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Biomedical subjects

F Arias

Publications and source records attributed to F Arias.

At least 19 recordsLinked to original sources
PubMed2006

Xeroderma pigmentosum group D 751 polymorphism as a predictive factor in resected gastric cancer treated with chemo-radiotherapy.

AIM: To evaluate the potential association of xeroderma pigmentosum group D (XPD) codon 751 variant with outcome after chemo-radiotherapy in patients with resected gastric cancer. METHODS: We used PCR-RFLP to evaluate the genetic XPD Lys751Gln polymorphisms in 44 patients with stage III (48%) and IV (20%) gastric cancer treated with surgery following radiation therapy plus 5-fluorouracil/leucovorin based chemotherapy. RESULTS: Statistical analysis showed that 75% (12 of 16) of relapse patients showed Lys/Lys genotype more frequently (P = 0.042). The Lys polymorphism was an independent predictor of high-risk relapse-free survival from Cox analysis (HR: 3.07, 95% CI: 1.07-8.78, P = 0.036) and Kaplan-Meir test (P = 0.027, log-rank test). CONCLUSION: XPD Lys751Gln polymorphism may be an important marker in the prediction of clinical outcome to chemo-radiotherapy in resected gastric cancer patients.

Adult↗
PubMed2004

Activity of Lutzomyia pseudolongipalpis and L. longipalpis s.l. (Diptera: Psychodidae) in Venezuela.

The nocturnal activity of the phlebotomine sandfly Lutzomyia pseudolongipalpis and two populations of L. longipalpis s.l. from different American visceral leishmaniasis foci in Venezuela was studied using collection bottle rotator traps. The activity of L. pseudolongipalpis from Lara State was continuous throughout the night, while that of L. longipalpis s.l. from El Layero, Guárico State and from Santa Ana del Valle, Margarita Island, was greatest before 23:00 h. The activity of sandflies of both populations and sexes steadily decreased thereafter. These different patterns seem to correlate with genetic data that indicate the presence in Venezuela of at least two sibling species in the L. longipalpis complex. The advantages of the bottle rotator trap for this type of study are discussed.

Animals↗
PubMed2004

[Neutropenia and fever in the patient with cancer].

Infection in the immunocompromised host is a serious clinical situation due to its high morbi-mortality and is one of the most frequent complications in the patient with cancer. In patients treated with chemotherapy, the risk of infection basically depends on the duration and intensity of the neutropenia. It is essential to evaluate, the most probable pathogen involved to initiate, a priori, the most suitable treatment, and also to evaluate the general clinical situation of the patient, because from the very beginning the treatment is quite aggressive. Outpatient care is possible for patients at "low risk" of complications. By evaluating the antecedents and clinical history of the patient, through physical exploration and from the data of laboratory and radiological explorations these points can be acknowledged. The early start of broad spectrum antibiotherapy is crucial, and in this chapter we review the most recent therapeutical recommendations.

Clinical Protocols↗
PubMed2004

[Malign obstruction of the superior vena cava].

The present paper offers a review of the malign syndromes of the superior vena cava, their clinical expressions related to the anatomical characteristics of the compartment where the superior vena cava runs, the diagnostic requirements for realising treatment under the best conditions and the ensemble of measures that must be adopted in dealing with this.

Humans↗
PubMed2004

[Acute dysphagia of oncological origin. Therapeutic management].

Dysphagia is one of the most frequent syndromes in patients with tumours of the head and neck, and the oesophagus. This can be the initial symptom or, more frequently, related to the oncological treatment. We review the most important therapeutic and physio-pathological aspects of acute dysphagia of oncological origin. Deglutition is a complex process in which numerous muscular-skeletal structures intervene under the neurological control of different cranial nerves. The complex neuro-muscular coordination needed for a correct deglutition can be affected by numerous situations, both from the effect of the tumours and from their treatment, basically surgery or radiotherapy. In conclusion, it can be affirmed that for a suitable treatment of oncological dysphagia, a correct initial evaluation and an active treatment are required, since not only the patient's quality of life but, on numerous occasions, the possibility of continuing the treatment and thus maintaining the possibilities of a cure depend on control of the dysphagia.

Acute Disease↗
PubMed2004

[Medullar compression].

Medullar compression is an oncological and neurological emergency, whose diagnosis and early treatment are key factors for avoiding severe and irreversible neurological damage. Paralysis, loss of consciousness and alteration in control of the sphincters are the final consequence of the process, and represent an important source of morbidity of the oncology patient, besides being related to a shorter time of survival. The invasion of the vertebral body by haematogenous dissemination is the most frequent cause of medullar compression. On occasions it can create mechanical vertebral instability which represents a real orthopaedic emergency. Pain is the earliest and most frequent symptom. The signs and symptoms appear to the degree that the process advances, passing through motor weakness, alterations in consciousness until paralysis and incontinence of the sphincters are reached, as a result of complete neurological damage. Clinical history and physical exploration should lead to suspicion about the level at which medullar compression is developing, and the most important complementary exploration is MR of the entire spine, which should be requested immediately in order to decide on starting treatment. Treatment is individualised and must be started early. In general, corticoids in combination with radiotherapeutic oncological treatment and/or surgery are the therapeutic weapons to employ.

Humans↗
PubMed2001

Polymorphisms of the repeated sequences in the enhancer region of the thymidylate synthase gene promoter may predict downstaging after preoperative chemoradiation in rectal cancer.

PURPOSE: Thymidylate synthase (TS) is an important target enzyme for the fluoropyrimidines. TS gene promoter possesses regulatory tandemly repeated (TR) sequences that are polymorphic in humans, depending on ethnic factors. These polymorphisms have been reported to influence TS expression. TS expression levels affect tumor downstaging after preoperative fluoruracil (5-FU)-based chemoradiation. Tumor downstaging correlates with improved local control and disease-free survival. The aim of this study is to correlate TR polymorphisms with downstaging and disease-free survival. PATIENTS AND METHODS: Sixty-five patients with rectal cancer underwent tumor resection after preoperative 5-FU-based chemoradiation. Tumor downstaging was evaluated by comparing the pretreatment T stage with the pathologic stage observed in the surgical specimen. TS polymorphism genotype was determined by polymerase chain reaction amplification of the corresponding TS promoter region, and products of amplification were electrophoresed, obtaining products of 220 bp (2/2), 248 bp (3/3), or both (2/3). The TS polymorphism genotype results were subsequently compared with the downstaging observed and with disease-free survival. RESULTS: Patients who were homozygous for triple TR (3/3) had a lower probability of downstaging than patients who were homozygous with double TR or heterozygous patients (2/2 and 2/3): 22% versus 60% (P =.036; logistic regression). Furthermore, a trend toward improved 3-year disease-free survival was detected in the 2/2 and 2/3 groups, compared with that in the 3/3 group (81% v 41%; P =.17). CONCLUSION: This preliminary study suggests that TS repetitive-sequence polymorphisms are predictive for tumor downstaging. TR sequences in TS promoter may be useful as a novel means of predicting response to preoperative 5-FU-based chemoradiation.

Adult↗
PubMed2001

Perinatal outcome, placental pathology, and severity of discordance in monochorionic and dichorionic twins.

OBJECTIVE: To evaluate differences in pregnancy outcomes and placental findings among severely discordant monochorionic and dichorionic twins. METHODS: We studied retrospectively a cohort of 382 twin pregnancies with gestational ages that ranged from 24 to 40 weeks. Pregnancies were classified as dichorionic or monochorionic by histologic examination of placentas. Infants were subdivided into concordant (less than 5% difference in birth weight), mildly discordant (5-25% difference), and severely discordant groups (more than 25% difference), and their clinical characteristics and findings at placental examination were analyzed and compared. RESULTS: Severe discordance occurred significantly more often in monochorionic than in dichorionic twins and was associated with significantly more deliveries before 36 weeks and more newborns remaining more than 10 days in the neonatal intensive care unit. Severely discordant monochorionic and dichorionic twins had significantly worse perinatal mortality and morbidity than mildly discordant and concordant twins. The weight of the placenta of the smaller fetus in severely discordant dichorionic twins with separate placentas and the total placental weight in severely discordant monochorionic twins were significantly smaller than the weights of the placentas in their concordant and mildly discordant counterparts. The umbilical cords of the smaller fetuses in both dichorionic and monochorionic pregnancies exhibited significantly more velamentous insertions and single umbilical arteries than in concordant or mildly discordant twins of similar chorionicity. CONCLUSION: Severe discordance is more frequent and has greater morbidity in monochorionic than dichorionic twins. The most frequent findings in the placentas of severely discordant twins were small placental weight and umbilical cord abnormalities.

Adult↗
PubMed2000

[Sexual dysfunctions induced by serotonin reuptake inhibitors].

OBJECTIVE: To assess the incidence of serotonin reuptake inhibitor (SRI) antidepressant-induced sexual dysfunction (SD) and to compare the sexual side effects of SRI. DESIGN: Naturalistic, prospective, observational study. SETTING: Two urban health centers. PATIENTS: 235 outpatients (164 women, 71 males) who began treatment with some of the following SRI: fluoxetine, sertraline, paroxetine, citalopram and venlafaxine, who had engaged in regular sexual practices with stable partner, who were suffering from different mental disorders who were being treated with SRI. The assignment to each group was according to clinical criteria. INTERVENTIONS: Patients completed questionnaires that allowed reporting of both SD induced by the illness and the treatment, evaluating changes in libido, arousal, and orgasm. The patients were observed over 6 months of treatment. RESULTS: 147 patients (62.6%) reported one or more SD related to SRI treatment. There were differences in the incidence between the different SRI: 39% with fluoxetine, 75.5% with paroxetine, 78.8% with sertraline, 28.9% with citalopram and 80% with venlafaxine. In 78.2% of patients the SD showed no improvement by the end of this period. In a predictive logistical regression model of the presence of SD induced by the SRI, the female category and the presence of previous sexual problems were favourable predictors and the treatment with paroxetine, sertraline or venlafaxine were increased the risk of SD. CONCLUSIONS: SD is one of the most frequent and persistent SRI adverse effect. We recommended to inquiry about SD in patients who were treated with SRI. Significant differences were found in the occurrence of SD between the different SRI. Such data would be particularly valuable to physicians when choosing a specific antidepressant from this therapeutic group.

Adult↗
PubMed2000

Chemoradiotherapy for muscle invading bladder carcinoma. Final report of a single institutional organ-sparing program.

PURPOSE: Chemoradiotherapy is becoming an alternative to radical cystectomy among patients with muscle invading bladder cancer. We began a prospective study in 1988 to determine the possibilities of conservative treatment and aiming to improve the results obtained by cystectomy alone in invasive bladder cancer. A combination of methotrexate, vinblastine, adriamycin, and cisplatin (M-VAC), followed by radiotherapy and concomitant cisplatin was used. METHODS: Fifty patients with good performance status and with stages T2 to T4 operable untreated invasive bladder cancer were entered in the study. Treatment protocol was as follows: (i) cytoreductive transurethral resection; (ii) two cycles of M-VAC chemotherapy; (iii) radiotherapy, 45 Gy on pelvic volume and, at the same time, 20 mg/m(2) cisplatin on days 1 to 5. Cystoscopic evaluation: if there was a complete response, radiotherapy was completed up to 65 Gy; if there was not a complete response, a cystectomy was performed. Median follow-up of the series was 73 months (18-180 m). RESULTS: Tumor response was as follows: 34 complete responses (68%), 9 partial responses (18%), and 7 nonresponses (14%) were observed. The 5-year overall survival and local control were 48% and 47%, respectively. For the complete responder patient, 5-year survival and local control were 65% and 70%, respectively. Severe toxicity was uncommon. The most frequent were leucopenia and cystitis. No treatment-related deaths occurred with either treatment protocol. CONCLUSIONS: Conservative combination treatment may be an acceptable alternative to immediate cystectomy in selected patients with bladder cancer, although a randomized clinical trial would be required to produce definitive results.

Aged↗
PubMed2000

Fabrication of metallic microstructures using exposed, developed silver halide-based photographic film

This paper demonstrates that the pattern of silver particles embedded in the gelatin matrix of exposed and developed silver halide-based photographic film can serve as a template in a broadly applicable method for the microfabrication of metallic microstructures. In this method, a CAD file is reproduced in the photographic film by exposure and developing. The resulting pattern of discontinuous silver grains is augmented and made electrically continuous by electroless deposition of silver, and the electrically continuous structure is then used as the cathode for electrochemical deposition of an additional layer of the same or different metal. The overall process can be completed within 2 h, starting from a CAD file, and can generate electrically continuous structures with the smallest dimension in the plane of the film of approximately 30 microns. Structures with aspect ratio of up to 5 can also be obtained by using the metallic structures as photomasks in photolithography using SU-8 photoresist on the top of the electroplated pattern and exposed from the bottom, followed by development and electroplating through the patterned photoresist. This method of fabrication uses readily available equipment and makes it possible to develop prototypes of a wide variety of metallic structures and devices. The resulting structures--either supported on the film backing or freed from it--are appropriate for use as passive, structural materials such as wire frames or meshes and can also be used in microfluidic, microanalytical, and microelectromechanical systems.

Journal Article↗
PubMed2000

Hyperfractionated radiotherapy concomitant with cisplatin and granulocyte colony-stimulating factor (filgrastim) for laryngeal carcinoma.

An open-label, non-randomized study evaluated the feasibility and efficacy of filgrastim (recombinant methionyl human granulocyte colony-stimulating factor, r-metHuG-CSF) to prevent mucositis induced by accelerated hyperfractionated radiotherapy (1.6 Gy b.i.d., total dose 67.2 Gy in six weeks with a two-week split) and concomitant chemotherapy (cisplatin, 20 mg/m2/day, days 1-5 by continuous intravenous infusion) in patients with laryngeal carcinoma. Filgrastim 300 microg/day was administered on days 1, 3, and 5 in weeks 2-6 of radiotherapy, after the second fraction. Twenty patients (three stage II, six stage III, and eleven stage IV, according to AJCC) were enrolled in the trial. Oral mucosal toxicity was grade 2 in nine patients (45%), grade 3 in eight (40%), and grade 4 in three (15%). Severe hematological toxicity (WHO criteria) was uncommon. Nineteen patients (95%) completed the treatment in the planned time. Overall survival was 55% at three years. The administration of filgrastim with this regimen was feasible, and it appeared to reduce the severity and duration of mucositis induced by the combined treatment.

Adult↗
PubMed2000

Pharmacology of oxytocin and prostaglandins.

Significant advances have been made in the last 20 years in our knowledge about the subcellular events occurring during myometrial contractions and cervical ripening and in the mechanism of action of oxytocin and prostaglandins. These advances have been instrumental in furthering our understanding of the mechanism of action of inhibitors of uterine contractility and have opened the door to clinical trials of agents such as specific COX-II inhibitors that may have the potential to inhibit labor without serious maternal or fetal side effects. There is still a long way to go, however, before all the complex actions of oxytocin and prostaglandins can be understood at a subcellular level, particularly the mechanism of action of prostaglandins in the process of cervical ripening.

Cervical Ripening↗
PubMed1999

Recent advances in the pathophysiology and management of preterm premature rupture of the fetal membranes.

During the past few years, meaningful progress has been achieved in our understanding of the pathophysiology of preterm premature rupture of membranes. In addition, more evidence has been presented in favor of induction and delivery for rupture between 34 and 37 weeks and expectant management for rupture before 34 weeks. New approaches are being suggested to complement expectant management. The purpose of this article is to review this recent information about the pathophysiology and management of women with preterm premature rupture of membranes.

Female↗
PubMed1998

Electrochemical studies of S-nitrosothiols.

S-nitrosothiols (RSNO), such as SNAP, GSNO, and Glc-SNAP-1 exhibited a single, totally irreversible, diffusion controlled reduction peak at potentials of -0.97 V, -0.98 V and -0.91 V, respectively, vs. Ag/AgCl (3 M NaCl) reference electrode. This corresponded to the nitric oxide (NO) release from the S-nitrosothiols. A possible mechanism is proposed for the reduction process.

Electrochemistry↗
PubMed1998

Comparison of the modified biophysical profile to a "new" biophysical profile incorporating the middle cerebral artery to umbilical artery velocity flow systolic/diastolic ratio.

OBJECTIVES: The objective of this study was to determine whether the addition of the middle cerebral to umbilical artery systolic/diastolic velocity waveform ratio to the modified biophysical profile would improve perinatal outcome in patients at high risk. STUDY DESIGN: A prospective, randomized outcome study of patients referred to the perinatal laboratory for antenatal surveillance was undertaken. Six hundred sixty-five patients were randomized to two antenatal surveillance protocols: group 1, modified biophysical profile; and group 2, modified biophysical profile plus evaluation of the middle cerebral artery to umbilical artery systolic/diastolic ratio. Patients were followed up serially and neonatal outcome data including gestational age at delivery, birth weight, incidence of cesarean section delivery for fetal distress, admission to the neonatal intensive care unit, days in the neonatal intensive care unit, and the presence of significant neonatal morbidity were tabulated. RESULTS: The total population showed no statistical difference in outcome parameters between groups 1 and 2. However, a subgroup of patients evaluated for suspected uteroplacental insufficiency did show a significant reduction in caesarean section for fetal distress in group 2 patients. CONCLUSIONS: In a subgroup of patients at risk for uteroplacental insufficiency, the addition of the middle cerebral/umbilical artery ratio to an antenatal surveillance protocol should be expected to improve perinatal outcome.

Adult↗
PubMed1998

Treatment of acardiac twinning.

BACKGROUND: The twin reversed-arterial-perfusion sequence is a complication of monochorionic twin pregnancies characterized by the hemodynamic dependence of a "recipient" twin from a "pump" twin. The recipient twin exhibits lethal abnormalities including acardia and acephaly. The pump twin has a mortality rate of 50% as a result of high-output heart failure. CASE: The blood supply to an acardiac-acephalus twin was interrupted at 24 weeks' gestation using endoscopic laser coagulation. The co-twin was delivered at 35 weeks and had an uneventful neonatal course following correction of a persistent patent ductus arteriosus. Review of the literature reveals 22 cases of acardiac twinning treated with invasive procedures, seven of them using endoscopic laser coagulation. Pump twin mortality with fetal surgery was 13.6% in comparison with 50% mortality with expectant management (P < .001). CONCLUSION: Fetal surgery is the best available treatment for acardiac twinning. Endoscopic laser coagulation at or before 24 weeks and endoscopic or sonographic guided umbilical cord ligation after this gestational age seem to be the best treatments for this condition.

Abnormalities, Severe Teratoid↗