Biomedical subjects

M Grob

Publications and source records attributed to M Grob.

At least 37 records · Page 2Linked to original sources

PubMed1996

[Liberation into the wild of wild felines--danger of the release of virus infections].

There are several felidae amongst the numerous endangered species. Means of aiding survival are the reintroduction to the wild of animals bred under the auspices of man and their relocation from densely populated to thinly populated areas. It is unlikely that the dangers of such reintroduction or relocation projects have been examined sufficiently in respect to the risks of virus infections confronting individuals kept in zoos or similar situations. This report presents three examples to illustrate that accidental virus infections may be expected to occur when relocating and reintroducing wild cats. The first example is the reintroduction of captive snow leopards. Zoo bred snow leopards may be infected with FIV, a virus infection that is highly unlikely to occur in the original himalayan highlands of Tibet and China. A second example is of several cases of FIP that occurred in European wild cats bred in groups in captivity. The third example mentioned is the relocation of lions from East Africa where all the commonly known feline viruses are wide-spread to the Etosha National Park. In the latter, virus infections such as FIV, FCV and FPV do not occur. The indiscriminate relocation and reintroduction of the wild cats mentioned here harbours a potential of undesirable consequences.

Animals↗

PubMed1995

Panleukopenia-like syndrome of FeLV caused by co-infection with FeLV and feline panleukopenia virus.

To study the effect of interferon on feline leukemia virus (FeLV) infection, 30 specific pathogen free (SPF) cats were infected with the apathogenic FeLV A Glasgow. Unexpectedly, between 5 and 8 weeks after FeLV infection, all 19 cats with persistent FeLV infection but not the FeLV-negative cats died from a panleukopenia-like syndrome. No feline panleukopenia virus (FPLV) antigen was found in feces by latex agglutination, enzyme-linked immunosorbent assay (ELISA) or immunoelectron microscopy. No enteropathogenic bacteria were found. Histopathology revealed changes resembling those of FPLV infection such as destruction of crypts and pancytopenia of bone marrow. Neither clinical signs nor seroconversion to FPLV could be induced by transmitting intestinal extracts to two SPF cats. However, FPLV antigen was demonstrated by immunofluorescence assay in intestinal cryostat sections of diseased animals. FPLV could also be demonstrated in intestinal extracts by immunoelectron microscopy, by latex agglutination and ELISA after anti-FPLV antibodies were removed from immune-complexed FPLV by ultracentrifugation over a CsCl gradient at pH 2.0. From these experiments it was concluded that the panleukopenia-like syndrome of FeLV may not be caused by FeLV alone but at least in some cases by co-infection with FeLV and FPLV. In addition, some form of 'cooperation' between FeLV and FPLV must be postulated because neither virus alone induced symptoms.

Animals↗

PubMed1992

The cytoskeletal protein talin is O-glycosylated.

Talin is a 215-kDa cytoskeletal protein implicated in linking actin filaments to the plasma membrane. We show here that chicken gizzard talin is galactosylated by incubation with UDP-[3H]galactose and galactosyl-transferase. The labeled carbohydrate moiety is removed by beta-elimination and comigrates with Gal beta 1-4GlcNAcitol, indicating that talin belongs to a recently discovered class of cytosolic proteins carrying N-acetylglucosamine (GlcNAc) O-linked to serine or threonine (Holt, G. D., and Hart, G. W. (1986) J. Biol. Chem. 261, 8049-8057). Two glycosylated sequences were identified in the tail domain of talin: ANQAIQMAXQNLVDPAXTQ and GILANQLTNDYGQLAQQ, corresponding to amino acids 1470-1488 and 1883-1899, respectively, of the mouse talin amino acid sequence (Rees, D. J. G., Ades, S. E., Singer, S. J., and Hynes, R. O. (1990) Nature 347, 685-689). The putative glycosylation sites are PAXTQ and QLTND. At most 6% of chicken gizzard talin and 3% of porcine stomach talin are galactosylated by galactosyltransferase. Furthermore, human platelet talin is not labeled at all by the procedure, indicating that it may not be glycosylated.

Amino Acid Sequence↗

PubMed1991

[Deficiency in immunoglobulin subclasses as cause of increased infection susceptibility--a family study].

Within 3 generations 6 members of a family showed diminished serum concentrations of one or more immunoglobulin G (IgG) subclasses. In all 6 individuals IgG-2 levels were low, together with low IgG-3 and/or IgG-4 in 5, but all had normal values for total IgG. The proposita and her 2 children suffered from frequent severe respiratory infections. One child, now aged 11, has had an average of 3 such infections per year since birth, while the other, now aged 8 years, has had 4 episodes annually since birth. Recurrent infection only started at age 34 in the proposita. In these 3 patients a line immuno-binding assay showed diminished subclass-specific IgG-2 antibodies against bacterial polysaccharides. They were replaced by Sandoglobulin, an immunoglobulin for intravenous use. Under substitution by 6 g or 12 g infusions of Sandoglobulin per month no further infections occurred or the infections were clearly milder than before, and the Ig subclass levels became normal. It is concluded that in every case of recurrent respiratory infections of unusual severity suggesting an antibody deficiency, it is advisable to measure not only the total Ig classes (IgG, IgA and IgM) but also the IgG subclasses. The clinical relevance of an Ig subclass deficiency can be further substantiated by measuring subclass-specific antibodies.

Adult↗

PubMed1991

[Healed (?) amoebic keratitis].

Acanthamoeba keratitis was seen in two contact-lens wearers. In both cases, this finding was verified by microbiological examination of conjunctival swabs and of the lens solution. One patient had perforating keratoplasty. While neither vital amoebae nor cysts could be detected in the host corneal explant, immunohistochemical examination revealed fluorescence-positive fragments which probably correspond to incomplete cycstic walls.

Acanthamoeba Keratitis↗

PubMed1989

Inhibition of exocytosis by intracellularly applied antibodies against a chromaffin granule-binding protein.

Exocytotic secretion requires the interaction and fusion of secretory vesicles with the plasma membrane. This process could be mediated by specific recognition molecules acting as intracellular, membrane-bound receptors and ligands. One possible component of such a recognition site on the plasma membrane is a protein of relative molecular mass (Mr) 51,000 (51K) that has been isolated from bovine adrenal chromaffin cells. This protein binds strongly to chromaffin granules, the secretory vesicles of these cells. To determine the function of this membrane-anchored chromaffin granule-binding protein in exocytosis, we tested the effect of intracellularly injected antibodies on secretion. Here we show, by two independent techniques in two different cell types, that antibodies against this protein inhibit exocytosis. In rat pheochromocytoma cell cultures, monospecific antibodies, applied by erythrocyte ghost fusion, impair the release of 3H-noradrenaline. The same antibodies, introduced into individual chromaffin cells through a patch pipette, block exocytosis, as revealed by the measurement of membrane capacitance. These results demonstrate the functional involvement in exocytosis of a plasma membrane protein with high affinity for secretory vesicles.

Adrenal Medulla↗

PubMed1989

The lipoxygenase pathway and chemiluminescence in horse eosinophilic leukocytes.

It was shown in several cell types that the dual lipoxygenase and cyclooxygenase inhibitor eicosatetraynoic acid but not the cyclooxygenase inhibitor acetylsalicylic acid suppressed luminol-dependent chemiluminescence. Since lipoxygenase is known to generate chemiluminescence in vitro, these observations were interpreted as evidence for a direct contribution of the lipoxygenase pathway to light emission in intact cells. We have investigated a possible contribution of the lipoxygenase to the chemiluminescence of horse eosinophils by directly comparing the formation of the byproduct chemiluminescence with the formation of stable end-products of the lipoxygenase pathway, leukotrienes and HETEs. Azide as well as eicosatetraynoic acid almost completely inhibited chemiluminescence stimulated by the calcium ionophore A23187 but had less effect on the formation of leukotrienes. The tumour-promoting ester, phorbol myristate acetate, stimulated chemiluminescence in an azide- and eicosatetraynoic acid-sensitive manner and failed to evoke the production of leukotrienes. Azide, but also eicosatetraynoic acid inhibited the luminol-dependent chemiluminescence generated by isolated eosinophil peroxidase in the presence of H2O2. Our results argue against a direct role of the lipoxygenase pathway in the generation of light in horse eosinophilic leukocytes but do not exclude that product(s) of this pathway may be involved in stimulus-response coupling.

Animals↗

PubMed1987

Detergents inhibit exocytosis in PC 12 cells: evidence for an effect on ion fluxes.

Membrane events in exocytosis were studied by examining the effect of different detergents on the K+-stimulated release of noradrenaline in the secretory cell line PC 12. The nonionic detergent Triton X-100 and the cationic detergent cetyltrimethylammonium bromide (CTAB) inhibit the noradrenaline release evoked by 55 mM K+ by 50% at very low concentrations (30 microM and 10 microM, respectively). These values are tenfold lower than the critical micellar concentrations (CMC). No such effect was seen with the anionic detergent sodium dodecyl sulphate (NaDodSO4). The inhibitory effect of 30 microM Triton X-100 is reversible, and the recovery from inhibition correlates with the loss of detergent from the cells as demonstrated by binding studies using [3H]Triton X-100. The possible relationship between this inhibition of secretion and the structural properties of the detergent was investigated. The inhibition in the presence of purified Triton X-100 subfractions turned out to be a function of the length of the oligometric ethyleneglycol chain (C6 to C26). The maximal effect was observed for Triton X-100 molecules having a chain length of 16 carbon atoms, which can penetrate just half of the lipid bilayer of the membrane. Additionally, the phase transition at 13-14 degrees C observed in an Arrhenius plot of noradrenaline release in stimulated cells was abolished. In the presence of 30 microM Triton X-100, 22Na+ uptake, 86Rb+ release, and 45Ca2+ uptake were reduced by 50-60%. These data suggest that the site of action of Triton X-100 is at the level of altering the movement of ions in PC 12 cells during the stimulatory phase of secretion.

Adenosine Triphosphate↗

PubMed1987

Virus-induced formation of reactive oxygen intermediates in phagocytic cells.

Viruses cause disease by a wide variety of mechanisms. These include the impairment of differentiated host cell functions and the killing of infected cells. The latter is referred to as cytopathic effect and is exemplified by Polio virus infection where paralysis results from the loss of neurons killed by the virus. Host immune response as a factor contributing to disease is evident in the skin rashes in measles and rubella. Virus-immune complexes occur in many infections and may be associated with glomerulonephritis and arthropathy. We describe two mechanisms by which viruses activate the generation of reactive oxygen intermediates (ROI) in polymorphonuclear leukocytes. The first is mediated by antiviral antibody and hence is controlled by the immune system. The second mechanism depends on a direct interaction of viral antigen with the plasma membrane of the phagocyte. It is suggested that the direct activation of ROI generation by paramyxo- and influenza viruses may be related to their well-known toxic effects in vivo.

Animals↗

PubMed1986

Reliability of data taken from medical charts.

While it is desirable to conduct clinical research across different institutions using the richness and complexity of daily clinical data from the hospital chart, it is possible only if reliable information can be obtained. This report represents the efforts made by eight collaborating private psychiatric hospitals to devise two instruments to provide reliable rating and notation of clinical information found in the medical record. Such information will spawn future studies of applied clinical research.

Data Collection↗

PubMed1982

Single dose pharmacokinetics of fendiline in humans.

Fendiline was administered intravenously (3 mg) and orally (50 mg and 75 mg) in a cross-over study to six healthy volunteers. The plasma levels of unchanged fendiline and of total radioactivity were measured. Fendiline was absorbed well and its concentration declined biexponentially with mean terminal half-lives of 20-35 h. Since the drug is extensively metabolized, only 12% of total radioactivity in plasma corresponded to fendiline in the case of intravenous administration as compared to less than 2% after oral administration. 56-65% of the administered dose are excreted via the urine and 18-25% with the feces within five days.

Adult↗

PubMed1973