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Biomedical subjects

S Garzon

Publications and source records attributed to S Garzon.

At least 37 records · Page 2Linked to original sources
PubMed1989

Degeneration of the human lumbar spine ligaments. An ultrastructural study.

The fine structural alterations in human lumbar spine ligaments were studied in tissue samples obtained from 8 young patients operated upon for idiopathic scoliosis and from 10 adult patients operated upon for herniated discs. The ultrastructure of the scoliotic ligaments was found to be normal. The majority of cells encountered were the fibroblastic-like cells. The collagen-proteoglycans interaction was similar to that described in other normal soft tissues. However, two forms of degenerative changes were demonstrated in posterior ligaments of patients with herniated discs. Metaplasia of ligamentous tissue into fibrocartilage was a common finding. The fibroblasts were replaced by chondrocytes. A few cells which had suffered necrosis were found. Alterations in the collagen-proteoglycans arrangement were also evidenced. This form of degeneration resembled that commonly associated with wear and tear phenomena. A second form of degeneration due to ageing was found to coexist with the aforementioned alterations.

Adolescent↗
PubMed1989

Isolation and trypsin-enhanced propagation of turkey enteric (bluecomb) coronaviruses in a continuous human rectal adenocarcinoma cell line.

Turkey enteric coronavirus (TCV) from intestinal contents of diarrheal poults was isolated and serially propagated in HRT-18 cells, an established cell line derived from a human rectal adenocarcinoma. In these cells, TCV induced cytopathic changes, including polykaryocytosis, which depended on trypsin in the medium and incubation at 41 C. Viral antigens could be demonstrated in the cytoplasm by immunofluorescence, and extracellular virus was detected by an ELISA and negative electron microscopy. The cell-free virus had characteristics of TCV: shape, surface projections, buoyant density of 1.18 to 1.20 g/ml in sucrose, and hemagglutination of rat RBC. The one-step growth curve was complete by postinoculation hours 14 to 16, and maximal titers reached 9 to 9.5 log10 TCID50/ml during 5 passages, after which the titer remained stable. Electron microscopic examination of infected cell monolayers revealed budding of typical coronavirus particles through intracytoplasmic membranes and accumulation of complete virus in cytoplasmic vesicles. Late in the infection, aggregated progeny vial particles were detected near the outer surface of infected cells. One-day-old turkey poults inoculated orally with tissue culture-adapted TCV isolates developed mild to severe diarrhea.

Adenocarcinoma↗
PubMed1988

Protein G-gold complex: comparative evaluation with protein A-gold for high-resolution immunocytochemistry.

We combined the protein G-gold complex with several polyclonal and monoclonal antibodies for localization of various antigenic sites. The labelings were compared with those obtained using the protein A-gold complex. The results from either the immunodot experiment or immunoelectron microscopy have demonstrated that, for rabbit and guinea pig antibodies, both protein G-gold and protein A-gold complexes label several different specific antibodies with similar efficiency. However, with antibodies raised in goats or in mice, and particularly with mouse monoclonal antibodies, protein G-gold yielded intense and specific labeling, whereas protein A-gold yielded intense and specific labeling, whereas protein A-gold was very variable; it either gave weaker signals or failed to reveal any specific site or, as with one monoclonal, both protein G and protein A gave similar results. The higher affinity and versatility of protein G over protein A, established by the immunochemical approach, was confirmed by immunocytochemistry. Because of its enhanced reactivity with monoclonal antibodies and its broader affinity for polyclonal antibodies, protein G-gold complex appears to be a better and more versatile probe for high-resolution immunocytochemistry.

Amylases↗
PubMed1988

Mechanisms of HIV-associated immunosuppression.

HIV antigens were identified in PBL obtained from HIV-positive patients, using IF and IEM. Studies of the phenotype of HIV-containing lymphocytes showed that OKT4+ cells were the principal target of the virus. Approximately 5% of infected cells were multinucleated. Almost all infected and about 30% of uninfected PBL displayed Ab-C3 complexes on the cell surfaces. Sera from HIV-positive patients contained Ab reacting with cell membranes and intracellular structures of PBL from normal subjects, as demonstrated by IEM. The presence of Ig-C3 complexes on a high percentage of HIV-positive- or negative-PBL suggests that the Ab-C-mediated lympholysis may represent a major mechanism of lymphatic tissue destruction in HIV-infected patients.

Autoantibodies↗
PubMed1986

Detection of HTLV-III/LAV antigens in peripheral blood lymphocytes from patients with AIDS.

HTLV-III was searched for in frozen sections of peripheral blood lymphocytes obtained from AIDS patients by an immunofluorescence technique. Human IgG against HTLV-III/LAV and monoclonal antibodies against HTLV-III/LAV P 24 antigen, yielded a strong cytoplasmic fluorescence in frozen sections of the lymphocytes. Some cells containing HTLV-III antigens displayed multinucleated giant forms. They also reacted with monoclonal antibodies against helper/inducer T-cells (OKT4+), as demonstrated by direct double staining immunofluorescence. Similarly, complexes of immunoglobulins and C3 component of complement were also detected on HTLV-III/LAV Ag expressing lymphocytes. Immunofluorescence study of frozen sections of peripheral blood lymphocytes appeared to be a simple, fast and reliable method for detection of HTLV-III/LAV Ag in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Dedifferentiation of a transplantable papillary thyroid carcinoma over a 15-year period.

Fischer 344 rats on a prolonged low-iodine diet developed thyroid nodules which were transplanted subcutaneously into 33 thyroidectomized rats. One graft took and gave a papillary carcinoma. Serially transplanted syngeneically at 3- to 4-month intervals, it became autonomous in third generation hosts. With electron microscopy examination it was microfollicular in year 8 and anaplastic, with totally unpolarized epithelial cells, in year 15. Basement membrane present in year 1 was no longer visible in specimens of years 8 and 15. Tight and gap junctions still present in year 8 were absent in year 15, although a few desmosomes persisted. From years 8 to 15, free ribosomes and microfilaments became more frequent, whereas the number of mitochondria and the development of the Golgi complex declined.

Animals↗
PubMed1982

Ultrastructural localization of viral antigens using the protein A-gold technique.

HSV and DNV viral antigens have been localized by electron microscopy using the protein A-gold technique. The labelling of HSV antigens was detected over the (naked and enveloped) viral particles as well as on the cytoplasm and the nucleoplasm. In contrast, DNV antigens were revealed only over clusters of viral particles in the nucleus. The high sensitivity of the technique and the good ultrastructural preservation allowed a very fine identification of the labelled structures. Thus, the protein A-gold technique can be applied generally for the ultrastructural detection and identification of viral antigens and might be useful for diagnostic purposes.

Animals↗
PubMed1982

Fungitoxicity of muramidase. Ultrastructural damage to Candida albicans.

The antifungal activity of hen egg-white lysozyme was investigated in vitro using a hypotonic medium designed to support an anabolic cellular state with minimal growth stimulation. The pathogenic yeast Candida albicans was found to be sensitive to microgram amounts of hen egg-white lysozyme. This susceptibility was evidenced by sluggish growth and a dose-dependent killing process. Transmitted and scanning electron microscopic observations on lysozyme-treated C. albicans yeast cells revealed the following ultrastructural modifications: (1) plasmolysis, vacuolar expansion and wrinkled surface configuration; (2) unremitting accumulation of wall-like material that bulged into the periplasmic space; (3) qualitative changes in the organization of the wall. Ongoing structural modifications within the wall were highlighted with the cationic heavy metal dye ruthenium red. A disruption in the permeability of the cytoplasmic membrane was evidenced by modification 1 and by differential staining characteristics in light microscopy. The superimposed osmotic imbalance was identified as the cause of cell death. It is proposed that lysozyme acts on C. albicans by two distinct complementary mechanisms: enzymatic hydrolysis of N-glycosidic bonds that link polysaccharides and structural proteins of the wall; injury to the cytoplasmic membrane as a result of a cationic protein kind of interaction.

Candida albicans↗
PubMed1980

Naturally occurring R.ColBM plasmids belonging to the IncFIII incompatibility group.

Two Escherichia coli strains isolated from urinary tract infections were resistant to streptomycin, kanamycin, neomycin, tetracycline and sulphonamides. The strains also produced colicins B and M. The resistance to streptomycin, kanamycin and neomycin and the ability to produce colicins B and M could be transferred to an E. coli K12 recipient. Resistance and colicinogeny markers were transferred together by conjugation, and did not segregate even after interrupted mating or phage P1-mediated transduction. Hence, the drug-resistance and colicinogeny markers were carried by the same plasmid, designated as R.ColBM plasmid. The two R.ColBM plasmids were Fi+ and produced an F-like pilus. They belonged to the IncFIII incompatibility group, being thus the first R plasmids identified in this group. The two plasmids were isolated and their molecular sizes were determined by electrophoresis in agarose gels and by contour length measurements. Both methods showed that both plasmids were about 52 megadaltons.

Bacteriocin Plasmids↗
PubMed1980

Rodent incisor pulp, isolation and sectioning.

Experimental technics are described for a quick isolation of the dental incisor pulp in rodents, and for the wrapping of the pulp in a sheet of guinea pig muscle as a prerequisit for cryostat sectioning.

Animals↗
PubMed1978

Morphogenesis of the nodamura virus in the larbae of the lepidopteran Galleria mellonella (L.).

The pathogenesis and morphogenesis of the Nodamura virus, an insect picorna- virus which can also infect vertebrates such as newborn mice, are described in the larvae of G. mellonella. Examination of thin sections of muscle, salivary and moulting glands, hemocytes adipose tissue and hypodermis of the infected larvae of G. mellonella shows in the cytoplasm the accumulation of viral particles either dispersed or in a stringlike or paracrystalline array. These arrays of virions can be within membrane- bound vesicles. Helical filaments of 110 A of diameter can be observed inside the basal membranes and later in the cytoplasm, in relation to the infection of muscular or adipose tissues. The morphogenesis of Nodamura virus in G. mellonella or in suckling mice is very similar to that of the Coxsackie A virus observed in the mouse.

Animals↗