Interferometric sensor for detection of surface-bound bioreactions

An integrated optical interferometer for direct detection of affinity reactions is presented. A modern version of a Young's interferometer is built with a waveguide structure as beam splitter and as sensing element. Resistive waveguides were produced by plasma-enhanced chemical vapor deposition of silicon oxinitride. At the output of this device a fringe pattern is detected by a CCD line camera. The adsorption of molecules on top of the waveguides is observed with a detection limit of 750 fg/mm(2). The resolvable variation of effective refractive index is 9 x 10(-8).

[Atrial natriuretic peptide as an indicator of mild postoperative cardiac dysfunction after uncomplicated bypass surgery]

Plasma levels of ANP (pg/ml; radioimmunoassay) as a parameter for postischemic dysfunction and levels of Troponin T (TnT) (ng/ml; ELISA test) as a parameter for postischemic cellular damage were determined in 15 patients with coronary artery disease (CAD) (mean age: 58 +/- 6.1 years; 13 m, 2 w; with no history of myocardial infarction and no signs for congestive heart failure) prior to, during and after extracorporal circulation (ECC). Under standardized conditions during the ECC basic parameters concerning the cardial hemodynamic (heart rate (HR); systolic (RRsys, mmHg), diastolic pressure (RR dia, mmHg) central venous pressure (CVP, mmHg); left atrial pressure (LAP, mmHg); left ventricular enddiastolic pressure (LVEDP, mmHg)) and ECG monitoring blood samples were performed: 1) prior to operation (op); 2) prior to CPB; 3) 1 h CPB; 4) 5 min after CPB; 5) 1 h after CPB; 6) 6 h postoperative (postop); 7) 24 h postop; 8) 48 h postop; 9) 10 days postop. Also the left atrial diameter (LAD, mm) and the left ventricular enddiastolic diameter at Q (LVEDD, mm) pre- and postop were documented with m-mode echocardiography (Echo) and ejection fraction (EF, %) was calculated. The bypass operations were performed with intermittent aortic cross-clamping with open venae cavae (CVP: 0-5 mmHg) and moderate hypothermia. For the determination of ANP levels and TnT levels in arterial and venous blood, a double-antibody (AB) radioimmunoassay and an ELISA test were used. Concerning the patients with CAD there was a maximal increase of ANP from preoperative 90 +/- 10 (M +/- SEM) pg/ml (p < 0.05) up to intraoperative 380 +/- 38 pg/ml. Ten days postop, the ANP level was with 262 +/- 33 pg/ml still increased threefold in comparison to the preoperative level. TnT showed an increase from preoperative 0.02 +/- 0.01 ng/ml up to intraoperative 3.44 +/- 0.47 ng/ml. Ten days postop the TnT concentration was at the preoperative level with 0.13 +/- 0.11 ng/ml. Five minutes after bypass up to 48 h postop, ANP and TnT levels were correlated (p < 0.05, r = 3.4). There was an increase of the LAD from preoperative 42.2 +/- 1.1 mm up to 46.8 +/- 1.2 mm (p < 0.05) 10 days postop as determined by m-mode echo. LVEDD and EF changed from preoperative 51.1 +/- 0.9 mm and 73 +/- 2% to 54.5 +/- 1.2 mm and 65 +/- 4% 10 days postop. The significant increase of TnT (172-fold) indicates the cellular, myocardial injury, caused by the operation without signs in ECG recordings and no signs of congestive heart failure. The significantly increased ANP level up to the 10th day postop indicate sa very sensitive prolonged, postischemic dysfunction, which is not compensated 10 days postop.

Risk for diabetes mellitus in middle-aged Caucasian male participants of the PROCAM study: implications for the definition of impaired fasting glucose by the American Diabetes Association. Prospective Cardiovascular Münster

The criteria of the American Diabetes Association and the WHO for the diagnosis of diabetes mellitus are controversially discussed. In a prospective population study, we evaluated the data of 3,737 men, aged 36-60 yr, without diabetes mellitus and with fasting serum glucose levels less than 7 mmol/L at entry into the study who had at least 1 repeat examination during a follow-up of 4-10 yr. During a mean follow-up of 6.3 yr, 200 men developed diabetes mellitus. They differed significantly from 3,537 men by body mass index, fasting serum levels of glucose, high density lipoprotein cholesterol, and family history positive for diabetes mellitus. Receiver operating curve analysis revealed that a glucose level of 5.72 mmol/L was the best discriminatory cut-off. Upon global risk estimation by multiple logistic function (MLF) analysis, 69.6% of all diabetes mellitus incidences occurred in the highest quintile as defined by the MLF algorithm. The relative risk of a men in this quintile was 8.7 compared to that in the residual population. The performance of risk assessment by MLF as estimated by the area under the receiver operator characteristic curve was similar to fasting glucose levels. Global risk estimation by multiple risk factors does not improve the prediction of diabetes mellitus by fasting glucose in middle-aged men. The lower discriminatory cut-off of 5.72 mmol/L glucose may help to reduce the previously reported discordance between impaired fasting glucose (American Diabetes Association) and impaired glucose tolerance (WHO) in diagnosis of the prediabetic state.

Treatment of hypertriglyceridemia by two diets rich either in unsaturated fatty acids or in carbohydrates: effects on lipoprotein subclasses, lipolytic enzymes, lipid transfer proteins, insulin and leptin

BACKGROUND

There is lack of agreement on which dietary regimen is most suitable for treatment of hypertriglyceridemia, especially if high triglyceride concentrations are not due to obesity or alcohol abuse. We compared the effects on blood lipids of a diet high in total and unsaturated fat with a low-fat diet in patients with triglyceride concentrations of > 2.3 mmol/l.

METHODS

Nineteen non-obese male outpatients with triglycerides ranging from 2.30 to 9.94 mmol/l received two consecutive diets for 3 weeks each: first a modified high-fat diet (39% total fat, 8% SFA, 15% monounsaturated fatty acids, 1.6% marine n-3 polyunsaturated fatty acids), and then a low-fat diet (total fat 28%, carbohydrates 54%).

RESULTS

The high-fat diet significantly decreased triglycerides (-63%), total cholesterol (-22%), VLDL cholesterol (-54%), LDL cholesterol ( 16%), total apoC-III (-27%), apoC-III in apoB containing lipoproteins (apoC-III LpB; -31%) and in HDL (apoC-III nonLpB; -29%), apoE in serum (-33%) and apoB-containing lipoproteins (nonHDL-E; -42%), LpA-I (-16%), insulin (-36%), and leptin (-26%) and significantly increased the means of HDL cholesterol (+8%), LDL size (+6%), lipoprotein lipase (LPL, +11%), hepatic lipase (+13%), and lecithin: cholesterol acyltransferase (LCAT, +2%). The subsequent low-fat diet increased triglycerides (+63%), VLDL cholesterol (+19%), apoC-III (+23%), apoC-III LpB (+44%) apoC-III nonLpB (+17%), apoE (+29%) and nonHDL-E (+43%), and decreased HDL cholesterol (-12%), LPL (-3%), and LCAT (-3%). Changes in triglycerides correlated with changes in LPL activity and insulin levels.

CONCLUSIONS

In hypertriglyceridemic patients, a modified diet rich in mono- and n-3 polyunsaturated fatty acids is more effective than a carbohydrate-rich low-fat diet in correcting the atherogenic lipoprotein phenotype.

Risk for diabetes mellitus in middle-aged Caucasian male participants of the PROCAM study: implications for the definition of impaired fasting glucose by the American Diabetes Association. Prospective Cardiovascular Münster

The criteria of the American Diabetes Association and the WHO for the diagnosis of diabetes mellitus are controversially discussed. In a prospective population study, we evaluated the data of 3,737 men, aged 36-60 yr, without diabetes mellitus and with fasting serum glucose levels less than 7 mmol/L at entry into the study who had at least 1 repeat examination during a follow-up of 4-10 yr. During a mean follow-up of 6.3 yr, 200 men developed diabetes mellitus. They differed significantly from 3,537 men by body mass index, fasting serum levels of glucose, high density lipoprotein cholesterol, and family history positive for diabetes mellitus. Receiver operating curve analysis revealed that a glucose level of 5.72 mmol/L was the best discriminatory cut-off. Upon global risk estimation by multiple logistic function (MLF) analysis, 69.6% of all diabetes mellitus incidences occurred in the highest quintile as defined by the MLF algorithm. The relative risk of a men in this quintile was 8.7 compared to that in the residual population. The performance of risk assessment by MLF as estimated by the area under the receiver operator characteristic curve was similar to fasting glucose levels. Global risk estimation by multiple risk factors does not improve the prediction of diabetes mellitus by fasting glucose in middle-aged men. The lower discriminatory cut-off of 5.72 mmol/L glucose may help to reduce the previously reported discordance between impaired fasting glucose (American Diabetes Association) and impaired glucose tolerance (WHO) in diagnosis of the prediabetic state.

C-reactive protein and the severity of atherosclerosis in myocardial infarction patients with stable angina pectoris

BACKGROUND

Recent findings provide evidence for the importance of inflammatory processes in the pathogenesis of atherosclerosis. C-reactive protein was elevated in patients with peripheral artery disease, coronary heart disease and myocardial infarction compared to normal subjects.

METHODS

In 1112 male and 299 female survivors of myocardial infarction (mean age +/- SD, men, 50.4 +/- 9.5, women, 56.1 +/- 9.3), we investigated whether plasma C-reactive protein concentration is associated with the severity of coronary heart disease and generalized pre-clinical or clinically manifest arteriopathy. The control group consisted of 326 male and 138 female individuals matched for age without clinical symptoms of coronary disease. The severity of arteriosclerotic changes was determined for the extra-cranial brain-supplying arteries, abdominal aorta, pelvis and leg arteries. In myocardial infarction patients coronary angiography was performed. Laboratory analyses included determination of C-reactive protein, fibrinogen, D-dimer, HDL-cholesterol, LDL-cholesterol and triglycerides.

RESULTS

The following ranking of C-reactive protein concentrations was found: controls < or = patients after myocardial infarction without atherosclerosis < or = patients with myocardial infarction and pre-clinical atherosclerosis < or = patients with myocardial infarction and clinically manifest atherosclerosis. Additionally, our data showed a significant association between C-reactive protein concentrations and the angiographically detected degree of coronary heart disease.

CONCLUSIONS

As C-reactive protein is a marker of inflammatory processes, our results in patients with clinically manifest and early pre-clinical atherosclerosis support the hypothesis that inflammatory processes in the vessel wall participate in atherogenesis. Moreover, they support the hypothesis of a causal relationship between an acute phase reaction and the pathogenesis of atherosclerosis in coronary arteries and other parts of the arterial vessel system.

[Knowledge about stroke among the German population]

BACKGROUND AND OBJECTIVE

Modern stroke therapy requires patients to correctly identify stroke symptoms and seek immediate hospital admission. US studies showed that only 57% of the population knew at least one stroke symptom. This is the first study about stroke knowledge among German populations.

METHODS

Using a cross-sectional questionnaire survey, 300 working-age participants of the PROCAM study, the Prospective Cardiovascular Münster Study, and 95 senior citizens of the Augsburg Study, a follow-up project of the MONICA survey 1989/90, were asked about stroke symptoms and what to do if they occur. Good knowledge about stroke was defined as knowing at least two stroke symptoms and calling the emergency medical system or seeking immediate hospital admission in case of symptoms.

RESULTS

Participation rate in the PROCAM study was 90%, while all senior citizens took part. The mean age of the working population was 41.2 years, the mean age of the retired population was 72.8 years. 35% of the working and 24.5% of the retired participants knew at least two stroke symptoms. Urgent hospital admission was selected by 78.2% of the occupational but only 41.5% of the retired participants. Good stroke knowledge was demonstrated by nearly a third of the workers but less than 10% of the elderly. Among the occupational population, being a white-collar worker or knowing someone with a stroke was a significant predictor of good stroke knowledge. Among senior citizens higher age and current smoking status were significant predictors.

CONCLUSION

Our study shows significant information deficits about stroke in our population: education needs to be geared especially towards the elderly.

Detection of missense mutations in the genes for lipoprotein lipase and hepatic triglyceride lipase in patients with dyslipidemia undergoing coronary angiography

Coronary events have a close association with a low HDL/hypertriglyceridemia (LHDL/HTG) phenotype. As enzymes that hydrolyze triglyceride-rich lipoproteins are associated with a modulation of both HDL cholesterol and triglycerides, we have tested the hypothesis that mutations in the genes encoding lipoprotein lipase (LPL) or hepatic lipase (HTGL) may contribute to the formation of coronary atherosclerosis and, thus, of coronary heart disease (CHD). The entire coding and boundary regions of LPL and HTGL genes were analyzed by direct sequencing in 20 patients with both LHDL/HTG and diagnosed CHD. In the LPL gene six different polymorphisms were identified with same frequencies observed in the general population. In the HTGL gene, besides several polymorphisms, we identified three missense mutations: Asn37His, Val73Met, and Ser267Phe. Population screening using allele specific PCR identified Val73Met as a polymorphism while the two others were absent from 100 control individuals. One of the mutations (Ser267Phe) is known to cause HTGL deficiency and is associated with type III hyperlipoproteinemia. Since this dyslipoproteinemia meets the criteria of LHDL/HTG, it is intriguing to speculate that missense mutations in HTGL may play a role in the pathogenesis of this atherogenic phenotype.

The effects of six months of treatment with a low-dose of conjugated oestrogens in menopausal women

OBJECTIVE

Hormone replacement therapy (HRT) is usually prescribed as medium- to high-dose formulations. Little is known, however, about dose-dependency of oestrogen effects on plasma hormone levels, markers of cardiovascular risk in lipid metabolism and the haemostatic system, or markers of bone turnover.

SUBJECTS AND DESIGN

In an open trial, three groups of 12 or 13 healthy, non-obese postmenopausal women received conjugated equine oestrogens (CEE) for 6 months at doses of 0.3 mg/day (group 1), 0.6 mg/day (group 2) or 1.25 mg/day (group 3). From day 1 to day 10, CEE was administered alone, and from day 11 to day 21, in combination with 5 mg of medrogestone. Each treatment cycle was followed by a pause of 7 days. Fasting blood samples were obtained before treatment as well as on days 10, 21 and 28 of the first, third and sixth months on treatment. All results obtained on day 10 were grouped together as phase A, on day 21 as phase B, and on day 28 as phase C.

MEASUREMENTS

Plasma concentrations of oestradiol (E), dehydroepiandrosterone sulphate (DHEA-S), total testosterone (T), FSH, PRL, sex hormone binding globulin (SHBG), type I procollagen propeptide (PICP) and the cross-linked carboxyterminal telopeptide of type I collagen (ICTP), total cholesterol, HDL-cholesterol, triglycerides (TG), apolipoprotein (apo) A-1, apo B, lipoprotein(a)[Lp (a)], fibrinogen, factor VIIc and plasminogen activator inhibitor 1 (PAI-1) were evaluated with commercially available kits.

RESULTS

Dose-dependently, the three regimens increased E, SHBG and factor VIIc activity and decreased FSH, DHEAS, cholesterol, LDL-cholesterol and apoB. HDL-cholesterol and apoA-1 were slightly decreased in group 1 but increased in groups 2 and 3. The high CEE dosage in group 3 resulted in a significant increase of TG and decrease of Lp(a) and PAI-1. Markers of bone turnover were not significantly changed by any CEE dosage.

CONCLUSIONS

Six months of treatment with 0.3 mg/day of conjugated equine oestrogen significantly lowers serum levels of total cholesterol and LDL-cholesterol without causing the adverse increases of triglycerides or factor VIIc, which were observed at higher doses. However, this low-dose treatment did not yield the maximal LDL-cholesterol lowering effect. Moreover, the positive effects of HRT on HDL-cholesterol, apolipoprotein A-I, lipoprotein (a) and plasminogen activator inhibitor-1 required at least the medium dose of 0.6 mg conjugated equine oestrogens per day. Therefore, further studies are needed to determine which dose of conjugated equine oestrogens has the optimal effect on cardiovascular risk and bone turnover.

Systemic inflammatory parameters in patients with atherosclerosis of the coronary and peripheral arteries

Plasma concentration of markers of inflammation are increased in patients with atherosclerosis. However, it is unclear whether the pattern and magnitude of this increase vary with the site and extent of disease. In 147 patients undergoing semiquantitative coronary angiography, we measured the acute-phase reactants C-reactive protein (CRP) or serum amyloid A (SAA); the proinflammatory cytokine interleukin 6 (IL-6); the active and total fractions of the anti-inflammatory cytokine transforming growth factor-beta (TGF-beta); the macrophage activation marker neopterin; and the infection marker procalcitonin. Compared with 62 patients without either coronary artery disease (CAD) or peripheral artery disease (PAD), 57 patients with CAD but no PAD showed greater median CRP (0. 4 versus 0.2 mg/dL, P=0.004) and IL-6 (3.8 versus 1.6 pg/mL, P=0. 007) levels and a lower level of active-TGF-beta (57 versus 100 ng/mL, P=0.038). Moreover, CRP, IL-6, and neopterin levels showed a positive and the active TGF-beta level a negative correlation with the extent of coronary atherosclerosis. Compared with these 57 patients with CAD alone, 15 patients with PAD and CAD had higher median levels of SAA (17 versus 7 mg/mL, P=0.008), IL-6 (12 versus 4 pg/mL, P=0.002), neopterin (14 versus 11 mg/dL, P=0.006), and total TGF-beta (11834 versus 6417 ng/L, P=0.001). However, these strong univariate associations of markers of inflammation and atherosclerosis were lost in multivariate analysis once age, sex, and high density lipoprotein cholesterol or fibrinogen were taken into account. Increased plasma levels of CRP, SAA, IL-6, TGF-beta, neopterin, and procalcitonin constitute an inflammatory signature of advanced atherosclerosis and are correlated with the extent of disease but do not provide discriminatory diagnostic power over and above established risk factors.

D-dimers in relation to the severity of arteriosclerosis in patients with stable angina pectoris after myocardial infarction

BACKGROUND

Plasma concentrations of D-dimers show the extent of intravascular fibrinolysis of cross-linked fibrin. Higher concentrations of D-dimers are found in the plasma of arteriosclerosis patients with increased fibrin metabolism. The present study was performed in order to investigate whether there is a relationship between the severity of arteriosclerosis and fibrinolytic activity indicated by plasma levels of D-dimer.

METHODS

The study populations consisted of 1112 men and 299 women with stable angina pectoris, on average 36+/-5.6 days after a myocardial infarction, as well as 326 men and 138 women with no clinical signs of cardiovascular disease. In addition to cardiological and angiological examinations, the lipid status and levels of fibrinogen, plasma viscosity, F 1+2, plasminogen, plasminogen activator inhibitor-1, D-dimer, and C-reactive protein of the participants were determined.

RESULTS

The plasma concentration of D-dimers increases with age, both in the group with coronary artery disease and in the control group, with the female gender showing consistently higher concentrations in both groups. D-dimers correlate with other parameters of the lipid and coagulation systems, which explains 32.0% and 39.2% of the variance in D-dimer values in men and women, respectively. A significant increase in the level of D-dimers can be found in participants with generalized arteriosclerosis, with a left ventricular ejection fraction </=40% as well as those with left-ventricular aneurysm.

CONCLUSION

This study indicates that there is increased fibrinolytic activity in patients with severe arteriosclerosis. This finding gives further support to the hypothesis that D-dimer concentration is dependent on the amount of fibrin associated with arteriosclerotic thrombi. However, because of the low specificity and wide overlap of D-dimer values between patients and controls, enhanced D-dimer values are of limited relevance above and beyond other lipid metabolism risk indicators for coronary artery disease or coronary artery disease and peripheral arterial occlusive disease.

Associations of obesity markers, insulin, and sex hormones with HDL-cholesterol levels in Turkish and German individuals

Turkish men and women have about 20% lower mean levels of HDL-C and apoA-I than German individuals. To obtain some information on the metabolic basis of this difference, we compared anthropometric data as well as serum levels of leptin, insulin, testosterone (T), estradiol (E2), and sex hormone binding globuline (SHBG) in 289 German and 120 Turkish men as well as in 108 German and 182 Turkish women aged 20-60. Individuals who smoke, take hormones, have overt diabetes mellitus, BMI > 30 kg/m2, triglycerides > 400 mg/dl, or LDL-cholesterol > 200 mg/dl were excluded. In both sexes, Turks had significantly lower levels of HDL-C, apoA-I, Lp(a), and SHBG than Germans. Moreover, German men had a larger waist circumference, lower levels of E2 and a lower ratio of T/SHBG. German women also had a lower BMI, smaller waist circumference, lower insulin levels and higher T levels. Mean values of age, waist-hip-ratio (WHR), leptin, triglycerides, LDL-C, and apoB did not differ significantly among Germans and Turks. Upon univariate analysis HDL-C had inverse correlations with BMI, waist circumference, WHR, leptin, and insulin as well as positive correlations with SHBG in both sexes. Upon multivariate analysis, most of the different levels of HDL-C and apoA-I between Germans and Turks were explained by ethnicity, independently of obesity markers, insulin, and sex hormones.

An ecological study of determinants of coronary heart disease rates: a comparison of Czech, Bavarian and Israeli men

BACKGROUND

The large differences in cardiovascular disease rates between Eastern and Western Europe have largely developed over the last few decades, and are only partly explained by classical risk factors. This study was set up to identify other potential determinants of these differences.

METHODS

This was an ecological study comparing random samples of men aged 45-64 years selected from three cities representing populations with different rates of cardiovascular mortality: Pardubice (Czech Republic), Augsburg (Bavaria, Germany), and Jerusalem (Israel). In total, 191 (response rate 70%), 153 (70%) and 162 (62%) men, respectively, participated. All centres followed the same study protocol. Lifestyle, anthropometry and biochemical risk factors were assessed by identical questionnaires, standardized medical examination, and central analyses of fasting blood samples.

RESULTS

The mortality rates in the study populations, as well as the prevalence of coronary heart disease in study samples, were highest in Czech, intermediate in Bavarian and low in Israeli men. This pattern was replicated across the three samples by mean blood pressure (P < 0.001), cigarette smoking (not significant), triglycerides (P < 0.05), fibrinogen or D-dimer levels (P < 0.05). On the other hand, the prevalence of diabetes and obesity were similar; total and high density lipoprotein (HDL)-cholesterol, apolipoprotein B, lipoprotein (Lp(a)) and glucose did not differ between Czech and Bavarian men; and Czechs had particularly low levels of serum insulin and factor VIIc. Israelis had low fasting glucose and total cholesterol, as well as HDL-cholesterol levels and a high Lp(a) (each P < 0.001) compared with the two other samples. Striking differences were found for plasma homocysteine (10.5 in Czechs versus 8.9 mumol/l in Bavarians, P < 0.001) and for alpha-carotene (geometric mean in Czechs 16, Bavarians 21 and Israelis 30 micrograms/l), beta-carotene (60, 110 and 102 micrograms/l), and lycopene (84, 177 and 223 micrograms/l), respectively; all P-values < 0.001). Adjustment for obesity or smoking did not change these estimates. There were no differences in the levels of tocopherol and retinol.

CONCLUSIONS

Czech men had high levels of blood pressure, triglycerides, fibrinogen and D-dimer but many other traditional risk factors, as well as indicators of metabolic disorders and vitamins A and E, did not differ between the study samples. The low levels of carotenoids and high concentrations of homocysteine in Czech men seem to reflect their low dietary intakes of fruit and vegetables. The results provide indirect support for the importance of dietary factors in the East-West morbidity and mortality divide.

Obesity, mortality and cardiovascular disease in the Münster Heart Study (PROCAM)

In the Münster Heart Study (PROCAM), 16,288 men aged 40.6 +/- 11.3 years (mean +/- S.D.) and 7328 women aged 36.0 +/- 12.3 years were enrolled between 1979 and 1991. Mean body mass indices (BMIs) were 25.6 +/- 3.3 and 23.8 +/- 4.1 kg/m2 in men and women, respectively. There was a graded and continuous positive interaction in both men and women between BMI, age and serum total cholesterol, low density lipoprotein (LDL) cholesterol, and blood pressure (both systolic and diastolic). High density lipoprotein (HDL) cholesterol tended to increase with age, but decreased in graded fashion with increases in BMI in both sexes. Triglyceride increased with BMI in both sexes and with age in women, but decreased in the older age groups of overweight and obese men. Though fasting blood glucose increased with age and BMI in both sexes, the increase was more marked in women. Among the 10,856 men aged 36-65 years at study entry, 313 deaths occurred within a follow-up period of 7.1 +/- 2.4 years. Among these men, increased mortality was seen at high BMIs in both smokers and non-smokers and was caused by coronary heart disease (CHD). Increased mortality at low BMI was seen in smokers but not in non-smokers and was due to an increase in cancer deaths. The BMI-associated increase in CHD death was completely accounted for by the factors contained in the Münster Heart Study (PROCAM) risk algorithm, indicating that the effect of overweight and obesity on CHD is mediated via other risk factors.

Effect of sympathetic activity on capsaicin-evoked pain, hyperalgesia, and vasodilatation

BACKGROUND

Painful nerve and tissue injuries can be exacerbated by activity in sympathetic neurons. The mechanisms of sympathetically maintained pain (SMP) are unclear.

OBJECTIVE

To determine the effect of cutaneous sympathetic activity on pain induced by primary afferent C-nociceptor sensitization with capsaicin in humans.

METHODS

In healthy volunteers capsaicin was applied topically (n = 12) or injected into the forearm skin (n = 10) to induce spontaneous pain, dynamic and punctate mechanical hyperalgesia, and antidromic (axon reflex) vasodilatation (flare). Intensity of pain and hyperalgesia, axon reflex vasodilatation (laser Doppler), and flare size and area of hyperalgesia (planimetry) were assessed. The local skin temperature at the application and measurement sites was kept constant at 35 degrees C. In each individual the analyses were performed during the presence of high and low sympathetic skin activity induced by whole-body cooling and warming with a thermal suit. By this method sympathetic vasoconstrictor activity is modulated in the widest range that can be achieved physiologically. The degree of vasoconstrictor discharge was monitored by measuring skin blood flow (laser Doppler) and temperature (infrared thermometry) at the index finger.

RESULTS

The intensity and spatial distribution of capsaicin-evoked spontaneous pain and dynamic and punctate mechanical hyperalgesia were identical during the presence of high and low sympathetic discharge. Antidromic vasodilatation and flare size were significantly diminished when sympathetic vasoconstrictor neurons were excited.

CONCLUSIONS

Cutaneous sympathetic vasoconstrictor activity does not influence spontaneous pain and mechanical hyperalgesia after capsaicin-induced C-nociceptor sensitization. When using physiologic stimulation of sympathetic activity, the capsaicin model is not useful for elucidating mechanisms of SMP. In neuropathic pain states with SMP, different mechanisms may be present.

Genetic and biochemical screening for endocrine disease

The development of biochemical and genetic screening tests for inherited endocrine diseases has dramatically changed our approach to surgical patients with endocrine tumors. Among more than 1800 patients with endocrine tumors and a possible inherited disease operated on between 1986 and 1997, there were 6.1% to 7.3% who were found to have a familial disease associated with familial medullary thyroid cancer, (MTC), multiple endocrine neoplasia type IIa (MEN-IIa), MEN-IIb, or MEN-I. Genetic testing for the RET proto-oncogene is therefore recommended for all patients with MTC, and testing for the MEN-I gene is recommended in patients with suspected MEN-I and in specific clinical subgroups with an increased probability of endocrine tumor heredity. Early treatment based on early diagnosis by genetic testing appears to improve survival and to decrease morbidity in these patients.

Smoking, lipoproteins and coronary heart disease risk. Data from the Münster Heart Study (PROCAM)

AIMS

The mechanism of the increase in coronary heart disease risk associated with smoking is unclear, but may partly be due to smoking-related changes in intermediate risk factors such as lipid levels, fibrinogen and blood pressure. We therefore examined the distribution of these variables among smokers and non-smokers in the Münster Heart Study.

METHODS

20696 men, aged 41.7+/-2.7 years (mean +/- SD) and 10212 women, aged 37.0+/-2.6 years, were enrolled between 1978 and 1995. Thirty-two percent of women and 36% of men smoked. Compared to non-smokers, mean levels of low density lipoprotein cholesterol, total cholesterol, triglycerides and fibrinogen were increased, respectively, by 1.4%, 0.9%, 15% and 12.1% in male and by 2.0%, 5.5%, 12% and 3.4% in female smokers. Mean high density lipoprotein cholesterol levels, body mass index and blood pressure were reduced, respectively, by 6.4%, 3.8%, and 2% in male, and by 6.7% 1.2% and 2% in female smokers. In the subgroup of 4639 men aged 40 to 65 with 8 years of follow-up, the coronary event rate (definite myocardial infarction, sudden cardiac death) in cigarette smokers was more than twice that of non-smokers with otherwise identical risk factors.

CONCLUSION

In the Münster Heart Study, smoking was associated with adverse changes in lipids (of greater magnitude in women), and fibrinogen (of greater magnitude in men). However, these changes explained only a small part of the smoking-related increase in coronary heart disease risk.

Plasminogen activator inhibitor-1 4G/5G-polymorphism and factor V Q506 mutation are not associated with myocardial infarction in young men

Several recent studies have reported contradicting results concerning the relevance of the plasminogen activator inhibitor-1 (PAI-1) 4G/5G-polymorphism for myocardial infarction. In addition, the common factor V Q506 (FV:Q506) mutation is frequently discussed as a risk factor for arterial thrombosis, but evidence is rare. In order to further highlight the role of both polymorphisms in myocardial infarction, we investigated 241 young male myocardial infarction patients (< or = 45 years-of-age) aged 38.6+/-4.4 years (mean+/-SD) for the presence of both genotypes. The control group consisted of 179 healthy men aged 47.1+/-6.4 years (mean+/-SD) of the same ethnic background as the patients. Neither the distribution of the PAI-1 4G/5G-polymorphism nor the prevalence of the FV: Q506 mutation was significantly different between young patients and controls (4G/4G-genotype: chi2=2.08, NS; odds ratio 1.36, 95% confidence interval 0.89-2.06; FV:Q506 mutation: chi2=0.33, NS; odds ratio 1.33, 95% confidence interval 0.64-2.78). Moreover, the PAI-1 4G/5G-distribution did not differ significantly between patients and controls in subgroups by tertiles of triglyceride levels. In conclusion, in the present study neither homozygosity for the 4G allele of the PAI-1 4G/5G-polymorphism nor the FV:Q506 mutation led to an increased risk of myocardial infarction in young men.

The emergence of triglycerides as a significant independent risk factor in coronary artery disease

The Prospective Cardiovascular Münster (PROCAM) study involved 4849 middle-aged men who were followed up for 8 years to record the incidence of coronary heart disease (CHD) events according to the risk factors present at study entry. The study showed that fasting levels of triglycerides were an independent risk factor for CHD events, irrespective of serum levels of high density lipoprotein cholesterol (HDL-C) or low density lipoprotein cholesterol (LDL-C). Other independent predictors of CHD included serum levels of LDL-C and HDL-C, age, systolic blood pressure, cigarette smoking, diabetes mellitus, a family history of myocardial infarction and angina pectoris, but did not include total serum cholesterol levels. Individuals with an LDL-C/HDL-C ratio > 5 had a 19.2% chance of experiencing a CHD event in the next 8 years. Furthermore, if an LDL-C/HDL-C ratio > 5 was combined with hypertriglyceridaemia (> or = 2.3 mmol. l-1), the risk of CHD increased to 26.9%. The association between hypertriglyceridaemia and CHD events may be related to the presence of atherogenic, triglyceride-rich particles in plasma, such as LDL and very low density lipoproteins. High triglyceride levels may also predispose to thrombosis. Individuals with potentially atherogenic lipid profiles should be managed initially through the introduction of lifestyle changes. However, if these fail to achieve recommended target values, lipid-lowering therapy should be considered.