RESUMEN
Precise determination of burn depth during the immediate postburn period remains an unresolved clinical problem. In an attempt to provide a new clinical option to aid in diagnosis of burn depth, an immunohistochemical marker (antivimentin) was used to examine excisional tissues or serial punch biopsies, or both, in partial-thickness human burn injuries. To test the hypothesis that burn injury continues to progress beyond the first 24 hours, burn depth was assessed by quantitative morphometric analysis in both a partial-thickness porcine burn model and in sequential samples from human patients. Vimentin immunostaining of ubiquitous mesenchymal populations resulted in a precise demarcation between burn eschar and the viable underlying dermis at 1 to 5 days after burn trauma. Porcine wounds showed continuous and significant progression in burn depth during days 1 through 3, but wounds were no deeper on the fourth postburn day. Similarly, 13 of 14 patients showed significant progression in burn depth between 1 to 5 days after burn injury. In conclusion, immunohistochemical staining with an antisera targeted toward a widely dispersed cell population in the dermis can be utilized as an effective tool to confirm the depth of tissue injury during the acute postburn period. Data from our randomly selected patients with partial-thickness burn suggest that burn wounds continue to demarcate for several days.
Asunto(s)
Quemaduras/patología , Vimentina/metabolismo , Adolescente , Adulto , Anciano , Animales , Biopsia con Aguja , Quemaduras/metabolismo , Niño , Preescolar , Modelos Animales de Enfermedad , Femenino , Humanos , Inmunohistoquímica , Puntaje de Gravedad del Traumatismo , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Porcinos , Factores de TiempoRESUMEN
Interstitial collagenase, a matrix metalloproteinase, is known to be actively involved in remodeling of cutaneous tissues including those affected by trauma, neoplasia, and inflammation. Conversely, collagenase activity is blocked by tissue inhibitor of metalloproteinases (TIMP). Because both collagenase and TIMP are rapidly secreted into the extracellular matrix, their sites of synthesis remain ambiguous. To determine the site and sequence of collagenase and TIMP expression in cutaneous wound repair, we examined partial and full thickness excisions of human burn wounds representing days 2 to 34 postinjury. Prominent labeling for collagenase and TIMP was detected in epithelial cells at the burn margin and at the edges of surviving hair follicles and eccrine sweat structures in the wound bed. Within the dermis, cells expressing collagenase and TIMP were at first perivascular in location and later appeared at the interface zone between viable and nonviable dermis. A diversity of cell types including macrophages, fibroblasts, endothelial cells, and keratinocytes appeared to express mRNAs for collagenase and TIMP. Little if any labeling was detected in necrotic regions, in adjacent nonwounded dermis, or epidermis. Our data indicate that collagenase and TIMP are temporally and spatially regulated during cutaneous wound repair.
Asunto(s)
Quemaduras/enzimología , Quemaduras/fisiopatología , Colagenasas/genética , Glicoproteínas/genética , ARN Mensajero/análisis , Cicatrización de Heridas/genética , Adolescente , Adulto , Anciano , Secuencia de Bases , Quemaduras/patología , Niño , Preescolar , Colagenasas/análisis , Femenino , Fibroblastos/química , Fibroblastos/enzimología , Fibroblastos/patología , Glicoproteínas/análisis , Humanos , Hibridación in Situ , Lactante , Macrófagos/química , Macrófagos/enzimología , Macrófagos/patología , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , ARN Mensajero/genética , Piel/química , Piel/enzimología , Piel/patología , Factores de Tiempo , Inhibidores Tisulares de Metaloproteinasas , Cicatrización de Heridas/fisiologíaRESUMEN
Epidermal growth factor (EGF) along with several related peptide growth factors has been shown both in vivo and in vitro to accelerate events associated with epidermal wound repair. EGF and transforming growth factor alpha act by binding to a common EGF receptor tyrosine kinase thereby initiating a series of events which ultimately regulate cell proliferation. This study examined the immunohistochemical localization of EGF receptor (EGF-R) in burn wound margins, adjacent proliferating epithelium, and closely associated sweat ducts, sebaceous glands, and hair follicles. Tissue specimens removed during surgical debridement were obtained from full and partial thickness burn wounds in 32 patients with total body surface area burns ranging from 2 to 88%. In the early postburn period (days 2-4), prominent staining for EGF-R was found in undifferentiated, marginal keratinocytes, adjacent proliferating, hypertrophic epithelium, and both marginal and nonmarginal hair follicles, sweat ducts, and sebaceous glands. During the late postburn period (days 5-16), EGF-R was depleted along leading epithelial margins; however, immunoreactive EGF-R remained intensely positive in the hypertrophic epithelium and all skin appendages. Increased detection of immunoreactive EGF-R and the presence of [125I]EGF binding in the hypertrophic epithelium correlated positively with proliferating cell nuclear antigen distributions. Thus, the presence of EGF-R in the appropriate keratinocyte populations suggests a functional role for this receptor during wound repair. Dynamic modulation in EGF receptor distribution during the temporal sequence of repair provides further evidence that an EGF/transforming growth factor alpha/EGF-R-mediated pathway is activated during human wound repair.
Asunto(s)
Quemaduras/metabolismo , Epidermis/metabolismo , Receptores ErbB/metabolismo , Cicatrización de Heridas , Quemaduras/patología , División Celular , Factor de Crecimiento Epidérmico/metabolismo , Epidermis/patología , Epitelio/metabolismo , Epitelio/patología , Humanos , Hipertrofia , Queratinocitos/metabolismo , Proteínas Nucleares/metabolismo , Antígeno Nuclear de Célula en Proliferación , Factores de TiempoRESUMEN
Thin cortical slices of cynamolgus and rhesus monkey kidney were used to study the renal transport of methotrexate (MTX). In experiments with renal cortical slices, MTX uptake at 25 degrees C was linear over the initial 30 min and was temperature-dependent. The Km was 0.094 mM for MTX uptake at 25 degrees C and Vmax was 0.098 mumol/g of tissue/30 min. In the presence of either 1 mM 2,4-dinitrophenol, p-aminohippurate or acetylsalicylate, MTX uptake was competitively inhibited. 2,4-Dinitrophenol had the greatest and acetylsalicylate had the least inhibitory effect. Folinic acid, folic acid and ouabain produced little or no effect on MTX uptake. MTX efflux from preloaded slices (preincubated with 0.5 mM MTX for 45 min) was a first-order process with T 1/2 of 7.13 +/- 0.86 min. In the presence of vincristine or p-aminohippurate the half-lives for MTX were 15.25 +/- 0.91 and 4.59 +/- 0.47 min, respectively. Thus vincristine, an organic base, was found to augment MTX uptake, due to a reduction in the rate of efflux of MTX from the cortical tissues, whereas p-aminohippurate, an organic acid, was found to decrease MTX intracellular concentration by blocking influx and stimulating efflux. It was concluded that the renal transport of MTX in monkey kidney is mediated predominantly by an organic anion secretory process and that there is probably little or no reabsorptive transport.
Asunto(s)
Ácidos Aminohipúricos/farmacología , Corteza Renal/metabolismo , Metotrexato/metabolismo , Vincristina/farmacología , Ácido p-Aminohipúrico/farmacología , 2,4-Dinitrofenol , Animales , Aspirina/farmacología , Transporte Biológico/efectos de los fármacos , Dinitrofenoles/farmacología , Femenino , Ácido Fólico/farmacología , Cinética , Leucovorina/farmacología , Macaca fascicularis , Macaca mulatta , Masculino , Ouabaína/farmacologíaRESUMEN
The mechanism and localization of renal transport of methotrexate (MTX) were studied in the rhesus monkey and the dog. It was found that in both animals MTX was bound with plasma protein in a range of 50 to 68% varying with the MTX plasma concentration. Paper chromatographic analysis showed that a negligible amount of MTX was metabolized. The excretion of MTX in rhesus monkey was mainly by tubular secretion which was blocked by probenecid, but in the dog a bidirectional transport mechanism for MTX was indicated. Tubular secretion was localized in the proximal tubules, and a tubular reabsorptive process was in the distal section. Simultaneous administration of folic acid blocked the tubular reabsorption of MTX, resulting in an increase of renal excretion. Maximum tubular excretory capacity determination showed that a maximum tubular excretory capacity value of approximately 5 mumol/100 ml of glomerular filtrate was observed in the rhesus monkey at a plasma concentration of 0.07 mM and a value of 2 mumol/100 ml of glomerular filtrate for the dog. Studies with renal cortical slice technique also indicated that the monkey kidney can accumulate greater amounts of MTX than can the dog kidney.