Direct comparison of regulators of calcification between bone and vessels in humans

Calcification is not only physiologically present in bone but is a main pathophysiological process in vasculature, favouring cardiovascular diseases. Our aim was to investigate changes in the expression of calcification regulators during vascular calcification in bone and vasculature. Levels of gene expression of osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), osteopontin (OPN), matrix gla protein (MGP), bone sialoprotein (BSP), SMAD6, and runt-related transcription factor 2 (RUNX2) were determined in bone, aorta, and external iliac artery tissue samples of transplant donors. Histological stages of atherosclerosis (AS) in vessels are defined as "no changes", "intima thickening", or "intima calcification". Patients' bone samples were subgrouped accordingly. We demonstrate that in vessels BSP and OPN expression significantly increased during intima thickening and decreased during intima calcification, whereas the expression of regulators of calcification did not significantly change in bone during intima thickening and intima calcification. At the stage of intima thickening, MGP, OPG, and SMAD6 expression and at stage of intima calcification only MGP expression was lower in bone than in vessel. The expression of BSP and RANKL was regulated in opposite ways in bone and vessels, whereas the expression of MGP, OC, RUNX2, and OPN was regulated in a tissue-specific manner. Our study is the first direct comparison of gene expression changes during AS progression in bone and vessels. Our results indicate that changes in the expression of regulators of calcification in the vessel wall as well as in bone occur early in the calcification process, even prior to deposition of calcium/phosphate precipitation.

Testosterone to dihydrotestosterone ratio as a new biomarker for an adverse metabolic phenotype in the polycystic ovary syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a heterogeneous disease with many different aspects, including hyperandrogenism and metabolic disturbances. Clinical phenotypes show different patterns of steroid hormones that have been investigated to some extent.

OBJECTIVE

This study intended to determine the role of the testosterone (TT) to dihydrotestosterone (DHT) ratio (TT/DHT ratio) in PCOS patients and to further assess the correlation of this ratio with hormonal, anthropometric, and metabolic parameters.

DESIGN AND SETTING

Serum samples of 275 premenopausal PCOS patients fulfilling Rotterdam criteria and 35 BMI-matched, premenopausal, healthy controls were analyzed for testosterone, DHT, dehydroepiandrosterone (DHEA), and androstenedione using liquid chromatography/mass spectrometry.

MAIN OUTCOME MEASURES

We measured total levels of testosterone and DHT and calculated unbound hormone levels as well as the ratio of testosterone to DHT. Further, impaired glucose tolerance, basal and stimulated serum insulin levels, metabolic syndrome and insulin resistance according to the homeostatic model assessment (HOMA-IR) were assessed.

RESULTS

PCOS patients showed significantly higher levels of TT (P < .001), free testosterone (P < .001), and free DHT (P < .001) compared to healthy controls. The TT/DHT ratio was significantly higher in PCOS patients (P < .001). No difference was found for total DHT levels (P = .072). In PCOS patients alone, the TT/DHT ratio was significantly higher in obese patients (P < .001) and patients with metabolic syndrome (P < .001), impaired glucose tolerance (IGT) (P < .001) or insulin resistance (P < .001). Significant correlations of the TT/DHT ratio with various adverse anthropometric, hormonal, lipid and liver parameters and parameters of glucose metabolism were found.

CONCLUSION

Our data provide evidence for a strong link between a high TT/DHT ratio and an adverse metabolic phenotype in PCOS patients. This correlation was only found in PCOS patients, suggesting the TT/DHT ratio to be a new biomarker for an adverse metabolic phenotype in PCOS patients.

Epidemiology of proximal humeral fractures in Austria between 1989 and 2008

Incidence rates of proximal humeral fractures in Austria over a period of twenty years (1989-2008) were estimated. Age standardized incidence rates increased until 2008, primarily driven by an increase in incidence rates in women.

INTRODUCTION

The aim of the prevailing study was to estimate incidence rates of proximal humeral fractures and to assess changes in trend in the Austrian population aged 50 years and above, over a period of 20 years (1989-2008).

METHODS

Number of proximal humeral fractures were obtained from the Austrian Hospital Discharge Register for the entire population >50 years of age. Adjustment factors were determined for multiple registrations of the same diagnosis, and for the fact that not all patients with proximal humeral fractures are treated in an inpatient setting. To analyze the overall change in this type of fracture for the period, average annual changes expressed as incidence rate ratios were calculated.

RESULTS

The estimated age-standardized incidence (fractures per 100,000 individuals) of proximal humeral fractures among Austrians >50 years of age increased in men from 112 (95% CI, 99-124) to 141 (129-153) and in women from 222 (202-241) to 383 (360-406). The increase appeared to be linear with no leveling off towards the end of the study period.

CONCLUSION

While some caution is necessary when interpreting the results given the use of adjustment factors, there appears to have been a rise in the incidence of proximal humeral fractures in Austria in both men and women, with no leveling off in recent years. The reasons for this are not clear, but in the light of previously reported leveling off in the increase in the incidence of hip fractures, a change in the patterns of falls cannot be ruled out.

Epidemiology of hip fractures in Austria: evidence for a change in the secular trend

Hip fracture incidence rates in Austria over a period of 20 years (1989-2008) were assessed. Age-standardized incidence rates increased until 2005 but decreased thereafter. This change in the secular trend was primarily driven by a decrease in hip fracture incidence in women.

INTRODUCTION

The aim of the prevailing study was to assess the incidence rates of hip fractures including changes in trend in the Austrian population over a period of 20 years (1989-2008).

METHODS

The number of hip fractures was obtained from the Austrian Hospital Discharge Register for the entire population ≥ 50 years of age. A correction factor for multiple registrations of the same diagnosis was determined. Incidence rates (cases per 100,000) of hip fracture were calculated in 5-year age intervals. To analyze the overall change in hip fracture for the period, average annual change expressed as incidence rate ratios (IRRs) was calculated.

RESULTS

The age-standardized incidence in women increased until 2005, from 493 to 642, and decreased thereafter. In men, it increased at a measured pace until 2006, from 192 to 280, and decreased thereafter with a slight rebound in 2008. The age-standardized incidence in the entire population increased until 2005, from 376 to 496, and decreased thereafter. The IRR for the last 3 years (2006-2008) was significantly below the IRR for the first 17 years (0.94, ρ < 0.01), driven by a lower IRR in women (0.91, ρ < 0.01) and to a lesser extent by a lower IRR (not statistically significant) in men (0.96, ρ < 0.15).

CONCLUSION

The present study indicates that since 2006, age-standardized incidence of hip fractures has been declining in the Austrian population aged 50 years and above. This reversal in the secular trend has primarily been driven by a decrease in hip fracture incidence in women.

[Monitoring of glucose concentration in critical patients, comparing arterial blood glucose concentrations and interstitial glucose concentration measured by microdialysis technique]

INTRODUCTION

Recent studies have shown that normalization of blood glucose in critically ill patients by intensive insulin therapy significantly decreases their mortality and morbidity. The aim of our study was to compare interstitial glucose concentrations in subcutaneous adipose tissue (measured by microdialysis technique) and arterial blood glucose concentrations to test the suitability of subcutaneous adipose tissue for long-term placement of biosensors for glucose measurement in critically ill patients.

PATIENTS AND METHODS

20 patients (16 men and 4 women) after cardiac surgery hospitalized at postoperative intensive care unit were included into the study. Mean age was 68 +/- 10 years, BMI was 28.3 +/- 3.9 year. Only patients with glycemia higher than 6.7 mmol/l at a time of admission to the ICU were included. Samples for measurement of interstitial glucose concentrations were collected in 60 minutes intervals during 48 hours using microdialysis of the subcutaneous adipose tissue. Perfusion fluid was 5% mannitol, perfusion rate was 1 microl/min. Arterial blood glucose concentration was measured in 60 minutes intervals, absolute concentrations of interstitial glucose were calculated using ionic reference technique.

RESULTS

Mean arterial glucose concentration during the study was 6.7 +/- 0.56 mmol/l, absolute concentration of glucose in interstitial fluid was 3.55 +/- 0.58 mmol/l. Mean correlation coefficient between arterial and interstitial concentrations was 0.77 +/- 0.15.

CONCLUSION

Our study demonstrated good correlation between interstitial glucose concentrations in subcutaneous adipose tissue and arterial blood glucose concentrations in post-cardiac surgery patients. Further studies are needed to evaluate this relationship in patients with more severely disturbed perfusion of subcutaneous adipose tissue.

Second-line treatment of limb-threatening diabetic foot infections with intravenous fosfomycin

Diabetic foot infections (DFI) expanding to bones and joints are associated with a poor prognosis of limb salvage. The bactericidal epoxide fosfomycin accumulates in inflamed soft and bone tissue, and may represent a potential treatment option for targeting severe DFI. Fifty-two patients (35 men, 17 women, mean age 62.9 +/- SD 9.2 years) with limb-threatening DFI (that is, Wagner grade 3 and higher) were enrolled in a multi-center compassionate use program of fosfomycin. Twenty-two patients (42.4%) had unsuccessfully been pretreated with other antimicrobials. Besides standard treatment (topical wound care and surgical debridement), eligible subjects received a combination of 8 to 24 g fosfomycin daily, and a conventional antibiotic agent, usually a beta-lactam compound. Treatment duration averaged 14.4 +/- 8.3 days. Limb-sparing surgery was possible in 48 patients (92.3%, 95% confidence interval 81.5-97.9%). Only four participants faced mild drug-related side effects (nausea, rash). Logistic regression analysis showed a trend towards better results with prolonged treatment, whereas a dose increase above 12 g daily did not affect outcomes. In DFI being resistant to conventional antibiotic agents, intravenous fosfomycin offers an effective treatment choice that may increase the likelihood of limb preservation. The present data warrant a larger comparative trial to stabilize effect estimates.

A double-blind randomized-phase II trial comparing immunization with antiidiotype goat antibody vaccine SCV 106 versus unspecific goat antibodies in patients with metastatic colorectal cancer

This article reports on the first double-blind randomized clinical study with an antiidiotype antibody vaccine in patients with metastatic colorectal carcinoma. The study was performed to determine immunological parameters, efficacy, and tolerability of the vaccine. Forty-two patients with metastatic colorectal cancer were randomly assigned to multiple immunizations with goat IgG antiidiotype vaccine SCV 106 (n = 21) or unspecific goat IgG as controls (n = 21). The antiidiotype vaccine mimicked the 17-1A glycoprotein antigen associated with colorectal cancer. Of the 42 patients entered, 39 were evaluable for efficacy (SCV 106, n = 18; controls, n = 21). Twenty-nine patients raised antibodies to the vaccines (immunological responders, SCV 106, n = 12; controls, n = 17). Only in the SCV 106 group was a significant increase (p = 0.002) of titers with specificity of antitumor antibody 17-1A found. According to the International Union Against Cancer (UICC) criteria no tumor response was observed. However, in the SCV 106 group the relative increase of carcinoembryonic antigen (CEA) levels between entry and observed disease progression was lower (p = 0.03) and disease progression was determined less frequently by development of new metastases (p = 0.001). On an intention-to-treat basis, the survival time difference between the two groups was not significant. Comparison of immunological responders in both groups revealed a significant survival advantage of the SCV 106-treated patients compared with controls (mean 67 versus 39 weeks; p = 0.01). Immunizations were well tolerated. Vaccination of immunologically responding metastatic colorectal carcinoma patients with SCV 106 leads to slowed disease progression and tumor dissemination and significantly prolongs survival time.

Comparative evaluation of three assay systems for automated determination of hemoglobin A1c

We evaluated three newly introduced systems for automated determinations of hemoglobin (Hb) A1c, which allow the processing of large amounts of samples in a routine clinical laboratory. We compared these methods--the Variant HPLC, the Hi-Auto A1c analyzer system, and the Roche immunoassay--with the Diamat HPLC system. All showed good precision and good concordance with the Diamat HPLC. The reference range for Hb A1c has to be determined by the laboratory for each assay system. Interference study showed no statistically significant influence of anemia, polycythemia, rheumatoid factor, or chronic hemodialysis, although individual Hb A1c values can be influenced by polycythemia (when measured with the Hi-Auto A1c analyzer) and by chronic hemodialysis (when measured with the Variant HPLC). HPLC was not suitable for measuring Hb A1c in the examined cases of hemoglobin variants; assaying fructosamine seems to be better for monitoring these patients.

Troponin T as a marker for posttransplantation adaptational problems of the donor heart

BACKGROUND

Troponin T is used as a marker for myocardial cell damage (e.g., in aiding diagnosis and follow-up of myocardial infarction). Elevated troponin T levels are also observed after heart transplantation, although until now no explanation could be found for this phenomenon.

METHODS AND RESULTS

Serum samples of 15 patients who underwent orthotopic heart transplantation were tested for troponin T with a one-step enzyme immunoassay. The highest concentrations of troponin T were seen between day 3 and 14 after transplantation (3.05 +/- 1.30 micrograms/L) and remained elevated up to 3 months. A correlation (r = 0.61, p < 0.02) was found between pretransplantation systolic pulmonary artery pressure and the cumulative troponin T release after transplantation. No association was found with rejection, and no correlation was found with ischemic time of the donor heart.

CONDITIONS

These findings support the hypothesis that the acute exposure of the donor heart to the preexisting elevated right ventricular afterload in the recipient represents a strong mechanical stress for the transplanted heart. Measurement of troponin T may therefore be helpful in the posttransplantation monitoring and management of ventricular function after orthotopic heart transplantation.

Insulin-like growth factor-I inhibits insulin and amylin secretion in conscious rats

Human recombinant insulin-like growth factor-I (IGF-I) exerts insulin-like antidiabetic properties in vitro and in vivo. To determine the effects of IGF-I infusion on insulin and amylin release, plasma glucose of freely moving undisturbed rats was constantly maintained at 13.9 mmol/liter by variable glucose infusion for 120 min in three groups of fasted Sprague-Dawley rats (hyperglycemic clamp technique). Group A, vehicle infusion (control group); group B, bolus 0.39 nmol plus 0.39 nmol/h IGF-I continously; and group C, bolus 1.96 nmol plus 1.96 nmol/h IGF-I continuously. During the steady-state phase of the experiment, IGF-I dose dependently reduced plasma insulin (pmol/liter: A, 718 +/- 58; B, 613 +/- 35, NS vs. A; C, 408 +/- 21, P < 0.01 vs. A; dose-response effect: P < 0.0001), plasma amylin (pmol/liter: A, 10.2 +/- 0.6; B, 8.8 +/- 0.5, NS vs. A; C, 5.8 +/- 0.4, P < 0.01 vs. A; dose-response effect: P < 0.0001), and net glucose uptake (mumol/kg.min: A, 188 +/- 12; B, 160 +/- 12, NS vs. A; C, 134 +/- 7, P < 0.01 vs. A; dose-response effect: P < 0.0025). At the same time, the ratio of plasma insulin/plasma amylin (mol/mol: A, 72 +/- 6; B, 71 +/- 5; C, 74 +/- 9; NS), the ratio of net glucose uptake/plasma insulin (mumol/kg.min per pmol/liter: A, 0.28 +/- 0.03; B, 0.27 +/- 0.02; C, 0.36 +/- 0.04; NS), and glycogen content of liver, heart, and various hindlimb muscles remained unaffected. The results demonstrate that IGF-I is a potent inhibitor of insulin and amylin release in healthy rats exposed to hyperglycemia and suggest that IGF-I infusion inhibits hormone secretion from pancreatic beta cells at infusion rates that do not affect insulin-stimulated glucose uptake by peripheral tissues.

Islet amyloid polypeptide inhibits insulin secretion in conscious rats

To investigate the effect of islet amyloid polypeptide (IAPP, amylin) exposure on insulin secretion in vivo, the plasma glucose level of conscious rats was clamped at 11.1 mmol/l (hyperglycemic clamp) during the last 2 h of a 24-h infusion study. Group parameters were A, 24-h saline; B and C, 22-h saline followed by 2-h IAPP (B, 8.5 pmol/min; C, 85 pmol/min), and D, 24-h IAPP (85 pmol/min). Induced hyperglycemia increased plasma insulin concentration by 426 +/- 34 pmol/l in control rats (group A). This effect on plasma insulin was reduced by 31% and 53% during short-term IAPP infusion (group B, 8.5 pmol/min, 294 +/- 41 pmol/l; C, 85 pmol/min, 202 +/- 25 pmol/l; short-term effect, P < 0.0001), whereas insulin levels tended to increase after 24 h of continuous IAPP exposure (group D, 682 +/- 120 pmol/l; P < 0.05 vs. group A). Glucose infusion rate required to maintain constant hyperglycemia fell dose dependently during short-term but not during long-term IAPP infusion (mumol.kg-1.min-1: group A, 203 +/- 11; B, 154 +/- 7; C, 119 +/- 7; D, 212 +/- 9; short-term effect, P < 0.0001). In parallel, muscle glycogen content was dose dependently reduced by short-term IAPP exposure. We conclude that IAPP inhibits glucose-stimulated insulin secretion and decreases muscle glycogen storage in conscious rats in vivo.

[Photometric determination of HbA1c levels in clinical practice]

This study was undertaken to evaluate the routine use of a new immunological photometer to measure the concentration of HbA1c in whole blood from 155 patients. The basis of the measurement is a latex agglutination reaction in which a monoclonal antibody as epitope recognizes glucose bound to HbA1c. The result is available within 9 min. High-pressure liquid chromatography (HPLC) served as control method. The photometer proved to be very precise (all coefficients of variant < 2.5%), and the values obtained agreed well with those by HPLC (y = 0.952x-0.12; r = 0.986; P < 0.001). The reference ranges for the photometrically measured HbA1c values (4.4-5.9%), obtained for 40 patients, agreed well with those by HPLC (4.6-6.2%). Interference study discovered no effect on the measured value by anaemia, polycythaemia or high rheuma factor (n = 31). In 12 patients on dialysis the photometer recorded significantly lower values than HPLC (P < 0.0005). It is possible that in these cases the photometer values are more accurate because the method is not affected by carbamylated haemoglobin. False results were obtained by the photometer in two patients with leucocytosis (79,000 and 216,000/microliters, respectively) due to chronic lymphocytic leukaemia.

Automated determination of glycated hemoglobin: comparative evaluation of five assay systems

We evaluated four newly introduced assays for determination of glycated hemoglobin allowing the processing of large amounts of samples in a clinical routine laboratory. These methods were compared to the Bio-Rad Diamat system. The investigated methods were the Merck Hitachi L-9100, a fully automated HPLC analyser, the Abbott IMx glycated hemoglobin ion capture assay, the DAKO HbA1c enzyme linked immunosorbent assay (ELISA), and the Boehringer-Mannheim HbA1c Tinaquant turbidimetric assay. All methods showed generally acceptable precision and good accordance with the Diamat system. Interference study showed influence of anaemia, polycythemia, rheumatoid factor, and chronic hemodialysis on the values of the DAKO ELISA and of anaemia and polycythemia on the values of the Boehringer-Mannheim Tinaquant assay. All of the investigated methods allow referring of results either as measured or standardized HbA1c values, the latter obtained after calibration with reference to an ion exchange high-pressure liquid chromatography method. Our data confirm the feasibility of this kind of standardisation of glycated hemoglobin assays, allowing direct comparison of results from various determination methods.

Insulin resistance caused by amylin in conscious rats is independent of induced hypocalcemia and fades during long-term exposure

To compare the effect of short- vs long-term amylin infusion on insulin sensitivity, glucose tolerance and serum calcemia, euglycemic-hyperinsulinemic clamp (26 pmol.kg-1 x min-1) and glucose tolerance tests (2.4 mmol/kg over 30 min) were performed in lean Zucker rats. Three infusion protocols were employed: control group: 24 h of i.v. saline; short-term amylin exposure: 22 h of i.v. saline followed by 2 h of i.v. amylin (20 micrograms/h); long-term amylin exposure: 24 h of iv amylin (20 micrograms/h). Insulin resistance was induced by short-term amylin infusion during euglycemic clamping, as shown by a 41% decrease in space-corrected glucose infusion rates (mumol.kg-1 x min-1; control group, 106.0 +/- 15.0; short-term i.v. amylin, 62.7 +/- 15.0; p < 0.005). After long-term amylin exposure, insulin sensitivity was identical to control values (109.9 +/- 6.7). This fading action of amylin was confirmed by data from the glucose tolerance test, demonstrating glucose intolerance after short- but not after long-term amylin exposure. Serum calcium concentration decreased during short-term (2 h) amylin infusion (from 2.52 +/- 0.15 to 2.09 +/- 0.12 mmol/l; p < 0.01) and hypocalcemia of a similar extent also was present after 22 h and 24 h of amylin exposure (2.10 +/- 0.09 and 2.04 +/- 0.14 mmol/l, respectively). The data demonstrate that short-term amylin infusion induces insulin resistance and glucose intolerance, both of which vanish during long-term (> 22 h) amylin exposure, being apparently independent of induced hypocalcemia.

Acute effects of amiodarone on ultrastructure and electrical activity of isolated guinea pig hearts

STUDY OBJECTIVE

The aim was to evaluate the effects of tissue concentration of amiodarone on ultrastructure and electrical activity in isolated spontaneously beating Langendorff perfused guinea pig hearts.

DESIGN

Group 1: The influence of 10 microM amiodarone over a period of 1 h in a non-recirculated perfusate on conduction intervals, heart rate, creatine kinase concentration in the coronary effluent, coronary flow, and drug accumulation was determined. Group 2: Ultrastructural changes after 30 min and 60 min perfusion with amiodarone were examined. Group 3: Cardiac refractoriness was evaluated following 30 min and 60 min of perfusion with amiodarone. EXPERIMENTAL PREPARATIONS: Isolated hearts of guinea pigs (200-300 g) were used: group 1, n = 6 animals; group 2, n = 3 for each time span; and group 3, n = 6 for each time span.

MEASUREMENTS AND MAIN RESULTS

A steady state for the effects of amiodarone on atrioventricular and intraventricular conduction [+31(SEM 5)%, p less than 0.01% +47(12)%, p less than 0.01, respectively] and on heart rate [-30(9)%, p less than 0.01] was reached after 15 min, and on His bundle conduction [+38(17)%, p less than 0.01] after 30 min. QT duration was not affected throughout the duration of the experiment. Cardiac refractoriness was significantly prolonged following 30 min perfusion with 10 microM amiodarone, and was further significantly increased following 60 min perfusion. Amiodarone tissue concentration increased to 365(39) nmol.g-1 wet weight, and this was accompanied by an increase in creatine kinase concentration in the coronary effluent. Coronary flow stayed constant throughout the whole experiment. At the end of the experiment electron microscopic examination of the myocardium of the left ventricle showed accumulation, fusion, and vacuolisation of mitochondria, and perinuclear oedema.

CONCLUSIONS

These observations suggest that amiodarone, as well as exerting acute electrophysiological effects, creates ultrastructural changes which probably contribute to its effectiveness in arrhythmias caused by scarred myocardium.

[Insulin-sulfonylurea combination therapy in secondary therapy failure with sulfonylurea compounds. Randomized study between evening and morning intermediary insulin administration using the Novo Pen semi-automatic insulin injector]

In 28 type II diabetics with secondary failure of sulfonylurea treatment, the efficacy and safety of combined therapy with insulin and glibenclamide were investigated. Patients were randomized in two groups and treated for 16 weeks either with insulin Novo Protaphan HM Penfill (100 IU/ml "bed time") and 10 mg of glibenclamide in the morning (group A), or with insulin Novo Actraphan HM Penfill 100 IU/ml in the morning combined with two 5 mg doses of glibenclamide at lunchtime and in the evening (group B). Subsequently a dropout trial of sulfonylurea was performed in half of the patients. Mean blood glucose levels were lowered in the whole group of patients from 13.5 +/- 1.8 mmol/l to 8.8 +/- 2.3 mmol/l after 8 weeks and 8.7 +/- 1.8 mmol/l after 16 weeks, and the HbAlc from 10.1 +/- 1.2% to 8.4 +/- 1.0% and 7.8 +/- 1.0% respectively. After a glibenclamide dropout period of one or two weeks in 14 of the patients, the mean blood glucose level rose significantly by 2.8 +/- 2.6 mmol/l. Only 2 patients did not show this increase. The mean insulin consumption was 13 +/- 3 IU after 8 weeks and 14 +/- 5 IU after 16 weeks respectively, and the incidence of hypoglycemia one in 12 weeks of treatment. The combination of glibenclamide and insulin (administered with the Novo Pen injector) is a safe and effective form of therapy in secondary failure of sulfonylurea, and is well accepted due to the mild start into insulin therapy.