Changes of mitochondrial membrane proteins in rat cerebellum during aging

Qualitative and quantitative changes of mitochondrial membrane proteind during aging were investigated. Free (non-synaptic) mitochondria were purified from rat cerebellum at different ages (4, 8, 12, 16, 20, and 24 months). Mitochondrial outer membrane (OM), inner membrane (IM) and matrix (MX) were separated and the proteins were extracted and analyzed by gel-electrophoresis.After staining, the gels were scanned densitometrically to quantify the proteins. No significant changes in the quantity of OM or MX protein subunits were observed, while serveral statistically significant quantitative changes in IM proteins with age were found. These age-dependent modifications of inner membrane mitochondrial proteins may play an important role in energy transduction, transport systems and regulatory enzymatic activities in mitochondria.     

Effect of alpha-adrenoreceptors in the control of spontaneous motility and morphine withdrawal syndrome.

The effects of different alpha-2 agonists on the spontaneous motility in naive and morphine tolerant mice were studied. Clonidine caused a reduction at the lower (1-3 micrograms Kg-1 i.p.) and higher (100 micrograms Kg-1 i.p.) doses and no effect at 10-30 micrograms Kg-1 i.p. in naive mice, while an increase was found at the intermediate doses (10-30 micrograms Kg-1 i.p.) in morphine tolerant mice. The clonidine-induced inhibition on spontaneous motility at the lower and higher doses was prevented both in naive and tolerant mice by idazoxan pretreatment. In morphine-treated animals the increase induced by clonidine was antagonized by prazosin. The action of guanabenz and guanfacine on locomotion differed from clonidine, by producing inhibition only at higher doses (100-300 micrograms Kg-1 i.p.). Clonidine, but not guanfacine or guanabenz, prevented the withdrawal syndrome precipitated by naloxone. Thus the only alpha-2 agonistic properties do not appear sufficient to explain the prevention of morphine abstinence by clonidine in mice, which can represent a single model to screen anti-withdrawal drugs.     

Preparation and biological activity of taxol acetates

Synthesis and biological activity of 2′-acetyltaxol and 7-acetyltaxol are reported. Activity is measured $\text{in}\text{vivo}$ by cytotoxicity toward the macrophage-like cell line J774.2, and $\text{in}\text{vitro}$ by promotion of microtubule assembly in the absence of exogenous GTP. Addition of an acetyl moiety at C-2′ results in loss of $\text{in}\text{vitro}$ activity but not cytotoxicity. The properties of 7-acetyltaxol are similar to those of taxol in its effects on cell replication and on $\text{in}\text{vitro}$ microtubule polymerization. Therefore a free hydroxyl group at C-7 is not required for $\text{in}\text{vitro}$ activity and this position is available for structural modifications.     

Age-dependent modifications of mitochondrial proteins in cerebral cortex and striatum of rat brain

The protein composition of free mitochondria purified from cerebral cortex and striatum during aging was analyzed by gel electrophoresis. Mitochondria were isolated from cerebral cortex and striatum of 4-, 12-, and 24-month-old rat brain. The percent amount of mitochondrial proteins after gel-electrophoretic separation was determined densitometrically. A significant decrease in the amount of two polypeptides (with molecular weights of 20 and 16 kDa, respectively) in both brain regions during aging was found. The decrease was higher in the striatum indicating a greater vulnerability of this brain area to the aging process. The age-dependent modifications of mitochondrial proteins observed may play an important role in several mitochondrial functions, such as energy transduction and transport processes as well as in structural changes occurring with age, causing altered membrane permeability and fluidity.     

Multiple supramolecular structures formed by interaction of actin with protamine

When protamine is added to actin, different supramolecular structures are formed depending on the molar ratio of the two proteins and of the ionic strength of the medium. At low ionic strength, and going from a molar ratio of protamine to G-actin of 4:1, 2:1 and 1:1, globular aggregates are first converted into extended structures and then to long threads in which the constituent ATP–G-actin is rapidly exchangeable with the actin of the medium. At high ionic strength {Tyrode [(1910) Arch. Int. Pharmacodyn. Ther. 20, 205–212] solution}, starting from G-actin and protamine in the 1:1 molar ratio, long ropes are formed that can be resolved into intertwining filaments of 4–5nm diameter. The addition of protamine in a 1:1 molar ratio to a solution of F-actin in Tyrode solution causes the breakage of the actin filaments, which is also revealed by the decrease of the viscosity of the solution and the formation of ordered latero-lateral aggregates. The structures formed by reaction of protamine with G-actin can be separated from free G-actin and protamine by filtration through 0.45μm-pore-size Millipore filters. This technique has been exploited to study the exchange reaction between free actin and the actin–protamine complexes. For these studies the 1:1 actin–protamine complex formed at low ionic strength and the 2:1 actin–protamine complex formed in the presence of 23nm-free Mg²⁺ have been selected. In the first case the exchange reaction is practically complete in the dead time of the experiment (20s). In the second case, where the complex operates like a true ATPase, the rate of the exchange is initially comparable with the rate of the ATP cleavage. Later on, however, the complex undergoes a change and the rate of the exchange between free actin and the actin bound to protamine becomes lower than the rate of the ATPase reaction. It is proposed that the ATP exchanges for ADP directly on the G-actin bound in the complex.     

Nusinersen treatment and cerebrospinal fluid neurofilaments: An explorative study on Spinal Muscular Atrophy type 3 patients

The antisense oligonucleotide Nusinersen has been recently licensed to treat spinal muscular atrophy (SMA). Since SMA type 3 is characterized by variable phenotype and milder progression, biomarkers of early treatment response are urgently needed. We investigated the cerebrospinal fluid (CSF) concentration of neurofilaments in SMA type 3 patients treated with Nusinersen as a potential biomarker of treatment efficacy. The concentration of phosphorylated neurofilaments heavy chain (pNfH) and light chain (NfL) in the CSF of SMA type 3 patients was evaluated before and after six months since the first Nusinersen administration, performed with commercially available enzyme-linked immunosorbent assay (ELISA) kits. Clinical evaluation of SMA patients was performed with standardized motor function scales. Baseline neurofilament levels in patients were comparable to controls, but significantly decreased after six months of treatment, while motor functions were only marginally ameliorated. No significant correlation was observed between the change in motor functions and that of neurofilaments over time. The reduction of neurofilament levels suggests a possible early biochemical effect of treatment on axonal degeneration, which may precede changes in motor performance. Our study mandates further investigations to assess neurofilaments as a marker of treatment response.     

Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

Printed in the Holiday Mood

Teachers' careers are often considered to consist of two parts: pre-service and in-service. In-service refers to the entire time between a teacher's entry and exit from the profession. Recent research suggests teachers' careers actually consistent of several parts, known as phases or stages and, collectively, as the career cycle. This further suggests that as they pass through different stages, teachers' professional development needs may change. This article presents a review of literature on the career cycle, examines the portion known as the “second stage,” and discusses the policy and professional development implications for music teachers.     

Prognostic factors and predictors of outcome in patients with COVID-19 and related pneumonia: a retrospective cohort study

The aim of the present study was to simultaneously assess several potential predictors of outcome (co-morbidity, previous and in-hospital treatment, radiologic Brixia score) in patients with COVID-19.This retrospective cohort study included 258 consecutive patients with confirmed COVID-19 admitted to a medical ward at Montichiari Hospital, Brescia, Italy from February 28th to April 30rd, 2020. Patients had SARS-CoV-2 related pneumonia with respiratory failure, and were treated with hydroxychloroquine and lopinavir plus ritonavir. In some patients, additional treatment with tocilizumab, dexamethasone and enoxaparin was adopted. Outcomes (death or recovery) were assessed at the end of the discharge period or at the end of the follow-up (August 2020).During hospitalization, 59 patients died, while 6 died after discharge. The following variables were demonstrated to be associated with a worse prognosis: Radiologic Brixia score higher than 8, presence at baseline of hypertension, diabetes, chronic obstructive pulmonary disease, heart disease, cancer, previous treatment with ACE-inhibitors or anti-platelet drugs. Anticoagulant treatment during hospital admission with enoxaparin at a dose higher than 4000 U once daily was associated with a better prognosis.In conclusion, our study demonstrates that some co-morbidities and cardiovascular risk factors may affect prognosis. The radiologic Brixia score may be a useful tool to stratify the risk of death at baseline. Anticoagulant treatment with enoxaparin might be associated to a clinical benefit in terms of survival in patients with COVID-19.