Search PubMed⌕ Search

Biomedical subjects

M Henderson

Publications and source records attributed to M Henderson.

At least 145 records · Page 8Linked to original sources
PubMed1979

Drosophila alcohol dehydrogenase activity in vitro and in vivo: effects of acetone feeding.

When adult Drosophila are placed on medium containing 0.5% acetone, their level of alcohol dehydrogenase activity drops rapidly. At the same time, the proportion of activity in the various electrophoretic forms of the enzyme shifts; most of the activity becomes localized in what is ordinarily a minor form of the enzyme. Moreover, the loss of enzyme activity occurs in vivo as well, as shown by sensitivity to ethanol poisoning, insensitivity to pentenol treatment, and inability to utilize ethanol as an energy source. These observations are discussed in light of a model advanced for the origin of the multiple forms of alcohol dehydrogenase in Drosophila.

Acetone↗
PubMed1979

Inhibition by angiotensin II of some vasopressin effects on renal function in sheep.

The effects of intravenous infusions of arginine vasopressin (AVP) alone and with angiotensin II (AII) on renal function were studied in conscious Merino ewes. AVP at 11.5 pmol.min-1 caused an increase in water and electrolyte output which was associated with a rise in glomerular filtration rate (GFR), solute clearance, solute-free water reabsorption and tubular sodium reabsorption. Addition of AII of 100 ng.min-1 generally reversed all of these effects. The filtration fraction, which rose during AVP infusion, increased further when AII was added due to a greater fall in renal plasma flow than in GFR. The diuretic and electrolyte-excreting effects of infused AVP appeared to be brought about by an increase in GFR. It is suggested that this inappropriate effect of AVP, which is secreted in response to water deprivation, could be countered by the simultaneous production of AII.

Angiotensin II↗
PubMed1978

The effects of two analogues of arginine-vasopressin (ornithine-vasopressin and desamino-D-arginine-vasopressin) on kidney function in sheep.

The effects of intravenous infusion of ornithine-vasopressin (OVP) and desamino-D-arginine-vasopressin (dDAVP) were studied in normal and hydrated Merino sheep. In normal sheep, OVP resulted in a diuresis, increased urinary sodium and potassium excretion, and a fall in the plasma potassium concentration. Renal plasma flow remained constant but glomerular filtration rate and filtration fraction rose markedly. dDAVP in normal sheep was antidiuretic, but its only significant effect was a small decrease in plasma osmolality. In the hydrated sheep OVP was antidiuretic and resulted in increased urinary excretion of sodium and potassium, and a fall in the plasma potassium level. Renal plasma flow fell, but glomerular filtration and filtration fraction tended to rise. dDAVP in the hydrated sheep was also antidiuretic but urinary sodium and potassium excretion was reduced. Renal plasma flow and glomerular filtration fell, with a small decrease in filtration fraction. These results suggest that the diuretic effect in normal sheep and the electrolyte-excreting effects in both normal and hydrated sheep of OVP are related to the increase in glomerular filtration, which in turn is dependent on the vasopressor activity of the hormone. The increase in glomerular filtration caused by OVP is due to an increase in the filtration fraction of an unchanged renal plasma flow, which could be brought about by an increase in renal efferent arteriolar tone. The effects of hydration of the sheep were the conventional increased urine flow, decreased urine osmolality and decreased solute-free water reabsorption. Sodium and potassium excretion rose slightly and plasma osmolality fell. Renal plasma flow and glomerular filtration both increased with little change in filtration fraction. These effects could be brought about by suppression of endogenous vasopressin and a decrease in both afferent and efferent renal arteriolar tone.

Animals↗
PubMed1978

The effect of intravenous hypertonic saline infusion on renal function and vasopressin excretion in sheep.

Conscious Merino ewes were given an intravenous hypertonic sodium chloride load of 4 mmol.min-1 for 100 min. This resulted in increases in urine flow, sodium and potassium excretion and plasma sodium concentration and osmolality. Urinary vasopressin output and solute-free water reabsorption increased and plasma renin activity declined. Renal plasma flow and glomerular filtration rate (GFR) rose, as did the solute clearance. The change in urinary osmolality was related to the initial urine osmolality such that when the initial urine osmolality was high the urine became more dilute, and vice versa. Tubular sodium reabsorption increased but the fractional reabsorption rate fell. It is suggested that the increase in GFR was at least partly due to the increase in AVP and that the electrolyte loss can be accounted for by the increase in GFR without necessarily involving AVP or other hormonal effects at the tubular level.

Animals↗
PubMed1977

Alterations in plasma sialyltransferase levels in patients with neoplastic disease.

Levels of glycoprotein:sialyltransferase activity (EC 2.4.99.1; CMP-acetyl-neuraminate:D-galactosyl-glycoprotein N-acetylneuraminyl-transferase) were measured in plasma of patients with neoplastic disease, and were found elevated above normal control values in 85% of patients examined. There was a correlation between enzyme levels and course of disea-e in 46 of 57 patients studied serially during therapy. Plasma sialyltransferase may be a useful marker enzyme for monitoring effectiveness of therapeutic programs for disseminated neoplasms.

False Positive Reactions↗
PubMed1977

Evaluation of cancer screening programs: parallels with clinical trials.

The methodologic limitations of available observational evidence for the evaluation of ongoing cancer control programs is reviewed. The specific example of Control Programs for Cervical Cancer is chosen to illustrate these limitations. These limitations pertain to the special features of the natural history of this disease, to the types of data available as well as to problems in the interpretation of these data. Given the unacceptability of conducting a rigorous randomized clinical trial of an ongoing and accepted cancer control procedure, an alternative experimental approach is proposed. This approach consists in the random allocation of census tracts with a high risk population to either of two groups: 1) an experimental group in which active and repeated screening activities will attempt to reach virtually all susceptible women, 2) a comparable control group which will only benefit from regularly available services.

Adult↗
PubMed1977

Glycosyltransferase levels in tumors metastatic to liver and in uninvolved liver tissue.

Elevated levels of three plasma glycosyltransferases were associated with neoplasia in cancer patients, notably those with tumor metastatic to liver. We examined levels of sialyltransferase, galactosyltransferase, and fucosyltransferase in metastatic tumor and apparently uninvolved host liver tissue in attempts to delineate possible sources of elevated plasma enzyme levels. Highest levels of fucosyltransferase activity were found associated with tumor tissue; in contrast, sialyltransferase and galactosyltransferase activity was often highest at the tumor-liver interface.

Female↗
PubMed1977

Effect of cimetidine on the human lower oesophageal sphincter.

Lower oesophageal sphincter pressures in healthy volunteers were measured by a rapid pull-through technique during intravenous infusion of the histamine H2-receptor antagonist, cimetidine. No consistent effects on sphincter pressure were observed which are liable to be of clinical importance. Serum gastrin concentrations during cimetidine infusion were measured by radioimmunoassay and showed no significant variation. In a further series of experiments, the response of the lower oesophageal sphincter to intravenous bolus injection of pentagastrin was measured before and during cimetidine infusion. Cimetidine infusion had no significant effect on the sphincter response to pentagastrin.

Adult↗
PubMed1976

Validity of screening.

The technical aspects of evaluation of screening programs to detect early disease are discussed. Screening is differentiated from diagnosis. The practical importance of specificity and sensitivity of screening tests is illustrated. The concept of evaluation of the total program is introduced. The determinants of successful programs are discussed with illustrations.

Epidemiologic Methods↗
PubMed1976

Concentration and purification of enteroviruses by membrane chromatography.

A simple procedure for the concentration and partial purification of enteroviruses from tissue culture harvests is described. After removal of acid-precipitating components with a cationic detergent, the detergent and most membrane-coating components were removed by treatment with a cationic-exchange resin. The resin effluent was then acidified, and the virus was adsorbed to epoxy-fiberglass membranes. Virus was then eluted with pH 11.5 glycine-NaOH buffer. Since this eluate contains no orgcentrated simply by acidifying the eluate and passing it through a smaller membrane than that used for the first concentration. As high as 500-fold concentrations can be achieved, with a high efficiency of recovery.

Adsorption↗
PubMed1976

Phase I study of oral mitomycin C.

This study demonstrates that the gastrointestinal absorption of oral mitomycin C is variable and that myelosuppression correlates most closely with the peak serum concentration. The probable maximal-tolerated dose of oral mitomycin C is 45-50 mg/m2.

Administration, Oral↗