Pediatric neuropathology practice in a low- and middle-income country: capacity building through institutional twinning.

Background: Accurate and precise diagnosis is central to treating central nervous system (CNS) tumors, yet tissue diagnosis is often a neglected focus in low- and middle-income countries (LMICs). Since 2016, the WHO classification of CNS tumors has increasingly incorporated molecular biomarkers into the diagnosis of CNS tumors. While this shift to precision diagnostics promises a high degree of diagnostic accuracy and prognostic precision, it has also resulted in increasing divergence in diagnostic and management practices between LMICs and high-income countries (HICs). Pathologists and laboratory professionals in LMICs lack the proper training and tools to join the molecular diagnostic revolution. We describe the impact of a 7-year long twinning program between Canada and Pakistan on pathology services. Methods: During the study period, 141 challenging cases of pediatric CNS tumors initially diagnosed at Aga Khan University Hospital (AKUH), Karachi, were sent to the Hospital for Sick Children in Toronto, Canada (SickKids), for a second opinion. Each case received histologic review and often immunohistochemical staining and relevant molecular testing. A monthly multidisciplinary online tumor board (MDTB) was conducted to discuss the results with pathologists from both institutions in attendance. Results: Diagnostic discordance was seen in 30 cases. Expert review provided subclassification for 53 cases most notably for diffuse gliomas and medulloblastoma. Poorly differentiated tumors benefited the most from second review, mainly because of the resolving power of specialized immunohistochemical stains, NanoString, and targeted gene panel next-generation sequencing. Collaboration with expert neuropathologists led to validation of over half a dozen immunostains at AKUH facilitating diagnosis of CNS tumors. Conclusions: LMIC-HIC Institutional twinning provides much-needed training and mentorship to pathologists and can help in infrastructure development by adopting and validating new immunohistochemical stains. Persistent unresolved cases indicate that molecular techniques are indispensable in for diagnosis in a minority of cases. The development of affordable alternative molecular techniques may help with these histologically unresolved cases.

Impact of medical school experiences on the career choice of neurosurgery: a cross- sectional study from Pakistan.

BACKGROUND: Pakistan grapples with the issue of an inadequate neurosurgery workforce but the reasons for such a disparity remain uncertain. Previous studies have highlighted how various factors including medical school experiences have an impact on career choice, but no study has delved into the impact of medical school exposure among Pakistani medical students, especially for the field of neurosurgery. This study aims to evaluate the impact of neurosurgery exposure, mentorship, and interest groups on medical students' decision to pursue neurosurgery. METHODS: A national cross-sectional survey was conducted in Pakistan, collecting data from medical students, interns, and medical officers over a one-month period. Ethical approval was obtained from the Ethical Review Committee at Aga Khan University, Pakistan. The data was analyzed using SPSS version 26. RESULTS: Out of 2618 participants, 38.0% were male and 62.0% were female, with an average age of 21.82 years (± 2.65). Among them, only 358 (13.6%) were interested in pursuing neurosurgery as a career, while the remaining 2,260 (86.3%) were not. More females (58.9%) than males (41.1%) expressed interest in pursuing neurosurgery as their intended career. Most medical students interested in pursuing neurosurgery were in the early years of their medical school (1st Year: 19.6%, 2nd Year: 26.0%, 3rd Year: 20.9%). In our study, students from public sector institutions (52.2%) showed more interest in neurosurgery as a career choice compared to those from private sector institutions (44.1%). The main deterrents for choosing neurosurgery were intense training (42.2%), work-life balance (39.9%), limited residency slots (56.7%), medical knowledge (34.1%), and surgical skills (36.6%). CONCLUSION: This study highlights the need for increased student engagement to inculcate the decision to pursue neurosurgery among medical students in Pakistan. A significant gap is highlighted, with the majority of interested students in early years. Public sector students show higher interest than their private sector counterparts. However, barriers like intense training, limited residency slots, and work-life balance concerns influence career choice. Targeted interventions like mentorship programs are crucial for fostering future neurosurgeons and advancing patient care and research. By addressing the identified disparities in experiences and promoting a supportive educational environment, it is possible to cultivate a future generation of skilled and dedicated neurosurgeons who can contribute to advancements in patient care and research in the field.

Exploring the neurosurgery training landscape in Pakistan: A trainee's perspective in resource-limited settings.

Background: Shortage of neurosurgeons in Pakistan, one per 720,000 people, stems from a lack of trainees. Therefore, it is vital to assess the training experience, career opportunities, and satisfaction levels of neurosurgical trainees in Pakistan. Methods: A nationwide survey was conducted, covering 22 CPSP-accredited neurosurgery training programs in Pakistan. Convenience sampling was utilized with a pilot tested questionnaire and responses were analyzed using STATA 15. Results: The response rate was 98% (120/122) with 70.8% male and mean age of 30.4 ± 4.1 years. Training programs included teaching courses (79%) and journal club (66%); however, there was a lack of cadaver workshops (14%) and cranial model-based stimulation (22%). 67% of trainees lacked publications in indexed journals. 69% worked 50-100 h weekly, with 62% experiencing burnout due to workload and hours and a third reporting poor work-life balance. Trainees dedicated more to operating rooms (37%, 10-24 h/week) and clinics (34%, 24-48 h/week) compared to study (42%, <5 h/week) and research (64%, <5 h/week). Gender equality was rated poorly by 50%. Disparities emerged in subspecialty exposure, with over half of trainees lacking exposure to deep brain stimulation (67%), and epilepsy (75%). 52.5% of the training institutes did not offer fellowships and 64.1% of trainees planned to pursue fellowships abroad. Conclusions: Steps need to be taken to improve working hours, gender equity, and increase simulation courses, diversify subspecialty exposure, and promote research initiatives.

Does gender disparity exist in neurosurgery training? Evidence from a nationwide survey from Pakistan.

Gender disparities are prevalent in the neurosurgical field, particularly for female trainees, despite the growing demand for neurosurgeons. The situation is bleaker in low-and middle-income countries, where gender disparities among neurosurgical trainees have not been evaluated. We aimed to gauge the gender differences in opportunities and perceptions of neurosurgery training in Pakistan by comparing responses between males and females. A nationwide web-based survey was conducted in Pakistan, covering 22 College of Physicians and Surgeons of Pakistan (CPSP) accredited neurosurgery training programs. Convenience sampling was used with a pilot-tested questionnaire. Data analysis was performed using SPSS version 26. A total of 120 trainees participated in our survey. The mean age of the participants was 30.4 ± 4.1 years, with 29.2% females and 70.8% males. Concerns about gender equity were more among females (34.3%) than males (27.1%). Poor work-life balance was reported by more females (34.3%) than males (30.6%). Burnout due to working hours was strongly agreed by more females (54.3%) than males (35.3%). More females (40%) acknowledged sufficient mentorship opportunities versus males (25%). Female respondents (65.7%) worked 50-100 hours per week, less than males (69.4%). Satisfaction with surgical exposure was lower among females (2.9%) compared to males (18.8%). More females reported access to teaching courses (82.9% vs. 77.6% males) and neurosurgical conferences (85.7% vs. 80.0% males), cadaver workshops (17.1% vs. 12.9% males), morbidity and mortality meetings (88.6% vs. 82.4% males), case-based sessions (82.9% vs. 75.3% males), and radiology discussions (82.9% vs. 74.1% males). Our study highlights substantial gender gaps in neurosurgical training, concerns over working hours, burnout, mentorship, work-life balance, and gender equity. These findings underscore the necessity for interventions to rectify these disparities and foster gender equity in neurosurgical training.

Gender Differences in Medical Students' Perception of Neurosurgery: A Cross-Sectional Study from Pakistan.

BACKGROUND: Despite 15,000 annual medical graduates, few choose neurosurgery, especially women. The scarcity of female neurosurgeons is a global concern, particularly in resource-limited settings such as Pakistan. This study focuses on gender-based differences in medical student perceptions of neurosurgery in Pakistan. METHODS: A nationwide cross-sectional study was conducted from March 6 to April 20, 2023, using a Web-based survey. Data collectors were recruited through an ambassadorship program, distributed evenly across all provinces. A questionnaire was used after a pilot study. Data analysis was performed using SPSS version 26 and STATA 15. RESULTS: A total of 2353 medical students participated in the study, of which 63.4% were female and 36.5% were male. Around 40.3% of women strongly agreed to the existence of potential gender bias in neurosurgery, in contrast to their corresponding male students, at 17.3%. Some of the highlighted deterring factors in pursuing neurosurgery as a career according to women include longer training duration (44.6%), poor work-life balance (41%), limited residency slots (50.6%), and limited exposure to neurosurgery (45.1%). Other factors included the high-intensity nature of training (33.6%), perceived gender bias (31.4%), competitive work environment (29.1%), complex surgical skills (38.6%), required level of medical knowledge (29.6%), and financial burden (33.9%). CONCLUSIONS: Our study shows that female students are more likely to believe in the existence of potential gender bias in the field compared with their counterpart male participants, which highlights the graveness of the situation in view of the evident paucity of female neurosurgeons in the country.

Intraoperative use of low-field magnetic resonance imaging for brain tumors: A systematic review.

Background: Low-field magnetic resonance imaging (LF-MRI) has become a valuable tool in the diagnosis of brain tumors due to its high spatial resolution and ability to acquire images in a short amount of time. However, the use of LF-MRI for intraoperative imaging during brain tumor surgeries has not been extensively studied. The aim of this systematic review is to investigate the impact of low-field intraoperative magnetic resonance imaging (LF-IMRI) on the duration of brain tumor surgery and the extent of tumor resection. Methods: A comprehensive literature search was conducted using PubMed, Scopus, and Google Scholar from February 2000 to December 2022. The studies were selected based on the inclusion criteria and reviewed independently by two reviewers. The gathered information was organized and analyzed using Excel. Results: Our review of 21 articles found that low-field intraoperative MRI (LF-IMRI) with a field below 0.3T was used in most of the studies, specifically 15 studies used 0.15T LF-IMRI. The T1-weighted sequence was the most frequently reported, and the average scanning time was 24.26 min. The majority of the studies reported a positive impact of LF-IMRI on the extent of tumor resection, with an increase ranging from 11% to 52.5%. Notably, there were no studies describing the use of ultra-low-field (ULF) intraoperative MRI. Conclusion: The results of this systematic review will aid neurosurgeons and neuroradiologists in making informed decisions about the use of LF-MRI in brain tumor surgeries. Further, research is needed to fully understand the impact of LF-MRI in brain tumor surgeries and to optimize its use in the clinical setting. There is an opportunity to study the utility of ULF-MRI in brain tumor surgeries.

Unveiling the potential application of intraoperative brain smear for brain tumor diagnosis in low-middle-income countries: A comprehensive systematic review.

Background: Immediate intraoperative histopathological examination of tumor tissue is indispensable for a neurosurgeon to track surgical resection. A brain smear is a simple, rapid, and cost-effective technique, particularly important in the diagnosis of brain tumors. The study aims to determine the effectiveness of intraoperative brain smear in the diagnosis of brain tumors in low- and middle-income countries (LMICs), while also evaluating its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy. Methods: A comprehensive search of the literature was conducted using PubMed, Scopus, and Google Scholar. The retrieved articles were independently screened by two reviewers. The data was extracted, processed, and organized using Microsoft Excel. Results: A total of 59 out of 553 articles screened were included in the final analysis. The sensitivity and specificity of the intraoperative smear of brain tumors were found to be over 90% in most studies. The PPV was consistently above 90% in 11 studies, reaching 100% in one study and the NPV varied, ranging from 63% to 100%, and the accuracy was found to be >80% in most studies. One recurrent theme in the majority of the included studies was that an intraoperative brain smear is a cost-effective, quick, accessible, and accurate method of diagnosing brain tumors, requiring minimal training and infrastructure. Conclusion: Intraoperative brain smear is a simple, rapid, cost-effective, and highly sensitive diagnostic modality for brain tumors. It can be a viable and accessible alternative to more traditional methods such as frozen sections and can be incorporated into neurosurgical practice in LMICs as a reliable and efficient diagnostic tool.

Factors Delaying the Continuum of Care for the Management of Traumatic Brain Injury in Low- and Middle-Income Countries: A Systematic Review.

BACKGROUND: Considering the disproportionate burden of delayed traumatic brain injury (TBI) management in low- and middle-income countries (LMICs), there is pressing demand for investigations. Therefore, our study aims to evaluate factors delaying the continuum of care for the management of TBIs in LMICs. METHODS: A systematic review was conducted with PubMed, Scopus, Google Scholar and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Observational studies with TBI patients in LMIC were included. The factors affecting management of TBI were extracted and analyzed descriptively. RESULTS: A total of 55 articles were included consisting of 60,603 TBI cases from 18 LMICs. Road traffic accidents (58.7%) were the most common cause of injury. Among included studies, factors contributing to prehospital delays included a poor referral system and lack of an organized system of referral (14%), long travel distances (11%), inadequacy of emergency medical services (16.6%), and self-treatment practices (2.38%). For in-hospital delays, factors such as lack of trained physicians (10%), improper triage systems (20%), and absence of imaging protocols (10%), lack of in-house computed tomography scanners (35%), malfunctioning computed tomography scanners (10%), and a lack of invasive monitoring of intracranial pressure (5%), limited theater space (28%), lack of in-house neurosurgical facilities (28%), absence of in-house neurosurgeons (28%), and financial constraints (14%) were identified. CONCLUSIONS: Several factors, both before and during hospitalization contribute to delays in the management of TBIs in LMICs. Strategically addressing these factors can help overcome delays and improve TBI management in LMICs.

Utilization of an ultra-low-field, portable magnetic resonance imaging for brain tumor assessment in lower middle-income countries.

Background: Access to neuroimaging is limited in low-middle-income countries (LMICs) due to financial and resource constraints. A new, ultra-low-field, low-cost, and portable magnetic resonance imaging (pMRI) device could potentially increase access to imaging in LMICs. Case Description: We have presented the first brain tumor case scanned using an Ultra-low-field pMRI at Aga Khan University Hospital in Karachi, Pakistan. Conclusion: The imaging results suggest that the pMRI device can aid in neuroradiological diagnosis in resource-constrained settings. Further, research is needed to assess its compatibility for imaging other neurological disorders and compare its results with conventional MRI results.

Intraoperative use of ultra-low-field, portable magnetic resonance imaging - first report.

Background: Intraoperative use of portable magnetic resonance imaging (pMRI) has become a valuable tool in a surgeon's arsenal since its inception. It allows intraoperative localization of tumor extent and identification of residual disease, hence maximizing tumor resection. Its utility has been widespread in high-income countries for the past 20 years, but in lower-middle-income countries (LMIC), it is still not widely available due to several reasons, including cost constraints. The use of intraoperative pMRI may be a cost-effective and efficient substitute for conventional MRI machines. The authors present a case where a pMRI device was used intraoperatively in an LMIC setting. Case Description: The authors performed a microscopic transsphenoidal resection of a sellar lesion with intraoperative imaging using the pMRI system on a 45-year-old man with a nonfunctioning pituitary macroadenoma. Without the need for an MRI suite or other MRI-compatible equipment, the scan was conducted within the confinements of a standard operating room. Low-field MRI showed some residual disease and postsurgical changes, comparable to postoperative high-field MRI. Conclusion: To the best of our knowledge, our report provides the first documented successful intraoperative transsphenoidal resection of a pituitary adenoma using an ultra-low-field pMRI device. The device can potentially enhance neurosurgical capacity in resource-constrained settings and improve patient outcomes in developing country.

Risk factors and predictors of intraoperative seizures during awake craniotomy: A systematic review and meta-analysis.

Background: Awake craniotomy (AC) aims to minimize postoperative neurological complications while allowing maximum safe resection. Intraoperative seizures (IOSs) have been a reported complication during AC; however, literature delving into the predictors of IOS remains limited. Therefore, we planned a systematic review and meta-analysis of existing literature to explore predictors of IOS during AC. Methods: From the inception until June 1, 2022, systematic searches of PubMed, Scopus, the Cochrane Library, CINAHL, and Cochrane's Central Register of Controlled Trials were conducted to look for published studies reporting IOS predictors during AC. Results: We found 83 different studies in total; included were six studies with a total of 1815 patients, and 8.4% of them experienced IOSs. The mean age of included patients was 45.3 years, and 38% of the sample was female. Glioma was the most common diagnosis among the patients. A pooled random effect odds ratio (OR) of frontal lobe lesions was 2.42 (95% confidence intervals [CI]: 1.10-5.33, P = 0.03). Those with a pre-existing history of seizures had an OR of 1.80 (95% CI: 1.13-2.87, P = 0.01), and patients on antiepileptic drugs (AEDs) had a pooled OR of 2.47 (95% CI: 1.59-3.85, P < 0.001). Conclusion: Patients with lesions of the frontal lobe, a prior history of seizures, and patients on AEDs are at higher risk of IOSs. These factors should be taken into consideration during the patient's preparation for an AC to avoid an intractable seizure and consequently a failed AC.

Index testing among HIV-positive patients is feasible and successful in identifying additional HIV infections in Pakistan.

OBJECTIVE: To assess the feasibility of index testing approach to test the parents and siblings of human immunodeficiency virus (HIV)-positive children, and identify HIV-positive individuals. METHODS: The study was conducted at Ratodero, Pakistan. Study participants were enrolled from September 2019 to February 2020. The list of HIV-positive persons was provided by the Sindh AIDS Control Programme. Families of 706 HIV-positive persons were approached and all of them agreed to participate. The first test was performed by trained outreach workers. All those with a reactive first test were transported to the nearest health facility for further testing and confirmation. Mothers and siblings were tested at home while additional visits were carried out to reach the fathers. RESULTS: A total of 1766 persons were tested through HIV index testing. Biological siblings accounted for 81% of the contacts. We were able to test 413/463 (89.2%) mothers, 232/413 (56.2%) fathers and 1121/1392 (80.5%) siblings. Out of these, 7 mothers (1.7%) and 22 siblings (2.0%) were confirmed to be HIV-positive, while no one was found to be positive among the fathers. The overall HIV prevalence was 1.6% (29/1766). All HIV-positive persons were guided for treatment and care. CONCLUSIONS: Results indicate that index-testing approach is feasible in Pakistan to expand HIV testing services through home visits.

Prevalence of HIV among pregnant women in three HIV-affected districts in Sindh, Pakistan.

OBJECTIVE: To conduct a community-based cross-sectional survey to determine the prevalence of human immunodeficiency virus (HIV) among pregnant women in taluka Ratodero, Larkana, and two adjacent talukas: Sajawal, district Kambar Shahdadkot and Garhi Yasin, district Shikarpur. METHODS: The study was conducted among pregnant women in the three talukas of rural Sindh: Ratodero, Garhi Yasin, and Sajawal, from October 16, 2020 - December 23, 2020. A total of 1,157 pregnant women were interviewed at their homes and tested using the AlereTM HIV Combo rapid finger prick test. The study captured women's sociodemographic, economic, and health characteristics, including age, education, employment, number of children, home or hospital delivery, antenatal care use, antenatal trimester, history of blood transfusion, and HIV test result. Descriptive statistics were calculated: percentages for categorical variables and mean ± standard deviation (SD) for continuous variables. RESULTS: It was found that 0.35% (4/1,157) of women were HIV-positive, of which 3 were in Ratodero, Larkana, and 1 was in Garhi Yasin, Shikarpur. The average age of women was 28.7 ± 4.0 years. Most of the women (n=1067; 92.2%) did not attend a school, and 99.0% (n=1145) had never had a formal job. The average gestational age was 7.6 (±2.2) months. More than three-quarters of the women participating in the study (n=894; 77.3%) were not registered with a formal healthcare facility for antenatal care. CONCLUSIONS: Considering several HIV sub-epidemics in Larkana in the past decade, HIV infection among pregnant women has remained low in Larkana and adjacent districts.

Intein-mediated recombinant expression of monomeric B22Asp desB30 insulin.

BACKGROUND: Insulin controls hyperglycemia caused by diabetes, and virtually all treatments require exogenous insulin. However, the product's extensive post-translational modifications have hindered the manufacture of recombinant insulin. RESULT: Here we report a novel production method for a monomeric B22Asp desB30 insulin analog (B22D desB30 insulin). Its precursor, DPIP, is fused to an N-terminal chitin-binding domain and intein self-cleavage tag. The fusion protein is expressed and purified from E. coli and immobilized on chitin resins. DPIP is then released using an optimized pH shift and converted to mature insulin via trypsin digest. The resulting product appears monomeric, > 90% pure and devoid of any exogenous enzyme. CONCLUSION: Thus, biologically active insulin analog can be efficiently produced in bacteria and potentially applicable in the treatment of human diabetes.

Comparing the predicted accuracy of PO2\FIO2 ratio with rapid shallow breathing index for successful spontaneous breathing trial in Intensive Care Unit.

OBJECTIVE: To compare the predicted accuracy of PFR with RSBI for successful spontaneous breathing trial before extubation in intensive care unit. METHODS: This cross sectional study was conducted at the ICU of Ch. Pervaiz Ellahi Institute of Cardiology, Multan Medical and Nishtar Medical University Hospital from July, 2017 to January, 2019.PO2/FIO2 and RSBI was measured by a different investigator, before and 20 minutes after the start of SBT. Heart rate, blood pressure and oxygen saturation were continuously measured throughout the trial. Trial outcome was labeled as unsuccessful or successful by the investigator who was blinded to the rapid shallow breathing index and PO2/FiO2 measurements. Patients with SpO2>85%, stable hemodynamics (HR and BP change <20%), stable respiration (RR change <50%), and the absence of (i) signs of labored breathing, (ii) emergence or worsened discomfort, (iii) change in mental status, were labeled as successful in bearing the SBT. Patients were divided into two groups i.e. successful and unsuccessful, gender, Age, GOLD stage, APACHE II score, pCO2, pO2, FiO2 and RSBI score were compared between the two groups after putting all the data in SPSS version 23. Chi square tests and Student's t-test were used on the continuous data and nominal data, accordingly. The specificity, sensitivity, diagnostic accuracy, negative predictive value and positive predictive value of two threshold values of RSBI and PO2/FiO2 ratio were calculated from the 2X2 contingency tables. RESULTS: RSBI threshold of 130 had 40.4% sensitivity, 51.1% specificity, 55.2% positive predictive value, 36.4% negative predictive value and 44.7% diagnostic accuracy while RSBI threshold of 105 had 94.1% sensitivity, 43.6% specificity, 71.4% positive predictive value, 83.2% negative predictive value and 73.8% diagnostic accuracy. pO2/FiO2>250 had 76.9% sensitivity, 24.5% specificity, 60.4% positive predictive value, 41.5% negative predictive value and 55.9% diagnostic accuracy. CONCLUSION: Even though neither rapid shallow breathing nor the PFR was enough accurate in prediction of successful extubation but rapid shallow breathing index 105 threshold had higher sensitivity and specificity as compared to RSBI threshold 130PFR. Therefore, RSBI105 is more accurate in predicting the outcome of extubation of ICU patients.

Ten Year Review of Pulmonary Nocardiosis: A Series of 55 Cases.

Introduction Nocardiosis is a rare opportunistic bacterial infection usually seen in immunosuppressed patients. It is caused by gram-positive, aerobic actinomycetes of the Nocardia genus. The most common site of infection is lungs; but it may affect other organs or even disseminate into blood. Methods In this a 10-year retrospective review, all diagnosed cases of Pulmonary Nocardiosis in a tertiary care hospital were included. The clinical and radiological characteristics, course of complications and lifesaving interventions, and disease outcome were evaluated. Results Among the 55 identified cases, most common risk factor was chronic steroid therapy (n=38; 69.1%). Among respiratory diseases, chronic obstructive pulmonary disease (n=13; 23.6%) and tuberculosis (n=12; 21.8%) were the most common. On chest radiograph, pleural effusion (n=23; 41.8%) and consolidation (n=22; 40.0%) were the common findings. Complications were observed in 32 (58.2%) patients with septicemia and respiratory failure being the most common (n=15; 46.8% in each). Dissemination occurred in 10 (31.2%) patients. The mortality rate of Nocardia is 34.5% (n=19). Conclusion The disease burden of Nocardia is underestimated by clinicians and researchers. Pulmonary Nocardia should always be a differential diagnosis of signs of lower respiratory tract infection and must be excluded in patients not responding to treatment of chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis. Early recognition and individualized management plan can ensure successful recovery.

Production and Partial Characterization of α-Amylase Enzyme from Bacillus sp. BCC 01-50 and Potential Applications.

Amylase is an industrially important enzyme and applied in many industrial processes such as saccharification of starchy materials, food, pharmaceutical, detergent, and textile industries. This research work deals with the optimization of fermentation conditions for α-amylase production from thermophilic bacterial strain Bacillus sp. BCC 01-50 and characterization of crude amylase. The time profile of bacterial growth and amylase production was investigated in synthetic medium and maximum enzyme titer was observed after 60 h. In addition, effects of different carbon sources were tested as a substrate for amylase production and molasses was found to be the best. Various organic and inorganic compounds, potassium nitrate, ammonium chloride, sodium nitrate, urea, yeast extract, tryptone, beef extract, and peptone, were used and beef extract was found to be the best among the nitrogen sources used. Temperature, pH, agitation speed, and size of inoculum were also optimized. Highest enzyme activity was obtained when the strain was cultured in molasses medium for 60 h in shaking incubator (150 rpm) at 50°C and pH 8. Crude amylase showed maximal activity at pH 9 and 65°C. Enzyme remained stable in alkaline pH range 9-10 and 60-70°C. Crude amylase showed great potential for its application in detergent industry and saccharification of starchy materials.

Micro-scale Spatial Clustering of Cholera Risk Factors in Urban Bangladesh.

Close interpersonal contact likely drives spatial clustering of cases of cholera and diarrhea, but spatial clustering of risk factors may also drive this pattern. Few studies have focused specifically on how exposures for disease cluster at small spatial scales. Improving our understanding of the micro-scale clustering of risk factors for cholera may help to target interventions and power studies with cluster designs. We selected sets of spatially matched households (matched-sets) near cholera case households between April and October 2013 in a cholera endemic urban neighborhood of Tongi Township in Bangladesh. We collected data on exposures to suspected cholera risk factors at the household and individual level. We used intra-class correlation coefficients (ICCs) to characterize clustering of exposures within matched-sets and households, and assessed if clustering depended on the geographical extent of the matched-sets. Clustering over larger spatial scales was explored by assessing the relationship between matched-sets. We also explored whether different exposures tended to appear together in individuals, households, and matched-sets. Household level exposures, including: drinking municipal supplied water (ICC = 0.97, 95%CI = 0.96, 0.98), type of latrine (ICC = 0.88, 95%CI = 0.71, 1.00), and intermittent access to drinking water (ICC = 0.96, 95%CI = 0.87, 1.00) exhibited strong clustering within matched-sets. As the geographic extent of matched-sets increased, the concordance of exposures within matched-sets decreased. Concordance between matched-sets of exposures related to water supply was elevated at distances of up to approximately 400 meters. Household level hygiene practices were correlated with infrastructure shown to increase cholera risk. Co-occurrence of different individual level exposures appeared to mostly reflect the differing domestic roles of study participants. Strong spatial clustering of exposures at a small spatial scale in a cholera endemic population suggests a possible role for highly targeted interventions. Studies with cluster designs in areas with strong spatial clustering of exposures should increase sample size to account for the correlation of these exposures.