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K Kamada

Publications and source records attributed to K Kamada.

At least 73 records · Page 4Linked to original sources
PubMed1996

Structure of a replication-terminator protein complexed with DNA.

The crystal structure of the Escherichia coli replication-terminator protein (Tus) bound to terminus-site (Ter) DNA has been determined at 2.7 A resolution. The Tus protein folds into a previously undescribed architecture divided into two domains by a central basic cleft. This cleft accommodates locally deformed B-form Ter DNA and makes extensive contacts with the major groove, mainly through two interdomain beta-strands. The unusual structural features of this complex may explain how the replication fork is halted in only one direction.

Amino Acid Sequence↗
PubMed1996

Crystallization and preliminary X-ray analysis of the Escherichia coli replication terminator protein complexed with DNA.

Crystals of the Escherichia coli replication terminator protein (Tus) complexed with its binding site DNA were obtained by a microdialysis method using PEG 4000. They belong to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2 with the unit cell parameter: a = 68.1 A, c = 230.7 A and contain one protein-DNA complex in an asymmetric unit. The native data set has been collected to 2.7 A resolution.

Bacterial Proteins↗
PubMed1996

Characteristics of intracranial aneurysms associated with moyamoya disease. A review of 111 cases.

A retrospective analysis of 111 patients with aneurysms associated with Moyamoya disease is presented. The subjects comprised of our 12 cases and 99 other well-documented cases. These 111 cases had 131 aneurysms. There were 48 males and 63 females. The average age was 40.3 years. The clinical manifestations were intracranial haemorrhage in 99 cases (89%), and ischaemic events in 9 cases (8%), but no mention was made of these in the last three cases (2%). The Hunt and Kosnik grades were grade 1 in 8%, grade 2 in 23%, grade 3 in 31%, grade 4 in 35%, and grade 5 in 3%. Of the 131 aneurysms, 73 (56%) were found distributed around the circle of Willis, 24 (18%) in the basal ganglia, 29 (22%) on collateral vessels, and 5 (4%) on other vessels. Forty-six percent of the cases were treated surgically, 51% conservatively, and 3% by endovascular procedures. The surgical procedures for the aneurysms were; neck clipping in 49%, aneurysmectomy in 18%, wrapping of the aneurysm in 11%, coating or cautery of the aneurysm in 7%, and revascularization only in 11%. The outcomes were Glasgow Outcome Scale 1 in 30%, 2 in 22%, 3 in 11%, 4 in 1%, and 5 in 25%. The main reasons for the unfavourable outcome were initial poor clinical grade and rebleeding. Follow-up angiography of 25 aneurysms demonstrated that all aneurysms in the basal ganglia or on the collateral vessels disappeared. We recommend surgical intervention for aneurysms associated with Moyamoya disease to prevent rupture or rebleeding, especially for aneurysms around the circle of Willis. However, direct surgery is not recommended for aneurysms found in the basal ganglia or on the collateral vessels.

Adolescent↗
PubMed1996

Intra-operative monitoring by facial electromyographic responses during microvascular decompressive surgery for hemifacial spasm.

The facial electromyographic response was monitored intraoperatively in 40 patients with hemifacial spasm who were operated on by microvascular decompression of the facial nerve. All 40 patients showed an abnormal facial electromyographic response (lateral spread response) with a latency of about 10 msec after stimulation. The abnormal response resolved before decompression in 22, resolved immediately with decompression in 16, and failed to resolve in two. Of the 38 patients in whom the abnormal response disappeared during surgery, 36 were postoperatively free from hemifacial spasm and two had mild hemifacial spasm. The two patients in whom the lateral spread response did not disappear during surgery showed persistent hemifacial spasm. In conclusion. Disappearance of the lateral spread response during surgery correlated with the absence of hemifacial spasm in the early postoperative period. The prognosis of hemifacial spasm was good in cases in whom the lateral spread response disappeared. Therefore, the authors think that intra-operative facial electromyography is very useful in assessing the efficacy of microvascular decompression and in predicting the prognosis of hemifacial spasm.

Adult↗
PubMed1996

Clinical features of the haemorrhage type moyamoya disease based on 31 cases.

We evaluated and analysed our own 31 cases of the haemorrhagic type of moyamoya disease to clarify the clinical features of this disease. The cases were divided into three groups. Group A consisted of 12 cases with aneurysms. Aneurysms on the circle of Willis were treated as ordinary saccular aneurysms. Group B consisted of 14 cases with intracerebral haemorrhage (ICH) without aneurysms. These were managed almost as spontaneous ICH. Group C consisted of 5 cases with intraventricular haemorrhage (IVH) without aneurysms or ICH. Twenty-two surgical procedures for aneurysms, ICH and IVH were done in 19 cases (62%). Nineteen procedures for preventing future strokes were undertaken in 11 cases (35%). The overall initial outcome was excellent in 12 cases (39%), good in 7 cases (23%), poor in 7 cases (23%), and death in 5 cases (15%). During the follow-up period (mean: 6.5 years), rebleeding occurred in two cases (8%), and ischaemic attacks in two cases (8%). The rate of rebleeding or ischaemic attacks was 1.19% per patient-year during the follow-up period. There was no ischaemic or rebleeding episode in cases treated by STA-MCA bypass with encephalomyosynagiosis (EMS) during the follow-up period. Management of the primary haemorrhage should be according to the clinical condition, type of haemorrhage, and source of haemorrhage. When the patient needs to undergo revascularization surgery to prevent future strokes, we recommend STA-MCA bypass with EMS instead of encephaloduro-arteriosynangiosis (EDAS).

Adult↗
PubMed1996

Shear bond strengths of three resin cements used with three adhesive primers for metal.

This study compared the durability and shear bond strengths of combinations of three adhesive primers and three resin cements bonded to silver-palladium-copper-gold (Ag-Pd-Cu-Au) and cobalt-chromium (Co-Cr) alloys. The adhesive luting cements Imperva Dual, Panavia 21, and Super-Bond C&B and the adhesive primers Metal Primer material, V-Primer material, and Cesead Opaque Primer material were used. The application of Metal Primer material was effective in improving the shear bond strengths between each of the three resin cements and Ag-Pd-Cu-Au alloy compared with nonprimed specimens. Co-Cr alloy primed with Cesead Opaque Primer, followed by cementation with Imperva Dual or Super-Bond C&B luting cements yielded the strongest shear bond strengths after 50,000 thermocycles, and Panavia 21 cement did not reveal any significant differences in bond strengths between nonprimed specimens and those primed with Cesead Opaque Primer at all thermocycles.

Adhesives↗
PubMed1996

Proton magnetic resonance spectroscopy in patients with glial tumors: a multicenter study.

The authors represent a cooperative group of 15 institutions that examined the feasibility of using metabolic features observed in vivo with 1H-magnetic resonance (MR) spectroscopy to characterize brain tumors of the glial type. The institutions provided blinded, centralized MR spectroscopy data processing long with independent central review of MR spectroscopy voxel placement, composition and contamination by brain, histopathological typing using current World Health Organization criteria, and clinical data. Proton 1H-MR spectroscopy was performed using a spin-echo technique to obtain spectra from 8-cc voxels in the tumor and when feasible in the contralateral brain. Eighty-six cases were assessable, 41 of which had contralateral brain spectra. Glial tumors had significantly elevated intensities of choline signals, decreased intensities of creatine signals, and decreased intensities of N-acetylaspartate compared to brain. Choline signal intensities were highest in astrocytomas and anaplastic astrocytomas, and creatine signal intensities were lowest in glioblastomas. However, whether expressed relative to brain or as intratumoral ratios, these metabolic characteristics exhibited large variations within each subtype of glial tumor. The resulting overlaps precluded diagnostic accuracy in the distinction of low-and high-grade tumors. Although the extent of contamination of the 1H-MR spectroscopy voxel by brain had a marked effect on metabolite concentrations and ratios, selection of cases with minimal contamination did not reduce these overlaps. Thus, each type and grade of tumor is a metabolically hetero-geneous group. Lactate occurred infrequently and in all grades. Mobile lipids, on the other hand, occurred in 41% of high-grade tumors with higher mean amounts found in glioblastomas. This result, coupled with the recent demonstration that intratumoral mobile lipids correlate with microscopic tumor cell necrosis, leads to the hypothesis that mobile lipids observed in vivo in 1H-MR spectroscopy may correlate independently with prognosis of individual patients.

Adolescent↗
PubMed1996

[Posterior fossa dural arteriovenous fistula with progressive disorder of cerebellar circulation; case report].

A rare case of posterior fossa dural arteriovenous fistula with cerebellar circulation disorder is reported. A 64-year-old male was admitted to a hospital with complaints of nausea, vertigo and mild headache. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed cerebellar infarction. Then, he was sent to our hospital. He had complaints of cerebellar signs and nystagmus. Cerebral angiography showed dural AVF of the posterior fossa and occlusion of the left transverse-sigmoid sinuses. Because his condition deteriorated, embolization of the left middle meningeal artery, ascending pharyngeal artery and occipital artery was performed selectively on August 18. Subsequently, isolation of dural AVF was performed on August 19. After the operation he improved and was able to walk with a stick. Controlled angiography revealed the disappearance of dural AVF. This case suggested that AV shunt is essential for the progression of venous infarction.

Arteriovenous Fistula↗
PubMed1996

[Sequential observations of brain edema with proton magnetic resonance imaging and spectroscopy].

The purpose of this study was to assess the relationship between morphological and metabolic changes in brain edema using proton magnetic resonance systems. The serial changes during the first 24 hours in the cold-injury trauma rat brain model were investigated by proton magnetic resonance imaging (1H MRI) and high-resolution proton MR spectroscopy (1H MRS). We also analyzed the efficacy of AVS 1,2-bis (nicotinamide)-propane which can scavenge free radicals to the edema in this experiment. The edema was developing extensively via the corpus callosum in ipsi- and contralateral hemispheres as shown by gradually increased signal intensity on 1H MRI. 1H MRS initially showed accumulation of acetate and lactate, and transient increasing of glutamine. After 24 hours, the increased glutamine decreased below the control, alanine increased, and N-acetyl asparatate decreased with the edema development. AVS-treatment significantly suppressed edema development, increases of lactate and alanine and decreases of N-acetyl asparatate. We suggest that the cold-induced lesion contains anaerobic glycolysis deterioration and results in severe brain tissue breakdown. AVS is proved valuable for the treatment of this edema lesion. Clinical 1H MRS showed prolonged lactate elevation and significant decreases of other metabolites in human ischemic stroke edema. In peritumoral edema, decreased N-acetyl asparatate gradually improved, and slightly elevated lactate disappeared after tumor removal. 1H MRS feasibly characterizes the ischemic and peritumoral edema and makes a quantitative analysis in human brain metabolism. We believe the combined 1H MRI and MRS study is a practical method to monitor the brain conditions and will make it easy and possible to find new therapeutic agents to some brain disorders.

Aged↗
PubMed1995

Increase in expression levels of interferon-inducible genes in senescent human diploid fibroblasts and in SV40-transformed human fibroblasts with extended lifespan.

The normal human fibroblast line, TIG-3 which senesces at around 80 population doubling levels (PDLs), expressed interferon (IFN)-inducible genes such as 6-16, 2', 5'-oligoadenylate synthetase (2,5-A) and HLA B7 near the end of the proliferative lifespan. Other normal fibroblast line such as MRC-5 also expressed IFN-inducible genes when senesced. Clones transformed with SV40 T-antigen, which extended their proliferative lifespan by about 20-30 PDLs, also expressed IFN-inducible genes during their extended life. Anti-IFN-beta antibodies added in culture medium repressed the expression of IFN-inducible gene in both normal senescent and life-extended SV40-transformed cells. IFN-beta repressed DNA synthesis in normal TIG-3 and induced IFN-inducible genes in both normal and SV40-transformed TIG-3. Conditioned medium recovered from life-extended SV40-transformed cells contained IFN-beta, but not IFN-alpha, IFN-gamma or TNF-alpha and possessed an activity that inhibited DNA synthesis of young TIG-3. Addition of anti-IFN-beta antibodies into the medium enhanced the serum-induced DNA synthesis of near senescent (91% lifespan completed) TIG-3, while it neither induced DNA synthesis in fully senescent TIG-3 nor extended the proliferative lifespan of TIG-3. These results suggest that normal and SV40-transformed human fibroblasts increase expression of IFN-beta with increasing proliferative age especially near the end of their lifespan resulting in induction of IFN-inducible genes and possibly in growth repression.

Cell Line↗
PubMed1995

Proton magnetic resonance spectroscopy (1H-MRS) for the evaluation of treatment of brain tumours.

We investigated metabolic changes in brain tumours following treatment, using proton magnetic resonance spectroscopy. In meningiomas, effective therapeutic embolisation led to an acute increase in lactate. In radiosensitive tumours such as malignant lymphoma, a decrease in lactate and in increase in N-acetyl-aspartate occurred after radiotherapy, which preceded changes observed on magnetic resonance imaging. On the other hand, no significant changes in spectral patterns were observed in malignant gliomas resistant to therapy. Tissue characterisation of brain tumours by spectral patterns on proton magnetic resonance spectroscopy remains controversial. However, we have shown it to be sensitive to metabolic changes following treatment, which may reflect the efficacy of the therapy.

Astrocytoma↗
PubMed1995

A comparison of water temperatures for thermocycling of metal-bonded resin specimens.

The thermocycling test to evaluate the bonding durability of the adhesive interface against water penetration and thermal stress is one of the most important studies before clinical application of metal-bonded resin systems is performed. Researchers have adopted various water temperatures for thermocycling adhesion specimens, which makes a direct comparison with thermocycling data attained by other researchers difficult. In this study tensile and shear bond strengths of metal-bonded resin specimens were measured after 20,000 thermocycles with the temperatures of the hot bath at 50 degrees C, 60 degrees C, and 70 degrees C. The results indicated that adhesive bonding strengths attained after thermocycling at 50 degrees C may be nearly comparable with those at 60 degrees C.

Analysis of Variance↗
PubMed1995

Alangionosides G-M: glycosides of megastigmane derivatives from the leaves of Alangium premnifolium.

Phytochemical investigation of the 1-BuOH-soluble fraction of the MeOH extract of Alangium premnifolium resulted in the isolation of ten megastigmane glycosides, of which, two, (6R,9R)-3-oxo-alpha-ionol apiofuranosylglucopyranoside and roseoside with (6S,9R)-blumeol A as an aglycone were known. The structures of the eight new compounds were determined by spectroscopic methods.

Cyclohexanes↗
PubMed1995

Serial changes in metabolism and histology in the cold-injury trauma rat brain model--proton magnetic resonance imaging and spectroscopy study.

The serial changes in metabolism and histology during the first 24 hours in the cold-injury trauma rat brain model were investigated by proton magnetic resonance (MR) imaging and high-resolution proton MR spectroscopy. Edema developed extensively via the corpus callosum in the ipsi- and contralateral hemispheres during observation as shown by gradually increased signal intensity on proton MR images. Proton MR spectroscopy showed increased levels of acetate (Ace), lactate (Lac), and glutamine (Glmi) 1 hour after lesion formation. The elevated Glmi level slightly decreased, the level of alanine (Ala) increased substantially, and that of N-acetyl-aspartate (NAA) decreased markedly after 24 hours. Increased Lac, Ace, and Ala might reflect anaerobic glycolysis associated with mitochondrial dysfunction, while decreased Glmi and NAA reveal brain tissue breakdown. The relationship between brain edema and tissue viability can be analyzed in detail using this simple traumatic model and MR techniques which will be useful in the development of therapeutic agents for brain injury.

Acetates↗
PubMed1995

[The mechanism of cardiorespiratory arrest due to subarachnoid hemorrhage].

This report describes the clinical course of patients with sudden cardiorespiratory arrest (CRA) due to subarachnoid hemorrhage (SAH). We have seen fifteen patients of SAH that presented initially as CRA. All of them were diagnosed as SAH by CT scan. The patients were divided into two groups; one group (early DOA group) included 11 patients, who had been recognized as CRA within 60 minutes from the onset of SAH, the other group (late DOA group) consisted of 4 patients, who developed CRA more than 60 minutes after the initial onset. The major mechanism leading to delayed CRA in the late DOA group appeared to have been from brain stem herniation, but another mechanism appeared to be involved in sudden CRA in the early DOA group. Sixty percent of our patients with CRA due to SAH had a low serum potassium concentration, though hypokalemia was observed in only 4 out of 100 patients with CRA due to diseases other than SAH. These facts suggest that sympathetic hyperstimulation might result not only from stress but also from a disorder of the central autonomic nervous system. We speculate that the mechanism leading to early CRA after SAH appears to result from a disorder of the central autonomic nerve system.

Aged↗
PubMed1995

[Proton MR spectroscopy in patients with unilateral temporal lobe epilepsy].

The authors assessed proton magnetic resonance spectroscopy (1H-MRS) in patients with unilateral refractory temporal bole epilepsy. The subjects consisted of 20 patients (those with brain tumors, trauma, malformations or definite organic lesions were excluded) and 10 normal volunteers. 1H-MRS and MRI were performed using a 1.5 tesla machine. 1H-MRS was achieved using point-resolved spectroscopy (PRESS) or the stimulated echo acquisition mode (STEAM), and a 3 x 3 x 3 cm volume of interest was positioned at the hippocampus. N-Acetyl-aspartate (NAA) and choline-containing substance (Cho) signals were evaluated. The results showed decreased NAA and elevated Cho or asymmetry of both NAA and Cho in the epileptogenic focus in 19/20 cases. The reductions in NAA presumably reflect neuronal loss, while the elevation of Cho probably represents membrane break down within the lesion. These abnormalities were observed in 19/20 cases (95%), whereas abnormal magnetic resonance imaging was detected in only 6/20 (30%) of the patients. Thus, 1H-MRS appears to be a useful, non-invasive modality for evaluating metabolic changes in epileptogenic foci, and these metabolic changes can serve as a more sensitive indicator than magnetic resonance imaging.

Adolescent↗
PubMed1995

[Penetrating injury of the head, neck and chest by a nail-gun: a case report].

A very rare case of directly penetrating injury of the head, neck and chest caused by a nail-gun was reported. A 56-year-old male was admitted to our critical care center due to chest injury. On admission, he showed numbness of the hand & leg, left hemiparesis and hypalgesia. Physical examination disclosed three nails on the left anterior chest, but other wounds or nails were not found. Chest films showed three nails penetrating the lung without reaching the heart, but other nails were found by skull and neck films. One nail had penetrated the cervical canal at the C1 level through the posterolateral cervical region. Two other nails were demonstrated at the right temporal and the left frontal region, Computed tomography revealed no massive cerebral hemorrhage and cerebral angiography showed no extravasation and no passage through main vessels. Emergency surgery was performed uneventfully and the nails in the chest, neck and head were totally removed. He was discharged one month after surgery. Some injuries caused by a nail-gun have been reported in the world literature but in Japan this multiple injury case was the first reported. Since nail-gun injuries can cause multiple damage, systemic X-ray examination was very important.

Cervical Vertebrae↗