Platelet adhesion to collagen types I through VIII under conditions of stasis and flow is mediated by GPIa/IIa (alpha 2 beta 1-integrin)

Platelet adhesion to fibrillar collagens (types I, II, III, and V) and nonfibrillar collagens (types IV, VI, VII, and VIII) was investigated in the presence of physiologic concentrations of divalent cations under conditions of stasis and flow. Under static conditions, platelet adhesion was observed to collagen types I through VII but not to type VIII. Under flow conditions, platelet adhesion to collagen types I, II, III, and IV was almost independent of shear rates above 300/s. Collagen type V was nonadhesive. Platelet adhesion to collagen type VI was shear rate-dependent and optimal at a rate of 300/s. Collagen types VII and VIII showed minor reactivity and supported platelet adhesion only between shear rates 100 to 1,000/s. Monoclonal antibody (MoAb) 176D7, directed against platelet membrane glycoprotein Ia (GPIa; very late antigen [VLA]-alpha 2 subunit), completely inhibited platelet adhesion to all collagens tested, under conditions of both stasis and flow. Platelet adhesion to collagen type III at shear rate 1,600/s was only inhibited for 85%. The concentration of antibody required for complete inhibition of platelet adhesion was dependent on the shear rate and the reactivity of the collagen. An MoAb directed against GPIIa (VLA-beta subunit) partially inhibited platelet adhesion to collagen. These results show that GPIa-IIa is a major and universal platelet receptor for eight unique types of collagen.     

Extracranial tumor vascularity: determination by dynamic CT scanning. Part II: The unit approach

Twenty-eight patients had combined conventional drip infusion CT scans. The information about the anatomic location of the lesion, its configuration, its cross-sectional appearance, its vascularity (as determined by dynamic signature curves), and its clinical presentation were considered as a single overall unit. This diagnostic approach allowed a diagnosis to be made on virtually all of these enhancing lesions without resorting to either a digital venous imaging study or angiographic procedure. In 17 of these cases, such an invasive second procedure was performed either to confirm the CT impression as part of this study or as part of a therapeutic embolization procedure.     

玻片法单人份免疫分型试剂盒在白血病诊断中的应用

0引言白血病免疫分型是指用已知的单克隆抗体(单抗)鉴定细胞表面或胞质内的分化抗原的方法.该方法的临床应用有利于白血病的鉴别及诊断.我们采用单人份免疫分型试剂盒对128例白血病患者进行了免疫分型.     

Histopathological changes in the oesophageal mucosa in Egyptian children with corrosive strictures: A single-centre vast experience

BACKGROUND The caustic ingestion continues to be a major problem worldwide especially in developing countries. The long-term complications include stricture and increased life time risk of oesophageal carcinoma. Patients suffered from corrosive induced oesophageal strictures have more than a 1000-fold risk of developing carcinoma of the oesophagus.AIM To determine the possibility of oesophageal mucosal dysplasia after prolonged dilatation in post corrosive stricture.METHODS This observational study was conducted at the Paediatric Endoscopy Unit in Cairo University Children's Hospital. It included children of both sexes older than 2 years of age who had an established diagnosis of post-corrosive oesophageal stricture and repeated endoscopic dilatation sessions for more than 6 mo. All patients were biopsied at the stricture site after 6 mo of endoscopic dilatation. A histopathological examination of an oesophageal mucosal biopsy was performed for the detection of chronic oesophagitis, inflammatory cellular infiltration and dysplasia.RESULTS The mean age of the enrolled children was 5.9 ± 2.6 years; 90% of the patients had ingested an alkaline corrosive substance(potash). The total number of endoscopic dilatation sessions were ranging from 16 to 100 with mean number of sessionswas 37.2 ± 14.9. Histopathological examination of the specimens showed that 85%of patients had evidence of chronic oesophagitis(group A) in the form of basal cell hyperplasia, hyperkeratosis and subepithelial fibrosis. Thirteen percent of the patients had evidence of reactive atypia(group B) in the form of severe neutrophilic intraepithelial inflammatory cellular infiltration, and 2 patients(2%)had mild squamous dysplasia(group C); we rebiopsied these two patients 6 mo after the initial pathological assessment, guided by chromoendoscopy by Lugol's iodine.CONCLUSION The histopathology of oesophageal mucosal biopsies in post-corrosive patients demonstrates evidence of chronic oesophagitis, intraepithelial inflammatory cellular infiltration and dysplasia. Dysplasia is one of the complications of postcorrosive oesophageal stricture.     

FC04.6Characterisation of dendritic cell responses to ascaridol, an autoxidation product of tea tree oil

A large number of monoterpenes and their degradation products are likely skin sensitizing agents (Hausen et al., 1999). Terpenes are very common e.g., as constituents of cosmetics, food and other daily used products.
We investigated responses to the endoperoxide 1,4‐epidioxy‐2‐p‐menthen (ascaridol), an autoxidation product of tea tree oil, using monocyte derived dendritic cells (MDDC). Therefore, we isolated peripheral blood mononuclear cells (PBMC) from 9 healthy donors by the standard Ficoll‐Paque gradient centrifugation.
Monocytes were isolated by adherence and incubated in media (RPMI 1640) containing GM‐CSF (800 units/ml), IL‐4 (1000 units/ml) and 10% autologous serum. The immature MDDC (day 6) were characterized by flow cytometry (CD1a+, CD14−, CD40, CD45, CD80, CD83, CD86, HLA‐DR and CCR‐7) and incubated with various concentrations of ascaridol (1–70 μg/ml). After one hour incubation time LPS was added (1 μg/ml) for 23 h. Cell culture supernatants were collected after 24 h for cytokine analysis.
IL‐12p40, IL‐12p70 and prostaglandin E2 were measured by ELISA, TNF‐alpha and IL‐2 were measured by flow cytometry (FACS). Methods of the quantification of steady state mRNA levels were established for IL‐12 and CCR7 (real‐time RT‐PCR). Ascaridol enhanced significantly IL‐12p70 production (120% up to 396%) by MDDC as well as mRNA levels for IL‐12 and CCR7. Moreover, we detected a distinct increase of TNF‐alpha (110% up to 146%) secretion, IL‐2 (135%) and PGE2 (102% up to 155%).
Totally, these results suggest that ascaridol may be a potent modulator of maturation and antigen presenting function of dendritic cells, and we performing further experiments to verify this hypothesis.
This study was supported by the Deutsche Forschungsgemeinschaft.