Bone metabolism in patients with primary hyperparathyroidism before and after surgery

Primary hyperparathyroidism (PHPT) is accompanied with a reduced bone mineral density (BMD) and an increased risk of fracture. Surgery is the only option for cure. It is hypothesized that in patients with PHPT bone metabolism normalizes after parathyroidectomy (PTX) and that BMD gradually increases. Fifty-two patients with PHPT who underwent surgery were prospectively followed for 1 year. Biochemical analyses were performed at baseline and 1, 4, 7 days; 6 weeks; and 3, 6, and 12 months, and BMD before and one year after surgery. Parathyroid hormone (PTH), calcium, and the bone resorption marker dropped immediately, but transiently after PTX, bone formation decreased more slowly. Osteoprotegerin (OPG) as well as cathepsin K did not show significant changes. BMD of the lumbar spine, but not of the femoral neck, increased significantly within one year after surgery. Moderate correlations existed between the changes of total calcium, ionized calcium, as well as bone-specific alkaline phosphatase and changes of the lumbar BMD. Patients who needed postoperative supplementation with calcium and vitamin D had significantly higher PTH levels. Some gender-specific differences in patients with PHPT were observed. In patients with PHPT, males appear to be more severely affected than females. Within the first year after PTX, bone metabolism normalized, and BMD of the lumbar spine increased. Patients who needed a supplementation with calcium and vitamin D after PTX preoperatively had higher serum levels of PTH.

Persistent arterial stiffness and endothelial dysfunction following successful pancreas-kidney transplantation in Type 1 diabetes

OBJECTIVE

Successful simultaneous pancreas-kidney transplantation (SPK) in Type 1 diabetic (T1DM) patients results in improved cardiovascular outcome and survival. However, it is doubtful whether the impairment of cardiovascular and endothelial function in T1DM can be completely reversed.

METHODS

Pulse-wave velocity, stroke volume, heart rate, serological markers of endothelial dysfunction (soluble intercellular, vascular cell-adhesion molecules, E-selectin, and plasminogen-activator-inhibitor-1) were measured in 10 T1DM patients after SPK with non-diabetic glucose levels, 10 T1DM patients with poor [T1DM>8; glycated haemoglobin (HbA1c)>8%], and 10 with good glucose control (T1DM<7, HbA1c<7%), in 6 non-diabetic patients after kidney transplantation (KT) and 9 non-diabetic control subjects (CON), matching for major anthropometric characteristics.

RESULTS

Pulse-wave velocity was increased in SPK (P < 0.02 vs. CON, KT, T1DM<7) and in T1DM>8 (P < 0.02 vs. T1DM<7). Systolic blood pressure was increased in SPK (P < 0.05 vs. CON). Stroke volume was reduced in SPK, T1DM>8 and T1DM<7 and KT (P < 0.01 vs. CON). Heart rate was elevated in SPK and in T1DM>8 (P < 0.0003 vs. CON and T1DM<7). In SPK, soluble intercellular and vascular cell-adhesion molecules were 100% and 44% higher (P < 0.03 vs. CON), respectively, while plasminogen-activator-inhibitor-1 was decreased in SPK (P < 0.02 vs. CON).

CONCLUSION

T1DM patients after SPK experience arterial stiffness, a higher heart-rate and blood pressure, reduced stroke volume and serological signs of endothelial dysfunction. Thus, functional and structural cardiovascular alterations as a result of glucotoxicity, uraemia and hypertension in T1DM might not be completely resolved by SPK.

The bone marker plot: an innovative method to assess bone turnover in women

BACKGROUND

Biochemical markers of bone turnover reflect the resorptive and reconstructive effects that act on the skeleton. Although elevated markers are commonly interpreted as a sign of an increased turnover rate, the balance between bone resorption and formation is mostly neglected. We introduce a graphic report combining both complementary processes.

MATERIALS AND METHODS

Bone turnover markers were measured in 599 women (aged 25-74 years). To set up reference ranges, 269 from 599 women were selected because of having T-scores > -1 and inconspicuous basic laboratory data. Concentrations of resorption and formation markers were mathematically transformed to build up plots with four fields, symbolizing fast and slow resorption and fast and slow formation processes. The reference data of bone turnover were represented by a 95% confidence ellipse. For individual marker plots, we converted data of bone turnover markers from therapy follow-up profiles of patients in a similar manner.

RESULTS

In pre-, peri- and postmenopausal women (n= 190, 39 +/- 6 years; n= 35, 51 +/- 6 years; n= 44, 55 +/- 5 years, respectively), the medians of the bone resorption marker CrossLaps and of the bone formation markers osteocalcin and aminoterminal propeptide of type I procollagen were 0.13/0.16/0.22 ng mL(-1), 21/21/25 ng mL(-1) and 36/35/45 ng mL(-1), respectively. In postmenopausal women, the marker plots revealed a shift towards accelerated bone resorption. A discrimination from osteopenic women (n= 138) failed.

CONCLUSION

The proposed marker plot facilitates the intuitive perception of bone turnover in individual patients as well as in patient groups by a synopsis of the balance between bone formation and resorption with the rate of these processes.

Sporadic hypercalcitoninemia: clinical and therapeutic consequences

'Calcitonin screening' is not accepted as the standard of care in daily practice. The clinical and surgical consequences of 'calcitonin screening' in a series of patients with mildly elevated basal calcitonin and pentagastrin stimulated calcitonin levels are presented. 260 patients with elevated basal (>10 pg/ml) and stimulated calcitonin levels (>100 pg/ml) were enrolled in this prospective study. None of the patients was member of a known medullary thyroid carcinoma family. Thyroidectomy and bilateral central and lateral neck dissections were performed. Testing for the presence of germ-line mutations was performed in all patients. Histological and immunohistochemical findings were compared with basal and stimulated calcitonin levels. All patients were subsequently followed biochemically. C-cell hyperplasia (CCH) was found in 126 (49%) and medullary thyroid cancer was found in 134 (51%) patients. RET proto-oncogen mutations were documented in 22 (8%) patients (medullary thyroid cancer:18, CCH:4). In 56 (46%) of 122 patients, sporadic CCH was classified neoplastic ('carcinoma in situ'). Of 97 (72%; 10 with hereditary medullary thyroid cancer) had pT1 (International Union against Cancer recommendations 2002) and 33 (25%) had pT2 or pT3 and 4 (3%) pT4 tumors. Of 39 (29.1%) had lymph node metastases. 106 (79.1%; 15 (38.5%) with lymph node metastases) patients were cured. Evaluation of basal and stimulated calcitonin levels enables the prediction of medullary thyroid cancer. All patients with basal calcitonin >64 pg/ml and stimulated calcitonin >560 pg/ml have medullary thyroid cancer. Medullary thyroid cancer was documented in 20% of patients with basal calcitonin >10 pg/ml but <64 pg/ml and stimulated calcitonin >100 pg/ml but <560 pg/ml.

Pulmonary and systemic effects of inhaled PACAP38 in healthy male subjects

BACKGROUND

Pituitary adenylate cyclase activating polypeptide 1-38 (PACAP38) displays biological activities (e.g. bronchodilatory, pulmonary vasodilatory and anti-inflammatory properties) that are relevant in several pulmonary diseases. The aim of this study was to assess the safety and tolerability and the pulmonary and systemic effects of inhaled PACAP38 in humans.

MATERIALS AND METHODS

Twelve healthy male subjects (mean age 28) were studied in a randomized, double-blind, placebo-controlled dose escalation trial with inhalation of PACAP38 to a cumulative dose of 480 microg. Lung function was measured by body plethysmography. Systemic absorption was evaluated by plasma levels, skin blood flux (estimated by laser Doppler imager fluxmetry) and systemic haemodynamics.

RESULTS

Inhalation of PACAP38 did not cause relevant adverse reactions or an increase of PACAP38 plasma levels. No statistically significant changes in lung function tests and no systemic effects (blood pressure, pulse rate or skin blood flux) occurred.

CONCLUSION

Inhaled PACAP38 was well tolerated without systemic side-effects in healthy male subjects.

No effect of homocysteine-lowering therapy on vascular inflammation and haemostasis in peripheral arterial occlusive disease

BACKGROUND

Although peripheral arterial occlusive disease (PAOD) is significantly associated with elevated homocysteine levels, the clinical relevance of hyperhomocysteinaemia for the prevention and progression of PAOD is still unknown.

MATERIALS AND METHODS

A total of 65 patients suffering from symptomatic PAOD with elevated homocysteine levels were randomized onto placebo or B-vitamins (50 mg thiaminhydrochlorid, 50 mg pyridoxine, and 0.05 mg cyanocobalamin), plus 5 mg folic acid daily for 6 weeks. Serum levels of folic acid, vitamin B12, creatinine, ultra-sensitive C-reactive protein (usCRP), interleukin (IL)-6, IL-8, IL-18, monocyte-chemo-attractant-protein-1 (MCP-1) and plasma levels of homocysteine, tissue factor (TF) and tissue factor pathway inhibitor (TFPI) were determined on the 1st day and 42nd day. Primary outcome was reduction of homocysteine, secondary outcomes were reduction of usCRP, IL-6, IL-8, Il-18, MCP-1, TF and TFPI.

RESULTS

The mean reduction of homocysteine concentration was 33% (95%CI 33.36-55.76, or 18.9+/-5.4 micromol L-1-12.6+/-2.8 micromol L-1, P=0) in the B-vitamin group compared with 1% in the placebo group. Folic acid (P=0) and vitamin B12 (P=0) increased significantly in the verum group, but both remained unchanged in the control group. No treatment effect of lowering of homocysteine on any markers of haemostasis (TF, TFPI) or inflammation (usCRP, IL-6, IL-8, IL-18 and MCP-1) was observed.

CONCLUSION

Although homocysteine is associated with vascular disease risk in the general population and in particular with PAOD, marked lowering of homocysteine concentrations by folic acid and B-vitamin supplementation does not influence inflammatory responses involving usCRP, IL-6, IL-8, IL-18 and MCP-1, nor tissue factor. These results provide evidence against a major effect of hyperhomocysteinaemia on vascular chronic inflammation or coagulation in patients with symptomatic peripheral arterial occlusive disease.

Mode of delivery is associated with maternal and fetal endocrine stress response

OBJECTIVE

To determine whether mode of delivery is associated with the endocrine stress response in mother and child.

DESIGN

Prospective observational study.

SETTING

Tertiary care centre, University hospital.

POPULATION

A total of 103 nulliparous women with uncomplicated singleton pregnancies at term undergoing either spontaneous labour for vaginal delivery or delivering by caesarean section without labour. Thirty women delivered vaginally without any pain relief, 21 women delivered vaginally with epidural anaesthesia, 23 women had ventouse extraction and 29 women underwent caesarean section with epidural analgesia.

METHODS

After delivery, maternal and umbilical cord blood was collected for determination of different stress-associated hormones.

MAIN OUTCOME MEASURES

Concentrations of epinephrine (EP), norepinephrine (NOR), adrenocorticotropic hormone (ACTH), cortisol (CORT), prolactin (PRL), corticotropin-releasing factor and beta-endorphin (BE).

RESULTS

Caesarean section was associated with significantly lower maternal concentrations of EP, NOR, ACTH, CORT, PRL and BE and lower newborn levels of EP, NOR and CORT compared with all other modes of delivery. Concentrations of EP, ACTH and BE differed significantly in newborns delivered by normal vaginal delivery, vaginal delivery with epidural anaesthesia and ventouse extraction.

CONCLUSIONS

The mode of delivery and analgesia used during birth are associated with maternal and fetal endocrine stress responses.

Early diagnosis and curative therapy of medullary thyroid carcinoma by routine measurement of serum calcitonin in patients with thyroid disorders

To identify patients with medullary thyroid carcinoma (MTC) at a potentially curable stage of the disease, serum concentrations of calcitonin (hCT) were determined in 14,000 patients (including 10,158 patients with thyroid nodules) referred to a thyroid outpatient clinic. Excluding patients in whom elevated basal hCT concentrations had already been known at the time of their referral, 507 patients with thyroid nodules presented basal concentrations of hCT of more than 10 pg/ml. Following stimulation by IV pentagastrin (0.5 microg/kg BW), hCT concentrations of more than 100 pg/ml were seen in 103 patients. This group included 32 new cases of MTC (29 patients with sporadic MTC and 3 new index cases of the familial form) and 43 patients with C cell hyperplasia (CCH). Among the 3,843 patients without thyroid nodules, 2 were found to harbor sporadic MTC while 4 had CCH. As compared to 1.1 cases of MTC per 1,000 patients with nodular thyroid diseases diagnosed in our institution before hCT screening was begun, 3.2 cases of MTC per 1,000 patients were identified when hCT was determined in all patients with thyroid nodules. The determination of hCT in all patients with thyroid nodular disease facilitates the timely diagnosis of MTC, thus providing the chance of curative surgery.

Primary hyperparathyroidism as the leading symptom in a patient with a Y791F RET mutation

Primary hyperparathyroidism (PHP; serum calcium 2.75 mmol/L, PTH 226 pg/ml) had been the first clinical manifestation of MEN-2A in a female patient (aged 55 years) with a mutation (Y791F, TAT-->TTT) in exon 13 of the RET proto-oncogene. The patient has a pentagastrin-induced rise in serum calcitonin (up to 57 pg/ml) considered normal for noncarriers but abnormal in family members of MEN-2 patients. This is the first case of MEN-2 due to this specific mutation with primary hyperparathyroidism as the first manifestation of the disease. In addition, the patient harbored, within the Menin gene, a polymorphism (D418D) reportedly associated with sporadic primary hyperparathyroidism. This case report indicates that molecular biological tests in MEN- 2 may only suggest a certain phenotype but cannot predict it with certainty. It may also suggest that genetic screening for MEN-2 may be advisable in patients with primary hyperparathyroidism and a borderline-high pentagastrin stimulation test, even in the absence of a positive family history.

Hormonal profile and fertility in patients with Anderson-Fabry disease

Anderson-Fabry disease is a glycosphingolipid storage disorder with an X-linked recessive inheritance. The alpha-galactosidase A deficiency leads to a progressive accumulation of globotriaosylceramide in the endothelium and tissue cells of various organs. The kidney, heart and brain are predominantly affected. Reports on endocrine function and fertility rates in patients with Anderson-Fabry disease are sparse. In the present study, we assessed ovarian, testicular and adrenal function in a cohort of patients with Anderson-Fabry disease. Plasma follicle-stimulating hormone, luteinizing hormone, prolactin, estradiol, testosterone, sex hormone-binding globulin, somatotropin, insulin-like growth factor-I and serum cortisol were measured in 13 patients (six female and seven male), currently observed in an outpatient clinic. The profile revealed an undisturbed hormonal function and a normal fertility rate in both male and female Anderson-Fabry patients when compared with the corresponding Austrian population.

Effect of systemic vitamin C on free fatty acid-induced lipid peroxidation

OBJECTIVES

Plasma malondialdehyde (MDA), a reactive product of lipid peroxidation, may be influenced by anti-oxidant therapy. The aim of the present study was to investigate if elevated MDA as induced by increased free fatty acids (FFA) correlates with endothelial function and is affected by high doses of vitamin C.

METHODS

The study design was randomised, placebo-controlled, double blind, 2-way cross over. Plasma MDA concentrations and forearm blood flow (FBF) responses to intra-arterial acetylcholine (ACh) and glyceryl trinitrate were assessed during co-administration of vitamin C or placebo in the presence of increased plasma FFA by Intralipid/heparin infusion in 10 healthy male subjects.

RESULTS

The seven-fold rise in plasma FFA was associated with an increase in plasma MDA concentrations (r=0.7, p<0.001) and decreased FBF responses to ACh (r=-0.4, p<0.01). Co-administration of vitamin C restored the impaired reactivity of FBF to ACh but had no effect on elevated MDA concentrations.

CONCLUSIONS

Anti-oxidant vitamin C improves lipid-induced impairment of endothelium-dependent vasodilation, but does not alter MDA formation or breakdown.

Effects of parathyroidectomy on lead mobilization from bone in patients with primary hyperparathyroidism

Since lead (Pb) accrued from environmental exposure accumulates in bone with a half life time between 6 and 10 years, a release of bone Pb into the circulation and/or urine (PbU) should be expected in diseases with increased bone metabolism such as hyperparathyroidism. We studied 60 patients with primary hyperparathyroidism (pHPT, 50 women, 10 men, aged 61.4 +/- 10.6 and 64.1 +/- 9.9 years, respectively) (a) before, (b) 1-6 months, and (c) 6-12 months after parathyroidectomy. Besides lead in blood (PbB) and lead in 24-h urine samples (PbU), parathyroid hormone (PTH), serum Ca2+, osteocalcin (OC), phosphate (PO4), and serum pyridinoline cross-linked telopeptide (cTP) were determined. Control data were determined in 20 healthy age-matched subjects. As expected, Ca2+ decreased after parathyroidectomy. Mean PbB in patients with pHPT was in the same range as in controls. A decrease of PbB after parathyroidectomy was found in the interval beyond 6 months. In contrast, mean PbU initially increased after surgery (3.05 +/- 1.94 vs. 4.25 +/- 2.65 microg/l, P = 0.004) and was not different beyond 6 months in comparison with preoperative values at (c). Investigating only patients with PTH < 150 ng/l, no significant PbB or PbU alterations were detected before and after parathyroidectomy. In patients with PTH > 150 ng/l, the decrease of PbB at (c) was more pronounced as was the increase of PbU at (b). In these patients, PbB and OC as well as PbB and cTP were correlated preoperatively. In conclusion, our data show that in environmentally lead-exposed (by food or by pollution) hyperparathyroid individuals, there is no hazardous PbB release from bone. The preoperative correlation between PbB and OC in pHPT patients with PTH > 150 ng/l provides evidence that in fact there is a Pb release from bone into the blood-pool by bone remodeling. The increase of PbU after parathyroidectomy is suspected to be caused by PTH-dependent Pb accumulation in the kidney, which seems to be restored with decreasing PTH. Moreover, our data confirm prior findings that bone remodeling seems to be normalized 6 months after parathyroidectomy.

Bone metabolism in patients more than five years after bone marrow transplantation

We investigated the bone metabolism of 22 patients (median age 38 years) over 6 years after allogeneic bone marrow transplantation (BMT). Biplanar roentgenograms of the thoracic and lumbar spine were used to diagnose vertebral deformities caused by fractures. The actual bone mineral density (BMD) of the lumbar spine and the femoral neck were measured. Laboratory tests included calcium, phosphate, parathyroid hormone, a marker of bone resorption (beta-crosslaps, CTX), markers of bone formation (osteocalcin, bone-specific alkaline phosphatase), osteoprotegerin (OPG)--antagonist of the osteoclast differentiation factor RANKL, and sex hormone status. One patient had a vertebral fracture. Seven patients (28%) had osteopenia in the lumbar spine while 12 patients (48%) had osteopenia in the femoral neck. Bone resorption was increased in nine patients (43%) and bone formation was increased in four patients (20%). BMT recipients had significantly increased serum levels of OPG (P=0.029). Three women (75%) and four men (25%) were hypogonadal. The data showed that BMD is reduced and bone metabolism is still disturbed more than 6 years after BMT. The RANKL/osteoprotegerin system appears to play an important role in the pathophysiology of late post transplantation osteoporosis.

Frequency of RET proto-oncogene mutations in patients with normal and with moderately elevated pentagastrin-stimulated serum concentrations of calcitonin

The possibility of germline mutations of the RET proto-oncogene (exons 10, 11, 13, 14, and 16) was investigated in 75 patients (57 men, 18 women) with a negative family history for medullary thyroid carcinoma (MTC), elevated (> 10 pg/mL) basal serum concentrations of human calcitonin (hCT) and a pentagastrin (PG)-stimulated serum hCT ranging from 50-100 pg/mL. Seventy patients (50 men, 20 women) with basal serum calcitonin concentrations in the normal range served as controls. Among the 75 patients with elevated basal serum hCT concentrations we identified 1 man with the mutation S649L and 2 patients (1 man and 1 woman) with the mutation Y791F. Among the 70 individuals with normal basal calcitonin 1 man and 1 woman presented with the mutation Y791F. No other mutations (such as those in codons 618 or 634, considered to be of greater clinical relevance) were identified in either group. On the other hand, the RET proto-oncogene mutation Y791F, characterized by a low penetrance, occurs comparatively frequently among patients with normal serum calcitonin concentrations. To preselect patients for RET screening by moderately (50-100 pg/mL) pentagastrin stimulation hCT concentrations does not increase the number of identified cases of familial MTC.

The role of intraoperative quick PTH measurements in primary hyperparathyroidism

BACKGROUND

In patients with primary hyperparathyroidism (PHPT), circulating concentrations of intact parathyroid hormone (PTH), decline dramatically within minutes following surgical excision of hyperfunctioning parathyroid tissue. The magnitude of this decay correlates with the completeness of resection of hyperfunctioning parathyroid tissue and can be monitored during the operation.

METHOD

Intraoperative Quick PTH (QPTH) monitoring and pitfalls of more than 350 patients, who were operated because of primary hyperparathyroidism are analyzed. Special attention is given to correct baseline values and interpretation of QPTH values.

RESULTS

QPTH monitoring is able to distinguish reliably between single and multiple gland disease and is an indispensable prerequisite for any form of limited parathyroid exploration. Experience with QPTH monitoring is necessary to achieve the excellent results known from bilateral neck exploration.

CONCLUSION

Applying correct baseline values and cautious interpretation of QPTH values results in excellent results. Nevertheless more data must be collected to allow reliable interpretation of QPTH monitoring in all patients with PHPT.

Serum concentrations of dehydroepiandrosterone sulfate and leptin in obese patients with normal serum cholesterol

Normal (< 200 mg/dL) serum concentrations of cholesterol and a favorable ratio of cholesterol/high-density lipoprotein (HDL)-cholesterol are frequently seen in morbidly obese (body mass index [BMI] > 35 kg/m2) patients. Because it is unknown whether this subgroup is characterized by differences in other potential markers of cardiovascular disease, serum concentrations of dehydroepiandrosterone sulfate (DHEAS) and leptin were determined in 155 obese patients (BMI > 35 kg/m2, aged 20 to 50 years) with normal (n = 72) or with elevated (n = 83) total serum cholesterol. We found that seemingly negative marginal correlations between serum concentrations of DHEAS and cholesterol, as well as between DHEAS and the ratio cholesterol/HDL-cholesterol, were not any more apparent after correction for age, sex, and BMI. A negative correlation between serum leptin concentrations and the ratio cholesterol/HDL-cholesterol persisted after correction for age, sex, and BMI. In morbid obesity, there appears to be an association between serum concentrations of leptin and a more favorable lipid profile, whereas there is no direct interrelation between serum concentrations of cholesterol and DHEAS.

Transcapillary insulin transfer in human skeletal muscle

BACKGROUND

Transcapillary insulin transfer is considered a rate-limiting step in insulin action at supraphysiological insulin concentrations. However, it remains unclear whether this concept also applies for physiological conditions.

MATERIALS AND METHODS

In the present study we set out to characterize transcapillary insulin transfer by measuring insulin concentrations in plasma and interstitial space fluid of skeletal muscle during an oral glucose tolerance test and euglycaemic hyperinsulinaemic clamp conditions, respectively. For this purpose we employed in vivo microdialysis of skeletal muscle in conjunction with an ultrasensitive insulin assay in eight healthy lean male volunteers (aged 25 +/- 1 years).

RESULTS

Insulin concentrations at baseline were 48 +/- 8 pmol x L(-1) in plasma and 19 +/- 4 pmol x L(-1) in the interstitium (P = 0.002). The mean interstitium to plasma ratio at baseline was 0.48 +/- 0.09 pmol x L(-1). During the oral glucose tolerance test the interstitium to plasma ratio remained unchanged (0.43 +/- 0.12, P = NS vs. baseline), but was significantly reduced during euglycaemic hyperinsulinaemic clamp conditions at steady-state hyperinsulinaemia (0.12 +/- 0.01, P = 0.01 vs. baseline).

CONCLUSION

In summary there is a substantial transcapillary insulin gradient in healthy human skeletal muscle under baseline and glucose-stimulated conditions. Our findings support the hypothesis of a saturable transcapillary insulin transport representing a partly rate-limiting step for insulin action.

Homocysteine levels in patients with Raynaud's phenomenon

BACKGROUND

Patients with Raynaud's phenomenon (RP) have vasomotor dysregulation, mainly cause by dysfunction of the endothelium. Since homocysteine has been found to be damaging to endothelial cells, we investigated the concentrations of plasma homocysteine, folate and vitamin B12 in patients with primary or secondary RP compared to healthy individuals.

PATIENTS AND METHODS

We measured the concentrations of plasma fasting homocysteine, folate and vitamin B12 in a group of healthy individuals (n = 45) and in patients with primary (n = 26) or secondary RP (n = 42).

RESULTS

Median homocysteine levels in healthy controls and in patients with primary RP, secondary RP were 7.9 (IQR 4.1 to 11.8) 9.8 (IQR 5.1 to 14.4), and 10.6 (6.0 to 15.3) mumol/L, respectively. Patients with primary and secondary RP had significantly higher homocysteine concentration compared to healthy controls (Kruskal Wallis p = 0.01). After matching for age and sex, patients with either primary or secondary RP showed significantly higher homocysteine levels (Wilcoxon p < 0.0001). No significant differences between the three groups were found concerning serum levels of vitamin B12 (p = 0.9) and serum folate levels (p = 0.2).

CONCLUSION

These data demonstrate that patients with RP have higher plasma levels of homocysteine. No significant differences in folate and vitamin B12 levels were found between patients with primary RP, secondary RP, and healthy individuals. These data suggest that homocysteine may play a role in RP and may provide new clues in understanding of the vasomotor dysregulation.

Molecular and clinical characterisation of homocystinuria in two Austrian families with cystathionine beta-synthase deficiency

The influence of the genotype on the phenotypic expression of homocystinuria due to cystathionine beta-synthase (CBS) deficiency is frequently unclear. We therefore investigated the genotype and the phenotype of CBS deficiency in two Austrian families also considering genetic polymorphisms with a putative association with vascular disease (MTHFR 677C-->T, MTHFR 1298A-->C, F5 1691G-->A, F2 20210G-->A) and response to therapy. We identified the CBS 833T-->C/1058C-->T and CBS 828ins104/1358del134 compound heterozygous genotype in our index patients. Both patients showed mental retardation and ectopia lentis. CBS 833T-->C/1058C-->T was associated with severe vascular complications, which was not the case for CBS 828ins104/1358del134. The patient with CBS 828ins104/1358del134 was negative for F5 1691G-->A, F2 20210G-->A, MTHFR 677C-->T, and MTHFR 1298A-->C, while the patient with CBS 833T-->C/1058C-->T was heterozygous for MTHFR 1298A-->C. A combination therapy including pyridoxine, folic acid, hydroxycobalamin, and betaine failed to lower total homocysteine plasma levels below 50 mumol/L in both patients. In summary, our study demonstrates that the CBS 833C/1058T-MTHFR 1298AC genotype can be related to severe vascular disease, while the CBS 828ins104/1358del134-MTHFR 1298AA genotype presents with a somewhat milder clinical phenotype. Both genotypes do not allow for normalisation of total homocysteine plasma levels following vitamin therapy.

The use of the pyridostigmine growth hormone-releasing hormone stimulation test to detect growth hormone deficiency in patients with pituitary adenomas

The pyridostigmine (PD)/growth hormone-releasing hormone (GHRH) stimulation test was used to determine growth hormone (GH) secretion in patients with pituitary adenomas prior to (n = 55) and after (n = 72) transsphenoidal adenomectomy, as well as in 98 controls. In controls, maximum concentrations of GH showed a strong negative relationship both with body mass index (BMI) and age. Having calculated the 95% confidence intervals for maximum GH concentrations to be expected for any given age and BMI according to a statistical model, we compared these individually predicted ranges to GH concentrations actually observed in patients with pituitary disease during PD/GHRH stimulation. Preoperatively and postoperatively, a maximum GH concentration below the calculated confidence intervals was seen in 29 of 55 (52%) and in 57 of 72 (79%) of these patients, respectively. In the remaining patients, maximum GH concentrations were in or above the range defined by these confidence intervals. Our results indicate that maximum concentrations of GH during the PD/GHRH test depend to a large extent on the individuals' age and BMI. The results obtained with the PD/GHRH stimulation must, in each individual patient, be compared with a large control group taking into account both age and BMI. In individuals older then 55 years and with a BMI greater than 35 kg/(2), the diagnosis of GH deficiency cannot safely be made, at least not with this test.

The effect of calisthenic home exercises on postmenopausal fractures--a long-term observational study

OBJECTIVES

To evaluate the long-term effects of calisthenic home exercises on the incidence of fractures in postmenopausal women.

DESIGN

Controlled long-term observational study.

METHODS

Postmenopausal women between 45 and 75 years of age who had been randomly assigned to an exercise or control group in the course of a previous study conducted 5-10 years ago, were invited for follow-up. The number of fractures before and during the observation time were recorded by means of a questionnaire. Vertebral deformities due to fractures were diagnosed by X-rays at entry and at follow-up. Walking speed, muscle strength, static posturography, and maximum oxygen uptake were measured in addition.

RESULTS

After an average follow-up time of 7.6+/-1.1 years, 73 women of the exercise group and 64 subjects of the control group were investigated. Thirty-three per cent (n=24) of the exercise group reported to have exercised continuously at least three times a week for 20 min. No intergroup differences between the compliant and non-compliant exercisers and the control group were seen in the number of fractures. However, the incidence of fracture was lowest in women with a baseline bone mass less than one standard deviation (SD) below the mean for young adults (high BMC) and highest in those with more than 2.5 SD below the mean for young adults (low BMC) (P<0.001, odds ratio 2.9 [95% CI, 1.59-5.39]).

CONCLUSION

This long-term follow-up did not produce any evidence that prescription of a calisthenic home exercise program may prevent fractures in postmenopausal women aged between 61+/-6.4 and 68+/-6.5 years.

Characterization of a vitamin D receptor knockout mouse as a model of colorectal hyperproliferation and DNA damage

The vitamin D receptor knockout (VDR-KO) mouse presents with a skeletal phenotype typical for complete lack of genomic 1,25-dihydroxycholecalciferol effects. Our previous data from human colorectal tissue suggest that the steroid hormone and its receptor may have protective function against tumour progression. In order to investigate the relevance of the vitamin D system for pre-malignant site-directed changes in the colon, we characterized the amount and site-specific distribution of the VDR along the large intestine in wild-type (WT), heterozygote (HT) and KO mice. We also evaluated expression of proliferating cell nuclear antigen (PCNA), of cyclin D1 and the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress. In colon ascendens, proliferative cells were dispersed all along the crypt and expression levels of all three markers were high in WT mice. A decrease of VDR expression did not affect expression significantly. In colon descendens, however, fewer proliferative cells were solely located in the lower third of the crypt, and an inverse relationship between VDR reduction, PCNA positivity and cyclin D1 expression was found in HT and KO mice. In parallel to enhanced proliferation a highly significant increase of 8-OHdG positivity occurred. Therefore, the sigmoid colon of VDR-KO mice, fed on an appropriate lactose/calcium-enriched diet to alleviate impaired calcium homeostasis-related phenotypic changes, is an excellent model for investigating induction and prevention of pre-malignant changes in one of the hotspots for human colorectal cancer incidence.

Minimally invasive open parathyroidectomy in an endemic goiter area: a prospective study

HYPOTHESIS

Single-gland disease identified by preoperative localization studies in combination with rapid intraoperative parathyroid hormone monitoring seems to allow a limited exploration of the neck in sporadic primary hyperparathyroidism. Minimally invasive open parathyroidectomy by lateral approach (oMIP) in sporadic primary hyperparathyroidism seems feasible in an endemic goiter region.

DESIGN

One hundred consecutive patients with sporadic primary hyperparathyroidism underwent preoperative double-phase technetium Tc 99m sestamibi scanning with single-photon emission computed tomography and high-resolution ultrasonography with color Doppler imaging of the cervical region. All patients were operated on with the use of quick parathyroid hormone assay to confirm the surgical success "on-line." Patients with localized single-gland disease, irrespective of additional ipsilateral thyroid disease requiring surgery, were selected for oMIP. Success of the preoperative localization studies, postoperative (at least 6 months) serum calcium levels, and operating time were analyzed.

SETTING

University hospital, section of endocrine surgery.

RESULTS

Of 100 patients, 83 (83%) were considered suitable for oMIP. In 69 patients, oMIP was finished successfully. Nine of these had had previous neck surgery, and another 24 underwent additional ipsilateral thyroid resection. Permanent normocalcemia was achieved in 67 (97.1%) of 69 patients and 98 (98%) of 100 patients.

CONCLUSION

The oMIP in combination with quick parathyroid hormone assay may become the treatment of choice for sporadic primary hyperparathyroidism in an endemic goiter region in centers with high experience in thyroid and parathyroid surgery. It allows treatment of concomitant ipsilateral thyroid disease and is feasible in reoperations.

Markers of bone turnover in postmenopausal women receiving hormone replacement therapy

We investigated the effects of hormone replacement therapy (n = 27) on biochemical markers of bone turnover in a cross-sectional study of 127 postmenopausal women (according to WHO guidelines 18 patients had normal bone mineral density and 109 suffered from bone loss). Urinary excretion of free deoxypyridinoline and C- or N-telopeptide fragments of type I collagen served as bone resorption markers, serum osteocalcin as a bone formation marker. In women with no hormone replacement therapy, only C- and N-telopeptides correlated significantly with the lumbal T-score as an index for bone mineral density. Patients with bone loss receiving hormone replacement therapy exhibited significantly lower C-telopeptide, N-telopeptide and osteocalcin levels than those with no therapy (mean -45%, -43% and -26%, respectively), while deoxypyridinoline showed no significant differences. Among the markers investigated, C- and N-telopeptides seemed to be more reliable to detect therapeutic effects on bone metabolism. We present a preliminary model to evaluate bone turnover and resorption/formation rate.

Efficacy of folinic versus folic acid for the correction of hyperhomocysteinemia in hemodialysis patients

The effectiveness of intravenous folinic acid or intravenous folic acid for the treatment of hyperhomocysteinemia of hemodialysis patients is unknown. In a randomized, controlled, double-blind trial, 66 hemodialysis patients were administered either 15 mg of folic acid or an equimolar amount (16.1 mg) of folinic acid intravenously three times weekly. Normalization of total homocysteine (tHcy) plasma levels after 4 weeks of treatment was achieved in 10 patients (30.3%) in the folic-acid group and 6 patients (18.2%; P: = 0.389) in the folinic-acid group (normalization at any time during the study period in 39.4% and 33.3% of the patients; P: = 0.798). The relative reduction in tHcy plasma levels at week 4 was 32.2% in the folic-acid group and 34.1% in the folinic-acid group. A high baseline tHcy plasma concentration (P: = 0.00001), methylenetetrahydrofolate reductase (MTHFR) 677TT/1298AA genotype (P: = 0.03540), and low red blood cell folate concentrations (P: = 0.02285) were associated with a better relative response to treatment. Normalization of tHcy plasma levels was dependent on a lower baseline tHcy level (P: = 0.01976), younger age (P: = 0.00896), and MTHFR 677TT/1298AA or 677CT/1298AC genotypes (P: = 0.00208 and P: = 0.02320, respectively). A 4-week course of intravenous folinic acid is not superior to intravenous folic acid in reducing elevated tHcy plasma levels in hemodialysis patients. The response to treatment is predicted by tHcy plasma level, red blood cell folate content, and MTHFR genotype.

Increased plasma leptin in gestational diabetes

AIMS/HYPOTHESIS

Insulin resistance as well as marked changes in body weight and energy metabolism are associated with pregnancy. Its impact on plasma leptin is not known and was determined in this longitudinal study in both diabetic and normal pregnancy.

METHODS

At 28 gestational weeks plasma concentrations of leptin and B-cell hormones were measured at fasting and after an oral glucose load (OGTT:75 g) in women with gestational diabetes and pregnant women with normal glucose tolerance and compared with women who were not pregnant (C).

RESULTS

Plasma leptin (ng/ml) was higher (p < 0.001) in women with gestational diabetes (24.9 +/- 1.6) than in women with normal glucose tolerance (18.2 +/- 1.5) and increased in both groups when compared with the non-pregnant women (8.2 +/- 1.3; p < 0.0005). No change in plasma leptin concentrations was induced by OGTT in any group. Basal insulin release was higher (p < 0.05) in women with gestational diabetes compared with the pregnant women with normal glucose tolerance. Marked insulin resistance was confirmed by a 20 % lower (p < 0.05) insulin sensitivity in subgroup analysis and a decrease of almost 40% in fasting glucose/insulin ratio (p < 0.005) in women with gestational diabetes. Leptin correlated in women with gestational diabetes with basal plasma concentrations of glucose (p < 0.02), insulin (p < 0.004) and proinsulin (p < 0.01) as well as with BMI (p < 0.001) and overall pregnancy induced maternal weight gain (p < 0.009). With normalisation of blood glucose 8 weeks after delivery in women with gestational diabetes their plasma leptin decreased (p < 0.0005) to 17.3 +/- 1.9 ng/ml but did not completely normalize (p < 0.05 vs non-pregnant women).

CONCLUSION/INTERPRETATION

Our data show that women with gestational diabetes without any change in plasma leptin upon oral glucose loading have increased plasma leptin concentrations during and after pregnancy, a clear association of plasma leptin with the respective concentration of glucose and insulin resistance as well as with changes in body weight, and a failure to normalize spontaneously BMI to the same extent as pregnant women with normal glucose tolerance when compared with matched control subjects.

Is there a role of cyclosporine A on total homocysteine export from human renal proximal tubular epithelial cells?

BACKGROUND

Immunosuppressive therapy may influence homocysteine metabolism in allograft recipients. We examined whether cyclosporine A influences the in vitro formation of homocysteine as determined by the measurement of total homocysteine (tHcy) concentrations in supernatants of human renal proximal tubule epithelial cells (hRPTEC), an important site of homocysteine metabolism.

METHODS

Cells were incubated with and without vitamins in the presence of low or high methionine concentrations at different cyclosporine A concentrations for 24, 48 and 72 hours (N = 7 for each experiment). The concentration of tHcy in culture supernatants was measured by a fluorescence polarization immunoassay. Data were analyzed by four-way ANOVA, three-way ANOVA and t tests.

RESULTS

The Hcy export from hRPTEC (tHcy in the culture supernatant) was 2.69 micromol/L during standard cell culture conditions at time point 24 hours and increased by 28.3% at 48 hours and by 44.6% at 72 hours. Comparisons of tHcy levels in culture supernatants over time by four way ANOVA showed that cyclosporine A at 200 or 800 ng/mL had no influence on tHcy export from hRPTEC (P = 0.67991). In contrast, the presence of vitamins in the medium (P = 0.000001), in vitro methionine loading (P < 0.000001), and prolonged incubation time (P < 0.000001) were associated with an increase of tHcy export from hRPTEC. Significant interactions in this analysis were "vitamins x methionine" (P = 0.001804), "vitamins x time" (P = 0.001478), "methionine x time" (P < 0.000001), and "vitamins x methionine x time" (P = 0.018128), pointing to a combined effect of vitamins in the presence of high methionine concentrations at the later time points.

CONCLUSION

Our study shows that hRPTEC export Hcy into the cell culture medium, an effect that is enhanced by in vitro methionine loading and modulated by the presence of vitamins. Cyclosporine A had no major influence on Hcy export from tubule cells. Therefore, our findings do not support the assumption that cyclosporine A elevates total homocysteine plasma levels in organ transplant patients.

The role of oxytocin in relation to female sexual arousal

Oxytocin is clearly involved in human reproduction and serves an important role in sexual arousal. Oxytocin serum levels were measured before and after sexual stimulation in 12 healthy women. Values of oxytocin 1 min after orgasm were significantly higher (p < 0.05) than baseline levels. This finding supports the hypothesis that oxytocin plays a major part in human sexual response both in neuroendocrine function and postcoital behavior.

Epinephrine application via an endotracheal airway and via the Combitube in esophageal position

OBJECTIVE

To compare plasma concentrations and cardiovascular effects of epinephrine after application via a conventional endotracheal airway and via the esophageal lumen of a new emergency airway, the esophageal tracheal Combitube.

DESIGN

Prospective, randomized study.

SETTING

Center for Biomedical Research, University of Vienna.

SUBJECTS

Fourteen juvenile swine received either an endotracheal tube (Group A) or a Combitube in esophageal position (Group B).

INTERVENTIONS

In Part I of the study, epinephrine was administered during spontaneous beating of the heart; in Part II, epinephrine was administered during cardiopulmonary resuscitation, using a ten-fold higher dosage in Group B, respectively.

MEASUREMENTS

Plasma epinephrine levels were measured 1, 2, 3, 5, 7, 10, 15, and 30 mins after application. Systolic arterial blood pressure and cardiac output in Part I, and end-tidal CO2 and coronary perfusion pressure in Part II were recorded.

MAIN RESULTS

In Part I, increased levels of plasma epinephrine and systolic arterial pressure were maintained significantly longer in Group B when compared with Group A. In Part II, no significant differences between the groups were found with regard to plasma epinephrine levels and hemodynamic variables.

CONCLUSION

Epinephrine applied via the esophageal lumen of the Combitube in a ten-fold higher dosage has similar effects on plasma epinephrine levels and hemodynamic variables compared to endotracheal administration.

Prevalence of C-cell hyperplasia in patients with normal basal and pentagastrin-stimulated calcitonin

The prevalence of thyroid C-cell hyperplasia (CCH) was investigated prospectively in 57 patients with normal preoperative pentagastrin-stimulated plasma concentrations of calcitonin (hCT, range, 1-60 pg/mL; normal, 100 pg/mL) who subsequently underwent total thyroidectomy due to thyrotoxicosis (n = 18) or to nodular thyroid disease in the presence (n = 9) or absence (n = 30) of cytological follicular neoplasia. CCH was seen in 28 of 57 (49%) of all patients. CCH was more common in hyperthyroid (12/18 [66%]) than in euthyroid (16/39 [41%] patients. No age- or gender-related differences in the occurrence of CCH was seen. There was no histological evidence of medullary thyroid carcinoma (MTC) in any patient. CCH classified histologically as neoplastic was encountered in two instances. It was concluded that CCH may be expected in almost 50% of normocalcitonemic patients with various thyroid disorders. Although the potential clinical importance of this histological finding and specifically its neoplastic variety remains unknown, these results are in keeping with the assumption that pentagastrin-stimulated plasma concentrations of hCT within the normal range do not exclude the presence of CCH.

High prevalence of hyperhomocysteinemia in critically ill patients

OBJECTIVE

To test the hypothesis that the prevalence of hyperhomocysteinemia is increased in critically ill patients and correlates with disease severity and mortality in these patients.

DESIGN

A prospective study.

SETTING

Three medical intensive care units at the University of vienna Medical School serving both medical and surgical patients.

PATIENTS

All consecutive admissions (n = 56) during a period of 4 wks. A total of 112 age- and gender-matched healthy individuals constituted the control group.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood samples were drawn within 24 hrs after admission for analysis of total homocysteine (tHcy), folate, vitamin B6 levels, and vitamin B12 levels as well as to identify the 677C-->T polymorphism in the gene coding for the enzyme 5,10-methylenetetrahydrofolate reductase. Acute Physiology and Chronic Health Evaluation III scores at admission and 24 hrs after admission as well as 30-day survival were documented in all patients. Hyperhomocysteinemia was more prevalent in critically ill patients (16.1%; 95% confidence interval, 7.6% to 28.3%) compared with age- and gender-matched healthy individuals (5.4%; 95% confidence interval, 2.0% to 11.3%; chi-square test; p = .022). There was no difference in tHcy plasma concentrations in the first 24 hrs after admission to an intensive care unit between survivors and nonsurvivors. The 5,10-methylenetetrahydrofolate reductase 677C-->T polymorphism had no influence on tHcy levels and survival of intensive care unit patients.

CONCLUSIONS

The prevalence of hyperhomocysteinemia is increased in critically ill patients compared to age- and gender-matched healthy individuals. The clinical significance of this finding remains to be determined.

Relationship of serum levels of endogenous relaxin to cervical size in the second trimester and to cervical ripening at term

OBJECTIVE

To assess whether cervical size in the early second trimester and cervical ripening at term may be related to serum levels of endogenous relaxin, 17beta-oestradiol or progesterone.

DESIGN

A cross-sectional study investigating the relationship between hormone concentrations and cervical parameters as measured by ultrasound and Bishop score, respectively.

PARTICIPANTS

Uncomplicated human pregnancies with normal fetal outcome, 72 women in the second trimester and 40 women at term.

METHODS

Vaginal ultrasound and palpation were used to estimate cervical parameters. Hormones were analysed either by dissociation-enhanced fluoroimmunoassay (relaxin) or by automated electrochemiluminescent immunoassays.

RESULTS

Cervical length and diameter correlated positively during mid-gestation and negatively at term. During mid-gestation, but not at term, relaxin was significantly associated with cervical length and volume, and with progesterone. Bishop score only correlated inversely with progesterone at term.

CONCLUSION

Corpus luteum function is reflected by progesterone and relaxin in the early second trimester. An impact of relaxin on cervical growth, previously demonstrated by animal models and in vitro experiments, was confirmed during human mid-gestation. In contrast to many other species, human cervical ripening was not associated with endogenous relaxin at term, but with decreased progesterone.

Acetaminophen has greater antipyretic efficacy than aspirin in endotoxemia: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To compare the antipyretic efficacy of aspirin and acetaminophen (INN, paracetamol) in 30 male volunteers with the use of endotoxin (lipopolysaccharide) to elicit a standardized febrile response.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in parallel groups. Subjects received an intravenous endotoxin bolus of 4 ng/kg after premedication with either placebo, 1000 mg aspirin, or 1000 mg acetaminophen by mouth.

RESULTS

Peak body temperatures were 38.5 degrees C +/- 0.2 degrees C in the placebo group, 37.6 degrees C +/- 0.2 degrees C in the acetaminophen group (P = .001 versus placebo), and 38.6 degrees C +/- 0.2 degrees C in the subjects treated with aspirin (P = .001 versus acetaminophen; P = .570 versus placebo) at 4 hours after lipopolysaccharide infusion. Subjective symptom scores for chills and perception of fever were higher in the placebo group than in the acetaminophen group (chills, 2.5 +/- 0.3 versus 1.0 +/- 0.2, P = .009 and fever, 2.5 +/- 0.2 versus 2.0 +/- 0.2, P = .021). Tumor necrosis factor-alpha, interleukin-6, and interleukin-8 levels rose by several orders of magnitude (P < .001 versus baseline in all groups), without significant intergroup differences.

CONCLUSIONS

Acetaminophen was the superior antipyretic drug in endotoxemia compared with aspirin. Treatment with acetaminophen ameliorates subjective symptoms induced by endotoxemia without compromising the humoral response of a subject to endotoxin. This observation has clinical interest and may also help to improve the lipopolysaccharide model, which can be used to test anti-inflammatory and anticoagulatory drugs.

Normal serum concentrations of sex hormone binding-globulin in patients with hyperthyroidism due to subacute thyroiditis

Serum concentrations of sex hormone binding-globulin (SHBG) were determined in patients with hyperthyroidism (n = 94; 12 men, 82 women) due to either Graves' disease (n = 59; 11 men, 48 women), autonomous thyroid adenomas (n = 23; 1 man, 22 women), or subacute thyroiditis (n = 12; all women). Elevated serum concentrations of SHBG were initially seen in 57 of 82 patients (69%) with hyperthyroidism due to either Graves's disease or due to autonomous adenoma. Elevated serum SHBG concentration was more frequent in patients with serum total thyroxine (TT4) concentrations greater than 15.0 microg/dL (32/39 [82%]; including 3 patients with autonomous adenoma) compared to those with serum TT4 concentration between 11.0 and 15.0 microg/dL (21/27 [77%]; including 7 patients with autonomous adenoma), or patients with an isolated elevation of serum total triiodothyronine (TT3) concentration (4/16 [25%]; including 2 patients with autonomous adenoma). Serum SHBG concentration normalized when patients became euthyroid. Only 1 of 12 patients in the hyperthyroid phase of subacute thyroiditis had an elevated serum concentration of SHBG. Serum concentrations of thyroid binding globulin (TBG) and transcortin (CBG) were normal in all but 1 patient. In patients with hyperthyroidism as a result of Graves' disease or autonomous adenoma serum SHBG concentrations were elevated with the greatest elevation found in patients with the highest serum T4 concentrations. The normal concentrations of SHBG in the hyperthyroid phase of subacute thyroiditis most likely reflects the shorter duration of exposure to increased thyroid hormone in this condition.

Results of the multicentre evaluation of an electrochemiluminescence immunoassay for HCG on Elecsys 2010

This study evaluated the performance of the HCG STAT Elecsys assay in 8 European laboratories using the Elecsys 2010 system. Analytical sensitivity was < 0.5 mlU/mL. The analysis of concentration series prepared by mixing serum pools with high and low HCG concentrations proved linearity up to 10.000 mIU/mL. A high-dose hook effect was not seen up to HCG concentrations of 430.000 mIU/mL. The medians of the within-run CVs (n = 21, 3 series) were 3.0% (2.1-5.8% CV; 10.4-14.4 mIU/mL), 2.4% (1.7-6.1% CV; 35.6-88.6 mIU/mL) and 2.3% (1.7-6.1% CV; 282.3-643.8 mIU/mL). The medians of the between-day imprecisions (n = 10-21) were 7.0% CV (5.2-12.0% CV; 4.0-14.0 mIU/mL), 5.5% CV (3.1-7.2% CV; 35.4-92.7% mIU/mL) and 4.1% CV (2.8-5.1% CV; 270.8-658.0 mIU/mL). The median recovery of two external quality control samples with assigned values of 9.39 and 10.40 mIU/mL) were 101.2 and 104.3% (ranges: 94.8-116.1%, 98.6-117.8%, n = 10). The assay was compared with five non-isotopic automated routine immunoassay systems (x). Slopes ranged from 0.87 to 1.15 and intercepts from-0.53 to 12.50 mIU/mL. The coefficients of correlation were with one exception (0.898) > or = 0.960. The distribution of HCG in samples from non-pregnant women and healthy men was very similar to that observed with other automated routine methods. The HCG Elecsys assay is very specific for the intact holo-hormone. Nicked HCG dimer, nicked and non-nicked beta-subunits are weakly recognised or not detected. Hemoglobin, bilirubin and lipemia (tested up to: Hb, 3.7 g/L; bilirubin, 500 mumol/L; triglyceride, 37.6 mmol/L) did not interfere the assay. The HCG Elecsys assay is well suited for the early and fast diagnosis of normal pregnancy and the detection of tubal pregnancy.

Elecsys TSH, FT4, T4, T-uptake, FT3 and T3. Clinical results of a multicentre study

6 assays for the assessment of thyroid function (TSH, FT4, T4, T-uptake, FT3 and T3) were targets of the International Multicenter Study on the random access analyzer Elecsys 2010. The aim of the study was to characterize the clinical performance of the assay in method comparison and reference range studies. The assays under evaluation were compared to a broad variety of radio isotopic and non-radio isotopic assays. They are suitable for serum and plasma samples. In case of TSH the study include 2nd and 3rd generation TSH procedures. In general, good to excellent correlations were found between the Elecsys and the respective routine methods. Systematic deviations were extraordinary low in case of TSH, FT4 and T4. Regarding the analysis of T3 and FT3 some systematic deviations in terms of standardization have been observed. Results of Elecsys T4 and Elecsys FT4 were independent of the serum total protein or serum albumin concentrations. In T3 and FT3 Elecsys the results of samples from NTI (non-thyroidal-illness) patients were decreased, reflecting the physiological situation in these patients. Studies using samples from healthy euthyroid as well as untreated hypo- and hyperthyroid individuals enabled us to assess the assays reference ranges.

Adrenal function in patients with chronic renal failure

Previous studies have reported divergent findings on the function of the hypothalamic-pituitary-adrenal axis in patients with chronic renal failure (CRF). The low-dose adrenocorticotropin (ACTH) test offers the possibility of unmasking adrenal dysfunction, which might remain undiscovered using the ACTH test with the standard 250-microg dose. Furthermore, the choice of renal replacement therapy (either hemodialysis or continuous ambulatory peritoneal dialysis [CAPD]) might have an impact on adrenal function. To investigate these possibilities, ACTH tests were performed with three different doses (ie, 1, 5, and 250 microg) in 14 CRF patients and in seven healthy controls. Seven of the CRF patients were receiving chronic hemodialysis and seven were receiving CAPD. Basal plasma concentrations of cortisol were comparable in the three groups tested (5.3+/-0.4 microg/dL in the controls, 6.6+/-0.7 microg/dL in the hemodialysis patients, and 7.9+/-1.0 microg/dL in the CAPD patients), whereas basal ACTH concentrations were significantly elevated in the CRF patients (28.5+/-3.8 pg/mL in the hemodialysis patients and 33.0+/-6.0 pg/mL in the CAPD patients) when compared with normal controls (17.0+/-1.4 pg/mL; P < 0.05). All three doses of ACTH resulted in a rapid increase of plasma cortisol concentrations that was comparable in all three groups. In the hemodialysis patients, a trend toward a diminished response to the lowest dose of 1 microg was noticed. We conclude, therefore, that adrenal response to ACTH in various doses is unaffected in CRF independent of whether hemodialysis or CAPD is chosen for renal replacement therapy.

Hyperprolactinemia, a tool in treatment control of tetrahydrobiopterin deficiency: endocrine studies in an affected girl

Severe tetrahydrobiopterin (BH4) deficiency is a naturally occurring model of cerebral catecholamine and serotonin shortage. Examination of the stimulated release and physiologic secretion pattern of several hormones in affected individuals permits certain conclusions concerning the involvement of these neurotransmitters in hormone regulation. Treatment, moreover, permits the ranking of the quality of the therapeutic regimens in use according to the degree of hormonal alteration. The 24-h secretion pattern of prolactin, GH, cortisol, and melatonin and the stimulated release of prolactin, GH, TSH, and gonadotropins were studied in an affected girl. Severe hyperprolactinemia with disruption of the pulsatile and circadian secretion pattern was the prevailing feature. The GH physiologic secretion pattern was not affected, but its stimulation was impaired. Melatonin displayed a normal circadian secretion pattern; the rhythm, however, was advanced by several hours. Conventional treatment of BH4 deficiency, i.e. BH4, 5-hydroxytryptophan, and L-DOPA/carbidopa (the last named given in three doses per day), suppresses prolactin levels merely for a few hours. L-DOPA/carbidopa given at shorter intervals or, even better, as a slow release preparation, is more effective in suppressing prolactin levels. Our data indicate immense hyperprolactinemia but few other hormonal disturbances in severe BH4 deficiency. Prolactin secretion may serve as an extremely sensitive marker for the hypothalamic dopamine content under different therapeutic regimens. Treatment with an L-DOPA/carbidopa slow release preparation produces virtually normal prolactin levels.