Emergent reuse leech therapy: a better method.

Tissues threatened by venous congestion often can be saved by timely leech therapy. Methods to restimulate sated leeches, particularly emergently, are only poorly described in the nineteenth-century literature. Sated leeches were purged of their blood meals by (1) posterior crop incision, (2) hypertonic saline (3 percent) immersion, (3) gentle finger pressure emesis, or (4) wood ash exposure. Their ability to reattach and refeed with or without serotonin stimulation was evaluated. All 20 leeches (100 percent) purged by posterior crop incision reattached, with 75 percent refeeding. After purging again, 87 percent of these refed leeches reattached, with 46 percent refeeding for a third time. Those leeches which did not initially refeed were exposed to serotonin 10 microM with 100 percent reattaching and 40 percent refeeding. None of the leeches purged by hypertonic saline immersion regurgitation reattached or refed. A single leech purged by finger pressure emesis reattached (20 percent) but did not refeed. After exposure to serotonin, two (40 percent) of each saline and finger pressure group reattached, with neither of the hypertonic saline group refeeding, while both finger pressure-purged leeches refed, consuming a meal 38 percent (+/- 29 percent) of original meal. None of those leeches which refed would reattach or refeed a third time. None of the wood ash-purged leeches reattached or refed even with serotonin exposure. The best method of purging leeches of their blood meals for emergent reuse is by posterior crop incision. Additional refeeding behavior can be achieved by immersion in serotonin 10 microM for 20 minutes.

Ultrasound debridement of trabeculated bone: effective and atraumatic.

Given the plethora of techniques available for debridement of contaminated bone, no single method can be considered ideal. Ultrasound has been shown to be less traumatic and more effective for debridement of contaminated soft tissue than either abrasive scrubbing or high-pressure jet irrigation. Using the distal femur and condyle of 23 freshly sacrificed adult Sprague-Dawley rats, this study was undertaken to compare ultrasonication to traditional debridement techniques in (1) their effectiveness in decontaminating trabeculated bone, (2) the subsequent effect of each treatment on bone cell function as measured by protein synthesis, and (3) the direct mechanical effects of each technique on the integrity of the bone structure itself. Ultrasonic debridement was found to be as effective as high-pressure jet irrigation or surgical scrubbing in debridement of contaminated trabeculated bone (no significant statistical difference). Overall activated bone cell function 24 hours after each debridement technique also was found to be equivalent (no significant statistical difference). However, electron microscopy reveals radical structural alterations of the bone after high-pressure jet irrigation or abrasive scrubbing that are not seen with ultrasound debridement. Acutely, the devastating effects of abrasive scrubbing and high-pressure jet irrigation leave an exposed bone matrix not only devoid of any cells but also honeycombed with interstices for entrapment of bacteria and other contaminants. All three debridement methods leave the deeper bone cells viable, but only ultrasound maintains the integrity of the directly involved bone trabeculum to reduce contamination, prevent colonization, and decrease possible infection.

Medial edge epithelium fate traced by cell lineage analysis during epithelial-mesenchymal transformation in vivo.

Vital cell labeling techniques were used to trace the fate of the medial edge epithelial (MEE) cells during palatal fusion in vivo. Mouse palatal tissues were labeled in utero with DiI. The fetuses continued to develop in utero and tissues of the secondary palate were examined at several later stages of palatal ontogeny. The presence and distribution of DiI was correlated with the presence of cell phenotype-specific markers. During the initial stages of palatal fusion the DiI-labeled MEE were present in the midline position. These cells were attached to an intact laminin-containing basement membrane and contained keratin intermediate filaments. At later stages of palatogenesis the DiI-labeled MEE were not separated from the mesenchyme by an intact basement membrane and did not contain keratin. In late fetal development, DiI-labeled cells without an epithelial morphology were present in the mesenchyme. The transition of the DiI-labeled cells from an epithelial phenotype to a mesenchymal phenotype is consistent with a fate of epithelial-mesenchymal transformation rather than programmed cell death.

Assessment of acute microcirculatory changes by color Doppler sonography.

We studied the efficacy of color Doppler sonography in the transcutaneous assessment of acute changes in microvascular flow. Arterial and venous occlusion studies were performed in rabbits after simple isolation of the common femoral artery and vein and after raising an epigastric island flap. Vessel diameters were measured through an operating microscope and compared to color Doppler determinations of the diameters. Vessel patency and blood flow in the major vessels were monitored before and after occlusion. The correlation of vessel diameters measured under the operating microscope and with color Doppler sonography was .91 for the arteries and .39 for the veins. A strong linear correlation existed between Doppler identification of arterial occlusion, but not of venous occlusion. This study demonstrated that color Doppler sonography can be used transcutaneously to reliably assess patency and blood flow in the small vessels. Time-dependent, reproducible patterns in the spectral waveform analysis were indicative of the onset of arterial or venous occlusion.