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Anderson JA, Jana M, Dasgupta S, Liu X, Pahan K. Involvement of P38MAP kinase in the induction of nitric oxide synthase in human astrocytes. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.18_3.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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102
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Auch CJ, Dasgupta S, Jana M, Liu X, Pahan K. Double-stranded RNA induces nitric oxide synthase in human astrocytes. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.18_5.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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103
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Dasgupta S, Jana M, Liu X, Pahan K. Induction of nitric oxide synthase in microglial cells by MBP-primed T cells. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.18_2.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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104
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Dasgupta S, Zhou Y, Jana M, Pahan K. Poster Sessions BP05: Neuroimmunology. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.18_1.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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105
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Pahan K, Jana M, Dasgupta S, Liu X. Induction of nitric oxide synthase in cytokine-stimulated human astrocytes by interleukin-12 P40 monomer. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.18_4.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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106
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Jana M, Dasgupta S, Liu X, Pahan K. Interleukin-12 P40 induces the expression of TNF-α in microglia and macrophages. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.17_1.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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107
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Dasgupta S, Pandey BK, Sarangi N, Mukhopadhyay PK. Evaluation of water productivity and fish yield in sewage-fed vis-à-vis fertilized based carp culture. BIORESOURCE TECHNOLOGY 2008; 99:3499-506. [PMID: 17881225 DOI: 10.1016/j.biortech.2007.07.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 07/28/2007] [Accepted: 07/30/2007] [Indexed: 05/17/2023]
Abstract
Reuse of wastewater in aquaculture provides a scope to enhance water productivity of the system. Quantification of nutrient inputs incorporated through treated domestic sewage with varying dosages viz. 79.3 x 10(5)lha(-1) and 67.7 x 10(5)lha(-1) and water productivity in a controlled carp culture system were assessed in comparison to those involved in a fertilized based one, with a view to correlate among physical, chemical and biological processes involved in fish yield under the systems. The net water productivities were measured on the basis of net return values (in Indian rupees; INR) from the carp production systems at a stocking density @ 5000 per ha with four species combination. Selected relevant water parameters such as dissolved oxygen, total alkalinity, biochemical oxygen demand (BOD5) in sewage effluent and fertilizer based systems were monitored along with certain biological parameters viz. gross primary productivity, fish production and water productivity. The nutrient inputs in terms of total ammonia-nitrogen (TAN) in effluents, total nitrogen (TN) in fertilizers and phosphorus (P2O5) in both effluents and fertilizers were found significantly correlated with biological production. The results of the experiment revealed that the sewage incorporation at 79.3 x 10(5)lha(-1) yielded similar gross fish production as recorded from fertilizer based system, whereas net water productivity using sewage as nutrient source was found 64% higher than that of a fertilizer based system.
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108
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Saha A, Mandal P, Dasgupta S, Saha D. Influence of culture media and environmental factors on mycelial growth and sporulation of Lasiodiplodia theobromae (Pat.) Griffon and Maubl. JOURNAL OF ENVIRONMENTAL BIOLOGY 2008; 29:407-410. [PMID: 18972700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Lasiodiplodia theobromae, a common tea (Camellia sinensis) pathogen, usually does not sporulate or sporulates poorly in common media, which makes spore production difficult. In this study the effects of culture media, carbon source, nitrogen source, temperature, pH and light on mycelial growth and sporulation were evaluated. Among several carbon sources tested, glucose and sucrose were found superior for growth. Potassium nitrate supplemented media showed maximum growth amongst the tested inorganic nitrogen sources while peptone produced maximum growth among the tested organic nitrogen sources. Tea root extract supplemented potato dextrose agar medium was found to be the most suitable for mycelial growth and sporulation of L. theobromae. The fungus grow at temperatures ranging from 40 to 36 degrees C, with optimum growth at 28 degrees C and no growth was noted at 40 degrees C. There was no significant effect of different light period on growth of L. theobromae, but light enhanced sporulation. The fungus grow at pH 3.0-8.0 and optimum growth was observed at pH 6.0. Tea root extract supplemented potato dextrose agar medium with pH 6.0 was the most suitable for production of conidia of L. theobromae at 28 degrees C. Hence this media may be recommended for inoculum production for further studies.
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Kaveri SV, Dasgupta S, Andre S, Navarrete AM, Repessé Y, Wootla B, Lacroix-Desmazes S. Factor VIII inhibitors: role of von Willebrand factor on the uptake of factor VIII by dendritic cells. Haemophilia 2008; 13 Suppl 5:61-4. [PMID: 18078399 DOI: 10.1111/j.1365-2516.2007.01575.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In patients with haemophilia A, factor VIII (FVIII) therapy leads to the development of anti-FVIII alloantibodies that inhibit FVIII pro-coagulant activity, in up to 25% of the cases. At a time when efficient viral screening procedures are at place, development of inhibitors poses the greatest threat to haemophilia A patients. Various risk factors, both patient and product-related, are responsible for the development of inhibitory antibodies. The role of FVIII-specific CD4+ T lymphocytes in the initiation of the humoral immune response to exogenous FVIII has been well. In view of their capacity to stimulate naïve T cells, dendritic cells (DCs) play a central role in the initiation of the primary immune response. Thus, in the context of a primary alloimmunization against FVIII, i.e. when FVIII-specific B lymphocytes are not there to take up FVIII from the circulation and to serve as antigen presenting cells (APCs), DCs are the only cell type that internalize FVIII, leading to activation of FVIII-specific CD4+ T lymphocytes. von Willebrand factor (VWF) present in plasma-derived FVIII therapeutic concentrates, is known to act as a chaperone molecule for procoagulant FVIII. In addition to its role in reducing the 'antigenicity' of FVIII, the role of VWF in the reduction of the 'immunogenicity' of therapeutic FVIII in patients with haemophilia A has also been suggested. We have recently demonstrated that VWF protects FVIII from being endocytosed by human DCs and subsequently being presented to FVIII-specific T cells. We propose that VWF may reduce the immunogenicity of FVIII by preventing, upstream from the activation of immune effectors, the entry of FVIII in professional antigen presenting cells.
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Dasgupta S, Navarrete AM, Andre S, Wootla B, Delignat S, Repesse Y, Bayry J, Nicoletti A, Saenko EL, d'Oiron R, Jacquemin M, Saint-Remy JM, Kaveri SV, Lacroix-Desmazes S. Factor VIII bypasses CD91/LRP for endocytosis by dendritic cells leading to T-cell activation. Haematologica 2008; 93:83-9. [DOI: 10.3324/haematol.11535] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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111
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Kim MS, Chang X, Nagpal JK, Yamashita K, Baek JH, Dasgupta S, Wu G, Osada M, Woo JH, Westra WH, Trink B, Ratovitski EA, Moon C, Sidransky D. The N-methyl-D-aspartate receptor type 2A is frequently methylated in human colorectal carcinoma and suppresses cell growth. Oncogene 2007; 27:2045-54. [DOI: 10.1038/sj.onc.1210842] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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112
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Delignat S, Dasgupta S, Andre S, Navarrete AM, Kaveri SV, Bayry J, Andre MH, Chtourou S, Tellier Z, Lacroix-Desmazes S. Comparison of the immunogenicity of different therapeutic preparations of human factor VIII in the murine model of hemophilia A. Haematologica 2007; 92:1423-6. [DOI: 10.3324/haematol.11438] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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113
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Dasgupta S, Adams JA, Hogan EL. Maternal alcohol consumption increases sphingosine levels in the brains of progeny mice. Neurochem Res 2007; 32:2217-24. [PMID: 17701351 DOI: 10.1007/s11064-007-9445-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Accepted: 07/13/2007] [Indexed: 10/23/2022]
Abstract
The effect of 'binge' alcohol upon sphingolipid metabolism in the fetal alcohol syndrome (FAS) was examined in pregnant mice (C57BL/6J) by administering a single dose of alcohol during the third trimester (gestational day 15-16). The control mice were administered a sucrose solution of equal caloric value. Brains from progeny at postnatal days 5, 15, 21 and 30 were dissected into three regions, and sphingolipid concentrations of the brain regions were determined including assay of monoglycosylceramide, ceramide, sphingosine and sphingomyelin. We found that a single dose of ethanol induces an elevation of sphingosine (2-3.5-fold) in the brain of progeny. The level of brain ceramide at a dose of 1.5 g/kg was significantly higher than control. Alcohol consumption during pregnancy induces neuronal loss in progeny brains. Our result suggests that the elevation of sphingosine in progeny brain induced by maternal alcohol consumption may be responsible for observed neuronal loss in FAS.
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Dasgupta S, Taylor KE, Bewtra JK, Biswas N. Inactivation of enzyme laccase and role of cosubstrate oxygen in enzymatic removal of phenol from water. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2007; 79:858-67. [PMID: 17824532 DOI: 10.2175/106143007x175825] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Research was conducted to evaluate the potential use of laccase and its susceptibility to inactivation in an alternative enzyme-based treatment technology to remove parent phenol from buffered distilled water. Enzymatic oxidative polymerization of phenol with laccase was carried out in continuously stirred batch reactors. The reaction products were insoluble polymers, which precipitated out of the solution once their solubility limits were exceeded. The findings demonstrated that the polymeric products had significant effects on enzyme activity consumption and subsequent phenol removal. Enzyme species present in the reaction vessel were classified into enzyme remaining in the solution (type 1) and enzyme adhering to the precipitate polymers (type 2). Type 1 enzyme was more efficient in removal of phenol from solution compared with type 2. Subsequent filtration enhanced the phenol removal by removing type 2 enzyme adhering to the polymer particles and decelerating enzyme inactivation. The study also investigated the effects of available dissolved oxygen, provided through aeration and hydrogen peroxide addition, on phenol removal. Aeration and hydrogen peroxide addition increased the dissolved oxygen concentration, but had no effect on the progress curve for phenol removal.
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Delignat S, Dasgupta S, Navarrete A, Kaveri S, Tellier Z, Chtourou S, Lacroix-Desmazes S. COMPARISON OF THE IMMUNOGENICITY OF DIFFERENT THERAPEUTIC PREPARATIONS OF HUMAN FACTOR VIII IN THE MURINE MODEL OF HEMOPHILIA A. J Thromb Haemost 2007. [DOI: 10.1111/j.1538-7836.2007.tb01073.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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116
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Feleppa E, Dasgupta S, Porter C, Ramachandran S, Ketterling J, Kalisz A, Lacrampe M, Isaacson C. SU-FF-I-101: Combining Magnetic-Resonance Spectroscopy and Ultrasound Spectral Parameters to Improve Tissue-Type Imaging of Prostate Cancer. Med Phys 2007. [DOI: 10.1118/1.2760478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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117
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Das P, Ray SK, Joardar GK, Dasgupta S. Nutritional profiles of adolescents in a rural community of Hooghly district in West Bengal. Indian J Public Health 2007; 51:120-121. [PMID: 18240475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
This community based study was carried out in Haripal Block of Hooghly district in West Bengal in 2005 to assess the nutritional status of the unmarried adolescents and 204 adolescents were studied. The BMI for age and height for age < 5th percentile were used as criteria for thinness and stunting respectively. The overall prevalence of thinness and stunting were 24.48% and 52.45%, thinness was more common among the boys. The other nutritional deficiency disorders were pallor (12.25%), conjunctival xerosis (9.30%), Vitamin B complex deficiency (1.47%), goitre (0.98%) and dental caries (11.76%). An indication of chronic energy deficiency in the study area was observed.
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Das AK, Jana N, Dasgupta S, Samanta B. Intrapartum transcervical amnioinfusion for meconium-stained amniotic fluid. Int J Gynaecol Obstet 2007; 97:182-6. [PMID: 17368644 DOI: 10.1016/j.ijgo.2007.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 12/31/2006] [Accepted: 01/17/2007] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To assess the rates of cesarean deliveries and perinatal outcome following intrapartum transcervical amnioinfusion in women with meconium-stained amniotic fluid (MSAF) in a setting with no electronic fetal monitoring or specialized neonatal care. MATERIALS AND METHODS In this prospective comparative study with 150 women who were in labor and had MSAF, 50 of the women received a transcervical amnioinfusion and the remaining 100 women received standard care. The inclusion criteria were a pregnancy of at least 37 weeks' duration, a single live fetus in cephalic presentation, no major medical or obstetric complications, and no known fetal malformation. The amnioinfusion was performed with 1000 mL of normal saline solution through a red rubber catheter. RESULTS Amnioinfusion was associated with a significant decrease in the incidence of low Apgar score (<7) at 1 min (12% vs. 47%; relative risk [RR], 0.26; 95% confidence interval [CI], 0.12-0.56); low Apgar score at 5 min (4% vs. 23%; RR, 0.17; 95% CI, 0.04-0.71); and meconium aspiration syndrome (4% vs. 18%; RR, 0.22; 95% CI, 0.05-0.92). There was also a trend towards a lesser incidence of cesarean deliveries (18% vs. 30%; RR, 0.6; 95% CI, 0.31-1.16) and perinatal deaths (4% vs. 13%; RR, 0.31; 95% CI, 0.07-1.31). The incidence of maternal hospital stays longer than 3 days was significantly lower in the amnioinfusion than in the control group (24% vs. 48%; RR, 0.5; 95% CI, 0.29-0.85). There were no major complications related to amnioinfusion. CONCLUSIONS Intrapartum amnioinfusion for MSAF is a simple, safe, effective, and inexpensive procedure feasible in settings where intrapartum monitoring is limited. It is associated with improved perinatal outcome and could lower cesarean delivery rates in low-resource countries.
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Banerjee P, Dasgupta S, De S. Removal of dye from aqueous solution using a combination of advanced oxidation process and nanofiltration. JOURNAL OF HAZARDOUS MATERIALS 2007; 140:95-103. [PMID: 16876933 DOI: 10.1016/j.jhazmat.2006.06.075] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 05/31/2006] [Accepted: 06/19/2006] [Indexed: 05/11/2023]
Abstract
In order to have energy and cost effective separation of dyes, a combination of advanced oxidation process (AOP) using Fenton's reagent and nanofiltration (NF) is proposed. Three combinations of AOP and NF are studied using a synthetic solution of eosin dye. Scheme-1 is AOP followed by NF. Scheme-2 is NF followed by AOP. And Scheme-3 is two-step NF. The concentration of eosin dye studied in the first step of each of the schemes is in the range of 70-200mg/l. The operating transmembrane pressures for NF steps are 552, 689 and 828kPa. The crossflow velocities are 0.46, 0.69 and 0.91m/s. The schemes are compared for permeate flux, permeate concentration and duration of operation. In Scheme-1, AOP is conducted for 30min, and then subjected to NF, whereas in Scheme-2, the time needed for AOP is more than 3h to achieve the concentration level of the dye below 1mg/l. Thus, it is found that Scheme-1 is superior to Scheme-2 due to lesser time requirement. However, Scheme-3 involving no AOP, is also suitable for dye separation as the final eosin concentration in the permeate falls below 1mg/l. Scheme-1 is found suitable for dye concentration of 70mg/l and the most appropriate composition of Fenton's reagent is 1665mg/l of H(2)O(2) and 347.5mg/l of FeSO(4)x7H(2)O. Suitable NF operating conditions in step 2 of Scheme-1 is transmembrane pressure of 689kPa and crossflow velocity of 0.91m/s. In Scheme-3, the suitable operating conditions for NF in both the steps are 828kPa transmembrane pressure and 0.91m/s crossflow velocity. Scheme-2 is found to be unsuitable.
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Imrie J, Dasgupta S, Besley GTN, Harris C, Heptinstall L, Knight S, Vanier MT, Fensom AH, Ward C, Jacklin E, Whitehouse C, Wraith JE. The natural history of Niemann-Pick disease type C in the UK. J Inherit Metab Dis 2007; 30:51-9. [PMID: 17160617 DOI: 10.1007/s10545-006-0384-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 10/20/2006] [Accepted: 11/13/2006] [Indexed: 10/23/2022]
Abstract
Niemann-Pick disease type C (NPC) is an autosomal recessive, neurovisceral lipid storage disorder. Mutations in two genes (NPC1 and NPC2) produce indistinguishable clinical phenotypes by biochemical mechanisms that have not yet been entirely clarified. The wide spectrum of clinical presentations of NPC includes hepatic and pulmonary disease as well as a range of neuropsychiatric disorders. Late-onset disease has been increasingly recognized as the biochemical diagnosis of NPC has been more widely applied in adult neurology clinics. The clinical presentation and follow-up of 94 patients with NPC is described, 58 of whom were still alive at the time this report was prepared. The age at diagnosis ranged from the prenatal period (with hydrops fetalis) up to 51 years. This review of NPC patients in the UK confirms the phenotypic variability of this inherited lipid storage disorder reported elsewhere. Although a non-neuronopathic variant has been described, most patients in this series who survived childhood inevitably suffered neurological and in some cases neuropsychiatric deterioration. While symptomatic treatment, such as anticholinergic and antiepileptic drugs, can alleviate some aspects of the disease, there is a clear need to develop a specific treatment for this progressively debilitating neurodegenerative disorder.
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Feleppa E, Porter C, Ketterling J, Dasgupta S, Ramachandran S, Sparks D. Recent Advances in Ultrasonic Tissue-Type Imaging of the Prostate. ACOUSTICAL IMAGING 2007. [DOI: 10.1007/1-4020-5721-0_35] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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122
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Maji R, Bhattacharyya S, Dasgupta S, Bandyopadhyay S, Mukhopadhyay R, Deuri AS. Improvement of polymer blend properties by changing sequence of mixing. J Appl Polym Sci 2007. [DOI: 10.1002/app.25832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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123
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Mandal NK, Mallik S, Roy RP, Mandal SB, Dasgupta S, Mandal A. Impact of religious faith & female literacy on fertility in a rural community of west Bengal. Indian J Community Med 2007. [DOI: 10.4103/0970-0218.53382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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124
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Sengupta R, Chakraborty S, Bandyopadhyay S, Dasgupta S, Mukhopadhyay R, Auddy K, Deuri A. A short review on rubber/clay nanocomposites with emphasis on mechanical properties. POLYM ENG SCI 2007. [DOI: 10.1002/pen.20921] [Citation(s) in RCA: 208] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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125
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Dasgupta S, Huq M, Khaliquzzaman M, Pandey K, Wheeler D. Indoor air quality for poor families: new evidence from Bangladesh. INDOOR AIR 2006; 16:426-44. [PMID: 17100664 DOI: 10.1111/j.1600-0668.2006.00436.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Poor households in Bangladesh depend heavily on wood, dung and other biomass fuels for cooking. This paper provides a detailed analysis of the implications for indoor air pollution (IAP), drawing on new 24-h monitoring data for respirable airborne particulates (PM10). A stratified sample of 236 households was selected in Dhaka and Narayanganj, with a particular focus on fuel use, cooking locations, structural materials, ventilation practices, and other potential determinants of exposure to IAP. At each household, PM10 concentrations in the kitchen and living room were monitored for a 24-h period during December, 2003-February, 2004. Concentrations of 300 microg/m3 or greater are common in our sample, implying widespread exposure to a serious health hazard. A regression analysis for these 236 households was then conducted to explore the relationships between PM10 concentrations, fuel choices and a large set of variables that describe household cooking and ventilation practices, structure characteristics and building materials. As expected, our econometric results indicate that fuel choice significantly affects indoor pollution levels: natural gas and kerosene are significantly cleaner than biomass fuels. However, household-specific factors apparently matter more than fuel choice in determining PM10 concentrations. In some biomass-burning households, concentrations are scarcely higher than in households that use natural gas. Our results suggest that cross-household variation is strongly affected by structural arrangements: cooking locations, construction materials, and ventilation practices. A large variation in PM10 was also found during the 24-h cycle within households. For example, within the 'dirtiest' firewood-using household in our sample, readings over the 24-h cycle vary from 68 to 4864 microg/m3. Such variation occurs because houses can recycle air very quickly in Bangladesh. After the midday meal, when ventilation is common, air quality in many houses goes from very dirty to reasonably clean within an hour. Rapid change also occurs within households: diffusion of pollution from kitchens to living areas is nearly instantaneous in many cases, regardless of internal space configuration, and living-area concentrations are almost always in the same range as kitchen concentrations. By implication, exposure to dangerous indoor pollution levels is not confined to cooking areas. To assess the broader implications for poor Bangladeshi households, we extrapolate our regression results to representative 600 household samples from rural, peri-urban and urban areas in six regions: Rangpur in the north-west, Sylhet in the north-east, Rajshahi and Jessore in the west, Faridpur in the center, and Cox's Bazar in the south-east. Our results indicate great geographic variation, even for households in the same per capita income group. This variation reflects local differences in fuel use and, more significantly, construction practices that affect ventilation. For households with per capita income <US Dollars 1.00/day, rural PM10 concentrations vary from 410 microg/m3 in Cox's Bazar to 202 microg/m3 in Faridpur. In urban areas, concentrations for such households differ by almost 100 microg/m3 between the highest areas, Jessore and Rajshahi, and the lowest, Sylhet. Practical Implications Our analysis suggests that poor families may not have to wait for clean fuels or clean stoves to enjoy significantly cleaner air. Within our sample household population, some arrangements are already producing relatively clean conditions, even when 'dirty' biomass fuels are used, such as simple changes in ventilation characteristics of housing (construction materials, space configurations, cooking locations and placement of doors and windows) and ventilation behavior (keeping doors and windows open after cooking). As these arrangements are already within the means of poor families, the scope for cost-effective improvements may be larger than is commonly believed.
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