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Biomedical subjects

H Strykowski

Publications and source records attributed to H Strykowski.

17 recordsLinked to original sources
PubMed1993

Muramidase-mediated damage to Candida yeast cells. Histochemical and immunochemical characterization of accumulating wall-like material.

Hen egg-white lysozyme is known to be fungicidal to blastoconidia of Candida albicans under defined in vitro conditions. This lethal action leads to changes in the layering of cell wall and to plasmolysis, caused by unremitting accumulation of wall-like material between the yeast cell wall and cytoplasmic membrane. Here, several methods were applied on ultrathin sections to define the nature of wall-like material: histochemical staining with periodic acid-thiocarbohydrazide-silver proteinate, periodic acid-alkaline bismuth, and phosphotungstic acid at low pH; the localization of the carbohydrate residues with lectin-gold complex; immunocytochemical staining with monospecific antibodies, factor 1 and 6, which recognized major cell wall antigens. The wall-like material was almost uniformly highlighted with periodic acid-thiocarbohydrazide-silver proteinate, factor 1 antibody, concanavalin A-gold and wheat germ agglutinin-ovomucoid-gold, indicating the presence of mannoproteins and chitin. The serotype A-specific epitope recognized by factor 6 antibody was not detected in the wall-like material, although it was demonstrated in the outer cell wall layers after 2 h of exposure to lysozyme.

Antibodies, Monoclonal↗
PubMed1991

Histochemical and immunochemical study of the fate of Candida albicans inside human neutrophil phagolysosomes.

To further define the ultrastructural events associated with the killing of Candida albicans by human neutrophils, four methods were used: (1) the periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining of vicinal-glycol-containing complex carbohydrates; (2) the localization of thermostable immunodeterminants of the yeast cell wall, mannans or mannoproteins, using monospecific antibodies and a protein A-gold complex (monAb-gold); (3) the localization of mannose residues with concanavalin A labeled with gold particles (Con A-gold); (4) the localization of chitin oligomers using wheat germ agglutinin and ovomucoid labeled with gold particles (WGA-gold). The mannan-rich cell wall layers were progressively lost as shown by altered PA-TCH-SP reactivity and a diffuse pattern of staining with Con A-gold and monAb-gold. The de novo appearance of conspicuous amounts of glycogen-like particles near the plasmalemma and in the cell wall was interpreted as evidence of a reparative process of the yeast cell wall. Chitin was seemingly unaltered and readily demonstrated by the WGA-gold in the wall remnants of ghost cells.

Candida albicans↗
PubMed1991

Cell walls of normal and lysozyme-damaged blastoconidia of Candida albicans: localization of surface factor 4 antigen and vicinal-glycol staining.

The fungicidal effect of lysozyme on Candida albicans involves ultrastructural modifications previously described (G. Marquis, S. Montplaisir, S. Garzon, H. Strykowski, and P. Auger, Lab. Invest. 46:627-636, 1982). To further define the action of lysozyme on the yeast cell wall, we used the following: (i) the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method to highlight vicinal-glycol-reactive sites of complex carbohydrates; (ii) a monospecific antiserum and a protein A-gold complex to study the expression of surface factor 4, a major Candida antigen; and (iii) the periodic acid-silver methenamine method to stain cell wall glycoproteins. All Candida cells were found to express surface factor 4 antigen. In normal blastoconidia, surface factor 4 was located in a glycoprotein-rich cell wall layer, underneath radially oriented bundles of filaments which form the outermost wall layer. In lysozyme-treated blastoconidia, this glycoprotein-rich layer was lost and the regular brushlike organization of the outer fibrillogranular layer was disrupted. PA-TCH-SP staining and localization of surface factor 4 antigen demonstrated an altered arrangement of bundles of filaments in the outer wall layers of blastoconidia which were morphologically intact but had abnormal cell wall appearance. Next, there was a reduction in thickness of the outer layer and the expression of surface factor 4 antigen was limited to the cytoplasmic membrane area. Later on, the cell wall was almost uniformly highlighted by PA-TCH-SP staining. These data evinced a highly plastic architecture of the cell wall in C. albicans.

Antigens, Fungal↗
PubMed1990

Implication of mitochondria in the replication of Nodamura virus in larvae of the Lepidoptera, Galleria mellonella (L.) and in suckling mice.

The replication of Nodamura virus, type species of the family Nodaviridae, takes place principally into the interfibrillar spaces of the sarcoplasm in close association with mitochondria in the infected muscles of both G. mellonella and suckling mice. The most striking event in infection of G. mellonella muscle cells was the aggregation and shape modification of numerous mitochondria (elongation, interdigitation, and vesiculation) at an early stage of infection. These clusters of mitochondria were cemented by a thick electron-dense material at the periphery of which viral particles undergo maturation process. In a later stage, degenerated and dilated mitochondria showed a clear assembling of virus particles on their outer membrane and occasionally on some inner membranes. These facts and the localization of RNA by RNase-gold technique in the assembling sites of viruses around and inside the mitochondria allowed us to postulate a role for the mitochondria as supports and/or energy suppliers for viral RNA synthesis and translation.

Animals↗
PubMed1990

Ultrastructure of the human interspinous ligament and ligamentum flavum. A preliminary study.

The ultrastructure of ligamenta flava (LF) and interspinous ligaments (ISL) obtained from four patients who underwent surgery for vertebral fracture (control group) and five patients operated for disc herniation was studied. The fine structure of LF was composed of elastic and elaunin fibers. Small diameter collagen fibrils were found between the elastic system fibers. The ISL was constituted predominantly of collagen fibrils. Elastic fibers were seen in the most ventral part of the ligament. In ISL and LF of the control group, the cells were fibroblastic-like cells. Chondrocytes were present only near their attachment sites. The proteoglycans were demonstrated between the collagen fibrils, and they appeared to form a regular interfibrillar linking. In ligaments obtained from patients with disc herniation, several modifications were found. The fibroblasts transformed into chondrocytic cells, which were surrounded by a pericellular matrix rich in proteoglycan filaments. A few cells that had suffered necrosis were found. Alterations in the collagen-proteoglycans arrangement also were evidenced. The proteoglycan filaments were randomly oriented to the collagen fibrils.

Adult↗
PubMed1990

Production and characterization of monoclonal antibodies to cell wall antigens of Aspergillus fumigatus.

Two murine monoclonal antibodies (MAbs) against Aspergillus fumigatus were produced and characterized. Splenocytes from cell wall-immunized BALB/c mice were fused with SP2/0 myeloma cells. The hybridomas were screened with a cold alkali (CA) extract of mycelium containing protein, mannose, and galactose, and two MAbs of the immunoglobulin M class were purified from ascites fluid. MAbs 1 and 40 were characterized by double immunodiffusion against CA antigen, indirect enzyme immunoassay with mannans of Candida albicans serotypes A or B or Candida tropicalis, indirect immunofluorescence with C. albicans- or A. fumigatus-infected tissues, indirect immunofluorescence with smears of other pathogenic fungi, Western blotting (immunoblotting) with the lectin concanavalin A or BS-1 from the seeds of Bandeirea simplicifolia, and immunoelectron microscopy. MAb 1 did not cross-react with Candida mannan and recognized a periodate-sensitive, pronase- and heat-resistant epitope in CA antigen and three mannose- and galactose-containing components (80, 62, and 49 kilodaltons) of a mycelial homogenate. Immunoelectron microscopy demonstrated binding of MAb 1 to the inner cell wall and intracellular membranes of hyphae and conidia of A. fumigatus. Circulating antigen was detected in experimental invasive aspergillosis by inhibition enzyme immunoassay with MAb 1 and CA antigen. MAb 40 was a nonprecipitating antibody cross-reactive with Candida species, and competition for an epitope located diffusely in the cell wall of A. fumigatus hyphae was demonstrated by incubating MAb 40 with mannan of C. albicans serotype A. These results suggest that MAb 1 recognizes immunodominant oligogalactoside side chains of A. fumigatus galactomannan, while MAb 40 binds to mannopyranosyl side chains common to A. fumigatus galactomannan and C. albicans mannan.

Animals↗
PubMed1989

Ultrastructure and protein A-gold immunolabelling of HRT-18 cells infected with turkey enteric coronavirus.

The Minnesota strain of turkey enteric coronavirus (TCV) was propagated in HRT-18 cells, a cell line derived from human rectum adenocarcinoma. A productive non-cytopathic infection was established, without a previous adaptation, in these cells as shown by the specific hemagglutinating activity in cell culture supernatants. A post-embedding immunochemical technique, using specific antiserum directed against the original egg-adapted virus and colloidal-gold-labelled protein A as the electron-dense marker, was used for the identification of the virus and related antigens in the cells by electron microscopy. Budding of typical coronavirus particles, through intracytoplasmic membranes and accumulation of complete virus within cytoplasmic vesicles or the lumen of rough endoplasmic reticulum, were the main features of the viral morphogenesis. Late in infection, numerous progeny viral particles were shown at the outer surface of infected cells, but budding could not be demonstrated at this level. Two different types of surface projections were observed on the extracellular particles of this avian coronavirus. These morphological characteristics have been thus far described only for mammalian hemagglutinating coronaviruses.

Animals↗
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

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

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↗