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191.
Oxidative stress in diabetes-induced endothelial dysfunction involvement of nitric oxide and protein kinase C 总被引:3,自引:0,他引:3
Pricci F Leto G Amadio L Iacobini C Cordone S Catalano S Zicari A Sorcini M Di Mario U Pugliese G 《Free radical biology & medicine》2003,35(6):683-694
Reactive oxygen species (ROS) formation plays a major role in diabetes-induced endothelial dysfunction, though the molecular mechanism(s) involved and the contribution of nitric oxide (NO) are still unclear. This study using bovine retinal endothelial cells was aimed at assessing (i) the role of oxygen-dependent vs. NO-dependent oxidative stress in the endothelial cell permeability alterations induced by the diabetic milieu and (ii) whether protein kinase C (PKC) activation ultimately mediates these changes. Superoxide, lipid peroxide, and PKC activity were higher under high glucose (HG) vs. normal glucose throughout the 30 d period. Nitrite/nitrate and endothelial NO synthase levels increased at 1 d and decreased thereafter. Changes in monolayer permeability to 125I-BSA induced by 1 or 30 d incubation in HG or exposure to advanced glycosylation endproduct were reduced by treatment with antioxidants or PKC inhibitors, whereas NO blockade prevented only the effect of 1 d HG. HG-induced changes were mimicked by a PKC activator, a superoxide generating system, an NO and superoxide donor, or peroxynitrite (attenuated by PKC inhibition), but not a NO donor. The short-term effect of HG depends on a combined oxidative and nitrosative stress with peroxynitrite formation, whereas the long-term effect is related to ROS generation; in both cases, PKC ultimately mediates permeability changes. 相似文献
192.
Double muscling in Marchigiana beef breed is caused by a stop codon in the third exon of myostatin gene 总被引:10,自引:0,他引:10
Cinzia?MarchitelliEmail author Maria?Carmela?Savarese Alessandra?Crisà Alessandro?Nardone Paolo?Ajmone?Marsan Alessio?Valentini 《Mammalian genome》2003,14(6):392-395
Double muscling is a partially recessive trait present in some beef breeds. It shows a high frequency in some breeds, while in others the frequency is low, and double-muscled individuals are rare. The double muscling is caused by an allelic series of mutations that cause a loss of function of the myostatin gene ( GDF8). We describe here a new mutation in the myostatin gene in Marchigiana breed, a typical beef breed of Central Italy, in which rare double-muscling individuals have been described. A PCR product of the third exon was sequenced in subjects phenotypically showing double muscling, and a G > T transversion was discovered that introduces a premature stop codon. The variant found adds to the large series of mutations present in cattle, and particularly to the only two causative of double muscling in the third exon. A PCR-RFLP test is described for the rapid and effective identification of both heterozygous and homozygous subjects. It was applied to a larger survey carried on the same and also in two other beef breeds, Chianina and Romagnola. Further individuals carrying the new variant were found in Marchigiana, but none in the other breeds. The results may be important for a better comprehension of the role of myostatin in muscular development, for commercial use and for the inference of phylogeny of this gene. 相似文献
193.
Di Fabio R Tranquillini E Bertani B Alvaro G Micheli F Sabbatini F Pizzi MD Pentassuglia G Pasquarello A Messeri T Donati D Ratti E Arban R Dal Forno G Reggiani A Barnaby RJ 《Bioorganic & medicinal chemistry letters》2003,13(21):3863-3866
To identify neuroprotective agents after stroke, new substituted tetrahydroquinoline derivatives were designed as antagonists of the glycine binding site associated to the NMDA receptor, satisfying the key pharmacophoric requirements. In particular, the racemate 3c exhibited outstanding in vivo activity in the MCAo model in rats, when given iv both pre- and post-ischemia. Pure enantiomers 3c-(+) and 3c-(-) have been prepared following an original synthetic route. Despite the significant difference of activity observed in vitro, they shown similar neuroprotective profile in the MCAo model in rats. 相似文献
194.
Laura Barsanti Alessandra Bastianini Vincenzo Passarelli Mario R. Tredici Paolo Gualtieri 《Journal of applied phycology》2000,12(3-5):515-520
The effects of growth conditions on fatty acid profilewere examined in the photosynthetic wild type and inthe spontaneous non-photosynthetic WZSL mutant of theunicellular flagellate Euglena gracilis. Inthe light, the amount of polyunsaturated fatty acids(PUFAs) is higher in the wild type than in the mutant,independent of the carbon source. Among importantPUFAs, linolenic acid (18:3 3) is present inhigh amount only in wild type cells grown in the lightwith any of the tested carbon sources. The content ofother PUFAs, such as arachidonic acid (20:46), EPA (20:5 3) and DHA (22:63), is not correlated with the presence oflight or chloroplasts.The main effect of the dark in both strains is tolower the content of PUFAs and mono-unsaturated fattyacids and to increase the content of saturated fattyacids with all the carbon sources. 相似文献
195.
Functional characterization of Ape1 variants identified in the human population 总被引:15,自引:0,他引:15 下载免费PDF全文
Hadi MZ Coleman MA Fidelis K Mohrenweiser HW Wilson DM 《Nucleic acids research》2000,28(20):3871-3879
Apurinic/apyrimidinic (AP) sites are common mutagenic and cytotoxic DNA lesions. Ape1 is the major human repair enzyme for abasic sites and incises the phosphodiester backbone 5′ to the lesion to initiate a cascade of events aimed at removing the AP moiety and maintaining genetic integrity. Through resequencing of genomic DNA from 128 unrelated individuals, and searching published reports and sequence databases, seven amino acid substitution variants were identified in the repair domain of human Ape1. Functional characterization revealed that three of the variants, L104R, E126D and R237A, exhibited ~40–60% reductions in specific incision activity. A fourth variant, D283G, is similar to the previously characterized mutant D283A found to exhibit ~10% repair capacity. The most common substitution (D148E; observed at an allele frequency of 0.38) had no impact on endonuclease and DNA binding activities, nor did a G306A substitution. A G241R variant showed slightly enhanced endonuclease activity relative to wild-type. In total, four of seven substitutions in the repair domain of Ape1 imparted reduced function. These reduced function variants may represent low penetrance human polymorphisms that associate with increased disease susceptibility. 相似文献
196.
Sokoloff MH Nardin A Solga MD Lindorfer MA Sutherland WM Bankovich AJ Zhau HE Chung LW Taylor RP 《Cancer immunology, immunotherapy : CII》2000,49(10):551-562
Purpose: The goal of this research is to determine the feasibility of an immunotherapeutic approach based on the use of monoclonal
antibodies (mAb) to target complement activation fragments on opsonized cancer cells. Methods: We investigated whether treatment of LNCaP and C4-2 human prostate cancer cell lines with normal human serum would allow
for deposition of sufficient amounts of the complement-activation protein C3b and its fragments [collectively referred to
as C3b(i)] such that these proteins could serve as cancer-cell-associated antigens for targeting by mAb. Radioimmunoassays,
flow cytometry, and magnetic purging with specific immunomagnetic beads were used for the analyses. Results: In vitro opsonization of human prostate cancer cells with normal human serum resulted in deposition of C3b(i) in sufficient
quantity (approx. 100,000 molecules/cell) for the cells to be targeted in a variety of protocols. We found that 51Cr-labeled and C3b(i)-opsonized cancer cells could be specifically purged at high efficiency (95%–99%) using anti-C3b(i) mAb
covalently coupled to magnetic beads. Flow-cytometry experiments indicated that most normal white cells were not removed under
similar conditions. Opsonization of cancer cells with sera from men with prostate cancer led to lower levels of cell-associated
IgM and, subsequently, lower amounts of C3b(i) deposited than in normal subjects. Prototype experiments suggested that this
deficiency could be corrected by addition of IgM from normal donor plasma. Conclusion: mAb directed against complement-activation products may provide new opportunities to deliver diagnostic and therapeutic agents
selectively to cancer cells and tumor deposits. These opportunities may include ex vivo purging of C3b(i)-opsonized cancer
cells prior to autologous bone marrow or stem cell transplantation.
Received: 17 February 2000 / Accepted: 1 August 2000 相似文献
197.
Comparison of Free-Living Amoebae in Hot Water Systems of Hospitals with Isolates from Moist Sanitary Areas by Identifying Genera and Determining Temperature Tolerance 总被引:5,自引:2,他引:3 下载免费PDF全文
Ute Rohr Susanne Weber Rolf Michel Fidelis Selenka Michael Wilhelm 《Applied microbiology》1998,64(5):1822-1824
Legionella-contaminated hot water systems and moist sanitary areas in six hospitals were sampled for amoebae by following a standardized collection protocol. Genus identifications and temperature tolerance determinations were made. Amoebae identified as Hartmannella vermiformis (65%), Echinamoebae spp. (15%), Saccamoebae spp. (12%), and Vahlkampfia spp. (9%) were detected in 29 of 56 (52%) hot water samples. Twenty-three of 49 (47%) swabs obtained from moist areas were amoeba positive. The following genera were identified: Acanthamoeba (22%), Naegleria (22%), Vahlkampfia (20%), Hartmannella (15%), and Vanella (7%). The temperature tolerance of amoebae from hot water systems was strikingly different from that of amoebae from moist areas. At 44°C on agar, 59% of amoebic isolates sampled from hot water systems showed growth. The corresponding value for isolates from moist areas was only 17%. Six Acanthamoeba isolates from the moist areas were considered potential pathogens. Four Hartmannella and two Saccamoeba isolates from hot water could be cultured at 53°C. 相似文献
198.
Ultrastructure of the female gonad of two temnocephalids (Platyhelminthes,Rhabdocoela) 总被引:2,自引:2,他引:0
The female gonad of Temnocephala dendyi and T. minor consists of a single germarium and two rows of vitellaria. It is enveloped
by an extracellular lamina and accessory cells. Accessory cells are only peripherally located in the germarium while their
cytoplasmic projections also fill the spaces between vitellocytes in the vitellarium. The main feature of oocyte maturation
is the appearance of chromatoid bodies and the development of rough endoplasmic reticulum (R.E.R.) and Golgi complexes which
appear to be correlated with the production of double-structured egg granules. The egg granules, which are localized in the
cortical cytoplasm of mature oocytes, contain glycoproteins, are devoid of polyphenols and are similar in structure and composition
to the cortical granules observed in some Digenea and Monogenea. Vitellocytes are typical secretory cells with well-developed
R.E.R. and Golgi complexes which are involved in the production of shell globules and yolk. The multigranular pattern and
the polyphenolic composition of the shell globules of the temnocephalids investigated are similar to those observed in other
rhabdocoels, and in some Prolecithophora and Neodermata. This feature may represent a synapomorphy shared by these taxa.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
199.
Alessandra de Cupis Paolo Pirani Laura Fazzuoli Roberto E. Favoni 《In vitro cellular & developmental biology. Animal》1998,34(10):836-843
Summary Growth rate, morphology, and responsiveness to mitogenic stimuli and pharmacological treatments were evaluated in early and
late cell passages derived from the same clone of the widely used MCF-7 human breast adenocarcinoma cell line. Our results
indicate dissimilarities between early (E) and late (L) passages for some of the parameters analyzed. The cells that underwent
many subcultivations grew faster than the others; both appeared homogeneous in size and shape. The E cells, subcultured for
almost 1 yr, displayed higher sensitivity to the mitogenic action of both estradiol, according to the level of estrogen receptor,
and insulin-like growth factor-I than did the L cells, kept in culture for more than 10 yr. Cell responsiveness to two drugs,
a novel steroid antiestrogen and a polysulfonated distamycin A derivative, was more pronounced in the early cultures only
at the longer time of exposure to the higher concentration of the estrogen antagonist. In addition, a drug-induced inhibition
of insulin-like growth factor-I binding to its receptor was shown in both E and L cells, the latter being less sensitive than
the former when exposed to the antiestrogen. Finally, MCF-7 E and L cells showed similar behavior when drug-induced apoptosis
was tested. 相似文献
200.
Isabella Di Lernia Alessandra Morana Antonio Ottombrino Stefania Fusco Mosè Rossi M. De Rosa 《Extremophiles : life under extreme conditions》1998,2(4):409-416
Enzymes that convert starch and dextrins to α,α-trehalose and glucose were found in cell homogenates of the hyperthermophilic
acidophilic archaeon Sulfolobus shibatae DMS 5389. Three enzymes were purified and characterized. The first, the S. shibatae trehalosyl dextrin-forming enzyme (SsTDFE), transformed starch and dextrins to the corresponding trehalosyl derivatives with
an intramolecular transglycosylation process that converted the glucosidic linkage at the reducing end from α-1,4 to α-1,1.
The second, the S. shibatae trehalose-forming enzyme (SsTFE), hydrolyzed the α-1,4 linkage adjacent to the α-1,1 bond of trehalosyl dextrins, forming
trehalose and lower molecular weight dextrins. These two enzymes had molecular masses of 80 kDa and 65 kDa, respectively,
and showed the highest activities at pH 4.5. The apparent optimal temperature for activity was 70°C for SsTDFE and 85°C for
SsTFE. The third enzyme identified was an α-glycosidase (SsαGly), which catalyzed the hydrolysis of the α-1,4 glucosidic linkages
in starch and dextrins, releasing glucose in a stepwise manner from the nonreducing end of the polysaccharide chain. The enzyme
had a molecular mass of 313 kDa and showed the highest activity at pH 5.5 and at 85°C.
Received: October 29, 1997 / Accepted: April 29, 1998 相似文献