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Biomedical subjects

J C Gordon

Publications and source records attributed to J C Gordon.

At least 37 records · Page 2Linked to original sources
PubMed1988

Zinc effects on nickel dermatitis in the guinea pig.

Prevention of NiSO4 induced allergic contact dermatitis (ACD) using ZnSO4 in drinking water was studied in a guinea pig model. Without ZnSO4 interventions, nickel (Ni)-exposure resulted in significantly higher (p less than 0.05) stimulation indices (SIs) as compared to non-exposed controls, using NiSO4 as an allergen in the lymphocyte transformation test (LTT). Oral intake of ZnSO4 at both 250 micrograms/ml double-distilled deionized water (DDD) and 500 micrograms/ml DDD resulted in lower SIs than those of control guinea pigs drinking only DDD; the 250 micrograms/ml group had significantly lower SIs (p = 0.025) than controls. There was no significant correlation between intradermal test responses and the SI values of individual guinea pigs exposed to NiSO4. Mean zinc (Zn) concentrations in skin and in whole blood were not statistically different between the NiSO4 exposed control and Zn supplemented groups, nor between Ni-sensitive and non-sensitive animals within groups. The rôle of Zn homeostasis, rôle of the Langerhans cell, effect of Zn supplementation on Ni ACD in other species, and possible blocking effects of other metals should be investigated in future studies.

Administration, Oral↗
PubMed1987

Enzyme-linked immunosorbent assay for Potomac horse fever disease.

An enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) and IgM in natural and experimental infections of equids with Ehrlichia risticii was developed. Ehrlichial organisms purified from an infected mouse macrophage cell line were used as the antigen. IgM was separated from serum IgG by the expedient of spun-column chromatography, allowing the use of an indirect ELISA for quantitation of both IgG and IgM in the test sera. Among 16 paired sera from horses exhibiting clinical signs of Potomac horse fever, 8 were positive by the indirect fluorescent-antibody test (IFA), 11 were positive by the IgG ELISA, and 8 were positive by the IgM ELISA. All IFA-positive specimens were positive by the IgG ELISA, which appeared to be more sensitive than the IFA. In all cases, the IgG ELISA alone would have sufficed for diagnosis when acute- and convalescent-phase sera were available. When 26 single acute- or convalescent-phase serum samples were tested, the IFA detected 8, the IgG ELISA detected 10, and the IgM ELISA detected 6 positive serum specimens. The kinetics of IgG and IgM responses as determined by ELISA in two experimentally infected ponies which survived infection and challenges revealed that specific IgM was short-lived, falling to undetectable levels by day 60 postinoculation, whereas specific IgG persisted for more than 1 year. IgM and IgG were detected as early as days 1 and 10, respectively, postinoculation. The results suggest that the ELISA is more sensitive than the IFA and that the IgM ELISA may provide a means for early diagnosis of Potomac horse fever at or before the onset of clinical signs.

Animals↗
PubMed1986

Comparison of antibodies to Leptospira in white-tailed deer (Odocoileus virginianus) and cattle in Ohio.

A survey was conducted to determine the prevalence of leptospiral antibodies in sera from 248 white-tailed deer (Odocoileus virginianus) in Ohio. The sera were collected at check stations during the hunting season in 1983. The microscopic agglutination microtiter test was used to determine the presence of antibodies to Leptospira interrogans serovars pomona, icterohemorrhagiae, canicola, hardjo, and grippotyphosa. Eighteen of 248 (7.3%) serum samples had antibody titers (greater than or equal to 1:100) to at least one of the five serovars tested, with three of these samples reacting to more than one serovar. Prevalence did not differ significantly between sex or age groups. The serovar antigens reacting most frequently with serum antibodies were grippotyphosa (10 of 22, 45.5%) and pomona (eight of 22, 36.4%). Sera agglutinating with pomona antigen had higher titers (ranging from 1:200 to 1:6,400) than did sera agglutinating with the other serovars. These results were compared to results obtained from cattle tested at the Ohio Department of Agriculture Laboratories during 1983. There was a significant relationship between pomona infections detected in deer and cattle (P less than 0.05), but not with grippotyphosa.

Animals↗
PubMed1986

Canine parvovirus: environmental effects on infectivity.

Effects of various environments on the infectivity of canine parvovirus-2 (CPV-2) were studied. When CPV-2 was subjected to several controlled indoor environments, the virus remained infective at approximate initial inoculation amount (median tissue culture infective dose [TCID50] = 10(5.5)/ml) for 12 months at temperatures less than -20 C, decreased to TCID50 of 10(2.3)/ml by 12 months at 4 C, and had a TCID50 of less than 10(1)/ml at room temperature (20 C) or higher in less than 2 months. The CPV-2 subjected to outdoor environments was not infective beyond 5 months, except that kept in areas protected from sunlight and drying conditions. The virus surviving in the outdoor environments was not infective for study dogs, whereas the virus maintained at less than 20 C was.

Animals↗
PubMed1986

Evidence of paratuberculosis in Ohio's white-tailed deer, as determined by an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed and used to detect antibodies to Mycobacterium paratuberculosis in serum samples obtained in December of 1983 from 954 hunter-killed white-tailed deer (Odocoileus virginianus) in 13 Ohio counties. Positive or negative status was determined by calculating a signal-to-noise ratio, a ratio between the optical density of the test serum and negative reference sera; a ratio of greater than or equal to 3.0 was considered positive. Twenty-four samples (2.5%) were found to be assay positive, using this method. A statistically significant difference among age groups was found, with those less than or equal to 6 months of age having a lower proportion of positives. Differences by sex were not observed. To determine the validity of the ELISA in deer, serum samples from 46 fallow (Dama dama) and axis deer (Axis axis) harvested from a known infected population were tested by ELISA and agar-gel immunodiffusion. The agar-gel immunodiffusion test showed evidence of exposure of the deer to M paratuberculosis or a related antigen. The ELISA closely approximated the prevalence of paratuberculosis infection as previously determined by fecal culture in this population. As a result of these tests, it was concluded that free-ranging Ohio deer have been infected with M paratuberculosis or exposed to a closely related antigen.

Animals↗
PubMed1985

Canine brucellosis in a household.

Three cases of canine brucellosis from the same household were discovered during a serosurvey of privately owned dogs. One dog was found to be seropositive and culture-positive, 1 dog was seropositive, and 1 dog had suspect test results, with eye lesions suggestive of Brucella canis infection. All dogs had signs seen with B canis infection, but none was pathognomonic. Although pathologic findings in 2 of the dogs were consistent with findings reported by other investigators, none was conclusive for brucellosis. The 2-mercaptoethanol tube agglutination test was utilized as the diagnostic test.

Agglutination Tests↗
PubMed1985

Rapid enzyme-linked immunosorbent assay for detecting antibodies to canine parvovirus.

A rapid screening assay for determining antibodies to canine parvovirus in dog serum using monoclonal antibodies and enzyme-linked immunosorbent assay (ELISA) technology was developed. The ELISA could be read visually, and the results correlated well with serum neutralization (SN) and hemagglutination inhibition (HI) titers. Sera with SN less than or equal to 1:4 or HI less than or equal to 1:10 had an 87.9% correlation with ELISA and sera with SN greater than or equal to 1:64 or HI greater than or equal to 1:80 had a 94.4% correlation. The assay took only 10 to 15 minutes to perform and did not require specialized equipment. The ELISA should be useful in monitoring dogs for the presence of maternal antibodies against parvovirus and for determining seroconversion after vaccination.

Animals↗
PubMed1984

Partial purification of a water-soluble liver protein that regulates adenylate cyclase activity (basal, hormone- and cholera-toxin-activated) and cholera-toxin-catalyzed ADP-ribosylation of the membrane G protein.

We have found in water-soluble extracts of rat liver (and RL-PR-C cloned rat hepatocytes), prepared in the absence of detergent, a factor that markedly enhances basal, isoproterenol and cholera toxin activation of adenylate cyclase of rigorously washed hepatocyte membranes, in the absence of added GTP. The factor, which has characteristics of a protein with an Mr of approx. 35000, has been fractionated from crude cytosol by gel filtration, and then further purified over 50-fold by sequential ion-exchange chromatography. The site of action of the protein appears to be at the level of the guanine nucleotide regulatory (G) protein of the plasma membrane adenylate cyclase complex, as the factor, cooperatively with GTP, also permitted cholera toxin to ADP-ribosylate (from 32P-labeled NAD) two integral membrane proteins that migrated on SDS-polyacrylamide gel electrophoresis gels with the mobilities (Mr approx. 46 000 and 48 000) generally observed for the guanine nucleotide regulator protein subunits. In this system, isoproterenol did not stimulate ADP-ribosylation, in either the presence or absence of the liver protein factor.

Adenosine Diphosphate Ribose↗
PubMed1984

Epidemiology of Rocky Mountain spotted fever in Ohio, 1981: serologic evaluation of canines and rickettsial isolation from ticks associated with human case exposure sites.

A survey for the prevalence of Rocky Mountain spotted fever (RMSF) antibodies in dogs associated with confirmed human cases in Ohio was conducted during 1981. Twelve of 14 confirmed cases (85%) had a history of dog association prior to onset of RMSF. A total of 29 dogs were included in the study, with 16 dogs providing serum samples for antibody testing and the remainder providing tick samples. Serum samples tested by indirect microimmunofluorescence techniques revealed 12/16 dogs (75%) to be seropositive for Rickettsia rickettsii. A total of 310 ticks were collected from study dogs and the vegetation surrounding RMSF case exposure sites. Twenty-two (7.1%) of these ticks (all Dermacentor variabilis) were found to be infected with spotted fever group rickettsiae. Four ticks (1.3%) were infected with R. rickettsii, 13 (4.2%) with Rickettsia montana, and four (1.3%) with Rickettsia bellii. R. montana, a nonpathogen, was the only rickettsia found in dogs (antibodies) and ticks (isolation) associated with human cases in Southern Ohio.

Animals↗
PubMed1983

Rocky Mountain spotted fever in an urban canine population.

A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. For comparison, 137 blood samples from dogs at the Franklin County Dog Pound also were tested. One dog (0.7%) from the comparison group was seropositive to R rickettsii, with a 1:64 titer. The results indicated a nidus of this disease within the city of Columbus, Ohio.

Animals↗
PubMed1982

Clonal interaction in tumours.

The development of cancer is contingent on the emergence of at least one clone of transformed cells. One method used to investigate whether human tumours are monoclonal depends on the mosaicism in the normal tissues of women heterozygous for the two forms of the enzyme glucose-6-phosphate dehydrogenase (G-6-PD). This mosaicism results from the inactivation of one X chromosome in all somatic cells and should not exist in a monoclonal population. Following the discovery in feral mice of an electrophoretic variant (A) of the X-coded enzyme phosphoglycerate kinase (PGK-1) which differs from the form (B) found in common laboratory mouse strains it was reported that fibrosarcomas induced chemically in hybrids of feral and laboratory-bred mice expressed both enzyme phenotypes, but the conclusion that both were expressed by neoplastic cells was based solely on morphological evidence. The development of histocompatible substrains of mice homozygous for one or other alloenzyme has made it possible to study the clonal composition of tumours under experimental conditions in which the neoplastic status of subpopulations of cells can be verified by transplantation. The experiments we now report, while confirming that murine fibrosarcomas are often pleoclonal, show that the clonal composition may change markedly during tissue culture and on transplantation to congenic hosts. These changes presumably reflect changes in the growth kinetics of differentiating subpopulations of the tumour. Cloned sublines are less readily transplantable than uncloned tumour cell populations, and some sublines are less readily transplantable than others; this suggests that sublines resistant to a host's attack are selected on transplantation or that some sublines require the cooperation of others to survive. We postulate that changes in clonal composition occur also during tumour development, metastasis and recurrence.

Animals↗
PubMed1982

Field evaluation of a canine parvovirus vaccination program, using feline origin modified live virus vaccine.

Antibody titers measured by hemagglutination inhibition testing were determined in previously vaccinated dogs at the time of booster vaccination and 2 weeks later. All vaccines consisted of modified live panleukopenia virus. The booster injection was administered approximately 6 months after the initial parvovirus vaccination series was given. Fecal and serum specimens were collected immediately before and 2 weeks after administration of the booster vaccine for hemagglutination and hemagglutination inhibition testing, respectively. All dogs were privately owned and were from the Columbus, Ohio, area but were from environments with various exposure potentials to canine parvovirus. Results of hemagglutination (HA) testing on feces were negative in all dogs before and after booster vaccination. Therefore, these vaccinations did not interfere with interpretation of HA testing of feces. Results of serum hemagglutination inhibition (HI) testing indicated that 50% of the dogs had serum titers less than 1:80 prior to vaccination and that, of these dogs, 65.2% still had serum titers less than 1:80 2 weeks after the booster vaccination. Only 10.9% of all dogs had a marked increase in serum HI titer after the booster vaccination, indicating that overall serologic response to vaccination was poor. High HI titers (greater than or equal to 1:640) were associated with exposure to other dogs and cats in the neighborhood or to dogs suspected of having had parvovirus infection.

Animals↗
PubMed1975

Incorporation of C-Photosynthate into Protein during Leaf Development in Young Populus Plants.

Gas exchange and protein metabolism were studied in expanding, mature, and near-senescent leaves of young clonal Populus x euramericana cv. Wisconsin-5 plants. Dark respiration, CO(2) evolution in the light, and CO(2) compensation concentrations were highest in unexpanded leaves but declined markedly as leaves matured and aged. Net photosynthesis was highest in nearly mature leaves. Fresh weight continued to increase after leaf expansion was complete, whereas soluble protein levels declined. Changes in the distribution of photosynthetically incorporated (14)C indicated that a high level of protein synthesis and rapid formation of structural components occurred only in expanding leaves. Protein turnover was slight in expanding leaves but was substantial after leaves were mature. Expanding leaves synthesized predominantly fraction I protein (ribulose diphosphate carboxylase). However, formation of this protein from photosynthate was slight once leaves matured.

Journal Article↗
PubMed1971

Changes in total nitrogen, soluble protein, and peroxidases in the expanding leaf zone of eastern cottonwood.

Nitrogen content and soluble protein and anodal peroxidase banding in acrylamide gel changed with leaf and internode development in the expanding leaf zone of eastern cottonwood (Populus deltoides Bartr.). Nitrogen per unit leaf area was high near the apex and decreased to a constant value at the sixth node below it. Soluble protein banding was qualitatively similar for leaves and internodes in this zone, but anodal peroxidases differed between leaves and internodes. The major leaf peroxidase band was absent from the second leaf below the apex but present in the fourth and sixth leaves; its appearance and intensification seemed to parallel the development of photosynthetic activity. The major internode peroxidase band was present in the apex, second, fourth, and sixth internodes, and intensified during internodal development. It is suggested that these two "isoenzymes" may have different functions in vivo.

Journal Article↗