Nanocomposites of hydroxyapatite with aspartic acid and glutamic acid and their interaction with osteoblast-like cells

The direct synthesis of hydroxyapatite (HA)-aspartic acid (ASP) and HA-glutamic acid (GLU) nanocrystals was carried out in presence of different amounts of the amino acids in solution. ASP and GLU incorporation into HA crystals reduces the coherent length of the perfect crystalline domains along the long dimension (002) and, even more, along the cross section (310) of the apatite crystals, suggesting a specific interaction of the amino acids with the HA structure. FTIR analysis indicates that the carboxylic groups of the acidic amino acids interact with the calcium ions of HA. The relative amount of ASP incorporation into HA nanocrystals is greater than that of GLU, suggesting a greater affinity of ASP for HA. Osteoblast-like, MG63, cells cultured on the composite nanocrystals display good proliferation and increased values of ALP activity, collagen type I, TGF-betaI and osteocalcin production, indicating that the presence of the acidic amino acids enhances osteoblast activation and extra-cellular matrix mineralization processes.     

Evaluation of the new VITEK 2 extended-spectrum beta-lactamase (ESBL) test for rapid detection of ESBL production in Enterobacteriaceae isolates

Extended-spectrum beta-lactamases (ESBLs) are a large, rapidly evolving group of enzymes that confer resistance to oxyimino cephalosporins and monobactams and are inhibited by clavulanate. Rapid reliable detection of ESBL production is a prerequisite for successful infection management and for monitoring resistance trends and implementation of intervention strategies. We evaluated the performance of the new VITEK 2 ESBL test system (bioMérieux, Inc, Hazelwood, Mo.) in the identification of ESBL-producing Enterobacteriaceae isolates. We examined a total of 1,129 clinically relevant Enterobacteriaceae isolates (including 218 that had been previously characterized). The ESBL classification furnished by the VITEK 2 ESBL test system was concordant with that of the comparison method (molecular identification of beta-lactamase genes) for 1,121 (99.3%) of the 1,129 isolates evaluated. ESBL production was correctly detected in 306 of the 312 ESBL-producing organisms (sensitivity, 98.1%; positive predictive value, 99.3%). False-positive results emerged for 2 of the 817 ESBL-negative isolates (specificity, 99.7%; negative predictive value, 99.3%). VITEK 2 ESBL testing took 6 to 13 h (median, 7.5 h; mean +/- SD, 8.2 +/- 2.39 h). This automated short-incubation system appears to be a rapid and reliable tool for routine identification of ESBL-producing isolates of Enterobacteriaceae.     

Elevated serum 8-oxo-dG in hemodialysis patients: a marker of systemic inflammation?

Does inflammation, as assessed by high sensitivity C-reactive protein (hs-CRP), in patients with end-stage renal disease (ESRD) tightly associate with increased serum levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8- oxo-dG)? Increased oxidative stress and inflammation have both been highlighted among several nontraditional risk factors for cardiovascular disease, which is the main cause of mortality in ESRD patients. In contrast to oxidative stress effects on proteins and lipids, DNA base damage has not been well demonstrated in ESRD. Two groups of hemodialysis patients were studied, one group with persistent inflammation (n = 13, with constant elevation of CRP > 10 mg/L for 6 months) and one group of noninflamed patients (n = 19, with constant CRP < 10 mg/L for 6 months). Serum 8-oxo-dG was significantly elevated in persistent inflammation in comparison to noninflamed patients. At an individual level, a significant correlation was found between serum 8-oxo-dG and hsCRP. Extracellular 8-oxo-dG leads to intracellular oxidative damage on the nucleotide pool, thus providing a sensitive marker for inflammatory response. Serum levels of 8-oxo-dG, in combination with other inflammatory markers, serve as useful diagnostic tools for identification of patients in risk for inflammatory complications.     

Do asthma and allergy influence subsequent pet keeping? An analysis of childhood and adulthood

BACKGROUND: Asthma and allergy might influence the choice of keeping pets, leading to apparent protective effects of pets on allergic disease. OBJECTIVE: We investigated the effects of asthma and allergy on subsequent pet keeping in childhood and adulthood. METHODS: Information about asthma and pet keeping at ages 0 to 4, 5 to 15, 20 to 44, and 26 to 56 years was provided by 9812 subjects participating in the 9-year follow-up of the European Community Respiratory Health Survey. RESULTS: In childhood asthma debut at younger than 5 years was associated with less cat keeping at 5 to 15 years (odds ratio [OR], 0.60; 95% CI, 0.44-0.82), an effect only observed when the parents did not have asthma or allergy (P(interaction) = .045). Childhood asthma did not influence adult pet ownership, unless there were adult symptoms. Adults less often acquired cats at follow-up if they had 3 or more asthma symptoms (OR, 0.78; 95% CI, 0.64-0.95), were taking asthma medication (OR, 0.48; 95% CI, 0.31-0.74), had hay fever (OR, 0.75; 95% CI, 0.62-0.91), had atopy (OR, 0.75; 95% CI, 0.61-0.91), or had specific IgE to cat (OR, 0.57; 95% CI, 0.39-0.82) at baseline. Adults who already had pets usually continued keeping the same type of pet, except that the presence of 3 or more asthma symptoms was associated with less subsequent dog keeping (OR, 0.69; 95% CI, 0.53-0.89). Pet removal between surveys to reduce allergen was reported by 4.7%. CONCLUSION: Selective avoidance subsequent to asthma or allergy was observed for childhood cat keeping and adult cat acquisition. Avoidance would produce an apparent protective effect of cats on childhood asthma (large OR, 0.83). Avoidance was generally not observed for dogs or birds. CLINICAL IMPLICATIONS: A part of the protective effects of childhood cats on asthma and allergy can be attributed to selective avoidance.     

Multicenter comparison of PCR assays for detection of human herpesvirus 6 DNA in serum

Human herpesvirus 6 (HHV-6) is a ubiquitous virus with which infections have been associated with pathologies ranging from delayed bone marrow engraftment to a variety of neurological diseases. The lack of a standardized assay that can be used to detect and estimate HHV-6 DNA contents in various clinical specimens can lead and has led to discordant results among investigators and on the potential association of HHV-6 to diseases. To identify the most reliable and sensitive assays, an identical set of 11 coded serum samples spiked with various quantities of the HHV-6A variant (range, 4 to 400,000 genome copies/ml) was sent to eight independent laboratories around the world. Each laboratory was asked to estimate the HHV-6 DNA content by use of its own protocols and assays. Among the various assays, three TaqMan-based real-time PCR assays yielded quantities that were closest to the quantity of HHV-6 that had been spiked. To provide better homogeneity between the results from the different laboratories working on HHV-6, we propose that investigators interested in quantifying HHV-6 in clinical samples adopt one of these assays.     

Identification of the smallest structure capable of evoking opsonophagocytic antibodies against Streptococcus pneumoniae type 14

Synthetic overlapping oligosaccharide fragments of Streptococcus pneumoniae serotype 14 capsular polysaccharide (Pn14PS), [6)-[beta-D-Galp-(1-->4)-]beta-D-GlcpNAc-(1-->3)-beta-D-Galp-(1-->4)-beta-D-Glcp-(1-->](n), were conjugated to CRM(197) protein and injected into mice to determine the smallest immunogenic structure. The resulting antibodies were then tested for Pn14PS specificity and for their capacity to promote the phagocytosis of S. pneumoniae type 14 bacteria. Earlier studies have reported that the oligosaccharide corresponding to one structural repeating unit of Pn14PS, i.e., Gal-Glc-(Gal-)GlcNAc, induces a specific antibody response to Pn14PS. The broader study described here, which evaluated 16 oligosaccharides, showed that the branched trisaccharide element Glc-(Gal-)GlcNAc is essential in inducing Pn14PS-specific antibodies and that the neighboring galactose unit at the nonreducing end contributes clearly to the immunogenicity of the epitope. Only the oligosaccharide conjugates that produce antibodies recognizing Pn14PS were capable of promoting the phagocytosis of S. pneumoniae type 14. In conclusion, the branched tetrasaccharide Gal-Glc-(Gal-)GlcNAc may be a serious candidate for a synthetic oligosaccharide conjugate vaccine against infections caused by S. pneumoniae type 14.     

Characterization of the null murine sodium/myo-inositol cotransporter 1 (Smit1 or Slc5a3) phenotype: myo-inositol rescue is independent of expression of its cognate mitochondrial ribosomal protein subunit 6 (Mrps6) gene and of phosphatidylinositol levels in neonatal brain

Ablation of the murine Slc5a3 gene results in severe myo-inositol (Ins) deficiency and congenital central apnea due to abnormal respiratory rhythmogenesis. The lethal knockout phenotype may be rescued by supplementing the maternal drinking water with 1% Ins. In order to test the hypothesis that Ins deficiency leads to inositide deficiencies, which are corrected by prenatal treatment, we measured the effects of Ins rescue on Ins, phosphatidylinositol (PtdIns) and myo-inositol polyphosphate levels in brains of E18.5 knockout fetuses. As the Slc5a3 gene structure is unique in the sodium/solute cotransporter (SLC5) family, and exon 1 is shared with the mitochondrial ribosomal protein subunit 6 (Mrps6) gene, we also sought to determine whether expression of its cognate Mrps6 gene is abnormal in knockout fetuses. The mean level of Ins was increased by 92% in brains of rescued Slc5a3 knockout fetuses (0.48 versus 0.25 nmol/mg), but was still greatly reduced in comparison to wildtype (6.97 nmol/mg). The PtdIns, InsP(5) and InsP(6) levels were normal without treatment. Mrps6 gene expression was unaffected in the E18.5 knockout fetuses. This enigmatic model is not associated with neonatal PtdIns deficiency and rescue of the phenotype may be accomplished without restoration of Ins. The biochemical mechanism that both uniformly leads to death and allows for Ins rescue remains unknown. In conclusion, in neonatal brain tissue, Mrps6 gene expression may not be contingent on function of its embedded Slc5a3 gene, while inositide deficiency may not be the mechanism of lethal apnea in null Slc5a3 mice.     

HIV-1 diversity among inmates of Italian prisons

In Italy, the prevalence of non-B HIV-1 subtypes ranges reportedly from 5.4% to 12.6%, yet there are no data on their circulation in prisons, where the prevalence of HIV infection is high. A retrospective study was conducted to evaluate the circulation of non-B subtypes and to characterize their determinants in five Italian prisons. To this end an aliquot of samples of blood was taken in the period 2001-2006 from all 262 HIV-positive inmates in whom antiretroviral treatment had failed. Complete HIV-1 PR and RT regions were sequenced for all samples and subjected to phylogenetic analysis; 250 (95.4%) sequences clustered with subtype B. The non-B subtype was found in 4% of Italian prison inmates and 16.7% of non-Italian prison inmates; the overall percentage increased from 1.8% for inmates infected in 1982-1990 to 4.4% in 1991-1999 and 21.9% in 2000-2006. Factors significantly associated with non-B subtypes were an exposure to other than injecting drug use and a first positive HIV test in 2000-2006. Non-B subtypes were distributed within five monophyletic clades. In all cases but one, it was possible to correlate the history of HIV-exposure to the origin of the clade, with high bootstrap values. In conclusion, although the sample may not be representative of the prison inmate population in Italy, the data suggest strongly that the circulation of non-B subtypes has apparently increased. Non-B subtypes were found to have been associated with heterosexual contact and time of the first HIV-positive test. Knowledge of the different subtypes circulating in prisons may be useful for tracking the epidemiology of HIV infection and for choosing antiretroviral therapy.