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Biomedical subjects

A L Zimmerman

Publications and source records attributed to A L Zimmerman.

25 records · Page 2Linked to original sources
PubMed1978

Changes in serum electrolyte levels during marathon running.

Serum electrolytes were measured in 18 well-trained, experienced long-distance runners before and after a standard marathon run (42 km), during which they ingested no electrolytes. Their sweat losses and water deficits after completion of the marathon were also measured. In 12 of the subjects, the percentage change in plasma volume and in total circulating plasma electrolytes was determined. There was a highly significant fall in serum magnesium concentration, with an increase in both potassium and sodium levels. Changes in total circulating plasma sodium and chloride were closely correlated with alterations in plasma volume. On the basis of these observations, it is recommended that athletes drink an augmented volume of fluid during marathon running, irrespective of the prevailing weather conditions. Supplementation of potassium and magnesium is contraindicated during long-distance running. Salt intake is unnecessary during races over the standard marathon distance. Subjective evidence for glucose supplementation is presented.

Adult↗
PubMed1975

Acute renal failure secondary to ureteral fungus ball obstruction in a patient with reversible deficient cell-mediated immunity.

A patient with a single functioning kidney and anuria due to ureteropelvic obstruction by a Candida fungus ball is described. During treatment with amphotericin B administered via a nephrostomy tube the drug was not detected in the serum, indicating that absorption from urothelium was not significant. Immunological studies demonstrated a lack of cell-mediated immunity which was probably brought about by a long course of prednisone and later restored when this drug was discontinued. This immunosuppression was evident even with a relatively small dosage of prednisone (5 mg daily). The literature concerning renal candidiasis and predisposing factors is reviewed.

Acute Kidney Injury↗
PubMedDate not supplied

Perfusion system components release agents that distort functional properties of rod cyclic nucleotide-gated ion channels.

In switching from studying native cyclic nucleotide-gated (CNG) ion channels in rod cells to studying the corresponding cloned channels expressed in Xenopus oocytes, we changed our perfusion system to a more efficient one. This change involved replacing culture flasks and a small plexiglass/glass chamber with plastic syringes, metal needles, and plastic petri dishes. We now report that these new perfusion system components release agents that distort or obscure measured functional properties of rod CNG channels. The magnitude and time course of appearance of the artifacts vary widely among individual components (e.g. from syringe to syringe). The effects most resemble voltage-dependent block of the channels, giving a decrease in current at positive potentials, and producing distortions of the kinetics and voltage dependence of channel activation.

Animals↗
PubMedDate not supplied

Cyclic GMP-sensitive conductance of retinal rods consists of aqueous pores.

The surface membrane of retinal rod and cone outer segments contains a cation-selective conductance which is activated by 3',5'-cyclic guanosine monophosphate (cGMP). Reduction of this conductance by a light-induced decrease in the cytoplasmic concentration of cGMP appears to generate the electrical response to light, but little is known about the molecular nature of the conductance. The estimated unitary conductance is so small that ion transport might occur via either a carrier or a pore mechanism. Here we report recordings of cGMP-activated single-channel currents from excised rod outer segment patches bathed in solutions low in divalent cations. Two elementary conductances, of approximately 24 and 8 pS, were observed. These conductances are too large to be accounted for by carrier transport, indicating that the cGMP-activated conductance consists of aqueous pores. The dependence of the channel activation on the concentration of cGMP suggests that opening of the pore is triggered by cooperative binding of at least three cGMP molecules.

Animals↗
PubMedDate not supplied

The incidence and significance of intracytoplasmic calcifications in nipple aspirate specimens.

Intracytoplasmic deposits demonstrated to be calcifications have been identified in nipple aspirates from 3.6 per cent of breasts with satisfactory cytology. The deposits occurred almost exclusively in epithelial groups, and their structure ranged from dust-like particles and spiculated forms to psammoma bodies; all exhibited characteristic density, refractility and well-defined, irregular borders. Nipple aspirates containing calcifications were typically characterized by the presence of numerous epithelial groups, frequently of papillary type. This association was supported histologically by the fact that 11 of the 14 available tissue specimens contained papillary lesions in the duct system, including three with papillary carcinoma in situ. Cytologic abnormality was significantly associated with the presence of calcifications, and marked cellular changes were found four times as often in this group as in the total population with satisfactory cytology. Calcific deposits were found in six of the fourteen available tissue specimens, four of which contained breast carcinoma. Calcifications were noted in only 23 per cent of 97 available mammograms, but further investigation has revealed other significant radiologic findings. Cytologic calcifications were found most frequently in aspirates from women between the ages of 41 and 60 and were often associated with clinical findings of breast disease. Preliminary findings indicate an increased prevalence of breast carcinoma in patients with cytologic calcifications and suggest that such patients may require closer than normal follow-up.

Adult↗
PubMedDate not supplied

Plasminogen activator as a diagnostic marker for preneoplastic cells in human gynecologic specimens.

A modified fibrin-agar overlay assay was used to measure the fibrinolytic activity in human cervical epithelial cells. The fibrinolytic activity results from a cell-associated serine protease that acts as a plasminogen activator. An enzymatic and morphologic comparison of individual normal and abnormal cells reveals that about 50% of the dysplastic and carcinoma in situ cells contain high levels of the activator. Forty percent of morphologically normal metaplastic cells also exhibit high activities of plasminogen. Forty percent of morphologically normal metaplastic cells also exhibit high activities of plasminogen activator. Most normal intermediate and superficial epithelial cells and all erythrocytes and leukocytes are inactive. The frequency of plasminogen activator-containing cells was somewhat higher in cytomorphologically abnormal samples than in normal samples.

Carcinoma in Situ↗