Biomedical subjects

R Haro

Publications and source records attributed to R Haro.

9 recordsLinked to original sources

PubMed1995

EEG interhemispheric correlation after callosotomy: one case study.

High interhemispheric EEG correlation (INTERr) or coherence has been interpreted as a consequence of callosal interconnections. The EEG of a callosotomized (two anterior thirds) 32-yr.-old patient was recorded during relaxed wakefulness with eyes closed. 100 2-sec. artifact-free epochs were digitally filtered into traditional broad bands and INTERr was calculated by means of Pearson product-moment coefficients. INTERr between anterior regions, where they should be expected, showed very few differences between data of this patient and those of two control groups of healthy persons. Only a few differences were observed between posterior regions where the callosum was intact. These results suggest that the role of the callosum is not crucial for INTERr and that subcortical influences and functional differentiation between hemispheres may be more plausible explanations for INTERr.

Adult↗

PubMed1994

TRK2 is not a low-affinity potassium transporter in Saccharomyces cerevisiae.

TRK1 and TRK2 encode proteins involved in K+ uptake in Saccharomyces cerevisiae. A kinetic study of Rb+ influx in trk1 TRK2, trk1 TRK2D, and trk1 trk2 mutants reveals that TRK2 shows moderate affinity for Rb+. K(+)-starved trk1 delta TRK2 cells show a low-affinity component accounting for almost the total Vmax of the influx and a moderate-affinity component exhibiting a very low Vmax. Overexpression of TRK2 in trk1 delta TRK2D cells increases the Vmax of the moderate-affinity component, and this component disappears in trk1 delta trk2 delta cells. In contrast, the low-affinity component of Rb+ influx in trk1 delta TRK2 cells is not affected by mutations in TRK2. Consistent with the different levels of activity of the moderate-affinity Rb+ influx, trk1 delta TRK2 cells grow slowly in micromolar K+, trk1 delta TRK2D cells grow rapidly, and trk1 delta trk2 delta cells fail to grow. The existence of a unique K+ uptake system composed of several proteins is also discussed.

Azides↗

PubMed1993

Effects of ozone exposure during pregnancy on ontogeny of sleep in rats.

Few studies regarding the effects of ozone exposure in the central nervous system (CNS), during the early stages of development have been reported. The study of sleep on newborn rats represents a model to understand the effects of this gas on the CNS. We studied the sleep organization in rats whose mothers were exposed to 1 part per million (ppm) ozone during pregnancy. We found severe sleep disturbances such as a decrease in paradoxical sleep duration and inversion of the light-dark cycle or a circadian phase-shift of vigilance states. These results suggest that ozone exposure during pregnancy may affect the generating mechanisms of paradoxical sleep, and the regulation of circadian rhythms in rats.

Animals↗

PubMed1993

Differential expression of two genes encoding isoforms of the ATPase involved in sodium efflux in Saccharomyces cerevisiae.

The ENA2 gene encoding a P-type ATPase involved in Na+ and Li+ effluxes in Saccharomyces cerevisiae has been isolated. The putative protein encoded by ENA2 differs only in thirteen amino acids from the protein encoded by ENA1/PMR2. However, ENA2 has a very low level of expression and for this reason did not confer significant Li+ tolerance on a Li+ sensitive strain. ENA1 and ENA2 are the first two units of a tandem array of four highly homologous genes with probably homologous functions.

Adenosine Triphosphatases↗

PubMed1993

Multiple sleep latency test (MSLT) and sleep apnea in aged women.

Sleep disturbance and the tendency to sleep during the day were assessed polysomnographically in 31 elderly women (mean age = 76.7 +/- 3.6 SD) recruited from a senior citizen's living facility without reference to sleep-wake complaints. The data showed that the level of sleepiness during the day in each subject depended in part on the severity of her respiratory disturbance. It was found that the group (n = 7) of elderly females with apnea and hypopnea index (AHI) higher than 20 was more sleepy [multiple sleep latency test (MSLT) = 7.9 +/- 2) than the group (n = 10) with AHI > 5 but less than 20 (MSLT = 12.7 +/- 5). Nevertheless, the presence and severity of respiratory disturbance were not the only factors that influenced the level of sleepiness during the day in the studied sample. A subgroup of four elderly females showed a marked sleepiness during the four tested periods (MSLT = 5.2 +/- 0.6) with a very low respiratory disturbance index (AHI = 5.5 +/- 0.8).

Aged↗

PubMed1993

Obstructive sleep apnea secondary to surgery for velopharyngeal insufficiency.

The files of 585 patients who had had pharyngeal flap surgery for the correction of velopharyngeal insufficiency were reviewed. Eighteen patients, ranging in age from 6 to 16 years, showed clinical symptoms of obstructive sleep apnea syndrome. All of these cases had a polysomnographic evaluation and videonasopharyngoscopy. Fifteen cases met the criteria for the diagnosis of obstructive sleep apnea syndrome and eventually underwent surgical treatment. A modified uvulopalatopharyngoplasty was done in 14 of the 15 cases. One patient had a prominent uvula flipping into the port of a Jackson's type pharyngoplasty, so a partial resection of the uvula was performed. Surgical treatment was successful in 14 of 15 cases, including the case with the partial uvular resection. In one case, severe sleep apnea persisted after surgery and a complete section of the flap was performed to correct the obstruction. Sizeable tonsils were found in 13 out of 15 cases, whereas flap width appeared unrelated to obstruction. Preoperative assessment of tonsillar tissue is of vital importance before pharyngeal flap surgery.

Adolescent↗

PubMed1992

Activation of the potassium uptake system during fermentation in Saccharomyces cerevisiae.

Fermentable sugars activated the K+ uptake system, increasing the Vmaxs of Rb+, Na+, and Li+ influxes, but sugars did not affect the effluxes of these cations. This activation seems to be a direct effect of fermentation and not the consequence of the H+ pump ATPase activation or internal pH decrease produced by fermentation.

Adenosine Triphosphatases↗

PubMed1991

A novel P-type ATPase from yeast involved in sodium transport.

The gene ENA1 was cloned by its ability to complement the Li+ sensitivity of a low Li(+)-efflux strain. The nucleotide sequence of the cloned DNA fragment showed that there are two almost identical genes in tandem, and predicts that they encode P-ATPases. Disruption of both genes originated a strain defective in Na+ and Li+ effluxes, and sensitive to Na+, to Li+ and to alkaline pH. By transformation with ENA1 the defective effluxes and tolerances were repaired.

Biological Transport, Active↗

PubMed1990

Regulation of potassium fluxes in Saccharomyces cerevisiae.

To investigate the regulation of K+ fluxes in Saccharomyces cerevisiae the dependence of K+ efflux and Rb+ influx on [K+]i, pHi, [Na+]i, membrane potential, cell volume, and turgor pressure were studied in cells with different K+ contents. By decreasing the cell volume with osmotic shocks and the cellular pH with butyric acid the following was found. (1) The K+ efflux induced by uncouplers decreases simultaneously with the decrease of the K+ content of the cell, but the process was insensitive to [K+]i, pHi, cell volume and turgor pressure. The internal presence of Na+ inhibited this K+ efflux. (2) The increase of the Vmax of Rb+ influx observed in low-K+ cells is due to the decrease of the pHi and probably mediated by the increase of the activity of the plasma membrane ATPase. The Vmax is independent of [K+]i, [Na+]i, cell volume and turgor pressure. (3) The decrease in the Km of Bt+ influx observed in low-K+ cells does not depend directly on [K+]i, pHi, cell volume or turgor pressure. If Na+ is present, [Na+]i might be directly involved in the regulation of the Km.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗