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Pramod Bonde

Publications and source records attributed to Pramod Bonde.

12 recordsLinked to original sources
PubMed2006

Selective decrease in the DNA base excision repair pathway in squamous cell cancer of the esophagus.

OBJECTIVES: Oxidative damage can lead to a highly mutagenic 8-oxoguanine lesion, which mispairs with adenosine residues, leading to G:C-->T:A transversions. In mammalian cells 8-oxoguanine glycosylase initiates the DNA base excision repair pathway to repair the 8-oxoguanine lesion. To date, there is no information regarding oxidative DNA damage and repair pathways in esophageal cancer. Therefore we designed the current study to demonstrate the DNA damage and repair pathways in esophageal cancer by expression of 8-oxoguanine glycosylase in reflux-induced and mutagen (methyl-n-amyl nitrosamine)-induced DNA damage and apoptosis in esophageal tumors. METHODS: Gastroduodenal reflux was surgically created in male Sprague Dawley rats (n = 120). Half of the animals received methyl-n-amyl nitrosamine. Animals not undergoing operations served as control animals (n = 10). The experiment concluded 30 weeks postoperatively. Immunohistochemistry for 8-oxoguanine and 8-oxoguanine glycosylase was assessed by 2 independent observers. Protein expression was assessed by using the Western blot method. RESULTS: There was significantly more DNA damage in both adenocarcinoma (n = 15) and squamous cell carcinoma (n = 19), as exemplified by positive 8-oxoguanine expression compared with that seen in control animals (P < .05). 8-Oxoguanine glycosylase was several folds upregulated in adenocarcinoma (P < .05), but there was significantly decreased expression in squamous cell carcinoma (P < .01). The apoptosis was assessed as caspase-dependent and caspase-independent pathways, and both were active and correlated well with 8-oxoguanine expression. CONCLUSION: These results demonstrate the selective decrease in the DNA base excision repair pathway in combined reflux and methyl-n-amyl nitrosamine-induced squamous cell cancer of the esophagus.

Adenocarcinoma↗
PubMed2006

Epidermal growth factor receptor and hedgehog signaling pathways are active in esophageal cancer cells from rat reflux model.

BACKGROUND: Advancements in experimental therapeutics for esophageal cancers have been hampered by the lack of a reliable preclinical model that recapitulates the biology of human cancer, including in vivo growth in an animal model. METHODS: Bilious reflux was induced by esophago-jejunostomy in Sprague-Dawley rats. Nine of 12 (75%) Sprague-Dawley rats developed squamous or adenosquamous cancers, and three cell lines were created by in vitro propagation of freshly resected tumors, JA and JB lines from one cancer, and the AMY cell line from another. We subsequently tested the ability of these cell lines to propagate long-term in vitro and form xenografts in vivo, both hallmarks of transformed cells. In addition, we determined the effects of small molecule inhibitors of two important oncogenic pathways-the epidermal growth factor receptor (EGFR) and Hedgehog (Hh) signaling pathways, in vitro, as a "proof of principle" of using these unique cell lines for developing targeted therapies for esophageal cancer. Mechanism-based growth inhibition was assessed by down-regulation of activated downstream targets of EGFR in the case of Iressa, and by Hh luciferase reporter activity with cyclopamine. RESULTS: JA, JB, and AMY cell lines were able to grow continuously in vitro and consistently form xenografts in vivo in athymic mice, both subcutaneously, as well as in the "orthotopic" location at the gastroesophageal serosal junction (n = 2 mice per line, six of six engrafted). By histology, the tumors grow in vivo as well-differentiated keratinizing squamous cell carcinomas. JB cells had the highest expression of EGFR protein and also the most profound response to Iressa (gefitinib), an EGFR inhibitor (IC50 < 1 microm). Growth inhibition by Iressa was mirrored functionally by down-regulation of activated targets of the EGFR pathway, phospho-ERK1/2 and phospho-MEK levels. AMY cells expressed approximately 900-fold elevation of the Hh ligand, Indian Hh (Ihh), compared with normal esophageal epithelium, whereas expression of another Hh ligand, Sonic Hh (Shh), was not detected. On treatment with the specific Hh small molecule inhibitor cyclopamine, AMY cells demonstrated growth inhibition, which was accompanied by significant down-regulation of endogenous Hh luciferase reporter activity at 24 h and increased apoptosis in treated cells. CONCLUSIONS: We have established a model of esophageal carcinogenesis, capable of long-term in vitro and in vivo passage, and demonstrated therapeutic potential of targeting the EGFR and Hh pathways in the cell lines created from the rodent cancers. These unique cell lines should provide a platform for rapid preclinical validation of novel therapeutics for esophageal cancers.

Animals↗
PubMed2006

Inhibition of TNF-alpha reduces myocardial injury and proinflammatory pathways following ischemia-reperfusion in the dog.

We examined whether tumor necrosis factor-alpha (TNF-alpha) promotes postischemic inflammation and myocardial injury via activation of nuclear factor kappa B (NFkappaB) in an in vivo canine model. Isoflurane-anesthetized dogs underwent closed-chest balloon occlusion of the anterior descending coronary artery for 90 minutes, followed by reperfusion for 3 hours. Dogs randomly received a soluble TNF inhibitor (etanercept, 0.5 mg/kg intravenously) or saline before occlusion. Collateral blood flow and risk region size (RISK) were measured with radioactive microspheres, infarct size (INF) was measured by triphenyltetrazolium chloride staining, inflammation was measured by tissue myeloperoxidase (MPO) activity, intercellular adhesion molecular-1 (ICAM-1) messenger ribonucleic acid (mRNA) was measured by Northern blotting, and ICAM-1 protein expression was measured by Western blotting. NFkappaB activation was measured in nuclear extracts by electrophoretic mobility shift assays. INF/RISK was significantly smaller in the etanercept group than in the saline control group after adjusting for collateral flow (P < 0.009 by analysis of covariance, mean reduction in INF/RISK = 40%, 0.32 +/- 0.09 versus 0.53 +/- 0.09). MPO activity, ICAM-1 mRNA and protein expression, and NFkappaB binding activity were all significantly reduced in the etanercept group. Administration of a soluble TNF-alpha inhibitor reduced NFkappaB activation, ICAM-1 upregulation, and myocardial injury following ischemia-reperfusion. TNF-alpha appears to play a significant role in vivo in the genesis of postischemic inflammation.

Animals↗
PubMed2005

Wound healing enhancement: electroporation to address a classic problem of military medicine.

The major goal of wound healing biology is to determine how a wound can be induced to repair damaged tissue faster and more efficiently. Enhancement of dermal and epidermal regeneration is an extremely important goal for the treatment of many different types of wounds. Exogenous application of growth factors to the wound site has been shown to have potential to improve wound healing. Frequent applications of large amounts of growth factor have been required. This is because proteases in the wound quickly destroy peptide growth factor. Gene therapy has the potential to produce growth factors deep within the wound, where they can be effective as well as able to constantly replenish growth factor that is destroyed by peptidases. We have shown that application of plasmid DNA expression vectors directly into the wound is an inefficient modality. Electroporation, the application of an electrical field across cells to permeabilize the cell membrane has led us to explore the possibility of utilizing the technique to enhance transfection efficiency. We have identified electroporation parameters that improve the efficiency of DNA transfection in cutaneous wounds, and we have shown that electroporation itself does not impair wound healing. We are now on the threshold of exploring whether electroporation-assisted transfection with DNA plasmid expression vectors for growth factors will be an effective modality for enhancing cutaneous wound healing.

Animals↗
PubMed2004

Endoscopic vein harvest: advantages and limitations.

BACKGROUND: Although long saphenous vein remains the most commonly used conduit in coronary revascularization, traditional open vein harvest (OVH) may lead to significantly impaired wound healing and postoperative pain. Endoscopic vein harvest (EVH) attempts to reduce this morbidity and improve patient satisfaction with no compromise in outcome. METHODS: From September 2000 to November 2001, 108 saphenous vein harvests were prospectively randomly assigned to EVH (n = 52) or OVH (n = 56); EVH was performed with the Clearglide endoscopic vein harvest system (Cardiovations) by a single surgeon. Endpoints included impaired wound healing (ASEPSIS score), operative and harvest time, vein quality (including histology), outcome and postoperative pain (Visual Analog Scale). Follow-up was as long as 3 years. RESULTS: The groups were well matched demographically. Endoscopic vein harvest was quicker to perform if sufficient vein for two grafts was needed (p < 0.01). Wound healing was significantly impaired (ASEPSIS score) in the OVH group compared with the EVH group (p < 0.01). The new procedure did not prolong the overall operative time (p = 0.77). Postoperative pain was less (p < 0.01) in the EVH group. Stepwise multiple regression showed age, diabetes, peripheral vascular disease, total operative time, type of procedure, length of incision, and number of vein grafts to be predictive of impaired wound healing. More late interventions were needed in the OVH group for wound-related morbidity. CONCLUSIONS: These data demonstrate that endoscopic vein harvest results in fewer cases of impaired wound healing and reduced postoperative pain, and it does not prolong the operative time significantly nor compromise the vein quality. Furthermore, it is quicker to perform if two grafts are needed, and it reduces late interventions.

Coronary Artery Bypass↗
PubMed2002

Sputum retention after lung operation: prospective, randomized trial shows superiority of prophylactic minitracheostomy in high-risk patients.

BACKGROUND: Sputum retention after lung operation is a potentially life-threatening condition. The minitracheostomy (Minitrach II, SIMS Portex, Hythe, Kent, UK) is a 4-mm percutaneous cricothyroidotomy device, which allows immediate and repeated aspiration of the tracheobronchial tree by minimally trained staff, and can effectively treat sputum retention. This trial was designed to test the hypothesis that prophylactic minitracheostomy could prevent sputum retention in a high-risk group. METHODS: Between March 1997 and October 1999, 102 patients undergoing lung procedures and considered to be at high risk were prospectively randomized to postoperative, prophylactic minitracheostomy insertion in the recovery room with regular aspiration, or to standard postoperative respiratory therapy. RESULTS: Sputum retention developed in 15 patients (30%) in the standard group (n = 52) compared to 1 patient (2%) in the minitracheostomy group (n = 50) (p < 0.005). There were three deaths related to sputum retention in the standard group compared to none in minitracheostomy group during the perioperative period. CONCLUSIONS: It is possible to identify a group of patients at high risk for sputum retention who will benefit from prophylactic therapy. Minitracheostomy is effective as prophylaxis and treatment.

Adult↗
PubMed2002

Lung surgery: identifying the subgroup at risk for sputum retention.

OBJECTIVES: Sputum retention after lung surgery is a potentially lethal condition, which can progress to atelectasis, pneumonia and respiratory failure requiring ventilatory support. Previous studies have concentrated on the treatment of postoperative respiratory complications but few have studied the risk factors for sputum retention. This prospective study was designed to identify the risk factors which may lead to the development of sputum retention after lung surgery. METHODS: Three hundred sixty-one patients underwent lung surgery between January 1997 and December 1999 in a specialist Thoracic Surgery Unit (pneumonectomy, lobectomy, wedge or segmental resection, bullectomy, etc). Preoperative and intraoperative data collected prospectively included potential risk factors: chronic obstructive airway disease (COAD), forced expiratory volume in 1 s (FEV1)<50%, current smokers, ischaemic heart disease (IHD), cerebrovascular disease (CVA), resection of phrenic or recurrent laryngeal nerve, or absence of regional analgesia. Univariate and multivariate analysis was performed. RESULTS: Sputum related complications occurred in 108 patients (30%). There were 17 deaths of which nine were due to complications related to sputum retention. Univariate analysis confirmed current smokers (n=128), COAD (n=103), IHD (n=41), prior history of CVA (n=16), FEV1<50% (n=48), and absence of regional anaesthesia as significant risk factors (P<0.01). The multivariate analysis confirmed current smokers, IHD and absence of regional anaesthesia as risk factors. CONCLUSIONS: A subgroup of lung surgery patients at high risk for postoperative sputum retention can be predicted by the presence of one of the following criteria: current smokers, history of COAD, CVA, or IHD, and absence of regional analgesia. Prophylactic measures should be considered in this group to reduce the incidence of sputum retention.

Aged↗
PubMed2002

Quadricuspid aortic valve: a rare cause of aortic insufficiency.

Quadricuspid aortic valve, a rare congenital cardiovascular anomaly, is an uncommon cause of aortic regurgitation that can be diagnosed accurately with preoperative transesophageal echocardiography. Such a case is presented, and the literature on this topic reviewed.

Aortic Valve↗
PubMed2002

Right atrial myxoma arising from the Eustachian valve in a patient with colonic polyposis.

Right atrial myxoma arising from the Eustachian valve is rare, with only two reported cases; moreover, any association with colonic polyps is uncommon, with only one such case documented. A case is described of a 68-year-old male who presented with chronic anemia; an initial investigation revealed colonic polyps, but anemia persisted after polypectomy. Further investigation revealed a right atrial myxoma arising from the Eustachian valve and prolapsing into the right ventricle through the tricuspid valve. After successful removal of the lesion, hematological indices returned to normal. In cases of persisting anemia, other rare causes such as atrial myxoma should be sought.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Delivery of plasmid DNA expression vector for keratinocyte growth factor-1 using electroporation to improve cutaneous wound healing in a septic rat model.

We have previously shown that wound healing was improved in a diabetic mouse model of impaired wound healing following transfection with keratinocyte growth factor-1 (KGF-1) cDNA. We now extend these findings to the characterization of the effects of DNA plasmid vectors delivered to rats using electroporation (EP) in vivo in a sepsis-based model of impaired wound healing. To assess plasmid transfection and wound healing, gWIZ luciferase and PCDNA3.1/KGF-1 expression vectors were used, respectively. Cutaneous wounds were produced using an 8 mm-punch biopsy in Sprague-Dawley rats in which healing was impaired by cecal ligation-induced sepsis. We used National Institutes of Health image analysis software and histologic assessment to analyze wound closure and found that EP increased expression of gWIZ luciferase vector up to 53-fold compared with transfection without EP (p < 0.001). EP-assisted plasmid transfection was found to be localized to skin. Septic rats had a 4.7 times larger average wound area on day 9 compared with control (p < 0.001). Rats that underwent PCDNA3.1/KGF-1 transfection with EP had 60% smaller wounds on day 12 compared with vector without EP (p < 0.009). Quality of healing with KGF-1 vector plus EP scored 3.0 +/- 0.3 and was significantly better than that of 1.8 +/- 0.3 for treatment with vector alone (p < 0.05). We conclude that both the rate and quality of healing were improved with DNA plasmid expression vector for growth factor delivered with EP to septic rats.

Analysis of Variance↗