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D M Gersten

Publications and source records attributed to D M Gersten.

At least 55 records · Page 3Linked to original sources
PubMed1983

Computer applications in analysis, mapping and cataloging of proteins separated by two dimensional electrophoresis.

Two dimensional electrophoretic separation of complex mixtures of proteins can only be exploited to its fullest potential using sophisticated computerized spot detection, quantification, pattern recognition, pattern normalization, data reduction and data storage. We present a discussion of some of the technical problems and of the options available which will ultimately lead toward full computerization of the data.

Computers↗
PubMed1982

Recurrent decreases of erythrocyte electrophoretic mobility in rats exposed to 1.0 R whole-body x-radiation.

Circulating erythrocytes from rats were examined up to 30 weeks post whole-body exposures of 1.0 R for alterations in the expression of net negative surface charge as measured by whole-cell microelectrophoresis in saline sorbitol. Erythrocyte electrophoretic mobility was determined in an apparatus composed of a horizontal transilluminated cylindrical chamber, equipped with a reversible, blacked platinum electrode, immersed in a water bath maintained at 25.0 +/- 1.0 degree C (Rank Brothers). In two separate experiments, recurrent decreases in the expression of net negative surface charge occurred at 10, 17, and 30 weeks post-irradiation. At these times distributional analyses of recorded erythrocyte electrophoretic mobility (EEPM) values revealed a skewing of the normally distributed EEPM population values to lower EEPM. Total sialic acid content released from hydrolyzed erythrocyte membrane preparations revealed no significant differences between erythrocytes from sham and irradiated animals. In vivo post-irradiation labeling of erythrocytes with diisopropyl-[32P] phosphorofluoridate at 4 and 33 weeks (separate experiments) indicated only a minor abbreviated erythrocyte life span at 33 weeks. Therefore, effects from low dose (1.0 R) whole-body irradiation would appear to include a recurrent defect in the expression of the net negative surface charge.

Animals↗
PubMed1981

Characterization of immunologically significant unique B16 melanoma proteins produced in vivo and in vitro.

Proteins unique to B16 melanoma cells grown in culture and as solid tumors have been independently described recently. As both proteins have apparent M(r) of 65,000-70,000, we have more fully compared their biochemical characteristics. The M(r) 65,000 protein, which is isolated from B16 cells in culture, has an aggregate molecular weight of >200,000 under nonreducing conditions. This M(r) 65,000 form is shed into the culture medium exclusively and is the predominant molecular species of serum-free culture supernatants. It was found that B700, a major membrane protein of B16 cells in solid tumors, and the M(r) 65,000 preparation from cultured cells were electrophoretically identical when compared under four separate sets of conditions. These two proteins also share immunologic determinants. The results suggest the identity of these two proteins isolated by completely different approaches.

Animals↗
PubMed1980

Albumin obscures sex differences in blood protein patterns of rats and humans.

Sex related differences in the blood protein patterns of male and female rats and humans have been studied by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. In rats, a prominent band of mol.wt. 74000--78000 is seen in females in far greater quantity than in males, castrated males or ovariectomized females. A secondary band of 100000 is seen under non-reducing conditions in female rats that is absent in males. In humans, bands of 92000 and 88000 mol.wt. appear to be variable in concentration in men although relatively constant in women. The above differences are observable only if serum albumin is removed from the samples before electrophoresis. The results suggest that each sex has its own characteristic blood protein pattern.

Adolescent↗
PubMed1980

Control of growth and vascularity of B16 melanoma by syngeneic lymphocytes.

We have studied the participation of syngeneic lymphocytes in the subcutaneous growth and vascularization of B16 melanoma tumors. Subcutaneous tumors in animals, lymphocyte depleted by thymectomy and x-irradiation, exhibit slow, poorly vascularized growth as compared to normal or lymphocyte reconstituted controls. This condition may be reversed by administration of lymphocytes to lymphocyte deficient hosts either prior to tumor cell injection or while the animal is tumor bearing. The results are discussed in terms of lymphocyte induced angiogenesis.

Animals↗
PubMed1979

Influence of immune status on the metastasis of three murine fibrosarcomas of different immunogenicities.

Three fibrosarcomas of different immunogenicities were tested for their ability to form spontaneous and experimentally induced metastases in normal, sham-suppressed, immunosuppressed, and immunologically restored syngeneic mice. Immunosuppression, achieved by adult thymectomy and sublethal X-irradiation (450 R), affected experimental metastasis of the three tumors in different ways. Upon i.v. injection, the highly immunogenic fibrosarcoma formed more pulmonary tumor colonies in immunosuppressed mice than in normal, sham-suppressed (sham thymectomy and 450 R), or immunologically reconstituted animals (thymectomy, X-irradiation, plus 10(7) normal syngeneic lymphocytes given i.v.). A fibrosarcoma of intermediate immunogenicity also formed more pulmonary metastases in immunosuppressed recipients, but this increase could not be reversed by reconstitution with 10(7) lymphocytes. In contrast, the least immunogenic tumor formed fewer pulmonary tumor colonies in immunosuppressed mice than in normal, sham-suppressed, or immunologically reconstituted mice. We conclude that the role of the immune system in experimental cancer metastasis varies for different tumors and that tumor immunogenicity is an important factor in the relationship between host immunity and tumor dissemination.

Animals↗
PubMed1978

A rapid, novel method for the solid-phase derivatization of IgG antibodies for immune-affinity chromatography.

We show that a solid-phase immune adsorbent can be prepared from rabbit antiserum by isolating the IgG fraction with the A protein of Staphylococcus aureus associated covalently with a Sepharose matrix. The IgG is then coupled to the matrix using the cross-linking agent dimethylsuberimidate. IgG antibody bound in this fashion is in the proper orientation for combination with antigen because association with protein A occurs via the Fc portion of the IgG molecule, thus leaving the combining site of the molecule free to interact with antigen.

Antibodies, Anti-Idiotypic↗
PubMed1978

Radioprotection in E. coli by an agent from M. radiodurans.

An agent extracted from the radioresistant bacterium M. radiodurans was found to protect several strains of E. coli from X-radiation. Optimal radioprotection was observed when the repair-proficient B/r strain was irradiated in the presence of the agent under hypoxic conditions. It is proposed that this agent acts to modify damage incurred in the presence of reduced oxygen concentrations so that this damage might be subsequently repaired.

Escherichia coli↗
PubMed1977

Relationship of host immune status to tumor cell arrest, distribution, and survival in experimental metastasis.

The kinetics of initial arrest in organs, distribution, survival, and fate of 125I-iododeoxyuridine-labeled B16 melanoma tumor cells injected intravenously into normal, tumor-sensitized and immune manipulated syngeneic and allogeneic mice were investigated. Groups of animals were killed at intervals ranging from two minutes to 14 days after intravenous tumor cell injection. Lungs, liver, spleen and blood were collected from each animal and processed so that radioactivity associated with DNA of tumor cells viable at the time of sacrifice could be monitored. The following conclusions can be made: initial tumor cell arrest in organs is influenced by the host immune status but it does not correlate with the survival kinetics or development into tumors. The same tumor, which was rejected in mice after a subcutaneous tumor challenge, grew in the lungs after intravenous injection. Therefore, rejection of a subcutaneous challenge as the sole criterion of host immunity to neoplasms should be questioned. Allogeneic animals are not appropriate for use as a model system for the study of experimental metastasis. Animals sensitized to a tumor exhibit kinetic patterns of tumor cell arrest and survival that differ from normal syngeneic hosts.

Animals↗