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Biomedical subjects

S Mills

Publications and source records attributed to S Mills.

84 records · Page 5Linked to original sources
PubMed1983

Stimulation of calcium uptake by parathyroid hormone in renal brush-border membrane vesicles. Relationship to membrane phosphorylation.

The effect of parathyroid hormone (PTH) on Ca2+ uptake was studied in brush-border membrane vesicles (BBMV) prepared from the kidneys of dogs administered 4-5 micrograms/kg of bovine PTH 1-84 in vivo. PTH stimulated Ca2+ uptake at 20 s of incubation from control values of 231 +/- 21 to 306 +/- 30 pmol/mg of protein, p less than 0.001. The stimulation of Ca2+ uptake by PTH was not reversed by incubation of the BBMV with the Ca2+ ionophore, despite the fact that Ca2+ uptake was several times greater than the expected uptake at equilibrium, indicating that most of the uptake represented Ca2+ binding to the BBMV. In BBMV from kidneys exposed to PTH, hypotonic lysis or increasing the osmolality of the solution external to the BBMV did not affect Ca2+ uptake. These data also indicated that the largest fraction of Ca2+ uptake in the presence of a chemical potential represented binding of Ca2+ to BBMV. Ca2+ binding was initially to the exterior of the BBMV, then translocated within the membrane and to the interior vesicular face as assessed by chelation of Ca2+ bound to the BBMV by ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. Incubation of BBMV from kidneys exposed to PTH with gentamicin, which competes with Ca2+ for anionic phospholipid-binding sites, reversed the stimulatory effects of PTH on Ca2+ uptake. Phosphorylation of BBMV and PTH treatment in vivo had similar effects on BBMV phospholipid composition increasing the levels of anionic phospholipids. Phosphorylation of the BBMV also produced gentamicin-inhibitable increases in membrane Ca2+ binding. Phosphorylation of BBMV from kidneys exposed to PTH was inhibited suggesting a higher state of phosphorylation in vivo. The data demonstrate that PTH administered in vivo stimulated Ca2+ binding in BBMV that was gentamicin inhibitable and associated with an increase in the membrane content of anionic phospholipids.

Animals↗
PubMed1975

Detection of particles in intravenous fluids using scanning electron microscopy.

A study was conducted to compare the particles in intravenous solutions found in glass and plastic containers, and to investigate the use of scanning electron microscopy in detecting and identifying such particulate contamination. The method used was to filter one liter of each fluid from glass and plastic containers through a membrane filter, attach the membrane to aluminum studs and coat the specimens with a thin layer of gold-palladium in a vacuum evaporator. Scanning electron microscopy was then used to examine the specimens, and photomicrographs were prepared. The results showed that the particles found in glass and in plastic containers have distinctive differences and that scanning electron microscopy is useful in detecting and characterizing these particles.

Drug Contamination↗
PubMedDate not supplied

Endogenous opioids and opiate antagonists modulate the blood pressure of the spontaneously hypertensive rat.

Endogenous opioids have been implicated as modulators of the central nervous system regulation of blood pressure and heart rate. Whether these neuropeptides participate in blood pressure regulation in hypertension is unknown. To begin to study this question, we examined the response to opiate antagonists and agonists in the spontaneously hypertensive rat (SHR) and the normotensive Wistar-Kyoto (WKY) rat. The long-acting opiate antagonist naltrexone, 2.5 micrograms/kg, was injected into the lateral ventricle of the brain in awake, freely-moving SHR and produced a significant 19 mmHg decrease in mean arterial blood pressure compared to basal blood pressure (p less than 0.01); a decrease was not observed at a two logarithm lower dose. In contrast, naltrexone had no effect on the blood pressure of normotensive Wistar-Kyoto (WKY) rats. To evaluate a possible regulatory role for the predominantly kappa receptor active opioids, alpha- and beta-neo-endorphin, 10 micrograms each, was administered to SHR on separate days by intracerebroventricular injection. alpha- and beta-neo-endorphin caused significant decreases in mean arterial blood pressure of 11 and 9 mmHg respectively, effects reversed by pre-treatment with the opiate antagonist, naloxone. Heart rate was unaffected by any of the injected opioids or antagonists. Our naltrexone results support the hypothesis that an endogenous opioid(s) contributes to the hypertensive state of the SHR. Additionally, alpha- and beta-neo-endorphin can lower blood pressure in this model.

Animals↗
PubMedDate not supplied

Evaluation of the 1990 Centers for Disease Control and Prevention smoke-free policy.

PURPOSE: To determine the prevalence of tobacco use among Centers for Disease Control and Prevention (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR) employees and the effect of the smoke-free policy on smoking behavior and air quality at work. DESIGN: A stratified telephone survey of 1181 CDC/ATSDR employees randomly selected from employee rosters. SETTING: CDC/ATSDR work sites in Atlanta, Georgia, and other major CDC locations throughout the United States and Puerto Rico. SUBJECTS: Randomly selected employees of CDC/ATSDR1, or about 22% of the total CDC/ATSDR population; 98% of eligible persons selected agreed to participate. MEASURES: Demographic and smoking history variables, attitudes toward and impact of the smoke-free policy on smoking behavior, and self-report changes in air quality were the measures used. RESULTS: Overall cigarette smoking prevalence was only 11.1%. One percent reported using chewing tobacco, 1.1% reported smoking a pipe, and 1.4% reported smoking cigars. Average self-reported, daily cigarette consumption significantly decreased after the smoking ban took effect. Overall, 90% of the employees supported the smoke-free policy, and 80% of the employees believed that smokers were complying with the smoke-free policy. Most employees believed that the air quality of work areas and nonwork areas (65% and 69%, respectively) had improved since the smoke-free policy was implemented. CONCLUSIONS: These findings are consistent with previous evaluations of smoke-free policies and suggest that most employees are generally supportive of workplace smoking restrictions. Such policies can also have a positive impact on smoking behavior and perceived air quality.

Adolescent↗
PubMedDate not supplied

A practical approach to improving the quality of water used for routine dental treatments.

The water delivered through dental units connected to municipal water supplies often is contaminated with bacteria and other organisms as a result of biofilm formation in waterlines. Water and other solutions used for dental treatment should meet generally recognized standards for drinking water quality. Public concern over the safety of drinking water and media attention paid to dental water quality will continue to increase. The number of immunocompromised patients who are at risk of developing infectious diseases from exposure to contaminated water aerosolized from dental units also will continue to increase. Improving the quality of water used in routine dental treatment is a worthwhile goal and reasonable measures to improve water quality now are available.

Aerosols↗