PubMed Health⌕ Search

Biomedical subjects

L Vogt

Publications and source records attributed to L Vogt.

At least 19 recordsLinked to original sources
PubMed2002

Comparison of angular lumbar spine and pelvis kinematics during treadmill and overground locomotion.

OBJECTIVE: To determine the differences between angular oscillation curves of the lumbar spine and pelvis during walkway and treadmill ambulation. DESIGN: An in vivo observation of walking in overground and treadmill conditions. BACKGROUND: Angular movements of the lumbar spine and pelvis have been obtained during overground and treadmill walking. No data are available to indicate whether lumbar spine treadmill findings may be compared or generalized to overground readings. METHODS: Nine male subjects walked at their natural cadence along an 8 m walkway positioned over a motorized treadmill. During each of 20 walking trials, kinematic data of one full gait cycle were collected in the middle segment of the walkway. Following the overground readings the walkway was removed and treadmill recordings were taken at the subjects' preferred walking speed and at an imposed speed of 1.25 m/s. Movement patterns and maximum oscillation angles were calculated in each plane. RESULTS: Cross-correlation values of pairwise comparisons demonstrated almost comparable movement patterns between walking conditions (r > or =0.891; p<0.001) except for the movement in the sagittal plane (r=0.642, p<0.01). ANOVA for repeated measures revealed significant (p<0.05) differences in the gait cycle duration as well as reductions in oscillation amplitudes of the upper lumbar region and the pelvis in both the frontal and transverse plane during treadmill walking compared to walkway locomotion. CONCLUSIONS: Statistically significant differences exist for some angular lumbar spine movement parameters between walkway and treadmill locomotion. RELEVANCE: The observed differences between overground and treadmill locomotion should be taken in account when treadmill-based lumbar spine and pelvis kinematics want to be extended or compared to overground recordings.

Adult↗
PubMed2001

Influences of nonspecific low back pain on three-dimensional lumbar spine kinematics in locomotion.

STUDY DESIGN: A three-dimensional kinematic analysis of lumbar spinal movements with an ultrasonic measuring system was used to distinguish patients with chronic low back pain from those without such pain. OBJECTIVES: To investigate the effects of chronic low back pain on the three-dimensional movements of the lumbar spine, and to identify variables that would allow discrimination among patients with chronic low back pain and control subjects. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, no previous studies have described or identified altered spinal and pelvic gait kinematics caused by nonspecific chronic low back pain in all anatomic planes. METHODS: In this study, 34 participants with chronic low back pain and 22 subjects without such pain were monitored during treadmill gait. Data from the measuring system operating at 30 Hz were low-pass filtered and normalized to a percentage of the gait cycle. RESULTS: Cross-correlations showed almost identical patterns of pelvic (S1) and thoracic (T12) movement curves in all anatomic planes between groups. No statistical group differences were detected for either pelvic or thoracic oscillation amplitudes. However, Student's t test showed significantly higher coefficients of variation (P < 0.01) in all anatomic planes of patients with chronic low back pain than in healthy control patients. CONCLUSIONS: The phasic patterns and angular spinal displacements of patients with nonspecific low back pain were shown to be within normal limits. However, the patients demonstrated higher degrees of stride-to-stride variability, representing increased fluctuations in dynamic thoracic and pelvic oscillations. These findings, resulting in less than optimal gait patterns, must be considered in the rehabilitation of patients with chronic low back pain.

Adult↗
PubMed2001

Sorting and directed transport of membrane proteins during development of hippocampal neurons in culture.

Hippocampal neurons in culture develop morphological polarity in a sequential pattern; axons form before dendrites. Molecular differences, particularly those of membrane proteins, underlie the functional polarity of these domains, yet little is known about the temporal relationship between membrane protein polarization and morphological polarization. We took advantage of viral expression systems to determine when during development the polarization of membrane proteins arises. All markers were unpolarized in neurons before axonogenesis. In neurons with a morphologically distinguishable axon, even on the first day in culture, both axonal and dendritic proteins were polarized. The degree of polarization at these early stages was somewhat less than in mature cells and varied from cell to cell. The cellular mechanism responsible for the polarization of the dendritic marker protein transferrin receptor (TfR) in mature cells centers on directed transport to the dendritic domain. To examine the relationship between cell surface polarization and transport, we assessed the selectivity of transport by live cell imaging. TfR-green fluorescent protein-containing vesicles were already preferentially transported into dendrites at 2 days, the earliest time point we could measure. The selectivity of transport also varied somewhat among cells, and the amount of TfR-green fluorescent protein fluorescence on intracellular structures within the axon correlated with the amount of cell surface expression. This observation implies that selective microtubule-based transport is the primary mechanism that underlies the polarization of TfR on the cell surface. By 5 days in culture, the extent of polarization on the cell surface and the selectivity of transport reached mature levels.

Animals↗
PubMed2001

The application of fetal magnetocardiography (FMCG) to investigate fetal arrhythmias and congenital heart defects (CHD).

OBJECTIVES: Fetal magnetocardiography (FMCG), a new non-invasive diagnostic tool in the analysis of the electrophysiological changes of the heart, was selectively applied in cases of fetal arrhythmias and congenital heart defect (CHD) to demonstrate its value for diagnosis and prenatal management. METHODS: The FMCG was analysed and compared to the postnatal ECG in four cases of fetal arrhythmia [supraventricular tachycardia (two cases), complex tachy-/bradycardia (one case), ventricular extrasystoles (one case)] and a case of right heart hypoplasia diagnosed by established methods prior to investigation. RESULTS: A Wolf-Parkinson-White (WPW) syndrome was diagnosed by its characteristic features and the appropriate transplacental therapy chosen. The types of arrhythmia could be characterised in accordance with postnatal ECG findings and irregular conduction was demonstrated in association with a CHD. CONCLUSIONS: The use of the FMCG provides additional information to the common diagnostic tools that influence therapeutic decisions and thus contributes to optimal pre- and postnatal management.

Adult↗
PubMed2001

Calsyntenin-1, a proteolytically processed postsynaptic membrane protein with a cytoplasmic calcium-binding domain.

In a screen for proteins released from synapse-forming spinal cord neurons, we found the proteolytically cleaved N-terminal fragment of a transmembrane protein localized in the postsynaptic membrane of both excitatory and inhibitory synapses. We termed this protein calsyntenin-1, because it binds synaptic Ca2+ with its cytoplasmic domain. By binding Ca2+, calsyntenin-1 may modulate Ca2+-mediated postsynaptic signals. Proteolytic cleavage of calsyntenin-1 in its extracellular moiety generates a transmembrane stump that is internalized and accumulated in the spine apparatus of spine synapses. Therefore, the synaptic Ca2+ modulation by calsyntenin-1 may be subject to regulation by extracellular proteolysis in the synaptic cleft. Thus, calsyntenin-1 may link extracellular proteolysis in the synaptic cleft and postsynaptic Ca2+ signaling.

Animals↗
PubMed2001

[Inline skating in school--perspectives from the sports medicine viewpoint].

INTRODUCTION: Children are motivated by new activities in physical education. Inline Skating (ILS) is one of the trend activities of the last years. For the establishment of ILS in school injury risks and the possible preventive transfer in leisure time activities are of interest. The aim of this study was to compare the incidence of injuries in an ILS-program in school with traditional activities of exercise lessons. Furthermore inline skate specific injury incidence in leisure time was evaluated. METHOD: A sample of 47 schools was evaluated by a standardized questionnaire asking for: injury incidence in traditional sports and ILS and the incidence of ILS-injuries in leisure time. RESULTS: The relative injury risk of ILS (% per 100 teaching units) is 14.3%. Basketball e.g. has an injury risk of 16.1%, handball 14.6%, gymnastics 13.9% and other games 9.5%. After the end of the ILS-program 37.3% of the students reported the incidence of an injury due to ILS in leisure time. CONCLUSION: Compared to other activities in physical education ILS shows a moderate risk of injury and may improve the acceptance of active and passive prophylaxis.

Adolescent↗
PubMed2000

Efficient translation of mouse hypoxia-inducible factor-1alpha under normoxic and hypoxic conditions.

The heterodimeric hypoxia-inducible factor-1 (HIF-1), consisting of the subunits HIF-1alpha and HIF-1beta/ARNT, is a master transcriptional regulator of oxygen homeostasis. Under hypoxic conditions, HIF-1alpha levels very rapidly increase, mostly due to protein stabilization. However, translational regulation of HIF-1alpha has not been directly analyzed so far. Mouse HIF-1alpha exists as two mRNA isoforms (termed mHIF-1alphaI.1 and mHIF-1alphaI. 2) containing structurally different 5'-termini which might modulate translation initiation. Whereas the in vitro translation efficiency of these two mRNA isoforms was about equal, the mHIF-1alphaI.2 5'-untranslated region (5'-UTR) conferred significantly higher in vivo luciferase reporter gene activity than the mHIF-1alphaI.1 5'-UTR. Similar corresponding luciferase mRNA levels indicate translational rather than transcriptional alterations. Reporter gene expression was not affected upon exposure of transiently transfected cells to hypoxia (1% oxygen). Direct assessment of translational regulation by polysomal profile analysis of HeLaS3 cells showed that HIF-1alpha (and to a lower extent ARNT) mRNA was found mainly in the translationally active polyribosomal fractions under both normoxic and hypoxic conditions. In contrast, the association of mRNAs for beta-actin and ribosomal protein L28 with the polyribosomal fractions was substantially reduced under hypoxic conditions, suggesting decreased overall protein synthesis. Thus, efficient translation of mouse HIF-1alpha in a situation where the general translation efficiency is reduced represents a prerequisite for the very rapid accumulation of HIF-1alpha protein upon exposure to hypoxia.

Animals↗
PubMed2000

[Reproducibility of lumbar spine kinematics in clinical gait analysis].

The objective measurement of functional lumbopelvical movements enables the evaluation of the quantity and quality of movements referring to functional disorders in dynamic test-situations. The goal of the present study is the determination of the reproducibility of time-continuous movement analysis of the pelvic region during walking and the determination of possible errors. The movements of the thoracic (Th12), lumbar and sacrum-region (S1) of 17 healthy subjects (age: 32.1 +/- 2.3 years) during walking on a treadmill (4.5 km/h) were investigated twice in an interval of 24 hours by means of a 3D ultrasonic movement analysis system. The ensemble averages of the low-pass filtered and time-normalized angle-time sequences of all anatomical planes and regions showed high test-retest correlations (r > or = 0.92, p < 0.01) except fo the lumbar movement in the sagittal plane (r = 0.79, p < 0.01). A paired t-test showed no significant differences for the amplitudes of test and retest measurements except for the thoracolumbar movement in the sagittal plane (p < .05). The results show that the evaluation of lumbar movement patterns can be regarded as admissible and desirable for clinical movement analysis. The data can be used as a diagnostic tool for the planning and control of therapeutic interventions.

Adult↗
PubMed1999

Neuronal depolarization enhances the transcription of the neuronal serine protease inhibitor neuroserpin.

Neuroserpin is an axonally secreted neuronal serine protease inhibitor. Based on its inhibitory activity towards tissue plasminogen activator (tPA) and its predominant expression in the cerebral cortex, the hippocampus, and the amygdala, a role for neuroserpin in the regulation of neural plasticity has been suggested. We recently found that neuroserpin mRNA is increased in cultured hippocampal neurons upon depolarization with elevated extracellular KCl. Using luciferase reporter constructs containing segments of the promoter region of the neuroserpin gene, we identified a 200-bp segment near the transcription initiation site that is responsible for both the neuron-specific expression of the neuroserpin gene and the enhanced transcription resulting from depolarization. Nerve growth factor, which alone had no effect on the expression of neuroserpin mRNA in hippocampal neurons, had a marked potentiating effect when supplied in combination with elevated extracellular KCl. In contrast, the transcription factor zif/268 blocked neuroserpin transcription. These results implicate neuroserpin as an activity-regulated modulator of tPA activity at the synapse and provide further support for the occurrence of activity-regulated proteolytic processes at the synapse.

Animals↗
PubMed1999

Vascular complications (splenic and hepatic artery aneurysms) in the occipital horn syndrome: report of a patient and review of the literature.

We report an 18-year-old boy with occipital horn syndrome who developed aneurysms of the splenic and hepatic arteries. Occipital horn syndrome, also called X-linked cutis laxa or Ehlers-Danlos syndrome (EDS) type IX, is characterised by a skeletal dysplasia which includes occipital horns, broad clavicles, deformed radii, ulnae and humeri, narrow rib cage, undercalcified long bones and coxa valga. Distinctive features common to all patients are unusual facial appearance, hypermobility of finger joints, limitation of extension of elbows, chronic diarrhoea and genitourinary abnormalities. In this case report we describe the difficulties encountered in the diagnostic management of patients with EDS-related vascular lesions.

Adolescent↗
PubMed1999

Measurement of lumbar spine kinematics in incline treadmill walking.

A study was undertaken to analyse and compare the pelvic (S1) and the trunk (T12) oscillations during level and uphill walking and to provide kinematic baseline data of the lumbar region in incline walking for future comparisons with pathological gait patterns. An ultrasonic movement analysis device (Zebris(R) CMS 50) was used to obtain three-dimensional kinematic data for the pelvis and thorax. Data from treadmill walking at 0 and 10% incline of 22 adults were used for within subject analysis. Crosscorrelation values ranged from r=0.76 to 0.98 (P<0.001) demonstrating a strong degree of agreement between the temporal patterns of angular displacement of the trunk and pelvis in the sagittal, transverse and frontal plane in incline compared to level ambulation. However, Student's t-tests revealed significantly (P<0.01) higher amplitudes for thorax displacements in the frontal and transverse plane in uphill walking. No significant differences were detected for amplitude parameters of the pelvis. It could be stated that the phasic patterns in level walking are not different from that obtained for incline walking. It is concluded that incline ambulation exerts the major influences in the thoracic region by increasing amplitudes of axial rotations.

Adult↗
PubMed1998

Neurite fasciculation mediated by complexes of axonin-1 and Ng cell adhesion molecule.

Neural cell adhesion molecules composed of immunoglobulin and fibronectin type III-like domains have been implicated in cell adhesion, neurite outgrowth, and fasciculation. Axonin-1 and Ng cell adhesion molecule (NgCAM), two molecules with predominantly axonal expression exhibit homophilic interactions across the extracellular space (axonin- 1/axonin-1 and NgCAM/NgCAM) and a heterophilic interaction (axonin-1-NgCAM) that occurs exclusively in the plane of the same membrane (cis-interaction). Using domain deletion mutants we localized the NgCAM homophilic binding in the Ig domains 1-4 whereas heterophilic binding to axonin-1 was localized in the Ig domains 2-4 and the third FnIII domain. The NgCAM-NgCAM interaction could be established simultaneously with the axonin-1-NgCAM interaction. In contrast, the axonin-1-NgCAM interaction excluded axonin-1/axonin-1 binding. These results and the examination of the coclustering of axonin-1 and NgCAM at cell contacts, suggest that intercellular contact is mediated by a symmetric axonin-12/NgCAM2 tetramer, in which homophilic NgCAM binding across the extracellular space occurs simultaneously with a cis-heterophilic interaction of axonin-1 and NgCAM. The enhanced neurite fasciculation after overexpression of NgCAM by adenoviral vectors indicates that NgCAM is the limiting component for the formation of the axonin-12/NgCAM2 complexes and, thus, neurite fasciculation in DRG neurons.

Animals↗
PubMed1998

Lack of evidence of kappa2-selective activation of G-proteins: kappa opioid receptor stimulation of [35S] GTPgammaS binding in guinea pig brain.

Although only one gene for kappa opioid receptors has been cloned to date, kappa1 and kappa2 receptors have been defined pharmacologically, with drugs such as bremazocine binding to both putative kappa receptor subtypes. To examine whether kappa receptor subtypes can be distinguished at the level of the G-protein, the ability of the kappa1 agonist (trans-(dl)-3,4-dichloro-N- methyl-N-[2-(1 -pyrrolidinyl)cyclohexyl]-benzeneacetamide) methane sulfonate (U-50488H) to stimulate [35S]guanosine-5'-O-(gamma-thio)-triphosphate ([35S]GTPgammaS) binding in guinea pig brain was compared with that of bremazocine and dynorphin. In membranes prepared from guinea pig striatum, both bremazocine and U-50488H stimulated [35S]GTPgammaS binding with the same relative efficacy, while dynorphin produced at least two-fold greater efficacy than the other two agonists. In vitro autoradiography of agonist-stimulated [35S]GTPgammaS binding revealed similar regional distributions of bremazocine- and U-50488H-activated G-proteins. In striatal membranes, the kappa antagonist nor-binaltorphimine (nor-BNI) blocked both bremazocine- and U-50488H-stimulated [35S]GTPgammaS binding with similar Ke values. In agonist additivity experiments, the stimulation of [35S]GTPgammaS binding by the delta agonist [D-pen2'5, p-Cl-Phe4]enkephalin (p-Cl-DPDPE) was approximately additive with the two kappa agonists. Stimulation of [35S]GTPgammaS binding by the mu agonist [D-Ala2, N-Me4, Gly5-ol]-enkephalin (DAMGO) was additive with U-50488H, but not with bremazocine, reflecting the mu antagonist properties of this compound. The combination of bremazocine and U-50488H together produced no greater stimulation of binding than either agonist alone, indicating that they were binding to the same site. These results demonstrate that bremazocine and U-50488H activate G-proteins in guinea pig brain through the same receptor, and suggest that kappa2 receptors are not coupled through the same signal transduction mechanisms as kappa1 receptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1997

Diabetes and hypertension in rodent models.

As shown by ourselves and others, animals models closely resembling human complex diseases like IDDM in BB/OK and hypertension in SHR/Mol rats can be used to dissect a complex disease into discrete genetic factors as has been done for hypertension in (BB/OK x SHR/Mol) cross hybrids. Discrete genetic factors, so-called QTLs, were detected on chromosomes 1, 10, 18, 20, and X. To gain additional information about the physiologic effect of the mapped blood pressure QTLs, genetically defined regions of the SHR rat were transferred onto the genetic background of diabetes-prone BB/OK rats. Four new congenic BB.SHR rats named BB.Sa, BB.Bp2, BB.1K, and BB.Xs were generated and characterized telemetrically for blood pressure, heart rate, and motor activity. The data demonstrate clearly that each single blood pressure QTL of the SHR rat causes a significant increase of the systolic blood pressure and has a different influence on diastolic blood pressure, heart rate, and motor activity. The effects were modified differently by the diabetic state in BB.Sa, BB.Bp2, and BB.Xs rats carrying all diabetogenic genes of the BB/OK rats. The results demonstrate that these newly established congenic strains are a unique tool to study the physiological control of blood pressure by a single blood pressure QTL on the one hand and their interaction with hyperglycemia on the other. It is well within the bounds of possibility that diabetic congenics reflect the diabetic hypertension seen in diabetic patients. Because of the synteny conservation in gene order between different mammals, genes of the appropriate human region could therefore be candidate genes for hypertension in diabetics. Furthermore, these congenic strains can also be used to study interactions between a blood pressure QTL and various selected environmental conditions. In this way, one could learn which QTL can be influenced by environmental factors and to what extent. Another point is the study of gene interactions. Because congenics are genetically identical except for the defined transferred region, congenics can be crossed to investigate the interaction between two or three blood pressure QTLs selected by the investigator and not by nature. These QTL combinations can be studied in the nondiabetic as well as diabetic state. Although the advantage of congenic strains has been shown, the transferred chromosomal regions are too large to pinpoint the gene responsible for the phenotypic change. Therefore, regions on each chromosome must be systematically whittled down, which can be done by crossing the congenics with BB/OK rats and intercrossing their progeny to generate recombinants. These can then be used for the creation of new congenic lines carrying a much smaller region of the SHR/Mol rat. This has been started for the region on chromosome 1 spanning a 16-cM region from the Sa to the Igf2 gene. BB.Sa rats were therefore backcrossed onto BB/OK rats and the resulting progeny were intercrossed. The aim will be to create at least three new congenic BB.Sa rat strains homozygous for the SHR alleles of Sa, Lsn, or Igf2 genes. However, new problems will emerge with these new congenics. To genetically define small regions requires more dense polymorphic markers than are currently available. Dense polymorphic markers will also be necessary to split the other regions on chromosomes 10, 18, 20, and X. We expect that in the near future it will be possible using this approach to define small regions of < 0.5 cM. The recent progress in gene mapping in the rat gives hope that the use of such congenic lines will allow the identification and recovery of the blood pressure genes in the near future.

Animals↗