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Biomedical subjects

A Esteban

Publications and source records attributed to A Esteban.

At least 109 records · Page 6Linked to original sources
PubMed1982

Pulsus paradoxus in acute myocardial infarction.

Sixteen patients, admitted no later than eight hours after the onset of the first stage of acute myocardial infarction, underwent systemic, pulmonary, and pulmonary wedge pressure measurements on admission and 24 and 48 hours after the first symptoms. A decrease in systolic blood pressure during inspiration equal to or greater than 15 mm Hg was found in 56 percent of the cases at admission, 53 percent at 24 hours, and 41 percent at 48 hours. No correlation could be found between this and: (1) pulmonary wedge pressure, (2) arteriovenous oxygen difference (volume percent), (3) location, and (4) extension of the necrosis. The last was indirectly assessed by the maximum levels of creatine phosphokinase attained. We discuss the previously postulated mechanisms causing pulsus paradoxus and formulate a theory to explain in acute uncomplicated myocardial infarction.

Blood Pressure↗
PubMed1981

Early detection of Huntington's disease. Blink reflex and levodopa load in presymptomatic and incipient subjects.

The R2 response on the blink reflex was found to be abnormal in seven out of 17 Huntington's disease descendants. Such abnormalities were present in four untreated subjects and in three further subjects after administration of a single oral dose of levodopa-carbidopa. An increase in latency and differential latency (four cases), or in a single one of these parameters (three cases) were the abnormalities found, resembling findings in four incipient cases detected during routine family surveys. Continuous administration of levodopa-carbidopa over a 10-20 day period did not induce new characteristics in the blink reflex, nor increase those detected previously, and no case developed chorea. We suggest that the analysis of the blink reflex after a single oral levodopa-carbidopa dosage could provide an objective and quantifiable method for the detection of individuals at risk for Huntington's disease.

Adolescent↗
PubMed1979

Reciprocal reflex activity in ocular muscles: implications in spontaneous blinking and Bell's phenomenon.

Levator palpebrae (m. lev. palp.) and rectus superior (m. rect. sup.) are two synergistic muscles in vertical gaze movements. However, they show an antagonistic behavior during electrically induced blink and glabellar reflexes. This can be considered as an easy and useful method for their differentiation in the electrophysiological study of certain oculopalpebral motor disorders. Blinking consists of a series of reflex activities, the most outstanding ones being an early m. lev. palp. basal activity inhibition, followed by the activation of the orbicularis oculi muscle and a brief increase in m. rect. sup. activity (reflex Bell phenomenon). This coordinated reflex organization could be perfectly related to that known in other human nociceptive reflexes.

Amyotrophic Lateral Sclerosis↗
PubMed1978

Abnormalities of Bell's phenomenon in amyotrophic lateral sclerosis: a clinical and electrophysiological evaluation.

A clinical and electromyographic study of oculomotor function was carried out in a series of 24 patients with amyotrophic lateral sclerosis (ALS). In 15 cases an alteration of Bell's phenomenon was found. In addition, three patients showed some impairment of conjugate ocular motility in the form of upward gaze paly. All cases had preserved oculocephalic reflexes in the vertical and horizontal planes. On clinical and electromyographic grounds, three degrees of altered Bell's phenomenon are suggested: attenuated (short and unsustained upward displacement of the eyeballs after forced closure of the eyelids), abolished (no upward displacement), and inverted (downward instead of upward displacement of the eyes). These oculomotor alterations were not directly related to the type of ALS at onset of the illness, nor with its duration. However they were correlated with the relative degree of the clinical bilateral pyramidal tract signs at the supraspinal level. The common involvement of the corticogeniculate tract in ALS could explain the unexpectedly high incidence of alteration of Bell's phenomenon found in this disease, but is is non-specific and similar lesions from different causes may also produce it.

Adult↗
PubMed1977

Prognosis in hereditary amyotrophic lateral sclerosis.

Two different forms of hereditary amyotrophic lateral sclerosis (ALS) has been separated according to duration of illness. A rapid course with short survival as seen in sporadic ALS is usual, but a comparatively benign type with a mean survival of 12 years has been reported in some families. Four patients from an ALS-afflicted family with five affected members in three generations were examined and then followed up. A conspicuous variability in progression among the patients was observed, with death occurring from 26 months to 12 years after onset; one patient is alive 13 years after onset. Wide differences were also found with respect to initial site of involvement and pyramidal tract signs. Three other families with this mixed pattern of prognosis have been reported previously. Affected individuals within involved families had either short or long duration of the disease, rather than displaying a continuum. However, in view of the existence of a type of hereditary ALS with marked intrafamilial variability, prognosis, even in the presence of previous benign cases, should be cautiously given.

Adult↗
PubMed1976

Regeneration of the spinal ventral roots. An experimental study in cats.

From a clinical standpoint recovery of spinal nerve roots is less likely than that of peripheral nerves, despite their identical structures. This may be due to several factors including the length of gap to be bridged, changes in the proximal stump or neuroma, and chromatolysis. In this paper we discuss the roles of some of these factors in relation to the neuronal depopulation in the spinal cord anterior horn area following section of the anterior root. The lack of growth or the successful growth of the axon through the gap in the root influences the degree of depopulation in the anterior horn area.

Animals↗
PubMed1976

Dystonia in Spain: study of a Gypsy family and general survey.

A girl from a Spanish Gypsy family developed idiopathic torsion dystonia when 12 years old. Parents were first cousins and both the pattern of clinical involvement and the rate of progression corresponded to that usually found in the autosomal recessive form of the disorder. Serum dopamin-beta-hydroxylase activity in the patient and close family members were also in keeping with this hereditary form. A nationwide inquiry failed to detect further cases of torsion dystonia among Gypsies, but revealed a relatively large number of recessively inherited disorders of the nervous system in this inbred, genetically isolated population. Thirty-six additional cases of torsion dystonia were collected from the general Spanish population, including four with a family history for this condition. The gene responsible for the recessive illness appears to be rare in many countries, explaining the sporadic nature of the disorder and its eventual appearance only in genetic isolates or after consanguineous matings.

Adolescent↗
PubMed1975

Blink reflex in Huntingon's chorea and Parkinson's disease.

The electrically-evoked late response (R2) of the blink reflex has been determined in 8 well-documented cases of Huntington's chorea and in 19 Parkinsonian patients. The results obtained from the two groups are compared with those from 10 normal subjects. A statistically significant difference of some components of the blink reflex was obtained when the three groups were compared. In both pathological conditions, the habituation index, latency and differential latency can be considered to represent the opposite extremes from the same scale, providing further evidence of the neurophysiological antagonism between the two disease states. The blink reflex pattern in Huntington's chorea probably reflects a diminished brain-stem interneurone basal activity through an over-inhibition of dopaminergic receptors in the striatum. The electrophysiological analysis of the blink reflex in incipient Huntington's chorea can provide an objective diagnostic assessment. It might be an effective method of detection for dopaminergic-activated carriers asking for genetic counseling.

Adult↗