Search PubMed⌕ Search

Biomedical subjects

H Campbell

Publications and source records attributed to H Campbell.

At least 127 records · Page 7Linked to original sources
PubMed1991

Nakahara Memorial Lecture. Pathways of carcinogenesis--genetic and epigenetic.

Considerable experimental evidence has developed to argue that carcinogenesis occurs in a series of stages whose characteristics allow division into the distinct stages of initiation, promotion, and progression. The stage of initiation results from subtle genetic alterations in individual target cells caused both by experimental perturbations as well as by ambient environmental factors. Initiation of a cell may result from the mutation of one or a few key genes whose expression is modified by many other genes. Promoting agents induce the clonal development of initiated cells susceptible to the proliferative effects of the specific promoting agent. The stage of progression is characterized by evolving karyotypic instability and may be induced by specific clastogenic effects and/or agents, the latter termed progressor agents. Carcinogens may induce cancer by an action at all three stages or selectively by an action at any one or two of the individual stages of carcinogenesis. Cancer then develops as a result of fortuitous, endogenous, or ambient environmental factors, thus accounting for the action of both genotoxic and nongenotoxic agents as carcinogens.

Animals↗
PubMed1991

Coincidence of malaria parasitaemia and abnormal chest X-ray findings in young Gambian children.

Weekly surveillance of Gambian children aged less than 5 years for both acute lower respiratory infections (ALRI) and clinical malaria showed a high rate of coincidence between abnormal chest X-ray findings and high levels of malaria parasitaemia. Generalized interstitial X-ray changes were particularly associated with these cases of malaria parasitaemia. It is suggested that such ALRIs in these children may be attributable to malaria.

Child, Preschool↗
PubMed1991

Evaluation of a computerized field data collection system for health surveys.

A customized field data collection system (FDCS) has been developed for a hand-held computer to collect and check questionnaire data. The data quality, preparation time, and user acceptability of the system were evaluated during a malaria morbidity survey in Bakau, the Gambia. Eight field-workers collected data with either the FDCS or on paper questionnaire forms in alternate weeks over a 6-week period. Significantly fewer item errors occurred with the FDCS, and by the end of the survey period interview times were significantly less with the FDCS than with the paper and pencil questionnaire. Advanced appropriate technology may have a useful role in providing accurate and rapid information, particularly in overcoming bottlenecks in data processing, and in obviating the need for costly expertise and equipment. In developing countries this could help to improve the quality of data on health care.

Data Collection↗
PubMed1990

Antibody persistence in Gambian children after high-dose Edmonston-Zagreb measles vaccine.

Measles antibody concentrations in Gambian children immunised at 4 months of age with a high-dose Edmonston-Zagreb (EZ) measles vaccine or at 9 months with conventional Schwarz vaccine were measured 5 months after vaccination, and at 18 and 36 months of age. Schwarz vaccinees produced, on average, a 2.4-fold higher concentration of measles haemagglutinin inhibiting (HAI) antibody than EZ vaccinees, but at 36 months of age 82 of 93 (88%) EZ vaccinees and 83 of 87 (95%) Schwarz vaccinees had measles plaque-neutralising antibody concentrations above the assumed protective level of 200 mIU/ml (p greater than 0.1). HAI antibody concentrations 5 months after vaccination were inversely related to the presence of maternal antibody at vaccination, but above protective levels; at 18 and 36 months of age there was no relation to antibody concentration at vaccination, and decay of HAI antibody between 18 and 36 months of age was similar for EZ and Schwarz vaccinees.

Age Factors↗
PubMed1990

Malaria in a peri-urban area of The Gambia.

A clinical and entomological survey of malaria was carried out in Bakau, a peri-urban coastal settlement in The Gambia, from June 1988-May 1989. Only 41 of a cohort of 560 children, aged from three months to nine-years-old, experienced a clinical episode of malaria during the observation period. The majority of cases were identified at clinics and not by regular community surveillance. In Bakau Old Town episodes of malaria were more common on the periphery of the settlement, adjacent to typical anopheline breeding sites, than in the centre. Overall malaria cases were not significantly clustered in space and time, although three pairs of cases among children sleeping in the same room at the same time were identified. A cross-sectional survey in November, at the end of the rainy season, revealed a point prevalence parasitaemia of 2.0% and a spleen rate of 0.3%. All malariometric parameters measured were much lower than any found in comparable studies undertaken in rural areas of the country, reflecting the low number of malaria vectors, Anopheles gambiae complex mosquitoes, found in Bakau. Chloroquine consumption, sleeping under bednets, houses with ceilings, the use of insecticide aerosols and burning traditional mosquito repellents may all have contributed to the low prevalence of malaria in the study area.

Animals↗
PubMed1990

Acute lower respiratory infections in Gambian children: maternal perception of illness.

A study of mothers' perceptions of childhood acute respiratory infections (ARI) was performed in a rural Gambian population. A total of 25,046 interviews were recorded over a 1-year period with mothers from three villages and four hamlets, and these were analysed together with the results of surveillance of their children for episodes of ARI. Mothers recognized acute lower respiratory infection as a severe disease and recognized fast and difficult breathing as features which discriminated it from upper respiratory infections (sensitivity 73%, specificity 73%). They sought treatment for their children on 51% of occasions when chest pain was reported and on 70% of occasions when 'open chest' was reported. We conclude that even in poorly educated populations in which traditional medical beliefs and practices are widespread, it may be possible to educate mothers to identify lower respiratory infections and to seek early treatment. Community education should play a major role in all national ARI programmes and may be a critical determinant of the success of case management strategies in preventing ARI-related mortality in children.

Acute Disease↗
PubMed1990

The impact of private residential and nursing care on statutory residential and hospital care of elderly people in south Belfast.

Dependency levels were compared in residents of private, voluntary and statutory residential homes, private nursing homes and patients in geriatric continuing-care wards in South Belfast. Dependency levels were least in private and voluntary residential homes, were similar in residential and private nursing homes, but were very much greater in the geriatric wards. Evidence of dementia was found in 23% of residents of voluntary homes, 35% of residents of private residential homes, 61% of residents of statutory residential homes, 54% of those in private nursing homes and 80% of patients in geriatric wards. Severe degrees of immobility and incontinence were commoner in nursing than in residential homes, but much commoner in geriatric wards. The number of private residential and nursing home places in the area studied has increased three- to five-fold since a previous survey in 1985. In this time, dependency levels, and frequencies of dementia, immobility and incontinence have increased in both statutory residential homes and geriatric continuing-care wards. It appears, therefore, that private residential and nursing homes take rather less dependent old people and that highly dependent old people are being concentrated in hospital.

Activities of Daily Living↗
PubMed1990

Serologic responses to an Haemophilus influenzae type b polysaccharide-Neisseria meningitidis outer membrane protein conjugate vaccine in very young Gambian infants.

Recent studies in the United States and Europe have shown that Haemophilus influenzae type b polysaccharide-protein conjugate vaccines can induce protective antibody levels in young infants, but it was not clear that this would be the case in African infants, to whom H influenzae vaccines must be given at a very early age to prevent disease caused by H influenzae. Therefore, antibody responses to an H influenzae type b polysaccharide-Neisseria meningitidis outer membrane protein conjugate vaccine were measured in very young Gambian infants. In the first group (n = 85), to whom the vaccine was given at the ages of 1 and 3 months, the geometric mean antibody level rose from a prevaccination level of 0.23 microgram/mL to a postvaccination level of 1.27 micrograms/mL, and in the second group (n = 56), vaccinated at the ages of 2 and 4 months, the prevaccination level of 0.16 microgram/mL rose to a postvaccination level of 1.59 micrograms/mL. These two final postvaccination levels did not differ significantly, and interpolation suggests that similar antibody levels were present in both groups of infants at the age of 3 months. This is the age by which protection would need to be achieved to protect against H influenzae meningitis in The Gambia and in other countries where the infection has similar epidemiologic characteristics. No significant side effects of vaccination were noted.

Antibodies, Bacterial↗
PubMed1990

Functional decline and survival in dependent elderly people.

A survey of dependency levels was carried out in 1985 and 1989 in 41 residents of old peoples homes and 25 patients in geriatric continuing care wards. There was an increase in all levels of dependency for those in both types of care. In the hospital patients surveyed in 1985, mortality was greatest in the most dependent, particularly those with impaired mental function. There was a positive correlation between length of survival and mental function. The results of this study emphasise the important role of dementia in the health and survival of old people.

Activities of Daily Living↗
PubMed1990

Tumor necrosis factor, interleukin-1 and beta 2-microglobulin levels in chronic hemodialysis patients.

We measured tumor necrosis factor (TNF alpha), interleukin-1 (IL1-B), and beta-2 microglobulin (B2M) levels in 10 chronic hemodialysis patients before and during dialysis with six different dialysate/dialyzer combinations. The mean pre-dialysis serum level of B2M was 23.4 +/- 11.1 mg/L (nl less than 3 mg/L). There was no significant effect of hemodialysis with any dialysate/dialyzer combination on intradialytic serum B2M levels. Five patients had detectable pre-dialysis serum levels of TNF alpha (greater than 40 pg/ml) at least once and 2 had detectable levels prior to all dialyses. Six patients had detectable pre-dialysis serum levels of IL1-B (greater than 20 pg/ml) at least once, and 2 had detectable levels prior to all dialyses. Serum TNF alpha, IL1-B and B2M levels were not significantly correlated with one another. Our data do not support the hypothesis that blood-membrane interactions significantly affect circulating levels of TNF alpha, IL1-B or B2M. Chronic high level elevations of plasma IL1-B and TNF alpha are not uniformly observed in hemodialysis patients, arguing against a role for these substances as systemic uremic toxins.

Acetates↗
PubMed1990

A population study of renal function in sickle cell anemia.

To define normal limits for serum creatinine levels, as well as to explore the relationship between age and the prevalence and severity of renal disease in patients with sickle cell anemia (SCA), we retrospectively analyzed renal function parameters in 368 patients followed in our SCA clinic. Dipstick proteinuria was present in 78 patients (20.6%). Chronic renal insufficiency (CRI) was present in 17 patients (4.6%) and showed a high degree of association with proteinuria and increased age. In patients with CRI, the severity of renal dysfunction was also age-related. In the 284 patients without proteinuria or CRI, mean serum creatinine levels were lower than predicted. We conclude that in patients with SCA, serum creatinine levels at the upper limit of normal should be regarded with suspicion, and that the prevalence and severity of proteinuria and CRI in SCA is high and increases with age.

Adult↗
PubMed1989

Latex agglutination test for diagnosing pneumococcal pneumonia in children in developing countries.

OBJECTIVE: To prepare and assess the sensitivity and specificity of a latex agglutination test specific for the serotype of antigen in diagnosing pneumococcal pneumonia in Gambian children. DESIGN: Comparison of agglutination test specific for serotype with culture of blood and lung aspirates, countercurrent immunoelectrophoresis, and commercial latex agglutination tests in diagnosing pneumococcal pneumonia. Cross reaction studies and investigation of 102 control children to determine specificity of agglutination test specific for serotype. SETTING: General medical ward of Medical Research Council laboratories, The Gambia. PATIENTS: 101 Gambian children aged between 2 months and 10 years admitted with severe pneumonia. INTERVENTIONS: Serum samples were boiled and treated with edetic acid, and urine samples were boiled and concentrated 25 times before testing. END POINT: A latex agglutination test specific for the serotype of pneumococcal antigen that is sensitive and highly specific for detecting pneumococcus in the urine of patients with pneumococcal pneumonia. MEASUREMENTS AND MAIN RESULTS: Concentrated urine samples from 16 of the 21 children (76%) with pneumococcal pneumonia established by results of culture of blood or lung aspirates gave a positive result with the agglutination test specific for serotype, whereas only four of the 102 urine samples obtained from control children without pneumonia gave positive results. The serotypes of antigens detected in the urine of children with pneumococcal pneumonia and the serotypes of pneumococci isolated from cultures of blood or lung aspirates were the same in all cases. CONCLUSIONS: When performed on urine samples the agglutination test specific for serotype has a high specificity and is more sensitive than culture of blood or lung aspirates, commercial agglutination tests, or countercurrent immunoelectrophoresis in identifying pneumococcal pneumonia. It is easy to use and should be especially useful in communities with limited laboratory facilities.

Antigens, Bacterial↗
PubMed1989

Assessment of clinical criteria for identification of severe acute lower respiratory tract infections in children.

222 acute lower respiratory tract infections (LRI), as defined by the World Health Organisation, were identified during one year's surveillance of a cohort of 500 Gambian children aged 0 to 4 years. Symptoms and signs at presentation were related to radiological evidence of lobar consolidation, indicating severe LRI. In infants, a fever of greater than 38.5 degrees C, refusal to breast-feed, or the presence of vomiting were the best predictors of severe LRI. In children aged 1 to 4 years, a fever of greater than 38.5 degrees C or a respiratory rate greater than 60/min were the most accurate clinical signs for severe LRI. Chest indrawing did not discriminate severe LRI. These community-based findings differ from results of hospital-based studies.

Acute Disease↗
PubMed1989

Subacute sclerosing panencephalitis. Changes on CT scan during acute relapse.

A 19-year-old female patient presented in an acute state of akinetic mutism. Serological analysis of serum and cerebrospinal fluid demonstrated the presence of antibodies to measles virus. CT scan carried out during this acute phase of relapse demonstrated white matter enhancement affecting the cortical white matter of the frontal lobes and corpus callosum. These features indicate that active demyelination occurs during acute relapse in subacute sclerosing panencephalitis (SSPE) and suggest that immunotherapy should be considered during this acute phase.

Adolescent↗
PubMed1988

Trial of co-trimoxazole versus procaine penicillin with ampicillin in treatment of community-acquired pneumonia in young Gambian children.

134 Gambian children under 5 years of age with severe pneumonia (as defined by the World Health Organisation classification of acute respiratory infections) were given either oral co-trimoxazole for 5 days, or a single intramuscular dose of fortified procaine penicillin and 5 days of oral ampicillin. At 2 weeks, there was no significant difference in outcome between the two groups. Co-trimoxazole is much less expensive than ampicillin or procaine penicillin, requires only twice-daily administration, and can be given by health-care staff with little training. The results support the use of co-trimoxazole as the antibiotic of first choice in outpatient management of young children with pneumonia in developing countries.

Ambulatory Care↗