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Biomedical subjects

R Kaji

Publications and source records attributed to R Kaji.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Familial Binswanger-type encephalopathy with Sneddon syndrome].

We reported a family with early onset cerebrovascular disease. Patient 1 (a 36-year-old man) demonstrated a combination of livedo reticularis and cerebral infarction as previously described as Sneddon syndrome. He also showed transient focal neurologic symptoms and mild dementia. Patient 2 (an elder sister of Patient 1) was suffering from migraine. Their father and paternal uncle died of cerebral infarction, which had developed in their thirties or forties. Patients 1 and 2 showed MRI findings compatible with encephalopathy with Binswanger-type. Contrary to the previous reports on Binswanger-type encephalopathy, both of these patients demonstrated decreased levels of fibrinogen as well as those of factor V, together with negative antiphospholipid antibody. Thus, juvenile onset, autosomal dominant inheritance, the diversity of clinical findings and the coagulopathy in this family were characteristic features. The level of thrombin-antithrombin III complex (TAT) was markedly increased in Patient 1. Treatment with antithrombin (argatroban 20mg i.v. everyday for 28 days) not only reduced the level of TAT but also improved the livedo reticularis and neurological findings. Although gene analysis has not been performed yet on this family, this condition is similar to cerebral autosomal dominant arteriopathy with subcortical infarct and leukoencephalopathy (CADASIL), which involve juvenile cerebral infarction and dementia as well as migraine.

Adult↗
PubMed1996

[The value of F-waves in an early electrodiagnosis of the lower cervical cord infarction].

In a case of infarction in the lower cervical spinal cord, F-waves were lost in the paralyzed hand muscles 48 hours after the onset, in spite of normal compound muscle action potentials (CMAP). Subsequently the amplitude of CMAP decreased markedly in size 14 days later, when needle EMG revealed acute denervation. At 11 days after the onset MRI demonstrated a linear lesion in the ventral portion of the lower cervical spinal cord suggesting ischemia. Thus, the loss of F-waves is useful in early diagnosis of the lower cervical spinal cord infarction, which reflects the decrease in the excitability of the anterior horn cells taking place soon after ischemic insult.

Action Potentials↗
PubMed1996

Hereditary neuropathy with liability to pressure palsies: distinguishing clinical and electrophysiological features among patients with multiple entrapment neuropathy.

Hereditary neuropathy with liability to pressure palsies is caused by deletion of the PMP-22 gene. As its relatively mild symptoms may escape detection by clinical examination alone, we screened the gene in patients with multiple entrapment neuropathy (MEN) that had been diagnosed by nerve conduction studies (NCS). Two of the eight patients with MEN had deletion of the gene. The characteristic features that distinguished them from the other MEN patients were predominantly sensory deficits associated with mild weakness and subclinical polyneuropathy as detected by NCS.

Adolescent↗
PubMed1996

Effect of photic conditioning on blink reflex recovery function in blepharospasm.

Patients with blepharospasm may have selective sensitivity to photic stimuli, for their symptoms are often aggravated after exposure to brightness. To investigate the pathophysiology underlying this phenomenon, we compared the effects of electric and photic conditioning on electrically-evoked blink reflex in 21 patients with blepharospasm and 11 age-matched control subjects. With electric conditioning, R1 was facilitated at inter-stimulus intervals (ISIs) of up to 100 ms in both groups. R2 was inhibited at all ISIs longer than 20 ms in the normals, but to a much lesser extent in the patients, suggesting increased excitability of the multi-synaptic reflex pathway. Compared to electric conditioning, photic conditioning was less potent in inhibiting R2 in the normals. In contrast, photic conditioning in the patients produced R2 inhibition as powerful as electric conditioning. These findings indicate that, in patients with blepharospasm, photic input has a relatively more profound inhibitory effect on the test blink reflex than electric conditioning as compared with normal subjects. The greater susceptibility of the brainstem interneurons to photic conditioning in blepharospasm may be related to the clinically-observed light sensitivity.

Adult↗
PubMed1996

[Treatment of spasticity with botulinum toxin and muscle afferent block].

Spasticity is partly caused by disinhibition of spinal stretch reflex activity and blocking of the group Ia afferents may improve its clinical symptoms. Since muscle afferent block has been successfully used for treating dystonia, this method may become useful for treating spasticity as well. We injected diluted lidocaine (0.5%, 50 ml/session) and ethanol (5 ml) into thigh adductors (for leg crossing), medial hamstrings (for medial rotation of the leg), quadriceps femoris (for hyperextension of the knee), tibialis posterior and triceps surae muscles (pes equinovarus deformity), biceps brachii and forearm flexors (for flexion deformities of the upper extremity) in 12 patients with spasticity. Although the duration of action was short (< 1 day) at first, it was gradually prolonged to several weeks by repeating the injection every 3-4 days. The final outcome was comparable to that obtained by botulinum toxin injection in the same group of patients. This method may prove its promise as a means of treating spasticity.

Adult↗
PubMed1995

A novel point mutation in the mitochondrial tRNA(Ser(UCN)) gene detected in a family with MERRF/MELAS overlap syndrome.

We found a new point mutation in the mitochondrial tRNA(Ser(UCN)) gene in a family with MERRF/MELAS overlap syndrome by screening for heteroplasmy by means of chemical cleavage of mismatch (CCM). Our strategy was based on the previous observations that most pathogenic mtDNA mutations in mitochondrial encephalomyopathies are heteroplasmic, whereas almost all neutral mitochondrial polymorphisms are homoplasmic. CCM followed by nucleotide sequencing of the corresponding region of the mitochondrial genome revealed a heteroplasmic mutation at nt 7512 in the tRNA(Ser(UCN)) gene. The 7512 (T to C) mutation disrupts a highly conserved base pair in the acceptor stem, and this mutation was not found in any of 120 normal controls, or in 43 patients with mitochondrial diseases. The proportion of the mutant mtDNA was 93% in muscle, 76 and 87% in the blood of the patients. A family member without apparent neuromuscular symptoms carried less mutant mtDNA. These findings support the view that this mutation is pathogenic in this family. Detection of heteroplasmy by CCM is an efficient means of screening pathogenic mtDNA point mutations.

Adult↗
PubMed1995

Tonic vibration reflex and muscle afferent block in writer's cramp.

Patients with focal dystonia take advantage of certain cutaneous or proprioceptive sensory inputs to alleviate their symptoms ("sensory trick"). We examined the effects of increasing muscle spindle activity by the tonic vibration reflex maneuver and decreasing it by intramuscular injection of lidocaine. The vibration was applied to the palm or the tendon of forearm muscles in 15 patients with writer's cramp and 15 age-matched normal subjects. In 11 patients, the vibration induced dystonic postures or movements typical of those seen during writing. Normal subjects showed either no response to the vibration or a gradually developing tonic vibration reflex only in the wrist and finger flexors, which produced visible movements with a significantly longer latency (12.5 +/- 6.7 seconds [mean +/- standard deviation]) than what was observed in the patients (2.7 +/- 2.5 seconds, p < 0.0001). Local injection of lidocaine (0.5%, 5-40 ml/muscle) attenuated the tendon reflex with relatively little effect on the M response. Injection into muscles with increased activity produced marked reduction of dystonic movements and significant clinical improvement in 13 patients, whereas injection into the other muscles had no effect. The clinical benefit lasted for 1 to 24 hours after injection. In 13 patients who had additional injections of 10% ethanol, which blocks sodium channels for a longer period than does lidocaine, the duration of action was prolonged to 5 to 21 days. These findings suggest that muscles causing dystonic movements have abnormal sensitivities to vibration at rest and that muscle afferents may play a pivotal role in producing dystonic movements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Pain-related somatosensory evoked potentials following CO2 laser stimulation of foot in man.

Since our previous study of pain somatosensory evoked potentials (SEPs) following CO2 laser stimulation of the hand dorsum could not clarify whether the early cortical component N1 was generated from the primary somatosensory cortex (SI) or the secondary somatosensory cortex (SII) or both, the scalp topography of SEPs following CO2 laser stimulation of the foot dorsum was studied in 10 normal subjects and was compared with that of the hand pain SEPs and the conventional SEPs following electrical stimulation of the posterior tibial nerve recorded in 8 and 6 of the 10 subjects, respectively. Three components (N1, N2 and P2) were recorded for both foot and hand pain SEPs. N1 of the foot pain SEPs was maximal at the midline electrodes (Cz or CPz) in all data where that potential was recognized, but the potential field distribution was variable among subjects and even between two sides within the same subject. N1 of the hand pain SEPs was maximal at the contralateral central or midtemporal electrode. The scalp distribution of N2 and P2, however, was not different between the foot and hand pain SEPs. The mean peak latency of N1 following stimulation of foot and hand was found to be 191 msec and 150 msec, respectively, but there was no significant difference in the interpeak latency of N1-N2 between foot and hand stimulation. It is therefore concluded that N1 of the foot pain SEPs is generated mainly from the foot area of SI. The variable scalp distribution of the N1 component of the foot pain SEPs is likely due to an anatomical variability among subjects and even between sides.

Adult↗
PubMed1995

Peri-rolandic and fronto-parietal components of scalp-recorded giant SEPs in cortical myoclonus.

Scalp topography of giant SEPs to median nerve stimulation was studied in 4 patients with cortical myoclonus of various etiology. The positive peak (P30) at the contralateral parietal area was simultaneously accompanied by a negative peak at the frontal area (N30), and at least one of these two peaks was enhanced in 2 patients. Another positive peak (P25) and a negative peak (N35) were also identified at the peri-rolandic area with different latency from P30 and N30, respectively, in all patients. N35 was enhanced in 3 patients, and P25 in 2 patients. It is concluded that, as seen in normal subjects, tangential (P30-N30) and radial (P25 and N35) components of SEPs are most likely distinguishable in giant SEPs, and that either one or both of those components is enhanced in different ways depending on the patients.

Adolescent↗
PubMed1995

Physiological study of cervical dystonia. Task-specific abnormality in contingent negative variation.

To investigate the pathophysiology of dystonia, we recorded contingent negative variation (CNV) in 12 patients with cervical dystonia and in 12 age-matched normal subjects. In a simple reaction time paradigm, the subjects were given a pair of a warning stimulus and a subsequent stimulus that triggered head rotation to either side or extension of the fingers. In normal subjects, CNVs for head rotation were not affected by neck muscle pre-activation simulating torticollis, and were always symmetrical with equally high amplitudes over the frontal and central leads. By contrast, CNVs for finger movement had the maximum over the central lead and showed a characteristic distribution; those for the right finger movement had the left hemisphere dominance, whereas those for the left finger movement had similar amplitudes over both hemispheres. In patients with rotatory torticollis (rotatocollis), the components of CNVs for head rotation were markedly attenuated in all the leads, except for the initial negative deflection (orienting response). As a whole, cervical dystonia patients had significantly lower amplitudes of late CNVs for head rotation than normal subjects (P < 0.001), whereas late CNV amplitudes in finger extension did not differ in the two groups. Their reaction times for head rotation were similar, but durations of EMG activities were prolonged in the patients because of co-contractions of the antagonists. The task-specific CNV amplitude loss is therefore not explained by reaction times or by the abnormal neck muscle activities prior to the movement, but it reflects a failure of neural activities preparing for a phasic neck movement, resulting in co-contraction of the agonists and the antagonist. Dystonia may be associated with defective retrieval or retaining of specific motor programmes or subroutines in response to sensory stimuli.

Adult↗
PubMed1995

Presence of Bereitschaftspotential preceding psychogenic myoclonus: clinical application of jerk-locked back averaging.

The method of jerk-locked back averaging was applied to six patients with clinically diagnosed psychogenic myoclonus. Five patients had a slow negative EEG shift corresponding to Bereitschaftspotential at the central region starting 0.7 to 2.1 seconds before the onset of the myoclonic jerk. One patient had no potential preceding the myoclonic jerk, whereas a small negative potential preceded the voluntary movement mimicking the jerk. The demonstration of Bereitschaftspotential before an apparently involuntary myoclonic jerk helps the clinical diagnosis of psychogenic myoclonus, although the absence of Bereitschaftspotential does not necessarily indicate that the movement is involuntary. Jerk-locked back averaging is clinically useful as a specific laboratory examination in this condition.

Adult↗
PubMed1995

Comparison of therapeutic efficacies of type A and F botulinum toxins for blepharospasm: a double-blind, controlled study.

Type F botulinum toxin can be used for treating patients with dystonia who become refractory to type A toxin injection due to antibody development. We compared the therapeutic efficacy of type F botulinum toxin to that of type A toxin in a self-controlled, double-blind clinical trial. In nine patients with blepharospasm, we injected type A toxin on one side and the same units of type F toxin on the other side. Although the onset of clinical effect, maximal benefit, and adverse reactions were similar between type A and F toxins, the duration of the clinical effect was significantly shorter on the side injected with type F toxin. Although type F toxin proved its promise as an alternative to type A toxin, its usefulness is limited by the shorter duration of action.

Aged↗
PubMed1995

[The clinical usefulness of botulinum toxin type A for spasmodic torticollis and facial spasm].

We studied the clinical effectiveness of botulinum toxin type A for spasmodic torticollis and that for facial spasm by multicenter, non-blinded study. The freeze-dried crystalline botulinum toxin type A (AGN 191622; Allergan Inc., Irvine, CA) was injected into the hyperactive muscles and the clinical course was followed for 22 weeks. Repeated injections were done, if necessary, with an interval of 4 weeks. The toxin was highly effective in both disorders. In spasmodic torticollis, clinical severity improved in 38 (63.3%) and the global improvement was seen in 39 (65.0%) out of 60 patients. Subjective improvement was seen in 56 (93.3%). In facial spasm, 52 (92.9%) out of 56 patients improved after the treatment. Unfavorable reactions, mainly consisting of neck muscle weakness and dysphagia in torticollis and facial weakness in facial spasm, were mostly due to the excessive action of the toxin. They were usually mild and transient. No patients discontinued the trial because of side effects. Botulinum toxin injection is a very useful and safe method for the symptomatic treatment of spasmodic torticollis and facial spasm.

Adolescent↗
PubMed1995

[Dose-response relationship in the treatment of cervical dystonia with botulinum toxin type A (AGN 191622)--a phase II study].

Injection of botulinum toxin type A has been the treatment of choice for spasmodic torticollis for several years. Although previous reports demonstrate its effectiveness and safety, the treatment strategy has been empirical. The present study, using the freeze-dried crystalline botulinum toxin type A (AGN 191622; Allergan Inc., Irvine, CA), aimed to compare the efficacy among three treatment groups divided into low, medium and high dosage levels. Fifty-one patients who entered the study were grouped into low-dose (60 units/session), medium-dose (120 units/session) and high-dose (240 units/session) groups. Two patients (one in low-dose group and the other in high-dose group) were excluded from the assessment of efficacy because they dropped out in the early phase of the study. One experienced worsening of an existing psychosis and the other developed an acute respiratory infection. Injection sites were decided individually by palpation. If the clinical response was not satisfactory four weeks after an injection, the patient was re-injected with the same dose of toxin. The follow-up period was 14 weeks from the initial injection. The results showed that the high-dose group improved more than the other groups in the parameters of severity of symptoms and subjective benefit (p = 0.000). Also, fewer injections were required in the high-dose group to achieve substantial clinical benefit. Although the mean reduction in Tsui's score was not statistically significant among the groups, the "marked improvement" was seen more frequently in the high-dose group (p = 0.033). Unfavorable adverse effects including excessive weakness and dysphasia were always mild and transient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗