Effective implementation of the Accelerate Pheno™ system for positive blood cultures.

Using conventional methods, organism identification (ID) and antibiotic susceptibility testing (AST) results are available ∼1.5-3 days after positive blood culture. New technologies can reduce this time to 8-12 h, allowing therapy to be optimized substantially sooner. To make full use of fast ID and AST results requires overcoming various hurdles to effective implementation, including restructuring laboratory workflows to optimize timeliness of results and modifying clinical pathways to respond more quickly when results are available. Efficient laboratory procedures and clinical interventions coupled with fast and accurate identification and AST results have the potential to substantially reduce overall costs and provide more-sophisticated and effective patient management.

Further evidence of reliability and validity of the Huntington's disease quality of life battery for carers: Italian and French translations.

BACKGROUND: Existing research suggests that family caregivers of persons with Huntington's disease (HD) face a distinct series of problems, linked to the complex nature of the disease. Aubeeluck and Buchanan (Clin Genet, 71(5):434-445, 2007) developed and validated a disease-specific measure used to explore caregivers quality of life and assess the efficacy of therapeutic interventions. This current study builds on this research through the validation of French and Italian translations of the Huntington's disease quality of life battery for carers (HDQoL-C). METHOD: A total of 301 family carers completed the HDQoL-C. Participants were recruited through the "Euro-HDB" study which is measuring the burden in HD across Europe and the USA. RESULTS: Factor analysis demonstrated good internal consistency, reliability and congruent validity. Carers who cared for patients with less clinically severe symptoms reported significantly better QoL than carers of patients with more clinically severe symptoms. DISCUSSION: Findings indicate the HDQoL-C is multi-lingual, multi-cultural and easily applicable in other languages.

Validation of the first quality-of-life measurement for patients with Huntington's disease: the Huntington Quality of Life Instrument.

Health-related quality-of-life instruments are critical for assessing disease burdens. Generic tools allow comparison between diseases but do not discriminate between disease severities. Specific tools also tend to be more sensitive. No specific tool is available to assess quality of life in patients with Huntington's disease (HD). In the context of the European study on HD burden, a specific tool was created: the Huntington Quality of Life Instrument (H-QoL-I). The aim of this study was to optimize the content and validate the H-QoL-I. After a semistructured interview with patients, caregivers and HD specialists, we conducted a patient focus group. A self-reported questionnaire was then developed in French and Italian. A total of 252 patients were recruited to answer the questionnaire. Face, internal and external validities were examined using a variety of methods. The shortened H-QoL-I that resulted from the successive analyses comprises 11 items, which are divided into three dimensions: motor functioning (four items), psychology (four items) and socializing (three items). These three domains were identified as being essential to cover the full domain of the quality of life for patients affected by HD. The H-QoL-I showed an acceptable reliability (Cronbach's α>0.84). Factor analyses demonstrated satisfactory construct validity. Moreover, the item internal consistency and item discriminant validity criteria were fulfilled. No differential item functioning was detected. External validity supported the scale's robustness. These data support the validity of the H-QoL-I in patients with HD.

Riluzole protects Huntington disease patients from brain glucose hypometabolism and grey matter volume loss and increases production of neurotrophins.

PURPOSE: Huntington disease (HD) mutation increases gain-of-toxic functions contributing to glutamate-mediated excitotoxicity. Riluzole interferes with glutamatergic neurotransmission, thereby reducing excitotoxicity, enhancing neurite formation in damaged motoneurons and increasing serum concentrations of BDNF, a brain cortex neurotrophin protecting striatal neurons from degeneration. METHODS: We investigated metabolic and volumetric differences in distinct brain areas between 11 riluzole-treated and 12 placebo-treated patients by MRI and (18)F-fluoro-2-deoxy-D-glucose (FDG) PET scanning, according to fully automated protocols. We also investigated the influence of riluzole on peripheral growth factor blood levels. RESULTS: Placebo-treated patients showed significantly greater proportional volume loss of grey matter and decrease in metabolic FDG uptake than patients treated with riluzole in all cortical areas (p<0.05). The decreased rate of metabolic FDG uptake correlated with worsening clinical scores in placebo-treated patients, compared to those who were treated with riluzole. The progressive decrease in metabolic FDG uptake observed in the frontal, parietal and occipital cortex correlated linearly with the severity of motor scores calculated by Unified Huntington Disease Rating Scale (UHDRS-I) in placebo-treated patients. Similarly, the rate of metabolic changes in the frontal and temporal areas of the brain cortex correlated linearly with worsening behavioural scores calculated by UHDRS-III in the placebo-treated patients. Finally, BDNF and transforming growth factor beta-1 serum levels were significantly higher in patients treated with riluzole. CONCLUSION: The linear correlation between decreased metabolic FDG uptake and worsening clinical scores in the placebo-treated patients suggests that FDG-PET may be a valuable procedure to assess brain markers of HD.

DNA instability in replicating Huntington's disease lymphoblasts.

BACKGROUND: The expanded CAG repeat in the Huntington's disease (HD) gene may display tissue-specific variability (e.g. triplet mosaicism) in repeat length, the longest mutations involving mitotic (germ and glial cells) and postmitotic (neurons) cells. What contributes to the triplet mutability underlying the development of HD nevertheless remains unknown. We investigated whether, besides the increased DNA instability documented in postmitotic neurons, possible environmental and genetic mechanisms, related to cell replication, may concur to determine CAG repeat mutability. To test this hypothesis we used, as a model, cultured HD patients' lymphoblasts with various CAG repeat lengths. RESULTS: Although most lymphoblastoid cell lines (88%) showed little or no repeat instability even after six or more months culture, in lymphoblasts with large expansion repeats beyond 60 CAG repeats the mutation size and triplet mosaicism always increased during replication, implying that the repeat mutability for highly expanded mutations may quantitatively depend on the triplet expansion size. None of the investigated genetic factors, potentially acting in cis to the mutation, significantly influence the repeat changes. Finally, in our experiments certain drugs controlled triplet expansion in two prone-to-expand HD cell lines carrying large CAG mutations. CONCLUSION: Our data support quantitative evidence that the inherited CAG length of expanded alleles has a major influence on somatic repeat variation. The longest triplet expansions show wide somatic variations and may offer a mechanistic model to study triplet drug-controlled instability and genetic factors influencing it.

Distinct brain volume changes correlating with clinical stage, disease progression rate, mutation size, and age at onset prediction as early biomarkers of brain atrophy in Huntington's disease.

Searching brain and peripheral biomarkers is a requisite to cure Huntington's disease (HD). To search for markers indicating the rate of brain neurodegenerative changes in the various disease stages, we quantified changes in brain atrophy in subjects with HD. We analyzed the cross-sectional and longitudinal rate of brain atrophy, quantitatively measured by fully-automated multiparametric magnetic resonance imaging, as fractional gray matter (GM, determining brain cortex volume), white matter (WM, measuring the volume of axonal fibers), and corresponding cerebral spinal fluid (CSF, a measure of global brain atrophy), in 94 gene-positive subjects with presymptomatic to advanced HD, and age-matched healthy controls. Each of the three brain compartments we studied (WM, GM, and CSF) had a diverse role and their time courses differed in the development of HD. GM volume decreased early in life. Its decrease was associated with decreased serum brain-derived-neurotrophic-factor and started even many years before onset symptoms, then decreased slowly in a nonlinear manner during the various symptomatic HD stages. WM volume loss also began in the presymptomatic stage of HD a few years before manifest symptoms appear, rapidly decreasing near to the zone-of-onset. Finally, the CSF volume increase began many years before age at onset. Its volume measured in presymptomatic subjects contributed to improve the CAG-based model of age at onset prediction. The progressive CSF increase depended on CAG mutation size and continued linearly until the last stages of HD, perhaps representing the best marker of progression rate and severity in HD (R(2)= 0.25, P < 0.0001).

Huntington disease in subjects from an Israeli Karaite community carrying alleles of intermediate and expanded CAG repeats in the HTT gene: Huntington disease or phenocopy?

We report a cluster of patients from a Karaite Jew community with a movement disorder suggestive of Huntington disease (HD), in some cases associated with repeat lengths below the edge of 36 CAG repeats. The study describes the clinical and genetic features of four patients who were followed over several years. Patients belonged to an inbred family in whom progressive chorea, manifesting predominantly with dystonia and cerebellar features, developed during middle age. Although severe psychiatric symptoms ultimately developed in two of the four patients, cognitive function remained reasonably well preserved in all of them even after several disease years. Moderate cognitive deficits were limited to the visuomotor organization and abstract thinking subtests in three of the four patients. Qualitative brain imaging showed atrophy of brain predominantly involving cortex and cerebellum. Genetic testing revealed a variable mutation penetrance among family members, some affected members showing an upper allele size ranging from 34 to 49, whereas others remained unaffected despite the presence of the full mutation beyond 40 CAG repeats. Co-morbidity with recessive hereditary inclusion body myopathy was found in two subjects from one family. Although the main diagnosis of HD remains to be confirmed by further neuropathological studies, these cases may suggest that HD could manifest with as few as 34 CAG repeats, in some geographic areas, the disease phenotype most probably being influenced by additional, as yet unidentified, genes.

De novo seven extra repeat expanded mutation in the PRNP gene in an Italian patient with early onset dementia.

Point and octapeptide repeat (24 bp) insertional mutations in the prion protein gene (PRNP) cause a dominantly transmitted dementia, associated with spongiform degeneration of the brain, astrocytic gliosis and neuronal loss due to cell accumulation of mutated protease resistant prion protein. The octapeptide repeat region lies between codon 51 and 91, and comprises a nonapeptide followed by a tandem repeat containing four copies of an octapeptide. The normal tandem length in healthy individuals is five repeats R1-R2-R2-R3-R4, but mutations can contain up to nine additional extra repeats. Some insight into this genetic mechanism comes from the de novo meiotic insertional extra repeat mutation in PRNP we detected in a patient whose parents had a normal phenotype and a wild-type sequence in the same gene. To our knowledge, this is the first time this condition has been described.

Affinity purification of IgG monoclonal antibodies using the D-PAM synthetic ligand: chromatographic comparison with protein A and thermodynamic investigation of the D-PAM/IgG interaction.

This study investigates the applicability of D-PAM, the inverso form of the Protein A Mimetic synthetic peptide affinity ligand (PAM) obtained from the screening of a multimeric combinatorial peptide library, in monoclonal IgG isolation from ascitic fluids and cellular supernatants. D-PAM affinity columns, prepared by immobilizing the all-D peptide on the commercially available support Emphaze, were able to capture monoclonal antibodies in a single chromatographic step, with a recovery yield and purity degree above 90% and full recovery of antibody activity. D-PAM/Emphaze resin showed a host cell protein (HCP) and DNA reduction similar to protein A sorbent. Indeed, column capacity, determined by applying a large excess of purified antibodies to 1 mL of column bed volume, was always higher than 50 mg/mL. D-PAM/IgG interaction was characterized by isothermal titration calorimetry (ITC) and an analysis of binding isotherms, obtained for titration of ST2146, ST1485 and 7H3 IgG monoclonal antibodies, suggested that two peptides bind simultaneously to the IgG molecule, with a K(A) (equilibrium association constant) of 3.4, 6.2 and 3.4 x 10(4) M(-1), and a DeltaH (change in enthalpy) of -1.3, -4.2 and -4.1 kcal mol(-1), respectively.

Highly variable penetrance in subjects affected with cavernous cerebral angiomas (CCM) carrying novel CCM1 and CCM2 mutations.

Cavernous vascular malformations may affect brain and out-of-brain tissues. In most cases, cerebral cavernous malformations (CCMs) involve the brain alone, and are rarely associated with skin hemangiomas, spinal cord, retinal, hepatic or vertebral lesions. CCMs can cause seizures, intracranial and spinal haemorrhages, focal neurological deficits, and migraine-like headaches. After collecting CCM families of Italian origin and investigating the genetic basis of the disorder we disclosed two novel molecular variations in the KRIT1 and MGC4607 genes. We found a novel CCM1 gene mutation (Q66X) in a family with apparently asymptomatic old-aged mutation carriers and patients who either had skin angiomas alone or the full association of cerebral, spinal, and skin lesions. In this family we report the highest variability in mutation penetrance so far described, including the presence of CCM in one subject since birth (surgery at 19 months of age), a condition to our knowledge so far unreported. In a CCM2 affected family, we also report a novel causative mutation, (54_55delAC) in exon 2 of the MGC4607 gene, that produces a truncated protein containing only 22 amino acids. These data describe novel CCM mutations associated with a particularly high variability of the penetrance causing, in some cases, reduced expression of clinical symptoms and sporadic cases with apparent negative family history. Hence they emphasize the importance of DNA-based diagnostics and genetic counseling to identify unaffected mutation carriers subjects, even at advanced age.

Identification and refinement of a peptide affinity ligand with unique specificity for a monoclonal anti-tenascin-C antibody by screening of a phage display library.

Using phage display technology, a 22-mer peptide was selected as a ligand with unique specificity for the murine monoclonal ST2146 antibody that recognizes the EGF repeats region of the human tumor-associated antigen tenascin-C. This peptide, synthesized in an 8-branched form to enhance its binding properties, is useful in replacing the native antigen in the affinity and immunoreactivity characterization of the ST2146 antibody and its biotinylated derivatives. Affinity resins, prepared by immobilizing the mimotope or its shorter 10-mer binding unit on a chromatographic support, were able to capture ST2146 directly from the hybridoma supernatant, with antibody recovery and host cell protein (HCP) reduction similar to or better than protein A sorbent, a purity degree exceeding 95%, and full recovery of antibody activity. The affinity constants of both peptides, as determined by frontal analysis of broad-zone elution affinity chromatography and BiaCore measurements, were very similar and included in a range suitable for affinity ligands. Column capacity, determined by applying a large excess of purified ST2146 to 1 mL of column bed volume, was close to 50 mg/mL for both resins. These matrices retain their ST2146 binding properties after various treatments, including sanitization, thus indicating very high stability in terms of ligand leakage and degradation. Moreover, the short form shows higher enzymatic stability, thus proving more suitable as ligand for ST2146 affinity purification.

The platelet maximum number of A2A-receptor binding sites (Bmax) linearly correlates with age at onset and CAG repeat expansion in Huntington's disease patients with predominant chorea.

Huntington's disease (HD) is caused by an expanded CAG mutation and may show a heterogeneous clinical presentation. To date, although the age at onset mostly depends on the expanded CAG repeat number, no validated easy-to-test biomarkers exist either for following up patients progression rate or for exactly predicting age at onset (defined as the time when motor clinical manifestations first became noticeable). We tested the function of A(2A) receptor, strongly expressed in the brain striatum and peripheral cells, in patients' blood platelets and confirmed a maximum number of binding sites (B(max)) higher than in controls (216 +/- 9 versus 137 +/- 7; p=0.0001). We found a linear correlation between the receptor B(max) and the expanded CAG repeat number (n=52, r(2)=0.19, p=0.0011). When we selected the patients according to their clinical presentation (according to the predominating motor manifestations) and plotted the receptor B(max) against patients' age at onset, we found a significant linear correlation only when considering those subjects with chorea predominant on all other motor symptoms (n=26, r(2)=0.39, p=0.0007). Because the typical chorea may depend on early dysfunction of the striatum in HD, peripheral A(2A) amplification in blood platelets might reflect a central dysfunction in this part of the brain. Further studies on a larger sample size should confirm whether the analysis of A(2A)-receptor binding in patients' blood could be a useful clinical marker according to the patients' phenotype.

New Huntington disease mutation arising from a paternal CAG34 allele showing somatic length variation in serially passaged lymphoblasts.

The analysis of somatic CAG triplet variation in lymphoblastoid cell lines from subjects carrying alleles of intermediate length (IA(33CAG) and IA(34CAG)) in Huntington disease (HD) gene disclosed instability in the DNA of the person, from whom a new expansion mutation of 45 triplets originated. The triplet size increased after about 30 passages in cell cultures in lymphoblasts with the IA(34) genotype. Lymphoblasts may provide an appropriate model for studying repeat instability in subjects with poly(CAG) repeat disorders. HD shows somatic, in addition to germ-line instability, highlighting the propensity to somatic CAG variation in human cells even with repeat numbers under the expanded edge. Factors potentially cis acting with the mutation, other than those reported in this study (CCG polymorphic stretch, the deletion of the glutamic acid residue at position 2642 and the 4-codon segment between CAG and CCG polymorphisms), should be searched for and analyzed.