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Biomedical subjects

M Stella

Publications and source records attributed to M Stella.

At least 73 records · Page 4Linked to original sources
PubMed1992

Comparative study of Langerhans cells in normal and pathological human scars. II. Hypertrophic scars.

Langerhans cells (LCs) seem to play a crucial role in the immune system of the skin. Changes in their density, distribution, phenotype and/or morphology have been described in a number of skin diseases, mostly immunologically mediated. For this reason, we investigated LCs in human hypertrophic scars, since these scars are presently believed to have an immunological basis. A preliminary analysis of the histological features was carried out on vertical serial sections, stained with hematoxylin and eosin. Both epidermal and dermal components of hypertrophic scar biopsies were examined. The total epidermal thickness and the thickness of the single epidermal layers were also measured; the values obtained were similar to those of control skin and normotrophic scars. Subsequently, CDla-positive LCs, revealed by indirect immunofluorescence and immunoperoxidase techniques, were studied to determine their position among the epidermal layers and within the dermis, their dimensions, their density and their morphology. According to these observations, two main types of hypertrophic scars were identified. In the first type (7 scars), LCs were widely clustered within both the whole epidermis and the dermis. Their density was increased (about 750 cells/mm2 of epidermal area), if compared to control skin and normotrophic scars (both about 400 cells/mm2 of epidermal area; p less than 0.001). The epidermal cell profiles, nearly three times larger than those of control skin, exhibited a dense network of interconnected dendrites. Further analysis for the presence of HLA-DR molecules revealed an anomalous expression of these antigens on keratinocytes. In the second type (3 scars), LCs density within the stratum Malpighii was unchanged, relative to control skin and normal scars, while CDla-positive cell bodies remained numerous in basal position and within the subpapillary corion. Epidermal LCs, only slightly larger than those evidentiated in control skin, displayed short and retracted dendritic projections. The aberrant expression of HLA-DR antigens on keratinocytes was very weak and sparse. The present results strongly suggest an immunologically activated state of the tissues examined; they provide morphological data that support the involvement of the immune system in hypertrophic scarring.

Adult↗
PubMed1991

Establishment of a human medulloblastoma cell line (BO-101) demonstrating skeletal muscle differentiation.

A permanent cell line, BO-101, was derived from a classic vermian medulloblastoma in a 9-year-old child. This line grew in vitro in adherent cultures and grew in athymic mice as serially transplantable intracranial and subcutaneous xenografts. Intracranial neoplasms grew as masses of small cells, which focally showed large cells with intense immunoreactivity for desmin, myoglobin and alpha-striated actin. The rhabdomyoblastic nature of these cells was confirmed ultrastructurally. The primary neoplasm showed immunoreactivity for synaptophysin, neuron-specific enolase and vimentin. A large panel of monoclonal antibodies and antisera against neuronal and glial antigens failed to show glial and neuronal immunoreactivity in the cell culture and xenografts. Despite the marked genotypic and phenotypic differences, the original neoplasm and the cell line share a common chromosomal marker del (12) (p 13.1). The BO-101 line differs phenotypically and genotypically from previously established medulloblastoma cell lines and further supports the heterogeneous biologic properties of the cell populations that constitute these neoplasms.

Animals↗
PubMed1991

Immunofluorescence analysis in flow cytometry: better selection of antibody-labeled cells after fluorescence overcompensation in the red channel.

Selection of cells labeled with fluorescein isothiocyanate-conjugated (FITC) antibodies can be difficult if large autofluorescent cells are used and if the cells bind only a few molecules of antibody. We have developed a simple flow cytometric procedure that allows better selection of stained cells. When an argon ion laser emitting at 488 nm is used, the green fluorescence detected is the sum of cell autofluorescence and of the signal generated by the FITC antibody. Thus, when we subtract green signal from the red by fluorescence compensation, the signal of stained cells is on average reduced more than for the unstained counterpart. In this scenario, positive selection of cells with low red signal allows more efficient selection of stained cells. We tested the overcompensation procedure on mixtures of cells unstained and stained with a relevant FITC antibody. Cell mixtures were analyzed using normal vs increased levels of compensation in the red channel. Increased levels of compensation resulted in easier gating and higher recovery of stained cells. The efficiency of the overcompensation procedure was particularly high when using red filters with low cutoff (i.e., 560 or 570 nm), possibly because of the significant emission of fluorescein in the red channel, which caused separation between stained and unstained cells also in the red dimension. This method is useful for sorting cells expressing low levels of surface markers and facilitates selection of rare cells transfected with surface antigen genes. This technique is compatible with the use of propidium iodide for live/dead cell discrimination and with the subtraction of the cellular background of autofluorescence.

Animals↗
PubMed1991

Surgery for colorectal cancer guided by radiodetecting probe. Clinical evaluation using monoclonal antibody B72.3.

Radioactive antibodies that react with tumour-associated antigens to "tag" antigen-positive tumour cell deposits were given to 20 patients with primary or recurrent colorectal cancer. The tumour associated antigen TAG 72-specific monoclonal antibody B72.3 labelled with 125-Iodine was used, and the radioactivity in the tumour was sought during operation with a hand-held gamma detecting probe. Tumour was detected by the probe in 7 of 15 patients with primary cancer, with a mean tumour: normal tissue ratio of 3.9, and in 4 of 5 patients with recurrent disease, with a mean tumour: normal tissue ratio of 2.0. Immunohistochemical analysis of surgical specimens confirmed the results of the intraoperative detection. The incidence of TAG 72-positive tumours (11/20, 55%), detected by immunohistochemistry, was lower than the 80% in the other series, possibly because of sampling errors or because the cases studied were uncomplicated with small primary tumours. Results obtained with the probe were instrumental in modifying the operation in two of the four "positive" patients with recurrences, allowing the removal of tumour masses that would otherwise have been overlooked.

Adenocarcinoma↗
PubMed1991

Effects of an acute protein load on urinary albumin excretion in kidney donors.

In six kidney donors with normal baseline urinary albumin excretion (UAE) we studied the behavior of the UAE after 150 g of a meat protein meal and after a carbohydrate meal of equal caloric (1,370 kcal), water (1 liter) and sodium content (51 mEq). The mean creatinine clearance (Ccr) increased significantly after a protein load at the first (p less than 0.01) and second hour (p less than 0.05), while it did not change after the carbohydrate meal. The mean UAE increased significantly after the protein meal at the first (p less than 0.05) and second hour (p less than 0.05), while after the carbohydrate meal the mean values were increased at the first (p less than 0.05), second (p less than 0.05) and third hour (p less than 0.05). Furthermore, the mean values of UAE after the protein meal were significantly higher (p less than 0.05) than those found at the same time after the carbohydrate meal. Diuresis and natriuresis increased significantly after both meals. These findings show that the increased UAE after the protein meal may be due to a further increase in Ccr in the hyperfiltering remaining kidney, while the smaller increase in the UAE observed after the carbohydrate meal may be due to water load and increased urine flow, which impairs albumin tubular reabsorption. The prognostic importance of microalbuminuria after either meal is therefore uncertain.

Albuminuria↗
PubMed1990

Diagnosis of malignant change in duodenal villous adenoma.

Villous adenomas of the duodenum are rare, and malignancy is discovered in about 30% of the lesions. The authors describe two cases of villous adenoma of the second portion of the duodenum (13 and 8 cm in diameter). The diagnosis was obtained through endoscopy, which did not demonstrate any malignant change. In both patients, malignant change was shown by intraoperative frozen sections, and a pancreatico-duodenectomy was performed. Review of the literature and the authors' experience indicate endoscopic biopsies do not rule out the presence of malignancy in adenomatous pathology of the duodenum. Therefore, laparotomy should be performed whenever endoscopic excision of the neoplasm is not feasible. The authors emphasize the importance of an intraoperative diagnosis based on accurate frozen sections and propose a correct procedure to obtain the best results.

Adenoma↗
PubMed1990

Recurrent chromosomal aberrations in peripheral T-cell lymphoma.

Histological, immunological, and cytogenetic analysis of the same neoplastic tissues have been performed on seven patients with peripheral T-cell lymphomas (PTCL). Clonal chromosomal abnormalities in five cases are reported. The most common chromosomal aberration, observed in four patients, is a rearrangement of chromosome 14 with a breakpoint in q11.2. Aberrations of chromosome 8 also occurred in four patients, three of whom had an extra 8q. The data indicate that breakpoints of malignant diseases affecting similar cell types might cluster to specific chromosomal regions, which can be helpful in recognition and classification of PTCL.

Adult↗
PubMed1990

Procoagulant activity of mononuclear phagocytes from different anatomical sites in patients with gynecological malignancies.

Mononuclear phagocytes exhibit complex interactions with cancer cells and might contribute to fibrin formation associated with malignancy through the production of procoagulant activity (PCA). We have studied the PCA of peritoneal macrophages in 8 patients with advanced (stages III or IV) ovarian cancer and of macrophages from regional lymph nodes in 14 patients with limited (stages I or II) uterine cancer; peritoneal and lymph-node macrophages from patients with benign gynecological tumors were used as reference cell populations. In all patients, PCA of blood monocytes was also studied. Peritoneal and lymph-node macrophages obtained from patients with ovarian and uterine cancer, respectively, expressed far higher levels of basal PCA than the corresponding cell populations from patients with benign tumors (p less than 0.001). PCA of blood mononuclear cells from patients with ovarian, but not with uterine cancer, was significantly higher (p less than 0.001) than that of control cells. High levels of D-dimer, a specific product derived from plasmin-induced degradation of stabilized fibrin, were found in all ascitic fluids and in all plasma samples but one from patients with ovarian cancer. In contrast, all controls and all uterine cancer patients but one had normal plasma D-dimer. Our findings suggest that local activation of host macrophages for PCA production might contribute to fibrin formation within the tumoral mass. In advanced cancer, blood monocytes may also be activated to produce PCA and thus contribute to activation of intravascular coagulation and, possibly, to thrombo-embolic complications frequently associated with disseminated malignancy.

Aged↗
PubMed1990

Establishment and characterization of a primitive neuroectodermal tumor of bone continuous cell line (LAP-35).

A continuous tumor cell line (LAP-35) was established from a primitive neuroectodermal tumor of bone from the right tibia of a 12-year-old female. The neural character of the cell line was documented by the spontaneous growth of neurites and by the presence of several neural markers, including neuron-specific enolase (NSE), S-100 protein, neurofilaments, chromogranin A, synaptophysin and positivity to monoclonal antibodies UJ127.11, UJ13A, UJ181.4. Cell-sorter analysis showed a high expression of nerve growth factor receptor (NGFr) and major histocompatibility complex class I-related molecules. A unique cytogenetic profile was observed, including a reciprocal chromosomal translocation (rct) 11:22 (q24;q12), typically associated with Ewing's sarcoma and neuroepithelioma, and deletion of the short arm of chromosome 1 (lp-), otherwise a feature of neuroblastoma. N-myc proto-oncogene was neither amplified nor expressed, whereas the expression of c-myc was documented by northern blot analysis. These features distinguish this new cell line from previously reported neuroectodermal cell lines, identifying LAP-35 as a unique model of a group of neural bone tumors that share characteristics of neuroblastoma as well as neuroepithelioma.

Animals↗
PubMed1990

The HLA-DR beta 16 allogenotype constitutes a risk factor for hypertrophic scarring.

Nineteen patients that had developed hypertrophic scars subsequent to thermal injury were typed for HLA class II allogenotypes with the restriction fragment length polymorphism technique. A significant association was found with DR beta 16 (pc = 1.45 x 10(-4); relative risk = 12.25). This finding adds evidence to other data suggesting that immunologic phenomena are involved in pathologic scarring. Moreover, the results presented here have allowed an identification of a genetically determined risk factor for hypertrophic scar formation located in the HLA region.

Cicatrix↗
PubMed1990

Xanthogranulomatous cholecystitis. Histopathological study and classification.

Xanthogranulomatous cholecystitis (XC) is a chronic inflammatory lesion of the gallbladder histologically characterized by the presence of varying amounts of foamy histiocytes in the inflammatory infiltrate. In this study a review of 63 cases selected from 1207 surgically removed gallbladder is presented; the percentage found (5.2%) is slightly higher than that of previous reports showing that XC is less uncommon than generally believed. A detailed microscopic study is performed: the authors observed according to the histological features particularly the different patterns of distribution of the inflammatory infiltrate and postulate the existence of three subtypes of XC: multinodular, focal and diffuse XC. Finally, the main etiopathogenetic hypotheses are briefly discussed.

Adult↗
PubMed1990

Anomalous expression of HLA class II molecules on keratinocytes and fibroblasts in hypertrophic scars consequent to thermal injury.

Immunoperoxidase staining of skin sections obtained from 11 hypertrophic scars, six normotrophic scars and three samples of normal skin were performed using anti-HLA monoclonal antibodies (HLA-DR, -DQ, class I), anti-interleukin-2 receptor (IL-2R) and anti-CD1. Sections from all hypertrophic scars showed an anomalous expression of HLA-DR molecules on keratinocytes and fibroblasts. Moreover hypertrophic scars were characterized by dense infiltrates of IL-2R-positive cells and by the presence of abundant Langerhans (CD1+) cells in the epidermis and dermis. These results support the hypothesis that immunologic mechanisms play an important role in hypertrophic scarring and point to an involvement of cell-mediated immune phenomena.

Adolescent↗
PubMed1990

[Correlations between morphometric characteristics and the presence of lymph node metastasis in stage T1 and T2 breast carcinoma].

In this study the relationship between cyto-morphometric characteristics of breast cancer and lymph node status was investigated. The study was conducted on 20 cases of T1-T2 breast cancer with node metastasis and 20 cases of T1-T2 breast cancer without node metastasis. About 100 nuclei for each patient were analyzed by means of a computerized image analyzer, and mean nuclear diameter, mean nuclear area, mean form factor and number of cells in 8 classes of diameter were studied. Mean mitotic index was also calculated. No statistic difference was found for all these variables, between the two groups. In conclusion, cyto-morphometric parameters although often represent an index of aggressiveness, they are not related to lymph node status. This one is, in fact, only an indicator of tumor's ability to spread, and tumor's diffusion can occur through different ways from the lymphatic one.

Breast Neoplasms↗
PubMed1989

Cytogenetic and clinical studies in acute promyelocytic leukemia (M3) and cytologic M3 variant (M3V).

Cytogenetic specimens were obtained from bone marrow 24-hour cultured cells in 22 patients with acute promyelocytic leukemia, including six with microgranular variant. A t(15;17) was identified in 10-100% of metaphase cells from 13 patients. We have found no correlation between complete remission percentage and karyotype. Our data suggest that each laboratory, as far as M3 and M3V are concerned, must study its own culture time as it relates to numerous parameters involving tumoral cell kinetics.

Adolescent↗
PubMed1989

Multicentre experience in the treatment of burns with autologous and allogenic cultured epithelium, fresh or preserved in a frozen state.

This report describes the clinical results obtained from a multicentre experience of the use of autologous and allogenic cultured human epidermal cells in the treatment of partial and full skin thickness burns. A laboratory has been organized to supply cultured epithelium to Burns Units in different cities. From May 1986 to December 1988, 58 patients with an age range of 1 to 59 years, and with burns covering between 7 and 95 per cent of the body surface area, have been treated. Graftable cultured epithelium can be frozen and remain viable if stored in a skin bank. Such grafts were used successfully to treat patients with partial and full skin thickness wounds.

Adolescent↗
PubMed1989

Assessment of HIV-1 screening test sensitivities using serially diluted positive sera can give misleading results.

Three FDA licensed HIV-1 viral lysate and two nonlicensed recombinant antigen assays were used to evaluate six serially diluted plasma samples and 2 highly characterized seroconversion series. The sensitivity as measured by serial dilution did not necessarily correlate with the sensitivity as measured by seroconversion performance with the lysate and the recombinant assays. It is concluded that national licensing agencies should arrange to share seroconversion panels to evaluate accurately the sensitivity of new HIV-1 screening tests.

Diagnostic Errors↗