Effects of interleukin-8 on granulation tissue maturation.

The inflammatory alpha-chemokine, interleukin-8 (IL-8), affects the function and recruitment of various inflammatory cells, fibroblasts, and keratinocytes. Gap junctions are anatomical channels that facilitate the direct passage of small molecules between cells. The hypothesis is that IL-8 enhances gap junctional intercellular communication (GJIC) between fibroblasts in granulation tissue, which increases the rate of granulation tissue maturation. In vitro, human dermal fibroblasts were incubated with IL-8 prior to scrape loading, a technique that quantifies GJIC. Polyvinyl alcohol (PVA) sponges were implanted within subcutaneous pockets in rats and received local injections of either IL-8 or saline and were harvested on day 11. In vitro, IL-8 treated fibroblasts demonstrated an increase in GJIC by scrape loading compared to saline treated controls. In vivo, IL-8 treated PVA sponges demonstrated a decrease in cell density and an increase in vascularization compared to saline controls by H&E staining. Polarized light viewed Sirius red-stained specimens demonstrated greater collagen birefringence intensity, indicating thicker, more-mature collagen fibers. IL-8 increases GJIC in cultured fibroblasts and induces a more rapid maturation of granulation tissue.

Wound healing: the role of gap junctional communication in rat granulation tissue maturation.

Granulation tissue maturation is dependent upon the orientation of collagen fibers and cell differentiation. Gap junctions are intercellular membrane gated channels that facilitate direct communication between cells known as gap junctional intercellular communication (GJIC). The hypothesis is that GJIC modulates the maturation of granulation tissue during wound repair. In vitro, GJIC optimizes fibroblast-populated collagen lattice contraction and influences cell morphology. It is reported that LiCl increases GJIC in cultured cardiac myocytes. Polyvinyl alcohol (PVA) sponge implants with central reservoirs were placed within separate subcutaneous pockets on the backs of adult male Sprague-Dawley rats. Each PVA implant received either 20 mM LiCl or saline injections on days 5, 7, and 10 after implantation. On day 11 implants were harvested and processed for light microscopy. By H&E staining LiCl-treated implants showed increased vascularization and decreased cell density compared to saline controls. Polarized light microscopy of Sirius red-stained specimens revealed more intense collagen fiber birefringence secondary to dense, parallel-organized collagen fiber bundles after LiCl treatment. This suggests that LiCl enhancement of GJIC between fibroblasts advances the maturation of granulation tissue. It is proposed that the degree of GJIC between granulation tissue fibroblasts influences both the quantity and the quality of granulation tissue deposited during the wound healing process.

Video microsurgery: evaluation of standard laparoscopic equipment for the practice of microsurgery.

Traditional microsurgery involves the use of bulky and expensive stereo microscopes that have limited portability. Recent advances in video technology have enabled the exploration of alternative visualization methods. The purpose of this study was to evaluate standard laparoscopic equipment for microvascular anastomoses. Eight surgeons completed anastomoses on rat femoral and synthetic vessels using stereo microsurgery and video microsurgery visualization systems. All surgeons had previous experience with stereo microsurgery and none had ever used video microsurgery. Data were collected on overall anastomosis and individual suture times. A sample of completed anastomoses was placed in a video database and evaluated by use of a quality rating scale (8 to 10, excellent; 6 to 7, adequate; less than 6, poor). All surgeons subjectively evaluated the video microsurgery system. A total of 48 anastomoses were completed. The average total anastomosis time for the stereo microsurgery was 1018.9 +/- 463.2 seconds versus 1738.9 +/- 460.1 seconds for the video microsurgery. The average individual suture placement time was 114.6 +/- 60.6 seconds for the stereo microsurgery versus 211.7 +/- 128.4 seconds for the video microsurgery (p < 0.05). Twenty-five of the anastomoses underwent quality review. The overall score of the stereo microsurgery group was 8.1 +/- 1.7, and the video microsurgery group had an overall score of 7.3 +/- 1.6. Survey results revealed that 75 percent of the participants thought that the video microsurgery would be useful for human operations and would improve surgeon comfort, but 87.5 percent would not use the present video microsurgery system over stereo microsurgery in their practice. Although significant differences exist in overall anastomosis and individual suture completion times, no difference was found in the overall quality. Video microsurgery could become a useful tool on the basis of surgeon ergonomics; however, optical parameters require further refinement.

Methylation of histone H3 by coactivator-associated arginine methyltransferase 1.

The preferential in vitro methylation of histone H3 by coactivator-associated arginine methyltransferase 1 (CARM1) has been proposed as a basis for its ability to enhance gene transcription [Chen, D., et al. (1999) Science 284, 2174-2177]. To further evaluate the significance of H3 methylation, we studied the kinetics and site specificity of its modification by CARM1. Affinity-purified CARM1 methylated recombinant chick H3, which is free of posttranslational modifications, and calf thymus H3, which is heterogeneous with regard to preexisting modifications, equally well, exhibiting a V(max) of 4500 pmol min(-1) (mg of enzyme)(-1) and an apparent K(m) for H3 of < or = 0.2 microM. The catalytic efficiency (k(cat)/K(m)) of CARM1 toward H3 was at least 1000 times that toward R1 (GGFGGRGGFGG-amide), a highly effective substrate for protein arginine methyltransferase 1. Peptide mapping of 3H-methyl-labeled H3 indicated methylation at Arg-2, Arg-17, and Arg-26 in the N-terminal region and at one or more of four arginines (128/129/131/134) at the C-terminus. Two of the N-terminal sites, Arg-17 and Arg-26, occur in the sequence KAXRK and appear to be more efficiently methylated than Arg-2. CARM1 catalyzed formation of N(G),N(G)-dimethylarginine (asymmetric) but little or no N(G),N'(G)-dimethylarginine (symmetric) and no form of methyllysine. Amino acid analysis of untreated calf thymus H3 revealed that 3.7% of the molecules naturally contain asymmetric dimethylarginine and/or monomethylarginine. Our findings support the hypothesis that methylation of H3 may be involved in the mechanism of transcriptional coactivation by CARM1 of genes whose expression is under the control of nuclear receptors.

Vanadate ingestion increases the gain in wound breaking strength and leads to better organized collagen fibers in rats during healing.

Repair of incision wounds closed by suturing is evaluated by the progressive gain in wound breaking strength. Previously the closure of open wounds in rats ingesting vanadate, an inhibitor of tyrosine phosphate phosphatases, was shown to occur with deposition of more uniformly organized collagen fiber bundles. The hypothesis of this study was that deposition of more uniformly organized collagen fibers would enhance the gain in wound breaking strength of incisional wounds. Six adult rats received vanadate-supplemented saline drinking water for 1 week before placement of two 6-cm, parallel, suture-closed wounds on their backs. Six control rats received identical wounds and were given saline drinking water. The drinking water regimen was continued for 1 week after wounding, and then wound strength was tested with a tensiometer and tissue samples were obtained for histologic evaluation. Wound breaking strength doubled in vanadate-treated rats compared with controls. Bright-field and polarized light microscopy showed that the connective tissue matrix of granulation tissue from control rats was oriented perpendicular to the surface of the skin. In contrast, the connective tissue matrix of granulation tissue from vanadate-treated rats was oriented parallel to the skin surface. The gap in granulation tissue between the edges of the wounds in the vanadate-treated rats was greater than that in controls. Electron microscopy showed that wounds in the vanadate-treated contained uniform collagen fibers that were 20 percent greater in diameter and more evenly spaced than they were in controls. It is proposed that these changes in the organization of collagen fibers within incisional wounds were responsible for the increased wound breaking strength observed in rats ingesting vanadate.

Replantation of the midfoot in a child--six-year follow-up with pedobarographic analysis.

A 22-month old child underwent successful replantation of her midfoot at the level of Chopart's joint after a traumatic lawn mower amputation. The child demonstrated good sensation and function. Heel-to-toe length was 2 cm shorter, along with anterior migration of the heel pad on the injured foot. Pedobarographic analysis at 6-year follow-up demonstrated a normal range in the dynamic distribution of foot pressure measurements, except in the region of the medial heel. With replantation more commonly considered as an option in traumatic injuries, long-term functional evaluation is important in demonstrating the success of a replantation. The patient demonstrated a good result at 6-year follow-up, but will need further evaluation until skeletal maturity is reached.

A comparison of gradual distraction techniques for modification of the midface in growing sheep.

The authors carried out experiments to advance the midface in growing sheep using a distraction force across the zygomaticomaxillary sutures. They wished to assess the possibility of performing distraction osteogenesis across intact sutures as well as distraction after Le Fort osteotomies. Their results demonstrate that the technique of gradual distraction after osteotomy is successful in the growing animal. Bilateral distraction across intact sutures did not advance the midface or change the dental relationship. Unilateral distraction was successful in angulating the midface away from the distracting force in the intact growing animal. Alternating unilateral distraction or "waltzing" was surprisingly effective in advancing the midface in one of the animals studied and may become applicable in some craniofacial deformities. In all intact animals there was some expansion of the zygomaticomaxillary suture as well as a substantial migration of the distraction devices through the bone.

Effects of topical nitroglycerin and flurbiprofen in the rat comb burn model.

Burn injury is known to cause thrombosis and occlusion of dermal vessels that come in direct contact with thermal energy. Progressive ischemia secondary to diminished blood flow may compromise dermal tissues immediately surrounding the primary burn site. A standardized brass bar was used to create uniform full-thickness "comb" burns on 10 rat backs. Topical petrolatum (N = 2), 2% nitroglycerin (N = 4), and 5% flurbiprofen (N = 4) was applied to the burns at 2 and 4 hours postinjury. The vascular patency of dermal vessels was visualized directly by latex vascular casts made 24 hours after the burn injury. The vascular casts showed an absence of patent vessels within the direct burn sites in all treatment groups, and within the burn interspaces of the petrolatum-treated rats. Interspacial dermal vessel patency was seen in the 2% nitroglycerin and 5% flurbiprofen-treated rats. Topical 2% nitroglycerin and 5% flurbiprofen applied 2 and 4 hours postinjury effectively prevented interspacial dermal vessel thrombosis at 24 hours postinjury.

SHAFT syndrome revisited.

Wallace aptly described patients with overriding psychological problems and upper extremity complaints as possessing the Shaft syndrome. SHAFT patients studied fell into two categories. The first group inflicted physical harm on themselves, creating factitious injuries. The second group postured their limbs in attitudes that are not explainable anatomically. This latter group is described by Simmons as the clenched fist syndrome. Although patients who had factitious injuries invariably healed with protective casting, 4 patients relapsed. Eight of 14 patients who were employed at the onset of their complaints returned to gainful employment. Some patients received psychological counseling but most lacked sufficient insight to make gainful progress. Reaching a diagnoses was often difficult. At least 5 patients had unwarranted operations. The surgeon needs a high index of suspicion when the history and findings do not match for patients harboring complaints of pain, numbness, stiffness, or inability to use their limb.

Aeromonas species isolated from medicinal leeches.

Aeromonas hydrophila infections are a recognized complication of the use of medicinal leeches. The authors performed an experiment designed to find a safe and practical way to sterilize the leech gut of pathogenic organisms. Leeches were incubated for a 12-hour period in solutions of antibiotic effective against A. hydrophila. The incubations in the antibiotic solutions failed to eradicate pathogenic bacteria from the gut of the leeches. The authors examined cultures of bacteria isolated from the guts of the commonly used Hirudo medicinalis (European leech) and found a wide variety of pathogenic organisms. A. hydrophila is widely believed to be the most common enteric pathogen, but the authors found A. sobria more frequently in their experiment. They also cultured the guts of the leech H. michaelseni recently used clinically in South Africa. A. caviae was the most common pathogen encountered in these leeches. A. caviae and A. sobria cause a spectra of disease similar to A. hydrophila. The authors endorse the current recommendation that all patients who have leech therapy for congested flaps or replants receive broad-spectrum prophylactic antibiotics. This appears to be the safest and simplest way to prevent leech-related infections.

Assessing the role of presuturing on wound closure.

The efficacy of presuturing was tested by quantitating the tissue gains for standardized wounds in a white swine piglet (9 to 11-kg) model. Also measured were the changes in wound closure tension for the wounds. Measurements were carried out at 1, 4, 17, 24, 48, and 72 hours in a total of 20 piglets. Presuturing was carried out on one of the flanks and the opposite flank served as the control. Presuturing achieved a modest tissue gain, amounting to 67 mm at 4 hours and a maximum of 1.4 cm at 48 and 72 hours, for a 4-cm defect. The encouraging tissue gain was unfortunately not paralleled by a decrease in the tension required to approximate the wound edges. At 4 hours, the tension to close the wound was 1.2 N (only 120 g) less than the control wound. This initial small reduction in wound-closing tension was diminished thereafter, and at 72 hours the wounds were stiffer and harder to close than the control. This appeared to be due to tissue edema and was confirmed by an increase in measurable tissue water with increasing time. In this model, presuturing produces a minimal tissue advancement and even less reduction in wound-closing tension. It is concluded, from this work and from previously published work, that undermining will prove generally to be a more useful technique in closing broad defects.

An unusual foreign body in the hand: delayed presentation of an intact human tooth. A case report.

A 44 year old man presented with a painful, swollen right hand 10 days after a brawl. A radiography showed an intact human tooth embedded in the soft tissue between the metacarpals of the middle and index fingers. The tooth was removed, and the wound debrided and left to heal by second intention. He made a complete recovery. This case emphasizes the importance of a plain radiography, particularly when skin has been breached, and of removal and adequate debridement. Our patient was lucky to have had a successful outcome after so long a delay in treatment.

Supercharged latissimus dorsi muscle flap for coverage of the problem wound in the lower back.

Described is the "supercharging" of a latissimus dorsi muscle flap for coverage of an irradiated nonhealing wound of the lumbar area of the back. Nonhealing wounds of the lower back pose difficult management problems. In the face of radiation therapy, infection, and the presence of foreign materials, they can have the potential for disastrous outcomes. Exposed bone and prosthetic materials in an irradiated bed were covered by turning a latissimus dorsi muscle flap over its lower paraspinous origin and anastomosing the thoracodorsal artery and vein to the ipsilateral superior gluteal vessels. Postoperatively, the patient's wound healed without incident, and the muscle flap and skin graft provided a stable and durable reconstruction. Subsequent duplex Doppler imaging demonstrated a significant inflow to the flap from the superior gluteal artery and vein anastomosed to the thoracodorsal artery and vein of the muscle.

The fate of dermal and dermal-fat grafts.

Histological changes in dermis and dermal-fat grafts have been hampered by the lack of a defined boundary to allow precise localization. We describe a model in which grafts of skin components were coated with india ink and implanted over the perichondrium of pigs' ears. Histological studies were then performed at 2-weekly intervals for 10 weeks. The survival of the grafts was also quantified. Skin adnexal structures found in dermal grafts survived with some changes. Grafts with an epithelial component produced an intense inflammatory infiltrate and formed inclusion cysts. Fat tended to disappear, a significant part of it being replaced by fibrous tissue. Dermis grafts implanted in the ears of growing pigs not only survived, but grew.

Use of costal cartilage cantilever grafts in negroid rhinoplasties.

Dorsal augmentation and nasal tip refinement are important objectives in Negroid rhinoplasty. Use of a costal cartilage cantilever graft will achieve these objectives. We report on our experience in 19 patients. The technique offers an excellent solution to supplying the large amount of material often required to adequately augment the dorsum in these patients. The graft is also versatile enough to allow nasal tip refinement. There are additional aesthetic benefits as the cantilever causes a lengthening in the nasal columella, a reduction in the flare of the nostrils, and increases the columellar-labial angle. The procedure is relatively simple to perform. The problem of warping is minimized by symmetrical carving and the use of large grafts with a substantial cross-section.

Stretching skin: undermining is more important than intraoperative expansion.

The efficacy of intraoperative expansion in reducing the tension of wound closure was tested in young pigs. The young piglet as a model for studying human skin was characterized by finding a close similarity between the modulus of elasticity of young piglet skin and human abdominoplasty and mammaplasty skin (range 12.8 to 23.7 N/mm2 for piglet skin, 14.3 to 19 N/mm2 for human skin). The tension required to close a standardized wound was determined before undermining, after undermining, and finally after intraoperative expansion. These measurements were performed in 10 young pigs with an average weight of 11.5 kg. Undermining the wound edges resulted in a significant decrease in the force required to close the wounds (p less than 0.0001). Intraoperative expansion did not significantly decrease the tension. Previous work showing the importance of site and direction of pull on the tension for wound closure was confirmed in this study. Analysis of variance demonstrated that the tension required to close a standard wound is greater high on the pig's back than near the belly and near the shoulder as opposed to the hip for midflank wounds (p less than 0.0001). Increasing the extent of undermining from 62 to 136 cm2 significantly decreased the tension for wound closure (p less than 0.05). Further undermining did not result in a significant decrease in wound closure tension. In this model, intraoperative expansion offers no advantage over simple undermining. We suggest that the benefit reported by clinicians using intraoperative expansion may derive from an increase in the extent of undermining required to place expanders under the wound margins.