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E F Bernstein

Publications and source records attributed to E F Bernstein.

At least 37 records · Page 2Linked to original sources

8-methoxypsoralen and ultraviolet a radiation activate the human elastin promoter in transgenic mice: in vivo and in vitro evidence for gene induction.

Treatment of skin diseases with the combination of 8-methoxypsoralen and ultraviolet A radiation (PUVA) results in clinical alterations in treated skin that resemble those observed in chronically photodamaged skin. The PUVA-treated patients develop nonmelanoma skin cancers, pigmentary alterations and wrinkling characteristic of sun-induced changes. The major alteration in the dermis of sun-damaged skin is the deposition of abnormal elastic fibers, termed solar elastosis. Up-regulation of elastin promoter activity in dermal fibroblasts explains the excess elastic tissue but not the reason for the aberrant morphology of the elastotic material. In order to study photoaging in an experimental system, we utilized a transgenic mouse line that expresses the human elastin promoter/chloramphenicol acetyltransferase construct in a tissue-specific and developmentally regulated manner. Although UVB radiation has been demonstrated to increase promoter activity in vitro, UVA fails to demonstrate a similar effect at the doses utilized. In this study, we demonstrate the ability of PUVA treatment to up-regulate elastin promoter activity both in vitro and in vivo. These data help to explain the development of photoaging in sun-protected PUVA-treated skin. We attribute the up-regulation of elastin promoter activity in response to PUVA to the formation of DNA photoadducts, which do not occur in response to UVA radiation alone.

Animals↗

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the Ad Hoc Committee, American Heart Association.

BACKGROUND AND PURPOSE: Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. METHODS: A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. RESULTS: The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit. CONCLUSIONS: Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain: stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Arterial Occlusive Diseases↗

A diffusing sphere which delivers homogeneous laser light for use in photodynamic therapy.

Photodynamic therapy (PDT) exploits the selective uptake of a photosensitizer in tumors and other hyperproliferative target tissues, as well as the ability to direct the treatment light beam to a specific region. Since the photodynamic effect depends on light dose, tissue optical properties and photosensitizer concentration, uniform delivery of light is crucial to attain optimal photodynamic effect. Many commonly used methods for delivering laser light during photodynamic therapy, such as a free fiber or microlens, require fiber and laser adjustments to obtain a highly uniform beam. In this study, we test the ability of a diffusing sphere to improve the uniformity of a light field coming from an argon laser coupled to a free fiber, in which no attempt has been made to optimize beam characteristics. Light fields from the free fiber, a microlens and the diffusing sphere are compared for uniformity via light intensity readings. An in vivo comparison between the sphere and the free fiber is also made in guinea pigs given Photofrin-II. The diffusing sphere decreases problems with shielding, allows quick and easy application of light by simply applying the device over the desired treatment area, and optimizes the desired photodynamic effect by producing ad highly uniform beam of light with no necessity to optimize light delivery by vibrating, looping or re-cleaving fibers.

Animals↗

Screening for abdominal aortic aneurysms during lower extremity arterial evaluation in the vascular laboratory.

PURPOSE: The purpose of this study was to evaluate the cost-effectiveness of screening for abdominal aortic aneurysms (AAA) during noninvasive lower extremity arterial examination in the vascular laboratory. METHODS: Over 30 months we screened 531 patients who underwent lower extremity arterial evaluations in the vascular laboratory. The patients had fasted overnight, and, after the regular noninvasive lower extremity arterial examination, the abdominal aorta was screened with B-mode ultrasonography. RESULTS: The aorta was adequately visualized in 475 patients (89%). Mean aortic diameter was 19.6 +/- 4.1 mm at the juxtarenal level and 18.8 +/- 7.2 mm in the lower infrarenal aorta. The aortic diameter was larger in men (p < 0.001) and in smokers (p < 0.001). AAA (diameter greater than 3.0 cm) were identified in 32 patients (6.0% of the 531 patients screened), and 15 of the aneurysms were equal to or larger than 4.0 cm. The best predictors for AAA by logistic regression analysis were male sex (p < 0.005), advanced age (greater than 65 years, p < 0.01), and a history of smoking (p < 0.01). The prevalence of AAA was 6.7% (32/475) in the population in whom the aorta was visualized and 15.2% (19/125) in male smokers over 65 years of age. Aneurysms of 4.0 cm or greater were identified in 3.2% of the entire population screened and 8.8% of male smokers over age 65. Limited aortic scanning prolonged the vascular laboratory examination by an average of 5 minutes. Thus detection of one aneurysm required 83 minutes of scanning time for the whole population studied and 36 minutes of scanning of male smokers over age 65, at a cost of $240 to $553 per aneurysm identified. CONCLUSION: Screening for AAA during lower extremity arterial evaluation in the vascular laboratory addresses a high-risk population, is cost-effective, and should be considered an appropriate and valuable addition to the examination protocol.

Aged↗

Ultraviolet radiation activates the human elastin promoter in transgenic mice: a novel in vivo and in vitro model of cutaneous photoaging.

The major alteration in photoaged skin is the deposition of massive amounts of abnormal elastic material, termed solar elastosis. In previous work, it has been shown that solar elastosis is accompanied by increased abundance of elastin and fibrillin mRNAs and upregulation of elastin promoter activity. Using a transgenic mouse line, which expresses the human elastin promoter, linked to a chloramphenicol acetyltransferase reporter gene, in a tissue-specific and developmentally regulated manner, we investigated the effects of ultraviolet A radiation and ultraviolet B radiation on human elastin promoter activity in vivo and in vitro. Irradiation of mice with a single dose of ultraviolet B radiation (491.4 mJ/cm2) resulted in an increase up to 8.5-fold in promoter activity, whereas a more modest increase of 1.8-fold was measured with ultraviolet A radiation (38.2 J/cm2). In addition, in vitro studies revealed over a thirtyfold increase in elastin promoter activity in response to ultraviolet B radiation (5.5 mJ/cm2), whereas no change was measured in response to ultraviolet A radiation (2.2 J/cm2). These results confirm the role of ultraviolet B radiation in elastin promoter activation in photoaging, and identify ultraviolet A radiation as a contributing factor. This system should serve as a useful in vivo and in vitro model to study cutaneous photoaging, and for testing compounds that may protect against cutaneous photodamage.

Animals↗

Disseminated cutaneous Pseudallescheria boydii.

As increasingly aggressive chemotherapeutic regimens are used to treat malignancy, more patients will become susceptible to various opportunistic pathogens. Specifically, several fungal organisms previously viewed as relatively non-pathogenic are more frequently causing serious disease in these patients. Identification of these organisms is of paramount importance, as some are relatively resistant to standard antifungal therapies. We report a patient with disseminated cutaneous Pseudallescheria boydii, diagnosed from histopathological examination and culture of a skin biopsy specimen. Identification of the organism was achieved shortly before the patient died. Clinicians must be aware of the numerous emerging opportunistic pathogens, which may require special culture techniques for diagnosis and varied or combined modes of therapy.

Adult↗

Systemic lupus erythematosus in patients diagnosed with treatment-resistant acne.

BACKGROUND: Systemic lupus erythematosus (SLE) may involve any number of organ systems and varies greatly in the severity and type of involvement. Cutaneous manifestations of SLE are equally numerous and varied throughout the course of the disease within an individual, as well as varying between patients. Cutaneous manifestations of SLE are frequently the presenting symptoms, typically noted in the classic malar "butterfly" rash; however, other cutaneous patterns are frequently observed. METHODS: We present here two patients who presented with what was thought to be acne refractory to treatment. RESULTS: These patients actually were found to have a facial eruption associated with SLE as confirmed by skin biopsy. CONCLUSIONS: The importance of investigating atypical or treatment-resistant eruptions, especially in patients experiencing other symptoms, is emphasized.

Acne Vulgaris↗

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the ad hoc Committee, American Heart Association.

BACKGROUND AND PURPOSE: Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. METHODS: A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. RESULTS: The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit. CONCLUSIONS: Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. (As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain; stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Aspirin↗

Expression of fibrinolytic genes in atherosclerotic abdominal aortic aneurysm wall. A possible mechanism for aneurysm expansion.

Expansion of atherosclerotic abdominal aortic aneurysm (AAA) has been attributed to remodeling of the extracellular matrix by active proteolysis. We used in situ hybridization to analyze the expression of fibrinolytic genes in aneurysm wall from eight AAA patients. All specimens exhibited specific areas of inflammatory infiltrates with macrophage-like cells expressing urokinase-type plasminogen activator (u-PA) and tissue-type PA (t-PA) mRNA. Type 1 PA inhibitor (PAI-1) mRNA was expressed at the base of the necrotic atheroma of all specimens and also within some of the inflammatory infiltrates where it frequently colocalized in regions containing u-PA and t-PA mRNA expressing cells. However, in these areas, the cellular distribution of the transcripts for t-PA and u-PA extended far beyond the areas of PAI-1 expression. These observations suggest a local ongoing proteolytic process, one which is only partially counteracted by the more restricted expression of PAI-1 mRNA. An abundance of capillaries was also obvious in all inflammatory infiltrates and may reflect local angiogenesis in response to active pericellular fibrinolysis. The increased fibrinolytic capacity in AAA wall may promote angiogenesis and contribute to local proteolytic degradation of the aortic wall leading to physical weakening and active expansion of the aneurysm.

Adult↗

Differential expression of the versican and decorin genes in photoaged and sun-protected skin. Comparison by immunohistochemical and northern analyses.

BACKGROUND: Chronic sun exposure induces numerous changes in exposed skin; the most striking histopathologic change is the massive accumulation of material with the staining characteristics of elastin, termed solar elastosis, in the superficial dermis. Previous studies have identified elastic fibers within areas of solar elastosis, as well as a decrease in collagen content. Recently, the large chondroitin sulfate (CS) proteoglycan, versican, has been identified in the dermis in association with elastic fibers, and the smaller CS proteoglycan, decorin, has been shown to codistribute with collagen fibers. Thus, changes in expression of these CS proteoglycans might be expected in photoaging and may help to explain the clinical alterations of chronically sun-exposed skin. EXPERIMENTAL DESIGN: Immunohistochemical staining and confocal laser scanning microscopy for versican and decorin was performed on paired tissue samples from photoaged and non-sun-exposed skin taken from the same individuals. To investigate versican and decorin mRNA expression, Northern analysis was performed on paired fibroblast cultures derived from tissue explants of photoaged and non-sun-exposed skin. RESULTS: Immunohistochemical staining and confocal laser scanning microscopy revealed a massive accumulation of versican localized to the abnormally large fibers comprising solar elastosis in the superficial and mid-dermis of photoaged specimens. Decorin staining was greatly decreased within the area of solar elastosis. Similarly, changes in mRNA were measured from fibroblast cultures, with a significant increase in versican mRNA in cultures derived from photoaged skin, whereas decorin mRNA levels were significantly decreased in photoaged skin. CONCLUSIONS: This study provides further evidence for the close association of versican with elastic fibers and decorin with collagen fibers, even in the situation of abnormal fiber deposition occurring in photodamaged skin. In addition, changes in versican and decorin immunostaining are accompanied by similar alterations in gene expression.

Aged↗

Changing practice patterns in peripheral arterial disease.

The development of interventional radiologic techniques during the past decade has changed our approach to the treatment of lower extremity peripheral arterial disease (LE-PAD). Balloon and laser-assisted angioplasty, atherectomy (rotary and directional devices), stent implantation, and thrombolysis as well as combinations of all of these approaches, at times with concomitant or secondary surgery, have been used in our institution. A review of our practice patterns during the past 5 years was performed to analyze changing attitudes and results with these newer techniques. All new patients seen in consultation for LE-PAD during three alternate years were reviewed with regard to demographics, initial complaints, initial treatment modality, initial outcome, indications for and results of secondary treatment, and ultimate outcome (at 1 year). The 603 patients were seen during the following three 12-month periods: 1987 to 1988, 1989 to 1990, and 1991 to 1992. An intention-to-treat analysis revealed (1) the number of patients seen for peripheral arterial disease has increased steadily; (2) in the last year more were initially treated with intervention as the primary modality; (3) the results of such catheter-based procedures improved only slightly over this 5-year period, despite our learning curve and the fact that we discarded several ineffective interventional approaches; (4) the fraction of patients primarily operated on and the excellent results of surgery have not changed; and (5) the number of operations for proximal (aortoiliac) disease has decreased markedly, with a corresponding increase in distal reconstructions. The evolution of our current approach to the treatment of LE-PAD is based on this continuing experience.

Angioplasty, Balloon↗

Computed tomography scanning findings associated with rapid expansion of abdominal aortic aneurysms.

PURPOSE: Early repair of abdominal aortic aneurysms (AAA) is particularly appropriate for those that are most likely to expand. Our aim was to define features on computed tomography (CT) scanning associated with subsequent rapid aneurysm expansion. METHODS: We reviewed CT scans of 80 patients with AAA (> 3.0 cm) who underwent CT scanning of the abdomen and pelvis two times, at least 6 months apart, between 1986 and 1992. The aneurysms initially measured 4.4 +/- 0.6 cm, and the mean interval between obtaining scans was 22 +/- 12 months. Clinical variables assessed included age, sex, medical risk factors, underlying cardiovascular and pulmonary diseases, and administration of beta blockers and lipid-lowering agents. Computer-aided measurements on each CT scan section included the maximal and minimal diameters and area of the aneurysm. Dimensions of the luminal thrombus and the arc of aneurysm wall covered by thrombus (TARC). Maximal aneurysm dimensions were related to juxtarenal aortic and second lumbar vertebral body dimensions. RESULTS: Mean aneurysm expansion was 0.26 +/- 0.25 cm/yr. CT scanning variables that correlated significantly with rate of expansion included the mean TARC (r = 0.43, p < 0.001), thrombus volume fraction (r = 0.37, p < 0.001), TARC on the largest aneurysm cross section (r = 0.34, p < 0.01), and thrombus area fraction (r = 0.30, p < 0.01). Rapid expansion (> 0.5 cm/yr) occurred in 15 (19%) aneurysms. The two predictors for rapid expansion on logistic regression analysis were mean TARC (p < 0.005) and the presence of carotid artery disease (p < 0.05). CONCLUSION: An increased AAA thrombus load is associated with a higher likelihood of rapid expansion and should weigh in favor of early surgical repair.

Aneurysm, Ruptured↗

Tufted angioma of the thigh.

Tufted angioma or angioblastoma of Nakagawa is a rare vascular tumor that usually appears in early childhood. It frequently is seen as an erythematous to red-brown, frequently indurated plaque that usually occurs on the trunk or neck. Typically tufted angiomas enlarge for a few years and then cease growing and remain stable. Histopathologic findings are pathognomonic. We describe a patient with a tufted angioma of the thigh who sought treatment for paroxysmal episodes of pain. Treatment with topical clobetasol propionate resulted in a decreased frequency of painful episodes.

Adolescent↗

Enhanced elastin and fibrillin gene expression in chronically photodamaged skin.

Cutaneous aging consists of chronologic aging as well as actinic damage, referred to as photoaging. Most of the morphologic changes associated with an aged appearance result from actinic damage to the skin. The morphologic changes in sun-damaged skin are associated with accumulation of material having the staining characteristics of elastin, known as solar elastosis, in the superficial dermis. Previous studies have demonstrated the presence of elastin within areas of solar elastosis; however, little is known about the mechanisms leading to elastin accumulation in photoaged skin. In addition, fibrillin, the fibrillar component of elastic fibers, has been found in small amounts in solar elastosis. In this study we demonstrate increased elastin mRNA levels in photoaged skin, as well as increased elastin and fibrillin mRNAs in skin explant-derived fibroblasts using Northern hybridizations, compared with controls from sun-protected sites of the same individual. Increased elastin mRNA levels result from transcriptional upregulation of the gene, as demonstrated by transient transfections with a human elastin promoter/chloramphenicol acetyltransferase construct. Elevated mRNA levels were also correlated with increased elastin and fibrillin deposition in paired biopsy specimens from photodamaged and non-sun-exposed skin, as demonstrated by immunohistochemical staining. Thus, approaches to counteract transcriptional activation of elastin gene expression may be useful in preventing the changes associated with cutaneous photoaging.

Aged↗

Comparison of iontophoresis of lidocaine with a eutectic mixture of lidocaine and prilocaine (EMLA) for topically administered local anesthesia.

BACKGROUND: Almost all dermatologic surgery is accomplished using local anesthesia. To make our patients more comfortable, there is a constant search for less painful methods of administering anesthetic agents. Topical EMLA as well as iontophoresis are both useful in this regard. OBJECTIVE: In this study we compared topical EMLA with lidocaine delivered by iontophoresis in a double-blind placebo-controlled trial. Our goal was to assess the degree of anesthesia obtained as well as the relative rapidity of onset. METHODS: A double-blind controlled study was performed on 10 healthy volunteers between 26 and 37 years of age. Three test sites were placed on each forearm. EMLA or a moisturizer control was placed on two of the three test sites on each arm. Each site was wiped free of cream and tested for sensitivity to pinprick 30 and 60 minutes after cream placement. One iontophoretic unit was placed on each forearm. Both units were saturated with anesthesia with the control unit being turned off. Sensitivity to pinprick was evaluated at the iontophoretic sites and one of the EMLA sites 30 minutes after site placement on the subject. The additional EMLA-treated site was tested in the same manner 60 minutes after placement. RESULTS: Both EMLA cream and the iontophoretic unit delivered topical anesthesia greater than the control. Significantly more anesthesia was acquired 1 hour after application of EMLA than was seen 30 minutes earlier. The iontophoretic patch-treated area provided greater anesthesia than the EMLA-treated sites evaluated 30 and 60 minutes after placement. Both modalities provided significant anesthesia when left in place for 60 minutes. CONCLUSION: Both iontophoresis of lidocaine and topical EMLA delivered significant, and sometimes complete, local anesthesia. A greater degree of anesthesia is delivered via iontophoresis after 30 minutes as compared with EMLA left on the skin for 30 or 60 minutes. Both modalities have important and unique advantages and disadvantages. Topical EMLA and iontophoretically delivered lidocaine are both valuable tools for the dermatologic surgeon.

Administration, Cutaneous↗

Healing impairment of open wounds by skin irradiation.

BACKGROUND: Ionizing radiation is frequently used for the treatment of malignancy. Sequelae of therapeutic radiation frequently present clinical problems in the form of poor wound healing and easy injury of treated tissue in response to mild trauma. OBJECTIVE: We describe a radiation-impaired wound healing model in guinea pigs, developed to determine the effect of cutaneous irradiation on wound contraction. METHODS: Guinea pigs were anesthetized and a flap of skin was isolated and treated with x-rays to 18 Gy. Circular wounds of identical size were made in irradiated and control skin, and average wound size was recorded. RESULTS: Our results demonstrate that a statistically significant wound healing deficit is produced in open wounds by surface irradiation of skin. CONCLUSION: Radiation of skin results in slower healing of open wounds, and provides an in vivo system for evaluation of topical dressings and growth factors in radiation-impaired wounds.

Animals↗