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D M Gersten

Publications and source records attributed to D M Gersten.

67 records · Page 4Linked to original sources
PubMed1977

Quantitative analysis of macrophage phagocytosis by uptake of particulate 192iridium.

This study describes a method for the quantitation of macrophage phagocytosis by measuring the uptake of small particles of the radioactive inert metal, iridium (192Ir). It is shown that macrophage labeling with 192Ir was uniform, and the label was retained by the macrophages up to 21 days post-plating (when all cultures were terminated). 192Ir labeled macrophages were able to phagocytose other particles such as sheep red blood cells and were able to be activated to become tumorcidal in vitro 21 days following initial 192Ir uptake. Therefore, 192Ir could be a useful tool for the quantitative analysis and correlation of phagocytosis, tumor cytotoxicity and other macrophage functions.

Animals↗
PubMed1976

Erythrocyte surface membrane alterations.

Electrophoretic mobility measurements were made of red blood cells obtained from patients with Duchenne and myotonic muscular dystrophy, from dystrophic mice and chickens, and from corresponding controls. Alterations in the erythrocyte surface electrokinetic properties were found in dystrophic mice and chickens and in many, but not all, patients with muscular dystrophy. The results are consistent with the concept of muscular dystrophy as a systemic membrane disease not limited to muscle.

Adolescent↗
PubMed1976

Characterization in vivo and in vitro of tumor cells selected for resistance to syngeneic lymphocyte-mediated cytotoxicity.

This report describes the selection and behavior of tumor cells resistant to cytolysis by syngeneic lymphocytes. Two B16 melanoma lines, F1 (low metastasis) and F10 (high metastasis), were cultured with lymphocytes from C57BL/6 mice immunized against B16. The selection procedure involved repeated exposure of the tumor cells to lymphocytes in vitro. After each interaction, the viable tumor cells were trpsinized, replated, and designated lines F1Lr-1 and F10Lr-1. The procedure was repeated five times, yielding lines F1Lr-6 and F10Lr-6, which resisted cytolysis by syngeneic lymphocytes. Mice were given s.c. or i.v. injections of cells from lines F1, F1Lr-6, F10, or F10Lr-6. Tumor growth patterns were the same for all four lines when the cells were injected s.c., however, the incidence of pulmonary metastases differed significantly after i.v. injection. Line F10 cells yielded more pulmonary metastases than an equal number of line F1 cells (p less than 0.01). F1Lr-6 cells yielded significantly fewer metastases than an equal number of lines F1 cells (p less than 0.01). A similar difference between F10Lr-6 and F10 cells was observed. The incidence of artificial metastases after i.v. injection of F10Lr-6 cells was similar to that for F1 cells. The quantitative organ distribution, arrest, and survival of i.v.-injected tumor cells were studied by using [125]-5-iodo-2'-deoxyuridinelabeled cells. There was a significantly greater number of cells from line F10, arrested and able to survive for 14 days in lungs, than cells from line F1. In contrast, cells from either line F1Lr-6 or F10Lr-6 had a lower incidence of arrest and survival than their lymphocyte-sensitive counterparts.

Animals↗
PubMed1974

The lysosome periphery: biochemical and electrokinetic properties of the tritosome surface.

Normal rat liver lysosomes were isolated by the technique of loading with Triton WR-1339. Purity of the preparation was monitored with marker enzymes; a high enrichment in acid hydrolases was obtained in the tritosome fraction. In 0.0145 M NaCl, 4.5% sorbitol, 0.6 mM NaHCO(3), pH 7.2 at 25 degrees C the tritosomes had an electrophoretic mobility of -1.77 +/- 0.02 microm/s/V/cm, a zeta potential of 23.2 mV, a surface charge of 1970 esu/cm(2), and 33,000 electrons per particle surface assuming a tritosome diameter of 5 x 10(-7) m. Treatment of the tritosomes with 50 microg neuraminidase/mg tritosome protein lowered the electrophoretic mobility of the tritosome to -1.23 +/- 0.02 microm/s/V/cm under the same conditions and caused the release of 2.01 microg sialic acid/mg tritosome protein. Treatment of the tritosomes with hyaluronidase did not affect their electrophoretic mobility, while trypsin treatment elevated the net negative electrophoretic mobility of the tritosomes. Tritosome electrophoretic mobilities indicated a homogeneous tritosome population and varied greatly with ionic strength of the suspending media. pH vs. electrophoretic mobility curves indicated the tritosome periphery to contain an acid-dissociable group which likely represents the carboxyl group of N-acetylneuraminic acid; this was not conclusively proven, however, since the tritosomes lysed below a pH of 4 in the present system. Total tritosome carbohydrate (anthrone-positive material as glucose equivalents) was 0.19 mg/mg tritosome protein while total sialic acid was 3.8 microg (11.4 nmol)/mg tritosome protein. A tritosome "membrane" fraction was prepared by osmotic shock, homogenization, and sedimentation. Approximately 25% of the total tritosome protein was present in this fraction. Analysis by gas-liquid chromatography and amino acid analyzer showed the following carbohydrate composition of the tritosome membrane fraction (in microgram per milligram tritosome membrane protein): N-acetylneuraminic acid, 14.8 +/- 3; glucosamine, 24 +/- 3; galactosamine, 10 +/- 2; glucose, 21 +/- 2; galactose, 26 +/- 2; mannose, 31 +/- 5; fucose, 7 +/- 1; xylose, 0; and arabinose, 0. The results indicate that the tritosome periphery is characterized by external terminal sialic acid residues and an extensive complement of glycoconjugates. Essentially all the tritosome N-acetylneuraminic acid is located in the membrane and about 53% of it is neuraminidase susceptible.

Animals↗
PubMedDate not supplied

The use of radioactive bacteriophage proteins as X-Y markers for silver stained two-dimensional electrophoresis gels and quantification of the patterns.

We have demonstrated the feasibility of using bacteriophage ghost proteins, tritiated by metabolic labeling, as a set of standard markers for two-dimensional gels in which the proteins are to be detected by silver staining. The results indicate that a 2.5 microgram load of phage proteins yields a reproducible silver pattern of 48 spots. The spots can also be readily identified by radioautography and radiofluorography, establishing their value as a standard constellation of markers. Quantification of these patterns by computerized densitometry indicates a general agreement between detection by silver staining and detection by radiofluorography.

Biomarkers↗
PubMedDate not supplied

Comparison of 5'-nucleotidase activities among cultured murine melanoma cell lines.

The activity of 5'-nucleotidase and ouabain-sensitive Na/K ATPase was determined in seven different mouse melanoma cell lines. Ouabain-sensitive Na/K ATPase activity was found in NP40-treated cell homogenates of all cell lines. However, 5'-nucleotidase activity was found in only one mouse melanoma cell line--JB/RH. The absence of expression of 5'-nucleotidase activity in the other six cell lines is not associated with pigmentation in melanoma cells, nor is the gene switched off in all transformed melanocytes of C57BL/6 origin.

5'-Nucleotidase↗
PubMedDate not supplied

Malignant melanoma: relationship to parameters of differentiation.

Malignant melanoma is not only one of the most aggressive and lethal types of neoplasm, but its incidence in the general population is currently increasing at an alarming pace. It is interesting that most melanomas retain many of their characteristics of differentiation, including a dendritic nature and the production of melanin. This review discusses the phenotypic properties of melanoma cells, including their state of differentiation, and their tumourigenic and metastatic potentials, and attempts to provide an overview of the state of current research on the interrelationships between those parameters in murine and human systems.

Animals↗