Alda Wakamatsu

Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, San Paulo, São Paulo, Brazil

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Publications (52)70.31 Total impact

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    ABSTRACT: ObjectiveLIN28 control cells reprogramming and pluripotency mainly through miRNA regulation and has been overexpressed in many advanced cancers. In this study, we evaluated the prognostic role of LIN28 and its regulatory miRNAs in a large cohort of adrenocortical tumors (ACTs).Patients and methodsLIN28 protein expression was assessed in 266 adults ACTs (78 adenomas and 188 carcinomas) from Brazil and Germany. LIN28A and LIN28B gene expression was analyzed in 59 ACTs (31 adenomas and 28 carcinomas) and copy number variation in 39 ACTs. In addition, we determined the expression of let-7 family, mir-9, mir-30 and mir-125 in 28 carcinomas.ResultsLIN28A gene was overexpressed in aggressive ACCs when compared with adenomas and non-aggressive ACCs, but no LIN28A copy number variation was found in ACTs. Unexpectedly, weak LIN28 protein expression was significantly associated with reduced disease-free survival in ACC patients (p= 0.01), but for overall survival only a trend was detectable (p= 0.117). In the multivariate analysis, only Ki67 index ≥ 10% (HR 4.6, p= 0.000) and weak LIN28 protein expression (HR 2.0, p= 0.03) were independent predictors of recurrence in ACC patients. Interestingly, mir-9 expression, a negative LIN28A/B regulator, was significantly higher in aggressive than in non-aggressive ACCs [2076 (from 36 to 9307) vs. 133.4 (from 2.4 to 5193); p= 0.011] and was highly associated with reduced overall (p= 0.01) and disease-free survival (p= 0.01). However, mir-9 prognostic role should be further evaluated in a larger cohort.Conclusion Weak LIN28 protein expression was associated with recurrence in ACCs. Additionally, overexpression of mir-9, a negative LIN28A regulator, was associated with poor outcome.This article is protected by copyright. All rights reserved.
    Clinical Endocrinology 09/2014; · 3.40 Impact Factor
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    ABSTRACT: Glioblastoma (GBM), the most frequent and aggressive brain tumor, is characterized by marked angiogenesis directly related to invasiveness and poor prognosis. Hypoxia is considered to be an important stimulus for angiogenesis by inducing hypoxia-inducible factor 1-alpha (HIF-1α) overexpression that activates platelet-derived growth factor (PDGF) and VEGF. The aim of this study is to analyze the expression of PDGF-C, VEGF in endothelial and tumor cells of GBM and their relation to HIF-1α expression. Two hundred and eight GBM cases were studied by tissue microarray immunohistochemical preparation. Expression of HIF-1α, VEGF and PDGF-C was observed in 184 (88.5%), 131 (63%) and 160 (76.9%) tumor cases, respectively. The numbers of vessels were quantified by CD34, PDGF-C, VEGF and CD105 staining, and were in median 20, 16, 5 and 6, respectively. The GBMs that showed positive or negative expression for HIF-1α showed a median vascular density of 30 and 14, respectively, for CD34 (P < 0.015). Positive expression for HIF-1α was correlated with VEGF and PDGF-C expression in tumors (P < 0.001). There was a significant correlation between VEGF and PDGF-C expression in the cytoplasm of GBM tumor cells (P < 0.0001). We showed that VEGF expression in tumor cells was correlated with its expression in blood vessels (P < 0.0001). Endothelial cells with PDGF-C and VEGF positive expression were also positive for CD105 and their nuclei for Ki-67, confirming the neoangiogenic and proliferative influence of VEGF and PDGF-C. VEGF nuclear staining in tumor cells (P = 0.002) as well as nuclear staining for HIF-1α and VEGF (P = 0.005) correlated with survival. In summary, our present findings of the concomitant upregulation of PDGF-C with VEGF in GBM tumor cells and vessels further reinforce the benefit of using combined anti-angiogenic approaches to potentially improve the therapeutic response for GBM.
    Neuropathology 02/2014; · 1.91 Impact Factor
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    ABSTRACT: ABSTRACT Introduction: EGFR analyses allow for better correlation between genotype and phenotype in astrocytomas and represent an attractive therapeutic target. Most studies emphasize analyses of EGFR in glioblastomas (GBMs) but do not analyze all grades of astrocytomas (from pilocytic to GBM). The purpose of our study was to evaluate the status of EGFR (expression, deletion, and amplification) and EGFR protein expression in all grades of astrocytomas. Patients and methods: We analyzed a total of 145 surgical tumor specimens that included: 22 pilocytic astrocytomas, 22 grade II astrocytomas, 17 grade III astrocytomas and 84 GBMs. The specimens were compared to 17 non-neoplastic brain tissues obtained from epilepsy surgery. EGFR expression, EGFR amplification and EGFRvIII analyses were performed by quantitative real-time PCR, and protein expression was evaluated by immunohistochemistry. Results: EGFR relative overexpression and EGFR amplification were observed, respectively, in 50% and 20% of astrocytomas, while EGFRvIII was only found in GBMs (34.5%, p=0.005). Amongst EGFR -amplified GBM cases, 59% also presented EGFRvIII (p<0.001). Cytoplasmic accumulation of EGFR protein was detected in 75% of astrocytomas, and 21% of the astrocytomas showed nuclear localization (p=0.003). Conclusions: EGFR alterations were found in all grades of astrocytomas, from pilocytic to GBMs, while EGFRvIII was exclusively found in GBMs. These findings provide important information on the mechanisms involved in the progression of astrocytomas for determining whether EGFR status can be used for effective and specific therapy.
    The International journal of biological markers 09/2013; · 1.59 Impact Factor
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    International Journal of Morphology 06/2013; 31(2):747-753. · 0.21 Impact Factor
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    ABSTRACT: Objectives: The aims of the present study were to determine: 1) the fiber-type and fiber cross sectional area distribution in masseter and temporal muscles through the aging process, in both genders, 2) the proportion of hybrid and neonatal fibers, and their capillary density along the nine decades of life, and 3) the correlation of these parameters with the masticatory function, i.e., the bite force. Methods: We studied the differences of the fiber types in masseter and temporalis muscles along the first to ninth decades in both genders. Seventy-four (74) samples were analyzed by immunohistochemistry. Results: Slow and fast muscle fiber distribution was similar in both muscles in both genders. Hybrid fiber was observed in all decades, and its frequency decreased significantly (p<0.001) with aging in masseter. Neonatal myosin expression was observed in all decades; its expression was more frequent in masseter (p=0.01), and males in temporalis (p=0.025). Decrease of the cross-sectional area of fast and slow fibers and decrease in capillary density were detected with aging. These morpho-immunohistochemical alterations in masseter and temporalis muscles correlated with the decrease in bite force with aging. Conclusions: This muscles are essential components in the stomatognatic system. Their complex architecture allows them to execute several motor tasks. The jaw muscles proved to be highly unusual compared to limb and trunk muscles. Masseter and temporalis muscles contain many hybrid fibers, which numbers decrease with aging, and numerous neonatal fibers in the majority of samples over nine decades of age. We also observed a decreased in the capillary density and of the cross sectional area; together, all findings can be related to the decrease in bite force with aging.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: We investigated four components of the Wnt signaling pathway in medulloblastomas. Medulloblastoma is the most common type of malignant pediatric brain tumor, and the Wnt signaling pathway has been shown to be activated in this type of tumor. Sixty-one medulloblastoma cases were analyzed for β-catenin gene (CTNNB1) mutations, β-catenin protein expression via immunostaining and Wnt signaling pathway-related gene expression. All data were correlated with histological subtypes and patient clinical information. CTNNB1 sequencing analysis revealed that 11 out of 61 medulloblastomas harbored missense mutations in residues 32, 33, 34 and 37, which are located in exon 3. These mutations alter the glycogen synthase kinase-3β phosphorylation sites, which participate in β-catenin degradation. No significant differences were observed between mutation status and histological medulloblastoma type, patient age and overall or progression-free survival times. Nuclear β-catenin accumulation, which was observed in 27.9% of the cases, was not associated with the histological type, CTNNB1 mutation status or tumor cell dissemination. The relative expression levels of genes that code for proteins involved in the Wnt signaling pathway (CTNNB1, APC, AXIN1 and WNT1) were also analyzed, but no significant correlations were found. In addition, large-cell variant medulloblastomas presented lower relative CTNNB1 expression as compared to the other tumor variants. A small subset of medulloblastomas carry CTNNB1 mutations with consequent nuclear accumulation of β-catenin. The Wnt signaling pathway plays a role in classic, desmoplastic and extensive nodularity medulloblastoma variants but not in large-cell medulloblastomas.
    Clinics (São Paulo, Brazil) 02/2013; 68(2):167-72. · 1.59 Impact Factor
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    ABSTRACT: Ovarian adenocarcinoma is frequently detected at the late stage, when therapy efficacy is limited and death occurs in up to 50% of the cases. A potential novel treatment for this disease is a monoclonal antibody that recognizes phosphate transporter sodium-dependent phosphate transporter protein 2b (NaPi2b). To better understand the expression of this protein in different histologic types of ovarian carcinomas, we immunostained 50 tumor samples with anti-NaPi2b monoclonal antibody MX35 and, in parallel, we assessed the expression of the gene encoding NaPi2b (SCL34A2) by in silico analysis of microarray data. Both approaches detected higher expression of NaPi2b (SCL34A2) in ovarian carcinoma than in normal tissue. Moreover, a comprehensive analysis indicates that SCL34A2 is the only gene of the several phosphate transporters genes whose expression differentiates normal from carcinoma samples, suggesting it might exert a major role in ovarian carcinomas. Immunohistochemical and mRNA expression data have also shown that 2 histologic subtypes of ovarian carcinoma express particularly high levels of NaPi2b: serous and clear cell adenocarcinomas. Serous adenocarcinomas are the most frequent, contrasting with clear cell carcinomas, rare, and with worse prognosis. This identification of subgroups of patients expressing NaPi2b may be important in selecting cohorts who most likely should be included in future clinical trials, as a recently generated humanized version of MX35 has been developed.
    Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry 03/2012; 20(2):165-72. · 1.63 Impact Factor
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    ABSTRACT: Up-regulation of S100A7 (Psoriasin), a small calcium-binding protein, is associated with the development of several types of carcinomas, but its function and possibility to serve as a diagnostic or prognostic marker have not been fully defined. In order to prepare antibodies to the protein for immunohistochemical studies we produced the recombinant S100A7 protein in E. coli. mRNA extracted from human tracheal tumor tissue which was amplified by RT-PCR to provide the region coding for the S100A7 gene. The amplified fragment was cloned in the vector pCR2.1-TOPO and sub-cloned in the expression vector pAE. The protein rS100A7 (His-tag) was expressed in E. coli BL21::DE3, purified by affinity chromatography on an Ni-NTA column, recovered in the 2.0 to 3.5 mg/mL range in culture medium, and used to produce a rabbit polyclonal antibody anti-rS100A7 protein. The profile of this polyclonal antibody was evaluated in a tissue microarray. The rS100A7 (His-tag) protein was homogeneous by SDS-PAGE and mass spectrometry and was used to produce an anti-recombinant S100A7 (His-tag) rabbit serum (polyclonal antibody anti-rS100A7). The molecular weight of rS100A7 (His-tag) protein determined by linear MALDI-TOF-MS was 12,655.91 Da. The theoretical mass calculated for the nonapeptide attached to the amino terminus is 12,653.26 Da (delta 2.65 Da). Immunostaining with the polyclonal anti-rS100A7 protein generated showed reactivity with little or no background staining in head and neck squamous cell carcinoma cells, detecting S100A7 both in nucleus and cytoplasm. Lower levels of S100A7 were detected in non-neoplastic tissue. The polyclonal anti-rS100A7 antibody generated here yielded a good signal-to-noise contrast and should be useful for immunohistochemical detection of S100A7 protein. Its potential use for other epithelial lesions besides human larynx squamous cell carcinoma and non-neoplastic larynx should be explored in future.
    BMC Research Notes 11/2011; 4:494.
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    ABSTRACT: Limb-girdle muscular dystrophy presents with heterogeneous clinical and molecular features. The primary characteristic of this disorder is proximal muscular weakness with variable age of onset, speed of progression, and intensity of symptoms. Sarcoglycanopathies, which are a subgroup of the limb-girdle muscular dystrophies, are caused by mutations in sarcoglycan genes. Mutations in these genes cause secondary deficiencies in other proteins, due to the instability of the dystrophin-glycoprotein complex. Therefore, determining the etiology of a given sarcoglycanopathy requires costly and occasionally inaccessible molecular methods. The aim of this study was to identify phenotypic differences among limb-girdle muscular dystrophy patients who were grouped according to the immunohistochemical phenotypes for the four sarcoglycans. To identify phenotypic differences among patients with different types of sarcoglycanopathies, a questionnaire was used and the muscle strength and range of motion of nine joints in 45 patients recruited from the Department of Neurology--HC-FMUSP (Clinics Hospital of the Faculty of Medicine of the University of São Paulo) were evaluated. The findings obtained from these analyses were compared with the results of the immunohistochemical findings. The patients were divided into the following groups based on the immunohistochemical findings: α-sarcoglycanopathies (16 patients), β-sarcoglycanopathies (1 patient), γ-sarcoglycanopathies (5 patients), and nonsarcoglycanopathies (23 patients). The muscle strength analysis revealed significant differences for both upper and lower limb muscles, particularly the shoulder and hip muscles, as expected. No pattern of joint contractures was found among the four groups analyzed, even within the same family. However, a high frequency of tiptoe gait was observed in patients with α-sarcoglycanopathies, while calf pseudo-hypertrophy was most common in patients with non-sarcoglycanopathies. The α-sarcoglycanopathy patients presented with more severe muscle weakness than did γ-sarcoglycanopathy patients. The clinical differences observed in this study, which were associated with the immunohistochemical findings, may help to prioritize the mutational investigation of sarcoglycan genes.
    Clinics (São Paulo, Brazil) 01/2011; 66(10):1713-9. · 1.59 Impact Factor
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    ABSTRACT: Study background: Cathepsins are lysosomal cysteine proteases that have increased expression in tumor cells, may translocate to the cell surface and be secreted. They play a role in tumor angiogenesis. Cystatins are natural cysteine protease inhibitors that can inhibit tumor development, growth and metastasis. In the present work we evaluated the potential therapeutic use of sugarcane cystatin CaneCPI-4 as an anticancer drug. Methods: Viability, migration, invasion and anchorage-independent growth were investigated in B16F10-Nex2 melanoma and HUVEC cells in the presence of CaneCPI-4. The in vivo effect of CanceCPI-4 on tumor development was assessed using a murine model. Angiogenesis in vitro was evaluated using HUVEC cells plated on Matrigel. Immunohistochemical analysis of CD34 expression in primary melanoma was also carried out. Results: Sugarcane cystatin CaneCPI-4 was not cytotoxic to melanoma or HUVEC cells growing in vitro, but efficiently inhibited melanoma cell development in vivo. CaneCPI-4 inhibited melanoma and endothelial cell migration and tumor invasion in vitro. Using a Matrigel angiogenesis assay, CaneCPI-4 at 1 mM was able to completely abolished endothelial cell sprouting in vitro. Angiogenesis inhibition was confirmed in vivo by immunohistochemistry. Conclusions: Sugarcane cystatin CaneCPI-4 inhibits melanoma development in vivo by angiogenesis disruption and inhibition of melanoma invasion, migration and anchorage-independent growth.
    Journal of Cancer Science and Therapy 01/2011; 3(7):161.
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    ABSTRACT: Non-alcoholic fatty liver disease (NAFLD) encompasses the whole spectrum of steatosis, non-alcoholic steatohepatitis (NASH), and NASH-related cirrhosis (NASH/Cir). Although molecular advances have been made in this field, the pathogenesis of NAFLD is not completely understood. The gene expression profiling associated to NASH/Cir was assessed, in an attempt to better characterize the pathways involved in its etiopathogenesis. Methods: In the first step, we used cDNA microarray to evaluate the gene expression profiles in normal liver (n=3) and NASH/Cir samples (n=3) by GeneSifter analysis to identify differentially expressed genes and biological pathways. Second, tissue microarray was used to determine immunohistochemical expression of phosphorylated mTOR and 4E-BP1 in 11 normal liver samples, 10 NASH/Cir samples and in 37 samples of cirrhosis of other etiologies to further explore the involvement of the mTOR pathway evidenced by the gene expression analysis. Results: 138 and 106 genes were, respectively, up and down regulated in NASH/Cir in comparison to normal liver. Among the 9 pathways identified as significantly modulated in NASH/Cir, the participation of the mTOR pathway was confirmed, since expression of cytoplasmic and membrane phospho-mTOR were higher in NASH/Cir in comparison to cirrhosis of other etiologies and to normal liver. Conclusions: Recent findings have suggested a role for the cellular "nutrient sensor" mTOR in NAFLD and the present study corroborates the participation of this pathway in NASH/Cir. Phospho-mTOR evaluation might be of clinical utility as a potential marker for identification of NASH/Cir in cases mistakenly considered as cryptogenic cirrhosis owing to paucity of clinical data.
    Histology and histopathology 09/2010; 25(9):1123-31. · 2.28 Impact Factor
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    ABSTRACT: Background: Steroidogenic factor 1 (SF-1) is a key determinant of endocrine development and function of adrenal cortex. SF-1 overexpression and gene amplification were previously demonstrated in a small group of pediatric adrenocortical tumors. Objective: Our objective was to determine the frequency of SF-1 protein expression and gene amplification in a large cohort of pediatric and adult adrenocortical tumors. Patients: SF-1 protein expression was assessed in a cohort of 103 adrenocortical tumors from 36 children and 67 adults, whereas gene amplification was studied in 38 adrenocortical tumors (17 from children). Methods: Tissue microarray, multiplex ligation-dependent probe amplification, and quantitative real-time PCR were used. Results: A strong nuclear SF-1 expression was detected by tissue microarray in 56% (20 of 36) and 19% (13 of 67) of the pediatric and adult adrenocortical tumors, respectively (P = 0.0004). Increased SF-1 copy number was identified in 47% (eight of 17) and 10% (two of 21) of the pediatric and adult adrenocortical tumors, respectively (P = 0.02). All adrenocortical tumors with SF-1 gene amplification showed a strong SF-1 staining, whereas most of the tumors (61%) without SF-1 amplification displayed a weak or negative staining (P = 0.0008). Interestingly, a strong SF-1 staining was identified in five (29%) pediatric adrenocortical tumors without SF-1 amplification. The frequency of SF-1 overexpression and gene amplification was similar in adrenocortical adenomas and carcinomas. Conclusion: We demonstrated a higher frequency of SF-1 overexpression and gene amplification in pediatric than in adult adrenocortical tumors, suggesting an important role of SF-1 in pediatric adrenocortical tumorigenesis.
    The Journal of Clinical Endocrinology and Metabolism 03/2010; 95(3):1458-62. · 6.31 Impact Factor
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    ABSTRACT: Thyroid cancer is the most frequent endocrine neoplasia worldwide. The route for metastasis and loco-regional invasion preferentially occurs by lymphatic vessels. For this reason, the assessment of lymphatic vessel density (LVD) is supposed to represent both a prognostic parameter and also a potential therapeutic target. In order to evaluate the value of LVD in benign and malignant thyroid lesions, we analyzed 110 thyroidectomy specimens using D2-40, a specific marker for lymphatic vessels and vascular endothelial growth factor C (VEGF-C), the most potent molecule of lymphatic proliferation. LVD was significantly different between papillary and follicular carcinomas in total (p = 0.045) and peritumoral area (p = 0.042). Follicular adenoma and follicular carcinoma showed an important difference of intra- (p = 0.019) and peritumoral (p = 0.033) LVD. VEGF-C was more markedly expressed in malignancies than in benign lesions (p = 0.0001). Almost all cancers with high positive VEGF-C expression also exhibited increased peritumoral LVD (p = 0.049) when compared with the benign lesions. Indeed, the high peritumoral LVD of malignant thyroid lesions is an important finding for surgery planning and supports the practice of total thyroidectomy in malignant thyroid neoplasm's since the lymphatic peritumoral vessels definitely are an escape path for tumor cells.
    Endocrine Pathology 03/2010; 21(2):101-7. · 1.60 Impact Factor
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    ABSTRACT: Pituitary tumors can be morphologically classified as microadenomas (diameter<1 cm) or macroadenomas (>1 cm), which can be enclosed, invasive and/or expansive. Functionally, they are classified as secreting tumors and clinically non-secreting or 'non-functioning' tumors. Several molecular mechanisms have been studied acting in uncontrolled cell proliferation and the acquisition of resistance to apoptosis. A potential mechanism related to apoptosis control has been found following the isolation and characterization of the ASPP proteins family. All these proteins share sequence similarities in their C-termini, which contains their signature sequences of Ankyrin repeats, SH3 domain and proline-rich region. Recent investigations reported that the expression of iASPP mRNA and protein was increased in non-transformed cells induced to undergo apoptosis and inhibition of iASPP expression in these cells by siRNA reduced apoptosis. Thus, modulation of iASPP expression seems to be an integral part of the apoptotic response. The ASPP proteins family binds to proteins that are key players in controlling apoptosis (P53 and NFkappaB p65 subunit). It has been speculated that the iASPP protein product induces apoptosis by blocking NFkappaB or inhibits apoptosis by blocking P53. By either mechanism, the gene could influence the survival of precancerous lesions.
    Frontiers of hormone research 01/2010; 38:70-6. · 1.24 Impact Factor
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    ABSTRACT: Chronic hepatitis B (HBV) and C (HCV) virus infections are the most important factors associated with hepatocellular carcinoma (HCC), but tumor prognosis remains poor due to the lack of diagnostic biomarkers. In order to identify novel diagnostic markers and therapeutic targets, the gene expression profile associated with viral and non-viral HCC was assessed in 9 tumor samples by oligo-microarrays. The differentially expressed genes were examined using a z-score and KEGG pathway for the search of ontological biological processes. We selected a non-redundant set of 15 genes with the lowest P value for clustering samples into three groups using the non-supervised algorithm k-means. Fisher's linear discriminant analysis was then applied in an exhaustive search of trios of genes that could be used to build classifiers for class distinction. Different transcriptional levels of genes were identified in HCC of different etiologies and from different HCC samples. When comparing HBV-HCC vs HCV-HCC, HBV-HCC/HCV-HCC vs non-viral (NV)-HCC, HBC-HCC vs NV-HCC, and HCV-HCC vs NV-HCC of the 58 non-redundant differentially expressed genes, only 6 genes (IKBKbeta, CREBBP, WNT10B, PRDX6, ITGAV, and IFNAR1) were found to be associated with hepatic carcinogenesis. By combining trios, classifiers could be generated, which correctly classified 100% of the samples. This expression profiling may provide a useful tool for research into the pathophysiology of HCC. A detailed understanding of how these distinct genes are involved in molecular pathways is of fundamental importance to the development of effective HCC chemoprevention and treatment.
    Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.] 11/2009; 42(12):119-1127. · 1.08 Impact Factor
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    ABSTRACT: To assess MHC I and II expressions in muscle fibres of juvenile dermatomyositis (JDM) and compare with the expression in polymyositis (PM), dermatomyositis (DM) and dystrophy. Forty-eight JDM patients and 17 controls (8 PM, 5 DM and 4 dystrophy) were studied. The mean age at disease onset was 7.1+/-3.0 years and the mean duration of weakness before biopsy was 9.4+/-12.9 months. Routinehistochemistry and immunohistochemistry (StreptABComplex/HRP) for MHC I and II (Dakopatts) were performed on serial frozen muscle sections in all patients. Mann-Whitney, Kruskal Wallis, chi-square and Fisher's exact statistical methods were used. MHC I expression was positive in 47 (97.9%) JDM cases. This expression was observed independent of time of disease, corticotherapy previous to muscle biopsy and to the grading of inflammation observed in clinical, laboratorial and histological parameters. The expression of MHC I was similar on JDM, PM and DM, and lower in dystrophy. On the other hand, MHC II expression was positive in just 28.2% of JDM cases and was correlated to histological features as inflammatory infiltrate, increased connective tissue and VAS for global degree of abnormality (p<0.05). MHC II expression was similar in DM/PM and lower in JDM and dystrophy, and it was based on the frequency of positive staining rather than to the degree of the MCH II expression. MHC I expression in muscle fibres is a premature and late marker of JDM patient independent to corticotherapy, and MHC II expression was lower in JDM than in PM and DM.
    Clinical and experimental rheumatology 01/2009; 27(3):519-26. · 2.66 Impact Factor
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    ABSTRACT: The mechanisms by which severe cholestatic hepatitis develops after liver transplantation are not fully understood. Reports on immunohistochemical distribution of hepatitis C virus (HCV) antigens are still scarce, but recently, HCV immunostaining was suggested for early diagnosis of cholestatic forms of recurrent hepatitis C in liver grafts. After purification, Rb246 pab anticore (aa1-68) yielded specific, granular cytoplasmic staining in hepatocytes. Signal amplification through the Envision-Alkaline Phosphatase System avoided endogenous biotin and peroxidase. Rb246 was applied to liver samples of explants of 12 transplant recipients, six with the most severe form of post-transplantation recurrence, severe cholestatic hepatitis (group 1) and six with mild recurrence (group 2). We also assessed immuno-reactivity at two time-points post-transplantation (median 4 and 22 months) in both groups. HCV-core Ag was semiquantified from 0 to 3+ in each time point. Serum HCV-RNA was also measured on the different time points by branched DNA. In the early post-transplant time point, one patient had a mild staining (1+), two patients had a moderate staining (2+) and the other three had no staining in group 1, compared with five patients with no staining (0) and one patient with mild staining (1+) in group 2. Late post-transplant liver samples were available in nine patients, and two out of four samples in group 1 showed a mild staining, compared with no staining patients in five patients in group 2. Strikingly, on the explant samples, HCV immunostaining was strongly positive in group 1, and mildly positive in group 2. Two out of five samples showed 3+ staining, and three samples showed 2+ staining in group 1; two out of five samples showed no staining, two samples showed 1+ staining and one sample showed 2+ staining in group 2. Serum HCV-RNA was significantly higher in group 1, on both time-points post-transplantation. HCV-core Ag was not directly associated with serum HCV-RNA on the different time points. These preliminary results suggest that strong HCV immunostaining in the explant is predictive of more severe disease recurrence.
    Liver international: official journal of the International Association for the Study of the Liver 05/2008; 28(6):807-13. · 3.87 Impact Factor
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    ABSTRACT: Hepatocyte proliferation and apoptosis (programmed cell death) occur during the liver parenchyma regeneration and the liver size modeling is mainly controlled by hepatocyte apoptosis. The purpose of the present study was to verify the influence of immunosuppressant drugs on these phenomena by utilizing tissue microarray techniques. Thirty-six weaning rats (age 21-23 days, weight 30-50 g) were divided into six groups: control, sham, hepatectomy, hepatectomy plus solumedrol, hepatectomy plus CsA, and hepatectomy plus Tac. The animals were killed one day after hepatectomy, and the remnant livers were weighed and harvested for tissue microarray sections. Liver cell proliferation was evaluated by staining for PCNA and apoptosis was detected by the TUNEL method. It was verified that CsA promoted a decrease in the liver weight, Tac and CsA decreased the proliferation index of hepatocytes, and glucocorticoid had no significant effects. The apoptosis index was not altered by hepatectomy or immunosuppressants. Our data indicate that, in the growing rat, CsA and Tac have negative effects on hepatocyte proliferation and have no effect on the hepatocyte apoptosis.
    Pediatric Transplantation 03/2008; 12(1):40-6. · 1.50 Impact Factor
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    ABSTRACT: A morphological evaluation of histopathological liver samples from 42 fulminant hepatic failure cases from the Amazon Basin was undertaken in order to differentiate yellow fever (YF) from Lábrea hepatitis (LH) and other entities. The pattern and distribution of liver cell death as well as ballooning degeneration and midzonal apoptotic bodies were the most distinctive features of YF, whereas morula cells were the major finding for LH. Nineteen well characterised cases were further submitted to immunohistochemical studies for expression of YF antigen, hepatitis B surface antigen (HBsAg) and delta virus antigen. In both diseases, but particularly in LH, portal vein branch phlebitis was evident and might have played a role in the pathogenesis of hepatic injury, leading to hepatic extinction and portal tract approximation. The regeneration pattern was remarkable: a high proliferative index was detected in YF, whereas in LH multinucleation and pseudoacinar transformation, associated with portal type I collagen deposition and portal elastic fibre proliferation, was seen. In conclusion, midzonal apoptosis, portal phlebitis and a high proliferative index in patients without evidence of previous liver injury was the dominant picture in YF. On the other hand, LH cases showed extensive, predominantly lytic hepatocytic necrosis, portal and hepatic vein phlebitis and morula cells in patients with a morphological background of chronic liver disease.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 09/2007; 101(8):831-9. · 1.82 Impact Factor
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    ABSTRACT: OBJECTIVES: The aim of this study was to evaluate the resolutivity of immunohistochemical (IHC) assays on neoplastic samples in a public health laboratory and to assess the influence of communication between the requiring institution and reference one on the quality of the IHC diagnosis. MATERIAL AND METHODS: One thousand oncological samples from eight public hospitals were submitted to IHC assay: 500 immediately before and 500 after an intervention demanding further information from the requiring pathologist. Antigen retrieval was performed in a pressure cooker and the detection system was LSAB plus System. The results were expressed as positive, negative or inconclusive. Information about paraffin blocks, fixatives, official requiring form, the attachment of original anatomopathological report, topography of the lesion, age and gender of the patients was collected. RESULTS AND CONCLUSION: From 989 samples, 5,719 slides were stained by IHC, leading to a resolutivity for 919/989 (92.9%). The number of antigen tested ranged from one to 22 – average of 5.8 for case. Panels with up to five antigens per case resolved 534 samples, whereas up to 10 markers were necessary to resolve 919 samples. Even nowadays, basic information, such as anatomopathological reports, age, gender, representative and technically superior paraffin block are not always available to the reference laboratory. The improvement of such communication is essential to rationalize the flux of immunohistochemical tests and to enhance the quality of diagnostic conclusions.
    Jornal Brasileiro de Patologia e Medicina Laboratorial 08/2007; 43(4):297-304.

Publication Stats

255 Citations
70.31 Total Impact Points

Institutions

  • 2013–2014
    • Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
      San Paulo, São Paulo, Brazil
  • 1989–2008
    • Instituto Adolfo Lutz
      • Pathology Division
      San Paulo, São Paulo, Brazil
  • 1991
    • University of São Paulo
      • Faculty of Medicine (FM)
      São Paulo, Estado de Sao Paulo, Brazil