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Biomedical subjects

A Sparrow

Publications and source records attributed to A Sparrow.

8 recordsLinked to original sources

Management of cardiovascular disease risk factors in children. A national survey of primary care physicians.

A national survey of family physicians, general practitioners, and pediatricians revealed substantial physician differences in managing cardiovascular disease risk factors in children aged 2 to 18 years. Pediatricians tended to screen younger children but were more conservative in treatment. General practitioners tended to screen less and to initiate intervention in older children, but were more aggressive in therapy. While only 9% of surveyed physicians measured blood cholesterol levels routinely, 72% screened children with family histories of cardiovascular disease. The majority routinely measured blood pressure, but the ages of first measurements differed among physicians. Surprisingly, of those who had treated children with elevated blood pressure or blood cholesterol, 54% said that they had ever used antihypertensive and 12% used lipid-lowering drugs in children, including angiotensin converting enzyme inhibitors and clofibrate. Half the surveyed physicians felt prepared to provide dietary counseling, but only 14% felt successful with it. When asked what they considered were the major cardiovascular risk factors, less than one third of the physicians cited all three major factors: hypertension, hypercholesterolemia, and smoking.

Adolescent

Variation in venom proteins from isolated populations of tiger snakes (Notechis ater niger, N. scutatus) in South Australia.

Pooled venom of peninsula tiger snakes (Notechis ater niger) from 11 insular populations and one mainland area, and from a single population of the mainland tiger snake (N. scutatus) were subjected to SDS-PAGE and gel filtration chromatography. At least 20 proteins were resolved in the SDS-PAGE, some of which were common to all populations, but many others were highly variable. Elution profiles produced through gel filtration showed a clustering of some populations with like profiles, while others had distinctive patterns. Similarities and dissimilarities between each population venom profile were appraised. Variation in the venom patterns was independent of prey type or local ecology. Statistical analysis of the SDS-PAGE banding patterns suggests that grouping of populations was dependent on their relative geographic position and the time of isolation of each population from one another and the mainland population.

Animals

Natural history of asymptomatic carotid plaque.

In April 1981, a total of 297 carotid arteries were examined prospectively. All patients were asymptomatic and were referred to the peripheral vascular laboratory at Good Samaritan Medical Center, Phoenix, for real-time B-mode ultrasonography. A measurement of luminal area stenosis was determined to be either greater or less than 75%. In addition, the ultrasound echo pattern was used to classify plaque as either calcified, dense, or soft. If, for any reason, the patient or physician felt that carotid endarterectomy should be performed, the patient was dropped from the study. In addition, the use of antiplatelet medication or anticoagulants constituted disqualification. Three groups of patients were observed for three years or until symptoms became apparent. Patients in all three groups with stenosis greater than 75% at the time of initial study were at greater risk than their peers without significant narrowing; however, even those patients with less than 75% stenosis were at greater risk if the associated plaque was less organized, ie, soft. A definite trend toward higher risk is seen in plaques of lower density. Only 10% of those patients with calcified plaque and a significantly stenotic vessel have developed symptoms. In contrast, only three patients of the original 42 with soft plaque and a tight stenosis are still being observed. This study appears to confirm that soft plaques have a greater tendency toward subintimal hemorrhage, ulceration, or primary embolization than more well-organized plaques.

Arterial Occlusive Diseases

Existence of multiple forms of microsomal epoxide hydrolases with radically different substrate specificities.

Evidence for the existence in rat and rabbit liver of two microsomal epoxide hydrolases with radically different substrate specificities was obtained, one with a broad specificity (EHb), whilst the other catalyzed the hydrolysis of cholesterol 5 alpha,6 alpha-oxide (EHch), a reaction taken as diagnostic since it was not observed with pure fractions of EHb. The two enzymes were physically separated by immunoprecipitation using antibodies which had been raised against EHb purified to apparent homogeneity. The substrate specificity of the two enzymes is radically different and mutually complementary. Cholesterol 5 alpha,6 alpha-oxide has a trisubstituted oxirane ring. All epoxides of this nature tested to date were not, or very poor, substrates of EHb. The two enzymes can also effectively be discriminated by inhibitors, in that 5 alpha,6 alpha-imino-5 alpha-cholestane-3 beta-ol potently inhibits EHch but not EHb whilst 1,1,1-trichloropropene oxide has the opposite specificity. The cytosolic EH did not significantly contribute to the catalysis of the hydrolysis of cholesterol 5 alpha,6 alpha-oxide.

Animals