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Biomedical subjects

L Levin

Publications and source records attributed to L Levin.

153 records · Page 9Linked to original sources
PubMedDate not supplied

Reliability and variability in the measurement of interlimbal distance with a semiautomated video replay analysis system (SAVRAS).

This paper reports on the reliability and variability of a semi-automated, video replay and analysis system (SAVRAS) in determining interlimbal distance in patients with strabismus. Factors under investigation were: choice of observer, choice of video frame, patient age and patient state (awake or anesthetized). It was demonstrated that SAVRAS was a highly reliable and reproducible system. This system is currently in use to evaluate the relationship between the succinylcholine induced ocular position, under anesthesia, and the postoperative awake alignment.

Child, Preschool↗
PubMedDate not supplied

Effects of amino acid dialysis compared to dextrose dialysis in children on continuous cycling peritoneal dialysis.

OBJECTIVE: To compare the biochemical and nutritional effects of amino acid dialysis with dextrose dialysis in children receiving continuous cycling peritoneal dialysis (CCPD). DESIGN: A prospective randomized cross-over study. SETTING: Nonhospitalized patients. PATIENTS: Seven children aged 1.8 to 16.0 years (mean 8.1 years) with end-stage renal disease who were receiving CCPD. INTERVENTIONS: Each patient received nighttime automated CCPD of dextrose, plus a single daytime dwell of either amino acid dialysate or dextrose dialysate. After 3 months, subjects crossed over to the alternative regimen for a subsequent 3 months. MAIN OUTCOME MEASURES: Creatinine clearance, ultrafiltration, urea, creatinine, electrolytes, total protein, albumin, fasting plasma amino acids, anthropometrics, total body nitrogen. RESULTS: Amino acid dialysis was comparable to dextrose dialysis for creatinine clearance and ultrafiltration. Plasma urea concentrations were higher during amino acid dialysis. No clinical side effects or worsening of metabolic acidosis was observed. Caloric intake increased and protein intake improved. Appetite and total body nitrogen increased in at least half the children during amino acid dialysis. Total plasma protein and albumin concentrations did not change significantly. Fasting plasma concentrations of amino acids after 3 months of amino acid dialysis were comparable to baseline values. For several amino acids, the dose-response curve was blunted after a single amino acid exchange following 3 months of amino acid dialysis, which may, in part, be due to the induction of hepatic enzyme synthesis. CONCLUSIONS: Amino acid dialysis is an efficient form of peritoneal dialysis that should be considered for children with poor nutritional status for whom enteral nutrition supplementation has been unsuccessful. Further study is needed to determine the optimal amount of amino acids to deliver, the best time to administer the amino acid dialysis fluid, and the benefits of adding dextrose to the amino acid solution.

Adolescent↗
PubMedDate not supplied

[Degradation of anthraquinone blue by Trametes trogii].

The ability of the white rot fungus Trametes trogii BAFC 463 (high producer of ligninolytic enzymes, especially laccase and manganese peroxidase) to degrade the dye anthraquinone blue, refractory to bacterial attack, was evaluated. Both tropho- and idiophasic T. trogii cultures in synthetic medium (glucose/asparagine) and complex medium (malt extract/glucose) were able to transform up to 88% dye in 4 hours. The activity of laccase, an oxygen-dependent phenoloxidase which was present at high levels in all the conditions assayed, might be related to the ability of the fungus to degrade the colorant. This is supported by the fact that in bioreactor experiences carried out at pH 4.5 the addition of anthraquinone blue caused a decrease in the levels of soluble oxygen. However, although high levels of laccase were produced at pH 7.5, the enzyme was not active, and neither dye transformation nor loss in the levels of soluble oxygen were quantified.

Anthraquinones↗
PubMedDate not supplied

[Effect of carbon and nitrogen sources on the cellulolytic activity of Trametes trogii].

Trametes trogii was grown in a liquid synthetic medium containing different carbon and nitrogen sources. Enzymatic activities of cellulases (endoglucanase, exoglucanase and beta-glucosidase) were measured in culture supernatants. Organic nitrogen sources were the most favourable for growth and cellulase production. Increasing nitrogen concentrations also increased cellulase production. Among carbon sources, crystalline cellulose, cellobiose and a mixture of carboxymethylcellulose and cellobiose induced maximal endoglucanase production. The optimal concentration of the carbon source was 10 g/l.

Carbon↗
PubMedDate not supplied

[Effect of culture conditions on the production of cellulases by Trametes trogii].

Production of the components of the cellulase complex by Trametes trogii was investigated under different culture conditions. Endoglucanase, exoglucanase and beta-glucosidase were produced by Trametes trogii under shaken and stationary conditions using crystalline cellulose as the only carbon source. No marked differences were found for endo- and exoglucanase production between both culture conditions. In shaken cultures beta-glucosidase values doubled those obtained in stationary conditions. All maxima were reached approximately 10 days earlier in static cultures than in shaken ones. The addition of glucose to the culture medium improved growth but decreased abruptly the enzyme production. The optimal pH of the medium for the synthesis of the enzymes was 5.6, and the best incubation temperature was 25-28 degrees C. Enzyme activities were maximal at pH 3.1 and 45 degrees C (endoglucanase), pH 4.1 and 50 degrees C (exoglucanase) and pH 5.3 and 60 degrees C (beta-glucosidase).

Basidiomycota↗
PubMedDate not supplied

Nutritional requirements for growth of an endophyte: Ceratopycnidium baccharidicola.

The carbon sources, nitrogen sources and vitamin requirements for the growth of Ceratopycnidium baccharidicola (an endophyte of Baccharis coridifolia) were studied. The fungus utilized several carbon sources: pectin, sucrose, fructose, glucose, maltose, cellobiose, xylose, arabinose, mannitol, mannose and sorbitol. Sucrose and fructose were found to be the best carbon sources. Nitrogen sources utilized by the endophyte included: nitrates, ammonium and amino acids such as proline, asparagine and glycine. Undefined complex nitrogen sources such as soytone, tryptone, yeast extract and casamino acids supported excellent growth. In a defined medium, thiamine was the only vitamin required for growth. Under optimum conditions the vegetative growth of C. baccharidicola was enhanced six fold over its growth in glucose-asparagine medium.

Carbohydrate Metabolism↗