Molecular detection of Orientia tsutsugamushi in ectoparasites & their small mammal hosts captured from scrub typhus endemic areas in Madurai district, India.

BACKGROUND OBJECTIVES: Scrub typhus, caused by Orientia tsutsugamushi present in small mammals harbouring the ectoparasites. A study was undertaken to detect the pathogen present in small mammals and its ectoparasites in the scrub typhus-reported areas. METHODS: The small mammals (rodents/shrews) and its ectoparasites were screened for O. tsutsugamushi using nested PCR amplification of the groEL gene. Small mammals were collected by trapping and screened for ectoparasites (mites, ticks and fleas) by combing method. RESULTS: All the chigger mites collected were tested negative for O. tsutsugamushi . Interestingly, adult non-trombiculid mites ( Oribatida sp., Dermanyssus gallinae ), fleas ( Xenopsylla astia, X. cheopis, Ctenophalides felis and Ctenophalides sp.) and ticks ( Rhipicephalus sanguineus , R. haemaphysaloides ) screened were found to be positive for O. tsutsugamushi , which the authors believe is the first report on these species globally. Bandicota bengalensis with O. tsutsugamushi infection is reported for the first time in India. The O. tsutsugamushi groEL sequences from the positive samples were similar to the reference strains, Karp and Ikeda and phylogenetically clustered in clade IV with less evolutionary divergence. The blood samples of Rattus rattus , Suncus murinus and B. bengalensis collected from this area were tested positive for O. tsutsugamushi ; interestingly, the sequence similarity was much pronounced with their ectoparasites indicating the transmission of the pathogen to host or vice versa . INTERPRETATION CONCLUSIONS: The outcome of the present investigations widened our scope on the pathogens present in ectoparasites and rodents/shrews from this area. This will help to formulate the required vector control methods to combat zoonotic diseases.

Outcomes of peroral endoscopic myotomy in patients with achalasia and prior bariatric surgery: A multicenter experience.

Peroral endoscopic myotomy (POEM) in patients with achalasia who are status post bariatric surgery may be technically challenging due to postsurgical scarring and altered anatomy. The aim of the study was to assess the efficacy and safety of POEM for achalasia in patients with prior bariatric surgery. A review of prospectively maintained databases at three tertiary referral centers from January 2015 to January 2021 was performed. The primary outcome of interest was clinical success, defined as a post-treatment Eckardt score ≤ 3 or improvement in Eckardt score by ≥ 1 when the baseline score was <3, and improvement of symptoms. Secondary outcomes were adverse event rates and symptom recurrence. Sixteen patients status post Roux-en-Y gastric bypass (n = 14) and sleeve gastrectomy (n = 2) met inclusion criteria. Indications for POEM were achalasia type I (n = 2), type II (n = 9), and type III (n = 5). POEM was performed either by anterior or posterior approach. The pre-POEM mean integrated relaxation pressure was 26.2 ± 7.6 mm Hg. The mean total myotomy length was 10.2 ± 2.7 cm. The mean length of hospitalization was 1.4 ± 0.7 days. Pre- and postprocedure Eckardt scores were 6.1 ± 2.1 and 1.7 ± 1.8, respectively. The overall clinical success rate was 93.8% (15/16) with mean follow-up duration of 15.5 months. One patient had esophageal leak on postprocedure esophagram and managed endoscopically. Dysphagia recurred in two patients, which was successfully managed with pneumatic dilation with or without botulinum toxin injection. POEM appears to be safe and effective in the management of patients with achalasia who have undergone prior bariatric surgery.

Dengue infection among tribal population in the Nilgiris district, Tamil Nadu, India.

BACKGROUND & OBJECTIVES: Dengue emerged as an important public health problem in Tamil Nadu from 2000 onwards, reported in all the districts as an endemic disease of Tamil Nadu except Nilgiris district. So this study was carried out to understand the dengue epidemiology in Nilgiris district. METHODS: Block-wise study was made at the Nilgiris district. The clinicians at the Nilgiris Adivasi Welfare Association hospitals (NAWA) situated in Kotagiri, Kozhikarai and Primary Health Centers from Kunjpannai, Arayoor, and Soloor Mattam, examined and recorded symptoms and collected blood samples from the dengue-suspected patients. These samples were centrifuged at 4°C and stored. Serum samples (267 nos.) collected from dengue-suspected patients for two years period from 2014 to 2016 were screened for dengue infection. RESULTS: First year study conducted during 2014-15 showed 13 dengue positives (8.39%) mainly from Kotagiri block (9 nos. - 69.2%) and the second year study conducted during 2015-16 showed 12 dengue positives (10.71%) found mostly from Udagamandalam block (6 nos.- 50%). People belonging to 6 different tribes - Irular, Toda, Kota, Kurumba, Kattunaickan, and Paniya were found infected with dengue and more Irular positives were recorded in both the years (5 Irular-2014-15 & 11 Irular -2015-16). First year detected more female positives (92.3%) whereas the second year showed 5 males (41.7%) and 7 females (58.3%). INTERPRETATION & CONCLUSION: This study unearthed the hidden disease dengue to be prevalent among the tribal community and emphasized the need for the establishment of a permanent dengue surveillance system with improved disease diagnostics, to initiate effective vector control efforts to stop dengue transmission from this hilly region.

Liquid Nitrogen Spray Cryotherapy in Treatment of Barrett's Esophagus, where do we stand? A Systematic Review and Meta-Analysis.

Radiofrequency ablation (RFA) is the preferred treatment option for Barrett's esophagus (BE) to achieve complete eradication (CE) of dysplasia (D), and intestinal metaplasia (IM). Cryotherapy, using liquid nitrogen (LNC), is a cold-induced tissue-injury technique option for the ablation of BE. We conducted a systematic review and meta-analysis to assess the overall efficacy and safety of LNC in the treatment of BE. We conducted a search of multiple electronic databases and conference proceedings from inception through June 2018. The primary outcome was to estimate the pooled rates of CE-IM, CE-D, and CE-HGD. The secondary outcome was to estimate the risk of adverse events and recurrence of disease after LNC. Nine studies reported 386 patients who were treated with LNC. The pooled rate of CE-IM was 56.5% (95% CI 48.5-64.2, I2 = 47), pooled rate of CE-D was 83.5% (95% CI 78.3-87.7, I2 = 22.8), and pooled rate of CE-HGD was 86.5% (95% CI 64.4-95.8, I2 = 88.1). Rate of adverse events was 4.7%, and the risk of BE recurrence was 12.7%. On subgroup analysis, the pooled rate of CE-IM with LNC in patients who failed RFA was 58.4% (95% CI 47.2-68.8, I2 = 32.5), and the pooled rate of CE-D in the same population was 81.9% (95% CI 72.5-88.6, I2 = 5.9). CE-D rates with LNC are comparable to RFA while CE-IM rates appear to be lower than the rates achievable with RFA. CE-IM rate in RFA failed patients is 58.4% and thus LNC is a rescue option to consider in this population.

Prognostic implications of recipient or donor hepatitis B seropositivity in thoracic transplantation: analysis of 426 hepatitis B surface antigen-positive recipients.

BACKGROUND: Prognostic data on survival of hepatitis B surface antigen-positive (HBsAg+) recipients and of hepatitis B core antibody-positive (HBcAb+) donors are limited in the thoracic transplantation (TT) cohort. Improved understanding of risks could potentially expand the recipient and donor pools. METHODS: Post-hoc analysis of limited-access dataset of the United Network for Organ Sharing database from January 2000-September 2010 was performed. Analyses were performed for all TT, including single and bilateral lung, orthotopic heart, and simultaneous heart-lung transplants. The primary analyzed outcome was overall survival. A Cox proportional multivariate hazards model was used to adjust for significant risk predictors. RESULTS: Of 24,817 patients included, 426 recipients were HBsAg+, of whom 106 (25%) died during a mean follow-up of 3.6 years. On multivariate analysis, recipient HBsAg+ (hazard ratio [HR] = 0.88, 95% confidence interval [CI]: 0.69-1.32; P = 0.80), and donor HBcAb+ (HR = 0.91, 95% CI: 0.68-1.22; P = 0.53) were not associated with increased overall mortality in the entire TT cohort, with similar results for each individual transplant cohort. Unadjusted survival analysis using Kaplan-Meier curves in individual transplant cohorts did not show significant differences between HBsAg+ and HBsAg- recipients. No statistically significant differences were found between causes of mortality in the 2 groups. CONCLUSION: HBsAg+ status of recipients or HBcAb+ status of donors does not significantly affect overall survival of TT recipients. These data add to the scant literature on this subject and could potentially increase the donor and recipient pools.

Liver transplantation of hepatitis B surface antigen positive donors to hepatitis B core antibody recipients: analysis of 27 patients.

AIM: Shortage of donor livers is the major limiting factor for liver transplantation (LT). While livers from patients with past infection of Hepatitis-B (HBcAb+) are commonly used as donors, scant data exists on outcomes following transplantation of HBsAg+ donor livers. The impact of donor HBsAg positivity on recipient survival is currently analyzed. METHODS: Post hoc analysis of all adults undergoing LT from October 1987-September 2010 registered in United Network for Organ Sharing/Organ Procurement and Transplantation Network, a concurrent, limited access database of all American LT recipients. Only recipients who were HBcAb+ were analyzed. LTs with missing donor or recipient serologic parameters for Hepatitis-B were excluded. Significant predictors of survival were determined by univariate analysis. Cox proportional hazards model was used to determine independent risk predictors in the multivariate analysis. RESULTS: The population consisted of 13,329 LT recipients. The mean age of donors and recipients were 40±16 years and 52±9 years respectively. The mean follow-up was 3.7 years. Study population included 27 recipients transplanted with HBsAg+ grafts, of whom 7 (28%) died. Outcomes were adjusted for donor age, recipient age, donor gender, recipient gender, type of LT, MELD score, HCV status, previous LT, and cold ischemic time. On multivariate analysis, LT recipient outcomes were not significantly different for HBsAg+ donors versus donors without prior hepatitis B infection (HR: 1.14, 95% CI: 0.93-1.39, P=0.17). Kaplan-Meier curves revealed no significant survival difference between the two groups. CONCLUSION: These results suggest that donor HBsAg positivity did not affect overall survival of LT recipients. These findings could potentially expand the pool of liver donors.

Entomo-epidemiological investigations on chikungunya outbreak in the Lakshadweep islands, Indian Ocean.

BACKGROUND & OBJECTIVE: An outbreak of chikungunya fever characterized by prolonged incapacitation in the Lakshadweep islands in Indian Ocean occurred in November 2006. We undertook the entomological and epidemiological investigations on the Chikungunya outbreak in the Lakshadweep islands, Indian Ocean. METHODS: Epidemic information in the affected places was obtained from the local hospital records. Entomological observations like larval survey and the adult resting/landing collections by the hand collection methods were individually conducted in the two affected islands Andrott and Kalpeni in November and December 2006. RESULTS: The main breeding sources of the mosquitoes were the rodent-devoured coconuts, coconut shells, areca nut soaking mud and plastic pots, discarded containers, grinding stones, metal containers and plastic containers. Aedes albopictus was pre-dominantly present in the Lakshadweep islands. INTERPRETATION & CONCLUSION: It is concluded that the routine campaigns need to be organized regularly within the community highlighting the potential breeding grounds of mosquitoes and the possible control methods. Source reduction strategies like destruction of coconut shells and rodent-devoured coconuts by burning or by burying them inside the ground. Ae. albopictus played major role as the vector mosquitoes responsible for the chikungunya transmission.

Trade off between variable and fixed size normalization in orthogonal polynomials based iris recognition system.

Iris normalization is an important stage in any iris biometric, as it has a propensity to trim down the consequences of iris distortion. To indemnify the variation in size of the iris owing to the action of stretching or enlarging the pupil in iris acquisition process and camera to eyeball distance, two normalization schemes has been proposed in this work. In the first method, the iris region of interest is normalized by converting the iris into the variable size rectangular model in order to avoid the under samples near the limbus border. In the second method, the iris region of interest is normalized by converting the iris region into a fixed size rectangular model in order to avoid the dimensional discrepancies between the eye images. The performance of the proposed normalization methods is evaluated with orthogonal polynomials based iris recognition in terms of FAR, FRR, GAR, CRR and EER.

Systematic review with meta-analysis: prevalent vs. incident oesophageal adenocarcinoma and high-grade dysplasia in Barrett's oesophagus.

BACKGROUND: The proportion of oesophageal adenocarcinoma that is detected concurrently with initial Barrett's oesophagus diagnosis is not well studied. AIM: To compare the proportion of prevalent adenocarcinoma vs. incident adenocarcinoma found during surveillance of Barrett's. METHODS: We performed a systematic search of MEDLINE, EMBASE and Web of Science (from their inception to 31 May 2015) for cohort studies in adults with Barrett's (nondysplastic Barrett's ± Barrett's with low-grade dysplasia) with minimum average follow-up of 3 years, and providing numbers of prevalent adenocarcinoma detected (concurrently with Barrett's diagnosis and up to 1 year afterwards) vs. incident adenocarcinoma detected (greater than 1 year after Barrett's diagnosis). Pooled weighted proportions of prevalent and incident adenocarcinoma were calculated, using a random effects model. RESULTS: On meta-analysis of 13 studies reporting on 603 adenocarcinomas in 9657 Barrett's patients, 85.1% of adenocarcinomas were classified as prevalent [95% confidence interval (CI), 78.1-90.2%) and 14.9% as incident (95% CI, 9.8-21.9%), with substantial heterogeneity (I(2) = 66%). Among nine studies reporting on 787 high-grade dysplasia and oesophageal adenocarcinomas in 8098 Barrett's patients, the proportion of prevalent high-grade dysplasia-oesophageal adenocarcinoma was similar at 80.5% (95% CI, 68.1-88.8%, I(2) = 87%). These results remained stable across multiple subgroup analyses including study quality, setting, duration of follow-up and presence of baseline dysplasia. CONCLUSIONS: In our meta-analysis, four of five patients diagnosed with adenocarcinoma or high-grade dysplasia at index endoscopy or within 1 year of Barrett's follow-up were considered to be prevalent cases. Continued efforts are needed to identify patients with Barrett's before the development of adenocarcinoma.

Solvent isotope effects on NMR spectral parameters in high-spin ferric hemoproteins: an indirect probe for distal hydrogen bonding.

The influence of solvent isotope composition on 1H-NMR resonance position and linewidth of heme methyls has been investigated for a variety of high-spin ferric hemoproteins for the purpose of detecting hydrogen-bonding interactions in the heme cavity. Consistently larger hyperfine shifts and paramagnetic linewidths in 2H2O than 1H2O are observed for metmyoglobins and methemoglobin possessing a coordinated water molecule. The analysis of the dynamics of labile proton exchange in sperm whale metmyoglobin, and the absence of any isotope effects in the five-coordinate Aplysia metmyoglobin, indicate that the significant axial modulation of heme electronic structure by solvent isotope is consistent with arising from distal hydrogen-bonding interactions. The presence or absence of similarly large isotope effects on shifts and linewidths in other hemoproteins, depending on the presence of a bound water in the distal heme pocket, suggests that this isotope effect can serve as a probe for the presence of such bound water. The absence of any detectable isotope effect on either shifts or linewidths in resting-state horseradish peroxidase supports a five-coordinate structure with bound water absent from the vicinity of the iron.

NMR studies of internal dynamics of serine proteinase protein inhibitors: Binding region mobilities of intact and reactive-site hydrolyzed Cucurbita maxima trypsin inhibitor (CMTI)-III of the squash family and comparison with those of counterparts of CMTI-V of the potato I family.

Serine proteinase protein inhibitors follow the standard mechanism of inhibition (Laskowski M Jr, Kato I, 1980, Annu Rev Biochem 49:593-626), whereby an enzyme-catalyzed equilibrium between intact (I) and reactive-site hydrolyzed inhibitor (I*) is reached. The hydrolysis constant, Khyd, is defined as [I*]/[I]. Here, we explore the role of internal dynamics in the resynthesis of the scissile bond by comparing the internal mobility data of intact and cleaved inhibitors belonging to two different families. The inhibitors studied are recombinant Cucurbita maxima trypsin inhibitor III (rCMTI-III; Mr 3 kDa) of the squash family and rCMTI-V (Mr approximately 7 kDa) of the potato I family. These two inhibitors have different binding loop-scaffold interactions and different Khyd values--2.4 (CMTI-III) and 9 (CMTI-V)--at 25 degrees C. The reactive-site peptide bond (P1-P1') is that between Arg5 and Ile6 in CMTI-III, and that between Lys44 and Asp45 in CMTI-V. The order parameters (S2) of backbone NHs of uniformly 15N-labeled rCMTI-III and rCMTI-III* were determined from measurements of 15N spin-lattice and spin-spin relaxation rates, and [1H]-15N steady-state heteronuclear Overhauser effects, using the model-free formalism, and compared with the data reported previously for rCMTI-V and rCMTI-V*. The backbones of rCMTI-III [(S2) = 0.71] and rCMTI-III* [(S2) = 0.63] are more flexible than those of rCMTI-V [(S2) = 0.83] and rCMTI-V* [(S2) = 0.85]. The binding loop residues, P4-P1, in the two proteins show the following average order parameters: 0.57 (rCMTI-III) and 0.44 (rCMTI-III*); 0.70 (rCMTI-V) and 0.40 (rCMTI-V*). The P1'-P4' residues, on the other hand, are associated with (S2) values of 0.56 (rCMTI-III) and 0.47 (rCMTI-III*); and 0.73 (rCMTI-V) and 0.83 (rCMTI-V*). The newly formed C-terminal (Pn residues) gains a smaller magnitude of flexibility in rCMTI-III* due to the Cys3-Cys20 crosslink. In contrast, the newly formed N-terminal (Pn' residues) becomes more flexible only in rCMTI-III*, most likely due to lack of an interaction between the P1' residue and the scaffold in rCMTI-III. Thus, diminished flexibility gain of the Pn residues and, surprisingly, increased flexibility of the Pn' residues seem to facilitate the resynthesis of the P1-P1' bond, leading to a lower Khyd value.

Disulfide bond effects on protein stability: designed variants of Cucurbita maxima trypsin inhibitor-V.

Attempts to increase protein stability by insertion of novel disulfide bonds have not always been successful. According to the two current models, cross-links enhance stability mainly through denatured state effects. We have investigated the effects of removal and addition of disulfide cross-links, protein flexibility in the vicinity of a cross-link, and disulfide loop size on the stability of Cucurbita maxima trypsin inhibitor-V (CMTI-V; 7 kD) by differential scanning calorimetry. CMTI-V offers the advantage of a large, flexible, and solvent-exposed loop not involved in extensive intra-molecular interactions. We have uncovered a negative correlation between retention time in hydrophobic column chromatography, a measure of protein hydrophobicity, and melting temperature (T(m)), an indicator of native state stabilization, for CMTI-V and its variants. In conjunction with the complete set of thermodynamic parameters of denaturation, this has led to the following deductions: (1) In the less stable, disulfide-removed C3S/C48S (Delta Delta G(d)(50 degrees C) = -4 kcal/mole; Delta T(m) = -22 degrees C), the native state is destabilized more than the denatured state; this also applies to the less-stable CMTI-V* (Delta Delta G(d)(50 degrees C) = -3 kcal/mole; Delta T(m) = -11 degrees C), in which the disulfide-containing loop is opened by specific hydrolysis of the Lys(44)-Asp(45) peptide bond; (2) In the less stable, disulfide-inserted E38C/W54C (Delta Delta G(d)(50 degrees C) = -1 kcal/mole; Delta T(m) = +2 degrees C), the denatured state is more stabilized than the native state; and (3) In the more stable, disulfide-engineered V42C/R52C (Delta Delta G(d)(50 degrees C) = +1 kcal/mole; Delta T(m) = +17 degrees C), the native state is more stabilized than the denatured state. These results show that a cross-link stabilizes both native and denatured states, and differential stabilization of the two states causes either loss or gain in protein stability. Removal of hydrogen bonds in the same flexible region of CMTI-V resulted in less destabilization despite larger changes in the enthalpy and entropy of denaturation. The effect of a cross-link on the denatured state of CMTI-V was estimated directly by means of a four-state thermodynamic cycle consisting of native and denatured states of CMTI-V and CMTI-V*. Overall, the results show that an enthalpy-entropy compensation accompanies disulfide bond effects and protein stabilization is profoundly modulated by altered hydrophobicity of both native and denatured states, altered flexibility near the cross-link, and residual structure in the denatured state.

Natural abundance 15N NMR assignments delineate structural differences between intact and reactive-site hydrolyzed Cucurbita maxima trypsin inhibitor III.

15N NMR assignments were made to the backbone amide nitrogen atoms at natural isotopic abundance of intact and reactive-site (Arg5-Ile6) hydrolyzed Cucurbita maxima trypsin inhibitor III (CMTI-III and CMTI-III*, respectively) by means of 2D proton-detected heteronuclear single bond chemical shift correlation (HSBC) spectroscopy, utilizing the previously made sequence-specific 1H NMR assignments (Krishnamoorthi et al. (1992) Biochemistry 31, 898-904). Comparison of the 15N chemical shifts of the two forms of the inhibitor molecule revealed significant changes not only for residues located near the reactive-site region, but also for those distantly located. Residues Cys3, Arg5, Leu7, Met8, Cys10, Cys16, Glu19, His25, Tyr27, Cys28 and Gly29 showed significant chemical shift changes ranging from 0.3 to 6.1 ppm, thus indicating structural perturbations that were transmitted throughout the molecule. These findings confirm the earlier conclusions based on 1H NMR investigations.

A new protein inhibitor of trypsin and activated Hageman factor from pumpkin (Cucurbita maxima) seeds.

A protein inhibitor (CMTI-V; Mr 7106) of trypsin and activated Hageman factor (Factor XIIa), a serine protease involved in blood coagulation, has been isolated for the first time from pumpkin (Cucurbita maxima) seeds by means of trypsin-affinity chromatography and reverse phase high performance liquid chromatography (HPLC). The dissociation constants of the inhibitor complexes with trypsin and Factor XIIa have been determined to be 1.6 x 10(-8) and 4.1 x 10(-8) M, respectively. The primary structure of CMTI-V is reported. The protein has 68 amino acid residues and one disulfide bridge and shows a high level of sequence homology to the Potato I inhibitor family. Furthermore, its amino terminus consists of an N-acetylates Ser. The reactive site has been established to be the peptide bond between Lys44-Asp45. The modified inhibitor which has the reactive site peptide bond hydrolyzed inhibits trypsin but not the Hageman factor.

A rare cause of dysphagia in a HIV patient--esophageal pseudodiverticulosis.

Esophageal pseudodiverticulosis is a rare clinical entity with a slight male predominance (1). The condition is caused by cystic dilation of the sub mucosal glands and hence is not true diverticulosis. This is usually a benign condition, affecting the distal third of esophagus. It has been associated with reflux esophagitis, strictures and candidiasis. Patients with esophageal pseudodiverticulosis may present with progressive dysphagia, though most cases are asymptomatic. Perforation (2), bleeding (3) and mediastinitis have rarely been described. To the best of our knowledge, the occurrence of this rare disease in HIV patients has been described only once before (4). We report the second case of esophageal pseudodiverticulosis occurring in a HIV patient.

Community-based control of Aedes aegypti by adoption of eco-health methods in Chennai City, India.

BACKGROUND: Dengue is highly endemic in Chennai city, South India, in spite of continuous vector control efforts. This intervention study was aimed at establishing the efficacy as well as the favouring and limiting factors relating to a community-based environmental intervention package to control the dengue vector Aedes aegypti. METHODS: A cluster randomized controlled trial was designed to measure the outcome of a new vector control package and process analysis; different data collection tools were used to determine the performance. Ten randomly selected intervention clusters (neighbourhoods with 100 houses each) were paired with ten control clusters on the basis of ecological/entomological indices and sociological parameters collected during baseline studies. In the intervention clusters, Aedes control was carried out using a community-based environmental management approach like provision of water container covers through community actors, clean-up campaigns, and dissemination of dengue information through schoolchildren. The main outcome measure was reduction in pupal indices (pupae per person index), used as a proxy measure of adult vectors, in the intervention clusters compared to the control clusters. RESULTS: At baseline, almost half the respondents did not know that dengue is serious but preventable, or that it is transmitted by mosquitoes. The stakeholder analysis showed that dengue vector control is carried out by vertically structured programmes of national, state, and local administrative bodies through fogging and larval control with temephos, without any involvement of community-based organizations, and that vector control efforts were conducted in an isolated and irregular way. The most productive container types for Aedes pupae were cement tanks, drums, and discarded containers. All ten intervention clusters with a total of 1000 houses and 4639 inhabitants received the intervention while the ten control clusters with a total of 1000 houses and 4439 inhabitants received only the routine government services and some of the information education and communication project materials. The follow-up studies showed that there was a substantial increase in dengue understanding in the intervention group with only minor knowledge changes in the control group. Community involvement and the partnership among stakeholders (particularly women's self-help groups) worked well. After 10 months of intervention, the pupae per person index was significantly reduced to 0·004 pupae per person from 1·075 (P = 0·020) in the intervention clusters compared to control clusters. There were also significant reductions in the Stegomyia indices: the house index was reduced to 4·2%, the container index to 1·05%, and the Breteau index to 4·3 from the baseline values of 19·6, 8·91, and 30·8 in the intervention arm. CONCLUSION: A community-based approach together with other stakeholders that promoted interventions to prevent dengue vector breeding led to a substantial reduction in dengue vector density.

Studies on community knowledge and behavior following a dengue epidemic in Chennai city, Tamil Nadu, India.

In 2001, a major dengue outbreak was recorded in Chennai city, with 737 cases (90%) out of a total of 861 cases recorded from Tamil Nadu state. A KAP survey was carried out to assess the community knowledge, attitude and practice on dengue fever (DF), following the major dengue outbreak in 2001. A pre- tested, structured questionnaire was used for data collection. The multistage cluster sampling method was employed and 640 households (HHs) were surveyed. Among the total HHs surveyed, 34.5% of HHs were aware of dengue and only 3.3% of HHs knew that virus is the causative agent for DF. Majority of the HHs (86.5%) practiced water storage and only 3% of them stored water more than 5 days. No control measures were followed to avoid mosquito breeding in the water holding containers by majority of HHs (65%). Sixty percent of HHs did not know the biting behaviour of dengue vector mosquitoes. The survey results indicate that the community knowledge was very poor on dengue, its transmission, vector breeding sources, biting behavior and preventive measures. The lack of basic knowledge of the community on dengue epidemiology and vector bionomics would be also a major cause of increasing trend of dengue in this highly populated urban environment. There is an inevitable need to organize health education programmes about dengue disease to increase community knowledge and also to sensitize the community to participate in integrated vector control programme to resolve the dengue problem.

Studies on community knowledge and behavior following a dengue epidemic in Chennai city, Tamil Nadu, India

In 2001, a major dengue outbreak was recorded in Chennai city, with 737 cases (90%) out of a total of 861 cases recorded from Tamil Nadu state. A KAP survey was carried out to assess the community knowledge, attitude and practice on dengue fever (DF), following the major dengue outbreak in 2001. A pre- tested, structured questionnaire was used for data collection. The multistage cluster sampling method was employed and 640 households (HHs) were surveyed. Among the total HHs surveyed, 34.5% of HHs were aware of dengue and only 3.3% of HHs knew that virus is the causative agent for DF. Majority of the HHs (86.5%) practiced water storage and only 3% of them stored water more than 5 days. No control measures were followed to avoid mosquito breeding in the water holding containers by majority of HHs (65%). Sixty percent of HHs did not know the biting behaviour of dengue vector mosquitoes. The survey results indicate that the community knowledge was very poor on dengue, its transmission, vector breeding sources, biting behavior and preventive measures. The lack of basic knowledge of the community on dengue epidemiology and vector bionomics would be also a major cause of increasing trend of dengue in this highly populated urban environment. There is an inevitable need to organize health education programmes about dengue disease to increase community knowledge and also to sensitize the community to participate in integrated vector control programme to resolve the dengue problem.

Proton magnetic resonance study of the influence of heme 2,4 substituents on the exchange rates of labile protons in the heme pocket of myoglobin.

Four exchangeable protons with large hyperfine shifts are assigned in the heme pocket of sperm whale met-cyano myoglobin reconstituted with heme possessing acetyl groups, ethyl groups, bromines, and hydrogens at the 2,4 position, using both relaxation and chemical-shift data. The four protons arise from the ring NH's of the proximal (F8), distal (E7), and FG2 histidines, and the peptide NH of His F8. The similarity of all chemical shifts to those of the native protein as well as the invariance of the relaxation rates of the distal histidyl ring NH dictate essentially the same structure for the heme cavity of both native and reconstituted proteins. The exchange rates with bulk water of the four labile proteins in each modified protein were determined by saturation-transfer and line width methods. All four labile protons were found to have the same exchange rate as in the native protein for acetyl and ethyl 2,4 substituents; the two resolved labile protons in the derivative with 2,4 bromine were also unchanged. The reconstituted protein with hydrogens at the 2,4 position exhibited slower exchange rates for three of the four protons, indicating an increased dynamic stability of the heme pocket in the absence of bulky 2,4 substituents.

Identification of the titrating group in the heme cavity of myoglobin. Evidence for the heme-protein pi-pi interaction.

The pH dependence of the proton NMR chemical shifts of met-cyano and deoxy forms of native and reconstituted myoglobins reflects a structural transition in the heme pocket modulated by a single proton with pK 5.1-5.6. Comparison of this pH dependence of sperm whale and elephant myoglobin and that of the former protein reconstituted with esterified hemin eliminates both the distal histidine as well as the heme propionates as the titrating residue. Reconstitution of sperm whale met-cyano myoglobin with hemin modified at the 2,4-positions leads to a systematic variation in the pK for the structural transition, thus indicating the presence of a coupling between the titrating group and the heme pi system. The results are consistent with histidine FG3 (His-FG3) being the titrating group, and a donor-acceptor pi-pi interaction between its imidazole and the heme is proposed.