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Biomedical subjects

Klaus Mann

Publications and source records attributed to Klaus Mann.

At least 19 recordsLinked to original sources
PubMed2007

Release of TNF-alpha during stent implantation into saphenous vein aortocoronary bypass grafts and its relation to plaque extrusion and restenosis.

The reduction in plaque volume during stent implantation is associated with the release of particulate debris and plaque-derived soluble substances. We studied the potential release of the proinflammatory cytokine TNF-alpha into the coronary circulation and whether such release is related to the reduction in plaque volume and, possibly, a predictor for restenosis. In 18 male patients (n = 24 stents) with severe stenosis in a saphenous vein aortocoronary bypass graft (SVG), we used a distal balloon occlusion-aspiration device during stent implantation. The aspirate TNF-alpha levels were determined before and after stent implantation and related to the angiographic and intravascular ultrasound-assessed severity of stenosis and restenosis. We found that TNF-alpha is, indeed, released into the aspirate of stented SVG (9 +/- 1 and 28 +/- 3 pg/ml before and after stent implantation, respectively, P < 0.0001) and that such release is related to the reduction in plaque volume (r = 0.88, P < 0.0001) and associated with restenosis after 5 mo (r = 0.71, P = 0.001). The periprocedural release of plaque-derived TNF-alpha possibly represents the amount and activity of the atherosclerotic process and might be a predictor for restenosis.

Atherosclerosis↗
PubMed2006

The effect of growth hormone on the response of total and acylated ghrelin to a standardized oral glucose load and insulin resistance in children with Prader-Willi syndrome.

CONTEXT: Fasting levels of plasma ghrelins are grossly elevated in children with Prader-Willi syndrome (PWS). The cause of this elevation and the regulation of ghrelins in PWS is largely unknown. The regulatory role of individual nutritional components and of GH is not well characterized. OBJECTIVE: We investigated the influence of GH on acylated (aGhr) and total ghrelin (tGhr) concentrations before and after an oral glucose load, and on insulin resistance in PWS children. DESIGN, PATIENTS, AND INTERVENTIONS: In a clinical follow-up study, plasma ghrelins were measured during an oral glucose tolerance test, and parameters of insulin resistance were determined in 28 PWS children before and/or 1.18 (0.42-9.6) yr (median, range) after start of GH therapy (0.035 mg/kg body weight per day). MAIN OUTCOME MEASURES: Fasting and postglucose concentrations of aGhr and tGhr and homeostasis model assessment 2 insulin resistance were the main outcome measures. SETTING: The study was conducted in a single center (University Children's Hospital). RESULTS: High fasting [1060 +/- 292 (sd) pg/ml; n = 12] and postglucose trough (801 +/- 303 pg/ml; n = 10) tGhr concentrations in GH-untreated PWS children were found to be decreased in the GH-treated group (fasting 761 +/- 247 pg/ml, n = 24, P = 0.006; postglucose 500 +/- 176 pg/ml, n = 20; P = 0.006). In contrast, aGhr concentrations and insulin resistance were not changed by GH treatment. Both aGhr and tGhr concentrations were decreased by oral carbohydrate administration, independent of the GH treatment status. CONCLUSIONS: Our results indicate that, in PWS children, aGhr and tGhr are differentially regulated by GH.

Acylation↗
PubMed2006

Calpain-10 variants and haplotypes are associated with polycystic ovary syndrome in Caucasians.

PCOS is known to be associated with an increased risk of T2DM and has been proposed to share a common genetic background with T2DM. Recent studies suggest that the Calpain-10 gene (CAPN10) is an interesting candidate gene for PCOS susceptibility. However, contradictory results were reported concerning the contribution of certain CAPN10 variants, especially of UCSNP-44, to genetic predisposition to T2DM, hirsutism, and PCOS. By means of MALDI-TOF MS technique, we genotyped an expanded single nucleotide polymorphism panel, including the CAPN10 UCSNP-44, -43, -56, ins/del-19, -110, -58, -63, and -22 in a sample of 146 German PCOS women and 606 population-based controls. Statistical analysis revealed an association between UCSNP-56 and susceptibility to PCOS with an odds ratio (OR) of 2.91 (95% CI=1.51-5.61) for women carrying an AA genotype compared with GG. As expected, the 22-genotype of the ins/del-19 variant, which is in high linkage disequilibrium (r2=0.98) with UCSNP-56, was also significantly associated (OR=2.98, 95% CI=1.55-5.73). None of the additionally tested variants alone showed any significant association with PCOS. A meta-analysis including our study (altogether 623 PCOS cases and 1,224 controls) also showed significant association only with ins/del-19. The most common haplotype TGG3AGCA was significantly associated with a lower risk for PCOS (OR=0.487, P=0.0057). In contrast, the TGA2AGCA haplotype was associated with an increased risk for PCOS (OR=3.557, P=0.0011). By investigating a broad panel of CAPN10 variants, our results pointed to an allele dose-dependent association of UCSNP-56 and ins/del-19 with PCOS.

Adult↗
PubMed2006

Residence close to high traffic and prevalence of coronary heart disease.

AIMS: Long-term exposure to urban air pollution may accelerate atherogenesis and increase cardiopulmonary mortality. We aim to examine the relationship between the long-term residential exposure to traffic and prevalence of coronary heart disease (CHD). METHODS AND RESULTS: We used baseline data from the German Heinz Nixdorf RECALL study, a population-based, prospective cohort study. For 3399 participants from two cities, we assessed the long-term personal traffic exposure and background air pollution, comparing residents living within 150 m of major roads with those living further away. The principal outcome variable was clinically manifest CHD. We evaluated the association with multivariable logistic regression, controlling for background air pollution and individual level risk factors. Of 3399 participants, 242 (7.1%) had CHD. The crude odds ratio (OR) for prevalence of CHD at high traffic exposure was significantly elevated (1.62, 95%CI 1.12-2.34) and rose to 1.85 (95%CI 1.21-2.84) after adjusting for cardiovascular risk factors and background air pollution. Subgroup analysis showed stronger effects for men (OR 2.33, 95%CI 1.44-3.78), participants younger than 60 years (OR 2.67, 95%CI 1.24-5.74) and never-smokers (OR 2.72, 95%CI 1.40-5.29). CONCLUSION: This study provides epidemiological evidence that the long-term exposure to traffic-related emissions may be an important risk factor for CHD.

Aged↗
PubMed2006

Thyrotropin receptor autoantibodies are independent risk factors for Graves' ophthalmopathy and help to predict severity and outcome of the disease.

OBJECTIVE: The objective of this study was to examine whether TSH-receptor antibody [TSH binding inhibitory antibodies (TBII)] levels are associated with the severity of Graves' ophthalmopathy (GO) over the entire course of the disease. METHODS AND PATIENTS: A total of 159 patients with GO were followed for 12-24 months. One year after the first symptoms of GO, all patients were classified into mild or severe GO according to their clinical manifestations. TBII were measured every 3 months after onset of GO. Receiver operating characteristic plot analysis was performed to assess the power to discriminate both patient groups by TBII (specificity >90%). RESULTS: TBII levels and prevalence at each time point during follow-up were significantly higher in patients with a severe course of GO compared with patients with a mild course of GO. Prognostic statements on the course of the disease were possible for about half of the GO patients at all time points (except the first). If at first presentation and at consecutive time points TBII levels were less than 5.7, 2.6, 1.5, 1.5, 1.5, and 1.5 IU/liter, the patients had a 2.3- to 15.6-fold higher chance of a mild course. If 5-8 months after GO onset and at consecutive time points TBII levels were above 8.8, 5.1, 4.8, 2.8, and 2.8 IU/liter, the patients had a 8.7- to 31.1-fold higher risk of a severe course. This relationship of TBII to the severity was independent from age and smoking. CONCLUSION: Follow-up measurements of TBII allow, in half of the patients, assessment of the prognosis of GO and, therefore, could be of additional help for the disease management.

Antithyroid Agents↗
PubMed2006

Prognostic value of preoperative cardiac troponin I in patients undergoing emergency coronary artery bypass surgery with non-ST-elevation or ST-elevation acute coronary syndromes.

BACKGROUND: Cardiac troponin I (cTnI) is a highly sensitive and specific biomarker which has been shown to predict patient outcome pre- and postoperatively following elective coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict the outcome in patients undergoing emergency CABG with acute myocardial infarction (AMI) is currently unknown. METHODS AND RESULTS: A possible correlation between preoperative cTnI and in-hospital mortality and major adverse cardiac events (MACE) was investigated in 57 patients with ST-elevation AMI (STEMI) in group 1 and 197 with Non-ST-elevation AMI (NSTEMI) in group 2, who were operated within 24 hours after onset of symptoms. Primary study end point was all-cause in-hospital mortality. Secondary end points were low cardiac output syndrome (LCOS) and hospital course. CTnI levels on admission were higher in group 1 compared with group 2 (7.1+/-1.8 versus 1.4+/-1.8 ng/mL; P<0.001). Overall in-hospital mortality was higher in group 1 compared with group 2 (14.3 versus 4.1%; odds ratio [OR], 3.9, 95% confidence interval [CI], 1.3 to 12.3; P<0.01). LCOS occurred in 16/57 (28.1%), and 18/197 (9.1%) patients, respectively (OR, 3.9, 95% CI, 1.7 to 8.8; P<0.001). Postoperative ventilation time, intensive care, and hospital stay were significantly longer in group 1 versus group 2. Multivariate logistic regression analyses revealed preoperative cTnI as the strongest independent predictor for in-hospital mortality (P<0.001) and MACE (P<0.001) in all AMI patients, regardless whether ST-elevation was included as an additional risk factor or not. CONCLUSIONS: Preoperative cTnI measurement before emergency CABG appears as a powerful and independent determinant of in-hospital mortality and MACE in acute STEMI and NSTEMI.

Aged↗
PubMed2006

C-terminal amino acid alteration rather than late termination causes complete deficiency of thyroxine-binding globulin CD-NeuIsenburg.

CONTEXT: T(4)-binding globulin (TBG) is the main transport protein for T(4) in blood and a member of the superfamily of serine proteinase inhibitors. So far, 14 mutations leading to familial complete TBG deficiency have been reported. Eleven of these are caused by mutations leading to truncation of the molecule, and three are caused by single amino acid substitutions. OBJECTIVE: We report and study the complete deficiency TBG variant found in a patient from NeuIsenburg, Germany (TBG-CDNI). METHODS: Direct DNA sequencing was used to identify the TBG-CDNI mutation in the propositus, which was confirmed by allele-specific amplification. Site-directed mutagenesis and expression in Xenopus oocytes was used to study the secretion defect of TBG-CDNI and several variants by Western blot and T(4)-binding assay. RESULTS: The deletion of two nucleotides in codon 384 (1211_1212delTC) causes a frameshift altering the last 11 residues, introduces a new glycosylation site, and elongates the molecule by seven new amino acids. In contrast to normal TBG, TBG-CDNI was not secreted by Xenopus oocytes. Elongation of normal TBG by seven alanines did not affect its secretion or binding properties. On the other hand, neither disruption of its new glycosylation site nor termination of TBG-CDNI at the normal length repaired its secretion defect. CONCLUSIONS: In this first late termination variant of complete TBG deficiency, alteration of beta-strand 5B, located in the core of the molecule, rather than elongation of the molecule or introduction of a new glycosylation site, suffices to disrupt secretion of TBG-CDNI.

Adult↗
PubMed2006

[Diagnosis and therapy of endocrine hypertension].

Once the diagnosis of hypertension is established, secondary forms should be considered. Especially hormonally active adrenal tumors may allow specific treatment. For primary hyperaldosteronism plasma aldosterone to active renin concentration ratio in patients with plasma aldosterone levels > or = 200 ng/l is a reliable screening method under random conditions. A salt loading test may confirm a primary aldosteronism. A unilateral adrenal adenoma has to be separated from bilateral adrenal hyperplasia. To exclude Cushing's syndrome, the dexamethasone challenge is a reliable screening parameter. Patients with Cushing's syndrome may have an elevated urinary free cortisol and the circadian rhythm may be abolished resulting in an elevated 23:00 h serum cortisol. Alternatively, cortisol may be measured in saliva using specific cutoffs. Determinations of 24-h urinary epinephrine and norepinephrine levels are established diagnostic tools for the diagnosis of pheochromocytoma. Metanephrines, which are metabolites of catecholamines, have been suggested as an alternative more sensitive and specific diagnostic tool. In conclusion, recently established biochemical methods are reliable screening parameters for the diagnosis of adrenal hypertension. Endocrine hypertension due to adrenal tumors may be treated by minimally invasive surgery or specific antihypertensive treatment.

Adrenal Gland Neoplasms↗
PubMed2006

Metformin treatment of polycystic ovary syndrome improves health-related quality-of-life, emotional distress and sexuality.

BACKGROUND: In polycystic ovary syndrome (PCOS), changes in physical appearance, menstrual disturbances and infertility result in psychological distress and reduced quality-of-life. Metformin improves biochemical, clinical and reproductive parameters in PCOS women. In a prospective, observational study, we analysed the effects of metformin treatment on health-related quality-of-life (HRQL), emotional well-being and sexuality in PCOS. No placebo-treated control group was included. METHODS: Before, during and after 6 months of treatment, changes in clinical and endocrine parameters, quality-of-life, psychological disturbances and sexuality were assessed in 64 PCOS patients using validated questionnaires (SF-36, SCL-90-R) and visual analogue scales. Patients were also compared with published normative data for the validated questionnaires. RESULTS: During treatment, HRQL, particularly the psychosocial aspects (indicated by significant increases in SF-36 scales Vitality, Social Function, Emotional Role Function, Mental Health, Psychological Sum scale) and emotional well-being (reflected by significant lowering of SCL-90-R scales) improved. These improvements in HRQL were significantly correlated with a reduction in body weight and significantly more pronounced in patients with normalized menstrual cycles. In addition, PCOS women were significantly more satisfied with their sex life and reported higher frequencies of sexual intercourse following treatment. CONCLUSION: Treatment can improve the psychosocial, emotional and psychosexual situation of PCOS patients. Although at least some of these effects may be related to the reduction of individual clinical symptoms (i.e. weight loss, normalization of menstrual disturbances, improvement of acne), this observational study does not allow us to clearly discern the role of symptom constellation and does not preclude non-specific and/or placebo effects. Nevertheless, emotional distress and reduced quality-of-life are clearly not an inevitable consequence of PCOS and should be considered as adjunct treatment goals in future studies.

Adult↗
PubMed2006

Determinants of emotional distress in women with polycystic ovary syndrome.

BACKGROUND: The goals were to analyse the incidence of mental distress in women with untreated polycystic ovary syndrome (PCOS) using self-report measures, to characterize PCOS patients at risk for psychiatric disease with regard to sociodemographic and clinical characteristics, and to assess the impact of emotional distress on quality of life. METHODS AND RESULTS: Complete metabolic, hormonal, clinical and self-report psychological data [emotional distress, Symptom Check List 90 (SCL-90-R); quality of life, Short-Form Health Survey 36 (SF-36); sexual satisfaction, visual analogue scales; sociodemographic data] were obtained from n = 143 untreated women with PCOS. Prior psychiatric diagnoses were exclusionary. Twenty-two patients (15.4%) had a possible psychological disorder, based on SCL-90-R global severity index (GSI) scores > or =63 (SCL cases). SCL cases had significantly elevated body mass index (BMI), but did not differ from SCL non-cases in other clinical, endocrine, metabolic or sociodemographic variables. Stepwise multiple regression analyses identified GSI as a significant predictor of SF-36 Psychological Sum score, along with age and current wish to conceive (R2 = 0.47); the SF-36 Physical Sum score was predicted by BMI and education (R2 = 0.27), but not GSI. CONCLUSIONS: Psychiatric illness may go undetected in a proportion of PCOS patients. Although the majority of patients exhibit subclinical levels of psychological disturbances, emotional distress together with obesity lead to large decrements in quality of life in PCOS.

Adult↗
PubMed2006

Coronary atherosclerosis and cardiovascular risk in masters male marathon runners. Rationale and design of the "marathon study".

BACKGROUND: Regular physical exercise is recommended to reduce cardiovascular mortality. And yet, atherosclerosis is the main cause of exercise-associated death in persons beyond age 35. The need for risk stratification in marathon runners is under discussion. The predictive value of modern imaging- and non-imaging-based markers of risk that can be used for risk stratification in masters endurance athletes still deserves exploration. METHODS: Male runners > 50 years who have completed at least five marathon races during the preceding 3 years and do not suffer from coronary artery disease, angina nor diabetes mellitus are studied to assess the predictive value of established and modern imaging- based and biochemical cardiovascular risk factors. Laboratory parameters including clinical chemistry, hematology and hormone measurements are determined. Lifestyle-related risk factors, psychosocial and socioeconomic variables are explored using standardized questionnaires. Coronary, carotid, femoral and aortic atherosclerosis is measured using electronbeam computed tomography and ultrasound. In addition, a resting ECG, a bicycle stress test and heart rate variability are performed. Myocardial morphology and function are assessed using echocardiography and magnetic resonance imaging. Participants are invited to compete in a marathon race to quantify the association of coronary atherosclerosis with marathon-related changes of cardiac troponin levels and the extent of marathon-induced inflammation. At the cellular level, the effect on the amount of circulating progenitor cells (EPCs) is determined by FACS analysis. Changes in laboratory parameters and hormone levels are also studied. Annual long-term follow-up including hospital records and death certificates is performed. Data are compared with those from a general unselected cohort from the Heinz Nixdorf Recall Study. CONCLUSION: This study should contribute to cardiovascular risk assessment in the growing number of masters marathon runners with a focus on assessing the predictive value of modern imaging techniques and biochemical markers for comprehensive risk stratification.

Adult↗
PubMed2006

Laparoscopic and retroperitoneoscopic treatment of pheochromocytomas and retroperitoneal paragangliomas: results of 161 tumors in 126 patients.

BACKGROUND: Laparoscopic and retroperitoneoscopic excisions of pheochromocytomas and retroperitoneal paragangliomas are challenging surgical procedures because of extensive intraoperative catecholamine release, extreme vascularization, and demanding localization. MATERIALS: In a prospective clinical study 161 chromaffine neoplasias (134 pheochromocytomas, 27 paragangliomas) were removed endoscopically in 126 patients (67 males, 59 females, age 41.7 +/- 16.4 years; 130 operations). Six patients showed multiple (2-5) tumors. Tumor size ranged from 0.5 to 12 cm (mean 3.5 +/- 1.9 cm). Forty-two patients suffered from hereditary diseases. Twenty-four patients had bilateral adrenal diseases; in 14 patients pheochromocytomas were removed on both sides synchroneously. Ten neoplasias were local or loco-regional recurrences (7 pheochromocytomas, 3 paragangliomas). The laparoscopic route was chosen in 16 operations; the retroperitoneoscopic technique was performed in 128 others. Partial adrenalectomies were performed in 57 operations (in all but one of the patients with bilateral disease). High-dosage alpha-blockade with phenoxybenzamine was routinely used. RESULTS AND DISCUSSION: Conversion to open surgery occurred once. Perioperative complications were minor (17%); mortality was zero. Operating time for unilateral retroperitoneoscopically removed primary pheochromocytomas (n = 113) was 82 +/- 49 minutes (range: 20-300 minutes) and depended on tumor size (< 3 cm vs. > or = 3 cm; P < 0.05) and gender (P < 0.001), but not on extent of resection (partial vs. total, P = 0.266). Operating time for paragangliomas ranged from 55 to 600 minutes. Median blood loss was 20 ml. Median duration of postoperative hospitalization was 4 days. In 22 of 24 patients with bilateral disease, complete preservation of cortical function was achieved. Locoregional and/or distant metastatic recurrence were found in 5 patients. CONCLUSIONS: Endoscopic removal of solitary, bilateral, multiple, and recurrent pheochromocytomas and retroperitoneal paragangliomas is feasible and safe, but surgeons need extensive experience in minimally invasive techniques, as well as in endocrine surgery.

Adolescent↗
PubMed2006

Posterior retroperitoneoscopic adrenalectomy--results of 560 procedures in 520 patients.

BACKGROUND: The posterior retroperitoneoscopic adrenalectomy is less popular than the laparoscopic transabdominal method. Due to the direct approach to the adrenal glands, however, the posterior retroperitoneal access is easy to use and may offer advantages not available with other endoscopic procedures for adrenalectomy. METHODS: Between July 1994 and March 2006, we performed 560 adrenalectomies (right side: n = 258; left side: n = 302) by the posterior retroperitoneoscopic approach in 520 patients (200 male, 320 female; age, 10 to 83 years). Of the 520 patients, 21 suffered from Cushing's disease, 499 patients had adrenal tumors (157 Conn's adenomas, 120 pheochromocytomas [13 bilateral], 110 Cushing's adenomas [6 bilateral], and 112 other tumors). Tumor size ranged from 0.5 to 10 cm (mean, 2.9 +/- 1.7 cm). The procedures were performed with the patients in the prone position usually with 3 trocars. RESULTS: Mortality was zero. Conversions to open or laparoscopic lateral surgery were necessary in 9 patients (1.7%). Major complications occurred in 1.3% of patients, minor complications in 14.4%. Mean operating time was 67 +/- 40 min and declined significantly (P < .001) from the early procedures (106 +/- 46 min) to the later operations (40 +/- 15 min). CONCLUSIONS: The posterior retroperitoneoscopic adrenalectomy is a safe and fast procedure. In experienced hands, this method represents the ideal approach in adrenal surgery.

Adolescent↗
PubMed2006

Appropriateness of therapeutic drug monitoring for antidepressants in routine psychiatric inpatient care.

Although there is sufficient evidence of the benefits of therapeutic drug monitoring (TDM) for optimizing antidepressant therapy, its current use in routine care is far from optimal. As a prerequisite for developing improvement strategies, the appropriateness of TDM use was investigated in a psychiatric hospital in which TDM is applied routinely to a large extent. A retrospective analysis of all patients admitted in 2003 with a unipolar depressive disorder was performed. Based on detailed chart review, for all TDM tests, the time of blood sample taking in relation to the medication process and the consequences of the TDM results for clinical decision making were analyzed. Altogether, 748 plasma levels were measured for antidepressants. The evaluation identified considerable inappropriate use of TDM. After a preceding change of dose, only the minority of TDM tests was performed within an optimum time interval. Overall, 30% of blood samples were taken too early, before steady state had been reached. The high number of repeat tests without preceding change of drug dose points to potentially redundant use. There also was evidence of underuse of TDM, as in many cases additional plasma level determinations might have been useful to speed up optimal dosing. Frequent discrepancies were found between the laboratory's recommendations and actual clinical decision making. Suggested dose changes were followed in only 30%. The findings clearly indicate the need for measures to improve the implementation of TDM in routine care. Based on the identified pattern of current TDM utilization and experiences from other fields of medicine, a combination of strategies, including both educational and electronic interventions, may have the greatest potential for improvement.

Adult↗
PubMed2006

Diagnostic value of biochemical parameters in the differential diagnosis of an adrenal mass.

In patients with an adrenal mass, hormonally active tumors including pheochromocytomas as well as aldosterone- and cortisol-secreting adenomas need to be considered. Several studies have demonstrated that metanephrines, which are the metabolites of catecholamines, are reliable parameters for the diagnosis of pheochromocytoma. In patients with an adrenal mass, we found plasma metanephrines, measured by a newly available radioimmunoassay, to be highly sensitive and specific for pheochromocytomas, with a better accuracy than any other biochemical parameter. The plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio is an established screening tool for primary hyperaldosteronism. However, determination of active renin concentration (ARC) in contrast to PRA may offer advantages in regard to processing and standardization. We found a PAC to ARC ratio of >62 in patients with PAC levels>200 ng/L to be a reliable screening method for primary hyperaldosteronism in patients with adrenal masses. The screening for hypercortisolism relies on excess urinary cortisol secretion, loss of the physiological feedback during dexamethasone challenge, and loss of the circadian rhythm. Because urinary-free cortisol may not identify subclinical Cushing's syndrome, in which hypercortisolism is still mild, the 1-mg dexamethasone suppression test has been recommended in all patients with incidentally detected masses. Alternatively, late-night cortisol levels in saliva have been found to have a high sensitivity and specificity for the diagnosis of Cushing's syndrome. In summary, in patients with an adrenal mass, hormonally active adrenal tumors can be excluded with high certainty using a few highly reliable biochemical parameters.

Adrenal Gland Neoplasms↗
PubMed2006

Decreased soluble leptin receptor levels in women with polycystic ovary syndrome.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is associated with insulin resistance and a high incidence of obesity. Leptin, the product of the ob gene, is involved in the regulation of energy balance and obesity and circulates in both free and bound forms. The soluble leptin receptor (sOB-R) is the most important leptin-binding protein, thus influencing the biologically active free leptin level. DESIGN: We assessed the correlation of metabolic and endocrine parameters with leptin and sOB-R levels in 122 PCOS women (aged 27 +/- 5.7 years) and 81 healthy controls (aged 25 +/- 4.0 years). METHODS: Leptin and sOB-R levels were measured using ELISA kits. In addition, anthropometric variables, body fat and endocrine parameters were evaluated and a glucose tolerance test performed to assess indices of insulin resistance and glucose metabolism. RESULTS: In PCOS patients, no correlation was found between leptin or sOB-R and parameters of hyper-androgenism. However, as expected, body mass index (BMI), body fat, waist circumference and indices of insulin resistance were significantly correlated with leptin in PCOS subjects and controls. In a subgroup analysis of lean, overweight and obese PCOS patients, significant differences were found in leptin (29.7 +/- 20.7 vs 45.4 +/- 25.0 vs 67.7 +/- 28.8 ng/ml, P < 0.0001) and sOB-R (8.0 +/- 3.4 vs 6.4 +/- 2.5 vs 5.7 +/- 2.3 ng/ml, P < 0.05). Compared with BMI-matched controls, lean PCOS patients had lower sOB-R levels (8.0 +/- 3.4 vs 12.7 +/- 4.7 ng/ml, P < 0.0001) and higher free leptin indices (4.5 +/- 3.9 vs 2.8 +/- 2.2, P = 0.0285). CONCLUSION: Taking into account that low sOB-R levels supposedly compensate diminished leptin action, PCOS per se might cause leptin resistance.

Adult↗
PubMed2006

Diagnostic value of various biochemical parameters for the diagnosis of pheochromocytoma in patients with adrenal mass.

OBJECTIVE: Pheochromocytomas are neoplasms generally characterized by the autonomous production of catecholamines. This study compared various biochemical parameters for the diagnosis of adrenal pheochromocytoma in patients with adrenal mass. DESIGN: One hundred and fifty subjects were studied, including 24 histologically proven pheochromocytomas, 17 aldosterone-secreting and 21 cortisol-secreting adrenal adenomas and 30 nonfunctioning adrenal masses, 16 patients with essential hypertension and 42 healthy normotensive volunteers. Spontaneous blood samples and 24-h urine samples were collected prospectively. METHODS: Plasma and urinary epinephrine and norepinephrine levels were measured by high performance liquid chromatography, whereas plasma and urinary metanephrine and normetanephrine levels were determined by radioimmunoassay (RIA). Putative ratio thresholds were calculated by receiver operating characteristic (ROC) analysis to balance between sensitivity and specificity. RESULTS: Plasma normetanephrine was found to be the best single parameter with the highest sensitivity (91.7%) and specificity (95.6%) using a threshold of 126 pg/ml. In combination, plasma normetanephrine and metanephrine had a higher sensitivity of 95.8% with lower specificity (79.4%). All other combinations of plasma and/or urinary parameters demonstrated a lower accuracy. CONCLUSION: Plasma metanephrines measured by RIA are reliable screening parameters for the diagnosis of pheochromocytoma.

Adrenal Gland Neoplasms↗