Biomedical subjects

J Chakraborty

Publications and source records attributed to J Chakraborty.

At least 73 records · Page 4Linked to original sources

PubMed1991

Effect on mortality of community-based maternity-care programme in rural Bangladesh.

Various community-based interventions have been proposed to improve maternity care, but hardly any studies have reported the effect of these measures on maternal mortality. In this study, the efficacy of a maternity-care programme to reduce maternal mortality has been evaluated in the context of a primary health-care project in rural Bangladesh. Trained midwives were posted in villages, and asked to attend as many home-deliveries as possible, detect and manage obstetric complications at onset, and accompany patients requiring referral for higher-level care to the project central maternity clinic. The effect of the programme was evaluated by comparison of direct obstetric maternal mortality ratios between the programme area and a neighbouring control area without midwives. Random assignment of the intervention was not possible but potentially confounding characteristics, including coverage and use of other health and family planning services, were similar in both areas. Maternal mortality ratios due to obstetric complications were similar in both areas during the 3 years preceding the start of the programme. By contrast, during the following 3 years, the ratio was significantly lower in the programme than in the control area (1.4 vs 3.8 per 1000 live births, p = 0.02). The findings suggest that maternal survival can be improved by the posting of midwives at village level, if they are given proper training, means, supervision, and back-up. The inputs for such a programme to succeed and the constraints of its replication on a large scale should not be underestimated.

Adolescent↗

PubMed1991

Concentrations of oestrone and 4-hydroxyandrostenedione in malignant and normal breast tissues.

4-Hydroxyandrostenedione (4-OHA) is a specific inhibitor of aromatase activity used for the treatment of breast cancer in post-menopausal women. Treatment with 4-OHA has been shown to inhibit the peripheral conversion of androstenedione to oestrone and reduce plasma oestrogen concentrations, but the effect of treatment on breast-tissue oestrone concentrations is not known. We have therefore examined the effect of treatment with 4-OHA on oestrone concentrations in normal and malignant breast tissues and also measured plasma and tissue 4-OHA concentrations. Changes in tumour oestrone concentrations were related to DNA polymerase alpha activity, a marker of cellular proliferation. Blood and breast-tissue samples were obtained before and 36 hr after treatment with 4-OHA. The mean plasma concentration of 4-OHA was 27.9 +/- 19.3 ng/ml, compared with levels of 33.7 +/- 25.6 ng/g for breast tumour and 13.5 +/- 11.5 ng/g for normal breast tissue. There was a significant correlation between 4-OHA concentrations in plasma and normal breast tissue (r = 0.91, p less than 0.001). Treatment with 4-OHA resulted in a significant (p less than 0.02) decrease in breast-tissue oestrone concentrations. For 3/4 tumour samples, a marked decrease in the concentration of oestrone (78 +/- 4%) was associated with a similar decrease (64 +/- 16%) in DNA polymerase alpha activity. It is concluded that treatment with 4-OHA effectively reduces breast-tissue exposure to oestrogen.

Aged↗

PubMed1991

Field trial of oral cholera vaccines in Bangladesh: serum vibriocidal and antitoxic antibodies as markers of the risk of cholera.

The relationship of serum vibriocidal (VC) and IgG anti-cholera toxin (CT) antibodies to the risk of cholera was evaluated during the first year of follow-up of recipients of three oral doses of B subunit (BS)-whole-cell vaccine, whole-cell vaccine, or Escherichia coli K12 strain placebo in Bangladesh. Acute sera from 121 cholera patients were compared with sera from 2592 contemporaneous community controls. Each doubling of VC titer was associated, on average, with a 22%-47% reduction of cholera risk in the three groups. In contrast, in the two groups that did not receive BS, anti-CT titers were directly associated with cholera and thus served as markers of higher cholera risk. Each vaccine conferred approximately 65% protective efficacy against cholera, but antibody titers did not correlate with vaccine efficacy, indicating that serum VC and anti-CT antibodies are poor markers of the longitudinal pattern of vaccine efficacy.

Administration, Oral↗

PubMed1991

ABO blood groups and the risk of diarrhea due to enterotoxigenic Escherichia coli.

To determine whether blood group O persons are at higher risk for enterotoxigenic Escherichia coli (ETEC) diarrhea, a case-control study was done for 17 months among rural Bangladeshis who were under systematic surveillance for diarrhea. Cases were children less than 3 years old who presented between 1 January 1985 and 1 June 1986 for care of heat labile (LT) or heat stabile toxin-producing ETEC diarrhea. Controls were of similar ages and were randomly selected from three community-based serosurveys between July 1985 and May 1986. No association between blood group O and ETEC diarrhea was found for the 510 cases and 641 controls, nor was an association evident for cases of each toxin phenotype. Further refinement of the case definition to include only patients with LT-ETEC diarrhea, without enteric copathogens, also failed to reveal a substantial association with blood group O. These data suggest that a strong association with ABO groups, analogous to that for cholera, does not exist for ETEC diarrhea.

ABO Blood-Group System↗

PubMed1991

Antibody responses after immunization with killed oral cholera vaccines during the 1985 vaccine field trial in Bangladesh.

Sera collected during the 1985 oral cholera vaccine trial in Matlab, Bangladesh, which demonstrated efficacy of a whole cell combined with cholera B subunit vaccine (WC/BS) and a whole cell only vaccine (WC), were analyzed for antitoxin and vibriocidal antibodies. Before vaccines were given, antitoxin titers were highest in children, especially those with O blood group, whereas vibriocidal titers rose throughout life. Two weeks after three doses of vaccine, geometric mean antitoxin titers were 2.5-4.5 times higher in vaccinees who received the WC/BS vaccine; the vibriocidal titers were 1.3-2.1 times higher in vaccinees who received either vaccine. The titer elevations were relatively brief and were barely detectable 7 months after the third dose even though significant levels of protection persisted greater than or equal to 3 years. Thus, the oral vaccines induced a serum response in this large field trial that was similar to that seen in earlier pilot studies, but the duration of the serum responses was much shorter than the duration of the protection.

Administration, Oral↗

PubMed1991

Diarrhoea mortality in rural Bangladeshi children.

Diarrhoeal mortality and hospital admissions for diarrhoea are described among children under the age of 5 years in a large rural Bangladeshi community during 1986-87. Acute watery (dehydrating) diarrhoea was associated with 11 per cent of all deaths among infants aged 1-11 months and 5 per cent among children aged 1-4 years. Acute non-watery diarrhoea, including bloody dysentery and diarrhoea with mucoid stools, was associated with 16 per cent of all deaths among children aged 1-4 years. In this age group, persistent diarrhoea, particularly when accompanied by recent and/or severe wasting, was associated with 63 per cent of all diarrhoeal deaths and 34 per cent of all deaths. These data suggest that exclusive emphasis on ORT will have little impact on diarrhoea mortality among children in rural Bangladesh. A broader strategy, both preventive and curative, including measles immunization, nutrition education, dietary management of diarrhoea, and the treatment of dysentery in the community, carries a greater potential.

Bangladesh↗

PubMed1991

Contraceptive use and breast-feeding duration in rural Bangladesh.

The association between contraceptive use and breast-feeding duration was investigated in 2380 women in rural Bangladesh where women usually stop breast-feeding once pregnant. Life table analysis showed that women receiving regular injections of depo medroxy progesterone acetate (DMPA) and those using non-hormonal contraception breast-fed significantly longer than women using no contraception. In contrast, women using oral contraceptives (combination of 0.5 mg norgestrel and 0.05 mg ethinyl oestradiol) did not breast-feed longer than women using no contraception. It is suspected that prolongation of breast-feeding obtained by delaying the next pregnancy with this oral contraceptive was offset by the depressing effect of oestradiol on lactation. Thus, in communities where prolonged breast-feeding is associated with improved child survival, non-hormonal contraceptive methods, or injectable DMPA, should be preferred for lactating women to oestrogen-containing oral contraceptives.

Bangladesh↗

PubMed1991

Measles among under-9-month-olds in rural Bangladesh: its significance for age at immunization.

Any decision to modify measles immunization strategies away from the use of the conventional vaccine given to children at 9 months of age to the adoption of recently proposed vaccine strains that can be given to 4-6-month-olds will depend on the age distribution of severe cases of measles in the community. Reported are the results of an analysis of two community-based measles surveillance systems in rural Bangladesh, which found that 17% of all measles cases reported for under-5-year-olds in a nonvaccinated population involved infants aged less than 9 months. In a vaccinated population from the same area, 31% of all measles cases reported for under-5-year-olds occurred among under-9-month-olds. Using a rather restrictive definition for measles-related deaths (those occurring within 6 weeks of the onset of the rash), the proportion of measles-related deaths that occurred before 9 months of age was 13% of all such deaths that were reported.

Age Factors↗

PubMed1990

Antibody-coated liposomes as a particulate solid phase for immunoassays. Measurement of urinary 'micro-albumin'.

A novel use of liposomes as a solid phase material achieving separation in immunoassays is described. Antibody-coated liposomes were prepared and used as a particulate solid phase in a radioimmunoassay procedure for urinary albumin. The assay was compared to a liquid phase albumin radioimmunoassay. The potential benefits of liposomes over other particulate solid phases are discussed. The use of liposomes in this manner need not be restricted to radioimmunoassay but should also be applicable to other immunoassays using alternative non-isotopic labels.

Albuminuria↗

PubMed1990

The effect of maternal and child health and family planning services on mortality: is prevention enough?

OBJECTIVE: To examine the impact on mortality of a child survival strategy, mostly based on preventive interventions. DESIGN: Cross sectional comparison of cause specific mortality in two communities differing in the type, coverage, and quality of maternal and child health and family planning services. In the intervention area the services were mainly preventive, community based, and home delivered. SUBJECTS: Neonates, infants, children, and mothers in two contiguous areas of rural Bangladesh. INTERVENTIONS: In the intervention area community health workers provided advice on contraception and on feeding and weaning babies; distributed oral rehydration solution, vitamin A tablets for children under 5, and ferrous fumarate and folic acid during pregnancy; immunised children; trained birth attendants in safe delivery and when to refer; treated minor ailments; and referred seriously ill people and malnourished children to a central clinic. MAIN OUTCOME MEASURES: Overall and age and cause specific death rates, obtained by a multiple step "verbal autopsy" process. RESULTS: During the two years covered by the study overall mortality was 17% lower among neonates, 9% lower among infants aged 1-5 months, 30% lower among children aged 6-35 months, and 19% lower among women living in the study area than in those living in the control area. These differences were mainly due to fewer deaths from neonatal tetanus, measles, persistent diarrhoea with severe malnutrition among children, and fewer abortions among women. CONCLUSIONS: The programme was effective in preventing some deaths. In addition to preventive components such as tetanus and measles immunisation, health and nutrition education, and family planning, curative services are needed to reduce mortality further.

Adolescent↗

PubMed1990

Field trial of oral cholera vaccines in Bangladesh: results from three-year follow-up.

The protective efficacy (PE) of B subunit killed whole-cell (BS-WC) and killed whole-cell-only (WC) oral cholera vaccines was assessed in a randomised double-blind field trial among children aged 2-15 years and women over 15 years in rural Bangladesh. Among the 62 285 subjects who received three doses of BS-WC, WC, or Escherichia coli K12 strain placebo, cumulative PE at 3 years of follow-up was 50% for BS-WC and 52% for WC. PE was similar against severe and non-severe cholera, but was significantly lower in children who were vaccinated at 2-5 years (26% for BS-WC; 23% for WC) than in older persons (63% for BS-WC; 68% for WC). Among persons vaccinated at 2-5 years, protection at 4-6 months of follow-up was similar to that for older persons, but rapidly waned thereafter and was not evident during the third year of follow-up. In contrast, persons vaccinated at older ages were protected even in the third year of follow-up (PE 40% for BS-WC; 62% for WC). PE was substantially higher against classical cholera (58% for BS-WC; 60% for WC) than against El Tor cholera (39% and 40%).

Administration, Oral↗

PubMed1990

Serum kinetics of the anti-cancer agent 4-hydroxyandrostenedione in the rat.

A previously described radioimmunoassay (RIA) method for the measurement of 4-hydroxyandrostenedione (4-OHA) was used to investigate the serum drug levels attained after a single oral dose in male and female rats. Marked variability of serum drug concentrations and their time course were evident in male animals at all dose levels. In the female rat, in contrast, serum 4-OHA showed fewer individual differences, rose more rapidly and was sustained at substantially higher concentrations. In all animals, 4-OHA appeared in the serum within 0.5 h following the oral dose and persisted for at least 48 h. Doubling the dose from 8 mg/kg produced a disproportionately large elevation in serum drug levels, but a further increase to 32 mg/kg did not further increase serum levels.

Androstenedione↗

PubMed1990

Radioimmunoassay of the anti-cancer agent 4-hydroxyandrostenedione in body fluids.

Antibodies were produced in sheep against a new anti-breast cancer drug 4-hydroxyandrostenedione (4-OHA) using two hapten-ovalbumin conjugates. One of these conjugates (4-hydroxytestosterone-ovalbumin) produced an antiserum suitable for the development of a radioimmunoassay that would allow direct measurement of 4-OHA in plasma at concentrations down to 82 pmol/l, with adequate accuracy, precision and scope for further sensitivity. Although this assay would measure 4-hydroxytestosterone (4-OHT) in addition to 4-OHA, the present data suggest that the magnitude of any interference from endogenous steroids and those derived from 4-OHA could only be minimal. A comparison of solvent-extracted and unextracted samples showed that only unconjugated drug was analysed by this radioimmunoassay. A study of plasma protein binding of 4-OHA showed that at therapeutic concentrations, between 13.5 and 16.5% of plasma 4-OHA was not bound to proteins. This assay system could be a useful adjunct to the future development of 4-OHA as an anti-cancer drug.

Androstenedione↗

PubMed1990

Field trial of oral cholera vaccines in Bangladesh: evaluation of anti-bacterial and anti-toxic breast-milk immunity in response to ingestion of the vaccines.

In a field trial conducted in Bangladesh, ingestion of either B subunit-killed whole cell (BS-WC) or killed whole cell (WC) oral cholera vaccines by mothers was associated with a 47% reduction of the risk of cholera in their non-vaccinated children aged under 36 months. Because vaccine-induced breast-milk immunity seemed a possible explanation for these findings, we evaluated anti-lipopolysaccharide (LPS) and anti-cholera toxin (CT) IgA antibody responses in breast milk collected during the trial from 53 lactating women who ingested three doses of BS-WC, WC, or an Escherichia coli K12 strain (K12). Despite induction of moderate vibriocidal (1.4 to 2.0-fold) and anti-CT (4.5-fold) serum antibody responses, the vaccines did not elicit significant rises of anti-LPS or anti-CT IgA breast-milk antibodies. The failure of the vaccines to elicit significant levels of breast-milk anti-cholera antibodies suggests an alternative explanation for protection of young children by maternal vaccination, such as interruption of maternal-child transmission of Vibrio cholerae 01.

Administration, Oral↗

PubMed1990

Perinatal mortality in Matlab, Bangladesh: a community-based study.

Perinatal deaths, comprising stillbirths and deaths during the first week of life, were monitored over the eight-year period 1979 to 1986 in a rural Bangladeshi population of 196,000. The perinatal mortality rate was 75 per 1000 total births. The rate was 13% higher in males than females. Stillbirth and early neonatal mortality rates were 37 and 38 per 1000 total births, respectively. The major causes of perinatal deaths are presented, as well as some of the maternal determinants. During the period under study, perinatal mortality declined regularly and significantly over time in an area covered by an intensive Family Planning and Health Services programme, but not in the adjacent control area. This raises the issue of the impact of such a programme upon perinatal mortality, and the need to include a strong maternity care component into primary healthcare strategies if further reductions of perinatal mortality are to be achieved.

Bangladesh↗

PubMed1990

Breast feeding and the risk of severe cholera in rural Bangladeshi children.

The association between breast feeding and the risk of severe cholera was examined in a case-control study of rural Bangladeshi children under 36 months of age who were studied in 1985-1986 during a field trial of killed oral cholera vaccines. A total of 116 cases who were treated for severe cholera were compared with 464 age-matched community controls without severe cholera. Overall, the odds ratio relating breast feeding to severe cholera (0.30, p less than 0.0001) reflected a 70% reduction in the risk of severe cholera among breast-fed children. The estimated reduction of risk declined with age, but was clearly evident in children up to 30 months of age. Although the association between breast feeding and a reduced risk of severe cholera was not significantly greater in children of mothers who had received cholera vaccine than in children whose mothers had received placebo during the trial, maternal vaccination per se was suggestively associated with a reduced risk of severe cholera in their nonvaccinated children (odds ratio = 0.53, p = 0.05). These results indicate that breast feeding was associated with a substantial reduction of the risk of severe cholera and raise the possibility that vaccination of mothers may provide protection to their young children in endemic settings.

Bangladesh↗

PubMed1990

Impact of measles vaccination on childhood mortality in rural Bangladesh.

This study examines the impact of measles vaccination on childhood mortality, based on longitudinal data from the Matlab maternal and child health/family planning programme in rural Bangladesh. It analyses the mortality experience of 8135 vaccinated and 8135 randomly matched nonvaccinated children aged 9-60 months, who were observed from March 1982 to October 1985. The results indicate that measles vaccination had a pronounced impact on both short- and long-term survival--the mortality rates for vaccinated children were as much as 46% less than those for nonvaccinated children. Immunization of children aged up to 3 years with measles vaccine appears to improve significantly their subsequent chances of survival. The findings underscore the need to give greater priority to measles vaccination within primary health care programmes in settings such as rural Bangladesh.

Bangladesh↗

PubMed1989

Oral cholera vaccines containing B-subunit-killed whole cells and killed whole cells only. II. Field evaluation of cross-protection against other members of the Vibrionaceae family.

Because of demonstrable cross-reactivity of cellular antigens contained in B subunit-killed whole-cell (BS-WC) and killed whole-cell-only (WC) oral cholera vaccines with antigens of various non-cholera species of the family Vibrionaceae (NCV), the protection conferred by the vaccines against diarrhoea associated with NCV was evaluated during a randomized, double-blind field trial in Bangladesh. Children aged 2-15 years and women aged greater than 15 years (62,285 in number) received three doses of BS-WC vaccine, WC-only vaccine, or a placebo consisting of Escherichia coli K12 strain (K12). During 1 year of follow-up, the incidence of treated episodes of diarrhoea associated with non-cholera vibrios known to be enteric pathogens (non-01 Vibrio cholerae, V. fluvialis, V. parahaemolyticus, V. mimicus) in the placebo group was low (1.9 cases per 10,000 recipients) and identical to that for the two vaccine groups combined. The incidence (per 10,000 recipients) of treated diarrhoeal episodes associated with Aeromonas species was considerably higher, but nearly identical in the three groups (26.1 cases for BS-WC, 26.0 cases for WC; 25.9 cases for K12). Pleisiomonas shigelloides was not isolated from any participant. It is concluded that NCV other than Aeromonas were rarely isolated from diarrhoeal patients in our study population and that killed oral vaccines which were effective against cholera exhibited no detectable cross-protection against diarrhoea associated with NCV organisms.

Administration, Oral↗