Detection of platelet associated IgG in immune thrombocytopenia: A new assay employing protein a and peroxidase anti-peroxidase (PROA-PAP)

Immune thrombocytopenia is frequently encountered in medical practice and is generally accepted as being caused by an IgG antibody. The capability of detecting platelet-bound IgG as a diagnostic and therapeutic modality is critical for appropriate care and management of patients with idiopathic thrombocytopenic purpura (ITP), as well as other immune thrombocytopenias We have modified our previous assay (Br J Haematol 37:265, 1977) by employing protein A and PAP as a labeled antibody. Surface bound platelet IgG was quantitated by phase contrast microscopy after incubation with PAP, graded per 100 platelets and expressed as a reactive index (RI). Controls (n=13) had RIs ranging from 0.49 to 0.72 (mean 0.63 ± 0.02 SE). The nonimmune thrombocytopenic group (n=7) had an RI ranging from 0.58 to 0.72 (mean 0.64 ± 0.01 SE). In contrast, the immune thrombocytopenic group (n=28) had RIs ranging from 1.04 to 1.75 (mean 1.43 ± 0.03 SE). Platelet-associated IgG was evaluated further by absorbing representative sera samples from each group against washed granulocytes, red cells and platelets Only when sera from the immune thrombocytopenic group were absorbed against platelets did the reactive indices of pre- and postabsorption samples change significantly. These findings suggest that our assay is clinically applicable in detecting platelet-associated IgG in immune thrombocytopenia and has the advantage of being rapid, reproducible and easy to perform in a clinical laboratory.     

Trophic activity of Rabies G protein-pseudotyped equine infectious anemia viral vector mediated IGF-I motor neuron gene transfer in vitro

The present study examines gene delivery to cultured motor neurons (MNs) with the Rabies G protein (RabG)-pseudotyped lentiviral equine infectious anemia virus (RabG.EIAV) vector. RabG.EIAV-mediated beta-galactosidase (RabG.EIAV-LacZ) gene expression in cultured MNs plateaus 120 h after infection. The rate and percent of gene expression observed are titer-dependent (P < 0.001). The rat IGF-I cDNA sequence was then cloned into a RabG.EIAV vector (RabG.EIAV-IGF-I) and was shown to induce IGF-I expression in HEK 293 cells. MNs infected with RabG.EIAV-IGF-I demonstrate enhanced survival compared to MNs infected with RabG.EIAV-LacZ virus (P < 0.01). In addition, IGF-I expression in cultured MNs induced profound MN axonal elongation compared to control virus (P < 0.01). The enhanced motor neuron tropism of RabG.EIAV previously demonstrated in vivo, together with the trophic effects of RabG.EIAV-IGF-I MN gene expression may lend this vector to therapeutic application in motor neuron disease.     

Future strategies in the treatment of acute renal failure: growth factors, stem cells, and other novel therapies

PURPOSE OF REVIEW: Acute renal failure remains a significant cause of morbidity and mortality in adults and children. Despite advances in understanding the pathophysiology of acute renal failure, little progress has been made in its treatment. This review assesses the recent data on current and promising new therapies for acute renal failure. RECENT FINDINGS: The first section of the review describes the recent therapies that have been used in humans, all of whom have been adults. The second section evaluates the use of agents given in experimental animal models during or after the onset of acute renal failure. The third section describes the many animal studies using therapies before the onset of experimental renal failure. The final section discusses how the emerging field of stem cell research might be used to treat acute renal failure. SUMMARY: Among the recent studies in humans, the most intriguing have been the use of atrial natriuretic peptide in patients with nonoliguric renal failure and isotonic sodium bicarbonate infusions to prevent radiocontrast medium-induced renal failure. Among the agents used in animal studies, those with the greatest potential were hepatocyte growth factor and ethyl pyruvate, because they seem to protect against or accelerate recovery from acute renal failure after the renal insult. Finally, stem cell therapy may someday offer the best option for recovery from acute renal failure.     

Vaso-occlusion in children with sickle cell disease: clinical characteristics and biologic correlates

Vaso-occlusive pain is a frequent manifestation of sickle cell disease, but most clinical studies have documented only those pain episodes for which patients seek acute care or require hospitalization. Based on limited previous studies, the authors suggest that pain episodes managed at home are more frequent then those resulting in acute care management but likely share a common pathophysiology. The authors determined the characteristics of vaso-occlusive pain managed at home in 30 subjects (ages 6-19 years) using a self-report diary daily for 6 months. A total of 175 pain episodes were reported in 4,885 days, with 51% lasting 1 day or less. Severe pain, rated as 7 to 10 on a 10-point scale, was reported on 12% of pain days, but most pain was of mild to moderate intensity. A combination of baseline hematologic parameters and biomarkers assessing erythrocyte/endothelial cell adhesion, including hematocrit, fetal hemoglobin, and adhesion ratio, were statistically significant predictors of pain frequency in statistical analyses. Given the overlap in clinical features and predictive hematologic parameters of home-managed and acute care-managed pain, both likely represent a continuum of frequency and severity rather than distinct clinical entities. The higher frequency of these home-managed episodes suggests their potential utility as additional outcome measures in studies of vaso-occlusive pain.     

Activated protein C preserves functional islet mass after intraportal transplantation: a novel link between endothelial cell activation, thrombosis, inflammation, and islet cell death

Clinical studies indicate that significant loss of functional islet mass occurs in the peritransplant period. Islets are injured as a result of detrimental effects of brain death, pancreas preservation, islet isolation, hypoxia, hyperglycemia, and immune-mediated events. In addition, recent studies demonstrated that islets are injured as a result of their exposure to blood and of activation of intrahepatic endothelial and Kupffer cells, resulting in inflammation and thrombosis. Activated protein C (APC) is an anticoagulant enzyme that also exerts anti-inflammatory and antiapoptotic activities by acting directly on cells. Here, we report that exogenous administration of recombinant murine APC (mAPC) significantly reduced loss of functional islet mass after intraportal transplantation in diabetic mice. Animals given mAPC exhibited better glucose control, higher glucose disposal rates, and higher arginine-stimulated acute insulin release. These effects were associated with reduced plasma proinsulin, intrahepatic fibrin deposition, and islet apoptosis early after the transplant. In vitro and in vivo data demonstrated that mAPC treatment was associated with a significant reduction of proinflammatory cytokine release after exposure of hepatic endothelial cells to islets. mAPC treatment also prevented endothelial cell activation and dysfunction elicited by intrahepatic embolization of isolated islets inherent to pancreatic islet transplantation (PIT). This study demonstrates multiple remarkable beneficial effects of mAPC for PIT and suggests that APC therapy may enhance the therapeutic efficacy of PIT in diabetic patients.     

What can intervention studies tell us about the relationship between fruit and vegetable consumption and weight management?

Given the recent surge in obesity, effective dietary strategies for weight management are required. Because fruits and vegetables are high in water and fiber, incorporating them in the diet can reduce energy density, promote satiety, and decrease energy intake. Although few interventions have specifically addressed fruit and vegetable consumption, evidence suggests that coupling advice to increase intake of these foods with advice to decrease energy intake is a particularly effective strategy for weight management. This approach may facilitate weight loss because it emphasizes positive messages rather than negative, restrictive messages.     

Pesticide Sales in Low-Income, Minority Neighborhoods

The US EPA has phased-out residential use of two organophosphate pesticides commonly used to control cockroaches-retail sales of chlorpyrifos were scheduled to end on 12/31/01, and diazinon on 12/31/02. In light of recent findings highlighting the associations between pests, pesticides and health, we surveyed stores in low-income, minority neighborhoods in New York City to determine whether the phase-outs have been effective and to assess the availability of alternatives to spray pesticides. In summer 2002, when sales of chlorpyrifos were illegal and diazinon still legal, we surveyed 106 stores selling pesticides. Four percent sold products containing chlorpyrifos and 40 percent sold products containing diazinon. One year later, when sales of both pesticides were to have ended, we surveyed 109 stores selling pesticides in the same neighborhoods and found chlorpyrifos in only one store and diazinon in 18 percent of stores, including 80 percent of supermarkets surveyed. At least one form of lower toxicity pesticides, including gels, bait stations and boric acid was available in 69 percent of stores in 2002. However sprays were most widely available, found in 94 percent of stores in 2002 and less expensive than lower toxicity baits and gels. In a separate survey of storekeeper recommendations conducted in 2002, storekeepers recommended lower toxicity pesticides as the best way to control cockroaches 79% of the time. The EPA's phase-outs have nearly eliminated sales of chlorpyrifos, but the diazinon phase-out appears to be less effective.     

Evaluation and comparison of commercially available Aloe vera L. products using size exclusion chromatography with refractive index and multi-angle laser light scattering detection

Raw materials supplied as Aloe vera L. (sometimes referred to as Aloe barbadensis) samples often contain different composition of low and high molecular weight components when analyzed by size exclusion chromatography. One major reason for variable compositions of commercial A. vera L. materials is that they are produced by different manufacturing techniques. Consistent composition of matter based upon a given standard has been difficult to define. In addition, the method of quantifying and characterization of these commercially available materials has not been agreed upon within the industry. The end user, whether a researcher, a manufacturer, a marketing arm of industry or the consumer, should know that they are receiving a consistent product. A blind study of 32 various A. vera L. samples from different manufacturers, and a prepared sample of fresh A. vera L. gel with the commercial, biologic drug Acemannan Immunostimulanttrade mark, were analyzed for content of high molecular weight (polysaccharides) material by size exclusion chromatography with refractive index detection (SEC/RI) and SEC/RI coupled with multi-angle laser light scattering (MALLS) detection. Results from the SEC/RI analysis showed significant variation in the high molecular weight content, and the MALLS analysis also showed significant variation versus SEC/RI. In addition, HPLC analysis of the anthraquinone content showed that all samples contained significantly less than that of the raw, unwashed aloe gel. The variation of results from all analysis is attributed to differing methods in which the samples were processed by the different manufacturers.