PubMed Health⌕ Search

Biomedical subjects

L Roth

Publications and source records attributed to L Roth.

At least 73 records · Page 4Linked to original sources
PubMed1986

Scintigraphic diagnosis of primary hepatocellular carcinoma in the woodchuck (Marmota monax).

Hepatic imaging with 99mTc-sulfur colloid was used to diagnose primary hepatocellular carcinoma (PHC) in woodchucks infected with woodchuck hepatitis virus (WHV). Based on imaging results, 6 of 12 WHV-infected woodchucks had space-occupying hepatic lesions, and all 6 had PHC. Of the remaining woodchucks, 2 did not have PHC, 2 had discrete tumors (less than 1 cm diameter), 1 had miliary small tumors, and 1 had tumors located near the great vessels. Hepatic imaging was a valuable technique for diagnosis of PHC in WHV-infected woodchucks.

Animals↗
PubMed1986

Light microscopic and electron microscopic changes in the livers of cats with extrahepatic bile duct obstruction.

Light microscopic and transmission electron microscopic changes were studied in the livers of 6 cats at 25 to 54 days after their extrahepatic bile ducts were experimentally obstructed. Histologic findings included various degrees of bile duct dilatation, ductular proliferation, and peribiliary fibrosis. Concentric layers of dense, birefringent connective tissue surrounded midsized bile ducts. The degrees of bile duct proliferation, hepatocellular degeneration, and bile retention were similar in each cat, but the amount of periductular connective tissue increased with chronicity of bile duct obstruction. Ultrastructural changes included marked swelling of endoplasmic reticulum and mitochondrial inner compartments, marked dilatation and distention of the canaliculi by bile casts, and numerical reduction of canalicular microvilli. Microvilli were often swollen and blunt. Mitochondria were swollen and long, and the cristae lacked normal distribution and density. Cytoplasmic accumulations of granular, electron-dense material and concentrically laminated arrays of material indicative of bile substances were also observed.

Animals↗
PubMed1985

Chronic hepatitis and hepatocellular carcinoma associated with persistent woodchuck hepatitis virus infection.

The livers of 16 woodchucks with naturally acquired chronic infection with woodchuck hepatitis virus were examined both grossly and histologically in 14 biopsy specimens and seven necropsy specimens. Fifteen woodchucks had lesions characteristic of chronic hepatitis; ten of these had chronic active hepatitis, four had chronic persistent hepatitis, and one had cirrhosis with nodular regeneration. In one woodchuck there was massive hepatic necrosis attributed to infection with an unclassified protozoan. Thirteen woodchucks had primary hepatocellular carcinoma. Metastasis to the lung was observed in only one woodchuck. These results were compared to liver lesions in 149 woodchuck hepatitis virus-negative woodchucks. Chronic hepatitis comparable to that associated with woodchuck hepatitis virus infection was not observed in woodchuck hepatitis virus-negative woodchucks although in one, a single, small hepatocellular adenoma was found.

Animals↗
PubMed1985

Laboratory assessment of hepatic injury in the woodchuck (Marmota monax).

Normal reference values for total serum protein, albumin, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), gamma glutamyl transferase (GGT), alkaline phosphatase (AP), and total bilirubin were established in 48 clinically healthy woodchucks. To validate the use of these biochemical tests in the woodchuck for assessment of liver injury, carbon tetrachloride was administered to produce hepatocellular necrosis and the common bile duct was surgically occluded to produce cholestasis. Biochemical tests were performed prior to experimental treatment and thereafter in surviving woodchucks for a period of 6 weeks. There were marked increases in the serum activities of AST, ALT, and SDH following carbon tetrachloride administration and all 3 enzymes appeared to be useful markers of acute hepatocellular injury. The predominate biochemical abnormalities in woodchucks with bile duct obstruction were hyperbilirubinemia, hypercholesterolemia and increased serum AP and GGT activities. The increase of GGT occurred earlier following bile duct obstruction and the magnitude of increase was greater than that of AP, suggesting that GGT would be the preferred serum enzyme test in the woodchuck for assessment of cholestatic liver injury.

Alanine Transaminase↗
PubMed1985

Cutaneous histiocytoma in a goat.

A cutaneous histiocytoma involving the scrotum was diagnosed in a 14-month-old French Alpine buck. A wedge biopsy was taken for histologic examination. The remaining tumor regressed spontaneously and had completely resolved within six months of initial observation.

Animals↗
PubMed1984

Granulomatous colitis associated with small strongyle larvae in a horse.

Horses presented with chronic weight loss are difficult to manage clinically. A diagnosis of granulomatous colitis due to mucosal stages of cyathostomes (small strongyles) should be considered in those cases exhibiting weight loss, intermittent diarrhea, hypoalbuminemia, increased serum globulins, and low fecal egg counts. Treatment can be attempted with larva-cidal doses of fenbendazole or ivermectin. Clinical and necropsy findings in one such case are presented.

Animals↗
PubMed1982

Myocardial necrosis secondary to neural lesions in domestic animals.

Focal myocardial necrosis secondary to neural lesions was diagnosed in 2 dogs and 1 horse. In each case, the neural lesions were traumatic in origin. Spinal cord injury was evident in 1 dog; brain damage was evident in the other dog and presumably in the horse. Retrospective analysis of necropsy material showed that many species were affected, without apparent age or sex predisposition. Central nervous system injury resulting from trauma, infection or space-occupying lesions was associated with acute myocardial necrosis in all cases. The myocardial necrosis was rarely fatal; however, it did cause cardiac arrhythmias.

Animals↗
PubMed1982

Parasitic encephalitis due to Baylisascaris sp. in wild and captive woodchucks (Marmota monax).

Twelve of 102 woodchucks submitted for necropsy to the New York State College of Veterinary Medicine had clinical histories of central nervous system disorder. All had multifocal eosinophilic encephalitis with formation of granulomas. Nematode larvae, identified as Baylisascaris sp. were found in six of the 12 and were assumed to be the etiologic agent in all affected woodchucks. Both wild and captive (wild-trapped) woodchucks were affected, and all occurrences were between mid-June and early September.

Animals↗
PubMed1981

The prophylaxis of rat and mouse mammary gland tumorigenesis by suppression of prolactin secretion: a reappraisal.

The purpose of this study was to evaluate the effect of early and temporal CB-154 induced suppression of prolactin secretion on the genesis of mammary tumors in female Sprague-Dawley rats treated i.g. with 3 doses of 7,12-dimethylbenzanthracene (DMBA); doses which yield a high (20 mg), moderate (5 mg) and low (1.25 mg) mammary carcinoma incidence. In addition, the effect of prolactin suppression on the genesis of mammary tumors in strains of rodents which, when treated with maximally tolerated doses of DMBA, develop a moderate (female Lewis rats) and a low (female Long-Evans rats and female Balb/c mice) mammary carcinoma incidence was also evaluated. Daily suppression of prolactin secretion during DMBA treatment (30 days before, during and 30 days after) (series 1) or commencing 30 days after DMBA treatment (for 60-81 days) (series 2) significantly (P less than 0.05) reduced the number of mammary carcinomas in Sprague-Dawley rats treated with 20 and 5 mg DMBA and in Lewis rats (series 2); treatment with CB-154 did not significantly lower mammary carcinoma incidence in Sprague-Dawley rats treated with 1.25 mg DMBA, nor in Lewis rats (series 1), Long-Evans rats and Balb/c mice. These results provide evidence that the effectiveness of prolactin suppression in the prophylaxis of chemical carcinogenesis of the rodent mammary gland is enhanced when a moderate or large dose of the carcinogen is used, or a strain of rodent is used which is moderately or highly susceptible to the mammary oncogenic effects of the carcinogen. Low doses of the carcinogen or use of a rodent strain relatively resistant to the carcinogen nullifies the chemopreventive activities of early prolactin suppression.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Renal excretion of cimetidine.

The renal excretion and certain pharmacokinetic properties of cimetidine were studied in anesthetized rats undergoing moderate osmotic diuresis. When cimetidine concentrations in plasma (Pcim) were low, ca. 2 micrograms/ml, the clearance of cimetidine (Ccim) was 2.64-fold greater than the glomerular filtration rate (GFR). Ccim was lower at higher concentrations, e.g., at ca. 200 micrograms/ml, Ccim/GFR was 1.24. When animals with low Pcim were alkalotic (bicarbonate infusion), Ccim/GFR was 1.82 (different from control, P less than 0.01). In nonalkalotic animals, Ccim/GFR was not influenced by changes in urine flow rate. High levels of Pcim completely blocked net secretion of the cation, tetraethylammonium ion, but did not inhibit the secretion of the anion p-aminohippurate. The half-time of cimetidine in plasma was 43 to 49 min. The apparent volume of distribution was 3.6-fold greater than estimated total body water. We conclude that cimetidine is secreted by the renal organic cation transport mechanism and that it probably undergoes passive reabsorption (nonionic diffusion) to a modest extent when the urine is alkaline. The relatively long half-life of the drug in the body, despite its very high renal clearance, is attributable to the large volume of distribution.

Animals↗
PubMed1980

A micropuncture study of urate excretion by Cebus monkeys employing high performance liquid chromatography with amperometric detection of urate.

Net renal reabsorption of endogenous urate was studied by the micropuncture technique in Cebus monkeys in the absence of osmotic diuresis. Most of filtered urate (more than 70%) was reabsorbed in the proximal convoluted tubules. Samples from early distal tubules contained 9% of filtered urate; approximately 18% being reabsorbed between the late proximal and early distal segments. There was no detectable reabsorption along the distal tubule. Fractional delivery of urate to late distal tubules was greater than fractional excretion, implying reabsorption of some 4% of filtered urate in the collecting system. However, we cannot exclude nephron heterogeneity as the cause of the difference. The foregoing results were obtained using the method of Pachla and Kissinger for the determination of urate. Urate is separated by high performance liquid chromatography and detected by an amperometric technique. We found the method to be sufficiently sensitive, precise and specific for renal micropuncture samples.

Animals↗
PubMed1980

Reaginic hypersensitivity in Otodectes cynotis infestation of cats and mode of mite feeding.

Otodectes cynotis infestations were induced in barrier-reared mite-free cats. By monitoring the infested cats, sequence of humoral and cellular immune reactions to the mites was determined. Delayed hypersensitivity was not demonstrated in vivo, using intradermal skin tests. Reaginic (immunoglobulin E) antibodies, as detected by 72-hour passive cutaneous anaphylaxic reactions, were the earliest form of immune expression. Precipitating antibodies developed later in the course of the experimental infestation. Hematologic indices, including eosinophil counts, were not affected by established infestations. Antibodies prepared against feline whole blood, lymph, epithelium, and RBC indicated that these regularly occurred in extracts prepared from whole mites. It was concluded, therefore, that the feeding mode of mites required that they ingest feline tissue fluids. This mode is the interface by which the host becomes exposed to, and immunized against, mite antigens.

Animals↗
PubMed1979

Laboratory diagnosis in a case of fatal progressive vaccinia due to manifest immunologic deficiencies.

A case of progressive vaccinia is described, in a 21 years old man, diagnosed after 8 months of vaccinial lesion's evolution. The area of vaccination developed progressive necrosis and metastatic lesions evolved on various regions of the body. The vaccinia virus was isolated on the chorioallantoic membrane of embryonated eggs, from the cutaneous lesions, blood, internal organs and even from the apparently intact skin.--The serological tests indicated hypogammaglobulinemia with absence of neutralizing antibodies.--The death occured after 366 days. The progressive vaccinia described above represents the case with the most prolonged evolution known until now.

Adult↗
PubMed1978

Literacy skills of long-term hospitalized mental patients.

The authors tested 48 patients who had lived in a state psychiatric hospital for extended periods to determine their literacy levels. Measures used were the reading test portion of the Adult Basic Learning Examination (ABLE) and selected questions from the Adult Performance Level (APL) test, which attempts to assess competencies necessary to function effectively in society. Nearly half of the patients scored at the fourth-grade level or below on the ABLE, and their scores on the APL were well below norms for other groups. No correlation was found between number of years of hospitalization and test performance. From the findings the authors conclude that both in-hospital and aftercare programs must recognize that literacy level is an important factor in the the rehabilitation or recidivism of patients.

Adolescent↗
PubMed1978

Salicylate excretion in the rat; free flow micropuncture experiments.

As in other animals, the renal clearance of salicylate in the rat is greater when the urine is alkaline than when it is acid. In none of the present experiments was the rate of salicylate excretion greater than the rate of its glomerular filtration. Nevertheless, net secretion of salicylate was observed in the proximal tubules of alkalotic, nonalkalotic diuretic, and normal hydropenic animals when the plasma concentration of salicylate was below 150 microgram/ml. Alkalosis enhanced the salicylate content of proximal tubular fluid (approximately 30%). The enhancement is less than would be expected from published reports of proximal tubular fluid pH, if non-ionized salicylate were the only permeant form of the drug. In the absence of alkalosis and at high plasma concentrations, net reabsorption in the proximal tubule was observed. In some circumstances there is net reabsorption of salicylate between the end of the accessible portion of the proximal tubule and the beginning of the distal. Salicylate is reabsorbed from the distal tubule. There was only a small difference in distal reabsorptive rate between normal and alkalotic animals.

Animals↗
PubMed1977

Effect of mutant host RNA polymerase on the bifunctional activities of P22 gene c1.

The product of phage P22 gene c1 has two functions: (1) it promotes synthesis of repressor and (2) during the first minutes of infection it retards expression of some lytic genes. We call the second, negative function "c1 retardation". We investigated c1 retardation in a mutant host of Salmonella typhimurium that is resistant to rifampicin and carries an altered RNA polymerase. No c1 retardation of DNA synthesis was detectable in this host after infection with wild-type phages. This elimination of the normally detectable c1 function leads to the conclusion that the mutant RNA polymerase interferes with the expression of c1 gene activity. Wild-type genes form clear plaques on the mutant host. Mutants of P22 called cly were isolated by others. These mutants form turbid plaques on the altered RNA polymerase host. Infections with P22 cly in the mutant host resulted in detectable c1 retardation. The cly mutation therefore restores c1 activity in a host which wild-type c1 is not expressed. Two spontaneous mutants were isolated from the mutant host. These two strains allowed partial expression of c1 retardation, although they remained rifampicin resistant. We interpret our data to indicate that expression of the normal functions of the gene c1 product requires an interaction of that product with the host RNA polymerase.

DNA-Directed RNA Polymerases↗