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Biomedical subjects

E Baker

Publications and source records attributed to E Baker.

At least 235 records · Page 13Linked to original sources
PubMed1988

Effect of pyridoxal isonicotinoyl hydrazone and other hydrazones on iron release from macrophages, reticulocytes and hepatocytes.

A model consisting of 59Fe-labelled macrophages was developed for screening potential iron-chelating drugs. Mouse peritoneal macrophages, induced by previous intraperitoneal injections of 3% thioglycollate, were labelled in vitro by their exposure to immune complexes of 59Fe-transferrin-antitransferrin antibody. Optimal conditions for macrophage labelling and subsequent 59Fe release were established. Sixty-two aromatic hydrazones, the majority of which had iron binding structures similar to pyridoxal isonicotinoyl hydrazone, were synthesized by condensation of aromatic aldehydes (pyridoxal, salicylaldehyde, 2-hydroxy-1-naphthylaldehyde and 2-furaldehyde) with various acid hydrazides prepared by systematic substitutions on the benzene ring. These compounds were examined for their potential to stimulate 59Fe release from 59Fe-labelled macrophages and also from reticulocytes and hepatocytes loaded with non-heme 59Fe. The majority of hydrazones derived from pyridoxal, salicylaldehyde and 2-hydroxy-1-naphthylaldehyde seemed to be equally effective in both the macrophage and reticulocyte testing systems. However, the pyridoxal hydrazones were much more active in hepatocytes than the other groups of hydrazones. Several compounds proved to be very potent in mobilizing 59Fe. These included hydrazones derived from 2-hydroxy-1-naphthylaldehyde and benzoic acid hydrazide, p-hydroxybenzoic acid hydrazide, 2-thiophenecarboxylic acid hydrazide, and also pyridoxal benzoyl hydrazone, pyridoxal m-fluorobenzoyl hydrazone and pyridoxal 2-thiophenecarboxyl hydrazone.

Animals↗
PubMed1988

The effects of an antibody to the rat transferrin receptor and of rat serum albumin on the uptake of diferric transferrin by rat hepatocytes.

The role of high-affinity specific transferrin receptors and low-affinity, non-saturable processes in the uptake of transferrin and iron by hepatocytes was investigated using fetal and adult rat hepatocytes in primary monolayer culture, rat transferrin, rat serum albumin and a rabbit anti-rat transferrin receptor antibody. The intracellular uptake of transferrin and iron occurred by saturable and non-saturable mechanisms. Treatment of the cells with the antibody almost completely eliminated the saturable uptake of iron but had little effect on the non-saturable process. Addition of albumin to the incubation medium reduced the endocytosis of transferrin by the cells but had no significant effect on the intracellular accumulation of iron. The maximum effect of rat serum albumin was observed at concentrations of 3 mg/ml and above. At a low incubation concentration of transferrin (0.5 microM), the presence of both rat albumin and the antibody decreased the rate of iron uptake by the cells to about 15% of the value found in their absence, but to only 40% when the diferric transferrin concentration was 5 microM. These results confirm that the uptake of transferrin-bound iron by both fetal and adult rat hepatocytes in culture occurs by a specific, receptor-mediated process and a low-affinity, non-saturable process. The low-affinity process increases in relative importance as the iron-transferrin concentration is raised.

Animals↗
PubMed1988

Structure and chromosomal localization of the human renal kallikrein gene.

Glandular kallikreins are a family of proteases encoded by a variable number of genes in different mammalian species. In all species examined, however, one particular kallikrein is functionally conserved in its capacity to release the vasoactive peptide, Lys-bradykinin, from low molecular weight kininogen. This kallikrein is found in the kidney, pancreas, and salivary gland, showing a unique pattern of tissue-specific expression relative to other members of the family. We have isolated a genomic clone carrying the human renal kallikrein gene and compared the nucleotide sequence of its promoter region with those of the mouse renal kallikrein gene and another mouse kallikrein gene expressed in a distinct cell type. We find four sequence elements conserved between renal kallikrein genes from the two species. We have also shown that the human gene is localized to 19q13, a position analogous to that of the kallikrein gene family on mouse chromosome 7.

Amino Acid Sequence↗
PubMed1988

Localization of the human G-CSF gene to the region of a breakpoint in the translocation typical of acute promyelocytic leukemia.

The colony-stimulating factors regulate growth, differentiation, and function of blood cells. The effect of granulocyte colony-stimulating factor (G-CSF) on myeloid leukemias is unique among colony-stimulating factors in driving the leukemic cells from a self-renewing malignant state to a mature differentiated phenotype with the concomitant loss of tumorigenicity. This property of G-CSF has led to suggestions that its absence is responsible for lack of differentiation of leukemic cells and that the therapeutic administration of G-CSF could reverse this defect and result in a cure for leukemia. Here we show that the gene coding for human G-CSF is localized to chromosome 17, bands q11.2-21. The translocation of the long arm of chromosome 17 at q12-21 to chromosome 15 is a specific abnormality occurring in a high proportion of, if not all, patients with acute promyelocytic leukemia, a disease characterized by undifferentiated myeloid cells and a dismal prognosis. Abnormalities of the regulation of a specific differentiation factor gene mediated by a specific chromosomal rearrangement may be directly implicated in the pathogenesis of human leukemia.

Chromosome Mapping↗
PubMed1988

Interleukin 4 is at 5q31 and interleukin 6 is at 7p15.

DNA probes to the human interleukin 4 (IL4) and interleukin 6 (IL6) genes have been used for in situ hybridization to normal human chromosomes and Southern blot analysis of a series of mouse-human hybrid cell lines. IL4 maps to 5q31, the same location as IL5 and other haemopoietic growth factor genes. IL6 maps to 7p15. The significance of these locations is discussed.

Chromosome Mapping↗
PubMed1988

Translocation breakpoint in t(11;14) in B-cell leukemia is not at the rare fragile site at 11q13.3.

The cloned breakpoint at 11q13.3 of the t(11;14)(q13.3;q32.3) in a B-cell lymphocytic leukemia (B-CLL) was used to analyze DNA from individuals with and without the rare folate-sensitive fragile site at 11q13.3. On Southern blots there were no discernible differences. Subclones of the ends of the leukemia breakpoint clone were prepared and used for in situ hybridization to chromosomes expressing fra(11)(q13.3). Both subclones hybridized distal to the fragile site. These experiments indicate that the breakpoints at 11q13.3 in B-CLL (and in a B-cell lymphoma) are not at the fragile site at 11q13.3.

B-Lymphocytes↗
PubMed1988

Human prostate-specific antigen (APS) is a member of the glandular kallikrein gene family at 19q13.

The amino acid sequence of human prostate-specific antigen (APS) suggests that it is a member of the glandular kallikrein subfamily of serine proteases. In the mouse, the kallikrein-like family is localized in a single locus on chromosome 7, while other serine proteases are distributed over a variety of different chromosomes. To investigate the physical relationship between the human kallikrein genes, we have used in situ hybridization and Southern analysis of a human x mouse somatic cell hybrid panel to map the APS gene to 19q13, concordant with the renal kallikrein KLK1 gene. This finding indicates that APS is a member of a human kallikrein-like gene family with analogous organization to that of the mouse.

Antigens, Neoplasm↗
PubMed1988

Menstrual status in female athletes: correlation with reproductive hormones and bone density.

To determine whether the changes induced in serum hormone levels by strenuous exercise are accompanied by changes in bone density, we obtained medical, sports, and dietary histories, trabecular bone density, percentage body fat, and serum hormone concentrations in collegiate athletes for comparison with those of college students not involved in organized strenuous exercise. Several important observations emerged from this study of collegiate athletes. First, the eumenorrheic athletes began sports training earlier than the oligomenorrheic athletes. Second, oligomenorrheic athletes displayed significantly lower serum estradiol concentrations during cycle weeks 2 and 3 but had a rise in this hormone concentration during cycle week 4. Significant differences in serum gonadotropin concentrations during week 4 were found in the oligomenorrheic athletes. Finally, no significant difference in spinal mineral density values was found in the three groups.

Adolescent↗
PubMed1988

Interleukin-5 is at 5q31 and is deleted in the 5q- syndrome.

Human interleukin-5 (IL-5) is a selective eosinophilopoietic and eosinophil-activating growth hormone. By in situ hybridization this gene is mapped to chromosome 5q23.3 to 5q32. It is shown to be deleted in two patients with the 5q-syndrome and in one patient previously diagnosed with myelodysplasia whose condition had progressed to acute myeloblastic leukemia. The clustering of other genes involved in hematopoiesis (IL-3, granulocyte-macrophage colony-stimulating factor, feline sarcoma viral oncogene homolog, colony-stimulating factor 1) to the same region as IL-5 suggests a nonrandom localization and raises interesting questions concerning the evolution and regulation of these genes.

Aged↗
PubMed1988

5-Aminolevulinate synthase is at 3p21 and thus not the primary defect in X-linked sideroblastic anemia.

The gene for 5-aminolevulinate synthase (ALAS) has been mapped to 3pter-3q13.2 by Southern blot hybridization analysis of a mouse/human hybrid cell panel. In situ hybridization maps the gene to 3p21, distal to the common fragile site at 3p14.2 (FRA3B). The mapping of this gene to an autosome makes it improbable that it is the site of the primary defect in X-linked sideroblastic anemia.

5-Aminolevulinate Synthetase↗
PubMed1987

Prenatal diagnosis of the fragile X using thymidine induction.

Eleven pregnancies in ten patients at risk for the fragile X were monitored by amniocentesis or chorion villus biopsy and induction of the fragile site using thymidine, methotrexate and FUdR. Three female fetuses and one male fetus were found to have the fragile X. The results obtained using thymidine induction were superior to those using methotrexate induction and probably better than those obtained using FUdR induction.

Adult↗