Search PubMed⌕ Search

Biomedical subjects

F Torres

Publications and source records attributed to F Torres.

At least 91 records · Page 5Linked to original sources
PubMed1991

Intraoperative monitoring of the facial nerve during decompressive surgery for hemifacial spasm.

In 11 consecutive patients, intraoperative electromyographic (EMG) recordings were made from the facial muscles during microvascular decompression for hemifacial spasm. In one patient, recordings could not be obtained for technical reasons, and two patients had no abnormality. In the remaining eight patients, the abnormal response resolved before decompression in two, resolved immediately at the time of decompression in five, and failed to resolve in one. All patients were relieved of their hemifacial spasm. In the five patients whose abnormalities resolved at the time of decompression, there was a precise intraoperative correlation between decompression of the nerve and disappearance of the abnormal EMG response. In three cases, this was a useful guide to the need to decompress more than one vessel. These results confirm the findings of Møller and Jannetta, support the use of this technique for intraoperative monitoring of facial nerve decompression procedures, and provide strong circumstantial evidence that vascular cross-compression is an important etiological factor in hemifacial spasm.

Electromyography↗
PubMed1990

The lateralization of language comprehension using event-related potentials.

Event-Related Potentials were recorded over occipital and parietal scalp from left- and right-handed adults presented with a language and a non-language visual stimulus using a divided field, "oddball" paradigm. The major finding of interest was that the P300 component was larger over the left than the right hemisphere of the right-handers when the language stimulus was presented to the left hemisphere; there were no hemispheric differences for the left-handers, regardless of field of presentation. These results are discussed in the context of developing noninvasive measures to lateralize language function.

Arousal↗
PubMed1990

Serial epilepsy caused by levodopa/carbidopa administration in two patients on hemodialysis.

Two patients with similar clinical features are presented: both patients had chronic renal failure, on hemodialysis for many years but recently begun on a high-flux dialyzer; both had been receiving a carbidopa/levodopa preparation; and both had the onset of hallucinosis and recurrent seizures, which were refractory to anticonvulsants. The first patient died without a diagnosis; the second patient had a dramatic recovery following the administration of vitamin B6. Neither patient was considered to have a renal state sufficiently severe enough to explain their presentation.

Aged↗
PubMed1988

Postprandial blood pressure changes during hemodialysis.

The effect of eating on BP during hemodialysis was examined in nine nondiabetic end-stage renal disease (ESRD) patients. A standard meal was given during 62 of 125 dialysis treatments in a prospectively controlled study. Diastolic (P = 0.01) and mean (P = 0.03) BPs fell significantly faster in the 45-minute postprandial period in the fed treatments compared with equivalent times in the fasting treatments. In this period, symptomatic hypotension occurred 13 times in five patients fed during dialysis compared with two episodes in one patient while fasting (P less than 0.05). Consumption of meals during hemodialysis should be avoided in patients at risk for hypotension during treatment.

Adult↗
PubMed1988

The effect of red cell transfusion on hemodialysis-related hypotension.

Blood pressures of 25 stable end-stage renal disease patients with chronic anemia (mean hemoglobin 5.9 g/dL) who had received 2 units of packed red cells during hemodialysis were studied. Three treatments preceding and three following the transfusion dialysis were compared. Twenty-eight hypotensive episodes preceded and 12 followed transfusion (P = .02). Intravenous sodium chloride used for hypotension declined from a mean of 20.4 to 10.2 mEq per dialysis (P = .01). The rate of decline in mean arterial pressure during dialysis was significantly slower following transfusion (P less than .01). Mean postdialysis weight fell from 62.0 kg before transfusion to 61.5 kg following transfusion (P less than .001). Thus, red cell transfusion raises intradialytic pressure and reduces the frequency of intradialytic hypotension.

Adult↗
PubMed1986

Electrophysiological correlates of a paroxysmal movement disorder.

Averaged electroencephalographic activity related to rhythmic jerking movements was recorded in a patient with a complex neurological symptomatology. The diagnosis of a functional disorder was strongly suggested by his clinical course, inconsistent findings from physical examination, and negative workup. His abnormal movements were associated with the same electrophysiological correlates as normal willed motion, suggesting that averaged movement potentials may provide useful information in the study of patients with suspected functional movement disorders.

Adult↗
PubMed1986

Androgen-binding proteins from human hyperplastic prostate as evaluated by electrophoresis.

Until 1972 it was shown that the androgen action in the prostatic tissue was through receptor proteins. In 1975 the synthesis of methyltrienolone (MT) opened a new field in searching receptor proteins. This synthetic androgen discriminates between receptors and other proteins such as TeBG and albumin. The main purpose in this investigation was to obtain the electrophoretic patterns of human prostatic androgen-binding proteins and compare them with those of other tissues from male genital tract (e.g., testes and epididymis), using as a reference the already described pattern in blood serum. The experimentation was carried out with cytosol (105,000 g) and nuclear fractions from the homogenized tissue. Both fractions were incubated with the tritiated steroids and then treated with dextran-coated charcoal. Polyacrylamide gel electrophoresis (PAGE) was then performed at pH 8.3 with acrylamide (T) 7.7%. The prostatic cytosol incubated with 3H-dihydrotestosterone (3H-DHT) revealed radioactive areas with the following average electrophoretic mobilities relative to Bromophenol Blue (Rf): 0.195, 0.285, 0.815, 0.910. When cytosol was incubated with 3H-MT the pattern showed radioactive peaks with Rf 0.280, 0.570, and 0.969. The nuclear fraction bound 3H-DHT in 0.190, 0.455, 0.570, 0.660, and 1.055 and bound 3H-MT in Rf 1.01. We concluded from these results that the electrophoretic patterns in the prostate gland shared some radioactive areas resembling TeBG and albumin, although they present low binding capacity. The other peaks with different electrophoretic mobilities are in the process of further identification.

Androgen-Binding Protein↗
PubMed1986

Clinical neurophysiology of dementia.

The role of EEG in the study of the dementias is to help in the differential diagnosis of the multiple causes of this syndrome. EEG is useful in differentiating early on between treatable and as of now untreatable forms of dementia. Space-occupying lesions that give rise to dementia are reliably detected by EEG. Infectious, toxic, and metabolic processes are associated with early and severe electroencephalographic abnormalities. The "slow virus" infections show characteristic electrical patterns that reliably distinguish them from the cortical or subcortical dementias. Finally, the EEG may contribute to distinguishing between Alzheimer's disease and MID, two commonly occurring forms of dementia. The paucity of substantial early EEG abnormalities in Alzheimer's disease, although helping to differentiate it from other dementias, leaves us without a currently available physiologic test that provides positive evidence for this condition. Recent studies of EPs, however, suggest that some intermediate latency VEP components may be delayed in patients with Alzheimer's disease when compared with normal subjects. This is encouraging, as latencies in VEPs are more reliable and less variable than amplitude that has previously been reported as "abnormal" in some early Alzheimer patients. Long latency ERPs and CNV also show early abnormalities in Alzheimer's disease. Tests of eye movements such as ERPs are psychophysiologic tests requiring some degree of patient cooperation. Performance on tests of ocular smooth pursuit correlate highly with severity of the dementia syndrome in Alzheimer's disease. In contrast, smooth pursuit testing is usually normal in elderly patients with pseudodementia of depression, suggesting this test may be of some value in differentiating these two clinical disorders. Some evidence exists that smooth pursuit eye movements are also normal, at least in the early and middle stages, in Pick's disease, again suggesting that eye movement testing may prove to have some utility in differentiating this form of dementia from Alzheimer's disease. Ocular scanpaths are abnormal in dementia. They typically are poorly organized and at times perseveratory. In addition, the average durations of eye fixations during directed visual search are altered in dementia as compared with normals. The average eye fixation durations are longer with Alzheimer's disease and briefer in patients with frontal lobe tumors as compared with elderly normal controls. These group differences suggest differing scanning strategies for these two forms of dementia.(ABSTRACT TRUNCATED AT 400 WORDS)

Alzheimer Disease↗
PubMed1985

The EEG of the early premature.

EEGs were taken of 33 premature babies of 27-32 weeks of conceptional age who were considered normal for their conceptional age by clinical criteria. The EEGs were divided into epochs of 1 min each and their characteristics of temporal and spatial organization as well as amount and distribution of special patterns were coded and analyzed. The records were mostly discontinuous, with synchronous and symmetric bursts. There was much rhythmic activity in all frequencies and some patterns were consistently asymmetric. At least one pattern, the sawtooth, seems to be characteristic of this early conceptional age. Follow-up EEGs and clinical examinations were done on 17 children at 6-8 months of age post term. Three more died before 6 months and on one a telephone report was obtained from the mother. The characteristics of the neonatal EEGs were compared with those published on smaller groups of early prematures and those on later premature babies.

Brain↗
PubMed1985

The normal EEG of the human newborn.

In the early premature, the EEG is mostly discontinuous. Discontinuity becomes limited to quiet sleep periods by the 36th week of conceptional age (CA). Temporal theta bursts, or the "sawtooth" pattern, come and go between 27 and 32 weeks' CA. Delta brushes attain their maximum about 32 to 34 weeks' CA and disappear about 40 to 44 weeks' CA. Frontal sharp transients have their peak occurrence at 35 or 36 weeks' CA and are still present at 44 to 48 weeks' CA. The background activity is essentially symmetric but transient patterns are less symmetric and frequently asynchronous. Lack of variability in the record is abnormal after 34 weeks' CA. Responses to isolated light flashes are prominent from very early prematurity through full-term. On the other hand, photic driving is frequent in early prematures (29-32 weeks' CA), but it then declines and is difficult to detect in the full-term neonate. Nonspecific responses to stimulation occur from early prematurity. Sleep--waking cycles are clearly discernible about 37 weeks' CA. Active sleep (rapid eye movement) goes from 60% at 34 weeks' CA to the 25% of adulthood at about 8 months of age. The EEG of the full-term newborn has four patterns, corresponding to three states: the low voltage irregular for wakefulness, high voltage slow and tracé alternant for quiet sleep, and the mixed for either wakefulness or active sleep.

Cerebral Cortex↗
PubMed1985

Cerebral dysfunction after chronic hypoxia in children.

Although the long-term effects of acute anoxia have been studied, the effects of chronic hypoxia on the developing human brain have received little attention. We studied children with a cyanotic congenital heart defect to assess the impact of chronic hypoxia by eight measures: neurologic examination, visual evoked response, EEG, behavioral adjustment, cognitive, perceptual-motor, and attentional functioning, and school performance. On outcome evaluation, these children evidenced diverse neurophysiologic dysfunction. Chronic hypoxia was associated with impaired motor function, inability to sustain attention, and low academic achievement.

Brain Diseases↗
PubMed1984

Critical frequency of photic driving in the diagnosis of multiple sclerosis.

Pattern visual evoked response (PVER) and critical frequency of photic driving (CFPD) to repetitive flash stimuli were studied in 68 consecutive patients suspected of multiple sclerosis (MS) and 15 normal controls to assess the diagnostic value of combined PVER-CFPD testing. Clinically, 38 qualified for the diagnosis of MS while 30 did not. The CFPD was found to be unreliable for detecting optic nerve dysfunction (OND) in MS, since well-defined photic driving at all frequencies above 40 flashes per second was not present in 14 patients without MS (47%) and in three normal control subjects (20%). The PVER, on the other hand, was highly sensitive and specific for OND, being abnormal in 12 patients with definite MS (92%) but in none of the normal controls. It is concluded that PVER by itself is a valuable test for the diagnosis of OND in MS and additional CFPD testing is uninformative and may even be misleading.

Adolescent↗
PubMed1984

Photic driving in the early premature infant.

Thirty-two infants born at gestational ages of 27-32 weeks were subjected to isolated flashes and intermittent photic stimulation. Their gestational age (GA) was assessed by maternal dates, physical examination and, when possible, examination of lens vasculature. The babies were selected for being of less than 33 weeks GA and being normal for GA on examination. Responses to isolated flashes were present in 63% and photic driving at 2-10 f/sec was present in 66% of the babies. Apparent discrepancies of these findings with previous reports about photic driving in prematures are discussed.

Electroencephalography↗
PubMed1983

The electroencephalogram of elderly subjects revisited.

The EEGs of 98 elderly volunteers were compared with those of 84 patients with a recent cerebral infarction who had achieved a stable clinical course. All subjects were uniformly evaluated according to a special protocol. The elderly volunteers were accepted for the study if they had no history, signs or symptoms of central nervous system disease. The EEGs were found to be significantly different between the two groups of subjects in several aspects. These included not only possible abnormalities, focal or diffuse, but also some normal features, such as alpha frequency and responses to photic stimulation and to hyperventilation. Groups of these differentiating features were analyzed. Using the single variable of ER (evoked response), discrimination of 80% was achieved. The variables that distinguish the volunteers from the patients may be used in the future to determine whether they are helpful in differentiating normals from patients with conditions other than stroke.

Aged↗
PubMed1983

Later competence and adaptation in infants who survive severe heart defects.

A model of risk potential for developmental outcome was created based on cardiac, medical, surgical, and family-stress factors in 31 children with transposition of the great arteries who had undergone reparative open heart surgery utilizing cardiopulmonary bypass during infancy. Impact of these potential risk factors was assessed by 4 current neurologic measures (neurologic anatomic abnormalities, functional impairment, electroencephalograph [EEG], and Pattern Visual Evoked Potential [PVEP]) and 4 psychologic measures (IQ, achievement, perceptual-motor function, and behavior). Results indicated that adverse developmental outcome was significantly associated with the following medical risk variables: failure of palliative surgery to alleviate hypoxia, prolonged hypoxia, growth failure, congestive heart failure, absence of ameliorating shunting heart defects, stroke, and CNS infection; and two psychosocial moderator variables: socioeconomic status and current life stress. Analysis of a "cumulative risk score" indicated significantly higher risk scores in children with abnormal EEGs, PVEPs, and neurologic examinations. The cumulative risk score highly correlated with composite neurologic outcome (r = .62), IQ (r = -.66), achievement (r = -.60), and perceptual-motor function (r = -.48). While overall outcome was favorable for children with TGA who experienced a single risk event, outcome was compromised if multiple risk factors occurred.

Achievement↗
PubMed1982

Hemiplegic migraine in childhood: diagnostic and therapeutic aspects.

Focal neurologic deficits, particularly hemiplegia, are occasionally observed in the pediatric migrainous population during the headache attack and are often mistaken for other neurologic or neurosurgical conditions. Clues to the correct diagnosis, illustrated by three patients in this report are: (1) rapid spontaneous recovery from the acute neurologic deficit, (2) striking electroencephalographic abnormalities, frequently consisting of focal slow waves during the acute stage, with rapid resolution, (3) significant past history of recurrent episodes, and (4) positive family history of migraine. Review of previously reported cases indicates that cerebral arteriography in the acute stage should be avoided if the clinical syndrome is typical. Preliminary results of prophylactic treatment with propranolol are encouraging; smaller dosage than those previously recommended sometimes can be effective.

Adolescent↗