Coordinated inhibition of actin-induced platelet aggregation by plasma gelsolin and vitamin D-binding protein

Actin is an abundant intracellular protein that is released into the blood during tissue injury and its injection into rats causes microthrombi to form in the vasculature. This report and others have shown that actin filaments are able to aggregate platelets in an adenosine diphosphate (ADP)-dependent manner. The effects on this process of two plasma actin-binding proteins, vitamin D-binding protein (DBP) and gelsolin, were examined separately and together. The addition of DBP, a monomer-binding protein, to actin filaments did not affect their ability to induce platelet aggregation. However, severing of actin filaments with gelsolin resulted in an increased degree of platelet aggregation. Preincubation of F-actin with both gelsolin and DBP resulted in a significant inhibition of aggregation. The effects of DBP and gelsolin on actin-induced aggregation paralleled their effects on exchange of actin-bound adenine nucleotides. DBP inhibited 1, N6- ethenoadenosine 5' triphosphate (epsilon-ATP) exchange with G-actin but not with F-actin. Gelsolin increased epsilon-ATP exchange with F-actin, which was largely abrogated by the addition of DBP. These results suggest that gelsolin's severing (and subsequent capping) of actin filaments not only results in an increase in the number of pointed filament ends but also in the dissociation of actin monomers containing ADP. Phalloidin, which stabilizes actin filaments while decreasing both monomer and nucleotide exchange, inhibited actin-induced aggregation, as well, indicating that depolymerization of actin filaments is not required to inhibit aggregation. Platelet activation by either G- or F- actin may thus be regulated by the local concentrations of the plasma actin-binding proteins gelsolin and DBP. Together, these proteins inhibit platelet aggregation in a manner that can be explained by their effects on actin's filament structure and the accessibility of its bound ADP. Depletion of DBP or gelsolin may allow actin released from injured tissues to stimulate purinergic receptors on platelets, and perhaps other cells, via its bound adenine nucleotides.     

Quantitation of erythropoietin-producing cells in kidneys of mice by in situ hybridization: correlation with hematocrit, renal erythropoietin mRNA, and serum erythropoietin concentration

In situ hybridization was used to quantitate the cells that produce erythropoietin (EP) in the renal cortices of mice with varying severities of acute anemia and of mice recovering from severe, acute anemia. The number of EP-producing cells in the renal cortex increased in an exponential manner as hematocrit was decreased. Individual EP- producing cells had very similar densities of silver grains in autoradiograms regardless of whether they were from normal mice or from slightly, moderately or severely anemic animals. With increasingly severe anemia, total renal EP mRNA levels and serum EP concentrations showed increases that correlated with the number of renal EP-producing cells. These results indicate that as mice become more anemic, additional cells are recruited to produce EP rather than the cells already producing EP being stimulated to increase their individual production. In mildly and moderately anemic animals, small clusters of EP-producing cells were found in the inner cortex with large areas of cortex containing no EP-producing cells. In severely anemic mice, EP- producing cells were found throughout the inner cortex with only a very few found scattered in the outer cortex and outer medulla. The data indicate that only a subset of total renal interstitial cells produce EP. During recovery from severe, acute anemia, the numbers of EP- producing cells decreased exponentially as hematocrits rose and correlated with decreases in total renal EP mRNA and serum EP concentrations. These results suggest that following an acute blood loss and during the recovery from a blood loss, the capacity to deliver oxygen, as represented by hematocrit, is the major regulator of EP production.     

Randomized,Double-Blind,Placebo-Controlled Study of Encenicline,an α7 Nicotinic Acetylcholine Receptor Agonist,as a Treatment for Cognitive Impairment in Schizophrenia

Encenicline is a novel, selective α7 nicotinic acetylcholine receptor agonist in development for treating cognitive impairment in schizophrenia and Alzheimer''s disease. A phase 2, double-blind, randomized, placebo-controlled, parallel-design, multinational study was conducted. Patients with schizophrenia on chronic stable atypical antipsychotics were randomized to encenicline 0.27 or 0.9 mg once daily or placebo for 12 weeks. The primary efficacy end point was the Overall Cognition Index (OCI) score from the CogState computerized battery. Secondary end points include MATRICS Consensus Cognitive Battery (MCCB) (in US patients), the Schizophrenia Cognition Rating Scale (SCoRS) total score, SCoRS global rating, and Positive and Negative Syndrome Scale (PANSS) total and subscale and cognition factor scores. Of 319 randomized patients, 317 were included in the safety population, and 307 were included in the intent-to-treat population. Notable trends in improvement were demonstrated across all cognition scales. For the OCI score, the LS mean difference for encenicline 0.27 mg vs placebo was significant (Cohen''s d=0.257; P=0.034). Mean SCoRS total scores decreased showing improvement in function over time, and the difference was significant for encenicline 0.9 mg vs placebo (P=0.011). Furthermore, the difference between encenicline 0.9 mg and placebo was significant for the PANSS Cognition Impairment Domain (P=0.0098, Cohen''s d=0.40) and for the PANSS Negative scale (P=0.028, Cohen''s d=0.33). Treatment-emergent adverse events were reported at similar frequencies across all treatment groups (39.0% with placebo, 23.4% with encenicline 0.27 mg, and 33.3% with encenicline 0.9 mg). Overall, encenicline was generally well tolerated and demonstrated clinically meaningful improvements in cognition and function in patients with schizophrenia.     

Proportion of Gestational Diabetes Mellitus Attributable to Overweight and Obesity Among Non-Hispanic Black,Non-Hispanic White,and Hispanic Women in South Carolina

Objective was to estimate race-specific proportions of gestational diabetes mellitus (GDM) attributable to overweight and obesity in South Carolina. South Carolina birth certificate and hospital discharge data were obtained from 2004 to 2006. Women who did not have type 2 diabetes mellitus before pregnancy were classified with GDM if a diagnosis was reported in at least one data source. Relative risks (RR) and 95 % confidence intervals were calculated using the log-binomial model. The modified Mokdad equation was used to calculate population attributable fractions for overweight body mass index (BMI: 25.0–29.9 kg/m²), obese (30.0–34.9 kg/m²), and extremely obese (≥35 kg/m²) women after adjusting for age, gestational weight gain, education, marital status, parity, tobacco use, pre-pregnancy hypertension, and pregnancy hypertension. Overall, the adjusted RR of GDM was 1.6, 2.3, and 2.9 times higher among the overweight, obese, and extremely obese women compared to normal-weight women in South Carolina. RR of GDM for extremely obese women was higher among White (3.1) and Hispanic (3.4) women than that for Black women (2.6). The fraction of GDM cases attributable to extreme obesity was 14.0 % among White, 18.1 % among Black, and 9.6 % among Hispanic women. The fraction of GDM cases attributable to obesity was about 12 % for all racial groups. Being overweight (BMI: 25.0–29.9) explained 8.8, 7.8, and 14.4 % of GDM cases among White, Black, and Hispanic women, respectively. Results indicate a significantly increased risk of GDM among overweight, obese, and extremely obese women. The strength of the association and the proportion of GDM cases explained by excessive weight categories vary by racial/ethnic group.     

The effects and effectiveness of electromotive drug administration and chemohyperthermia for treating non-muscle invasive bladder cancer

Introduction

Preliminary studies show that device assisted intravesical therapies appear more effective than passive diffusion intravesical therapy for the treatment of non-muscle invasive bladder cancer (NMIBC) in specific settings, and phase III studies are now being conducted. Consequently, we have undertaken a non-systematic review with the objective of describing the scientific basis and mechanisms of action of electromotive drug administration (EMDA) and chemohyperthermia (CHT).

Methods

PubMed, ClinicalTrials.gov and the Cochrane Library were searched to source evidence for this non-systematic review. Randomised controlled trials, systematic reviews and meta-analyses were evaluated. Publications regarding the scientific basis and mechanisms of action of EMDA and CHT were identified, as well as clinical studies to date.

Results

EMDA takes advantage of three phenomena: iontophoresis, electro-osmosis and electroporation. It has been found to reduce recurrence rates in NMIBC patients and has been proposed as an addition or alternative to bacillus Calmette–Guérin (BCG) therapy in the treatment of high risk NMIBC. CHT improves the efficacy of mitomycin C by three mechanisms: tumour cell cytotoxicity, altered tumour blood flow and localised immune responses. Fewer studies have been conducted with CHT than with EMDA but they have demonstrated utility for increasing disease-free survival, especially in patients who have previously failed BCG therapy.

Conclusions

It is anticipated that EMDA and CHT will play important roles in the management of NMIBC in the future. Techniques of delivery should be standardised, and there is a need for more randomised controlled trials to evaluate the benefits of the treatments alongside quality of life and cost-effectiveness.     

Use of the surgical Apgar score to guide postoperative care

Introduction

The surgical Apgar score (SAS) can predict 30-day major complications or death after surgery. Studies have validated the score in different patient populations and suggest it should be used to objectively guide postoperative care. We aimed to see whether using the SAS in a decisive approach in a future randomised controlled trial (RCT) would be likely to demonstrate an effect on postoperative care and clinical outcome.

Methods

A total of 143 adults undergoing general/vascular surgery in 9 National Health Service hospitals were recruited to a pilot single blinded RCT and the data for 139 of these were analysed. Participants were randomised to a control group with standard postoperative care or to an intervention group with care influenced (but not mandated) by the SAS (decisive approach). The notional primary outcome was 30-day major complications or death.

Results

Incidence of major complications was similar in both groups (control: 20/69 [29%], intervention: 23/70 [33%], p=0.622). Immediate admissions to the critical care unit was higher in the intervention group, especially in the SAS 0–4 subgroup (4/6 vs 2/7) although this was not statistically significant (p=0.310). Validity was also confirmed in area under the curve (AUC) analysis (AUC: 0.77).

Conclusions

This pilot study found that a future RCT to investigate the effect of using the SAS in a decisive approach may demonstrate a difference in postoperative care. However, significant changes to the design are needed if differences in clinical outcome are to be achieved reliably. These would include a wider array of postoperative interventions implemented using a quality improvement approach in a stepped wedge cluster design with blinded collection of outcome data.     

The malignant cells in a Lennert's lymphoma are T lymphocytes with a mature helper surface phenotype. A multiparameter flow cytometric analysis

The flow cytometric analysis of DNA content in cells obtained from a case of Lennert's lymphoma demonstrated the presence of a discrete hypotetraploid cell population. Correlated multiparameter analysis of DNA, light scatter, and surface antigens by flow cytometry showed that the hypotetraploid cells were intermediate to large cells expressing T11, T3, and T4 antigens and lacking B1 and T8 antigens. These findings suggest that Lennert's lymphoma represents a malignant neoplasm of T- helper lymphocytes.     

Electrophysiology of esmolol

The electrophysiologic characteristics of esmolol were studied in 14 patients. Ten men and 4 women, mean age 57 years, were electrophysiologically evaluated at baseline, and also at 4 to 8 minutes after the administration of a maintenance infusion of esmolol. Plasma samples for esmolol blood levels were drawn at 10 minutes of the maintenance infusion, at the end of the maintenance infusion and 30 minutes after the maintenance infusion was discontinued. Results of this study showed that esmolol has typical beta-blocker electrophysiologic effects. Its major action was on sinus node function; it prolonged this basic sinus cycle length but had no significant effect on intrinsic automaticity as reflected by the corrected sinus node recovery time and sinoatrial conduction. Direct effects on atrioventricular (AV) nodal function were reflected by effects on AV nodal conduction and refractoriness. There was no direct effect on atrial function and, as expected, no effect on His-Purkinje or ventricular function. The intensity of esmolol's electrophysiologic effects on sinus node function, AV nodal conduction and AH interval is comparable to those of other beta blockers.     

Establishment of a new human pancreatic adenocarcinoma cell line, MDAPanc-3.

A new cell line was established from a liver metastasis of a human pancreatic adenocarcinoma. The cell line, MDAPanc-3, which arose from a moderately differentiated adenocarcinoma, produces carbonic anhydrase II mRNA, but no detectable levels of insulin or alpha amylase mRNA. The stem line chromosome number was determined to be 43, with six marker chromosomes. Growth of MDAPanc-3 is stimulated by cholecystokinin (CCK) fragment 26-33. The cell line will be useful in further studies on the mechanism(s) by which CCK stimulates growth of certain human pancreatic adenocarcinomas and normal human pancreatic exocrine tissue.