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Biomedical subjects

T Jansen

Publications and source records attributed to T Jansen.

At least 37 records · Page 2Linked to original sources

Interactive 3D segmentation and inspection of volumetric medial datasets.

We propose an interactive method providing 3D real-time visualization of segmentation results while tuning some of the algorithmic parameters. Visual inspection in volume reduces the time spent in tuning cumbersome parameters and may increase accuracy in medical applications. To allow fast interaction, volume rendering is achieved by using 3D texture mapping. The output of the segmentation stage is then dynamically updated in the graphic pipeline through a color lookup table related to the tuned parameters. This technique enables our approach with immediate rendering of the user interaction during the segmentation. Isosurface methods and connectivity filters have been implemented with this technique. CT and MR modalities have been tested for anatomical structures extraction. For application in craniofacial surgical planning, measurements present improvement in accuracy and efficiency for 7 pathological cases. However, manual refinement is still necessary in order to realize clinical applicable 3D models.

Computer Simulation↗

Fast generation of stereolithographic models.

In this paper we present a work-in-progress method for fast and efficient generation of stereolithographic models. The overall approach is embedded in our general software framework Julius, which runs on high-end-graphic systems as well as on low-level PCs. The design of the support structures needed for the stereolithographic process will allow semiautomatic generation of the model. We did produce support structures for stereolithographic models with this fast data processing pipeline and will show future perspectives in this paper.

Computer Graphics↗

Bilateral linear scleroderma "en coup de sabre" associated with facial atrophy and neurological complications.

BACKGROUND: Linear scleroderma "en coup de sabre" (LSCS) usually affects one side of the face and head in the frontoparietal area with band-like indurated skin lesions. The disease may be associated with facial hemiatrophy. Various ophthalmological and neurological abnormalities have been observed in patients with LSCS. We describe an unusual case of LSC. CASE PRESENTATION: A 23 year old woman presented bilateral LSCS and facial atrophy. The patient had epileptic seizures as well as oculomotor and facial nerve palsy on the left side which also had pronounced skin involvement. Clinical features of different stages of the disease are presented. CONCLUSIONS: The findings of the presented patient with bilateral LSCS and facial atrophy provide further evidence for a neurological etiology of the disease and may also indicate that classic progressive facial hemiatrophy (Parry-Romberg syndrome) and LSCS actually represent different spectra of the same disease.

Adult↗

[Pemphigus vegetans. A historical perspective].

Pemphigus vegetans is a rare variant of pemphigus which is mainly localized in the intertriginous areas (Neumann type, Hallopeau type) or primarily involves the mucous membranes (pyostomatitis vegetans). A 18-year-old patient with erosive stomatitis developed a vegetating plaque with papillomatous and verruciform features in her left axilla. Histopathological examination of the axilla revealed papillomatosis and acanthosis as well as suprabasal clefting with acantholytic cells. By direct immunofluorescent examination, deposits of immunoglobulin IgG and complement (C3) were found in the intercellular space of the epidermis. Serological examination by indirect immunofluorescent techniques was indicative of pemphigus autoantibodies at a titer of 1:40. This case report demonstrates that the classical differentiation of pemphigus vegetans in two types, Neumann type and Hallopeau type, is mainly of historical importance, because both entities may represent variants of the same disease. In addition, other disorders such as IgA pemphigus may also present with vegetating plaques in intertriginous sites.

Adolescent↗

Rosacea-like demodicidosis associated with acquired immunodeficiency syndrome.

We present a 35-year-old patient with acquired immunodeficiency syndrome who had demodicidosis on his face, characterized by multiple papules and papulopustules, associated pruritus, numerous mites on skin-surface biopsy and in biopsy specimens, and rapid response to topical treatment with permethrin. It seems likely that Demodex infestation does not manifest unless local or systemic immune function is altered, leading to the proliferation of the organism and subsequent disease.

AIDS-Related Opportunistic Infections↗

Low-dose ultraviolet-A1 phototherapy for lichen sclerosus et atrophicus.

Lichen sclerosus et atrophicus (LSA) is a chronic inflammatory skin disease characterized by white porcelain-like sclerotic skin lesions. It is most commonly seen in adult females and usually affects the genitoanal area. Extragenital LSA appears in 15-20% of cases. We report a 9-year-old Caucasian girl suffering from extragenital LSA that was resistant to conventional treatment. After 40 treatment sessions with low-dose UVA1 phototherapy, all skin lesions were resolved completely. Moreover, the improvement of skin status has been sustained during 6-months of follow-up. Long-wave UVA irradiation has been shown to induce intensively collagenase activity in human dermal fibroblasts. We suggest that UVA1 irradiation could be an effective treatment in patients suffering from extragenital LSA.

Child↗

Rosacea fulminans triggered by high-dose vitamins B6 and B12.

Rosacea fulminans is a rare variant of rosacea conglobata that occurs almost exclusively in women well past adolescence. The aetiology is unknown, although immunological, hormonal, and vascular factors have been suggested. We report the case of a 17-year-old girl with rosacea fulminans that was temporally associated with daily ingestion of high-dose vitamin B supplements. The onset was sudden and cosmetically disabling. The eruption improved when the vitamin supplement was discontinued and a therapeutic regimen including isotretinoin and methylprednisolone was introduced. It seems appropriate to consider the possibility of such a vitamin B-triggered condition in cases of subjects presenting new or exacerbating facial eruptions.

Adolescent↗

[Anatomy of the shoulder joint].

The shoulder joint and its associated joints form one of the most complex joint systems of the human locomotor apparatus. Its large range of motion is made possible by the interplay of 5 joints: sternoclavicular-joint, acromioclavicular-joint, glenohumeral joint, thoracoscapular joint and subacromial joint. The rotator cuff works mostly as an active stabilizer of the shoulder joint. The supraspinatus muscle causes a compression of the humerus in the glenoid mainly, furthermore it effects synergistic the abduction with the delta muscle. On the basis of its lever-arm the supraspinatus works between 0 and 60 degrees abduction the most optimally. With failure of the supraspinatus, the deltoideus can almost completely take its function. The inferior glenohumeral ligament-complex is the main passive stabilizer. The blood supply of the humerus head is ensured mainly by the a. circumflexa anterior and its rami ascendents, by several small branches from the a. circumflexa posterior and over intraosseous anastomoses. The most important vessel of the cap is the intraosseous a. arcuata out of the ramus ascendens lateralis of the a. circumflexa anterior.

Acromioclavicular Joint↗

Extensive partial unilateral lentiginosis.

Partial unilateral lentiginosis is a rare pigmentary disorder characterized by multiple lentigines on otherwise normal skin affecting one side of the body. The histology is that of a lentigo. We report two young men with an extensive form of partial unilateral lentiginosis affecting the skin. No systemic abnormalities could be identified.

Adult↗

Effect of genetically modified Pseudomonas putida WCS358r on the fungal rhizosphere microflora of field-grown wheat.

We released genetically modified Pseudomonas putida WCS358r into the rhizospheres of wheat plants. The two genetically modified derivatives, genetically modified microorganism (GMM) 2 and GMM 8, carried the phz biosynthetic gene locus of strain P. fluorescens 2-79 and constitutively produced the antifungal compound phenazine-1-carboxylic acid (PCA). In the springs of 1997 and 1998 we sowed wheat seeds treated with either GMM 2, GMM 8, or WCS358r (approximately 10(7) CFU per seed), and measured the numbers, composition, and activities of the rhizosphere microbial populations. During both growing seasons, all three bacterial strains decreased from 10(7) CFU per g of rhizosphere sample to below the limit of detection (10(2) CFU per g) 1 month after harvest of the wheat plants. The phz genes were stably maintained, and PCA was detected in rhizosphere extracts of GMM-treated plants. In 1997, but not in 1998, fungal numbers in the rhizosphere, quantified on 2% malt extract agar (total filamentous fungi) and on Komada's medium (mainly Fusarium spp.), were transiently suppressed in GMM 8-treated plants. We also analyzed the effects of the GMMs on the rhizosphere fungi by using amplified ribosomal DNA restriction analysis. Introduction of any of the three bacterial strains transiently changed the composition of the rhizosphere fungal microflora. However, in both 1997 and 1998, GMM-induced effects were distinct from those of WCS358r and lasted for 40 days in 1997 and for 89 days after sowing in 1998, whereas effects induced by WCS358r were detectable for 12 (1997) or 40 (1998) days. None of the strains affected the metabolic activity of the soil microbial population (substrate-induced respiration), soil nitrification potential, cellulose decomposition, plant height, or plant yield. The results indicate that application of GMMs engineered to have improved antifungal activity can exert nontarget effects on the natural fungal microflora.

Antifungal Agents↗