Relevance of HIV-1-specific CD4+ helper T-cell responses during structured treatment interruptions in patients with CD4+ T-cell nadir above 400/mm3

OBJECTIVES: To analyze the dynamics of both HIV-1-specific CD4 and CD8 T-cell responses during structured treatment interruptions (STIs) in chronically HIV-1-infected (CHI) patients and to correlate them with the viral set point achieved. METHODS: Forty-five early-stage CHI patients who were on highly active antiretroviral therapy (HAART) for at least 1 year and underwent STI were included. Plasma viral load (VL), peripheral blood mononuclear cell (PBMC) lymphoproliferative (LPR) response to HIV p24 protein, and HIV-1 epitope-specific interferon-gammarelease from CD8 T cells were measured over a minimum study period of 2 years. RESULTS: VL set point during final STI was both significantly lower than, and positively correlated to, baseline VL (P < 0.0001: mean VL reduction 0.77 log10, and r = 0.42, P = 0.004, respectively). CD4 LPRs to p24 increased significantly (P = 0.001) between day 0 of the first STI cycle and 4th STI but decreased thereafter. VL set point during final STI was significantly and negatively correlated with LPRs to p24 at both 2nd STI and 4th STI. Nevertheless, at week 52, 12 weeks after the end of the last STI, LPRs were weak and transient in all patients and were not correlated with VL set point. Moreover, the magnitude and breadth of HIV-1-specific CD8 T-cell responses increased significantly (P < 0.0001) between day 0 and week 52. The largest increases occurred during the final STI. Even though VL reached set point by week 12 of the final STI, HIV-1-specific CD8 T-cell responses did not stabilize but rather increased until the end of the follow-up and did not correlate with plasma VL (r = 0.01, P = 0.88). CONCLUSIONS: STIs do not lead to control of viral replication in CHI patients, probably due to the fact that boosted CTL responses lack strong and durable helper T-cell responses. To reset the VL set point, new approaches that effectively augment and preserve helper T-cell responses should be investigated.     

Towards improved clinical characterization of Leber congenital amaurosis: neurological and systemic findings

Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophy that presents in infancy. LCA is both clinically and genetically heterogeneous. The aim of our study was to clarify the clinical aspects of LCA and to contribute to improved characterization of the disorder. We studied 40 children affected by LCA (mean age at first observation: 19 months, range: 8-50 months), who underwent a comprehensive evaluation that included: neurophthalmological evaluation, electroretinogram (ERG), and visual evoked potentials (VEPs), general and neurological examinations, developmental assessment using scales for visually impaired children, neuroradiological examinations, hepatic and renal function and metabolic investigations, brainstem auditory evoked potentials (BAEPs), EEG, and hand radiographs. Analyses of known LCA genes are ongoing. The subjects are still being followed up at 6-/12-month intervals. All the subjects fulfilled De Laey's criteria for LCA. The neurological examination was abnormal in 31 cases (hypotonia, ataxia with/without associated cerebellar signs). Cognitive development was normal in 24 cases, borderline in five, and subnormal in 11. Mild and nonspecific alterations on MRI were present in seven cases, and "molar tooth" sign in four; all the others had a normal neuroradiological picture. Among the subjects presenting with neurological signs, a subgroup (13 patients) emerged that was characterized by systemic (skin, kidney, liver) involvement. Our data confirm that LCA is a heterogeneous entity that can present as an isolated ocular manifestation, or in association with neurological and systemic abnormalities and support the need for a multidisciplinary approach to this entity and for genotype-phenotype studies.     

Ischemic preconditioning increases the tolerance of Fatty liver to hepatic ischemia-reperfusion injury in the rat

Hepatic steatosis is a major risk factor in ischemia-reperfusion. The present study evaluates whether preconditioning, demonstrated to be effective in normal livers, could also confer protection in the presence of steatosis and investigates the potential underlying protective mechanisms. Fatty rats had increased hepatic injury and decreased survival after 60 minutes of ischemia compared with lean rats. Fatty livers showed a degree of neutrophil accumulation and microcirculatory alterations similar to that of normal livers. However, in presence of steatosis, an increased lipid peroxidation that could be reduced with glutathione-ester pretreatment was observed after hepatic reperfusion. Ischemic preconditioning reduced hepatic injury and increased animal survival. Both in normal and fatty livers, this endogenous protective mechanism was found to control lipid peroxidation, hepatic microcirculation failure, and neutrophil accumulation, reducing the subsequent hepatic injury. These beneficial effects could be mediated by nitric oxide, because the inhibition of nitric oxide synthesis and nitric oxide donor pretreatment abolished and simulated, respectively, the benefits of preconditioning. Thus, ischemic preconditioning could be an effective surgical strategy to reduce the hepatic ischemia-reperfusion injury in normal and fatty livers under normothermic conditions, including hepatic resections, and liver transplantation.     

Sickle cell disease in Sicily.

The chemical and physical properties of haemoglobin S derived from homozygotes for this haemoglobin in Sicily were examined, as well as some erythrocytic characteristics. Sicilian Hb S was identical to that found in USA black patients in electrophoretic mobility on both starch and citrate agar media, solubility, mechanical precipitation rate of oxyhaemoglobins, and minimum gelling concentration, as well as by peptide mapping and amino-acid analysis of all beta-chain peptides. Taken together with the presence in Sicily of African blood group markers and certain historical considerations, it seems clear that the source of Hb S in Sicily is Africa. While the clinical severity in nine Sicilian children did not seem remarkably different from the disease in the USA, the most severe and fatal complications were not seen. Mean Hb F Was 10.5% and 2,3-diphosphoglycerate (2,3-DPG) values were higher in Sicilian homozygotes than in black USA counterparts (21.79 mumol/g Hb vs 15.16). Red cell AT values were also slightly higher in Sicilian patients. The presence of concomitant thalassaemia was excluded by both family studies and globin chain synthetic ratios. In conclusion, haemoglobin S in Sicilian homozygotes is identical to Hb S found in USA blacks. Although the severity of the disease seems quite similar in both groups of patients, other erythrocytic properties were found to be different. Whether these factors influence severity remains to be elucidated.     

Molybdate repair of molybdopterin deficient mutants from Chlamydomonas reinhardtii

Summary The phenotypically wild strain I₃ of Chlamydomonas reinhardtii, carrying a cryptic mutation at the nit-6 locus, was distinguished from strains 21gr (cryptic mutant at nit-5) and 6145c (wild type) because of the ability of I₃ to grow on nitrate media containing 2mM tungstate.Molybdopterin-cofactor (MoCo) mutants 102 (double mutant at nit-5 and nit-6) and 104 (mutant at nit-4) grew on nitrate media supplemented with high concentrations of molybdate, although final cell densities were 40–60% lower and generation times 3.5 to six fold longer than for wild type. Under these conditions, nitrate reductase (NR) activity of the mutants, when measured either in situ or in vitro, was practically undetectable. The MoCo defective mutant 307 (nit-3) was not molybdate repairable. Although NR activity was not restored in vitro by molybdate in any of the MoCo^– mutant strains, their extracts had free NR-diaphorase subunits together with NR-subunits assembled into high molecular weight species.Our results indicate that: a) nit-4, nit-5 and nit-6 loci are responsible for molybdate processing in the cell; b) nit-3 may encode a component of the pterin moiety biosynthetic route; c) NR subunits can assemble in the presence of an inactive MoCo; d) high concentrations of molybdate can replace partially in vivo but not in vitro the function of nit-4 and the combined function(s) of the nit-5 and nit-6 gene products.     

Interleukin-10 haplotypes in Celiac Disease in the Spanish population

Background  

Celiac disease (CD) is a chronic disorder characterized by a pathological inflammatory response after exposure to gluten in genetically susceptible individuals. The HLA complex accounts for less than half of the genetic component of the disease, and additional genes must be implicated. Interleukin-10 (IL-10) is an important regulator of mucosal immunity, and several reports have described alterations of IL-10 levels in celiac patients. The IL-10 gene is located on chromosome 1, and its promoter carries several single nucleotide polymorphisms (SNPs) and microsatellites which have been associated to production levels. Our aim was to study the role of those polymorphisms in susceptibility to CD in our population.     

A standard dosimetry procedure for 192Ir sources used for endovascular brachytherapy

The experimental dosimetry of a high dose rate (HDR) 192Ir source used for the brachytherapy of peripheral vessels is reported. The direct determination of the reference air kerma rate Kr agrees, within the experimental uncertainty, with the results obtained by a well ionization chamber calibrated at the NIST and the manufacturer's certification. A highly sensitive (HS) radiochromic film (RCF), that presents only one active layer, was used for the source dosimetry in a water phantom. The adopted experimental set-up, with the source in its catheter positioned on the RCF plane, seems to have given better accuracy of the RCF optical density measurements. The agreement between the measurement of the dose rate constant DKr (10 mm, pi/2) and the literature data confirmed the coherence of the HS RCF calibration obtained by the kerma in air measurements. The RCF measurements supplied dosimetric information about the dose to water per reference air kerma rate D(r, theta)/Kr along the source transverse bisector axis, the radial dose function g(r) and the anisotropy function F(r, theta). The value D(2 mm, pi/2)/Kr = 22.4 +/- 1.2 cGy h(-1)/(microGy h(-1)) is supplied with a dose uncertainty that is essentially due to the indeterminacy of the source position in the catheter. The data of the radial and anisotropy functions have been compared with Monte Carlo determinations reported in the literature.     

Loss of the O4 antigen moiety from the lipopolysaccharide of an extraintestinal isolate of Escherichia coli has only minor effects on serum sensitivity and virulence in vivo.

The O-specific antigen in extraintestinal isolates of Escherichia coli is believed to be an important virulence factor. To assess its role in the pathogenic process, proven isogenic derivatives with either a complete (CP921) or nearly complete (CP920) deficiency of the O4 antigen were obtained by TnphoA'1-mediated transposon mutagenesis of an O4/K54/H5 blood isolate (CP9). By utilizing a previously reported isogenic K54 capsule-deficient derivative (CP9.137), additional isogenic derivatives deficient in both the K54 capsular antigen and either all (CP923) or nearly all (CP922) of the O4 antigen were also constructed. These strains and their wild-type parent were evaluated in vitro for serum sensitivity and in vivo by intraperitoneal challenge of outbred mice. The complete or nearly complete loss of the O4 antigen (CP920 and CP921) resulted in only a minor increase in serum sensitivity. In contrast, CP9.137 had a significant increase in serum sensitivity, and CP922 and CP923 were extremely serum sensitive. When tested in vivo, the complete or nearly complete loss of the O4 antigen resulted in a small but significant increase (P < or = 0.05), not the expected decrease, in virulence compared with its wild-type parent. In contrast, CP9.137 and CP922 were significantly less virulent (P < or = 0.05). These studies do not exclude a role for the O4 antigen moiety of lipopolysaccharide in the pathogenesis of extraintestinal E. coli infection; however, they demonstrate that the O4 antigen plays only a minor role in serum resistance in vitro and that its loss does not diminish and perhaps enhances the virulence of CP9 in vivo after intraperitoneal challenge.