Biomedical subjects
Publications and source records attributed to N Rajendran.
Torted appendices are a rare occurrence but should be considered when encountering a haemorrhagic congested appendix on laparoscopy. As adhesions are rarely present, laparoscopic excision is usually a feasible option.
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INTRODUCTION: Tuberculosis peritonitis (TBP) is uncommon and symptoms can be non-specific. Local data are lacking and our aim is to review our local experience with TBP. MATERIALS AND METHODS: Between the period of 1996 to 2004, there were 10 [male: 6; mean age, 48 +/- 18.5 years (range, 26 to 73)] cases of histologically documented TBP. Comparisons were made with pulmonary tuberculosis (PTB) patients. RESULTS: The overall prevalence ranged from 0% to 1.01% of all TB infections. The median duration of symptoms before diagnosis was 2 months (range, 3 days to 24 months). Five patients (50%) had comorbid conditions and 3 patients (30%) had a history of positive contact. Presenting symptoms were abdominal distension (70%), abdominal pain (60%), fever (60%), anorexia (60%) and weight loss (40%). Two patients had pulmonary symptoms: cough/dyspnoea (n = 1) and cough (n = 1). Chest x-ray changes consistent with PTB were seen in 30%. TBP was diagnosed by laparoscopy (n = 6), laparotomy (n = 3) and blind peritoneal biopsy (n = 1). Adverse effects of TB drugs occurred in 80%, consisting of hepatitis (n = 4), nausea/vomiting (n = 2), rash (n = 1) and encephalopathy (n = 1). Haemoglobin (P = 0.026) and serum albumin levels (P = 0.002) were significantly lower in TBP patients. There was a significantly greater number of adverse effects (P <0.001). There were no significant differences between TBP and PTB with regard to age, non-specific symptoms (weight loss, anorexia and fever) and erythrocyte sedimentation rate. All were treated with standard regimes and there were no mortalities. CONCLUSIONS: TBP is uncommon in our population. TBP patients had significantly lower haemoglobin and serum albumin levels. They also experienced more adverse events during treatment. There were no differences in non-specific symptoms between TBP and PTB.
Childhood cognitive and behavioral deficits have been reported in children born to mothers who smoked during pregnancy (Institute of Medicine, 2001). To investigate these potential responses in an animal model, reproductive and neurotoxicity evaluations based on the U.S. FDA guidelines were used to examine the offspring of male and female Sprague-Dawley rats exposed 2 h/day, 7 days/week by nose-only inhalation to whole mainstream smoke total particulate matter (TPM). Concentrations of 150, 300, or 600 mg/m(3) were used (males: 4 weeks prior to and during mating; and females: 2 weeks prior to mating, during mating, and through weaning at postnatal day 21). Sham air controls receiving filtered air and cage controls were also maintained. F(1) rats were weighed, identified by gender, examined for clinical signs of toxicity, and evaluated for neurobehavioral effects through postnatal day 65. Parental exposure was evidenced by smoke concentration-related increases in blood carboxyhemoglobin, nicotine, and cotinine and by characteristic cigarette smoke-related rodent respiratory tract histopathology. Also, nicotine and cotinine were found in F(1) blood through the lactation period. Maternal toxicity occurred at concentrations of 300 and 600 mg TPM/m(3), where total body weight gain during gestation was significantly (p < or = 0.05) decreased compared to sham controls. While smoke concentration-related decreases in F(1) birth weight and growth were evident (600 mg TPM/m(3), significantly different from sham at all time points), no adverse effects on developmental landmarks, including age at vaginal patency or preputial separation, motor activity, acoustic startle response or learning, and memory, were observed in the F(1) generation. This study confirmed that maternal exposure to high levels of mainstream cigarette smoke during gestation and lactation reduces birth weight and retards growth in the rat neonate; however, the developmental and neurobehavioral testing methodologies employed did not appear to be sensitive for an evaluation of neonatal behavioral effects following parental smoke exposure.
The potential developmental effects of 1R4F reference cigarette smoke were examined using Sprague-Dawley rats exposed for 2 h/day, 7 days/week, by nose-only inhalation at target mainstream smoke concentrations of 150, 300, and 600 mg/m3 total particulate matter (TPM). Males were exposed 4 weeks prior to and during mating, with females exposed 2 weeks prior to mating and during mating, and through gestation day (GD) 20. Sham controls received filtered air to simulate nose-only exposure, while cage controls were maintained untreated. Smoke exposure was confirmed through biomarker evaluation (parental: carboxyhemoglobin, nicotine, and cotinine; fetal: nicotine and cotinine). Characteristic cigarette smoke-related histopathologic changes including nasal epithelial hyperplasia and squamous metaplasia and pigmented macrophages in the lung were observed in all exposed parental groups. Maternal toxicity during gestation was indicated at smoke concentrations of 300 and 600 mg TPM/m3, where corrected total body weight gain was significantly (p </= 0.05) decreased compared to sham controls. Food consumption was unaffected. Mating performance was unaffected by exposure: 71-75% pregnant in sham or cage control groups compared to 66-76% pregnant in smoke-exposed groups. Nicotine and cotinine were identified in the blood of fetuses from smoke-exposed dams on GD 20. Resorption rates, litter size, and sex ratio were equivalent among the groups. Fetal body weights at GD 20 were significantly reduced in the group exposed to 300 or 600 mg TPM/m3 compared to sham exposed controls. Developmental abnormalities were rare and sporadic in nature and the absence of a clear smoke concentration relationship suggested they were not related to cigarette smoke inhalation. Skeletal examinations revealed delayed ossification (supra occipital and sternebrae) in fetuses from dams exposed to 300 or 600 mg TPM/m3 smoke. High concentrations of 1R4F cigarette smoke were not teratogenic. The methodology used for this study was able to detect a decrease in fetal birthweight and this approach may be a useful tool for cigarette evaluation.
The growth performance of Rhizophora apiculata Blume (mangrove) seedlings in the presence and absence of exogenous gibberellic acid (GA3) under different combinations of salinity and light was analyzed. Root and shoot growth responses of 75-day old seedlings in liquid-culture, were measured. It was concluded that light exhibited a significant inhibitory effect on all the growth parameters-number of primary roots, primary root length, shoot elongation, number of leaves, total leaf area; and, the GA3 treatment singly or in combinations with light, showed a significant influence on the total leaf area and primary root length.
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Exposure of mangrove seedlings to electric current was studied at an intensity of 10, 20 and 30 mA to 0.5, 1, 3, 6, 12 and 24 h in different combinations, either to plumule or radicle or both parts of the propagules of Rhizophora mucronata Poir (sample size = 30). The electric current-treated propagules and untreated control were cultured hydroponically in sea water for 75 days, and root and shoot growth parameters measured. The root elongation was significantly influenced by duration of exposure, site of propagule treated and combined effects of current intensity x site of propagule treated. Leaf number and area were significantly influenced by intensity of electric current and duration of exposure; whereas shoot elongation was affected by the duration of exposure. The root number was significantly affected by duration of exposure. In general, the electric impulse improved the growth characteristics of shoot and root.
Menthol is a common pharmaceutical, food and tobacco flavouring ingredient used for its minty characteristics and cooling effects. A 13-wk comparative nose-only smoke inhalation toxicity study was conducted using an American-style, cellulose acetate-filtered, non-menthol reference cigarette and a similarly blended test cigarette containing 5000 ppm synthetic l-menthol tobacco. Male and female Fischer 344 rats were exposed for 1 hr/day, 5 days/wk for 13 wk at target mainstream smoke particulate concentrations of 200, 600 or 1200 mg/m3, while control rats were exposed to filtered air. Internal dose biomarkers (blood carboxyhaemoglobin, serum nicotine and serum continine) indicated equivalent exposures were obtained for the two cigarettes. Effects typically noted in rats exposed to high levels of mainstream tobacco smoke were similar for both cigarette types and included reduced body weights (males slightly more affected than females), increased heart-to-body weight ratios and lung weights, and histopathological changes in the respiratory tract. Rats exposed to reference cigarette smoke displayed a dose-related increase in nasal discharge that was not observed in menthol smoke-exposed rats. All smoke-related effects diminished significantly during a 6-wk non-exposure recovery period. The results of this 13-wk smoke inhalation study indicated that the addition of 5000 ppm menthol to tobacco had no substantial effect on the character or extent of the biological responses normally associated with inhalation of mainstream cigarette smoke in rats.
Changes in the viability of Vibrio cholerae 0139 Bengal, estimated by cellular membrane integrity, in batch culture over 35 days, were investigated. Data indicated an initial period of rapid growth with up to 30% of bacterial mortality, followed by a period of slower growth, lower culturability but higher viability, from day 7 onwards. The size of viable bacteria significantly decreased during the incubation time, whilst the size of dead bacteria showed a less pronounced decrease. V. cholerae 0139 changed from a straight or curved rod shape to a spherical shape. This study shows that BacLight dyes are a fast and useful tool to examine health risk-associated bacteria, providing useful information about their viability and concentration.
Mangrove plant extracts were screened in vitro against human immunodeficiency virus (HIV) on MT-4 cells. HIV infected MT-4 cells were cultured for five days in the presence of the extract, at various concentrations. Anti-HIV activity was evaluated by tetrazolium-based colorimetric assay. Seven extracts were found effective. Five of the active extracts completely inhibited the virus adsorption to the cells. Most of the active plants are from the family Rhizophoraceae.
Pseudomonas fluorescens was subjected to insertion mutagenesis studies using the transposon Tn5-GM to generate mutants deficient in antibacterial activity minus mutants. The transposon located on the temperature-sensitive plasmid pCHR84 was conjugally transferred into the non-pathogenic pseudomonad using the triparental mating procedure. Random integration of Tn5-GM into the chromosome of P. fluorescens was achieved by heat treatment of the transformed cells at 42 degrees C. Approximately 2% of transconjugants revealed an auxotrophic phenotype indicating efficient integration of the employed transposon into the chromosome of P. fluorescens. One transposon insertion mutant was obtained showing an antibacterial activity minus phenotype. This mutant (MM-7) was found to be defective in the production of an unidentified antibacterial compound against B. subtilis. These results introduce Tn5 transposon mutagenesis as a new useful tool for the molecular analysis of P. fluorescens.
Twenty-eight sediment samples collected from Osaka Bay, Japan, were analyzed for phospholipid ester-linked fatty acids (PLFA) to determine regional differences in microbial community structure of the bay. The abundance of three major groups of C(10) to C(19) PLFA (saturated, branched, and monounsaturated PLFA), which accounted for 84 to 97% of the total PLFA, indicated the predominance of prokaryotes in the sediment. The distribution of six clusters obtained by similarity analysis in the bay revealed a marked regional distribution in the PLFA profiles. Total PLFA concentrations (0.56 to 2.97 mug/g [dry weight] of the sediment) in sediments also showed marked variation among the stations, with higher concentrations of total PLFA in the central part of the bay. The biomass, calculated on the basis of total PLFA concentration, ranged from 0.25 x 10 to 1.35 x 10 cells per g (dry weight) of the sediment. The relative dominance of microbial groups in sediments was described by using the reported bacterial biomarker fatty acids. Very small amounts of the characteristic PLFA of microeukaryotes in sediments indicated the restricted distribution of microeukaryotes. By examining the distribution of clusters and groups of microorganisms in the bay, there were two characteristics of the distribution pattern: (i) the predominance of anaerobic bacteria and gram-positive prokaryotes, characterized by the high proportions of branched PLFA in the eastern and northeastern sides of the bay, where the reported concentrations of pollutants were also high, and (ii) the predominance of aerobic prokaryotes and eukaryotes, except for a few stations, in the western and southwestern sides of the bay, as evidenced by the large amounts of monounsaturated PLFA. Such significant regional differences in microbial community structure of the bay indicate shifts in microbial community structure.
The distribution of phospholipid ester-linked fatty acids (PLFA) in sediments of eutrophic bays (Hiroshima Bay and Aki Nada) was studied to quantify the microbial biomass, community structure, and nutritional status. A total of 63 fatty acids in the range of C(10) to C(24) were determined. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids, and variation was revealed in the relative proportions of these fatty acids in sediments. On the basis of the PLFA concentration in sediments, the calculated microbial biomass showed variation (mean +/- standard deviation = 0.70 x 10 +/- 0.53 x 10 cells per g [dry weight] of sediment) in the eutrophic bays. In sediments, a higher amount of biomass was observed in the coastal area of Hiroshima Bay than that observed in the rest of the bay and adjacent Aki Nada. The microbial community structure of the present study area, as characterized by the PLFA profiles, showed very low percentages of polyunsaturated fatty acids and long-chain fatty acids characteristic of microeukary-otes and terrestrial input, respectively, and high percentages of fatty acids characteristic of bacteria. The distribution of PLFA profiles also showed the relative contribution of both aerobic and anaerobic bacteria, especially sulfate-reducing bacteria, in the study area. The relative proportions of PLFA revealed distinctive differences among the stations of the study area, as is evidenced from six clusters obtained for the PLFA profiles. The results of Tukey's honestly significant difference test further confirmed that the sediments in the coastal area of Hiroshima Bay were significantly enriched by a number of fatty acids when compared with other areas investigated where relatively few fatty acids were present in significant quantities. No marked variation in environmental parameters in the surface- and bottom-water samples was observed, indicating the absence of any water movement in the study area. Furthermore, low redox potential and the levels of sulfide in the sediment revealed the reduced condition of the sediment. The existing environmental conditions and pollution of the study area were attributed to the observed microbial community structure in the sediments.
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2-Mercaptobenzimidazole (2-MBI), used in rubber processing, is a suspect carcinogen structurally related to ethylene thiourea. The inhalation toxicity of 2-MBI was evaluated in male and female F344/N rats exposed 6 hr/day, 5 days/week to respirable aerosols generated by spray atomization of aqueous suspensions of the 2-MBI powder and subsequent drying of the resulting aerosols. Twelve exposures at target concentrations of 0, 6.3, 12.5, 25.0, 50.0, or 100 mg/m3 of 2-MBI produced a dose-related reduction in body weight gains, thyroid follicular cell hyperplasia, adrenal cortex fatty change, and pituitary atrophy. Sub-chronic exposures were conducted at target concentrations of 0, 3.1, 6.2, 12.5, 25.0, and 50.0 mg/m3 of 2-MBI. Rats at greater than or equal to 25 mg/m3 displayed hunched posture, hypoactivity, and reduced body weight gain, with compound related mortality at the highest exposure level. Anemia; increased SGPT, SGOT, alkaline phosphatase, sorbitol dehydrogenase, BUN, and cholesterol; and reduced free fatty acid were seen in rats at greater than or equal to 25 mg/m3. Increased thyroid weight and thyroid follicular cell hyperplasia were noted in both sexes at greater than or equal to 6.2 mg/m3, with reduced triiodothyronine and thyroxine levels in both sexes at greater than or equal to 12.5 mg/m3. Thyroid follicular cell hyperplasia was also seen in rats at 3.1 mg/m3. Thymus weights were significantly reduced in both sexes at all exposure levels with liver weight increases at greater than or equal to 6.2 mg/m3. Exposure-related histopathologic changes included pituitary cytoplasmic vacuolization, adrenal cortex necrosis, lymphoid depletion, thymic atrophy, liver cell hypertrophy, renal mineralization and tubular atrophy, and hypocellularity of the bone marrow.
A theoretical model is developed for the prediction of the peak to average particle deposition flux in the human bronchial airways. The model involves the determination of the peak flux by a round-nose 2-dimensional bifurcation channel and the average deposition flux by a curved-tube model. The "hot-spot" effect for all generations in the human respiratory system is estimated. It is found that the peak deposition flux is higher than the average deposition flux by a factor ranging between 5 and 30, depending on the generation number. The importance of this peak to average deposition flux ratio on consideration of environmental safety studies is discussed.
Under iron-limiting conditions, Pseudomonas stutzeri KC secretes a small but as yet unidentified factor that transforms carbon tetrachloride (CT) to CO2 and nonvolatile products when activated by reduction at cell membranes. Pseudomonas fluorescens and other cell types activate the factor. Triparental mating was used to generate kanamycin-resistant lux::Tn5 recombinants of strain KC. Recombinants were streaked onto the surface of agar medium plugs in microtiter plates and were then screened for carbon tetrachloride degradation by exposing the plates to gaseous 14C-carbon tetrachloride. CT+ recombinants generated nonvolatile 14C-labeled products, but four CT- recombinants did not generate significant nonvolatile 14C-labeled products and had lost the ability to degrade carbon tetrachloride. When colonies of P. fluorescens were grown next to colonies of CT+ recombinants and were exposed to gaseous 14C-carbon tetrachloride, 14C-labeled products accumulated around the P. fluorescens colonies, indicating that the factor secreted by CT+ colonies had diffused through the agar and become activated. When P. fluorescens was grown next to CT- colonies, little carbon tetrachloride transformation was observed, indicating a lack of active factor. Expression of lux reporter genes in three of the CT- mutants was regulated by added iron and was induced under the same iron-limiting conditions that induce carbon tetrachloride transformation in the wild-type.