Biomedical subjects

J C Reverter

Publications and source records attributed to J C Reverter.

At least 73 records · Page 4Linked to original sources

PubMed1994

Impact of response to treatment on survival in multiple myeloma: results in a series of 243 patients.

Two hundred and forty-three patients diagnosed with multiple myeloma (MM) in a single institution over a 22-year period and treated with standard chemotherapy were analysed in an attempt to determine the impact of response to therapy on survival. The overall response rate in 229 evaluable patients was 50.1% (34.9% objective response plus 15.2% partial response). Median survivals of patients with objective and partial response were 43.4 and 42.8 months, respectively, versus 19 months for nonresponders. Median survival of 14 patients who achieved a complete remission was 42 months, whereas in 21 rapid responders (< or = 2 months) median survival was 43.3 months. A significant correlation between response and survival was observed with the landmark (P = 0.0169), the Mantel & Byar (P = 0.0001) and the Cox regression model (P < 0.0001) methods. These results indicate that, in responding patients, neither the degree of response nor the response kinetics has a significant influence on survival. However, the response to therapy is associated with a significantly longer survival in MM patients.

Adult↗

PubMed1994

Antibodies to endothelial cells in Behçet's disease: cell-binding heterogeneity and association with clinical activity.

OBJECTIVES: To investigate the prevalence and characteristics of antibodies to endothelial cells (aEC) from large vessel and from microvasculature in a group of patients with Behçet's disease (BD) to determine the relationship of these antibodies with clinical and laboratory features of the disease. METHODS: Thirty patients with BD were prospectively and consecutively studied. The aEC were determined by enzyme-linked immunosorbent assay (ELISA) using endothelial cells derived from human umbilical vein (large vessel) as well as from retroperitoneal adipose tissue (microvasculature). RESULTS: Fifteen patients (50%) had aEC, either directed to large vessel [8(26%) patients] or microvascular [13(43%) patients] endothelial cells. The percentage of active patients was significantly higher in the aEC-positive group [12(80%) patients] compared with the aEC-negative group [5(33%) patients] (p < 0.05). CONCLUSIONS: Patients with BD have a high prevalence of aEC when microvascular endothelial cells are used in the assay. These antibodies seem to be a marker of disease activity in this condition, previously considered as negative for autoantibodies.

Adipose Tissue↗

PubMed1994

Low-grade lymphoma: clinical and prognostic studies in a series of 143 patients from a single institution.

Clinical and prognostic studies were carried out in a series of 143 patients with low-grade (small-lymphocytic, follicular small cleaved cell, follicular mixed small- and large-cell) lymphoma. After treatment with alkylating agents (21.5% cases), combination chemotherapy (73.3%) or other therapies (5.2%), complete response (CR) was obtained in 40.7% of cases and partial response (PR) in 43.7%. The stage of the disease was the most important factor for response. With a median follow-up of 6.5 years, 48.0% (95% Cl: 37.5-58.5) of patients were alive 10 years after diagnosis. Among the initial parameters, advanced stage. B-symptoms, poor performance status, nodal involvement > 3 sites, extranodal involvement > or = 2 sites, WBC count > or = 10 x 10(9)/L, leukemic expression, high serum LDH levels, and bone marrow infiltration were all related to survival; treatment modality, however, had no influence on survival. In the multivariate analysis, stage (p = 0.008) and age (p = 0.053) were the most important prognostic factors. When considering response to therapy, both CR (p < 0.001) and PR (p = 0.003) emerged as the most important predictive variables, with only the absence of B-symptoms retaining its prognostic significance (p = 0.014) among the other parameters. In addition, in CR patients the duration of the response (< or = 1 year vs. > 1 year) was the most significant parameter for survival (p < 0.001). Finally, the initial stage (p = 0.011) and the histologic subtype (those patients with follicular mixed lymphoma relapsing less frequently than the others) (p = 0.052) were the only significant factors for relapse.

Adult↗

PubMed1994

Platelet activation during hemodialysis measured through exposure of p-selectin: analysis by flow cytometric and ultrastructural techniques.

P-selectin is a platelet protein in alpha-granules that is expressed on their membranes after platelet activation. Using a specific monoclonal antibody (RUU-2.17), we have studied platelet activation during hemodialysis with a cuprophan membrane in eight patients with uremia. Blood samples were obtained before hemodialysis from venipuncture (sample I), at the beginning of the hemodialysis from the arterial (sample II) and venous lines (sample III), and after 2 hours of hemodialysis from the venous line (sample IV). Exposure of P-selectin on platelet surface was studied by flow cytometry, and morphologic and immunocytochemical studies were performed. No differences in P-selectin expression were observed by single-labeling flow cytometry in samples I, II, and IV. However, a significant increase in fluorescence occurred in sample III (percentage of positive platelets [%PP], 18.0% +/- 6.1%) with respect to sample I (%PP, 6.9% +/- 2.0%; p < 0.01). An apparently decreased fluorescence was seen in sample IV (%PP, 8.8% +/- 3.9%) with respect to sample III. Double-labeling flow cytometry showed statistically significant differences between sample I (%PP, 7.1% +/- 2.6%) and sample III (%PP, 19.4% +/- 9.4%; p < 0.01) and IV (%PP, 19.0% +/- 10.1%; p < 0.01), but not between samples III and IV. The ultrastructural study revealed an increasing number of platelet morphologic signs of activation throughout the period of hemodialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Acquired aplastic anemia: a stereological analysis of bone marrow fatty tissue and its clinical correlations].

BACKGROUND: To analyze the changes of the number and size of bone marrow adipocytes in aplastic anaemia. To discover possible clinical and haematological factors which may be associated with predominant expansion of the number or size of adipocytes. To analyze the prognostic value of the adipocyte number and size. METHODS: The adipose tissue of 25 plastic-embedded bone marrow specimens corresponding to patients with aplastic anaemia was studied stereologically. The correlation study between the results obtained and clinical and haematological data was carried out. RESULTS: The expansion of the adipose tissue is due to the predominant increase of the adipocyte number in some cases and of the adipocyte size in others. Among different clinical and haematological factors, only a lower age is significantly associated with a predominant increase of adipocyte number. In the prognostic stratification performed according to three different systems, neither the adipocyte number nor the size showed a statistically significant association. CONCLUSIONS: In the aplastic anaemia, the younger patients expand their bone marrow adipose tissue by increasing predominantly the adipocyte number, whereas in the older patients this occurs by predominantly increasing the adipocyte size (may be due to the decrease in proliferative potential). On the other hand, both the adipocyte number and size lack prognostic significance.

Adipocytes↗

PubMed1993

Screening for mutations in the antithrombin III gene causing recurrent venous thrombosis by single-strand conformation polymorphism analysis.

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Antithrombin III↗

PubMed1993

Stereological study of human bone marrow adipocytes. A comparison of four methods for estimating size distributions.

Several methods are available for estimating size distributions of spherical objects in tissue sections. In this article a comparative study of four stereological techniques applied to human bone marrow adipocytes was carried out. In the first part, four stereological methods (Giger-Riedwyl, Saltykov, Wicksell, and Cruz-Orive) were used for the evaluation of adipocyte size in a set of 50 human bone marrow specimens (20 normal controls, 10 aplastic, 10 hyperplastic and 10 dysplastic bone marrows). In the second part, a computer simulation model was employed for generating both control and test populations. The latter were analyzed by means of the four stereological methods and compared to the control. When applied to bone marrow specimens, no statistically significant differences were seen among the four methods. Results were very close between the Giger-Riedwyl and Saltykov methods, and between the Wicksell and Cruz-Orive methods. In the simulation model, Saltykov's method was the most accurate stereological technique for the studied conditions. Additional advantages of this method are that the assumption of Gaussian distribution is not required, and that a higher relative weight is assigned to the largest classes, in which accurate definition is easier in the microphotographs. However, since the differences among the four methods are very small, they may all be considered as valid for the stereological study of human bone marrow adipocytes.

Adipocytes↗

PubMed1993

Prothrombin fragment 1 + 2 and thrombin-antithrombin complex measurements indicate continuous and progressive intraoperative thrombin generation in liver transplantation.

Prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin complex (TAT) have been measured in the different surgical phases in 40 patients undergoing 43 orthotopic liver transplantations (OLT), in order to study thrombin generation throughout the surgical procedure. F1 + 2 and TAT progressively rose from preoperative values (1.47 +/- 0.92 nmol/l and 22.41 +/- 19.15 ng/ml, respectively) to the end of anhepatic phase (5.97 +/- 2.20 nmol/l, 64.24 +/- 11.30 ng/ml), whereas changes in circulating antithrombin III (ATIII) were negligible in this period. Thrombin generation continued to slightly but significantly increase immediately after liver graft reperfusion (F1 + 2 6.87 +/- 1.65 nmol/l, TAT 89.32 +/- 7.54 ng/ml), and ATIII levels decreased from 70.61 +/- 12.28 to 57.16 +/- 9.57%. Higher preoperative values of F1 + 2 were associated with larger requirements of both packed red blood cells and fresh frozen plasma (FFP) in the host liver explantation phase, whereas the lowest basal levels of ATIII were related to a higher plasma expense in the whole OLT procedure. The activation of circulating prothrombin begins early in OLT, and adequate FFP infusion is capable of maintaining appropriate circulating thrombin-inhibitory activity.

Adolescent↗

PubMed1993

Large-cell lymphoma: a study of prognostic factors and assessment of five recently proposed predictive systems.

The main initial and evolutive variables of 133 patients with large-cell lymphoma treated with adriamycin-containing regimens were evaluated for prognostic significance. At the time of analysis, 66 patients had died with the median survival of the series being 48.9 months. Variables associated with poor prognosis in the univariate study were: lymphoma of immunoblastic subtype, advanced Ann Arbor stage, presence of B-symptoms, poor performance status, bulky disease (> or = 10 cm), involvement of two or more extranodal sites, bone marrow infiltration, and high serum LDH levels. In the multivariate analysis, Ann Arbor stage (p < 0.001), bulky disease (p = 0.004), performance status (p = 0.018), and histologic subtype (p = 0.021) retained their prognostic value. After excluding those patients with localized disease (stage I), the Ann Arbor staging system lost prognostic significance in favor of bone marrow infiltration (p = 0.009) and serum LDH (p < 0.001). However, when response to treatment was included in the regression model, it proved to be the most important prognostic factor (p < 0.001), followed by serum LDH (p = 0.004). On the other hand, when the analysis was restricted to complete responders, serum LDH at diagnosis was the only parameter useful to predict survival (p = 0.008). Finally, five recently proposed prognostic classifications were useful to separate different risk-groups of patients when applied to the series.

Aged↗

PubMed1993

[The adaptation of human bone marrow adipose tissue to various degrees of hematopoietic cellularity].

PURPOSE: To assess whether the variations in the number and size of the adipocytes are proportional, or not, to the changes of the fat tissue fraction (FF) associated to different degrees of hematopoietic cellularity of the bone-marrow. MATERIAL AND METHODS: The material was made up of 28 specimens of bone marrow biopsy, from which 265 microscopic fields representing a wide range of FF were obtained. As index of proportionality, the ratio N/S (adipocyte number/size) was employed. RESULTS: The parameters FF and N/S showed a highly significant correlation (r = 0.89; p = 0.00000003) at low-normal FF range (< 40%), whereas at high FF range (> 40%), such a correlation was lacking (r = 0.01; p = 0.86). CONCLUSION: At low-normal FF the adipocyte number and size vary proportionally. Conversely, at high FF, in some cases a more marked increase of number and in other instances of adipocyte size is detected. Further investigations are needed to find out the responsible factors for this different behaviour.

Adaptation, Physiological↗

PubMed1993

Platelet activation on hemodialysis: influence of dialysis membranes.

During hemodialysis, platelets are activated and release alpha-granule-specific proteins. GMP-140 is a glycoprotein stored in the alpha-granules of platelets, which is selectively expressed on the plasma membrane of activated platelets. Using a specific monoclonal antibody against this protein (CD 62), we have evaluated the influence of different dialysis membranes on hemodialysis-induced platelet activation in vivo by flow cytometry in nine patients with end-stage renal disease on maintenance hemodialysis. Five membranes were evaluated: Cuprophane, cellulose acetate, polymethylmethacrylate, polysulphone and polyacrylonitrile (AN-69). Blood samples were obtained before hemodialysis and from the inlet and outlet lines five minutes after the beginning of hemodialysis. A significant increase in the GMP-140 expression was observed in samples obtained from the outlet line compared with samples obtained from the inlet line for all membranes evaluated, but the extent of this increase depended on the type of membrane used: Cuprophane 13.95 +/- 3.94%, cellulose acetate 7.4 +/- 4.52%, polymethylmethacrylate 6.93 +/- 4.6%, polysulphone 3.83 +/- 2%, and AN-69 2.14 +/- 2.19% (mean +/- SD). Cuprophane induced the highest degree of platelet activation (P < 0.05). Cellulose acetate and polymethylmethacrylate induced more platelet activation than polysulphone or AN-69 (P < 0.05). These data demonstrate that all hemodialysis membranes induce platelet activation but to a variable extent, cuprophane being the most activating membrane, cellulose acetate and polymethylmethacrylate showing an intermediate potential of activation, while the more biocompatible membranes, polysulphone and AN-69, inducing the lowest degree of platelet activation.

Adult↗

PubMed1993

[Adaptation of human bone marrow adipose tissue to different grades of hemopoietic cellularity].

Adipose Tissue↗

PubMed1992

Multicentric evaluation of a new assay for prothrombin fragment F1+2 determination.

A multicenter study of a recently developed ELISA for the determination of prothrombin fragment F1+2 was performed in order to evaluate analytical and clinical aspects. Mean intra-assay and inter-assay reproducibility were found to be 11.0 and 12.6%, respectively. The measuring range covered by the calibration curve reaches from 0.04 to 10.0 nM/l F1+2. Testing 133 healthy subjects a reference range of 0.37 to 1.11 nM/l F1+2 (2.5-97.5 percentile) with a median of 0.66 nM/l F1+2 was calculated. Minor difficulties with blood sampling (venous occlusion for 2 min) did not affect F1+2 plasma concentrations. Significantly increased F1+2 levels were measured in patients with leukemia (p < 0.0001), severe liver disease (p < 0.005) and after myocardial infarction (p < 0.01). Elevated F1+2 concentration before the beginning of heparin therapy (1.25 nM/l) decreased to 0.77 nM/l (p < 0.0001) after 1 day of therapy. For patients in the stable phase of oral anticoagulant therapy decreasing F1+2 concentrations were measured with increasing INR. F1+2 levels were already significantly reduced in patients with INR < 2.0 (0.56 nM/l; p = 0.0005). Thus F1+2 determination may be helpful in identifying activation processes as well as in monitoring anticoagulant therapy.

Administration, Oral↗

PubMed1992

Recombinant human erythropoietin treatment improves platelet function in uremic patients.

The effect of recombinant human erythropoietin (rHuEPO) on primary hemostasis was tested in 19 hemodialyzed patients. Bleeding time, platelet aggregation and platelet interaction with vessel subendothelium (SE) under flow conditions were determined before treatment and after patients reached hematocrits greater than or equal to 30%. Two thrombotic events (an acute myocardial infarction and an AV fistula clotting) were recorded during the early stages of treatment. A shortening of average bleeding times (P less than 0.01), an increase in platelet count (P less than 0.01) and an improvement of platelet aggregation (P less than 0.01) and of platelet-SE interaction (P less than 0.01) were observed. A low correlation index was found between hematocrit and bleeding time (r = -0.351, P less than 0.05). To assess a possible effect of rHuEPO on platelet function, the same parameters were evaluated before and after receiving three doses of rHuEPO (40 U/kg i.v. post-hemodialysis) in 14 of the patients. No changes in platelet or erythrocyte counts were observed, the mean bleeding time remained unchanged, but platelet aggregation induced by arachidonic acid (P less than 0.05), ADP (P less than 0.01) and ristocetin (P less than 0.05) improved. Perfusion studies confirmed moderate but significant increases in the parameters that quantify platelet-SE interaction (P less than 0.05). Improvement of ADP-induced aggregation correlated with the increase of platelet adhesion to SE (r = 0.675, P less than 0.05). We conclude that rHuEPO treatment improves primary hemostasis in uremia through an increase of red cell mass but also through a beneficial effect on platelet function, which is independent of the hematocrit rise.

Adult↗

PubMed1992

A variant of Glanzmann's thrombasthenia which fails to express a GPIIb-IIIa related epitope that is recognized by a specific monoclonal antibody (C17).

Binding of different antibodies to the GPIIb-IIIa complex in resting (AP2, EDU3, C17) or activated platelets (PAC1) was studied by flow cytometry in a patient with a platelet defect involving GPIIb-IIIa related functions. The patient has a mild history of bleeding. Aggregation induced by ADP and collagen were absent but normal response was obtained with ristocetin. Platelets from the patient do not bind fibrinogen. Perfusion studies with flowing blood showed that patient's platelets have a marked impairment in the process of spreading and aggregate formation on vascular subendothelium. Electrophoretic studies in SDS-polyacrylamide gels demonstrated the presence of normal amounts and normal mobility of GPIIb-IIIa. Fibrinogen was present in the patient's platelets (68-74% of controls). The binding of AP2 and EDU3 to patient's resting platelets was normal as assessed by flow cytometry. In contrast, a decreased presence of the C17 antigen (10 fold lower than control platelets) was detected in resting platelets and a markedly reduced binding of PAC1 was found in thrombin activated platelets. These studies suggest that C17 recognizes an epitope of the GPIIb-IIIa in resting platelets that is implicated in the regulation of adhesive and cohesive properties of GPIIb-IIIa. Studies on this patient might be helpful for the understanding of GPIIb-IIIa functions.

Adenosine Diphosphate↗

PubMed1992

The value of detecting surface and cytoplasmic antigens in acute myeloid leukaemia.

The immunophenotype of leukaemia cells from 60 patients with acute myeloid leukaemia (AML) was analysed with the APAAP technique using a panel of anti-myeloid and lymphoid associated monoclonal antibodies (McAb). Cells from all cases, including three with negative cytochemical features, were labelled by at least one of the anti-myeloid McAb CD13, anti-myeloperoxidase (anti-Mpo), and/or CD14. The most sensitive marker was CD13, since it was positive in 90% of cases. In two out of three AML cases defined as M0-AML, CD13 was expressed in the cytoplasm but not on the membrane; in these three cases peroxidase (Mpo) was not detected by conventional cytochemistry, but could be demonstrated in all of them using the McAb anti-Mpo. The simultaneous expression of CD14 and CD68 McAb was often confined to the M4 and M5 FAB AML subtypes (92% cases) as compared to the others: M1, M2, M3 (18% cases). Lymphoid antigens were rarely positive (TdT+: 13%, CD7+: 15%, CD19+: 5%) and none of the AML cases were CD3+ or CD10+. By contrast, CD4 was expressed in blasts from 44% of cases and this was not restricted to AML with a monocytic component (M4, M5) but also found in other subtypes. There were no significant differences in the clinical or prognostic features according to the positivity or negativity with TdT and CD4. By contrast, expression of CD7 was associated with refractoriness to the treatment or short complete remission duration, although the number of patients is too small to draw firm conclusions. Our findings support the clinical and diagnostic relevance of immunophenotypic studies in AML.

Acute Disease↗

PubMed1992

Hemostatic effect of platelet von Willebrand factor.

In type III von Willebrand disease (vWD) patients, the bleeding time was only partially corrected or not modified after cryoprecipitate infusion, although the levels and the multimeric structure of plasma von Willebrand factor (vWF) were normal. However, the adhesion of normal platelets on the vessel wall subendothelium in the presence of postinfusion patient plasma improved more significantly than the bleeding time. These results suggest a role of the vWF released from normal platelets which is absent in type III vWD platelets. In 5 patients transfusion of normal platelet concentrates performed 1 h after cryoprecipitate infusion without modification of the bleeding time (> 30 min) normalized this parameter, and platelet adhesion to the subendothelium elicited a marked improvement. These last results confirm the suggestion that platelet vWF plays an important 'in vivo' role in the hemostatic process, particularly in patients suffering from severe vWD.

Animals↗

PubMed1992

Plasma from systemic lupus erythematosus patients with antiphospholipid antibodies promotes platelet aggregation. Studies in a perfusion system.

The possible platelet-aggregating effect of plasma from systemic lupus erythematosus (SLE) patients (n = 19) was investigated under flow conditions. Aliquots of the SLE plasmas with (n = 10) or without (n = 9) anticardiolipin antibodies (ACAs) were added to anticoagulated blood (1:20, vol/vol). Plasma from normal donors was used as a control. Blood was incubated for 15 minutes at 37 degrees C and then perfused through annular chambers containing denuded arterial segments. Perfusions were performed for 10 minutes at a shear rate of 800 sec-1. The interaction of platelets with vessel subendothelium (SE) was morphometrically evaluated in thin sections. In control experiments, the percentage of the SE covered with platelets was 23.6 +/- 4.3% (mean +/- SD). Large aggregates (more than 5 microns in height) covering 11.8 +/- 5.7% of the exposed SE were noted. The deposition of platelets was statistically increased (38.5 +/- 7.6%, p less than 0.01 versus control) in the presence of SLE plasmas with demonstrated antiphospholipid antibodies (APAs). The formation of large aggregates was also augmented (30.3 +/- 5.9%, p less than 0.01 versus control). A similar response was obtained after addition of affinity-purified immunoglobulin G and immunoglobulin M fractions from two patients with ACAs. SLE plasmas with no detectable APAs did not influence the morphometric parameters studied. Results of the present study indicate that the presence of APAs in SLE plasma promotes platelet aggregation under flow conditions. These observations may help to explain the pathophysiology of the thrombotic events occurring in patients with APAs.

Adolescent↗