Photoplethysmography pulse rate variability as a surrogate measurement of heart rate variability during non-stationary conditions.

In this paper we assessed the possibility of using the pulse rate variability (PRV) extracted from the photoplethysmography signal as an alternative measurement of the HRV signal in non-stationary conditions. The study is based on analysis of the changes observed during a tilt table test in the heart rate modulation of 17 young subjects. First, the classical indices of HRV analysis were compared to the indices from PRV in intervals where stationarity was assumed. Second, the time-varying spectral properties of both signals were compared by time-frequency (TF) and TF coherence analysis. Third, the effect of replacing PRV with HRV in the assessment of the changes of the autonomic modulation of the heart rate was considered. Time-invariant HRV and PRV indices showed no statistically significant differences (p > 0.05) and high correlation (>0.97). Time-frequency analysis revealed that the TF spectra of both signals were highly correlated (0.99 +/- 0.01); the difference between the instantaneous power, in the LF and HF bands, obtained from HRV and PRV was small (<10(-3) s(-2)) and their temporal patterns were highly correlated (0.98 +/- 0.04 and 0.95 +/- 0.06 in the LF and HF bands, respectively) and TF coherence in the LF and HF bands was high (0.97 +/- 0.04 and 0.89 +/- 0.08, respectively). Finally, the instantaneous power in the LF band was observed to significantly increase during head-up tilt by both HRV and PRV analysis. These results suggest that although some differences in the time-varying spectral indices extracted from HRV and PRV exist, mainly in the HF band associated with respiration, PRV could be used as a surrogate of HRV during non-stationary conditions, at least during the tilt table test.

[Cochlear implants in Aragón]. / Diez años de implantación coclear en Aragón.

Cochlear implants are, actually, one of the major advances in the treatment for profound deafness. His use is, already, a routine in the daily practice of our specialty. Due to its special aspects, cochlear implants have to be done following a protocol that organizes and coordinates the different aspects of the diagnoses and treatment of profound deafness, in the different administrative and geographical fields. The health system in our country and the smale dimension of our area, has taken us to create and follow a special program in which all the available resources are used. Following this protocol, we have performed 63 cochlear implants, in the last 10 years. We show here the results and complications.

[Sleep disorders in multiple sclerosis]. / Trastornos del sueño en la esclerosis múltiple.

INTRODUCTION: To determine the frequency of sleep disorders in multiple sclerosis (MS) patients and their relation with other manifestations of the disease. METHODS: Selected patients had clinically definite MS (relapsing-remitting and secondary progressive forms) and duration of the disease over two years. They were serially evaluated at the unit of demyelinating diseases of a third level hospital. The following scales were applied: the Pittsburgh Sleep Quality Index, the Hamilton Depression Rating Scale, EDSS, ISS and ESS. Statistical analysis by means of non parametric test and logistic regression was carried out. RESULTS: One hundred patients were included (72% women and 28% males). Mean age was 39 years. Eighty eight were relapsing-remitting forms and the rest secondary progressive forms. Mean EDSS was: 2.5. Mean duration of evolution: 11.2 years. The prevalence of sleep disorders was 36%. Age, sex, evolutionary form, degree of disability and chronic fatigue did not relate with the sleep disorders in these patients. In the multivariant analysis by means of logistic regression, we found that every point more in Hamilton's scale multiplies the probability of presenting sleep disorders by 1.2. CONCLUSIONS: Depression is the only variable that independently relates, with the presence of sleep disorders in MS patients.

[Evolution study in children with suspected obstructive sleep apnea]. / Datos evolutivos en niños estudiados por sospecha de síndrome de apnea del sueño.

INTRODUCTION: Obstructive sleep apnea syndrome is a common disorder in childhood with an uncertain evolution. OBJECTIVES: Study of children's clinical evolution with suspected diagnosis of OSAS, which was carried out after two years of an overnight polisomnogram. PATIENTS AND METHODS: 73 children were studied. We evaluated if they had been operated and what type of surgery was performed, Brouillete Scale and subjective impressions. We have correlated: age, clinical evolution and surgery. RESULTS: Age was inversely correlated with changes in Brouillete (r=-0.39, p=0.002), standing out that children that underwent surgery were younger (4.1 vs. 7.0 years, Student t: -4.22, p=0.00009). Without the influence of age, the difference between evolution in operated and not operated ones was not significative, statistically speaking, but it was if we analysed the different types of surgery by themselves (Snedecor F: 3.9, p=0.007), tonsillectomy was the larger. CONCLUSION: The middle-term evolution in children with OSAS is good if we use the correct treatment.

Glomerulonephritis and immunosuppression associated with dietary essential fatty acid deficiency in gilthead sea bream, Sparus aurata L., juveniles.

An experiment was conducted to determine the effect of an essential fatty acid (EFA) deficient diet on growth, immune status and renal morphology of juvenile gilthead sea bream, using two diets: a control diet containing 2% (DW) of n-3 high unsaturated fatty acid (n-3 HUFA) and a diet formulated to be deficient in EFA for this species and containing 0.5% DW of n-3 HUFA (diet NFA). After 9 weeks of feeding the EFA-deficient diet fish showed a reduction in growth compared with the control group (107.48 +/- 9.14 and 123.14 +/-11.87 g final weight respectively). Fish fed the NFA diet showed a reduction in the erythrocyte volume together with increased erythrocyte fragility, haemoglobin content and red blood cell count in comparison with fish fed the control diet. EFA deficiency also reduced cellular immunity in terms of neutrophil activity and the number of circulating lymphocytes. The serum alternative complement pathway was markedly reduced in fish fed the EFA deficient diet. Fish fed the control diet showed glomeruli with a well-defined Bowman's space and normal renal tubes. However, up to 88% of fish fed the EFA-deficient diet showed alterations in renal morphology affecting at least 50% of the glomeruli, which showed extreme dilation of capillaries and occlusion of Bowsman's capsule. Mesangial proliferation and diffuse thickening of the capillary walls, as well as renal tube degeneration, were also observed.

Low vitamin E in diet reduces stress resistance of gilthead seabream (Sparus aurata) juveniles.

This study investigates the effect of dietary vitamin E on juveniles of gilthead seabream under stressful situations, focusing on the effects on growth, haematology, some immune parameters and plasma cortisol as indicators of stress. Two sardine meal-based experimental diets, one of them supplemented with 150 mg of alpha tocopherol kg(-1) of diet (control) and another one without vitamin E supplementation (diet NE), were assayed under two different stress conditions: overcrowding as a chronic stressor (during 15 weeks) and repetitive chasing as an acute repetitive stressor. Low levels of vitamin E in the diet depleted alternative complement pathway activity [from 167.23 U ml(-1) (control fish) down to 100.99 U ml(-1)] and also nonspecific haemagglutination. Also, fish fed a non-supplemented diet showed an elevation of plasma cortisol basal levels without a stressor influence [from 3.91 ng cortisol ml(-1) plasma (control fish) up to 21.70 ng cortisol ml(-1) plasma]. Low levels of vitamin E in the diet also produced an increase of erythrocyte fragility. Under chronic stress, fish fed the vitamin E-deficient diet showed a reduction in growth and survival, and alterations in haematological parameters, such as an additional haemoconcentration in response to overcrowding when compared with control fish. Under repetitive stress, fish fed the vitamin E deficient diet showed faster elevation of plasma cortisol levels in response to stress and a lower survival rate than control fish. Production of oxygen radicals by blood neutrophils was reduced under repetitive stress in fish fed the non-supplemented diet. These results suggest that fish fed the vitamin E-deficient diet had lower stress resistance.

[Subjective sleep quality and spectral analysis of electroencephalography during nocturnal sleep]. / Calidad subjetiva de sueño y análisis espectral del electroencefalograma de sueño nocturno.

INTRODUCTION: The relation between subjective sleep quality and the stages of polysomnography is unclear. Computerized sleep analysis provides a reliable tool for the study of sleep dynamics. OBJECTIVE: To study the relation between subjective sleep quality and spectral EEG parameters during nocturnal sleep. MATERIAL AND METHODS: Nocturnal sleep were recorded ambulatory in 26 subjects aged from 8 to 63. The following variables were extracted from EEG signal (Fz-Pz) quantified through the Fast Fourier Transformation (FFT): delta maximum, spectral peak, delta sleep time, efficiency and desynchronized sleep. A sleep diary was administered in the morning to assess the subjective sleep quality. Multiple regression and Anova were used for statistical analysis. RESULTS: Efficiency and delta maximum became significant predictors accounting for 54% of subjective sleep variance. The item 'how was your sleep?' was answered in a different way according to the delta maximum. CONCLUSIONS: Sleep depth, measured by spectral analysis, is an important predictor of the subjective sleep quality. The sleep classification in discrete stages ignores this feature.

[Age as source of variation in various parameters of 'delta sleep']. / La edad como fuente de variación en algunos parámetros del 'sueño delta'.

INTRODUCTION: The clinic usefulness of a diagnostic test is in relationship to the precision with which measures the studied phenomenon. The lack of precision involve the reliability upon causing confounded results of the normal and diseased populations. OBJECTIVE: Since the sleep varies in function of the age, to find sleep parameters that fit better to the changes that the aging produces in the sleep. MATERIAL AND METHODS: Spectral analysis through the Fast Fourier Transformation of the ambulatory EEG of 28 healthy subjects. RESULTS: Maximum value of power (maximum depth) in a frequency of ended in a point of the sleep goes losing in a way specifies and systematical with the age. CONCLUSIONS: The variance accounted by this parameter is of the 87%, what, being tried to a phenomenon so variable as the sleep, supposes a interesting starting point to be applied to some pathologies in those which is presumed that the slow sleep (to which is attributed a paper in the cerebral restoration) is decreased.

Hematological recovery in Sparus aurata after bleeding. A time course study.

To determine the hematological recovery after blood loss in gilthead sea bream juveniles, an experimental anemia was induced by caudal blood extraction. Seventy fish were used for experimental hemorrhage and another 35 were used as controls. Blood samples were taken after 0.5, 1, 2, 4, 8, 16 and 32 days in both control and anemic groups. After bleeding, besides a reduction in the direct hematic constants, a peak in the mean cell volume value, together with a decrease in mean cell hemoglobin concentration after bleeding, suggested erythrocyte swelling. The increase in MCH suggested the occurrence of hyperchromic erythrocytes. Recovery of RBC number started between 2 and 4 days after bleeding and seemed to be related to erythroblast release to circulation. Total recovery was completed after 8 days of bleeding. The recovery patterns for hematological parameters of sea bream are discussed in relation to applied work on this species.

Nocturnal prolactin and growth hormone levels in children with complex partial and generalized tonic-clonic seizures.

This study measures whether there is a rise in the secretion of nocturnal prolactin and growth hormone (GH), during the delta phase of the first sleep cycle in children who are suffering from either complex partial or generalized tonic-clonic seizures. The findings are compared with those obtained in the control group of patients which is made up who suffer from pseudoseizures. There is a moderate but significant rise in the nocturnal prolactin plasma level in both types of infantile seizures. No significant difference was found in the GH.

[Tests for studying the secretion of growth hormone. Update]. / Pruebas de estudio de la secreción de hormona de crecimiento. Puesta al día.

Some tests to study the growth hormone secretion have been analysed. According to our own experience and to the present criteria the physiologic tests seem to be more suitable than the pharmacologic ones. In case of discordant results, those obtained in physiologic tests completed with the clinical data and if necessary with biologic probes are conclusive. The availability of GRF will allow the treatment of some cases of dwarfism of hypothalamic origin, that in our opinion are more frequent than those of pituitary origin. Otherwise the gene studies will contribute to the understanding of some cases of genetic dwarfism and make possible an appropriate genetic counseling.