Analysis of Socio Demographic Risk Factors of Cervical Intraepithelial Neoplasia at Colposcopic Clinic in Mymensingh Medical College Hospital

Cervical intraepithelial neoplasia (CIN) is a pre-malignant lesion of the cervix of uterus. Several risk factors increased the risk of developing CIN. Purpose of this study was to evaluate the socio-demographic risk factors related to CIN at our setting. This Cross sectional observational study was performed at Colposcopic clinic of Mymensingh Medical College Hospital (MMCH), Mymensingh, Bangladesh from 9th November 2017 to 8th May 2018. Overall demographic features of 50 patients of precancerous cervical lesion show that, most of the patients belonged to the age group 30-39 years (46.0%), mean age was 32.7±10.3 years. Maximum numbers of respondents came from rural area (58.0%), followed by urban area (42.0%). Among them house wife- 46.0%, daily worker- 30.0% and illiterate 36.0%, primary level of education 32.6%. Among the patients the poor class 46.0% and 58.0% of the respondents were married at age ≤19 year. Among the respondents, (26.0%) were conceived their first child 1 month after their marriage and 54.0% of the women within 12 months of marriage. In this study multipara were (62.0%). Oral contraceptive pill was taken by (42.0%) of patients. The association of risk factors revealed that betel or tobacco chewing present in 28.0% cases; history of menstrual regulation (MR), dilatation, evacuation and curettage (DE&C), miscarriage were in 26.0% cases, family history of cancer were in 16.0% cases and multiple sexual exposure was in 10.0% cases. Women develop pre-malignant cervical lesions require early treatment. It is recommended that provision of proper health care support, early detection of CIN and proper management, can reduce the fatal outcome of the disease.

Relaparotomy after Cesarean Section: Experience in a Tertiary Referral Hospital

This study was aimed at exploring the causes of relaparotomy following caesarean section. The surgical procedures performed during relaparotomy were also discussed. This was a prospective study conducted in the Department of Obstetrics and Gynaecology, Mymensingh Medical College Hospital (MMCH), Mymensingh, Bangladesh from November 2020 to May 2021. MMCH is the largest referral Hospital in Mymensingh. During this study period 48 puerpera needed relaparotomy after caesarean section within 6 weeks of caesarean section. The frequency of relaparotomy was 2.6%. Of the 48 cases, 28(58.33%) cases needed relaparotomy due to post partum haemorrhage (PPH). Among them 9(18.75%) had primary PPH, 19(39.58%) patients had secondary PPH. Here 7(14.58%) patients suffered from sub rectus hematoma, 5(10.42%) patients had puerperal sepsis, 3(6.23%) had internal haemorrhage and 4(8.33%) women had wound dehiscence. Foreign body was removed in 1 case (2.08%). Main procedure performed was subtotal (45.83%) and total hysterectomy (25%). Coagulation failure and septicaemia were causes of maternal death. Case fatality rate was 4.17%. Obstetric patients who need relaparotomy face potential death. This study will help us to identify the causes for relaparotomy. Due precautions should be taken as far as possible to avoid this complications following caesarean section and thereby reduce maternal mortality and morbidity.

Clinical and Liver Enzymes among the Patients with Metabolic Syndrome with or without Non Alcoholic Fatty Liver Disease attending a Tertiary Care Hospital

Metabolic syndrome is characterized by central obesity, dyslipidemia, raised blood pressure and impaired blood sugar levels. Patients with metabolic syndrome are at increased risk of type 2 diabetes and atherosclerotic cardiovascular disease. This cross-sectional observational study was carried out from January 2019 to December 2019 at the inpatient and outpatient department of BIRDEM General Hospital, Dhaka, Bangladesh. Adult subjects aged ≥18 years with metabolic syndrome (IDF criteria, 2006) were included and purposive sampling was done. A total of 242 participants were included and the mean age was 40.2±14.1 years ranging from 18-70 years. Among them, 140(57.85%) were female and 102(42.15%) were male. Out of 242 participants, 170(70.25%) subjects had Metabolic Syndrome (MetS) with Non-Alcoholic Fatty Liver (NAFLD) and 72(29.75%) subjects had metabolic syndrome without NAFLD. In the male participants, the mean waist-hip ratio (WHR) of MetS with NAFLD and MetS without NAFLD was 1.01±0.07 vs. 0.96±0.08 respectively (p-value 0.003). In female subjects, the mean waist-hip ratio (WHR) of MetS with NAFLD and MetS without NAFLD group was 0.90±0.10 vs. 0.86±0.08 respectively (p-value 0.026). MetS with NAFLD subjects were more hypertensive than MetS without NAFLD subjects (61.2% vs. 42.7%). In the MetS with NAFLD group (n=170), 11.8% was normoglycemic, 43.5% was prediabetic and 44.7% was diabetic. In the MetS without NAFLD group (n=72), 19.5% was normoglycemic, 50% was prediabetic and 30.5% was diabetic. SGPT value was significantly raised in MetS with NAFLD subjects (56.4%) than MetS without NAFLD (38.9%) subjects (p-value 0.038). SGOT value was significantly raised in MetS with NAFLD subjects (58.8%) than MetS without NAFLD subjects (41.7%); (p-value 0.005). Mean Total Cholesterol and Triglyceride were significantly raised in MetS with NAFLD subjects than MetS without NAFLD subjects (p-value 0.01). In Subjects with grade I fatty liver, mean SGPT and SGOT were 42.27±22.31 vs. 39.59±16.93 respectively. In Subjects with grade II fatty liver, mean SGPT and SGOT were 62.13±32.42 vs. 52.45±28.56 respectively. In grade III fatty liver, mean SGPT and SGOT were 51.50±32.19 vs. 41.00±17.52 respectively (p value <0.001). More than two-third of participants with metabolic syndrome had non-alcoholic fatty liver disease (NAFLD) and a significant elevation of liver enzymes than metabolic syndrome without NAFLD participants. About 85.0% of metabolic syndrome participants had glucose intolerance in the form of prediabetes and diabetes.

Moderate Rainfall and High Humidity During the Monsoon Season, Negligence in Using Malaria Protection Methods and High Proportion of Mild Symptomatic Patients Were the Driving Forces for Upsurge of Malaria Cases in 2018 Among Tea Tribe Populations in Endemic Dolonibasti Health Sub-center, Udalguri District, Assam State, North-East India

Malaria elimination is a global priority, which India has also adopted as a target. Despite the malaria control efforts like long-lasting insecticidal nets distribution, rounds of indoor residual spray, the introduction of bi-valent rapid diagnostic tests and artemisinin combination therapy, malaria remained consistent in Dolonibasti sub-center of Orang block primary health center (BPHC) under the district Udalguri, Assam state followed by abrupt rise in cases in 2018. Therefore, we aimed to investigate the factors driving the malaria transmission in the outbreak area of Dolonibasti sub-center. Malaria epidemiological data (2008–2018) of Udalguri district and Orang BPHC was collected. The annual (2011-2018) and monthly (2013–2018) malaria and meteorological data of Dolonibasti sub-center was collected. An entomological survey, Knowledge, Attitude and Practices study among malaria cases (n = 120) from Dolonibasti was conducted. In 2018, 26.1 % (2136/ 8188) of the population of Dolonibasti were found to be malaria positive, of which 55% were adults (n = 1176). Majority of cases were from tea tribe populations (90%), either asymptomatic or with fever only, 67.5 % (81/120) had experienced malaria infection during past years. The outbreak was characterized by a strong increase in cases in June 2018, high proportion of slide falciparum rate of 26.1% (other years average, 15.8%) and high proportion of P. falciparum of 81.2 % (other years average, 84.3%). Anopheles minimus s.l. was the major vector with 28.6% positivity and high larval density in paddy fields/ drainage area. Annual relative humidity was associated with rise in malaria cases, annual parasite incidence (r_s = 0.69, 90%CI; p = 0.06) and slide positivity rate (r_s = 0.83, 95%CI; p = 0.01). Older people were less educated (r_s = −0.66; p < 0.001), had lesser knowledge about malaria cause (r_s = −0.42; χ²=21.80; p < 0.001) and prevention (r_s = −0.18; p = 0.04). Malaria control practices were followed by those having knowledge about cause of malaria (r_s = 0.36; χ² = 13.50; p < 0.001) and prevention (r_s = 0.40; χ² = 17.71; p < 0.001). Altogether, 84.6% (44/52) of the respondents did not use protective measures. We described a sudden increase in malaria incidence in a rural, predominantly tea tribe population group with high illiteracy rate and ignorance on protective measures against malaria. More efforts that are concerted needed to educate the community about malaria control practices.

Baseline assessment of water quality and ecological indicators in Penaeus vannamei farm wastewater along the Southeast coast of India

The present study aimed to investigate the water quality characteristics and the ecological indicators of wastewater of white legged shrimp Penaeus vannamei ponds along the Southeast coast of India. The wastewater samples were collected from 15 shrimp farms covering 11 districts located along the coastal line of Tamil Nadu and Puducherry, India. By adopting standard methods, the collected samples were subjected to analyses of physico-chemical and biological characteristics, especially the microbial load and metal and plankton composition. The nitrate-nitrogen, ammonia-nitrogen, THB, TCB, and Cu concentrations of the samples were found to exceed the permissible limit as recommended by WHO, USEPA, CPCB, and CAA. Principal component analysis and canonical correspondence analysis have suggested that the phosphate, nitrate, silicate, ammonia, and total phosphorus are the important chemical factors. The generated data would be of interest to farmers for their shrimp crop management vis-à-vis culture pond wastewater treatment.

Experience of Chikungunya in a Chikungunya Clinic at Tertiary Medical College Hospital in Bangladesh

A large outbreak of Chikungunya occurred in Bangladesh in 2017. It caused a serious impact on sufferers of the disease. Study aimed to assess the real scenario unfolding as case reporting to Directorate General of Health is less in Bangladesh by physicians. For this observational study a Chikungunya Clinic was set at Dhaka Medical College, Dhaka, Bangladesh and physicians were attached to the clinic who got training on Chikungunya by directorate General of Health from 9th July 2017 to 10th September 2017. A pre-tested questionnaire was supplied to all the physicians working at the clinic. Appropriate training was provided before data collection. Total 301 patients were enrolled. Most striking features were fever (99.3%), arthralgia (99.3%), rash 70.4%, Itching 64.8%, oral ulcer 23.9%, loose motion 18.6% and bleeding 8%.%. Most affected joints were MCP 76.9%, knee 74.9%, wrist 69.2%, Inter phalangeal joints of hand were 67.2%. Chikungunya was not very familiar with the physicians of Bangladesh. This was first time large scale experience by physicians of Bangladesh. Severity and chronicity of arthritis, rash, bleeding caused serious morbidity.

Iron Deficiency and Iron Deficiency Anemia in Women with Bronchial Asthma

This case control study was conducted in the out patient department (OPD), Enam Medical College & Hospital (EMCH), Dhaka, Bangladesh from 1st January 2017 to 31st December 2017. The aim of our study was to find the possible association between serum iron state and iron deficiency anemia with bronchial asthma in women. We investigated 40 diagnosed female cases of well controlled bronchial asthma and 20 healthy female as control. In both groups complete blood count (CBC) with peripheral smear was done, C-reactive protein (CRP), serum iron, serum ferritin, and serum total iron binding capacity (TIBC) was measured. We found asthma cases had lower hemoglobin than control (mean±SD 10.92±1.34 vs. 12.30±0.73, p value 0.013), serum iron and serum ferritin were significantly lower (p value 0.016 and 0.000 respectively) and TIBC was higher (p value 0.000) in asthmatic cases as compared to controls. Non anemic asthmatics showed significant lower serum ferritin compared with non-anemic healthy controls (p value 0.005). So we conclude that iron deficiency anemia is more prevalent in asthmatic women as compared to healthy controls.

Seasonal Pattern of Pathogenic V. cholerae and V. paraheamolyticus in Surface Water of Dhaka, Bangladesh

V. cholerae and V. parahaemolyticus are responsible for majority of the Vibrio-related infections world wide. In this observational study, we selected three important river and pondsites of Dhaka city, Bangladesh to observe the presence of pathogenic V. cholerae, and V. parahaemolyticus. Surface water samples were collected from July 2013 to April 2014. Identification of V. cholerae was confirmed by the presence of ompW gene by PCR. Vibrio cholerae was found in the unique dual peak (March to May and September to November) patternin Mirpur-1 Mazar pond and Abdullahpur bridge river site, like many other studies reported earlier in Dhaka with only one exception of finding V. cholerae in the month of July 2013 in Mirpur-1 Mazar pond. A single peak was found from September to November in Mirpur-1 river sites. The ctxB positive non- O1 V. cholerae has also been reported. The presence of ctxB gene was observed by MAMA PCR. The O1 and O139 serogroups were confirmed by O1rfb and O139 rfb genes in PCR. Both classical and El-Tor biotypes were observed in this one year round study. V. paraheamolyticus was confirmed by the presence of ToxRVP gene and all the strains were negative for tdh pathogenic gene by PCR. This study observed for the first time the seasonal pattern of V. parahaemolyticus in water bodies in Bangladesh showing a peak from February to April in all three sampling sites and another additional peak which span from August to September in Mirpur-1 Mazar pond, Dhaka, Bangladesh.

Study on Blood Pressure Changes in Postmenopausal Women

Menopause occupying one-third of women's life and women face various physiological, psychological and biochemical changes during this period. The systolic and diastolic blood pressure was significantly elevated among postmenopausal women as compared with reproductive women. To assess the blood pressure changes in healthy postmenopausal women in order to compare this parameter with healthy reproductive women, this analytical type of comparative study was carried out in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh from January 2017 to December 2017. Two hundred healthy women (100 female were postmenopausal as study group and 100 female were reproductive women as control group) aged between 25 to 65 years were enrolled in this study. Blood pressure of the individual was measured by an android sphygmomanometer and stethoscope with appropriate size of cuff. Data were expressed as mean±SD and statistical significance of difference among the group was calculated by unpaired students' 't' test. The mean±SD of systolic and diastolic blood pressure were higher in postmenopausal group in comparison to the reproductive women group. This study concludes systolic and diastolic blood pressure increases in postmenopausal women.

Relationship of HDL-C and Triglyceride with Hypertension in Adult Men

Hypertension is a complex disorder involving multiple organ systems and the primary modifiable risk factor for heart disease. Aim of the study was to assess the relationship of serum HDL-C and triglyceride with hypertensive patients in order to compare this parameter with normotensive subjects. This analytical type of cross sectional study was carried out in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2017 to June 2018. A total number of 120 male subjects, age ranged from 30-65 years was included in this study. Among them, sixty (60) hypertensive subjects were taken as study group (Group II) and sixty (60) ages matched normotensive male subjects were taken as control group (Group I). Data were expressed as mean±SD and statistical significance of difference among the group was calculated by unpaired student's 't' test. In this study we found that serum triglyceride and serum HDL cholesterol were significant in study group in comparison with control group. Therefore, by this study we recommended that routine estimation of these parameters is important for prevention of complication related to hypertension for leading a healthy life.

Relationship between HbA1c and Lipid Profile Seen in Bangladeshi Type 2 Diabetes Mellitus Patients Attending BIRDEM Hospital: A Cross-Sectional Study

Diabetes mellitus is one of the leading non-communicable diseases all over the world including Bangladesh. Diabetes is characterized by chronic hyperglycemia and disturbances of carbohydrate, lipid and protein metabolism. Glycated hemoglobin (HbA1c) level of ≥6.5% has been included as a criterion for diagnosis of diabetes. Impaired lipid profile is commonly present in type 2 diabetes. Aim of the study was to investigate the association between serum lipid profile and blood glucose. And hypothesizing that early detection of lipid abnormalities and treatment can minimize the risk for atherogenic cardiovascular disorder and cerebrovascular calamity in patients with type 2 diabetes mellitus (T2DM). This observational cross sectional study was carried out in the department of Biochemistry, Bangladesh Institute of Research & Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) hospital, Dhaka, Bangladesh from January 2016 to June 2016. A total 105 patients with T2DM of age within the range of 30-45 years were selected for the purpose. Fasting blood glucose (FBG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglyceride (TG) and glycated haemoglobin (HbA1c) levels were evaluated. Test of significance was calculated by unpaired Student's 't' test. Correlation studies (Pearson's correlation) were performed between glycated haemoglobin (HbA1c) and serum lipid profile. Significance was set at p<0.05. Significantly higher mean serum levels of TC, TG and LDL-C and significantly lower mean serum levels of HDL-C were noted in patients with diabetes. Significant correlations were observed between HbA1c value and serum levels of TC, TG and HDL-C (p<0.05) but no significant correlation of HbA1c value with LDL-C in-diabetes patient. The study concluded that HbA1c value correlate well with lipid profile in-diabetes patients. So, HbA1c can be used as a predictor of dyslipidemia in type 2 diabetes.

Comparative genomics of Vibrio cholerae O1 isolated from cholera patients in Bangladesh

Whole genome sequencing was utilized to investigate the genomic profile of Vibrio cholerae O1 strains, isolated from symptomatic patients in a low-income urban area of Dhaka, Bangladesh. Comparative genomics using bioinformatics tools were applied to identify major virulence factors, biotype and antimicrobial resistance genes in three V. cholerae O1 strains (VC-1, 2 and 3) isolated from two case patients. A phylogenetic SNP (single nucleotide polymorphism)-based analysis was conducted to infer the relatedness to V. cholerae O1 strains isolated elsewhere. The V. cholerae strains were the El Tor variant carrying ctxB1 (standard classical genotype). SNP-based global phylogeny revealed that the three isolates were strictly clonal and the closest neighbouring genomes were epidemic clones of V. cholerae O1 isolated in 2010 from cholera patients in Pakistan. All strains harboured the integrase gene of the SXT element (int_SXT ), antimicrobial resistance genes for aminoglycosides, phenicol, sulphonamide and trimethoprim except VC-1 that lacked sulphonamide resistance genes. The multilocus sequence typing (MLST) revealed that the strains belonged to sequence type, ST69. The study provides knowledge on current genetic traits of clinical V. cholerae O1 circulating in urban household clusters of Bangladesh which may help in predicting emergence of new pandemic strains in Bangladesh.

SIGNIFICANCE AND IMPACT OF THE STUDY

Vibrio cholerae has frequently experienced genetic changes with rapid evolution of pandemic clones in the Ganges Delta region. Whole genome sequencing can reveal genetic information of current pathogenic V. cholerae in Bangladesh which includes cefotaxime genotypes, virulence factors, altered antimicrobial resistance pattern as well as mobile genetic element compared to global pandemic strains. This study data could be used in planning future surveillance strategies in Ganges Delta region by informing new epidemiology of current outbreak strains.

Quantitative Analysis of Nucleic Acid Extraction Methods for Vibrio cholerae Using Real-time PCR and Conventional PCR

The devastating diarrheal disease cholera is caused by the bacterium Vibrio cholerae. Nucleic acid extraction is the primary step for several molecular detection approaches. In order to identify the sources of cholera illness, an efficient, fast and easy DNA extraction method for toxigenic Vibrio cholerae is desired which can be applied on diverse type of samples. This methodology developmental setup study was performed in the Environmental Microbiology Lab, Department of Microbiology, University of Dhaka, Bangladesh from March 2015 to May 2015 attempted to compare three DNA extraction methods for efficient detection and quantification of Vibrio cholerae. Three nucleic acid extraction methods: (Boiled template, Phenol: Chloroform: Isoamyl alcohol, QiaAmp® mini kit), were assessed for four, routinely tested, templates: crude culture, suspension in water, phosphate buffer saline (PBS), and food by conventional and real time PCR targeting the toxin-coding ctxA gene. Finally, the results were compared in context of processing time and overall cost. Cycle threshold (Ct) values were within acceptable parameters by real time PCR (5 to 35 cycles). All the three extraction methods produced sufficient yield of DNA and copy number for detection by real time and conventional PCR. The boiled template method for water samples yielded low amount of DNA in comparison to the other methods, and is therefore sensitive to detect by non-quantitative, conventional PCR only. Despite an overall low detectability from water samples, our comparison reveals that the boiled template method is the most suitable method for high quality and quantity pathogenic DNA particularly in light of limited access to expensive kits and reagents, time constraints, and high sample load.

Molecular characterization of extended spectrum βlactamase producing bacteria isolated from urinary tract infected patients, Bangladesh

The aims of the study were to examine the presence of extended spectrum βlactamase (ESBL) producing pathogen in urinary tract infected (UTI) patients and their respected molecular characterization and classification. The isolates collected from UTI patients attending a private hospital during the period between January and June, 2012, were biochemically identified and subjected to double disc synergy method for the detection of ESBL. ESBL genes were detected by multiplex PCR and antibiotic sensitivity test was performed. Thirty two percent of all Gram negative isolates were found as ESBL producer. Among 65 ESBL positive isolates, 77% were Escherichia coli, 20% Klebsiella pneumoniae and 3% were Pseudomonas spp. Around 48% isolates were found carrying at least one of the four ESBL genes, bla_CTX-M, bla_TEM, bla_SHV and bla_OXA, and were found in 32%, 23%, 18.5% and 3% of the isolates respectively. In antibiotic sensitivity assay, higher resistance was found in E. coli than K. pneumonia against ciprofloxacin and nalidixic acid. Interestingly, two E. coli and three K. pneumonia strains were found resistant to only 3^rd generation cephalosporines, but susceptible to all other antibiotics assessed. One E. coli strain was found resistant to ciprofloxacin but sensitive to nalidixic acid. Pseudomonas spp. was found resistant to most of the antibiotics. The susceptible rate to nitrofurantoin, amikacin, and gentamicin was also not satisfactory. Susceptibility (100%) to meropenem and imipenem render these as good alternatives to treat UTI. The majority of the isolates were positive for bla_CTX-M and adverted to molecular class A. Two strains carrying blaOXA gene along with bla_SHV/bla_TEM/bla_CTX-M, could not be included in any of the established ESBL classification.

Role of Serum Pepsinogen I and II Ratio in Screening of Gastric Carcinoma

In spite of the global decline in its incidence and mortality, gastric carcinoma still remains a major cause of death due to cancer. Early detection of gastric carcinoma is expected to reduce mortality rates. The applications of measuring of pepsinogen I and pepsinogen II are useful in screening of gastric carcinoma. This cross sectional comparative study was done to find out the correlation of histopathological pattern of gastric carcinoma with serum pepsinogen I & II ratio in the Department of Pathology, Sylhet MAG Osmani Medical College, Sylhet, Bangladesh from January 2010 to December 2010. For these purpose 40 patients with gastric carcinoma, endoscopically visible and histopathologically proved malignant lesions were enrolled as case group. Forty subjects with normal upper GI endoscopy were taken as control. Five ml of venous blood was taken from both case and control subjects to determine serum pepsinogen I and pepsinogen II level by ELISA method, subsequently pepsinogen I and II ratio was calculated. In this study different cut off values of serum pepsinogen I and II ratio was determined and the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 70.0%, 97.5% 96.6% 76.5% and 83.8% respectively, at cut off value of 6. Which is the most suitable cut off point of serum pepsinogen I and II ratio for gastric cancer screening.

Activation of tumor suppressor LKB1 by honokiol abrogates cancer stem-like phenotype in breast cancer via inhibition of oncogenic Stat3

Tumor suppressor and upstream master kinase Liver kinase B1 (LKB1) plays a significant role in suppressing cancer growth and metastatic progression. We show that low-LKB1 expression significantly correlates with poor survival outcome in breast cancer. In line with this observation, loss-of-LKB1 rendered breast cancer cells highly migratory and invasive, attaining cancer stem cell-like phenotype. Accordingly, LKB1-null breast cancer cells exhibited an increased ability to form mammospheres and elevated expression of pluripotency-factors (Oct4, Nanog and Sox2), properties also observed in spontaneous tumors in Lkb1^-/- mice. Conversely, LKB1-overexpression in LKB1-null cells abrogated invasion, migration and mammosphere-formation. Honokiol (HNK), a bioactive molecule from Magnolia grandiflora increased LKB1 expression, inhibited individual cell-motility and abrogated the stem-like phenotype of breast cancer cells by reducing the formation of mammosphere, expression of pluripotency-factors and aldehyde dehydrogenase activity. LKB1, and its substrate, AMP-dependent protein kinase (AMPK) are important for HNK-mediated inhibition of pluripotency factors since LKB1-silencing and AMPK-inhibition abrogated, while LKB1-overexpression and AMPK-activation potentiated HNK's effects. Mechanistic studies showed that HNK inhibited Stat3-phosphorylation/activation in an LKB1-dependent manner, preventing its recruitment to canonical binding-sites in the promoters of Nanog, Oct4 and Sox2. Thus, inhibition of the coactivation-function of Stat3 resulted in suppression of expression of pluripotency factors. Further, we showed that HNK inhibited breast tumorigenesis in mice in an LKB1-dependent manner. Molecular analyses of HNK-treated xenografts corroborated our in vitro mechanistic findings. Collectively, these results present the first in vitro and in vivo evidence to support crosstalk between LKB1, Stat3 and pluripotency factors in breast cancer and effective anticancer modulation of this axis with HNK treatment.

Orlistat (The Lipase Inhibitor) Therapy in Overweight and Obese Subfertile Women

This experimental study was carried out to evaluate the efficacy of orlistat (a pancreatic lipase inhibitor) therapy over lifestyle change on weight reduction and ovulation in overweight and obese subfertile women. It was carried out in Department of Gynecology and Obstetrics, Bangabandhu Sheikh Mujib Medical University (BSMMU) Dhaka, Bangladesh from August 2015 to January 2016. Subfertile obese and overweight female patients attending the study centre during study period was considered as study population. Subfertile women with normozoospermic husband with BMI (25-40) Kg/M2, age (18-35) years with no history of taking medication or dietary modification for weight loss currently or for the preceding 3 months were included in this study but subfertile patients having laparoscopic ovarian drilling and metformin and those with structural abnormalities in reproductive tract and known hormonal and medical disorder were excluded from this study. Detailed history taking, physical examination including weight, Body Mass Index (BMI) and baseline relevant investigations were done. Transvaginal sonography (TVS) on day 12 and day 14 of menstrual cycle was done for evaluation of ovulatory status of the patients. Counseling was done about life style change by diet of low glycemic index and moderate exercise. Following written informed consent, 120 patients were enrolled into either of the two groups. Group I received capsule Orlistat 120 mg twice daily for 3 months period. Group II was counseled for life style modification only. Post treatment weight measurement and TVS on day 12 and 14 were done after completion of intervention. Then pre and post-treatment parameters were assessed between two groups. Mean age was (27.31±4.58) years in Group I and (26.20±4.71) years in Group II. Majority patients, (78.3%) in Group I and (76.7%) in Group II had oligomenorrhoea. Hirsuitism was observed in (25%) in Group I and (43.3%) in Group II. Mean weight (kg) at booking was (72.26±7.81) in Group I and (67.10±5.93) in Group II; after 3 months (67.77±7.82) and (63.55±6.07). Reduction of weight (%): (6.52±2.28) in Group I and (5.33±2.14) in Group II which was significantly higher in Group I than that of Group II in (25.0-29.9) BMI. Ovulation assessed by TVS at booking and after 3 months in Group I: 13(21.7%) and 37 (61.7%) and in Group II: 14 (23.3%) and 27 (45.0%). Ovulation was higher in Group I than that of Group II, but the difference was not statistically significant. Majority of the overweight and obese subfertile patients suffered from oligomenorrhoea and anovulation. Weight significantly reduced in both groups along with ovulation improvement, more in Group I, but insignificant in between groups. Therefore this study suggested that orlistat can improve ovulation as it acts indirectly by weight reduction more than life style modification alone.

A Retrospective Histopathological Study on Extra-pulmonary Tuberculosis in Mymensingh

Tuberculosis is a very common disease in our country. This retrospective histopathological study was designed to assess the distribution of extra-pulmonary tuberculosis (EPTB) in various organs through examination of biopsy specimens. A total of 216 specimens were diagnosed as tubercular lesion by histopathological evaluation in the Department of pathology, Community Based Medical College and a private laboratory during the period from January 2014 to December 2014. Mean age of the case was 32 years. Majority of the cases were female (126 out of 216). Lymph nodes were the most common site of EPTB (62.96%) followed by skin and subcutaneous tissue (17.59%), intestine (11.11%), breast (2.77%), female genital tract (2.31%), male genital tract (1.38%), bone and joint (1.85%). Out of 136 cases of tubercular lymphadenitis, 96(70.58%) were cervical, 18(13.23%) were axillary, 12(3.82%) were mesenteric and 10(7.35%) were inguinal. This study reveals, in our locality, EPTB is very common in adulthood with female preponderance. Cervical lymph node is very common sites for EPTB.

Optimization and Validation of Real Time PCR Assays for Absolute Quantification of toxigenic Vibrio cholerae and Escherichia coli

Quantitative real-time PCR (qPCR) is a dynamic and cogent assay for the detection and quantification of specified nucleic acid sequences and is more accurate compared to both traditional culture based techniques and 'end point' conventional PCR. Serial dilution of bacterial cell culture provides information on colony forming unit (CFU) counts. This is crucial for obtaining optimal standard curves representative of DNA concentration. This approach eliminates variation in the standard curves caused by loss of DNA by serial dilution of nucleic acid elute. In this study, an assay was developed to detect and quantify DNA by real-time PCR for two pathogenic species, Escherichia coli (E. coli) and Vibrio cholerae (V. cholerae). In order to generate a standard curve, total bacterial DNA was diluted in a 10-fold series and each sample was adjusted to an estimated cell count. The starting bacterial DNA concentration was 11ng/µL. An individual E. coli cell has approximately 5.16 femtograms of DNA. Therefore, 11 ng/µL of DNA would indicate 2.48×10⁷cells. Both SYBR Green and TaqMan assays were validated for uidA region in E. coli and ctxA region in V. cholerae, respectively and was based on previously published assays for this standard curve experiment. PCR efficiency for uidA gene and ctxA gene were obtained 103.8% and 99.21%, respectively. Analysis of Variance (ANOVA) and coefficient of variation (CV %) indicated that standard curve generated by genomic DNA dilution had higher repeatability. Although not statistically significant, low F ratios indicated that there was some variation in CT values when genomic DNA dilution was compared to dilution of cell suspension in media. Different water samples spiked with pure cultures of E. coli and V. cholerae were used as unknown samples. The standard curve constructed by the serial dilution of genomic DNA exhibited greater efficiency when compared to that of the standard curve obtained from serial dilution of cell suspension since in the former method DNA is not lost during extraction from culture dilutions.

Effect of UV Irradiation on the Nutritional Quality and Cytotoxicity of Apple Juice

UV-C irradiation operating at 254 nm wavelength on the polyphenolic and vitamin contents of apple juice including cytotoxicity analysis was studied. UV doses ranging from 0 to 150 mJ·cm^-2 were selected for the treatments. Polyphenols (catechin, epicatechin, chlorogenic acid, and phloridzin) and vitamins (riboflavin, thiamine hydrochloride, pyridoxal hydrochloride, pyridoxine, pyridoxamine dihydrochloride, cyanocobalamin, choline chloride, biotin, niacin, and niacinamide) were chemically profiled. It was observed that UV treatment of apple juice at disinfection doses caused minor reductions (p < 0.05) in the concentrations of two main polyphenols (i.e., chlorogenic acid and epicatechin). In contrast, significant (p < 0.05) decreases in vitamin concentrations were observed (p < 0.05). The irradiated juice was evaluated for cytotoxic effects. The irradiated apple juice showed no cytotoxic effects on normal intestinal cells, and both irradiated and nonirradiated samples are significantly comparable in inhibiting the growth of human colon cancer cells. Overall, these results indicated that UV-C treatment of apple juice neither significantly degraded polyphenols nor generated cytotoxic compounds.

Challenges in HbA1C Level as a Diagnostic Tool of Diabetes and Pre-Diabetes in Middle-Aged Population: The Bangladesh Study

Worldwide prevalence of diabetes is found to be the human health at an alarming rate. However, large numbers of patient remain undiagnosed. Oral glucose tolerance test (OGTT) still is regarded as gold standard in diagnosis of blood glucose abnormality. Although the less number of bodies are considering measurement of HbA1C as an alternate tool to identify risk group. This study was undertaken to evaluate the role of measurement of HbA1C in the diagnosis of diabetes and pre-diabetes in middle-aged Bangladeshi subjects and carried out in the department of Biochemistry, BIRDEM from July 2013 to June 2014. A total 177 subjects of age within the range of 30-45 years were selected for the purpose and classified into healthy control (n=62) pre-diabetes (n=69) and diabetes (n=46) groups based on the values of OGTT. Middle aged Bangladeshi subjects attending Bangladesh Institute of Research & Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) hospital, the HbA1C values were 5.0-5.6% in control group, 5.6-6.2% in pre-diabetes and 8.1-9.7% in diabetes group (95% CI). The optimal cut-off value of HbA1C related to pre-diabetes diagnosed by OGTT was 5.6%, which showed the sensitivity 47.8%, specificity 74.2%, positive predictive value 67.3% and negative predictive value 58.5%. Variants of hemoglobin especially Hemoglobin E (HbE) is prevalent in South East Asia including Bangladesh. The presence of genetic variants of hemoglobin can profoundly affect the accuracy of HbA1C measurements. So measurement of HbA1C may not be used as an alternate tool of OGTT to identify people of diabetes and pre-diabetes in certain situation.

Spectrum of Salivary Gland Lesions in a Tertiary Level Hospital

Salivary gland tumors are relatively infrequent and account for less than 2% of all human tumors. This study was conducted to see the prevalence of patterns of non neoplastic and neoplastic lesions of salivary glands in greater Mymensingh. It was a retrospective study carried out in the department of Pathology, Community Based Medical College Bangladesh from January 2010 to December 2012. Heamatoxylin and eosin stained sections were studied in all cases. Total 98 cases of salivary gland lesions were retrieved and evaluated. Out of them 55 cases were female and 43 were male. Mean age of the cases were 42 years. Among the salivary gland lesions non-neoplastic lesions 24.48% and neoplastic lesions 75.51%. Among neoplastic lesions benign tumor comprises 91.89% and malignant tumor comprises 8.10%.

Relation of maternal vitamin D status with gestational diabetes mellitus and perinatal outcome

OBJECTIVE

To investigate the relationship between maternal vitamin D status and glucose intolerance, and its impact on pregnant women and their newborns.

METHODS

A cohort of pregnant women were divided into three groups: women with gestational diabetes mellitus, ones with normal results both after the 50 gr and 100 gr OGTT (CG-1) and ones having a positive result after the 50 gr OGTT screening but negative results for gestational diabetes mellitus (GDM) after the 100 gr OGTT (CG-2).

RESULTS

The newborn length in CG-1 was greater than in GDM and CG-2 (p= 0.002 and p= 0.02). Fasting blood glucose and insulin resistance (IR) were negatively correlated with length of the newborns (r=-0.3, p=0.03 and r=-0.3, p=0.01). The newborns of women with GDM had lower APGAR-1 and 5 scores than those of CG-1 and CG-2 (APGAR-1 p= 0.001 and p= 0.004, APGAR-5 p=0.005 and p=0.007, respectively). APGAR scores were correlated negatively with IR (APGAR-1 r=-0.32, p=0.01, APGAR-5 r=-0.3, p=0.03) and positively with 25OHD levels (APGAR-1 r=0.3, p=0.01, APGAR-5 r=0.3, p=0.02).

CONCLUSION

Vitamin D deficiency, gestational diabetes and insulin resistance are interrelated. Severe vitamin D deficiency during pregnancy is associated with poor pregnancy and neonatal outcome.

Subjective cognitive complaints across the adult life span: a 14-year analysis of trends and associations using the 1993, 2000 and 2007 English Psychiatric Morbidity Surveys

BACKGROUND

Cognitive complaints are common in all age groups but most often researched in old age. We aimed to investigate prevalences and time trends over 14 years of subjective memory complaints (SMC) and subjective concentration complaints (SCC) in adults and investigate associations with mood disorders and cognitive function.

METHOD

Data from three English national mental health surveys carried out in 1993, 2000 and 2007 were analysed. SMC and SCC were measured using the Clinical Interview Schedule-Revised and cognitive function using the modified Telephone Interview for Cognitive Status.

RESULTS

Both SMC and SCC increased up to middle age and then declined, followed by a second rise in the very oldest age groups. Age-specific prevalence of both increased across survey years but relationships with mental health and cognitive outcomes were relatively stable.

CONCLUSIONS

Cognitive complaints are most common in middle age and have become more prevalent over time.

Vaginal rhinosporidiosis: a case report

The female genital tract is an extremely rare site for Rhinosporidiosis. Here we described a 13 year old girl who presented with a slow growing polypoid fleshy mass in the posterior vaginal wall near the orifice for 6 months with scanty bleeding from the mass. The girl was admitted to hospital with profuse watery vaginal discharge. Excision of the mass was followed by histopathological examination which confirmed the diagnosis Rhinosporidiosis.

Long versus standard initial prednisolone therapy in children with idiopathic nephrotic syndrome

The efficacy of longer initial course of prednisolone with standard regimen was compared in children with idiopathic nephrotic syndrome (INS). It was a randomized controlled trial in which patients with INS who responded to initial course of prednisolone, either long or standard regimen were included and followed for one year after completion of treatment of first attack. The long regimen consisted of prednisolone 60mg/m²/day for six weeks followed by 40mg/m² every alternate day single morning dose for further six weeks. The standard regimen consisted of prednisolone 60mg/m²/day for four weeks followed by 40mg/m² every alternate day single morning dose for further four weeks. There were 93 children who fulfilled the criteria of the study, 47 from long group and 46 from standard group though ultimately 72 completed the study (41 from long and 31 from standard group). The primary outcome measure was relapse within next one year. Relapse within one year was noted in 73.2% of long and 64.5% of standard group. The odds ratio for relapse within one year was 0.80 (95% confidence interval 0.22, 2.05). This did not reach statistical significance (p=0.696). Adverse effects of prednisolone between two groups were also not statistically significant (p>0.05). Prolongation of prednisolone therapy for initial episode of steroid-sensitive INS does not have a beneficial effect on the outcome in next one year.

Gastrointestinal helminths in pigeon Columba livia (Gmelin, 1789)

A total of 60 pigeon, Columba livia (25 males and 35 females) were examined to observe helminth parasite infection. All the birds were found to be infected by eleven species of helminth parasites: four species of trematoda: Echinostoma revolutum (15%) E. trivolvus (5%), Patagifer bilobus (5%), Ehinoparyphium recurvatum (8.33%); six species of cestoda: Hymenolepis columbae (63.33%), Raillietina echinobothrida (100%), R. bonini (43.33%), R. cesticillus (100%), Cotugnia celebesensis (68.33%), C. cuneata (100%); and one species of nematoda: Ascaridia columbae (28.33%). Females showed slightly higher intensity of infestation than the males. Trematode parasites were found in intestine and rectum, cestode parasites were found in duodenum and intestine, nematode parasite Ascaridia columbae was found in caeca. Oesophagus, crop, proventriculus, gizzard, gallbladder, liver, kidney and muscles were free of parasites. Considering among seasons highest intensity of infection was found in autumn. DOI: http://dx.doi.org/10.3329/jasbs.v38i1.15324 J. Asiat. Soc. Bangladesh, Sci. 38(1): 93-98, June 2012

Guillain-Barre Syndrome Following Dengue Fever in Adult Patient

Guillain-Barre syndrome is a post infectious ascending, usually demyelinationg polyradiculoneuropathy. Dengue fever as an antecedent infection in GBS is uncommon. A 39-year-old female presented with acute flaccid weakness of both upper and lower limbs which developed in ascending and progressive fashion following a febrile illness of three days. During work-up IgM for dengue virus was found positive. Diagnosis of Guillain-Barre syndrome was made based on neurologic manifestations, the typical CSF findings and pattern of electrophysiological study and exclusion of other pathologies. Patient was treated with intravenous immunoglobulins. During the course of illness, she developed lower motor neuron type trigeminal, facial, glossopharyngeal, vagus and hypoglossal nerve palsy and autonomic involvement. She had significant recovery and was able to talk, eat and walk six weeks later. Dengue is endemic in Bangladesh. Post dengue Guillain- Barre syndrome in adult, as shown in previous reports, should now be considered in the part of spectrum of neurological complications of this infection. DOI: http://dx.doi.org/10.3329/jom.v13i2.12772 J Medicine 2012; 13 : 246-249

A case of battered wife

The use of corrective force against the wife is still rife in all cultures and even socially acceptable in some culture. Domestic violence is still common in our society. We report a case of 20 years old woman who admitted into OCC of DMCH through emergency department owing to be assaulted by her husband. This case is exceptional one because the injuries inflicted upon her were over the middle of the forehead and clean cut in nature, though non fatal. Awareness and education is needed to stop this social stigma DOI: http://dx.doi.org/10.3329/bjms.v11i3.11736 Bangladesh Journal of Medical Science Vol. 11 No. 03 July’12

De novo chromosomal translocation t(3;5)(q13;q35) in an infertile man

Chromosomal rearrangements are rare structural abnormalities that are usually associated with male infertility or sterility. We describe here the clinical and cytogenetic studies carried out in a couple with repeated abortions. Cytogenetic analysis of the male partner showed a de novo chromosomal translocation t(3;5)(q13;q35) which could be involved in the meiotic errors resulting in reproductive failure.

Histological variant of nephrotic syndrome with atypical presentation in children

Aims of the present study were to find out the histological pattern of atypically presenting nephrotic syndrome children and their response with oral corticosteroid therapy. This prospective study was carried out in the Paediatric Nephrology unit of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, for a period of two years, from September 2001 to September 2003. Forty children with nephrotic syndrome with atypical presentations such as gross haematuria, renal impairment, hypertension and hypocomplementaemia were enrolled for the study. For each patient proper investigations were done to screen out infection and necessary treatment was given accordingly. Renal biopsy was done in all cases after treating infection and controlling hypertension and specimen were evaluated by light and immunofluorescence microscopy. All the patients were treated with oral prenisolone 60 mg/m2/day for 4 weeks and response were observed by heat coagulation test. In present study it was observed that mean age of presentation was 8.73+/-4.36 years. Hypertension, gross haematuria, impaired renal function and hypo-complementaemia were observed in 50%, 45%, 19% and 15% cases respectively. When histopathologies were considered, 90% cases had other than minimal change disease (MCD) and Mesangial proliferative glomerulonephritis (MesPGN) was the most common histopathology (47.5%). Regarding steroid therapy only 43.2% patients were responsive to oral prednisolone therapy within 28 days. Atypically presented nephrotic syndrome usually manifested with higher age of onset, gross haematuria, hypertension, renal insufficiency and hypocomplementaemia. Mesangial proliferative glomerulonephritis was the predominant histological type. The majority (56.8%) of these atypically presented nephrotic syndromes were resistant to steroid therapy.

Comparison between DOT EIA IgM and Widal Test as early diagnosis of typhoid fever

A recently developed DOT enzyme immunoassay known as "Typhidot" for detecting IgM antibody against 50 KDa OMP antigen of Salmonella typhi, was evaluated on 100 clinically suspected typhoid fever cases and 40 age-sex matched controls, in the Department of Microbiology, Mymensingh Medical College during, the period from June 2006 to July 2007. Blood culture, Widal test, and DOT EIA for IgM test were performed in all patients. Among 100 clinically suspected typhoid fever cases, 35 were subsequently confirmed on the basis of positive blood culture for S. typhi and/or significant rising titre of Widal test. The DOT EIA IgM test could produce results within 1 hour. The result of the DOT EIA IgM test showed a good diagnostic value for typhoid fever. The sensitivity, specificity, positive and negative predictive value of the test was found as 91.42%, 90.00%, 88.88% and 92.30% respectively. On the other hand corresponding values for Widal test were of 42.85%, 85.00%, 71.42% and 62.96% respectively. Thus, The DOT EIA IgM seems to be a practical alternative to Widal test for early diagnosis of typhoid fever.

A case of renal transplantation

A 12-year-old boy was admitted in paediatric nephrology unit of Bangabandhu Sheikh Mujib Medical University (BSMMU) with massive proteinuria, hypertension, respiratory distress and anaemia and diagnosed as nephrotic syndrome. Percutaneous needle biopsy was consistent with diffuse endocapillary proliferative glomerulonephritis and initially managed conservatively with injection methyl prednisolone, cyclophosphamide, lisinopril etc. without any improvement. Living-related renal transplantation was done successfully from paternal uncle. Two episodes of acute rejection occurred, one immediately after transplantation and another after one month. These were managed with IV methyl prednisolone for 3 days. At present, he is on oral prednisolone, cyclosporine, azathioprine and antihypertensives with normal haemoglobin and stable serum creatinine level (pre-transplant level 12.5mg/dl to post-transplant level 1.5mg/dl). He has been maintaining his normal life including schooling for last few months. It is concluded that a patient with uncommon presentation of nephrotic syndrome should be confirmed by renal biopsy and renal transplantation may be considered if conservative measures fail.

Urinary tract infection and vesicoureteric reflux in children

A retrospective study of 74 children with Urinary Tract Infection (UTI) were evaluated for the prevalence of vesicoureteric reflux (VUR) at a tertiary hospital in Dhaka, Bangladesh from 2003 to 2006. There were 45 (60%) girls and 29 (40%) boys; 58 (78%) were at an average age between 1-5 years, 11 (15%) were between 0-1 year and five (7%) were more than 5 years of age. All patients were documented to have UTI by history and laboratory investigations. There were 27 (36%) patients who had acute pyelonephritis at the initial clinical presentation and fourty seven (64%) patients had recurrent UTI. Thirty two (43%) patients had vesicoureteric reflux; fifteen (47%) had it bilaterally (VUR); and 13 (41%) had renal scarring. Five (7%) patients who had renal scarring were with- out reflux. Twenty three (72%) of the VUR patients had mild to moderate reflux (grade 1-3) and nine (28%) had severe reflux (grade 4-5). The age of the patients with VUR was below one year in 13 (40%), between 1 and 5 years in 17 (53%) and between 6 and 12 years 2 (7%) patients. There were 9 (33%) patients with acute pyelonephritis who had reflux. Follow-up of the VUR patients showed that reflux disappeared with out surgical intervention in 14 (44%), improved in three (9%) to lower grade and worsened in two (6%) to higher grade. Five (16%) patients underwent ureteral re-implantation; all the patient of VUR had recurrent UTI and were more than one year of age. While on chemoprophylaxis, two of the reimplanted patients developed break-through UTI. None of the study patients developed new scars, hypertension or renal failure during follow-up; the duration of follow-up was from 6 months to 3 years. Children with UTI below 6 years of age have high incidence of reflux and scarring with specially in patients with acute pyelonephritis.

Congenital nephrotic syndrome, an uncommon presentation of cytomegalovirus infection

Cytomegalovirus (CMV) infection is a very rare infection in children as well as in infancy. In CMV infection extra renal manifestations in central nervous system (CNS), eyes and hematological are prominent and common than renal manifestation. We are describing two case reports one at the age of 5 months and another at one month with features of both extra renal and renal manifestations of nephritic syndrome. Our first case presented with predominant features of CNS manifestations like convulsion and spastic monoplegia, sensory type of deafness and absence of light reflexes along with nephritic features. Deafness and absence of light reflex were confirmed by audiometric and ophthalmological examination and brain atrophy was confirmed by CT scan. Our second case had features of hypothyroidism along with nephritic features. Hypothyroid status was confirmed by elevated serum TSH level and reduced T4 level. In both cases nephritic features were confirmed at bed site urine examination by heat coagulation test and other relevant investigations. CMV infection was confirmed in both cases by detecting anti CMV IgM by ELISA method. Both patients were clinically improved with intravenous gangcyclovir therapy. In these two cases reports, clinical, serological and therapeutic observation established the causal relationship between the CMV infection and nephrotic syndrome.

Corrections to air kerma and exposure measured with free air ionisation chambers for charge of photoelectrons, Compton electrons and Auger electrons

The signal charge from a free air ionisation chamber for the measurement of air kerma and exposure consists of not only the charge of ion pairs produced by secondary electrons (i.e. photoelectrons, Compton electrons and Auger electrons), but also the charge of the secondary electrons and single and multiple charged ions formed by the release of the secondary electrons. In the present work, correction factors for air kerma and exposure for the charge of the secondary electrons and ions were calculated for photons with energies in the range from 1 to 400 keV. The effects of an increase in the W value of air for low-energy electrons were also taken into consideration. It was found that the correction factors for air kerma and exposure have a maximum value near a photon energy of 30 keV; in the lower energy region, the correction factor for exposure monotonically decreases with a decrease in photon energy except for a small dip due to K-edge absorption by argon atoms in air. The values of the correction factors were found to be 0.9951 and 0.9892, respectively, for a spectrum with a mean energy of 7.5 keV, the reference X-ray spectrum with the lowest mean energy in ISO 4037-1. The air kerma correction is smaller than that for exposure, because for air kerma the signal due to the charge of secondary electrons and ions is partly compensated by the decrease in the number of ion pairs produced by the secondary electrons due to the increase of the W value of air for lower energy electrons.