Biomedical subjects

S Ban

Publications and source records attributed to S Ban.

At least 91 records · Page 5Linked to original sources

PubMed1994

Calcium phosphate precipitation on the surface of HA-G-Ti composite under physiologic conditions.

Hydroxyapatite-glass-titanium (HA-G-Ti) functionally gradient composite plates bound face-to-face by nylon wire were soaked in a simulated body fluid. The gap between the plates was filled with the precipitates after soaking for 6 months, and a tight chemical bond was formed between them. Field emission-type (FE) scanning electron microscopy (SEM) and transmission electron microscopy observations revealed that the growth rate and morphology of the precipitates differed widely from the outside portion to the inside one on the surface region of the composite plates. In the portion relatively near the outside, the mutually bonded portion, needle-like precipitates with preferred orientation to the c-axis were markedly observed. From the results of Fourier transform infrared spectroscopy and energy dispersive x-ray microanalysis, it was found that the precipitates were Ca-deficient carbonate apatite with low crystallinity. On the other hand, HA-G-Ti composite rods were implanted in the femur of beagle dogs for 3 months. FE-SEM observations demonstrated that needle-like precipitates were deposited on both the surfaces of the composite and bone at the portion having a narrow gap, about 0.1-0.2 mm between them prepared deliberately before implantation. It was found that both the morphologies and the composition of the precipitates in vivo were similar to those in vitro. It is concluded that the HA particles on the surface of the composite act as nucleation sites for precipitation in physiologic environments, whereas the glass matrix is independent to it.

Animals↗

PubMed1994

Radiographic patterns of osteomyelitis in the mandible. Plain film/CT correlation.

Mandibular osteomyelitis often is associated with involvement of the masticator space. Assessment of mandibular osteomyelitis should therefore involve assessment of soft tissue involvement of the lesion. The purpose of this study was to clarify the relationship between computed tomography patterns and the presence of inflammation in soft tissues. Thirty-three cases diagnosed with osteomyelitis of the mandible were analyzed radiologically with conventional radiographs and with computed tomography scans. Computed tomography patterns of osteomyelitis were classified into four types, lytic, mixed, sclerotic, and sequestrum patterns. Location, extent of the lesion, and change of the cortical plate were evaluated and compared with conventional radiographic findings. Mixed pattern cases displayed diffuse bone abnormalities, which sometimes were accompanied by cortical plate disruption and periosteal reaction. In addition, most mixed pattern cases showed soft tissue involvement, especially of the masseter muscle. Inflammation of the masseter muscle was found to be related to periosteal reaction and disruption of the buccal cortical plate. The data demonstrate a close interaction between cortical plate disruption and muscle inflammation. The extent of inflammation including soft tissue involvement was better appreciated with computed tomography in osteomyelitis, especially in mixed pattern cases.

Adolescent↗

PubMed1994

An unusual type of Hangman's fracture with cord compression: a case report.

An unusual case of hangman's fracture with neurologic sequelae is described in a 43-year-old woman. The fracture involved the body of C-2 with gross dislocation of the anterior part of C-2 and C-1 forward on C-3, associated with severe cord compression. The patient was successfully treated with a decompression of the foramen magnum and C-1 laminectomy, accompanying in situ fusion. The images obtained by computed tomography and magnetic resonance imaging were useful in understanding the true nature of the injury and planning the appropriate surgical treatment.

Adult↗

PubMed1994

Increased attenuation in odontogenic keratocysts with computed tomography: a new finding.

An increased attenuation area (IAA) is sometimes seen in the cystic cavity of odontogenic keratocysts (OKCs) on CT scans. The significance of IAA was compared radiologically and histologically in 26 cysts in which a provisional diagnosis of OKC had been made. First, the presence of IAA in the cystic cavity was assessed. Then, relationship between the presence of IAA and data obtained from the cysts, including the CT and histological findings and the visual appearance of the cyst contents, was evaluated. An IAA was frequently seen in large multilocular cysts. There was no relationship between the presence of IAA and aggressive features of the cyst on CT or the cyst contents. Histologically, subepithelial inflammation was often observed in the cysts with IAA. In order to ascertain whether the IAA was due to the keratin mass, a CT scan of a bundle of hair in a water bath was performed and shown to have a similar density. Our study demonstrated that IAA in cystic cavities results from desquamated keratin. Since this seems to occur in long-standing or inflamed multilocular OKCs, it could be used as a significant finding in the diagnosis of OKC.

Adolescent↗

PubMed1994

Spontaneous subperiosteal hematoma of the orbit--case report.

A 62-year-old female was admitted with complaints of sudden proptosis of the left eye and severe left orbital pain without history of trauma or previous illness. Computed tomography and magnetic resonance imaging demonstrated a biconvex extraconal hematoma in the upper part of the left orbit. Surgical exploration of the orbit revealed the presence of a subperiosteal hematoma without a causative lesion. Such spontaneous subperiosteal hematoma of the orbit is extremely rare, but may result from an occult vascular disorder.

Craniotomy↗

PubMed1994

[Traumatic anterior cerebral artery aneurysm difficult to distinguish from congenital cerebral aneurysm: case report].

We report the case of a 29-year-old woman in whom a saccular aneurysm of the distal anterior cerebral artery developed following head trauma due to a car accident. She was semicomatose on admission but had no lateralizing motor signs. Reflexes were symmetrical, with bilateral extensor toe sign. X-ray of the skull showed no fracture but CT scans demonstrated a large frontal hematoma and interhemispheric bleeding. Initial cerebral angiography performed within 12 hours of trauma showed a small protrusion on the pericallosal portion of the left pericallosal artery with no branching point nearby. Angiography was repeated on the 9th day after admission and confirmed the presence of a saccular aneurysm of the pericallosal artery, which had been visible as a small protrusion on the initial angiogram. Traumatic aneurysm was suspected and successful neck clipping of the aneurysm was performed on the 14th day. Preoperative CT and angiographic findings could not rule out a congenital aneurysm but the histological study of the specimen confirmed that it was a traumatic false aneurysm. We discussed the diagnosis and the etiology of posttraumatic aneurysm.

Adult↗

PubMed1994

[Peritumoral hemorrhage after radiosurgery for metastatic brain tumor: a case report].

An unusual case of peritumoral hemorrhage after radiosurgery for the treatment of metastatic brain tumor is reported. This 64-year-old woman had a history of breast cancer and underwent right mastectomy in 1989. She remained well until January 1993, when she started to have headache, nausea and speech disturbance, and was hospitalized on February 25, 1993. Neurological examination disclosed right hemiparesis and bilateral papilledema. CT scan and MR imaging showed a solitary round mass lesion in the left basal ganglia region. It was a well-demarcated, highly enhanced mass, 37mm in diameter. Cerebral angiography confirmed a highly vascular mass lesion in the same location. She was treated with radiosurgery on March 8 (maximum dose was 20Gy in the center and 10Gy in the peripheral part of the tumor). After radiosurgery, she had an uneventful course and clinical and radiosurgical improvement could be detected. Her neurological symptoms and signs gradually improved and reduction of the tumor size and perifocal edema could be seen one month after radiosurgery. However, 6 weeks after radiosurgery, she suddenly developed semicoma and right hemiplegia. CT scan disclosed a massive peritumoral hemorrhage. Then, emergency craniotomy, evacuation of the hematoma and total removal of the tumor were performed on April 24. Histopathological diagnosis was adenocarcinoma. It was the same finding as that of the previous breast cancer. Histopathological examination revealed necrosis without tumor cells in the center and residual tumor cells in the peripheral part of the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMed1994

[Dilated pericerebellar fluid space in patients with chronic subdural hematoma].

It is not uncommon to observe the dilation of the pericerebellar fluid space (PCFS) on CT in patients with chronic subdural hematoma (CSDH). CT scans of 92 patients with CSDH proven by surgery were reviewed with respect to the dilatation of PCFS and we evaluated the incidence of dilated PCFS and the relationship between PCFS and other factors. There were 68 males and 24 females. Patients ranged in age from 20 to 90 years (mean 65.2 years). Another 50 patients without CSDH were also reviewed as a control group. A new PCFS grading based on the CT findings was proposed, divided into 3 grades as follows. In grade 0, no PCFS could be seen on CT scans. In grade 1, PCFS could be detected along the posterior aspect of the petrous pyramid, and in grade 2, PCFS could be seen not only along the posterior aspect of the petrous pyramid but also under the tentorium cerebelli. The dilation of PCFS was seen in 78 patients (84.8%) out of the 92 cases. In 50 patients without CSDH (control group), the dilatation of PCFS was noted only in 6 (12%). The dilatation of PCFS was almost always seen on the same side as the CSDH. Among many factors, the significant factor was the degree of the midline shift, the bigger the midline shift caused by CSDH, the larger was the dilated PCFS. Although the mechanism of the dilated PCFS in patients with CSDH is not clear, it is postulated that the mechanism is caused by CSF flow disturbance, compression or adhesion of the subarachnoid space due to CSDH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Analysis of maxillary sinusitis using computed tomography.

Odontogenic maxillary sinusitis can be defined as sinusitis induced by a dental lesion. We examined the CT findings of 68 patients with maxillary sinusitis in order to differentiate between inflammation of sinus origin and inflammation of dental origin. Maxillary sinusitis was classified into four types according to clinical symptoms, history and conventional radiographic findings: type 1, simple sinusitis; type 2, odontogenic sinusitis; type 3, mixed sinusitis; type 4, slight sinus abnormality with a dental lesion. The relationship between the type of maxillary sinusitis and CT findings was analysed. Type 1 sinusitis exhibited severe pathological changes in both mucosa and bone which often extended into the nasal cavity and other paranasal sinuses. Type 2 sinusitis exhibited localized pathology on the unilateral antral floor. Type 3 sinusitis exhibited severe pathology characteristic of type 1 combined with type 2 sinusitis. Type 4 sinusitis could be differentiated by the CT findings into type 1 or type 2 sinusitis. The classification of sinusitis in this manner has implications for treatment planning, and CT should therefore be performed when conventional radiography does not provide sufficient information.

Female↗

PubMed1993

Factors affecting the transformation of octacalcium phosphate to apatite in vitro.

A fresh octacalcium phosphate (OCP) precipitate without drying and three kinds of dried OCP powders were soaked for 3 weeks in 11 kinds of physiological solutions consisting of different combinations of Ca2+, Mg2+, K+, Na+, HCO3-, HPO4(2-), F-, albumin, collagen and alkaline phosphatase, in three different pH values and at three different temperatures. X-ray diffraction study showed that most of the OCP had been transformed to apatite with low crystallinity after soaking in the solutions without Mg2+. The IR absorption spectra revealed that CO3 was incorporated in the apatite formed from OCP in the solution without Mg2+, whereas OCP changed little after soaking in the solution containing Mg2+. These results suggest that the presence of Mg2+ in the solution is one of the most effective means of inhibiting the transformation of OCP to apatite by interrupting the precipitation process of apatite.

Analysis of Variance↗

PubMed1993

Application of generalized estimating equations to a study of in vitro radiation sensitivity.

We describe an application of the generalized estimating equation (GEE) method (Liang and Zeger, 1986, Biometrika 73, 13-22) for regression analysis of correlated Poisson data from a split-plot design with a small number of experimental units. As an alternative to the use of an arbitrarily chosen working correlation matrix, we demonstrate the use of GEE with a reasonable model for the true covariance structure among repeated observations within individuals. We show that, under such a split-plot design with large clusters, the asymptotic relative efficiency of GEE with simple (independence or exchangeable) working correlation matrices is rather low. We conclude by summarizing issues and needs for further work concerning efficiency of the GEE parameter estimates in practice.

Biometry↗

PubMed1993

[Complication of gastro-duodenum with intra-hepatic arterial infusion chemotherapy using implantable reservoir system for hepatic tumors].

The subjects were 20 cases with implantable reservoir systems for unresectable hepatic tumors. We evaluated the correlation between a complication of the gastro-duodenum after intra-hepatic arterial chemotherapy and a gastro-duodenal distribution of anti-cancer drugs using the hepatic perfusion scintigram by 99mTc-macroaggregated albumin via reservoirs. The 20 cases were divided into 3 groups (A, B, C) according to the level of gastro-duodenal accumulation of 99mTc-MAA. In group A with the strongest accumulation in the gastro-duodenum, we frequently found a gastro-duodenal ulcer after intra-hepatic arterial chemotherapy. There was a significant difference between group A and group C, the latter without a gastro-duodenal accumulation. These results suggested that the hepatic perfusion scintigram via reservoir was a useful examination to expect and prevent the complication of gastro-duodenum on intra-hepatic arterial infusion (especially continuous infusion) chemotherapy.

Carcinoma, Hepatocellular↗

PubMed1993

Radiosensitivity of atomic bomb survivors as determined with a micronucleus assay.

If A-bomb survivors include a disproportionately large number of either radioresistant or radiosensitive persons, the surviving population would provide a biased estimate of the true risk of radiogenic cancer. To test this hypothesis, the in vitro X-ray sensitivities of peripheral blood lymphocytes obtained from 937 A-bomb survivors were measured with a cytokinesis-blocking micronucleus assay. Background frequencies (no irradiation in vitro) of micronuclei show a wide distribution. Frequencies in both males and females tend to increase with increasing donor age. Frequencies in females are significantly higher than those in males. Donor age decreases the sensitivity of lymphocytes to in vitro X-ray exposure at a rate of about 0.001 micronuclei per cell per year per gray. There is no effect of donors' sex on in vitro radiation sensitivity. Atomic bomb radiation and cigarette smoking had no significant effect on background and X-ray-induced micronuclei frequencies. Thus there is no difference in radiosensitivity of peripheral blood lymphocytes between proximally and distally exposed survivors.

Age Factors↗

PubMed1992

[Experimental model of liver metastases of the mouse].

3 syngeneic tumor-mouse systems were used to establish experimental model of liver metastasis. Only one system, SC42-DS, was suitable for the purpose. When 2 x 10(5) SC42 tumor cells was injected into the spleen of DS mouse and splenectomy was done after 24 hours preventing of spleen tumor due to implantation, multiple nodular liver metastasis were observed in all mice after 14 days. The numbers of nodulus were well correlated with the liver weight.

Animals↗

PubMed1992

[Prevention of mouse liver metastases by perioperative immunostimulation using OK-432].

Two surgical procedures were required to make experimental model of liver metastasis (SC42-DS). In this paper, the protective effects of OK432 against liver metastasis were examined experimentally, as a immunotherapeutic agent under perioperative condition. In 5 combinations of administration, OK432 showed some different effects on liver metastasis, however, in general, simultaneous intrasplenic injection of OK432 reduced liver metastasis. From this result, the efficacy of intraoperative OK432 via portal vein was speculated.

Animals↗

PubMed1992

Central nervous system changes in mitochondrial encephalomyopathy: light and electron microscopic study.

An autopsy case of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is reported. It presented with generalized muscle atrophy, stroke-like episodes, schizophrenia-like mental disorder and progressive dementia. Serum lactate and pyruvate levels were high. In the biopsied muscles, ragged-red fibers were observed by light microscopy and aggregation of abnormal mitochondria with paracrystaline formation by electron microscopy. The most characteristic neuropathological findings were infarct-like lesions widespread in the cerebral cortex. In addition, this case showed some unusual pathological features: (1) diffuse moderate fibrillary gliosis in the whole cerebral and cerebellar white matter, which might have been due to metabolic disturbances; (2) several focal lesions with demyelination and numerous spheroids in the pontocerebellar fibers; and (3) marked degeneration of the posterior columns and spinocerebellar tracts. Electron microscopic examination revealed that abnormal mitochondria were markedly aggregated in smooth muscle cells and endothelium of the cerebral and cerebellar blood vessels. These fine structural findings suggest a "mitochondrial angiopathy".

Acidosis, Lactic↗

PubMed1992

Effect of loading conditions on bi-axial flexure strength of dental cements.

A ball-on-three-ball bi-axial flexure test was used to evaluate the flexure strengths of five kinds of dental cements (zinc phosphate, polycarboxylate, glass ionomer, silicate, and zinc oxide-eugenol cements). The bi-axial flexure strengths of zinc phosphate cement discs of variable dimensions were also measured to determine the size effects of test specimens. Finite element stress analyses were performed on disc specimens which were subjected to both a concentrated load and a uniformly distributed load. The observed values were compared with the theoretical value calculated by the finite element method. A ball-on-three-ball bi-axial flexure test could not be used for thicker specimens, since the fracture origin of these specimens is more likely to occur on the loaded side.

Dental Cements↗

PubMed1992

An autopsy case of mitochondrial encephalomyopathy (MELAS) with special reference to extra-neuromuscular abnormalities.

An autopsy case of a 37-year-old man with mitochondrial encephalomyopathy is reported. Ragged-red fibers and crystalline inclusions in mitochondria were revealed by biopsy of the striated muscle of the patient. Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) was diagnosed clinically. In addition to severe atrophy and degeneration of the generalized striated muscles and many foci of laminar necrosis of the cerebral cortex, the following abnormalities were observed: 1) hypertrophy of the myocardium, 2) fatty change of the liver, 3) focal sclerosis of the glomeruli and dilatation of the tubules of the kidneys, 4) hyalinous degeneration of the Langerhans' islands of the pancreas and 5) wavy change of the smooth muscle fibers of the muscularis propria of the gastrointestinal tract. We suggest that mitochondrial encephalomyopathy affects various organs and tissues, among which susceptibility of the muscular tissues--skeletal muscle, myocardium and smooth muscle--is high.

Adult↗