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Biomedical subjects

J Moreno

Publications and source records attributed to J Moreno.

At least 73 records · Page 4Linked to original sources
PubMed2000

Usefulness of unipolar electrograms to detect isthmus block after radiofrequency ablation of typical atrial flutter.

BACKGROUND: RS morphology of the unipolar electrogram is associated with propagation of the wave front through the exploring electrode, whereas positive uniphasic (R) unipolar electrograms are characteristic of the end of activation. METHODS AND RESULTS: Unipolar electrograms were recorded in 45 consecutive patients with atrial flutter who were undergoing radiofrequency ablation (RFA). Bidirectional cavotricuspid isthmus (CTI) block was achieved in 44 patients. The unipolar electrogram obtained before RFA at the low anterolateral right atrium during coronary sinus pacing changed from RS, rS, or QS to R or Rs in all patients after clockwise CTI block was obtained. The morphology of unipolar electrograms recorded close to the coronary sinus during pacing from the low anterolateral right atrium changed from RS or rS to R or Rs in all but 4 patients after counterclockwise CTI block. In the patient in whom CTI block was not achieved, the RS morphology of the unipolar electrogram remained unchanged. In 18 patients, the results of the RFA were assessed with only the unipolar electrogram. The unipolar electrogram correctly predicted 100% and 89% of the cases of clockwise and counterclockwise CTI block, respectively. CONCLUSIONS: The creation of CTI block is associated with an easily detectable loss of negative components and development of an R or Rs pattern of the unipolar electrogram recorded close to the ablation line while pacing at the opposite side of the CTI.

Aged↗
PubMed2000

Chemical and rheological properties of an extracellular polysaccharide produced by the cyanobacterium Anabaena sp. ATCC 33047.

The cyanobacterium (blue-green alga) Anabaena sp. ATCC 33047 produces an exopolysaccharide (EPS) during the stationary growth phase in batch culture. Chemical analysis of EPS revealed a heteropolysaccharidic nature, with xylose, glucose, galactose, and mannose the main neutral sugars found. The infrared (IR) spectrum of EPS showed absorption bands of carboxylate groups. The average molecular mass of the polymer was 1.35 MDa. Aqueous dispersions at EPS concentrations ranging from 0.2% to 0.6% (w/w) showed marked shear-thinning properties (power-law behavior). Linear dynamic viscoelastic properties showed that the elastic component was always higher than the viscous component. Viscous and viscoelastic properties demonstrated the absence of conformational changes within the concentration range studied. Stress-growth experiments revealed that 0.4% and 0.6% (w/w) EPS dispersions showed thixotropic properties. A detailed comparison of the linear dynamic viscoelasticity, transient flow, and decreasing shear rate flow curve properties was made for 0.4% (w/w) dispersions of xanthan gum (XG), Alkemir 110 (AG), and EPS. Viscoelastic spectra demonstrated that the EPS dispersion turned out to be more "fluidlike" than the AG and XG dispersions. The flow indexes indicated that the EPS dispersion was less shear-sensitive than that of XG, showing essentially the same viscosity, that is, >50 s(-1). The fact that viscosities of EPS and AG dispersions were not substantially different within the shear-rate range covered must be emphasized, in relation to EPS potential applications. The rheological behavior of EPS dispersions indicates the formation of an intermediate structure between a random-coil polysaccharide and a weak gel.

Anabaena↗
PubMed2000

Gap-anisotropic model for the narrow-Gap kondo insulators

A theory is presented which accounts for the dynamical generation of a hybridization gap with nodes in the Kondo insulating materials CeNiSn and CeRhSb. We show that Hund's interactions acting on virtual 4f(2) configurations of the cerium ion can act to dynamically select the shape of the cerium ion by generating a Weiss field which couples to the shape of the ion. In low symmetry crystals where the external crystal fields are negligible, this process selects a nodal Kondo semimetal state as the lowest energy configuration.

Journal Article↗
PubMed2000

Carotenoid content of chlorophycean microalgae: factors determining lutein accumulation in Muriellopsis sp. (Chlorophyta).

Fifteen strains of chlorophycean microalgae have been investigated with regard to their carotenoid profile. Lutein, beta-carotene and violaxanthin were present in virtually all of the strains, lutein, in general, being the most abundant carotenoid, whereas canthaxanthin and astaxanthin were found in some strains only. Chlorella fusca SAG 211-8b, Chlorococcum citriforme SAG 62.80, Muriellopsis sp., Neospongiococcum gelatinosum SAG B 64.80 and Chlorella zofingiensis CCAP 211/14 exhibited high lutein levels, the latter strain containing in addition substantial amounts of astaxanthin. Muriellopsis sp. was further characterized, since besides a high lutein content (up to 35 mg l(-1) culture), it had the highest growth rate (up to 0.17-0.23 h(-1)) and maximal standing cell density (up to 8 x 10(10) cells l(-1) culture). These levels of lutein are in the range of those reported for astaxanthin in Haematococcus and for beta-carotene in Dunaliella, microalgae of recognized interest for the production of these carotenoids. Lutein content of Muriellopsis sp. increased during the exponential phase of growth, with the highest value being recorded in the early stationary phase. Maximum levels of lutein in Muriellopsis sp. cultures were recorded at 20-40 mM NaNO3, 2-100 mM NaCl, 460 micromol photon m(-2) s(-1), pH 6.5 and 28 degrees C, conditions which were, in general, also optimal for cell growth. Growth-limiting conditions, such as pH values of 6 or 9 and a temperature of 33 degrees C, were found to stimulate carotenogenesis in Muriellopsis sp. This strain represents a potential source of lutein, a commercially interesting carotenoid of application in aquaculture and poultry farming, as well as in the prevention of cancer and diseases related to retinal degeneration.

Cell Division↗
PubMed2000

Chemical characterization of asturian cider.

Ninety-four samples of Asturian natural cider were analyzed for titratable and volatile acidities, pH, alcoholic, total polyphenol, and acidic polysaccharide contents, nonvolatile acids, polyalcohols, residual sugars, and major volatile compounds. A partial least-squares regression analysis (PLR-1) was performed to correlate the chemical composition and the origin of the raw material, the cider samples being grouped into two categories: an "odd" class, cider made from foreign apples (1995 and 1997), and an "even" class, ciders made from Asturian apples (1996 and 1998). The mathematical model has a multiple linear correlation coefficient of 80%.

Alcohols↗
PubMed2000

Poland's syndrome and recessive X-linked ichthyosis in two brothers.

Poland's syndrome consists of unilateral congenital absence of the pectoralis major muscle with a variable degree of ipsilateral upper limb deformity. The aetiology of Poland's syndrome is unknown, although an inherited tendency to develop a compromised embryonic vascular supply in the affected areas has been suggested. The majority of reported cases are sporadic, and in only a few instances is there a familial incidence. We describe the occurrence of Poland's syndrome in two brothers who also had recessive X-linked ichthyosis. To the best of our knowledge this is the first report of such an association.

Adolescent↗
PubMed2000

Canine leishmaniasis transmission: higher infectivity amongst naturally infected dogs to sand flies is associated with lower proportions of T helper cells.

The dog is the main reservoir of Leishmania infantum, which is a parasite spread among canine hosts by the bite of sand flies. Phlebotomus perniciosus is the sand fly acting as a major vector in the Mediterranean basin. As a consequence, the dog will suffer from leishmaniasis. In this work the infective capacity of infected dogs, established by direct xenodiagnosis, has been investigated in relation to their immunological status by determining the lymphocyte percentages present in peripheral blood mononuclear cells. We found a significant association between the percentages of T helper cells (CD4/TcR alpha beta(+)and CD4/CD45RA(+)) and the infection rates detected in the vector, while significant association was not detected in the case of the T cytotoxic cells (CD8/TcR alpha beta(+)and CD8/CD45RA(+)). The relationship discovered was that the lower the CD4(+)T cell count, the higher the rate of the infection in the vector.

Animals↗
PubMed2000

Ethical theory and principles: do they have any relevance to problems arising in everyday practice?

This review of ethical theories with application to two difficult obstetric cases will allow the practicing obstetrician and gynecologist to use these theories to help resolve difficult ethical dilemmas. In the first case a pregnant human immunodeficiency virus-infected woman refuses to take triple preventive therapy, with potential fetal harm. In the second case a couple with a quintuplet multifetal pregnancy needs assistance to decide about selective termination to effect fetal reduction.

Caregivers↗
PubMed2000

Loss of heterozygosity on the short arm of chromosome 3 in renal cancer.

3% of human cancers are renal cell carcinomas (RCC). The most common chromosome abnormality found in this tumor is loss of heterozygosity (LOH) on the short arm of chromosome 3, which suggests that there must be one or more tumor suppressor genes between 3p14 and 3p21 near the VHL gene which play a relevant role in renal cancer development. DNA from normal and tumor tissue from 40 patients at various stages of RCC was analyzed for LOH at three microsatellites mapped to 3p (3p14.1-14.3; 3p21.2-21.3 and 3p25) by polymerase chain reaction). 42.5% of the tumors studied showed LOH on at least one locus. 30% showed LOH on only one locus; 5% on two loci and 7.5% on the three loci tested. LOH occurred only on nonpapillary tumors (p = 0.03). Interestingly, all the tumors with LOH on 3p21 were >/=25 mm (p = 0.04; relative risk 1.76, confidence interval: 1.3-2.3).

Adult↗
PubMed2000

Telereconstruction from computerized tomography images for the distance teaching of medicine.

A system for making remote two- and three-dimensional reconstructions from computerized tomography images has been developed in order to improve medical teleteaching. It allows the automatic two- and three-dimensional remote visualization of the anatomical structure of interest. As a part of this system, software has been developed which allows many visual operations or transformations on a remote three-dimensional model. It permits the remote workstation and the local workstation to visualize every transformation simultaneously. It allows a doctor to interact virtually and remotely with the anatomical structure. The software enables examination of the anatomical model from all angles, even from inside (including planar and three-dimensional presentations).

Education, Distance↗
PubMed2000

Image processing from computerized tomography images: virtual reconstruction for telediagnosis.

We have developed a system for remote three-dimensional reconstruction, which facilitates telediagnosis. The telereconstruction system is based on a computerized tomography (CT) scanner, a workstation connected to the CT scanner, a PC, which can be geographically far away from the workstation, and a computer program that we have developed. The workstation allows CT images to be stored and image processing to be carried out. The PC permits the user to control the workstation in making a three-dimensional reconstruction and allows the remote user to see that reconstruction. From the PC various graphical operations can be performed on the three-dimensional model, such as rotations, translations and cuts through the model. The program therefore allows a remote user to have three-dimensional images and to study them by means of all the options the program provides.

Image Processing, Computer-Assisted↗
PubMed2000

[5'CpG island methylation of the suppressor gene p16/CDKN2/MTS1 in renal carcinoma].

OBJECTIVE: To determine the methylation status of the tumor suppressor gene p16 in patients with renal carcinoma by analysis of microsatellite polymorphisms. METHODS: 40 patients with sporadic renal cancer were studied. Tumor and normal tissue from each patient were tested for methylation status of the p16 gene by analysis of microsatellite polymorphisms. RESULTS: 20% showed methylation of p16. No correlation was found between this genetic alteration and tumor features. CONCLUSIONS: Methylation of p16 was found in 20% of the patients in this series. According to the analysis, 18.5% of renal cell carcinomas showed methylation, 50% of chromophobe cell carcinomas and 25% of carcinomas of Bellini's tubules. The rest of the histological types showed no methylation.

Adult↗
PubMed2000

[Loss of heterozygosity in the 9p21 region as an inactivation mechanism of the p16 suppressor gene].

OBJECTIVE: To determine the loss of heterozygosity (LOH) on 9p21 (locus D9S1747) in patients with renal carcinoma by analysis of microsatellite polymorphisms. METHODS: 40 patients with sporadic renal cancer were studied. LOH on 9p21 was performed by analysis of microsatellite polymorphisms. RESULTS: 23.7% showed LOH on 9p21. No correlation was found between this genetic alteration and tumor features. CONCLUSIONS: LOH on 9p21 was found in 23.7% of the patients in this series. LOH was found in 26.9% of renal cell carcinomas, 25% of papillary carcinomas and 25% of Bellini duct carcinomas. LOH was not found in the other histological types.

Adult↗
PubMed2000

Polymorphisms of octopine dehydrogenase (Odh) in mollusks and implications for the neutralism-selectionism hypothesis.

Octopine dehydrogenase (Odh) was examined in several species of bivalves and gastropods and complemented with bibliographic data, to assess the controversy between neutralism and selectionism in explaining the maintenance of genetic variation in natural populations. This debate was the center of the molecular evolution and population genetic research in the 1970s and 1980s, but waned thereafter, without resolution. Although DNA data have been produced, implications are not understood. We examined the polymorphims of Odh in several species of bivalves and gastropods, and the kinetic properties (apparent Km) of the different isozymes in the scallop Euvola ziczac that indicates an apparent case of overdominance of the heterozygous individuals. The question "which of the two hypothesis is correct" has shifted with time to "how much influence did each factor have in the maintenance of genetic variation".

Amino Acid Oxidoreductases↗
PubMed1999

The immune response and PBMC subsets in canine visceral leishmaniasis before, and after, chemotherapy.

Peripheral blood mononuclear cell subsets, in vitro lymphoproliferative response to leishmanial antigen, and Leishmania-specific serum antibody levels were examined in 11 dogs, naturally infected with L. infantum, and 9 healthy control dogs. A decrease in the percentage of CD4+ T-cells and an increase in the proportion of gammadelta T-cells and sIgG+ B-cells were observed during canine visceral leishmaniasis (CVL). These changes may be responsible for the marked humoral response and the absence of in vitro lymphoproliferation to mitogen and specific parasite antigens. This possibility was supported by the analysis of these subsets after treatment with amphotericin B. One month after therapy, a significant increase in the percentage of CD4+ T-cells and a decrease of gammadelta T-cells and sIgG+ B-cells were observed. At the same time, the lymphocyte blastogenesis assay with leishmanial antigen was positive and the levels of specific antibodies to Leishmania were significantly lower than before the treatment. Five months after therapy, lymphocyte proliferative response to LSA disappeared, antibody and lymphocyte subsets levels returned to those observed during CVL. Therapeutic failure in CVL is associated with the inability of antileishmanial drugs to completely revert the profound immunodepression induced by the infection and prevent relapse.

Amphotericin B↗