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Biomedical subjects

J Adam

Publications and source records attributed to J Adam.

At least 91 records · Page 5Linked to original sources

The effect of posterior column lesions on servo responses from the human long thumb flexor.

Lesions of the posterior column pathways, in which muscle spindle afferents run towards the brain, are associated with loss of servo responses in the long flexor of the thumb, in the absence of motor weakness and with tendon jerks preserved. This evidence is consistent with the hypothesis that the long-latency stretch reflex (on which servo responses are based) uses a supraspinal, possibly a transcortical, reflex arc.

Adult↗

The effect of lesions of the sensorimotor cortex and the capsular pathways on servo responses from the human long thumb flexor.

Lesions of the sensorimotor cortex, or of the capsular pathways beneath it, caused (with one exception out of 14 cases) diminution "r loss of the servo responses in the thumb, which are based on the long-latency stretch reflex. When not absent the long-latency stretch reflex tended to be late in onset. When absent it was often replaced by a large early reflex response at spinal latency. In general the results are consistent with the transcortical theory of the long-latency stretch reflex for the thumb, but, in detail, they indicate that the theory will require elaboration.

Adult↗

Reticular reflex myoclonus: a physiological type of human post-hypoxic myoclonus.

A patient with post-hypoxic myoclonus, sensitive to therapy with 5-hydroxytryptophan and clonazepam, was subjected to detailed electrophysiological investigation. Brief generalised jerks followed the critical stimulus of muscle stretch. The electroencephalogram showed generalised spikes that were associated with, but not time locked to, the myoclonus. The cranial nerve nuclei were activated upward. Analysis of the findings suggests that the mechanism of the myoclonus is hyperactivity of a reflex mediated in the reticular formation of the medulla oblongata.

5-Hydroxytryptophan↗

[Effect of chlortetracycline on the peptide spectrum of rat serum].

Application of chlortetracycline in rats resulted in the occurence of certain peptides in the blood-serum, which could not be detected in the serum of an untreated control group. These results were obtained by means of high voltage electrophoresis and paper electrophoresis of the serum of rats which was analyzed 1,3, and 13 hours respectively after a single dose of 50 mg chlortetracycline per 100 g body weight in comparison to an untreated control group. The new peptides could be found in the slight alkaline range 1 and 3 hours after application of chlortetracycline and in the strong acidic area of the electrochromatogram 13 hours thereafter. A more detailed investigation of the new peptides could demonstrate that the number of the following amino acids was reduced in the peptide chains after chlortetracycline: leucine, valine, serine, arginine, and lysine. On the other hand, amino acids, such as citrulline, sarcosine, alpha-aminobutyric acid, and ornithine, could be found which are normally not present in proteins.

Amino Acids↗

[Effect of the prolonged administration of chlortetracycline on the content of free amino acids and low-molecular peptides in the blood serum of rats].

Five individual ninhydrin positive fractions were found in the blood serum of rats in the control group with the help of high voltage electrophoresis in combination with preparative high voltage electrophoresis and paper chromatography. An analogous analysis of the blood serum of the test animals treated with 50 mg/kg of chlortetracycline for 12 days revealed 1 new fraction in the weak basic region. After the use of chlortetracycline for 18 days 2 new fractions in the strong acid region, 1 new fraction at the level of the electrophoretic mobility of asparaginic acid and 2 fractions in the region between neutral and basic amino acids were found. Analysis of the above fractions showed that the blood sera of the control and test rats contained in addition to the free amino acids peptides consisting of 3 to 9 amino acid residues. Some peptides isolated from the sera of the test animals contained amino acids, such as ornithine and citrulline which are not usually contained in proteins.

Administration, Oral↗