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Biomedical subjects

Arundhati Rao

Publications and source records attributed to Arundhati Rao.

7 recordsLinked to original sources

Retinitis pigmentosa and hypogammaglobulinemia.

This report describes a family demonstrating an unusual association of retinitis pigmentosa and hypogammaglobulinemia. The proband in this family suffered from another rare illness, ie, Sertoli cell only syndrome. The incidence of retinitis pigmentosa is 1 in 5,000 and that of common variable immunodeficiency state is 1 in 100,000, making a chance association of these illnesses very unlikely.

Adult↗

Characterization of a recurrent germ line mutation of the E-cadherin gene: implications for genetic testing and clinical management.

PURPOSE: To identify germ line CDH1 mutations in hereditary diffuse gastric cancer (HDGC) families and develop guidelines for management of at risk individuals. EXPERIMENTAL DESIGN: We ascertained 31 HDGC previously unreported families, including 10 isolated early-onset diffuse gastric cancer (DGC) cases. Screening for CDH1 germ line mutations was done by denaturing high-performance liquid chromatography and automated DNA sequencing. RESULTS: We identified eight inactivating and one missense CDH1 germ line mutation. The missense mutation conferred in vitro loss of protein function. Two families had the previously described 1003C>T nonsense mutation. Haplotype analysis revealed this to be a recurrent and not a founder mutation. Thirty-six percent (5 of 14) of the families with a documented DGC diagnosed before the age of 50 and other cases of gastric cancer carried CDH1 germ line mutations. Two of 10 isolated cases of DGC in individuals ages <35 years harbored CDH1 germ line mutations. One mutation positive family was ascertained through a family history of lobular breast cancer (LBC) and another through an individual with both DGC and LBC. Occult DGC was identified in five of six prophylactic gastrectomies done on asymptomatic, endoscopically negative 1003C>T mutation carriers. CONCLUSIONS: In addition to families with a strong history of early-onset DGC, CDH1 mutation screening should be offered to isolated cases of DGC in individuals ages <35 years and for families with multiple cases of LBC, with any history of DGC or unspecified GI malignancies. Prophylactic gastrectomy is potentially a lifesaving procedure and clinical breast screening is recommended for asymptomatic mutation carriers.

Adult↗

Role of calcitonin gene-related peptide in hypertension-induced renal damage.

Calcitonin gene-related peptide, a potent vasodilator neuropeptide, is localized in perivascular sensory nerves. We have reported that alpha-calcitonin gene-related peptide knockout mice have elevated baseline blood pressure and enhanced hypertension-induced renal damage compared with wild-type controls. Thus, the aim of this study was to determine the mechanism and functional significance of this increased hypertension-induced renal damage. We previously demonstrated by telemetric recording that the deoxycorticosterone-salt protocol produces a 35% increase in mean arterial pressure in both alpha-calcitonin gene-related peptide knockout and wild-type mice. Both strains of mice were studied at 0, 14, and 21 days after deoxycorticosterone-salt hypertension. Renal sections from hypertensive wild-type mice showed no pathological changes at any time point studied. However, on days 14 and 21, hypertensive knockout mice displayed progressive increases in glomerular proliferation, crescent formation, and tubular protein casts, as well as the inflammatory markers intercellular adhesion molecule-1, vascular adhesion molecule-1, and monocyte chemoattractant protein-1. There was a significant increase in 24-hour urinary isoprostane, a marker of oxidative stress-induced lipid peroxidation, levels at days 14 and 21 in the hypertensive knockout compared with hypertensive wild-type mice. Urinary microalbumin was significantly higher (2-fold) at day 21 and creatinine clearance was significantly decreased 4-fold in the hypertensive knockout compared with hypertensive wild-type mice. Therefore, in the absence of alpha-calcitonin gene-related peptide, deoxycorticosterone-salt hypertension induces enhanced oxidative stress, inflammation, and renal histopathologic damage, resulting in reduced renal function. Thus, sensory nerves, via alpha-calcitonin gene-related peptide, appear to be renoprotective against hypertension-induced damage.

Albuminuria↗

Calcitonin gene-related peptide protects against hypertension-induced heart and kidney damage.

Calcitonin gene-related peptide is a potent vasodilator neuropeptide that is localized in perivascular sensory nerves. To determine whether alpha-calcitonin gene-related peptide possesses protective activity against hypertension-induced end organ damage, hypertension was induced in alpha-calcitonin gene-related/calcitonin peptide knockout and wild-type mice by uninephrectomy, deoxycorticosteroid administration, and 0.9% saline drinking water. These mice were instrumented previously for long-term telemetric blood pressure recording. Control groups were sham-operated and given tap water. Mean arterial pressures were determined, and 3 weeks after initiation of each protocol, tissues were taken for histopathologic studies. The deoxycorticosteroid-salt protocol produced a significant 35% mean arterial pressure increase in both mouse strains. No pathological changes were observed in sections of aortas and femoral arteries from any of the groups studied. Likewise, heart and kidney sections from the hypertensive wild-type mice showed no pathological changes compared with their normotensive counterparts. In contrast, marked vasculitis was seen in the heart sections from the deoxycorticosteroid-salt-treated alpha-calcitonin gene-related peptide knockout mice with thickening and inflammation of the vessel walls. In addition, myocarditis and focal epicarditis with areas of myocardial necrosis were present. Kidneys of these mice exhibited prominent glomerular changes including congestion of the capillary loops, focal mesangial and crescent proliferation, and focal histocytic infiltration. Urinary microalbumin was significantly higher in the hypertensive alpha-calcitonin gene-related peptide knockout compared with hypertensive wild-type mice. These data suggest that deletion of the alpha-calcitonin gene-related peptide gene makes the heart and kidneys more vulnerable to hypertension-induced end organ damage.

Albuminuria↗

Erythema marginatum and hereditary angioedema.

OBJECTIVE: To search for anaphylatoxin activity in plasma during episodes of erythema marginatum, and to evaluate the histology of erythema marginatum by electron microscopy and immunohistologic techniques. METHODS: Plasma samples were studied for C5a activity by granulocyte aggregation, and C3 conversion by immunoelectrophoresis. A skin biopsy of erythema marginatum was done, and the tissue stained with a rabbit antibody to bradykinin. RESULTS: No plasma anaphylatoxin was found. Dense deposits of bradykinin were discovered in stromal tissue and lining endothelial cells. CONCLUSIONS: Bradykinin may be important in the causality of the erythema marginatum associated with hereditary angioedema.

Adult↗

Expression of vascular endothelial growth factor and HER2/neu in stage II colon cancer and correlation with survival.

Monoclonal antibody-directed therapy has been used as an effective treatment for some cancers that overexpress HER2/neu and vascular endothelial growth factor (VEGF). Overexpression of the HER2/neu oncogene and VEGF has been reported to occur in adenocarcinomas of the colon. Assessing whether HER2/neu and VEGF overexpression could serve as prognostic indicators for stage II colon cancer may provide insight into optimal treatment following surgery. Demographic and tumor characteristics from 109 patients diagnosed with stage II colon cancer between 1991 and 1996 were assessed for HER2/neu and VEGF expression using immunohistochemical staining techniques. Of the 109 cases, 107 (98%) were histologically classified as adenocarcinomas, 105 (96%) were grades 2/3, and 105 (96%) were stage T3. Only 12 cases (11%) exhibited HER2/neu overexpression and 72 cases (66%) exhibited VEGF expression. There was no significant difference in overall survival or in time to recurrence between the groups with and without HER2/neu overexpression. There was a trend toward decreased overall survival with VEGF expression (P = 0.07), but no difference in time to recurrence (P = 0.63). There were 18 patients who received adjuvant chemotherapy, but removal of these patients from the analysis did not change the results. There was no association between HER2/neu and VEGF expression and patient demographics or tumor characteristics, with the exception of VEGF expression and mucinous histology (P < 0.01). Our results do not support an association between HER2/neu or VEGF expression and overall survival or time to recurrence in stage II colon cancer. With further investigation, a significant correlation may be found between VEGF expression and prognosis, and thus direct therapy with a monoclonal antibody.

Adenocarcinoma↗