Optimizing pulse compressibility in completely all-fibered Ytterbium chirped pulse amplifiers for in vivo two photon laser scanning microscopy

A simple and completely all-fiber Yb chirped pulse amplifier that uses a dispersion matched fiber stretcher and a spliced-on hollow core photonic bandgap fiber compressor is applied in nonlinear optical microscopy. This stretching-compression approach improves compressibility and helps to maximize the fluorescence signal in two-photon laser scanning microscopy as compared with approaches that use standard single mode fibers as stretcher. We also show that in femtosecond all-fiber systems, compensation of higher order dispersion terms is relevant even for pulses with relatively narrow bandwidths for applications relying on nonlinear optical effects. The completely all-fiber system was applied to image green fluorescent beads, a stained lily-of-the-valley root and rat-tail tendon. We also demonstrated in vivo imaging in zebrafish larvae, where we simultaneously measure second harmonic and fluorescence from two-photon excited red-fluorescent protein. Since the pulses are compressed in a fiber, this source is especially suited for upgrading existing laser scanning (confocal) microscopes with multiphoton imaging capabilities in space restricted settings or for incorporation in endoscope-based microscopy.

Green-Light-Induced Inactivation of Receptor Signaling Using Cobalamin-Binding Domains

Optogenetics and photopharmacology provide spatiotemporally precise control over protein interactions and protein function in cells and animals. Optogenetic methods that are sensitive to green light and can be used to break protein complexes are not broadly available but would enable multichromatic experiments with previously inaccessible biological targets. Herein, we repurposed cobalamin (vitamin B12) binding domains of bacterial CarH transcription factors for green-light-induced receptor dissociation. In cultured cells, we observed oligomerization-induced cell signaling for the fibroblast growth factor receptor 1 fused to cobalamin-binding domains in the dark that was rapidly eliminated upon illumination. In zebrafish embryos expressing fusion receptors, green light endowed control over aberrant fibroblast growth factor signaling during development. Green-light-induced domain dissociation and light-inactivated receptors will critically expand the optogenetic toolbox for control of biological processes.

The proteome pattern cGvHD_MS14 allows early and accurate prediction of chronic GvHD after allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) may be curative, but is associated with significant morbidity and mortality. Chronic graft-versus-host disease (cGvHD), characterized by inflammation and fibrosis of multiple target organs, considerably contributes to the morbidity and mortality even years after allo-HSCT. Diagnosis of cGvHD is based on clinical features and histology of biopsies. Here, we report the generation of a urinary cGvHD-specific proteome-pattern (cGvHD_MS14) established by capillary electrophoresis-mass spectrometry to predict onset and severity of cGvHD as an unbiased laboratory test. cGvHD_MS14 was evaluated on samples from 412 patients collected prospectively in four transplant centers. Sensitivity and specificity was 84 and 76% by cGvHD_MS14 classification. Sensitivity further increased to 93% by combination of cGvHD_MS14 with relevant clinical variables to a logistic regression model. cGvHD was predicted up to 55 days prior to clinical diagnosis. Acute GvHD is not recognized by cGvHD_MS14. cGvHD_MS14 consists of 14 differentially excreted peptides, six of those have been sequenced to date and are fragments from thymosin β-4, eukaryotic translation initiation factor 4γ2, fibrinogen β-chain or collagens. In conclusion, the cGvHD_MS14-pattern allows early, highly sensitive and specific prediction of cGvHD as an independent diagnostic criterion of clinical diagnosis potentially allowing early therapeutic intervention.

Prevalence and comorbidities of double diabetes

BACKGROUND

A growing number of people with type 1 diabetes (T1DM) are identified with features of metabolic syndrome (MS) known as "double diabetes", but epidemiologic data on the prevalence of MS in T1DM and its comorbidities are still lacking. Aim of this cross sectional study is to better estimate the prevalence of MS in T1DM, and to assess its association with comorbidities.

METHODS

Data of 31,119 persons with autoimmune diabetes mellitus were analysed for signs of MS and presence of late complications. Double diabetes was defined as T1DM coexisting with MS (obesity, hypertension, dyslipidemia). Multiple linear or logistic regression analyses were performed to identify associations between double diabetes and late complications.

RESULTS

25.5% (n=7926) of persons with T1DM presented additionally the MS. Persons with double diabetes showed significantly more macrovascular comorbidities (coronary heart disease 8.0% versus 3.0% w/o MS, stroke 3.6% versus 1.6%, diabetic foot syndrome 5.5% versus 2.1%). Also microvascular diseases were increased in people with double diabetes (retinopathy 32.4% versus 21.7%, nephropathy 28.3% versus 17.8%). Both macrovascular and microvascular comorbidities were increased independent of glucose control, even if patients with good metabolic control (HbA1c <7.0%, 53mmol/mol) showed significantly less macrovascular (coronary heart disease 2.3% versus 1.8%, p<0.0001) and microvascular problems (retinopathy 8.7% versus 6.6%, p<0.0001).

CONCLUSIONS

Double diabetes seems to be an independent and important risk factor for persons with T1DM in developing macrovascular and microvascular comorbidities. Therefore, patients should be identified and development of MS should be avoided. Longterm studies are needed to observe the effect of insulin resistance on patients with autoimmune diabetes.

Identification of the putative binding pocket of valerenic acid on GABAA receptors using docking studies and site-directed mutagenesis

Background and Purpose

β2/3‐subunit‐selective modulation of GABA_A receptors by valerenic acid (VA) is determined by the presence of transmembrane residue β2/3N265. Currently, it is not known whether β2/3N265 is part of VA's binding pocket or is involved in the transduction pathway of VA's action. The aim of this study was to clarify the localization of VA's binding pocket on GABA_A receptors.

Experimental Approach

Docking and a structure‐based three‐dimensional pharmacophore were employed to identify candidate amino acid residues that are likely to interact with VA. Selected amino acid residues were mutated, and VA‐induced modulation of the resulting GABA_A receptors expressed in Xenopus oocytes was analysed.

Key Results

A binding pocket for VA at the β⁺/α⁻ interface encompassing amino acid β3N265 was predicted. Mutational analysis of suggested amino acid residues revealed a complete loss of VA's activity on β3M286W channels as well as significantly decreased efficacy and potency of VA on β3N265S and β3F289S receptors. In addition, reduced efficacy of VA‐induced I_GABA enhancement was also observed for α1M235W, β3R269A and β3M286A constructs.

Conclusions and Implications

Our data suggest that amino acid residues β3N265, β3F289, β3M286, β3R269 in the β3 subunit, at or near the etomidate/propofol binding site(s), form part of a VA binding pocket. The identification of the binding pocket for VA is essential for elucidating its pharmacological effects and might also help to develop new selective GABA_A receptor ligands.

Comparison of several von Willebrand factor (VWF) activity assays for monitoring patients undergoing treatment with VWF/FVIII concentrates: improved performance with a new modified automated method

BACKGROUND

The ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy.

OBJECTIVE

We assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS(®) ) compared to other available assay methods.

METHODS

Results from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0-1.2 IU mL(-1) ). Samples were prepared by mixing VWF concentrate or plasma standard into VWF-depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements.

RESULTS

In the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility.

CONCLUSIONS

A modified BCS(®) VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS(®) assay displayed good precision. This study indicates that the specific modifications - namely the combination of increased ristocetin concentration, reduced platelet content, VWF-depleted plasma as on-board diluent and a two-curve calculation mode - reduces the issues seen with current VWF:RCo activity assays.

Unsupervised home use of an overnight closed-loop system over 3-4 weeks: a pooled analysis of randomized controlled studies in adults and adolescents with type 1 diabetes

AIMS

To compare overnight closed-loop and sensor-augmented pump therapy in patients with type 1 diabetes by combining data collected during free-living unsupervised randomized crossover home studies.

METHODS

A total of 40 participants with type 1 diabetes, of whom 24 were adults [mean ± standard deviation (s.d.) age 43 ± 12 years and glycated haemoglobin (HbA1c) 8.0 ± 0.9%] and 16 were adolescents (mean ± s.d. age 15.6 ± 3.6 years and HbA1c 8.1 ± 0.8%), underwent two periods of sensor-augmented pump therapy in the home setting, in combination with or without an overnight closed-loop insulin delivery system that uses a model predictive control algorithm to direct insulin delivery. The order of the two interventions was random; each period lasted 4 weeks in adults and 3 weeks in adolescents. The primary outcome was time during which sensor glucose readings were in the target range of 3.9-8.0 mmol/l.

RESULTS

The proportion of time when sensor glucose was in the target range (3.9-8.0 mmol/l) overnight (between 24:00 and 08:00 hours) was 18.5% greater during closed-loop insulin delivery than during sensor-augmented therapy (p < 0.001). Closed-loop therapy significantly reduced mean overnight glucose levels by 0.9 mmol/l (p < 0.001), with no difference in glycaemic variability, as measured by the standard deviation of sensor glucose. Time spent above the target range was reduced (p = 0.001), as was time spent in hypoglycaemia (<3.9 mmol/l; p = 0.014) during closed-loop therapy. Lower mean overnight glucose levels during closed-loop therapy were brought about by increased overnight insulin delivery (p < 0.001) without changes to the total daily delivery (p = 0.84).

CONCLUSION

Overnight closed-loop insulin therapy at home in adults and adolescents with type 1 diabetes is feasible, showing improvements in glucose control and reducing the risk of nocturnal hypoglycaemia.

Treatment of rare co-occurrence of Epstein-Barr virus-driven post-transplant lymphoproliferative disorder and hemophagocytic lymphohistiocytosis after allogeneic stem cell transplantation

In both conditions, post-transplant lymphoproliferative disorder (PTLD) and hemophagocytic lymphohistiocytosis (HLH), infection with Epstein-Barr virus (EBV) is a key mechanism: almost all PTLD in allogeneic stem cell transplantation (alloSCT) is caused by EBV-related neoplastic lymphoproliferation, and secondary HLH is most frequently triggered by EBV infection. Therefore, concomitant EBV-driven PTLD and HLH early after alloSCT require an approach to eliminate EBV and balance immune activation simultaneously. We report on a patient who developed simultaneous PTLD and signs of HLH on day 64 after alloSCT. Treatment was comprised of stopping cyclosporine, short-course dexamethasone, and 3 courses of rituximab. The patient showed full recovery and complete remission of lymphadenopathy. This result indicates that immediate reduction in EBV-carrying B cells by rituximab, suppression of general inflammation, and parallel support of reconstitution of long-term T-cell function, might be an appropriate therapeutic approach in this rare situation.

Über Metalltrifluorphosphin-Komplexe XXII. Substitutions-Reaktionen von Tetrakis(trifluorphosphin)-nickel(O) mit Donatorverbindungen von Elementen der 5. Hauptgruppe

Bei Umsetzungen von Tetrakis (trifluorphosphin) -nickel (O) mit N-Donatoren können nur mit zweizähligen Stickstoffliganden (L2 = 2.2′-Dipyridyl, 1.10-Phenanthrolin) isolierbare Derivate erhalten werden, nämlich die kristallinen, orangeroten und in Lösung instabilen Disubstitutionsprodukte Ni (PF3) 2L2. Hingegen gelangt man mit den einzähligen Donatoren E (C6H5)3 (E = P, As, Sb) zu farblosen und auch in Lösung stabilen, kristallinen Substitutionsverbindungen Ni (PF3) 4 - n [E (C6H5)3]n (n = 1 und 2). Ein schrittweiser Ersatz der Phenylgruppen im P (C6H5) 3 gegen Chlor läßt Tri- [P (CeH5) 2Cl] und Tetrasubstitution [P (CeH5) Cl2, PCl3] zu. Die Verbindungen werden an Hand ihrer IR- und Massenspektren charakterisiert. Vollständige massenspektrometrische Abbaumechanismen können nur vom Nickeltrifluorphosphin und seinen Monosubstitutions-Produkten aufgestellt werden. Die Abstufung des Donatorvermögens der Substituenten wird IR-spektroskopisch aufgezeigt.

Fasting and postprandial liver glycogen content in patients with type 1 diabetes mellitus after successful pancreas-kidney transplantation with systemic venous insulin delivery

BACKGROUND

In patients with type 1 diabetes mellitus (T1DM), insulin is usually replaced systemically (subcutaneously) and not via the physiological portal route. According to previous studies, the liver's capacity to store glycogen is reduced in T1DM patients, but it remains unclear whether this is due to hyperglycaemia, or whether the route of insulin supply could contribute to this phenomenon. T1DM patients after successful pancreas-kidney transplantation with systemic venous drainage (T1DM-PKT) represent a suitable human model to further investigate this question, because they are normoglycaemic, but their liver receives insulin from the pancreas transplant via the systemic route.

MATERIALS AND METHODS

In nine T1DM-PKT, nine controls without diabetes (CON) and seven patients with T1DM (T1DM), liver glycogen content was measured at fasting and after two standardized meals employing (13) C-nuclear-magnetic-resonance-spectroscopy. Circulating glucose and glucoregulatory hormones were measured repeatedly throughout the study day.

RESULTS

The mean and fasting concentrations of peripheral plasma glucose, insulin, glucagon and C-peptide were comparable between T1DM-PKT and CON, whereas T1DM were hyperglycaemic and hyperinsulinaemic (P < 0·05 vs T1DM-PKT and CON). Total liver glycogen content at fasting and after breakfast did not differ in the three groups. After lunch, T1DM-PKT and T1DM had a 14% and 21% lower total liver glycogen content than CON (P < 0·02).

CONCLUSION

In spite of normalized glycaemic control, postprandial liver glycogen content was reduced in T1DM-PKT with systemic venous drainage. Thus, not even optimized systemic insulin substitution is able to resolve the defect in postprandial liver glycogen storage seen in T1DM patients.

Is there a benefit to use calculated percent body fat or age- and gender-adjusted BMI-SDS(LMS) to predict risk factors for cardiovascular disease? A German/Austrian multicenter DPV-Wiss analysis on 42 048 type 2 diabetic patients

OBJECTIVE

In clinical practice Body Mass Index is generally used to evaluate overweight status in adults. The present multicenter study examines whether Body Mass Index (BMI), age- and gender-adjusted Body Mass Index Standard Deviation Score, or calculated %body fat is a better predictor for cardiovascular disease risk factors, specifically hypertension and dyslipidemia, in a high-risk population.

METHODS

Data of 42 048 adult type 2 diabetic patients (median age: 67.1 years) from 161 centers in Germany (n=158) and Austria (n=3) registered in a standardized, prospective, computer-based documentation program, were included in the study. For each patient body weight, height, blood pressure and blood lipids were documented. Spearman correlation analyses as well as multivariable logistic regression models were used to examine the relationship between anthropometric measurements and cardiovascular disease risk factors.

RESULTS

Correlation and regression analyses revealed minor, non significant differences between the 3 anthropometric measurements (all p>0.05). In both genders, relationships between anthropometric measurements and hypertension or reduced HDL-cholesterol were nearly identical. Only for increased triglycerides, the relations with the 3 anthropometric measurements were significantly stronger in males than in females (p<0.0001, respectively). With increasing age, associations between anthropometric measurements and hypertension, reduced HDL-cholesterol or increased triglycerides became weaker. Spearman correlation coefficients for total cholesterol and LDL-cholesterol revealed weak associations with the 3 anthropometric measurements.

CONCLUSION

Compared to Body Mass Index, age- and gender-adjusted Body Mass Index Standard Deviation Score, or calculation of %body fat, has no further benefit to predict cardiovascular disease risk factors in adult type 2 diabetic patients.

Renal comorbidity after solid organ and stem cell transplantation

After transplantation of solid organs or hematopoietic stem cells, a significant acute decrease in renal function occurs in the majority of patients. Depending on the degree of kidney injury, a large number of patients develop chronic kidney disease (CKD) and some develop end-stage renal disease requiring renal replacement therapy. The incidence varies depending on the transplanted organ, but important risk factors for the development of CKD are preexisting renal disease, hepatitis C, diabetes, hypertension, age, sex, posttransplant acute kidney injury and thrombotic microangiopathy. This review article focuses on the risk factors of posttransplant chronic kidney disease after organ transplantation, considering the current literature and integrates the incidence and the associated mortality rates of acute and chronic kidney disease. Furthermore, we introduce the RECAST (REnal Comorbidity After Solid organ and hematopoietic stem cell Transplantation) registry.

Outcomes and prognostic factors of adults with acute lymphoblastic leukemia who relapse after allogeneic hematopoietic cell transplantation. An analysis on behalf of the Acute Leukemia Working Party of EBMT

To describe outcomes, treatment and prognostic factors that influence survival of adult patients with acute lymphoblastic leukemia (ALL), who relapsed after allogeneic hematopoietic cell transplantation (HCT), we retrospectively analyzed 465 ALL adult patients from European Group for Blood and Marrow Transplantation (EBMT) centers who relapsed after a first HCT performed in complete remission (CR1 65%, CR2/3 35%). Salvage treatments were: supportive care (13%), cytoreductive therapy (43%), donor lymphocyte infusion without or with prior chemotherapy (23%) and second HCT (20%). Median time from HCT to relapse was 6.9 months, median follow-up was 46 months and median survival after relapse was 5.5 months. Estimated 1-, 2- and 5-year post-relapse survival was 30 ± 2%, 16 ± 2% and 8 ± 1%, respectively. In a multivariate analysis, adverse factors for survival were: late CR (CR2/3) at transplant (P<0.012), early relapse after transplant (<6.9 months, P <0.0001) and peripheral blast percent at relapse (P <0.0001). On the basis of multivariate model for survival, three groups of patients were identified with estimated 2 year survival of 6 ± 2, 17 ± 3 and 30 ± 7%. Outcome of ALL patients relapsing after HCT is dismal and there is a need for new therapies. Our study provides the standard expectations in ALL relapse and may help in the decision of post-relapse therapy.

Tetramer monitoring to assess risk factors for recurrent cytomegalovirus reactivation and reconstitution of antiviral immunity post allogeneic hematopoietic stem cell transplantation

BACKGROUND

Reactivation of cytomegalovirus (CMV) is a major cause of morbidity after allogeneic hematopoietic stem cell transplantation (HSCT). In healthy individuals, virus-specific T cells (CMV-CTL) control the reactivation of latent CMV. The monitoring of virus-epitope-binding CD8(+) T cells using major histocompatibility complex-I-peptide complexes (tetramers) has recently been established, allowing assessment of the reconstitution of CMV-CTL post HSCT.

PATIENTS AND METHODS

In order to study immune reconstitution and reactivation control through CMV-CTL, we regularly monitored all patients undergoing allogeneic HSCT in our department for 2 years, who matched at least 1 of 6 commercially available tetramers for common human leukocyte antigen (HLA) types. To verify risk factors for CMV reactivations in our cohorts, clinical characteristics of all patients transplanted within the last 10 years were included in statistical analyses determining the relative risk for single and recurrent CMV reactivations.

RESULTS

As expected, CMV serostatus, HLA match, and donor source significantly influenced the risk of recurrent CMV reactivation. Applying CMV-CTL tetramer monitoring for 2 years allowed the monitoring of 114 (85%) of 134 patients, by testing a set of tetramers representing 6 epitopes from 3 different CMV proteins. The presence of CMV-CTL before day + 50 and their expansion post reactivation seem to protect against recurrent CMV reactivations. The mean number of CMV-CTL by day +100 was >5-fold higher in the recipient CMV-positive/donor-positive (R +/D +) group (91/μL) compared with the R +/ D- (13/μL) and the R -/D +(2/μL) group. Seventy-nine percent of patients from the R +/D + setting recovered >10 CMV-CTL per μL by day + 100, while almost 50% of the other groups failed to mount a CMV-specific response by that time (R +/D -: 58%; R -/D +: 43%).

CONCLUSION

Tetramer monitoring can help to predict (recurrent) CMV reactivation and is a useful approach to monitor individual patients with increased risk for recurrent reactivation post HSCT; thus, it could help to identify patients in need of adoptive transfer of CMV-CTL or to optimize the use of antiviral drugs.