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Query: UMLS:C0849640 (skin damage)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of step-up (42----44 degrees sequence) and step-down (44----42 degrees sequence) heating were studied on a transplantable mammary adenocarcinoma of C3H/He mouse. Tumor-bearing legs were immersed in a water bath and the response to hyperthermia was evaluated in terms of the delay in tumor growth. Tumor growth was delayed greatly with increase in the duration of treatment with 44 degrees hyperthermia, whereas with 42 degrees hyperthermia of up to 180 min, tumor growth was delayed only slightly. The effects of step-up heating were similar to those of 44 degrees hyperthermia alone and the response was enhanced by a factor of 0.9-1.1 with the 60-min treatment at 42 degrees followed by treatment at 44 degrees. Thermal resistance developed when the preheating time at 42 degrees was longer than 30 min. On the other hand, the tumor response was markedly enhanced by step-down heating by a factor of 1.8-2.4 with the treatment at 44 degrees followed by 60-min treatment at 42 degrees. Since the enhancement factor for skin damage found previously was similar to that for the tumor, therapeutic gain cannot be expected by the use of these combined heat treatments.
Jpn J Cancer Res 1986 Nov
PMID:Effects of step-up and step-down heating on a transplantable murine tumor. 309 20

It has been reported by the American Petroleum Institute (API) that dermal applications of certain middle distillates of mineral oils can result in high incidences of skin tumours in mice. This was unexpected as the polycyclic aromatic hydrocarbon (PAH) levels in these were below detection limits. To examine the possible role of tissue injury in the induction of tumours, the skin reactions produced by thrice weekly applications of three middle distillates similar to those tested by the API were examined grossly and histopathologically at intervals up to 6 weeks. Various reference materials and oils were used as controls. Preliminary histological examination showed that severe skin damage was present from week 1 onwards in mice treated with the three middle distillates, two of them producing epidermal loss and ulceration. Marked epidermal hyperplasia was produced by all three middle distillates. These findings support the view that regenerative epidermal hyperplasia due to repeated severe skin damage may have exerted a powerful promotional effect in the production of the skin tumours by middle distillates in the API study.
Cancer Lett
PMID:Early changes produced in mouse skin by the application of three middle distillates. 318 34

The occurrence of squamous cell carcinoma of the lid is reviewed with emphasis upon the incidence, clinical presentation, pathophysiology and methods of treatment. Squamous cell carcinoma accounts for about 9% of all eyelid malignancies, although it is frequently over-diagnosed by pathologists and confused histologically with other benign entities. This lesion occurs most commonly in elderly, fair-complexioned individuals with a history of chronic sun exposure and skin damage. In the lids, squamous cell carcinoma shows a variety of clinical appearances although it usually presents as a painless, hyperkeratotic lesion that gradually enlarges and eventually ulcerates. There is a tendency for lower lid and lid margin involvement. This potentially lethal neoplasm is capable of aggressive local spread or metastasis to regional lymph nodes. The development of squamous cell carcinoma is thought to progress through phases of intraepithelial squamous dysplasia and intraepidermal squamous cell carcinoma before invasive squamous cell carcinoma occurs. Various treatment modalities have been advocated including surgical extirpation with histologic control, radiation therapy and cryotherapy.
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PMID:Squamous cell carcinoma of the eyelid. 352 6

In order to evaluate the photoprotective efficacy of sunscreens against the chronic actinic damage, we tested 3 sunscreens for their ability to reduce the induction of unscheduled DNA synthesis (UDS) and to prevent the inhibition of semi-conservative DNA synthesis by medium wavelength ultraviolet (UV-B) radiation in the normal human cultured fibroblasts in vitro. The values obtained are correlated with the sun protection factors (SPF) expressing the erythema inhibition in normal human skin. All sunscreens tested showed a protective effect. The protective factor for the induction of UDS is 10.1 for Spectraban 15 (SPF 15), 3.6 for Spectraban 5.6 (SPF 5.6) and 1.9 for 2.5% Indomethacin solution, whereas the protective factor for the inhibition of semi-conservative DNA synthesis of 15.2, 3.9 and 2.1 for each sunscreen was evaluated. These methods seem to be useful as a screening procedure for the evaluation of sunscreen effectiveness against chronic actinic skin damage including light induced skin malignancies.
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PMID:Sunscreens block the induction of unscheduled DNA synthesis and the inhibition of DNA synthesis by UV-B radiation in normal human fibroblasts. A new way of evaluating sunscreen efficacy in vitro. 387 13

On a few occasions in the past, radiobiological experiments profoundly influenced the practice of radiotherapy. For example, it was shown in the 1920s that animals could be sterilized without damage to the skin of the scrotum if the testes were irradiated in multiple fractions, whereas in a single dose, sterilization was not possible without significant skin damage. These experiments led to the fractionation patterns used in conventional radiotherapy today. Few experiments have had such a dramatic impact, but since World War II, studies with mammalian cells in culture, transplantable animal tumors, and normal tissue systems produced an impressive body of experimental data. Conventional radiotherapy techniques now can be understood in terms of the basic principles of radiobiology. New horizons in radiotherapy are also suggested. These include the following: (1) altered fractionation schedules, including hyperfractionation and accelerated treatment; (2) the selection of groups of patients likely to benefit from neutrons; and (3) The use of hyperthermia alone or as an adjunct to radiation.
Cancer 1985 May 01
PMID:Radiation biology. 391 19

Three hundred fifty albinos in the city of Dar-es-Salaam have been registered at the Tanzania Tumor Centre. Their skin changes were followed for at least 2 years. Chronic skin damage was evident in all albinos by the first year of life; by 20 years, the skin of every subject demonstrated subclinical malignant change, and some had clinical epitheliomas. Untreated, the latter tumors become intractable and disseminate, usually causing death in the third or fourth decade of life. Four clinical stages could be identified, each one associated with distinct pathologic changes: Stage 1, erythema; Stage 2, epidermal atrophy with dermal hypertrophy; Stage 3, solar keratosis; and Stage 4, clinical carcinoma (under 3 cm). It was found that clinical Stage 2 only occurs in those skin areas that show evidence of previous Stage 1 change. Similarly, Stage 3 occurs only in areas that have gone through Stages 1 and 2. Stage 4 cancers were only found in those areas that had gone through all of the three prior stages. During the 2-year period of this study, 104 skin cancers, both early and advanced, were recorded at the albino skin clinic. Thirty-three of the 104 cancers were advanced (over 4 cm in diameter). The median age of the latter group was 31.0 years. Whereas there was no sex bias in the distribution of clinical cancer, 28 of the 33 advanced cancers were in men. Histologically, the great majority of the advanced tumors were squamous cell carcinomas: 29 of 33. There was one melanoma and three basal cell tumors. The predominant site of advanced cancers in the study group was the head and neck region (30 patients); the other three occurred on the trunk, which is generally covered by clothes.
Cancer 1985 Apr 15
PMID:The Tanzanian human albino skin. Natural history. 397 67

In vitro and in vivo experiments were performed to evaluate the parameter of light dose rate as it relates to the efficiency of hematoporphyrin derivative (HPD)-induced photosensitization. Exponentially growing Chinese hamster ovary cells were incubated with HPD (25 micrograms/ml) and were then exposed to red light (630 nm) delivered at different dose rates. A total of five dose rates (0.5, 5.0, 15, 23, and 60 milliwatts/sq cm) were examined following a 1-hr HPD incubation, two dose rates (1 and 20 milliwatts/sq cm) were examined after a 12-hr HPD incubation, and three dose rates (0.4, 4, and 40 milliwatts/sq cm) were examined following a 16-hr incubation and a 30-min serum wash protocol. The effect of light dose rate was determined from cell survival curves obtained by standard clonogenic colony formation assays. Similar levels of cellular toxicity were obtained when cells from each HPD incubation group were treated with equal doses of red light delivered at different dose rates. For in vivo experiments, albino mice were given injections of HPD (7.5 mg/kg) and 24 h later the right hind leg of each mouse was treated with localized red light (630 nm). A total dose of 270 J/sq cm was delivered to the right hind leg at dose rates of 5, 25, or 125 milliwatts/sq cm. The resulting acute skin damage induced by HPD photosensitization was scored over a 30-day period, and skin response curves for the three dose rates were obtained. Comparable levels of damage were induced in each of the three experimental groups. The results obtained from both in vitro and in vivo studies indicate that the photosensitizing efficiency of HPD photodynamic therapy is not affected by nonthermal variations in clinically relevant dose rates of delivered light.
Cancer Res 1985 May
PMID:In vitro and in vivo light dose rate effects related to hematoporphyrin derivative photodynamic therapy. 398 54

Evidence associating malignant melanoma with semiquantitative and questionnaire indicators of past sunlight exposure is presented from a case-control study of 511 patients and 511 matched control subjects in Western Australia. That melanoma is related to sun exposure was supported by associations with actinic skin damage graded by cutaneous microtopography, history of nonmelanotic skin cancer, duration of residence of migrants to Australia, and mean annual hours of bright sunshine received at locations where the subjects had resided. Separate analyses of histogenetic subtypes revealed that Hutchinson's melanotic freckle melanoma had the strongest associations with indicators of sunlight exposure. For superficial spreading melanoma, a specific relationship was observed with age at arrival as against duration of residence in Australia. Migrants arriving before age 10 years appeared to have a risk similar to that of native-born Australians, whereas the estimated incidence in those arriving after age 15 years was around one-quarter of the native-born rate, with arrival at later ages giving no additional advantage. Control subjects arriving in Australia before age 10 years had an increased number of nevi on their arms, suggesting that sun exposure in early life may be a factor in nevus production and, therefore, a determinant of later potential to develop superficial spreading melanoma.
J Natl Cancer Inst 1984 Jul
PMID:Cutaneous malignant melanoma and indicators of total accumulated exposure to the sun: an analysis separating histogenetic types. 658 37

The present study is an attempt to investigate the possibility that ultraviolet irradiation in the presence of pheomelanin may be more harmful to cells than the irradiation in the presence of eumelanin. The effects of UV-visible irradiation upon Ehrlich ascites carcinoma cells in the presence of the melanin isolated from human black hair (eumelanin) or from red hair (pheomelanin) were investigated. Irradiation of these cells was found to produce cell lysis, as observed by leakage of 51Cr from labeled cells and intracellular lactic dehydrogenase from the cells and decrease in cell viability demonstrated by the trypan blue exclusion test. The three parameters were quantitatively parallel to one another under various experimental conditions, namely different periods of irradiation and irradiation in the presence of different concentrations of melanin. The above effects were more pronounced when the irradiation was carried out in the presence of melanin from red hair than in the presence of black-hair melanin. In the absence of either melanin, the irradiation did not produce any significant effect in cell viability or cell lysis. Irradiation of the cells in the presence of red-hair melanin also decreased the transplantability of these cells. These observations clearly show that irradiation of cells in the presence of pheomelanin could produce cytotoxic effects. The present experimental design may have application in the development of in vitro models for the study of UV radiation-induced cutaneous carcinogenesis. The reactions of pheomelanin may be related to the susceptibility of "Celtic" skin to UV radiation-induced skin damage and carcinogenesis.
Cancer Res 1983 Jul
PMID:Effects of ultraviolet-visible irradiation in the presence of melanin isolated from human black or red hair upon Ehrlich ascites carcinoma cells. 685 Jun 26

Treatment of HIV and related malignancies with pharmacologic and biologic agents has not appreciably modified the course of disease. Immunologic impairment remains the critical factor in response. We report the long-term results of a single session of low-flow (0.3 L/min) extracorporeal perfusion hyperthermia on 29 men and 2 women with disseminated Kaposi's sarcoma and profound immunologic impairment. Any antiretroviral drug employed by the patient was stopped 72 hours prior to treatment and withheld during the period of follow-up. Core temperature was raised to 42 degrees C and held for 1 hour with extracorporeal perfusion and ex vivo blood heating to 49 degrees C as the means of temperature control. Of 31 patients, 2 died of complications secondary to treatment (cardiac arrhythmia; CNS bleed). There were two cases of intravascular coagulopathy. Pressure point skin damage may occur despite adequate cushioning. At 30 days posttreatment complete or partial regressions were seen in 20/29 of those treated, with regressions persisting in 14/29 of those treated by 120 days posttreatment. At 360 days, 4/29 maintain tumor regressions with 1 in complete remission (at 26 months). The patient in complete remission remains culture-negative and PCR-negative for HIV. CD4+ counts rose from around 250 to, and remain around, 800 in this man. Selected healed lesions were biopsied to demonstrate tumor absence. Patients were selected for treatment if pretreatment testing of the tumor showed regression in vitro with heat exposure. Analysis of the early and midterm failures showed little sustained rise of the CD4+ cells if presenting total CD4+ counts were below 50 and had been at such low levels for extended periods, although other surrogate markers of HIV activity declined (semiquantitative PCR) during this period and is felt to support the hypothesis of apoptosis proposed in this illness. Analysis of the tumors of the few men not responding demonstrated elevated levels of IL-6 as compared to responders (12 vs < 1 pg/ml). At 120 days 29/31 patients remained alive (expected, 20). At 360 days, 21/31 remained alive (expected, 11). In no patient was HIV activity stimulated with heat exposure. CMV retinitis did clear in some patients treated (both techniques), but treatment alone did not prevent later development of retinopathy. EBV parameters were markedly altered in the short term with heat exposure in some patients. Few patients showed herpes simplex activation. Varicella-zoster virus remitted in some patients. There is utility in the use of systemic hyperthermia to control HIV and related malignancy.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Systemic hyperthermia in the treatment of HIV-related disseminated Kaposi's sarcoma. Long-term follow-up of patients treated with low-flow extracorporeal perfusion hyperthermia. 791 57


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