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J M Delgado

Publications and source records attributed to J M Delgado.

At least 37 records · Page 2Linked to original sources
PubMed1989

Temporal profile of levels of monoamines and their metabolites in striata of rats implanted with dialysis tubes.

We have measured the levels of monoamines and their metabolites in rat striata implanted with a dialysis tube, in contralateral nonimplanted striata, and in dialysates obtained from the dialysis tube. The perfusion was done with Ringer solution. The animals were perfused either for a continuous period of 7 h at 1 day after implantation or for periods of 2 h on days 1, 4, and 7 after implantation. In animals perfused for 7 h, levels of monoamine metabolites in dialysates remained stable for the first 4 h of perfusion, but a reduction was observed during the last 3 h. In animals perfused for 2 h on days 1, 4, and 7 after implantation, we observed a progressive reduction in levels of metabolites in dialysates with respect to the first day of perfusion. The levels of dopamine and its metabolites in the striata in which a dialysis cannula had been implanted showed a progressive reduction during the period postimplantation comparable to that observed in dialysates. The levels of 3-methoxytyramine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were elevated 24 h after implantation in the implanted striata with respect to the contralateral nonimplanted striata, but 7 days after implantation, the levels of dopamine were decreased in the implanted striata, and the levels of metabolites were unchanged.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Care of the patient with Parkinson's disease: surgical and nursing interventions.

Parkinson's disease (PD), occurring in one million people with 50,000 new cases each year, is the most prevalent degenerative neurological disorder. With symptoms occurring insidiously and gradually, PD typically strikes in the sixth decade of life. Parkinsonian signs and symptoms include the classic combination of resting tremor, rigidity, bradykinesia and postural instability. The impact of the disease varies among individuals. Since the experiences of patients with Parkinson's disease are so varied and complex, nurses must play a pivotal role in their care. The quality of life of individuals with PD has changed dramatically since the advent of levodopa (L-Dopa) and other anti-Parkinson drugs. Recently autotransplantation of the adrenal medulla into the caudate nucleus, an investigational surgical treatment for Parkinson's disease, has been developed. Success with this procedure has been reported in two case studies. Autotransplantation is performed in several institutions in the United States. In this paper, the acute nursing care of individuals who have undergone autotransplantation, as well as short-term effects of the procedure on the lives of two patients and their families will be examined. This article addresses traditional medical treatment, physiology of movement and autotransplantation in addition to two case studies.

Adrenal Medulla↗
PubMed1985

Aminobutyric acid greatly increases the in vivo extracellular taurine in the rat hippocampus.

The effects of gamma-aminobutyric acid (GABA) on the extracellular levels of taurine and on excitability in the dentate gyrus were studied in anesthetized rats by the dialytrode technique. The dentate gyrus was perfused by means of a dialytrode with Krebs-Ringer-bicarbonate or GABA solutions. Amino acid contents in perfusates and dentate field potentials evoked by electrical stimulation of the perforant pathway were evaluated. GABA drastically elevated the levels of extracellular taurine in a dose-dependent manner, decreasing the amplitude of the population spike. This result indicates that GABA stimulates taurine release, probably by a counter-transport process. It is suggested that in physiological conditions an increase in extracellular taurine may be produced by synaptically released GABA.

Animals↗
PubMed1984

Dialytrode technology and local profiles of amino acids in the awake cat brain.

Methods to investigate the in vivo effects and release of neuroactive substances include cortical cups, push-pull cannulae, chemitrodes, and dialytrodes. Critical evaluation of these procedures is necessary in order to interpret related results and to select the most suitable devices for further studies. Recent improvements in the dialytrode include structural modifications and the use of a small, permeable membrane constructed of thin polyester. The dialytrode system and its diffusion rates have been characterized with in vitro studies. In vivo long-term experiments in awake cats have been conducted to test injection rates, diffusion of [14C]urea, temporal variability, pressure factors, and other experimental variables. Using dialytrodes we have measured the normal profile of amino acids present in different cerebral structures and their possible correlations.

Amino Acids↗
PubMed1983

Oviposition and development of Drosophila modified by magnetic fields.

Drosophila flies placed in a habitat with two lateral boxes demonstrated sensitivity to magnetic fields: Oviposition decreased by exposure to pulsated (extremely low frequency (ELF) (100 Hz, 1.76 miliTesla (mT) ) and sinusosidal fields (50 Hz, 1 mT), while there was no initial effect of exposure to a static magnetic field (4.5 mT). Drosophila eggs treated for 48 h with the above described fields showed that 1) mortality of eggs was lower in controls than in eggs exposed to all tested magnetic fields; 2) mortality of larvae increased when a permanent magnet was used; 3) mortality of pupae was highest when a permanent magnet was used; and 4) general adult viability was highest in controls (67%) and diminished progressively when eggs were exposed to pulsated (55%), sinusoidal (45%), and static (35%) magnetic fields.

Drosophila melanogaster↗
PubMed1983

Aspartate kinase and homoserine dehydrogenase of Candida utilis.

Aspartate kinase and homoserine dehydrogenase activity were assayed in a dialyzed cell-free extract of Candida utilis. Aspartate kinase was partly inhibited by ATP-Mg and by Mg2+ alone. There appear to be two isoenzymes of aspartate kinase in the yeast, one heat-labile, the other relatively heat-stable. The first is subject to feedback inhibition by threonine, the other is threonine-resistant. Neither aspartate kinase nor homoserine dehydrogenase is the rate-limiting enzyme in methionine biosynthesis. Homoserine dehydrogenase measured in the forward direction showed an activity five times higher than aspartate kinase. No regulatory interaction could be demonstrated for this enzyme. No repression of aspartate kinase and homoserine dehydrogenase synthesis by threonine, methionine or both amino acids was observed.

Adenosine Triphosphate↗
PubMed1983

Periaqueductal gray inhibition of trigeminal subnucleus caudalis unitary responses evoked by dentine and nonnoxious facial stimulation.

The possible pain inhibitory effects of periaqueductal gray (PAG) stimulation were investigated in cats anesthetized with Nembutal and immobilized with Flaxedil. Unitary responses evoked by electrical stimulation of the upper canine dentine and by cutaneous facial noxious and nonnoxious stimuli were recorded extracellularly from the trigeminal subnucleus caudalis. A bipolar electrode was introduced into the PAG to test the effects of PAG excitation on the trigeminal response to dentine (TRED) and cutaneous nonnoxious stimulation. In some experiments, a similar electrode was lowered into the contralateral posterior thalamus to study the antidromic activation of subnucleus caudalis cells and the effects of thalamic stimulation on the TRED. Dentine stimulation evoked brief (6- to 15-ms) bursts of 1 to 10 spikes with 3- to 25-ms latencies. Most units (88%) were also activated by cutaneous facial stimulation. Stimulation of the posterior thalamus had no effect on the TRED or on responses to cutaneous stimulation, but activated antidromically 10% of the units. In 71% of the units PAG stimulation inhibited the TRED. In some of those cases (12%), the inhibitory effect persisted 30- to 60 s. The PAG stimulation could produce paradoxical effects, potentiating the TRED evoked by threshold intensity and inhibiting the TRED elicited by suprathreshold stimulation. About one-half the PAG points evoked detectable effects. Their location had no clear topographical distribution, although ventral sites were more potent than dorsal sites. Responses evoked by nonnoxious facial stimulation were also inhibited by the PAG.

Animals↗
PubMed1983

Pulse shape of magnetic fields influences chick embryogenesis.

A total of 295 chick embryos was exposed during the first 48 hours of development to pulsed electromagnetic fields of 100 Hz and 0.4 to 104 microTeslas (micro T), and findings were compared with those in 364 control embryos. General morphology was analysed and supplemented by light microscopy studies. Exposure to electromagnetic fields with a pulse rise time of 100 microseconds produced teratogenic changes when intensities of 1.0 and 13.9 micro T were used but not with lower or higher intensities, demonstrating a 'window' effect and ruling out the possible influence of a rise in internal embryonic temperature. Exposure to an electromagnetic field of 1.0 micro T specifically altered organogenesis of the truncal nervous system and drastically reduced the alcian blue-stained components, whereas with an intensity of 13.9 micro T, there were abnormalities in the circulatory system and foregut, altering cell-to-cell contacts in the walls of developing vessels. When embryos were exposed to intensities of 0.4 and 1.0 micro T with 2.0 and 42 microseconds pulse rise times, teratogenic effects were greater and alterations involved all developing systems. The most powerful effects were obtained with 1.0 micro T and 42 microseconds rise time. The findings confirm the sensitivity of chick embryos to electromagnetic fields of extremely low frequency and intensity and indicate that pulse shape may be a decisive parameter determining strong, slight, or no modification of embryonic development. Mechanisms of action of electromagnetic fields are still unclear, but induced alterations in extracellular glycosaminoglycans could be a causal factor in the observed malformations.

Animals↗
PubMed1982

Embryological changes induced by weak, extremely low frequency electromagnetic fields.

Fertilized chicken eggs were incubated for 48 hours while exposed to extremely low frequency magnetic fields (ELMF) of 10 Hz, 100 Hz and 1000 Hz with intensities of 0.12, 1.2 and 12 micro T. Gross morphological and histological analysis of the exposed embryos revealed the following effects: (1) ELMF of 100 Hz/1.2 micro T had the most consistent and powerful inhibitory effect on embryogenesis. Development of embryos was reduced to the formation of the three primitive layers. Brain vesicles, auditory pit, neural tube, foregut, heart, vessels, and somites were not developed. Glycosaminoglycans were almost absent. (2) The above results demonstrate a window effect because embryos exposed to 100 Hz/1.2 micro T were less developed than embryos exposed at lower and higher intensities and frequencies. (3) Developing organs reacted with different sensitivity to ELMF of specific frequencies and intensities. Somites were not disturbed by exposure to 10 Hz with any of the intensities used. Formation of blood vessels was completely blocked by ELMF of 1000 Hz/12 micro T while traces of other organs were present. (4) The drastic embryological disturbances described were obtained with much lower intensities (1 micro T = 0.01 Gauss) than those used in studies by other investigators. (5) Embryological alterations induced by ELMF may depend on disturbances in the presence and structure of glycosaminoglycans which are essential elements in cellular activities, including cell migration. (6) The use of ELMF of low intensity may be a powerful method to investigate embryogenetic mechanisms and may also be a useful technique for investigation of other biological systems.

Animals↗
PubMed1981

Methionine-defective mutants in Candida utilis.

Ethionine-resistant mutants of Candida utilis CCY-158 overproducing methionine have been isolated. In these mutants the intracellular methionine concentration decreased significantly during the stationary phase. The wild-type strain CCY-158 and the ethionine-resistant mutants isolated were able to use methionine as the nitrogen source but not as the carbon source. From these ethionine-resistant mutants we isolated mutants unable to use methionine as nitrogen source (Mec- mutants), the principal alteration being at the level of methionine uptake. Some of the Mec mutants lost also the ability to use other amino acids as nitrogen source.

Candida↗
PubMed1981

Protoplast fusion in the yeast Candida utilis.

Protoplasts obtained by snail enzyme treatment from two stable auxotrophic mutants of the yeast Candida utilis were induced to fuse by the use of polyethylene glycol. The hybrids formed from the auxotrophic parental strains were selected by complementation on stabilized minimal medium. Many of the hybrids were unstable and readily dissociated into their parental strains. Others, in which parental nuclei had fused, gave stable hybrid progeny. cytological and genetic evidence of these processes is presented.

Candida↗
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↗