The role of HLA variation in lymphoma aetiology and survival.

Epidemiologic and laboratory evidence has consistently supported a strong inflammatory and immune component for lymphoma aetiology. These studies have consistently implicated variation in the immune gene, human leucocyte antigen (HLA), to be associated with lymphoma risk. In this review, we summarize the historical and recent evidence of HLA in both lymphoma aetiology and survival. The recent momentum in uncovering HLA associations has been propelled by the conduct of genome-wide association studies (GWAS), which has permitted the evaluation of imputed HLA alleles in much larger sample sizes than historically feasible with allelotyping studies. Based on the culmination of smaller HLA typing studies and larger GWAS, we now recognize several HLA associations with Hodgkin (HL) and non-Hodgkin lymphomas (NHLs) and their subtypes. Although other genetic variants have also been implicated with lymphoma risk, it is notable that HLA associations have been reported in every NHL and HL subtype evaluated to date. Both HLA class I and class II alleles have been linked with NHL and HL risk. It is notable that the associations identified are largely specific to each lymphoma subtype. However, pleiotropic HLA associations have also been observed. For example, rs10484561, which is in linkage disequilibrium with HLA-DRB1*01:01˜DQA1*01:01˜DQB1*05:01, has been implicated in increased FL and DLBCL risk. Opposing HLA associations across subtypes have also been reported, such as for HLA-A*01:01 which is associated with increased risk of EBV-positive cHL but decreased risk of EBV-negative cHL and chronic lymphocytic leukaemia/small cell lymphoma. Due to extensive linkage disequilibrium and allele/haplotypic variation across race/ethnicities, identification of causal alleles/haplotypes remains challenging. Follow-up functional studies are needed to identify the specific immunological pathways responsible in the multifactorial aetiology of HL and NHL. Correlative studies linking HLA alleles with known molecular subtypes and HLA expression in the tumours are also needed. Finally, additional association studies investigating HLA diversity and lymphoma survival are also required to replicate initial associations reported to date.

The use of a cartilage decellularized matrix scaffold for the repair of osteochondral defects: the importance of long-term studies in a large animal model.

OBJECTIVE: To investigate the effect of decellularized cartilage-derived matrix (CDM) scaffolds, by itself and as a composite scaffold with a calcium phosphate (CaP) base, for the repair of osteochondral defects. It was hypothesized that the chondral defects would heal with fibrocartilaginous tissue and that the composite scaffold would result in better bone formation. METHODS: After an 8-week pilot experiment in a single horse, scaffolds were implanted in eight healthy horses in osteochondral defects on the medial trochlear ridge of the femur. In one joint a composite CDM-CaP scaffold was implanted (+P), in the contralateral joint a CDM only (-P) scaffold. After euthanasia at 6 months, tissues were analysed by histology, immunohistochemistry, micro-CT, biochemistry and biomechanical evaluation. RESULTS: The 8-week pilot showed encouraging formation of bone and cartilage, but incomplete defect filling. At 6 months, micro-CT and histology showed much more limited filling of the defect, but the CaP component of the +P scaffolds was well integrated with the surrounding bone. The repair tissue was fibrotic with high collagen type I and low type II content and with no differences between the groups. There were also no biochemical differences between the groups and repair tissue was much less stiff than normal tissue (P < 0.0001). CONCLUSIONS: The implants failed to produce reasonable repair tissue in this osteochondral defect model, although the CaP base in the -P group integrated well with the recipient bone. The study stresses the importance of long-term in vivo studies to assess the efficacy of cartilage repair techniques.

BREMSO: a simple score to predict early the natural course of multiple sclerosis.

BACKGROUND AND PURPOSE: Early prediction of long-term disease evolution is a major challenge in the management of multiple sclerosis (MS). Our aim was to predict the natural course of MS using the Bayesian Risk Estimate for MS at Onset (BREMSO), which gives an individual risk score calculated from demographic and clinical variables collected at disease onset. METHODS: An observational study was carried out collecting data from MS patients included in MSBase, an international registry. Disease impact was studied using the Multiple Sclerosis Severity Score (MSSS) and time to secondary progression (SP). To evaluate the natural history of the disease, patients were analysed only if they did not receive immune therapies or only up to the time of starting these therapies. RESULTS: Data from 14 211 patients were analysed. The median BREMSO score was significantly higher in the subgroups of patients whose disease had a major clinical impact (MSSS≥ third quartile vs. ≤ first quartile, P < 0.00001) and who reached SP (P < 0.00001). The BREMSO showed good specificity (79%) as a tool for predicting the clinical impact of MS. CONCLUSIONS: BREMSO is a simple tool which can be used in the early stages of MS to predict its evolution, supporting therapeutic decisions in an observational setting.

A whole-genome assembly of Drosophila.

We report on the quality of a whole-genome assembly of Drosophila melanogaster and the nature of the computer algorithms that accomplished it. Three independent external data sources essentially agree with and support the assembly's sequence and ordering of contigs across the euchromatic portion of the genome. In addition, there are isolated contigs that we believe represent nonrepetitive pockets within the heterochromatin of the centromeres. Comparison with a previously sequenced 2.9- megabase region indicates that sequencing accuracy within nonrepetitive segments is greater than 99. 99% without manual curation. As such, this initial reconstruction of the Drosophila sequence should be of substantial value to the scientific community.

The sequence of the human genome.

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

[Design and implementation of a national serum bank for the surveillance of exotic animal diseases in the Republic of Cuba]. / Diseño e instauración de un banco nacional de sueros para la vigilancia de enfermedades exóticas de los animales en la República de Cuba.

A serum bank for the surveillance of exotic diseases was designed in accordance with the provisions of the Information and Epizootiological Surveillance System in the Republic of Cuba. Sera were collected from imported animals, from sentinel animals used for monitoring target areas at biological risk and from animals located in high animal-density areas. Methodologies were developed for the selection and characterisation of target areas at biological risk and sentinel animal points, the collection and storage of serum samples and the management of the national animal serum bank. After developing the methodologies, the serum bank was established throughout Cuba. The national animal serum bank operates using a quality management system based on the recommendations of the World Organisation for Animal Health and the International Organization for Standardization.

Biologic and genetic characteristics of Toxoplasma gondii isolates in free-range chickens from Costa Rica, Central America.

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 144 free-range chickens (Gallus domesticus) from Costa Rica was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 60 (40.1%) of 144 chickens with titers of 1:5 in 16, 1:10 in 5, 1:20 in 2, 1:40 in 3, 1:80 in 5, and 1:160 or higher in 29. Tissues of all chickens were bioassayed for T. gondii in mice or cats. Hearts and brains of 52 chickens with titers of 1:5 or higher and 16 chickens with doubtful titers were pooled and bioassayed in mice. Tissues from 76 chickens with MAT titers of 1:10 or less were pooled and fed to three T. gondii-free cats. Fecal floats of cats were bioassayed orally in mice but were negative for T. gondii oocysts. T. gondii was isolated by bioassay in mice from 32 chickens with MAT titers of 1:10 or higher. All infected mice from 4 of the 32 isolates died of toxoplasmosis. Genotyping of these 32 isolates using polymorphisms at the loci SAG1, SAG2, SAG3, BTUB and GRA6 revealed five genotypes. Five isolates had type I alleles and one isolate had type III alleles at all loci. The rest 26 isolates contained the combination of type I and II or I and III alleles and were divided into three genotypes. None was found to have genotype II alleles at all five loci. This is the first report of genetic characterization of T. gondii isolates from Costa Rica, Central America.

Scanning electron microscopy of the final phase of the life cycle of Trypanosoma cruzi in the insect vector.

Scanning electron micrographs showed that both epimastigotes and metacyclic trypomastigotes of Trypanosoma cruzi are attached by the flagellum to the epithelium of the rectal gland of Triatoma dimidiata. The flagellates tended to cover the surface of the gland and there was a marked predominance of epimastigotes with a round posterior end. Reproduction and metacyclogenesis seem to take place in situ, the latter apparently by twisting and elongation of the epimastigotes. Metatrypomastigotes remain attached for some time, probably by a weaker mechanism which easily allows them to loosen, facilitating expulsion with the urine or feces.

[Alterations in the coagulation mechanisms of patients bitten by Bothrops asper (Terciopelo)]. / Alteración de los mechanismos de la coagulación en el envenenamiento por Bothrops asper (Terciopelo).

Blood from eighteen patients bitten by B. asper were studied for effects on coagulation. All showed alterations in the levels of fibrinogen and of factors II, V, VIII, IX, X and XI, as well as in anti-thrombin-III and plasminogen. The number of platelets and the concentrations of factors VII and XII did not show significant variations in comparison with the controls. The biological assay of fibrinogen, the quantitation of fibrinogen degradation products and of factor II and the general coagulation tests, such as prothrombin and partial thromboplastin times, showed a good correlation with the severity of the envenomation. In snakebites by B. asper there is a severe hypofibrinogenemia, with fibrin degradation by activation in the fibrinolytic system and with activation and consumption of factor II. Intramuscular emergency treatment with small quantities of antivenom did not prevent the above noted alterations in coagulation.

[Neutralization of local effects of Bothrops asper venom by polyvalent antivenin]. / Neutralization de los effectos locales del veneno de Bothrops asper por un antiveneno polivalente.

Neutralization of lethality, myonecrosis, hemorrhage and edema induced by Bothrops asper venom in mice was studied using the polyvalent antivenom produced in the Instituto Clodomiro Picado. The neutralizing effect (ED50) on each of these toxic activities varied; the neutralization of lethal and hemorrhagic effects being more effective than the neutralization of myonecrosis and edema. With independent inoculation of venom and antivenom, antivenom was not effective in neutralizing edema-forming activity. The myonecrotic effect was only partially neutralized when serum was given i.v. immediately after envenomation; however, antivenin effectively neutralized the hemorrhagic activity. The ineffectiveness of antivenom in neutralizing edema and myonecrosis could be partially explained by the rapid development of these effects. Hence, the time interval between envenomation and antivenom administration and the route of serum administration both play an important role in the neutralization of local effects.

Cochlear implantation in patients with compromised healing.

BACKGROUND: The indications for cochlear implantation (CI) are continually evolving and, as experience accumulates, the relative contraindications for CI continue to decrease. However, there is little information regarding CI in patients who may be considered to be at risk for poor wound healing due to immunosuppression or intercurrent disease. OBJECTIVE: To assess and report the complication rates, postoperative course, postimplant rehabilitation, and long-term performance of patients considered at risk due to presumably impaired healing capability. We hypothesized that these patients had outcomes similar to other implanted patients. METHODS: This is a retrospective chart review of 277 patients who have received CI at the University of Miami Ear Institute between 1990 and 1999. The clinical courses of 6 patients on immunosuppressive medications and 7 patients with diseases believed to be associated with poor healing are reported. RESULTS: Long-term follow-up (mean, 33 months) showed postoperative complication rates, performance, and rehabilitation compliance that were similar to published reports of noncompromised patients. CONCLUSION: CI of selected patients with potentially reduced healing capabilities is safe and effective.

Plasmodium pessoai sp. n. from two Costa Rican snakes.

A unique malaria parasite species was found in 1/1 Spilotes pullatus (Colubridae) and 1/70 Lachesis muta (Crotalidae) from the moist Atlantic lowland forests of eastern Costa Rica. It is distinguished by small, sausage-shaped gametocytes (x 10.4 by 4.6 mu), growing schizonts that often contain a noticeable digestive vacuole with the contents partially visible, and striking spherical or bouquet-shaped segmenters whose precise merozoite numbers are difficult to discern (about 22-32) because of an intensely staining magenta or rose-colored substance in the matrix of the surrounding vacuole.

Phenol degradation in horizontal-flow anaerobic immobilized biomass (HAIB) reactor under mesophilic conditions.

A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its potential use for phenol degradation. The HAIB reactor consisted of a bore-silicate tube (100 cm long; 5.04 cm diameter) filled with polyurethane foam matrices containing immobilized anaerobic sludge. Before being subjected to phenol, the reactor was fed with synthetic substrate at the influent chemical oxygen demand (COD) of 1,028 mg.l-1 achieving 98% of COD removal efficiency. Thereafter, phenol as the sole carbon source was added under step-increasing concentrations from 50 to 1,200 mg.l-1. Phenol degradation was evaluated by gas chromatographic analysis of influent and effluent samples. Process monitoring included determinations of pH, volatile acids, alkalinity and COD. The HAIB reactor was operated at a constant hydraulic detention time (HDT) of 12 hours. After 33 days with 50 mg/l of phenol in the influent, the reactor achieved 98% of COD removal efficiency. Successful phenol degradation (efficiency removal of 99%) occurred for influent concentrations of 100, 300, 600, 900 and 1,200 mg.l-1 after 148, 58, 47, 29 and 7 days, respectively. The predominance of Methanosaeta-like, rods and methanogenic cocci could be observed in all the operating conditions, besides the presence of phenol oxidizing microorganisms as irregular rods. The results indicate that phenol degradation at very high rates can be accomplished in HAIB reactors containing acclimatized biomass.

[Hyperhomocysteinemia-related cerebral venous thrombosis]. / Trombosis venosa cerebral en relación con la hiperhomocisteinemia.

INTRODUCTION: Moderate hyperhomocysteinemia is a causal risk factor for atherosclerosis and venous thromboembolism. Recent researches have tried to find out a causal relationship. However, only a small number of cases have been reported on hyperhomocysteinemia and cerebral venous thrombosis in the world medical literature. CASE REPORT: We present the case of a 21 years old woman, and oral contraceptives taker, who consulted for a one week clinical picture of biparietal headache, nausea and vomiting. Examination revealed bilateral papilledema, and subsequent CT scan, MRI and MR angiography showed thrombosis of the left lateral sinus. Immunologic tests (antinuclear antibodies, antiphospholipid antibodies) were negative. Hypercoagulability studies showed persistent homocysteine high levels. The patient improved and was discharged after treatment with anticoagulants and therapeutic measures against brain edema. DISCUSSION: The 70 percent of the patients with thrombosis of the cerebral venous sinuses present hypercoagulable states, including moderate hyperhomocysteinemia. Several mechanisms are proposed for venous thrombosis in hyperhomocysteinemia, homocysteine induced endothelial dysfunction between others. Otherwise, oral contraceptives can increase the risk of venous thrombosis in other prothrombotic conditions. Folic acid and vitamins supplementation therapy are commented.

[Therapeutic efficacy of ursodeoxycholic acid in persistent gallbladder lithiasis and persistent biliary sludge: preliminary results of a multicenter experience]. / Eficacia terapéutica del ácido ursodesoxicólico (AUDC) en litiasis vesicular persistente (LV) y barro biliar persistente (BBP): Resultados preliminares de una experiencia multicentrica.

A prospective and multicenter study was performed to determine the efficacy and tolerance of ursodeoxycholic acid (UDCA) in the treatment of gallstones and biliary sludge. Criteria for entry into the trial were radiolucent gallbladder stones; until 20 mm of size and visualization of the gallbladder by oral cholecystography. Too were treatment the patients with persistent biliary sludge (PBS) defined by the persistence of the biliary sludge in two consecutive echography along three months. Without severe gallbladder disease. Then daily UDCA doses of 600 mg were suminstred divided in two postprandial times for a six months period. The control to the treatment were: basal ultrasonography (US) of the gallbladder and by follow-up gallbladder US for six months; clinical examination every month and cholecystography before and after the treatment. Of 110 admitted patients, 19 (17%) stopped the treatment for no-medical reasons and 91 (83%) arrived to the and point. After six months of treatment, complete dissolution was observed in 50% of the patients (46/91), partial in the 43% (39/91) and failed the treatment in 6.5% (6/91) who presented high density stones for computed tomography, CT (greater than 60 UH). According to pattern of lithiasis dissolution was complete in 100% (22/22) of the patients with PBS; 71.4% (10/14) in microlithiasis and 25% (14/55) in macrolithiasis. Minor adverse effects were acidism in the 7.7% (7/91) and diarrhea in the 1.1% (1/91). In the other hand, one patient presented acute pancreatitis (1/91; 1.1%), it must be discussed if was a complication of the lithiasis or an therapeutic effect. The UDCA was a safe and effective treatment without lethality in PBS and in microlithiasis while in case of macrolithiasis must be standardized response criterion, for example density stones for CT.

[Analysis of the 50g glucose test at the National Institute of Perinatology]. / Análisis de la prueba de 50 gramos de glucosa en el Instituto Nacional de Perinatología.

Gestational diabetes (GD), is a common illness in our country, that is associated with high perinatal morbi-mortality. The objective of this study is to assess the utility of the 50 g glucose screen test (GST) to know the frequency of GD at the National Institute of Perinatology, for preventing the neonatal risks associated with this pathology. For that reason, we performed a one year prospective study including 144 pregnant patients between 24-28 weeks of gestation. All of the patients undergo the 50g GST, and those with results or = to 140 mg/dl were followed by the glucose tolerance test (GTT). This GTT was performed with 100g of glucose and then blood samples were taken at fasting time, later at 60-120-180 minutes respectively. Of the total of 144 patients, 33 (23%), resulted with a positive GST. The GTT confirms the GD in 10.7% of the patients, and an equal proportion of gestational alterations to the GTT was observed. It is concluded that the 50 g GST is the best screening test to identify alterations of the carbohydrate metabolism during pregnancy.

[Description of an economic and simple methods for the study of karyotyping in serpents]. / Descripción de un método simple y económico para el estudio de cariotipos en serpientes

We describe a method for the preparation of snake chromosomes in metaphase, based on the in vivo stimulation of leucocytes with crude phytohemagglutinin from Phaseolus lunatus and the in vitro blocking of mitosis with colchicine. It has the advantage of preserving the specimen alive without the complications of cell culture, and can be performed under field conditions.

[Carbohydrates of the venoms of Bothrops asper of Costa Rica. Quantitative study]. / Carbohidratos del veneno de Bothrops asper de Costa Rica. Estudio cuantitativo.

The venom of the Central American Bothrops asper, previously classified as B. atrox, is very rich in carbohydrates, both in the free state and forming a part of glycoproteins. It also contains neutral sugars (hexoses), methylpentoses, hexosamines and sialic acid. There is a significant difference in the quantity of carbohydrates in the venom of B. asper as compared to that of the South American B. atrox, thus further documenting the different taxonomic position of these two species.

[Comparative study of venoms of newborn and adult specimens of Bothrops asper]. / Estudio comparativo de venenos de ejemplares recién nacidos y adultos de Bothrops asper.

This paper is a comparative study of venoms of newborn and adult specimens of Bothrops asper from two Costa Rican populations: San Carlos, in the Atlantic versant and Puriscal in the Pacific. Comparison was on a basis of determination of the following effects: hemorrhage, myonecrosis, edema, proteolysis, hemolysis, and lethality, as well as neutralization of the lethal effect by polyvalent antivenom. Biochemical and immunochemical comparisons were done by means of electrophoresis, immunoelectrophoresis, and immunodiffusion. There are marked differences between newborn and adult venoms from both regions in electrophoretic and immunoelectrophoretic patterns, although the immunodiffusion plates showed an almost identical pattern. Venoms from newborn specimens are more proteolytic, hemorrhagic, edema-forming and lethal, whereas those of adult specimens are more hemolytic and induce a stronger myonecrotic action, characterized by a myolitic type of necrosis. Antivenom neutralizes the lethality of all venoms with similar ED50. Venoms of adult specimens from both regions showed a slight variation in the immunoelectrophoretic pattern, but a complete identity in immunodiffusion plates. Adult venoms from San Carlos are more hemorrhagic, and myonecrotic, whereas those of Puriscal are more proteolytic, having similar lethality, edema-forming activity, and hemolytic effect. The same differences were observed when venoms from newborn specimens from both populations were compared.