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Biomedical subjects

R S Abernathy

Publications and source records attributed to R S Abernathy.

35 records · Page 2Linked to original sources

Serum angiotensin-converting enzyme activity in normal children and in those with sarcoidosis.

Serum angiotensin-converting enzyme was measured in 185 children of different ages, in 32 normal adults, in 21 children with sarcoidosis, and in 36 children with other diseases. Children had higher serum ACE volumes than did adults; an intermediate level was absorbed in adolescents. Serum ACE values did not vary according to sex. Children with sarcoidosis had significantly elevated serum ACE levels that closely reflected the activity of the disease. Our results indicate that serum ACE is useful in confirming the diagnosis of sarcoidosis in childhood, and is of greater value as a sensitive indicator for following the course of the disease and the effectiveness of steroid therapy.

Adolescent↗

Nephropathy associated with methicillin therapy. Prevalence and determinants in patients with staphylococcal bacteremia.

The nephropathy associated with methicillin sodium therapy is considered to be rare, but its prevalence is unknown. We reviewed the antibiotic therapy of 81 cases of Staphylococcus aureus bacteremia to establish the frequency and determinants of methicillin nephropathy in that disease. Fifty-two patients received methicillin; nine (17%) experienced the characteristic clinical signs previously associated with drug-induced acute interstitial nephritis. This nephropathy uniformly subsided after methicillin was withdrawn, and did not always include deterioration of renal function. Factors that correlated with methicillin nephropathy were endocarditis and prolonged treatment, but not intravenous drug abuse. There was only one adverse reaction among 29 patients treated with a cephalosporin. It was similar to the nephropathic reactions to methicillin. Thus, reversible renal abnormalities are prevalent during methicillin therapy, particularly among patients with staphylococcal infections such as endocarditis. When prolonged therapy with methicillin is required, the urinary sediment and renal excretory function should be monitored.

Adult↗

Bulging fontanelle as presenting sign in cystic fibrosis. Vitamin A metabolism and effect on cerebrospinal fluid pressure.

A 51/2-month-old infant had the single problem of a bulging fontanelle. A diagnosis of cystic fibrosis with secondary hypovitaminosis A was made by the findings of high sweat chloride values and a low serum carotene level. A greatly accelerated rate of weight gain following the addition of pancreatic enzyme supplements confirmed the presence of malabsorption. The infant developed characteristic fibrosis pulmonary disease at 20 months of age. Animal studies have shown vitamin A deficiency to be associated with increased cerebrospinal fluid (CSF) pressure, diminished absorption of CSF, and pathological findings of thickening and infiltration with mucopolysaccharides of the dura mater around the arachnoid villi.

Child, Preschool↗

Effect of rapid intravenous infusion on serum concentrations of amphotericin B.

The magnitude of the concentrations of amphotericin B produced in serum of patients with systemic mycoses may significantly influence the outcome of therapy with this drug. Since amphotericin B is conventionally administered in intravenous infusions lasting 4 to 6 hr, we asked whether faster infusions of this drug might yield higher serum concentrations without an increase in dose. This question was studied in three patients who received 16 infusions of this drug: eight infusions administered slowly (5 hr) and eight administered rapidly (45 min). Serum concentrations after each rapid infusion were compared with those after a slow infusion administered to the same patient. The mean serum concentration of amphotericin B 1 hr after the rapid infusions (2.02 mug/ml) was significantly higher (P < 0.001) than the mean serum concentration of amphotericin B 1 hr after the slow infusions of this drug (1.18 mug/ml). Mean serum concentrations 18 and 42 hr after rapid infusion remained slightly but not significantly higher than respective mean concentrations after slow infusions. By yielding higher initial serum concentration, rapid intravenous infusion may be therapeutically more effective than slow infusion of amphotericin B. Although rapid infusions caused no more toxicity than did slow infusions, the lack of greater toxicity with rapid infusion of amphotericin B should be further documented prior to extensive clinical application of this procedure.

Amphotericin B↗

Amphotericin B serum concentrations during therapy.

Therapeutic outcome of patients being treated for systemic mycoses with amphotericin B is possibly related to the serum concentrations of this drug that are produced in these patients. Because current data are conflicting, the magnitude of these concentrations was restudied by using a bioassay which gave precise and accurate results. The highest of 155 serum concentrations was 2.01 mug/ml. Mean concentrations were 1.21, 0.62, and 0.32 mug/ml, at 1, 18, and 42 hr, respectively, after intravenous infusion of amphotericin B. This drug was detected in serum 7 weeks after completion of treatment, but it could not be detected 13 weeks after treatment. Drug levels did not appreciably decrease in serum stored for 8 to 9 months at - 10 C. Unequal serum content in assay tubes and measurement of assay turbidity by visual inspection may explain previously reported amphotericin B levels of 3.0 to 12.5 mug/ml.

Amphotericin B↗

Systemic blastomycosis in children.

Ten pediatric patients with systemic blastomycosis in Arkansas are reviewed. No particular age predisposition in childhood is apparent and there has been no change in incidence over the previous 40 years. Six of the 10 cases were male and 8 were black. Organ systems most commonly involved were pulmonary, skeletal and skin. With current therapy, usually amphotericin B as a single agent, the case fatality rate is less than 10%. Early recognition and institution of appropriate antifungal treatment remain the most important factors for survival and prevention of chronic pulmonary disease.

Adolescent↗

Antioxidant enzyme activity in murine hematopoietic bone marrow following treatment with interleukin 1 alpha: influence of tumor.

To determine whether non-hematologic tumors influence the bone marrow's antioxidant enzyme response to the radioprotective cytokine interleukin 1 alpha (IL-1), studies were undertaken using BDF1 and Balb/c mice bearing small, medium or large Lewis lung carcinoma (LLCa) or EMT6 mammary carcinoma tumors, respectively. Results demonstrated that, similar to nontumor-bearing mice, treatment of tumor-bearing animals with IL-1 was associated with a significant increase in marrow MnSOD activity. However, the duration of this elevated activity was reduced as tumor burden increased, and this reduction may have an impact on IL-1's ability to radioprotect tumor bearing animals, especially when tumor burden is large. In addition to cytokine-mediated responses, significant tumor-related influences on the marrow's antioxidant enzyme status were seen. Notably, it was observed that the presence of tumor was correlated with a marked suppression of antioxidant enzyme activity. Surprisingly, however, the pattern of enzyme suppression was found to differ between the two tumor models studied both in temporal onset and in the number of enzymes involved. In conclusion, the data obtained from these studies on tumor-bearing animals demonstrate that there are both cytokine-related and tumor-related influences which can effect the antioxidant enzyme status of the hematopoietic marrow-influences which may have the potential to alter the marrow's ability to tolerate free radical-generating events, both endogenous (i.e inflammation, infection) and exogenous (i.e. radiation, certain chemotherapeutic drugs) in origin.

Animals↗