Histopathologic effects of cutaneous tape stripping in pigs.

OBJECTIVE: The stratum corneum (SC) is the major barrier to topical absorption of medications. Skin tape stripping (TS) removes the stratum corneum, allowing more rapid absorption of drugs such as local anesthetics. Prior to evaluating TS in human clinical trials, this study was performed to evaluate its immediate and delayed histopathologic effects in swine. METHODS: This was a prospective, interventional, longitudinal, experimental animal study using two isoflurane-anesthetized young swine. Cellophane tape was applied to the skin of clipped swine flanks and peeled away 10, 15, 20, 25, or 30 times. Each level of tape stripping was performed three times in each pig. Full-thickness biopsies were taken at 30 minutes and two weeks later for blinded histopathologic evaluation by a dermatopathologist using randomly ordered hematoxylin-and-eosin-stained tissue sections and conventional light microscopy. The absolute thickness of the cornified layer was measured and compared with normal (unstripped) cornified layer. RESULTS: Tape stripping up to 30 times produces thinning of the SC without detectable changes in the underlying epidermis and dermis at 30 minutes and 14 days post-stripping. The degree of thinning was proportional to the number of tape applications. Complete recovery of the cornified layer was noted at two weeks. There were no adverse effects, such as infection, scarring, or inflammatory cell infiltrates. CONCLUSIONS: Under the conditions studied, TS not only appears safe, but appears to produce no long-term sequelae.

Comparative trial of octyl-cyanoacrylate and silver sulfadiazine for the treatment of full-thickness skin wounds.

A prospective, randomized, blinded, controlled experimental trial was performed in pigs to compare the rates of reepithelialization of 126 full-thickness cutaneous 4-mm punches treated with an octyl-cyanoacrylate spray, silver sulfadiazine, or a dry gauze (controls). Full thickness biopsies were taken 7, 14, or 30 days later for histopathological evaluation of hematoxylin and eosin stained tissue sections by a dermatopathologist. The primary outcome measure was the proportion of wounds completely re-epithelialized at days 7 and 14. Secondary outcomes were the rates of infection, foreign body reactions, and the depth of any resulting cutaneous dells measured with a micrometer. Between-group comparisons were performed with ANOVA or Chi-square tests. Octyl-cyanoacrylate treated wounds re-epithelialized more slowly, as fewer wounds treated with octyl-cyanoacrylate were re-epithelialized at day 7 in comparison with silver sulfadiazine or control wounds (50% vs. 90% vs. 100%, p < 0.001). There were no infections or foreign body type reactions. Amounts of granulation tissue were similar among groups. Octyl-cyanoacrylate wounds were more depressed than silver sulfadiazine wounds at days 7 and 14 yet had similar histopathological characteristics at day 30. We conclude that treatment of small, full thickness cutaneous wounds with octyl-cyanoacrylate results in delayed re-epithelialization and dermal repair in comparison with silver sulfadiazine, yet it does not result in any foreign body-type reaction. However, by 30 days, histopathological wound characteristics were similar in all groups.

Octylcyanoacrylate for the treatment of partial-thickness burns in swine: a randomized, controlled experiment.

OBJECTIVE: To compare re-epithelialization rates of superficial partial-thickness burns treated with octylcyanoacrylate (OCA), silver sulfadiazine (SSD), and dry gauze (controls) in swine. METHODS: This was a prospective, longitudinal, blinded, controlled, experimental trial using anesthetized swine. Sixty-three standardized burns were created by applying an aluminum bar preheated to 80 degrees C for 20 seconds to the flanks of four young pigs. Three equal sets of 21 burns were randomly treated with OCA spray, SSD, or dry gauze (controls). Full-thickness biopsies were taken after 30 minutes and at seven and 14 days for blinded histopathologic evaluation by two dermatopathologists using hematoxylin and eosin staining. The percent of wound re-epithelialization was measured at days 7 and 14, calculated by dividing the length of the regenerated epidermis by the measured width of the biopsy. Analysis of variance (ANOVA) and repeated-measures ANOVA controlling for the individual pig were used for comparisons among groups. This study had 80% power to demonstrate a large between-group difference in percent re-epithelization (alpha = 0.05). RESULTS: There were 63 burns and 126 biopsies. Ten biopsies were excluded for technical reasons. At seven days, there was a significant between-group difference in percent re-epithelialization. Percent re-epithelialization was greatest in the OCA group (65.0%), followed by the SSD group (37.6%), and lowest in the control group (8.8%). At 14 days, all wounds demonstrated near complete re-epithelialization and there was no significant difference in the percent of re-epithelialization among the groups. There was only one wound infection in the OCA group. CONCLUSIONS: Under these study conditions, treatment of partial-thickness burns with OCA spray resulted in a higher percent of re-epithelialization at seven but not 14 days when compared with both SSD and control, with no significant increase in infection rates. Future studies should evaluate the use of OCA for the treatment of burns in humans.

Cardiac myxoma is rich in factor XIIIa positive dendrophages: immunohistochemical study of four cases.

Cardiac myxoma is an enigmatic tumour thought to arise from primitive cardiac mesenchymal cells. Factor XIIIa+ dendrophages are tissue histiocytes that are active in tissue repair and thrombosis. To explore whether factor XIIIa+ dendrophages play a role in cardiac myxoma morphogenesis, we stained four cases with an antiserum against coagulation factor XIIIa (FXIIIa). We also used antibodies recognizing CD34, CD31, and S-100 protein. Samples of valvular endocardium from 12 and 16 week fetuses and two adult autopsies were compared with the four myxomas. All cardiac myxomas had rounded and dendritic FXIIIa+ cells admixed with more numerous CD34+ spindle and stellate myxoma cells. The CD34+ cells formed multicellular syncytia and capillary sprouts. Many of these syncytial structures also expressed CD31 and, to a lesser extent, S-100 protein, strongly in two cases and more focally in two. Fetal subendocardium was composed of CD34+ stellate fibroblast-like cells invested with scattered FXIIIa+ histiocytes; no S-100+ cells were detected. Our findings confirm that cardiac myxomas are composed of CD34+ primitive subendocardial cells. These cells show a capacity for CD31+ endothelial differentiation. In cardiac myxoma, the CD34+ myxoma cells are accompanied by numerous FXIIIa+ dendrophages, the presence of which suggests abnormal organizing thrombus-like differentiation in cardiac myxoma morphogenesis.

Evaluation of a new rapid quantitative immunoassay for serum myoglobin versus CK-MB for ruling out acute myocardial infarction in the emergency department.

STUDY OBJECTIVE: To compare the predictive values of serum myoglobin and creatine kinase (CK)-MB for ruling out acute myocardial infarction in the emergency department. DESIGN: Prospective, observational study. SETTING: University teaching hospital. PARTICIPANTS: One hundred eighty nine consecutive patients aged 30 years and older who presented within 12 hours from onset of chest discomfort, dyspnea, syncope, congestive heart failure, symptomatic dysrhythmia, pulmonary edema, or epigastric pain were entered into the study. Patients with trauma or renal failure were excluded. INTERVENTIONS: Standardized history and physical examination and blood sampling for serum myoglobin (S-Mgb) and CK-MB were done at the time of presentation (T0) and 1 hour later (T1). RESULTS: Using World Health Organization criteria, 22 acute myocardial infarction patients were identified. Mean time from symptom onset to presentation was 3.2 hours. S-Mgb was more sensitive than CK-MB at T0 and T1, 55% versus 23% (P < .05) and 73% versus 41% (P < .05), respectively. Respective specificities of S-Mgb versus CK-MB were 98% versus 99% (P = NS) at T0 and 97% versus 99% (P = NS) at T1. Negative predictive values of S-Mgb versus CK-MB were 94% versus 91% (P = NS) at T0 and 96% versus 93% (P = NS) at T1. The S-Mgb assay yielded quantitative results allowing the difference between the T0 and T1 values to be analyzed. A difference of 40 or more ng/mL between T0 and T1 was considered positive. When using a positive result in either the T0 or T1 value or a difference between the two values of 40 or more ng/mL, the sensitivity of S-Mgb was 91% (P < .05 versus CK-MB), the specificity was 96% (P = NS versus CK-MB), and the negative predictive value was 99% (95% confidence interval for S-Mgb, 97.0 to 100 versus CK-MB, 95% confidence interval, 88.9 to 96.6). CONCLUSION: In the first hour of presentation to the ED, the rapid quantitative assay for S-Mgb was statistically more sensitive than CK-MB and had an excellent negative predictive value for ruling out acute myocardial infarction in patients with typical or atypical symptoms. Due to the relatively small sample size, we could not exclude the possibility that differences in specificity might become statistically significant (beta error) with a larger sample size of acute myocardial infarction patients.