Thymic volume is associated independently with the magnitude of short- and long-term repopulation of CD4+ T cells in HIV-infected adults after highly active antiretroviral therapy (HAART)

Age is one of the main factors involved in the rapidity and the magnitude of CD4(+) T cell repopulation in human immunodeficiency virus (HIV)-infected patients on highly active antiretroviral treatment (HAART). Improved thymic function has been suggested as the main factor associated with CD4(+) T cell restoration after HAART. This work was undertaken to determine, among host factors, the predictor variable at baseline involved in the magnitude of short- and long-term recovery of CD4(+) T cells after HAART. HIV-RNA levels and CD4(+) T cell numbers were determined in 54 HIV-infected adults at baseline and at weeks 4, 12, 48 and 96 after HAART. T cell subpopulations were determined by flow cytometry, thymic volume by computed tomography, T cell receptor excision circle (TREC)-bearing cells by quantitative polymerase chian reaction (PCR) and interleukin (IL)-7 levels by enzyme linked immunosorbent assay at baseline. The phenotype of patients' isolates was determined by infecting GHOST cells expressing CCR5 and CXCR4. The possible interference of phenotype with thymic function was also analysed. Baseline thymic volume was associated independently with the magnitude of short- and long-term recovery of CD4(+) T cells after HAART, despite the patients' viral phenotype. The measurement of thymic volume before therapy may predict the magnitude of T cell increase. This result could have important clinical implications not only in HIV-infected patients, but also in other scenarios of T cell depletion such as bone marrow transplantation and chemotherapy.

TNF-376A marks susceptibility to MS in the Spanish population: A replication study

This study was designed as a reappraisal of the association between the TNF-376A promoter polymorphism and susceptibility to multiple sclerosis found in the Spanish population but not in other populations. With a new dataset of patients (n = 241) and control subjects (n = 288), the association was confirmed (p = 0.018). The authors' data suggest that this association is specific of the Spanish white (or related) population or, alternatively, that only studies in their population have the adequate statistical power because of the higher frequency of an extended, conserved haplotype carrying the TNF-376A allele.

Evolution of genotypic resistance to nucleoside analogues in patients receiving protease inhibitor-containing regimens

The prevalence of genotypic resistance to nucleoside analogues (NA) was examined using a line probe assay (LiPA, Innogenetics, Spain) and a point mutation assay to test for codon 151 polymorphism in plasma from 34 individuals who had been exposed to NA for longer than 1 year. The testing was repeated in the same population after 6 months of being on a new potent protease inhibitor (PI)-containing antiretroviral combination. Only nine (47%) of the 19 patients initially carrying the codon 41 mutation restored zidovudine wild-type (WT) virus population. Similarly, eight (33%) out of 24 carrying the codon 215 mutation restored the wild-type variant. Two subjects carrying codon 74 didanosine mutation reverted to wild-type genotype, as well as two (18%) out of 11 harbouring the codon 184 lamivudine-resistant variant. To conclude, the extent to which drug recycling might be of benefit in subjects showing a restoration of genotypic sensitivity to former drugs needs to be explored.

Changes in thymus volume in adult HIV-infected patients under HAART: correlation with the T-cell repopulation

An important thymus role has been suggested in T-cell repopulation after HAART in adult HIV-1 infected patients. Thymus volume increase after treatment has been described in HIV-1 infected children but not in adult patients. The objective of this work was to evaluate the effect of HAART on the thymic volume of adult HIV-1 infected patients and its relation with the T-cell repopulation. Twenty-one adult patients following 24 weeks under HAART were included in the study. All patients underwent a thoracic computed tomography (CT) evaluation for the measurement of thymic volumes at weeks 0, 12 and 24. Baseline thymus volume showed a significant correlation with the patient's age. Thymic volume significantly increased after 24 weeks of HAART. Besides, a significant correlation between changes in the thymus volume and changes in both total and naïve CD4+ cell counts was found. Only patients with increases > or =100 CD4+ cell counts after treatment significantly increased the thymic volume. These data show the first evidence of an early change in thymic volume of adult HIV-1 infected patients under HAART. This increase was related to the rise of both total and naïve CD4+ cell counts suggesting a functional role of thymic volume increase.

Validation of the Spanish version of the Perceived Stress Questionnaire

OBJECTIVE

To validate in Spanish the Perceived Stress Questionnaire (PSQ), a questionnaire to assess stress for research purposes in psychosomatic patients.

METHOD

The test was administered to a healthy population (N=174) of nursing students and health workers and to a clinical sample (N=80) of patients attending a psychiatric outpatient consultation.

RESULTS

Concurrent validity: General and Recent PSQ scores correlated high with trait anxiety (r=.65), moderate with depression (r=.46) and psychological disturbance (r=.51) and poor with state anxiety (r=.22). Predictive validity: PSQ scores were higher in "psychiatric cases" than in "psychiatric noncases" (P<.01), and correlated highly with somatic symptoms of psychological origin (r=.62) in the clinical subsample. Internal consistency was 0.9 for the General and 0.87 for the Recent PSQ. Test-retest reliability of the General PSQ was 0.80.

DISCUSSION

The Spanish version of PSQ presents good psychometric properties and it seems to be a valuable instrument for psychosomatic researchers.

Anomalous quasiparticle lifetime in graphite: band structure effects

We report ab initio calculations of quasiparticle lifetimes in graphite, as determined from the imaginary part of the self-energy operator within the GW approximation. The inverse lifetime in the energy range from 0.5 to 3.5 eV above the Fermi level presents significant deviations from the quadratic behavior naively expected from Fermi liquid theory. The deviations are explained in terms of the unique features of the band structure of this material. We also discuss the experimental results from different groups and make some predictions for future experiments.

Minimal liver injury in chronic hepatitis C virus infection is associated with low levels of soluble TNF-alpha/Fas receptors and acquisition in childhood

BACKGROUND/AIMS

The rate of progression to cirrhosis of chronic hepatitis C might be related to an upregulation of TNF-alpha/Fas pathways.

METHODS

The serum levels of soluble TNF-alpha type II receptor (sTNFr-II) and soluble Fas antigen (sFas) were analyzed in patients with different histological outcomes of chronic parenterally acquired HCV infection of similar duration.

RESULTS

One hundred and forty-five HCV-infected patients had a known duration of infection. Twelve (8.3%) patients had minimal changes and were assigned to the case group. The control group was selected from the 24 (17%) patients with cirrhosis and the 54 (37%) with chronic active hepatitis (CAH). Two controls, one with CAH and one with cirrhosis, were paired with the cases following these criteria: duration of infection, transmission route and sex. The proportions of genotype 1b and HCV RNA serum levels were similar among the groups. The median serum levels of sTNFr-II and sFas were significantly lower in the case group than in the control groups. The cases were significantly younger when they became infected than the control groups. Indeed, most cases were infected within the first 10 years of life. sTNFr-II and age at infection were independently associated with the minimal injury case group. When sTNFr-II was excluded from the logistic regression model, sFas and age at infection were independently associated with the case group.

CONCLUSION

The rate of progression of parenterally acquired chronic hepatitis C to end-stage liver disease might be related to an upregulation of the TNF-alpha/Fas pathways and an age-dependent host response.

[Usefulness of 201T1 gammagraphy in the diagnosis of carcinoma of the larynx]

For the evaluation of a patient with a laryngeal tumor we need the clinical exam and other exams as the CT scan or MRI. Those studies have a sensitivity of less than 80%. For that reason in the last years there has been a development of new techniques trying to increase the accuracy. The 201Tl SPECT is one of them although it was developed for cardiological purposes. We present our experience in 46 patients with laryngeal tumor in whom we did a 201Tl SPECT as part of the extension study. The sensitivity of the study was 81.6% in the diagnosis of the primary tumor and 46.1% for the neck adenopathies. The 201Tl SPECT can be a good method for the evaluation and detection of recurrences in patients with pharyngo-laryngeal tumor.

Changes in the rate of genotypic resistance to antiretroviral drugs in Spain

Genotypic resistance to antiretroviral drugs was examined in 684 individuals attending 18 outpatient clinics distributed across Spain in June 2000. Compared with similar surveys conducted before 1998, the prevalence of resistance to nucleosides has declined significantly among naive chronic HIV carriers. In contrast, resistance among pre-treated patients has increased; resistance to all three drug families having been recognized in nearly a quarter of patients.

Stochastic heterostructures and diodium in B/N-doped carbon nanotubes

Carbon nanotubes are one dimensional and very narrow. These obvious facts imply that, under doping with boron and nitrogen, microscopic doping inhomogeneity is much more important than for bulk semiconductors. We consider the possibility of exploiting such fluctuations to create interesting devices. Using the self-consistent tight-binding technique, we study heavily doped highly compensated nanotubes, revealing the spontaneous formation of structures resembling chains of random quantum dots, or nanoscale diodelike elements in series. We also consider truly isolated impurities, revealing simple scaling properties of bound state sizes and energies.

Drug resistance in patients experiencing early virological failure under a triple combination including indinavir

OBJECTIVE

To assess the pattern of drug resistance mutations selected in HIV-1-infected patients failing a first line triple combination therapy including indinavir.

PATIENTS AND METHODS

Plasma samples from 87 patients collected at the time of the first virological rebound (> 50 HIV-RNA copies/ml) were examined for the presence of drug-resistant genotypes.

RESULTS

The mean level of plasma viraemia at rebound was 7824 HIV-1 RNA copies/ml in 73 subjects with good compliance, whereas it was 359,460 HIV-1 RNA copies/ml in 14 patients who admitted to poor adherence. Genetic sequence analysis yielded results for 51 (70%) of the patients having good adherence. More than half of them (26/51, 51%) carried primary mutations associated with resistance to nucleoside analogues. In contrast, primary protease inhibitor resistance mutations were recognized less frequently (14/51, 27%; P < 0.05). Moreover, in 23 (45%) patients there was no evidence of drug-resistant viruses at all. The most frequent drug-resistant genotypes in the reverse transcriptase gene were at codons 184 (n = 19), 215 (n = 14) and 41 (n = 8), whereas for the protease they were at codons 46 (n = 10), 82 (n = 9) and 90 (n = 7). No resistance genotypes were found among non-compliant patients.

CONCLUSION

The overall rate of drug-resistant HIV genotypes was 38% (28/73) in patients with good adherence and who were experiencing a first virological failure under a triple combination regimen including indinavir; resistance to nucleoside analogues was more frequent than resistance to indinavir. Therefore, treatment intensification in those patients without resistance, or a selective substitution of nucleosides in those with resistance limited to these compounds, might be justified.

Primary association of a MICA allele with protection against rheumatoid arthritis

OBJECTIVE

To determine whether major histocompatibility complex class I chain-related gene A (MICA) polymorphisms are associated with susceptibility to rheumatoid arthritis (RA) independently of the HLA-DRB1 shared epitope (SE).

METHODS

Fifty-four Spanish families with an affected son or daughter and 211 consecutive RA patients were genotyped for HLA-DRB1, tumor necrosis factor a/b microsatellite alleles, and MICA transmembrane polymorphism. We performed a case-control comparison with the consecutive patients and an independent transmission disequilibrium test with the families.

RESULTS

The frequency of the MICA 6.0 allele was significantly reduced, compared with controls, in the group of SE+ patients (odds ratio 0.39, P = 0.0005). Additionally, the haplotypes containing this allele were preferentially not transmitted to the affected offspring (9 transmitted of 33; P = 0.007), independent of the presence or absence of an SE either in the same haplotype or in the other haplotype in the progenitor.

CONCLUSION

These data suggest that the MICA 6.0 allele is an independent marker of protection against RA in the SE+ group of RA patients.

Fluorescence resonance energy transfer analysis of CCR-V64I and SDF1-3'a polymorphisms: prevalence in southern Spain hiv type 1+ cohort and noninfected population

The relationship between host genotype and AIDS, as well as the different genotype frequencies observed in different populations, have become important topics in HIV research. Therefore, the development of methods that provide faster and reliable results may contribute to further development and knowledge of those topics. We present the results of genotyping SDF1-3'A and CCR2-V64I in 440 HIV-1-infected people and 100 noninfected controls from southern Spain, using a novel method based on real-time PCR with LightCycler technology and fluorescence resonance energy transfer. Frequencies obtained were 23.8% for SDF1-3'A and 9.5% for CCR2-V64I for both HIV+ cohort and general population. Both polymorphisms are in accordance with the Hardy-Weinberg equilibrium law and no differences between patients and controls have been observed.

Novel polygonized single-wall carbon nanotube bundles

We have synthesized novel crystalline ropes of "polygonized" single-wall carbon nanotubes (SWCNTs). The tubes exhibit rounded-hexagonal cross sections in contrast to the earlier observations of nearly circular tubes. To investigate the structural characteristics of the lattice of SWCNTs we have performed extensive molecular-dynamics simulations. We find several metastable structures of the lattice characterized by different tube cross sections, hexagonal, rounded-hexagonal, and circular, and increasing cell volume. The competition between different tube shapes as a function of tube diameter is analyzed and compared to experiments.

13C NMR chemical shift of single-wall carbon nanotubes

We compute the magnetic shielding tensor within the London approximation and estimate the Knight shift of single-wall carbon nanotubes. Our results indicate that high resolution 13C NMR should be able to separate the metallic and insulator character of the nanotubes since a 11 ppm splitting is predicted from the respective resonances. As a model for disorder, bending, and defects in these structures, we investigate the magnetic response of nanotubes with finite size. We get a small line broadening coming from an intrinsic length dependent resonance effect. The nanotube packing is also studied and leads to a 20 ppm broadening which disappears under experimental high-resolution conditions.

Usefulness of route of transmission, absolute CD8+ T-cell counts, and levels of serum tumor necrosis factor alpha as predictors of survival of HIV-1-infected patients with very low CD4 + T-cell counts

Potential cofactors of survival in HIV-1-infected patients with CD4+ T-cell counts of < or = 100 cells/microl were investigated. All 132 patients with CD4+ T-cell counts of < or = 100 cells/microl were selected from 416 patients included in an antiretroviral therapy cohort (1989-1999). Fifty of 54 deaths were due to AIDS. There were significant associations (P<0.05) between survival and CD8+ T-cell counts, clinical AIDS stage, risk group, and antiretroviral drug regimen after baseline, but only the use of protease inhibitors had an independent effect on survival (hazard ratio [HR], 0.096; 95% confidence interval [95%CI], 0.094-0.097). A substudy restricted to the cohort of 108 patients never exposed to PIs detected independent associations between survival and CD8+ T-cell counts (P=0.0016), experience with antiretroviral therapy before baseline (HR, 2.52; 95%CI, 1.31-4.82), sexual risk group for HIV infection (HR, 3.7; 95%CI, 1.92-7.12), and levels of serum tumor necrosis factor alpha (P=0.02). This study confirms that the use of PI-containing antiretroviral regimens strongly predicts survival of HIV-1-infected patients with very low CD4+ T-cell counts. When the study was restricted to patients never exposed to PIs, the parenteral route of disease transmission, high absolute CD8 + T-cell counts, and low serum levels of tumor necrosis factor alpha were independent predictors of survival in extremely advanced HIV-1 disease.