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Biomedical subjects

K Kunze

Publications and source records attributed to K Kunze.

At least 19 recordsLinked to original sources
PubMed2004

Element selective detection of molecular species applying chromatographic techniques and diode laser atomic absorption spectrometry.

Tunable diode laser atomic absorption spectroscopy (DLAAS) combined with separation techniques and atomization in plasmas and flames is presented as a powerful method for analysis of molecular species. The analytical figures of merit of the technique are demonstrated by the measurement of Cr(VI) and Mn compounds, as well as molecular species including halogen atoms, hydrogen, carbon and sulfur.

Chlorine↗
PubMed2001

Formation of a stable decagonal quasicrystalline Al-Pd-Mn surface layer.

We report the in situ formation of an ordered equilibrium decagonal Al-Pd-Mn quasicrystal overlayer on the fivefold symmetric surface of an icosahedral Al-Pd-Mn monograin. The decagonal structure of the epilayer is evidenced by x-ray photoelectron diffraction, low-energy electron diffraction, and electron backscatter diffraction. This overlayer is also characterized by a reduced density of states near the Fermi edge as expected for quasicrystals. This is the first time that a millimeter-size surface of the stable decagonal Al-Pd-Mn is obtained, studied, and compared to its icosahedral counterpart.

Journal Article↗
PubMed2001

Disability and quality of life in Charcot-Marie-Tooth disease type 1.

OBJECTIVES: Charcot-Marie-Tooth disease type I (CMT1) is a hereditary sensorimotor neuropathy causing variable degrees of handicap. The risk for relevant disability in respect to genetic counselling is unknown. An attempt was made to define it. METHODS: Disability and ambulation of 50 patients with CMT1 were scored by the Hauser ambulation index score and the Rankin scale. Rankin score 2 was subdivided into 2a (independent without relevant slowness) and 2b (independent, though at the cost of excessive time consumption). The sickness impact profile was assessed and compared with patients 6 months after stroke who were without mental deficit. To define at which degree sickness and disability become relevant for genetic counselling, the patients were asked whether they would refrain from childbearing if the children were at risk of inheriting a disease that caused as much disability as they experienced themselves. RESULTS: Subdivision of Rankin score 2 was reliable and improved validity. High disability significantly predicted an attitude against childbearing (stepwise logistic regression) only with this subdivision. Thirty six per cent of the patients voted against childbearing. The cut off for relevant disability in respect to childbearing was a Rankin score higher than 2a, which was present in 44% of the patients. Psychosocial impact was comparable with patients with stroke and similar disability. Depression was present in 18% of the patients. CONCLUSION: Subdivision of Rankin score 2 is recommended for the assessment of longstanding disability in neuromuscular disorders. Disability becomes relevant for the attitude towards childbearing as soon as everyday activities become markedly slow (Rankin score 2b). Relevant disability occurred in 44% of the patients. Emotional stress in CMT is similar to that of patients with stroke and comparable disability.

Adolescent↗
PubMed2001

[The DCS plate osteosynthesis of the distal femur].

The DCS is an implant to be used only in certain situations. It offers solutions when the medullar cavity is blocked by implants in the proximal femur, and in case of pathological fractures, where it is necessary to remove all cancerous tissue and to reinstate the stability of the bone through compound osteosynthesis. The DCS is absolutely necessary when there is no possibility to reconstruct the condyles with closed procedures and has the advantage of anatomical reconstruction. In the case of partly supracondylar fractures, the kneepoint is not tampered with, and by subcutaneous technique, the operation is less traumatic.

Adult↗
PubMed2000

High shear strain of olivine aggregates: rheological and seismic consequences.

High-pressure and high-temperature torsion experiments on olivine aggregates in dislocation creep show about 15 to 20% strain weakening before steady-state behavior, characterized by subgrain-rotation recrystallization and a strong lattice preferred orientation. Such weakening may provide a way to focus flow in the upper mantle without a change in deformation mechanism. Flow laws derived from low strain data may not be appropriate for use in modeling high strain regions. In such areas, seismic wave propagation will be anisotropic with an axis of approximate rotational symmetry about the shear direction. In contrast to current thinking, the anisotropy will not indicate the orientation of the shear plane in highly strained, recrystallized olivine-rich rocks.

Journal Article↗
PubMed1999

Glucocorticoid receptor concentrations in muscle biopsies from patients with neuromuscular diseases.

Increases in circulating glucocorticoids promote catabolism, particularly in skeletal muscle. The sensitivity of the muscle to glucocorticoids can be altered by a change in the number of glucocorticoid receptors in the muscle, or by a change in the proportions of activated receptors (between binders IB and II). We have investigated the concentration of glucocorticoid receptors, and the proportions of types IB and II, in healthy and diseased muscle. We found significantly reduced concentrations of glucocorticoid receptors in the group of inflammatory myopathies (51% reduction; P < 0.05, Wilcoxon signed rank test). No significant changes in the relative proportions of binders IB and II were found in pathological muscle, although the proportion of binder IB tended towards elevated values (especially in the diabetic neuropathies, with a 17% increase). We conclude that the sensitivity of muscle to glucocorticoids can be reduced in neuromuscular diseases, especially in myositis, by a reduction in the number of glucocorticoid receptors in the tissue, but that no relevant shift in the relation between activated receptor types is present. This could be important in relation to the risk of a secondary steroid myopathy and catabolism of skeletal muscle in the treatment of inflammatory myopathies with glucocorticoids.

Biopsy↗
PubMed1999

Interleukin-12 is detectable in sera of patients with multiple sclerosis - association with chronic progressive disease course?

Multiple sclerosis (MS) is widely accepted as a systemic T- cell-mediated autoimmune disease with a T-helper type-1 (TH-1) profile of cytokine production. We addressed the question whether interleukin-12 (IL-12), as a central mediator of TH-1-cell activities, is detectable in sera of MS patients, and if there is any association with disease activity. We analysed 171 sera of patients with MS and meningitis, and healthy controls. IL-12 p40 protein was detectable at low levels in MS patients (median 43 pg/ml) and controls (median 49 pg/ml). Analysing different disease courses and activities, a significant elevation in stable primary progressive MS cases compared with controls (median 66 pg/ml) was found. IL-12 p40 protein was not detectable in cerebrospinal fluid probes of 10 patients. We conclude that the function of IL-12 in MS depends on expression and degradation of the different proteins. These could act proinflammatory as well as limiting the disease process.

Adult↗
PubMed1998

Immunolocalization of leukemia inhibitory factor in normal and denervated human muscle.

The cytokine leukemia inhibitory factor (LIF) stimulates myoblast proliferation in vitro and vivo and is neurotrophic for motor neurons. In experimentally reinnervated muscle, exogenous LIF application increases muscle mass through myofiber hypertrophy. The goal of this study was to evaluate possible sources of endogenous LIF in human muscle, and whether LIF immunoreactivity (-IR) was detectable in specific myofiber types and/or re-expressed in human denervated muscle. Our study shows that LIF-IR is constitutively detectable in type I myofibers of normal human muscle. In acute and chronically denervated and reinnervated human muscle, LIF-IR is found in all type I myofibers and in addition in some atrophic and almost all angulated atrophic type II myofibers.

Adult↗
PubMed1998

Abeta-fiber mediated activation of cingulate cortex as correlate of central post-stroke pain.

A patient is presented who suffered a lateral brainstem infarction which selectively abolished pain and temperature sensitivity in the lower right limb. One year later central post-stroke pain had developed in the affected limb with touch and cold allodynia. P40m dipoles calculated from magnetoencephalographic fields after electrical stimulation of both tibial nerves were localized in SI as is seen in normal subjects. However, stimulation of the affected side caused deep pain sensations and elicited a large N80m component, best explained by an additionally active dipole in cingulate cortex. This early co-activation in a limbic structure suggests peripheral Abeta-fiber mediation and lemniscal projection. Abnormal link to the pain system may be due to sensitization and reorganization above the level of nociceptive deafferentation.

Brain Stem↗
PubMed1998

Differentiation of conversive sensory loss and malingering by P300 in a modified oddball task.

We applied the methodology of evoked potentials (EP) to reveal the functional level of abnormality in a patient with circumscribed complete anaesthesia due to conversion disorder. EP components related to sensory and perceptual processing of both innocuous electrical and noxious laser stimuli were normal. However, a P300 component indicating cognitive processing failed to appear when using a modified oddball task with rare stimuli applied to the anaesthetic right hand. P300 was present with this paradigm stimulating the healthy left hand, as well as in a 'malingerer' - a healthy subject who was instructed to feign the same deficit. These results suggest cognitive deficits underlying sensory loss as conversion symptom which can be differentiated from malingering by use of P300.

Adult↗
PubMed1998

Tissue concentrations of nerve growth factor in aging rat heart and skeletal muscle.

In order to examine the association between adult nerve growth factor (NGF) levels and age-related changes in skeletal and heart muscle mass, we determined NGF concentrations in both tissues. NGF concentrations in rat heart muscle were significantly higher than those in skeletal muscle. NGF concentrations in heart muscle had a significant positive correlation with heart muscle wet weight. A causal association may exist between age-related changes in adult heart muscle mass and tissue NGF levels (in contrast to skeletal muscle). Among the potential clinical implications for skeletal muscle, it appears that age-related delay or deterioration in regeneration processes in neuromuscular diseases, or age-related decline in skeletal muscle mass, are not caused by reduced tissue NGF concentrations.

Aging↗
PubMed1998

[Epidemiologic data of stroke. Data of the WHO-MONICA Project in Germany].

Analyses of stroke morbidity or mortality are usually based on official statistics. A reduction in stroke mortality rates has been shown for many countries. It is not clear, however, whether this is due to declining morbidity or case fatality (or both). For this purposes population-based register data are required. Using the standardized methodology of the WHO-MONICA Project, stroke cases were also registered in Germany from 1984 to 1993 (7,435 first-ever and recurrent stroke cases). The data collection was almost restricted to East Germany. The age-specific stroke rates in males/females showed an increase from 9/11 per 100,000 population in the youngest age group (25-34) to 1,005/779 cases per year in the oldest group under study (65-74). If one tries to classify stroke types, which is not always possible in a population-based register, the best estimate for men (women) would be: 63(62%) thromboembolic stroke, 25(22)% intracerebral hemorrhage, and 12(17)% subarachnoid hemorrhage. The 28-day case fatality of the 25-74 year old stroke patients was found to be about 40%. Neither for stroke attacks nor for case fatality was a convincing time trend over the 10-year period found. The very small changes observed over 10 years time should lead to increased attention to strokes, particularly primary and secondary prevention, and this not only in East Germany. This applies also for treatment in the acute phase, because the case fatality before admission in the hospital and during the first few days is still very high. Population-based studies of the long-term prognosis of stroke patients in Germany are also missing, i.e., including the effectiveness of various forms of treatment and rehabilitation. Systematic monitoring of the development in this field is an important part of the assessment of the quality and effectiveness of the health care service.

Adult↗
PubMed1998

Tissue nerve growth factor concentrations in neuromuscular diseases.

In order to investigate the possible influences of pathological processes on muscle NGF levels in human subjects, we measured the NGF concentrations in muscle biopsies from 35 male and 16 female subjects (controls, n = 14; amyotrophic lateral sclerosis, n = 20; inflammatory myopathy, n = 6; muscular dystrophy, n = 11). The NGF concentration in each group was as follows: controls, 1.73 +/- 0.3 pg/mg protein (mean +/- S.E.M.); muscular dystrophies, 1.73 +/- 0.48 pg/mg protein; inflammatory myopathies, 2.28 +/- 1.45 pg/mg protein; amyotrophic lateral sclerosis, 4.15 +/- 0.79 pg/mg protein. The tissue NGF concentrations were significantly (140%) higher in patients with ALS than in the control subjects (P < 0.05, Wilcoxon signed rank test). Age and gender had no influence on tissue NGF concentrations. We conclude that the NGF increases observed here in affected muscle in amyotrophic lateral sclerosis can best be explained in terms of rapidly progressing denervation processes. Copyright 1998 Lippincott Williams & Wilkins

Journal Article↗
PubMed1998

Clinical changes and EEG patterns preceding the onset of periodic sharp wave complexes in Creutzfeldt-Jakob disease.

The conversion of EEG findings and the evolution of clinical signs was investigated in 7 CJD patients who underwent serial EEG recordings along the course. At the onset of PSWC (mean 8.7 weeks), 5 patients had already progressed to akinetic mutism (characterized by loss of verbal contact and directed responses); and a CJD-typical-movement disorder (myoclonia, exaggerated startle reaction or focal dyskinesia) had started in 5 patients. When akinetic mutism commenced (on average at 7.5 weeks), runs of frontal intermittent non-peaked rhythmical delta activity (FIRDA) were found in all cases. These were later replaced by PSWC in 6 patients (interval 1 to 3 weeks). Occurrence of PSWC was often negatively related to external stimuli (2 of 6 cases), and sedative medication (all patients tested). We conclude that the selection of EEG recording dates to detect PSWC in CJD-candidates should be guided by detailed information about movement disorders and conscious level. Regarding the short survival time after their onset (average 8 weeks), PSWC usually mark the terminal stage of CJD. To detect PSWC, especially, EEG registrations in advanced stages are often necessary. In earlier disease stages, FIRDA-like EEG activities should be regarded as compatible with this diagnosis, and encourage further EEG studies for the demonstration of PSWC in a more advanced stage of CJD.

Aged↗
PubMed1997

Prominent sensory ataxia in Guillain-Barré syndrome associated with IgG anti-GD1b antibody.

Sensitization with GD1b has been shown to cause sensory neuropathy in rabbit. A patient with chronic sensory-dominant polyneuropathy who had IgM antibody specifically to GD1b has been reported previously. This report describes the first patient with acute demyelinating polyneuropathy with prominent sensory symptoms who had a high titer of serum IgG anti-GD1b antibody. The serum reacted with neither GM1 nor with other b-series gangliosides (GD2, GD3, GT1b and GQ1b). Improvement in symptoms was coincident with decrease in IgG anti-GD1b antibody titer after plasmapheresis. This case supports the experimental results in rabbit suggesting that anti-GD1b antibody functions in the development of sensory ataxia.

Ataxia↗
PubMed1997

Effect of age on synthesis of the GABAergic steroids 5-alpha-pregnane-3,20-dione and 5-alpha-pregnane-3-alpha-ol-20-one in rat cortex in vitro.

Progesterone 5-alpha-reductase activity and 3-alpha-hydroxysteroid dehydrogenase activity were determined in the cortex of male and female rats in vitro. Age effects were investigated. The age of the male rats was 3-23 months, and that of the female rats 4-23 months. On addition, we investigated the enzyme 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase in rat cortex in order to estimate the local synthesis of progesterone from pregnenolone. We found age-related increases in progesterone 5-alpha-reductase activity in the female rats (r = 0.64, p < 0.01, n = 6) and in the male rats (r = 0.5, p < 0.05, n = 18). 3-alpha-HSDH activity remained constant with age in female and male rats. The ratio of 3-alpha-hydroxysteroid dehydrogenase activity to 5-alpha-reductase activity tended to decrease with age (not significantly) in both male rats (r = -0.45, p = 0.06, n = 19) and the female rats (r = -0.36, p = 0.17, n = 16). We could not detect significant metabolism of pregnenolone to progesterone in rat cortex in vitro. The sensitivity of the assays of 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase was calculated from the mean of the blank values + 3SD; the sensitivity of the assay was calculated as 0.103 fmol/mg protein/min. No significant metabolism of pregnenolone could be detected in cortex pooled from several male rats. The mean metabolism of progesterone was 1,200 times higher than the detection threshold of the assay for 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase. We conclude that modifications of the inhibitory effects of the GABAergic steroids 5-alpha-pregnane-3,20-dione and 5-alpha-pregnane-3-alpha-ol-20-one via altered progesterone metabolism in rat cortex are possible with aging. A connection with the age-related increase in incidence of epileptic attacks, and with age-related changes in the effects of anticonvulsant and GABAA-active drugs, appears possible.

3-Hydroxysteroid Dehydrogenases↗
PubMed1997

[Type I Charcot-Marie-Tooth syndrome. Disability and management].

Molecular genetic research on Charcot-Marie-Tooth 1 syndrome (CMT 1) progresses rapidly, still obviously no cure is available for affected individuals. Our aim was to investigate current management in clinical CMT 1 50 patients with Charcot-Marie-Tooth syndrome type I (CMT 1) were explored for applied means of therapy and use of health care institutions. We documented the number of annual appointments at a neurologist, orthopaedist and psychologist. Previous admissions to hospitals and rehabilitation centres and surgical procedures were assessed. Practice of physiotherapy, occupational and physical therapy were investigated, also administered orthopaedic devices, mechanical devices and technical modification of car and home. Drugs prescribed were listed and the number of patients seeking advice at para-medical institutions was determined. Degree of medical support did not correlate with severity of disease. We observed that persons with marked disability did not uniformly receive adequate therapy. This was partly due to the responsible physicians, and partly due to lacking cooperation of the patients. Support of affected individuals and counselling to our opinion are to be improved. This would require further evaluation of therapies, establishment and distribution of guidelines, as well as motivation of patients, which might be facilitated by the offer of molecular genetic diagnostics.

Adolescent↗