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Nocturnal Increase (nocturnal + increase)
Selected AbstractsCardiac Autonomic Control in Patients with Refractory Epilepsy before and during Vagus Nerve Stimulation Treatment: A One-Year Follow-up StudyEPILEPSIA, Issue 3 2006Eija Ronkainen Summary:,Purpose: To elucidate possible effect of vagus nerve stimulation (VNS) therapy on interictal heart rate (HR) variability in patients with refractory epilepsy before and after 1-year VNS treatment. Methods: A 24-hour electrocardiogram (ECG) was recorded at the baseline and after 12 months of VNS treatment in 14 patients with refractory epilepsy, and once in 28 healthy age- and sex-matched control subjects. Time and frequency domain measures, along with fractal and complexity measures of HR variability, were analyzed from the ECG recordings. Results: The mean value of the RR interval (p = 0.008), standard deviation of N-N intervals (SDNN) (p < 0.001), very-low frequency (VLF) (p < 0.001), low-frequency (LF) (p = 0.001), and high-frequency (HF) (p = 0.002) spectral components of HR variability, and the Poincaré components SD1 (p = 0.005) and SD2 (p < 0.001) of the patients with refractory epilepsy were significantly lower than those of the control subjects before VNS implantation. The nocturnal increase in HR variability usually seen in the normal population was absent in patients with refractory epilepsy. VNS had no significant effects on any of the HR-variability indexes despite a significant reduction in the frequency of seizures. Conclusions: HR variability was reduced, and the nocturnal increase in HR variability was not present in patients with refractory epilepsy. One-year treatment with VNS did not have a marked effect on HR variability, suggesting that impaired cardiovascular autonomic regulation is associated with the epileptic process itself rather than with recurrent seizures. [source] Diurnal rhythms in neurohypophysial functionEXPERIMENTAL PHYSIOLOGY, Issue 2000Mary L. Forsling The neurohypophysial hormones oxytocin and vasopressin show daily rhythms of secretion with elevated hormone release during the hours of sleep. This pattern can be modulated by ovarian steroids and alters with age. The pattern appears to be due in part to the nocturnal increase in melatonin secretion, which stimulates hormone release in man, while being inhibitory in the rat. Pinealectomy alters both the 24 h pattern of neurohypophysial hormone release in the rat and the firing rate of magnocellular supraoptic nucleus neurones. There is also a reduced hormone release in response to hypovolaemia and raised plasma sodium concentration compared to sham operated animals, with a smaller increase in neuronal activity, as determined by immediate-early gene expression. The normal responses can be restored by nocturnal administration of melatonin. Melatonin also influences the neurohypophysial hormone response in the human to known stimuli of release, such as raised plasma osmolality, exercise and insulin-induced hypoglycaemia. Recent studies have revealed that not only does the release of vasopressin and oxytocin vary over each 24 h, but the respective renal and pregnant uterine responses also show diurnal variations. [source] Modulation of Aanat gene transcription in the rat pineal glandJOURNAL OF NEUROCHEMISTRY, Issue 2 2010Anthony K. Ho Abstract The main function of the rat pineal gland is to transform the circadian rhythm generated in the suprachiasmatic nucleus into a rhythmic signal of circulating melatonin characterized by a large nocturnal increase that closely reflects the duration of night period. This is achieved through the tight coupling between environmental lighting and the expression of arylalkylamine- N -acetyltransferase, the rhythm-controlling enzyme in melatonin synthesis. The initiation of Aanat transcription at night is controlled largely by the norepinephrine-stimulated phosphorylation of cAMP response element-binding protein by protein kinase A. However, to accurately reflect the duration of darkness, additional signaling mechanisms also participate to fine-tune the temporal profile of adrenergic-induced Aanat transcription. Here, we reviewed some of these signaling mechanisms, with emphasis on the more recent findings. These signaling mechanisms can be divided into two groups: those involving modification of constitutively expressed proteins and those requiring synthesis of new proteins. This review highlights the pineal gland as an excellent model system for studying neurotransmitter-regulated rhythmic gene expression. [source] Antidiuretic hormone in elderly male patients with severe nocturia: a circadian studyBJU INTERNATIONAL, Issue 4 2004Du Geon Moon OBJECTIVE To investigate the circadian variation of plasma antidiuretic hormone (ADH) and urine output in patients with severe nocturia (> three times per night) and to assess the effect of oral desmopressin on nocturnal urine output in these patients. PATIENTS AND METHODS Twelve patients with severe nocturia and five age-matched controls without were assessed over 24 h (circadian sampling) during a 72-h hospital admission. Blood levels of ADH and changes of urine output were measured in the patients before and after the oral administration of desmopressin (0.2 mg, at 22.00 hours in the second day), and in the controls not treated with desmopressin. RESULTS Compared with the normal control, the patients had no diurnal variation in urine output and greater nocturnal urine production, associated with a lack of nocturnal increase in ADH level. Compared with the baseline urine output, desmopressin significantly decreased night-time (23.00,08.00 hour) urine output in the patients (P < 0.05). Desmopressin significantly increased the osmolality of night-time urine (P < 0.05), and there was no systemic adverse reaction. CONCLUSIONS Severe nocturia in a large proportion of elderly men with lower urinary tract symptoms is caused by nocturnal polyuria and natriuresis, because they have no nocturnal increase in ADH. These results suggest that desmopressin may be effective in decreasing nocturnal urine production in patients with severe nocturia who do not respond to conventional treatment. [source] Circadian systemic haemodynamics in borderline and mild hypertensionCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 6 2000R. Takalo Circadian variations in blood pressure (BP), stroke volume (SV), heart rate (HR), cardiac output (CO) and total peripheral resistance (TPR) were determined by a pulse contour method from the intra-arterial pulse wave in 32 normotensive (NT), 32 borderline hypertensive (BHT) and 31 hypertensive (HT) middle-aged men. Daytime averages were used as the reference levels. The nocturnal decrease in BP and HR were similar in the three groups. In the night, SV did not change in the NT group, but was increased in the BHT and HT groups. The nocturnal increase in SV may reflect reduced venous capacity causing increased cardiac filling. As a consequence of the difference in SV, the nocturnal CO fall was diminished in the HT group as compared with the NT group. Moreover, TPR had a tendency to decrease in the HT group, which may be considered as a baroreflex response to buffer the expected rise in BP. Five years later, 25 NT, 24 BHT and 19 HT subjects were reassessed using casual BP measurements. In the NT and BHT groups, six and 17 subjects, respectively, had progressed to hypertension. In a logistic regression model for those who became HT, the nocturnal increase in SV was a significant predictor for future hypertension. In conclusion, the results suggest that circadian systemic haemodynamics may be altered before BP is markedly elevated, and that haemodynamic studies might be useful in predicting the development of sustained hypertension. [source] | |||||||||||||