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Biomedical subjects

R Castillo

Publications and source records attributed to R Castillo.

At least 73 records · Page 4Linked to original sources
PubMed1992

Visceral leishmaniasis in HIV-1-infected individuals: a common opportunistic infection in Spain?

OBJECTIVE: To investigate the epidemiological, clinical and biological features of visceral leishmaniasis (VL) in patients with HIV-1 infection. DESIGN: Retrospective study. SETTING: Three university hospitals in southern Spain. PATIENTS: Forty-seven adult patients with VL and HIV-1 infection diagnosed between January 1986 and November 1991. RESULTS: Forty-five out of the 47 (96%) cases were diagnosed in the last 2 years. Fever (87%), hepatomegaly (74%), splenomegaly (72%) and pancytopenia (77%) were the most common presenting features. Most patients (79%) were strongly immunocompromised when VL was diagnosed, and were in stage IV of the Centers for Disease Control classification; 87% had a CD4 lymphocyte count < 200 x 10(6)/l. However, VL was the first severe infection diagnosed in 10 cases. Significant titres (> 1:40) of antileishmanial antibodies were detected by indirect immunofluorescence in five out of 16 (31%) cases only. Clinical response to the therapy was difficult to assess. Microbiological response was achieved in only 38% of the patients evaluated. CONCLUSIONS: Leishmaniasis is a relatively common infection in HIV-1-infected individuals in southern Spain. Its clinical picture is quite uniform and it can be the first opportunistic infection in individuals with HIV-1. In endemic areas, a high index of clinical suspicion should be maintained in order to avoid underdiagnosis of leishmaniasis.

AIDS-Related Opportunistic Infections↗
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

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↗
PubMed1992

Contribution of perfusion techniques to the evaluation of the hemostatic effectiveness of platelet concentrates.

Perfusion systems allowing the morphometric analysis of platelet interactions with vessel subendothelium under flow conditions have been applied to evaluate the quality and function of stored platelets. Studies performed in vitro indicate that despite the existence of storage lesions, platelets in concentrates stored for up to 5 days retain their ability to interact with the subendothelium. Perfusion studies ex vivo with nonanticoagulated blood from anemic-thrombocytopenic patients have shown the critical hemorrheological role of red blood cells facilitating platelet interactions with subendothelium. Similar studies performed on severely thrombocytopenic patients who received transfusions of platelets stored at 4 degrees C indicate that incompletely viable platelets can contribute to primary hemostasis through procoagulant mechanisms. The latter results suggest that storage lesions which contribute to impairment of platelet function may result in enhancement of platelet procoagulant activities. Perfusion techniques have contributed to the evaluation of the hemostatic effectiveness of platelet concentrates. These techniques will provide a useful model to test the impact of new storage technologies on platelet hemostatic function.

Animals↗
PubMed1992

The role of subendothelial laminin and platelet laminin receptors in haemostasis.

Laminin (LM) is a basement membrane glyco-protein which exhibits a number of biological activities, including the promotion of cell attachment and migration. In a static system, platelets attach to LM without spreading. In order to elucidate the mechanisms mediating platelet-LM interactions under flow conditions, we studied the effects of blocking subendothelial LM and its platelet receptor. We measured the extent of platelet adhesion to the endothelial cell extracellular matrix (ECM) using a parallel plate perfusion chamber. To do this, we performed the following experiments: i) blockade of subendothelial LM by incubation of ECM with an anti-LM antibody (Ab); ii) blockade of the platelet receptor for LM with: a) an anti-67 KDa receptor Ab; and b) three different LM-derived peptides (CFALRGDNP, IKVAV and CDPGYIGSR). In i) perfusates consisted of whole blood, whereas in ii) perfusates were prepared with washed platelets pre-incubated with Ab or peptides and reconstituted with plasma and washed red blood cells. Perfusions were carried out at 800 s-1 shear rate. Platelet deposition was morphometrically evaluated by a computerized system. Our results indicated that when ECM was pre-incubated with an anti-LM Ab (100 micrograms/ml, 30 min, 37 degrees C) a reduction of the surface coverage (SC) of 23.3 +/- 2.3% (p less than 0.01) was observed. When washed platelets were pre-incubated with an anti-67 KDa receptor Ab (40 micrograms/ml, 30 min, 37 degrees C) their interaction with ECM was decreased by 22.3 +/- 2.1% of SC (p less than 0.005). In other experiments platelets were pre-incubated with CFALRGDNP, IKVAV and CDPGYIGSR (200 micrograms/ml, 30 min, 37 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Squid hypersensitivity: a clinical and immunologic study.

Hypersensitivity to mollusk has rarely been described in the literature. Among the mollusks, the cephalopods are a group of great importance as a food source. We report seven patients who had had symptoms highly suggestive of IgE-mediated reactions after ingesting squid or inhaling vapors from cooking squid. All had previously suffered from persistent rhinitis or asthma for years. In addition, six of the seven patients had had symptoms after ingesting shrimp. Skin prick tests were strongly positive for boiled squid extract and for various commercial crustacean extracts. Specific IgE antibodies against boiled extract and several crustacean extracts were demonstrated in all patients by RAST and reverse enzyme immunoassay. Cross reactivity between squid and shrimp and other crustaceans was demonstrated by reverse immunoassay inhibition studies. Cross reactivity could not be demonstrated between squid and octopus, which are both cephalopods, nor between squid and other mollusks.

Adult↗
PubMed1991

Dipyridamole induces changes in the thrombogenic properties of extracellular matrix generated by endothelial cells in culture.

Dipyridamole (DIP) is a drug widely used as an antiplatelet agent, which also has effects on endothelial cells. In this study, the effects of treating confluent endothelial cell monolayers (EC) with DIP on EC viability (trypan blue exclusion test) and metabolic activity (3H-thymidine incorporation) were examined. Platelet reactivity of the extracellular matrix (ECM) produced by untreated and DIP-treated ECs was determined morphometrically by a perfusion technique. Levels of ECM-associated von Willebrand factor (vWF) and fibronectin (FN) were also quantified (ELISA). The present results indicate that treatment of EC with 10 microM DIP did not reduce EC viability but that the incorporation of labelled nucleotides was significantly decreased (p less than 0.01). Platelet deposition onto the ECM generated by DIP-treated cells, perfused at a shear rate of 1300 sec-1, differed significantly with respect to controls (p less than 0.05), and platelet adhesion was also reduced (25% less, p less than 0.05). This effect was shear rate dependent, as no differences were noted when the ECMs were perfused at 300 sec-1 shear rate. Levels of VWF and FN associated with ECM remained unchanged with respect to controls. These results suggest that treatment with DIP alters EC metabolic activity, which in turn, influences the reactivity of the ECM generated by treated cells.

Cell Count↗
PubMed1991

Thrombin generation and fibrinolysis in the thrombotic thrombocytopenic purpura and the hemolytic-uremic syndrome.

Prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin complexes (TAT), as well as other coagulation and fibrinolysis parameters, were studied in a series of 13 patients affected by thrombotic thrombocytopenic purpura (TTP) or hemolytic-uremic syndrome (HUS). Fragment F1 + 2 was found to be increased in all patients at diagnosis (patients' range, 1.21-19.03 nmol/l; normal limits, 0.28-1.08 nmol/l), and remained also higher than normal after treatment with plasma exchange (patients' range, 1.5-4.01 nmol/l). Even though the analysis of fibrinolysis markers did not show a definite state of hypo or hyperfibrinolysis in the systemic circulation, enhanced circulating D-dimer levels (0.53-12.6 micrograms/ml, normal levels of 0.03-0.29 micrograms/ml) indicated that a certain grade of fibrin lysis was present at previously formed thrombi. Plasma PAI-1 activities either on admission (9.2-38.2 U/ml) and after plasma exchange therapy (2.6-38.6 U/ml) showed a behavior irrespective of t-PA:Ag changes, and post-plasmapheresis values remained high only in patients with fatal neurological outcome. Nevertheless, no correlations between clinical and laboratory data could be established useful for the TTP/HUS prognosis. We conclude that increased thrombin generation occurring in damaged areas is appropriately inhibited by antithrombin III in the systemic circulation, avoiding consumption coagulopathy to develop in uncomplicated patients. In addition, fibrinolysis data suggest that elevated PAI-1 may decisively favor the development of microvascular thrombi.

Antithrombin III↗
PubMed1991

Incidence of non-A, non-B hepatitis after screening blood donors for antibodies to hepatitis C virus and surrogate markers.

OBJECTIVE: To compare the effect of screening blood donors for antibodies to hepatitis C virus (anti-HCV) on the incidence of non-A, non-B hepatitis in recipients with that of screening blood donors for antibodies to hepatitis B core antigen (anti-HBc) and elevated alanine aminotransferase levels. DESIGN: Cohort analysis of serum samples from donors and recipients. Recipients were followed for 12 months to determine the occurrence of non-A, non-B hepatitis. SETTING: The blood-transmitted viruses unit and the liver unit of a university teaching hospital. SUBJECTS: A total of 250 patients who had open heart surgery and their 3142 blood donors. MEASUREMENTS: Donor sera were tested for anti-HCV by enzyme-linked immunosorbent assay (ELISA) and, in the event of a positive result, by recombinant immunoblot assay (RIBA). Antibodies to anti-HBc and serum alanine aminotransferase (ALT) levels were also measured. Measurements of anti-HCV and ALT activity in recipients were done before transfusion and at regular intervals during follow-up. MAIN RESULTS: Of the 250 transfusion recipients, 40 developed non-A, non-B hepatitis. Of the 3142 donors, 70 were positive for anti-HCV by ELISA, 440 were positive for anti-HBc, and 177 had alanine aminotransferase levels between 0.67 and 1.33 mukat/L. The sensitivity (87%), specificity (89%), positive predictive value (59%), and negative predictive value (97%) of blood-donor screening were higher for anti-HCV than for anti-HBc (82%, 36%, 21%, and 91%, respectively) and 70%, 29%, and 91%, respectively). The expected number of donors excluded because of the presence of anti-HCV was considerably smaller than that of donors with positive results for surrogate markers of hepatitis. CONCLUSION: Screening blood donors for the presence of anti-HCV is more accurate than screening for surrogate markers (anti-HBc and ALT) and protects more effectively against post-transfusion non-A, non-B hepatitis.

Alanine Transaminase↗
PubMed1991

Hemostatic effect of normal platelet transfusion in severe von Willebrand disease patients.

Platelet von Willebrand factor (vWF) has been suggested to play an important role in the hemostatic process. Clinical and experimental data indicate that bleeding time (BT) and platelet-vessel wall interaction cannot be normalized unless the defect of platelet vWF is also corrected. We have examined the effect of normal platelet concentrate transfusion 1 hour after cryoprecipitate infusion in five type III von Willebrand disease (vWD) patients. The cryoprecipitate infusion attained normal circulating levels of ristocetin cofactor, vWF antigen, and factor VIII activity. In two patients, cryoprecipitate infusion did not modify the BT (greater than 30 minutes), whereas in the remaining three patients BT was only partially corrected (from greater than 30 to 12, 18, and 21 minutes). However, the immediate platelet transfusion completely corrected the BT in four cases, and in one case it shortened the BT to 8.30 minutes (n = 3 to 8 minutes). In the perfusion study, cryoprecipitate infusion only resulted in a slight increase in platelet deposition (surface coverage range: 2.4% to 11.3%), whereas the platelet concentrate transfusion elicited a more marked improvement (range: 8.2% to 26.4%; P less than .02 v post-cryoprecipitate). These results suggest an important in vivo role of the platelet vWF in supporting platelet-vessel wall interaction. They also give support to the occasional addition of normal platelet transfusion to the cryoprecipitate infusion for the control of serious bleeding episodes resistant to cryoprecipitate in severe vWD patients.

Bleeding Time↗
PubMed1991

Immune hemolytic anemia and renal failure associated with rifampicin-dependent antibodies with anti-I specificity.

A 50-year-old woman with primary biliary cirrhosis developed immune hemolytic anemia and renal failure while receiving rifampicin for the treatment of refractory pruritus. Serological studies revealed the presence of rifampicin-dependent antibodies of the IgM class that, when tested against a wide panel of erythrocytes, had anti-I specificity. Subsequently, rifampicin was withdrawn and prednisone treatment instituted, this resulting in a rapid resolution of the hemolysis, whereas hemodialysis was required for recovery of the renal function. A role is suggested for the anti-I specificity of the antibodies in the development of renal failure associated with rifampicin therapy.

Anemia, Hemolytic↗
PubMed1991

Evaluation of the transfusion effectiveness of various platelet concentrates by means of an in vitro perfusion technique.

An in vitro perfusion technique was used for the assessment of the effectiveness of platelet concentrates (PCs) administered to patients with bone marrow failure. Denuded rabbit arterial segments mounted in annular chambers were exposed to nonanticoagulated blood drawn directly from the antecubital vein. This perfusion system allows the direct visualization of platelet-subendothelium interactions. The deposition of platelets on exposed subendothelium and the presence of fibrin were evaluated morphometrically. Perfusions were performed before and 10 and 120 minutes after the transfusion of PCs that had been obtained by apheresis and administered immediately after collection (A) or separated by centrifugation of blood units and transfused 24 hours after storage at 22 degrees C (B) or 4 degrees C (C). Bleeding times were also determined systematically. The deposition of platelets on the subendothelium increased significantly (p less than 0.01) 10 minutes after transfusions of A and B PCs, but the presence of fibrin did not differ from pretransfusion values. Two hours after the administration of A or B PCs, the improvement of platelet deposition persisted. By then, the presence of fibrin increased markedly (p less than 0.01). The deposition of platelets was not modified after the transfusion of C PCs, but the presence of fibrin was augmented significantly at both posttransfusion times. Comparisons between bleeding times and morphometric results pointed to a possible role of fibrin formation in contributing to primary hemostasis.

Bleeding Time↗
PubMed1991

Methotrexate disposition following disruption of the blood-brain barrier.

Intracarotid drug administration after osmotic blood-brain barrier disruption (BBBD) enhances drug delivery to brain tumors. Despite clinical use, the pharmacokinetics of drugs following BBBD has not been described to date. Since methotrexate exhibits a concentration-toxicity response relationship, methotrexate disposition was determined following BBBD and intracarotid administration in seven patients with nonoperable brain tumors. Following a 1.5-5 g intracarotid methotrexate injection, 12 blood samples and 9 urine collections were obtained. Methotrexate concentrations in serum and urine were determined by fluorescence polarization immunoassay. The serum concentration-time data were best described by a three-compartment model. Systemic and renal clearances were consistent with previous studies. However, a prolonged mean terminal half-life of 51.5 h was observed. Serum methotrexate concentrations at 72 h exceeded 0.1 mumol/L in five of seven patients. Stomatitis occurred in one patient. Relative to previous reports, prolonged methotrexate half-life and cytotoxic methotrexate concentrations were observed in the serum of patients receiving intracarotid methotrexate following BBBD. Due to the prolonged cytotoxic methotrexate concentrations observed, extended leucovorin therapy may be indicated following BBBD and intracarotid methotrexate.

Adult↗