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The present study aimed to identify the mechanisms underlying the increase in vascular permeability in mouse skin following irradiation. The left ears of C3H mice were subjected to 2 and 15 Gy of radiation in a single exposure. At 24 h after irradiation, the ears were excised and tissue sections were stained with toluidine blue to assess mast cell degranulation. Vascular endothelial growth factor (VEGF) expression was assessed via immunohistochemistry and western blotting. Approximately 5% (3%-14%) (mean [95% CI]) of mast cells in the skin of control mice were degranulated; moreover, at 24 h after 2 Gy irradiation, this value increased to approximately 20% (17%-28%). Mast cell degranulation by 15 Gy irradiation (32% [24%-40%]) was greater than that by 2 Gy irradiation. Significant differences were observed in mast cell degranulation among the control, 2 Gy and 15 Gy groups (p = 0.012). Furthermore, VEGF-positive reactions were observed in the cytoplasm of scattered fibroblasts in the dermis. In immunohistochemistry tests, VEGF expression at 24 h after irradiation increased slightly in the 2 Gy group compared to that in the control group, whereas no difference in VEGF expression was observed in the 15 Gy group compared to that in the control group. Expression of VEGF in western blots was consistent with that in immunohistochemistry. In conclusion, mast cell degranulation was increased in mouse skin at 24 h after irradiation in a dose-dependent manner. In contrast, VEGF expression was slightly increased following only low-dose (2 Gy) irradiation., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

Infrared neural stimulation has been studied for its potential to replace an electrical stimulation of a cochlear implant. No studies, however, revealed how the technic reliably evoke auditory cortical activities. This research investigated the effects of cochlear laser stimulation from the outer ear on auditory cortex using brain imaging of activity-dependent changes in mitochondrial flavoprotein fluorescence signal. An optic fiber was inserted into the gerbil's ear canal to stimulate the lateral side of the cochlea with an infrared laser. Laser stimulation was found to activate the identified primary auditory cortex. In addition, the temporal profile of the laser-evoked responses was comparable to that of the auditory responses. Our results indicate that infrared laser irradiation from the outer ear has the capacity to evoke, and possibly manipulate, the neural activities of the auditory cortex and may substitute for the present cochlear implants in future., Competing Interests: The authors have declared that no competing interests exist.

Background: Radiation-induced bilateral external auditory canal cancer is an extremely rare disease that has yet to be fully characterized in the clinical literature., Methods: Herein, we present a case study of a 75-year-old man with radiation-induced bilateral external auditory canal cancer. The patient's medical history included left maxillary cancer that had been treated with chemoradiation 19 years earlier and local recurrence with total maxillectomy 10 years earlier. Intracavitary radiation was delivered to the site of postoperative recurrence 8 years before the current presentation. The patient declined radical surgery for the external auditory canal cancer at this time, and a customized combined modality regimen was thus administered., Results: There was no recurrence of cancer for 22 months, to date, after completing chemoradiotherapy., Conclusions: Our finding that radiotherapy can be successfully used for radiation-induced cancer indicates that chemoradiotherapy may be a useful strategy for treating this type of malignancy., (© 2019 Wiley Periodicals, Inc.)

The effects of microcurrent application on the elastic cartilage defects in the outer ear of young animals were analyzed. Sixty male Wistar rats were divided into a control (CG) and a treated group (TG). An excisional lesion was created in the right outer ear of each animal. Daily treatment was started after 24h and consisted of the application of a low-intensity (20μA) continuous electrical current to the site of injury for 5min. The animals were euthanized after 7, 14 and 28 days of injury and the samples were submitted to analyses. In CG, areas of newly formed cartilage and intense basophilia were seen at 28 days, while in TG the same observations were made already at 14 days. The percentage of birefringent collagen fibers was higher in CG at 28 days. The number of connective tissue cells and granulocytes was significantly higher in TG. Ultrastructural analysis revealed the presence of chondrocytes in TG at 14 days, while these cells were observed in CG only at 28 days. Cuprolinic blue staining and the amount of glycosaminoglycans were significantly higher in TG at 14 days and 28 days. The amount of hydroxyproline was significantly higher in TG at all time points studied. The active isoform of MMP-2 was higher activity in TG at 14 days. Immunoblotting for type II collagen and decorin was positive in both groups and at all time points. The treatment stimulated the proliferation and differentiation of connective tissue cells, the deposition of glycosaminoglycans and collagen, and the structural reorganization of these elements during elastic cartilage repair., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: This study examined the effects of age and gender on wideband energy absorbance in adults with normal middle ear function., Method: Forty young adults (14 men, 26 women, aged 20-38 years), 31 middle-aged adults (16 men, 15 women, aged 42-64 years), and 30 older adults (20 men, 10 women, aged 65-82 years) were assessed. Energy absorbance (EA) data were collected at 30 frequencies using a prototype commercial instrument developed by Interacoustics., Results: Results showed that the young adult group had significantly lower EA (between 400 and 560 Hz) than the middle-aged group. However, the middle-aged group showed significantly lower EA (between 2240 and 5040 Hz) than the young adult group. In addition, the older adult group had significantly lower EA than the young adult group (between 2520 and 5040 Hz). No significant difference in EA was found at any frequency between middle-aged and older adults. Across age groups, gender differences were found with men having significantly higher EA values than women at lower frequencies, whereas women had significantly higher EA at higher frequencies., Conclusions: This study provides evidence of the influence of gender and age on EA in adults with normal outer and middle ear function. These findings support the importance of establishing age- and gender-specific EA norms for the adult population.

The objective of the study was to evaluate the 980-nm diode laser in conjunction with corticosteroids in the treatment of ear lobule keloids. Several methods have been described for the treatment of keloid scars, but none of them have been 100% successful. Advances in laser techniques have enabled surgeons to define the most appropriate lasers for use in the treatment of different scar types. The diode laser pulses are delivered interstitially in a single repeated mode in non-overlapping sites using a bare optical fiber, followed by intralesional triamcinolone acetonide injection. The number of sessions varies between two to five for the management of more than 75% of keloid size, with a total success rate of 75% and no recurrence in the follow-up of 12 months. The technique used proved to be effective in the treatment of ear lobule keloids.

Cutaneous contamination by radionuclides is a major concern in the nuclear industry. In case of skin exposure to uranium, no efficient emergency treatment is available to remove the actinide from the skin. For this purpose, we developed a nanoemulsion containing calixarene molecules displaying good chelating properties towards uranium. In this paper, we describe the ability of this formulation to trap uranium and limit its transfer from the cutaneous contaminated site into the blood. Uranium percutaneous diffusion kinetics was assessed with Franz cells over 24 h through intact and excoriated pig ear skin biopsies, after or without application of the nanoemulsion. Uranium distribution in the skin layers was analysed by SIMS microscopy. The results showed that prompt application of the calixarene nanoemulsion allows a 94% and 98% reduction of the amount of uranium diffused respectively through intact and excoriated skin. The formulation is still efficient in case of delayed application up to 30 minutes since the 24 h-uranium transfer through excoriated skin is reduced by 71%. Besides, no accumulation of uranium or uranium-calixarene chelate was observed in the different skin layers. In conclusion, this study demonstrated the efficiency of the calixarene nanoemulsion, which can be regarded as a promising treatment for uranium cutaneous contamination., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objective: To compare the histological changes occurring after three different treatment modalities for telangiectasias., Materials and Methods: Thirty 16-week-old New Zealand white rabbits weighing 2.4-3.1 kg were enrolled in the study. The rabbits were divided into three groups. The group 1 received sclerotherapy, he group 2 received phototherapy, and group 3 received high-power diode laser treatments. All animals were treated on the right dorsal marginal ear vein. Biopsies were taken on days 1, 2, 7, and 30 post-treatment, and histopathogical evaluation was performed., Results: Clinical and histological thrombosis occurred between days 1 and 7 in all groups. Superficial necrosis, neutrophil infiltration, and recanalization were mostly seen in group 3, whereas thrombosis was prominent in groups 1 and 2., Conclusions: All of the methods tested appear to have similar mechanisms of action, but had differing clinical and histological results. Phototherapy and laser treatment are non-invasive and do not require an exact, pinpoint technique, in contrast to sclerotherapy. However, sclerotherapy and phototherapy showed better results, especially with regard to recanalization.

Developing of primary lymphoma of the external auditory canal is excepcional. We describe a 53 years old woman who developed a T cell non-Hodgkin's lymphoma and review literature. She was treated with surgery and chemotherapy and remains disease-free 10 months after the treatment.

Purpose: To investigate the incidence of radiation-induced ototoxicity according to the total dose delivered to specific parts of the auditory system, fractionation, and chemotherapy., Methods and Materials: Records of 325 patients treated for primary extracranial head and neck tumors with curative intent who received radiotherapy between 1964 and 2000 (median follow-up, 5.4 years) were retrospectively reviewed. Reconstructions of the treatment plans were generated to estimate the doses received by components of the auditory system., Results: Radiotherapy-induced morbidity developed in 41.8% of patients (external ear, 33.2%; middle ear, 28.6%; and inner ear, 26.8%). Univariate/multivariate analyses indicate that total dose received by parts of the auditory system seem to be significant, though fractionation and chemoradiation may contribute to the incidence of ototoxicities. Sensorineural hearing loss (SNHL) was observed in 49 patients (15.1%). Univariate and multivariate analyses indicated that age (p = 0.0177 and p = 0.005) and dose to cochlea (p < 0.0001 and p < 0.0001) were significant, and chemoradiation (p = 0.0281 and p = 0.006) may increase the incidence of SNHL. Five-year and 10-year actuarial risk of clinically overt SNHL increased to 37% (p > 0.0001) above doses of 60.5 Gy compared to 3% at doses below 60.5 Gy. For patients treated with adjuvant chemotherapy, clinically overt SNHL increased to 30% compared to 18% in the no-chemotherapy group at 10 years (p = 0.0281)., Conclusion: Radiotherapy toxicity was observed in all parts of the auditory system with median doses for incidence varying between 60 Gy to 66 Gy. Total dose to organ seems to be a significant factor though fractionation and chemo-radiation may contribute to ototoxicities.

Background: A 50% to 80% recurrence rate of earlobe keloids can occur following a simple excision. Many modalities, including radiotherapy, have been suggested to reduce the postoperation recurrence., Objective: The aim of the present study was to determine the efficacy of postoperative radiotherapy by a high dose rate Iridium 192 mould in the prevention of earlobe keloids recurrence., Material and Method: Between March 1999 and March 2003, 22 patients with 24 earlobe keloids were treated by radiotherapy immediately following surgical excision. A dose of 15 Gray in 3 fractions was delivered at a point placed 5 mm from the axis of the Iridium sources., Results: From the 22 patients with 24 keloids who were treated, 15 patients with 16 keloids were followed for a minimum of 6 months. Recurrence occurred in two keloids (12.5%). There were no severe adverse effects., Conclusion: Postoperative radiotherapy by high dose rate Iridium 192 mould was an effective prevention of earlobe keloids recurrence. It was well tolerated and did not present any significant side effects.

Mobile phone users often complain about burning sensations or a heating of the ear region. The increase in temperature may be due to thermal insulation by the phone, heating of the mobile phone resulting from its electrical power dissipation, and radio frequency (RF) exposure. The main objective of this study was to use infrared (IR) camera techniques to find how much each of these factors contributes to the increase in skin temperature resulting from the use of one GSM 900 phone. One subject, a healthy male, took part in the study. He was holding the phone in a normal position when the phone was switched off, when it was switched on but with the antenna replaced by a 50 Omega load to eliminate the RF exposure, and when it was transmitting RF fields. The output power could be fixed, and the minimal and the maximal power levels of the phone were used. The study was designed as a double blind experiment. The changes in temperature after 15 and 30 min of mobile phone use were calculated on the exposed side of the head relative to the unexposed side. The insulation and the electrical power dissipation led to statistically significant rises in the skin temperature, while the RF exposure did not., ((c) 2005 Wiley-Liss, Inc.)

The purpose of this study was to develop an easily accessible technique for the delivery of postoperative radiotherapy for the treatment of earlobe keloids. Forty-seven earlobe keloids were given postoperative radiation using the smallest achievable half field Telecobalt technique. Results showed 41 (87.2%) of treated patients' postoperative scars remained free from recurrent keloid formation. Acute reactions were minimal and patient compliance was excellent. In conclusion, the technique described in this study for the delivery of postoperative radiation to earlobe keloids should be readily available in areas of high prevalence. Results are comparable to previously used radiotherapy techniques.

Despite their particular functional consequences, radiotherapy-induced ear injuries remain under-evaluated and under-reported. These reactions may have acute or late character, may affect all structures of the hearing organ, and result in conductive, sensorineural or mixed hearing loss. Up to 40% of patients have acute middle ear side effects during radical irradiation including acoustic structures and about one-third of patients develop late sensorineural hearing loss (SNHL). Total radiotherapy dose and tumour site seem to be among the most important factors associated with the risk of hearing impairment. Thus, reduction in radiation dose to the auditory structures should be attempted whenever possible. New radiotherapy techniques (3-dimensional conformal irradiation, intensity modulated radiotherapy, proton therapy) allow better dose distribution with lower dose to the non-target organs. Treatment of acute and late external otitis is mainly conservative and includes the anti-inflammatory agents (applied topically and systematically). Post-radiation chronic otitis media and the eustachian tube pathology may be managed with tympanic membrane incision with insertion of a tympanostomy tube (grommet), although the benefit of such approach is controversial and some authors advocate a more conservative approach. In these patients the functional deficit can be alleviated by application of bone conduction hearing aids such as, e.g., the bone anchored hearing aid (BAHA). There is no standard therapy for post-irradiation sudden or progressive SNHL yet corticosteroid therapy, rheologic medications, hyperbaric oxygen or carbogen therapy are usually employed (as for idiopathic SNHL), although controversial data on the efficacy of these treatment modalities have been published. In selected cases with bilateral profound hearing loss or total deafness, cochlear implants may prove effective. Further improvements in radiotherapy techniques and progress in otologic diagnostics and therapy may allow better prevention and management of radiation-related acoustic injury.

Angiolymphoid hyperplasia with eosinophilia is an uncommon, benign, but potentially disfiguring vascular proliferation. Angiolymphoid hyperplasia with eosinophilia commonly affects women in the third decade. Although a benign process, significant morbidity can occur including bleeding, pain, and disfigurement. Several therapies have been attempted including curettage, cryotherapy, retinoids, excision, and various lasers. We report on a case of angiolymphoid hyperplasia with eosinophilia responding to pulsed dye laser therapy (585 nm) (SPTL-1a, Candela Corp, Wayland, Mass).

In a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR(1g)) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day., (Copyright 2003 Wiley-Liss, Inc.)

Repeated trauma to the ear very often results in "cauliflower ear." Many methods have been suggested to prevent an injured ear from demonstrating a cauliflowerlike deformity. The principles of treatment are evacuation of the hematoma, control of the reaccumulation of fluid, and maintenance of the cartilage contour. The authors studied the effect of ionizing radiation on deformed rabbit ears induced by repeated trauma. Twenty ears (10 rabbits) were used in the experiment. The animals were divided into four groups (control, preradiation, low dose, and high dose). Hematoma was produced by pounding the lateral side of the auricle 10 times with a 50-g weight at a height of 15 cm. The thickness of the injured and uninjured sites was measured, and histological analysis was performed for each group. The thickness of the ears of the irradiated groups was significantly less than the control group. The authors think that radiation treatment of repeatedly injured ears could prevent ear deformity, and could possibly be an adjunctive form of management of cauliflower ear in addition to hematoma evacuation and compression therapy.

Objective: To study the role of basic fibroblast growth factor (bFGF) in the repair of irradiation- and surgery-induced auricle trauma., Methods: The bilateral auricles of New Zealand white rabbits were received surgical trauma and beta-active irradiation(90Sr-90Y), bFGF was then applied to the wound. The efficacy of bFGF on wound healing was compared with the control group., Results: On the 10th day after the trauma, the mean epithelalized area was (34.17 +/- 0.37) mm2 and the mean number of microvessels/high power field was (10.25 +/- 2.34) in the treated group, whereas both were (26.25 +/- 0.20) mm2 and (4.38 +/- 0.92) respectivety in the control group. There was a significant difference between the two groups (P < 0.05). On the 7th and 14th days after the trauma, the mean epithelialized area in the treated group was significantly different from that of the control group. The measurement by the image cytometry showed that the treated group had a mean nuclear peak area value of (38.28 +/- 7.23) micron 2 and the mean S-stage cell value of (31.28 +/- 10.35)%, and those of the control group were (28.02 +/- 8.13) micron 2 and (20.14 +/- 9.46)% respectively. There were significant differences (P < 0.05) between them., Conclusion: Application of bFGF can, to a certain extent, accelerate the repair of irradiated and surgically injured soft tissue.

Angiosarcoma (AS) is one of the rarest forms of soft tissue neoplasm. They are considered highly aggressive tumors with a poor prognosis. They range from highly differentiated tumors resembling hemangiomas to anaplastic tumors that are difficult to distinguish from carcinomas. Clinically, the appearance of these lesions varies, so confusion may arise from an initially benign appearance. AS comprise less than 1% of all sarcomas. In these patients, tumor size is an important predictor of survival. In our case, the tumor was located in the outer ear and the patient was treated with surgery, radiotherapy (65 Gy), and chemotherapy (adriamycin). A recurrence one year later was treated with salvage surgery and external carotid artery ligature to control abundant hemorrhage.

The experiments were made to study CO2-laser ability to promote spontaneous formation of nasal septum cartilage. Laser-induced changes in physical and histological characteristics of the cartilage tissue were followed up. Optimal regimens of radiation were selected which allowed to modify cartilage shape without impairment of its morphological and histological structure. In vivo tests were performed on rabbit auricular floor cartilage. The present shape of the cartilage remained stable. It is inferred that laser energy may be a promising tool in plastic ENT surgery.

The temporal bone often falls within the field of radiation for head and neck tumors. Whereas osteoradionecrosis is well recognized as the end-stage complication of radiation to the temporal bone, serious non-osteitic complications can also occur, and these are important because the ear is an organ of special sense. Radiation causes changes in the specialized tissues of the ear that can impair function and influence therapeutic decisions. The purpose of this article is to review the non-osteitic effects of radiation on the ear. A series of cases is presented that illustrate the spectrum of non-osteitic complications of radiation therapy. External canal stenosis, otitis media with effusion, chronic suppurative otitis media with or without cholesteatoma, sensorineural hearing loss, vestibular impairment, and facial nerve paralysis are described. Management should be guided by an understanding of the pathogenesis of these complications. The authors believe that non-osteitic complications of therapeutic radiation to the temporal bone are relatively common and warrant increased recognition.

This retrospective study was conducted to analyze the recurrence of ear lobe keloids in 36 patients after surgical excision followed by radiation therapy. In all the cases keloids were excised and the surgical wound closed primarily. Following surgery, patients underwent 1800 cGy of radiation therapy in three equally divided doses over five to seven days. Most of our patients were young black females who developed keloids secondary to ear lobe piercing. Of the 36 patients followed for a mean period of 5.6 years, we noted only one (2.8%) recurrence. All the patients were followed for a minimum of two years. No serious complications were observed in our series. However, one patient developed radiation dermatitis followed by patchy hypopigmentation. We conclude that surgical excision followed by radiation therapy is a safe and effective method to control keloid recurrence in the ear lobe region.

The phototoxic effects of quinolone antimicrobial agents on mouse auricular skin and retina were examined histologically. Sparfloxacin at 50 or 100 mg/kg, which alone causes no histologic change, was orally administered to albino Balb/c mice, which were irradiated with ultraviolet A for 4 hr immediately after administration. In the auricle, degeneration of basal epidermal cells was sporadically observed at 2 hr (during the irradiation). Foci of slight edema with degenerated fibroblasts were seen in the dermis at 4 hr. Edema and neutrophil infiltration in the dermis became severe up to 96 hr. Initial changes in the retina were observed at 2 hr. Vacuolation of the photoreceptor segments (particularly the inner segment) was occasionally associated with swelling of retinal pigment epithelial cells. The segments became disorganized with time, and the outer nuclear layer showed reduced cellularity. The segments and layer were partially thinned and lost 96 hr later. Enoxacin at 400 and 800 mg/kg induced similar lesions to those of sparfloxacin. Levofloxacin caused similar lesions in the auricle but no change in the retina. The combination of oral administration of quinolone and ultraviolet A irradiation, which never caused apparent morphological changes alone, was shown to be able to induce phototoxic lesions in albino mice. Therefore, this method is thought to be useful to examine morphological changes caused by quinolone phototoxicity.

Both histological assessments and measurements of epidermal and dermal components are used to describe some effects of radiation on wound healing in mouse ear. A pattern of early wound closure followed by wound reopening was seen after doses of about 20 Gy and above. After 10 Gy X rays wound closure was comparable with that in unirradiated wounds but the nature of the tissue repair was different. The results suggested that the severity of radiation damage to epidermis is relatively unaffected by wounding but that the time course of expression of the radiation damage is appreciably accelerated. The observations are discussed in terms of their clinical relevance and of current radiobiological hypotheses.

A study is made of the relationship between early and late damage after irradiation of the feet or ears of rats. In one type of experiment in which large groups of animals were given the same dose, there was a good correlation between the early and late forms of damage. In another experiment, the relationship between these two forms of radiation damage was found to be unaltered by a single dose of X-rays given 8 months earlier. Thus, both types of experiment point to the early and late forms of reaction in the skin of rodents resulting from a common cause. Other relevant experimental data and their relationship to clinical observations are discussed.

The effects of prior heat treatment on the skin reaction produced by a subsequent treatment with combined heat and X-rays were investigated in the mouse ear. Ears were heated by immersion in hot water. The priming heat treatment was always 43.5 degrees C for 40 minutes. Its effect was transient, beginning between 24 and 48 hours after the priming treatment and reaching a maximum at 48 to 96 hours when there was a reduction in the skin response to combined heat and X rays, i.e. it caused a reduction in the thermal enhancement ratio (TER). The effect was lost by 192 hours. At 96 hours after the priming treatment the TER for 30 minutes at 42.5 degrees C or at 43.5 degrees C was reduced by a value equivalent to decreasing the temperature by about 0.4 degrees C. This was equivalent to increasing the heating at 43.5 degrees C required to produce a given enhancement of radiation damage by a factor of 1.4 relative to that required without prior heating. The effect was smaller than induced resistance to damage caused by severe heat treatment alone (i.e. necrosis) and it occurred later. These differences support the concept that two separate mechanisms underlie direct heat necrosis and thermal enhancement of radiation damage.

The response of the mouse ear to hyperthermia was investigated at 7-64 weeks after irradiation with X rays. Thermal sensitivity was increased by 12 weeks after single doses of 18 to 20 Gy but showed no further changes up to 64 weeks after exposure. It is suggested that the increase in sensitivity to retreatment by hyperthermia several months after the initial course of radiation may be related to the turnover time of the tissue. Although there are reports which suggest that prior irradiation, given more than two months earlier, does not affect the response of human skin or superficial tumours to the mild hyperthermic treatment in current clinical use, more aggressive heat therapy may produce unexpectedly severe responses in previously irradiated sites.

A previous study of the mouse ear showed that daily treatment at 43.5 degrees C, either 10 X 20 min or 20 min + 9 X 70 min, induced the same resistance to further heating as was induced by a single treatment of 20 min. The results could be explained in at least two ways: (a) no cells are killed by the heat treatments but thermotolerance is induced; and (b) a proportion of cells is killed by each fraction and the degree of thermotolerance induced in survivors increases as the number of fractions is increased. These two possibilities were tested by measuring the response to X-rays at 24 h after various regimes of fractionated hyperthermia. At this time interval the enhancing effect of a single heat treatment would have decayed, so that radiosensitivity should then be related to the number of surviving cells. Up to 49 daily treatments of 20 min had little effect on radiosensitivity, suggesting that these heating regimes did not cause a significant reduction in the number of basal epidermal cells. A regime of 20 min + 4 X 70 min daily also had little effect but a treatment of 20 min + 9 X 70 min daily increased the radiation response, suggesting that the more severe heat treatment had reduced cell survival to approximately 4 per cent.

The effect of argon laser irradiation on the microvessels of the subcutaneous fat tissue of rabbit's ear placed into Clark's transparent chamber was studied. Capillaries and venules were found to be sensitive to argon laser irradiation; functional disturbances of microcirculation were most distinct. Following laser irradiation an active reconstruction of the microcirculatory bed with the redistribution of the blood stream took place along with destruction of the vascular wall and perivascular inflammation.

The present investigation demonstrates cartilage healing in experimental defects in rabbits ears. The authors confirm the importance of the presence of the perichondrium. Ears X-irradiated with disages of 2 000-4 000 R show a reduced healing capacity as compared with control ears.

Photoallergic dermatitis was induced in the mouse following the systemic administration of quinidine in combination with UVB and UVA. The reaction was recorded as ear wet weight, ear thickness and tail wet weight. Statistical calculations showed ear wet weight to be the most sensitive evaluation technique. By varying the quinidine dose administered in induction (2.5-100 mg/kg) and challenge (10-100 mg/kg), dose-response conditions were established. It was shown that the induction dose necessary to obtain a statistically significant reaction was considerably lower than the minimal challenge dose (25 mg/kg). This method is well suited for studies of the dynamics of the induction and elicitation phases of systemically induced photoallergy.