Variability of cut-off values for the detection of lupus anticoagulants: results of an international multicenter multiplatform study.

Essentials Between-lab variations of cut-off values in lupus anticoagulant detection are unknown. Cut-off values were calculated in 11 labs each testing plasma from 120 donors with 3 platforms. Major variation was observed even within the same platform. Cut-off values determined in different labs are not interchangeable. SUMMARY: Background Cut-off values for interpretation of lupus anticoagulant (LA) detection are poorly investigated. Aims (i) To assess whether results from healthy donors were normally distributed and (ii) the between-laboratories differences in cut-off values for screening, mixing and LA confirmation when calculated as 99th or 95th centiles, and (iii) to assess their impact on the detection rate for LA. Methods Each of 11 laboratories using one of the three widely used commercial platforms for LA detection was asked to collect plasmas from 120 healthy donors and to perform screening, mixing and LA confirmation with two methods (activated partial thromboplastin time [APTT] and dilute Russell viper venom [dRVV]). A common set of LA-positive or LA-negative freeze-dried plasmas was used to assess the LA detection rate. Results were centralized (Milano) for statistical analysis. Results and conclusions (i) Clotting times or ratios for healthy subjects were not normally distributed in the majority of cases. The take-home message is that cut-off values should be determined preferably by the non-parametric method based on centiles. (ii) There were relatively large inter-laboratory cut-off variations even within the same platform and the variability was marginally attenuated when results were expressed as ratios (test-to-normal pooled plasma). The take-home message is that cut-off values should be determined locally. (iii) There were differences between cut-off values calculated as 99th or 95th centiles that translate into a different LA detection rate (the lower the centile the greater the detection rate). The take-home message is that cut-off values determined as the 95th centile allow a better LA detection rate.

Feasibility and effectiveness of primary umbilical hernia repair with biologic graft: preliminary study.

BACKGROUND: In this prospective non-randomized observational cohort study we evaluated: the feasibility and effectiveness of primary umbilical hernia repair with open tension-free and sutureless technique using a porcine small intestinal submucosa (Surgisis) prosthesis, the quality of the treatment in terms of reduction of postoperative discomfort and the complications at early and long-term follow-up. METHODS: Thirty-six consecutive patients, mean age 45.25 +/- 12.19 years, affected by primary umbilical uncomplicated hernia with a defect size < or = 3 cm, were treated in a day-surgery setting. A tailored flat Surgisis graft was used to ensure an overlap of at least 2 cm; in all patients the mesh was fixed by fibrin glue. Collected data included: visual analogic scale (VAS) pain scores at 24 hours, 72 hours, and 7, 15, and 30 days and number of analgesic medications after operation, complications rate, the quality of life measured by Short Form 36 health survey questionnaire (SF-36) before the operation and at long term follow-up. RESULTS: The mean follow-up time was 5.6 +/- 1.4 years. Postoperative pain was low: the mean visual analogic scale (VAS) scores were 2.8 at 24 h, 1.8 at 72 h, and 0.9, 0.3, and 0.04 at 7, 15, and 30 days, respectively. 77.8% of the patients (28/36) did not use any analgesic drugs. Seroma was reported in 13.8% of the patients (5/36); there were no hematomas, infection, chronic pain and no major complications or mortality (< or = 30 days). Recurrence rate was 2.8% (1/36). Patient satisfaction showed a significant improvement in all SF-36 domain scores (P < 0.001). CONCLUSIONS: The biologic mesh seems to be a safe and reliable device for repairing primary umbilical hernia with high patient comfort, even if not yet an alternative to synthetic mesh.

Whole blood rotation thromboelastometry (ROTEM(®)) in nine severe factor V deficient patients and evaluation of the role of intraplatelets factor V.

Severe factor V (FV) deficiency (parahaemophilia) is a rare congenital hemorrhagic disorder characterized by very low or undetectable plasma FV levels and bleeding phenotype ranging from mild to severe. We evaluated whole blood (WB) rotation thromboelastometry (ROTEM) in parahaemophilia patients and the contribution of intraplatelets FV, if any, to clot formation. Standard ROTEM(®) assays were performed in WB from nine parahaemophilia patients and 50 healthy controls. In addition, platelets poor plasma from one parahaemophilia patient (PPP-Pt) or normal subjects (PPP-N) was reconstituted with washed platelets obtained either from one patient with parahaemophilia (Plts-Pt) or normal subjects (Plts-N) and ROTEM assays were performed in platelets rich plasma (PRP) samples. There was a prolongation of the WB clotting time (CT) in all assays in patients as compared with controls. However, maximum clot firmness (MCF) was similar in patients and controls. ROTEM in PPP-Pt showed both a prolongation of CT and a reduction of MCF as compared with PPP-N. The addition of either Plts-Pt or Plts-N to PPP-Pt resulted in similar increase in MCF and a decrease of CT which was more evident for PPP-Pt + Plts-N than PPP-Pt + Plts-Pt. In contrast, the addition of Plts-Pt or Plts-N to PPP-N had superimposable effects on both CT and MCF. In parahaemophilia patients, WB ROTEM(®) presents mainly with prolongation of CT and no relevant effect on MCF. Residual intraplatelets FV in parahaemophilia contributes significantly to thrombin generation as shown in artificially reconstituted PRP models.

On the mechanism of the spermine-exerted inhibition on alpha-thrombin-induced platelet activation.

Previous reports have shown that various amines inhibited platelet activation, but no definitive conclusions on their action mechanism were drawn. We have further investigated the action of spermine on platelet responses evoked by alpha-thrombin and other agonists. Spermine inhibited in a concentration-dependent manner (1-10 mM), and more efficiently than spermidine and putrescine, the alpha-thrombin-induced (1.5 nM) platelet activation. Spermine added at a concentration that inhibited completely aggregation only partially affected the thrombin-induced increase in cytosolic Ca(2+) concentration, protein phosphorylation, and ATP secretion. The polyamine had little effect on the morphology of resting platelets, as measured by electron microscopy, thrombin hydrolytic activity, and fibrinogen clotting capacity but decreased the thrombin binding to platelets and isolated glycocalicin. Spermine partially inhibited the aggregation elicited by ADP, vasopressin, platelet-activating factor, thrombin receptor-activating peptide, fluoroaluminate, ionomycin, and dioctanoylglycerol but did not affect the cytosolic Ca(2+) increase induced by these agonists. The polyamine bound to both glycocalicin and platelets, and it inhibited the fibrinogen binding to stimulated platelets. The amount of 14C-spermine bound to resting cells decreased in the presence of the glycoprotein GPIb-antibody LJIB1, whereas the polyamine bound to activated platelets, which was higher than that tied to resting cells, was markedly reduced by LJCP8 or decorsin, a GPIIb/IIIa antibody and antagonist-peptide, respectively. These results indicate that spermine specifically inhibits the thrombin binding to GPIb of resting platelets and the fibrinogen binding to GPIIb/IIIa (integrin alpha(IIb)beta(3)) of activated platelets.

[Usefulness of chromogranin A determination in the diagnosis of neuroendocrine neoplasia]. / Utilità del dosaggio della cromogranina A nella diagnosi delle neoplasie neuroendocrine.

Neuroendocrine gastroenteropancreatic tumor diagnosis is a very difficult and expensive procedure. This study compared Chromogranin A (CgA) to Neuron-specific enolase (NSE) in 55 patients affected by neuroendocrine tumors. Advanced local or metastatic neoplasia was found in 43 patients. Radical operation was performed in 12 patients. Seventeen cases of lung microcystoma, 23 cases of other intestinal tumors and 19 patients affected by irritable bowel syndrome were used as controls. CgA sampling demonstrated sensitivity of 73% and specificity of 66%, a positive predictive value of 77% and a negative predictive value of 61% while NSE sampling showed sensitivity of 100%, specificity of 36%, a positive predictive value of 15% and a negative predictive value of 100%. CgA values demonstrated a statistically significant difference between patients with neuroendocrine tumors and tumor-free resected patients (p = 0.0015), microcystoma patients (p = 0.0087), other types of neoplasia (p = 0.01) and irritable bowel syndrome patients (p = 0.0004). No significant difference was found among the same groups when NSE values were analyzed. The high diagnostic accuracy of CgA sampling renders it very useful in early neoplastic detection, even in cases of nonfunctioning neoplasms or absence of liver metastases. In addition, CgA sampling may be an effective screening test in patients with irritable bowel syndrome or with liver or lung metastases when there is no evidence of the primitive tumor.

IgG platelet antibodies in EDTA-dependent pseudothrombocytopenia bind to platelet membrane glycoprotein IIb.

EDTA-dependent pseudothrombocytopenia (PTCP) consists of an inappropriate low platelet count caused by autoantibodies present in the serum samples reacting with platelets only in EDTA-anticoagulated blood. By using immunoprecipitation and Western blot techniques, we studied the immunochemical specificity of platelet agglutinating autoantibodies in the serum samples of 10 patients with PTCP. Furthermore, to evaluate a possible role of PTCP-associated IgG autoantibodies in increased platelet turnover, we assayed the plasma glycocalicin (GC) level and calculated the GC index for every patient. Our results provide direct evidence that an epitope located on platelet membrane glycoprotein IIb is recognized by PTCP-associated IgG antibodies; moreover GC levels in patients with EDTA-dependent PTCP were similar to control levels, thus excluding an increased platelet turnover. We conclude that antiplatelet antibodies directed against platelet cryptantigens are unlikely to have a major role in the increased removal of cells from circulation.

Glycocalicin in the diagnosis and management of immune thrombocytopenia.

We studied glycocalicin (GC), expressed as plasma GC concentration and as GC index (ratio to platelet count), in 129 thrombocytopenic patients (platelet count < 100 x 10(9)/l) and 60 sex- and age-matched controls. Seventy-two patients had idiopathic immune thrombocytopenia, 32 secondary immune thrombocytopenia, 8 microangiopathic thrombocytopenia and 17 thrombocytopenia secondary to bone marrow aplasia. Patients with immune thrombocytopenia (ITP) were also subclassified, according to their clinical behaviour, as having active disease or being in spontaneous or therapy-induced partial remission. A significant correlation was found between glycocalicin levels and platelet count both in normals and in patients with bone marrow aplasia (r = 0.75). ITP patients showed a GC index significantly higher than controls (6.02+/-7.87 vs. 0.9+/-0.2, p<0.001). When ITP patients with similar platelet count (30-50 x 10(9)/l) were studied, the mean level of GC and the GC index were significantly higher in those patients with active disease than in those in remission (0.97+/-0.38 vs. 0.58+/-0.17 microg/ml, p <0.05; 6.41+/-2.64 vs. 3.44+/-0.94, p<0.05, respectively). A longitudinal study performed in 10 patients with different subtypes of ITP suggested a positive correlation between GC index and the activity of the disease. The GC value and GC index were significantly higher in patients with microangiopathic thrombocytopenia than in controls (1.44+/-0.73 vs. 0.8+/-0.16 microg/ml, p < 0.01; and 18.77+/-22.23 vs. 0.9+/-0.2, p<0.001, respectively). The GC value was significantly lower in bone marrow failure (0.15+/-0.04 microg/ml, p<0.01) compared to controls, while no difference was observed in the GC index. Our data confirm that the GC index is helpful in differentiating thrombocytopenia due to increased platelet destruction from the one due to impaired production. In addition, the assay has been proven useful in the differential diagnosis of different ITP subtypes and their follow-up.

Characterization of the initial alpha-thrombin interaction with glycoprotein Ib alpha in relation to platelet activation.

We have evaluated the properties of alpha-thrombin interaction with platelets within 1 min from exposure to the agonist, a time frame during which most induced activation responses are initiated and completed. Binding at 37 degrees C was rapidly reversible and completely blocked by a monoclonal antibody, LJ-Ib10, previously shown to be directed against the alpha-thrombin interaction site on glycoprotein (GP) Ib alpha. By 2-5 min, however, binding was no longer fully reversible and was only partially inhibited by the anti-GP Ib alpha antibody. Results were similar at room temperature (22-25 degrees C), whereas the initial characteristics of alpha-thrombin interaction with platelets were preserved for at least 20 min at 4 degrees C. Equilibrium binding isotherms obtained at the latter temperature were compatible with a two-site model, but the component ascribed to GP Ib alpha, completely inhibited by LJ-Ib10, had "moderate" affinity (kd on the order of 10(-8) M) and relatively high capacity, rather than "high" affinity (kd on the order of 10(-10) M) and low capacity as currently thought. The parameters of alpha-thrombin binding to intact GP Ib alpha on platelets at 4 degrees C corresponded closely to those measured with isolated GP Ib alpha fragments regardless of temperature. Blocking the alpha-thrombin-GP Ib alpha interaction caused partial inhibition of ATP release and prevented the association with platelets of measurable proteolytic activity. These results support the concept that GP Ib alpha contributes to the thrombogenic potential of alpha-thrombin.

An original method to study autoantibody specificity in haemoglobin stained eluates by the column agglutination techniques.

When studying autoantibody specificity by the indirect antiglobulin test with column agglutination techniques ether and xylene elution techniques result in haemoglobin stained eluates which give a red colouration to the gel or glass beads and do not allow the identification of positive reactions. Xylene eluates were incubated with commercially available group O-test red cell panels at 37 degrees C for 45 min in the wells of a microtitre plate in a 3:1 eluate:red cell ratio. After washing with normal saline, sensitized red cells, resuspended in low ionic strength solution (LISS), were applied onto the microtubes containing the antiglobulin serum and positive reactions were recorded after centrifugation. We studied the specificity of 35 autoantibody containing eluates from 12 patients with lymphoproliferative disorders (six having autoimmune haemolysis) and 23 HIV patients without autoimmune haemolysis. All patients had a gel or column positive (IgG) direct antiglobulin test while the tube direct antiglobulin test failed to show red cell bound IgG. We found a reactive indirect antiglobulin test in 20/23 eluates from HIV infected patients (with a panreactive specificity), in all patients with autoimmune haemolysis (one with anti-C, two with anti-E, one with anti-K and two with a panreactive specificity) and in all patients with positive direct antiglobulin test but without immune mediate haemolysis (in all cases with panreactive specificity). The method proposed is a promising tool for the study of the specificity of antibody containing haemoglobin stained eluates; in this study it allowed us to confirm that some HIV patients have specific binding of IgG on their RBC and to identify the specificity of tube test non-reactive eluates.

Abnormalities of membrane protein composition in patients with autoimmune haemolytic anaemia.

Acquired abnormalities of red cell membrane protein composition in 37 patients with a positive direct antiglobulin test have been studied: 17 patients had true autoimmune haemolytic anaemia and 20 were HIV-infected subjects with a positive direct antiglobulin test but without signs of haemolysis. The study was carried out by performing sodium dodecyl sulphate polyacrylamide gel electrophoresis of ghost proteins followed by densitometric evaluation of the areas under the peaks, normalized by the total (alpha + beta) spectrin content. Results show a significant decrease of bands 3, 4.1 and 4.2 over spectrin in patients with autoimmune haemolysis as compared to controls; at least in a small subset of patients, different specificities recognized by autoantibodies do not seem to account for these abnormalities which are reproducible independently from the molecular size of bands immunoprecipitated by autoantibodies. A similar decrease of protein 4.2 but not of band 3 staining intensity is also noticeable in HIV patients with a positive direct antiglobulin test. These results are consistent with the hypothesis that, following interactions between autoantibodies and autoantigens, modifications occur on membrane proteins resembling a variety of quantitative defects described in inherited haemolytic anaemias, and mainly the "vertical interaction defects' of hereditary spherocytosis. Moreover, the decrease of band 3 staining intensity seems to represent a feature of patients with immune mediated haemolysis and not only with autoantibody binding.

Frequency and functional relevance of genetic threonine145/methionine145 dimorphism in platelet glycoprotein Ib alpha in an Italian population.

BACKGROUND: Threonine145/methionine145 dimorphism in platelet glycoprotein (GP) Ib alpha defines the human platelet antigen (HPA)-2 system that has been implicated in refractoriness to HLA-matched platelet transfusion and in neonatal immune thrombocytopenic purpura. STUDY DESIGN AND METHODS: The occurrence of this amino acid dimorphism was investigated in 379 Italian blood donors by studying their genomic DNA. Two oligonucleotide primers, Ib alpha-3 (5'-GGACGTCTCCTTCAACCGGC-3') and Ib alpha-4 (5'-GCTTTGGTGGGGAACTTGAC-3'), were used in a polymerase chain reaction to generate a 591-base pair fragment that was digested with the restriction enzyme Acy I. To investigate whether this dimorphism is involved in the binding of von Willebrand factor (vWF) to GPlb, the binding of vWF to the GPlb/IX complex was measured in two Met145/Met145 and two Thr145/Thr145 subjects. RESULTS: The genotypic frequencies are 78.9% for Thr/Thr, 19.8% for Thr/Met), and 1.3% for Met/Met; the allelic frequencies are 88.8% for Thr145 and 11.2% for Met145. Estimates for binding of subunit molecules per platelet at saturation and inhibition constant in mol per L, respectively, follow. In the presence of ristocetin (0.5 mg/mL), they are 11,460 +/- 2,040 and 1.26 +/- 0.44 x 10(-8) for normals and 11,230 +/- 2,330 and 1.29 +/- 0.48 x 10(-8) for patients. In the presence of botrocetin (2.5 micrograms/mL), they are 64,260 +/- 7,760 and 2.99 +/- 0.96 x 10(-8) for normals and 65,770 +/- 11,570 and 2.47 +/- 0.22 x 10(-8) for patients. Platelet aggregation responses obtained using platelet-rich plasma from donors with Met145/Met145 or Thr145/Thr145 genotype were within normal limits. CONCLUSION: Genotypic and phenotypic frequencies in the HPA-2 system in this population are consistent with those reported among the white population. Furthermore, the HPA-2 system is not involved in the binding of vWF to GPlb.

Porcine von Willebrand factor binding to human platelet GPIb induces transmembrane calcium influx.

Porcine von Willebrand factor (P-vWF) binds to human platelet glycoprotein (GP) Ib and, upon stirring (1500 rpm/min) at 37 degrees C, induces, in a dose-dependent manner, a transmembrane flux of Ca2+ ions and platelet aggregation with an increase in their intracellular concentration. The inhibition of P-vWF binding to GP Ib, obtained with anti GP Ib monoclonal antibody (LJ-Ib1), inhibits the increase of intracellular Ca2+ concentration ([Ca2+]i) and platelet aggregation. This effect is not observed with LJ-Ib10, an anti GP Ib monoclonal antibody which does not inhibit the vWF binding to GP Ib. An anti GP IIb-IIIa monoclonal antibody (LJ-CP8) shown to inhibit the binding of both vWF and fibrinogen to the GP IIb-IIIa complex, had only a slight effect on the [Ca2+]i rise elicited by the addition of P-vWF. No inhibition was also observed with a different anti GP IIb-IIIa monoclonal antibody (LJ-P5), shown to block the binding of vWF and not that of fibrinogen to the GP IIb-IIIa complex. PGE1, apyrase and indomethacin show a minimal effect on [Ca2+]i rise, while EGTA completely blocks it. The GP Ib occupancy by recombinant vWF fragment rvWF445-733 completely inhibits the increase of [Ca2+]i and large aggregates formation. Our results suggest that, in analogy to what is seen with human vWF under high shear stress, the binding of P-vWF to platelet GP Ib, at low shear stress and through the formation of aggregates of an appropriate size, induces a transmembrane flux of Ca2+, independently from platelet cyclooxygenase metabolism, perhaps through a receptor dependent calcium channel. The increase in [Ca2+]i may act as an intracellular message and cause the activation of the GP IIb-IIIa complex.

[Bilateral breast carcinoma. 12 years' experience]. / Carcinoma mammario bilaterale. Dodici anni di esperienza.

In order to assess bilateral breast carcinoma (BBC) clinical findings, 19 BBC cases were enrolled in succession (1982-1993). Of these, 7 (1.6%) had synchronous breast carcinomas and 12 (2.7%) had metachronous breast carcinomas. The occurrence of BBC was of 4.3% of women with breast cancer. The median age of the patients was 63.7 years for synchronous cancers and 53.5% for metachronous. Synchronous carcinomas were found symmetrically located in 42.5% of cases and metachronous in 58.3%. The most frequent location was in the upper outer quadrant (UOQ): 50% in synchronous and 37.5% in metachronous. T1 was detected in 71 and 66% of cases in the second tumor, synchronous and metachronous respectively, and in 28 and 25% of cases in the first tumor, always synchronous and metachronous. The 71.4% of synchronous carcinomas and the 83.3% of metachronous carcinomas were represented by invasive ductal carcinoma (IDC). Between the first and the second metachronous carcinoma the free time interval ranged from 11 to 144 months (mean, 67 months). All the patients were treated by surgery and adjuvant therapy (RT, CT, HT) according to stage, to menopausal status and to receptor status. In synchronous carcinomas only 1 recurrence was recorded, while in metachronous carcinomas the recurrences were 5. The 5-year actuarial survival was of 100% in synchronous carcinomas and of 33% in metachronous carcinomas independently of stage, while the 5-year actuarial survival after the metachronous tumor was of 50%, if the free time interval was less than 3 years, and of 75%, if more.

More on false thrombocytopenias: EDTA-dependent pseudothrombocytopenia associated with a congenital platelet release defect.

We report herein the case of a 54-year-old woman with a moderate bleeding tendency, diagnosed as an EDTA-dependent pseudothrombocytopenia associated with a congenital platelet release defect. The patient, at the age of 12, had a misleading diagnosis of idiopathic thrombocytopenic purpura and all the recurrent bleeding problems she had during her life were referred to that disease. The recent correct diagnosis of a false thrombocytopenia stimulated further laboratory investigation on the cause of the patient's bleeding tendency with the consequent identification of a congenital platelet deficiency of the arachidonic acid pathway. This finding is of relevant importance for the management of the patient in case of elective surgery or hemorrhagic emergency.

[Primary gastric lymphoma. 14 clinical cases]. / Linfoma gastrico primitivo. 14 casi clinici.

Fourteen patients affected by primary gastric lymphoma were observed retrospectively to verify the results of surgical and adjuvant chemotherapy. After a 85% preoperative diagnostic specificity, 79% of patients were subjected to surgical therapy by subtotal gastrectomy (93%) and by total gastrectomy (7%), and 64% of patients were subjected to adjuvant chemotherapy in conformity with CHOP and CVP. Classified by the Working formulation, 57% of cases presented a high grade of malignancy, 29% a low grade and 14% an intermediate grade. Classified by Ann Arbor with Mushoff's modification, 43% of patients were assigned to stage IIE1, 36% to stage IE, 14% to stage IIE2 and 7% to stage IIIE. Operative mortality was null. The overall median survival have been of 21 months, while surgical and chemotherapeutical median survival reached 32 months. The 5-year actuarial survival was: 10% (overall), 14% (treated patients), 50% (low grade), 33% (stage IE). With negative influence by istology and staging.

Identification of three tyrosine residues of glycoprotein Ib alpha with distinct roles in von Willebrand factor and alpha-thrombin binding.

The interaction between von Willebrand factor (vWF) and the platelet membrane glycoprotein (GP) Ib-IX-V complex is essential for platelet adhesion at sites of vascular injury under high shear stress flow conditions. Moreover, GP Ib-IX-V may contribute to the mechanisms of platelet activation through its high affinity binding of alpha-thrombin. There are two distinct but partially overlapping regions of GP Ib alpha thought to be involved in interacting with vWF (residues 251-279) and alpha-thrombin (residues 271-284); they share three tyrosine residues (positions 276, 278, and 279) that have recently been shown to be sulfated (Dong, J., Li, C. Q., and Lopez, J.A. (1994) Biochemistry 33, 13946-13953). To define the functional role of these three residues, we have introduced selected mutations in a soluble recombinant GP Ib alpha fragment (corresponding to the sequence 1-302 of the mature protein) that binds vWF and alpha-thrombin with the same attributes as intact GP Ib-IX-V complex. Fragments containing a single Tyr-->Phe substitution either at position 276 or 278 or 279 exhibited normal interaction with vWF but markedly reduced or absent binding of alpha-thrombin. GP Ib alpha fragment with normal sequence but synthesized under sulfate-free conditions also failed to bind alpha-thrombin and, in addition, had markedly reduced interaction with vWF. The simultaneous substitution of three neighboring Asp residues with Asn at positions 272, 274, and 277, a multiple mutation that may impair Tyr sulfation, also resulted in loss of binding of both ligands. These results define distinct structural features of GP Ib alpha selectively involved in supporting the interaction with vWF or alpha-thrombin.

[Comparison between ranitidine, famotidine, and omeprazole in the treatment of bleeding duodenal ulcer]. / Confronto tra ranitidina, famotidina e omeprazolo nel trattamento dell'ulcera duodenale sanguinante.

A trial was carried out to compare the efficacy and safety of ranitidine 300 mg die, famotidine 40 mg die and omeprazole 20 mg die in short-term treatment of bleeding duodenal ulcer in 3 groups of 15 patients. The healing rates after 2.4 weeks were 33.60% respectively with ranitidine, 40, 70% respectively with famotidine and 53, 93% respectively with omeprazole. All the drugs were well tolerated and the adverse events were infrequent and moderate. The recurrence rates after 6, 12 months were 20, 33% respectively with ranitidine, 13, 20% respectively with famotidine and only 7, 13% respectively with omeprazole. In our experience, omeprazole seems to be superior to famotidine and to ranitidine in the short-term treatment of bleeding duodenal ulcer, with the shortest relapse rate.

Biotin-avidin immobilization of platelet glycoproteins (BAIPG): a new capture assay for the detection of anti-platelet antibodies.

Several 'capture' assays are currently employed to identify specific platelet antibodies, but all require the use of murine monoclonal antibodies (MoAbs) against the antigen of interest. We have developed a new antigen capture assay for the detection of platelet reactive antibodies, based on platelet surface sialoglycoprotein labelling with biotin hydrazide, and a following immobilization of the biotinylated platelet proteins to microtiter wells that had been coated with streptavidin. The resulting solid phase can then be used in a simple ELISA to detect serum and platelet associated antibodies. We describe here two versions of this biotin-avidin immobilization of platelet glycoproteins (BAIPG) assay. In BAIPG assay type I, the test sera are directly incubated in microtiter wells previously coated with streptavidin plus biotinylated platelet proteins. The BAIPG type II procedure involves the incubation of sera with biotinylated platelets before platelet solubilization, and, after platelet lysis, the immobilization of the immune complexes to streptavidin-coated wells. In both cases, the bound antibodies are determined by alkaline phosphatase conjugated anti-human IgG. Using BAIPG type I, positive results were obtained in 7/33 patients with idiopathic thrombocytopenic purpura (ITP), 1/10 patients with secondary immune thrombocytopenia (SIT) and 4/17 with non-immune thrombocytopenia (NIT). The BAIPG type II test was positive in 13 out of 33 patients with ITP, in six out of ten patients with SIT, and in three out of the 17 patients with NIT. A comparison between BAIPG and monoclonal antibody immobilization of platelet antigens (MAIPA) assays showed a high degree of correlation between the two methods. These results suggest that the BAIPG assay is a valuable new tool for the detection of anti-platelet antibodies.