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Biomedical subjects

M Whitehead

Publications and source records attributed to M Whitehead.

At least 19 recordsLinked to original sources
PubMed2004

Effect of long-term estrogen therapy on dopaminergic responsivity in post-menopausal women--a preliminary study.

Females have a higher prevalence than men of neuropsychiatric disorders in which dopaminergic abnormalities play a prominent role, e.g. very late-onset schizophrenia and Parkinson's disease (PD). The biological basis of these sex differences is unknown but may include modulation of the dopaminergic system by sex hormones, as there is preliminary evidence that estrogen modulates treatment response in these disorders. Furthermore, sex differences in dopamine-mediated cognitive decline suggest estrogen may also play a role in healthy aging. However, the effects of estrogen on the dopaminergic system are poorly understood, and nobody has examined the effect of long-term estrogen therapy (ET) on this system. We compared dopaminergic responsivity (growth hormone (GH) response to apomorphine) in post-menopausal women on ET to women who were ET-naïve. GH response to subcutaneous apomorphine (0.005 mg/kg) was measured in two groups of healthy post-menopausal women aged between 55 and 70 years: those taking ET (n = 13) and those who had never taken ET (n = 13). Neither group was taking any other medication. GH was measured at 15 min intervals from -30 min before administration of apomorphine to 90 min post-administration. GH response was measured in two ways: area under the curve (AUC) and maximum response over baseline (GH). There were no between-group differences in demographic or baseline variables. The ET treated women had a significantly greater (p = 0.03) AUC than ET naïve women (mean +/- S.D.; 5.3 +/- 4.7 vs. 2.6 +/- 2.3). However, (GH) did not differ significantly between groups (6.1 mU/l +/- 6.2 vs. 2.7 mU/l +/- S.D. = 4.1). Also, analysis of GH response over time revealed a significant main effect of time (p < 0.0005), and a group by time interaction (p = 0.004) , but no significant main effect of group. Our results suggest that ET may enhance dopaminergic responsivity in post-menopausal women. Estrogen deficiency following menopause may partly explain age and gender differences in late-onset neuropsychiatric disorders.

Aged↗
PubMed2004

The social and economic consequences of childhood asthma across the lifecourse: a systematic review.

BACKGROUND: Asthma prevalence rates are high, and may be increasing in the Western world, particularly among children. The aim of this study was to evaluate the longer-term social and economic consequences of having asthma as a child and to determine whether adverse consequences are more severe for poorer children. METHODS: Results from published and unpublished, quantitative and qualitative studies were synthesized narratively to examine the impact of childhood-onset asthma on school attendance, academic achievement and employment in adulthood. The question of whether the impact differed for different social groups was also examined. FINDINGS: Twenty-nine good quality studies were identified, including in total 12 183 children with asthma or wheeze. Compared with asymptomatic children, those with asthma missed more days of school (additional absence as a result of asthma ranged from 2.1 to 14.8 days). Studies of academic achievement found that children with asthma performed as well as their healthy peers. The existing evidence on labour market performance is sparse, but there is an indication that people with asthma during childhood experience disadvantage in later employment. In an examination of consequences by social position, children with asthma from deprived areas were more likely to miss school than their more affluent peers, and minority ethnic children were also more likely to have poor school attendance. The only qualitative study suggested that children with asthma strove to participate fully in every aspect of their daily lives. INTERPRETATION: Although asthma limits children's daily activities and affects their social activities, this research synthesis found little evidence of major, adverse long-term social and economic consequences in studies reviewed. Further longitudinal research using comparison groups is needed to fill key gaps in the existing evidence base.

Age of Onset↗
PubMed2003

A composite chiral pair of rotational bands in the odd-A nucleus 135Nd.

High-spin states in 135Nd were populated with the 110Pd(30Si,5n)135Nd reaction at a 30Si bombarding energy of 133 MeV. Two DeltaI=1 bands with close excitation energies and the same parity were observed. These bands are directly linked by DeltaI=1 and DeltaI=2 transitions. The chiral nature of these two bands is confirmed by comparison with three-dimensional tilted axis cranking calculations. This is the first observation of a three-quasiparticle chiral structure and establishes the primarily geometric nature of this phenomenon.

Journal Article↗
PubMed2003

A neural mechanism for sudden death after myocardial infarction.

By monitoring efferent cardiac sympathetic nerve activity (CSNA) directly in a conscious animal we observed, for the first time, that ventricular fibrillation (VF) following myocardial infarction (MI) was preceded by a paroxysm of CSNA which was not baroreflexmodulated. This observation has potential therapeutic implications.

Animals↗
PubMed2003

Effects of long-term estrogen replacement therapy on growth hormone response to pyridostigmine in healthy postmenopausal women.

OBJECTIVE: There is growing evidence that estrogen may protect against age-related cognitive decline and reduce the risk of developing Alzheimer's disease (AD) in healthy, postmenopausal women. The underlying biological basis for this is not known but may include preservation of cholinergic systems. Cholinergic dysfunction has been implicated in the aetiology of age-related memory impairment and AD. We studied the effect of prolonged use of estrogen replacement therapy (ERT) on central cholinergic tone in healthy postmenopausal women. METHOD: Growth hormone (GH) responses to oral pyridostigmine (120 mg) were measured over a 3 h period in thirty healthy postmenopausal women, 15 on long-term ERT and 15 ERT naïve. RESULTS: GH release following pyridostigmine was significantly larger in ERT treated women than in ERT naïve women. In addition within the ERT treated group there was a significant positive correlation between duration of estrogen treatment and GH response. CONCLUSIONS: Long-term ERT can enhance cholinergic function in postmenopausal women and this may be related to duration of estrogen treatment. Modulation of central cholinergic function may be one mechanism by which long-term ERT could preserve cognitive function in healthy, postmenopausal women.

Aged↗
PubMed2002

Survival of Escherichia coli O157:H7 in traditional African yoghurt fermentation.

Growth and survival of a nontoxigenic strain of Escherichia coli O157:H7 (ATCC 43888) was determined in traditionally fermented pasteurized milk. Preheated milk was inoculated with 1% (v/v) of a mixed culture of Lactobacillus delbrueckii ssp. bulgaricus (NCIMB 11778) and Streptococcus salivarius ssp. thermophilus (NCIMB 110368) and incubated at 25, 30, 37 or 43 degrees C for 24 h. E. coli O157:H7 (10(5) CFU/ml) were introduced into the milk pre- and post-fermentation. Fermented milk samples were subsequently stored at either 4 degrees C (refrigerator temperature) or 25 degrees C (to mimic African ambient temperature) for 5 days. After 24 h of fermentation, the pH of the samples fermented at the higher temperatures of 37-43 degrees C decreased from 6.8 to 4.4-4.0 ( +/- 0.2) whereas at the lower temperature of 25 degrees C, the pH decreased to pH 5.0 +/- 0.1. During this period, viable counts for E. coli O157:H7 increased from 10(5) to 10(8) - 10(9) CFU/ml except in milk fermented at 43 degrees C wherein viability declined to 10(4) CFU/ml. In fermented (25-30 degrees C) milk stored at 4 degrees C for 5 days, E. coli O157:H7 viability decreased from 10(8-9) to 10(6-7) CFU/ml whereas milk fermented at 43 degrees C resulted in loss of detectable cells. In contrast, storage of fermented milk samples at 25 degrees C for 5 days eventually resulted in complete loss of viability irrespective of fermentation temperature. Stationary phase E. coli O157:H7 inoculated post-fermentation (25 and 43 degrees C) survived during 4 degrees C storage, but not 25 degrees C storage. Fermentation temperature and subsequent storage temperature are critical to the growth and survival of E. coli O157:H7 in traditional fermented products involving yoghurt starter cultures.

Colony Count, Microbial↗
PubMed2001

Effects of estrogen replacement therapy on human brain aging: an in vivo 1H MRS study.

Estrogen replacement therapy (ERT) may preserve cognitive function in postmenopausal women, but the mechanism is unknown. Thus, the authors studied aging of parietal lobe and hippocampus using proton MR spectroscopy. ERT naïve postmenopausal women had a significant increase in choline-containing compounds (Cho) compared to long-term ERT users and young women. Cho reflects increased neuronal/glial membrane turnover. Thus, ERT's "neuroprotective" effect may include modulating the effects of age on neural integrity in brain regions involved in cognitive function.

Adult↗
PubMed2001

Prolactin response to d-fenfluramine in postmenopausal women on and off ERT: comparison with young women.

Estrogen is thought to have an impact on both psychological well being and cognitive function. The biological basis to this is not fully understood, but may involve estrogen's interactions with central serotonergic (5-HT) systems. Therefore, we studied the effect of long-term estrogen hormone replacement therapy (ERT) on central 5-HT tone in healthy postmenopausal women and made comparisons with young women. Prolactin (PRL) responses to the specific 5-HT releasing and re-uptake inhibiting agent, d-fenfluramine, were measured in three groups of healthy women: 11 young, 11 postmenopausal on long-term ERT, and 11 postmenopausal ERT naïve. PRL responses were significantly decreased in ERT naïve women compared to young healthy women. In contrast, PRL responses were not different between estrogen-treated and young women. Overall, there was a significant relationship between older age and lower PRL responsivity. These results suggest that central 5-HT tone is reduced in healthy postmenopausal women who are ERT naïve, but not in postmenopausal women who have received prolonged estrogen treatment. Estrogen may modulate age-related changes in 5-HT tone. This may partly explain why estrogen can decrease vulnerability to mood disorders and cognitive changes in postmenopausal women.

Adult↗
PubMed2001

The role of income differences in explaining social inequalities in self rated health in Sweden and Britain.

STUDY OBJECTIVE: To analyse to what extent differences in income, using two distinct measures-as distribution across quintiles and poverty-explain social inequalities in self rated health, for men and women, in Sweden and Britain. DESIGN: Series of cross sectional surveys, the Swedish Survey of Living Conditions (ULF) and the British General Household Survey (GHS), during the period 1992-95. PARTICIPANTS AND SETTING: Swedish and British men and women aged 25-64 years. Approximately 4000 Swedes and 12 500 Britons are interviewed each year in the cross sectional studies used. The sample contains 15 766 people in the Swedish dataset and 49 604 people in the British dataset. MAIN RESULTS: The magnitude of social inequalities in less than good self rated health was similar in Sweden and in Britain, but adjusting for income differences explained a greater part of these in Britain than in Sweden. In Britain the distribution across income quintiles explained 47% of the social inequalities in self rated health among women and 31% among men, while in Sweden it explained, for women 13% and for men 20%. Poverty explained 22% for British women and 8% for British men of the social inequalities in self rated health, while in Sweden poverty explained much less (men 2.5% and women 0%). CONCLUSIONS: The magnitude of social inequalities in self rated health was similar in Sweden and in Britain. However, the distribution of income across occupational social classes explains a larger part of these inequalities in Britain than in Sweden. One reason for this may be the differential exposure to low income and poverty in the two countries.

Adult↗
PubMed2000

Anti-endomysial and anti-gliadin antibodies in screening for coeliac disease in children at greater risk of developing coeliac disease.

AIMS: To determine the prevalence of coeliac disease in selected groups of children presenting to a paediatric department. METHODS: Children presenting to the Paediatric Department at Christchurch Hospital were enrolled upon identification of one or more factors associated with increased risk of coeliac disease. All subjects were screened with anti-endomysial antibody and antigliadin antibody tests. Those children with positive tests underwent small bowel biopsy. RESULTS: 36 of 153 children had abnormal antibody tests. Seven (4.5%) of 34 children who underwent small bowel biopsies were found to have histological findings consistent with coeliac disease. Five of these children had presented with symptoms not classically ascribed to coeliac disease (failure to gain weight or non-specific abdominal pain). CONCLUSIONS: The possibility of coeliac disease should be considered in children with atypical symptoms and the diagnosis excluded by appropriate testing. Recognition of the variable presentations associated with coeliac disease in children is clinically relevant.

Adolescent↗
PubMed2000

Are randomized trials of hormone replacement therapy in symptomatic women with breast cancer feasible?

OBJECTIVE: To evaluate the feasibility of conducting a large randomized trial of HRT in symptomatic women with early-stage breast cancer. DESIGN: Open randomized study. SETTING: Outpatient clinics at The Royal Marsden and St. George's Hospitals, London. PATIENT(S): One hundred postmenopausal women with early-stage breast cancer, experiencing vasomotor symptoms and/or vaginal dryness. INTERVENTION(S): Randomization (1:1) to HRT or no HRT for 6 months. MAIN OUTCOME MEASURE(S): Acceptance, continuance rates, and the reasons eligible women declined study entry. RESULT(S): Acceptance (38.8%) and continuance rates (>80%) were encouraging. The efficacy of HRT did not appear to be antagonized with concomitant tamoxifen. Seventy-five percent of women continued HRT after the study ended. Three women developed metastatic disease. Two used HRT. CONCLUSION(S): Despite informed consent, a national UK randomized trial of HRT should be feasible and has now been planned. Successful implementation necessitates the provision of information about HRT and the estrogen deficiency side effects of breast cancer therapy to health professionals and women with breast cancer.

Adult↗
PubMed2000

Social policies and the pathways to inequalities in health: a comparative analysis of lone mothers in Britain and Sweden.

The aim of this study is to contribute to the emerging field of health inequalities impact assessment. It develops further a conceptual framework that encompasses the policy context as well as the pathways leading from social position to inequalities in health. It then uses this framework for a comparative analysis of social policies and their points of potential impact on the pathways leading from lone motherhood to ill health in Britain and Sweden. The British General Household Survey and the Swedish Survey of Living Conditions are analysed for the 17 years from 1979 to 1995/96. First, the results show that the health of lone mothers is poor in Sweden as well as in Britain and, most notably, that the magnitude of the differential between lone and couple mothers is of a similar order in Sweden as in Britain. This is despite the more favourable social policies in Sweden, which our results indicate have protected lone mothers from poverty and insecurity in the labour market to a much greater degree than the equivalent British policies over the 1980s and 1990s. Second, the pathways leading to the observed health disadvantage of lone mothers appear to be very different in the two countries in relation to the identified policy entry points. Overall, in Britain, around 50% of the health disadvantage of lone mothers is accounted for by the mediating factors of poverty and joblessness, whereas in Sweden these factors only account for between 3% and 13% of the health gap. The final section discusses the implications of the findings for future policy intervention and research in the two countries.

Cross-Cultural Comparison↗
PubMed2000

Second primary malignancies following the treatment of early stage ovarian cancer: update of a study by the National Cancer Institute of Canada--Clinical Trials Group (NCIC-CTG).

BACKGROUND: Ovarian cancer is the leading cause of death from gynecological malignancies and the fourth most frequent fatal malignancy in women. Despite improved surgical techniques as many as 20% of women with early stage disease will eventually relapse and die from their disease. The post-operative management of these women remains controversial. Here we present the long term follow-up data of our previously published study, as well as the incidence of second primary malignancies in these women. PATIENTS AND METHODS: Two hundred fifty-seven eligible patients with stage I, IIA 'high risk' ovarian carcinoma and IIB, IIIO (disease confined to pelvis) were randomized to either whole abdominal radiotherapy 2.250 rads in ten fractions (107 patients), melphalan 8 mg/m2/d x 4 weeks x 18 courses (106 patients) or intraperitoneal chromic phosphate 10-20 mCi (44 patients). All patients were initially treated with pelvic radiotherapy. RESULTS: Overall survival estimates at 10 years were: 45% in the whole abdominal radiotherapy arm; 49% in the melphalan arm and 50% in the intraperitoneal chromic phosphate arm (P = 0.30). Relapse-free survival estimates at 10 years were: 50% in the whole abdominal radiotherapy arm, 62% in the melphalan arm and 51% in the chromic phosphate arm (P = 0.147). Long term follow-up has not demonstrated a significant difference between treatment arms. Second primary malignancies developed in 29 women (11%) after 2,229 person years of follow-up. This compares to 18.7 second primary malignancies which would have been expected in this group of age-matched controls and was statistically significant (P = 0.018). There was no significant difference in the total number of second primary malignancies between treatment arms. Melphalan appeared to be associated with an increased risk of developing leukemia/myelodysplastic syndrome compared to the whole abdominal radiotherapy arm (P = 0.06). CONCLUSIONS: Long-term follow-up has not demonstrated a significant difference in overall or disease free survival between treatment arms. An excess of second primary malignancies (35%) was observed suggesting that lifelong surveillance is required in this population. Further research with newer treatment programs are needed to improve the cure rates in this population.

Antineoplastic Agents, Alkylating↗
PubMed2000

Inequality in the social consequences of illness: how well do people with long-term illness fare in the British and Swedish labor markets?

The demand for unskilled labor has collapsed across industrialized societies, including Britain and Sweden, and rates of unemployment and economic inactivity have increased. The result is a reduction in total employment, primarily among men. These trends could be expected to hit particularly hard those people with chronic illness. The study tests two opposing hypotheses: (1) the increasingly flexible, deregulated labor market in Britain would result in an increased number of new jobs, and thus better employment opportunities for unskilled workers, including those with chronic illness; (2) the more regulated labor market in Sweden, with the associated health and social policies, would provide greater opportunities for jobs and job security for workers with chronic illness. Analysis of data on men from the British General Household Survey and the Swedish Survey of Living Conditions, 1979-1995, showed that employment rates were higher and rates of unemployment and economic inactivity were lower in Sweden than in Britain, and the differences in these rates across socioeconomic groups and between those with and without chronic illness were smaller in Sweden. The results support the hypothesis that active labor market policies and employment protection may increase the opportunities for people with chronic illness to remain in work.

Adult↗
PubMed2000

William Farr's legacy to the study of inequalities in health.

This section looks back to some of the ground-breaking contributions to public health, reproducing them in their original form and adding a commentary on their significance from a modern-day perspective. To complement this month's theme issue of the Bulletin, Margaret Whitehead assesses the importance of William Farr's contribution to the study of social inequalities in health.

England↗