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Biomedical subjects

L Donoso

Publications and source records attributed to L Donoso.

At least 19 recordsLinked to original sources
PubMed2003

Factors related to non-participation in a population-based breast cancer screening programme.

The main objectives were to describe the measures taken by women to detect breast disease prior to invitation to participate in a screening programme for breast cancer, and to identify factors related to non-participation in this programme. A cross-sectional study was designed at the Breast Cancer Early Detection Program of Sabadell-Cerdanyola (BCEDP), using data collected in interviews conducted face to face or over the telephone with 13 760 women participating in the programme and 280 non-participants. A total of 74.2% of the participants versus 70.4% of the non-participants reported having taken measures to detect breast disease, and 71.7% of the participants had undergone mammography versus 69.6% of the non-participants. Of the 10 057 women who had had mammograms, 58% had done so less than 2 years previously. Factors found to be associated to non-participation in the multivariate analysis were: higher level of education, higher occupational skills or working at home, self- or gynaecological examination of breasts, and having received hormone replacement therapy. Higher age group was the only factor that increased the probability of not having undergone mammography previously. Despite the high prevalence of prior measures to detect breast cancer and the similar prevalence between participating and non-participating women, this behaviour is much less prevalent in the group of women 60 years of age or older.

Age Factors↗
PubMed2000

Efficacy of low and standard midazolam doses for gastroscopy. A randomized, double-blind study.

AIM: To evaluate the efficacy and safety of two different doses of intravenous midazolam (35 and 70 microg/kg) compared to placebo in patients undergoing gastroscopy. PATIENTS AND METHODS: Sixty patients scheduled for diagnostic gastroscopy were selected according to factors previously reported to affect tolerance (Eur J Gastroenterol Hepatol 1999; 11:201-204) and were randomly assigned to receive premedication with midazolam 35 microg/kg iv, midazolam 70 microg/kg iv or placebo iv. Oxygen saturation was continuously monitored during the procedure. Patients' tolerance, time to discharge and post-sedative inconvenience were evaluated using visual analogue scales and a questionnaire. RESULTS: Patients receiving either dose of midazolam showed better tolerance of gastroscopy than those receiving the placebo. Fewer patients receiving 70 or 35 microg/kg of midazolam were reluctant to undergo a further gastroscopy compared to those receiving the placebo (2, 1 and 9 patients respectively, P = 0.01). Compared to patients receiving midazolam 70 microg/kg, those receiving midazolam 35 microg/kg were discharged earlier (29.3+/-14.4 versus 43.1+/-12.4 min respectively, P < 0.001), experienced less post-sedative inconvenience (8 versus 15 patients slept for > 1 h at home respectively, P = 0.02), and suffered fewer clinically relevant desaturation episodes (< 90%) (0 versus 5 patients respectively, P = 0.04). CONCLUSIONS: Low doses of intravenous midazolam (35 microg/kg) are adequate and safe when sedation is indicated for gastroscopy.

Adult↗
PubMed1999

Epitope discovery using bacteriophage display: the minimum epitope of an anti-IRBP antibody.

The purpose of this study was to determine, using random peptide library (RPL) technologies, the minimal epitope requirements of the mouse monoclonal anti-interphotoreceptor-retinoid-binding protein antibody, H3B5. This previously characterized antibody is used as an example to examine whether RPL's offer a relatively easy and rapid route to obtaining detailed epitope mapping data.A pentadecamer random peptide library (RPL) displayed on the major coat protein (gene 8) of filamentous bacteriophage (F88-4-15) was used as a target for selection by the anti-IRBP monoclonal antibody, H3B5. Three rounds of library selection were performed, and 90 of the resultant RPL clones were examined for affinity to H3B5 by enzyme-linked immunosorbent assay (ELISA). DNA sequencing of ELISA positive clones provided sequence of the region encoding the random peptide. After three rounds of selection of the RPL, 76.7% of clones examined interacted with H3B5, 17.7% did not show significant binding and 6.6% bound to control antibody also. The essential elements of the peptide epitope were determined by sequence comparison of 24 clones to be the four amino-acid sequence (Aspartic or glutamic acid)-Proline-Arginine-(Leucine, Isoleucine or Valine). This motif [(D/E) PR (L/I/V)] is in agreement, but at greater resolution, than previous synthetic peptide studies where the motif AASEDPRL was identified. Other motifs were found which bound to H3B5 but did not share primary structure similarities (peptidomimetics). Selection from a RPL has rapidly defined the minimal requirements for the H3B5 epitope in fine detail. Such a process offers great potential for investigating antibody-antigen interactions and core sequences of an epitope, and enables the identification of motifs in other proteins which may be recognized by the antibody, providing information on possible cross-reactivity.

Amino Acid Sequence↗
PubMed1999

Identification of factors that influence tolerance of upper gastrointestinal endoscopy.

OBJECTIVE: Unsedated gastroscopy is unpleasant for some patients. The identification of factors related to tolerance would permit the selection of patients for sedation. The aim of the present study was to identify these factors. METHODS: Five hundred and nine patients underwent diagnostic gastroscopy after the administration of topical pharyngeal anaesthesia, without sedation. Patients were grouped as to whether they had undergone prior examinations or not. Tolerance was assessed with a visual analogue scale and a questionnaire. RESULTS: Two hundred and seventy-three (54%) patients underwent gastroscopy for the first time, and 236 (46%) patients had prior experience. Patient tolerance was poor in 84 of 273 (31%) patients undergoing gastroscopy for the first time, and in 61 of 236 (26%) patients with prior experience. Logistic regression analysis identified the following variables related to poor tolerance: (a) in patients undergoing gastroscopy for the first time: presence of gag reflex (odds ratio (OR) = 3.42, 95% confidence interval (CI) 1.90-6.17), apprehension (OR = 2.57, CI 1.33-4.95), young age (OR = 0.95, CI 0.93-0.98) and high level of anxiety (OR = 1.91, CI 0.96-3.89); (b) in patients with prior experience: apprehension (OR = 4.21, CI 1.93-9.20), poor tolerance of prior examinations (OR = 4.92, CI 1.93-12.5) and female (OR = 2.23, CI 1.09-4.57). CONCLUSIONS: The above-mentioned factors are predictive of poor tolerance, and may enable the identification of those patients who might benefit more from sedation for gastroscopy.

Adolescent↗
PubMed1998

Loss of heterozygosity on the long arm of chromosome 11 in orbital embryonal rhabdomyosarcoma (OERMS): a microsatellite study of seven cases.

OBJECTIVES. To investigate, by means of microsatellite analysis, regions of chromosome 11 involved in the genesis of embryonal rhabdomyosarcoma (ERMS) localized to the orbit. METHODS. Microsatellite analysis was carried out on seven cases of orbital ERMS by comparing the electrophoretic migration patterns of PCR-amplified microsatellites of chromosome 11 from both constitutional (blood) and tumor genotypes. Five of the tumors analyzed were samples frozen at the time of surgery, and two were paraffin embedded. RESULTS. Overall, microsatellites D11S1396 (11q13.1-q22.3) and D11S976 (11q) showed loss of heterozygosity (LOH) in all tumor samples, thus indicating the presence, on the long arm of chromosome 11, of one or more tumor suppressor genes with a possible role in the genesis of the disease. CONCLUSION. While the role of genes on the short arm of chromosome 11 in the genesis of ERMS is well established, much less is known of the possible involvement of tumor suppressor genes on the long arm of the same chromosome. This is the first report showing the possible involvement of tumor suppressor genes in this portion of the chromosome in ERMS localized to the orbit.

Journal Article↗
PubMed1998

Hyperechoic liver nodules: characterization with proton fat-water chemical shift MR imaging.

PURPOSE: To evaluate proton fat-water chemical shift fast low-angle shot magnetic resonance (MR) imaging for differentiation of fat-containing hyperechoic liver nodules from hyperechoic liver nodules without a fatty component. MATERIALS AND METHODS: T1-weighted fast low-angle shot fat-water chemical shift gradient-echo MR imaging was performed in 96 patients without cirrhosis with 138 hyperechoic liver nodules. In-phase and opposed-phase breath-hold images were acquired. The percentage of signal intensity variation between in-phase and opposed-phase images and the spleen-to-lesion contrast ratio were used to differentiate liver nodules. RESULTS: Chemical shift MR images showed fat in 15 (11%) hyperechoic nodules (two angiomyolipomas and 13 nodular fatty infiltrations of the liver). The mean percentage of signal intensity variation between in-phase and opposed-phase images was 156% (standard error, 43.5%) in nodules with fat and -0.16% (standard error, 0.96%) in nodules without fat (P = .003). Spleen-to-lesion contrast was similar on in- and opposed-phase images in lesions without fat (mean difference, -0.0107; standard error, 0.012), whereas the mean difference in fat-containing nodules was 0.805 (standard error, 0.225; P = .003). The area under the receiver operating characteristic curve was 0.97 for signal intensity variation. CONCLUSION: Hyperechogenicity in certain liver nodules is caused by fat. Chemical shift MR imaging allows accurate differentiation between these and other hyperechoic lesions with no fat component.

Adipose Tissue↗
PubMed1997

Design and implementation of a relational database used in the management of patients with retinoblastoma.

Clinical data are most useful in the management of patients with complex medical problems if they are accurate, reliable, and easily accessible by physicians and the medical community at large. Furthermore, the data are most valuable when they can be shared among cooperating institutions. We describe a computer system which exhibits a uniform taxonomy, an integrated on-line dictionary of clinical terms, a coherent temporal layout, and persistent spatial integrity with regard to the values of the variables. The system is user friendly and provides real time data access which can be retrieved by structured query language or may be programmed to be used as part of an international network in the management of patients with retinoblastoma, a malignant and potentially fatal tumor of childhood. Furthermore, because of its design flexibility, this system provides for potential application to other ophthalmic disorders, such as malignant uveal melanoma, and other areas of medicine as well.

Databases, Factual↗
PubMed1996

Factors predicting failure of endoscopic injection therapy in bleeding duodenal ulcer.

BACKGROUND: The aim of this study was to assess the factors that may cause failure of endoscopic injection in patients bleeding from a duodenal ulcer. METHODS: One hundred twenty patients admitted for a bleeding duodenal ulcer with active arterial hemorrhage or a nonbleeding visible vessel were included. RESULTS: Endoscopic injection was not feasible in 14 of 120 (11.6%) patients because of inaccessibility or massive hemorrhage. The remaining 106 patients underwent endoscopic therapy by injection of adrenaline and polidocanol. The efficacy (achievement of definitive hemostasis) of endoscopy therapy was 83% (88 of 106). Univariate analysis showed that failure of endoscopic injection was related to age, presence of shock, ulcer size greater than 2 cm, and hemoglobin level. Multivariate analysis showed that ulcer size greater than 2 cm (p = 0.005) and the presence of shock (p = 0.03) were factors predictive of endoscopic treatment failure. Failure to achieve hemostasis (p < 0.001) and poor physical status measured by American Society of Anesthesiology classification (p = 0.02) were significantly related to mortality. CONCLUSIONS: Ulcer size and severity of hemorrhage are predictive of endoscopic injection failure in patients bleeding from high-risk duodenal ulcers. Survival is determined by clinical status and associated diseases.

Aged↗
PubMed1995

Flow reversal in the right anterior branch of the portal vein: "bicolor portal vein" color Doppler analysis.

The purpose of this study is to describe a phenomenon of bidirectional flow, "bicolor portal vein" (BPV), within the right anterior branch of the portal vein (RAPV), with color Doppler imaging (CDI). We prospectively studied with CDI the intrahepatic portal vein and its branches in 316 consecutive patients in search of areas of nonlaminar flow within the RAPV. Forty patients were excluded from the study due to varied conditions that precluded an accurate CDI study. A prospective design allowed us to record the frequency of appearance, systematically measure a set of parameters in each patient, and establish different groups for comparison. We found an area of BPV within the RAPV in six patients. Five of them had a history of liver disease (8.2% of the patients with known liver disease). The BPV was consistently portrayed as a well-defined blue oval-shaped area of flow reversal attached to the medial side of the RAPV immediately before its bifurcation, suggesting a rotary motion of blood. All six patients presented a transverse diameter of the RAPV significantly larger than the rest of the patients (p < 0.05). Furthermore, blood flow measurements within the RAPV of the six patients with BPV were found to be significantly higher when compared with the rest of the patients (< 0.05). Knowledge of the possible presence of a BPV within the RAPV can prevent diagnostic confusion with reversal of flow, a truly pathologic condition related to liver disease.

Humans↗
PubMed1995

Fatty metamorphosis of hepatocellular carcinoma: detection with chemical shift gradient-echo MR imaging.

PURPOSE: To assess the value of chemical shift gradient-echo (GRE) magnetic resonance (MR) imaging with the fast low-angle shot (FLASH) technique to detect fatty metamorphosis in hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Sixty-three cirrhotic patients with 69 HCCs underwent MR imaging at 1.0 T with chemical shift GRE technique. Both opposed-phase and in-phase FLASH imaging with breath holding was performed, and the percentage variation in signal intensity of the nodules between the two images was calculated. RESULTS: Chemical shift GRE imaging depicted fat in 10 HCCs (14%). In these cases, the percentage variation in signal intensity increased notably and was 88.6%-369.3% (mean, 174.7%), which indicated fatty content (sensitivity, 100%; specificity, 100% when compared with fine-needle aspiration cytology). In the remaining 59 nodules, the percentage of signal intensity variation ranged from 12.7% to -19.1% (mean, -4.0%). CONCLUSION: Chemical shift GRE MR imaging can be used to detect fatty metamorphosis in HCC.

Biopsy, Needle↗
PubMed1994

Controlled trial of tamoxifen in patients with advanced hepatocellular carcinoma.

Thirty-six consecutive patients with advanced hepatocellular carcinoma and chronic liver disease were randomly allocated to two groups: group I included 20 patients who were treated with 10 mg bid. tamoxifen and group II with 16 non-treated patients. The two groups were homogeneous according to clinical and analytical data. Survival curves in the tamoxifen-treated patients improved significantly when compared with the non-treated group (p = 0.01). Cumulative survival at the end of the first year was 48.5% in the treated patients and 9.1% in controls. Median survival was 261 days in the treated group vs. 172 in the non-treated group (p < 0.05). Complications of cirrhosis and worsening of the performance status test occurred less in the treated patients than in the controls, but not significantly so. Tamoxifen was well tolerated and no marked side effects were observed. In this series, tamoxifen improved survival in patients with advanced hepatocellular carcinoma.

Aged↗
PubMed1994

Concordance between parental origin of chromosome 13q loss and chromosome 6p duplication in sporadic retinoblastoma.

Two hypotheses are capable of explaining nonrandom loss of one parent's alleles at tumor suppressor loci in sporadic cases of several pediatric cancers, including retinoblastoma--namely, preferential germ-line mutation or chromosome imprinting. We have examined 74 cases of sporadic retinoblastoma for tumors in which at least two genetic events--loss of heterozygosity for chromosome 13q markers and formation of an isochromosome 6p--have occurred. Sixteen cases were found to contain both events. In 13 of 16 such tumors, the chromosomes 13q that were lost and chromosomes 6p that were duplicated are derived from the same parent. These data may be explained within the framework of the genome imprinting model but are not predicted by preferential germ-line mutation.

Chromosome Deletion↗
PubMed1993

Spiculated lesions of the breast: mammographic-pathologic correlation.

Spiculated breast lesions may be caused by both benign and malignant processes, including sclerosing adenosis, postsurgical scar, radial scar, tuberculosis (rare), posttraumatic oil cysts, infiltrating ductal carcinoma, ductal carcinoma in situ (rare), infiltrating lobular carcinoma, and tubular carcinoma. Mammographically, such lesions are often similar, and only some can be differentiated on the basis of morphologic characteristics. Although microcalcifications are often associated with breast carcinoma, not all spiculated lesions with microcalcifications are malignant. Sclerosing adenosis occurs with punctate microcalcifications, but the lesion often has a radiolucent center, compared with the opaque center generally found in malignant spiculated lesions. Radial scar may occasionally occur with microcalcifications and usually has a radiolucent center, but the latter is not a reliable criterion for differentiation from carcinoma. The spicules of benign lesions are often caused by fibrous tissue, lipid-filled spaces surrounded by histiocytes, or sclerotic stroma, whereas the spicules of malignant lesions are due to tumor infiltration, desmoplastic response, or periductal fibrosis. Mammography alone is frequently not reliable for making the specific diagnosis. Clinical breast examination, additional mammographic views, and needle or surgical biopsy are often required.

Adult↗
PubMed1993

Percutaneous neurolysis of the celiac plexus via the anterior approach with sonographic guidance.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of sonographically guided percutaneous neurolysis of the celiac plexus in patients with abdominal tumors or chronic pancreatitis in whom systemic analgesics were ineffective. SUBJECTS AND METHODS: Neurolysis of the celiac plexus was performed in 38 patients, 34 with neoplastic disease and four with chronic pancreatitis. Under sonographic guidance, a 22-gauge needle was advanced by the anterior route to the area above the celiac plexus, and 30-40 ml of 50% alcohol was injected. Pain relief was assessed 1 week, 6 months, and 1 year after the procedure. Patients subjectively rated the pain after treatment as totally relieved, partially relieved, or unchanged. RESULTS: At 1 week and at 6 months after treatment, pain was totally relieved in 61% of patients, partially relieved in 31%, and unchanged in 8%. After 1 year, pain was totally relieved in 39%, partially relieved in 52%, and unchanged in 9%. The complications observed were five cases of mild diarrhea and one case of retroperitoneal pain, which subsided with conservative treatment. CONCLUSION: The anterior, sonographically guided approach appears to be as successful as other percutaneous techniques for neurolysis of the celiac plexus.

Abdominal Neoplasms↗
PubMed1992

Retinoblastoma: messenger RNA for interphotoreceptor retinoid binding protein.

Surgically excised retinoblastomas from 14 patients (age range nine months to two years) were assessed by immunocytochemistry for the expression of photoreceptor-specific proteins and neuronal and glial cell markers. Adjacent tissues were examined for messenger RNA expression of interphotoreceptor retinoid-binding protein (IRBP) using Northern blots. For immunocytochemical stains (ABC method), monoclonal and polyclonal antibodies included S-Ag, rhodopsin, neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP), IRBP, neural adhesion molecule (N-CAM), and rod and cone specific transducin (TR alpha and TC alpha). Histopathology revealed mostly poorly differentiated tumors with necrosis and lack of Flexner-Wintersteiner rosettes. Immunocytochemical staining showed focal IRBP expression in one of the tumors and S-antigen in two cases. Immunoreactivity with rhodopsin was negative. N-CAM, a neural adhesive protein which appears to be involved in the regulation of adhesive interaction during neuronal differentiation, was positive except in two cases. All tumors showed immunoreactivity with NSE, whereas GFAP staining was limited to the perivascular glial tissue confirming the essential neuronal nature of retinoblastoma cells. TC alpha was detected in all tumors and TR alpha in one case. Messenger RNA for IRBP was detected in tumors in which IRBP immunoreactivity could not be detected.

Antibodies, Monoclonal↗