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Biomedical subjects

K A Pittman

Publications and source records attributed to K A Pittman.

At least 73 records · Page 4Linked to original sources
PubMed1980

Placental transfer and other physiologic studies with intravenous butorphanol in the anesthetized pregnant ewe.

In clinical evaluation, butorphanol has been used in labor pain with analgesia and newborn outcome comparable to meperidine. Only limited placental transfer studies have been done in the human. The placental transfer and effect of intravenous butorphanol (2 mg) on avrious cardiovascular parameters were determined in anesthetized sheep. Serum butorphanol was determined by a specific radioimmunoassay. Butorphanol 2 mg intravenously did not affect the measured cardiovascular parameters in either ewe or fetus. Butorphanol could be demonstrated in the fetal circulation within one minute of administration and appeared to reach equilibrium in the maternal circulation rapidly and to remain in equilibrium thereafter. A biexponential decline of butorphanol was observed in the maternal serum with a terminal elimination half-life of 50 minutes. The data suggest butorphanol distribution in the pregment ewe can be conceptualized by the two compartment model, with the fetus as part of the peripheral compartment. These studies support the clinical finding from other studies that butorphanol appears to be a safe analgesic for use in labor pain.

Anesthesia↗
PubMed1978

Environmental chemical-induced immune dysfunction.

Antibody formation, endotoxin sensitivity, and resistance to a challenge malarial infection were evaluated in mice fed a diet containing polychlorinated biphenyl (PCB) (Aroclor 1242) or hexachlorobenzene (HCB). Antibody synthesis to the antigen sheep RBC (SRBC) was significantly depressed in the PCB- and HCB-treated (167 ppm) animals as evidenced by the fact that control mice elicited an approximate twofold increase in antibody formation over the chemical-treated mice. Serum IgA concentrations in the PCB- and HCB-treated mice were consistently 40--80 mg/dl lower than control values. Gram-negative endotoxin (Salmonella typhosa) sensitivity in PCB- and HCB-treated mice was increased 5.2- and 32-fold, respectively, following the dietary administration of 167 ppm of Aroclor 1242 or HCB for 6 weeks. An endotoxin hypersusceptibility was also noted at 3 weeks after dietary administration. Decreased resistance to a malaria challenge was also demonstrated in the xenobiotic-treated mice. A 20% decrease in mean survival time of mice fed Aroclor 1242 for 3 to 6 weeks and inoculated with Plasmodium berghei (NYU-2) was observed. Infected mice which had received HCB for 3 or 6 weeks manifested reductions in mean survival time of 24 and 31%, respectively. The data indicated that environmental chemical contaminants impair host resistance and, since no concomitant histopathological alterations were observed in the treated mice, the evaluation of immune parameters may possibly be a sensitive indicator of toxicity.

Animals↗
PubMed1978

Impaired host resistance to endotoxin and malaria in polychlorinated biphenyl- and hexachlorobenzene-treated mice.

The in vivo effect of polychlorinated biphenyl (PCB) and hexachlorobenzene (HCB) on murine endotoxin sensitivity and resistance to malaria (Plasmodium berghei NYU-2) infection was studied. The dietary administration of 167 ppm (167 microgram/g) of PCB 1242 or HCB for 3 weeks resulted in an enhanced sensitivity to gram-negative endotoxin (Salmonella typhosa), which was further increased in animals maintained on the diets for 6 weeks. By 6 weeks, a 5.2- or 32-fold increase in endotoxin sensitivity was seen in mice fed PCB or HCB, respectively. A 20% decrease in mean survival time of mice fed PCB 1242 for 3 or 6 weeks and inoculated with malaria was demonstrated. Infected mice that received HCB for 3 or 6 weeks manifested a reduction in mean survival time of 24 or 31%, respectively. Histopathological examination revealed a normal thymus, spleen, mesenteric lymph nodes, and lungs. Centrilobular and pericentral hepatocyte hypertrophy, common to organochlorine exposure, was observed. Electron capture gas chromatographic analysis for PCB 1242 or HCB in the tissues examined histologically revealed a significant deposit of the xenobiotics. HCB concentration was approximately 16 to 25 times greater than that of PCB. The data indicate that environmental chemicals impair host resistance and that the alteration may be related to the presence of the chemicals in the lymphoreticular organs.

Animals↗
PubMed1976

Gas-liquid chromatographic determination of azinphos ethyl in human plasma and in mouse plasma, tissue, and fat.

A new method for the determination of azinphos ethyl (O,O-diethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate) in human plasma and in mouse plasma, tissue, and fat has been developed. The method is based on extraction with benzene or hexane and cleanup of fat and tissue samples by a minicolumn containing Florisil and sodium sulfate. Azinphos ethyl is eluted from the column with 10% acetonitrile in benzene and is concentrated to an appropriate volume for gas-liquid chromatographic analysis, using a 63Ni electron capture detector and a glass column containing 3% OV-1 on Gas-Chrom Q. The method is sensitive to 0.005 ppm in human plasma, 0.01 ppm in mouse plasma, 0.08 ppm in mouse liver, 0.05 ppm in mouse brain, and 0.10 ppm in mouse fat. The limit of detection is 2 pg; mean recoveries ranged from 96 to 98%.

Adipose Tissue↗
PubMed1967

Oligopeptide uptake by Bacteroides ruminicola.

Bacteroides ruminicola did not take up (14)C from exogenous (14)C-labeled l-proline or (14)C-labeled l-glutamic acid and took up very little (14)C from exogenous (14)C-labeled l-valine. Growing cultures of B. ruminicola rapidly took up (14)C from (14)C-proline-labeled peptides of molecular weights up to 2,000 and incorporated it into trichloroacetic acid-insoluble cell material. Uptake and incorporation did not occur at 0 C and were reduced or eliminated in glucose-starved cells, depending upon the length of time the cells were starved. The initial rate of uptake of peptides seemed to exhibit saturation kinetics, but it was impossible to establish this conclusively. The initial uptake of (14)C from peptides was not affected by chloramphenicol but the incorporation of it into trichloroacetic acid-insoluble cell material was virtually eliminated. Only moderate amounts of trichloroacetic acid-extractable, labeled material were present in cells during peptide uptake, whether or not chloramphenicol was present. (14)C-proline was rapidly released from labeled peptides during uptake, whether or not chloramphenicol was present. The amount of (14)C fixed into trichloroacetic acid-insoluble cell material was directly related to the size of peptides originally supplied in the medium. It is concluded that B. ruminicola possesses a general system for the uptake of peptides, that peptides are rapidly hydrolyzed during or after uptake, and that oligopeptides function only to supply amino acids in a form available to the organism.

Bacteria↗
PubMedDate not supplied

Evaluation of two new megestrol acetate tablet formulations in humans.

The bioequivalence of two new investigational 160 mg tablets, one containing the regular form and the other a micronized form of megestrol acetate, was determined relative to a commercially available 40 mg tablet (Megace). The tablets were administered to 24 male subjects in a three-way cross-over study, balanced for sequence, with a week between administrations. The 40 mg tablets were administered q.i.d. at 08.00, 12.00, 18.00 and 22.00 h, while the 160 mg tablets were administered once at 08.00 h. Plasma samples were collected at appropriate times out to 96 h after administration and were analysed for megestrol acetate with a validated high performance liquid chromatographic procedure. Based on the times to maximum plasma concentrations (2.5 to 2.8 h), the absorption rate constant was the same for each of the tablets. Relative to the 40 mg q.i.d. dose, the 160 mg regular and the 160 mg micronized tablets had mean relative bioavailabilities of 97 per cent and 118 per cent, respectively.

Adult↗