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Biomedical subjects

M Henderson

Publications and source records attributed to M Henderson.

At least 127 records · Page 7Linked to original sources

Acute coronary artery occlusion during percutaneous transluminal coronary angioplasty treated by redilation of the occluded segment.

Acute occlusion of a coronary artery during percutaneous coronary angioplasty usually results in unremitting ischemia requiring emergency surgical intervention. Seven patients are described, in whom complete occlusion occurred during coronary angioplasty as a result of coronary artery dissection. Despite this, it was possible to reintroduce the balloon catheter immediately and redilate the vessel with abrupt reversal of clinical and electrocardiographic manifestations of ischemia. Six patients had no subsequent evidence of myocardial infarction. The seventh had a slight elevation of serum creatine kinase and transient electrocardiographic changes. All patients were discharged from the hospital without further intervention. Four patients had elective coronary artery bypass surgery (greater than 4 weeks after angioplasty) and three have remained asymptomatic or in improved condition since the coronary angioplasty. It is concluded that sudden occlusion of a coronary artery during coronary angioplasty can be safely treated by redilation in the acute stage.

Acute Disease↗

Converting-enzyme inhibition and 1-sarcosine-8-isoleucine-angiotensin II: effects on renal function in the dehydrated sheep.

The effect of a converting-enzyme inhibitor (captopril) was studied in nine conscious dehydrated Merino ewes. Captopril (4 mg I.V. over 40 min) caused significant decreases in mean arterial blood pressure (M.A.B.P.), renal vascular resistance (R.V.R.) and filtration fraction, and increases in urine flow (V), sodium excretion, glomerular filtration rate (G.F.R.), renal plasma flow, solute clearance (Cosm), solute-free water reabsorption (TC, H2O) and plasma renin activity (P.R.A.). None of these effects was observed when captopril was similarly administered to sheep pretreated with angiotensin II (AII) receptor blocker, 1-sarcosine-8-isoleucine-AII (sarileucin). It is concluded that the effects of captopril were probably not due to bradykinin potentiation but rather to decreased levels of circulating AII. The effect of sarileucin itself was complex. It effectively blocked the pressor response to administered AII, but it also had an AII-like effect indicated by a rise in R.V.R., and decreases in V, G.F.R., Cosm and TC, H2O. This apparent mixture of AII agonist and antagonist properties probably accounts for the absence of any change in M.A.B.P. or P.R.A. during sarileucin administration.

1-Sarcosine-8-Isoleucine Angiotensin II↗

Dimensions of assertiveness: factor analysis of five assertion inventories.

Five self report assertiveness inventories were factor analyzed. In each case two major factors emerged, accounting for approximately one-quarter to a third of the variance. The findings emphasize the multidimensional nature of current measures of assertiveness, and suggest the construction of a more systematic and psychometrically evaluated scale that would yield subscale scores assessing the separate dimensions of assertiveness.

Adolescent↗

Results of clean intermittent catheterization for children with neurogenic bladders.

Forty-nine patients were placed on a regimen of clean intermittent catheterization one to four years prior to this review. The children were intermittently catheterized, and a silver nitrate solution 1:1000 was instilled after each catheterization. Nurse practitioners, and community and school personnel contributed to the management. Twenty-one patients were continent with anticholinergics, and 18 also required alpha-adrenergic agents. Eighty-eight per cent were essentially bacteriuria-free, 65 per cent were essentially infection-free, and forty-nine per cent were totally continent. The remaining 25 had mild incontinence. Eleven had clearances below 85 mm/min with 8 reverting to normal on therapy. Nine had reflux prior to the study and one improved. In 8 patients reflux developed during therapy; 4 had severe reflux which required ureteral reimplantation. The results demonstrated that a clean intermittent catheterization program is feasible in a rural setting and that a genitourinary irrigant does decrease bacteriuria.

Bacteriuria↗

Do organophosphate insecticides inhibit the conversion of tryptophan to NAD+ in ovo?

The hypothesis that organophosphate (OP) insecticides reduce the NAD+ levels of chick embryos by inhibiting kynurenine formamidase was tested. Fertile chicken eggs at 3 days of incubation were treated with a teratogenic dose of the organophosphate insecticide diazinon (DZN) in the presence or absence of exogenous L-tryptophan or nicotinamide, or one of the metabolic intermediates (L-kynurenine, 3-hydroxyanthranilic acid, quinolinic acid) between tryptophan and NAD+. By day 10 of development, DZN reduced the NAD+ content of the hind limbs of the embryos to less than 20% of normal and by day 15 it caused severe type I and type II teratogenic responses. The co-presence of tryptophan or one of its metabolites served to maintain the NAD+ levels of DZN-treated embryos close to or above normal and significantly alleviated the symptoms of type I teratisms. Tryptophan is virtually as effective as most of its metabolites in suppressing the effects of DZN on the NAD+ content and physical development of the embryos. This equivalence does not support the proposition that the inhibition of kynurenine formamidase causes the lowered NAD+ levels involved in OP-induced type I teratogenesis. It is consistent with the concept that the insecticide acts to decrease the availability of tryptophan to the embryo.

Abnormalities, Drug-Induced↗

The effects of an angiotensin blocker (saralasin) on kidney function in dehydrated sheep.

Saralasin, an angiotensin II analogue and receptor blocker, was infused at 7 and 15 micrograms . min-1 into dehydrated conscious Merino ewes. This caused mean arterial blood pressure, cardiac output, heart rate and renal vascular resistance to fall, and central venous pressure to rise. Renal plasma flow was unaffected but there were significant reductions in glomerular filtration rate, filtration fraction, urine flow, sodium and potassium excretion, solute clearance and solute-free water reabsorption. It is suggested that saralasin produced these effects by inhibiting endogenous angiotensin II activity, and in particular by causing a reduction in renal post-glomerular resistance. This in turn caused a fall in glomerular filtration rate and filtration fraction. While saralasin might have had effects on renal tubular function and perhaps on vasopressin secretion, the observed effects on renal function can be explained by the decrease in glomerular filtration rate and filtration fraction.

Angiotensin II↗

Dental study in patients with rheumatoid arthritis.

Twenty-one patients with rheumatoid arthritis took part in a comparison of three toothbrushes, each used for one month in a randomized trial. The three toothbrushes were a conventional toothbrush with modified handle to allow ease of gripping, an electric toothbrush, and thirdly a finger-stall attached to a normal toothbrush. There was no change in the patients' rheumatoid status during the trial. The patients were scored for plaque and gingival changes but no difference was found between the three toothbrushes. We recommend a standard toothbrush with a modified grip for the rheumatoid hand; the extra expense of an electric toothbrush cannot be justified.

Arthritis, Rheumatoid↗

Hypertension after coronary operation. Can it be prevented by pulsatile perfusion?

Nonpulsatile perfusion during cardiopulmonary bypass (CPB) has been implicated as a causative factor of postoperative hypertension. In a consecutive series, patients undergoing coronary bypass were selected for perfusion with either nonpulsatile flow (American Optical roller pump) or pulsatile flow (Desjardin's modification of the roller pump). The incidence of postoperative hypertension and the levels of peripheral renin were noted. No differences could be observed in renin activity, with either modality of perfusion, before CPB, after 30 minutes of stable CPB, or 2 hours postoperatively. Hypertension, necessitating treatment, occurred in 60% of the patients having pulsatile and 68% of those having nonpulsatile perfusion (p less than 0.05). Although pulsatile CPB would appear to be more physiological than nonpulsatile perfusion, this method of creating pulsatile flow does not appear to eliminate postoperative hypertension.

Cardiopulmonary Bypass↗

Metronidazole for vaginal trichomoniasis. Seven-day vs single-dose regimens.

This randomized, double-blind evaluation of metronidazole therapy for trichomonal vaginitis compared the efficacy and side effects of a single 2-g dose and the standard seven-day regimen (250 mg three thimes daily). Eighty (86%) of the 93 women examined seven to 21 days after therapy with the 2-g regimen, and 76 (91.6%) of 83 examined after the seven-day regimen, were cured. These cure rates were not significantly different. In addition, symptom duration and the occurrence of side effects and yeast infection were not significantly different for the two treatment groups. Because the efficacy and side effects of the two regimens are comparable and the 2-g dose is easier to administer and less expensive, we recommend the 2-g dose as standard treatment for trichomoniasis.

Clinical Trials as Topic↗