Biomedical subjects

A Gautam

Publications and source records attributed to A Gautam.

At least 19 recordsLinked to original sources

PubMed2004

Keeping up with the Jones's: open donor nephrectomy in the laparoscopic era.

Several new approaches have been developed to perform donor nephrectomy. These include laparoscopic donor nephrectomy and open donor nephrectomy performed through small incisions, herein referred to as "mini-open donor nephrectomy". In the past, we performed open donor nephrectomy via a standard flank incision. In October 2002, we introduced mini-open donor nephrectomy via an anterior, retroperitoneal approach. Contemporaneously, we offered the option of laparoscopic donor nephrectomy. Herein, we review our single-center experience with these three techniques. Mini-open donor nephrectomy was comparable to the laparoscopic approach for duration of narcotic requirement and donor length of stay. The laparoscopic procedure was more expensive. Both procedures demonstrated improvement over the flank approach by eliminating the risk of pneumothorax, neuropathy, and flank bulge. In addition, length of stay and narcotic requirements were higher with the flank approach. Mini-open donor nephrectomy provides a good alternative to laparoscopic surgery, offering the donor an equivalent convalescence at lower cost and potentially with reduced morbidity.

Adult↗

PubMed2004

Enteric perforation--single-layer closure.

A hundred cases of enteric perforation, treated surgically by single- or double-layer closure, were studied prospectively. Mortality and morbidity rates were 10-18 and 37-42% and comparable in the two groups. The presence of preoperative shock was the single most important prognostic indicator observed in this study. Hence it is good closure of the perforation rather than single- or double-layer closure that determines the outcome in patients with enteric perforation.

Adolescent↗

PubMed2003

Gangrenous sigmoid volvulus: a clinical study of 76 patients.

BACKGROUND AND AIMS: This study investigated the clinical picture of gangrenous sigmoid volvulus presented by Indian patients to describe the various patterns of gangrene and to identify the risk factors leading to the very high mortality from this disease. PATIENTS AND METHODS: A structured protocol including nine parameters was used to study risk factors in 76 patients treated at two major teaching hospitals in India. The clinical picture of patients at the two hospitals did not differ significantly. RESULTS: Contrary to expectations, we found gangrene in 26% of cases extending beyond the area of constriction into the rectum/descending colon. This extension was sometimes patchy and had an ill defined line of demarcation, which may lead to an error in judgment and cause a failure of anastomosis, which can be fatal. Risk factors were age over 60 years, the presence of shock on admission and a history of previous episodes of volvulus. CONCLUSION: This study identified three risks for survival. It is suggested that all patients with nongangrenous sigmoid volvulus undergo a recurrence-prevention procedure immediately or electively. We also found that extension of gangrene beyond the confines of the constriction is not uncommon, calling for caution on the part of the treating surgeon.

Adolescent↗

PubMed2003

Clostridium innocuum bacteremia secondary to infected hematoma with gas formation in a kidney transplant recipient.

Clostridium innocuum is a relatively antimicrobial resistant, frequently misidentified anaerobe that has only rarely been associated with bacteremia. A 38-year-old female with chronic hepatitis C underwent a second kidney transplant operation. Two weeks after surgery a computed tomography scan of the abdomen showed a heterogeneous hematoma with pockets of gas adjacent to the allograft, which extended into the pelvis and left abdominal wall, associated with low-grade fever. An anaerobic blood culture grew a Clostridium initially identified as C. subterminale and later re-identified as C. innocuum. At abdominal exploration liquefied blood was evacuated, and the patient completed a course of antibiotics and recovered. C. innocuum should be considered as a cause of gas-producing anaerobic infection in transplant patients. Because C. innocuum is frequently misidentified by the use of commercial anaerobic identification kits, its true incidence in serious infections is likely underestimated.

Adult↗

PubMed2002

Growth inhibition of established B16-F10 lung metastases by sequential aerosol delivery of p53 gene and 9-nitrocamptothecin.

Growth inhibition of established tumor metastases in the lungs poses a difficult challenge for most clinical settings in spite of extensive multi-modality approaches. Aerosol delivery of drugs and genes holds promise for the treatment of disseminated lung metastases, since aerosol delivery can target the lungs specifically and uniformly. We previously demonstrated that aerosol delivery of dilauroylphosphatidylcholine liposome formulation of 9-nitrocamptothecin (9NC-DLPC) inhibits B16-F10 melanoma lung metastases. Aerosol delivery of polyethleneimine-p53 DNA (PEI-p53) complexes results in a similar anti-tumor effect in the B16-F10 model. In both these previous studies, the protocols were designed to inhibit development of lung metastases. In this study we demonstrate, using the B16-F10 melanoma lung metastasis model, that sequential aerosol delivery of PEI-p53 and 9NC-DLPC acts additively to inhibit growth of established B16-F10 tumor metastases in the lungs. Mice injected with B16-F10 cells and treated with a combination of 9NC-DLPC (twice weekly) and PEI-p53 (once weekly) aerosol complexes starting on day 11 after tumor inoculation, exhibited a highly significant (P < 0.01) reduction in the number of visible tumor foci as compared with untreated mice or mice treated with either single agent alone, or with a combination of 9NC and a control plasmid. There was a highly significant reduction in the tumor burden, as well as the lung weights for the 9NC and p53 combination group (P < 0.001 as compared with other groups). Moreover, the doses of p53 gene and 9NC in the combination group were reduced at least two-fold as compared with our previous single agent studies, but still achieved significant tumor inhibition. Furthermore, the sequential aerosol delivery of p53 and 9NC lead to a 30-40% increase in the mean survival time of these mice, as compared with animals in different control groups. The data suggest that the combination of 9NC and p53 gene delivered by aerosol is an attractive strategy for growth inhibition of established tumor metastases in the lungs.

Aerosols↗

PubMed2002

Gene delivery to the lung using protein/polyethylenimine/plasmid complexes.

Delivery of genes to the lung has enormous potential in a wide variety of illnesses, from lung cancer to genetic deficiency diseases. Many delivery systems have been utilized, each with its own advantages and limitations. Polyethylenimine is a polycation capable of binding and compacting DNA, enabling intravascular plasmid delivery to normal tissues in such a way that the plasmid can be expressed in a proportion of the exposed cells. We have developed a novel intravenous method to deliver small amounts of plasmid to lung tissue, using nontoxic quantities of polyethylenimine in combination with albumin (or other soluble proteins). Injection of 1 microg or less of plasmid resulted in highly efficient gene expression in lung interstitial and endothelial tissues (0.5 to 1 ng luciferase per microg plasmid DNA), while larger quantities of plasmid reduced relative gene expression. Using luciferase as a reporter gene, single injections had maximal gene expression between 24 and 48 h, with a rapid decline thereafter. In contrast to some other delivery systems, however, no inhibition of gene expression occurred during multiple rounds of plasmid administration through 20 days. As a result, this method may have useful applications in diseases that could benefit from recurrent therapeutic gene delivery.

Animals↗

PubMed2001

Active vaccination against IL-5 bypasses immunological tolerance and ameliorates experimental asthma.

Current therapeutic approaches to asthma have had limited impact on the clinical management and resolution of this disorder. By using a novel vaccine strategy targeting the inflammatory cytokine IL-5, we have ameliorated hallmark features of asthma in mouse models. Delivery of a DNA vaccine encoding murine IL-5 modified to contain a promiscuous foreign Th epitope bypasses B cell tolerance to IL-5 and induces neutralizing polyclonal anti-IL-5 Abs. Active vaccination against IL-5 reduces airways inflammation and prevents the development of eosinophilia, both hallmark features of asthma in animal models and humans. The reduced numbers of inflammatory T cells and eosinophils in the lung also result in a marked reduction of Th2 cytokine levels. Th-modified IL-5 DNA vaccination reduces the expression of IL-5 and IL-4 by approximately 50% in the airways of allergen-challenged mice. Most importantly, Th-modified IL-5 DNA vaccination restores normal bronchial hyperresponsiveness to beta-methacholine. Active vaccination against IL-5 reduces key pathological events associated with asthma, such as Th2 cytokine production, airways inflammation, and hyperresponsiveness, and thus represents a novel therapeutic approach for the treatment of asthma and other allergic conditions.

Animals↗

PubMed2001

A single domain of the replication termination protein of Bacillus subtilis is involved in arresting both DnaB helicase and RNA polymerase.

The current models that have been proposed to explain the mechanism of replication termination are (i) passive arrest of a replication fork by the terminus (Ter) DNA-terminator protein complex that impedes the replication fork and the replicative helicase in a polar fashion and (ii) an active barrier model in which the Ter-terminator protein complex arrests a fork not only by DNA-protein interaction but also by mechanistically significant terminator protein-helicase interaction. Despite the existence of some evidence supporting in vitro interaction between the replication terminator protein (RTP) and DnaB helicase, there has been continuing debate in the literature questioning the validity of the protein-protein interaction model. The objective of the present work was two-fold: (i) to reexamine the question of RTP-DnaB interaction by additional techniques and different mutant forms of RTP, and (ii) to investigate if a common domain of RTP is involved in the arrest of both helicase and RNA polymerase. The results validate and confirm the RTP-DnaB interaction in vitro and suggest a critical role for this interaction in replication fork arrest. The results also show that the Tyr(33) residue of RTP plays a critical role both in the arrest of helicase and RNA polymerase.

Azides↗

PubMed2001

Transgene expression in mouse airway epithelium by aerosol gene therapy with PEI-DNA complexes.

Gene therapy targeted at the respiratory epithelium holds therapeutic potential for diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency. A variety of approaches such as intranasal or intratracheal instillation and aerosol delivery have been utilized to target genes to the airways. Polyethylenimine (PEI), a linear or branched polycationic polymer, has been used for delivery of genes to various organs. In this study, using fluorescein isothiocyanate (FITC)-labeled branched PEI, we initially examined the localization of PEI in the lungs after aerosol delivery to Balb/C mice. Further, after aerosol delivery of PEI-CAT DNA, in situ immunostaining for chloramphenicol acetyl transferase (CAT) protein was used to localize the transgene expression within the lungs. Immunohistochemistry for CAT, as well as localization of FITC-labeled PEI, revealed that after aerosol delivery, the PEI-DNA complexes deposit and subsequently transfect most of the epithelial cells in the conducting airways (including the peripheral airways). High levels of CAT were detected at 24 h after aerosol exposure and significant CAT expression was detected in the lungs up to 28 days after a single aerosol exposure. The data suggest that aerosol delivery of PEI-DNA complexes could be effective for the treatment of pulmonary diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency.

Administration, Inhalation↗

PubMed2001

Carcinoma of the gallbladder: a retrospective review of 99 cases.

Since the first description of the carcinoma of the gallbladder, about two centuries ago, this disease has evaded all attempts at early detection and a potential cure. There are only a few studies involving the Indian population, which has a high incidence of gallbladder cancer. Indians are ethnically and culturally different from their Western counterparts, for whom the incidence of this disease is comparatively low. The present study was conducted prospectively on 99 consecutive cases of carcinoma of the gallbladder of 736 patients with biliary diseases admitted to one surgical unit at the University Hospital. The staging, histological type, and grade were correlated with the clinical outcome. Abdominal pain (82.8%) and abdominal mass (73.7%) were the main presenting features. The diagnosis was obtained by ultrasonography (USG) in 93 of 99 cases and confirmed by fine-needle aspiration cytology (FNAC) in 70 patients. Ultrasonography, however, was found to be inadequate for accurate staging of the disease. Based on the TNM classification, 3 (3.0%), 12 (12.1%), 14 (14.1%), 12 (12.1%), and 58 (58.6%) patients had stage 0, I, II, III, and IV disease, with a corresponding mean survival of 28.3, 13.8, 7.5, 5.2, and 3.7 months, respectively. Carcinoma of the gallbladder is difficult to diagnose early due to its vague symptomatology. A high index of suspicion and health education seem to be the only answers available for early detection and improvement of survival.

Adenocarcinoma↗

PubMed2001

Growth suppression of established human osteosarcoma lung metastases in mice by aerosol gene therapy with PEI-p53 complexes.

Lung metastases are a frequent complication of osteosarcoma and a treatment that would reduce the severity of this complication would be of great benefit to patients. We have used a formulation consisting of polyethyleneimine (PEI) and a p53 gene administered in aerosol to treat established lung micrometastases as a model of human osteosarcoma in nude mice. The SAOS-LM6 cell line, a metastatic derivative of the p53 null SAOS-2 line, expresses high levels of p53 protein after in vitro transfection with PEI-p53 complexes as determined by ELISA, and transfection with both p53wt and the p53 variant, p53-CD(1-366) in vitro, results in a marked inhibition of SAOS-LM6 cell proliferation. Aerosol delivery of plasmid DNA containing either the p53 gene or a p53-CD(1-366) variant gene formulated with PEI to mice resulted in highly significant reductions in the numbers and size of tumors (P<.001), the total number of tumor foci in the lungs (P<.001) and the size of individual tumor nodules in treated animals compared to untreated, PEI only-treated and PEI-CAT-treated control animals. The different tissues examined did not reveal any signs of toxicity or inflammation after repeated exposure to PEI-DNA. The aerosol delivery of PEI-based formulations of p53 or synthetic p53 variant genes represents a promising new strategy for the treatment of established human osteosarcoma lung metastases. The noninvasive nature of aerosol delivery coupled with low toxicity also make this therapeutic approach potentially appropriate for combination therapy with either radio- or chemotherapy.

Administration, Inhalation↗

PubMed2001

Pulmonary cytokine responses associated with PEI-DNA aerosol gene therapy.

Pulmonary gene therapy with nonviral vectors delivered by instillation or intravenously has typically been associated with co-induction of cytokine responses attributed to the CpG motifs in the bacterial plasmid. Alternative delivery systems are being developed to circumvent the cytokine responses to the plasmid. Aerosol delivery of polyethylenimine--DNA (PEI-DNA) complexes leads to localized, high levels of transgene expression in the lungs. In this study, we show that PEI-DNA aerosol delivery is also associated with induction of tumor necrosis factor alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) in the lung and bronchoalveolar lavage fluid (BALF). However, there is no increase in the serum levels of these cytokines. The levels of these cytokines peak at 5--8 h after aerosol exposure for lung tissue, and at 24 h for BALF. However, the levels detected are much lower than those observed when PEI-DNA complexes, guanidinium--cholesterol: dioleoylphosphatidyl--ethanolamine liposome--DNA (BGTC:DOPE--DNA) complexes or 1,2-dioleoyl-sn-glycero-3-trimethylammonium--propane--cholesterol:DNA (DOTAP-Chol:DNA) complexes were delivered intravenously. Also, the lung cytokine levels were higher when BGTC:DOPE--DNA complexes were delivered by aerosol to the mice. Although the mechanism remains to be elucidated, the data suggest that aerosol exposure to PEI--DNA complexes can achieve high levels of transgene expression in the lungs without inducing high levels of cytokine responses.

Administration, Inhalation↗

PubMed2000

A replication terminus located at or near a replication checkpoint of Bacillus subtilis functions independently of stringent control.

We have examined a replication terminus (psiL1) located on the left arm of the chromosome of Bacillus subtilis and within the yxcC gene and at or near the left replication checkpoint that is activated under stringent conditions. The psiL1 sequence appears to bind to two dimers of the replication terminator protein (RTP) rather weakly and seems to possess overlapping core and auxiliary sites that have some sequence similarities with normal Ter sites. Surprisingly, the asymmetrical, isolated psiL1 site arrested replication forks in vivo in both orientations and independent of stringent control. In vitro, the sequence arrested DnaB helicase in both orientations, albeit more weakly than the normal Ter1 terminus. The key points of mechanistic interest that emerge from the present work are: (i) strong binding of a Ter (psiL1) sequence to RTP did not appear to be essential for fork arrest and (ii) polarity of fork arrest could not be correlated in this case with just symmetrical protein-DNA interaction at the core and auxiliary sites of psiL1. On the basis of the result it would appear that the weak RTP-L1Ter interaction cannot by itself account for fork arrest, thus suggesting a role for DnaB-RTP interaction.

Bacillus subtilis↗

PubMed2000

Enhanced gene expression in mouse lung after PEI-DNA aerosol delivery.

Aerosol gene delivery to the pulmonary system has vast potential for many diseases, including cystic fibrosis and lung cancer. We recently reported that polyethyleneimine (PEI), a cationic polymer, holds promise as a gene delivery vector for transfection in lung by aerosol. To further optimize the gene expression in the lung by aerosol, we utilized 5% CO(2) in air for the nebulization of PEI-DNA complexes. Five percent CO(2)-in-air gave a threefold higher gene expression compared to normal air using the chloramphenicol acetyl transferase (CAT) reporter gene delivered by Aerotech II nebulizer. The delivery of DNA by PEI was dose dependent with the highest expression obtained when 2 mg of DNA in 10 ml was nebulized at a PEI nitrogen:DNA phosphate (N:P) ratio of 10:1. The optimal N:P ratio for lung transfection was found to be between 10:1 and 20:1 using the CAT and luciferase reporter genes. The time-course studies showed the highest expression at 24 h after aerosol delivery and 40-50% of peak level was detectable even after a week. Tissue distribution indicates the expression to be specific to the lung with no detectable expression in any other tissue examined. Histological and biochemical analysis of lungs revealed no evidence of acute inflammation.

Aerosols↗

PubMed2000

Inhibition of experimental lung metastasis by aerosol delivery of PEI-p53 complexes.

Mutations in the p53 tumor suppressor gene and the pathways mediated by the p53 protein are common in many human cancers. Replacement of functional p53 by gene therapy is a potential way of combating these cancers and the associated drug resistance and tumor growth. Aerosol delivery of genes is a noninvasive way of targeting genes to the lung for gene therapy. Here we demonstrate, using a murine melanoma lung metastasis model, that aerosol delivery of polyethyleneimine-p53 (PEI-p53) complexes inhibits the growth of lung metastasis. A significantly reduced number of visible foci were observed in C57BL/6 mice injected with B16-F10 melanoma and treated with PEI-p53 complexes by aerosol for 3 weeks at twice a week. Fifty percent of the mice in the PEI-p53-treated group exhibited no visible tumor foci. There was a significant reduction in the lung weights of p53-treated mice (P < 0.01) compared to control groups. The tumor burden was also significantly lower (P < 0.001) in mice treated with PEI-p53 complexes. No extrapulmonary metastasis was observed in the groups treated with PEI-p53 complexes compared to 50% of the mice in control groups, which showed metastasis to lymph nodes in the neck or abdomen. Treatment with PEI-p53 aerosol also led to about a 50% increase in the mean length of survival of the mice injected with B16-F10 cells. These data suggest that delivery of the p53 gene by aerosol using PEI as the gene delivery vector can inhibit the growth of lung metastasis.

Administration, Inhalation↗

PubMed1999

Malignancy load on general surgeons: the need to change the general surgical training curriculum.

AIMS: With the advent of newer diagnostic modalities more and more cancer patients are being diagnosed each year. The rising detection rate and greater public awareness have immensely increased the load on already overburdened and increasingly fewer surgical oncology units. As a result a large number of these cases are being dealt with by general surgeons. METHODS: We have used a retrospective case count from a single surgical unit, based at the University Hospital, Varanasi, and data from the Hospital Based Cancer Registry (HBCR), Regional Cancer Centre (RCC), Trivandrum, from 1990 to 1994, to define the malignancy load on general surgical units and to define the number and sites of malignancies commonly encountered by general surgeons. RESULTS: A total of 28,136 patients were registered at the RCC, the commonest malignancy being oral cavity (16.35%), followed by lung (12.7%) and breast (23.8%) among men and women, respectively. On the other hand, in the 2123 patients with malignancy who were treated at the Medical College (MCH) in Trivandrum, the commonest sites encountered were stomach (11.68%), thyroid (10.31%) and colorectal (9.5%). This was quite similar to the frequencies observed at Varanasi, where colorectal cancer constituted 10.26% and stomach 6.98%. Only 13.6% of the patients reporting to RCC were treated by surgery alone or in combination, while this figure was 48. 1% for MCH. Similarly 2056 (7.3%) patients presenting to RCC had completed treatment prior to being referred to RCC; almost all of these patients were treated by surgery at referral institutions by general surgeons. CONCLUSIONS: The results clearly indicate an increased demand on the surgical oncology units, or alternatively an urgent need to redefine the postgraduate curriculum for the better training of general surgeons in understanding malignant disease, especially in the developing countries. We recommend a minimum of 6 months training in surgical oncology for each general surgery postgraduate.

Cancer Care Facilities↗

PubMed1998

Erythrocyte membrane stearic to oleic acid ratio in carcinoma of the gallbladder: a preliminary study.

AIMS: The role of erythrocyte membrane stearic to oleic acid ratio (saturation index) as a marker of malignancy is still unclear, though an association has been found in colorectal carcinoma, bronchogenic carcinoma, leukaemia, lymphoma and in hepatic malignancies. This study aims to investigate the role of the saturation index in primary carcinoma of the gallbladder. METHODS: This paper describes the results of the stearic to oleic acid ratio determination in 26 subjects with either cholelithiasis or carcinoma of the gallbladder, also including a group of age- and sex-matched controls, using gas chromatography. This is the first report of the saturation index in carcinoma of the gallbladder. RESULTS: A significantly lower saturation index was observed in patients with carcinoma of the gallbladder than with cholelithiasis (t = 2.19, P = 0.043, T = 47, P < 0.05, Wilcoxon P < 0.001, F = 2192.23, P < 0.001; 95% CI 18.45-30.44) and controls (t = 2.5, P = 0.024, T = 36, P < 0.05, F = 10904.11, P < 0.001, Wilcoxon P < 0.001; 95% CI 52.42-63.39). Among the carcinoma patients a further lowering was noted in stage IV disease compared with stage III (T = 6, P < 0.05). CONCLUSIONS: These changes are probably due to a marked increase in oleic acid content at the expense of stearic acid. This lowering of the saturation index in carcinoma of the gallbladder is similar to that observed previously in the other malignancies.

Carcinoma↗

PubMed1998

Carcinoma of the gallbladder presenting as scalp tumour.

Carcinoma of the gallbladder is characterized by rapid tumour growth associated with lymphatic and local tumour invasion. The peritoneum, GIT and lungs are common sites of seeding. Distant metastasis to bone rarely occurs. Here we document a case of silent gallbladder carcinoma presenting as scalp tumour with improved survival.

Carcinoma↗