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Biomedical subjects

D L Olson

Publications and source records attributed to D L Olson.

51 records · Page 3Linked to original sources

Renovascular hypertension in children and adolescents.

Renovascular disease often leads to hypertension in children. The most frequent cause is fibromuscular dysplasia of focal type affecting main and peripheral arteries. Diastolic readings in excess of 110 mm Hg with normal serum creatinine and urinalysis are suggestive of renovascular disease. Excretory urography was positive in 65% of patients with unilateral disease. Radionuclide scans complement a positive excretory urogram but may be positive when the urogram is negative. Plasma renin activity was raised in the majority of patients; if the patient does not have peripheral branch stenosis, the renal vein renin ratio will lateralize in unilateral renal disease. The overall results of surgery are encouraging: 86% of surgical procedures alleviated hypertension in unilateral disease.

Adolescent↗

The occurrence and distribution of furan fatty acids in spawning male freshwater fish.

Furan fatty acids (F acids) have been found in the livers and/or testes of 20 species, representing 9 families, of male freshwater fish. In 9 species they are major components of the lipids while in the remaining 11 species they occur to a much lesser extent. The F acids in some species reach a maximum concentation in the testes lipids, and minimum liver lipid concentration, at spawning. In all species in the testes, the F acids are confined almost exclusively to the triglyceride fraction while, in the liver lipids, they are found, in order of decreasing concentration, in the cholesteryl esters, the triglycerides, and the phospholipids. In the lipids of many individuals F6, 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid, is the major fatty acid present. It is presumed that these acids perform some as yet unidentified metabolic function. Isolation technology and identification of F acids by a specific thin layer chromatographic spray reagent are discussed.

Animals↗

Renal hypertension in children.

Preliminary results of this retrospective-prospective analysis of renal hypertension in 110 children indicate that hypertension may be secondary to a wide variety of acute progresive, and chronic renal diseases which may be either congenital or acquired. Affected children may be detected at any time from infancy through adolescence. Symptoms usually associated with acute glomerulonephritis (i.e., headache, swelling, nausea, vomiting, anorexia, fatigue, dizziness, and fever) occur in both acute and chronic renal diseases associated with hypertension. Headache and swelling are the most common symptoms in this series. Peripheral edema, rales, and increased heart size were found in between 10 and 25% of these children. Differential diagnosis may be approached by a consideration of causes of acute and chronic hypertension. The child with chronic renal disease usually presents with a long history of fatigability, poor growth, and pallor, and laboratory tests reveal elevation of the creatinine and BUN along with anemia, hypocalcemia, and hyperphosphatemia. In contrast, the child with acute renal disease and hypertension presents with a history of prior good health followed by the abrupt onset of signs and symptoms of renal disease; laboratory tests usually reveal modest elevations of creatinine and BUN, anemia is unusual, an abnormal urinalysis is common, and serum calcium and phosphorous levels are usually normal. Renovascular and asymmetric renal parenchymal disease represent uncommon but important conditions because surgery may be curative. Treatment may be surgical, medical, or combined. Surgical conditions include renal trauma, hydronephrosis, asymmetric renal disease, and renal arterial disease. Adequate blood pressure control without medication can be expected following surgery in instances of unilateral involvement with a normal contralateral kidney. Meticulous assessment of the contralateral kidney is needed to determine that it is normal. If surgery is unsuccessful or is not indicated, pharmacologic therapy is initiated with a stepwise regimen starting with the mildest agent (e.g., thiazides) and then adding additional antihypertensive drugs when adequate blood pressure control has not yet been achieved. The goal of therapy is the lowest, safest, tolerated blood pressure levels. Long-term, carefully designed studies of antihypertensive agents for children with renal hypertension are not available. The need for collection and critical analysis of data concerning the clinical course of children with renal hypertension is evident from a review of the literature and from the preliminary data presented in this series. The presentation of such information and a critique of outcome variables will provide a basis for program planning for affected children and improvement in patient care where indicated.

Adolescent↗

Cystinosis. Intracellular cystine depletion by aminothiols in vitro and in vivo.

Certain aminothiols rapidly deplete cultured cystinotic skin fibroblasts of their abnormally high free (nonprotein) cystine pool. The free cystine content of these cells if reduced by over 90% in 1 h with 0.1 mM cysteamine. This is more rapid than previously known methods of removing free cystine from cystinotic fibroblasts. The disulfide, cystamine, is also able to deplete cystinotic cells of free cystine. A patient with nephropathic cystinosis and end-stage renal disease was treated with cysteamine, both intravenously and orally. Both methods of administration rapidly lowered the free cystine content of the patient's peripheral leukocytes. Study of the patient's urinary sulfur excretion did not conclusively determine the effect of this therapy on the total body cystine pool. Her renal status remained at end stage after 1 mo of oral cysteamine, when an episode of grand mal seizures prompted cessation of the study. Determination of the proper place of aminothiol therapy in this disease will depend upon further clinical trial with patients whose kidney function has not deteriorated to the point of irreversible change, accompanied by careful monitoring of plasma aminothiol levels.

Child↗

Physical therapy and exercise-induced bronchospasm.

Most asthmatic children develop a significant degree of bronchospasm from exercise which restricts their active participation in outdoor play and sports and sometimes leads to many social and psychological problems. No specific physiological or immunological factors have yet been found to explain the basis of this exercise-induced bronchospasm (EIB). It is also unrelated to age, sex, or severity of asthma. Some investigators have hypothesized that EIB may be a conditioned response resulting from the association between the physical exertion and breathing difficulty which is frequently experienced by these children during their asthmatic attacks. Physical activity programs, organized around themes of progressive and interval training periods, may be quite helpful in reducing the intensity of EIB.

Asthma↗

Computed tomography of pulmonary thromboembolism and infarction.

Computed tomographic findings in 18 patients with pulmonary thromboembolism are retrospectively reviewed. In the majority of patients, thromboembolism was not suspected clinically. The CT findings can be divided into two groups: vascular and parenchymal changes. The most frequent vascular findings is an intraluminal filling defect or defects due to thrombus. The most frequent parenchymal finding is a triangular (wedge-shaped) pleural-based soft tissue attenuation lesion. Although CT is not a primary diagnostic tool in the evaluation of pulmonary thromboembolism, CT may be helpful in diagnosis of pulmonary embolism, when evaluating an undiagnosed parenchymal density.

Adult↗