Synthesis, characterization and antimicrobial activity of dextran stabilized silver nanoparticles in aqueous medium

A simple one-step rapid synthetic route is described for the preparation of silver nanoparticles by reduction of silver nitrate (AgNO3) using aqueous dextran solution which acts as both reducing and capping agent. The formation of silver nanoparticles is assured by characterization with UV-vis spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The absorbance of the silver nanoparticles is observed at 423 nm. The AFM image clearly shows the surface morphology of the well-dispersed silver nanoparticles with size range of 10-60 nm. TEM images show that the nanoparticles are spherical in shape with ∼5-10 nm dimensions. The crystallinity of Ag nanoparticles is assured by XRD analysis. The antimicrobial activity of as synthesized silver nanoparticles is tested against the bacteria, Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth is inhibited by gradual reduction of the concentration of the silver nanoparticles.

Multiple delivery cesium oven system for negative ion sources

Distribution of cesium in large negative ion beam sources to be operational in ITER, is presently based on the use of three or more cesium ovens, which operate simultaneously and are controlled remotely. However, use of multiple Cs ovens simultaneously is likely to pose difficulties in operation and maintenance of the ovens. An alternate method of Cs delivery, based on a single oven distribution system is proposed as one which could reduce the need of simultaneous operation of many ovens. A proof of principle experiment verifying the concept of a multinozzle distributor based Cs oven has been carried out at Institute for Plasma Research. It is also observed that the Cs flux is not controlled by Cs reservoir temperature after few hours of operation but by the temperature of the distributor which starts behaving as a Cs reservoir.

Optimization of negative ion current in a compact microwave driven upper hybrid resonance multicusp plasma source

Performance of a microwave driven upper hybrid resonance multicusp plasma source as a volume negative ion source is reported. Microwaves are directly launched into the plasma chamber predominantly in the TE(11) mode. The source is operated at different discharge conditions to obtain the optimized negative H(-) ion current which is ∼33 μA (0.26 mA∕cm(2)). Particle balance equations are solved to estimate the negative ion density, which is compared with the experimental results. Future prospects of the source are discussed.

Preliminary studies on local anesthetic and antipyretic activities of Spilanthes acmella Murr. in experimental animal models

OBJECTIVE

Spilanthes acmella Murr. (Family: Compositae) is a herb that grows throughout the tropics. It is used in the treatment of rheumatism, fever, sore throat, and hemorrhoids. A tincture of the flowers is used to relieve toothache. The leaves and flowers produce numbness of the tongue when eaten as salad. The present study was undertaken to evaluate the local anesthetic and antipyretic activities of S. acmella in experimental animal models.

MATERIALS AND METHODS

Aqueous extract of S. acmella Murr. (SAM) was tested for local anesthetic action by (i) intracutaneous wheal in guinea pigs and (ii) plexus anesthesia in frogs. In both the models, 2% xylocaine was used as the standard drug. The anti-pyretic activity was determined by yeast-induced pyrexia in rats. Aspirin 300 mg/kg was used as the standard drug.

RESULT

The test drug in concentrations of 10% and 20% produced 70.36% and 87.02% anesthesia respectively by the intracutaneous wheal compared to 97.22% anesthetic effect produced by 2% xylocaine (P<0.001). The mean onset of anesthesia with the test drug was 5.33±0.57 min compared to 2.75±0.31 min (P<0.001) for the standard drug in the plexus anesthesia model. In the anti-pyretic model, ASA in doses of 100, 200, and 400 mg produced dose-dependent reduction in mean temperature at various hours of observation.

CONCLUSION

The present study shows that SAM has significant local anesthetic and antipyretic activities.

Coccidioidomycosis in India: Report of a third imported case

We describe the third fatal case of imported coccidioidomycosis in India in a 31-year-old mechanical engineer originally from Andhra Pradesh, India, who lived in Gwinner, North Dakota. He had traveled to Arizona in summer of 2006, where he drove tractors in a dusty environment at a tractor production facility near Phoenix, Arizona. He was human immunodeficiency virus (HIV) positive. Initially, he was treated in Fargo, North Dakota, in 2006, with liposomal amphotericin B followed by oral fluconazole. Antiretroviral treatment for HIV infection was started. He moved back to India and was admitted to the intensive care unit of St. John's Medical College and Hospital, Bangalore, India. His blood cultures yielded Coccidioides sp. The identity of the isolate was confirmed using the Gen Probe Accuprobe test at the Centers for Disease Control and Prevention, Atlanta, Georgia. In spite of initiation of treatment with antifungal agents (amphotericin B and fluconazole), his condition deteriorated and he expired three days following his admission to the hospital.

Quantification of hypoxia-inducible factor-1α, vascular endothelial growth factor, and angiopoietin-2 expression in hepatocellular carcinoma using a real-time quantitative reverse transcription polymerase chain reaction

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Background: Hepatocellular carcinoma (HCC) is characteristically a hypervascular tumor and its progression is closely related to angiogenesis. Hypoxia inducible factor-1α (HIF-1 α), vascular endothelial growth factor (VEGF), and angiopioetin-2 (Ang-2) are key angiogenic factors in HCC. In this study, expression of HIF-1α, VEGF, and Ang-2 were analyzed and correlated with clinicopathologic features of HCC.

Methods: Expression of HIF-1α, VEGF, and Ang-2 were analyzed by real-time quantitative reverse transcription polymerase chain reaction in 67 HCC patients (23HBV, 22HCV, 22NBNC) with mean age 59.09 ± 11.13 years (60 M: 7 F), 9 cirrhosis patients (2HBV, 2HCV, 5ALD) with mean age 48.33 ± 11.31 years (8 M:1 F), and 14 chronic hepatitis patients (7HBV, 7HCV) with mean age 48.33 ± 7.17 years (10 M: 4 F), respectively. HCC was diagnosed on the basis of EASL (European Association for the Study of the Liver) criteria.

Results: Expression of HIF-1α and VEGF were found to be significantly higher in patients with HCC compared with cirrhosis and chronic hepatitis. Although Ang-2 expression was higher in HCC compared to cirrhosis and chronic hepatitis but the difference was not statistically significant. The difference in the expression of HIF-1α, VEGF, and Ang-2 in cirrhosis and chronic hepatitis were not significant. Tumor size was positively correlated with HIF-1 α(p = 0.268, p = 0.030)and VEGF (p = 0.546, p = 0.0001). A positive correlation was also seen between the HIF-1α and VEGF expression (p = 0.347, p = 0.0001). However no correlation of HIF-1α, VEGF and Ang-2 was seen with portal vein thrombosis, cirrhosis, etiology, AST, ALT, and platelets.

Conclusions: HIF-1α and VEGF were highly expressed in HCC patients and may be responsible for the HCC growth. Further studies with a larger number of patients need to be done.

No significant financial relationships to disclose.

Isolated syncope - an uncommon presenting feature of pulmonary embolism

We describe a case of a 62 year old man who presented with transient loss of consciousness following exertion. On presentation to hospital, he was haemodynamically stable and was not breathless, tachycardic or hypoxic at rest. The finding of exercise-induced desaturation on pulse oximetry triggered further investigations which confirmed the presence of PE.

The effect of surface stress on the propagation of Lamb waves

This work investigates the possibility of the propagation of Lamb waves in thin solid layers with external traction free surfaces, in the presence of surface elasticity, inertia and residual stress. It is demonstrated that such waves do exist and that their characteristics can be quite different from their classical counterparts. The governing equations with non-classical boundary conditions involving the bulk and surface stress are solved exactly in the frequency-wavenumber domain. This solution is utilized to compute the Lamb wave modes for different layer thicknesses. An efficient strategy to capture all the modes of Lamb waves within a given frequency window is outlined. It is shown that the effect of surface elasticity and inertia becomes significant with increasing frequency and decreasing layer thickness, where the number of modes participating within a given frequency window is more than that permitted by the classical theory. Further, it is observed that the nature of the Lamb wave modes (in terms of negative dispersion) in the presence of surface stress is similar to what predicted by the nonlocal theory and microstructure based continuum theory.

Clostridial myonecrosis clinically resembling black quarter in an Indian elephant (Elephas maximus)

An Indian elephant (Elephas maximus) which died of acute fatal myonecrosis was examined to determine the aetiology of the infection. The causative organism was identified as Clostridium perfringens type A. Out of five genes encoding for major toxins (cpa, cpb, etx, iA, and cpe genes) the isolate was found to harbour the cpa gene only, as tested by multiplex polymerase chain reaction. It flanks a 324 base pair segment in the cpa gene, indicating the presence of the alpha toxin gene. The organism was sensitive to amikacin, ampicillin, enrofloxacin, gentamicin and norfloxacin but was resistant to bacitracin, oxytetracycline and tetracycline. The acute malignant nature of the myonecrosis and presence of the alpha toxin gene in the isolate suggested that the myonecrosis, although clinically resembling that caused by C. chauvoei in cases of black quarter, was caused by C. perfringens type A.

Finding vessels--accuracy of CT for identifying anomalous feeding vessels in patients with congenital cystic lung lesions

INTRODUCTION

Contrast computer tomography (CT) scanning is the investigation of choice for the further assessment of suspected cystic congenital lung lesions (CCLL). Its use to identify the presence of anomalous feeding vessels supplying the lesion is well documented, but data regarding its accuracy is limited. This study compares CT results to operative and pathological findings to determine the accuracy of CT in identifying these anomalous vessels.

METHODS

51 consecutive cases of cystic congenital lung lesions managed in one hospital by a single consultant were reviewed. All cases had contrast CT scans performed preoperatively, as standard practice in this institution. We compared the results of these CT scans to the macroscopic appearance at surgery and histological findings postoperatively. We also compared the results of 2 CT protocols used in our institution between 1999-2007 and 2007-2009, respectively.

RESULTS

Anomalous vessels were reported on CT in 9 cases. All but 1 had concordant operative and pathological findings. In the remaining 42 cases, no anomalous vessels were seen on CT. Of these, 9 cases were found to have an anomalous blood supply at surgery, 6 of which were hybrid lesions and 3 isolated sequestrations. The specificity of CT in identifying feeding vessels in the study was 97% (95% CI: 0.83-0.99) and the sensitivity was 47% (95% CI: 0.23-0.71). The positive predictive value was 89% (95% CI: 0.50-0.99) and negative predictive value 79% (95% CI: 0.62-0.89). The most recent protocol yielded an improved sensitivity of 75% (95% CI: 0.22-0.98) and a specificity of 100% (95% CI: 0.46-1.0) with a 100% (95% CI: 0.31-1.0) positive and 83% (95% CI: 0.36-0.99) negative predictive value.

CONCLUSION

CT is a specific investigation for identifying anomalous vessels in CCLL but lacks sensitivity, leading to a relatively low negative predictive value. This emphasises the need in every case to look for anomalous vessels at surgery to avoid morbidity and potential mortality. An improved protocol for CT scans leads to improved specificity and sensitivity and predictive values.

Radiation induced effects on viability and antioxidant enzymes of crustaceans from different habitats

The paper describes differential tolerance of two fresh water crustaceans Mesocyclops hyalinus and Allodiaptomus satanus to 60Co gamma radiation. Mesocyclops hyalinus is dominant species at site 1, near a Thermal Power Plant at Kolaghat East Midnapore where fly ash deposition is a regular phenomenon. Allodiaptomus satanus is dominant species at site 2 at Kolkata, Ballygung where anthroponotic activities are more pronounced. M. hyalinus is naturally exposed to more stressful situation than A. satanus as revealed by comparing the hydrological parameters of the two habitats. Experimental exposure to ionizing radiation resulted in differential changes in viability morphology and antioxidant enzyme activities in the two selected species. Survival experiments showed greater tolerance of M. hyalinus compared to A. satanus up to 8Gy (absorbed dose) after which if showed drastic fail in survival. More pronounced morphological changes were observed in A. satanus as compared to that in M. hyalinus. The pattern of changes in antioxidant enzyme activity is distinctly opposite in the two radiation exposed species. While in M. hyalinus stimulation in activity of both CAT (excepting at 10Gy absorbed dose) and SOD was observed A. satanus showed decrease in activity of both the enzymes when compared to their unirradiated counterparts.

Predictors of survival in patients with non-curative stage IV cancer and malignant bowel obstruction

PURPOSE

Malignant bowel obstruction (MBO) occurs in up to 15% of patients admitted to palliative care wards and management can be clinically challenging. Survival is generally poor with a reported median survival of 1-3 months; however, there are no studies describing predictors of survival for patients with MBO.

PATIENTS AND METHODS

All patients admitted to a tertiary care hospital with a MBO were approached between March 1, 2006 and March 31, 2008 to enter the study. Demographic, clinical, laboratory, and radiographic information were prospectively collected from patient charts and the patient's functional status (Eastern Cooperative Oncology Group score, ECOG) at admission was recorded. Follow-up was until death or the end of the study (August 2008). Survival was estimated using Kaplan-Meier plots and Cox regression models were used to evaluate prognostic factors for survival.

RESULTS

Thirty-five patients were recruited. Median patient age was 61% and 46% were female. Median survival of the cohort was 80 days (range 7-873). Median survival for patients with an ECOG performance status of 0-1 (n = 15) was 222 days, for ECOG 2 patients (n = 9), 63 days and for patients with an ECOG 3/4 score (n = 11) it was 27 days. ECOG status was the strongest predictor of survival on the multivariate analysis. In addition, a low blood urea nitrogen level or a high albumin on admission was also associated with prolonged survival.

CONCLUSION

An ECOG score of 0/1 for patients with MBO in the setting of Stage IV non-curative cancer is the strongest predictor of overall survival.

Room for improvement? A quality-of-life assessment in patients with malignant bowel obstruction

This prospective study followed 35 patients admitted to hospital with malignant bowel obstruction (MBO) to evaluate quality of life (QOL). Subjects completed the Edmonton Symptom Assessment Scale (ESAS) and Rotterdam Symptom Checklist (RSCL) at recruitment, and at one week, one month and three months.The highest ranked ESAS scores at recruitment (which was generally 18-36 hours post admission to hospital) included loss of appetite (median=7.5), fatigue (6.5) and overall well-being (6.0). The total ESAS score improved by 7.5, 11.5 and 11.0 points respectively at one week, one month and three months (p<0.05, p<0.01, NS).RSCL median scores for physical and psychological subscales were high at baseline (36.2, 42.9) and improved significantly at one week and one month (p<0.05). Psychological functioning appeared to be worsening by three months and at no time did activity level improve significantly. The overall QOL score was extremely poor at baseline (6.0 median) improving to 3.3 at one month (median fall=1.0, p<0.05) and 3.4 at three months.Further work should address the lack of improvement in activity and apparent deterioration in psychological functioning after one month.

Epidemiology of group A streptococcal pharyngitis & impetigo: a cross-sectional & follow up study in a rural community of northern India

BACKGROUND & OBJECTIVE

Group A streptococcus (GAS) causes a wide array of human diseases. Epidemiological picture of streptococcal infection in India is not complete. Hence, disease burden due to GAS in 5-15 yr old school children in northern India was studied and emm typing of GAS isolates was carried out to help in designing prevention strategies.

METHODS

A cross-sectional survey was carried out among 4249 school children (5-15 yr) from Raipur Rani Block of Panchkula district in Haryana during 2000-2002; 334 children were followed up fortnightly for one year. Standard clinical and microbiological procedures were used for collection of swabs from throat and skin and confirmation of GAS and its emm types.

RESULTS

Of the 4249 children studied, 658 (15.5%) had pharyngitis; 579 of them could be swabbed, of which 2.8 per cent had GAS. From 3591 children without pharyngitis, 3385 who could be swabbed, GAS was found in 1.3 per cent of them. Impetigo was rare (0.7%), but 7.1 per cent (2/28) children had GAS. In the followup study, 17.4 per cent (776/4447 child-contacts) had pharyngitis, 761 could be swabbed and 2.4 per cent had GAS; among those without pharyngitis, 2016 swabs could be taken and GAS was found in 1.3 per cent; whereas only 2.6 per cent (2/75) of skin sores had GAS. Three children had GAS pharyngitis twice during follow up. Fourteen different GAS emm types were found. emm 71, 77 and 81 constituted 69 per cent of the pharyngeal isolates. GAS pharyngitis and impetigo were more common in winters and summers respectively.

INTERPRETATION & CONCLUSION

In north India, pharyngitis was more common than impetigo. Most prevalent emm types of GAS in this region differ from those included in M protein-based vaccines.