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M Z Doymaz

Publications and source records attributed to M Z Doymaz.

8 recordsLinked to original sources
PubMed1995

A sensitive staining method for NORs.

A sensitive staining method for nucleolar organizer regions (NORs) is described, using blue toning of AgNORs. NORs are loops of DNA which are transcribed into ribosomal RNA. NORs can be demonstrated by staining with silver nitrate, since NOR-associated proteins are argyrophilic, producing structures termed AgNORs. Normal blood lymphocytes were stained with both methods. The number and resolution of NORs increased 2-3 times by blue toning (30 mmol/l FeCl3, 11 mmol/l potassium hexacyanoferrate(III), and 33 mmol/l oxalic acid) compared with silver staining. A significant difference in the number of NORs was noticed between silver-stained and blue-toned cells (P < 0.001). The blue toning technique thus appears to be more sensitive in detecting NORs than the AgNOR method and may prove a useful alternative for applications in histopathology.

Chlorides↗
PubMed1992

Herpetic stromal keratitis: an immunopathologic disease mediated by CD4+ T lymphocytes.

To investigate the role of T cell subsets in the development of herpetic stromal keratitis (HSK) in a well defined model, we used an adoptive transfer approach in which thymectomized and T cell-depleted mice [T(-)] were reconstituted with different numbers of syngeneic immune T lymphocytes after topical corneal challenge with RE strain of herpes simplex virus-1. In vitro stimulated or unstimulated immune T cells obtained from cervical and retropharyngeal lymph nodes of mice with HSK were used in adoptive transfer experiments. Although T(-) mice developed an initial epithelial inflammation, stromal keratitis did not occur. Reconstitution experiments revealed that mice that received 2 x 10(7) or more unfractionated immune T cells could develop HSK lesions with severity comparable to immuno-competent control mice. In mice receiving CD8(+)-depleted populations, even fewer cells (5 x 10(6)/mouse) were able to induce significant HSK. In contrast, mice that received similar or increased numbers of cells depleted of CD4+ T lymphocytes did not develop HSK. Immune T lymphocytes transferred to mice that were mock infected on the cornea did not develop HSK, indicating that the immunopathogenic cells were virus specific and not merely reacting to autoantigens. Histopathologic examination of the diseased corneas demonstrated that the stromal inflammation in euthymic normal and T(-)-reconstituted mice was characterized by extensive polymorphonuclear leukocyte infiltration. Scattered lymphocytes, and occasional macrophages also were observed. These results provide further evidence that HSK represents an immunopathologic process mediated mainly by CD4+ T cells.

Animals↗
PubMed1991

MHC II-restricted, CD4+ cytotoxic T lymphocytes specific for herpes simplex virus-1: implications for the development of herpetic stromal keratitis in mice.

Herpetic stromal keratitis (HSK) appears to represent an immunopathological reaction in which CD4+ T cells play a prominent role. However, the exact immunopathological mechanism(s) utilized by CD4+ T cells during HSK remains to be elucidated. In this study, the presence of cytotoxic CD4+ T lymphocytes in the cervical and retropharyngeal lymph nodes of Balb/c mice experiencing HSK was investigated. After in vitro depletion of CD4+ or CD8+ T cells with specific monoclonal antibodies and complement treatment, the cytotoxic functions of the remaining T cell populations were assayed by using target cells expressing either MHC Class I or both Class I and Class II. Our results showed the presence of a distinct cytotoxic T lymphocyte (CTL) population which was CD4+ and demonstrated lytic activity in a Class II-restricted fashion. Furthermore, these cells were able to develop into efficient effector CTL in the absence of CD8+ T lymphocytes as assessed by in vivo depletion experiments. Immunohistochemical methods were also utilized to show the presence of both CD4+ lymphocytes and I-A+ cells in the corneal tissues during HSK. These findings support the notion that direct lysis of infected Class II-bearing corneal cells by CD4+ CTL might be one of the mechanisms leading to stromal immunopathology in herpetic infections.

Animals↗
PubMed1990

Distribution of immunoglobulin-bearing leukocytes in bovine mammary tissue infected chronically with Staphylococcus aureus.

Mammary parenchymal and test end tissues from cows with chronic Staphylococcus aureus mastitis were examined to determine the distribution of immunoglobulin (Ig) G1- and IgG2-bearing leukocytes. Leukocytes bearing IgG2 predominated in S. aureus infected quarters, with highest numbers observed at the Furstenberg's rosette followed by streak canal and parenchymal tissue areas. Significantly more IgG1- and IgG2-bearing leukocytes were observed at the Furstenberg's rosette and significantly more IgG2-bearing leukocytes were observed at the streak canal of S. aureus infected quarters compared to uninfected quarters. Receptors for cytophilic IgG on neutrophils and macrophages may increase efficiency of phagocytosis and improve the antimicrobial effectiveness of these cells in treat end tissues.

Animals↗
PubMed1989

Leukocytic infiltration of bovine mammary parenchymal tissue in response to Corynebacterium bovis colonization.

Morphological changes and local leukocyte response to prolonged Corynebacterium bovis colonization were studied in lactating bovine mammary glands. Morphometric analysis of parenchymal tissue demonstrated no adverse effects of colonization on the synthetic and secretory activity of mammary epithelium. Numbers of macrophages, lymphocytes, and plasma cells were higher in tissue from C. bovis-colonized quarters. However, there were no differences in numbers of neutrophils between colonized and uninfected quarters. Results suggest persistent C. bovis colonization may elicit effector cell populations in lactating mammary tissue where leukocyte concentrations tend to be lower.

Animals↗
PubMed1989

Morphological study of chronic Staphylococcus aureus mastitis in the lactating bovine mammary gland.

Pathological changes and leucocyte response to chronic Staphylococcus aureus mastitis were studied in bovine mammary glands. Less synthetic and secretory activity was evident in quarters with chronic mastitis than in control quarters as indicated by a distended stromal area, diminished alveolar lumina, and epithelia without secretory characteristics. Ultrastructural examination demonstrated decreased cell area occupied by cytoplasmic organelles which further substantiated impaired synthetic ability. Leucocyte infiltration into the stroma, epithelial lining and lumina was more marked than in uninfected tissue. However, prolonged exposure to S aureus mastitis appeared to interfere with the antigenic stimulation of B lymphocyte precursor cells into plasma cells. Involution and loss of alveolar function may have been associated with extensive leucocyte diapedesis into luminal spaces and, or, potentially harmful staphylotoxins.

Animals↗
PubMed1988

Effects of Staphylococcus aureus mastitis on bovine mammary gland plasma cell populations and immunoglobin concentrations in milk.

Bovine mammary tissue and milk samples were examined to determine effects of chronic Staphylococcus aureus mastitis on the humoral immune response. Parenchymal and teat end tissues from lactating bovine mammary glands were stained immunohistochemically to determine distribution of immunoglobulin (Ig) G1-, IgG2-, IgA-, and IgM-producing plasma cells. Numbers of all Ig-producing plasma cells tended to be higher in tissues from S. aureus infected quarters compared with controls, but most differences were not statistically different. Numbers of IgG1-producing plasma cells at the Furstenberg's rosette area of infected quarters were significantly (P less than 0.05) higher than uninfected quarters. There were no significant differences in concentrations of Ig isotypes in milk from S. aureus infected and uninfected quarters. Data suggest that the antigenic effect of chronic S. aureus infection on the humoral immune response of the bovine mammary gland is minimal. Persistency of S. aureus infection may result, in part, from suboptimal stimulation or immunosuppression of the mammary immune system.

Animals↗