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Biomedical subjects

W Jarrett

Publications and source records attributed to W Jarrett.

At least 19 recordsLinked to original sources
PubMed1992

A sensitive assay for detection and measurement of neutralising antibody to human immunodeficiency virus.

An assay based on the inhibition of syncytium formation in C8166 cells was developed to measure low levels of neutralising antibody (NT-AB) to human immunodeficiency virus (HIV) and to detect cross-reactivity between virus strains. The relationship between virus challenge and antibody titre was represented by a tripartite curve which was essentially linear over moderate levels of virus input. Based on these findings, antibody titres were standardised against 100 TCID50 of challenge virus. However, lower virus inocula were found to detect minimum levels of antibody. Reproducibility of antibody titres between tests was high, with variation generally lying within one dilution step. The improved sensitivity of the technique allowed detection of NT-ABs in animals immunised with immune-stimulating complexes (ISCOMS) incorporating HIV antigens. Consistent levels of cross-reactivity between HIV strains was demonstrated, indicating the presence of distinct viral groups, from which dominant isolates may be chosen for use in vaccination studies.

Animals↗
PubMed1989

Induction of virus-producing tumours in athymic nude mice by bovine papillomavirus type 4.

Bovine papillomavirus type 4 (BPV-4), the causative agent of alimentary papillomatosis, has been used to infect, in vitro, fragments of palatine mucosa from late term bovine fetuses. These small explants were placed beneath the renal capsule of athymic nude mice where they grew to produce, at first, squamous epithelial cysts containing BPV-4 genomic DNA and, later, papillomas which were morphologically identical to those of cattle and which contained large amounts of replicating virus. The possible utility of this technique in assessing neutralising antibodies in vaccine development is discussed.

Animals↗
PubMed1976

Lack of tearing after Le Fort I osteotomy.

An unusual complication of lack of tearing after a Le Fort type I osteotomy for maxillary retrusion has been presented. A definite cause for the complication can only be postulated. The possibilities of this problem occurring may be prevented by more delicate use of osteotomes in the separation of the pterygoid plates.

Adult↗
PubMed1975

Vaccination against feline leukaemia virus using a cell membrane antigen system.

Cats inoculated with live feline lymphoblastoid cells of the FL74 line developed high titres of antibody to feline oncornavirus-associated cell membrane antigen (FOCMA). Eight cats were subsequently challenged with a large dose of feline leukaemia virus (FeLV) of a highly pathogenic strain. All resisted infection while 10 cats given the challenge virus alone became infected. The FeLV produced by FL74 cells was shown to be of extremely low infectivity in cats and in cultured feline cells. Cats inoculated with either FL74 cells or virus purified from them did not become infected. The purified virus did not induce FOCMA antibody in cats not previously exposed to FeLV. The fact that FL74 cells are highly immunogenic, but produce virus of low infectivity, is of value in devising vaccines against FeLV. Cats were also inoculated with FL74 cells which had been inactivated with paraformaldehyde. They developed FOCMA antibody, reaching a peak titre of 256, and no virus could be cultured either from the vaccine preparations or from the tissues of the cats.

Animals↗
PubMed1975

Epidemiological studies on feline leukaemia virus infection. I. A serological survey in urban cats.

A survey of the incidence of feline leukaemia virus (FeLV) infection in cats in a large urban area was made by studying the prevalence of antibodies to feline leukaemia virus-associated cell membrane antigens. Two serological tests were used, immunofluorescence and a mixed immunoglobulin rosette technique. The overall incidence of cats with antibodies was 40%, contrasting with 6% in the surrounding rural area. Only 6% of urban kittens were positive while 50% of adults had antibodies. The incidence in adults rose from 29% at 5-6 months to 74% in cats over 3 years. Stray cats had an incidence twice as high as that of domestic pets. These results support and extend earlier findings that FeLV infection is common and is horizontally transmitted.

Age Factors↗
PubMed1975

Anemia associated with feline leukemia virus infection in cats.

The types of anemia associated with natural and experimental feline leukemia virus (FeLV) infection in cats were investigated. In one experiment, 10 kittens were inoculated neonatally with Jarrett FeLV-1, an isolate of subgroup A; 6 developed anemia a few weeks later. This anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. Anemia was transient and nonfatal and occurred before the onset of lympoid malignancy. The same type of anemia was also seen in 9 of 24 kittens inoculated with Jarrett FeLV-9 of subgroups A and B. A different form of anemai occurred in another experiment in which 10 kittens were inoculated with FeLV-C of subgroup C only. All 10 kittens developed a profound aplastic or erythroblastopenic anemia in which the bone marrow became depleted of erythroid tissue; all kittens died within 16 weeks, most as a direct result of anemia. In an experiment in which kittens were inoculated with FeLV-B of subgroup B only, no kitten showed anemia. Cats with naturally acquired, nonleukemic lymphosarcoma were also studied. Of 33 lymphosarcomas in which myelophthisis was excluded as a cause, 54% of the affected cats had anemia, the features of which were consistent with hemolytic origin. When virus could be grown from these lymphosarcomas, it was of subgroup A alone or a combination of A and B. With one exception, anemic cats had low or negative titers to feline oncornavirus-associated cell membrane antigens. Until more isolates have been tested, it is not known if the various hematologic changes reflected differences in the pathogenic effects of the subgroups of the virus or of types of strains within them.

Anemia↗
PubMed1975

B and T cells in a cat with thymic lymphosarcoma.

The mixed antiglobulin reaction and the formation of nonimmune rosettes with guinea-pig red blood cells (RBC) distinguished feline B and T cells, respectively. In a cat with thymic lymphosarcoma, the cells reacting in these tests formed separate, nonoverlapping populations. The malignant cells were large lymphoblasts replacing the normal thymus and infiltrating local lymph nodes, where they localized only in the paracortical, i.e., thymus-dependent areas. Cells from the nodes could therefore be identified as malignant or normal by their size. The mixed antiglobulin reaction showed that the malignant cells did not carry the surface Ig characteristic of B cells, whereas these malignant cells formed nonimmune rosettes with guinea-pig RBC. Among lymph node cells, most surviving normal and small lymphocytes, from outside the thymus-dependent areas, reacted as B cells. The morphologic evidence therefore corroborated the test results, which indicated that the formation of rosettes with guinea-pig RBC seems a reliable means for the demonstration of T cells in the cat.

Animals↗
PubMed1975

Odontogenic myxofibroma: report of two cases.

We have reported the occurrence of two odontogenic mesenchymal tumors of the jaws. Though both cases had an associated impacted tooth, neither had foci of epithelial growth. Results of clinical, radiographic, and histopathological analysis in both cases were consistent with the diagnosis of a fibroma with myxomatous degeneration and thus, the diagnosis was myxofibroma.

Adolescent↗
PubMed1975

A mixed-immunoglobulin rosette technique for detection of antibody to feline oncornavirus-associated cell membrane antigen.

A mixed-immunoglobulin rosette technique has been developed for the detection of antibodies to feline oncornavirus-associated cell membrane antigens. Lymphoblastoid cells infected with feline leukemia virus were incubated with test sera and then fixed in paraformaldehyde. They were then exposed to a rabbit anti-cat immunoglobulin G serum. Antigen-antibody reactions were detected by mixing the cells with sheep erythrocytes sensitized with cat anti-sheep red blood cell serum; the presence of cat antibody on the lymphoid cells was registered by the formation of sheep red blood cell rosettes around them. The method was shown to be at least 10 times more sensitive than indirect immunofluorescence. A high degree of correlation was shown between the mixed-immunoglobulin rosette and indirect immunofluorescence tests, using both feline leukemia virus-infected cat and dog cells as targets. The results indicate that the tests are likely to be measuring similar reactions. Using the indirect immunofluorescence test we found that 75% of cats with lymphoid neoplasia had no demonstrable antibodies. Twenty-four of such indirect immunofluorescence-negative sera were tested by the mixed-immunoglobulin rosette technique; antibody was shown in at least seven of these sera.

Animals↗
PubMed1975

Feline oncornavirus-associated cell membrane antigen. II. Antibody titers in healthy cats from household and laboratory colony environments.

Antibody titers to the feline oncornavirusassociated cell membrane antigen (FOCMA) were determined for 447 healthy cats from laboratory colony and household environments. Only 2.7 percent of 221 cats from colony environments were antibody positive as compared to 50.4 percent of 256 cats from household environments. Incidence of FOCMA antibody and geometric mean antibody titer for pet cats from New York City representing single cat apartment habitats were substantially lower than values for unscreened cats from the Boston, Glasgow, and Detroit suburban environments. Geometric mean antibody titer for young adults in the Boston population was significantly higher than titers for kittens or aged cats. This may be due to greater mobility resulting in increased exposure to other cats. In contrast to the high frequency of FOCMA antibody positivity in pet-cat populations, less than 2 percent of the same groups were positive for virus group-specific antigen in peripheral blood leukocytes and platelets. This was interpreted as an indication that many more cats became infected with feline leukemia virus under natural conditions that the number developing persistent virus infection and/or clinical leukemia.

Animals↗
PubMed1975

Feline oncornavirus-associated cell membrane antigen. IV. Antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases.

Cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (FOCMA). Geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. Lymphatic leukemia and thymic lymphoma were most common in Boston, whereas alimentary lymphoma was most frequent in Glasgow. No significant differences were found in geometric mean FOCMA antibody titers for the various forms of leukemia-lymphoma or for feline leukemia virus (FeLV)-positive as compared to FeLV-negative cats. Approximately 70% of 76 Boston cats with nonregenerative anemias were FeLV gs antigen (gsa) positive; this was similar to the percentage with leukemia-lymphoma from the same population that was positive. Fifty-five to 62% of the Boston cats with other infectious diseases, such as peritonitis and septicemia, were gsa positive. We postulate that this is due to a predisposition to infectious diseases by the immunosuppressive action of FeLV. Young cats from the Boston population that developed lymphoma, infectious peritonitis, and certain other diseases were more likely to be FeLV gsa positive than older cats with the same diseases.

Age Factors↗