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C Scaletta

Publications and source records attributed to C Scaletta.

12 recordsLinked to original sources
PubMed2001

Ultraweak photon emission in assessing bone growth factor efficiency using fibroblastic differentiation.

Photons participate in many atomic and molecular interactions and changes. Recent biophysical research has shown the induction of ultraweak photons in biological tissue. It is now established that plants, animal and human cells emit a very weak radiation which can be readily detected with an appropriate photomultiplier system. Although the emission is extremely low in mammalian cells, it can be efficiently induced by ultraviolet light. In our studies, we used the differentiation system of human skin fibroblasts from a patient with Xeroderma Pigmentosum of complementation group A in order to test the growth stimulation efficiency of various bone growth factors at concentrations as low as 5 ng/ml of cell culture medium. In additional experiments, the cells were irradiated with a moderate fluence of ultraviolet A. The different batches of growth factors showed various proliferation of skin fibroblasts in culture which could be correlated with the ultraweak photon emission. The growth factors reduced the acceleration of the fibroblast differentiation induced by mitomycin C by a factor of 10-30%. In view that fibroblasts play an essential role in skin aging and wound healing, the fibroblast differentiation system is a very useful tool in order to elucidate the efficacy of growth factors.

Adolescent↗
PubMed2001

Protection against pyrimidine dimers, p53, and 8-hydroxy-2'-deoxyguanosine expression in ultraviolet-irradiated human skin by sunscreens: difference between UVB + UVA and UVB alone sunscreens.

As DNA damage induced by ultraviolet radiation plays an essential role in skin cancer induction, we pursued the measure of several DNA lesions induced by ultraviolet radiation in human skin for determining the efficacy of different topical photoprotectors. Non-exposed skin (buttocks from 20 individuals) was exposed to 10 doses of ultraviolet, which corresponded to three to four minimal erythema doses of solar-simulating radiation, and biopsies were taken at 24 h within the half and one minimal erythema dose sites and a nonirradiated, adjacent control area. We report that even suberythemal doses of ultraviolet radiation are capable of inducing substantial DNA damage, namely pyrimidine dimers, p53 induction, and the DNA base-modified product generated by oxidative stress, 8-hydroxy-2'-deoxyguanosine. All three lesions are induced in a dose-dependent manner. An additional eight individuals were treated with either ultraviolet B or ultraviolet B + ultraviolet A sunblock (sun protection factor 15) and exposed to 71/2 and 15 times the minimal erythema dose on each individual, with biopsies taken at 24 h post-ultraviolet. Pyrimidine dimer and p53 expression were rarely seen in nonirradiated skin but occasional staining was seen in all normal skin for 8-hydroxy-2'-deoxyguanosine. Applications of sunscreens to human skin before irradiation were shown to attenuate erythema but did not completely eliminate all three types of cellular damage when tested up to their sun protection factor 15. Furthermore, ultraviolet B + ultraviolet A sunscreens were less efficient than the ultraviolet B alone formulation for protection against all three lesions. These results suggest that DNA damage assessed in vivo by immunohistochemistry provides a very sensitive endpoint for determining the efficacy or photosensitivity of possible different protective measures in human skin.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Induction of the putative protective protein ferritin by infrared radiation: implications in skin repair.

The modification of ferritin in human skin cells in vitro and in vivo following infrared-A irradiation by immunohistochemical analysis and ELISA were evaluated. In addition, we observed that IR-A is not capable of inducing frank damage to DNA (pyrimidine dimers, p53), induction of oxidative stress proteins (heme oxygenase, nitric oxide, superoxide dismutase, heat shock proteins) or proteases (collagenase, stromelysin, gelatinase) involved in carcinogenesis and photoaging of the skin. in vivo, basal levels of ferritin were heterogeneous for all individuals tested but all showed ferritin to stain precisely in the basal layer of unirradiated epidermis. Following IR-A radiation, the ferritin increase was localized to epidermal tissue and showed an increase from 120 to 220%. Parallel to the in vivo analysis, dermal fibroblasts were cultured from six individuals. Quantitative analysis for ferritin in cultured fibroblasts was assessed by ELISA and increases were seen to be dose-dependent and up to 130% of basal levels of ferritin following infrared-A. Our findings indicate that the putative defense system of ferritin that exists in human skin in vivo can be induced by infrared-A radiation and that these wavelengths may prove to be beneficial for human skin. Importantly, following the same doses of IR-A that induced ferritin levels, there was no alteration seen for nuclear DNA type damage, oxidative stress proteins or proteases involved in the degradation of skin. The increased concentrations of this antioxidant in human skin following acute UV radiation could afford increased protection against subsequent oxidative stress.

Adult↗
PubMed1999

In vivo induction of pyrimidine dimers in human skin by UVA radiation: initiation of cell damage and/or intercellular communication?

Pyrimidine dimers participate as important factors in ultraviolet-induced lethality, mutagenicity and tumorgenicity. Substantial efforts have been made in recent years to understand the induction of pyrimidine photodimers and their repair in human skin cells exposed to low physiological fluences of UV-light. Dimers are known to be efficiently induced after UVC and UVB irradiation, but these photoproducts are also highly induced in DNA isolated from human skin irradiated with UVA. By using a sensitive immunohistochemistry dimer detection assay, we confirm that in vivo UVA radiation induces substantial amounts of these DNA changes in the epidermis; in addition, this technique detects them far into the reticular dermis. A considerable number of these photodimers were also seen in non-irradiated control skin up to two centimeters from the irradiation site. All the lesions persist for at least two days post-irradiation. These results sustain the hypothesis that pyrimidine dimer formation and excision could be a modality of epidermal communication.

Adult↗
PubMed1998

Sunlight and carcinogenesis: expression of p53 and pyrimidine dimers in human skin following UVA I, UVA I + II and solar simulating radiations.

DNA damage by UV radiation plays an essential role in skin cancer induction. We report that even sub-erythemal doses of solar simulating radiation, are capable of inducing substantial nuclear damage, namely pyrimidine dimers and p53 induction in human skin in situ. The quantity and distribution of p53 induced in human skin by UV radiation depended highly on the waveband and dose of UV used. Solar simulating radiation induced very high levels of p53 throughout all layers in epidermal keratinocytes 24 hr following an erythemal dose (230+/-15.9/1000 cells), and the induction followed a dose response. Following UVA I + II and UVA I radiations, p53 expression was approximately half of that seen with equivalent biological doses of solar simulating radiation (63.5+/-28.5 and 103+/-15.9, respectively). Expression of p53 was seen in basal cell keratinocytes at lower doses of UVA, but all layers of the epidermis were affected at higher doses. Pyrimidine dimer induction, however, was seen to be the same for equivalent biological doses of UVA I, UVA I + II and solar simulating radiations, which coincides with previous findings that pyrimidine dimers initiate the erythemal response and are implicated in skin carcinogenesis. When equivalent biological doses of pure UVA are used with no UVB contamination, significant nuclear alterations occur in human skin in situ, which can approach those seen with UVB radiation. Our results suggest that DNA damage assessed in vivo by immunohistochemistry could provide a very sensitive endpoint for determining the efficacy of protective measures, such as sunscreens or protective clothing, against both UVB- and UVA-induced damage in human skin.

Adult↗
PubMed1998

Evidence that ferritin is UV inducible in human skin: part of a putative defense mechanism.

As ferritin has been identified as an important factor in antioxidant defense in cultured human skin cells we evaluated the presence of ferritin in human skin in vivo and the modifications following irradiation with UVA I, UVA I + II, and solar simulating light by immunohistochemical analysis. We report that the putative protective protein ferritin is regularly present in the basal layer of unirradiated epidermis in vivo and that the induction of ferritin was dependent on wavelength and cell type. Following UVA I radiation, ferritin increased both in epidermal and in dermal tissue. The same response occurred, although to a lesser extent, with UVA I + II but did not occur following solar simulating radiation. Quantitative analysis for ferritin in cultured keratinocytes and fibroblasts from seven individuals following each UV spectra were also assessed by enzyme-linked immunosorbent assay. The induction of ferritin by UV was highly dependent on the waveband and cell type. UVA I and UVA I + II radiations induced ferritin expression in dermal fibroblasts up to 260% and 200% over basal levels, respectively. Solar simulating radiation produced only a small induction of approximately 130% over basal ferritin levels in dermal fibroblasts. Ferritin increased in cultured fibroblasts as early as 3 h post-UVA with a peak at 6 h that remained until 48 h; there was no observable qualitative or quantitative increase seen in the undifferentiated cultured epidermal keratinocytes. Our findings indicate that the putative defense system of ferritin exists in human skin in vivo and its induction is dependent on UV spectra and cell type. The increased concentrations of this antioxidant in human skin following acute UV radiation could afford increased protection against subsequent oxidative stress.

Adult↗
PubMed1997

Erythema induction by ultraviolet radiation points to a possible acquired defense mechanism in chronically sun-exposed human skin.

BACKGROUND: It is generally accepted that a UVA-induced erythema is difficult to detect except in the most sensitive individuals. OBJECTIVE AND METHODS: As UVA effects on human skin and skin cells have been shown to depend strongly on anatomical body sites, UVA I, UVA I + II and solar simulator radiations were compared in their ability to induce erythema and melanin pigmentation responses in individuals with skin types I-IV on both previously sun-exposed (arms, forearms, thighs) and nonexposed body sites (buttocks). RESULTS: Erythema induction by UVA I on previously nonexposed skin sites followed a dose response in all skin types which was contrary to the absence of erythema induction seen on previously sun-exposed sites. Melanin expression followed a dose and skin type response and was shown to be more enhanced in previously exposed skin and in skin types III and IV. In contrast, UVA I + II induced erythema on nonexposed skin areas and to a lesser extent on frequently sun-exposed skin. Melanin production by UVA I + II was similar to that seen with UVA I alone in individuals of skin types II and III. Solar simulator radiation was very efficient in erythema induction regardless of previous sun exposure of skin. CONCLUSIONS: We have found that contrary to the widespread opinion that UVA and in particular UVA I could not induce a significant erythema, this waveband is capable of measurable erythema induction on skin nonexposed to sunlight. The diminished erythema induction by UVA I on chronically sun-exposed skin suggests the possibility of a defense mechanism against UVA-induced damage in this tissue.

Adult↗
PubMed1996

Susceptibility of human melanoma cells to oxidative stress including UVA radiation.

Ultraviolet radiation, and in particular UVA (320-400 nm), induces significant oxidative stress to human skin. Ferritin and glutathione have been shown to be among the more important molecules within human skin cells providing protection against this damage, the presence of lower levels of these anti-oxidants giving rise to increased cellular sensitivity to stress. We compared endogenous levels of ferritin and glutathione in human melanoma cells with normal human skin fibroblasts and keratinocytes, also the response of melanoma cells to oxidative stress with fibroblasts and keratinocytes. Ferritin levels were heterogenous in the untreated melanoma cell lines tested and remained the same following oxidative stress (UVA radiation) or hemin treatment. Epidermal keratinocytes were unaffected, as were the melanoma cell lines, but skin fibroblasts showed dose-dependent ferritin depletion. Similar results were seen for glutathione alterations resulting from UVA radiation: melanoma cell lines and epidermal skin keratinocytes remained unchanged following UVA radiation, while skin fibroblasts showed dose-dependent depletion. Our results show that human melanoma cells have low ferritin and glutathione levels, yet are resistant to oxidative stress.

Adult↗
PubMed1996

Expression of intercellular adhesion molecule-1 in UVA-irradiated human skin cells in vitro and in vivo.

Ultraviolet A (UVA) radiation represents an important oxidative stress to human skin and certain forms of oxidative stress have been shown to modulate intercellular adhesion molecule-1 (ICAM-1) expression. ICAM-1 has been shown to play an important part in many immune reactions and the perturbations of this molecule by ultraviolet radiation could have implications in many inflammatory responses. An enhancement immunohistochemical method with avidin/biotin was used for analysing the early effects of UVA radiation on human cell cultures and human skin (340-400 nm). Both in vitro and in vivo data show that ICAM-1 staining in epidermal keratinocytes, which was expressed constitutively, decreased in a UVA dose-dependent manner. The decrease was most noted at 3-6 h following UVA radiation with some ICAM-1 staining returning by 48 h post-UVA. ICAM-1 positive staining in the dermis was specific for vascular structures and was increased 24 h after UVA radiation. Cultured dermal fibroblasts exhibited ICAM-1 staining which increased slightly within 6-48 h post-UVA radiation. As epidermal ICAM-1 expression is depleted following UVA radiation and dermal expression increases due to an increase in the vascular structures, ICAM-1 provides a valuable marker following UVA radiation in human skin that can be readily measured in situ.

Adult↗
PubMed1994

Abnormal keratin 1 and 10 cytoskeleton in cultured keratinocytes from epidermolytic hyperkeratosis caused by keratin 10 mutations.

Epidermolytic hyperkeratosis is caused by mutations of the differentiation-specific keratins K1 and K10. These mutations produce a weakened cytoskeleton that is prone to collapse resulting in cell fragility and lysis. In this study we have analyzed cultured keratinocytes from EHK patients bearing 10R-to-H and 15L-to-S mutations within the 1A segment of the K10 rod domain. Keratinocytes were grown submerged in serum-free medium and induced to differentiate by growing to confluence and increasing the Ca++ concentration in the medium. Cultures were either harvested for mRNA sequence analysis or subjected to immunofluorescence microscopy. Differentiating keratinocytes from these patients were found to express these K10 mutations in their mRNA. Moreover, these cells could be distinguished from normal keratinocytes by their aberrant morphology. EHK keratinocytes frequently exhibited a collapsed perinuclear network of K1/K10 filaments and sometimes peripheral granules of K1 and K10 aggregates, reminiscent of the cells of the suprabasal layers in these patients. This report documents the expression of mutant keratin 10 in cultured EHK keratinocytes.

Base Sequence↗
PubMed1992

Relationship between melanogenesis, glutathione levels and melphalan toxicity in human melanoma cells.

Resistance to alkylating agents has been correlated with cellular levels of reduced glutathione (GSH) and glutathione-S-transferase (GST). GSH is also involved in regulation of melanin synthesis. Therefore, we examined sensitivity to melphalan as a function of differentiation and GSH/GST levels in three human melanoma cell lines. The Me8 cell line, classified as undifferentiated on the basis of cell shape, absence of pigment, insignificant dopa oxidase activity and presence of inhibitors of dopa-melanin formation, showed the lowest GST activity among the cell lines investigated. GLL19 cells exhibited normal differentiation as indicated by the presence of dendrites, typical eumelanosomes, melanin granules and dopa oxidase activity. These cells showed the highest GSH content and the highest GST activity. The JUSO cell line showed incomplete differentiation, and its dopa oxidase and GST activities were intermediate between the Me8 and GLL19 cell lines. The sensitivity of melanoma cell lines to melphalan increased with their degree of differentiation; it was lowest for Me8, intermediate for JUSO and highest for GLL19. Dibutyryl cyclic AMP (dbcAMP) enhanced melphalan toxicity against Me8 cells. Depletion of intracellular GSH with buthionine sulphoximine (BSO) resulted in a three-fold increase in melphalan sensitivity in all three cell lines. Our results indicate that melphalan toxicity is related to cell differentiation and GSH status of melanoma cells. Based on the observed relationship between dopa oxidase, GSH/GST levels and drug toxicity, it is proposed that competition for the GSH pool between quinonoid melanin intermediates and melphalan could diminish drug conjugation and increase cytotoxicity.

Bucladesine↗