[Effect of septal lesions on the hippocampal EEG and behavior during DRL learning in the rabbit]

We had reported that hippocampal high frequent activity at 8-10 Hz (alpha-burst) appeared during approach and lever press with the progress of DRL learning. In this study, effect of bilateral septal lesions on hippocampal EEG (especially on alpha-burst) and behavior during 10 second DRL learning was investigated in thirteen rabbits. Using the atlas of Sawyer et al., bipolar electrodes were implanted chronically in bilateral septum at coordinates of A 1-2, L 1 and D 10-11 and dorsal hippocampus at P 3-5, L 4-6 and D 7-8. Septal lesion was made by using 8-mA DC currents for 15-50-sec period enough to abolish hippocampal theta activity. DRL learning was performed after septal lesions in five rabbits. In this group, acquisition of learning was disturbed and rhythmic slow activity of the hippocampus was markedly reduced. However, movement itself was not disturbed. Although hippocampal activity recovered gradually with the progress of session, alpha-burst was not observed by the 70th session. In eight rabbits, septal lesions were made after completion of DRL learning which required 40-50 sessions. In this group, the preservation of DRL learning was disturbed and relearning was not completed by the 30th session after septal lesions. Hippocampal rhythmic activity was remarkably reduced and alpha-burst was disappeared. But, voluntary movement itself was not altered. There are several theories concerning with hippocampal rhythmic slow activity. Some author emphasized that hippocampal rhythmic activity appeared at the time of voluntary movement and it had close relation to voluntary movement.(ABSTRACT TRUNCATED AT 250 WORDS)

Statistical analysis of symptoms and signs in pediatric patients with peptic ulcer

It is not well known which symptoms or signs related to peptic ulcer are crucial for its diagnosis in children. In order to clarify this problem, we evaluated the sensitivity, specificity, and positive and negative predictability of 13 ulcer-related symptoms and signs. The data of 160 patients, who were suspected of having peptic ulcer and had undergone endoscopic examinations, were studied. It was significant that five symptoms, i.e., presence of pain in the epigastrium, relationship between the time of pain and that of eating, family history, vomiting, and bleeding, were frequently found in ulcer patients. There was, however, no symptom or sign that predicted by itself precisely the existence of a peptic ulcer. Thus, we computed a discriminant function by combining the data by multivariate analysis. With this score, we could predict the existence of ulcer more precisely. Finally, it was concluded that epigastric pain, food-related pain, vomiting, bleeding, and family history were crucial factors for the diagnosis of peptic ulcer in childhood and that an overall consideration of symptoms and signs was needed for the evaluation of these factors.

[CT-guided stereotaxic evacuation of cerebellar hematoma--lateral approach]

Stereotaxic lateral approach for cerebellar hematoma is presented using Leksell's CT-stereotaxic system. All of the procedures are performed in the CT room. Patient's head is turned to contralateral side of the hematoma 30 to 40 degrees with slight flexion of the neck. Stereotaxic apparatus is secured to the head under local anesthesia. Hematoma is confirmed by computerized tomograms. Three dimensional coordinates of the target point (center of the hematoma) are measured from the vertical and diagonal rods of Leksell's system. Linear skin incision 4 cm in length is made on retromastoid area. Burr-hole is put on just lateral position of the target point, usually 5 to 6 cm posterior and 1 cm above from the external auditory meatus. Transverse or sigmoid sinus does not appeared through the burr-hole by this approach. Specially made Dandy's cannula (3.0 mm in diameter, 220 mm in length) is inserted into the target point, and manual evacuation of the hematoma is performed carefully using a syringe. Then Dandy's cannula is replaced by silastic drainage tube (3.5 mm in diameter), and 6,000 Units of Urokinase solved in 2 ml of saline is administered to the hematoma cavity. Dissolved hematoma is aspirated every 24 hours until the most of the hematoma is evacuated. We operated three cases of cerebellar hematoma by this method with favorable results. Advantages of this method are as follows: Operative invasion is minimal; The surgeon can check the residual hematoma and position of the tip of cannula even at operation, if necessary.

[EEG findings in moyamoya disease in children--with special reference to the genesis of re-build up]

EEG findings in Moyamoya diseases in children are characterized by build up during hyperventilation and re-build up after hyperventilation. We examined EEG, tcPO2, tcPCO2 and respiratory curves during and after hyperventilation in 10 cases of typical Moyamoya disease in children. In all of the cases, tcPCO2 decreased gradually by hyperventilation, and its level was about 50% of the pre-hyperventilation level at the end of hyperventilation. It took about five minutes for the tcPCO2 level to return to the pre-hyperventilation level. On the other hand, tcPO2 was increased by hyperventilation. However, it decreased down to 50% of the pre-hyperventilation level within a few minutes after hyperventilation because of the following decrease in the respiratory rate, and it took 5 to 10 minutes to return to the pre-hyperventilation level. Sequential changes in tcPCO2 and tcPO2 showed good correlation with the biphasic change in EEG by hyperventilation in children with Moyamoya disease. The decrease in tcPO2 after hyperventilation seemed in particular to play an important role in the appearance of re-build up. We also examined tcPO2 and tcPO2 during and after hyperventilation in 9 cases of normal children. Sequential changes in tcPCO2, tcPO2 and the respiratory rate were the same as those in children with Moyamoya disease, but re-build up was not observed. In 4 cases of Moyamoya disease we examined the sequential changes in EEG, tcPCO2, tcPO2 and the respiratory rate under the inhalation of 100% O2 and 8% CO2 air.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation-induced formation of apoptotic bodies in rat thymus

The process of interphase death of thymocytes in whole-body X-irradiated rats were studied. Cell size distribution analysis indicates that cell fragments (= apoptotic bodies) appeared in the thymus and increased in number depending on dose (200-1000 R) and time (2-6 hr) after irradiation with corresponding decrease in normal-size thymocytes. Occurrence of nuclear fragmentation in association with the cellular fragmentation was proved with cytofluorometric determination of DNA content in individual cells. Scanning electron microscopic observations also revealed extensive fragmentation of cells in the irradiated rat thymus. The results show clearly that cells as well as nuclei fragment rapidly into smaller pieces of various sizes in the irradiated rat thymus as commonly observed with apoptosis.

Prevention of interphase death in rat thymocytes by bisulfite

The effect of sodium bisulfite, a specific inhibitor of chromatin proteolysis, on radiation damage in rat thymocytes in vitro was examined. Rat thymocytes irradiated with 1 kR X rays in vitro were incubated at 37 degrees C with 10 mM glucose for 4 to 6 hr. During that time development of interphase death as judged by erythrosin B uptake, release of low molecular weight DNA (free DNA), and reduction in cell size was measured. Sodium bisulfite added to the cells at the beginning of incubation exerted a marked preventive effect on radiation damage. The effect was enhanced with increasing concentration of bisulfite from 0.25 to 2 mM. The effect of bisulfite was reversible; i.e., removal of bisulfite from the cells resulted in the reappearance of the radiation damage.

Purification and characterization of amino-acid N-choloyltransferase from human liver

Amino-acid N-choloyltransferase was purified from human liver. The procedure resulted in about 100-fold enriched activity and glycine- and taurine-dependent activities co-purified and did not separate to any extent in any of the steps. The final enzyme preparation had an apparent molecular mass of 100 kDa by gel filtration, 118 kDa by sucrose density gradient centrifugation and was composed of two identical subunits which had a molecular mass of 52 kDa, as judged by dodecyl sulfate polyacrylamide disc gel electrophoresis. The glycine- and taurine-dependent activities showed optima at pH 7.2 and pH 6.5, respectively. Apparent Km values of purified enzyme were 3.2 and 0.6mM for glycine and taurine, respectively. The Km value for choloyl-CoA was 50 microM for the glycine-dependent activity and 87 microM for the taurine-dependent activity. Bile acid derivatives and cholesterol had an inhibitory effect on both glycine- and taurine-dependent activity in vitro; on the other hand, the reaction was stimulated by the addition of glutathione, EDTA and L-cysteine. Amino acid substrate specificity was restricted to glycine, taurine, beta-alanine and D-alpha-alanine. As well as choloyl-CoA, its deoxy derivatives were also good substrates for the enzyme.

[Centro-median thalamotomy for central pain following stroke --its effectiveness and limits]

Centro-median thalamotomy was performed on 18 patients with central pain caused by cerebrovascular disease. Fourteen were males and four were females. Clinical diagnoses were thalamic pain in 17 cases including cheiro-orale syndrome in one case and phantom limb pain in one case. CT scans were performed on six recent cases. Four cases had a small low density sera in the thalamus. The other two cases had no remarkable findings. The target was 7.5-11.0 nm posterior to the middle point of the intercommissural line, 1.0 mm below-2.0 mm above that line and 5.5-10.0 mm from the midline. Unilateral lesion was made on 15 cases. Postoperatively, five cases had almost completely relief of pain and four cases had partial improvement. The duration of pain relief was, however, less than two months in four cases, and between three and seven months in four cases. One case had a pain free period for seven months. But, then, severe dysesthesia appeared. Six cases had no pain relief by unilateral lesion. Two cases had no pain relief by bilateral lesions. In the remaining case, unilateral lesion was effective for six months. Then lesion of opposite side was made, but the result was unsatisfactory. The durations from the onset of apoplectic attack to the occurrence of pain were between four months and three years in ten effective cases, and within three months in six among eight failed cases. Many surgical and medical treatments have been attempted for central pain. However, ideal method is still not appeared. Centro-median thalamotomy was effective for 56% of the patients with central pain. But in most of the cases, the duration of pain relief is about a half year at the longest. And may be, this is the limit of effectiveness of centro-median thalamotomy for central pain.

[Trigeminal neuralgia and hemifacial spasm caused by the compression of tortuous vertebro-basilar system--a case report (author's transl)]

A 63-year-old man was admitted to our clinic on August 14, 1980 with the chief compliant of left-sided intermittent facial pain. He had been suffering from twitching of the left facial muscles since 1972. During two years before admission, severe pain of the left face, starting in the left upper jaw and radiating to the left periorbital region, occurred intermittently. The pain aggravated by eating, talking and face-washing, gradually worsened and he became unable to take meals. On admission, he was alert. No sensory disturbance was seen. Muscle twitching was seen in the left orbicularis oculi, orbicularis oris and sometimes in the platysma. Mild facial palsy was recognized on the left side and other cranial nerves were intact. Computed tomogram with contrast enhancement revealed shift of the basilar artery to the left side. Markedly enlarged and tortuous vertebrobasilar system kinking at the left cerebello-pontine angle, was seen on the left vertebral angiogram. This tortuous vertebrobasilar system was presumed to be the cause of the trigeminal neuralgia and hemifacial spasm. The neuralgia disappeared after a controlled thermocoagulation of the left Gesserian ganglion, and the frequency of hemifacial spasm was reduced too. He was discharged with mild hemifacial spasm. The combination of trigeminal neuralgia and hemifacial spasm caused by direct compression of tortuous vertebro-basilar system on the nerve roots is rare. A case was reported and the literature were reviewed.

[Electrical activity of the dorsal hippocampus during DRL learning in the rabbit (author's transl)]

The change of electrical activity of the dorsal hippocampus during differential reinforcement of low rate (DRL) learning was examined in six rabbits. Bipolar electrodes were implanted stereotaxically into the dorsal hippocampus (3 mm posterior to bregma, 4-4.5 mm lateral and 7-7.5 mm ventral from bregma). After completion of continuous reinforcement learning, the animals learned DRL on a 10 sec. schedule. Rhythmic theta waves (6-8 Hz, 0.6-1.5 mV) were predominant in the early sessions of the DRL schedule. With further sessions, regular theta waves decreased and desynchronized waves or slightly irregular theta waves increased especially during the 10 second waiting period. Contrary to the report of Bennett et al., synchronized waves were always seen from 1-2 sec. before lever-press until completing of lever-press. Moreover, these preceding synchronized waves became more pronounced and of higher frequencies (8-10 Hz.) as learning proceeded. These high frequency regular waves (alpha-bursts) were seen in 5.6-35.8% of reinforced lever-press in the 10th session, and 79.5-93.8% in the 60th session. Alpha bursts were sometimes seen after 8-9 sec. waiting in the later sessions, but never seen within five secs.. During the extinction of DRL learning, the occurrence rate of alpha-bursts on adequate but non-rewarded lever-pressing decreased. These results cannot be explained satisfactorily in terms of an association between synchronized waves and voluntary movement. Frequency increase was seen when rabbits expected reinforcement after waiting for about 10 sec. or more. These results indicate that frequency increase of hippocampal synchronized waves is seen in association with higher central processing, most likely with memory.