Extracellular matrix supports healing of transected rabbit Achilles tendon.

Extracellular matrix (ECM) has been intensively used in cardio surgery. The main goal of this research was to determine if Achilles tendon healing could be promoted by applying extracellular matrix scaffold (CorMatrix®, USA). Sixteen (n = 16) New Zealand white mature rabbits (Oryctolagus cuniculus) were randomly allocated into two groups. Following complete surgical transection, rabbits in group A (ECM applied) (n = 8) had their Achilles tendons reconstructed using both, nylon suture and extracellular matrix scaffold, whereas in group B (without ECM) the tendons were reconstructed using nylon suture only. After four weeks, the rabbits were euthanized and tendon samples harvested and stained with hematoxylin eosin, Mallory, and Gomory and subsequently histologically analyzed according to modified Bonnar scale. Group B had significantly stronger inflammatory response, including abundant cell infiltration and neovascularization. In group A collagen fibers were predominantly found, whereas in group B reticular fibers were more abundant. Extracellular matrix scaffold has been found to have the real potential for promoting tendon healing through accelerating collagen formation, which is crucial for restoring biomechanical properties of a tendon, decreasing peritendineous adhesion formation, and reducing inflammatory edema and subsequently pain.

Cardiopulmonary effects of hemorrhagic shock in splenic autotransplanted pigs: a new surgical model.

The spleen is an important organ for hemodynamic compensation during hemorrhagic shock. The aim of the study was to compare the hemodynamic and metabolic responses of sham-operated pigs with intact spleen, splenectomized pigs, and splenic autotransplanted pigs during hemorrhagic shock. Hemorrhagic shock was induced by 30% total blood volume bleed in sham-operated, splenectomized and splenic autotransplanted pigs (n = 20). Cardiopulmonary and metabolic variables were measured before, immediately after, and at 20, 60 and 100 minutes after hemorrhage. Upon hemorrhagic shock induction, body temperature, mean arterial pressure, mean pulmonary arterial pressure, cardiac output, cardiac index and oxygen delivery decreased, while lactate and shock index increased. Hemoglobin and hematocrit were significantly lower in the splenectomized and splenic autotransplant groups as compared with the control group at 60 and 100 minutes after hemorrhage (p < 0.05). Unlike intact spleen, splenic autotransplant could not improve hemodynamic parameters in hemorrhagic shock in pigs. In comparison to mice, rats or dogs, this species could be an interesting investigation model to test new surgical procedures during splenic related hemorrhagic shock, with potential applications in human medicine.

The temperature changes in the pulp chamber during cavity preparation with the Er:YAG laser using a very short pulse.

OBJECTIVE: The aim of this study was to examine the temperature changes in the pulp chamber during cavity preparation with the Er:YAG laser (2940 nm) with a very short pulse (VSP). MATERIALS AND METHODS: Nine groups of 10 intact molars each were used. One root of each sample was amputated and a thermocouple was inserted into the chamber. Class V cavity preparation in enamel was performed, and then preparation was performed in dentine. The enamel was lased with 400, 360, and 320 mJ in contact mode using a VSP with a duration of 100 microsec. The diameter of the fiber tip was 950 microm. Frequencies of 10, 12, and 15 Hz were used, and the total time of irradiation was 10 sec. The dentine was irradiated with 340, 280, and 200 mJ at 10, 8, and 5 Hz for 7 sec. Cooling was done with a water spray (73 psi and 50 mL/min). The differences were tested by MANOVA and the Bonferroni post hoc test. RESULTS: The highest rise in temperature in the pulp was achieved after enamel irradiation with 400 mJ and 15 Hz (1.99 +/- 0.28 degrees C), and the lowest was after irradiation with 320 mJ and 10 Hz (0.70 +/- 0.18 degrees C). In dentine the highest temperature increase was achieved with 340 mJ and 10 Hz (1.37 +/- 0.42 degrees C), and the lowest was with 200 mJ and 5 Hz (0.43 +/- 0.18 degrees C). Two-way analysis of both enamel and dentine showed that the influence of energy on temperature increase was stronger than that of frequency. CONCLUSION: Cavity preparation with an Er:YAG laser using VSP mode in vitro did not cause significant increases in temperature in the pulp chamber of human molars.