Monitoring spatio-temporal dynamics of urban and peri-urban land transitions using ensemble of remote sensing spectral indices-a case study of Chennai Metropolitan Area, India.

Land-use/land-cover change is the most vulnerable factor in any developing urban environment. Increased infrastructure and population density tend to alter the land features which in turn will have an impact on climate change and will increase the impervious layer. Study of trends in land-use/land-cover change is required for analyzing the possible ways of managing the natural system.

Microscopic colitis in children with chronic diarrhea.

Objective: The aim of the present study was to study microscopic colitis (MC) in children with special reference to its role in chronic diarrhea and changes in mucosal biopsies.

Methods: A total of 100 consecutive children ages 3 to 12 years, with nonbloody diarrhea (passage of ≥3 loose stools per day) of >12 weeks' duration were screened and 26 were enrolled in the study in which no specific etiology could be found and colonoscopy did not reveal any mucosal abnormality. Colonic biopsies were evaluated for the presence of lymphocytic colitis or collagenous colitis and those with the characteristic changes were defined to have MC (group A).

Adherent Escherichia coli in colorectal mucosal biopsies: a histological and ultrastructural evaluation.

Background: Colorectal mucosal biopsies occasionally demonstrate the presence of bacteria adherent to the epithelium. This study evaluated the histological and ultrastructural correlates of such bacterial adherence.

Materials And Methods: Rectal mucosal biopsies from eight patients in whom histopathological examination of biopsies had earlier demonstrated adherent bacteria were examined by electron microscopy and by bacterial culture.

Differential expression of enteric neuroimmune-network in invasive and acute watery diarrhoea.

We aimed to evaluate the changes of nerve morphology and distribution of neurotransmitters and neuropeptides in the rectum of Shigella flexneri-infected patients and in the duodenum of Vibrio cholerae O1-infected patients. Nerve morphology was observed by transmission electron microscopy. Immunoreactivity of nerve growth factor (NGF), neurotransmitters and neuropeptides in tissues were studied by immunohistochemistry.

Risk of colorectal cancer in ulcerative colitis in India.

Background: The risk for colorectal cancer (CRC) in ulcerative colitis (UC) in India is not known.

Method: Retrospective cohort from a tertiary level hospital in South India. Analysis of archived records of all patients with UC who underwent colonoscopy and segmental biopsies over the last 25 years.

Effects of zinc supplementation as adjunct therapy on the systemic immune responses in shigellosis.

Background: Zinc is lost during diarrheal diseases, and zinc deficiency induces intestinal morphology-altering inflammatory responses that zinc supplementation can correct.

Objective: We assessed the in vivo effect of zinc supplementation on systemic and mucosal responses in mildly to moderately malnourished (defined as <-1 but >-2 and <-2 but >-3 weight-for-height z scores, respectively, based on the National Center for Health Statistics growth reference) children with shigellosis.

Design: A double-blind placebo-controlled trial was conducted in Shigella flexneri-infected children aged 12-59 mo.

Acute dehydrating disease caused by Vibrio cholerae serogroups O1 and O139 induce increases in innate cells and inflammatory mediators at the mucosal surface of the gut.

Background And Aims: The general concept is that as Vibrio cholerae is not invasive, it mediates a non-inflammatory type of infection. This is being re-evaluated based on available data that natural cholera infection or cholera toxin induces a Th2-type of immune profile and stimulates the humoral immune response, innate cells, and mediators in the host.

Methods: To perform a comprehensive analyses of the inflammatory components, we studied mucosal biopsies from patients, both adults and children with acute watery diarrhoea caused by V cholerae O1 and O139.

Vascular changes in duodenal mucosa in shigellosis and cholera.

Vascular endothelial cells are highly specialized cells with numerous sensory and modulator functions. Our previous studies show extensive microvascular changes in rectal mucosal vasculature of patients with acute infective diarrhea (Mathan and Mathan 1985a, Gut 26:710-717). We looked for changes in the duodenal mucosal vasculature in two naturally occurring diarrheal infections: shigellosis and cholera.

Persistence of mucosal mast cells and eosinophils in Shigella-infected children.

Cells of the innate immune system and their mediators were studied at the single-cell level in the rectums of pediatric and adult patients with Shigella infection to better understand why children are at higher risk for severe infection. Adult patients had increased infiltration of mucosal mast cells (MMC) at the acute stage (3 to 5 days after the onset of diarrhea) and eosinophils in early convalescence (14 to 16 days after onset). Increased expression of stem cell factor and prostaglandin H synthase-1 (PGHS-1) was associated with increased tryptase-K(i)67-double-positive MMC in the acute stage and increased apoptosis of MMC, which led to a rapid decline in early convalescence.

Adaptive and inflammatory immune responses in patients infected with strains of Vibrio parahaemolyticus.

In patients with diarrhea caused by Vibrio parahaemolyticus, antibody-secreting cell responses to thermostable direct hemolysin (TDH), lipopolysaccharide (LPS), and whole-cell bacteria were seen. TDH- and LPS-specific responses were seen in serum samples, and immunoglobulin A antibody responses were observed in stool. Levels of C-reactive protein and nitric oxide metabolites increased in the systemic circulation at the onset of illness.

Cytoskeletal changes during poliovirus infection in an intestinal cell line.

Background & Objectives: Although polioviral replication has been extensively studied, cytoskeletal changes in the host cell during poliovirus replication have not been extensively investigated. We studied the ultrastructural and cytoskeletal changes in host cells during poliovirus infection.

Methods: Fluorescence staining of filamentous actin with a fluorescein-isothiocynate labelled mycotoxin, in the absence and presence of microfilament inhibitors cytochalasins B and D, and electron microscopy were used to investigate the role and fate of actin microfilaments during poliovirus infection, morphogenesis and release in an intestinal cell line, HRT-18.

Increased levels of inflammatory mediators in children and adults infected with Vibrio cholerae O1 and O139.

Investigations were carried out to study the production of factors associated with the innate immune response in the systemic and mucosal compartments in adults and children infected with Vibrio cholerae O1 and V. cholerae O139. The levels of nonspecific mediators of the innate defense system, i.

Epidemiological and laboratory investigations of outbreaks of diarrhoea in rural South India: implications for control of disease.

Two epidemics of acute, watery diarrhoea in villages in North Arcot district, India, were investigated. The attack rates were 10.03 and 15.

Enteroaggregative Escherichia coli infection in a rabbit model.

Type strains of enteroaggregative Escherichia coli EAEC (17-2, serotype O3:H2; JM 221, serotype O92:H33), isolates from an adult and a child with diarrhoea and an asymptomatic colonised child were used to orally infect adult rabbits. The experimental animals were followed up and sacrificed at defined time periods. Colonisation of both small and large intestine was seen with all strains and isolates used.

A monkey model for enterohemorrhagic Escherichia coli infection.

Adult Macaca radiata (n=22) were infected intragastrically with 10(12) Escherichia coli O157:H7 strain 84-01, which produces Shiga toxins 1 and 2. Clinical symptoms and bacterial excretion were documented in each monkey for a specified time period before they were killed. At necropsy, samples were obtained for culture and histologic and ultrastructural examination.

A prospective study of nosocomial enteric pathogen acquisition in hospitalized children in South India.

Screening for enteric pathogens in stool samples from 249 children under the age of 36 months, admitted to hospital for non-gastrointestinal disorders, was positive at admission in 41 (16.4 per cent) in a prospective study of enteric pathogen acquisition and diarrhoea in hospitalized children. Infection with multiple organisms was found in 31/41 (75.

Glomerular injury induced in mice by intraperitoneal injection of Shiga-like toxins.

Background And Objectives: Shiga-like toxins I and II (Stx1 and Stx2) play an important role in the pathogenesis of renal disease by causing renal microvascular injury. A murine model was used to study glomerular lesions produced by Stx1 and Stx2.

Methods: Swiss albino mice of the Rockefeller strain were inoculated intraperitoneally with LD(50) doses of endotoxin-free Stx1 of Stx2 and observed for signs of disease.

Innate immune responses in children and adults with Shigellosis.

An array of pro- and anti-inflammatory mediators of the innate immune system was analyzed in stool, urine, and rectal mucosa samples from adults and children with shigellosis to better understand their role in recovery from and in the immunopathogenesis of the disease. Increased concentrations of lactoferrin (Lf), myeloperoxidase (MPO), prostaglandin E(2), and leukotriene B(4) (LTB(4)) in stool during acute shigellosis in both children and adults indicated that activated cells of the innate defense system at the mucosal site were secreting the mediators. Increased concentration of MPO and 8-iso-prostaglandin F(2alpha) and lower levels of superoxide dismutase (SOD) activity in stool during acute Shigella infection suggested increased formation of reactive oxygen species, free radical-catalyzed peroxidation of membrane lipids, and decreased scavenging of the reactive oxygen radicals.

Butyrate and glucose metabolism by colonocytes in experimental colitis in mice.

Background/aims: Impaired colonocyte metabolism of butyrate has been implicated in the aetiopathogenesis of ulcerative colitis. Colonocyte butyrate metabolism was investigated in experimental colitis in mice.

Methods: Colitis was induced in Swiss outbred white mice by oral administration of 4% dextran sulphate sodium (DSS).

Use of serology, the urease test & histology in diagnosis of Helicobacter pylori infection in symptomatic & asymptomatic Indians.

Age-specific prevalence of IgA and IgG antibodies in 714 subjects without gastrointestinal complaints aged 6 months to 90 yr was measured by an enzyme linked immunoassay using an acid-glycine extract of H. pylori as the antigen. The urease test and histology were used for the diagnosis of H.

Prevalence of enteroaggregative and other HEp-2 cell adherent Escherichia coli in asymptomatic rural south Indians by longitudinal sampling.

Enteroaggregative and other HEp-2 cell adherent Escherichia coli can produce acute and persistent diarrhoea in children and adults, but their prevalence in asymptomatic individuals in the community is not known. In this study, faecal specimens were obtained at 3-4 monthly intervals from 349 subjects constituting a 20% age-stratified sample of a rural community for a period of two years. HEp-2 cell adherent E.

Cytomegalovirus infection of the human gastrointestinal tract.

Background: Current interest in cytomegalovirus (CMV) is largely due to an increase in the number of cases of acquired immunodeficiency syndrome and organ transplantation in recent years. The proper recognition of CMV-infected cells in gastrointestinal mucosal biopsies is critical for effective treatment of this condition.

Methods: A total of 6580 endoscopic mucosal biopsies from 6323 patients in the 8-year period (1989-1996) were examined for CMV inclusion bodies.

Effect of shiga toxin on NaCl transport in rat distal colon.

Background: Shiga toxin causes net fluid secretion in rabbit jejunum by selectively targeting, and inhibiting protein synthesis in, absorptive villous cells. The effect of Shiga toxin on the colon, where it is presumably produced, is not known. This study was undertaken to investigate the effect of Shiga toxin on the rat distal colon.

Enteric pathogens in southern Indian HIV-infected patients with & without diarrhoea.

This study was undertaken to determine the carriage rate of various enteric pathogens in southern Indian patients with HIV infection, both with and without diarrhoea. Stool from 111 consecutive HIV-positive patients (50 without and 61 with diarrhoea) was examined by microscopy and culture. Jejunal biopsy and fluid examination were carried out if diarrhoea persisted, with negative stool examination.

Endoscopic mucosal biopsies are useful in distinguishing granulomatous colitis due to Crohn's disease from tuberculosis.

Background: Intestinal tuberculosis and Crohn's disease are chronic granulomatous disorders that are difficult to differentiate histologically.

Aims: To characterise distinctive diagnostic features of tuberculosis and Crohn's disease in mucosal biopsy specimens obtained at colonoscopy.

Methods: Selected histological parameters were evaluated retrospectively in a total of 61 biopsy sites from 20 patients with tuberculosis and 112 biopsy sites from 20 patients with Crohn's disease.