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Biomedical subjects

C H Frith

Publications and source records attributed to C H Frith.

At least 19 recordsLinked to original sources
PubMed1992

Spontaneous neoplasms in B6C3F1 mice.

Spontaneous neoplasms in untreated B6C3F1 mice (200 males and 200 females) used as controls in 4 carcinogenicity studies were evaluated and tabulated. The most common neoplasms in male mice were hepatocellular adenomas/carcinomas (24.5%) followed by alveolar-bronchiolar adenomas/carcinomas (10.0%), lymphoreticular neoplasms (7.0%) [malignant lymphomas mixed (4.5%), histiocytic sarcomas (3.5%)], harderian gland adenoma (6.5%), and hemangiomas/hemangiosarcomas (5.5%). In the females, the most frequently occurring neoplasms were lymphoreticular neoplasms (22.0%) [malignant lymphoma mixed (10.0%), malignant lymphoma lymphocytic (6.5%), histiocytic sarcomas (5.5%)] followed by pituitary adenomas (15.5%), alveolar-bronchial adenomas/carcinomas (11.5%), hepatocellular adenomas/carcinomas (7.0%), harderian gland adenomas, uterine stromal polyps (2.5%), and hemangiomas/hemangiosarcoma (2.0%). The incidence of tumors in various other organs was found to be low.

Animals↗
PubMed1992

Spontaneous neoplasms in aged CD-1 mice.

Spontaneous neoplasms in untreated control CD-1 mice (725 males and 725 females) used in carcinogenicity studies were evaluated and tabulated. The most common neoplasms in male mice were alveolar-bronchiolar adenomas (19.3%) followed by hepatocellular adenomas (11.0%), lymphoreticular neoplasms (6.8%), hepatocellular carcinomas (5.7%), Harderian gland adenomas (2.9%), alveolar-bronchiolar carcinomas (2.5%), and testicular interstitial cell tumors (1.9%). In the females, the most frequently occurring neoplasms were lymphoreticular neoplasms (16.4%) followed by alveolar-bronchiolar adenomas (12.3%), uterine endometrial polyps (4.3%), uterine leiomyomas (3.5%), mammary adenocarcinomas (2.5%), hepatocellular adenomas (1.8%), hemangiomas (1.7%), Harderian adenomas (1.7%), alveolar-bronchiolar carcinomas (1.5%), and pituitary adenomas (1.1%). Tumors in other various organs were found at a low incidence.

Aging↗
PubMed1992

Histiocytic sarcoma in an aging gerbil.

A histiocytic sarcoma in an aging female gerbil is described. The neoplasm primarily involved the spleen and liver, and these organs were considered the primary sites of neoplastic origin. No neoplastic infiltration was noted in the uterus or ovaries as is commonly seen in the female mouse. This is the first report of histiocytic sarcoma in gerbils.

Animals↗
PubMed1991

Incidence, distribution, and morphology of amyloidosis in Charles Rivers CD-1 mice.

The incidence, morphology, and distribution of amyloidosis were reviewed in a 2-year toxicity-oncogenicity study in Charles Rivers CD-1 mice. Amyloid was present in the duodenum, jejunum, mesenteric lymph node, and ovary in animals sacrificed at 8 months. In animals sacrificed at 12 months, amyloid was also present in the adrenal gland, gall bladder, heart, ileum, kidney, pancreas, parathyroid, spleen, glandular stomach, testis, and thyroid. In the animals sacrificed at 24 months, the gland was also involved. The organs most frequently involved at 24 months included the adrenal gland, duodenum, jejunum, ileum, heart, kidney, liver, mesenteric lymph node, ovary, spleen, and thyroid.

Adrenal Glands↗
PubMed1991

Spontaneously occurring leiomyosarcomas of the mouse urinary bladder.

Spontaneous leiomyosarcomas of the mouse urinary bladder have not been reported. Data from 8 chronic toxicity/oncogenicity studies that included 400 male and 400 female mice were reviewed and evaluated to gather information on spontaneously occurring urinary bladder leiomyosarcomas. Three control mice from 3 different studies had leiomyosarcomas in the submucosa of the trigone area of the urinary bladder. These tumors were not connected to the surface epithelium; however, they were connected to and destroyed the smooth muscle layer of the urinary bladder. This communication describes the incidence and histopathological features of these neoplasms.

Animals↗
PubMed1990

Spontaneous primary astrocytoma in the spinal cord of a mouse and a rat.

A spontaneous astrocytoma was observed as an incidental finding in the thoracic spinal cord of a control Charles Rivers CD-1 female mouse from a 2 yr oncogenicity study. An astrocytoma was also observed in the lumbar spinal cord of a Charles Rivers Sprague-Dawley control, female rat from a 2 yr oncogenicity study. The mouse was clinically normal and was sacrificed at the end of the 2 yr study. The rat was killed at 512 days of age because of posterior paralysis.

Animals↗
PubMed1988

Neurochemical and neurohistological alterations in the rat and monkey produced by orally administered methylenedioxymethamphetamine (MDMA).

MDMA is an amphetamine analog prescribed by some health professionals in the field of psychotherapy and used as a recreational drug by the general public. In recent reports, investigators have suggested that MDMA produces acute neurotoxicity when administered by subcutaneous injection. In order to determine if MDMA produces lasting neurochemical alterations after oral administration, groups of six rats (adult male Sprague-Dawley) were dosed by gavage with either 40 or 80 mg/kg of MDMA or saline vehicle once every 12 hr for 4 days. These rats were terminated 2 weeks after the first dose along with an additional group of rats (80 mg/kg) terminated 4 weeks after the first dose. Brain regions including the hippocampus (H), caudate nucleus (CN), hypothalamus (HY), frontal cortex (FC), and brain stem (BS) were analyzed by HPLC with electrochemical detection for concentrations of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and norepinephrine (NE). In the CN, 40 mg/kg MDMA produced no change in DA, DOPAC, or HVA, but a 50-60% decrease in 5-HT and 5-HIAA concentrations was observed at 2 weeks. Similar effects were observed at 80 mg/kg at both 2 weeks and 4 weeks. A temporary decrease was also seen in DA (21%) and in HVA (34%) 2 weeks but not 4 weeks after the 80 mg/kg dose regimen. In the H, MDMA (40 or 80 mg/kg) produced no change in NE, but a 50-60% decrease was seen in 5-HT and 5-HIAA concentrations at 2 weeks. Concentrations of 5-HT and 5-HIAA were significantly decreased in the HY and FC by all MDMA treatments, but DA and DOPAC concentrations were not altered as compared to vehicle controls. BS was least affected by treatment with no change in DA, DOPAC, or 5-HIAA concentrations and only a slight decrease in 5-HT (19-33%) concentrations at 2 weeks but not at 4 weeks. To determine the sensitivity of the nonhuman primate to MDMA, a total of nine rhesus monkeys were dosed with vehicle or 5 or 10 mg/kg MDMA (n = 3) by gastric intubation twice per day for 4 days. One month after MDMA dosing, a dose-related reduction from vehicle control values for 5-HT and 5-HIAA was observed. These results indicate that the monkey may be more sensitive than the rat to the persistent serotonergic neurotoxicity of MDMA.(ABSTRACT TRUNCATED AT 400 WORDS)

3,4-Methylenedioxyamphetamine↗
PubMed1987

Tumorigenic responses to lindane in mice: potentiation by a dominant mutation.

Obese mottled yellow Avy/a, lean pseudoagouti Avy/a and lean black a/a (YS X VY) F-1 hybrid female mice were fed diet containing 160 p.p.m. lindane (gamma-hexachlorocyclohexane) for 6, 12, 18 or 24 months. Clara cell hyperplasia was present in a majority of the mice after six months of lindane ingestion; however, more yellow mice (77%) than pseudoagouti (50%) or black (56%) mice had developed this lesion. Continued ingestion of lindane increased the incidence of Clara cell hyperplasia and resulted in similar prevalences in the three phenotypes. Lung tumors associated with lindane ingestion for 24 months were found only in yellow (19%) and pseudoagouti (14%) mice but not in the black mice. Prevalences of hepatocellular adenomas and carcinomas were very low (less than 10%) in untreated pseudoagouti and black mice. Lindane ingestion for 24 months resulted in an hepatocellular adenoma prevalence of 12% in pseudoagouti mice and 3% in black mice; comparable hepatocellular carcinoma prevalences were 5% and 1%. Among yellow mice fed lindane diet for 24 months, adenoma prevalence was 35% (9% among untreated controls) but carcinoma prevalence was only 17% (13% among controls). The tumorigenic responses evoked by lindane feeding in the lean pseudoagouti Avy/a mice but not in the black a/a mice indicate, for the first time, that the Avy gene itself, in the absence of obesity, sensitizes cells to transformation. The greater prevalence of hepatocellular adenomas in obese yellow Avy/a than in lean pseudoagouti Avy/a mice implicates obesity-associated factors in tumor promotion. Similarly, the increased prevalence of hepatocellular carcinomas in untreated obese yellow Avy/a mice, as compared to lean pseudoagouti mice, implicates obesity-associated factor as favoring histiotypic progression of liver tumors. Thus, the Avy gene not only sensitizes cells to respond to tumorigenic stimuli but also, by the induction of obesity, enhances promotion and progression of transformed cells.

Adenoma↗
PubMed1986

Contributions of recent research to the classification of spontaneous lymphoid cell neoplasms in mice.

The present review focuses on the mouse as an experimental immunopathologic model for non-Hodgkins' lymphomas and related leukemias. Immunomorphologic evidence will be presented which demonstrates that B and T cell subtypes of mouse lymphoid cell neoplasms resemble and are analogous to B and T cell subtypes of human lymphoid cell neoplasms. The many experimental advantages of the mouse system will be stressed with a particular emphasis on the concept that this newly defined immunomorphologic approach should be effectively combined with biologic, molecular, and cytogenetic parameters.

Animals↗
PubMed1979

Morphologic classification of inflammatory, nonspecific, and proliferative lesions of the urinary bladder of mice.

A morphologic classification of inflammatory, nonspecific, and proliferative lesions of the urinary bladder of mice has been developed. The system was developed over a period of several years in order to tabulate and summarize the lesions for review. The classification has successfully met the needs of the National Center for Toxicological Research and has also provided useful information in understanding the biologic significance of urothelial lesions in mice.

Animals↗
PubMed1977

Computer-assisted collection and analysis of pathology data.

At the National Center for Toxicological Research, long-term experiments with mice requiring the collection, storage, retieval, and analysis of an inordinate amount of data necessitated the development of an automated pathology information system. The system included automatic collection of mouse body and organ weights and hematologic findings; the use of mark-sensitive forms for the collection of gross and microscopic findings; and the use of computers for the storage, retrieval, and analysis of pathology data.

Animals↗
PubMed1976

Hepatic cytologic and neoplastic changes in mice given benzidine dihydrochloride.

The administration of benzidine dihydrochloride in water to mice for up to 39 weeks resulted in hemosiderosis of the spleen, focal vacuolization of the transitional epithelium of the urinary bladder, and chronic inflammation and cytologic and neoplastic changes in the liver. Basophilic and acidophilic cytologic foci appeared in the liver as two distinct entities and both appeared preneoplastic. Benign and malignant liver tumors were also seen. Both types of cytologic changes and malignant liver tumors were more common in the female than male mouse.

Aminobiphenyl Compounds↗
PubMed1976

Advances in automation for experimental pathology.

The establishment of the National Center for Toxicological Research (NCTR), Jefferson, AR, to study long term effects of low doses of potentially toxic substances, including carcinogens, resulted in the initiation of chronic experiments requiring histophatologic studies of large numbers of animals. Processing the tissues and recording and analyzing the massive amount of pathologic data from these studies required innovative automated technics. The result was a unique computerized pathology data system of NCTR. The system encompasses the development of training programs for necropsy techincians, histology technicians, and pathology tissue screeners; the use of automated equipment for processing, embedding, sectioning, and staining tissue; the use of prelabeled cassettes, slides, and pathology forms; the use of mark-sensitive forms for the collection of gross and microscopic findings; the use of data collection terminals for animal identification, animal weights, and organ weights; the collection of gross and microscopic data on a Mod Comp III minicomputer; and the storage, analysis, and generation of pathology reports and tables over a data link from an IBM 370-158 computer. Some of the features of this system may be applicable in other toxicology laboratories and medical pathology departments.

Animals↗
PubMed1976

Mast cell neoplasia in mice.

Gross and histopathologic findings were reported for mast cell neoplasia in 2 female BALB/cStCrIBR mice. Microscopic findings included neoplastic mast cells in the liver, spleen, kidney and lymph nodes. Neoplastic mast cells were present in the blood smear of one of the animals.

Animals↗