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Biomedical subjects

C Rubio

Publications and source records attributed to C Rubio.

At least 19 recordsLinked to original sources
PubMed2003

Impact of preimplantation genetic diagnosis on IVF outcome in implantation failure patients.

Implantation failure (IF) is defined as three or more failed IVF attempts, and preimplantation genetic diagnosis (PGD) is being used in these patients to improve IVF outcome. PGD was performed in 49 implantation failure patients with a mean number of 4.2 +/- 1.6 previous IVF failures, and in nine fertile controls. Fluorescence in-situ hybridization (FISH) on blastomeres from biopsied day 3 embryos was performed for chromosomes 13, 16, 18, 21, 22, X and Y. There was a significantly higher rate of chromosomal abnormalities (67.4%) compared with controls (36.3%). In 57 cycles, a pregnancy rate of 34.0% and an implantation rate of 19.8% was observed in implantation failure patients compared with controls (33.3 and 24.1% respectively), with all the pregnancies in the implantation failure group coming from the transfer of at least one chromosomally normal blastocyst on day 5. It is concluded that in IVF patients, use of PGD along with blastocyst transfer improves IVF outcome.

Adult↗
PubMed2003

Chromosomal abnormalities and embryo development in recurrent miscarriage couples.

BACKGROUND: Chromosomal abnormalities are an important cause of spontaneous abortion and recurrent miscarriage (RM). Therefore, we have analysed the incidence of chromosomal abnormalities and embryo development in patients with RM. METHODS: Preimplantation genetic diagnosis (PGD) was performed on 71 couples with RM and 28 couples undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in-situ hybridization. RESULTS: The implantation rate in RM patients was 28% and three patients (13%) miscarried. The percentage of abnormal embryos was significantly increased (P < 0.0001) in RM patients compared with controls (70.7 versus 45.1%). All of the embryos were abnormal in 19 cycles (22.1%) and repeated PGD cycles yielded similar rates of chromosomal abnormalities in 14 couples. Anomalies for chromosomes 16 and 22 were significantly higher (P < 0.01) in RM cases. In the RM population, euploid embryos reached the blastocyst stage more frequently than abnormal embryos (61.7 versus 24.9%; P < 0.0001). CONCLUSIONS: RM is associated with a higher incidence of chromosomally abnormal embryos, of which some are able to develop to the blastocyst stage. IVF plus PGD is an important step in the management of these couples, but the technique has to move towards a full chromosome analysis.

Abortion, Habitual↗
PubMed2003

Prevalence and incidence of hyperplastic polyps and adenomas in familial colorectal cancer: correlation between the two types of colon polyps.

BACKGROUND AND AIMS: Colorectal adenomas are recognised as precursors of colorectal carcinomas. The significance of hyperplastic (metaplastic) colorectal polyps is unknown. The relationship between hyperplastic polyps and adenomas, and the prevalence and incidence of these lesions were evaluated in individuals predisposed to familial colorectal cancer. METHODS: A total of 299 individuals participating in our surveillance programme during 1990-2000 were retrospectively evaluated. Subjects were classified into three groups: hereditary non-polyposis syndrome (HNPCC) (n=108), hereditary colorectal cancer (HCRC) (n=127), and individuals with empirical risk estimates-two close relatives (TCR) (n=64). Findings from 780 colonoscopies were evaluated regarding prevalence and incidence of hyperplastic polyps and adenomas. Correlations between hyperplastic polyps and adenomas were calculated by Pearson correlation. RESULTS: In total, 292 hyperplastic polyps and 186 adenomas were observed in 98 and 90 individuals, respectively. A positive correlation was found between the numbers of hyperplastic polyps and adenomas (r=0.40; p<0.001). Correlations between adenomas and hyperplastic polyps were similar in the three groups. The risk of detecting new hyperplastic polyps (odds ratio 5.41) or adenomas (OR 2.56) increased significantly when there was a positive finding at first colonoscopy. CONCLUSION: Hyperplastic polyps as well as adenomas may identify individuals with a high risk of colorectal cancer. This information is important when these individuals are selected and included in tailored surveillance programmes.

Adenoma↗
PubMed2003

[Anaphylaxis].

Anaphylaxis is a potentially mortal, underdiagnosed clinical picture. The most frequent triggering agents are drugs and foodstuffs. The first therapeutic option, adrenaline, although clearly indicated, is not carried out with the desired frequency due basically to the high number of cases of anaphylaxis that are not diagnosed as such. In patients with a first episode of anaphylaxis, posterior aetiological diagnosis is crucial to avoid the appearance of new episodes. The only case of anaphylaxis in which immunotherapy with the allergen must be evaluated, is that in which the causal agent is the poison of hymenopters.

Anaphylaxis↗
PubMed2002

Low-grade dysplasia in extensive, long-standing inflammatory bowel disease: a follow-up study.

PURPOSE: Extensive, long-standing inflammatory bowel disease is associated with an increased risk of developing colorectal carcinoma. Low-grade dysplasia has been used as a marker for malignant transformation and by some as an indication for prophylactic colectomy. The aim of the present study was to follow up all inflammatory bowel disease patients with extensive, long-standing colitis who had low-grade dysplasia in flat colonic mucosa. METHODS: All patients with low-grade dysplasia in flat mucosa found at screening or at surveillance colonoscopy with at least one follow-up colonoscopy or with colectomy were included. RESULTS: Sixty patients (40 males; mean age at diagnosis, 24 +/- 12 (range, 3-59) years) were found and followed up for a mean of 10 +/- 6 (range, 1-22) years. Mean time from onset of disease to discovery of low-grade dysplasia was 17 +/- 11 (range, 1-55) years. Low-grade dysplasia was present in more than 1 biopsy in 37 (62 percent) of 60 patients at the index colonoscopy. Low-grade dysplasia was again detected in 1.8 (1-6) subsequent colonoscopies in 44 (73 percent) of 60 patients. High-grade dysplasia was found in 2 of 11 patients with dysplasia-associated lesion or mass at follow-up. Thirteen patients were subjected to colectomy (7 for dysplasia, 6 for therapy failure). Dysplasia was confirmed in five of these patients. CONCLUSION: Although low-grade dysplasia occurred at several colonic levels and at repeated colonoscopies in 73 percent of the patients, no progression to high-grade dysplasia was found during 10 years of follow-up, except in 2 cases with dysplasia-associated lesion or mass. Colectomy in cases with single or repeated low-grade dysplasia in flat mucosa does not appear to be justified.

Adolescent↗
PubMed2002

Photophysical, photochemical, and thermodynamic properties of shikimic acid derivatives: calycin and rhizocarpic acid (lichens).

Photophysical and photochemical parameters of the lichen metabolites calycin and rhizocarpic acid were determined. Experiments were carried out in micellar solutions of 3% Brij 35, at pH 2 and 12, and in acetonitrile. Both metabolites absorb in the UV-A and UV-B regions, and emit fluorescence in the visible region of the solar spectrum. Shifts were not observed in the absorption spectra, at pH 2 and 12. The low phi(c), between 10(-5) and 10(-2), shows that both compounds are photostable in the experimental conditions. For rhizocarpic acid, two values of pK(a) were obtained: 5.1 corresponding to the hydroxyl group, and 9.0 corresponding to the protonated nitrogen. Calycin presents only one value of pK(a): 4.9, that is attributed to the hydroxyl group. L-(+)-Gluconic-gamma-lactonic acid was used as a reference model; the compound showed greater photoinstability, demonstrating that the photodegradation observed occurs mainly in the oxolane carbonylic ring.

Hydrogen-Ion Concentration↗
PubMed2002

Potential migration release of volatile compounds from plastic containers destined for food use in microwave ovens.

Several commercially available plastic containers of polycarbonate, polypropylene-copolymer, polypropylene-20% talcum, polypropylene random and styrene-acrylonitrile designed for heating food in microwave ovens were studied. The analytical procedure based on a purge & trap (P&T) GC-MS was optimized. It consisted of heating the materials at 100 degrees C in a P&T system coupled in line with GC-MS equipment. The compounds released from the materials were then identified through their mass spectra. Variables such as the time of purge using helium as the carrier gas in the system, sample temperature, the type of solid trap, the desorption temperature and the time as well as chromatographic separation of all the compounds released from the plastic were optimized. Compounds such as methylbenzene, ethylbenzene, 1-octene, xylene, styrene and 1,4-dichlorobenzene were found in all the containers. Quantitative analysis and potential migrations are reported and discussed.

Cooking↗
PubMed2002

Adenoma prevalence and cancer risk in familial non-polyposis colorectal cancer.

BACKGROUND AND AIMS: Polypectomy in the colon has been shown to prevent colorectal cancer in both the general population and in familial colorectal cancer. Individuals with a family history of colorectal cancer have an increased risk of the disease. Over a period of 10 years, 304 subjects at risk were included in ongoing surveillance with regular colonoscopies. To compile the medical findings and experience generated during this period, a retrospective cross sectional study was performed. SUBJECTS: Subjects were classified into three family groups: families with hereditary non-polyposis colorectal cancer (HNPCC); families with hereditary colorectal cancer (HCC, non-Lynch syndrome); and a third group of families with only empirical risk estimates based on a family history of two close relatives (TCR) with colorectal cancer. METHODS: The risk population was studied with regard to age at onset, prevalence, number, cancer risk, size, dysplasia, and distribution of adenomas. A comparison was made within the family groups and with a reference group representing the general population. RESULTS: In total, 195 adenomas and six cancers were detected among 85 individuals. The relative risk of having an adenoma in the whole risk population compared with the general population was 2.6. Subjects from TCR families had most adenomas and HNPCC subjects had the least. A shift from proximal adenomas to distal carcinomas in families with HCC and TCR suggested a higher cancer risk in distal adenomas in these syndromes. HNPCC families showed a younger age at onset and adenomas with a higher degree of dysplasia. In HNPCC, there was a similar localisation of adenomas and carcinomas, suggesting a high risk of cancer in all adenomas. CONCLUSIONS: There was clear overrepresentation of adenomas in all three family types compared with the reference population. In HNPCC, we found earlier onset of adenomas and faster progression to cancer. Families with HCC, and even more so TCR subjects, had a later onset and lower risk of cancer from proximal adenomas. Based on these results, surveillance protocols in Sweden have been revised.

Adenoma↗
PubMed2001

Refractive acoustic devices for airborne sound.

We show that a sonic crystal made of periodic distributions of rigid cylinders in air acts as a new material which allows the construction of refractive acoustic devices for airborne sound. It is demonstrated that, in the long-wave regime, the crystal has low impedance and the sound is transmitted at subsonic velocities. Here, the fabrication and characterization of a convergent lens are presented. Also, an example of a Fabry-Perot interferometer based on this crystal is analyzed. It is concluded that refractive devices based on sonic crystals behave in a manner similar to that of optical systems.

Journal Article↗
PubMed2001

Enzymatic hydrolysis of (chloromethyldimethylsilyl)-2-propenyl acetate isomers: atypic specificity of Candida antarctica lipase.

Enzymatic hydrolysis of a mixture of (chloromethyldimethylsilyl)-2-propenyl acetate isomers was investigated by using immobilized Candida antarctica lipase as biocatalyst. TLC analysis and 1H NMR spectroscopy were used to monitor the extent of the reaction. At 60 degrees C, the enzyme exhibited a high selectivity towards 3-(chloromethyldimethylsilyl)-2-propenyl acetate which was almost quantitatively hydrolyzed, whereas, only 11% of 2-(chloromethyldimethylsilyl)-2-propenyl acetate reacted with the lipase. Consequently, the unreacted acetate was readily purified from the reaction medium by flash column chromatography and deacetoxylated in acidic methanol to give the corresponding hydroxy compound in a 71% global yield. On the other hand, without lipase, chemical treatment of the acetate mixture resulted in much lower yields in hydroxy compounds followed by a tedious purification process.

Biotechnology↗
PubMed2001

COL11A1 in FAP polyps and in sporadic colorectal tumors.

BACKGROUND: We previously reported that the alpha-1 chain of type 11 collagen (COL11A1), not normally expressed in the colon, was up-regulated in stromal fibroblasts in most sporadic colorectal carcinomas. Patients with germline mutations in the APC gene show, besides colonic polyposis, symptoms of stromal fibroblast involvement, which could be related to COL11A1 expression. Most colorectal carcinomas are suggested to be a result of an activated Wnt- pathway, most often involving an inactivation of the APC gene or activation of beta-catenin. METHODS: We used normal and polyp tissue samples from one FAP patient and a set of 37 sporadic colorectal carcinomas to find out if the up-regulation of COL11A1 was associated with an active APC/beta-catenin pathway. RESULTS: In this study we found a statistically significant difference in COL11A1 expression between normal tissue and adenomas from one FAP patient, and all adenomas gave evidence for an active APC/beta-catenin pathway. An active Wnt pathway has been suggested to involve stromal expression of WISP-1. We found a strong correlation between WISP-1 and COL11A1 expression in sporadic carcinomas. CONCLUSIONS: Our results suggest that expression of COL11A1 in colorectal tumors could be associated with the APC/beta-catenin pathway in FAP and sporadic colorectal cancer.

Adenomatous Polyposis Coli↗
PubMed2001

Host genetic background at CCR5 chemokine receptor and vitamin D receptor loci and human immunodeficiency virus (HIV) type 1 disease progression among HIV-seropositive injection drug users.

The effect of polymorphisms on genes encoding the CCR5 chemokine receptor and vitamin D receptor (VDR) in human immunodeficiency virus (HIV) type 1 disease progression was analyzed in a cohort of 185 HIV-seropositive injection drug users. Results confirmed a lack of association in patients with HIV disease between CCR5 wtDelta32 heterozygosity and a slow progression to AIDS and to a CD4 cell count <200 cells/microL. In contrast, a more rapid disease progression was associated with the VDR-BB genotype. A higher proportion of this genotype was found in patients with <200 CD4 cells/microL (P=.009; odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3-4.7), as well as a faster progression both to AIDS (1993 CDC classification [CDC 1993]) and to a CD4 cell count <200 cells/microL. When the analysis was restricted to patients with a VDR-bb genetic background, patients with CCR5 wtDelta32 heterozygosity were overrepresented in CDC 1993 nonprogressors (P=.033; OR, 0.28; 95% CI, 0.08-0.92) and in those with >200 CD4 cells/microL (P=.062; OR, 0.26; 95% CI, 0.06-1.08). Also, patients with CCR5 wtDelta32 heterozygosity showed a slow progression both to AIDS CDC 1993 and to a CD4 cell count <200 cells/microL.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[Hepatitis C virus genotypes. Study of 302 patients coinfected by the human immunodeficiency virus].

BACKGROUND: To study the distribution of different HCV genotypes in HIV-infected patients. PATIENTS AND METHOD: This study was carried out in 302 HIV/HCV-coinfected patients who were followed-up at the HIV/AIDS Unit of the Arnau de Vilanova University Hospital of Lleida (Spain). HCV genotypes were determined by Inno-Lipa HCV II technique (Innogenetics, Belgium). RESULTS: 143 patients (51.43%) had a genotype-1, followed by genotype-3 (81 patients; 29.13%), genotype-4 (53 patients; 19.06%), and genotype-2 (one patient; 0.35%). It was not possible to know the genotype in 24 patients (NT). CONCLUSIONS: In our health care area, HCV genotype-1 was the commonest among HIV/HCV-coinfected patients. However, a given HIV-infected patient with HCV antibodies has practically the same probability of having a genotype-1 as a genotype non-1.

Genotype↗
PubMed2001

Genetic pathways in the evolution of morphologically distinct colorectal neoplasms.

Colorectal adenomas can be morphologically classified as exophytic or flat. Polypoid cancers and cancers arising de novo (ie., without any adenomatous component) might be the results of genetic progression from exophytic and flat adenomas, respectively. In this study, we examined 94 morphologically distinct neoplastic specimens for mutations in K-RAS and analyzed 10 microsatellite loci tightly linked to the tumor suppressor genes APC, p53, DCC/SMAD4, hMSH2, and hMLH1. K-RAS mutations were significantly associated with exophytic adenomas [11 of 21 (52%)] compared to flat adenomas [2 of 13(15%), P < 0.03] and polypoid cancers [17 of 25 (68%)] compared to cancers arising de novo [7 of 25 (28%), P < 0.01]. Two polypoid cancer cases demonstrated three and four different K-RAS mutations, respectively, suggesting multiple areas of clonal expansion. Cancers arising de novo were significantly associated with loss of heterozygosity (LOH) at chromosome 3p compared to pol ypoid cancers [6 of 18(33%) versus 1 of 20(5%), P < 0.03], whereas the prevalence of LOH at chromosomes 2p, 5q, 17p, and 18q and microsatellite instability were not different between the groups. For all cancers, LOH at chromosomes 17p and 18q occurred in 47 and 51%, respectively. However, LOH at 17p and 18q occurred in 0 and 16% of benign lesions, respectively, suggesting their role in malignant transformation. There was no difference in LOH at chromosomes 17p and 18q between exophytic and flat lesions. These findings suggest that (a) mutant K-RAS is associated with the exophytic growth of colonic neoplasms, and that (b) some colorectal cancers arising de novo lose chromosome 3p during their evolution, which is not seen in polypoid cancers. Half of all cancers lose chromosomes 17p and 18q at or near the malignant transition of benign lesions as reported previously, irrespective of morphology. There may be more than one genetic avenue for colorectal cancer formation, and this correlates with the morphological characteristics.

Adenoma↗
PubMed2001

Differential expression of aquaporin 8 in human colonic epithelial cells and colorectal tumors.

BACKGROUND: The gene expression pattern in tumor cells differs from that in corresponding normal cells. In order to identify differentially expressed genes in colorectal tumors and normal colorectal epithelium, a differential display experiment was used to compare RNA expression in normal and tumor tissue samples. RESULTS: One gene fragment was expressed only in normal tissue and not, or to a much lesser extent, in the adenomas, carcinomas and cancer cell lines. The isolated gene fragment was identical to Aquaporin 8 (AQP8), a water channel protein. In situ hybridization demonstrated that AQP8 was expressed in the cells facing the lumen in the normal colonic epithelium. CONCLUSION: Our result suggests that the expression of AQP8 is a marker of normal proliferating colonic epithelial cells and suggest these cells to be involved in fluid transport in the colon.

Adenoma↗
PubMed2001

Use of fluorescence in situ hybridization to assess the chromosomal status of embryos obtained from cryopreserved oocytes.

OBJECTIVE: To analyze the chromosomal status of human embryos obtained from frozen-thawed oocytes. DESIGN: Fluorescence in situ hybridization analysis of embryos obtained after oocyte cryopreservation. SETTING: Department of Obstetrics and Gynecology at the University of Perugia, Italy, and the Instituto Valenciano de Infertilidad, Spain. PATIENT(S): Oocyte donors (n = 43). Fertilization, development, and chromosomal status of the embryos were compared with a control group (n = 18) of patients undergoing preimplantation genetic diagnosis for sex chromosome-linked diseases. INTERVENTION(S): Collection of oocytes after conventional ovarian stimulation and cryopreservation using propanediol as the cryoprotectant and a slow freezing procedure. Microinjection of surviving metaphase II oocytes and evaluation of fertilization and embryo development up to blastocyst stage. Chromosomal analysis after embryo biopsy. MAIN OUTCOME MEASURE(S): Survival, fertilization, and blastocyst rates. Embryo chromosomal analysis employing specific probes for chromosomes 13,18,21, X and Y. RESULT(S): The overall survival rate was 59.4%. There was no difference between cryopreservation and control groups in fertilization rates (76.5% vs. 90.5%) or blastocyst development (29.6% vs. 35%). The percentage of blastocysts from the original number of cryopreserved oocytes was only 5.6%, comparable to the 5.9% obtained in the control group. The percentage of embryos with abnormal number of chromosomes in the cryopreservation group (28.6%) was comparable to the 26% observed in the controls. CONCLUSION(S): Fertilization and cleavage rates after oocyte freezing are acceptable. Survival is, however, still poor, leading to overall results that make the technique clinically inefficient. There is no increase in the rate of chromosomal abnormalities, indicating that the technique is, nevertheless, safe enough to be further explored and improved.

Adult↗
PubMed2001

Microsatellite Instability and hMLH1 and hMSH2 expression analysis in familial and sporadic colorectal cancer.

Immunohistochemical expression analysis of mismatch repair gene products has been suggested for the prediction of hereditary nonpolyposis colorectal cancer (HNPCC) carrier status in cancer families and the selection of microsatellite instability (MSI)-positive tumors in sporadic colorectal cancer. In this study, we aimed to evaluate hMSH2 and hMLH1 immunohistochemistry in familial and sporadic colorectal cancer. We found that immunohistochemistry allowed us to identify patients with germline mutations in hMSH2 and many cases with germline mutations in hMLH1. However, some missense and truncating mutations may be missed. In addition, hMLH1 promoter methylation, commonly occurring in familial and sporadic MSI-positive colorectal cancer, can complicate the interpretation of immunohistochemical expression analyses. Our results suggest that immunohistochemistry cannot replace testing for MSI to predict HNPCC carrier status or identify MSI-positive sporadic colorectal cancer.

Adaptor Proteins, Signal Transducing↗