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Biomedical subjects

A Ortega

Publications and source records attributed to A Ortega.

At least 55 records · Page 3Linked to original sources
PubMed2001

Incremental validity of the MMPI-2 Content Scales: a preliminary study with brain-injured patients.

OBJECTIVE: To examine the usefulness of the MMPI-2 Content Scales among traumatic brain injury (TBI) patients. DESIGN: Hierarchical stepwise regression analyses with the SCL-90-R scales as the criterion variables were conducted to determine the incremental validity of the Content Scales beyond the information provided by the Clinical Scales. PARTICIPANTS: 27 persons with moderate to severe TBI who had been discharged to the community from inpatient rehabilitation between 6 months and 4 years before the beginning of the study. RESULTS: The Content Scales accounted for an additional 4% to 36% of the variance of SCL-90-R scales beyond that predicted by the Clinical Scales. CONCLUSIONS: Interpretation of the Content Scales may be particularly valuable with TBI patients, because they provide an additional avenue for the identification of distressing symptoms.

Adult↗
PubMed2001

Alpha-vascular responses after short-term and long-term inhibition of nitric oxide synthesis.

Apart from the direct actions of nitric oxide (NO) on vascular smooth muscle, this factor may regulate cardiovascular functions through specific actions on alpha-adrenergic constrictor mechanisms. In this study we aim to establish whether the inhibition of the synthesis of this mediator could alter the vasoconstrictor responses mediated by alpha-adrenoceptor stimulation. We have been able to demonstrate that the blockage of the NO synthase really does exist, when both short- and long-term treatments with Nomega-nitro-Larginine methyl ester (L-NAME) are carried out. We have evaluated the concentration-dependent contractions induced by the selective alpha1-adrenoceptor agonists methoxamine and phenylephrine in isolated rat aorta rings in the following groups of animals: control, short-term L-NAME-treated (100 mg/kg i.p. 20 min before subjecting the animals to the experiments) and long-term L-NAME-treated (100 mg/kg per day in the drinking water for 7, 21, or 45 days). We have also evaluated the pressor responses to methoxamine and to the selective alpha-adrenoceptor agonist B-HT 920 using the pithed rat preparation in the same groups of animals. The contractile responses to methoxamine and phenylephrine were similar in the rat aorta preparations from control and short-term L-NAME-treated animals. On the contrary, in the rat aorta preparations from long-term L-NAME-treated animals these responses were clearly reduced when compared with the corresponding responses in those from control animals, the reduction being more marked when the treatment lasted longer. The pressor responses to methoxamine were also similar in control and short-term L-NAME-treated pithed rats. Nevertheless, the responses to B-HT 920 were greater in the latter. On the other hand, the dose-response curves to both alpha-adrenoceptor agonists were shifted to the right in a non-parallel manner in rats treated long term with L-NAME, the shift being, in the case of B-HT 920, more accentuated when the treatment lasted 21 or 45 days than when it lasted only 7 days. These results indicate that the short-term decrease in NO synthesis does not modify the vascular smooth muscle responses mediated by alpha1-adrenoceptor stimulation, but it does induce a potentiation of sympathetic vasoconstriction mediated by alpha2-adrenoceptors. Nevertheless, the long-term inhibition of NO synthesis causes a compensating decrease in the alpha1- and alpha2-vascular smooth muscle contractile responses.

Adrenergic alpha-Agonists↗
PubMed2001

A multinational study to measure the value that patients with cancer place on improved emesis control following cisplatin chemotherapy.

BACKGROUND: The neurokinin-1 (NK1) receptor antagonists are a new class of agents designed to reduce the risk of emesis following chemotherapy, particularly with cisplatin. Early data from double-blind randomised trials suggest that an orally administered NK1 antagonist can reduce the absolute risk of acute and delayed emesis following cisplatin by 20 and 30%, respectively. OBJECTIVE: To measure the value that patients with cancer place on improved emesis control and quality of life. DESIGN: Willingness-to-pay analysis. SETTING: Five study sites in Canada, Italy, Spain and Greece. PATIENTS AND PARTICIPANTS: 245 patients with cancer either receiving chemotherapy with cisplatin or who had received cisplatin-based chemotherapy within the previous 6 months. METHODS: After background information had been presented, patients were asked to define the maximum that they would pay per day for a drug that reduced their risk of acute and delayed (days 2 to 5) emesis by 20 and 30%, respectively. Costs were converted to US dollars ($US) using year 2000 exchange rates. RESULTS: For a 20% improvement in acute emesis, Canadian, Italian and Spanish patients with cancer were willing to pay $US46, $US34 and $US63 per day, respectively, compared with $US8 for patients from Greece (p < 0.001). For a 30% improvement in delayed emesis, Canadian, Italian and Spanish patients with cancer were also willing to pay more than their Greek counterparts (SUS41, $US31, $US50 and $US9 daily for 4 days, respectively; p < 0.001). These significant differences in patient value between countries remained, even after adjusting for socioeconomic variables and previous history of emesis. CONCLUSIONS: There are substantial cultural differences in how patients with cancer value benefit and improved quality of life. Since the majority of the world's population resides outside North America and Western Europe, there may be a need to re-evaluate perceived levels of patient benefit and measures of quality of life.

Antiemetics↗
PubMed2001

[Meaning of clinical and electrical positivity in the myocardial perfusion scintigraphy during the administration of dipyridamole].

BACKGROUND AND OBJECTIVES: Administration of dipyridamole produces angina and ST depression in 20%-30% and 6%-34% of patients, respectively. This study aimed to evaluate the clinical implications of the presentation of angina and/or ST depression during the administration of dipyridamole in the study of coronary heart disease by myocardial perfusion SPECT (MPS). METHODS: The study population is constituted by 593 consecutive patients without left branch block or ventricular pacemaker rhythm who were referred to our service to undergo MPS with dipyridamole. A SPECT was performed after the administration of 99mTc-tetrosfosmine and drug stimulation with dipyridamole (0.142 mg/kg/min for 4 minutes). A coronariography was performed in 338 patients (57%). The frequency of clinical and electrical positivity and their relationship with the MPS and the coronariography were studied. RESULTS: The rate of angina and ST depression was 32% (n = 190) and 10% (n = 58), respectively. Myocardial perfusion defects were observed in 465 patients (78%), and signs of scintigraphic ischemia in 311 (52%). The patients with ST depression presented a higher frequency of perfusion defects (93% vs 76%, p = 0.0012) and scintigraphic ischemia (89% vs 49%, p < 0.0001). In addition, perfusion defects in more than one territory were observed in these patients in a higher percentage (53% vs 34%, p = 0.0036). Among the patients who underwent cardiac catheterization, those who had a ST depression had a greater extension of coronary heart disease (1.8 +/- 1.2 vs 1.3 +/- 1.0 diseased vessels, respectively. p = 0.0100) and a higher frequency of multivessel disease (61% vs 43%, p = 0.0380). Those patients who had clinical positivity showed a scintigraphic ischemia more frequently (66% vs 47%, p < 0.0001), however no statistically significant differences were observed between the presence of patients with perfusion defects or in the extension of these defects as well as in the number of diseased vessels in the coronariographic study. CONCLUSIONS: During the administration of dipyridamole, the ST depression is associated with more frequent scintigraphic ischemia, larger extension of perfusion defects and more diseased vessels. The appearance of angina is associated with scintigraphic ischemia, but it is not necessarily associated with the extension of perfusion defects or greater number of diseased vessels.

Angina Pectoris↗
PubMed2001

[Consensus conference on consultation times in neurology. Recommendations on consultation times in neurology outpatients care in Spain].

INTRODUCTION: Developing recommendations about consultation times in neurology helps plan the endowment of human resources and can contribute to homogenize and improve quality of health-care. OBJECTIVES: To elaborate recommendations on the consultation times needed to obtain enough quality neurology visits. MATERIAL AND METHOD: We used consensus search techniques, in particular the Community Impression technique. An ad hoc committee developed a preliminary proposal which was later discussed during a unlimited attendance working meeting and eventually voted by members of the Spanish Society of Neurology. The committee drew up a final consensus report after analysing the debate results and counting the ballots. FINAL RECOMMENDATION: "It is necessary that the Spanish Society of Neurology establishes and recommends standardized consultation times for neurology outpatients visits in Spain. These standardized values refer to consultation time per patient, both in the first and follow-up visits, in a General Neurology Outpatients Clinic. Moreover, there must be considered 'recommendable times' on one hand, and 'minimal required times' on the other hand. Any time value below the minimal required time means that the consultation duration does not fulfill the minimal requirements needed to warrant a care with acceptable quality for the patient". These recommendations are: Time for first consultation. Recommendable time: 45 minutes (Minimal required time: 25 minutes). Time for follow-up consultation. Recommendable time: 20 minutes (Minimal required time: 15 minutes).

Humans↗
PubMed2000

Glutamate regulates kainate-binding protein expression in cultured chick Bergmann glia through an activator protein-1 binding site.

The expression of the chick kainate-binding protein, a member of the ionotropic glutamate receptor family, is restricted to the cerebellum, specifically to Bergmann glia. Glutamate induces a membrane to nuclei signaling involved in gene expression regulation. Exposure of cultured chick Bergmann glia cells to glutamate leads to an increase in kainate binding protein and mRNA levels, suggesting a transcriptional level of regulation. The 5' proximal region of the chick kainate binding gene was cloned and transfected 4into Bergmann glia cells. Three main regulatory regions could be defined, a minimal promoter region, a negative regulatory region, and interestingly, a glutamate-responsive element. Deletion of this element abolishes the agonist effect. Moreover, electrophoretic mobility shift assays, cotransfection experiments, and site-directed mutagenesis clearly suggest that the glutamate effect is mediated through an AP-1 site by a Fos/Jun heterodimer. The present results favor the notion of a functional role of kainate-binding protein in glutamatergic cerebellar neurotransmission.

Animals↗
PubMed2000

GLAST: gene expression regulation by phorbol esters.

The gene expression regulation of the Na+-dependent high affinity glutamate/aspartate transporter GLAST expressed in cultured Bergmann glia cells from chick cerebellum was studied. A 679 bp fragment of the chick GLAST cDNA was cloned and sequenced. Specific PCR primers were used to quantify chick GLAST mRNA levels. Treatment of the cells with the Ca2+/diacylglycerol dependent protein kinase C (PKC) activator, phorbol 12-tetradecanoyl-13-acetate (TPA) produced a decrease in transporter mRNA levels, without an effect in its mRNA half life, suggesting a transcriptional down regulation. Activation of the cAMP pathway results in a transient decrease in GLAST mRNA levels, in contrast with the TPA effect. These findings suggest that GLAST expression is under control of distinct signaling pathways.

ATP-Binding Cassette Transporters↗
PubMed2000

Regulation of high-affinity glutamate uptake activity in Bergmann glia cells by glutamate.

The effect of glutamate receptor activation on the high-affinity sodium-dependent glutamate transport expressed in chick Bergmann glia cells was examined. Pre-exposure to glutamate produced a time- and dose-dependent decrease in 3H-labeled D-aspartate uptake. This effect could not be reproduced by selective glutamate receptor agonists. Furthermore, it was insensitive to both ionotropic and metabotropic glutamate receptor antagonists. Replacement of extracellular sodium ions with choline in the preincubation media, abolished the reduction of the uptake. When the cells were pre-exposed to competitive transportable inhibitors of the transporter, such as D-aspartate, DL-threo-hydroxyaspartate (DL-THA), and aspartate-beta-hydroxamate (ABH), the glutamate effect was mimicked. From saturation experiments, it was found that the reduction on the uptake, after glutamate treatment, is related to an increase in K(m). Interestingly, the effect is blocked by staurosporine, a Ca(2+)/diacylglycerol-dependent protein kinase (PKC) inhibitor. The present findings suggest that glutamate regulates its transport in a non-receptor fashion, a phenomena that is most probably linked to changes induced by the translocation process of the substrate through the transporter.

Animals↗
PubMed2000

Acoustic analysis after radiotherapy in T1 vocal cord carcinoma: a new approach to the analysis of voice quality.

PURPOSE: The study of acoustic voice parameters (fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio) in extended vowel production, oral reading of a standard paragraph, spontaneous speech and a song in irradiated patients for Tis-T1 vocal cord carcinoma. METHODS AND MATERIALS: Eighteen male patients irradiated for Tis-T1 vocal cord carcinoma and a control group of 31 nonirradiated subjects of the same age were included in a study of acoustic voice analysis. The control group had been rigorously selected for voice quality and the irradiated group had previous history of smoking in two-thirds of the cases and a vocal cord biopsy. Radiotherapy patients were treated with a 6MV Linac receiving a total dose of 66 Gy, 2 Gy/day, with median treatment areas of 28 cm(2). Acoustic voice analysis was performed 1 year after radiotherapy, the voice of patients in extended vowel production, oral reading of a standard paragraph, spontaneous speech, and in a song was tape registered and analyzed by a Kay Elemetric's Computerized Speech Lab (model CSL# 4300). Fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio were obtained in each case. Mann Whitney analysis was used for statistical tests. RESULTS: The irradiated group presented higher values of fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio. Mann-Whitney analysis showed significant differences for fundamental frequency and jitter in vowel production, oral reading, spontaneous speech, and song. Shimmer only showed differences in vowel production and harmonics-to-noise ratio in oral reading and song. CONCLUSIONS: In our study only fundamental frequency and jitter showed significant increased values to the control group in all the acoustic situations. Sustained vowel production showed the worst values of the acoustic parameters in comparison with the other acoustic situations. This study seems to suggest that more work should be done in this field.

Aged↗
PubMed2000

Blood strontium concentration related to the length of the agonal period in seawater drowning cases.

The levels of ventricular blood strontium (Sr) from 70 seawater drowning victims were compared with their diagnosis of drowning based mainly on certain criteria selected from their autopsy report. From this comparison, intervals of either the difference of Sr concentration between the left and the right ventricle blood (LVSr-RVSr) or the Sr concentration in the left ventricle blood (LVSr), appear to be related to different time-lapses of the agonal period of drowning. In the aim to diagnose drownings, intervals of both LVSr-RVSr and LVSr were proposed to characterize three different agonal periods in seawater drowning cases: instantaneous death (ID), fast vital-submersion drowning (FVSD) and common vital-submersion drowning (CVSD).

Diagnosis, Differential↗
PubMed2000

Polystachynes A-E, five cis-neo-clerodane diterpenoids from Salvia polystachya.

From the aerial parts of Salvia polystachya five new neo-clerodane diterpenoids, polystachynes A-E, have been isolated. The structures were established by spectroscopic methods, including the X-ray analysis of polystachynes C and D. The known clerodanes salvifaricin, linearolactone and dehydrokerlin were also isolated.

Crystallography, X-Ray↗
PubMed2000

Microcomputer program for automated action potential waveform analysis.

A program for action potential waveform analysis based on a PC compatible computer is described. Single or averaged action potentials are analyzed by obtaining its first derivative and using criteria which allow automatic measurement of several action potential components, including: depolarization rate, repolarization rate, amplitude, duration, resting membrane potential and afterhyperpolarization amplitude and slope. Data can be imported from pClamp (Axon Instruments) and exported to other software such as Excel, Sigmaplot and MatLab for example.

Action Potentials↗
PubMed2000

[Results of myocardial scintigraphy with 99mTc-tetrofosmin and dipyridamole administration in patients diagnosed of microvascular angina].

The objective of the study was to evaluate the results of the myocardial scintigraphy with 99mTc-tetrofosmin (Tc-Tf) and pharmacological stimulation with dipyridamole in patients diagnosed of microvascular angina. The study population is made up of 50 patients discharged with the diagnosis of microvascular angina who had undergone Tc-Tf-dipyridamole. Clinical and electrical positivity appeared in 40% and 12% of the patients, respectively. Myocardial perfusion defects were found in 35 patients (70%), and were reversible in 21 (60%), fixed in 11 (21%), and combined in 3 (9%). Abnormalities were inferior, anteroseptal and lateral in 21, 18, and 2 patients, respectively. Patients with a positive exercise treadmill test, compared with those with a negative one, had more frequent perfusion abnormalities (91% vs 50%, p = 0.0327) and myocardial ischemia (64% vs 20%, p = 0.392). Women, in comparison with men, had angina (56% vs 22%, p = 0.013), and anteroseptal perfusion abnormalities (26% vs 4%, p = 0.028) more frequently. On the contrary, men had inferior perfusion abnormalities more frequently (57% vs 30%, p = 0.057). Thus, Tc-Tf-dipyridamole shows perfusion abnormalities in 70% of patients with microvascular angina (91% in patients with a positive exercise treadmill test). Scintigraphic pattern may be partially conditioned by gender in these patients.

Coronary Circulation↗
PubMed2000

[Bone scintigraphy findings in patients with recently diagnosed adenocarcinoma of the prostate: relationship with prostate specific antigen levels].

BACKGROUND AND OBJECTIVES: Although it has been suggested that bone scintigraphy (BS) may not be necessary in patients with prostate adenocarcinoma (PA) and normal prostate specific antigen (PSA) plasma levels, controversy still remains. The objective of the study was to evaluate the existing relationship between PSA plasma levels and BS findings in patients with a recently diagnosed PA in order to assess whether BS may be omitted on the basis of the PSA levels in these patients. METHODS: The 475 patients (70+/-7 years old) consecutively diagnosed of PA between 1994 and 1998 in our institution made up the study population. PSA plasmatic levels were determined and BS was performed (body planar study after 99mTc-methyl diphosphonate 900 MBq administration) in all the patients. RESULTS: In 362 patients (76.2%), BS was negative, in 108 (22.7%) positive and undetermined in the remaining 5 patients (1.1%). The mean PSA level in the whole study population was 74+/-267 ng/ml (range 0.4-4.200) and was higher in patients with positive GO (218+/-512 vs 31+/-89, p<0,0001). As PSA increased, the rate of patients with positive BS was significantly higher, this being 0%, 16.4%, 9.7%, 14.0%, 31.0% and 48.3% in patients with PSA 4, 4.1-10; 10.1-20; 20.1-30; 30.1-40, and >40 ng/ml, respectively (p<0.0001). In patients with positive BS, the PSA levels were 20 and 10 ng/ml in 30.6% and 18.6% of the patients, respectively. CONCLUSION: According to our experience, there is a significant association between PSA plasma levels and the BS results in patients with recently diagnosed PA. However, a significant proportion of patients with bone metastasis have normal PSA levels, and therefore BS should be performed in all patients with recently diagnosed PA regardless of the PSA levels.

Aged↗
PubMed2000

Cost analysis of neuromuscular blocking agents in the operating room: cisatracurium, atracurium, vecuronium and rocuronium.

Cisatracurium (C), Atracurium (A), Rocuronium (R) and Vecuronium (V) are four neuromuscular blockers (NMB) used in the operating room with similar efficacy, defined as adequate muscle relaxation, but different pharmacokinetics. C and A have organ-independent elimination, A is associated with histamine release and R has a shorter onset time. The objective of this study was to economically compare these four NMB from the hospital point of view in order to facilitate drug selection. A cost analysis was performed. Only direct costs were considered and data were collected through a retrospective chart review. A total of 151 patient charts were randomly selected. Differences between patients receiving one of the four NMB were evaluated by ANOVA or Kruskal-Wallis tests. Then a multiple linear regression analysis was conducted. In the chart review, no significant difference was observed between the four groups of patients in age, weight or surgery duration (p > 0.05). Multiple regression analysis revealed that atracurium was on average PTA 237 (1 Euro = PTA 166) cheaper per surgery than any other NMB after adjusting for other factors (p < 0.01) and there is no significant difference in cost between the other three NMBs (p > 0.1). We recommend the use of rocuronium when a quick onset is needed and the patient does not have hepatic failure, cisatracurium when a haemodynamic instability is possible and atracurium in the remaining cases. If just one NMB can be included in the drug formulary we would select cisatracurium due to its pharmacological advantages over atracurium with a small increment in cost.

Adult↗