GSM phone signal does not produce subjective symptoms

The influence of pulsed radiofrequency (RF) electromagnetic fields of digital GSM mobile phones (902 MHz, 217 Hz pulse modulation) on subjective symptoms or sensations in healthy subjects were studied in two single-blind experiments. The duration of the RF exposure was about 60 min in Experiment 1 and 30 min in Experiment 2. Each subject rated symptoms or sensations in the beginning of the experimental session and at the end of both the exposure and the nonexposure conditions. The symptoms rated were headache, dizziness, fatigue, itching or tingling of the skin, redness on the skin, and sensations of warmth on the skin. The results did not reveal any differences between exposure and non-exposure conditions, suggesting that a 30-60 min exposure to this RF field does not produce subjective symptoms in humans.     

Continued antigen stimulation is not required during CD4(+) T cell clonal expansion

Peptide Ag initiates CD4(+) T cell proliferation, but the subsequent effects of Ag on clonal expansion are not fully known. In this study, murine CD4(+) T cells were labeled with the fluorescent dye CFSE and were stimulated with specific peptide Ag. Activation occurred, as CFSE-associated fluorescence was reduced 2-fold with each cell division. Separation of proliferating cells based upon CFSE fluorescence intensity showed that daughter cells from each cell division proliferate even after removal of Ag. A limited exposure (2 h) to peptide programmed the cells to proliferate independently of Ag. Although not required for cell division, Ag increased the survival of proliferating cells and increased the total number of cell divisions in the expansion process. These results indicate that Ag exposure begins a program of cell division that does not require but is modified by further TCR stimulation.     

Pugnose eels, Simenchelys parasiticus (Synaphobranchidae) from the heart of a shortfin mako, Isurus oxyrinchus (Lamnidae)

The body depth of crucian carp, Carassius carassius, increases in the presence of predator fish, thereby decreasing the vulnerability of crucian carp to predation. This phenotypic change is mediated by chemical signals, and is believed to result from a piscivorous diet of predators. We have shown that exposure to a piscivorous predator is insufficient to induce growth changes in crucian carp, since water from northern pike, Esox lucius, fed Arctic charr, Salvelinus alpinus, does not induce a change in crucian carp morphology, while water from pike fed crucian carp does. The determining factor is a chemical signal from the skin of crucian carp, as demonstrated by exposure to skin extracts from conspecifics. We suggest that alarm substances from conspecifics, expressing primer pheromone effects, are the most likely candidates for induction of the phenotypical changes.     

Expanded Flap to Repair Facial Scar Left by Radiotherapy of Hemangioma

This study explored the feasibility and clinical efficacy of expanded flap to repair facial scar left by radiotherapy of hemangioma. From March 2000 to April 2011, 13 cases of facial cicatrices left by radiotherapy of hemangioma have been treated with implantation surgery of facial skin dilator under local anesthesia. After water flood expansion for 1–2 months, resection of facial scar was performed, and wound repairing with expansion flap transfer was done. Thirteen patients were followed up from 5 months to 3 years. All patients tolerated flap transfer well; no contracture occurred during the facial expansion flap transfer. The incision scar was not obvious, and its color and texture were identical to surrounding skin. In conclusion, the use of expanded flap transfer to repair the facial scar left by radiotherapy of hemangioma is advantageous due to its simplicity, flexibility, and large area of repairing. This method does not affect the subsequent facial appearance.     

Most common skin tumours in correlation with solar ultraviolet radiation in the area of West Herzegovina

Incidence rate of skin tumours, both, non-melanoma and melanoma, is increasing nowadays. Various etiological factors are of relevance for the occurrence of the diseases. The solar radiation, as well, long-term exposure to ultraviolet (UV) radiation, have the greatest impact on development of these skin tumours. Non-melanoma skin tumours, Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC), are the most common skin tumours in humans, and usually develop on the chronically photo-exposed areas. As for the Malignant Melanoma (MM), one of the most aggressive skin tumours, the exposure to solar radiation also plays an important role. This study investigates the correlation between the skin tumours and UV radiation in the area of West Herzegovina, on the sample of 1676 patients. It presents the occurrence of skin tumours in the period from 1997 to 2003. The study investigates the incidence and the risk factors separately for every skin tumour which can be etiologically related to the occurrence of skin tumours and UV radiation: occupation, exposure to UV radiation, skin type, and family history on malignan tumours within the patient's family. The exact incidence rate of non-melanoma and melanoma skin tumours in Bosnia and Herzegovina is still unknown, for the reason that the united National Cancer Register does not exist yet.     

Effect of menthol on human temperature sensitivity

Application of 1% methol, which, along with cold, activates specific thermosensitive ionic channels, changes the number of functioning cold receptors on the skin of the forearm similarly to the cold exposure test; however, it does not affect the number of heat receptors and does not significantly change the threshold of cold sensation. Group variants of responses to menthol that indicate individual differences in the sensitivity of skin receptors to the effects of methol and cold have been found. The results obtained give grounds to suggest that, from the variant of response to menthol (a decrease, increase, or absence of changes in the number of functioning cold receptors 5 min after menthol application), it is possible to predict specific features of response to cold.     

Alterations in lymphocyte homing patterns within mice exposed to ultraviolet radiation

This report presents the results of an investigation designed to establish whether exposure of mice to ultraviolet radiation (UVR) is capable of influencing the factors that control the distribution of lymphoid cells in vivo. We found that such exposure resulted in a dramatic and long-lasting increase in the tropism of peripheral lymph nodes for circulating lymphoid cells. Termination of UVR exposure did not result in a reversal of this phenomenon. Since an increase in lymphocyte migration into the lymph nodes of UVR-exposed mice was apparent within 2 hr of infusion of the radiolabeled cells, we conclude that the homing assay data reflect a relatively increased binding of circulating lymphocytes to high endothelial venules (HEV) within the lymph nodes of irradiated animals. A histologic analysis of skin from UVR-exposed mice established that the dermal microvasculature had expanded in terms of size and number of vessels, a condition that also does not completely reverse after the termination of treatments. In spite of the increase in dermal microvasculature, very few inflammatory cells were detected in the irradiated skin site. These observations support our conclusion that the enhanced traffic of lymphocytes into peripheral lymph nodes of UVR-exposed mice occurs primarily via lymphocyte-HEV interactions rather than afferent drainage of the irradiated skin.     

Evidence that ultraviolet light-induced DNA replication death of recA bacteria is prevented by protein synthesis in repair-proficient bacteria

The ultraviolet light (UV) survival curve of Escherichia coli WP10 recA trp is almost biphasic, with a greatly reduced shoulder but demonstrating a transition to a decreased slope with increasing fluences, indicating the presence in the culture of a low frequency of resistant cells. Treatment of the culture with chloramphenicol before UV exposure brought almost all of the cells to a high degree of UV resistance, by bringing them to the end of their DNA replication cycle. The survival curves of the repair-proficient E. coli WP2 trp showed a similar pattern with chloramphenicol treatment or tryptophan starvation before UV exposure, but only if protein synthesis were blocked by chloramphenicol for 60 min after UV exposure. The results suggest that when recA/lexA-regulon induction is prevented, either by the recA mutation or by inhibition of protein synthesis after UV exposure, death occurs unless the cells are in the resistant state characteristic of bacteria at the end of their DNA replication cycle. With repair-proficient bacteria treated before UV exposure with chloramphenicol, when protein synthesis is not blocked after UV exposure, a marked expansion of the shoulder occurs because of the function of another resistance-conferring mechanism. This mechanism also depends on the recA+ gene since expansion of the shoulder does not occur in recA bacteria when protein synthesis is inhibited before UV exposure.     

Long-term cold adaptation in the rat

1. To determine whether long-term cold exposure induces insulative adaptation in the rat, two groups of eight adult animals each were exposed to 4 and 25 degrees C, respectively, for 18 months. 2. At any ambient temperature between -5 and 30 degrees C, the cold adapted animals had a higher rate of oxygen uptake, and higher unfurred skin temperatures than the controls. 3. At ambient temperatures below thermoneutrality, whole body thermal resistance increased continuously in both groups of animals. 4. It is concluded that long-term exposure does not induce insulative adaptation, and that thermal resistance is not maximal at the lower critical temperature.     

Long-term histopathologic evaluation of human expanded skin.

Forty-two patients operated on by skin expansion have been contacted after a mean time of 25 months from the last surgery. Two biopsies have been taken from the expanded area of each patient. In 12 patients it has been possible to obtain a similar sampling from the opposite, nonexpanded area of the body. The samples underwent optic microscopy and cell kinetic and DNA content investigations. The epidermal structure of the followed-up skin, compared with the skin of the opposite side of the body, looks normal. The mitotic activity of the epidermal cells has returned to the values of preexpanded skin. The dermis shows a low degree of elastosis and zonal fragmentation of elastic fibers. The hypodermis, where the expander capsule was removed during the last surgery, does not show an accentuated fibrosis.     

Cellular immunity in gnotobiotic primates induced by transfer factor.

Human dialyzable transfer factor (TF) was found capable of inducing in vivo (skin test) and in vitro blastogenesis) cellular immunity in gnotobiotic nonhuman primates. Because the animals were gnotobiotic (germ-free) and had not been skin tested previously, these data support the hypothesis that induction of cell-mediated immunity in recipients of TF does not require a “priming” exposure to specific and/or cross-reacting antigens, and that this induction may be due to an antigen-specific informational effect of TF.In addition, these results support the antigenic specificity of TF, in that recipient primates developed cellular reactivity only against donor “positive” but not against donor “negative” antigens.     

Metabolic changes in rat skin during preservation and storage in glycerol buffer at -196 degrees C.

The penetrating cryoprotective glycerol dissolved in different concentrations in buffer medium effectively protects skin tissue against freeze-thaw injury when progressively cooled to ?196 °C followed by a fast warming-up rate. Upon incubation of the tissue after storage, the incorporation of [2-¹⁴C]glycine into the proteins, of [6-³H]thymidine into DNA, and α-[1-¹⁴C]aminoisobutyric acid transport through the cell membrane are reduced compared to freshly incubated skin. An essential loss in metabolic activity occurs during exposure of the skin to the preserving buffer. Although the length of storage does not seem to affect the final viability, the actual freezing and thawing procedures are particularly damaging to tissue already injured by previous exposure to buffer containing cryoprotective agents.     

The skin of adult rainbow trout is not a significant site of ammonia clearance from the blood

We hypothesized that the skin acts as an extrabranchial route for ammonia excretion in adult rainbow trout (Oncorhynchus mykiss) following high environmental ammonia (HEA) exposure. Trunks of control or HEA-exposed trout were perfused with saline containing 0 or 1 mmol l⁻¹ NH₄⁺. Cutaneous ammonia excretion rates increased 2.5-fold following HEA exposure, however there was no difference in rates between trunks perfused with 0 or 1 mmol l⁻¹ NH₄⁺. The skin is therefore capable of excreting its own ammonia load, but it does not clear circulating ammonia from the plasma.     

An Axisymmetric Computational Model of Skin Expansion and Growth

Skin expansion is the principal technique used in plastic surgery to repair large cutaneous defects, typically after tumour removal, burn care, craniofacial surgery and post-mastectomy breast reconstruction. It allows a gain of new tissue by means of gradual expansion of a prosthesis, surgically implanted beneath the patient’s skin. Nevertheless, wide clinical use is not supported by a deep quantitative knowledge of the phenomena occurring during the expansion. A finite element model of the skin expansion was developed to evaluate the stresses and the strains of the skin due to the expander inflation and validated by proper in vitro experiments; furthermore, a growth model based on the mechanical stimulus was implemented to estimate the skin area gain. The developed computational approach, composed of the skin expansion model interaction and the growth law, proved its validity to investigate skin expansion phenomena: its use suggests a new predictive tool to optimize clinical procedures and the expander devices’ design.     

Nipple connective tissue and its development: insights from the K14-PTHrP mouse

Parathyroid hormone-related protein (PTHrP) regulates a wide variety of developmental processes. Keratin 14 (K14) promoter-mediated overexpression of PTHrP in the epidermis during development converts the entire murine ventral skin to hairless nipple-like skin. In this report, we characterize the morphology and processes that influence the development of nipple connective tissue. The connective tissue of the nipple displayed increased levels of proteoglycans, and collagen bundles with atypical morphology, as well as increased numbers of mast cells, capillaries, nerve fibers and dermal melanocytes. The unique characteristics of nipple connective tissue were not present until mice reach 3-4 weeks of age. The adult male K14-PTHrP mouse has a less dramatic ventral skin phenotype, and does not manifest a nipple-like dermis. Ovariectomy or orchiedectomy prior to sexual maturity had no impact on the ventral skin of the male or female K14-PTHrP mice, but exposure to androgens in utero repressed many of the nipple-like characteristics in the ventral skin of the female K14-PTHrP mice.     

The CCN1 (CYR61) protein promotes skin growth by enhancing epithelial‐mesenchymal transition during skin expansion

The skin expansion technique is widely used to induce skin growth for large‐scale skin deformity reconstruction. However, the capacity for skin expansion is limited and searching for ways to improve the expansion efficiency is a challenge. In this study, we aimed to explore the possible mechanism of skin expansion and to find a potential therapeutic target on promoting skin growth. We conducted weighted gene coexpression network analysis (WGCNA) of microarray data generated from rat skin expansion and found CCN1 (CYR61) to be the central hub gene related to epithelial‐mesenchymal transition (EMT). CCN1 up‐regulation was confirmed in human and rat expanded skin and also in mechanically stretched rat keratinocytes, together with acquired mesenchymal phenotype. After CCN1 stimulation on keratinocytes, cell proliferation was promoted and partial EMT was induced by activating β‐catenin pathway. Treatment of CCN1 protein could significantly increase the flap thickness, improve the blood supply and restore the structure in a rat model of skin expansion, whereas inhibition of CCN1 through shRNA interference could dramatically reduce the efficiency of skin expansion. Our findings demonstrate that CCN1 plays a crucial role in skin expansion and that CCN1 may serve as a potential therapeutic target to promote skin growth and improve the efficiency of skin expansion.     

Transfer of cell-mediated hyperacute rejection reaction: The role of active sensitization

The transfer of lymph node cells draining graft sites of allogeneic murine skin results in adoptive immunization of syngeneic recipients, as per hyperacute rejection of allogeneic test skin grafts. The transfer of spleen cells from mice sensitized by i.p. injection of allogeneic cells does not have this result unless the cells undergo a secondary in vitro sensitization. The resultant hyperacute rejection is due in part to adoptive immunization via the spleen cells primed during the in vivo sensitization and rendered transfer effective by the in vitro exposure; in part it is due to active sensitization by carried-over antigen from the in vitro exposure. It follows that the transfer effect of spleen cells sensitized in vivo and in vitro is only in part abrogated by exposure to α-Thy. 1 serum and complement.     

Intraoperative tissue expansion in rhytidectomy revisited

Intraoperative tissue expansion is an adjunct that has been used during rhytidectomy to rejuvenate the face and neck. This technique has been thought to allow for additional skin resection and, thus, increased skin tightening during rhytidectomy. The stretch of the skin by expansion should allow for additional skin resection before closure. Also, when the force of the underlying expander is removed, the expanded skin would recoil and the advancement of the flap should become tighter, with improved results. The technique achieved some popularity a few years ago but has received little recent attention. In this study, the authors attempted to compare face-lift results of adjunctive intraoperative tissue expansion during rhytidectomy with similar techniques without intraoperative expansion. The results of 50 female patients who underwent rhytidectomy for midface rejuvenation by a single operating surgeon composed the study group. Twenty-five of the patients had undergone rhytidectomy that addressed the cheek, chin, and neck areas without expansion (nonexpanded rhytidectomy group). The other 25 patients (expanded rhytidectomy group) had adjunctive intraoperative tissue expansion performed with the rhytidectomy. A tissue expander was temporarily placed beneath the rhytidectomy flaps on each side and expanded in a standard manner before final skin resection and closure. Frontal and lateral photographs were evaluated by 54 examiners. Preoperative and postoperative photographs of the 50 patients were viewed side-by-side by the examiners. The patients were presented in blind fashion and random order. The examiners graded the results of each patient on a scale of improvement from 1 to 10, with 10 being the maximum level of improvement. The scores were recorded and statistically evaluated by using the two-sample test. Evaluation of the examiners' scores showed that the mean rating given to patients in the expanded rhytidectomy group was 5.07 (SD = 1.12). The mean rating for the nonexpanded rhytidectomy group was 5.27 (SD = 1.57). When the two groups were compared using the two-sample test, the difference between the two was not statistically significant (p = 0.6127). Intraoperative tissue expansion as an adjunct to rhytidectomy did not result in improved facial rejuvenation in this patient series. The authors' impression is that the benefits of tissue expansion do not justify the added expense, time, and risks associated with using tissue expansion during rhytidectomy.     

Maintenance of distinct melanocyte populations in the interfollicular epidermis

Hair follicles and sweat glands are recognized as reservoirs of melanocyte stem cells (MSCs). Unlike differentiated melanocytes, undifferentiated MSCs do not produce melanin. They serve as a source of differentiated melanocytes for the hair follicle and contribute to the interfollicular epidermis upon wounding, exposure to ultraviolet irradiation or in remission from vitiligo, where repigmentation often spreads outwards from the hair follicles. It is unknown whether these observations reflect the normal homoeostatic mechanism of melanocyte renewal or whether unperturbed interfollicular epidermis can maintain a melanocyte population that is independent of the skin's appendages. Here, we show that mouse tail skin lacking appendages does maintain a stable melanocyte number, including a low frequency of amelanotic melanocytes, into adult life. Furthermore, we show that actively cycling differentiated melanocytes are present in postnatal skin, indicating that amelanotic melanocytes are not uniquely relied on for melanocyte homoeostasis.     

Increased survival and vascularity of random-pattern skin flaps elevated in controlled, expanded skin

Controlled clinical tissue expansion, a new technique of providing donor tissue, results in an increase in surface area of expanded skin. The aim of the present study was to determine the effect of controlled tissue expansion on the surviving lengths of random-pattern skin flaps elevated in expanded tissue. In five pigs the surviving lengths of flaps raised in skin expanded for 5 weeks using a 250-cc rectangular Radovan-type tissue expander were compared with the survival lengths of flaps elevated in tissue in which a similar prosthesis was not expanded, bipedicle flaps delayed for 5 weeks, and control acutely raised random-pattern flaps. The expanded flaps had a mean increase in surviving length of 117 percent over control flaps, which was statistically significant. The delay flaps had an increase in survival of 73 percent over control flaps, which was also statistically significant. There was no significant difference in survival between expanded flaps and delayed flaps. Morphologic studies using radiographic techniques on one pig demonstrated increased vascularity with tissue expansion. The results of this work demonstrate that in addition to providing increased surface area with controlled expansion, flaps raised in expanded skin have a significantly augmented surviving length. The mechanism for this increased vascularity with expansion is not known at this time, but it may be due to physical forces associated with expansion acting as a stimulus for angiogenesis.