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Biomedical subjects

C Levin

Publications and source records attributed to C Levin.

17 recordsLinked to original sources
PubMed2005

Cutaneous bioassay of salicylic acid as a keratolytic.

Keratolytic efficacy of topical preparations containing salicylic acid was studied in humans utilizing adhesive tape stripping and quantifying SC removal by protein analysis. In combination with tape stripping, squamometry was used to evaluate the influence of salicylic acid on skin surface scaliness and desquamation. Furthermore, skin barrier perturbation and skin irritancy was recorded and related to the dermatopharmacological effect of the preparations. In contrast to squamometry, tape stripping combined with protein analysis was sensitive in detecting keratolytic effect of salicylic acid within hours of application. Importantly, whereas the pH of the preparations only minimally influenced efficacy, local dermatotoxicity was significantly increased at acidic pH. This indicates that the quest to increase the amount of free, non-dissociated SA is, in fact, counterproductive as the more acidic preparations resulted in skin irritation and barrier disruption.

Administration, Cutaneous↗
PubMed2001

Efficacy of corticosteroids in acute experimental irritant contact dermatitis?

BACKGROUND/AIMS: Topical corticoids are used to treat irritant contact dermatitis (ICD) in humans. However, their clinical efficacy remains sub judice. This study was designed to assess the efficacy of low- and medium-potency corticosteroids on irritant dermatitis. METHODS: We induced an acute ICD via open application of sodium lauryl sulphate (SLS) on the hands of subjects. The dorsal side of hands was irritated with 10% SLS five times in one day. Once on day 1 and twice daily on days 2-5, 1% hydrocortisone, 0.1% betamethasone-17-valerate and vehicle cream (petrolatum) were applied subsequently. Visual grading, bioengineering techniques and squamometry were used to quantify skin response. RESULTS: Corticosteroids were found ineffective in treating the surfactant-induced irritant dermatitis when compared with the vehicle and with the untreated control. CONCLUSION: The counterintuitive result (in a relatively realistic and robust model) should be interpreted with caution until verified with other irritants of varying physicochemical properties.

Adult↗
PubMed2001

Commentary on "evidence that iron deficiency anemia causes reduced work capacity".

This commentary assesses the strength of the causal evidence presented by Haas and Brownlie in this supplement and examines the potential magnitude of iron-deficiency anemia on welfare. From both the laboratory and field experiments, the evidence is strong and suggests that the potential magnitude of the effect of iron-deficiency anemia on work productivity is substantial. This commentary briefly discusses some of the limitations of using the estimates of effects on physiological capacity for measuring the effect on the social and economic well-being of individuals and society. Biological data are relevant to social and economic development, but additional field studies may be as important as the laboratory experiments to answer questions that also affect work productivity, household maintenance and child raising activities, and hence affect social and economic development. We extend the critical evidence review of human field studies that received disproportionately less attention than the laboratory studies in Haas and Brownlie. We provide some estimates of the magnitude of effects on well-being based on how this information has been used. Future field studies that examine the effect of iron-deficiency anemia and work output in an economic sense should measure increases in productivity but should complement this information with data on wages, income or some measure of profits to derive a money metric measure of increased productivity. Additional information on individual time allocation in household work, child care and leisure may also be required to capture social benefits deriving from improved work capacity.

Anemia↗
PubMed2001

Prophylactic therapy with enoxaparin during L-asparaginase treatment in children with acute lymphoblastic leukemia.

Forty-one consecutive children with acute lymphoblastic leukemia (ALL) received prophylaxis therapy with the low molecular weight heparin (LMWH) enoxaparin during L-asparaginase treatment. Enoxaparin was given every 24 h subcutaneously at a median dose of 0.84 mg/kg per day (range, 0.45-1.33 mg/kg per day) starting at the first dose of L-asparaginase until 1 week after the last dose. Molecular analysis for thrombophilic polymorphisms documented prothrombin G20210A mutation in 3/27 (11%), homozygosity for MTHFR C677T mutation in 5/27 (18.5%, and heterozygosity for factor V Leiden mutation in 5/27 (18.5%) children. There were no thrombotic events during 76 courses of L-asparaginase in 41 patients who had received enoxaparin. One patient suffered brain infarct 7 days after enoxaparin was stopped. There were no bleeding episodes. In a historical control group of 50 ALL children who had not received prophylactic enoxaparin during L-asparaginase treatment, two had thromboembolisms (one deep vein thrombosis and one pulmonary embolism). Enoxaparin is safe and seems to be effective in prevention of thromboembolism in ALL patients during L-asparaginase therapy. This study provides pilot data for a future randomized trial of the use of LMWH during ALL therapy for the prevention of asparaginase-associated thrombotic events.

Adolescent↗
PubMed2000

An overview of the efficacy of topical corticosteroids in experimental human nickel contact dermatitis.

We review controlled trials of corticosteroid effect in experimentally elicited acute nickel contact dermatitis in man, in the hope of clarifying optimal efficacy for clinical use. To maximize discrimination and objectivity, we focus on data with 1 well-characterized allergen, nickel, in studies utilizing bioengineering documentation. Higher potency corticosteroids are effective (unlike in experimental irritant contact dermatitis), but optimum schedules still require definition.

Administration, Topical↗
PubMed1997

An empirical evaluation of eye movement desensitization and reprocessing (EMDR) with survivors of a natural disaster.

Controlled studies of treatments effective with victims of natural disasters are almost nonexistent. This is a small study conducted under difficult conditions to test the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) in treating trauma related reactions following Hurricane Andrew. The results were positive in that EMDR produced significant improvement over wait list controls in perceived posttraumatic avoidance behaviors and thoughts as measured by changes in the Impact of Event Scale and significant improvement in subjective aversive reactions to representative experiences of the hurricane. These results suggest and support other studies that EMDR can be an effective therapeutic intervention for trauma reactions.

Adaptation, Psychological↗
PubMed1980

Rheological properties of young and aged human erythrocytes.

Rheological properties were studied of young and old human erythrocytes from healthy adults. Viscosity measurements of packed erythrocyte suspensions as well as filtration of cells through polycarbonate sieves show that young cells are more flexible than aged ones. Since deformability of erythrocytes is the product of cell shape, flexibility of the membrane and fluidity of the intracellular hemoglobin, we studied the manner in which these factors are relevant to the diminished flexibility of aged erythrocytes. The biconcave cell shape is maintained during the process of aging. The viscosity of packed ghost suspensions from aged erythrocytes is increased versus that of young ones. The diminished flexibility of old ghosts correlates well with their smaller cell volume. The fluidity of the hemoglobin in the interior of the cells is decreased as indicated by an increased hemoglobin content of the isolated ghosts. We conclude that aged erythrocytes loose their deformability as a result of both a decreased fluidity of the intracellular hemoglobin and a diminished flexibility of the membrane.

Blood Viscosity↗
PubMed1975

Giant cell tumour of the sacrum. A case report.

A case is reported of a giant cell tumour of the sacrum, an infrequent but well-recorded site for this tumour. The relatively benign histology of this neoplasm was not consistent with its natural history in this patient, nor with its resistance to treatment. An additional feature of interest and concern was the intense vascularity of the lesion.

Adult↗
PubMedDate not supplied

Venous thromboembolism, factor V Leiden, and methylenetetrahydrofolate reductase in a sickle cell anemia patient.

Vaso-occlusive crisis is the most common cause of morbidity in patients with sickle cell anemia (SCA). Central nervous system involvement that leads to hemiplegia is the most frequent neurological complication in those patients. Peripheral deep venous thromboembolism was not reported in SCA patients. Activated protein C resistance is associated with an increased risk of thrombophilia. The authors report an SCA patient with recurrent cerebrovascular accident and deep venous thrombosis. Activated protein C resistance due to factor V Leiden heterozygous and heterozygocity for the methylenetetrahydrofolate reductase were diagnosed and suspected to be the risk factors that contribute to the development of the deep vein thrombosis in this SCA patient.

Activated Protein C Resistance↗
PubMedDate not supplied

Effect of hydroxyurea in sickle cell anemia: a clinical trial in children and teenagers with severe sickle cell anemia and sickle cell beta-thalassemia.

This study evaluated the efficacy of hydroxyurea treatment in the prevention of vaso-occlusive crises among children and teenagers with severe sickle cell anemia and sickle cell beta-thalassemia. Nineteen children and young adults with severe sickle cell disease were enrolled to the hydroxyurea treatment trial. The incidence of vaso-occlusive crises, acute chest syndrome, hemolytic crises, splenic sequestration episodes, blood transfusions, and hospital days in the 2 years before hydroxyurea (HU) treatment were compared with the same parameters in the first 2 years of treatment. The patients received a mean dose of 21.3 mg/kg/day daily and were treated during a mean period of 40.3 +/- 14 months (range 20 to 68 months). Significant increases were observed after 1 month in the Hgb, MCV, MCH, and MCHC levels and were more notable after 3 months. The increase in the Hgb F level became important after 3 months of HU therapy and was highly significant (p < .001) beyond 6 months. No differences were observed in the RDW, reticulocyte count, Hgb S, and Hgb A2. Severe neutropenia was observed in one case. A decrease in the frequency of vaso-occlusive crises, acute chest syndrome, hemolytic crises, blood transfusions, and days spent in the hospital was demonstrated during the HU treatment period compared to the same period before. The clinical and laboratory response to HU was dramatic in severely affected sickle cell anemia (SCA) patients. The response to HU in children and teenagers with severe sickle cell anemia is similar to the response in adults, and no severe adverse effects were observed.

Adolescent↗
PubMedDate not supplied

Legg-Calvé-Perthes disease, protein C deficiency, and beta-thalassemia major: report of two cases.

Legg-Calvé-Perthes disease is an idiopathic osteonecrosis or avascular necrosis of the capital femoral epiphysis and the associated complications thereof occurring in an immature growing child. The association between osteonecrosis of the femoral head and thrombophilia was postulated by Glueck in 1994. We describe Legg-Calvé-Perthes disease associated with protein C deficiency and beta-thalassemia major in two children among a cohort of 79 beta-thalassemia patients treated in our clinic. The association of thrombophilia, aseptic necrosis of the femoral head, and beta-thalassemia has not been previously described in the literature.

Adolescent↗