A rare case of rupture of the brachial artery with distal ischaemia following open elbow dislocation in a child is reported. The use of a shunting catheter successfully maintained the distal circulation until definitive brachial artery reconstruction was performed.
Section of Plastic and Reconstructive Surgery University of Michigan Ann Arbor, MI Division of Plastic and Reconstructive Surgery University of Toronto Toronto, Ontario, Canada
We have examined the distribution of centrioles in rabbit thoracic aortic endothelial cells induced to migrate by wounding the endothelium in situ. Following denudation of the endothelium from a segment of the aorta with a balloon catheter, a wound edge was created from which endothelial cells began to migrate onto the denuded surface. In this in situ model of cell migration, the position of centrioles was determined in cells along the wound edge by immunofluorescence and antibodies which specifically label these cell organelles, and then they were classified in relation to the nucleus and the direction of cell migration as being oriented toward the wound, in the center, or away from wound. At time 0, as in normal unwounded adult rabbit aorta, no preferential orientation of centrioles was evident. Within 12 h after wounding, the centrioles in about 53% of endothelial cells near the wound edge were oriented toward the wound, while in less than 20% of the cells they were oriented away from wound. At 24 h, in cells up to 800 μm from the wound edge, centrioles in only about 10% of the endothelial cells were oriented away from wound, while in about 52% of cells they were found in the center and in 38% of the cells they remained oriented toward the wound. At 48 h, up to 2000 μm from the wound edge, the majority of endothelial cells had their centrioles in the center, possibly as a result of an increase in mitotic index as cells replicate to reestablish an intact endothelium. The results of this study demonstrate that, in endothelial cells starting to migrate on a natural substratum in situ in response to wounding, most centrioles reorient toward the wound edge. This observation is consistent with the hypothesis that the centrosome is involved in defining the direction of cell migration in endothelial cells.Key words: centriole, in situ, endothelium, wound healing, aorta.
The distribution of centrioles was examined in porcine and rabbit vascular endothelial cells fixed in situ and prepared en face for immunofluorescent staining with rabbit sera that specifically stain these organelles. In endothelial cells lining the major blood vessels of the pig, the centrioles are preferentially located on the heart side of the nucleus regardless of the direction of blood flow. A similar distribution is seen in the inferior vena cava of the rabbit but not in the rabbit aorta. In the major vessels of the pig and in the rabbit inferior vena cava, 60%-80% of the endothelial cells have their centrioles located on the side of the nucleus toward the heart, 10%-20% have them on the side away from the heart, and 7%-15% have them in a central position along the side of the nucleus. To determine whether this preferential orientation is reestablished, microvascular surgical techniques were used to reverse a 3-cm segment of the inferior vena cava between the left renal vein and the common iliac veins of the rabbit. Within 1 week of the reversal, some of the centrioles had migrated from the end away from the heart to a more central position. During the following weeks, an increasing number of endothelial cells had their centrioles located on the heart side of the nucleus; after 12 weeks, values similar to those in the nonreversed inferior vena cava were reached in the reversed segment. The demonstration that the preferential orientation of centrioles on the heart side of the nucleus is reestablished after reversal of a segment suggests that the observed polarity is important for normal functioning of vascular endothelium.
The effects of increased functional loading on early cellular regenerative events after exercise-induced injury in adult skeletal muscle were examined with the use of in vivo labeling of replicating myofiber nuclei and immunocyto- and histochemical techniques. Satellite cell proliferation in the soleus (Sol) of nonexercised rats (0.4 ± 0.2% of fibers) was unchanged after an initial bout of declined treadmill exercise but was elevated after two (1.0 ± 0.2%, P ≤ 0.01), but not four or seven, daily bouts of the same task. Myonuclei produced over the 7-day period comprised 0.9–1.9% of myonuclei in isolated fibers of Sol, tibialis anterior, and vastus intermedius of nonexercised rats. The accretion of new myonuclei was enhanced ( P ≤ 0.05) in Sol and vastus intermedius by the initial exercise followed by normal activity (to 3.1–3.4% of myonuclei) and more so by continued daily exercise (4.2–5.3%). Observed coincident with a lower incidence of histological fiber injury and unchanged fiber diameter and myonuclei per millimeter, the greater new myonuclear accretion induced by continued muscle loading may contribute to an enhanced fiber repair and regeneration after exercise-induced injury.
Replantation of a penis with microsurgical repair of vessels and nerves can restore normal genitourinary function. A case is presented of an amputated penis that was ischemic for sixteen hours before being microsurgically revascularized. The patient has at all times appreciated having an intact penis despite the fact that the injury was self-inflicted. Self-mutilation is not considered to be an absolute contraindication to replantation
