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Biomedical subjects

J M Delgado

Publications and source records attributed to J M Delgado.

At least 19 recordsLinked to original sources
PubMed1992

Cardiovascular reflexes in patients with malignant disease.

Although some authors have reported clinical features of autonomic dysfunction in patients with malignant disease only a few systematic studies have been carried out. We have investigated the autonomic function of 48 patients with carcinoma or lymphoma by testing their cardiovascular reflexes, and compared their results with those of 62 healthy volunteers. Our patients showed a smaller increase in heart rate and a greater fall in blood pressure on standing up, as well as a smaller rise in blood pressure in response to contralateral handgrip. The study group showed a higher percentage of established sympathetic lesion (54.2% vs 27.4%, p: 0.008) and of atypical pattern of global autonomic function impairment (50% vs 24.2%, p: 0.03) than the control group. Our data suggest that patients with malignant disease suffer from a definite autonomic dysfunction.

Aged↗
PubMed1990

Secretions of somatostatin and VIP in cultures of fetal rat neuroblasts increased by amino acids.

Neuroblasts obtained from 17 day old rat embryos were incubated for 8 days, after which half of them were treated with 10(-6) M FACE (a mixture of amino acids high in glycine, alanine and aspartic acid), and the other half were left as controls. At the end of 20 days, levels of somatostatin (SRIF) were over 6,000 pg/plate in neuroblasts treated with FACE, versus 500 pg/plate in controls. At this time vasoactive intestinal peptide (VIP) levels were over 230 pg/plate in the FACE treated cultures, while their controls contained less than 150 pp/plate. Protein totals were similar (about 1,000 micrograms/plate) in all FACE treated cultures and controls, indicating that increases in SRIF and VIP were not determined by changes in cell population, but by their synthetic and/or secretory activities triggered by minute amounts of FACE. These results may be of interest in the understanding of Alzheimer's disease.

Amino Acids↗
PubMed1990

Neurosecretory and trophic action on fetal rat neuroblasts induced by an amino acid mixture.

The effects of a synthetically obtained mixture of amino acids (FACE) were investigated on the trophic and neurosecretory activity of in vitro cultures of fetal rat neuronal cells. The addition of 10(-6) M FACE to the culture medium significantly increased cell DNA content. Secretions of IR-SRIF, IR-VIP, and IR-GRF were also augmented in different proportions by the presence of FACE. Time studies demonstrated that IR-SRIF was significantly increased after 48 (P less than 0.05) and 72 (P less than 0.01) hr of exposure to FACE, and IR-VIP secretion was potentiated after only 24 hr of culture. Dose-response experiments with 10(-7) to 10(-4) M FACE indicated that concentrations of 10(-5) and 10(-4) M significantly increased both somatostatin released to the medium and cell content of IR-SRIF. FACE concentrations as low as 10(-10) M augmented the secretion of IR-GRF, and there was a dose-response correlation between 10(-10) and 10(-5) M FACE. The release and cell content of IR-VIP were also increased by FACE, with a dose-response relation at concentrations of 10(-9) to 10(-6) M. It can thus be concluded that FACE has a powerful effect on the multiplication and survival of fetal cerebrocortical cells and is also an important potentiator of IR-SRIF, IR-VIP, and IR-GRF secretion.

Amino Acids↗
PubMed1979

Triunism: a transmaterial train--mind theory.

Triunism postulates that the mind is a unity with the following three structural elements so essential that the absence of any one will prevent its existence: (1) Brain cells and pathways possessing material and transmaterial properties. (2) A flow of environmental information, coded and transduced at the sensory receptors and forming part of the working brain through modifications of its anatomy and physiology. (3) Detectable manifestations derived from (1) and (2) which are expressed inward as perceptions and outward as behaviour. The outside world enters through the senses and becomes a material and functional part of the maturing brain. Without a brain, the mind cannot exist. Without sensory inputs, the mind will not be structured and cannot appear. Without manifestations of inner perceptions and outward motor expression, the mind cannot be recognized by the individual or the environment. Transmaterial entities require the existence of supporting matter and may be represented by patterns of material organization or by temporal or functional relations between parts of the material substratum. They may transcend the existence of specific materials, changing carriers while preserving their nonmaterial identity, but do not possess intrinsic properties of matter such as mass and energy. Transmaterial aspects of reality, including material substratum patterning, and relative temporal, and functional characteristics may be subjects of experimental research.

Animals↗
PubMed1979

Nocturnal and diurnal sleep in Macaca sylvana.

In Macaca sylvana restrained in chairs, continuous 24 h recordings were obtained of scalp EEG, neck EMG, bilateral EOG, motility of the head and lever manipulation. A total of 32 days were studied in 8 monkeys. Recordings were divided into epochs of 30 sec and analyzed in a PDP-12 computer. Four stages of sleep and 5 stages of wakefulness were identified by combination of the above data. Results were as follows: (1) During the night, there was 21% wakefulness and during the day 20% sleep, including a considerable amount of REM. (2) Recordings of spontaneous motility of head and hands proved an excellent indicator of sleep-wakefulness cycles. (3) Spectral analysis revealed the cyclic characteristics of non-REM sleep, with peaks at 360, 149, 72, and 55 min. (4) Stages of wakefulness had ultradian cycles, and stage W-2 was the most important in number and duration of occurrences. (5) Night wakefulness had characteristics different from day wakefulness. (6) Study of sequences showed that stage II was the least differentiated being transitional among the other stages, while stage III-IV was never preceded by wakefulness or REM, and almost always it followed stage II (99.0% of the time). (7) The high statistical significance of results obtained under restraint in different monkeys suggests that this situation has great potential value in the investigation of physiological mechanisms of ultradian rhythms.

Animals↗
PubMed1979

Optimization on the selection of auxotrophic mutants in Candida utilis by snail enzyme treatment.

The determination of the best conditions for the application of the snaill enzyme digestion method in the enrichment of auxotrophic mutants in Candida utilis was carried out following Box and Wilson's mathematical method. The selection procedure proposed was tested in the enrichment of auxotrophic mutants from a mutagenized culture of a wild-type strain. Mutant frequency was increased 46-fold by treatment with snail enzyme. The method also proved useful in the selection of additional auxotrophic mutations from single auxotrophs.

Amino Acids↗
PubMed1977

Cerebral blood flow and behavior during brain stimulation in the goat.

Cerebral blood flow, heart rate, arterial blood pressure, and behavior were studied in conscious goats during electrical stimulation of the diencephalon and mesencephalon. Stimulation of the subthalamic area produced a considerable increase in ipsilateral cerebral blood flow and heart rate, accompanied by either a small or a large increase in systemic arterial blood pressure. Cardiovascular effects were associated with changes in alertness. The increase in cerebral blood flow was partially abolished by previous administration of atropine directly into the internal maxillary artery. Stimulation of the mesencephalic reticular formation caused a marked increase in blood pressure with no change or with some decrease in cerebral blood flow. After administration of phentolamine into the internal maxillary artery, stimulation produced increase in cerebral blood flow. The behavioral response consisted of restlessness and attempted flight. These results suggest the existence of cholinergic vasodilator and adrenergic vasoconstrictor pathways to cerebral blood vessels that may be stimulated electrically.

Animals↗
PubMed1976

Neurobiology of aggressive behavior.

Causality, neurological mechanisms, and behavioral manifestations may be heterogeneous in different forms of aggressive behavior, but some elements are shared by all forms of violence, including the necessity of sensory inputs, the coding and decoding of information according to acquired frames of reference, and the activation of pre-established patterns of response. Understanding and prevention of violence requires a simultaneous study of its social, cultural, and economic aspects, at parity with an investigation of its neurological mechanisms. Part of the latter information may be obtained through animal experimentation, preferably in non-human primates. Feline predatory behavior has no equivalent in man, and therefore its hypothalamic representation probably does not exist in the human brain. Codes of information, frames of reference for sensory perception, axis to evaluate threats, and formulas for aggressive performance are not established genetically but must be learned individually. We are born with the capacity to learn aggressive behavior, but not with established patterns of violence. Mechanisms for fighting which are acquired by individual experience may be triggered in a similar way by sensory cues, volition, and by electrical stimulation of specific cerebral areas. In monkeys, aggressive responses may be modified by changing the hierarchical position of the stimulated animal, indicating the physiological quality of the neurological mechanisms electrically activated.

Acoustic Stimulation↗
PubMed1976

Ultradian rhythms in the mobility and behavior of rhesus monkeys.

The presence of ultradian rhythms in the mobility and behavior of rhesus monkeys was explored in eleven animals equipped with mobility FM transmitters and placed alone or in pairs in laboratory cage situated in a sound proof, temperature controlled room, with food and water ad libitum. After an habituation period of 3 to 7 days, telemetric recordings of the mobility of the animals showed ultradian rhythms with a periodicity of 70 min during the daily 12-h light period. During the corresponding 12-h dark period, there were two dominant cycles of 103-144 min and 48 min respectively. Restriction of food and water to 1h/day did not change the duration of these cycles, and the presence of random noise also had little effect. Spontaneous behavior occurred in regular sequences within each cycle. Social relationships were found to affect rhythmicity of behavior, since pairs of monkeys synchronized their cycles. The lever press response recorded during auto-shaping showed the same rhythmicity found in mobility, demonstrating the influence of ultradian rhythms on learned behavior.

Animals↗