PubMed Health⌕ Search

Biomedical subjects

M M Rahman

Publications and source records attributed to M M Rahman.

At least 73 records · Page 4Linked to original sources
PubMed1999

Simultaneous vitamin A administration at routine immunization contact enhances antibody response to diphtheria vaccine in infants younger than six months.

A randomized, double-blind, placebo-controlled trial was conducted to evaluate the effect of simultaneous vitamin A supplementation and diphtheria, pertussis and tetanus (DPT) vaccination on the antibody levels. Infants aged 6-17 wk (n = 56) were randomly given 15 mg oral vitamin A or placebo at the time of their DPT immunization. Three such doses were given at monthly intervals. Immunoglobulin (Ig) G antibodies to diphtheria, pertussis and tetanus were assayed on enrollment and 1 mo after the third dose. Baseline antibody concentrations to diphtheria, pertussis and tetanus did not differ between the vitamin A-supplemented and placebo-treated groups. The postdose antibody to diphtheria level was significantly greater in the vitamin A than in the placebo-treated group. The geometric mean +/- SEM antibody levels (mg/L) were 22.9 +/- 1.2 and 11.0 +/- 1.3 in the vitamin A and placebo groups, respectively (P = 0.029). The postsupplementation concentrations of antibodies to pertussis and tetanus did not differ between the two groups. These results suggest that antibody response to diphtheria vaccination was potentiated by simultaneous vitamin A administration and DPT immunization.

Antibodies, Bacterial↗
PubMed1999

Long-term supplementation with iron does not enhance growth in malnourished Bangladeshi children.

To evaluate the effect of long-term oral iron supplementation on growth, 250 children aged 6-71 mo were studied in a randomized double-blind controlled trial. The intervention group received 125 mg of ferrous gluconate (15 mg elemental iron) plus multivitamins (vitamins A, D and C); the comparison group received only multivitamins daily for 12 mo. Weight (kg) and height (cm) were measured every month. Eighty three percent of the children continued the treatment for one year. The weight increment over the 12-mo period was 1.35 +/- 0.65 kg (mean +/- SD) in the intervention group and 1.39 +/- 0.54 kg in the comparison group. The height increments were 6.01 +/- 1.47 and 6.18 +/- 1.58 cm in the intervention and comparison groups, respectively. Mean weight and height increments did not differ; in an analysis stratified according to different age and nutritional categories, they also did not differ between the two groups, indicating that long-term iron supplementation does not increase growth in children.

Analysis of Variance↗
PubMed1999

Lysogenic conversion of environmental Vibrio mimicus strains by CTXPhi.

The filamentous bacteriophage CTXPhi, which encodes cholera toxin (CT) in toxigenic Vibrio cholerae, is known to propagate by infecting susceptible strains of V. cholerae by using the toxin coregulated pilus (TCP) as its receptor and thereby causing the origination of new strains of toxigenic V. cholerae from nontoxigenic progenitors. Besides V. cholerae, Vibrio mimicus strains which are normally TCP negative have also been shown to occasionally produce CT and cause diarrhea in humans. We analyzed nontoxigenic V. mimicus strains isolated from surface waters in Bangladesh for susceptibility and lysogenic conversion by CTXPhi and studied the expression of CT in the lysogens by using genetically marked derivatives of the phage. Of 27 V. mimicus strains analyzed, which were all negative for genes encoding TCP but positive for the regulatory gene toxR, 2 strains (7.4%) were infected by CTX-KmPhi, derived from strain SM44(P27459 ctx::km), and the phage genome integrated into the host chromosome, forming stable lysogens. The lysogens spontaneously produced infectious phage particles in the supernatant fluids of the culture, and high titers of the phage could be achieved when the lysogens were induced with mitomycin C. This is the first demonstration of lysogenic conversion of V. mimicus strains by CTXPhi. When a genetically marked derivative of the replicative form of the CTXPhi genome carrying a functional ctxAB operon, pMSF9.2, was introduced into nontoxigenic V. mimicus strains, the plasmid integrated into the host genome and the strains produced CT both in vitro and inside the intestines of adult rabbits and caused mild-to-severe diarrhea in rabbits. This suggested that in the natural habitat infection of nontoxigenic V. mimicus strains by wild-type CTXPhi may lead to the origination of toxigenic V. mimicus strains which are capable of producing biologically active CT. The results of this study also supported the existence of a TCP-independent mechanism for infection by CTXPhi and showed that at least one species of Vibrio other than V. cholerae may contribute to the propagation of the phage.

Animals↗
PubMed1999

Molecular characterization of a new ribotype of Vibrio cholerae O139 Bengal associated with an outbreak of cholera in Bangladesh.

Vibrio cholerae O139 Bengal initially appeared in the southern coastal region of Bangladesh and spread northward, causing explosive epidemics during 1992 and 1993. The resurgence of V. cholerae O139 during 1995 after its transient displacement by a new clone of El Tor vibrios demonstrated rapid changes in the epidemiology of cholera in Bangladesh. A recent outbreak of cholera in two north-central districts of Bangladesh caused by V. cholerae O139 led us to analyze strains collected from the outbreak and compare them with V. cholerae O139 strains isolated from other regions of Bangladesh and neighboring India to investigate their origins. Analysis of restriction fragment length polymorphisms in genes for conserved rRNA (ribotype) revealed that the recently isolated V. cholerae O139 strains belonged to a new ribotype which was distinct from previously described ribotypes of toxigenic V. cholerae O139. All strains carried the genes for toxin-coregulated pili (tcpA and tcpI) and accessory colonization factor (acfB), the regulatory gene toxR, and multiple copies of the lysogenic phage genome encoding cholera toxin (CTXPhi) and belonged to a previously described ctxA genotype. Comparative analysis of the rfb gene cluster by PCR revealed the absence of a large region of the O1-specific rfb operon downstream of the rfaD gene and the presence of an O139-specific genomic region in all O139 strains. Southern hybridization analysis of the O139-specific genomic region also produced identical restriction patterns in strains belonging to the new ribotype and those of previously described ribotypes. These results suggested that the new ribotype of Bengal vibrios possibly originated from an existing strain of V. cholerae O139 by genetic changes in the rRNA operons. In contrast to previously isolated O139 strains which mostly had resistance to trimethoprim, sulfamethoxazole, and streptomycin encoded by a transposon (SXT element), 68.6% of the toxigenic strains analyzed in the present study, including all strains belonging to the new ribotype, were susceptible to these antibiotics. Molecular analysis of the SXT element revealed possible deletion of a 3.6-kb region of the SXT element in strains which were susceptible to the antibiotics. Thus, V. cholerae O139 strains in Bangladesh are also undergoing considerable reassortments in genetic elements encoding antimicrobial resistance.

Bangladesh↗
PubMed1999

Renal vasoconstriction induced by oxidized LDL is inhibited by scavengers of reactive oxygen species and L-arginine.

BACKGROUND: Low density lipoprotein (LDL) may be involved in the pathogenesis of glomerulosclerosis and progressive renal dysfunction associated with atherosclerotic renal artery stenosis (RAS). This study was undertaken to investigate the effects of native (n-LDL) and oxidized LDL (ox-LDL) on renal vascular response and function in an isolated perfused rat kidney (IPRK) model. MATERIAL AND METHOD: IPRK model was used for the study at a constant pressure of 100 mm of Hg in the renal artery with continuous monitoring of pressure and renal perfusate flow. Urine and perfusate samples were collected to determine [14C] Inulin clearance and fractional reabsorption of sodium. To elucidate the role of nitric oxide (NO) urinary c-GMP, nitrate and nitrite excretion were measured and the responses to the NO synthase inhibitor N-monomethyl-L-arginine (LNMMA) and the NO donor Nitroso-glutathione (GSNO) were assessed. The effect of L-arginine supplementation and the role of reactive oxygen species were also studied by adding superoxide dismutase (SOD) and catalase. RESULTS: Ox-LDL but not n-LDL caused vasoconstriction in IPRK, as evidenced by a significant dose dependent reduction in renal perfusate flow. [14C] Inulin clearance and fractional reabsorption of sodium were reduced during ox-LDL infusion whereas no significant change occured with n-LDL. There was a significant decrease in urinary excretion of c-GMP during ox-LDL infusion. 10 microM LNMMA significantly increased and GSNO (10 microM) significantly diminished the vasoconstrictory effect of ox-LDL. The presence of L-arginine (100 & 500 microM) significantly decreased ox-LDL induced vasoconstriction. SOD (150 U/ml) and catalase (1200 U/ml) both had a significant inhibitory effect and the combination of SOD and catalase almost completely abolished the vasoconstriction due to ox-LDL. CONCLUSION: These results suggest that ox-LDL induced vasoconstriction in IPRK is mediated by decreased activity of NO probably due to inactivation of NO by reactive oxygen species. The free radical scavengers SOD, catalase and L-arginine provided protection against ox-LDL induced vasoconstriction in this model.

Animals↗
PubMed1999

"Outbreak" of hand injuries during Hajj festivities in Saudi Arabia.

Pediatric hand surgeons in Europe and North America are aware of the yearly "outbreak" of pediatric hand injuries on Halloween from carving pumpkins. This study reports another yearly "outbreak" of hand injuries--in Saudi Arabia from slaughtering sheep. During the 3 days of festivities following the Hajj ceremony, hundreds of thousands of sheep are slaughtered. Over 4 consecutive years, 298 patients attended the emergency room of Riyadh Central Hospital with injuries related to the slaughtering of animals sustained during the 3 days of festivity. Almost three quarters of patients (73%) were injured on the first day of festivity. The majority (92%) were nonprofessionals. Children accounted for 6.7% of patients. In adults, the female-to-male ratio was 1:7. The most common mechanism of injury was a knife cut (80.9%). Almost three quarters of injuries (73.5%) affected the hands, with more involvement of the left than the right hand. Only 7.7% of patients with hand injuries were admitted to the hospital for treatment. It was concluded that implementing safety measures while slaughtering, and educating the general population would be important in the prevention of these hand injuries in Saudi Arabia.

Adult↗
PubMed1998

Helicobacter pylori infection in infants and children of Bangladesh.

Helicobacter pylori is an important cause of chronic gastritis and plays important roles in the etiology of peptic ulcer disease, gastric cancer and non-ulcer dyspepsia. While H. pylori infections occur worldwide, the great majority of information is from the developed countries, and little is known about the epidemiology of H. pylori in the developing countries, particularly in children.

Bangladesh↗
PubMed1998

Guidelines for force-travel combinations of push button switches for older populations.

Current demographic trends indicating that older persons will comprise an increasingly larger proportion of our population points to the need for paying closer attention to age-related disabilities in designing products and environments capable of accommodating this population. This study addresses the development of design guidelines for push-button switches associated with a variety of consumer products commonly used by older persons. Three groups, each consisting of 12 male and female subjects, participated in the study, with all subjects over the age of 50 and the average age being 70 years. The groups were categorized on the basis of whether subjects were able-bodied, had arthritis affecting their hands or fingers, or had hand tremor; these categories were validated through the use of functional assessment tools. A scheme was developed to categorize commercially available switches based on force-travel combinations, and an experiment was conducted to assess the subject's ability to momentarily and continuously operate the switches, as well as to derive the subjective preferences for these switches. Based on observations from behavioral strategies, and graphical and statistical analysis of preferences, a set of design guidelines was proposed to enable consumer product designers and manufacturers to better accommodate the needs of both able-bodied and functionally impaired older adults.

Activities of Daily Living↗
PubMed1998

The lipooligosaccharide (LOS) of Neisseria meningitidis serogroup B strain NMB contains L2, L3, and novel oligosaccharides, and lacks the lipid-A 4'-phosphate substituent.

The complete structure of the lipooligosaccharide (LOS) from Neisseria meningitidis strain NMB (serotype 2b:P1.2,5), a serogroup B cerebrospinal fluid isolate, was determined. Two oligosaccharide (OS) fractions and lipid-A were obtained following mild acid hydrolysis of the LOS. The structures in these fractions were determined using glycosyl composition and linkage analyses, N spectroscopy and mass spectrometry. One oligosaccharide fraction (OS1) consists of a molecule having a glycosyl sequence identical to that previously reported for the LOS from immunotype L2 N. meningitidis [A. Gamain, M. Beurret, F. Michon, J.-R. Brisson, and H.J. Jennings, J. Biol. Chem.,267,(112) 922-925] i.e., a lacto-N-neotetraose is attached to heptose I (Hep I), with terminally linked N-acetylglucosaminosyl and glucosyl residues attached to Hep II of the inner core. Approximately 70% of this structure is acetylated at O-6 of the terminally linked alpha-N-acetyl-glucosaminosyl residue. As with the L2 structure, the NMB LOS contained phosphoethanolamine (PEA) at O-6 or O-7 of the Hep II residue. The second oligosaccharide fraction (OS2) contains a a mixture of three different molecules, all of which vary from one another in their glycosyl substitution patterns of the Hep II residue. The most abundant molecule in OS2 has a structure identical to that of OSI, i.e., it has the L2 glycosyl sequence. A second molecule (OS2a) lacks the terminal glucosyl residue at O-3 of Hep II; i.e., it has a glycosyl sequence identical to that of the mild acid released oligosaccharide of N. meningitidis immunotype L3, L4, or L7 LOSs. The third molecule (OS2b) is a novel structure that lacks the terminal N-acetylglucosaminosyl residue linked to O-2 of Hep II. Overall, 76% of OS released from NMB LOS has the L2 structure, 15% is OS2a (L3), and 9% is OS2b. A portion (20%) of the molecules in the NMB LOS preparation also contained terminally linked sialic acid attached to O-3 of the lacto-N-neotetraose galactosyl residue, which is also consistent with the L3, or L4 LOS structures. In contrast to the previously reported structure of N. meningitidis lipid-A [V. A. Kulshin, U. Zähringer, B. Linder, C.E. Frasch, C-M. Tsai, B.A. Dmitriev, and E.T Rietschel, J. Bacteriol., 174, (1992)1793-1800], only 30% of the lipid-A from NMB LOS possesses 4'-phosphate. Comparison with the lipid-A of LOS purified from an isogenic acapsulate mutant, M7, revealed that the 4'-position was almost completely occupied with phosphate. These data emphasize the structural heterogeneity of the OS and phosphate substituents of Hep II, and 4'-phosphorylation of lipid-A of meningococcal LOS.

Carbohydrate Sequence↗
PubMed1998

Folic acid in the treatment of acute watery diarrhoea in children: a double-blind, randomized, controlled trial.

One-hundred and six male children aged 6-23 months with a history of acute watery diarrhoea of less than 72 h duration were randomized to receive either folic acid in a dose of 5 mg at 8-h intervals or placebo for 5 d. There were 54 children in the folic acid group and 52 in the placebo group. The admission characteristics were comparable between the two groups. No significant differences were observed in the intake of oral rehydration solution or stool output between the groups. The mean+/-SD of total stool output (g kg(-1)) was 532+/-476 vs 479+/-354 and the duration (h) of diarrhoea was 108+/-68 vs 103+/-53 in the folic acid vs placebo group, respectively. The findings, therefore, should have a positive influence on preventing the inappropriate use of folic acid in acute diarrhoea.

Acute Disease↗
PubMed1998

Increased height gain of children fed a high-protein diet during convalescence from shigellosis: a six-month follow-Up study.

The impact of dietary supplementation on catch-up growth was evaluated in 69 malnourished children ages 24-60 mo after recovery from shigellosis. They were fed either a high-protein (HP) diet with 15% of energy as protein, or a standard-protein (SP) diet with 7.5% energy as protein, for 3 wk in a metabolic study ward. Children were followed up bi-weekly for 6 mo by trained health assistants when anthropometric measurements and information of any illness were collected. Thirty-one children in the HP group and 28 children in the SP group completed 6-mo follow-up. The increase in height (mean +/- SD) was 5.3 +/- 1.0 cm vs. 4.1 +/- 1.1 cm for HP and SP groups, respectively (P < 0.001), whereas increase in body weight was 1.39 +/- 0.58 and 1.29 +/- 0.72 kg for children fed HP and SP, respectively (P = 0.59). The proportion of children who were severely stunted (< -2 SD height-for-age) decreased from 45 to 29% in the HP group compared to 50 to 46% in the SP group (P < 0.05) at 6-mo follow-up. The number of diarrheal episodes per child tended to be lower in the HP vs. SP than in the SP group (1.9 vs. 2.3, P = 0.41). These results demonstrate that feeding an HP diet to the malnourished children during recovery from shigellosis enhanced linear growth with a modest reduction in diarrheal morbidity during the 6-mo follow-up period.

Amdinocillin Pivoxil↗
PubMed1998

Helicobacter pylori colonization in infants and young children is not necessarily associated with diarrhoea.

A cohort of 151 infants and young children aged 1-23 months from a poor peri-urban community of Bangladesh was studied to determine the relationship between Helicobacter pylori colonization and morbidity due to diarrhoea. A 13C urea breath test was performed to detect the presence of H. pylori. Children were followed up at home every alternate day for 6 months and diarrhoeal morbidity data were collected. Diarrhoeal morbidity was compared between H. pylori-positive and H. pylori-negative children. Sixty-eight (45 per cent) children were H. pylori positive and 83 (55 per cent) were H. pylori negative. During the first 1-month period following the breath test, three (4.4 per cent) H. pylori-positive and four (4.8 per cent) H. pylori-negative children had diarrhoea. Thirty-two (47 per cent) of the children in the positive group and 43 (52 per cent) in the negative group had one or more episodes of diarrhoea during the 6-month follow-up period. Median number of diarrhoeal episodes was 1.0 (range 1.0-4.0) in the H. pylori-positive children and 2.0 (range 1.0-5.0) in the H. pylori-negative children (p = 0.19). No significant difference was observed in the cumulative days with diarrhoea. The results of this study suggest that H. pylori colonization is not associated with diarrhoeal morbidity in infants and young children.

Bangladesh↗
PubMed1998

The (alpha2-->8)-linked polysialic acid capsule and lipooligosaccharide structure both contribute to the ability of serogroup B Neisseria meningitidis to resist the bactericidal activity of normal human serum.

The molecular basis for the resistance of serogroup B Neisseria meningitidis to the bactericidal activity of normal human sera (NHS) was examined with a NHS-resistant, invasive serogroup B meningococcal isolate and genetically and structurally defined capsule-, lipooligosaccharide (LOS)-, and sialylation-altered mutants of the wild-type strain. Expression of the (alpha2-->8)-linked polysialic acid serogroup B capsule was essential for meningococcal resistance to NHS. The very NHS-sensitive phenotype of acapsular mutants (99.9 to 100% killed in 10, 25, and 50% NHS) was not rescued by complete LOS sialylation or changes in LOS structure. However, expression of the capsule was necessary but not sufficient for a fully NHS-resistant phenotype. In an encapsulated background, loss of LOS sialylation by interrupting the alpha2,3 sialyltransferase gene, lst, increased sensitivity to 50% NHS. In contrast, replacement of the lacto-N-neotetraose alpha-chain (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) with glucose extensions (GlcN) in a galE mutant resulted in a strain resistant to killing by 50% NHS at all time points. Encapsulated meningococci expressing a Hep2(GlcNAc)-->KDO2-->lipid A LOS without an alpha-chain demonstrated enhanced sensitivity to 50% NHS (98% killed at 30 min) mediated through the antibody-dependent classical complement pathway. Encapsulated LOS mutants expressing truncated Hep2-->KDO2-->lipid A and KDO2-->lipid A structures were also sensitive to 50% NHS (98 to 100% killed at 30 min) but, unlike the wild-type strain and mutants with larger oligosaccharide structures, they were killed by hypogammaglobulinemic sera. These data indicate that encapsulation is essential but that the LOS structure contributes to the ability of serogroup B N. meningitidis to resist the bactericidal activity of NHS.

Bacterial Capsules↗
PubMed1998

Detection of Shigellae from stools of dysentery patients by culture and polymerase chain reaction techniques.

In Bangladesh, the isolation rates of Shigella spp. range from 11% to 12% by the conventional culture technique. Since the sensitivity of this technique is low, the polymerase chain reaction (PCR) technique was used for detecting small number of Shigellae from patients' stools. Sensitivity and specificity of the two techniques were also compared. Stool samples were collected from 41 patients with dysentery who attended the Clinical Research and Service Centre of the ICDDR,B: Centre for Health and Population Research. All stool specimens were directly plated onto MacConkey, Salmonella-Shigella, Xylose lysin deoxycholate and Hectoen enteric agar media, and Shigellae were detected following standard procedures. DNA was extracted from the stool samples, and the target sequence of invasive plasmid antigen (ipa)H locus was amplified by PCR with 130 ng each of two primers (primer H8 [5'-GTTCCTTGACCGCCTTTCCGATAC-3'] and primer H15 [5'-GCCGGTCAGCCACCCTA-3']) following standard procedures. The amplified product was hybridized using an ipaH probe. The isolation rates of Shigella dysenteriae type 1, S. flexneri, S. sonnei, and S. boydii were, respectively, 17.1%, 19.5%, 4.9% and 2.4% by the conventional method. The results of the PCR technique showed that 700 bp fragment was generated in 18 of the 18 culture-positive and in 7 of the 23 culture-negative stools. One hundred twenty-three strains of Escherichia coli were also tested by PCR for identifying the enteroinvasive E. coli, but none of them yielded any positive result. This study showed that the sensitivity of the culture technique is 72% and specificity is 100%, when the PCR technique was considered as gold standard. Therefore, the PCR may be considered a more sensitive and specific technique than the conventional culture technique and has the potential to be employed in routine diagnosis of dysentery in clinical centres as well as in epidemiologic studies.

Bacteriological Techniques↗
PubMed1997

The structure of the capsular polysaccharide from a swarming strain of pathogenic Proteus vulgaris.

The structure was determined for the capsular polysaccharide (CPS) isolated from a swarming strain of Proteus vulgaris, CP2-96, which was obtained from the spleen of an infected mouse. The CPS was extracted from the cell pellet by hot water, precipitated with ethanol, and further purified by gel-permeation chromatography. The structure was established by glycosyl composition and linkage analyses, and by NMR spectroscopy. The sequence of the glycosyl residues was determined by a NOESY experiment. The CPS is composed of a tetrasaccharide repeating unit with the following structure: OAc [symbol: see text] 4 -->4)-beta-D-Glcp-(1-->3)-beta-D-GalpNAc-(1-->2)-alpha-D-Glcp-(1-->4)-al pha- D-GlcpA-(1-->.

Animals↗
PubMed1997

Characterization of a mutant of Vibrio vulnificus for heme utilization.

Vibrio vulnificus, an opportunistic human pathogen, can obtain iron from a variety of heme proteins. This process involves the digestion of heme proteins by an exoprotease to liberate protoheme (iron-protoporphyrin IX). In the present study, we isolated and characterized a mutant for protoheme utilization. One mutant isolated by treatment with a chemical mutagen was shown to be unable to use either protoheme or heme proteins, but multiplied in a medium supplemented with an iron siderophore, such as iron-vulnibactin. Like a wild-type strain, the mutant sensed iron depletion, so that the 74- and 79-kDa outer membrane proteins were expressed under iron-regulated conditions. Both the parent and mutant strains secreted hemolysin independent of the iron concentration of the medium. Whole cells of either of the strains were equally capable of binding of hematin. Taken together, the data suggest that the mutant may have a mutation in a gene encoding an inner membrane or a periplasmic protein which transports protoheme or iron dissociated from protoporphyrin IX into the cell.

DNA, Bacterial↗
PubMed1997

Expression and localization of annexin V and annexin VI during limb bud formation in the rat fetus.

We have investigated the expression and the localization of annexin V and annexin VI during the development of rat fetal limb buds by immunoblot and immunocytochemical analysis. Neither annexin V nor annexin VI was detectable in undifferentiated mesenchymal cells in limb buds of the day-13-day-16 rat fetus. Skeletal muscles, whose progenitor cells migrate from the somites and appeared in the limb buds at day 14, dramatically expressed annexin VI on the cell surface after differentiation from mononucleated myogenic cells into multinucleated myotubes. At day 16 both annexin V and annexin VI were found to be expressed in differentiated chondrocytes as well as in the perichondrium, a precursor of chondrocytes, whereas the compact layer of mesenchymal cells surrounding a chondrification center (precartilage) did not show any immunoreactivity for either of these proteins. The results suggest a close relationship between the expression of these annexins and cell differentiation of chondrocytes and skeletal muscles during limb but development.

Animals↗