Search PubMed⌕ Search

Biomedical subjects

R Ruiz

Publications and source records attributed to R Ruiz.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

[Hemorrhagic and edema-forming activity and histologic changes in the mouse footpad induced by venoms from Argentinian Bothrops and Crotalus genuses].

Hemorrhagic, oedema-forming activities and histopathological alterations in the mouse footpad induced by Bothrops and Crotalus snake venoms from Argentina. Hemorrhagic and oedema-forming activities of various Bothrops and Crotalus snake venoms from Argentina were studied, together with histological alterations in the mouse footpad. The highest oedema-forming activity was found in the venom of B. jararaca, followed by B. jararacussu, B. neuwiedii diporus, B. alternatus, and Crotalus durissus terrificus. Regarding hemorrhage, the highest activity was found in the venom of B. neuwiedii diporus, followed by B. jararacussu, B. alternatus, and B. jararaca. No hemorrhage was observed after injection of Crotalus durissus terrificus venom, in agreement with histological observations of injected footpads. Histological analysis revealed a conspicuous inflammatory reaction in the injected footpad, characterized by oedema and an inflammatory infiltrate rich in polymorphonuclear leucocytes. Necrotic blood vessels and dilated lymphatic vessels were observed after injection of B. jararaca and B. jararacussu venoms, and myonecrosis was evident in tissue of mice injected with B. alternatus and B. neuwiedii diporus.

Animals↗
PubMed1998

Alfentanil decreases the excitatory phenomena of sodium methohexital.

STUDY OBJECTIVE: To evaluate the effects of alfentanil or lidocaine on the excitatory phenomena (myoclonus, cough, hiccough) caused by methohexital anesthesia and on the hemodynamic changes induced by retrobulbar block. DESIGN: Prospective, randomized, placebo-controlled, double-blind study. SETTING: University-affiliated, tertiary-care hospital. PATIENTS: 60 ASA physical status II and III patients who were admitted for elective cataract extractions and intraocular lens implantations. INTERVENTIONS: Patients were randomly assigned to one of three groups. After adequate preoxygenation in the holding area, Group 1 received alfentanil 5 micrograms/kg intravenously (i.v.), Group 2 received lidocaine 1 mg/kg i.v. and Group 3 received the placebo (saline) i.v. Immediately after the bolus injection of the study solution, sodium methohexital 1.5 mg/kg was injected i.v. over 30 seconds. As soon as the eyelid reflex was lost, the retrobulbar block was placed over 5 seconds. MEASUREMENTS AND MAIN RESULTS: Occurrences of excitatory phenomena were recorded by an independent observer who was blinded as to treatment allocation. Other side effects such as oculocardiac reflex, nausea, vomiting, itching, or chest wall rigidity were recorded. Vital signs were recorded at baseline and 1, 3, and 5 minutes after placement of the block. In the alfentanil group, the incidence of myoclonus or cough was significantly less than in the lidocaine or placebo groups. Alfentanil also decreased systolic and diastolic blood pressure significantly at 1, 3, and 5 minutes after retrobulbar block. Changes in heart rate were not significantly different from baseline. CONCLUSION: A small dose of alfentanil (5 micrograms/kg i.v.) decreases myoclonus and cough induced by sodium methohexital anesthesia i.v., resulting in improved quality of induction of anesthesia. Alfentanil also attenuates the cardiovascular responses caused by placement of a retrobulbar block.

Adult↗
PubMed1998

Safety profile of WinRho anti-D.

WinRho anti-D is manufactured with multiple processes to minimize the risk of transmitting blood-borne diseases such as viruses. These safety features include donor selection, plasma testing, solvent-detergent viral inactivation, and nanofiltration. To date, there has not been any case of viral transmission in association with use of WinRho anti-D. Adverse drug reactions are infrequent and generally mild; the most common are headache, fever, and chills. Some degree of hemolysis is inevitable due to the mechanism of action of WinRho anti-D, but this is predictable and transient. A few cases of intravascular hemolysis have been reported; hypersensitivity reactions are very rare. WinRho anti-D has been shown in both clinical trials and postmarketing surveillance to be safe and effective in the treatment of idiopathic thrombocytopenic purpura (ITP) and in the prevention of Rh isoimmunization.

Drug Hypersensitivity↗
PubMed1998

[Hernia of the lumbar discs in persons at work. Results of a retrospective study in a series of 189 consecutive patients].

INTRODUCTION: Owing to recent advances in the diagnosis and treatment of lumbar disc pathology, the functional results obtained have improved, although there are still certain factors which affect this. The results in the work place are particularly problematic. OBJECTIVE: With the aim of finding an answer to the problem of relapse of the sciatica syndrome in patients operated on for hernia of the lumbar discs, we describe a study carried out in a consecutive group of patients who had had operations for hernias of lumbar discs whilst at work, within the context of revindication involved in this situation. PATIENTS AND METHODS: We describe the results obtained in a series of 189 patients who had been operated on for lumbar disc pathology. Conventional open surgery was performed in 105 cases. Percutaneous nucleotomy was done in the remainder. In 17.39%, operations were done at more than one level, making a total of 265 discs operated on. RESULTS: These were considered good when the patient returned to his former work. Good results were obtained in 72% of the patients treated by open surgery and 68% of those treated by percutaneous nucleotomy. The re-operation rate was 8.57% for open surgery and 32.14% for percutaneous nucleotomy (p < 0.05). CONCLUSIONS: The main reason for re-operation was a recurrence of disc protrusion. Good results were obtained in 80% of those reoperated. All reoperations were done using open surgery techniques. Overall assessment of the cases, including initial and re-operations, gave good results, reaching 83.59% in the current series.

Adult↗