Search PubMed⌕ Search

Biomedical subjects

E Ramos

Publications and source records attributed to E Ramos.

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

Targeting the basal ganglia for deep brain stimulation in Parkinson's disease.

The revitalization of surgery for Parkinson's disease (PD) has fueled discussion about the best methodology to define the target. Placement of electrodes for deep brain stimulation (DBS) requires the usual stereotactic technique but the argument is mainly centered on whether or not microrecording neuronal activity is necessary. We compared the accuracy of calculating the coordinates X (medio-lateral) and Y (rostro-caudal) considered by the classic stereotactic method, i.e., definition of the AC-PC intercomissural line by MRI and a digitized version of the Schaltenbrand's atlas, with final electrode placement according with microrecording and microstimulation in 21 patients. For both the globus pallidum internum (GPi) (n = 21) and the subthalamic nucleus (STN) (n = 36) there was, respectively, a 43% and 45% mismatching of more than 3 mm between the theoretic coordinates and the final site of electrode location. This applies to both the X and Y planes. Accuracy was not improved in patients (n = 11) in whom the bilateral procedure was undertaken in a single day. We conclude that proper electrode positioning of the STN and GPi requires fine electrophysiologic assessment.

Adult↗
PubMed2000

Deep brain stimulation of the globus pallidus pars interna in advanced Parkinson's disease.

Pallidotomy is now widely performed for the treatment of advanced Parkinson's disease (PD). Preliminary reports of the effect of globus pallidus pars interna deep brain stimulation (GPi DBS) have also been promising. We have analyzed a cohort of 22 consecutive patients enrolled in a multicenter study. Surgery was bilateral in 17 and unilateral in five patients. At 6-month follow-up, the bilaterally GPi-implanted patients demonstrated a marked improvement when examined after drug withdrawal ("off") and under optimal medication ("on") using the Unified Parkinson's Disease Rating Scale (UPDRS). The benefit induced by the stimulation in the "off" medication condition in the total motor score was 31% and in the activities of daily living (ADL) scores was 39%. During the "on" medication period, the reduction in the total "on" dyskinesias score was 66% and in the ADL score was 32%. A similar pattern of improvement was seen in the group of patients with unilateral GPi stimulation, although a second cohort of 12 patients not included in the multicenter study showed greater improvements in "on" motor functioning. Although the effect of DBS is predominantly reversible, electrode insertion alone resulted in measurable clinical effects in the absence of stimulation. Thus, at 6-month follow-up, the benefit observed without stimulation was up to 44% in the "on" dyskinesias score and 29% in timed tapping scores undertaken in the "off" medication state. Complications among 34 patients from all centers included perioperative infection (n=3), hardware fracture (n=2), and premature battery failure (n=3). These results show a positive antiparkinsonian effect of pallidal DBS. No specific complications were observed with bilateral procedures.

Adult↗
PubMed2000

Bilateral deep brain stimulation of the subthalamic nucleus in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is rapidly becoming the preferred surgical choice for the treatment of advanced Parkinson's disease (PD). We report initial results in 15 patients after 12 months and in nine patients evaluated between 30 and 36 months postoperatively. Our experience confirms the robust antiparkinsonian effect of DBS of the STN in advanced PD. The severity of "off" episodes, as assessed by the Unified Parkinson Disease Rating Scale (UPDRS), was drastically reduced by 74% at 12 months, and dyskinesia scores (Dyskinesia Rating Scale) decreased. The levodopa daily dose was reduced by 55% at 12 months. A double-blind assessment to determine the effect of stimulation performed in nine patients at 3 months in the "off" medication condition was very significant (p<0.05). Nine patients have been followed for 3 years with maintained efficacy in the UPDRS "off" score and the dyskinesia score. The experience of other groups using a similar technique is reviewed. The overall assessment indicates a high antiparkinsonian effect of DBS of the STN even in advanced patients. The existence of a learning curve for this procedure should be taken into account when initial results are evaluated.

Electric Stimulation Therapy↗
PubMed1999

Vaccination against ticks (Boophilus spp.): the experience with the Bm86-based vaccine Gavac.

The control of tick infestations and the transmission of tick-borne diseases remain a challenge for the cattle industry in tropical and subtropical areas of the world. Traditional control methods have been only partially successful and the parasites continue to result in significant losses for the cattle industry. Recently, vaccines containing the recombinant B. microplus gut antigen Bm86 have been developed. Our vaccine formulation (Gavac, Heber Biotec S.A., Havana, Cuba) has been registered and is commercially available in Cuba, Colombia, Dominican Republic, Brazil and Mexico. In controlled pen trials, Gavac has been effective for the control of artificial infestations of B. annulatus, B. decoloratus and chemical-sensitive and resistant B. microplus strains from Australia, Africa, America and Iran. In controlled field trials in Cuba, Brazil, Argentina and Mexico, Gavac has shown a 55-100% efficacy in the control of B. microplus infestations in grazing cattle 12-36 weeks after the first vaccination. Field trials under production conditions have been conducted in Cuba, Colombia, Brazil and Mexico in pure and cross-bred cattle herds. The application of Gavac has increased the time between acaricide treatments by an average of 32 /-21 days (P = 0.0005) resulting in important savings for the cattle industry. In Cuba, a cost-effectiveness analysis was conducted in more than 260000 animals. The cost-effectiveness analysis showed a 60% reduction in the number of acaricide treatments, together with the control of tick infestations and transmission of babesiosis, which resulted in savings of 23.4 dollars animal(-1) year (-1). These results clearly demonstrate the advantage of vaccination and support the application of Gavac for the control of Boophilus spp. infestations.

Animals↗
PubMed1999

Stereotactic targeting of the globus pallidus internus in Parkinson's disease: imaging versus electrophysiological mapping.

OBJECTIVE: The reintroduction of pallidotomy for the treatment of Parkinson's disease (PD) has generated various opinions regarding the ideal anatomic or physiological location of the target within the globus pallidus. The role of microelectrode recording guidance in pallidotomy for the treatment of advanced PD is presently under debate. The purpose of this study was twofold. The first goal was to determine the degree of accuracy in the targeting of the globus pallidus internus (GPi) with magnetic resonance imaging (MRI), by comparing these results with the final placement of the thermolytic lesions (as defined by electrophysiological assessment). The second goal was to ascertain the somatotopic arrangement of the GPi in PD. METHODS: The analysis involved 50 patients with PD who underwent microrecording-guided pallidotomy. The theoretical coordinates for lesioning were calculated after definition of the intercommissural line by MRI. The actual placement of the lesions was determined after mapping of the GPi by microrecording, using stimulation to identify the sensorimotor region and its somatotopic organization. RESULTS: In most cases, the lesions were placed posterior and lateral to the targets chosen by MRI. Mapping by microrecording revealed differences of 2.3 +/- 1.55 mm and 3 +/- 1.9 mm in the mediolateral and anteroposterior coordinates, respectively. The actual lesion overlapped the theoretical target for only 45% of the patients. The somatotopic organization of the GPi was analyzed. Most of the units with sensorimotor activity or tremor-related activity were in the lateral portion of the nucleus. Upper limb and axial units were in the most lateral region and mainly in the ventral one-third of the nucleus. Lower limb responses were recorded mainly in the dorsal one-third of the nucleus. Tremor-related cells were found throughout the sensorimotor region of the nucleus. CONCLUSION: These results indicate that lesion targeting based on MRI alone is not sufficiently accurate to guarantee placement of the lesion in the sensorimotor region of the GPi.

Adult↗
PubMed1999

Acute myocardial infarction: psychosocial and cardiovascular risk factors in men.

BACKGROUND: Controversy still exists over the independent role of psychosocial factors in acute myocardial infarction (AMI). This study aimed to compare psychometric indices in Portuguese patients surviving a first episode of AMI and a community sample free of AMI. DESIGN: A community-based, case-control study. The study sample included 153 male patients with a first episode of AMI and 156 male controls randomly selected from the community. METHODS: Information on demographic, social, medical and behavioural characteristics was obtained using a structured questionnaire; anthropometric, blood pressure, and serum measurements were performed, and the psychometric evaluation was obtained using a self-evaluation questionnaires (Bortner scale, Beck Depression Inventory, SCL-90-R, Psychological General Well-Being and the Nottingham Health Profile). RESULTS: Cases of AMI more often exhibited type A behaviour (15.4 +/- 3.0 versus 14.7 +/- 2.7, P = 0.041), had more depressive symptoms (10.8 +/- 8.0 versus 8.6 +/- 8.0, P = 0.005) and showed worse scores on general well-being (68.4 +/- 17.7 versus 76.6 +/- 16.2, P < 0.001) than controls. Cases were significantly different from controls in terms of years of education (6.7 +/- 4.4 versus 9.0 +/- 4.7 years, P < 0.001), hypertension (43.1% versus 30.1%, P = 0.024), dislipidaemia (43.8% versus 34.0%, P = 0.038), type I obesity (53.6% versus 42.3%, P = 0.045), smoking (54.1% versus 26.5%, P < 0.001), no practise of exercise (68.5% versus 50.3%, P = 0.002) and presence of non-insulin-dependent diabetics (16.3% versus 6.4%, P = 0.010). After adjusting for such factors a similar set of significant psychometric results was found. CONCLUSION: Type A behaviour, depression and lower levels of well-being and quality of life, independent of other cardiovascular risk factors, were significant features of AMI cases.

Adult↗
PubMed1999

Upper-body adiposity and risk of myocardial infarction.

BACKGROUND: The relation between obesity and coronary heart disease (CHD) has long been studied, but no convincing conclusion has been drawn. OBJECTIVE: To estimate the relative risk associated with upper-body adiposity which is at present believed to be a better predictor of CHD. DESIGN: This was a community-based case-control study. METHODS: We studied 338 consecutively admitted patients who had had their first acute myocardial infarction (AMI) and 662 community controls who had not suffered AMI selected as a random sample of adults living in the catchment area of the hospital. We defined three classes of body mass index (BMI) and waist: hip circumference ratio on the basis of tertiles of distribution for controls. Odds ratios (OR) were estimated using unconditional logistic regression. Separate models were built for men and women. RESULTS: In univariate analysis we found a higher risk of AMI for men and women with hypertension, dyslipidaemia, diabetes and lower levels of education, for older women, for male smokers and for men with family histories of CHD. Both for men and for women a higher BMI was associated with a slightly higher risk, whereas the adjusted risk of AMI increased with increasing waist: hip circumference ratio [for men OR (second tertile)= 2.5, 95% confidence interval (CI) 1.3-4.9 and OR (third tertile)= 11.1, 95% CI 6.0-20.6; for women OR (second tertile) = 3.0, 95% CI 0.6-14.8 and OR (third tertile) = 14.1,95% CI 3.2-62.7]. This relation held for each BMI class and was stronger for classes of lower BMI. CONCLUSIONS: Distribution of body fat rather than BMI is a strong marker of risk for AMI and there is a clear interaction between these two variables.

Adult↗
PubMed1999

Neonatal cerebral Doppler: arterial and venous flow velocity measurements using color and pulsed Doppler system.

OBJECTIVE: To contribute to the establishment of reference values of blood flow velocity assessed by cerebral Doppler in healthy infants related to gestational age and birth weight during the first week of life. METHODS: Five arteries and three veins were evaluated respectively in 120 (74 premature) newborns and in 100 (70 preterm) infants. In a quarter of the latter three recordings at 5-minute intervals were made to assess reproducibility. The relation between flow measurements and gestational age was assessed by linear regression, means by analysis of variance (or Kruskall-Wallis test) and paired samples by Student's t test. RESULTS: There was a significant increase of arterial velocities with increasing gestational age and birth weight, but not for venous velocities. Significant higher values were found in the internal carotid artery followed by the medium cerebral artery. The venous velocities were highly reproducible and the main patterns observed were bandlike and sinusoid type. CONCLUSION: The knowledge of normal cerebrovascular physiology is essential to understand the pathogenesis of neonatal brain damage and can help pediatricians in an accurate interpretation of the flow profile in neurological pathology.

Arteries↗
PubMed1999

[Pallidotomy in the treatment of complicated Parkinson's disease: clinical results at two years and analysis of prognostic factors].

BACKGROUND: There is a renewed interest in pallidotomy as a treatment for complicated Parkinson's disease (PD). AIM: To present the clinical results as well as the analysis of prognostic factors obtained in 28 patients with PD and motor complications submitted to pallidotomy and followed by one year (n = 28) and 2 years (n = 12). RESULTS: The total motor score (Unified Parkinson's Disease Rating Scale [UPDRS]) in the off state improved by 33 and 23% at one and two years, respectively (p < 0.01). All the cardinal signs of the disease were significantly improved (p < 0.01): tremor (92%), rigidity (67%), bradykinesia (46%) and axial symptoms (21%). A slight tendency to worsening in axial symptoms was observed. Dyskinesias disappeared in all but one patient. The Schawb & England Scale in off was improved by 21%. No improvement in the non-operated side was observed. The subgroup of patients with an improvement of less than 30% in the UPDRS was older than the one with larger clinical benefit. The observed tendency to worsening in the total motor score was related mainly to the progression of the symptoms in the non-operated side. Complications were mild and transient. CONCLUSIONS: Pallidotomy is a relatively safe and effective therapeutic option for complicated PD patients. An adequate selection of patients is necessary, since efficacy is partial and limited to one hemibody.

Adult↗
PubMed1999

[Pathophysiological bases, clinical results and indications for surgical treatment in Parkinson disease].

We review the present status of surgery for Parkinson's disease. Surgical options for Parkinson's disease are rapidly spanding. The main objectives of surgical techniques are to restore the dopaminergic deficit in the striatum (transplantation) and to normalize the neuronal activity of the subthalamic-pallidal circuit (pallidotomy and deep brain stimulation). Whereas cell transplantation is still considered an experimental procedure, ablative procedures and deep brain stimulation are widely used. Both types of surgical procedures are supported by strong scientific data. However, much work remains to be done in order to understand several aspects not clearly elucidated at present. The results and current indications for pallidotomy and deep brain stimulation are analyzed.

Brain↗