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Govind Bhagat

Publications and source records attributed to Govind Bhagat.

34 records · Page 2Linked to original sources
PubMed2005

Congenital MLL-positive B-cell acute lymphoblastic leukemia (B-ALL) switched lineage at relapse to acute myelocytic leukemia (AML) with persistent t(4;11) and t(1;6) translocations and JH gene rearrangement.

Congenital acute leukemia is a rare form of childhood leukemia, in which lineage conversion at relapse is very rarely reported. Here we describe a case of congenital B-cell acute lymphoblastic leukemia (B-ALL) with t(4;11) and t(1;6) translocations, which at relapse underwent a switch to monocytic lineage with persistence of the original cytogenetic translocations and clonal rearrangement of the JH gene. Similar to the other described cases of congenital acute leukemia with lineage conversion, our case had a MLL gene rearrangement and followed an aggressive clinical course.

Burkitt Lymphoma↗
PubMed2005

Inflammatory bowel disease in patients with celiac disease.

BACKGROUND: Several case reports and series report an association between celiac disease and inflammatory bowel disease (IBD); however, there is no current data assessing this association. We therefore studied the occurrence of these conditions in a cohort of patients with celiac disease seen at a referral center. METHODS: A database of patients with celiac disease seen between 1981 and 2002 was analyzed. Only biopsy-proven adults were included. Patients who had endoscopic and pathologic evidence of IBD were identified, and their pathology was reviewed. Age- and sex-adjusted prevalence rate ratios were determined by comparing results with population-based prevalence data. RESULTS: Among 455 patients with celiac disease, IBD was identified in 10 (5 had ulcerative colitis and 5 had Crohn's disease). This represented an age- and sex-adjusted prevalence rate ratio for ulcerative colitis of 3.56 (95% confidence interval, 1.48-8.56) and for Crohn's disease of 8.49 (95% confidence interval, 3.53-20.42). CONCLUSION: Within our cohort of patients with celiac disease, IBD was significantly more common than in the general population.

Adult↗
PubMed2005

Characterizing CD43 expression in haematogones using multicolor flow cytometric analysis.

Haematogones are precursor B cells commonly detected in small numbers in the bone marrow. Morphologically, haematogones can mimic lymphoblasts and are best distinguished using multicolour flow cytometry with antibody combinations. Haematogones show characteristic and reproducible patterns of antigen expression representing the B-cell maturation sequence. CD43 expression, widely seen in haematopoietic elements, has not been well characterized in haematogones. We demonstrate that CD43 is consistently expressed in haematogones in a reproducible pattern similar to that of CD10 when combined with CD20. We propose that in combination with other markers, CD43 can be useful in the identification of haematogones.

Adolescent↗
PubMed2005

CD117 expression in diffuse large B-cell lymphomas: fact or fiction?

CD117 (KIT) is expressed in a variety of hematopoietic neoplasms but there are a paucity of data regarding its expression in diffuse large B-cell lymphomas (DLBCL). The purpose of the present paper was to describe the authors' experience of two CD117+ DLBCL (one of follicle center-cell origin and one nasal Epstein-Barr virus (EBV)- plasmablastic lymphoma associated with lytic bone lesions), as determined by tissue immunohistochemistry and flow cytometry. The CD117 expression in DLBCL was further evaluated using tissue microarrays and seven additional plasmablastic lymphomas, using two commercially available anti-CD117 antibodies (Ab-1, Oncogene and A4502, DakoCytomation). Membranous +/- cytoplasmic staining was seen with Ab-1 in 24/65 (37%) DLBCL, including 21/56 microarray DLBCL, two index cases, and 1/7 additional plasmablastic lymphomas, with persistent staining in 13% of microarray DLBCL despite preincubation with KIT peptide. However, A4502 had only membranous staining of the index cases and one additional EBV- plasmablastic lymphoma with medullary disease. The present study suggests that (i) CD117 expression can be detected sporadically in DLBCL of follicle center-cell origin and a subset of plasmablastic lymphomas; (ii) staining for CD117 might help in identifying EBV- plasmablastic lymphomas associated with bone marrow involvement; and (iii) CD117 antibodies should be carefully validated prior to use, because non-specific staining, as observed with Ab-1, could lead to false-positive results.

Bone Neoplasms↗
PubMed2005

Usefulness of CDX2 and TTF-1 in differentiating gastrointestinal from pulmonary carcinoids.

Carcinoids of different organs appear morphologically indistinguishable. We studied the usefulness of differential expression of CDX2 and thyroid transcription factor-1 (TTF-1) in 78 gastrointestinal and pulmonary carcinoids and their metastases (n = 10). CDX2 staining of gastric biopsy specimens with neuroendocrine hyperplasia (n = 11) and various gastritides (n = 10) was also performed. All ileal (6/6 [100%]), 6 (86%) of 7 appendiceal, 3 (75%) of 4 duodenal, 1 (50%) of 2 ampullary, 12 (33%) of 18 rectal, 6 (30%) of 20 pancreatic, and 1 (17%) of 6 gastric carcinoids expressed CDX2 with variable intensity; none of the pulmonary carcinoids stained. Of 15 pulmonary carcinoids, 8 (53%) stained with TTF-1, but none of the gastrointestinal carcinoids did. CDX2 and TTF-1 staining profiles of primary and metastatic carcinoids were similar. CDX2+ gastric endocrine cells had a distribution similar to that of gastrin and enterochromaffin cells but not enterochromaffin-like cells. Our results suggest that CDX2 and TTF-1 have high specificity for gastrointestinal and pulmonary carcinoids, respectively.

Adolescent↗
PubMed2004

Nomenclature of the finer branches of the biliary tree: canals, ductules, and ductular reactions in human livers.

The work of liver stem cell biologists, largely carried out in rodent models, has now started to manifest in human investigations and applications. We can now recognize complex regenerative processes in tissue specimens that had only been suspected for decades, but we also struggle to describe what we see in human tissues in a way that takes into account the findings from the animal investigations, using a language derived from species not, in fact, so much like our own. This international group of liver pathologists and hepatologists, most of whom are actively engaged in both clinical work and scientific research, seeks to arrive at a consensus on nomenclature for normal human livers and human reactive lesions that can facilitate more rapid advancement of our field.

Biliary Tract↗
PubMed2004

Coordinated induction by IL15 of a TCR-independent NKG2D signaling pathway converts CTL into lymphokine-activated killer cells in celiac disease.

A major function of NKG2D linking innate and adaptive immunity is to upregulate antigen-specific CTL-mediated cytotoxicity in tissues expressing stress-induced NKG2D ligands, such as MIC, by coactivating TCR signaling. Here, we show that, under conditions of dysregulated IL15 expression in vivo in patients with celiac disease and in vitro in healthy individuals, multiple steps of the NKG2D/DAP10 signaling pathway leading to ERK and JNK activation are coordinately primed to activate direct cytolytic function independent of TCR specificity in effector CD8 T cells. These findings may not only explain previous reports of transformation of CTL into NK-like "lymphokine-activated killers" (LAK cells) under high doses of IL2 (a substitute for IL15) but may also have significant implications for understanding and treating immunopathological diseases.

Adolescent↗
PubMed2004

Progenitor cell expansion: an important source of hepatocyte regeneration in chronic hepatitis.

BACKGROUND/AIMS: Progenitor cell activation with subsequent maturation to hepatocytes and cells of the biliary lineage has been demonstrated in a variety of chronic liver diseases but the kinetics and magnitude of the progenitor cell response has not been adequately studied in detail in chronic hepatitis. We undertook this study to evaluate factors responsible for the progenitor cell/ductular response and further dissect the role of disease grade and stage as determinants of hepatocellular differentiation of bipotential progenitor cells in chronic hepatitis. METHODS: Cytokeratin 7 (and 19) stained biopsies from patients with chronic hepatitis C (n = 47), hepatitis B (n = 20), and autoimmune hepatitis (n = 20) were studied. Ploidy analysis and proliferation indices were evaluated in a subset of cases. RESULTS: Ductular reactions were present in the majority of cases (97%), appeared early in disease, and correlated with disease activity, while progenitor cell derived hepatocyes appeared later in disease and their extent correlated with disease stage. Proliferation indices of all cell types correlated with disease activity. CONCLUSIONS: Progenitor cell derived hepatocytes accrue in chronic hepatitis, possibly related to native hepatocellular dysfunction. However, the fate of these hepatocytes is unclear.

Adolescent↗
PubMed2004

Mature B-cell acute lymphoblastic leukemia with t(9;11) translocation: a distinct subset of B-cell acute lymphoblastic leukemia.

Mature B-cell acute lymphoblastic leukemia (ALL) is typically associated with the FAB-L3 morphology and rearrangement of the MYC gene, features characteristic of the leukemic phase of Burkitt's lymphoma. However, the term 'mature' has also been used to describe other rare cases of B-ALL with light-chain surface immunoglobulin expression. In contrast, infantile B-cell ALL is generally characterized by rearrangement of the MLL gene, an immature pro-B-cell phenotype, and CD10 negativity. We describe two unusual cases of infantile B-ALL with non-L3 morphology, expressing a mature B-cell phenotype (lambda sIg+, CD19+, CD10-, TdT-, and CD34-), and showing MLL rearrangement without MYC rearrangement at presentation. Both infants relapsed after months of morphologic and genetic remission. At relapse, the t(9;11) translocation was detected in both cases by spectral karyotyping. After the initial relapse, both cases followed a rapid and aggressive course. Literature search identified few similar cases, all expressed lambda surface immunoglobulin and showed MLL rearrangement (majority with the t(9;11) translocation). These cases show that B-ALL with MLL rearrangement, especially the t(9;11) translocation, can express a 'mature' B-cell phenotype and may represent a distinct subset. Identification of additional cases will further clarify the significance of MLL rearrangements in mature B-ALL.

Antigens, CD↗
PubMed2004

EBV-associated, extranodal NK-cell lymphoma, nasal type of the breast, after heart transplantation.

Post-transplantation lymphoproliferative disorders (PTLDs) are predominantly Epstein-Barr virus (EBV)-associated B-cell lymphoproliferations. PTLDs of T-cell lineage are rare, mostly reported after renal transplantation and show less frequent association with EBV. NK-cell lymphomas after transplantation (NK-cell PTLDs) are very rare; only five cases are reported so far in the English literature, all developed after renal transplantation. We describe a case of EBV-associated, extranodal NK-cell lymphoma of nasal type, involving the breast in a cardiac allograft recipient 5 years after transplantation. The neoplastic cells are positive for CD2, cytoplasmic CD3, CD7, CD43, CD56, TIA-1 and p53; and negative for surface CD3 and CD57. Analysis of T-cell receptor beta and gamma genes fails to show clonal rearrangement. EBV studies show clonal episomal integration of EBV and latency II pattern (EBER-1+, LMP-1+, EBNA-1+, EBNA-2-). In conclusion, NK-cell PTLDs are rare complications that arise relatively late after solid organ transplantation, show strong association with EBV, and can follow an aggressive clinical course. To the best of our knowledge, we present the first reported case of NK-cell PTLD after cardiac transplantation and the unifying clinical and diagnostic features of NK-cell PTLDs occurring after solid organ transplantation.

Adult↗
PubMed2004

Hemophagocytic, non-secretory multiple myeloma.

A 70-year-old woman presented with pancytopenia associated with plasma cell infiltration of her bone marrow. The plasma cells were often multinucleated and demonstrated phagocytosis of erythroid and granulocytic cells. Atypical immunophenotypic features included the expression of CD117 and CD13 and the lack of expression of CD56. Although kappa chains were demonstrable in the cytoplasm, no paraprotein was found in the serum or urine. Osteolytic lesions were absent. The pancytopenia of this unusual patient with non-secretory, hemophagocytic myeloma has improved on dexamethasone monotherapy, although her hemophagocytosis persists.

Aged↗
PubMed2004

T-cell post-transplantation lymphoproliferative disorders after cardiac transplantation: a single institutional experience.

Post-transplantation lymphoproliferative disorders (PTLDs) are a well-recognized and potentially life-threatening complication of solid organ transplantation. While the vast majority of PTLDs are B-cell lymphoproliferations, T-cell PTLDs are rarely seen. Among 898 patients receiving cardiac transplants between 1990 and 2003, 34 patients (3.8%) developed PTLDs with two (0.2%) T-cell PTLDs, 31 (3.5%) B-cell PTLDs and one (0.1%) natural killer cell PTLD. An additional three cases of T-cell PTLD were identified among all cardiac transplant patients followed at our institution. These T-cell PTLDs comprised a heterogeneous group of Epstein-Barr virus negative lymphoproliferations that developed late after transplantation and followed an aggressive course.

Adult↗
PubMed2003

Promotion of tumorigenesis by heterozygous disruption of the beclin 1 autophagy gene.

Malignant cells often display defects in autophagy, an evolutionarily conserved pathway for degrading long-lived proteins and cytoplasmic organelles. However, as yet, there is no genetic evidence for a role of autophagy genes in tumor suppression. The beclin 1 autophagy gene is monoallelically deleted in 40-75% of cases of human sporadic breast, ovarian, and prostate cancer. Therefore, we used a targeted mutant mouse model to test the hypothesis that monoallelic deletion of beclin 1 promotes tumorigenesis. Here we show that heterozygous disruption of beclin 1 increases the frequency of spontaneous malignancies and accelerates the development of hepatitis B virus-induced premalignant lesions. Molecular analyses of tumors in beclin 1 heterozygous mice show that the remaining wild-type allele is neither mutated nor silenced. Furthermore, beclin 1 heterozygous disruption results in increased cellular proliferation and reduced autophagy in vivo. These findings demonstrate that beclin 1 is a haplo-insufficient tumor-suppressor gene and provide genetic evidence that autophagy is a novel mechanism of cell-growth control and tumor suppression. Thus, mutation of beclin 1 or other autophagy genes may contribute to the pathogenesis of human cancers.

Alleles↗
PubMed2003

Risk of malignancy in patients with celiac disease.

PURPOSE: Studies from Europe have demonstrated an increased risk of malignancy, especially non-Hodgkin's lymphoma, in patients with celiac disease. However, there are no data on the risk for similar patients in the United States. Our aim was to estimate the risk of malignancy in a cohort of patients with celiac disease compared with the general U.S. population and to determine if a gluten-free diet is protective. METHODS: Patients with celiac disease seen between July 1981 and January 2000 at a referral center were included. Standardized morbidity ratios (SMRs) (ratio of observed to expected) and corresponding 95% confidence intervals (CI) were calculated, using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. RESULTS: Forty-three (11%) of 381 celiac disease patients had a diagnosis of cancer; 9 were after the diagnosis of celiac disease, 7 were simultaneous (during same month or admission), and 27 were before the diagnosis. The standardized morbidity ratio for all cancers combined was 1.5 (95% CI: 0.3 to 7.5), with significantly increased values for small bowel cancer (SMR = 34; 95% CI: 24 to 42), esophageal cancer (SMR = 12; 95% CI: 6.5 to 21), non-Hodgkin's lymphoma (SMR = 9.1; 95% CI: 4.7 to 13), and melanoma (SMR = 5.0; 95% CI: 2.1 to 12). Following the diagnosis of celiac disease, patients were at increased risk of non-Hodgkin's lymphoma only (SMR = 6.2; 95% CI: 2.9 to 14), despite adherence to a gluten-free diet. The non-Hodgkin's lymphoma included both T-cell and B-cell types and occurred in both gastrointestinal (n = 5) and extraintestinal sites (n = 4). CONCLUSION: In this cohort of patients with celiac disease, we observed increased risks of small intestinal adenocarcinoma, esophageal cancer, melanoma, and non-Hodgkin's lymphoma. The risk of non-Hodgkin's lymphoma persisted despite a gluten-free diet.

Adult↗
PubMed2003

Mitochondrial DNA dysfunction in oncocytic hepatocytes.

Hepatic oncocytes with abundant granular, eosinophilic cytoplasm due to mitochondrial hyperplasia are seen in various chronic liver diseases, particularly chronic hepatitis and cirrhosis. Increased mitochondria in oncocytes are thought to be a compensatory mechanism for deficiencies in the hepatocellular respiratory chain, although the pathogenesis of these deficiencies has been uncertain. We selected seven cases of cirrhosis (six with oncocytes, one without) for the following analysis: histoenzymatic and immunohistochemical staining of several mitochondrial DNA (mtDNA)- and nuclear DNA (nDNA)-encoded respiratory chain enzymes; immunostaining using antibodies against double-strand-DNA (anti-DNA) and against Ki-67 (a cell proliferation marker); and Southern blot analysis for mtDNA and nDNA. Eighty percent of oncocytes showed histoenzymatic and immunohistochemical deficiencies of cytochrome c oxidase and the mtDNA-encoded subunit I of complex IV, with preserved expression of nDNA-encoded succinate dehydrogenase and the iron-sulfur subunit of complex III (FeS). Cytoplasmic (but not nuclear) anti-DNA staining was partially or completely absent in approximately 50% of oncocytes. Three cases with oncocytes studied by Southern blot showed mtDNA reductions of 66%, 71%, and 85%. In conclusion, hepatic oncocytes demonstrate significant deficiencies of mtDNA and mtDNA-encoded respiratory chain enzymes. We propose that mtDNA depletion plays an important role in hepatocellular oncocytic transformation.

Adult↗