Probabilistic exposure assessment, a risk-based sampling plan and food safety performance evaluation of common vegetables (tomato and brinjal) in Bangladesh

Mohammad Nurun-Nabi Mazumder,Aung Bo Bo,Seung Chul Shin,Liesbeth Jacxsens,Tahmina Akter,Md. Shahidul Haque Bir,Most Mohshina Aktar,Md. Habibur Rahman,Jia WeiQiang,Kee Woong Park 충남대학교 농업과학연구소 2021 Korean Journal of Agricultural Science Vol.48 No.1

Polymorphonuclear Neutrophil Dysfunctions in Streptozotocin-induced Type 1 Diabetic Rats

Nabi, A.H.M. Nurun,Islam, Laila N.,Rahman, Mohanmmad Mahfuzur,Biswas, Kazal Boron Korean Society for Biochemistry and Molecular Biol 2005 Journal of biochemistry and molecular biology Vol.38 No.6

Since conflicting results have been reported on non-specific immune response in type 1 diabetes, this study evaluates polymorphonuclear neutrophil (PMN) functions in the infection free Long Evan diabetic rats (type 1) by using tests that include: polarization assay, phagocytosis of baker's yeasts (Saccharomyces cerevisiae) and nitroblue tetrazolium (NBT) dye reduction. Polarization assay showed that neutrophils from diabetic rats were significantly activated at the basal level compared to those from the controls (p < 0.001). After PMN activation with N-formyl-methionyl-leucyl-phenylalanine (FMLP), control neutrophils were found to be more polarized than those of the diabetic neutrophils and the highest proportions of polarization were found to be 67% and 57% at $10^{-7}\;M$ FMLP, respectively. In the resting state, neutrophils from the diabetic rats reduced significantly more NBT dye than that of the controls (p < 0.001). The percentages of phagocytosis of opsonized yeast cells by the neutrophils from control and diabetic rats were 87% and 61%, respectively and the difference was statistically significant (p < 0.001). Evaluation of the phagocytic efficiency of PMNs revealed that control neutrophils could phagocytose $381{\pm}17$ whereas those from the diabetic rats phagocytosed $282{\pm}16$ yeast cells, and the efficiency of phagocytosis varied significantly (p < 0.001). Further, both the percentages of phagocytosis and the efficiency of phagocytosis by the diabetic neutrophils were inversely related with the levels of their corresponding plasma glucose (p = 0.02; r = -0.498 and p < 0.05; r = -0.43, respectively), which indicated that increased plasma glucose reduced the phagocytic ability of neutrophils. Such relationship was not observed with the control neutrophils. These data clearly indicate that PMN functions are altered in the streptozotocin (STZ) - induced diabetic rats, and hyperglycemia may be the cause for the impairment of their functions leading to many infectious episodes.

Polymorphonuclear Neutrophil Dysfunctions in Streptozotocin-induced type 1 Diabetic rats

A. H. M. Nurun Nabi,Laila N. Islam,Mohammad Mahfuzur Rahman,Kazal Boron Biswas 한국생활환경학회 2005 BMB Reports Vol.38 No.6

Comparison between Visual Inspection of Cervix and Cytology Based Screening Procedures in Bangladesh

Nessa, Ashrafun,Nahar, Khadiza Nurun,Begum, Shirin Akhter,Anwary, Shahin Ara,Hossain, Fawzia,Nahar, Khairun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background: Cervical cancer continues to be a major problem in Bangladesh with approximately 18,000 new cases annually of which over 10,000 women die from it. Visual inspection of the cervix after 3-5% acetic acid (VIA) application is a simple and easy to learn method for cervical cancer screening, although cytology-based screening is more often applied in developed countries where it has successfully reduced the prevalence of cervical cancer. Objective: To compare the efficacy of VIA and cytology-based primary methods for cervical cancer screening in Bangladesh. Materials and Methods: This hospital based comparative study was conducted at the VIA centre and Colposcopy Clinic of Bangabandhu Sheikh Mujib Medical University (BSMMU) from October 2008 to October 2010. Results: Among 650 women, 74 (11.4%) were VIA+ve and 8 (1.2%) had abnormalities in their Pap smear reports. During colposcopy, 38 (7.7%) women had different grades of CIN and 4 (0.6%) had cervical cancer. The gold standard histology findings proved 20 women had CIN I, 14 had CIN II/II and 4 had cervical cancer. Among the 38 histology diagnosed abnormalities, VIA test could identify 30 abnormalities including two cervical cancers. However, Pap smear could detect only 8 cases of histological abnormalities (2 low grade and 6 had high grade lesion) and it missed all the cervical cancer cases. The sensitivity and specificity of VIA were 88.9% and 52.1%. The positive predictive value (PPV) and negative predictive value (NPV) were 41.0%, and 92.6% respectively. Moreover, the sensitivity, specificity, PPV and NPV of Pap smear were 33.3%, 95.8%, 75.0% and 79.3%, respectively. Conclusions: VIA test should be used as the primary screening tool even with its low sensitivity and specificity in low resource countries like Bangladesh. False positive results may be greater, but overtreatment can be minimized by colposcopy evaluation of the VIA positive women.

Endotoxins of Enteric Pathogens Modulate the Functions of Human Neutrophils and Lymphocytes

( Laila N. Islam ),( A. H. M. Nurun Nabi ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.6

The locomotor responses of human peripheral blood neutrophils and lymphocytes were measured by the change from spherical to polarized shapes in the presence of endotoxins (lipopolysaccharide, LPS) of enteric pathogens: S. dysenteriue type 1, V.cholerae Inaba 569B, S. typhimurium, and K. pneumoniae. We reported earlier that these endotoxins are chemotactic factors for the neutrophils since they stimulated cell polarization within a few minutes of incubation. Endotoxins had an inhibitory effect upon neutrophil phagocytosis of opsonized yeast and the cells engulfed fewer yeasts. Interestingly, endotoxins increased neutrophil adhesion to clean glass surfaces, but stimulated the cells to exhibit increased random locomotion (chemokinesis) through cellulose nitrate filters and show an enhanced ability to reduce nitroblue tetrazolium (NBT) dye. Unlike neutrophils, lymphocytes direct from blood do not show polarized morphology towards chemotactic factors but the cells acquire locomotor capacity during 24-72 h culture with mitogens uch as phytohemagglutinin (PHA), phorbol myristate acetate or concanavalin A. Stimulation of blood lymphocytes with endotoxins did not induce cell polarization in short-term but long-term culture resulted in an increase in the proportion of polarized cells that acquired locomotor morphologies. The majority of these cells were identified as esterase negative B-lymphocytes that migrated through filters. Despite the optimum time of incubation for each of these cell types being different, we found that lymphocytes respond to much lower concentrations of endotoxins than the neutrophils. These findings suggest that endotoxins of enteric pathogens modulate the functions of human blood neutrophils and lymphocytes.

Endotoxins of Enteric Pathogens Are Chemotactic Factors for Human Neutrophils

(Laila N. Islam),(A. H. M. Nurun Nabi),(K. Mokim Ahmed),(Novera Sultana) 생화학분자생물학회 2002 BMB Reports Vol.35 No.5

Early activation of human peripheral blood polymorphonudear neutrophils is characterized by their morphological changes from spherical to polarized shapes. The endotoxins from enteric pathogens (S. dysenteriae type 1, V cholerae Inaba 569B, S. typhimurium, and K. pneumoniae) were assessed by their ability to induce morphological polarization of the neutrophils as measures of early activation. Phagocytic activity, adhesion, chemokinetic locomotion, and nitroblue tetrazolium (NBT) dyereduction ability measured the later activation of the cells. Neutrophils showed distinct morphological polarization in suspension over a wide range of concentrations of these endotoxins when were compared with those that were induced by the standard chemotactic factor, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It was discovered that all of the endotoxins induced locomotor responses in neutrophils in suspension that were dose- and time-dependent. The optimum concentration for the endotoxins of S. dysenteriae, V. cholerae, and K pneumoniae was 1 mg/ml in which 71, 69, and 66% of the neutrophils were polarized. However, the S. typhimurium dose was 2 mg/ml in which 50% of the cells responded. Neutrophils that were stimulated with endotoxins also showed increased random locomotion (p<0.005) through cellulose nitrate filters, but an enhanced adhesion of the cells to glass surfaces (p<0.03). These are important functions of these cells to reach and phagocytose damaged cells, as well as invading microorganisms. Interestingly, the endotoxins had a highly-significant inhibitory effect upon the proportions of neutrophils phagocytosing opsonized yeast (p<0.01) with a small number of yeast that were engulfed by the cells (p<0.02). Further, endotoxin-treated cells showed an enhanced ability to reduce NBT dye (p<0.03). Therefore, we concluded that endotoxins of enteric pathogens are neutrophil chemotactic factors.

Endotoxins of Enteric Pathogens Modulate the Functions of Human Neutrophils and Lymphocytes

Islam, Laila N.,Nabi, A.H.M. Nurun Korean Society for Biochemistry and Molecular Biol 2003 Journal of biochemistry and molecular biology Vol.36 No.6

The locomotor responses of human peripheral blood neutrophils and lymphocytes were measured by the change from spherical to polarized shapes in the presence of endotoxins (lipopolysaccharide, LPS) of enteric pathogens: S. dysenteriae type 1, V. cholerae Inaba 569B, S. typhimurium, and K. pneumoniae. We reported earlier that these endotoxins are chemotactic factors for the neutrophils since they stimulated cell polarization within a few minutes of incubation. Endotoxins had an inhibitory effect upon neutrophil phagocytosis of opsonized yeast and the cells engulfed fewer yeasts. Interestingly, endotoxins increased neutrophil adhesion to clean glass surfaces, but stimulated the cells to exhibit increased random locomotion (chemokinesis) through cellulose nitrate filters and show an enhanced ability to reduce nitroblue tetrazolium (NBT) dye. Unlike neutrophils, lymphocytes direct from blood do not show polarized morphology towards chemotactic factors but the cells acquire locomotor capacity during 24-72 h culture with mitogens such as phytohemagglutinin (PHA), phorbol myristate acetate or concanavalin A. Stimulation of blood lymphocytes with endotoxins did not induce cell polarization in short-term but long-term culture resulted in an increase in the proportion of polarized cells that acquired locomotor morphologies. The majority of these cells were identified as esterase negative B-lymphocytes that migrated through filters. Despite the optimum time of incubation for each of these cell types being different, we found that lymphocytes respond to much lower concentrations of endotoxins than the neutrophils. These findings suggest that endotoxins of enteric pathogens modulate the functions of human blood neutrophils and lymphocytes.

Endotoxins of Enteric Pathogens Are Chemotactic Factors for Human Neutrophils

Islam, Laila N.,Nabi, A.H.M. Nurun,Ahmed, K. Mokim,Sultana, Novera Korean Society for Biochemistry and Molecular Biol 2002 Journal of biochemistry and molecular biology Vol.35 No.5

Early activation of human peripheral blood polymorphonuclear neutrophils is characterized by their morphological changes from spherical to polarized shapes. The endotoxins from enteric pathogens (S. dysenteriae type 1, V. cholerae Inaba 569B, S. typhimurium, and K. pneumoniae) were assessed by their ability to induce morphological polarization of the neutrophils as measures of early activation. Phagocytic activity, adhesion, chemokinetic locomotion, and nitroblue tetrazolium (NBT) dye-reduction ability measured the later activation of the cells. Neutrophils showed distinct morphological polarization in suspension over a wide range of concentrations of these endotoxins when were compared with those that were induced by the standard chemotactic factor, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It was discovered that all of the endotoxins induced locomotor responses in neutrophils in suspension that were dose- and time-dependent. The optimum concentration for the endotoxins of S. dysenteriae, V. cholerae, and K. pneumoniae was 1 mg/ml in which 71, 69, and 66% of the neutrophils were polarized. However, the S. typhimurium dose was 2 mg/ml in which 50% of the cells responded. Neutrophils that were stimulated with endotoxins also showed increased random locomotion (p<0.005) through cellulose nitrate filters, but an enhanced adhesion of the cells to glass surfaces (p<0.03). These are important functions of these cells to reach and phagocytose damaged cells, as well as invading microorganisms. Interestingly, the endotoxins had a highly-significant inhibitory effect upon the proportions of neutrophils phagocytosing opsonized yeast (p<0.01) with a small number of yeast that were engulfed by the cells (p<0.02). Further, endotoxin-treated cells showed an enhanced ability to reduce NBT dye (p<0.03). Therefore, we concluded that endotoxins of enteric pathogens are neutrophil chemotactic factors.

Polymorphonuclear Neutrophil Dysfunctions inStreptozotocin-induced Type 1 Diabetic Rats

Mohammad Mahfuzur Rahman,Laila N. Islam,Kazal Boron Biswas,A.H.M. Nurun Nabi 한국생화학분자생물학회 2005 BMB Reports Vol.38 No.6

Sources of Carbonaceous Materials in the Airborne Particulate Matter of Dhaka

Bilkis A. Begum,Philip K. Hopke,Anwar Hossain,Golam Saroar,Swapan K. Biswas,Md. Nasiruddin,Nurun Nahar,Zohir Chowdury 한국대기환경학회 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.4

To explore the sources of carbonaceous material in the airborne particulate matter (PM), comprehensive PM sampling was performed (3 to 14 January 2010)at a traffic hot spot site (HS), Farm Gate, Dhaka using several samplers: AirMetrics MiniVol (for PM_10and PM_2.5) and MOUDI (for size fractionated submicron PM). Long-term PM data (April 2000 to March 2006 and April 2000 to March 2010 in two size fractions (PM2.2 and PM_2.2-10) obtained from two air quality-monitoring stations, one at Farm Gate (HS) and another at a semi-residential (SR) area (Atomic Energy Centre, Dhaka Campus, (AECD)), respectively were also analyzed. The long-term PM trend shows that fine particulate matter concentrations have decreased over time as a result of government policy interventions even with increasing vehicles on the road. The ratio of PM_2.5/PM_10 showed that the average PM_2.5 mass was about 78% of the PM10 mass. It was also found that about 63% of PM_2.5 mass is PM_1. The total contribution of BC to PM_2.5 is about 16%and showed a decreasing trend over the years. It was observed that PM_1 fractions contained the major amount of carbonaceous materials, which mainly originated from high temperature combustion process in the PM_2.5. From the IMPROVE TOR protocol carbon fraction analysis, it was observed that emissions from gasoline vehicles contributed to PM_1 given the high abundance of EC1 and OC2 and the contribution of diesel to PM_1 is minimal as indicated by the low abundance of OC1 and EC2. Source apportionment results also show that vehicular exhaust is the largest contributors to PM in Dhaka. There is also transported PM_2.2 from regional sources. With the increasing economic activities and recent GDP growth,the number of vehicles and brick kilns has significantly increased in and around Dhaka. Further action will be required to further reduce PM-related air pollution in Dhaka.