Search results for "circadian rhythm"

A study of factors that may influence the determination of copper, iron, and zinc in human milk during sampling and in sample individuals.

1999

The aim of this study was to establish the possible effects of the sampling protocol (between-breast, within-feed, and diurnal differences) and the mother's personal factors (age, parity, iron supplementation, smoking habits, and lactation period) on the copper, iron, and zinc contents in human milk. One hundred thirty-six human milk samples identified by their origin and sampling conditions were analyzed. The samples were obtained from the 2nd to 15th d postpartum from 62 women. The data on the individuals required for the study were available. Mineral determinations were analyzed by flame atomic absorption spectrometry following a standardized protocol. The results showed that iron conten…

Increase in Nocturnal Blood Pressure and Progression to Microalbuminuria in Type 1 Diabetes

2002

Patients with type 1 diabetes mellitus and microalbuminuria often have elevated blood pressure while they are asleep, but it is not known whether the elevation develops concomitantly with microalbuminuria or precedes it.We monitored 75 adolescents and young adults who had had type 1 diabetes with normal urinary albumin excretion and blood pressure for more than five years. Ambulatory blood-pressure monitoring was used to assess blood pressure at the initial evaluation and about two years later, at which time all subjects had normal urinary albumin excretion. Subsequently, subjects were monitored for the development of microalbuminuria.Microalbuminuria developed in 14 subjects, whereas the o…

Time of day effects on isometric and isokinetic torque developed during elbow flexion in humans

2001

The aim of this study was, firstly, to confirm or refute the existence of circadian rhythms during several velocities of concentric action of the elbow flexor muscles and, secondly, to compare the characteristics of these circadian rhythms with those obtained during isometric actions. Eight volunteer subjects participated in this study. The circadian rhythms were obtained from six test sessions (TS) carried out at different times of day over 6 days with only one TS a day. During each TS, oral temperature and the torque of the muscle action were measured. The subjects made, on an isokinetic ergometer, two maximal isokinetic concentric elbow flexions at five angular velocities (60, 120, 180, …

Micro-albuminuria as a predictor of cardiovascular damage in essential hypertension

1989

Microalbuminuria fractional clearance and early renal permselectivity changes in essential hypertension.

1992

In order to verify if, in essential hypertension (EH), the microalbuminuria (AER) increase could be due to hemodynamic modifications or to glomerular structural changes, in 15 essential hypertensives (EHs) with 24-hour AER16 micrograms/min and in 15 EHs with 24-hour AERor = 16 micrograms/min, the day- and nighttime behavior of creatinine clearance (Ccr), as well as AER clearance (AER-C) and fractional clearance (AER-FC), and behavior of blood pressure (BP) was evaluated. Patients with 24-hour AER16 micrograms/min showed significantly higher values of 24-hour and daytime Ccr than the other group of EHs, while during the night period, there were no significant differences between the two grou…

Developmental Changes and Daily Rhythm in Melatonin-Induced Inhibition of 3′,5′-Cyclic AMP Accumulation in the Rat Pituitary

1990

Melatonin's transduction mechanisms were investigated using in vitro cultured anterior hemipituitaries. Melatonin inhibited cAMP and 3',5'-cyclic GMP accumulation in neonatal rat anterior pituitary stimulated with LHRH. Maximal inhibitory effect was reached within 25 min and persisted for at least 20 min. Inhibition of cAMP accumulation is specific for melatonin because its analogs N-acetylserotonin and 5-methoxytryptamine are 1000 times less potent. Melatonin effect is age- and time-dependent. Marked inhibition was observed in 5-, 10-, and 14-day-old rats but not in 29-day-old ones. Melatonin was significantly more potent when applied at the end of the light period as compared with the fir…

Impaired circadian heart rate variability in Parkinson’s disease: a time-domain analysis in ambulatory setting

2020

Abstract Background Heart rate variability (HRV) decreases in Parkinson’s disease (PD) and it can be considered a marker for cardiovascular dysautonomia. The purpose of this pilot study is to evaluate long-term time-domain analysis of HRV of PD patients and compare the results with those of matched healthy individuals. Methods Idiopathic PD patients without comorbidity impairing HRV, and age-matched healthy individuals were recruited in a pilot study. A long-term time domain analysis of HRV using 24-h ambulatory ECG was performed. Results Overall, 18 PD patients fulfilling inclusion criteria completed the evaluation (mean age was 55.6 ± 8.8, disease duration: 5.0 ± 4.7). Mean SCOPA-AUT scor…

Evidence for a dysfunction and disease-promoting role of the circadian clock in the diabetic retina.

2021

Diabetic retinopathy is a major complication of chronic hyperglycemia and a leading cause of blindness in developed countries. In the present study the interaction between diabetes and retinal clocks was investigated in mice. It was seen that in the db/db mouse - a widely used animal model of diabetic retinopathy - clock function and circadian regulation of gene expression was disturbed in the retina. Remarkably, elimination of clock function by Bmal1-deficiency mitigates the progression of pathophysiology of the diabetic retina. Thus high-fat diet was seen to induce histopathology and molecular markers associated with diabetic retinopathy in wild type but not in Bmal1-deficient mice. The d…

The effects of 12-week progressive strength training on strength, functional capacity, metabolic biomarkers, and serum hormone concentrations in heal…

2018

Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strengt…

Home blood pressure control is low during the critical morning hours in patients with hypertension: the SURGE observational study

2011

Background. The morning blood pressure (BP) surge is associated with a peak increase in vascular events. Objective. The aim of this observational study was to evaluate morning BP control in treated hypertensive patients using home BP (HBP) monitoring and to compare these findings with clinic BP control. Methods. Clinic BP was measured twice during a 2-week period, prior to medication. Seated HBP was measured, using a BHS-validated device, three times per day over a 2-week period. Assessments included morning (06:00–11:59), lunchtime (12:00–14:00) and evening (18:00–22:00) HBP control (all <135/85 mmHg) and clinic BP (<140/90 mmHg) control. Results. A total of 15 618 patients were assessed. …