Search PubMed⌕ Search

Biomedical subjects

K Rich

Publications and source records attributed to K Rich.

33 records · Page 2Linked to original sources
PubMed1989

Localization of muscle gene products in nuclear domains.

The localization of gene products is central to the development of cell polarity and pattern specification during embryogenesis. To monitor the distribution of gene products encoded by different nuclei in the same cell in tissue culture, we fused cells of different species to form multinucleated non-dividing heterokaryons. In previous fusion studies, cell-surface antigens and organelles contributed by disparate cell types intermixed within minutes. Using heterokaryons produced with differentiated muscle cells, we demonstrate here that a muscle membrane component, the Golgi apparatus mediating its transport, and a sarcomeric myosin heavy chain are localized in the vicinity of the nuclei responsible for their synthesis. These results provide direct evidence that products (organelle, membrane and structural proteins) derived from individual nuclei can remain localized in myotubes, a finding with implications both for neuromuscular synapse formation and for the carrier state of Duchenne muscular dystrophy.

Animals↗
PubMed1989

Cytochrome P450 in highly purified suspension of nonparenchymal liver cells.

Rat liver nonparenchymal cells (NPC) were prepared by pronase digestion and purified on discontinuous gradients on Nycodenz. Morphological and biochemical characterization of cell suspensions showed that they were free of contamination by hepatocytes. We have confirmed the usefulness of pyruvate kinase activity in monitoring the degree of hepatocyte contamination of NPC and we have derived an equation which allows this carry-over to be calculated. Using highly purified suspensions of NPC we have shown that they contain glucose-6-phosphatase in low but detectable levels. Spectrophotometric studies showed that they contain cytochrome P450, with a specific content of 24 +/- 5 pmole mg-1 cell protein. A potential source of error in previous studies was recognized; namely that peroxidase, present in NPC in high concentration, is able to mask the absorption due to cytochrome P450. Both the presence and inducibility of this enzyme in NPC prepared from rats pretreated with phenobarbital or 3-methylcholanthrene have been confirmed using Western blot analysis.

Animals↗
PubMed1985

Pustulosis palmaris et plantaris: its association with chronic recurrent multifocal osteomyelitis.

Palmoplantar pustules may rarely be associated with chronic recurrent multifocal osteomyelitis in children and young adults. Additional features of this disorder are recurrent low-grade fevers and bone pain. Skeletal radiographs and bone films suggest osteomyelitis, but bone cultures yield no growth of organisms. The cause of this disorder is unknown, and treatment remains unsatisfactory.

Child↗
PubMed1983

Hyper IgM immunodeficiency. A primary dysfunction of B lymphocyte isotype switching.

Immunological evaluations (lymphocyte markers, B cell differentiation, T cell function) were performed on peripheral blood mononuclear cells from four individuals with hyper IgM immunodeficiency. Number, proportion, and proliferation of T lymphocytes and T lymphocyte subpopulations were relatively normal in affected individuals. The percentage and number of B cells expressing surface IgM and IgD were either normal or elevated in both blood and lymph nodes. However, surface IgG- and IgA-bearing B lymphocytes were completely absent. In vitro stimulation of blood lymphocytes with both T cell-dependent and T-cell independent polyclonal B cell activators resulted in normal numbers of IgM plasma cells and IgM secretion in cultures, but failed to induce any IgG- or IgA-producing cells. This failure of isotype switching was intrinsic to the B cell population and did not involve aberrant T cell help or suppression. Therefore, individuals with this disorder possess an intrinsic B cell dysfunction that is not related to abnormal T cell regulation.

Adolescent↗
PubMed1981

Documentation of Epstein-Barr virus infection in immunodeficient patients with life-threatening lymphoproliferative diseases by clinical, virological, and immunopathological studies.

Multiple methods, pedigree analysis, clinical evaluation, and Epstein-Barr virus (EBV)-specific serology, EBV DNA hybridization of tissues to probe for viral genome, staining of touch imprints for EBV nuclear-associated antigen, establishment of spontaneous infected B-cell lines from peripheral blood or tissues, examination of peripheral blood smears, and hematopathology studies, were used to study seven patients with the X-linked lymphoproliferative syndrome and seven additional patients with life-threatening EBV-associated diseases. These studies demonstrated EBV in the tissues of all 14 patients and immunodeficient antibody responses to EBV were documented. This virus can produce various life-threatening lymphoproliferative diseases in a variety of immunodeficient patients.

Adolescent↗
PubMed1979

Purine nucleoside phosphorylase deficiency: biochemical properties and heterogeneity in two families.

The biochemical features of two families with purine nucleoside phosphorylase deficiency are compared. Laboratory studies and an evaluation of kinetic and physical properties of erythrocyte purine nucleoside phosphorylase give evidence that a) the degree of abnormality in uric acid and nucleoside concentrations in plasma and urine reflect the severity of the enzymatic deficiency and b) structural alterations of the mutant enzymes result from structural gene mutations and demonstrate genetic heterogeneity in the disease purine nucleoside phosphorylase deficiency.

Child↗
PubMed1977

Abnormal in vitro granulopoiesis in phenotypically normal parents of some children with congenital neutropenia.

Bone marrow from hematologically normal parents of congenitally neutropenic children showed defective myeloid differentiation in vitro. In one family only the mother's marrow differentiated abnormally; in the second family both parents demonstrated abnormal myeloid differentiation. In vitro culture of bone marrow may be useful in establishing the mode of inheritance of some forms of familial neutropenia.

Adult↗
PubMed1977

Evaluation of congenital neutropenic disorders by in vitro bone marrow culture.

The congenital neutropenias are a heterogenous group of diseases whose etiology and pathogenesis are largely unknown. We studied nine neutropenic patients from seven families. Evaluation included peripheral blood cell and differential cell counts, epinephrine and typhoid vaccine stimulation studies. Rebuck skin windows, and bone marrow aspirations for morphological assessment and for in vitro culture in liquid suspension and in agar plates. Parallel cultures were set up with and without colony-stimulating activity (CSA), and peripheral leukocytes were assayed for cellular production of CSA. Patients were initially classified on the basis of their clinical course: benign, mild, moderately severe, or severe disease. One patient in the moderately severe group had an immunoglobulin disorder. Morphologically normal mature granulocytes were seen in bone marrow aspirates of two patients, and maturational defects of varying degree were seen in the remaining seven. Colony formation in agar was markedly reduced below normal in three of seven, moderately reduced in two of seven, and greater than normal in two patients. Colonies in six of seven patients consisted exclusively of macrophages. Marrow from all but one of the nine patients demonstrated poor neutrophil development in suspension culture, and addition of CSA did not result in augmented granulocytic proliferation or maturation. A scheme of normal neutrophil maturation is proposed, and the nine patients were categorized according to this scheme. Four patterns of congenital neutropenia emerged: type 1 was the most benign form of disease with essentially normal clinical and in vitro parameters, and a defect considered to be due to a small committed stem cell pool, abnormal release, or excessive utilization peripherally; type 2 had mild disease with presumed defective committed stem cell differentiation along the granulocyte line; type 3 included benign to severe clinical expression with an apparent defect at the level of the committed granulocyte precursor more severe than in type 2; type 4 disease had varied clinical expression but evidence for a defect at the level of the pluripotent stem cell.

Adult↗