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971.
972.
Eleonora Mauri Robertino Dilena Antonio Boccazzi Dario Ronchi Daniela Piga Fabio Triulzi Delia Gagliardi Roberta Brusa Irene Faravelli Nereo Bresolin Francesca Magri Stefania Corti Giacomo P. Comi 《BMC neurology》2018,18(1):220
Background
Leber’s hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by visual loss consequent to optic nerve atrophy. In some cases, LHON is associated with heterogeneous neurological extraocular manifestations and is referred to as “Leber plus disease”; rarely it is associated with a multiple sclerosis (MS)-like syndrome known as Harding disease, but no pediatric extraocular acute spinal onset is reported.Case presentation
We describe the case of a 5-year-old girl carrying the G3460A mtDNA mutation who was referred to clinical examination for bilateral upper and lower limb weakness with no sign of optic neuropathy. Spinal cord MRI showed hyperintense signal alterations in T2-weighted and restricted diffusion in DWI sequences in the anterior portion of the cervical and dorsal spinal cord resembling a spinal cord vascular injury. No association between this mutation and pediatric spinal cord lesions has previously been reported. Alternative diagnostic hypotheses, including infective, ischemic and inflammatory disorders, were not substantiated by clinical and instrumental investigations.Conclusions
Our case reports a novel pediatric clinical manifestation associated with the m.3460G?>?A mtDNA mutation, broadening the clinical spectrum of this disease. Early identification of new cases and monitoring of carriers beginning in childhood is important to prevent neurological deterioration and preserve long-term function.973.
974.
Growth at elevated CO2 leads to down-regulation of photosynthesis and altered response to high temperature in Quercus suber L. seedlings 总被引:1,自引:0,他引:1
Faria T.; Wilkins D.; Besford R. T.; Vaz M.; Pereira J. S.; Chaves M. M. 《Journal of experimental botany》1996,47(11):1755-1761
The effects of growth at elevated CO2 on the response to hightemperatures in terms of carbon assimilation (net photosynthesis,stomatal conductance, amount and activity of Rubisco, and concentrationsof total soluble sugars and starch) and of photochemistry (forexample, the efficiency of excitation energy captured by openphotosystem II reaction centres) were studied in cork oak (Quercussuber L.). Plants grown in elevated CO2 (700 ppm) showed a down-regulationof photosynthesis and had lower amounts and activity of Rubiscothan plants grown at ambient CO2 (350 ppm), after 14 monthsin the greenhouse. At that time plants were subjected to a heat-shocktreatment (4 h at 45C in a chamber with 80% relative humidityand 8001000 mol m2 s1 photon flux density).Growth in a CO2-enriched atmosphere seems to protect cork oakleaves from the short-term effects of high temperature. ElevatedCO2 plants had positive net carbon uptake rates during the heatshock treatment whereas plants grown at ambient CO2 showed negativerates. Moreover, recovery was faster in high CO2-grown plantswhich, after 30 min at 25C, exhibited higher net carbon uptakerates and lower decreases in photosynthetic capacity (Amax aswell as in the efficiency of excitation energy captured by openphotosystem II reaction centres (FvJFm than plants grown atambient CO2. The stomata of elevated CO2 plants were also lessresponsive when exposed to high temperature. Key words: Elevated CO2, temperature, acclimation, photosynthesis, Quercus suber L. 相似文献
975.
Cytokine-Regulated Expression of Platelet-Derived Growth Factor Gene and Protein in Cultured Human Astrocytes 总被引:1,自引:0,他引:1
Francesca Ceccherini Silberstein Roberta De Simone Giulio Levi Francesca Aloisi 《Journal of neurochemistry》1996,66(4):1409-1417
Abstract: To elucidate mechanisms regulating the production of platelet-derived growth factor (PDGF) in the CNS, we analyzed the influence of a panel of cytokines on PDGF mRNA and protein levels in astrocyte-enriched cultures from the human embryonic brain and spinal cord. Using a specific ELISA, PDGF AB protein was detected in serum-free astrocyte supernatants and its levels were significantly increased after treatment of the cultures with transforming growth factor-β1 (TGF-β1 ) or tumor necrosis factor-α (TNF-α); the largest increase was detected after combined treatment with the two cytokines. Interleukin-1β (IL-1β) by itself had little or no effect but synergized with TGF-β1 in enhancing PDGF AB production. Supernatants from human astrocyte cultures stimulated the proliferation of rat oligodendrocyte progenitors, and most of the mitogenic activity could be accounted for by PDGF. By northern blot analysis, both PDGF A- and PDGF B-chain mRNAs were detected in untreated astrocytes. PDGF B-chain mRNA levels were increased by TGF-β1 , TNF-α, TNF-α/TGF-β1 , or IL-1β/TGF-β1 , whereas PDGF A-chain mRNA levels were not consistently affected by cytokine treatments. These in vitro data indicate that TGF-β1 , TNF-α, and IL-1β are able to stimulate astrocyte PDGF production. This cytokine network could play a role in CNS development and repair after injury or inflammation. 相似文献
976.
Composition, spatial and temporal variations of Chaetognatha in Guanabara Bay, Brazil 总被引:1,自引:0,他引:1
This paper presents the specific composition and distributionof adult chaetognaths in Guanabara Bay, Brazil. A comparisonhas been made between chaetognath and copepod distribution patterns.Three areas were distinguished within Guanabara Bay: an externalarea, influenced by oceanic waters; an internal area, influencedby fluvial waters; and a transitional area between the two.Monthly samples were collected by horizontal surface hauls usinga conical net with 200µm mesh. Three species were identified:Sagitta friderici, S.enflata and S.hispida. Sagitta fridericiwas the dominant species and occurred throughout the year atthe three areas. Sagitta enflata and S.hispida were limitedto the more saline waters. Generally, greater densities of chaetognathswere observed following copepod peakden sities. Temperatureand salinity associated with copepod abundance were the mostimportant factors affecting the distribution pattern and theabundance of chaetognath species in Guanabara Bay. 相似文献
977.
Marco R. Oggioni Christopher G. Dowson John Maynard Smith Roberta Provvedi Gianni Pozzi 《Plasmid》1996,35(3):156-163
Tetracycline resistance genes of the M class,tet(M), are typically found on mobile genetic elements as the conjugative transposons of gram-positive bacteria. By comparing the sequences of eight differenttet(M) genes (fromEnterococcus faecalis, Streptococcus pneumoniae, Staphylococcus aureus, Ureaplasma urealyticum,andNeisseria), a mosaic structure was detected which could be traced to two distinct alleles. The two alleles displayed a divergence of 8% and a different G/C content. The block structure of these genes provides evidence for the contribution of homologous recombination to the evolution and the heterogeneity of thetet(M) locus. Unlike described cases of chromosomally located mosaic loci,tet(M) is a relatively recently acquired determinant in the species examined and it would appear that mosaic structure withintet(M) has evolved after acquisition of the gene by the mobile genetic elements upon which it is located. 相似文献
978.
Recently published chemical shifts for haem 13C nuclei in bovine ferricytochrome b
55 (Lee KB, Kweon J, Park H (1995) Assignment of hyperfine-shifted heme carbon resonances in ferricytochrome b
5. FEBS Lett. 367:77–80) are analysed in terms of haem molecular orbitals with perturbed D4h symmetry. Since a crystal structure of this protein is available, together with extensive 1H assignments both in the oxidised and reduced forms, the paramagnetic shifts can be separated into dipolar and Fermi contact contributions by using an empirical magnetic susceptibility tensor. The results are compared with the orientation of the tensor and the geometry of the haem ligands. This comparison casts doubt on one of the 13C assignments and demonstrates that the asymmetry of the haem electronic structure is dominated by the influence of both of the His ligands. The 13C chemical shifts of two haem methyl groups in the minor form of the protein, in which the haem is approximately rotated by 180° about its 5CH15CH axis, are also evaluated. 相似文献
979.
Alessandra Casati Roberta Riboni Jessica Caprioli Fiorella Nuzzo Chiara Mondello 《Chromosoma》1995,104(2):137-142
Anomalies of chromatin condensation, such as fragmentation, uncoiling and pulverization, were observed in XP9UV25, a xeroderma pigmentosum fibroblast clone in which a high proportion of cells carried an end-to-end dicentric chromosome, dic (5;16) (p15.2;q24), that gives rise during propagation in culture to a variety of dicentric and monocentric derivatives. The coiling anomaly affected exclusively part of a rearranged chromosome, in particular the region previously involved in breakage events. The heterochromatic 16q region, which is a preferential breakpoint in the formation of dicentric and monocentric derivatives, was consistently the limit of the uncoiled or pulverized regions. This observation suggests that the anomalous chromatin behavior could derive from alteration of a region relevant for the correct condensation of the chromosome. In XP9UV25 the frequency of nuclei with associated micronuclei increased with time in culture, in parallel with that of mitoses with dicentric chromosomes. In situ hybridization with DNA probes specific for chromosomes 5 and 16 revealed hybridization signals in about 40% of micronuclei. Since the frequency of micronuclei is about ten times less than that of dicentrics, it is probable that only the rearranged chromosomes undergoing coiling anomalies are excluded in micronuclei. 相似文献
980.
Acid adaptation in Streptococcus mutans UA159 alleviates sensitization to environmental stress due to RecA deficiency 总被引:2,自引:0,他引:2
Robert G QuiveyJr. Roberta C Faustoferri K. Anne Clancy Robert E Marquis 《FEMS microbiology letters》1995,126(3):257-262
Abstract A RecA-deficient stain of Streptococcus mutans , isolated previously, was found to be more susceptible than the prototroph organism to acid killing and also showed reduced colony-forming ability on sucrose-containing medium. The deficient strain was able to grow in chemostat culture at a low pH value of 5 and did not show reduced capacity to produce acid in standard pH-drop experiments with excess glucose. Moreover, it was able to undergo an adaptive response when grown at a low pH to become more resistant to acid killing and also to killing by ultraviolet radiation or hydrogen peroxide. In fact, after adaptation, it was nearly as resistant as the prototroph strain. These findings were interpreted, in part, in terms of an acid-inducible DNA repair system which functions independently of RecA. 相似文献