排序方式: 共有149条查询结果,搜索用时 15 毫秒
31.
Cristina Garcia-Frigola Maria Isabel Carreres Celia Vegar Eloisa Herrera 《BMC developmental biology》2007,7(1):103
Background
The neural retina is a highly structured tissue of the central nervous system that is formed by seven different cell types that are arranged in layers. Despite much effort, the genetic mechanisms that underlie retinal development are still poorly understood. In recent years, large-scale genomic analyses have identified candidate genes that may play a role in retinal neurogenesis, axon guidance and other key processes during the development of the visual system. Thus, new and rapid techniques are now required to carry out high-throughput analyses of all these candidate genes in mammals. Gene delivery techniques have been described to express exogenous proteins in the retina of newborn mice but these approaches do not efficiently introduce genes into the only retinal cell type that transmits visual information to the brain, the retinal ganglion cells (RGCs). 相似文献32.
Coutinho LB Gomes AO Araújo EC Barenco PV Santos JL Caixeta DR Silva DA Cunha-Júnior JP Ferro EA Silva NM 《International journal for parasitology》2012,42(4):341-352
Congenital toxoplasmosis is associated with adverse pregnancy outcome. Despite the type 1 immune response, C57BL/6 mice are more susceptible than BALB/c mice to Toxoplasma gondii infection. Additionally, successful pregnancy appears to be correlated with type 2 T helper maternal immunity and regulatory T cells. In order to investigate the mechanisms of susceptibility/resistance to congenital toxoplasmosis in mice with different genetic backgrounds and the influence of inducible nitric oxide synthase in pregnancy outcome, groups of C57BL/6, BALB/c and C57BL/6 iNOS(-/-) females were orally infected with T. gondii ME-49 strain on day 1 of pregnancy and were sacrificed on day 8 p.i. and day 19 p.i. The uterus and placenta were evaluated for the foetal resorption rate, parasite load, immunological and histological changes. C57BL/6 mice presented inflammatory foci in the decidua (endometrium) of the uterus at a higher frequency than BALB/c mice on day 8 p.i., and a large number of pregnant C57BL/6 mice presented necrotic implantation sites. The parasite was seldom found in the uterus or placenta of either lineage of mice. Interestingly, there was no observed difference in inducible nitric oxide synthase expression in the uterus and placenta of infected mice. In addition, higher levels of TNF-α were detected in serum samples from C57BL/6 mice compared with BALB/c mice. Accordingly, C57BL/6 mice presented with levels of 90% abortion compared with 50% in BALB/c mice on day 19 p.i. C57BL/6 iNOS(-/-) mice showed low placental parasite counts and high absorption rates, similar to wild type mice. The data suggest that the impaired pregnancy outcome due to T. gondii infection in C57BL/6 mice could be associated with a higher inflammatory response leading to cell apoptosis and necrosis of implantation sites compared with BALB/c mice, and this phenomenon was not due to inducible nitric oxide synthase expression in the decidua. 相似文献
33.
Calabrese V Cornelius C Maiolino L Luca M Chiaramonte R Toscano MA Serra A 《Neurochemical research》2010,35(12):2208-2217
Ménière’s disease (MD) is characterized by the triad of fluctuating hearing loss, episodic vertigo and tinnitus, and by endolymphatic
hydrops found on post-mortem examination. Increasing evidence suggests that oxidative stress is involved in the development
of endolymphatic hydrops and that cellular damage and apoptotic cell death might contribute to the sensorineural hearing loss
found in later stages of MD. While excess reactive oxygen species (ROS) are toxic, regulated ROS, however, play an important
role in cellular signaling. The ability of a cell to counteract stressful conditions, known as cellular stress response, requires
the activation of pro-survival pathways and the production of molecules with anti-oxidant, anti-apoptotic or pro-apoptotic
activities. Among the cellular pathways conferring protection against oxidative stress, a key role is played by vitagenes,
which include heat shock proteins (Hsps) as well as the thioredoxin/thioredoxin reductase system. In this study we tested
the hypothesis that in MD patients measurable increases in markers of cellular stress response and oxidative stress in peripheral
blood are present. This study also explores the hypothesis that changes in the redox status of glutathione, the major endogenous
antioxidant, associated with abnormal expression and activity of carbonic anhydrase can contribute to increase oxidative stress
and to disruption of systemic redox homeostasis which can be associated to possible alterations on vulnerable neurons such
as spiral ganglion neurons and consequent cellular degeneration. We therefore evaluated systemic oxidative stress and cellular
stress response in patients suffering from Meniere’s disease (MD) and in age-matched healthy subjects. Systemic oxidative
stress was estimated by measuring protein oxidation, such as protein carbonyls (PC) and 4-hydroxynonenal (HNE) in lymphocytes
of MD patients, as well as ultraweak luminescence (UCL) as end-stable products of lipid oxidation in MD plasma and lymphocytes,
as compared to age-matched controls, whereas heat shock proteins Hsp70 and thioredoxin (Trx) expression were measured in lymphocytes
to evaluate the systemic cellular stress response. Increased levels of PC (P < 0.01) and HNE (P < 0.05) have been found in lymphocytes from MD patients with respect to control group. This was paralleled by a significant
induction of Hsp70, and a decreased expression of Trx (P < 0.01), whereas a significant decrease in both plasma and lymphocyte ratio reduced glutathione GSH) vs. oxidized glutathione
(GSSG) (P < 0.05) were also observed. In conclusion, patients affected by MD are under condition of systemic oxidative stress and the
induction of vitagenes Hsp70 is a maintained response in counteracting the intracellular pro-oxidant status generated by decreased
content of GSH as well as expression of Trx. The search for novel and more potent inducers of vitagenes will facilitate the
development of pharmacological strategies to increase the intrinsic capacity of vulnerable ganglion cells to maximize antidegenerative
mechanisms, such as stress response and thus cytoprotection. 相似文献
34.
35.
Eloisa Helena A. Andrade Claudio N. Alves Elsie F. Guimarães Léa Maria M. Carreira José Guilherme S. Maia 《Biochemical Systematics and Ecology》2011,39(4-6):669-675
Twelve samples of air-dried aerial parts of Piper dilatatum L. C. Rich yielded essential oils and their volatile constituents were analyzed by GC and GC–MS. Sesquiterpenes, both hydrocarbons and oxygenated, were the most highly represented classes, the former ranging from 31.5% to 87.7% and the latter varying from 1.8% to 49.4%. Using hierarchical cluster analysis, the oils were divided into seven groups, whose main constituents were: (E)-caryophyllene, α-cadinol and germacrene D (group A); spathulenol, bicyclogermacrene and (Z)-β-ocimene, (group B); spathulenol, germacrene D and (E)-nerolidol, (group C); germacrene D, limonene, α-phellandrene and bicyclogermacrene (group D); β-elemene, germacrene D and β-pinene (group E); curzerene, p-cymene and α-eudesmol (group F); and (Z)-α-bisabolene, curzerene and germacrene D (group G). We have seen that Piper oils from the Amazon present as major constituents terpenoids and phenylpropanoids, always with the predominance of one over another. The essential oils of P. dilatatum presented in this paper, containing only mono- and sesquiterpenes as its major components, is further chemotaxonomic evidence of this dichotomy in the Piper genus. 相似文献
36.
Eloisa D. Castro Pedro Paulo M. Mathias Wagner L. Batista Alex Yuri S. Sato Maytê S. Toledo Victor T. de Almeida Marli F. Curcio Paulo E. da Costa Arnold Stern Hugo P. Monteiro 《Cell biology international》2022,46(1):158-169
Low levels of nitric oxide (NO) produced by constitutively expressed inducible NO synthase (NOS2) in tumor cells may be an important factor in their development. NOS2 expression is associated with high mortality rates for various cancers. Alternative splicing of NOS2 down-regulates its enzymatic activity, resulting in decreased intracellular NO concentrations. Specific probes to detect alternative splicing of NOS2 were used in two isogenic human colon cancer cell lines derived either from the primary tumor (SW480) or from a lymph node metastasis (SW620). Splicing variant of NOS2 S3, lacking exons 9, 10, and 11, was overexpressed in SW480 cells. NOS2 S3 was silenced in SW480 cells. Flow-cytometry analysis was used to estimate the intracellular NO levels and to analyze the cell cycle of the studied cell lines. Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine apoptosis and autophagy markers. SW480 and SW620 cells expressed NOS2 S3. Overexpression of the NOS2 S3 in SW480 cells downregulated intracellular NO levels. SW480 cells with knocked down NOS2 S3 (referred to as S3C9 cells) had higher intracellular levels of NO compared to the wild-type SW480 cells under serum restriction. Higher NO levels resulted in the loss of viability of S3C9 cells, which was associated with autophagy. Induction of autophagy by elevated intracellular NO levels in S3C9 cells under serum restriction, suggests that autophagy operates as a cytotoxic response to nitrosative stress. The expression of NOS2 S3 plays an important role in regulating intracellular NO production and maintaining viability in SW480 cells under serum restriction. These findings may prove significant in the design of NOS2/NO-based therapies for colon cancer. 相似文献
37.
Girotto JA Chiaramonte M Menon NG Singh N Silverman R Tufaro AP Nahabedian M Goldberg NH Manson PN 《Plastic and reconstructive surgery》2003,112(1):106-114
Secondary repair of recurrent ventral hernia is difficult, and success depends on re-establishing the functional integrity of the abdominal wall. Current techniques used for closure of these defects have documented recurrence rates as high as 54 percent. The authors' 8-year experience utilizing variations of the components separation technique for autologous tissue repair of recalcitrant hernias emphasizes that recurrent or recalcitrant hernias benefit from the creation of a dynamic abdominal wall. A total of 389 patients were retrospectively identified as having abdominal wall defects, and 284 of these patients met the selection criteria. Study patients were grouped according to the type of surgical repair used. The recurrence rate was 20.7 percent over all study groups and was directly related to the extent of repair required. Group 1 patients (wide tissue undermining) had a recurrence rate of only 15 percent, while in group 2 (complete components separation), the recurrence rate was 22 percent. Group 3 patients (interpositional fascia lata graft) had a 29 percent recurrence rate. Time to recurrence was also significantly different across treatment groups, with study group 3 experiencing earlier hernia recurrence. The most frequent postoperative complication was wound infection, which was directly related to the repair performed. The relative odds of recurrence versus the risk factors of age, sex, perioperative steroid use, wound infection, defect size, and the presence of enterocutaneous fistula were studied with a logistic regression analysis. These factors did not possess statistical significance for predicting hernia recurrence. The preoperative presence of mesh was independently significant for hernia recurrence, increasing the relative odds 2.2 times (p = 0.01). Similarly, when other risk factors were controlled for, increasing the complexity of the treatment group, from study group 1 (wide tissue undermining) to study group 3 (interpositional fascia lata graft), also increased the odds of hernia recurrence 1.5-fold per group (p = 0.04). Average inpatient cost was $24,488. The length of inpatient stay ranged from 2 to 172 days (average, 12.8 days). The length of inpatient stay and costs were directly related to the extent of repair required. Using the analysis of variance test for multiple factors, the presence of an enterocutaneous fistula (p = 0.0014) or a postoperative wound infection (p = 0.008) independently increased the length of inpatient stay and hospital costs. A total of 108 successfully repaired patients were contacted by telephone and agreed to participate in a self-reported satisfaction survey. The patients noticed improvements in the appearance of their abdomen, in their postoperative emotional state, and in their ability to lift objects, arise from a chair or a bed, and exercise. These results suggest that recalcitrant hernia defects should be solved, when possible, by reconstructing a dynamic abdominal wall. 相似文献
38.
Clinical applications of three-dimensional photography in breast surgery 总被引:15,自引:0,他引:15
Galdino GM Nahabedian M Chiaramonte M Geng JZ Klatsky S Manson P 《Plastic and reconstructive surgery》2002,110(1):58-70
Three-dimensional imaging in breast surgery has several uses clinically. The most practical applications are for the evaluation of breast asymmetries, both congenital and acquired, and for the evaluation of factors affecting breast shape in augmentation mammaplasty. Other uses of three-dimensional imaging that we have found clinically helpful are for evaluation of patients desiring reduction mammaplasty and for evaluation of patients undergoing unilateral breast reconstruction to determine the expander and permanent implant size that gives the best symmetry with the contralateral breast. We present five cases in which we investigate the use of three-dimensional imaging clinically by using the images to determine quantitative information about the breast, such as volume or projection. Overall, three-dimensional imaging is very helpful in providing objective information about the breast for use in preoperative planning. In addition, by analyzing clinical cases, it can provide objective data about the breast and surgical mammaplasty (especially augmentation mammaplasty) that may help surgeons better understand those factors that contribute to breast shape and influence surgical outcomes. There are currently some limitations of this system, influenced by patients with significant ptosis or obesity, which may introduce errors into the three-dimensional data, making them unreliable. However, we believe three-dimensional imaging has great clinical potential in surgical mammaplasty. 相似文献
39.
Synthesis of nucleotide analogues that potently and selectively inhibit human DNA primase 总被引:1,自引:0,他引:1
DNA primase synthesizes short RNA oligonucleotides that DNA polymerase alpha further elongates in order to initiate the synthesis of all new DNA strands during eukaryotic DNA replication. To develop potent and specific primase inhibitors, we combined 2'-modified sugars with bases incapable of normal Watson-Crick hydrogen bonding. The presence of a 2'-hydroxyl in either the ara or ribo configuration greatly enhances the ability of primase to polymerize a nucleotide. Further modifying the 2'-position by including both a hydroxyl and methyl group at this position greatly reduced the ability of primase to polymerize the resulting nucleotides. Replacing the base of the NTP with analogues incapable of normal Watson-Crick hydrogen bonding (benzimidazole, nitrobenzimidazole, and dichlorobenzimidazole) resulted in compounds that inhibited primase quite well and with similar potency. We synthesized arabinofuranosylbenzimidazole triphosphate (araBTP) and found that this sugar change increased inhibition by 2-4-fold relative to the ribofuranosyl analogue. AraBTP inhibited polymerization of both purines and pyrimidines, although primase polymerized only small amounts of the compound. Interestingly, even though araBTP was not readily polymerized by primase, it inhibited primase almost as potently as araATP, a compound that primase polymerizes extremely rapidly and that results in very strong chain termination. Importantly, this compound was a very weak inhibitor of and only slowly polymerized by DNA polymerase alpha, indicating that it is a specific primase inhibitor. The potential utility and mechanistic implications of these inhibitors are discussed. 相似文献
40.
Psammobatis extenta collected from the commercial bottom trawl fishery operating in Puerto Quequén, Argentina, between 2000 and 2001, had a sex ratio of 1:1 (535 specimens). Both the largest male and female measured 313 mm total length ( L T ). The relationship between total body mass and L T was significantly different between sexes; mature females weighed more than mature males for a given L T . The size at which 50% of males were sexually mature was 262 mm L T (83·6% of the maximum size), whereas 50% of females were mature at 249 mm L T (80·0% of the maximum size). The gonadosomatic index in mature males and females was slightly higher during summer, but did not show significant variation over the sampling period. The hepatosomatic index of males and females was higher during the autumn and winter and followed a distinct seasonal pattern. Evidence suggested a continuous reproductive cycle during the year, with a maximum number of females carrying egg-cases in summer. 相似文献