[Cryopreservation of human erythrocytes with hydroxyethyl starch (HES)--Part 2: Analysis of survival]. / Kryokonservierung von Human-erythrozyten mit Hydroxyethylstärke (HES)--Teil 2: Vitalitätsanalytik.

Red blood cells (RBC) were obtained from 5 whole blood units by centrifugation and were purified using a simple washing procedure. Hematocrit and HES concentration in the 108-ml samples to be frozen were adjusted to 40% (v/v) and 12% (w/w), respectively. Cooling was performed by submerging into liquid nitrogen using containers to generate a flat sample geometry (3 mm thickness). After thawing in a shaking water bath, HES and free hemoglobin were removed in a simple washing step. To investigate the influence of the resuspension medium, the RBC were transferred into freshly drawn autologous plasma and into Locke's solution. Survival after thawing in terms of saline stability reached 86.3 +/- 2.3%. The cryopreservation procedure caused no major changes with regard to osmotic fragility, 2,3-DPG or intracellular Na+ and K+. ATP was reduced by 16%, but this had completely recovered after 3 h resuspension in autologous plasma. Some morphological changes present after thawing (e.g. stomatocytes, echinocytes) also recovered after 1.5 h. In conclusion, those RBC which survived the preservation process can be considered to be fully viable with regard to the parameters investigated.

[Cryopreservation of erythrocytes with hydroxyethyl starch. In vitro results leading to an autologous retransfusion model in the dog]. / Kryokonservierung von Erythrozyten mit Hydroxyethylstärke (HES). In-vitro-Ergebnisse auf dem Weg zum autologen Retransfusionsmodell beim Hund.

Although the effectiveness of hydroxyethyl starch (HES) as a cryoprotectant for human red blood cells (HRBC) is well known, no clinical application has evolved so far. In contrast to glycerol HES has the advantage of causing no hemolysis per se. This offers the opportunity of a one-step procedure without a time consuming postthaw washing procedure prior to transfusion. In this study the in vitro results obtained with red blood cells from 8 dogs (DRBC) are reported and compared to HRBC (n = 5). It turned out that DRBC had a similar 2,3-DPG and a lower ATP content. Postthaw survival in terms of saline stability differed markedly (67 +/- 6 and 86 +/- 2%, respectively). DRBC were more susceptible to hypotonic stress than HRBC. Nevertheless, after cryopreservation 91% (HRBC) and 92% (DRBC) of the original 2,3-DPG were found in the thawed RBC concentrates.

[Morphological changes after permanent nerve block by freezing and ethanol injection of the sciatic nerve of the rabbit (author's transl)]. / Vergleichende histologische Untersuchungen am Nervus ischiadicus des Kaninchens nach Blockade der Nervenleitung durch Vereisung oder Alkoholinjektion.

Permanent nerve blocks by intraneurally injected alcohol are often complicated by alcohol-neuritis. Encouraging clinical experiences with permanent blocks by freezing raises the question whether morphological differences between the nerve lesions could explain the difference in their side effects. On 30 rabbits both sciatic nerves were blocked after surgical preparation. The one by intraneural injection of 0,5 ml of 96% Ethanol, the other by freezing with a cryoprobe. The resulting degeneration and the beginning of recovery of the nerves was followed by histological evaluations of the sciatic nerves during the first 28 days after the blockade. The nerve lesions of both types of blockade were complete. That produced by the cryoprobe was limited to the small area of local freezing, whereas the alcohol-block produced the same type of nerve degeneration but with a wide-spread extension reaching the sacral plexus. We discuss whether this slight morphological difference might be sufficient to explain the higher complication rate of alcohol blocks.

[Arguments for suturing of a gap in the flexor tendons of fingers]. / Argumente für die Naht der Beugesehnen der Finger im Niemandsland.

1. Tendon healing may originate from the vascularized epitenon of the tendon stumps. 2. This is dependent upon the gap between the tendon stumps being rather small. 3. In tendon sutures after Kessler the gap averaged only 2.5 mm, whereas the average after Bunnell suture was 6.7 mm and after Lengemann suture, 9.8 mm. 4. After isolated division of the deep flexor tendon (80% of cases) and division of both flexor tendons (65%), good results with a distance = 2.5 cm between the nail and the distal palmar crease could be obtained.

[Direct flexor tendon suture in the digital sheath]. / Zur direkten Beugesehnennaht im Sehnenscheidenbereich der Finger.

From 1976 to 1976 in 44 fingers (41 patients) flexor tendons within the digital sheath (zone I and II) were repaired by direct suture. A modification of KESSLER's "grasping" suture was employed. In 21 fingers only the deep flexor and in 23 fingers both flexor tendons were divided; in these cases a repair of both tendons was carried out whenever possible. In cases of delayed repair, however, secondary changes of the gliding apparatus often prevented a repair of the superficialis tendon. Tenolysis was proposed in one half of the cases. It was done not earlier than 3 months after tendon suture. After division of both flexor tendons we obtained in cases with good preoperative conditions (21 fingers) 66% of good and excellent results, according to BOYES' classification, and 75% according to BUCK-GRAMCKO's classification.

[A new technic for the correction of malunited distal radius fractures]. / Neue Technik zur Korrektur in Fehlstellung verheilter distaler Radiusfrakturen.

After malunited fractures of the distal radius the original anatomy of the wrist joint can be restored only by osteotomy of the radius and interposition of a cortico-cancellous bone block. This procedure has been shown to be much easier using a new bone plate for internal fixation. The plate is applied to the radius volarly through a radio-volar approach. The correcting angles can be adjusted easily. The stable osteosynthesis allows early postoperative motion. In cases of osteoarthritic changes the procedure may be combined with a denervation of the wrist joint (A. WILHELM).