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Biomedical subjects

H C Hopf

Publications and source records attributed to H C Hopf.

At least 109 records · Page 6Linked to original sources
PubMed1992

Localization of emotional and volitional facial paresis.

Emotional facial paresis is characterized by impaired activation of face muscles with emotion but normal voluntary activation. We report seven patients with this sign. Their lesions involved the frontal lobe white matter, the striatocapsular territory, the anterolateral thalamus and insula, the posterior thalamus and operculum, and the mesial temporal lobe and insula each in one patient, and the posterior thalamus in two patients. Volitional facial paresis affects facial movements with voluntary effort, sparing activation on emotion. We report four such patients, with lesions involving the motor cortex in one and the pyramidal tract in the cerebral hemisphere in three.

Adult↗
PubMed1992

Persistent unilateral tibialis anterior muscle hypertrophy with complex repetitive discharges and myalgia: report of two unique cases and response to botulinum toxin.

Unilateral enlargement of the tibialis anterior muscle associated with complex repetitive discharges occurred over several months in two patients and was preceded by pain and numbness in the lower leg. Neuroradiologic investigations excluded a compressive radiculopathy, but pharmacologic and neurophysiologic studies suggested a neurogenic basis for the muscle hypertrophy. Botulinum toxin A injection into the hypertrophied muscles led to a decreased muscle volume and cessation of muscle pain.

Adult↗
PubMed1992

[Pauses in masseter innervation (silent periods) following stimulation of the median nerve, the cervical plexus and the mental nerve].

In 20 healthy volunteers, a bilateral masseter silent period (Mass SP) was constantly evoked by stimulating the mental nerve (latency: x = 13.95 +/- 4.3 ms) and cervical plexus (latency: x = 20.2 +/- 3.7 ms). This was also the case with median nerve stimulation (latency: x = 54.4 +/- 13.1 ms) in 19 of the 20 subjects. Utilizing magnetic stimulation of the lumbal roots, the Mass SP was elicited in 3 of 10 subjects and showed marked habituation. No Mass SP was observed with stimulation of the long nerves of the lower limbs. The central loop of the reflex represents a stable connection between the spinal cord cervical region and the trigeminal motor nuclei. The Mass SP may be abolished in circumscribed brainstem lesions and thus may serve for localizing lower brainstem involvement.

Adult↗
PubMed1991

Pupil-sparing oculomotor nerve palsy due to midbrain infarction.

Vasculopathic oculomotor nerve palsies with pupillary sparing are thought to be due to ischemic damage to the nerve in the subarachnoid space or the cavernous sinus. We present two cases of patients with isolated pupil-sparing oculomotor nerve palsies due to midbrain infarcts. Focal ischemic midbrain lesions should be considered in cases of pupil-sparing oculomotor nerve palsies.

Adult↗
PubMed1991

Midbrain vs. pontine medial longitudinal fasciculus lesions: the utilization of masseter and blink reflexes.

Masseter (MR) and blink reflexes (BL) were investigated in 51 patients with internuclear ophthalmoplegia (INO) due to multiple sclerosis (28) and lacunar infarction (23). The MR was abnormal in 20 of 23 cases with bilateral INO and in 21 of 28 with unilateral INO. The R1 component of the BL (BL-R1) was abnormal in 7 of 23 patients with bilateral INO and 10 of 28 with unilateral INO. Combined MR and BL-R1 changes occurred in 8 of 28 cases with unilateral INO and 7 of 23 with bilateral INO. The findings provide evidence for a rostral/caudal localization of lesions within the medial longitudinal fasciculus causing INO on the basis of MR and BL-R1 abnormalities. An abnormality limited to MR suggests a midbrain location in 58.8% of patients while abnormal BL-R1 with or without an associated MR change suggests a rostral pontine location in 35.3%.

Blinking↗
PubMed1991

Spheroid-cytoplasmic complexes in a congenital myopathy.

The most striking pathological finding in the deltoid muscle biopsy specimens of 2 unrelated adult male patients consisted of large spheroid-cytoplasmic complexes of intricate structure, as previously described only under experimental conditions (Chou and Mizuno, 1986). These large cytoplasmic masses were characterized by a granular centre and a filamentous halo. Immunohistology revealed the presence of intermediate filaments of the desmin and vimentin types. Clinically, both patients showed mild and slowly progressive proximal myopathy of adult onset. In one patient, the myopathy was strongly suspected to be inherited. In concordance with previous reports on cytoplasmic and spheroid body congenital myopathies, these spheroid-cytoplasmic bodies further enlarge the spectrum of late onset congenital myopathies.

Adult↗
PubMed1990

Temperature dependence of the electrical and mechanical responses of the adductor pollicis muscle in humans.

Changes at low temperatures of the electrical and mechanical activity of the adductor pollicis muscle were studied in 10 volunteers. Decreasing temperatures resulted in increased amplitude and duration of the negative phase and peak-to-peak amplitude of the evoked muscle action potential. Distal latency, electromechanical latency, contraction time, and half-relaxation time were also increased while isometric force, contraction velocity, and relaxation velocity were decreased. The increase of contraction time is greater over the temperature range below 28 degrees C than above 29 degrees C. Skin temperature differs significantly from muscle temperature, showing about 3 degrees C lower values during cooling and up to 4 degrees C higher values during rewarming with radiant heat.

Action Potentials↗
PubMed1990

Forearm ulnar-to-median nerve anastomosis of sensory axons.

A 22-year-old man showed electrophysiological evidence of an ulnar-to-median nerve communication involving only sensory fibers. The nerve action potentials evoked by stimulation of the middle finger (ulnar side) and the ring finger (radial side) digital nerves were propagated with the median nerve at the wrist and the ulnar nerve at the elbow. He was the only subject among 30 studied with this abnormality.

Action Potentials↗
PubMed1990

Fasciculations due to verapamil in a patient with neuropathy.

A patient with pre-existing peripheral neuropathy developed generalized fasciculations under verapamil which ceased after discontinuation of the drug. It is suggested that the increase in acetylcholine (ACh) release at the neuromuscular junction by verapamil may trigger fasciculation in the state of regeneration at ACh-sensitive sites of axon terminals and immature axon sprouts.

Aged↗
PubMed1990

Alcohol-dependent unilateral vestibular impairment persisting after a closed head injury.

A 20-year-old man suffered a closed head injury followed by symptoms of right-sided labyrinthine concussion with complete clinical recovery within 3 weeks. Episodic vertigo and ataxic gait occurred after the ingestion of small amounts of alcohol over the next 2 years. Electro-oculography revealed a right-sided peripheral type vestibular lesion, only after taking alcohol. This was interpreted as an alcohol-induced impairment of central compensation following an incomplete recovery from right-sided labyrinthine trauma.

Adult↗
PubMed1990

Pontine supranuclear facial palsy.

Two patients presented with a unilateral supranuclear facial palsy. Additional dysarthria was attributed to the pontine origin documented by magnetic resonance imaging on the contralateral side. The pontine disorder also was indicated by an isolated delay of the blink reflex R1 component or of the masseter reflex. We attribute the facial palsy to a lesion of a supranuclear fiber bundle supplying the facial nucleus. The location of the lesions favors these fibers taking a separate course from the main pyramidal tract at the mid- to upper pontine level.

Aged↗
PubMed1990

Diabetic 3rd nerve palsy: evidence for a mesencephalic lesion.

Eleven consecutive adult chronic diabetic patients presented with an isolated 3rd nerve palsy (8 with pupillary sparing) of which 10 had abnormal ipsilateral or bilateral masseter reflexes (MassR). Three patients had an MRI lesion in the ipsilateral oculomotor fasciculus and 3 had subsequent mild brainstem signs. An additional 13 patients with Weber's syndrome had similar ipsilateral or bilateral MassR abnormalities, while 7 patients with 3rd nerve palsies on a known extra-axial basis had none. The findings suggest that an isolated diabetic 3rd nerve palsy, with or without pupillary sparing, is much more likely on the basis of a focal mesencephalic infarct than a peripheral nerve lesion.

Aged↗
PubMed1990

[The temporal dynamics of EEG changes in the early phase of herpes simplex encephalitis].

In 19 patients with herpes simplex encephalitis 64 EEG examinations and 36 CT scans have been performed within the first two weeks after onset of clinical symptoms. During the first 10 days periodic discharges were present in 12 patients. At this time CT scan was negative in 5 of them. Five of 7 patients without but only 4 of 12 patients with this EEG pattern survived without clinical abnormalities. Five patients with periodic discharges died during the acute stage of the illness. In patients with poor outcome including major clinical deficit or death periodic discharges were present during successive investigations until day 14. In the group of patients with good clinical improvement these EEG changes were only detected in a single recording until day 7. Periodic discharges have to be considered as an indicator of a poor prognosis whenever they are present for a longer period.

Adolescent↗
PubMed1989

Internalized myofiber capillaries: observations on their origin and clinical features.

Internalized capillaries limited to type 1 muscle fibers were noted in seven patients. They occurred in each case in association with a similar admixture of neurogenic and myopathic features that included atrophic and hypertrophic fibers, internal nuclei, fiber splitting, and endomyseal and perimyseal fibrosis. Internalized capillaries in enlarged type 1 fibers arose from fiber splits on step section study of four patients. They occurred in the gastrocnemius, quadriceps, and soleus muscles from patients with a variety of disorders that included Becker dystrophy, diabetes mellitus and strenuous leg activities, Achilles tendon rupture, and myotonic dystrophy. Exercise-induced myalgias were noted in the four patients with the most plentiful intramuscular capillaries, and in three of these muscle hypertrophy was present. The concurrence of internalized myofiber capillaries and exercise-induced myalgias may represent an associated biochemical/pathological defect.

Adolescent↗
PubMed1989

End-plate dysfunction in acute organophosphate intoxication.

Acute organophosphate intoxication resulting from suicide attempts in 14 patients produced a series of electrophysiologic abnormalities that correlated with the clinical course. Spontaneous repetitive firing of single evoked compound muscle action potentials (CMAP) was the earliest and most sensitive indicator of the acetylcholinesterase inhibition. A decrement of evoked CMAP following repetitive nerve stimulation was the most severe abnormality. At the height of the intoxication no CMAP was evoked after the first few stimuli. The decrement-increment phenomenon occurred only at milder stages of intoxication and its features are characteristic of acetylcholinesterase inhibition. These electrophysiologic features proved to be the most useful for determining initial severity and clinical course of the acute organophosphate intoxication and differentiated this syndrome from those of myasthenia gravis, Eaton-Lambert syndrome, and botulism.

Adult↗
PubMed1989

[The decrement-increment phenomenon in disorders of neuromuscular transmission by inhibition of acetylcholinesterase].

Repetitive stimulation of the median nerve elicited a so far unknown course of the muscle action potentials in four patients with organophosphate intoxications. The amplitude of the initial muscle action potential decreased with the second stimulus and gradually increased to normal values by subsequent stimuli. With the second stimulus a loss of the repetitive muscle action potentials occurred. The Decrement-increment phenomenon was seen in early and/or late stages of severe intoxications when fasciculations were prominent. We suppose that the repetitive muscle action potential following the first stimulus results from backfiring. The second orthodromic nerve action potential collides with this antidromic activity leading to a partial extinction. Loss of backfiring with the second stimulus abolishes the phenomenon of collision and enables a recovery of the muscle action potential amplitudes.

Cholinesterase Inhibitors↗