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Biomedical subjects

M U Khan

Publications and source records attributed to M U Khan.

At least 37 records · Page 2Linked to original sources
PubMed1988

The Effect of Temperature on the Level and Biosynthesis of Unsaturated Fatty Acids in Diacylglycerols of Brassica napus Leaves.

Experiments on the effects of temperature on the levels of unsaturated fatty acids and their rates of desaturation in Brassica napus leaf lipids have shown that significant differences occur in the composition of all diacylglycerols in the leaf between plants grown at high and low temperatures. In the major thylakoid diacylglycerols, monogalactosyl-diacylglycerol and digalactosyldiacylglycerol, not only is there an increase in the level of unsaturation at low temperatures, but there is a change in the balance between molecular species of chloroplastic origin (16/18C) and cytosolic origin (18/18C). Radioactivity tracer data indicate that at low temperatures there are two distinct phases of desaturation in the fatty acids of the major diacylglycerols of these leaves. A rapid phase, which appears in plants grown at low temperatures and results in the desaturation of palmitic acid to hexadecadienoic acid and oleic acid to linoleic acid may explain the high levels of unsaturated fatty acids found in the leaf diacylglycerols from plants grown at low temperatures. The appearance of this rapid phase is controlled by the temperature at which the plant is grown and is not subject to rapid variations in environmental temperature.

Journal Article↗
PubMed1987

Limitation of communal latrines in changing the prevalence of parasites and diarrhoeal attack rate in Dhaka Peri-urban slums.

A study of the effects of communal latrines on diarrhoeal incidence and parasite prevalence rates was conducted in 1983 at Tongi, which had five communal Oxfam latrines with a manual flushing system for 924 people; and at Kalsi, which had 39 open fit latrines for 823 people. Inhabitants' stool samples were tested initially and also after twelve months to see the reinfection rates. All inhabitants were dewormed with pyrantel, and were visited weekly to obtain diarrhoea histories. In both communities, there were high prevalence rates of roundworm, hookworm, Trichuris trichiura, Entamoeba histolytica, Giardia lambia and Strongyloides stercoralis. Following the dewormings, the prevalence rates of roundworm, hookworm and Trichuris infection came down significantly, in both areas. The prevalence or reinfection rates remained identical in both communities. There was also no difference in diarrhoea incidence rate for the two areas. It is found that keeping all other variables unchanged, use of communal latrines, without strict disposal of everyone's excreta, does not affect parasite prevalence and diarrhoea rates. People must be educated about the use of communal latrines and the safe disposal of all excreta, including that of children.

Journal Article↗
PubMed1987

B subunit-whole cell and whole cell-only oral vaccines against cholera: studies on reactogenicity and immunogenicity.

We conducted a randomized trial among persons in rural Bangladesh to evaluate the side effects and immunogenicity of orally administered B subunit-killed whole cell (BS-WC) and killed whole cell-only (WC) cholera vaccines and a killed Escherichia coli strain K12 placebo proposed for field testing. Three doses of BS-WC, WC, E. coli, or a control agent were given with antacid to 1,257 women (aged greater than 15 years) and children (aged to to 15 years). The four groups exhibited no statistically significant differences in occurrence of symptoms after each dose, and rises in titers of vibriocidal (VC) antibodies to Inaba and Ogawa were twofold higher for vaccinees than for controls (P less than .001). Half of the persons with fourfold or greater VC responses to WC responded after the first dose; many additional patients, particularly young children, responded after subsequent doses. In contrast, 89% of persons who responded to BS-WC with twofold or greater rises in titer of IgG antibodies to cholera toxin did so after the first dose. After the third dose, vaccinees exhibited a fivefold higher rise in titer than did controls (P less than .001); a dose-to-dose booster effect was most evident in young children.

Administration, Oral↗
PubMed1987

Vibriocidal titre in cholera cases and contacts: its value in assessing endemicity of or susceptibility to cholera.

Vibriocidal antibody titre in excess of 1:40 occurred within two weeks of cholera infection, both in severe hospitalized cases, contact cases and in asymptomatic infected contacts. These levels, considered to be indicative of protection, persisted for six months or longer in more than half of the subjects irrespective of presence and severity of symptoms. Approximately 40% of infected family contacts had similar titres implying recent infection and subsequent protection. The use of antibiotics to treat acute cases, and whether infection was due to antibiotic resistant or sensitive Vibrio cholerae had no effect on the response of vibriocidal titre. Endemicity of cholera was higher than previously observed in Dhaka. Screening populations to obtain positive titre rates permits retrospective assessment of cholera infection and provides an indicator of future susceptibility.

Acute Disease↗
PubMed1986

Field trial of oral cholera vaccines in Bangladesh.

The protective efficacy of oral B subunit killed whole-cell (BS-WC) and killed whole-cell (WC) cholera vaccines was assessed in 63 498 Bangladeshi children aged 2-15 years and women aged over 15 years. Each received three doses of BS-WC, WC, or placebo in a randomised, double-blinded fashion. Surveillance for cases seeking medical care up to six months after the third dose revealed 26 cases of confirmed cholera in the placebo group, 4 cases in the BS-WC group (protective efficacy 85%; p less than 0.0001), and 11 cases in the WC group (protective efficacy 58%; p less than 0.01). For each vaccine protective efficacy was consistent in different age-groups (2-10 years versus greater than 10 years) and for different severities of cholera.

Administration, Oral↗
PubMed1986

Epidemiological differences between cholera due to multiple antibiotic resistant and multiple antibiotic sensitive Vibrio cholerae infection.

The appearance of cholera caused by multiply antibiotic resistant Vibrio cholerae in Bangladesh provided an opportunity to compare epidemiological features of infection caused by resistant and by sensitive V. cholerae. A prospective study was carried out using 46 families of hospital in-patient cholera cases due to resistant V. cholerae and 11 families of hospital cases due to sensitive V. cholerae and nine cases of cholera due to resistant and six cases due to sensitive V. cholerae detected in the neighbourhoods of hospital patients. All families were visited daily during ten days for cultures of rectal swabs, samples of domestic water and for history of diarrhoea. The results showed no significant difference in secondary infection and case rates in contacts of hospital cholera cases due to resistant and sensitive V. cholerae. However, the secondary infection rate (57%) in contacts of cases due to resistant V. cholerae detected from the neighbourhoods of hospital cases was significantly higher (p less than 0.05), than in the neighbourhood case-contacts (29%) of cases due to sensitive V. cholerae. The mean duration of diarrhoea in untreated resistant V. cholerae cases who were contacts of hospital cases (3.3 days) was significantly longer (p less than 0.05) than that of untreated sensitive V. cholerae (2.2 days). Higher isolation rates of V. cholerae were obtained from water sources used by cholera cases due to resistant V. cholerae, than from sources used by cases due to sensitive V. cholerae, but the differences were not statistically significant (p greater than 0.05). The study suggests that resistant V. cholerae poses an additional threat through a higher secondary infection rate and by causing illnesses of longer duration.

Anti-Bacterial Agents↗
PubMed1986

Risk factors for diarrhoeal deaths: a case-control study at a diarrhoeal disease hospital in Bangladesh.

The study of diarrhoeal mortality risk has been limited to descriptive epidemiological investigations. This is the first case-control study in this area, and our results show that certain risk factors are predictive of diarrhoeal deaths. We have compared the disease history, associated complications, signs, symptoms and laboratory values of 346 patients who died on the medical wards of Dhaka Hospital and that for 346 matched controls to identify the risk factors for mortality. Patients presenting with oedema, severe dehydration or convulsion were found to have a risk of mortality two times higher than controls. Several laboratory results were compared by a matched pair analysis, demonstrating that hyponatraemia (less than 130 mmol/L), hypobicarbonaemia (less than 20 mmol/L) and raised anion gap (greater than 14.9 mmol/L) were moderately associated with mortality. However, hypoproteinaemia (less than 50 gm/L) was strongly associated. For children less than 10 years of age, both hyper- and hyponatraemia were found to be associated with mortality, and the nutritional status of the children modified the effect of hypernatraemia on diarrhoeal mortality. The strong association between diarrhoeal death and hypoproteinaemia may be due to the effect of the pre-existing malnutrition of these patients and/or their loss of protein during shigella infection. The various risk factors that we have identified could be used as a prognostic guide by physicians treating such patients.

Adolescent↗
PubMed1985

Epidemiology and serology of Giardia lamblia in a developing country: Bangladesh.

The age-specific prevalence of Giardia lamblia was determined in two Bangladeshi villages and malnourished children in hospital in Dhaka City. Age-specific acquisition rates, the duration of infection and age-specific sero-positivity to (immunofluorescent assay) G. lamblia trophozoites were determined. Infection was acquired early (less than one year) and in 16% of infected children persisted for longer than three months. Prevalence was higher in 5 to 10-year-old village children (21%) and one to five-year-old malnourished children (51%). Over 40% of the children much less than 7 years acquired G. lamblia within 18 months; acquisition rates did not change with age. Positive antibody titres were acquired between six months and one year and the prevalence of sero-positivity remained high in all age groups No association was found between positive antibody titres and positive stool examinations. In developing countries serum antibodies are useful epidemiologically, but are not diagnostic in the individual patient.

Adolescent↗
PubMed1985

Fourteen years of shigellosis in Dhaka: an epidemiological analysis.

We examined whether the proportion of Shigellae patients among diarrhoeal cases, the distribution, species, case-fatality rates and hospital visits changed over time in Dhaka. We isolated 19639 Shigella strains from 822812 diarrhoea cases treated at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), between 1969 and 1982. The number of cases increased from 209 (2.5%) in 1969 to 4833 (7.7%) in 1976. Extrapolating from a 4% vigorous systematic sample of ICDDR,B hospital visits shigellosis cases and their proportion among diarrhoea cases increased to more than 9500 (12.0%) in 1981. The prevalence of various shigellae species altered over time. For example: in 1969 Shigella flexneri predominated in 74% of all Shigella cases; in 1973 Shigella dysenteriae accounted for 56%, and in 1981 Shigella flexneri again predominated (75%). More than 20% of all Shigella isolations were from infants: 60% in males and 40% in females. Over 7% of severe cases of Shigella infection referred from the outpatient department and admitted for treatment died. Nearly 40% of all the Shigella deaths were in infants of less than a year old while 49% were in 1-4 year old children. Increasing prevalence of shigellosis appears to be an important cause of diarrhoea in Dhaka especially among children. Areas with poor sanitation and water supply had higher prevalence. However, hospitalized cases represented a fraction of the actual problem. Resistance to antibiotics appears to be increasing and the development of new drugs and preventive methods within economic reach of less developed countries are crucial for reduction of the disease and related deaths.

Adolescent↗
PubMed1984

Changes in the trend of shigellosis in Dhaka: family study on secondary infection, clinical manifestation and sensitivity pattern: 1980.

The incidence of shigellosis and the death rate have increased and the resistance of shigellae to antibiotics has changed in Dhaka during our experiences. In 1980, we investigated the secondary infection and case rates, infection to case ratio, duration of illness, excretion of shigellae and antibiotic sensitivity pattern in 100 families with cases of shigellosis, culturing rectal swabs obtained by home visits for a 10-day period. Standard methods were used for culture and sensitivity tests. The over-all secondary infection rate in contacts was 27.3% and the case rate 10.7%. The rates were higher for Shigella flexneri than for Sh. dysenteriae. When the index cases were nought to four years old the secondary infection and case rates were higher than when index cases were older. Contacts aged nought to four years had highest attack rates. The average duration of excretion of Sh. flexneri was 4.5 and Sh. dysenteriae 2.6 days. Illness was one day longer for Sh. dysenteriae than for Sh. flexneri. Cases of shigellosis in hospital had higher rates of fever and blood in stool than those who were not in-patients. 40% of Sh. dysenteriae and 14% of Sh. flexneri were sensitive to tetracycline, 0 to 5% to streptomycin and 100% to sulphamethoxazole, trimethoprim and gentamicin. Incidence of Sh. flexneri had increased in 1980 but that of Sh. dysenteriae remained the same as in 1973 although Sh. dysenteriae type 1 appeared to be less infective in 1980 than in 1973.

Adolescent↗
PubMed1984

Nutritional ocular diseases and their association with diarrhoea in Matlab, Bangladesh.

The prevalence of visual defects, especially from causes associated with nutritional deficiencies, and their relation to diarrhoea in rural Bangladesh have been studied. A trained physician and a team of health workers examined visual defects in 149 villages, with a total population of 182 976. According to WHO classification, night blindness (XN) was found in only 0.03 persons/1000 population and 0.04 were found to have conjunctival xerosis (XIA) and Bitot's spot (XIB). Corneal xerosis (X2, X3A, X3B) also was found in 0.04 persons/1000. Night blindness combined with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was present in 1.69 persons/1000 and all combined stages of active xerophthalmia were seen in 0.06 persons/1000. Xerophthalmia prevailed up to age 19 years. Males had a significantly higher (2.9) incidence/1000 than did females (1.2). The total rate of keratomalacial scar for all ages was 0.31 persons/1000, while corneal opacity from other causes was seen in 2.25 persons/1000 population. More than 2.06 persons/1000 had ocular manifestations of one or more vitamin A deficiencies, while 4.47 persons/1000 had other ocular diseases, except for cataracts. Only 12.0% of all the corneal scars (XS) were due to keratomalacia. History of night blindness is a good indicator of vitamin A deficiency. In 96% of cases, night blindness was associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB). The onset of approximately 86% of cases of corneal xerosis (X2, X3A, X3B) and night blindness associated with conjunctival xerosis and Bitot's spot (XN + XIA + XIB) was related to diarrhoea.

Acute Disease↗