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Biomedical subjects

W Thoma

Publications and source records attributed to W Thoma.

At least 19 recordsLinked to original sources
PubMed2005

Pityriasis versicolor alba.

Pityriasis versicolor alba is a hypopigmented or depigmented variant of pityriasis versicolor characterized by maculous, partly pityriasiform, scaly depigmented lesions occurring particularly in seborrhoeic areas. Long-persisting hypopigmentation after healing of the pityriasis versicolor was first described by Gudden in 1853. Hypopigmentation and depigmentation were later differentiated as an independent variant of the disease. In 1848, Eichstedt recognized the pathogen-related character of pityriasis versicolor in its hyperpigmented form. Today it is generally accepted that the disease is caused by yeasts of the genus Malassezia, of which nine species are differentiated. It is controversial whether a single species is responsible for the disease. The pathogenesis of depigmentation has not been established. A screening effect by the scale layer as well as toxic effects on pigment synthesis by fungal metabolites have been discussed. With regard to the second mechanism, the newly discovered tryptophan-derived metabolites of M. furfur might be significant. Evidence-based data concerning the therapy of pityriasis versicolor alba do not exist. According to current recommendations, pityriasis versicolor should be rapidly treated with antimycotics, followed by ultraviolet therapy to induce maturation of existent melanosomes and accelerate repigmentation. However, depigmented lesions are difficult to improve by ultraviolet therapy.

Antifungal Agents↗
PubMed2004

[Cutaneous alternariosis. Clinical diagnosis and therapeutic options].

Localized skin infections caused by the pigmented fungi of the genus Alternaria are being increasingly observed. In the past, primarily patients receiving long-term glucocorticoid therapy were likely to have this mycosis, which is commonly traumatic, but now it is frequently encountered in organ transplantation patients. Possible therapeutic options and differential diagnosis are discussed by means of two case reports--a female renal transplant patient infected by A. alternata and a patient with iatrogenic Cushing syndrome infected by A. infectoria. Histopathological differentiation from other fungal infections may be difficult but is of therapeutic and prognostic significance. Finding short hyphae in tissue sections is an important clue. Since A. infectoria shows little conidial growth in culture, rDNA ITS sequencing offers another diagnostic possibility. Therapy has not yet been standardized. Along with surgical intervention, systemic itraconazole is the usual choice.

Aged↗
PubMed2004

Prevalence of fungal foot infections in patients with diabetes mellitus type 1 - underestimation of moccasin-type tinea.

In diabetic patients, mycotic infections may increase the risk of developing diabetic foot syndrome. However, few data are available on the prevalence of fungal foot infections in patients with diabetes. During a conference attended by patients with long-term diabetes, 95 individuals with type 1 diabetes mellitus (52 men, 43 women, mean disease duration 35.8 years) were examined for fungal infections of the feet. As well as frequency of infection and risk profiles, the level of patient awareness and preventive measures taken were assessed by means of a questionnaire. Clinically, 78 patients (82.1 %) showed probable pedal fungal infections, of which 84.6 % (66/78) were mycologically confirmed by direct microscopy and/or culture. Skin mycoses were found in 9 patients (toe webs 5, soles 4), onychomycosis in 29 patients and simultaneous infection of nails and skin in 28 patients (toe webs 8, soles 20). Thirty-seven (47.4 %) of these patients had positive cultures, particularly for the dermatophyte Trichophyton rubrum (69.2 % of isolates). A significant correlation was found between infection and gender (men more frequently affected) and the age of the patients. The actual frequency of mycoses was underestimated by the patients. This correlated with the assessment of their own knowledge level concerning fungal infections: 83.2 % of patients with skin mycoses and 88.4 % of those with onychomycosis of the feet felt that they needed more information about their disease. Marked mycoses on the soles were often considered to be dry skin by the patients. The high number of infections detected is especially remarkable in that this group of patients were highly motivated. It therefore appears that diabetics require more diagnostic, therapeutic and preventive care in terms of mycotic diseases than has been previously thought.

Dermatomycoses↗
PubMed2001

Malassezin--A novel agonist of the arylhydrocarbon receptor from the yeast Malassezia furfur.

The yeast Malassezia furfur converts tryptophan into several indole compounds. One of these, malassezin, was identified as 2-(1H-indol-3-ylmethyl)-1H-indole-3-carbaldehyde (1). It was synthesized from N-Boc-indole-3-carbaldehyde in five steps with 12% overall yield. The compound easily cyclizes to indolo[3,2-b]carbazole (7) which is known to interact with the arylhydrocarbon receptor (AHR). Similarly, malassezin was found to induce cytochrome P450 as an agonist of AHR (EC50 = 1.57 microM) in rat hepatocytes.

Animals↗
PubMed2000

[Computer-assisted implant positioning in knee endoprosthetics. Kinematic analysis for optimization of surgical technique].

Modern approaches in knee endoprosthetics using computer-assisted navigation systems are based on matching procedures which refer to osseous anatomical landmarks. However, surface replacement techniques require a correct position of the implants in relation to the bone, as well as an optimal postoperative interaction of the ligaments and the surface design of the endoprosthesis. Functional aspects are of elementary importance. Insufficient design of the prosthetic surface or incorrect implantation overstresses ligamentous structures and result in functional disturbance, increased wear, and early loosening of the components. The present computer model permits a quantitative analysis of different implant positions. Distal positioning of the femoral component or insufficient resection of the tibial plateau results in a lag of extension. Increased distal resection of the tibial plateau produces marked translatory instabilities in the sagital plane which exceed the absolute height of the resection in millimeters. Monocondylar replacements with preservation of the ACL react kinematically more sensitively than bicondylar endoprostheses sacrificing the ACL. The results of this study are systematically summarized in an algorithm and indicate correction steps in order to avoid functional impairment. The computer model delivers in addition some basic data for optimized navigation procedures in knee surgery and demonstrates the importance of further developments in custom-made endoprosthetics.

Algorithms↗
PubMed2000

[Custom-made knee endoprosthetics using subtraction data of 3-dimensional CT scans. A new approach].

A new method is presented which allows the construction and implantation of highly precise custom-made endoprostheses for knee joints. The procedure is based on a computer-aided subtraction process of three-dimensional CT data. Using the differences of the CT scans, the endprosthetic components are modelled by means of a newly developed software package. The implants are manufactured by CNC machines and stereolithography. The method enables the surgeon to reduce bone resections and ensures an exact profile of the bone-implant interface. Incorrect positioning will be avoided and the implantation process can be performed more easily while the size of the operative approach will be minimized. Better postoperative kinematics and reduction of shearing effects will lead to better results in the long run. The procedure offers a series of new possibilities to optimize monocondylar and bicondylar knee joint endoprostheses.

Arthroplasty, Replacement, Knee↗
PubMed1999

[Structural requirements of computer-based medical documentation in a hospital setting].

During the last years physicians are confronted with a significant increase of their duties in clinical documentation. By law the medical diagnoses and procedures were linked with the aspect of liquidation. In consequence it is very important that physicians work out a detailed list of options concerning the features of the medical database, which has to cover the complete clinical data input and deliver flexible utilities for detailed evaluation. Beside documentation the system has to perform as an essential tool of clinical organisation and quality control to optimize the medical and commercial efficiency of the hospital. An open interface technology should be postulated to avoid a stand alone system in the long run.

Databases as Topic↗
PubMed1998

[Synthesis of fluorochromes and pigments in Malassezia furfur by using tryptophan as the single source of nitrogen].

A new minimal medium consisting only of L-tryptophan (L-trp) and a lipid source induced formation of brown pigmentation only in the species Malassezia furfur. Strains of the species M. sympodialis and M. pachydermatis failed to grow on this medium. Pigmentogenesis was already induced in M. furfur by 0.01 g% tryptophan, the pH optimum was pH = 5. Alternative amino nitrogen sources given concurrently with trp suppressed pigmentogenesis. The extract of the culture exhibited remarkable fluorescence, and several indole derivatives with a broad spectrum of colors were detected by means of mass spectroscopy and NMR. This finding may have an impact on the clinical appearance of pityriasis versicolor, a very common skin disease caused by lipophilic yeasts of the genus Malassezia. We hypothesize that in pityriasis versicolor metabolic adaptation of Malassezia yeasts to altered nitrogen conditions on superficial skin might be of pathophysiological importance. Tryptophan as inductor of pigmentogenesis probably cumulates during excessive sweating, a well known manifestation factor of pityriasis versicolor.

Dermatomycoses↗
PubMed1992

[Analysis of isokinetic and isometric muscle function after arthroscopic anterior cruciate ligament repair].

Following anterior cruciate ligament replacement plasty performed via arthroscopy, isokinetic and isometric power data were measured at the beginning and end of a sports therapy treatment course. Evaluation yielded surprising results that were partly contradictory to those communicated in current literature. Besides the dependence of force values on preset velocities of motion in dynamic measurements (isokinetics) or in static measurements (isometrics), markedly lower losses of power than expected were measured in the involved extremity on repeated power application. Possible reasons are discussed on the basis of specific innervation criteria and polymodal reflexes. We assume that muscle potential is not yet fully available after surgical intervention, due to reflexive modulations of power realisation, so that the joint and especially the anterior cruciate ligament are thus protected from damage.

Adult↗
PubMed1989

[Is there a specific cerebral organic psychosyndrome following craniocerebral trauma in childhood and adolescence? Neuropsychological and psychopathologic results].

The main clinical features pertaining to the concept of the "psycho-organic syndrome" (POS) were investigated in a sample of children who suffered from severe craniocerebral trauma. The results of the present study failed to confirm the existence of a typical syndrome following cerebral trauma. As 69% of the children had psychiatric disorders, the risk for developing psychiatric disorders was significantly increased in children who had incurred a cortical injury. However, the symptomatology turned out to be nonspecific both in terms of neuropsychological and psychopathological sequelae. Thus, the notion of a unique POS was not supported by our study. Instead our results indicated that the concept should be reevaluated. Beyond that, our results demonstrated how important it is to assess the various behavioral and psychological functioning variables exactly, particularly because of their impact on rehabilitative treatment.

Adolescent↗
PubMed1983

Gas phase formation and Doppler monitoring during decompression with elevated oxygen.

Subjects in 150 man-dives were precordially monitored with a 5-MHz Doppler ultrasound bubble detector. These measurements were made during a series of dives conducted to test decompression tables that utilize changes of breathing mixtures and a time-average PIO2 of 1.9 b during the entire decompression period. Precordially detected bubbles at depth were predictive for limb pain in divers approximately 50% of the time; however, 70% of the divers encountered bends problems in the absence of precordially detectable bubbles. Thus, while the presence of venous return bubbles can be associated with a risk factor for bends, the Doppler method appears to lack the specificity needed for personal dive monitoring. During the oxygen-breathing portions of the decompression individual bubbles could not be detected precordially. The amplitude of the Doppler-detected pulmonary artery flow sound increased, however, and possibly indicated the presence of numerous microbubbles.

Decompression↗
PubMed1981

[Fasciitis necroticans -- erysipelas grangrenosum: two different clinical entities? (author's transl)].

Among the bacterial infections of the skin the so called fasciitis necroticans has until now received little attention in dermatological literature. The clinical picture shows great similarity to erysipelas grangrenosum. Considering the fact, that the primary infection involves the subcutaneous fatty tissue and especially in light of the different bacterial etiology with the resulting differences in therapy, it seems justified to classify fasciitis necroticans as a separate entity.

Adult↗
PubMed1977

[Comparative radiological and morphological study of the human pancreas. 2. Morphometrical investigation of the human pancreatic duct system (author's transl)].

The diameter and the thickness of all the side ducts were measured in 27 normal or nearly normal human pancreata. The obtained data (about 5,000 pairs of Figures) were evaluated statistically. The relative thickness of the walls increases with growing distance from the papilla as well as with the reduction of the diameter of the side ductes. Beyond the age of fifty the diameter of the ducts is 10--13% higher than in younger age. In a logarithmical system there is a strong correlation between the diameter and the thickness of the side ducts, slightly diminished with aging. The regression coefficient is slightly diminished with aging. But the variance of the wall thickness in respect to the diameter of the ducts shows such a rise with aging, that the number of ducts with relatively thick and small walls increase with aging. By reason of the logarithmic system the positive variance has a higher weight. Therefore periductal fibrosis increases with aging.

Adolescent↗