Biomedical subjects
Publications and source records attributed to D S Skrabalak.
Facial swelling in a dog was found to be associated with a supernumerary premolar. Extraction of the tooth alleviated the swelling. Although supernumerary teeth are common, they are not known to be associated with facial swelling.
Equine neutrophils (PMN) were isolated from citrated normal blood by density gradient separation on Ficoll-Hypaque to greater than 96% purity and 98% viability and an average of 3.78 x 10(7) PMN/ml. The agonist C5a des Arg was used in serial dilutions of whole zymosan-activated equine plasma (ZAP) or was partially purified from ZAP by column chromatography. Purified equine PMN exhibited rapid aggregation following incubation with C5a des Arg which was further dependent on the availability of divalent cations, especially Mg++. The microfilament disruptive agent cytochalasin B (5 micrograms/50 microliters) greatly augmented aggregation responses to C5a des Arg. Subaggregating doses of C5a des Arg promoted PMN adhesiveness as assayed on 0.5 x 10 cm borosilicate glass columns containing a 2.0 cm bed of Sephadex G-25. This C5a des Arg-induced increased adhesiveness was inhibitable by prior incubation of the PMN with either non-steroidal (0.065 M phenylbutazone) or steroidal (0.005 M dexamethasone) anti-inflammatory agents. Ultrastructural studies correlated well with functional assays and revealed marked organelle-free lamellipodia formation without PMN-PMN contact at subaggregating doses of the agonist and progressive PMN-PMN contact at aggregating doses. Equine PMN are responsive to C5a des Arg, and induced adhesiveness responses can be manipulated by anti-inflammatory agents.
Betamethasone and its major unconjugated metabolite, 6-beta-hydroxybetamethasone, were detected in equine urine by thin-layer chromatography and characterized by micro-liquid chromatography/mass spectrometry (micro-LC/MS). Their structures were confirmed by a combination of infrared spectroscopy and nuclear magnetic resonance spectroscopy.
Micro-liquid chromatography-mass spectrometry (micro-LC-MS) was utilized to quantitatively determine betamethasone and its major unconjugated metabolite, 6 beta-hydroxybetamethasone, in equine plasma and urine. The advantage of micro-LC-MS over conventional gas chromatography-mass spectrometry in corticosteroid determination is illustrated and the reliable, steadfast nature of micro-LC-MS is demonstrated through example.
Several important corticosteroids were qualitatively determined in the plasma and urine of horses by micro-liquid chromatography-mass spectrometry (micro-LC-MS). The sensitivity and specificity of micro-LC-MS are demonstrated as is the ability of micro-LC-MS to deal with endogenous interferences. In turn, the relative amount of dexamethasone and its major unconjugated metabolite were determined in equine urine by micro-LC-MS; the conclusions drawn are reported.
The toxic effects of dichloromethane (DCM) are reviewed. Human dose-response data, tolerance levels, and the effects of physical exercise and smoking on DCM toxicity are reported. Finally, occupational exposure, current NIOSH (1976) recommendations, and the consequences of ill-health as they pertain to DCM in the workplace are discussed.
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Radiolabeled dexamethasone (9-fluoro-16 alpha-methyl-11 beta, 17, 21-trihydroxy-1,4-pregnadiene-3,20-dione) was utilized to develop a practical and relatively expedient method of detection for dexamethasone and its major metabolite in horse urine. The effects of solvent, pH, salt saturation, and back extraction on the extraction efficiency of dexamethasone-related compounds and the presence of endogenous background were evaluated. Final isolations of dexamethasone and its major urinary metabolite were procured by successive thin-layer chromatography (TLC) in three different developing systems.
We describe an integrated micro-liquid chromatograph/mass spectrometer (micro-LC/MS) system capable of performing routine determinations for 1--10 ng of drugs and their metabolites extracted from biological fluids. The micro-LC is constructed from conventional "high-performance" liquid-chromatographic instrumentation by using commercially available components. The mass spectrometer is operated in the chemical ionization mode. The direct liquid introduction micro-LC/MS interface can be constructed from commercially available materials. Chromatographic and mass spectral results demonstrate the ability of the micro-LC and micro-LC/MS system to separate and determine multiple components in standards of trace concentrations and in equine urinary extracts. The stability and sensitivity of this micro-LC/MS system are demonstrated through determinations of trichlormethiazide.