Search PubMed⌕ Search

Biomedical subjects

S Ban

Publications and source records attributed to S Ban.

At least 109 records · Page 6Linked to original sources
PubMed1992

Moyamoya disease progressing from unilateral to bilateral involvement--case report.

A 2-year-old boy with unilateral moyamoya disease demonstrated progression to the bilateral condition 1 year later. Previous reports of progression from unilateral to bilateral moyamoya disease showed that all patients were children or relatively young, and developed ischemic symptoms as the initial manifestation. These findings suggest that a considerable proportion of unilateral pediatric cases are in the initial stage of moyamoya disease and will progress to the contralateral side in the future.

Carotid Arteries↗
PubMed1992

Phase transformation of octacalcium phosphate in vivo and in vitro.

Octacalcium phosphate (OCP) was implanted in both thigh muscle pouches of ddY mice for 3 weeks, and was soaked in a simulated body fluid (SBF) and 1% NaCl solution maintained at 37 degrees C for 1 day, 1 week and 3 weeks. After implantation or soaking, the specimens were characterized by scanning electron microscopic analyses, X-ray diffractometry, and infrared absorption spectroscopy. X-ray diffraction study showed that OCP had been completely transformed to apatite with low crystallinity such as the mouse's femur after a 3-week implantation in the mouse body, and an apatic crystal was formed after soaking in the NaCl solution. The IR absorption spectra revealed that CO3 was incorporated in the apatite formed from OCP in both the mouse body and the NaCl solution, while OCP changed little after soaking in the SBF. It seems that the magnesium ion retards the transformation of OCP to apatite.

Animals↗
PubMed1992

[A case of citrullinemia associated with isolated ACTH deficiency, rapidly developing coma].

We report a 41-year-old male of citrullinemia associated with argininosuccinate acid synthetase deficiency. He was admitted to the Hitachi General Hospital because of finger tremor, restlessness and urinary incontinence. He had short stature and a poor appetite. Laboratory evaluation was summarized as follows: mild hypoglycemia, low plasma cortisol levels, delayed response of 17-OHCS and 17-KS to ACTH administration in urine, and delayed response of plasma ACTH level to insulin administration. In this case, ACTH deficiency is estimated to be a dysfunction of the hypothalamus. Replacement therapy of hydrocortisone improved his symptoms. He was readmitted to the hospital because of delirium and confusion, two weeks after the hydrocortisone administration. At that time, he had flapping tremor. Laboratory examination revealed hyperammonemia (NH3: 231 micrograms/dl) and mild elevation of GOT and GPT. Serum and urinary amino acid determination showed marked elevation of citrulline (478.1 nmol/ml in serum, 4681.2 mumol/day in urine). Lactulose administration, low protein diet and plasmapheresis were started, but he went into a coma. Without any improvement, he died on the 29th hospital day. Autopsy examination of the liver disclosed fatty change. Adrenal cortex depicted severe atrophy. Biochemical analysis of urea cycle enzymes of the liver and kidney showed decreased activity of argininosuccinate synthetase (liver: 0.0022 U/mg protein, 5% of that normal liver, kidney: 0.003 IU/mg protein, 20% of that in normal kidney). Citrullinemia associated with ACTH deficiency have not reported in the literature. It may be presumed that ACTH deficiency is concerned with the delayed onset of hyperammonemia. The relation between citrullinemia and endocrinological abnormalities is also discussed.

Adrenal Cortex↗
PubMed1992

X-ray induction of micronuclei in human lymphocyte subpopulations differentiated by immunoperoxidase staining.

In this study we sought to confirm the radiosensitivity of human peripheral blood lymphocyte subpopulations using a micronucleus assay. Mononucleated cells isolated from peripheral blood were irradiated with X rays. After being cultured for 3 days, cells were fixed and stained using the immunoperoxidase staining technique. Lymphocyte subpopulations were characterized by means of the monoclonal antibodies Leu4 (CD3), Leu2a (CD8) and Leu19 (CD56). Dose-response curves were obtained by scoring the number of micronuclei in binucleated cells that reacted with a specific antibody and were then stained. The dose response of CD8+ (suppressor/cytotoxic) cells was quite similar to that of CD3+ (pan T) cells. In comparison, CD56+ (natural killer) cells were significantly less sensitive, although scorable binucleated CD56+ cells made up less than 4% of the total number of binucleated cells.

Adult↗
PubMed1992

Sacrococcygeal chordoma with a malignant spindle cell component. A report of two autopsy cases with a review of the literature.

Two autopsy cases of sacrococcygeal chordoma which showed sarcomatous components in the primary and metastatic tumors are reported. Case 1 was a 48-year-old female who died 9 years after the development of the initial symptoms. Autopsy findings showed metastatic tumors consisted of malignant tumor cells similar to fibrosarcoma and osteosarcoma. Case 2 was a 63-year-old male who died 11 years after the development of the initial symptom. At autopsy only sarcomatous tumors resembling malignant fibrous histiocytoma (MFH) were observed in the metastatic lesions. Both cases were treated with irradiation. It is suggested that the appearance of sarcomatous tumor in current two cases of chordoma might be due to the phenomenon of tumor progression closely associated with irradiation therapy. These two cases can be categorized as "chordoma with a malignant spindle cell component" in a sense that highly malignant sarcomatous components existed in conjunction with chordoma in the primary tumors.

Autopsy↗
PubMed1991

Malignant meningioma with repeated multiple recurrence. A case report.

A case of malignant meningioma with repeated multiple recurrence was reported. A 22 year-old male first underwent the total removal of left parieto-occipital convexity meningioma in 1965. Although he had lived an uneventful life after the operation, he recognized motor weakness of the left lower limb in April 1985 when he was 41 years old and CT revealed a large tumor in the parieto-occipital parasagittal region. He underwent the total removal of the tumor and cranioplasty on May 23, 1985. After the second operation, repeated recurrence of multiple tumors was seen, which were in the frontal, parietal and occipital convexities, parasagittal regions and falx. He underwent further operations on January 23, 1986, December 11, 1986, March 30, 1987 and July 20, 1987 in addition to the first and second ones. Histological study on every operation indicated malignant meningioma with mitosis, hypercellularity and necrosis. Though radiotherapy (56 Gy whole brain irradiation) was conducted after the sixth operation, multiple tumors recurred and clinical symptoms and signs deteriorated gradually and he finally died September 9, 1989. In malignant meningioma such as our case, early aggressive radiotherapy and chemotherapy should be considered besides radical operations.

Adult↗
PubMed1991

Electrochemical corrosion behaviour of hydroxyapatite-glass-titanium composite.

To determine whether hydroxyapatite(HA)-containing glass would exhibit the desired stability and activity under in vivo conditions, electrochemical corrosion behaviour of HA-glass-titanium composites was estimated by anodic polarization measurement in a simulated body fluid, 0.001 N HCl solution, 0.1 M NaCl solution, 0.1% albumin solution, and 0.1% fibrinogen solution. Potentiostatic anodic polarization measurements were made from each rest potential to +2 V versus s.c.e. with an increasing rate of 1 mV/s. Anodic polarization curves for pure titanium provided typical passive corrosion behaviour in HCl solution. The breakdown potentials were +1.4 V in HCl solution and +1.2 V in other solutions. The glass-coated specimens showed extremely low current density, less than 0.001 microA/cm2, from rest potential to about +1.8 V, and showed a slight increase in current density over +1.8 V. The polarization curves for the HA-glass-Ti composites were quite different from those for Ti and the glass-coated specimens. The current density for 50-90% HA -glass-Ti composites increased drastically from less than 0.001 to 10 microA/cm2 around rest potential (about -0.5 V), and continued to rise slightly up to +2 V. Addition of protein in NaCl solution exhibited little effect on anodic polarization curves for Ti and HA-glass-Ti composites.

Biocompatible Materials↗
PubMed1991

Micro-observation and characterization of bonding between bone and HA-glass-titanium functionally gradient composite.

Bioactive composite implants consisting of hydroxyapatite (HA)-glass (G) ceramic layer and Ti-6AI-4V alloy, so-called HA-G-Ti functionally gradient implant, were provided for investigating the bonding behaviour of bone to the implant in vivo. The HA-G-Ti composites were implanted in femur and tibia of dog for various periods (1-12 month). Microstructural appearance of the interface between bone and the HA-G coating layer as well as the transverse sections of the HA-G coating layer and further apposition of bone to the implant have been studied in detail with SEM. The ingress of collagen fibres into the HA-G coating layer and the deposit of apatite on the collagen fibres and HA crystal grains being containing within the HA-G coating layer have been observed. Radiographical experiments indicate that the reparative process in the bone tissue surrounding the implants is markedly ahead even at one month after implantation. FT-IR measurement and X-ray diffraction were carried out for studying the characterization of the calcified bone matrix around the implants and the new bone proliferated along the HA-G-coated face (surface).

Animals↗
PubMed1991

Gamma-ray- and fission neutron-induced micronuclei in PHA stimulated and unstimulated human lymphocytes.

Two groups of normal human blood cells, one stimulated with phytohaemagglutinin (PHA) for 24 hr (G1-S phase of the cell cycle) and one unstimulated (G0 phase), were irradiated with 60Co gamma rays or 252Cf radiation. A comparison of radiation-induced micronucleus frequencies showed that the high-dose-rate gamma rays were more effective in inducing micronuclei than low-dose-rate gamma rays. In the cells exposed to low-dose-rate irradiation, there was little difference between the frequency of micronuclei in the G0 phase and the G1-S phase. However, cells in the G1-S phase were more sensitive than G0-phase cells to high-dose-rate gamma rays. The relative biological effectiveness of 252Cf neutron irradiation measured in micronucleus assays was consistent with the value obtained for the lethal effect of 252Cf on cultured cells.

Adult↗
PubMed1991

X-ray sensitivity of fibroblast cell strains derived from atomic bomb survivors with and without breast cancer.

Fibroblasts were established in vitro from skin biopsies obtained from 55 women and 1 man with or without breast cancer and with or without exposure to radiations from the atomic bomb (A-bomb) explosion in Hiroshima. The radiosensitivity of these cells was evaluated by clonogenic assays after exposure to X-rays. Dose-response curves were fitted to a multitarget model, S/S0 = A[1-(1-e-D/D0)N]. There was no difference in the means or variances of radiosensitivity between exposed and nonexposed groups, or between groups with and without breast cancer.

Breast Neoplasms↗
PubMed1990

Radiosensitivity of skin fibroblasts from atomic bomb survivors with and without breast cancer.

Fibroblasts were established in vitro from skin biopsies obtained from 55 women and 1 man with or without breast cancer and with or without exposure to radiation from the atomic bomb explosion in Hiroshima. The radiosensitivity of these cells was evaluated by clonogenic assays after exposure to X-rays or to fission neutrons from a 252Cf source. Data were fitted to a multitarget model, S/S0 = A [1 - (1 - ekD)N], for both X-ray and neutron dose-survival curves. A single hit model, S/S0 = AekD, fits the neutron dose-survival responses as well. There were no differences in the means or variances of radiosensitivity between exposed and nonexposed groups or between patients with or without breast cancer. Hence, although the sample is not large, it provides no support for the hypothesis that atomic bomb radiation preferentially induces breast cancer in women whose cells in vitro are sensitive to cell killing by radiation.

Adolescent↗
PubMed1990

Characteristics of the neutron field in the KEK counter hall.

We have measured the neutron leakage spectra outside the shielding in the KEK counter hall using a multisphere technique supplemented by the 12C(n, 2n)11C reaction in a carbon activation detector. The neutron spectra were derived from the measurements using the LOUHI78 unfolding code. The shape of these unfolded neutron spectra matched very closely that of spectra calculated by O'Brien and McLaughlin. A comparison of the dose equivalent as derived from the spectra with that measured by a neutron dose equivalent meter confirmed that the dose equivalent meter measurements usually underestimate the dose equivalent by at least 30%.

Methods↗
PubMed1990

Influence of test method on failure stress of brittle dental materials.

A bi-axial flexure test (piston-on-three-balls), a four-point flexure test, and a diametral tensile test were used to measure the failure stress of four brittle dental materials: zinc phosphate cement, body porcelain, opaque porcelain, and visible light-cured resin composite. Furthermore, the fracture probability of the bi-axial test specimens was predicted from the results of the four-point flexure test, with use of statistical fracture theory. Bi-axial failure stresses calculated from an equation developed by Marshall (1980) exhibited no significant difference for zinc phosphate cement as a function of piston size, specimen thickness, presence or absence of a stress-distributing film, and loading rate. The four-point flexure strength values of zinc phosphate cement and opaque procelain were significantly lower (p less than 0.05) than the corresponding mean bi-axial strength values, while the mean four-point flexure strength values of body porcelain and resin composite were not significantly lower (p greater than 0.05) than the corresponding mean bi-axial strength values. The diametral tensile strength of all materials was significantly lower than the bi-axial flexure strength. The mean bi-axial flexure strengths of zinc phosphate cement and opaque porcelain were much higher than the theoretical values predicted from surface flaw theory, while the strength values for body porcelain and resin composite were comparable with those determined from the four-point flexure test. These results demonstrate that the strength of zinc phosphate cement depends not only upon the geometric factors, but also upon sample preparation conditions.

Composite Resins↗
PubMed1990

Study on cases with posterior fossa epidural hematoma--clinical features and indications for operation.

In this retrospective study, 11 cases of posterior fossa epidural hematoma were analyzed in terms of clinical and radiological features, treatment, and outcome. Posterior fossa epidural hematomas accounted for 11.8% of all epidural hematomas encountered during the 7-year period studied. There were eight males and three females ranging in age from 2 to 53 years (mean, 20.7 years). Glasgow Coma Scale scores on admission were relatively good in many cases. Headache and/or vomiting were common symptoms on admission, whereas cerebellar signs were rare. As all 11 cases involved trauma, occipital fractures were present in eight (72.7%). Six patients underwent surgery. The indications for surgery, in terms of computed tomography findings, were: 1) the maximum thickness of the epidural hematoma was more than 15 mm; 2) the posterior fossa cisterns (e.g., the quadrigeminal and ambient cisterns) were poorly visualized; 3) there was marked deformity and/or displacement of the fourth ventricle; and 4) the hematoma extended to the supratentorial region and severely compressed the brain. At discharge, eight patients showed good recovery and one was moderately disabled. Two patients died. The prognosis for posterior fossa epidural hematoma appears relatively good, if it is not accompanied by severe primary brainstem injury and is diagnosed early, and appropriately and promptly treated.

Adolescent↗
PubMed1990

Heat curing behavior of light-cured composite resins investigated by dynamic differential scanning calorimetry.

The heat curing behavior of light-cured restorative composite resins, light-cured crown and bridge veneering resins, pure dimethacrylate monomers, Bis-GMA monomers containing various initiators, and monomer mixtures were investigated by slow heating at a constant rate with differential scanning calorimetry (DSC) without any light irradiation--the so-called dynamic DSC measurement. Some of the light-cured restorative composite resins and the light-cured crown and bridge veneering resins showed a sharp exothermic peak due to heat curing. Pure TEDMA also showed a sharp exothermic peak, whereas the Bis-GMA monomers containing catalysts for light curing showed no exothermic peak. It seems that heat curing behavior of light-cured composite resins depends not on the decomposition of camphorquinone, but on that of the monomer itself.

Acrylic Resins↗
PubMed1990

[Application of gypsum-bonded investment containing niobium carbide on casting of alloy for metal-ceramic restoration].

Experimental gypsum-bonded investments containing 0.5-5.0 wt% NbC were prepared by mechanical mixing of each powder. Setting and thermal expansion measurement, compressive strength and casting accuracy for Ni-Cr alloy for metal-ceramic restoration were investigated. Analysis of NbC during heating was carried out by X-ray diffraction, TG-DTA and SEM. NbC was oxidized to Nb2O5 with a volume change between 300-600 degrees C, as in the following equation: 2NbC + 4 1/2O2----Nb2O5 + 2CO2 The theoretical volume of 1/2Nb2O5 calculated from the lattice constants according to JCPDS file was approximately 4 times larger than that of NbC. The experimental investments of 70 wt% cristobalite and 30 wt% gypsum containing 2.0, 3.0 and 5.0 wt% NbC showed large thermal expansion of 7.0, 10.0 and 13.0% respectively. The investment containing 2.0 wt% NbC showed nearly the same casting accuracy for Ni-Cr alloys for metal-ceramic restoration as the commercial phosphate-bonded investment.

Calcium Sulfate↗
PubMed1990

[Three cases of carotid anterior cerebral anastomosis].

Three cases are presented with rare carotid-anterior cerebral anastomosis (anomalous ACA) originating from the internal carotid artery at the level of the origin of the ophthalmic artery, running first underneath and then between both optic nerves, and finally joining the anterior communicating artery. Case 1 (47 year-old woman) and case 2 (56 year-old man) were both admitted with subarachnoid hemorrhage from a ruptured aneurysm, which was located at the anomalous ACA (carotid-ACA anastomosis). Case (61 year-old man) was diagnosed as having left occipital intracerebral hematoma on CT, and bilateral anomalous ACA was found on angiograms. This anomalous ACA is very rare; only 21 cases have been reported in the literature. Several synonyms have been proposed as follows: 1) interoptic course of the anterior cerebral artery (ACA), 2) interoptic course of ACA, 3) an anomalous branch of the internal carotid artery (ICA) and 4) an anastomosis between the ICA and the ACA (carotid-ACA anastomosis). In cases with this carotid-ACA anastomosis, coexisting intracranial aneurysm has been reported. However, this is the first report of ruptured aneurysm located at the anomalous ACA itself. Case 1 and 2 were operated on through the ipsilateral pterional approach and the aneurysm was successfully clipped. Postoperative course was uneventful in each case. Case 3 was treated conservatively. From the angiographical and operative findings, we prefer to use "carotid-anterior cerebral artery anastomosis" as the medical terminology best suited to describe this condition.

Carotid Artery, Internal↗