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Sunil Singhal

Publications and source records attributed to Sunil Singhal.

17 recordsLinked to original sources
PubMed2006

Gene induction during differentiation of human pulmonary type II cells in vitro.

Mature alveolar type II cells that produce pulmonary surfactant are essential for adaptation to extrauterine life. We profiled gene expression in human fetal lung epithelial cells cultured in serum-free medium containing dexamethasone and cyclic AMP, a treatment that induces differentiation of type II cells. Microarray analysis identified 388 genes that were induced > 1.5-fold by 72 h of hormone treatment. Induced genes represented all categories of molecular function and subcellular location, with increased frequency in the categories of ionic channel, cell adhesion, surface film, lysosome, extracellular matrix, and basement membrane. In time-course experiments, self-organizing map analysis identified a cluster of 17 genes that were slowly but highly induced (5- to approximately 190-fold) and represented four functional categories: surfactant-related (SFTPC, SFTPA, PGC, SFTPB, LAMP3, LPL), regulatory (WIF2, IGF2, IL1RL1, NR4A2, HIF3A), metabolic (MAOA, ADH1B, SEPP1), and transport (SCNN1A, CLDN18, AQP4). Induction of both mRNA and protein for these genes, which included nine newly identified regulated genes, was confirmed, and cellular localization was determined in both fetal and postnatal tissue. Induction of lysosomal-associated membrane protein 3 required both hormones, and expression was localized to limiting membranes of lamellar bodies. Hormone-induced differentiation of human type II cells is associated with genome-wide increased expression of genes with diverse functions.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2006

Benign pneumatosis intestinalis in the setting of celiac disease.

Pneumatosis intestinalis is an uncommon finding that may indicate the presence of several alarming pathological conditions, including bowel ischemia, that require urgent surgical intervention. We report the case of a 51-year-old man with celiac disease who underwent resection of a large duodenal adenocarcinoma. Although he initially recovered rapidly from his procedure, he subsequently developed abdominal distention and leukocytosis. Abdominal imaging revealed extensive small bowel pneumatosis and pneumoperitoneum. Emergent surgical exploration revealed only bowel wall air cysts and dilated bowel but failed to demonstrate any intra-abdominal pathology. The patient recovered uneventfully and was discharged without any further complications or recurrence of symptoms. We review the current literature on the rare finding of pneumatosis intestinalis in the setting of celiac disease. In all reported cases, even when pneumatosis is accompanied by pneumoperitoneum, these alarming findings have proved to be of "benign" origin, that is with no evidence of bowel ischemia, perforation, or peritonitis. The available evidence suggests that pneumatosis in the setting of celiac disease may reflect the dissection of intraluminal gas into the inflamed bowel wall without accompanying intra-abdominal pathology. We conclude that pneumatosis intestinalis, even with accompanying pneumoperitoneum, does not uniformly mandate surgical exploration in patients with celiac disease.

Adenocarcinoma↗
PubMed2005

Prognostic implications of cell cycle, apoptosis, and angiogenesis biomarkers in non-small cell lung cancer: a review.

Lung cancer is the leading cause of cancer death in the U.S. with survival restricted to a subset of those patients able to undergo surgical resection. However, even with surgery, recurrence rates range from 30% to 60%, depending on the pathologic stage. With the advent of partially effective, but potentially toxic adjuvant chemotherapy, it has become increasingly important to discover biomarkers that will identify those patients who have the highest likelihood of recurrence and who thus might benefit most from adjuvant chemotherapy. Hundreds of papers have appeared over the past several decades proposing a variety of molecular markers or proteins that may have prognostic significance in non-small cell lung cancer. This review analyzes the largest and most rigorous of these studies with the aim of compiling the most important prognostic markers in early stage non-small cell lung cancer. In this review, we focused on biomarkers primarily involved in one of three major pathways: cell cycle regulation, apoptosis, and angiogenesis. Although no single marker has yet been shown to be perfect in predicting patient outcome, a profile based on the best of these markers may prove useful in directing patient therapy. The markers with the strongest evidence as independent predictors of patient outcome include cyclin E, cyclin B1, p21, p27, p16, survivin, collagen XVIII, and vascular endothelial cell growth factor.

Apoptosis↗
PubMed2005

Gene expression signature predicts lymphatic metastasis in squamous cell carcinoma of the oral cavity.

Metastasis via the lymphatics is a major risk factor in squamous cell carcinoma of the oral cavity (OSCC). We sought to determine whether the presence of metastasis in the regional lymph node could be predicted by a gene expression signature of the primary tumor. A total of 18 OSCCs were characterized for gene expression by hybridizing RNA to Affymetrix U133A gene chips. Genes with differential expression were identified using a permutation technique and verified by quantitative RT-PCR and immunohistochemistry. A predictive rule was built using a support vector machine, and the accuracy of the rule was evaluated using crossvalidation on the original data set and prediction of an independent set of four patients. Metastatic primary tumors could be differentiated from nonmetastatic primary tumors by a signature gene set of 116 genes. This signature gene set correctly predicted the four independent patients as well as associating five lymph node metastases from the original patient set with the metastatic primary tumor group. We concluded that lymph node metastasis could be predicted by gene expression profiles of primary oral cavity squamous cell carcinomas. The presence of a gene expression signature for lymph node metastasis indicates that clinical testing to assess risk for lymph node metastasis should be possible.

Adult↗
PubMed2004

Evolving options in the management of esophageal perforation.

Esophageal perforation remains a devastating event that is difficult to diagnose and manage. The majority of injuries are iatrogenic and the increasing use of endoscopic procedures can be expected to lead to an even higher incidence of esophageal perforation in coming years. Accurate diagnosis and effective treatment depend on early recognition of clinical features and accurate interpretation of diagnostic imaging. Outcome is determined by the cause and location of the injury, the presence of concomitant esophageal disease, and the interval between perforation and initiation of therapy. The overall mortality associated with esophageal perforation can approach 20%, and delay in treatment of more than 24 hours after perforation can result in a doubling of mortality. Surgical primary repair, with or without reinforcement, is the most successful treatment option in the management of esophageal perforation and reduces mortality by 50% to 70% compared with other interventional therapies.

Esophageal Perforation↗
PubMed2004

Immuno-gene therapy with interferon-beta before surgical debulking delays recurrence and improves survival in a murine model of malignant mesothelioma.

OBJECTIVES: Immuno-gene therapy of mesothelioma with an adenovirus encoding interferon-beta mediated strong antitumor responses in murine models with low but not high tumor burden. Our goals were to determine the mechanisms responsible for this loss of efficacy and to test the hypothesis that the combination of preoperative adenovirus encoding interferon-beta and surgical resection would be effective in treating bulky tumors. METHODS: Flank tumors of a mouse mesothelioma cell line were treated with adenovirus encoding interferon-beta or adenoviral vector encoding the bacterial protein beta-galactosidase. Cytotoxic T lymphocytes and tumor infiltration by T lymphocytes were measured. Tumors were surgically excised 72 hours later and tumor cells were injected in the contralateral flank to create a model of a metastatic focus. Tumor-free survival and distant metastatic disease were assessed. RESULTS: Immuno-gene therapy effectively treated small tumors (<200 mm(3)) but did not reduce the size of large (>800 mm(3)) flank tumors. Although treatment with adenovirus encoding interferon-beta resulted in the generation of tumor-neutralizing splenocytes in large tumors, the number of T cells visualized within the tumors was minimal. Tumors treated with adenovirus encoding interferon-beta (versus adenoviral vector encoding the bacterial protein beta-galactosidase or phosphate-buffered saline solution) prior to debulking increased long-term tumor-free survival and resulted in two- to sixfold smaller foci of implanted tumor cells at 2 weeks postoperatively. CONCLUSIONS: The use of adenovirus encoding interferon-beta or surgical debulking alone is ineffective in treating large tumors, but combining preoperative adenovirus encoding interferon-beta and surgical debulking significantly reduces tumor recurrence and improves long-term tumor-free survival. We postulate that adenovirus encoding interferon-beta amplifies the cytotoxic T-lymphocyte antitumor response, allowing elimination of residual tumor cells.

Adenoviridae↗
PubMed2003

Gene expression profiling of malignant mesothelioma.

PURPOSE: Malignant mesothelioma is a uniformly fatal cancer of the pleural and peritoneal spaces. Several challenging clinical problems include poor understanding of the pathophysiology, inaccurate diagnosis from tissue samples, and unsuccessful treatment strategies. The purpose of this study was to use microarray analysis to identify specific gene expression changes in mesothelioma compared with normal mesothelium. EXPERIMENTAL DESIGN: We performed gene expression analysis on mesothelioma tissue specimens from 16 patients and compared these to 4 control pleural tissue samples using cDNA microarray filters with 4132 clones. Multiple normalization and analysis approaches were used. Quantitative reverse transcription-PCR and immunohistochemistry were used to validate results. RESULTS: Genes (166) were significantly up-regulated, and 26 were down-regulated. Validation of 18 genes using real-time PCR confirmed array predictions in every case. Analysis revealed activation of several key pathways including genes involved in glucose metabolism, mRNA translation, and cytoskeletal remodeling. Expression profiling identified processes likely responsible for 18-fluoro-2-deoxy-glucose uptake and tumor localization by positron emission tomography, and a role for hypoxia-inducible factor-1 was suggested. Potentially important up-regulated genes included gp96, lung resistance-related protein, galectin-3 binding protein, the M(r) 67,000 laminin receptor (on tumor vessels), and voltage-dependent anion channels. Prospective testing using reverse transcription-PCR confirmed up-regulation of these novel markers. CONCLUSIONS: Expression profiling revealed marked up-regulation of energy, protein translation, and cytoskeletal remodeling pathways in mesothelioma. Additional genes that could be important in our understanding of the pathogenesis of mesothelioma, aiding in diagnosis, or improving targets for therapy were also identified.

Aged↗
PubMed2003

Bronchial sleeve resection for posttransplant stricture.

Nonanastomotic bronchial stenosis is a rare complication of lung transplantation. We report a case of a bilateral lung transplant recipient who experienced recalcitrant stenosis of the bronchus intermedius. All attempts at conservative management failed, and the stricture was successfully treated by a parenchymal-sparing segmental sleeve resection. Although rare, this is an important technique in the management of this difficult problem.

Bronchi↗
PubMed2003

Comparison of stages I-II thymoma treated by complete resection with or without adjuvant radiation.

BACKGROUND: Adjuvant radiation after resection of Masaoka stage II thymoma is widely advocated, but the evidence supporting it is controversial. Studies addressing this issue generally report few patients and lump all patients beyond stage I together in the analysis. METHODS: We retrospectively compared outcomes of stage I and II thymomas treated by resection alone with thymomas treated by resection plus radiation. Histology was re-reviewed to confirm pathologic staging and resection margin status. RESULTS: Between February 1992 and 2002, we performed 167 resections for thymoma. Of these, 70 patients were believed to have tumors in stage IIb or less intraoperatively, and all of these patients underwent complete resection. We reviewed the histopathology of 62 of 70 patients. Thirty thymomas demonstrated less than complete transcapsular microscopic invasion (stage I) and 40 thymomas demonstrated microscopic transcapsular invasion or macroscopic invasion into surrounding fatty tissue (stage II). Forty-seven patients underwent surgery without postoperative mediastinal radiotherapy. Dosages in the 23 radiated patients (3 stage I and 20 stage II) consisted of 45 to 55 Gy. Median follow-up was 70.3 months. Stage II patients who were radiated (n = 20) and those who were not radiated (n = 20) consisted of identical proportions in stages IIa and IIb. Two patients recurred (1 unradiated stage I patient and 1 radiated stage IIb patient). Overall 5-year survival rate was 91%. All who died were free of recurrence at time of death. Log-rank test showed no difference in Kaplan Meier survival curves (p = 0.32) between the radiated and unradiated groups. CONCLUSIONS: These data support the contention that margin-negative surgical resection alone is sufficient treatment for both stages I and II thymoma.

Adult↗
PubMed2003

Suramin inhibits the growth of malignant mesothelioma in vitro, and in vivo, in murine flank and intraperitoneal models.

Surgical debulking of malignant mesothelioma (MM) ultimately fails due to local recurrence. Suramin, an inhibitor of extracellular growth factors (ECGFs), has demonstrated efficacy in the treatment of malignant mesothelioma in a small case series. Our goal was to study survival benefits and disease progression in several MM animal models treated with suramin as a potential agent for adjuvant therapy. In vitro growth of human (REN, I-45), rat (II-45) and murine (AB12) mesothelioma cell lines were measured with or without suramin exposure. Human and murine MM tumors were implanted subcutaneously into murine flanks or injected intraperitoneally (i.p.) into murine abdominal cavities. Dose and treatment schedules were optimized to reduce the rate of tumor progression and to improve survival curves. Suramin inhibited the in vitro growth of all cell lines, reaching statistical significance (P<0.01) three doubling cycles after suramin administration, with a maximum inhibition of 10-25% of control growth. A significant time- and dose-dependent effect was observed. In vivo, suramin inhibited the growth of MM in the xenogeneic model (55% of control growth, P<0.01), and in the syngeneic model at both the low and high loading doses (46 and 36% of control growth, respectively, P<0.01). Suramin treatment inhibited in vivo growth in the REN intraperitoneal model shown grossly by necropsy of same day deaths comparing treatment and control animals. Tumor inhibition with the higher dose was also reflected by the lower mean tumor burden scores (control: 4.0 and high dose: 3.4). Suramin inhibits the growth of human, murine, and rat MM in vitro, in a time- and dose-dependent manner. Suramin also inhibits the growth of human MM flank and intraperitoneal xenografts in vivo in an immunodeficient host, as well as the growth of syngeneic murine flank tumors in an immunocompetent host. These studies demonstrate that suramin may have the potential to provide effective therapy for MM, and that further studies are necessary to elucidate the survival advantage of suramin mediated MM growth inhibition.

Animals↗
PubMed2003

Giant bullous lung disease: evaluation, selection, techniques, and outcomes.

Patient selection remains one of the most important aspects of successful surgery for bullous disease. Operation is indicated for patients who have incapacitating dyspnea with large bullae that fill more than 30% of the hemithorax and result in the compression of healthy adjacent lung tissue. Operation is also indicated for patients who have complications related to bullous disease such as infection or pneumothorax. Patients who have bullous disease in the presence of diffuse lung disease (emphysematous or nonemphysematous) should be evaluated on an individual basis and surgery should be performed on patients in whom even a small increase in pulmonary function might be of major benefit. Smoking cessation and outpatient pulmonary rehabilitation are required of all patients preoperatively. Patients should undergo PFTs including lung volumes by whole body plethysmography, spirometry, diffusion capacity, and arterial blood gas. CT remains the most important preoperative evaluation because it is useful assessing the extent of bullous disease and the quality of the surrounding lung tissue. The authors favor a minimally invasive technique through VATS whenever possible because it might allow for a quicker recovery and might be associated with less pain than is seen following thoracotomy. Modified Monaldi-type drainage procedures are also effective, especially in high-risk patients who cannot tolerate excisional procedures. Special care must be taken to avoid sacrifice of any potentially functional lung tissue. Lobectomies should be avoided whenever possible. The best results are seen in limited resections of large bullae that spare all surrounding functional pulmonary parenchyma. Postoperative complications are minimized through aggressive tracheobronchial toilet and vigorous chest physiotherapy. Adequate pain control in maintained throughout the postoperative period, initially by way of epidural infusion of morphine or fentanyl and later through oral opioids. Early ambulation and pulmonary rehabilitation also help minimize complications.

Drainage↗
PubMed2003

Gene expression profiling of the early pulmonary response to hyperoxia in mice.

To identify molecular events occurring during the early response to hyperoxia, we measured changes over time in total lung gene expression in C57BL/6 mice during prolonged exposure to > 95% O2. Specifically, differential gene expression of > 8,734 sequence-verified murine complementary DNAs was analyzed after 0, 8, 24, and 48 h of O2 exposure, with additional genes of interest analyzed at 24 h. Of the 385 genes differentially expressed, hyperoxia increased expression of 175 genes (2.0%) and decreased expression of 210 genes (2.3%). The majority of "classic" antioxidant enzymes, including catalase, MnSOD, and Cu-Zn SOD, showed no change in expression during hyperoxia, with a number of other antioxidant enzymes, including glutathione peroxidase, glutathione-S-Transferase (GST) Pi1, GST mu2, and heme oxygenase-1 showing relatively moderate increases. The exception was the heavy metal-binding protein metallothionein, which increased expression over 7-fold after 48 h of O2. We found no change in the expression of a number of known proinflammatory genes after 24 or 48 h of hyperoxia. A large increase in p21 expression was demonstrated, suggesting overall inhibition of cell cycle progression. Increases of the antiapoptotic gene Bcl-XL were counterbalanced by similar increases of the proapoptotic gene BAX. New findings included significant increases in expression of cysteine-rich protein 61(cyr61) at 48 h, suggesting a potential role for this factor in angiogenesis or remodeling of the extra cellular matrix during recovery from hyperoxia. In addition, downregulation of thrombomodulin expression occurred by 24 h and was further decreased at 48 h. Given the importance of thrombomodulin/thrombin interaction in regulating protein C activity, decreases in thrombomodulin may contribute to activation of the coagulation and inflammatory cascades and development of lung injury with hyperoxia.

Animals↗
PubMed2002

Malignant mesothelioma: options for management.

In the past, there has been a tendency to think of diffuse malignant pleural mesothelioma as one disease in therapeutic terms, regardless of histological type and tumor stage. This does not happen with other tumors, yet it is equally illogical and inappropriate in mesothelioma. As with other tumors, early diagnosis-while the disease is still in stage I, or even at an in situ stage-must be the goal so that therapy can be maximized, particularly if immunotherapy or gene therapy is to be used. Patients with pure epithelial mesothelioma have a better prognosis and respond better to trimodality therapy. Stage I patients who meet fitness criteria should be offered the option of radical surgery in combination with chemotherapy and radiotherapy. Further research is required to determine the optimum neoadjuvant and adjuvant modalities, particularly the timing of individual drugs, use of hyperthermia, and route of administration. The place of immunotherapy and gene therapy as adjunctive treatments also remains to be defined. For example, it may be possible to reduce tumor bulk and perhaps downstage the disease with immunotherapy before radical surgery, if treatment is started early enough. Gene therapy may have a role either preoperatively or in destroying the microscopic disease that remains after radical surgery. These and other combinations of treatment need to be tested in well-designed clinical trials, probably on a multicenter basis (to enroll a sufficient number of patients). Finding the means to improve treatment for sarcomatous and mixed histology mesothelioma remains a challenge. At present, radical surgery does not seem worthwhile for these patients when combined with currently employed chemotherapy and radiotherapy; however, chemotherapy combinations used for treating other sarcomas need to be evaluated as adjunctive therapy before radical surgery is abandoned altogether as a mode of treatment. A collaborative approach involving thoracic surgeons, basic scientists and oncologists, and physicians with experience in treating mesothelioma is essential. Despite its increasing frequency, mesothelioma is still a relatively rare tumor, so treatment should be concentrated in relatively few supraregional centers to maximize expertise and allow innovative treatment combinations to be implemented with the greatest chance of success. Evaluation of new therapeutic approaches will be achieved more rapidly if these supraregional centers collaborate in multicenter trials. The nihilistic approach of simply waiting until the mesothelioma epidemic eventually begins to decline spontaneously in 20 or 30 years is untenable in view of the hundreds of thousands of deaths that will result if no effective treatment is found.

Humans↗
PubMedDate not supplied

Alterations in cell cycle genes in early stage lung adenocarcinoma identified by expression profiling.

In normal lung epithelial cells, cellular division is an ordered, tightly regulated process involving multiple checkpoints that assess extracellular growth signals, cell size, and DNA integrity. In contrast, neoplastic lung cells develop the ability to bypass several of these checkpoints, particularly at the G1/S and G2/M boundaries. We used genomic profiling to compare gene expression levels in early stage lung adenocarcinomas and non-neoplastic pulmonary tissue in order to comprehensively identify alterations in the process of cell cycling. RNA extracted from node negative, poorly differentiated lung adenocarcinomas (15 patients) and non-neoplastic pulmonary tissue (5 patients) was hybridized to oligonu-cleotide microarray filters containing 44,363 genes. Ontological classification was used to extract genes involved with cell cycle progression. Further analysis discovered a subset of differentially expressed genes for further study. Of the 624 cell cycle genes on the microarray filters, 40 genes were predicted to be differentially expressed in lung adeno-carcinomas. Alterations in several genes (i.e., cyclin B1, cyclin D1, p21, MDM2) are consistent with published data in the literature. We also identified 19 novel genes that have neither been described in non-small cell lung cancer (i.e., cdc2, cullin 4A, ZAC, p57, DP-1, GADD45, PISSLRE, cdc20) nor in any other tumors (i.e., cyclin F, cullin 5, p34). These results identified several potential cell cycle genes altered in lung cancer.

Adenocarcinoma↗
PubMedDate not supplied

Microarray data simulator for improved selection of differentially expressed genes.

The development of microarray technology has allowed researchers to measure expression levels of thousands of genes simultaneously. Analysis of these data requires the best normalization and statistical approaches to account for the biological and technical variability inherent in the technique. To approach this problem we have developed a publicly available simulator of microarray hybridization experiments that can be used to help assess the accuracy of bioinformatic tools in discovering significant genes. After analyzing microarray hybridization experiments from over 50 samples, an estimate of various degrees of technical and biological variability was obtained. This information was used to develop a simulator of microarray hybridization data which modeled "normal tissue samples" and "diseased tissue samples" with known, defined, changes in gene expression (a "gold standard"). The data derived from the simulator were then used to evaluate the true positive and false negative rates of several normalization procedures and gene selection techniques. We found that the type of normalization approach used was an important aspect of data analysis. Global normalization was the least accurate approach. Evaluation of gene selection techniques showed that "Significance analysis of microarrays" (SAM) and "Patterns of Gene Expression" (PaGE) were more accurate than simple t-test analysis. We provide access to the microarray hybridization simulator as a public resource for biologists to further test new emerging genomic bioinfomatic tools.

Computer Simulation↗
PubMedDate not supplied

Differentially expressed apoptotic genes in early stage lung adenocarcinoma predicted by expression profiling.

OBJECTIVE: In undiseased lung epithelial cells, apoptosis is an evolutionarily conserved and genetically regulated form of cell suicide which plays an important role in development and in the maintenance of tissue homeostasis. Neoplastic lung cells develop the ability to deregulate growth by alterations in these genes which control apoptosis. Genomic profiling was used to compare gene expression levels in early stage lung adenocarcinomas and nonneoplastic pulmonary tissue in order to comprehensively identify alterations in the process of apoptosis. METHODS: RNA extracted from node negative, poorly differentiated lung adenocarcinomas (15 patients) and nonneoplastic pulmonary tissue (5 patients) was hybridized to oligonucleotide microarray filters containing 44,363 genes. Ontological classification was used to extract genes involved with apoptosis. Further analysis discovered a subset of differentially expressed genes for further study. RESULTS: Of the 308 apoptotic genes on the microarray filters, 24 genes were predicted to be differentially expressed in lung adenocarcinomas. Alterations in several genes (i.e., Akt, BcL-xL, PTEN, FAS) are consistent with the literature. We also identified 10 novel genes that have not been described in nonsmall cell lung cancer (i.e., RIP, Caspase 1, PDK-1). CONCLUSIONS: These results identified several potential apoptotic genes altered in lung cancer.

Adenocarcinoma↗