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At least 505 records · Page 28Linked to original sources
PubMed2000

Autonomic dysfunction and urinary albumin excretion rate are associated with an abnormal blood pressure pattern in normotensive normoalbuminuric type 1 diabetic patients.

OBJECTIVE: To analyze the role of autonomic function and other possible factors associated with a blunted fall in nocturnal blood pressure. RESEARCH DESIGN AND METHODS: A total of 39 normotensive normnoalbuminuric type 1 diabetic patients were studied. Glomerular filtration rate (51Cr-EDTA technique), extracellular volume (51Cr-EDTA distribution volume), and urinary albumin excretion rate (UAER) (by radioimmunoassay) were measured. The subjects' 24-h ambulatory blood pressure and a 24-h electrocardiogram were recorded simultaneously Heart rate variability was calculated in the time domain for 24 h, in the frequency domain at night, at rest in the supine position, and during tilt. Patients were classified according to diastolic blood pressure (dBP) night/day ratio as dipper patients (< or =0.9) and nondipper patients (>0.9). RESULTS: Nondipper patients presented a higher low-frequency (LF) component (a sympathetic index) and higher LF/high-frequency (HF) ratio during sleep than dipper patients (0.29 +/- 0.12 vs. 0.19 +/- 0.10 normalized units [n.u.], P = 0.008; and 0.98 +/- 0.53 vs. 0.55 +/- 0.45 n.u., P = 0.007, respectively). At rest, the LF component in nondipper patients (0.38 +/- 0.13 n.u.) was higher than in dipper patients (0.27 +/- 0.12 n.u., P = 0.04). After the tilt, nondipper patients did not show an increase in the LF component (P = 0.32), but in dipper patients, the increase was significant (P = 0.001). In both groups, tilting promoted a decrease in the HF component (a parasympathetic index). In a stepwise multiple linear regression analysis, the LF component during sleep and the UAER accounted for 24% of the variability in the dBP night/day ratio. CONCLUSIONS: The predominance of sympathetic activity and increased levels of UAER, although within the normal range, are associated with a blunted fall in nocturnal dBP in normoalbuminuric normotensive type 1 diabetic patients.

Adult↗
PubMed2005

Autonomic dysfunction in ALS: a preliminary study on the effects of intrathecal BDNF.

This pilot study aimed at exploring the effects of intrathecally administered brain derived neurotrophic factor (BDNF) on autonomic functions in patients with ALS. A battery of autonomic sympathetic and parasympathetic tests was performed at baseline and after nine months of treatment in 10 ALS patients participating in a double-blind placebo-controlled phase II/III study of intrathecally administered BDNF. Results of patients treated with BDNF (25 or 150 microg/day) were compared to those receiving placebo. Sudomotor function and blood pressure response to handgrip significantly worsened during the treatment period (55.4+/-26.1 vs. 38.9+/-23.9 g/m(2)h, p<0.05; 20+/-6 vs. 13+/-4 microHg, p<0.05) whereas other sympathetic and all parasympathetic function tests only tended to be more abnormal at follow-up. Serum norepinephrine levels increased significantly during the nine-months observation period. The results of autonomic function tests were not different between patients treated with BDNF and placebo, but norepinephrine levels were higher in the BDNF group. We conclude that autonomic nervous system function deteriorates along with poorer motor performance independently from treatment with BDNF. The elevation of norepinephrine levels might reflect a non-specific up-regulation, and its association with BDNF an autocrine effect.

Adult↗