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Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 289 records · Page 16Linked to original sources
PubMed2000

Relationship between gingival health and dental caries in children aged 7-12 years.

The purpose of this study was to investigate the relationship between gingival health and dental caries in elementary school children in Japan. The subjects were 474 children aged 7 to 12 years who attended dental check-ups at an elementary school. The Oral Rating Index for Children, which consists of five categories (+2, +1, 0, -1, -2), was used to rate the findings of the gingival health examination. The dental examination was performed using the WHO caries diagnostic criteria for DMFT. Children were divided into three groups: a healthier group (H-group) made up of those scoring +2 (excellent) or +1 (good), an equivocal group (E-group) made up of those scoring 0, and a gingival less-healthy group (L-group) made up of those scoring -2 (very poor) or -1 (poor). Overall percentages for the H-group, E-group and L-group were 48.3%, 21.5% and 30.2%, respectively. The number in the L-group increased with increasing age. The mean scores of the DT and DMFT in the H-group were significantly lower than those in the L-group (p < 0.01 and p < 0.05, respectively). The results suggest that oral hygiene instruction should be given to children in order to motivate self-care, not only to avoid dental caries but also to prevent gingivitis.

Age Factors↗
PubMed2000

Magnetometric evaluation for the effects of silicon carbide whiskers on alveolar macrophages.

Alveolar macrophages are thought to play an important role in fibrogenesis in the lungs caused by various types of exposure to dust. In this experiment, we evaluated the effect of silicon carbide whiskers (SiC) on alveolar macrophages mainly by unique magnetometry and also by established methods such as lactate dehydrogenase (LDH) activity, apoptosis measurement and morphological observations. Alveolar macrophages obtained from Syrian golden hamsters by bronchoalveolar lavages were exposed in vitro to Fe3O4 for 18 hours as an indicator for magnetometry and SiC for experiments. A rapid decrease of the remanent magnetic field, so called "relaxation", was observed after cessation of an external magnetic field in macrophages phagocytizing Fe3O4 alone, while relaxation was delayed in those concurrently exposed to SiC. Release of LDH from SiC-exposed macrophages into the medium was not significantly higher than the controls, but it increased dose-dependently. Apoptosis was recognized in macrophages exposed to 60 micrograms/ml of SiC by the DNA ladder detection method and morphological observations. Electron microscopic examination revealed irregular forms of nuclei and organellas in macrophages exposed to SiC. Magnetometry, LDH release and electron microscopic observation indicated mild cytotoxicity of SiC to alveolar macrophages.

Animals↗
PubMed2000

Use of spiral computerized tomography angiography in patients with subarachnoid hemorrhage in whom subtraction angiography did not reveal cerebral aneurysms.

OBJECT: Patients with subarachnoid hemorrhage (SAH) in whom angiography does not demonstrate diagnostic findings sometimes suffer recurrent disease and actually harbor undetected cerebral aneurysms. The management strategy for such cases remains controversial, but technological advances in spiral computerized tomography (CT) angiography are changing the picture. The purpose of this prospective study was to examine how spiral CT angiography can contribute to the detection of cerebral aneurysms that cannot be visualized on angiography. METHODS: In 134 consecutive patients with SAH, a prospective search for the source of bleeding was performed using digital subtraction (DS) and spiral CT angiography. In 21 patients in whom initial DS angiography yielded no diagnostic findings, spiral CT angiography was performed within 3 days. Patients in whom CT angiography provided no diagnostic results underwent second and third DS angiography sessions after approximately 2 weeks and 6 months, respectively. Six patients with perimesencephalic SAH were included in the 21 cases. Six of the other 15 patients had small cerebral aneurysms detectable by spiral CT angiography, five involving the anterior communicating artery and one the middle cerebral artery. Two patients in whom initial angiograms did not demonstrate diagnostic findings proved to have a ruptured dissecting aneurysm of the vertebral artery; in one case this was revealed at autopsy and in the other during the second DS angiography session. A third DS angiography session revealed no diagnostic results in 13 patients. CONCLUSIONS: Spiral CT angiography was useful in the detection of cerebral aneurysms in patients with SAH in whom angiography revealed no diagnostic findings. Anterior communicating artery aneurysms are generally well hidden in these types of SAH cases. A repeated angiography session was warranted in patients with nonperimesencephalic SAH and in whom initial angiography revealed no diagnostic findings, although a third session was thought to be superfluous.

Adult↗
PubMed2000

Effect of a radical scavenger "water soluble protein" from broad beans (Vicia faba) on antioxidative enzyme activity in cellular aging.

We isolated a free-radical scavenger "water soluble protein (WSP)" from broad beans. Hydrocortisone (HC) is known to inhibit superoxide generation and was used as the reference scavenger. WSP was examined for its effect on antioxidation in young (PDL 20, 25% of the maximum life span) and old (PDL 50, 62.5% of the maximum life span) human fibroblasts (TIG-1). Cells were treated with WSP or HC for 4 and 6 wk in young cells, and for 3 and 6 wk in old cells. The cytosolic superoxide dismutase activity in the cells treated with WSP or HC tended to decrease as compared with that in the non-treated cells (control) with the exception of WSP-treated young cells 4 wk after culturing. Young cells were equal in glutathione peroxidase activity to the control, but the activity level in WSP- or HC-treated young cells 6 wk after culturing was 10-50% lower than that in the control. Young and old cells treated with WSP or HC were superior to the control in catalase activity with the exception of HC-treated old cells. WSP- or HC-treated cells were higher in glutathione (GSH) concentration than the control with the exception of WSP-treated young cells 4 wk after culturing and HC-treated old cells 6 wk after culturing. Such increases in catalase activity and GSH concentration by WSP treatment may be related to the delay of cellular aging-dependent degeneration.

Antioxidants↗
PubMed2000

HPLC analysis and optimization of enzymatic synthesis of 4'-O-(beta-D-glucopyranosyl)-D-pantothenic acid.

We analyzed beta-glucosidase-catalyzed transglucosylation to D-pantothenic acid using a reversed-phase HPLC system in order to obtain 4'-O-(beta-D-glucopyranosyl)-D-pantothenic acid (PaG) at a higher yield. The HPLC system was simpler and more straight-forward for the PaG analysis than the previously employed bioassay method and could also be adopted for efficient isolation of PaG. Penicillium decumbens naringinase showed the highest glucosyl transfer activity to D-pantothenic acid, and the reaction using smaller amounts of naringinase for prolonged periods of reaction time (70 h<) was important to attain higher yields of glucosyl transfer. Maximum overall yields of PaG of 10 and 4% (mol/mol, based on D-pantothenic acid) were obtained using beta, beta'-trehalose and cellobiose, respectively, as glucosyl donors. The value was 3.6- and 1.4-times higher, respectively, than that obtained by previous synthesis and isolation procedures.

Animals↗
PubMed2000

[Technical evaluation of video-assisted lung resection for lung cancer].

There are two major problems including indications and techniques in video-assisted lung resection for lung cancer. The current technique of video-assisted lung resection have various troublesome procedures as compared with conventional open thoracic surgery. We have designed a new thoracoscopic instrument as a ligation device. Between September 1997 and August 1999, 15 patients with early lung cancer underwent video-assisted lobectomy (VAL). In 5 patients, VAL was performed through skin incisions of 3 cm using this new device and at extraction of the resected lung the skin incision was elongated minimally (Group A). In 10 patients, a skin incision of 6-8 cm was made enough to perform VAL without the new device at the beginning of the operation (Group B). Total length of skin incisions (TLS) and total postoperative pleural discharge (TPD) were measured. TLS was 7.2 +/- 1.47 cm in group A, 11.9 +/- 4.50 cm in group B (p = 0.029). TPD was 492 +/- 256 ml in group A, 1.132 +/- 591 ml in group B (p = 0.032). TPD might be thought as an index of invasion of VAL and it was difficult to decrease TPD significantly. The new device made it possible to feel the ligature tension when the device was in touch with the chest wall. In a result, the device improved technical procedure of VAL and contributed toward less invasive surgery.

Evaluation Studies as Topic↗
PubMed2000

[Transaortic video-assisted thrombectomy in the left ventricular cavity after acute myocardial infarction].

In recent years much attention has been paid to a minimal invasive surgery even in the field of cardiac surgery. We have successfully treated a 59 year-old male who underwent transaortic video-assisted thrombectomy in the left ventricular cavity following acute myocardial infarction due to occlusion (No. 7) of the left descending coronary artery (LAD). After the LAD was recanalized by percutaneous transluminal coronary angioplasty (PTCA) and then stenting, this thrombectomy was carried out. Following initiation of cardiopulmonary support, thrombus in the left ventricular apex was safely removed by transaortic endoscopic guidance. This technique was useful especially for the patient with poor ventricular function due to acute myocardial infarction because of no left ventriculotomy. Endoscopic guidance technique is reported in detail.

Angioplasty, Balloon, Coronary↗
PubMed2000

Delineation of the frequently deleted region on chromosome arm 13q in B-cell non-Hodgkin's lymphoma.

The loss of a specific chromosomal region provides a clue to the elucidation of the putative tumor suppressor gene implicated in the pathogenesis and progression of tumors. To delineate the specific region(s) involved in lymphomagenesis, we performed a survey of loss of heterozygosity for 11 polymorphic microsatellite loci scattered on variable chromosome arms. We examined 20 primary lymphoma samples, including both indolent and aggressive B-cell non-Hodgkin's lymphoma (B-NHL) and Hodgkin's disease (HD), and found a significant number of B-NHLs with loss of genetic material on chromosome arm 13q at the RB1 locus (50%; 4 of 8 informative cases for the RB1 locus). To specify the 13q deletion and to narrow the critical deleted region, we examined the same 20 lymphomas by intensive microsatellite mapping analysis using 12 microsatellite markers, mapping from 13q12.3 to 13q14. We confirmed the frequent 13q14 deletion to be in the vicinity of the RB1 locus (50% of the informative NHLs for at least 1 of 12 microsatellite loci; 5 of 10 aggressive NHLs and 2 of 4 indolent NHLs, but none of 6 HDs) and determined a subchromosomal region deleted in lymphoma on 13q14 defined by D13S164-D13S273, which is an overlapped region frequently lost in chronic lymphocytic leukemia. Taken together, our data indicate that the 13q alterations are present in a wide variety of NHLs including both indolent and aggressive B-NHLs, suggesting that loss of genetic material at chromosome band 13q14 may play an important role in the formation or development of a wide variety of mature lymphoid malignancies.

Adult↗
PubMed2000

[Splenic natural killer cell activity is suppressed by ligation of unilateral mental nerve in rats].

It has been reported that surgical procedures and postoperative pain suppress immune activities of the patient. But it is not clear if chronic pain in a small area affects immune activities. We prepared rats with chronic neuralgia of the mental branch originating from the mandibular nerve (a division of the trigeminal nerve) and examined the change of splenic NK-cell activity. Surgical procedures to prepare rat models for the study were as follows: one mental nerve was exposed and ligated at the mental foramen in order to create hypersensitivity in the ipsilateral innervated area. Splenic NK-cell activity 3 weeks after the surgery was reduced significantly in the operation group than that of the sham-operation group and the non-operated control group. The result suggests that the immune functions are remarkably affected by chronic pain evoked in a limited area such as the area innervated by the mental nerve.

Animals↗
PubMed2000

Changes in microbial flora in neutropenic patients with hematological disorders after the Hanshin-Awaji earthquake.

The earthquake that struck the Hanshin-Awaji district on January 17, 1995, was one of the most destructive to occur in Japan. We analyzed the changes in microorganisms isolated from patients with hematological disorders in relation to this earthquake. We reviewed a total of 4137 microbial cultures obtained over 1-year periods before and after the earthquake. There were 123 neutropenic patients admitted during the study period (54 before the earthquake and 69 afterwards). No significant differences in clinical characteristics and underlying diseases were found between the 2 groups. Polynomial analysis revealed a significant increase in the isolation of Candida albicans, Candida glabrata, and Pseudomonas aeruginosa from sputum and stool cultures after the earthquake. These microorganisms increased markedly in patients from severe earthquake-damaged areas. In neutropenic patients with hematological disorders, microbial isolates changed significantly after the Hanshin-Awaji earthquake. These changes may have been related to physical and emotional stress, as well as to the deterioration of environmental factors such as food, air, and water.

Adolescent↗
PubMed2000

Alteration of tumor phenotypes of B16 melanoma after genetic remodeling of the ganglioside profile.

Gangliosides have been thought to be tumor markers of various neuroectoderm-derived cancers. However, their roles in malignant phenotypes of cancer cells are not well understood. We have performed the remodeling of ganglioside profiles of mouse melanoma B16 (B78 subline) by introducing GM2/GD2 synthase cDNA, and analyzed the phenotypic changes such as cell morphology, growth, adhesion and c-fos gene expression. Although newly expressed GM2 was clearly detected, GM2-positive transfectant cells showed rather reduced growth rates in vivo and in vitro, lower expression levels of c-fos gene and increased levels of cell adhesion to extracellular matrices compared to control cells. These results suggested that GM2 is involved in the regulation of cell-cell or cell-extracellular matrix interaction, and negatively control cell proliferation.

Animals↗
PubMed2000

Self-expandable vascular stent covered with polyurethane membrane: an experimental preliminary study of a placement in the thoracic descending aorta of a rabbit using endovascular intervention.

The effectiveness of self-expandable vascular endoprosthesis covered with polyurethane membrane for arterial substitution was examined in the descending thoracic aorta of a rabbit, followed by an observation period of 937 days. In this model there was no evidence of thrombus, aneurysmal formation, and/or infection. The self-expandable vascular stent covered with a polyurethane membrane showed long-term patency as well as excellent function, and the histological evaluation revealed endothelial cells covering all of the surface of the endoprosthesis, as was expected. Minimal intimal hyperplasia and no calcifica-tion were demonstrated in any portions. This study suggests that our newly designed self-expandable vascular stent covered with a polyurethane membrane could serve as a satisfactory vascular endoprosthesis with a good long-term patency for substitution. Furthermore, stenting using our model is a safe, simple technique, and an effective treatment for vascular remodeling.

Animals↗
PubMed2000

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (1998)].

The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. Ikemoto et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and analyzed some characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed. In these 18 institutions around the entire Japan, 532 strains of presumably etiological bacteria were isolated mainly from the sputa of 438 patients with lower respiratory tract infections during the period from October in 1998 to September in 1999. MICs of various antibacterial agents and antibiotics were determined against 85 strains of Staphylococcus aureus, 100 strains of Streptococcus pneumoniae, 96 strains of Haemophilus influenzae, 75 strains of Pseudomonas aeruginosa (non-mucoid strains), 6 strains of Pseudomonas aeruginosa (mucoid strains), 38 strains of Moraxella subgenus Branhamella catarrhalis, 26 strains of Klebsiella pneumoniae etc., and the susceptibilities of 517 strains were assessed except for those strains that died during transportation. S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 micrograms/ml (methicillin-resistant S. aureus: MRSA) accounted for 60.0%. Vancomycin (VCM) and arbekacin (ABK) showed the most potent activities against MRSA. But one of MRSA showed resistance to ABK with the MIC of 64 micrograms/ml. The sensitive strains of MRSA to VCM have decreased. The frequency of penicillin (PC)-intermediate S. pneumoniae (PISP) + PC-resistant S. pneumoniae (PRSP) have increased in 46.0% for 1998 comparatively from 30.9% of 1997's. But PRSP decreased, and PISP increased into 39.0% of 1998 years from 19.8% of 1997's. Panipenem (PAPM), imipenem (IPM) and faropenem (FRPM) showed the most potent activities against S. pneumoniae with MIC80s of 0.125 microgram/ml or below. Against H. influenzae and M. (B.) catarrhalis, almost all the drugs showed good activities. The sensitive strains of them against ceftazidime (CAZ) decreased in 1997, but those have increased in 1998. Inversely, the susceptibility of them against cefotiam (CTM) had been higher in 1997, but those have been lower in 1998. Tobramycin (TOB) showed the most potent activity against P. aeruginosa (both mucoid and nonmucoid strains). All drugs except ampicillin (ABPC) were active against K. pneumoniae. A quite few of K. pneumoniae showed low susceptibilities. Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. The examination of age distribution indicated that the proportion of patients with ages over 70 years was 48.6% of all the patients showing a slight increase in every year. About the proportion of diagnosed diseases as follows: Bacterial pneumonia was the most frequent with 40.2%. The ratio of it has increased slightly, and the increased rate was 10% in patients with ages over 70 years compared with the results in 1997. Chronic bronchitis have decreased slightly with 27.6% in 1998. Number of strains isolated from patients before administration of antibiotics were more than those after administration of them in chronic bronchitis, but these were almost same number in bacterial pneumonia. Administration of antibiotics has changed the results of the frequency of isolation of bacterial species. Bacterial isolations before administration of antibiotics were as follows: S. pneumoniae 26.7%, H. influenzae 23.8%, S. aureus 13.3% and M. (B.) catarrhalis 10.8%. The frequencies of S. aureus decreased after antibiotics administration over 15 days, but the frequencies of P. aeruginosa (both mucoid and non-mucoid) was not affected. The frequencies of P. aeruginosa was 45.5% after administration over 15 days. The frequencies of S. pneumoniae decreased upon administration of antibiotics, these were only 4.5% over 15 days. The frequencies of H. (

Anti-Bacterial Agents↗
PubMed2000

[Recent advances in colorectal cancer surgery].

Recent advances in colorectal cancer surgery have been made in improving the cure rate after surgery, the preservation of postoperative function, and the development of minimally invasive procedures. Indication for wide lymph node dissection in rectal cancer surgery is now limited to a smaller number of cases. Functional outcome is being improved thanks to the introduction of autonomic nerve preserving operations as well as the increasing number of sphincter preserving operations. Laparoscopic colectomy for cancer has been practiced for 7-8 years, and the advantages and disadvantages of this procedure are being clarified. Transanal endoscopic microsurgery (TEM) is a minimally invasive surgery for rectal tumors in early stages. The procedure is now overtaking the posterior surgical approach, which is used less and less in recent years. Future goals in colorectal cancer surgery are further improvements in the cure rate and the functional results. Minimally invasive surgery may become the established procedure after a careful assessment of its cure rate compared to the open surgical procedure.

Colorectal Neoplasms↗