Electromyographic biofeedback in the treatment of voluntary posterior instability of the shoulder

Three cases of voluntary posterior instability of the shoulder are presented. They have all responded well to a program of electromyographic monitored biofeedback. This method offers a means of enhancing the results of nonoperative treatment.     

Ester und Stereoisomere

This review discusses concepts of isomers, stereoisomers, chirality, and enantiomers as applied to drugs used in anaesthesia. The inhalational anaesthetics enflurane and isoflurane are examples of stereoisomers. A chiral centre is formed when a carbon or quaternary nitrogen atom is connected to four different atoms. A molecule with one chiral centre is then present in one of two possible configurations termed enantiomers. A racemate is a mixture of both enantiomers in equal proportions. Many of the drugs used in anaesthesia are racemic mixtures (the inhalational anaesthestics, local anaesthetics, ketamine, and others). The shape of the atracurium molecule is comparable to that of a dumb-bell: the two isoquinoline groups representing the two bulky ends connected by an aliphatic chain. In each isoquinoline group there are two chiral centres, one formed by a carbon and the other by a quaternary nitrogen atom. From a geometric point of view, the connections from the carbon atom to a substituted benzene ring and from the quaternary nitrogen to the aliphatic chain may point in the same direction (cis configuration) or in opposite directions (trans configuration). The two isoquinoline groups in atracurium are paired in three geometric configurations: cis-cis, trans-trans, or cis-trans. However, the two chiral centres allow each isoquinoline group to exist in one of four stereoisomeric configurations. In the symmetrical atracurium molecule, the number of possible stereoisomers is limited to ten. Among these, 1 R-cis, 1′ R-cis atracurium was isolated and its pharmacologic properties studied. This isomer, named cis-atracurium, offers clinical advantages over the atracurium mixture, principally due to the lack of histamine-releasing propensity and the higher neuromuscular blocking potency. The ester groups appear in one of two steric configurations true and reverse esters. In the true esters, oxygen is positioned between the nitrogen atom and the carbonyl group, while in the reverse esters it is positioned on the other side of the carbonyl group. True esters, suxamethonium and mivacurium, are hydrolysed by the enzyme plasma cholinesterase (butyrylcholinesterase), albeit at different rates. The more rapid degradation of suxamethonium is responsible for its fast onset and short duration of action in comparison with mivacurium. The reverse esters, atracurium, cisatracurium, and remifentanil, are hydrolysed by nonspecific esterases in plasma (carboxyesterases). Remifentanil is hydrolysed rapidly; the degradation leads to its inactivation and short duration of action. Cis-atracurium is preferentially degraded and inactivated by a process known as Hofmann elimination. In a second step, one of the degradation products, the monoester acrylate, is hydrolysed by a nonspecific esterase.     

Letales Karotissinussyndrom

Report of a case with lethal bleeding into the cervical soft tissue after inadvertent puncture of the carotid artery. After sudden and unexpected cardiac arrest resuscitation was started immediately but intubation failed. Stenosis of the trachea due to hematoma following the puncture was discussed as cause of death as well as thrombembolism and an early septic process. Autopsy revealed an extensive retropharyngeal hematoma but no stenosis of the upper airways. Histological investigations showed extensive bleeding surrounding the sinus caroticum with subcapsular hemorrhages. The sudden onset of the cardiac arrest could have been initiated by a hemorrhage-induced irritation of the sinus caroticum. In the cases reported a lethal irritation of the carotid sinus following external violence has been surmised and there exists only one case report with comparable histological findings from inside and around the glomus caroticum.     

Cognitive-behavioral treatment of late-life generalized anxiety disorder

This study addressed the efficacy of cognitive-behavioral therapy (CBT), relative to minimal contact control (MCC), in a sample of 85 older adults (age 60 years and over) with generalized anxiety disorder (GAD). All participants completed measures of primary outcome (worry and anxiety), coexistent symptoms (depressive symptoms and specific fears), and quality of life. Results of both completer and intent-to-treat analyses revealed significant improvement in worry, anxiety, depression, and quality of life following CBT relative to MCC. Forty-five percent of patients in CBT were classified as responders, relative to 8% in MCC. Most gains for patients in CBT were maintained or enhanced over 1-year follow-up. However, posttreatment scores for patients in CBT failed to indicate return to normative functioning.     

Contrasting roles of DAP10 and KARAP/DAP12 signaling adaptors in activation of the RBL-2H3 leukemic mast cell line

A common feature of hematopoietic activating immunoreceptors resides in their association at the cell surface with transmembrane signaling adaptors. Several adaptors, such as the CD3 molecules, FcRgamma and KARAP/DAP12, harbor intracytoplasmic immunoreceptor tyrosine-based activation motifs (ITAM) that activate Syk-family protein tyrosine kinases. In contrast, another transmembrane adaptor, DAP10, bears a YxxM motif that delivers signals by activation of lipid kinase pathways. We show here that the human signal-regulatory protein SIRPbeta1 can associate with both DAP10 and KARAP/DAP12 in a model of RBL-2H3 cell transfectants. In association with KARAP/DAP12, SIRPbeta1 complexes are capable of inducing serotonin release and tumor necrosis factor (TNF) secretion. By contrast,in the absence of KARAP/DAP12, engagement of SIRPbeta1:DAP10 complexes does not lead to detectable serotonin release or TNF secretion by RBL-2H3 transfectants. However, triggering of SIRPbeta1:DAP10 complexes co-stimulates RBL-2H3 effector function induced by sub-optimal stimulation of the endogenous FcepsilonRI complex. Therefore, we report here a cellular model in which the association of a cell surface receptor with various signaling adaptors dictates the co-stimulatory or the direct stimulatory properties of the complex.     

A comparison of robotic-assisted splenectomy and laparoscopic splenectomy for children with hematologic disorders

IntroductionLaparoscopic splenectomy (LS) is the standard of care for hematologic disorders requiring splenectomy. Less is known about the outcomes following robotic-assisted splenectomy (RS) for this indication. Our aim was to describe outcomes of RS to LS in pediatric patients with hematologic disorders in our institution.MethodsA single institution retrospective review was performed of pediatric patients undergoing LS vs. RS from 2014 to 2019. Patient demographics, diagnosis, spleen size, hospital length of stay (LOS), operative time, post-operative opioid use, and hospital charges were evaluated. Standard univariate analyses were performed.ResultsTwenty-four patients were included in the study (14 LS, 10 RS). The mean spleen size at the time of surgery was larger in the RS group compared to LS (14.5 cm vs. 12.2 cm, p = 0.03). Operative time between the two cohorts was comparable (RS 140.5 vs LS 154.9 min). Median LOS for RS was shorter than LS (2.1 vs. 3.2 days, p = 0.02). Cumulative postoperative opioid analgesic requirements were not significantly different between the groups (17.4 mg vs. 30.5 mg). The median hospital charges, including the surgical procedure and hospital stay were higher in the RS group ($44,724 RS vs $30,255 LS, p = 0.01).ConclusionRobotic splenectomy is a safe and feasible option for pediatric patients with hematologic disorders, and was associated with decreased LOS but higher charges compared to laparoscopic splenectomy. Further studies are required to delineate the optimal use and potential benefits of robot-assisted surgical techniques in children.Level of EvidenceII.     

Blutsperre und Muskelrelaxation

Ohne Zusammenfassung     

Mechanical and Thermal Influences on Microstructural and Mechanical Properties during Process-Integrated Thermomechanically Controlled Forging of Tempering Steel AISI 4140

Thermomechanical treatment (TMT) describes the effect of thermal and mechanical conditions on the microstructure of materials during processing and offers possible integration in the forging process. TMT materials exhibit a fine-grained microstructure, leading to excellent mechanical properties. In this study, a two-step TMT upsetting process with intermediate cooling is used to demonstrate possibilities for a process-integrated treatment and corresponding properties. A water–air-based cooling system was designed to adjust different phase configurations by varying the target temperature and cooling rate. Four different thermal processing routes and four combinations of applied plastic strains are investigated in standardized mechanical tests and metallographic analyses. The applied TMT results in a finely structured bainitic microstructure of the investigated tempering steel AISI 4140 (42CrMo4) with different characteristics depending on the forming conditions. It can be shown that the demands of the standard (DIN EN ISO 683) in a quenched and tempered state can be fulfilled by means of appropriate forming conditions. The yield strength can be enhanced up to 1174 MPa while elongation at break is about 12.6% and absorbed impact energy reaches 58.5 J without additional heat treatment when the material is formed after rapid cooling.