Hypophosphorylated TCR/CD3zeta signals through a Grb2-SOS1-Ras pathway in Lck knockdown cells

Despite the loss of proximal TCR-dependent signaling events, downstream T cell responses are paradoxically augmented in T cells with siRNA-mediated Lck knockdown (Methi et al., J. Immunol. 2005. 175: 7398-7406). This indicates that alternative Lck-independent pathways of T cell activation exist or that low levels of Lck elicit other signals than normal T cell activation. Here we report the recruitment of Grb2-SOS1 to CD3zeta of the TCR complex after prolonged anti-CD3 (OKT3) stimulation in T cells with Lck knockdown. Grb2 bound to incompletely phosphorylated ITAM1 with the pY-Y configuration in a solid-phase assay, but was excluded by ZAP-70 in the doubly phosphorylated pY-pY conformation. Ras and ERK1/2 activation was augmented after prolonged stimulation in T cells with Lck knockdown compared to control, leading to increased activation of the proximal IL-2 promoter (NFAT-AP-1). Finally, the phosphorylation of Ras-GAP was strongly suppressed in Lck knockdown cells, indicating that a Ras negative feedback mechanism is dependent on Lck.     

Statins and Angiotensin‐Converting Enzyme Inhibitors are Associated with Reduced Mortality and Morbidity in Chronic Liver Disease

Liver fibrosis is a common response to many chronic liver diseases. The aim of our study was to explore whether pharmacotherapy for concurrent diseases affects overall mortality, liver‐related mortality and liver‐related morbidity in patients with chronic liver disease. We performed a register‐based cohort study of all patients with a first‐time diagnosis of chronic liver disease between 2005 and 2012 in Sweden (n = 70 546). Data from the Patient Register, the Prescribed Drug Register and the Death Certificate Register were linked . We studied whether the use of statins, angiotensin‐converting enzyme inhibitors, angiotensin receptor blockers and antibiotics affected the risk of total mortality, liver‐specific mortality and morbidity. We found a reduction in mortality risk for statin users (n = 11,245) with hazard ratios from 0.57 (95% CI: 0.32–0.99) for patients with autoimmune hepatitis to 0.84 (95% CI: 0.75–0.95) for patients with alcoholic liver disease. There was a significantly reduced liver‐related mortality for patients with alcoholic liver disease who used angiotensin‐converting enzyme inhibitors, 0.85 (95% CI: 0.65–0.96). There were increased overall mortality risks for antibiotic users (n = 44,572), with hazard ratios up to 1.67 (95% CI, 1.55–1.80) for viral hepatitis. Statin use was associated with decreased risks of liver‐specific mortality and morbidity, and reduced total mortality foremost among patients with alcoholic liver disease. Angiotensin ‐converting enzyme inhibitors was associated with reduced liver‐related mortality among patients with alcoholic liver disease.     

Effect of reverse total shoulder arthroplasty humeral inclination on glenohumeral range of motion,deltoid force,and glenoid strain: a biomechanical study

BackgroundReverse total shoulder arthroplasty (RSA) primarily varies between 2 implant design options: a 135 humeral stem inclination that closely resembles anatomic orientation, versus the Grammont-style 155 humeral stem inclination that further medializes and distalizes the center of rotation (COR). The purpose of this study was to compare deltoid force, glenoid strain, and simulated glenohumeral range of motion (ROM) between RSA 135 and RSA 155 designs, with a series of standardized permutations of glenosphere offset and rotator cuff pathology.MethodsTwelve fresh-frozen cadaveric shoulder specimens were studied using a shoulder simulator. Native shoulder motion profiles for reproducible abduction range of motion were established using a customized testing device. Optical 3-dimensional tracking and pressure sensors were used to accurately record glenohumeral range of motion (ROM), deltoid force, and glenoid strain for RSA 135 and RSA 155 designs. For each cohort, all combinations of glenosphere offsets and rotator cuff tendon involvement were evaluated.ResultsThere was no significant difference in the overall abduction ROM between the 155 and the 135 humeral stem implants (P = .75). Resting abduction angle and maximum abduction angle were significantly greater with a 155 + STD (standard offset) construct than with a 135 + STD construct (P < .001 and P = .01, respectively). Both stem inclinations decreased combined deltoid force requirements as compared the native shoulder with a massive cuff tear. Effective glenoid strain did not vary significantly between 135 + STD and 155 + STD constructs (P = .66).ConclusionOverall, range of motion between the 135 and the 155 humeral stem inclinations was not significantly different. The cumulative deltoid force was lower in RSA shoulders when compared to native shoulders with massive rotator cuff tears, highlighting the utility of both implant designs. The Grammont-style 155 stem coupled with a 2.5 mm inferior offset glenosphere required less deltoid force to reach maximum abduction than did the more anatomic, lateralized 135 stem coupled with a 4 mm lateral offset glenosphere.Level of EvidenceBasic Science, Biomechanics Controlled Laboratory Study     

Flexions- und Extensionsosteotomien der proximalen Tibia

Background

Isolated deviations in flexion and extension of the leg axis are rare. These deviations can be corrected if necessary by osteotomy and the range of motion (ROM) of the knee joint can be optimized. In addition to correction in the frontal plane, the tibial slope (i.e. inclination of the surface of the tibial joint) can also be influenced by osteotomy and therefore osteotomy can also be utilized to optimize the biomechanical stability of the knee joint.

Method

Careful planning taking all three spatial planes and torsion into consideration is the foundation of a successful operation. A controlled surgical technique based on careful planning and some basic principles allows the alteration of the three dimensional alignment of the tibia.     

Psychotropic medication in geriatric psychiatric patients: use and unreported use in relation to serum concentrations

Purpose

The aim of this observational study was to describe the type, number, and serum concentration levels of psychotropic drugs in elderly patients, on admission to a geriatric psychiatric inpatient unit. We further wanted to investigate the use and unreported use of psychotropic drugs by analyzing for a broad spectrum of drugs in the serum samples.

Methods

A total of 236 patients were included. Drug use, patient characteristics, and diagnoses were recorded, and serum analysis was performed for a total of 56 psychotropic drugs in 233 of the patients.

Results

Nine out of ten patients (88 %) used one or more psychotropic drugs on admission to hospital; the mean use was 2.8 (95 % confidence interval (CI) 2.6–2.9) drugs. In 25 patients (11 %), drugs reported used were not detected in serum. Unreported use of drugs (serum analysis revealing one or more drugs not reported) was found in 100 patients (43 %). This was more common in younger patients. Psychotropic polypharmacy (use of three or more psychotropic drugs) was found in 109 patients (47 %). Patients with a main diagnosis of affective disorder used the most psychotropic drugs.

Conclusions

Psychotropic drugs are commonly used among geriatric psychiatric patients on admission to hospital. Psychotropic polypharmacy is a major concern among these patients. There was considerable unreported use of drugs within this population, and a low threshold for a broader serum analysis for psychotropic drugs appears indicated.     

Heart transplantation for end-stage heart failure caused by iron overload

Few reports exist concerning heart transplantation in recipients with end-stage myocardiopathy-associated heart failure caused by iron overload occurring with β-thalassaemia, Diamond-Blackfan syndrome or haemochromatosis. Seven potential transplant candidates (six male, one female, mean age 26 years) with such heart failure, following desferrioxamine application subcutaneously over a number of years, and intravenously during their hospitalization before transplantation, were retrospectively analysed. Five were New York Heart Association (NYHA) class IV, three experienced one or more resuscitations immediately before transplantation could be performed. Continuous, high-volume, veno-venous haemofiltration was necessary in two patients. One of these two candidates additionally had to be bridged, first with a right ventricular, then with a biventricular assist device. Five of the seven patients survived, two with haemochromatosis, one with β-thalassaemia major and one with Diamond-Blackfan syndrome following transplantation. One non-transplanted candidate with β-thalassaemia major has been recompensated for 5 years. Survival was 14–74 months. Our results demonstrate the feasibility and indication of transplantation in patients with such heart failure and the satisfying outcome of immunosuppression is described.     

Transcapillary fluid balance in immature rats. Interstitial fluid pressure,serum and interstitial protein concentration,and colloid osmotic pressure

Several of the factors governing transcapillary fluid balance were studied in anesthetized rats from the age of 1 to 60 days. Serum albumin and total protein concentrations rose from 1.7 and 2.4 g/100 ml at birth to 4.1 and 6.2 g/100 ml in adult rats, while colloid osmotic pressure rose from 5.3 to about 20 mm Hg. Interstitial fluid collected from subcutis by the wick technique showed protein concentrations of approximately 60% of serum values in all age groups, and its colloid osmotic pressure rose from about 3 to 10 mm Hg during maturation. Arterial pressure rose from about 50 mm Hg in newborn rats to 120 mm Hg in adult animals. Iliac venous pressure was only 0.5–1 mm Hg in 10-day-old rats compared to 3 mm Hg in adult animals. Interstitial fluid pressures of 0 to ?1 mm Hg were obtained in all age groups with the “wick-in-needle” technique. The data suggest an average capillary pressure of less than 5 mm Hg in newborn animals and a pre- to postcapillary resistance ratio similar to that of adult animals. The safety factors against edema formation seem to be small in immature rats.     

GCK-MODY diabetes as a protein misfolding disease: The mutation R275C promotes protein misfolding,self-association and cellular degradation

GCK-MODY, dominantly inherited mild hyperglycemia, is associated with more than 600 mutations in the glucokinase gene. Different molecular mechanisms have been shown to explain GCK-MODY. Here, we report a Pakistani family harboring the glucokinase mutation c.823C > T (p.R275C). The recombinant and in cellulo expressed mutant pancreatic enzyme revealed slightly increased enzyme activity (k_cat) and normal affinity for α-D-glucose, and resistance to limited proteolysis by trypsin comparable with wild-type. When stably expressed in HEK293 cells and MIN6 β-cells (at different levels), the mutant protein appeared misfolded and unstable with a propensity to form dimers and aggregates. Its degradation rate was increased, involving the lysosomal and proteasomal quality control systems. On mutation, a hydrogen bond between the R275 side-chain and the carbonyl oxygen of D267 is broken, destabilizing the F260-L271 loop structure and the protein. This promotes the formation of dimers/aggregates and suggests that an increased cellular degradation is the molecular mechanism by which R275C causes GCK-MODY.     

Type 1 hyperlipoproteinemia due to a novel deletion of exons 3 and 4 in the GPIHBP1 gene

Objectives

Type 1 hyperlipoproteinemia is an autosomal recessive disorder characterized by severely elevated plasma triglyceride levels, which may lead to abdominal pain and pancreatitis, eruptive xanthomas and failure to thrive. Mutations in the genes encoding lipoprotein lipase (LPL), apolipoprotein CII (APOC2), apolipoprotein AV (APOA5), lipase maturing factor 1 (LMF1) or glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) have been found to cause Type 1 hyperlipoproteinemia.

Methods

Two sibpairs belonging to two different branches of an extended pedigree were referred for molecular elucidation for their increased plasma triglyceride levels, which untreated were >27 mmol/L. The genes LPL, APOC2, APOA5, LMF1 and GPIHBP1 were analyzed by DNA sequencing.

Results

No mutations were found in LPL, APOC2, APOA5 or LMF1. No PCR products were obtained for exons 3 and 4 of GPIHBP1 from DNA of the 4 affected subjects. Subsequent long-range PCR revealed that the four affected were homozygous for a deletion comprising exons 3 and 4 of GPIHBP1. No increase in LPL activity was found in post-heparin plasma from the subjects.

Conclusion

Homozygosity for a deletion of exons 3 and 4 of GPIHBP1 results in Type 1 hyperlipoproteinemia.