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Biomedical subjects

J M Domínguez

Publications and source records attributed to J M Domínguez.

At least 19 recordsLinked to original sources
PubMed2006

Dexmedetomidine or medetomidine premedication before propofol-desflurane anaesthesia in dogs.

The objective of this study was to evaluate dexmedetomidine as a premedicant in dogs prior to propofol-desflurane anaesthesia, and to compare it with medetomidine. Six healthy dogs were anaesthetized. Each dog received intravenously (i.v.) five preanaesthetic protocols: D1 (dexmedetomidine, 1 microg/kg, i.v.), D2 (dexmedetomidine, 2 microg/kg, i.v.), M1 (medetomidine, 1 microg/kg, i.v.), M2 (medetomidine, 2 microg/kg, i.v.), or M4 (medetomidine, 4 microg/kg, i.v.). Anaesthesia was induced with propofol (2.3-3.3 mg/kg) and maintained with desflurane. The following variables were studied: heart rate (HR), mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate (RR), arterial oxygen saturation, end-tidal CO2, end-tidal concentration of desflurane (EtDES) required for maintenance of anaesthesia and tidal volume. Arterial blood pH (pHa) and arterial blood gas tensions (PaO2, PaCO2) were measured during anaesthesia. Time to extubation, time to sternal recumbency and time to standing were also recorded. HR and RR decreased significantly during sedation in all protocols. Cardiorespiratory variables during anaesthesia were statistically similar for all protocols. EtDES was significantly different between D1 (8.1%) and D2 (7.5%), and between all doses of medetomidine. Desflurane requirements were similar for D1 and M2, and for D2 and M4 protocols. No statistical differences were observed in recovery times. The combination of dexmedetomidine, propofol and desflurane appears to be effective for induction and maintenance of general anaesthesia in healthy dogs.

Anesthesia Recovery Period↗
PubMed2006

Comparison of romifidine and medetomidine pre-medication in propofol-isoflurane anaesthetised dogs.

The objective of this paper was to evaluate romifidine as a pre-medicant in dogs prior to propofol-isoflurane anaesthesia, and to compare it with medetomidine. For this, eight healthy dogs were anaesthetised. Each dog received three pre-anaesthetic protocols: R40 (romifidine, 40 microg/kg, IV), R80 (romifidine, 80 microg/kg, IV) or MED (medetomidine, 10 microg/kg, IV). Induction of anaesthesia was delivered with propofol and maintained with isoflurane. The following variables were studied before sedative administration and 10 min after sedative administration: heart rate (HR), mean arterial pressure (MAP), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) and respiratory rate (RR). During maintenance, the following variables were recorded at 5-min intervals: HR, MAP, SAD, DAP, arterial oxygen saturation (SpO(2)), end-tidal CO(2)(EtCO(2)), end-tidal concentration of isoflurane (EtISO) required for maintenance of anaesthesia and tidal volume (TV). Time to extubation, time to sternal recumbency and time to standing were also registered. HR and RR experimented a significantly decreased during sedation in all protocols respect to baseline values. Mean HR, MAP, SAP, DAP, SpO(2), EtCO(2), and TV during anaesthesia were similar for the three protocols. End tidal of isoflurane concentration was statistically similar for all protocols. Recovery time for R40 was significantly shorter than in R80 and MED. The studied combination of romifidine, propofol and isoflurane appears to be an effective drug combination for inducing and maintaining general anaesthesia in healthy dogs.

Adrenergic alpha-Agonists↗
PubMed2006

Clinical and pathological findings in testis, epididymis, deferens duct and prostate following vasectomy in a dog.

We report the case of a bilateral and multilocular spermatocele and sperm granuloma in a dog that was vasectomized 5 years before. Clinical examination revealed scrotal dermatitis and benign prostatic hyperplasia. Orchiectomy was performed, and gross and histological examination showed testicular degeneration associated with epididymal sperm granuloma. In relation to this case, the literature about long-term effects of vasectomy in dogs has been reviewed. On the basis of these results, a preventive sonogram and physical assessment in prostate and other reproductive structures before vasectomy is recommended.

Animals↗
PubMed2003

A new nuclear magnetic resonance algorithm to determine equilibrium constants of the species in the B(III)-H2O system.

Several efforts have been attempted to study species formation by Nuclear Magnetic Resonance (NMR) in systems with several chemical equilibria present. The majority of these are qualitative and only a few have tried to relate component fractions of a distribution diagram with experimental area fractions determined from NMR spectra to obtain equilibrium constants values. In this work we present a new focus that attempts to relate the species concentration fractions in the system with area fractions beneath NMR peaks to achieve this task. 11B-NMR data of B(III)-H2O systems have been processed with the aid of formation constant values (-log *beta) obtained by potentiometry which are 9.17+/-0.01 for B(OH)3, 9.79+/-0.08 for B2O(OH)5-, 19.90+/-0.09 for B3O3(OH)4- and 38.50+/-0.04 for B5O6(OH)4-, form B(III)-H2O systems with 0.075 M< or = [B(III)]total< or = 0.700 M, in agreement with previous reports and NMR behavior. The treatment of NMR data developed in this work gives a new methodology to obtain formation constants and suggests the possibility to establish a generalization of Beer's law to NMR spectroscopy.

Algorithms↗
PubMed2001

Influence of temperature and pH on xylitol production from xylose by Debaryomyces hansenii.

The production of xylitol from concentrated synthetic xylose solutions (S(o) = 130-135 g/L) by Debaryomyces hansenii was investigated at different pH and temperature values. At optimum starting pH (pH(o) = 5.5), T = 24 degrees C, and relatively low starting biomass levels (0.5-0.6 g(x)/L), 88% of xylose was utilized for xylitol production, the rest being preferentially fermented to ethanol (10%). Under these conditions, nearly 70% of initial carbon was recovered as xylitol, corresponding to final xylitol concentration of 91.9 g(P)/L, product yield on substrate of 0.81 g(P)/g(S), and maximum volumetric and specific productivities of 1.86 g(P)/L x h and 1.43 g(P)/g(x) x h, respectively. At higher and lower pH(o) values, respiration also became important, consuming up to 32% of xylose, while negligible amounts were utilized for cell growth (0.8-1.8%). The same approach extended to the effect of temperature on the metabolism of this yeast at pH(o) = 5.5 and higher biomass levels (1.4-3.0 g(x)/L) revealed that, at temperatures ranging from 32-37 degrees C, xylose was nearly completely consumed to produce xylitol, reaching a maximum volumetric productivity of 4.67 g(P)/L x h at 35 degrees C. Similarly, both respiration and ethanol fermentation became significant either at higher or at lower temperatures. Finally, to elucidate the kinetic mechanisms of both xylitol production and thermal inactivation of the system, the related thermodynamic parameters were estimated from the experimental data with the Arrhenius model: activation enthalpy and entropy were 57.7 kJ/mol and -0.152 kJ/mol x K for xylitol production and 187.3 kJ/mol and 0.054 kJ/mol x K for thermal inactivation, respectively.

Carbon↗
PubMed2001

Association of noninvasive markers of coronary artery reperfusion to assess microvascular obstruction in patients with acute myocardial infarction treated with primary angioplasty.

Early restoration of coronary artery patency through primary angioplasty limits infarct size and improves survival. Increasing evidence, however, suggests that microvascular obstruction is often present despite coronary artery recanalization. This may limit the benefits of reperfusion therapy. We studied the use of noninvasive markers of coronary artery reperfusion as indicators of microvascular obstruction and determinants of prognosis in 98 patients with acute myocardial infarction (AMI) who were successfully treated with primary angioplasty (Thrombolysis In Myocardial Infarction grade 3 flow and residual stenosis <30%). Plasma creatine kinase (CK) levels and 12-lead electrocardiograms were performed on admission, at 90 minutes, and at 6, 12, and 24 hours after treatment. We defined: (1) reperfusion as resolution of ST-segment elevation >50% at 90 minutes, with peak CK levels within 12 hours, and T-wave inversion within 24 hours; and (2) failed reperfusion, as the absence of these parameters. Of the 98 patients studied, 87 (88.8%) had reperfusion and 11 (11.2%) had failed reperfusion. Infarct location was anterior (versus inferior) in 9 patients in the failed reperfusion group (81.8%) compared with 41 patients in the reperfusion group (47.1%) (p <0.01). Congestive heart failure >24 hours after presentation or in-hospital death occurred in 11 patients (12.6%) in the reperfusion group versus 5 (45.5%) in the failed reperfusion group (p <0.01). One-year survival was 96.1% for the reperfusion group and 60.6% for the failed reperfusion group (p <0.0001). We conclude that the association of noninvasive markers of reperfusion better identifies patients with microvascular obstruction among those who had a "successful" primary angioplasty. Evidence of impaired microvascular reperfusion is associated with a poor in-hospital and 1-year outcome.

Aged↗
PubMed2001

Identification of a putative sordarin binding site in Candida albicans elongation factor 2 by photoaffinity labeling.

Candida albicans EF-2 binds sordarin to a single class of binding sites with K(d) = 1.26 microm. Equimolar mixtures of EF-2 and ribosomes, in the presence of a non-hydrolyzable GTP analog, reveal two classes of high affinity sordarin binding sites with K(d) = 0.7 and 41.5 nm, probably due to the existence of two ribosome populations. Photoaffinity labeling of C. albicans EF-2 in the absence of ribosomes has been performed with [(14)C]GM258383, a photoactivatable sordarin derivative. Labeling is saturable and can be considered specific, because it can be prevented with another sordarin analog. The fragment Gln(224)-Lys(232) has been identified as the modified peptide within the EF-2 sequence, Lys(228) being the residue to which the photoprobe was linked. This fragment is included within the G"-subdomain of EF-2. These results are discussed in the light of the high sordarin specificity toward fungal systems.

Amino Acid Sequence↗
PubMed2001

Antioxidant and antimicrobial effects of extracts from hydrolysates of lignocellulosic materials.

The antioxidant and antimicrobial activities of ethyl acetate extracts obtained from acid hydrolysates of several lignocellulosic materials (Eucalyptus globulus wood, barley bran, corn cobs, and corn leaves) were evaluated. The minimum inhibitory and bactericide concentrations (MIC and MBC, respectively) were determined against a selection of bacteria and yeasts. Extracts from Eucalyptus wood hydrolysates were the most active for inhibiting bacteria and yeast growth, with MIC in the range of 10(2)--5 x 10(3) microg/mL and MBC in the range of 10(3)--0(5) microg/mL. Bacteriogenic and bacteriostatic activities of extracts from Eucalyptus wood and barley bran acid hydrolysates were slightly higher than those of corn cobs and leaves. Both the radical scavenging capacity and the inhibition of the beta-carotene bleaching caused by extracts were determined and compared with those of synthetic antioxidants. The antioxidant activity of extracts increased with their concentrations in the media, the stronger properties corresponding to those obtained from Eucalyptus wood hydrolysates.

Acetates↗
PubMed2001

Assessment of the effectiveness of descending aortomyoplasty for nonischemic cardiac failure by means of the subendocardial viability index.

INTRODUCTION: Paraaortic or external aortic counterpulsation is been investigated as a definitive ventricular assistance in cases of terminal congestive heart failure and when heart transplantation is counterindicated. Our aims is to assess the haemodynamic effects of an descending aortomyoplasty in a biological model of congestive heart failure. MATERIALS AND METHODS: As specimens, we used 10 "Large White" pigs. Mean weight was 25,3+/-2,14 Kg. After the administration of conventional anaesthesia, dissection of the latissimus dorsi muscle was performed. Then we performed a thoracotomy at the level of the fourth intercostal space to reach the thoracic aorta. The aorta is dissected 7 centimetres from the output of the subclavia artery and it is wrapped by the dissected muscle. A cardiomyostimulator is provided in order to allow the synchronization between the diastole and the muscle contraction. The model of heart failure was provoked using Verapamil plus Propanolol i.v. RESULTS: A significant increase of the systolic and diastolic aortic pressure (54,2+/-4,05 and 27.5+/-6.77 mmHg versus 76.5+/-6.25 and 56.4+/-5.2 mmHg, p<0,001) and a significant decrease of the left ventricle telediastolic pressures were observed (12.9+/-9 versus 2.6+/-1.57 mmHg, p<0,001). An increase of the cardiac output (0.363+/-0.11 versus 0.846+/-0.08 L/min, p<0,001) and the Subendocardial Viability Index (0.968+/-0.076 versus 1.351+/-0,107, p<0,001)were observed in a model of non-ischemic heart failure. CONCLUSION: Descending Aortomyoplasty as a technique to support circulation in cases of acute heart failure, improves the parameters of ventricular function, aiding the functional recovery of the left ventricle and improving significantly cardiac output as well as diastolic and systolic cardiac pressure. In addition to this, improves the Subendocardial Viability Index in cases of acute heart failure, which indirectly reflects an improvement of the Transmural and Subendocardial Perfusion of the failing heart.

Animals↗
PubMed2001

[Reversible myocardial ischemia in hypothyroidism: Case report].

A silent, reversible myocardial ischemia with normal coronary angiography and reversible with thyroid hormone substitution, has been recently described in hypothyroid patients. We report a 49 years old male with an abnormal exercise electrocardiogram detected in a preventive medical examination. He had laboratory evidence of hypothyroidism and a history of two years of asthenia and progressive coarsening of the voice. The Thallium myocardial perfusion study, showed an alteration of coronary flow during exercise in the septum and lower wall of the left ventricle. Thyroid hormone substitution was started and three months later, a coronary angiography was normal. After six months a repeated Thallium perfusion study and exercise electrocardiogram were informed as normal.

Coronary Angiography↗
PubMed2000

Ethanol production from xylose with the yeast Pichia stipitis and simultaneous product recovery by gas stripping using a gas-lift loop fermentor with attached side-arm (GLSA).

The bioconversion of xylose into ethanol with the yeast Pichia stipitis CBS 5773 is inhibited when 20 g/L of ethanol are present in the fermentation broth. In order to avoid this limitation, the fermentation was carried out with simultaneous recovery of product by CO(2) stripping. The fermentation was also improved by attaching a side-arm to the main body of a classical gas-lift loop fermentor. This side-arm increases the liquid circulation, mass transfer, and gas distribution, reducing the amount of oxygen in the inlet gas necessary to perform the fermentation of xylose under microaerobic conditions (K(L)a approximately 16 h(-1)). The continuous stripping of ethanol from the fermentation broth in this new bioreactor system allowed the consumption of higher xylose concentrations than using Erlenmeyer shaker flasks, improved significantly the process productivity and provided a clean ethanol solution by using an ice-cooled condenser system. Finally, a fed-batch fermentation was carried out with a K(L)a = 15.8 h(-1). Starting with 248.2 g of xylose, 237.6 g of xylose was consumed to produce 88.1 g of ethanol which represents 72.6% of the theoretical yield (47.2 g/L of ethanol was recovered in the condenser, while 9.6 g/L remained in the fermentation broth).

Air Movements↗
PubMed2000

Propofol or thiopentone as induction agents in romifidine-sedated and halothane-N2O-anesthetized dogs: a preliminary study.

The objective of this paper was to evaluate the use of romifidine as a premedicant in dogs before general anesthesia induced with propofol or thiopentone and maintained with halothane-N2O. Fifteen healthy dogs were anesthetized twice. Each dog received, as preanesthetic protocol, atropine (10 microg/kg, IM) and romifidine (40 microg/kg, IM); induction was delivered with propofol or thiopentone and anesthesia was maintained with halothane and N2O for 1 h. Some cardiovascular and respiratory variables and recovery times were recorded. Induction doses of propofol or thiopentone and the percentage of halothane necessary for maintaining anesthesia were also registered. Thiopentone as an induction agent is more respiratory depressive but is less hypotensive than propofol. Thiopentone reduces further the percentage of halothane necessary for maintaining the anesthesia. However, the quality of recovery is poorer, as the time to extubation is longer and the dogs occasionally had a violent recovery. The combination of romifidine, atropine, propofol, halothane, and N2O appears to be an effective combination for inducing and maintaining general anesthesia in healthy dogs.

Anesthesia, General↗
PubMed1999

Sordarin inhibits fungal protein synthesis by blocking translocation differently to fusidic acid.

Sordarin derivatives are selective inhibitors of fungal protein synthesis, which specifically impair elongation factor 2 (EF-2) function. We have studied the effect of sordarin on the ribosome-dependent GTPase activity of EF-2 from Candida albicans in the absence of any other component of the translation system. The effect of sordarin turned out to be dependent both on the ratio of ribosomes to EF-2 and on the nature of the ribosomes. When the amount of EF-2 exceeded that of ribosomes sordarin inhibited the GTPase activity following an inverted bell-shaped dose-response curve, whereas when EF-2 and ribosomes were in equimolar concentrations sordarin yielded a typical sigmoidal dose-dependent inhibition. However, when ricin-treated ribosomes were used, sordarin stimulated the hydrolysis of GTP. These results were compared with those obtained with fusidic acid, showing that both drugs act in a different manner. All these data are consistent with sordarin blocking the elongation cycle at the initial steps of translocation, prior to GTP hydrolysis. In agreement with this conclusion, sordarin prevented the formation of peptidyl-[(3)H]puromycin on polysomes from Candida albicans.

Antifungal Agents↗
PubMed1999

Optimization of L-lactic acid production from glucose by Rhizopus oryzae ATCC 52311.

The effect of nutrients on L(+)-lactic acid production from glucose was investigated using Rhizopus oryzae ATCC 52311. From the shake-flask experiments, the optimal medium composition was defined for improved lactic-acid production. In order to enhance lactic-acid production rate and product yield, controlled aeration in a bubble column was conducted under optimal conditions. Results showed a maximum lactic-acid production rate of 2.58 g/L/h was obtained with an initial glucose concentration of 94 g/L. Final lactic-acid concentration of 83 g/L was achieved after 32 h of fermentation with a weight of 0.88 g lactic acid/g glucose consumed.

Journal Article↗
PubMed1999

Xylitol production from wood hydrolyzates by entrapped Debaryomyces hansenii and Candida guilliermondii cells.

Debaryomyces hansenii cells were entrapped in Ca-alginate beads and used for producing xylitol from wood hydrolyzates. Batch experiments showed that bioconversion was severely hindered when Ca-alginate beads were hardened with Al3+ solutions. As an alternative to Al3+ hardening, the improvements in both mechanical stability of bioparticles and fermenting ability of the immobilized system derived from using increased concentrations of sodium alginate were assessed. The best results were obtained using a 4% (w/v) Na-alginate solution in the gelification step. This concentration was selected to perform continuous fermentations in a packed-bed reactor using raw or charcoal-treated hydrolyzates (15.5 g of xylose/L) with two different yeasts: Candida guilliermondii and Debaryomyces hansenii. With a final cell concentration of about 50 g of cells/L (0.075 g of cells/g of beads), the volumetric productivities reached with these yeasts in media made from charcoal-treated hydrolyzates were 0.58 and 0.91 g/L.h, respectively.

Journal Article↗