First Direct Measurement of (12)C((12)C,n)(23)Mg at Stellar Energies.

Neutrons produced by the carbon fusion reaction (12)C((12)C,n)(23)Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction (12)C((12)C,p)(23)Na. The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate, we find that (12)C((12)C,n)(23)Mg is crucial to the production of Na and Al in pop-III pair instability supernovae. It also plays a nonnegligible role in the production of weak s-process elements, as well as in the production of the important galactic γ-ray emitter (60)Fe.

Measurement of the two-halo neutron transfer reaction (1)H((11)Li, (9)Li)(3)H at 3A MeV.

The p((11)Li, (9)Li)t reaction has been studied for the first time at an incident energy of 3A MeV at the new ISAC-2 facility at TRIUMF. An active target detector MAYA, built at GANIL, was used for the measurement. The differential cross sections have been determined for transitions to the (9)Li ground and first excited states in a wide range of scattering angles. Multistep transfer calculations using different (11)Li model wave functions show that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.

New determination of the astrophysical S factor SE1 of the 12C(alpha,gamma)16O reaction.

A new measurement of the beta-delayed alpha decay of 16N has been performed using a set of high efficiency ionization chambers. Sources were made by implantation of a 16N beam, yielding very clean alpha spectra down to energies as low as 400 keV. Our data are in good agreement with earlier results. For the S factor S(E1), we obtain a value of 74 +/- 21 keV b. In spite of improvements in the measurement, the error in S(E1) remains relatively large because of the correlations among the fit parameters and the uncertainties inherent to the extrapolation.

Vanishing N = 20 shell gap: study of excited states in (27,28)Ne.

This Letter reports on the (1)H((28)Ne, (28)Ne) and (1)H((28)Ne, (27)Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2(+) excited state of (28)Ne, and using the previously determined BE(2) value, the neutron quadrupole transition matrix element has been calculated to be M(n)=13.8 +/- 3.7 fm(2). In the neutron knockout reaction, two low-lying excited states were populated in (27)Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.

Anomalously hindered E2 strength B(E2;2+(1)-->0+) in 16C.

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

[A new apparatus using the Micro Ultra-Sonic Aspirator (MUSA) system for microneurosurgery].

Matsumoto was the first to present the NIIC UltraSonic Aspirator for CT guided stereotactic aspiration of intracerebral hematoma. Based on the NIIC Aspirator, the authors have developed a useful tool for microsurgery by adapting conventional ultrasonic aspirators. This was done by making the aspirator lighter and more handy for use during microsurgical procedures. A newly devised apparatus using the Micro Ultra-Sonic Aspirator (MUSA) was applied clinically to surgical treatment for brain tumors, arterio-venous malformations (AVMs) and intracerebral hematomas. Using the MUSA system, it became easier to remove successfully tumorous mass and the nidus of AVM, because it minimized the risk of injury to the normal structures such as the surrounding brain tissue, vascular systems and the cranial nerves.

[Identification of location of electrode tip during percutaneous retrogasserian glycerol injection (PRGI) with blink reflexes elicited by direct stimulation of trigeminal complex (DBR)].

In order to identify the location of the electrode tip during percutaneous retrogasserian glycerol injection (PRGI), the blink reflex (DBR) following direct stimulation of the trigeminal complex (the gasserian ganglion, trigeminal rootlets, or the 3rd division of the trigeminal nerve) was obtained from 6 patients with trigeminal neuralgia. 1) The waveform of the DBR was very similar to that of the blink reflex (BR) elicited by percutaneous stimulation of the 1st division of the trigeminal nerve. However, the latency of early reflex (R1) as well as late reflex (R2) of the DBR was approximately 2 msec shorter than that of the conventional BR. 2) When the electrode tip was introduced into the gasserian ganglion, the DBR showed the largest response under the same recording condition, whereas the DBR was not recorded when the tip of the electrode was placed into either the arachnoid space or the subdural space. The each DBR response, however, showed the same configuration when the electrode tip was situated at the territory of the 1st, 2nd or 3rd division of the trigeminal nerve within the gasserian ganglion or the trigeminal cistern. 3) The DBR always appeared under the anesthesia with the intravenous administration of 10 mg diazepam and 30 mg pentazocine. 4) Based on the present study, the DBR proved to be an usuful parameter in determining whether the electrode tip is introduced into the trigeminal complex or not, particularly in the case of patients having no reliable sensory response to electrical stimulation.

[CT-guided stereotactic brachytherapy in deep-seated malignant gliomas--interstitial irradiation by double-catheter after-loading method].

CT-guided stereotactic brachytherapy has been performed for the deep-seated malignant gliomas using the double-catheter after-loading method. The catheter system consists of two coaxial polyethylene tubes with closed tips. The outer catheter is 3.0 mm in outer diameter and 2.4 mm in inner diameter. The inner catheter is 2.0 mm in outside diameter and 1.4 mm in inside diameter, and contains the radioactive sources. Localization of the target volume is determined by the preoperative findings of computed tomography (CT), magnetic resonance imaging (MRI), and cerebral angiography. Dosimetry and dose planning are so finalized for the target volume as to be irradiated interstitially more than tumoricidal dose. After stereotactic biopsy of the deep-seated brain tumors, stereotactic implantation of the outer catheters is performed using Iseki Stereotactic System in the CT room. Burr holes had been previously opened in the operating room. The inner catheters containing nonradioactive sources (dummy sources) are inserted, and skull X-p is taken to confirm the position of the dummy sources, and to calculate the dosimetry by computer. The inner catheters are replaced with catheters containing radioactive sources (226Ra) in the irradiation room. 226Ra sources deliver at least 500 rads/day (approximately 20 rads/hr) to the target volume as interstitial irradiation. Two patients of malignant gliomas treated with this procedure were shown as representative cases. These patients underwent CT-guided stereotactic brachytherapy as "boost" combined with conventional external irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Short latency somatosensory-evoked potentials--direct recording from the human midbrain and thalamus.

Short latency somatosensory-evoked potentials were recorded from the human thalamus and the midbrain during stereotactic operations. Several subcomponents were recognized on the peak of N18. These were recorded with maximal amplitude at the border between the caudal portion of the thalamus and the rostral midbrain. Two positive-negative responses, not previously shown, were observed between P14 and N18. These responses were prominent in the rostral midbrain. These findings indicate that the ascending phase of N18, and the N18 itself, are the compound potential generated in the mesodiencephalic junction.

[A new treatment of hypertensive intracerebral hematoma--a follow-up study on 46 patients with hematoma treated by CT guided stereotactic method].

During the last 2 years, 46 cases of hypertensive intracerebral hemorrhage in the basal ganglia were treated by CT guided stereotactic aspiration and their outcome was evaluated in terms of the rate of hematoma removal, the change of consciousness level and the recovery of motor and sensory functions. They are aged from 45 to 79 years old, the average 56, and aspirated 1 to 24 days after the onset, two third of them being within 1 week. The whole procedure was done in the CT room under direct CT guidance and by one trial. In putaminal type hemorrhage, the removed hematoma volumes ranged from 9 to 48 ml, average being 23.7 ml, in thalamic type from 5 to 29 ml, average being 15.5 ml. The average rate of removal was 81.1% in 30 cases within 1 week. In most cases, preoperative consciousness was not severely disturbed, in putaminal type, 19 were alert or confused, 4 somnolent, 5 stuperous and in thalamic type, 6, 6, 3 respectively and 2 were semicomatous, one of them had herniation sign. In putaminal type all but 2 cases recovered to alert or confused state, the first one had postoperative bleeding and the other was already apallic preoperatively. In thalamic type, we lost 3 cases, 2 by gastrointestinal bleeding and 1 DIC, by rehemorrhage 2 months after the operation. All but one who was semicomatous preoperatively recovered to alertness. In motor function, some cases of the putaminal bleeding with intact internal capsule remained hemiplegic. On the other hand, most of the cases with partial destruction of the internal capsule on CT recovered well in both types of hematoma.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance probability mapping of brain electrical activity--its problem and specified z-statistic mapping].

Significance probability mapping (SPM) of brain electrical activity first described by Duffy et al. is useful tool for studying functional aspects of brain disease. Z-statistic SPM is able to identify the area of brain electrical activity deviated with statistic significance from the control group. The problem of this method is, however, that the nature of deviation, i.e., whether it is increase or decrease of electrical activity, can not be displayed. From this point of view, we attempted to use modified z-statistic method. Statistically deviated region and its nature can be clearly displayed on the same picture by analyzing EEG with this method. This method can be applied to SPM of evoked potentials. SPM is not yet complete method for the assessment of brain electrical activity, but there is much room for adopting other statistic method that is more suitable for the aim of the study. Functional aspects of the brain will be more readily clarified by the use of modified SPM and by combination with findings of CT scan, NMR and PET that can give morphological and metabolic information.

[Ascending limb of the N20 component of somatosensory evoked potential--an analysis on direct recording from the human midbrain].

Somatosensory evoked potential elicited by median nerve stimulation at the wrist was recorded from five loci on the trajectory of stereotactic rostral mensencephalic reticulotomy. Four distinct positive waves followed by one negative wave, the peak latency being 16.3 msec, were recorded from the rostral midbrain reticular formation near the medial lemniscus. The four positive waves were named as I, II, III, and IV respectively. Peak latency of these positive waves was 12.6, 13.7, 14.7 and 15.8 msec respectively. The first two positive waves (I, II) corresponded to P13 and P15 recorded over the scalp. The other two positive waves (III, IV) changed their polarity to negative at the level of the ventral thalamus and formed the ascending limb of N20 recorded over the scalp. N16 was most prominent at the level of nucleus ventrocaudalis externus. These findings suggest that the ascending limb of N20 is composed of at least three components, wave III, IV, and N16. The present report is compatible with the investigations by Abbruzzese et al.2) and Eisen et al.11) that there are several distinct dipoles between P15 and N20 of somatosensory evoked potential in man.

Long-term follow-up study of rostral mesencephalic reticulotomy for pain relief--report of 34 cases.

A long-term follow-up study of rostral mesencephalic reticulotomy (RMR) for pain relief is presented. 34 patients (24 males and 10 females) were operated. Ages ranged from 18 to 65 years. The follow-up period was 1-70 months. The overall effectiveness of RMR showed good relief of pain in 23 patients (67%). The study of effectiveness of RMR according to type of pain showed good relief of pain in 5 out of 6 patients (83%) with nondenervation pain, whereas satisfactory pain relief was obtained in 18 out of 28 patients (64%) with denervation pain.

[An assessment of outcome prediction in patients with severe brain damage with auditory brainstem response and blink reflex].

Results of auditory brainstem response (ABR) and electrically elicited blink reflex (BR) recorded from 43 patients with severe brain damage within three days after the onset of illness were analyzed to assess the prognostic value of ABR and BR with respect to patient outcome evaluated by the criteria proposed by Jennett and Bond. It was possible to recognize, in recordings obtained from patients with severe brain damage, three basic patterns of BR as well as five patterns of ABR within three days after the onset. Three basic patterns of BR were composed of Type I, which closely approximated the BR of normal subjects except for moderately prolonged latency of R2, Type II, which indicated absence of bilateral R2 activities, and Type III, which showed absence of R1 as well as bilateral R2. ABRs were graded, in increasing order of abnormality, from Type I to Type V. Type I was almost normal pattern from wave I to wave V. Type II indicated prolonged latency or markedly reduced amplitude of waves IV and V. Type III showed absence of waves IV and V. Type IV had only wave I. Type V indicated absence of all waves. BR abnormalities significantly proved useful in predicting vital prognosis of the comatose patients with supratentorial lesion. In patients who had Type II of BR, additional studies of ABR enhanced the reliability of prediction of functional prognosis. On the other hand, ABR was recognized as stronger basis for predicting outcome in patients with infratentorial lesion. All patients with Type IV or Type V of ABR were expired within one month after the onset.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of anticonvulsant-induced bone changes by a microdensitometric method].

The effect of long-term anticonvulsants on bone change was evaluated by microdensitometric method (MD method) in 221 outpatients of Neurological Institute Tokyo Women's Medical College. Laboratory findings including serum Ca, P, Al-p were compared with severity of bone change. Following results were obtained; In 221 patients, 159 cases (72%) were normal, 31 cases (14%) were in the initial stage of abnormality, 23 cases (10%) in grade I, 7 cases (3%) in grade II and one case (1%) in grade III of abnormality. Incidence of abnormality was high in the age of 26-35 years old and in the age over 56 years old. Total dose, serum concentration of diphenylhydantoin (DPH) as well as phenobarbital (PB) and also duration of administration of PB correlated positively with severity of bone change. Duration of administration of DPH and valproic acid (VPA), total dose and serum concentration of VPA did not correlate with severity of bone change. Serum Ca correlated with severity of bone change, but P and Al-p did not correlate with severity of bone change. Pattern of bone change was estimated by two parameters of MD method (MCI and GSmax). Results showed that most of the osteopathy (grade I-III by MD method) fell into osteoporotic type. Based on these results, it is suggested that roentgenologic and biochemical supervision of the patients is required during long-term anticonvulsant therapy.

[A new apparatus and stereotactic method for percutaneous high cervical cordotomy].

The authors devised a stereotactic apparatus for percutaneous cordotomy based on the experience of 191 percutaneous high cervical cordotomies on 150 patients suffering from intractable pain. This apparatus has two major components. One is a head and neck holder and the other is a guide and marker system. The head and neck holder contains fixed neck holder and head holder which can be movable in vertical direction. Using these holders, the operator can keep the patient's neck in neutral position. The marker system contains two markers of origin and a 10mm scale which indicates center line as well. The guide system, stereotactically designed, is movable in three direction and acrylic guide groove is attached. The guide needle for percutaneous cordotomy is inserted along the guide groove. The guide and marker system can be attached in both sides of the head and neck holder, therefore, the operator can insert the needle in both sides of the patient. This apparatus makes it possible to locate the target stereotactically for percutaneous cordotomy, since location of the inserted needle can be determined with the aid of cervical X-ray, even if there is no image intensifier of TV display screen available. Therefore it can be possible to reduce the X-ray exposure of the patient.

CT-guided stereotactic surgery for evacuation of hypertensive intracerebral hematoma.

During the last 3 years, 46 cases of hypertensive intracerebral hemorrhage were treated by CT-guided stereotactic surgery. Our present report is concerned with the evaluation of this procedure in the treatment of hypertensive intracerebral hematoma, in terms of the rate of aspirated hematoma and follow-up study of patients. It is difficult to draw any definite conclusion about the operative indications. CT-guided stereotactic aspiration, however, can be evaluated as a less invasive and more definitive treatment of intracerebral hematoma in the basal ganglia and thalamus.