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Biomedical subjects

W Spitzer

Publications and source records attributed to W Spitzer.

At least 19 recordsLinked to original sources
PubMed2004

Possibilities and limitations of current stereo-endoscopy.

BACKGROUND: Stereo-endoscopy has become a commonly used technology. In many comparative studies striking advantages of stereo-endoscopy over two-dimensional presentation could not be proven. To show the potential and fields for further improvement of this technology is the aim of this article. METHOD: The physiological basis of three-dimensional vision limitations of current stereo-endoscopes is discussed and fields for further research are indicated. New developments in spatial picture acquisition and spatial picture presentation are discussed. RESULTS: Current limitations of stereo-endoscopy that prevent a better ranking in comparative studies with two-dimensional presentation are mainly based on insufficient picture acquisition. CONCLUSION: Devices for three-dimensional picture presentation are at a more advanced developmental stage than devices for three-dimensional picture acquisition. Further research should emphasize the development of new devices for three-dimensional picture acquisition.

Depth Perception↗
PubMed2002

Comparison between three-dimensional presentation of endoscopic procedures with polarization glasses and an autostereoscopic display.

BACKGROUND: Most endoscopic procedures are done with a two-dimensional (2D) view or a spatial presentation with polarization glasses. A new method of presenting three-dimensional (3D) spatial views is the autostereocopic display. We compared the performances of untrained test persons using these methods. METHODS: We designed three tests that had to be performed with one of the presentations. We used a Karl Storz 3D set with a 0 degrees stereooptic and a grasper. The autostereoscopic display was the Dresden 3D display. The 59 test persons were students who had never before worked with endoscopic devices. RESULTS: There were few differences between the tests, and none were statistically significant. The results with 2D were slightly better than those with polarization glasses, and the results with polarization glasses were slightly better than those with the autostereoscopic display. CONCLUSIONS: There are few differences between the procedures. A true spatial view is limited by the similarity of the two half-pictures.

Depth Perception↗
PubMed1998

Nodal CT density and total tumor volume as prognostic factors after radiation therapy of stage III/IV head and neck cancer.

PURPOSE: To determine whether the immunohistochemical expression of proliferation-associated antigens (proliferating cell nuclear antigen, MIB1) and the nuclear p53 reactivity in addition to total tumor volume, nodal CT density and T and N category are predictive for overall survival and locoregional tumor control in patients with squamous cell carcinoma of the head and neck region. MATERIALS AND METHODS: Between October 1989 and September 1993, 87 patients with biopsy proven head and neck cancer were randomly allocated to receive radiation alone or simultaneous radiation and chemotherapy as part of a multicenter trial with a total of 298 randomized patients. There were only inoperable lesions in UICC (1992) stage III (8%) and IV (92%). Radiotherapy was delivered with 180 cGy twice daily up to a total dose of 7020 cGy in 51 days. Three cycles of 2340 cGy each were separated by a rest period of 11 days. Chemotherapy consisted of cis-DDP, 5-fluorouracil and leucovorin and was repeated on days 22 and 44. Routinely-processed paraffin-embedded sections were stained using monoclonal antibodies for detection of proliferation-associated antigens (MIB1 and PCNA) and p53 oncoprotein to determine the labeling index (LI). In addition, the total tumor volume and the percentage of necrosis were measured using CT data. The median follow-up was 3.9 years (range 1.9-5.0 years). RESULTS: The overall survival and locoregional control for all 87 patients were 34 and 39% at 3 years, respectively. The addition of chemotherapy resulted in a better overall survival (27 versus 47%, P = 0.03) but did not influence locoregional control (31 versus 47%, P = 0.08). In univariate analysis, nodal CT density (P < 0.0001), total tumor volume (P < 0.0001), age (P = 0.001) and the MIB1-LI (P = 0.04) had a significant impact on overall survival. However, in the final Cox model only the nodal CT density (P = 0.0003) and age (P = 0.05) were independent prognostic factors for survival and only the nodal CT density (P = 0.0006) was an independent prognostic factor for locoregional control. The expression of the p53 oncoprotein was not found to have a clear predictive value. CONCLUSION: Nodal CT density, total tumor volume and age will remain the relevant prognostic factors in stage III/IV head and neck cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Low-dose iloprost infusions compared to the standard dose in patients with peripheral arterial occlusive disease Fontaine stage IV. DAWID Study Group.

BACKGROUND: Intravenous iloprost, titrated from 0.5 up to 2.0 ng/kg/min has been shown in patients with PAOD III/IV to significantly improve healing of trophic lesions, relief of rest pain, and reduce the rate of major amputation or death at 6 months as compared to placebo. The effect is considered related to improvement of the microcirculation. The aim of the present trial was to identify an optimum dose regarding treatment response and tolerability, by studying 4 doses of 25, 50, 75 and 100 micrograms iloprost daily. PATIENTS AND METHODS: 302 patients with PAOD IV were randomised via a double-blind fashion to one of the 4 doses. The primary endpoint was the responder rate at end of treatment. Responders were defined as patients with very good or good global efficacy, as judged by lesion healing and pain relief. Side effects were documented and a pre-defined benefit/risk index was calculated. RESULTS: No dose-dependency of iloprost regarding primary or secondary endpoints was observed. The rate of responders ranged between 48.7-53.5%. Side effects, mainly related to vasodilation, increased dose-dependently (p < 0.001, chi 2-test), with a significant decrease of the benefit/risk index from 2.19 +/- 1.19 to 1.64 +/- 0.97 (p = 0.012, ANOVA). Responders had a better outcome at 6 months than non-responders (2.6 fold higher rate of major amputation or death; life table analysis). CONCLUSIONS: It is concluded that iloprost should be titrated to the optimum rather than maximum tolerated dose, since a higher incidence of side effects not associated with an increased treatment response was observed at higher doses.

Aged↗
PubMed1997

The hospital social work self-efficacy scale: a partial replication and extension.

The Hospital Social Work Self-Efficacy Scale (HSWSE) was developed to assess social workers' confidence about their ability to perform hospital social work. The scale was originally tested with master's-level social work students. This partial replication and extension included both students and professional social workers. In addition, we used a new scale to assess construct validity and added another hospital to assess external validity. In general, findings continue to support the use of the HSWSE. In addition, anecdotal evidence suggests that this is an outcome measure that practitioners see as easy to use, specific, and highly relevant.

Educational Measurement↗
PubMed1991

Clinical complexity and epidemiologic uncertainty in case-control research. Fenoterol and asthma management.

Two recent epidemiologic case-control studies suggested that fenoterol, a selective beta-adrenergic agonist, was associated with an increase in the risk of asthma death. The results of these studies were criticized because of methodologic problems in the choice and selection of control subjects; the different methods used to gather exposure data in cases and control subjects; and because of inadequate classification and adjustment for asthma severity. In response to this controversy, a new study is underway, the Saskatchewan Asthma Epidemiology Project. The SAEP includes two complementary studies, an historic cohort and a case-control analysis, that employ the computerized databases of the Saskatchewan Health Department. A unique aspect of the SAEP is the attempt to incorporate knowledge of asthma physiology and management into the design of the studies. Specifically, the study design recognized the role of antiinflammatory drugs in asthma treatment; the distinction between asthma death and near-fatal asthma; the severity of asthma; patterns of drug use; and the distinction between inadequate clinical care and disease severity. The strategies we employed in the SAEP may prove helpful to investigators whenever clinical and biologic processes create sources of potential bias requiring special procedures for the design and analysis of epidemiologic studies.

Adolescent↗
PubMed1991

[Therapeutic approaches for patients with cleidocranial dysostosis].

In three cases of c.c.d. it could be shown, that combined orthodontic and surgical treatment provided further possibilities for the treatment of severe problems in permanent dentitions as well as correcting extreme skeletal discrepancies of the facial skeleton in c.c.d. Well-scheduled removal of supernumerary teeth creates space for the spontaneous eruption of delayed teeth. By the use of carefully applied orthodontic forces, alignment of even extremely displaced teeth is shown to be possible. Furthermore, it is demonstrated that careful planning and realization of osteotomies in the midface can remarkably improve the facial appearance and the relationship of the jaws thus facilitating particularly future prosthodontic treatment.

Adolescent↗
PubMed1990

Reaction of mastication to occlusal changes induced by correction of mandibular prognathism.

Incisor-point masticatory movements of 22 patients were recorded before and after correction of mandibular prognathism. Chewing patterns and movement parameters were compared between preoperative and postoperative states and to corresponding quantities of 85 persons with normal dentitions. The prognathism patients most frequently revealed "chopping-type" patterns characterized by nearly vertical closing strokes, whereas mastication in the reference group was dominated by lateral grinding-type movements. There were no significant differences in the pattern distributions and parameter values between the preoperative and postoperative states. An individual assessment, considering random fluctuations of chewing behavior, showed that only five patients had changed their chewing mode possibly because of the treatment. Only a minor part of these changes could be directly related to the altered occlusion. It is concluded that the characteristic chewing mode of persons with mandibular prognathism does not interfere with the occlusal profile, and hence does not react to alterations.

Adult↗
PubMed1990

Virucidal activity of hypericin against enveloped and non-enveloped DNA and RNA viruses.

Hypericin is a polycyclic anthrone first isolated from the plant St. Johnswort and was shown to have dramatic anti-retroviral activity against Friend leukemia virus and radiation leukemia virus in mice. Hypericin displayed marginal activity (IC50 = 6 micrograms/ml) against Moloney murine leukemia virus (Mo-MuLV) in vitro. Hypericin did not display selective antiviral activity against herpes simplex virus, influenza A, adenovirus, or poliovirus. The 50% cytotoxic concentration was approximately 25 micrograms/ml. When virus was incubated with hypericin before infecting cells, the drug was virucidal to all enveloped viruses tested (herpes simplex, influenza virus A, and Mo-MuLV) at concentrations of 1.56 micrograms/ml to 25 micrograms/ml. Hypericin was not virucidal to the non-enveloped viruses tested (adenovirus and poliovirus). These data indicate that the mechanism of viral inactivation for hypericin is dependent upon the presence of a viral lipid envelope. In vivo, hypericin (50 mg/ml) was effective against FLV or HSV-1 if incubated with the virus for 1 h at 37 degrees C before infecting mice, but was not effective if pre-incubated with virus for 1 h at 4 degrees C or if administered concurrently with virus.

Animals↗
PubMed1990

[Intrathecal morphine administration for oral and maxillofacial malignomas].

The intraventricular administration of morphine results in lesser systemic side effects, with an extremely satisfactorily pain relief going along with it (2, 5, 6). The subcutaneous pump which administers morphine intraventricularly is an interesting, non-destructive alternative of medium-term pain therapy for patients suffering from incurable pain caused by a malignant tumor in the oropharyngeal region. The morphine pump even makes it possible to go through terminal stages of the malignant disease well-relieved and in the familiar environment at home.

Cerebral Ventricles↗
PubMed1989

[Results of temporary interstitial iridium 192 implantation in head and neck tumors].

In order to improve local tumor control in advanced head and neck tumors, a temporary interstitial iridium-192 implantation (40 to 50 cGy/h) was performed as a boost therapy (20 to 30 Gy at the surface of the target volume). This treatment was part of a multimodal therapy conception for primary tumors (N = 55) as well as for recurrences (N = 22). Local control was achieved in 89% (49/55) of patients treated for primary tumors. Complications appeared in the form of soft tissue necroses in 55% (30/55) and in the form of osteoradionecrosis of the mandible in 7% (4/55) of the patients. The authors discuss as possible reasons for this high complication rate: implantation volume too large or total activity too high, activities of the individual iridium-192 seeds to high, setting of radiation sources too close together, total dose too high, disturbed reparation capacity of sound tissues due to preceding operation and chemotherapy, premature test biopsies in the area of implantation, lacking oral hygiene and dental care by uncooperative patients. A local control rate of 50% was achieved by the treatment of recurrences, but this has no importance for the course of this tumor disease which is fatefully determined by the formation of remote metastases.

Adult↗
PubMed1989

[Flow cytophotometric measurements before and during radiotherapy of head and neck tumors].

The DNA index and proliferation activities were determined by flow cytophotometry in 59 tumors of the head and neck area. 35 tumors (59%) were aneuploid, 24 (41%) were diploid. Aneuploid tumors showed a tendency to increased formation of lymph node metastases, an increased risk of relapse as well as a shorter relapse-free interval. No correlation was found between the primary tumor stage and the incidence of aneuploid tumors. Whereas aneuploid tumors developed frequently regional recurrences, only local recurrences were observed in diploid tumors. A number of biopsies was additionally performed during radiotherapy in twelve tumors. After 10 or 20 Gy, aneuploid tumors showed a considerably increased number of S and S2 + M phase cells. In diploid tumors, substantial modifications of the cell cycle phases were not found, because it is not possible in these cases to distinguish between normal cells and tumor cells.

Aneuploidy↗