Search PubMed⌕ Search

Biomedical subjects

S R Williams

Publications and source records attributed to S R Williams.

At least 199 records · Page 11Linked to original sources
PubMed1981

Activity of phosphorylase in total global ischaemia in the rat heart. A phosphorus-31 nuclear-magnetic-resonance study.

1. The uptake and subsequent phosphorylation of deoxyglucose into perfused rat hearts was monitored by 31P n.m.r. 2. The accumulated deoxyglucose 6-phosphate provided (a) an independent method for measuring cytosolic pH in the normoxic and ischaemic heart tissue and (b) a way of studying the activity of phosphorylase during ischaemia. 3. The cytosolic pH measured from the 31P n.m.r. resonance position of deoxyglucose 6-phosphate is in good agreement under all conditions studied with that obtained previously from the Pi resonances. This eliminates any possible doubts about the use of Pi for measuring intracellular pH. 4. Deoxyglucose 6-phosphate in vitro inhibits phosphorylase b but not phosphorylase a. Its inhibitory effect on glycogenolysis during ischaemia is monitored by measuring tissue acidosis by n.m.r. In the initial stages of ischaemia phosphorylase activity is not inhibited, whereas after about 5 min approx. 50% of the activity is inhibited. These observations are interpreted in terms of the relative contributions of phosphorylase a and the AMP-dependent phosphorylase b activities during ischaemia.

Animals↗
PubMed1979

A case-control study of relationships of diet and other traits to colorectal cancer in American blacks.

Ninety-nine black colorectal cancer patients and 280 matched controls from hospitals and multiphasic health checkup clinics were interviewed about past dietary habits and other traits. The colon cancer cases tended to report less frequent use of foods with at least 0.5% fiber content than did their controls. This relationship, though small, showed a consistent dose-response gradient, appeared in both case-hospital control and case-multiphasic health checkup control comparisons, and could not be accounted for by the effects of other variables. Colon and rectosigmoid junction cancer patients tended to have eaten foods with at least 5% saturated fat somewhat more often than controls. When consumption of these two groups of foods was considered in combination, significantly more colon cancer patients than controls reported a high saturated fat foods-low fibrous foods eating pattern, as opposed to a low saturated fat foods-high fibrous foods diet. Statistically significant excesses of the following traits were also reported by the colorectal cancer patients: prolonged cigar smoking in men, nulliparity in women, and history of colorectal polyps.

Adenocarcinoma↗
PubMed1978

Phosphonoacetic acid in the treatment of simian varicella.

Phosphonoacetic acid inhibited replication of simian varicella virus (Delta herpesvirus) in tissue culture. The drug was tested in patas monkeys 40 h after infection with Delta herpesvirus. A total of 200 mg/kg per day was given intramuscularly, divided into two doses every day for a total of 10 days. The treated monkeys were protected from clinical illness, and Delta herpesvirus was not recovered from their lymphocytes. Complement-fixing and neutralizing antibody titers were significantly lower in phosphonoacetic acid-treated monkeys than in the untreated controls. In animals given the drug alone, there was dermatitis and blackening of the skin and hair, serum glutamic oxalacetic transaminase and serum glutamic pyruvic transaminase enzymes were significantly increased, and liver biopsy revealed diffuse cytoplasmic swelling and granulation of the hepatocytes. The therapeutic range of this drug should be studied carefully before considering its use in severe varicella-zoster infection in humans.

Animals↗
PubMed1975

The use of research in national health policy: an assessment and agenda.

This article provides an assessment of health services research contributions to national health policy. An examination of disciplinary-based research identifies many of the shortcomings of such research and the need for a different structure for relating research to health policy. Some definitions are offered for such terms as "applied research," "disciplinary research," "policy analysis," and "policy research." A policy research model of sequential steps in problem-solving is suggested as a useful approach. A review of the federal role in health policy is developed to set the context for viewing past contributions as well as to suggest a strategy for maximizing the relevance and usefulness of research.

Delivery of Health Care↗
PubMedDate not supplied

Controllable graded cerebral ischaemia in the gerbil: studies of cerebral blood flow and energy metabolism by hydrogen clearance and 31P NMR spectroscopy.

A technique for remotely controlling the degree of carotid artery occlusion in the gerbil model of cerebral ischaemia has been developed. The technique relies on manually adjustable nylon snares around the carotid arteries, in conjunction with a computer-based monitoring system, to control the degree of occlusion. This has allowed us to determine the dependence of energy metabolism (as assessed by 31P NMR spectroscopy) on blood flow in greater detail than was possible in our previous studies. Data obtained show that energy changes first appear at flows of 25-30 mL/100 g/min, while at flows below 20 mL/100 g/min there is a major derangement of energy metabolism. The model was used to determine the sensitivity of cerebral energy metabolism to reduced cerebral blood flow under normothermic conditions and in mild hypothermia (30 degrees C). Hypothermia had a protective effect in that energy metabolites were maintained at flows significantly below the normothermic threshold.

Adenosine Triphosphate↗
PubMedDate not supplied

Quantitative analysis of 1H NMR detected proteins in the rat cerebral cortex in vivo and in vitro.

Spectral editing experiments were used to quantify CH3 groups from macromolecular species in the chemical shift region from 1.2 to 1.4 ppm of rat cerebrum in vivo. Two peaks centred at 1.22 and 1.40 ppm were revealed when irradiation was positioned at 4.35 or 4.30 ppm. These peaks had lower saturation factors (1 vs. 1.72 +/- 0.10) than N-acetyl aspartate (NAA) and shorter T2 [60 +/- 5.8 (1.22 ppm) and 51 +/- 2.2 (1.40 ppm) vs. 123 +/- 12 (NAA) ms]. The concentrations of the peaks at 1.22 and 1.40 ppm were calculated to be 0.65 +/- 0.09 and 1.37 +/- 0.18 mmol of CH3 equivalents/kg brain. Acid extract from cerebral cortices contained macromolecular peaks at the same chemical shifts with approximately the same area ratios to NAA as in vivo. These data show that the macromolecular peaks in the brain at TE > 100 ms arise predominantly from proteins which are acid soluble. The assignment of macromolecular signals in the cerebral spectrum to a given polypeptide (thymosin beta 4 and histone H1) is discussed in the light of protein analyses of brain acid extracts.

Adenosine Triphosphate↗
PubMedDate not supplied

Tubeless anesthetic technique for optimal carbon dioxide laser surgery of the larynx.

PURPOSE: To evaluate the operative conditions and safety of a tubeless technique of anesthesia for carbon dioxide laser surgery of the larynx. MATERIALS AND METHODS: This prospective study evaluated 78 consecutive procedures in 72 adult patients undergoing carbon dioxide laser microlaryngeal surgery. Anesthesia was maintained by an intravenous infusion of Propofol (ICI Pharmaceuticals, Cheshire, UK) while the patient breathed spontaneously without endotracheal intubation. RESULTS: The operative conditions were optimal in 76 of the 78 procedures providing a clear uninterrupted view of the larynx with no combustible material in the surgical field. CONCLUSIONS: This series shows the technique described to be safe without risk of combustion and provides an unobstructed view to the larynx.

Adolescent↗
PubMedDate not supplied

Prehospital use of activated charcoal: a pilot study.

Activated charcoal (AC) is most effective when administered soon after the ingestion of certain substances. Delays are recognized to occur at times in the administration of AC after arrival of poisoned patients in the emergency department (ED). In addition, it has been recognized that these delays may be avoided if AC administration is begun in selected patients by paramedics while en route to the ED. We present a pilot study evaluating the administration of AC to poisoned patients in the ambulance prior to arrival in the ED. We performed a retrospective review of Emergency Medical System (EMS) run sheets and ED records of poisoned patients during a 6-month period from two area hospitals. Cases were identified that met criteria for the prehospital administration of AC. Cases were divided into two groups: those who received prehospital AC, and those who did not. Groups were compared for ambulance transport time, time from first paramedic contact to AC administration, and whether AC was tolerated by the patient. A total of 14 patients received prehospital AC (group 1). This group was compared to 22 cases that would have qualified under County protocol to receive prehospital AC, but for whatever reason did not (group 2). Group 2 patients all received AC after arriving in the ED. Average ambulance transport times did not statistically differ among groups. The average time from first encounter with paramedics to administration of AC was 5.0 minutes when AC administration was given in the ambulance as compared to 51.4 minutes when delayed until arrival in the ED. Tolerance was similar among the groups. The time to initiate AC administration may be significantly shortened when begun by prehospital personnel. All EMS should consider including AC in protocols addressing the prehospital management of certain poisoned patients.

Ambulances↗
PubMedDate not supplied

Refining the level for anticipated hepatotoxicity in acetaminophen poisoning.

Treatment of an acetaminophen overdose with N-acetyl cysteine usually is based on the position of the 4-h acetaminophen (APAP) level on the Rumack-Matthew nomogram; however, there is disagreement on the level at which clinically relevant hepatotoxicity occurs. A retrospective review of all acute adult formulation APAP exposures reported to our poison center between 1986 and 1993 was performed and cases corresponding to the "possible risk or toxicity" range on the nomogram were identified. Our current poison center protocol for APAP poisoning does not recommend treatment with N-acetylcysteine (NAC) in low-risk patients if the 4-h serum APAP level or the extrapolated equivalent falls within the possible toxicity range on the nomogram. Seventeen cases met the inclusion criteria for the study and received no NAC; six additional patients met inclusion criteria but received one or two doses of NAC before therapy was discontinued. No patients in either group demonstrated clinical evidence of hepatotoxicity. This pilot study suggests that patients with no risk factors and APAP levels in the "possible risk" range may not require NAC therapy.

Acetaminophen↗
PubMedDate not supplied

Ethylene glycol poisoning: case report of a record-high level and a review.

Ethylene glycol is commonly found in automobile antifreeze and a variety of other commercial products. Ingestion of ethylene glycol, either accidentally or in a suicide attempt, is characterized by severe acidosis, calcium oxalate crystal formation and deposition, and a wide variety of end organ effects that may be fatal. We present a case of a patient who ingested a massive amount of ethylene glycol in a suicide attempt and yet survived with minimal sequelae. A comprehensive review of the literature on the pathology and pathophysiology of ethylene glycol toxicity on each organ system is provided, along with information on diagnosis and current treatment recommendations.

Adult↗