Effects of ultrafiltration, dialysis, and temperature on gas exchange during hemodiafiltration: a laboratory experiment.

To study gas exchange in the filter during continuous venovenous hemodiafiltration (CVVHDF), an air-tight heated mixing chamber with adjustable CO2 supply was constructed and connected to a CVVHDF monitor. Bicarbonate-free crystalloid (Part 1) and packed red blood cell (Part 2) solutions were circulated at 150 ml x min(-1). Gas exchange expressed as pre-postfilter difference in CO2 and O2 contents was measured at different CVVHDF settings and temperatures of circulating and dialysis solutions. Ultrafiltration was most efficacious for CO2 removal (at 1,000 ml x h(-1) ultrafiltration CO2 losses reached 13% of prefilter CO2 content). Addition of dialysis (1,000 ml x h(-1)) increased CO2 loss to 17% and at maximal parameters (filtration 3,000 ml x h(-1), dialysis 2,500 ml x h(-1)), the loss of CO2 amounted to 35% of prefilter content. Temperature changes of circulating and/or dialysis fluids had no significant impact on CO2 losses. The O2 exchange during CVVHDF was negligible. Currently used CVVHDF is only marginally effective in CO2 removal. Higher volume ultrafiltration combined with dialysis can be expected to reach clinical significance.

[A new therapeutic approach in trophic defects of the lower extremities]. / Nový lécebný prístup u trofických defektu dolních koncetin.

The authors describe the case of a 60-year-old woman patient with a crural ulcer with a traumatic, arterial, venous and lymphatic aetiology. After three-year unsuccessful treatment by conventional methods and surgery a combination of hyperbaric oxygen therapy and plastic surgery was used. This rational therapeutic approach was very effective and the authors recommend its introduction into routine practice.

[Changes in hemostasis in persons exposed to a change in atmospheric pressure]. / Zmeny hemostázy u osob ve zmeneném atmosférickém tlaku.

In eight healthy volunteers--four professional and four amateur divers--in a hyperbaric chamber simulated diving was implemented, corresponding to the most frequently encountered conditions of diving activities in Czechoslovakia. Throughout the trial indicators of haemostasis were investigated. Under the selected model conditions changes of the investigated parameters developed which can be considered indicators of a latent process of disseminated coagulation and the so-called syndrome of silent bubbles.

[Treatment of ischemic cerebrovascular accidents with hyperbaric oxygenation]. / Lécba ischemických mozkových cévních príhod hyperbaroxií.

The authors present eleven year's experience with comprehensive treatment of patients who suffered an ischemic cerebrovascular attack. This comprises so-called conventional treatment of cerebrovascular attacks and also hyperbaroxia, i.e. administration of oxygen under high partial pressure. The authors used a therapeutic pressure of 0.2 MPa for 90 minutes in individual exposures. Of 31 treated patients 23 improved, i.e. 76%; eight improved slightly, eight significantly and seven substantially. The condition of the remainder did not change. Hyperbaroxia should therefore be used everywhere where this method is available.

Tandem scanning microscope--a new tool for three-dimensional microanatomy.

Tandem Scanning Microscope enables us to observe in real time one thin layer under the surface of a highly complex semitransparent object (e. g. living tissue), make photographs of thick layers in such objects and observe (by means of a stereoscope) three dimensional images of such objects. Important results can be obtained with moderate expenditure on basic hardware and the equipment can be expanded steadily according to the state of our budget.

Tandem scanning reflected light microscopy of internal features in whole bone and tooth samples.

An improved version of the tandem-scanning reflected-light microscope (Petran et al., 1968) has been studied with respect to its applicability to the study of mammalian mineralized tissues. It was found to have important advantages compared with other light microscopic methods, since it allowed microscopic structures to be seen at considerable depths within intact specimens. It has a small depth of focus and gives high contrast for features such as osteocyte lacunae and canaliculi in bone, and prism boundaries in dental enamel.