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Biomedical subjects

G Pfister

Publications and source records attributed to G Pfister.

At least 37 records · Page 2Linked to original sources
PubMed1995

A new experimental model and formula for flow determination and possible application in sizing of interatrial communication.

The concept of an artificial interatrial communication in application of the Fontan procedure in high risk patients has raised the problem to exactly determine the shunt amount. This experimental study shows that in vitro flow studies of interatrial communications can be performed without animal blood and PTFE membranes respectively. Furthermore the simulation of an pulmonary vascular venous flow is not necessary. Additionally a new formula with acceptable accuracy for flow estimation is derived from the presented data obtained by this study.

Animals↗
PubMed1991

[Microangiopathy in chronic venous insufficiency].

Skin in the medial malleolar region was examined in 15 patients with moderately severe venous insufficiency (9 women, 6 men; mean age 57 [35-76] years), using intravital fluorescence microscopy, transcutaneous pO2 measurement and laser Doppler flowmetry. The findings were compared with those in a healthy control group (8 women, 7 men; mean age 53 [35-73] years). The arteriolar vasoconstriction response was tested by comparing laser Doppler flowmetry readings in the recumbent and sitting positions. Transcutaneous pO2 was likewise measured in both positions. Capillary morphology and microangiodynamics were investigated before and after injection of Na-fluorescein. The microangiopathy of moderately severe venous insufficiency was characterised fluorescence microscopically by greatly dilated, elongated and winding (glomerulus-like) capillaries, and by an increase in the pericapillary leakage diameter (halo). However, the vasoconstrictive response to change in posture remained largely intact, and there was little alteration in the spontaneous rhythmic flow waves. In contrast, flow in the recumbent position was significantly increased (P less than 0.001), since laser Doppler flowmetry also measures the flow in deeper (1-6 mm), non-nutrient skin vessels. In spite of a normal capillary count, the mean transcutaneous pO2 was reduced, in keeping with the microangiopathy observed in the superficial nutrient capillaries. These pronounced morphological and dynamic changes explain the development of trophic lesions.

Adult↗
PubMed1990

Diameters of lymphatic capillaries in patients with different forms of primary lymphedema.

Fluorescence microlymphography was performed near the medial ankle in 12 healthy controls, 12 patients with congenital and 12 with sporadic lymphedema of the lower extremities. Diameters of lymphatic capillaries were determined on the videoscreen by playback of the tape recordings using a morphometric technique. In the patients with congenital disease (Nonne-Milroy) aplasia of microlymphatics was diagnosed in 8 instances, ectasia in 4. Patients with sporadic lymphedema and manifestation after puberty exhibited initial lymphatics of normal caliber. In controls mean capillary diameter was 56.3 +/- 9.0 microns, in congenital disease with ectasia 99.3 +/- 9.0 microns (difference significant at the p less than 0.005 level) and in the sporadic form 49.7 +/- 7.7 microns. Congenital lymphedema may be subdivided into a form with aplastic and ectatic microvessels which possibly show different responses to therapy.

Adolescent↗
PubMed1987

[Comparison of the efficacy and tolerance of Kabi 2165 and standard heparin in the prevention of deep venous thrombosis in total hip prosthesis].

A series of 80 patients operated for total hip prosthesis under epidural anesthesia was randomly allocated to treatment with Kabi 2165 (n = 40): 2,500 U anti-Xa preoperatively and evening of operation and 2,500 U anti-Xa morning and evening daily up to the 9th or 10th day postoperatively, or standard heparin (n = 40): 3,750 U preoperatively and then 8 hourly, at a dose adjusted with thrombin time and cephalin + activator time, daily up to the 9th or 10th day. Phlebography was performed routinely on the 9th or 10th day. Venous thrombosis occurred in 7 patients (17.5%) in the Kabi 2165 group, including two high, potentially emboligenic, localizations (5%), and in 4 patients (10%) in the standard heparin group, including 2 potentially emboligenic clots (5%). The difference is not statistically significant (total number: p = 0.5; potentially emboligenic: p = 0.33). Pulmonary embolism did not occur. Overall tolerance, evaluated from hemoglobin and hematocrit values, intra- and post-operative bleeding and operation wound hematoma and at injection site was comparable in the two groups.

Aged↗
PubMed1985

A comparative study on pesticide formulations for application in running waters.

Release rates into water of monolinuron, desmetryne, and carbofuran from three different types of formulations have been studied to control aquatic weeds in running waters. The migration of active ingredients (AI) from conventional wettable powder formulations was complete within 1 day, while the migration from ethylene-vinyl acetate copolymeric matrix (EVA) lasted significantly longer due to low diffusion coefficients of monomeric pesticides in polymeric matrices Do = 10(-8)-10(-12) (cm2 X sec-1). The herbicidal action could be extrapolated up to several years. Release duration of AI from calcium alginate beads lasted 2 weeks. Herbicidal effectiveness of terbutryne-EVA formulation has been investigated in a laboratory-scale simulated flow system device with duckweed plants (Lemna minor) as test organism. Growth inhibition of duckweed could be achieved at approx 20 ppb terbutryne in steady state.

Absorption↗