Biomedical subjects

F Rahman

Publications and source records attributed to F Rahman.

At least 19 recordsLinked to original sources

PubMed2006

Angular distributions of H-induced HD and D2 desorptions from the Si(100) surfaces.

We measured angular distributions of HD and D2 molecules desorbed via the reactions H+DSi(100)-->HD [abstraction (ABS)] and H+DSi(100)-->D2 [adsorption-induced-desorption (AID)], respectively. It was found that the angular distribution of HD molecules desorbed along ABS is broader than that of D2 molecules desorbed along AID, i.e., the former could be fit with cos(2.0+/-0.2) theta, while the latter with cos(5.0+/-0.5) theta. This difference of the angular distributions between the two reaction paths suggests that their dynamic mechanisms are different. The observed cos2 theta distribution for the ABS reaction was reproduced by the classical trajectory calculations over the London-Eyring-Polanyi-Sato potential-energy surfaces. The simulation suggests that the HD desorption along the ABS path takes place along the direction of Si-D bonds, but the apparent angular distribution is comprised of multiple components reflecting the different orientations of D-occupied Si dimers in the (2 x 1) and (1 x 2) double domain structures.

Journal Article↗

PubMed2006

Drowning--a major but neglected child health problem in rural Bangladesh: implications for low income countries.

This study was intended to estimate the magnitude and explore the determinants of childhood drowning in rural Bangladesh. A cross-sectional survey as well as a population-based case - control study was conducted. By multistage cluster sampling 51 147 children aged 1 - 4 years were identified from 108 827 rural households. All drownings in children aged 1 - 4 years in the preceding 5 years were identified and recruited as cases and two living children of the same age group were selected from the same localities as controls. Socio-economic, demographic, environmental and other related information was collected from mothers of both cases and controls by face-to-face interview with the help of structured questionnaires. The incidence of drowning among children aged 1 - 4 years old was 156.4 per 100 000 children-year. The highest rate (328.1 per 100 000; 95% CI 254.8 - 421.7) was observed in 1 year old male children. The proportional mortality due to drowning in the children was 27.9%. Mothers' age and literacy and family income were identified as risk factors. Drowning is one of the major causes of 1 - 4 years childhood mortality in Bangladesh. One-year-old male children from poor families were at great risk of drowning in rural Bangladesh.

Age Distribution↗

PubMed2006

Comprehensive findings on clinical, bacteriological, histopathological and therapeutic aspects of cutaneous tuberculosis.

OBJECTIVE: To define the bacteriological and histological correlates of the three predominant clinical forms of cutaneous tuberculosis and to evaluate the efficacy of a 9-month daily regimen containing rifampicin and isoniazid. METHODS: In the dermatological clinics of two major teaching hospitals in Chennai, 213 patients with suspected clinical manifestations of cutaneous tuberculosis underwent examination and a skin biopsy for bacteriological and histological tests. They were treated with a daily regimen of rifampicin and isoniazid for 9 months and follow-up for 3 years. RESULTS: Bacteriological and/or histological confirmation of tuberculosis was obtained in 88% of the cases. Lupus vulgaris lesions were seen mainly in the extremities and verrucosa cutis occurred predominantly on the sole and foot, while the cervical and axillary regions were the commonest sites for scrofuloderma. Ninety-two per cent of the patients showed resolution of the lesions within the first 6 months of chemotherapy; 1% failed to respond to this regimen. There was no relapse in any of the cases during the follow-up period of 3 years. CONCLUSIONS: Clinical findings were adequate to identify major forms of cutaneous tuberculosis as evidenced by bacteriological and histopathological examination. A daily regimen of rifampicin and isoniazid for 9 months was effective in treating cutaneous tuberculosis.

Adult↗

PubMed2005

In vitro activity of fluoroquinolones against Mycobacterium tuberculosis.

The in vitro activity of fluoroquinolones, including lomefloxacin, ofloxacin, ciprofloxacin, sparfloxacin, moxifloxacin and gatifloxacin, was evaluated against 55 clinical isolates of Mycobacterium tuberculosis by absolute concentration method on Lowenstein-Jensen (L-J) and Middlebrook's 7H11 media. Both ofloxacin susceptible and ofloxacin resistant strains of M. tuberculosis isolates were tested. The in vitro activities of these fluoroquinolones on the M. tuberculosis isolates were in the order: lomefloxacin < ciprofloxacin < or = ofloxacin < sparfloxacin < moxifloxacin = gatifloxacin. Gatifloxacin and moxifloxacin showed low minimal inhibitory concentrations (MIC) for both ofloxacin resistant and ofloxacin susceptible strains even though some cross resistances were observed.

Aza Compounds↗

PubMed2005

Asthma, atopic eczema and allergic rhino-conjunctivitis in school children.

International Study of Asthma and Allergies of Childhood (ISAAC) phase one study had already been completed in two age groups in 156 collaborating centers of 56 countries involving a total of 721601 children. Bangladesh did not participate earlier in this worldwide study. To determine the prevalence of asthma, allergic rhinitis and eczema in school children of Dhaka district using ISAAC protocol. A school based cross sectional study done in 2000 by using both written questionnaires (WQ) and video questionnaires (VQ). Students of class-VIII (13-14 years) filled up both the WQ and VQ and the parents of class I (6-7 years) filled up only the WQ on behalf of the students. Sixty five (6)5 primary schools and 39 high schools were randomly selected from all 19 thanas to cover equally both the urban and rural schools of the entire area of Dhaka district. A total of 6260 written questionnaires were eligible for the analysis (3029 form 6-7 years of class I and 3231 from 13-14 years of class VIII). In addition, the validated international video questionnaires were used for the older age group (3231). The symptoms of atopic diseases in the previous 12 months or ever in all children, both age groups, both sexes and in both urban and rural areas. The life time (ever) and 12-month period (recent) prevalence of three allergic conditions with 95% CI were as follows : wheezing 13.8% (12.9-14.6), 7.6% (6.9-8.2); allergic rhinitis 25.0% (23.9-26.1), 20.0% (19.1-21.1) and eczema 8.7% (CI 8.0-9.4), 6.5% (5.9-7.2). respectively. The prevalence of wheezing and other atopic features in both age groups of 6-7 years and 13-14 years showed higher features of recent wheeze in the younger children than in the older children, recent wheeze 9.1% Vs 6.1%; but the other atopic features were found lower in younger age group, recent rhinitis 16.3% Vs 23.5%, 0.001; conjunctivitis 6.4% Vs 8.3%, 0.001; recent eczema 6.0% Vs 7.1% 0.001. Male children were found to be more suffering from all types allergic conditions than their female peers: recent wheeze 9.0% Vs 5.9%, recent rhinitis 21.9% Vs 17.9%, recent allergic conjunctivitis 8.7% Vs 6.7% and recent eczema 6.8% Vs 6.2%). Though the prevalence of asthma and atopic eczema was lower than those of developed countries but still appeared to be a major health problem for our children. Allergic rhinitis was the commonest of all atopic problems in children. The younger children (6-7 years) were more likely to suffer from wheeze (asthma) but other allergic problems were more in older group of children (13-14 years). Male children were more prone to all types of allergic problems, whether wheeze or other atopic conditions, than the female peers.

Adolescent↗

PubMed2005

Comparison of variants of carbol-fuchsin solution in Ziehl-Neelsen for detection of acid-fast bacilli.

To evaluate Ziehl-Neelsen (ZN) staining using variants of carbol-fuchsin solution, duplicate smears from 416 samples were stained with ZN, one set with 1% basic fuchsin and the other 0.3%. Another set of duplicate smears from 398 samples were stained with ZN, one with 1% basic fuchsin and the other 0.1%. The coded smears were read and discrepancies resolved. All samples underwent mycobacterial culture. The sensitivity of ZN using 0.3% (65%) and 1% basic fuchsin (62%) was comparable, while it was reduced using 0.1% (74%) compared to 1% basic fuchsin (83%). Reducing the concentration of basic fuchsin below 0.3% in ZN staining was found to significantly reduce its sensitivity.

Coloring Agents↗

PubMed2004

Modulated hydrogen beam study of adsorption-induced desorption of deuterium from Si(100)-3x1:D surfaces.

We have studied the kinetic mechanism of the adsorption-induced-desorption (AID) reaction, H+D/Si(100) --> D2. Using a modulated atomic hydrogen beam, two different types of AID reaction are revealed: one is the fast AID reaction occurring only at the beam on-cycles and the other the slow AID reaction occurring even at the beam off-cycles. Both the fast and slow AID reactions show the different dependence on surface temperature Ts, suggesting that their kinetic mechanisms are different. The fast AID reaction overwhelms the slow one in the desorption yield for 300 K < or = Ts < or = 650 K. It proceeds along a first-order kinetics with respect to the incident H flux. Based on the experimental results, both two AID reactions are suggested to occur only on the 3x1 dihydride phase accumulated during surface exposure to H atoms. Possible mechanisms for the AID reactions are discussed.

Journal Article↗

PubMed2003

Quality assurance studies in eight State tuberculosis laboratories in India.

SETTING: Tuberculosis Research Centre, Chennai, India. OBJECTIVE: To undertake quality assurance studies in sputum smear microscopy at eight State-level laboratories in India using a panel of stained smears. DESIGN: Coded panels of stained smears (100 slides in rounds I-IV and 50 slides in Round V), comprising different grades of positivity, were sent to each centre at 6-monthly intervals. The results obtained were analysed for consistency of positive and negative results and overall agreement, as well as discordance. RESULTS: Consistency of positives ranged from 38% to 100%, indicating under-reading at some sites. The negative consistency was better, however, with only five of the total of 95 readers in all rounds yielding a consistency of less than 100%. Considering overall agreement, seven of the eight centres showed an agreement of over 90%. Four of the eight centres gave no false-positive result. For the remaining centres the false positivity rate varied from 2% to 7%. A wide variation was also observed in the proportion of false-negatives (3%-52%). CONCLUSIONS: This study helped in the evaluation of the performance of individual laboratories and in identifying the drawbacks of this system of proficiency testing.

Clinical Competence↗

PubMed2003

Cefaclor AF vs Clarithromycin in acute exacerbation of chronic bronchitis (B3M-PK-AJBG).

OBJECTIVE: To compare the efficacy and safety of Cefaclor AF vs Clarithromycin in the treatment of acute exacerbation of chronic bronchitis in adult subjects. PATIENTS AND METHODS: This study was conducted on 300 patients suffering from acute exacerbation of chronic bronchitis, who attended the out patient clinics of ten different hospitals throughout Pakistan. Pneumonia, bronchiectasis and tuberculosis were excluded with the help of chest radiography and sputum smear examination. Pretherapy sputum culture and sensitivity (c/s) were tested and patients were randomized and supplied with either tablet Cefaclor 375 mg or tablet Clarithromycin 250 mg to be taken twice daily. Patients were evaluated at day 0 and then at day 3-5 and day 10-11. Post therapy sputum c/s was done on day 10-11. A fourth and final visit was planned on day 20-24 which was optional. At each visit, the severity of disease and the signs and symptoms were recorded on the clinical report forms according to the preset standards. RESULTS: Of 136 patients in the Cefaclor group and 142 patients in the Clarithromycin group, cure was achieved in 44 vs 35 subjects, improvement in 78 vs 91 subjects and failure in 16 vs 18 subjects among Cefaclor vs Clarithromycin groups respectively. The overall clinical efficacy (cure and improvement combined ) was 88.4% in the Cefaclor group and 87.5% in the Clarithromycin group. Nine patients in the Cefaclor group and patients in the Clarithromycin group had one adverse event whereas twelve patients in each group had two or more adverse events. CONCLUSIONS: The above results show that both Cefaclor AF and Clarithromycin are equally effective and safe in the treatment of acute exacerbation of chronic bronchitis in adult patients.

Acute Disease↗

PubMed2003

Blinded rechecking of sputum smears for acid-fast bacilli to ensure the quality and usefulness of restaining smears to assess false-positive errors.

SETTING: Microscopy Centres, Velliyur Tuberculosis Unit, Tiruvallur District, Tamil Nadu, India. PROCEDURES: Twelve microscopy centre laboratory technicians examined 41978 direct sputum smears for acid-fast bacilli. Senior Tuberculosis Laboratory Supervisors (STLS) checked all positive smears (4696) and 10% of negative smears (4776) in an unblinded fashion as per Revised National Tuberculosis Control Programme (RNTCP) guidelines. Ten per cent of the positive and negative slides and another 10% of unchecked negative slides were selected systematically for blinded rereading at the Tuberculosis Research Centre (TRC); 422 slides were reread without and with restaining. RESULTS: Unblinded checking by STLS of the smears read by the laboratory technicians yielded 95 to 100% agreement. Blinded rereading at the TRC revealed that false-negative errors were greater among the laboratory technicians (2-7%) than the STLS (0-3%). Restaining and blinded rereading of slides reduced false-positive errors from 27% to 7%. CONCLUSIONS: Blinded rereading at the reference centre facilitates assessment of laboratory technicians and STLS. Restaining before rereading the smears was found to be useful for precise estimation of false-positive errors.

Coloring Agents↗

PubMed2003

Evaluation of neuropharmacological effects of Rumex maritimus Linn. (Polygonaceae) root extracts.

Hexane, ethyl acetate and methanol extracts of the root of Rumex maritimus Linn. (Polygonaceae) were evaluated for neuropharmacological activities in different models. All the extracts significantly and dose dependently inhibited acetic acid induced abdominal constrictions in mice. The hexane and methanol extract exhibited significant central analgesic activity in the radiant heat method. Only the methanol extract showed statistically significant mild to moderate central nervous system depressant activity assessed by hole cross, open field and hole board test in the mice model.

Acetic Acid↗

PubMed2002

Private pharmacies in tuberculosis control--a neglected link.

In most settings in India, private pharmacies dispense prescriptions for anti-tuberculosis drugs made out by private practitioners. In a cross-sectional study, we assessed the dispensing practices for tuberculosis and knowledge about the national tuberculosis programme of 300 pharmacies. In all, 2800 prescriptions were dispensed monthly by the pharmacies. Doctors' prescriptions were for durations of several months, but half of the patients bought drugs one dose at a time for self-administration. This practice might promote drug resistance. Although 95% of pharmacists were not aware of the existence of the tuberculosis programme, the majority (97%) were willing to learn and contribute towards tuberculosis control. The need and the potential of private pharmacies for participation in tuberculosis control are highlighted.

Antitubercular Agents↗

PubMed2002

Effectiveness of baby friendly hospital initiative on the promotion of exclusive breast feeding among the Dhaka city dwellers in Bangladesh.

To assess the effectiveness of baby friendly hospital initiative on exclusive breast feeding status; this longitudinal study designed to compare the incidence of exclusive breast feeding at 30, 60, 90, 120 and 150 days post partum for mothers who delivered at baby friendly hospital and mothers who delivered at a nearby non-baby friendly hospital. 105 mothers from baby friendly hospital and 104 mothers from non-baby friendly hospital were recruited and followed up for determining duration of exclusive breast-feeding. The median survival time of exclusive breast-feeding was 73.85 days among mothers of baby friendly hospital and 30 days among mothers of non-baby friendly hospital, with a difference of 43.85 days. Life table cumulative surviving proportion for exclusive breast-feeding shows that 82 percent mothers of baby friendly hospital continue at 30 days, compared with 50 percent mothers off non-baby friendly hospital. At 150 days, 16 percent mothers of baby friendly hospital continue exclusive breast-feeding compared with 6 percent mothers of non-baby friendly hospital. Finally 8 percent mothers of baby friendly hospital continue exclusive breast feeding between two hospital was found highly significant (P < 0.001). Duration of exclusive breast-feeding is longer among the mothers who have been delivered in a baby friendly hospital than those mothers who have been delivered in a non-baby friendly hospital.

Adolescent↗

PubMed2001

Polybrominated diphenyl ether (PBDE) flame retardants.

Polybrominated diphenyl ether, PBDE, flame retardants are now a world-wide pollution problem reaching even remote areas. They have been found to bioaccumulate and there are concerns over the health effects of exposure to PBDEs, they also have potential endocrine disrupting properties. They are lipophilic compounds so are easily removed from the aqueous environment and are predicted to sorb onto sediments and particulate matter or to fatty tissue, aiding their distribution throughout the environment. PBDEs are structurally similar to PCBs and DDT and, therefore, their chemical properties, persistence and distribution in the environment follow similar patterns. Concentrations of PBDEs found in environmental samples are now higher than those of PCBs. Evidence to date demonstrates that PBDEs are a growing problem in the environment and concern over their fate and effects is warranted. The manufacture of reactive and additive flame retardants is briefly discussed and their fate and behaviour in the environment is assessed. PBDE toxicology is reviewed and methods of analysis are evaluated.

Animals↗

PubMed2001

Serial evaluation of serum neopterin in HIV seronegative patients treated for tuberculosis.

OBJECTIVE: To delineate the course of serum neopterin (s-neo) concentrations in patients with pulmonary tuberculosis who are on anti-tuberculosis therapy. DESIGN: S-neo concentrations were measured by high performance liquid chromatography (HPLC) in 39 patients treated for pulmonary tuberculosis at pretreatment, at one month and at end of treatment. It was also measured in 11 relapse cases and their matched controls at the above time points and at the time of relapse. The results were correlated with bacteriological and radiological findings. RESULTS: All patients had elevated levels of s-neo at pretreatment which had declined at 1 month and were near normal at the end of treatment. The decline was more significant in patients with moderate lesions, suggesting that immune activation is maximum in this group of patients. The mean decrease was 37% at one month and 66% at the end of treatment. The corresponding decreases were 11% and 56% in patients with limited lesions and 11% and 45% in those with extensive lesions. It continued to fall after completion of therapy in patients who did not relapse, whereas an increase after completion of therapy was associated with bacteriologically proven relapse. CONCLUSIONS: The measurement of s-neo concentration could be of help in evaluating response to therapy. This study provides a rational basis for the association between s-neo concentration and relapse.

Adult↗

PubMed2001

Comparison of different methods of assessing in vitro resistance of Mycobacterium tuberculosis to rifampicin.

BACKGROUND & OBJECTIVES: Definitions of in vitro resistance to rifampicin in strains of Mycobacterium tuberculosis by different methods have not been consistent, leading to variations in the interpretation and validity of results. This study compared three methods of defining in vitro resistance to rifampicin. METHODS: (i) A total of 598 clinical isolates of M. tuberculosis were concurrently compared by the minimal inhibitory concentration (MIC) and the proportion method on Lowenstein-Jensen medium; (ii) 54 strains tested by the MIC method were retested by the proportion method and the BACTEC radiometric method; and (iii) 72 strains which yielded an MIC of 64 mg/l by the MIC method were retested by the same method. RESULTS: Out of 598 cultures tested by the MIC and the proportion methods, identical classification as susceptible or resistant was observed in 99.7 per cent. A 100 per cent agreement was observed when 54 strains were tested by the MIC, proportion and BACTEC radiometric methods. When 72 strains with an MIC of 64 mg/l were retested by the same method, 61 (85%) yielded a lower MIC, 9 (12%) gave the same MIC while 2 (3%) yielded a higher MIC of 128 mg/l, reflecting perhaps the inherent limitations of the variations in the inoculum size. INTERPRETATION & CONCLUSION: All 3 definitions of resistance, viz., an MIC of 128 mg/l, a proportion of 1 per cent or more on 40 mg/l by the proportion method, both on L-J medium and a growth of 1 per cent or more on 2 mg/l by the radiometric method were found to be equally satisfactory.

Antibiotics, Antitubercular↗

PubMed2000

A dynamically tuned double-stranded RNA binding mechanism for the activation of antiviral kinase PKR.

A key step in the activation of interferon-inducible antiviral kinase PKR involves differential binding of viral double-stranded RNA (dsRNA) to its two structurally similar N-terminal dsRNA binding motifs, dsRBM1 and dsRBM2. We show here, using NMR spectroscopy, that dsRBM1 with higher RNA binding activity exhibits significant motional flexibility on a millisecond timescale as compared with dsRBM2 with lower RNA binding activity. We further show that dsRBM2, but not dsRBM1, specifically interacts with the C-terminal kinase domain. These results suggest a dynamically tuned dsRNA binding mechanism for PKR activation, where motionally more flexible dsRBM1 anchors to dsRNA, thereby inducing a cooperative RNA binding for dsRBM2 to expose the kinase domain.

Amino Acid Sequence↗

PubMed2000

Noninvasive diagnosis by Doppler ultrasonography of fetal anemia due to maternal red-cell alloimmunization. Collaborative Group for Doppler Assessment of the Blood Velocity in Anemic Fetuses.

BACKGROUND: Invasive techniques such as amniocentesis and cordocentesis are used for diagnosis and treatment in fetuses at risk for anemia due to maternal red-cell alloimmunization. The purpose of our study was to determine the value of noninvasive measurements of the velocity of blood flow in the fetal middle cerebral artery for the diagnosis of fetal anemia. METHODS: We measured the hemoglobin concentration in blood obtained by cordocentesis and also the peak velocity of systolic blood flow in the middle cerebral artery in 111 fetuses at risk for anemia due to maternal red-cell alloimmunization. Peak systolic velocity was measured by Doppler velocimetry. To identify the fetuses with anemia, the hemoglobin values of those at risk were compared with the values in 265 normal fetuses. RESULTS: Fetal hemoglobin concentrations increased with increasing gestational age in the 265 normal fetuses. Among the 111 fetuses at risk for anemia, 41 fetuses did not have anemia; 35 had mild anemia; 4 had moderate anemia; and 31, including 12 with hydrops, had severe anemia. The sensitivity of an increased peak velocity of systolic blood flow in the middle cerebral artery for the prediction of moderate or severe anemia was 100 percent either in the presence or in the absence of hydrops (95 percent confidence interval, 86 to 100 percent for the 23 fetuses without hydrops), with a false positive rate of 12 percent. CONCLUSIONS: In fetuses without hydrops that are at risk because of maternal red-cell alloimmunization, moderate and severe anemia can be detected noninvasively by Doppler ultrasonography on the basis of an increase in the peak velocity of systolic blood flow in the middle cerebral artery.

Blood Flow Velocity↗