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Biomedical subjects

H Ackermann

Publications and source records attributed to H Ackermann.

At least 109 records · Page 6Linked to original sources
PubMed1987

Changes in sensorimotor functions after spinal lesions evaluated in terms of long-latency reflexes.

Lesions of the central afferent and efferent pathways cause onset-delays of long-latency EMG responses from anterior tibial muscle after passive dorsiflection of the ankle joint in standing subjects. In 23 patients with spinal tumour or cervical stenosis and clinical signs of a medullary lesion, short-, medium- and long-latency EMG responses from distal leg muscles after ankle dorsiflection were recorded prior to and after surgical intervention. Fifteen of the patients were re-examined between 1 and 2 years after surgery. The results of the follow-up study support the hypothesis of a supraspinal pathway for long-latency EMG responses in distal leg muscles and show their significance as a quantitative measure of sensorimotor functions.

Electromyography↗
PubMed1986

Mechanically evoked cerebral potentials and long-latency muscle responses in the evaluation of afferent and efferent long-loop pathways in humans.

Standing humans were subjected to sudden tilts of a platform toe-up. This resulted in a long-latency response in the anterior tibial muscle with a mean latency of 132 ms. The same physiological stimulus was applied to evoke cerebral potentials. The mechanically evoked potential was characterized by a positive peak with a mean latency of 76.4 ms. Absolute peak latencies were variable between subjects but the side difference after separate stimulation of both legs was only around 2 ms. The recording of both, mechanically evoked long-latency muscle responses and cerebral potentials allows a separate evaluation to be made of afferent and efferent central pathways.

Adult↗
PubMed1986

[Function-oriented neurophysiologic diagnosis: long loop reflexes in spinal and cerebral lesions].

Neurophysiological methods which allow to identify objectively lesions of the efferent cortico-spinal pathways in humans are with the exception of transcutaneous electrical stimulation of the motor cortex nor available. Long latency EMG responses from leg muscles are mediated by a "transcortical loop" and offer the possibility to detect in combination with sensory evoked potentials lesions both of the afferent proprioceptive and the efferent motor pathways. Subjects stood on a platform which was rotated toe-up (50 degrees/s, 4 degrees) around the axis of the ankle joint. This lead to two EMG responses of short- and medium latency in the stretched triceps surae muscle, and an EMG response of long latency (LL) from the antagonistic anterior tibial muscle. We investigated 135 patients with a spinal or cerebral lesion, detected by neuroradiological methods. We found a significant delay of LL in patients with spinal lesions and in patients with cerebral lesions on the affected side. A significant delay of LL could also be observed in patients with pure motor symptoms and normal latency of the cerebral potential (P 40) alone in the group of patients with spinal lesions revealed in about 45% a pathological result. The rate of pathological findings was about 65% when both methods (SEP and LL) were combined. The results indicate that the recording of LL is helpful to detect lesions of the efferent central pathways. In a follow-up study we investigated patients who underwent successful surgical treatment. We found a close correlation between the decrease in latencies of LL and the improvement of clinical signs.

Adult↗
PubMed1985

Medium- and long-latency responses to displacements of the ankle joint in patients with spinal and central lesions.

In order to elucidate further the possible pathways and the functional significance of long-loop reflexes we recorded short-, medium- and long-latency responses from leg muscles in 27 patients with spinal lesions, 20 patients with central lesions of the internal capsule or cerebral hemisphere, and in 18 control patients with frontal or occipital lesions without motor or sensory disturbances. Our normal population included 50 subjects, who were age and sex matched to the patients. The mean latency of the long-latency response (LL) in the anterior tibial muscle was significantly delayed in patients with spinal (164.5 msec) and central lesions (145.1 msec) compared to control patients (123.5 msec) and the normals (125.3 msec). This delay of LL could be observed in patients who exhibited only motor or sensory disturbances or a combination of both. The medium-latency response (ML) was absent in 47% of the records in patients with spinal lesions, mainly on the side which was clinically more affected. Its latency was normal if the response occurred. The integral of the LL response was enlarged in patients with spinal or central lesions, but was also enlarged in the control group. The results indicate that the ML response is segmental, but that its amplitude is modulated by supraspinal structures. The LL response probably corresponds to a transcortical 'reflex.'

Ankle Joint↗
PubMed1981

[Effect of various xenobiotics on the in vivo incorporation of 14C-acetate into cholesterol and other lipids in the rat].

Effects of some xenobiotics on the incorporation in vivo of [14C]-acetate into cholesterol and other lipids of the rat DDT, HCH, polychlorinated biphenyl, chlorcholine chloride, ethylenthiourea and mixtures of these substances were given to rats with the feed for 7 days. After that the incorporation of [14C]-acetate into phospholipids, triglycerides and cholesterol was studied in liver, serum, heart and brain. The influence of the xenobiotics on the synthesis, transport and accumulation differed among the various organs and lipids. Outstanding was an increase of 14C-phospholipids, -triglycerides and -cholesterol in the heart after administration of polychlorinated biphenyl. The effects in the peripheral organs were generally more distinct than on the liver.

Acetates↗
PubMed1979

[Chromatographic behavior of phthalimide derivatives on silica gel layers].

The chromatographic behaviour of phthalimide derivatives during thin-layer chromatography on silica gel is explained by the repercussions of mesomeric and inductive effects on the specific combined action of the oxygen of the carbonyl groups and of protonized hydrogen atoms of the active centres on the surface of the adsorbent. It is shown that within the groups of solvents the products of the eluting power of the solvent by the activity of the adsorbent is proportional to the amount of the Rf value.

Chromatography, Thin Layer↗
PubMed1979

[Effect of the phosphonic acid derivatives ethephon and trichlorphon on the incorporation in vivo of (14C)-acetate into cholesterol and other lipids in rats].

The effect of the phosphonic acid derivatives Ethephon and Trichlorphon on the incorporation of 14C-labelled acetate into lipids especially cholesterol was investigated. Adult Wistar rats were fed for 7 days diets containing 50 and 500 ppm, respectively, of the phosphonic acid derivatives. Both compounds caused a significant increase of the 14C-activity in lipids of serum, liver, heart, and brain. The effect of Ethephon was significantly more intense than that of Trichlorphon. The important finding was the Ethephon-induced increase of the [14C]-acetate incorporation into cholesterol which continued across all the tissues studied.

Acetates↗
PubMed1978

Metabolic and toxic behaviours of phthalimide derivatives in albino rat II. Placental passage of chloromethyl phthalimide, oxymethyl phthalimide and phthalimide--their fetal metabolism.

Chloromethyl phthalimide, oxymethyl phthalimide, and phthalimide are absorbed by the albino rat at a comparatively high rate. Only phthalimide, the metabolic product, will be recordable from fetuses, following oral administration of chloromethyl phthalimide and oxymethyl phthalimide topregnant rats. Those findings, in conjunction with metabolic studies applied to fetuses isolated by caesarian section, appear to suggest the occurrence of an intensive metabolism in fetal tissue. Certain differences established between results of thin-layer chromatography, on the one hand, and 15N studies, on the other, are likely to support the assumption that phthalimide is further metabolised by splitting the imide ring yielding phthalamic acid.

Animals↗