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Biomedical subjects

J W Carpenter

Publications and source records attributed to J W Carpenter.

At least 55 records · Page 3Linked to original sources

Pharmacokinetics of gentamicin in blood plasma of quail, pheasants, and cranes.

Rate of appearance, peak concentration, and the biological half-life of gentamicin in the plasma of quail (Coturnix coturnix), pheasants (Phasianus colchicus), and cranes (Grus canadensis tabida) were studied. Gentamicin was given IM in doses of 5, 10, and 20 mg/kg of body weight. Peak plasma concentrations occurred earliest in the quail, latest in the cranes. The peak concentrations varied directly with the administered doses in all species. The biological half-life of gentamicin was 42 +/- 12 minutes in the quail, 75 +/- 15 minutes in the pheasants, and 165 +/- 37 minutes in the cranes. On the basis of the present data, dosage regimens for gentaminic of 5 mg/kg every 8 hours in pheasants and cranes, and 10 mg/kg every 6 hours in quail, would be expected to give constant plasma concentrations greater than 4.0 micrograms/ml.

Animals↗

Coccidia of whooping cranes.

Coccidial oocysts were observed in 6 of 19 fecal samples from free-ranging whooping cranes (Grus americana) and 4 of 16 samples from captive whooping cranes. Eimeria gruis occurred in four free-ranging whooping cranes and E. reichenowi in two free-ranging and two captive whooping cranes. Fecal samples from two captive cranes contained oocysts of Isospora lacazei which was considered a spurious parasite. Oocysts of both species of Eimeria were prevalent in fecal samples collected from three free-ranging Canadian sandhill cranes (G. canadensis rowani) from whooping crane wintering grounds in Texas. These coccidia were prevalent also in fecal samples from 14 sandhill cranes (of 4 subspecies) maintained in captivity at the Patuxent Wildlife Research Center in Maryland.

Animals↗

Diabetes mellitus in a black-footed ferret.

Diabetes mellitus was tentatively diagnosed in a black-footed ferret with polyuria, polydipsia, polyphagia, dehydration, and weight loss. Laboratory findings (marked hyperglycemia (724 mg/100 ml), glycosuria, and ketonuria) and the subsequent favorable response to insulin therapy confirmed the diagnosis. Although lesions were not observed in the pancreas, gross and histologic findings concomitant with diabetes mellitus included arteriosclerosis, with calcification of the aorta and other major vessels; mild necrotizing hepatitis; and mild proliferative glomerulonephritis. A perineal adenocarcinoma, with metastasis to an internal iliac lymph node, was an incidental finding. Special stains demonstrated adequate numbers of beta cell granules in the islets of Langerhans. Thus, the diabetes was apparently due to a lack of release of the synthesized insulin or to diminished effectiveness of the secreted insulin.

Adenocarcinoma↗

Suspected lead toxicosis in a bald eagle.

An immature bald eagle (Haliaeetus leucocephalus) was submitted to the University of Maryland, College Park, for clinical examination. The bird was thin, had green watery feces, and was unable to maintain itself in upright posture. Following radiography, the bird went into respiratory distress and died. Numerous lead shot were recovered from the gizzard, and chemical analysis of liver and kidney tissue revealed 22.9 and 11.3 ppm lead, respectively. The clinical signs, necropsy findings, and chemical analysis of the eagle were compatible with lead toxicosis.

Animals↗

Fatal vaccine-induced canine distemper virus infection in black-footed ferrets.

Four black-footed ferrets that were live-trapped in South Dakota and transported to the Patuxent Wildlife Research Center died within 21 days after vaccination with modified live canine distemper virus. Immunofluorescence, European ferret inoculation, virus isolation attempts, and serum-neutralization tests indicated insufficient attenuation of the vaccine for this species.

Animals↗

Growth inhibitory and arginase activities in liver and hepatoma extracts.

The growth-inhibitory activity against H.Ep. No 2 cells observed in phosphate buffer extracts of rat liver appears to be due to the enzyme, arginase. This conclusion is based on the findings that (1) extracts of hepatomas containing lower levels of the enzyme also contain less inhibitory activity; (2) partial purification of the inhibitory factor results in a similar purification of the enzyme; (3) molecular weights of the enzyme and of the inhibitory factor are similar; and (4) various treatments alter the enzyme and inhibitory activities similarly.

Animals↗

Hemoprotozoa in mourning doves and other small birds of western Oklahoma.

Blood smears obtained from 370 birds live-trapped in western Oklahoma were examined for hemoprotozoa. Haemoproteus spp. were found in 189 (90.4%) mourning doves (Zenaida macroura), one oriole (Icterus galbula), two mockingbirds (Mimus polyglottos), and three brown thrashers (Toxostoma rufum). Plasmodium sp. was present in one brown thrasher. Haemoproteus spp. in the mourning dove were identified as H. sacharovi and H. maccallumi, with the latter species predominating. The average parasitemia for doves infected only with H. sacharovi was 0.1% of the erythrocytes, for doves infected only with H. maccallumi it was 0.9%, and in doves with dual infections 1.8% of the erythrocytes were infected.

Animals↗

Mechanisms of action of 6-thioguanine, 6-mercaptopurine, and 8-azaguanine.

The effects of 6-thioguanine on purine biosynthesis and cell viability have been examined in H.Ep. 2 cells grown in culture. Toxicity is not reversed by aminoimidazolecarboxamide, suggesting that inhibition of purine biosynthesis de novo is not the sole mechanism of toxicity. Also, 6-(methylmercapto)purine ribonucleoside, a potent inhibitor of purine biosynthesis de novo, produces more marked reductions in cellular pools of purines than does 6-thioguanine without killing cells. There is no apparent inhibition by 6-thioguanosine 5'-monophosphate of other enzymes leading to the synthesis of guanosine 5'-triphosphate as determined in whole cells by measurements of radioactive hypoxanthine or guanine incorporation. Inhibition of DNA synthesis by 1 mM thymidine protects cells from 6-mercaptopurine or 6-thioguanine but fails to protect cells from 8-azaguanine toxicity. On the other hand, inhibition of RNA synthesis by 6-azauridine plus deoxycytidine protects cells against 8-azaguanine but does not protect against 6-thioguanine or 6-mercaptopurine toxicity. In agreement with the in vitro data, arabinosylcytosine (a potent inhibitor of DNA synthesis) fails to protect mice against 8-azaguanine but has previously been shown to protect mice from 6-mercaptopurine or 6-thioguanine toxicity. The results support the hypotheses of others that incorporation into DNA (as 6-thioguanine nucleotide) is a mechanism of toxicity for these thiopurines, whereas 8-azaguanine is toxic due to its incorporation into RNA.

Azaguanine↗

Scintigraphic assessment of distal extremity perfusion in 17 patients.

To assess the role of scintigraphic evaluation of distal limb perfusion, the medical records and scintigraphic perfusion images of 17 animals (8 dogs, 2 cats, 2 calves, 4 birds and 1 ferret) with clinical signs of distal limb ischemia were examined retrospectively. Images were obtained at 5 and 10 minutes following injection of 99mTc-MDP, or 99mTc-DTPA. The initial scintigraphic diagnoses of 17 animals included complete ischemia (8/17), partially reduced perfusion (5/17), and normal to increased perfusion (4/17). In 4 of the animals with partially reduced perfusion, follow-up scans indicated progression to complete ischemia (1/4) or normal to increased perfusion (3/4). Nine of 17 animals had a final scintigraphic diagnosis of complete distal limb ischemia, and these animals were either euthanized (5/9) or had limb amputation (4/9). A final diagnosis of complete ischemia was supported with either repeat scanning (3/10), continued clinical observation (6/10) and/or pathological examination (10/10). Clinical signs of ischemia resolved in all (7/17) animals with increased or normal perfusion on their final scan. Scintigraphy provided a safe and noninvasive assessment of distal limb perfusion, which corresponded with clinical outcome.

Amputation, Surgical↗