Search PubMed⌕ Search

Biomedical subjects

C Morera

Publications and source records attributed to C Morera.

At least 19 recordsLinked to original sources
PubMed2006

[Analysis of the cochlear implant as a treatment technique for profound hearing loss in pre and postlocutive patients].

INTRODUCTION: These are the objectives planned for this study: 1. Evaluate the results from the communication point of view. 2. Evaluate the cochlear implant (CI) impact on the quality of life. 3. Evaluate medical complications and technical failures. 4. Assess direct and indirect costs generated during the phases of a cochlear implantation programme. 5. Determine which factors have a high impact on the clinical evolution and the financial cost. MATERIALS AND METHOD: A population of 877 patients, postlingual and prelingual, adults and children, have been studied. They were treated in 5 Spanish centres with cochlear implant programmes. Audiometric tests and global questionnaires on life quality have been carried out. Medical and CI technology complications have also been computed. Direct and indirect economic costs of a cochlear implant have been calculated. RESULTS: Postlocutive-implanted patients reached the 40 dB SPL threshold in the Pure Tone Audiometry, and this result was maintained during the 12-year evolution. In Vowels test, it evolved from a 30% on pre-stimulation to 80-90%, in Disyllables words test it evolved from a 10% to a 50-60%, and in CID Sentences test it evolved from an 18% to a 60-70%. In the prelocutive population, results were influenced by the child's age at implantation. The best results were obtained by the children who had been implanted earlier. Those implanted between 0 and 3 years old evolved in the Vowels test from 0% during pre-stimulation to 95%, from a 0% to a 90% in Disyllables words test and from a 0% to a 90-95% in CID Sentences test. Also, the speech acquisition and development of the pre-locutive population was also influenced by the implantation age. An 80% of postlocutive adult patients stated a mood and sociability improvement after the cochlear implantation. They did not show health changes in general nor relevant modifications in the attention they usually received from relatives and friends. Severe medical-surgical complications were registered for a 3.42% of the cases, a 7.06% of mild medical-surgical complications and a 3.07% of technical breakdowns in the internal components of the CI. Financial cost of implantation for a post-locutive adult oscillated between 36,912 Euro and 37,048 Euro, and between 37,689 Euro and 44,273 Euro for a pre-locutive child. CONCLUSIONS: Cochlear implants clearly enhance communication skills of the implantees. Results obtained for the prelocutive implanted population justify the creation of hearing screening programmes in new-borns. Postlocutive implanted adults have expressed satisfaction for the results obtained. However, they did perceive some limitations in situations of unfavourable acoustic conditions. An analysis of direct and indirect costs related to a CI programme has been made. It may be useful to carry out reports on the cost-benefit ratio in this field. The low index of complications observed shows which cochlear implant treatment technique complies with the adequate safety margins. The factors influencing the most in the evolution are: duration of hearing deprivation, age at implantation, cochlear anatomy and functionality of the auditory pathway, patient's and relative's motivation, and the coexistence of other handicaps associated to hearing losses.

Adolescent↗
PubMed2005

Advantages of binaural hearing provided through bimodal stimulation via a cochlear implant and a conventional hearing aid: a 6-month comparative study.

CONCLUSIONS: Our study data demonstrate the additional benefit derived from continued use of a contralateral hearing aid (HA) post-cochlear implantation for speech recognition ability in quiet and in noise. Postoperative bimodal stimulation is recommended for all subjects who show some speech recognition ability in the contralateral ear as it may offer binaural listening advantages in various listening situations encountered in everyday life. OBJECTIVES: To assess the benefits derived from bimodal stimulation for experienced HA users implanted with a cochlear implant (CI) (score=20% in disyllabic test). The correlation between pre- and postoperative performance on speech perception measures was examined to determine additional criteria for recommending bimodal stimulation postoperatively. MATERIAL AND METHODS: A within-subject repeated-measures design was used, with each subject acting as their own control. Assessments were carried out preoperatively in aided monaural and best-aided conditions and at 6 months postoperatively in CI-alone, contralateral HA-alone and bimodal listening conditions. Speech recognition using Spanish words and sentences materials was assessed at conversational level and for soft speech in quiet. Speech comprehension in noise was assessed using word materials at a signal:noise ratio of +10, for coincident speech in noise and for spatially separated speech in noise. Twelve adult native Spanish subjects with a severe-to-profound hearing impairment who were experienced with optimally fitted conventional amplification and who displayed suboptimal speech understanding preoperatively were enrolled in the study. Preoperatively, conventional amplification was worn by five subjects binaurally and by seven monaurally. RESULTS: Postoperatively, superior speech recognition ability in quiet and in noise for disyllabic words was achieved using bimodal stimulation in comparison to performance for either monaural aided condition. Mean improvement in speech recognition in the bimodal condition was significant over performance in the CI-alone condition for disyllabic words in quiet at 70 (p=0.006) and 55 dB SPL (p=0.028), for disyllabic words in noise at +10 dB with speech and noise spatially separated with the noise source closest to the contralateral HA (S0NHA) (p=0.0005) and when the noise source was closest to the CI ear (S0NCI) (p=0.002). When testing word recognition in noise with speech and noise sources coincident in space, word scores were superior in the bimodal condition relative to the CI-alone condition but this improvement was not significant (p=0.07). The advantages of bimodal stimulation included significant effects of binaural summation in quiet and significant binaural squelch effects in both the S0NHA and S0NCI test conditions. All subjects showed superior performance in the binaural situation postoperatively relative to the best-aided condition preoperatively for one or more test situations.

Adult↗
PubMed2004

[Speech understanding in post-lingual adults with cochlear implants].

It is well recognised that multi-channel cochlear implants are highly effective in gaining or regaining auditory perceptual skills of severe to profound hearing-impaired people. Research shows that adults rapidly improve in speech understanding after cochlear implantation. This study reports on speech understanding from two Spanish Clinics. 32 post-lingually deafened adults were fitted with either a MED-EL COMBI 40 or COMBI 40+ cochlear implant at the Hospital Universitario San Cecilio, at the Granada or Hospital Universitario La Fe, Valencia Clinic, Spain. Subjects were assessed at 1, 3, 6 and 12 months post-fitting on a number of speech perception tests. Results showed a highly significant improvement on all speech perception tests over the time. These ratify other studies in saying that cochlear implantation is a viable and successful treatment in post-lingually deafened adults.

Adult↗
PubMed2002

Expression of p53 protein and tumor angiogenesis as prognostic factors in nasopharyngeal carcinoma patients.

The objective of this study was to evaluate the possible prognostic significance of p53 protein overexpression and tumor angiogenesis (TA) in nasopharyngeal carcinoma (NPC) patients, together with other clinicopathological variables. Forty-two NPC patients were evaluated in relation to survival. Nuclear p53 overexpression in neoplastic and endothelial cells was detected by immunohistochemistry (IHC) with the monoclonal antibody DO-7 and the polyclonal antibody against factor VIII-related antigen, respectively. Thereafter, we evaluated p53 cases in order to determine their nuclear immunoreactivity from negative (-) to positive (+, ++, +++). In addition, microvessels were counted in the most active areas of tumor neovascularization or hotspots using an image computer analyzer (MicroImage). A Cox multiple regression survival analysis was used to determine the best prognostic indicators in NPC patients. As a result, tumor microvessel count, considered as a continuous variable, was the most important independent prognostic indicator in relation to survival (p = 0.0273), with a relative risk of death of 2,4399 [95% confidence interval = 1.1051 ; 5.3871] associated with the highest microvessel counts. Moreover, the only clinicopathological variable that demonstrated prognostic value in a Cox multiple regression survival analysis was histological type (p = 0.05). In addition, we did not observe any statistical association between intratumoral microvessel density (IMD), clinicopathological variables and p53 protein expression.

Biomarkers, Tumor↗
PubMed2001

A purine-related metabolite negatively regulates fixNOQP expression in Sinorhizobium meliloti by modulation of fixK expression.

5-aminoimidazole-4-carboxamide nucleotide (AICAR) is a negative effector of cytochrome terminal oxidase cbb3 production in Rhizobium etli. In this work, the effect of AICAriboside (AICAr), the precursor of AICAR on the expression of the Sinorhizobium meliloti fixNOQP operon encoding the symbiotic terminal oxidase cbb3, was analyzed. AICAr reduced the microaerobic induction levels of fixN-lacZ and fixT-lacZ gene fusions 18- and seven-fold respectively, and both genes were activated by the transcriptional activator FixK. A fixK-lacZ fusion presented 14-fold-reduced induction levels in microaerobic cell cultures in the presence of AICAr. AICAr also reduced three-fold the microaerobic expression levels of the nifA-lacZ fusion, whose expression as well as that of fixK is controlled by the two-component system FixL-FixJ. In contrast, AICAr had no effect on the expression levels of a hemA-lacZ fusion. These data suggest that AICAr prevents fixNOQP induction by the inhibition of fixK transcription.

Aminoimidazole Carboxamide↗
PubMed2001

Regulation of gene expression in response to oxygen in Rhizobium etli: role of FnrN in fixNOQP expression and in symbiotic nitrogen fixation.

Previously, we reported finding duplicated fixNOQP operons in Rhizobium etli CFN42. One of these duplicated operons is located in the symbiotic plasmid (fixNOQPd), while the other is located in a cryptic plasmid (fixNOQPf). Although a novel FixL-FixKf regulatory cascade participates in microaerobic expression of both fixNOQP duplicated operons, we found that a mutation in fixL eliminates fixNOQPf expression but has only a moderate effect on expression of fixNOQPd. This suggests that there are differential regulatory controls. Interestingly, only the fixNOQPd operon was essential for symbiotic nitrogen fixation (L. Girard, S. Brom, A. Dávalos, O. Lopez, M. Soberón, and D. Romero, Mol. Plant-Microbe Interact. 13:1283-1292, 2000). Searching for potential candidates responsible for the differential expression, we characterized two fnrN homologs (encoding transcriptional activators of the cyclic AMP receptor protein [CRP]-Fnr family) in R. etli CFN42. One of these genes (fnrNd) is located on the symbiotic plasmid, while the other (fnrNchr) is located on the chromosome. Analysis of the expression of the fnrN genes using transcriptional fusions with lacZ showed that the two fnrN genes are differentially regulated, since only fnrNd is expressed in microaerobic cultures of the wild-type strain while fnrNchr is negatively controlled by FixL. Mutagenesis of the two fnrN genes showed that both genes participate, in conjunction with FixL-FixKf, in the microaerobic induction of the fixNOQPd operon. Participation of these genes is also seen during the symbiotic process, in which mutations in fnrNd and fnrNchr, either singly or in combination, lead to reductions in nitrogen fixation. Therefore, R. etli employs a regulatory circuit for induction of the fixNOQPd operon that involves at least three transcriptional regulators of the CRP-Fnr family. This regulatory circuit may be important for ensuring optimal production of the cbb(3), terminal oxidase during symbiosis.

Amino Acid Sequence↗
PubMed2000

Expression pattern of Rhizobium etli ccmIEFH genes involved in c-type cytochrome maturation.

In different bacterial species, ccmIEFH genes have been suggested to code for subunits of a bacterial haem-lyase catalyzing the covalent attachment of haem to c-type apoproteins. In Rhizobium etli CE3 there are two copies of ccmIEFH: one in the chromosome and the other located in plasmid pf. However, the null phenotype of chromosomal ccmF mutant indicates that the gene locus of plasmid pf is not functional. Two ccmI chromosomal mutants, previously isolated, produced detectable levels of c-type cytochromes under certain culture conditions in contrast with the ccmF mutant, suggesting that ccmF could be transcribed independently. The transcriptional organization of ccmIEFH operon was established. Two promoters from the chromosomal locus were mapped by primer extension, one located upstream of ccmI and the second located upstream of ccmF. The regulation of the expression of both promoters was studied using appropriate lacZ gene fusions (ccmI-lacZ and ccmEF-lacZ). The ccmI-lacZ gene fusion was expressed in complex medium, during exponential growth, under microaerobic conditions and in a R. etli mutant that accumulates reducing power, conditions where a higher respiration rate could be limited by c-type cytochrome content. The ccmEF-lacZ fusion was also primarily expressed in complex medium and under microaerophilic conditions. The finding of two independent promoters in this gene locus could suggest that the step catalyzed by CcmFH could be a rate-limiting step for c-type cytochrome assembly under certain culture conditions.

Amino Acid Sequence↗
PubMed2000

Morphometric study of tumor angiogenesis as a new prognostic factor in nasopharyngeal carcinoma patients.

The aim of this study was to determine the possible prognostic significance of tumor angiogenesis (TA) in nasopharyngeal carcinoma (NPC) patients. Fifty-five NPC patients were evaluated in relation to survival. Endothelial cells were immunohistochemically stained with anti-von Willebrand factor (F-VIII), CD-31 and CD-34 antibodies, and microvessels counted in the most active areas of tumor neovascularization or hotspotsusing both a manual and an automatic method. Overall survival analysis calculated by the Kaplan Meiertest revealed that both methods were correlated with a statistical significance between intratumoral microvessel density (IMD) and overall survival, using either manual (p=0.0141) or automatic counting (p=0.0117). Other angiogenic parameters studied were perimeter, roundness and accumulative area of the microvessels using a morphometric analyzer. Moreover, our results show that cases with high IMD demonstrated a prognostic significance in relation to the accumulative area (p=0.0072).

Adult↗
PubMed1999

Normal and anomalous pancreaticobiliary union in children and adolescents.

BACKGROUND: The normal length of the pancreaticobiliary union (common channel) in the pediatric population is not known, nor is the frequency of anomalous pancreaticobiliary union and the extent to which it is associated with pancreaticobiliary disease. METHODS: ERCP was performed on 136 patients younger than 1 year (group 1) and 128 older than 1 year (group 2). RESULTS: In group 1 the average length of the common channel was 1.8 +/- 0.61 mm with a maximal length of 3 mm (mean plus 2 standard deviations). In group 2 the average length and maximal length of the common channel increased with age. In the 1 to 3 year age range the average length was 2.2 +/- 0.47 mm with a maximal length of 2.7 mm, in the 4 to 6 year range it was 2.8 +/- 0.40 mm (3.6 mm maximal), in the 7 to 9 year range it was 3.2 +/- 0.43 mm (4.1 mm maximal), in the 10 to 12 year range it was 3.9 +/- 0.5 mm (4.4 mm maximal), and in the 13 to 15 year range it was 4.0 +/- 0.51 mm (5 mm maximal). The prevalence of the anomalous pancreaticobiliary union was 25% (66/264). In group 1 the anomaly was present in 4.4% (6 of 136) of patients, 1.3% (1/76) with neonatal hepatitis, 4.6% (3/44) with biliary atresia, and 100% (2/2) with choledochal cyst. In group 2 the anomaly was present in 46.9% (60/128) of patients, 100% (57/57) with choledochal cyst and 15.7% (3/19) with idiopathic recurrent pancreatitis without bile duct dilatation. CONCLUSIONS: The mean length of the common channel increases with age. The maximum normal length of the common channel in neonates and infants younger than 1 year is 3 mm. It increases with age to a maximum of 5 mm in children and adolescents between 13 and 15 years of age. Anomalous pancreaticobiliary union is relatively common among children and adolescents undergoing ERCP in our center, including those with idiopathic recurrent pancreatitis (15.7%). ERCP is valuable in the diagnosis of this anomaly.

Adolescent↗
PubMed1999

Sphincter of Oddi dysfunction in children with recurrent pancreatitis and anomalous pancreaticobiliary union: an etiologic concept.

BACKGROUND: The exact cause of recurrent pancreatitis among patients with anomalous pancreaticobiliary union is not known. Sphincter of Oddi dysfunction has been implicated as a mechanism. This study evaluated sphincter of Oddi function in children with anomalous pancreaticobiliary union and recurrent pancreatitis and assessed the results of endoscopic sphincterotomy in the management of this condition. METHODS: We retrospectively reviewed 128 endoscopic retrograde cholangiopancreatographic (ERCP) studies performed on children older than 1 year and adolescents with pancreaticobiliary disease. In 64 instances, ERCP was performed because of recurrent pancreatitis. Nine patients underwent sphincter of Oddi manometry followed by endoscopic sphincterotomy, and these patients were included in this study. A basal pressure greater than 35 mm Hg was considered diagnostic for sphincter of Oddi dysfunction. Follow-up data were obtained retrospectively from the patients' relatives and referring physicians. RESULTS: An anomalous pancreaticobiliary union was found in 18 of 64 (28%) patients with recurrent pancreatitis. The 9 patients who underwent sphincter manometry and endoscopic sphincterotomy were 5 girls and 4 boys 2.9 to 17 years of age (mean 7.8 years). A choledochal cyst was found in 7 of these 9 patients. Two patients had anomalous pancreaticobiliary union without common bile duct dilatation. All 9 patients had sphincter of Oddi dysfunction (mean basal pressure 96 +/- 37.8 mm Hg, range 48 to 156 mm Hg). The length of the common channel was 22.8 +/- 5.5 mm, and the length of the sphincter of Oddi segment was 12.1 +/- 1.9 mm (p < 0.001). In all patients the sphincter of Oddi segment was located within the duodenal wall. The mean follow-up period after endoscopic sphincterotomy was 26.4 months (range 18 to 38 months). Eight patients had excellent results defined as absence of symptoms and no subsequent episodes of acute pancreatitis. Treatment of 1 patient was considered moderately successful because the patient still had occasional pain without pancreatic enzyme elevation but no subsequent episodes of acute pancreatitis. One patient had mild postprocedural pancreatitis. CONCLUSIONS: Recurrent pancreatitis and anomalous pancreaticobiliary union are associated with sphincter of Oddi dysfunction in children and adolescents. Endoscopic sphincterotomy is beneficial to these patients.

Adolescent↗
PubMed1999

Enhanced nitrogen fixation in a rhizobium etli ntrC mutant that overproduces the bradyrhizobium japonicum symbiotic terminal oxidase cbb3

The ntrC gene codes for a transcriptional activator protein that modulates gene expression in response to nitrogen. The cytochrome production pattern of a Rhizobium etli ntrC mutant (CFN2012) was studied. CO difference spectral analysis of membranes showed that CFN2012 produced a terminal oxidase similar to the symbiotic terminal oxidase of bacteroids in free-living cells under aerobic conditions, with a characteristic trough at 553 nm. CFN2012 produced two c-type cytochromes with molecular masses of 27 and 32 kDa, in contrast with the wild-type strain, which produced only a 32-kDa c-type cytochrome. The expression levels of the R. etli fixNOQP operon, which codes for terminal oxidase cbb3, were not affected by the ntrC mutation. However, the production levels of the two c-type cytochromes (27 and 32 kDa) were enhanced at least eightfold when the Bradyrhizobium japonicum fixNOQP operon was expressed in CFN2012 from the nptII promoter (pMSfixc), suggesting that these proteins are subunits FixO (27 kDa) and FixP (32 kDa) of cbb3 and that CFN2012/pMSfixc overproduced this terminal oxidase. CFN2012/pMSfixc showed a significant increase in its symbiotic performance as judged by the determination of nitrogenase activities of plants inoculated with this strain, suggesting that the overproduction of cbb3 terminal oxidase correlates with an enhancement in symbiotic nitrogen fixation.

Journal Article↗
PubMed1998

Isolation of Sinorhizobium meliloti Tn5 mutants with altered cytochrome terminal oxidase expression and improved symbiotic performance.

The relationship between whole-cell redox potential, cytochrome composition in free-living culture and symbiotic activity of Sinorhizobium meliloti was studied. Three Tn5-induced mutants with increased cellular redox potential were generated. Stationary cultures of mutants Tb9 and Tb16 in contrast to the parental strain produced the b-type terminal oxidase that may be similar to the symbiotically essential cytochrome oxidase cbb3 of Bradyrhizobium japonicum. Increase in the symbiotic effectiveness of all three mutants and in O2 consumption rate in free-living cultures was observed. Mutants Tb1 and TB16 were also characterized by an increase in fixNOQP gene expression. Consequently, the mutations probably affect at least two different steps of rhizobial respiratory metabolism operating both in free-living cells and endosymbiotic forms.

Bacterial Proteins↗
PubMed1998

Comparative analysis of Epstein-Barr virus (EBV) detection by nested-PCR and non-isotopic in situ hybridization in nasopharyngeal carcinoma (NPC).

The aims of this study were two-fold: first, to assess the relative diagnostic performance of non-isotopic in situ hybridization (ISH) and the nested polymerase chain reaction (nested-PCR) applied to Epstein-Barr virus (EBV) detection in a series of 55 unselected nasopharyngeal carcinoma (NPC) cases and, secondly, to correlate these data with histopathological classification. Our study shows that in 76.36% of NPC cases positive nuclear signals were observed using EBV-ISH. Overall, EBV-ISH positivity varied according to histological type, in that undifferentiated carcinomas showed a higher proportion of positive cases than differentiated cell carcinomas, although ISH results do not show significant differences in relation to histological types when employing two different schemes (WHO and Micheau). However, in adequate quality DNA samples (54 NPC cases), EBV-DNA was detected in 100% of cases using a nested-PCR, supporting the previous view that all histological types of NPC are in reality variants of EBV-infected neoplasia. ISH-negative cases probably reflect a lower sensitivity than PCR, particularly when a small number of viral copies are present, as well as a variable technical effectiveness for detected EBV, independent of the NPC histological type.

Adolescent↗
PubMed1998

Spanish study group on cochlear implants for persons with marginal benefit from acoustic amplification.

Recently the U.S. Food and Drug Administration approved the use of cochlear implants (CI) in patients with severe-to-profound sensorineural hearing loss with marginal benefit (< 30% speech discrimination) from hearing aids (HA). A multicentre trial was developed to determine whether this approval could be applied to the Spanish population. Nine postlingual adults from 3 centres were selected for the study. The mean preoperative unaided PTA threshold (0.25 to 4 KHz) was 108.6 dB HL for the poorer ear and 99.8 dB HL for the better. In all subjects the poorer ear was implanted with a Mini Nucleus 22 device. A single subject design study was used to compare performance with HA preoperatively and with CI postoperatively, or CI with contralateral HA. PTA measures and Spanish open set speech recognition tests were used. Comparing pre-implant levels with results after 6 months of CI use, all subjects improved significantly on all test measures: i) Mean aided soundfield threshold: 73.6 dB vs 39.8 dB ii) Mean bisyllabic recognition: 20% vs 57% iii) Mean consonant discrimination: 20% vs 49% iv) Mean CID sentences: 22% vs 73%. Five subjects discontinued use of the contralateral HA after implantation, three continued occasionally to use the HA, and one continued to use both on a full-time basis. Patients performed significantly better post-implant on speech recognition compared with their best pre-implant HA scores. Therefore the CI appears an appropriate treatment for Spanish speakers with a severe-to-profound hearing loss and marginal benefits with HA.

Adolescent↗
PubMed1998

Papillary thyroid carcinoma arising in the wall of a thyroglossal duct cyst.

The thyroglossal duct cyst is the most common anomaly in thyroid development. However, carcinomas arising in a thyroglossal duct cyst are rare entities. To date, approximately 125 cases have been reported, the majority being papillary thyroid carcinomas. In most cases the diagnosis is established only after excision of a clinically benign thyroglossal duct cyst. The etiology of such tumors remains unclear but de novo origin is generally proposed. Controversies exist in relation to a rational and effective therapeutic approach. A further case of thyroglossal duct papillary carcinoma affecting a 55 year-old Spanish man is presented to highlight the clinicopathological features of this condition. Preoperative computed tomography performed on our patient showed irregular calcium deposits adjacent to the hyoid bone. Cytohistological and immunohistochemical studies showed a papillary thyroid carcinoma with abundant psammoma bodies. Surgery consisted only of a Sistrunk procedure. In view of the prolonged course of papillary carcinoma, long-term follow-up is mandatory.

Carcinoma, Papillary↗