Biomedical subjects
Publications and source records attributed to W Stolz.
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Natural minerals, such as widespread quartz and feldspars, have physical properties which enable them to be used as radiation dosimeters. The underlying luminescence phenomena have made it possible in recent decades to determine the age of a variety of materials important for quaternary geochronometry and archaeochronometry. We present a new luminescence dating method based on radioluminescence measurements of potassium feldspar. For the first time we have been able to investigate the light-emitting transition of electrons from the conduction band to an optically sensitive electron trap. Many advantages can be derived from such direct measurements of the metastable electron density in this particular trap, which produces the age-dependent signal. The method can be used to date the last light exposure of feldspar grains within a range of a few hundred to more than 200,000 years. Examples are presented of age determination of various waterlaid quaternary sands. The results of a basic study of feldspar radioluminescence also shed light on effects not sufficiently understood in conventional dating by luminescence techniques, especially in infrared optically stimulated luminescence dating of feldspar. http://link.springer. de/link/service/journals/00114/bibs/9086009/90860441.htm</HEA
Variations in the length of simple repetitive tandem repeats (microsatellite instability, MIN) between constitutive and tumour DNA, which is characteristic of tumours in patients affected with hereditary nonpolyposis colon cancer (HNPCC), have been found to be very important in the carcinogenesis of a variety of human neoplasms. Recently, MIN has been found in sebaceous and colorectal tumours as well as in keratoacanthomas of Muir-Torre syndrome. In order to elucidate the significance of both MIN and loss of heterozygosity (LOH) in the pathogenesis of sporadic keratoacanthomas, the presence of MIN and LOH at five loci [chromosome 5q21 (D5S346, APC), 9p21 (D9S171, p16), 10pter (D10S89, Mfd28), 11p (D11S904) and 17p12 (D17S520, p53)] was evaluated. MIN was found at only one locus (p53) in 1 of 12 keratoacanthomas and no evidence for the presence of LOH could be detected. Our results suggest that, in contrast to keratoacanthomas associated with Muir-Torre syndrome, neither MIN nor LOH appear to be significant in the induction of sporadic keratoacanthomas.
We describe a 65-year-old woman who had had wart-like lesions on the hands, lower arms and forehead for about 45 years. She had already had several basal cell carcinomas excised. Histological study, electron microscopy and in situ hybridization [human papilloma virus (HPV)-types 5/8/12/14/19-23/25/36] of skin biopsies confirmed a diagnosis of epidermodysplasia verruciformis (EV). Photodynamic therapy (PDT) was performed using a 20% 5-aminolaevulinic acid ointment applied for 6 h to the lesions and irradiating using an incoherent light source (lambda = 580-740 nm, 160 mW/cm2, 160 J/cm2). Following PDT, blistering and crusting of the lesions occurred, but these healed completely within 2-3 weeks without scarring, and the cosmetic result was excellent. Six months after PDT a skin biopsy was taken. In situ hybridization was positive for HPV type 8 in skin which was clinically and histologically normal. Twelve months after PDT a few lesions had recurred on the hands. Although permanent cure of EV cannot be achieved by any therapy at present and single lesions continue to appear in this patient, topical PDT might result in better control of HPV-induced lesions.
The detection of tumor-specific mRNA transcripts in the blood of patients by reverse transcription (RT)-PCR has been used as a very sensitive technique for determining systemically disseminated tumor cells. On the basis of previous expression studies, we aimed to trace melanoma cells in the blood of melanoma patients by RT-PCR of melanoma-inhibitory activity (MIA) mRNA. To detect sensitively MIA transcripts in total RNA isolated from peripheral blood mononuclear cells (PBMCs), we established a sensitive PCR-ELISA system. With this assay, we detected one melanoma cell in 2 ml of blood by a single round of 32 PCR cycles. A total of 295 PBMC samples isolated from 166 patients with melanocytic tumors were tested with the MIA RT-PCR-ELISA: (a) 58 patients (99 samples) with malignant melanomas in stage I; (b) 49 patients (65 samples) with malignant melanomas in stage II; and (c) 47 patients (116 samples) with metastasized melanomas (stages III and IV), with an additional 12 patients (15 samples) with benign melanocytic nevi. Forty-four (26.8%) of 164 samples isolated from patients with melanomas in stages I and II were positive for MIA mRNA; in stages III/IV, 33 (28.4%) of 116 samples of patients, irrespective of clinically evident disease, were positive. Eleven (84.6%) of 13 PBMC samples from patients with metastasized melanoma and clinically evident disease without treatment were MIA mRNA-positive in contrast to only 19 (25.7%) of 74 samples isolated from patients in stage IV with metastasis during chemotherapy. Furthermore, none of the 16 PBMC samples of patients in stage IV without clinically detectable metastases at that time point during chemotherapy was MIA mRNA-positive. Interestingly, of the 44 positive samples (26.8%) isolated from patients with melanomas in stages I and II, 20 were still positive when retested after complete excision of the tumor. Our results reveal that amplification of MIA mRNA from the PBMCs of patients with malignant melanomas by PCR-ELISA provides a useful means to detect tumor cells in the systemic blood circulation. A correlation between positive blood samples and tumor burden in stages III and IV was detected, and, in addition, a significant effect of chemotherapy with respect to the reduction of the number of systemically spread tumor cells was observed. However, MIA amplification seems to be of little value as a surrogate marker for clinical staging or the detection of metastatic disease.
Using RNA arbitrarily primed PCR, the authors selected for transcripts with cell cycle-related differential expression in cultured human melanocytes. Among the partial cDNAs cloned, a novel cDNA was identified, which showed 54% identity to the recently cloned cDNA of the retinoblastoma binding protein-2 (RBP2). The 6.5-kB full-length cDNA of this RBP2-related gene, termed RBP2 homolog 1 (RBP2-H1), was obtained from a human teratocarcinoma cDNA library. Two independent libraries from human malignant melanomas were negative. A computerized sequence analysis revealed highly conserved motifs with possible functional meaning: two domains that, in the RBP2 homolog, mediate the binding and interaction with the proteins encoded by the retinoblastoma susceptibility gene, the TATA-binding protein, and the oncoprotein rhombotin 2; in addition, two DNA-binding zinc finger/leukemia-associated protein motifs were detected. Because a functional role in cell-cycle control and transcriptional activation can be envisioned, we investigated the expression of this novel transcript in normal fetal and adult tissues, as well as tissues of benign and malignant melanocytic tumors. By conducting multiple Northern blot, RT-PCR, and in situ hybridization analyses, the authors showed that the corresponding mRNA is expressed in virtually all normal tissues. Accordingly, they found RBP2-H1 expression in microdissected tissue samples from benign melanocytic nevi (n = 10). In contrast, the transcript is significantly down-regulated or even lost in tissue samples from human malignant melanomas (n = 13), melanoma metastases (n = 10), and melanoma cell lines (n = 7). The authors concluded that the loss or down-regulation of RBP2-H1 expression could be a useful molecular marker for a transformed phenotype in the human melanocytic system.
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Diagnosing dermatologic skin conditions can be difficult, especially in pigmented skin lesions. Therefore, the consultation of an expert via teledermatology could prove vital. For this purpose, a rapid transfer of medical data including high resolution images is essential. This transfer can be performed with a variety of modern telecommunication technologies, including ISDN, highspeed-ISDN, Internet, and Intranet. As the levels of both communication software and camera-systems can be quite different, our survey investigated the equipment of 84 dermatologists in private practice. A questionnaire was distributed on computer equipment, operating system software, and any image documentation systems used, as well as required telecommunications equipment and possible applications of tele-dermatology. This survey showed a response rate of 54% and proves that dermatologists in private practice are interested in telemedicine services. Most dermatologists surveyed use Windows 95 operating software and 74% have access to modern ISDN modems or PC-cards. Dermatologists currently prefer applications with low-tech communication hardware and software requirements. Consultation of dermatological centers was the favored application with 59%. Our survey clearly demonstrates that a high percentage of dermatologists in private practice would use tele-dermatology. In our experience, for the excellence of this service an image documentation system is essential to provide the tele-dermatological expert with standardized images with constant illumination.
HISTORY AND CLINICAL FINDINGS: For some months a 57-year-old woman had noted increasing shortness of breath, associated in the last few weeks with undirected vertigo and several brief periods of lost consciousness. She was finally admitted because of additional central facial paresis. On auscultation a high-frequency systolic murmur was heard over the apex and a discrete diastolic murmur over Erb's point. There were numerous facial freckles and three cutaneous myxomas. INVESTIGATIONS: Echocardiography revealed irregular tumours throughout the left atrium and a large broad-based one prolapsing through the mitrale valve in diastole. Computed tomography demonstrated a 6 x 6 cm tumour in the left lower abdomen, probably arising from the left ovary, and a second 3 x 3 cm presacral tumour. TREATMENT AND COURSE: At cardiac surgery four tumours were found in the left atrium and resected: histologically they were benign myxomas. Removal required extensive resection in the area of the interatrial septum and the atrial wall, resulting in 2 degrees AV block for which a VDD pacemaker was implanted. CONCLUSION: Atrial myxomas may be the cardinal sign of the Carney Complex, an autosomal dominant syndrome with cutaneous myxomas, myxoid abdominal tumours, hormone-producing tumours in the testicles, adrenal cortex or hypophysis, schwannoma as well as lentigines. For this reason, further tumours should be looked for if freckles and/or cutaneous tumours are found in association with an atrial myxoma. The patient and family should be informed about the genetic aspects.
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The gene of the cyclin-dependent kinase 4 (CDK4)-inhibitor p16INK4A (CDKN2/MTS1) has been proposed as a candidate for a tumor-suppressor gene located on chromosome 9p21, a frequently deleted region in a series of human cancers including malignant melanoma. An increasing and sometimes conflicting body of data has accumulated regarding the frequency of homozygous deletions and mutations as well as the importance of p16INK4A in malignant melanoma. The purpose of this review is therefore to summarize the current knowledge on p16INK4A and to discuss its biologic significance in the pathogenesis of melanocytic tumors.
Several reports more than ten years ago provided evidence that allopurinol may be effective for cutaneous sarcoidosis. We therefore treated two patients with histologically confirmed scar sarcoidosis and two with nodular sarcoidosis. A daily dosage of 300 mg allopurinol was given over a period of 4-7 months as single drug therapy. In both patients with scar sarcoidosis, the skin manifestations completely regressed while in the patients with nodular sarcoidosis there was significant improvement. The concomittant pulmonary involvement in two patients was unpredictable, in one patient improved while the other was deteriorated, The mode of action is still unclear but because of the positive results and the low rate of side effects, allopurinol seems a reasonable agent for treating cutaneous sarcoidosis.
A common adverse effect of minocycline therapy is cutaneous pigmentation. We describe two patients who presented with hyperpigmentation caused by minocycline. One patient, aged 54 years, had taken minocycline due to lung silicosis for 3 years before black pigmentation of the face occurred. The other 49 year-old patient developed grey-black hyperpigmentation on both lower legs after a 6-month therapy with minocycline for folliculitis. This patient was treated with the Q-switched ruby laser and the pigmentation resolved in the treated area. The different clinical and histological forms of minocycline-induced hyperpigmentation are discussed.
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This is the first case in the literature describing naevi spili, café-au-lait spots and melanocytic naevi aggregated along-side Blaschko's lines. The pattern of melanocytic lesions in our patient is different from the congenital pigmentary syndromes and the segmental distribution of melanocytic naevi, the quadrant distribution of dysplastic naevi or the partial unilateral lentiginosis which here are shortly reviewed. The distribution may be a result of a somatic mutation occurring at an early stage of embryogenesis when neural structures had already been formed.
Recently p73, a novel p53 homologous tumour suppressor gene, has been cloned and mapped to chromosome 1p36. Like p53, important functions of p73 in controlling the cell cycle and programmed cell death have been described. Loss of p73 has been demonstrated in neuroblastomas and its involvement in tumorigenesis has been suggested to occur in other neuroectodermal cancers. Since genetic alterations at the tumour suppressor locus 1p36 have been also identified in malignant melanomas, we investigated the expression of p73 in a panel of nine different human melanoma cell lines, 17 melanocytic naevi, 17 primary malignant melanomas and 20 metastases by reverse transcriptase polymerase chain reaction (PCR) and Southern blotting. We observed significant p73 mRNA expression in all the cell lines and tissue specimens except one benign melanocytic naevus and one melanoma metastasis. Sequencing the PCR fragments of nine melanoma cell lines derived from primary tumours and five metastases over the entire p73 DNA binding domain revealed wild-type sequences in all cases. In summary, we conclude that loss of p73 mRNA expression or mutations in the p73 DNA binding domain do not represent common genetic events involved in the pathogenesis of malignant melanomas.
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