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M M Sanders

Publications and source records attributed to M M Sanders.

At least 55 records · Page 3Linked to original sources
PubMed1988

Characterization of chloride uptake in Drosophila Kc cells.

Drosophila Kc cells use at least two mechanisms for chloride uptake. These transport systems can be distinguished by their kinetic properties and by their differential sensitivity to various drugs. One transport system predominates at [Cl-]o below 30 mM and is greater than fivefold more sensitive to disulfonic stilbenes than the second system. At [Cl-]o above 30 mM, the predominant uptake mechanism is inhibited by vanadate and nitrate.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1988

ras oncogene is expressed in adenocarcinoma of the endometrium.

Activation of c-ras oncogenes has been implicated in human carcinomas of the colorectum, prostate, bladder and breast. The major peptide product of c-ras is a 21 kilodalton peptide (p21), but other larger "ras-related" peptides have been described in urine obtained from patients with several types of cancers. In the present investigation immunohistochemical methods were used to assess c-ras expression in tissues obtained from patients with endometrial adenocarcinoma. Formalin-fixed, paraffin-embedded tissues were processed in routine fashion, then incubated with a monoclonal antibody raised against a v-H-ras synthetic peptide. ras Peptides were not detected in proliferative or secretory endometrium or in benign adenomatous hyperplasia. One of four specimens of atypical adenomatous hyperplasia and two of 11 specimens of grade 1 (international Federation of Gynecology and Obstetrics) adenocarcinoma stained positive for ras peptides. A total of 95% of the grade 2 and 3 adenocarcinoma studied contained detectable ras peptides within neoplastic cells. In contrast to previous immunohistochemical studies that identified ras peptides only in neoplastic cells of bladder, prostate, colon, and breast cancers, we routinely found ras peptides within stromal cells of high-grade endometrial carcinomas. When stained with hematoxylin and eosin, these cells have the appearance of foamy macrophages.

Adenocarcinoma↗
PubMed1988

CA 125 in tissues and amniotic fluid during pregnancy.

CA 125 was assayed in amniotic fluid and tissue extracts by immunoradiometric assay, and immunohistochemical studies were performed on paraffin-embedded sections of endometrium, decidua, and fetal membranes with the monoclonal antibody OC 125 used as primary antibody. The concentration of CA 125 in amniotic fluid changes during pregnancy so that levels of 800 to 1000 U/ml are found before 12 weeks. Thereafter, levels of 4000 to 10,000 U/ml are detected routinely. As term approaches, amniotic fluid CA 125 concentrations fall to a range of 1000 to 2000 U/ml. Levels of CA 125 in tissue extracts of secretory endometrium and decidua were 65,000 and 29,500 U/gm of tissue, respectively. CA 125 was readily detected on the apical surfaces of glandular epithelium and in the secretions of endometrial glands obtained throughout the menstrual cycle. It was also detected in the lumina of decidualized glands throughout pregnancy. No antigen was detectable within glandular epithelial cells. We have previously reported high concentrations of CA 125 in chorionic tissue extracts (42,000 U/gm) and low concentrations in amniotic tissue extracts (275 U/gm). In contrast to those findings, immunohistochemical techniques detected CA 125 within the intercellular canaliculi that surround amniotic epithelial cells but not in chorion. We conclude that the likely source of amniotic fluid CA 125 is the decidua and that it gains access to the amniotic fluid via the intercellular canalicular system that traverses the amniotic epithelium.

Amniotic Fluid↗
PubMed1988

The MMTV LTR promoter is induced by progesterone and dihydrotestosterone but not by estrogen.

Induction of the mouse mammary tumor virus (MMTV) promoter by steroid hormones was examined in chick oviduct primary cell cultures transfected with MMTV-chloramphenicol acetyl transferase fusion constructs. Our results demonstrate that in this system glucocorticoids, progesterone and dihydrotestosterone are all able to stimulate MMTV transcription; induction by progesterone and dihydrotestosterone is not mediated by glucocorticoid receptors, since the specific glucocorticoid antagonist RU486 did not inhibit the response. In contrast, estrogen does not stimulate MMTV transcription, although estrogen does induce the endogenous ovalbumin gene in the same cells. While progesterone effects are mediated by the same response elements within the MMTV long terminal repeat that were originally characterized for the glucocorticoid receptor, an androgen response element has not yet been defined. Our data indicate that the MMTV long terminal repeat does not contain an estrogen response element.

Animals↗
PubMed1987

Chelating-agent suppression of cadmium-induced hepatotoxicity.

The administration of sodium N-methyl-N-dithiocarboxy-D-glucamine (NaG) at 500 mg/kg, i.p., or sodium calcium diethylenetriaminepentaacetic acid (DTPA) at 632.5 mg/kg, i.p., reduces the serum enzyme levels characteristic of hepatic damage following the intravenous administration of cadmium chloride (3.5 mg CdCl2.2.5H2O/kg). Some effect on serum enzyme levels was found even when the interval between administration of cadmium chloride and that of the antagonist was as great as 4 h. The enzymes examined included aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (SGPT), and alkaline phosphatase (AP). A histopathological examination of the livers of such animals also reveals the presence of a significant protective action.

Alanine Transaminase↗
PubMed1986

Regulation of protein synthesis in heat-shocked Drosophila cells. Soluble factors control translation in vitro.

We have developed an in vitro translation system from heat-shocked and normal Drosophila cultured cells. The lysates retain regulation of translation typical of the whole cells from which they were prepared, both when programmed by endogenous mRNA and when RNA-dependent. These systems have been used to investigate the mechanism of shutdown of normal protein synthesis and selection of heat shock mRNAs for translation in heat shock in Drosophila. Supplementation of intact RNA-dependent lysates with separated ribosome or supernatant fractions from normal or heat-shocked translation systems showed the normal supernatant fraction could "rescue" normal protein synthesis in a heat shock lysate. Normal ribosomes had no rescuing activity and neither heat shock fraction affected translation in normal lysates. Reconstitution of the system from separated ribosomes and supernatant in normal and mixed combinations showed heat shock and normal ribosomes were both competent to support normal protein synthesis with normal supernatant. Heat shock supernatant did not support normal protein synthesis with ribosomes from either source. We conclude that the factors regulating translation in heat-shocked Drosophila cells are soluble factors in the lysate and that the soluble factors present in the normal lysate are dominant.

Animals↗
PubMed1985

Squamous cell carcinoma of the stomach: a study of four patients with comments on histogenesis.

The histogenic origin of squamous carcinoma of the stomach (SCS) is controversial. We report the case of a 55-year-old man who developed SCS following successful chemotherapy for generalized well-differentiated lymphocytic lymphoma. The patient's stomach contained both squamous carcinoma arising in squamous metaplasia and chronic atrophic gastritis with intestinal metaplasia. This case is compared to three additional cases of SCS where no such antecedent mucosal changes were evident. The SCS literature is reviewed and the histogenesis regarding the development of pure squamous tumors of the stomach is discussed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Chicken egg white genes: multihormonal regulation in a primary cell culture system.

A primary cell culture from estrogen-withdrawn chicken oviduct has been developed in which the genes for the major egg white proteins, ovalbumin and conalbumin, are induced by steroid hormones. The responsiveness of the isolated cells depends on the combination of enzymes employed to dissociate the oviduct; trypsin and pronase are essential. Administration of estradiol to cultured cells is insufficient to induce ovalbumin mRNA (mRNAov) to levels achieved in vivo. Both insulin and a second steroid (a glucocorticoid, progestin, or androgen) are required for the induction of the ovalbumin gene by estradiol to the extent reached in vivo. Although low levels of a progestin or androgen can synergize with estradiol to obtain an induction of mRNAov, we have demonstrated that a physiological concentration of corticosterone (10(-8) M) potentiates a large response to estradiol without causing an induction when added alone. When estradiol, corticosterone, and insulin are present in the culture medium, mRNAov increases from about 20 to 6500 molecules/cell by 55 h. With the same culture conditions, conalbumin mRNA increases from about 120 to 4300 molecules/cell by 52 h. After about 55 h, the level of egg white mRNAs decreases, and this reduction in mRNAov correlates with a diminished transcription of that gene. The data obtained with the cultured cells demonstrate that the induction of the ovalbumin gene requires the permissive effects of insulin and a second steroid (probably a glucocorticoid in vivo) to facilitate the response to estradiol.

Animals↗
PubMed1984

Noncoordinate histone synthesis in heat-shocked Drosophila cells is regulated at multiple levels.

Transferring Drosophila tissue culture cells from 25 to 37 degrees C (heat shock) causes histone protein synthesis to become noncoordinate. To determine the level at which this is controlled, the synthesis, degradation, and translation of individual histone mRNAs was studied under both heat shock and control conditions. The increased synthesis of histone H2b protein during heat shock appears to be controlled primarily at the level of translation. During heat shock, H2b mRNA is transcribed at about the same level as in the control. However, H2b mRNA is more stable under heat shock than under control conditions and is predominantly found in polysomes. The reduction in synthesis of H2a, H3, and H4 protein during heat shock appears to be controlled at both the transcriptional and translational levels. Although transcription of H2a, H3, and H4 mRNAs is reduced during heat shock, like H2b mRNA, they are more stable. However, unlike H2b mRNA, these mRNAs are not predominantly associated with polysomes during heat shock. Regulation of H1 synthesis during heat shock is completely different from that of the other histones. During heat shock, H1 mRNA is not transcribed, and unlike all of the other Drosophila mRNAs studied to date, its mRNA is not stable in heat-shocked cells. Results from in vitro translation studies support the conclusion that noncoordinate synthesis of the core histone proteins during heat shock is controlled at the level of translation.

Animals↗
PubMed1983

Characterization of a segmented double-stranded RNA virus in Drosophila Kc cells.

Drosophila Kc cells contain a series of RNA fragments ranging in size from 980 to 4600 bp. The fragments copurify with a virus-like nucleoprotein particle which has a density of 1.384 g/cm3 and is a 62 nm diameter icosahedron. There are 11-13 double stranded RNAs in the particles; they are not homologous with either cultured cell or embryo genomic DNA. The particle also contains a minimum of seven polypeptides, three of which are major, and all of which continue to be synthesized in Kc cells in heat shock when normal cellular protein synthesis is shut down. This virus-like particle occurs in large enough amounts in Kc cells to confuse molecular and physiological studies, however the cells continue to multiply in its presence.

Animals↗
PubMed1983

Dephosphorylation of S6 and expression of the heat shock response in Drosophila melanogaster.

A basic ribosomal phosphoprotein of 30,000 molecular weight was rapidly dephosphorylated in cultured Drosophila melanogaster cells heat shocked at 37 degrees C. The protein was associated with the 40S ribosomal subunit and had an electrophoretic mobility similar to that of purified rat liver protein S6 on basic two-dimensional polyacrylamide gels as well as a similar partial proteolysis peptide map. In logarithmically growing cultures, this D. melanogaster S6 protein appeared to have a single phosphorylated species consisting of 30 to 40% of the total cellular S6. Thus, the nearly complete dephosphorylation of this protein observed in heat shock involves a large fraction of the cellular S6. The significance of this dephosphorylation in the expression of the heat shock response was investigated by examining the phosphorylation status of S6 in recovery from heat shock and in response to chemical inducers of the heat shock response. During recovery from a 30-min heat shock, the recovery of normal protein synthesis was almost complete in 2 to 4 hr, whereas there was no significant rephosphorylation of S6 for 8 h. Two chemical inducers of the heat shock response, canavanine and sodium arsenite, induced the synthesis of heat shock proteins in D. melanogaster cells. Sodium arsenite also caused an inhibition of normal protein synthesis similar to that observed in heat shock. Neither agent, however, caused significant dephosphorylation of S6. These results suggest that the dephosphorylation of S6, although invariably observed in heat-shocked cells, may in some cases be dissociated from both the induction of heat shock protein synthesis and the turnoff of normal protein synthesis which occur in a heat shock response.

Animals↗
PubMed1981

Esophageal intramural pseudodiverticulosis.

Esophageal intramural pseudodiverticulosis (EIP) is a rare condition of unknown etiology. It is characterized by multiple, small, flaskshaped outpouchings in the esophageal wall. Involvement may be segmental or diffuse. Since this entity was first reported in 1960, there have been 43 cases described in the English literature. These cases are reviewed and six additional cases are reported with emphasis on clinical and radiographic parameters of this entity.

Adult↗
PubMed1981

Vimentin: a phosphoprotein under hormonal regulation.

Past studies of norepinephrine-stimulated protein phosphorylation in intact C-6 glioma cells had identified a 58,000 molecular weight, 5.7 isoelectric point protein (58K-5.7) as a cyclic AMP-dependent phosphoprotein and had shown that 58K-5.7 was one of the most abundant proteins of the nuclear fraction. Initial experiments of present studies showed that the 58K-5.7 protein remained with the nuclear ghost, or matrix structure, after removal of chromatin. Based on the size, acidity, abundance, nonsolubilization by nonionic detergent and salt, and solubilization by urea, the hypothesis was advanced that the 58K-5.7 protein was the vimentin-type intermediate filament protein. The hypothesis was tested by two types of immunochemical experiments. Antisera against hamster vimentin reacted selectively with only the 58K-5.7 protein in polyacrylamide gels of urea-solubilized cellular residues (i.e., nonionic detergent and 0.6 M salt-insoluble material) as determined by immunoautoradiography. Antisera against the pure 58K-5.7 protein of C-6 cells bound selectively to a fibrous array of cellular material typical of vimentin filaments as determined by indirect immunofluorescence. It is concluded that the 58K-5.7 protein is vimentin.

Animals↗
PubMed1981

Identification of histone H2b as a heat-shock protein in Drosophila.

Total cell polypeptides synthesized, in cultured Drosophila cells under control (25 degrees C) and heat-shock (37 degrees C) conditions have been compared in two different two-dimensional polyacrylamide gel electrophoresis systems which, together, resolve polypeptides having a wide range of isoelectric points, including the most basic polypeptides of the cell. The electrophoresis of basic proteins showed that the most prominent basic polypeptide synthesized in heat shock comigrated with histone H2b. This heat-shock polypeptide was identified as histone H2b by two criteria: (a) it comigrated with authentic histone H2b in Triton-urea-acetic acid acrylamide gel electrophoresis after solubilization from nuclei with acid; and (b) partial proteolysis peptide maps of the basic heat-shock protein and histone H2b were identical. The synthesis of histone H2b was induced threefold in heat shock, whereas synthesis of the other histones was reduced from two- to tenfold. The noncoordinate synthesis of histones in Drosophila in heat shock provides an interesting system in which to investigate transcriptional and translational controls of histone synthesis as well as assembly of histones into chromatin.

Animals↗