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Biomedical subjects

J Metz

Publications and source records attributed to J Metz.

At least 163 records · Page 9Linked to original sources
PubMed1981

Enterohepatic circulation of cobalamin in the nonhuman primate.

Biliary excretion of cobalamin was studied in baboons after intravenous injection of 57Co-radiolabeled cyanocobalamin. Radioactivity appeared in bile after 20 min, and up to 4.4% of the dose was recovered in 6 h. It was estimated that 4 microgram cobalamin traverses the baboon biliary tract each day. These studies in the nonhuman primate confirm that there is considerable biliary excretion of cobalamin and that enterohepatic circulation of the vitamin is important for maintenance of normal cobalamin balance.

Animals↗
PubMed1981

[Excessive allergy due to benzoic acid followed by anaphylactic shock. (author's transl)].

The case of a trained chemical worker highly sensitive to benzoic acid is described. He suffered from allergic reactions of increasing intensity while being constantly exposed to benzoic acid during work. After oral exposure to benzoic acid he suffered a severe anaphylactic shock and later on showed similar but milder reactions when eating food containing benzoic acid. No allergic reactions reoccurred avoiding every contact with benzoic acid especially observing a strict benzoic acid-free diet.

Adult↗
PubMed1980

Utilization of [2-14C]tetrahydropteroylglutamic acid and 5-[G-3H]methyltetrahydropteroylglutamic acid as substrates for folate polyglutamate synthesis in fruit bats: effect of vitamin B-12-deficiency.

[2-14C]Tetrahydropteroylglutamic acid and 5-[G-3H]methyltetrahydropteroylglutamic acid were given intraperitoneally to fruit bats. Folate polyglutamates were formed in the liver from both substrates in different amounts and at different rates. The methylfolate pool appeared to remain separate from the tetrahydrofolate pool. More polyglutamate was formed from tetrahydropteroylglutamic acid than from 5-methyltetrahydropteroylglutamic acid. There was a fall in the folate content of the liver in the vitamin B-12-deficient bat and a more rapid incorporation of folates into polyglutamates but thereafter a more rapid loss of the labelled folate from liver.

Animals↗
PubMed1980

Intercellular junctions in the full term human placenta. II. Cytotrophoblast cells, intravillous stroma cells and blood vessels.

Intercellular junctions within the villous stroma and the cytotrophoblastic layer of the human full term placenta were investigated using thin sectioning and freeze-fracturing. Numerous maculae adherentes (desmosomes) were found between the cytotrophoblast cells and the syncytiotrophoblast. This junction type was also seen connecting adjacent cytotrophoblast cells. Large gap junctions were frequently observed in contact areas of perikarya or at processes of adjacent fibroblasts. They often exhibited a peculiar pattern of their particles on the P-face of the membrane. Small rows of junctional particles were found on the P-faces of interconnected smooth muscle cells and gap junctions frequently bridged myoendothelial and interendothelial contact zones. The significance of the junctional complexes is discussed in relation to functional systems within the villous stroma of the human full term placenta.

Blood Vessels↗
PubMed1980

On the developing rat placenta. I. Differentiation and junctional alterations of labyrinthine layers II and III.

The differentiation of chorionic layers II and III and alterations of intercellular junctions within the developing placental labyrinth were investigated in rats. Between the 14th and 16th day of gestation, the trabecular structures of the labyrinth alter and increasing numbers of primary, secondary, and tertiary lamellae develop. Trophoblastic layer I remains multicellular. Layer III rearranges and cytoplasmic fusions result in a continuous cytoplasmic barrier intervening between the already syncytial trophoblastic layer II and fetal capillaries. Simultaneously, most of the "undifferentiated" cells within the labyrinth disappear. Thin sectioning anf freeze-fracturing reveal multiple images of intercellular junctions, particularly gap and tight junctions in the cellular and syncytial parts of layers II and III. Continuous and regularly arranged tight junctions occur as well as fragmented structures which are spaced irregularly. Gap junctions are occasionally found between the juxtasinusoidal regions of layers II and III on the 14th day. More often they occur within restricted areas near the center of the trabeculae, integrated within extensive tight junctional strands. Gap junctions increase in later stages of pregnancy and eventually become distributed between the interfaces of layers II and III in the primary lamellae.

Animals↗
PubMed1980

Renin in the uterus of pregnant mice. Immunocytochemical, ultrastructural and biochemical studies.

The distribution and content of renin in the uterus of pregnant mice (12--14 days of gestation) was studied by immunocytochemistry, electron microscopy and radioimmunoassay. The uterine renin concentration at this stage of pregnancy was four-fold higher than that of the nonpregnant uterus but still less than 0.1% of the kidney renin concentration. Renin was localized almost exclusively in the decidual and entodermal epithelial linings of the yolk sac (uterine) cavity near the marginal sections of the placenta. By electron microscopy granular and vesicular structures were observed in the renin containing epithelial cells. Chorioallantoic placenta, myometrium, decidua basalis and the antimesometral parts of the epithelial leafs of the uterine cavity did not contain renin. The specific localization of renin suggests a role in parturition or delivery of the placenta.

Animals↗
PubMed1980

Renin in the uterus of non-pregnant mice. Immunocytochemical, ultrastructural and biochemical studies.

The distribution of renin in the uterus of non-pregnant mice was studied by immunocytochemistry, using the peroxidase-antiperoxidase (PAP) technique, by electron microscopy and biochemical renin estimation. By immunocytochemistry, two separate localizations of renin could be identified, one in the apical region of the endometrial cells, the other in perivascular cells of the myometrium. The renin concentration in the endometrium, as determined cytochemically, and the total renin content of the uterus, as estimated enzymatically, varied with the ovarian cycle, being highest during the oestrus and lowest during the post-oestrus phase. The electronmicroscopic finding of the fluctuations in the granule content of the epithelial cells was in accordance with the immunocytochemical and biochemical data.

Animals↗
PubMed1980

Descriptive studies of H-reflex recovery curves in psychiatric patients.

The rate of recovery of the H-reflex, an electrical evoked monosynaptic spinal cord reflex, was abnormally high (fast) in over 20% of unmedicated psychotic patients of all major diagnostic classes. A few patients had significantly lower H-reflex recovery curves. Chronic neuroleptic treatment produced relatively lower recovery curves, whereas fluoxetine, a specific serotonin uptake blocker, produced relatively higher curves.

Adolescent↗
PubMed1980

Synthesis of DNA as shown by the deoxyuridine suppression test is normal in the vitamin B12-deficient fruit bat (Rosettus Aegyptiacus).

1. DNA synthesis in the bone marrow and lymphocytes of the vitamin B12-deficient fruit bat (Rosettus Aegyptiacus) has been studied via the deoxyuridine (dU) suppression test. 2. In contrast to vitamin B12 deficiency in man, the dU suppression test was not abnormal in the vitamin B12-deficient bat, and this correlates with the reported finding that the latter does not develop megaloblastic anaemia. 3. The protection of haemopoiesis from vitamin B12 deficiency in the bat is probably related to the presence in the bat of separate pools of methylfolate and tetrahydrofolate, which enables the bat to overcome the trapping of methylfolate attendant on vitamin B12 deficiency. 4. These results confirm the central role of the vitamin B12 and folate-dependent pathway of de novo synthesis of DNA in the pathogenesis of vitamin B12-deficient megaloblastic anaemia.

Animals↗
PubMed1980

Characterization of bone marrow stromal cells in suspension and monolayer cultures.

Aspirated marrow fragments from healthy adult baboons were cultured in a simple liquid suspension tissue culture system. During the incubation period, haemopoietic cells were discharged from the fragments and settled to the floor of the culture vessels, thus allowing a separation of marrow stromal elements, retained within the fragments. Cells associated with the marrow stroma in vitro were of four main types: adipocytes, macrophages, plasma cells and unidentified lipid-laden cells related to fibroblasts. These last cells were capable of DNA synthesis in vitro, and were morphologically and functionally distinguishable from typical marrow macrophages. Macrophages were characterized by their phagocytic properties. Plasma cells were capable of prolonged survival and immunoglobulin output in vitrol. In monolayer cultures of disaggregated fragment cell suspensions, the lipid-laden stromal cells rapidly assumed fibroblast-like morphology. Fibroblastic proliferation to confluent monolayers was seen within a few days. Plasma cells reorientated themselves around these cells to form rosettes, and bridge communicatons between the two cell types were seen frequently. Plasma cell immunoglobulin output rate per cell appeared to be potentiated by this association.

Animals↗
PubMed1980

Separation of normal mature bone marrow plasma cells.

A three-phase purification process for the separation of normal bone marrow plasma cells is described. Material was obtained from haematologically normal humans and baboons. Known monoclonal and polyclonal B cell activators were avoided both in vivo and in vitro. In Phase I, bone marrow fragments were separated from cell suspensions by buoyant density methods. Marrow fragments were shown to be richer in plasma cells than the corresponding marrow cell suspensions. Phase II consisted of culturing fragments by a simple suspension method in which a selective affinity of plasma cells and marrow stromal cells resulted in further concentration of plasma cells with discharge of haemopoietic elements. Maximum concentration of plasma cells occurred within 7 d. In phase III, fragments were disaggregated with trypsin, and the marrow stromal cells were removed by their adherence properties. The resulting non-adherent fraction comprised approximately 85% plasma cells. The process allows for direct quantitative evaluation of normal plasma cell physiology in vitro.

Animals↗
PubMed1980

Vitamin C allergy of the delayed type.

A case of vitamin C allergy of the delayed type is reported. Eczematous skin lesions appeared during normal uptake of the vitamin C contained in food. After a vitamin C-free diet, the skin lesions disappeared. Patch tests and an oral exposure with vitamin C gave positive reactions. This observation of vitamin C allergy is compared with previous published cases.

Ascorbic Acid↗