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Biomedical subjects

J C Gordon

Publications and source records attributed to J C Gordon.

At least 19 recordsLinked to original sources
PubMed2005

Screening for undiagnosed parkinsonism in people aged 65 years and over in the community.

We screened a random sample of 2449 people aged 65 years and over for undiagnosed parkinsonism, using a postal screening questionnaire followed by clinical neurological assessment. Amongst the 1556 (63.5%) patients who responded, four patients with previously undiagnosed parkinsonism were identified, suggesting a prevalence of 257 per 100,000 (95% CI 70, 658) in this age-group. Although only small, the numbers were sufficient to significantly increase the incidence of parkinsonism in an incidence study. Two simple screening questions achieved a high sensitivity for newly diagnosed parkinsonism of 95%, but a low specificity of 28%.

Aged↗
PubMed2002

Experimental induction of equine protozoan myeloencephalitis (EPM) in the horse: effect of Sarcocystis neurona sporocyst inoculation dose on the development of clinical neurologic disease.

The effect of inoculation dose of Sarcocystis neurona sporocysts on the development of clinical neurologic disease in horses was investigated. Twenty-four seronegative weanling horses were subjected to the natural stress of transport and then randomly assigned to 6 treatment groups of 4 horses each. Horses were then immediately inoculated with either 10(2), 10(3), 10(4), 10(5), or 10(6) S. neurona sporocysts or placebo using nasogastric tube and housed indoors. Weekly neurologic examinations were performed by a blinded observer. Blood was collected weekly for antibody determination by Western blot analysis. Cerebrospinal fluid was collected before inoculation and before euthanasia for S. neurona antibody determination. Horses were killed and necropsied between 4 and 5 wk after inoculation. Differences were detected among dose groups based on seroconversion times, severity of clinical neurologic signs, and presence of microscopic lesions. Seroconversion of challenged horses was observed as early as 14 days postinfection in the 10(6) sporocyst dose group. Mild to moderate clinical signs of neurologic disease were produced in challenged horses from all groups, with the most consistent signs seen in the 10(6) sporocyst dose group. Histologic lesions suggestive of S. neurona infection were detected in 4 of the 20 horses fed sporocysts. Parasites were not detected in equine tissues by light microscopy, immunohistochemistry, or bioassay in gamma-interferon gene knockout mice. Control horses remained seronegative for the duration of the study and had no histologic evidence of protozoal infection.

Animals↗
PubMed2001

The 5-HT3 antagonist tropisetron (ICS 205-930) is a potent and selective alpha7 nicotinic receptor partial agonist.

The 5-HT3 receptor antagonist tropisetron (ICS 205-930) was found to be a potent and selective partial agonist at alpha7 nicotinic receptors. Two other 5-HT3 receptor antagonists, ondansetron and LY-278,584, were found to lack high affinity at the alpha7 nicotinic receptor. Quinuclidine analogues (1 and 2) of tropisetron were also found to be potent and selective partial agonists at alpha7 nicotinic receptors.

Animals↗
PubMed2000

Congenital pseudoarthrosis of the tibia.

Congenital pseudoarthrosis of the tibia remains one of the most difficult conditions to treat in orthopedic surgery. Seven cases were treated in our hospital by different methods. Three out of seven patients were healed, two of these refractured. At follow-up, the success rate was 14% (one out of seven cases). It is our recommendation that early primary amputation with an appropriate prosthesis should be considered, and that the final evaluation should not be based on obtaining bone union, but on the level of function of the lower extremity.

Adolescent↗
PubMed2000

Humoral immune response of dogs immunized with salivary gland, midgut, or repeated infestations with Rhipicephalus sanguineus.

The antibody (Ab) responses of dogs immunized with adult tick salivary gland (TSG), midgut (TMG), or repeated infestations of Rhipicephalus sanguineus were monitored to determine if there is an association between Ab production and R. sanguineus performance. Tick-naïve dogs were immunized with TSG or TMG and subjected to two challenge infestations. The control group was infested five times at 21-day intervals. The ELISA technique was used to measure Ab levels in sera from these dogs, which expressed different forms of resistance against R. sanguineus. In dogs immunized with TSG or TMG, similar Ab levels were detected against TMG, TSG, muscle, synganglion, and reproductive organs. However, these sera had different Ab levels against egg mass, unfed larvae, fed larvae, and nymph antigens. Ab levels to muscle, nerve, and reproductive antigens were lower than those observed when TMG or TSG antigens were used. Sera from dogs immunized with TMG or TSG responded to most tick stages or tissue antigens, whereas repeated infestation sera showed the lowest response among the three groups.

Animals↗
PubMed2000

Performance of female Rhipicephalus sanguineus (Acari: Ixodidae) fed on dogs exposed to multiple infestations or immunization with tick salivary gland or midgut tissues.

This investigation compared the effects of repeated infestations to immunization of dogs with tick salivary gland or midgut extracts on the feeding and fecundity performances of female Rhipicephalus sanguineus (Latrielle). In each immunized group, three tick-naive dogs were immunized three times with tick salivary gland or midgut extracts, and twice challenged at 21-d intervals by allowing 80 female and 40 male adult ticks to feed on each host. The repeated infestation group of three naive dogs was infested five times at 21-d intervals by the same numbers of ticks. The repeated infestation group showed a trend of reduced tick performance after the third infestation, but some of the tick performance parameters had recovered by the fifth infestation. Tick attachment was reduced by immunization with either tick salivary gland or midgut extract. Immunization with tick salivary gland extract had the greatest impact on the feeding period and engorgement weight of the female ticks. Immunization with tick midgut extract resulted in the greatest reduction of tick fecundity parameters, which included preoviposition, oviposition, and egg-incubation periods in addition to reduced egg production and egg viability. These results confirm that dogs can become resistant to R. sanguineus, and demonstrate that immunization with tick salivary gland or midgut extract has different effects on tick feeding and fecundity.

Animals↗
PubMed1998

Demographic and needs assessment survey of animal care and control agencies.

OBJECTIVE: To characterize demographic and needs assessment information for animal care and control agencies in Ohio. DESIGN: Mail survey. SAMPLE POPULATION: 222 animal care and control agencies. PROCEDURE: A questionnaire was mailed to animal care and control agencies in Ohio. Data were collected for 1996. RESULTS: Of 222 agencies contacted, 180 (81%) responded. Agencies estimated that they spent $28.4 million ($2.47/person). Approximately 339,207 animals were taken in, comprising 214,143 (63%) dogs, 114,877 (34%) cats, and 10,187 (3%) wildlife or other species. Of these animals, a fourth were adopted, about a tenth were reclaimed by their owners, and two thirds were euthanatized. Approximately 302,589 animal control complaints were received, and 22,053 (7%) citations were issued. One hundred three (57%) agencies reported 25,564 cruelty complaints; criminal charges were filed for 543 (2%) cases, with 445 (82%) resulting in guilty verdicts. Among 155 agencies that provided information, 87 (56%) had spay/neuter policies. Only 69 of 178 (39%) agencies reported an association with a veterinarian. Less than half (64/150; 43%) of the agencies administered vaccinations, and 69 of 152 (45%) treated animals for intestinal parasites. The top 5 things needed by agencies were capital/facility improvements, increased funding, improved legislation for animals, educational needs, and veterinary services. CLINICAL IMPLICATIONS: In Ohio in 1996, 9.9% of dogs and 4.5% of cats received care or assistance from animal care and control agencies. Only 39% of animal care and control agencies have an association with a veterinarian.

Animal Welfare↗
PubMed1993

Serological titers of equine monocytic ehrlichiosis associated with gastro-intestinal disorders and serological follow-up on two endemic farms.

The purpose of this work was to study the association of positive serological titers to Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME) with gastro-intestinal disorders in hospitalized horses referred to The Ohio State University College of Veterinary Medicine Teaching Hospital (OSU VMTH). In addition, serological titers for E. risticii were monitored in two horse populations with endemic EME for one season to monitor temporal changes in titers. A statistically significant difference was found between the proportion of the total hospitalized horse population presented with a gastro-intestinal disorder during the study period, and study horses with IFA titers > or = 1:80 with these signs (P < 0.05). No such difference was found between the proportion of the total hospital horse population presented with signs of gastro-intestinal disorder, and the study horses with IFA titers of 1:20-1:40 with these signs, suggesting that these titers may not have any clinical significance for EME (P > 0.05). Thirty-eight horses on two farms endemic for EME were tested approximately every 3 weeks, 33 of which were tested serially at least two times. Five of the 38 horses (13.2%) had IFA titers > or = 1:80--two that were positive initially and three that seroconverted during the study; 15 horses' titers fluctuated between negative (IFA titers < 1:20) and exposed titers (1:20 through 1:40); and 18 horses remained negative throughout the study.

Animals↗
PubMed1991

IgG response in guinea pigs to Trichinella spiralis infection.

An enzyme-linked immunosorbent assay (ELISA) using excretory-secretory antigens was developed to study the dynamics of the IgG antibody response to varying levels of Trichinella spiralis infection in the guinea pig. Four groups of four Hartley guinea pigs each were infected with 1250, 250, 50 or 10 T. spiralis infective muscle larvae. They were bled every 15 days for 6 months and the IgG antibody response determined by ELISA. The time of seroconversion was dose dependent as the larger the dose, the earlier the response occurred. Significant differences in antibody response between the dose groups were evident at 30 days post-infection (P less than 0.05). Beyond 60 days post-infection, the response was similar in the four groups. The antibody response in the groups infected with 250 and 50 infective larvae was similar, but was significantly different from that of the high (1250) and low (10) dose groups from 30 days post-infection (P less than 0.01). Once seroconversion occurred, the antibody titer rose to the same level, irrespective of the initial dose. To compare the antibody response according to muscle larvae recovered, the guinea pigs were grouped into four categories: less than 10 larvae; 10-25 larvae, 50-80 larvae, greater than 100 larvae. A significant positive correlation (P less than 0.05) was observed at 60 days post-infection when these groups were compared.

Animals↗
PubMed1990

Serosurvey of horses with evidence of equine monocytic ehrlichiosis.

In August 1986, an extensive serosurvey for prevalence of IgG and IgM antibodies against Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME), was performed at 2 Ohio racetracks, River Downs (RD) and Beulah Park (BP). Of 840 horses at RD and 574 at BP, 13 and 20%, respectively, were IgG antibody-positive (by indirect fluorescent antibody test results), with antibody titer ranging from 1:20 to 1:10,240. The titer observed at highest frequency at both racetracks was 1:80. A higher proportion of horses was ill at RD (operating during the summer months) than at BP (winter track). Of ill horses, 41% (24/58) at RD and 58% (11/19) at BP were seropositive. At RD, 70% (589/840) of all horses and 95% (102/107) of IgG seropositive horses had been stabled only at RD during the month prior to testing. Analysis of these sera by use of an ELISA to detect IgM antibody against E risticii antigen indicated that at RD, 42% (57/137) of the seropositive horses were IgM seropositive. At BP, 17% (20/120) of seropositive horses were IgM seropositive. The larger number of IgM seropositive horses at RD indicates that more horses were recently infected at RD than at BP (P = 0.0001). Therefore, at least half the seropositive horses at RD seemed to have acquired the infection at RD. These serosurvey data also indicate that at BP and RD, 78% (85/109) and 91% (111/122) of IgG seropositive horses, respectively, had subclinical infection. At less than or equal to 1:40 titer, there was no difference in seropositive rates between healthy and ill horses.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Solubilization of a 5-HT3 binding site from rabbit small bowel muscularis membranes.

A 5-HT3 binding site, with high affinity for (S-)[3H]zacopride, was solubilized from rabbit small bowel muscularis membranes utilizing 0.5% sodium cholate and 400 mM (NH4)2SO4. Approximately 72% of the (S-)[3H]zacopride binding activity was recovered in a form that retained the high affinity (Kd = 0.7 nM) and specificity for this radioligand that is characteristic of the membrane-bound receptor. ICS 205-930 and other 5-HT3 compounds were effective inhibitors and exhibited the same rank order of potency in the solubilized and membrane-bound preparations. The receptor-detergent complex did not sediment after centrifugation for 1 h at 150,000 x g and eluted between thyroglobulin (MW = 669,000) and apoferritin (MW = 443,000) when fractionated by high-performance liquid chromatography gel filtration. This is the first report of the solubilization of a 5-HT3 binding site.

Animals↗
PubMed1990

Antagonism of [3H]zacopride binding to 5-HT3 recognition sites by its (R) and (S) enantiomers.

[3H]Zacopride exhibits high affinity (Kd less than or equal to 1 nM) for 5-HT3 binding sites (inhibited by ICS 205-930) in rabbit intestinal muscularis and vagus nerve, human jejunum, rat intestinal muscularis and rat brain cortex. Its binding was inhibited by several 5-HT3 antagonists that displayed similar rank orders of potency in the tissues examined. Zacopride's (S) enantiomer was significantly more potent than its (R) enantiomer (21- to 42-fold in rabbit and human; 8- to 12-fold in rat) as an inhibitor of [3H]zacopride binding. These studies indicate that the utility of [3H]zacopride as a high affinity 5-HT3 ligand resides with the (S) enantiomer.

Animals↗
PubMed1990

Nerve growth factor induces 5-HT3 recognition sites in rat pheochromocytoma (PC12) cells.

In rat pheochromocytoma (PC12) cells, nerve growth factor (7S NGF) induced the expression of recognition sites that bind the specific 5-HT3 antagonist (S-) [3H]zacopride. Culturing PC12 cells for 8-12 days in the presence of 50 ng/ml NGF increased the density (Bmax) of (S-) [3H]zacopride binding sites in cell membranes (0-100,000 x g fraction) from 0 to 105 fmoles/mg protein. This binding exhibited high affinity for (S-) [3H]zacopride (Kd = 0.8 nM), was specific (greater than 95%), and was inhibited by 5-HT3 compounds with a rank of potency (quipazine greater than ICS 205-930 greater than GR38032F greater than BRL24924 approximately MDL 72222 greater than phenylbiguanide greater than or equal to serotonin greater than 2-methyl-serotonin greater than metoclopramide) which was distinct from neuroblastoma cells. Thus, NGF-differentiated PC12 cells possess a 5-HT3 receptor and should be useful to investigate its regulation and biochemical mechanism of action.

Adrenal Gland Neoplasms↗
PubMed1989

Association of [3H]zacopride with 5-HT3 binding sites.

An assay was developed for [3H]zacopride binding to 5-HT3 specific sites in membranes from rabbit ileum muscularis. The binding was rapid, saturable, reversible, salt-insensitive, unaffected by pH between 6.5 and 9.5, and of high affinity (apparent KD = 0.65 +/- 0.15 nM). ICS 205-930, a potent 5-HT3 antagonist that inhibited competitively, was utilized to define 5-HT3 specific binding. Other 5-HT3 antagonists and agonists, although exhibiting marked differences in potency, were also effective inhibitors; whereas, antagonists of other classes of serotonin receptors, guanyl nucleotides and numerous receptor-specific ligands, including peptide hormones, were inactive. Vagus nerve exhibited the greatest amount of 5-HT3 specific binding amongst rabbit tissues and virtually all of the [3H]zacopride was bound to 5-HT3 binding sites. In rabbit, rat and ferret a fairly uniform distribution of 5-HT3 binding sites was observed along the muscularis of the small bowel. [3H]Zacopride is a high-affinity ligand for detecting 5-HT3 binding sites and rabbit small bowel muscularis membranes are a sensitive system for evaluating the potency of 5-HT3 antagonists or agonists.

Animals↗
PubMed1989

[3H]zacopride binding to 5-hydroxytryptamine3 sites on partially purified rabbit enteric neuronal membranes.

5-Hydroxytryptamine3 (5-HT3) receptors are present in both central and peripheral neuronal tissues but radioligand binding studies have thus far been limited to crude membranes from brain and vagus nerve. The present studies describe the isolation and characterization from the rabbit small bowel of neuronal membranes enriched in binding sites for the potent 5-HT3 ligand, [3H]zacopride. The number of specific [3H]zacopride binding sites per milligram of protein was increased 6-fold in a 10,000 to 100,000 x g membrane fraction as compared to the homogenate. [3H]Zacopride bound to these membranes with high specificity (greater than 90%), exhibited high affinity for a homogeneous population of binding sites (Kd = 0.3 nM) and its binding was inhibited competitively by other 5-HT3 compounds with the following rank order of potency: ICS 205-930 greater than GR 38032F greater than or equal to quipazine greater than BRL 24924 approximately MDL 72222 much greater than metoclopramide greater than 2-CH3-5-HT3. On a discontinuous sucrose gradient, specific [3H]zacopride binding was increased an additional 3.5-fold and copurified with three plasma membrane markers. Fractionation on a continuous sucrose gradient demonstrated that specific [3H]zacopride binding was associated with the enteric neuronal plasma membranes. Comparative studies in rabbit vagus nerve also demonstrated a large number (maximum binding = 148 fmol/mg of protein) of high affinity [3H]zacopride binding sites (Kd = 0.4 nM), in membranes that exhibited a density and binding characteristics similar to those from enteric neurons. Thus, membranes enriched in 5-HT3 binding sites can be isolated from both enteric and vagus neurons and [3H]zacopride is a potent ligand useful for characterization of these sites.

Animals↗
PubMed1989

Comparison of two methods for isolation of Mycobacterium paratuberculosis from bovine fecal samples.

Fecal samples from 131 cattle clinically suspect for paratuberculosis were cultured bacteriologically, using the traditional sedimentation processing method and a processing method that included a centrifugation step. Of 16 samples that were contaminated, 6 were culture-positive on at least 1 medium and by 1 processing method. Ten of 131 (7.6%) fecal samples processed by both methods were lost because of contamination. The number of culture-positive samples (using both processing methods) were 65 of 121 (53.7%) on media without miconazole and 60 of 121 (49.6%) on media with miconazole. Seven of the 121 (5.8%) samples were culture-positive, using centrifugation, after 16 weeks' incubation at 37 C. Thirteen of 60 (21.7%) isolates were obtained only with centrifugation, and 10 of these had low colony counts, suggesting that a centrifugation step may have concentrated microorganisms that would have gone undetected without centrifugation. Six of 60 (10%) isolates positive for M paratuberculosis on the sedimentation method were negative on the centrifugation method. Contamination rates were significantly (P less than 0.001) increased when centrifugation was used. The miconazole significantly (P less than 0.001) decreased contamination rates when centrifugation was used.

Animals↗