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Biomedical subjects

E M González

Publications and source records attributed to E M González.

14 recordsLinked to original sources
PubMed2004

A new area multidetector dosemeter for mixed n-gamma fields.

A new instrument to assess neutron ambient doses has been designed and constructed. In its design, spectrometric capabilities have been implemented that allow to take into account the energy spectrum of the neutron field in the evaluation of the operational magnitude, ambient dose equivalent, H*(10). This dosemeter is based on the moderation-absorption technique and can be employed over a wide range of energies from thermal to 20 MeV. It consists of a spherical shaped polyethylene moderator with a set of thermoluminescence dosemeters (TLDs) inserted in different positions of its interior to evaluate the external neutron energy spectrum. At this moment the system uses pairs 6LiF:Mg,Ti (TLD-600) and 7LiF:Mg,Ti (TLD-700) thermoluminescence dosemeters for a better gamma discrimination. The dosemeter response matrix was calculated using the MCNP4C Monte Carlo code (MC). The viability of the dosemeter for area dosemetry has been examined experimentally showing its capabilities over a wide range of energies.

Algorithms↗
PubMed2002

Allergenic diversity of the olive pollen.

A great number of allergenic proteins have been detected in olive pollen extracts. To date, nine allergens have been isolated and characterized, which have been called Ole e 1 to Ole e 9. The most prevalent olive allergen is Ole e 1, which affects more than 70% of patients hypersensitive to olive pollen, but others, such as Ole e 2, Ole e 8, and Ole e 9, have been demonstrated to be major allergens, and Ole e 6 or Ole e 7 reach high values of clinical incidence. Many of these allergens, such as Ole e 2 (profilin) and Ole e 3 (polcalcin), are involved in cross-reactivities, which agrees with their adscription to panallergenic families. Among the many olive allergens of high molecular mass, only Ole e 9 (46 kDa) has been characterized. The allergen is a polymorphic and glycosylated beta-1,3-glucanase, which belongs to a pathogenesis-related (PR-2) protein family. In addition to the polypeptide epitopes, Ole e 1 also exhibits IgE-binding determinants in the carbohydrate, which are recognized by more than 60% of the sera from patients sensitive to the whole allergen, although the level of such glycan-specific IgE seems not to be clinically relevant in the overall content of the sera. Recent advances in the elucidation of the structure of the Ole e 1-oligosaccharide component allows us to explain the antigenicity of the molecule. Finally, the recombinant production of several allergens from olive pollen in both bacterial and eukaryotic cells has allowed us to resolve problems derived from the polymorphism and scarcity of the natural forms of these allergens. The biological equivalence between the natural and recombinant forms lets us initiate studies on the design of mixtures for clinical purposes, in which hypoallergenic derivatives of these allergens could play a definitive role.

Allergens↗
PubMed2001

Long-term biliary complications after liver surgery leading to liver transplantation.

Chronic biliary obstruction with repeated bouts of cholangitis adversely affects quality of life and may lead to secondary biliary cirrhosis with liver failure. We reviewed our experience with chronic biliary complications after surgical treatment of various diseases that at the end needed a liver transplantation. Twelve patients with previous biliary surgery developed secondary biliary cholangitis, secondary biliary cirrhosis, or both. Seven had surgery for liver hydatid disease by Echinococcus granulosus, another four had complicated biliary surgery unrelated to hydatid disease, and one had a history of a traffic accident with liver trauma and hepatectomy with chronic biliary fistula. The repeated cholangitis attacks and in two cases of hydatid disease the development of biliary-bronchial fistulas made these patients' lives miserable. All had had previous surgical procedures that made the transplantation procedure more difficult. Nevertheless, patient survival and graft actuarial survival after liver replacement were 75.0% and 69.2%, respectively, at 5 years.

Biliary Tract Diseases↗
PubMed2001

Abscisic acid induces a decline in nitrogen fixation that involves leghaemoglobin, but is independent of sucrose synthase activity.

Sucrose synthase (SS) activity has been suggested to be a key point of regulation in nodule metabolism since this enzyme is down-regulated in response to different stresses which lead to decreased nitrogen fixation. In soybean, a dramatic decline of SS transcripts has been observed within 1 d from the onset of drought. Such a quick response suggests mediation by a signal transduction molecule. Abscisic acid (ABA) is a likely candidate to act as such a molecule as it mediates in a significant number of plant responses to environmental constraints. The hypothesis of ABA controlling nodule metabolism was approached in this work by assessing nodule responses to exogenous ABA supply in pea. Under the experimental conditions, ABA did not affect plant biomass, nodule numbers or dry weight. However, nitrogen fixation rate was reduced by 70% within 5 d and by 80% after 9 d leading to a reduced plant organic nitrogen content. Leghaemoglobin (Lb) content declined in parallel with that of nitrogen fixation. SS activity, however, was not affected by ABA treatment, and neither were the activities of the enzymes aspartate amino transferase, alkaline invertase, malate dehydrogenase, glutamate synthase, uridine diphosphoglucose pyrophosphorylase, isocitrate dehydrogenase, and glutamine synthetase. Nodule bacteroid-soluble protein content was reduced in nodules only after 9 d of ABA treatment. These results do not support the hypothesis that ABA directly regulates SS activity. However, they do suggest the occurrence of at least two different control pathways in nodules under environmental constraints, which include ABA being involved in a Lb/oxygen-related control of nitrogen fixation.

Abscisic Acid↗
PubMed2001

Optimising the treatment of upper gastrointestinal fistulae.

A three stage strategy is generally employed in the management of gastrointestinal fistulae which can form due to surgery, disease, or trauma. The condition is investigated leading to diagnosis, conservative treatment is initiated to stabilise the patient, followed by specific surgical treatment measures in complicated cases, or in the absence of spontaneous closure. Conservative management of fistulae is based on parenteral nutrition and bowel rest, as well as on control of infection, electrolytic disturbances, and local care of the fistula tract. Surgical treatment may be required although generally only in particularly serious cases. Somatostatin-14 has been used in addition to parenteral nutrition to further reduce the volume and enzymatic activity of the fluid output through the fistula tract, generally with good results. The majority of reports have shown a beneficial effect, and randomised studies have demonstrated a reduction in closure time and morbidity. However, due to a combination of the seriousness and rarity of the condition and the difficulties inherent in trial design, data from large scale, double blind, randomised, controlled studies investigating the use of pharmacotherapy in the treatment of established gastrointestinal fistulae are lacking. Nevertheless, preliminary data from initial trials suggest that somatostatin-14 and its analogue octreotide considerably improve the conservative treatment of gastrointestinal fistulae in the absence of distal obstruction. In addition, reduction of the concentration of caustic enzymes in the discharge will benefit both wound healing and nutritional losses. With reduced closure time, the period of hospitalisation will be shortened with potentially considerable economic reductions and improvements in quality of life for the patient.

Anti-Bacterial Agents↗
PubMed2000

Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit.

The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage, Autumn Bliss, Rubi, and Zeva) grown in Spain were detected and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degrees C for a one year period. Ellagic acid [207-244 mg kg(-)(1) of fresh weight (fw)], total phenolic (137-1776 mg kg(-)(1) of fw), and vitamin C (221-312 mg kg(-)(1) of fw) contents in raw material were higher in the late cultivars Zeva and Rubi than in the early cultivars Autumn Bliss and Heritage. The freezing process slightly affected the values of extracted ellagic acid, total phenolic, and vitamin C content. At the end of long-term frozen storage (12 months), no significant change of total phenolic content extracted was observed, but significant decreases of 14-21% in ellagic acid and of 33-55% in vitamin C were quantified. Free radical scavenging capacity measured as antiradical efficiency (AE) depends on the seasonal period of harvest. Late cultivars, Rubi (6.1 x 10(-)(4)) and Zeva (10.17 x 10(-)(4)), showed higher AE than early cultivars, Heritage (4.02 x 10(-)(4)) and Autumn Bliss (4.36 x 10(-)(4)). The freezing process produced a decrease of AE values in the four cultivars ranging between 4 and 26%. During the frozen storage, the AE values reached after the freezing process remained unchanged.

Ascorbic Acid↗
PubMed2000

Partial characterization of peroxidase and polyphenol oxidase activities in blackberry fruits.

A partial characterization of peroxidase (POD) and polyphenol oxidase (PPO) activities in blackberry fruits is described. Two cultivars of blackberry (Wild and Thornless) were analyzed for POD and PPO activities. Stable and highly active POD and PPO extracts were obtained using insoluble poly(vinylpyrrolidone) and Triton X-100 in 0.05 M sodium phosphate, pH 7.5, buffer. Blackberry POD and PPO activities have a pH optimum of 6.5, in a reaction mixture of 0.2 M sodium phosphate. Optimal POD activity was found with 3% o-dianisidine. Maximum PPO activity was found with catechol (catecholase activity) followed by 4-methylcatechol. Polyacrylamide gel electrophoresis of blackberry extracts under non-denaturing conditions resolved in various bands. In the POD extracts of Wild fruits, there was only one band with a mobility of 0.12. In the Thornless POD extracts there were three well-resolved bands, with R(f) values of 0.63, 0.36, and 0.09. Both the Wild and Thornless blackberry cultivars produced a single band of PPO, with R(f) values of 0.1 for Wild and 0.06 for Thornless.

Buffers↗
PubMed2000

Allergenic cross-reactivity of olive pollen.

BACKGROUND: Sera of patients allergic to olive (Olea europaea) pollen were used to analyze the IgE cross-reactivity between olive-pollen extract and other pollens obtained from phylogenetically unrelated species. METHODS: We used IgE immunostaining of pollen extracts blotted to nitrocellulose membranes after SDS-PAGE and inhibition analysis of this binding. RESULTS: A high inhibition of the IgE binding on olive-pollen extract was exhibited by birch, mugwort, pine, and cypress pollens, suggesting that these extracts contain proteins which share common epitopes and thus can be recognized by olive-allergic sera. IgE binding to Gramineae pollen extracts was not inhibited by olive-pollen extract, indicating a primary sensitization of the patients to these species. From the inhibition assays, the presence of an allergen of 45 kDa in the olive pollen, which has no homologous counterparts in other allergenic species, has been inferred. CONCLUSIONS: Olive pollen contains allergens which cross-react with pollens from unrelated species, a fact that could simplify the diagnosis and treatment of pollinosis.

Allergens↗
PubMed1999

Partial characterization of polyphenol oxidase activity in raspberry fruits.

A partial characterization of polyphenol oxidase (PPO) activity in raspberry fruits is described. Two early cultivars harvested in May/June (Heritage and Autumm Bliss) and two late cultivars harvested in October-November (Ceva and Rubi) were analyzed for PPO activity. Stable and highly active PPO extracts were obtained using insoluble poly(vinylpyrrolidone) (PVP) and Triton X-100 in sodium phosphate, pH 7.0 buffer. Polyacrylamide gel electrophoresis of raspberry extracts under nondenaturing conditions resolved in one band (R(f)()(1) = 0.25). Raspberry PPO activity has pH optima of 8.0 and 5.5, both with catechol (0.1 M). Maximum activity was with D-catechin (catecholase activity), followed by p-coumaric acid (cresolase activity). Heritage raspberry also showed PPO activity toward 4-methylcatechol. Ceva and Autumm Bliss raspberries showed the higher PPO activity using catechol as substrate.

Catechol Oxidase↗
PubMedDate not supplied

Marginal donors in liver transplantation.

The use of marginal donors has become very common in many liver transplantation units due to the increase in the number of possible recipients. Experience has shown that previous donor protocols were too restrictive. Meanwhile, formerly unknown factors influence current donor evaluation. Different donor factors affecting the outcome of transplantation have been studied. Current absolute contraindications are severe macrosteatosis, long ischemia, sepsis, some viral infections and extra-CNS malignancy. Old age, mild to moderate steatosis, long ICU stay, altered liver function tests, hypernatremia, hypotension and pressors, moderately prolonged ischemia and sex mismatch are usually considered relative contraindications. The result of this wider acceptance policy has been an increasing number of usable livers without deleterious influences on graft and patients survival.

Humans↗