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Biomedical subjects

R Castillo

Publications and source records attributed to R Castillo.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Comparison of the sensitivity and specificity of the electrocardiography criteria for left ventricular hypertrophy according to the methods of Romhilt-Estes, Sokolow-Lyon, Cornell and Rodríguez Padial].

INTRODUCTION AND OBJECTIVES: Because left ventricular mass is associated with an increase in the risk of morbidity and mortality of cardiovascular diseases in the general population having the electrocardiogram as an accessible and inexpensive method for the diagnosis of left ventricular hypertrophy, we decided to calculate the sensitivity and specificity of 5 electrocardiographic criteria for the diagnosis of left ventricular hypertrophy and to compare the results of the original authors to ours. PATIENTS AND METHODS: 135 patients were evaluated; 46 patients were excluded by the following criteria: chronic obstructive pulmonary disease, complete left or right bundle branch block, cardiovascular ischemic disease or Wolf-Parkinson-White Syndrome. 89 patients remained and had an electrocardiogram performed applying the following criteria: Romhilt-Estes Point-Score system. Sokolow-Lyon (SV1 + RV5 or V6 > 3.5 mV) and (RaVL > 1.1 mV), Cornell and Rodríguez Padial. Left ventricular hypertrophy was defined by the Penn Convention Criteria. RESULTS: In our study we obtained the following results: a) Romhilt-Estes had a sensitivity of 12% and a specificity of 87%; b) Sokolow-Lyon (SV1 + RV5 or V6) had a sensitivity of 22% and a specificity of 79%; c) Sokolow-Lyon (RaVL) has a sensitivity of 18% and a specificity of 92%; d) Cornel had a sensitivity of 31% and a specificity of 87%, and e) Rodríguez Padial had a sensitivity of 82% and a specificity of 8%. There are similarities between our results and the authors's original ones. However, there are significant statistical differences between them (p < or = 0.01). CONCLUSION: Our conclusion is that these criteria have a low diagnostic value in the isolated interpretation of patients with left ventricular hypertrophy, and we need to integrate them with the whole medical history and physical examination.

Adult↗
PubMed1997

Anaphylactoid reactions due to nonsteroidal antiinflammatory drugs: clinical and cross-reactivity studies.

BACKGROUND: Anaphylactoid reactions due to nonsteroidal antiinflammatory drugs have been described. OBJECTIVE: To study the clinical characteristics of 21 patients with anaphylactoid reactions due to nonsteroidal antiinflammatory drugs and to determine the cross-reactivity to non-steroidal antiinflammatory drugs not involved in the previous reactions nor structurally related by means of single-blind, placebo-controlled drug challenges. PATIENTS AND METHODS: Twenty-one patients who exhibited clinical evidence of anaphylactoid reactions after nonsteroidal antiinflammatory drugs were recruited for the study at the time of admission in Emergency Unit of our Hospital, Single-blind, placebo controlled oral challenges with nonsteroidal antiinflammatory drugs (except those reported by the patient as being responsible for the previous reaction), were performed in all patients. RESULTS: Fifteen patients were woman and six man, with a mean age of 35.7 years (range 18 to 62 years). Thirteen patients (60%) were normal subjects without concomitant diseases. No increase in frequency of atopy in comparison to the general population was observed. Pyrazole derivatives were the most common nonsteroidal antiinflammatory drugs involved (71.3%). A tolerance to drugs included in drug challenge protocol was noted in all patients. CONCLUSION: In our population, pyrazole derivatives were the most common nonsteroidal antiinflammatory drugs involved in anaphylactoid reactions. Most patients appeared to be otherwise normal subjects without concomitant disease and no cross-reactivity with other non-steroidal antiinflammatory drugs not involved in the anaphylactoid reaction nor structurally related was found.

Administration, Oral↗
PubMed1997

Hemostasis in patients with severe von Willebrand disease improves after normal platelet transfusion and normalizes with further correction of the plasma defect.

BACKGROUND: A defective hemostatic effect of plasma concentrate infusion in patients with severe von Willebrand disease (vWD) has been ascribed to the absence of platelet von Willebrand factor (vWF) STUDY DESIGN AND METHODS: The role of platelet vWF in hemostasis of severe vWD was investigated. A plateletpheresis unit (4-5 x 10(11) platelets) from a normal compatible donor was transfused before any cryoprecipitate infusion to three type 3 vWD patients and to one patient with severe type 1 vWD with low levels of platelet vWF who required replacement therapy for bleeding episodes. Autologous platelets were transfused to one of the patients with type 3 vWD. RESULTS: Partial corrections of bleeding times (14-17 min vs. baseline >30 min) were observed in all patients after the transfusion of normal platelets. During cryoprecipitate infusion, bleeding times were normalized (<6 min), and bleeding episodes stopped when plasma levels of vWF activity ranged from 14 to 18 U per dL. Platelet interactions with the subendothelium increased in parallel with the correction of bleeding times. These results indicate that if approximately 20 percent of the total number of platelets have normal vWF antigen and if plasma vWF levels are at least 14 U per dL, then bleeding times will normalize and mucosal hemorrhages will stop. Transfusion of autologous platelets in one patient with type 3 vWD did not modify bleeding times or platelet adhesion on the subendothelium. CONCLUSION: The hemostatic effect of normal platelets in type 3 vWD seems to be related to the platelet vWF in the transfused platelets.

Bleeding Time↗
PubMed1997

Conservation of the 15-kilodalton lipoprotein among Treponema pallidum subspecies and strains and other pathogenic treponemes: genetic and antigenic analyses.

The 15-kDa lipoprotein of Treponema pallidum is a major immunogen during natural syphilis infection in humans and experimental infection in other hosts. The humoral and cellular immune responses to this molecule appear late in infection as resistance to reinfection is developing. One therefore might hypothesize that this antigen is important for protective immunity. This possibility is explored by using both genetic and antigenic approaches. Limited or no cross-protection has been demonstrated between the T. pallidum subspecies and strains or between Treponema species. We therefore hypothesized that if the 15-kDa antigen was of major importance in protective immunity, it might be a likely site of antigenic diversity. To explore this possibility, the sequences of the open reading frames of the 15-kDa gene have been determined for Treponema pallidum subsp. pallidum (Nichols and Bal-3 strains), T. pallidum subsp. pertenue (Gauthier strain), T. pallidum subsp. endemicum (Bosnia strain), Treponema paraluiscuniculi (Cuniculi A, H, and K strains), and a little-characterized simian isolate of Treponema sp. (Fribourg-Blanc strain). No significant differences in DNA sequences of the genes for the coding region of the 15-kDa antigen were found among the different species and subspecies studied. In addition, all organisms showed expression of the 15-kDa antigen as determined by monoclonal antibody staining. The role of the 15-kDa antigen in protection against homologous infection with T. pallidum subsp. pallidum Nichols was examined in rabbits immunized with a purified recombinant 15-kDa fusion protein. No alteration in chancre development was observed in immunized, compared to unimmunized, rabbits, and the antisera induced by the immunization failed to enhance phagocytosis of T. pallidum subsp. pallidum by macrophages in vitro. These results do not support a major role for this antigen in protection against syphilis infection.

Animals↗
PubMed1997

Desmopressin (DDAVP) enhances platelet adhesion to the extracellular matrix of cultured human endothelial cells through increased expression of tissue factor.

The effect of desmopressin (DDAVP) on thrombogenicity, expression of tissue factor and procoagulant activity (PCA) of extracellular matrix (ECM) generated by human umbilical vein endothelial cells cultures (HUVEC), was studied under different experimental conditions. HUVEC were incubated with DDAVP (1, 5 and 30 ng/ml) and then detached from their ECM. The reactivity towards platelets of this ECM was tested in a perfusion system. Coverslips covered with DDAVP-treated ECMS were inserted in a parallel-plate chamber and exposed to normal blood anticoagulated with low molecular weight heparin (Fragmin, 20 U/ml). Perfusions with run for 5 min at a shear rate of 800 s-1. Deposition of platelets on ECMs was significantly increased with respect to control ECMs when DDAVP was used at 5 and 30 ng/ml (p < 0.05 and p. < 0.01 respectively). The increase in platelet deposition was prevented by incubation of ECMs with an antibody against human tissue factor prior to perfusion. Immunofluorescence studies positively detected tissue factor antigen on DDAVP derived ECMs. A chromogenic assay performed under standardized conditions revealed a statistically significant increase in the procoagulant activity of the ECMs produced by ECs incubated with 30 ng/ml DDAVP (p < 0.01 vs. control samples). Northern blot analysis revealed increased levels of tissue factor mRNA in extracts from ECs exposed to DDAVP. Our data indicate that DDAVP in vitro enhances platelet adhesion to the ECMs through increased expression of tissue factor. A similar increase in the expression of tissue factor might contribute to the in vivo hemostatic effect of DDAVP.

Anticoagulants↗
PubMed1996

Intolerance to nonsteroidal antiinflammatory drugs: results of controlled drug challenges in 98 patients.

BACKGROUND: Controlled oral challenge is the only definitive way to detect the different clinical manifestations of intolerance to nonsteroidal antiinflammatory drugs (NSAIDs). OBJECTIVE: This study was carried out to describe the clinical manifestations of drug challenges in a population with histories of intolerance to NSAIDs. METHODS: Two-hundred forty subjects were included in a single-blind, placebo-controlled drug challenge protocol. RESULTS: Eighty patients exhibited a positive response to drug challenge: 52 had isolated periorbital angioedema, 13 had cutaneous rashes, eight had bronchial asthma (7 with associated periorbital angioedema), three had nasoocular reactions, and four had systemic anaphylaxis. In another 18 patients who were referred for treatment because of a reaction suggesting systemic anaphylaxis, the implicated drug was not given, but tolerance to other NSAIDs was found. The mean age of patients with isolated periorbital angioedema was significantly lower (p < 0.001) than that of the other groups of NSAID reactors. A significant increase (p < 0.001) in atopy was found among patients with isolated periorbital angioedema (100%) in comparison with other patients with NSAID intolerance (45.6%). NSAID cross-reactivity was a common finding, but cross-reactivity was not found in two cases of periorbital angioedema, one case of urticaria, one case of bronchial asthma, and 18 cases of systemic anaphylaxis. CONCLUSION: In atopic subjects, isolated periorbital angioedema constitutes the most frequent manifestation of NSAID intolerance. Such patients are younger than other NSAID reactors and commonly have intolerance to several NSAIDs.

Administration, Oral↗
PubMed1996

Effects of temporal lobe epilepsy on spatial and figural aspects of memory for a complex geometric figure.

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal sclerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE.

Adult↗
PubMed1996

Procoagulant effect of incompatible platelet transfusions in alloimmunized refractory patients.

The clinical effectiveness of platelet transfusion in refractory patients is still a subject of debate. We have evaluated the possible hemostatic effect of platelet transfusion in 16 alloimmunized thrombocytopenic patients whose platelet counts were less than 20,000/microliters. Platelet concentrates were always obtained by apheresis procedures from incompatible donors. The posttransfusion platelet recovery was greater than 15% only in 3 cases. In the first 6 patients, measurements of bleeding time performed immediately before transfusion were in all cases longer than 30 min and did not change significantly 10 and 60 min after platelet transfusions. In all patients, ex vivo perfusion experiments with Baumgartner's platelet adhesion model, using native nonanticoagulated blood, were performed immediately before and 10 and 60 min after transfusion. No difference in platelet deposition onto the subendothelial surface was observed after platelet transfusion. Unexpectedly, the deposition of fibrin on the subendothelial surface was statistically augmented in the posttransfusion studies. Quantification of thrombin-antithrombin complexes (TAT) in plasma showed statistically significant elevations (p < 0.01) in the posttransfusion samples (31.9 +/- 12.6 vs. baseline 5.8 +/- 1.7 ng/ml), not justified by TAT levels in the transfused material (2.3 +/- 0.17 ng/ml). Transfusion of incompatible platelets to refractory patients may activate coagulation mechanisms in the absence of an increase in peripheral platelet count.

Blood Group Incompatibility↗
PubMed1996

Correlation of medical and neurosurgical events with neuropsychological status in children at diagnosis of astrocytoma: utilization of a neurological severity score.

Neuropsychological studies of children who have brain tumors have yielded diverse results with respect to identifying factors that contribute to poor intellectual outcome. The purpose of this study was to evaluate the relationship between pre- and perioperative events, tumor-related factors, and the neuropsychological status of children diagnosed with astrocytoma. Events that could potentially be detrimental to neuropsychological outcome were quantified utilizing a new "neurological severity score." The Neurological Severity Score was developed as a research tool to test our hypothesis that ultimate intellectual outcome is a result of cumulative, interactive insults on the central nervous system. This study constitutes a first step in examining the predictive value of the Neurological Severity Score by evaluating its correlation with baseline neuropsychological status. Fifty-nine children who had astrocytoma (36 supratentorial and 23 infratentorial) received complete neurological and neuropsychological evaluations within 3 months of diagnosis. Each child's neurological history and examination results were scored by an independent observer using the Neurological Severity Score. Neuroimages obtained at diagnosis and at the time of neuropsychological testing were evaluated as well. For the group as a whole, memory, attention, and motor abilities were significantly below age-appropriate norms, whereas intelligence, language, and academic skills were preserved. Patterns of deficits were identified and related to tumor site. There were no significant differences in mean neuropsychological domain scores between groups based on gender, pre-versus post-operative status, ethnicity, tumor grade, or abnormalities on magnetic resonance imaging (MRI). The Neurological Severity Score was significantly inversely correlated with visual-spatial skills, memory, attention, performance IQ, and global IQ. In conclusion, among all the medical and neurological factors present at diagnosis, the neurological severity score had the highest correlation with neuropsychological scores. This instrument has promise as a research tool in investigations of the psychological effects of cancer and its treatment on children.

Achievement↗
PubMed1996

[The efficacy of excluding anti-HVC-positive donors by ELISA 2 in the prevention of posttransfusion hepatitis].

To assess the efficacy of blood donor screening with a second generation ELISA for the detection of anti HCV the incidence of post transfusion hepatitis was prospectively determined in 190 patients submitted to cardiovascular surgery. An increase greater than 100 U/l of transaminases of serum activity was detected in five patients (2.6%), being found in four patients at 3 months of the transfusion and in one patient at 6 months. Serologic markers for HAV, HBV, HCV, CMV and EBV were not identified in any of these cases of post transfusion hepatitis and it is therefore assumed that they may have been caused by an, as yet unidentified, agent. It is concluded that second generation ELISA screening for anti HCV is very effective in the prevention of post transfusion hepatitis C.

Adult↗
PubMed1996

Anaphylaxis to subcutaneous neutral protamine Hagedorn insulin with simultaneous sensitization to protamine and insulin.

We report an insulin-treated diabetic patient who suffered, in a 2-month period, three severe anaphylactic reactions immediately after self-administered subcutaneous injections of neutral protamine Hagedorn (NPH) human recombinant-DNA insulin. These reactions consisted of local and systemic symptoms, including dyspnea and hypotension. A simultaneous sensitization to human insulin and to protamine was demonstrated, both by skin tests and by the determination of serum specific IgE. Suspecting protamine allergy, we performed a test dose to human lente insulin with perfect tolerance. After a 1-year follow-up with lente-insulin treatment, no reactions have occurred, despite treatment interruptions. Therefore, protamine IgE-mediated allergy probably caused our patient's reactions. In conclusion, protamine sensitization should be ruled out in any patient with a history of reactions to subcutaneous protamine-containing insulins, even if insulin sensitization is present.

Adult↗
PubMed1995

Reticulated platelets in uremic patients: effect of hemodialysis and continuous ambulatory peritoneal dialysis.

Platelet RNA content can be detected by flow cytometry using thiazole orange staining to identify platelets recently released into the circulation. We studied platelet RNA content and platelet function in uremic patients under different treatment regimens. Four groups were studied: (I) 15 end-stage renal disease (ESRD) patients (10M/5F) on maintenance hemodialysis (HD); (II) 11 ESRD patients (6M/5F) on continuous ambulatory peritoneal dialysis (CAPD); (III) 8 patients with chronic renal failure managed conservatively (5M/3F); and (IV) 34 controls (20M/14F). A double color labeling technique using a phycoerythrin-tagged antibody against glycoprotein Ib (CD42b) and RNA labeling by thiazole orange was performed and read by flow cytometry. Aggregation studies were made in platelet-rich plasma using ADP, epinephrine, collagen, arachidonic acid, and ristocetin. In group I, samples were also obtained after HD. Platelet counts did not differ among the groups. Aggregation studies showed a lower response to ADP and ristocetin in the HD patients, but not in the CAPD or in the chronic renal failure patients. The percentage of platelets with high RNA content in group I was significantly lower than in controls (3.72 +/- 1.72% vs. 9.05 +/- 3.53%, P < 0.01), but was also lower than in the remaining groups (I vs. II P < 0.01, and I vs. III P < 0.01). No differences were seen in platelet RNA content among groups II (8.67 +/- 2.73%), III (9.14 +/- 3.04%) and IV. In group I, the percentage of reticulated platelets decreased further after HD (2.14 +/- 1.09%, P < 0.01). Aggregation studies showed a significantly lower response to ADP and ristocetin in group I (P < 0.05), but not in groups II or III in comparison with controls. Aggregation response to ADP and ristocetin decreased after HD (P < 0.05). In conclusion, HD may decrease the percentage of RNA-rich platelets through elimination of the younger and more active platelets and worsen the thrombopathy present in uremic patients.

Adult↗
PubMed1995

Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome: a multivariate analysis of factors predicting the response to plasma exchange.

The aim of this study was to investigate pretreatment prognostic factors that could be useful in predicting the response to plasma exchange in thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). Thirty-two patients with TTP/HUS, treated with plasma exchange at our institution from 1980 to 1994, were studied. The main clinical and laboratory data at the beginning of plasma exchanges were analyzed by the Cox stepwise logistic regression, applied to either treatment failure or death. Seventeen (53%) patients attained a complete remission and 22 (69%) survived (five in advanced renal failure and long-term hemodialysis). Longer delay in initiating plasma exchanges, presence of stupor or coma, and higher creatinine levels at the beginning of plasma exchanges were independent predictors of treatment failure. Stupor or coma at the beginning of plasma exchanges was the only predictor of mortality from unremitted TTP/HUS. Hemoglobin levels, platelet count, and LDH activity, traditionally envisaged as markers of disease activity, neither correlated with previous duration of TTP/HUS nor had any prognostic value. Early diagnosis of TTP/HUS and prompt initiation of intensive plasma exchange emerged from this study as the most effective interventions for improving the prognosis of TTP/HUS patients.

Adolescent↗
PubMed1995

Uraemic medium causes endothelial cell dysfunction characterized by an alteration of the properties of its subendothelial matrix.

Uraemic patients suffer from haemorrhagic disorders and accelerated atherosclerosis. To evaluate the possible role of the vessel wall in these haemostatic alterations associated with uraemia, we investigated the effect of a uraemic milieu on human endothelial cell (EC) cultures and the reactivity of the extracellular matrices (ECM) generated by these cells towards platelets. EC cultures were exposed to a pool of sera (20% in the culture medium) obtained either from uraemic patients or from normal donors, and the following parameters were evaluated: (1) EC viability (trypan blue exclusion test); (2) von Willebrand factor (vWF) levels in supernatants and associated with ECM; (3) the reactivity of EC and EC-derived ECM towards platelets, measured 'ex vivo' under flow conditions (5 min, wall shear rate 800 s-1); and (4) ultrastructure of the ECM. The viability of EC cultured in the presence of uraemic sera was similar to controls. Platelet interaction with ECM generated by EC exposed to uraemic sera was significantly reduced (P < 0.05). This decrease was mainly related to a reduction in platelet adhesion (9.8 +/- 1.9% vs 16.7 +/- 1.8% in controls, P < 0.02). VWF levels in supernatants and associated with ECM were similar to controls. Ultrastructural analysis of the ECM generated by EC exposed to uraemic sera revealed a deficient matrix. An increased removal of EC was observed in experiments in which EC cultured in the presence of uraemic sera were perfused with citrated blood. These results indicate that a uraemic milieu induces quantitative and qualitative changes in the vascular subendothelium, characterized by a less intrincate network of fibrils, as well as a decreased attachment of EC and reduced thrombogenicity to the ECM. These changes may represent another mechanism which contributes to the haemostatic dysfunction observed in uraemic patients.

Blood Platelets↗