Relationship of actin filament assembly to clearance of fibrinogen gold, GPIIb-IIIa complexes on spread platelets

Abstract. The present study has evaluated the influence of high concentrations of cytochalasins B and E on the detergent-resistant actin levels in fully spread platelets by PAGE gel electrophoresis, and the effects of the two inhibitors of new actin filament assembly on translocation of fibrinogen gold (Fgn/Au) labelled GPIIb-IIIa receptors on the surface-activated cells. Concentrations of 10^{- 4}m and 10^-5 m cytochalasin B and E reduced detergent-resistant actin in fully spread platelets to levels present in resting discoid platelets in suspension. Despite reduction of actin filaments to levels in resting cells, cytochalasin B did not prevent translocation of Fgn/Au from platelet margins into channels of the open canalicular system (OCS). Similar concentrations of cytochalasin E completely blocked translocation of receptor-ligand complexes and produced a patching phenomenon not observed in previous studies. Rinsing of the spread cells to remove cytochalasin, followed by incubation of the treated platelets in Hank's buffered salt solution (HBSS) restored levels of detergent-resistant actin to those found in untreated, spread platelets. Resting grids of 10 ⁵ m cytochalasin E-treated platelets on drops of HBSS for 15min restored their ability to clear FGN/Au linked to GPIIb-IIIa from exposed surfaces to the OCS, but 10^-4 m cytochalasin E-treated cells remained anergic after incubation on drops of HBSS. Thus a fully assembled cytoplasmic actin filament cytoskeleton does not appear to be essential for translocating receptor-ligand complexes on the platelet surface to the OCS, nor does its presence guarantee that the ability to clear GPIIb-IIIa receptors will be restored.     

Outcomes of Donation After Circulatory Death Heart Transplantation in Australia

Background

Transplantation of hearts retrieved from donation after circulatory death (DCD) donors is an evolving clinical practice.

The 5-Year Course of Obsessive-Compulsive Symptoms and Obsessive-Compulsive Disorder in First-Episode Schizophrenia and Related Disorders

Objective: To determine the course of obsessive-compulsive symptoms (OCS) and obsessive-compulsive disorder (OCD) in first-episode schizophrenia and related disorders and their relationship with clinical characteristics. Methods: Consecutively, admitted patients with a first-episode of schizophrenia, schizophreniform disorder, or schizoaffective disorder were screened for OCS, and these were measured with the Yale-Brown Obsessive-Compulsive Scale. Positive and Negative Syndrome Scale and Montgomery Åsberg Depression Rating Scale were used to assess severity of other symptoms. The course of 3- and 5-year symptoms, psychotic relapse, substance use, remission, full recovery, suicide, and social functioning were assessed. Results: One hundred and eighty-six consecutively admitted and consenting patients were included. Five years after admission, OCS could be assessed in 172 patients. Ninety-one patients (48.9%) reported no OCS symptoms on any of the assessments. OCS restricted to the first assessments occured in 15.1%, 13.4% had persistent OCS, 7.0% had no OCS at first assessment but developed OCS subsequently, and 15.6% had intermittent OCS. The proportion of patients with comorbid OCD varied between 7.3% and 11.8% during follow-up. OCD was associated with more severe depressive symptoms and poorer premorbid functioning and social functioning at follow-up. Conclusions: The 5-year course of OCS/OCD in patients with first-episode schizophrenia or related disorders is variable. OCS/OCD comorbidity was not associated with a more severe course of psychotic symptoms and relapse. Comorbid OCD was associated with more severe depressive symptoms, social dysfunction and worse premorbid functioning. Specific treatment options for schizophrenia patients with comorbid OCD are needed.     

骨筋膜室综合征诊断研究进展

骨筋膜室综合征是各种原因导致筋膜室内容物增多、容积减小、压力升高,进而引起一系列肌肉神经症状。(Osteofascial Compartment Syndrome,OCS)重在早期诊断、早期切开,但目前临床常用的诊断方法,如根据临床症状“5P”征诊断骨筋膜室综合征有很多局限性,当患者出现“5P”征时往往病情已经进展到晚期,所以限制了临床的应用。OCS属中医学“筋伤”范畴,多属实证。机体受到创伤后必损气血,血不循经,溢于脉外,闭阻经脉不通,影响气机运行,而致肿胀疼痛,出现气滞血瘀,治宜活血消肿、行气止痛。中医药在创伤早期干预会对OCS产生积极影响。下面笔者将目前OCS的诊断方法及中医药研究进行综述。     

Efficacy and safety of mepolizumab in Japanese patients with severe eosinophilic asthma

Background

The MENSA trial assessed the efficacy and safety of mepolizumab in patients with severe eosinophilic asthma. This report describes the efficacy and safety of mepolizumab in Japanese patients from MENSA.

Influence of cell-free Hb on local tissue perfusion and oxygenation in acute anemia after isovolemic hemodilution

BACKGROUND: Oxygen-carrying solutions are intended to eliminate the blood transfusion trigger. Their ability to maintain microvascular perfusion and to deliver oxygen to tissue when they replace the RBCs as oxygen carriers has not been directly measured. STUDY DESIGN AND METHODS: Microvascular response to exchange transfusion with a polymerized bovine cell-free Hb (PBH) solution after acute isovolemic hemodilution with a plasma expander was investigated by using the hamster window model. In vivo functional capillary density (FCD), blood flow, and high-resolution oxygen distribution in microvascular networks were measured by noninvasive methods. RESULTS: Exchange transfusion of PBH solution after a 60-percent isovolemic hemodilution with dextran 70 (MW, 70 kDa) resulted in a Hct of 11 percent and a Hb content of 6.7 g per dL. FCD was 0.37 of baseline. Interstitial pO2 was reduced from 21.0 mm Hg to 0.3 mmHg. Arteriolar and venular blood flows were ratios of 0.75 and 0.76 relative to baseline. In a previous study, tissue pO2 after hemodilution to 5.6 g of Hb per dL with dextran 70 was 23.0 mmHg. Hypervolemic injection of PBH solution increased blood pressure and caused vasoconstriction. CONCLUSION: Using PBH solution to replace RBC oxygen-carrying capacity during low Hb content conditions (<50%) causes abnormally low tissue oxygenation and FCD, while the same level of hemodilution with dextran maintains normal microvascular conditions.