PubMed Health⌕ Search

Biomedical subjects

J Vajsar

Publications and source records attributed to J Vajsar.

13 recordsLinked to original sources
PubMed1995

Arthrogryposis multiplex congenita due to congenital myasthenic syndrome.

Two children, now 5 1/2 and 6 years of age, presented as neonates with hypotonia, multiple joint contractures, ptosis, extraocular weakness, bulbar symptoms, and respiratory distress. Fluctuations and episodic exacerbations of weakness necessitated respiratory support. Both children are developmentally delayed and cannot walk independently, although one child underwent bilateral tenotomies. Biochemical investigations and electromyography, including slow-rate, repetitive nerve stimulation, were normal. Acetylcholine receptor antibodies in serum were absent. Single-fiber electromyography with axonal stimulation revealed prolonged mean jitter in the tibialis anterior and extensor digitorum muscles, with more than 2 abnormal individual jitter values in each muscle. Muscle biopsy demonstrated normal pattern and morphology of muscle fibers; immunohistochemical staining for cholinesterase was positive. Electron microscopy revealed abnormalities in motor endplates: atrophy, flattening of primary synaptic clefts, and paucity of side branches. These findings represent one of the postsynaptic abnormalities (i.e., acetylcholine receptor deficiency or paucity of synaptic folds). Both children improved clinically on pyridostigmine therapy. Arthrogryposis congenital multiplex due to congenital myasthenic syndrome, as diagnosed in our patients, has been reported once before. The diagnosis can be established by clinical history, neurologic examination, and electrophysiologic and pathologic findings. Clinical improvement can be achieved with high-dose anticholinesterase therapy.

Arthrogryposis↗
PubMed1994

Spontaneous non-traumatic anterior compartment syndrome with peroneal neuropathy and favorable outcome.

We report a girl who spontaneously developed an anterior compartment syndrome with an associated deep peroneal neuropathy. Initial nerve conduction studies (NCS) recorded from the extensor digitorum brevis muscle demonstrated prolongation of the distal latency to 7.8 msec (normal contralateral side, 3.6 msec), and reduction in amplitude of the compound muscle action potential to 0.1 mV (normal contralateral side, 9.9 mV). Electromyography of the tibialis anterior muscle showed an absence of motor unit potentials. Serum creatine kinase was markedly elevated to 12,769 IU. Computed tomography (CT) showed evidence of necrotic muscle. One month later, the foot drop, repeat NCS, and CT demonstrated a significant improvement with conservative management.

Anterior Compartment Syndrome↗
PubMed1994

Fetal nerve healing: an experimental study.

An experimental study was performed to assess fetal nerve repair and regeneration both qualitatively and quantitatively. The posterior tibial nerves in one hindlimb were transected in 16 midgestational fetal lambs and in their mothers. The nerves were then repaired with epineurial sutures and allowed to progress to 2, 4, 6, and 8 weeks postinjury. Qualitative assessment was performed through standard nerve histologic staining, including Luxol fast and toluidine blue for myelin and Bielschowsky stain for axons, and quantitative assessment through nerve conduction velocity studies and morphometry to determine mean myelinated fiber diameter, total fiber number, and density. A frequency histogram of the distribution of myelinated nerve fibers according to fiber diameter also was generated. In our model, the subsequent fetal nerve response to injury was characterized by earlier degeneration than in the adult counterparts. Repair and regeneration proceeded with dense collagenous scar formation in both groups. Electrophysiologic studies showed nerve impulse conduction across the repair site only at 6 and 8 weeks postinjury in both fetus and adult. Action potential amplitudes at 6 and 8 weeks were measured at 3 to 5 percent of control nerves in both nerve types. No electrophysiologic differences in the recovery of the injured fetal and adult nerves could be identified. Morphometry revealed that fetal nerve regeneration appeared to occur at a rate equivalent to that of the adult, although by 8 weeks the total percentage of remyelinated nerves appeared more complete in the fetus than in the adult (87 versus 59 percent), suggesting that fetal nerves may have a more favorable regenerative capacity than their adult counterparts.

Action Potentials↗
PubMed1993

Familial desminopathy: myopathy with accumulation of desmin-type intermediate filaments.

Two siblings developed cardiomyopathy several years before slowly progressive muscle weakness. Skeletal muscle biopsy specimens showed subsarcolemmal crescents of dark eosinophilic material in both type I and type II fibres. Immunohistochemically the subsarcolemmal material stained positively for the intermediate filament protein desmin and for the heat shock protein ubiquitin but for no other cytoskeletal proteins. Ultrastructurally the subsarcolemmal deposits consisted of aggregates of granular and filamentous material arising from Z-bands. Follow up muscle biopsies six years later showed an increased number of the muscle fibres that contained subsarcolemmal aggregates that stained positively for desmin and ubiquitin. These clinical and pathological features characterise a rare familial myopathy associated with an unusual distribution of desmin intermediate filament proteins in skeletal and probably also cardiac muscle.

Child, Preschool↗
PubMed1992

Somatosensory evoked potentials and nerve conduction studies in patients with Guillain-Barré syndrome.

Somatosensory evoked potentials, F-waves, and nerve conduction studies (NCS) were performed to determine their usefulness in detecting electrophysiologic abnormalities in 23 children in the acute stage of Guillain-Barré syndrome. The studies were performed on average 8.3 days after the onset of neurological symptoms, before the period of maximal weakness. All patients had at least one abnormal test. Somatosensory evoked potentials (SEP) showed most abnormalities: 91% abnormal recordings with posterior tibial nerve (PTN) stimulation and 68% with median nerve (MN) stimulation. The nerve conduction velocities were abnormal in 76% and 67% with PTN and MN stimulation, respectively. The F-waves were abnormal in 66% (PTN) and 56% (MN). The SEP studies were helpful in detecting proximal and central conduction abnormalities in 26% of patients, and they were more sensitive in detecting an abnormality when compared with F-wave recordings. Furthermore, in one patient with normal NCS and F-waves the prolonged lumbar potential-P35 conduction time of the PTN-SEP was the only abnormality found. SEP can detect an abnormality and thus support the clinical diagnosis of Guillain-Barré syndrome in the acute stage when the results of more conventional tests are inconclusive.

Adolescent↗
PubMed1987

Reliability estimates for steady-state evoked potentials.

The steady-state evoked potentials are most efficiently recorded using Fourier analysis. The reliability of this evoked potential is best estimated using either Hotelling's T2 or phase coherence. Using these techniques, the response to 500 Hz tones presented at a rate of 40/sec can be reliably recognized on average down to intensities of below 15 dB SL in an awake subject. Sleep significantly decreases the amplitude of the response and significantly raises the threshold for recognizing the response by 11 dB.

Adult↗
PubMed1979

[Measure of skin resistance (dermatophoria) in children with headaches (author's transl)].

In 1942 a curve of skin conductibility to direct current was described in Prague. It is a slow or steep rising of intensity in the few seconds following the introduction of the 12 V current to the hand from the dorsum to the palm. This method has been called dermatophoria. This curve is characteristical for a given individual and it is different in paretic (central and peripheral) limbs, generally more flat. In children the curves are steeper. However, abnormally steep there are in 57% of juvenile vasomotor headaches. Dermatophoria is therefore promising to be an objective method in diagnosis of children's headache.

Adolescent↗
PubMedDate not supplied

Infantile myositis presenting in the neonatal period.

Infantile myositis, observed in the neonatal period, is rare and may be confused with congenital muscular dystrophy. The patient presented here showed evidence of a myopathy with in utero onset with intrauterine growth retardation and decreased fetal movements. A muscle biopsy demonstrated characteristic perifascicular atrophy and inflammatory infiltrates. Initial magnetic resonance (MR) examination revealed high signal intensity in several proximal muscle groups. With subsequent corticosteroid treatment, the patient's symptoms, clinical course and MR findings have gradually improved. The diagnosis of infantile myositis should be established as early as possible, since proper treatment can lead to resolution of clinical symptomatology and MR findings.

Anti-Inflammatory Agents↗