PubMed Health⌕ Search

Biomedical subjects

T Martínez

Publications and source records attributed to T Martínez.

At least 19 recordsLinked to original sources
PubMed2006

Observation of 54Ni: cross-conjugate symmetry in f7/2 mirror energy differences.

Gamma decays from excited states up to Jpi=6+ in the N=Z-2 nucleus 54Ni have been identified for the first time. Level energies are compared with those of the isobars 54Co and 54Fe and of the cross-conjugate nuclei of mass A=42. The good but puzzling f7/ cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.

Journal Article↗
PubMed2006

Aplidin induces JNK-dependent apoptosis in human breast cancer cells via alteration of glutathione homeostasis, Rac1 GTPase activation, and MKP-1 phosphatase downregulation.

Aplidin is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulation of Rac1 by transfection of small interfering RNA (siRNA) duplexes or the use of a specific Rac1 inhibitor decreased Aplidin-induced JNK activation and cytotoxicity. Our results show that Aplidin induces apoptosis by increasing the GSSG/GSH ratio, a necessary step for induction of oxidative stress and sustained JNK activation through Rac1 activation and MKP-1 downregulation.

Animals↗
PubMed2006

[Hemodialysis prospective multicentric quality study].

In medicine a considerable amount of resources are used in research, but very little attention is paid to ensuring that the findings of research are implemented in routine clinical practice. This prospective study has the aim to evaluate the efficiency of some clinical management strategies (feedback, benchmarking and improving plans) on haemodialysis treatment results in 4 different dialysis centres. We collected consensus data related to haemodialysis results every 6-8 months and informed each centre about its own results (feedback) and how these related to the others(benchmarking). We designed improving plans for any bad result detected. By the end of two years of follow up, 294 patients had been included in the study. The results obtained at the end of the study had improved in comparison with those obtained at the beginning (statistically significant) for the following indicators: % of patients with Hb< 11 g/dl, % patients with Kt/v < 1.2, mean Kt/v, mean albumin, % patients with albumin< 3.5 g/dl y % patients with C reactive protein (CRP) > 5 mg/dl. No statistical changes were found in: mean erythropoietin (EPO) doses, blood pressure (BP), phosphorus plasmatic,calcium-phosphorus product, parathormone (PTHi) and vascular access distribution. We explained the absence of any improvement because of adequate start indicators in some areas (BP and vascular access), therapy with limited efficiency (calcitriol, calcium carbonate and others), lack of support resources (dietetic unit) or inadequate design/implementation of improving plans.In conclusion, our intervention illustrates that combined clinical management strategies(feedback, benchmarking and improving plans) are efficiency in improving some areas of haemodialysis treatment (anaemia, dialysis dose, nutrition and inflammation), although it does not improve calcium phosphate metabolism related indicators.

Aged↗
PubMed2005

The behavior of single crystals of NaCl: Ca2+, Mn2+ exposed to gamma rays.

The behavior of single crystals of NaCl: Ca(2+), Mn(2+) exposed to gamma rays was explored for its potential usage as a dosimeter. The study was focused to the effect of dose and dose rate. The crystals were analyzed using thermoluminescence (TL). The productions of irradiation defects in the solid were correlated with the glow curve. F-centers were measured as function of the dose. The bleaching of the F-centers produced a decrease of the peak of the glow curve. The results showed that the response is linear in an interval up to 60 Gy.

Calcium↗
PubMed2005

Iron salts in solid state and in frozen solutions as dosimeters for low irradiation temperatures.

The aim of this work is to study the irradiation of iron salts in solid state (heptahydrated ferrous sulfate) and in frozen acid solutions. The study is focused on finding their possible use as dosimeters for low temperature irradiations and high doses. The analysis of the samples was made by UV-visible and Mössbauer spectroscopies. The output signal was linear from 0 to 10 MGy for the solid samples, and 0-600 Gy for the frozen solutions. The obtained data is reproducible and easy to handle. For these reasons, heptahydrate iron sulfate is a suitable dosimeter for low temperature and high irradiation doses, in solid state, and in frozen solution.

Cold Temperature↗
PubMed2003

Assessment of exhaled nitric oxide kinetics in healthy infants.

Exhaled nitric oxide (Fe(NO)) measurements provide a noninvasive approach to the evaluation of airway inflammation. Flow-independent NO exchange parameters [airway NO transfer factor (D(NO)) and airway wall NO concentration (Cw(NO))] can be estimated from Fe(NO) measurements at low flows and may elucidate mechanisms of disturbances in NO exchange. We measured Fe(NO) in sedated infants by using an adaptation of a raised lung volume rapid thoracic compression technique that creates forced expiration through a mass-flow controller that lasts 5-10 s, at a constant preset flow. We measured Fe(NO) at expired flows of 50, 25, and 15 ml/s in five healthy infants (7-31 mo). Median Fe(NO) increased [24, 40, and 60 parts per billion (ppb)] with decreasing expiratory flows (50, 25, and 15 ml/s). Group median (range) for D(NO) and Cw(NO) were 12.7 (3.2-37) x 10(-3) nl. s(-1). ppb(-1) and 108.9 (49-385) ppb, respectively, similar to values reported in healthy adults. Exhaled NO is flow dependent; flow-independent parameters of exhaled NO kinetics can be assessed in infants and are similar to values described in adults.

Breath Tests↗
PubMed2001

[Transdermal nitroglycerin versus corticosteroid infiltration for rotator cuff tendinitis].

AIMS: To compare transdermal nitroglycerin (NTG) and corticosteroid infiltration in patients with rotator cuff tendinitis (RCT). DESIGN: Experimental, randomized controlled study. SETTING: Semirural basic health area in the Garraf region of Barcelona province, Spain, with a population of public health service users of 12000. PATIENTS AND METHODS: Patients diagnosed as having RCT of less than 6 weeks' evolution who had not responded to treatment with oral nonsteroid antiinflammatory drugs. The patients were distributed randomly into two groups: a) group A, local infiltration via a posterior approach with a depot corticosteroid and local anesthesia, and b) group B, treated for 3 days with a 5-mg NTC patch. MAIN MEASURES: Age, sex, pain (measured with an analog visual scale) and adverse events. In patients who showed a partial response, treatment was repeated up to 3 times at 15-day intervals. Pain was tested after 7-10 days of treatment. Complete improvement was considered a reduction in pain of more than 5 points on the analog visual scale; partial improvement was considered a reduction of 3-5 points, and treatment failure was recorded when there was no improvement in pain or when there was a decrease of less than 3 points. RESULTS: A total of 48 patients were included; 33 (69%) were women and 15 (31%) were men. Mean age was 61 years. In group A, complete improvement was seen in 19 patients and partial improvement in 3; treatment failed in 2 patients. In group B complete improvement was seen in 5 patients, partial improvement in 5, and failure of treatment in 14. The difference between groups was statistically significant. Adverse events were mild pain at the injection site in 4 patients from group A, and headache in 15 patients from group B, 8 of whom abandoned treatment for this reason. CONCLUSION: Treatment with NTG is not a clear alternative to infiltration of corticosteroids in patients with RCT, because of its lack of effectiveness and because of the greater number of patients who had adverse events that lead them to abandon treatment.

Analgesics↗
PubMed2001

Coulomb energy differences in t = 1 mirror rotational bands in (50)Fe and (50)Cr.

Gamma rays from the N = Z-2 nucleus (50)Fe have been observed, establishing the rotational ground state band up to the state J(pi) = 11+ at 6.994 MeV excitation energy. The experimental Coulomb energy differences, obtained by comparison with the isobaric analog states in its mirror (50)Cr, confirm the qualitative interpretation of the backbending patterns in terms of successive alignments of proton and neutron pairs. A quantitative agreement with experiment has been achieved by exact shell model calculations, incorporating the differences in radii along the yrast bands, and properly renormalizing the Coulomb matrix elements in the pf model space.

Journal Article↗
PubMed2001

Management of cancer of the supraglottis.

We present the results of a retrospective study of 903 patients treated with conservation surgery for carcinoma of the supraglottic larynx so we can evaluate our management of supraglottic cancer with different types of surgery. In 301 patients, an extended supraglottic laryngectomy was performed. The recent selective use of transoral laser resection appears to be a rational approach. The 5-year uncorrected survival was 84%, 81%, 76%, and 55% for stages I, II, III, and IV, respectively. The most common site for local-regional failure was the cervical lymphatics. The percentage of occult disease in the NO neck was 21% and epilaryngeal supraglottic location, locally advanced and GIII tumors have a higher frequency of lymph node involvement. There were no differences between comprehensive and anterolateral elective neck dissections. A bilateral elective neck dissection is recommended. In histologically positive neck disease, the survival rates were better with postoperative radiotherapy only in cases of extracapsular spread.

Carcinoma↗
PubMed2001

Urinary selenium excretion in patients with cervical uterine cancer.

In this work, we report on a relationship between urinary selenium and the development of cervical uterine cancer. A simple chemical method was developed to concentrate trace amounts of selenium from relatively large urine samples by use of small activated carbon filters. When these filters are irradiated with thermal neutrons, selenium can be determined either by 77mSe (t1/2 = 17.5 s) or 75Se (t1/2 = 120 d). In this article, we report the results for 82 urine samples from women with cervical uterine cancer in several stages of development and from healthy controls. These results show a statistically significant increase of selenium excretion in cancer patients as compared to controls. Urinary selenium excretion is highest for patients in the intermediate stages of the disease.

Adult↗
PubMed2000

Sequence and evolution of a hexamerin from the ant Camponotus festinatus.

In the ant Camponotus festinatus, two different hexamerins accumulate stage-specifically during the late larval period and at various times in adults. These hexamerins serve as storage proteins and play important roles in brood nourishment and colony founding. We report an analysis of the cDNA sequence of C. festinatus hexamerin 2 (CfeHex2). The native protein contains 732 amino acids, which are moderately enriched in aromatic amino acids, aspartate and asparagine. Phylogenetic analyses show a close relationship of CfeHex2 to a putative toxin of the braconid wasp, Bracon hebetor. The divergence of Formicidae and Braconidae hexamerins was calculated to have begun 187 MYA, an estimate consistent with currently accepted phylogeny of insect orders.

Amino Acid Sequence↗
PubMed1995

Storage proteins in ants (Hymenoptera:Formicidae).

Storage proteins are a major feature of holometabolous development in insects, accumulating during the larval period and disappearing during metamorphosis. In ants (Hymenoptera:Formicidae), storage proteins also play important roles in adult females. Three types of storage proteins have been characterized from ants: hexamerins, proteins high in glutamine/glutamic acid, and very high density lipoproteins (VHDLs). The hexamerins have moderately high levels of aromatic amino acids and belong to the arthropod hemocyanin family of proteins. The proteins high in glutamine/glutamic acid can form hexamers under some conditions, but the subunit size is larger than that of typical hexamerins. The VHDLs are dimeric and share features with storage chromoproteins described from Lepidoptera. In Camponotus festinatus (Formicinae), storage proteins are found in adult ants in two situations. First, lack of brood stimulates workers to accumulate the same two storage hexamers found in larvae. Second, young virgin queens store large reserves of these proteins before mating. Protein storage by queens has been confirmed in two other subfamilies of ants, indicating it is widespread. The capacity to store proteins as adults enables queens to rear brood without leaving the nest and workers to store rich reserves and regulate larval diet seasonally.

Animals↗
PubMed1995

Somatosensory evoked potential elicited by acupoint's stimulus.

Based on the observation that repeated acupoint stimulation elicits evoked potentials whose latency varies as a result of the stimulus intensity we assessed the evoked potential elicited by stimulus of three acupoints (Hegu, Shenmen and Houxi), comparing the results to the potentials produced by median nerve stimulus and nonacupunctural point. Fourteen healthy individuals were studied, and no modifications related to the Hegu and Shenmen point potentials increased with the amount of stimuli, until it reached a plateau at around 400 stimuli. It did not vary for Houxi and the nonacupunctural point. We conclude that the somesthesic afference from acupunctural points must involve control circuits that are quantitatively different for each point.

Acupuncture Points↗