Calf basal resting and reactive hypercemia blood flow were measured at 4-h intervals during a day in fifteen healthy subjects and in fifteen patients with intermittent claudication by means of a venous occlusion plethysmograph. Mathematical-statistical analysis of the data failed to demonstrate circadian periodicity of calf blood flow in healthy subjects, but proved the existence of a 24-h rhythm of calf basal resting and reactive hyperemia blood flow in patients with intermittent claudication. This different behavior of calf blood flow can be understood if one considers that in healthy subjects the voluntary muscles in the extremities have a blood supply which can be instantaneously adjusted over a large area. In patients with peripheral arterial disease, on the other hand, the vascular responses in voluntary muscles of the limbs to various endogenous or exogenous stimuli are impaired and reduced. The circadian rhythm observed in patients with intermittent claudication has early evening peaks and a nocturnal trough with a nadir occurring after midnight and before 0400. This rhythm displays marked similarities with those of all other circulatory values. As to the mechanism of rhythm, it is hard to decide whether or not it has an independent endogenous origin. It is known that many of the circulatory variables are interrelated and that some are clearly related to other circadian rhythms. Perhaps the rhythmic reduction of limb blood flow which occurs during the night is the mechanism underlying the nocturnal pain of subjects with limb ischemia by peripheral arterial disease.

Adult↗

PubMedDate not supplied

Blood viscosity and filtration abnormalities in mixed cryoglobulinemia patients.

Blood, plasma and serum viscosity and blood filtration were investigated in 43 unselected mixed cryoglobulinemia patients. A hyperviscosity syndrome was present in only one patient, and rapidly improved after plasma exchange and cyclophosphamide therapy. A clear-cut increase in blood viscosity was infrequently observed in mixed cryoglobulinemia, although significant differences were present in the plasma and serum viscosity of patients and controls. In contrast, blood filtration was severely impaired in a high percentage of cases (51 and 72% of the values recorded at 37 degrees and 25 degrees C, respectively), and was on the average significantly higher in patients than in controls. Indirect evidence suggests that blood viscosity is at least in part related to cryoglobulins. In 19 patients studied before and after cryoglobulin removal, serum viscosity significantly decreased when the serum was deprived of cryoglobulins. In addition, the cryocrit correlated with all the hemorheological parameters with the exception of blood filtration. The hemorheological findings were compared with multisystemic features of the disease, i.e. liver, renal, lung, neurologic, vascular and funduscopic alterations. The potential clinical relevance of the hemorheological parameters was stressed by the close correlation between blood filtration parameters and serum creatinine. Furthermore, by discriminant analysis, viscosity and blood filtration changes were the serological parameters most significantly associated with the presence of renal, liver and neurological involvement. Thus, hemorheological parameters are frequently abnormal in mixed cryoglobulinemia patients, and seem to play a significant clinical role; they should therefore be included in the work-up of these patients.

Adult↗

PubMedDate not supplied

[Rheology of the blood. II].

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Blood Circulation↗

PubMedDate not supplied

[Blood rheology].

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Blood Flow Velocity↗

PubMedDate not supplied

[Behavior of exercise hyperemia in normal subjects and in patients with arterial diseases].

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Adult↗