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Biomedical subjects

P Roldan

Publications and source records attributed to P Roldan.

12 recordsLinked to original sources
PubMed2002

[Idiopathic granulomatous hypophysitis. Morphological and immunohistochemical study of a case].

Inflammatory diseases of the pituitary gland constitute a group of interest because of their scarce frequency, because the disorder presents with symptoms of hypopituitarism and expanding sellar mass and because of their therapeutics implications. We present one case of idiopathic granulomatous hypophysitis, in a 55-years-old patient with daily headaches, panhypopituitarism and a sellar mass lesion. Granulomatous hypophysitis is characterized by granulomas with epithelioid histiocytes and multinucleated giant cells but also shows lymphocyte collections. With respect to immunohistochemistry our results show histiocytes (CD68+) and an heterogeneous inflammatory infiltrate (CD45RO+ y CD20+). We analyze the differential diagnosis with another granulomatous processes, infectious or not infectious, and with the histiocytosis. We examine the possible relation with the lymphocytic hypophysitis.

Anti-Inflammatory Agents↗
PubMed1999

Interactive image-guided surgery system with high-performance computing capabilities on low-cost workstations: a prototype.

We present a new frameless stereotatic system prototype that has been initially validated in functional neurosurgery operations and that makes use of an optical position tracker for image-guided neurosurgery. Several devices for tracking different surgical instruments have been designed and manufactured. These devices include an array of infrared light-emitting diodes that are tracked by three charge-coupled device cameras. The system presents several new approaches for surgery planning. For high-quality 3D images of the patient's anatomy, we have developed a parallel version of a volume-rendering algorithm, thus enabling real-time 3D anatomy manipulation on low-cost PC workstations. In order to test the accuracy of the system, the localization of the target by means of a stereotatic frame has been compared with frameless techniques, obtaining a difference of about 1 +/- 1 mm.

Algorithms↗
PubMed1999

Electrical inhibition of basal ganglia nuclei in Parkinson's disease: long-term results.

Since 1995 a group of 57 patients with familial tremor and Parkinson's disease have been operated in two main sets: the first, with 11 cases, with predominant tremor, where the ventro-oralis posterior (Vop) thalamic nucleus was stimulated, and the second, with 44 cases, with mainly rigidity and akinesia, where the globus pallidus internus (GPi) was unilaterally (10 cases) or bilaterally (34 cases) stimulated. In 2 cases, a combined thalamic-pallidal stimulation was achieved. In the last cases, an image fusion software with 3D correlation of MR and CT images and volumetric image matching has been used to correct MRI distortion. In all cases, an Itrell II stimulation system (Medtronic) was implanted. Result analysis shows that Vop stimulation is mostly effective for tremor, and GPi stimulation is better for rigidity and akinesia. Transcortical magnetic stimulation tests suggest that GPi pallidal electrical inhibition increases cortical excitability, as opposed to Vop thalamic stimulation, which implies a different mechanism of action.

Adult↗
PubMed1987

Long-term results of percutaneous gasserian ganglion lesions.

Percutaneous radiofrequency lesion of the Gasserian ganglion was performed between 1974 and 1984 in ninety-eight patients for the relief of trigeminal neuralgia. The average follow-up period was 4.5 years. Age, sex, and duration of illness were unrelated to outcome. Satisfactory analgesia was achieved in 68 patients. Thirty-one percent had return of pain (30 cases). Recurrent neuralgia occurred most frequently during first postoperative year (46%). Patients with marked sensory deficits had a reduced risk of recurrence. Postoperative complications included: reduced or absent corneal reflex (18 cases), corneal keratitis (3 cases) and anesthesia dolorosa (2 cases).

Adult↗
PubMed1987

Radiosurgery of central pain.

Based on experimental and clinical evidence of central pain produced by hyperactivity of deafferented neurones and associated with irritative foci at thalamic or cortical levels, stereotactic low-dose (10 Gy) radiosurgery has been performed in 3 patients with central pain syndromes. SEEG findings and results of stereotactic radiosurgery on painful conditions are presented and mechanisms of action discussed.

Brain↗
PubMed1987

Hemodynamic changes from spinal cord stimulation for vascular pain.

The hemodynamic changes induced by spinal cord stimulation (SCS) have been studied in a group of 20 patients with peripheral vascular pain. The surgical technique consisted of the introduction of 1 or 2 electrodes in the subarachnoid space up to the level of the painful area, for mono or bipolar SCS. Several techniques have been used for evaluation of hemodynamic changes induced by SCS. Peripheral blood flow speed was measured by means of ultrasound Doppler, showing a raised maximum speed during stimulation, and a tendency of the pulse wave to return to normal. Thermography showed a marked increase of temperature in the painful area. Preoperatively, plethysmography showed an absence of the typical flow waveform, whilst postoperative recordings showed a small wave of progressively increasing amplitude. Scintigraphy with 201TI showed an increase in muscular blood flow in previously hypovascularized areas. The mechanism of action of SCS on peripheral blood flow and vascular pain is discussed.

Blood Flow Velocity↗
PubMed1985

Radiosurgical treatment of epilepsy.

Focal irradiation of epileptic foci has been performed in a group of 6 epileptic patients, of whom 2 presented with epilepsy and 4 with epileptic psychoses. The epileptic focus was localized by means of conventional scalp EEG, electrocorticography and stereoelectroencephalography. Radiosurgery was performed by coupling a stereoguide to a 60Co unit using a 10-mm diameter collimator. An estimated dose of 10 Gy was administered. Results are presented and the mechanism of action of radiation discussed.

Adolescent↗
PubMed1980

Burr-hole electrocorticography.

In 17 epileptic patients, most of them with seizures of partial type but with diffuse or focal alternating abnormalities in the electroencephalographic recordings, chronic implantation of subarachnoid electrodes was performed. Through two bicoronal burr-holes and under fluoroscopic control, 13 to 19 insulated monopolar flexible electrodes were introduced in the subarachnoid space, conducting them either to standardized cortical targets, or concentrating them in that area of interest showed by conventional EEG. The electrodes were placed bilaterally and symmetrically, and remained implanted for 10 days. During this period, the activity of multiple foci, the reciprocal dependence between them, its reaction to cortical electric stimulation, barbiturate administration and sleep, were studied. No morbidity was found. Because of the simplicity and safety of this technique, it appears to be a good diagnostic method placed between conventional EEG and stereoelectroencephalography.

Electric Stimulation↗