Radiosensitization of human melanoma cells by ribozyme-mediated inhibition of survivin expression

Survivin is a structurally unique member of the inhibitors of apoptosis protein family and is involved in the control of cell division and inhibition of apoptosis. The notion that survivin is overexpressed in most human tumors but absent in normal adult tissues with only a few exceptions has led to the proposal of survivin as a promising therapeutic target for novel anticancer therapies. In this context, we generated a hammerhead ribozyme targeting the 3' end of the CUA110 triplet in the survivin mRNA. Two human melanoma cell lines (JR8 and M14) overexpressing survivin were stably transfected with the pRc/CMV vector carrying the ribozyme sequence. Two polyclonal cell populations proven to endogenously express ribozyme and characterized by a markedly lower survivin protein level (-60% and -50%, respectively) than JR8 and M14 parental cells were selected for the study. Ribozyme-expressing cells showed a significantly (p<0.01) increased sensitivity to gamma-irradiation (as detected by clonogenic cell survival) compared to JR8 and M14 cells. Moreover, in the JR8 cell line, the extent of radiation-induced apoptosis (in terms of percentage of apoptotic nuclei in cells stained with propidium iodide and level of caspase-3 catalytic activity) was markedly greater in ribozyme-expressing cells than in parental cells. These results demonstrate for the first time that attenuation of survivin expression renders human melanoma cells more susceptible to gamma-irradiation.     

p38 MAP kinase mediates the cell death induced by PrP106-126 in the SH-SY5Y neuroblastoma cells

Prion diseases are neurodegenerative pathologies characterized by the accumulation in the brain of a protease-resistant form of the prion protein (PrP(c)), named PrP(Sc). A synthetic peptide homologous to residues 106-126 of PrP (PrP106-126) maintains many PrP(Sc) characteristics. We investigated the intracellular signaling responsible for the PrP106-126-dependent cell death of SH-SY5Y, a cell line derived from a human neuroblastoma. In this cell line, PrP106-126 induced apoptotic cell death and caused activation of caspase-3, although the blockade of this enzyme did not inhibit cell death. The p38 MAP kinase blockers, SB203580 and PD169316, prevented the apoptotic cell death evoked by PrP106-126 and Western blot analysis revealed that the exposure of the cells to the peptide induced p38 phosphorylation. Taken together, our data suggest that the p38 MAP kinase pathway can mediate the SH-SY5Y cell death induced by PrP106-126.     

The sleep inertia phenomenon during the sleep-wake transition: theoretical and operational issues

Sleep inertia (SI) defines a period of transitory hypovigilance, confusion, disorientation of behavior and impaired cognitive and sensory-motor performance that immediately follows awakening. SI, the cognitive and behavioral correlate of the transition from sleep to wakefulness, has been incorporated in several models of sleep and vigilance regulation. Monitoring of several physiological parameters during the awakening period clearly indicate that this transition process is very slow. On the cognitive and behavioral side, SI has relevant operational implications. SI is one of the most serious contraindications to the use of napping during quasi-continuous operations if the individual may be required to perform complex tasks immediately after sudden awakening at unpredictable times. The studies on SI modulating factors showed that SI is strongly affected by slow wave sleep amount and sleep depth, while the outcomes concerning the modulation of SI by circadian factors are not consistent. Cognitive tasks involving high attentional load seem to be much more affected by SI than simple motor ones, performance accuracy being more impaired than speed. Finally, some possible countermeasures against the detrimental effects of SI to be applied in operational settings have been provided.     

Oculomotor impairment after 1 night of total sleep deprivation: a dissociation between measures of speed and accuracy.

OBJECTIVES: The present study examined the effects of 40 h of sleep deprivation and of time-of-day on saccadic and smooth pursuit oculomotor performance. METHODS: Nine normal subjects slept for 3 consecutive nights in the laboratory (one adaptation, one baseline, one recovery). Baseline and recovery were separated by a period of 40 h of continuous wakefulness, during which subjects were tested every 2 h. Oculomotor performance assessed at the following hours: 10:00, 12:00, 14:00, 16:00, 18:00, 20:00, 22:00, of both the days preceding and following the sleep deprivation night, as well as at 24:00, 02:00, 04:00, 06:00 and 08:00 h during the deprivation period. RESULTS: Saccade latency increased and peak velocity decreased significantly during the post-deprivation day; saccadic accuracy was unaffected. As regards smooth pursuit performance, phase (a measure of accuracy) was not affected by sleep loss, while velocity gain significantly decreased during the day that followed the sleep deprivation night. Significant time-of-day effects on the considered oculomotor variables except saccadic accuracy were also found, indicating an overall performance impairment during the night. CONCLUSIONS: It is concluded that 40 h of sleep deprivation significantly impaired diurnal performance in pursuit and saccadic tasks. This performance worsening is limited to the measures of speed, while accuracy is not affected by sleep loss. A significant operational relevance of these results is suggested, since saccadic velocity has recently been found to be negatively correlated with simulator vehicle crash rates.     

在耐药性局灶性癫痫患者术前评估中采用一种快速可靠的方法定位硬膜下电极

目的：对在耐药性局灶性癫痫患者的术前评估中采用一种新方法定位硬膜下电极进行评估。方法：本研究纳入8例连续患者，患者均为大脑后部癫痫，并且在其硬膜下植入电极用于术前评估。电极植入后，通过基于MATLAB方法的半自动程序，对患者进行脑部CT扫描以检查电极情况。然后将CT扫描与电极植入前的MRI检查相融合，以确定电极与电极下皮质结构间的关系。通过比较电极的3DMRI和术中数码摄像确定的电极位置，测定该方法的可靠性。结果：每例患者的电极均能够正确地定位，并且在立体空间定位上比较直观，这使术者可以制订最佳的手术计划。根据两位独立的评估者的评估结果，3DMRI和术中数码拍摄图像之间的一致性较好，二者间的平均错配值为2mm。结论：尽管本研究结果尚需要在更大样本（包括脑前部癫痫患者）中得以确认，但是上述方法可以定位硬膜下电极，并且可以建立电极（位于脑室、基底节和中部皮质上）与电极下脑组织（正常或受损脑组织）之间的空间关系。意义：由于该方法简单、快速、费用低以及可靠性强，使其有助于医师制订最佳的手术方案。     

Prevalence of hypercontractility in male and female infants with vesico-ureteral reflux.

PURPOSE: To establish whether infants with vesico-ureteral reflux (VUR) have bladder dysfunction, with difference in gender, age at presentation and severity. PATIENTS AND METHODS: 37 infants (24 male and 13 female) aged 2 to 24 months with II degrees to V degrees degree VUR underwent cystometry. Of those, 10 underwent natural filling cystometry. We considered: instability and maximal voiding detrusor pressure (VDP) to be "high" when it exceeded 90 cm H2O. We defined hypercontractility as high VDP and/or instability. RESULTS: The prevalence of hypercontractility was 75% (18/24) in male and 46% (6/13) in female infants (p<0.004). High VDP was found in 50% (12/24) of male and 7% (1/13) of female patients (p < 0.001); no significant difference was found between male (25%) and female ones (38%) with instability alone.The mean VDP was significantly higher in male than in female infants (p < 0.001), in patients < 1 year of age than in older ones (p<0.001) and in severe than in moderate reflux (p<0.006). The mean voiding detrusor pressure of male infants was higher in severe (108+/-46cm H2O) and bilateral (101.3+/-44cm H2O) than in moderate (76+/-24 cm H2O) and unilateral (73.7+/-24 cm H2O) and in infants < 1 year of age (101.7+/-42 cm H2O) than in older ones (70.2+/-21 cm H2O). Natural filling cystometry confirmed the results of standard urodynamic studies. CONCLUSIONS: Bladder dysfunction is confirmed also in infants with reflux, particularly in male younger patients, and it differs in gender. The pathogenesis of congenital reflux is not always a feature of malformation of the vesico-ureteral junction; therefore, patients with bladder dysfunction must be identified early.