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Biomedical subjects

J B Katz

Publications and source records attributed to J B Katz.

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

Intracerebral transmission of scrapie to cattle.

To determine if sheep scrapie agent(s) in the United States would induce a disease in cattle resembling bovine spongiform encephalopathy, 18 newborn calves were inoculated intracerebrally with a pooled suspension of brain from 9 sheep with scrapie. Half of the calves were euthanatized 1 year after inoculation. All calves kept longer than 1 year became severely lethargic and demonstrated clinical signs of motor neuron dysfunction that were manifest as progressive stiffness, posterior paresis, general weakness, and permanent recumbency. The incubation period was 14-18 months, and the clinical course was 1-5 months. The brain from each calf was examined for lesions and for protease-resistant prion protein. Lesions were subtle, but a disease-specific isoform of the prion protein was present in the brain of all calves. Neither signs nor lesions were characteristic of those for bovine spongiform encephalopathy.

Animals↗
PubMed1994

Isolation of pseudorabies (Aujeszky's disease) virus from a Florida panther.

Pseudorabies virus was isolated in cell culture from the brain tissue of a 3.5-year-old male Florida panther (Felis concolor coryi). The virus was not isolated from other tissues collected at necropsy. Based upon a nested polymerase chain reaction (PCR), the virus was determined to have the classical wild-type virulent genotype, glycoprotein I+ (gI+) and thymidine kinase+ (TK+).

Animals↗
PubMed1994

'Vienna in the wheat fields': psychoanalysis in Topeka.

From its beginning, the Topeka Institute for Psychoanalysis has had a unique relationship with The Menninger Clinic. The author sketches some highlights of this mutually enhancing connection, and then introduces the papers in this issue celebrating the Institute's 50th anniversary.

Academies and Institutes↗
PubMed1993

Sensitive identification of bluetongue virus serogroup by a colorimetric dual oligonucleotide sorbent assay of amplified viral nucleic acid.

A polymerase chain reaction (PCR) procedure coupled to an enzyme-linked oligonucleotide sorbent assay (ELOSA; a PCR-ELOSA) identified all 24 serotypic variants of bluetongue virus (BTV) without identifying any of six viruses belonging to the related epizootic hemorrhagic disease virus serogroup. The PCR-ELOSA detected 0.01 50% cell culture infectious doses of each serotype of BTV. The sensitivity and serogroup-wide specificity of the PCR-ELOSA may enable it to replace the more expensive, time-consuming, and biohazardous methods used in the identification of BTV.

Base Sequence↗
PubMed1993

Presumptive diagnostic differentiation of hog cholera virus from bovine viral diarrhea and border disease viruses by using a cDNA nested-amplification approach.

Hog cholera virus (HCV), bovine viral diarrhea virus (BVDV), and border disease virus (BDV) are closely related pestiviruses. BVDV and BDV are found worldwide but seldom cause disease in swine. In contrast, HCV has been successfully eradicated from swine in several nations but poses a potentially devastating threat to them because of its great virulence. Rapid differential diagnosis of HCV from BVDV and BDV infections in swine is vital for detection of the possible reintroduction of HCV into national herds from which it has been eradicated. Nested polymerase chain reactions (PCRs) for each of two pestiviral genomic segments are described. Amplification of the relatively conserved 5' genomic terminus identified 59 of 61 HCV, BVDV, and BDV isolates generically as pestiviruses. Nested amplification of the second region was designed to differentiate HCV from BVDV and BDV by exploiting relatively conserved differences in the nucleotide sequences that encode the major envelope glycoprotein. This second PCR correctly identified 36 of 36 diverse HCV isolates while failing to recognize any of 25 BVDV and BDV isolates. Multiple restriction fragment length analyses confirmed the identities of both external and nested PCR products. The two sets of PCRs may help confirm the generic identity of most pestiviruses and may permit presumptive differential diagnosis of HCV from BVDV and BDV.

Animals↗
PubMed1993

Colorimetric diagnosis of prolonged bluetongue viremia in sheep, using an enzyme-linked oligonucleotide sorbent assay of amplified viral nucleic acids.

Each of 5 US-origin serotypes of bluetongue virus (BTV) was inoculated into a separate pair of sheep. The duration of each animal's ensuing viremia was monitored, using a BTV serogroup-specific nested polymerase chain reaction (PCR) method and an embryonating chicken egg (ECE) inoculation procedure. Mean duration of viremia was 100 and 38 days for the PCR and ECE methods, respectively. This difference was significant (P < 0.001) and documents a more prolonged viremia in virus-exposed sheep than has been reported. A dual internal oligonucleotide solution hybridization procedure was developed for the rapid (2 hours) colorimetric detection and identification of BTV-specific PCR products. This enzyme-linked oligonucleotide sorbent assay (ELOSA) relied on annealing of separate biotinylated and fluoresceinated probes to the amplified BTV nucleic acid; these complexes were captured on streptavidin-coated microtitration wells and were detected, using a horseradish peroxidase-labeled antifluorescein antibody conjugate. End-point dilution analyses of PCR products indicated that the ELOSA was more sensitive than gel electrophoretic or comparable colorimetric slot-blot hybridization techniques. The BTV PCR-ELOSA system represents a more sensitive and expeditious means of diagnosing BTV-induced viremia than does the ECE procedure currently used. The combination of ELOSA with PCR should facilitate practical application of nucleic acid technology to diagnostic veterinary medicine.

Animals↗
PubMed1992

Molecular analysis of pseudorabies viral vaccines and their rapid differentiation from wild-type isolates using DNA-amplified glycoprotein I and thymidine kinase gene segment polymorphisms.

Several conventional and genetically recombinant modified-live viral (MLV) vaccines are used to control pseudorabies virus infections (Aujeszky's disease, PRV) in swine. Differentiating vaccinal PRV (V-PRV) from wild PRV (WT-PRV) is important for herd health, regulatory and forensic purposes, and for studies of PRV latency and epidemiology. All PRV vaccines used currently contain glycoprotein I (gI) and/or thymidine kinase (TK) gene deletions, whereas WT-PRV typically contain intact gI and TK genes. Utilizing these differences we developed an effective but simple differential polymerase chain reaction (PCR) approach based upon the amplification of gI and TK gene polymorphisms. The primary immunoreactive epitope-encoding region of the gI gene and nearly the entire TK gene were amplified and analyzed using nested PCR procedures. TK and gI PCR products were cleaved with Sal I and Sac I, and Nco I restriction enzymes respectively. PCR product and restriction fragment length polymorphisms enabled most V-PRV to be clearly distinguished from each other, and all of them, as a group, clearly differentiated from typical WT-PRV. Mixtures of V-PRV and WT-PRV could be identified as such. The uncommon but occasional occurrence of atypical WT-PRV containing altered gI and/or TK genes indicates the need for interpretive caution, particularly if aberrant gene segment polymorphisms are observed. This rapid and precise molecular approach will facilitate regulatory monitoring, epidemiological investigations, diagnostic differentiation, purity testing and latency/recrudescence studies with the class of biologicals and offers a model for similar analyses of other MLV biologicals as well.

Animals↗
PubMed1992

The role of somatic mutation in the pathogenic anti-DNA response.

Anti-DNA antibodies represent a significant autospecificity in systemic lupus erythematosus because they are essentially diagnostic of the disease and they contribute to renal pathology. The molecular genetic characterization of these antibodies from both lupus-prone mice and humans with lupus has shown them to be somatically mutated. In many cases the nature of the mutations suggests that DNA or some structurally homologous molecule is driving the response. In other cases the high replacement-to-silent mutation ratio in framework regions of the antibody suggests selection by idiotype or by some mechanism other than antigen itself. Current studies of immunoglobulin variable region genes encoding anti-DNA antibodies reveal no disease associated polymorphisms. There are also no data suggesting that the nature of the recombination process that forms intact variable region genes or of the process of somatic mutation differs in autoimmune and nonautoimmune strains or kindred. Current data suggest, rather, that a defect in regulation is responsible for auto-antibody production in SLE. The finding that most if not all anti-double stranded DNA antibodies are somatically mutated suggests the defect is in maintenance of peripheral rather than central tolerance.

Animals↗
PubMed1992

Analysis of glycoprotein I (gI) negative and aberrant pseudorabies viral diagnostic isolates.

Glycoprotein I (gI) phenotypes and genotypes of 4 pseudorabies viral diagnostic isolates were evaluated by use of in vitro DNA amplification, monoclonal antibody binding, gI-specific serodiagnostic responses, and in vivo virulence approaches. Three viruses were avirulent and did not elicit gI-specific serologic responses, react with gI-specific monoclonal antibodies, or contain gI epitope-encoding DNA sequences. The fourth virus was virulent and did elicit a gI-specific serodiagnostic response. Compared with reference virulent pseudorabies viruses, however, the fourth isolate had reduced reactivity with a group of gI monoclonal antibodies and had a single nucleotide sequence substitution with a corresponding putative amino acid change in the epitopically dominant portion of the gI molecule. Presumably, the first 3 isolates represented diagnostic recoveries of viruses derived from gI-deleted modified-live pseudorabies viral vaccines, whereas the fourth isolate was a virulent but gI-aberrant wild-type virus. Thoroughly assessing the gI status of pseudorabies viral diagnostic isolates was considered to be essential in evaluating the epidemiologic importance of these viruses and in monitoring the validity of gI-based vaccine companion tests now used worldwide in pseudorabies control and eradication programs.

Amino Acid Sequence↗
PubMed1991

Molecular characteristics of antibodies bearing an anti-DNA-associated idiotype.

Anti-double-stranded DNA antibodies are the hallmark of the disease systemic lupus erythematosus and are believed to contribute to pathogenesis. While a large number of anti-DNA antibodies from mice with lupus-like syndromes have been characterized and their variable region genes sequenced, few human anti-DNA antibodies have been reported. We describe here the variable region gene sequences of eight antibodies produced by Epstein-Barr virus (EBV)-transformed B cells that bear the 3I idiotype, an idiotype expressed on anti-DNA antibodies and present in high titer in patients with systemic lupus. The comparison of these antibodies to the light chains of 3I+ myeloma proteins and serum antibodies reveals that EBV transformation yields B cells producing antibodies representative of the expressed antibody repertoire. The analysis of nucleotide and amino acid sequences of these antibodies suggests the first complementarity determining region of the light chain may be important in DNA binding and that paradigms previously generated to account for DNA binding require modification. The understanding of the molecular genetics of the anti-DNA response requires a more complete description of the immunoglobulin germ line repertoire, but data reported here suggest that somatic diversification is a characteristic of the anti-DNA response.

Amino Acid Sequence↗
PubMed1990

Recombination in vivo of pseudorabies vaccine strains to produce new virus strains.

Herpesvirus suis (pseudorabies virus, PRV) has been the focus of intensive genetic engineering efforts and several effective genetically recombinant modified live virus PRV vaccines have resulted. The likelihood and consequences of complementation and/or genetic recombination in vivo between genetically engineered and conventionally derived vaccine strains of PRV are essentially unknown. In this study, two vaccine strains of PRV with complementary gene deletions were co-inoculated into sheep. It reports that avirulent vaccine strains of PRV (genetically engineered and conventionally attenuated) recombined in vivo, resulting in the production of a new and undesirable strain of PRV. The present study exemplifies the need for thorough assessment of genetically engineered micro-organisms in the animal environment.

Animals↗
PubMed1990

Evaluation of thymidine kinase and neomycin phosphotransferase II positive selection systems for recovery of genetically atypical and recombinant DNA vaccine viruses.

Dominant phenotypic marker cell culture selection systems were evaluated for the recovery of thymidine kinase positive (TK+), thymidine kinase negative (TK-), and neomycin phosphotransferase II positive (NPT II+) viruses. From 1 to 100 pfu of each marker-positive virus was diluted into 10(6) pfu of marker-negative background virus prior to selection. All three selection systems recovered 100 or fewer pfu of marked virus from the background population (10(-4) fractional level). In some instances, 1 to 10 pfu of marked virus were recovered (10(-5)-10(-6) fractional levels). TK+ and NPT II+ selections yielded nearly pure marker positive virus (98.8% and 99.5% respectively). Populations surviving TK- selection were significantly less pure (58.7%, P less than 0.05). Purity of recovered viruses was independent of the initial fractional level of marker-positive virus. The use of TK+, TK-, and NPT II+ selection systems is discussed in the context of purity testing and environmental surveillance of recombinant DNA viral vaccines.

DNA, Recombinant↗