Platelet alpha-granule and plasma membrane share two new components: CD9 and PECAM-1

CD9 (p24) and PECAM1 (CD31) antigens are well-defined components of the platelet plasma membrane. Both are integral glycoproteins (GPs) implicated in the adhesive and aggregative properties of human platelets. In the present report, we have investigated their subcellular localization using immunoelectron microscopy. The monospecificity of the two polyclonal antibodies used was confirmed by immunoblotting. On normal resting platelets, immunolabeling for CD9 and PECAM1 was found lining the plasma membrane and the luminal face of the open canalicular system. Some labeling was also consistently found on the alpha-granule limiting membrane. This was confirmed by double labeling experiments in which fibrinogen and von Willebrand factor (vWF) were used as alpha-granule markers. CD9 and PECAM-1 were found lining the membrane of the same granules that contained fibrinogen and vWF in their matrix. CD9 and PECAM-1 thus appear to have an intracellular distribution identical to GPIIb-IIIa, a major aggregation platelet receptor. To rule out a cross-reactivity of the two polyclonal antibodies with GPIIb/IIIa, we studied PECAM1 and CD9 expression on the platelets from a patient with type I Glanzmann's thrombasthenia whose platelets are devoid of GPIIb/IIIa. The same pattern of labeling was observed for both antigens as for normal platelets. Normal platelets were further observed after stimulation by agonists that either fail to induce (ADP) or induce granule secretion (thrombin). After treatment with ADP, platelets changed shape and centralized their granules; the plasma membrane immunolabeling remained unchanged; and gold particles were still found decorating the periphery of the centralized alpha- granules. After thrombin treatment, alpha-granules fused with the platelet membrane and secretion occurred. A significant increase of labeling was then observed on the platelet surface. From these results we conclude that the alpha-granule membrane contains two additional receptors in common with the plasma membrane. This suggests that alpha- granule membrane receptors may originate from a dual mechanism: direct targeting from the Golgi complex in megakaryocytes (for alpha-granule- specific receptors such as P-selectin) or by endocytosis from the plasma membrane (for proteins distributed in the two compartments).     

Analysis of exercise-induced R wave amplitude changes in detection of coronary artery disease in asymptomatic men with left bundle branch block

The exercise electrocardiograms of 44 asymptomatic men with acquired left bundle branch block were analyzed for changes in R wave amplitude. Results were correlated with findings on selective coronary angiography. There were two subgroups: 7 men with significant angiographic coronary artery disease (Group I) and 37 with normal coronary angiograms (Group II). Exercise induced an increase in R wave amplitude in all seven men with coronary artery disease but in only 10 of the 37 men without significant coronary artery disease. This criterion thus had a sensitivity of 100 percent but a poor specificity of 73 percent, a predictive value of 41 percent and an accuracy rate of 77 percent for the diagnosis of coronary artery disease. The greater the increase in R wave amplitude the greater was the likelihood of some degree of left ventricular dysfunction as measured by wall motion abnormalities and elevated left ventricular end-diastolic pressure. The increase in R wave amplitude with exercise appears to be a sensitive test in identifying coronary artery disease in asymptomatic men with acquired left bundle branch block.     

Discordant intracellular and plasma D-2-hydroxyglutarate levels in a patient with IDH2 mutated angioimmunoblastic T-cell lymphoma

Objectives: Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive peripheral T-cell lymphoma with mutations in genes encoding isocitrate dehydrogenase1 and 2 (IDH1 and IDH2). Mutant IDH generates the oncometabolite D-2-hydroxyglutarate (D-2HG). We report the first case of discordant intracellular and plasma D-2HG levels in a patient with IDH2 R172S mutated AITL. Methods: An 87-year-old woman was diagnosed with AITL in the groin lymph node by morphologic and immunophenotypic analyses, and molecular studies by DNA sequencing. D-2HG was measured in both tumoral tissue and in pre-treatment plasma by liquid chromatography-tandem mass spectrometry. Results: While D-2HG was markedly elevated in the tissue sample, its level in plasma was normal. We discuss this discordant D-2HG result within the context of previously reported discordant 2HG results in other IDH mutated tumors, and its implication for using circulating D-2HG as a biomarker of IDH mutation. In addition, this case also harbored mutations in RHOA, TET2, and TP53. The molecular pathogenesis is briefly discussed. Conclusion: While our case suggests that circulating D-2HG is not a reliable marker of IDH mutation in AITL, more cases need to be studied to arrive at a definite conclusion.     

Epidemiological features and specificities of HCV infection: a hospital-based cohort study in a university medical center of Calabria region

The epidemiological status of HCV in Europe, and in particular in Mediterranean countries, is continuously evolving. The genotype distribution is related to improvement of healthcare conditions, expansion of intravenous drug use and immigration. We review and characterize the epidemiology of the distribution of HCV genotypes within Calabria, an area of Southern Italy. We focus on the pattern of distinct HCV genotype changes over the last 16 years; particularly subtype 1b and genotype 4. We collected data by evaluating a hospital-based cohort of chronic hepatitis C patients; in addition, we report an update including new patients enrolled during last eight months.     

Longitudinal Impact of a Randomized Clinical Trial to Improve Family Function,Reduce Maternal Stress and Improve Child Outcomes in Families of Children with ADHD

Objective Evaluate the efficacy of a 12 month nursing case-management intervention over a period of 18 months, 6 months after the end of intervention, for families of children attention deficit hyperactivity disorder (ADHD). Methods Mother and child dyads were enrolled to participate in a randomized controlled clinical trial. Children were 4–18 years old. Data were collected at baseline, 6, 12, and 18 months or 6 months after the termination of direct intervention. Longitudinal analyses, using generalized estimating equations, were conducted to assess change in study outcomes relating to family function, maternal stress, and child behavior over the 18 month period. Results Compared to control families, some family function outcomes were moderately improved in the intervention group. In particular, intervention families demonstrated substantial improvement in implementing family behavior controls (p value?=?0.038) and improvement in family satisfaction (not statistically significant p?=?0.062). Although there was improvement in the overall family function measure there was not a statistically significant difference between groups. Maternal stress and child behavior outcomes were not significantly different between control and intervention groups by the end of the intervention. Conclusions for Practice Addressing ADHD is complex and requires the assessment of comorbidities that might exacerbate negative behavior. Our findings support the latest American Academy of Pediatrics guidelines to use behavioral therapy as the first line of treatment in young children. Nursing case-management interventions that provide direct family education and improve family function, especially with respect to providing structure and behavior control, may complement and facilitate behavioral therapy for treatment of ADHD and improving child behavior.     

Intracortical haematogenous osteomyelitis

We present an unusual case of haematogenous osteomyelitis in the diaphysis of the tibia of an adult leading to a subacute presentation with an extracortical abscess. Fluid from the abscess grew methicillin resistant Staphylococcus aureus (MRSA) on culture; MRSA with the same antibiogram had been grown from the patient’s blood seven years earlier following a bowel resection. Drainage of the abscess and curettage of the bone lesion together with appropriate antibiotic therapy led to resolution of the osteomyelitis.     

Combining Self-Affirmation and Implementation Intentions: Evidence of Detrimental Effects on Behavioral Outcomes

Background

There is limited evidence that self-affirmation manipulations can promote health behavior change.

Purpose

The purpose of this study was to explore whether the efficacy of a self-affirmation manipulation at promoting exercise could be enhanced by an implementation intention intervention.

Methods

Participants (Study 1?N?=?120, Study 2?N?=?116) were allocated to one of four conditions resulting from the two (self-affirmation manipulation: no affirmation, affirmation) by two (implementation intention manipulation: no implementation intention, implementation intention) experimental design. Exercise behavior was assessed 1 week post-intervention.

Results

Contrary to prediction, those participants receiving both manipulations were significantly less likely to increase the amount they exercised compared to those receiving only the self-affirmation manipulation.

Conclusion

Incorporating an implementation intention manipulation alongside a self-affirmation manipulation had a detrimental effect on exercise behavior; participants receiving both manipulations exercised significantly less in the week following the intervention.     

The Unique Binding Mode of Laulimalide to Two Tubulin Protofilaments

Laulimalide, a cancer chemotherapeutic in preclinical development, has a unique binding site located on two adjacent β‐tubulin units between tubulin protofilaments of a microtubule. Our extended protein model more accurately mimics the microtubule environment, and together with a 135 ns molecular dynamics simulation, identifies a new binding mode for laulimalide, which differs from the modes presented in work using smaller protein models. The new laulimalide–residue interactions that are computationally revealed explain the contacts observed via independent mass shift perturbation experiments. The inclusion of explicit solvent shows that many laulimalide–tubulin interactions are water mediated. The new contacts between the drug and the microtubule structure not only improve our understanding of laulimalide binding but also will be essential for efficient derivatization and optimization of this prospective cancer chemotherapy agent. Observed changes in secondary protein structure implicate the S7–H9 loop (M–loop) and H1′–S2 loop in the mechanism by which laulimalide stabilizes microtubules to exert its cytotoxic effects.