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Biomedical subjects

J Ramos

Publications and source records attributed to J Ramos.

At least 145 records · Page 8Linked to original sources
PubMed1991

[Spectrum analysis of the variability of heart rate in athletes].

OBJECTIVES: Characterize power spectrum pattern of the heart rate variability and assessment of the relative contributions of sympathetic and parasympathetic cardiac nervous system control in athletes. STUDY DESIGN: Prospective study of athletes and sedentary healthy control group sex and age matched. SUBJECT AND METHODS: 8 athletes, 3 female and 5 male, swimming (4), canoeing (2) and cycling (2), aged 17.4 +/- 3.6 years, and 8 sedentary healthy controls. ECG signals were recorded after a period of 15 minutes in supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive heart beats, we calculated the average, the standard deviation, the maximum and the minimum values and the rate between the longest and the shortest R-R interval (E/I). We also calculated, after computing the fast Fourier transform, the total spectrum power, the low frequency component (LF, from 0.01 to 0.15 Hz) and the high frequency component (HF, greater than 0.15 Hz) and its ratio (LF/HF). RESULTS: The average R-R interval was 921 +/- 154.2 msecs and 673.2 +/- 98 msecs, the standard deviation was 72.5 and 29.4 msecs and the ratio E/I 1.63 +/- 0.14 and 1.28 +/- 0.08, respectively for athletes and control group. Differences between groups were significant (p less than 0.01) for all parameters, with higher variability in the athletes. Both spectral bands (LF and HF) and higher power in athletes (LF = 0.54 +/- 0.23 and HF = 0.76 +/- 0.14) than in the control group (LF = 0.14 +/- 0.10 and HF = 0.18 +/- 0.15) (p less than 0.001). There were no significant differences for LF/HF ratio, or normalized LF (LF%) or normalized HF (HF%) between groups. CONCLUSIONS: The present results indicates higher power of both spectral bands (LF and HF) and higher amplitude of the respective peaks in athletes when compared with healthy sedentary, with a clear predominance of the HF band in the total spectral power density, which suggest that the higher heart rate variability observed in athletes reveals the predominance of parasympathetic activity, without reduction of the sympathetic tone.

Adolescent↗
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↗
PubMed1990

[Extracorporeal biliary lithotripsy: results in 60 cases of single calculus].

The outcome of 60 cases of single biliary stone with a maximum diameter of 25 mm was evaluated. The patients were symptomatic, with functioning gallbladder, and were selected from a group of 180 to evaluate the effects of electrohydraulically generated shockwaves on a priori ideal cases for this procedure. In seven patients fragmentation was not achieved, probably because of the pigmentary character of the stone, that was later verified at cholecystectomy. In 20 out of the 53 in whom fragmentation was satisfactory (38%), fragments were not observed after 24 hours. 32 patients (54%) had a stone-free gallbladder 3 months afterwards; at six months, the number had increased to 40 (66%). This rate becomes 77% if only the cases with fragmentation are considered. In 29% of patients episodes of colicky biliary pain developed as complication. No case of pancreatitis or stuck in gallstone were observed. We conclude that shock waves appear as an excellent therapeutic alternative in single gallstones up to 25 mm in size.

Adult↗
PubMed1990

Priapism and Fabry disease: a case report.

A 10-year-old boy presented with priapism of 10 h duration which after unsuccessful conservative measures, was relieved by a saphenocorporeal shunt. A 4-year history of intermittent vague aching of fingers and toes accompanied by low-grade fever was reported. Fabry disease was confirmed by the lack alpha-galactosidase activity in serum and leucocytes. Other characteristic features of Fabry disease were not present. The condition was also diagnosed in his 14-year-old brother and suspected in his maternal grandfather who died at the age of 49 from renal failure of unknown aetiology.

Child↗
PubMed1990

Transcutaneous electrical nerve stimulation (TENS) for the treatment of primary dysmenorrhea: a randomized crossover comparison with placebo TENS and ibuprofen.

In a randomized four-way crossover study, 32 women with primary dysmenorrhea were treated with transcutaneous electrical nerve stimulation (TENS) for two cycles, placebo (sham) TENS for one cycle, or ibuprofen 400 mg four times a day for one cycle. The TENS setting used was 100 pulses per second with 100-microsecond pulse widths. The subjects were allowed to adjust the amplitude to a comfortable level. The pain rescue medication was ibuprofen 400 mg as needed, up to 1600 mg/day. Significantly more subjects who had TENS treatment did not require rescue medication or required less backup ibuprofen at 0-4, 4-8, and 8-12 hours after the onset of dysmenorrhea and starting treatment, as well as during the first 24 hours and for the duration of the menstrual flow, when compared with placebo TENS or ibuprofen-treated cycles (Tukey multiple comparison, P less than .01). Transcutaneous electrical nerve stimulation significantly delayed the need for ibuprofen by an average of 5.9 hours, compared with 0.7 hours when using ibuprofen alone (P less than .05, paired t test). Transcutaneous electrical nerve stimulation alone provided good to excellent subjective pain relief in 42.4% of subjects, compared with 3.2% with placebo TENS, and significantly reduced diarrhea, menstrual flow, clot formation, and fatigue compared with placebo TENS. Transcutaneous electrical nerve stimulation plus less ibuprofen provided pain relief equivalent to that obtained with ibuprofen alone (71 and 75% of the subjects, respectively). We conclude that TENS is a safe, effective, non-medication method for managing primary dysmenorrhea and that TENS plus ibuprofen was the best overall treatment, as indicated by pain relief.

Adult↗
PubMed1990

The supraoptic nucleus: a morphological and quantitative study in control and hypophysectomised rats.

Several quantitative and morphometric parameters were analysed in the pars principalis of the supraoptic nucleus (SON) of the hypothalamus in control and hypophysectomised rats at several postnatal ages. The cell number in the control group remained approximately constant from Day 1, when it was 5034 +/- 348 (mean +/- S.D.M.), until Day 90 when the number of cells was 5234 +/- 110. In the group that was hypophysectomised on Day 60, the number of neurons on Day 90 was 1366 +/- 131, which represents a loss of 74% of the neurons. Morphometric parameters on Day 90 indicated a significant difference in nuclear size, 52.1 +/- 6.7 microns 2 in controls and 57.3 +/- 6.8 microns 2 in the hypophysectomised group. Based on these results, it is concluded that there is no postnatal loss of neurons in the pars principalis of the SON in normal rats. As a consequence of the stress induced by hypophysectomy, the remaining cell population undergoes adaptive changes in the nuclear RNA synthesis machinery of neurohypophyseal hormone precursors in order to compensate for the reduction in the number of neurosecretory neurons.

Age Factors↗
PubMed1989

[Dysplastic nevus syndrome with familial melanoma (type D2)].

A 37 year-old woman presented with type D2 familial dysplastic nevus syndrome with melanoma. A melanoma was excised of her back and more than one hundred pigmented lesions, four of which presented histologic characteristics of dysplastic nevus were observed. Several relatives of her presented multiple nevi and a sister of her mother and a brother of the patient had been diagnosed of melanoma. It is well established that such kind of nevi are precursor for melanomas, particularly familial forms. The clinical identification of such lesions is very simple and facilitates the diagnosis and early treatment of melanoma.

Adult↗
PubMed1989

Regional distribution of glycoconjugates in normal, transitional and neoplastic human colonic mucosa. A histochemical study using lectins.

Regional distribution of glycoconjugates in normal and neoplastic colonic mucosa was studied by means of eight lectins: Dolichos biflorus (DBA), Glycine max (SBA), Triticum vulgare (WGA), Arachis hypogaea (PNA), Griffonia simplicifolia-I (GS-I), Canavalia ensiformis (Con A), Limax flavus (LFA), and Ulex europaeus-I (UEA-I). The lectin binding patterns were examined in 40 normal colonic mucosa (NM) (12 proximal (P) and 28 distal (D], 38 carcinomas (15 P and 23 D), and 31 transitional mucosa (TM) (9 P and 22 D). Sections of NM located 5 cm and 10 cm distant from the tumour and sections from the resection margins (more than 10 cm from the tumour) of the surgical specimens were also studied in 19 cases (6 P and 13 D). In NM, regional differences between the proximal and distal colon were detected with most lectins. DBA, SBA and LFA bound mainly to the goblet cell mucin of the distal colon, while GS-I and UEA-I labelling predominated in proximal colonic mucosa. The lectin reactivity in carcinomas was: DBA 26%, SBA 63%, PNA 95%, GS-I 66%, UEA-I 76%, WGA 100%, Con A 92% and LFA 42%. No regional differences were observed in the lectin patterns of proximal and distal colonic carcinomas nor was any relationship detected between lectin reactivities and Dukes stage, size or histological type of tumours. Transitional mucosa of both the proximal and distal colon showed an increase in PNA-binding and loss of DBA and SBA. LFA and UEA-I reactivity in proximal TM was similar to that observed in proximal NM. Distal TM showed a decrease in LFA labelling and the appearance of UEA-I reactivity in goblet cell mucin in 5 cases (23%). The reactivity of the other lectins was as with NM. The only change in normal mucosa distant from tumours was a focal increase in PNA reactivity in 4 cases. These findings suggest that carcinomas from different colonic regions have a more uniform distribution of carbohydrates than the respective NM.

Colon↗
PubMed1989

Effect of normal sleep and sleep deprivation on interhemispheric correlation during subsequent wakefulness in man.

EEG activity was recorded from the right and left central, temporal, parietal and occipital derivations in 10 volunteers under the following conditions: at night before going to sleep, at night before sleep deprivation, in the morning after waking, in the morning after sleep deprivation and in the morning 48 h after recovery. Interhemispheric correlation and relative power were calculated for EEG samples of 20.48 sec. In the morning after normal sleep interhemispheric correlations were higher in all derivations in comparison to presleep values, while in the morning after sleep deprivation, interhemispheric correlations were lower or similar to predeprivation values in all derivations except the temporal cortex. The relative power of beta was significantly lower after normal sleep and higher after sleep loss, while the relative power of low frequencies was higher in the morning after sleep and lower in the morning after deprivation.

Adult↗
PubMed1989

Cortical and trabecular bone mineral content in women with endometriosis: effect of gonadotropin-releasing hormone agonist and danazol.

Cortical bone (distal radius and ulna) and trabecular bone mineral content of the thoracolumbar vertebrae (T-12 to L-4) were measured with single-photon absorptiometry and quantitative computed tomography, respectively, in 55 women with laparoscopically staged endometriosis before, during, and after treatment with a gonadotropin-releasing hormone agonist (GnRH-a) or danazol. Mean pretreatment potassium phosphate mineral contents of T-12 to L-4 were 174 to 201 mg/ml in stage I to IV endometriosis and were within the 100 to 115th percentile of normal women. Similarly, cortical bone mineral contents were normal and were not significantly affected by either medication. Trabecular bone decreased significantly to 92.6 +/- 1.7% (n = 11, P less than 0.001) and 92.3 +/- 2.5% (n = 7, P less than 0.01) of baseline year after 6 months and 9 months of GnRH-a treatment and remained significantly depressed at 95.8 +/- 1.9% (P less than 0.0025) and 94.8 +/- 2.5% (P less than 0.005) 6 months after stopping treatment. Thus, cortical and trabecular bone mineral contents of women with endometriosis are normal, but treatment with GnRH-a induced significant loss of trabecular bone.

Adult↗
PubMed1989

Evidence that temporary complete occlusion of splenic vessels prevents massive embolization and sudden death associated with intrasplenic hepatocellular transplantation.

It has been reported elsewhere that liver cell suspensions injected at several locations retain some proper hepatic functions, significantly improve the survival rate of rats with different models of acute fulminant hepatic injury, correct some congenital enzyme deficiency diseases, and improve liver function in cirrhotic animals. Among several locations, the splenic parenchyma has been shown to be the most suitable place for hepatocellular transplantation. Unfortunately, infusion of cells into the splenic pulp is not without risk. In fact, portal hypertension and hepatic embolizations have been described after intrasplenic transplantation of hepatocytes or pancreatic islets or fragments. In addition, pulmonary hepatocyte embolizations have been observed in rats with spontaneous (unpublished observations) or surgically induced portosystemic shunts. In this work, we evaluate the efficacy of temporary occlusion of splenic vessels to prevent hepatic and pulmonary embolizations after liver cell transplantation into the spleen in portal hypertension cirrhotic rats with portosystemic shunts.

Animals↗
PubMed1989

Characteristics of galactose transport in Saccharomyces cerevisiae cells and reconstituted lipid vesicles.

Growth on galactose induces two transport processes, a high-affinity and a low-affinity process. The most important results of a comparison of the two processes were that (i) both depended on GAL2 expression, (ii) only the high-affinity process required galactokinase, (iii) both were down-regulated by catabolite inactivation, (iv) neither was significantly inhibited by carbonyl cyanide-p-trifluoromethoxy-phenyl-hydrazone, (v) neither was differentially inhibited by silver nitrate or mercuric chloride, and (vi) transport activity with a Km closer to that of the low-affinity process of whole cells was reconstituted in fused phospholipid membrane vesicles.

Biological Transport↗
PubMed1989

Role of cyclic-AMP-dependent protein kinase in catabolite inactivation of the glucose and galactose transporters in Saccharomyces cerevisiae.

The derepressed high-affinity glucose transport system and the induced galactose transport system are catabolite inactivated when cells with these transport systems are incubated with glucose. The role of the cyclic AMP cascade in the catabolite inactivation of these transport systems was shown by using mutants affected in the activity of cyclic-AMP-dependent protein kinase (cAPK). In tpk1(w) mutants with reduced cAPK activity, the sugar transport systems were expressed but were not catabolite inactivated. In bcy1 mutants with unbridled cAPK activity resulting from a defective regulatory subunit, the transport systems were absent or present at low levels.

Biological Transport↗
PubMed1989

Does brain electrical activity react to music?

The electrical activity of the left and right central, temporal and parietal cortex was recorded in 14 amateurs of classical music during silence, pleasant (a piece of music) and unpleasant (a recording of an infant crying) stimulation. All the subjects rated the music as a pleasant stimulation and crying as an unpleasant one. Theta relative power was significantly higher while listening to music and lower during crying. Beta relative power did not change across conditions. No interhemispheric differences in the relative power were found. Interhemispheric correlation did not change either.

Adult↗
PubMed1988

Plasma and peritoneal fluid levels of CA 125 in women with endometriosis.

Determined by a sandwich, solid-phase radioimmunoassay with mouse monoclonal antibody, OC 125, plasma CA 125 levels were significantly elevated in stage III (mean +/- SEM = 32.7 +/- 5.2 U/ml, n = 17, p = less than 0.01) and stage IV endometriosis (37.2 +/- 10.5 U/ml, n = 6, p = less than 0.005) compared with levels during the follicular (15.9 +/- 1.5 U/ml, n = 12) and secretory phases (15.8 +/- 1.3 U/ml, n = 15) of control women and users of oral contraceptives (15.5 +/- 1.2 U/ml n = 10). However, CA 125 levels were not significantly elevated in women with stage I (16.6 +/- 2.0 U/ml, n = 28) or stage II endometriosis (17.9 +/- 2.1 U/ml, n = 13). Peritoneal fluid levels of CA 125 (n = 14) were significantly higher (2 to 9.3 times) than the corresponding paired plasma levels in participants with stage I, II, or III endometriosis. In patients treated with danazol (n = 10) or buserelin (n = 17), plasma CA 125 levels decreased significantly by midtherapy, remained suppressed at the end of therapy, but rebounded to near pretreatment levels 6 months after treatment was completed. With gestrinone therapy a similar decline was observed but became significant only at the end of therapy. Our findings indicate that elevated plasma CA 125 levels may prove useful in the management of endometriosis.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1988

Relationship between low- and high-affinity glucose transport systems of Saccharomyces cerevisiae.

The high-affinity glucose transport process in Saccharomyces cerevisiae whole cells was regulated by catabolite repression and inactivation. The low-affinity process was constitutive, and its activity was inhibited in proportion to the extent of derepression of the high-affinity process. The latter finding suggests that there is some regulatory relationship between the two processes.

Cell Membrane↗