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Biomedical subjects

J C Harshbarger

Publications and source records attributed to J C Harshbarger.

At least 37 records · Page 2Linked to original sources
PubMed1990

Epizootiology of neoplasms in bony fish of North America.

Over the past 25 years, there have been an increasing number of fish tumor epizootics recognized in discrete geographical areas in North America. This is consistent with an association between tumor development in fish and exposure to waterborne contaminants as a result of increased industrialization. Reports of fish tumor epizootics from the literature, plus acquisitions at the Registry of Tumors in Lower Animals, Smithsonian Institution originate from 41 geographical regions in North America. Epizootics of hemic, neural, connective tissue, and gonial neoplasms seem unrelated to environmental pollution, but epizootics of hepatic and epidermal neoplasms appear to be caused or strongly influenced by environmental pollution. The 14 species with epizootic liver tumors are all bottom feeding fish, and tumor-bearing fish are generally located in areas where chemical contaminants are concentrated. Epidermal neoplasms are also found in fish near polluted areas, but a direct cause-and-effect link with chemical carcinogens is not clear.

Animals↗
PubMed1990

Relationship between liver tumors and age in brown bullhead populations from two Lake Erie tributaries.

We compared liver tumor frequencies, and age and length characteristics of brown bullheads (Ictalurus nebulosus) of greater than 250 mm total length from two Lake Erie tributaries. Bullheads taken from Old Woman Creek (n = 144) had no grossly observable liver tumors, while those collected in the highly industrialized Black River (n = 532) had a 30% frequency of grossly visible liver tumors during 1981-1982. Liver lesions diagnosed histologically in a randomly collected sample (n = 125) of brown bullheads from the Black River included both biliary and hepatic lesions, with cancerous neoplasms occurring in 38.4% of the fish. Black River bullheads of combined ages 4 and 5 had a significantly (p less than or equal to 0.05) greater prevalence of biliary carcinomas (35.5%) than those of ages 2 and 3 combined (18.4%). Biliary carcinoma was significantly more prevalent than hepatocellular carcinoma in age 4 fish (sexes combined) and in males of ages 3 and 4. The prevalence of hepatocellular carcinoma was significantly higher in females than in males. Age distributions of bullheads differed significantly between the two sites, while length distributions were similar. No brown bullheads of ages 6 or 7 were collected in the Black River, while these age groups composed 18% of the catch in Old Woman Creek. Brown bullheads of age 5 were almost six times more numerous in the Old Woman Creek than in Black River collections. These age and length distributions are consistent with the hypothesis that brown bullheads in the Black River were subjected to an age-selective mortality associated with high prevalences of liver carcinoma.

Aging↗
PubMed1984

Pseudoneoplasms in ectothermic animals.

Gross and cytologic similarities between certain non-neoplastic conditions and neoplasms in lower animals including fish, amphibians, and reptiles have invited misinterpretations and contested interpretations. Major categories of pseudo-neoplasms, illustrated by specific examples from material accessioned into the Registry of Tumors in Lower Animals, include infections by foreign organisms which resemble host cells (algal protothecosis and amebic pseudotumors); unusual normal conditions [giant islets of endocrine pancreas (Brockmann bodies) in liver, atypical sites of hematopoietic tissue]; nonparasitic hyperplasia (goiter, ectopic thyroid, erythroblastic proliferation suggestive of pernicious anemia, adenofibrosis); parasite-induced hyperplasia (trematode-induced fibrosis, ciliate-induced monocytic leukocytosis, trematode-induced melanosis, glochidiosis); dysmorphogenesis (teratoid anomalies); virus-induced hypertrophy (lymphocystis); and reactive lesions (metaplasia, regeneration, inflammation).

Adenocarcinoma↗
PubMed1982

Epizootic neoplasms in fishes from a lake polluted by copper mining wastes.

Examination of fishes from Torch Lake, Houghton County, Mich., revealed epizootic neoplasms of several types in two closely related species. Saugers, Stizostedion canadense, and walleyes, Stizostedion vitreum, were commonly affected with hepatocellular carcinomas, dermal ossifying fibromas, and perivisceral masses resembling mesotheliomas that were usually associated with the mesenteric capsule of the spleen. Saugers were 100% affected with liver neoplasms. Histopathologic and ultrastructural aspects of the neoplasms are described. Torch Lake has been used as a repository for copper mining waste to the extent that an estimated 20% of the original volume has been filled in by these materials. Several direct and indirect etiologic roles for the mine waste as causative agents of the fish tumors are discussed.

Animals↗
PubMed1981

Intranuclear inclusion bodies within neurons of spinal and cranial ganglia in three cyprinid species.

A histological examination of 205 fish representing four cyprinid species from a site 2.5 miles north of Wheeling, West Virginia, on the Ohio River revealed large (2--4 micron) cuboidal intranuclear inclusion bodies (NIB's) within neurons in the cranial and spinal ganglia of three species. Because the minnows had been caught during a yearly sampling of fish, an additional 63 minnows were taken the following year. Inclusions were again observed. The NIB's stain strongly with phloxine as well as with Mallory and Giemsa stains, appearing bright red or pink. Various histochemical tests indicated that the inclusions contain protein and lipid but no carbohydrates or nucleic acids. No heavy metals were detected by electron probe analysis. At the ultrastructural level the inclusions exhibit subunits resembling hexagons measuring 326--350 nm. Previously suggested causes for such inclusions include effects of viruses, aging, drugs, cellular transformation, and an altered metabolic state of affected cells.

Animals↗
PubMed1977

Chlamydiae (with phages), mycoplasmas, and richettsiae in Chesapeake Bay bivalves.

Intracytoplasmic chlamydia-like organisms, some with phages, rickettsia-like organisms, and mycoplasma-like organisms have been found in clams and oysters from the Chesapeake Bay area by electron microscopy. None of these organisms have been previously detected in mollusks, nor have phages been previously observed in Chlamydia sp.

Animals↗