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Biomedical subjects

R Schwarz

Publications and source records attributed to R Schwarz.

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

[Clinical studies in liver transplantation].

Clinical liver transplantation became an established therapy of end-stage liver disease since the first at least medium-term successful liver transplantation in 1967. Clinical studies have played a major part in improving peri- and postoperative therapy in liver transplantation. In this article clinical studies of major impact are presented. Main topics are studies dealing with immunosuppressants, improvements in surgical techniques, viral infections and tumor diseases. Controlled randomized multicentric studies are rare; most of the studies are unicentric. Further studies in the fields of reducing side effects of immunosuppression, the introduction of monoclonal antibodies and improvement of the therapy of viral hepatitis would be helpful. These studies should be controlled, randomized and multicentric.

Carcinoma, Hepatocellular↗
PubMed2000

Acute rejection of hepatic allografts from HLA-DR13 (Allele DRB1(*)1301)-positive donors.

Acute rejection of hepatic allografts does not show consistent association with the number of mismatches of HLA classes I and II. Therefore, we investigated the relation between specific donor or recipient HLA antigens and the occurrence of acute rejection. HLA typing of 35 liver transplant recipients and donors was performed by serological standard technique, with confirmation and subtyping by polymerase chain reaction with sequence-specific primers. HLA class I antigens were not associated with the occurrence of acute rejection. The graft was positive for HLA-DR13 in 8 of 13 transplant recipients (62%) with acute rejection, but only 4 of 22 recipients (18%; P =.024; P(Bonferroni-corrected) =.33, not significant) without rejection. The graft was positive for DRB1*1301 in 7 of 13 recipients (54%) with acute rejection, but only 1 of 22 recipients (5%) without rejection (P =.002; P(Bonferroni-corrected )=.028). This patient had experienced long-lasting bacterial sepsis, which markedly reduced the risk for acute rejection. We speculate that the expression of donor DRB1*1301 (if mismatched) may increase the risk for acute hepatic allograft rejection.

Acute Disease↗
PubMed2000

[Attitude of medical students toward the handicapped].

In their daily professional work physicians are increasingly faced with persons who live with chronic diseases or handicaps. Beyond profound medical knowledge, an understanding of psychosocial factors and a positive attitude are essential for providing optimal treatment. In order to teach the medical students of Leipzig University how to balance these factors they are required to visit self-help groups and institutions for disabled persons as part of the course "Social Medicine". 250 medical students of the 9th semester filled out a questionnaire designed to assess their attitudes toward handicapped persons as well as their motivation for choosing the medical profession. The questionnaire was given twice, once before their visitations and once following. 28 students of special supportive education served as a control group. While the attitudes of the medical students were very similar to those of the standard population, the attitudes of the supportive education students were significantly more positive. A comparison of the results of the questionnaires before and after the visitations showed that the attitudes of the medical students remained essentially the same without any obvious changes due to their experiences during the visitations. This evidence suggests that there needs to be more emphasis in Social Medicine and medical education in general placed on the problems specific to handicapped people.

Adult↗
PubMed2000

The sinus hair follicle of the cat. Hair growth and hair cycle.

The cat's sinus hair follicle is described histologically with special regard to structural characteristics and functional mechanisms of sinus hair growth and sinus hair cycle. Special features of both cornification of the inner epithelial root sheath and hair fixation, respectively, result in a loss of traction that is required for hair growth and hair expulsion. Instead, there is the outgrowing new anagen sinus hair that pushes the preceeding sinus hair upwards, and - secondly - there is a long-lasting cell pro- liferation. Cell proliferation - immunocytochemically detected with anti-proliferating cell nuclear antigen - continues in the preceeding sinus hair while the formation of a new, succeeding sinus hair follicle begins. No distinct, 'typical' catagen state of sinus hair follicle has been found even in a large number of collected specimens. These findings stress that the well known features of hair growth and hair cycle in the pelage hair follicle cannot be generalized and adopted in all details to the sinus hair follicle.

Animals↗
PubMed2000

[Not Available].

Epidemiological data show that 40-50% of all cancer patients develop some kind of psychosocial disturbancy during the course of their illness and about 30% will require professional support. Even if there exists a considerable body of knowledge and a differentiated health care System, the vast majority of cancer patients have no chance to receive any proper psychosocial care due to the lack of facilities like psychosocial outpatient Services in the communities and specifically trained psychooncologists on oncology wards, whereas the number of psychooncologists in rehabilitation-clinics seems to be sufficient. Psychooncological societies have established training courses and formulated guidelines relating to some important aspects of psychosocial research and practice, in order to promote good quality in the psychosocial care of cancer patients.

Cancer rehabilitation↗
PubMed2000

[Not Available].

Oncologists have been reluctant a long time to accept the existence of spontaneous remissions in cancer disease. The considerable number of patients whose cancer-disease has regressed without (adequate) treatment should have allayed these doubts. Such remissions could serve as a kind of natural experiments that may lead to greater insights in the biology of tumours and to more efficient therapeutic strategies. In the moment the discussion deals with the explanation of spontaneous remissions by the existing biological or psychosomatic theories. Whereas the fact of spontaneous remissions was denied on the one hand some people claim the occurrence of such remissions for themselves without justification. In order to obtain an epidemiological register of these cases it would be necessary to document all patients in question in a standardised manner. Such a set of data should include psychosocial variable as well since the psychosomatic approach seems to be even more in danger of speculations that resemble closely the causal attributions of the patients.

Causal attributions↗
PubMed1999

19F-MRI of perfluorononane as a novel contrast modality for gastrointestinal imaging.

19F-Magnetic resonance imaging in conjunction with perfluorononane provides a new modality for gastrointestinal (GI) imaging as is demonstrated here with an animal model. Perfluorononane was found to be an ideal oral contrast agent since it is biologically inert, immiscible with water, and since it has a low viscosity and surface tension. Furthermore, its high fluorine content, together with the high sensitivity of 19F-MRI, allowed highly selective MR images of the GI tract of mice to be acquired. Due to the lack of 19F background signals, the contrast of the GI tract was only limited by the signal-to-noise ratio of the 19F-MR images. 19F-RARE images of 1-mm slices with an in-plane resolution of 0.23 x 0.23 mm2 were obtained from the GI tract after oral perfluorononane administration. The passage of perfluorononane through the entire GI tract was monitored by repetitive MR measurements with a maximal time resolution of 38 s. The three-dimensional surfaces of the GI tract were reconstructed and superimposed on corresponding 1H-MR images, which provided complementary anatomical information.

Administration, Oral↗
PubMed1999

[Results of radiotherapy for vertebral hemangioma].

PURPOSE: Assessment of treatment results of symptomatic vertebral hemangiomas and review of the literature (Table 3). PATIENTS AND METHODS: Ten patients treated between 1974 to 1997 were retrospectively analyzed. Efficacy of treatment was determined according to improvement of pain and/or neurological symptoms (Table 1). RESULTS: Improvement was achieved in 8 of 10 patients. The initially existing neurological symptoms of 3 patients disappeared completely in 2 cases and improved in 1 case. Acute side effects were slight. Late side effects were not seen. A dose-effect relationship could not be assessed. There was no relapse. CONCLUSION: Radiotherapy with 30 Gy for symptomatic vertebral angioma as primary therapy is indicated. In case of neurological symptoms a radiotherapy after operative therapy is recommendable even if the patient is free of symptoms to prevent progress or relapse.

Adult↗
PubMed1999

[Behavioral therapeutic methods in ambulatory treatment of alcoholism. Early results of an experimental study].

Outpatient alcoholism treatment programs are widespread especially in the United States and in Great Britain. However, there still exist only a few experimental studies investigating the numerous questions arising from this field. In this still ongoing project 120 patients were randomly assigned to 3 different outpatient group therapy programs: unspecific supportive therapy and 2 forms of behavioural therapy--coping skills training [17] and cognitive therapy according to Beck [2]. The main hypotheses to be tested are that both forms of behavioural therapy will prove superior to supportive treatment and that patients with a comorbidity of personality disorders will profit in a different way from these differentiated intervention strategies. Treatment lasted 6 months; first results obtained after the termination of this period demonstrate the feasibility of the study design; patients undergoing behavioural therapy showed good compliance with few drop-outs and significantly higher rates of abstinence compared with supportive therapy. 60% of the patients suffer from a concomitant personality disorder (mostly of the dependent, insecure, and masochistic type). Nevertheless, statistically significant differences between the 2 behavioural therapy techniques could not be established; a positive correlation between personality disorders and relapse or attrition could be confirmed only for relapses occurring within the first 3 months of treatment.

Adaptation, Psychological↗
PubMed1998

A response regulator of cyanobacteria integrates diverse environmental signals and is critical for survival under extreme conditions.

Microorganisms must sense their environment and rapidly tune their metabolism to ambient conditions to efficiently use available resources. We have identified a gene encoding a response regulator, NblR, that complements a cyanobacterial mutant unable to degrade its light-harvesting complex (phycobilisome), in response to nutrient deprivation. Cells of the nblR mutant (i) have more phycobilisomes than wild-type cells during nutrient-replete growth, (ii) do not degrade phycobilisomes during sulfur, nitrogen, or phosphorus limitation, (iii) cannot properly modulate the phycobilisome level during exposure to high light, and (iv) die rapidly when starved for either sulfur or nitrogen, or when exposed to high light. Apart from regulation of phycobilisome degradation, NblR modulates additional functions critical for cell survival during nutrient-limited and high-light conditions. NblR does not appear to be involved in acclimation responses that occur only during a specific nutrient limitation. In contrast, it controls at least some of the general acclimation responses; those that occur during any of a number of different stress conditions. NblR plays a pivotal role in integrating different environmental signals that link the metabolism of the cell to light harvesting capabilities and the activities of the photosynthetic apparatus; this modulation is critical for cell survival.

Amino Acid Sequence↗
PubMed1998

[Radiotherapy of soft tissue sarcomas].

Soft tissue sarcomas are uncommon neoplasms that represent approximately 1% of all malignancies. It is clear that sarcomas require a therapeutic approach that establishes local control and thereby eliminates the potential of metastasis for patients with truly limited disease. Localized sarcomas are generally treated by surgery. Excision must be complete, with a wide margin of normal tissue, and along anatomic planes, or recurrence will almost certainly follow. Amputations are still occasionally required, although limb salvage procedures are being used increasingly, particularly in the context of multimodality therapy with irradiation or chemotherapy. Radiotherapy can be highly effective for improving local control and is used as adjuvant therapy, either preoperatively or postoperatively. In case of non-in-sano-resection a salvage surgery is indicated. Use of adjuvant postoperative radiotherapy allows for more conservative surgery without compromising local control, and therefore often may allow limb salvage where amputation might otherwise be necessary, e.g. in case of R1- or R2-resection without a new resection, a close margin or large tumors with histologic G2 or G3 grading and in case of local relapses. Local control rate of 90% are reported for the combination of pre- and postoperative radiotherapy. Prognosis is still limited by distant metastases. In case of unresectable tumors neutron radiotherapy results in 50% local control. New approaches e.g. hyperfractionated-accelerated radiotherapy, interoperative radiotherapy and chemoradiotherapy are promising perspectives, which are being evaluated in clinical studies. Desmoid tumors benefit of postoperative radiotherapy in case of R1-resection or relapse.

Combined Modality Therapy↗
PubMed1998

Neutron therapy in malignant salivary gland tumors: results at European centers.

Malignant salivary gland tumors are relatively rare and account for only 3%-4% of all head and neck cancers. Especially in adenoid cystic carcinoma, the incidence of local recurrence and distant metastases is influenced by the perineural spread of tumor. In advanced salivary gland tumors, surgery alone has a high incidence of local failure. The results of conventional radiotherapy are suboptimal in inoperable or not completely resected salivary gland tumors and in recurrent disease. The pooled data of some international series for low linear energy transfer radiation show a local control of only 28%. Especially in advanced salivary gland tumors, neutron therapy can improve local control. In Europe at least 570 patients with salivary gland tumors have been treated with neutrons alone or with combined modalities. The clinical data of different centers in Europe and the United States result in a similar local control rate of 67% in gross disease. An analysis of different European series shows on average a complication rate of 10.6% for severe radiation-related morbidity. Modern neutron machines and the use of three-dimensional treatment planning systems are now available in a few institutions and may further reduce side effects.

Aged↗
PubMed1998

European results of neutron therapy in soft tissue sarcomas.

The purpose of this publication is to review the data of European neutron therapy facilities in the treatment of soft tissue sarcoma. In the past locally advanced soft tissue sarcoma was a common indication for neutron therapy in several European centers. Data from 1171 patients treated at 11 centers were analysed on the basis of published data or personal communication. Neutron therapy was of benefit especially for patients with primary radiotherapy of inoperable tumors, and with macroscopic disease after surgery. Local control was about 50% in these patients. These results are superior to those from photon therapy from the literature. Results for postoperative neutron therapy after R0- and R1-resection are similar to those from photon therapy. The incidence of late side effects was considerably high in some neutron series. This is influenced by the treatment of most patients with first-generation machines of limited technical standard, and that in most cases large treatment volumes were irradiated.

Humans↗
PubMed1998

[The results of radiotherapy in meningiomas with a high risk of recurrence. A retrospective analysis].

AIM: Retrospective assessment of the efficacy of radiation therapy for meningiomas with high risk for local recurrence. PATIENTS AND METHODS: Records of 67 patients with meningiomas treated from 1974 to 1995 at 2 centres were analyzed. Follow-up time ranged from 0.8 to 213 months (median: 61 months). Radiation therapy was given either after local failure or after biopsy or subtotal resection. The ratio between malignant (n = 20) and benign (n = 47) meningioma was 1:2.4. Median age of the patients was 55 years (7 to 77 years). Radiation treatment was given at 1.5 to 2 Gy per fraction to 36 to 79.5 Gy. Survival rates were calculated by the Kaplan-Meier method. Statistical comparisons were performed with the log-rank test and the Cox proportional hazards model. The Bonferroni method was used to correct for multiple comparisons. RESULTS: Five- and 10-year disease-free survival rates were 82% +/- 5% (standard error) and 70% +/- 9%. Local control rates at 5 and 10 years were 78% +/- 5% and 68% +/- 9%. In uni- and multivariate analysis histology, sex, total dose and center showed no significant influence on the results. Patients age was significant for local control (univariate p = 0.02; multivariate p = 0.03) and disease-free survival (univariate/multivariate p = 0.04). The postoperative tumor burden had a significant influence of disease-free survival (multivariate p = 0.04). After Bonferroni correction no significant influence was observed. We did not observe late side effects, especially brain necrosis. CONCLUSIONS: Despite of the negative selection of our patients we observed high survival- and local control rates after radiation therapy. This underscores the role of radiation therapy in the treatment of meningiomas with high risk of local failure.

Aged↗
PubMed1998

Survival in patients with primary soft-tissue sarcomas treated within 6 years.

Since 1988, treatment strategies for our sarcoma patients have been determined by the same team and operations performed by one surgeon. The aim of this study was to analyse prognostic data on local recurrence and survival of 101 consecutive patients who presented in our institution with the primary tumour manifestation. After a median follow-up of 35 months, the local recurrence rate was 13.5%, the mean survival time was 68 months and the 5-year survival rate was 83%. Besides positive lymph nodes (only 3 patients) the quality of resection significantly influenced local recurrences (P < 0.05). Univariate predictors of mortality were tumour grade (P < 0.01), tumour size (P < 0.05), distant metastases (P < 0.01), and resection quality (P < 0.01). Multivariate predictors of mortality consisted of grade (P < 0.0001), positive lymph nodes (P < 0.001) and resection quality (P < 0.01). In this homogeneous group of patients, excellent recurrence and survival rates could be achieved. An optimized surgical treatment not only reduces the rate of local recurrences but also augments survival time.

Adolescent↗