RESUMO

Resumen Las técnicas empleadas para la detección del Helicobacter pylori (H. pylori) son no invasivas e invasivas. En estas últimas, la presencia del H. pylori se determina a partir de la tinción de hematoxilina-eosina (HE), prueba rutinaria, mientras que en pocas ocasiones se aplica la tinción de Warthin-Starry (WS) como coloración especial. Objetivo: identificar la presencia de H. pylori por medio de la coloración especial de la WS en biopsias de pacientes con gastritis crónica folicular, previamente negativas en la tinción HE. Materiales y métodos: se desarrolló un estudio de tipo descriptivo transversal, en un período de 12 meses. Se tomaron los bloques de parafina de las muestras de la mucosa gástrica de pacientes con diagnóstico de gastritis crónica e hiperplasia folicular. Además, se extrajo un corte histológico del mismo bloque, al cual se le aplicó HE y se determinó la presencia o ausencia de H. pylori. Así, de estar ausente, se tomó del mismo bloque un corte adicional y se aplicó WS. Esto se evaluó con el fin de identificar la existencia o no del bacilo. Resultados: se recolectaron 314 muestras; 209 fueron negativas y 105 fueron positivas para HE. El 45 % (94) de estas muestras fueron positivas respecto a la presencia del bacilo, al aplicar la segunda coloración, y el 55 % (115) de las muestras persistieron negativas. Conclusión: el hallazgo de H. pylori es significativamente alto al aplicar la coloración de WS a muestras cuyo estudio histológico evidenció la ausencia del bacilo en biopsias de la mucosa gástrica, especialmente en muestras con escasa cantidad de bacterias.

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Abstract Non-invasive and invasive techniques can be used for detection of Helicobacter pylori. An invasive technique identifies the bacteria through routine hematoxylin-eosin staining. Warthin-Starry stain is rarely used. Objective: Our objective was to identify H. pylori by Warthin-Starry staining of patient's biopsies with chronic follicular gastritis who had previously tested negative in hematoxylin-eosin staining. Materials and methods: This is a descriptive, cross-sectional descriptive study that was carried out over a period of 12 months. The study examined paraffin blocks of samples taken from the gastric mucosa of patients diagnosed with chronic gastritis and follicular hyperplasia. A histological section was extracted from a block and tested with hematoxylin-eosin staining for the presence or absence of H. pylori. If absent, an additional cut was taken from the same block and Warthin-Starry staining was used to retest for the presence of the bacteria. Results: Of the 314 samples collected, 209 tested negative, and 105 tested positive for H. pylori when hematoxylin-eosin staining was used. Of the 209 negative samples, 45% (94) tested positive when Warthin Starry stain was used, and 55% (115) still tested negative. Conclusion: Findings of H. pylori are significantly higher when Warthin Starry stain was used to test samples whose previous histological study had evidenced an absence of the bacillus, especially in samples with a small amount of bacteria.

Assuntos

Humanos , Masculino , Feminino , Helicobacter pylori , Gastrite , Hematoxilina , Hiperplasia , Bactérias , Mucosa Gástrica

RESUMO

BACKGROUND: Glycoprotein VI (GPVI), 60-65 kDa, is a major collagen receptor on platelet membranes involved in adhesive and signaling responses. Mice lacking GPVI have impaired platelet response to collagen and defective primary adhesion and subsequent thrombus formation. Complete or partial deficiency of GPVI in humans is a rare condition presenting as a mild bleeding disorder. The defect in most of the reported patients is acquired and associated with other diseases. To date, only two patients have been characterized at the molecular level who carry different compound heterozygous mutations in the GP6 gene. OBJECTIVE: To report four unrelated patients from non-consanguineous families who presented with mucocutaneous bleeding. They had absent platelet aggregation and (14) C-5-HT secretion with collagen, convulxin and collagen-related peptide. RESULTS: Flow cytometry and immunofluorescence-confocal microscopy showed an absence of GPVI in non-permeabilized platelets. All the patients had an adenine insertion in exon 6 (c.711_712insA), changing the reading frame and generating a premature 'stop codon' in site 242 of the protein. The mutation predicts the synthesis of the truncated protein before the trans-membrane domain, corresponding to a band of ≈49 kDa observed in western blots and in permeabilized platelets by immunofluorescence. Platelet mRNA from all the patients was sequenced and contained the corresponding adenine insertion. Heterozygous relatives had no pathological bleeding, normal response to collagen and convulxin and intermediate membrane expression of GPVI. CONCLUSIONS: The identification of four unrelated homozygous patients with an identical defect suggests that inherited GPVI deficiency is more frequent than previously suspected, at least in Chile.

Assuntos

Adenina/metabolismo , Transtornos da Coagulação Sanguínea/genética , Éxons , Glicoproteínas da Membrana de Plaquetas/genética , Adulto , Sequência de Bases , Criança , Chile , Códon sem Sentido , Primers do DNA , Feminino , Heterozigoto , Humanos , Masculino , RNA Mensageiro/genética , Adulto Jovem

RESUMO

Like other countries in the Americas, during its colonization Uruguay was the recipient of immigrants from several ethnic groups from Europe, as well as of enslaved Africans. After its independence in 1830, Basques were the first group of Europeans to arrive in the country. In this paper, we aim to contribute to the understanding of the process of integration of these migratory waves into the Uruguayan society. For that purpose, individuals of Basque origin from the city of Trinidad, Uruguay, were chosen to participate in this study. Particularly, we wanted to determine if Basque descendants in Uruguay remained relatively isolated or if they mixed with other ethnic groups. Mitochondrial DNA (mtDNA) of 60 self-identified Basque descendants, taken from a larger sample of subjects with Basque ancestors, was analyzed. The origin of mtDNA haplogroups was 77.8% European, 20.4% Amerindian, and 1.8% African, showing similar frequencies to other Uruguayan regions. Very few sequences showed a clear Basque origin, although other sources such as the Canary Islands are likely. Moreover, genetic distances clearly show that Basque descendants are genetically closer to other Uruguayan groups than to European populations, including Basques. It is possible to conclude that Basques and their descendants in the region of Trinidad did not remain isolated and that their marriage behavior was similar to that of other Uruguayan populations. However, to have a more accurate picture of the way Basques intermarried with other populations in Uruguay, new analyses are needed that take into account paternal lineages as well as biparental genetic markers.

Assuntos

Colonialismo/história , DNA Mitocondrial/genética , Emigração e Imigração/história , Etnicidade/genética , Genética Populacional/história , Haplótipos/genética , Emigração e Imigração/estatística & dados numéricos , Etnicidade/história , Etnicidade/estatística & dados numéricos , Feminino , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Espanha , Uruguai

RESUMO

Ni-doped SnO2 nanoparticles prepared by a polymer precursor method have been characterized structurally and magnetically. Ni doping (up to 10 mol%) does not significantly affect the crystalline structure of SnO2, but stabilizes smaller particles as the Ni content is increased. A notable solid solution regime up to ∼ 3 mol% of Ni, and a Ni surface enrichment for the higher Ni contents are found. The room temperature ferromagnetism with saturation magnetization (MS) ∼ 1.2 × 10 (- 3) emu g (- 1) and coercive field (HC) ∼ 40 Oe is determined for the undoped sample, which is associated with the exchange coupling of the spins of electrons trapped in oxygen vacancies, mainly located on the surface of the particles. This ferromagnetism is enhanced as the Ni content increases up to ∼ 3 mol%, where the Ni ions are distributed in a solid solution. Above this Ni content, the ferromagnetism rapidly decays and a paramagnetic behavior is observed. This finding is assigned to the increasing segregation of Ni ions (likely formed by interstitials Ni ions and nearby substitutional sites) on the particle surface, which modifies the magnetic behavior by reducing the available oxygen vacancies and/or the free electrons and favoring paramagnetic behavior.

RESUMO

Background: Factor V Leiden and G20210A mutation of prothrombin gene are two important genetic polymorphisms associated with an increased risk for thrombosis. Aim: To establish the prevalence of factor V Leiden and prothrombin G20210A mutation in the Chilean population and their association to venous and arterial thromboembolism. Material and methods: A case-control study was conducted where 149 patients with thrombosis (87 with arterial and 62 with venous thrombosis) confirmed by CAT-scan, electrocardiogram and cardiac enzymes or Doppler depending on the case, and 160 healthy blood donors were genetically analyzed for the presence of both polymorphisms. Results: Factor V Leiden mutation was found in 5.4% of patients and in 1.3% of healthy controls (p=0.04). Heterozygosity for G20210A prothrombin mutation was found in 5.4% of patients and in 2.5% of the control group (p=NS). When arterial and venous thrombosis were considered as separate entities, 4.6% of patients with arterial thrombosis and 6.5% with venous thrombosis presented factor V Leiden (p=NS). Likewise, 8.1% of patients with venous thrombosis and 3.5% of patients with arterial thrombosis had G20210A prothrombin mutation (p=NS). Conclusions: In non selected consecutive Chilean patients with arterial and venous thrombosis the frequency of factor V Leiden and prothrombin G20210A is less than we could expect from their prevalence in the general population.

Assuntos

Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fator V/genética , Polimorfismo Genético , Protrombina/genética , Trombose/genética , Estudos de Casos e Controles , Chile/epidemiologia , Predisposição Genética para Doença , Genótipo , Mutação , Razão de Chances , Reação em Cadeia da Polimerase , Fatores de Risco , Trombose/epidemiologia , Trombose Venosa/genética

RESUMO

BACKGROUND: Information about consanguinity in Uruguay is scarce and limited to the end of the 20th century. AIM: To determine the frequency and characteristics of consanguineous marriages, as well as chronological trends, in two Uruguayan cities over almost two centuries. SUBJECTS AND METHODS: We analysed 28,393 Roman Catholic Church marriage records and Diocesan consanguinity dispensations belonging to the cities of Melo (Northeast), and Montevideo (South), for the period 1800--1994. RESULTS: 633 (2.23%) marriages were consanguineous. Among them, first cousin marriages were the most common (58.8% of all consanguineous marriages, including double consanguineous), especially those where the bride and groom were related through their maternal side. During the first decades of the 19th century both regions showed low levels of consanguinity. Consanguinity reached its maximum during the mid-1800s and decreased significantly throughout the 20th century. The overall mean coefficients of inbreeding were moderate in both cases, being greater in the Northeast (alpha=0.00165) than in the South (alpha = 0.00089). CONCLUSIONS: The low level of consanguinity as well as the structure of consanguineous marriages (distribution by degrees) is similar to that found in other southern South American countries. Temporal trends are similar to those found in industrialized regions in Europe, with maximum inbreeding levels during the middle-late 19th century; however, the clear predominance of first cousin unions, differs from most of the data for European countries. Small differences between the two cities can be related to diverse facts, such as socio-economic conditions, ethnic origin, immigration, and sampling.

Assuntos

Consanguinidade , Casamento/história , Feminino , História do Século XIX , História do Século XX , Humanos , Masculino , Casamento/tendências , Sistema de Registros , Uruguai

RESUMO

Uruguay posee un sistema solidario de financiación de trasplante a través del Fondo Nacional de Recursos y del banco Nacional de Órganos y tejidos (BNOT). En el trasplante alogénico de médula ósea la compatibilidad HLA es una barrera biológica importante. Las frecuencias alélicas y haplotípicas HLA son utilizadas para determinar la probabilidad de encontrar un donante con un fenotipo particular HLA y para predecir el efecto de diversos esquemas de adjudicación basados en la compatibilidad en este sistema. El Laboratorio de Inmunogenética e Histocompatibilidad tipifica a todos los receptores y donantes del país. Se ha iniciado un programa cuyo objetivo central es organizar un sistema de registro, tipificación y búsqueda de donantes no relacionados a nivel nacional (SINDOME). Objetivos: analizar los receptores tipificados para trasplante de médula ósea (TMO) alogénico en nuestro servicio en el período enero 1997 - mayo 2002, y caracterizar la constitución genética del sistema HLA para 298 receptores. Material y método: en el lapso indicado se estudiaron 346 receptores y 1.083 donantes. Se realizó la tipificación HLA clase I por reacción de microlinfocitotoxicidad con anticuerpos monoclonales y la reversa, con nivel de resolución intermedio-alta. Se estimaron las frecuencias alélicas y haplotípicas en una muestra de 298 receptores. Resultados: de los 346 receptores de TMO estudiados en el marco del SINDOME, 58 por ciento es menor de 30 años. La relación donante-receptor fue de 3,13 pero sólo el 45 por ciento de los candidatos a trasplante tuvo un donante histocompatible. En el análisis del polimorfismo de HLA-A, -B, -DR en la muestra de 298 receptores se encontró que los alelos más prevalentes fueron A2 (28,97 por ciento), B35 812,49 por ciento) y DR04 (15,24 por ciento). Sólo para el locus HLA-DRB1 la desviación del equilibrio de Hardy-Weinberg fue altamente significativa. Los haplotipos más comunes fueron A2-B51 y A2-B7 para HLA-A, -B, A2-DR11 y A2-DR04 para HLA-A -DRB1, y el haplotipo B8-DR03 para HLA-B -DR. De los Haplotipos HLA-A -B -DRB1, HLA-A1 -B8 -DR03 y HLA-A2 -B51 -DR13 fueron los más frecuentes. Conclusión: nuestros resultados demuestran que el sistema HLA presenta una considerable heterogeneidad, con un enorme polimorfismo y una amplia distribución de haplotipos. La posibilidad de encontrar donantes compatibles para un subgrupo de jóvenes con enfermedades malignas sin donantes familiares es muy baja. (AU)

Assuntos

Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-DR/genética , Antígenos de Histocompatibilidade , Histocompatibilidade , Transplante de Medula Óssea , Transplante de Células-Tronco Hematopoéticas

RESUMO

We studied HLA DQB1 allele frequencies and the relative risk (RR) of various genotypes in 72 type 1 diabetic patients and 40 control individuals in Uruguay. This is a tri-racial (Caucasian, Black and Indo-American) mixed population. The products of the polymerase chain reaction amplifications were hybridized with oligonucleotides by allele-specific oligonucleotide reverse or dot blot methods. Significant differences between these two groups were observed only for allele DQB1*0302 (35, RR = 7.34, P<0.001). The frequency of the alleles carrying a non-aspartic acid residue at position 57 was significantly higher in the diabetic patients (85 vs 53, P<0.001). In contrast, the frequency of Asp alleles was negatively associated with type 1 diabetes (RR = 0.20, P<0.001). The genotype DQB1*0302/DQB1*0201 (33, RR = 5.41, P<0.05) was positively associated with this disease. The genotype frequencies associated with type 1 diabetes in our population were significantly different from what is known for Caucasian and Black populations as well as compared with another admixed population, from Chile

Assuntos

Humanos , Masculino , Feminino , Criança , Antígenos HLA-DQ/genética , Diabetes Mellitus Tipo 1 , Predisposição Genética para Doença , Alelos , Estudos de Casos e Controles , Diabetes Mellitus Tipo 1 , Frequência do Gene , Uruguai

RESUMO

Salicylic acid (SA) activates immediate early transcription of genes controlled by a family of DNA promoter elements named as-1-like elements. These elements are functional in the promoter of glutathione S-transferase genes. We have previously shown that SA increases the binding of tobacco (Nicotiana tabacum cv Xanthi nc) nuclear factors to the as-1 sequence in a process mediated by protein phosphorylation. In this study we give evidence for the participation of a nuclear protein kinase CK2 (casein kinase 2) in the pathway activated by SA in tobacco. The first line of evidence comes from the evaluation of the CK2 activity in nuclear extracts prepared from tobacco plants treated with SA or water as a control. Results from these experiments indicate that SA increases the nuclear CK2 activity. The second line of evidence derives from the evaluation of the in vivo effect of 5,6-dichloro-1-(beta-D-ribofuranosyl) benzimidazole (DRB), a cell-permeable CK2 inhibitor, on the responsiveness of the as-1 sequence to SA. Results from these experiments indicate that DRB impairs the activating effect of SA on the transcription of both, the GUS reporter gene controlled by a tetramer of the as-1 element, and the endogenous gnt35 gene encoding a glutathione S-transferase, in transgenic tobacco plants. DRB also impaired the increasing effect of SA on the binding of nuclear factors to the as-1 element. Furthermore, transcription of the as-1/GUS reporter gene activated by the synthetic auxin 2,4-dichlorophenoxyacetic acid and by methyl jasmonate was also inhibited by DRB. To our knowledge, this is the first report in which activation of a CK2 enzyme by a plant hormone is reported.

Assuntos

Núcleo Celular/enzimologia , Nicotiana/enzimologia , Proteínas Serina-Treonina Quinases/metabolismo , Ácido Salicílico/farmacologia , Sequência de Aminoácidos , Sequência de Bases , Sítios de Ligação , Caseína Quinase II , Primers do DNA , Glucuronidase/genética , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Folhas de Planta/enzimologia , Proteínas Serina-Treonina Quinases/química , Nicotiana/efeitos dos fármacos , Nicotiana/genética , Ativação Transcricional

RESUMO

A polarographic DC(tast) method with the static mercury drop electrode, SMDE, was developed for determination of the flotation collector ethyl xanthate (EtX) in the concentration range from 1x10(-5) to 8x10(-5) M. The potentiality of the method was demonstrated by evaluating the capacity of powdered galena ore (PbS) to adsorb EtX in a titration-like procedure. Sulfide could be determined simultaneously with EtX because in NaOH electrolyte their anodic waves are well separated (E(1/2) congruent with-0.72 and -0.42 V versus Ag/AgCl, respectively). In addition, a new FIA method was developed by adapting a simple device to the tip of the glass capillary of a mercury electrode and doing amperometric detection at a fixed potential of -0.1 V, always in the DC(tast) mode. No oxygen removal was required. Reproducible results were obtained at a frequency of 72 injections per h, with automatic renewal of the SMDE every second. The calibration curve for freshly prepared EtX standards rendered a straight line from 5x10(-6) to 8x10(-5) M with correlation coefficient of 0.997, suitable for real applications in flotation processes and its effluents.

RESUMO

Thrombocytopenia is a major adverse effect of several drug treatments. Rifampicin has been recognized as a cause of immune thrombocytopenia during intermittent high-dose therapy. We characterized the antibody of a patient who presented with purpura and thrombocytopenia during treatment of tuberculosis with rifampicin. Drug-dependent binding of the antibody to platelets was demonstrated by flow cytometry. In a glycoprotein-specific immunoassay, the binding epitope of the IgG antibody was found in the glycoprotein Ib/IX complex, using four different monoclonal antibodies (mAbs) against various epitopes on the GPIb/IX complex, as well as mAbs against GPIIb/IIIa, GPIa/IIa and GPIV. By immunoprecipitation of biotin-labelled platelets, reactivity of the antibody with GPIb/IX was found only in the presence of the drug. These findings clearly demonstrate that rifampicin induces the formation of drug-dependent antibodies capable of causing thrombocytopenia. The binding site of the rifampicin-dependent antibody, located in the GPIb/IX complex, seems to be a favoured target for antibodies induced by different drugs.

Assuntos

Antibióticos Antituberculose/efeitos adversos , Epitopos/metabolismo , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Púrpura Trombocitopênica Idiopática/induzido quimicamente , Rifampina/efeitos adversos , Adulto , Anticorpos Monoclonais/metabolismo , Reações Antígeno-Anticorpo , Plaquetas/imunologia , Mapeamento de Epitopos , Citometria de Fluxo , Humanos , Imunoglobulina G , Masculino , Testes de Precipitina , Púrpura Trombocitopênica Idiopática/metabolismo

RESUMO

PURPOSE: To evaluate the catalytic activity of the red cell enzyme, glutathione reductase (GR) in pregnant women with Hb AS and with Hb AA, and in a group of non-pregnant women with Hb AA, as well as the relationship of GR deficiency with Hb S. PATIENTS AND METHODS: The catalytic activity was determined in presence and absence of FAD by means of a modified Long and Carson technique. 59 pregnant women with AS and 33 with AA phenotypes were studied. RESULTS: Differences were found in the enzyme's catalytic activity with and without FAD, both in pregnant women with Hb AS (mean values 37.17 nka/g y Hb in whites and 42.84 nkat/g HS in afro people) and in those with Hb AA, and also in non-pregnant women with Hb AA. A high frequency of GR deficiency was found in all groups due to an insufficient riboflavin supply in diet. CONCLUSION: A correlation between GR deficiency and Hb S could not be demonstrated. The coefficient of activity of red cell GR shows a tendency to increase in pregnancy due to certain riboflavin deficit of diet.

Assuntos

Eritrócitos/enzimologia , Glutationa Redutase/sangue , Complicações Hematológicas na Gravidez/sangue , Gravidez/sangue , Traço Falciforme/sangue , Adulto , População Negra/genética , Catálise , Cuba/epidemiologia , Dieta , Feminino , Flavina-Adenina Dinucleotídeo/sangue , Hemoglobina A/análise , Hemoglobina Falciforme/análise , Humanos , Fenótipo , Complicações Hematológicas na Gravidez/epidemiologia , Deficiência de Riboflavina/sangue , Deficiência de Riboflavina/complicações , Deficiência de Riboflavina/epidemiologia , Traço Falciforme/complicações , Traço Falciforme/epidemiologia , População Branca/genética

RESUMO

The case of a 49 yr old alcoholic women with clinical and laboratory findings that suggested a Cushing syndrome is presented. The functional tests showed cortisol suppression greater than 50% of the basal value with 8 mg of dexamethasone and no response in the combined dexamethasone/desmopressin test. Pituitary Nuclear Magnetic Resonance (NMR) was negative, Abdominal Computed Axial Tomography suggested hyperplastic adrenal glands; adrenal nodules were not found in the NMR. Pituitary or hipothalamic Cushing with secondary autonomous micronodular adrenal hyperplasia was suspected. Norcholesterol-I131 SPECT scintigraphy under dexamethasone suppression demonstrated a functional adrenal hyperplasia which was hystologically confirmed.

Assuntos

19-Iodocolesterol/análogos & derivados , Córtex Suprarrenal/diagnóstico por imagem , Síndrome de Cushing/diagnóstico por imagem , Glândulas Suprarrenais , Síndrome de Cushing/etiologia , Feminino , Humanos , Pessoa de Meia-Idade , Hipófise , Tomografia Computadorizada de Emissão de Fóton Único

RESUMO

Backgrour: Neonatal alloimmune thrombocytopenia (NAIT) is a result of fetomaternal incompatibility. Platelet destruction is caused by a maternal alntibody directed against a fetal platelet antigen inherited from the father and lacking on the mother's platelets. The incidence and features of transplacental alloimmunization depend on the frequency of expression of platelet specific antigens, which are highly variable among different populations. Aim: To determine the prevalence and characteristics of transplacental alloimmunization in a large, group of pregnant women in Chile. Material and methods: We, studied 3,041 samples obtained during the third trimester of gestation. In all samples, anti platelet antibodies were screened by ELISA with platelet membranes fixed to a microtiter plate. Positive samples were further studied for antigenic specificity with the monoclonal antibody specific immobilization of platelet antigens (MAIPA) test. Results: Anti platelet antibodies were found in 261 samples (8.5 percent). The MAIPA test identified 6 samples with antibodies directed against major platelet membrane glycoproteins, 2 anti GPIb, 2 anti GPIIb/IIIa and 2 anti GPIa/IIIa. In four cases, anti HLA antibodies coexisted. Two cases corresponded to well defined platelet antigen systems: one anti HPA-1a and one anti HPA-5b. No clinical evidence of thrombocytopenia of the newborn was detected in all these cases with anti GP antibodies. Conclusions: A prevalence of platelet specific antibodies of 0.2 por ciento with only one anti HPA-1a was detected. These findings are in contrast with those of other populations but in accordance with the low frequency of the HPA-1b/b phenotype in the Chilean population. The very low incidence of platelet specific antibodies and the lack of association with clinical thrombocytopenia in the newborn, do not support the recommendation of routine antenatal screening to all women in Chile

Assuntos

Humanos , Feminino , Gravidez , Terceiro Trimestre da Gravidez/sangue , Imunidade Materno-Adquirida/fisiologia , Tolerância Imunológica/fisiologia , Ensaio de Imunoadsorção Enzimática , Western Blotting , Especificidade de Anticorpos/imunologia , Antígenos de Plaquetas Humanas/isolamento & purificação , Complicações Hematológicas na Gravidez/diagnóstico , Diagnóstico Pré-Natal/métodos , Glicoproteínas da Membrana de Plaquetas/análise , Isoantígenos/isolamento & purificação

RESUMO

Background: Refractoriness continues to he a major complication of platelet transfusion therapy in patients with multiple transfusions: Despite most cases are secondary to non-immune causes, the most serious is that associated to alloimmunization. The incidence and consequences of HLA and non-HLA (platelet specific) antibodies are unknown in our country. Aim: To prospectively determinate the frequency and characteristic of post transfusion alloimmunization and the incidence of platelet specific antibodies. Patients and methods: Forty one adults and 24 children with a recently diagnosed malignancy and undergoing chemotherapy that required multiple transfusions were studied. Screening for antiplatelet antibodies (platelet membrane ELISA) was performed before the first transfusion, every four weeks or whenever the 1 hour corrected count increment for platelet transfusions was lower that 5000. Platelet specific antibodies werw identified with a monoclonal antibody-specific immobilization of platelet antigens (MAIPA), with anti-GPIIb, GPIIb/IIIa, GPIa/lia and anti-HLA class I. Results: Adult patients received an averafge of 10.2 ñ 5.5 units of red blood cells and 58.6 ñ 35.4 units of platelets. Children received 4.8 ñ 3.7 units of red blood cells and 9.6 ñ 6.7 units of platelets. HLA antibodies appeared in 7 of 41 adult patients (17 percent), platelet specific alloantibodies were found in two patients (one anti GP Ia/IIa and one anti GP ib). Platelet refractoriness appeared in three alloimmunized patients. No Child had detectable serum antibodies during follow up. Conclusions: Platel transfusion refractoriness of immune origin occurs infrequently in our population and the presence of platelet antibodies does not mean that it will appear. The use of leukocyte depleted blood components to prevent refractoriness cannot be justified at this time

Assuntos

Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Adolescente , Adulto , Pessoa de Meia-Idade , Neoplasias Hematológicas/imunologia , Isoanticorpos/isolamento & purificação , Transfusão de Plaquetas/efeitos adversos , Anemia Refratária/imunologia , Formação de Anticorpos/imunologia

RESUMO

BACKGROUND: Neonatal alloimmune thrombocytopenia (NAIT) is a result of fetomaternal incompatibility. Platelet destruction is caused by a maternal antibody directed against a fetal platelet antigen inherited from the father and lacking on the mother's platelets. The incidence and features of transplacental alloimmunization depend on the frequency of expression of platelet specific antigens; which are highly variable among different populations. AIM: To determine the prevalence and characteristics of transplacental alloimmunization in a large group of pregnant women in Chile. MATERIAL AND METHODS: We studied 3,041 samples obtained during the third trimester of gestation. In all samples, anti platelet antibodies were screened by ELISA with platelet membranes fixed to a microtiter plate. Positive samples were further studied for antigenic specificity with the monoclonal antibody specific immobilization of platelet antigens (MAIPA) test. RESULTS: Anti platelet antibodies were found in 261 samples (8.5%). The MAIPA test identified 6 samples with antibodies directed against major platelet membrane glycoproteins, 2 anti GPIb, 2 anti GPIIb/IIIa and 2 anti GPIa/IIa. In four cases, anti HLA antibodies coexisted. Two cases corresponded to well defined platelet antigen systems: one anti HPA-1a and one anti HPA-5b. No clinical evidence of thrombocytopenia of the newborn was detected in all these cases with anti GP antibodies. CONCLUSIONS: A prevalence of platelet specific antibodies of 0.2% with only one anti HPA-1a was detected. These findings are in contrast with those of other populations but in accordance with the low frequency of the HPA-1 b/b phenotype in the Chilean population. The very low incidence of platelet specific antibodies and the lack of association with clinical thrombocytopenia in the newborn, do not support the recommendation of routine antenatal screening to all women in Chile.

Assuntos

Antígenos de Plaquetas Humanas/imunologia , Troca Materno-Fetal/imunologia , Púrpura Trombocitopênica/imunologia , Antígenos de Plaquetas Humanas/análise , Incompatibilidade de Grupos Sanguíneos/complicações , Incompatibilidade de Grupos Sanguíneos/imunologia , Chile , Feminino , Humanos , Incidência , Recém-Nascido , Gravidez , Prevalência , Púrpura Trombocitopênica/etiologia

RESUMO

BACKGROUND: Refractoriness continues to be a major complication of platelet transfusion therapy in patients with multiple transfusions. Despite most cases are secondary to non-immune causes, the most serious is that associated to alloimmunization. The incidence and consequences of HLA and non-HLA (platelet specific) antibodies are unknown in our country. AIM: To prospectively determine the frequency and characteristics of post transfusion alloimmunization and the incidence of platelet specific antibodies. PATIENTS AND METHODS: Forty one adults and 24 children with a recently diagnosed malignancy and undergoing chemotherapy that required multiple transfusions were studied. Screening for antiplatelet antibodies (platelet membrane ELISA) was performed before the first transfusion, every four weeks or whenever the 1 hour corrected count increment for platelet transfusions was lower than 5000. Platelet specific antibodies were identified with a monoclonal antibody-specific immobilization of platelet antigens (MAIPA), with anti-GPIb, GPIIb/IIIa, GPIa/Iia and anti-HLA class I. RESULTS: Adult patients received an average of 10.2 +/- 5.5 units of red blood cells and 58.6 +/- 35.4 units of platelets. Children received 4.8 +/- 3.7 units of red blood cells and 9.6 +/- 6.7 units of platelets. HLA antibodies appeared in 7 of 41 adult patients (17%), platelet specific alloantibodies were found in two patients (one anti GP Ia/IIa and one anti GP Ib). Platelet refractoriness appeared in three alloimmunized patients. No child had detectable serum antibodies during follow up. CONCLUSIONS: Platelet transfusion refractoriness of immune origin occurs infrequently in our population and the presence of platelet antibodies does not mean that it will appear. The use of leukocyte depleted blood components to prevent refractoriness cannot be justified at this time.

Assuntos

Anemia Aplástica/imunologia , Anemia Aplástica/terapia , Antígenos de Plaquetas Humanas/imunologia , Antígenos HLA/imunologia , Isoanticorpos/imunologia , Transfusão de Plaquetas/efeitos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Adolescente , Adulto , Idoso , Especificidade de Anticorpos/imunologia , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos

Assuntos

Acil Coenzima A/metabolismo , Coenzima A/metabolismo , Hipolipemiantes/farmacologia , Microcorpos/efeitos dos fármacos , Xenobióticos/farmacologia , Carcinógenos/farmacologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Fígado/enzimologia , Proteína Quinase C/metabolismo , Transdução de Sinais , Fatores de Tempo

RESUMO

Activated protein C resistance (APCR) or Factor V Leiden has been recently described as the most prevalent hemostatic abnormality associated with venous thrombosis. In patients with familial thrombophilia, the prevalence of APCR is 19-60% and around 20% in sporadic venous thrombosis. APCR is usually measured by the degree of prolongation of Activated Partial Thromboplastin Time (APTT) on patient's plasma, induced by addition of APC in comparison to normal plasma. At the molecular level the defect is caused by a single-point mutation in the gene for factor V (FV) (G1.691-->A), that predicts the replacement of Arg506 by Glutamine. This mutation makes activated factor V resistant to inactivation by APC. Since the prevalence of the defect is highly variable among different populations, the objective of this work was to study its frequency in our population and in patients with thrombophilia. We defined the normal range for APTT ratio (APTT + APC/APTT - APC) in a group of 73 healthy volunteers in whom the presence of FV Q506 mutation was searched using Mull enzyme digestion of PCR amplified genomic fragment containing the nucleotide 1.691. The lower limit of APTT ratio established in this group was 2.13. APCR was found in 6 out of 159 control subjects (3.8%) and in 14/50 (28%) of patients with thrombosis. In 13 cases as a single defect and in one associated to type I protein C deficiency. All the APCR patients and control subjects were heterozygotes by gene analysis. The results demonstrate that in our population APCR is also the most common defect associated with thrombosis, in accordance with a high prevalence in the population. The ability to screen for this defect will permit the identification of carriers that would benefit of preventive therapy at risk situations.

Assuntos

Fator V/genética , Proteína C/fisiologia , Sequência de Bases , Chile , Suscetibilidade a Doenças , Deficiência do Fator V/genética , Humanos , Dados de Sequência Molecular , Tempo de Tromboplastina Parcial , Mutação Puntual , Reação em Cadeia da Polimerase

RESUMO

Activated protein C resistance (APCR) or factor V leiden has been recently described as the most prevalent hemostatic abnormality associated with venous thrombosis. In patients with familial thrombophilia, the prevalence of APCR is 19-60 percent and around 20 percent in sporadic venous thrombosis. APCR is usually measured by the degree of prolongation of activated Partial Thromboplastin Time (APTT) on patient's plasma, induced by addition of APC in comparison to normal plasma. At the molecular level the defect is caused by a single-point mutation in the gene for factor V (FV) (G1.691-A), that predict the replacement of Arg506 by Glutamine. This mutation makes activated factor V resistant to inactivation by APC. Since the prevalence of the defect is highly variable among different populations, the objective of this work was to study its frequency in our population and in patients with thrombophilia. We defined the normal range for APTT ratio (APTT+APC/APTT-APC) in a group of 73 healthy volunteers in whom the presence of FV Q506 mutation was searched using Mnll enzyme digestion of PCR amplified genomic fragment containing the nucleotide 1.691. The lower limit of APTT ratio stablished in this group was 2.13. APCR was found in 6 out of 159 control subjects (3.8 percent) and in 14/50 (28 percent) of patients with thrombosis. In 13 cases as a single defect and in 1 associated to type I protein C deficiency. All the APCR patients and control subjects were heterozygotes by gene analysis. The results demonstrate that in our population APCR is also the most common defect associated with thrombosis, in accordance with a high prevalence in the population. The ability to screen for this defect will permit the identification of carriers that would benefit preventive therapy at risk situations

Assuntos

Humanos , Masculino , Feminino , Transtornos da Coagulação Sanguínea/diagnóstico , Proteína C-Reativa/antagonistas & inibidores , Tempo de Tromboplastina Parcial , Trombose/prevenção & controle , Transtornos da Coagulação Sanguínea/epidemiologia , Estudos de Casos e Controles , Deficiência do Fator V/genética , Deficiência do Fator V/epidemiologia