1
|
Ribeiro S, Ramos A, Brandão A, Rebelo JR, Guerra A, Resina C, Vila-Lobos A, Carvalho F, Remédio F, Ribeiro F. Cardiac valve calcification in haemodialysis patients: role of calcium-phosphate metabolism. Nephrol Dial Transplant 1998; 13:2037-40. [PMID: 9719161 DOI: 10.1093/ndt/13.8.2037] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Cardiac valve calcification (VC) has been detected with increased frequency in haemodialysis (HD) patients, making it necessary to determine the potential pathogenic factors in uraemic patients. METHODS A total of 92 chronic HD patients (39 female, 53 male) and 92 age and gender-matched nondialysis control subjects were evaluated by echocardiography and a severity score for VC was determined. Calcium phosphate metabolism was evaluated at the beginning of haemodialysis. RESULTS We found a greater prevalence of VC in dialysis patients than in normal patients (mitral annulus 44.5% vs 10%, P = 0.02; aortic annulus 52% vs 4.3%, P = 0.01). HD patients with mitral calcification were found to be older than patients without calcification, were on long-term renal replacement therapy, had longer duration of predialysis arterial hypertension, had greater values of the highest value of mean calcium phosphate product in 6 successive months (CaxP) and the highest absolute value of calcium-phosphate product (CaxPmax). We also found a positive correlation between calcification score, age, and CaxP. No correlation was found between actual VC and arterial hypertension or parathyroid hormone. Multiple stepwise regression analysis selected age and CaxP as the most predictive parameters for mitral calcification (r = 0.47). Mitral calcification was associated more frequently with rhythm and cardiac conduction defects, valvular insufficiency and with peripheral vascular calcification. Aortic calcification was correlated with age (r = 0.42) and longer duration of predialysis arterial hypertension. CONCLUSION Our study confirmed an increased prevalence of VC in HD patients and selected age and calcium phosphate product as the most predictive parameters. These findings support careful monitoring of calcium metabolism beginning at the early stages of end-stage renal failure to reduce the risk of heart disease.
Collapse
|
|
27 |
221 |
2
|
Schultz-Cherry S, Ribeiro S, Gentry L, Murphy-Ullrich JE. Thrombospondin binds and activates the small and large forms of latent transforming growth factor-beta in a chemically defined system. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)47086-x] [Citation(s) in RCA: 188] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
|
31 |
188 |
3
|
Abstract
When songbirds hear the song of another individual of the same species or when they sing, the mRNA levels of the ZENK gene increase rapidly in forebrain areas involved in vocal communication. This gene induction is thought to be related to long-term neuronal change and possibly the formation of song-related memories. We used immunocytochemistry to study the levels and distribution of ZENK protein in the brain of zebra finches and canaries after presentation of song playbacks. Birds that heard the playbacks and did not sing in response showed increased ZENK protein levels in auditory brain areas, including the caudomedial neostriatum and hyperstriatum ventrale, fields L1 and L3, the shelf adjacent to the high vocal center (HVC), the cup adjacent to the nucleus robustus archistriatalis (RA), and the nucleus mesencephalicus lateralis pars dorsalis (MLd). No ZENK expression was seen in song nuclei in these birds. Males that sang in response to the playbacks showed, in addition to auditory areas, increased ZENK protein in several song control nuclei, most prominently in HVC, RA, area X, and the dorsomedial nucleus (DN) of the intercollicular complex. The rise in ZENK protein followed that described previously for ZENK mRNA by a short lag, and the distribution of ZENK-labeled cells was in agreement with previous analysis of mRNA distribution. Thus, ZENK protein regulation can be used to assess activation of brain areas involved in perceptual and motor aspects of song. Possible implications of ZENK induction in these areas are discussed.
Collapse
|
|
27 |
182 |
4
|
Ribeiro S, Goyal V, Mello CV, Pavlides C. Brain gene expression during REM sleep depends on prior waking experience. Learn Mem 1999; 6:500-8. [PMID: 10541470 PMCID: PMC311304 DOI: 10.1101/lm.6.5.500] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/1999] [Accepted: 08/20/1999] [Indexed: 11/24/2022]
Abstract
In most mammalian species studied, two distinct and successive phases of sleep, slow wave (SW), and rapid eye movement (REM), can be recognized on the basis of their EEG profiles and associated behaviors. Both phases have been implicated in the offline sensorimotor processing of daytime events, but the molecular mechanisms remain elusive. We studied brain expression of the plasticity-associated immediate-early gene (IEG) zif-268 during SW and REM sleep in rats exposed to rich sensorimotor experience in the preceding waking period. Whereas nonexposed controls show generalized zif-268 down-regulation during SW and REM sleep, zif-268 is upregulated during REM sleep in the cerebral cortex and the hippocampus of exposed animals. We suggest that this phenomenon represents a window of increased neuronal plasticity during REM sleep that follows enriched waking experience.
Collapse
|
research-article |
26 |
156 |
5
|
Jarvis ED, Ribeiro S, da Silva ML, Ventura D, Vielliard J, Mello CV. Behaviourally driven gene expression reveals song nuclei in hummingbird brain. Nature 2000; 406:628-32. [PMID: 10949303 PMCID: PMC2531203 DOI: 10.1038/35020570] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hummingbirds have developed a wealth of intriguing features, such as backwards flight, ultraviolet vision, extremely high metabolic rates, nocturnal hibernation, high brain-to-body size ratio and a remarkable species-specific diversity of vocalizations. Like humans, they have also developed the rare trait of vocal learning, this being the ability to acquire vocalizations through imitation rather than instinct. Here we show, using behaviourally driven gene expression in freely ranging tropical animals, that the forebrain of hummingbirds contains seven discrete structures that are active during singing, providing the first anatomical and functional demonstration of vocal nuclei in hummingbirds. These structures are strikingly similar to seven forebrain regions that are involved in vocal learning and production in songbirds and parrots--the only other avian orders known to be vocal learners. This similarity is surprising, as songbirds, parrots and hummingbirds are thought to have evolved vocal learning and associated brain structures independently, and it indicates that strong constraints may influence the evolution of forebrain vocal nuclei.
Collapse
|
research-article |
25 |
153 |
6
|
Ribeiro S, Cecchi GA, Magnasco MO, Mello CV. Toward a song code: evidence for a syllabic representation in the canary brain. Neuron 1998; 21:359-71. [PMID: 9728917 DOI: 10.1016/s0896-6273(00)80545-0] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We show that presentation of individual canary song syllables results in distinct expression patterns of the immediate-early gene ZENK in the caudomedial neostriatum (NCM) of adult canaries. Information on the spatial distribution and labeling of stained cells provides for a classification of ZENK patterns that (1) accords to the organization of stimuli into families, (2) preserves the stimuli intrafamily relationships, and (3) confers salience to natural over artificial stimuli, resulting in a nonclassical tonotopic map. Moreover, complex syllable maps cannot be reduced to any linear combinations of simple syllable maps. These properties arise from the collective response of NCM neurons to auditory stimuli, rather than from the behavior of single neurons. The syllabic representation described here may constitute an important step toward deciphering the rules of birdsong auditory representation.
Collapse
|
|
27 |
126 |
7
|
Martins PM, Ribeiro S, Ribeiro C, Sencadas V, Gomes AC, Gama FM, Lanceros-Méndez S. Effect of poling state and morphology of piezoelectric poly(vinylidene fluoride) membranes for skeletal muscle tissue engineering. RSC Adv 2013. [DOI: 10.1039/c3ra43499k] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
|
12 |
110 |
8
|
Ribeiro S, Sousa JP, Nogueira AJ, Soares AM. Effect of endosulfan and parathion on energy reserves and physiological parameters of the terrestrial isopod Porcellio dilatatus. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2001; 49:131-138. [PMID: 11386726 DOI: 10.1006/eesa.2001.2045] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The in vivo effects of parathion and endosulfan on the isopod Porcellio dilatatus were investigated. Feeding parameters (food consumption and assimilation rates), growth, and energy reserves (glycogen, lipid, and protein contents) of pesticide-exposed isopods were compared with those of control animals. Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, and 500 microg/g of food) for 21 days. The route of uptake of the pesticides was through the diet (alder leaves). Results revealed that parathion induces a significant depression of glycogen, lipid, and protein contents. However, no significant effect was observed on either feeding parameters or growth. Animals fed endosulfan-contaminated food had smaller amounts of glycogen and lipid than control animals, while protein levels were similar in all treatments. Endosulfan also induced a significant decrease in food consumption and assimilation rates at the highest concentrations tested. Growth rate was also significantly affected by endosulfan. These results suggest that the isopod P. dilatatus is a suitable species for use in toxicity tests and that energy reserves could be used as effect criteria in both laboratory and field studies.
Collapse
|
|
24 |
100 |
9
|
Lipton RB, Lowenkopf T, Bajwa ZH, Leckie RS, Ribeiro S, Newman LC, Greenberg MA. Cardiac cephalgia: a treatable form of exertional headache. Neurology 1997; 49:813-6. [PMID: 9305346 DOI: 10.1212/wnl.49.3.813] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We report two patients with exertional headaches beginning with vigorous exercise and relieved by rest. Neurologic evaluation and neuroimaging were normal in both. During exercise stress testing, the onset of the patients' typical headaches correlated with ECG changes indicative of myocardial ischemia. In both patients coronary angiography revealed three-vessel disease, and myocardial revascularization procedures were followed by complete resolution of headaches. Based on these patients, and a review of prior similar reports, we conclude that myocardial ischemia is a rare and treatable cause of exertional headache. Accurate diagnosis is critical to controlling headaches and preventing myocardial infarction.
Collapse
|
Case Reports |
28 |
71 |
10
|
Abstract
The phylogenies for each of the protein-coding genes from the Methanococcus jannaschii genome were surveyed to determine the history of the major groups of life. For each gene, homologous sequences from other archaea, eucarya, and Gram-positive and Gram-negative bacteria were collected and aligned, and a phylogeny was reconstructed with a maximum-likelihood algorithm. The majority of significant phylogenies favor the eucarya and the archaca as sister groups. A smaller, but still substantial, portion of these significant phylogenies favor an eucarya/Gram-negative clade. These results indicate that support for the early history of life is not unequivocal. A chimeric origin of eukaryotes or an ancient, massive horizontal transfer of genes from Gram-negative bacteria to eucarya can explain many of the observed phylogenies.
Collapse
|
|
27 |
65 |
11
|
Vornlocher HP, Hanachi P, Ribeiro S, Hershey JW. A 110-kilodalton subunit of translation initiation factor eIF3 and an associated 135-kilodalton protein are encoded by the Saccharomyces cerevisiae TIF32 and TIF31 genes. J Biol Chem 1999; 274:16802-12. [PMID: 10358023 DOI: 10.1074/jbc.274.24.16802] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Translation initiation factor eIF3 is a multisubunit protein complex required for initiation of protein biosynthesis in eukaryotic cells. The complex promotes ribosome dissociation, the binding of the initiator methionyl-tRNA to the 40 S ribosomal subunit, and mRNA recruitment to the ribosome. In the yeast Saccharomyces cerevisiae eIF3 comprises up to 8 subunits. Using partial peptide sequences generated from proteins in purified eIF3, we cloned the TIF31 and TIF32 genes encoding 135- (p135) and 110-kDa (p110) proteins. Deletion/disruption of TIF31 results in no change in growth rate, whereas deletion of TIF32 is lethal. Depletion of p110 causes a severe reduction in cell growth and protein synthesis rates as well as runoff of ribosomes from polysomes, indicative of inhibition of the initiation phase. In addition, p110 depletion leads to p90 co-depletion, whereas other eIF3 subunit levels are not affected. Immunoprecipitation or nickel affinity chromatography from strains expressing (His)6-tagged p110 or p33 results in the co-purification of the well characterized p39 and p90 subunits of eIF3 as well as p110 and p33. This establishes p110 as an authentic subunit of eIF3. In similar experiments, p135 and other eIF3 subunits sometimes, but not always, co-purify, making assignment of p135 as an eIF3 subunit uncertain. Far Western blotting and two-hybrid analyses detect a direct interaction of p110 with p90, p135 with p33, and p33 with eIF4B. Our results, together with those from other laboratories, complete the cloning and characterization of all of the yeast eIF3 subunits.
Collapse
|
Comparative Study |
26 |
59 |
12
|
Ribeiro S, Sharma R, Gupta S, Cakar Z, De Geyter C, Agarwal A. Inter- and intra-laboratory standardization of TUNEL assay for assessment of sperm DNA fragmentation. Andrology 2017; 5:477-485. [PMID: 28245344 DOI: 10.1111/andr.12334] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 12/20/2022]
Abstract
One of the challenges with the sperm DNA fragmentation results is the inconsistency and the large variability in the results obtained by different techniques. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay quantifies the incorporation of fluoresceinated dUTP into single- and double-strand DNA breaks by labeling the 3'-OH terminal with TdT. The goal of this study was optimize the TUNEL protocol for assessment of sperm DNA fragmentation by standardization of the method and comparison of the data across two reference laboratories (i) at Basel, Switzerland and (ii) Cleveland Clinic, Ohio, USA. Semen samples from 31 subjects grouped into three cohorts. Sperm DNA fragmentation was data measured by two experienced operators at two different laboratories using identical semen samples, assay kit, protocol and acquisition settings using identical flow cytometers (BD Accuri C6). No significant differences were observed between the duplicates in any of the experiments performed. By including an additional washing step after fixation in paraformaldehyde, a high correlation was seen between the two laboratories (r = 0.94). A strong positive correlation was observed between the average sperm DNA fragmentation rates (r = 0.719). The mean sperm DNA fragmentation measured in each laboratory was similar. Both flow cytometers were identical in their settings and performance. This inter- and intra-laboratory study establishes that TUNEL is a reproducible assay when utilizing a standardized staining protocol and flow cytometer acquisition settings. Standardization and consensual guidelines for TUNEL validate the assay and establishes TUNEL as a robust test for measuring sperm DNA fragmentation especially in a multicenter setting.
Collapse
|
Research Support, Non-U.S. Gov't |
8 |
56 |
13
|
Santos J, Ribeiro S, Gaya A, Appell HJ, Duarte J. Skeletal Muscle Pathways of Contraction-Enhanced Glucose Uptake. Int J Sports Med 2008; 29:785-94. [PMID: 18401805 DOI: 10.1055/s-2008-1038404] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
|
17 |
49 |
14
|
Jarvis ED, Schwabl H, Ribeiro S, Mello CV. Brain gene regulation by territorial singing behavior in freely ranging songbirds. Neuroreport 1997; 8:2073-7. [PMID: 9223104 PMCID: PMC2528959 DOI: 10.1097/00001756-199705260-00052] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To investigate the ecological relevance of brain gene regulation associated with singing behavior in songbirds, we challenged freely ranging song sparrows with conspecific song playbacks within their breeding territories. Males responded by approaching the speaker, searching for an intruder and actively singing. In situ hybridization of brain sections revealed significantly higher expression of the transcriptional regulator ZENK in challenged birds than in unstimulated controls in several auditory structures and song control nuclei. We conclude that singing behavior in the context of territorial defense is associated with gene regulation in brain centers that control song perception and production, and that behaviorally regulated gene expression can be used to investigate brain areas involved in the natural behaviors of freely ranging animals.
Collapse
|
research-article |
28 |
48 |
15
|
Millard JT, Weidner MF, Kirchner JJ, Ribeiro S, Hopkins PB. Sequence preferences of DNA interstrand crosslinking agents: quantitation of interstrand crosslink locations in DNA duplex fragments containing multiple crosslinkable sites. Nucleic Acids Res 1991; 19:1885-91. [PMID: 1903204 PMCID: PMC328119 DOI: 10.1093/nar/19.8.1885] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A general approach to the quantitative study of the sequence specificity of DNA interstrand crosslinking agents in synthetic duplex DNA fragments is described. In the first step, a DNA fragment previously treated with an interstrand crosslinking agent is subjected to denaturing PAGE. Not only does this distinguish crosslinked from native or monoadducted DNA, it is shown herein that isomeric crosslinked DNAs differing in position of the crosslink can in some cases be separated. In the second stage, the now fractionated crosslinked DNAs isolated from denaturing PAGE are subjected to fragmentation using iron(II)/EDTA. For those fractions which are structurally homogeneous, analysis of the resulting fragment distribution has previously been shown to reveal the crosslink position at nucleotide resolution. It is shown herein that in fractions which are structurally heterogeneous due to differences in position of crosslink, this analysis quantifies the relative extent of crosslinking at distinct sites. Using this method it is shown that reductively activated mitomycin C crosslinks the duplex sequences 5'-GCGC and 5'-TCGA with 3 +/- 1:1 relative efficiency.
Collapse
|
research-article |
34 |
47 |
16
|
Ribeiro S, Reich H, Rosenberg J, Guglielminetti E, Vidali A. The value of intra-operative cystoscopy at the time of laparoscopic hysterectomy. Hum Reprod 1999; 14:1727-9. [PMID: 10402376 DOI: 10.1093/humrep/14.7.1727] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to determine the usefulness of routine intra-operative cystoscopy in documenting ureteral injury during total laparoscopic hysterectomy with vault suspension and to document the incidence of this complication in a large series. The charts of 118 patients who underwent laparoscopic hysterectomy with vault suspension from January 1992 to January 1998 were retrospectively reviewed. The patients underwent intra-operative cystoscopic evaluation to verify ureteral permeability and bladder integrity. Intra-operative ureteral obstruction occurred in four patients (3.4%). All complications were immediately fixed and there were no postoperative ureteral problems. No late ureteral complications were observed. Intra-operative cystoscopy allows for early recognition and treatment of obstructive ureteral injuries and may reduce the rate of late postoperative complications during advanced laparoscopic procedures.
Collapse
|
|
26 |
44 |
17
|
Zeidler W, Egle C, Ribeiro S, Wagner A, Katunin V, Kreutzer R, Rodnina M, Wintermeyer W, Sprinzl M. Site-directed mutagenesis of Thermus thermophilus elongation factor Tu. Replacement of His85, Asp81 and Arg300. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 229:596-604. [PMID: 7758452 DOI: 10.1111/j.1432-1033.1995.tb20503.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
His85 in Thermus thermophilus elongation factor Tu (EF-Tu) was replaced by glutamine, leucine and glycine residues, leading to [H85Q]EF-Tu, [H85L] EF-Tu and [H85G]EF-Tu, respectively. Asp81 was replaced by alanine leading to [D81A]EF-Tu, and replacement of Arg300 provided [R300I]EF-Tu. Glycine in position 85 of domain I induces a protease-sensitive site in domain II and causes complete protein degradation in vivo. A similar effect was observed when Asp81 was replaced by alanine or Arg300 by isoleucine. Degradation is probably due to disturbed interactions between the domains of EF-Tu.GTP, inducing a protease-sensitive cleavage site in domain II. [H85Q]EF-Tu, which can be effectively overproduced in Escherichia coli, is slower in poly(U)-dependent poly(Phe) synthesis, has lower affinity to aminoacyl-tRNA but shows only a slightly reduced rate of intrinsic GTP hydrolysis compared to the native protein. The GTPase of this protein variant is not efficiently stimulated by aminoacyl-tRNA and ribosomes. The slow GTPase of [H85Q]EF-Tu increases the fidelity of translation as measured by leucine incorporation into poly(Phe) in in vitro poly(U)-dependent ribosomal translation. Replacement of His85 in T. thermophilus EF-Tu by leucine completely deactivates the GTPase activity but does not substantially influence the aminoacyl-tRNA binding. [H85L]EF-Tu is inactive in poly(U)-dependent poly(Phe)-synthesis. The rate of nucleotide dissociation is highest for [H85L]EF-Tu, followed by [H85Q]EF-Tu and native T. thermophilus EF-Tu. Mutation of His85, a residue which is not directly involved in the nucleotide binding, thus influences the interaction of EF-Tu domains, nucleotide binding and the efficiency and rate of GTPase activity.
Collapse
|
|
30 |
42 |
18
|
Ribeiro S, Guilhermino L, Sousa JP, Soares AM. Novel bioassay based on acetylcholinesterase and lactate dehydrogenase activities to evaluate the toxicity of chemicals to soil isopods. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 1999; 44:287-293. [PMID: 10581123 DOI: 10.1006/eesa.1999.1837] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study developed a bioassay with the isopod Porcellio dilatatus based on the activity of the enzymes acetylcholinesterase (AChE) and lactate dehydrogenase (LDH). The in vivo effects of the insecticides parathion-ethyl and endosulfan-sulfate on AChE and LDH activities of P. dilatatus under laboratory conditions were investigated. The route of uptake of the pesticides was through the food (alder leaves). Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, and 500 microg/g of food) for 21 days. After this period, the activity of AChE and LDH was determined. Parathion induced significant depression of both AChE and LDH activities. Animals fed with endosulfan-contaminated food exhibited lower LDH activities than control animals, while AChE activity was similar in all treatments. The results of the present investigation suggest that the isopod. P. dilatatus is a suitable species for use in toxicity tests and indicate that the enzymes AChE and LDH could be used as effect criteria both in laboratory and in field studies with this species.
Collapse
|
|
26 |
41 |
19
|
Ribeiro S, Gomes AC, Etxebarria I, Lanceros-Méndez S, Ribeiro C. Electroactive biomaterial surface engineering effects on muscle cells differentiation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 92:868-874. [PMID: 30184816 DOI: 10.1016/j.msec.2018.07.044] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 06/27/2018] [Accepted: 07/18/2018] [Indexed: 01/15/2023]
Abstract
Even though skeletal muscle cells can naturally regenerate as a response to insignificant tissue damages, more severe injuries can cause irreversible loss of muscle cells mass and/or function. Until now, cell therapies are not a good approach to treat those injuries. Biomaterials such as poly(vinylidene fluoride), PVDF, can improve muscle regeneration by presenting physical cues to muscle cells that mimic the natural regeneration environment. In this way, the ferroelectric and piezoelectric properties of PVDF offer new opportunities for skeletal muscle tissue engineering once the piezoelectricity is an electromechanical effect that can be used to provide electrical signals to the cells, upon mechanical solicitations, similar to the ones found in several body tissues. Thus, previous to dynamic experiments, it is important to determine how the surface properties of the material, both in terms of the poling state (positive or negative net surface charge) and of the morphology (films or fibers) influence myoblast differentiation. It was observed that PVDF promotes myogenic differentiation of C2C12 cells as evidenced by quantitative analysis of myotube fusion, maturation index, length, diameter and number. Charged surfaces improve the fusion of muscle cells into differentiated myotubes, as demonstrated by fusion and maturation index values higher than the control samples. Finally, the use of random and oriented β-PVDF electrospun fibers scaffolds has revealed differences in cell morphology. Contrary to the randomly oriented fibers, oriented PVDF electrospun fibers have promoted the alignment of the cells. It is thus demonstrated that the use of this electroactive polymer represents a suitable approach for the development of electroactive microenvironments for effective muscle tissue engineering.
Collapse
|
Journal Article |
7 |
41 |
20
|
Lopes T, Dias JS, Marcelino J, Varela J, Ribeiro S, Dias J. An assessment of the clinical efficacy of intranasal desmopressin spray in the treatment of renal colic. BJU Int 2001; 87:322-5. [PMID: 11251523 DOI: 10.1046/j.1464-410x.2001.00068.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To assess the efficacy of desmopressin nasal spray compared with diclofenac given intramuscularly in patients with acute renal colic caused by urolithiasis. PATIENTS AND METHODS The study included 61 patients randomized into three different groups; group A received desmopressin (40 microg, nasal spray), group B diclofenac (75 mg) intramuscularly and group C, both desmopressin and diclofenac. Pain was assessed using a visual analogue scale (a 10-cm horizontal scale ranging from 'no pain' to 'unbearable pain') at baseline, 10, 20 and 30 min after administering the treatments. RESULTS On admission, the pain level was the same in all three groups. At 10 min the pain decreased in all groups to a level that was not significantly different. At 20 min groups B and C had similar mean pain levels (3.7), whereas in group A it was 5.0. At 30 min, groups B and C scored 2-3, and group A 5.6. All three treatments were equally effective at 10 and 20 min but at 30 min there was a stabilization/slight increase in pain level in group A. CONCLUSIONS Desmopressin has several advantages, e.g. ease of administration, simplicity of delivery and apparent lack of side-effects, which makes it suitable for ambulatory use. Desmopressin acts rapidly and seems to be effective in both single and combined therapy with diclofenac; it decreases the need for a second treatment and increases the analgesic effect of diclofenac. Some patients responded well to desmopressin, with rapid and complete pain relief. These results indicate that desmopressin may be used to treat renal colic either alone or combined, increasing the analgesic effect of other drugs. More studies are needed to validate and confirm the results; it would also be useful to determine factors that may identify the subgroup of patients who respond quickly and with almost complete pain relief.
Collapse
|
Clinical Trial |
24 |
38 |
21
|
Ribeiro S, Nock S, Sprinzl M. Purification of aminoacyl-tRNA by affinity chromatography on immobilized Thermus thermophilus EF-Tu.GTP. Anal Biochem 1995; 228:330-5. [PMID: 8572315 DOI: 10.1006/abio.1995.1359] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Elongation factor Tu from Thermus thermophilus containing six histidine residues on its C-terminus, EF-Tu(CHis6), was used for purification of aminoacyl-tRNA isoacceptors, from aminoacylated bulk tRNA, by affinity chromatography. Preformed aminoacyl-tRNA.EF-Tu(CHis6).GTP ternary complexes were immobilized on Ni(2+)-nitriloacetic acid agarose and the aminoacyl-tRNA was eluted at high ionic strength or with buffers containing GDP. Compared to alternative methods, the reported immobilization by C-terminal histidine residues does not lead to loss of EF-Tu's affinity for aminoacyl-tRNA. The method is well suited for preparative isolation of aminoacylated tRNA isoacceptors and as an analytical tool to test tRNA composition and aminoacylation of tRNA in crude cellular extracts.
Collapse
|
|
30 |
36 |
22
|
Rudinger J, Blechschmidt B, Ribeiro S, Sprinzl M. Minimalist aminoacylated RNAs as efficient substrates for elongation factor Tu. Biochemistry 1994; 33:5682-8. [PMID: 8180193 DOI: 10.1021/bi00185a003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We demonstrate here, using RNA variants derived from tRNAAsp, that the minimalist aminoacylated structure able to interact efficiently with elongation factor Tu comprises a 10 base-pair helix linked to the 3'-terminal NCCA sequence. Shorter structures can interact with the elongation factor, but with significantly decreased affinity. Conserved features in the aminoacyl acceptor branch of tRNAs, such as base pair G53-C61 and the T-loop architecture, could be replaced respectively by the inverted base pair C53-G61 and by unusual anticodon loop or tetraloop sequences. Variants of whole tRNAAsp or of the 12 base-pair aspartate minihelix, with enlarged 13 base-pair long aminoacyl acceptor branches, as in selenocysteine-inserting tRNAs that are not recognized by elongation factor Tu, keep their binding ability to this factor. These functional results are well accounted for by the crystallographic structure of the Thermus thermophilus binary EF-Tu.GTP complex, which possesses a binding cleft accommodating the minimalist 10 base-pair domain of the tRNA aminoacyl acceptor branch.
Collapse
|
|
31 |
35 |
23
|
Ribeiro S, Mello CV. Gene expression and synaptic plasticity in the auditory forebrain of songbirds. Learn Mem 2000; 7:235-43. [PMID: 11040254 DOI: 10.1101/lm.34400] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
Review |
25 |
33 |
24
|
|
|
25 |
31 |
25
|
Nock S, Grillenbeck N, Ahmadian MR, Ribeiro S, Kreutzer R, Sprinzl M. Properties of isolated domains of the elongation factor Tu from Thermus thermophilus HB8. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 234:132-9. [PMID: 8529632 DOI: 10.1111/j.1432-1033.1995.00132.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The relative contributions of the three domains of elongation factor Tu (EF-Tu) to the factor's function and thermal stability were established by dissecting the domains apart with recombination techniques. Domain I (EF-TuI), domains I/II (EF-TuI/II) and domain III (EF-TuIII) of the EF-Tu from Thermus thermophilus HB8 comprising the amino acids 1-211, 1-312 and 317-405, respectively, were overproduced in Escherichia coli and purified. A polypeptide consisting of domain II and III (EF-TuII/III) was prepared by limited proteolysis of native EF-Tu with V8 protease from Staphylococcus aureus [Peter, M. E., Reiser, C. O. A., Schirmer, N. K., Kiefhaber, T., Ott, G., Grillenbeck, N. W. & Sprinzl, M. (1990) Nucleic Acids Res. 18, 6889-6893]. As determined by circular dichroism spectrometry, the isolated domains have the secondary structure elements found in the native EF-Tu. GTP and GDP binding as well as GTPase activity are maintained by the EF-TuI and EF-TuI/II; however, the rate of GDP dissociation from EF-TuI . GDP and EF-TuI/II . GDP complex is increased as compared to native EF-Tu . GDP, reflecting a constraint imposed by domain III on the ability to release the nucleotide from its binding pocket located in domain I. A weak interaction of Tyr-tRNATyr with the EF-TuI . GTP suggests that domain I provides a part of the structure interacting with aminoacyl-tRNA. The domain III is capable of regulating the rate of GTPase in EF-Tu, since the polypeptide consisting only of domains I/II has a 39-fold higher intrinsic GTPase compared to the native EF-Tu. No in vitro poly(U)-dependent poly(Phe) synthesis was detectable with a mixture of equimolar amounts of domains I/II and domain III, demonstrating the necessity of covalent linkage between the domains of EF-Tu for polypeptide synthesis. In contrast to native EF-Tu and EF-TuII/III, EF-TuI and, to a lesser extent the polypeptide consisting of domains I/II, are unstable at elevated temperatures. This indicates that domains II/III strongly contribute to the thermal stability of this T. thermophilus EF-Tu. Deletion of amino acid residues 181-190 from domain I of T. thermophilus EF-Tu decreases the thermostability to that of EF-Tu from E. coli, which does not have these residues. Interdomain interactions must be important for the stabilisation of the structure of domain I, since isolated T. thermophilus EF-TuI is thermolabile despite the presence of the 181-190 loop.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
|
30 |
29 |