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Biomedical subjects

A Gautam

Publications and source records attributed to A Gautam.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

Xanthogranulomatous cholecystitis.

Xanthogranulomatous cholecystitis exists in a small but significant proportion of routine cholecystectomy specimens. A few recent reports have shown a possible association of this disease with carcinoma of the gallbladder. All cholecystectomized specimens were prospectively evaluated over a period of two and half years in a single surgical unit to examine the incidence of xanthogranulomatous cholecystitis and its association, if any, with carcinoma of the gallbladder in an area that is prone to gallbladder diseases. A total of 460 cholecystectomies were performed for various gallbladder diseases. Histological confirmation revealed chronic cholecystitis in 311 (67.6%) cases, carcinoma of the gallbladder in 62 (13.5%), acute cholecystitis in 29 (6.3%), xanthogranulomatous cholecystitis in 41 (8.9%), and xanthogranuloma and carcinoma of the gallbladder in one case (0.2%) only. Almost all cases were suspected to have chronic cholecystitis on clinical and ultrasonographic features. Two specimens on gross examination showed mass lesions, and hence were suspected to be carcinoma of the gallbladder. Subsequent frozen section and histopathology demonstrated xanthogranulomatous cholecystitis. Only one case of xanthogranuloma was found to be associated with carcinoma of the gallbladder but no firm association could be established between xanthogranulomatous cholecystitis and carcinoma of the gallbladder.

Acute Disease↗
PubMed1998

Metallothionein expression in carcinoma of the gallbladder.

AIMS: Metallothioneins (MT) are sulphur-rich, low molecular-weight, intracellular metal-binding proteins with a possible role in carcinogenesis of some human tumours. Metallothionein expression in gallbladder cancer has not been studied previously. METHODS AND RESULTS: Immunohistochemical expression of metallothionein was studied in 42 gallbladders (27 cases of carcinoma of the gallbladder, eight chronic cholecystitis and seven cases of normal gallbladder). Metallothionein expression was significantly higher in cases with carcinoma of the gallbladder (70.37%) as compared to chronic cholecystitis (25%) and normal gallbladders (0%). There was a trend suggestive of increasing MT expression with increasing histological dedifferentiation of carcinoma of the gallbladder. CONCLUSIONS: The increased expression of MT in cases of carcinoma of the gallbladder may represent an increased exposure to heavy metals, which are known carcinogens, and may have a role in gallbladder carcinogenesis. Metallothionein over-expression in carcinoma of the gallbladder may be relevant to the poor prognosis and chemoresistance seen in these cases.

Adult↗
PubMed1998

Cardiff repair of incisional hernia: a university hospital experience.

OBJECTIVE: To analyse our results of the "Cardiff' (far and near) repair in incisional hernias. DESIGN: Prospective study. SETTING: University hospital, Varanasi, India. SUBJECTS: 50 patients who presented with incisional hernias between January 1990 and December 1994. INTERVENTION: Interrupted far-and-near sutures inserted after excision of the sac. The contents were pushed into the abdomen and the peritoneum sutured with non-absorbable polypropylene (prolene). MAIN OUTCOME MEASURES: Early and late morbidity. Six patients developed postoperative complications (wound infection, n=3; flap necrosis, n=2; and wound sinus, n=1). No patient has been lost to follow up and there have been no signs of recurrence after a mean follow up of 52 months. CONCLUSION: The meticulous application of this simple surgical technique has low morbidity and is cost effective. We recommend it for small and medium size defects.

Adolescent↗
PubMed1996

Quantitative analysis of peptides from myelin basic protein binding to the MHC class II protein, I-Au, which confers susceptibility to experimental allergic encephalomyelitis.

BACKGROUND: An important issue in autoimmune diseases mediated by T cells, such as experimental allergic encephalomyelitis (EAE), is the affinity of the disease-inducing determinants for MHC class II proteins. Tolerance, either due to clonal deletion or anergy induction, is thought to require high-affinity interactions between peptides and MHC molecules. Low-affinity binding is compatible with the hypothesis that breaking tolerance to self proteins does not have to occur for onset of disease. In contrast, a high-affinity interaction implies that an event leading to a breakdown of tolerance is central to the autoimmune process. MATERIALS AND METHODS: Detergent-solubilized and affinity-purified I-Au was incubated with varying concentrations of a set of peptides from myelin basic protein and a biotinylated peptide agonist. The specific complexes were separated from excess peptide by capture on antibody-coated plates, and the affinity of the peptides was measured by adding europium-labeled streptavidin and measuring the resultant fluorescence. RESULTS: The immunodominant and encephalitogenic determinant, Ac 1-11, was shown to bind to I-Au relatively poorly (IC50 = 100 microM), demonstrating that in this protein, immunodominance did not correlate with high-affinity binding. In contrast with the natural sequence, the ability of shorter analogs to induce EAE did correlate with their apparent affinity. CONCLUSIONS: The dominance of the natural determinant does not arise from a high-affinity interaction with the MHC class II molecule. This suggests that other mechanisms are operative and that the specific T cell for this peptide/MHC ligand is of high affinity.

Amino Acid Sequence↗
PubMed1995

Erythrocyte membrane fatty acid profile in patients with primary carcinoma of the gallbladder.

Erythrocyte fatty acids were determined in patients with gall stones and carcinoma of the gallbladder. Significantly low levels of myristic acid (P < 0.01) and stearic acid (P < 0.001) and significantly high levels of palmitoleic acid (P < 0.05) and oleic acid (P < 0.01) were observed in cancer patients. Arachidonic and linolenic acid were significantly high in gallstone patients, but there was no significant difference in the lauric acid and palmitic acid levels. Thus an altered lipid metabolism in cancer patients suggest existence of a possible association between gallstones, fatty acids, and carcinoma of the gallbladder.

Cholelithiasis↗