PubMed Health⌕ Search

Biomedical subjects

Claes D Enk

Publications and source records attributed to Claes D Enk.

12 recordsLinked to original sources
PubMed2006

Role of antioxidants in prevention of pyrimidine dimer formation in UVB irradiated human HaCaT keratinocytes.

The objective of the present study was to study the role of reactive oxygen species (ROS) in UVB induced cyclobutane pyrimidine dimer (CPD) formation in human keratinocytes, and to examine the modulating activity of low molecular weight antioxidants. To demonstrate the involvement of ROS, we examined the protective capacity of alpha-tocopherol, tempamine, and diethyldithiocarbamate (DDC) on CPD formation in intact cells and naked DNA. HaCaT cells and naked DNA in water solution were irradiated with UVB in the presence of the antioxidants and CPD was determined by ELISA. We found that all three antioxidants provided protection against UVB induced CPD formation. The protection was observed in intact cells only and not in naked DNA. Since some of the tested antioxidants do not possess UV absorbing qualities, our findings suggest that in a cellular environment ROS play a role in CPD formation.

Antioxidants↗
PubMed2006

Porphyra-334, a potential natural source for UVA protective sunscreens.

The mycosporine-like amino acid (MAA), porphyra-334 (lambda(max) = 334 nm; epsilon = 42,300 M(-1) cm(-1)), was isolated from the aquatic cyanobacterium Aphanizomenon flos-aquae (AFA) and its structure was verified by spectroscopic methods. The UVA absorption properties of the crude methanolic extract were determined against two commercial sun care products in terms of mean critical wavelength, mean UVA/UVB ratios and UVA protection category (Boots the Chemists, Ltd.). The crude methanolic extract from AFA exhibited maximum UVA protection comparable to that determined for Boots SPF 4.

Aphanizomenon↗
PubMed2006

Ultraviolet A-1 as a treatment for ulcerative lichen planus of the feet.

Ulcerative lichen planus of the feet is a rare variant of lichen planus characterized by the constellation of a chronic bullous and ulcerative eruption limited to the feet, atrophy of involved skin and nails, and cicatricial alopecia. Only split-thickness skin grafting has here to been documented to be effective. We here report a case with ulcerative lichen planus of the feet successfully treated with medium-dose ultraviolet A-1.

Aged↗
PubMed2005

The region of 150 kb telometic to HLA-C is associated with psoriasis in the Jewish population.

The HLA-Cw*0602 has been associated with psoriasis in different ethnic groups. But, it remains unclear whether HLA-C is the PSORS1 gene (the psoriasis gene in the MHC). Thus, several case-control studies have been performed in order to investigate whether HLA-C itself determines the susceptibility to the disease. We studied 59 Jewish patients with type I psoriasis and 79 matched controls. Polymorphic genes and markers from HLA-B (centromeric to HLA-C) to the corneodesmosin (CDSN) gene (telomeric to HLA-C) were genotyped in order to determine their contribution to the susceptibility to psoriasis. Neither HLA-Cw*0602 nor the allele CDSN*TTC were significantly associated with psoriasis with the size of the sample studied. The genes and markers telomeric to HLA-C such as the microsatellite C1_4_4 (OR = 2.6, 95% CI = 1.4-4.7, p(c) = 0.018) the octamer transcription factor (OTF)-3 gene (OR = 2.6, 95% CI = 1.6-4.3, p(c) = 0.0001) and the alpha-helix coiled-coil rod homologue (HCR) gene (OR = 2.5, 95% CI = 1.3-4.5, p(c) = 0.004), however, were associated with the disease. These results suggest that a major psoriasis susceptibility gene is likely to be located within a region of 150 kb telomeric to HLA-C and centromeric to the CDSN gene.

Adolescent↗
PubMed2004

Molecular detection of MART-1, tyrosinase and MIA in peripheral blood, lymph nodes and metastatic sites of stage III/IV melanoma patients.

Melanoma lesions that develop in the same patient at different times or simultaneously at different locations may differ antigenically, because malignant melanoma is heterogeneous in terms of its biological, immunological and metastatic properties. The objective of this study was to characterize the molecular profiles of melanoma cells in peripheral blood, lymph nodes and metastatic tissues, employing the messenger RNA (mRNA) expression of tyrosinase, melanoma-inhibiting activity (MIA) and melanoma antigen recognized by T cells-1 (MART-1) as markers. Samples of cells propagated from metastatic sites were obtained from 17 stage III/IV melanoma patients and assayed by reverse transcriptase-polymerase chain reaction (RT-PCR), using specific primers for each marker. In eight patients, marker profiles were analysed in simultaneously obtained specimens of peripheral blood, lymph nodes and metastatic tissues originating from the same patient. Tyrosinase, MIA and MART-1 were expressed in 59%, 76% and 76% of the metastases, respectively. Simultaneously obtained specimens of peripheral blood, lymph nodes and metastatic tissues showed a high degree of homogeneity: 60%, 75% and 20% for tyrosinase, MIA and MART-1, respectively. Our findings suggest that the rather homogeneous expression pattern found in different tumour sites analysed in the same patient is of potential prognostic and therapeutic importance. Furthermore, melanoma lesions may be negative for the expression of antigens such as MART-1, and discrepancies in expression patterns between peripheral blood and metastatic tissues may occur, especially for this marker. Finally, our findings support the notion that molecular screening using an RT-PCR approach is appropriate in this kind of investigation.

Adult↗
PubMed2004

A new UV-B absorbing mycosporine with photo protective activity from the lichenized ascomycete Collema cristatum.

A novel photo protective mycosporine was isolated from the lichenized ascomycete Collema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially prevented pyrimidine dimer formation and completely prevented UV-B induced erythema when applied to the skin prior to irradiation.

Ascomycota↗
PubMed2004

Gene expression profiling of in vivo UVB-irradiated human epidermis.

BACKGROUND: Several recent studies have employed microarray profiling to study UVB-regulated gene expression in human skin. These studies are all based on UV-irradiated cultured cells that differ substantially from the intact tissues they are supposed to imitate. The purpose of the present study was to analyze the differential expression of UVB-regulated genes in intact human epidermis following in vivo UV irradiation. METHODS: The forearms of human volunteers were exposed to 4 MED of UVB in vivo, followed by removal of epidermal samples from exposed and non-exposed areas after 24 h. RNA samples were analyzed using oligonucleotide microarray (Affymetrix) technology analyzing 12 500 genes simultaneously. Verification of selected genes was performed by semi-quantitative reverse transcriptase polymerase chain reaction. RESULTS: Gene expression patterns clearly distinguished UV-exposed epidermis from unexposed skin. Classification of these genes into functional categories revealed that several biological processes are globally affected by UVB. Significant changes were seen in more than 800 genes. CONCLUSION: Human intact epidermis responds to a single low dose of in vivo UVB irradiation by differential regulation of numerous genes. Our results illustrate the power of global gene expression analysis of human epidermis to identify molecular pathways involved in UV-induced photodamage.

Adolescent↗
PubMed2003

Achievements of dermatological research in Denmark and Israel: a comparative 10-year study.

Wide differences of achievement in dermatological research between Denmark and Israel have been reported, although the two countries are comparable in terms of academic dermatological structure. The aims of the present study were to document these differences by means of bibliometric analysis, and to attempt to elucidate the causes of these differences. Employing MEDLINE searches for the 10-year period 1988-97, quantitative and qualitative comparisons of the dermatological publications from these two countries were conducted. We found the achievements of Danish dermatological research to be superior to those of Israel, and suggest that the large proportion of case reports and reviews is one cause of the relatively low ranking of Israeli dermatological research efforts.

Bibliometrics↗
PubMed2003

Diagnostic performance and retention of acquired skills after dermatology elective.

BACKGROUND: The dermatology elective often constitutes the future physician's only exposure to dermatologic practice. Cost-benefit considerations dictate that the elective enables the students to acquire useful diagnostic expertise in the short time period available, and that this expertise is not rapidly forgotten after completion of the elective. METHODS: In order to determine the efficacy of a 2-week dermatology elective in promoting diagnostic skills and to ascertain the preservation of the acquired expertise, kodachrome slide-based multiple-choice examinations were administered to 84 sixth year medical students at the beginning (pre-test) and completion (post-test) of the elective. The long-term retention of diagnostic skills was evaluated by re-testing 4-9 months after completion of the elective (follow-up test). RESULTS: The mean scores of correct answers at the pre- and post-test were 39.73% and 72.46%, respectively. The mean score at the follow-up test for students with a previous dermatology elective was 80.22%, compared with a score of 46.00% for students who did not participate in the elective. CONCLUSIONS: The 2-week dermatology elective significantly improved the diagnostic skills of the participants, and the knowledge obtained during the elective was retained for at least 4-9 months.

Clinical Clerkship↗
PubMed2003

Onchocerciasis among Ethiopian immigrants in Israel.

BACKGROUND: Onchocerciasis results from infestation by the nematode Onchocerca volvulus, and is characterized clinically by troublesome itching, skin lesions and eye manifestations. Since 1992, approximately 9,000 immigrants have arrived in Israel from the Kuwara province of northwest Ethiopia where the prevalence of onchocerciasis is particularly high. OBJECTIVES: To determine whether onchocerciasis is the cause of cutaneous and ocular symptoms among recent immigrants from the Kuwara province in Ethiopia. METHODS: We examined 1,200 recent immigrants from the Kuwara province residing at the Mevasseret Zion immigration center outside Jerusalem. Among them, patients with cutaneous signs suggestive of onchocerciasis underwent a skin-snip biopsy and a thorough eye examination. RESULTS: In the detailed skin examination performed in 83 patients, the most common skin finding was chronic papular onchodermatitis, found in more than 46 patients (55%); depigmentation and atrophy was found in 13 (15%) and 12 (14%), respectively. In 40 patients (48%), living microfilaria were detected in their skin snips. Of the 65 patients who underwent a through eye examination, 45 patients (66%) had ocular complaints. Corneal abnormalities were found in 55 of the 130 eyes (42%), active anterior segment intraocular inflammation and live microfilariae were found in 4 eyes (3%) and lens changes in 16 eyes (1%). Eleven eyes (9%) showed retinal or choroidal changes. CONCLUSIONS: Skin and eye manifestations associated with onchocerciasis are prevalent among symptomatic Ethiopians who immigrated to Israel from the Kuwara province.

Adolescent↗
PubMedDate not supplied

Onchocerciasis--river blindness.

Onchocerciasis results from infestation by the nematode Onchocerca volvulus and is characterized by troublesome itching, skin lesions, and eye manifestations. Although partially controlled by international mass prevention programs, onchocerciasis remains a major health hazard and is endemic in Africa, Arabia, and the Americas. Onchocerciasis is spread by bites from infested black flies, which transmit larvae that subsequently develop into adult filariae. Skin symptoms are commonly nonspecific and include severe pruritus, acute and chronic dermatitis, vitiligo-like hypopigmentation, and atrophy. Onchocercal ocular disease covers a large spectrum of manifestations, which in severe cases, may lead to blindness. Diagnosis is usually made by direct visualization of the larvae emerging from superficial skin biopsies, "skin snips." In some cases, the microfilariae can also be directly observed at the slit lamp when migrating into the anterior chamber of the eye. Ivermectin is, at present, the drug of choice for skin and ocular manifestations. Recent research using a chemotherapeutic approach that targets filarial Wolbachia symbionts in the treatment and control of onchocerciasis, however, suggests that 100 mg/d of doxycycline for 6 weeks might be effective in reducing the filarial load and preventing ocular symptoms.

Humans↗