Ancestry of the major long-range regulatory site of the α-globin genes in the Portuguese population with the common 3.7 kb α-thalassemia deletion

BACKGROUND

The α-Major Regulatory Element (α-MRE), also known as HS-40, is located upstream of the α-globin gene cluster and has a crucial role in the long-range regulation of the α-globin gene expression. This enhancer is polymorphic and several haplotypes were identified in different populations, with haplotype D almost exclusively found in African populations. The purpose of this research was to identify the HS-40 haplotype associated with the 3.7 kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and determine its ancestry and influence on patients' hematological phenotype.

METHODS AND RESULTS

We selected 111 Portuguese individuals previously analyzed by Gap-PCR to detect the presence of the -α3.7del: 50 without the -α3.7del, 34 heterozygous and 27 homozygous for the -α3.7del. The HS-40 region was amplified by PCR followed by Sanger sequencing. Four HS-40 haplotypes were found (A to D). The distribution of HS-40 haplotypes and genotypes are significantly different between individuals with and without the -α3.7del, being haplotype D and genotype AD the most prevalent in patients with this deletion in homozygosity. Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are separated from these and found more closely related to the African population.

CONCLUSION

This study revealed for the first time an association of the HS-40 haplotype D with the -α3.7del in the Portuguese population, and its likely African ancestry. These results may have clinical importance as in vitro analysis of haplotype D showed a decrease in its enhancer activity on α-globin gene.

Synthesis of thermoelectric magnesium-silicide pastes for 3D printing, electrospinning and low-pressure spray

In this work, eco-friendly magnesium-silicide (Mg₂Si) semiconducting (n-type) thermoelectric pastes for building components concerning energy-harvesting devices through 3D printing, spray and electrospinning were synthetized and tested for the first time. The Mg₂Si fine powders were obtained through the combination of ball milling and thermal annealing under Ar atmosphere. While the latter process was crucial for obtaining the desired Mg₂Si phase, the ball milling was indispensable for homogenizing and reducing the grain size of the powders. The synthetized Mg₂Si powders exhibited a large Seebeck coefficient of ~ 487 µV/K and were blended with a polymeric solution in different mass ratios to adjust the paste viscosity to the different requirements of 3D printing, electrospinning and low-pressure spray. The materials produced in every single stage of the paste synthesis were characterized by a variety of techniques that unequivocally prove their viability for producing thermoelectric parts and components. These can certainly trigger further research and development in green thermoelectric generators (TEGs) capable of adopting any form or shape with enhanced thermoelectric properties. These green TEGs are meant to compete with common toxic materials such as Bi₂Te₃, PbTe and CoSb that have Seebeck coefficients in the range of ~ 290-700 μV/K, similar to that of the produced Mg₂Si powders and lower than that of 3D printed bulk Mg₂Si pieces, measured to be ~ 4866 μV/K. Also, their measured thermal conductivities proved to be significantly lower (~ 0.2 W/mK) than that reported for Mg₂Si (≥ 4 W/mK). However, it is herein demonstrated that such thermoelectric properties are not stable over time. Pressureless sintering proved to be indispensable, but difficultly achievable by long thermal annealing (even above 32 h) in inert atmosphere at 400 °C, at least for bulk Mg₂Si pieces constituted by a mean grain size of 2-3 μm. Hence, for overcoming this sintering challenge and become the silicide's extrusion viable in the production of bulk thermoelectric parts, alternative pressureless sintering methods will have to be further explored.

Evidence for epistatic gene interactions between growth factor genes in stroke outcome

BACKGROUND AND PURPOSE

Growth factors are thought to modulate neurological function in stroke recovery through effects in angiogenesis, neurogenesis, and neuroprotection.

METHODS

We tested the association of variants in the brain-derived neurotrophic factor (BDNF), fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor A (VEGFA) genes, and epistatic interactions between them, with functional outcome in a sample of 546 stroke patients.

RESULTS

While none of the tested genes was independently associated with stroke outcome, two significant gene-gene interaction models were identified. One model combined one BDNF and three FGF2 markers, with a global odds ratio (OR) (95% confidence interval [CI]) of 4.15 [2.86-6.04]. The second model included one FGF2 and two VEGFA markers with a global OR [95% CI] = 2.54 [1.76-3.67].

CONCLUSIONS

The results provide evidence for gene interactions in stroke outcome, highlighting the complexity of the recovery mechanisms after a stroke event.

Variants within the nitric oxide synthase 1 gene are associated with stroke susceptibility

OBJECTIVE

Animal studies have allowed important insights into the role of the nitric oxide synthase (NOS) enzymes in atherosclerosis and hypertension, as well as in stroke. In this study we tested the hypothesis that the NOS1 and NOS3 genes, respectively encoding neuronal NOS (nNOS) and endothelial NOS (eNOS), influence stroke susceptibility and outcome after a stroke event.

METHODS

We conducted a case-control association study in 551 ischemic stroke patients and 530 controls to assess the role of NOS1 and NOS3 variants in stroke susceptibility. The same genes were tested for association with stroke outcome in a subset of 431 patients.

RESULTS

Four NOS1 single nucleotide polymorphisms (SNPs) (rs2293050, rs2139733, rs7308402 and rs1483757) and four haplotypes were significantly associated with stroke susceptibility after adjusting for demographic, clinical and life-style risk factors, and correcting for multiple testing using the false discovery rate (FDR) method (SNPs: 0.004<(uncorrected)P<0.007 and 0.036<FDR q<0.048; haplotypes: 0.001<(uncorrected)P<0.010 and 0.018<FDR q<0.032). NOS1 variants were not associated with stroke outcome. We did not find any evidence for a role of the NOS3 gene in stroke susceptibility or outcome.

CONCLUSION

Our results highlight NOS1 as a susceptibility factor for stroke, but do not corroborate previous NOS3 association findings with stroke risk. nNOS is known to play a major role in atherosclerosis development and in blood flow regulation, and it is plausible that its influence in stroke may be mediated through these two main clinical risk factors.

Variants of the Matrix Metalloproteinase-2 but not the Matrix Metalloproteinase-9 genes significantly influence functional outcome after stroke

Background

Multiple lines of evidence suggest that genetic factors contribute to stroke recovery. The matrix metalloproteinases -2 (MMP-2) and -9 (MMP-9) are modulators of extracellular matrix components, with important regulatory functions in the Central Nervous System (CNS). Shortly after stroke, MMP-2 and MMP-9 have mainly damaging effects for brain tissue. However, MMPs also have a beneficial activity in angiogenesis and neurovascular remodelling during the delayed neuroinflammatory response phase, thus possibly contributing to stroke functional recovery.

Methods

In the present study, the role of MMP-2 and MMP-9 genetic variants in stroke recovery was investigated in 546 stroke patients. Functional outcome was assessed three months after a stroke episode using the modified Rankin Scale (mRS), and patients were classified in two groups: good recovery (mRS ≤ 1) or poor recovery (mRS>1). Haplotype tagging single nucleotide polymorphisms (SNPs) in the MMP-2 (N = 21) and MMP-9 (N = 4) genes were genotyped and tested for association with stroke outcome, adjusting for significant non-genetic clinical variables.

Results

Six SNPs in the MMP-2 gene were significantly associated with stroke outcome (0.0018<P < 0.0415), two of which survived the Bonferroni correction for multiple testing. In the subset of ischemic stroke patients, association of five of these SNPs remained positive (0.0042<P < 0.0306). No significant associations were found for the MMP-9 gene.

Conclusions

The results presented strongly indicate that MMP-2 genetic variants are an important mediator of functional outcome after stroke.

Kalirin: a novel genetic risk factor for ischemic stroke

Cerebrovascular and cardiovascular diseases are the leading causes of death and disability worldwide. They are complex disorders resulting from the interplay of genetic and environmental factors, and may share several susceptibility genes. Several recent studies have implicated variants of the Kalirin (KALRN) gene with susceptibility to cardiovascular and metabolic phenotypes, but no studies have yet been performed in stroke patients. KALRN is involved, among others, in the inhibition of inducible nitric oxide synthase, in the regulation of ischemic signal transduction, and in neuronal morphogenesis, plasticity, and stability. The goal of the present study was to determine whether SNPs in the KALRN region on 3q13, which includes the Ropporin gene (ROPN1), predispose to ischemic stroke (IS) in a cohort of Portuguese patients and controls. We genotyped 34 tagging SNPs in the KALRN and ROPN1 chromosomal region on 565 IS patients and 517 unrelated controls, and performed genotype imputation for 405 markers on chromosome 3. We tested the single-marker association of these SNPs with IS. One SNP (rs4499545) in the ROPN1-KALRN intergenic region and two SNPs in KALRN (rs17286604 and rs11712619) showed significant (P < 0.05) allelic and genotypic (unadjusted and adjusted for hypertension, diabetes, and ever smoking) association with IS risk. Thirty-two imputed SNPs also showed an association at P < 0.05, and actual genotyping of three of these polymorphisms (rs7620580, rs6438833, and rs11712039) validated their association. Furthermore, rs11712039 was associated with IS (0.001 < P < 0.01) in a recent well-powered genomewide association study (Ikram et al. 2009). These studies suggest that variants in the KALRN gene region constitute risk factors for stroke and that KALRN may represent a common risk factor for vascular diseases.

The changing pattern of tuberculosis and HIV co-infection in immigrants and Spaniards in the last 20 years

OBJECTIVES

To evaluate the impact of immigration on tuberculosis (TB)-HIV co-infection in Spain in a prospective cohort of HIV patients.

METHODS

Among 7761 HIV patients, we evaluated 1284 with at least one episode of TB between 1987 and 2006. Variables were compared between immigrants and Spaniards.

RESULTS

Incidence of TB decreased from 20 to five cases per 100 patient-years in 2006 (P<0.01) and was always higher in immigrants than in Spaniards. The proportion of immigrants increased, reaching almost 50% of both new cases of HIV and TB-HIV co-infection in 2006. In 34.4% of patients, TB and HIV infection were diagnosed within the same year; simultaneous diagnosis was more frequent in immigrants (83.3%vs. 16.7%, P<0.001). Mortality was associated independently with age [hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.01-1.05], TB diagnosis before 1996 (HR 2.6, 95% CI 1.8-3.6), use of highly active antiretroviral treatment (HR 0.494, 95% CI 0.37-0.66) and CD4 cell count at TB diagnosis (HR 0.996, 95% CI 0.995-0.997).

CONCLUSIONS

Immigrants have a major impact on the incidence of TB in HIV patients, slowing down the decreasing trend in Spain. Simultaneous diagnosis of the co-infection in immigrants reveals a need to intensify HIV case finding in immigrants in Spain.

Mitochondrial haplogroup H1 is protective for ischemic stroke in Portuguese patients

BACKGROUND

The genetic contribution to stroke is well established but it has proven difficult to identify the genes and the disease-associated alleles mediating this effect, possibly because only nuclear genes have been intensely investigated so far. Mitochondrial DNA (mtDNA) has been implicated in several disorders having stroke as one of its clinical manifestations. The aim of this case-control study was to assess the contribution of mtDNA polymorphisms and haplogroups to ischemic stroke risk.

METHODS

We genotyped 19 mtDNA single nucleotide polymorphisms (SNPs) defining the major European haplogroups in 534 ischemic stroke patients and 499 controls collected in Portugal, and tested their allelic and haplogroup association with ischemic stroke risk.

RESULTS

Haplogroup H1 was found to be significantly less frequent in stroke patients than in controls (OR = 0.61, 95% CI = 0.45-0.83, p = 0.001), when comparing each clade against all other haplogroups pooled together. Conversely, the pre-HV/HV and U mtDNA lineages emerge as potential genetic factors conferring risk for stroke (OR = 3.14, 95% CI = 1.41-7.01, p = 0.003, and OR = 2.87, 95% CI = 1.13-7.28, p = 0.021, respectively). SNPs m.3010G>A, m.7028C>T and m.11719G>A strongly influence ischemic stroke risk, their allelic state in haplogroup H1 corroborating its protective effect.

CONCLUSION

Our data suggests that mitochondrial haplogroup H1 has an impact on ischemic stroke risk in a Portuguese sample.

Economic evaluation of assistance to HIV patients in a Spanish hospital

BACKGROUND

Little is known about the global effects of HAART on the use of medical resources after the complete implementation of this therapy in Spain. This study was designed to determine the use of medical resources and the costs of health care for HIV-infected patients.

METHODS

All patients with HIV infection who came to our institution during the year 2002 were included in the study. We analyzed the global assistance data and pharmaceutical costs during the year. Costs were calculated based on a unitary cost for DRG and an officially assigned standard cost for outpatient clinic, visits to the day care unit and to the emergency room (ER), outpatient surgery, and total costs of pharmacy.

RESULTS

The total cost for HIV-related health care assistance was euro739,048. The cost related to admissions was euro150,766.60; euro8631 per first visit and euro49,199.40 per successive visit; euro5085.10 per day care unit; euro14,920 per outpatient surgery; euro7655.70 per ER visit; and euro491,342.40 per antiretroviral treatment. A significant proportion of the total outpatient assistance was given by physicians other than HIV specialists, namely, 63% of the costs attributed to the first visit and 41% per successive visit.

CONCLUSION

More than 50% of the costs of caring for HIV-infected patients are still attributed to antiretroviral therapy. Specialists other than infectious disease specialists provide a significant proportion of outpatient assistance. A method to control HIV costs is greatly needed.

Novel point mutation in exon 12 of the glucose-6- phosphate dehydrogenase gene: G6PD FLORES

In Portugal there are a wide variety of G6PD deficiency associated mutations. In an individual from the island of Flores of the Azorean archipelago, we report a new mutation in the G6PD gene that gives rise to a "moderate rate of G6PD deficiency" (12.6% of the normal activity) according to WHO criteria. Direct sequencing revealed a C-->A point mutation at position 1387 with the consequent substitution of an Argine by Serine. We designated this new mutation as G6PD FLORES. The mutation is associated with haplotype I ( - - + + - - ), using six intragenic RFLPs. This information may also be seen as contributing to the clarification of the genetic makeup of the Azorean population, founder mutations, and/or gene flow.

Genotyping of fimbrial adhesins in Escherichia coli strains isolated from Slovak piglets suffering from diarrhea

One-hundred sixty Escherichia coli isolates obtained from piglets with diarrhea from different parts of Slovakia were examined for the presence of genes coding for F4, F5, F6 and F41 fimbrial adhesins, and hemolytic activity. According to polymerase chain reaction tests 74 (46%) E. coli isolates were positive for primers that detected genes coding for fimbrial adhesins. Of these 74 isolates, 64 were positive for genes encoding for F4+, four for F5+, five for F6+, and one for both F41+ and F5+ adhesins.

[Multicenter cohort of patients with HIV infection in the Madrid south-eastern metropolitan crown (COMESEM): basis, organization and initial results]

BACKGROUND

In order to evaluate changes related to the effect of new anti-retroviral agents and preventive programs, cohort studies of patients with HIV in our environment are needed.

METHODS

Cohort study of patients diagnosed of HIV infection in the five hospitals included in the Madrid metropolitan south-eastern crown (COMESEM), which attend a population of 1,300,000 inhabitants.

RESULTS

A total of 5,532 patients had been recruited until August 2001 (with a follow-up of 34,227 patients-year). The male/female ratio was 3/1. As for the transmission mechanism, 72.9% were parenteral drug users (PDU), 13.7% heterosexuals (HTX) and 8% of males having sex with males (MSM). The maximal figure of diagnosis per year corresponded to 1991 for PDU, 1993 for MSM and 1995 for heterosexuals. A decline in the number of diagnosed patients was observed for all groups, but MSM showed an increase in the year 2001 for the first time. Notably, among HTX, a growing and sustained trend was observed of patients not born in Spain (0% in 1993 and 50% in 2001; p < 0.001).

CONCLUSIONS

Establishing a large cohort of HIV infected patients based upon medium-sized hospitals is possible. The analysis of data derived from this cohort allows the early detection of changes in the clinical and epidemiological profile of HIV infection.

[A cost-benefit evaluation of prenatal diagnosis performed at a referral center with a population with a genetic or abnormality risk]

Prenatal diagnosis (PND) has assistencial, psychological and economical consequences; it is very important to evaluate cost effectiveness for the population. A prospective study was done (longitudinal and descriptive) on a population referred to Maternidade Dr. Alfredo da Costa, divided into two groups. Group one with PND performed on proper time and second group a PND procedure performed on a adequate time. The general characterization, indications for reference and consequences were evaluated. The conclusions are that the indications for reference were correct and the diagnosis was effective in 17% of patients. Social, economical levels and multiparity were the most important factors affecting adequate PND. However concerning the results, the termination of pregnancy was more performed on the group 1 and more abnormalities were seen on the newborns of group 2.

[Follow-up of the patient with HIV infection: a hospital task?]

OBJECTIVE

To assess how often patients with HIV infection abandon treatment.

DESIGN

Longitudinal, prospective and observational study. SITE. Out-patient Hospital Clinic.

PATIENTS AND OTHERS PARTICIPANTS

The total number of patients with HIV infection treated between September 1989 and December 1990.

INTERVENTIONS

Assessment of the level of out-patient follow-up.

MEASUREMENTS AND MAIN RESULTS

The rate of abandonment of out-patient follow-up was determined, with "abandonment" defined as unexplained non-attendance for at least two consecutive appointments. Its possible correlations with sex, age and HIV risk behaviour was calculated. 182 patients (143 men and 39 women) with an average age of 30.1 (ds 8.62) were surveyed. The abandonment rate for the sample as a whole was 44%, with no difference as to sex. However the abandonment rate was higher in the group of patients addicted to drugs (DDA) (69%) than in non-DDA (25%) or in ex-DDA patients (6.5%). These figures reached high statistical significance (p less than 0.01 and 0.001 respectively.

CONCLUSIONS

The abandonment rate of out-patient hospital follow-up by HIV-infected patients appears extremely high, especially among drug addicts (DDA).

[Spontaneous pneumothorax and Pneumocystis carinii pneumonia. Something more than a casual association?]

The association of spontaneous pneumothorax and Pneumocystis pneumonia is not frequent. The medical literature reports a ratio between 0 and 5.7%. In 18 patients admitted in our hospital, in the last two years, and diagnosed of AIDS and Pneumocystis pneumonia, we observed two cases of pneumothorax spontaneous. They represent the 11%. In one of them spontaneous pneumothorax was the first manifestation and in the other a complication of the illness. It was not possible to isolate an agent different from Pneumocystis carinii. Considering the lack of predisposition factors and the previous clinical history, we think that Pneumocystis carinii is by itself the agent responsible of this complication. In view of this possibility, spontaneous pneumothorax in a patient who belongs to an AIDS' risk group will alert the clinician to the possibility of infection with Pneumocystis carinii.

Renal handling of uric acid in patients with recurrent calcium nephrolithiasis and hyperuricosuria

Hyperuricosuria is a frequent finding in patients with recurrent calcium nephrolithiasis (RCN) that has been related to purine overingestion . The influence of diet and the renal handling of uric acid were investigated in patients with RCN to assess the pathogenic mechanism of excessive urate excretion. Among 50 patients with recurrent nephrolithiasis 42 formed renal stones containing calcium and 9 of these 42 patients demonstrated concomitant asymptomatic hyperuricosuria while on a self-selected diet. Ingestion of a purine-free diet normalized the uric acid excretion in 4 of these 9 patients. The other 5 patients showed persistent hyperuricosuria while on a purine-free diet. In order to assess a possible dysfunction in the renal handling of uric acid, pharmacological tests were undertaken in these 9 patients. Pyrazinamide administration almost completely suppressed urate excretion, excluding a presecretory reabsorption defect. Urate excretion in response to probenecid administration was decreased in 4 patients and increased in 1. This finding is in accordance with a postsecretory reabsorption defect in the former and an augmented tubular secretion of urate in the latter. This study proves that both dietary factors and tubular transport defects are involved in patients with recurrent calcium nephrolithiasis and hyperuricosuria.

Renal tubular acidosis in recurrent renal stone formers

Renal tubular acidosis (RTA) is a well-known metabolic disturbance that may promote recurrent renal stone formation. However, its incidence, screening criteria and association with other lithogenic metabolic abnormalities are not established in recurrent nephrolithiasis. 10 of 50 consecutive recurrent renal stone formers had a persistent fasting morning urinary pH above 6.0 and/or a basal plasma bicarbonate concentration below 20.0 mM. Acid and alkaline loads disclosed RTA in 3 patients: 1 patient had incomplete type-1 distal RTA in addition to hyperoxaluria; a second patient showed complete type-2 proximal RTA, hyperoxaluria and renal hypercaliuria; and a third patient had incomplete proximal RTA without any other metabolic derangement. These results reinforce the importance of RTA as an isolated metabolic abnormality among recurrent renal stone formers. In addition, RTA appears to be more commonly associated with other lithogenic metabolic derangements than has been previously suspected. The extensive metabolic protocol used in this study provides a useful tool in the diagnosis and therapeutic considerations of recurrent nephrolithiasis.

Renal handling of uric acid in normal subjects by means of the pyrazinamide and probenecid tests

Pyrazinamide and probenecid tests were used to study the renal mechanisms for urate excretion in 10 normal subjects in the state of low serum uric acid levels (below 3.5 mg/dl), normal serum urate concentrations (between 3.6 and 6.4 mg/dl) and high serum uric acid levels (above 6.5 mg/dl). Presecretory reabsorption of urate was above 99% in all three conditions of uricemia, indicating that filtered urate is nearly completely reabsorbed in the proximal tubule regardless of serum uric acid concentrations. Urate secretion was significantly higher and postsecretory reabsorption was significantly lower when serum uric acid was raised than when serum urate levels were normal or low. The findings indicate that both urate secretion and postsecretory reabsorption play a role in urate homeostasis in states of hyperuricemia.