Search PubMed⌕ Search

Biomedical subjects

P Mushak

Publications and source records attributed to P Mushak.

At least 55 records · Page 3Linked to original sources
PubMed1978

Lead exposure during infancy permanently increases lithium-induced polydipsia.

Lead (200 milligrams per kilogram) was administered daily by intubation to Long-Evans rats on days 3 through 30 of life. Thirty to 180 days after cessation of lead administration, the lead-treated rats were consistently more polydipsic after lithium administration (2 millimoles per kilogram per day) than were pair-treated controls. Lithium increased the plasma renin activity equally in both the lead treated and the control groups. These data are evidence that there may be permanent neural changes induced by postnatal exposure to lead that are manifested by pharmacological challenge with lithium.

Animals↗
PubMed1977

Flameless atomic absorption (FAA) and gas-liquid chromatographic studies in arsenic bioanalysis.

Procedures for assessment of arsenic in soft tissue by use of flameless atomic absorption (FAA) and gas-liquid chromatography (GLC), have been evolved, with special emphasis on the analytical distinction among inorganic, monomethyl-, and dimethylarsenic in several oxidation states. The chemical bases for such speciation reside in several properties of the arsenicals under consideration: (1) pentavalent inorganic arsenic, methylarsonic, and cacodylic acid are not extracted from tissue matter made strongly acid with hydrochloric acid, while the corresponding trivalent forms (as halides) are extracted; (2) chloroform extracts of samples treated under reducing conditions (HCl-KI) retain organoarsenicals when these extracts are re-extracted with water, but do not when aqueous solutions of oxidants are employed; (3) reduced cacodylate (dimethylarsinous acid) is not detected in the graphite furnace of an FAA unit under conditions selected, while cacodylate can be so detected. For GLC studies, monomethyl- and dimethylarsenic are simultaneously measured as the diethyldithiocarbamate complexes with an instrument equipped for electron-capture detection and containing a glass column packed with silanized 5% OV-17 on Anakrom A.S.

Animals↗
PubMed1975

Blood-brain barrier dysfunction in acute lead encephalopathy: a reappraisal.

Acute lead encephalopathy was induced in adult guinea pigs by administering daily oral doses of lead carbonate. During the development of the encephalopathy, the structural and functional integrity of the blood-brain barrier was evaluated with electron microscopy and tracer probes. Blood, cerebral gray matter, liver, and kidney were analyzed for lead, calcium, and magnesium content. The animals regularly developed an encephalopathy after four doses of lead. There were no discernible pathomorphologic alterations in the cerebral capillaries or perivascular glial sheaths. Furthermore, no evidence of blood-brain barrier dysfunction was demonstrated with Evans blue-albumin complex or horseradish peroxidase. Blood-brain barrier permeability to radiolead was not increased in the intoxicated animals. During the development of the encephalopathy there was a progressive rise in the lead concentration in all tissues. Concurrently, there was a significant rise in brain calcium. These results suggest that the encephalopathic effects of lead may be mediated directly at the neuronal level.

Animals↗
PubMed1970

Electron spin resonance studies of carbonic anhydrase: transition metal ions and spin-labeled sulfonamides.

Electron spin resonance (esr) spectra of Cu(II) and Co(II) carbonic anhydrase, and a spin-labeled sulfonamide complex of the Zn(II) enzyme, are reported. The coordination geometry of Cu(II) bound in the enzyme appears to have approximately axial symmetry. Esr spectra of enzyme complexes with metal-binding anions also show axial symmetry and greater covalency, in the order ethoxzolamide < SH(-) < N(3) (-) </= CN(-). Well-resolved superhyperfine structure in the spectrum of the cyanide complex suggests the presence of two, and probably three, equivalent nitrogen ligands from the protein. Esr spectra of the Co(II) enzyme and its complexes show two types of Co(II) environment, one typical of the native enzyme and the 1:1 CN(-) complex, and one typical of a 2:1 CN(-) complex. Co(II) in the 2:1 complex appears to be low-spin and probably has a coordination number of 5. Binding of a spin-labeled sulfonamide to the active center immobilizes the free radical. The similarity of the esr spectra of spin-labeled Zn(II) and Co(II) carbonic anhydrases suggests that the conformation at the active center is similar in the two metal derivatives.

Binding Sites↗
PubMedDate not supplied

Quantitative analysis of ethyltin compounds in mammalian tissue using HPLC/FAAS.

Measurement of total tin and ethyln tin forms in mammalian tissue is described, using ion-exchange high performance liquid chromatography (HPLC) in tandem with flameless atomic absorption spectrometry (FAAS) for tin-specific detection. All tin forms in whole blood and tissue homogenates were liberated from biological (in vivo) binding by treatment with 6M hydrochloric acid for a period of 4 hr. Ethyln tin species, as the chlorides, were partitioned into chloroform:ethyl acetate (1:1) and analyzed via HPLC using a strong cation exchange column, with fraction collection by a programmable collector and fraction tin measurement by FAAS. Triethyl- and diethyltin were separated and quantitated using 0.167M ammonium citrate in 70:30 methanol:water, while monoethyltin required the use of 0.50M citrate salt in 70:30 water:methanol as mobile phase to effect elution. The difference between total and speciated tin content provides an estimate of remaining tin species, including the inorganic element.

Animals↗