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Biomedical subjects

A Pinto

Publications and source records attributed to A Pinto.

At least 145 records · Page 8Linked to original sources
PubMed1997

Reed-Sternberg cells of classical Hodgkin's disease react with the plasma cell-specific monoclonal antibody B-B4 and express human syndecan-1.

Although the cellular origin of Reed-Sternberg (RS) cells of classical Hodgkin's disease (HD) has been a controversial issue for many years, recent immunophenotypic and molecular studies have suggested that RS cells of a subset of classical HD cases may be related to B cells. To further define the immunophenotypic features and the differentiation stage of RS cells, a series of 56 HD samples, including both nodular lymphocyte predominance (LP) (eight cases) and classical HD (nodular sclerosis [NS], 32 cases; mixed cellularity [MC], 16 cases) with a non-T-cell phenotype, were evaluated for the immunohistochemical expression of the B-B4 antigen, a specific marker for terminally differentiated B cells. Because the cDNA of the B-B4 antigen encodes syndecan-1, a member of a family of transmembrane heparan sulfate proteoglycans thought to be involved in binding cells of the B lineage to the interstitial matrix, the B-B4 immunoreactivity was correlated with the expression of syndecan-1 in HD-derived cell lines (L428, KM-H2), as detected by both reverse transcriptase polymerase chain reaction (RT-PCR) studies and Western blotting. Our results show that B-B4 reacts with RS cells and their morphological variants of all cases of classical HD, irrespective of their antigenic phenotype (B, undetermined), albeit at a varying degree of cellular expression. Notably, a high reactivity and staining intensity for the B-B4 monoclonal antibody (MoAb) was restricted to tumor cells from NS HD. In cases of the latter subtype, B-B4 positivity was also found in sclerosis-trapped spindle cells (fibrocytes/fibroblasts). Conversely, the putative tumor cells of nodular LP HD were consistently unreactive with the B-B4 MoAb. Finally, we have demonstrated by RT-PCR, flow cytometry, and Western blotting that cultured RS cells, of B and undetermined phenotype, express syndecan-1 mRNA and produce a form of syndecan-1, recognized by the B-B4 MoAb, which is predominantly associated with glycosaminoglycans and is present at the cell surface. Our detection of the plasma cell-specific antigen B-B4 (syndecan-1) on tumor cells of classical HD further supports that RS cell progenitors may be related to germinal/postgerminal center mature B cells and suggests that expression of syndecan-1 may contribute to some of the typical biologic and histopathologic features of classical HD, with a special regard to the NS subtype.

Antibodies, Monoclonal↗
PubMed1997

Expression of the RET receptor tyrosine kinase and GDNFR-alpha in normal and leukemic human hematopoietic cells and stromal cells of the bone marrow microenvironment.

The RET proto-oncogene product is a receptor tyrosine kinase representing the signal-transducing molecule of a multisubunit surface receptor complex for the glial cell line-derived neurotrophic factor (GDNF), in which a novel glycosyl-phosphatidylinositol (PI)-linked protein (termed GDNFR-alpha) acts as the ligand-binding component. We have analyzed expression of RET and GDNFR-alpha in purified normal hematolymphopoietic cells, leukemia/lymphoma cell lines, and 154 primary samples from patients with hematopoietic malignancies encompassing different lineages and differentiation stages. Relatively low amounts of RET mRNA were found in early CD34+ hematopoietic progenitors, but RET transcripts appeared to increase after myelomonocytic maturation. No expression of RET was found in peripheral blood and tissue B and T lymphocytes. Analysis of human myelomonocytic cell lines was overall consistent with results obtained on purified normal cells. Accordingly, RET expression was mainly confined to acute myeloid leukemias (AMLs) displaying either monocytic (French-American-British M4 and M5) or intermediate-mature myeloid (M2 and M3) phenotypes, being less frequently detected in early myeloid (M0 and M1) AMLs. In contrast, RET mRNA was sporadically detected in B-cell tumors, whereas, among T-cell malignancies, RET transcripts were mainly detected in cells of postthymic and mature T-cell phenotype. RET broad detection in primary tumors was not paralleled by the mutual expression of GDNFR-alpha, which was detected only in 2 isolated primary samples and in 3 leukemia/lymphoma cell lines. However, GDNFR-alpha transcripts, in the absence of RET mRNA, were found in normal bone marrow stromal cells (BMSC), in BM fibroblasts, and in two osteoblast cell lines previously described to support normal hematopoiesis. In the presence of GDNF-receptors derived from BMSC by PI-specific phospholipase C cleavage, GDNF efficiently bound RET-expressing AML blasts and was functionally active by reducing their clonogenic growth and triggering the monocytic maturation of leukemic cells.

Adipose Tissue↗
PubMed1997

CD30 ligand is frequently expressed in human hematopoietic malignancies of myeloid and lymphoid origin.

CD30 ligand (CD30L) is a type-II membrane glycoprotein capable of transducing signals leading to either cell death or proliferation through its specific counterstructure CD30. Although several lines of evidence indicate that CD30L plays a key role as a paracrine- or autocrine-acting surface molecule in the deregulated cytokine cascade of Hodgkin's disease, little is known regarding its distribution and biologic significance in other human hematopoietic malignancies. By analyzing tumor cells from 181 patients with RNA studies and immunostaining by the anti-CD30L monoclonal antibody M80, we were able to show that human hematopoietic malignancies of different lineage and maturation stage display a frequent and broad expression of the ligand. CD30L mRNA and surface protein were detected in 60% of acute myeloid leukemias (AMLs), 54% of B-lineage acute lymphoblastic leukemias (ALLs), and in a consistent fraction (68%) of B-cell lymphoproliferative disorders. In this latter group, hairy cell leukemia and high-grade B-cell non-Hodgkin's lymphoma (B-NHL) expressed a higher surface density of CD30L as compared with B-cell chronic lymphocytic leukemia and low-grade B-NHL. Purified plasmacells from a fraction of multiple myeloma patients also displayed CD30L mRNA and protein. A more restricted expression of CD30L was found in T-cell tumors that was mainly confined to neoplasms with an activated peripheral T-cell phenotype, such as T-cell prolymphocytic leukemia, peripheral T-NHL, and adult T-cell leukemia/lymphoma. In contrast, none of the T-lineage ALLs analyzed expressed the ligand. In AML, a high cellular density of CD30L was detected in French-American-British M3, M4, and M5 phenotypes, which are directly associated with the presence on tumor cells of certain surface structures, including the p55 interleukin-2 receptor alpha-chain, the alpha(M) (CD11b) chain of beta2 integrins, and the intercellular adhesion molecule-1 (CD54). Analysis of normal hematopoietic cells evidenced that, in addition to circulating and tonsil B cells, a fraction of bone marrow myeloid precursors, erythroblasts, and subsets of megakaryocytes also express CD30L. Finally, we have shown that native CD30L expressed on primary leukemic cells is functionally active by triggering both mitogenic and antiproliferative signals on CD30+ target cells. As opposed to CD30L, only 10 of 181 primary tumors expressed CD30 mRNA or protein, rendering therefore unlikely a CD30-CD30L autocrine loop in human hematopoietic neoplasms. Taken together, our data indicate that CD30L is widely expressed from early to late stages of human hematopoiesis and suggest a regulatory role for this molecule in the interactions of normal and malignant hematopoietic cells with CD30+ immune effectors and/or microenvironmental accessory cells.

Acute Disease↗
PubMed1997

p53 protein immunoexpression in esophageal squamous cell carcinoma and adjacent epithelium.

BACKGROUND: Immunoreactivity for p53 tumor suppressor gene product is commonly found in human malignancies and some premalignant lesions, but its role in cancer development and its value as a marker of tumor biologic behavior is still unclear. OBJECTIVES: This study was undertaken to assess p53 immunoexpression in esophageal squamous cell carcinoma and attempts to determine its correlation with morphological features associated with tumor behavior. METHODS: Immunohistochemical study was performed on archival paraffin-embedded tissue of 37 esophageal squamous cell carcinomas and respective adjacent mucosa. RESULTS: Twenty-one tumors (56.8%) demonstrated specific staining for p53. Sixteen areas of dysplasia were present in 14 out of the 35 cases. p53 positivity was found in one low-grade dysplasia and in six high-grade dysplasias. By univariate analysis, p53 immunoexpression correlated positively with local invasion (P = 0.01) and perineural spread (P = 0.04). Multivariate analysis with logistic regression showed that tumor invasion was the only factor that discriminated between p53 positive and p53 negative cases (OR: 15.6, P < 0.02). No relationship was found between p53 expression and tumor grade, DNA nuclear ploidy, and S-phase fraction. CONCLUSIONS: These data suggest that p53 dysfunction may be implicated in early, preinvasive, stages of esophageal cancer as well as in the tumor progression related to a more invasive phenotype.

Adult↗
PubMed1997

Undifferentiated rhabdomyosarcoma with lymphoid phenotype expression.

Poorly differentiated rhabdomyosarcomas are traditionally distinguished from lymphomas by their absence of lymphoid markers such as immunoglobulin or CD20 expression. We have encountered three alveolar rhabdomyosarcomas that were initially diagnosed as lymphoid neoplasms because of the expression of a lymphocytic phenotype in morphologically undifferentiated tumor cells. Subsequent cytogenetic analysis revealed a t(2; 13) in two cases. All cases recurred in the chest wall and showed positivity for muscle markers, such as muscle-specific actin, myoglobin, MyoD1, and/or desmin on subsequent immunohistochemistry. The findings in these three cases lead us to conclude that the presence of a lymphoid phenotype does not absolutely exclude the diagnosis of rhabdomyosarcoma.

Adolescent↗
PubMed1997

Molecular epidemiology of an outbreak of Legionnaires' disease associated with a cooling tower in Genova-Sestri Ponente, Italy.

Fatty acid profile analysis, monoclonal antibody (MAb) subtyping, pulsed-field gel electrophoresis (PFGE), arbitrarily primed polymerase chain reaction (AP-PCR), and ribotyping were used to compare clinical and environmental Legionella pneumophila serogroup 1 isolates from an outbreak of Legionnaires' disease presumptively associated with cooling towers. According to the Oxford subtyping scheme, the MAb subtype of patients' isolates and of two strains originating from a cooling tower was Pontiac, whereas the other isolates were subtype Olda. The strains showed no intrinsic strain-to-strain difference in fatty acid profiles, and ribotyping and length polymorphism of the 16S-23S rDNA intervening regions failed to reveal any differences between the isolates. Conversely, PFGE and AP-PCR appeared to be more discriminatory, as the same genomic profile was found for the clinical and some environmental strains. Meteorologic and epidemiological data and the results of molecular analysis of the Legionella pneumophila serogroup 1 isolates support the hypothesis that the infection was transmitted from one of the cooling towers to the indoor environment of the same building, to homes in proximity that had open windows, and to the streets. In fact, the outbreak diminished and later ended after a part in the tower was replaced. This investigation demonstrates the utility of combined molecular methods (i.e., phenotypic and genomic typing) in comparing epidemiologically linked clinical and environmental isolates. Finally, the outbreak confirms the risk of Legionnaires' disease posed by cooling towers, mainly when atmospheric thermal and humidity inversions occur. This finding emphasizes the need to determine whether the source of infection is in the living or working environment or somewhere else.

Adult↗
PubMed1997

Dexamethasone inhibition of acute opioid physical dependence in vitro is reverted by anti-lipocortin-1 and mimicked by anti-type II extracellular PLA2 antibodies.

Dexamethasone has been shown to inhibit opiate withdrawal, in an in vitro model. In this respect, we suggested that dexamethasone could reduce opiate withdrawal by blocking the release of prostaglandins' precursor, arachidonic acid through protein synthesis dependent-mechanisms (1). Since arachidonic acid is released by the enzyme phospholipase A2 (PLA2) in the present paper we evaluate whether dexamethasone effect may by related to inhibition of PLA2 activity. Therefore, the effect of a neutralizing anti-lipocortin-1 antibody and a polyclonal anti-type II extracellular phospholipase A2 antibody on the opiate withdrawal in vitro was considered. Following a 4 min in vitro exposure to morphine a strong contracture of guinea-pig isolated ileum was observed after the addition of naloxone. Dexamethasone at concentration of 5x10(-5) M reduces of 50% morphine withdrawal and the polyclonal anti-type II extracellular PLA2 antibody (in a dilution 1:1000) mimicked dexamethasone inhibitory effect. Incubation of the ileum preparation with a neutralizing anti-lipocortin-1 antibody (at a dilution of 1:10.000) 30 min before dexamethasone reverted the steroid effects. These results suggest that dexamethasone inhibition of opiate withdrawal is due to extracellular type II PLA2 inhibition through lipocortin-1.

Animals↗
PubMed1997

Effect of methylguanidine, guanidine and structurally related compounds on constitutive and inducible nitric oxide synthase activity.

The inhibitory activity of methylguanidine, guanidine and their precursors, creatine and creatinine, on both the neuronal constitutive and lung inducible isoforms of nitric oxide synthase were examined in this study. Methylguanidine and guanidine (0.01-3 mM) significantly (P<0.01) inhibited in a concentration-dependent manner both isoforms of the enzyme. Furthermore analysis of the inhibition curves by ANOVA revealed that methylguanidine and guanidine act as non selective inhibitors of both nitric oxide synthases (P>0.4 for both methylguanidine and guanidine). In contrast, creatine and creatinine, although containing guanidine group, were totally ineffective on either enzyme even at concentration up to 3 mM. The results obtained for tested compounds also suggest a role for the lateral chain of guanidine group in the enzyme inhibition. The lack of selectivity of methylguanidine and guanidine in inhibiting both the nitric oxide synthase enzymes could account for some pathological manifestations like neurological disorders, host defense impairment and probably hypertension, that often occur in patients with uremia or chronic renal failure.

Animals↗
PubMed1997

Analysis of p53 expression in osteosarcoma of the jaw: correlation with clinicopathologic and DNA ploidy findings.

The objective of this study was to determine whether p53 expression correlated with clinicopathological and DNA ploidy in osteosarcoma of the jaw, a particular subtype of osteosarcoma associated with an older age at presentation, longer median survival, rare metastasis, and death due to uncontrolled local recurrence. Seventeen cases of osteosarcoma of the jaw were stained for p53 using CM1 antibody (Novocastra). Eight cases (47.5%) showed nuclear staining in more than 10% of the neoplastic nuclei. Ploidy analysis showed 13 aneuploid (eight p53+) and three diploid (none p53+) tumors. No significant relationship was found between p53 positivity and clinicomorphological features, DNA ploidy or survival. p53-positive cases were, however, more commonly associated with aneuploidy and chondroblastic differentiation. These results indicate that p53 immunostaining does not seem to provide prognostic information in osteosarcoma of the jaw.

Adolescent↗
PubMed1997

Fluoroaluminate induces rapid release of endothelin-1 in the isolated perfused arterial and venous vessels of the rat mesentery.

1. Endothelin-1 (ET-1) production from endothelial cells is generally believed to be a process that happens over the course of hours. 2. When fluoroaluminate (AIF-4) was infused in the isolated perfused arterial and venous vessels of the rat mesentery there was an increase in perfusion pressure on both sides. 3. Treatment of mesentery with the endothelin receptor antagonists FR 139317 (ETA receptor selective) or PD 145065 (ETA-ETB receptor nonselective) caused inhibition on both the arterial and venous sides, suggesting that response is mediated predominantly by endothelin-1 through ETA receptors. 4. Endothelial denudation attenuated changes in perfusion pressure of mesenteric circulation generated by fluoroaluminate, but not those caused by exogenously added PGF2 alpha. 5. Our data demonstrate that there is an immediate release of endothelin-1 following fluoroaluminate infusion which could be partially mediated by activation of phospholipase C.

Aluminum↗
PubMed1997

Mitochondrial abnormalities of liver in two children with citrullinaemia.

Citrullinaemia is a rare inborn error of urea-cycle metabolism. Two affected children are reported in whom progressive metabolic instability suggested the possibility of hepatopathy or an ongoing hepatic mitochondrial injury. A percutaneous liver biopsy was performed in each patient. Electron-microscopic findings were similar in both cases. Approximately 20% of the mitochondria were abnormally enlarged with paracrystalline inclusions and electron-dense bodies of different sizes and shapes present in the matrix. The specificity of these findings is discussed in the context of previous reports of ultrastructural abnormalities in the hepatocytes of patients with inborn errors of the urea cycle. It is speculated that the mitochondrial abnormalities in citrullinaemia may be related to the accumulation of citrulline in the mitochondria which may eventually manifest as metabolic instability.

Cell Nucleus↗
PubMed1997

Gasless laparoscopic treatment of perforated duodenal ulcer: a case report.

Ruptured duodenal peptic ulcer is a serious complication of ulcer disease that occurs in approximately 5% of cases. Its emergency treatment is based on surgery, namely, simple closure or more definitive ulcer surgery. Laparoscopic repair of perforated duodenal ulcer with classic insufflation of CO2 is quick, simple, and technically feasible in most patients. We describe herein the operative treatment of a perforated duodenal ulcer in a 33-year-old man who presented to our Hospital with acute onset of severe abdominal pain. Wide peritoneal lavage and suture of the perforation was performed by gasless laparoscopic technique using a mechanical retractor obviating the creation of the pneumoperitoneum and of the sealed environment. This new approach enables the use of conventional instruments and provides a clear field of vision in the abdomen equal to that created by the traditional CO2 technique. Because there is not a pneumoperitoneum to maintain, the gasless technique permits a constant irrigation and suction of the abdominal cavity, a wide peritoneal lavage, and the continuous suction of fluid, blood, smoke, and humidity without losing the camera set. If indicated, it permits the laparoscopic repair of the perforation combined with the laparoscopic vagotomy in the same emergency setting. The present case proved it to be another abdominal procedure that can be carried out with all the technical and anesthesiological advantages of gasless minimally invasive surgery.

Acute Disease↗
PubMed1997

Spectrophotometric detection of RT-PCR-amplified BCR/ABL fusion transcripts. A survey performed on archival hematologic slides.

We describe a method of spectrophotometric detection of BCR/ABL chimeric sequences amplified by multiplex reverse transcriptase-polymerase chain reaction (RT-PCR), enabling the use of archival hematologic slides as RNA sources. Multiplex PCR amplified b3a2, b2a2, and e1a2 break points of the BCR/ABL translocation and the normal ABL gene product. Assessment of sensitivity, performed on K562 cells, showed that the threshold approximated radioactive methods of detection (i.e., 1 positive cell in 1 x 10(6) negative cells for single round PCR and lower than 1 positive cell in 1 x 10(7) negative cells for nested PCR). Then, we assayed 38 different archival hematologic slides from 18 patients, including 11 cases of chronic myelogenous leukemia or chronic myelogenous leukemia-like disease, such as a case of myelofibrosis and a case of chronic neutrophilic leukemia, 6 cases of acute lymphoblastic leukemia, and 1 case of acute myelogenous leukemia. Amplification and spectrophotometric detection of BCR/ABL fusion messenger RNAs gave an unambiguous positive result in 24 (89%) of 27 expected positive slides, among which 17 (63%) were positive after a single PCR round. Concordant unambiguous results were obtained from 35 (92%) of 38 slides, as verified through parallel analyses of corresponding cryopreserved cells. Retrospective analysis on archival hematologic slides yielded identification of the presence or absence of the t(9;22) translocation and break point in 14 previously uncharacterized cases. The application of this method can help define the diagnosis of cases lacking other appropriate material and assist in the retrospective analysis of large patient series for which only smears are available.

Cell Line↗
PubMed1997

Apoptosis in proliferative glomerulonephritis: decreased apoptosis expression in lupus nephritis.

BACKGROUND: Apoptosis is a mechanism of cellular death involved in the deletion of cells in hyperplasic processes which has been observed in proliferative glomerulonephritis. Patients with systemic lupus erythematosus (SLE) are known to have defective apoptosis but there is scarce information about apoptosis in the renal lesions of this disease. The present studies were done to evaluate apoptosis in relation to the intensity of proliferation in several glomerulonephritis and the possible association between this relationship and the chronic histologic changes in lupus nephritis. METHODS: Studies were done in renal biopsies from 19 patients with lupus nephritis (types, IV, Va, Vb) classified with respect to chronicity and activity indexes, five patients with acute poststreptococcal glomerulonephritis, five with idiopathic mesangioproliferative glomerulonephritis, four with membranous glomerulonephritis, four with minimal-change nephrotic syndrome, and three patients with focal segmental sclerosis. Seven normal kidneys which could not be used for transplantation were used as a control group. Apoptosis was determined by in situ DNA nick-end labelling techniques and proliferating cells were identified with a monoclonal antibody antiproliferating cell nuclear antigen (PCNA). RESULTS: Decreased number of apoptotic cells and a high ratio of PCNA: apoptosis were observed in glomerulus and tubulointerstitium of patients with lupus nephritis when compared to other proliferative glomerulonephritis and controls. In lupus nephritis, glomerular apoptosis had a negative correlation with the chronicity index (r = -0.606 P = 0.005). The number of apoptotic cells in the glomeruli was not correlated with the number of PCNA positive cells in lupus nephritis, in contrast with a striking linear correlation observed in acute poststreptococcal nephritis (r = 0.925, P = 0.024), a disease with excellent prognosis. CONCLUSIONS: Apoptosis is decreased in proliferative lupus nephritis. Intense proliferation without increment in apoptosis (a high PCNA: apoptosis ratio) is a characteristic of lupus nephritis associated with chronic renal histological changes.

Adolescent↗
PubMed1997

The increase in blood pressure induced by inhibition of nitric oxide synthase in anesthetized Wistar rats is inversely related to basal blood pressure value.

Nitric oxide produced by endothelial cells is a mediator involved in the regulation of vascular tone. Indeed, in vitro inhibition of basal nitric oxide release increase responses to vasoconstrictor agents, and in vivo, the parenteral or dietary administration of nitric oxide inhibitors produces an increase in blood pressure. However, the correlation of nitric oxide production and basal blood pressure in normotensive subjects is still unclear. In this study, we showed that administration, in urethane-anesthetized Wistar rat, of two inhibitors of nitric oxide synthase, such as NG-nitro-L-arginine methyl ester and methylguanidine, produced a significant increase in mean arterial blood pressure that was inversely related to basal mean arterial blood pressure at all doses tested. On the other hand, the increase in mean arterial blood pressure induced by infusion of angiotensin II did not correlate with basal mean arterial blood pressure. The pretreatment of rats with hexamethonium did not change the results observed in normal rats, ruling out an involvement of sympathetic nervous system. In conclusion, this study further confirms the presence of a tonic amount of nitric oxide, produced by endothelial cells in the bloodstream, which plays a key role in the regulation of basal blood pressure, and its reduction or inhibition may be the main cause of certain pathologic conditions characterized by high levels of blood pressure.

Aging↗
PubMed1997

Serologic survey for antibodies to Borrelia burgdorferi in sheep, goats and dogs in Cordillera Province, Bolivia.

A serosurvey for antibodies to Borrelia burgdorferi using an enzyme-linked immunosorbent assay (ELISA) was conducted on sheep, goat and dog serum samples collected in Cordillera Province, Bolivia, in 1992 Sera from 98 sheep, 218 goats and 43 dogs were tested. The observed seroprevalence in sheep and dogs was 0.0%, whereas the seropositivity rate for goat serum samples was 5.0%. Upon analysing 10 positive sera by Western immunoblotting, five reacted against the specific protein antigens and all of them met the criteria for positivity on the basis of immunoglobulin G (IgG) bands, indicating that goats in Cordillera Province were exposed to B. burgdorferi. These findings, which are further proof of the existence of B. burgdorferi infection in Bolivia, indicate the serologic analysis of goats as a suitable tool for Lyme borreliosis surveillance.

Animals↗
PubMed1997

Sulodexide versus calcium heparin in the medium-term treatment of deep vein thrombosis of the lower limbs.

Thirty adult patients with distal, monolateral deep vein thrombosis of the lower limbs were randomly treated for sixty days either with subcutaneous Ca-Heparin or with Sulodexide, administered IM for ten days and orally for fifty days. The thrombus accretion above the knee, the venous pressures of the affected leg, the clinical symptomatology, and some laboratory coagulative tests were monitored throughout the administration period. Local tolerability of the two treatments was also evaluated. The two applied treatments evidenced a net antithrombotic activity, preventing thrombus accretion above the knee, improving with the same efficacy the venous pressures in the affected legs, and similarly reducing clinical symptoms, with a quick and statistically significant trend toward normalization. Blood fibrinogen was significantly lowered by both drugs, while only Ca-heparin yielded a prolongation of activated partial thromboplastin time. Local tolerability of treatments was better for the mainly oral Sulodexide administrations, while subcutaneous Ca-heparin often induced small, though transient, hematomas.

Adult↗