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Biomedical subjects

R Schmidt

Publications and source records attributed to R Schmidt.

At least 397 records · Page 22Linked to original sources
PubMed1994

The Mattis Dementia Rating Scale: normative data from 1,001 healthy volunteers.

We administered the Mattis Dementia Rating Scale (MDRS) to 1,001 healthy volunteers, aged 50 to 80 years, randomly selected from our community. Multivariate regression analysis revealed educational level (p = 0.000004) and age (p = 0.00001), but no other sociodemographic or risk factors for stroke, to be significantly associated with the MDRS score. The age- and education-specific lowest quintile cutoff scores ranged from 140 in subjects aged 50 to 59 years with at least college experience to 130 in subjects aged 70 to 80 years with only 4 to 9 years of schooling. These percentile distributions obtained for decades of age and different levels of education should be useful reference values for clinicians and investigators when applying the MDRS to assess cognitive functioning.

Aged↗
PubMed1994

Present results of neutron therapy. The German experience.

Results of fast neutron therapy are reviewed with special reference to the main indications for this type of treatment and the experience of five German centers. Neutron therapy seems beneficial compared to conventional radiotherapy in advanced salivary gland tumors, inoperable or unresectable soft tissue sarcomas, some bone tumors, prostate cancer stage C and some rare low-grade tumors. About 3,000 patients with malignancies have been treated with neutrons at the German centers Berlin/Rossendorf, Essen, Hamburg, Heidelberg and Münster. Treatment results and treatment-related morbidity depend on the treatment techniques and the physical selectivity of the neutron machines. A critical appraisal suggests that fast neutrons are of advantage in about 5% of all radiotherapy patients.

Carcinoma, Non-Small-Cell Lung↗
PubMed1994

[The effect of nimodipine on cochlear blood flow in the guinea pig].

The influence of nimodipine (Nimotop, CAS 66085-59-4), a selectively cerebrovascularly acting 1,4-dihydropyridine calcium antagonist, on the cochlear blood flow (CBF) was studied in 19 guinea pigs (6 controls). The hydrogen clearance measurements were carried out under alpha-chloralose-ethylurethane anaesthesia, artificial respiration with simultaneous control of electrocardiogram, blood pressure, body temperature and arterial pH (hourly). The indirect measurement of CBF was carried out by means of hydrogen clearance in the perilymphatic space (basal turn) before and after intravenous application of 1 microgram nimodipine/kg/min. The mean arterial blood pressure remained within the +/- 5% range of the initial value during the experiment. Under treatment with nimodipine the CBF showed a non-significant average increase of 4.69% and under placebo (20% ethanol, 17% polyethylenglycol 400, citrate buffer), a non-significant average decrease of 6.16%. The influence of nimodipine on CBF was underlined by the overcompensation of the placebo effect.

Animals↗
PubMed1994

[Laparoscopic therapy of nonparasitic liver cysts].

Minimal invasive surgery has become an important part of surgical therapy of non-parasitic cysts of the liver. At the moment there exist only a few but in all cases positive experiences with the laparoscopic unroofing of liver cysts. Until now we treated 3 patients with non-parasitic liver cysts by means of this method. In all cases we had no intra- or postoperative complications and the average hospital stay was 5 days. In agreement with other authors we think that laparoscopic unroofing of non-parasitic liver cysts is a method with promising future. The necessity of an intraoperative cholangiography in case of a bile leak respectively recurrence prophylaxis by means of an omentum major plastic will be decided by further clinical investigation.

Biliary Fistula↗
PubMed1994

Consideration of time-dose-patterns in 3D treatment planning. An approach towards 4D treatment planning.

PURPOSE: The rendering of the 3D dose distribution together with anatomical information and the volumes of interest (VoI) is essential to get a visual impression of the treatment plan and to find modifications for the optimization of the dose distribution. The integration of biological effects into the 3D treatment planning is of interest for the assessment of different time-dose patterns. MATERIALS AND METHODS: One way of taking into account biological data is to relate the physical dose in critical structures to the corresponding tolerance dose. For that purpose the applied time-dose pattern has to be converted into the standard fractionation scheme being the basis of the tolerance dose. Generally any model can be used for these calculations. Here a modified incomplete repair model is used to calculate the relative biological dose distribution (RBD). The visualization of these biologically isoeffective dose distributions can be performed in the same manner as the physical dose so that the physical and biological dose distributions can by displayed side by side. As this is equivalent to introducing the time as a fourth dimension into 3D treatment planning this is called 4D treatment planning. RESULTS: From 3D dose matrices the biologically isoeffective dose distributions are calculated for the organs at risk. The changes introduced by different time-dose patterns are displayed using the same technique as for rendering 3D treatment plans. The visualisation of the three-dimensional biological dose distributions is shown by means of a patient with an oesophagus carcinoma. The RBD related to the tolerance dose of the organs at risk is displayed for different time-dose fractionations. CONCLUSION: The RBD distribution on a 3D treatment plan can be displayed in the same mode as the physical dose distribution. This offers additionally valuable information in a 3D treatment planning process about the dose to critical organs and the influence of different time-dose patterns.

Color↗
PubMed1994

[Protein A immunoadsorption al a new apheresis procedure for elimination of HLA antibodies].

The protein A immunoadsorption allows to remove antibodies of the classes IgG, IgM and IgA in special quantities from the plasma. IgG subclasses 1, 2 and 4 will be removed for 100% and IgG of class 3 for nearly 80%. For this reason immunoadsorptions are a useful therapeutic method especially for immunological diseases with antibodies of IgG type. The successful use of immunoadsorption in the removal of HLA antibodies in patients with acute myeloic leukemia and patients after kidney allograft is reported.

Blood Transfusion↗
PubMed1993

Screening for thyroid disorders in a working population.

Subclinical thyroid disorders have received increasing attention in recent years due to refined laboratory methods and a stronger emphasis on the role of preventive medicine. We performed a screening for thyroid-stimulating hormone (TSH) on 6884 persons in a working population. In cases in which TSH was not within the normal range we also measured the levels of triiodothyronine (T3), thyroxine (T4), and thyroxine-binding globulin (TBG). All persons who did not present with exclusion criteria or other nonthyroidal illnesses (n = 59) and the controls (n = 39) were submitted to thyrotropin-releasing hormone (TRH)-testing. Additionally, sonography of the thyroid was performed on 120 persons (59 subjects with abnormal hormone levels and 61 controls) to determine thyroid size and rule out morphological abnormalities. Based on the TRH test and T3, T4, and TBG measurements we found a prevalence of 0.03% (2/6884) for overt hyperthyroidism, 0.33% (23/6884) for subclinical hypothyroidism, 0.09% (6/6884) for subclinical hypothyroidism, and 0.015% (1/6884) for overt hypothyroidism in the healthy population. In subjects with overt or subclinical hyperthyroidism the prevalence of goiters (thyroid volume > 18 ml in women, > 25 ml in men) was 28%. Of this group 48% had structural abnormalities. All persons with goiters and/or structural abnormalities were over 35 years of age. Among the euthyroid, 20% had thyroid enlargement, and the same proportion presented with structural abnormalities. There were no differences between the two age groups. In the group with overt/subclinical hypothyroidism 47% presented with structural abnormalities of the thyroid; however, none presented with thyroid enlargement. Thyroid nodules were found only in older persons (> 35 years) with euthyroidism or hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

EEG mapping in middle aged normal volunteers: the impact of cerebrovascular risk factors.

The impact of major risk factors for stroke on EEG mapping and routine EEG findings was evaluated in volunteers with no clinical signs of cerebrovascular or other neuropsychiatric disease. Focal changes were seen in 22 subjects (30%) by means of EEG mapping, but in only 12 cases (16%) when routine-EEG was used (p < .05). 4/35 (11%) volunteers without RF had focal changes while this was seen in 18/39 (46%) subjects in whom risk factors (RF) were found (p < .01). An association was seen between the presence of EEG foci and number of RF. 59% of subjects with 2 or 3 RF had focal abnormalities as opposed to 36% of those with 1 RF and 11% of RF free individuals (p < .05). The findings could be confirmed by averaging the EEG data according to the different number of RF revealing statistically significant differences between each of the 3 groups. Using routine EEG alone no significant correlation to the presence or number of RF was found. Our data demonstrate EEG abnormalities in a considerable portion of normal middle aged individuals which in part may be attributed to the presence of RF.

Aged↗
PubMed1993

Cognitive impairment after acute supratentorial stroke: a 6-month follow-up clinical and computed tomographic study.

To document the occurrence, time course, and predictors of global cognitive impairment following a supratentorial stroke, we prospectively studied 41 consecutive patients with acute cerebral ischemia and no evidence of pre-existing intellectual disturbances. The Graded Neurologic Scale and Mattis Dementia Rating Scale were used to assess neurologic and cognitive deficits within the first week, 3 weeks and 6 months after the onset of symptoms. CT was performed at each examination and semiquantitative measurements of infarct volumes and brain atrophy were obtained. Sixty-one percent of patients were found to be cognitively impaired within the first week. After 6 months this deficit had resolved in 24%, but was still present in 37% of individuals. Initial findings associated with a high risk of long-term intellectual dysfunction were: 1. moderately severe cognitive impairment, 2. diminished alertness in the acute stroke stage, 3. infarction involving the temporal lobe, 4. evidence of multiple brain infarcts and 5. pronounced ventricular enlargement. Logistic regression analysis revealed temporal infarcts and evidence of multiple ischemic lesions as the most powerful predictors of persistent cognitive impairment. By these two factors alone, 85.4% of study participants could be correctly classified regarding their cognitive outcome. These results suggest cognitive dysfunction to be a frequent sequela of supratentorial stroke. Its long-term persistence may be predicted on the basis of certain features.

Adult↗
PubMed1993

Effects of nerve stimulation on blood flow in the urinary bladder, urethra and pelvic floor in the dog.

Pelvic organs have triple innervation from the pelvic, sympathetic and pudendal nerves. Peripheral effects can be studied by neurostimulation of the nerves, whereas the topography of the spinal cord neurons can be determined by horseradish peroxidase tracing. We have evaluated the neurophysiologic effects of the nerves at their target organs by intraoperative electric stimulation and compared the effects to the anatomical innervation areas. These zonal areas were determined by blood flow alterations, measured with nine different microspheres. Pelvic nerve stimulation showed bladder contraction with no significant blood flow changes during stimulation. Sympathetic nerve stimulation caused moderate detrusor contraction and pressure increase in the bladder neck and intraprostatic area. Regional blood flow showed a four-fold increase in the bladder neck area during neurostimulation. Pudendal nerve stimulation revealed an intraurethral pressure increase with a 3.5-fold increase of blood flow in the sphincteric area and in the pelvic floor musculature.

Animals↗
PubMed1993

Long-term cultivation of human osteoblasts.

Primary cultures of osteoblastic cells were obtained from human bone tissue after corrective surgery. Osteoblasts were isolated with a combined enzymatic and cell migration method and characterized by a high expression of alkaline phosphatase (AP), the marker enzyme for osteoblasts. For quantification of AP a new sensitive method has been developed. Also the secretion of osteocalcin measured by radioimmunoassay (RIA) which was stimulated by calcitriol, characterized isolated cells as osteoblasts. Osteoblasts isolated by the enzymatic and migration method formed 3-dimensional structures during cultivation in a mixed basal medium containing serum substitute, vitamin C and glycerophosphate. They maintained their specific cell characteristics over a period of 50 generations and did not dedifferentiate in contrast to their cultivation in medium containing fetal calf serum. Therefore a great amount of differentiated human osteoblasts could be obtained after cultivation of the primary cultures from different donors and this allows the examination of the influence of age and sex on cellular activity.

Adult↗