Nucleophosmin (NPM), an oligomeric phosphoprotein and nucleolar target of the ARF tumor suppressor, contributes to several critical cellular processes. Previous studies have shown that the human ...NPM's phosphorylation by cyclin E-cyclin-dependent kinase 2 (cdk2) on threonine (Thr) 199 regulates its translocation from the centrosome during cell cycle progression. Given our previous finding that ARF directly binds NPM, impeding its transit to the cytoplasm and arresting cells before S-phase entry, we hypothesized that ARF might also inhibit NPM phosphorylation. However, ARF induction did not impair phosphorylation of the cdk2 target residue in murine NPM, Thr198. Furthermore, phosphorylation of Thr198 occurred throughout the cell cycle and was concomitant with increases in overall NPM expression. To investigate the cell's presumed requirement for NPM-Thr198 phosphorylation in promoting the processes of growth and proliferation, we examined the effects of a non-phosphorylatable NPM mutant, T198A, in a clean cell system in which endogenous NPM had been removed by RNA interference. Here, we show that the T198A mutant is fully capable of executing NPM's described roles in nucleocytoplasmic shuttling, ribosome export and cell cycle progression. Moreover, the proliferative defects observed with stable NPM knockdown were restored by mutant NPM-T198A expression. Thus, we demonstrate that the reduction in NPM protein expression blocks cellular growth and proliferation, whereas phosphorylation of NPM-Thr198 is not essential for NPM's capacity to drive cell cycle progression and proliferation.
Although many studies suggest that, on average, depression-specific psychotherapy and antidepressant pharmacotherapy are efficacious, we know relatively little about which patients are more likely to ...respond to one versus the other. We sought to determine whether measures of spectrum psychopathology are useful in deciding which patients with unipolar depression should receive pharmacotherapy versus depression-specific psychotherapy.
A total of 318 adult out-patients with major depression were randomly assigned to escitalopram pharmacotherapy or interpersonal psychotherapy (IPT) at academic medical centers at Pittsburgh, Pennsylvania and Pisa, Italy. Our main focus was on predictors and moderators of time to remission on monotherapy at 12 weeks.
Participants with higher scores on the need for medical reassurance factor of the Panic-Agoraphobic Spectrum Self-Report (PAS-SR) had more rapid remission with IPT and those with lower scores on the psychomotor activation factor of the Mood Spectrum Self-Report (MOODS-SR) experienced more rapid remission with selective serotonin reuptake inhibitor (SSRI) pharmacotherapy. Non-specific predictors of longer time to remission with monotherapy included several panic spectrum and mood spectrum factors and the Social Phobia Spectrum (SHY) total score. Higher baseline scores on the 17- and 25-item Hamilton Depression Rating Scales (HAMD-17 and HAMD-25) and the Work and Social Adjustment Scale (WSAS) also predicted a longer time to remission, whereas being married predicted a shorter time to remission.
This exploratory study identified several non-specific predictors but few moderators of psychotherapy versus pharmacotherapy outcome. It offers useful indicators of the characteristics of patients that are generally difficult to treat, but only limited guidance as to who benefits from IPT versus SSRI pharmacotherapy.
Key points
Loss‐of‐function mutations of the skeletal muscle ClC‐1 channel cause myotonia congenita with variable phenotypes.
Using patch clamp we show that F484L, located in the conducting pore, ...probably induces mild dominant myotonia by right‐shifting the slow gating of ClC‐1 channel, without exerting a dominant‐negative effect on the wild‐type (WT) subunit.
Molecular dynamics simulations suggest that F484L affects the slow gate by increasing the frequency and the stability of H‐bond formation between E232 in helix F and Y578 in helix R.
Three other myotonic ClC‐1 mutations are shown to produce distinct effects on channel function: L198P shifts the slow gate to positive potentials, V640G reduces channel activity, while L628P displays a WT‐like behaviour (electrophysiology data only).
Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC‐1 function.
Myotonia congenita is an inherited disease caused by loss‐of‐function mutations of the skeletal muscle ClC‐1 chloride channel, characterized by impaired muscle relaxation after contraction and stiffness. In the present study, we provided an in‐depth characterization of F484L, a mutation previously identified in dominant myotonia, in order to define the genotype–phenotype correlation, and to elucidate the contribution of this pore residue to the mechanisms of ClC‐1 gating. Patch‐clamp recordings showed that F484L reduced chloride currents at every tested potential and dramatically right‐shifted the voltage dependence of slow gating, thus contributing to the mild clinical phenotype of affected heterozygote carriers. Unlike dominant mutations located at the dimer interface, no dominant‐negative effect was observed when F484L mutant subunits were co‐expressed with wild type. Molecular dynamics simulations further revealed that F484L affected the slow gate by increasing the frequency and stability of the H‐bond formation between the pore residue E232 and the R helix residue Y578. In addition, using patch‐clamp electrophysiology, we characterized three other myotonic ClC‐1 mutations. We proved that the dominant L198P mutation in the channel pore also right‐shifted the voltage dependence of slow gating, recapitulating mild myotonia. The recessive V640G mutant drastically reduced channel function, which probably accounts for myotonia. In contrast, the recessive L628P mutant produced currents very similar to wild type, suggesting that the occurrence of the compound truncating mutation (Q812X) or other muscle‐specific mechanisms accounted for the severe symptoms observed in this family. Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC‐1 function.
Post-menopausal osteoporosis women are at increased risk for skeletal fractures with higher mortality and lower quality of life. Some studies have reported fall risk reduction in the elderly after ...Tai chi practice. Tai chi is a weight bearing mind-body exercise that has been reported to positively influence bone mineral density and improve postural control in different pathologies. The aim of this observational randomized case control study is to evaluate the effect of Tai chi on balance and quality of life in postmenopausal women with osteoporosis. A total of 98 postmenopausal osteoporosis women, aged 70.6±8.2 years (mean and standard deviation), (mean T-score of the hip and spine were-2.9± 0.92 and -2.8±1.08), have been recruited in outpatients University Physical Medicine and Rehabilitation Hospital between June 2016 and September 2018. They have been randomized to a Tai group (56 patients, mean age 71.61±7.97 years) practiced 6-month Tai chi program, two times week, plus standard care or to a Control Group (42 patients, mean age 69.71±8.61 years) practiced usual care. Patients with oncological, neurological, cognitive, vestibular and visual diseases were excluded. Patients were evaluated at baseline (T0), prior Tai chi and after 6 month (T1) with 36-Item Short Form Health Survey (SF-36), and a stabilometric-standardized exam performed for the evaluation, respectively, of the quality of life and the static balance. The groups were homogenous at baseline. T1 evaluation showed better results in Tai chi group, in SF36 Physical functioning (p level: 0.021), Physical health pain (p level: 0.020), Physical composite score (p level: 0.003) scores, compared with control group. There were not significant differences between groups in stabilometric analysis. Tai chi group showed significant better stabilometric values at T1 compared with T0 in mean anterior-posterior (p level: 0.001) and medio-lateral (p level: 0.019) velocity, in perimeter (p level 0.001) , and in the area of the ellipse ( p level 0.006) in a within group analysis. Tai chi seemed to be effective in improving physical aspects of quality of life, in postmenopausal women with osteoporosis. Standing balance seems to increase after 6 months Tai chi program, in post-menopausal also if results were not significant. Further studies will be useful to measure effects of a Tai chi longer practice, as literature suggests, and a possible reduction of falling risk and fractures.
In this study hydroxypropylmethylcellulose (HPMC) and sodium carboxymethylcellulose (NaCMC) were used as polymeric carriers to improve controlled release performances of matrix tablets containing a ...soluble drug. The drug release behaviour of the systems containing these two polymers mixture and each material separately was investigated. To evaluate the effect of the dissolution medium pH, on the drug release performance, release tests were conducted at pH 1, 4.5 and 6.8. In vitro release studies demonstrated that the mixture of the two cellulose derivatives enables a better control of the drug release profiles at pH 4.5 and at 6.8 both in term of rate and mechanism. Texture analysis on the swollen tablets helps to understand drug release kinetic and mechanism. In fact, the results obtained confirm that a gel, which is characterized by high strength and consistence is less susceptible to erosion and chains disentanglement and the drug release mechanism is mainly governed by diffusion. On the contrary, gels, which show a low strength and texture, have low resistance to the fluid erosion action and the release of the active molecule is manly due to polymer relaxation and chains disentanglement moving the drug delivery kinetic towards an erosion/relaxation mechanism.
Genetic and environmental factors are thought to contribute to the etiology of the autoimmune disease myasthenia gravis (MG). Viral involvement has long been suspected, but direct evidence of ...involvement has not been found. We recently reported that Toll-like receptor 4 (TLR4)-a key activator of innate immunity-was overexpressed in the thymus of some patients with MG, suggesting that thymic infection by pathogens might be involved in MG pathogenesis. We searched for evidence of intrathymic infection in patients with MG.
Twenty-seven MG thymuses (6 involuted, 7 hyperplastic, 5 thymitis, and 9 thymoma) previously tested for TLR4 expression, 18 nonpathologic control thymuses, and 10 pathologic control thymuses from patients without MG (8 thymoma and 2 hyperplastic) were analyzed for cytomegalovirus, varicella-zoster virus, herpes simplex virus types 1 and 2, eubacteria, respiratory syncytial virus, and enteroviruses using PCR techniques. Immunohistochemistry and double immunofluorescence were used to detect enterovirus capsid protein VP1 in thymic specimens and analyze TLR4 expression in VP1-positive cells.
Poliovirus was detected in 4 MG thymuses (14.8%; 2 thymitis and 2 thymoma). No virus was detected in any control thymus. A linear correlation between plus and minus strand poliovirus RNA levels was observed in all 4 thymuses, suggesting persistent thymic infection. VP1 protein was detected in the cytoplasm of CD68-positive macrophages scattered through thymic medulla in all PV-positive thymuses. VP1 and TLR4 colocalized in infected cells.
Poliovirus-infected macrophages are present in thymus of some patients with myasthenia gravis, suggesting a viral contribution to the intrathymic alterations leading to the disease.
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