Validity of free testosterone calculation in pregnant women.

Objective Increased maternal testosterone concentration during pregnancy may affect the fetus. Therefore it is clinically relevant to have a quick and reliable method to determine free testosterone levels. Current calculators for free testosterone are suspected to perform poorly during pregnancy due to suggested competition between high levels of estradiol and free (bio-active) testosterone for sex hormone-binding globulin (SHBG) binding. Therefore, it is claimed that reliable calculation of free testosterone concentration is not possible. However, recent evidence on SHBG-binding sites questions the estradiol effect on the testosterone-SHBG binding during pregnancy. In this study, we investigated whether the free testosterone concentration can be calculated in pregnant women. Design and methods Free testosterone was measured with a specially developed equilibrium dialysis method combined with liquid chromatography tandem mass spectrometry (LC-MS/MS). Free testosterone was also calculated with the formulas of Vermeulen et al. and Ross et al. Results Total and free testosterone measured in healthy men and women were in good agreement with earlier reports. In pregnant women, total testosterone values were higher than in non-pregnant women, whereas free testosterone values were comparable. Calculated free testosterone levels in pregnant women were highly correlated, but marginally higher, compared to measured free testosterone levels. Conclusions We developed an equilibrium dialysis-LC-MS/MS method for the measurement of free testosterone in the low range of pregnant and non-pregnant women. Although during pregnancy total testosterone is increased, this is not the case for free testosterone. The free testosterone formulas perform well in pregnant women.

Monitoring hypoxia and vasculature during bevacizumab treatment in a murine colorectal cancer model.

The purpose of this study was to assess the effect of bevacizumab on vasculature and hypoxia in a colorectal tumor model. Nude mice with subcutaneous LS174T tumors were treated with bevacizumab or saline. To assess tumor properties, separate groups of mice were imaged using (18) F-Fluoromisonidazole (FMISO) and (18) F-Fluorodeoxyglucose (FDG) positron emission tomography or magnetic resonance imaging before and 2, 6 and 10 days after the start of treatment. Tumors were harvested after imaging to determine hypoxia and vascular density immunohistochemically. The T2 * time increased significantly less in the bevacizumab group. FMISO uptake increased more over time in the control group. Vessel density significantly decreased in the bevacizumab-treated group. The Carbonic anhydrase 9 (CAIX) and glucose uptake transporter 1 (GLUT1) fractions were higher in bevacizumab-treated tumors. However, the hypoxic fraction showed no significant difference. Bevacizumab led to shorter T2 * times and higher GLUT1 and CAIX expression, suggesting an increase in hypoxia and a higher glycolytic rate. This could be a mechanism of resistance to bevacizumab. The increase in hypoxia, however, could not be demonstrated by pimonidazole/FMISO, possibly because distribution of these tracers is hampered by bevacizumab-induced effects on vascular permeability and perfusion.

Harmonization of growth hormone measurement results: the empirical approach.

Growth hormone (hGH) is a measurand belonging to ISO category 4, indicating intrinsic unavailability of a reference measurement procedure and primary standard material. Large between-method differences have been raising confusion, especially in the interpretation of results of stimulation tests for exclusion of juvenile growth hormone deficiency. Within the framework of the external quality assessment scheme (EQAS) of the SKML (Dutch Foundation for Quality Assessment in Clinical Laboratories), attempts to reduce between-method variation of hGH measurements have been made, starting in 1994 with an inter-laboratory comparison of 9 different immunoassays by using a panel of sera and standard materials available at that time. Methods appeared to differ from each other largely in a systematic, sample-independent manner. These systematic differences are reflected in the hGH measurement results obtained in commutable sera. A commutable serum pool was introduced as a consensus reference material, permitting correction of each method's results to a common scale. Pair wise comparisons ("twin studies") were carried out to investigate and corroborate the effectiveness of this material for harmonization. A significant reduction of the between-laboratory coefficient (CV) of variation from 22 to 9.0% was attained.

Ten-year analysis of the prospective multicentre Chemo-N0 trial validates American Society of Clinical Oncology (ASCO)-recommended biomarkers uPA and PAI-1 for therapy decision making in node-negative breast cancer patients.

AIM: Final 10-year analysis of the prospective randomised Chemo-N0 trial is presented. Based on the Chemo-N0 interim results and an European Organisation for Research and Treatment of Cancer (EORTC) pooled analysis (n=8377), American Society of Clinical Oncology (ASCO) and Arbeitsgemeinschaft Gynäkologische Onkologie (AGO) guidelines recommend invasion and metastasis markers urokinase-type plasminogen activator (uPA)/plasminogen activator inhibitor-1 (PAI-1) for risk assessment and treatment decision in node-negative (N0) breast cancer (BC). METHODS: The final Chemo-N0 trial analysis (recruitment 1993-1998; n=647; 12 centres) comprises 113 (5-167) months of median follow-up. Patients with low-uPA and PAI-1 tumour tissue levels (n=283) were observed. External quality assurance guaranteed uPA/PAI-1 enzyme-linked immunosorbent assay (ELISA) standardisation. Of 364 high uPA and/or PAI-1 patients, 242 agreed to randomisation for CMF chemotherapy (n=117) versus observation (n=125). RESULTS: Actuarial 10-year recurrence rate (without any adjuvant systemic therapy) for high-uPA/PAI-1 observation group patients (randomised and non-randomised) was 23.0%, in contrast to only 12.9% for low-uPA/PAI-1 patients (plog-rank=0.011). High-risk patients randomised to cyclophosphamide-methotrexate-5-fluorouracil (CMF) therapy had a 26.0% lower estimated probability of disease recurrence than those randomised for observation (intention-to-treat (ITT)-analysis: hazard ratio (HR) 0.74 (0.44-1.27); plog-rank=0.28). Per-protocol analysis demonstrated significant treatment benefit: HR 0.48 (0.26-0.88), p=0.019, disease-free survival (DFS) Cox regression, adjusted for tumour stage and grade. CONCLUSIONS: Chemo-N0 is the first prospective biomarker-based therapy trial in early BC defining patients reaching good long-term DFS without adjuvant systemic therapy. Using a standardised uPA/PAI-1 ELISA, almost half of N0-patients could be spared chemotherapy, while high-risk patients benefit from adjuvant chemotherapy. These 10-year results validate the long-term prognostic impact of uPA/PAI-1 and the benefit from adjuvant chemotherapy in the high-uPA/PAI-1 group at highest level of evidence. They thus support the guideline-based routine use of uPA/PAI-1 for risk-adapted individualised therapy decisions in N0 breast cancer.

Monitoring the effects of bevacizumab beyond progression in a murine colorectal cancer model: a functional imaging approach.

Clinical studies have shown that bevacizumab beyond progression to first line therapy is beneficial for overall survival in advanced stage colorectal cancer. We studied the utility of several functional imaging modalities to assess the efficacy of bevacizumab beyond progression (BBP). All BALB/c mice with s.c. LS174T xenografts were treated with capecitabine, oxaliplatin and bevacizumab combination therapy. Tumor volume was assessed using caliper measurements. Increase of 1.5 times the initial volume on two subsequent measurements, was considered progression. In half of the mice bevacizumab treatment was continued (n = 13) after progressive disease was established, while the others received saline injections (n = 12). Within 3 days after progression, multi-modal imaging was performed using FDG-PET, diffusion weighted imaging, T2* and dynamic contrast enhanced MRI. Measurements were repeated 7 and 10 days after the first measurements. Afterwards, tumors were analyzed for expression of carbonic anhydrase IX, glucose transporter 1, 9 F1 to stain the vasculature and Ki67 to assess proliferation. In the BBP group tumor growth after progression was reduced compared to the control group (p < 0.01). FDG-PET showed a trend towards lower FDG uptake in the BBP group (p = 0.08). DWI, T2* and DCE-MRI parameters were not significantly different between both groups. The immunohistochemical analyses showed higher CAIX-positive fraction (p < 0.01) and lower Ki67 expression (p = 0.06) in the BBP group. The relative vascular area was significantly lower in the BBP group (p = 0.03). GLUT-1 expression and vascular density did not significantly differ between both groups. Bevacizumab after progression resulted in significant changes in the tumor proliferation and microenvironment compared to discontinuation of bevacizumab. FDG-PET may be sensitive to BBP-induced effects.

Menopausal status and adjuvant hormonal therapy for breast cancer patients: a practical guideline.

Breast cancer is the most common malignancy amongst women in the developed world. For patients with hormone-sensitive breast cancer eligible for adjuvant hormonal therapy, it is important to know if the ovaries are (still) functional or not. Indeed, the choice for a specific adjuvant hormonal treatment depends on the menopausal status of an individual woman. The currently available measures to determine the menopausal status are conflicting. Until better measures become available, we propose a practical guideline enabling an optimal choice of adjuvant hormonal therapy for women with a hormone receptor positive breast cancer taking into account uncertainties about their menopausal status.

Bilateral thoracoscopic splanchnicectomy for pain in patients with chronic pancreatitis impairs adrenomedullary but not noradrenergic sympathetic function.

BACKGROUND: Bilateral thoracoscopic splanchnicectomy (BTS) is a well-known technique to alleviate intractable pain in patients with chronic pancreatitis. BTS not only disrupts afferent fibers from the pancreas that mediate pain but also postganglionic sympathetic fibers, which originate in segments T5-T12 and which innervate the vasculature of the liver, pancreas, and the adrenal gland. The purpose of this study was to assess whether and how BTS affects sympathetic noradrenergic and adrenomedullary function in patients with chronic pancreatitis. METHODS: Sixteen patients with chronic pancreatitis for at least 1 year underwent autonomic function testing before and 6 weeks after BTS for intractable pain. Testing was performed during supine rest and during sympathetic stimulation when standing. RESULTS: Supine and standing systolic and diastolic blood pressure were significantly lower post-BTS compared with pre-BTS (P = 0.001). One patient showed orthostatic hypotension after BTS. Baseline plasma norepinephrine levels and plasma norepinephrine responses to sympathetic activation during standing were not reduced by BTS. In contrast, supine plasma epinephrine levels and responses during standing were significantly reduced (P < 0.001). Parasympathetic activity was unaffected by BTS as shown by unaltered Valsalva ratio, I-E difference, and ΔHRmax. CONCLUSIONS: BTS for pain relief in patients with chronic pancreatitis reduced adrenomedullary function, due to disruption of the efferent sympathetic fibers to the adrenal gland. BTS did not affect noradrenergic sympathetic activity, although blood pressure was lower after the sympathectomy.

Increased sympathetic activity in chronic pancreatitis patients is associated with hyperalgesia.

Pain treatment in chronic pancreatitis patients is difficult, with pain frequently relapsing or persisting. Recent studies suggest that altered central nervous system pain processing underlies the chronic pain state in these patients. There is evidence that increased sympathetic activity may also play a role in some chronic pain syndromes. This study assessed sympathetic nervous system activity and its relation to pain processing in patients with severe painful chronic pancreatitis. The authors postulated that chronic pancreatitis patients with more sympathetic activity exhibit more generalized hyperalgesia. In 16 chronic pancreatitis patients, sympathetic activity was measured via venous plasma norepinephrine (NE) levels (supine, standing). Pain processing was quantified via pressure pain tolerance thresholds (PPTs) in dermatomes T10 (pancreatic area), C5, T4, L1. Five patients showed increased supine plasma NE levels (NE ≥ 3.0 nmol/L). PPTs were lower in patients with increased NE levels (INE) compared with patients with normal NE (NNE) (means [95% confidence interval]: INE 402 kPa [286-517] versus NNE 522 kPa [444-600]; P = .042). In severe chronic pancreatitis patients, increased sympathetic activity and hyperalgesia appear associated, suggesting that sympathetic activity may also play a role in these patients' pain.

Placental urocortin-2 and -3: endocrine or paracrine functioning during healthy pregnancy?

OBJECTIVES: Placental urocortins may affect uterine quiescence by modulating in an endocrine or paracrine way the estradiol secretion by the adjacent placenta. The aim of this study was to investigate the role of placental urocortin-2 and -3 as endocrine or as auto/paracrine messengers in concert with placental estradiol generation. STUDY DESIGN: In a cross-sectional study, plasma was obtained from healthy pregnant women, between 10 and 42 gestational weeks, and from nonpregnant women. Third trimester plasma pools were used for urocortin-2 and -3 peptide characterization by HPLC and RIA. Plasma samples (gestational age 10 and 42 wk) were analyzed using validated radioimmunoassays specific for urocortins and corticotropin-releasing factor (CRF). To reveal possible local actions of urocortins the influence of urcortin-2 on the estradiol secretion from placental tissue cultures was investigated. RESULTS: Reversed-phase HPLC fractionation of plasma extracts revealed several peaks containing immunoreactive-like urocortin-2 or -3, of which the main peaks had the same retention time as the synthetic urocortin-2 or -3 peptides. In contrast to plasma CRF, no gestational age dependent changes in plasma urocortin-1, -2 and -3 levels occurred. The mean plasma urocortin levels during gestation did not differ from postpartum levels. In vitro, urocortin-2 stimulated dose-dependently the placental estradiol secretion, a stimulation inhibited by antisauvagine-30, a CRF-receptor 2 antagonist. CONCLUSION: Placentas of healthy pregnant women do not, or not to any great extent, secrete urocortin-2 and -3 in the plasma. We show that urocortins can regulate the estradiol secretion from placental tissue cultures via the CRF-R2 mediated pathway. Therefore, placental urocortin-2 and -3 peptides are more likely to function as auto/paracrine messengers during healthy pregnancy, than as endocrine messengers.

[Application of tumour markers in clinical practice]. / Toepassing van tumormarkers in de klinische praktijk.

Usefully requesting and applying serum tumour markers in diagnosis and treatment can be difficult. It should be noted that tumour markers are used for varying purposes: screening, diagnosis, staging and prognostic evaluation, detection of recurrence and treatment monitoring. Due to the poor sensitivity and specificity of current tumour markers, most are not suitable for screening an asymptomatic population. Further, the benefits of an improved prognosis by early detection should be weighed against a poorer quality of life and the cost of substantial over-diagnosis and over-treatment. Serum tumour markers are particularly applicable in treatment monitoring and detection of recurrence. Sometimes they can be used to support the diagnostic process and give useful prognostic information.

Placental urocortins and CRF in late gestation.

Placental corticotropin-releasing factor (CRF) are thought to induce labor via activation of CRF receptor type 1 (CRF-R1) leading to several feed forward mechanisms in the placental, fetal and maternal compartments. Recently, receptor type 2 (CRF-R2) selective ligands called urocortin 2 and 3 (Ucn 2, Ucn 3) were characterized as neuropeptides in the brain. We studied the expression of Ucn 1, 2 and 3 in feto-placental tissues qualitatively (by immunohistochemistry) and quantitatively (by radioimmunoassay) and compared these with expression of placental CRF. The presented placental Ucn 2 and 3 peptide quantification, characterization and ex-vivo release results are novel. Reversed-phase HPLC fractionation of placental extracts revealed several peaks containing immune-reactive (ir)-like Ucn 2 or 3, of which the main peaks had the same retention time as the synthetic Ucn 2 and 3 peptides. Placental tissues contained between 6 and 10 times more ir-CRF than ir-Ucn 1, 2 or 3. The placental Ucn 1, 2 and 3 peptide contents correlated with each other. Our immunohistochemical results showed that all urocortins were mainly localized in the syncytiotrophoblasts of the placental villi. Placental urocortins were actively released during ex-vivo perfusion of cotyledons. From these results it can be concluded that Ucn 2 and 3 peptides are present in placental and fetal membrane tissues, and released by ex-vivo perfused cotyledons. Therefore, placental urocortins may function as paracrine or endocrine messengers during pregnancy and parturition.

The relationship between central adrenal insufficiency and sleep-related breathing disorders in children with Prader-Willi syndrome.

BACKGROUND: The annual death rate of patients with Prader-Willi syndrome (PWS) is high (3%). Many deaths of children are sudden and unexplained. Sleep apneas have been suggested to play a role in sudden deaths. Recently, we discovered that 60% of patients with PWS suffer from central adrenal insufficiency (CAI) during stress. OBJECTIVE: The aim was to study the relationship between CAI and sleep-related breathing disorders. DESIGN: In 20 children with PWS who underwent a metyrapone test (30 mg/kg at 2330 h), sleep-related breathing was evaluated by polysomnography before the metyrapone test. In addition, we recorded sleep-related breathing in 10 children with PWS during their metyrapone test. CAI was diagnosed when ACTH levels during the metyrapone test were below 33 pmol/liter at 0730 h. All tests were performed during healthy condition. SETTING: The study was conducted in a pediatric intensive care unit and specialized sleep center. RESULTS: Median (interquartile range) age was 8.4 yr (6.5-10.2). After metyrapone administration, median (interquartile range) central apnea index (number/hour) increased significantly from 2.2 (0.4-4.7) to 5.2 (1.5-7.9) (P = 0.007). The increase tended to be higher in children with CAI [2.8 (2.0-3.9) vs. 1.0 (-0.2 to 2.6); P = 0.09]. During polysomnography before the metyrapone test, sleep-related breathing was worse in children with CAI, who had a significantly higher central apnea index and tended to have a lower minimum oxygen saturation compared to those without CAI (P = 0.03 and P = 0.07). CONCLUSIONS: In children with PWS, the central apnea index increased significantly after metyrapone administration, particularly in those with CAI during stress. In addition, children with CAI had a higher central apnea index compared to those without several months before the metyrapone test.

Gonadotropins and female sex steroid hormones in cyst fluid and serum from patients with ovarian tumors.

The objective of the present study was to determine the concentrations of LH, FSH, 17beta-estradiol and progesterone in ovarian cyst fluid and serum from patients with benign and malignant ovarian tumors and to assess the correlation of the gonadotropin and female sex steroid hormone concentrations with menopausal and tumor status. Ovarian cyst fluid and blood samples were prospectively collected from 103 patients with ovarian tumors. Seventy-four of the patients had benign ovarian tumors while 29 patients had malignant ovarian tumors. Malignant ovarian tumors showed significantly higher LH and FSH cyst fluid concentrations compared to concentrations from patients with benign tumors. Within the malignant subset, LH and FSH concentrations correlated with increasing FIGO stage and grade. Furthermore, LH and FSH cyst fluid concentrations showed strong correlations (r > 0.62) with serum concentrations in case of malignant tumors, especially in postmenopausal women, but not in case of benign tumors. The highest gonadotropin concentrations were observed in cyst fluid from malignant ovarian tumors. The most probable explanation for this is an increased vascular permeability within the cysts. Supportive evidence for such an increased vascular permeability is our previous finding of significantly higher VEGF concentrations in cyst fluid from malignant ovarian tumors. The possibility of ectopic production of LH and FSH by malignant ovarian tissue cannot completely be ruled out.

[Intraoperative parathyroid hormone measurement in patients with primary hyperparathyroidism; particularly valuable for suspected solitary parathyroid adenoma and re-operation]. / Intraoperatieve bepaling van parathormoon bij primaire hyperparathyreoïdie; vooral waardevol bij vermoeden van solitair bijschildklieradenoom en bij heroperatie.

OBJECTIVE: Analysis of the value of intraoperative parathormone (PTH) measurement in patients with primary hyperparathyroidism. DESIGN: Prospective study. METHOD: Evaluation of the value of intraoperative measurement ofPTH in 75 patients (including 19 patients with multiple endocrine neoplasia(MEN)-1 syndrome) who underwent parathyroidectomy in 2001-2005. RESULTS: The so-called Miami-criterion (PTH concentration 10 min after excision at least 50% below the value measured prior to the first incision) correctly predicted the success of the operation in 91% of the subjects. The success rate was correctly predicted as follows: in subgroups of patients with MEN-1 syndrome, 85%, patients after exclusion of MEN-1, 94%, and patients in whom a solitary adenoma was likely after preoperative localization studies, 97%. In 13% of the total number of operations, PTH-measurements led to further exploration, removal of additional parathyroid tissue and normocalcemia postoperatively. In patients without MEN-1 syndrome, in whom a solitary adenoma was likely on the basis of preoperative investigations, it was possible to limit the operation to a unilateral procedure in 87%. CONCLUSION: In the majority of patients with primary hyperparathyroidism, intraoperative PTH-measurement in combination with preoperative imaging studies leads to patients being cured with a unilateral instead of a bilateral operation.

Impaired Sertoli cell function in males diagnosed with Noonan syndrome.

In order to study male gonadal function in Noonan syndrome, clinical and laboratory data, including inhibin B, were gathered in nine pubertal males diagnosed with Noonan syndrome. Bilateral testicular maldescent was observed in four, and unilateral cryptorchidism occurred in two. Puberty was delayed in three patients. Luteinising hormone (LH) levels were normal in all patients in our series, while follicle stimulating hormone (FSH) levels were raised in seven. Inhibin B was low in six males and just above the lower limit of normal in two. Importantly, all three men with normal testicular descent displayed signs of Sertoli cell dysfunction, indicating, in contrast to earlier reports, that bilateral cryptorchidism does not seem to be the main contributing factor to impairment of testicular function in Noonan syndrome. These findings suggest different mechanisms of disturbance in male gonadal function, which is frequently associated with Sertoli dysfunction.

Early identification of persistent trophoblastic disease with serum hCG concentration ratios.

The objective of the present study was to assess the diagnostic potential of serum human chorionic gonadotropin (hCG) ratios obtained at different intervals after evacuation of hydatidiform mole to diagnose persistent trophoblastic disease (PTD) and to compare its diagnostic accuracy with the current FIGO 2000 criteria as a gold standard. We calculated hCG ratios from serum hCG concentrations of 204 patients (86 with and 118 without PTD) registered with the Dutch Central Registry for Hydatidiform Moles between 1977-2004. The hCG ratios obtained in week 1, 3, and 5 after evacuation identified, respectively, 20%, 52%, and 79% of patients with PTD (median: 3.0 weeks) at the 95% specificity level, while FIGO 2000 criteria identified, respectively, 0%, 16%, and 66% (median: 4.7 weeks). It is concluded that a serum hCG ratio identifies patients with PTD approximately 2 weeks earlier than the internationally accepted FIGO 2000 criteria and identifies more than 75% of patients who develop PTD by the fifth week after evacuation.

Identification and characterization of multiple species of tenascin-X in human serum.

We analysed the diversity of tenascin-X (TNX) species in serum and studied parameters that could affect determination of TNX levels in serum. Using western blot analysis we identified at least seven distinct TNX species, ranging from 75 kDa to the presumably full-length 450 kDa form. Purification of serum TNX followed by sequence analysis positively identified two major TNX species of 75 and 140 kDa. We found that serum TNX binds to tropoelastin but not to fibrillar collagens. We conclude that serum TNX is composed of distinct molecular species that retain functional activity.

Is supine rest necessary before blood sampling for plasma metanephrines?

BACKGROUND: The impact of blood sampling in sitting vs supine positions on measurements of plasma metanephrines for diagnosis of pheochromocytoma is unknown. METHODS: We compared plasma concentrations of free metanephrines in samples from patients with primary hypertension obtained after supine rest with those obtained in the sitting position without preceding rest. We also assessed the effects on diagnostic test performance retrospectively in patients with and without pheochromocytoma, and we calculated cost-effectiveness for pheochromocytoma testing. RESULTS: Upper reference limits of plasma free metanephrines were higher in samples obtained from seated patients without preceding rest than from supine patients with preceding rest. Application of these higher upper reference limits to samples from supine patients with pheochromocytoma decreased the diagnostic sensitivity from 99% to 96%. In patients without pheochromocytoma, adjusting the plasma concentration for the effects of sitting while preserving the 99% sensitivity by use of the supine upper reference limits increased the number of false-positive test results from 9% to 25%. CONCLUSIONS: To preserve high diagnostic sensitivity we recommend the use of upper reference limits determined from blood samples collected in the supine position. Under these conditions, negative test results for blood samples obtained with patients sitting are as effective for ruling out pheochromocytoma as negative results from samples obtained after supine rest. Repeat testing with samples obtained in the supine position offers a cost-effective approach for dealing with the increased numbers of false-positive results expected after initial sampling in the sitting position.

A patient with recurrent hypercortisolism after removal of an ACTH-secreting pituitary adenoma due to an adrenal macronodule.

A 41-yr-old female was referred for signs and symptoms of Cushing's syndrome. Cortisol was not suppressed by 1 mg dexamethasone (0.41 micromol/l). Midnight cortisol and ACTH were 0.44 micromol/l and 18 pmol/l, respectively. Urinary cortisol excretion was 250 nmol/24 h (normal between 30 and 150 nmol/24 h). A magnetic resonance imaging (MRI) revealed a pituitary lesion of 7 mm. ACTH and cortisol levels were unaltered by administration of human CRH and high-dose dexamethasone. Inferior sinus petrosus sampling showed CRH-stimulated ACTH levels of 128.4 (left sinus) vs a peripheral level of 19.2 pmol/l, indicating Cushing's disease. After 4 months of pre-treatment with metyrapone and dexamethasone, endoscopic transsphenoidal resection of an ACTH-positive pituitary adenoma was performed. ACTH levels decreased to 2.6 pmol/l and fasting cortisol was 0.35 micromol/l. Despite clinical regression of Cushing's syndrome and normalization of urinary cortisol, cortisol was not suppressed by 1 mg dexamethasone (0.30 micromol/l). Ten months post-operatively, signs and symptoms of Cushing's syndrome reoccurred. A high dose dexamethasone test according to Liddle resulted in undetectable ACTH, but no suppression of cortisol levels, pointing towards adrenal-dependent Cushing's syndrome. Computed tomography (CT)-scanning showed a left-sided adrenal macronodule. Laparoscopic left adrenalectomy revealed a cortical macronodule (3.5 cm) surrounded by micronodular hyperplasia. Fasting cortisol had decreased to 0.02 micromol/l. Glucocorticoid suppletion was started and tapered over 12 months. Symptoms and signs of hypercortisolism gradually disappeared. This case illustrates, that longstanding ACTH stimulation by a pituitary adenoma can induce unilateral macronodular adrenal hyperplasia with autonomous cortisol production.

Forearm vasoconstrictor response in uncomplicated type 1 diabetes mellitus.

BACKGROUND: According to the 'haemodynamic hypothesis', increased tissue perfusion predisposes to microangiopathy in diabetic patients. We hypothesized that the typical haemodynamic changes underlying the increased tissue perfusion can be explained by a decreased sympathetic nerve activity caused by chronic hyperglycaemia. In this study we investigated sympathetic activity in patients with uncomplicated type 1 diabetes mellitus (DM). MATERIALS AND METHODS: In 15 DM patients (DM duration 6.3 +/- 3.8 year; HbA1c 7.9 +/- 1.3%) and 16 age- and sex-matched healthy volunteers (Control), sympathetic nervous system activity was measured at rest (baseline) and during sympathoneural stimulation (lower body negative pressure (LBNP)) by means of interstitial and plasma noradrenaline (NA) sampling and power spectral analysis. Muscle sympathetic nerve activity (MSNA) was measured before (baseline) and during a cold pressure test. Forearm blood flow was measured during forearm vascular alpha- and beta-adrenergic receptor blockade. RESULTS: At baseline, forearm vascular resistance (FVR), plasma NA concentrations, MSNA and heart rate variability were similar in both groups. LBNP-induced vasoconstriction was significantly attenuated in the DM group compared with the Control group (DeltaFVR: 12 +/- 4 vs. 19 +/- 3 arbitrary units, P < 0.05). The responses of plasma NA and heart rate variability did not differ. CONCLUSIONS: Baseline FVR and sympathetic nerve activity are normal in patients with uncomplicated type 1 diabetes. However, the forearm vasoconstrictor response to sympathetic stimulation is attenuated, which cannot be attributed to an impaired sympathetic responsiveness.