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Biomedical subjects

J C Masdeu

Publications and source records attributed to J C Masdeu.

At least 19 recordsLinked to original sources
PubMed1992

Perception of different frequencies of cranial transcutaneous electrical nerve stimulation in normal and HIV-positive individuals.

Sine-wave transcutaneous electrical nerve stimulation (TENS) of varying frequencies applied across the cranium (ear to ear) has been demonstrated to evoke three different noncutaneous sensations in three discrete, nonoverlapping frequency bands in normal, healthy subjects. This report describes two studies which evaluate perception of these cranial TENS-evoked, frequency-dependent sensations in normal and HIV-positive individuals. In Exp. I, all of 50 normal, healthy subjects reported perceiving the same three noncutaneous sensations in the same three nonoverlapping frequency bands as long as stimulated and over repeated trials. In Exp. II, 34 HIV-positive individuals (14 asymptomatic, 9 ARC, 11 AIDS) who were free of neurological symptoms differed significantly from 10 normal, healthy controls, and from the norms observed in Exp. I, on perception of the three different TENS-evoked sensations. Also, inability to maintain perception of the stimulus over repeated trials, observed only in the HIV-positive individuals, increased significantly with severity of HIV infection.

AIDS Dementia Complex↗
PubMed1991

Interventions and functional brain imaging.

Assessment of regional cerebral blood flow (rCBF) is useful in the evaluation of cerebral vascular disease. However, a single resting study has limitations in that a normal rCBF may be present with diminished cerebral vascular flow reserve and regions of decreased rCBF may be seen with diaschisis or selective neuronal loss and an intact vascular supply. To help differentiate these conditions a stress rCBF study can be obtained following the administration of vasodilatory stimulus. The topic of this review is the discussion of single photon emission computed tomography (SPECT) and vascular intervention, primarily, acetazolamide (Diamox, Lederle Laboratory Division, Pearl River, NY) augmented SPECT in the evaluation of cerebral vascular disease.

Acetazolamide↗
PubMed1991

Extrapyramidal symptoms due to dopamine-blocking agents in patients with AIDS encephalopathy.

OBJECTIVE: The authors attempted to determine whether patients with AIDS are more susceptible to neuroleptic side effects than other patients. METHOD: Retrospective chart review was used to assess the frequency and severity of extrapyramidal symptoms in patients with AIDS and psychotic patients without AIDS who had taken dopamine-blocking agents. The charts of 804 men younger than 50 years were reviewed, and patients were excluded if they had not taken dopamine blockers, had taken them for more than 1 month, had received concomitant antiparkinsonian agents, had focal brain lesions or histories of Parkinson's disease or meningitis, had used cocaine, amphetamines, or opiates within 1 month of admission, or, among the comparison group, had HIV risk factors. For the remaining 31 AIDS and 32 comparison patients, age, duration of dopamine blocker treatment, dose in chlorpromazine equivalents, and nature and severity of parkinsonian complications were recorded. RESULTS: The mean drug dose and body weight were significantly lower in the AIDS group. The likelihood of developing extrapyramidal symptoms was 2.4 times as high among the AIDS patients as among the comparison group. Such symptoms were developed by 50% of the AIDS patients who received less than 4 mg/kg of chlorpromazine equivalents per day and 78% of those who received more than 4 mg/kg per day. CONCLUSIONS: These preliminary results suggest that AIDS patients are more susceptible to extrapyramidal symptoms than psychotic patients without AIDS and that neuroleptics should be used cautiously and in lower doses for patients with AIDS.

AIDS Dementia Complex↗
PubMed1991

Monocular elevation weakness and ptosis: an oculomotor fascicular syndrome?

The topographic arrangement of the fascicular portion of the oculomotor nerve in the midbrain is not known. A patient with infarction involving the lateral portion of the fascicle had isolated monocular elevation paresis and ptosis, suggesting that the fibers destined to the elevators of the eye and eyelid course laterally in the fascicle.

Aged↗
PubMed1991

Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: a preliminary report.

Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.

AIDS Dementia Complex↗
PubMed1990

Neurologic complications of cloacogenic carcinoma.

Cloacogenic carcinoma is a rare tumor, originating from epithelium of the anal transition zone. We report a 63-yr-old man with pathologically proven cloacogenic carcinoma which caused a rapidly progressive paraparesis and changes in mental status. These were related to extramedullary deposits around the spinal cord and cauda equina and intramedullary deposits in the brain. This pattern of neural involvement with anal canal carcinoma has not been reported previously.

Anus Neoplasms↗
PubMed1989

Chronic lymphocytic leukemia with hypothalamic invasion.

Headaches and a state of confusion developed in a patient with chronic lymphocytic leukemia (CLL). A computed tomography (CT) scan of the head showed a hyperdense lesion in the hypothalamus with obstruction of the foramina of Monro. Leukemic cells with monoclonal lambda B-cell markers were identified in the ventricular fluid at the time of surgical decompression. Similar cells were identified in the peripheral blood. This lesion has not been described as a complication of CLL, a disease that, unlike other leukemias, rarely has central nervous system manifestations.

Aged↗
PubMed1989

Brain white-matter changes in the elderly prone to falling.

Falls and impaired gait are a major source of morbidity in the elderly. Why some elderly become prone to falling is often unclear. We analyzed the gait, equilibrium, and brain computed tomography results of 40 elderly subjects without evidence of neurologic disease known to be associated with falls. Twenty of these subjects were prone to falling and the remaining 20 were nonfalling controls. These two groups were comparable in terms of age and sex (mean age, 83.3 years [SE, 1.7 years]). The group of fallers had significantly worse gait and equilibrium scores and a greater degree of white-matter hypodensity on computed tomography. White-matter hypodensity correlated with impaired gait and equilibrium scores but not with impaired performance on cognitive testing. This study reveals the association of white-matter disease with gait and balance impairment leading to falls in the elderly.

Accidental Falls↗
PubMed1988

Multifocal cytomegalovirus encephalitis in AIDS.

A 43-year-old man with the acquired immunodeficiency syndrome had clinical evidence of multifocal disease of the brain, but computed tomography was negative. Magnetic resonance imaging revealed multifocal lesions, histologically proven to be caused by cytomegalovirus. Therapy with 9[2-hydroxy-1-(hydroxymethyl) ethoxymethyl] guanine (BW B759U) resulted in stabilization of the patient's clinical disease and radiographic improvement of the lesions.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Thalamic astasia: inability to stand after unilateral thalamic lesions.

Inability to stand in the absence of motor weakness or marked sensory loss is usually considered to reflect midline cerebellar disease. However, the 15 patients reported here had astasia related to unilateral thalamic lesions, documented by autopsy and computed tomography in 2 patients and by computed tomography in 13. The lesions, including infarction (6), hemorrhage (7), and tumor (2), involved primarily the superoposterolateral portion of the thalamus, but spared the rubral region. Alert, with normal or near-normal strength on isometric muscle testing and a variable degree of sensory loss, the patients could not stand and 7 of them could not sit up unassisted. They fell backwards or toward the side contralateral to the lesion. They appeared to have a deficit of overlearned motor activity of an axial and postural nature. In the vascular cases, the deficit improved in a few days or weeks. However, these patients had a tendency to sustain falls during the rehabilitation period.

Aged↗
PubMed1988

Medullary satiety.

A 62-year-old man with a tegmental medullary glioma lost 30 pounds of weight in several months because of lack of appetite and early satiety. The medullary tegmentum may play an important role in regulating feeding behavior in humans.

Brain Neoplasms↗
PubMed1987

Midbrain-diencephalic horizontal gaze paresis.

Four patients with predominantly right-sided infarcts at the midbrain-diencephalic junction had an ipsilateral oculomotor palsy and contralateral gaze palsy. The gaze palsy to the left was supranuclear in nature, because the restriction of abduction was overcome by the oculocephalic reflex. However, it was masked on the right eye by the third nerve palsy. In all cases upgaze was impaired bilaterally, and infraduction was absent on the right. The restriction of abducting saccades remained for months, considerably longer than with supranuclear cortical lesions, suggesting that the damage extended beyond involvement of the frontopontine pathways. These cases represent clinical instances of a recently described experimental syndrome of impaired horizontal saccadic eye movements with lesions at the paramedian midbrain-diencephalic junction.

Cerebral Infarction↗
PubMed1986

Hemispheric white matter lesions in the elderly prone to falling.

Brain computed tomography studies of two groups of elderly (mean age 83.3 years, SE 1.7) with no neurologic diagnoses were compared. Sixteen of the subjects were non-fallers and the remaining 17 had frequent unexplained falls. The group of fallers had a significantly greater degree of white-matter hypodensity of the elderly (Student's t-test = 2.7, p less than 0.01).

Accidental Falls↗
PubMed1985

Incidence of seizures with phenytoin toxicity.

Among 50 patients with phenytoin intoxication, 14 had seizures during the episode. Seizures in 9 of these 14 patients probably resulted from poor seizure control despite high phenytoin levels, but in 5 cases, attacks were attributed to phenytoin toxicity. The only factor that seemed to correlate with seizures was a serum phenytoin level over 30 micrograms/ml. No demographic, metabolic, neuropsychiatric, or therapeutic variables were predictive; nor were any other symptoms of toxicity particularly likely to be found in association with seizures. Seizures are an occasional manifestation of phenytoin toxicity, particularly when levels are high.

Adult↗
PubMed1979

Spinal subarachnoid hematomas: clue to a source of bleeding in traumatic lumbar puncture.

Although damage to the veins of Batson's epidural plexus is usually considered the origin of bleeding in traumatic lumbar puncture, a lesion of these veins would not explain the cases in which postmortem examination shows blood confined to the subdural and subarachnoid spaces. In two patients who had lumbar punctures a few days before death, there was subarachnoid hematoma of the cauda equina at autopsy. In one of these cases, the radicular vessels were shown to be the source of bleeding. Spinal subarachnoid and subdural hemorrhages after lumbar puncture may be due to laceration of radicular vessels by the spinal needle.

Adult↗