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Biomedical subjects

H C Hopf

Publications and source records attributed to H C Hopf.

At least 163 records · Page 9Linked to original sources
PubMed1980

Intermittent Horner's syndrome on alternate sides: a hint for locating spinal lesions.

A patient with a cervical intramedullary ependymoma is described who exhibited a Horner's syndrome on alternate sides. Pharmacological study demonstrated damage to the pre-ganglionic sympathetic neurons. Disregarding cases with the Shy-Drager syndrome, three comparable case reports have been found in the literature where the fluctuating expression of Horner's syndrome, alternating from one side to the other, was attributable to a lesion of the cervical spinal cord. In contrast to the present patient, the pharmacological responses of these patients indicated a lesion of the central sympathetic pathway.

Adult↗
PubMed1979

[Early auditory evoked potentials, triggered by a sine-wave stimulus (author's transl)].

Within the first 10 ms after a sine-shaped sound wave (tone pip) seven small-amplitude potentials can be recorded in persons with normal hearing and normal brainstem functions. These components, in the nanovolt range, correspond to the electrical activity of various pathways of the auditory tract. In accordance with this view the resulting potentials were assigned to the following structures in the region of the periphery and the brainstem: component I corresponds to the cochlea or acoustic nerve (receptor, II to the cochlear nucleus (medulla), III to the upper olive (caudal pons), IV to the lateral lemniscus (rostral pons), V to the inferior colliculus (midbrain), VI to the medial geniculate body (diencephalon), VII to the acoustic radiation (cortex). Clinically well defined lesions of the acoustic nerve and brainstem indicate that there is a close topographical relationship between the clinical localisation and absence or delay of the individual components.

Auditory Pathways↗
PubMed1979

[Basic conditions for electromyographic examination. Part I: EMG, nerve conduction velocity and test of motor end-plate function (author's transl)].

The purpose of the following contribution is to give a survey about the basic conditions of electromyographic examination. The necessary apparatus will be described as well as the course of examination. Moreover the parameter for the evaluation will be explained together with exogenous falsifying influences. This contribution is thought to be a guide for orientation to improve electromyographic recording and evaluation.

Electric Stimulation↗
PubMed1978

Impaired refractory periods of peripheral sensory nerves in multiple sclerosis.

Maximum conduction velocity and relative refractory period (RRP) of median nerve sensory fibers were studied in 36 patients diagnosed as having multiple sclerosis (MS) and in 31 controls. Maximum conduction velocity did not differ in the two groups, but the RRP was significantly prolonged in MS patients. Increased RRP is observed mainly when peripheral nerve myelin is abnormal or damaged. Our findings support the assumption that peripheral nerve myelinated fibers are usually involved in MS.

Adult↗
PubMed1977

Changes of sensory conduction velocity and refractory periods with decreasing tissue temperature in man.

Changes with temperature of maximum sensory nerve conduction velocity as well as absolute and relative refractory periods were tested in 14 human subjects. Corresponding to previously published findings maximum conduction velocity decreased with cooling following a Q10 of +1.4. The absolute and relative refractory periods were increased by cooling, the Q10 being -3.1 and -3.35 respectively. There was a tendency showing a more pronounced temperature effect at low temperatures. The Q10 and the steepness of the regressionline changed at the level of 26.9 degrees C, but were significant for the relative refractory period only.

Action Potentials↗
PubMed1977

Hypokalemia shortens relative refractory period of peripheral sensory nerves in man.

Absolute and relative refractory periods and the sensory conduction velocity of the median and ulnar nerves were determined in six patients suffering from hypokalemia of various origins. Nerve impulse conduction and the absolute refractory period remained normal, but the relative refractory period was shortened to 1.7 to 2.6 ms at serum K+ levels from 1.6 to 2.9 mval/l. As compared with normal values this decrease was statistically significant.

Humans↗
PubMed1977

[Electromyography as a diagnostic aid (author's transl)].

Electromyography reflects the anatomical situation in the muscle parenchyma. Changes in the anatomical structure are present if the normal potential form breaks up into small amplitude or even polyphasic potentials (myopathy type) or increases into high amplitude, broad and coarsely fragmented potentials (chronic neuropathy with regeneration). The caliber and type of muscle fibers are expressed in the speed of conduction. Spontaneous activity suggests an increased excitability of the muscel fibers. Disturbances of neuromuscular transmission are detectable by direct stimulation of the muscle. Analysis of nerve conductivity permits the demonstration of diffuse (polyneuropathy type) or circumscribed (entrapment neuropathy type) nerve affections. The recording of the parameters mentioned is the domain of EMG.

Electromyography↗
PubMed1977

Adult metachromatic leukodystrophy. I. Clinical manifestation in a female aged 44 years, previously diagnosed in the preclinical state.

In a 5-year follow-up of a case of adult metachromatic leukodystrophy, already diagnosed in the preclinical stage, the development of the symptoms of this disease could be studied in detail: initially, lack of drive, emotional lability and depressive mood. At the same time, pain in the arms and beginning gait disturbance. Later, impairment of memory and concentration, disorientation, inadequate behavior and progression of gait disturbance. Finally spastic atactic gait with small steps and dyspractic components, coordination disturbances with writing dysfunction, fast dysarthric speech, hyperkinetic activity, compulsory emotional outbursts and progressive dementia. Only minor neurological signs such as reflex abnormalities. In the EEG, slight slowing of frequencies compared to earlier tracings. Increasing diminution of nerve conduction velocity in the lower limbs. Only minor increase of CSF protein (51 mg%). In spite of normal vision, evoked visual potentials abnormal, response of optical and electrical blink reflexes delayed. Imperfect filling of gallbladder. No significant quantitative changes of the biochemical parameters compared with the findings made 5 years earlier (excretion of urinary sulfatides, diminished activity of arylfulfatase A in urine and leukocytes).

Adult↗
PubMed1976

[Penicillamine-induced myasthenia in chronic rheumatoid arthritis (author's transl)].

A myasthenic reaction developed after an average latency of seven to eight months in 12 female patients (average age 51 years) treated with penicillamine for chronic rheumatoid arthritis. In most of them only the purely ocular form was noted, but generalisation of various degrees also occurred. When penicillamine had been discontinued the myasthenic signs were almost always fully reversible, recurring once again when treatment with penicillamine was started. In some instances a transitory symptomatic treatment with cholinesterase inhibitors was necessary. The occurrence of the myasthenic signs in these circumstances is probably similar to the anti-basal membrane nephropathy induced by penicillamine.

Adult↗
PubMed1976

Visual pattern evoked responses and blink reflexes in assessment of MS diagnosis. A clinical study of 135 multiple sclerosis/pathol.

VEPs were measured after pattern reversal in 135 MS patients and 30 control subjects. Neurological findings were documented in a standard manner. An extensive ophthalmological examination of all subjects was part of the study. The latency of P2 was abnormally delayed in 82% of the "definite", in 60% of the "probable" and in 65% of the "possible" MS groups respectively. The VEP was more often delayed in relation to ophthalmological disturbances. Changes in the MS classification had to be made in more than 10% of the patients, due to delay of VEP latency. These were patients with a "spinal" form of MS, which is known to create diagnostic problems. Optically and electrically evoked blink reflexes were recorded in 107 MS patients. All patients with mesencephalic lesions had delayed responses of the optically evoked reflex. 74% of the patients with caudal brainstem lesions had delayed latencies of the components of the electrically evoked blink reflex. The blink reflex was delayed in 18 additional patients without brainstem signs. The possibility of delineating clinically silent brainstem lesions by investigating blink reflexes is discussed.

Adolescent↗
PubMed1976

[Dyscephalia-cataracta congenita-hypotrichosis (DCH) syndrome (Ullrich-Fremerey-Dohna, Hallermann-Streiff, Francois). Report of a case showing extrapyramidal hyperkinesia and dementia (author's transl)].

In a 43-year-old man dyscephalia, cataracta congenita, and hypotrichosis were the outstanding features. These signs were first described in 1953 by Ullrich and Fremerey-Dohna as a clinical entity. Since 1958 the DCH syndrome was published under the synonyms of "Francois syndrome" and of "Hallermann-Streiff syndrome". However, as these authors did not add any essential details relevant for the classification of the syndrome we prefer to retain the term "Ullrich-Fremerey-Dohna syndrome". In our case in addition to the above mentioned and well known manifestations, extrapyramidal hyperkinesia of the choreoanthetotic type and servere mental deficiency accompanied by mild cerebral atrophy (revealed by pneumencephalography) were found.

Adult↗
PubMed1976

Axonal velocities of motor units in the hand and foot muscles of the baboon.

The axonal velocities of single motor units in the small hand and foot muscles of the baboon were studied by means of a collision technique which produced selective blocking of most of the fast-conducting fibres. In the abductor pollicis brevis muscle velocities ranged from 43 to 82 m/sec, and in the abductor digiti minimi muscle from 40 to 78 m/sec. In the extensor digitorum brevis muscle the range was 40-70 m/sec. When velocities were plotted as percentages of the maximal obtained in the same experiment, the range was similar in the 3 muscles studied. Most motor units had velocities greater than 65% of maximal but, in a few, velocities were between 55% and 65% of maximal. The possible relevance of these findings to human motor nerves is discussed.

Animals↗