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Biomedical subjects

E Boyle

Publications and source records attributed to E Boyle.

At least 19 recordsLinked to original sources
PubMed1996

Monoglycerides in membrane systems.

Monoglycerides are used abundantly in food systems, ingested and produced in vivo, and recognized as significant mediators in many biochemical processes, yet their function in various membrane systems is only understood at a hypothetical level. This paper provides a comprehensive review of the effects of monoglycerides in membrane systems from three diverse disciplines: nutrition, food science, and membrane biochemistry. An analysis of the data ranging from feeding studies to physical chemistry is given, detailing the role of these common molecules in biological membranes.

Chylomicrons↗
PubMed1996

Monoacylglycerols alter the lipid composition and molecular mobility of phosphatidylcholine bilayers: 13C NMR evidence of dynamic lipid remodeling.

The physical effects of monoacylglycerols (MAG) in small unilamellar vesicles composed of phosphatidyl-choline (PC), triolein, cholesterol, and varying amounts of monopalmitin and monoolein were studied by 13C-NMR. The signal to noise ratio of the carbonyls of PC and triolein were enhanced by the addition of 1,2-di-[1-13C]palmitoylphosphatidylcholine and tri-[1-13C]oleoylglycerol. The linewidths of the carbonyl-13C, choline methyl, olefinic carbon, and terminal methyl resonances were measured digitally from vesicles with 0 to 42 mol % of MAG. Significant increases in the linewidth of carbonyl (P < 0.05), olefinic and terminal methyl carbons (P < 0.01) of vesicles containing 42 mol % monopalmitin indicated that these groups experienced restricted molecular mobility at high monopalmitin concentrations. However, more striking was the apparent displacement of triolein from the surface environment of PC bilayers to an oil-like environment in systems containing only 8 mol % monopalmitin. Displacement of triolein from the surface by monoolein occurred only above 15 mol %. Thus, saturated and monounsaturated monoacylglycerols, natural products of lipoprotein metabolism, dynamically alter both the lipid composition and molecular mobility of lipoprotein surfaces in distinct ways.

Chemical Phenomena↗
PubMed1995

Injury prevention strategies to promote helmet use decrease severe head injuries at a level I trauma center.

Head injuries (HIs) remain a major contributor to trauma mortality, with many deaths occurring despite optimal use of available therapy. Injury prevention is vital to decrease the impact of HIs. Helmets can decrease the severity of HIs in both bicycle crashes (BCs) and motorcycle crashes (MCCs). A major challenge is to increase helmet use. A mandatory motorcycle helmet law in 1990 and information campaigns aimed at bicyclists have increased the percentage of riders wearing helmets in Washington State. We hypothesized that there would be an associated decrease in the proportion of severe HIs in BC and MCC admissions to the state's only level I trauma center. We analyzed injury region and outcomes for all 466 BC and 992 MCC instate admissions from 1986 to 1993. For BCs, the proportion of severe HIs (Abbreviated Injury Scale score of 4 or 5) declined from 29% in 1986 to 11% in 1993 (p = 0.02). BC trends paralleled helmet use in observations on 8,860 bicycle riders in the area, in which the percentage of helmeted riders rose from 5% in 1987 to 62% in 1993 (p < 0.001). For MCCs, severe HIs declined from 20% before passage of the helmet law to 9% afterward (p < 0.001). Mortality decreased for BCs and MCCs (p < 0.05), and length of hospital stay and ICU stay decreased for BCs (p < 0.05). The percentage of helmeted BC admissions rose from 0% to 32% (p = 0.009), and helmeted MCC admissions rose from 41% to 80% (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1994

Choline acetyltransferase activity of rat synaptosomes is sensitive to enflurane, but not halothane or isoflurane.

We have examined the activity of choline acetyltransferase (ChAT) in rat cortical synaptosomes in the presence of three volatile anaesthetic agents: enflurane, halothane and isoflurane. The Michaelis constant Km, for choline was reduced significantly (P = 0.012) in the presence of 6.5% enflurane (3 rat MAC) compared with control samples exposed to carrier air only, while maximum reaction velocity (Vmax) remained unaltered. The reduction in Km was also significant at enflurane concentrations of 4.4% (2 rat MAC) (P = 0.043) and 2.2% (1 rat MAC) (P = 0.043). Halothane 3% (2.5 rat MAC) and 4.5% isoflurane (3 rat MAC) had no effect on either kinetic property. If present in vivo, an enflurane-induced alteration in acetylcholine metabolism, through modified ChAT, may contribute to the convulsive properties of this anaesthetic.

Anesthetics↗
PubMed1994

Volatile anesthetic agents inhibit choline uptake into rat synaptosomes.

BACKGROUND: Acetylcholine is an excitatory neurotransmitter associated with the maintenance of consciousness. Choline uptake is the rate-limiting step in acetylcholine synthesis and may be a target for the action of volatile anesthetic agents. METHODS: [Methyl-3H]choline uptake was investigated using rat cortical synaptosomes. The preparation was exposed to air, as control, or equipotent partial pressures (2.4 rat MAC) of enflurane, halothane or isoflurane. In addition, the dose-response relation for halothane on [methyl-3H]choline uptake was studied. RESULTS: The maximum rate of uptake was reduced significantly by 24% in the presence of enflurane (5.5%, 2.4 rat MAC) and isoflurane (3.5%, 2.4 rat MAC) and by 38% in the presence of halothane (3%, 2.4 rat MAC) with no change in Michaelis constant in the presence of each agent. A linear relation between the inhibition of [methyl-3H]choline uptake and the concentration of halothane was observed up to 3% halothane above which there was no further inhibition. The concentration of halothane resulting in half-maximum inhibition of total choline uptake was 1.5%. CONCLUSIONS: Noncompetitive inhibition of [methyl-3H]choline uptake by volatile anesthetic agents has been demonstrated in the in vitro synaptosome preparation. If present in vivo reduction in anesthetic-sensitive choline uptake may reduce the presynaptic availability of acetylcholine and hence contribute to the process of anesthesia.

Anesthetics↗
PubMed1994

Assessment of the validity of the INR system for patients with liver impairment.

The INR system was developed to standardize PT reporting in patients on oral anticoagulants. We prospectively collected blood samples from 29 patients with liver impairment (INR 1.5-3.5). Control patients were on warfarin (n = 31). PT's were measured on an ACL-300 with three thromboplastin reagents. INR's were calculated using instrument specific ISI's. Other tests performed were FDP's, fibrinogen, aPTT, factors II, V, VII and X. The INR's for each patient in the study population using the three thromboplastin reagents were significantly different (p = 0.0001). Those for the control population were not (p = 0.0658). Fibrinogen, factors V, II and X were different at the 5% level of significance between the populations. FDP's were detected in 17 study subjects. The INR system is not valid for comparison of patients with liver impairment because different reagents do not give the same INR for the same sample. It is, however, no less valid than the use of PT with different thromboplastin reagents. Further study is recommended.

Adult↗
PubMed1992

The Human Communication Research Centre dialogue database.

The HCRC dialogue database consists of over 700 transcribed and coded dialogues from pairs of speakers aged from seven to fourteen. The speakers are recorded while tackling co-operative problem-solving tasks and the same pairs of speakers are recorded over two years tackling 10 different versions of our two tasks. In addition there are over 200 dialogues recorded between pairs of undergraduate speakers engaged on versions of the same tasks. Access to the database, and to its accompanying custom-built search software, is available electronically over the JANET system by contacting liz@psy.glasgow.ac.uk, from whom further information about the database and a user's guide to the database can be obtained.

Adolescent↗
PubMed1984

Incidence of coronary heart disease in blacks in Charleston, South Carolina.

We studied a cohort of 2275 blacks and whites of both sexes in Charleston County, South Carolina, during the period of 1960-1961 to 1974-1975. There were 93 prevalent cases of coronary heart disease (CHD) at intake, and 317 new cases occurred by 1975 in persons originally free of CHD. White males had the highest incidence rates for all types of CHD and acute myocardial infarction (AMI). Black males and black females had the next highest rates. The incidence of angina pectoris in black females was double the rate in white females and five times the rate in white males. The rate of sudden death in black males was two and one-half times the rate in black females, three times the rate in white males, and four times the rate in white females. One hundred and one black males who had been selected on the basis of high socioeconomic status (SES) had AMI and CHD rates half that of other black males. None of the high SES black males experienced angina pectoris, AMI death, or sudden death during the observation period.

Adult↗
PubMed1981

Skin color and education effects on blood pressure.

This study reports that education effects but not skin color effects were associated with blood pressure and the incidence of hypertension in a cohort of Black females in Charleston, South Carolina, observed over the period 1960-1975. The authors suggest that skin color may be a secondary (non-causal) associate of blood pressure in Blacks.

Adult↗
PubMed1980

The histology and collagen content of cotton pellet and polyvinyl sponge-induced granulomas in normal and drug-treated rats.

Comparison of cotton wool and sponge-induced granulomas in the rat showed that collagen contents were very similar despite the different pattern of granuloma formation. There was significantly less variation of individual results in the sponge. Although collagen accounted for less than 10% of the dry weight, there was a positive correlation between the 2 parameters in both models of 9 days but only in the pellet at 15 days. Hydrocortisone treatment significantly decreased dry weight and collagen content. There was rapid cell proliferation and collagen synthesis in the sponge granuloma from Day 5, reaching a peak between the ninth and twelfth day, when DNA levels dropped and collagen increased more slowly to plateau by Day 15. Day 9 was chosen as the most suitable stage to study drug effects. Dexamethasone significantly decreased collagen synthesis whereas indomethacin and phenylbutazone did not. Soluble collagen levels were increased with beta-amino-propionitrile and d-penicillamine; a dose-related effect was obtained with d-penicillamine.

Aminopropionitrile↗
PubMed1977

Cyclocryotherapy: a light and electron microscopic study.

Previous anatomic studies of the effects of cyclocryotherapy have produced confusing results because of variations in technique and instrumentation. Five eyes from three patients treated by a standard technique were compared to the eyes of rhesus monkeys that received identical treatment. The monkeys were given horseradish peroxidase intravenously 30 minutes before enucleation. Hemorrhage, edema, and epithelial disruption were characteristic of the acute lesions. Later, the nonpigmented ciliary epithelium disappeared, but by two months, normal morphology was restored. Normal peroxidase flow reappeared at a similar time. Anatomic changes in the human and monkey eyes were similar.

Animals↗
PubMed1977

Chromium depletion in the pathogenesis of diabetes and atherosclerosis.

Dietary Cr deficiency may cause the aging-related Cr depletion observed in humans. Such depletion, when it occurs with excessive consumption of sugar and other carbohydrates, may result in glucose intolerance, glycosuria, hyperinsulinemia, and hyperlipidemia. These metabolic disorders could explain why athero-sclerotic diseases are endemic to most Western industrial societies. This review detailed significant current research and findings on the manifestations of Cr deficiency in humans and animal models.

Animals↗
PubMed1977

Hypertension: effects of social class and racial admixture: the results of a cohort study in the black population of Charleston, South Carolina.

It has been hypothesized that genetic factors, as manifested by skin color, play in important role in the genesis of hypertension among Blacks. A community-based study was carried out in Charleston Country, South Carolina to test this hypothesis. The results of a ten year follow-up study suggest that social class and age were more consistently associated with the incidence of hypertension and levels of blood pressure. The association of hypertension with skin color was minimal and substantially less than that of social class. The incidence rate of hypertension (larger than or equal to 90 mm Hg) was three to four times greater when the study participants were of low social class than when they had higher social class scores at the beginning of this study. In contrast, the incidence rate was only 1.5 times higher for dark than for lighter skinned men, and the rates were almost identical when social class was comparable. Similar results energed when blood pressure was treated as a continuous variable; blood pressure levels and pressure changes over time were consistently and significantly (p less than .01) higher in those Blacks categorized as low social class, controlling for skin color.

Adult↗
PubMed1976

The role of copper in preventing gastrointestinal damage by acidic anti-inflammatory drugs.

The ability of several non-steroidal acidic anti-inflammatory drugs to cause ulceration when given as copper complexes has been examined. The damage caused by clopirac, niflumic acid and aspirin was virtually abolished when they were given as copper complexes whereas the damage caused by indomethacin, ketoprofen and (+)-naproxen was unaltered. The lack of ulceration with three of these preparations appeared to be correlated with a much reduced ability to inhibit prostaglandin synthesis as determined using an in vitro enzyme system.

Acetates↗