[SF-36 Health Survey in Rehabilitation Research. Findings from the North German Network for Rehabilitation Research, NVRF, within the rehabilitation research funding program]

The SF-36 Health Survey and its 12-item abridged form is an instrument for the assessment of health related quality of life that can be used with healthy persons and patient populations. Its use has been recommended within a large German multicentre rehabilitation research programme. The paper examines missing data across all five study projects of the North German Network for Rehabilitation Research (NVRF) as well as psychometric properties of the instrument. In addition, data were compared to representative norm data using the SF-36 (SF-12) in the German National Health Survey. Results showed that there were few missing data in the SF-36. Examining the impact of age, gender and health status yielded effects of higher age and female gender on missing data. Psychometric analyses showed good to excellent results of the instrument in terms of scale fit and reliability. In terms of convergent validity, medium to high correlation of the SF-36 subscales with comparable instruments (e. g. SCL-90-R) could be found. Summarizing, the SF-36/SF-12 can be recommended for use in rehabilitation research. Analyses regarding sensitivity should be conducted in future studies.

Diagnosis of glaucoma by indirect classifiers

OBJECTIVES

Demonstration of the applicability of a framework called indirect classification to the example of glaucoma classification. Indirect classification combines medical a priori knowledge and statistical classification methods. The method is compared to direct classification approaches with respect to the estimated misclassification error.

METHODS

Indirect classification is applied using classification trees and the diagnosis of glaucoma. Misclassification errors are reduced by bootstrap aggregation. As direct classification methods linear discriminant analysis, classification trees and bootstrap aggregated classification trees are utilized in the problem of glaucoma diagnosis. Misclassification rates are estimated via 10-fold cross-validation.

RESULTS

Indirect classification techniques reduce the misclassification error in the context of glaucoma classification compared to direct classification methods.

CONCLUSIONS

Embedding a priori knowledge into statistical classification techniques can improve misclassification results. Indirect classification offers a framework to realize this combination.

Effects of fine and ultrafine particles on cardiorespiratory symptoms in elderly subjects with coronary heart disease: the ULTRA study

The ULTRA Study, a study investigating the association between fine and ultrafine particulate air pollution and cardiorespiratory health, was conducted during the winter of 1998-1999 in Amsterdam, the Netherlands; Erfurt, Germany; and Helsinki, Finland. At each study center, a panel of elderly subjects with coronary heart disease recorded cardiac and respiratory symptoms in a diary. Exposure to ambient air pollution was characterized by measuring daily mass concentrations of particles smaller than 10 micro m (PM(10)) and 2.5 micro m (PM(2.5)), number concentrations of ultrafine particles (NC(0.01-0.1)), and gases. Odds ratios for the relation of symptoms to air pollution, adjusted for time trend, respiratory infections, and meteorologic variables, were mostly homogeneous across the centers. No association was found between air pollution and chest pain. A 10- micro g/m(3) increase in PM(2.5) was positively associated with the incidence of shortness of breath (odds ratio (OR) = 1.12, 95% confidence interval (CI): 1.02, 1.24) and with avoidance of activities (OR = 1.09, 95% CI: 0.97, 1.22). NC(0.01-0.1) was only associated with the prevalence of avoidance of activities (OR = 1.10, 95% CI: 1.01, 1.19). In conclusion, PM(2.5) was associated with some cardiac symptoms in three panels of elderly subjects. PM(2.5 )was more strongly related to cardiorespiratory symptoms than ultrafine particles were.

Surgical management of thoracic outlet syndrome

Background

The role of surgical decompression for thoracic outlet syndrome (TOS) is not clearly established, especially for the neurological (N-TOS) or venous (V-TOS) variants. Reports lack objective diagnostic criteria and follow-up. American series almost exclusively describe N-TOS. In the authors' practice, arterial TOS (A-TOS) is much more common. Patients are treated by a multidisciplinary team and surgery is reserved for those failing to respond to conservative measures.

Methods

Data regarding assessment, diagnosis (clinical, radiology, electromyography, duplex) are collected prospectively on a database (Paradox). Independent follow-up has categorized surgical results by structured questionnaire.

Results

Of 129 patients (104 women; median age 37 years), 91 underwent transaxillary first rib resection (50 A-TOS, 31 N-TOS, ten V-TOS), 24 had a supraclavicular scalenectomy (rib resection; all N-TOS) and 14 had a combined procedure (five A-TOS, nine N-TOS). Eleven were reoperations. Early results (6 months) were available for 122 patients.

Overall 91 per cent of patients with A-TOS rated the outcome as excellent/good, compared with 72 per cent of those with N-TOS and nine of ten with V-TOS. Life-table analysis confirmed a durable outcome at up to 6 years. Of 30 patients with A-TOS for whom data were complete, postoperative duplex imaging was normal in 28.

Conclusion

Careful patient selection following a concerted effort at conservative management yields good results. These data are useful for counselling patients who may be facing surgery for this disabling condition.

Pretreatment serum levels of matrix metalloproteinase-9 and vascular endothelial growth factor in non-small-cell lung cancer

BACKGROUND

Matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF) are two proteins involved in angiogenesis. In the present study we investigated the association of pretreatment MMP-9 and VEGF serum levels with clinicopathological parameters and outcome in patients with non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

From February 1998 to October 1999, pretreatment serum levels of MMP-9 and VEGF were analysed in 118 patients with enzyme-linked immunoassays. At diagnosis 50 patients (42%) were staged as early disease (I/II), 27 patients (23%) as locally advanced (IIIA/IIIB), and 41 patients (35%) had metastatic disease (IV). In 72 of the 118 patients tumours were resected and 46 patients received combination chemotherapy with gemcitabine and vinorelbine.

RESULTS

The median survival of all 118 patients was 602 days. The 72 patients who had undergone surgery had a median survival of 972 days and the 46 patients who were treated with chemotherapy had a median survival of 298 days (P <0.001). Resected patients with stage I/II disease and an MMP-9 serum level <or=1293 ng/ml or a VEGF serum level <or=630 pg/ml had a significantly longer survival (median survival longer than 1218 days) than patients with higher serum levels (median survival 421 days) (P = 0.001 for MMP-9; P = 0.04 for VEGF). No significant difference in survival was observed in patients with resected stage III disease. Besides tumour stage, Karnofsky performance status and gender, the pretreatment serum level of MMP-9 was identified as an independent prognostic factor in a multivariate Cox regression analysis.

CONCLUSIONS

Future studies may support our hypothesis that the pretreatment serum level of MMP-9 is a new powerful prognostic marker and can help to stratify NSCLC patients with stage I/II disease into low- and high-risk groups.

Increased asthma medication use in association with ambient fine and ultrafine particles

The association between particulate air pollution and asthma medication use and symptoms was assessed in a panel study of 53 adult asthmatics in Erfurt, Germany in winter 1996/1997. Number concentrations of ultrafine particles, 0.01-0.1 microm in diameter (NC(0.01-0.1), mean 17,300 x cm(-3), and mass concentrations of fine particles 0.01-2.5 microm in diameter (MC(0.01-2.5)), mean 30.3 microg x m(-3), were measured concurrently. They were not highly correlated (r=0.45). The associations between ambient particle concentrations and the prevalence of inhaled beta2-agonist, corticosteroid use and asthma symptoms, were analysed separately with logistic regression models, adjusting for trend, temperature, weekend, holidays, and first order autocorrelation of the error. Cumulative exposures over 14 days of ultrafine and fine particles were associated with corticosteroid use. Beta2-agonist use was associated with 5-day mean NC(0.01-0.1) and MC(0.01-2.5). The prevalence of asthma symptoms was associated with ambient particle concentrations. The results suggest that reported asthma medication use and symptoms increase in association with particulate air pollution and gaseous pollutants such as nitrogen dioxide.

[Rehabilitation score for patients with type 2 Diabetes mellitus: An instrument to standardize assessment of the need for rehabilitation]

Type 2 diabetes is considered a multidimensional health impairment which includes several components like risk factors, cofactors and complications. The early and consequent therapy of all of these components reduces secondary complications. Instead of simply applying drug treatment, a more holistic concept including behavioural medicine therapy and empowerment of patients has been found much more effective. The facilities required for such a multifactorial therapy by different health care professions could easily be provided by the medical rehabilitation services available under the German pension insurance scheme. However, this emphasizes the demand for standardized protocols to achieve an objective allocation of rehabilitation services to individuals in need. In an epidemiological study on 12 429 working insurants (age 41 - 60 years) of the pension insurance fund in the region of Luebeck, persons suffering from type 2 diabetes were identified and evaluated regarding a need for medical rehabilitation. Therefore, an algorithm was developed quantifying the multidimensional disturbances which accumulate in type 2 diabetes mellitus. The following indicators are taken into consideration: risk factors like eating behaviour, lack of physical activity, smoking and stress; metabolic parameters such as HbA1c and plasma lipids; cofactors like hypertension and depression and, additionally, the acute complication of hypoglycaemia. Based on this rehabilitation score, 19 % of cases in a preliminary evaluation of 79 patients with type 2 diabetes showed a need for medical rehabilitation therapy.

The neuroendocrine control of glucose allocation

Here we propose that glucose metabolism can be understood on the basis of three concept-derived axioms: (I) A hierarchy exists among the glucose-utilizing organs with the brain served first, followed by muscle and fat. (II) Tissue-specific glucose transporters allocate glucose among organs in order to maintain brain glucose concentrations. (III) Exogenous carbohydrate supply compensates for glucose alterations that can temporarily occur in muscle and fat. Derived from the control theory, the simplest solution of allocating supply to 2 organs, e.g. brain and muscle, is a "fishbone"-structured model. We reviewed the literature, searching for neuroendocrine and metabolic mechanisms that can fulfill control functions in such a model: The tissue-specific glucose transporters are differentially regulated. GLUT 1, carrying glucose across the blood-brain-barrier, is independent of insulin. Instead, this trans-endothelial glucose transporter is rather dependent on potent regulators of blood vessel function like vascular endothelial growth factor - a pituitary counterregulatory hormone. GLUT 4, carrying glucose across the membranes of muscle and fat cells, depends on insulin. Thereby, insulin allocates glucose to muscle and fat. The hypothalamus-pituitary-adrenal (HPA) axis, the sympathetic nervous system (SNS), and vascular endothelial growth factor allocate glucose to the brain. Multiple "sensors" (some of which have only recently been identified as ATP sensitive potassium channels) measure glucose or glucose equivalents at various sites of the body: the ventromedial hypothalamus, the lateral hypothalamus, portal vein, pancreatic beta cell, renal tubule, muscle and adipose tissue. Feedback pathways both from the brain and from muscle and fat are involved in regulating glucose allocation and exogenous glucose supply. The main feedback signal from the brain is found to be glucose, that from muscle and fat appears to be leptin. In fact, the literature search revealed two or more biological mechanisms for the function of each component in the model, finding glucose regulation highly redundant. This review focuses on "brain glucose" control. The concept of glucose allocation presented here challenges the common opinion of "blood glucose" being the main parameter controlled. According to the latter opinion, hyperglycemia in the metabolic syndrome is due to a putative defect located within the closed loop including the beta cell, muscle and fat cells. That traditional view leaves some peculiarities of e.g. the metabolic syndrome unexplained. The concept of glucose allocation, however, would predict that weight gain - with abundance of glucose in muscle and fat - increases feedback to the brain (via hyperleptinemia) which in turn results in HPA-axis and SNS overdrive, impaired insulin secretion, and insulin resistance. HPA-axis overdrive would account for metabolic abnormalities such as central adiposity, hyperglycemia, dyslipidemia, and hypertension, that are well known clinical aspects the metabolic syndrome. This novel viewpoint of "brain glucose" control may shed new light on the pathogenesis of the metabolic syndrome and type 2 diabetes.

The effect of experimentally induced insulin resistance on the leptin response to hyperinsulinaemia

OBJECTIVE

Insulin is thought to be an important regulator of leptin secretion. However, increasing evidence suggests that insulin-mediated glucose uptake rather than insulin per se regulates circulating leptin concentration. Here, we hypothesised that a reduction of insulin sensitivity, ie insulin resistance, will diminish the stimulatory effect of insulin on leptin secretion as a consequence of decreased insulin-mediated glucose uptake.

DESIGN

Changes in serum leptin concentration during 30 hyperinsulinaemic-hypoglycaemic clamps were studied after induction of different levels of insulin resistance in normal-weight men. In 15 subjects insulin sensitivity was reduced by exposing them to a 2.5 h antecedent hypoglycaemia (3.1 mmol/l) induced by a high rate of insulin infusion (15.0 mU/min/kg) on the day before the proper experiment ('ante-hypo' condition). In the other 15 subjects no antecedent hypoglycaemia was induced ('control' condition). The proper experiment on both conditions was a 6 h stepwise hypoglycaemic clamp induced by a constant rate of insulin infusion (1.5 mU/min/kg).

SUBJECTS

Experiments were carried out in 30 lean healthy subjects (age, mean +/- s.e.m., 26 +/- 1 y; body mass index, 23.1 +/- 0.6 kg/m2).

RESULTS

As expected, glucose demand during the clamp was lower in the ante-hypo condition than in the control condition (gram of glucose infused per kilogram body weight, 1.52 +/- 0.16 vs 2.01 +/- 0.17 g/kg; P < 0.05). During the clamp, leptin levels increased by 25.4 +/- 4.3% in the control condition (P < 0.05), but not in the ante-hypo condition (+4.8 +/- 4.5%; P > 0.25). Thus, serum leptin response to the clamp significantly differed between the two conditions (P < 0.01). Across both conditions, the increase of leptin levels during the clamp was correlated with the amount of glucose infused (r = 0.37; P < 0.05).

CONCLUSION

Considering that insulin concentrations were identical during both clamp conditions, the data indicate that experimentally-induced insulin resistance diminishes the stimulatory effect of insulin on leptin secretion.

Tests of relativity using a cryogenic optical resonator

A 190-day comparison of the optical frequencies defined by an optical cavity and a molecular electronic transition is analyzed for the velocity independence of the speed of light (Kennedy-Thorndike test) and the universality of the gravitational redshift. The modulation of the laboratory velocity and the gravitational potential were provided by Earth's orbital motion around the Sun. We find a velocity-dependence coefficient of (1.9+/-2.1)x10(-5), 3 times lower compared to the best previous test. Alternatively, the data confirm the gravitational redshift for an electronic transition at the 4% level. Prospects for significant improvements of the tests are discussed.

Hysteroscopic endometrial destruction, optimum method for preoperative endometrial preparation: a prospective, randomized, multicenter evaluation

OBJECTIVE

To compare the outcome and cost-effectiveness of various forms of preoperative endometrial preparation prior to hysteroscopic endometrial destruction for abnormal uterine bleeding.

METHODS

This was a multicenter, prospective, comparative, randomized study conducted in a tertiary care hospital in Cairo, Egypt and 2 academic tertiary care teaching hospitals in the United States. One hundred thirty-one premenopausal women, who had completed childbearing, mean age of 45.7 years, with abnormal uterine bleeding refractory to medical management without histologic evidence of endometrial neoplasia were studied. The 131 patients were randomized for preoperative preparation for hysteroscopic endometrial destruction into 1 of 5 groups as follows: Group I, dilation and curettage (D & C) (39); Group II, gonadotropin-releasing hormone analogue (GnRHa) for 1 month (23); Group III, GnRHa for 3 months (26); Group IV, danazol for 3 months (26); and Group V, medroxyprogesterone acetate (MPA) 15 mg for 3 months (27). The choice of endometrial ablation or endometrial resection was left to the surgeon.

RESULTS

Improvement in bleeding patterns, amenorrhea, operative times, complications, and relative cost were the measured outcomes. The mean follow-up time was 1 year from the time of the procedure. Overall, in Group I, 39/39 (100%) improved and 7/39 (18.0%) experienced amenorrhea; in Group II, 21/23 (91.3%) improved and 9/23 (39.1%) experienced amenorrhea; in Group III, 24/26 (92.3%) improved and 10/26 (38.5%) experienced amenorrhea; in Group IV, 24/26 (92.3%) improved and 9/26 (34.6%) experienced amenorrhea; and in Group V, 23/27 (85.1%) improved and 7/27 (25.9%) experienced amenorrhea.

CONCLUSION

Endometrial destruction whether by the ablation or resection technique, regardless of the type of surgical pretreatment is a safe and effective surgical approach for treating abnormal uterine bleeding. D & C or MPA appear to be the most cost-effective pretreatment regimens. MPA pretreatment may confer the added advantage of decreasing blood flow and allowing better hysteroscopic visualization than D & C pretreatment.

[Recurrent hypoglycemia caused by malignant insulinoma: chemoembolization as a therapeutic option]

HISTORY AND CLINICAL FINDINGS

A 73-year-old previously healthy woman presented with recurrent weakness, vertigo and perioral paresthesia of 3 months' duration. Physical examination on admission was unremarkable and revealed a patient in good condition.

INVESTIGATIONS

Recurrent episodes of fasting hypoglycemia let us to proceed with a fasting test. The test was stopped after 24 hours when the patient became presyncopal and was found to have a blood sugar value of 2.2 mmol/l (accompanied by inadequately increased values for proinsulin, insulin and C-peptide). Ultrasound and computertomography of the abdomen showed a huge inhomogeneous mass in the tail of pancreas and multiple lesions in the liver, respectively. Core needle biopsies revealed typical histopathological findings of a neuroendocrine carcinoma.

TREATMENT AND COURSE

Eight cycles of chemotherapy were given using streptozotocin/doxorubicin for three cycles and streptozotocin/5-fluorouracil for the remaining therapy over a period of 16 months resulting in a reduction in size of liver metastases and improvement of symptoms. Following 6 months without any therapy new episodes of severe hypoglycemia and progression of the liver metastases occurred. Despite seven further cycles of chemotherapy and additional treatment with diazoxide/octreotide the patient remained hypoglycemic and continuous glucose infusions became necessary. Therefore, chemoembolization of the liver with streptozotocin/5-fluorouracil and lipiodol-emulsion was performed. This resulted in a significant improvement of symptoms and the patient could subsequently be discharged. The patient died 4 months later.

CONCLUSION

Chemoembolization is an effective possibility in the palliative treatment of advanced malignant insulinoma.

Hypoglycemia, but not insulin, acutely decreases LH and T secretion in men

Hypoandrogenemia is frequently associated with hyperinsulinemia in men with the metabolic syndrome. We questioned whether insulin or changes in blood glucose levels influence pituitary gonadotropin secretion or testicular steroidogenesis in healthy men. Also, the relationship between hypoglycemia-induced activation of the hypothalamus-pituitary-adrenal axis and altered steroidogenesis was examined. Euglycemic and hypoglycemic clamp experiments were performed in 30 healthy men over a period of 6 h. Half of the men were infused with insulin at a rate of 1.5 mU/min.kg; the other half were infused at a rate of 15.0 mU/min.kg. Plasma glucose was held constant during a euglycemic clamp session and was decreased stepwise in a hypoglycemic clamp session. LH and total/free T concentrations decreased under hypoglycemic conditions regardless of the rate of insulin infusion. With euglycemic conditions, LH and T levels remained unchanged. Dehydroepiandrosterone concentrations increased during hypoglycemia, but not during the euglycemic conditions. The FSH concentration was not affected by insulin or glycemic clamps. Hypoglycemia acutely suppresses T secretion, and this effect is apparently mediated by pituitary LH. Insulin is ineffective. As counterregulation to hypoglycemia begins at normoglycemic ranges in poorly controlled type 2 diabetes and probably also in patients with long-term perturbed glucose regulation in the metabolic syndrome, control of glucose-responsive neurons in the brain may contribute to hypoandrogenemia. Apart from down-regulation of hypothalamic release of GnRH, concurrent activation of the pituitary-adrenal axis (i.e. increased release of dehydroepiandrosterone) may add to the suppressive effect of hypoglycemia on gonadal steroidogenesis.

Improving influence of insulin on cognitive functions in humans

Insulin receptors have been identified in limbic brain structures, but their functional relevance is still unclear. In order to characterize some of their effects, we evaluated auditory evoked brain potentials (AEP) in a vigilance task, behavioral measures of memory (recall of words) and selective attention (Stroop test) during infusion of insulin. The hormone was infused at two different rates (1.5 mU/kg x min, "low insulin", and 15 mU/kg x min, "high insulin"), inducing respectively serum levels of 543 +/- 34 and 24,029 +/- 1,595 pmol/l. This experimental design allowed to compare cognitive parameters under two conditions presenting markedly different insulin levels, but with minimal incidence on blood glucose concentrations since these were kept constant by glucose infusion. A "no insulin treatment" group was not included in order to avoid leaving patients infused with glucose without insulin treatment. Measures were taken during a baseline phase preceding insulin infusion and every 90 min during the 360 min of insulin infusion. Compared with "low insulin", "high insulin" induced a slow negative potential shift in the AEP over the frontal cortex (average amplitude, high insulin: 0.27 +/- 0.48 microV; low insulin: 1.87 +/- 0.48 microV, p < 0.005), which was paralleled by enhanced memory performance (words recalled, high insulin: 22.04 +/- 0.93; low insulin: 19.29 +/- 0.92, p < 0.05). Also, during "high insulin" subjects displayed enhanced performance on the Stroop test (p < 0.05) and expressed less difficulty in thinking than during "low insulin" (p < 0.03). Results indicate an improving effect of insulin on cognitive function, and may provide a frame for further investigations of neurobehavioral effects of insulin in patients with lowered or enhanced brain insulin, i.e., patients with Alzheimer's disease or diabetes mellitus.

Losartan attenuates symptomatic and hormonal responses to hypoglycemia in humans

OBJECTIVE

Reduced awareness of hypoglycemic symptoms and compromised hormonal counterregulation increase the risk of severe hypoglycemia in people with diabetes mellitus. Up to the present, angiotensin 1 receptor blockers, which play an important role in controlling diabetic complications, have not been known to increase the risk of hypoglycemia. Nevertheless, we observed 3 cases of diabetic patients complaining of reduced awareness of hypoglycemic symptoms while they were under treatment with losartan in our outpatients clinic. We therefore investigated the effects of losartan on symptomatic and hormonal responses to hypoglycemia in humans.

RESEARCH DESIGN AND METHODS

We carried out a randomized, double-blind, crossover study including 16 healthy men. The subjects received losartan 50 mg/d versus placebo. Treatment periods lasted for 7 days and were followed by a stepwise hypoglycemic clamp session (4.5 to 3.8 to 3.1 to 2.4 mmol/L) with measurement of counterregulatory hormones (epinephrine, norepinephrine, adrenocorticotropin, cortisol, glucagon), symptoms, and hemodynamic parameters (blood pressure, heart rate).

RESULTS

Losartan attenuated the hypoglycemia-induced rise in plasma epinephrine (6480 +/- 490 pmol/L versus placebo 8970 +/- 790 pmol/L; P <.001) and the rise in plasma adrenocorticotropin (21 +/- 2 pmol/L versus 26 +/- 3 pmol/L; P <.01). Losartan also reduced symptom scores during hypoglycemia (P <.05).

CONCLUSION

We conclude that short-term treatment with losartan slightly attenuates symptomatic and hormonal responses to hypoglycemia. At present, for patients who are unaware of hypoglycemia and who require antihypertensive or nephroprotective treatment, we would recommend caution concerning treatment with losartan.

High-resolution Doppler-free molecular spectroscopy with a continuous-wave optical parametric oscillator

We present a reliable, narrow-linewidth (100-kHz) continous-wave optical parametric oscillator (OPO) suitable for high-resolution spectroscopy applications. The singly resonant OPO with a resonated pump is based on periodically poled lithium niobate crystal and features a specially designed intracavity etalon, which permits precise tuning to any desired wavelength in a wide range. We demonstrate Doppler-free spectroscopy of a rovibrational transition of methane at 3.39 mum.

Metformin does not adversely affect hormonal and symptomatic responses to recurrent hypoglycemia

Body weight gain and severe hypoglycemia are the major adverse effects of insulin therapy in type 2 diabetic patients. Metformin has been shown to prevent insulin therapy-induced body weight gain when used in combination with insulin. However, the effects of metformin on hormonal and symptomatic responses to hypoglycemia mediating hypoglycemia awareness have not been assessed to date. Fifteen young healthy men were treated with 850 mg metformin and placebo twice daily for a 16-d period in a double blind, cross-over design. On the last 2 d of the treatment period, the subjects underwent three hypoglycemic clamp experiments, with the first and the last performed with identical patterns of plasma glucose decrease. Differences between the effects of metformin and placebo (effect of metformin) as well as between first and last hypoglycemic clamps (effect of antecedent hypoglycemia) were assessed. Antecedent hypoglycemia significantly reduced epinephrine, ACTH, cortisol, glucagon, GH, and symptomatic responses to hypoglycemia (P < 0.05 for all variables). There was no detectable effect of metformin on epinephrine, norepinephrine, ACTH, cortisol, glucagon, or autonomic symptomatic response to hypoglycemia (P > 0.05 for all comparisons), except that metformin slightly increased the response of GH to hypoglycemia (P = 0.039). The latter finding may be due to an IGF-I-reducing effect of metformin, as after 14 d of metformin treatment baseline levels of IGF-I were significantly lower than in the placebo condition (236.9 +/- 13.9 vs. 263.2 +/- 14.4 microg/liter; P = 0.015). The data indicate that metformin does not adversely affect hormonal and symptomatic responses to hypoglycemia. This finding appears to be relevant with regard to the safety of the combination of metformin with insulin therapy.

Particulate air pollution is associated with an acute phase response in men; results from the MONICA-Augsburg Study

AIMS

Episodes of increased air pollution are associated with increases in hospital admissions for cardiovascular disease. Even modest acute phase responses are associated with increased risk of coronary heart disease. The study investigates whether induction of an acute phase response by exposure to air pollution may contribute to cardiovascular pathology.

METHODS AND RESULTS

A prospective cohort study based on a survey in 1984/85 with a 3-year follow-up was conducted in 631 randomly selected men aged 45 to 64 years free of cardiovascular disease at entry 1984/85. Serum C-reactive protein concentrations were determined by a high sensitivity immunoradiometric assay. C-reactive protein concentration was increased in association with the 1985 air pollution episode. In multivariate analyses, elevated concentrations were independently associated with concentrations of total suspended particles and the sulphur dioxide episode. At ambient concentrations of pollution, as noted during the 1985 air pollution episode, the odds of observing C-reactive protein concentrations above 5.7 mg. l(-1)(>90th percentile) tripled, and increases of 26 microg. m(-3)total suspended particles (mean of 5 days) raised the odds of C-reactive protein levels 50% above the 90th percentile.

CONCLUSIONS

Exposure to current levels of particulate matter in the atmosphere elicits an acute phase response in randomly selected healthy middle-aged men, which may contribute to the increased cardiovascular risk caused by air pollution.