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Biomedical subjects

J Ramos

Publications and source records attributed to J Ramos.

At least 37 records · Page 2Linked to original sources
PubMed2001

Relationships among perceived justice, customers' satisfaction, and behavioral intentions: the moderating role of gender.

This article tested the gender differences in the relationships between perceptions of justice, customers' satisfaction, and behavioral intentions. The sample consisted of 334 subjects (205 men and 129 women) surveyed in 38 hotels located in Spain. A questionnaire was used to measure distributive, procedural, and interactional justice as well as customers' responses of satisfaction and intentions. Analysis showed that the correlation between scores for distributive justice and customers' satisfaction as well as that between distributive justice and intentions were greater for men than for women. In contrast, the sex differences in the links of procedural and interactional justice to satisfaction and intentions were not significant.

Adult↗
PubMed2001

Abnormal EEG patterns in treatment-resistant schizophrenic patients.

This study was conducted in order to compare the EEG patterns of schizophrenics who do not respond to typical neuroleptics with those who do respond under typical neuroleptic medication and a group of controls. Absolute (AP) and relative power (RP), and inter- and intrahemispheric correlations were calculated. Nonresistant schizophrenics showed lower delta RP, higher alpha 1 AP and RP and higher correlation between prefrontal areas than the resistant ones and controls. Resistant schizophrenics showed lower alpha 2 RP, lower beta 1 and beta 2 in temporal but higher beta 2 AP and RP in occipital derivations, and higher intrahemispheric correlation between Fp2 and F4 and lower between F8 and T4 than the nonresistant and controls. The resistants also showed a higher antero-posterior beta 1 and beta 2 index than the controls. We concluded that the EEG pattern showed by the nonresistants may be associated with their good neuroleptic response that was not present in the resistant schizophrenics.

Adult↗
PubMed2001

Glucose-induced activation of rubidium transport and water flux in sunflower root systems.

Excised 20-d-old sunflower roots (Helianthus annuus L. cv. Sun-Gro 393) were used to study the effect of different sugars on rubidium and water fluxes. The roots sensed and absorbed glucose from the external medium inducing the activation of rubidium accumulated in the root (Rb(+) root), the flux of exuded rubidium (J(Rb)) and, to a lesser degree, the exudation rate (J(v)). These effects were also triggered by fructose, but not by 6-deoxyglucose (6-dG), a glucose analogue which is not a substrate for hexokinase (HXK). The effect of 2-deoxyglucose (2-dG), an analogue that is phosphorylated but not further metabolized, was complex, suggesting an inhibitory effect on solute transport to the xylem. The amounts of glucose required to activate rubidium and water fluxes were similar to those previously reported to regulate different processes in other plants (0.5--10 mM). When sorbitol was used instead of glucose, neither rubidium uptake (Rb(+) root plus J(Rb)) nor J(v) was activated. It is proposed that glucose present in the root plays an important signalling role in the regulation of Rb(+) (K(+)) and water transport in plant roots.

Carbon Radioisotopes↗
PubMed2000

Regulation of expression of phospholipase D1 and D2 by PEA-15, a novel protein that interacts with them.

Phospholipase D (PLD), a signal-transducing membrane-associated enzyme, is implicated in diverse processes including apoptosis, ERK activation, and glucose transport. Prior studies have identified specific PLD activators and repressors that directly regulate its enzymatic activity. Using two-hybrid screens, we have identified PEA-15 as a PLD interactor that unexpectedly functions to alter its level of expression. PEA-15 is a widely expressed death effector domain-containing phosphoprotein involved in signal transduction, apoptosis, ERK activation, and glucose transport. The PLD1-interacting site on PEA-15 consists of part of the death effector domain domain plus additional C-terminal flanking sequences, whereas the PEA-15-interacting site on PLD1 overlaps the previously identified RhoA-interacting site. PEA-15 did not affect basal or stimulated in vitro PLD1 enzymatic activation. However, co-expression of PEA-15 increased levels of PLD1 activity. This increased activation correlated with higher PLD1 protein expression levels, as marked by faster accumulation and longer persistence of PLD1 when PEA-15 was present. PEA-15 similarly increased protein expressions level of PLD2 and co-immunoprecipitated with it. These results suggest that PEA-15 may stabilize PLD or act as a PLD chaperone. The common involvement of PEA-15 and PLD in apoptosis, ERK activation, and glucose transport additionally suggests functional significance.

Alleles↗
PubMed2000

Effects of salts on Debaryomyces hansenii and Saccharomyces cerevisiae under stress conditions.

The effect of Na+ and K+ on growth and thermal death of Debaryomyces hansenii and Saccharomyces cerevisiae were compared under stress conditions as those commonly found in food environments. At the supraoptimal temperature of 34 degrees C both cations at concentrations of 0.5 M stimulated growth of D. hansenii, while K+ had no effect and Na+ inhibited growth of S. cerevisiae. At 8 degrees C, close to the minimum temperature for growth in both species, both cations inhibited both yeasts, this effect being more pronounced with Na+ in S. cerevisiae. At extreme pH values (7.8 and 3.5) both cations at concentrations of 0.25 M stimulated D. hansenii while Na+ inhibited S. cerevisiae. K+ inhibited this yeast at pH 3.5. Thermal inactivation rates, measured at 38 degrees C in D. hansenii and at 48 degrees C in S. cerevisiae, decreased in the presence of both cations. This protective effect could be observed in a wider range of concentrations in D. hansenii. These results call the attention to the fact that not all yeasts have the same behaviour on what concerns synergy or antagonism of salt together with other stress factors and should be taken into consideration in the establishment of food preservation procedures.

Potassium↗
PubMed2000

Eleven novel APC mutations identified in Portuguese FAP families.

Germline mutations of the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant predisposition to colorectal cancer. In the present study we screened all of the exons of the APC gene in individuals belonging to 85 Portuguese FAP families. We here report eleven novel mutations which are predominantly frameshifts or single base substitutions, resulting in premature stop codons. Hum Mutat 16:178, 2000.

Adenomatous Polyposis Coli↗
PubMed2000

Potassium and sodium fluxes in the phytopathogenic fungus Fusarium oxysporum var. lini.

Rubidium uptake in potassium-starved cells followed biphasic kinetics in the micromolar and millimolar range and was independent of the temperature. In contrast, Rb(+) uptake in normal-K(+) cells followed a monophasic kinetics in the millimolar range and increased at temperatures higher than 30 degrees C. Differences in the K(m) values and in the Arrhenius plots of Rb(+) uptake suggest different uptake systems in K(+)-starved and in normal-K(+) cells. In addition, the substantial inhibition of Rb(+) uptake caused by carbonyl cyanide-m-chlorophenyl hydrazone indicates that these systems are strongly dependent on membrane voltage. Lithium (sodium) tolerance, influx, and efflux were separately studied. F. oxysporum was shown to be very tolerant to sodium, while lithium caused a specific toxic effect. Li(+) uptake in K(+)-starved cells exhibits a monophasic kinetics with low affinity. Li(+) efflux was not affected by external pH or addition of potassium to the medium, suggesting that a Na(+)/cation antiporter is not involved in this process.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed2000

Hartshill rectangle: failure of spinal stabilisation in acute spinal cord injury.

A high rate of failure of the internal fixation of unstable spinal fractures in complete cord injured patients was noted in patients referred to the Salisbury Spinal Centre who had been stabilised with a Hartshill rectangle. This prompted a review of the operative notes, radiographs and clinical outcomes of all patients referred to the centre with a Hartshill rectangle in situ. All patients identified with a complete spinal cord injury and Hartshill rectangle were identified. Forty-three such patients referred from 13 different centres were found. Pre- and postoperative radiographs were assessed for fracture pattern and for spinal correction. Operative outcome in terms of pain and complications relating to surgery were identified. The most recent radiographs were assessed for signs of loss of reduction or stabilisation. Follow-up averaged 84 months (range 36-132 months). Of the 43 identified patients, 19 were found to have unsatisfactory stabilisation. Persistent pain, broken implants and worsening kyphosis were the main complications. The failure to use bone graft at the time of stabilisation was significantly (P < 0.001) related to risk of failure. The application and use of the Hartshill is not a technically challenging procedure; however, if the system is to be used, it must be used correctly. Failure to correctly apply the rectangle and to use bone graft will lead to an unacceptably high rate of failure.

Adolescent↗
PubMed2000

LC analysis of benzophenone-3: II application to determination of 'in vitro' and 'in vivo' skin penetration from solvents, coarse and submicron emulsions.

The aim of this study was to determine the skin penetration of benzophenone-3 in vitro and in vivo in order to investigate a possible influence of formulation. Six different vehicles, three solvents and three different emulsion types were evaluated in vitro and in vivo. Each vehicle was applied to the skin model at 2 mg cm(-2). First, histological studies on ear pigskin and human skin were evaluated. In vitro measurements were performed with static diffusion cells using pigskin at 1, 2, 4, and 8-h. In vivo, benzophenone-3 concentration in stratum corneum was evaluated by the stripping method after 30-min application on forearm of volunteers. It was shown that ear pigskin and human skin appear similar and in both experiments significant differences between vehicles were noticed. The six vehicles could be ranked in the same order of benzophenone-3 skin concentration. At 8-h, the highest concentration of benzophenone-3 in skin was obtained with propylene glycol, and O/W submicron emulsion. On the contrary. the two oily solvents. W/O emulsion and O/W coarse emulsion restrain the concentration of this UV-filter in the skin. At each time, permeability in vitro and in vivo were well correlated. Low concentrations were measured in the receptor fluid suggesting that percutaneous absorption of this UV-filter across the skin would be minimal. The in vitro and in vivo skin penetration capacity of benzophenone-3 from six vehicles was confirmed and quantified. A satisfactory relationship between binary in vitro and in vivo was established.

Adult↗
PubMed2000

Degradation of Aux/IAA proteins is essential for normal auxin signalling.

The growth substance auxin mediates many cellular processes, including division, elongation and differentiation. PSIAA6 is a member of the Aux/IAA family of short-lived putative transcriptional regulators that share four conserved domains and whose mRNAs are rapidly induced in the presence of auxin. Here PSIAA6 was shown to serve as a dominant transferable degradation signal when present as a translational fusion with firefly luciferase (LUC), with an in vivo half-life of 13.5 min in transgenic Arabidopsis seedlings. In a transient assay system in tobacco protoplasts using steady-state differences as an indirect measure of protein half-life, LUC fusions with full-length PSIAA6 and IAA1, an Aux/IAA protein from Arabidopsis, resulted in protein accumulations that were 3.5 and 1. 0%, respectively, of that with LUC alone. An N-terminal region spanning conserved domain II of PSIAA6 containing amino acids 18-73 was shown to contain the necessary cis-acting element to confer low protein accumulation onto LUC, while a fusion protein with PSIAA6 amino acids 71-179 had only a slight effect. Single amino acid substitutions of PSIAA6 in conserved domain II, equivalent to those found in two alleles of axr3, a gene that encodes Aux/IAA protein IAA17, resulted in a greater than 50-fold increase in protein accumulation. Thus, the same mutations resulting in an altered auxin response phenotype increase Aux/IAA protein accumulation, providing a direct link between these two processes. In support of this model, transgenic plants engineered to over-express IAA17 have an axr3-like phenotype. Together, these data suggest that rapid degradation of Aux/IAA proteins is necessary for a normal auxin response.

Arabidopsis↗
PubMed2000

Sensitization to individual allergens as risk factors for lower FEV1 in young adults. European Community Respiratory Health Survey.

BACKGROUND: Atopy may impair ventilatory function, but results are controversial. We assess the association between individual reactivity to allergens and the level of baseline maximal one-second forced expiratory volume (FEV1), by smoking and respiratory symptoms. METHODS: The 1472 participants (response 44.5%) of the five Spanish areas of the European Community Respiratory Health Survey (ECRHS) who performed respiratory function tests, skin prick tests and/or specific IgE against common aeroallergens (e.g. mites, pets, mould, pollens) are included. Bronchial hyperreactivity (BHR) was measured with a methacholine challenge. RESULTS: After adjusting for BHR and smoking, in addition to the other allergens, skin reactivity to Alternaria (-208 ml; 95% CI :-451, 35) and IgE antibodies against cat (-124 ml; 95% CI:-269, 21) and Timothy grass (-115 ml, 95% CI:-190, -40) were associated with a decrease in FEV1 in females. Among males, skin reactivity to olive showed the strongest association (-111 ml; 95% CI: -261, 38). The associations were stronger in females. Smoking modifies the association for Alternaria and cat (P for interaction < 0.05). While cat is associated with a decrease in FEV1 in current smokers (-190 ml), Alternaria (-336 ml) was associated among never smokers. The exclusion of subjects with asthma symptoms, or adjustment for respiratory symptoms, led to similar results. CONCLUSIONS: We conclude that immunoresponse to individual allergens (particularly outdoor) is associated with the level of FEV1, and this association occurred independently of asthma, and in smokers and non-smokers, which may be of interest in natural history of chronic obstructive pulmonary disease (COPD).

Adult↗
PubMed2000

cis-Tetracarbonylbis(tricyclohexylphosphine)molybdenum(0) and pentacarbonyl(tricyclohexylphosphine)molybdenum(0)

In the present redetermination of the complex cis-tetracarbonylbis(tricyclohexylphosphine)molybdenum(0), (I), [Mo(C(18)H(33)P)(2)(CO)(4)] or cis-eta(1)-[P(C(6)H(11))(3)](2)Mo(CO)(4), the Mo atom has a distorted octahedral geometry with a large P-Mo-P angle of 104.8 (1) degrees. A strong trans influence on the carbonyls in (I) is seen in a shortening of the Mo-C and a lengthening of the C-O distances opposite the phosphines compared with those that are cis. This influence is greatly diminished in the complex pentacarbonyl(tricyclohexylphosphine)molybdenum(0), (II), [Mo(C(18)H(33)P)(CO)(5)] or eta(1)-[P(C(6)H(11))(3)]Mo(CO)(5), the core of which has a slightly distorted C(4v) geometry.

Journal Article↗
PubMed2000

Trk1 and Trk2 define the major K(+) transport system in fission yeast.

The trk1(+) gene has been proposed as a component of the K(+) influx system in the fission yeast Schizosaccharomyces pombe. Previous work from our laboratories revealed that trk1 mutants do not show significantly altered content or influx of K(+), although they are more sensitive to Na(+). Genome database searches revealed that S. pombe encodes a putative gene (designated here trk2(+)) that shows significant identity to trk1(+). We have analyzed the characteristics of potassium influx in S. pombe by using trk1 trk2 mutants. Unlike budding yeast, fission yeast displays a biphasic transport kinetics. trk2 mutants do not show altered K(+) transport and exhibit only a slightly reduced Na(+) tolerance. However, trk1 trk2 double mutants fail to grow at low K(+) concentrations and show a dramatic decrease in Rb(+) influx, as a result of loss of the high-affinity transport component. Furthermore, trk1 trk2 cells are very sensitive to Na(+), as would be expected for a strain showing defective potassium transport. When trk1 trk2 cells are maintained in K(+)-free medium, the potassium content remains higher than that of the wild type or trk single mutants. In addition, the trk1 trk2 strain displays increased sensitivity to hygromycin B. These results are consistent with a hyperpolarized state of the plasma membrane. An additional phenotype of cells lacking both Trk components is a failure to grow at acidic pH. In conclusion, the Trk1 and Trk2 proteins define the major K(+) transport system in fission yeast, and in contrast to what is known for budding yeast, the presence of any of these two proteins is sufficient to allow growth at normal potassium levels.

Amino Acid Sequence↗
PubMed2000

Liver iron excess in patients with hepatocellular carcinoma developed on viral C cirrhosis.

BACKGROUND: Liver iron deposits are frequent in viral C cirrhotic patients but their role is not well defined. AIMS: To investigate the effect of liver iron excess on the prevalence of hepatocellular carcinoma (HCC) in patients with viral C cirrhosis. METHODS: Hepatic iron was evaluated retrospectively using a semiquantitative method in liver biopsies of 104 viral C cirrhotic patients, 48 with HCC and 56 controls (HCC free). Corrected total iron score (0-60) was defined by the sum of three scores: hepatocytic iron score (0-36), sinusoidal iron score (0-12), and portal iron score (0-12), multiplied by 3/3, 2/3, or 1/3 according to the heterogeneous iron localisation in the nodules. RESULTS: After adjustment for known risk factors for HCC, regression analysis showed that iron deposits (corrected total iron score >0) were more frequent in HCC patients than in controls (odds ratio 4.94; 95% confidence interval 1.59-15. 32; p=0.0056). The median of corrected total iron score was significantly higher in HCC patients than in controls (odds ratio 1. 092; 95% confidence interval 1.01-1.13; p=0.021). This liver iron overload was sinusoidal (odds ratio 5.2; 95% confidence interval 1. 82-15.11; p=0.0022). CONCLUSIONS: Liver iron deposition was more frequent and more important in viral C cirrhotic patients with HCC than in HCC free controls. Liver iron overload seems to contribute to the development of HCC in patients with viral C cirrhosis.

Adult↗
PubMed2000

Congenital cystic disease of the liver and kidney in a pygmy goat.

A 1-month-old pygmy goat was presented with abdominal distension and hematuria. Anemia, leukocytosis, and increased bilirubin and blood urea nitrogen levels suggested renal and hepatic disease. Radiographs revealed bilateral renomegaly, and ultrasound confirmed bilateral hydronephrosis. Necropsy findings determined that the renomegaly was due in part to edema and marked cystic tubular distension. Similarly, intrahepatic bile ducts were ectatic. The character and distribution of the gross and histologic lesions were consistent with a polycystic disorder, presumably congenital, affecting the liver and the kidney.

Animals↗
PubMed1999

High-grade carcinoma component in epithelial-myoepithelial carcinoma of salivary glands clinicopathological, immunohistochemical and flow-cytometric study of three cases.

Three cases of epithelial-myoepithelial carcinoma (EMC) with coexisting areas of high grade carcinoma are reported. In two of the cases there was a previous recurrence, and in all three patients there had been a sudden increase in size before final surgery. The typical ductal and myoepithelial components of EMC showed the usual biphasic pattern and the expected immunophenotypes, with expression of wide spectrum cytokeratins, Cam 5.2 and EMA in the ductal part, and muscle-specific actin, smooth muscle actin, S-100 protein, vimentin and cytokeratins in the myoepithelial component. These areas also had a low mitotic count and low proliferation rate as measured by immunohistochemistry and by flow cytometry. Conversely, areas of high-grade tumour had the features of a large cell carcinoma, with focal mucin secretion in two cases. This high-grade component showed an epithelial immunophenotype in two cases, and was negative for all tested markers in the third one. The mitotic counts and the proliferation rates were much higher in these anaplastic areas. One of the patients died 3 months after treatment; another developed lymph node metastases 1 year later and was alive after 6 years of follow-up. The third patient was alive without evidence of disease 7 months after wide surgical resection of the tumour. The possibility of anaplastic transformation in EMC makes thorough sampling mandatory in this type of neoplasm.

Aged↗