Biomedical subjects

R Vatti

Publications and source records attributed to R Vatti.

At least 19 recordsLinked to original sources

PubMed2006

IRTA1+ monocytoid B cells in reactive lymphadenitis show a unique topographic distribution and immunophenotype and a peculiar usage and mutational pattern of IgVH genes.

The origin and function of monocytoid B cells (MBCs) are poorly understood. Taking advantage of their strong expression of IRTA1 (a receptor that is also associated with MALT marginal zone B cells), we have comprehensively analysed MBCs in 25 cases of lymphadenitis of different aetiologies, shedding new light on the topographical distribution, immunophenotype and IgV(H) gene usage and mutational profile of this B cell subset. IRTA1(+) MBCs, although predominantly located in the subcapsular and intermediary sinuses, were also observed scattered within germinal centres (GCs) in all lymphadenitis cases examined. The molecular characterization of IgV(H) genes revealed that IRTA1(+) MBCs residing in different areas of the lymph node (subcapsular sinus, intermediary sinuses and GCs) can be clonally related (with intraclonal variation), and that those located in GCs are consistently more mutated and selected for expression of a functional antigen receptor than those located in the sinuses. Moreover, by contrast, IRTA1(+) MBCs in GCs express the memory B cell marker CD27. Finally, in toxoplasmic lymphadenitis, the IRTA1(+) MBC population shows a highly preferential usage of the V(H) genes 3-7 and 3-30 (without any obvious peculiarity in their CDR3s), possibly suggesting that a superantigen expressed by Toxoplasma gondii may be involved in the early activation of this B cell subset.

B-Lymphocyte Subsets↗

PubMed2005

Malignant hypercalcemia in vulvar cancer.

Humoral hypercalcemia of malignancy (HHM) is a common paraneoplastic syndrome, most often associated with squamous cell carcinoma of the lung, esophagus, kidneys and breast, but rarely with vulval cancer. In most patients, HHM is associated with over-production of a peptide analogue of parathormone (parathyroid hormone-related protein, PTHrP). The case of a 70-year-old patient with massive squamous cell epithelioma of the vulva complicated by HHM is reported. To our knowledge, this is the first documented case with high serum concentrations of PTHrP and immunohistochemical confirmation of PTHrP production by neoplastic cells.

Aged↗

PubMed2001

Expression of p185 and p53 in benign and malignant colorectal lesions.

The c-erbB2 gene has been found to be amplified in a number of human adenocarcinomas, leading to elevated levels of expression of its encoded product, p185. Mutations in the p53 gene are also common in colorectal carcinomas, brain tumours, leukaemia and lymphomas. In this study, p185 and p53 overexpression was analyzed in colorectal adenomas (22 tubular adenomas and 2 tubulo-villous adenomas) and moderately differentiated adenocarcinomas (n = 22) in order to determine whether there was a relationship between these two proteins. The proteins are encoded by two genes located in the same chromosome. p185 and p53 expression was determined on tissue sections by immunohistochemical staining procedure. Expression of p185 was significantly higher (p < 0.01) in preneoplastic lesions (95.8% of cases) than colorectal cancer (63.6% of cases). p53 showed an inverse pattern to p185, being expressed in 58.3% of benign lesions and 72.7% of adenocarcinomas. These results confirm that p185 overexpression is associated with the early stages of colorectal cancer, whereas p53 is associated with more advanced stages. Although there was no correlation between p185 and p53 expression in premalignant lesions and adenocarcinomas, these two proteins have an important role in the adenoma-carcinoma sequence.

Adenocarcinoma↗

PubMed2000

Macrophage migration inhibitory factor in prostatic adenocarcinoma: correlation with tumor grading and combination endocrine treatment-related changes.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a ubiquitary cytokine whose expression has been investigated in tumors, showing a correlation between tumor aggressiveness and production of this protein by neoplastic cells. The aim of our study was to correlate MIF expression with tumor grade (Gleason scoring system) and histopathological changes after combined endocrine treatment (CET) of prostate adenocarcinoma. METHODS: We analyzed MIF immunoreactivity in 124 paired needle biopsies and radical prostatectomy specimens from 62 prostate cancer patients, of which 20 had been treated with CET. RESULTS: In untreated prostates, MIF expression significantly correlated with tumor grading, being stronger in low-grade than in high-grade adenocarcinoma. In treated prostates, histopathological changes also correlated with MIF immunoreactivity, but not in a significant manner. CONCLUSIONS: The results of the current study demonstrated that with histological dedifferentiation, prostate adenocarcinoma cells show a reduced MIF expression. This finding may be the consequence of a reduced MIF synthesis or the result of an enhanced and altered secretion by tumor cells into the surrounding stroma. The consequent abnormal interaction between MIF and environmental factors might influence tumor growth and diffusion. On the other hand, the minor but not significantly reduced MIF expression by tumor cells after CET seems to exclude a hormonal regulation of MIF secretion.

Adenocarcinoma↗

PubMed2000

Genetic alterations of the retinoblastoma-related gene RB2/p130 identify different pathogenetic mechanisms in and among Burkitt's lymphoma subtypes.

Alterations of cell cycle-associated genes probably contribute to the pathogenesis of Burkitt's Lymphoma (BL), in addition to c-myc translocation. Mutations disrupting the nuclear localization signal of the retinoblastoma-related gene RB2/p130 have been documented recently in BL cell lines and primary tumors. Given the importance of the RB2/p130 gene in controlling cell growth, mutations of this gene may result in uncontrolled cell proliferation. We tested the expression and genomic organization of the RB2/p130 gene in relation to the proliferative features of a series of BL samples collected from the endemic and sporadic regions, regardless of whether the samples were acquired immune deficiency syndrome (AIDS)-related. The expression of the Rb2/p130, p107, and cell proliferation-related proteins (cyclin A and B) was determined by immunohistochemistry. The structures of exons 19 through 22 of the RB2/p130 gene, encoding for the B domain and C terminus, were analyzed by polymerase chain reaction (PCR) analysis and single-strand conformation polymorphism (SSCP) technique. The direct PCR products were sequenced to identify the actual mutations. Our results suggest that BL is composed of a mixture of molecular types with distinct genetic and phenotypic patterns, probably resulting from different pathogenetic mechanisms. In endemic BL, the RB2/p130 gene is mutated in most of the cases, and the protein is restricted to the cytoplasm. In AIDS-related BL, high levels of nuclear expression of the wild-type pRb2/p130, p107, and cell proliferation-related proteins were detected. This finding is in line with the molecular mechanisms observed in virus-linked oncogenesis. Sporadic BLs were mainly characterized by the low nuclear values of the wild-type pRb2/p130 and, conversely, the high values of p107. The increased cell proliferation due to different alterations of cell growth control by Rb-related proteins may be the first step in lymphomagenesis, during which additional genetic changes, including missense mutations of c-myc, may subsequently occur.

Adolescent↗

PubMed2000

Cyclin D1, B and A expression and cell turnover in psoriatic skin lesions before and after cyclosporin treatment.

BACKGROUND: Cyclosporin induces a dramatic reversal to normality in psoriatic lesions, with a reduction of inflammatory infiltrate and epidermal proliferation. It is known that the cell cycle and cell proliferation are regulated by the sequential activation of cyclin-dependent kinase/cyclin complexes. AIM: We evaluated epidermal cell turnover and thickness, as well as the expression of cyclins D1, B and A in psoriatic skin before and after therapy with cyclosporin. METHODS: Epidermal thickness, mitotic and apoptotic indices (MI, AI), as well as the percentages of epidermal cell nuclei positive for Ki-67 and cyclins D1, B and A were calculated. Cytoplasmic positivity to cyclin B was also evaluated. RESULTS: After 6 weeks of therapy, we observed a clinical improvement of the disease and normalization of the epidermis. Epidermal thickness and Ki-67-, cyclins B- and A-positive nuclei percentage were significantly higher before therapy than after (0.52 +/- 0.05 mm vs. 0.21 +/- 0.03 mm, P < 0.001; 19 vs. 2.6, 19 vs. 3, and 12 vs. 1, respectively; P < 0.0005); cytoplasmic positivity to cyclin B was slightly higher before therapy (score 3 vs. 2-3). Cyclin D1 was negative or expressed in a low percentage of nuclei in psoriasis before therapy (0.78), whereas it was always negative after therapy. MI was 0.15 before therapy, whereas mitoses were almost absent afterwards. Apoptoses were undetectable before therapy, whereas a few apoptoses were observed after treatment (AI = 0.4). CONCLUSIONS: Overexpression of cyclins B and A, rather than D1 seems to characterize psoriasis. Their evaluation could provide further insights in understanding the development of this disorder and could be used to verify the efficacy of currently used therapies as well as future ones.

Adult↗

PubMed2000

Acute thymic involution in fetuses and neonates with chorioamnionitis.

Chorioamnionitis represents the leading cause of preterm birth and related pathologic conditions as well as of fetal death and frequently occurs in symptom-free mothers. Recent radiologic findings have indicated that thymus size is significantly reduced in preterm infants born to mothers with subclinical, histologically proven chorioamnionitis. However, an accurate morphologic description of the thymus gland in fetuses and neonates with chorioamnionitis is lacking, although it is known that infection and other stress processes may cause lymphocyte depletion in the thymuses of infants and older babies (acute stress involution). We describe morphologic modifications in the thymus of fetuses with histologically proven chorioamnionitis and newborn infants with chorioamnionitis and proven sepsis. The main findings included (1) decreased organ volume (ANOVA, P < .0024); (2) reduced corticomedullary ratio (P < 10(-6)); (3) significant changes in the relationship between thymic parenchyma and thymic interstitial tissue with resulting increased organ complexity (P = .03); (4) severe reduction of thymocytes; and (5) other degenerative processes such as monocyte/macrophage infiltration of Hassall's bodies. These results indicate that chorioamnionitis, with or without sepsis, is associated with significant morphologic modifications in the thymus. We wish to note that the described thymic pathology is only one aspect of the fetal systemic inflammatory response syndrome with which chorioamnionitis is associated.

Abortion, Spontaneous↗

PubMed1999

Scarring in papillary carcinoma of the thyroid: report of two new cases with exuberant nodular fasciitis-like stroma.

AIMS: To describe two new cases of papillary carcinoma of the thyroid with exuberant nodular fasciitis-like stroma, one of which was characterized by previously unreported transformation into a poorly differentiated lesion. Moreover, we explore the presence of TGF-beta to help to clarify the pathogenesis of the collagen formation. METHODS AND RESULTS: The case characterized by an aggressive behaviour exhibited areas of transformation into a poorly differentiated (insular) carcinoma of the thyroid. In both cases, as revealed by immunohistochemistry, neoplastic cells produced and secreted high amounts of TGF-beta. On the contrary, TGF-beta immunoreaction was never present in the normal thyroid or in papillary carcinomas without collagen bundles, while a weak, exclusively intracellular reaction was present in a patchy manner in cases showing intratumoral fibrous bundles. CONCLUSIONS: The rare variant of papillary thyroid carcinoma characterized by exuberant stroma may give rise to more aggressive lesions, as do other histotypes of differentiated thyroid carcinomas. TGF-beta, the fundamental cytokine which mediates scarring and activation of myofibroblasts, most probably induces the exuberant stroma.

Adult↗

PubMed1999

Expression of macrophage migration inhibitory factor transcript and protein by first-trimester human trophoblasts.

Macrophage migration inhibitory factor (MIF) was originally identified for its capacity to inhibit the random migration of macrophages in vitro. To date, the role of MIF as a pro-inflammatory cytokine, pituitary hormone, and counter-regulator of glucocorticoid action on the immune response is commonly recognized. Although recent studies suggest an involvement of MIF in reproduction, no data exist on the expression of this cytokine in early human pregnancy. In this study, we evaluated the presence of MIF protein and mRNA in specimens of chorionic villi from first-trimester human placenta. Tissues were obtained at 6-10 wk of gestation and analyzed by Western blotting, reverse transcription-polymerase chain reaction, and immunohistochemistry. Our results demonstrate that human villous tissue is a novel site of MIF synthesis. In addition, immunohistochemical analysis identified MIF protein in the cytotrophoblasts of both the inner layer of villi and in the trophoblastic cell islands. We speculate that in view of its proinflammatory features, MIF might play a critical role in human implantation and in early embryonic development.

Blotting, Western↗

PubMed1998

Different patterns of cell proliferation and death and oncogene expression in cutaneous malignant melanoma.

Ninety-six cutaneous melanomas (CMs) were investigated aiming at finding differences, if any, among the main four clinicopathological types, for Bcl-2, c-myc and p53 protein expression, and for tumor cell proliferation and death indices. Proliferation was assessed by calculating the mitotic index (MI, number of mitoses) and the MIB1 labelling index (M-LI, number of MIB1+ nuclei), and tumor cell death by calculating the apoptotic index (AI, number of apoptoses) among 1000 tumor cells. CMs were subdivided into thin (<1 mm) and intermediate thickness (1-4 mm) tumors. Bcl-2 expression did not significantly change among different types. c-myc Expression decreased especially in thicker superficial spreading (SSM) and lentigo maligna melanoma (LMM) types. p53 Expression was higher in nodular melanoma (NM) and in acral lentiginous melanoma(ALM), which also showed the highest degrees of proliferation. AI was significantly higher in thin rather than in intermediate thickness SSMs, LMMs and ALMs (8.4 vs. 2; 6.1 vs. 2.3, and 5.8 vs. 3.6, respectively). AI was low in thin (1.7) and intermediate thickness (1.9) NMs, which also showed high MI (3.9 and 4.5, respectively), and M-LI (16.7 and 2.9, respectively). Thin and intermediate thickness ALMs also showed high MI and M-LI (4.1 vs. 5.2 and 11.3 vs. 14.6, respectively). Bcl-2 is among genes which inhibit apoptotic death, whereas c-myc and p-53 genes promote this process. In CMs, no relation was found between Bcl-2 expression, MI, PI, and AI. All SSMs, LMMs, and ALMs with a high AI showed a high c-myc expression and were negative for p53. c-myc, Although highly expressed, did not promote a significant apoptotic death in NM type. Bc12, c-myc, and p53 were not equally expressed nor equally related to tumor cell turnover in all CMs, suggesting their different influence on the various types and stages, and the role of other factors in CM growth control.

Cell Death↗

PubMed1997

Cell proliferation, cell death and angiogenesis in early and advanced gastric cancer of intestinal type.

Mitotic (MI) and apoptotic index (AI), the sum of the 2, i.e., the turnover index (TI), tumor neovascularization (NV) and p53 expression, as well as tumor grading and node status, are evaluated in early and advanced gastric-cancer cases. T1 cases show significantly less frequent lymph-node invasion and lower tumor grade, and, taken together, have significantly lower MI, Al and TI and higher values of NV than the T2-3 cases. However, correlation of the variables shows that the above-mentioned discrimination is due to a minority of T1 cases (11 out of 33), while the majority of them are allocated in the same 95% ellipse of tolerance of the T2-3 cases.

Azure Stains↗

PubMed1997

Bronchopulmonary dysplasia of the premature baby: an immunohistochemical study.

Prematurely born infants who required assisted ventilation may develop chronic lung disease or bronchopulmonary dysplasia (BPD). The cells involved in the reparative process of the premature lung are not well defined. The repair of injured tissues is a highly standardized process and the most important cells are activated (modulated) fibroblasts (myofibroblasts). A key cytokine in controlling repair is transforming growth factor-beta (TGF-beta). To characterize the cells involved in the repair process of the premature lung, we employed immunocytochemical techniques and examined the lungs of 39 autopsied premature babies who had neonatal respiratory distress syndrome (RDS). All were treated in neonatal intensive care units and required mechanical ventilation and supplemental oxygen; all survived for at least 12 hours. Antibodies were employed against vimentin, alpha-smooth muscle (alpha-SM) actin, total muscle actin, desmin, MAC387, and TGF-beta. Our study indicates that myofibroblasts are normally present along terminal airways in the developing lung. These cells increase in number some days after lung injury, form bundles of cells encircling terminal air spaces, and acquire desmin contractile filaments shortly thereafter. Myofibroblasts do not lose their contractile filaments with time, suggesting a conversion to smooth muscle metaplasia. The proliferation and migration of such myofibroblasts at sites of lung injury is associated with the presence of TGF-beta. These findings suggest that myofibroblasts play an important role in premature lung repair. They may point the way to experimental and clinical trials that will identify drugs antagonistic to TGF-beta (or other cytokines). Such antagonists may protect the neonates who are at high risk of developing BPD.

Acute Disease↗

PubMed1997

Course of asymptomatic liver involvement in sarcoidosis: role of therapy in selected cases.

AIM: Although granulomatous involvement of the liver with functional abnormalities is widely known, the course of these abnormalities is not clearly known. The study was designed to find out the incidence and course of asymptomatic liver function abnormalities. METHODS: From 1990-1995, during the five year period, 44 (35.2%) of 125 patients with sarcoidosis at LAC + USC Medical Center had liver involvement. Liver enzyme abnormalities aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (AP) were taken as criteria for liver involvement: 41 (93%) patients had elevated AP, 22 (50%) showed elevated ALT, and 24 (54.5%) had elevated AST. RESULTS: 25 of 44 patients received treatment; 12 (48%) showed improvement in liver enzymes and 13 (52%) remained unchanged. Ten (7%) of 13 patients, who did not receive any treatment, also improved. During the same period at USC University Hospital 18 (25%) of 72 had liver involvement. Twelve patients received treatment; 6 (50%) patients showed improvement in liver enzymes. One of 3 patients, who did not receive treatment, improved. 5 (41%) developed complications due to steroids. CONCLUSION: Liver involvement is common in African American patients with sarcoidosis. Social and economic status do not seem to influence the liver involvement. In men the age distribution has an early peak. The outcome of patients who receive treatment remains similar, as far as liver function is concerned, suggesting that most of the patients with liver involvement undergo natural remission. Unless the patient has progressive liver dysfunction, it is advisable to monitor liver enzymes periodically and obtain liver biopsies only if clinically indicated. In patients who need treatment, it is reasonable to try options other than steroids in view of severe corticosteroid related complications.

Adult↗

PubMed1988

Reduction of pinocytotic vesicle surface density in cultured bovine aortic endothelial cells. A quantitative ultrastructural freeze-etching study.

The development of culture techniques for endothelium of the large vessels has stimulated many studies to understand endothelial functions in normal and pathological conditions. In this report we describe that in primary cultures the mean surface density of pinocytotic vesicles, evaluated by computerized morphometric analysis of endothelial cell plasma-membrane, dramatically decreases with respect to that of the cells immediately detached from the arterial wall (6.7 +/- 1.1 microns2 against 19.5 +/- 2.2 microns2, p less than 0.001). The results are unchanged if the cells are enzymatically or mechanically detached from the vessel wall or from the culture flask. After the first passage, the mean surface density of pinocytotic vesicles decreases further (2.5 +/- 1.3 microns2 p less than 0.01). After the 2nd and the 3rd passages, the morphometrical values of endothelial cell plasma-membrane remain low (1.5 +/- 0.2 microns2; 2.5 +/- 0.2 microns2). When endothelial cultures are employed to study pathological aspects of disease, not only the aging process but also the possible occurrence of early changes have to be taken into consideration.

Animals↗

PubMed1986

Co-cultivation of endothelial and smooth muscle cells on opposite sides of a porous membrane.

A co-culture system is here proposed that mimics the topographical situation of the vessel wall in which endothelial cells are separated by a fenestrated elastic lamina from smooth muscle cells. Bovine aortic endothelial cells were grown on one side of a thin microporous membrane and smooth muscle cells were cultivated on the other side. The microporous membrane was inserted in a special frame so that a two-compartment system was created. The membrane may act like the fenestrated internal elastic lamina of arteries in allowing interactions and fluid exchanges between the two cell types through its pores. Membranes were examined both by transmission and scanning electron microscopy to evaluate the morphology of both cell types.

Animals↗

PubMed1984

Morphological aspects in phase-contrast and transmission electron microscopy of senescent cultures of bovine aortic endothelial cells.

Some cultures of bovine aortic endothelial cells underwent an early senescence process, which may have been favoured by a special differential attachment trypsinization procedure. In order to better characterize this phenomenon, the cultures were observed at phase-contrast and electron microscopy at various passages. In phase-contrast microscopy, senescent cells were always larger than "younger" cells, and giant cells were very frequent. A great heterogeneity both of shape and size was present and the cells appeared shrunken, rigid and unable to cover the whole surface of the flask. In many senescent cells long fibres, running from one to the other side of the cytoplasm and often bridging over the nucleus were found. At transmission electron microscopy, together with a great abundance of rough endoplasmic reticulum, mitochondria and lysosomes, and the occasional presence of Weibel-Palade bodies, peripheric bundles of filaments, probably referable to actin or acto-myosin were found. These fibres may be interpreted as "stress fibres" and, as they are expression of a tension not accompanied by an effective cell motility, it seems of interest that they appear in senescent cells, which are often unable to cover the whole surface of flasks by migrating and subsequently proliferating in empty areas.

Animals↗

PubMed1982

[On the growth of cultured bovine aortic endothelial cells. Preliminary observations on ultrastructural morphology by freeze-etching and quantitation of growth rate by phase contrast microscopy: effect of glycosaminoglycans].

Bovine aortic endothelial cells (BAEC), detached from thoracic aorta by collagenase treatment, have been studied after adding a mixture of glycosaminoglycans (GAGs) (the composition of which has been studied by Casu et al. -6), at different concentrations. GAGs at the concentration of 90 mg/100 ml of medium (Dulbecco's modification of Eagle's MEM with 10% foetal calf serum) produced an increase in the growth speed. We have quantitized these data both by counting the number of cells 24 h after trypsinization in phase-contrast-microscopy, and by measuring the time necessary to reach a certain number of influences. Ultrastructural observation at transmission electron microscope after freeze-etching preparation, didn't show any relevant modification either in the organization of cell membrane or in the cytoplasmatic structures. In some observations a conspicuous increase of "vesicular openings" ("pits") on the plasmatic membrane was evident. Statistical evaluation of this phenomenon is under consideration.

Animals↗

PubMed1982

[Effects of high density lipoproteins (HDL) and low density lipoproteins (LDL) on cultured bovine aorta endothelial cells. Preliminary observations on ultrastructural morphology of the plasma membrane by freeze-fracturing].

Bovine aortic endothelial cells (BAEC), detached with collagenase, have been studied morphologically after administration, in vitro, of human lipoprotein fractions (200 micrograms/ml of LDL, 200 micrograms/ml of HDL), 24 h before the confluence. One day after the treated cells and the control one were detached with trypsine and prepared for freeze-etching examination. The plasma-membrane has revealed, in the lipoprotein treated cells (HDL or LDL) an increased average value of the number of "pits" present upon a surface unit (P less than 0,05). Moreover, in the HDL-treated cells, the "pits", sometimes, have appeared with a different morphological evidence, similar to the aspects of exocytosis as seen e.g. in platelets or in Langerhans isle cells.

Animals↗