P-glycoprotein mediates celecoxib-induced apoptosis in multiple drug-resistant cell lines

In several neoplastic diseases, including hepatocellular carcinoma, the expression of P-glycoprotein and cyclooxygenase-2 (COX-2) are often increased and involved in drug resistance and poor prognosis. P-glycoprotein, in addition to drug resistance, blocks cytochrome c release, preventing apoptosis in tumor cells. Because COX-2 induces P-glycoprotein expression, we evaluated the effect of celecoxib, a specific inhibitor of COX-2 activity, on P-glycoprotein-mediated resistance to apoptosis in cell lines expressing multidrug resistant (MDR) phenotype. Experiments were done using MDR-positive and parental cell lines at basal conditions and after exposure to 10 or 50 micromol/L celecoxib. We found that 10 micromol/L celecoxib reduced P-glycoprotein, Bcl-x(L), and Bcl-2 expression, and induced translocation of Bax from cytosol to mitochondria and cytochrome c release into cytosol in MDR-positive hepatocellular carcinoma cells. This causes the activation of caspase-3 and increases the number of cells going into apoptosis. No effect was shown on parental drug-sensitive or on MDR-positive hepatocellular carcinoma cells after transfection with MDR1 small interfering RNA. Interestingly, although inhibiting COX-2 activity, 50 micromol/L celecoxib weakly increased the expression of COX-2 and P-glycoprotein and did not alter Bcl-x(L) and Bcl-2 expression. In conclusion, these results show that relatively low concentrations of celecoxib induce cell apoptosis in MDR cell lines. This effect is mediated by P-glycoprotein and suggests that the efficacy of celecoxib in the treatment of different types of cancer may depend on celecoxib concentration and P-glycoprotein expression.     

Cortical connections of the visuomotor parietooccipital area V6Ad of the macaque monkey

Area V6A, a functionally defined region in the anterior bank of the parietooccipital sulcus, has been subdivided into dorsal and ventral cytoarchitectonic fields (V6Ad and V6Av). The aim of this study was to define the cortical connections of the cytoarchitectonic field V6Ad. Retrograde and bidirectional neuronal tracers were injected into the dorsal part of the anterior bank of parietooccipital sulcus of seven macaque monkeys (Macaca fascicularis). The limits of injection sites were compared with those of cytoarchitectonic fields. The major connections of V6Ad were with areas of the superior parietal lobule. The densest labeling was observed in the medial intraparietal area (MIP). Areas PEc, PGm, and V6Av were also strongly connected. Labeled cells were found in medial parietal area 31; in cingulate area 23; in the anterior (AIP), ventral (VIP), and lateral (LIP) intraparietal areas; in the inferior parietal lobule (fields Opt and PG); and in the medial superior temporal area (MST). In the frontal lobe, the main projection originated from F2, although labeled cells were also found in F7 and area 46. Preliminary results obtained from injections in nearby areas PEc and V6Av revealed connections different from those of V6Ad. In agreement with functional data, the strong connections with areas where arm‐reaching activity is represented suggest that V6Ad is part of a parietofrontal circuit involved in the control of prehension, and connections with AIP specifically support an involvement in the control of grasping. Connections with areas LIP and Opt are likely related to the oculomotor activities observed in V6Ad. J. Comp. Neurol. 513:622–642, 2009. © 2009 Wiley‐Liss, Inc.     

Occult hepatitis B virus infection in liver transplant recipients with recurrent hepatitis C: relationship with donor age and fibrosis progression

Abstract:  Liver transplantation (OLT) recipients who receive a graft from donors positive for hepatitis B virus (HBV) anti-core antibodies may develop overt " de novo " HBV infection. The study was undertaken to explore how often HBV infection may remain occult after OLT for hepatitis C, and whether it may represent a factor of graft fibrosis progression. We studied 30 consecutive patients transplanted for hepatitis C liver disease. Specimens from the native liver and from the graft were searched for occult HBV infection (O-HBV). In the native liver, 8/30 patients had detectable O-HBV; during the follow-up, O-HBV infection was demonstrated in 14 graft specimens. Graft O-HBV was associated with older donor age (≥50 yr; 8/9 vs. 6/21, p < 0.005). Recipients with graft O-HBV and no O-HBV in the native liver who received their grafts from donors aged >40 yr had faster fibrosis progression than recipients with no post-transplant O-HBV, whose grafts came from donors aged >40 yr and recipients whose grafts came from donors aged ≤40 yr (4/7 vs. 1/7 vs. 2/16, p < 0.05). In OLT recipients, O-HBV is more likely to occur when grafts are obtained from aged donors and may affect the rate of fibrosis progression because of recurrent hepatitis C.     

Bleomycin-Based Electrochemotherapy: Clinical Outcome from a Single Institution’s Experience with 52 Patients

Electrochemotherapy (ECT) has emerged as a complementary treatment for superficial metastases. Fifty-two consecutive patients with different cancer histotypes, mainly melanoma and breast cancer, with disease unsuitable for conventional treatments underwent bleomycin-based ECT for cutaneous and subcutaneous metastases. Toxicity, local response, response duration, and the impact on quality of life were evaluated. A total of 608 tumor nodules were treated (mean, 12 per patient), with 27% of patients affected by nodules >3 cm in size. Treatment was tolerated well, especially under general sedation. An objective response was obtained in 50 (96%) of 52 patients 1 month after the first application. Twenty-two patients underwent a second treatment (because of partial response or the appearance of new lesions). Partial response at first ECT achieved a response consolidation at second application: 80% complete response, 20% partial response. Some patients underwent up to five treatments because of new lesions, but maintained superficial tumor control. After a mean follow-up of 9 (range, 2–21) months, only two patients experienced relapse in the treatment field. Through a nonvalidated eight-item questionnaire (assessing wound healing and bleeding, aesthetic impairment, daily activities, social relations, pain, treatment satisfaction, acceptance of retreatment), most patients reported a benefit in local disease-related complaints and in activity of daily living. In a palliative setting, ECT proved to be safe, effective in all tumors treated, and useful in preserving patients’ quality of life. This benefit, although preliminary, deserves further assessment after a formal validation of the dedicated questionnaire.     

A microswitch-cluster program to foster adaptive responses and head control in students with multiple disabilities: replication and validation assessment

A program relying on microswitch clusters (i.e., combinations of microswitches) and preferred stimuli was recently developed to foster adaptive responses and head control in persons with multiple disabilities. In the last version of this program, preferred stimuli (a) are scheduled for adaptive responses occurring in combination with head control (i.e., head upright) and (b) last through the scheduled time only if head control is maintained for that time. The first of the present two studies was aimed at replicating this program with three new participants with multiple disabilities adding to the three reported by Lancioni et al. [Lancioni, G. E., Singh, N. N., O'Reilly, M. F., Sigafoos, J., Didden, R., Oliva, D., et al. (2007). Fostering adaptive responses and head control in students with multiple disabilities through a microswitch-based program: Follow-up assessment and program revision. Research in Developmental Disabilities, 28, 187-196]. The second of the two studies served to carry out an expert validation of the program's effects on head control and general physical condition with the three participants of Study I as well as the three participants involved in the Lancioni et al. study mentioned above. The expert raters were 72 new physiotherapists and 72 experienced physiotherapists. The results of Study I supported previous data and indicated that the program was effective in helping the participants increase the frequency of adaptive responses in combination with head control and the length of such control. The results of Study II showed that the raters found the effects of the new program more positive than those of other intervention conditions and also considered such program a useful complement to formal motor rehabilitation programs.     

Network plasticity in cortical assemblies

To investigate distributed synaptic plasticity at the cell assembly level, we used dissociated cortical networks from embryonic rats grown on grids of 60 extracellular substrate-embedded electrodes (micro-electrode arrays). We developed a set of experimental plasticity protocols based on the pairing of tetanic bursts (20 Hz) with low-frequency stimuli (≤ 1 Hz), delivered through two separate channels of the array (i.e. associative tetanic stimulation). We tested our protocols on a large data set of 26 stable cultures, selected on the basis of both their initial level of spontaneous firing and the capability of low-frequency test stimuli to evoke spikes. Our main results are summarized as follows: (i) low-frequency stimuli produce neither short- nor long-term changes in the evoked response of the network; (ii) associative tetanic stimulation is able to induce plasticity in terms of a significant increase or decrease of the evoked activity in the whole network; (iii) the amount of change (i.e. increase or decrease of the evoked firing) strongly depends on the specific features of the applied protocols; and (iv) the potentiation induced by a specific associative protocol can last several hours. The results obtained demonstrate that large in vitro cortical assemblies display long-term network potentiation, a mechanism considered to be involved in the memory formation at cellular level. This pilot study could represent a relevant step towards understanding plastic properties at the neuronal population level.     

Gentamicin treatment in exercised mdx mice: Identification of dystrophin-sensitive pathways and evaluation of efficacy in work-loaded dystrophic muscle

Aminoglycosides force read through of premature stop codon mutations and introduce new mutation-specific gene-corrective strategies in Duchenne muscular dystrophy. A chronic treatment with gentamicin (32 mg/kg/daily i.p., 8-12 weeks) was performed in exercised mdx mice with the dual aim to clarify the dependence on dystrophin of the functional, biochemical and histological alterations present in dystrophic muscle and to verify the long term efficiency of small molecule gene-corrective strategies in work-loaded dystrophic muscle. The treatment counteracted the exercise-induced impairment of in vivo forelimb strength after 6-8 weeks. We observed an increase in dystrophin expression level in all the fibers, although lower than that observed in normal fibers, and found a concomitant recovery of aquaporin-4 at sarcolemma. A significant reduction in centronucleated fibers, in the area of necrosis and in the percentage of nuclear factor-kB-positive nuclei was observed in gastrocnemious muscle of treated animals. Plasma creatine kinase was reduced by 70%. Ex vivo, gentamicin restored membrane ionic conductance in mdx diaphragm and limb muscle fibers. No effects were observed on the altered calcium homeostasis and sarcolemmal calcium permeability, detected by electrophysiological and microspectrofluorimetric approaches. Thus, the maintenance of a partial level of dystrophin is sufficient to reinforce sarcolemmal stability, reducing leakiness, inflammation and fiber damage, while correction of altered calcium homeostasis needs greater expression of dystrophin or direct interventions on the channels involved.     

Cerebrovascular disease and hippocampal atrophy are differently linked to functional coupling of brain areas: an EEG coherence study in MCI subjects

The working hypothesis of paper is that the functional coupling of brain areas is combined with different neuroradiological substrates and has different clinical manifestations. 31 normal old subjects and 85 subjects with mild cognitive impairment (MCI) underwent EEG recordings and magnetic resonance imaging (MRI). Intrahemispheric and interhemispheric linear EEG coherences were computed. At first, all normal old and MCI subjects were compared. Subsequently, three subgroups of MCI were obtained based on neuroradiological substrate (subcortical cerebrovascular damage, MCI-CVD; cholinergic pathways vascular damage MCI-CHOL; and hippocampal atrophy, MCI-HIPP) and compared with a normal old sample matched for age, education and Mini-Mental State Examination score. The group of MCI subjects compared to normal old subjects shows: 1) decrease of intrahemispheric coherence in fronto-parietal regions (both right and left hemisphere); 2) increase of interhemispheric coherence on frontal regions in delta frequency; and 3) increase of interhemispheric coherence on temporal regions (from delta to alpha3 frequency bands). In the MCI subgroups, hippocampal atrophy is linked to an increase of interhemispheric coherence seen on frontal and temporal regions whereas subcortical CVD is linked to the largest decrease of coherence in fronto-parietal regions. MCI-CVD patients performed worst on Trail Making Test battery whereas MCI-HIPP patients were impaired on Rey word list delayed recall and Rey figure recall.