Predicting the risk of early atherosclerotic disease development in children after repair of aortic coarctation

AIMS

Increased cardiovascular morbidity is manifested a long time after the repair of aortic coarctation (CoA). By way of impaired flow-mediated vasodilation (FMD) and increased intima media thickness (IMT), surrogate parameters of atherosclerosis, cardiovascular risk factors (RFs) can be correlated with early vascular wall changes in children. This study investigated whether changes in arterial wall function and morphology are detectable in children after coarctation repair.

METHODS AND RESULTS

We examined 28 children after successful repair of CoA vs. 30 control subjects. All children underwent identical screening, with a broad RF profile and FMD/IMT measurements. CoA-children presented significantly (P < 0.001) impaired FMD (4.87 +/- 2.6 vs. 10.2 +/- 3.1%) and higher IMT values (P < 0.001) than the controls (0.48 +/- 0.08 vs. 0.38 +/- 0.05 mm). The blood pressure during rest and exercise and the left ventricular mass were significantly elevated, but no additional RF could be identified in CoA-children. Only a remaining pressure gradient related significantly to FMD.

CONCLUSION

This study documents early vascular wall changes in children after successful coarctation repair. Arterial hypertension and a resting pressure gradient are the major contributing factors to early atherosclerotic development and should be primary targets for therapy. Vascular status should be monitored regularly by FMD and IMT.

CD8(+) T cells express a T-helper 1--like phenotype after burn injury

BACKGROUND

Previous studies suggest that CD8(+) T cells are immunosuppressive after burn injury, but recent reports indicate that CD8(+) T cells have several functions similar to CD4(+) T cells, including the secretion of cytokines. This study uses HY male antigen in transgenic HY female mice to determine the antigen-specific response of activated CD8(+) T cells after burn injury.

METHODS

HY TCR transgenic female mice underwent burn or sham injury. Seventy-two hours after the burn, splenocytes were stimulated with 20 micromol/L HY peptide for 16, 48, and 64 hours; cellular proliferation, intracellular interferon-gamma and interleukin-2, and apoptosis were measured.

RESULTS

Burn injury significantly impaired proliferation to HY antigen (P < or =.05). Activated CD8(+) T cells from burned mice showed increased intracellular interferon-gamma and interleukin-2 16 hours after stimulation compared with sham (P < or =.05) and at no time was less than control mice. The percent of CD8(+) T cells decreased with the time of stimulation but was not due to apoptosis by Annexin V staining.

CONCLUSIONS

Activated CD8(+) T cells express a T(h1)-like phenotype after burn injury. This provides evidence that CD8(+) T cells are not simply suppressive and that is consistent with data that CD4(+) T cells are primed for a T(h1) response after burn injury.

Accuracy of administrative data in trauma: splenic injuries as an example

BACKGROUND

Accurate data are needed to evaluate clinical outcomes, therapeutic modalities, and quality of care in trauma. Administrative data, usually used for billing, have been used to evaluate performance and assess therapy in other medical specialties. This study was performed to determine whether administrative databases are accurate in the recording of information about trauma patients with splenic injuries.

METHODS

Patients who had blunt splenic injuries were identified using a state trauma registry. The medical records of those patients were reviewed. The data collected by chart review were compared with data in the statewide administrative database of patients who had splenic injuries at the same four Level I and II trauma centers in the same 5-year period. Age, sex, admission date, and hospital were matched to assure comparison of the identical cohort. chi2 analysis was used to compare dichotomous data and Student's t test continuous data.

RESULTS

The administrative database identified 641 and the trauma registry identified 529 patients with a diagnosis of splenic injury. A total of 401 patients were found in both databases. Of these, 120 (22.7%) patients were not recorded in the administrative database. Injury Severity Score was underreported by the administrative database (25.74 +/- 14.7 vs. 19.52 +/- 11, p < 0.0001). The administrative database underreported orthopedic, chest, and head injuries (317 vs. 215, 325 vs. 228, and 234 vs. 155, respectively; all p < 0.0001). Use of abdominal computed tomographic scan and diagnostic peritoneal lavage were also underreported (260 vs. 56 and 104 vs.17, both p < 0.0001). The number of operations on the spleen and number of orthopedic procedures were underreported (259 vs. 225, p < 0.014 and 147 vs. 94, p < 0.0001). Complications were markedly underreported by the administrative database (200 vs. 47, p < 0.0001)

CONCLUSION

This study shows that administrative data lack accuracy in the recording of associated injuries, injury severity, diagnostics, procedures, and outcomes data in patients with splenic injuries. Whether these data should be used to evaluate treatment modalities or quality of care in trauma is questionable.

Occupation-related burn injuries

Unlike household burn injuries, the characteristics of burn injuries in the workplace have not been well described. In an effort to understand the causes and effects of occupation-related burn injuries and to aid in prevention, we sought to describe work-related burn injuries by frequency, burn type, age of the patients, body parts burned, and occupation of the patients. This was a statewide, cross-sectional study of all burns that occurred in the workplace during 1994. Data on fatal injuries were obtained from the National Census of Fatal Occupational Injuries. Survey data from the North Carolina Department of Labor were used for nonfatal injuries. Burns caused 34 deaths (15.3%) and 1720 injuries in the workplace in 1994. Of the nonfatal injuries, 1363 (79.2%) were caused by exposure to caustic substances or hot objects or substances. The head and upper extremities were the most frequently injured body parts (936 injuries; 57.6%). The average age of those burned was 30.7 years; most of the patients ranged from 25 to 35 years old. High-risk occupations included vehicle and equipment cleaners, food service personnel, and millwrights (11.3%, 5.3%, and 5.2% of burn injuries, respectively). Unlike the flame burns that occur in homes, exposure to caustics and hot objects and substances caused the majority of on-the-job burn injuries. Protective gear for the head and upper extremities may prevent a significant number of burns. Education and prevention programs may best be directed at workers with high-risk occupations and workers in the 25- to 35-year age range.

Gene expression and cytokine and enzyme activation in the liver after a burn injury

The liver plays a critical role in the inflammatory response to injury; however, the mechanisms by which the liver is affected and how it influences the rest of the immune system are not well understood. Partial hepatectomy is a direct injury to the liver, whereas a burn is an indirect injury to liver, but both injuries appear to produce damage to the liver. In this study, we used a mouse model of 25% total body surface area and 40% total body surface area full-thickness burns to investigate the mechanism of liver damage and response to burn injury by measuring levels of c-Jun messenger (m)RNA, NFkappaB nuclear protein, interleukin-6, transaminases, and liver tissue histology over time. c-Jun and NFkappaB are 2 transcription factors that are induced by partial hepatectomy and related to hepatocyte injury and growth. In both groups of mice with burns, expression of c-Jun mRNA and NFkappaB nuclear protein was activated within 30 minutes after the burn injury, followed by increased levels of interleukin-6 and, finally, elevated enzyme levels. Liver injuries were similar in both groups despite the magnitude of the burns. We believe that these gene products are initiated in the hepatocyte injury after a burn and that they precede other inflammatory responses such as cytokine release, plasma transaminase levels, and histologic changes.

Diagnosis and management of blunt small bowel injury: a survey of the membership of the American Association for the Surgery of Trauma

BACKGROUND

Blunt small bowel injury (SBI) may be difficult to diagnose accurately. Diagnostic delays are associated with increased morbidity and mortality.

METHODS

A cross-sectional survey of members of the American Association for the Surgery of Trauma was conducted. A Likert-type multiple-choice scale was used to evaluate use and usefulness of diagnostic and laboratory tests. Data were analyzed by using univariate and multivariate techniques.

RESULTS

A total of 461 of the 702 members (68%) surveyed responded, of which 133 members (29%) were excluded because they did not currently manage adult SBI. Of the remaining 328 respondents, 244 members (74%) reported prior experience as the most important influence on their current practice of diagnosing blunt SBI. None of the standard laboratory tests were reported as useful. Seventy-seven percent of respondents use computed tomographic (CT) scan most or all of the time for diagnosis (p < 0.05 compared with other modalities). Most respondents estimated their annual incidence of SBI at 5% with a >15% frequency of delay in diagnosis. Forty-four percent of the respondents estimated the mortality associated with a delay in diagnosis at < or =5%. Respondents varied significantly in their management of the patient with an unreliable abdominal exam and a CT scan finding of isolated free fluid. In patients with head injuries, 28% observe, 12% repeat the CT scan, 42% perform diagnostic peritoneal lavage, and 16% operate. For intoxicated patients, 51% observe, 11% repeat the CT scan, 26% perform diagnostic peritoneal lavage, and 10% operate. A more aggressive approach with diagnostic and operative intervention was significantly (p < 0.05) advocated by respondents practicing without residents, more than 15 years out from residency, or by those with a perception of higher morbidity and mortality from delays in diagnosis.

CONCLUSION

There is significant variation in the diagnostic approach to the patient with suspected SBI. The perceived mortality of delayed diagnosis is much less than reported. Those surgeons with more experience or perception of greater morbidity and mortality from a delayed diagnosis are more aggressive. Further investigation into the diagnosis and treatment of this injury is needed.

Transforming growth factor-beta1 and splenocyte apoptotic cell death after burn injuries

Transforming growth factor (TGF)-beta1 is a multifunctional cytokine that mediates apoptotic cell death in human lymphocytes in vitro. To better understand the mechanism through which TGF-beta1 exerts its apoptotic effect, we investigated the role of TGF-beta1 in the relationship between burn injury and cell death of splenocytes in a mouse model of either 0%, 25%, or 40% full-thickness burns. Mice were killed and spleens were harvested at 15 and 30 minutes and at 1, 2, 4, 8, 12, and 24 hours after the burn. The spleens were divided and used for both histologic analyses with H-E stain and TUNEL stain and for total messenger RNA isolation and reverse transcriptase-polymerase chain reaction amplification. Amplified polymerase chain reaction products were analyzed for signal strength by electrophoresis. TGF-beta1 RNA expression was highest at 2 hours after the burn injuries in the 40% full-thickness burns and at 4 hours after the burn injuries in the 25% full-thickness burns. The relative increase in TGF-beta1 RNA was 3 times greater with the larger burn than with the smaller burn. In histologic analysis, splenocyte apoptotic cell death was observed at 4 to 24 hours after the burn in the 40% full-thickness burns but at only 4 to 12 hours in the 25% full-thickness burns. TGF-beta1 RNA peak expression was observed at different times after the burn in 25% and 40% full-thickness burns. Histologic analysis showed apoptotic cell death in proportion with respective messenger RNA expressions. This suggests that TGF-beta1 may be associated with apoptosis of splenocytes in vivo and that the effect of TGF-beta1 after a burn injury may be important in the immune system.

Impact of burn injury on hepatic TGF-beta1 expression and plasma TGF-beta1 levels

BACKGROUND

The liver plays a critical regulatory role in the acute inflammatory response to injury, although the mechanisms of this regulation are not well understood. transforming growth factor-beta1 (TGF-beta1) is induced after burn injury and may contribute to an inhibitory or fatal effect on hepatocytes. We investigated the association over time between plasma concentration of TGF-beta1, expression of TGF-beta1 m-RNA in liver tissue, and histologic analysis of liver apoptosis after burn injury.

METHODS

Male BALB/c mice were anesthetized and randomized to receive 0% (sham), moderate (approximately 25%) (M), or large (approximately 50%) (L) body surface area full-thickness contact burn, followed by resuscitation and analgesia. Animals were killed over a time course from 15 minutes to 24 hours after burn injury, and liver tissue and peripheral blood were collected. Plasma levels of TGF-beta1 (nanograms per milliliter) were measured by enzyme-linked immunosorbent assay. TGF-beta1 m-RNA was extracted from liver and measured by reverse transcription-polymerase chain reaction. Histology of liver apoptosis was examined after fixation and staining with TdT-mediated dUTP nick-end labeling (TUNEL) method.

RESULTS

The plasma concentration of TGF-beta in burn group L was significantly increased at 4 hours after burn when compared with sham and M burn groups. This rise in plasma TGF-beta1 was preceded by an increase in hepatic TGF-beta1 m-RNA expression at 30 minutes, 1, 2, and 4 hours after burn in the L group. Histologic analysis found greater hepatocyte death in the L group than in the M group at 8 hours after burn.

CONCLUSION

The levels of induced TGF-beta1 and TGF-beta1 m-RNA after L burn injury are higher and peak earlier than after M burn injury. Elevated TGF-beta1 may be associated with cell death in hepatocytes. The TGF-beta1 rise may be associated with hepatocyte injury and systemic response to massive burn.

Accuracy of administrative data in trauma

BACKGROUND

Accurate data are needed to evaluate outcomes, therapeutics, and quality of care. This study assesses the accuracy of administrative databases in recording information about trauma patients.

METHODS

Patients with thoracic aorta injury were identified with a state trauma registry, and the medical records were reviewed. Data collected were compared to administrative data on patients with thoracic aorta injuries, at the same hospitals in the same time period.

RESULTS

Fifteen patients (16.3%) with thoracic aorta injury were not recorded in the administrative database, and 23 patients (18.7%) were misdiagnosed. Ninety-one patients were found in both data sources. The administrative database significantly (P < .05) underrecorded abdominal injuries (50 vs 35), orthopedic injuries (117 vs 75), and chest injuries (77 vs 48). The number of aortograms (78 vs 8), type of operative procedures (use of graft; 70 vs 30), use of bypass (35 vs 16), and complications (77 vs 33) were underreported (P < .05). The Injury Severity Score was underestimated by the administrative database (38.65 +/- 12.41 vs 25.66 +/- 9.53; P < .05).

CONCLUSIONS

Administrative data lack accuracy in the recording of associated injury, injury severity, diagnostic, and procedural data. Whether these data should be used to evaluate treatment or quality of care in trauma is questionable.

Percutaneous drainage of pancreatic pseudocysts is associated with a higher failure rate than surgical treatment in unselected patients

OBJECTIVE

The primary aim was to compare directly the effectiveness of percutaneous drainage versus surgical treatment of pancreatic pseudocysts in unselected patients. The authors also wished to identify factors that may predict a successful outcome with percutaneous drainage.

SUMMARY BACKGROUND DATA

Pancreatic pseudocysts are a common complication of pancreatitis, and recent data suggest that many pseudocysts may be observed or treated successfully by percutaneous drainage. Failures with percutaneous drainage have been recognized increasingly, and a direct comparison of percutaneous and surgical treatment was initiated to identify factors that may affect outcome with these approaches.

METHODS

A computerized index search of the medical records of patients with a diagnosis of pancreatic pseudocyst was performed from 1984 to 1995. One hundred seventy-three patients were identified retrospectively and assigned to treatment groups: observation (n = 41), percutaneous drainage (n = 66), or surgical treatment (n = 66). Data on demographics, clinical presentation, pseudocyst etiology and characteristics, diagnostic evaluation, management, and outcome were obtained. Treatment failure was defined as persistence of a symptomatic pseudocyst or the need for additional intervention other than the original treatment.

RESULTS

The etiology of pancreatitis, clinical presentation, and diagnostic evaluation did not differ between groups. Twenty-seven percent had documented chronic pancreatitis, and the etiology of pancreatitis was alcohol in 61% of patients. Mean pseudocyst size was 4.2 +/- 1 cm, 8.2 +/- 1.1 cm, and 7.4 +/- 1.3 cm in the observed, percutaneously treated, and surgically treated groups, respectively. Expectant treatment was successful in 93% of patients. Percutaneous drainage was successful in 42% of patients, whereas surgical treatment resulted in a success rate of 88%. Patients treated by percutaneous drainage had a higher mortality rate (16% vs. 0%), a higher incidence of complications (64% vs. 27%), and a longer hospital stay (45 +/- 5 days vs. 18 +/- 2 days) than patients treated by surgery. Eighty-seven percent of patients in whom percutaneous drainage failed required surgical salvage therapy. Multiple logistic regression analysis failed to reveal any factors significantly associated with a successful outcome after percutaneous drainage.

CONCLUSIONS

Percutaneous drainage results in higher mortality and morbidity rates and a longer hospital stay than surgical treatment of pancreatic pseudocysts. The clinical benefit of percutaneous drainage of pancreatic pseudocysts in unselected patients has not been realized, and the role of this treatment should be established in a clinical trial.

Transforming growth factor-beta impairs postburn immunoglobulin production by limiting B-cell proliferation, but not cellular synthesis

BACKGROUND

Transforming growth factor-beta (TGF-beta) has been shown to be an inhibitor of immunoglobulin (Ig) synthesis and may contribute to decreased Ig synthesis after burn injury. This study investigated the relationship between TGF-beta and Ig synthesis after burn injury.

METHODS

Twenty-four BALB/c mice received either a 30% body surface area full-thickness contact burn or no burn. Splenocytes were isolated 8 days after burn and were cultured with 0, 0.05 or 0.5 ng/mL TGF-beta. After culture, total IgG and total IgM were measured by enzyme-linked immunosorbent assay. The number of IgM-secreting cells per 10(5) cells was measured by enzyme-linked immunoabsorbent spot forming assay. Total IgM per IgM-secreting cell (pg/cell) was calculated.

RESULTS

Total IgG, IgM, IgM-secreting cells, and B-cell number after culture were decreased by burn injury, and the decrease was exacerbated by the presence of TGF-beta. The total IgM per IgM-secreting cells, however, was significantly increased by TGF-beta at 0.5 ng/mL.

CONCLUSION

These data demonstrates that TGF-beta does not specifically impair IgM secretion by committed IgM B cells but appears to decrease B-cell proliferation or clonal expansion.

The effector component of the cytotoxic T-lymphocyte response has a biphasic pattern after burn injury

INTRODUCTION

Burn injury delays allograft rejection and impairs the host defense against infection. These functions are mediated via the cytotoxic T-lymphocyte (CTL) response. The CTL response is divided into antigen recognition/processing and effector phases. Presensitization allows selective analysis of changes, induced by burn injury, in the effector limb of the CTL response in relation to time and burn size.

METHODS

Anesthetized CBA mice were primed with either a flank allograft from C57BL/6 (B6) mice or an autograft (negative control). Five weeks after grafting, animals were anesthetized and received either a 0, 20, or 40% burn. Spleens were harvested 3, 7, 10, and 14 days after burn injury (n = 96), cocultured with B6 stimulator splenocytes, and assessed for CTL response to radiolabeled allogeneic targets in a 51Cr release assay. In experiment 2, spleens were harvested from unburned and 40% burned animals on Postburn Days 3 and 14. After triple staining, cells were analyzed by flow cytometry for CD4, CD8, and CD25 antigens. In experiment 3, splenocytes from 0 and 40% burned animals on Postburn Days 3 and 14, were cocultured with B6 stimulators for 5 days. Supernatants were evaluated for interleukin (IL)-2, IL-5, and interferon-gamma (IFN-gamma) using ELISA:

RESULTS

The CTL response for 20 and 40% burned animals decreased 3 days postburn (-11.9 and -30.1%, P < 0.05), returned to baseline in 7-10 days, and was increased by 14 days postburn (15.8 and 22.6%, P < 0.05). The T-helper lymphocyte population (CD4) from 40% burn animals was significantly decreased on Postburn Days 3 and 14 (10.12 +/- 0.45% vs 11.78 +/- 0.29% and 10.19 +/- 0.24% vs 14.21 +/- 0.97%, respectively, P < 0.05). The CTL effector (CD8) splenocyte population was significantly higher in the burned animals on Postburn Day 14 (4.55% vs 3.71%, P < 0.05). On Postburn Day 3, average IL-5 production was higher in the burned animals (1.80 pg/ml vs 0.59 pg/ml, respectively, P < 0.05). The burn group, on Postburn Days 3 and 14, showed a decrease in mean IL-2 production (212.81 pg/ml vs 263.6 pg/ml and 342.7 pg/ml vs 421.4 pg/ml, respectively, P < 0.05). Mean IFN-gamma production on Postburn Days 3 and 14 was decreased in burned mice (263.75 pg/ml vs 285.57 pg/ml and 218.16 pg/ml vs 263.42 pg/ml, P < 0.05).

CONCLUSIONS

Burn injury impairs the effector limb of the CTL response as a function of burn size in the immediate postburn period. CTL activity returns to baseline within 7-10 days postburn and has a rebound increase by Day 14. Early CTL suppression, after burn injury, may be due to a decrease in the T-helper subpopulation. The late increase in cytotoxicity may be secondary to an increase in the effector CTL population in the late postburn period. Burn injury causes a T-helper-2 phenotype as demonstrated by depressed IL-2 and IFN-gamma production and increased IL-5 production.

Immunogenicity of cultured keratinocyte allografts deficient in major histocompatibility complex antigens

BACKGROUND

Full-thickness (FT) and cultured keratinocyte (CK) allografts have been used as temporary skin replacements in patients with massive burns, but these grafts are ultimately rejected after restoration of host immunocompetence. Genetic engineering has permitted the creation of knockout (KO) mice deficient in class I or class II major histocompatibility antigens. This study examines the immunogenicity of such grafts to determine if these genetically modified keratinocytes could be used for permanent wound coverage.

METHODS

Host sensitization to alloantigen was assessed by second-set rejection. CBA mice (n = 111) were primed with flank grafts consisting of FT and CK allografts from normal C57BL/6 donors, FT and CK class I KO allografts, FT and CK class II KO allografts, and CK autografts. Three weeks later, hosts were challenged with normal tail allografts and observed for second-set rejection. Median graft survival was analyzed by chi2 and Wilcoxon rank tests. In the second experiment, cytotoxic T lymphocytes (CTLs) were harvested from CBA mice (n = 28) 3 weeks after flank grafting. CTL effectors were tested on radiolabeled targets at various ratios in a 51Cr release assay. Dilution curves of CTL activity were compared by analysis of variance.

RESULTS

Hosts primed with CK or FT allografts demonstrated accelerated rejection of second-set tail grafts compared with hosts covered with CBA autografts. CK knockout grafts were less immunogenic than FT knockout skin; class II KO allografts were considerably less immunogenic than class I KO allografts. CTL activity against the knockout CK allografts was negligible compared with that of hosts primed with normal allografts or FT knockout allografts.

CONCLUSION

Although full-thickness knockout skin retains substantial immunogenicity, cultured keratinocytes deficient in class II antigens fail to prime for accelerated second-set rejection and do not elicit a CTL response in the graft recipient. This lack of immunogenicity may permit the indefinite survival of allogeneic knockout keratinocytes in patients requiring massive wound excision and coverage.

Return to jeopardy: the fate of pediatric burn patients who are victims of abuse and neglect

Child abuse and neglect continue to account for a significant number of pediatric burn injuries. Although the epidemiology of intentional burn injuries has been studied, this report compares victims of abuse with victims of neglect. Furthermore, we investigate the long-term fate of both victim and perpetrator. A retrospective search of the North Carolina Jaycee Burn Center database identified 21 abuse and 21 neglect patients among 238 pediatric admissions (mean age, 5.4 years, mean surface area 14%) from 1992 to 1994. The medical, social, and legal records of each patients were examined by two independent reviewers. History, hospital course, and disposition were compared between groups by chi-square analysis and Student's t test. Compared with victims of neglect, abused children were slightly younger (2.1 vs 2.7 years), had somewhat larger burns (12.3% vs 9.05 total body surface area), had inconsistent mechanisms of injury (90% vs 33%, p < 0.002) that were bathroom related (81% vs 29%, p < 0.001), were likely to have a history of abuse (57% vs 24%, p < 0.05) or stigmata of abuse on exam (43% vs 14%, p < 0.05), had longer lengths of stay (23.8 vs 14.1 days, p < 0.05), had similar complication rates, and were place more often in foster care (65% vs 15%, p < 0.01). Inpatient mortality was 5%. Mean follow-up was 108 days, during which time two children were readmitted for repeat abuse. Regarding the caregivers, 57% were single mothers, 36% had been investigated for abuse or neglect, and 12% had lost custody of other children. Of the perpetrators involved in abuse, 71% were charged with a felony, 43% were convicted, and 19% were incarcerated longer than 30 days. Victims of burn abuse and neglect differ considerably in terms of history and disposition but not hospital course. Children in both groups, however, remain at risk for abuse and neglect after discharge. We recommend that more aggressive efforts be made to secure safe environments for these children and that the perpetrator, if clearly identified, be dealt with in a fashion to prevent recurrence of the offense.

Host priming, not target antigen type, decides rejection rate in mice primed with MHC II "knockout" cultured keratinocytes

BACKGROUND

Lack of skin for autograft continues to be problematic in patients with large burns. Allograft and xenograft have been used, but are prone to rapid rejection. Use of cultured keratinocytes (CK) and major histocompatibility complex (MHC) II "knockout" grafts leads to prolonged graft survival compared to allograft. Whether this prolongation is secondary to decreased priming efficacy or target recognition is unknown. Whether a combination of these techniques would generate a less immunogenic allograft remains to be determined.

METHODS

CBA mice (n = 100) were flank-grafted with full thickness C57BL/6 (B6 FT), B6 cultured keratinocytes (B6 CK), B6 major histocompatibility complex II "knockout" full thickness (KO II FT), B6 major histocompatibility complex II "knockout" cultured keratinocytes (KO II CK), or a full thickness autograft (Auto). Three weeks after priming flank grafting, B6, MHC I (KO I), and KO II full thickness tail grafts were placed on each mouse. Tail graft rejection was assessed daily by an observer blinded to flank and tail-graft type. A 4-point grading system for graft color, hair loss, and texture was used.

RESULTS

Animals primed with KO II CK flank grafts had increased survival of tail grafts over B6 FT flank grafted controls (12.3 +/- 1.05 vs 10.1 +/- 1.00, P < 0.05). Within flank graft groups, however, B6, KO I, and KO II tail graft survival was similar.

CONCLUSIONS

KO II CK allografts decrease host priming compared to normal B6 FT allograft. MHC deletion (KO I or KO II) does not protect a target graft from rejection in a primed host. CK and KO techniques may offer a less immunogenic allograft and a readily available source of wound coverage in patients with extensive burns.

Early but not late burn wound excision partially restores viral-specific T lymphocyte cytotoxicity

OBJECTIVE

Early burn wound excision restores immunocompetence and improves patient survival, but the exact mechanisms have not yet been defined. Burn injury impairs cytotoxic T lymphocyte (CTL) activity as a function of burn size, increasing the risk of infection. The purpose of this study was to determine if early wound excision improved viral-specific CTL function.

METHODS

Anesthetized C57BL/6 mice (n = 20) received 0%, 20%, or 40% total body surface area full-thickness contact burns and were inoculated 3 days later with intraperitoneal lymphocytic choriomeningitis virus. Eight days after infection, or 11 days after burn, CTL effectors (E) were harvested and tested against infected, radiolabeled L-Dh targets (T) in a 51Cr-release assay, at varied E:T ratios. Dilution curves of CTL activity were compared by analysis of variance. In the second experiment, mice (n = 18) underwent a 30% burn that was totally excised and grafted on postburn days (PBDs) 0, 3, and 7. Control groups included sham burn and no excision of a 30% burn. In the third experiment, mice (n = 22) received a 30% burn that was partially, completely, or not excised on PBD 3. Control groups included sham burn with and without excision. All groups were infected with intraperitoneal lymphocytic choriomeningitis virus on PBD 3. Viral-specific CTL activity was determined on PBD 11.

RESULTS

Both 20% and 40% burn injury impaired viral-specific CTL function. Wound excision on PBDs 0 and 3, but not on PBD 7, partially restored CTL function. Total excision of the 30% burn improved CTL activity to a greater extent than did partial excision.

CONCLUSION

Burn injury inhibits viral-specific CTL activity. Early, complete wound excision augments CTL function. Improved CTL activity after burn may reduce the risk of infection, providing an immunologic rationale for expeditious wound excision.

Pentoxifylline alters class-specific immunoglobulin synthesis in resuscitated burn injury

Pentoxifylline (PTXF) is a hemorheologic agent that can attenuate microvascular alterations induced by injury, resulting in improved microcirculatory flow. Burn injury-induced immunologic suppression may be caused by alterations in microvascular flow. We studied the effects of PTXF on humoral immunity in resuscitated burn injury. Male AKR mice (n = 80) were randomized to four groups: SHAM, BURN, PTXF-BURN, and NS-BURN (saline burn). Animals were resuscitated with Ringer's lactate and morphine sulfate and put to death at days 1 and 4 after injury. PTXF-BURN animals received PTXF (50 mg/kg intraperitoneally) at the time of resuscitation. Splenic lymphocytes (1 x 10(6) cells/well) were cultured with lipopolysaccharide (LPS) (2.5 and 10 micrograms/ml)). LPS-stimulated in vitro class-specific immunoglobulin (Ig) production was determined by enzyme-linked immunosorbent assay from splenic cell culture supernatants. Burn injury induced a reduction in immunoglobulin (Ig) M synthesis on postburn day 4. PTXF treatment was associated with an increase in IgG production, but a greater depression in IgM synthesis than burn injury alone. PTXF administration during resuscitation in burn injury does not ameliorate the burn-induced depression in IgM synthesis and results in significant potential adverse modulation of humoral immune function.

Evaluation of persistent cough in children

Persistent or chronic cough is defined as a cough lasting more than 3 weeks. A systematic approach to the diagnosis and treatment of chronic cough involves a detailed history. The age of the child, descriptive qualities of the cough, and environmental exposures are particularly important. A thorough physical examination, looking for evidence of growth retardation and failure to thrive in addition to more specific signs, is essential. When further investigation is necessary, a complete blood count, chest radiograph, and PPD are indicated. Additional testing is guided by findings in the history and physical examination to rule out the less common but more serious causes.

Management and outcome of splenic injury: the results of a five-year statewide population-based study

Although splenectomy was the preferred method of treating the injured spleen in the past, the methods of splenorrhaphy and nonoperative management have appeared to gain in popularity. The purpose of this study was to determine whether the management of splenic injuries has changed over the course of time and if there has been any differences in the morbidity and mortality associated with different methods of treatment. We retrospectively examined the discharge records from 2627 patients with splenic injuries from the North Carolina Discharge Database. There were 2258 adults and 369 pediatric patients for evaluation. The rate of nonoperative therapy increased from 33.9 per cent to 46.3 per cent over the 5 years of the study, whereas the rate of splenectomy decreased from 52.9 per cent to 43.4 per cent over the same time period. Splenorrhaphy was used in approximately 10 per cent of the injuries over the course of the entire study period. Adults treated nonoperatively required late operation 6.0 per cent (49/811) of the time. The pediatric late operation rate for nonoperative management was 0.4 per cent(1/231). Reoperation after splenorrhaphy was 2.9 per cent (7/240) for adult patients and 4.3 per cent (2/47) for pediatric patients. The majority of adults (57.2%) with an Injury Severity Score (ISS) < or = 15 were able to be cared for via nonoperative methods, whereas the majority of adults (66.4%) with an ISS > 15 required splenectomy. The majority of pediatric patients were able to be cared for in a nonoperative fashion in both the ISS < or = 15 (83.4%) and ISS > 15 (45.5%).

Effect of cyclo-oxygenase inhibition on in vitro B-cell function after burn injury

The role of PGE2 in suppression of B-cell function after burn injury was investigated. Splenocytes from burned or sham-burned mice were isolated 8 days after burn injury and cultured with lipopolysaccharide with or without the addition of prostaglandin E2 (PGE2) or indomethacin (Indo). Anti-peptidoglycan polysaccharide immunoglobulin (Ig)M (specific antibody to a bacterial antigen), total IgM, and total IgG levels in culture supernatant and lymphocyte proliferation were measured. All B-cell functions were significantly suppressed by burn injury. PGE2 suppressed all B-cell functions except for IgG synthesis. Indo restored anti-peptidoglycan polysaccharide IgM to normal levels, but did not have a significant effect on suppressed proliferation and total IgM synthesis. IgG synthesis was increased by PGE2 and inhibited by Indo. Although not all B-cell suppression was accounted for by PGE2, this prostaglandin appeared to be a mechanism responsible for impaired antigen specific antibody response and isotype switching. Successful restoration of specific antibody synthesis to bacterial antigen suggests a potential therapeutic role for a cyclo-oxygenase blocking agent after burn injury.

Patient, hospital, and surgeon factors associated with breast conservation surgery. A statewide analysis in North Carolina

OBJECTIVE

The objective of this study was to determine the trend of breast conservation surgery (BCS) in North Carolina over a 6-year period and to identify patient, hospital, and surgeon factors associated with the use of BCS.

SUMMARY BACKGROUND DATA

Despite evidence that BCS is an appropriate method of treatment for early stage breast cancer, surgeons in the United States have been slow to adopt this treatment method.

METHODS

Cases of primary breast cancer surgery in all 157 hospitals in the state from 1988 to 1993, inclusive (N = 20,760), were obtained from the State Medical Database Commission, Area Resource File, American Hospital Association and State Board of Medical Examiner's Databases. Multiple logistic regression was used to generate odds ratios (ORs) and 95% confidence intervals (CIs) to determine factors associated with BCS.

RESULTS

The rate of BCS doubled from 7.3% in 1988 to 14.3% in 1993, with an overall rate of 10.2% (2117/ 20.760). Multiple logistic regression identified the following factors associated with BCS: patient age younger than 50 years of age (OR = 1.7, 95% CI = 1.4, 2.1), patient age 50 to 69 years of age (OR = 1.2, 95% CI = 1.1, 1.4), private insurance (OR = 1.2, 95% CI = 1.0, 1.4), hospital bed size 401+(OR = 2.0, 95% CI = 1.6, 2.5), bed size 101 to 400 (OR = 1.7, 95% CI = 1.3, 2.1), and surgeon graduation from medical school since 1981 (OR = 1.6, 95% CI = 1.2, 2.0).

CONCLUSIONS

Rates of BCS in North Carolina are low. Least likely to have BCS were women older than 70 years of age, without private insurance, treated at small hospitals by older surgeons. To increase the use of BCS, widespread education of surgeons, other health care providers, policy makers, and the general public is warranted.

The impact of laparoscopic cholecystectomy on the management and outcome of biliary tract disease in North Carolina: a statewide, population-based, time-series analysis

BACKGROUND

Laparoscopic cholecystectomy (LC) has had a major impact on the treatment of patients with biliary tract disease, but the magnitude and the details of its effects on biliary surgery remain incompletely described. The purpose of this study was to perform a statewide, population-based, time-series analysis of the effects of LC on biliary surgery.

STUDY DESIGN

Patient data were obtained from the statewide hospital discharge database that collects data from all 157 hospitals in the state of North Carolina. All patients with hospital admissions for biliary tract disease from 1988 through 1993 were selected for analysis.

RESULTS

The use of open cholecystectomy (OC) dropped from 100 percent of all cholecystectomies in 1988 to 32.3 percent in 1993, while LC increased from eight cases in 1988 to over 7,800 per year in 1993. The increase in the rate of LC was not associated with an increase in the overall rate of cholecystectomy. Bile duct (BD) repairs increased from 13 in 1988 to a high of 36 in 1992. There was a strong, statistically significant correlation between the rate of LCs and the rate of BD repairs (R = 0.89, p = 0.0001). Hospital charges and component charges were lower for patients having elective LC compared to those having elective OC (p = 0.001). This remained true after stratification by age and type of gallbladder disease. Hospital stays were shorter for patients having LC than for those having OC (p = 0.001 for all). Surgeons in smaller hospitals were slower at adopting LC. Younger and board certified surgeons adopted LC more rapidly than older and non-board certified surgeons.

CONCLUSIONS

In North Carolina, LCs progressed from nonexistent to the dominant approach for managing patients with cholelithiasis in a matter of a few years. Associated with this change were shorter hospitalizations and lower charges. Contrary to other published reports, North Carolina did not experience an increase in the overall rate of cholecystectomy with the adoption of LC. There was a highly correlated increase in the rate of bile duct repairs in the first years of the study.

Allogeneic fibroblasts used to grow cultured epidermal autografts persist in vivo and sensitize the graft recipient for accelerated second-set rejection

INTRODUCTION

Cultured epidermal autografts (CEAs) have been used for wound coverage in patients with massive burns and other skin defects. However, CEAs often display late breakdown, which may be immunologically mediated and initiated by persistent foreign fibroblasts used as a feeder layer to optimize keratinocyte growth. This study investigates whether these fibroblasts, previously shown to persist in vitro, survive after grafting and induce host sensitization to alloantigen.

METHODS

CEAs from CBA donors (H-2k) were grown on allogeneic NIH 3T3 (H-2q) or syngeneic LTK (H-2k) fibroblasts, which were removed by trypsinization 7 days later. CBA mice (n = 85) were flank-grafted with NIH allografts (positive control), CEA/3T3s, CEA/LTKs, or CBA autografts (negative control). Hosts were challenged with second set NIH tail allografts 3 weeks later. Median graft survival was compared between groups by Wilcoxon rank and chi 2 analysis. Additional CBA mice (n = 15) received CEAs that were biopsied 0, 4, and 8 days after grafting. The presence of allogeneic fibroblasts was determined by Western immunoblotting, using KL295, a monoclonal antibody that recognizes H-2q (but not H-2k) class II histocompatibility antigens.

RESULTS

Allogeneic fibroblasts persisted after grafting but decreased over time, as determined by alloantigen expression on Western immunoblots. Accelerated tail graft rejection occurred in hosts primed by NIH allografts (9 days, p < 0.05), as well as by CEAs growth with an allogeneic (10 days, p < 0.05) but not a syngeneic feeder layer (12 days, NS). Mice receiving flank autografts rejected second set tail allografts at 12 days.

CONCLUSIONS

Immunogenic fibroblasts used to grow CEAs survive in vivo and sensitize the graft recipient for accelerated second-set rejection. These persistent cells may initiate an inflammatory response that may result in late graft breakdown and limit the utility of CEAs grown with a foreign fibroblast feeder layer.

Immediate burn wound excision restores antibody synthesis to bacterial antigen

Although burn wound excision and grafting have been shown to improve patient survival, the effects on immune function, especially humoral immunity, are not completely understood. The purpose of this study was to investigate the effect of immediate and early wound excision on antibody synthesis and B-cell proliferation, specifically, antibody response to PGPS, a ubiquitous bacterial cell wall antigen. Thirty-six male BALB/c mice were divided into four groups. Sham mice received no burn, and remaining mice received a 30% body surface area full-thickness burn. Under general anesthesia, excision and grafting was performed either 6 or 72 hr after injury (BE&G6 and BE&G72 groups). A fourth control group received burn but did not undergo excision and grafting (Burn group). Splenocytes were isolated 8 days postburn and stimulated with 2.5 microgram/ml lipopolysaccharide. Anti-PGPS IgM, total IgM, and total IgG levels were determined by ELISA. B-cell proliferation, measured by [3H]-thymidine uptake, was expressed as stimulation index. All B-cell functions were significantly suppressed by burn injury. Immediate excision and grafting (BE&G6) restored anti-PGPS IgM synthesis to normal, while nonspecific B-cell functions did not change significantly. Early excision and grafting (BE&G72), however, failed to significantly improve any B-cell functions. Immediate but not early BE&G restored antibody synthesis to the bacterial cell wall antigen (PGPS). Immediate BE&G may therefore lead to a decrease in bacterial infection after burn injury.

A statewide, population-based time-series analysis of the outcome of ruptured abdominal aortic aneurysm

OBJECTIVES

The purpose of this study was to perform the first statewide, population-based, time-series analysis of the frequency of ruptured abdominal aortic aneurysm (RAAA), to determine the outcomes of RAAA, and to assess the association of patient, physician, and hospital factors with survival after RAAA. The hypotheses of the study were as follows: 1) the rate of RAAA would increase over time and 2) patient, surgeon, and hospital factors would be associated with survival.

BACKGROUND

Ruptured abdominal aortic aneurysm is a life-threatening emergency that presents the surgeon with a technically demanding challenge that must be met and surmounted in a short time if the patient is to survive.

METHODS

Data were obtained from the following four separate data sources: 1) the North Carolina Hospital Discharge database, 2) the North Carolina American Hospital Association database, 3) the North Carolina State Medical Examiner's database, and 4) the Area Resource File. All patients with the diagnosis of an abdominal aortic aneurysm (AAA) were selected for initial assessment. Patients were grouped into those with and those without rupture of the abdominal aneurysm.

RESULTS

During the 6 years of the study, 14,138 patients were admitted with a diagnosis of AAA. Of these, 1480 (10%) had an RAAA. The yearly number of patients with elective AAAs increased 33% from 1889 in 1988 to 2518 in 1993. The yearly number of RAAAs increased 27% from 203 to 258. The mortality rate for AAA was 5%, as compared with 54% in RAAA patients. The patient's age was found to be the most powerful predictor of survival. Univariate logistic regression analyses demonstrated an association of the surgeon's experience with RAAA and patient survival after RAAA. Analysis of the survival rates of board-certified and nonboard-certified surgeons demonstrated that patients with RAAAs who were treated by board-certified surgeons had significantly better survival. When the survival was compared in small (less than 100 beds) and large (more than 100 beds) hospitals, survival was significantly better in the larger hospitals.

CONCLUSIONS

Ruptured abdominal aortic aneurysm remains a highly lethal lesion, even in the best of hands. Despite the many improvements in the care of seriously ill patients, there was no significant improvement in the survival of RAAA during this study. This suggests that early diagnosis is the best hope of survival in these patients. The study demonstrated that survival after RAAA was related most strongly to patient age at the time of the RAAA. The physician's and the hospital's experience with RAAA, the physician's background as measured by board certification, and the type of hospital at which the operation was performed (small vs. large) also may be associated with survival. These findings may have important implications for the regionalization of care and the education and credentialling of physicians. Given the lack of recent progress of improving the outcome of RAAA, aggressive efforts to treat patients before rupture are appropriate.

Differences in IgM synthesis to gut bacterial peptidoglycan polysaccharide after burn injury and gut ischemia

Both burn injury and intestinal ischemia have been proven to induce bacterial translocation from the gut. It is still unknown, however, whether the bacteria induces immune response in these different models. To assess this, we measured in vitro IgM synthesis to peptidoglycan polysaccharide (PGPS), a ubiquitous gut bacterial antigen, after burn injury or gut ischemia-reperfusion in a mouse model. Eighty-five BALB/c mice were divided into four groups. Gut ischemia was produced by placing a vessel loop around the superior mesenteric artery at celiotomy (group Isc; n = 31). After 45 minutes, the abdomen was reopened, and the vessel loop removed. All animals had visible gut ischemia. Control mice (group Isc-C; n = 15) underwent two sham operations. Burn injury was 25% body surface area full-thickness to the dorsum (group B; n = 27). Another control group (B-C; n = 12) was also used. Animals were euthanized 24 hours after recirculation or 5 days after the burn injury. All spleens were removed, and cell suspensions prepared. Cells were cultured in 2.5 micrograms/ml lipopolysaccharide for 5 days, and anti-PGPS IgM level in the supernatant was measured by an enzyme-linked immunosorbent assay. Intestinal ischemia produced a significant rise in in vitro anti-PGPS IgM synthesis per 10(5) lymphocytes, which is the principal immunoglobulin response to infection. However, anti-PGPS IgM in mice after burn injury was significantly decreased. This decreased IgM synthesis after burn injury compared to gut ischemia may represent continued immune impairment from the burn wound, and may account for organ dysfunction related to bacterial translocation after burn injury.

The impact of femur fracture with associated soft tissue injury on immune function and intestinal permeability

Alterations in intestinal permeability and immune function were investigated in a murine femur fracture (FFx) model. We postulated that soft tissue injury associated with closed FFx (crush injury) would result in greater immunosuppression that open FFx (surgical division). AKR mice were randomized to four groups (Normal, Sham, Open FFx, Closed FFx) and studied at 24 and 96 h post-injury. Immune function was assessed by splenocyte blastogenic response and class-specific immunoglobulin production. Intestinal permeability was assessed by measurement of whole blood fluorometry after gavage administration of fluorescein-dextran (FITC-dextran). Closed FFx is associated with increased splenocyte blastogenesis and increased immunoglobulin production at 24 h post-injury. This immunostimulatory response was associated with altered intestinal permeability early after injury (FITC-dextran:.185 +/- .070 Closed FFx vs. .069 +/- .011 Normal, p = .06). Immunosuppression was evident at 96 h post-injury in the closed FFx group, documented by significant reductions in splenocyte blastogenesis to all mitogens studied. The Open FFx group did not demonstrate any reduction in splenocyte blastogenesis at 96 h post-injury. These data suggest that the soft tissue injury associated with Closed FFx is associated with significant immunosuppression and altered gastrointestinal permeability, which may adversely affect the host by increasing the relative risk of post-trauma infection.

Prevention of blood exposure. Body and facial protection

Regardless of the specific clinical setting in the operating room, it is clear that better protection of all personnel is an appropriate objective in the current environment. Better protection through improved PPE and modification of operational practices is essential. A prompt response to blood contact when it does occur is likewise appropriate. With conscientious applications of methods to reduce blood exposure, it is hoped that the operating room can become a safer place with respect to occupational infections from bloodborne pathogens.

The 1995 Moyer Award. The effect of burn injury on allograft rejection, alloantigen processing, and cytotoxic T-lymphocyte sensitization

Burn injury impairs cellular immunity, increases the risk of viral infection, and delays allograft rejection, but little is known about its effect on antigen processing and cytotoxic T-lymphocyte (CTL) function. This study examined the effect of burn injury on alloantigen sensitization with an in vivo model of second-set rejection and in vitro assays of CTL alloreactivity. Anesthetized CBA mice (n = 95) received a 0%, 20%, or 40% full-thickness contact burn that was partially excised 3 days later and covered with autograft or C57BL/6 allograft. Two weeks after the burn was inflicted, mice were challenged with second-set tail allografts, which were observed for rejection. Median graft survival times were compared by Wilcoxon rank and chi-squared analysis. Additional CBA mice (n = 24) underwent similar burn injury, excision, and grafting. Splenocytes were harvested 2 weeks later and were used as CTL effectors against radiolabeled targets. Dilution curves of target lysis were compared by analysis of variance. Forty percent burn injury prolonged unprimed allograft survival from 13 to 15 days (p < 0.01) but had a greater effect on primed allograft survival, which increased from 9 to 12.5 days (p < 0.01). Furthermore, a 40% burn eliminated the influence of priming, resulting in second-set graft survival similar to that of mice in an unburned, unprimed control group (12.5 vs. 13 days, NS). Whereas 20% burn injury did not inhibit CTL priming, a 40% burn profoundly impaired CTL function (p < 0.001), which recovered only after 6 days of in vitro allostimulation. Burn injury inhibits both alloantigen priming and the immunologic memory of CTLs as a function of burn size. This impairment in alloantigen processing helps to explain defects in cellular immunity and suggests a mechanism for prolonged allograft survival and decreased viral resistance after burn injury occurs.

Burn injury impairs second-set rejection and CTL reactivity in mice primed by cultured keratinocyte allografts

Cultured keratinocyte (CK) allografts have limited antigenicity and have been used as a skin replacement in patients with massive thermal injury. Recent data indicate that CK grafts are more immunogenic than previously believed and could compromise wound healing in the immunocompetent host. The purpose of this study was to determine if the immunosuppression of burn injury might affect the alloantigen response and minimize sensitization to CK allografts. CBA mice received a 0%, 20%, or 40% burn that was partially excised three days later and grafted with a full-thickness (FT) skin allograft, CK allograft, or CK autograft. Two weeks postburn, mice received FT tail skin allografts, which were observed for rejection. We observed that FT and CK allografts primed the unburned host with equal efficacy. However, burn injury selectively minimized priming by CK allografts, resulting in delayed rejection of second-set allografts. With evidence that burn injury inhibits host sensitization to CK allografts, we then examined the effect of burn size on CTL alloreactivity. Additional CBA mice underwent burn injury, excision, and grafting as described above. Host splenocytes were harvested two weeks later and tested on radiolabeled targets for allospecific cytotoxicity. CTLs from unburned mice primed with FT allografts demonstrated the greatest CTL lysis, followed next by CTLs from unburned mice covered with CK allografts. Burn injury inhibited CTL activity as a function of wound size. Activity of CTLs from burned mice primed with CK allografts improved after in vitro allostimulation but remained below that of CTLs from unburned, unprimed mice. We conclude that burn injury selectively inhibits the allospecific response to CK allografts. The decreased immunogenicity of CK allografts, when used for burn wound coverage, may improve the long-term survival of allogeneic keratinocytes, enhancing their potential as a biologic skin replacement.

The relationship between interferon-gamma and keratinocyte alloantigen expression after burn injury

BACKGROUND

Cultured keratinocyte (CK) and cadaveric skin allografts have prolonged survival in patients with massive thermal injury. It is unclear if this delayed rejection is due to impaired host responsiveness or decreased graft immunogenicity. Although burn injury has been shown to decrease parameters of allograft response, no studies have examined the effect of burn injury on alloantigen expression. This study investigated the effect of burn size on class II antigen expression in CK allografts as well as on tissue levels of interferon-gamma (IFN-gamma), the principle regulator of alloantigen expression.

METHODS

Anesthetized CBA mice (n = 64) received a 0%, 20% partial-thickness (PT), 20% full-thickness (FT), or 40% FT contact burn. Forty-eight hours later, wounds were partially excised and covered with CK allografts from C57BL/6 donors. Five days after burn injury, grafts were analyzed for donor-specific class II antigen. Protein expression was determined by Western immunoblotting and quantified with video densitometry. Wound, serum, and unburned skin levels of IFN-gamma were determined by enzyme-linked immunosorbent assay. Groups were compared by Fisher's analysis of variance.

RESULTS

As burn size increased, class II antigen expression decreased (p < 0.001). This corresponded with decreased wound and skin levels of IFN-gamma after 40% burn (p < 0.05); however, wound IFN-gamma was significantly elevated after 20% PT and FT burns (p < 0.01). Serum IFN-gamma increased as burn size increased (p < 0.01).

CONCLUSIONS

Burn injury decreases the antigenicity of CK allografts, which partly explains delayed allograft rejection after burn injury. Although wound IFN-gamma increases after minor thermal injury, the profound decrease in wound and skin IFN-gamma after a major burn corresponds with diminished class II antigen expression. The decreased availability of IFN-gamma after major thermal injury provides a mechanism for limited allograft tolerance.

A statewide, population-based time-series analysis of the increasing frequency of nonoperative management of abdominal solid organ injury

Emergency operative intervention has been one of the cornerstones of the care of the injured patient. Over the past several years, nonoperative management has increasing been recommended for the care of selected blunt abdominal solid organ injuries. The purpose of this study was to utilize a large statewide, population-based data set to perform a time-series analysis of the practice of physicians caring for blunt solid organ injury of the abdomen. The study was designed to assess the changing frequency and the outcomes of operative and nonoperative treatments for blunt hepatic and splenic injuries.

METHODS

Data were obtained from the state hospital discharge data base, which tracks information on all hospitalized patients from each of the 157 hospitals in the state of North Carolina. All trauma patients who had sustained injury to a solid abdominal organ (kidney, liver, or spleen) were selected for initial analysis.

RESULTS

During the 5 years of the study, 210,256 trauma patients were admitted to the state's hospitals (42,051 +/- 7802 per year). The frequency of nonoperative interventions for hepatic and splenic injuries increased over the period studied. The frequency of nonoperative management of hepatic injuries increased from 55% in 1988 to 79% in 1992 in patients with hepatic injuries and from 34% to 46% in patients with splenic injuries. The rate of nonoperative management of hepatic injuries increased from 54% to 64% in nontrauma centers compared with an increase from 56% to 74% in trauma centers (p = 0.01). In patients with splenic injuries, the rate of nonoperative management increased from 35% to 44% in nontrauma centers compared with an increase from 33% to 49% in trauma centers (p < 0.05). The rate of nonoperative management was associated with the organ injury severity, ranging from 90% for minor injuries to 19%-40% for severe injuries. Finally, in an attempt to compare blood use in operatively and nonoperatively treated patients, the total charges for blood were compared in the two groups. When compared, based on organ injury severity, the total blood used, as measured by charges, was lower for nonoperatively treated patients.

CONCLUSIONS

This large, statewide, population-based time-series analysis shows that the management of blunt injury of solid abdominal organs has changed over time. The incidence of nonoperative management for both hepatic and splenic injuries has increased. The study indicates that the rates of nonoperative management vary in relation to the severity of the organ injury. The rates increase in nonoperative management were greater in trauma centers than in nontrauma centers. These findings are consistent with the hypothesis that this newer approach to the care of blunt injury of solid abdominal organs is being led by the state's trauma centers.

Early, complete burn wound excision partially restores cytotoxic T lymphocyte function

BACKGROUND

Cytotoxic lymphocytes (CTLs) are an important component of immune function, involved in antigen recognition and resistance to viral infection. Burn injury suppresses cell-mediated immunity, induces allograft tolerance, and increases the risk of viral infection, but the mechanisms are not well understood. This study analyzes the effect of burn size and burn wound excision on CTL activity.

METHODS

Anesthetized CBA mice (n = 12) received a 0%, 20%, or 40% body surface area contact burn. Additional mice (n = 16) received a 40% burn that was totally, partially, or not excised 72 hours after burn. Excised areas were covered with normal, syngeneic skin. Two weeks later harvested splenocytes were cocultured with allogeneic stimulators. CTL activity was determined by a 51Cr release assay, in which CTL effectors were tested on allogeneic, radiolabeled targets. Dilution curves of CTL activity were compared by ANOVA:

RESULTS

Both 20% and 40% burns significantly inhibited CTL activity (p < 0.05). Total but not partial excision of a 40% burn restored CTL activity (p < 0.01). Both total and partial wound excision also improved survival (p < 0.05).

CONCLUSIONS

Burn injury inhibits CTL activity in a size-dependent manner, and total wound excision significantly improves both CTL function and survival after injury. This study suggests a mechanism for the immunosuppressive effects of burn injury and provides an immunologic rationale for early, complete burn wound excision.

Burn injury induces a biphasic immunoglobulin M response to bacterial antigen

We studied 75 BALB/c mice to examine the role of impaired immunoglobulin M (IgM) synthesis in the increased risk of bacterial infection after burn injury by investigating the kinetics of IgM synthesis to peptidoglycan polysaccharide (PGPS), a ubiquitous bacterial antigen. Splenocytes were isolated 1, 5, and 8 days postburn (PBD) and cultured with lipopolysaccharide for 5 days. Culture supernatant was collected and anti-PGPS IgM and total IgM levels were measured by ELISA. Total IgM-secreting cells were measured by ELISPOT assay. Total IgM and anti-PGPS IgM per IgM-secreting cell were calculated. On PBD 1, anti-PGPS IgM synthesis but not total IgM synthesis is increased in burned animals. By PBD 5, total IgM and anti-PGPS IgM synthesis in the burn group start to fall and by PBD 8, both are significantly decreased. The early increase in anti-PGPS IgM synthesis represents a positive response to bacterial challenge. However, the late nonspecific decrease in total IgM and anti-PGPS IgM synthesis suggests a potential mechanism for increased susceptibility to bacterial infection 5 to 10 days after burn injury.

Xenogeneic mouse fibroblasts persist in human cultured epidermal grafts: a possible mechanism of graft loss

Recent reports suggest that long-term graft take of cultured epidermal autografts (CEAs) is less than 50% when late graft loss is considered. The characteristics of late CEA loss suggest that it may occur as a result of an immunologic reaction to persistent xenogeneic cells and/or proteins used to grow CEA. In this study we examined whether immunologically reactive, mouse 3T3 fibroblasts used as feeder layers can persist in primary, secondary, and tertiary human CEA. We cocultured keratinocytes from 11 separate burn patients with growth-arrested 3T3 fibroblasts. After removing visible 3T3 fibroblasts from CEA with trypsinization, we allowed CEA to reach confluence. We then harvested CEA either as primary, secondary, or tertiary cultures. We detected mouse fibroblasts using fluorescence activated cell sorting (FACS) with a monoclonal antibody specific for mouse major histocompatibility (MHC) antigens. We detected mouse MHC class II antigens by performing Western immunoblotting with another mouse MHC-specific monoclonal antibody. By FACS we identified mouse fibroblasts in 100, 75, and 62.5% of primary, secondary, and tertiary passage CEAs, respectively. Similarly by immunoblotting we found mouse MHC class II antigen in 100, 80, and 66.7% of primary, secondary, and tertiary CEAs. These results demonstrate that xenogeneic fibroblast feeder layers capable of generating immunogenic transplantation antigens persist in CEAs. The persistence of these cells and their antigen expression may contribute to CEA loss.

Immunoglobulin M synthesis after burn injury: the effects of chronic ethanol on postinjury synthesis

The effect of chronic ethanol ingestion on class-specific immunoglobulin (Ig) synthesis after burn injury was investigated in C57BL/6 mice. Animals were divided into four groups: control, burn, ethanol-sham, and ethanol-burn groups. Five days after injury or the last ethanol ingestion, cell suspensions from spleen and mesenteric lymph nodes were prepared. The number of class-specific Ig-bearing cells were counted by flow cytometry. The cell suspensions were cultured with lipopolysaccharide for 4 days. The supernatants from these cultures were tested for class-specific Ig by enzyme-linked immunoassay. No change occurred in the amount of class-specific IgG and IgA produced by 10(5) lymphocytes calculated from both of these data. Both burn and ethanol alone impaired IgM synthesis; splenic IgM was most affected by burn, and mesenteric lymph node IgM was most affected by ethanol. The group receiving ethanol before burn had IgM synthesis significantly impaired in both lymphocyte populations. Because IgM is the most important Ig in resistance to bacterial infection, this consistent suppression of IgM synthesis in both these tissues may contribute to increased incidence and severity of acute infection.

Ethanol ingestion potentiates PMN migration into small intestine after ischemia

Neutrophils have been identified to play a major role in ischemia/reperfusion injury through several mechanisms. Neutrophil migration into reperfused gut may reduce bacterial translocation, but may also enhance the reperfusion injury. Ethanol ingestion impairs cutaneous chemotaxis, but its effects on neutrophil migration to postischemic small bowel are unknown. This study investigates the effects of ethanol on small bowel accumulation of neutrophils after ischemia/reperfusion. Ninety-five rats were divided into five groups; normal control, sham operation, ethanol-sham, ischemia, and ethanol-ischemia groups. Ethanol was given once acutely by gavage (3 g/kg, 20% solution) to the animals in the ethanol-sham and the ethanol-ischemia groups 4 hr before ischemic injury. Ischemia was produced for 1 hr by placing a vessel loop around the superior mesenteric vessels. After 1 hr, 87% of animals had gut ischemia and the loop was removed. Three hours later the small bowel was examined for necrosis and the reperfused viable small bowel was extirpated for measurement of neutrophil infiltration by colorimetric assay for myeloperoxidase (MPO), an enzyme restricted to neutrophils. Both ethanol and ischemia/reperfusion produced significant independent increase in the MPO activity. When ethanol was given prior to ischemia, the MPO activity was further increased by statistically significant margin. The present study demonstrated that ethanol enhanced the effects of gut ischemia/reperfusion injury on PMN accumulation into the intestinal wall. These observations suggest that ethanol may potentiate ischemic injury to the gut and lead to increased problems when gut blood flow is significantly impaired.

Prospective analysis of outcome after cardiopulmonary resuscitation in critically ill surgical patients

BACKGROUND

This study was done to examine the outcome of cardiopulmonary resuscitation (CPR) in the surgical intensive care unit (SICU) and to identify factors preceding cardiopulmonary arrest that could predict survival.

STUDY DESIGN

We prospectively collected demographic, laboratory, diagnostic, and complications data in our SICU database on 5,237 consecutive patients and reviewed the charts of all patients receiving CPR.

RESULTS

Cardiopulmonary resuscitation was performed upon 1.1 percent (55 of 5,237 patients) of patients in the SICU. Twenty-nine percent (16 of 55 patients) survived greater than 24 hours but died in the hospital, and 13 percent (seven of 55 patients) survived to discharge. No patient with a worsening Glasgow Coma Scale (GCS) score, acute physiology score (APS), or any acute organ failure who had cardiopulmonary arrest survived. Survival after CPR for patients with a stable or improving APS was 32 percent (p < 0.01).

CONCLUSIONS

Patients in the SICU who survived CPR had a stable or improving clinical course as determined by APS and GCS score, and had not had acute organ failure. Patients who were critically ill with a declining clinical course did not survive after CPR.

Management and outcome of abdominal shotgun wounds. Trauma score and the role of exploratory laparotomy

OBJECTIVE

The management and outcome of 138 abdominal shotgun wounds were examined over a 5-year period.

SUMMARY BACKGROUND DATA

It has been proposed that exploratory laparotomy may be unnecessary and even overused in a subset of patients with abdominal shotgun wounds.

METHODS

Data on shotgun wound patients from October 1987 through March 1992 from a statewide trauma registry were examined. Patients with abdominal shotgun wounds were identified and compared with patients with nonabdominal shotgun wounds.

RESULTS

Of 516 shotgun wound patients, 138 (26.7%) had abdominal wounds and 88 (63.8%) had exploratory laparotomies. Abdominal shotgun wounds resulted in significantly longer number of intensive care unit days (4.3 vs. 2.5, p < 0.05), a greater number of blood units transfused (7.8 vs. 2.4, p < 0.05), and a higher mortality (15.9% vs. 4.8%, p < 0.05) when compared with nonabdominal shotgun wounds. When stratified for trauma score, the mortality for abdominal shotgun wounds always was significantly greater than for nonabdominal shotgun wounds. All abdominal shotgun wound patients with trauma scores less than ten died. The negative laparotomy rate for abdominal shotgun wound patients with normal trauma scores was 9.4%. No patient with a negative laparotomy died.

CONCLUSION

Abdominal shotgun wounds are a particularly lethal subset of shotgun wounds. Although some abdominal shotgun wound patients can be managed without laparotomy, the morbidity and mortality for these injuries are substantial, even in patients with normal trauma score. Clinical judgment is an excellent predictor of the need for laparotomy.

Chronic ethanol intake and burn injury: evidence for synergistic alteration in gut and immune integrity

OBJECTIVE

Chronic ethanol (EtOH) intake and injury are both associated with increased susceptibility to infection in the host. This study examined the immune and gastrointestinal alterations induced by chronic EtOH intake and injury, and compared the effects of enteral and intravenous administration of EtOH.

DESIGN

Rats received 20% EtOH daily for 14 days by gavage [oral (PO)] or superior vena cava [intravenous (i.v.)] infusion. Mean blood EtOH concentrations at 90 minutes after administration were 95.3 mg/dL (PO) and 94.4 mg/dL (i.v.). An additional group of animals underwent a 30% total body surface area full-thickness burn injury 4 hours after the final dose of EtOH or normal saline on experimental day 14. All animals were killed 4 days after burn injury.

MATERIALS AND METHODS

Nonadherent splenic lymphocytes were tested for mitogenic responses to the T-cell mitogens concanavalin A (ConA) and phytohemagglutinin (PHA), and the B-cell mitogens lipopolysaccharide (LPS) and pokeweed. Quantitative bacterial cultures of mesenteric lymph nodes and liver were also performed. Alterations of intestinal mucosa were determined by measurement of ileal mucosal weight, DNA, protein, and diamine oxidase content. Circulating plasma endotoxin concentrations were also measured.

MEASUREMENTS AND MAIN RESULTS

Chronic PO-EtOH intake induced a significant impairment in mitogenic response to T-cell mitogens, with a fourfold reduction in ConA and a twofold reduction in PHA response (p < 0.05 by analysis of variance) and increased bacterial translocation (70% vs. 10%). Chronic EtOH administered by the i.v. route did not reduce mitogenic response to any of the mitogens studied. Histologic examination of ileal segments demonstrated that chronic PO-EtOH administration was associated with significant mucosal disruption and exfoliation. Chronic administration of PO-EtOH prior to burn injury induced a significant impairment in spleen mitogenic response to ConA, PHA, and LPS when compared with all other burn injury groups. Chronic administration of EtOH by the i.v. route prior to burn injury did not alter splenic mitogenesis. In addition, chronic PO-EtOH prior to burn injury increased bacterial translocation rates (80% vs. 33%) and prevented the normal intestinal reparative response to burn injury (demonstrated by a significant reduction in ileal mucosal weight, DNA, and diamine oxidase content).

CONCLUSIONS

Enteral but not i.v. administration of EtOH induced significant immunologic dysfunction (demonstrated by altered spleen mitogenic response) and gastrointestinal dysfunction (demonstrated by depressed ileal mucosal weight, DNA, and diamine oxidase content, and increased bacterial translocation rates). In addition, the administration of chronic enteral EtOH prior to injury resulted in significant immune suppression and impaired the host's ability for normal intestinal repair. These results suggest that this EtOH-induced reduction in immunocompetence may be gut-mediated and that the administration of alcohol prior to injury may result in a synergistic alteration of gut and immune integrity.

Regional and institutional variation in burn care

In reviewing the literature on burn therapy and observing clinical burn care, we noted differences among institutions and individual experts in several areas. To study variation in burn care, we surveyed the 140 burn centers listed by the American Burn Association to determine how burn care is currently administered in the United States and Canada. Responses were obtained from 83 hospitals (60%). The survey addressed resuscitation, operative and nonoperative wound care, medications, antimicrobial agents, and pain control. The major influence on care appeared to be the experience of the director (considered "very influential" in 85%) compared with the literature ("very influential" in 12%) and habit/what works for us ("very influential" in 48%). The Parkland formula was used "always" or "often" by 78%, and the Brooke formula "never" by 81% of respondents. Lactated Ringer's solution was the most popular initial fluid, and most (78%) respondents changed fluids after 24 hours. However, the fluids used in the second 24 hours varied equally among several choices. The use of colloids also varied without a set pattern. Furosemide (Lasix) and nonsteroidal antiinflammatory drugs were used "rarely" or "never" by 67% of centers in the acute stage. H2 blockers were used for gastritis prophylaxis "always" or "often" in 60% (vs 53% for antacids and 20% for sucralfate [Carafate]). Tube feedings were started on day 1 after burn injury "always" by less than 30% of centers. Total parenteral nutrition was not commonly used. Most centers use of silver sulfadiazine on the body and hands, but facial topical antimicrobial therapy varied.(ABSTRACT TRUNCATED AT 250 WORDS)

Dehydroepiandrosterone fails to improve immunoglobulin synthesis and lymphocyte mitogenic response after burn injury

Dehydroepiandrosterone has been proposed as a means of restoring immune function after injury. In this study we examined the effect of dehydroepiandrosterone on the impaired immunoglobulin M synthesis and depressed lymphocyte mitogenic responses observed after burn injury. We divided BALB/c mice (n = 28) into four equal groups that received either a 25% total body surface area dorsal steam burn or a sham procedure. One hour later we injected mice subcutaneously either with 100 micrograms dehydroepiandrosterone or vehicle alone. Five days later we isolated splenocytes for assessment of immune function. We stimulated splenocytes with lipopolysaccharide and 5 days later measured immunoglobulin M synthesis specific for peptidoglycan polysaccharide, a ubiquitous bacterial antigen. We stimulated additional cultures with lipopolysaccharide or concanavalin A to measure B- or T-lymphocyte mitogenic response. Burn injury impaired peptidoglycan polysaccharide-specific immunoglobulin M synthesis compared with sham (p < 0.05), and this impairment was not restored by the administration of dehydroepiandrosterone (p < 0.05). Furthermore dehydroepiandrosterone did not correct the burn-induced impairments of B- and T-cell mitogenic responses (p < 0.05). Our study demonstrates that in this model the administration of dehydroepiandrosterone in vivo does not correct the impairments of humoral or cellular immunity induced by burn injury.

Effect of inhalation injury, burn size, and age on mortality: a study of 1447 consecutive burn patients

The relative impact of inhalation injury, burn size, and age on overall outcome following burn injury was examined in 1447 consecutive burn patients over a five and a half year period. The overall mortality for all patients was 9.5% (138 of 1447). The presence of inhalation injury, increasing burn size, and advancing age were all associated with an increased mortality (p < 0.01). The incidence of inhalation injury was 19.6% (284 of 1447) and correlated with increasing percent total body surface area (%TBSA) burn (r = 0.41, p < 0.01) and advancing age (r = 0.15, p < 0.01). The overall mortality for patients with inhalation injury was 31% (88 of 284) compared with 4.3% (50 of 1163) for those without inhalation injury. Using multivariate analysis inhalation injury was found to be an important variable in determining outcome, but the most important factor in predicting mortality was %TBSA burn (accuracy = 92.8%) or a combination of %TBSA burn and patient age (accuracy = 93.0%). Adding inhalation injury only slightly improved the ability to predict mortality (accuracy = 93.3%). The presence of inhalation injury is significantly associated with mortality after thermal injury but adds little to the prediction of mortality using %TBSA and age alone.

Cultured mouse keratinocyte allografts prime for accelerated second set rejection and enhanced cytotoxic lymphocyte response

It has been reported that cultured keratinocyte (CK) allografts are not rejected in mice, unlike in other species. Several reports have suggested that mouse CK allografts are incapable of stimulating a primary alloresponse, including sensitization of recipients to alloantigens. In this study, we investigated the immunogenicity of mouse CK allografts in vivo by determining whether CK allografts primed for a second set rejection response. First, we grafted mice with either CK allografts, CK autografts, full-thickness (FT) allografts, or no graft at all. We then regrafted mice 4 weeks later with a tail skin allograft. Mice grafted with CK allografts rejected second allografts as rapidly and as vigorously as mice grafted with FT flank allografts. Next, we tested whether CK allograft primed recipients for enhanced CTL responses. We found that mice grafted with CK allografts generated a significantly enhanced CTL alloreactive response after in vitro stimulation. The response was similar to that of mice grafted with FT skin allografts. With evidence that CK allografts primed, we biopsied wounds immediately after CK allografting and, using Western immunoblotting, found that CK allografts had substantial expression of MHC class II antigens in vivo. We conclude from the results of our studies that mouse CK allografts unequivocally prime recipients to alloantigens in vivo and suggest that a possible mechanism for alloantigen priming may be CK allograft expression of MHC class II antigens.

Necrotizing soft-tissue infections

In the realm of clinical practice, this disease entity defies applicability to any classification scheme. Of paramount importance is the early identification of all necrotizing soft-tissue infections. This requires a high index of suspicion, aided by recognition of various risk factors and organ system dysfunction out of proportion to the extent of local signs and symptoms. Expedient, aggressive surgical therapy is imperative: resuscitation, wide débridement, and antibiotic therapy. Once the infection has been controlled, continued supportive care, reconstruction, and rehabilitation can proceed.