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Biomedical subjects

S Bennett

Publications and source records attributed to S Bennett.

At least 127 records · Page 7Linked to original sources
PubMed1994

Subjective anxiety measurements and cortisol responses in adults who stutter.

Anxiety, as measured by self-report inventories and salivary cortisol levels, was examined in 11 males who stutter and 11 males who do not stutter during baseline, low stress, and high stress sessions. During the high stress session salivary cortisol was significantly greater in persons who stutter than in persons who do not stutter. No significant differences were found between the two groups on the State-Anxiety Inventory, Trait-Anxiety Inventory, or the Personal Report of Communication Apprehension. Significant differences in anxiety levels among the baseline, low stress, and high stress sessions for both groups of subjects were found for the State-Anxiety Inventory. No other significant differences or relationships were found between the two groups.

Adult↗
PubMed1994

Twin children in The Gambia: evidence for genetic regulation of physical characteristics in the presence of sub-optimal nutrition.

It has been demonstrated that physical growth characteristics are subject to genetic regulation. However, in developing countries, environmental factors such as food availability and frequent infections are associated with growth faltering which is particularly marked in infancy. We have conducted anthropometric measurements of a cohort of twin children aged less than 14 years living in a rural area of The Gambia to ascertain the extent to which genetic factors influence physical growth in the presence of a sub-optimal diet. Almost 25% of the children were more than 2SD below the median of the reference population in terms of their height-for-age Z score, indicating a marked level of undernutrition. Nevertheless, the within-pair variances were significantly less for monozygous than for dizygous twin pairs for the following variables: height, head circumference and body mass index (p < 0.01); weight (p < 0.02) and mid upper arm circumference (p < 0.1), indicating that there is a strong genetic influence on growth regulation despite the sub-optimal nutrition.

Adolescent↗
PubMed1994

A computer simulation of household sampling schemes for health surveys in developing countries.

BACKGROUND: Cluster sample surveys of health and nutrition in rural areas of developing countries frequently utilize the EPI (Expanded Programme on Immunization) method of selecting households where complete enumeration and systematic or simple random sampling (SRS) is considered impractical. The first household is selected by choosing a random direction from the centre of the community, counting the houses along that route, and picking one at random. Subsequent households are chosen by visiting that house which is nearest to the preceding one. METHODS: Using a computer, and data from a survey of all children in 30 villages in Uganda, we simulated the selection of samples of size 7, 15 and 30 children from each village using SRS, the EPI method, and four different modifications of the EPI method. RESULTS: The choice of sampling scheme for households had very little effect on the precision or bias of estimates of prevalence of malnutrition, or of recent morbidity, with EPI performing as well as SRS. However, the EPI scheme was inefficient and showed bias for variables relating to child care and for socioeconomic variables. Two of the modified EPI schemes (taking every fifth house and taking separate EPI samples in each quarter of the community) performed in general much better than EPI and almost as well as SRS. CONCLUSIONS: These results suggest that the unmodified EPI household sampling scheme may be adequate for rapid appraisal of morbidity prevalence or nutritional status of communities, but that it may not be appropriate for surveys which cover a wider range of topics such as health care, or seek to examine the association of health or nutrition with explanatory factors such as education and socioeconomic status. Other factors such as cost and the ability to monitor interviewers' performance should also be taken into account.

Bias↗
PubMed1994

Human antibody responses to Pfs 230, a sexual stage-specific surface antigen of Plasmodium falciparum: non-responsiveness is a stable phenotype but does not appear to be genetically regulated.

The 230 kD gamete surface protein of the malaria parasite Plasmodium falciparum (Pfs 230) is a target of transmission blocking antibodies. Anti-Pfs 230 antibodies are induced following natural infection with malaria but are not found in all P. falciparum-exposed individuals. In this study we have shown that approximately 40% of malaria-exposed Gambians do not make antibodies to the native Pfs 230 molecule. This phenotype is remarkably stable over time and does not appear to be related to age, malaria exposure or major histocompatibility complex genotype. Comparison of antibody responses in twins indicates that the anti-Pfs 230 response is not strictly genetically controlled, but a high degree of concordance within both dizygous and monozygous twin pairs suggests that factors associated with exposure to malaria in childhood may be important in determining the subsequent immune response.

Adolescent↗
PubMed1994

Review of child development teams.

Since the Court report was published in 1976 there has been a consensus that the needs of children with disabilities are best met by child development teams. This study explored the structure, facilities, and organisational elements of child development teams operating in the South East Thames region by means of a structured interview with senior professionals involved with organising services for children with disabilities in 14 of 15 health districts in the region. Although all districts had a designated child development team, not all core professionals were adequately represented and four of 14 districts had no child development centre. The quality of buildings and facilities was variable. Teams that did not have a physical base in the form of a centre had fewer staff in the service and poorer facilities. There is a need for further consensus work about broad guidelines on the requirements of child development teams. These will help to inform purchasing authorities about the needs of children with disabilities living in their districts.

Child↗
PubMed1994

Carrot and stick: state mechanisms to influence private provider behavior.

The behavior of private sector health care providers will depend critically on the environment within which they operate. A bewildering array of possible regulatory and incentive setting structures exist. Most developing countries have the basic legislation for regulation, but there are frequently difficulties in enforcing such controls. While process aspects of quality of care regulation are often the responsibility of professional organizations, these organizations may have limited incentives to be active in ensuring high quality medical car.e There has been less experience with the use of incentives to encourage appropriate behavior amongst private providers: this appears a promising area for further work. Above all, adequate information is essential both for the enforcement of regulations and the application of incentive mechanisms.

Consumer Organizations↗
PubMed1994

Nationwide survey of bednet use in rural Gambia.

A nationwide survey was carried out to investigate the use of bednets in rural areas of the Gambia, particularly among children under 5 years old and among pregnant women. A stratified multistage design was used; 360 compounds in 60 villages were visited. Overall, 58% of beds had a net, with very little difference between villages with primary health care (PHC) facilities and those without (non-PHC). Bednet use was higher in the Central Region (76%) than in the Western and Eastern Regions (both 51%). It was highest among the Jola ethnic group (77%) and lowest among Sarahulis and other minority groups. Use of bednets was higher among target groups (such as infants, children under 5 years old, and pregnant women) than among the general population, and reached a level of over 90% in these groups in the Central Region. Use was associated with possession of a metal bed and a radio. Previous trials of impregnated bednets in the Gambia have been carried out in the Central Region, where bednet use is highest. The efforts of the National Impregnated Bednet Programme should therefore concentrate on the other regions and among the minority ethnic groups in order to increase bednet ownership.

Adolescent↗
PubMed1993

Synergistic induction of rat microsomal CYP1A1 and CYP1A2 by acetone in combination with pyridine.

The effect of exposure to acetone, pyridine or acetone in combination with pyridine on microsomal CYP1A1, CYP1A2 and CYP2E1 levels and their catalytic activities was determined in the rat. CYP1A1 and CYP1A2 in the liver and CYP1A1 in the lung were induced along with their catalytic activities by either pyridine, acetone or acetone and pyridine. The induction by acetone and pyridine was greater than the additive effect of both compounds, indicating synergism. Acetone, pyridine or both compounds induced CYP2E1 protein to the same extent in the liver and lung. However, induction of CYP2E1 protein was accompanied by induction of its catalytic activity in the liver but not in the lung. This is the first reported induction of CYP1A proteins and catalytic activities (a) by acetone and (b) synergistically by xenobiotics.

Acetone↗
PubMed1993

In vitro replication dynamics of human culture-derived macrophages in a long term serum-free system.

Human peripheral blood monocytes maintained in a long term serum-free system were found to undergo extensive replication. Newly replicated culture-derived macrophages initially appeared as colonies of small cells on the adherent monolayer. After the appearance of these colonies, large numbers of nonadherent macrophages were observed. Using PKH26, a fluorescent tracking dye, the increase in cell number was attributed to a replicating pool of cells. Half of the monocytes present in the original monolayer were able to undergo at least one cycle of replication and of these, approximately 16% underwent three or more cycles of replication. Macrophages in the nonadherent state contained a larger proportion of cells that had undergone division compared with adherent cells. However, it appeared that only adherent macrophages were capable of replication, suggesting movement between the adherent and nonadherent states. Culture-derived macrophages were also predisposed to multinucleated giant cell formation; and in the nonadherent state, their capacity to form these cells increased. At the end of the study period, approximately 25% of the cells maintained in a nonadherent state had two or more nuclei, and 3% had 10 or more nuclei. By comparison, the adherent cells, over the same period, had 10% of cells with two or more nuclei and none had 10 or more nuclei. These multinucleated cells were found to arise through cell fusion.

Cell Adhesion↗
PubMed1993

Anopheles albimanus (Diptera: Culicidae) host selection patterns in three ecological areas of the coastal plains of Chiapas, southern Mexico.

The host-feeding patterns of Anopheles albimanus Wiedemann were described and the effect of host availability on these patterns was assessed in three different ecological areas of coastal Chiapas, Mexico. Resting mosquitoes were collected indoors and outdoors during rainy seasons. A 20% sample of blood-fed mosquitoes was tested to determine the source of the blood meal using an ELISA. The unweighted human blood index (HBI) of An. albimanus in the three areas ranged from 0.11 to 0.21. This mosquito species fed more frequently on bovines than on any other host, but the forage ratio indicated that there was also a high preference for equines. Some females tended to rest or complete their gonotrophic cycle indoors after feeding on animals, but females also fed on man and rested outdoors. Host availability and ecological conditions appeared to be responsible for differences observed in the HBI among areas.

Animals↗
PubMed1993

Randomized trial of umbilical arterial catheter position: clinical outcome.

In order to determine if umbilical arterial catheter position affects the incidence of necrotizing enterocolitis, clinical outcome was analysed in 308 infants whose umbilical arterial catheter had been randomly allocated to a high (n = 162) or a low (n = 146) position. Necrotizing enterocolitis was classified as suspected or confirmed; all renal, lower limb and local catheter complications were also recorded. High umbilical arterial catheters were in place for longer than low catheters, provided more samples and were removed as an emergency less often. Lower limb blanching and cyanosis were more common with low catheters. Eleven cases of confirmed necrotizing enterocolitis occurred in the "high" group and nine in the "low" group. One case of fatal aortic thrombosis was encountered in the high group. Positioning umbilical arterial catheters in a high position allowed longer functional use and did not increase the incidence of necrotizing enterocolitis.

Catheterization↗
PubMed1993

Mercury released from dental "silver" fillings provokes an increase in mercury- and antibiotic-resistant bacteria in oral and intestinal floras of primates.

In a survey of 640 human subjects, a subgroup of 356 persons without recent exposure to antibiotics demonstrated that those with a high prevalence of Hg resistance in their intestinal floras were significantly more likely to also have resistance to two or more antibiotics. This observation led us to consider the possibility that mercury released from amalgam ("silver") dental restorations might be a selective agent for both mercury- and antibiotic-resistant bacteria in the oral and intestinal floras of primates. Resistances to mercury and to several antibiotics were examined in the oral and intestinal floras of six adult monkeys prior to the installation of amalgam fillings, during the time they were in place, and after replacement of the amalgam fillings with glass ionomer fillings (in four of the monkeys). The monkeys were fed an antibiotic-free diet, and fecal mercury concentrations were monitored. There was a statistically significant increase in the incidence of mercury-resistant bacteria during the 5 weeks following installation of the amalgam fillings and during the 5 weeks immediately following their replacement with glass ionomer fillings. These peaks in incidence of mercury-resistant bacteria correlated with peaks of Hg elimination (as high as 1 mM in the feces) immediately following amalgam placement and immediately after replacement of the amalgam fillings. Representative mercury-resistant isolates of three selected bacterial families (oral streptococci, members of the family Enterobacteriaceae, and enterococci) were also resistant to one or more antibiotics, including ampicillin, tetracycline, streptomycin, kanamycin, and chloramphenicol. While such mercury- and antibiotic-resistant isolates among the staphylococci, the enterococci, and members of the family Enterobacteriaceae have been described, this is the first report of mercury resistance in the oral streptococci. Many of the enterobacterial strains were able to transfer mercury and antibiotic resistances together to laboratory bacterial recipients, suggesting that the loci for these resistances are genetically linked. Our findings indicate that mercury released from amalgam fillings can cause an enrichment of mercury resistance plasmids in the normal bacterial floras of primates. Many of these plasmids also carry antibiotic resistance, implicating the exposure to mercury from dental amalgams in an increased incidence of multiple antibiotic resistance plasmids in the normal floras of nonmedicated subjects.

Animals↗
PubMed1993

Immunoglobulin M and G antibody responses to Plasmodium falciparum glutamate-rich protein: correlation with clinical immunity in Gambian children.

The aims of the present study were to describe the age-related immunoglobulin M (IgM) and IgG response to part of a 220-kDa glutamate-rich protein (GLURP) from Plasmodium falciparum and to determine possible correlations of possession of these antibodies with malaria morbidity. IgM and IgG levels were measured with a recombinant fusion protein consisting of the carboxy-terminal 783 amino acids of the GLURP. Samples for the study were obtained during a longitudinal malaria morbidity survey performed in The Gambia; cross-sectional surveys were performed at the beginning of the transmission season in May and in October. Seropositivity rates increased with age to a maximum of 77% for IgM and 95% for IgG in adults. High prevalences of seropositivity were associated with certain human leukocyte antigen class II alleles (DRw8, DR9, DR7, DR4, DQw7, and DQw2) or haplotypes. The relationship between anti-GLURP489-1271 antibodies and clinical immunity is not clear; asymptomatically infected children aged 5 to 8 years had significantly higher levels of IgG than clinically ill children of the same age, suggesting that antibodies to the carboxy-terminal part of the GLURP may contribute to immunity to P. falciparum. However, this was not significant for younger children.

Adolescent↗