UV-C irradiation disrupts platelet surface disulfide bonds and activates the platelet integrin alphaIIbbeta3

UV-C irradiation has been shown to be effective for pathogen reduction in platelet concentrates, but preliminary work indicated that UV-C irradiation of platelets can induce platelet aggregation. In this study, the mechanism underlying this phenomenon was investigated. Irradiation of platelets with UV-C light (1500 J/m(2)) caused platelet aggregation, which was dependent on integrin alphaIIbbeta3 activation (GPIIb/IIIa). This activation occurred despite treatment with several signal transduction inhibitors known to block platelet activation. UV-C also induced activation of recombinant alphaIIbbeta3 in Chinese hamster ovary (CHO) cells, an environment in which physiologic agonists fail to activate. Activation of alphaIIbbeta3 requires talin binding to the beta3 tail, yet alphaIIbbeta3-Delta724 (lacking the talin binding site) was activated by UV-C irradiation, excluding a requirement for talin binding. The UV-C effect appears to be general in that beta(1) and beta(2) integrins are also activated by UV-C. To explain these findings, we investigated the possibility of UV-C-induced photolysis of disulfide bonds, in analogy with the activating effect of reducing agents on integrins. Indeed, UV-C induced a marked increase in free thiol groups in platelet surface proteins including alphaIIbbeta3. Thus, UV-C appears to activate alphaIIbbeta3 not by affecting intracellular signal transduction, but by reduction of disulfide bonds regulating integrin conformation.     

Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.     

X-linked chronic granulomatous disease: correction of NADPH oxidase defect by retrovirus-mediated expression of gp91-phox

Chronic granulomatous disease (CGD) is an inherited immunodeficiency resulting from the inability of an individual's phagocytes to produce superoxide anions because of defective NADPH oxidase. The disease may be treated by bone marrow transplantation and as such is a candidate for somatic gene therapy. Two thirds of patients have defects in an X- linked gene (X-CGD) encoding gp91-phox, the large subunit of the membrane cytochrome b-245 component of NADPH oxidase. Epstein-Barr virus-transformed B-cell lines from patients with CGD provide a model system for the disease. We have used retrovirus-mediated expression of gp91-phox to reconstitute functionally NADPH oxidase activity in B-cell lines from three unrelated patients with X-CGD. The protein is glycosylated and membrane associated, and the reconstituted oxidase is appropriately activated via protein kinase C. The kinetics of superoxide production by such reconstituted cells is similar to that of normal B-cell lines. These data show the potential of gene therapy for this disease.     

A phase II study of continuous infusion recombinant human granulocyte- macrophage colony-stimulating factor as an adjunct to autologous bone marrow transplantation for patients with non-Hodgkin's lymphoma in first remission

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) clearly hastens myeloid recovery in patients with relapsed hematologic malignancies undergoing autologous bone marrow transplantation (ABMT). In efforts to further improve neutrophil engraftment and shorten hospital stay in ABMT patients, rhGM-CSF was administered by a potentially more potent route (continuous infusion) to non-Hodgkin's lymphoma (NHL) patients with better BM reserve (first remission). Time to myeloid engraftment was compared with that of NHL patients treated in first remission at our institution on a similar ABMT protocol but without growth factor support (controls). Median neutrophil engraftment (absolute neutrophil count, 500 cells/microL) in first remission patients treated with rhGM-CSF was 14 days, compared with 22 days in controls (P = .0001). Hospital stays were also significantly reduced for rhGM-CSF patients (P = .0003). Platelet engraftment did not differ between the two groups. Persistent fever and generalized serositis were the primary toxicities. rhGM-CSF, delivered by this route, was efficacious but more toxic than 2-hour rhGM-CSF infusions previously reported by other investigators. Future alterations in both dose and schedule may retain comparable efficacy yet diminish toxicity.     

Long term survival after pancreatic resection for pancreatic adenocarcinoma

OBJECTIVE: The aim of this study was to determine the long term survival of patients with pancreatic adenocarcinoma who underwent surgical resection and to assess the association of clinical, pathological, and treatment features with survival. METHODS: Between January, 1990, and December, 1998, 125 patients underwent a pancreaticoduodenal or partial pancreatic resection for pancreatic ductal adenocarcinoma at our institution. The records of these patients were reviewed for demographics, tumor characteristics including size, histological grade, margin status, lymph node status, surgical TNM staging, and postoperative adjuvant therapy. The primary outcome variable analyzed was survival. RESULTS: A total of 116 patients had complete follow-up and were included in the final analysis. The median survival after surgery was 16 months. The 1-, 3-, 5-, and 7-yr survival rates for all 116 patients were 60%, 23%, 19%, and 11%, respectively. The 1-, 3-, 5-, and 7-yr survival rates for patients who received adjuvant therapy were 69%, 28%, 23%, and 18% compared with 20% and 0% in patients who did not receive adjuvant therapy (p < 0.0001). The 1-, 3-, 5-, and 7-yr survival rates for patients with negative lymph nodes were 73%, 38%, 26%, and 22% compared with survival rates of 52%, 14%, 14%, and 9% in patients with positive lymph nodes (p = 0.01). In multivariate analyses, adjuvant therapy was the only feature found to be strongly associated with survival (hazards ratio = 0.26, 95% CI = 0.15-0.44). CONCLUSIONS: The overall 5- and 7-yr survival rates of 19% and 11% in our study further validate that surgical resection in patients with pancreatic adenocarcinoma can result in long term survival, particularly when performed in association with adjuvant chemoradiation.     

Congenital esophageal stenosis in adults

OBJECTIVE: Congenital esophageal stenosis is thought to be a rare disease confined to infancy and childhood with only a few case reports in adults described. METHODS: We report five patients between the ages of 19 and 46 yr who presented with this disorder over a 2-yr period. RESULTS: Patients had been labeled with reflux strictures, webs, or as idiopathic in the past. All patients had chronic solid food dysphagia, some since early childhood. The location of the stricture varied, occurring in the mid or proximal esophagus in four, but throughout the esophagus in one. Radiographic and endoscopic appearance was a smooth concentric stricture or multiple rings, sometimes tracheal in appearance. Endosonography was performed in two patients, both of whom had focal circumferential hypoechoic wall thickening with disruption of the normal layer pattern corresponding to the areas of luminal narrowing. All patients dilated had good symptomatic response, with resolution of symptoms up to 6 months in follow-up. CONCLUSIONS: We suggest that congenital esophageal stenosis does occur in adults and may be underrecognized. Its endosonographic appearance is described.     

The inflammatory reaction to crystals

Acute gout serves as a relatively well-defined paradigm for the review of the pathogenesis of acute microcrystal-induced inflammation. Inflammatory mediator systems activated directly or indirectly by urate crystals, the temporal events in a gouty paroxysm, and the possible factors responsible for the wide clinical variability of acute gout and other forms of crystal-induced inflammation are discussed.     

Fragile X‐associated tremor/ataxia syndrome (FXTAS) in grey zone carriers

The grey zone (GZ; 45–54 CGG repeats in the FMR1 gene) is considered a normal allele; however, several studies have found a high frequency of GZ in movement disordered populations. Here, we describe neurological features of fragile X‐associated tremor/ataxia syndrome (FXTAS) in two carriers of GZ alleles, although FXTAS has been defined as occurring only in premutation carriers (55–200 CGG repeats). Both patients had family members who had premutation and were diagnosed with FXTAS. The presence of relatively high GZ alleles with elevated fragile X mental retardation 1 mRNA (FMR1‐mRNA) combined with a family history of FXTAS that may represent a facilitating genetic background for FXTAS are the factors that led to the presence of FXTAS in these individuals with a GZ allele. Further research into clinical involvement of GZ alleles is recommended and the definition of FXTAS may require revision.     

Expression and function of CD40 on Hodgkin and Reed-Sternberg cells and the possible relevance for Hodgkin's disease

CD40 was originally described as a B-cell-restricted antigen and was subsequently found to be a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 is also expressed on dendritic cells, thymic epithelium, monocytes, and some carcinoma cell lines, and plays a critical role in cell contact-dependent activation. Primary and cultured Hodgkin and Reed-Sternberg (H-RS) cells, the presumed malignant cells of Hodgkin's disease (HD); were found to express high levels of cell surface CD40. We found that recombinant CD40 ligand (CD40L) induced interleukin-8 (IL-8) secretion and enhanced IL-6, TNF, and lymphotoxin-alpha (LT-alpha/TNF-beta) release from cultured H-RS cells. These cytokines play a significant role in the clinical presentation and pathology of HD, a tumor of cytokine-producing cells. CD40L had no mitogenic activity for HD-derived cell lines. In contrast, CD40L enhanced expression of costimulatory molecules intracellular adhesion molecule-T and B7-1 on cultured H-RS cells, both of which are overexpressed on primary H-RS cells. In addition, CD40L induced a 40% to 60% reduction of the expression of the HD-associated CD30 antigen, another member of the TNF receptor superfamily. Primary and cultured H- RS cells express not only CD30, but also CD40. CD40L has pleiotropic biologic activities on H-RS cells, and the CD40-CD40L interaction might be a critical element in the deregulated cytokine network and cell contact-dependent activation cascade typical for HD.