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Biomedical subjects

C Rubio

Publications and source records attributed to C Rubio.

At least 19 recordsLinked to original sources
PubMed2000

Germline BRCA1 and HMLH1 mutations in a family with male and female breast carcinoma.

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant disease, predisposing to the development of colorectal cancer and other tumor types such as endometrial, small bowel, stomach, ovary and urinary tract carcinoma, while most investigators find no association between HNPCC and cancer of the breast. We have identified hMLH1 mutations in 2 Amsterdam-criteria HNPCC families where both male and female gene carriers were affected with breast cancer. To investigate whether these breast cancers were caused by other genetic factors, we analyzed the 2 breast cancer susceptibility genes BRCA1 and BRCA2. In one family we did not find any mutation in the breast cancer genes, while in the other, a BRCA1 mutation segregated in the breast cancer cases. Hereditary breast cancer, and in particular BRCA1 tumors, display discrete histo-pathological and immunohistological characteristics. The tumor from a woman with both hMLH1 mutations and a BRCA1 mutation exhibited typical BRCA1 histology, e.g., grade 3 invasive ductal carcinoma with dense lymphocytic infiltration, and immunohistology, estrogen receptor (ER) negative, progesterone receptor (PgR) negative, strongly p53 positive, c-erbB-2 negative and highly Ki67 positive (>50% stained cells). The histology of the breast tumor from the man with both one hMLH1 mutation and a BRCA1 mutation was a grade 2 invasive ductal carcinoma without any special BRCA1 features. Immunohistology was also different. This might merely reflect a true difference in male breast tumor progression vs. female. We cannot exclude that the combined effect of BRCA1 and hMLH1 dysfunction has a bearing on tumor progression.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Microsatellite instability as a predictor of a mutation in a DNA mismatch repair gene in familial colorectal cancer.

Germline alterations in human DNA mismatch repair genes are associated with hereditary nonpolyposis colorectal cancer (HNPCC). Mutation analysis of the genes reveals carriers with a high risk of colorectal cancer, who will benefit from surveillance. We wanted to find the best predictive parameter of a germline mutation in those genes among patients with familial colorectal cancer. Affected members from a total of 83 unrelated colorectal cancer families previously analyzed for mutations in MSH2 and MLH1 were used to evaluate different parameters' ability to predict a germline mutation. We studied various clinical criteria such as family structure, age of onset, and prevalence of endometrial cancer, as well as microsatellite instability in the tumors from the families. In total, 124 tumors from 59 of the families were tested for microsatellite instability (MSI) using PCR-based mono- and dinucleotide markers to establish whether the families could be scored as MSI-positive or -negative. The finding of MSI-positive tumors in a family was the best predictor of a germline mutation, and was found in 73% of the MSI-positive, but in less than 3% of the MSI-negative families (P < 0.0001). In contrast, MSI in unselected colorectal cancer is not as useful, since most of these MSI-positive tumors are sporadic. The finding of microsatellite instability in colorectal tumors seems efficient enough even to select those with germline mutations among families fulfilling HNPCC Amsterdam criteria, once used in identification of the DNA mismatch repair genes. Genes Chromosomes Cancer 27:17-25, 2000.

Adult↗
PubMed2000

Rectal tumour staging: MR imaging using pelvic phased-array and endorectal coils vs endoscopic ultrasonography.

The aim of this study was to compare MR imaging and endoscopic ultrasonography (EUS) for the local staging of rectal tumours. Forty-nine patients were examined on a 1.5-T MR unit using either a pelvic phased-array coil (n = 37) alone or combined with an endorectal coil (n = 12). Sagittal and axial sequences with T2-weighted fast spin-echo and axial T1-weighted spin-echo techniques were employed. The EUS technique was performed using a flexible endosonoscope. The results were compared with findings at histopathological sectioning of the specimen. The T-stage on MR correlated with histopathology in 32 of 49 patients and on EUS in 29 of 49 patients. The N-stage on MR correlated with histopathology in 22 of 49 patients and on EUS in 26 of 49 patients. Tumour penetration of the rectal wall was predicted by MR with 86 % sensitivity and 65 % specificity, and by EUS with 89% sensitivity and 33% specificity. Preoperative radiotherapy was administered to 40 of the patients after the examinations which may explain some of the overstaging by MR and EUS. Three patients with surgically and histopathologically confirmed invasion of neighbouring organs in the pelvis were detected preoperatively on MR but none on EUS. Tumour penetration of the rectal wall and local lymph node metastases cannot accurately be predicted with MR or EUS. Magnetic resonance, however, seems to be more useful for preoperative identification of clinically occult advanced disease.

Aged↗
PubMed2000

Somatic mutations of the APC, KRAS, and TP53 genes in nonpolypoid colorectal adenomas.

Colorectal adenomas are macroscopically visible morphological changes of the mucosa that can develop focal carcinoma in the absence of surgical intervention. The successive molecular changes proposed to occur at different stages in the adenoma-carcinoma sequence were primarily based on DNA studies of exophytic, polypoid-type adenomas. Not all colorectal lesions, however, display an exophytic phenotype and a presumed distinct colorectal neoplasm, the nonpolypoid adenoma, was subsequently described as a precursor of colorectal cancer. The low incidence of KRAS mutations in nonpolypoid colorectal adenomas reported previously suggested a different genetic basis for the transformation process in these lesions. We have pursued the identification of genetic changes in benign sporadic nonpolypoid colorectal adenomas in a selected Swedish patient group with no family history of colorectal cancer. Mutation screening of the adenomatous polyposis coli (APC), KRAS, and TP53 genes was conducted using the protein truncation test, heteroduplex-single-strand conformation polymorphism analysis, and denaturing gradient gel electrophoresis on PCR-amplified fragments. Fourteen mutations in the APC gene were characterized in 10/20 samples. Mutations in the KRAS and TP53 genes were identified in 3/57 and 4/51 adenomas, respectively. The mutation frequencies and distribution of mutations in APC correlate with published data on exophytic adenomas. The low mutation frequency of the TP53 gene is consistent with the benign nature of the research material. KRAS activation (an early event in polypoid colorectal adenomas) apparently does not play a significant role in nonpolypoid adenoma development but may result in the development of a polypoid configuration. Genes Chromosomes Cancer 27:202-208, 2000.

Adenoma↗
PubMed1999

Missense mutations in hMLH1 associated with colorectal cancer.

One of the most prevalent hereditary syndromes associated with colorectal cancer is hereditary nonpolyposis colorectal cancer (HNPCC). The inherited gene defects in HNPCC have been shown to reside in DNA mismatch repair genes, mostly hMSH2 or hMLH1. Most HNPCC patients are heterozygous with regard to the relevant mismatch repair gene; they have one normal and one mutated allele, and mismatch repair in normal somatic cells is functional. Cancer predisposition in HNPCC is believed to be associated with the loss of the wild-type allele in somatic cells, resulting in defective DNA mismatch repair. This gives rise to DNA microsatellite instability (MSI), an increased somatic mutation rate, and eventually, to the accumulation of mutations in genes involved in colorectal carcinogenesis. In support of this theory, colorectal tumors in HNPCC patients and in mice deficient for hMSH2 or hMLH1 show MSI. Here, we describe two missense mutations in hMLH1 exon 16 associated with colorectal cancer. Interestingly, the tumors do not show MSI. This raises some potentially important issues. First, even microsatellite-negative colorectal tumors can be associated with germline mutations and these will be missed if an MSI test is used to select patients for mutation screening. Second, the lack of MSI in these cases suggests that the mechanism involved in carcinogenesis could be different from that generally hypothesized.

Adaptor Proteins, Signal Transducing↗
PubMed1999

In vitro fertilization plus preimplantation genetic diagnosis in patients with recurrent miscarriage: an analysis of chromosome abnormalities in human preimplantation embryos.

OBJECTIVE: To analyze the incidence of numeric chromosomal abnormalities in preimplantation embryos from women with unexplained recurrent miscarriage (RM) so as to seek an etiology and to determine whether the use of IVF may be indicated to treat these cases. DESIGN: Prospective controlled study. SETTING: University laboratory of reproductive genetics and a tertiary referral center for infertility. PATIENT(S): Nine women with a mean (+/-SD) of 3.9 +/- 0.6 RMs who were undergoing IVF and preimplantation genetic diagnosis, and a control group of young (n = 10) and older (n = 6) patients who were undergoing preimplantation genetic diagnosis because of sex-linked diseases. INTERVENTION(S): In vitro fertilization, embryo culture for 72 hours, blastomere biopsy, and analysis of chromosomes 13, 16, 18, 21, 22, X, and Y with the use of fluorescent in situ hybridization. Transfer of chromosomally normal embryos into the uterus. MAIN OUTCOME MEASURE(S): Numeric chromosomal abnormalities in human embryos. RESULT(S): Sixty-six embryos from patients with RM were compared with 62 embryos from young patients and 41 embryos from older patients. There was a significant increase in the rate of abnormal embryos in the patients with RM and the older patients compared with the controls. Abnormalities in most of the chromosomes studied were higher in the RM group than in the control group, especially those affecting chromosome 13. CONCLUSION(S): There was an increase in numeric chromosomal abnormalities in preimplantation embryos from women with RM that could be the cause of infertility in many couples with unexplained RM. The use of IVF in such circumstances may be indicated if successful preimplantation genetic diagnosis is added to the procedure.

Abortion, Habitual↗
PubMed1999

Differentiation of three biotypes of Malassezia species on human normal skin. correspondence with M. globosa, M. sympodialis and M. restricta.

One hundred and twenty lipid dependent Malassezia spp. isolates were obtained from the clinically normal skin of 38 healthy adult volunteers by swabbing three different body sites (back, chest and scalp). Ninety-six percent of these strains could be grouped into three biotypes on the basis of microscopic, cultural, metabolic and biochemical (catalase, esculin and lipase (C-14)) characteristics. The differential features were simple to determine and easily reproduced. Moreover, the three biotypes were referable to the species M. globosa (biotype 1), M. sympodialis (biotype 2) and M. restricta (biotype 3). Based on their microscopic features, cultural properties and body site locations, we suggest that biotype 1 /M. globosa corresponds to the description of Pityrosporum orbiculare (round yeast cells with a narrow base, very frequently found on the upper trunk), and biotype 3/M. restricta corresponds to the concept of P. ovale (oval yeast cells with a broad budding base, located mainly on the scalp). Pleomorphic biotype 2/M. sympodialis, most frequently found in the back, does not clearly fit into any of the Pityrosporum species.

Azure Stains↗
PubMed1999

Implications of sperm chromosome abnormalities in recurrent miscarriage.

PURPOSE: Our purpose was to assess the existence of sperm chromosome abnormalities in recurrent pregnancy loss in an assisted reproduction program. METHODS: In this prospective study, 12 sperm samples from couples undergoing in vitro fertilization with two or more first-trimester spontaneous abortions were analyzed. Diploidy and disomy in decondensed sperm nuclei were assessed for chromosomes 13, 18, 21, X, and Y using two- and three-color fluorescence in situ hybridization. RESULTS: Sex chromosome disomy in sperm samples from recurrent abortion couples was significantly increased compared to that from internal controls (0.84% vs 0.37%). In a subpopulation of seven couples who underwent oocyte donation, mean frequencies for sex chromosome disomy (1%) were even higher and diploidy (0.43%) was also significantly increased. CONCLUSIONS: These results suggest an implication of sperm chromosome abnormalities in some cases of recurrent pregnancy loss.

Abortion, Habitual↗
PubMed1999

Differentiated effects on splanchnic homeostasis by selective and non-selective endothelin receptor antagonism in porcine endotoxaemia.

1. The non-selective endothelin (ET) receptor antagonist bosentan has been shown to restore systemic and gut oxygen delivery and reverse intestinal mucosal acidosis in porcine endotoxin shock. 2. To further elucidate the specific role of the ETA as opposed to the ETB receptor and their effects in the splanchnic region a non-selective (ET(MIX)ra) A-182086 and selective ETA (ET(A)ra) PD155080 and ETB (ET(B)ra) A-192621 receptor antagonists were administered, separately or simultaneously (ET(A+B)ra) 2 h after onset of endotoxin shock. These four groups were compared to a control group receiving only endotoxin and vehicle. 3. Thirty-nine pigs were anaesthetized and catheterized for measurement of central and regional haemodynamics. A tonometer in the distal ileum was used for measurement of mucosal PCO2. Blood gases and plasma ET-1-LI levels as well as histological samples from the gut were assessed. Intervention was started 2 h after onset of endotoxemia and the experiments were terminated after 5 h. 4. Endotoxin-induced changes in systemic, gut oxygen delivery and portal hepatic vascular resistance and systemic acidosis were effectively counteracted by both ET(A+B)ra an ET(MIX)ra. ET(A)ra administration was not effective while ET(B)ra proved to be fatal as all animals in this group died prior to full time of the experiment. While both ET(A+B)ra and ET(MIX)ra improved gut oxygen delivery only the latter attenuated the profound endotoxin-induced ileal mucosal acidosis. 5. The lethal effect seen from selective ETB receptor antagonism in the current study may be due to increased ETA receptor activity as plasma levels of ET-1 is increased several fold by blocking the ETB receptor and thereby the plasma-ET-1-clearing function. Furthermore, a loss of endothelial ETB receptor vasodilating properties may also have contributed to the lethal course in the ET(B)ra group. 6. The findings in this study suggest that ET is involved in the profound endotoxin-induced disturbances in splanchnic homeostasis in porcine endotoxaemia. Furthermore, antagonism of both ETA and ETB receptors is necessary to effectively counteract these changes.

Animals↗
PubMed1999

Visualization of hydatid elements: comparison of several techniques.

Some techniques available at our laboratory were tested for their ability to aid in the morphological diagnosis of hydatid elements (Echinococcus granulosus ["Taenia echinococcus"]) isolated from cysts in humans and sheep. Unstained, methanol-fixed hooklets were fluorescent, most starkly so under violet light (excitation filter wavelength, 405 nm; long-pass filter wavelength, 495 nm). Auramine-rhodamine and Gram procedures failed to stain hooklets. Ziehl-Neelsen stain yielded indifferent results when organisms were viewed under transmitted light but resulted in a surprisingly intense red fluorescence when organisms were viewed under green light (excitation, 546 nm; long pass, 590 nm). Wheatley trichrome stain gave better and more uniform results than fuchsin. Ryan trichrome blue stain was the best under transmitted light; hooklets stained uniformly and intensely and were easily distinguishable from the background. Very satisfactory results were also obtained with a much simpler procedure (modified Baxby technique: no fixation, steaming hot 1% safranin for 2 min, and malachite green for 30 s). Therefore, Ryan and modified Baxby stains are recommended for the examination of E. granulosus under transmitted light. For fluorescence microscopy, Ziehl-Neelsen stain under green excitation light, or violet light with no staining, is also very useful. Epifluorescence microscopy is especially convenient for examining samples concentrated by filtration, as it renders the filter pores inconspicuous.

Animals↗
PubMed1999

Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation.

BACKGROUND AND AIMS: Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy. METHODS: Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination. Light of 337, 405, or 436 nm wavelength was used as excitation. Stepwise multivariate linear regression analysis was performed. RESULTS: With 337 nm excitation, 100% sensitivity and 96% specificity was obtained between normal mucosa and adenomas. Seventy seven per cent of the hyperplastic polyps were classified as non-neoplastic. When exciting with 405 and 436 nm, the possibility of distinguishing different types of tissue was considerably better in the ALA patients than in the non-ALA patients. CONCLUSIONS: The in vivo point measurements imply that a good discrimination between normal tissue and adenomatous polyps can be obtained using the LIF technique. Excitation at 337 nm and at 405 nm or 436 nm using ALA gives good results. LIF also shows potential for distinguishing adenomatous from hyperplastic polyps. The number of detection wavelengths could be reduced if chosen properly.

Adenoma↗
PubMed1999

Rectal adenocarcinoma: assessment of tumour involvement of the lateral resection margin by MRI of resected specimen.

The aim of the present study was to investigate whether MRI could predict tumour involvement of the lateral resection margin on resected rectal cancer specimens. 26 specimens obtained after total mesorectal excision were examined in the sagittal and axial plane on a clinical 1.5 T MR system using phased-array surface coils. The shortest distance between the deepest point of tumour penetration and the lateral resection margin was measured. This distance is referred to as LRM. The results were correlated to measurements on digital images of giant histopathological sections. The total number of lymph nodes and lymph node metastases was also counted. LRM was less than or equal to 1 mm (a distance considered for non-radically excised tumours) in eight of the histopathological specimens. On MR images of the resected specimen, LRM was less than or equal to 1 mm in seven of these specimens. LRM was shorter in MR examinations than in histopathological giant sections in 11 specimens. The sensitivity, specificity, positive and negative predictive values for prediction of tumour involvement of the lateral resection margin (LRM < or = 1 mm) by MR of the resected specimen were 88%, 78%, 64% and 93%, respectively. Presence of lymph node metastases could not accurately be predicted by MR. However, it is concluded that the presence of a tumour free lateral resection margin can be predicted by MRI of resected rectal specimens when this exceeds 1 mm.

Adenocarcinoma↗
PubMed1999

Technetium-99m-HMPAO-labeled leukocyte imaging in patients with seronegative spondyloarthropathies.

OBJECTIVE: Gut inflammation is frequent among patients with seronegative spondyloarthropathies (SSp). The purpose of this study was to evaluate the presence of positive abdominal findings in patients with SSp who did not have clinical symptoms or signs of inflammatory bowel disease (IBD). This represents a new indication for abdominal 99mTc-HMPAO-labeled leukocyte scintigraphy. METHODS: Eighty-six patients (59 with SSp and 27 controls) were prospectively imaged with 99mTc-HMPAO-labeled leukocytes. RESULTS: Leukocyte imaging was positive in 33 patients with SSp (56%), 27 of these patients scored between 2+ and 4+ (51%). Four (15%) control patients also had positive findings. CONCLUSION: These findings provide evidence linking SSp with intestinal inflammation. SSp may be an important new indication for 99mTc-HMPAO-labeled autologous leukocyte scintigraphy.

Adult↗
PubMed1999

Beneficial effects of ropivacaine in rat experimental colitis.

Ropivacaine, a new, long-acting local anesthetic agent, has been shown to have beneficial effects in the treatment of ulcerative colitis. Treatment with this drug results in prompt symptomatic relief. The aim of this study was to examine the effects of ropivacaine on mucosal healing and to investigate whether ropivacaine can restore the decreased colonic contractility seen in the diseased state. Colitis was induced in rats by a single intrarectal administration of trinitrobenzene sulfonic acid. Mucosal healing was assessed after 1 week of therapy. The effects on colonic contractility were examined either after 1 week of treatment or by application of the drugs to untreated, inflamed rat colon segments placed in organ baths. After the induction of colitis, daily intracolonic treatment with ropivacaine for 1 week reduced morphological damage and myeloperoxidase activity. One week of treatment also restored the contractile response to acetylcholine. By adding ropivacaine directly to untreated inflamed colonic segments in organ baths, the contractile response to acetylcholine was increased compared with controls. For comparison, the effects of budesonide and 5-aminosalicylic acid were also examined. Ropivacaine improved mucosal healing and restored colonic motor activity in experimental colitis, similar to budesonide but superior to 5-aminosalicylic acid.

Acetylcholine↗
PubMed1998

The role of ataxia-telangiectasia heterozygotes in familial breast cancer.

The role of ataxia-telangiectasia (AT) heterozygotes in breast cancer has been controversial. We have found previously an overrepresentation (3.4%) of ATM mutations in a subset of 88 selected breast cancer patients with a family history of breast cancer, leukemia, and lymphoma. This prevalence is comparable to the estimated value (3.8%) from epidemiological study. To further examine the possibility that ATM is correlated to breast cancer, we screened for ATM germ-line mutations in another 100 breast cancer patients with a family history of breast cancer. We used the protein truncating test and found one new germ-line mutation. This figure (1%) is consistent with the observed 0.2-1% carrier frequency for AT. We also studied breast tumors from ATM mutants, and three showed retention of both alleles, whereas the fourth showed loss of the mutant allele. We conclude that the contribution of heterozygous ATM mutations to familial breast cancer is minimal. Even if the ATM gene were causative in these cases, it is not likely to act as a tumor suppressor.

Ataxia Telangiectasia↗
PubMed1998

Validation of ELISA for the detection of African horse sickness virus antigens and antibodies.

The mortality rate in susceptible populations of horses during an epizootic of African horse sickness (AHS) may be in excess of 90%. Rapid and reliable assays are therefore essential for the confirmation of clinical diagnoses and to enable control strategies to be implemented without undue delay. One of the major objectives of a recent European Union funded project was the validation of newly developed diagnostic assays which are rapid, sensitive, highly reproducible and inexpensive, for the detection of African horse sickness virus (AHSV) antigens and antibodies. The Laboratorio de Sanidad y Produccion Animal (LSPA) in Algete, Spain was charged with the responsibility of co-ordinating and supplying samples of viruses and antisera to the participating laboratories in Spain, France and the United Kingdom. The panels comprised 76 antigen samples for assay by indirect sandwich ELISAs and 53 serum samples for antibody detection by either indirect or competitive ELISAs. Results generated by ELISA for each laboratory were analysed in LSPA in terms of their relative sensitivities and specificities. There was a good agreement between the ELISAs used for either antigen or antibody detection. The participating groups agreed that any field sample giving a doubtful result would always be retested by ELISA and an alternative assay.

African Horse Sickness↗
PubMed1998

The heparin-glutathione test: an alternative to the hypo-osmotic swelling test to select viable sperm for intracytoplasmic sperm injection.

OBJECTIVE: To evaluate the heparin-glutathione test (HEGLUT) for the selection of viable sperm for intracytoplasmic sperm injection (ICSI). DESIGN: A prospective study. SETTING: Department of Pediatrics, Obstetrics and Gynecology, University of Valencia and Instituto Valenciano de Infertilidad. PATIENT(S): Semen samples from healthy donors and patients with infertility. INTERVENTION(S): Sperm samples were kept in culture for different periods in Ham's F-10 medium supplemented or not supplemented with heparin, reduced glutathione (GSH), or a heparin-GSH mixture. Control and heparin-GSH-treated spermatozoa were injected into hamster oocytes. The HEGLUT and ICSI were performed. MAIN OUTCOME MEASURE(S): Sperm nuclear decondensation, progressive and nonprogressive motility, and male pronucleus formation. RESULT(S): The maximum proportion of sperm nuclear decondensation (28.7%+/-2.1% versus 2.6%+/-0.5% in the control group) was reached after 60 minutes of incubation in the presence of a heparin-GSH mixture. Differences in the percentages of progressive and nonprogressive motility among treatments and times of incubation, although statistically significant, were biologically negligible. No statistically significant differences were observed in the rate of sperm head decondensation (8.2% [4/49] versus 11.1% [6/54]) and male pronucleus formation (18.4% [9/49] versus 22.2% [12/541) after the injection of control and treated spermatozoa into hamster oocytes. CONCLUSION(S): The HEGLUT may offer an alternative to the hypo-osmotic swelling test for the selection of viable sperm for ICSI.

Animals↗