Red cell aggregation and the echogenicity of whole blood.

To study the relationship between red cell aggregation and whole blood echogenicity, red cell aggregation was quantitated by a photometric method, whole blood echogenicity was quantitated by videodensitometry and sedimentation rate was quantitated by a modified Westergren method. Changes in red cell aggregation were produced by alterations in the hematocrit. The results showed that red cell aggregation increased in a linear fashion with increases in hematocrit. The sedimentation rate decreased in a linear manner with increases in hematocrit. Whole blood echogenicity showed a biphasic response, with an initial increase in echogenicity, peaking at hematocrits varying from 14-24% and decreasing thereafter. Over the physiologic range of hematocrits, an increase in the formation of red cell aggregates is associated with a decrease in the echogenicity of whole blood. Thus, red cell aggregates were not visible using our ultrasound equipment at physiologic hematocrits, and the echo contrast in blood under our experimental conditions at these hematocrits must represent either plasma spaces, platelet aggregates or possibly white cell aggregates. The association between spontaneous contrast and a propensity for thromboembolism imply that platelet aggregates are the most likely origin of in vivo echo contrast in flowing blood.

A computerized analysis of platelet aggregation detected by ultrasound.

The purpose of this study was to determine if computerized image processing could be used to characterize platelet aggregation visualized by ultrasound. Citrated whole blood (WB) or platelet-rich plasma (PRP) was imaged with a 12 mHz transducer before and after the addition of adenosine diphosphate. The images were digitized using a 512 x 512 pixel resolution with 256 levels of gray. Raster interference was eliminated by filtering and aggregates were separated from background by gray level discrimination. The results showed that platelet aggregation in PRP can be described by the number of aggregates counted, their sizes or their gray levels. However, aggregation in WB can be detected only by the sizes or gray levels of the aggregates due to the greater echogenicity of ex vivo WB. This methodology, applied to ultrasonic images of brachial arteries and veins, demonstrates that venous particles are common in patients and normal controls, but arterial particles are more common in patients. Differences in the size and brightness of these particles may have prognostic implications.

Identification and characterization of a proteoglycan in embryonic chicken skin that can interact with hyaluronic acid.

Sulfated proteoglycans of the dorsal skin of 8.5-day-old chick embryos have been characterized in terms of their extractability from the tissue, solubility, and sedimentation and chromatographic behavior. The proteoglycans described in this communication are those that remain soluble after dialysis against 0.5 m NaCl. Two chondroitin sulfate proteoglycans (PGCS-A and PGCS-C) and a heparan sulfate proteoglycan (PGHS) have been identified. PGCS-A is the only proteoglycan found in the medium in which the skins were cultured. Under associative conditions (0.4 M guanidine-HCl) PGCS-A and PGHS are extracted. The dissociative solvents (4 M guanidine-HCl) extract more PGCS-A and PGCS-C. PGCS-C has been shown to interact with hyaluronic acid to form aggregates. These proteoglycans have densities ranging from 1.49 to at least 1.59 g/ml. In contrast cartilage proteoglycans that can aggregate with hyaluronic acid have a density of at least 1.59 g/ml. It was not possible to determine if the PGCS-C aggregates exist in vivo.

[Scalpel and CO2 laser in the animal experiment. A comparative study of inoculation tumors of the mouse]. / Skalpell und CO2-Laser im Tierexperiment. Eine Vergleichsstudie an Impftumoren der Maus.

The study hereby submitted has been designed to show whether there are any differences between using a conventional knife or a CO2-laser when excising and grafting tumors in animal experiments. The animals were C57Bl/6 mice, the tumor was the Lewis lung carcinoma. Eight days after tumor inoculation into the subcutaneous layer of the back, 213 mice were treated by tumor excision either with a conventional knife or a CO2-laser. 86 excised tumors were cut and the tumor surface was swabbed into the subcutaneous layer on the nape of 86 tumor-free mice. Survival times of the laser-operated animals were insignificantly longer. However, small tumors showed markedly longer survival times. The interval without recurrence was longer for all tumor sizes when the laser was used (p less than 0.005). The laser method yielded lower growth rates when the tumor surface was swabbed into tumor-free mice (p less than 0.0001). Histological and cytological tests of the laser-excised and -swabbed specimen demonstrated a high rate of cell destruction. Therefore, the CO2-laser seems to have some importance in cases where the incision is made close to the tumor or where the tumor surface may be lesioned.

[Experiences with a non-inflammable tube in laser surgery of the larynx]. / Erfahrungen mit einem unbrennbaren Tubus in der Laserchirurgie des Kehlkopfes.

With the recently developed noncombustible copper-tube dangerous damages caused by tube-ignition in the larynx will certainly be avoided.

[Experimental studies of the danger of ignition of tubes during endolaryngeal microsurgery with the laser]. / Experimentelle Untersuchungen zur Ignitionsgefahr von Tuben bei endolaryngealer Mikrochirurgie mit dem Laser.

Experiments on the ignition-risk of tubes used during endolaryngeal laser surgery are reported. The mechanism of the laser as an ignition source is explained. The materials were tested as to their inflammability.

[Is the CO2 laser surgery advantageous? A morphological and experimental study (author's transl)]. / Bringt der CO2-Laserschnitt Vorteile? Morphologische und experimentelle Untersuchungen.

The great advantages of CO2 laser surgery are the contact-less cutting and the haemostatic effect. An obliteration of blood- and lymph-vessels thus preventing tumour-cell mobilisation and metastatic spread is considered as most advantageous for tumour surgery. Basing on own morphological and experimental investigations, some of these advantages are critically discussed. The morphology of human skin incisions made by a CO2 laser is described, using light microscopy, and the wound healing process of laser incisions in the dorsal skin of rats is compared with incisions made by thermocautery and conventional scalpel. After contamination of laser and scalpel incisions with india-ink, the migration of these particles to the regional lymph-nodes was also investigated. Compared to the scalpel-incisions, the laser- and even more the thermocauter-incisions showed the well known delay in healing, due to the extensive tissue necrosis at the wound margins. This coagulation necrosis, however, was not obliterate the lymphatic drainage. It is concluded from these experiments that the use of the CO2 laser will not guarantee the prevention of metastatic spread and should mainly be recommended where the haemostatic effect is essential.