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Biomedical subjects

J Morrison

Publications and source records attributed to J Morrison.

276 records · Page 16Linked to original sources
PubMedDate not supplied

Effect of methylprednisolone on predicted myocardial infarction size in man.

Therapeutic manipulations designed to conserve myocardium in patients with acute myocardial infarction appear to improve prognosis. To assess the role of glucocorticoids given in pharmacologic dosage in the early treatment of patients with acute myocardial infarction, serial serum creatine phosphokinase (CPK) were obtained every 1-2 hours in 39 consecutive patients admitted with acute myocardial infarction. Determination of completed infarction size (ISc) was made using all available CPK values (range 70-160 hours). Predicted infarct size (ILp) was based on early data following the rise in CPK from baseline values: projected CPK values were obtained over a 160 hour period using a curve fitting procedure based upon nonlinear Gauss-Newton stepwise iterations. In 13 uncomplicated control patients ISp was 43.2 +/- 11.6 (mean +/- SE) CPK-gram-equivalents (CPK-q-eq), based on data from the first 7 hours following the rise in serum CPK, while ISc was 44.7 +/- 11.4 CPK-geq (r = .99, n = 13). In 7 additional control patients whose hospitals courses were complicated by clinical extension ISp was 71.8 +/- 18.0 CPK-g-eq while ISc was 118.6 +/- 31.0 CPK-g-eq (p less than .03). In 19 patients treated with 3 grams of methylprednisolone 7-14 hours following the rise in serum CPK from baseline, data from early CPK determinations (7 hours) indicated an ISp of 118.5 +/- 24.1 CPK-g-eq while total CPK data indicate an ISc of 89.6 +/- 13.2 CPK-g-Eq (p less than .04). The exponential clearance of CPK (kd) was approximated in the controls (kd = .00095 +/- .00007 min-1) and glucocorticoid treated patients (kd = .00099 +/- .00006 min-1) and found to be similar. Thus, administration of a pharmacologic dose of methylprednisolone 7-14 hours following rise in serum CPK from baseline in a group of patients with acute myocardial infarctions has resulted in salvage of myocardium.

Adult↗
PubMedDate not supplied

Studies on the venom of Oxyuranus microlepidotus.

The Australian Small-scaled Snake, Oxyuranus microlepidotus , recently rediscovered, is the world's most venomous snake, with a murine LD50 of 0.01 mg/kg. Recently developed immunological techniques, combined with a whole animal model, have enabled us to measure accurately the mass of venom actually injected by a striking snake. The venom of this species contains at least six identified protein fractions, and one or more of these possesses potent neurotoxic action. An initial assessment of the molecular weights of each of these is reported. This study describes field biting experiments applicable to potential human snake-bite, and presents data concerning the injected venom:LD50 ratio which is an index of potential human lethality. This snake delivers an average mass of 17.3 mg in a strike, and the injected mass:LD50 ratio is 1730, the highest recorded for any snake. Comparative results for five other Elapidae whose venom contains potent neurotoxins are also presented. An average mass of 0.6 mg of venom is split on the skin surface during a strike, and 40% of this can be recovered within three hours after a simulated bite. As with other Elapidae studied to date, an adequate mass of venom remains on the skin for an accurate species diagnosis to be made in the case of human snake-bite.

Animals↗
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Confidence boosters.

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Communicable Diseases↗
PubMedDate not supplied

Treatment of PAT. Bradycardiac reflexes induced by dive vs. body-tilt.

It has been suggested that the dive reflex (elicited by face immersion in water with breath-hold) may be employed to induce vagally-mediated bradycardia in individuals with paroxysmal atrial tachycardia. However, in several cases the use of this reflex is reported to have led to exacerbation of the cardiac dysfunction. Examination of heart-rate and EKG T-wave amplitude changes during the dive in healthy, college-aged individuals indicated that warming the water (10 degrees through 20 degrees C to 40 degrees C) decreased the bradycardia, but did not alter the attenuation (approximately 100 mu v) of the T-wave. The latter effect was taken to indicate that sympathetic activity, as indexed by T-wave amplitude, was not reduced by increases in water temperature. On the other hand, a 90 degrees head-up to head-down body tilt produced a bradycardia response of some 30 bpm as well as a T-wave amplitude increase (sympathetic withdrawal) in the order of 100 mu v. These data suggest that individuals who exhibit symptoms of ventricular sympathetic irritability may be adversely affected by the dive maneuver, regardless of water temperature. The body-tilt induced reflex in such individuals may thus be more appropriate given the large-magnitude bradycardia and absence of T-wave attenuation. At the present, however, the body-tilt preparation has been used only with healthy normal subjects, so this suggestion remains to be directly tested.

Adolescent↗