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Biomedical subjects

S Emmert

Publications and source records attributed to S Emmert.

At least 19 recordsLinked to original sources
PubMed2006

[Dronabinol for supportive therapy in patients with malignant melanoma and liver metastases].

BACKGROUND: Loss of appetite and nausea can reduce the quality of life of patients with malignant melanoma and liver metastases. Often established antiemetic drugs fail to bring relief. Tetrahydrocannabinol (THC, Marinol), which is the active agent of Indian hemp, has been used successfully in this situation for other malignant tumors. PATIENTS AND METHODS: We treated 7 patients with hematogenous metastatic melanoma and liver metastases suffering from extensive loss of appetite and nausea supportively with dronabinol (Marinol. All of these patients had previously received standard antiemetic therapy without adequate relief. Dronabinol is a synthetic Delta-tetrahydrocannabinol. The drug was administered in capsule form. We evaluated the palliative effects of dronabinol with a special patient evaluation form, which was filled out at the beginning of the therapy and again after 4 weeks. RESULTS: The majority of patients described a significant increase in appetite and decrease in nausea. These effects remained for some weeks, but then decreased as metastases progressed and the general condition worsened. All of the patients experienced slight to moderate dizziness, but it was not sufficiently troubling to cause interruption or termination of therapy. CONCLUSION: Loss of appetite and nausea due to liver metastases of malignant melanoma can be treated in individual cases supportively with Dronabinol.

Adult↗
PubMed2004

Ultraviolet light selection assay to optimize oligonucleotide correction of mutations in endogenous xeroderma pigmentosum genes.

Various oligonucleotide (ODN)-based approaches have been proposed for their ability to correct mutated genes at the normal chromosomal locations. However, the reported gene correction frequencies of these approaches have varied markedly in different experimental settings, including when different tissues or cell types are targeted. In order to find the optimal ODN-based approach for a specific target tissue, an assay system that allows direct comparison of the different methods on that tissue is necessary. Herein, we describe an XP-UVC selection assay that can be used to evaluate and compare gene correction frequencies in different cell types obtained from a xeroderma pigmentosum (XP) patient, following treatment by different ODN-based approaches. As an experimental example, the XP-UVC selection assay was used to assess the ability of chimeric RNA/DNA ODN to correct point mutations in the XPA gene. This assay can be used to assess and evaluate other types of ODN-based approaches, and to further optimize them.

Base Sequence↗
PubMed2004

Results of a surveillance programme for patients at high risk of malignant melanoma using digital and conventional dermoscopy.

Patients with a high number of atypical naevi and a personal and/or family history of melanoma are at high risk of malignant melanoma. The objective of this study was to design a special documentation and surveillance programme using epiluminescence microscopy (ELM) and digital epiluminescence microscopy (DELM) to improve the surveillance of these patients. High-risk patients (n=212) were categorized by the number and phenotype of their naevi and their personal and family history of melanoma. Then patients were screened by the unaided eye, conventional photography, ELM and, in selected cases of atypia, DELM. Median follow-up was 18 months, and 2939 pigmented lesions were followed by DELM. Examination on the first visit identified 17 cutaneous melanomas. During the following observation period, another 17 melanomas were identified. Fifteen of these follow-up melanomas were exclusively identified based upon DELM. In these cases, subtle lesional changes occurred over time, and ELM diagnostic algorithms for differentiating benign melanocytic lesions from melanoma did not score a suspicion of melanoma. All melanomas, either pre-existing or developing during follow-up, were identified in an early, curable phase of tumour growth. We conclude that DELM follow-up for patients at high risk allows the early detection of melanomas that have not yet acquired melanoma-typical ELM features.

Adult↗
PubMed2004

Extracorporeal photochemotherapy for the treatment of exanthematic pityriasis rubra pilaris.

Pityriasis rubra pilaris (PRP) is a rare papulosquamous skin disease of unknown aetiology that has been categorized into five clinical types based on age at onset, cutaneous features and prognosis. We present a patient with chronic exanthematic type II atypical adult PRP, whose skin status was significantly improved with monthly extracorporeal photochemotherapy (ECP). Various therapeutic regimens including narrow-band UV-B, bath PUVA therapy, systemic fumaric acid esters and systemic cyclosporin had failed. Oral retinoids could not be administered due to a type IIa hyperlipoproteinemia with profound hepatic steatosis and elevated liver transaminases. The observed clinical benefit may encourage future clinical studies analysing the effectiveness of ECP in otherwise unresponsive cases of type II PRP.

Adult↗
PubMed2003

[Improved scar formation after using a medical surgical zipper for wound closure under tension].

BACKGROUND AND OBJECTIVE: The objective of the study was to evaluate the use of a medical surgical zipper (Medizip) for wound closure under tension in comparison to conventional cutaneous sutures. The surgical zipper is supposed to reduce wound tension by approximating of the wound edges via epidermal traction. PATIENTS/METHODS: This prospective study included patients with a wound diameter of more than 1 cm. 45 patients were treated with the surgical zipper, 38 were randomized into a control group with conventional wound closure. Scars were assessed after 6-18 months focusing on aesthetic and functional aspects. RESULTS: The average length of the scars in both groups was 9 cm, but after a observation time of at least 6 month, there were differences in the width of the scars. The group with the surgical zipper showed significantly thinner scars (2.74 mm versus 4.24 mm, p=0.0008). Only 17% of the Medizip patients developed unaesthetic rope ladder-like scars versus 65% in the control group. This observation was statistically significant (p<0.0001). CONCLUSIONS: Wound stabilization by approximation of the wound edges via surgical zipper results in improved scar formation in wounds with moderate tension. Using the Medizip trade mark in wounds under heavy tension is not recommended because of the possible development of to tension bullae under the zipper.

Adolescent↗
PubMed2003

Inefficacy of vindesine monotherapy in advanced stage IV malignant melanoma patients previously treated with other chemotherapeutic agents.

The anti-melanoma activity of vindesine as a single or polychemotherapeutic agent has been reported previously in adjuvant and first-line melanoma treatment. In this study, we investigated the usefulness of vindesine monotherapy as salvage therapy in stage IV melanoma patients after failure of other chemotherapies. Thirteen patients with progressive disease were treated with 3 mg/m2 vindesine every 2 weeks (median age, 61 years). Previous systemic treatment consisted of polychemotherapy or combined chemo-immunotherapy. All 13 patients suffered from visceral metastases (three lung, one liver, one adrenal gland and eight multiple visceral metastases). A median of three vindesine treatments was administered. Despite the various pre-treatments, the toxicity of vindesine was mild. In all 13 patients, vindesine treatment was stopped due to disease progression. The median survival after primary tumour diagnosis was 42 months (8-151 months), the survival after entering stage IV was 11 months (3-35 months), and the survival after starting vindesine therapy was 4 months (1-22 months). We conclude that vindesine monotherapy is ineffective in stage IV melanoma patients previously treated with other chemotherapeutic agents.

Adult↗
PubMed2002

[Long-term results of adjuvant chemotherapy after therapeutic lymph node dissection in patients with cutaneous malignant melanoma].

BACKGROUND AND OBJECTIVE: 224 patients with malignant melanoma and palpable axillary or inguinal lymphadenopathy underwent therapeutic lymph node dissection at the Martin-Luther-University in Halle, Germany. between 1983 and 1994. 120 received adjuvant chemotherapy; we evaluated the effects of various regimens in this group. PATIENTS/METHODS: Surgical treatment alone was performed in 104 patients. This group's results were compared to those of 94 patients who additionally received an adjuvant polychemotherapy [dacarbazine (DTIC), vincristine, 5-fluorouracil and hydroxyurea] and 26 patients who received either DTIC monotherapy or DTIC plus interferon-alfa. RESULTS: The median follow-up was 88 months. The 5-year survival rates were 31.0+/-5% after surgery alone, 26.4+/-4% after adjuvant polychemotherapy and 27.0+/-9% after DTIC based chemotherapy. The three survival curves did not differ significantly. In a multifactorial analysis, the number of metastatic lymph nodes was the single significant predictor of survival after therapeutic lymph node dissection, whereas Breslow thickness, ulceration, site of the primary melanoma, age, sex and adjuvant therapy were not significant. CONCLUSION: No beneficial effect of adjuvant chemotherapies could be demonstrated.

Adult↗
PubMed2001

The human XPG gene: gene architecture, alternative splicing and single nucleotide polymorphisms.

Defects in the XPG DNA repair endonuclease gene can result in the cancer-prone disorders xeroderma pigmentosum (XP) or the XP-Cockayne syndrome complex. While the XPG cDNA sequence was known, determination of the genomic sequence was required to understand its different functions. In cells from normal donors, we found that the genomic sequence of the human XPG gene spans 30 kb, contains 15 exons that range from 61 to 1074 bp and 14 introns that range from 250 to 5763 bp. Analysis of the splice donor and acceptor sites using an information theory-based approach revealed three splice sites with low information content, which are components of the minor (U12) spliceosome. We identified six alternatively spliced XPG mRNA isoforms in cells from normal donors and from XPG patients: partial deletion of exon 8, partial retention of intron 8, two with alternative exons (in introns 1 and 6) and two that retained complete introns (introns 3 and 9). The amount of alternatively spliced XPG mRNA isoforms varied in different tissues. Most alternative splice donor and acceptor sites had a relatively high information content, but one has the U12 spliceosome sequence. A single nucleotide polymorphism has allele frequencies of 0.74 for 3507G and 0.26 for 3507C in 91 donors. The human XPG gene contains multiple splice sites with low information content in association with multiple alternatively spliced isoforms of XPG mRNA.

Alternative Splicing↗
PubMed2001

Antiproliferative activity of ecteinascidin 743 is dependent upon transcription-coupled nucleotide-excision repair.

While investigating the novel anticancer drug ecteinascidin 743 (Et743), a natural marine product isolated from the Caribbean sea squirt, we discovered a new cell-killing mechanism mediated by DNA nucleotide excision repair (NER). A cancer cell line selected for resistance to Et743 had chromosome alterations in a region that included the gene implicated in the hereditary disease xeroderma pigmentosum (XPG, also known as Ercc5). Complementation with wild-type XPG restored the drug sensitivity. Xeroderma pigmentosum cells deficient in the NER genes XPG, XPA, XPD or XPF were resistant to Et743, and sensitivity was restored by complementation with wild-type genes. Moreover, studies of cells deficient in XPC or in the genes implicated in Cockayne syndrome (CSA and CSB) indicated that the drug sensitivity is specifically dependent on the transcription-coupled pathway of NER. We found that Et743 interacts with the transcription-coupled NER machinery to induce lethal DNA strand breaks.

Animals↗
PubMed2001

A stop codon in xeroderma pigmentosum group C families in Turkey and Italy: molecular genetic evidence for a common ancestor.

Xeroderma pigmentosum family G from Van, Turkey had two severely affected children: a son with multiple skin cancers who died at age 10 (XP67TMA), and an 8 y old daughter who began developing skin cancer before 3 y of age (XP68TMA). XP67TMA and XP68TMA cells were hypersensitive to killing by ultraviolet and the post-ultraviolet DNA repair level was 12-16% of normal. Host cell reactivation of an ultraviolet-treated reporter plasmid cotransfected with a vector expressing wild-type XPC cDNA assigned XP67TMA to xeroderma pigmentosum complementation group C. The XPC mRNA level was markedly reduced. Sequencing of the 3.5 kb XPC cDNA from XP67TMA showed a C-T mutation in XPC exon 8 at base pair 1840. This mutation converts the CGA codon of arginine at amino acid 579 to a UGA stop codon resulting in marked truncation of the 940 amino acid xeroderma pigmentosum C protein. Restriction fragment length polymorphism analysis of XPC exon 8 DNA in XP67TMA and XP68TMA showed that both affected children had a homozygous mutation and that both parents had heterozygous normal and mutated sequences at the same position consistent with a history of consanguinity in the family. The mutated allele also contained two XPC single nucleotide polymorphisms. The same mutated XPC allele was reported in an Italian family. Studies of 19 microsatellite markers flanking the XPC gene on chromosome 3 suggest that the XPC allele passed between Italy and Turkey approximately 300-500 y ago. This XPC allele containing a nonsense mutation is associated with severe clinical disease with multiple skin cancers and early death.

Adult↗
PubMed2000

The xeroderma pigmentosum group C gene leads to selective repair of cyclobutane pyrimidine dimers rather than 6-4 photoproducts.

We investigated the contribution of the xeroderma pigmentosum group C (XPC) gene to DNA repair. We stably transfected XPC cells (XP4PA-SV-EB) with XPC cDNA and selected a partially corrected (XP4PA-SE1) and a fully corrected (XP4PA-SE2) clone. Cell survival after UVC (254 nm) exposure was low for XP4PA-SV-EB, intermediate for XP4PA-SE1, and normal for XP4PA-SE2 cells. XP4PA-SV-EB cells had undetectable XPC mRNA and protein levels. XP4PA-SE1 cells had 130% of normal mRNA but 25% of normal protein levels, whereas XP4PA-SE2 cells had an 18-fold mRNA overexpression and normal XPC protein levels compared with normal cells. We measured cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PP) by using specific mAbs and the ELISA technique. XP4PA-SV-EB cells had no detectable removal of CPD or 6-4PP from their global genome by 24 h after 30 J/m(2) UVC exposure. The partially corrected XP4PA-SE1 cells had normal repair of CPD but minimal repair of 6-4PP by 24 h, whereas the fully corrected XP4PA-SE2 cells regained normal CPD and 6-4PP repair capacities. We also exposed pRSVcat plasmid to UVC (to induce CPD and 6-4PP), to UVC + photolyase (to leave only 6-4PP on the plasmid), or to UVB + acetophenone (to induce only CPD). Host cell reactivation of UVB + acetophenone-, but not of UVC + photolyase-treated plasmids was normal in XP4PA-SE1 cells. Thus, increasing XPC gene expression leads to selective repair of CPD in the global genome. Undetectable XPC protein is associated with no repair of CPD or 6-4PP, detectable but subnormal XPC protein levels reconstitute CPD but not 6-4PP repair, and normal XPC protein levels fully reconstitute both CPD and 6-4PP repair.

Animals↗
PubMed2000

[Congenital manifestations of juvenile xanthogranuloma (large nodular form)].

An infant girl presented at birth with multiple, large nodular xanthogranulomas. Her monozygotic twin sister was not affected. The congenital tumors were up to 1.5 cm in diameter, done-shaped and mainly located on the head and the upper half of the body. Histologically the cells were characterized as CD68+ non-Langerhans histiocytes. Follow-up for 18 months showed no new tumors and regression of the existing ones. No extra-cutaneous manifestations were observed. Knowledge of the differential diagnosis, especially the group of Langerhans cell histiocytosis, is essential for prognosis estimation.

Biopsy↗
PubMed2000

Clinical, cellular, and molecular features of an Israeli xeroderma pigmentosum family with a frameshift mutation in the XPC gene: sun protection prolongs life.

An Ashkenazi Jewish Israeli family with two children affected with severe xeroderma pigmentosum was investigated. A son, XP12TA, developed skin cancer at 2 y and died at 10 y. A daughter, XP25TA, now 24 y old, was sun protected and began developing skin cancers at 10 y. Their cultured skin fibroblasts showed reductions in post-ultraviolet survival (11% of normal), unscheduled DNA synthesis (10% of normal), global genome DNA repair (15% of normal), and plasmid host cell reactivation (5% of normal). Transcription-coupled DNA repair was normal, however. Northern blot analysis revealed greatly reduced xeroderma pigmentosum complementation group C mRNA. A plasmid host cell reactivation assay assigned the cells to xeroderma pigmentosum complementation group C. Cells from both parents and an unaffected child exhibited normal post-ultraviolet-C survival and normal DNA repair. Sequencing the xeroderma pigmentosum complementation group C cDNA of XP12TA and XP25TA revealed a homozygous deletion of two bases (del AT 669-670) in exon 5 with a new termination site 10 codons downstream that is expected to encode a truncated xeroderma pigmentosum complementation group C protein. Sequence analysis of the xeroderma pigmentosum complementation group C cDNA in cells from the parents found identical heterozygous mutations: one allele carries both the exon 5 frameshift and an exon 15 polymorphism and the other allele carries neither alteration. Cells from the unaffected brother had two normal xeroderma pigmentosum complementation group C alleles. This frameshift mutation in the xeroderma pigmentosum complementation group C gene led to reduced DNA repair with multiple skin cancers and early death. Sun protection delayed the onset of skin cancer and prolonged life in a sibling with the same mutation.

Adult↗
PubMed2000

Alterations of DNA repair in melanoma cell lines resistant to cisplatin, fotemustine, or etoposide.

Resistance to chemotherapy is a common phenomenon in malignant melanoma. In order to assess the role of altered DNA repair in chemoresistant melanoma, we investigated different DNA repair pathways in one parental human melanoma line (MeWo) and in sublines of MeWo selected in vitro for drug resistance against four commonly used drugs (cisplatin, fotemustine, etoposide, and vindesine). Host cell reactivation assays with the plasmid pRSVcat were used to assess processing of different DNA lesions. With ultraviolet-irradiated plasmids, no significant differences were found, indicating a normal (nucleotide excision) repair of DNA photoproducts. With singlet oxygen-treated plasmid, the fotemustine- and cisplatin-resistant lines exhibited a significantly increased (base excision) repair of oxidative DNA damage. With fotemustine-treated plasmid, the fotemustine-resistant subline did not exhibit an increased repair of directly fotemustine-induced DNA damage. Similar results were obtained with cisplatin-induced DNA crosslinks in the cisplatin-resistant line. The fotemustine- and etoposide-resistant sublines have been shown to exhibit a reduced expression of genes involved in DNA mismatch repair. We used a "host cell microsatellite stability assay" with the plasmid pZCA29 and found a 2.0-fold to 2.5-fold increase of microsatellite frameshift mutations (p < or = 0.002) in the two resistant sublines. This indicates microsatellite instability, the hallmark of an impaired DNA mismatch repair. The increased repair of oxidative DNA damage might mediate an increased chemoresistance through an improved repair of drug-induced DNA damage. In contrast, a reduced DNA mismatch repair might confer resistance by preventing futile degradation of newly synthesized DNA opposite alkylation damage, or by an inability to detect such damage and subsequent inability to undergo DNA-damage-induced apoptosis.

Antineoplastic Agents↗
PubMed2000

A new xeroderma pigmentosum group C poly(AT) insertion/deletion polymorphism.

We found a common biallelic polymorphism (PAT) in the xeroderma pigmentosum complementation group C (XPC) DNA repair gene consisting of an insertion of 83 bases of A and T [poly(AT)] and a 5 base deletion within intron 9. We developed a PCR assay to resolve the XPC PAT+ and PAT- alleles and found that the PAT+ allele frequency was 0.44 in 156 cancer-free donors from the Johns Hopkins School of Public Health, 0.41 in 263 cancer-free donors from the Baltimore Longitudinal Study of Aging and 0.36 in samples from 216 unselected donors from NIH. We also found a single nucleotide polymorphism in exon 15 of the XPC gene (A2920C, Lys939-->Gln) that creates a new enzyme restriction site. This XPC exon 15 single nucleotide polymorphism occurred at a frequency of 0.38 in 98 NIH donors and is in linkage disequilibrium with the PAT locus. We developed an allele-specific complementation assay utilizing post-UV host cell reactivation to assess DNA repair capacity of polymorphic alleles. We found similar DNA repair with XPC 2920A and XPC 2920C. These common polymorphisms in the XPC DNA repair gene may be useful for molecular epidemiological studies of cancer susceptibility.

Adolescent↗
PubMed1998

[Erythrokeratodermia progressiva symmetrica Darier-Gottron with generalized expression].

A mother and her son presented with erythrokeratodermia progressiva symmetrica Darier-Gottron. Both patients developed symmetrical erythematous and hyperkeratotic plaques on the extremities and face at the age of 6 months. At the age of 2 1/2 years the son suffered from rapid progression of the disease to involve the entire skin. The disease of his mother had shown a similar course, however, with spontaneous regression at the age of 10 years. The clinical features of this generalized condition were identical to congenital lamellar ichthyosis. Light microscopy was non-specific with orthohyperkeratosis, focal parakeratosis and acanthosis. Electron microscopy revealed numerous keratinosomes in the stratum granulosum, keratinosome-derived lamellae in the intercellular space and partly augmented keratohyalin with clumping. In the stratum spinosum short tonofilament bundles with clumping were remarkable. The child experienced a significant and persistent improvement with systemic retinoids. His mother's disease was successfully controlled with intermittent retinoid therapy. With the clinical and ultrastructural criteria presently available, an unambiguous differentiation between erythrokeratodermia progressiva symmetrica, usually a localized disorder of keratinization, however with intermittent generalization, and other disorders of keratinization seems difficult.

Adult↗
PubMed1998

Xeroderma pigmentosum group C splice mutation associated with autism and hypoglycinemia.

A 4 y old boy of Korean ancestry had xeroderma pigmentosum (XP) with sun sensitivity, multiple cutaneous neoplasms, and inability to speak. Neurologic examination revealed hyperactivity and autistic features without typical XP neurologic abnormalities. Cultured skin fibroblasts (XP22BE) showed decreased post-UV survival, reduced post-UV plasmid host cell reactivation and defective DNA repair (16% of normal unscheduled DNA synthesis in intact cells and undetectable excision repair in a cell free extract). In vitro and in vivo complementation assigned XP22BE to XP group C (XPC) and a markedly reduced level of XPC mRNA was found. Two XPC cDNA bands were identified. One band had a deletion of 161 bases comprising the entire exon 9, which resulted in premature termination of the mutant XPC mRNA. The larger band also had the same deletion of exon 9 but, in addition, had an insertion of 155 bases in its place (exon 9a), resulting in an in-frame XPC mRNA. Genomic DNA analysis revealed a T-->G mutation at the splice donor site of XPC exon 9, which markedly reduced its information content. The 155 base pair XPC exon 9a insertion was located in intron 9 and was flanked by strong splice donor and acceptor sequences. Analysis of the patient's blood showed persistently low levels of glycine (68 microM; NL, 125-318 microM). Normal glycine levels were maintained with oral glycine supplements and his hyperactivity diminished. These data provide evidence of an association of an XPC splice site mutation with autistic neurologic features and hypoglycinemia.

Alternative Splicing↗