Biomedical subjects

D Blanco

Publications and source records attributed to D Blanco.

At least 19 recordsLinked to original sources

PubMed2005

Determination of thiamine and its phosphorylated forms in human plasma, erythrocytes and urine by HPLC and fluorescence detection: a preliminary study on cancer patients.

In man, neurotoxicity associated to ifosfamide treatment can be reversed by intravenous thiamine administration. Trying to explain this clinical finding, we decided to study possible changes in thiamine availability and activation in patients exposed to ifosfamide. Free thiamine and its phosphate esters levels were measured in plasma, erythrocytes and urine by an ion-pair HPLC method with pre-column derivatization, which allowed separation of the fluorescent compounds in less than 10 min. The method was validated by linearity, sensitivity and reproducibility studies, whose values met the demands for bioanalytical assays. This method was applied to assess thiamine status in cancer patients exposed to ifosfamide therapy for advanced disease.

Chromatography, High Pressure Liquid↗

PubMed2004

Determination and in-process control of zolpidem synthesis by high-performance liquid chromatography.

A high-performance liquid chromatographic assay with diode-array detection has been developed for the in-process control of zolpidem synthesis and for the analysis of the drug and its synthetic intermediates. The separation uses a 4.6mm i.d. reversed-phase Kromasil C(18) (150 mm) column, 5 microm particle size with a gradient elution mode of acetonitrile and 0.02 M NH(4)OAc (adjusted to pH 8.0) as the mobile phase (flow rate 1.0 mlmin(-1)). The analysis is performed in 12 min. The method is simple, rapid and highly specific.

Chromatography, High Pressure Liquid↗

PubMed2004

[Surgical treatment of a pheocromocytoma bilateral in a 5 year old patient with the von Hippel-Lindau disease].

INTRODUCTION: The disease of Von Hippel Lindau (VHL) is hereditary and causes a predisposition to the development of tumours. Organs such as the cerebellum, the pancreas, the kidney, the suprarenal glands and the retina are more usually affected by this disease. CLINICAL CASE: We present the case of a 5-year-old patient who suffers from asiymptomatic high blood pressure. In the family antecedents, it is relevant the case of the father, with pheocromocytoma bilateral, which led us to carry out a genetic study of his two sons. Our patient, the younger; presented a mutation of the VHL gene in the short arm of the chromosome 3. In one of the periodic controls, it could be detected high blood pressure of 160/100 mm. Hg, clinically asymptomatic. The other child did not present a genetic mutation and has no disease. The presence of high catecholamines, the detection of a 3 cm left suprarenal mass through the ecography, the TAC that did not show a right suprarenal pathology and the MBIG scintigraphy confirmed the diagnostic of pheocromocytoma. The RNM showed another 0.8-cm mass which confirmed a pheocromocytoma bilateral. We started the treatment against high blood pressure with fenoxibenzamine and diltiazem, and we controlled this problem. We also prepared the pre-and-post operation anesthetic strategy, which is so important for the surgical success. The operation started by a laparoscopic, we made left adrenalectomy and we had to reconvert to laparotomy to make partial right adrenalectomy. Six months after the operation, the patient is free from symptomatology and follows a treatment with glucocorticoides with smaller and smaller doses. COMMENTS: The case is exceptional because it embodies the following characteristics: early diagnostic age, family affectation and discovery of asymptomatic high blood pressure. It needed an appropriate preanesthetic and anesthetic preparation, which gave way to an operation without complications. The postoperation was also stable and presented no complications.

Adrenal Gland Neoplasms↗

PubMed2003

In-process control of midazolam synthesis by HPLC.

A high-performance liquid chromatographic assay coupled with UV detection (239 nm) has been developed for the determination of midazolam and its synthesis precursors. The separation of the analytes was performed on a Kromasil C8 column (15 cm x 4.6 mm i.d., 5 microm) at 30 degrees C. The mobile phase [ammonium chloride (pH 5.5, 1 g l(-1))-methanolacetonitrile (45:22:33, v/v/v)] was pumped at a flow-rate of 1.5 ml min(-1). This method is rapid (less than 11 min), sensitive (limit of detection (LOD) ranged between 0.05 and 0.5 mg l(-1)) and selective for the determination of midazolam, and it could be used for monitoring different synthetic routes.

Chromatography, High Pressure Liquid↗

PubMed2003

HPLC for in-process control in the production of sultamicillin.

A high-performance liquid chromatographic assay coupled with UV detection (215 nm) was developed for the determination of sultamicillin and its synthesis precursors. The separation of the analytes was performed on a Kromasil C(18) column (15 cm x 4.6 mm i.d., 5 microm) at 20 degrees C. The mobile phase (25 mM phosphate buffer, pH 7.0 and acetonitrile 48%) was pumped at a flow rate of 1.0 ml min(-1). This method is sensitive (limits of detection ranged between 0.4 and 1.2 mg l(-1)) and selective for the determination of sultamicillin and could be used for monitoring different synthetic routes.

Ampicillin↗

PubMed2002

In vitro antifungal activity of several antimicrobial compounds against Penicillium expansum.

Fungicides used in the prevention and control of mold rots in stored apples are subjected to legal, social, and biological limitations. The aim of this study was to find an alternative to postharvest fungicides currently used in the prevention and control of blue mold rot caused by Penicillium expansum in apples. For this purpose, the antimicrobial activity and MIC of several substances against P. expansum were evaluated in vitro using different end point methods: agar diffusion assay, volatility method, and agar dilution and broth dilution MIC assays. Most of the substances tested are common food ingredients and have a recognized antimicrobial activity. Essential oils, such as thymol, eugenol, citral and cineole, vanillin, sodium hypochlorite, acetic acid, potassium sorbate, and hydrogen peroxide, were the substances evaluated. Thymol and citral were the essential oil components that showed the greatest inhibitory effects. The effectiveness of 5 and 10% hydrogen peroxide in growth inhibition of P. expansum in the agar diffusion assay was total, and its MIC as determined by the agar and broth dilution assays was less than 0.025%. These results indicate that the application of small quantities of hydrogen peroxide to the apple skin might be an alternative to fungicides in the elimination of P. expansum.

Colony Count, Microbial↗

PubMed2001

(Z)-3-p-tolylsulfinylacrylonitriles as chiral dipolarophiles: reactions with diazoalkanes.

[reaction: see text] The dipolarophilic reactivity of enantiopure (Z)-3-p-tolylsulfinylacrylonitriles (1) has been evaluated with diazoalkanes. 3-Cyanopyrazoles are obtained when R = H, but with R = alkyl (Bn, n-Bu, and t-Bu) only one cycloadduct (4 or 5) is formed in high yield under mild conditions, therefore evidencing a complete control of the regioselectivity and the endo/exo and pi-facial selectivities. These reactions are a new straightforward entry to the synthesis of pyrazolines and related structures and reveal the excellent dipolarophilic features of (Z)-sulfinylacrylonitriles.

Journal Article↗

PubMed2001

Hyperplasia of alveolar neuroendocrine cells in rat lung carcinogenesis by silica with selective expression of proadrenomedullin-derived peptides and amidating enzymes.

Pulmonary neuroendocrine (NE) cells are found as clusters called neuroepithelial bodies (NEBs) or as single cells scattered in the respiratory epithelium. They express a variety of bioactive peptides, and they are thought to be the origin of NE lung tumors. Proadrenomedullin N-terminal 20 peptide (PAMP) is a peptide derived from the same precursor as adrenomedullin (AM). AM and PAMP are C-terminally amidated during their processing by a well-characterized amidating enzyme, peptidylglycine alpha-amidating monooxygenase (PAM). We explored AM, PAMP, and PAM expression as markers for NE hyperplasia in three rodent species (Fischer 344 rats, Syrian golden hamsters, and A/J mice) after a single intratracheal instillation of crystalline silica (quartz), which was previously found to induce different reactions in the three species. Rats developed a marked silicosis, with alveolar and bronchiolar hyperplasia and formation of peripheral lung epithelial tumors. Mice developed a moderate degree of silicosis, but not epithelial hyperplasia or tumors. Hamsters showed dust-storage lesions, but not silicosis or tumors. NE cells were immunolabeled for calcitonin gene-related peptide (CGRP), AM, PAMP, and PAM in serial sections of each lung. The numbers of positive NEBs per lung area and positive cells per NEB were quantified. A marked hyperplastic reaction in the NEBs of silica treated rats occurred only in alveolar NEBs, but not in bronchiolar NEBs. From Month 11 onwards, there were marked differences in the number of alveolar NEBs per section and in the number of cells per alveolar NEB immunoreactive for CGRP. No hyperplastic NE cell reaction was observed in silica-treated mice and hamsters. Significant PAMP and PAM expression was seen only in rat hyperplastic alveolar and in bronchiolar NEBs from Month 11 onwards. In E18, rat fetal lung NEBs were found to be strongly positive for PAMP and PAM.

Adrenomedullin↗

PubMed2000

Simultaneous determination of fat-soluble vitamins and provitamins in dairy products by liquid chromatography with a narrow-bore column.

A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of vitamins A, D2, D3, E and K1, retinyl acetate, retinyl palmitate, tocopherol acetate, ergosterol and 7-dehydrocholesterol in milk and butter. Narrow-bore columns are recommended because this alternative provides a good separation and efficiency, plus greater economy and sensitivity. Detection limits for individual vitamins range from 0.14 to 6.9 ng. All vitamins are separated in less than 33 min. For the simultaneous determination of these vitamins and provitamins we use two sample pre-treatment methods, a liquid-liquid extraction with hexane or a solid-phase extraction with a C18 cartridge. Recovery studies show good results for all solutes (84-108% and 85-108% for milk and butter, respectively) and the intra-day coefficients of variations range from 1.6 to 4.5%. These methods permit the simple determination of fat-soluble vitamins using a small sample volume.

Animals↗

PubMed1999

[Evaluation of a fast urease test for the detection of Helicobacter pylori].

Helicobacter Pylori colonize the gastric mucosa and their adaptation to this environment is related with its high activity urease. This enzyme hydrolyzes the gastric urea, neutralizing the acid environment of the bacteria. Based on that reaction numerous presumptive diagnosis tests, have been developed using a solution of urea (usually 6%) with a pH indicator (usually 0.05% fenol-red); nevertheless, the color changes are so light that some persons do not detect it. For that reason, a modification of that reaction was proposed using a mix of pH indicators (0.05% fenolred and 0.002 bromothymol blue) which induces a color change from light green to deep purple. Also, the reaction of urease was evaluated using only bromothymol blue. The reaction using fenol red as indicator showed the higher values for sensitivity of 58.8% and the specificity of 66.6%; whereas using only bromothymol-blue those values were 46 y 71.4% respectively. The efficiency of the test using fenol-red or the mix of this bromothymol- was 64.2 y 62.2%, respectively; however, the mix of indicators induce a change color easily detected, because of changes from ligh-green to deep-purple.

Bromthymol Blue↗

PubMed1999

[Extracorporeal respiratory assistance (ECRA): initial experiences in Spain].

UNLABELLED: The attendance respiratory extracorporeal (AREC) is an oxygenation form for membrane extracorporeal with flow tidal and veno-venous cannula described by Chevalier et al. in 1990. We present our clinical experience so much with AREC in system veno-venous flow tidal as veno-arterial. From october of 1997 until the present time we have treated three patients by means AREC, in two patients with veno-venous system and in one veno-arterial. In all the cases bomb Collin-Cardio has been used with bladder for flow tidal and membrane of oxygenation of 0.8 m2, being inserted a system of alternative clamp of the branches of the circuit. The system AREC has been used in two patients with congenial diaphragmatic hernia, right in a case and left in the other one. The gestational age was of 38 and 36 weeks with a weight of 3,200 and 2,900 grams. Both patients were remitted from other centers by failure of the conventional treatment. In both cases the indication of AREC was the sharp deterioration of the general state with failure of the conservative treatment, being the previous oxygenation index of 109 and 112. The third patient precised veno-arterial AREC for ventricular failure during the correction of the congenital heart disease, this patient was 5 month old and the weight was 5,000 grams. The duration of AREC in the cases of congenital diaphragmatic hernia was of 14 and 10 days. In a patient the diaphragmatic hernia was corrected at the 55 hours of being in AREC. In the second case the hernia had been surgical corrected in another center. The exit of AREC in both cases carries out after a discreet improvement of the lung function. Both patients died at the 24 and 48 hours of the decannulation for cerebral hemorrhage and respiratory failure. The third patient stayed stable in veno-arterial AREC during 4 days, with hemodynamic support of 130 ml/kg/min, retiring the support to present absence of cerebral activity. CONCLUSIONS: With the derived limitations of the extreme severity of the treated cases and the current phase of beginning of the AREC team, we think that it is a useful and available technique in our country, for the handling of patient with cardiorespiratory failure while waiting for improvement of their base pathology.

Age Factors↗

PubMed1998

Formulation of L-asparaginase-loaded poly(lactide-co-glycolide) nanoparticles: influence of polymer properties on enzyme loading, activity and in vitro release.

This paper describes the preparation and characterisation of poly(lactide-co-glycolide) (PLG) nanoparticles containing the enzyme L-asparaginase. L-Asparaginase was encapsulated in PLG nanospheres using a water-in-oil-in-water solvent evaporation technique. The effect of the copolymer molecular weight and the presence of carboxyl-end groups in the copolymer chain on the physicochemical and in vitro release properties of the nanoparticles was investigated. Results indicated that size, encapsulation efficiency and in vitro release properties (enzymatic activity retention and protein quantification) of the nanoparticles were affected by the PLG molecular weight. As expected, nanoparticles made of high-molecular-weight PLG had a larger size, a higher loading and la slower release rate than those made od a low-molecular-weight PLG. Nevertheless, the most relevant factor affecting the entrapment and release of L-asparaginase from PLG nanoparticles was the presence of free carboxyl-end groups in the PLG chain. The nanoparticles made of PLG with free carboxyl-end groups had a high protein loading (4.86%, w/w) and provided a continuous delivery of the active enzyme for 20 days. However, the enzyme loading was lower (2.65%, w/v) and no active enzyme was detected in the release medium after a 14-day incubation period when nanoparticles were made of PLG with carboxyl-end groups esterified. These results give evidence of the potential of PLG nanospheres for the continuous delivery of L-asparaginase for extended periods of time and show the effect of the PLG chain end-groups in the amount and activity of the enzyme loaded into the nanospheres.

Asparaginase↗

PubMed1998

Protein encapsulation and release from poly(lactide-co-glycolide) microspheres: effect of the protein and polymer properties and of the co-encapsulation of surfactants.

Despite the recognised role of the poly(lactide-co-glycolide) (PLGA) in the encapsulation and release of proteins from PLGA microspheres, the importance that the characteristics of the protein have in these processes has not yet been sufficiently investigated. The aim of this work was to study the simultaneous effect of the protein and PLGA properties and of the microencapsulation process on the physicochemical and in vitro release characteristics of protein-loaded PLGA microspheres. Two model proteins of different isoelectric points (pI), bovine serum albumin (BSA) (pI = 4.6) and lysozyme (LZM) (pI = 11.2), and two different molecular weights (Mw) of PLGA were selected. Microspheres were prepared using the water-in-oil-in-water (w/o/w) solvent extraction and the oil-in-oil (o/o) solvent evaporation techniques. Results showed that BSA was efficiently encapsulated independent of the PLGA Mw, whereas the encapsulation of LZM was favoured with the low Mw PLGA. The co-encapsulation of a surfactant (poloxamer 188 or 331) reduced the protein encapsulation efficiency, especially of BSA. These results suggested that the tensoactive properties of the protein and its affinity for the PLGA are major determinants of the protein encapsulation. Both proteins released faster from the microspheres prepared by the o/o solvent evaporation procedure, with respect to those prepared by the w/o/w solvent extraction technique. In addition, both polymer Mw and protein type had an effect on the protein release rate. The release rate of both proteins, in the absence of a surfactant, was faster from the low Mw PLGA microspheres. However, the release rate constant was higher for BSA than for LZM irrespective of the PLGA Mw. In addition, the co-encapsulation of a surfactant led, in most cases, to a faster release of the encapsulated protein. To conclude, these results suggest that protein release from PLGA microspheres is not only governed by the PLGA erosion rate and protein diffusion through the water-filled channels, but is highly affected by the protein properties and its possible interaction with PLGA and its degradation products.

Chemical Phenomena↗

PubMed1998

[Secondary effects of prostaglandin E1 on the management of hypoplastic left heart syndrome while waiting for heart transplantation].

OBJECTIVE: Newborns with hypoplastic left heart syndrome (HLHS) included in the heart transplant program depend on continuous prostaglandin E1 (PGE1) perfusion for a prolonged period of time, which can result in various side effects. The objective of this study was to analyze the side effects derived from the use of PGE1 in newborns with HLHS who are awaiting heart transplantation. PATIENTS AND METHODS: Fifteen newborns with HLHS included in a cardiac transplant program between January 1993 and August 1996 were studied. All received continuous endovenous perfusion of PGE1 from the time of diagnosis of the cardiopathy. RESULTS: Thirteen patients were transplanted, with 6 dying in the operating room. Seven survived. Two patients died while waiting for a transplant. All presented short term side effects derived from the continuous perfusion of PGE1, including a slight fever and irritability. However, none of them presented apnea pauses. Cortical hyperostosis and anthral hyperplasia were observed in 13 (83.3%) and 12 (80%) cases, respectively, but in all transplanted cases regression of the anthral hyperplasia was seen after 6 months and regression of the cortical hyperostosis was seen after 12 months. CONCLUSIONS: PGE1 was effective in maintaining the permeability of the ductus arteriosus. The side effects derived from the treatment were well tolerated. The appearance of cortical hyperostosis and anthral hyperplasia is related to the duration of the perfusion and these disappear in the weeks following the suspension of PGE1 treatment.

Alprostadil↗

PubMed1997

Effect of magnesium sulfate administration on subendocardial and subepicardial perfusion.

The objective of this study was to determine the effect of systemic MgSO4 infusion on subendocardial and subepicardial perfusion. Seventeen spontaneously breathing piglets were examined. Myocardial perfusion was measured using radiolabeled microspheres at baseline, 30 and 60 min after either MgSO4 (80 mg/kg) or saline infusion. Blood pressure, heart rate, and cardiac output were also measured at these time intervals. Comparison of the magnesium-induced changes in systemic blood pressure and on subendocardial and subepicardial perfusion at 30 and 60 min with values obtained with saline solution at 30 and 60 min, yielded no statistically significant difference (Tables 1-3). The ratio of subendocardial/subepicardial blood flow and subendocardial and subepicardial coronary vascular resistance at 30 and 60 min revealed no statistically significant differences between the magnesium and the control group (Table 3). There were no statistically significant difference in cardiac output and heart rate during any of the measured periods (Table 2). Our results suggest that the administration of MgSO4 does not alter the ratio of subendocardial/subepicardial blood flow and the ratio of subendocardial/subepicardial coronary vascular resistance.

Animals↗

PubMed1997

Potential virulence determinants of Salmonella serovars from poultry and human sources in Spain.

A total of 173 Salmonella strains of different serovars isolated during 1992 from poultry and human sources in Zaragoza (NE Spain) were investigated for potential virulence factors. Parameters studied included production of aerobactin, enterobactin, colicin (including colicin V) and hemolysin, serum resistance against serum from man, sheep, cattle and chicken, binding of Congo red and crystal violet, auto-agglutination and calcium dependency at 37 degrees C and double colony morphology. Preliminary studies showed tests with completely negative results (colicins and hemolysin production, double colony morphology, auto-agglutination and calcium dependency at 37 degrees C) and tests with completely positive results (enterobactin production and binding of Congo red). The tests with variability of results were production of aerobactin, serum resistance and crystal violet binding. Aerobactin production was detected in 80% of Salmonella strains of clinical human origin and in 30% of Salmonella strains isolated from healthy slaughtered chickens. Sixty-five per cent of patient isolates were human serum resistant, 73% were ovine serum resistant, 85% were bovine serum resistant and 98% were chicken serum resistant. The percentages of poultry isolates serum resistant were 61, 86, 60 and 89% in human, ovine, bovine and chicken serum, respectively. Crystal violet binding was detected in 22.5% of Salmonella isolates from human origin and in 32.3% of Salmonella strains from poultry origin. This study can form a marker for the prevalence of strains with various characteristics (production of aerobactin, serum resistance and crystal violet binding) for comparison in future epidemiological studies. Furthermore, the data of this work suggested that strains causing enteric salmonellosis in man are partially identical to strains isolated from carrier broilers.

Abattoirs↗

PubMed1997

[Presence of Listeria monocytogenes and Listeria sp. in fresh and cured sausages. Use of different conditions of time and temperature for incubation].

Two different temperatures for enrichment of Listeria monocytogenes and related species have been studied (1) cold enrichment at 4 degrees C (2) enrichment at 30 degrees C (FDA method). Also, two selective media for isolation were tested: Acriflavine-Ceftazidime agar (A.C.) and Palcam agar. We have studied 72 samples of dry-cured sausage (called 'longaniza') at different stages of maturation: fresh, semi-cured and cured samples. The most efficient method was cold enrichment at 4 degrees C during 5 days followed by isolation in Palcam agar, but results were only significant for fresh sausages (P < 0.05).

Animals↗

PubMed1996

Thoracic epidural anesthesia via the lumbar approach in infants and children.

BACKGROUND: In upper abdominal or chest surgery, the segmental approach to thoracic epidural space has the advantage of reducing the total dose of local anesthetic needed. This approach, however, is associated with greater risk of neurologic damage or dural puncture. The aim of this study was to assess the success and the degree of difficulty in advancing a 19-G catheter from the lumbar epidural space to the thoracic level in patients aged 0-96 months. METHODS: In 39 patients undergoing abdominal surgery, the cutaneous distance between the L4-L5 and T10-T11 interspaces was measured, and an appropriate length of 19-G catheter was inserted into the epidural space through an 18-G Tuohy needle with bevel directed cephalad. The intent was to advance the full length of catheter measured to reach the objective. The tips were observed radiologically, and all those positioned cephalad to the T12 level were considered well placed. The degree of difficulty in advancing the catheter was classified as easy, difficult, or impossible. Complications reported were vascular and/or spinal puncture and difficulty removing the catheter. RESULTS: The catheter tip reached T10-T12 in 7 patients, L2 in 1, L3 in 8, and L4-L5 in 23. Forty-eight percent of the catheters described as easily advanced remained at the L4-L5 level, and only 22% reached the desired level. Difficult insertions occurred in eight patients, in whom the objective was never reached. One case of intravascular insertion was reported. All catheters were removed without difficulty. CONCLUSIONS: The 19-G catheter is inappropriate for use in reaching the thoracic epidural space by the lumbar approach. Easy entrance of a catheter is not a reliable sign of having reached the desired level.

Anesthesia, Epidural↗