Bacterial contamination and the transport vial material affect cerebrospinal fluid concentrations of β-Amyloid and Tau protein as determined by enzyme immunoassay.

Background/aims: Determination of marker proteins of neuronal degeneration in cerebrospinal fluid (CSF) is of increasing importance. However, preanalytical problems may compromise the results.

Methods: We studied the influence of the transport tube material and shaking at room temperature on the CSF concentrations of β-amyloid and tau protein determined by enzyme immunoassays.

Differential effects of surgical sympathetic block at the T2 and T4 level on vasoconstrictor function.

Endoscopic sympathetic block (ESB) is used as a treatment of excessive palmar sweating. In a prospective study we compared the effect of ESB at the level of the second (T2) and fourth thoracic ganglion (T4) on vasoconstriction and sweating of the hands. Sympathetic vasoconstriction was measured by computerassisted infrared thermography following ice water immersion of the hands in 22 hyperhidrosis patients before, two days and 3 months post op.

Effects of gender and level of surgical sympathetic block on vasoconstrictor function.

Interruption of sympathetic outflow by surgical sympathetic block has been used to treat hyperhidrosis for decades. In this study the effect of gender and the level of sympathetic block (T2 vs. T3) on the rewarming kinetics following ice water immersion were assessed in a prospective study on 60 hyperhidrosis patients before, 2 days, and 3 months postoperatively.

Differential effects of surgical sympathetic block on sudomotor and vasoconstrictor function.

Objective: To assess the effects of a surgical block of the sympathetic chain at the T2 level on vasoconstriction and palmar sweating in patients with palmar hyperhidrosis.

Methods: In a prospective study, sympathetic vasoconstriction was measured by laser-Doppler imaging and by computer-assisted infrared thermography (rewarming kinetics following immersion of both hands in ice water [4 degrees C, 30 seconds]) in 61 patients with hyperhidrosis preoperatively and 2 days and 3 months postoperatively. In addition, palmar sweating preoperatively and 3 months postoperatively was assessed by quantitative sudometry.

Combination of pressure and velocity parameters in the non-invasive diagnosis of aorto-iliac disease.

Three different femoral artery flow velocity parameters in combination with segmental pressure measurements were evaluated for their respective diagnostic value in identifying the presence or absence of hemodynamically significant aorto-iliac disease. A total of 60 patients (119 legs) were examined both non-invasively and with arteriography. Doppler flow velocities were recorded using a 5-MHz CW Doppler velocity metering system.

Effect of long-term electrical stimulation of rabbit fast muscles on the reactivity of their supplying arteries.

Rabbit fast hindlimb muscle (tibialis anterior, extensor digitorum longus and peroneal muscles) were stimulated for 14 days, 8 h/day using implanted electrodes, with two different frequencies of stimulation (continuous at 10 Hz or 3 bursts/min at 40 Hz) giving the same total number of stimuli. Both patterns of stimulation resulted in a different pattern of flow and perfusion pressure, with lowered perfusion pressure during contractions in muscles stimulated at 10 Hz and intermittent increase during the peak of tetanic contractions in muscle stimulated at 40 Hz. The arteries supplying the stimulated muscle (anterior tibial artery) were then tested for reactivity to noradrenaline in vitro.

Sympathetic activity, lipids accumulation, and arterial wall morphology in rabbits at high altitude.

The purpose of this study was to investigate the effect of increased sympathetic nervous activity on arterial wall viability as reflected by its response to elevated plasma lipids. Our previous finding that vascular wall viability was reduced by low sympathetic nervous activity indicated that chronically enhanced sympathetic activity should have the opposite effect. In this study rabbits were divided into two groups, both of which received 1% cholesterol in the diet.

Morphometry of the amount of smooth muscle cells in the media of various rabbit arteries.

Our objective in this study was to evaluate the relative amount of smooth muscle cells in the medial layer of various rabbit arteries. The fixation of smooth muscle cells in the arterial wall is difficult and the differential effect of glutaraldehyde (GA) and fixative vehicle on cell ultrastructure in different tissues is controversial. We compared the effect of various concentrations of the vehicle and glutaraldehyde (osmolarity ranges for total fixative, 350-1030 mOsm) on the arterial wall ultrastructure.

Aortic enzymes and lactate in high altitude-raised and cholesterol-fed rabbits.

Fourteen male rabbits born at elevation 4000 ft (first experimental series) were transferred at age of 2 months to elevation 12470 ft and raised there for 18 weeks. Half of the animals remained on a commercial rabbit chow (group H) while the other half was on the same diet supplemented with cholesterol (group C). Eight male rabbits raised at sea level served as controls (group S).

Trophic effect of the sympathetic nervous system on vascular smooth muscle.

While the vasomotor effect of the sympathetic nervous system (SNS) on the arterial wall is well recognized, its trophic function is not. It is the aim of these studies to demonstrate this all-important function as it relates to the vascular muscle. Although the exact mechanism by which sympathetic nerve impulses influence the metabolism of the vessel wall is unknown, effects of sympathectomy can be demonstrated.

Genetic difference in the sympathetic nervous activity and susceptibility to atherosclerosis in pigeon.

Norepinephrine (NE) accumulation, dose response to NE and NE content were studied in the aortas of White Carneau (WC) and Show Racer (SR) pigeons in order to determine if a correlation exists between the atherosclerosis susceptibility of WC and atherosclerosis resistance of SR with the degree of sympathetic nerve ending activity. In addition, the age factor was included by comparing results in 4-14 month-old and 5-year-old animals. NE accumulation by abdominal aorta samples from SR pigeons of both age groups and by thoracic segments from 5-year-old SR was significantly higher than that by WC pigeon samples.

Combined effect of cholesterol feeding and sympathectomy on the lipid content in rabbit aortas.

There is indirect evidence that sympathetic innervation may have an effect on the metabolic rate of the vessel wall. to shed some light on this question, this investigation was designed to study whether or not diminished adrenergic nerve activity in the arterial wall leads to greater susceptibility to atherosclerosis. A total of 48 rabbits was studied of which, 26 were chemically sympathectomized.

Evaluation of long-term chemical sympathectomy in adult rabbits.

Administration of 6-hydroxydopamine (6-OHDA) will produce long-term sympathectomy in newborn animals. This investigation was designed to determine whether or not a long-term sympathectomy can be achieved by repeated administration of 6-OHDA in adult rabbits. Chronic treatment with 6-OHDA lowered blood pressure on average of 9 mmHg; the carotid sinus reflex was depressed, in contrast to the pressure response to intravenously administered epinephrine, which was doubled.

A noncontact method for three-dimensional analysis of vascular elasticity in vivo and in vitro.

A new method is described to measure the deformation of the blood vessel wall simultaneously in longitudinal and circumferential directions. This information is of paramount importance for further characterization of the elastic properties of the arterial wall. The new method consists of a closed-circuit TV system in conjunction with a video dimension analyzer (VDA).

Microvascular pressure distribution in skeletal muscle and the effect of vasodilation.

In cats anesthetized with pentobarbital, 188 direct microvascular pressure and diameter measurements were made of the tenuissimus muscle. The microvascular pressure in arterioles of 70 mum in diameter or larger was proportional to the systemic arterial pressure (PA). The arterioles with diameter-s ranging from 35 to 20 mum have been shown to be the principa-l source of arteriolar resistance regulating micropressures downstream.