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Biomedical subjects

A Wittmann

Publications and source records attributed to A Wittmann.

At least 19 recordsLinked to original sources
PubMed2002

Systematic muscle building exercises in the rehabilitation of stroke patients.

The effects of targeted strength training in patients with muscle weakness of central origin following cerebrovascular accidents has hardly been investigated to date. This prospective non-randomized study of 56 patients was designed to shed light on the effects of strength building exercises on muscle tone and on the gain in muscle strength achieved with them. All patients underwent a full residential neurologic rehabilitation program for 4 weeks, which included an exercise program for restoring the extensor strength of the legs and the supporting strength of the arms by leg and arm presses. Throughout the rehabilitation program muscle spasticity was evaluated clinically and maximal muscle strength on completion of the exercise program was compared to baseline. The extensor strength of the legs increased by 31.0 (+/- 26.7)% by 40.2 (+/- 15)%. significant for both variables. The extent of strength gain was positively correlated with the intensity and the number of exercising units. Muscle tone, which was abnormally high at baseline, did not further increase in any one case. The results of this study showed that targeted strength training significantly increased muscle power in patients with muscle weakness of central origin without any negative effects on spasticity.

Adult↗
PubMed2001

Construction of a computed tomographic phantom for a Japanese male adult and dose calculation system.

Computational human phantoms have been widely used to estimate organ doses and other dosimetric quantities related to the human body where direct measurements are difficult to perform. In recent years, voxel phantoms (voxel = volume element) based on computed tomographic (CT) data of real persons have been constructed which provide a realistic description of the human anatomy. A CT phantom of a Japanese male adult with an average body size was developed as the first Asian voxel phantom. The segmented phantom consists of more than 100 regions enabling the calculation of doses for various parts of the body. The bone marrow distribution was precisely modelled according to the CT values. The EGS4 Monte Carlo transport code was combined with the phantom to calculate organ doses for external exposure due to photons and electrons up to 1 TeV. The calculated organ doses were compared with respective data using MIRD-type mathematical phantoms. In some cases, significant discrepancies in doses were observed, demonstrating the necessity of sophisticated models for accurate dose calculations.

Adult↗
PubMed2001

The adult male voxel model "Golem" segmented from whole-body CT patient data.

This paper describes the construction of an adult male voxel model named "Golem" intended to be used for Monte Carlo simulations to calculate dosimetric quantities for radiation protection considerations. The model was segmented from whole-body medical image data of a living person who was 38 years old and had external dimensions close to those of the ICRP Reference Man. The segmentation process using dedicated image processing hard- and software is described and the resulting model is characterised with respect to weight and height of the total body, organ and tissue masses and red bone marrow distribution. A comparison with the respective data for ICRP Reference Man and three further voxel models is presented. Golem was found to agree reasonably well with Reference Man, so that he can be used for the assessment of "representative" body doses.

Adult↗
PubMed1998

Body composition in an employee health improvement program.

We checked the change in health status of employees of an Austrian company over a period of one year. In June 1995 medical and anthropometric tests were carried out. From the results of the tests, we made individual recommendations for training and nutrition. Lectures, demonstration sessions and regular sessions in gymnastics were held during the year. In June 1996 a re-test was carried out. In 1995, 95 men and 27 women, in 1996, 62 men and 27 women participated in the investigation. A comparative statistical analysis was carried out for the group of men. Body fat tissue decreased and fat free mass increased highly significantly (p = 0.000), systolic blood pressure decreased about 10 mmHg on average (p = 0.000), exhalation volume as well as the relative physical work capacity increased very high significantly (p = 0.000 for both parameters). There were no significant changes of diastolic blood pressure, glucose, cholesterol and triglyceride levels.

Adipose Tissue↗
PubMed1997

Comparison of adrenoceptor subtype expression in porcine and human bladder and prostate.

We have quantified and characterized alpha 1-, alpha 2- and beta-adrenoceptor subtypes in porcine bladder detrusor and bladder neck, human bladder detrusor, and porcine and human prostate. alpha 1-, alpha 2- and beta-adrenoceptor were identified in radioligand binding studies using [3H]prazosin, [3H]RX 821002 and [125I]iodocyanopindolol, respectively, as the radioligands. In porcine male and female detrusor and bladder neck and male prostate, adrenoceptors were detected in the order of abundance beta > alpha 2 >> alpha 1 (not detectable), with no major difference between the sexes or between detrusor and bladder neck. In human detrusor and prostate the order of abundance was beta > alpha 2 >> alpha 1 (not detectable) and beta >> alpha 1 > alpha 2, respectively. The alpha 2-adrenoceptors in all tissues were homogeneously of the alpha 2A-subtype as evidenced by competition binding studies with yohimbine, prazosin, ARC 239 and oxymetazoline. The beta-adrenoceptors represented a mixed population with a dominance of the beta 2-subtype in all tissues as demonstrated by competition binding with ICI 118,551 and CGP 20,712A. We conclude that pigs may be a suitable model for studies of detrusor function with respect to adrenoceptor expression. They may be less suitable for studies of bladder neck or prostate function.

Adrenergic alpha-1 Receptor Agonists↗
PubMed1997

Is the expression of multidrug resistance gene product a prognostic indicator for the clinical outcome of patients with renal cancer?

OBJECTIVE: To determine the significance of the expression of the multidrug resistance gene product (MDR-1) for the aggressiveness of renal cell carcinoma (RCC). PATIENTS AND METHODS: The study comprised 31 patients with clinically locally confined RCC treated with radical nephrectomy (mean age 64.1 years, range 41-78; mean follow-up 5.4 years, range 4.3-7.3). Their survival time and disease-free period were evaluated retrospectively. The expression of the MDR-1 gene product was determined immunohistochemically using the JSB-1 antibody in formalin-fixed paraffin-embedded tumour samples from these patients. The significance of this variable and tumour stage and malignancy grade was assessed for predicting the survival and disease-free period using Kaplan-Meier plots (log-rank test or Tarone's test) and the Cox multiple hazard regression analysis. RESULTS: In a univariate analysis, tumour stage (P < 0.002), malignancy grade (P < 0.007) and MDR-1 (P < 0.03) were significant prognostic variables for both survival and disease-free period. Lower MDR-1 expression was correlated with poorer prognosis. On multivariate analysis, MDR-1 and tumour stage were significant factors for predicting the disease-free period, whereas tumour stage and malignancy grade were the most relevant factors for survival time. Calculating prognostic indices based on the results of the Cox analysis, MDR-1 could replace malignancy grade, resulting in a better prediction of survival and disease-free period (P < 0.001 vs 0.0031, P < 0.001 vs 0.021, respectively). CONCLUSION: MDR-1, an established predictor for chemo-resistance, may also be a potent prognostic factor for outcome in patients with locally confined RCC. Moreover, MDR-1 expression seems to correlate with the differentiation of the RCC and thus its value as an objective measure of the degree of differentiation should be further explored.

Adult↗
PubMed1996

AIDS, emergency operations, and infection control.

Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) may turn out to be the largest lethal epidemic of infection ever. The estimated global number of HIV-infected adults in 1993 was 13 million, with projections of up to 40 million by the year 2000. Human immunodeficiency virus infections and AIDS are relevant to surgeons with respect to the surgical management of AIDS patients in general, the treatment of the increasingly long list of surgical complications specific to AIDS patients in particular, and the risks of patient-to-surgeon and surgeon-to-patient HIV transmission. Because of migration of individuals and populations throughout the world, even surgeons practicing in relatively unaffected regions should be familiar with the potential surgical implications of AIDS. Ethical considerations arise, as well. Are surgeons obliged to operate on HIV-positive or AIDS patients? Some surgeons adhere strictly to the Hippocratic Oath, whereas others reserve the right to be selective on whom they operate, except in emergencies. Other common ethical considerations in the AIDS patient are similar to those arising in the terminal cancer case: whether to operate or not; whether to provide advanced support such as total parenteral nutrition or hemodialysis. Answers are not simple and require close collaboration between the surgeon, the AIDS specialist, and involved members of other specialties. Emergency operations become necessary to treat AIDS independent disease such as acute cholecystitis and appendicitis or AIDS-related life-threatening conditions such as gastrointestinal bleeding, obstruction, perforation, or ischemia complicating Kaposi's sarcoma, lymphoma, and cytomegalovirus or disseminated nontuberculous mycobacterial infections. Delays and errors in diagnosis are frequent. Poor nutritional state with weight loss, low serum albumin, and leukocyte count prevails in most patients requiring emergency operations and account for a high mortality. By applying solid judgment and selecting management appropriately, the surgeon has the ability to prolong life and to improve the quality of life for these unfortunate patients, and to do so with extremely minimal risk to himself and his team.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Realistic computerized human phantoms.

To estimate the risk resulting from exposures to ionizing radiation, the organ and tissue doses should be assessed. A convenient method is the calculation of these doses using representations of the human body, called models or phantoms, together with computer codes simulating the transport of radiation in the body. Most commonly used are mathematical phantoms whose external and internal volumes are defined by simple geometric bodies. More recently, phantoms constructed from computed tomographic data of real persons were introduced as an improvement. These phantoms present advantages concerning the location and shape of the organs, in particular the hard bone and bone marrow, whose distribution can be assessed with high resolution. So far, three of these phantoms were constructed at the GSF, a fourth is under process. The construction technique is described, and some calculational results of organ doses due to external photon irradiation are presented.

Adult↗
PubMed1989

A comparative study of the tissue-destroying effect of the laser and electrocoagulation.

The effect of the laser on compact, glandular tissue at the dosage employed for the local palliative treatment of tumors, can largely be mimicked with the aid of high-frequency current (HF-current), applied with the aid of an electro-hydro-thermo-probe: The experiments described in the present study were performed on the livers of 70 male Wistar rats. The laser was applied for 2 seconds at an output of 80 J at a distance to the tissue of 0.5 cm. In the first stage, in the acute experiment, the effect of the HF-current was matched to that of the laser by varying the modulated and unmodulated current components. It was found that the depths of penetration into the tissue at the given laser settings could be achieved with modulated HF-current (so-called coagulation current) at an output of more than 72 watts (equipment setting K 10) coagulation being performed for 10 seconds. The admixture of modulated HF-current (so-called cutting current) reduces the depth of penetration into the tissue. In the first 5 days, the depth of penetration increases after both laser irradiation and HF-coagulation, by a factor of 2 to 3. With respect to the depths of penetration (DP), the scatter ranges, and the histological changes, no difference is to be seen between laser and HF lesions: Laser DP = 5.7 mm (confidence range: 4.4-7.0 mm); HF DP (equipment setting K 10) = 4.8 mm (confidence range: 3.6-5.4 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Multiplanar imaging of the temporal bone. Initial results].

In the head and neck area CT imaging (particularly the HR-technique) is a well-established diagnostic procedure. Besides other locations it has been successfully used in the preoperative evaluation of the temporal bone. Nevertheless, the sophisticated anatomy of this special area is hard to interpret in certain cases. In the present study we report on our preliminary results in producing a multiplanar reconstruction of the area mentioned above. Temporal bones were used that had been excised during autopsy. The specimen were examined under a CT imager of the 3rd generation with a high-resolution mode. Sections of 1 mm thickness were obtained. For the evaluation a surface model was used; the segmentation was carried out mainly automatically. The surface was calculated using a triangulation algorithm. The obtained data enabled us to receive three-dimensional aspects of the temporal bone; these reconstructions could be examined from any desired perspective. Our results indicate that the multiplanar reconstruction might be of great importance for the diagnostic evaluation of temporal bone diseases in the future. In the meantime several technical problems have to be solved to guarantee a sufficient quality of the reconstructed specimen.

Computer Simulation↗
PubMed1988

[Simultaneous intra- and extrauterine pregnancy].

A case is reported of simultaneous intrauterine and extrauterine pregnancy, accompanied by a right tubal pregnancy and rupture in the 8th week of gestation and a spontaneous parturition in the 42nd week. Frequency and aetiological factors, as well as diagnostic possibilities and differential diagnostic considerations are discussed.

Adult↗