Growth hormone (GH) replacement therapy reduces serum sialic acid concentrations in adults with GH-deficiency: a double-blind placebo-controlled study

Patients with adult GH-deficiency are thought to have an increased risk of cardiovascular disease. Sialic acid (SA) concentrations have been proposed as a marker of atherosclerotic disease probably related to an inflammatory response of the arterial wall. SA as a marker of cardiovascular disease in adult GH-deficiency and its relation to changes in fasting lipid profile and hormone concentrations have not yet been investigated.

Long-term influence of different postmenopausal hormone replacement regimens on serum lipids and lipoprotein(a): a randomised study

To assess the influence of three different postmenopausal hormone replacement therapies on levels of serum lipids and lipoprotein(a) [Lp(a)].

Dilution and redistribution effects of rapid 2-litre infusions of 0.9% (w/v) saline and 5% (w/v) dextrose on haematological parameters and serum biochemistry in normal subjects: a double-blind crossover study

Although hypoalbuminaemia after injury may result from increased vascular permeability, dilution secondary to crystalloid infusions may contribute significantly. In this double-blind crossover study, the effects of bolus infusions of crystalloids on serum albumin, haematocrit, serum and urinary biochemistry and bioelectrical impedance analysis were measured in healthy subjects. Ten male volunteers received 2-litre infusions of 0.9% (w/v) saline or 5% (w/v) dextrose over 1 h; infusions were carried out on separate occasions, in random order. Weight, haemoglobin, serum albumin, serum and urinary biochemistry and bioelectrical impedance were measured pre-infusion and hourly for 6 h. The serum albumin concentration fell in all subjects (20% after saline; 16% after dextrose) by more than could be explained by dilution alone. This fall lasted more than 6 h after saline infusion, but values had returned to baseline 1 h after the end of the dextrose infusion. Changes in haematocrit and haemoglobin were less pronounced (7.5% after saline; 6.5% after dextrose). Whereas all the water from dextrose was excreted by 2 h after completion of the infusion, only one-third of the sodium and water from the saline had been excreted by 6 h, explaining its persistent diluting effect. Impedances rose after dextrose and fell after saline (P<0.001). Subjects voided more urine (means 1663 and 563 ml respectively) of lower osmolality (means 129 and 630 mOsm/kg respectively) and sodium content (means 26 and 95 mmol respectively) after dextrose than after saline (P<0.001). While an excess water load is excreted rapidly, an excess sodium load is excreted very slowly, even in normal subjects, and causes persistent dilution of haematocrit and serum albumin. The greater than expected change in serum albumin concentration when compared with that of haemoglobin suggests that, while dilution is responsible for the latter, redistribution also has a role in the former. Changes in bioelectrical impedance may reflect the electrolyte content rather than the volume of the infusate, and may be unreliable for clinical purposes.

Platelets increase while serum reduces the differentiation and activity of osteoclasts in vitro

Platelets modulate formation of osteoclasts and osteoblasts, but research with different preparations of platelets remains inconclusive. Here, we assessed whether serum components modulate the effect of platelet preparations. In murine bone marrow cultures, osteoclastogenesis was investigated in the presence of platelet-released supernatant (PRS), serum containing PRS (SC-PRS), and serum. Osteoclastogenesis was quantified by the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, TRAP activity and resorption assays. Also human osteoclastogenesis assays were performed. Viability and proliferation were tested by MTT and (3) [H]thymidine incorporation assays, respectively. Osteoblastogenesis was assessed by histochemical staining for alkaline phosphatase-of murine bone marrow cultures and human MG63 cells. We found PRS to increase the number of TRAP(+) multinucleated cells in the early phase and TRAP activity in the later phase of osteoclastogenesis. SC-PRS and serum decreased the number and activity of TRAP(+) multinucleated cells. Both serum containing preparations reduced viability and proliferation of hematopoietic progenitors. PRS decreased the numbers of alkaline phosphatase-positive colonies while SC-PRS and serum increased osteoblastmarkers in MG63. Proliferation of MG63 was stimulated by all preparations. These results show that activated platelets support osteoclastogenesis, while platelet preparations that contain serum components decrease osteoclastogenesis and increase osteoblastogenesis in vitro, suggesting that serum components modulate the effects of platelets on osteoclastogenesis and osteoblastogenesis.

Serum Concentrations of Mannan-Binding Lectin (MBL) and MBL-Associated Serine Protease-2 and the Risk of Adverse Events in Pediatric Patients With Cancer and Fever in Neutropenia

Background. It is unknown whether serum concentrations of mannan-binding lectin (MBL) and MBL-associated serine protease-2 (MASP-2) influence the risk of adverse events (AEs) in children with cancer presenting with fever in neutropenia (FN). Methods. Pediatric patients with cancer presenting with FN after non-myeloablative chemotherapy were observed in a prospective multicenter study. Mannan-binding lectin and MASP-2 were measured using commercially available enzyme-linked immunosorbent assay in serum taken at cancer diagnosis. Multiple FN episodes per patient were allowed. Associations of MBL and MASP-2 with AE in general, with bacteremia, and with serious medical complications (SMC) during FN were analyzed using mixed logistic regression. Results. Of 278 FN episodes, AE was reported in 84 (30%), bacteremia was reported in 42 (15%), and SMC was reported in 16 (5.8%). Median MBL was 2152 ng/mL (range, 7–10 060). It was very low (<100) in 11 (9%) patients, low (100–999) in 36 (29%) patients, and normal (�1000) in 79 (63%) patients. Median MASP-2 was 410 ng/mL (range, 68–2771). It was low (<200) in 18 (14%) patients and normal in the remaining 108 (86%) patients. Mannan-binding lectin and MASP-2 were not significantly associated with AE or bacteremia. Normal versus low MBL was independently associated with a significantly higher risk of SMC (multivariate odds ratio, 12.8; 95% confidence interval, 1.01–163; P = .050). Conclusions. Mannan-binding lectin and MASP-2 serum concentrations were not found to predict the risk to develop AEs or bacteremia during FN. Normal MBL was associated with an increased risk of SMC during FN. This finding, in line with earlier studies, does not support the concept of MBL supplementation in MBL-deficient children with cancer presenting with FN.

Comparison of paired serum and lithium heparin plasma samples for the measurement of serum amyloid A in horses using an automated turbidimetric immunoassay

This study aimed to evaluate whether equine serum amyloid A (SAA) concentrations could be reliably measured in plasma with a turbidimetric immunoassay previously validated for equine SAA concentrations in serum. Paired serum and lithium-heparin samples obtained from 40 horses were evaluated. No difference was found in SAA concentrations between serum and plasma using a paired t test (P=0.48). The correlation between paired samples was 0.97 (Spearman's rank P<0.0001; 95% confidence interval 0.95-0.99). Passing-Bablok regression analyses revealed no differences between paired samples. Bland-Altman plots revealed a positive bias in plasma compared to serum but the difference was not considered clinically significant. The results indicate that lithium-heparin plasma samples are suitable for measurement of equine SAA using this method. Use of either serum or plasma allows for greater flexibility when it comes to sample collection although care should be taken when comparing data between measurements from different sample types.

A phosphoinositide 3-kinase (PI3K)-serum- and glucocorticoid-inducible kinase 1 (SGK1) pathway promotes Kv7.1 channel surface expression by inhibiting Nedd4-2 protein

Epithelial cell polarization involves several kinase signaling cascades that eventually divide the surface membrane into an apical and a basolateral part. One kinase, which is activated during the polarization process, is phosphoinositide 3-kinase (PI3K). In MDCK cells, the basolateral potassium channel Kv7.1 requires PI3K activity for surface-expression during the polarization process. Here, we demonstrate that Kv7.1 surface expression requires tonic PI3K activity as PI3K inhibition triggers endocytosis of these channels in polarized MDCK. Pharmacological inhibition of SGK1 gave similar results as PI3K inhibition, whereas overexpression of constitutively active SGK1 overruled it, suggesting that SGK1 is the primary downstream target of PI3K in this process. Furthermore, knockdown of the ubiquitin ligase Nedd4-2 overruled PI3K inhibition, whereas a Nedd4-2 interaction-deficient Kv7.1 mutant was resistant to both PI3K and SGK1 inhibition. Altogether, these data suggest that a PI3K-SGK1 pathway stabilizes Kv7.1 surface expression by inhibiting Nedd4-2-dependent endocytosis and thereby demonstrates that Nedd4-2 is a key regulator of Kv7.1 localization and turnover in epithelial cells.

Pharmacokinetics of GHB and detection window in Serum and Urine after single uptake of a low dose of GLB - an Experiment with two volunteers

During the last few years γ-hydroxybutyric acid (GHB) and γ-butyrolactone (GBL) have attracted much interest as recreational drugs and knock-out drops in drug-facilitated sexual assaults. This experiment aims at getting an insight into the pharmacokinetics of GHB after intake of GBL. Therefore Two volunteers took a single dose of 1.5 ml GBL, which had been spiked to a soft drink. Assuming that GBL was completely metabolized to GHB, the corresponding amount of GHB was 2.1 g. Blood and urine samples were collected 5 h and 24 h after ingestion, respectively. Additionally, hair samples (head hair and beard hair) were taken within four to five weeks after intake of GBL. Samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after protein precipitation with acetonitrile. The following observations were made: spiked to a soft drink, GBL, which tastes very bitter, formed a liquid layer at the bottom of the glass, only disappearing when stirring. Both volunteers reported weak central effects after approximately 15 min, which disappeared completely half an hour later. Maximum concentrations of GHB in serum were measured after 20 min (95 µg/ml and 106 µg/ml). Already after 4-5 h the GHB concentrations in serum decreased below 1 µg/ml. In urine maximum GHB concentrations (140 µg/ml and 120 µg/ml) were measured after 1-2 h, and decreased to less than 1 µg/ml within 8-10 h. The Ratio of GHB in serum versus blood was 1.2 and 1.6

Aromatase deficiency caused by a novel P450arom gene mutation: impact of absent estrogen production on serum gonadotropin concentration in a boy.

We identified a new point mutation in the CYP19 gene responsible for aromatase (P450arom) deficiency in a 46,XY male infant with unremarkable clinical findings at birth. This boy is homozygote for a 1-bp (C) deletion in exon 5 of the aromatase gene causing a frame-shift mutation. The frame-shift results in a prematurely terminated protein that is inactive due to the absence of the functional regions of the enzyme. Aromatase deficiency was suspected prenatally because of the severe virilization of the mother during the early pregnancy, and the diagnosis was confirmed shortly after birth. Four weeks after birth, the baby boy showed extremely low levels of serum estrogens, but had a normal level of serum free testosterone; in comparison with the high serum concentration of androstenedione at birth, a striking decrease occurred by 4 weeks postnatally. We previously reported elevated basal and stimulated FSH levels in a female infant with aromatase deficiency in the first year of life. In contrast, in the male infant, basal FSH and peak FSH levels after standard GnRH stimulation tests were normal. This finding suggests that the contribution of estrogen to the hypothalamic-pituitary gonadotropin-gonadal feedback mechanism is different in boys and girls during infancy and early childhood. In normal girls, serum estradiol concentrations strongly correlate with circulating inhibin levels, and thus, low inhibin levels may contribute to the striking elevation of FSH in young girls with aromatase deficiency. In contrast, estradiol levels are physiologically about a 7-fold lower in boys than in girls, and serum inhibin levels remain elevated even though levels of FSH, LH, and testosterone are decreased.

Insulin increases serum leptin concentrations in children and adolescents with newly diagnosed type I diabetes mellitus with and without ketoacidosis.

AIMS/HYPOTHESIS The aims of this study were to analyse the changes of serum leptin in newly diagnosed children and adolescents with Type I (insulin-dependent) diabetes mellitus after insulin treatment and to examine the possible impact of ketoacidosis on these changes. METHODS Baseline serum leptin concentrations were measured in 28 newly diagnosed Type I diabetic patients [age 8.75 +/- 4.05 years (means +/- SD); BMI 15.79 +/- 2.47 kg/m(2); HbA(1 c) 11.3 +/- 1.9 %] with (n = 18) and without (n = 10) ketoacidosis before commencement of insulin treatment, at the time of diagnosis. Thereafter, during a 4-day course of continuous intravenous insulin injection to gain and maintain euglycaemia, serum leptin concentrations were assessed. RESULTS Baseline serum leptin concentrations, adjusted to age, BMI, sex and pubertal stage, differed among these patients. There was, however, an increase of leptin in all subjects from 1.37 +/- 0.56 ng/ml (mean +/- SD) up to 2.97 +/- 1.52 ng/ml by 117 % (p < 0.0001) after insulin therapy. On average, peak serum leptin concentration was obtained after 42 h of insulin treatment. Further, there was no difference in the mean increase of serum leptin concentrations in the two groups, namely with and without ketoadicosis, of insulin-dependent diabetic children and adolescents. In addition, there was no correlation between serum leptin concentrations and correction of ketoacidosis during insulin treatment. CONCLUSIONS/INTERPRETATION Insulin increases serum leptin, within 1 day, in children and adolescents with newly diagnosed Type I diabetes. Ketoacidosis does not influence this interaction between insulin and leptin.

Rising serum sodium levels are associated with a concurrent development of metabolic alkalosis in critically ill patients

PURPOSE Changes in electrolyte homeostasis are important causes of acid-base disorders. While the effects of chloride are well studied, only little is known of the potential contributions of sodium to metabolic acid-base state. Thus, we investigated the effects of intensive care unit (ICU)-acquired hypernatremia on acid-base state. METHODS We included critically ill patients who developed hypernatremia, defined as a serum sodium concentration exceeding 149 mmol/L, after ICU admission in this retrospective study. Data on electrolyte and acid-base state in all included patients were gathered in order to analyze the effects of hypernatremia on metabolic acid-base state by use of the physical-chemical approach. RESULTS A total of 51 patients were included in the study. The time of rising serum sodium and hypernatremia was accompanied by metabolic alkalosis. A transient increase in total base excess (standard base excess from 0.1 to 5.5 mmol/L) paralleled by a transient increase in the base excess due to sodium (base excess sodium from 0.7 to 4.1 mmol/L) could be observed. The other determinants of metabolic acid-base state remained stable. The increase in base excess was accompanied by a slight increase in overall pH (from 7.392 to 7.429, standard base excess from 0.1 to 5.5 mmol/L). CONCLUSIONS Hypernatremia is accompanied by metabolic alkalosis and an increase in pH. Given the high prevalence of hypernatremia, especially in critically ill patients, hypernatremic alkalosis should be part of the differential diagnosis of metabolic acid-base disorders.

Disorders of serum sodium in emergency patients: salt in the soup of emergency medicine

Electrolyte disorders are common and potentially fatal laboratory findings in emergency patients. Approximately 20 % of patients in the emergency department present with either hyponatremia or hypernatremia. Recently it was shown that disorders of serum sodium are not only an expression of the severity of the underlying disease but independent predictors for the outcome of patients. They directly influence patient daily life by causing not only gait and concentration disturbances but also an increased tendency to fall together with a reduced bone mass. Given these new data it is even more important to detect and adequately correct dysnatremia in patients in the emergency department. Acute, symptomatic dysnatremia should be corrected promptly by use of 3 % NaCl for hyponatremia and 5 % glucose for hypernatremia. A close monitoring of serum sodium concentration is, however, essential in any case of correction of hyponatremia or hypernatremia in order to avoid rapid overcorrection and subsequent complications. A profound knowledge of the mechanisms underlying the development of hyponatremia, e.g. diuretics, syndrome of inappropriate antidiuretic hormone secretion (SIADH), heart failure and cirrhosis of the liver and hypernatremia, e.g. dehydration, infusions, diuretics and osmotic diuresis is essential. The present article describes the epidemiology, etiology and correction of hyponatremia and hypernatremia on the basis of current knowledge with special emphasis on emergency department patients.