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The immediate appearance of platelets in wounds and the ability of platelets to release growth factors suggest that platelets are an important trigger of the tissue repair process. To examine the effect of systemic thrombocytopenia on both the inflammatory and proliferative aspects of wound healing, adult mice were rendered thrombocytopenic by intraperitoneal administration of a rabbit antimouse platelet serum. Full-thickness excisional dermal wounds were prepared and analyzed for inflammatory cell content, growth factor production, reepithelialization, collagen synthesis, and angiogenesis at multiple time points after injury. Compared to control mice, thrombocytopenic mice exhibited significantly altered wound inflammation. Wounds of thrombocytopenic mice contained significantly more macrophages and T cells, yet exhibited neutrophil content similar to wounds from control mice. Surprisingly, thrombocytopenic mice exhibited no delay in the reparative aspects of wound healing. The rate of wound reepithelialization, collagen synthesis, and angiogenesis was nearly identical for thrombocytopenic and control mice. Analysis of vascular endothelial growth factor, fibroblast growth factor 2, transforming growth factor beta1, keratinocyte growth factor, and epidermal growth factor revealed no difference in the levels of these growth factors in the wounds of control and thrombocytopenic mice. Taken together, the results suggest that the presence of platelets may influence wound inflammation, but that platelets do not significantly affect the proliferative aspects of repair, including wound closure, angiogenesis, and collagen synthesis.

Upon stimulation, mast cells release a heterogeneous group of factors that promote inflammation and influence cell proliferation. Mast cells accumulate at sites of injury, further suggesting a critical role in wound healing. To assess the importance of mast cells in tissue repair, we compared wound healing in mast cell-deficient WBB6F1/J-KitW/KitW-v (KitW/KitW-v) and wild type WBB6F1/++ (WT) mice. During the inflammatory phase, neutrophil infiltration into wounds of the KitW/KitW-v mice was significantly less than that of WT mice (84.6 +/- 10.3 vs. 218 +/- 26.0 cells/10 high-power fields at day 3, p < 0.001), while wound macrophage and T cell infiltration were similar in both strains. The decrease in neutrophils could not be explained by changes in tumor necrosis factor-alpha or macrophage inflammatory protein-2 levels, because the amounts of these two neutrophil chemoattractants were similar in both KitW/KitW-v and WT mice. Surprisingly, the absence of mast cells had no effect on the proliferative aspects of wound healing, including reepithelialization, collagen synthesis, and angiogenesis. Although mast cells are known to release proangiogenic mediators, vascular endothelial growth factor levels were similar in WT and KitW/KitW-v mice. Moreover, levels of fibroblast growth factor-2 were increased in KitW/KitW-v mice (4206 +/- 107 vs. 1865 +/- 249 pg/ml, p < 0.01). These results suggest that mast cells modulate the recruitment of neutrophils into sites of injury, yet indicate that mast cells are unlikely to exert a major influence on the proliferative response within healing wounds.

Mesenteric and omental cysts are rare intra-abdominal lesions. The rarity of these lesions, with an incidence of only about 1 in 140,000 hospital admissions, and the absence of characteristic clinical findings makes diagnosis difficult. Fourteen patients were treated for either mesenteric and/or omental cysts between 1965 and 1994 at Egleston Children's Hospital at Emory University. Of the 14 patients, 6 were female, 8 male; 3 were non-Caucasian, and 11 were Caucasian. They ranged in age from in-utero to 12 years old, with the most common presenting symptoms being abdominal distention (71%), pain (50%), vomiting (50%), and pain and distention (43%). Ultrasonography was the diagnostic method of choice. Other diagnostic modalities included intravenous pyelogram, barium enema, upper gastrointestinal series, CT scan, and MRI in selected patients. A single mesenteric cyst (79%) was most common, with only one patient (7%) having multiple mesenteric cysts as well as an omental cyst. The remaining two patients (14%) had single omental cysts. On gross examination, most (64%) were single, multilocular cysts. On pathological examination, the cysts ranged in size from 3.5 x 1 x 0.2 cm to 30 x 40 x 10 cm, with a mean of 14.9 x 11.5 x 4.7 cm. Six of the 14 contained fluid consistent with hemorrhage into the cysts. The most common treatment was simple excision (71%) followed by excision with partial bowel resection (29%). None received drainage alone as a treatment. There were no major postoperative complications and no reported recurrences of the cysts.