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Biomedical subjects

M L Levin

Publications and source records attributed to M L Levin.

At least 73 records · Page 4Linked to original sources

Lung cancer mortality in males screened by chest X-ray and cytologic sputum examination: a preliminary report.

Observations from the continuing JHLP lung cancer screening study provide no clear evidence that mass screening by chest X-ray and sputum cytology, plus prompt appropriate treatment, reduces mortality du to lung cancer. No reduction in lung cancer deaths is observed in the JHLP when compared with the number of lung cancer deaths expected from the experience of two unscreened male populations of the same age and smoking status serving as population studies. Possible reasons for the lack of demonstrable decrease in mortality, even though "early" cases have been detected, include: (1) an insufficient passage of time for slowly growing cancers to become apparent in the control group, (2) ineffective therapy, and (3) the multifocal nature of pulmonary neoplasms. Additional study will be required to provide a definitive answer regarding the benefit, if any, of lung cancer screening.

Aged↗

Tuberculosis risk for hospital employees: analysis of a five-year tuberculin skin testing program.

This study of hospital employee tuberculin conversion rates was undertaken in a 516-bed urban general hospital to determine if employment in such a hospital placed employees at risk of infection with tuberculosis. Data collected on the tuberculin status of employees from 1971 through 1976 indicated that the five-year conversion rate for all employees in a hospital-wide testing program was 7.1 per cent. Employees at greatest risk for conversion were non-White, age 46 through 64, in the lowest socioeconomic quintile, and employed in the Laundry, Housekeeping, and Engineering and Maintenance Departments. It was concluded that the higher than expected employee conversion rate was not attributable to exposure to infectious patients, but to a combination of the booster effect in serial tuberculin testing, use of a multiple puncture device for skin tests, and exposure to tuberculosis in the community.

Female↗

Tissue and glomerular deposition of globulin aggregates.

We studied the behavior of AgGG, a model of iCs, in the rat. The clearance of radiolabeled AgGG from the circulation was found to follow first-order kinetics. The t1/2 of the AgGG increased markedly with increases in dose administered, whereas the absolute rate of removal appeared to approach a maximum. The bulk of the AgGG cleared was found in the liver, and less than 1% was found in spleen, lung, or kidney. All these features are typical of the behavior of macromolecules removed from the circulation by the RES. Specific glomerular deposition was studied at various dosages by isolating glomeruli and measuring the fraction of injected aggregate that was trapped. This fraction represented less than 10% of total renal deposits. Moreover, when animals were sacrificed at an interval of 1 t1/2 after the injection of the corresponding dose, the fraction deposited in glomeruli remained constant. The significance of this finding is discussed in relation to the pathogenesis of glomerulonephritis.

Animals↗

Hyponatremia.

Our approach to the hyponatremic patient is based on thorough history and a well-performed physical examination. Bedside evaluation will help the physician to decide whether a patient is dry, wet, or neither. Once the patient has been characterized, an appropriate diagnosis can be established. A few simple laboratory tests will be of assistance: BUN, creatinine, osmolality, uric acid, serum potassium, and spot urinary sodium and osmolality. A logical diagnosis and therapeutic approach can then be achieved.

Ascites↗

Effect of mannitol on acute amphotericin B nephrotoxicity.

This study was undertaken to examine the value of mannitol as protection against the acute nephrotoxicity of amphotericin B under controlled conditions in a reproducible model of toxicity in the dog. Eleven dogs received amphotericin B, 2.5 mg x kg-1 b. wt. by i.v. infusion over a 4-h period. Six dogs were treated with mannitol, 6.25 g, i.v. every hour and five served as controls. Urinary volume (V), inulin clearance (CIn), p-aminohippurate clearance (CPAH), and Na excretion (UNaV) were measured every hour throughout the experiment. Although a higher urinary output was maintained in mannitol-treated dogs, a progressive decline in renal function was observed in treated and in control dogs. During the 4th h, mannitol-treated dogs showed higher CIn (37.4 vs. 19.7 ml x min-1 and CPAH (95 vs. 54 ml x min-1 than controls. However, statistically the differences were barely significant. The results fail to show that mannitol offers a definite protection against amphotericin B nephrotoxicity.

Amphotericin B↗

Bat-associated histoplasmosis in Maryland bridge workers.

An epidemic of acute prolonged febrile respiratory disease affecting nine of 19 workers on a Maryland State bridge maintenance crew was diagnosed as histoplasmosis by serologic testing in all and by isolation of the organism in one. In our investigation, it was revealed that work on a particular bridge was associated with disease. Culture of bat guano from the site two months later revealed H. capsulatum. Four previously uninfected epidemiologic investigators also became ill with histoplasmosis following collection of soil and bat guano. This outbreak reveals that bats and bat guano are a source of histoplasmosis, suggests that only brief exposure is necessary for acute infection and reemphasizes that histoplasmosis is not confined to the midwestern states.

Animals↗

Variations in serum complement following inulin infusion in man.

Complement levels were determined in 12 normal human volunteers while receiving intravenous infusions of inulin for determination of standard inulin clearances. Significant decreases in beta IC globulin and total hemolytic complement activity were observed when inulin was infused, but not following infusion of saline as a control. These effects were noted only when steady-state inulin levels were greater than 26 mg%, suggesting a dose-dependent response. No evidence of increased coagulation was noted as measured by fibrinogen and fibrin degradation products. Since C4 levels remained largely unchanged following inulin infusion, it was concluded that the results most likely occurred through activation of the alternate complement pathway.

Adult↗

Hepatic encephalopathy precipitated by fecal impaction.

Two episodes of hepatic encephalopathy developed in a 64-year-old man with cirrhosis during the course of hospitalization. The first event was precipitated by spontaneous bacterial peritonitis; the second occurred four weeks later and was associated with a massive fecal impaction, an unreported precipitant. No other potential causes were demonstrated. Symptoms promptly resolved following disimpaction.

Fecal Impaction↗

Effect of diuretics on ADP incorporation in kidney mitochondria.

The effect of diuretics on incorporation of ADP in mitochondria isolated from rabbit renal cortex and medulla was examined. Inhibition of incorporation of [14 C]ADP into both types of mitochondria was observed following pretreatment with furosemide, ethacrynic acid and meralluride at high drug concentrations (7.5 x 10-4 M furosemide and ethacrynic acid, 6.4 x 10-3 M meralluride). At lower concentrations (7.5 x 10-5 M furosemide and ethacrynic acid, 6.4 x 10-4 M meralluride), only entry of ADP in medullary mitochondria was inhibited. Chlorothiazide, 1.7 x 10-3 M, did not inhibit incorporation of ADP into either mitochondrial preparation. Atractyloside, a classic inhibitor of ADP-ATP exchange, showed inhibition in both preparations. Furosemide, injected in vivo inhibited incorporation of ADP into medullary but not cortical mitochondria. These results are consistent with the possibility that loop diuretics may reduce tubular sodium reabsorption by inhibiting ADP-ATP exchange across the mitochondrial membrane, thereby depriving active transport processes of ATP. The differential action on cortical and medullary mitochondria by loop diuretics is consistent with their predominant site of action in the tubule and with the different morphologic characteristics of both types of mitochondria.

Adenosine Diphosphate↗