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Biomedical subjects

G Pfister

Publications and source records attributed to G Pfister.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Does caval aplanarity influence power losses across in vitro cavopulmonary connections?

Optimally designed cavopulmonary connections are desirable to reduce transanastomotic power loss. Since aplanarity of the total cavopulmonary connections results from the natural anterior-posterior position of the superior vena cava and the right pulmonary artery, the aim of this study was to investigate the influence of aplanarity of caval offset on transanastomotic power losses. Two types of cavopulmonary connections, a planar cross-like connection and a nonplanar V-shaped anastomosis, were studied in a mock circulation, comparing for each type native porcine vessels and Perspex glass models. Total flow varied between 1200 and 6000 ml/min at superior to inferior caval flow ratios of SVC/IVC = 50/50% and 33/67%, respectively. Pressures and flows were measured and power losses calculated. No significant differences in power losses were found between the planar and aplanar connections for native vessels or for Perspex glass models. Power losses across the native preparations in each configuration were significantly higher than those in the corresponding Perspex glass model. The simulation of the natural aplanar V-shaped caval offset in total cavopulmonary connections used to bypass the right ventricle seems to have no relevant additional effect on in vitro power losses compared to planar connections.

Adolescent↗
PubMedDate not supplied

Skin capillary aneurysms detected by indocyanine green in type I diabetes with and without retinal microaneurysms.

Functional diabetic microangiopathy of skin vessels is well known (decreased reactivity of arterioles to various stimuli, increased capillary pressure and permeability). In contrast to conventional capillaroscopy, recently introduced infrared fluorescence videomicroscopy with indocyanine green allows one to depict capillary aneurysms, even when filled with plasma alone. Seventeen healthy volunteers (mean age 37.7 years), 14 patients with type I diabetes without (31.3 years) and 17 with retinal microaneurysms (46.8 years) were studied. The mean duration of diabetes in patients without retinal microaneurysms was 14.2 years (4-36 years) and in those with retinal microaneurysms 21.5 years (8-49 years). Nailfold capillary aneurysms were present in 3 of 17 healthy controls, in 7 of 14 patients without and in 10 of 17 patients with retinopathy. Patients with type I diabetes with and without retinopathy exhibited significantly more skin microaneurysms (p < 0.05 and < 0.005, respectively) than the controls. The prevalence in the patients with retinal microaneurysms tended to be even higher. Skin capillary aneurysms, which may be depicted in vivo by sophisticated infrared fluorescence videomicroscopy, even when filled by plasma alone, are an important morphological feature of diabetic microangiopathy.

Adult↗
PubMedDate not supplied

Fluorescence microlymphography in chronic venous incompetence.

In severe chronic venous incompetence there is not only microangiography of the blood capillaries, but the superficial lymphatic skin capillaries at the medial ankle region are damaged also. The network visualized after subepidermal injection of FITC-dextran 150,000 is interrupted by obliterations or is even completely destroyed. In addition, lymphatic microangiopathy may be diagnosed by increased leakage of the dye out of the capillaries (enhanced permeability) and by phenomena of cutaneous reflux (parts of the network filling from deeper invisible channels). It is concluded that formation of indurated edema in chronic venous insufficiency arises at least in part from lymphatic microangiopathy.

Capillaries↗