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A D Mitchell

Publications and source records attributed to A D Mitchell.

88 records · Page 5Linked to original sources
PubMed1975

A simple and rapid method for the preparation of adenosine triphosphatase from submitochondrial particles.

An almost pure form of the bovine heart mitochondrial adenosine triphosphatase (ATPase) is released from the membrane by shaking submitochondrial particles with chloroform. Analyses on polyacrylamide gels and by electron microscopy, and also sensitivity to inhibitors, show that the chloroform-released enzyme is similar to other ATPase preparations from bovine heart mitochondria.

Adenosine Triphosphatases↗
PubMed1965

Prapism.

Explore the source record for details and available documents.

Aged↗
PubMedDate not supplied

Body composition analysis of pigs from 5 to 97 kg by dual energy X-ray absorptiometry.

A total of 231 pigs were anesthetized and then scanned by DXA using a Lunar DPXL instrument. The weight of the pigs ranged from 5 to 97 kg (av. = 37.7 kg). Of the total, 98 pigs were scanned using the pediatric mode and 133 pigs were scanned using the adult mode. After scanning, the pigs were euthanized, the entire body homogenized by grinding, and analyzed chemically for fat, water, protein and total body mineral content. The mean value for the DXA total tissue mass (37.1 kg) was not significantly (P > 0.05, n = 231) different from the mean body weight. The mean DXA value for percent fat was 14.6 and was significantly less (P < 0.05) than the mean value (17.6%) measured by CHEM analysis. The greatest discrepancy occurred in pigs with < 15% body fat. From a prediction equation using the DXA R value [% fat = 493-349(DXA R value)], the DXA estimated percent fat was 18.0%, compared to 17.6% by CHEM analysis (P > 0.05). Using a prediction equation [g protein = -1.062 + 0.22(g DXA lean)], the DXA estimate for body protein content was 17.8%, compared to 17.1% (P < 0.05, n = 131) by CHEM analysis. The DXA estimate for body water content [g water = 508 + 0.74 (g DXA lean)] was 63.8%, compared to 62.6% (P < 0.05, n = 231) by CHEM analysis. The bone mineral content of 83 of the pigs measured by DXA was 2.40%, compared to 2.54% (P < 0.05, n = 83) estimated from CHEM analysis of total body ash [g bone mineral = g total body ash -0.0085(g DXA lean)].

Absorptiometry, Photon↗
PubMedDate not supplied

Steady state kinetics of 14C-sulfamethazine [4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzene[U-14C]sulfonamide] metabolism in swine.

Swine were dosed orally with 14C-sulfamethazine [4-amino-N-(4, 6-dimethyl-2-pyrimidinyl)benzene[U-14C]sulfonamide] for 3, 5, or 7 days (two 165-mg doses/day; 0.46 muCi/mg) and killed 8 hr after the last dose. The concentration of carbon-14 in the tissues increased by an average of 21% from day 3 to day 5 of dosing. However, there was no further increase from day 5 to day 7, indicating that a steady state level of carbon-14 in the tissues was attained by dosing on 5 consecutive days. Liver, kidney, skeletal muscle, blood, and adipose tissue from all animals were analyzed for 14C-labeled sulfamethazine, N4-acetylsulfamethazine, desaminosulfamethazine [N-(4, 6-dimethyl-2-pyrimidinyl)benzenesulfonamide], and the N4-glucose conjugate of sulfamethazine. The identity of these compounds (the hydrolysis product of N4-glucose conjugate) was confirmed by HLPC and gas-liquid chromatography/mass spectral analysis after methylation. The relative distribution of 14C-sulfamethazine and these metabolites varied somewhat among the tissues analyzed but did not vary within a tissue after different periods of dosing.

Adipose Tissue↗
PubMedDate not supplied

Depletion kinetics of 14C-sulfamethazine [4-amino-N-(4, 6-dimethyl-2-pyrimidinyl)benzene[U-14C]sulfonamide] metabolism in swine.

Swine weighing 60-70 kg were orally administered 14C-sulfamethazine [4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzene[U-14C]sulfonamide] at 12-hr intervals for 7 days (165 mg/dose; 0.126-5.04 mCi/mmol). The animals were sacrificed at 8 hr or 2, 5, or 10 days after the last dose was given and tissues were assayed for total 14C activity. The presence of 14C-labeled sulfamethazine, N4-acetylsulfamethazine, desaminosulfamethazine, and the N4-glucose conjugate of sulfamethazine in blood, liver, kidney, skeletal muscle, and adipose tissue was verified by HPLC and GC-MS analysis. Total 14C residue levels in all tissues examined had dropped to less than 0.1 ppm sulfamethazine equivalents by day 10 of the depletion period. The mean half-life (t1/2) for sulfamethazine, the N4-glucose conjugate of sulfamethazine, and N4-acetylsulfamethazine was estimated to be 0.8 day. In some tissues, the depletion of the N4-glucose conjugate of sulfamethazine and N4-acetylsulfamethazine had decreased significantly between days 5 and 10, resulting in an approximate doubling of the t1/2 for that period. In contrast, the half-life of desaminosulfamethazine varied from a mean of 0.96 day during the 8-hr-5-day depletion period to 3.7-9.1 days during the 5- 10-day depletion period. In most tissues, the t1/2 for the 14C-activity in the methanol-insoluble fraction increased by 3-5-fold between days 5 and 10 of the depletion period. No predictable relationship was observed between blood sulfamethazine or metabolite levels and total residue levels in the tissues.

Adipose Tissue↗
PubMedDate not supplied

Identification and quantitation of sulfamethazine metabolites by liquid chromatography and gas chromatography-mass spectrometry.

Methods for the identification and quantitation of carbon-14 labeled sulfamethazine [4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzenesulfonamide], N4-acetylsulfamethazine, the N4-glucose conjugate of sulfamethazine, and desaminosulfamethazine in swine tissue are described. Tissues are ground and extracted with methanol, and the 14C-labeled compounds are purified by XAD-2 column chromatography and C-18 reverse phase liquid chromatography (LC) and the 14C-labeled compounds are then methylated and identified by gas chromatography-mass spectrometry analysis. Quantitation is accomplished by measuring the amount of 14C-activity that cochromatographs (C-18 reverse phase LC) with reference compounds.

Animals↗