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Biomedical subjects

B W Morris

Publications and source records attributed to B W Morris.

15 recordsLinked to original sources
PubMed1992

The trace element chromium--a role in glucose homeostasis.

To better define the normal metabolism of the trace element chromium, we studied its diurnal variation and its response to an oral glucose challenge in nine healthy volunteers. Plasma and urine chromium concentrations were measured by electrothermal atomic-absorption spectroscopy and plasma insulin by radioimmunoassay. A significant inverse relationship was found between plasma chromium and plasma insulin concentrations both over a 24-h period (P less than 0.001) and after a 75-g glucose load (P less than 0.01). This interesting observation, suggesting the removal of chromium from the plasma compartment after meals (confirmed by glucose tolerance test), is not explained simply by increased urinary loss but might be explained by transient changes in uptake or binding of chromium by insulin-sensitive tissues.

Adult↗
PubMed1992

Circadian changes in plasma phosphate concentration, urinary phosphate excretion, and cellular phosphate shifts.

The concentration of phosphate (Pi) in plasma, Pi excretion, and the tubular threshold of Pi resorption (TmP/GFR) all increase throughout the day from about 1100 to 0300 h. For plasma [Pi], cosinor analysis yielded the following estimates of the parameters of this pattern (with 95% confidence limits): amplitude = 0.17 (0.07-0.26) mmol/L, phase = peak at 0201 (1127-0342) h, and MESOR = 1.14 (1.11-1.18) mmol/L. The increase in TmP/GFR reflects an underlying change in renal Pi handling, which is not attributable to changes in parathyrin concentrations. The changes in Pi excretion work both for and against the changes in plasma [Pi], at different times. The calculated net nonrenal flux of Pi into the extracellular fluid increases in the morning and remains high until 0300 h, and neither it nor Pi excretion nor plasma [Pi] shows any relation to meals. This illustrates the importance of transient net fluxes of Pi between intracellular and extracellular spaces in the control of hour-to-hour changes of plasma [Pi].

Adult↗
PubMed1989

A longitudinal study of thyroid function in pregnancy.

We undertook a prospective longitudinal study of thyroid function in 36 pregnant women. There were significant increases in thyroxin-binding globulin, thyrotropin, and triiodothyronine. Albumin, free thyroxin (measured by an analog and a nonanalog method), and the free thyroxin index were significantly decreased. Results for the free thyroxin methods were correlated with each other in each trimester. We could find no evidence for artifacts related to albumin or thyroxin-binding globulin with either method for free thyroxin.

Female↗
PubMed1988

Effect of glucose loading on concentrations of chromium in plasma and urine of healthy adults.

We report here a small study designed to identify the effect of a 75-g oral glucose load on concentrations of chromium in plasma and urine of apparently healthy volunteers. We detected a consistent and significant (P less than 0.01) decline in plasma chromium after glucose administration, the nadir of the chromium response coinciding with the zenith of the glucose concentration.

Adult↗
PubMed1984

Retinal damage from the illumination of the operating microscope. An experimental study in pseudophakic monkeys.

An experimental study of retinal damage from the coaxial illumination of the operating microscope was performed in pseudophakic rhesus monkeys. The threshold exposure time for production of an ophthalmoscopically visible lesion was determined, and the lesions were studied with light and electron microscopy. At the "high" illumination setting, the threshold exposure was less than 7 1/2 minutes and consecutive exposures of lesser duration had an additive effect. Histologically, the lesions were identical to those which other authors have described as primarily due to the shorter wavelengths or "blue light mechanism" of damage.

Animals↗
PubMedDate not supplied

Optociliary veins.

Optociliary veins occur in three clinical settings: in chronic central retinal vein obstruction, with retro-orbital tumors, and as congenital anomalies. In the last setting, associated anomalies of the disc and retinal vessels may be present, which makes differentiation from the first two difficult. Fluorescein angiography may be of value in making this differentiation for, in some if not all congenital OC veins, the direction of flow is from the choroid into the central retinal vein. Two cases are presented in which a congenital optociliary vein was present in association with a fundus picture mimicking a central retinal vein obstruction or papilledema. In both cases, fluorescein angiography demonstrated that the vessel was a congenital anomaly, draining from the choroid into the retina.

Child↗