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Biomedical subjects

M Lewin

Publications and source records attributed to M Lewin.

88 records · Page 5Linked to original sources
PubMedDate not supplied

Separation of glutaraldehyde and some of its aldol condensation products by hydroxyl-aldehyde group affinity chromatography.

Glutaraldehyde exists in aqueous solution in equilibrium with monomers and polymers of cyclic and open-chain hemialdals and hydrates. At alkaline pH oligomeric and polymeric alpha,beta-unsaturated aldehyde derivatives are formed from primarily produced aldol condensation products. This communication reports a method for separation of such aldol condensates by means of a new high performance liquid chromatography technique based on the affinity of aldehyde groups for hydroxyl groups of a hydroxylated polyether matrix (Bio-Gel SEC-10). Five peaks corresponding to different aldol condensates of glutaraldehyde were obtained from the affinity column. They have been distinguished by 1H-NMR and UV spectroscopy. Kinetic measurements yielded formation rates for the different aldol condensates.

Alcohols↗
PubMedDate not supplied

Dioxin exposure in a residential community.

The Agency for Toxic Substances and Disease Registry (ATSDR) conducted biological testing to assess dioxin exposure in residents of a community who lived in an area with heavy chemical industry. Dioxin concentrations were measured in blood serum samples from 28 adult residents of the community. Fourteen of those tested had blood dioxin concentrations that exceeded the 95th percentile prediction level of an age-matched comparison population. Specific congener analyses indicated that the elevated dioxin concentrations were primarily due to high concentrations of 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), 1,2,3,7,8 pentachlorodibenzo-p-dioxin (PeCDD), and hexachlorodibenzo-p-dioxins (HxCDs). Principal components analysis (PCA) indicated that the profiles of dioxin congeners were different in people with elevated blood dioxin concentrations compared to those with background concentrations. Elevated blood dioxin concentrations were detected only in older members of the population, which suggests that dioxin exposures were higher in the past. The sources of the dioxin exposure have not been identified.

Adult↗
PubMedDate not supplied

Anticoagulation in cerebral ischemia.

Anticoagulation clearly benefits patients at risk of stroke from cerebral embolism. Conversely, patients with completed ischemic stroke are not benefited, and may show a higher mortality and morbidity because of hemorrhagic complications. Technical advances in the early, accurate diagnosis of cerebral hemorrhage, the constant infusion of heparin, and closer monitoring of anticoagulation have continued to reduce the risk of hemorrhage in treated patients. In patients with TIA, alternative therapy with anti-platelet agents, which appears to prevent stroke at less bleeding risk, is under study. Current results show no differences between the two therapies, but only historical controls are available for evaluation of benefit. Whether or not anticoagulation prevents progression of neurologic deficit in patients with strokes-in-evolution remains an unanswered question, which can be resolved only by prospective, randomized, controlled trials.

Aged↗
PubMedDate not supplied

Essential mixed cryoglobulinemia type II.

We report a rare case of essential mixed cryoglobulinemia type II with membrano-proliferative glomerulonephritis (MPGN) type I in which HCV was not found. Long-term history of palindromic rheumatism, skin leukocytoclastic vasculitis attacks and micro-normocytic anemia preceded the appearance of cryoglobulinemia. Cryoprecipitate consisted of monoclonal IgMk-RF and polyclonal IgG (essential mixed type II). The newly appreciated cryoglobulinemia was associated with Coombs positive hemolytic anemia. The MPGN in this case had a benign course and responded to complex simple therapies including prevention of exposure to cold, low antigen content diet, treatment of provoking factors such as UTI, and maximal dose of ACE inhibitor. Responsiveness of skin vasculitis to colchicine therapy was restored after a two-month colchicine withdrawal period and therefore corticosteroid and immunosuppressive therapy was postponed.

Aged↗