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Biomedical subjects

S Pathak

Publications and source records attributed to S Pathak.

At least 145 records · Page 8Linked to original sources
PubMed1986

Leukocyte migration inhibitory factor (LIF) to sperm from autoimmune men in infertile couples.

Leukocyte migration inhibitory factor (LIF) is produced by lymphocytes with receptors specific to sensitizing antigens. This principle was used to detect possible antigenic differences between sperm of autoimmune and nonautoimmune men. Sixteen fertile and 91 infertile couples were screened for cytotoxic and hemagglutinating antibodies to sperm from their husbands and controls. Their lymphocytes were tested for the production of LIF to sperm extracts and seminal plasma from the husbands and controls by a direct leukocyte migration inhibition assay. Twenty-nine of 35 men producing LIF to sperm and/or seminal plasma were positive for sperm antibodies (p = 0.0004, vs sperm antibody-negative controls). Twenty-three of 29 wives with LIF production had sperm-autoimmune husbands (p = 0.04). Leukocyte migration was significantly inhibited in sperm-autoimmune men by autologous sperm extracts and seminal plasma in contrast to control sperm extracts and seminal plasma (p = 0.0006 and 0.001, respectively). The wives of autoimmune men had significantly higher LIF responses to their husbands' sperm extracts than to other antigens (p = 0.02). Men with cytotoxic antibodies in their seminal plasma produced LIF to autologous sperm (p = 0.001). It is suggested that certain sperm and seminal plasma antigens of autoimmune men may lead to specific humoral and cell-mediated immune responses in both partners.

Antilymphocyte Serum↗
PubMed1986

Specific chromosome anomalies and predisposition to human breast, renal cell, and colorectal carcinoma.

Specific chromosome abnormalities in three human solid tumors of adulthood--renal cell carcinoma, breast tumor, and colon carcinoma--are described. Two of the neoplasms are associated with a reciprocal translocation involving chromosome #3 (breakpoint at band p13-14 with 6, 8, 11, and 16) in renal cell carcinomas and chromosome #1 (breakpoint at band q21 with chromosomes #3, #5, #10, #11, and #12) in breast carcinomas. Most of these chromosomal rearrangements have been seen as tumor-specific acquired changes in tumor cells, as well as some constitutionally present in normal tissues of patients. In a limited number of colorectal carcinoma samples a deletion in the short arm of a chromosome #12 is implicated as a specific abnormality. The expression of fragile sites in these specific chromosomal regions in the normal peripheral blood cultures might identify an individual predisposed to develop a particular type of neoplasm.

Breast Neoplasms↗
PubMed1986

Methodologic advances in the cytogenetic analysis of human solid tumors.

The major obstacle to successful cytogenetic analysis of human solid tumors is the acquisition of sufficient numbers of good quality metaphases for detailed cytogenetic analysis. At present, no single methodologic approach has been proven to provide successful chromosomal analysis of all human solid tumors. The technical aspects of cell culture, chromosome harvesting, and chromosome banding were the focus of considerable discussion during the First Workshop on Chromosomes in Solid Tumors. This report provides summaries of several technical protocols, emanating from several different laboratories, which have contributed to successful chromosome analysis of a variety of human solid tumors.

Cell Separation↗
PubMed1986

Monoclonal antibodies to human osteosarcoma-associated antigen(s).

Monoclonal antibodies (MoAbs) against human osteosarcoma cells were obtained by the production and cloning of hybrids resulting from the fusion of mouse myeloma cells P3 X 63Ag8.653 with spleen cells from partially purified, osteosarcoma-associated antigen (OSAA)-immunized BALB/c mice. OSAAs were isolated from the spent culture medium of a human osteosarcoma cell line (TE-85). Five hybrid clones were established and designated as OSA1, OSA2, OSA3, OSA4, and OSA5. OSA1 and OSA2 had similar activity. All 5 MoAbs reacted strongly with most osteosarcoma cell lines and with all osteosarcoma tissues tested but not with 10 tumor cell lines and 2 tumor tissues from other cancers. OSA3, OSA4, and OSA5 cross-reacted with a fibrosarcoma cell line, a colon cell line, and fibrosarcoma, respectively, as well as with a melanoma cell line. None of the MoAbs were reactive with activated normal human peripheral blood mononuclear cells (PBMC). Immunoprecipitation of membrane protein isolated from LM cells and TE-85 cells with the MoAbs OSA1 and OSA2 conjugated with Staphylococcus aureus yielded a molecule with molecular weight of approximately 92,000. No detectable membrane protein was precipitated when 125I-labeled membrane protein from pooled activated human PBMC and tumor cells of other histologic types were used in the immunoprecipitation.

Animals↗
PubMed1986

Drug and radiation sensitivity measurements of successful primary monolayer culturing of human tumor cells using cell-adhesive matrix and supplemented medium.

The limitations of the agar suspension culture method for primary culturing of human tumor cells prompted development of a monolayer system optimized for cell adhesion and growth. This method grew 83% of fresh human tumor cell biopsy specimens, cultured and not contaminated, from a heterogeneous group of 396 tumors including lung cancer (93 of 114, 82%); melanoma (54 of 72, 75%); sarcoma (46 of 59, 78%); breast cancer (35 of 39, 90%); ovarian cancer (16 of 21, 76%); and a miscellaneous group consisting of gastrointestinal, genitourinary, mesothelioma, and unknown primaries (78 of 91, 86%). Cell growth was characterized morphologically with Papanicolaoustained coverslip cultures and cytogenetically with Giemsastained metaphase spreads. Morphological features such as nuclear pleomorphism, chromatin condensation, basophilic cytoplasm, and melanin pigmentation were routinely seen. Aneuploid metaphases were seen in 90% of evaluable cultures, with 15 of 28 showing 70% or more aneuploid metaphases. Colony-forming efficiency ranged between 0.01 and 1% of viable tumor cells, with a median efficiency of 0.2%. This culture system uses a low inoculum of 25,000 viable cells per well which permitted chemosensitivity testing of nine drugs at four doses in duplicate from 2.2 X 10(6) viable tumor cells and radiation sensitivity testing at five doses in quadruplicate from 0.6 X 10(6) cells. Cultures were analyzed for survival by computerized image analysis of crystal violet-stained cells. Drug sensitivity studies showed variability in sensitivity and in survival curve shape with exponential cell killing for cisplatin, Adriamycin, and etoposide, and shouldered survival curves for 5-fluorouracil frequently seen. Radiation sensitivity studies also showed variability in both sensitivity and survival curve shape. Many cultures showed exponential cell killing, although others had shouldered survival curves. This method for growing cells from primary human biopsy specimens is more efficient than the agar culture method, enables easier and better biological analysis of the actual cells grown, and permits improved characterization of drug and radiation survival curves.

Biopsy↗
PubMed1985

Ag-NOR staining in human chromosomes: differential staining in normal and leukemic bone-marrow samples.

A silver staining technique developed by Goodpasture and Bloom (1975) stains a specific protein associated with the activity of ribosomal cistrons during the preceding interphase. By counting the number of chromosomes with darkly stained nucleolus organizer regions (NORs), the number of active NORs per metaphase can be determined. A comparison of NOR activity in bone-marrow cells from leukemic patients in different stages of disease with that of bone marrow from normal, healthy individuals was conducted and differential NOR activity was detected. The control group showed significantly lower NOR activity when compared with a group of patients with acute lymphocytic leukemia (ALL). These preliminary data indicate that this simple cytochemical technique can be effectively used to differentiate between normal and ALL bone-marrow samples.

Bone Marrow↗
PubMed1985

Establishment of stable human T-T hybridomas.

Human T-T hybridomas potentially provide an invaluable resource for a variety of immunoregulatory molecules that modulate the immune response. To date, success in this technology, using human cell populations, has been hampered by several problems associated with proliferative and functional instability of the hybrid cells. These forms of instability are the result of a multifactorial process, with 1 parameter of importance being the chromosome number of the malignant parent cell line used for fusion. The present studies describe the production of a stable human T-T hybridoma generated by fusing a near diploid (modal chromosome number of 48) aminopterin-sensitive T cell line, CEM TG E11, and lectin-stimulated human peripheral blood lymphocytes. The rapidly growing hybrid cells have been clonally selected for the production of a B cell growth factor. Hybridization was documented by the presence of HLA phenotypes reflecting the combined antigens of the fusion partners. Fusions with 4 other partners besides CEM TG E11, where the majority of the cells had modal chromosome numbers ranging from 78 to 94, were proliferatively unstable. To date, hybrid cells derived from the CEM TG E11 fusion have been doubling approximately every 48 h for greater than 12 months, and selected clones constitutively produce B cell growth factor.

B-Lymphocytes↗
PubMed1985

Double minutes in the HeLa cell line.

Metaphase preparations of three sublines of the HeLa line showed the presence of double minutes (DM) in varying frequencies. In two sublines (S3 and TCH-3753), the size of the DM was variable, whereas in the Fe-1000 subline, they were uniform. Giemsa banding preparations revealed typical HeLa marker chromosomes in all sublines.

Cell Line↗
PubMed1985

Anti-kinetochore antibodies: use as probes for inactive centromeres.

Application of a modified immunofluorescence technique using an anti-kinetochore serum enables cytogeneticists to obtain quality metaphase spreads and to localize kinetochores. In a patient with a 45, XX, -9, -11, tdic (9p;11p) constitution, we found that the dicentric marker chromosome has an intensely fluorescent kinetochore (no. 11), the functional centromere, and a less intensely fluorescent kinetochore (no. 9), the inactive centromere. The data suggest that in the process of tandem fusion (telomere-telomere between 11p and 9p), the centromere of chromosome 9 was not deleted, but, rather, inactivated.

Antibodies↗
PubMed1984

Presence of retrovirus in the B95-8 Epstein-Barr virus-producing cell line from different sources.

The B95-8 cell line, a widely used source of highly transforming Epstein-Barr virus (EBV), obtained from the laboratory of origin, harbored an infectious retrovirus. This retrovirus generally resembled the Type D retroviruses structurally and developmentally and like the Type D retroviruses preferred Mg2+ to Mn2+ in its RNA-directed DNA polymerase reaction. Evidence for the presence of retrovirus was found in B95-8 cultures from two other sources within the United States, either by assay for polymerase or by electron microscopy. Comparison of two B95-8 cell lines showed cytogenetic differences as well as differences in retroviral activities. The results suggest that any B95-8 culture should be tested for the presence of retrovirus before its use as a source of EBV.

Animals↗
PubMed1984

Two adult siblings with thrombocytopenia and a familial 13;14 translocation.

A woman with thrombocytopenia that progressed to aplastic anemia, and her brother, who had persistent thrombocytopenia, both had a constitutional t(13;14) translocation. Six other family members, in three generations, had the same translocation, but no hematologic disorder. There was evidence suggestive of increased chromosomal fragility in lymphocyte cultures from two members of the kindred, but not in the two patients. The findings support a postulated association between the t(13;14) and hematologic disorders, but whether the mechanism involves an inherited defect in chromosomal stability is unproved.

Chromosome Fragility↗
PubMed1983

Reduced NOR association frequency in a 13/18 translocation chromosome. A family study.

The association frequency of a functional, intercalary NOR in fibroblasts of five carriers of a translocation t(13;18) was significantly lower than the average association frequency of normal G- and D-group chromosomes in the same carriers. This decreased coefficient of association does not seem to be attributable to partial loss of the NOR during rearrangement or to a loss of NOR activity, as indicated by silver staining. It is hypothesized that either (1) interphase associations including this chromosome form less frequently or, more likely, (2) associations with this chromosome are differentially susceptible to physical disruption due to flattening of association complexes during cell preparation. The presence of this abnormal NOR chromosome did not affect the association behavior of normal G- and D-group chromosomes in carrier cells. In addition, the present study supports previous observations that G-group chromosomes associate with a greater average frequency than D-group chromosomes.

Chromosome Mapping↗
PubMed1983

A retrovirus-producing transformed mouse cell line derived from a human breast adenocarcinoma transplanted in a nude mouse.

A transplantable tumor was established in NIH/Swiss/Nu mice from tissue derived from a human breast adenocarcinoma metastatic to the brain. Cultivation of dispersed cells from the third transplant generation of the tumor produced a rapidly growing, high-density culture of fibroblastlike cells. Chromosome and isozyme assays showed these cells to be of mouse origin. The cells behaved as an established line from initial culture. Cells of the tissue culture line, designated NM-1, produced rapidly growing fibrohistiocytomas in nude mice. Electron microscopy revealed that the cells produced large numbers of type C virus particles. Serological, biochemical, and infectivity assays indicated that the retrovirus produced by NM-1 cells is an ecotropic, infective, murine retrovirus antigenically related to, but distinguishable from, Gross and Moloney viruses. The virus did not transform mouse fibroblasts. The data support the conclusion that mouse stromal cells within the transplanted human tumor had undergone malignant transformation and induction to virus replication. The role of the virus in the malignant transformation remains to be clarified.

Adenocarcinoma↗
PubMed1983

Differential NOR activities in somatic and germ cells of Monodelphis domestica (Marsupialia, Mammalia).

Somatic and germ cells of the gray short-tailed opossum (Monodelphis domestica) were analyzed cytogenetically by C-banding, G-banding, and silver staining. The diploid chromosome number was found to be 18. C-banding revealed constitutive heterochromatin at the centromeres of all chromosomes, with additional heterochromatin on one arm of the Y. Silver staining for the localization of nucleolus organizer regions (NORs) showed NORs on the X and on a pair of autosomes, tentatively designated as chromosome 5. In females, the NORs on both X chromosomes were active in 98.3% of all somatic cells analyzed, indicating that this locus escapes sex-chromosome dosage compensation. Chromosome 5 showed an active NOR in only 16.2% of cells scored from the six females. In males, 100% of the somatic cells analyzed showed an active NOR on the X chromosome. Greater variability of autosomal NOR activity was observed between male individuals and between different tissue of the same male. Silver staining of pachytene spermatocytes revealed that (1) only an autosomal NOR was active, whereas the NOR of the X chromosome was inactive, and (2) the X and Y chromosomes showed asynaptic behavior, even though all autosomal synaptonemal complexes were fully formed during this stage.

Animals↗