Biomedical subjects

M Arroyo

Publications and source records attributed to M Arroyo.

At least 19 recordsLinked to original sources

PubMed2006

Role of the BRAF mutations in the microsatellite instability genetic pathway in sporadic colorectal cancer.

BACKGROUND AND AIMS: Between 10 and 15% of all cases of colorectal cancer are the result of microsatellite instability (MSI) in the genetic pathway due to an alteration in the DNA repair genes. Tumors with high MSI are characterized by a better prognosis. The BRAF oncogene has been linked to the MSI pathway in tumorogenesis. The objective of this study was to determine whether alterations in BRAF are related to MSI and whether they can result in differences in survival rates. METHODS: The study cohort comprised 351 patients diagnosed with sporadic colorectal cancer. MSI was determined in accordance with the National Cancer Institute's (NCI) recommendations by means of PCR and sequence analyses. Mutational analysis of the BRAF gene was performed by real-time PCR and subsequent sequencing of the altered samples. The methylation pattern of the hMLH1 gene was determined using methylation-specific PCR analyses of bisulfite-treated DNA and the results confirmed by sequencing. RESULTS: Of the patients tested, 6.9% showed high MSI and 3.7% showed a BRAF gene mutation. hMLH1 methylation was observed in 67.2% of the patients with MSI and/or the BRAF alteration. The BRAF mutation was related to the MSI genetic pathway (P < 0.0001) and with hMLH1 methylation. In the analysis of overall survival only MSI had an independent prognostic value for the risk of death. Patients with the BRAF mutation showed a higher risk of death, although this association was found not to be statistically significant. CONCLUSIONS: There is a subgroup of carcinomas which develop via the MSI pathway that carry an alteration of the BRAF gene. This alteration confers a poorer outcome on these patients within the total group of patients with MSI who have a better prognosis. This hypothesis should be further investigated in a larger study population due to the low incidence of BRAF mutations in colorectal cancer.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Testosterone: activation or organization of spatial cognition?

Previous studies in animals have revealed effects of both prenatal and current testosterone on brain organization and behavior. However, it is unclear how these effects translate to the human brain. Here, we refine previous procedures to clarify the relative contribution of prenatal versus current testosterone indices to cognitive function. Sixty-nine subjects performed four computerized tasks measuring mental rotation, targeting, figure-disembedding and perceptual discrimination. Using stepwise regression analyses, performance was related to free testosterone assayed in saliva samples and to second-to-fourth finger length ratios (2D:4D), a putative index of prenatal testosterone exposure. The exclusive predictor for mental rotation was found to be sex, while 2D:4D was found to be the sole predictor of targeting, exhibiting a curvilinear relation, and figure-disembedding performance, showing a linear relation. These findings suggest a substantial role for prenatal testosterone but not current testosterone in determining cognitive performance.

Aptitude↗

PubMed2006

[Utility of vasopressin in cardiopulmonary resuscitation].

Many vasopressants have been studied in cardiopulmonary resuscitation (CPR) to increase cerebral and coronary perfusion. Although there is a debate on the utility of epinephrine, this is the one that has been used historically, above all after verifying that other agents such as norepinephrine, metoxamine or phenylephrine, have not been shown to be more effective. Currently, due to the good experimental results, the use of vasopressin (ADH) in CPR is being evaluated. However there is little (only three studies) and debated evidence based on randomized clinical trials (norepinephrine or ADH) in humans. Once these are reviewed, it can be concluded: The results of the three randomized studies in humans obtain different results regarding the utility of ADH in cardiorespiratory arrest (CRA) secondary to ventricular fibrillation, electro-mechanical dissociation or asystole. More prospective studies are needed to know the role of ADH in prolonged CRA and in asystole, that may be the subgroups that can benefit the most from this drug. The neurological repercussion of a drug in the context of CRA should be evaluated before its inclusion in the CPR guides.

Cardiopulmonary Resuscitation↗

PubMed2006

NSAIDs-induced gastrointestinal damage. Review.

Non-steroidal anti-inflammatory drugs (NSAIDs), along with analgesics, are the most widely prescribed medication in the world. However, NSAIDs cause numerous side effects, being the gastrointestinal (GI) events the most common ones with an increase of risk of serious GI complications between 2.5- and 5-fold, as compared with individuals not taking NSAIDs. Factors that increase the risk for serious events in NSAID-using patients include a history of ulcer or ulcer complications, advanced age (=or>65 years), the use of high-dose NSAIDs, more than one NSAID, anticoagulants or corticosteroid therapy. If NSAID therapy is required, we must balance GI and cardiovascular risk and the therapy should be prescribed at the lowest possible dose and for the shortest period of time. The use of NSAID without gastroprotective co-therapy is considered appropriate in patients<65 years, not taking aspirin and having no GI history. In patients with GI risk factors, but no cardiovascular risk, coxibs or NSAIDs plus proton pump inhibitor (PPI) or misoprostol are valid options. Patients with a history of ulcer bleeding should receive coxib plus PPI therapy and should be tested and treated for Helicobacter pylori infection. Coxib therapy has better GI tolerance than traditional NSAIDs and PPI therapy is effective both in treatment and prevention of NSAID-induced dyspepsia and should be considered in patients who develop dyspepsia during NSAID or coxib therapy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Isolation from Gluconacetobacter diazotrophicus cell walls of specific receptors for sugarcane glycoproteins, which act as recognition factors.

Glycoproteins from sugarcane stalks have been isolated from plants field-grown by size-exclusion chromatography. Some of these glycoproteins, previously labelled with fluorescein isothiocyanate, are able to bind to the cell wall of the sugarcane endophyte, N2-fixing Gluconacetobacter diazotrophicus, and largely removed after washing the bacterial cells with sucrose. This implies that sugarcane glycoproteins use beta-(1-->2)-fructofuranosyl fructose domains in their glycosidic moiety to bind to specific receptors in the bacterial cell walls. These receptors have been isolated by affinity chromatography on a sugarcane glycoprotein-agarose matrix, desorbed with sucrose and characterized by sodium dodecyl sulfate polyacrylamide gel electrophresisand capillary electrophoresis (CE).

Cell Wall↗

PubMed2005

p16 Gene methylation in colorectal tumors: correlation with clinicopathological features and prognostic value.

BACKGROUND: Methylation of the CpG islands in the p16 gene promoter region is an important transcription repression mechanism that has been identified as an alternative mechanism for inactivating specific genes in cancer. Given that, DNA methylation is a common event in colorectal cancer. MATERIALS AND METHODS: The aim of this study was to establish the methylation status of the p16 gene in 104 patients with colorectal carcinoma and evaluate its prognostic value. DNA was bisulfite-modified and analyzed for p16 promoter methylation by methylation-specific PCR. RESULTS: Methylation of thep16 gene was determined in 18.3% of our patient population (19/104). The methylated state did not correlate with any clinicopathological factors. During a median follow-up period of 72 months, the overall survival rate for patients with gene methylation was 75% and without gene methylation it was 61% (p = 0.09). CONCLUSIONS: Although not statistically significant, this difference indicates a clinically valuable tendency.

Adult↗

PubMed2003

Nonlinear mechanical response and rippling of thick multiwalled carbon nanotubes.

The measured drop of the effective bending stiffness of multiwalled carbon nanotubes (MWCNTs) with increasing diameter is investigated by a generalized local quasicontinuum method. The previous hypothesis that this reduction is due to a rippling mode is confirmed by the calculations. The observed ripples result from a complex three-dimensional deformation similar to the Yoshimura buckling pattern. It is found that thick MWCNTs exhibit a well-defined nonlinear moment-curvature relation, even for small deformations, governed by the interplay of strain energy relaxation and intertube interactions. Rippling deformations are also predicted for MWCNTs subject to torsion, resulting in an effective torsional modulus much smaller than that predicted by linear elasticity.

Journal Article↗

PubMed2003

Potential use of antioxidants for control of growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on whole maize grain.

The effect of interactions between two food grade antioxidants butylated hydroxyanisole (BHA) and propyl paraben (PP, 100, 200, 500 microg g(-1)) and water activity (a(w), 0.995, 0.98, 0.95) of irradiated maize on lag phase prior to growth, growth rate and fumonisin production by Fusarium verticillioides and Fusarium proliferatum was evaluated at 25 degrees C. Both antioxidants had an effect on growth characteristics, and fumonisin production. However, this was dependent on the dose used and the a(w) treatment. At 500 microg g(-1) BHA and PP increased the lag phase prior to growth, and reduced the growth rate of both Fusarium species significantly, especially at 0.95 a(w). Both antioxidants significantly reduced the production of fumonisin by both Fusarium species, especially at 0.98 and 0.95 a(w). These results suggest that these antioxidants have potential for treatment of maize grain for controlling growth of these mycotoxigenic species and prevent fumonisin accumulation.

Antioxidants↗

PubMed2002

Biotechnological applications of penicillin acylases: state-of-the-art.

This review describes the most recent developments in the biotechnological applications of penicillin acylases. This group of enzymes is involved mainly in the industrial production of 6-aminopenicillanic acid and the synthesis of semisynthetic beta-lactam antibiotics. In addition, penicillin acylases can also be employed in other useful biotransformations, such as peptide synthesis and the resolution of racemic mixtures of chiral compounds. Particular emphasis is placed on advances in detection of new enzyme specificities towards other natural penicillins, enzyme immobilization, and optimization of enzyme-catalyzed hydrolysis and synthesis in the presence of organic solvents.

Anti-Bacterial Agents↗

PubMed2001

[Analysis of a programme of direct referral between primary and specialist care in potential surgery patients].

OBJECTIVE: To describe the results of a programme of direct referral of potential surgery patients between primary and specialist care, designed to lessen waiting-times.Design. Prospective, longitudinal and descriptive study. SETTING: Health Area N. masculine 19 (Valencian Health Service): Surgery Service of Elche Hospital and 6 Health Centres. PARTICIPANTS: Patients with pathologies that do not need special techniques for diagnosis except examination and who have a clear irrefutable indication of surgery without risk factors (ASA I-II).Intervention. The referral protocol consists of: a) diagnosis of pathology and pre-operative study in primary care (PC); b) appointment made by phone for the surgery clinic at the hospital, where diagnosis and pre-operative study are confirmed; c) referral and operation in the unit of non-hospital major surgery (UCMA); d) monitoring post-operation by the home hospitalisation unit (HHU) or preferably by the health centre, and e) check-up at the surgery clinic. Main measurements. The degree of agreement between PC and the specialist, assessment of the pre-operative study, and waiting time. RESULTS: 86 patients were referred (average age, 35; 76% male) by 28 doctors. The most common pathologies were hernia (36%), pilonidal sinus (23.2%) and miscellaneous (32.5%). There was general agreement in diagnosis in 90.7% of cases. 89.5% of patients brought the proper pre-operative study. Mean waiting time between the primary care consultation in the different procedures and the first hospital consultation was 19 days; with 44 more days elapsing till the surgical operation. CONCLUSIONS: This new programme is effective and economic, in that there is < > of patients, waiting time is reduced by over 7 months for pilonidal sinus and by over 2 years for hernia pathology, and the procedure can be used for a large number of patients, as the pathologies involved are very common.

Adolescent↗

PubMed2001

Clinical, manometric, and EMG characteristics of patients with fecal incontinence.

Fecal incontinence occurs frequently in both men and women. Yet, few studies on fecal incontinence have separated the evaluation and interpretation of data by gender. This study was designed to identify differences in the clinical, anorectal manometry, and electromyography (EMG) characteristics between male and female patients with fecal incontinence. We compared 53 incontinent males (mean age, 64 years) with 72 incontinent females (mean age, 61 years). Each patient underwent computerized anorectal manometry, and invasive (pudendal nerve conduction studies and concentric needle EMG) and noninvasive EMG (anal sensor surface electrode). An anal incontinence score (AIS) ranging from 0 to 6 was used to categorize patients. Male patients had higher incontinence scores at presentation (AIS greater than 4, 70% vs. 54%). Female patients had significantly lower resting pressure (40 vs. 53 mmHg, p < 0.05) and more women had sphincter asymmetry (36% vs. 25%, p < 0.05). Both groups had similar PNTMLs (2.41 vs. 2.47 ms). Difference was seen in the net strength of the sphincter (women 4.0 microV vs. men 8.0 microV, p < 0.05), as measured by noninvasive EMG. In conclusion, it is well known that there are differences in anorectal physiologic function between male and female patients with normal continence. Comparing male and female patients with fecal incontinence suggests that female patients tend to have worse sphincter function that men. Both groups had similar EMG alterations, suggesting a common neurogenic injury as etiology. Future studies are needed to address the sexes separately.

Adult↗

PubMed2001

Comparison of dietary intake among overweight and non-overweight schoolchildren.

OBJECTIVE: To determine differences in dietary intake between overweight and non-overweight schoolchildren and differences in consumption during the day and in the course of the week. RESEARCH METHODS AND PROCEDURES: Using a cross-sectional design, 32 schoolchildren (11-y-old) were selected at random. The parents of children recorded dietary intake for a week using the food weighing method. The children were considered to be overweight when the weight for height was higher than 90th percentile. RESULTS: Some 46.9% of examined schoolchildren were considered overweight. Percentage energy intake reported was significantly lower in the overweight group compared to the non-overweight children (8948.7 vs 9590.1 kJ/day; P<0.01). Carbohydrate intake was significantly greater in the non-overweight schoolchildren (250.9+/-58.8 vs 222.1+/-77.4 g/day; P<0.01). The difference in protein intake between week and weekend days was significant (81.6+/-25.5 in the week days vs 73.9+/-21.4 g/day in the weekend days; P<0.05). DISCUSSION: The data suggest the belief that overweight children eat more than non-overweight children is not correct. These findings suggest that the positive energy balance causing overweight is due possibly to a low energy output.

Child↗

PubMed2001

Subcutaneous emphysema during labour.

Subcutaneous emphysema is an unusual but potentially dangerous complication of pregnancy and labour. The incidence is unknown. About 200 cases have been reported in world literature, mainly in primiparous women. This report describes a 30-year-old primigravid who complained during labour of a sudden swelling in her face associated with a mild difficulty in breathing.

Journal Article↗

PubMed2001

Variability of six STR loci in populations from Central Spain.

Allele frequency distributions of six short tandem repeat (STR) loci, HUMTH01, HUMFES/FPS, HUMTPOX, HUMVWF/A31, HUMF13B, and HUMLPL, were determined in a population (101 individuals) of the Vera-Jerte region in West Central Spain. Amplified products were electrophoresed on denaturing polyacrylamide gels and silver-stained. The exact test demonstrated that none of the six loci deviated from Hardy-Weinberg equilibrium. R-matrix analysis in relation to other European samples agrees well with genetic distance results of Reynolds et al. (1983). Comparisons show that our population comes reasonably well within the range of variation of other European samples, and that the representation of these samples on the genetic map indicates a close relation between geographical location and distribution in the diagram.

Alleles↗

PubMed2001

Evaluation of Persian Gulf veterans with symptoms of peripheral neuropathy.

BACKGROUND: Persian Gulf syndrome is a set of symptoms that do not fit into well-understood diagnostic categories. Among these symptoms, there are some that could suggest a generalized neuropathic process. OBJECTIVE: Correlate neurological symptoms with objective electrodiagnostic findings. METHODS: A randomized sample of 176 Persian Gulf veterans (PGV) evaluated at the San Juan Veterans Administration Medical Center was obtained. The subjects completed a questionnaire, and those who met the inclusion criteria underwent electrodiagnostic evaluation. RESULTS: Of the 176 PGV selected, 162 completed the questionnaire. The next step was to perform electrodiagnostic studies on those who described symptoms suggesting peripheral neuropathy and met the inclusion criteria. Twelve individuals met the inclusion criteria for electro-diagnostic studies. All studies were normal except that two subjects were found to have bilateral carpal tunnel syndrome. CONCLUSIONS: Although this is a relatively small sample of PGV, the findings are in accordance with other studies in which no definite generalized neuropathic pattern has been described.

Adult↗

PubMed2001

Construction of a reference linkage map for melon.

A map of melon (Cucumis melo L.) with 411 markers (234 RFLPs, 94 AFLPs, 47 RAPDs, 29 SSRs, five inter-SSRs, and two isozymes) and one morphological trait (carpel number) was constructed using the F2 progeny of a cross between the Korean accession P1161375 and the Spanish melon type 'Pinyonet Piel de Sapo'. RFLPs were obtained using 212 probes from different genomic and cDNA melon libraries, including 16 Arabidopsis ESTs, 13 Cucumis known genes, and three resistant gene homologues. Most loci (391) mapped to 12 major linkage groups, spanning a total genetic distance of 1197 cM, with an average map interval of 3 cM/marker. The remaining 21 loci (six RAPDs and 15 AFLPs) were not linked. A majority (66%) of the markers were codominant (RFLPs, SSRs, and isozymes), making them easily transferable to other melon crosses. Such markers can be used as a reference, to merge other melon and cucumber maps already constructed. Indeed, some of them (23 SSRs, 14 RFLPs, one isozyme, and one morphological trait) could act as anchor points with other published cucurbit maps.

Chromosome Mapping↗

PubMed2000

Cocaine self-administration in rats differentially alters mRNA levels of the monoamine transporters and striatal neuropeptides.

The potential neuroadaptations to cocaine self-administration (SA) were evaluated using quantitative in situ hybridisation histochemistry. Levels of mRNAs of the monoamine transporters, i.e. the primary molecular targets of cocaine, and the striatal neuropeptides substance P and enkephalin, which predominantly exist in different populations of dopaminoceptive striatal neurons, were quantified in rats which had reached different stages of acquisition of cocaine SA. Thus, animals were killed 1 h after completing a self-administration session (i) early in or after acquisition of cocaine SA (ii) after various regimes of chronic cocaine SA, and (iii) a 10-day period of withdrawal from chronic cocaine intake. Control mRNA levels of all molecules under study were those quantified in animals receiving i.v. saline yoked to rats self-administering cocaine (1.5 or 0.75 mg/kg per infusion, depending on the experiment). Monoamine transporter expression was differentially altered by cocaine; dopamine transporter mRNA levels in the ventral tegmental area, but not in the substantia nigra, were increased following withdrawal from cocaine, suggesting a role for the upregulated mesolimbic dopamine transporter in the mechanisms underlying relapse to cocaine taking. By contrast, serotonin transporter mRNA in the dorsal raphé and noradrenaline transporter mRNA in the locus coeruleus remained unaltered under all experimental conditions. In addition, the expression of the striatal neuropeptides was also differentially altered; substance P mRNA levels were transiently increased in the shell of the nucleus accumbens by prolonged cocaine self-administration, but enkephalin mRNA levels in the dorsal and ventral striatum remained unaltered under all conditions.

Animals↗

PubMed2000

Prediction of penicillin V acylase stability in water-organic co-solvent monophasic systems as a function of solvent composition.

Hydrolytic activity of penicillin V acylase (EC 3.5.1.11) can be improved by using organic cosolvents in monophasic systems. However, the addition of these solvents may result in loss of stability of the enzyme. The thermal stability of penicillin V acylase from Streptomyces lavendulae in water-organic cosolvent monophasic systems depends on the nature of the organic solvent and its concentration in the media. The threshold solvent concentration (at which half enzymatic activity is displayed) is related to the denaturing capacity of the solvent. We found out linear correlations between the free energy of denaturation at 40 degrees C and the concentration of the solvent in the media. On one hand, those solvents with logP values lower than -1.8 have a protective effect that is enhanced when its concentration is increased in the medium. On the other hand, those solvents with logP values higher than -1.8 have a denaturing effect: the higher this value and concentration, the more deleterious. Deactivation constants of PVA at 40 degrees C can be predicted in any monophasic system containing a water-miscible solvent.

Journal Article↗