Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 1,153 records · Page 64Linked to original sources

PubMed1989

[Basic studies on CaO-P2O5-MgO-SiO2-CaF system glass ceramics. 1. Morphology under the phase-contrast microscope and growth of cultured cells].

In order to determine the biocompatibility of glass ceramics which is one of the new biomaterials, in vitro studies were carried out by a cell culture method using four established cell lines. Materials used were glass ceramic disks with a diameter of 3 mm, and polystyrene coverslips of the same size as controls of the growth curve. Cells of each line were inoculated into 24-well multiplates at an appropriate density onto glass ceramic disks, and examined by phase contrast microscopy on the 1st, 3rd, 6th and 8th day. In addition, doubling time and saturation density were calculated from the growth curve. The results obtained were as follows. 1) Phase-contrast microscopy revealed that cells of each line attached to the disk within 24 hours and their numbers increased with time. After 8 days of cultivation, all of them reached confluence. 2) Contact with the glass ceramics did not cause cellular death or degeneration. Furthermore, the cultured cells showed the same morphological features as the control cells. 3) According to the growth curves, doubling time of all cells cultured with glass ceramics was shorter than that of the control cultures. On the other hand, saturation density was reduced to a minimum of 80% of the controls. These findings led to the conclusion that glass ceramic materials do not prevent the growth of cultured cells. According to the above results, glass ceramics possess the characteristics needed for bone grafts and implant materials.

Cell Line↗

PubMed1989

[Basic studies on CaO-P2O5-MgO-SiO2-CaF system glass ceramics. 2. Ultrastructural study on interface between culture cells and glass ceramics].

The aim of this study was to determine biocompatibility of glass ceramics and adhesion of cultured cells to glass ceramics. Four established cultured cell lines, human fibrosarcoma cells (HT-1080), human gingival carcinoma cells (Ca9-22), human osteosarcoma cells (NY) and mouse osteoblasts (MC3T3-E1), were used. For phase-contrast and electron microscopic observation they were cultured on substrates of glass ceramics or polystyrene coverslips as a control. The results obtained were as follows. Glass ceramics caused neither cellular degeneration nor death, as revealed by phase-contrast microscopy. By transmission electron microscopy an amorphous structure similar to the basal lamina was observed at the interface between the substrates and Ca9-22, and between glass ceramics and NY. A similar structure sometimes existed between the substrates and MC3T3-E1. On the other hand HT-1080 showed no such structure. The findings suggest that the biocompatibility of glass ceramics was satisfactory. Furthermore, from the clinical point of view it seems to be possible to close the material-tissue interface with epithelial, fibrocytic and osteocytic cells.

Animals↗

PubMed1989

Studies on the castability of Co-Cr alloy for cast plates. Part 1: The effects of sprue attachment direction to wax plates and the investment direction of refractory models.

Co-Cr alloy is used more frequently than Ni-Cr alloy as a non-precious alloy for cast plates in Japan. However, since the melting point of Co-Cr alloy is very high, about 1300 degrees C, and since it oxidizes easily, a vacuum-pressure casting machine capable of melting this alloy in a reduced atmosphere has recently been developed. Using this vacuum-pressure casting machine, the authors studied the effects on the Co-Cr alloy of the attachment direction of sprues and the investment direction of refractory models. The results clarified that in the vacuum-pressure casting method, sprue attachment direction and the investment direction of refractory models have a significant effect (p less than 0.01) on the castability of Co-Cr alloy.

Chromium Alloys↗

PubMed1989

Induction of membrane-associated interleukin 1 alpha (IL-1 alpha) by synergistic activation of human blood monocytes with interferon gamma and muramyl dipeptide analog.

Human blood monocytes isolated by centrifugal elutriation from healthy donors were tested for ability to produce membrane-associated IL-1 in response to activation stimuli such as various types of interferons (alpha, beta and gamma) and/or synthetic des-methyl muramyl dipeptide (norMDP). When monocytes were treated with norMDP or lipopolysaccharide (LPS) for 16 hr, they released IL-1 into their culture supernatant. When these activated monocytes were fixed with paraformaldehyde (PFA), they stimulated blastogenic responses of C3H/HeJ mouse thymocytes to PHA, suggesting that membrane-associated IL-1 could be induced by norMDP or LPS. Membrane-associated IL-1 was also found to be induced by the synergistic actions of suboptimal concentrations of rIFN-gamma and nor MDP, but not of rIFN-alpha A or rIFN-beta with norMDP. A specific anti-IL-1 alpha antiserum completely inhibited membrane-associated IL-1 activity, but did not affect the thymocyte-stimulating activity of fixed monocytes. IL-1 alpha was detected by fluorescence staining using the anti-IL-1 alpha antiserum on monocytes fixed after gamma IFN-gamma and norMDP. These results suggest that IFN-gamma may be important in expression of membrane-bound IL-1 alpha by the human blood monocytes responsible for regulation of immune responses in vivo.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1989

[Basic studies on the measurement of bone mineral content of mandible by quantitative computed tomography].

The basic studies were made in order to apply Quantitative Computed Tomography (QCT) to the measurement of mandibular bone mineral content. On the basis of the results, the bone mineral contents of the periapical region of the mandibular alveolar bone was measured in 10 normal subjects (5 male and 5 female: aged in their 20's). The obtained results were as follows. (1) The changes in CT numbers for 12 weeks under the same conditions of scanning were stable within the level of 1.0H.U. standard deviation. (2) The standard deviation of CT numbers obtained from the experiment with variable field sizes was under 14.5H.U.. The standard deviation of CT numbers obtained from experiments with subjects on various degrees of X-ray absorption was under 49.2H.U.. These results showed that CT numbers were considered to be unsatisfactory for use as a quantitative parameter. (3) The linearity of CT numbers and K2HPO4 liquid density was estimated by correlation coefficient. The linearity was proved to have a good correlation coefficient, above 0.999. And the correction made using a K2HPO4-QCT phantom considered to have a sufficient accuracy. (4) The accuracy of the measurement of the bone mineral density of the mandibular was estimated to be +/- 3.9mg/ml K2HPO4eq using a QCT phantom. (5) The bone mineral density of the total alveolar bone, the cortical and the spongy bone in the periapical region from premolar to molar was 503.5 +/- 55.7, 771.4 +/- 52.7 and 198.4 +/- 69.0mg/ml K2HPO4eq respectively. (6) No significant differences in bone mineral density depending on the location or sex were observed. (7) Significant differences in bone mineral surface density depending on the location were observed. The value was higher in molar than in premolar regions. But no significant difference between sexes was observed.

Adult↗

PubMed1989

[Anatomical studies on a supernumerary tooth considered to be a successional tooth of the lower first molar].

The purpose of this study is to investigate features of the successional tooth of the lower first molar. Materials investigated in this study deal with a supernumerary tooth formed at the distolingual deep part to the lower right first molar of a male patient aged twenty-four. It was observed with binocular microscopy and under X-ray. The occlusal surface of it was observed with scanning electron microscopy. Horizontal ground sections of it were prepared and observed with polarizing microscopy, fluorescent microscopy, and scanning electron microscopy. It is thought that this supernumerary tooth is a true successional tooth of the lower first molar because it was formed at the distolingual deep part to the lower first molar and the fissure of it is Y-shaped and it has five cusps. It is considered that two impressions at buccal and distal surfaces of it isn't original hereditary features but was accidentally formed by pressures of mesial and distal roots of the lower first molar. The rough form of it has most resemblance to the lower second premolar and distal and lingual parts of it are smaller than that of the lower first molar. But fundamental features of the lower first molar are preserved in it. It is thought that the center of the molarization field of human lower successional teeth lies at the successional tooth of the lower first molar because the form of the occlusal surface of it is more complex and functional than those of the lower first and second premolars.

Adult↗

PubMed1989

[Study on renal osteodystrophy using 2-compartment model analysis of bone scintigraphy. 1. Clinical significance of K Index].

The dynamic analyses of bone scintigraphy were performed in 30 cases of hemodialysed patients. The regression analyses between biochemical data or duration and K indexes obtained from the 2-compartment model analysis in the maxillofacial region were carried out. The obtained results were as follows. 1) The duration and K indexes were significantly correlated with 1 or 2% of significance level in the parietal bone and the zygomatic bone. 2) Serum Ca and K indexes were highly correlated in every settled ROI. The correlation coefficients were distributed from 0.58 to 0.79. In the cranial bone the correlation were more higher than in maxilla and mandibular bone. 3) Serum ALP and K indexes have more higher significant level of correlation than the results of Ca. The correlation coefficients were distributed from 0.48 to 0.83. The level of significance were changed by location. The highest correlation coefficient was 0.83 in the parietal bone. 4) Serum c-PTH and K indexes have significant correlation in every settled ROI with the correlation coefficient from 0.59 to 0.69. The significance level were nearly equal in every location. 5) In the case of subtotal parathyroidoectomy the K indexes which were abnormally high in preoperation showed the tendancy to decrease toward normal range in postoperation. These results indicated that K indexes reflected the bone change caused by renal osteodystrophy. And the K indexes considered to be usefull to estimate the bone improvement.

Bone and Bones↗

PubMed1989

[Histological study on the gingiva in PenCB poisoned beagle dogs].

We examined toxic effect of PenCB and therapeutic effect of squalane on the gingiva in PenCB poisoned beagle dogs. The results obtained were as follows. 1) PenCB exerted blood level-dependent changes of epithelial cells in which appearance of intracellular vacuoles and swollen mitochondria were observed. 2) Large vacuoles might be caused by degeneration of nerve ending were observed within the supra-basal layers. 3) We could not detect the definitive improvement in the gingiva of the PenCB poisoned beagle dogs followed administration of squalane.

Animals↗

PubMed1989

Myoinositol inhibits proliferation of cultured Schwann cells: evidence for neurotoxicity of myoinositol.

To determine whether so-called uraemic toxins exhibit direct toxic effects on Schwann cells, the latter were cultured in a monolayer with the addition of uraemic toxins. Proliferation of Schwann cells was estimated with [3H]-thymidine incorporation into DNA synthesis. Myoinositol, methylguanidine, guanidinosuccinic acid, parathyroid hormone, phenol, p-cresol, 4-hydroxyphenylacetic acid, 4-hydroxybenzoic acid, and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid were added at various concentrations to the culture medium. Addition of myoinositol at concentrations between 50 and 100 micrograms/ml, values analogous to those in in a dose-dependent way. Myoinositol also inhibited axolemma-stimulated proliferation of Schwann cells. The other compounds at concentrations occurring in uraemic serum did not show any toxic effect on Schwann cells. These results suggest that myoinositol has a neurotoxic effect on Schwann cells, and uraemic polyneuropathy seemed to be caused by a defect in maintaining normal myelin due to accumulation of myoinositol.

Animals↗

PubMed1989

Treatment of pathologic emotionality with thyrotropin-releasing hormone.

Thyrotropin-releasing hormone (TRH) has been reported to be effective in some neuropsychiatric diseases. We examined the effect of TRH on the syndrome of pathologic laughing or crying in four patients with multiple cerebral infarction and one with olivo-ponto-cerebellar atrophy (OPCA). We found a marked therapeutic effect of the peptide on pathologic laughing with a slight improvement in ataxia in a patient with OPCA. A marked diminution in frequency of their pathologic crying with TRH was achieved in two patients with multiple cerebral infarction. The two other patients did not respond to TRH. Levodopa was administered to these patients to compare with TRH in therapeutic efficacy on the symptom and was effective in only one of four patients. The concentration of homovanillic acid in cerebrospinal fluid had diminished in two of the four patients. The results suggest that the tripeptide is effective in the control of this syndrome. We discuss the underlying mechanism(s) of the syndrome and the mode(s) of action of TRH.

Affective Symptoms↗

PubMed1989

[A case of complete rupture of the righ TMJ disc].

A case of complete rupture of the right TMJ disc was described. A 43 year old woman visited our hospital with the chief complaint of a mild pain in the right TMJ. Initially, a conservative treatment using the occlusal splint (condylar repositioning appliance) was carried out. This was because she had reciprocal clicking of the right TMJ which had occurred not long before and it seemed that the symptoms were due to the trouble with the disc. In spite of this treatment, for 6 months no improvement was obtained and the reciprocal clicking changed into crepitation. Moreover the double contrast arthrotomographic image indicated a perforation or a wide rupture of the disc, and deformities of the articular bone. Then a right TMJ osteoarthrosis with wide (complete) disc rupture was diagnosed, and a discectomy was performed. The symptoms were greatly reduced by this treatment. It was conceivable that the steroid which she had used for a long time to treat bronchial asthma caused a remarkable inhibition of the tissue repairing, and an internal derangement of the TMJ rapidly progressed to osteoarthrosis.

Adrenal Cortex Hormones↗

PubMed1989

[Automatic control of total artificial heart to simulate the hemodynamics under natural heart circulation].

We developed control system of total artificial heart (TAH) during exercise simulating the circulatory response of natural heart. The following procedures were taken to develop this system. 1) Measurement of hemodynamics and physical activity rate (PAR) of natural heart goats during treadmill exercise. 2) Estimation of cardiac output from PAR using a non-linear model. 3) Development of a pneumatic artificial heart (AH) driver with high speed controllability and a control unit to deliver CO calculated from PAR beat by beat. 4) Evaluation of the physiological condition of the TAH goat during exercise controlled by this system. Using this control method, CO of TAH goats was similar to that of natural heart goats during treadmill exercise. Hypertension was observed during exercise. This hypertension was considered to be derived from two causes. One was high inflow and outflow resistance of cannulae between AH pump and living body. The other was the disorder of peripheral circulatory control mechanism in TAH animal. Such as increased sympathetic activity, insufficient secretion of atrial natriuretic polypeptide (ANP) and decreased sensitivity of peripheral circulatory system with ANP.

Animals↗

PubMed1989

Increment of Tal positive cells in peripheral blood from patients with rheumatoid arthritis.

Recently it was demonstrated that the Tal antigen is a marker for activated T cells and the population of Tal+ cells includes memory T cells. Our study was undertaken to analyze Tal+ cells in peripheral blood from patients with rheumatoid arthritis (RA) and examine the correlation between the proportion of Tal+ cells and disease activity. Using a dual immunofluorescent method, T cell subsets were analyzed in peripheral blood from 46 patients with RA, 10 patients with osteoarthritis (OA) and 10 healthy subjects. Patients with RA had a significantly higher percentage of T cells bearing the Tal antigen than patients with OA and healthy subjects. Furthermore, the percentage of CD3+Tal+ cells in peripheral blood from patients with RA was significantly correlated with disease activity including erythrocyte sedimentation rate, morning stiffness and the Lansbury index, whereas CD3+ HLA-DR+ cells did not correlate. In serial observations in patients with RA, the percentage of CD3+ Tal+ cells decreased in accordance with the improvement of disease activity. Thus, we suggest that the percentage of Tal+ cells may be a marker of the disease activity in patients with RA.

Aged↗

PubMed1989

[Spinal subdural empyema diagnosed by MRI and recovered by conservative treatment].

Localized suppuration involving the spinal cord is uncommon. A case of spinal subdural empyema is reported. The patient is 54-year-old male who had been suffering a diabetes mellitus but did not receive any treatment. His initial symptom was lumbago. Then he noticed a palpitation and general malaise which made him visit a hospital. Because he did not show any improvement by a fluid therapy, he was transferred to our institute for the further evaluation. On admission, physical examination showed no abnormality. Blood pressure was 170/90 mmHg, heart rate 128/min. and body temperature 37.1 degrees C suggesting a septic shock state. Neurological examination revealed slight consciousness disturbance, mild tetraparesis and bilateral hypesthesia lower than the level of L3. Laboratory examination showed the elevated leukocyte count and fasting blood sugar and urine ketone body levels of 20,500/mm3, 257 mg/dl and 226 mg/dl respectively. Blood culture proved a septicemia of Streptococcus agalactiae afterwards. On the second day of admission, lumbar puncture revealed a purulent cerebrospinal fluid, though X-ray CT of lumbar spine did not confirm a diagnosis. Spinal magnetic resonance imaging (MRI) revealed a widespread abnormal intensity of the spinal canal from the level of Th11 to L4. On the T1-weighted image (TR 300 msec., TE 40 msec.), cerebrospinal fluid space was abnormally isointense. On the T2-weighted image (TR 2,000 msec., TE 80 msec.), subdural and cerebrospinal space was filled with an abnormal high-intense lesion especially on the ventral side. He developed semicoma due to hydrocephalus following a intraventricular empyema. He was also complicated disseminated intravascular coagulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1989

[Clinical application of subrenal capsule assay in ovarian cancer].

The 6-day subrenal capsule assay (SRC) in normal immuno-competent mice was used to test the responsiveness of ovarian cancer to combination chemotherapy and assess the usefulness of SRC in clinical application. A total of 18 different patients in 22 different assays were studied. Twenty-one assays (95%) were evaluable. The predictive sensitivity was 50%, the predictive resistance 75% and the predictive total accuracy 55% respectively. Sensitive drugs in repeated assays in four patients were not changed. Etoposide, cyclophosphamide, cis-platin and adriamycin were sensitive. Etoposide was the most sensitive of four drugs. The response rate was 50% in the patients treated with etoposide as the first line chemotherapy and the second line chemotherapy, respectively. Patients who were treated with sensitive drugs in SRC survived longer than the patients treated with cis-platin combined chemotherapy without etoposide. The median survival time was 19 months and the mean progression free interval was 15 months. In the results of this study, the value of SRC was supported by the results of chemosensitivity tests and etoposide seems useful in chemotherapy in ovarian cancer.

Adult↗

PubMed1989

[Clinical study of taste abnormalities in advanced lung cancer cases].

Taste recognition thresholds for four basic tastes, sweet, salty, and bitter, have been examined in 36 advanced lung cancer patients to identify the presence or absence of taste abnormalities in such patients. Twenty-six untreated lung cancer patients, or 65.3%, demonstrated an abnormal taste threshold for at least one of the 4 taste, a result varying significantly from suitable controls (p less than 0.05). Among the total 36 lung cancer patients, the number of those showing a threshold abnormality was no different between the smoker and non-smoker groups, though abnormalities were higher in the low serum zinc level group than in the normal serum zinc level group (p less than 0.05). We also observed transient threshold elevations after chemotherapy including Cisplatin. Thus, it is thought that taste abnormalities are more prevalent in advanced lung cancer patients.

Adult↗

PubMed1989

[Three patients with hypopituitarism accompanied by primary empty sella presenting mental symptoms].

We report here three patients with hypopituitarism accompanied by primary empty sella, whose first manifestations were various mental symptoms. Endocrine studies revealed that two patients showed panhypopituitarism and the other had isolated adrenocorticotropin (ACTH) deficiency. Although several different types of pituitary dysfunctions have been described in a mild form, empty sella is usually asymptomatic. Their first manifestations were mental symptoms; consciousness disturbance, psychomotor agitation, visual hallucination and delusion. Isolated ACTH deficiency is an uncommon disease which etiology is still undetermined. A case with isolated ACTH deficiency associated with an empty sella has been reported before. It is suggested that empty sella might have a role in pathogenesis of isolated ACTH deficiency. The empty sella was confirmed by metrizamide cisternography and magnetic resonance imaging (MRI). These imaging studies are good tools to disclose empty sella. Replacement with cortisone and levothyroxine resulted in an improvement in the mental symptoms in two patients with panhypopituitarism. No alteration was observed following cortisone administration in the patient with isolated ACTH deficiency. Delusion and visual hallucination in this patient poorly responded to treatment with neuroleptics.

Empty Sella Syndrome↗

PubMed1989

[Assay of erythropoietin in plasma by enzyme-linked immunosorbent assay].

Using an enzyme linked immunosolvent assay kit supplied by Toyobo Co., erythropoietin (EPO) concentration in plasma was measured. Normal 100 samples showed a logarithmic distribution in EPO concentrations and normal range was between 5.4-32.5 mU/ml (mean +/- 2 SD). Coefficient variations (C.V.) of 3 samples continuously assayed were 3.8%, 6.5%, and 9.1% and C.V. of 3 samples assayed day by day were 3.6%, 7.2%, and 11.5%. Dilution test revealed that 3 samples diluted to 75%, 50%, and 25% were on each line which go through zero point. After the addition of 5.0, 15.0, and 35.0 mU/ml of EPO to the 3 samples, assay of EPO revealed 95.5 +/- 6.3% (mean +/- SD) of recovery. Assay of EPO in plasma from 19 patients with aplastic anemia revealed that all samples were higher than normal range and that 4 samples from the patients with severe aplastic anemia (less than 8.0 g/dl of hemoglobin) showed higher than 3,000 mU/ml. Furthermore, 67% (14/21) of samples from patients with leukemia showed higher than normal range in EPO concentration. EPO concentration in plasma from 17 patients with chronic renal failure were within normal range although the patients showed anemia.

Adult↗