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M A Pastor

Publications and source records attributed to M A Pastor.

30 records · Page 2Linked to original sources
PubMed1992

Temporal discrimination is abnormal in Parkinson's disease.

Temporal discrimination thresholds (TDT) for recognition of paired sensory (tactile, auditory and visual) stimuli given over a wide range of time intervals were assessed in 44 patients with Parkinson's disease (PD) and 20 age-matched normal subjects. A significant increment in TDT for all three sensory modalities was found in PD patients compared with controls. This abnormality was greatly attenuated for about 2 h by a single levodopa/carbidopa (250/25 mg) tablet. A significant correlation was found between disease severity as assessed clinically and TDT. Patients with more severe PD had higher TDT values. The study of the peripheral median nerve and cortical somatosensory evoked potential recovery curves following double electrical stimulation of the index finger showed no differences between patients and control subjects, nor changes from 'off' to 'on' motor state which could explain the findings. These results indicate the existence of an abnormality of timing mechanisms in PD.

Action Potentials↗
PubMed1992

Time estimation and reproduction is abnormal in Parkinson's disease.

We compared the performance of 44 patients with Parkinson's disease (PD), tested 12-24 h after withdrawal of dopaminergic medication, with 20 age-matched controls, on a verbal test for time estimation and in several time reproduction tasks. Patients with PD underestimated the duration of a time interval in the verbal time estimation task and showed overproduction of time intervals when required to reproduce a short time sample. Absolute errors were greater in the reproduction of longer time intervals in both control and PD patients, but especially in the latter. The presentation of time markers at faster rates had a detrimental effect on the performance of the patients but not of the controls. Patients with more severe PD performed worse on the time estimation and reproduction tasks compared with those with milder disease. Administration of levodopa-carbidopa (205/25 mg, p.o.) significantly reduced absolute errors in time estimation and reproduction in conditions where time markers were presented at the two faster rates of 5 Hz and 3.3 Hz. Performance in these two latter tests best discriminated patients and controls and had a positive significant association with simple reaction time and movement time. These results lead us to suggest that time estimation, i.e. the 'internal clock', is abnormally slow in PD.

Adult↗
PubMed1992

Performance of repetitive wrist movements in Parkinson's disease.

The timing of repetitive alternating 80 degrees flexion-extension movements of the right wrist was studied in 42 patients with Parkinson's disease, tested while not receiving dompaminergic medication and 20 age- and sex-matched controls. Five rates of movement (0.5 Hz, 1 Hz, 1.5 Hz, 2 Hz, 2.5 Hz) were examined. The interval between two successive flexion movements, as measured from the electromyography (EMG) records was taken as the unit of analysis or inter-response interval (IRI). At 0.5 Hz, 1 Hz and 1.5 Hz there were no differences between groups in mean IRIs. At higher rates of movement (2 Hz and 2.5 Hz), however, the controls were significantly more accurate in timing of repetitive movements than the patients. At all five frequencies, the patients with moderate or severe Parkinson's disease were less accurate in timing of repetitive movements than those with mild disease, although the differences were not significant. In nine patients tested in the 'on' and 'off' medication states, administration of 250 mg of levodopa/carbidopa resulted in significantly more accurate timing of repetitive movements. Wing and Kristofferson's (1973b) two-process model of repetitive movements was applied to the IRI data. At various rates of movement, the primary prediction of the model that lag 1 autocorrelations should be in the 0 to -0.5 range was violated in 40-70% of the patient and controls. For those subjects who had lag 1 autocorrelations in the expected range, IRI variability was to break down into a timekeeper and a motor delay variance. At all frequencies, the patients had significantly higher variance for IRI, timekeeper and motor delay than the controls. Although not significant, more severe Parkinson's disease was associated with greater IRI, timekeeper and motor delay variance, while administration of levodopa resulted in reduction of the three types of variance. The validity of the Wing and Kristofferson model for the analysis of this type of movement is discussed.

Acoustic Stimulation↗
PubMed1991

The anatomical basis of somaesthetic temporal discrimination in humans.

Somaesthetic temporal discrimination (STD) is the ability to perceive as separate two successive somaesthetic stimuli applied to the same or different parts of the body. Paired electrical stimuli were applied to the index finger, using different time-intervals, to study the STD threshold (STDT) in 84 normal subjects and 51 patients with focal cerebral lesions. Abnormal STDT values were found on the affected side of patients with a lesion of the primary somatosensory cortex, and internal capsulethalamus. Lesions which did not produce sensory impairment but caused abnormal STDT were located in the posterior parietal cortex, the head of the caudate nucleus, the putamen, the medial thalamus and the lenticular nucleus. Frontal, temporal and occipital cortex lesions did not produce any abnormality in the STDT, but one patient with a bilateral lesion of the supplementary motor area (SMA) had abnormal STDT. These results indicate that normal perception of two somaesthetic stimuli as separate in time depends not only upon the integrity of the somatosensory pathway and primary somaesthetic cortex, but also of the posterior parietal cortex, SMA and subcortical structures such as the striatum and thalamus.

Adolescent↗
PubMed1985

Intra-arterial and intravenous chemotherapy for the treatment of malignant glioma. Preliminary results.

Twenty-one patients with malignant glioma were treated with cis-diamminedichloroplatinum II (CDDP II) 60-90 mg/m2 intra-arterial (I.A.) bolus on day 1 and Carmustine (BCNU) 100 mg/m2 intravenously (I.V.) on days 1 and 2. Three patients received additional Aziridinylbenzoquinone (AZQ) 7 mg/m2 (I.V.) on days 1 and 2. At the time of this treatment, seven patients had local recurrence after previous surgery and radiotherapy. Nine patients had subtotal tumor resection or biopsy, one patient had macroscopic tumor resection, and four patients had no previous surgery because of medical contraindication. Six patients received five or more courses of I.A. and I.V. chemotherapy. Five of these patients showed complete remission (CR) and one had a partial remission (PR) by brain computerized tomography (CT scan). Another 15 patients treated with two to four courses of I.A., and I.V. chemotherapy showed eight partial responses (PR), and seven showed no changes (NC) by brain CT scan. Five patients died with disease. Patients who achieved CR also received radical radiotherapy for remission consolidation. Sixteen patients are still alive; five patients are off treatment, four of these with no evidence of disease (NED), one alive with disease (AWD); and the remaining 11 patients are still on treatment. Toxicity, symptomatic neurological recovery, disease stabilization, and causes of death will be discussed.

Adult↗
PubMedDate not supplied

[Two HHV8-related illnesses in a HIV-negative patient: Kaposi's sarcoma and multicentric Castleman's disease. Response to treatment with Rituximab and CHOP].

Human herpes virus 8 (HHV8) was discovered in 1994 in the biopsy of a Kaposi's sarcoma in a patient with AIDS. Since then it has been identified in all variants of Kaposi's sarcoma and in another two rare disorders: multicentric Castleman's disease and primary body-cavity based lymphomas. The case discusses a 68 year old, HIV-negative male patient, presenting Kaposi's sarcoma for one year and being monitored by dermatology, who presented for weakness, anorexia and fever. On examination, he was found to have adenitis of the lymph nodes in his neck, underarm and groin. A biopsy on one of the swellings led to findings characteristic of multicentric plasma cell variant Castleman's disease. Blood tests for HHV8 and HIV were carried out, resulting positive and negative respectively (IgG anti-HHV8 positive, title 1/640, indirect immunofluorescence). PCR amplification showed HHV8 in peripheral blood. Patient received 8 cycles of CHOP and rituximab, leading to complete disappearance of the adenitis and general symptoms, with no worsening of his Kaposi's sarcoma. Patient remained in complete remission for 10 months after treatment. This paper discusses the case of a HIV-, HHV8+ patient, diagnosed with classic Kaposi's sarcoma, who developed multicentric plasma cell variant Castleman's disease. The coincidence of two or more HHV8-related illnesses in a HIV-negative patient has rarely been described in medical literature. Treatment with rituximab combined with CHOP chemotherapy was effective in this case, and no worsening of the patient's KS was observed.

Aged↗
PubMedDate not supplied

[The pathophysiological basis of dystonia].

OBJECTIVE: We review the mechanisms that may involved in the pathophysiology of dystonia. DEVELOPMENT: The role of basal ganglia, spinal and brainstem interneurons, and primary motor cortex in dystonia will be discussed. Abnormalities in the discharge pattern of internal pallidum or thalamus, secondary to basal ganglia disorders might be the cause of disbalance between excitatory and inhibitory mechanisms in motor cortex. Other factors such as excessive repetition of a movement or abnormal sensory afferent discharges may be participating in cortical reorganization. CONCLUSIONS: Overlapping of the cortical representation of dystonic muscles due to enlargement of cortical maps could explain overflow and co-contraction phenomena. The study of the exact role of these factors in each type of dystonia is a challenge for the future that opens the door for new therapeutic approaches.

Anti-Dyskinesia Agents↗
PubMedDate not supplied

[Treatment of supratentorial glioma with intracarotid cisplatin and intravenous carmustine].

We report the results of intracarotid (IC) cisplatinum and intravenous carmustine (BCNU) in 26 patients with supratentorial malignant glioma and recurrent low grade glioma. A response rate of 53.84% (95% confidence interval 33.3%-73.4%) was found. The median survival for the whole group was 11 months (range 3-70), with 35% of patients surviving for 2 years. At the present time, 5 patients are still alive, with a median follow up of 68 months (range 56-70). Neurological toxicity has been low and transient, being attributable to the technical degree of care in catheter positioning, cisplatin dosage and the technique of drug administration into the carotid artery.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

A triple autoimmune association.

We present a female patient affected by the triple association of rheumatoid arthritis, amyloidosis and Sicca Syndrome. The individual pathological features are well documented. We discussed the rarity of this presentation and some pecularities of the case such as the presence of a true Sicca Syndrome with lymphoid infiltration of the salivary glands to distinguish it from other amyloid patients with Sicca Syndrome due to the infiltration of exocrine gland by amyloid.

Amyloidosis↗