[Study of the ultimobranchial body, with morphological and experimental research in Athene noctua].
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Animals↗
Biomedical subjects
M Lupetti
Publications and source records attributed to M Lupetti.
Purine metabolism and B-lymphocyte development in the chicken bursa of fabricius.
The activity of three enzymes involved in the salvage pathway of purine nucleosides--purine nucleoside phosphorylase (PNP), xanthine dehydrogenase (XDH), and hypoxanthine-guanine phosphoribosyl transferase (HGPRT)--was investigated in cellular fractions of the chicken bursa of Fabricius differentially enriched in epithelial cells or lymphocytes. Markedly increasing levels of PNP and XDH were observed along with the enrichment in epithelial cells together with a slight, though significant, decrease in HGPRT activity. By contrast, a dramatic fall in PNP and XDH activities was detected along with the enrichment in lymphocytes together with a slight, though significant, increase in HGPRT activity. This sharply different distribution of the three enzymes, all sharing hypoxanthine as a substrate, clearly indicates that lymphocytes preferentially channel hypoxanthine into the salvage and interconversion pathways, phosphorylating it to IMP, while epithelial cells rapidly catabolize such a purine base to uric acid. Moreover, epithelial cells, unlike lymphocytes, are able to retain high intracellular levels of both hypoxanthine and inosine. These results support the possibility that epithelial cells contribute to the normal development of bursal lymphocytes by supplying such actively proliferating cells with purine rings and at the same time by preventing them from accumulating potentially toxic high levels of purine nucleotides being able to rapidly eliminate excess hypoxanthine as uric acid from the bursa environment into the bloodstream.
Animals↗
The use of MAB 1977 monoclonal antibody for the immunohistochemical localization of beta 1 integrins in paraffin-embedded human kidney.
AIMS AND BACKGROUND: Integrins are widely known cell membrane receptors for extracellular matrix molecules. The beta 1 integrin subgroup is mainly expressed by kidney cells; immunolocalization of these molecules is usually carried out on cryostatic sections. A commercial monoclonal antibody directed against the human beta 1 integrin was tested in order to design a method for the detection of this antigen in formalin-fixed, paraffin-embedded human kidney tissue. METHODS: Specimens obtained from nephrectomies were fixed with 10% formalin and embedded in paraffin. Three different detection protocols were applied after incubation with the anti-human beta 1 integrin monoclonal antibody (MAB 1977): 1) immunoperoxidase with labeled streptavidin biotin (LSAB), using biotinylated secondary antibodies, peroxidase-labeled biotin-streptavidin, and 3,3'-diaminobenzidine tetra-hydrochloride (DAB) as the revealing system; 2) immunoperoxidase with tyramide signal amplification (TSA), using biotinylated secondary antibodies, streptavidin-peroxidase, tyramide, streptavidin-peroxidase again and DAB; 3) indirect immunofluorescence with fluorescein-labeled anti-mouse immunoglobulins. RESULTS: The beat results were obtained with the LSAB detection protocol preceded by a predetection step with proteinase k. Proteinase k pretreatment did not significantly damage the tissue morphology and successfully unmasked beta 1 integrin antigens. Nonspecific background staining was reduced by a blocking step with swine serum. Similar results were obtained with the TSA detection method; however, although lower concentrations of anti-beta 1 integrin immunoglobulins and of secondary biotinylated antibody were employed, there was more undesired background staining than with the LSAB protocol. CONCLUSIONS: The method reported and discussed here may represent a valid tool for research and diagnostic applications based upon detection of beta 1 integrin in paraffin-embedded human tissues.
Adenocarcinoma, Clear Cell↗
Changes in the chicken bursa of Fabricius and immune response after treatment with melatonin.
Since melatonin causes considerable reduction in the thymic weight of chickens, the aim of the present study was to find out whether the bursa of Fabricius and the immune response are also affected by this substance. The results show that melatonin also acts on the bursa of Fabricius depending upon the administration route. When injected subcutaneously it does not reduce bursal weight and the histological pattern does not change, while primary and secondary immune responses are significantly lowered. When melatonin is introduced into the bursa, it causes a considerable decrease in bursal weight and the histological pattern is greatly modified. A significant reduction in antibody production is observed involving the primary immune response alone. Transmission electronic microscopy seems to show that melatonin affects the reticulo-epithelial (REp) cells.
Animals↗