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Biomedical subjects

A Bendich

Publications and source records attributed to A Bendich.

At least 91 records · Page 5Linked to original sources
PubMed1978

Inhibition of human seminal fluid DNA polymerase by an IgG fraction of seminal plasma from vasectomized men.

Immunoglobulin G (IgG) was isolated from ejaculates of intact and vasectomized men by precipitation with ammonium sulphate and DEAE-cellulose ionexchange chromatography. Velocity centrifugation revealed that all of the IgG from intact males was 7S protein while less than 40% of the seminal IgG of vasectomized men cosedimented with the 7S marker; the remaining, immunologically unidentifiable, protein was considerably smaller and heterogeneous in size. Only the 7S IgG from the post-vasectomy ejaculates inhibited the activity of a DNA polymerase from the seminal fluid of an intact male. These results suggest that formation of antibody reactive with the seminal fluid DNA polymerase is one manifestation of a vasectomy-associated autoimmune response in man.

Autoantibodies↗
PubMed1978

In vitro demonstration of Mallory body formation in liver cells from rats fed diethylnitrosamine.

Epithelioid liver cells were established in culture from rats sacrificed 10 to 18 weeks after the administration of the hepatocarcinogen diethylnitrosamine in their drinking water. After approximately 3 months in vitro, more than half the cells propagated from rats that developed hepatocellular carcinomas had bean-shaped, acentrically displaced nuclei with large juxtanuclear homogeneous appearing areas resembling the hyalin or Mallory bodies in the livers of chronic alcoholics. These abnormalities were not seen in the livers of origin, but were retained in the carcinomas that formed after the cultured cells containing such juxtanuclear hyalin inclusions were inoculated into young rats or nude (i.e., thymusless) mice; these features persisted upon reestablishment and continuous passage of the tumor cells in culture. The cells were further characterized by their karyotypes and their growth properties in liquid media and soft agar. By transmission electron microscopy the hyaline bodies in the culture tumor cells were shown to consist of a disorganized meshwork of filaments. Examination by incubating cells with cytochalasin B and by using antiactin and anti-DNase antisera as indirect immunofluorescence probes also revealed a disturbance in the cytoskeleton.

Animals↗
PubMed1978

Inhibition of viral reverse transcriptase and human sperm DNA polymerase by anti-sperm antibodies.

The IgG fraction of serum from a rabbit immunized with detergent-prepared human sperm nuclei inhibited the DNA polymerase activities in human sperm and seminal fluid as well as the partially purified reverse transcriptase of the baboon endogenous type-C retrovirus (BEV). The analogous enzymes from lysates of oncogenic type-C viruses was unaffected. IgG from the serum of individual partners from infertile marriages similarly inhibited both purified BEV reverse transcriptase and human sperm DNA polymerase, but not a DNA polymerase isolated from human prostatic fluid. The data suggest that BEV reverse transcriptase and the human sperm DNA polymerase are antigenically related. Furthermore, the sperm appears to be auto-antigenic and the antibodies thus formed may be capable of interfering with reproductive success.

Antigens↗
PubMed1977

In vivo initiated rat liver carcinogenesis studied in vitro; formation of alcoholic hyaline-type bodies.

Epithelial liver cells isolated from rats after oral diethylnitrosamine administration were established in culture. When propagated in vitro for 2--3 months, over half the cells contained acentric nuclei and large juxtanuclear inclusions resembling the hyaline deposits (Mallory bodies) in cirrhotic livers of alcoholics. The morphological changes and disarrayed filaments in these bodies were retained on serial passages for many months. Cells inoculated into nude mice or newborn rats produced carcinomas from which cells with these abnormalities were reestablished in continuous culture.

Animals↗
PubMed1976

The attachment and penetration of T7 DNA/phage in Syrian hamster embryonic cells.

Bacteriophage T7 DNA can penetrate Syrian hamster embryonic cells after a mandatory initial pretreatment with DEAE-dextran. In 3 h an extracellular complex between T7DNA and the cell monolayer is formed which is equivalent to 105 T7 genomes per cell. During the ensuing 24-48 h of cell growth, an average of 102-103 T7 genomes are transported to the nucleus in 90% of the cells of the culture.

Binding Sites↗
PubMed1975

Ribonuclease-sensitive DNA-synthesizing complex in human sperm heads and seminal fluid.

An endogenous DNA-synthesizing complex sensitive to ribonuclease has been found in purified preparations of swollen human sperm heads. Incorporation of [3H]dTTP into acid-precipitable material occurred in the presence of actinomycin D and required addition of dGTP, dCTP, dATP, plus Mg++. Polymerization was sensitive to pretreatment of the complex with pancreatic RNase A or Triton X-100. Exogenous activity was elicited by the synthetic template (dT)12--18-(rA)n but not by (dT)12--18-(dA)n or (dT)10. The complex sedimented from a 10,000 X g supernatant by centrifugation at 165,000 X g for 60 min and banded in sucrose at a density of 1.21--1.25 g/cm3. Endogenous RNase-sensitive DNA polymerase activity from cell-free seminal fluid was also detected in a fraction in sucrose at a density of 1.22 g/cm3. This activity was labile to freezing and stimulated by 0.04% Triton X-100, and thus differed from that of sperm heads.

Adult↗
PubMed1975

Properties and malignant transformation of established rat liver parenchymal cells in culture.

Epithelioid cells from the livers of normal and genetically impaired (Gunn) rats were established in long-term cultures in vitro. These cells grew as flat, epithelioid cobble-stone-type monolayers and showed a diploid karyotype. They secreted rat serum albumin and proteins into their growth media and contained aryl hydrocarbon hydroxylase. Such cells were transformed by treatment with methylazoxymethanol acetate; they then exhibited an irregular, piling growth pattern, acquired the ability to grow in soft agar, and thereafter grew as tumors in hamsters given cortisone and in nude mice. These malignant spindle-cell tumors were reestablished in culture and still secreted serum albumin. The transformed cells became highly multinucleate when exposed to cytochalasin B and thus behaved like tumor cells. This behavior was not shown by the original cells. Cells transformed by benzo[a]pyrene failed to grow in soft agar culture or as tumor in animals. Cells were not affected by diethylnitrosamine.

Animals↗
PubMed1974

Penetration of somatic mammalian cells by sperm.

Penetration of somatic mammalian cells by spermatozoa occurred after simple admixture in culture. With sperm labeled in vivo, autoradiography revealed incorporation of DNA into nuclei of recipient cells, indicating release of DNA after entrance by sperm. This system provides a new approach to study the molecular biology of information transfer and of haploid gene expression.

Animals↗
PubMed1970

Studies of DNA-induced heritable alteration of mammalian cells.

An intercellular interaction between mouse Ehrlich ascites tumor and non-malignant Chinese hamster cells occurred when these were co-cultured. That the intercellular processes which formed had emanated from the EA cells was revealed by immunofluoroscopy using anti-EA antiserum, and by direct microscopic examination. A passage of DNA from the EA to the CH cells was also observed. On long-term co-culture, new cell forms arose which were isolated, cloned, and propagated. They showed a CH karyotype and had acquired oncogenic potential and the ability to synthesize murine-specific antigens. These same heritable properties were also acquired by CH cells following their exposure to DNA isolated from EA cells.

Animals↗