Psychometric properties of the Quality of Life Inventory-Disability (QI-Disability) measure

Quality of Life Research - Children with intellectual disability encounter daily challenges beyond those captured in current quality of life measures. This study evaluated a new parent-report...     

Role of 16-multidetector computed tomography in the assessment of coronary artery stenoses: A prospective study of consecutive patients

BACKGROUND: Recent studies have demonstrated a high sensitivity (S) of 16-multidetector computed tomography (16-MDCT) for the detection of significant coronary artery stenoses. Whether these results are applicable to clinical practice is unclear. Therefore, the aim of the present study was to compare 16-MDCT angiography with conventional coronary angiography (CCA) for the detection of significant coronary artery stenoses in a consecutive series of patients. METHOD: A total of 93 consecutive patients (mean [+/- SD] age 59+/-9 years), in whom CCA was performed for stable angina pectoris, underwent 16-MDCT angiography (16x0.75 mm, table feed 6.5 mm/s, rotation time 0.42 s; Sensation 16, Siemens Medical Solutions, Germany) the day before performing CCA. Patients with diabetes mellitus, serum creatinine level higher than 132.6 mumol/L and/or acute coronary syndromes were excluded. Two observers blinded to CCA results evaluated MDCT angiograms according to standard criteria. Segment-based (13 segments per patient) and patient-based (at least one stenosis greater than 50% lumen diameter reduction) analyses were performed. RESULTS: A total of 1209 segments were analyzed. Of these segments, 173 (14%) were excluded due to poor image quality or massive calcification. In 86 segments, CCA revealed significant coronary artery stenosis (greater than 50% diameter reduction). However, 16-MDCT detected only 47 of these, resulting in a S of 55% and a specificity (SP) of 97% (positive predictive value 64%; negative predictive value 96%). On a patient-based analysis, the S increased to 89%, whereas the SP still remained high (87%). CONCLUSION: In this relatively large consecutive cohort, S for the detection of significant coronary artery stenoses was moderate on a segment-based analysis but increased on a patient-based analysis using 16-MDCT. In contrast, SP was high in both analyses, supporting the use of 16-MDCT for the exclusion of significant coronary artery stenoses. Further improvement of spatial and temporal resolution in MDCT technology may lead to a lower exclusion rate and higher S.     

Mechanical properties of achilles tendon in rats induced to experimental diabetes

The aim of this study was to quantify the effect of chemically induced diabetes mellitus (DM) on the mechanical properties of the Achilles tendon of rats and correlate it with metabolic and biomechanical findings. Adult rats were selected randomly and assigned to two groups, the diabetic group consisted of animals receiving a dose of streptozotocin to induce type I diabetes and the control group. The animals were placed in metabolic cages for analysis of metabolism. Ten weeks after diabetes induction, the Achilles tendon of both groups were collected and submitted to a traction test in a conventional testing machine. The measurements of mechanical properties indicated that the elastic modulus (MPa) was significantly higher in the control group (p < 0.01). In Maximum tension (MPa), the groups did not have differences (p > 0.01). Energy/tendon area (N mm/mm²), specific strain (%) and maximum specific strain (mm) were higher in tendon tests of the diabetic group (p < 0.01). We observed that the mechanical properties of tendons have correlations with metabolic properties of the diabetic animals. These results showed that induced DM in rats have an important negative effect on the mechanical properties of the Achilles tendon.     

Rapid and Accurate Diagnosis of Human Intestinal Spirochetosis by Fluorescence In Situ Hybridization

Human intestinal spirochetosis (HIS) is associated with overgrowth of the large intestine by spirochetes of the genus Brachyspira. The microbiological diagnosis of HIS is hampered by the fastidious nature and slow growth of Brachyspira spp. In clinical practice, HIS is diagnosed histopathologically, and a significant portion of cases may be missed. Fluorescence in situ hybridization (FISH) is a molecular method that allows the visualization and identification of single bacteria within tissue sections. In this study, we analyzed intestinal biopsy samples from five patients with possible HIS. All specimens yielded positive results by histopathological techniques. PCR amplification and sequencing of the 16S rRNA gene were performed. Sequences of two isolates clustered in the group of Brachyspira aalborgi, whereas in three cases, the sequences were highly similar to that of Brachyspira pilosicoli. Three phylotypes showed mismatches at distinct nucleotide positions with Brachyspira sp. sequences published previously. In addition, culture for Brachyspira was successful in three cases. On the basis of these data, we designed and evaluated a Brachyspira genus-specific 16S rRNA-directed FISH probe that detects all of the Brachyspira spp. published to date. FISH of biopsy samples resulted in strong, unequivocal signals of brush-like formations at the crypt surfaces. This technique allowed simultaneous visualization of single spirochetes and their identification as Brachyspira spp. In conclusion, FISH provides a fast and accurate technique for the visualization and identification of intestinal spirochetes in tissue sections. It therefore represents a valuable tool for routine diagnosis of HIS.Human intestinal spirochetosis (HIS) is a histologically defined condition of the human distal intestinal tract characterized by helical microorganisms attached at one end to the surface epithelium of the colonic mucosa. This association forms a so-called “false brush border” (13). While certain Brachyspira spp. are recognized as the causative agents of swine dysentery and porcine intestinal spirochetosis (3, 11), their clinical significance and pathogenic potential for humans remain unclear. Various studies have reported on the association of these bacteria with intestinal disorders such as chronic watery diarrhea (8, 12) and on clinical improvement following antimicrobial therapy (29). In contrast, others have suggested that intestinal spirochetes are harmless commensals in humans (7). The prevalence of HIS ranges from 1.2% (23) to >40% (17, 34), depending on presumable patient risk factors, such as origin from developing countries, immunodeficiency, or homosexuality. Recently, Peruzzi et al. (30) discovered a prevalence of 12% in a selected population, indicating that HIS is an important differential diagnosis for patients with chronic gastrointestinal disorders and risk factors.Two intestinal spirochetes have been identified in humans so far: Brachyspira aalborgi (15) and Brachyspira pilosicoli (36). Both species require selective media, and B. aalborgi is an extremely slow growing, fastidious microorganism that requires anaerobic incubation for as long as 4 weeks (4, 34). For this reason, HIS is primarily diagnosed histopathologically. The fuzzy basophilic fringe, 4 to 7 μm thick, on the epithelial layer of the colonic mucosa is visible in hematoxylin-and-eosin (HE)-stained histological sections and is considered pathognomonic for HIS. Tissue morphology usually remains unaltered, and no inflammatory reaction is observed (20).However, diagnosis of HIS on the basis of HE staining requires experienced laboratory personnel and accurate interpretation, and silver staining is often needed to confirm the diagnosis (10). Therefore, a significant portion of cases may be missed, especially since B. pilosicoli might also colonize the epithelium without the characteristic end-on attachment, impeding identification by light microscopy at low magnification (24). Furthermore, histopathology does not provide information about the identity of the microorganisms, thereby precluding epidemiological studies. More importantly, the inability to identify the organism also hampers accurate therapy, since the intestinal spirochetes are suspected to differ in virulence, and therefore some cases of HIS may require antibiotic therapy more urgently than others (5, 29).The genus Brachyspira currently comprises seven established species and several proposed species. Among some Brachyspira species, the high level of 16S rRNA gene conservation precludes interspecies differentiation by 16S rRNA gene methods and necessitates further molecular analyses. However, all known species isolated from humans can be identified and differentiated via their 16S rRNA genes. In line with the genetic variation discovered in Brachyspira species, such as Brachyspira hyodysenteriae (2) and Brachyspira innocens (9), recent molecular studies have also identified human Brachyspira strains genetically distinct from B. aalborgi and B. pilosicoli. This heterogeneity was confirmed by sequencing of 16S rRNA (14, 21) or NADH oxidase (25) genes, fluorescence in situ hybridization (FISH) (16, 17), or multilocus enzyme electrophoresis (33). Pettersson et al. (31) analyzed biopsy samples from two adults by 16S rRNA gene sequencing and consequently proposed to divide the B. aalborgi lineage into three phylogenetic clusters, including the type strain, B. aalborgi 513A, in the first cluster.The extent of intraspecies genetic variation in human intestinal spirochetes is unclear and difficult to estimate, because few complete 16S rRNA gene sequences are available. Further epidemiologic and phylogenetic investigations are needed to elucidate spirochete genetic diversity and to facilitate the evaluation of the molecular diagnostic tools that are presently available.FISH is a microscopic method that allows simultaneous visualization and identification of microorganisms. Jensen and colleagues (3, 16, 17) designed several genus- or species-specific oligonucleotide probes targeting the 16S or 23S rRNA of Brachyspira spp. and applied them successfully to porcine and human intestinal biopsy specimens. However, no genus-specific 16S rRNA-directed probe for diagnostic use targeting all Brachyspira spp. known so far has been developed.In the present study, intestinal biopsy specimens from five patients with possible HIS were analyzed histopathologically and by culture, FISH, PCR amplification, and 16S rRNA gene sequencing. Biopsy specimens from a healthy control group were analyzed retrospectively by histopathology and FISH. The purpose was (i) to acquire further information about the phylogenetic structure of the Brachyspira spp. associated with HIS, (ii) to design a FISH probe covering all Brachyspira spp. based on the currently available sequence data, and (iii) to evaluate FISH as a fast and robust diagnostic screening tool for HIS.     

Hand hygiene technique

Hand hygiene is an essential component of effective infection prevention programmes. Good technique, ensuring that all surfaces of the hands receive contact with the decontaminating agent, has been accepted for many years and is acknowledged in current guidelines. However, hand hygiene technique is seldom incorporated into research studies and audits designed to increase compliance. As a result, numerous unanswered questions remain concerning this aspect of hand hygiene.     

p42/44 MAPK is an essential effector for purine nucleoside-mediated neuroprotection of hypoxic PC12 cells and primary cerebellar granule neurons

Purine nucleosides protect neurons against hypoxic insult, but the signaling mechanisms have not yet been fully elucidated. We studied the role of the p42/44 MAPK pathway in purine nucleoside-mediated protection of cultured PC12 cells and primary cerebellar granule neurons from hypoxia-induced cell death. Incubation with adenosine reduced hypoxia-evoked cell death morphology, and increased the activity of the MAPK pathway. Inosine, a metabolic derivative of adenosine was generally less potent in PC12 cells. Pharmacological inhibition of the MAPK pathways severely hampered adenosine-mediated induction of cell viability and neurite outgrowth. Consistently, siRNA-mediated knockdown of p42 and p44 MAPK completely blocked adenosine-mediated rescue of hypoxic PC12 cells. The role of MAPK activation was further studied in primary neurons. Cells were significantly rescued by adenosine and inosine and siRNA-mediated knockdown severely affected purine-mediated rescue of neuronal viability after hypoxic insult. Results point to the important role of p42/44 MAPK for adenosine receptor-mediated neuroprotection.     

Enhanced long-term potentiation and impaired learning in phosphodiesterase 4D-knockout (PDE4D) mice

Elevation of intracellular cyclic adenosine monophosphate (cAMP) concentrations and subsequent regulation of downstream target gene expression through phosphorylation of cAMP-responsive element binding protein (CREB) is hypothesized to underlie the mechanism(s) of long-term memory (LTM) formation. The phosphodiesterase 4 (PDE4) enzyme family is believed to play a key role in LTM by regulating cAMP levels. Thus far, four PDE4 isoforms have been identified ( PDE4A , B , C and D ); however, the requisite involvement of each of these isoforms in mediating LTM has yet to be elucidated. In the present study, genetic knockout mice were used to investigate the involvement of the PDE4D isoform in both in vitro and in vivo models of learning and memory. Hippocampal synaptic transmission measured electrophysiologically in CA1 slice preparations was similar between wild-type and PDE4D ^−/− mice yet, relative to wild-type controls, knockout mice displayed enhanced early long-term potentiation (LTP) following multiple induction protocols. Interestingly, the PDE4D ^−/− animals exhibited significant behavioral deficits in associative learning using a conditioned fear paradigm as compared with control littermates. The impairment in fear conditioning observed in the PDE4D ^−/− mice could not be attributed to differences in acquisition of the task, alterations in locomotor activity or effects on shock sensitivity. Overall, the in vitro and in vivo alterations in synaptic plasticity observed in the PDE4D ^−/− mice may be explained by adaptive responses occurring throughout development, and suggest that the PDE4D isoform may be an important mediator of LTM formation.     

Determination of the prognostic value of loss of heterozygosity at the retinoblastoma gene in osteosarcoma

The retinoblastoma (RB) tumour suppressor gene is implicated in the development of several malignancies including osteosarcoma. Recent studies postulated its loss of heterozygosity (LOH) to be a poor prognostic factor at diagnosis of osteosarcoma (OS). It remains unclear whether LOH of the RB gene is suitable as a prognostic factor at diagnosis in patients with osteosarcoma. In this study we aimed to determine the early prognostic value of RB-LOH as well as the ability of denaturating high performance liquid chromatography (DHPLC) to detect LOH at this gene locus in comparison to classical PAGE. We therefore analysed 41 samples of OS on restriction fragment length polymorphisms in introns 1, 17 and 25, and variable numbers of tandem repeats (VNTRs) in intron 20. PCR fragments were separated on 1.5% agarose gel electrophoresis. VNTRs with length differentiation of only a few base pairs were analysed by 8% PAA/Spreadex gels and additionally by DHPLC. One-hundred percent concordance was observed between the results obtained by classical PAGE and DHPLC. The latter improved intron 20 analysis as a sensitive and high throughput method for detecting LOH. Overall we found 16 RB-LOH in 41 OS (39%). Three tumours exhibited additional microsatellite instability. There was no significant correlation of the event-free- and overall-survival rate or response to chemotherapy with RB-LOH found in our study. LOH positivity was associated with a significantly younger age at diagnosis. In conclusion RB-LOH could not be verified as a poor prognostic factor for osteosarcoma in the present study.     

Transketolase protein TKTL1 overexpression: A potential biomarker and therapeutic target in breast cancer

Malignant tumors degrade glucose to lactate even in the presence of oxygen via the pentose phosphate pathway (ppp). The non-oxidative part of the ppp is controlled by thiamine-dependant transketolase enzyme reactions. Overexpression of the transketolase-like-1-gene (TKTL1) in urothelial and colorectal cancer is associated with poor patient outcome. We analyzed the expression of the TKTL1 protein in a retrospective institution-based patient cohort with invasive breast cancer by immunohistochemical analysis of 124 paraffin-embedded breast cancer tissues. Our study revealed TKTL1 expression in 86% of breast cancer specimens with 45% showing high expression levels. In contrast, only 29% of corresponding non-neoplastic breast tissues were TKTL1 immunopositive, including 9% with high expression levels. High expression levels of TKTL1 correlated significantly to Her2/neu overexpression (p=0.015). However, TKTL1 expression failed to reach statistical significance for other common prognostic parameters. In contrast to recent data for e.g. colorectal cancer TKTL1 overexpression did not correlate to patient outcome and survival. However, in the context of novel insights into TKTL1-related tumor metabolism and the high proportion of TKTL1 overexpressing breast cancers, this enzyme represents a potential candidate for targeted inhibition of tumor growth in this tumor entity.