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Biomedical subjects

R Ruiz

Publications and source records attributed to R Ruiz.

At least 37 records · Page 2Linked to original sources
PubMed2001

Relationships between heart rate variability, functional capacity, and left ventricular function following myocardial infarction: an evaluation after one week and six months.

BACKGROUND: Relationships between heart rate (HR) variability and different prognostic markers such as ejection fraction, functional capacity, and patency of the infarct-related artery, as well as the comparison of their time courses are not fully elucidated. HYPOTHESIS: The aim of study was to assess prospectively the early postinfarction changes in HR variability and its evolution over a period of 6 months: the relationships between HR variability and functional capacity in exercise testing; left ventricular function in cardiac catheterization: status of the infarct-related artery; and the comparison of their time courses. METHODS: In 42 patients with anterior myocardial infarction, a study was made of the early changes in HR variability analyzed by the complex demodulation method, its evolution over a period of 6 months. and the relationships between HR variability and (1) functional capacity in exercise testing, (2) left ventricular function in cardiac catheterization, and (3) status of the infarct-related artery. RESULTS: At 1 week HR variability parameters correlated directly with functional capacity indicators such as METS, percent change in HR from rest to peak exercise (%deltaHR), difference between initial and peak HR (HR range), percent peak theoretical HR (% peak HR), left ventricular ejection fraction (EF), and, inversely, with end-systolic volume (ESV). Stepwise multiple regression analysis to establish HR variability parameters (recorded at 1 week) as related to functional capacity and left ventricular function at 1 week and 6 months postinfarction established the following variables: (1) At 1 week: standard deviation (SD) of the RR cycles in relation to %deltaHR (r = 0.60, p <0.0001), HR range (r = 0.43, p < 0.01), and EF (r = 0.79, p < 0.0001). (2) At 6 months, the sole accepted HR variability parameter was the SD in relation to %deltaHR (r = 0.38, p < 0.05) and HR range (r = 0.45, p < 0.01). No variability parameter was accepted in relation to METS, % peak HR, or ESV. Relationship between EF or ESV and HR variability parameters was not significant when both were evaluated at 6 months. At that time, there was a significant increase in all HR variability parameters among all surviving patients (n = 39), with the exception of the LF/HF ratio and mean RR cycle. The percent increase in HR variability between the first week and 6 months was greater among those patients with the lowest basal EF. No relation was established between HR variability and patency of the infarct-related artery. CONCLUSION: The decrease in HR variability observed following myocardial infarction is associated with a diminished functional capacity and an increased alteration of the EF. This does not affect the recovery of HR variability, which was observed in all surviving patients.

Adult↗
PubMed2001

4-hydroxy-2-nonylquinoline: a novel iron chelator isolated from a bacterial cell membrane.

The membrane associated iron chelator of Pseudomonas aeruginosa has been extracted from membranes of iron-rich cells with ethanol and purified by reverse phase HPLC. Using 13C NMR and FAB mass spectroscopy, the structure of the chelator has been determined to be 4-hydroxy-2-nonylquinoline. This compound has been previously isolated and named pseudan IX, a name which we use here. We synthesized pseudan IX and show that the spectral properties of the synthesized compound and the purified compound are nearly identical. Also purified from the ethanol extract of membranes is 4-hydroxy-2-heptylquinoline, i.e., pseudan VII. Bacterially purified pseudan IX binds iron as indicated by the incorporation of radiolabeled iron into the chelator and by the formation of pink micelles in a concentrated ethanol extract. The formation of pink micelles upon addition of iron to the synthesized compound indicates that it binds iron.

Chromatography, High Pressure Liquid↗
PubMed2001

[Safety and efficacy of an early deambulation protocol after PTCA with an angio-seal device].

INTRODUCTION: In order to assess the efficacy and safety of an early deambulation (1-2 h) protocol after coronary angioplasty using the Angio-seal collagen plug, we analyzed a consecutive series of patients treated with this device versus a reference group treated with mechanical compression. PATIENTS AND METHODS: Two hundred and seven coronary angioplasty patients were included from February to August 2000. Ninety-eight were treated with mechanical compression and one hundred and nine with the Angio-seal collagen plug. All patients were followed at discharge and fifteen days after surgery. RESULTS: Eighty percent of the patients receiving the Angio-seal device achieved immediate hemostasis (< 1 min). In patients with mechanical compression hemostasis was achieved within 30 min in 68.3%, whereas 25.5% of patients required more than 40 min. First deambulation in the Angio-seal group was achieved within 2 h in 94.5% of the patients. The incidence of major complications was low in both groups (1 case in the Angio-seal group and 2 in the C-clamp group) without statistically significant differences. The Angio-seal group showed a lower incidence of overall vascular complications as compared to the C-clamp group (4.6% vs. 14.3%; p = 0.02). CONCLUSION: Following our protocol, an early deambulation strategy after coronary angioplasty with the use of the Angio-seal collagen plug was feasible, safe and efficacious.

Adult↗
PubMed2001

[Acute severe pain in emergencies. The key for efficient analgesia].

OBJECTIVE: To measure severe acute pain (SAP) frequency, to describe SAP management and to bring to view the conditions of analgesia success in emergency medicine. DESIGN: Multicentre prospective survey: 7 days in Emergency Departments (ED), 30 days in Mobile Intensive Care Units (MICU). Multivariate analysis to measure the independent effect on pain relief of factors identified by Chi squared test. SETTING: All of 6 ED and 8 MICU of a French region. PATIENTS: Over 15 years of age. MAIN OUTCOME MEASURES: Pain intensity was assessed with Visual Analog Scale (VAS) before and after ED or MICU management. SAP group (defined by initial VAS score > 40 mm) was analyzed for pain relief (defined by final VAS score < or = 40 mm). Influence on pain relief through pain aetiology, initial pain intensity, treatment delay and opioid use was analyzed. RESULTS: 1,082 fulfilled medical forms for 3,419 eligible patients. SAP frequency was estimated 36% (CI95 = 34-38%) in ED and 29% (CI95 = 25-33%) in MICU. SAP (n = 368) was often persistent: 45% (CI95 = 43-47%) after discharge from ED and 26% (CI95 = 22-30%) after MICU intervention. The prognostic factors of pain control success revealed by Chi squared test were: MICU (vs ED), treatment delay < or = 3 hours (vs > 3 hours), opioid use (vs non opioid use) and VAS pain level < or = 70 mm (vs > 70 mm). The last 3 factors were confirmed by multivariate analysis. Treatment delay, opioid use, and pain level were found to be determinants of efficient analgesia for SAP. CONCLUSION: Despite the high frequency of SAP in ED and MICU, pain control is not satisfying. Opioid use and early treatment are determinant in analgesia efficiency for SAP and should be therefore encouraged to improve pain relief in emergency medicine.

Acute Disease↗
PubMed2001

"Juvenile" xanthogranuloma: an immunophenotypic study with a reappraisal of histogenesis.

The non-Langerhans histiocytoses, a nosologic category to which juvenile xanthogranuoma (JXG) belongs, represent a heterogenous collection of disorders related to the monocyte/macrophage lineage. The dermal dendrocyte was previously proposed as the cell of origin for JXG on the basis of Factor XIIIa reactivity, a suggestion that does not fully explain the occasional xanthogranulomatous proliferations localizing exclusively to extracutaneous sites. This study applies a panel of recently developed immunohistochemical markers to JXGs and relates the phenotype of this process to new concepts of monocyte/dendritic cell ontogeny. Twenty-seven JXG, ten dermatofibromas (DF), and ten age-matched normal skin specimens were stained using standard immunohistochemistry methods, and all JXGs were fascin+ and CD68+, although 26 of 27 were reactive for HLA-DR, 25 of 27 for Factor XIIIa, 25 of 27 for LCA, 21of 27 for CD4, and 8 of 27 for polyclonal s100. Six of those eight polyclonal S100+ cases were also reactive for monoclonal S100. None of those cases was reactive for CD1a, CD3, CD21, CD34, or CD35. Eight of ten dermatofibromas were FXIIIa+; all were negative for HLA-DR, LCA, CD4, and polyclonal s100. In controls, fascin+ dendritic cells were present but did not stain for Factor XIIIa, S100, or CD4. Based on the morphologic and phenotypic overlap of the lesional cells in JXGs and plasmacytoid monocytes, it would appear that the plasmacytoid monocyte might be considered the putative normal counterpart of the major cellular population of JXGs, a proposal that helps explain the extra-cutaneous, visceral, and soft tissue location that have been reported for occasional cases of JXG. We would also conclude that neither Factor XIIIa-nor S100+ results should preclude the diagnosis of JXG, and find that reactivity for CD4 and LCA may be used to distinguish JXG from DF when the latter is heavily lipidized or the former is not.

Adolescent↗
PubMed2001

Effect of monensin on the performance and nitrogen utilization of lactating dairy cows consuming fresh forage.

We conducted a lactation trial with a fresh forage diet in order to evaluate 1) the effects of monensin on nitrogen metabolism, and 2) the Cornell Net Carbohydrate and Protein System (CNCPS). Thirty Holstein cows in midlactation (eight fitted with ruminal fistulas) were gradually introduced to a fresh forage diet. A concentrate mix based on corn meal was fed before the a.m. and p.m. milking times 0730 and 1730 h, then the fresh forage was fed at 0830 and 1830 h. Fifteen cows each were allocated to a control (no monensin) and a treatment group receiving 350 mg/cow per day of monensin in the p.m. concentrate feeding. A 7-d fecal and urine collection period and a 3-d rumen sampling period were conducted with the fistulated cows. After the lactation study was concluded, the fistulated cows were fed forage regrowth and a 3-d rumen sampling period was repeated. Monensin increased milk production by 1.85 kg. Milk fat and protein concentrations decreased and milk fat and protein yields increased, but the effects were nonsignificant. Monensin did not significantly affect DMI. Ruminal ammonia and the acetate-to-propionate ratio decreased with the addition of monensin in both fed forages. Monensin decreased fecal N output, and increased apparent N digestibility by 5.4%. Because of the decrease in ruminal ammonia and increase in apparent N digestibility, we concluded monensin was sparing amino acids from wasteful rumen degradation with a fresh forage diet. The precision of the CNCPS in predicting performance was high (r2 = 0.76), and the bias was low (overprediction of 3.6%). These results indicate that the CNCPS can be used for dairy cows consuming fresh forage and gives realistic predictions of performance.

Acetates↗
PubMed2000

Efficacies of BCG and vole bacillus (Mycobacterium microti) vaccines in preventing clinically apparent pulmonary tuberculosis in rabbits: a preliminary report.

Tuberculosis (TB) kills more people in the world today than any other infectious disease, and the number of drug-resistant Mycobacterium tuberculosis isolates is increasing. Vaccines, better than most of the currently available strains of bacille Calmette-Guérin (BCG), are urgently needed to control this disease. TB in rabbits resembles human TB more closely than TB in any other common laboratory animal and a most pertinent method of assessing vaccine efficacy is Lurie's tubercle count method in this species. Vaccinated and control rabbits were infected by aerosol with virulent human-type tubercle bacilli (H37Rv). At necropsy 5 weeks thereafter, the grossly visible primary tubercles in the entire lung were counted. A decrease in the number of such tubercles is a quantitative measure of vaccine efficacy: An effective vaccine prevents microscopic tubercles from growing to grossly visible (clinically apparent) size. The Pasteur substrain of BCG and two substrains of Mycobacterium microti (the vole bacillus) reduced the number of visible primary tubercles an average of 75%, whereas three other substrains of BCG and three other substrains of vole bacilli only reduced the number an average of 40%. These initial studies indicate that Lurie's tubercle-count method in rabbits is a precise way to choose the best available tuberculosis vaccines.

Animals↗
PubMed2000

Extraction of natural complex phenols and tannins from grape seeds by using supercritical mixtures of carbon dioxide and alcohol.

Proanthocyanidins are supposed to have some therapeutical properties as antioxidants and antineoplasics. Most of the proanthocyanidins, however, are not commercialized since their separation from natural sources is either very expensive or not well-known. In this work, the feasibility of application of mixtures of carbon dioxide and alcohol under supercritical conditions for selective extraction of some phenolic compounds from grape seeds has been studied, among them some low polymerized proanthocyanidins, their main monomer units, (+)-catechin and (-)-epicatechin, and some low molecular weight phenolic compounds, like gallic acid. An analytical-scale supercritical fluid extractor, whose operation was previously optimized, was used to carry out the experiments. A commercial concentrate of complex phenols and tannins from grape seeds was subjected to supercritical extraction in order to find the best operation conditions before directly extracting defatted milled grape seeds. The solvent capacity was found to increase with pressure and with the amount of alcohol used as cosolvent as expected. Such variation in solvent capacity could be used for design of a selective separation process where individual phenolic compounds or groups of them could be obtained. HPLC coupled with two types of detectors, diode array and mass spectrometry, was used for tentative identification and quantification of complex phenols and tannins in the extracts and in the raw materials used for extraction.

Alcohols↗
PubMed2000

Transcription activation by a variety of AraC/XylS family activators does not depend on the class II-specific activation determinant in the N-terminal domain of the RNA polymerase alpha subunit.

The N-terminal domain of the RNA polymerase alpha subunit (alpha-NTD) was tested for a role in transcription activation by a variety of AraC/XylS family members. Based on substitutions at residues 162 to 165 and an extensive genetic screen we conclude that alpha-NTD is not an activation target for these activators.

Bacterial Proteins↗
PubMed2000

An active contour model algorithm for tracking endocardiac boundaries in echocardiographic sequences.

The use of active contour models to track the boundaries of anatomic structures in medical images is a technique that has attracted a great number of efforts during the last decade. Segmentation techniques based in deformable active contours were proposed first by Kass et al. Because of the problems appearing using these models, some solutions have been introduced, such as balloon force or Gradient Vector Flow force (GVF), derived from the Gradient Vector Flow vectorial field. Results obtained with these forces in the tracking endocardiac task in echocardiographic sequences were not adequate. We have designed a new external force called hybrid force, which, by combining both forces, joins the main features of each one.

Algorithms↗
PubMed2000

Comparison of models for describing the lactation curve of latxa sheep and an analysis of factors affecting milk yield.

The objectives of this work were 1) to compare the goodness-of-fit of empirical models of the lactation curve and 2) to analyze the factors affecting the shapes of the lactation curves, the parameters describing them, and the overall milk yield of Latxa dairy sheep. A total of 14,699 records from 2711 ewes, collected during three consecutive years (1995 to 1997) by the milk recording program of the Latxa ewe of the Basque Country (Spain), were used. Six mathematical models and three fitting procedures were compared. The estimation of model parameters by nonlinear fitting procedures was superior to that by linear regression methods. A nonlinear variable decay model fitted the data better than the other models, as judged by lower mean square prediction error, residual sums of squares, and a lack of first-order positive autocorrelation as assessed by the Durbin Watson coefficient. The effects of the flock, flock-year interaction, month of lambing, length of lactation nested within month of lambing, parity, and number of live lambs born had significant effects on the parameters of the model and the total milk yield (P < 0.01). The prediction of milk yield from the selected model was similar to the estimates obtained with the Fleischmann method currently used by the national breeding program for the Latxa breed.

Animals↗
PubMed2000

An open standard platform for interoperability of medical devices.

Patient care in Intensive Care Units and Operating Rooms requires sophisticated instrumentation for monitoring, treatment and control. A major technical problem is the communication between devices, since the connection of medical devices from different manufacturers has similar problems to the communication between people from different countries who do not share a common language. Several proprietary solutions have been developed by initiatives from well-known international companies. These proprietary, non-open solutions have not gained general acceptability and have failed to draw upon the immense resources for instrumentation development which are available in the industry. Consequently, a set of open European standards for Medical Device Intercommunication has recently been created (ratified 1999) to provide the ability to connect devices to each other freely and to exchange data between them. The development of such standards has lead to the design and implementation of a network platform over which those standards could be tested and validated. At the same time guidelines have been defined for the development and deployment of open solutions for any kind of medical device, including existing legacy devices. The design and testing of this open standards implementation is described in this paper.

Computer Communication Networks↗
PubMed1999

Development of a microparticle-enhanced nephelometric immunoassay for quantitation of human lysozyme in pleural effusion and plasma.

A microparticle-enhanced nephelometric immunoassay, based on polystyrene beads coated with antihuman lysozyme antibody, has been developed for lysozyme quantification in sera and pleural effusions. The standard curve extends from 0.58 mg/l to 18.75 mg/l and no antigen effect was observed. The results showed a good serial precision. The intra-assay precision (n = 20) expressed as CV was between 2.2 and 4.2 in three different concentrations. The inter-assay precision, with different calibration curves (n = 12) was between 6.4 and 7.1. The analytical assay showed a sufficient linearity (r > 0.999). There were no interferences either with haemoglobin (up to 4 g/l), lipids (up to 0.5%, expressed as 1% Lipofundina content), or bilirubin (up to 5 mg/dl). The analytical sensitivity was lower than 0.6 mg/l. The correlation with a Micrococcus lysodeikticus turbidimetric assay showed a correlation coefficient of 0.915. We have studied 92 patients with pleural effusion. In each case, pleural fluid adenosine deaminase activity and pleural fluid to plasma lysozyme ratio were determined. The lysozyme ratio showed similar clinical sensitivity and specificity as to adenosine deaminase.

Adenosine Deaminase↗
PubMed1999

Virulence of Mycobacterium tuberculosis CDC1551 and H37Rv in rabbits evaluated by Lurie's pulmonary tubercle count method.

The virulence of the CDC1551 strain of Mycobacterium tuberculosis was compared to that of H37Rv in a rabbit inhalation model. While rabbits that inhaled the two strains produced equal numbers of grossly visible primary tubercles, CDC1551 tubercles were smaller and contained fewer bacilli than H37Rv tubercles. These findings suggest that a miniepidemic near the Kentucky-Tennessee border caused by CDC1551 was due not to increased virulence but to increased transmissibility.

Animals↗
PubMed1998

[Relationship of increased body weight, androgens, insulin and family history of hypertension with blood pressure in premenopausal women].

BACKGROUND: The aim of this study was to evaluate whether the body weight increased, the androgens, the insulin and the family history of hypertension were independently associated with hypertension. PATIENTS AND METHODS: Sixty-two premenopausal women aged 42 y, whose did not have any situation that change the variables to study: blood pressure, body mass index (BMI) and her increase since age of 20, waist to hip ratio, family history of hypertension, smoking, alcohol, exercise, fasting and after oral glucose tolerance test (GTT) glucose and insulin, sex hormone binding globulin (SHBG), serum and salivary testosterone and the free testosterone index. Hypertension was defined as blood pressure > or = 140/90 mmHg. Multivariate analysis and prevalence odds ratio was calculated. RESULTS: Diastolic blood pressure correlated positively with BMI, waist to hip ratio, increase of BMI, GTT glucose, fasting and GTT insulin, free testosterone index and negatively with SHBG. Systolic blood pressure was only positively correlated with GTT glucose. Into a logistic regression model, the increase of BMI (OR: 1.23; IC: 95%: 1.04-1.5), the family history of hypertension (OR: 7.6; IC 95%: 1.9-29.9) and the free testosterone index (OR: 1.7; IC 95%: 1.1-2.6) were the only variables independently associated with hypertension. The prevalence odds ratio of hypertension according to the presence or not of family history of hypertension decreased when highest increase of BMI was considered. CONCLUSIONS: Higher free testosterone levels with body weight increased in adulthood and family history of hypertension are independent predictors of hypertension in premenopausal women, whereas fasting insulin levels may be related to family history of hypertension.

Adult↗
PubMed1998

Yeast adaptation on softwood prehydrolysate.

Several strains and genera of yeast, including Saccharomyces cerevisiae D5A, Pachysolen tannophilus, S. cerevisiae K-1, Brettanomyces custersii, Candida shehatae, and Candida acidothermophilum, are screened for growth on dilute acid-pretreated softwood prehydrolysate. Selected softwood species found in forest underbrush of the western United States, which contain predominantly hexosan hemicellulose, were studied. This phase of the work emphasized debarked Douglas fir. The two best initial isolates were gradually selected for improved growth by adaptation to increasing prehydrolysate concentrations in batch culture, with due consideration of nutrient requirements. Microaerophilic conditions were evaluated to encourage tolerance of pretreatment hydrolysate, as well as ethanol product. Adaptation and simultaneous saccharification and fermentation (SSF) results are used to illustrate improved performance with an adapted strain, compared to the wild type.

Adaptation, Physiological↗