Search PubMed⌕ Search

Biomedical subjects

R Schmidt

Publications and source records attributed to R Schmidt.

At least 307 records · Page 17Linked to original sources
PubMed1996

Sociodemographic predictors and concurrent validity of the Mini Mental State Examination and the Mattis Dementia Rating Scale.

The Mini Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (MDRS) are among the most commonly used screening tests for dementia. The goals of our study were, firstly, to identify sociodemographic factors which may explain the variance of test results in a community sample and, secondly, to investigate the interrelationship of these two dementia screening tests in order to evaluate the concurrent validity. A total of 1947 subjects were investigated in the setting of the Austrian Stroke Prevention Study (ASPS). Our study confirms most previous results demonstrating a relationship of higher dementia test scores with both younger age and higher educational level. Interestingly, the results we obtained suggest only a weak relationship and poor concurrent validity of the two tests. The total scores of the two tests show poor joint variance. This could lead to the conclusion that these tests evaluate different cognitive domains.

Age Factors↗
PubMed1996

Superficial siderosis of the central nervous system: MRI findings and clinical significance.

We reviewed a 7-year series of brain MRI examinations to determine the frequency and clinical significance of superficial siderosis of the central nervous system (SS). SS was defined by widespread bilateral signal loss at the surfaces of the cerebral or cerebellar hemispheres, the brain stem and the spinal cord on T2-weighted images. Clinical data comprised a neurological examination of identified patients and a review of their case notes. Among 8843 consecutive studies we identified 13 (0.15%) patients with MRI evidence of SS. Only 2 had symptoms or signs characteristic of SS, such as cerebellar ataxia, hearing loss, myelopathy and dementia. Haemosiderin deposition was most widespread in both symptomatic individuals. A definite cause for SS was detected in 9 patients (69%). None of them had a full clinical picture of SS. These data indicate SS per se to be much more frequent than may be assumed from the literature. It appears to become symptomatic only with extensive amounts of widespread iron deposition which develop preferentially with cryptic or unidentified causes of bleeding.

Adult↗
PubMed1996

Magnetic resonance imaging and spectroscopy of progressive cerebral involvement in Kearns Sayre Syndrome.

Kearns Sayre Syndrome (KSS) belongs to the group of so called 'mitochondrial encephalopathies'. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) may have the potential to noninvasively detect and monitor disease specific cerebral involvement, as we wish to demonstrate in a patient whom we have followed for 3.5 years. At first presentation with incomplete external ophthalmoplegia, ptosis, pigmentary retinopathy and impaired hearing MRI demonstrated ill defined areas of symmetric T2-prolongation in the dorsal parts of the mesencephalon, the pons and in both cerebellar hemispheres. While the patients clinical symptoms deteriorated, including the onset of dysphagia, signal abnormalities spread downwards into the medulla oblongata involving the glossopharyngeal nuclei and supratentorially into the white matter. Proton MRS performed with the PRESS sequence (TR/TE 1500/136 ms) in the area of white matter damage showed a doublet at 1.33 ppm, which is characteristic for the presence of lactate. Our findings suggest MRI abnormalities to increase in parallel with neurologic progression of KSS and confirm the utility of 1H-MRS in supporting mitochondrial respiratory chain insufficiency as the underlying cause of parenchymal alterations.

Adult↗
PubMed1996

The relation of cerebral magnetic resonance signal hyperintensities to Alzheimer's disease.

To further elucidate the relation of cerebral magnetic resonance signal hyperintensities to Alzheimer's disease (AD) we performed a case-control comparison between 30 consecutive patients with probable AD (age range 49-76, mean 65 years) and 60 asymptomatic volunteers matched for age, sex, and major cerebrovascular risk factors. We used a 1.5T magnet and determined the extent of morphologic abnormalities both by visual grading and measurement. AD patients showed comparable grades of deep/subcortical white matter hyperintensities (WMH) and a similar extent of the total WMH area as controls (3.3 cm2 +/- 8.8 vs. 2.0 cm2 +/- 4.6). They had significantly more often a "halo' of periventricular hyperintensity (PVH) (p < 0.0005) and an increased mean PVH thickness (3.0 mm +/- 1.9 vs. 1.3 mm +/- 1.2; p < 0.001). This PVH thickness correlated significantly with measures of ventricular enlargement. While univariate logistic regression also suggested a significant association of PVH thickness with a diagnosis of AD this association was lost against atrophy measures in a multivariate analysis. Our results confirm a significantly greater extent of PVH in AD patients than controls even when matched for cerebrovascular risk factors. However, this abnormality was not independently related to the disease but rather appears to be an epiphenomenon of brain atrophy.

Aged↗
PubMed1996

Mini mental state examination: influence of sociodemographic, environmental and behavioral factors and vascular risk factors.

Age and education have been found to affect the Mini Mental State Examination (MMSE) score of elderly normals, but there have been no studies assessing the influence of environmental and behavioral factors on this test. We therefore administered the MMSE to 1437 normal elderly subjects in the setting of a stroke prevention study and correlated their results to 16 sociodemographic, environmental, and behavioral factors, and vascular risk factors. Study statistics composed of a multiple logistic regression analysis and graphical models revealed the relations between variables in greater detail. Logistic regression yielded education level, occupational status, living as a single, general life stress, physical strain, and physical inactivity to be independent predictors of the MMSE score. Age was not included in this model. Graphical models demonstrated similar results, but did not include living as a single and physical inactivity. As shown in our independence graph, general life stress is the crucial predictor and links other environmental and sociodemographic variables with the test performance of elderly normals.

Aged↗
PubMed1996

Neutrontherapy in soft tissue sarcomas: a review of European results.

The purpose of this publication is to review the data on European neutrontherapy facilities in the treatment of soft tissue sarcoma. Data on 1171 patients treated at 11 centers were analyzed. Neutrontherapy was of advantage especially for patients with primary radiotherapy of inoperable tumors, and those with macroscopic disease after surgery. Local control was about 50% in these groups. Results for postoperative neutrontherapy after R0 and R1 resection were similar to those for photon therapy. The incidence of late side effects was considerable. This was influenced by the fact that most patients were treated with first-generation machines.

Disease-Free Survival↗
PubMed1996

BNCT as a boost for fast neutron therapy?

The thermal neutron flux in a fast neutron therapy treatment unit is measured by a small ionization chamber coated inside with boron (10B). These measurements are compared with calculations of the thermal neutron flux made by a pencil beam algorithm, which can be used as a first approximation for treatment therapy planning. The additional dose for boron neutron capture therapy (BNCT) as a boost in a 14 MeV neutron generator is calculated from the measured thermal neutron flux.

Algorithms↗
PubMed1996

Pathophysiologic features of a pneumoperitoneum at laparoscopy: a swine model.

OBJECTIVE: The aim of this study was to examine local and systemic reactions of the body to a pneumoperitoneum to elucidate potential dangers and risks of laparoscopic procedures. STUDY DESIGN: Laparoscopy was performed on 25 pigs. The pigs were divided into five groups by level of intraabdominal pressure (14 and 18 mm Hg) and gas used (carbon dioxide and air). The effects of the pneumoperitoneum on cardiopulmonary condition and the peritoneal milieu were observed. These effects should be the result of various changes as the mechanical, ventilatory, cellular, hormonal, and immunologic levels. RESULTS: In this animal study marked changes in the peritoneal milieu were observed, and we demonstrated that these changes were dependent on the gas used, intraabdominal pressure, and duration of application. Locally these changes are manifest in the development of severe peritoneal acidosis, hypercapnia, and the release of various mediators. Systemic changes, in particular cardiopulmonary changes, also depend on the intraabdominal pressure and the gas used. CONCLUSION: During conventional pneumoperitoneum the peritoneum might change to a large extent so that the development of new risks are possibly encouraged. A reduction in intraabdominal pressure with the use of carbon dioxide as the insufflation gas should result in normal acid-base balance.

Abdomen↗
PubMed1996

Detailed description of four YAC contigs representing 17 Mb of chromosome 4 of Arabidopsis thaliana ecotype Columbia.

The detailed arrangement of 563 YAC clones comprising four contigs covering approximately 17 Mbp of chromosome 4 is presented. YAC clones were positioned relative to each other and to markers by taking into account marker and end fragment hybridization data and the sizes of all YAC clones. This analysis made it possible to estimate physical distances between the majority of chromosome 4 markers. It also identified a relatively large number of YAC clones containing chimaeric inserts. The YAC contig map of the Columbia ecotype presents an important resource for map-based cloning experiments, rapid mapping of DNA sequences and large-scale genomic sequencing programs.

Arabidopsis↗
PubMed1996

[Physicians as patients--on the problem of the mentally ill physician].

The phenomenon of mentally ill physicians is hardly noticed in Germany today-a fact that possibly indicates a taboo. This investigation is to reveal the importance of the subject by referring to the findings of several major studies. Epidemiological data turn out to be of little reliability regarding for instance the number of impaired physicians with a range between 0.5-46%. Addiction and substance abuse can be found in 90% of all cases of mental illness. Increased suicide (3-4x), divorce (20x) and addiction rates (according to some authors 30-100x) in comparison with the average population emphasise the necessity of further investigation. These facts imply the question whether doctors are mentally more vulnerable than their patients. Special difficulties in treating doctor-patients deserve attention as only little is known how appropriate "iatrotropic" (psycho-)therapy can be carried out effectively.

Alcoholism↗
PubMed1996

Effects of monophosphoryllipid-A on the immunization of mice with keyhole limpet hemocyanin- and muramyldipeptide-ganglioside Gfpt1 conjugates.

Since it was considered that an active immunization against ganglioside Gfpt1 (IV2Fuc-, II3NeuAc-Gg4Cer) expressed by human small cell lung cancer cells may be beneficial in the treatment of this neoplasm in humans, an optimal mode of vaccination in model mice was investigated. A novel Gfpt1-muramyldipeptide conjugate (Gfpt1-MDP) was synthesized. Its ganglioside carbohydrate-directed immunogenicity in mice as measured by serum antibody titers was comparable to that of the previously described Gfpt1-keyhole limpet hemocyanin conjugate (Gfpt1-KLH). Similar immunogenicity was displayed by free Gfpt1 in muramyldipeptide-phosphoethanolamine-containing phosphatidyl-choline, -serine (PC,PS) liposomes. Immunization with Gfpt1-vaccines in the presence of monophosphoryllipid A (MPL), in general, raised titers of anti-Gfpt1 antibodies effectively. Immunization with PC, PS-liposomes containing unconjugated Gfpt1 and MPL stimulated the highest titers observed, thereby effectively preventing tumor growth in Balbc nu/nu-mice challenged with human small cell lung cancer cells. However, there was a strong crossreaction of these and most other sera with the structurally related and widely distributed ganglioside Gtet1 (II3NeuAc-Gg4Cer). Only immunization with Gfpt1-KLH conjugate in the presence of MPL stimulated selectively high anti-Gfpt1 antibody titers showing comparably low crossreactivity to ganglioside Gtet1.

Adjuvants, Immunologic↗
PubMed1996

Keloid excision and recurrence prophylaxis via intradermal interferon-gamma injections: a pilot study.

Keloids are an abnormal response to wound healing distinguished by an overproduction of collagen. Thickened bundles of collagen in the reticular dermis oriented haphazardly in relation to the overlying epithelium are found in keloids, in contrast to thinner collagen fibers in a more orderly arrangement that are found in normal scars. Previous clinical trials of intralesional interferon-gamma (IFN-G) injections by Larrabee et al. and Granstein et al. showed a decrease in lesion size. These findings led to a conclusion that IFN-G would be a useful adjunct to surgical excision of keloids to aid in preventing recurrence. We performed a double-blind, placebo-controlled trial in patients with two or more keloids treated with excision and subsequent local injections of IFN-G or placebo.

Adolescent↗
PubMed1996

Pattern of cerebral blood flow and cognition in patients undergoing chronic haemodialysis treatment.

We studied 20 patients aged 46-69 years (mean 57 years) undergoing long-term haemodialysis (HD) and 20 age- and sex-matched controls with single photon emission tomography (SPET) and 99Tcm-hexamethyl-propyleneamine-oxime to look for regional abnormalities in cerebral blood flow (CBF) and their relation to cognitive dysfunction. Global hemispheric tracer uptake relative to the cerebellum was similar in both groups, but regional over cerebellar activity was significantly reduced in the frontal cortex (85.9 +/- 5.1 vs 90.4 +/- 5.3; P = 0.01) and thalamus (99.2 +/- 8.8 vs 104.9 +/- 8.4; P = 0.05) of the HD patients. Normalization to whole-brain activity also showed the frontal cortex to be hypoactive in the HD patients, while tracer uptake was increased occipitally. These regional differences were not explained by the presence of atrophy or cerebrovascular damage seen on brain magnetic resonance imaging. The HD patients scored significantly worse on cognitive tests such as the Mini Mental State Examination (23 +/- 4 vs 28 +/- 1; P < 0.001) and Mattis Dementia Rating Scale (114 +/- 24 vs 143 +/- 1; P < 0.001). Regional activity ratios did not correlate with cognitive test scores, however. Our results indicate a disturbed pattern of CBF in HD patients, although regional SPET abnormalities did not correspond to the severity of cognitive dysfunction.

Aged↗
PubMed1996

Apolipoprotein E e4 allele in the normal elderly: neuropsychologic and brain MRI correlates.

The presence of the apolipoprotein E e4 allele has been considered to be a risk factor for Alzheimer's disease and vascular dementia. We therefore used demanding neuropsychologic testing and brain MRI to determine if elderly normals with at least one e4 allele demonstrate subclinical changes in cognition and a higher frequency of brain atrophy or silent ischemic brain damage. The study population consisted of 214 randomly selected individuals aged 50 to 75 years without neuropsychiatric or general disease. There were 175 (81.8%) subjects without and 39 (18.2%) with at least one e4 allele. The two groups were comparable for age, length of education, verbal intelligence, mood and major vascular risk factors. Apolipoprotein E e4 carriers performed significantly worse than non-carriers when assessed for learning and memory abilities, while there were no differences in test results of conceptualization, attention, speed of mental processing and visuopractical skills. There were no between-group differences for thromboembolic and lacunar infarcts, white matter hyperintensity grading and the semiautomatically measured white matter hyperintensity area. The extent of sulcal and ventricular widening as well as hippocampal and parahippocampal volumes were also similar between the comparative subsets. We conclude that the apolipoprotein E e4 allele is associated with subtle learning and memory deficits in normal elderly persons and may therefore be suggested a marker for accelerated cognitive aging. In this group of subjects it was not associated with brain parenchymal changes as demonstrated by MRI.

Aged↗
PubMed1996

Cyclic morphiceptin analogs: cyclization studies and opioid activities in vitro.

Attempts were undertaken to develop cyclic beta-casomorphin-5 analogs with improved opioid activity profiles by deletion of the glycine residue in position 5, leading to analogs structurally related to the opioid peptide morphiceptin (H-Tyr-Pro-Phe-Pro-NH2). The tetrapeptide sequence Boc-Tyr(tBu)-D-Xaa-Phe-Yaa-OH (Xaa = Lys, Orn, A2bu; Yaa = Pro in L- or D-configuration) was used to study the influence of ring size and chirality on the yield of cyclization between the omega-amino group of Xaa and the C-terminal carboxyl group. In all cases the cyclization reaction was performed under identical experimental conditions to allow a direct comparison with regard to yield and homogeneity. The reaction products were purified by crystallization and liquid chromatography, and were characterized by HPLC, TLC, electrospray mass spectrometry and 1H-NMR spectroscopy. In none of the reactions performed with the cyclization precursors containing proline in the L-configuration could a cyclic monomer be detected, and the cyclodimer (7-9) was the exclusive product in each case. Cyclodimerization was also the favored reaction in the attempted formation of the 11-membered ring of the cyclic [D-A2bu2, D-Pro4]-morphiceptin analog 12, since only traces of the monomer were found. In the case of both the [D-Lys2, D-Pro4]-analog 10 and the [D-Orn2, D-Pro4]-analog 11, the cyclomonomer/cyclodimer ratio was about 80:20. The cyclic monomers 10 and 11 showed high opioid activity in the mu-receptor-representative guinea pig ileum assay (IC50 = 2-5 nM) and in the delta-receptor representative mouse vas deferens assay (IC50 = 50-60 nM), whereas the potency of the cyclodimers was 2-3 orders of magnitude lower in both in vitro bioassays.

Analgesics↗