Glycoprotein Ib polymorphisms influence platelet plug formation under high shear rates

Platelet polymorphisms (Kozak, VNTR and HPA-2) within glycoprotein (GP)Ib alpha may be associated with an increased risk of arterial thrombosis. However, the functional role of these polymorphisms has not been clarified. Their influence on platelet plug formation under high shear rates was, therefore, examined in 233 healthy individuals. Collagen-adrenaline-induced closure time was shorter in carriers of the C/D versus C/C VNTR allele and in homozygotes with the (-5)T/T versus (-5)C/T Kozak genotype as determined by novel polymerase chain reaction methods. The HPA-2 genotype had no effects, and the density of GPIb alpha molecules was not influenced by GPIb alpha genotypes.     

Effectiveness of day hospital treatment for anorexia nervosa and bulimia nervosa

The aim of this observational study was to examine the short‐term effectiveness of a structured, largely manualised day hospital treatment, as well as the stability of short‐term effects in patients with anorexia nervosa (AN) and bulimia nervosa (BN). Eighty‐three patients, 47 with AN and 36 with BN, were assessed at pre‐treatment, at the end of the day hospital treatment and at follow‐up approximately one year after post‐treatment. Outcome measures were body mass index (BMI), disturbed eating attitudes and behaviours assessed by the Eating Disorder Inventory (EDI), frequency of bingeing and purging, and general psychopathology assessed by the Symptom Checklist‐90 (SCL‐90). At the end of the day hospital treatment, significant improvements could be found on all outcome variables (frequency of binge eating/vomiting/laxative abuse, BMI and core EDI‐subscales ‘drive for thinness’/‘bulimia’/‘body dissatisfaction’). Effect sizes were generally large (.74 > d < 2.44). The effects were maintained or improved until follow‐up (18 months). At follow‐up, 40.2% of AN patients and 40.4% of BN patients could be classified as remitted. General psychopathological impairment was also significantly reduced at post‐treatment and maintained until follow‐up. The results demonstrate both the short‐term effectiveness and long‐term stability of day hospital treatment in a large sample of patients with anorexia and BN. Copyright © 2008 John Wiley & Sons, Ltd and Eating Disorders Association.     

Use of body weight and insulin resistance to select obese patients for echocardiographic assessment of subclinical left ventricular dysfunction

Obesity is associated with heart failure. Recognition of subclinical left ventricular (LV) dysfunction may permit the initiation of therapy to prevent the development of heart failure. In this study of anthropometric, biochemical, and echocardiographic measurements in 295 healthy overweight subjects, we sought to investigate the effect of insulin resistance and severity of obesity on LV function and to establish a strategy for detection of LV dysfunction using metabolic and echocardiographic measurements. Correlates of subclinical dysfunction (defined from myocardial deformation in a matched group of 98 slim controls) were sought, and receiver operator characteristic curves for clinical and laboratory parameters were performed to identify optimal cutoffs to permit an effective diagnostic strategy. Subclinical impairment of LV function (average strain<18%) was present in 124 subjects (42%), and 52% of severely obese patients (body mass index [BMI]>35 kg/m2). Independent correlates of strain were BMI (beta=-0.25, p<0.0001), fasting insulin (beta=-0.22, p<0.001), and age (beta=-0.18, p<0.003). In patients with a BMI<35 kg/m2, subclinical impairment was uncommon in the absence of hyperinsulinemia. Using a BMI<35 kg/m2 and an insulin level<13 mIU/L to select patients for further testing allowed echocardiography to be avoided in 35% of subjects in whom the prevalence of LV dysfunction was low. In conclusion, obesity and insulin resistance are important contributors to LV dysfunction, a deleterious effect of hyperinsulinemia on LV performance is particularly seen in overweight and moderately obese subjects, and the combination of BMI, fasting insulin, and echocardiography appears optimal for efficient identification of subclinical LV dysfunction in overweight and obese subjects.     

Short- and long-term COX-2 inhibition reverses endothelial dysfunction in patients with hypertension

Hypertension is associated with endothelial dysfunction that is attributable to oxidative stress and a proinflammatory state. Under these conditions, enhanced expression of cyclooxygenase-2 might lead to increased production of vasoconstrictor prostanoids and reactive oxygen species that reduce the bioavailability of endothelium-derived nitric oxide. To investigate the contribution of cyclooxygenase-2 activity to endothelial dysfunction in human hypertension, we evaluated brachial artery vasodilator function by ultrasound in 29 hypertensive patients before and after treatment with the selective cyclooxygenase-2 inhibitor celecoxib or placebo in a randomized, double-blind study. Brachial artery flow-mediated dilation improved from a baseline of 7.9+/-4.5% to 9.9+/-5.1% (P=0.005) 3 hours after the first dose and to 10.1+/-6.1% (P=0.006) after 1 week of treatment with celecoxib. In contrast, placebo treatment had no significant effect on flow-mediated dilation (8.1+/-4.4%, 8.3+/-3.5%, and 8.0+/-3.2%, respectively). Neither treatment altered nitroglycerin-mediated dilation, extent of reactive hyperemia, or baseline arterial diameter. Celecoxib treatment had no significant effect on the urinary concentrations of F2 isoprostane or thromboxane metabolites. However, urinary concentrations of the prostacyclin metabolite 2,3-dinor-6-ketoprostglandin F1alpha were significantly lower after 1 week of celecoxib treatment. Thus, cyclooxygenase-2 products contribute to endothelial dysfunction in hypertension, and treatment with a cyclooxygenase-2 inhibitor could have a beneficial effect in this setting. However, cyclooxygenase-2 inhibition also has an adverse effect on prostacyclin production that could promote thrombosis, and the net clinical consequences of improved endothelial function versus loss of prostacyclin merits further investigation.     

Rapid suppression of hematopoiesis by standard or pegylated interferon-alpha

BACKGROUND & AIMS: Treatment of chronic hepatitis C with interferon (IFN)-alpha often has hematotoxic effects. We evaluated the effects of acute vs. chronic and standard vs. pegylated IFN-alpha on hematopoiesis. METHODS: We studied hematopoiesis in 46 patients with chronic hepatitis C receiving single high-dose IN-Falpha2b followed by daily dose standard or weekly pegylated IFN before combination antiviral therapy. RESULTS: Single high-dose therapy resulted in a significant drop in hemoglobin (HB), leukocytes, and platelet count. Although platelets, stimulated by a significant increase in thrombopoietin (TPO), and leukocytes recovered quickly, HB remained below baseline for 7 days. Daily standard or weekly pegylated IFN-alpha leads to a more pronounced drop in all 3 lineages with concomitant increases in TPO and erythropoietin (EPO). No difference was observed between standard and pegylated IFN, except for HB, which fell more during pegylated IFN therapy. Consecutive combination antiviral therapy aggravated the anemia but not the drop in leukocytes or thrombocytes. CONCLUSIONS: The drop in all 3 hematopoietic lineages through IFN-alpha treatment, high-dose standard, standard daily dose, or pegylated, is caused by a combination of bone marrow inhibition and probably some other rapid acting mechanisms. Hematopoietic growth factors are increased as a consequence but cannot overcome the bone marrow suppression.     

Influence of COX-2 Inhibition by Rofecoxib on Serum and Tumor Progastrin and Gastrin Levels and Expression of PPARγ and Apoptosis-Related Proteins in Gastric Cancer Patients

Cyclooxygenase-2 (COX-2) expression and certain growth hormones, such as gastrin, have been related to gastric carcinogenesis, but little is known about the factors that enhance this COX-2 expression and whether specific blockade of this enzyme has any influence on tumor growth and progression. Our objective was to determine the influence of a specific COX-2 inhibitor, rofecoxib (Vioxx), on serum and tumor levels of gastrin and its precursor, progastrin, as well as on tumor gene expression of COX-2, peroxisome proliferator-activated receptor gamma (PPAR), and apoptosis-related proteins (Bax and Bcl-2, caspase-3, and survivin). Twenty-four gastric cancer (GC) patients entered this study and were examined twice, once before and then following a 14-day treatment with Vioxx at a dose of 25 mg twice daily. For comparison, 48 age- and sex-matched healthy controls and 24 similarly matched Helicobacter pylori (Hp)-positive subjects were enrolled and treated with Vioxx as GC patients. Serum levels of anti-Hp and anti-CagA antibodies as well as IL-8 and TNF- were measured by enzyme-linked immunosorbent assay (ELISA), while serum and tumor contents of progastrin and amidated gastrin were determined by specific RIA. Tumor gene and protein expressions of COX-2, PPAR, Bax and Bcl-2, caspase-3, and survivin were determined by RT-PCR and western blot. The overall Hp and CagA seropositivity in 24 GC patients was significantly higher (82% and 47%) than in 48 controls (61% and 22%) but not in 24 Hp-infected subjects (100% and 38%). Serum IL-8 and TNF- values were significantly higher in GC patients than in controls without GC or Hp-infected controls. Median serum progastrin and gastrin levels were found to be significantly higher in GC than in controls without GC and in Hp-positive subjects. Treatment of GC patients with Vioxx resulted in a significant decrease in plasma and tumor contents of both progastrin and gastrin, and this was accompanied by the increment in tumor expression of COX-2, PPAR, Bax, and caspase-3 with a concomitant reduction in Bcl-2 and survivin expression. We conclude that: (1) GC patients show significantly higher Hp and CagA seropositivity than age- and sex-matched controls, but not Hp-positive subjects, indicating that infection with cytotoxic Hp is linked to GC. (2) Serum progastrin and gastrin levels are signficantly higher in GC patients than in matched controls, confirming that both gastrins may be implicated in gastric carcinogenesis. (3) GC patients exhibit significantly higher levels of IL-8 and TNF- than non-GC controls and Hp-positive subjects, probably reflecting more widespread gastritis in GC. (4) COX-2, PPAR, Bcl-2, and survivin were overexpressed in gastric tumor, but the inhibition of COX-2 activity by Vioxx resulted in a significant reduction in serum and tumor levels of progastrin and gastrin and serum IL-8 and TNF- levels, suggesting that gastrin and proinflammatory cytokines could mediate the up-regulation of COX-2 in gastric cancerogenesis. (5) Vioxx also enhanced expression of COX-2, PPAR, Bax, and caspase-3, while inhibiting the expression of Bcl-2 and survivin, suggesting that COX-2 blockade might be useful in chemoprevention against cancer possibly due to enhancement of the PPAR- and proapoptotic proteins-dependent apoptosis and the reduction in progastrin/gastrin-induced promotion of tumor growth.     

Priming of normal human neutrophils by recombinant human growth hormone

Growth hormone (GH) plays an important role in the development, maintenance and function of the immune system. Previous data has demonstrated that GH is also a newly defined macrophage-activating factor. Activation of polymorphonuclear neutrophils (PMN) by GH has not yet been examined. This paper presents studies demonstrating the effects of GH on the migratory behaviour and respiratory burst of PMN. In a modified Boyden chamber chemotaxis assay, GH did not stimulate PMN locomotion when added directly to the cells but potently inhibited formylpeptide-stimulated chemotaxis with effective concentrations in the picomolar range. The migration inhibition observed is known from studies on PMN priming-factors to be due to enhanced adhesiveness of PMN to artificial surfaces such as nitrocellulose, suggesting that GH stimulates PMN adhesiveness. Priming of PMN by GH was confirmed by direct demonstration of a stimulatory effect on reduction of nitroblue tetrazolium. These findings suggest that GH may be involved in the regulation of PMN functions.     

An insulin-like peptide regulates egg maturation and metabolism in the mosquito Aedes aegypti

Ingestion of vertebrate blood is essential for egg maturation and transmission of disease-causing parasites by female mosquitoes. Prior studies with the yellow fever mosquito, Aedes aegypti, indicated blood feeding stimulates egg production by triggering the release of hormones from medial neurosecretory cells in the mosquito brain. The ability of bovine insulin to stimulate a similar response further suggested this trigger is an endogenous insulin-like peptide (ILP). A. aegypti encodes eight predicted ILPs. Here, we report that synthetic ILP3 dose-dependently stimulated yolk uptake by oocytes and ecdysteroid production by the ovaries at lower concentrations than bovine insulin. ILP3 also exhibited metabolic activity by elevating carbohydrate and lipid storage. Binding studies using ovary membranes indicated that ILP3 had an IC(50) value of 5.9 nM that was poorly competed by bovine insulin. Autoradiography and immunoblotting studies suggested that ILP3 binds the mosquito insulin receptor (MIR), whereas loss-of-function experiments showed that ILP3 activity requires MIR expression. Overall, our results identify ILP3 as a critical regulator of egg production by A. aegypti.