodemographic characteristics of the first 100 patients undergoing an NPT evaluation as part of a screen for patients seeking implantation of a penile prosthesis. It is suggested that NPT monitoring should be a component of the differential diagnosis procedure for every patient who complains of impotence and that it provides a tool for the concentrated study of the mechanisms of erection and impotence.

Adult↗
PubMed1976

Quinine disposition during malaria and during induced fever.

Quinine disposition was studied in 5 subjects before and during an experimentally induced infection with a chloroquine-resistant strain of Plasmodium falciparum and in 2 individuals before and during artificially induced fever. Plasma quinine levels were determined by both a benzene extraction method (QB), which measures principally unmetabolized quinine, and a metaphosphoric acid precipitation method (QMPA), which measures quinine and quinine metabolites. The ratio QB/QMPA in plasma was used to estimate the extent of metabolism of quinine. In all individuals plasma levels of quinien and QB/QMPA ratios were increased during malaria, suggesting impaired hepatic metabolism of quinine. The changes observed during malaria were not due to altered renal excretion of quinine. In 2 subjects in whom fever was artificially induced there were similar changes in quinine metabolism. These observations suggest that quinine dosage should be modified during the initial period of treatment, when symptoms and fever are greatest, in acute falciparum malaria.

Erythrocytes↗
PubMed1976

Influence of acute viral hepatitis on disposition and pharmacologic effect of warfarin.

Five patients received a small oral dose of warfarin during and after recovery from acute viral hepatitis. Mean (+/- SD) clearance, volume of distribution, and half-life of the drug were 6.1 +/- 0.9 ml/hr/kg, 0.09 +/- 0.04 L/kg, and 23 +/- 5 hr, respectively, during the acute period. After apparent recovery, observed values were 6.1 +/- 0.7 ml/hr/kg, 0.21 +/- 0.02 L/kg, and 25 +/- 3 hr. These differences were not significant. Pattern of renal elimination of warfarin metabolites and drug protein binding did not change between the two phases. During the acute period of illness, prothrombin time increased in 2 of the 5 subjects, but remained within normal limits in all participants during the recovery period. This study shows that warfarin disposition may not change as a consequence of mild or moderate hepatic impairment.

Adult↗
PubMed1976

Influence of viral hepatitis on the disposition of two compounds with high hepatic clearance: lidocaine and indocyanine green.

The disposition of lidocaine and indocyanine green was studied in 6 individuals during and after recovery from an episode of acute viral hepatitis. Both compounds are highly cleared from the blood by the liver so that clearance of both should be sensitive to changes in hepatic blood flow. During the acute phase of illness, clearance of indocyanine green decreased without apparent change in volume of distribution, whereas clearance of lidocaine, decreased in 4, did not change in 1, and increased in 1 during the acute phase of hepatitis. Volume changes for lidocaine were also variable. We observed no significant correlation between any parameters of lidocaine disposition and any of several tests of liver function or any parameters of indocyanine green disposition. The absence of correlation between pharmacokinetic parameters of the disposition of lidocaine and indocyanine green indicates that the influence of hepatic disease on the hepatic processes that lead to the elimination of each compound is not predictable. No useful clinical correlates are now available by means of which to predict lidocaine disposition in patients with altered hepatic function.

Acute Disease↗