Venoarteriolar reflex responses in diabetic patients.

The aim of this study was to investigate the venoarteriolar reflex (VAR) responses in type 1 (T1DM) and type 2 (T2DM) diabetes mellitus (DM) with polyneuropathy and to estimate their relationship with age, DM duration, initial cutaneous temperature and body mass index. Four groups of subjects were investigated: 1st group -20 patients with T1DM; 2nd group -50 patients with T2DM; 3rd group of 20 healthy subjects with similar age and body mass index (BMI) to the T1DM group; 4th group (Control2) of 24 healthy subjects adjusted by age and BMI to the T2DM group. The cutaneous perfusions of the big toe pulp were monitored as baseline perfusions at a temperature of 32°C in supine and sitting position with hanging legs and back in supine position. Loss of venoarteriolar reflex responses was established in 75% of T1DM patients, 78% of T2DM patients and in none of the investigated healthy controls. Reduced venoarteriolar perfusion responses were established in both T1DM and T2DM patients with polyneuropathy compared with healthy subjects. Reliable positive associations between VAR responses and the age, DM duration and initial cutaneous temperature were found.

Microvascular reactivity to thermal stimulation in patients with diabetes mellitus and polyneuropathy.

The study aimed to investigate local thermally induced microvascular reactivity in patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM) and polyneuropathy and to compare it with healthy controls. A hundred and fourteen subjects were investigated divided into 3 groups: 1st group -20 patients with T1DM; 2nd group -50 patients with T2DM; 3rd group -44 healthy controls. The skin perfusions of the first tiptoe were monitored by laser Doppler flowmetry during thermal test. The initial (PUi) and basal perfusions at 32°C (PUb) tended to be higher in the DM groups and the PUb of T1DM group was higher compared with the healthy subjects. The perfusion responses to heating were attenuated in the patients compared with the controls. The calculated vasodilator heat-induced indices were significantly lower and the vasoconstrictor indices during relative cooling in the recovery period were significantly higher in DM patients related to the healthy subjects. The reduced cutaneous microvascular responses to local thermal stimulation in the plantar sides of the toes of both T1DM and T2DM patients with polyneuropathy were similar to those found by previous studies in other investigated sites of glabrous and nonglabrous skin of patients with DM.

Hemorheological disturbances in cerebrovascular diseases.

The aim of the study was to evaluate the possible relationship of the hemorheological disturbances with the clinical symptoms and some risk factors (RF) for cerebrovascular diseases (CVD). The study included 68 patients with CVD, 29 with transient ischemic attacks (TIA) and 39 with chronic unilateral cerebral infarctions (UCI) and 47 healthy control subjects. A questionnaire for RF for CVD was filled. Hemorheological variables: leucocytes, hemoglobin, hematocrit, fibrinogen (Fib), plasma (PV) and whole blood viscosity (WBV) at different shear rates by Couette rotational viscometer Contraves Low Shear 30 were investigated and the hemorheological indices of erythrocyte aggregation (IEA), erythrocyte deformability (IED) and of oxygen transport to tissues (TO(2)) were calculated. The arterial hypertension was the most frequent RF in the examined patients'. The hemorheological investigation showed significant increase of Fib in the patients with TIA and of PV and WBV in both patients' groups. The comparative study of the hemorheological variables with the RF for CVD showed predominating significant correlations with blood pressure (systolic, diastolic and mean) values, with age, cholesterol, physical activity and the body mass index. Our study confirms the possibility the hemorheological variables to be accepted as RF for development of stroke and for its recurrences.

Orthostatic dysregulation in progressive autonomic failure--a transcranial Doppler sonography monitoring.

Hemodynamic changes associated with orthostatic hypotension in one patient with pure progressive autonomic failure (PAF) were studied by a passive (70 degrees tilt of the upper part of the body) and an active orthostatic tests. Mean blood pressure (MBP), heart rate (HR) and mean blood flow velocity (MFV) during transcranial Doppler sonography monitoring of the right middle cerebral artery (RMCA) were determined after 10 minutes of rest and after 1, 10 and 60 minutes passive 70 degrees tilt or active standing. Simultaneously, plasma norepinephrine (NE) levels during recumbency and after 1 and 10 min of the orthostatic manoeuvres were measured. Stand-up tilting induced slight decrease in MBP and MFV without changes in HR. Changes of systemic hemodynamics occurred during the first minute of passive standing and they increased within the first hour however the cerebral hemodynamics remained relatively stable. Active standing was accompanied by a severe decrease in the MBP and the MFV in RMCA, and an increase in vascular resistance immediately after the upright position. The hemodynamic changes were not followed by a secondary cardiac acceleration; they increased within the first minute of active standing and evoked a syncope. During squatting as a self-selected preventive mechanism in our patient an increase in MBP and MFV in RMCA occurred. Plasma NE levels in recumbency were lower than the reference values; they decreased with 12.1% after 10 min of passive tilting and with 24.8% after the first minute of active standing. These results showed that PAF is accompanied by a severe orthostatic dysregulation during active standing, associated with a progressive peripheral autonomic deficiency and disturbed mechanisms against gravitational pooling of the blood to the lower extremities. The orthostatic autoregulation of the cerebral hemodynamics seems to be preserved.

Asymmetry in walking performance and postural sway in patients with chronic unilateral cerebral infarction.

The asymmetrical nature of hemiparetic gait is well known; however, the role of walking asymmetry for speed performance is unclear. The purpose of the present study was to determine whether the range of walking speeds in chronic hemiparetic patients is associated with their gait asymmetry and postural sway. Twenty ambulatory patients with chronic unilateral supratentorial infarction were studied. Foot-ground contact patterns during swing and stance phases at various self-selected walking speeds were analyzed. The magnitude and direction of asymmetry in durations of stride phases were evaluated and compared with healthy subjects. Posturographic studies were performed to estimate the postural sway during quiet standing. Hemiparetic patients walked slower, more asymmetrically, and swayed more laterally favoring their nonaffected leg than did healthy persons. Although there was variability in durations of stride phases when comparing the two sides, a prolonged swing on the affected side and a prolonged stance on the nonaffected side were observed in all patients. The magnitude of asymmetry in stride phases varied among the patients; however, it was significantly higher than in controls (p < 0.03). Increased mean lateral sway during quiet standing was indicative of restricted velocity performance during walking. Patients with higher swing asymmetry achieved their maximum speed performance at lower velocity levels. However, the ability of patients to ambulate with a number of self-selected speeds was not associated with the magnitude of their overall gait asymmetry. Patients with right hemisphere lesions appeared to have less ambulatory ability than patients with left hemisphere lesions.

Effects of aging and hematocrit on cerebral blood flow velocity in patients with unilateral cerebral infarctions: a Doppler ultrasound evaluation.

By means of conventional continuous-wave (CW) (4 MHz) and transcranial pulsed (2 MHz) Doppler sonography 50 patients (34 men and 16 women, mean age 58.6 +/- 7.6 years) who survived unilateral cerebral infarctions (UCI) in the middle cerebral artery (MCA) territory were investigated. The control group consisted of 30 presumed healthy age-matched persons. The main quantitative sonographic parameters of the major arteries of the head and the basal cerebral arteries were evaluated. On the day of the neurosonographic investigations, hematocrit (Hct) was determined. Low-degree stenoses of the internal carotid arteries were found in 26 (52%) of the patients. Increased intracranial vessels' resistance in the MCA on the infarction side was usually obtained. Decreasing of Doppler shift frequency with advancing age and increasing of Hct was established in the controls. In patients with UCI the effects of aging and Hct on the sonographic parameters of the collateral arteries were more pronounced. Obviously, in patients with UCI, the alterations of the sonographic parameters are caused by parallel influence of vessels' disease, age-defined changes of vessels' walls, and viscosity variations.

Adenohypophyseal hormones and catecholamines in patients with diencephalic pathology.

The study involved 75 patients with diencephalic pathology (58 females and 17 males, mean age 39 years). All patients underwent thorough somatic and neurological check up and examination of the autonomic nervous system as well. The etiology was considered to be infection in 60 patients (60%) and brain injury in the other 15 (20%). Paroxysmal disturbances were established in 23 patients, while in the other 52, the clinical manifestation had a permanent course. Changes in adenohypophyseal (TTH, GH, FSH, LH, ACTH and RRL) hormones were established and for mean basal plasma levels of FSH these changes were statistically significant (p less than 0.05). Catecholamine metabolism was impaired in the patients with diencephalic pathology, manifested by elevation of the urinary levels of dopamine, noradrenaline and adrenalin. The role of adenohypophyseal hormones and catecholamines for the pathogenesis of diencephalic dysfunctions is discussed.