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Biomedical subjects

J R Gorham

Publications and source records attributed to J R Gorham.

At least 19 recordsLinked to original sources
PubMed1992

Molecular cloning and physical mapping of bovine herpesvirus 4 strain DN 599 and comparison with two American field-isolates.

Ninety four percent of the genome of bovine herpesvirus 4 (BHV-4) strain DN 599 was cloned and a physical map was constructed by Southern blot analysis using a library of cloned fragments cleaved with the 3 restriction enzymes (Eco RI, Bam HI, and Hin dIII). The genome length was estimated to be 156.5 kbp +/- 0.7. The genome comprises a region of unique segment (114 kbp) and two flanking segments containing tandem repeats. The size of each repeat was approximately 2.35 kbp and each repeat contained one Eco RI site and two Bam HI sites. We also examined two recent American field-isolates of BHV-4 and compared the Eco RI maps of the two isolates with that of DN 599. We observed the following: (1) insertions or deletions of restriction sites at the periphery of the unique segment; (2) variation in the lengths of junction fragments; (3) variations in the lengths of hypermolar Eco RI fragments containing the repeats; and (4) the Eco RI map of one of the American field-isolates resembles the BHV-4 "Movar type" of Europe.

Animals↗
PubMed1991

Analysis of bovine herpesvirus 4 (DN 599) major antigens with monoclonal antibodies and polyclonal immune serum.

Monoclonal antibodies (MAbs) and polyclonal immune sera were produced and used to identify the major antigens of bovine herpesvirus type 4 (BHV-4). SDS-polyacrylamide gel electrophoresis of immunoprecipitates of radiolabeled lysates from infected cells resolved 24 peptide bands varying from 12 kDa to over 300 kDa. Six peptides were identified as major viral antigens by immunoprecipitation. Based on the pattern of radioimmunoprecipitation, MAbs were assigned into four groups. Group 1 precipitated a tunicamycin-sensitive glycoprotein complex which contained six components (245, 190, 152, 123, and 48/46 kDa). Deglycosylation with endoglycosidase F revealed two peptides with Mr of 93 and 38 kDa as the basic peptides of the glycoprotein complex. In addition, a 115 kDa glycopeptide containing glycan-peptide bonds of mixed type was identified. Group 2 precipitated a non-glycosylated protein complex consisting of three monomers (33/31/30 kDa). Groups 3 and 4 reacted with single monomeric non-glycosylated peptides with Mr of 48 and 14 kDa, respectively. Although none of the MAbs exhibited significant neutralizing activity, some reacted strongly in immunosorbent and/or immunohistochemical assays, suggesting they may be good candidates for use in diagnostic assays.

Animals↗
PubMed1991

Characterization of monoclonal antibodies to bovine herpesvirus type I, Los Angeles strain.

We produced monoclonal antibodies (mAbs) against bovine herpesvirus type 1 (BHV-1), Los Angeles strain, and then evaluated them as potential candidates for preparing diagnostic reagents. Of the 318 cell lines expressing antibodies to the virus, 60% (192) secreted IgG and 40% (126) secreted IgM. Twenty-six mAbs were selected based on enzyme-linked immunosorbent assay (ELISA) and virus neutralization (VN) titers and characterized by immunoprecipitation, immunofluorescence and immunoblots. The selected mAbs were assigned to one of four groups based on their immunoprecipitation patterns. Group A (4 mAbs) precipitated a complex of three glycoproteins with molecular weight (MW) 130 kDa, 72 kDa and 55 kDa, which presumably represented gI of BHV-1. Monoclonal antibodies of this group were highly reactive in ELISA but had low VN titers. Group B (4 mAbs) precipitated a glycoprotein with MW of 71 kDa (gIV). This group of mAbs had high VN titers. Group C (16 mAbs) precipitated a 97 kDa glycoprotein (gIII). Monoclonal antibodies of this group had high ELISA but low VN titers. Group D (2 mAbs) precipitated a double band of non-glycosylated proteins with MW of 37/32 kDa; these proteins could not be assigned to any of the antigens of BHV-1 previously described. ELISA and VN titers of this group of mAbs were low. To test the antigenic variability of the antigenic determinants which were recognized by these 4 groups of mAbs, we adapted Madin Darby bovine kidney cell-propagated BHV-1 Los Angeles strain to Crandell's feline kidney cell line. After the tenth passage in feline kidney cells, the epitopes on the 37/32 kDa peptide recognized by the mAbs group D were no longer detectable. Additional changes were noted in the electrophoretic mobility of the 130 kDa and 71 kDa glycoproteins (gI) identified by mAb of group A shifted downward. The 71 kDa glycoprotein (gIV) reactive with mAb group B and the 97 kDa (gIII) reactive with mAb group C remained stable. Since clone No. 191 of group B mAb was potent in ELISA, VN, immunoblots and immunofluorescence, and recognized an epitope which did not change under selective pressure, we feel that the mAb produced by this clone are a good candidate for the production of diagnostic reagents.

Animals↗
PubMed1991

A monoclonal antibody defines a geographically conserved surface protein epitope of Babesia equi merozoites.

Babesiosis is a tick-borne hemoparasitic disease affecting horses worldwide. To investigate mechanisms of immunity to this parasite, the antibody response of infected horses to Babesia equi merozoite proteins was evaluated. Immunoprecipitation of B. equi merozoite antigens with sera from infected horses revealed 11 major proteins of 210, 144, 108, 88, 70, 56, 44, 36, 34, 28, and 25 kDa. Monoclonal antibody (MAb) 36/133.97, which binds to live merozoites, immunoprecipitated proteins of 44, 36, 34, and 28 kDa. When immunoprecipitations were performed with in vitro translation products of merozoite mRNA, MAb 36/133.97 immunoprecipitated proteins of 38, 28, 26, and 23 kDa which comigrated with proteins immunoprecipitated by sera from infected horses at 10(-3) to 10(-4) dilutions. In Western blot analysis, MAb 36/133.97 recognized proteins of 44, 36, 34, and 28 kDa, and a 28-kDa protein was identified by sera from infected horses at a dilution of 10(-4). MAb 36/133.97 bound to B. equi isolates from Florida and Europe. Furthermore, the binding of MAb 36/133.97 to merozoite proteins was inhibited by sera of infected horses from 19 countries. Collectively, these data indicate MAb 36/133.97 binds to a geographically conserved peptide epitope on multiple B. equi merozoite proteins, including a merozoite surface protein, and MAb 36/133.97 reacts with a B. equi protein immunodominant in infected horses.

Animals↗
PubMed1990

Prevalence and effect of subclinical ovine progressive pneumonia virus infection on ewe wool and lamb production.

The prevalence of infection with ovine progressive pneumonia (OPP) virus and its effects on ewe wool and lamb production were investigated in a flock of 2,976 ewes of 6 breed types (Rambouillet, Targhee, Columbia, Polypay, 1/4 cross Finnsheep, and 1/2 cross Finnsheep). Prevalence of seropositivity was significantly (P less than or equal to 0.01) lower among Rambouillet and Targhee breeds (44 and 42%, respectively), intermediate in Polypay, Columbia, and 1/4 cross Finnsheep (approximately 53%), and higher among 1/2 cross Finnsheep (62%). Seropositivity increased with age in all breed types from 11% at 1 year of age to 93% at greater than or equal to 7 years of age. Lateral disease transmission is indicated by linear increase of seropositivity prevalence with increasing age, including that in sheep greater than 6 years old. Subclinical infection with OPP virus had no apparent detrimental effect on number of lambs born, lamb viability, birth weight, number of lambs weaned, or growth rate of single and twin lambs, compared with findings for noninfected sheep in the same flock. Mature ewe body weight and grease fleece weight did not differ between subclinically infected seropositive and seronegative ewes. Subclinical infection with OPP virus does not appear to have an adverse economic effect on ewe wool and lamb production. Culling rate attributable to clinical manifestation of infection with OPP virus must be accurately determined before the true effects of virus infection on production can be determined and an eradication program can be recommended.

Age Factors↗
PubMed1990

Comparison of a DNA probe, complement-fixation and indirect immunofluorescence tests for diagnosing Anaplasma marginale in suspected carrier cattle.

Most estimates of the prevalence of anaplasmosis have been based on serologic data using the complement-fixation (CF) and/or card agglutination tests. Since these tests are considered to be only about 50 percent reliable for detecting carrier cattle in enzootically stable herds, the need for more sensitive diagnostic tests is widely recognized. The objective in the present study was to compare the sensitivity of the CF test with that of the indirect immunofluorescence (IIF) test and a recently developed DNA probe in determining the prevalence of Anaplasma marginale infection in cattle from an enzootic area. The study herd consisted of 52 8-month-old steers and 13 3-year-old cows of mixed beef breed. All cattle were initially tested for this comparative purpose. All but one animal (one that was a positive reactor as assessed by all three tests, and served as a positive control), were treated with long-acting oxytetracycline in an attempt to clear any carrier infections. Each animal was then retested at 1 month and 2 months post-treatment (PT), in an effort to determine if the DNA probe could be used to evaluate the effectiveness of the drug. Six of the 65 (9.2%) initial serum samples were CF positive. In contrast, 60 (92.3%) and 64 (98.5%) of the samples were positive as assessed with the IIF test and the DNA probe, respectively. The DNA hybridization reactions varied in intensity within the sample population indicating different individual levels of infection. The DNA probe hybridized with two samples taken at 1 month PT, and with two different samples taken at 2 months PT. The mean IIF titers were reduced at both the 1 month and 2 month sampling times. These results suggest that the drug did not eliminate infections in all cattle. Some may have been cleared, but, in any event, the drug did reduce the level of infections below the sensitivity of the DNA probe and interrupted continuity of stimulation of antibody. Therefore, the DNA probe and the IIF test appear to be considerably more sensitive in detecting carrier infections than the CF test, and should be considered in future epidemiologic studies.

Anaplasma↗
PubMed1990

Organ-specific modification of the dose-response relationship of scrapie infectivity.

The dose-response relationships of scrapie strain 263K-infected hamster brain and spleen homogenates were compared to determine if intracerebral end-point titrations of infectivity in these homogenates were measures of the same pathogenic phenomenon. Analysis of the dose-response curves indicated that the average increase in incubation period per 10-fold dilution (i.e., the dilution kinetics) of brain infectivity was significantly different from that of spleen infectivity. This difference contradicted the assumption that the same pathogen or pathogenic mechanisms were responsible for producing disease in each titration. Therefore, the end-point titrations and infectivity titers of the brain and spleen homogenates were measures of two different phenomena. Subsequent passage of a scrapie-infected spleen homogenate demonstrated that the dose-response relationship of scrapie infectivity in this agent-host system was dependent on the organ titrated, not the tissue source or inoculation route of previous passage.

Animals↗
PubMed1990

Regulation of biotechnology in the United States and Canada.

The regulation of biotechnology in the United States and Canada is based on principles that reflect respect for the new technology, yet also recognize that most traditional approaches to regulation, employing sound science and common sense, still apply. Four specific principles form the framework on which regulatory schemes are based: (1) the products of biotechnology will not differ fundamentally from unmodified organisms or from conventional products; (2) the product rather than the process shall be regulated; (3) regulation should be based on the end use of the product and will be conducted on a case-by-case basis; and (4) the existing laws provide adequate authority for regulating the products of biotechnology. This report summarizes the regulatory approaches taken in various organisms and products. Special emphasis is given to: (1) issuance of entry permits for genetically-engineered plants and micro-organisms; (2) licensing of genetically-engineered veterinary biological products; and (3) permits for movement and release into the environment. A three-category classification system is described for dealing with hybridomas and recombinant-derived products, based on their biological characteristics and safety concerns. Categories range from relatively simple inactivated recombinant animal vaccines to products using live vectors to carry recombinant-derived foreign genes that code for immunizing antigens and/or other immune stimulants. This paper stresses that few fields of contemporary science and technology hold forth more possibilities and greater expectations than biotechnology. It is therefore of utmost importance that animal health officials and scientists ensure that the products of biotechnology will not cause or transmit infectious disease, adversely affect the environment or adulterate food products.

Animals↗
PubMed1990

Diagnosis of viral and bacterial diseases.

The potential contributions of techniques, such as restriction enzyme analysis, nucleic acid detection, the polymerase chain reaction and competitive inhibitive tests, are only beginning to be defined. The extraordinary promise of these procedures has yet to be fully realized. However, before these techniques are accepted and widely used, they should be shown to have sensitivity and specificity comparable to those of current tests. Finally, they should be safe, easy to conduct and automated to facilitate the study of large numbers of specimens.

Animals↗
PubMed1989

Canine parainfluenza virus-induced encephalitis in ferrets.

Young seronegative ferrets were intracerebrally inoculated with a neurotropic strain of canine parainfluenza (CPI) virus and serially killed at intervals after infection for subsequent viral immuno-peroxidase, light microscopical and scanning electron microscopical evaluation. The CPI virus infection resulted in a self-limiting non-suppurative ependymitis and choroiditis with associated ependymal cell degeneration. These changes were accompanied by paraventricular and perivascular cellular infiltrates of lymphocytes and monocytes, predominantly in the fourth ventricle and the cervical spinal cord and less frequently in the lateral ventricles and Sylvian duct. The inflammatory lesions were first detected on post-inoculation day (PID) 8 and had largely resolved after PID 22. Two animals showed multifocal axonal degeneration in the mesencephalon and vestibular nucleus, respectively. Immuno-histocytochemistry showed that virus replication was restricted to ependymal and subependymal cells and was most prominent on PID 4. No prominent residual lesions were present in convalescent animals. Virus-neutralizing CPI antibodies developed by PID 9 and increased slowly thereafter.

Animals↗
PubMed1988

Chronic disease in goats orally infected with two isolates of the caprine arthritis-encephalitis lentivirus.

Newborn Saanen goats were orally infected with two distinct biologically cloned isolates of the caprine arthritis-encephalitis lentivirus (CAEV), designated CAEV(63) (Crawford TB, Adams DS, Cheevers WP, Cork LC: Science 207:997, 1980) and CAEV (Co) (Cork LC, Hadlow WJ, Crawford TB, Gorham JR, Piper RC: J Infect Dis 129:134, 1974; Narayan O, Clements JE, Strandberg JD, Cork LC, Griffin DE: J Gen Virol 50:69, 1980). All infected goats seroconverted for antibodies to CAEV, and there were no serologic reversions. Histologic lesions consisted of chronic inflammation of variable incidence and severity in joints and mammary gland. Clinical arthritis, estimated by enlargement of carpi, correlated with severe inflammation of radiocarpal synovium. Statistical evaluations of clinical and histologic parameters indicated that chronic joint disease was significantly more frequent and more severe in the group of goats infected with CAEV(63) than in the group infected with CAEV (Co). Thus, the severity of chronic arthritis is determined in part by the relative pathogenicity of individual CAEV isolates. Analysis of the temporal development of carpal arthritis during the first 3 years of infection indicated that (a) the extent of eventual chronic disease in individual joints was apparent relatively early after infection, (b) joints with severe chronic lesions were clinically enlarged at irregular intervals and (c) the pattern of recurrent arthritis was unique for each joint. Thus, chronic arthritis develops with a progressive course which may be promoted by recrudescent inflammation. Infectious virus was recovered 3 years after infection from selected tissues of 12 of 17 CAEV(63)-infected goats and 11 of 18 CAEV(Co)-infected goats. Virus recovery was independent of the virus isolate used for experimental infection and did not correlate with the severity of lesions.

Administration, Oral↗
PubMed1988

Comparison of an enzyme-linked immunosorbent assay and a complement-fixation test for the detection of IgG to bovine herpesvirus type 4 (bovine cytomegalovirus).

An indirect ELISA for the detection of bovine immunoglobulin to bovine herpesvirus type 4 (BHV-4) was developed. Three methods of antigen preparation were compared. They included (1) BHV-4-infected Madin Darby bovine kidney (MDBK) cells treated with glycine and then frozen and thawed, (2) BHV-4-infected MDBK cells treated with glycine and then sonicated, and (3) BHV-4-infected MDBK cells treated with a detergent. The antigen preparation that gave the highest reactivity was the first method. We obtained serum samples from 178 cattle in the field and assayed the serum by ELISA and the complement-fixation (CF) test. Eighty-six percent (153) of the serum samples were positive by ELISA, and 70% (124) were positive by the CF test. The ELISA had a higher degree of sensitivity than did the CF test. Also, the ELISA was specific, and the prevalence of BHV-4-infection was more common in beef and dairy herds than previously recognized.

Animals↗
PubMed1987

Comparisons of feline panleukopenia virus, canine parvovirus, raccoon parvovirus, and mink enteritis virus and their pathogenicity for mink and ferrets.

Parvoviruses from mink (mink enteritis virus [MEV]), cats (feline panleukopenia virus [FPV]), raccoons (raccoon parvovirus [RPV]), and dogs (canine parvovirus [CPV]) were compared. Restriction enzyme analysis of the viral replicative-form DNA revealed no consistent differences between FPV and RPV isolates, but CPV and MEV isolates could be distinguished readily from other virus types. Feline panleukopenia virus, RPV, and MEV, but not CPV, replicated to high titers in mink. However, on the first passage, disease and microscopic lesions were observed only in mink inoculated with MEV. Feline panleukopenia virus and RPV isolates replicated in ferrets, but disease or microscopic lesions were not observed. Feline panleukopenia virus and RPV isolates could be passaged repeatedly in mink and ferrets. Virulence of FPV and RPV isolates was low compared with that of MEV, and only a single mink inoculated with FPV or with RPV developed clinical disease on the sixth passage of virus.

Animals↗
PubMed1978

Serologic survey of prevalence of ovine progressive pneumonia in Idaho range sheep.

Blood samples from 2,310 mature sheep in 3 Idaho range flocks were examined by agar gel immunodiffusion to determine the prevalence of ovine progressive pneumonia. The prevalence ranged from 58% for all ages combined in one flock to 90% of cull ewes in another flock. Age-specific prevalence rates increased from 16% in yearlings to 83% in ewes greater than or equal to 7 years old. Rambouillet sheep had a significantly (P less than 0.01) lower prevalence than sheep of 5 other breeds, whereas one-half Finnsheep crosses had a significantly (P less than 0.01) higher prevalence than sheep of other breeds. Within breed and age, there was no significant difference in reproductive performance between seropositive and seronegative ewes.

Animals↗