Biomechanical and clinical study of single posterior oblique cage POLIF in the treatment of degenerative diseases of the lumbar spine

Introduction

Aim of the study was to evaluate the biomechanical stability and the clinical efficacy of a lumbar interbody fusion obtained by single oblique cage implanted by a posterior approach.

Method

Through the realization of three finite element models (FEMs), the biomechanics of POLIF was compared to PLIF and TLIF. Ninety-four patients underwent interbody fusion by POLIF with instrumented posterolateral fusion. Clinical and radiographic outcomes were evaluated at regular intervals for at least 6 months.

Results

The FEMs showed no statistically significant differences in stability in compression and flexion–extension. Mean preoperative VAS score was 7.1, decreased to 2.1 at follow-up. Mean preoperative SF-12 value was 34.5 %, increased to 75.4 % at follow-up. All patients showed a good fusion rate and no hardware failure.

Discussion

POLIF associated to instrumented posterolateral fusion is a viable and safe surgical technique, which ensures a biomechanical stability similar to other surgical techniques.

     

Cold denaturation and 2H2O stabilization of a staphylococcal nuclease mutant.

Cold denaturation is now recognized as a general property of proteins but has been observed only under destabilizing conditions, such as moderate denaturant concentration or low pH. By destabilizing the protein using site-directed mutagenesis, we have observed cold denaturation at pH 7.0 in the absence of denaturants in a mutant of staphylococcal nuclease, which we call NCA S28G for a hybrid protein between staphylococcal nuclease and concanavalin A in which there is the point mutation Ser-28----Gly. The temperature of maximum stability (tmax) as determined by circular dichroism (CD) was 18.1 degrees C, and the midpoints of the thermal unfolding transitions (tm) were 0.6 degrees C and 30.0 degrees C. These values may be compared with the tm of 52.5 degrees C for wild-type staphylococcal nuclease, for which no cold denaturation was observed under these conditions. When the stability of the mutant was examined in 2H2O by NMR, CD, or fluorescence, a substantial increase in the amount of folded protein at the tmax was noted as well as a decrease in tmax, reflecting increased stability.     

Ebola viral load at diagnosis associates with patient outcome and outbreak evolution

BACKGROUND. Ebola virus (EBOV) causes periodic outbreaks of life-threatening EBOV disease in Africa. Historically, these outbreaks have been relatively small and geographically contained; however, the magnitude of the EBOV outbreak that began in 2014 in West Africa has been unprecedented. The aim of this study was to describe the viral kinetics of EBOV during this outbreak and identify factors that contribute to outbreak progression.METHODS. From July to December 2014, one laboratory in Sierra Leone processed over 2,700 patient samples for EBOV detection by quantitative PCR (qPCR). Viremia was measured following patient admission. Age, sex, and approximate time of symptom onset were also recorded for each patient. The data was analyzed using various mathematical models to find trends of potential interest.RESULTS. The analysis revealed a significant difference (P = 2.7 × 10^–77) between the initial viremia of survivors (4.02 log₁₀ genome equivalents [GEQ]/ml) and nonsurvivors (6.18 log₁₀ GEQ/ml). At the population level, patient viral loads were higher on average in July than in November, even when accounting for outcome and time since onset of symptoms. This decrease in viral loads temporally correlated with an increase in circulating EBOV-specific IgG antibodies among individuals who were suspected of being infected but shown to be negative for the virus by PCR.CONCLUSIONS. Our results indicate that initial viremia is associated with outcome of the individual and outbreak duration; therefore, care must be taken in planning clinical trials and interventions. Additional research in virus adaptation and the impacts of host factors on EBOV transmission and pathogenesis is needed.     

Evaluation of Pyrosequencing for Detecting Extensively Drug-Resistant Mycobacterium tuberculosis among Clinical Isolates from Four High-Burden Countries

Reliable molecular diagnostics, which detect specific mutations associated with drug resistance, are promising technologies for the rapid identification and monitoring of drug resistance in Mycobacterium tuberculosis isolates. Pyrosequencing (PSQ) has the ability to detect mutations associated with first- and second-line anti-tuberculosis (TB) drugs, with the additional advantage of being rapidly adaptable for the identification of new mutations. The aim of this project was to evaluate the performance of PSQ in predicting phenotypic drug resistance in multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB) clinical isolates from India, South Africa, Moldova, and the Philippines. A total of 187 archived isolates were run through a PSQ assay in order to identify M. tuberculosis (via the IS6110 marker), and to detect mutations associated with M/XDR-TB within small stretches of nucleotides in selected loci. The molecular targets included katG, the inhA promoter and the ahpC-oxyR intergenic region for isoniazid (INH) resistance; the rpoB core region for rifampin (RIF) resistance; gyrA for fluoroquinolone (FQ) resistance; and rrs for amikacin (AMK), capreomycin (CAP), and kanamycin (KAN) resistance. PSQ data were compared to phenotypic mycobacterial growth indicator tube (MGIT) 960 drug susceptibility testing results for performance analysis. The PSQ assay illustrated good sensitivity for the detection of resistance to INH (94%), RIF (96%), FQ (93%), AMK (84%), CAP (88%), and KAN (68%). The specificities of the assay were 96% for INH, 100% for RIF, FQ, AMK, and KAN, and 97% for CAP. PSQ is a highly efficient diagnostic tool that reveals specific nucleotide changes associated with resistance to the first- and second-line anti-TB drug medications. This methodology has the potential to be linked to mutation-specific clinical interpretation algorithms for rapid treatment decisions.     

Post-recurrence survival in hepatocellular carcinoma after percutaneous radiofrequency ablation

Background

Overall survival in hepatocellular carcinoma patients treated with percutaneous radiofrequency ablation is influenced by both recurrence and successive treatments. We investigated post-recurrence survival after radiofrequency ablation.

Methods

Data on 103 early/intermediate patients initially treated with radiofrequency ablation and followed for a median of 78 months (range 68–82) were retrospectively analysed. If intrahepatic disease recurrence occurred within or contiguous to the previously treated area it was defined as local, otherwise as distant; recurrence classified as Barcelona Clinic Liver Cancer stage C was defined by neoplastic portal vein thrombosis or metastases.

Results

A total of 103 patients were included (82.5% male; median age 70 years, range 39–86). During follow-up, 64 recurrences were observed. Median overall survival was 62 months (95% confidence interval: 54–78) and survival rates were 97%, 65% and 52% at 1, 4 and 5 years, respectively. Median post-recurrence survival was 22 months (95% confidence interval: 16–35). Child–Pugh score, performance status, sum of tumour diameters at recurrence and recurrence patterns were independent predictors of post-recurrence survival.

Conclusions

In patients with hepatocellular carcinoma after radiofrequency ablation, clinical and tumour parameters assessed at relapse, in particular the type of recurrence pattern, influence post-recurrence survival.     

IsdC from Staphylococcus lugdunensis Induces Biofilm Formation under Low-Iron Growth Conditions

Staphylococcus lugdunensis is a coagulase-negative staphylococcus that is a commensal of humans and an opportunistic pathogen. It can cause a spectrum of infections, including those that are associated with the ability to form biofilm, such as occurs with endocarditis or indwelling medical devices. The genome sequences of two strains revealed the presence of orthologues of the ica genes that are responsible for synthesis of poly-N-acetylglucosamine (PNAG) that is commonly associated with biofilm in other staphylococci. However, we discovered that biofilm formed by a panel of S. lugdunensis isolates growing in iron-restricted medium was susceptible to degradation by proteases and not by metaperiodate, suggesting that the biofilm matrix comprised proteins and not PNAG. When the iron concentration was raised to 1 mM biofilm formation by all strains tested was greatly reduced. A mutant of strain N920143 lacking the entire locus that encodes iron-regulated surface determinant (Isd) proteins was defective in biofilm formation under iron-limited conditions. An IsdC-null mutant was defective, whereas IsdK, IsdJ, and IsdB mutants formed biofilm to the same level as the parental strain. Expression of IsdC was required both for the primary attachment to unconditioned polystyrene and for the accumulation phase of biofilm involving cell-cell interactions. Purified recombinant IsdC protein formed dimers in solution and Lactococcus lactis cells expressing only IsdC adhered to immobilized recombinant IsdC but not to IsdJ, IsdK, or IsdB. This is consistent with a specific homophilic interaction between IsdC molecules on neighboring cells contributing to accumulation of S. lugdunensis biofilm in vivo.     

Molecular events underlying interleukin‐6 independence in a subclone of the CMA‐03 multiple myeloma cell line

We explored the molecular mechanisms involved in the establishement of CMA‐03/06, an IL‐6‐independent variant of the multiple myeloma cell line CMA‐03 previously generated in our Institution. CMA‐03/06 cells grow in the absence of IL‐6 with a doubling time comparable with that of CMA‐03 cells; neither the addition of IL6 (IL‐6) to the culture medium nor co‐culture with multipotent mesenchymal stromal cells increases the proliferation rate, although they maintain the responsiveness to IL‐6 stimulation as demonstrated by STAT1, STAT3, and STAT5 induction. IL‐6 independence of CMA‐03/06 cells is not apparently due to the development of an autocrine IL‐6 loop, nor to the observed moderate constitutive activation of STAT5 and STAT3, since STAT3 silencing does not affect cell viability or proliferation. When compared to the parental cell line, CMA‐03/06 cells showed an activated pattern of the NF‐κB pathway. This finding is supported by gene expression profiling (GEP) analysis identifying an appreciable fraction of modulated genes (28/308) in the CMA‐03/06 subclone reported to be involved in this pathway. Furthermore, although more resistant to apoptotic stimuli compared to the parental cell line, CMA‐03/06 cells display a higher sensibility to NF‐κB inhibition induced by bortezomib. Finally, GEP analysis suggests an involvement of a number of cytokines, which might contribute to IL‐6 independence of CMA‐03/06 by stimulating growth and antiapoptotic processes. In conclusion, the parental cell‐line CMA‐03 and its variant CMA‐03/06 represent a suitable model to further investigate molecular mechanisms involved in the IL‐6‐independent growth of myeloma cells. © 2013 Wiley Periodicals, Inc.