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Biomedical subjects

M McVicar

Publications and source records attributed to M McVicar.

31 records · Page 2Linked to original sources
PubMed1977

Experimental lead poisoning and intestinal transport of glucose, amino acids, and sodium.

Juvenile rats fed a diet containing 1% lead acetate for 7 weeks, in addition to an impaired growth rate and renal function derangements, suffered malabsorption of glucose and certain amino acids, as assessed by an in vivo perfusion technique. The reduction in glucose absorption ranged between 10% and 31% when the carbohydrate was pumped in concentrations of 2-80 mM. This alteration was compatible with a noncompetitive type of transport inhibition. The intestinal absorption of glycine, lysine, and phenylalanine were, respectively, decreased 22, 18, and 15% when these amino acids were present at 1 mM levels. Sodium transport was severely reduced (57.6 +/- 17.9 (SEM) vs. 124.2 +/- 17.4 muEq/min-cm) and intestinal mucosa (Na+-K+)-ATPase was concomitantly lower in the lead-intoxicated rats (186.4 +/- 19.0 vs 268.4 +/- 29.8 nmol P/min-mg protein). However, this enzyme was not altered in liver and kidney. Furthermore, intestinal mucosa fructose-1,6-diphosphatase, succinic dehydrogenase, pyruvate kinase, and tryptophan hydroxylase were not different in experimental and control animals. These studies substantiate the presence of functional and biochemical abnormalities in the intestinal mucosa of young rats when fed substantial amounts of a soluble lead salt. It is, therefore, reasonable to accept the possibility that physiologic damage occurs in tissues directly subjected to high and persistent levels of a toxic agents, as it occurs in other organs, underscoring the parallelism between transport mechanisms at the renal and intestinal levels.

Adenosine Triphosphatases↗
PubMed1975

Inhibition of sodium intestinal transport and mucosal (Na+-K+)-ATPase in experimental Fanconi syndrome.

The administration of 1.5 or 9.0 mmoles/kg ip of maleate to rats induced, in addition to renal alterations similar to those occurring in the Fanconi syndrome, a decline in the intestinal mucosa (Na+-K+)-ATPase with a simultaneous decrease in sodium intestinal transport and an increase in potassium absorption. Further differences in the behavior of the two electrolytes were observed when the concentration of sodium in the perfusates was altered. No changes occurred in amino acid or glucose transport in experimental animals.

Adenosine Triphosphatases↗
PubMed1969

Antigenic streptococcal components in acute glomerulonephritis.

Fluorescein-labeled immunoglobulin G fractions from serums of patients with acute glomerulonephritis and from many normal serums stained the glomerular basement membrane and mesangium of renal tissue from patients with early acute glomerulonephritis; these serums did not stain the corresponding tissues from patients with any other kidney disease. Previous absorption of the serum fraction with frozen and thawed nephritogenic beta hemolytic streptococci abolished all staining. Other bacteria studied did not abolish the staining. Only the plasma membrane of the streptococcus absorbed the immunoglobulin G fraction; such absorption eliminated staining. Fluorescein-labeled antiserums against streptococcal plasma membrane had staining properties similar to patients' serums.

Absorption↗
PubMedDate not supplied

Effects of amino acid additives during hemodialysis of children.

The intradialytic losses into the dialysate of free amino acids (AA) and alpha-amino nitrogen were determined during the dialysis of three children. Variations in plasma AA were determined pre- and postdialysis. The effect of these losses with the addition of an Abbott General Amino Acid Mixture to the dialysate in concentrations of 8.5, 17, and 34 mg/100 ml was studied. The major determinant of AA losses was the plasma concentration of the AA before beginning the dialysis treatment. Dialysance of individual AA varied inversely with their molecular weights. A zero flux of alpha-amino nitrogen occurred at a derived concentration of 22 mg/100 ml of the AA additive in the dialysate. Plasma concentrations of nonessential amino acids were little affected by the dialysate additive. In contrast, total essential amino acid nitrogen which fell during baseline dialyses showed significant improvement when the AA solution was added to the dialysate. This study suggests that the addition of AA to the dialysate bath may be effective in decreasing AA nitrogen losses during dialysis.

Adolescent↗
PubMedDate not supplied

Pathologic characterization of a renin-secreting juxtaglomerular cell tumor in a child and review of the pediatric literature.

We describe a rare case of renal hypertension in a 15-year-old caused by juxtaglomerular cell tumor and compare our findings with those of 20 children reported in the literature. These tumors are usually encapsulated and composed microscopically of polyhedral cells with bland nuclei separated by fibrovascular septa. Characteristic renin granules can be demonstrated by Bowie's stain or electron microscopy. These tumors are benign. Pathologists should recognize the morphologic characteristics of these tumors when dealing with renin-producing neoplasia.

Adolescent↗
PubMedDate not supplied

Rapid onset of co-trimoxazole induced interstitial nephritis.

An infant developed anuric renal failure within 18 hours of starting therapy with Co-trimoxazole for otitis media. There was no prior exposure to Co-trimoxazole, sulfonamides or trimethoprim. A renal biopsy revealed acute interstitial nephritis with eosinophilic infiltration (AIN). The lymphocyte blast transformation test revealed increased proliferation of the patient's lymphocytes on exposure to Co-trimoxazole (Bactrim). Both parents have clinically demonstrated hypersensitivity to sulfonamides. The extremely short latent period between ingestion of the offending drug and the onset of AIN in the absence of prior exposure to the drug has been reported previously. It suggests that drug induced AIN may develop more rapidly in patients with a strong genetic hypersensitivity to the drug.

Anti-Infective Agents↗
PubMedDate not supplied

Urinary lactate dehydrogenase isoenzyme analysis in adult population.

This investigation was a systemic study on an adult population of urinary lactate dehydrogenase (LDH) isoenzyme analysis for the distinction between upper and lower urinary tract infections. The study included 160 urine samples from patients and healthy individuals. On the basis of clinical symptoms, urinary bacterial colony counts, renal function tests and radiologic findings, the adults were divided into pyelonephritis group, cystitis group, pelvic lesion group, and control group. This technique correctly identified 23 of 26 patients with pyelonephritis by the presence of elevated LDH-V (over 10 percent) and all of 12 patients with cystitis by the presence of elevated LDH-I (over 60 relative units) but low LDH-V (below 10 percent or lower than LDH-I). In the pelvic group, the results of eight patients were consistent with cystitis and four with pyelonephritis. Our study confirms the sensitivity and specificity of the LDH isoenzyme technique for the differential diagnosis of urinary tract infection on adult patients and is consistent with previous studies on pediatric patients. However, one should be cautious to interpret the results of LDH isoenzymogram before extra-urinary tract lesions are excluded.

Adolescent↗