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Biomedical subjects

P J Boyle

Publications and source records attributed to P J Boyle.

At least 19 recordsLinked to original sources
PubMed2006

Smoking compromises cause-specific survival in patients with operable colorectal cancer.

AIMS: To assess whether active smoking compromises survival in patients with colorectal cancer. MATERIALS AND METHODS: We studied a regionally based cohort of 284 consecutive patients referred to the Tayside Cancer Centre for consideration of adjuvant treatment after curative surgery for colorectal cancer. RESULTS: Cause-specific survival was significantly worse (P = 0.0015) in patients who were actively smoking at the time of their first post-operative visit. The absolute difference in 5-year cause-specific survival (active smokers vs the rest) was 21%. In adjusted multi-variate analysis of patients after pathologically complete (R0) resection, the hazard ratio was 2.55 (95% confidence interval 1.40-4.64) in active smokers compared with non-smokers. T stage, number of positive nodes and co-morbidity score were also of independent prognostic influence. CONCLUSIONS: Persistent smoking was, in this small series, an important and independent predictor of cancer-related death after surgery for cancer of the large bowel. Because smoking and deprivation are related, some of the adverse effects of deprivation upon survival in this group of patients may be explained by smoking behaviour.

Chemotherapy, Adjuvant↗
PubMed2003

Spatial clustering of amyotrophic lateral sclerosis in Finland at place of birth and place of death.

Previous evidence for spatial clustering of amyotrophic lateral sclerosis is inconclusive. Studies that have identified apparent clusters have often been based on a small number of cases, which means the results may have occurred by chance processes. Also, most studies have used the geographic location at the time of death as the basis for cluster detection, rather than exploring clusters at other points in the life cycle. In this study, the authors examine 1,000 cases of amyotrophic lateral sclerosis distributed throughout Finland who died between June 1985 and December 1995. Using a spatial-scan statistic, the authors examine whether there are significant clusters of the disease at both time of birth and time of death. Two significant, neighboring clusters were identified in southeast and south-central Finland at the time of death. A single significant cluster was identified in southeast Finland at the time of birth, closely matching one of the clusters identified at the time of death. These results are based on a large sample of cases, and they provide convincing evidence of spatial clustering of this condition. The results demonstrate also that, if the cluster analysis is conducted at different stages of the cases' life cycle, different conclusions about where potential risk factors may exist might result.

Adult↗
PubMed2001

Do area-level population change, deprivation and variations in deprivation affect individual-level self-reported limiting long-term illness?

A previous study showed that variations in deprivation within small localities in England and Wales influenced the rates of self-reported limiting long-term illness, controlling for overall levels of deprivation. These results suggest that while morbidity is related to overall levels of material deprivation, the distribution of resources within small areas have a significant effect on health outcomes. However, it is possible that these area effects become redundant once individual-level characteristics are accounted for. This analysis examines whether area-level deprivation and variations in deprivation are significant indicators of individual-level limiting long-term illness, once individual characteristics have been accounted for.

Chronic Disease↗
PubMed2000

Hypoglycemia. Pathophysiology and treatment.

Hypoglycemia is a common consequence of many diabetes treatments. As is true for many therapies for diseases with major pathologic consequences, the benefits and risks of treatment must be balanced. In intensified diabetes management, hypoglycemia is not an insurmountable problem but is unfortunately inevitable using the methods of glucose control currently available. Patients with type 1 diabetes seem to be at greater risk than patients with type 2 disease. The health care team must strive to help the patient maintain normoglycemia. The results of the DCCT and the United Kingdom Prospective Diabetes Study prove that near normoglycemia is clearly in the patient's best interest. Patient education has become focused on minimizing hyperglycemia; counseling on the dangers of hypoglycemia has not been given the same stature. Emphasis must be placed on minimizing even minor subclinical hypoglycemia because it will contribute to a vicious cycle of hypoglycemia begetting hypoglycemia.

Blood Glucose↗
PubMed1999

The effect on morbidity of variability in deprivation and population stability in England and Wales: an investigation at small-area level.

We seek to determine whether variability in deprivation at small area level, and population stability, influence standardised morbidity ratios in England and Wales. A regression analysis was conducted with data from the 1991 British Census, in order to explain variation in morbidity. Both an area deprivation score (for electoral wards) and the within-area variability of deprivation scores were examined as possible determinants of morbidity (self-reported, limiting, long-term illness). Particular attention was focused on a spatially-sensitive measure of the variability of deprivation scores within a wider 'locality'. There was a significant, positive relationship between age-standardised limiting, long-term illness and deprivation. The variation in area deprivation scores within the small areas themselves was also significant and positive. However, the variation in deprivation scores calculated for both an electoral ward and its contiguous neighbours (the locality) was slightly more significant. Areas with higher relative levels of in-migration also had significantly lower standardised morbidity ratios. Multivariate models showed that the deprivation score, the variation in deprivation scores for the broader locality, and the measure of migration, were all significant in combination. Residual analysis showed that many areas in London had lower levels of morbidity than expected, while electoral wards in the coal mining valleys of South Wales had higher levels than expected. We conclude that, for small areas (wards) in England and Wales, morbidity is related to deprivation, variation in deprivation within and surrounding each area, and the proportion of the population that are migrants. Variations in deprivation influence standardised morbidity rates, and policies which widen inequalities will influence health outcomes. Resource allocation based simply on measures of deprivation, which ignore population change within the area and variations in deprivation in the locality, may be inefficient.

Censuses↗
PubMed1998

Localized well-differentiated thyroid carcinoma: survival analysis of prognostic factors and (131)I therapy.

BACKGROUND: Recommendations regarding therapeutic use of (131)I for patients with well-differentiated thyroid cancer remain controversial. Between 1969 and 1993, 1171 patients with papillary (including mixed) or follicular thyroid cancer were reported to the New Mexico Tumor Registry. Of these, 1075 cases (77.6% female, median age 41 years) were available for analysis of survival plots and previously recognized risk factors. Extent of operation was documented for 344 patients. METHODS: One hundred twenty-seven (37%) patients underwent postoperative (131)I ablation. Median follow-up was 99 months. A proportional hazards model was constructed using age, gender, stage, histology, and use of radioiodine. The same variables plus extent of operation were examined in the smaller group. RESULTS: Kaplan-Meier survival estimates at 12 years were 96.2% for patients younger than 45 years and 68.6% for those older than 45 years. Age, gender, and histology, but not stage, were important survival variables (P <.05). Adjusting for other risk factors, there was no apparent survival benefit associated with radioiodine following clinically appropriate thyroidectomy. Findings from the small group mirrored those of the large group. CONCLUSIONS: (131)I may not be as efficacious as previously believed for patients with well-differentiated thyroid cancer confined to the neck.

Adenocarcinoma, Follicular↗
PubMed1998

Modelling inter-ward migration in Hereford and Worcester: the importance of housing growth and tenure.

"In this paper, we use the 1991 Special Migration Statistics to analyse inter-ward flows in the British county of Hereford and Worcester. New modelling techniques...based on the Poisson distribution are used in this research which partially overcome the under-dispersion problem resulting from modelling zero and very small flows.... Analysis at this scale provides the potential for more detailed generalization about migration processes such as suburbanization, counterurbanization, intra-urban mobility, rural depopulation and the relationship between housing and demographic change at the local level. Unlike migration flows over long distances, which are often employment related, these flows are primarily motivated by residential requirements and housing type and growth are identified as key variables in the interpretation of these migration patterns."

Demography↗
PubMed1997

Alteration in brain glucose metabolism induced by hypoglycaemia in man.

Glucose is the usual fuel of brain tissue. As hypoglycaemia develops, a level of glycaemia is reached where glucose transport from the circulation is no longer sufficient to meet metabolic demands, and the brain signals for peripheral counter-regulatory responses and symptoms of hypoglycaemia ensue. The glycaemic threshold for these events can be shifted to lower glucose concentrations following a single episode of hypoglycaemia, and compensating central nervous system adaptations have been postulated in man. In nondiabetic subjects, rates of brain glucose uptake are initially impaired at a systemic glucose concentration of 3.6 mmol/l; whereas after 56 h of intermittent hypoglycaemia (3.0 mmol/l) brain uptake is preserved at normal rates even at 2.5 mmol/l. Increments in counter-regulatory hormones and symptoms are also triggered at lower glucose concentrations following recurrent hypoglycaemia. In 24 patients with insulin-dependent diabetes stratified into three equal groups by HbA1c value, those in the lowest third of HbA1c range had rates of brain glucose uptake at 3.0 mmol/l that were equivalent to rates measured at 5.3 mmol/l. Patients in the other HbA1c groups had rates of brain glucose uptake during hypoglycaemia that were reduced by 30% relative to normoglycaemia-comparable to reductions seen in non-diabetic subjects. Thus, alterations in glucose uptake occur in the brain in order to maintain normal brain metabolism following experimental and clinical hypoglycaemia. Because of this enhanced glucose uptake, the brain has no need to signal for counter-regulatory responses and hypoglycaemia unawareness occurs.

Brain↗
PubMed1996

Effect of population mixing and socioeconomic status in England and Wales, 1979-85, on lymphoblastic leukaemia in children.

OBJECTIVE: To examine the effects of migration, diversity of migrant origins, commuting, and socioeconomic status on the incidence of acute lymphoblastic leukaemia in childhood. DESIGN: Poisson regression analysis of incidence rates in relation to the variables of interest. SETTING: The 403 county districts of England and Wales during 1979-85. SUBJECTS: Children aged under 15 years. RESULTS: There were significant trends in the incidence of lymphoblastic leukaemia at ages 0-4 and 5-9 years with the proportion of children in a district who had recently entered the district. While there was no consistent relation between the proportion of recent incomers in the total population of a district and its incidence rate, the combination of higher migration with greater diversity of origins or distance moved was associated with higher incidence in both age groups. Incidence increased significantly at age 0-4 with the level of employment in a district and at age 5-9 with the proportion of households with access to a car. No significant trends were found with commuting. CONCLUSIONS: The results for level of child migration and diversity of total migration provide evidence of an effect of population mixing on the incidence of childhood leukaemia which is not restricted to areas experiencing the most extreme levels of mixing.

Adolescent↗
PubMed1996

Differential effects of physiological versus pathophysiological plasma concentrations of epinephrine and norepinephrine on ketone body metabolism and hepatic portal blood flow in man.

Few studies that have examined the effects of catecholamines on ketogenesis have considered the effects of catecholamines on hepatic portal blood flow. Since hepatic blood flow is a major determinant of hepatic ketogenesis (via modification of free fatty acid availability), interpretation of these studies is difficult. To better define the relative contributions of these variables, we studied the effects of physiological and pathophysiological plasma concentrations of epinephrine and norepinephrine on plasma ketone body concentrations and hepatic portal blood flow in controlled paired studies in young healthy male volunteers. To assess the effects of physiological catecholamine concentrations, each of eight subjects received 60-minute sequential infusions of epinephrine (10 ng/kg/min) and norepinephrine (32.5 ng/kg/min) together with a control infusion of heparin (0.4 U/kg/min) separated by 60-minute washout periods. Similar increments in plasma nonesterified fatty acid ([NEFA] to approximately 1 mmol/L) were observed during each infusion. The ketotic ratios, calculated as the ratio of plasma ketone bodies to fatty acids integrated above baseline for 90 and 120 minutes, respectively, for epinephrine and norepinephrine infusions were both significantly greater (P < .005 for each) than for the heparin control infusion. To assess the effects of pathophysiological plasma catecholamine concentrations, each of eight subjects also received sequential 60-minute infusions of epinephrine 60 ng/kg/min, norepinephrine 80 ng/kg/min (plus heparin 0.1 U/kg/min), and a separate control infusion of heparin with or without Intralipid (KabiVitrum, Alameda, CA). Whereas integrated plasma fatty acid levels were approximately twofold greater than those observed in the physiological protocol, the absolute integrated ketone body response to the pathophysiological concentration of epinephrine was significantly lower than that observed for the physiological dose of the hormone (P < .05). In contrast, the ketotic ratio for norepinephrine was significantly greater (P < .005) than for both epinephrine and the control infusion of heparin with or without Intralipid. Significant (P < .01) increases above baseline fasting levels were observed in plasma glucose and immunoreactive insulin concentrations during infusion of pathophysiological concentrations of epinephrine. Because of the technical difficulties of simultaneously measuring portal blood and sampling blood frequently, studies were repeated in six additional subjects using noninvasive image-guided flowmetry to measure percentage changes in hepatic portal blood flow during catecholamine infusion. Norepinephrine reduced hepatic portal blood flow significantly at the low-physiological concentration by 12% (P < .05) and at the pathophysiological concentration by 18% (P < .05). In summary, (1) both epinephrine and norepinephrine were associated with significant ketotic effects at physiological plasma concentrations; and (2) when infused at pathophysiological concentrations, only norepinephrine exerted a significant additional ketotic effect. Since norepinephrine has a significant simultaneous effect of reducing hepatic portal blood flow, we conclude that previous studies may have underestimated the effect of norepinephrine on hepatic ketogenesis.

Adult↗
PubMed1996

Geographical variation in the referral of patients with chronic end stage renal failure for renal replacement therapy.

The number of dialysis units per million population is low in the UK by comparison with other European countries, and this may affect the referral of patients for renal replacement therapy. We used a Poisson regression model to analyse the spatial distribution of all 539 adult patients resident in south-west Wales (Dyfed and West Glamorgan) who started chronic renal replacement therapy between April 1985 and March 1994. Controlling for patient age, population distribution, socio-economic variables and ethnic group, there was a significant negative relationship between referral rates and distance of residence from the renal unit for patients aged over 60 years, but not for younger patients. The prevalence of renal replacement therapy rose from 128 to 454 per million in Dyfed, and from 188 to 647 per million in West Glamorgan, between 1985 and 1995.

Adolescent↗
PubMed1996

Prevalence and correlates of snoring and observed apneas in 5,201 older adults.

The objectives of this study were to describe the prevalence of snoring, observed apneas, and daytime sleepiness in older men and women, and to describe the relationships of these sleep disturbances to health status and cardiovascular diseases (CVD). A cross-sectional design was employed to study sleep problems, CVD, general health, psychosocial factors, and medication use. The subjects were participants in the Cardiovascular Health Study, which included 5,201 adults, aged 65 and older, who were recruited from a random sample of Medicare enrollees in four U.S. communities. Study measures employed were sleep questions, echocardiography, carotid ultrasound, resting electrocardiogram, cognitive function, cardiopulmonary symptoms and diseases, depression, independent activities of daily living (IADLs), and benzodiazepine use. Thirty-three percent of the men and 19% of the women reported loud snoring, which was less frequent in those over age 75. Snoring was positively associated with younger age, marital status, and alcohol use in men, and obesity, diabetes, and arthritis in women. Snoring was not associated, however, with cardiovascular risk factors or clinical CVD in men or women. Observed apneas were reported much less frequently (13% of men and 4% women) than snoring, and they were associated with alcohol use, chronic bronchitis, and marital status in men. Observed apneas were associated with depression and diabetes in women. In both men and women, daytime sleepiness was associated with poor health, advanced age, and IADL limitations. The conclusions of the study were that loud snoring, observed apneas, and daytime sleepiness are not associated cross-sectionally with hypertension or prevalent CVD in elderly persons.

Activities of Daily Living↗
PubMed1996

Insulin resistance limits glucose utilization and exercise tolerance in myophosphorylase deficiency and NIDDM.

Myophosphorylase deficiency [McArdle's disease (MD)] produces a defect in muscle glycogenolysis in which muscular work is limited by delivery of external sources of substrate, primarily glucose and nonesterified fatty acids, to meet energy demands associated with exercise. In the present study, we evaluated an unusual patient with both MD and non-insulin-dependent diabetes mellitus. We hypothesized that insulin resistance would limit transport of extracellular glucose to skeletal muscle during exercise, resulting in impaired exercise performance that was reversible by insulin infusion. The effect of a hyperinsulinemic "euglycemic" clamp on exercise tolerance was evaluated by in vivo 31P-magnetic resonance spectroscopy as well as total work performed. We observed that insulin infusion significantly increased the rate of systemic glucose utilization (P < 0.01) and also significantly decreased the ratio of inorganic phosphate to phosphocreatine (P < 0.001) during forearm exercise compared with the control study. Insulin clamp was also associated with an increase in total work performed (56%) during exercise. Our findings demonstrate that resistance to the biological actions of insulin, as occurs in type II diabetes mellitus, leads to a defect in glucose transport that limits the availability of extracellular glucose to exercising muscle. In our subject with a substrate-limited skeletal muscle metabolism (MD), reversal of this defect in insulin-dependent glucose transport by a hyperinsulinemic euglycemic clamp was associated with significant improvement in magnetic resonance spectroscopy parameters of skeletal muscle metabolism as well as exercise performance.

Diabetes Mellitus, Type 2↗
PubMed1995

Brain glucose uptake and unawareness of hypoglycemia in patients with insulin-dependent diabetes mellitus.

BACKGROUND: In patients with insulin-dependent diabetes mellitus (IDDM) whose treatment results in nearly normal mean plasma glucose concentrations, an unawareness of hypoglycemia can develop, and such patients are at increased risk for seizures and coma. We tested the hypothesis that during hypoglycemia, these patients would have normal glucose uptake in the brain and that consequently no sympathoadrenal activation would begin, resulting in an unawareness of hypoglycemia. METHODS: We measured glucose uptake in the brain at plasma glucose concentrations of 105 and 54 mg per deciliter (5.8 and 3.0 mmol per liter) in 24 patients with IDDM, stratified into three groups according to their glycosylated hemoglobin values (mean [+/- SD] values, 7.2 +/- 0.5, 8.5 +/- 0.4, and 10.2 +/- 1.3 percent) and compared the values for brain glucose uptake with those measured in 15 normal subjects at plasma glucose concentrations of 85 and 55 mg per deciliter (4.2 and 3.1 mmol per liter). We also recorded the subjects' hypoglycemic-symptom scores and measured their plasma concentrations of counterregulatory hormones. RESULTS: There was no significant change in the uptake of glucose in the brain (calculated as the uptake during hypoglycemia minus the uptake during normoglycemia) among the patients with IDDM who had the lowest glycosylated hemoglobin values (+0.6 +/- 2.0 mg [3.3 +/- 11.1 mumol] per 100 g of brain tissue per minute, P = 0.39). Conversely, glucose uptake in the brain fell in both the group with intermediate values (a decrease of 1.3 +/- 1.0 mg [7.2 +/- 5.6 mumol] per 100 g per minute, P = 0.009) and the group with the highest values (a decrease of 1.8 +/- 1.6 mg [10.0 +/- 9.0 mumol] per 100 g per minute, P = 0.01), as it did in the normal subjects (a decrease of 1.6 +/- 1.8 mg [9.0 +/- 10.1 mumol] per 100 g per minute, P = 0.003). The responses of plasma epinephrine and pancreatic polypeptide and the frequency of symptoms of hypoglycemia were lowest in the group with the lowest glycosylated hemoglobin values. CONCLUSIONS: During hypoglycemia, patients with IDDM who have nearly normal glycosylated hemoglobin values have normal glucose uptake in the brain, which preserves cerebral metabolism, reduces the responses of counterregulatory hormones, and causes an unawareness of hypoglycemia.

Adult↗
PubMed1995

Service class migration in England and Wales, 1980-81: identifying gender-specific mobility patterns.

"Gendered patterns of service class migration were observed between the metropolitan counties and regional remainders within England and Wales using 1981 Census data. Observed flows were analysed in terms of the north-south migration divide and counterurbanization, and were compared to estimates derived from gravity models. More service class men than expected moved from metropolitan to non-metropolitan areas and between non-metropolitan areas. Women were less likely to move into non-metropolitan areas and were especially attracted to metropolitan destinations, notably London. These women were also more mobile within the South than service class men. It is suggested that these contrasting patterns reflect the differential geography of women's employment." (SUMMARY IN FRE AND GER)

Demography↗