Low level of the mtDNA deletion in blood of exceptionally old individuals

The common 4977-bp deletion in mitochondrial DNA (dmtDNA⁴⁹⁷⁷) occurs frequently in tissues of high oxygen demand and low mitotic activity, e.g. brain, heart and skeletal muscle, where it appears to show an age-related accumulation. Although dmtDNA⁴⁹⁷⁷ can also be detected in very low amounts in fast replicating tissues such as blood, it is still unclear whether an age-dependent distribution of dmtDNA⁴⁹⁷⁷ occurs in blood. In view of these uncertainties, we investigated the presence of the mutation and changes in the dmtDNA⁴⁹⁷⁷ level in whole blood samples from 473 individuals who belong to two different age groups, i.e. elderly (aged 61-75 years) and long-lived individuals (LLI, aged 95-109 years). We applied a highly sensitive and reliable duplex-PCR method that allowed relative quantification of dmtDNA⁴⁹⁷⁷. For validation, we additionally performed absolute quantification on a subset of samples using real time-PCR. Our results showed that the proportion of dmtDNA⁴⁹⁷⁷ carriers was very similar in both groups, but that the individual mutational load was on average much lower in the nonagenarians and centenarians than in the elderly. The finding was independent of smoking habits, gender or variation in APOE and FOXO3A but could be caused by other environmental and/or genetic factors.     

Interfering with resistance to smoothened antagonists by inhibition of the PI3K pathway in medulloblastoma

The malignant brain cancer medulloblastoma is characterized by mutations in Hedgehog (Hh) signaling pathway genes, which lead to constitutive activation of the G protein (heterotrimeric guanosine triphosphate-binding protein)-coupled receptor Smoothened (Smo). The Smo antagonist NVP-LDE225 inhibits Hh signaling and induces tumor regression in animal models of medulloblastoma. However, evidence of resistance was observed during the course of treatment. Molecular analysis of resistant tumors revealed several resistance mechanisms. We noted chromosomal amplification of Gli2, a downstream effector of Hh signaling, and, more rarely, point mutations in Smo that led to reactivated Hh signaling and restored tumor growth. Analysis of pathway gene expression signatures also, unexpectedly, identified up-regulation of phosphatidylinositol 3-kinase (PI3K) signaling in resistant tumors as another potential mechanism of resistance. Probing the relevance of increased PI3K signaling, we demonstrated that addition of the PI3K inhibitor NVP-BKM120 or the dual PI3K-mTOR (mammalian target of rapamycin) inhibitor NVP-BEZ235 to the initial treatment with the Smo antagonist markedly delayed the development of resistance. Our findings may be useful in informing treatment strategies for medulloblastoma.     

Adenovirus vector production and purification

Replication deficient adenovirus vectors are frequently used tools for the delivery of transgenes in vitro and in vivo. In addition, several therapeutic products based on adenovirus are under clinical development. This review outlines adenovirus vector production discussing different vector types, available production cell lines and state of the art of production process development and purification.     

T-cell-specific deletion of STIM1 and STIM2 protects mice from EAE by impairing the effector functions of Th1 and Th17 cells

T-cell function is dependent on store-operated Ca(2+) influx that is activated by the stromal interaction molecules (STIM) 1 and 2. We show that mice with T-cell-specific deletion of STIM1 or STIM2 are protected from EAE, a mouse model of multiple sclerosis (MS). While STIM1- and STIM2-deficient T cells could be successfully primed by autoantigen, they failed to produce the proinflammatory cytokines IL-17 and IFN-γ. STIM1-deficient T cells showed reduced expression of IL-23R, required for Th17 cell homeostasis, and had impaired chemokine-dependent T-cell migration caused by a lack of chemokine-induced Ca(2+) influx. Autoantigen-specific STIM1- or STIM2-deficient T cells failed to expand and accumulate in the CNS and lymph nodes following adoptive transfer to passively induce EAE, suggesting that autoantigen-specific restimulation or homeostasis of STIM1- and STIM2-deficient T cells are impaired. Combined deletion of both STIM1 and STIM2, previously shown to impair Treg development and function, completely protected mice from EAE. This indicates that, in the absence of Ca(2+) influx, autoreactive T cells are severely dysfunctional rendering Treg dispensable for the prevention of CNS inflammation. Our findings demonstrate that both STIM1 and STIM2 are critical for T-cell function and autoimmunity in vivo.     

Deletion mapping in Alport syndrome and Alport syndrome-diffuse leiomyomatosis reveals potential mechanisms of visceral smooth muscle overgrowth

Diffuse leiomyomatosis is associated with the inherited kidney disease Alport syndrome, and characterized by visceral smooth muscle overgrowth within the respiratory, gastrointestinal and female reproductive tracts. Although partial deletions of the type IV collagen genes COL4A5 and COL4A6, paired head-to-head on chromosome Xq22, are known to cause diffuse leiomyomatosis, loss of function for type IV collagen does not explain smooth muscle overgrowth. To further clarify pathogenic mechanisms, we have characterized novel deletions in patients with Alport syndrome-diffuse leiomyomatosis or Alport syndrome alone. A 27.6-kb deletion, in a female with Alport syndrome-diffuse leiomyomatosis, is marked by the most proximal, i.e. most 5', COL4A5 breakpoint described to date. By comparing this deletion to others described here and previously, we have defined a minimal overlap region, only 4.2 kb in length and containing the COL4A5-COL4A6 proximal promoters, loss of which contributes to smooth muscle overgrowth. A novel deletion in a male with Alport syndrome alone is>1.4 Mb in length, encompassing COL4A5 and COL4A6 entirely, as well as neighboring genes. We postulate that loss of the 4.2-kb region in diffuse leiomyomatosis causes misregulation of neighboring genes, contributing to smooth muscle overgrowth. Deletion of the neighboring genes themselves may afford protection from this condition.     

C-KIT expression in ductal carcinoma in situ of the breast: co-expression with HER-2/neu

The proto-oncogene c-KIT (CD117) is highly expressed in normal breast epithelium and is decreased in invasive breast cancer. In this study, we analyzed the protein expression and the mutational status of c-KIT in ductal carcinoma in situ (DCIS) of the breast and correlated these findings with nuclear grade, architectural pattern, and expression of HER-2, estrogen receptor (ER)-alpha, and progesterone receptor (PR). C-KIT, HER-2, ER, and PR expression were analyzed immunohistochemically in 106 cases of paraffin-embedded DCIS (85 pure DCIS and 21 DCIS with concurrent carcinoma). Direct sequencing of exons 9 and 11 of the c-KIT gene was performed to analyze the hot spot mutational regions in representative cases. C-KIT expression was found in 55 (52.8%) of all DCIS, correlating with high nuclear grade (P < .0001), comedonecrosis (P < .0001), and solid growth pattern (P = .001). Furthermore, c-KIT expression was strongly associated with HER-2 positivity (P < .0001) and was significantly lower in ER- or PR-positive cases (P = .001 and P = .006, respectively). C-KIT expression alone or co-expression with HER-2 in pure DCIS did not differ significantly from DCIS with invasive component (P = .09). Mutational analysis in 6 c-KIT-positive DCIS revealed no activating mutations in exons 9 or 11. Our findings suggest that the expression of c-KIT protein might define a subset of poorly differentiated, HER-2-positive DCIS with decreased expression of steroid hormone receptors, comedonecrosis, and a solid growth pattern. The implications of c-KIT and HER-2 co-expression for breast carcinogenesis should be further evaluated.     

Slow continuous ultrafiltration with bound solute dialysis

Bound solute dialysis (BSD), often referred to as "albumin dialysis" (practiced clinically as the molecular adsorbents recirculating system, MARS, or single-pass albumin dialysis, SPAD) or "sorbent dialysis" (practiced clinically as the charcoal-based Biologic-DT), is based upon the thermodynamic principle that the driving force for solute mass transfer across a dialysis membrane is the difference in free solute concentration across the membrane. The clinically relevant practice of slow continuous ultrafiltration (SCUF) for maintenance of patients with liver failure is analyzed in conjunction with BSD. The primary dimensionless operating parameters that describe SCUF-BSD include (1) beta, the dialysate/blood binder concentration ratio; (2) kappa, the dialyzer mass transfer/blood flow rate ratio; (3) alpha, the dialysate/blood flow rate ratio; and, (4) gamma, the ultrafiltration/blood flow rate ratio. Results from mathematical modeling of solute removal during a single pass through a dialyzer and solute removal from a one-compartment model indicate that solute removal is remarkably insensitive to gamma. Solute removal approaches an asymptote (improvement in theoretical clearance over that obtainable with no binder in the dialysate) with increasing beta that is dependent on kappa and independent of alpha. The amount of binder required to approach the asymptote decreases with increasing solute-binder equilibrium constant, i.e., more strongly bound solutes require less binder in the dialysate. The results of experimental observations over a range of blood flow rates, 100 to 180 mL/min, dialysate flow rates, 600 to 2150 mL/h, ultrafiltration rates, 0 to 220 mL/h, and dialysate/blood albumin concentration ratios, beta = 0.01 to 0.04, were independently predicted remarkably well by the one-compartment model (with no adjustable parameters) based on BSD principles.     

Adaptive spatio-temporal filtering of multichannel surface EMG signals

A motor unit (MU) is defined as an anterior horn cell, its axon, and the muscle fibres innervated by the motor neuron. A surface electromyogram (EMG) is a superposition of many different MU action potentials (MUAPs) generated by active MUs. The objectives of this study were to introduce a new adaptive spatio-temporal filter, here called maximum kurtosis filter (MKF), and to compare it with existing filters, on its performance to detect a single MUAP train from multichannel surface EMG signals. The MKF adaptively chooses the filter coefficients by maximising the kurtosis of the output. The proposed method was compared with five commonly used spatial filters, the weighted low-pass differential filter (WLPD) and the marginal distribution of a continuous wavelet transform. The performance was evaluated using simulated EMG signals. In addition, results from a multichannel surface EMG measurement fro from a subject who had been previously exposed to radiation due to cancer were used to demonstrate an application of the method. With five time lags of the MKF, the sensitivity was 98.7% and the highest sensitivity of the traditional filters was 86.8%, which was obtained with the WLPD. The positive predictivities of these filters were 87.4 and 80.4%, respectively. Results from simulations showed that the proposed spatio-temporal filtration technique significantly improved performance as compared with existing filters, and the sensitivity and the positive predictivity increased with an increase in number of time lags in the filter.     

Rapid Subcutaneous IgG Replacement Therapy is Effective and Safe in Children and Adults with Primary Immunodeficiencies—A Prospective, Multi-National Study

Sixty patients (16 children, 44 adults) participated in the study aiming at evaluating: (i) IgG levels when switching patients from intravenous IgG (IVIG) infusions in hospital to subcutaneous (SCIG) self-infusions at home using the same cumulative monthly dose, (ii) protections against infections, and (iii) safety of a new, ready-to-use 16% IgG preparation. All children and 33 adults had received IVIG therapy for >6 months at enrolment. Ten adults who had been on SCIG therapy for many years served as controls. Mean serum IgG trough levels increased in the pre-IVIG children from 7.8 to 9.2 g/L (non-inferiority: p < 0.001) and in the adults from 8.6 to 8.9 g/L (non-inferiority: p < 0.001). Totally 114 respiratory tract infections occurred, 90% of them mild. One serious bacterial infection (pneumonia) was reported for one adult. The annualized rate of serious infections was 0.04 episodes/patient. In total 2297 infusions were given and 28 (1%) systemic adverse reactions occurred, none of them severe. Local tissue reactions declined over time, this being particularly distinct after 8 to 10 weeks. In conclusion, the SCIG administration route was safe. High IgG levels were easily maintained resulting in a very good protection against infections.     

Extreme heterogeneity in CARD15 and DLG5 Crohn disease-associated polymorphisms between German and Norwegian populations

The first gene associated with Crohn disease (CD) has been identified as CARD15 (16q12). Three variants, R702W, G908R and 1007fsinsC are strongly and independently associated with the disease. A second gene, conveying a smaller risk for inflammatory bowel disease (IBD), has been identified as DLG5 (10q23). We assess the frequency of the CARD15 SNPs and of the R30Q mutation in DLG5 and their contribution to the development of CD in a cohort of unrelated IBD patients (151 CD, 325 ulcerative colitis (UC)) and healthy controls (236) from South-east Norway (IBSEN cohort). Genotype-based tests of population differentiation using 23 SNPs across CARD15, together with estimates of F(ST), indicated that the German and Norwegian background populations could be differentiated at the CARD15 locus. The Norwegian and German CD samples exhibited particularly strong differentiation at the three predisposing loci and those marking their background haplotype. There were significantly lower frequencies of the CARD15 SNPs and no significant association with CD in the Norwegian samples. Only a marginal association was observed for the subphenotypes ileitis and ileocolitis vs colitis (P=0.048). The population attributable risk percentage (PAR%) for CARD15 variants in the Norwegian cohort is the lowest reported for a European population (1.88%), except Iceland. Similarly, the DLG5 variant showed no association with CD or IBD, however, there was a negative correlation with stricture (P=0.035). The present results are consistent with an emerging pattern of a low frequency of the CARD15 variants in Northern countries where the prevalence of IBD is greatest.