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Biomedical subjects

P R Bowser

Publications and source records attributed to P R Bowser.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effect of soybean protein on serological response, non-specific defense mechanisms, growth, and protein utilization in rainbow trout.

Rainbow trout (Oncorhynchus mykiss) were fed chemically and immunologically defined diets containing either a low-temperature fish meal or soybean preparations containing high (SBM) or low levels of the globular antigenic proteins glycinin (G) and beta-conglycinin (BC) for 26 weeks. While trout fed both soybean preparations exhibited poorer growth than those fed fish meal, those fed the soya diet with high levels of G and BC showed the most significant growth diminution, elevated feed conversion and impaired utilization of dietary protein. Changes in intestinal morphology were also observed in fish fed the SBM diet, coinciding with the inferior nutritional performance. Several serologic and non-specific immune defense mechanisms were monitored. Cell counts showed increased leukocyte cell numbers as well as increased concentrations of plasma protein and immunoglobulin in the soya-fed fish. Increased neutrophil, monocyte and macrophage activity, as assessed by several oxidative radical production and phagocytic index assays, were higher in the soya-fed fish, possibly indicating an inflammatory or hypersensitivity response. The results of this study suggest that antigenic soya protein affects non-specific defense mechanisms, growth performance, and protein utilization in rainbow trout. Furthermore, it would appear that dietary sensitivity can be overcome by process removal of this immunologically characterized antigen in soybean protein. Serological and immunological assessments appear to be very useful criteria for evaluating various protein sources for fishes.

Animals↗
PubMed1992

Pharmacokinetics of enrofloxacin in fingerling rainbow trout (Oncorhynchus mykiss).

The pharmacokinetics of intravenously and orally administered enrofloxacin was determined in fingerling rainbow trout (Oncorhynchus mykiss). Doses of 5 or 10 mg enrofloxacin/kg body weight were administered intravenously to 26 fish for each dose and blood was sampled over a 60-h period at 15 degrees C. Two groups of fish were treated orally with 5, 10, or 50 mg/kg (80 fish/dose at each temperature) and held at 15 degrees C or 10 degrees C during the 60-h sampling period. Following intravenous administration, the serum concentration-time data of enrofloxacin in rainbow trout were best described by a two-compartment open model for both doses of 5 and 10 mg enrofloxacin/kg. The hybrid rate constants alpha and beta did not differ between doses. The distributional phase was rapid with a half-life of 6-7 min for both doses. Overall half-lives of elimination were 24.4 h (95% CI = 20.2-30.8) and 30.4 h (24.2-41.0), respectively, for the 5- and 10-mg/kg doses. A large Vd(area) was observed following dosing of either 5 or 10 mg enrofloxacin/kg,: 3.22 and 2.56 l/kg, respectively. Whole body clearance for 5 mg/kg was 92 ml/h.kg and 58 ml/h.kg at the 10-mg/kg dose. Following oral administration, the serum concentration-time data for enrofloxacin were best described as a one-compartment open model with first-order absorption and elimination. Apparent Ka over all doses at 10 degrees C averaged 62% less than apparent Ka at 15 degrees C. Estimates of the apparent t(1/2)e over both temperatures ranged from 29.5 h (18.4-73.4) to 56.3 h (38.3-106.6). Bioavailability averaged 42% over all doses at 15 degrees C and was decreased to an average of 25% at 10 degrees C. Peak serum concentrations appeared between 6 and 8 h following dosing. A dose of 5 mg/kg/day was estimated to provide average steady-state serum concentrations at 10 degrees C that are approximately 4.5 times the highest reported MIC values for Streptococcus spp., the fish pathogen least sensitive to enrofloxacin. Owing to the long apparent half-life of elimination of enrofloxacin in fingerling trout, it would take approximately 5 to 9 days to achieve these predicted steady-state serum concentrations; this estimate is important when considering the duration of therapy in clinical trials.

Absorption↗
PubMed1992

Molecular characterization of a unique retrovirus associated with a fish tumor.

The walleye dermal sarcoma is a mesenchymal tumor which seasonally affects up to 27% of adult walleye fish (Stizostedion vitreum). It arises multicentrically in the dermis, in which its development remains restricted. We report the molecular cloning of a type C retrovirus from this tumor. The genome of this virus (13.2 kb) is larger than that of all retroviruses and in that respect is approximated only by the recently characterized spumaviruses. In tumors, the predominantly unintegrated linear viral DNA has a single-stranded gap region which is similar to the structure found in some lentiviruses and all spumaviruses. The presence of at least four viral transcripts suggests that this virus has the capacity to encode accessory functions and is reminiscent of the transcriptional complexity of lentiviruses and spumaviruses.

Animals↗
PubMed1990

Experimental transmission of a dermal sarcoma in fingerling walleyes (Stizostedion vitreum vitreum).

Dermal sarcoma is a benign skin tumor of adult walleyes (Stizostedion vitreum vitreum) with a suspected viral etiology. A laboratory study was initiated to determine if the tumor could be experimentally transmitted by inoculating young walleyes with materials prepared from tumors from adult fish. Eighty walleye fingerlings were divided into four groups of 20 fish each. Two groups were inoculated intramuscularly at 4 months of age either with live tumor cells or with cell-free filtrates of sonicated tumor cells. The two other groups were used as controls and were inoculated either with cultured cells from normal walleye fry or with tissue culture media. Neoplasms, similar to the dermal sarcoma affecting adult walleyes, were observed after 4 months only in fingerlings inoculated with cell-free filtrates of sonicated tumor cells. Like the tumor affecting wild adult walleyes, the transmitted tumors were restricted to the dermis and originated from the superficial surface of scales. They never invaded locally and never metastasized. The transmitted tumors differed from tumors of adult walleyes in their severity and the absence of osteoid. The multicentric origin of transmitted walleye dermal sarcoma suggests that the virus spreads systemically and that tumor cells are polyclonal. This successful transmission of the lesion, along with the presence of C-type virus particles budding from tumor cells in two of seven tumor-bearing fingerlings, supports a retroviral etiology.

Animals↗
PubMed1990

Histologic and ultrastructural studies of dermal sarcoma of walleye (Pisces: Stizostedion vitreum).

Sixty-seven adult walleye fish were examined by light and transmission electron microscopy. The fish were affected by a mesenchymal tumor previously termed Walleye Dermal Sarcoma that commonly affects up to 27% of the population seasonally. Biopsies from 24 fish were collected, and complete postmortem examinations were performed on 43 fish. Grossly, the tumors had the appearance of randomly distributed, often clustered, spherical nodules, 2-5 mm in diameter with a smooth and often ulcerated surface. The tumors arose from the superficial surface of scales and consisted of fibroblast-like cells separated by a moderate amount of collagen (43/67) or osteoid material (24/67). Lymphocytic infiltration (28/67) associated with vacuolar degeneration of tumor cells (28/67) and centrally located coagulation necrosis (30/67) were observed. Although tumor cells were often highly anaplastic, no local invasions or metastases were present. In contrast with previous descriptions of this tumor, no viral particles could be observed electron microscopically. The variably anaplastic appearance of the tumor, its biological behavior, and its restriction to dermis are features in common with canine cutaneous histiocytoma and equine sarcoid. The multicentric origin, the restriction to the dermis, and the absence of invasion or metastases of Walleye Dermal Sarcoma differ from retrovirus-induced avian and murine sarcomas that arise locally, that invade, and that often metastasize.

Animals↗
PubMed1988

Seasonal prevalence of skin tumors from walleye (Stizostedion vitreum) from Oneida Lake, New York.

A seasonal survey of skin tumor prevalence in walleyes (Stizostedion vitreum) was conducted during the ice-free period on Oneida Lake, New York in 1986. During the survey, 1,028 walleyes were collected and examined for the presence of lymphocystis disease, dermal sarcoma, discrete epidermal hyperplasia and diffuse epidermal hyperplasia. Skin growths were high in prevalence in early spring, low in prevalence during the summer, and again high in prevalence in the fall. Lymphocystis disease and dermal sarcoma were more frequently observed than either discrete or diffuse epidermal hyperplasia. Histologically, a moderate to severe inflammatory response was associated with dermal sarcoma in the early spring and late spring but not in the fall. Regardless of the time of year, varying degrees of inflammatory response were seen associated with lymphocystis disease. Samples were inadequate to assess seasonal trends in incidence of discrete and diffuse epidermal hyperplasia.

Animals↗
PubMed1987

Effect of water temperature on the clinical outcome of infection with Edwardsiella ictaluri in channel catfish.

Channel catfish fingerlings (mean body weight, 19 +/- 3 g each) were given intraperitoneal inoculations of Edwardsiella ictaluri suspensions of 10(4), 10(5), or 10(6) bacteria. Control fish were inoculated intraperitoneally with sterile 0.85% NaCl solution. Ten-day trials were conducted at water temperatures of 17, 21, 23, 25, 28, and 32 C. Differences in mortality between E ictaluri-infected fish and fish used as controls were observed at water temperatures of 23, 25, and 28 C, but not at temperatures of 17, 21, and 32 C. Clinical signs and lesions induced by intraperitoneal inoculation of E ictaluri were comparable with those found with the intestinal form of the natural disease. The characteristic erosion of skin and muscle overlying the skull, known as the "hole-in-the-head" lesion, was not observed. A given fish may be susceptible to infection at any water temperature, but a population is at risk when water temperatures are in the 22 to 28 C range.

Animals↗
PubMed1987

A lymphosarcoma in an Atlantic salmon (Salmo salar).

A lymphosarcoma that appeared to be of thymic origin and of lymphoblastic type was found in a 3.5-yr-old Atlantic salmon (Salmo salar). The fish was from a population of 60 broodfish maintained at a research fish laboratory. A large tumor mass was found under the left operculum. Small tumor nodules were found on the swim bladder and in the abdominal adipose tissue. The location of this neoplasm differed from those of previously described tumors in this fish species.

Animals↗
PubMed1986

Channel catfish virus: use of nucleic acids in studying viral relationships.

Restriction digestion patterns were used to determine differences in the DNA of various isolates of channel catfish virus (CCV). All viruses were different from each other and from the type strain of CCV. The differences in the digestion patterns were used to relate the viruses quantitatively as to sequence divergence between all pairs of viruses. A range of values from 104 nucleotide changes to 1,690 nucleotide changes/total DNA of CCV was found for the various pairs. A cladistic analysis produced a phylogenetic network relating the viruses by possible ancestory. This network indicated that some viruses were relatively more separated from other viruses that were clustered in the network. A phenetic analysis indicated that the viruses that were clustered in the network were also reasonably similar to one another.

Animals↗
PubMed1984

Dietary vitamin E requirement of fingerling channel catfish.

Two experiments were conducted to reevaluate the dietary vitamin E requirement of fingerling channel catfish. Purified diets containing 1% cod liver oil, 4% stripped lard and adequate selenium supplemented with graded levels of DL-alpha-tocopheryl acetate were used in both experiments. The results indicate that the previously reported requirement value, which was based on growth and pathological changes, was underestimated. The minimum dietary vitamin E requirement in the form of DL-alpha-tocopheryl acetate was determined to be 50 mg/kg of diet based on 16-week liver microsomal ascorbic acid-stimulated lipid peroxidation data. No differences were observed in growth rates or feed efficiencies in either experiment. No gross pathologies or hematological changes were evident in fish fed different levels of vitamin E for 20 weeks, except red blood cell hemolysis, which was elevated at the lower levels. Histological lesions were only observed in fish receiving the 0 mg/kg diet. A marked multifocal splenic hemosiderosis was observed in these fish. A mild multi-focal hemosiderosis was observed in the pancreatic tissue surrounding the hepatic vasculature. The pancreatic tissue appeared reduced from that observed in fish fed higher levels of vitamin E. No significant lesions were observed in the other tissues examined.

Animals↗
PubMed1983

Dietary pantothenic acid requirement of fingerling channel catfish.

Two experiments were conducted to reevaluate the dietary pantothenic acid requirement for fingerling channel catfish. Purified diets supplemented with calcium d-pantothenate were used in both experiments. The results indicate that the previously reported requirement value was underestimated. The minimum dietary calcium d-pantothenate level that produced maximum growth, feed efficiency and prevented the characteristic deficiency sign of gill lesions was 15 mg/kg of diet. The gill lesions were detected in 2 weeks in fish fed deficient diets. A reduction in the gill lesions was evident within 2 weeks after fish fed the deficient diet were converted to a diet containing 40 mg calcium d-pantothenate per kilogram of diet. In one experiment there appeared to be a high correlation between disease susceptibility and dietary calcium d-pantothenate level. Based on these observations and since the requirement may vary depending on fish size, age, water temperature, water ionic strength, fish density, oxygen availability, etc., we recommend a value of 30 mg calcium d-pantothenate per kilogram of diet be used in formulating catfish feeds.

Animal Nutritional Physiological Phenomena↗
PubMed1980

Fish cell lines: establishment of a line from ovaries of channel catfish.

A cell line was established from the ovaries of a healthy, juvenile channel catfish, Ictalurus punctatus. These cells, designated CCO, have been passed 130 times during 3 years. The cells grow well in Eagle's MEM-10 at a temperature of 30 degrees C. Species of origin of the cells was confirmed by a cytotoxic dye exclusion test. The cells were found to be free of bacterial and fungal contamination. A study of chromosome preparations indicated that the karyotype is still in a state of flux. The CCO line replicated channel catfish virus but was refractory to 12 other viruses, 4 from fish, 1 from birds, and 7 from mammals.

Animals↗
PubMed1980

Channel catfish virus: comparative replication and sensitivity of cell lines from channel catfish ovary and the brown bullhead.

A cell line derived from channel catfish ovary tissue was compared with the brown bullhead (BB) cell line for their respective abilities to replicate and detect channel catfish virus (CCV). The channel catfish ovary cell line (CCO) produced cytopathic effects (CPE) more rapidly and detected CCV at higher dilutions than did the BB cell line. Production of CCV was more rapid in CCO cells than in BB cells, but the peak titers of the two lines were not significantly different. The CCO cell line was shown to be the more sensitive cell line for CCV research and diagnostics.

Animals↗