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Biomedical subjects

A Ruiz

Publications and source records attributed to A Ruiz.

At least 127 records · Page 7Linked to original sources
PubMed2000

MR imaging of infections of the cervical spine.

Spine infections are serious clinical conditions that carry high morbidity and mortality rates. Cervical spine infections usually require a more aggressive medical and surgical approach than infections in the rest of the spine. Often, more than one anatomic structure or compartment becomes affected. Topics discussed in this article include incidence and predisposing factors of spine infections, types of micro-organisms involved in several disease conditions, pathophysiology and clinical manifestations, and imaging findings and MR imaging features.

Bone Diseases, Infectious↗
PubMed1999

Seroprevalence of Trypanosoma evansi in dromedaries (Camelus dromedarius) from the Canary Islands (Spain) using an antibody Ab-ELISA.

After the description in Grand Canary Island of a case of dromedary trypanosomosis caused by Trypanosoma evansi in 1998, an indirect enzyme immunoassay for the detection of specific anti-T. evansi IgG (Ab-ELISA) was used to assess the seroprevalence of this disease on the Canary Islands. Seroprevalence was 9.0% in the four studied islands (Gran Canaria, Tenerife, Lanzarote and Fuerteventura), varying from 10.0 to 7.5% by island (not significantly different). Prevalence using Ab-ELISA was higher than that observed when a parasitological method (microscopic observation of blood smears) was used (1.3%).

Animals↗
PubMed1999

Cloning of the human phospholipase A2 activating protein (hPLAP) gene on the chromosome 9p21 melanoma deleted region.

Cutaneous malignant melanoma (CMM) is a common skin cancer. About 50% of CMM sporadic tumours have lost one copy of the chromosome 9p21 region. To identify genes involved in the initiation and/or progression of CMM we have characterised the 9p21 melanoma deleted region and screened the human expressed sequence tag (EST) databases (dbEST) to search for expressed genes. We have identified the gene that encodes the human orthologue of the rat phospholipase A2 activating protein (PLAP). PLAP was considered a potential candidate to be involved in malignant melanoma because it maps to the critical region for CMM and because the PLA2 gene has been identified as a modifier of the APC gene, responsible for the adenomatous polyposis phenotype in the mouse. PLAP encodes a protein of 738 amino acids and has a high DNA (90%) and protein (97%) sequence similarity with the rat and mouse PLAP protein. PLAP has a region of WD40 repeats in the amino-terminus, which allows us to include this protein in the superfamily of beta-transducin proteins. Northern blot hybridisation gave a fragment of 4.5 kb, with higher expression in heart compared to other tissues. PLAP was localised at chromosome 9p21, between marker AFM218xg11 and TEK. SSCP analysis of the coding region of PLAP revealed no variants in the studied samples, but one of six CMM samples analysed by RT-PCR showed specific inactivation of PLAP. Despite PLAP's important role in mediating several cellular responses and its localisation to the chromosome 9p21 region deleted in CMM, it is unlikely that point mutations or deletions in the coding region of PLAP are responsible for the initiation or progression of CMM. Further studies on PLAP inactivation should be performed to clarify its potential involvement in CMM.

Amino Acid Sequence↗
PubMed1999

Generation of a widespread Drosophila inversion by a transposable element.

Although polymorphic inversions in Drosophila are very common, the origin of these chromosomal rearrangements is unclear. The breakpoints of the cosmopolitan inversion 2j of D. buzzatii were cloned and sequenced. Both breakpoints contain large insertions corresponding to a transposable element. It appears that the two pairs of target site duplications generated upon insertion were exchanged during the inversion event, and that the inversion arose by ectopic recombination between two copies of the transposon that were in opposite orientations. This is apparently the mechanism by which transposable elements generate natural inversions in Drosophila.

Animals↗
PubMed1999

[Community-acquired pneumonia: impact of the use of a therapeutic strategy based on probability of short-term mortality].

BACKGROUND: To assess the impact of the use of a therapeutic strategy based on classifying patients with community-acquired pneumonia (CAP) according to the probability of short-term mortality. PATIENTS AND METHODS: During one year, all patients admitted to the Emergency Department with diagnosis of CAP were included. Clinicians were invited to treat patients according to a recently published protocol that stratifies patients into five categories (from low to high-risk mortality): patients assigned to class 1 were managed at home; patients included in classes 2 and 3 were assigned to a short-time period at emergency department before managed at home; and patients assigned to classes 4 and 5 were hospitalized. RESULTS: The final population analyzed included 101 patients. The rate of acceptability among clinicians was 96.7%. Patients were classified by the following terms: risk-class 1: 17 (16.8%); risk-classes 2 and 3: 40 (39.7%); risk-classes 4 and 5: 44 (43.6%). During follow-up, of the 57 non-hospitalized patients, 3 (5.2%) were subsequently admitted to hospital and 7 (12.2%) patients initially assigned to a short-time period at emergency department were hospitalized, and 1 (1.7%) of them died. By this program, the reduction of the hospitalization rate was 23.8%. CONCLUSION: A strategy of management of CAP based on a prognostic classification has a good safety and acceptability among clinicians, and reduces the rate of hospitalizations.

Adolescent↗
PubMed1999

Modulation of kainate-induced responses by pentobarbitone and GYKI-53784 in rat abducens motoneurons in vivo.

The modulation of kainate-induced responses by pentobarbitone and the 2,3-benzodiazepine GYKI-53784 (LY303070), a potent non-competitive AMPA antagonist, was studied in vivo using both extracellular recordings of antidromic field potentials and intracellular recordings from abducens motoneurons in ketamine/diazepam-anesthetized rats. In previous studies on pentobarbitone-anesthetized rats [M. Ouardouz, J. Durand, GYKI-52466 antagonizes glutamate responses but not NMDA and kainate responses in rat abducens motoneurons, Neurosci. Lett. 125 (1991) 5-8; M. Ouardouz, J. Durand, Involvement of AMPA receptors in trigeminal postsynaptic potentials recorded in rat abducens motoneurons in vivo, Eur. J. Neurosci. 6 (1994) 1662-1668; A. Ruiz, J. Durand, Blocking the trigeminal EPSPs in rat abducens motoneurons in vivo with the AMPA antagonists, NBQX and GYKI-53655, J. Neurophysiol. (1998) submitted], we showed that 2,3-benzodiazepines do not affect kainate-induced depolarizations in abducens motoneurons. Here, we tested whether pentobarbitone is involved in the pharmacological discrimination by 2,3-benzodiazepines between AMPA- and kainate-induced responses. Kainate-induced depolarizations were reversibly depressed after application of either GYKI-53784 and pentobarbitone. However, kainate-induced depolarizations were not inhibited by GYKI-53784 with pentobarbitone; they were even potentiated sometimes. Using extracellular recordings, we confirmed that in the presence of pentobarbitone, GYKI-53784 counteracts the effects of AMPA but not of kainate on antidromic field potentials in the abducens nucleus. Blockade of kainate-induced responses by GYKI-53784 was reversed with pentobarbitone, which appears relevant to the discrimination between AMPA- and kainate receptor-mediated responses in vivo. In the presence of pentobarbitone, kainate would depolarize motoneurons mainly via kainate receptors since kainate-induced responses were not depressed by 2,3-benzodiazepines. This finding strongly favors the existence of kainate receptors in adult motoneurons but their role is still unknown.

Abducens Nerve↗
PubMed1999

[Non-secreting pheochromocytoma of the broad ligament revealed by appendicular peritonitis].

BACKGROUND: Non-secreting pheochromocytoma is an endocrine tumor located in the adrenal medulla in 85% of the cases. Extra-adrenal localizations account for the other 15%. A broad ligament localization related to an accessory adrenal gland is exceptional. CASE REPORT: A tumoral formation was observed during computed tomographic exploration of appendicular peritonitis in a 25-year-old patient. The tumor had developed from an ectopic adrenal gland included in the large ligament of the uterus. Pathology reported non-secreting pheochromocytoma confirmed by immunolabeling. DISCUSSION: The broad ligament localization is exceptional for pheochromocytomas and may mislead diagnosis. Resection is the only treatment. Recurrence and metastases have been reported to develop in some cases many years later, particularly after incomplete resection. Pathogenically, this tumor is remnant embryonic chromaffin tissue issuing from the parasympathetic nodes and developing in an ectopic adrenal gland.

Adrenal Gland Neoplasms↗
PubMed1999

Molecular and biochemical characterization of lecithin retinol acyltransferase.

The enzyme responsible for conversion of all-trans-retinol into retinyl esters, the lecithin retinol acyltransferase (LRAT) has been characterized at the molecular level. The cDNA coding for this protein was cloned and its amino acid sequence deduced. LRAT is composed of a polypeptide of 230 amino acid residues with a calculated mass of 25.3 kDa. Tissue distribution analysis by Northern blot showed expression of a 5.0-kilobase transcript in the human retinal pigment epithelium as well as in other tissues that are known for their high LRAT activity and vitamin A processing. Affinity labeling experiments using specific compounds with high affinity for LRAT and monospecific polyclonal antibodies raised in rabbits against two peptide sequences for LRAT confirmed the molecular mass of LRAT as a 25-kDa protein. High performance liquid chromatography analysis of the reaction product formed by HEK-293 cells transfected with LRAT cDNA confirmed the ability of the transfected cells to convert [3H]all-trans-retinol into authentic [3H]all-trans-retinyl palmitate as chemically determined.

Acyltransferases↗
PubMed1999

Outpatient therapy with oral ofloxacin for patients with low risk neutropenia and fever: a prospective, randomized clinical trial.

BACKGROUND: Hospitalization and treatment with broad-spectrum intravenous antibiotics is the standard care for patients with neutropenia and fever. This randomized clinical trial evaluated the feasibility and efficacy of ambulatory care with oral ofloxacin for patients with low risk, chemotherapy-induced neutropenia and fever. METHODS: Patients with solid tumors who were treated with conventional dose chemotherapy, presented with fever (axillary temperature >38 degrees C on 2 occasions or >38.5 degrees C on a single occasion) and neutropenia (absolute neutrophil count, <500 cells/microL), and met low risk criteria were eligible for this study. They were randomized either to hospitalization and treatment with broad-spectrum intravenous antibiotics, which consisted of a combination of cefazidime and amikacin, or to outpatient treatment with oral ofloxacin. The definitions of fever of unknown origin, clinical and microbiologic infection, success, success with modification, and failure were the usual ones for this type of study. RESULTS: One hundred episodes were randomized, and 95 were evaluable (47 were randomized to ceftazidime/amikacin and 48 to ofloxacin). Baseline characteristics, as well as the proportion of patients with microbiologic and clinical infections, were similar in the two groups. In 91% of episodes in the inpatient group and 89% in the ofloxacin group, patients recovered uneventfully (P=1; 95% CI for the difference, -0.09 to 0.13), with 2 and 5 patients requiring modification of the antibiotics, respectively. Eight percent of episodes in the control group and 10.4% in the experimental group resulted in treatment failure. Eight patients (16%) in the outpatient group experienced failure with ambulatory care and were admitted to the hospital. CONCLUSIONS: Outpatient oral antibiotic therapy with oral ofloxacin for patients with low risk neutropenia and fever is safe and similar in efficacy to hospitalization and treatment with broad-spectrum parenteral antibiotics.

Administration, Oral↗
PubMed1999

Immunohistochemical comparative analysis of transforming growth factor alpha, epidermal growth factor, and epidermal growth factor receptor in normal, hyperplastic and neoplastic human prostates.

Immunoreaction to TGF-alpha was limited to the basal epithelial cells of focal areas in the normal prostates. In benign prostatic hyperplasia (BPH) the immunostained areas were more widespread and immunolabelling was observed in both basal and columnar (secretory) cells of the epithelium. Some cells in the connective tissue stroma were also stained. In prostatic adenocarcinoma, epithelial immunostaining was even more extensive and intense than in BPH, and some stromal cells were also stained. Epidermal growth factor (EGF) immunostaining was only present in some basal cells in normal prostates. In BPH, this immunoreaction was strong in the basal cells and even stronger in the secretory cells. In prostatic cancer, the intensity of epithelial cell immunoreactivity was intermediate between that of normal prostates and that of BPH specimens. EGF-receptor immunostaining was focal and located in the basal cells in normal prostates. In BPH, labelling was also localized in basal cells but extended to wider areas. Some stromal cells appeared weakly labelled. In the prostatic carcinoma, both basal and columnar cells appeared stained and the number of immunolabelled stromal cells was higher than in BPH. The results presented suggest that, in normal conditions, EGF and TGF-alpha act as autocrine growth factors for the basal cells of the prostatic epithelium. In BPH this action is maintained and, in addition, the columnar cells start to secrete both factors which are bound by the basal cell receptors, giving rise to a paracrine regulation which probably overstimulates basal cell proliferation. In prostatic carcinoma, besides these regulatory mechanisms, the acquisition of EGF-receptors by the secretory cells develops an autocrine regulation which might induce their proliferation.

Adenocarcinoma↗
PubMed1999

Comparative mapping of cosmids and gene clones from a 1.6 Mb chromosomal region of Drosophila melanogaster in three species of the distantly related subgenus Drosophila.

The successful hybridization of cosmid clones from Drosophila melanogaster (Sophophora subgenus) to the salivary gland chromosomes of other species as distantly related as those in the Drosophila subgenus attests their great potential for unravelling genome evolution. We have carried out, using 28 cosmids and 13 gene clones, a study of the organization of the D. melanogaster 95A-96A chromosomal region in three Drosophila subgenus species: D. repleta, D. buzzattii and D. virilis. These clones were first used to built an accurate map of this 1.6 Mb region of D. melanogaster chromosome 3R (Muller's element E). Then, they were hybridized and mapped to the homologous chromosome 2 of the other three distantly related species. The studied region is disseminated over 13 different sites of chromosome 2 in the Drosophila subgenus species, which implies a minimum of 12 inversion breakpoints fixed between the two subgenera. Extrapolation to the entire chromosome gives 90 fixed inversions. The D. melanogaster Pp1-96A-Acr96Aa segment conserved in D. repleta and D. buzzatii is longer than previously thought and is also conserved in D. virilis. In addition, three other D. melanogaster segments conserved in the three Drosophila subgenus species were found. Finally, our data indicate significant statistical differences in the evolution rate of Muller's element E among lineages, a result that agrees well with the previous cytogenetic data.

Animals↗
PubMed1999

What does the brain do while playing scrabble?: ERPs associated with a short-long-term memory task.

Event-related brain potentials (ERPs) were recorded while subjects performed the scrabble paradigm, a cued recall task that demands retrieving semantic memory information from long-term memory since subjects are not exposed to a previous study phase. The task combines short- and long-term memory processes and consists of forming words from a set of letters presented in random order. Short-term memory was manipulated by varying the number of letters (three, four and five) presented to the subject, while semantic memory was examined by comparing correct trials with no response trials. Behavioral results reveal that the subjects performed the task serially, as denoted by a linear reaction time increment as the number of random letters in the set increased. Short-term memory procedures were reflected by an amplitude increase of the N200 and by an amplitude decrease of the P300 increasing the number of letters. Successfully retrieving semantic information from long-term memory was indexed by a negative slow wave recorded at left frontal and left central sites, and by a positive slow wave predominant over right hemisphere sites. These findings provide evidence that semantic retrieval memory involves activity from both left and right hemispheres.

Adult↗
PubMed1999

Benign, preinvasive and invasive ductal breast lesions. A comparative study with quantitative techniques: morphometry, image- and flow cytometry.

The histological distinction between ductal hyperplasia of the breast, atypical ductal hyperplasia and ductal carcinoma in situ is difficult and subjective. To gain a better understanding of these lesions, we performed a comparative study comprising 20 cases of ductal hyperplasia without atypia, 20 cases of ductal hyperplasia with atypia, and 30 cases of ductal carcinoma in situ (well-, moderately- and poorly-differentiated), using quantitative techniques: image cytometry analysis, morphometry and DNA analysis, and DNA flow cytometry. Our results confirm that the mean nuclear area and volume progressively decreased from ductal carcinoma in situ to ductal hyperplasia without atypia. The difference was significant (p < 0.05) when comparing hyperplasia without atypia with hyperplasia with atypia and hyperplasia with atypia with poorly differentiated ductal carcinoma in situ. Atypical ductal hyperplasia values were comparable to those of well-differentiated ductal carcinoma in situ. DNA image cytometry proved significant (p < 0.05) when comparing hyperplasia without atypia with hyperplasia with atypia and hyperplasia with atypia with moderately- and poorly-differentiated ductal carcinoma in situ. DNA flow cytometry revealed significant differences only in the distribution of the DNA ploidy patterns (p < 0.05) when comparing hyperplasia without atypia with moderately- and poorly-differentiated DCIS. A comparison of the results obtained by image and flow cytometry showed that in 90% of the cases the IC and FC values were coincident, whereas in the remaining cases the DNA index was aneuploid by IC and diploid by FC.

Breast Neoplasms↗
PubMed1999

Management of injuries to great vessels during laparoscopy.

Laparoscopy is useful for diagnosis and treatment of gynecologic pathology. Although techniques and instrumentation have progressed significantly, and physicians have acquired more experience, a great deal of concern remains regarding possible major complications associated with this procedure. (J Am Assoc Gynecol Laparosc 6(1):101-104, 1999)

Adult↗
PubMed1999

Recombination rate predicts inversion size in Diptera.

Most species of the Drosophila genus and other Diptera are polymorphic for paracentric inversions. A common observation is that successful inversions are of intermediate size. We test here the hypothesis that the selected property is the recombination length of inversions, not their physical length. If so, physical length of successful inversions should be negatively correlated with recombination rate across species. This prediction was tested by a comprehensive statistical analysis of inversion size and recombination map length in 12 Diptera species for which appropriate data are available. We found that (1) there is a wide variation in recombination map length among species; (2) physical length of successful inversions varies greatly among species and is inversely correlated with the species recombination map length; and (3) neither the among-species variation in inversion length nor the correlation are observed in unsuccessful inversions. The clear differences between successful and unsuccessful inversions point to natural selection as the most likely explanation for our results. Presumably the selective advantage of an inversion increases with its length, but so does its detrimental effect on fertility due to double crossovers. Our analysis provides the strongest and most extensive evidence in favor of the notion that the adaptive value of inversions stems from their effect on recombination.

Analysis of Variance↗