The fate of the open canalicular system in surface and suspension- activated platelets

We have examined the movement of fibrinogen-gold (fgn-Au) complexes in platelets activated in suspension and by surface contact. Fgn-Au probes did not react with resting cells but were bound to the external membrane of platelets in suspension 5 seconds after addition of 1 U/mL of thrombin. At intervals over a period of 5 to 20 minutes, fgn-Au probes moved from the cell surface to peripheral and then deep channels of the open canalicular system (OCS). When platelets were surface activated by exposure to carbon-stabilized, formvar-coated grids for 5 to 20 minutes and then exposed to fgn-Au complexes for 5 minutes, probes were also observed in the OCS. At 5 minutes, over 40% of the platelets had concentrated fgn-Au in their OCS. Results after 10 minutes revealed 25% with gold-filled channels, 16% after 15 minutes, and 5% after 20 minutes. The decrease in frequency of OCS staining correlated with the increasing frequency of spread platelets, suggesting that tension produced by spreading may cause collapse of the OCS or that the OCS may evaginate onto the platelet during spreading. To evaluate the latter hypothesis, platelets were initially exposed to grids for 5 minutes and then incubated with fgn-Au for intervals of 5 to 20 minutes. The frequency of platelets with fgn-Au concentrated in the OCS was greatest at 5 minutes (44%) and decreased at the same rate as the frequency of spread platelets increased. Only 14.7% of the cells contained fgn-Au in the OCS after 20 minutes. These were primarily dendritic in form, while fully spread platelets rarely contained an OCS filled with the probe. The study indicates that fgn-Au particles are cleared to channels of the OCS independent of the mechanism of platelet activation. Fgn-Au that has been concentrated in the OCS at early stages of surface activation can be externalized during platelet spreading but remain internalized in suspension-activated cells. The OCS represents a membrane reservoir that can be evaginated onto the platelet surface during interaction with surfaces.     

Gastroparesis in patients with inactive Crohn's disease: a case series

Background  

Few studies have described patients with foregut dysmotility in inflammatory bowel disease. The aim of this case series was to evaluate clinical characteristics of 5 patients with inflammatory bowel disease and symptoms and signs of upper gut dysmotility.     

Long-term management of gastro-oesophageal reflux disease with omeprazole or open antireflux surgery: results of a prospective, randomized clinical trial. The Nordic GORD Study Group

BACKGROUND AND AIM: The efficacy of antireflux surgery (ARS) and omeprazole treatment in the control of gastrooesophageal reflux disease (GORD) are well established. We have compared these two therapeutic options in a randomized, clinical trial. PATIENTS AND METHODS: Three hundred and ten patients with erosive oesophagitis were enrolled into the trial. After a run-in period when all patients had < or = 40 mg of omeprazole daily to heal the oesophagitis and relieve symptoms, 155 patients were randomized to continuous omeprazole therapy and 155 to open antireflux surgery, of whom 144 later had an operation. One hundred and thirty-nine and 129 in the omeprazole and antireflux surgery groups, respectively, completed the 3-year follow-up. Symptoms, 24-h pH monitoring and endoscopy were used to document the outcome. Quality of life was evaluated by the psychological general well-being (PGWB) index and the gastrointestinal symptom rating scale (GSRS). RESULTS: Analysis of time to treatment failure (defined as moderate to severe GORD symptoms for > or = 3 days during the last 7 days, oesophagitis or changed therapy) revealed a significant difference in favour of antireflux surgery (P = 0.0016). Seventeen patients originally submitted to antireflux surgery experienced symptom relapse alone, 14 had oesophagitis at endoscopy and another six had omeprazole for different reasons, leaving 97 patients in clinical remission after 3 years. The corresponding figures in the omeprazole arm were 50 relapses, 18 with oesophagitis, two had surgery, leaving 77 patients in remission. Allowing a dose adjustment in the case of relapse in those on omeprazole therapy to either 40 or 60 mg, the curves describing the failure rates were not significantly different from each other. Quality of life assessment showed a comparable outcome in the two study groups. CONCLUSION: In this randomized multicentre trial we found antireflux surgery to be very efficacious in controlling GORD, a level of control which could also be achieved by omeprazole provided that advantage was taken of the opportunity of adjusting the dose.     

Patients with endoscopic gastritis and/or duodenitis improve markedly following eradication of Helicobacter pylori,although less so than patients with ulcers

BACKGROUND: It is well documented that dyspepsia in patients with peptic ulcer disease (PUD) improves markedly after eradication of Helicobacter pylori, while rarely does it improve in patients with functional dyspepsia. There is a large group of H. pylori-infected patients who do not qualify for either diagnosis, but in whom eradication may be considered. The aim of this study was to compare symptom severity, change in gastrointestinal symptoms 1 year after eradication and satisfaction with therapy between PUD patients and patients with endoscopic diagnoses of gastritis and/or duodenitis (G/D patients). METHODS: The patients were randomized to one of four triple regimens containing ranitidine bismuth and metronidazole, and either oxytetracycline or spiramycine. Eradication was assessed with the 14C-urea breath test. GI symptoms were evaluated using the Gastrointestinal Symptom Rating Scale (GSRS) and the Ulcer Esophagitis Subjective Symptoms Scale (UESS) questionnaires. RESULTS: One-hundred-and-eighty-three patients were recruited from GI outpatient clinics. Patients with PUD and G/D had similar severity of symptoms before eradication therapy. One year after H. pylori eradication, 99% of the PUD patients and 75% of the G/D patients felt better regarding their main upper GI complaint. Abdominal pain score decreased by 48% as measured by GSRS and by 78% as measured by UESS in the PUD group and by 25% and 47%, respectively, in the G/D group. Reflux symptoms decreased by 41% and 63% in PUD patients and by 28% and 45% in G/D patients; indigestion by 30% and 47% in PUD and by 20% and 34% in G/D; eating discomfort by 60% in PUD and by 35% in G/D. Sleep quality score improved by 68% in PUD and by 41% in NU patients. Constipation decreased by 22% in the PUD group. All these differences in symptoms were highly significant compared to baseline. Diarrhoea was unchanged. CONCLUSIONS: Abdominal pain, reflux symptoms, indigestion and the ability to eat and sleep improved in both PUD and G/D patients 1 year after H. pylori eradication. Chronic diarrhoea was not induced. Abdominal pain improved significantly more in PUD than in G/D patients. Further study of the effect of H.pylori eradication in G/D patients is warranted.     

Diverging associations of an intended early invasive strategy compared with actual revascularization, and outcome in patients with non-ST-segment elevation acute coronary syndrome: the problem of treatment selection bias

AIMS: In several observational studies, revascularization is associated with substantial reduction in mortality in patients with non-ST-segment elevation acute coronary syndrome (nSTE-ACS). This has strengthened the belief that routine early angiography would lead to a reduction in mortality. We investigated the association between actual in-hospital revascularization and long-term outcome in patients with nSTE-ACS included in the ICTUS trial. METHODS AND RESULTS: The study population of the present analysis consists of ICTUS participants who were discharged alive after initial hospitalization. The ICTUS trial was a randomized, controlled trial in which 1200 patients were randomized to an early invasive or selective invasive strategy. The endpoints were death from hospital discharge until 4 year follow-up and death or spontaneous myocardial infarction (MI) until 3 years. Among 1189 patients discharged alive, 691 (58%) underwent revascularization during initial hospitalization. In multivariable Cox regression analyses, in-hospital revascularization was independently associated with a reduction in 4 year mortality and 3 year event rate of death or spontaneous MI: hazard ratio (HR) 0.59 [95% confidence interval (CI) 0.37-0.96] and 0.46 (95% CI 0.31-0.68). However, when intention-to-treat analysis was performed, no differences in cumulative event rates were observed between the early invasive and selective invasive strategies: HR 1.10 (95% CI 0.70-1.74) for death and 1.27 (95% CI 0.88-1.85) for death or spontaneous MI. CONCLUSION: The ICTUS trial did not show that an early invasive strategy resulted in a better outcome than a selective invasive strategy in patients with nSTE-ACS. However, similar to retrospective analyses from observational studies, actual revascularization was associated with lower mortality and fewer MI. Whether an early invasive strategy leads to a better outcome than a selective invasive strategy cannot be inferred from the observation that revascularized patients have a better prognosis in non-randomized studies.     

Studies investigating platelet aggregation and release initiated by sera from patients with thrombotic thrombocytopenic purpura

Many patients with thrombotic thrombocytopenic purpura (TTP) have a platelet aggregating factor in their serum that may be pathologically linked with the disease process. To help characterize the type of platelet aggregation and platelet release induced by the sera from seven TTP patients, we measured the ability of a variety of inhibitors of platelet function as well as the ability of monoclonal antibodies (MoAbs) against platelet glycoproteins to inhibit TTP sera-induced platelet aggregation and release. These results were compared with the ability of the same inhibitors to block platelet aggregation induced by ristocetin, collagen, ADP, thrombin, and IgG-immune complexes. Monoclonal antibody directed against platelet glycoprotein Ib totally inhibited ristocetin-induced aggregation and release but had no effect on aggregation and release induced by the TTP sera or by any of the other platelet agonists. However, the MoAb against glycoproteins IIb/IIIa inhibited aggregation and release caused by TTP sera as well as by collagen, thrombin, and ADP but had no effect on aggregation and release induced by ristocetin. The aggregating activity could be abolished by heparin but not by the serine protease inhibitor PMSF (1 mmol/L). And although monomeric human IgG and purified Fc fragments of IgG inhibited IgG-immune complex-induced aggregation and release, they had no effect on TTP sera-induced aggregation and release nor on aggregation and release induced by any of the other agonists. Consistent with these in vitro studies showing no effect of IgG were the in vivo observations that intravenous (IV) IgG was without effect when administered to three patients with TTP. This study indicates that although a von Willebrand factor (vWF)-rich preparation of cryoprecipitate enhances the in vitro platelet aggregation and release caused by sera from the seven TTP patients we studied, the pathway of aggregation and release is not via platelet glycoprotein Ib. Also the aggregating factor of TTP sera is not neutralized in vitro or in vivo by IgG.     

Calcium-dependent cysteine protease activity in the sera of patients with thrombotic thrombocytopenic purpura

Plasma and serum from patients with thrombotic thrombocytopenic purpura (TTP) can cause activation and aggregation of normal human platelets in vitro. It is possible that this platelet-activating factor contributes to the disease. In this report we describe studies designed to identify the platelet-activating factor in TTP. Platelet activation by sera from 15 patients with TTP was inhibited by leupeptin, iodoacetamide, and antipain but not by phenylmethylsulphonylfluoride, epsilon-aminocaproic acid, soybean trypsin inhibitor, aprotinin, and D-phenylanyl-1-prolyl-1- arginine chloromethyl ketone. These studies suggested that the platelet- activating factor in TTP serum was a cysteine protease. We confirmed that a calcium-dependent cysteine protease (CDP) was present in the sera of each of the 15 patients when we used an assay based on the ability of CDP to proteolyse platelet membrane glycoprotein 1b (GP1b) and hence to abolish the ability of CDP-treated normal platelets to agglutinate in the presence of ristocetin and von Willebrand factor. This proteolytic activity was inhibited by EDTA, leupeptin, antipain, iodoacetamide, and by N-ethyl-maleamide (NEM) but not by the serine protease inhibitors. Activity was detected in 15 of 15 patients with TTP tested before therapy was begun. In contrast, no activity was detected in the serum of any of five of the TTP patients tested in remission or in any of the sera from 36 patients with thrombocytopenia and 423 nonthrombocytopenic controls. To look for in vivo CDP activity in patients with TTP, we studied platelets from two patients with acute TTP (drawn into acid-citrate-dextrose, NEM, and leupeptin). These platelets showed a loss of GP1b from the platelet surface. Both patients were also studied in remission: GP1b on the platelet surface had returned to normal. These studies provide evidence that CDP is present in the sera of patients with TTP, that it is specific to this disease, and that is is active in vivo as well as in vitro. We postulate that a disorder of CDP homeostasis plays a major role in the pathophysiology of TTP.     

Development of large numbers of mast cells at sites of idiopathic chronic dermatitis in genetically mast cell-deficient WBB6F1-W/Wv mice

The normal skin and other tissues of adult mast cell-deficient WBB6F1- W/Wv or WCB6F1-Sl/Sld mice contain less than 1.0% the number of mast cells present in the corresponding tissues of the congenic normal (+/+) mice. As a result, genetically mast cell-deficient WBB6F1-W/Wv or WCB6F1-Sl/Sld mice are widely used for studies of mast cell differentiation and function. We found that mast cells developed at sites of idiopathic chronic dermatitis in WBB6F1-W/Wv mice and that the number of mast cells present in the skin of WBB6F1-W/Wv mice was proportional to the severity of the dermatitis (in ear skin, there were 33 +/- 4 mast cells/mm2 of dermis at sites of severe dermatitis v 9 +/- 3 at sites of mild dermatitis, 0.8 +/- 0.3 in skin without dermatitis, and 100 +/- 7 in the normal skin of congenic WBB6F1-+/+ mice; in back skin, the corresponding values were 2.0 +/- 0.6, 1.1 +/- 0.9, 0.025 +/- 0.025, and 26.2 +/- 3.2). The development of mast cells was a local, not systemic, consequence of the dermatitis. Thus, WBB6F1-W/Wv mice with severe dermatitis lacked mast cells in skin not showing signs of dermatitis and also in the peritoneal cavity, stomach, cecum, and tongue. Idiopathic chronic dermatitis was not associated with the local development of mast cells in WCB6F1-Sl/Sld mice, a mutant whose mast cell deficiency is due to a mechanism distinct from that of WBB6F1-W/Wv mice. These findings may have implications for understanding the nature of the mast cell deficiency in WBB6F1-W/Wv and WCB6F1-Sl/Sld mice and for the use of these mutants to analyze mast cell differentiation and function.     

CML patients in blast crisis have breakpoints localized to a specific region of the BCR

Chronic myelogenous leukemia (CML) is associated with the Philadelphia (Ph) chromosome, which results from a reciprocal translocation between chromosomes 9 and 22. This activates the abl oncogene by moving it from chromosome 9 and combining it with sequence located on chromosome 22. The new fusion gene, with chromosome 22 sequence at its 5' end and chromosome 9-abl sequence at its 3' end, generates a new messenger RNA (mRNA) and protein that are implicated in the pathogenesis of CML. The breakpoint near the c-abl locus on chromosome 9 can occur within a large area. In contrast, the breakpoints on chromosome 22 are concentrated within a 6 kilobase (kb) region termed the breakpoint cluster region (bcr). This study was designed to determine whether chronic-phase and blast crisis patients had identifiable differences in the structure of their Ph chromosomes. Restriction mapping of the chromosome 22 translocation breakpoints performed for 26 patients showed that the breakpoints of eight of the nine patients in blast crisis were in the 3' portion of the bcr, whereas the breakpoints in the 17 patients in the chronic phase were clustered in the 5' portion of the bcr. This suggests a strong correlation between a 3' bcr breakpoint and blast crisis in CML.