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.

The natural history of the growth of the hand: I. Hand area as a percentage of body surface area.

The use of a patient's own hand as a tool to estimate the area of burn injury is well documented. The area of the palmar surface of one hand has been estimated to be 1 percent of the body surface area. The area of the palmar surface of the hand was measured to test the accuracy of this estimate and then compared with the body surface area as calculated by formulas in common use. This study also sought to determine the natural history of the growth of the hand to permit development of a readily available, bedside means of estimating hand area and body surface area. Bilateral hand tracings were obtained from 800 volunteers ranging in age from 2 to 89 years. The area of each tracing was determined using an integrating planimeter. The height and weight of each individual were measured, and his/her body surface area was calculated. The palmar hand's percentage of body surface area was determined by calculating the quotient for hand area divided by body surface area. Additionally, the width of the hand was measured from the ulnar aspect at the palmar digital crease of the small finger to the point where the thumb rested against the base of the index finger. The length of the hand was measured from the middle of the interstylon to the tip of the middle finger. These two figures were multiplied together to obtain a product which approximated the area of the hand. Based on the most commonly used DuBois formula for calculating body surface area, the area of palmar surface of the hand corresponds to 0.78 +/- 0.08 percent of the body surface area in adults. The percentage varies somewhat with age and reaches a maximum of 0.87 +/- 0.06 percent in young children. Multiplying the length of the hand by its width overestimates the area of the hand as determined by planimetry by only 2 percent. A patient's own hand may be used as a complementary, readily available template for estimation of burn area or other areas of disease or injury. In adults, the area of tracing of the outline of the hand is 0.78 percent of the body surface area, whereas in children, this number tends to be slightly higher. In the emergency room or on the wards, a simple product of length multiplied by width of the hand will closely approximate the area as determined by planimetry. This method allows a more accurate determination of the area of the palmar surface of the hand than the 1 percent estimate, which may lead to an overestimation of the size of a burn wound in adults.

Natural history of the growth of the hand: part II--hand length as a treatment guide in the pediatric trauma patient.

BACKGROUND: In a previous study, we defined the natural history of the growth of the hand. In particular, we demonstrated that the palmar aspect of the hand is approximately 0.78% of body surface area (BSA). We also demonstrated a relationship between the area of the palmar surface of the hand and the total BSA as growth proceeds. Seeking to improve the usefulness of hand size as a guide to predicting body size, we examined the length of the hand as a predictor of body mass and BSA. METHODS: Bilateral hand tracings were obtained from 800 volunteers ranging in age from 2 to 89 years. The hand tracings were measured, and the length and width of the hands were determined. The height and weight of each individual were measured, and his or her BSA was calculated. The data was subjected to statistical and graphical analyses. RESULTS: Hand length is an excellent predictor of BSA and body mass. Hand length as a predictor of body size is independent of the gender of the subject and most accurate for ages 2 to 17 years. The correlation is so highly predictive that it is possible to derive a treatment guide based on hand length. The length of the hand predicts body weight and BSA and can be used to predict baseline intravenous fluid requirements and the volume of packed red blood cells to be transfused to raise the hematocrit 3%. CONCLUSIONS: Hand length is a simple measurement that may be used as a treatment guide. Hand length will predict body weight and body surface area independently of the gender of the subject.

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.

Incidence of operative procedures on cleft lip and palate patients.

The incidence of operative procedures in a group of 374 cleft lip and palate patients was determined by a chart review. These patients were part of a long term study funded by the National Institute of Dental Research at the Lancaster Cleft Palate Clinic. The chart review provided a breakdown of the primary and secondary procedures performed on the patients. Although the secondary procedures carried out were underestimated in this study, it is clear that these operations comprise a major component of the successful treatment of these patients. The results of the study and the implications in today's managed care environment are discussed.

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.

Reversion of uroepithelial cell tumorigenesis by the ectopic expression of human wnt-5a.

Wnt gene family members are thought to play an important role in cell growth and differentiation. When normal wnt gene expression is disrupted, there is the potential for cell transformation. We have found previously that a strong correlation exists between the loss of normal wnt-5a gene expression and cell transformation (Olson and Papkoff, Cell Growth & Differ., 5: 197-206, 1994). Recently, this has been tested directly using antisense wnt-5a, which, when expressed in mouse mammary cells, results in cell transformation (Olson and Gibo, Antisense wnt-5a transforms C57MG mouse mammary epithelial cells, manuscript in preparation). We hypothesize that wnt-5a is a growth-regulating gene, the disruption of which could result in tumorigenesis. The multistage progression of many human cancers involves the loss of normal tumor suppressor gene(s) activity. Several tumor suppressor genes are thought to map to chromosome 3p11-p25. We have studied the ectopic expression of human wnt-5a (3p14-p21) in a tumorigenic uroepithelial cell line with deletion of chromosome 3p13-p21.2. This results in loss of tumorigenicity in athymic nude mice and suppresses anchorage-independent cell growth in soft agar. This suggests that human wnt-5a is a novel tumor suppressor gene in uroepithelial cell carcinoma and may be one of the suppressor genes deleted or rearranged on chromosome 3p.

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.

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.

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.

Elongation of peripheral nerve and viscera containing smooth muscle.

Peripheral nerve, ureter, and small bowel will all elongate over a soft-tissue expander. Elongation of peripheral nerve serves as an effective alternative to nerve grafting both in selected clinical cases and in experimental settings. While canine ureter functions well with little morphologic change following elongation, the rabbit small bowel morphology and function are significantly altered after elongation through expansion.

Technical note: the use of nitroglycerin ointment after precarious neurosurgical wound closure.

It is suggested that the application of nitroglycerin ointment to neurosurgical wound closure exhibiting skin pallor or cyanosis can minimize necrosis and dehiscence. Examples of the use of this agent in patients undergoing myelomeningocele closure as well as in a premature infant undergoing ventriculoperitoneal shunting are described.