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OBJECTIVE: Social network-based reproductive decisions are critical. This study compares the effect of an older peer contraceptionuse on her younger peer's use, as they share the closest social network within the household, and tend to influence one another for reproductive decisions. In this study we considered peers as two sister-in-law living in the same household. METHODS: We used data from the fifth round of National Family Health Survey which was conducted between the year 2019 and 2021. We deployed multinomial multivariable logistic regression to find the association between older women contraception use on her younger peer. Also, an attempt has been made to determine contraceptive clustering within households in India and select states. RESULTS: The multinomial analysis found that all the women in the household used the similar method, but still relied only on the female sterilization as the sole method for their family planning. The multinomial multivariable method found that younger peers were 3.42 time odds more likely to use permanent method if her older peer had used it previously. Also, it was found 11% increase in any modern contraception use of younger peer if all her older peer will use any modern contraceptives in India. For all the states, the contraception clustering within household ranged from 5% to 14%, with highest in Himachal (14%). CONCLUSION: Empowering older women as peer educators in contraception workshops can foster informed discussions, dispel myths, and promote the use of modern contraceptive methods among younger peers. Integrating such initiatives into government existing policies like Mission Parivar Vikas is crucial for improving contraceptive uptake, with ASHA workers and community health volunteers playing a pivotal role in delivering targeted education within households.
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BACKGROUND: Tobacco use causes over eight million global deaths annually, with seven million directly attributed to tobacco use and 1.2 million to second hand smoke (SHS). Smoke-free environments are crucial to counter SHS. Although India banned smoking in public places in 2008, SHS exposure remains high. Studies have noted that limiting smoking in workplaces, restaurants, etc., helps to reduce overall smoking and reduce SHS exposure. Under this background, the study explores the linkages between smoke-free workplaces and living in smoke-free homes in India. METHODS: The two rounds of the GATS India (2009-10 and 2016-17) have been used for the study. The study focuses on male tobacco smokers working indoors or outdoors or both indoors and outdoors. The sample for the study was 2,969 for GATS 1 and 2,801 for GATS 2. Dependent variables include living in a smoke-free home, while the independent variables were adherence to a smoke-free office policy and socio-demographic variables. The two rounds of the GATS data were pooled for analysis. Statistical analysis involves bivariate and multivariate analysis. RESULTS: Findings reveal that 41% of respondents worked in smoke-free workplaces in GATS 2. Nationally, smoke-free homes increased from 35% in 2009-2010 to 44% in 2016-17. Individuals with smoke-free workplaces were more likely to have smoke-free homes. The Southern region consistently exhibited the highest proportion of smoke-free homes. Urban areas and higher education correlated with increased smoke-free homes. Logistic regression analysis confirmed that workplace smoke-free status is a significant predictor of smoke-free homes. In GATS 2, respondents aged 30 years and above were less likely to have smoke-free homes, while education and Southern region residence positively influenced smoke-free homes. CONCLUSIONS: The correlation between smoke-free workplaces and smoke-free homes is linked to stringent workplace no-smoking policies, potentially deterring individuals from smoking at home. Opportunities exist for the expansion and stringent implementation of the smoke-free policies among Indian working adults, leveraging the workplace as a key setting for evidence-based tobacco control. The study highlights positive trends in India's smoke-free homes, crediting workplace policies. Effective policies, education, and regional strategies can advance smoke-free homes, stressing the pivotal role of workplace policies and advocating broader implementation.
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Política para Fumadores , Contaminación por Humo de Tabaco , Lugar de Trabajo , Humanos , Masculino , India/epidemiología , Adulto , Contaminación por Humo de Tabaco/prevención & control , Persona de Mediana Edad , Ambiente en el Hogar , Adulto Joven , AdolescenteRESUMEN
BACKGROUND: Post abortion contraceptive use is an important area in provisioning of services associated with child birth planning. This study examines the factors related to the type and timing of initiation of contraception adoption among women who had undergone induced abortion. Study also tries to identify the role of personnel who provided the abortion service on decision of family planning adoption using complementary log-log model in India. METHODOLOGY: The study uses the secondary data from the fifth round of the National Family Household Survey conducted during 2019-21. For, the analysis, we have used five-year women's reproductive calendar to extract information on contraceptive use, post last induced abortion among women. We used complementary log-log regression models, to estimate relative risk ratios and its 95% Confidence intervals (CI). RESULTS: According to NFHS-5, out of all the last pregnancies (2,55,549), about three percent resulted in abortion. Most of the abortion occurred in private facilities (55%), with the help of health professionals (71%). From the women's reproductive calendar, it was found that around 40% of the women adopted modern methods of contraception, with maximum adopting spacing method (33%), and only handful adopted permanent method (7%). It was also found that the likelihood of early adoption of permanent method increased to two times when the abortion is done by health professional compared to others [95% CI (1.25-3.30)]. CONCLUSION: This emphasises a need for quality counselling related to timing and types of family planning as an essential part of the family planning program ensuring client centric approach suited to their needs and contexts that helps in alleviating any apprehensions associated with adverse effects of modern contraceptive methods.
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Aborto Inducido , Embarazo , Niño , Femenino , Humanos , Anticoncepción , Anticonceptivos , Personal de Salud , IndiaRESUMEN
Background: Wasting develops over a short period and can be reversed with short-term interventions. The prevalence of wasting typically varies from season to season-becoming higher during the monsoon (June to September) season as compared to the winter (October to January) and summer (February to May) seasons every year in a cyclical fashion. However, to the best of our knowledge, using nationally representative demographic surveys to extensively study the impact of the timing of the survey on the results and trends around wasting has not been done so far. Objectives: The goal of this study is to ascertain whether seasonality has an impact on the trend and levels of wasting between NFHS-3 (2005-2006) and NFHS-5 (2019-2021). Methods: The analysis was based on data on 51,555, 259,627, and 232,920 children under 5 years included in NFHS-3, NFHS-4, and NFHS-5 respectively. Multivariable logistic regression analysis and the predicted probabilities approach were employed to examine the effect of the months of interview on the prevalence of wasting. The analysis was conducted for 9 states of India which had data for comparable months to compute wasting levels. Results: We found that at the national level, wasting increased in India by one per cent from NFHS-3 to NFHS-4 but declined by 2% from NFHS-4 to NFHS-5. The results show that seasonality significantly influenced the prevalence of wasting. It was observed that compared to January, the odds of wasting were particularly higher in summer and monsoon seasons, especially in the month of August across all three rounds, indicating the influence of seasonality in the prevalence of wasting in the country. Discussion: The prevalence of wasting in India needs to be interpreted across seasonal changes as seasonality affects many of the variables intrinsically related to child health and nutritional status.
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Individuals who share similar socio-economic and cultural characteristics also share similar health outcomes. Consequently, they have a propensity to cluster together, which results in positive intra-class correlation coefficients (ICCs) in their socio-demographic and behavioural characteristics. In this study, using data from four rounds of the National Family Health Survey (NFHS), we estimated the ICC for selected socio-demographic and behavioural characteristics in rural and urban areas of six states namely Assam, Gujarat, Kerala, Punjab, Uttar Pradesh, and West Bengal. The socio-demographic and behavioural characteristics included religion & caste of the household head, use of contraception & prevalence of anaemia among currently married women and coverage of full immunization services among children aged 12-23 months. ICC was computed at the level ofPrimary Sampling Units (PSUs), that is, villages in rural areas and census enumeration blocks in urban areas. Our research highlights high clustering in terms of religion and caste within PSUs in India. In NFHS-4, the ICCs for religion ranged from the lowest of 0.19 in rural areas of Kerala to the highest of 0.67 in urban areas of West Bengal. For the caste of the household head, the ICCs ranged from the lowest of 0.12 in the urban areas of Punjab to the highest of 0.46 in the rural areas of Assam. In most of the states selected for the study, the values of ICC were higher for the use of family planning methods than for full immunization. The value of ICC for use of contraception was highest for rural areas of Assam (0.15) followed by rural areas of Gujarat (0.13). A higher value of ICC has considerable implications for determining an effective sample size for large-scale surveys. Our findings agree with the fact that for a given cluster size, the higher the value of ICC, the higher is the loss in precision of the estimate. Knowing and taking into account ICCs can be extremely helpful in determining an effective sample size when designing a large-scale demographic and health survey to arrive at estimates of parameters with the desired precision.
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OBJECTIVE: Sterilization is the only family planning method that involves relatively large amount compensation. So, the study attempts to examine the role of incentives received against the sterilization procedures on the reporting of sterilization regret in India. METHODS: The study used data from the fourth round of National Family Health Survey, 2015-16, which gathered the information on sterilization regret from 1,94,207 ever-married women. Multivariate logistic analysis and predicted probabilities approach was used to study the effect of compensation received on the sterilization regret in India. RESULTS: Results show that women who have received compensation were 33% less likely to report sterilization regret. It was found that 70% of women who undergone sterilization in public facility didn't incur any expenditure, rather received incentives. It is observed that women who had undergone operation in private facility spent a large amount than women who had done their operation in public facility. The regret in the private facility mainly results from high out of pocket expenditure on sterilization procedures. Around eight percent of women regretted getting sterilized in a private hospital and received some compensation amount, vis a vis the six percent who regretted undergoing sterilization in public facility and received compensation. CONCLUSION: The study calls for a need to standardize the cost of sterilization procedure in India's health facilities. A good alternative for reducing the cost could be Public-Private Partnership.
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Conflicto Familiar , Motivación , Emociones , Femenino , Humanos , India , Esterilización , Esterilización Reproductiva/métodosRESUMEN
In India, sterilisation is the most frequent method of modern contraception, and is primarily used by women. The contemporaneous assessment of sterilisation literature focuses only on trends and patterns that are limited to socioeconomic considerations, ignoring the cohort and period issues. No study has employed Age Period Cohort (APC) analysis to highlight the effect of APC on a particular outcome to yet. We have used maximum entropy method modelling to analyse the individual influence of APC on female sterilisation in India using the four rounds of the National Family Health Survey (NFHS). While the older group had higher sterilisation rates than the younger cohort, the age effects were found to have a standard inverted U-shaped curve, with women sterilising in their mid-30s as the might have completed their desire family size. The analysis found high rural-urban differentials in utilising female sterilisation, highlighting the relevance of education and empowerment in contraceptive decision-making among the educated one. Female sterilisation has become less common among Muslims in India over time, and among uneducated women, and it has shifted to later ages with each succeeding period. This was determined to be concerning in terms of India's future fertility. Since 1947, the government has implemented numerous policies to provide women with a variety of contraceptive options; however, the dominance of female sterilisation throughout all periods demonstrates that the government's efforts to provide temporary methods were futile.
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Anticoncepción , Esterilización Reproductiva , Estudios de Cohortes , Anticonceptivos , Femenino , Humanos , IndiaRESUMEN
BACKGROUND: According to the latest round of National Family Health Survey-4 (NFHS (2015-16)) maternal and child health care (MCH) services improved drastically compared to NFHS-3. Previous studies have established that the uptake of MCH services increases the likelihood of early adoption of contraceptives among women. So, our study aims to examine if the early initiation of contraceptive has proportionately improved with the recent increase in MCH services. METHODS: This study used the reproductive calendar of NFHS-4, 2015-16, to evaluate contraceptive initiation within 12 months after the last birth among 1,36,962 currently married women in India. A complementary log-log regression model was created to examine the link between the time of initiation of contraception and MCH care at the national level. RESULTS: It was found that only a quarter of women within 12 months from last birth have adopted the modern contraceptive method. Among those majority of the females adopted sterilization mostly at the time of birth. The multivariable model identified, that the period of initiation of contraceptive depends on the gender composition of children and access to MCH services. It was found that the odds of early initiation of contraceptive use was higher when a women have only son (AOR = 1.15,95% CI- 1.22, 1.18) compared to women with only daughter. Also, it was found that women who have availed MCH services were more likely to adopt contraceptives earlier. CONCLUSION: The number of women availing MCH services has increased in India, but it did not result in a proportional increase in initiation of contraception after childbirth. Facilitating family planning services alongside MCH services will be beneficial in low-resource settings. It is a golden opportunity to educate and encourage women for early adoption of contraceptive.
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Servicios de Salud del Niño , Servicios de Salud Materna , Niño , Anticoncepción/métodos , Conducta Anticonceptiva , Anticonceptivos , Servicios de Planificación Familiar , Femenino , Humanos , India , EmbarazoRESUMEN
Stunting depicts chronic deprivation and is a huge public health problem in several developing countries. Considering the sociocultural and sociodemographic factors of India, we aimed to examine the relationship between maternal autonomy and stunting among children <35 months. We have used the data from the latest round of National Family health survey conducted in 2015-16. The main exposure variable was women's autonomy which are represented in our study by the four dimensions- decision-making, physical mobility, financial autonomy, attitudes towards domestic violence, the main predictor variable was stunting among children. Chi-square analysis, univariate and multivariable binary logistic regression analysis were performed to find the association of childhood stunting and women's autonomy. The results were reported at 5% level of significance. All the autonomy variables have shown a significant association with child stunting at 5% level of significance. The unadjusted odds of stunting were found to be significant with respect to all the four dimensions of autonomy variables except physical autonomy. However, after adjusting for other explanatory factors attenuated these relationships and made them statistically insignificant except for women's economic autonomy (AOR = 0.91; 95% C.I.-(0.85, 0.98)) which was found to be significantly affecting the child's status of stunting. Our study reinforces that maternal autonomy is a significant predictor of childhood stunting. Hence, we recommend that policy makers, while designing interventions and policies, must address the socioeconomic inequalities at the community level while devising ways to improve women's empowerment. As it has far-reaching consequences on the nutrition status of the upcoming generations.
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BACKGROUND: Food Insecurity (FI) is a crucial social determinant of health, independent of other socioeconomic factors, as inadequate food resources create a threat to physical and mental health especially among older person. The present study explores the associations between FI and cognitive ability among the aged population in India. METHODS: To measure the cognitive functioning we have used two proxies, word recall and computational problem. Descriptive analysis and multivariable logistic regression was used to understand the prevalence of word recall and computational problem by food security and some selected sociodemographic parameters. All the results were reported at 95% confidence interval. RESULTS: We have used the data from the first wave of longitudinal ageing study of India (LASI), with a sample of 31,464 older persons 60 years and above. The study identified that 17 and 5% of the older population in India experiencing computational and word recall problem, respectively. It was found that respondents from food secure households were 14% less likely to have word recall problems [AOR:0.86, 95% CI:0.31-0.98], and 55% likely to have computational problems [AOR:0.45, 95% CI:0.29-0.70]. We also found poor cognitive functioning among those experiencing disability, severe ADL, and IADL. Further, factors such as age, education, marital status, working status, health related factors were the major contributors to the cognitive functioning in older adults. CONCLUSION: This study suggest that food insecurity is associated with a lower level of cognition among the elderly in India, which highlight the need of food policy and interventional strategies to address food insecurity, especially among the individuals belonging to lower wealth quintiles. Furthermore, increasing the coverage of food distribution may also help to decrease the burden of disease for the at most risk population. Also, there is a need for specific programs and policies that improve the availability of nutritious food among elderly.
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Inseguridad Alimentaria , Abastecimiento de Alimentos , Anciano , Anciano de 80 o más Años , Cognición , Estudios Transversales , Humanos , India/epidemiología , Factores SocioeconómicosRESUMEN
BACKGROUND: According to United Nations, 19% of females in the world relied only on the permanent method of family planning, with 37% in India according to NFHS-4. Limited studies tried to measure the sterilization regret, and its correlated factors. The study tried to explore the trend of sterilization regret in India from 1992 to 2015 and to elicit the determining effects of various factors on sterilization regret, especially in context to perceived quality of care in the sterilization operations and type of providers. DATA AND METHODS: The pooled data from NFHS-1, NFHS-3 and NFHS-4 was used to explore the regret by creating interaction between time and all the predictors. Predicted probabilities were calculated to show the trend of sterilization regret amounting to quality of care, type of health provider at the three time periods. RESULTS: The sterilization regret was increased from 5 % in NFHS-1 to 7 % in NFHS-4. According to NFHS-4, for those whose sterilization was performed in private health facility the regret was found to be less (OR-0.937; 95% CI- (0.882-0.996)) compared to public health facility. Also, the results show a two-fold increase in regret when women reported bad quality of care. The results from predicted probabilities provide enough evidence that the regret due to bad quality of care in sterilization operation had increased with each subsequent round of NFHS. CONCLUSION: Many socio-economic and demographic factors have influenced the regret, but the poor quality of care contributed maximum to the regret from 1992 to 2015. The health facilities have seriously strayed from improving the health and well-being of women in providing the family planning methods. In addition, to public facilities, the regret amounting to private facilities have also increased from NFHS-1 to 4. The quality of care provided in the family planning operation should be standardized in every hospital to strengthen the health systems in the country. The couple should be motivated to adopt more of spacing methods.
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The successful management of tuberculosis (TB) requires efficient diagnosis and treatment. Further, the increasing prevalence of drug-resistant TB highlights the urgent need to develop novel inhibitors against both drug-susceptible and drug-resistant forms of disease. Malate synthase (MS), an enzyme of the glyoxylate pathway, plays a vital role in mycobacterial persistence, and therefore it is considered as an attractive target for novel anti-TB drug development. Recent studies have also ascribed an adhesin function to MS and established it as a potent diagnostic biomarker. In this study, a panel of Mycobacterium tuberculosis (Mtb) MS-specific single-stranded DNA aptamers was identified by Systematic Evolution of Ligands by EXponential enrichment (SELEX). The best-performing G-quadruplex-forming 44-mer aptamer, MS10, was optimized post-SELEX to generate an 11-mer aptamer, MS10-Trunc. This aptamer was characterized by various biochemical, biophysical, and in silico techniques. Its theranostic activity toward Mtb was established using enzyme inhibition, host cell binding, and invasion assays. MS10-Trunc aptamer exhibited high affinity for MS (equilibrium dissociation constant [KD] â¼19 pM) and displayed robust inhibition of MS enzyme activity with IC50 of 251.1 nM and inhibitor constant (Ki) of 230 nM. This aptamer blocked mycobacterial entry into host cells by binding to surface-associated MS. In addition, we have also demonstrated its application in the detection of tuberculous meningitis (TBM) in patients with sensitivity and specificity each of >97%.
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BACKGROUND: Tuberculous meningitis (TBM) is the most devastating manifestation of extra-pulmonary tuberculosis. About 33% of TBM patients die due to very late diagnosis of the disease. Conventional diagnostic methods based on signs and symptoms, cerebrospinal fluid (CSF) smear microscopy or liquid culture suffer from either poor sensitivity or long turnaround time (up to 8 weeks). Therefore, in order to manage the disease efficiently, there is an urgent and unmet need for a rapid and reliable diagnostic test. METHODS: In the current study, to address the diagnostic challenge of TBM, a highly rapid and sensitive structural switching electrochemical aptasensor was developed by combining the electrochemical property of methylene blue (MB) with the molecular recognition ability of a ssDNA aptamer. To demonstrate the clinical diagnostic utility of the developed aptasensor, a blinded study was performed on 81 archived CSF specimens using differential pulse voltammetry. RESULTS: The electrochemical aptasensor developed in the current study can detect as low as 10 pg HspX in CSF background and yields a highly discriminatory response (P<0.0001) for TBM and not-TBM categories with ~95% sensitivity and ~97.5% specificity and has the ability to deliver sample-to-answer in ≤30 minutes. CONCLUSION: In summary, we demonstrate a new aptamer-based electrochemical biosensing strategy by exploiting the target-induced structural switching of H63 SL-2 M6 aptamer and electroactivity of aptamer-tagged MB for the detection of HspX in CSF samples for the diagnosis of TBM. Further, the clinical utility of this sensor could be extended for the diagnosis of other forms of tuberculosis in the near future.
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Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Pruebas Diagnósticas de Rutina/métodos , Técnicas Electroquímicas/métodos , Mycobacterium tuberculosis/genética , Tuberculosis Meníngea/diagnóstico , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , ADN Bacteriano/genética , Humanos , Mycobacterium tuberculosis/inmunología , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis Meníngea/líquido cefalorraquídeo , Tuberculosis Meníngea/microbiologíaRESUMEN
Tuberculous meningitis (TBM) is the most severe manifestation of tuberculosis and its diagnosis remains a challenge even today due to the lack of an adequate test. HspX antigen of Mycobacterium tuberculosis was previously established as a reliable diagnostic biomarker for TBM in an ELISA test format using anti-HspX polyclonal antibodies. Towards overcoming the limitations of batch-to-batch variation and challenges of scalability in antibody generation, we utilized Systematic Evolution of Ligands by EXponential enrichment (SELEX) to develop high affinity DNA aptamers against HspX as an alternative diagnostic reagent. Post-SELEX optimization of the best-performing aptamer candidate, H63, established its derivative H63 SL-2 M6 to be superior to its parent. Aptamer H63 SL-2 M6 displayed a specific and high affinity interaction with HspX (Kd â¼9.0â¯×â¯10-8 M). In an Aptamer Linked Immobilized Sorbent Assay (ALISA), H63 SL-2 M6 significantly differentiated between cerebrospinal fluid specimens from TBM and non-TBM subjects (n = 87, ***p < 0.0001) with â¼100% sensitivity and â¼91% specificity. Notably, ALISA exhibited comparable performance with previously reported antibody-based ELISA and qPCR. Altogether, our findings establish the utility of HspX aptamer for the reliable diagnosis of TBM and pave the way for developing an aptamer-based point-of-care test for TBM.
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Antígenos Bacterianos/líquido cefalorraquídeo , Aptámeros de Nucleótidos/síntesis química , Proteínas Bacterianas/líquido cefalorraquídeo , Mycobacterium tuberculosis/metabolismo , Técnica SELEX de Producción de Aptámeros , Tuberculosis Meníngea/diagnóstico , Antígenos Bacterianos/genética , Aptámeros de Nucleótidos/genética , Aptámeros de Nucleótidos/metabolismo , Proteínas Bacterianas/genética , Biomarcadores/líquido cefalorraquídeo , Estudios de Casos y Controles , Humanos , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Tuberculosis Meníngea/líquido cefalorraquídeo , Tuberculosis Meníngea/microbiologíaRESUMEN
BACKGROUND: Tuberculous meningitis (TBM) is the most common form of neurotuberculosis and the fifth most common form of extrapulmonary TB. Early diagnosis and prompt treatment are the cornerstones of effective disease management. The accurate diagnosis of TBM poses a challenge due to an extensive differential diagnosis, low bacterial load and paucity of cerebrospinal fluid (CSF) especially in children. METHODOLOGY/PRINCIPAL FINDINGS: We describe the utility of ELISA and qPCR for the detection of Mycobacterium tuberculosis (M. tb) proteins (GlcB, HspX, MPT51, Ag85B and PstS1) and DNA for the rapid diagnosis of TBM. CSF filtrates (n = 532) derived from children were classified as 'Definite' TBM (M. tb culture positive, n = 29), 'Probable and Possible' TBM (n = 165) and 'Not-TBM' including other cases of meningitis or neurological disorders (n = 338). ROC curves were generated from ELISA and qPCR data of 'Definite' TBM and Non-Tuberculous infectious meningitis (NTIM) samples and cut-off values were derived to provide ≥ 95% specificity. devR qPCR, GlcB, HspX and PstS1 ELISAs showed 100% (88;100) sensitivity and 96-97% specificity in 'Definite' TBM samples. The application of these cut-offs to 'Probable and Possible' TBM groups yielded excellent sensitivity (98%, 94;99) and specificity (98%, 96;99) for qPCR and for GlcB, HspX and MPT51 antigen ELISAs (sensitivity 92-95% and specificity 93-96%). A test combination of qPCR with GlcB and HspX ELISAs accurately detected all TBM samples at a specificity of ~90%. Logistic regression analysis indicated that these tests significantly added value to the currently used algorithms for TBM diagnosis. CONCLUSIONS: The detection of M. tb GlcB/HspX antigens/devR DNA in CSF is likely to improve the utility of existing algorithms for TBM diagnosis and also hasten the speed of diagnosis.
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Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Malato Sintasa/inmunología , Mycobacterium tuberculosis/metabolismo , Tuberculosis Meníngea/microbiología , Algoritmos , Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Líquido Cefalorraquídeo/metabolismo , Niño , Diagnóstico Diferencial , Ensayo de Inmunoadsorción Enzimática/métodos , Humanos , Malato Sintasa/metabolismo , Reacción en Cadena de la Polimerasa/métodos , Valor Predictivo de las Pruebas , Curva ROC , Proteínas Recombinantes/metabolismo , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Tuberculosis Meníngea/diagnósticoRESUMEN
BACKGROUND: The major intrinsic proteins (MIPs) facilitate the transport of water and neutral solutes across the lipid bilayers. Plant MIPs are believed to be important in cell division and expansion and in water transport properties in response to environmental conditions. More than 30 MIP sequences have been identified in Arabidopsis thaliana, maize and rice. Plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), Nod26-like intrinsic protein (NIPs) and small and basic intrinsic proteins (SIPs) are subfamilies of plant MIPs. Despite sequence diversity, all the experimentally determined structures belonging to the MIP superfamily have the same "hour-glass" fold. RESULTS: We have structurally characterized 39 rice and 31 maize MIPs and compared them with that of Arabidopsis. Homology models of 105 MIPs from all three plant species were built. Structure-based sequence alignments were generated and the residues in the helix-helix interfaces were analyzed. Small residues (Gly/Ala/Ser/Thr) are found to be highly conserved as a group in the helix-helix interface of MIP structures. Individual families sometimes prefer one or another of the residues from this group. The narrow aromatic/arginine (ar/R) selectivity filter in MIPs has been shown to provide an important constriction for solute permeability. Ar/R regions were analyzed and compared between the three plant species. Seventeen TIP, NIP and SIP members from rice and maize have ar/R signatures that are not found in Arabidopsis. A subgroup of rice and maize NIPs has small residues in three of the four positions in the ar/R tetrad, resulting in a wider constriction. These MIP members could transport larger solute molecules. CONCLUSION: Small residues are group-conserved in the helix-helix interface of MIP structures and they seem to be important for close helix-helix interactions. Such conservation might help to preserve the hour-glass fold in MIP structures. Analysis and comparison of ar/R selectivity filters suggest that rice and maize MIPs could transport more diverse solutes than Arabidopsis MIPs. Thus the MIP members show conservation in helix-helix interfaces and diversity in aromatic/arginine selectivity filters. The former is related to structural stability and the later can be linked to functional diversity.