Comparison of Visual Evoked Potential Components between Laser and Cathod-Ray Tubes Stimulation in Healthy Human Subjects

We studied the differences in latency and amplitude between the laser stimulated visual evoked potentials (VEPs) and the cathode-ray tubes (CRTs) stimulated VEPs to estimate the risk of inducing photosensitive epilepsy by laser displays. Twenty healthy subjects were recruited for the study. Red and blue light stimulations were flashed in 1, 7.5 and 15Hz. The latency of P1, N1, P2 and N2 in 1 Hz stimulation revealed no significant difference by a paired t test between laser and CRT stimulation. The peak-to-peak amplitude was significantly smaller with red or blue laser stimulation than with red or blue CRT stimulation, for PI-N1 and N1-P2 at 7.5Hz stimulation, and for N1-P2 and P2-N2 at 15Hz stimulation. We therefore postulate that laser does not produce more excitability to occipital cerebral cortex than CRT does. There was no evidence to say that laser stimulation is more dangerous as the risk of inducing photosensitive epilepsy than conventional CRT stimulation

富士川流域におけるCreutzfeldt-Jakob病の疫学的検討

1970年代以降,静岡,山梨両県の富士川流域にCreutzfeldt-Jakob病(CJD)が多いことは知られていたが,筆者らは同地域に位置する共立蒲原総合病院で1999年の1年間に3例のCJD患者を経験したことから,静岡,山梨両県の36施設に対し,1990年から1999年の10年間にわたるCJD患者についてのアンケート調査を行なった.36施設中26施設から文献例を含む合計34例のCJD患者が確認された.症例は男性16例,女性18例で,平均発症年齢は62.5±10.7歳であった.遺伝子変異が10/34例(29.4%)にみられ,全例がcodon 200の変異(CJD^)であり,そのうち2家系に家族内発症を認めた.臨床所見では高率にミオクローヌス(95.7%)と脳波上の周期性同期性放電(periodic synchronous discharge,PSD)(95.7%)を認め,従来の孤発例やCJD^の特徴と一致していた.過去10年間では富士川中流地区に,1999年の1年間では下流地区に,それぞれCJD患者の有為な集積が確認された(ボアソン分析でpの10例のうち8例が富士川流域(7例が中流～下流地区)の出身であったことから,同地区がCJD^の主たる集積地区と考えられた.また周辺の静岡市から三島市にかけても症例(CJD^2例を含む)が散見され,同地区まで含めた範囲をCJD関連地域として注目すべきと考えた.An epidemiological study of Creutzfeldt-Jakob disease (CJD) was carried out during the period between 1990 and 1999. A total of 34 cases with CJD was collected from the information provided by neurologists, psychiatrists, and neurosurgeons in Shizuoka and Yamanashi Prefecture. There was no significant difference between males and females. The average age of onset was 62.5 years, with high occurrence seen in patients in their fifties, sixties, and seventies. The mean duration of CJD was 7.3 months. There were no cases with a cadaveric dural graft. There were two families with CJD patients having codon 200 mutations. Myoclonus occurred in 95.7% of cases and there were electroencephalographic (EEG) tracings with periodic synchronous discharges (PSD) in 95.7% of the cases. Ten patients had a mutation at codon 200 of prion protein gene (CJD^) . In the middle reaches of the Fuji River basin (Yamanashi Prefecture), the retrospective incidence of CJD between 1990 and 1999 was 5.77 cases/million/annum; highly significant clustering (p = 0.01) was confirmed in this area. The point prevalence rate in 1999 at the lower reaches of the Fuji River (eastern part of Shizuoka Prefecture) was 9.78 cases/million/annum. These results demonstrated significant clusters of CJD patients at the middle and lower reaches of the Fuji River. The incidence of CJD^ appeared to be much higher in these areas than other areas in Japan

ミトコンドリア脳筋症における少量ジクロロ酢酸療法の臨床的評価 : ジクロロ酢酸少量内服療法が卒中様発作抑制に有効であった5症例について

筋生検・ミトコンドリアDNA遺伝子診断などによりMELASと診断され,脳卒中様発作を繰り返し,頭部MRIで病変が確認された成人MELAS5症例に,少量のジクロロ酢酸を含むLiverall^を投与し,脳卒中様発作を抑制できるか臨床経過を検討した.内服開始後は,全例で頭部MRI画像上病変を認める脳卒中様発作は生じなかった.従来小児科領域で報告されていた必要量よりも少量で発作を抑制できる可能性があると考えられた.しかし,血清中の乳酸・ピルビン酸は異常値を示す場合もあり,痙攣発作やイレウスなどの合併症状を呈する症例も2例あり,今後の検討が必要と考えられた.本論文の要旨は,第44回日本神経学会総会(横浜,2003年5月)において発表した.In five adult patients with MELAS, we evaluated clinical symptoms, FLAIR and DWI brain MRI, and serum level of lactate and pyruvic acid, to assess whether stroke-like episodes in MELAS are suppressed by small dose of dichloroacetate. After beginning oral therapy of Liverall^ for MELAS, none of the five cases showed any occurrence of the stroke-like episodes associated with brain MRI lesions. We noticed that the stroke-like episodes were suppressed by using a smaller dose of dichloroacetate, compared with the dose required for therapy of pediatric patients with MELAS. In spite of favorable effect of Liverall^ for MELAS in symptomatic and MRI evaluations, the serum level of lactate and pyruvic acid continued to show abnormal values and convulsive seizures or ileus occurred in a few cases. Further investigations are required to know whether Liverall^ is a useful therapeutic drug

Serum thiamine level during the initiation term of hemodialysis

It has been reported that thiamine deficiency is often seen in hemodialysis (HD) patients because of dietary restrictions as well as its loss during dialysis sessions. We studied the serum thiamine level before and after dialysis sessions during the initiation term of HD. Forty CKD patients who hospitalized to newly begin chronic HD were studied. We compared the serum thiamine levels at the first and the last HD sessions in our hospital. The serum thiamine level at the first HD decreased from 25.47±10.07 to 23.55±9.46 ng/ml (before and after HD session, respectively, p<0.05, paired t-test). At the last HD session in our hospital, the serum level of thiamine also decreased from 27.44±11.37 to 25.71±10.80 ng/ml (before and after HD session, respectively, p <0.05). Although water-soluble vitamins such as thiamine are lost during dialysis session, serum thiamine level tended to restore spontaneously during the hospitalization (25.47±10.07 vs. 27.44±11.37, pre HD value, p=0.09). A three months-follow up measurement after initiation of HD, which is now in progress (so far n=3), revealed increase of serum thiamine level in all patients (35.33±7.37 ng/ml). It may reflect the improvement of nutritional status after the initiation of HD, and suggests the loss of thiamine by HD procedure can be covered