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Biomedical subjects

R Rodrigues

Publications and source records attributed to R Rodrigues.

At least 19 recordsLinked to original sources
PubMed2002

Osmolality of solutions, emulsions and drugs that may have a high osmolality: aspects of their use in neonatal care.

OBJECTIVE: Administration of some hypertonic substances to neonates has been associated with a variety of adverse effects. This study was conducted to determine the osmolality of intravenous drugs and solutions used in neonates receiving intensive care. METHODS: Osmolality was measured by freezing point depression. Vasoactive drugs, diuretics, anticonvulsants, antimicrobials, and glucose and electrolyte solutions were some of the substances analyzed. RESULTS: The osmolalities of 90 substances were measured; the respective intra-assay and interassay coefficients of variation were always less than 5%. A few drugs were found to be extremely hypertonic (> 8000 mOsm/kg), and most of them contain propylene glycol as vehicle (e.g. digoxin, phenytoin, diazepam and phenobarbital). Other drugs, at the same concentration, evidenced a significant discrepancy of osmolality depending on the trademark. CONCLUSIONS: The finding of some extremely hypertonic drugs highlights the need for further investigation in order to study their potential adverse effects in neonates, as well as to evaluate any advantage in diluting, infusing slowly or even avoiding such substances. Given the fact that there exists a discrepancy in osmolalities in some drugs at the same concentration depending on the trademark, the more isotonic solutions should be the preferred choice for intravenous administration.

Emulsions↗
PubMed2002

Coating of solid-phase microextraction fibers with chemically bonded silica particles: selective extraction of polycyclic aromatic hydrocarbons from drinking water samples.

In this study, solid-phase microextraction fibers coated with modified silica particles (5 pm dp) bonded to methyl (C1), hexyl (C6), octyl (C8), and polymeric octadecyl (C18) groups are prepared and evaluated. Selective extraction of polycyclic aromatic hydrocarbons (PAHs) from river water is used to demonstrate the selective behavior of the fibers as a function of the alkyl chains bonded to the silica phase. Scanning electron micrography suggests that the coating structure consists in a monolayer of particles bonded to the surface of the fiber. The behavior of the fibers upon the extraction of PAHs from water samples is compared with the use of standard polydimethylsiloxane fibers that are commercially available.

Journal Article↗
PubMed2001

Rhizobia of chickpea from southern Portugal: symbiotic efficiency and genetic diversity.

AIMS: In order to evaluate differences between chickpea rhizobial populations from three geographical areas in southern Portugal (Beja, Elvas and Evora), isolates from the three regions were obtained and analysed. METHODS AND RESULTS: The genetic characterization of the isolates was done by plasmid profiles and restriction analysis of the nifH gene. Symbiotic efficiency of the isolates was also determined. Relationships between geographical origin, symbiotic efficiency and molecular characteristics were established. Beja soil revealed a larger rhizobia population as well as the presence of some of the isolates with higher symbiotic efficiency values. Isolates with a single plasmid showed a significantly higher symbiotic efficiency. CONCLUSION: Genetic and phenotypic differences were detected between the natural rhizobial populations from the three locations. SIGNIFICANCE AND IMPACT OF THE STUDY: The different yield potential with cultivars of chickpea usually obtained in the three regions of southern Portugal could be due to their different natural rhizobial populations.

Genetic Variation↗
PubMed2001

Impact of adherence to antiretroviral therapy in HIV-1-infected patients at a university public service in Brazil.

The objective of this study was to assess if a simple evaluation, adherence to antiretroviral therapy, would correlate to clinical and laboratory outcomes. We followed an open cohort of patients from a public teaching hospital AIDS outpatient clinic. Patients were categorized according to adherence as: regular (Reg), optimal, all doses all days, tolerating only irregular timing (+/- 2 hours) of intake; quasi-regular (qReg), those missing up to four doses or 1 full day during a month; irregular (Irreg), all other irregular regimens, and ignored (Ign), those without information. The results from a simple questionnaire were compared to CD4+ cell counts and human immunodeficiency virus type 1 (HIV-1) RNA plasma viremia. One hundred eighty-two HIV-1-infected patients (126 males, 69%; 56 females, 31%) were analyzed. Information on adherence was available for 168 (90%). Reg adherence was reported by 75 (41%) patients, qReg adherence by 35 (19%), and Irreg by 53 (29%) of patients. The main reasons for nonadherence were forgetfulness, intolerance, use of alcohol, and misunderstanding of prescription. A significant increase of CD4+ T-cell counts and absolute gain were only observed among Reg and qReg users (p < 0.001). The median viral RNA load log10 decreases were -1.68, -1.45, -0.9 log, respectively, for Reg, qReg, and Irreg patients (p = 0.043, Kruskal-Wallis). Development of and death from AIDS occurred almost exclusively among those with Ign or Irreg adherence. Previous use of antiretroviral therapy may have had an impact in treatment response. Individuals who were treatment-naive were more likely to be Reg users (41%). Although more refined methods to assess adherence should be implemented when available, the inability to do so should not prevent simple, albeit subjective measurements that also correlate with favorable outcome. Mechanisms to improve adherence should be considered an integral part of antiretroviral therapy.

Adult↗
PubMed2001

Neurological teleconsultation for general practitioners.

A neurology teleconsulting network was implemented between a university hospital in Lisbon and five nearby health centres. PCs equipped for videoconferencing were installed, connected by ISDN lines at 128 kbit/s. Fifty-three general practitioners (GPs) were surveyed. The survey showed that the GPs had difficulties in using computers, but they had definite intentions to use teleconsultation for neurology cases and 83% of the respondents stated that they would probably use the technique. During the study, 90 neurology teleconsultations took place over 55 weeks. The average consultation rate was 1.6 teleconsultations per week (SD 1.3, range 0-6). The conferences lasted 10-45 min. Longer teleconsultations were mainly due to technical difficulties in using computers on the part of users with a low level of computer literacy. The patients were 42 males and 46 females, with a mean age of 38 years (SD 20, range 1-84); two patients were discussed twice. The benefits consisted mainly of advice on patient medication, diagnosis and the prevention of unnecessary specialist consultations or laboratory examinations. Doctor-doctor teleconsultation allows the rapid resolution of queries which otherwise cause stress to patients and increase the cost and complexity of care.

Adolescent↗
PubMed2001

[Type B natriuretic peptide in the diagnosis of heart failure with preserved systolic function].

BACKGROUND: Heart failure (HF) with preserved left ventricular systolic function (LVSF) is observed in up to 50% patients with HF. There is no consensus on non-invasive diagnosis of this entity. OBJECTIVE: Evaluation of B-type natriuretic peptide (BNP) in the diagnosis of HF with preserved left ventricular systolic function. DESIGN: Prospective study. PATIENTS: One hundred and seventy-six consecutive patients with suspected HF were evaluated. Patients were classified as having HF with preserved LVSF, if they had symptoms and signs of HF, an ejection fraction greater than 40% and an abnormal Doppler pattern of the mitral inflow or atrial fibrilation and no other causes for the symptoms. All patients had a 12-lead EKG, chest roentgenogram, simple spirometry, M-mode and 2D echocardiogram with pulsed Doppler study of transmitral inflow and determination of plasma BNP levels. RESULTS: Of the 176 patients, 65 had ejection fraction greater than 40%. Of these patients 46 were classified as having HF with preserved LVSF and 19 as not having HF. Patients with HF and preserved LVSF were older, had a higher systolic blood pressure (SBP), less pathologic Q waves on ECG and higher left ventricular ejection fraction and plasma BNP than patients without HF. Multivariate analysis revealed that BNP and SBP were independently associated with the diagnosis of HF. The accuracy of BNP in the diagnosis of HF with preserved LVSF evaluated by the area under the receiver operating characteristic curve was 0.94. CONCLUSION: These results suggest that the measurement of BNP levels can help clinicians in the diagnosis of HF with preserved LVSF. Whether BNP levels might be used in clinical practice as a test for the diagnosis of HF with preserved LVSF is a question that merits further studies.

Aged↗
PubMed1999

Mimicry of erythropoietin by a nonpeptide molecule.

Erythropoietin (EPO) controls the proliferation and differentiation of erythroid progenitor cells into red blood cells. EPO induces these effects by dimerization of the EPO receptors (EPOR) present on these cells. To discover nonpeptide molecules capable of mimicking the effects of EPO, we identified a small molecule capable of binding to one chain of EPOR and used it to synthesize molecules capable of inducing dimerization of the EPOR. We first identified compound 1 (N-3-[2-(4-biphenyl)-6-chloro-5-methyl]indolyl-acetyl-L-lysine methyl ester) by screening the in-house chemical collection for inhibitors of EPO binding to human EPOR and then prepared compound 5, which contains eight copies of compound 1 held together by a central core. Although both compounds inhibited EPO binding of EPOR, only compound 5 induced dimerization of soluble EPOR. Binding of EPO to its receptor in cells results in activation of many intracellular signaling molecules, including transcription factors like signal transducer and activator of transcription (STAT) proteins, leading to growth and differentiation of these cells. Consistent with its ability to induce dimerization of EPOR in solution, compound 5 exhibited much of the same biological activities as EPO, such as (i) the activation of a STAT-dependent luciferase reporter gene in BAF3 cells expressing human EPOR, (ii) supporting the proliferation of several tumor cell lines expressing the human or mouse EPOR, and (iii) the in vitro differentiation of human progenitor cells into colonies of erythrocytic lineage. These data demonstrate that a nonpeptide molecule is capable of inducing EPOR dimerization and mimicking the biological activities of EPO.

Anemia↗
PubMed1999

Randomized comparison between intravaginal misoprostol and dinoprostone for cervical ripening and induction of labor.

OBJECTIVE: We sought to evaluate the efficacy and safety of intravaginal misoprostol and dinoprostone for labor induction. STUDY DESIGN: One hundred eighty-nine women with singleton term pregnancies and unfavorable cervices were randomly assigned to receive intravaginal misoprostol or dinoprostone. The outcome variables were change in Bishop score, time from application to active phase of labor and delivery, fetal and maternal morbidity, and the incidence of cesarean deliveries. RESULTS: The interval from application of the initial dose to the beginning of the active phase of labor was 9.8 +/- 5.8 and 14.2 +/- 10.2 hours (P <.01), and the interval from initial dose to delivery was 15.3 +/- 9.8 and 19.1 +/- 13.2 hours (P =.027) for the misoprostol and dinoprostone groups, respectively. There were no significant differences in Bishop score change, cesarean delivery rate, and the incidence of tachysystole, hypersystole, and hyperstimulation. No maternal and neonatal adverse effects were noted. CONCLUSION: Intravaginal misoprostol is more effective than intravaginal dinoprostone for labor induction in low-risk patients at term with unfavorable cervices.

Administration, Intravaginal↗
PubMed1999

Vaginal hysterectomy for correcting genital prolapse. Long-term evaluation.

OBJECTIVE: To determine whether a transvaginal hysterectomy with anterior and posterior repair is effective in the long term in treating uterovaginal prolapse and stress urinary incontinence (SUI). STUDY DESIGN: Seventy-four patients subjected to vaginal hysterectomy for the treatment of severe genital prolapse, on average five years before the study, were contacted by letter for evaluation. Four of these patients had died, and 47 (67.1%) responded to the letter. The mean age of the patients at the time of reevaluation was 66.1 +/- 10.6 years, and mean parity was 6.6 deliveries. RESULTS: All patients but two presented some degree of genital prolapse at the time of reevaluation, with three cases of total vaginal vault prolapse. White patients (87.2%) predominated over African (black) patients (12.8%). SUI associated with prolapse persisted in 14 of the 20 patients, and 6 others had this complaint after surgical correction (22.2% of previously continent patients). CONCLUSION: The rate of unsuccessful surgical correction of severe genital prolapse was very high (95.7%), and cure of SUI was low (30%), with SUI actually arising after surgical correction in 25% of continent patients. In addition to parity, there seems to be a racial factor linked to the onset and maintenance of this pathology, with a higher prevalence among white patients.

Aged↗
PubMed1999

Detection of angiographic coronary restenosis after percutaneous transluminal coronary angioplasty (PTCA): usefulness of angina combined with rest electrocardiogram.

PURPOSE: To evaluate the value of recurrent anginal symptoms combined with seriation of conventional EKG in detecting coronary restenosis (renarrowing > or = 50% at the site dilated) after PTCA. Two hundred and seventy patients (204 men, mean age 53.1 +/- 9.4 years) with angina who submitted to successful PTCA of single-vessel coronary disease were followed and restudied angiographically 5.2 +/- 1.6 months after the procedure. At any moment from PTCA to follow-up: 1) typical angina pectoris was classified as either absent or present; 2) a 12-lead EKG was classified as improved, unchanged or worsened in comparison with the EKG either before or early after PTCA on the basis of ST-T alterations; 3) all patients underwent coronariography and were then classified as either having or lacking restenosis. The sensitivity and predictive positive value of recurrent angina, worsened EKG, or both, in detecting restenosis were respectively: 74.6% and 68.6%, 44.3% and 85.3%, and 55.9 and 91.7%. The specificity and predictive negative value of no recurrence of angina, improved EKG, or both, in detecting the absence of restenosis were respectively: 85.8% and 89.1%; 69.6% and 91.0%; and 75.6% and 93.9%. CONCLUSION: In single-vessel coronary disease, the detection of coronary restenosis after PTCA based on behavior of the symptoms plus rest EKG seriation shows acceptable degrees of sensitivity, specificity and mainly of predictive values when comparison with respective historical values of the ergometric test is considered.

Adult↗
PubMed1998

Induction of labor with intravaginal administration of misoprostol.

OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of intravaginal misoprostol for labor induction. METHODS: 110 singleton term pregnancies with or without rupture of membranes were enrolled. Fractionated doses of misoprostol were applied (50-100 microg), every 6 h until a maximum of three doses or beginning of labor. RESULTS: The average interval (+/- S.D.) from vaginal application to the beginning of active labor and to delivery were, respectively, 9.5 +/- 5.7 h and 14.8 +/- 9.5 h. Failed labor induction was observed in two cases (2%). Cesarean section rate was 14%. The incidence of tachysystole was 18% and hypersystole 4%, but these situations were associated with abnormal fetal heart rate pattern (hyperstimulation) in only 3%. No maternal side effects and neonatal adverse effects were noted. CONCLUSIONS: Intravaginal misoprostol administration with low doses is an effective and safe method for labor induction in term pregnancies, with or without rupture of membranes.

Administration, Intravaginal↗
PubMed1997

Line-Mixing Effects in Q Branches of CO2

A theoretical model based on the energy corrected sudden (ECS) approximation is used in order to account for line-mixing effects in Delta left and right arrow Pi infrared Q branches of 12C16O2. Its quality is demonstrated by comparisons with numerous laboratory spectra of CO2-He and CO2-N2 mixtures: three Q branches in the 4 and 17 μm regions are investigated at room temperature in a wide pressure range. The influence of mixing between Q(J) lines associated with odd and even values of the rotational quantum number J is demonstrated and analyzed in detail. It is shown that, in contrast to available fitting law approaches, the ECS model correctly predicts the influence of the parity of the rotational quantum numbers J and J' on coupling between the Q(J) and Q(J') lines. Comparisons between the effects of collisions of CO2 with N2 and He are made and analyzed. They show that these two systems involve different line couplings within the Q branch. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Line-Mixing Effects in Q Branches of CO2

A theoretical model based on the energy corrected sudden (ECS) approximation is used to account for line-mixing effects in infrared Q branches of parallel bands of CO2. Measurements have been made using a tunable difference frequency spectrometer system in a Pi-Pi transition: spectra of the 11(1)1II <-- 01(1)0I Q branch near 3580.3 cm-1 have been recorded at room temperature for CO2-He and CO2-N2 mixtures in the 0.1-1 atm total pressure range. Comparisons of experimental and computed spectra prove the quality of the ECS approach. It is shown that the influence of line mixing on the shape of parallel Q branches is very weak and much smaller than in perpendicular transitions. This result is analyzed in detail and explained in terms of the effects of the vibrational angular momenta on the dipole transition moments and vector coupling coefficients involved in the relaxation operator elements. The effects of collisions of CO2 with N2 and He are compared and discussed. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

[Evoked potentials in neurocysticercosis].

In 25 patients with cysticercosis of central nervous system, classified in two clinical forms, benign and malign, evoked potentials were obtained. Normal exam was found in 9 cases with the benign form. From 4 patients with malign clinical presentations, 2 had multiple abnormalities of the evoked potentials, and F wave alterations (mixed pattern). The authors suggest that this mixed pattern may be indicative of severe prognosis.

Adolescent↗
PubMed1997

From hospital information system components to the medical record and clinical guidelines & protocols.

This paper introduces an ongoing project towards the development of a new generation HIS, aiming at the integration of clinical and administrative information within a common framework. Its design incorporates explicit knowledge about domain objects and professional activities to be processed by the system together with related knowledge management services and act management services. The paper presents the conceptual model of the proposed HIS architecture, that supports a rich and fully integrated patient data model, enabling the implementation of a dynamic electronic patient record tightly coupled with computerised guideline knowledge bases.

Clinical Protocols↗
PubMed1997

[Silent ischemia].

The state of art in the treatment of silent myocardial ischemia is reviewed in such a way as to provide with the cardiologist information for the correct decision to be made in patients with ischemia, but without clinical symptoms of angina and its equivalents. Previewed-required, the concept, the classification and the diagnostic methods were reviewed. The prognosis, pharmacological treatment, intervention procedures and their results on the natural history of the disease are emphasised. It is recommended that the treatment of silent ischemia be done, at first, with primary and secondary prevention, and with pharmacological therapy. It is assumed that with the reduction of general ischemic episodes, survival can be individualized. New techniques have been introduced that modify the results in both the short and long term of these procedures.

Cardiovascular Agents↗