Biomedical subjects
Publications and source records attributed to B Fernandes.
A case of acute typhlitis arising in a neutropenic male is described. Light and electron microscopy reveal findings resembling those of an early stage of malakoplakia. The coexistence of these two uncommon lesions suggests a pathogenetic role in the development of septicemia in immunocompromised hosts.
Malignant transformation of murine and human cells is commonly associated with increased--GlcNAc beta 1-6Man alpha 1-6Man beta--branching in asparagine-linked oligosaccharides. Somatic mutations and drugs which block expression of the beta 1-6 branched oligosaccharides are potent inhibitors of tumor cell invasion and metastasis in animal models. This suggests that the oligosaccharides are required for metastasis to occur and therefore their increased presence in primary tumors may be diagnostic of metastatic disease. Although antibodies to the beta 1-6 branched portion of the oligosaccharides are not available, a plant lectin leukoagglutinin (L-PHA) has been shown to bind specifically to this structure. L-PHA lectin histochemistry was performed on paraffin sections of human breast and colon tissues. All breast carcinomas and epithelial hyperplasia with atypia showed significantly increased L-PHA staining compared to fibroadenomas and hyperplasia without atypia. In histological sections of colon, adenomas showed a small but significant increase in L-PHA staining compared to normal colonic epithelium, while carcinomas showed greatly increased reactivity. In addition, Dukes stage C tumors showed higher levels of L-PHA staining than stage A tumors. These results demonstrate that L-PHA-reactive beta 1-6 branched N-linked oligosaccharides are consistently increased in neoplasias of human breast and colon and that the level of L-PHA staining correlates with the pathological staging of the diseases.
Two patients with acquired deletions of the long arm of chromosome 5 (5q-) are presented and discussed. For both, clinical and other laboratory tests are highly atypical of patients with haematological malignancy characterized by 5q-. These unusual presentations of the 5q- anomaly further emphasize the heterogeneity of clinical presentations associated with this acquired chromosomal abnormality.
In this work an immunohistochemical method was used to study the ontogeny and phylogeny of a terminal N-acetylglucosamine (GlcNAc) cluster antigen which is an epitope(s) of highly branched N-linked oligosaccharides terminating in GlcNAc residues. The ontogenic studies demonstrated that expression of the antigen is developmentally regulated in lymphocytes, epithelial cells of endodermal origin and kidney mesangial cells of the chicken. The antigen was found in several other avian species studied, namely, the Japanese quail, duck, goose and turkey. Furthermore, the distribution of the antigen in all these species was similar. In adult animals, it was found in bursal and thymic lymphocytes, macrophages, spleen reticulum cells, epithelial cells of the intestine and bronchioles and capillary endothelial cells. The antigen was also detected in epithelial cells of the gastrointestinal tract of several lower vertebrates studied: the amphibian (frog), reptile (chameleon) and fish (rainbow trout). It was undetectable in various organs of the human, African green monkey, calf, pig, rat and guinea-pig, but was found in the intestinal epithelial cells of ten mouse strains. It is likely that biosynthetic processing leading to the formation of highly branched N-linked glycans terminating in GlcNAc residues is conserved during evolution in birds and other lower vertebrates.
In a series of approximately 400 patients investigated for oligospermia 4 had small testicular tumors demonstrated by high resolution real-time ultrasound. The lesions ranged in size from 3 to 6 mm., were clinically impalpable and were demonstrated on repeated sonograms. Exploration was done in all 4 patients with the aid of intraoperative high resolution ultrasound. This procedure allowed for conservative resection of the tumor with preservation of the testicle. The pathological diagnosis in all cases was benign Leydig cell tumor.
We have previously described a chicken heterophile antigenic determinant (CHAD-1) shared by Mycobacterium smegmatis and chicken tissues. We then demonstrated that CHAD-1 is present on several chicken glycoproteins and that its immunoreactive domains are highly branched asparagine-linked oligosaccharides terminating in N-acetylglucosamine residues. In the present study, we have shown that CHAD-1 is also expressed by mucin purified to homogeneity from a soluble mucus of chicken intestine. Another antigen found on chicken mucin is a chicken mucin-cross-reactive antigen (CMCRA). Antisera to this antigen were produced by immunization of rabbits with an enriched preparation of CHAD-1 isolated from the bursa of Fabricius. These antisera were absorbed with Mycobacterium smegmatis (to block the anti-CHAD-1 antibody) and with chicken serum, and then used for immunoperoxidase staining of chicken tissue sections for CMCRA. The latter antigen was detected in most medullary cells of the bursa, in epithelial cells and Hassal's corpuscles of the thymus, and in mucus-producing cells of the intestine, esophagus, trachea, and bronchi. Using Western immunoblot analysis, we demonstrated that CMCRA is expressed by a number of polypeptides extracted from bursal lymphoid cells. These polypeptides could not be detected in extracts of thymus, spleen, peripheral blood or bone marrow mononuclear cells.
Mouse bone marrow cells were fractionated and enriched for functional activity as stimulators of allospecific cytolytic T-lymphocyte (CTL) responses in vitro. The relevant stimulator cells were enriched sequentially in the low-density fraction of bone marrow, its 2-hr adherent and 18-hr non-adherent fractions and in the FcR-negative fraction of 18-hr non-adherent cells. The functionally enriched cell population contained over 90% granulocyte precursors by ultrastructural analysis. The results indicate that granulocyte precursors are the principal cells in bone marrow that stimulate alloreactive T-cell responses.
A novel heterophile antigen shared by Mycobacterium smegmatis and chicken tissues was demonstrated by the indirect immunoperoxidase method using antisera raised in rabbits immunized with a complete Freund's adjuvant containing killed Mycobacterium smegmatis as an immunostimulating component. This antigen was strongly expressed in medullary lymphocytes of the thymus and bursa of Fabricius, but was undetectable in lymphoid cells of the cortical regions of these organs. Only a few lymphocytes stained positively for the antigen in T- and B-cell areas of the spleen. These data suggest that the heterophile antigen is associated with the intrathymic and intrabursal maturation of chicken lymphocytes. The antigen was also detected in some nonlymphoid cells. It was not found in sheep erythrocytes, human and rat tissues or in killed bacillus Calmette--Guerin.
As the AIDS epidemic unfolds, many newly described clinical syndromes resulting from unusual manifestations of opportunistic infections are being seen. The authors report the clinical and pathological features of intestinal perforation in an AIDS patient caused by extensive small-bowel ulcerations due to cytomegalovirus. The diagnosis was confirmed by ultrastructural and immunohistochemical studies. It is suggested that infection and destruction of the muscularis propria by the virus contributes to intestinal perforation.
Immunomorphological methods were used to localize adenosine deaminase in tissues of the rat at different stages of ontogeny. In the thymus, lymphocytes began to express significant amounts of the enzyme with the appearance of demarcation between the cortex and medulla at 17 days of gestation. At any stage of ontogeny studied, strong adenosine deaminase staining was seen predominantly in cortical thymocytes. In the spleen and lymph node, the enzyme was initially detected in T cell areas, whereas primary follicles did not show positive adenosine deaminase staining. During further development, the enzyme was demonstrated in some lymphocytes of germinal centres and plasma cells. In the duodenum, epithelial cells of villi and the neck of crypts showed positive adenosine deaminase staining whereas no staining for the enzyme was observed in the epithelial cells of the base of crypts. Strongly positive staining for adenosine deaminase appeared in plasma cells of the lamina propria by four weeks after birth. The transient positive reaction for the deaminase could be recognized in epithelial cells of tubules of the kidney during late foetal and early postnatal development. The tubules of adult rats did not stain for the enzyme. In the cartilage of 15-day foetuses, positive adenosine deaminase staining was seen only in perichondrial cells and hypertrophic cells. Kupffer cells in the liver and endothelial cells of blood vessels stained positively for the enzyme at every stage of ontogeny studied.
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Immunomorphologic methods were utilized to localize adenosine deaminase (ADA) in extrathymic benign lymphoid tissues and B-cell lymphomas. In reactive lymph nodes, tonsils and appendix, germinal centers displayed strong ADA-positive nuclear staining in small cleaved lymphocytes and weak nuclear and/or cytoplasmic staining in large lymphoid cells. A significant proportion of ADA-positive lymphocytes in the germinal centers were B-cells. The mantle zone of secondary follicles did not stain for ADA. The plasma cells in the medullary cords demonstrated mainly cytoplasmic staining. In the spleen, ADA-positive lymphocytes were located in the periarteriolar sheath and paratrabecular white pulp. In lymphoma B-cells, patterns of ADA staining were similar to those observed in normal B-lymphocytes of similar morphology. This study demonstrated that human normal and lymphoma B-lymphoid cells are heterogeneous with respect to ADA expression. This heterogeneity appears to be associated with differentiation and/or proliferation of B-lymphocytes.
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2'-Deoxycoformycin (DCF) is a potent inhibitor of adenosine deaminase (ADA) and a potential antineoplastic and immunosuppressive agent. In this study the kinetics of ADA expression was assessed by immunomorphologic and enzymatic methods in tissues of ACI rats given injections of DCF. The rats received a daily ip injection of 10 mg DCF/kg for 3 consecutive days. This treatment destroyed cortical thymocytes, whereas lymphocytes of the thymic medulla were mainly preserved. In control phosphate-buffered saline-injected rats, cortical thymocytes were not affected morphologically and displayed strong ADA staining. It was found unexpectedly that injections of DCF produced activation and, possibly, differentiation of B-cells in the mesenteric lymph nodes and spleen. These activated B-lymphocytes and plasma cells stained strongly for ADA. Transient changes in patterns of ADA expression were also observed in endothelial cells of blood vessels and liver Kupffer's cells, but these changes were not accompanied by degeneration of the cells. The treatment with DCF did not result in any permanent abnormalities in the rat tissues.
The author reviews the the conceptions of Hubertus Tellenbach on the occasion of the french translation of his book Geschmack und Atmosphere... He noticed the importance of "atmospheric evaluation" in psychopathology and considers a large field of applications in literary critic.
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This article is a report on the initial year of operation of the Arthritis Minimal Care Unit at the University of Texas Medical Branch at Galveston. The unit provided a comprehensive program for patient with arthritis including an interdisciplinary approach to care and patient-oriented program development with emphasis on patient and family education. The results of our program showed that hospital admission time and cost could be reduced and an improved quality of care could be provided in a Minimal Care Unit as compared to the acute hospital setting.
Patients with allergic alveolitis to various antigens, asymptomatic exposed individuals and healthy control subjects were studied. The lymphocyte transformation test and the formation of two lymphokines were shown to be positive in almost all affected subjects and only rarely in asymptomatic exposed individuals. In most symptomatic subjects and only rarely in asymptomatic exposed individuals. In most symptomatic subjects, the presence of antigen-antibody complexes could be demonstrated. However, such complexes were also present in six of the nine asymptomatic exposed individuals having precipitating antibodies. Factor(s) released from sensitized monocytes strongly facilitate the in vitro formation of specific antibodies but are poorly effective when incubated with cells from asymptomatic exposed subjects or normal individuals.