Development of an HPLC-PDA Method for the Simultaneous Estimation of Three Antibiotics in Pharmaceutical Formulations and Bovine Milk and Health Risk Assessment.

A simple new, rapid, sensitive, and cost-effective HPLC-PDA method was developed and validated for the determination of tetracycline (TC), oxytetracycline (OTC), and ciprofloxacin (CIP) simultaneously. Chromatographic separations were carried out using a reversed-phase Shim-pack GIS C18 column (4.60 × 250.00 mm; 5.00 µm) at 30°C. Oxalic acid (0.05 M), acetonitrile, and methanol were used as mobile phase under gradient elution conditions at the flow rate of 1.50 mL min-1. Detection wavelength was set at 330 nm. An aliquot of 20.00 µL solution was injected, and three drugs were eluted within 7.39 ± 0.05 min. As per ICH guidelines linearity, recovery, accuracy, precision, selectivity, specificity, sensitivity, stability, column efficiency, system suitability, and robustness were determined for the validation of the proposed method. Calibration curves were linear over a studied concentration range of 8.00 µg mL-1 with a correlation coefficient (r) of 0.999 for all drugs. Relative standard deviation (RSD) for intra- and interday precision was found less than 2.87% and 3.22%, respectively, indicating the method to be reproducible. The proposed method has been suitably applied for the estimation of TC, OTC, and CIP in pharmaceutical formulation and milk samples collected from local market in Bangladesh. Among 15 milk samples analyzed, most of the cases (more than 50%) TC, OTC, and CIP were detected above maximum residue levels (MRLs) though no significant toxicological effect on the health of consumers in the study area was identified.

Macroalgae for biomonitoring of trace elements in relation to environmental parameters and seasonality in a sub-tropical mangrove estuary.

Being a resourceful ecosystem, mangrove estuaries have always been subjected to trace elements (TEs) contamination, and therefore, the biomonitoring approach holds immense potential for surveilling the aquatic environment. To investigate the potentiality of mangrove macroalgae as biomonitors, estuarine water, intertidal-sediment, and macroalgal samples were collected from the Pasur River estuary of Sundarbans mangrove ecosystem, Bangladesh, and afterward studied through Atomic Absorption Spectrometer to quantify the levels of six concerned TEs (Fe, Mn, Zn, Cu, Pb, and Cd). This study utilized the geo-environmental and ecological indices and sediment characterization approaches (sediment quality guidelines-SQGs) for assessing the contamination scenario of the adjacent environment to macroalgae whereas the performance of studied algal groups was evaluated using Bio-contamination factor, Comprehensive bio-concentration index, and Metal accumulation index. Metal occurrence scheme in the water followed the order of Fe > Zn > Mn > Pb > Cd while Fe > Mn > Zn > Cu > Pb > Cd for both sediment and macroalgae. Both Pb and Cd exceeded the guideline limit in estuarine water and the indices approach manifested low to moderate contamination with enrichment from anthropogenic origin of Mn, Zn, and Cu in sediment. Moreover, the SQGs revealed rare biological effects of Cu on an aquatic community. Within algal samples, Chlorophyta contributed the highest biomass production, followed by Phaeophyta and Rhodophyta. Statistical relationship disclosed the influence of environmental variables on TE's accumulation in Chlorophyta. By contrast, hydrochemical's association showed prevalence over the TEs accumulation process for Phaeophyta and Rhodophyta. Bioaccumulation performance analysis revealed that the ability to accumulate TEs in macroalgal groups varied with seasons. Therefore, biomonitoring with macroalgae for the region of interest might require further temporal considerations.

Study of purine derivatives and their relation to renal disorders in patients with psoriasis.

BACKGROUND: Psoriasis (Pso) is a chronic proliferative skin condition associated with hyperuricemia that may impair renal function. OBJECTIVES: The current study investigates the correlation between purine derivatives (PDs) and renal function in patients with Pso. PATIENTS/METHODS: This case-control study comprises 30 psoriatic patients and 30 age- and sex-matched healthy controls. The enzyme-linked immunosorbent assay (ELISA) was used to assess serum xanthine oxidase (XO) and urine albumin levels. Serum uric acid (SUA) and urinary creatinine were measured using the colorimetric method. RESULTS: There was a rise in the related PDs levels in patients with Pso compared to controls, as evidenced by the enhanced SUA levels (p < 0.001) and XO levels (p < 0.001). The presence of the related PDs in the serum was linked to the severity of Pso, and there was also a connection between the related PDs levels in the blood and indicators of renal dysfunction. Moreover, SUA and urinary albumin creatinine ratio (UACR) were found to be significantly correlated (r = 0.371 and p = 0.044), as were XO and UACR (r = 0.422 and p = 0.020). In psoriatic patients with itching and palmoplantar affection, mean SUA levels were considerably more significant than those in other instances (p = 0.005 and p = 0.018, respectively). CONCLUSION: Pso, being a hyperproliferative disease, is associated with hyperuricemia, which has a harmful effect on kidney function. The related PDs may be unique serological biomarkers for patients with Pso who are at high risk of developing renal abnormalities, especially with higher severity scores.

GreenMolBD: Nature Derived Bioactive Molecules' Database.

BACKGROUND: One of the essential resources for developing new drugs are naturally derived biologically active lead compounds. Biomedical researchers and pharmaceutical companies are highly interested in these plant-derived molecules to develop the new drug. In this process, collective information of the plants and their phytoconstituents with different properties and descriptors would greatly benefit the researchers to identify the hit, lead or drug-like compound. AIM AND OBJECTIVE: Therefore, the work intended to develop a unique and dynamic database Green- MolBD to provide collective information regarding medicinal plants, such as their profile, chemical constituents, and pharmacological evidence. We also aimed to present information of phytoconstituents, such as in silico description, quantum, drugability and biological target information. METHODS: For data mining, we covered all accessible literature and books, and for in silico analysis, we employed a variety of well-known software and servers. The database is integrated by MySQL, HTML, PHP and JavaScript. RESULTS: GreenMolBD is a freely accessible database and searchable by keywords, plant name, synonym, common name, family name, family synonym, compound name, IUPAC name, InChI Key, target name, and disease name. We have provided a complete profile of individual plants and each compound's physical, quantum, drug likeliness, and toxicity properties (48 type's descriptor) using in silico tools. A total of 1846 associated targets related to 6,864 compounds already explored in different studies are also incorporated and synchronized. CONCLUSION: This is the first evidence-based database of bioactive molecules from medicinal plants specially grown in Bangladesh, which may help explore and foster nature-inspired rational drug discovery.

Mollusc-Derived Brominated Indoles for the Selective Inhibition of Cyclooxygenase: A Computational Expedition.

Inflammation plays an important role in different chronic diseases. Brominated indoles derived from the Australian marine mollusk Dicathais orbita (D. orbita) are of interest for their anti-inflammatory properties. This study evaluates the binding mechanism and potentiality of several brominated indoles (tyrindoxyl sulfate, tyrindoleninone, 6-bromoisatin, and 6,6'-dibromoindirubin) against inflammatory mediators cyclooxygenases-1/2 (COX-1/2) using molecular docking, followed by molecular dynamics simulation, along with physicochemical, drug-likeness, pharmacokinetic (pk), and toxicokinetic (tk) properties. Molecular docking identified that these indole compounds are anchored, with the main amino acid residues, positioned in the binding pocket of the COX-1/2, required for selective inhibition. Moreover, the molecular dynamics simulation based on root mean square deviation (RMSD), radius of gyration (Rg), solvent accessible surface area (SASA), and root mean square fluctuation (RMSF) analyses showed that these natural brominated molecules transit rapidly to a progressive constant configuration during binding with COX-1/2 and seem to accomplish a consistent dynamic behavior by maintaining conformational stability and compactness. The results were comparable to the Food and Drug Administration (FDA)-approved selective COX inhibitor, aspirin. Furthermore, the free energy of binding for the compounds assessed by molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) confirmed the binding capacity of indoles towards COX-1/2, with suitable binding energy values except for the polar precursor tyrindoxyl sulfate (with COX-1). The physicochemical and drug-likeness analysis showed zero violations of Lipinski's rule, and the compounds are predicted to have excellent pharmacokinetic profiles. These indoles are projected to be non-mutagenic and free from hepatotoxicity, with no inhibition of human ether-a-go-go gene (hERG) I inhibitors, and the oral acute toxicity LD50 in rats is predicted to be similar or lower than aspirin. Overall, this work has identified a plausible mechanism for selective COX inhibition by natural marine indoles as potential therapeutic candidates for the mitigation of inflammation.

Insights into the nutritional properties and microbiome diversity in sweet and sour yogurt manufactured in Bangladesh.

Yogurt is one of the most frequently consumed dairy products for nutritional benefits. Although yogurt is enriched with probiotics, it is susceptible to spoilage because of the presence of pathogenic microbes. Spoiled yogurt if consumed can cause food-borne diseases. This study aimed to assess the nutritional composition and microbiome diversity in yogurt manufactured in Bangladesh. Microbial diversity was analyzed through high-throughput sequencing of bacterial 16S rRNA gene and fungal internal transcribed spacer (ITS) region. From nutritional analysis, significantly (P < 0.05) higher pH, fat, moisture, total solid and solid-non-fat contents (%) were observed in sweet yogurt. Following the classification of Illumina sequences, 84.86% and 72.14% of reads were assigned to bacterial and fungal genera, respectively, with significantly higher taxonomic richness in sour yogurt prepared from buffalo. A significant difference in bacterial (Ppermanova = 0.001) and fungal (Ppermanova = 0.013) diversity between sweet and sour yogurt was recorded. A total of 76 bacterial and 70 fungal genera were detected across these samples which were mostly represented by Firmicutes (92.89%) and Ascomycota (98%) phyla, respectively. This is the first study that accentuates nutritional profiles and microbiome diversity of Bangladeshi yogurt which are crucial in determining both active and passive health effects of yogurt consumption in individuals.

Do ward rounds offer effective teaching and training? Obstacles to learning and what makes good teaching in a large tertiary care hospital from trainee doctor's perspective.

Background: Ward rounds (WR) have been integral to the process of teaching and learning medicine and also provides a vital opportunity to communicate with the patient, their relatives, and other healthcare professionals. Yet in recent years trainees' perception of the educational value of WRs seems to have declined. Objectives: The aim of this study to assess trainees' perception of the educational value of WRs at King Abdulaziz Medical City(KAMC), Riyadh, a 1500 bed academic hospital in Saudi Arabia. Methods: A self-administered, paper-based survey was distributed to physicians in training at KAMC between October and December 2019. All residents who attended WRs were invited to participate. The questionnaire was adapted from a survey used in a previous study. The demographic section requested details of the respondent's age, gender, specialty, and seniority. The second and third sections asked about the logistics of current ward round practices. It included several questions on the structure as well as the duration and frequency of ward rounds. The fourth and fifth sections asked for participant's perception of the opportunities for, and the obstacles to, learning on ward rounds. The subsequent sections asked several questions onward round structure and the clinical teacher. Responses were requested on a 5-point Likert-type scale (strongly disagree, disagree, neutral, agree, strongly agree). The last section asked the participant for general comments and feedback Result: The study targeted 250 residents in specialties that routinely performed WRs. Only 166 residents returned the questionnaire (response rate of 66.4%). Male 89 (53.6%), medical 108 (65.1%), surgical 58 (34.9%), resident in first year 81 (48.8%). The overall average time spent on WR was 13 (± 11 SD) hours per week. The WR was perceived as a good opportunity to learn about diagnostic investigation 138 (83%) and patient management 133(80.1%), history taking114 (68.7%) physical examination 103 (62.0%), and time management skills 86 (51.8%). The majority of our trainees felt that the WR was educationally very useful to 86 (52%) and attribute to at least a third of the education they receive during their training. They also reported that about the quarter of the time spent on WRs is devoted to teaching. The good teacher described as enthusiastic to teach 137 (82.5%), provide feedback to trainees 135 (81%), do not rush 139(83.7), communicate to trainee 144 (86.7), and consultant level,101 (60.8). Trainees also identify a few factors that hinder their training such as lack of time 130 (79%), and the number of patients 129 (78.3). Conclusion: This study identifies the strengths and weaknesses of WR in our institution. Finding will help training supervisors in addressing and rectifying these shortcoming and factors hinder training.

A cohort study on the association of MDM2 SNP309 with lung cancer risk in Bangladeshi population.

BACKGROUND/AIMS: Bangladesh is a densely populated country with an increased incidence of lung cancer, mostly due to smoking. Therefore, elucidating the association of mouse double minute 2 homolog (MDM2) single nucleotide polymorphism (SNP) 309 (rs2279744) with lung cancer risk from smoking in Bangladeshi population has become necessary. METHODS: DNA was extracted from blood samples of 126 lung cancer patient and 133 healthy controls. The MDM2 SNP309 was genotyped by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP), using the restriction enzymes MspA1I. Logistic regression was then carried out to calculate odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the risk of lung cancer. A meta-analysis of SNP309 was also carried out on 12,758 control subjects and 11,638 patient subjects. RESULTS: In multivariate logistic regression, significantly increased risk of lung cancer was observed for MDM2 SNP309 in the dominant model (TG + GG vs. TT: OR, 2.13; 95% CI, 1.29 to 3.53). Stratification analysis revealed that age, sex, obesity, and smoking also increases the risk of lung cancer when carrying the MDM2 SNP309. Our meta-analysis revealed that MDM2 SNP309 was considerably associated with lung cancer in Asian populations (TG + GG vs. TT: OR, 1.32; 95% CI , 1.12 to 1.56; p = 0.019 for heterogeneity). CONCLUSION: The MDM2 SNP309 was associated with high risk of lung cancer in Bangladeshi and Asian population, particularly with increased age, smoking, and body mass index.

Extracorporeal Shock Wave-Supported Adipose-Derived Fresh Stromal Vascular Fraction Preserved Left Ventricular (LV) Function and Inhibited LV Remodeling in Acute Myocardial Infarction in Rat.

This study tested the hypothesis that extracorporeal shock wave- (ECSW-) assisted adipose-derived stromal vascular fraction (SVF) therapy could preserve left ventricular ejection fraction (LVEF) and inhibit LV remodeling in a rat after acute myocardial infarction (AMI). Adult male SD rats were categorized into group 1 (sham control), group 2 (AMI induced by left coronary artery ligation), group 3 [AMI + ECSW (280 impulses at 0.1 mJ/mm2, applied to the chest wall at 3 h, days 3 and 7 after AMI), group 4 [AMI + SVF (1.2 × 106) implanted into the infarct area at 3 h after AMI], and group 5 (AMI + ECSW-SVF). In vitro, SVF protected H9C2 cells against menadione-induced mitochondrial damage and increased fluorescent intensity of mitochondria in nuclei (p < 0.01). By day 42 after AMI, LVEF was highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, and similar between the latter two groups (all p < 0.0001). LV remodeling and infarcted, fibrotic, and collagen deposition areas as well as apoptotic nuclei exhibited an opposite pattern to LVEF among the groups (all p < 0.0001). Protein expressions of CD31/vWF/eNOS/PGC-1α/α-MHC/mitochondrial cytochrome C exhibited an identical pattern, whilst protein expressions of MMP-9/TNF-α/IL-1ß/NF-κB/caspase-3/PARP/Samd3/TGF-ß/NOX-1/NOX-2/oxidized protein/ß-MHC/BNP exhibited an opposite pattern to LVEF among five groups (all p < 0.0001). Cellular expressions of CXCR4/SDF-1α/Sca-1/c-Kit significantly and progressively increased from groups 1 to 5 (all p < 0.0001). Cellular expression of γ-H2AX/CD68 displayed an opposite pattern to LVEF among the five groups (all p < 0.0001). In conclusion, ECSW-SVF therapy effectively preserved LVEF and inhibited LV remodeling in rat AMI.

Effect of Dexmedetomidine Versus Nalbuphine as an Adjuvant on Paravertebral Block to Manage Postoperative Pain After Mastectomies.

BACKGROUND AND OBJECTIVE: Breast cancer is the commonest cancer in women worldwide. Many patients are frequently admitted to the operating theaters for mastectomies. Thoracic paravertebral block (PVB) is increasingly used as an effective means for post-operative pain relief. The present study aimed at evaluating the effectiveness and safety of dexmedetomidine and nalbuphine as an adjuvant to bupivacaine local anesthetic in thoracic paravertebral block in breast cancer surgeries. METHODS: A total of 60 female patients aged 18 to 78 were included in the study, and ASA I, II, III were scheduled for mastectomy. These patients were unsystematically assigned into three 20-member groups: group PB received bupivacaine (0.3 mL/ kg) + 1 mL (0.9% sodium chloride) normal saline; group PBD received bupivacaine (0.3 mL/kg) + dexmedetomidine 1 µg/kg; and Group PBN received bupivacaine (0.3 mL/kg) and 10 mg (1 mL) nalbuphine. Demographic data, intraoperative SPO2, ETCO2, HR, SBP and DBP, pain scores (at rest and movement), and sedation scores were recorded every 30 minutes during the initial 2 hours and 4, 8, 24, and 48 hours from T0. Also, postoperative tramadol consumption, the time to the first analgesic request, and any complications were also recorded. RESULTS: There were no statistically significant differences among the three groups regarding demographic data, SPO2, ETCO2, HR, SBP and DBP intraoperatively. Moreover, no significant difference was found in HR, SBP and DBP postoperatively. Postoperative pain scores were significantly higher in group BP, whether at rest or movement. The sedation was significantly higher in PBD group in the first 12 hours postoperatively. There was a significantly lower postoperative tramadol consumption in PBN group and a significantly longer time to the first analgesic request than other groups. No complications were reported in any group. CONCLUSIONS: Addition of nalbuphine 10 mg as an adjuvant to bupivacaine local anesthetic in PVB improved the quality of the block and decreased postoperative analgesic requirements than the bupivacaine only group and dexmedetomidine and bupivacaine group. However, adding dexmedetomidine to bupivacaine increased the time to the first analgesic request and more sedation than bupivacaine and bupivacaine and nalbuphine.

Histopathology of Cervical Cancer and Arsenic Concentration in Well Water: An Ecological Analysis.

Arsenic in drinking water is causally linked with cancer of the skin, lung, and urinary bladder, but there is very little data on a possible role for arsenic in the etiology of cervical cancer, a disease in which human papilloma virus is held to be a necessary but not sufficient cause. All histopathology results from cervical specimens from the National Institute of Cancer Research and Hospital (NICRH), Dhaka (1997-2015), and the Anowara Medical Services (2003-2015), both serving the whole of Bangladesh, were classified by cell type. Arsenic concentrations in well water in the thana of residence were estimated from systematic sampling carried out by the British Geological Survey. In a case-referent analysis arsenic estimates for cases of cervical cancer were compared with those found to have benign lesions. In this study, 3464 NICRH (CH) cervical specimens and 30,050 community medical service (CMS) specimens were available: 3329 (CH) and 899 (CMS) were recorded as malignant. Most were squamous cell carcinoma, of which 4.9% were poorly differentiated. Overall, there was no increase in cervical cancer with increasing arsenic concentration. Among those with squamous cell histology, a strong dose response was seen for poorly differentiated cancer with increasing arsenic exposure. The odds ratio increased monotonically, compared with exposure <10 µg/L, from 1.58 at 10 < 50 µg/L to 8.11 at >200 µg/L (p < 0.001). Given the high proportion of Bangladeshis using drinking water containing >50 µg/L of arsenic, the evidence that arsenic is implicated in cancer grade suggests a need for further investigation and the introduction of cervical screening in high arsenic areas.

Feasibility and Safety of Transulnar Catheterization in Ipsilateral Radial Artery Occlusion.

To investigate the postprocedural cardiovascular events and vascular outcomes, including hand ischemia and neurological compromise, after transulnar (TU) catheterization in ipsilateral radial artery occlusion.Previous randomized trials have shown that the transulnar (TU) approach for coronary angiogram and intervention has safety and outcomes similar to those of the transradial (TR) approach. However, the safety of the TU procedure when ipsilateral radial artery occlusion occurs is unknown.We retrospectively reviewed 87 TU cases with ipsilateral radial artery occlusion confirmed by a forearm angiogram. Eighty percent of these patients had a history of ipsilateral radial artery cannulation or surgery. We avoided the use of over-sized sheaths or applied a sheathless approach during surgery.No ulnar artery occlusion was observed by subsequent Doppler ultrasound or pulse oximetry. No patient developed hand ischemia or serious complications requiring surgery or blood transfusion during the follow-up period of 32.2 ± 24.0 months. Review of the preprocedural forearm angiograms showed that 95.7% of the patients possessed significant collaterals supplying flow from the interosseous artery to the occluded radial artery remnant. Thus, the blood circulation to the palmar arch and digital vessels was maintained even when the ulnar artery was temporarily occluded by an in-dwelling ulnar arterial sheath.TU catheterization was safe in patients with coexisting ipsilateral radial artery occlusions and feasible for use in complex intervention procedures. Cautious manipulation of ulnar artery cannulation and hemostasis helped decrease the risk of hand ischemia.

Timing and Outcome of Referral to the First Stand-Alone Palliative Care Center in the Eastern Mediterranean Region, the Palliative Care Center of Kuwait.

BACKGROUND: Compared to other regions of the world, palliative care (PC) in the Eastern Mediterranean region is at an earlier stage of development. The Palliative Care Center of Kuwait (PCC-K) was established a few years ago as the first stand-alone PC center in the region. This study was conducted to investigate the timing of referral to the PCC-K and its outcome. METHODS: Retrospective review of referrals to the PCC-K during its first 3 years of action. Late referral was defined as referral during the last 30 days of life. RESULTS: During the 3-year period, 498 patients with cancer were referred to the PCC-K of whom 467 were eligible for analysis. Referral was considered late in 58% of patients. Nononcology facilities were more likely to refer patients late when compared to oncology facilities ( P = .033). The palliative performance scale (PPS) was ≤30 in 59% of late referrals and 21% in earlier referrals ( P < .001). Among 467 referred patients, 342 (73%) were eligible for transfer to the PCC-K, 102 (22%) were ineligible, and 23 (5%) died before assessment by the PCC-K consultation team. From the 342 eligible patients, the family caregivers refused the transfer of 64 (19%) patients to the PCC-K. CONCLUSION: Patients are frequently referred late to the PCC-K. Further research to identify barriers to PC and its early integration in Kuwait is required. The PPS may be useful in identifying late referrals.

Luteal versus follicular phase surgical oophorectomy plus tamoxifen in premenopausal women with metastatic hormone receptor-positive breast cancer.

PURPOSE: In premenopausal women with metastatic hormone receptor-positive breast cancer, hormonal therapy is the first-line therapy. Gonadotropin-releasing hormone analogue + tamoxifen therapies have been found to be more effective. The pattern of recurrence risk over time after primary surgery suggests that peri-operative factors impact recurrence. Secondary analyses of an adjuvant trial suggested that the luteal phase timing of surgical oophorectomy in the menstrual cycle simultaneous with primary breast surgery favourably influenced long-term outcomes. METHODS: Two hundred forty-nine premenopausal women with incurable or metastatic hormone receptor-positive breast cancer entered a trial in which they were randomised to historical mid-luteal or mid-follicular phase surgical oophorectomy followed by oral tamoxifen treatment. Kaplan-Meier methods, the log-rank test, and multivariable Cox regression models were used to assess overall and progression-free survival (PFS) in the two randomised groups and by hormone-confirmed menstrual cycle phase. RESULTS: Overall survival (OS) and PFS were not demonstrated to be different in the two randomised groups. In a secondary analysis, OS appeared worse in luteal phase surgery patients with progesterone levels <2 ng/ml (anovulatory patients; adjusted hazard ratio 1.46, 95% confidence interval [CI]: 0.89-2.41, p = 0.14) compared with those in luteal phase with progesterone level of 2 ng/ml or higher. Median OS was 2 years (95% CI: 1.7-2.3) and OS at 4 years was 26%. CONCLUSIONS: The history-based timing of surgical oophorectomy in the menstrual cycle did not influence outcomes in this trial of metastatic patients. ClinicalTrials.gov number NCT00293540.

Arsenic in Drinking Water, Transition Cell Cancer and Chronic Cystitis in Rural Bangladesh.

In earlier analyses, we demonstrated dose-response relationships between renal and lung cancer and local arsenic concentrations in wells used by Bangladeshi villagers. We used the same case-referent approach to examine the relation of arsenic to biopsy confirmed transition cell cancer (TCC) of the ureter, bladder or urethra in these villagers. As the International Agency for Research on Cancer (IARC) has conclude that arsenic in drinking water causes bladder cancer, we expected to find higher risk with increasing arsenic concentration. We used histology/cytology results from biopsies carried out at a single clinic in Dhaka, Bangladesh from January 2008 to October 2011. We classified these into four groups, TCC (n = 1466), other malignancies (n = 145), chronic cystitis (CC) (n = 844) and other benign (n = 194). Arsenic concentration was estimated from British Geological Survey reports. Odds ratios were calculated by multilevel logistic regression adjusted for confounding and allowing for geographic clustering. We found no consistent trend for TCC with increasing arsenic concentration but the likelihood of a patient with benign disease having CC was significantly increased at arsenic concentrations >100 µg/L. We conclude that the expected relationship of TCC to arsenic was masked by over-matching that resulted from the previously unreported relationship between arsenic and CC. We hypothesize that CC may be a precursor of TCC in high arsenic areas.

Risk Factors for Premenopausal Breast Cancer in Bangladesh.

Background. The incidence of premenopausal breast cancer is rising throughout South Asia. Our objective was to determine the role of risk factors associated with Westernization for premenopausal breast cancer in Bangladesh. Methods. We conducted a matched case-control study between January 1, 2007, and December 31, 2010, at four hospitals in Bangladesh. Cases were premenopausal women diagnosed with invasive breast cancer. Controls were premenopausal women with no personal history of breast cancer. Logistic regression was used to calculate the odds ratios (OR) for breast cancer. Results. We identified 129 age-matched pairs. The mean age of breast cancer diagnosis was 37.5 years. Each year decrease in the age of menarche significantly increased the risk of breast cancer (OR = 1.67, 95% CI 1.09-2.56, P = 0.02). The risk was also increased with a current body mass index of ≥25 kg/m(2) (OR = 5.24, 95% CI 1.10-24.9, P = 0.04). Age at first childbirth, parity, and breastfeeding were not significantly associated with premenopausal breast cancer risk (P > 0.05). Conclusions. Age at menarche and adult weight gain were associated with premenopausal breast cancer risk. Other factors associated with Westernization may not be relevant to premenopausal breast cancer risk in Bangladesh.

Thermally induced phase mismatching in a repetitively Gaussian pulsed pumping KTP crystal: a spatiotemporal treatment.

Thermally induced phase mismatching (TIPM) has been proven to be an influential issue in nonlinear phenomena. It occurs when refractive indices of crystal are changed due to temperature rise. In this work, the authors report on a modeling of spatiotemporal dependence of TIPM in a repetitively pulsed pumping KTP crystal. Gaussian profiles for both spatial and temporal dependences of pump beam were used to generate second-harmonic waves in a type II configuration. This modeling is of importance in predicting the nonlinear conversion efficiency of crystals when heat is loaded in the system. To this end, at first, an approach to solve the heat equation in a repetitively pulsed pumping system with consideration of the temperature dependence of thermal conductivity and realistic cooling mechanisms such as conduction, convection, and radiation, is presented. The TIPM is then calculated through the use of experimental thermal dispersion relations of KTP crystal. The results show how accumulative behaviors of temperature and TIPM (with its reverse sign) happen when the number of pulses is increased. Fluctuations accompanying temperature and TIPM were observed which were attributed to the off-time between successive pulses. Moreover, in this work, a numerical procedure for solving a repetitively pulsed pumped crystal is introduced. This procedure enables us to solve the problem with home-used computing machines.

Temperature increase effects on a double-pass cavity type II second-harmonic generation: a model for depleted Gaussian continuous waves.

In this work, the effect of temperature increase on the efficiency of a double-pass cavity type II second-harmonic generation (SHG) is investigated. To this end, a depleted wave model describing the continuous-wave SHG process with fundamental Gaussian waves was developed. First, six coupled equations were proposed to model a double-pass cavity to generate the second harmonic of a Gaussian fundamental wave in type II configuration. Then, the effect of temperature increase in the nonlinear crystal due to the optical absorption was modeled. To do this, a mismatched phase arising from changes in refractive indices was added to the coupled equations. Although the nondepleted assumption is usually used in such problems, a simultaneous solving of coupled equations with assumption of fundamental beam depletion was performed. The results were obtained by a homemade code written in Intel Fortran, and show how the efficiency of the SHG process decreases when the crystal is warmed up by 5, 10, and 15 K. Dramatic reductions in SHG efficiency were observed due to small changes in temperature. The results show excellent agreement with the experimental data [Opt. Commun.173, 311-314 (2000)].

Complete anisotropic time-dependent heat equation in KTP crystal under repetitively pulsed Gaussian beams: a numerical approach.

In this work, a thorough and detailed solution for the time-dependent heat equation for a cylindrical nonlinear potassium titanyl phosphate (KTP) crystal under a repetitively pulsed pumping source is developed. The convection and radiation boundary conditions, which are usually ignored in the literature, have been taken into account, and their importance on the temperature distribution has been discussed in detail. Moreover, the temperature dependence of thermal conductivity of KTP was considered in the calculations, and its impact is discussed. It is shown that the radiation term has a negligible effect and can be dropped safely, while the temperature dependence of thermal conductivity is more influential, such that ignorance of it brings some errors into the modeling. The time evolution of the temperature while the crystal is pumping with a train of successive Gaussian pulses until reaching equilibrium is shown. To accomplish numerical calculations, we developed a homemade code written with the finite difference time domain method in Intel Fortran (ifort) and ran it with the Linux operating system.