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Biomedical subjects

S Sommer

Publications and source records attributed to S Sommer.

At least 55 records · Page 3Linked to original sources
PubMed2000

Active expression of the ubiA gene from E. coli in tobacco: influence of plant ER-specific signal peptides on the expression of a membrane-bound prenyltransferase in plant cells.

The ubiA gene from E. coli codes for 4-hydroxybenzoate: polyprenyldiphosphate 3-polyprenyltransferase, an integral membrane protein involved in ubiquinone biosynthesis. This prokaryotic membrane protein was stably expressed in tobacco using Agrobacterium tumefaciens-mediated transformation. Transgenic lines containing a direct fusion of the ubiA structural gene to a 35S-derived promoter gave very low enzyme activity levels (average 0.16 pkat/mg). Inclusion of an N-terminal ER-specific signal peptide from a lectin gene from Phaseolus vulgaris resulted in an average activity of 1.08 pkat/mg in the transgenic tobacco lines. The additional inclusion of a C-terminal HDEL tetrapeptide, responsible for the retention of proteins in the endoplasmic reticulum of eukaryotic cells, increased the activity to 18.6 pkat/mg. When the promotor of this construct was changed from the 35S derivative to the recently described very strong plant promoter (ocs)3mas, the activity increased further to 128.6 pkat/mg. The most active tobacco line showed activities of the introduced enzyme which exceeded those of wild-type E. coli (the source of ubiA) by a factor of 1100. These results demonstrate the efficacy of plant ER-specific signal peptides for the active expression of a prokaryotic membrane protein in plants.

Alkyl and Aryl Transferases↗
PubMed2000

Papuloerythroderma of Ofuji responding to treatment with cyclosporin.

We describe a patient with papuloerythroderma of Ofuji (PE) of unknown cause, in whom no underlying malignancy was found. Topical steroids and systemic antihistamines did not resolve the rash. Systemic steroids induced a remission of the PE, which was not maintained on reduction of the dose. Therefore, cyclosporin was added which did lead to rapid clearing of the skin. Remission was maintained after discontinuation of treatment.

Aged↗
PubMed2000

Specific amino acid changes enhance the anti-recombination activity of the UmuD'C complex.

In addition to being an essential component of trans-lesion synthesis, the UmuD'C complex is an antagonist of RecA-mediated homologous recombination. When constitutively expressed at an elevated concentration, the UmuD'C complex sensitizes recA+ bacteria to DNA damage, whereas it has no effect on bacteria expressing a RecA [UmuR] protein that overcomes recombination inhibition. Using as a genetic screen enhanced cell killing on mitomycin plates, we isolated novel umuD' and umuC mutations that restored mitomycin sensitivity to recA D112G [UmuR] bacteria overproducing the UmuD'C complex. The mutations were named [Rin++] because a characterization in a recA+ as well in a recA D112G background showed that they enhanced UmuD'C-promoted recombination inhibition in two assays, conjugational recombination and recombinational repair of palindrome-containing DNA. The [Rin++] mutations affect five amino acids, G25D, S28T, P29L, E35K, and T95R, in UmuD' and seven, F10L, Y270C, K277E, F287L, F287S, K342Q and F351I, in UmuC. These amino acids might play a key role in the UmuD'C anti-recombination activity. None of the [Rin++] mutations enhanced UmuD'C-promoted mutagenic bypass of UV lesions, in contrast, several lead to a defect in this process. In this study, we discuss a few molecular mechanisms that could account for the recombination and mutagenesis phenotypes of a mutant UmuD'C [Rin++] complex.

Amino Acids↗
PubMed2000

[The function of shame in depressive disorders].

Beginning with the view of the function feelings of shame for psychiatric disturbances the relationship between shame and affective disorders was described. In a sample of 113 inpatients with depressive symptoms and 81 healthy controls, the relationship between shame, trait-anxiety and intolerance of ambiguity was examined. The results showed that the clinical group scored higher on all measures than the control group. Furthermore, the potential impact of publicity was demonstrated in an experimental varied scenario. Individuals with high shame level expected a stronger intervention after a norm violation than individuals with low shame level. The results were discussed on the background of the function feelings of shame for affective disorders.

Adolescent↗
PubMed2000

Genetic engineering on shikonin biosynthesis: expression of the bacterial ubiA gene in Lithospermum erythrorhizon.

The naphthoquinone pigment shikonin from Lithospermum erythrorhizon Sieb. et Zucc. (Boraginaceae) was the first plant secondary metabolite produced in industrial scale from plant cell cultures. We have now manipulated the biosynthetic pathway leading to shikonin in L. erythrorhizon by introduction of the bacterial gene ubiA. This gene of Escherichia coli encodes 4-hydroxybenzoate-3-polyprenyltransferase, a membrane-bound enzyme that catalyzes a key step in ubiquinone biosynthesis. Using geranyl diphosphate (GPP) as substrate, it is able to catalyze the formation of 3-geranyl-4-hydroxybenzoate (GBA), a principal step of shikonin biosynthesis. The prokaryotic ubiA gene was fused to two signal sequences for targeting of the resulting peptide to the endoplasmic reticulum (ER). Constructs with different constitutive promoters were introduced into L. erythrorhizon using Agrobacterium rhizogenes-mediated transformation. In the resulting hairy root lines, high UbiA enzyme activities could be observed, reaching 133 pkat mg(-1). Expression of ubiA resulted in an accumulation of GBA in an amount exceeding that of the control culture by a factor of 50. However, the ubiA-transformed lines showed only a marginal (average 22%) increase of shikonin production in comparison to the control lines, and there was no significant correlation of UbiA enzyme activity and shikonin accumulation. This suggests that overexpression of ubiA alone is not sufficient to increase shikonin formation, and that further enzymes are involved in the regulation of this pathway.

Alkyl and Aryl Transferases↗
PubMed2000

The relationship between five-factor personality measurements and ICD-10 personality disorder dimensions: results from a sample of 229 subjects.

This article examines the relationship between the five-factor model (FFM) and dimensional ICD-10 personality disorders. In a follow-up study of a child and adolescent psychiatric cohort, former patients and controls were assessed with NEO-FFI and the IPDE interview (CD-10 personality disorder). Full data were available for 229 subjects (149 former patients, 80 controls). Multiple regression analysis showed that the five factors of the FFM as independent variables explained between 5% (schizoid personality disorder) and 32% (anxious personality disorder) of the variance of ICD-10 dimensional personality disorder scores. For the two types of emotionally unstable personality disorder dimension (impulsive and borderline), for anxious (avoidant) personality disorder dimension and for the total score of any personality disorder dimension, FFM explained between 17% and 32% of the variance with almost identical results for the former patient group and the control group. High neuroticism was a feature of paranoid, emotionally unstable, histrionic, anankastic, anxious (avoidant), and dependent personality disorder dimensions, whereas low agreeableness was found in dissocial, emotionally unstable and histrionic personality disorder dimensions. Low extraversion was found in schizoid, anxious (avoidant) and dependent personality disorder dimensions, whereas histrionic PD dimension correlated with high extraversion. We find that the FFM is valuable for the further understanding not only of DSM-IV but also of ICD-10 personality disorder dimensions. The differences between ICD-10 and DSM-IV in this respect seem to be small.

Adult↗
PubMed2000

[Central retinal vein occlusion in a patient treated with antiandrogenic drug].

Central retinal vein occlusion (CRVO) is usually seen in older adults and is often associated with systemic vascular disease, this is much less evident in young people. A case report of a 28-year-old woman presented a central retinal vein occlusion in her left eye. This young woman was treated with antiandrogenic drug. Investigations revealed an abnormality of the hemostatic system. The central retinal vein occlusion was resolved and the fundus assumed a normal appearance one-month after the primary episode. Retinal vascular occlusions with antiandrogenic drug may be due to three mechanisms: increased platelet cell aggregation, alteration of fibrinolytic system and vascular endothelium hyperplasia.

Adult↗
PubMed2000

Pulsed dye laser treatment of port-wine stains in pigmented skin.

BACKGROUND: Little information is available on pulsed dye laser treatment of darker Fitzpatrick skin types. METHODS: We retrospectively reviewed our clinical experience treating mainly facial (12/13) port-wine stains (PWSs) in 13 patients of skin type V, whose ages ranged from 3 to 65 years. RESULTS: The response was excellent in 2 patients, good or moderate in 4 each, slight in 1, and poor in 2. Hyperpigmentation occurred in 6 patients and hypopigmentation in 1, which improved despite continuing treatment. Limited atrophic scarring developed in two patients. Although these results were less good and side effects more frequent than described in skin types I to IV, 6 patients (46%) achieved a good or excellent response and 85 (87.6%) of the total 97 laser treatments were not associated with significant problems. CONCLUSION: Patients of skin type V with a PWS should not be excluded from pulsed dye laser therapy, provided that treatment expectations and risks are fully discussed.

Adolescent↗
PubMed2000

[Birdshot chorioretinopathy associated with tamoxifen retinal toxicity].

We report a case of Birdshot retinochoroidopathy associated with ocular toxicity due to tamoxifen. Adverse drug effects were suspected due to the presence of yellow-white dots in the paramacular region and the fovea and by modifications of the retinal epithelial pigments. Ocular toxicity should be suspected as it may be reversible if recognized and stopped early. Other adverse ocular effects are described and the pathogenic mechanism of tamoxifen retinopathy analyzed.

Antineoplastic Agents, Hormonal↗
PubMed1999

The relationship between pityriasis rubra pilaris and inflammatory arthritis: case report and response of the arthritis to anti-tumor necrosis factor immunotherapy.

Pityriasis rubra pilaris (PRP) refers to a group of erythematous, scaling dermatologic conditions that have been associated with seronegative arthritis. We report a case of polyarthritis in a young man with PRP in which magnetic resonance imaging suggested an entheseal-based pathology for the joint disease. The arthritis, but not the skin condition, demonstrated dramatic response to anti-tumor necrosis factor immunotherapy.

Adolescent↗
PubMed1999

Facial hirsutism treated with the normal-mode ruby laser: results of a 12-month follow-up study.

Fifty-one patients of skin type I to IV with facial hirsutism received treatment with the normal-mode ruby laser (950-micros pulse; 4-mm spot; mean fluence, 49 J/cm(2); maximum fluence, 66 J/cm(2)). For each patient, one site was treated once only, and a second site was treated 4 times at 4-week intervals. After 48 weeks, 46 patients were available for assessment. After a single treatment, hair counts were reduced to a mean of 45% at 4 weeks (pretreatment median of 63 hairs down to 26), increased to 80% (median, 51 hairs) at 12 weeks, were 65% (median, 41 hairs) at 24 weeks, and were 59% (median, 35 hairs) at 48 weeks. Four weeks after 3 treatments, the hair counts had reduced to a mean of 30% (pretreatment median of 68 hairs down to 15). Twelve weeks after 4 treatments, the hair counts had increased to 45% (median, 24 hairs) and were 39% after 36 weeks (median, 22.5 hairs). No anesthesia was needed. Treatment tolerance improved with consecutive visits, allowing higher fluences to be used. Hyperpigmentation developed in 9 patients, which had faded completely in 8 patients at the end of the study. One patient showed hypopigmentation. Depressions in the skin below the jaw line developed in 5 patients, which resolved completely within 4 to 32 weeks. We conclude that normal-mode ruby laser treatment is well tolerated and leads to significant improvement of facial hirsutism, which is maintained for at least 48 weeks. Repeated treatments result in greater clinical effects.

Adolescent↗
PubMed1999

Atrophie blanche-like scarring after pulsed dye laser treatment.

Pulsed dye laser treatment is well established for the treatment of port-wine stains and other vascular skin lesions. Although hyperpigmentation is quite common, other side effects such as hypopigmentation and atrophic scarring occur infrequently, and hypertrophic scarring is rare.

Adult↗
PubMed1999

Genetic engineering of shikonin biosynthesis hairy root cultures of Lithospermum erythrorhizon transformed with the bacterial ubiC gene.

The biosynthetic pathway to 4-hydroxybenzoate (4HB), a precursor of the naphthoquinone pigment shikonin, was modified in Lithospermum erythrorhizon hairy root cultures by introduction of the bacterial gene ubiC. This gene of Escherichia coli encodes chorismate pyruvate-lyase (CPL), an enzyme that converts chorismate into 4HB and is not normally present in plants. The ubiC gene was fused to the sequence for a chloroplast transit peptide and placed under control of a constitutive plant promoter. This construct was introduced into L. erythrorhizon by Agrobacterium rhizogenes-mediated transformation. The resulting hairy root cultures showed high CPL activity. 4HB produced by the CPL reaction was utilized for shikonin biosynthesis, as shown by in vivo inhibition of the native pathway to 4HB with 2-aminoindan-2-phosphonic acid (AIP), an inhibitor of phenylalanine ammonia-lyase. A feeding experiment with [1,7-13C2]shikimate showed that in the absence of AIP the artificially introduced CPL reaction contributed ca. 20% of the overall 4HB biosynthesis in the transgenic cultures. ubiC transformation did not lead to a statistically significant increase of shikonin formation, but to a 5-fold increase of the accumulation of menisdaurin, a nitrile glucoside which is presumably related to aromatic amino acid metabolism.

Cell Line, Transformed↗
PubMed1999

Microbiological and molecular diagnosis of deep localized cutaneous infection with Trichophyton mentagrophytes.

We describe a healthy young woman with a localized deep dermal infection on the right side of the chest wall. It was caused by the dermatophyte Trichophyton mentagrophytes, and resolved after two pulses of oral itraconazole 200 mg twice daily for 1 week. As cultural and microscopic features did not enable a precise identification of the fungus, molecular investigation was undertaken. Patterns of HaeIII restriction digests of genomic DNA from the culture matched those from Arthroderma incurvata and A. benhamiae, which is the teleomorph of T. mentagrophytes var. mentagrophytes.

Administration, Oral↗
PubMed1999

Eosinophilic cellulitis following the lines of Blaschko.

Eosinophilic cellulitis is an inflammatory dermatosis of unknown aetiology. We describe a case following the lines of Blaschko, which may be the expression of cutaneous mosaicism, suggesting a possible underlying genetic predisposition for the development of Wells' syndrome.

Administration, Oral↗
PubMed1999

Major histocompatibility complex (MHC) class II polymorphism and paternity in the monogamous Hypogeomys antimena, the endangered, largest endemic Malagasy rodent.

Sequence variation at a major histocompatibility complex (MHC) class II gene was examined in Hypogeomys antimena, a monogamous endemic rodent of Madagascar. The study was conducted throughout its remaining geographical range (20 x 40 km) by direct sequencing and single-strand conformation polymorphism (SSCP). The objectives of the study were: (i) to investigate levels of polymorphism in the MHC complex of a highly endangered species that experienced a severe reduction in population size; and (ii) to investigate the genetic mating system by assessing the frequency of extra-pair paternity (EPP) as EPP might have important consequences to increase gene flow and, therefore, genetic variability within a population. The amplified gene segment had a very low variability (only two alleles) in H. antimena compared with other mammalian species. The alleles segregated consistently with Mendelian expectations in families. No case of EPP was found. The present data suggest no difference between the social and the genetic mating system.

Animals↗