1,404 research outputs found

    Electrophysiological Properties of CA1 Pyramidal Neurons along the Longitudinal Axis of the Mouse Hippocampus

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    Evidence for different physiological properties along the hippocampal longitudinal axis is emerging. Here, we examined the electrophysiological features of neurons at different dorso-ventral sites of the mouse CA1 hippocampal region. Cell position was defined with respect to longitudinal coordinates of each slice. We measured variations in neuronal excitability, subthreshold membrane properties and neurotransmitter responses along the longitudinal axis. We found that (i) pyramidal cells of the dorsal hippocampus (DH) were less excitable than those of the ventral hippocampus (VH). Resting Membrane Potential (RMP) was more hyperpolarized and somatic Input Resistance (Ri) was lower in DH compared to VH. (ii) The Paired-pulse ratio (PPR) of focally induced synaptic responses was systematically reduced from the DH to the VH; (iii) Long-term-potentiation was most pronounced in the DH and fell gradually in the intermediate hippocampus and in the VH; (iv) the frequency of miniature GABAergic events was higher in the VH than in the DH; (v) the PPR of evoked inhibitory post-synaptic current (IPSC) was higher in the DH than in the VH. These findings indicate an increased probability of both GABA and glutamate release and a reduced plasticity in the ventral compared to more dorsal regions of the hippocampus

    Antitumor Agents. 5. Synthesis, Structure-Activity Relationships, and Biological Evaluation of Dimethyl-5H-pyridophenoxazin-5-ones, Tetrahydro-5H-benzopyridophenoxazin-5-ones, and 5H-Benzopyridophenoxazin-5-ones with Potent Antiproliferative Activity

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    New antiproliferative compounds, dimethyl-5H-pyrido[3,2-a]phenoxazin-5-ones (1-6), tetrahydro-5Hbenzopyrido[ 2,3-j]phenoxazin-5-ones (7-9), and 5H-benzopyrido[3,2-a]phenoxazin-5-ones (10-12) were synthesized and evaluated against representative human neoplastic cell lines. Dimethyl derivatives 1-6 were more active against carcinoma than leukemia cell lines. The tetrahydrobenzo derivatives 7-9 were scarcely active, whereas the corresponding benzo derivatives 10-12 showed notable cytotoxicity against a majority of the tested cell lines. Molecular modeling studies indicated that the high potency of 10 and 11, the most cytotoxic compounds of the whole series, could be due to the position of the condensed benzene ring, which favors ð-ð stacking interactions with purine and pyrimidine bases in the DNA active site. Biological studies suggested that 10-12 have no effect on human topoisomerases I and II and that they induce arrest at the G2/M phase

    Marfan syndrome: Current perspectives

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    Marfan syndrome (MFS) is a pleiotropic connective tissue disease inherited as an autosomal dominant trait, due to mutations in the FBN1 gene encoding fibrillin 1. It is an important protein of the extracellular matrix that contributes to the final structure of a microfibril. Few cases displaying an autosomal recessive transmission are reported in the world. The FBN1 gene, which is made of 66 exons, is located on chromosome 15q21.1. This review, after an introduction on the clinical manifestations that leads to the diagnosis of MFS, focuses on cardiovascular manifestations, pharmacological and surgical therapies of thoracic aortic aneurysm and/or dissection (TAAD), mechanisms underlying the progression of aneurysm or of acute dissection, and biomarkers associated with progression of TAADs. A Dutch group compared treatment with losartan, an angiotensin II receptor-1 blocker, vs no other additional treatment (COMPARE clinical trial). They observed that losartan reduces the aortic dilatation rate in patients with Marfan syndrome. Later on, they also reported that losartan exerts a beneficial effect on patients with Marfan syndrome carrying an FBN1 mutation that causes haploinsufficiency (quantitative mutation), while it has no significant effect on patients displaying dominant negative (qualitative) mutations. Moreover, a French group in a 3-year trial compared the administration of losartan vs placebo in patients with Marfan syndrome under treatment with beta-receptor blockers. They observed that losartan decreases blood pressure but has no effect on aortic diameter progression. Thus, beta-receptor blockers remain the gold standard therapy in patients with Marfan syndrome. Three potential biochemical markers are mentioned in this review: total homocysteine, serum transforming growth factor beta, and lysyl oxidase. Moreover, markers of oxidative stress measured in plasma, previously correlated with clinical features of Marfan syndrome, may be explored as potential biomarkers of clinical severity

    A Case Based Approach to Clinical Genetics of Thoracic Aortic Aneurysm/Dissection

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    Thoracic aortic aneurysm/dissection (TAAD) is a potential lethal condition with a rising incidence. This condition may occur sporadically; nevertheless, it displays familial clustering in >20% of the cases. Family history confers a six- to twentyfold increased risk of TAAD and has to be considered in the identification and evaluation of patients needing an adequate clinical follow-up. Familial TAAD recognizes a number of potential etiologies with a significant genetic heterogeneity, in either syndromic or nonsyndromic forms of the manifestation. The clinical impact and the management of patients with TAAD differ according to the syndromic and nonsyndromic forms of the manifestation. The clinical management of TAAD patients varies, depending on the different forms. Starting from the description of patient history, in this paper, we summarized the state of the art concerning assessment of clinical/genetic profile and therapeutic management of TAAD patients
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