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Biomedical subjects

Z Chen

Publications and source records attributed to Z Chen.

At least 1,603 records · Page 89Linked to original sources
PubMed1986

Immunological typing of acute lymphoblastic leukemia: concurrent analysis by flow cytofluorometry and immunocytology.

For 60 cases of acute lymphoblastic leukemia (ALL) immunological typing was done concurrently by the avidin-biotin-peroxidase method using cytocentrifuged smears and by flow cytofluorometry for the study of surface antigens. The use of a large panel of antibodies detecting differentiation antigens allowed us to sub-classify 57/60 cases as 43 B-lineage ALLs and 14 T-lineage ALLs. The two types of ALL can be accurately distinguished by the expression of the antigens recognized by the antibodies of the clusters of differentiation CD19 (B4) and CD7 (Leu 9). Almost perfect agreement was obtained between the results of the two methods for antigens DR, CD10 (cALLA;J5) and CD7. A number of discordances were observed with other antigens [CD19 (B4), CD20 (B1), CD22 (To15), CD1 (T6), CD2 (T11), CD4 (T4), CD8 (T8), CD3 (T3), T9, T10]. In spite of these discordances, the avidin-biotin-peroxidase method can predict the lineage involved in most ALLs with a high degree of reliability. Nevertheless, for weakly expressed surface antigens (such as B4 and B1) the immunocytological method is less sensitive than flow cytofluorometry and can only approximately determine the stage of differentiation of neoplastic cells. Furthermore, the existence of cases which are at the same time negative with flow cytofluorometry and positive with immunocytology is consistent with the intracytoplasmic expression of certain differentiation antigens. Thus in the course of lymphoid differentiation, intra-cytoplasmic expression of T3, To15 and possibly J5 precedes their expression at the cell surface.

Antigens, Surface↗
PubMed1986

Mononuclear cell phenotypes in patients with psoriasis.

Mononuclear blood cells from 19 patients with psoriasis were stained with a panel of monoclonal antibodies which detect total T lymphocytes, their helper/inducer and suppressor/cytotoxic subsets and Ia-positive lymphocytes and monocytes. Fluorescence-positive cells were enumerated by cell flow cytometry. In these patients, percentages of all mononuclear cell studies were within reference range with few, sporadic exceptions. Statistical analysis of data showed no significant differences between patient values and reference values from a panel of 100 normal subjects.

Adult↗
PubMed1986

Isolated frog olfactory cilia: a preparation of dendritic membranes from chemosensory neurons.

The recently introduced frog olfactory cilia preparation (Chen and Lancet, 1984; Pace et al., 1985) has been useful for studies of molecular chemosensory mechanisms. Here we describe in detail the properties of this cilia preparation. The "calcium shock" procedure leads to a complete removal of the cilia from the olfactory epithelial surface. Isolated cilia constitute segments of proximal regions with 9 X 2 + 2 microtubular arrangement and a large proportion of membrane vesicles, probably derived from the ciliary distal segments. Polypeptides unique to the olfactory cilia preparation, compared to a control preparation of palate respiratory cilia, are identified by Coomassie brilliant blue staining, silver staining, and radiolabeled lectin overlays, as well as by biosynthetic labeling with 35S-methionine in epithelial explants and protein phosphorylation in isolated cilia. The olfactory cilia preparation contains odorant-sensitive adenylate cyclase, which is absent in control membranes from deciliated epithelium. High activities of tyrosine and serine/threonine protein kinases are also present. The olfactory cilia preparation described should be instrumental in the further elucidation of the biochemistry and molecular biology of vertebrate olfaction.

Adenylyl Cyclases↗
PubMed1985

Direct and indirect immunofluorescent findings in dermatomyositis.

Three skin biopsies (proximal nailfold, extensor forearm and buttock) and serum samples were studied by direct and indirect immunofluorescence, immunodiffusion and radioimmunoassay techniques in 6 patients with dermatomyositis. A variety of serologic and immunopathologic abnormalities was observed in the patients. Three of 6 patients had antinuclear antibodies (ANA) of a speckled pattern mixed with a peculiar dot pattern. Epidermal intercellular deposits of immunoglobulins were seen in the nailfold biopsies of 2 patients; one of them also had IgG deposits in the cytoplasm of epidermal cells. Forearm and buttock biopsies were negative.

Adolescent↗
PubMed1984

Characterization of a monoclonal antibody reactive with rabbit T lymphocytes and neutrophils.

An IgG1 monoclonal antibody, termed ACM-1, has been shown to react with rabbit T cells, but not Ig+ cells or macrophages. This antibody appears to recognize the same epitope as the previously described 9AE10 antibody and, together with 9AE10, has been used to obtain highly pure and fully functional T- and B-cell populations. However, the relevant epitope does not appear to be homologous to rodent Thy-1 since quantitative absorptions failed to show reactivity with rabbit brain. Furthermore, attempts to obtain in vivo T-cell depletion resulted in larger decreases in white blood cells than would be expected for simple T-cell removal. In vitro assays on enriched neutrophil preparations revealed that 80-95% of these cells were reactive with ACM-1 and 9AE10. Thus, it appears that in the rabbit, T cells and neutrophils share a major epitope.

Animals↗
PubMed1984

Ameloblastoma of the mandible treated by resection, preservation of the inferior alveolar nerve, and bone grafting.

The results of five cases of ameloblastoma of the mandible treated by resection, preservation of the inferior alveolar nerve, and immediate bone grafting are reported. The incisions in all cases healed by first intention. Lip sensation on the operated side returned to normal in four to six weeks in four cases and slight numbness persisted to the eighth week in one case. All patients were followed postoperatively for 13-15 years. In one case the tumor recurred in the mucous membrane seven years after surgery at the original intraoral site and invaded the underlying bone graft. The indications and contraindications for surgery and details of the procedures, including measures to prevent recurrence, are presented.

Adolescent↗
PubMed1984

Membrane proteins unique to vertebrate olfactory cilia: candidates for sensory receptor molecules.

In search for olfactory receptor molecules, we carried out comprehensive electrophoretic mapping of membrane proteins in the cilia of frog olfactory epithelium. Seven polypeptides, extracted from isolated cilia by nonionic detergent, were unique to the sensory organelles, compared to nonsensory (respiratory) counterparts. Olfactory cilia contained 3-10 times more membrane-associated protein as compared to respiratory cilia, in agreement with reported densities of freeze-fracture intramembranous particles. Four of the olfactory polypeptides were major constituents of the ciliary membrane, each amounting to greater than 10% of its total protein. Three major and one minor specific polypeptide were glycosylated, whereas membranes of nonsensory cilia were practically devoid of glycoproteins. A clear difference in surface composition was also shown by microscopic visualization of fluoresceinated lectin bound to intact isolated cilia. Two of the olfactory glycoproteins displayed pronounced heterogeneity of apparent molecular weight, which could partly be due to protein sequence diversity, as expected for odorant receptor molecules. The recently described inhibition of odorant-evoked sensory potentials by the lectin concanavalin A is consistent with the hypothesis that one or more of the specific glycoproteins described here plays a role in olfactory reception.

Animals↗
PubMed1984

3AE8: monoclonal antibody defining inflammatory macrophages in three species.

A mouse monoclonal antibody (MAb 3AE8) of the IgG1 isotype was prepared against rabbit splenocytes and was found by indirect immunofluorescence and direct binding assays to react, in the rabbit, primarily with oil-induced peritoneal exudate macrophages (PEM phi). This MAb did not bind to rabbit T cells, B cells, polymorphonuclear leukocytes, or resident alveolar or peritoneal M phi but it did bind to a subpopulation of rabbit splenocytes with surface characteristics of null cells. The antibody also recognized mouse and rat PEM phi as well as the murine M phi cell lines P388D1 and IC-21. Consistent with findings in the rabbit, it did not bind to M phi obtained from the peritoneal cavities of rats or mice. The addition of MAb 3AE8 to mouse PEM phi caused a marked enhancement in the phagocytic uptake of erythrocyte target cells sensitized with a mouse antierythrocyte antiserum.

Animals↗
PubMed1984

Cerebral response to medullary pyramid stimulation in the rabbit.

The response evoked in the cerebral cortex of the rabbit by stimulation of the medullary pyramid was studied electrophysiologically. The response was everywhere surface-positive and began 2-3 ms after the stimulus. It exceeded 1 mV in amplitude and generally lasted 2-4 ms. Maps of the response showed it to extend throughout the anterior one-third of the cortex (in the 'motor' cortex) and into adjacent tissue, including the limbic cortex. Although it depended on antidromic conduction in pyramidal tract fibers for its production, it varied in amplitude, configuration and latency at different sites and at the same sites on repeated trials. It was found to reverse polarity deep in the cortex, to become a large, negative wave in layer V and to maintain that polarity into the underlying white matter. The response disappeared during a spreading depression, though it recovered more rapidly than the primary response evoked by skin stimulation. Maps of the primary response showed a strong overlap with the 'antidromic' response, though the response was largest slightly caudal to the maximal focus of the 'antidromic' response and extended more caudally through transitional and into limbic cortex. The 'antidromic' response showed two major foci on the cortex, with an additional minor focus located more laterally. It is argued that the 'antidromic' response in the rabbit is the same as that found in the opossum, woodchuck, rat and slow loris, and is markedly different from that found in the cat and macaque monkey. It is postulated that this response reflects synaptic action in pyramidal tract axon collaterals, probably onto cell bodies in layer V, rather than being a purely antidromic event.

Animals↗
PubMed1984

Role of prostaglandins in pathogenesis of bovine mastitis induced by Escherichia coli endotoxin.

Four doses (5 to 100 micrograms, 1 dose/quarter) of Escherichia coli endotoxin were introduced into lactating mammary glands of 2 cows. There was no effect on milk prostaglandin (PG) E2 concentration, except that the concentration was increased from 200 pg/ml of milk to 1,060 pg/ml at post-treatment hour (PTH) 8 in cow 1 and from 75 to 420 pg/ml at PTH 4 in cow 2 after the highest dose 100 micrograms. Endotoxin caused a dose-dependent increase in milk PGF2 alpha concentrations in both cows. After the highest dose, PGF2 alpha was maximally increased from 200 to 3,500 pg/ml at PTH 4 in cow 1 and from 250 to 2,000 pg/ml in cow 2 at PTH 8. The instillation of 50 micrograms of endotoxin in all 8 quarters of 2 more lactating cows caused no significant (P greater than 0.05) changes in milk PGE2 and thromboxane B2 concentrations, whereas milk PGF2 alpha was significantly increased from the base-line value of 642 to 2,683, 1,189, and 2,281 pg/ml at PTH 4, 8, and 12, respectively. The 6-keto-PGF1 alpha was also significantly increased from the base-line value of 305 to 871, 631, and 600 pg/ml at the corresponding times, respectively. A marked increase in vascular permeability, as judged by high concentrations of serum albumin in the whey, was observed as early as PTH 4 and peaked at PTH 12 followed by a gradual decline, although it remained significantly increased over the control for 48 hours after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

A comparative study of glucose oxidase versus FITC-labeled antibody techniques for the detection of antinuclear antibodies.

Sera from 98 patients were examined for antinuclear antibodies (ANA). The patient population has been previously identified clinically as having the following diseases: systemic lupus erythematosus, scleroderma, dermato or polymyositis, discoid lupus, rheumatoid arthritis, Raynaud phenomena only, undifferentiated connective tissue disease, and psoriasis. All sera samples were tested using both HEp-2 cells and rat kidney tissue as substrates and were stained with both fluorescein-conjugated antihuman antibody and glucose oxidase-conjugated antibody to human IgG. Each serum was initially tested at a screening dilution of 1:40 with PBS. Positive sera were serially diluted until an end point was observed. The number of dilutions for each specimen in all four combinations was compared mathematically using the Pearson product moment correlation. Using this method, glucose oxidase- and fluorescein-conjugated antinuclear antibody (FANA) techniques appear to have a high positive correlation (r = 0.92 kidney, r = 0.95 Hep-2) in this patient population. In our experience, the glucose oxidase technique offers comparable results to FANA and is ideally suited for the hospital laboratory, especially facilities without the benefit of a fluorescent microscope.

Antibodies, Anti-Idiotypic↗