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Biomedical subjects

C Bennett

Publications and source records attributed to C Bennett.

At least 37 records · Page 2Linked to original sources
PubMed1998

Physical, chemical, and histologic changes in dentin caries lesions of primary teeth induced by regular use of polyol chewing gums.

A previous clinical trial showed that long-term use of saliva-stimulating polyol (xylitol and sorbitol) chewing gums was associated with arrest of dental caries in young subjects. After a 20-22-month intervention (when the subjects were 8 years old), a total of 23 primary teeth with extensive dentin caries lesions whose surface in clinical examination was found to be totally rehardened (remineralized) could be removed because the teeth were near their physiologic exfoliation time. These teeth were subjected to histologic, microhardness, and electron microscopic tests. The majority of the specimens had been remineralized from the surface by a non-cellular-mediated process within the remaining collapsed, organic extracellular matrix associated with the remaining dentinal surface. Many of the underlying dentinal tubules were filled with a matrix that had been subsequently mineralized. Dental microanalyses showed that the topmost (outer) 20-microm-thick rehardened layer of the lesions exhibited the highest Ca:P ratio, which leveled off at a depth of approximately 150 microm. The rehardened surface layer (normally <0.1 mm in thickness) was significantly (P < 0.001) harder than sound dentin and nearly as hard as sound enamel. Although the main source of the mineral present in the rehardened layer was most likely of salivary origin, some extracellular remineralization was probably mediated by odontoblasts. The results complete the dinical diagnoses of the original trial and suggest that regular use of polyol chewing gums may induce changes in dentin caries lesions, which in histologic and physiochemical studies show typical characteristics of rehardening and mineralization.

Calcium↗
PubMed1998

Evidence for a common mutation in hereditary pancreatitis.

Hereditary pancreatitis is an autosomal dominant disorder with incomplete penetrance. It is characterised by recurring episodes of severe abdominal pain and often presents in childhood. Recently, a mutation in the cationic trypsinogen gene was identified in this disease. Previously, only one mutation at residue 117 of the trypsinogen gene has been found in the five separate hereditary pancreatitis families, four from the USA and one from Italy. Alteration of the Arg117 site is believed to disrupt a fail-safe mechanism for the inactivation of trypsin, leading to autodigestion of the pancreas under certain conditions. Molecular analysis of the trypsinogen gene was carried out on a hereditary pancreatitis family from the UK. The same G to A mutation at residue 117 was identified in this family, suggesting that this is a common mutation in hereditary pancreatitis.

Chronic Disease↗
PubMed1997

HIV and AIDS awareness: an evaluation of a short training programme for midwives.

In response to a Department of Health, England, circular encouraging policies of named voluntary antenatal HIV antibody testing, one West Midlands health authority in England introduced a policy of raising the issue proactively at the first antenatal attendance. In order to facilitate this policy a short staff education programme was provided for midwives. This paper reports on part of a study which aimed to evaluate the impact of the HIV awareness training programme. A sample of midwives (n = 65) was randomly selected for inclusion in the study. Thirty-three had attended training and 32 had not. Data were collected using a self-administered questionnaire exploring knowledge of aetiology of HIV/AIDS, knowledge of transmission, knowledge of obstetric and paediatric HIV, attitudes to HIV, issues related to antenatal HIV antibody testing and opinions about the HIV awareness training programme. Results indicated no significant difference in levels of knowledge or in attitude between those who had attended the training programme and those who had not. Similarly, no significant difference was found in terms of how midwives would react to women requesting HIV antibody testing. Many of the results contradict the current literature and as a conclusion it is suggested that there is a need to review HIV-related training for midwives.

AIDS Serodiagnosis↗
PubMed1997

An international study of the exposure of children to traffic.

OBJECTIVES: To examine the extent of international differences in children's exposure to traffic as pedestrians or bicyclists. DESIGN: Children's travel patterns were surveyed using a parent-child administered questionnaire. Children were sampled via primary schools, using a probability cluster sampling design. SETTING: Six cities in five countries: Melbourne and Perth (Australia), Montreal (Canada), Auckland (New Zealand), Umeå (Sweden), and Baltimore (USA). SUBJECTS: Children aged 6 and 9 years. MAIN OUTCOME MEASURES: Modes of travel on the school-home journey, total daily time spent walking, and the average daily number of roads crossed. MAIN FINDINGS: Responses were obtained from the parents of 13423 children. There are distinct patterns of children's travel in the six cities studied. Children's travel in the three Australasian cities, Melbourne, Perth and Auckland, is characterised by high car use, low levels of bicycling, and a steep decline in walking with increasing car ownership. In these cities, over a third of the children sampled spent less than five minutes walking per day. In Montreal, walking and public transport were the most common modes of travel. In Umeå, walking and bicycling predominated, with very low use of motorised transport. In comparison with children in the Australasian and North American cities, children in Umeå spend more time walking, with 87% of children walking for more than five minutes per day. CONCLUSIONS: There are large international differences in the extent to which children walk and cycle. These findings would suggest that differences in 'exposure to risk' may be an important contributor to international differences in pedestrian injury rates. There are also substantial differences in pedestrian exposure to risk by levels of car ownership-differences that may explain socioeconomic differentials in pedestrian injury rates.

Australia↗
PubMed1997

Visual coping scenarios to facilitate discussion of coping responses with impoverished women at risk for AIDS.

1. Impoverished and homeless women are prone to coping with life stresses through drug and alcohol use. 2. Visual coping scenarios are culturally sensitive strategies to help impoverished minority women discuss effective coping responses. 3. A visual coping scenario redirects attention from a negative emotional event to an effective problem-focused coping strategy.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Entrance qualifications and student performance in a hybrid problem based and traditional medical programme.

A hybrid problem based learning (PBL) and traditional medical programme was started at the Trinidad campus of the University of the West Indies in 1989. Analyses were carried out to determine the extent to which the entrance qualifications of the students were related to their performances at the examinations in the Phase I (preclinical and paraclinical) and Phase II (clinical) programmes. Students who were admitted on the basis of their results in the secondary school General Certificate of Examination (GCE), 'A' level scored higher at the Phase I, but not at the Phase II, level than those who already had university education. Among the 'A' level students, there was positive correlation between the total 'A' level scores and the examination marks in the medical programme, particularly at the Phase I level. Furthermore, multiple regression analyses indicated that the grades in 'A' level Chemistry and, to a lesser extent in Biology, had the most influence on performances at the Phase I examinations, with much less influence on performances at the Phase II examinations. These results suggest that good grades at 'A' level examinations are significant factors, but not the only important ones, that favour high achievement in the initial stages of this type of PBL/traditional medical programme.

Education, Medical, Undergraduate↗
PubMed1996

Conclusion and review of the Michigan Xylitol Programme (1986-1995) for the prevention of dental caries.

The major results of the Michigan Xylitol Programme (1986-1995) are summarised. The Programme consisted of several clinical trials and laboratory investigations designed to study the usage of xylitol-containing saliva stimulants in the prevention of dental caries. The trials patients included young (initially 6 year olds) and adult or geriatric subjects who were given saliva stimulants (mostly chewing gum) for periods of two weeks to 56 months. A special rationale behind these studies was the need to further test the validity of the 'pentitol-hexitol theory' in the prevention of caries. This theory has maintained that pentitols (sugar alcohols with five hydroxyl groups, such as xylitol) may be cariologically more effective than hexitols (sugar alcohols with six hydroxyl groups, such as sorbitol). The accumulated clinical, sialochemical and microbiologic evidence suggests that xylitol, a natural carbohydrate sweetener of the pentitol type, is more effective in preventing dental caries than sorbitol, and cariologically safer than sorbitol, a natural carbohydrate of the hexitol type. Sorbitol was found to be significantly less cariogenic than sucrose. The Programme's results shed additional light on the cariologic and oral biologic effects of natural, dietary polyols, and suggest that the usage of xylitol chewing gum (and in some cases xylitol dragées) can be considered a valuable additional tool in caries prevention and in stabilisation of caries in all age groups.

Adolescent↗
PubMed1995

Evidence that the APOE locus influences rate of disease progression in late onset familial Alzheimer's Disease but is not causative.

An association has been observed in several independent data sets between late onset Alzheimer's Disease (AD) and the APOE locus on chromosome 19. We have examined the genotype in family history positive (FHP) and family history negative (FHN) cases and find a distortion of the APOE allele frequencies in accord with previous studies. However, when we examined the allele distribution of the at-risk siblings of the FHP group we found an excess of the epsilon 4 allele which also differs significantly from historic controls but not from the affected siblings. The age distribution of the affected and unaffected siblings was similar, suggesting that the allelic frequency distortion in the unaffected siblings was not due to their being below the mean age of onset. Lod score linkage analysis, with age dependent onset and non-stringent specification of the genetic parameters, did not suggest linkage to the APOE locus. Furthermore, an analysis of variance of the age of disease free survival suggested that APOE genotype contributes a small fraction of the total variance indicating that the APOE locus is a poor predictor of disease free survival age within late onset families. One explanation for the age dependent association reported by other groups, and our results, is that the APOE locus enhances the rate of progression of the disease process in otherwise predisposed individuals and that variation at this locus is not able in and of itself to cause the disease. We suggest this hypothesis is compatible with the current literature regarding APOE and AD.

Age Factors↗
PubMed1995

Clinical features of early onset, familial Alzheimer's disease linked to chromosome 14.

Early onset familial Alzheimer's disease (AD) has an autosomal dominant mode of inheritance. Two genes are responsible for the majority of cases of this subtype of AD. Mutations in the beta-amyloid precursor protein (beta APP) gene on chromosome 21 have been shown to completely cosegregate with the disease. We and others have previously described the clinical features of families with beta APP mutations at the codon 717 locus in an attempt to define the phenotype associated with a valine to isoleucine (Val-->Ile) or a valine to glycine (Val-->Gly) change. More recently, a second locus for very early onset disease has been localized to chromosome 14. The results of linkage studies in some families suggesting linkage to both chromosomes have been explained by the suggestion of a second (centromeric) locus on chromosome 21. Here we report the clinical features and genetic analysis of a British pedigree (F74) with early onset AD in which neither the beta APP locus nor any other chromosome 21 locus segregates with the disease, but in which good evidence is seen for linkage on the long arm of chromosome 14. In particular we report marker data suggesting that the chromosome 14 disease locus is close to D14S43 and D14S77. Given the likelihood that F74 represents a chromosome 14 linked family, we describe the clinical features and make a limited clinical comparison with the beta APP717 Val-->Ile and beta APP717 Val-->Gly encoded families that have been previously described.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Condom use among female commercial sex workers in Nevada's legal brothels.

OBJECTIVES: The purpose of this study was to evaluate condom use and the incidence of breakage and slippage during vaginal intercourse among female prostitutes in legal Nevada brothels, where use of condoms is required by law. METHODS: Forty-one licensed prostitutes in three brothels were enrolled in a prospective trial in August 1993. Used condoms were collected to verify reported breaks visually. Retrospective breakage and slippage rates were obtained in a standardized interview. RESULTS: Condoms were used for every act of vaginal intercourse with a brothel client during the study period, as well as in the previous year. In the prospective study phase, condoms were used in 353 acts of vaginal intercourse with clients. No condoms broke, and none fell off the penis during intercourse. Only twice (0.6%) did condoms completely fall off during withdrawal. Twelve times (3.4%) during intercourse and 15 times (4.3%) during withdrawal, condoms slipped down the penis but did not fall off. CONCLUSIONS: These findings, among the lowest breakage and slippage rates published, suggest that regular condom use may lead to condom mastery and the development of techniques to reduce the likelihood of breakage and slippage.

Adult↗
PubMed1994

Lower urinary tract reconstruction following cystectomy in women using the Kock ileal reservoir with bilateral ureteroileal urethrostomy: initial clinical experience.

Since June 1990, 14 women 31 to 70 years old (mean age 57 years) have undergone lower urinary tract reconstruction by bilateral ureteroileal urethrostomy using a Kock ileal reservoir. Indications for cystectomy included transitional cell carcinoma in 9 patients, urachal adenocarcinoma in 2, cervical carcinoma in 1, mesenchymal tumor of endometrial origin in 1 and a fibrotic radiated bladder in 1. Early and late complications have been few, occurring in 2 patients and 1, respectively. Excellent continence has been achieved during the day and night in 100% of patients. Of the 14 patients 12 void volitionally per urethra without high residual volume, while 2 require intermittent catheterization. All patients are completely satisfied. Tumor recurred in the pelvis in 1 patient with an extensive mesenchymal tumor necessitating conversion to a continent cutaneous Kock reservoir. All patients are currently alive without evidence of disease. This initial experience with lower urinary tract reconstruction in women has yielded extraordinary results and we believe that the option of lower urinary tract reconstruction following cystectomy can be offered safely to selected female patients.

Adult↗