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Biomedical subjects

M Alauddin

Publications and source records attributed to M Alauddin.

16 recordsLinked to original sources
PubMed2003

Chemical fate of arsenic and other metals in groundwater of Bangladesh: experimental measurement and chemical equilibrium model.

The presence of toxic level of inorganic arsenic in groundwater used for drinking in Bangladesh and neighboring India is unfolding as one of the worst natural disaster in the region. The purpose of this work is to ascertain the chemical fate of arsenic and other metals in groundwater of Bangladesh. A combination of techniques was used to measure 24 metals, 6 anions, Eh, pH, dissolved oxygen, conductivity, and temperature to understand the distribution of components which were then used in computational chemical equilibrium model, MINEQL+, for detailed speciation. It was found that the fate of arsenic and its speciation were inextricably linked to the formation of hydrous ferric oxide (HFO) and its kinetic. The HFO induced natural attenuation removes 50-75% of total arsenic in first 24 h through a first order kinetics. Adsorption on HFO is the predominant mode of removal of arsenic, iron, manganese, and most trace metals. The equilibrium model points to the presence of excess active sites for the removal of arsenic. MINEQL+ shows that significantly higher concentration of HFO forming iron is required to remove arsenic below maximum contamination level (MCL) of 50 microg/L than predicted by stoichiometry. The practical implication of this work is the prediction of water quality based on models.

Arsenic↗
PubMed2002

Solid phase microextraction: measurement of volatile organic compounds (VOCs) in Dhaka City air pollution.

A solid phase microextraction (SPME) technique was applied for the sampling of volatile organic compounds (VOCs) in ambient air polluted by two stroke autorickshaw engines and automobile exhausts in Dhaka city, Bangladesh. Analysis was carried out by capillary gas chromatography (GC) and GC-mass spectrometry (MS). The methodology was tested by insitu sampling of an aromatic hydrocarbon mixture gas standard with a precision of +/-5% and an average accuracy of 1-20%. The accuracy for total VOCs concentration measurement was about 7%. VOC's in ambient air were collected by exposing the SPME fiber at four locations in Dhaka city. The chromatograms showed signature similar to that of unburned gasoline (petrol) and weathered diesel containing more than 200 organic compounds; some of these compounds were positively identified. These are normal hydrocarbons pentane (n-C5H2) through nonacosane (n-C29H60), aromatic hydrocarbons: benzene, toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, 1,3,5-trimethylbenzene, xylenes, and 1-isocyanato-3-methoxybenzene. Two samples collected near an autorickshaw station contained 783000 and 1479000 microg/m3 of VOCs. In particular, the concentration of toluene was 50-100 times higher than the threshold limiting value of 2000 microg/m3. Two other samples collected on street median showed 135000 microg/m3 and 180000 microg/m3 of total VOCs. The method detection limit of the technique for most semi-volatile organic compounds was 1 microg/m3.

Air Pollutants↗
PubMed2002

Carcinoma larynx--topographical distribution.

One hundred and sixty subjects were included in our study, collected from four hospitals in Dhaka City. The mean age (+/- SD) of study subjects were 54.67 +/- 11.27 years. Out of 160 subjects 155 was males and 5 were females, and male to female ratio was 31:1. The highest number of study subjects was related to cultivation (40.62%). The majority of study subjects were from the low socio-economic status (68.72%). Carcinoma larynx is a multifactorial disease. Smoking and chewing habit are the most important factors associated with carcinoma larynx. Most of the male (93.12%) subjects were smoker. One hundred and fifteen (71.87%) subjects were found chewing habit of betel leaves with other ingredients. Hoarseness of voice was the commonest symptom 65.62%. Regional distribution of tumour showed supraglottic carcinoma topping the list (69.38%) followed by glottic carcinoma (30.62%) and there was no subglottic carcinoma. Site involvement in supraglottic carcinoma was found in combined location topping the list (89.20%). In glottic carcinoma majority was found glottic with supraglottic extension (65.31%). In majority cases growth were exophytic 52.50%. Palpable lymph mode was found in 48.75% of cases. All the carcinoma of larynx was found histologically of squamous cell type.

Adult↗
PubMed2002

Comparative study between tubotympanic and atticoantral types of chronic suppurative otitis media.

This prospective study was done to compare the different aspects of tubotympanic (group I) and atticoantral types (group II) of chronic suppurative otitis media. The study included 200 patients of chronic suppurative otitis media, of them 100 were of tubotympanic type and 100 were with atticoantral disease. The age (mean +/- SD) of group I and II were 17 +/- 2.7 years and 12 +/- 2.3 years respectively (P < 0.05). The majority of the patients having poor socio-economic condition 69% in group I and 87% in-group II. In both groups, slum dwellers with bathing habit in pond or river and illiterate were more sufferer (P < 0.05). There was central perforation in all patients in-group I, and in-group II, 67% were with attic and 33% were with marginal perforations. In group I, aural discharge was mucoid or mucopurulent in majority of cases 80% and in-group II foul smelling scanty ear discharge was from 88% of subjects. In atticoantral type, hearing impairment was more than tubotympanic disease. Complications were more in atticoantral type of disease. In-group II, post auricular sinus 25% was the commonest extracranial complication followed by subperiosteal abscess 18%, and meningitis 10% was the commonest intracranial complication followed by brain abscess 8%. In tubotympanic type conservative treatment with reconstructive surgery were the treatment of choice, whereas radical or some modifications of radical surgery (with or without reconstruction) were the treatment plan for atticoantral disease. Among the groups the mortality rate was only 4% in-group II and was due to intracranial complications. The study recommends early detection and effective surgical treatment of the disease to improve the situation.

Adolescent↗
PubMed1997

Synthesis and in vitro activity of 3 beta-substituted-3 alpha-hydroxypregnan-20-ones: allosteric modulators of the GABAA receptor.

Two naturally occurring metabolites of progesterone, 3 alpha-hydroxy-5 alpha- and 5 beta-pregnan-20-one (1 and 2), are potent allosteric modulators of the GABAA receptor. Their therapeutic potential as anxiolytics, anticonvulsants, and sedative/hypnotics is limited by rapid metabolism. To avoid these shortcomings, a series of 3 beta-substituted derivatives of 1 and 2 was prepared. Small lipophilic groups generally maintain potency in both the 5 alpha- and 5 beta-series as determined by inhibition of [35S]TBPS binding. In the 5 alpha-series, 3 beta-ethyl, -propyl, -trifluoromethyl and -(benzyloxy)methyl, as well as substituents of the form 3 beta-XCH2, where X is Cl, Br, or I or contains unsaturation, show limited efficacy in inhibiting [35S]TBPS binding. In the 5 beta-series, the unsubstituted parent 2 is a two-component inhibitor, whereas all of the 3 beta-substituted derivatives of 2 inhibit TBPS via a single class of binding sites. In addition, all of the 3-substituted 5 beta-sterols tested are full inhibitors of [35S]TBPS binding. Electrophysiological measurements using alpha 1 beta 2 gamma 2L receptors expressed in oocytes show that 3 beta-methyl- and 3 beta-(azidomethyl)-3 alpha-hydroxy-5 alpha-pregnan-20-one (6 and 22, respectively) are potent full efficacy modulators and that 3 alpha-hydroxy-3 beta-(trifluoromethyl)-5 alpha-pregnan -20-one (24) is a low-efficacy modulator, confirming the results obtained from [35S]TBPS binding. These results indicate that modification of the 3 beta-position in 1 and 2 maintains activity at the neuroactive steroid site on the GABAA receptor. In animal studies, compound 6 (CCD 1042) is an orally active anticonvulsant, while the naturally occurring progesterone metabolites 1 and 2 are inactive when administered orally, suggesting that 3 beta-substitution slows metabolism of the 3-hydroxyl, resulting in orally bioavailable steroid modulators of the GABAA receptor.

Animals↗
PubMed1991

Enhanced tumor uptake of macromolecules induced by a novel vasoactive interleukin 2 immunoconjugate.

Low uptake of monoclonal antibodies (MAbs) in cancer lesions is a significant problem in cancer therapy. Recent studies have shown that antibody uptake in tumor is controlled in large part by the tumor blood flow and the vascular permeability of the tumor endothelium. We have hypothesized that these physiological properties of tumor vessels may be altered by pretreatment with vasoactive drugs or peptides linked to tumor-specific MAbs. To test this hypothesis, two MAbs, Lym-1 directed against human malignant lymphomas and B72.3 reactive with the TAG-72 antigen expressed in solid tumors, were chemically conjugated with human recombinant interleukin 2 (IL-2). IL-2 has been used in humans to activate lymphokine-activated killer cells for the treatment of cancer but is also known to produce a generalized vascular permeability by an unknown mechanism when used systemically. Chemical conjugation of IL-2 to MAbs appears to destroy its cytokine function as shown by T-cell proliferation studies in vitro. Despite this finding, MAb/IL-2 immunoconjugates retain their ability to produce an enhanced vascular permeability when injected i.v. into nude mice bearing relevant tumor models only. Biodistribution studies using 125I-labeled tracer Lym-1 have demonstrated that the Lym-1/IL-2 immunoconjugate can increase antibody uptake in tumor by a factor of 4 in a time (2.5-h pretreatment)- and dose (30 micrograms/mouse)-dependent manner. In contrast, treatment of mice with free IL-2 and antibody showed this effect in all organs of the mouse including the tumor. Bidirectional crossover imaging studies in individual tumor-bearing nude mice showed improved uptake and decreased blood pool when the MAb/IL-2 immunoconjugates were used compared to controls. Finally, tumor blood flow and vascular permeability studies demonstrate that the physiological effect of the MAb/IL-2 is due to a reversible and specific vascular leakage at the tumor site. These studies indicate that pretreatment with this novel immunoconjugate may enhance the diagnostic and therapeutic potential of MAbs, drugs, and other macromolecules for the treatment of cancer.

Animals↗
PubMed1986

Brain trace elements in Alzheimer's disease.

Instrumental neutron activation analysis has been used to determine the concentrations of 16 elements in selected brain regions and separated gray- and white-matter specimens from histologically verified Alzheimer's disease (AD) and age-matched control patients. Significantly different (p less than 0.05) mean concentrations of Br, Cl, Cs, Hg, N, Na, P, and Rb were observed in AD bulk brain samples compared to controls, while no significant differences were observed for Ag, Co, Cr, Fe, K, Sb, Sc, and Se. The differences that are most persistent and largest in magnitude for the pooled bulk samples, males and females, left and right hemispheres, and separated gray and white matter are the elevation of Br and Hg and the depletion of Rb in AD compared to controls. Significant interelement correlations for the latter elements in both AD and control brains are also documented. Based on these studies, the possibility of an etiological role for trace elements in AD clearly deserves further investigation.

Aged↗
PubMed1984

Brain trace elements in Pick's disease.

The trace element content of the brain of two patients with Pick's disease examined postmortem was studied using instrumental neutron activation analysis. Results showed significant increases in chlorine, iron, manganese, sodium, and phosphorus and significant decreases in chromium, cesium, rubidium, and selenium and in the mean freeze-dried to wet-weight ratio for patients with Pick's disease compared with control patients. Brain zinc content was not elevated in the two patients, a finding that fails to support the hypothesis that elevated zinc levels play a role in the pathogenesis of Pick's disease.

Aged↗
PubMed1984

Brain trace element concentrations in aging.

Trace element concentrations were determined in various human brain regions over the complete life span using instrumental neutron activation analysis. Several different patterns of trace element alteration were observed with age. Brain Al, Cl and Na concentrations increase with advancing age, while K, P and Rb decline. Ag, Co, Fe, Sb and Sc concentrations increase up to the 40 to 79 age range then decline. Br, Se and Zn remain relatively constant throughout adult life. Hg, Mn and Cs show no consistent trend with age. In infant brains Br and Cl increase and Al, Cr, Cs, Fe, Mn, P, Rb, Sc, Se and Zn decrease compared to adults. The essential elements that remain within narrow concentration limits throughout adult life suggest the presence of an efficient homeostatic mechanism for their regulation in the brain, while those that are altered with age suggest modifications in control mechanisms or altered relationships with other elements. Increased concentrations of non-essential elements may reflect accumulation from our environment, impaired removal or altered balance with other elements.

Adult↗
PubMed1984

Brain manganese concentrations in human aging and Alzheimer's disease.

Manganese levels have been measured in various brain regions in Alzheimer's disease (AD) and aging using instrumental neutron activation analysis. Mn grand mean for all regions was 0.261 micrograms/g for adult controls and 0.245 micrograms/g for AD and the differences were not statistically significant (p less than 0.05). Highest Mn levels were found in the basal ganglia in controls and AD. No significant alterations in Mn were found with advancing age suggesting that the brain has an efficient homeostatic mechanism regulating Mn concentrations. Mn exhibited a significant positive correlation with Fe. Infants had a significantly lower brain Mn level compared to adults.

Adult↗
PubMed1981

Instrumental neutron activation analysis of brain aluminum in Alzheimer disease and aging.

Instrumental neutron activation analysis procedures were used to determine the aluminum content of various brain regions in histologically verified Alzheimer disease (AD) and in controls. The grand mean aluminum level for 74 AD specimens was 0.372 +/- 0.058 microgram/gm and for 137 adult controls, 0.467 +/- 0.033 microgram/gm, both on a wet weight basis. No difference was found at the bulk sample level between AD and adult controls, corrected for age and sex, or when frontal, temporal, and hippocampal specimens were compared. Control specimens (infancy to 85 years) showed an increase in brain aluminum concentration with age. Comparison of freeze-dried to wet weight ratios of AD and controls revealed a small increase in water content in AD brains.

Adolescent↗
PubMedDate not supplied

Maternal mortality in rural Bangladesh: the Tangail District.

A study was conducted from September 1982 to August 1983 in the Tangail district of Bangladesh to estimate the maternal mortality level there and identify its causes and correlates. A rate of 56.6 per 10,000 live births was found, with abortion-related deaths contributing nearly 10 deaths per 10,000 live births. The major causes of maternal mortality were found to be obstructed labor and sepsis caused by improperly performed abortion. Those at high risk were mothers below age 20 and above age 30 and those above parity four. No inverse relationship was found between maternal mortality and socioeconomic status, as might be expected. Community-level pregnancy monitoring programs, increased attention on the part of family planning workers toward teenaged, older, and high parity mothers, and nutrition supplement programs for anemic mothers are recommended.

Adolescent↗