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Biomedical subjects

K Weijer

Publications and source records attributed to K Weijer.

48 records · Page 3Linked to original sources
PubMed1979

Studies on antibodies against feline leukaemia virus (FeLV) in cat sera and rabbit anti-FeLV sera: cross reaction and differences.

The indirect immunoferritin technique (IFT) that enables us to distinguish clearly whether an antibody reacts with a virus particle or only with the cell membrane, was used to study 25 cat sera and one rabbit anti-feline leukaemia virus (FeLV) serum using FL-74 cells as target. (1) All sera contained antibodies against FeLV even though 11 of the cats were viraemic at the same time; (2) from the effect of glutaraldehyde fixation of the FL-74 cells on the reaction with cat sera and the results of blocking experiments, it could be concluded that cat sera and rabbit anti-FeLV sera react partly with different antigenic specificities of FeLV, partly with the same antigens; and (3) the indirect membrane immunofluorescence test using FL-74 cells as target is not a good test to detect the presence of antibodies against feline oncornavirus-associated cell membrane antigen (FOCMA) because FL-74 cells produce a large quantity of FeLV and the fluorescence measured could be from antibodies against FeLV.

Animals↗
PubMed1978

[Control of lymphosarcoma or leukaemia in cats and of feline leukaemia virus (author's transl)].

A removal programme, specially designed for catteries or multiple cat households, to reduce the incidence of lymphosarcoma or leukaemia in cats and the spread of feline leukaemia virus (FeLV), is discussed. This removal programme includes annual testing of male stud cats, testing all contacts of FeLV-positive cats they had during the past two years, testing cats imported from abroad and isolation--or, if this is not possible, euthanasia--of cats found to be positive for FeLV-antigen. To detect the FeLV-antigen a simple indirect fluorescent antibody technique (FAT) was used to detect FeLV-antigen. During a period of four years, the following results were obtained when a removal programme was carried out by a large cat breeders' association in the Netherlands. The proportion of catteries, in which FeLV-positive cats were found to be present, decreased from 11.5 per cent in the former half of 1974 to 2.1 per cent in the latter half of 1977. The proportion of FeLV-positive cats and male studs decreased from 4.9 per cent to 1.2 per cent and from 5.9 per cent to 1.0 per cent respectively during this period. It is concluded that the recommended removal programme is a simple and successful procedure.

Animals↗
PubMed1977

Feline malignant mammary tumors. III. Presence of C-particles and intracisternal A-particles and their relationship with feline leukemia virus antigens and RD-114 virus antigens.

Thirty-six feline mammary tumors were examined by the electron microscope, and by the indirect immunofluorescence (IFA) test with anti-FeLV and anti-RD-114 serum. In 11 (30.6%) tumors intracisternal A-particles (IAP) were found. One of these tumors contained a few particles with an electron-dense nucleoid in the cisternae of the endoplasmic reticulum. In 7 (19.4%) other tumors C-particles were found and in the remaining 18 (50.0%) no particles at all could be detected. In 11 (30.6%) tumors FeLV antigens and in 20 (55.5%) tumors RD-114 virus antigens were present. In 9 (25%) tumors we found a high (greater than 1/64) and in 11 (30.6%) tumors a low (greater than 1/16 less than or equal to 1/64) titer. There was a good correlation between the presence of C-particles and the demonstration of FeLV-antigen but none between IAP and FeLV antigens. No correlation was found between RD-114 virus antigens and any type of particle. Morphologically, the IAP found in feline mammary tumors were indistinguishable from the IAP present in mammary tumors of some inbred mice strains. The IAP in feline mammary tumors possibly represent an endogenous virus, different from RD-114 virus. The role of these viruses in the etiology of feline mammary tumors is discussed.

Animals↗
PubMed1975

[The incidence of lymphosarcoma (leukaemia) and feline leukaemia virus (FeLV) in cats in the Netherlands (author's transl)].

Seven different groups of cats were examined to study the incidence and distribution of feline leukaemia virus (FeLV) in the Netherlands. The indirect fluorescent antibody (IFA) technique was used to detect FeLV antigen. Of the cats with lymphosarcoma (leukaemia), 73.2 per cent and of those with infectious peritonitis, 32.4 per cent were found to be positive for FeLV antigen. Of the sixty-six cats with other tumours, only one, a cat with carcinoma of the mammary gland; was positive for FeLV antigen. Of 557 cats with various lesions, forty-two (7.5 percent) were positive for FeLV antigen. The IFA-test was found to be a useful adjunct in establishing the correct diagnosis. Of all stud cats which had been in contact with FeLV-positive cats, 24.7 percent were positive for FeLV antigen, wheras all those which had not been in contact with these cats, were negative. There was a marked difference between the proportions of FeLV-positive cats in the groups of clinically normal cats which had (20.6 per cent) and which had not (0.4 per cent) been in contact with FeLV-positive cats. Follow-up studies showed that 67.8 percent of the clinically normal, FeLV-positive cats had died from or been sacrificed because of FeLV-associated diseases within twenty months.

Age Factors↗
PubMedDate not supplied

Aztreonam for injection (lyophilized): development of an automated solution batching process utilizing volumetric powder feeders.

As part of a commitment to fully automate the manufacture of a lyophilized dosage form of Azactam (Aztreonam for Injection), an automated solution batching procedure was developed. The lyophilization process requires solution batching of Aztreonam and L-arginine, the two constituents of the product. To avoid preblending of aztreonam and L-arginine prior to dissolution, a batching process was developed which makes use of two separate volumetric powder feeders. In conjunction with a feedback pH control system, these powder feeders provided for (a) a faster batching process, (b) a tight control of solution pH during batching, (c) a failsafe system to prevent operator error and equipment malfunction. Data are presented correlating bulk densities of various powders with feeder output along with solution pH profiles determined using the manual mode and the automated feedback pH control system.

Automation↗
PubMedDate not supplied

Feline mammary carcinomas as a model for human breast cancer. I. Sensitivity of mammary tumor cells in culture to cytostatic drugs. A preliminary investigation of a predictive test.

Feline mammary carcinomas were found to maintain well in short-term cultures. Principally the same types of nuclear DNA frequency distribution histograms were recognized in feline mammary carcinomas as in human mammary carcinomas. However, the more abnormal histograms are less frequent in feline than in human mammary carcinomas. Feline mammary carcinomas appeared, at least in vitro, most sensitive to Doxorubicin and 5-fluorouracil. Preliminary, thymidine incorporation studies indicate both cytotoxic and cytostatic effects of Doxorubicin and 5-FU. Methotrexate was found to stimulate thymidine incorporation.

Animals↗