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Biomedical subjects

R Castillo

Publications and source records attributed to R Castillo.

At least 109 records · Page 6Linked to original sources
PubMed1990

[Effects of the treatment with human recombinant erythropoietin on primary hemostasis in uremic patients].

The effect of human recombinant erythropoietin (r-EPO) on primary hemostasia was studied in 9 patients undergoing hemodialysis. The analysis was performed before and after the hematocrit reached a value of 30%. The most important complications observed during the study period were a death for acute myocardial infarction in a patient with previous severe ischemic cardiopathy and a thrombosis of the venous line. The bleeding time shortened in four patients although the mean value did not change significantly. Platelet count showed a non significant increase. There was a significant improvement in in vitro platelet aggregability with ADP (p less than 0.05), arachidonic acid (p less than 0.05), adrenaline (p less than 0.05), and ristocetin (p less than 0.05) as well as in the parameters that quantify the interaction between platelets and subendothelium in in vitro experiments using perfused models (p less than 0.05). There were no significant changes in coagulation and fibrinolysis tests. The treatment with r-EPO improved primary hemostasia in uremic patients. This beneficial effect was due to the increased hematocrit and to the improvement of platelet function induced by r-EPO.

Adult↗
PubMed1990

Uremic platelets have a functional defect affecting the interaction of von Willebrand factor with glycoprotein IIb-IIIa.

Uremic patients have an impaired platelet function that has been related to membrane glycoprotein (GP) abnormalities. Using a perfusion system, we have studied the interaction of normal and uremic platelets with vessel subendothelium (SE) under flow conditions. Reconstituted blood containing washed platelets, purified von Willebrand factor (vWF) (1 U/mL), and normal washed red blood cells was exposed to de-endothelialized rabbit segments for 10 minutes at two different shear rates (800 and 1,600 seconds-1). In some experiments a monoclonal antibody to the GPIIb-IIIa complex (EDU3) was added to the perfusates. With normal platelets, the percentage of the vessel covered by platelets (%CS) was 23.1% +/- 3.7% at 800 seconds-1 and 30% +/- 4.3% at 1,600 seconds-1. Platelets were observed in contact or forming monolayers on vessel SE. EDU3 inhibited the spreading of normal platelets. The %CS (11.1% +/- 3.3%) was statistically decreased (P less than .01) and most of the platelets were observed in contact with the vessel surface. These data indicate that, under flow conditions, the interaction of vWF with GPIIb-IIIa can support the spreading of normal platelets in the absence of exogenous fibrinogen. Under the same experimental conditions, the interaction of uremic platelets with SE was markedly impaired at both shear rates studied (P less than .01 v normal platelets). The presence of EDU3 did not modify the interaction of uremic platelets. These results confirm the impairment of the platelet adhesion observed in uremic patients. Furthermore, they indicate the presence of a functional defect in the interaction of vWF with GPIIb-IIIa. The fact that perfusions with normal and uremic platelets in the presence of an antibody to the GPIIb-IIIa complex did not show any differences gives indirect evidence on a functionally normal interaction vWF/GPIb in uremic patients.

Blood Platelets↗
PubMed1990

[Microangiopathic thrombotic syndromes in adults: results of treatment with intensive plasmapheresis].

The response to intensive plasmapheresis was evaluated in 13 patients (7 males, 6 females; median age 28 years) with microangiopathic thrombotic syndromes (MTS) who were treated at our center during the last 10 years. The most common initial clinical features were anemia, hemorrhage and neurologic abnormalities. Twelve patients had severe thrombocytopenia and 8 had renal failure. Fourteen plasmapheresis courses were carried out to treat 13 initial episodes and one relapse. The mean volumes of removed plasma and fresh frozen plasma infused at each exchange were 57 ml/kg and 41.7 ml/kg, respectively. Eight patients received antiplatelet drugs and/or corticosteroids. After a mean number of 10.6 exchanges per patient and course, complete remission (CR) was achieved in 7 cases (6 initial episodes and one relapse) and a partial response in 3. Four patients did not respond to therapy and died from progression of the disease. The early institution of plasmapheresis and the rapidity to respond were the only factors significantly associated with the achievement of CR.

Adolescent↗
PubMed1990

Investigation of plasma von Willebrand factor and circulating platelet aggregating activity in mitomycin C-related hemolytic-uremic syndrome.

We have studied the ability of the plasma to induce aggregation of both homologous and heterologous platelets in four patients with hemolytic-uremic syndrome (HUS) associated with chemotherapy with mitomycin C (MMC). Neither platelet aggregation was elicited by patients' plasmas nor the in vitro addition of purified von Willebrand factor (vWF) had any effect on the aggregation pattern. In addition, ristocetin-induced binding of patients' vWF to formaldehyde-fixed platelets was normal, and multimeric vWF analysis revealed a normal structure of patients' plasmatic vWF whatever the clinical stage in which it was studied. These findings suggest that, in spite of the existence of common clinical and biological features in the various forms of HUS, the pathogenesis of MMC-related HUS may be, at least in part, different from that of the other forms of HUS in which both platelet-aggregating activity and alterations in the vWF are found.

Blood Platelets↗
PubMed1990

Hepatitis C virus antibodies in chronic alcoholic patients: association with severity of liver injury.

The prevalence of hepatitis C virus antibody and its relationship to the severity of liver disease in chronic alcoholic patients has been assessed, using a recently developed enzyme immunoassay and confirmed by a recombinant immunoblot assay, in 144 patients (mean age +/- S.D. = 44.4 +/- 11.3 yr) who had consumed greater than 80 gm/day ethanol for greater than 5 yr. Hepatic disease was evaluated by clinical and biochemical studies and by liver biopsy when appropriate. In addition, 76 liver biopsy specimens from these patients were analyzed to determine whether liver lesions were similar in alcoholic patients with and without hepatitis C virus antibodies. According to clinical and histological features alcoholic patients were divided into five groups: normal liver (45 patients), fibrosteatosis (20 patients), alcoholic hepatitis (14 patients), cirrhosis (61 patients) and chronic hepatitis (4 patients). Hepatitis C virus antibodies were present in 35 alcoholic patients (24.3%). The prevalence of hepatitis C virus antibodies correlated with the severity of liver injury: 2.2% in patients without liver disease, 20% in those with fibrosteatosis, 41.4% in those with alcoholic hepatitis and 42.6% in those with cirrhosis. Hepatitis C virus antibodies were found in one of the four patients with chronic hepatitis (p less than 0.001). Furthermore, patients positive for hepatitis C virus antibodies with normal liver or fibrosteatosis showed higher serum bilirubin and gamma-globulin concentrations and lower aminopyrine breath test scores than did patients negative for hepatitis C virus antibodies with normal liver or fibrosteatosis. Similar differences between patients with and without hepatitis C virus antibodies were observed in patients with alcoholic hepatitis or cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Differential localization of von Willebrand factor, fibronectin and 13-HODE in human endothelial cell cultures.

Von Willebrand factor (vWF), fibronectin (FN) and 13-hydroxy-octadecadienoic acid (13-HODE) are known to influence the regulation of the adhesive properties of vascular surfaces. In the present study vWF, FN and 13-HODE were comparatively localized in endothelial cells (EC) and in the extracellular matrix (ECM) produced by EC. An indirect immunofluorescent technique was applied to coverslips containing human EC cultures previously fixed and permeabilized following different procedures: A. Alcohol/acetone; B. Paraformaldehyde alone and C. Paraformaldehyde followed by Triton X-100. vWF was observed inside EC (A), on the ECM produced by EC (B) or in EC and ECM (C) depending on the fixation procedures used. FN was mainly localized in the ECM despite the fixation procedures employed. FN was only seen in relation to cell bodies after strong permeabilization (A). Under our experimental conditions 13-HODE was never found in ECM. This latter antigen was observed randomly dispersed in those preparations fixed with alcohol/acetone, indicating that it is probably extracted by this fixative. 13-HODE was detected in granular shaped structures in EC after permeabilization with detergent (C). These results suggest that the cellular localization of vWF and FN is compatible with an adhesive role related to the abluminal side of ECs. 13-HODE was readily observed after mild permeabilization. This finding would be morphologically consistent with its contribution to the regulation of the vessel wall thromboresistance.

Cells, Cultured↗
PubMed1990

Alfentanil potentiates midazolam-induced unconsciousness in subanalgesic doses.

The effects of alfentanil on the midazolam dose-response curve for hypnosis was studied with response to the verbal command as an end point in 95 patients. The analgesic effect of alfentanil was studied by measuring the threshold for pain caused by pressure on the trapezius muscle with the use of a dolorimeter in 21 patients. The study was randomized, double-blind, and performed on the unpremedicated patients with ASA physical status I or II. Alfentanil was found to reduce the midazolam ED50 value for the induction of anesthesia in a dose-dependent fashion. The smallest dose of alfentanil (3 micrograms/kg) that caused a marked shift of the midazolam dose-response curve to the left along the dose axis (from the ED50 of 270 micrograms/kg to the ED50 of 142 micrograms/kg, P less than 0.0005) represents approximately 2% of the alfentanil ED50 for induction of unconsciousness (130 micrograms/kg). Alfentanil (10 micrograms/kg) caused only a tendency for increase in the pain threshold, whereas a dose of 15 micrograms/kg significantly increased the pain threshold by 37% (P less than 0.05). The results demonstrate that alfentanil potentiates the hypnotic effect of midazolam in very small doses. The high potency of alfentanil in this respect, as compared to its analgesic potency, suggests a very specific mechanism of alfentanil-midazolam hypnotic interaction, one that most likely is based on a functional relationship between the GABA receptor-benzodiazepine receptor system and the opioid receptor system in mediation of hypnosis.

Adult↗
PubMed1990

[Update on the role of vascular, plasmatic and cellular components in the regulation of the interaction of platelets with the subendothelium].

The interaction of platelets (Plts) with subendothelium (SE) or with extracellular matrices (ECM) generated by endothelial cells was studied under flow conditions. The role of: a) platelet membrane glycoproteins (GPS) or subunits; b) plasma adhesive proteins such as von Willebrand factor (VWF) and fibronectin (Fn); and c) structural proteins of the SE such as laminin (Lm). Specific antibodies or purified proteins were added to the perfusates. GPS. Monoclonal antibodies (MoAb) directed against distinct epitopes of the GPIIb-IIIa affected in different manner the deposition of platelets. MoAb EDU3 decreased (p less than 0.01) the surface of the vessel covered by platelets (% CS) and increased the presence of platelets in contact (% C) with the SE. MoAb C17 did not modify the % CS but altered the morphological characteristics of the aggregates. A monoclonal antibody against GPIIb, decreased the % CS (p less than 0.01) without influencing % C; VWF. A linear progression of the % CS was observed for VWF levels ranging from 0.1 to 0.6 U/mL. A plateau was reached for concentrations of vWF above 0.6 U/mL; Fn. Perfusions in which blood was reconstituted with Fn-depleted plasma showed the cooperation of this protein facilitating Plt-Plt interaction. No statistical differences were observed in the % CS when ECM were incubated with a MoAb against Fn (3E3); Lm. The % CS decreased statistically (p less than 0.01) when SE or ECM were incubated with an antibody to Lm. These results show the critical role of vascular, plasmatic and cellular components in the maintenance of and adequate platelet function.

Animals↗
PubMed1989

Role for platelet von Willebrand factor in supporting platelet-vessel wall interactions in von Willebrand disease.

Twelve infusions of plasma concentrates of von Willebrand factor (vWF) were given to four patients with severe (type III) von Willebrand disease (vWD). Their prolonged bleeding times were either completely or partially corrected after five infusions and had not changed after the remaining seven. In contrast, the low platelet coverage of the subendothelial surface of rabbit aorta perfused with normal washed platelets and red cells resuspended in preinfusion patient plasma was completely or partially corrected in ten instances by replacing preinfusion plasma with postinfusion plasma and remained unchanged in two. Postinfusion improvement in surface coverage was greater than that in bleeding time, suggesting that vWF from normal platelets is needed to support optimal platelet-vessel wall interactions in vWD. This possibility was further explored through other perfusion experiments. The subendothelial surface covered by platelets from an untreated patient with type III vWD (containing no measurable vWF) or from a type IIA vWD patient (containing dysfunctional vWF) resuspended in normal plasma was much smaller than that covered by normal platelets resuspended in normal plasma. These results establish that platelet vWF is important in supporting platelet-vessel wall interactions in vWD and also provide experimental support in favour of the therapeutic transfusion of normal platelets in addition to vWF concentrates to correct the bleeding time in vWD patients.

Blood Platelets↗
PubMed1989

Development and initial validation of a dual-language English-Spanish format for the Arthritis Impact Measurement Scales.

Language, cultural, and educational barriers complicate efforts to validate health status questionnaires that have been translated into Spanish. To overcome these problems, a prototype dual-language format was developed for the Arthritis Impact Measurement Scales. Validity testing with 72 patients diagnosed as having rheumatoid arthritis indicated high levels of test-retest reliability, item-to-scale internal consistency, and construct validity for both Anglo and Hispanic subjects. A technique for developing and pilot-testing a questionnaire written in a regional Spanish dialect is described. Linguistic considerations, questionnaire design, and other applications are discussed in light of the results obtained.

Arthritis↗
PubMed1989

[Clinical experience in diabetes and pregnancy].

We followed patients with pregnancy and diabetes in an outpatient clinic. 240 had gestational diabetes, 16 had type II and 5 type I diabetes. 85% of 110 patients with gestational diabetes had normal glucose tolerance test post partum (AGT). Type I patients were younger (25 years old) than AGT (32) or type II (33) patients. Complications frequently observed among diabetics included hypertension, premature membrane rupture and polyhydroamnios (the latter only among AGT and type II patients). Insulin was required for diabetes control in 14% of cases. Cesarean section was more frequent in diabetics than in a control population (21%): AGT 45%, type II 45% and type I 60%. Larger newborns occurred in 21% of AGT and 22% of type II as compared to 6% in controls. Neonatal mortality was 2.1% in AGT patients (0.8% in controls). Hyperbilirrubinemia, polyglobulia and hypocalcemia were more frequent among newborns of diabetic patients.

Adult↗
PubMed1989

Uremic plasma after infusion of desmopressin (DDAVP) improves the interaction of normal platelets with vessel subendothelium.

Effects of 1-deamino-8-D-arginine vasopressin (DDAVP; 0.4 microgram/kg iv) were studied in 11 patients with uremia. Bleeding time, platelet retention on glass beads, factor VIII activities, plasma catecholamine levels, and studies on platelet interaction with the subendothelium were performed before, 1 hour after, and 6 hours after DDAVP infusion. Perfusates consisting of normal washed platelets, uremic platelet-poor plasma (u-PPP) and washed red blood cells were perfused through the Baumgartner perfusion system at a shear rate of 800 sec-1. One hour after DDAVP infusion, a shortening in the bleeding time and an increase in platelet retention on glass beads were noticed in these patients (p less than 0.01). Simultaneously, plasma levels of noradrenaline, factor VIII coagulant (FVIII:C), and von Willebrand factor (vWF) activities were statistically increased. Platelet deposition and platelet aggregate formation on subendothelium were consistently increased (p less than 0.05) in perfusions carried out with blood reconstituted with u-PPP obtained 1 hour after DDAVP. The "in vitro" addition of 1 U/ml vWF or 1 U/ml vWF plus 1 U/ml factor VIII to the pretreatment u-PPP had no significant influence on the parameters that quantify platelet-subendothelium interaction. However, after the addition of 10 ng/ml noradrenaline to a similar system containing basal u-PPP, a clear improvement (p less than 0.05) in platelet deposition was noticed. Our results confirm the hemostatic effectiveness of DDAVP in patients with uremia and reveal an increased platelet interaction with subendothelium mediated by a factor present in uremic plasma after DDAVP administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Use of FMC macromolecular medium for determination of the erythrocyte ABO group using microtiter plates].

Several blood group determination techniques have been developed in recent years which provide easy handling, fine reproducibility and similar or even higher sensitivity than the procedures commonly employed, aimed to be used in the automation of blood bank work. A microtitration plate technique for ABO determination on red cells is presented in this report. A macromolecular medium, comprised of a mixture of the polymers Ficoll 400 and carboxymethyl cellulose (FMC) is used ad coadjuvant for the reaction. This medium increases by 15- the score units and by 4-fold (or more) the intensity of haemagglutination (titration) in typing the ABO antigenicity of red cell A, B, O and AB groups.

ABO Blood-Group System↗
PubMed1988

Asialo von Willebrand factor enhances platelet adhesion to vessel subendothelium.

Native von Willebrand factor (N-vWF) binds to platelets activated by thrombin, ADP or ristocetin. Asialo vWF (As-vWF) induces platelet aggregation in absence of platelet activators. N-vWF mediates platelet adhesion to vessel subendothelium at high shear rates. We have investigated the role of As-vWF in supporting platelet deposition to rabbit vessel subendothelium at a shear rate of 2,000 sec-1, using the Baumgartner perfusion system. We have studied the effects of the addition of As-vWF (from 2 to 12 micrograms/ml) to perfusates consisting of washed red blood cells, 4% human albumin and washed platelets. Our results show a significant increase in platelet deposition on subendothelium (p less than 0.01) in perfusions to which As-vWF had been added. Blockage of the platelet glycoproteins Ib and IIb/IIIa (GPIb and GPIIb/IIIa) by specific monoclonal antibodies (LJIb1 and LJCP8, respectively) resulted in a decrease of platelet deposition in both types of perfusates prepared with N-vWF and As-vWF. Our results indicate that As-vWF enhances platelet deposition to vessel subendothelium under flow conditions. Furthermore, they suggest that this effect is mediated by the binding of As-vWF to platelet membrane receptors, which in turn, promote platelet spreading and adhesion to the subendothelium.

Antibodies, Monoclonal↗