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A Deisseroth

Publications and source records attributed to A Deisseroth.

At least 73 records · Page 4Linked to original sources
PubMed1985

Regulatory factors specific for adult and embryonic globin genes may govern their expression in erythroleukemia cells.

In order to test if trans-acting regulatory factors specific for globin genes of the adult and embryonic stages of development exist in erythroid cells, transcriptionally active embryonic and adult globin genes on the same chromosome were transferred by cell fusion from the human leukemia cell K562 into phenotypically adult mouse erythroleukemia cells. Restriction-fragment-length polymorphisms of the K562 zeta (embryonic) globin genes were used to establish that all three copies of human chromosome 16 present in the K562 cell showed the same pattern of human globin gene expression after transfer to the mouse erythroleukemia cell. Adult (alpha) but not embryonic (zeta) human globin mRNA was detected in all nine of the independently derived mouse erythroleukemia hybrid cells, each of which contained human chromosome 16. Restriction endonuclease studies of the K562 alpha- and zeta-globin genes after transfer into the mouse erythroleukemia cell showed no evidence of rearrangements or deletions that could explain this loss of zeta-globin gene expression. These data suggest that regulation of globin gene expression in these erythroleukemia cells involves trans-acting regulatory factors specific for the adult and embryonic stages of development.

Animals↗
PubMed1982

Regression of canine mammary carcinoma after immunoadsorption therapy.

The plasma of dogs afflicted with mammary carcinoma was perfused through chambers bearing Staphylococcus aureus Cowan strain I in an attempt to remove tumor-promoting, immunosuppressive immune complexes from the peripheral blood of these animals. In this canine model of spontaneous mammary carcinoma, reduction of breast and/or soft-tissue tumor (posttreatment size equal to 0 to 50% of pretreatment tumor size) was observed in five of the ten animals so treated. Immune complexes capable of blocking lymphocytotoxicity were measured pre- and postimmunoadsorption; removal was more efficient in the five responders (four of six complexes) than in nonresponders (one of ten complexes), although statistical significance was not attained. The reduction of tumor size seen in soft-tissue sites was not always accompanied by a similar reduction of tumor size in visceral sites, and surgical resection of residual soft-tissue tumor nodules remaining after immunoadsorption treatment was required to achieve a complete response in two responding animals. No significant decrease in tumor size was observed in the control group, perfused without immunoadsorbent, nor in five additional tumor-bearing animals infused with normal dog plasma which had been passed through S. aureus Cowan strain I-containing chambers. These data indicate that immunoadsorption of tumor-bearing host plasma can result in reduction in size of canine mammary adenocarcinoma but that the response is dependent on the site of the tumor (s.c. versus visceral) and may require utilization of other modalities to achieve a complete disappearance of the tumor.

Adenocarcinoma↗
PubMed1982

Phase I trial of Staphylococcus aureus Cowan I immunoperfusion.

Staphylococcus aureus Cowan I has shown antitumor activity in in vitro and in animal tumor models. It is hypothesized that this antineoplastic effect results from the interaction of protein A on the cell surface of Cowan I strain S. aureus and immunosuppressive circulating immune complexes. Therefore, we treated five patients with ex vivo plasma immuno-perfusion over killed and fixed S. aureus Cowan I. Toxic effects were marked in all patients and appeared to be related to the plasma volume infused and rate of infusion. Toxic reactions occurred in the cardiovascular, respiratory, and hematopoietic systems. No responses even minimal or transient, were observed in this phase I trial. This toxicity may be reduced if the rate of plasma infusion decreases.

Adult↗
PubMed1981

Expression of human and mouse nonhistone chromosomal proteins in hybrid mouse erythroleukemia cells containing a single human chromosome.

The nonhistone chromosomal proteins of a series of hybrid mouse erythroleukemia cell lines containing human chromosome 16 were investigated by two-dimensional gel electrophoresis to determine if such cells contained nonhistone chromosomal proteins of both human and mouse origin. Comparison of the two-dimensional gel electrophoretograms of the nonhistone chromosomal proteins of mouse and human cell lines showed 400 and 280 chromosomal proteins, respectively, of which about 75% were electrophoretically identical. The two-dimensional gel electrophoretogram of a cloned hybrid mouse erythroleukemia cell line that retained a tetraploid complement of mouse chromosomes and human chromosome 16 (as the only human chromosome) displayed a nonhistone chromosomal protein of pI 6.2 and Mr 65,000. This protein, which comigrates with a nonhistone chromosomal protein present in the human cell line used to produce this hybrid cell and which is also present in two additional human cells lines studied, could not be detected in the mouse erythroleukemia parent before fusion. This polypeptide also was shown by similar techniques to be associated with the presence of human chromosome 16 in four out of five other independently derived hybrid mouse erythroleukemia cell lines that contained a near tetraploid complement of mouse erythroleukemia chromosomes.

Animals↗
PubMed1981

Cardiotoxicity associated with high-dose cyclophosphamide therapy.

The cardiac effects of chemotherapeutic regimens using high doses of cyclophosphamide (180 mg/kg over four days) were assessed in 32 patients with hematologic malignant neoplasms. Left ventricular systolic function, determined by the fractional shortening on echocardiogram, declined substantially five to 16 days after the initiation of cyclophosphamide therapy. Although pericardial effusion on echocardiogram occurred in 33% of the patients studied, ECG voltage decreased five to 14 days after beginning cyclophosphamide therapy even in those patients without pericardial effusion. Congestive heart failure was noted in nine patients (28%) within three weeks of cyclophosphamide administration. Six of these patients (19%) died of myocardial failure. Pericardial tamponade occurred in six patients (19%), including five who died of myocardial failure. Histopathologic and electron microscopic findings showed endothelial injury and a hemorrhagic myopericarditis. Cyclophosphamide in this high dose is associated with a toxic, often fatal, pericardiomyopathy. Depression of ECG voltage and systolic left ventricular function, though common, do not necessarily predict clinical cardiac deterioration.

Adolescent↗
PubMed1981

Selective isolation of young erythrocytes for transfusion support of thalassemia major patients.

Transfusion-induced hemochromatosis remains a major therapeutic complication in the management of thalassemia major patients. Using available blood cell component separators, a system has been devised to selectively harvest young red cells from transfusion support of these subjects. Red cell units isolated by this method have an average estimated mean cell age of 30 days, compared to 60 days for unfractionated blood, and contain 80% of the hemoglobin content of standard red cell units. Radiochromium half-life for young cells measured in 7 asplenic thalassemia major patients averaged 47.4 days compared to 29.5 days for routine frozen red cells. The enhanced survival is not due to reticulocyte enrichment alone, but represents a true cohort of younger red cells. Although costly, this modality could theoretically halve the transfusion requirement in transfusion-dependent patients. When combined with modern iron chelator regimens, it may be possible to achieve consistently negative iron balance prior to the onset of hemochromatosis.

Cell Separation↗
PubMed1980

Expression of human alpha-globin genes in hybrid mouse erythroleukaemia cells depends on differentiated state of human donor cell.

We have developed a system which can be used to study the mechanisms that may govern the expression of human alpha-globin genes in human erythroid and non-erythroid haematopoietic cells. Human chromosome 16, which has been shown to bear the human alpha-globin genes, is introduced by cell fusion into mouse erythroleukemia (MEL) cells to generate continuously proliferating cell lines that retain permanently the human alpha-globin genes. We have shown that hybrid diploid MEL cells with human alpha-globin genes from erythroid donor cells express these genes fully through globin chain synthesis, while hybrid diploid MEL cells containing human alpha-globin genes from non-erythroid human haematopoietic donor cells contain very low levels of human alpha-globin mRNA and no detectable human alpha-globin chains. The levels of human alpha-globin mRNA in these hybrid cells were found to depend on factors present in the MEL recipient cell as well as on the differentiated state of the human donor cell, suggesting that this system may be suitable for characterisation of mechanisms governing haematopoietic differentiation in man.

Animals↗
PubMed1980

Isolation of hybrid cell clones that contain deletion and non-deletion defects of alpha-thalassemia in man.

We have succeeded in isolating hybrid mouse erythroleukemia cell clones from a patient with hemoglobin H disease, which exhibit either deletion or nondeletion mutations of the human alpha-globin genes. Analysis of one of these hybrid clones that had retained a human chromosome 16 from the patient's cells showed that both human alpha-globin had been deleted. Several clones of another hybrid cell had retained a human chromsome 16 from the patient's cells, which contained both human alpha-globin genes on an EcoRI fragment of 23 kilobases (kb). These latter hybrid clones showed the presence of human alpha-globin chains at detectable but low levels. These studies show that there are two different types of human chromosome 16 in this patient and that the nondeletion mutation of human alpha-globin genes leading to hemoglobin H diseases in this patient acts in cis to the two alpha-globin genes remaining in his cells. The close correlation between the pattern of human alpha-globin gene expression in the patient and in the hybrid cells suggests that this method of transfer of human globin genes to rodent cells will be a useful one for study of mutations affecting the expression of differentiated genes that lead to disease in man.

Animals↗
PubMed1979

Activation of phenotypic expression of human globin genes from nonerythroid cells by chromosome-dependent transfer to tetraploid mouse erythroleukemia cells.

Chromosome-dependent gene transfer mediated by cell fusion was used to show that it is possible to activate phenotypic expression of human alpha globin genes derived from nonerythroid cells. Hybrid cells containing the human alpha globin structural genes were derived by fusion of populations of adult human peripheral blood mononuclear cells (devoid of identifiable erythroid cells) with adenine phosphoribosyl-transferase-deficient mouse erythroleukemia cells that contained close to a tetraploid complement of mouse chromosomes. The hybrid cells retained a near tetraploid complement of mouse chromosomes but had lost 80% of the chromosomes of the human parent cell. All of these hybrid cells and their subclones, which contained human chromosome 16, exhibited synthesis of human alpha globin chains. Human alpha globin mRNA was also demonstrated to be present in one of these hybrid cells by RNA.cDNA molecular hybridization analysis. We conclude that the mechanism responsible for restricting expression of the human globin genes in nonerthroid cells is not irreversible, at least for those globin structural genes that are actively transcribed in erythroid cells during adult life. Moreover, some genetic factor or process in the tetraploid mouse erythroleukemia cell is, under the conditions of our experiments, capable of reactivating phenotypic expression (production of globin chains) of human globin genes derived from nonerythroid hematopoietic cells after chromosome-dependent gene transfer.

Animals↗
PubMed1979

Evidence for multiple sites of regulation of heme synthesis in murine erythroleukemia cells.

Friend murine erythroleukemia (MEL) cells can be induced to differentiate along the erythroid pathway by such dissimilar agents as dimethyl sulfoxide (DMSO), butyrate, inhibitors of DNA synthesis, and certain highly polar agents. This study showed differential biochemical effects of the potent inducers DMSO and butyrate on the heme biosynthetic pathway in three clones of Friend MEL cells. When the cells were incubated with combinations of DMSO and butyrate, hemoglobin production was less than that amount produced when each inducer was incubated singly with the cells. Procaine, a local anesthetic that competes with Ca2+ and thus affects membrane permeability, slightly inhibited DMSO-mediated hemoglobin production but almost tripled the level stimulated by butyrate alone. Similarly, EDTA, which also can bind Ca2+ and which can modify the activity of heme biosynthetic enzymes, also inhibited hemoglobin production mediated by DMSO, whereas it stimulated hemoglobin production in cells exposed to butyrate. Total porphyrin accumulation was greater in DMSO-treated cells than in butyrate-treated cells, which suggests that butyrate induces the enzymes of the heme pathway more efficiently than does DMSO. DMSO and butyrate may affect the heme biosynthetic pathway by multiple mechanisms or, alternatively, they may affect the multistep pathway at various points, producing partial blocks or incomplete enzyme induction.

Animals↗
PubMed1978

Chromosomal localization of human beta globin gene on human chromosome 11 in somatic cell hybrids.

We have successfully used a DNA.cDNA molecular hybridization assay to directly determine the presence or absence of human beta globin gene sequences in 20 human-mouse somatic cell hybrids, each of which contained a different subset of human chromosomes. The assay is specific for the individual human globin genes and will detect the presence of a globin gene if the relevant chromosome is present in only 10% of the cells of a hybrid population. The content of human chromosomes in each hybrid clone was characterized by Giemsa 11 staining, Giemsa trypsin-Hoechst 33258 staining, and by the use of 22 independent isozyme markers for 17 different human chromosomes. All human chromosomes were present in one or more cell lines devoid of the human beta globin gene except for 6, 8, 9, 11, and 13. Among these latter chromosomes, only chromosome 11 was present in the six hybrid clones that contained the human beta globin gene. In fact, chromosome 11 was the only human chromosome that was present in all of the six hybrid clones found to be positive for the human beta globin gene. Two sister clones, 157-BNPT-1 and 157-BNPT-4, had similar subsets of human chromosomes except that 11 was present only in 157-BNPT-4. 157-BNPT-4 contained the human beta globin gene while 157-BNPT-1 did not. DNA from three hybrid lines was also annealed to purified human gamma globin cDNA; two lines positive for human beta globin gene sequences also contained human gamma globin gene sequences while one line was negative for both beta and gamma gene sequences. On the basis of these results, the human beta and gamma globin genes have been assigned to human chromosome 11.

Chromosomes, Human, 6-12 and X↗
PubMed1978

Cellular and molecular studies on globin gene expression.

Globin gene expression has been studied with the use of a combination of cell and molecular biology techniques. With a somatic cell hybrid between mouse erythroleukemia (MEL) and human erythroid cells, human and mouse globin genes can be coexpressed in the same hybrid cell. Somatic cell hybridization between MEL cells and nonerythroid cells (e.g., human fibroblasts) results in hybrid cells that cannot be induced to produce hemoglobin of any type. Molecular hybridization of cellular DNA and RNA with globin cDNA indicates that the globin genes are present but that no globin mRNA is in the nonexpressing hybrid cell. This finding demonstrates that the loss of globin gene expression in the hybrid cell occurs at the level of transcription or mRNA processing. The nucleus of the nonerythroid cell is not necessary for the extinction of globin gene expression, since cybrids formed from MEL cells with enucleated nonerythroid cells also result in cells which cannot be induced to synthesize hemoglobin even after 40 or more generations. These data suggest that the cytoplasm of cells contains diffusible regulatory molecules which influence globin gene expression. In our attempt to develop an intracellular assay to test for regulatory molecules, we studied the procedure microinjection with red blood cell (RBC) ghosts. Rabbit globin mRNA (with hemin) was loaded into RBC's and then, by Sendai virus-mediated fusion, into Chinese hamster ovary (CHO) cells growing in culture; these microinjected CHO cells synthesized hemoglobin. Since this microinjection procedure appears to be effective in inserting both proteins and nucleic acids into intact cells, it should be possible to develop modifications for inserting aliquots of fractionated cytoplasm into growing cells. The procedure might then be useful as an assay for putative genetic regulatory molecules.

Animals↗
PubMed1976

Hemoglobin synthesis in somatic cell hybrids: independent segregation of the human alpha- and beta-globin genes.

Hybrid somatic cells containing a partial complement of human chromosomes were used to demonstrate that the human alpha- and beta-globin genes are located on different chromosomes. Two cell lines consisting of a cross of mouse with human fibroblasts contained the human alpha- and not the beta-globin gene, while a cross of human marrow cells with mouse erythroleukemia cells expressed the human beta- but not the alpha-globin gene.

Animals↗