Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology.

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Left atrial appendage occlusion in recurrent ischaemic stroke, a multicentre experience.

BACKGROUND: Oral anticoagulation therapy (OAC) remains the gold standard for ischaemic stroke prevention in patients with non-valvular atrial fibrillation (NVAF) and elevated stroke risk. Percutaneous left atrial appendage occlusion (LAAO) has emerged as a potential alternative for stroke prevention in patients who cannot tolerate OAC. Although no randomized data is available, recurrent stroke in NVAF-patients, while on adequate OAC, is regarded as a treatment failure and therefore is considered as a potential indication for LAAO, based upon expert opinion. METHODS/OBJECTIVES: A multicentre retrospective cohort study evaluating efficacy, safety and mortality of LAAO in NVAF-patients presenting with recurrent ischaemic stroke, after excluding other plausible causes. RESULTS: Fifteen LAAO have been performed in NVAF-patients with recurrent stroke despite ongoing OAC, after exclusion of other plausible causes. Mean age was 78.1 ± 5.8 years, mean CHA2DS2-VASc-score = 6 ± 1.2 and mean HAS-BLED-score = 5 ± 1.2. Successful implantation was achieved in all patients (73% Amplatzer device and 27% Watchman device), without any access-related complications and only one procedure/device-related complication (device embolization) was reported. In all but four patients, OAC was continued at long term after LAAO. No haemorrhagic strokes and only two ischaemic strokes were observed. During follow-up three patients died, all due to non-atrial fibrillation or non-device-related causes. CONCLUSIONS: In NVAF-patients at high risk for stroke presenting with recurrent stroke despite adequate OAC, LAAO may be considered an adjunctive, but not alternative treatment to OAC with high feasibility and safety.Abbreviations: AF: atrial fibrillation; ESC: European Society of Cardiology; INR: international normalized ratio; LAA: left atrial appendage; LAAO: left atrial appendage occlusion; NOAC: non-vitamin K oral anticoagulants; NVAF: non-valvular atrial fibrillation; OAC: oral anticoagulation; RS: recurrent (ischaemic) stroke; SD: standard deviation; TIA: transient ischaemic attack; TOE: transoesophageal echocardiography; TTE: transthoracic echocardiography; VKA: vitamin K antagonists.

Diagnostic performance of seven rapid IgG/IgM antibody tests and the Euroimmun IgA/IgG ELISA in COVID-19 patients.

OBJECTIVES: To evaluate the diagnostic performance of seven rapid IgG/IgM tests and the Euroimmun IgA/IgG ELISA for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in COVID-19 patients. METHODS: Specificity was evaluated in 103 samples collected before January 2020. Sensitivity and time to seropositivity was evaluated in 167 samples from 94 patients with COVID-19 confirmed with RT-PCR on nasopharyngeal swab. RESULTS: Specificity (confidence interval) of lateral flow assays (LFAs) was ≥91.3% (84.0-95.5) for IgM, ≥90.3% (82.9-94.8) for IgG, and ≥85.4% (77.2-91.1) for the combination IgM OR IgG. Specificity of the ELISA was 96.1% (90.1-98.8) for IgG and only 73.8% (64.5-81.4) for IgA. Sensitivity 14-25 days after the onset of symptoms was between ≥92.1% (78.5-98.0) and 100% (95.7-100) for IgG LFA compared to 89.5% (75.3-96.4) for IgG ELISA. Positivity of IgM OR IgG for LFA resulted in a decrease in specificity compared to IgG alone without a gain in diagnostic performance, except for VivaDiag. The results for IgM varied significantly between the LFAs with an average overall agreement of only 70% compared to 89% for IgG. The average dynamic trend to seropositivity for IgM was not shorter than for IgG. At the time of hospital admission the sensitivity of LFA was <60%. CONCLUSIONS: Sensitivity for the detection of IgG antibodies 14-25 days after the onset of symptoms was ≥92.1% for all seven LFAs compared to 89.5% for the IgG ELISA. The results for IgM varied significantly, and including IgM antibodies in addition to IgG for the interpretation of LFAs did not improve the diagnostic performance.

Free Testosterone Reflects Metabolic as well as Ovarian Disturbances in Subfertile Oligomenorrheic Women.

BACKGROUND: Diagnosing polycystic ovary syndrome (PCOS) is based on ovulatory dysfunction, ovarian ultrasound data, and androgen excess. Total testosterone is frequently used to identify androgen excess, but testosterone is mainly bound to sex hormone-binding globulin (SHBG) and albumin. Only 1-2% of nonprotein-bound testosterone (so-called free testosterone) is biologically active and responsible for androgen action. Moreover, automated immunoassays which are frequently used for female testosterone measurements are inaccurate. OBJECTIVE: To assess the clinical usefulness of liquid chromatography-tandem mass spectrometry measured testosterone and calculated free testosterone in subfertile women attending a fertility clinic with oligomenorrhea and suspected PCOS. METHODS: Hormonal and metabolic parameters were evaluated, and ovarian ultrasound was performed. Total testosterone was measured by liquid chromatography-tandem mass spectrometry. Free testosterone was calculated from total testosterone and SHBG. RESULTS: Sixty-six women were included in the study. Total testosterone was associated with ovarian volume and antral follicle count but not with metabolic parameters. However, SHBG and calculated free testosterone were associated with both ovarian ultrasound and metabolic parameters, such as BMI and insulin resistance. CONCLUSIONS: Assessing SHBG and free testosterone is important in evaluating androgen excess in subfertile women with ovulatory dysfunction and suspected PCOS, as it reflects both ovarian and metabolic disturbances.

Comparison between the STENTYS self-apposing bare metal and paclitaxel-eluting coronary stents for the treatment of saphenous vein grafts (ADEPT trial).

AIMS: To describe the safety and performance of STENTYS self-expandable bare metal stents (BMS) versus paclitaxel-eluting stents (PES) in saphenous vein grafts (SVGs). METHODS AND RESULTS: A randomised controlled trial was performed in four hospitals in three European countries between December 2011 and December 2013. Patients with de novo lesions (>50% stenosis) in an SVG with a diameter between 2.5-6 mm were included. Primary endpoint was late lumen loss at 6 months. Secondary endpoints included procedural success and the occurrence of major adverse cardiac events (MACE) at 12 months. A total of 57 patients were randomised to STENTYS self-apposing BMS (n = 27) or PES (n = 30). Procedural success was obtained in 89.5%. No significant differences in late lumen loss were found between BMS and PES at 6 months (0.53 mm vs 0.47; p = 0.86). MACE rates at 12 months were comparable in both groups (BMS 22.2% vs. PES 26.7%; p = 0.70). CONCLUSIONS: Treatment of SVGs with STENTYS self-expandable stents is safe and effective. No significant differences were found in late lumen loss and MACE between BMS and PES.

Evaluation of the Sebia Minicap Flex Piercing capillary electrophoresis for hemoglobinopathy testing.

INTRODUCTION: Capillary zone electrophoresis (CZE) at alkaline pH is one of the techniques used for hemoglobinopathy screening. In this study, an evaluation of the performance of a lower throughput CZE instrument, the Sebia Minicap Flex Piercing system, for this purpose is reported for the first time. METHODS: The analytical performance of the Sebia Minicap Flex Piercing system was evaluated. Furthermore, a method comparison between the Sebia Minicap Flex Piercing and two HPLC methods, that is, the Bio-Rad Variant Classic(™) and the Bio-Rad D-10(™) systems was performed by measuring samples with and without clinically relevant hemoglobin disorders. RESULTS: The analytical performance was acceptable for the determination of HbA, HbA2, HbS, and HbF, with an imprecision ≤2.0%. Method comparison showed a linear correlation for HbA2, HbF, and HbS measurements. Clinical concordance was acceptable when comparing CZE and HPLC. CONCLUSIONS: Lower throughput CZE using the Sebia Minicap Flex Piercing can be used for precise and accurate first line screening and follow-up of hemoglobinopathies.

Performance of qualitative urinary hCG assays.

Significant differences in the sensitivity of eight frequently used qualitative urine human chorionic gonadotropin (hCG) tests in Belgium were observed in this study. Although most manufacturers claimed to detect hCG levels as low as 25 mIU/ml, only two out of six tests for home use and one out of two tests for professional use only, achieved the claimed detection limit. According to a survey, we performed among 20 acute care hospitals, 80% of the surveyed hospitals claimed to use these types of hCG analysis in a diagnostic setting. Unsatisfactory performance of these point-of-care testing (POC) assays for urinary hCG could have major consequences in a hospital setting, exposing the early pregnant woman to harmful diagnostic and therapeutic procedures. Although qualitative urine hCG tests are rapid and convenient, determination of hCG in blood remains the gold standard for the diagnosis of pregnancy.

Use of an Amplatzer Device for Endoscopic Closure of a Large Bronchopleural Fistula following Lobectomy for a Stage I Squamous Cell Carcinoma.

Bronchopleural fistulas can occur as a rare but severe complication after pulmonary resection. Established guidelines for the proper treatment of patients with bronchopleural fistulas do not exist. Apart from attempts to close the fistula, emphasis is placed on preventive measures, early treatment with antibiotics, drainage of the empyema and aggressive nutritional and rehabilitative support. For inoperable patients, endoscopic procedures are the only therapeutic option. Unfortunately, large (>8 mm) or central bronchopleural fistulas are usually not suitable for such endoscopic management. Recently, some groups have published a few case reports about a novel technique for the endobronchial closure of bronchopleural fistulas, using an Amplatzer device, originally designed for transcatheter closure of cardiac septal defects. We applied the same technique as a life-saving treatment in a ventilated patient who was considered inoperable due to a high oxygen need. The operation was successful. The patient could be weaned from ventilation and was eventually discharged from the hospital to a rehabilitation facility several weeks after the insertion of the device. Until now, endoscopic techniques have only been useful for the treatment of small, peripheral, bronchopleural fistulas and even then only as a bridge to surgery in high-risk surgical patients. In this case report, we demonstrate that the use of an Amplatzer device can expand the importance of endoscopic techniques in the treatment of bronchopleural fistulas. An Amplatzer device, for endobronchial closure, can indeed be administered for large and central bronchopleural fistulas. Moreover, it can be considered as a definite alternative to surgery in inoperable patients.

Hepcidin as a biomarker for the diagnosis of iron metabolism disorders: a review.

INTRODUCTION: Hepcidin plays a key role in the regulation of plasma iron levels through inhibition of iron export from enterocytes and macrophages. Hepcidin is considered a promising marker in the investigation of iron status, especially in patients that still pose a diagnostic challenge, such as infants and patients with chronic (kidney) disease. OBJECTIVE: To critically review the current evidence for the diagnostic utility of hepcidin, including the (pre) analytical aspects in hepcidin determination. SUMMARY: (Pre)analytical aspects--Since it is doubtful that the prohormone prohepcidin is a relevant biomarker, only the mature peptide hepcidin should be measured. Determinations of serum hepcidin are preferable, as the value of urine concentrations is still unclear. Method harmonization is needed since hepcidin values vary widely between methods. Several (pre-) analytical issues remain unanswered. These barriers hamper the investigation into the diagnostic value of hepcidin. Diagnostic utility--Hepcidin is an acute-phase reactant. The diagnostic potential of hepcidin is controversial in the different settings of iron deficiency as evidence is contradictory (anaemia of chronic disease) or limited (infants). In the setting of haemochromatosis, it has been suggested that hepcidin could be useful to stratify molecular testing, or to optimize the frequency of phlebotomies, but this remains to be investigated.

Cefazolin plasma protein binding and its covariates in neonates.

Cefazolin (CFZ) is highly and saturably bound to human serum albumin (HSA) in adults. We aim to describe CFZ protein binding and its covariates in neonates. In neonates to whom intravenous CFZ (50 mg/kg) was administered prior to a surgical procedure, total and unbound CFZ plasma concentrations (mg/l) were determined at 0.5, 2, 4 and 8 h after CFZ administration. Linear and multiple regression analyses were used to document covariates of unbound CFZ fraction. The Wilcoxon signed-rank test was used for the paired analysis of unbound CFZ fractions. In 40 patients with a median weight of 2,767 (range 830-4,200) g and a postmenstrual age (PMA) of 39 (25-45) weeks, 131 samples were collected. The median unbound CFZ fraction was 0.39 (0.10-0.73). Linear regression of unbound CFZ fraction versus unbound CFZ plasma concentration (R (2) = 0.39) had a slope significantly different from zero (p < 0.001). In a multiple regression analysis, albuminaemia, total CFZ concentration, indirect bilirubinaemia and PMA resulted in an R (2) value of 0.496. The median unbound CFZ fraction at the peak concentration (0.46, range 0.28-0.69) was significantly higher compared to the trough level (0.36, range 0.17-0.73) (p < 0.001). The between- and within-patient saturability of CFZ plasma protein binding were documented in neonates. The median unbound CFZ fraction in neonates is higher than in adults and depends partly on albuminaemia, total CFZ concentration, indirect bilirubinaemia and PMA. Integration of CFZ protein binding in future pharmacokinetic/pharmacodynamic research is warranted in order to optimise neonatal CFZ dosing. We recommend protein binding assessment in the neonatal pharmacokinetic evaluation of highly protein-bound or clinically relevant drugs.

Fluoroquinolone-resistant E. coli in intestinal flora of patients undergoing transrectal ultrasound-guided prostate biopsy--should we reassess our practices for antibiotic prophylaxis?

Although the estimate of the incidence of sepsis following transrectal ultrasound-guided prostate biopsy (TRUSPB) is low, fluoroquinolone-resistant infections after prostate biopsy are being increasingly noted. This study was aimed at determining the prevalence of faecal carriage of fluoroquinolone-resistant Escherichia coli strains before TRUSPB and at evaluating potential predisposing risk factors. The incidence of sepsis after prostate biopsy was determined, and our routine practice for antibiotic prophylaxis for TRUSPB was evaluated. A prospective study was conducted in 342 consecutive patients undergoing prostate biopsy between December 2009 and July 2010. Before TRUSPB, a rectal swab was cultured. The correlation between the presence of fluoroquinolone-resistant strains and plausible risk factors was investigated by the use of a questionnaire. Of the 236 patients included, 22.0% (52/236) harboured ciprofloxacin-resistant E. coli strains. The use of fluoroquinolones in the 6 months before biopsy was associated with an increased risk of faecal carriage of fluoroquinolone-resistant E. coli strains (p <0.01). Faecal carriage of fluoroquinolone-resistant E. coli strains was an important risk factor for infectious complications after TRUSPB (p <0.01). In conclusion, a significant number of patients have faecal carriage of fluoroquinolone-resistant E. coli strains (22.0%) before TRUSPB. The use of fluoroquinolones in the previous 6 months before biopsy is a risk factor for faecal carriage of fluoroquinolone-resistant E. coli strains and for infectious complications after TRUSPB. Hence, the universal administration of fluoroquinolones should be reconsidered.

Pregnancy during nitisinone treatment for tyrosinaemia type I: first human experience.

A 19 year old woman with tyrosinaemia type 1 gave birth to a healthy girl after 41 weeks of gestation. Nitisinone was continued throughout the pregnancy (maternal levels 68-96 µmol/l, target level 30-60 µmol/l). Tyrosine levels during pregnancy were between 500 and 693 µmol/l (normal values 20-120 µmol/l) and phenylalanine levels between 8 and 39 µmol/l (normal values 30-100 µmol/l). Nitisinone was measurable in neonatal blood immediately after birth, at a level comparable to the simultaneous level in the mother. Nitisinone half-life in the neonate was estimated to be 90 h. Tyrosine levels in the neonate decreased from 1,157 µmol/l at birth (cord blood) to normal levels within 4 weeks. Phenylalanine levels in the neonate were normal from birth on. The child had a normal psychomotor development as assessed throughout the first year of life.This is the first report worldwide of a pregnancy during treatment with nitisinone.In this case, no adverse effects of nitisinone, maternal high tyrosine or low phenylalanine were detected in the child, so far. Long-term results in a larger cohort of pregnancies and births are needed to determine whether nitisinone can be administered safely during pregnancy.

Evaluation of the use of a combined HCV antigen/antibody assay in routine laboratory practice.

BACKGROUND: Combined hepatitis C virus (HCV) antigen/antibody (Ag/Ab) assays offer the advantage of a shorter window phase compared to traditional anti-HCV antibody assays. These assays have been extensively evaluated for the screening of healthy blood donors, but not in routine laboratory practice. METHODS: We evaluated the performance of the combined HCV Ag/Ab assay Monolisa Ultra and compared it to Monolisa anti-HCV Plus (which only detects anti-HCV antibodies) in 61 HCV RNA-positive patients (genotypes 1 to 5) and in 276 consecutive AxSYM HCV-reactive patients. Discordant sera were tested with immunoblot and PCR. RESULTS: All 61 PCR-positive sera were positive with AxSYM, Monolisa Ultra, and Monolisa Plus. Of the 276 consecutive AxSYM-reactive patients, 177 were confirmed as HCV-positive, 78 were HCV-negative and 21 were HCV-indeterminate. There were 4 false-positive results with Monolisa Ultra compared to 1 false-positive result with Monolisa PLus. The signal/cut-off ratio in immunoblot-negative sera was significantly higher with HCV Ultra compared to HCV Plus (p < 0.01). Sensitivity and specificity in AxSYM-reactive sera were 99.4% and 94.9% for Monolisa Ultra and 99.4% and 98.7% for Monolisa Plus. CONCLUSION: When used as a secondary test, the sensitivity of the combined HCV Ag/Ab assay Monolisa Ultra was excellent, but specificity was reduced in AxSYM-reactive sera compared to Monolisa Plus.

Anti-PM/Scl-100 and anti-RNA-polymerase III antibodies in scleroderma.

BACKGROUND: Systemic sclerosis (SSc) is a rare autoimmune disease characterized by the presence of various autoantibodies, including anti-centromere, anti-topoisomerase (Scl-70), anti-PM/Scl-100, and anti-RNA-polymerase III (RNA Pol-III) antibodies. Recently, new ELISA based immunoassays have become available for the detection of anti-PM/Scl and anti-RNA Pol-lII antibodies. OBJECTIVE: We studied the prevalence and clinical association of anti-PM/Scl-100 (PM1-Alpha) and anti-RNA Pol-III antibodies. METHODS: Antibodies to PM1-Alpha and RNA Pol-III were measured by ELISA (DR. Fooke Laboratories and Inova Diagnostics, respectively) in 242 patients with various connective tissue diseases (CTD) (including 70 SSc patients) and in 36 non-CTD controls. RESULTS: Low levels of PM1-Alpha antibodies were found in various CTDs, whereas high levels were exclusively found in SSc, dermatomyositis and polymyositis, albeit at low frequency (4.7%). Anti-RNA Pol-III antibodies were found in 7% of SSc and in 1% of non-CTD and CTD controls. Anti-centromere and anti-Scl-70 antibodies were found in 37% and 21% of SSc patients, respectively. Anti-centromere antibodies were associated with limited cutaneous SSc and anti-Scl-70 antibodies with diffuse cutaneous SSc and interstitial lung disease. Because of the low number of samples positive for anti-PM/Scl-100 or RNA Pol-III antibodies, no clinical feature was statistically correlated with the presence of either reactivity, but taken together the presence of either antibody was correlated with interstitial lung disease. Anti-PM1-Alpha and anti-RNA Pol-III antibodies were mutually exclusive with anti-Scl-70 antibodies. CONCLUSIONS: At high levels, anti-PM/Scl-100 antibodies were associated with SSc, PM, and DM, albeit at low frequency. Anti-RNA Pol-III antibodies were associated with SSc (in 7%) with high specificity.

Localization, etiology and impact of calcium phosphate deposits in renal allografts.

Hypercalcemia, hypophosphatemia and renal phosphate wasting are common after kidney transplantation. Animal data suggest that these alterations in mineral metabolism may contribute to calcium phosphate (CaPhos) deposition in the kidney and renal dysfunction. We tested the hypothesis that CaPhos deposition is highly prevalent in the early posttransplant period and is related to a disturbed mineral metabolism. For this purpose, biomarkers of mineral metabolism and renal calcium and phosphorus handling were prospectively assessed in 201 renal transplant recipients. CaPhos deposits were observed in 4.6, 30.4 and 24.7% of protocol biopsies obtained at the time of engraftment, and 3 and 12 months thereafter, respectively. In multivariate logistic regression analysis, high calcium and low serum phosphorus levels were independently associated with renal CaPhos deposition at month 3. The extent of CaPhos deposition correlated significantly with the severity of mineral metabolism disturbances. Renal function after a mean follow-up of 33 months was similar in patients with and without CaPhos deposition at month 3. In conclusion, our data demonstrate that CaPhos deposition is highly prevalent in the early posttransplant period and suggest that a disordered mineral metabolism is implicated in its pathogenesis. The clinical relevance of CaPhos deposition remains to be established.

Co-inheritance of haemoglobin A2' and beta-thalassaemia in cis.

HbA2' is a haematologically silent delta chain variant that elutes in the S-region on high performance liquid chromatography. The major clinical significance of HbA2' is that failure to detect it might lead to failure to recognize beta-thalassaemia minor. Co-inheritance of HbA2' and beta-thalassaemia in cis has been described only once in a family from Suriname. We describe a new case of co-inheritance in cis of HbA2' and beta-thalassaemia in a family from Ghanaian origin with a HbA2' of more than 3%. Molecular investigation revealed the same mutations as in the family from Suriname, suggesting a common origin of both families.