A randomized trial of thermal ablative therapy versus expandable metal stents in the palliative treatment of patients with esophageal carcinoma

BACKGROUND

Expandable metal stent insertion and thermal tumor ablation (TTA) both improve dysphagia in patients with advanced esophageal cancer, but no direct comparison study of their efficacy on health-related quality of life has been published. The aim of this study was to compare survival, relief of dysphagia, quality of life, and cost in patients treated by thermal ablation or stent insertion.

METHODS

Sixty-five patients with histologically proven, inoperable esophageal and esophagogastric cancer were initially assessed by endoscopy, barium contrast radiography, and CT of the thorax and abdomen. Dysphagia and quality of life were serially assessed at monthly intervals. Patients were randomized to either repeated TTA or insertion of an expandable metal stent.

RESULTS

Median survival was significantly longer for patients who underwent TTA; 125 days (17-546) versus 68 days (8-602) for those in whom a stent was inserted (p < 0.05), although relief of dysphagia was disappointing in both groups. Several patients in both groups had serious treatment-related complications and required further therapy. Median length of hospital stay and cost were greater for patients treated by TTA. Health-related quality of life was globally impaired in both groups at randomization and deteriorated significantly in the stent group. Pain was reported more commonly by patients with stents.

CONCLUSIONS

The palliation of patients with advanced esophageal and esophagogastric cancer remains unsatisfactory. Health-related quality of life deteriorated in the stent group but not in the TTA group. Patients treated by TTA live longer than patients treated by stent insertion, but the cost of TTA is higher.

Uses and abuses of meta-analysis

Meta-analysis, the statistical combination of results from several studies to produce a single estimate of the effect of a treatment, continues to attract controversy. We illustrate the potentials and pitfalls of meta-analysis of controlled clinical trials. Cumulative meta-analysis demonstrates that this technique could prevent delays in the introduction of effective treatments. Meta-analyses are, however, liable to numerous biases both at the level of the individual trial ('garbage in, garbage out') and the dissemination of trial results (publication bias). We argue that meta-analysis should be performed only within the framework of systematic reviews--that is, reviews prepared using a systematic approach to minimise bias and address the combinability of studies.

Measurements of field enhancement introduced by a local electrode

Direct measurements of field enhancement introduced by a local electrode have been carried out on a scanning atom probe (SAP). The results show that an enhancement factor of more than 2 can be obtained simply by reducing the specimen-to-electrode distance from 1.5 mm to 10 microm. Further enhancement can be achieved if the electrode has a smaller aperture. This suggests that a specimen with tip radius of approximately 200 nm, which usually is too blunt to be analysed in a standard atom probe, could now be analysed by SAP. The capability of analysing blunt tips will expand the applicability of SAP to a much broader range of materials.

In vitro maturation of oocytes

In vitro maturation (IVM) of human oocytes is an emerging assisted reproductive technology with great promise. To be successful, this process must entail both nuclear and cytoplasmic maturation. Endogenous regulation of oocyte maturation is a complex sequence of events regulated by endocrine parameters, oocyte/follicular cross-talk, and intra-oocyte kinase/phosphatase interactions. Although nuclear maturation during human oocyte IVM progresses normally, cytoplasmic maturation is significantly lacking, as exemplified by poor embryonic developmental competence and pregnancy rates. Advances made in immature oocyte isolation and oocyte and embryo culture conditions have increased the clinical feasibility of IVM. However, in order to achieve acceptable birth rates, future studies should focus on characterization and regulation of oocyte cytoplasmic maturation, and how oocyte-derived factors influence zygotic genome activation and embryonic developmental competence.

Mode locking in a periodically forced integrate-and-fire-or-burst neuron model

The minimal "integrate-and-fire-or-burst" (IFB) neuron model reproduces the salient features of experimentally observed thalamocortical relay neuron response properties, including the temporal tuning of both tonic spiking (i.e., conventional action potentials) and post-inhibitory rebound bursting mediated by the low-threshold Ca2+ current, I(T). In previous work focusing on experimental and IFB model responses to sinusoidal current injection, large regions of stimulus parameter space were observed for which the response was entrained to periodic applied current, resulting in repetitive burst, tonic, or mixed (i.e., burst followed by tonic) responses. Here we present an exact analysis of such mode-locking in the integrate-and-fire-or-burst model under the influence of arbitrary periodic forcing that includes sinusoidally driven responses as one case. In this analysis, the instabilities of mode-locked states are identified as both smooth bifurcations of an associated firing time map and nonsmooth bifurcations of the underlying discontinuous flow. The explicit construction of borders in parameter space that define the instabilities of mode-locked zones is used to build up the Arnol'd tongue structure for the model. The zones for mode-locking are shown to be in excellent agreement with numerical simulations and are used to explore the observed stimulus dependence of burst versus tonic response of the IFB neuron model.

The relation between questions indicating transient ischaemic attack and stroke in 20 years of follow up in men and women in the Renfrew/Paisley Study

STUDY OBJECTIVE

Transient ischaemic attack (TIA) is often a precursor to stroke, so identification of people experiencing TIA could assist in stroke prevention by indicating those at high risk of stroke who would benefit most from intervention for other stroke risk factors. The objective of this study was to investigate whether answers to a simple questionnaire for TIA could predict the occurrence of stroke in the following 20 years.

DESIGN

Prospective cohort study, conducted between 1972 and 1976, with 20 years of follow up.

SETTING

Renfrew and Paisley, Scotland.

PARTICIPANTS

7052 men and 8354 women aged 45-64 years at the time of screening completed a questionnaire and attended a physical examination. The questionnaire asked participants if they had ever, without warning, suddenly lost the power of an arm, suddenly lost the power of a leg, suddenly been unable to speak properly or suddenly lost consciousness. These four questions were taken as indicators of TIA and were related to subsequent stroke mortality or hospital admission.

MAIN RESULTS

For women, each question was significantly related to stroke risk, whereas for men only the question on loss of power of arm was significantly related to stroke risk. Men and women answering two or more questions positively had double the relative rate of stroke compared with men and women answering none of the questions positively, even after adjusting for other risk factors for stroke.

CONCLUSIONS

A simple questionnaire for TIA could help predict stroke over 20 years of follow up. Targeting men and women who report TIA with early treatment could help to prevent strokes from occurring.

Blood pressure reactions to acute psychological stress and future blood pressure status: a 10-year follow-up of men in the Whitehall II study

OBJECTIVE

The aim of this study was to examine whether blood pressure reactions to mental stress predicted future blood pressure and hypertension.

METHODS

Blood pressure was recorded at an initial medical screening examination after which blood pressure reactions to a mental stress task were determined. A follow-up screening assessment of blood pressure and antihypertensive medication status was undertaken 10 years later. Data were available for 796 male public servants, between 35 and 55 years of age upon entry to the study.

RESULTS

Systolic blood pressure reactions to mental stress were positively correlated with follow-up screening systolic blood pressure and to a lesser extent, follow-up diastolic pressure. In multivariate tests, by far the strongest predictors of follow-up blood pressures were initial screening blood pressures. In the case of follow-up systolic blood pressure, systolic reactions to stress emerged as an additional predictor of follow-up systolic blood pressure. With regard to follow-up diastolic blood pressure, reactivity did not enter the analogous equations. The same outcomes emerged when the analyses were adjusted for medication status. When hypertension at 10-year follow-up was the focus, both systolic and diastolic reactions to stress were predictive. However, with correction for age and initial screening blood pressure, these associations were no longer statistically significant.

CONCLUSIONS

The results of this study provide modest support for the hypothesis that heightened blood pressure reactions to mental stress contribute to the development of high blood pressure. At the same time, they question the clinical utility of stress testing as a prognostic device.

Are women more sensitive to smoking than men? Findings from the Renfrew and Paisley study

BACKGROUND

Prescott et al. found that the relative risks associated with smoking for respiratory and vascular deaths were higher for women who inhale than for inhaling men, and found no gender differences in relative risks of smoking-related cancers. The purpose of the present study was to assess whether these findings are reproducible, using data from the Renfrew and Paisley study.

METHODS

Age-standardized mortality rate differences and age-adjusted mortality rate ratios (using Cox's proportional hazard model) were calculated for male and female smokers by amount smoked compared with never smokers. These analyses were repeated after excluding non-inhalers.

RESULTS

The all-cause mortality rate ratio was higher for men than for women in all categories of amount smoked, although this difference was only statistically significant in the light smokers (1.83 [95% CI : 1.61-2.07] for men and 1.41 [95% CI : 1.28-1.56] for women, P = 0.001). The cause-specific mortality rate ratios tended to be higher for men than for women, and this difference was most substantial for neoplasms (2.57 [95% CI : 2.01-3.29] for male light smokers and 1.35 [95% CI : 1.14-1.61] for female light smokers, P < 0.001) and, in particular, for lung cancer (11.10 [95% CI : 5.89-20.92] for male light smokers and 4.73 [95% CI : 2.99-7.50] for female light smokers, P = 0.03). Furthermore, looking at the rate differences the effects of smoking were uniformly greater in men than in women. These results were virtually unchanged after excluding non-inhalers.

CONCLUSION

We found similar results to Prescott et al. when all smokers were considered, but could not reproduce their findings when non-inhalers were excluded. Given the fact that we showed greater rate differences in men than in women, we think that it is too early to conclude that women may be more sensitive than men to some of the deleterious effects of smoking.

The metabolic, catecholamine and cardiovascular effects of exercise in human sympathetic denervation

The cardiovascular and metabolic responses to supine leg exercise were measured in 9 healthy subjects (controls) and in 19 subjects with two primary forms of autonomic failure (11 with peripheral sympathetic denervation [pure autonomic failure; PAF], 8 with central sympathetic failure [multiple system atrophy; MSA]). With exercise, blood pressure increased in controls and fell markedly in subjects with PAF and MSA. Blood pressure returned to baseline in controls, but remained low in the PAF and MSA groups. With exercise, heart rate increased more in controls than the PAF and MSA groups. Resting plasma noradrenaline concentrations in controls and in subjects with MSA were similar, but were lower in subjects with PAF. With exercise, plasma noradrenaline concentrations increased in controls and were unchanged in subjects with PAF; there was no significant increase in the MSA group. Resting plasma lactate, pyruvate and lactate/pyruvate ratios were similar in all three groups. With exercise, lactate concentrations increased until 2 minutes post exercise in all groups. Pyruvate concentrations after 9 minutes' exercise were higher in controls than in the PAF group but were similar to the MSA group; thereafter, concentrations increased similarly in all groups. The lactate/pyruvate ratio increased until 2 minutes post exercise in all groups. Resting plasma free fatty acids, and beta-hydroxybutyrate were similar in all groups. Plasma glycerol concentrations in control and MSA subjects were similar; concentrations were lower in PAF subjects. With exercise, plasma free fatty acids and glycerol concentrations remained unchanged in all groups; beta-hydroxybutyrate concentrations decreased less in control subjects than in PAF and MSA subjects. In conclusion, there were similar concentrations of plasma free fatty acids, glycerol and beta-hydroxybutyrate in control, PAF and MSA subjects; this could indicate up-regulation of beta-receptors in AF, or that sympathetic activity plays a smaller role in lipolysis. Plasma lactate and pyruvate concentrations increased similarly in all groups, despite marked differences in BP; this suggested an impairment of production or clearance of lactate in AF. A role for lactate-induced vasodilatation, not compensated for by sympathetic vasoconstriction, remains speculative.

Characterisation of a human acid-sensing ion channel (hASIC1a) endogenously expressed in HEK293 cells

Acid-sensing ion channels (ASICs) are a new and expanding family of proton-gated cation (Na+/Ca2+) channels that are widely expressed in sensory neurons and the central nervous system. Their distribution suggests that they may play a critical role in the sensation of the pain that accompanies tissue acidosis and may also be important in detecting the subtle pH variations that occur during neuronal signalling. Here, using whole-cell patch-clamp electrophysiology and reverse transcriptase-polymerase chain reaction (RT-PCR), we show that HEK293 cells, a commonly used cell line for the expression and characterisation of many ion channels, functionally express an endogenous proton-gated conductance attributable to the activity of human ASIC1a. These data therefore represent the first functional characterisation of hASIC1 and have many important implications for the use of HEK293 cells as a host cell system for the study of ASICs, vanilloid receptor-1 and any other proton-gated channel. With this latter point in mind we have devised a simple desensitisation strategy to selectively remove the contribution of hASIC1a from proton-gated currents recorded from HEK293 cells expressing vanilloid receptor-1.

The socioeconomic position of employed women, risk factors and mortality

Many studies have demonstrated the graded association between socioeconomic position and health. Few of these studies have examined the cumulative effect of socioeconomic position throughout the lifecourse, and even fewer have included women. Those that have explored gender differences affirm the importance of studying the factors that predict women and men's health separately. This study addresses the associations between cross-sectional and longitudinal socioeconomic position, risk factors for cardiovascular disease and mortality from various causes. Analyses are based on data from a cohort of working Scottish women recruited between 1970 and 1973. Five socioeconomic measures were explored in relation to diastolic blood pressure, plasma cholesterol concentration, body mass index, forced expiratory volume in 1 s (FEV1). amount of recreational exercise taken, cigarette smoking and alcohol consumption. In general, for each of the five measures of socioeconomic position, there were significant differences in at least one of the age-adjusted physiological risk factors for cardiovascular disease (diastolic blood pressure, plasma cholesterol concentration, body mass index, FEV1). There were also significant differences in the percentage of current cigarette smokers according to different measures of socioeconomic position, although this was not the case for the other behavioural risk factors for cardiovascular disease (amount of recreational exercise taken, and alcohol consumption). Measures of socioeconomic position were also examined in relation to cause of death for the women who died before 1 January 1999. After adjusting for age and risk factors, a composite measure of lifetime socioeconomic experience was a more potent predictor of all cause mortality and mortality from cardiovascular disease than other measures of socioeconomic position. It therefore seems that conventional measurcs of socioeconomic position, estimated at one point in time, do not adequately capture the effects of socioeconomic circumstances on the risk of mortality among employed women. Thus, a broader range of explanatory factors for mortality differentials than currently exists must be considered, and must include consideration of factors operating throughout the lifecourse.

Phase changes in T(3)R(3)(f) human insulin: temperature or pressure induced?

The structure of T(3)R(3) hexameric human insulin has been determined at 100 K from two different crystals at 1.2 and 1.3 A resolution and refined to residuals of 0.169 and 0.176, respectively. Owing to a phase change, the c axis is double its room-temperature value and the asymmetric unit contains two independent TR(f) insulin dimers. Compared with the orientation in the room-temperature structure, one dimer undergoes a rotation about the c axis of -5 degrees, while the second is rotated +4 degrees. A superposition of the backbone atoms of the two independent dimers shows that the C(alpha) atoms of five residues within the R(f)-state monomers are displaced by more than 1.0 A; smaller displacements are observed for the T-state monomers. Four zinc ions lie on the crystallographic threefold axis and each forms bonds to three symmetry-related HisB10 N(varepsilon2) atoms from the T- and R(f)-state trimers. While three of the zinc ions are tetrahedrally coordinated with a chloride ion completing the coordination sphere, mixed tetrahedral/octahedral coordination is observed for one of the T-state zinc ions. The three symmetry-related "phenolic binding sites" in one hexamer contain water molecules and a glycerol molecule, but the same sites in the second hexamer are occupied by a zinc ion coordinated to an alternate conformation of HisB10, a symmetry-related HisB5 and two chloride ions. Two additional and partially occupied zinc ion sites are observed at the interface between the two independent dimers. One zinc ion is coordinated by a T-state HisB5 of one dimer, an R-state HisB5 of the second dimer and two water molecules; the second zinc ion is coordinated by an alternate side-chain conformation of the T-state HisB5 and three water molecules. The carboxyl group of one GluB13 side chain, which exists in two discrete conformations, appears to be protonated, because short contacts exist to a second carboxyl group or to a carbonyl O atom.

Social capital, disorganized communities, and the third way: understanding the retreat from structural inequalities in epidemiology and public health

The construct of social capital has recently captured the interest of researchers in social epidemiology and public health. The authors review current hypotheses on the social capital and health link, and examine the empirical evidence and its implications for health policy. The construct of social capital employed in the public health literature lacks depth compared with its uses in social science. It presents itself as an alternative to materialist structural inequalities (class, gender, and race) and invokes a romanticized view of communities without social conflict that favors an idealist psychology over a psychology connected to material resources and social structure. The evidence on social capital as a determinant of better health is scant or ambiguous. Even if confirmed, such hypotheses call for attention to social determinants beyond the proximal realm of individualized sociopsychological infrastructure. Social capital is used in public health as an alternative to both state-centered economic redistribution and party politics, and represents a potential privatization of both economics and politics. Such uses of social capital mirror recent "third way" policies in Germany, the United Kingdom, and United States. If third way policies lose support in Europe, the prominence of social capital there might be short lived. In the United States, where the working class is less likely to influence social policy, interest in social capital could be longer lived or could drift into academic limbo like other psychosocial constructs once heralded as the next big idea.

Income inequality, the psychosocial environment, and health: comparisons of wealthy nations

BACKGROUND

The theory that income inequality and characteristics of the psychosocial environment (indexed by such things as social capital and sense of control over life's circumstances) are key determinants of health and could account for health differences between countries has become influential in health inequalities research and for population health policy.

METHODS

We examined cross-sectional associations between income inequality and low birthweight, life expectancy, self-rated health, and age-specific and cause-specific mortality among countries providing data in wave III (around 1989-92) of the Luxembourg Income Study. We also used data from the 1990-91 wave of the World Values Survey (WVS). We obtained life expectancy, mortality, and low birthweight data from the WHO Statistical Information System.

FINDINGS

Among the countries studied, higher income inequality was strongly associated with greater infant mortality (r=0.69, p=0.004 for women; r=0.74, p=0.002 for men). Associations between income inequality and mortality declined with age at death, and then reversed among those aged 65 years and older. Income inequality was inconsistently associated with specific causes of death and was not associated with coronary heart disease (CHD), breast or prostate cancer, cirrhosis, or diabetes mortality. Countries that had greater trade union membership and political representation by women had better child mortality profiles. Differences between countries in levels of social capital showed generally weak and somewhat inconsistent associations with cause-specific and age-specific mortality.

INTERPRETATION

Income inequality and characteristics of the psychosocial environment like trust, control, and organisational membership do not seem to be key factors in understanding health differences between these wealthy countries. The associations that do exist are largely limited to child health outcomes and cirrhosis. Explanations for between-country differences in health will require an appreciation of the complex interactions of history, culture, politics, economics, and the status of women and ethnic minorities.

Milk, coronary heart disease and mortality

STUDY OBJECTIVE

To study the association between reported milk consumption and cardiovascular and all cause mortality.

DESIGN

A prospective study of 5765 men aged 35-64 at the time of examination.

SETTING

Workplaces in the west of Scotland between 1970 and 1973.

PARTICIPANTS

Men who completed a health and lifestyle questionnaire, which asked about daily milk consumption, and who attended for a medical examination.

MAIN RESULTS

150 (2.6%) men reported drinking more than one and a third pints a day, Some 2977 (51.6%) reported drinking between a third and one and a third pints a day and 2638 (45.8%) reported drinking less than a third of a pint a day. There were a total of 2350 deaths over the 25 year follow up period, of which 892 deaths were attributed to coronary heart disease. The relative risk, adjusted for socioeconomic position, health behaviours and health status for deaths from all causes for men who drank one third to one and a third pints a day versus those who drank less than a third of a pint was 0.90 (95% CI 0.83, 0.97). The adjusted relative risk for deaths attributed to coronary heart disease for men who drank one third to one and a third pints a day versus those who drank less than one third of a pint was 0.92 (95% CI 0.81, 1.06).

CONCLUSIONS

No evidence was found that men who consumed milk each day, at a time when most milk consumed was full fat milk, were at increased risk of death from all causes or death from coronary heart disease.