The vanilloid receptor (VR1)-mediated effects of anandamide are potently enhanced by the cAMP-dependent protein kinase

The endogenous cannabinoid receptor ligand, anandamide (AEA), is a full agonist of the vanilloid receptor type 1 (VR1) for capsaicin. Here, we demonstrate that the potency and efficacy of AEA at VR1 receptors can be significantly increased by the concomitant activation of protein kinase A (PKA). In human embryonic kidney (HEK) cells over-expressing human VR1, AEA induces a rise in cytosolic Ca(2+) concentration that is mediated by this receptor. The EC(50) for this effect was decreased five-fold in the presence of forskolin (FRSK, 1-5 microM) or the cAMP analogue, 8-Br-cAMP (10-100 microM). The effects of 8-Br-cAMP and FRSK were blocked by a selective PKA inhibitor. The FRSK (10 nM) also potently enhanced the sensory neurone- and VR1-mediated constriction by AEA of isolated guinea-pig bronchi, and this effect was abolished by a PKA inhibitor. In rat dorsal root ganglia slices, AEA-induced release of substance P, an effect mediated by VR1 activation, was enhanced three-fold by FRSK (10 nM). Thus, the ability of AEA to stimulate sensory VR1, with subsequent neuropeptide release, appears to be regulated by the state of activation of PKA. This observation supports the hypothesis that endogenous AEA might stimulate VR1 under certain pathophysiological conditions.

Quantitative detection of aromatic compounds in single aerosol particle mass spectrometry

Most laser-based aerosol mass spectrometers rely on a single ultraviolet laser to both ablate and ionize the aerosol particle. This technique produces complex and fragmented mass spectra, especially for organic compounds. The approach presented here achieves a more robust and quantitative analysis using a CO2 laser to evaporate the aerosol particle and a vacuum ultraviolet laser to ionize the vapor plume. Vacuum ultraviolet laser ionization produces little fragmentation in the mass spectra, making the identification of an aerosol particle's constituents more straightforward. An analysis of simple, three-component mixtures of aniline, benzyl alcohol, and m-nitrotoluene shows that the technique also provides a quantitative analysis for all the components of the mixture. Furthermore, the detection of predominantly parent ion signal from anthracene particles demonstrates the utility of the technique in the analysis of lower vapor pressure, solid-phase aerosols. Finally, we discuss the potential and limitations of this technique in analyzing organic atmospheric aerosols.

Phosphorylation of mitogen-activated protein kinase is regulated by protein kinase C, cyclic 3',5'-adenosine monophosphate, and protein phosphatase modulators during meiosis resumption in rat oocytes

Mitogen-activated protein (MAP) kinase, protein kinase C (PKC), cAMP, and okadaic acid (OA)-sensitive protein phosphatases (PPs) have been suggested to be involved in oocyte meiotic resumption. However, whether these protein kinases and phosphatases act by independent pathways or interact with each other in regulating meiosis resumption is unknown. In the present study, we aimed to determine the regulation of meiosis resumption and MAP kinase phosphorylation by PKC, cAMP, and OA-sensitive PPs in rat oocytes using an in vitro oocyte maturation system and Western blot analysis. We found that ERK1 and ERK2 isoforms of MAP kinases existed in a dephosphorylated (inactive) form in germinal vesicle breakdown (GVBD)-incompetent and GVBD-competent germinal vesicle intact (GVI) oocytes as well as GVBD oocytes at equivalent levels. These results indicate that MAP kinases are not responsible for the initiation of normal meiotic resumption in rat oocytes. However, when GVBD-incompetent and GVBD-competent oocytes were incubated in vitro for 5 h, MAP kinases were phosphorylated (activated) in GVBD-competent oocytes, but not in meiotic-incompetent oocytes, suggesting that oocytes acquire the ability to phosphorylate MAP kinase during acquisition of meiotic competence. We also found that both meiosis resumption and MAP kinase phosphorylation were inhibited by PKC activation or cAMP elevation. Moreover, these inhibitory effects were overcome by OA, which inhibited PP1/PP2A activities. These results suggest that both cAMP elevation and PKC activation inhibit meiosis resumption and MAP kinase phosphorylation at a step prior to OA-sensitive protein phosphatases. In addition, inhibitory effects of cAMP elevation on meiotic resumption and MAP kinase phosphorylation were not reversed by calphostin C-induced PKC inactivation, indicating that cAMP inhibits both meiotic resumption and MAP kinase activation in a PKC-independent manner.

Changes in blood pressure among students attending Glasgow University between 1948 and 1968: analyses of cross sectional surveys

OBJECTIVES

To examine the changes in blood pressure over time in a cohort of young adults attending university between 1948 and 1968.

DESIGN

Cross sectional study.

SETTING

Glasgow University.

PARTICIPANTS

12 414 students aged 16-25 years-9248 men (mean age 19.9 years) and 3164 women (19.2 years)-who participated in health screening on entering university between 1948 and 1968.

MAIN OUTCOME MEASURES

Systolic and diastolic blood pressure.

RESULTS

In male students mean systolic blood pressure adjusted for age decreased from 134.5 (95% confidence interval 133.8 to 135.2) mm Hg in those born before 1929 to 125.7 (125.0 to 126.3) mm Hg in those born after 1945, and diastolic blood pressure dropped from 80.3 (79.8 to 80.8) mm Hg to 74.7 (74.2 to 75.1) mm Hg. For female students the corresponding declines were from 129.0 (127.5 to 130.5) mm Hg to 120.6 (119.8 to 121.4) mm Hg and from 79.7 (78.7 to 80.6) mm Hg to 77.0 (76.5 to 77.5) mm Hg. Adjustment for potential confounding factors made little difference to these findings. The proportion of students with hypertension declined substantially in both sexes.

CONCLUSIONS

Substantial declines in systolic and diastolic blood pressure over time were occurring up to 50 years ago in young adults who were not taking antihypertensive medication. Since blood pressure tracks into adult life, the results of the cross sectional comparisons suggest that factors acting in early life may be important in determining population risk of cardiovascular disease. Changes in such factors may have made important contributions to the decline in rates of cardiovascular diseases, particularly stroke, seen in developed countries during the past century.

Social class differences in lung cancer mortality: risk factor explanations using two Scottish cohort studies

BACKGROUND

The study investigated differences in lung cancer mortality risk between social classes.

METHODS

Twenty years of mortality follow-up were analysed in 7052 men and 8354 women from the Renfrew/Paisley general population study and 4021 working men from the Collaborative study.

RESULTS

More manual than non-manual men and women smoked, reported morning phlegm, had worse lung function and lived in more deprived areas. Lung cancer mortality rates were higher in manual than non-manual men and women. Significantly higher lung cancer mortality risks were seen for manual compared to non-manual workers when adjusting for age only and adjustment for smoking reduced these risks to 1.41 (95% CI : 1.12-1.77) for men in the Renfrew/Paisley study, 1.28 (95% CI : 0.94-1.75) for women in the Renfrew/Paisley study and 1.43 (95% CI : 1.02-2.01) for men in the Collaborative study. Adjustment for lung function, phlegm and deprivation category attenuated the risks which were of borderline significance for men in the Renfrew/Paisley study and non significant for women in the Renfrew/Paisley study and men in the Collaborative study. Adding extra socioeconomic variables, available in the Collaborative study only, reduced the difference between the manual and non-manual social classes completely.

CONCLUSIONS

There is a difference in lung cancer risk between social classes, in addition to the effect of smoking. This can be explained by poor lung health, deprivation and poor socioeconomic conditions throughout life. As well as anti-smoking measures, reducing socioeconomic inequalities and targeting individuals with poor lung function for help with smoking cessation could help reduce future lung cancer incidence and mortality.

Dietary fat intake and prevention of cardiovascular disease: systematic review

OBJECTIVE

To assess the effect of reduction or modification of dietary fat intake on total and cardiovascular mortality and cardiovascular morbidity.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Library, Medline, Embase, CAB abstracts, SIGLE, CVRCT registry, and biographies were searched; trials known to experts were included.

INCLUDED STUDIES

Randomised controlled trials stating intention to reduce or modify fat or cholesterol intake in healthy adult participants over at least six months. Inclusion decisions, validity, and data extraction were duplicated. Meta-analysis (random effects methodology), meta-regression, and funnel plots were performed.

RESULTS

27 studies (30 902 person years of observation) were included. Alteration of dietary fat intake had small effects on total mortality (rate ratio 0.98; 95% confidence interval 0.86 to 1.12). Cardiovascular mortality was reduced by 9% (0.91; 0.77 to 1.07) and cardiovascular events by 16% (0.84; 0.72 to 0.99), which was attenuated (0.86; 0.72 to 1.03) in a sensitivity analysis that excluded a trial using oily fish. Trials with at least two years' follow up provided stronger evidence of protection from cardiovascular events (0.76; 0.65 to 0.90).

CONCLUSIONS

There is a small but potentially important reduction in cardiovascular risk with reduction or modification of dietary fat intake, seen particularly in trials of longer duration.

Job insecurity in white-collar workers: toward an explanation of associations with health

This article describes 2 studies that examined changes in psychosocial work characteristics (job strain model) and health-related behaviors as potential explanations of the job insecurity-health relationship in a longitudinal cohort of white-collar British civil servants. Job insecurity arising from anticipation of change was associated with a modest increase in self-reported morbidity, whereas chronic job insecurity was associated with some adverse physiological changes. Anticipation of change and chronic job insecurity were associated with adverse changes in other psychosocial work characteristics, but few changes were significant and consistent across both exposure groups. Changes in health-related behaviors associated with either exposure were slight. Apart from a minor role for social support at work in both sexes and a modest role for job demands in women, adverse changes in these factors explain little of the job insecurity-health relationship.

Employment status and health after privatisation in white collar civil servants: prospective cohort study

OBJECTIVES

To determine whether employment status after job loss due to privatisation influences health and use of health services and whether financial strain, psychosocial measures, or health related behaviours can explain any findings.

DESIGN

Data collected before and 18 months after privatisation.

SETTING

One department of the civil service that was sold to the private sector.

PARTICIPANTS

666 employees during baseline screening in the department to be privatised.

MAIN OUTCOME MEASURES

Health and health service outcomes associated with insecure re-employment, permanent exit from paid employment, and unemployment after privatisation compared with outcomes associated with secure re-employment.

RESULTS

Insecure re-employment and unemployment were associated with relative increases in minor psychiatric morbidity (mean difference 1.56 (95% confidence intervals interval 1.0 to 2.2) and 1.25 (0.6 to 2.0) respectively) and having four or more consultations with a general practitioner in the past year (odds ratio 2.04 (1.1 to 3.8) and 2.39 (1.2 to 4.7) respectively). Health outcomes for respondents permanently out of paid employment closely resembled those in secure re-employment, except for a substantial relative increase in longstanding illness (2.25; 1.1 to 4.4). Financial strain and change in psychosocial measures and health related behaviours accounted for little of the observed associations. Adjustment for change in minor psychiatric morbidity attenuated the association between insecure re-employment or unemployment and general practitioner consultations by 26% and 27%, respectively.

CONCLUSIONS

Insecure re-employment and unemployment after privatisation result in increases in minor psychiatric morbidity and consultations with a general practitioner, which are possibly due to the increased minor psychiatric morbidity.

Inhibition of bacterial RNA polymerase by the cyanobacterial metabolites 12-epi-hapalindole E isonitrile and calothrixin A

The alkaloid 12-epi-hapalindole E isonitrile, from a cyanobacterial Fischerella species, and the indolophenanthridine calothrixin A, from Calothrix, inhibited Escherichia coli RNA polymerase competitively with respect to ATP, and non-competitively with respect to UTP. The inhibition was dependent on the order of addition of the inhibitors. The K(I) values, with ATP as the variable substrate, were 1.3+/-0.2 mM and 0.23+/-0.11 mM, respectively. Based on comparisons with the sensitivity of whole cells to these inhibitors, it is concluded that other targets in addition to RNA polymerase may also be implicated in their action.

Socio-economic position and coronary heart disease risk factors in youth. Findings from the Young Hearts Project in Northern Ireland

BACKGROUND

This study investigates the existence of socioeconomic differentials in behavioural and biological risk factors for coronary heart disease in young people from Northern Ireland, taking into account differences in biological maturation.

METHODS

A school-based prospective study, with measurements in 1989/1990 and 1992/1993. Socio-economic position was based on occupational level of the main family breadwinner. Behavioural risk factors included were physical inactivity, the intake of total energy, dietary fat and a number of micronutrients. Biological risk factors included were blood pressure, body fatness, lipoproteins and cardio-pulmonary fitness. Biological maturation was based on Tanner's stages.

PARTICIPANTS

251 boys and 258 girls who were measured at the age of 12 years and re-examined at the age of 15 years.

RESULTS

Cross-sectional analyses showed that socio-economic differences in cholesterol intake (in boys) and physical inactivity and total energy intake (in girls) were present at 12 and 15 years of age, while differences in fat and fruit intake and smoking behaviour (in boys and girls) became established at the age of 15 years, with unfavourable levels in subjects in the manual group. Longitudinal analyses confirmed that differences in behavioural risk factors exist or develop during adolescence. No clear pattern of differences in biological risk factors was found by socio-economic position. Adjustment for biological maturation did not materially alter the results.

CONCLUSION

Differences in lifestyle by socio-economic position seem to become established in adolescence. These differences however, are not (yet) reflected in differences in biological risk factors by socio-economic position.

Homocysteine and coronary heart disease in the Caerphilly cohort: a 10 year follow up

OBJECTIVE

Prospective assessment of the risk of coronary heart disease associated with total serum homocyst(e)ine (homocysteine) concentration.

DESIGN

Nested case-control study.

SETTING

Caerphilly and surrounding villages in south Wales, UK.

PARTICIPANTS

2290 men who participated in phase II of the study in 1984. After a mean follow up of 10 years, 312 men developed coronary heart disease and were compared with 1248 randomly selected, age frequency matched controls.

MAIN OUTCOME MEASURE

Acute myocardial infarction or death from coronary heart disease.

RESULTS

The geometric mean serum homocysteine concentration was higher in cases (12.2 micromol/l, 95% confidence interval (CI) 11.8 to 12.6 micromol/l) than in controls (11.8 micromol/l, 95% CI 11.3 to 12.5 micromol/l) (p = 0.09). There was a graded increase in the odds ratio of coronary heart disease across quintiles of the homocysteine concentration distribution compared with the first (p = 0.04), which was attenuated when adjusted for confounding variables (p = 0.4). There was a small but non-significant increase in the adjusted odds ratio of coronary heart disease per standard deviation change in the log distribution of homocysteine concentration (OR = 1.07 (95% CI.93 to 1.24), p = 0.34). Comparing the top quintile of the homocysteine concentration with the remaining 80%, the adjusted odds ratio of coronary heart disease was 1.03 (95% CI 0.73 to 1.45) (p = 0.8) and comparing the top 5% with the remaining 95% it was 1.05 (95% CI 0.56 to 1.95) (p = 0.9).

CONCLUSIONS

These findings do not support the hypothesis that a raised homocysteine concentration is a strong independent risk factor for coronary heart disease. Randomised controlled trials of homocysteine lowering treatment such as folic acid are needed before generalizing the early positive results of observational studies.

Homocysteine and ischaemic stroke in men: the Caerphilly study

OBJECTIVE

To assess the risk of ischaemic stroke associated with total serum homocyst(e)ine (tHcy) concentration.

DESIGN

Cohort study.

SETTING

Caerphilly, South Wales

PARTICIPANTS

2254 men age 50 to 64 years recruited between 1984 and 1988.

RESULTS

107 men developed ischaemic stroke and mean follow up time was 10.2 years. There was no significant difference in mean serum total homocyst(e)ine levels between stroke cases (12.2 micromol 95% CI 11.6 to 13.1) and non-cases (11.7 micromol 95% CI 11.5 to 11.9) (p=0.14). There was no significant risk for a standard deviation increase in homocyst(e)ine (adjusted hazard ratio = 1.1, 95% CI 0.9 to 1.4). An interaction was observed between homocyst(e)ine and age at entry (p=0.003). The adjusted odds ratio comparing the top quintile of homocyst(e)ine with the rest was 2.5 (95% CI 1.0 to 6.2) for strokes occurring under 65 years and 0.5 (95% CI 0.2 to 1.3) at 65 years or older (p value for interaction =0.02). Risk also differed by blood pressure status. The adjusted hazard ratio for a standard deviation increase in homocyst(e)ine was 0.8, (95% CI 0.6 to 1.2) for normotensive men and 1.3 (95% CI 1.1 to 1.7) for hypertensive men (p value for interaction =0.01).

CONCLUSIONS

Overall, there is no significant relation between homocyst(e)ine and ischaemic stroke in this cohort. However, its aetiological importance may be greater for premature ischaemic strokes (<65 years) and in hypertensive men.

Identification and characterization of the gene encoding human cytoplasmic polyadenylation element binding protein

The maturation of human oocytes occurs in the absence of gene transcription. In model organisms, such as Drosophila, Xenopus, and the mouse, oocyte maturation and early pattern formation is mediated through the regulated translation of maternally derived mRNAs. The maturation-dependent stimulation of maternal mRNA translation is correlated with increases in poly(A) tail length, controlled through a process termed cytoplasmic polyadenylation. However, this mechanism of mRNA translational control has not been characterized in humans. In this study we report the cloning of a human cytoplasmic polyadenylation element binding (hCPEB) protein with sequence-specific RNA binding activity. Our data demonstrate that alternative splicing generates hCPEB mRNAs that encode proteins with a conserved C-terminal RNA binding domain but with different N-terminal regulatory domains. The hCPEB mRNA is expressed in the brain and heart as well as in immature oocytes, consistent with the hypothesis that cytoplasmic polyadenylation may regulate the translation of human mRNAs in both oocytes and somatic cells.

Age at menarche: secular trends and association with adult anthropometric measures

BACKGROUND

Age at menarche has been used as a marker of environmental conditions during childhood. Previous work has shown trends of decreasing age at menarche throughout the 19th century, but reported trends in the 20th century have been less consistent. The nature of the relationship between age at menarche and adult life anthropometric measures may be important in understanding the importance of this measure on disease in later life.

AIM

To establish whether mean age at menarche changed during the first half of the 20th century, and to determine the nature of associations between age at menarche and anthropometric measures in young adulthood.

SUBJECTS AND METHODS

3433 female students, who were born between 1919 and 1952 and who attended health checks at the student health service of the University of Glasgow between 1948 and 1968.

RESULTS

Mean age at menarche decreased from 13.2 years in the earliest born to 12.5 years in the latest born students. These results were not explained by changes in socio-demographic factors. Menarcheal age was positively associated with height and negatively associated with weight and BMI, results independent of socio-demographic and behavioural factors.

CONCLUSIONS

The falling age at menarche described here may be related to nutritional influences in the first half of the 20th century. The influence of menarche on BMI in early adulthood may have important health consequences.