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Biomedical subjects

Y Okuno

Publications and source records attributed to Y Okuno.

At least 163 records · Page 9Linked to original sources
PubMed1992

Development of a mandibular tracking device with six degrees of freedom using optoelectronic system.

The purpose of this study was to develop a prototype handy mandibular tracking device with six degrees of freedom using the optoelectronic kinematic data acquisition system and to evaluate its accuracy. The system consisted of the light-weight sensor part mounted on the mandibular incisor portion and two 2-D PSD cameras positioned in front of the patient. On the sensor part, three light emitting diodes (LEDs) were attached in triangular form. Displacements of the sensor part were detected by two cameras, transformed into electric signals, and sampled by A/D converter in a desktop computer. Since the overall accuracy of this system was about 0.03 mm in the displacement and 0.06 degrees in the rotation angles, this system was proven to be capable for the wide range of clinical application.

Humans↗
PubMed1992

Three dimensional shape measurement system for residual ridges.

It is very important for design and construction of complete dentures to evaluate the condition of residual ridges of edentulous patients objectively and precisely. The authors have been developing a shape measurement system for residual ridges. In this study, the outline of the system is described and the accuracy of the system is evaluated. The system consists of a high precision laser displacement meter, a working table and its controller, and a personal computer. The working table, on which a plaster model is placed, can move until the end of the moving range at a speed of 0.7 mm/sec. The height of the plaster model was measured intermittently with a frequency of 7 points/sec. To determine the accuracy of this system, experimental plaster models, which simulated the simplified shape of residual ridge, were measured and analyzed. The measurement error was 2.5%, which seemed to be highly accurate. The accuracy of the measurement decreased with the darkness of the color of the plaster model.

Alveolar Bone Loss↗
PubMed1992

Effects of heat treatment on mechanical properties of base metal wrought wire clasps.

The purpose of this study is to determine the effects of heat treatment and soldering on the change of shape and mechanical properties of cobalt-chromium-nickel alloy wrought wire clasps. The change of distance between the tips of the clasp arm was measured and mechanical properties were examined using the bending test. The following results were obtained. 1) By heat treatment at 500-700 degrees C for 10 minutes, bending rigidity and deflection at the proportional limit of the clasp arm increased significantly (p < 0.01), while permanent deformation after the bending test decreased considerably (p < 0.01). Concerning the deformation of clasp arms by heating, the distance between clasp tips increased remarkably above 500 degrees C (p < 0.01). 2) These mechanical properties of clasp arms were improved both by electric resistance soldering with silver solder and by heat treatment at 500 degrees C for 10 minutes after soldering. From these results, it was concluded that electric resistance soldering and adequate heat treatment were very effective to improve the mechanical properties of the clasp arm, especially to increase the deflection at the proportional limit and reduce the permanent deformation.

Chemical Phenomena↗
PubMed1992

Influence of dimensional factors and heat treatment on permanent deformation of wrought wire clasps.

The purpose of this study is to examine the fatigue profiles of wrought wire clasps during the clinical use. Cobalt-chromium-nickel alloy wires were bent into circular beams, which dimensions and fabrication methods were similar to the clinical cases. Deflections of 0.5 mm in a normal direction were applied 10,000 times to the tips of clasp arm and permanent deformations were measured. The following results were obtained. 1) The clasp arms with larger cross sectional diameter, shorter length and smaller radius of curvature showed larger amounts of permanent deformation. 2) The amounts of permanent deformation of the clasp arm remarkably decreased by electric resistance soldering and decreased further more by heat treatment at 500 degrees C for 10 minutes after soldering regardless of the number of deflection. From the results of this study, it was concluded that dimensional factors and heat treatment influenced the permanent deformation of the wrought wire clasps remarkably. Therefore, considering these factors, wrought wire clasps could be designed to reduce permanent deformation.

Chemical Phenomena↗
PubMed1992

Altered expression of protein kinase C in adult T-cell leukemia cells.

Protein kinase C (PKC) has been shown to be involved in the mitogenic response and in oncogenic cell transformation in many experimental models. We analyzed the expression of PKC in both highly purified leukemic T cells freshly isolated from adult T-cell leukemia (ATL) patients and control T lymphocytes obtained from healthy volunteers. PKC activity was decreased in the ATL cells as compared with the control T cells. Cytosolic PKC activity in the ATL cells was remarkably decreased, whereas particulate membrane PKC activity was similar to the control level. The percentage of PKC activity in the particulate fraction was 34% in the ATL cells and 19% in the control cells. Regarding the altered subcellular localization of PKC activity, phorbol ester-induced translocation of cytosolic PKC was inhibited in some ATL cases. Similarly to the decrease in PKC activity, there was a decrease in the expression of the major PKC isozymes II(beta) and III(alpha) in ATL cells. These results suggest impaired regulation of PKC expression in ATL as well as in many experimental cancers.

Adult↗
PubMed1992

[A comparison of the effects of omeprazole with those of ranitidine on intragastric pH and volume in patients for elective surgeries].

This study compared the effect of omeprazole with those of ranitidine on intragastric secretion during perioperative period. Thirty-one patients were randomly allocated to three groups. Each group received either omeprazole, ranitidine orally or one on the night before surgery. Intragastric pH and volume were measured after induction of anesthesia. Omeprazole group and ranitidine group had a higher mean pH than control group (P less than 0.01). None of the omeprazole group had an aspirate of pH lower than 2.5. One patient (10%) in the ranitidine group and five patients (50%) in the control group and five patients (50%) in the control group had aspirates of pH lower than 2.5. Mean gastric volume was not significantly different among these groups. A single dose of omeprazole 20 mg significantly decreased the number of patients at risk of aspiration pneumonitis.

Gastric Acid↗
PubMed1992

[Reactive histiocytosis during initial remission induction therapy for acute myeloblastic leukemia].

Six of 14 patients with acute myeloblastic leukemia (AML) complicated reactive histiocytosis during initial remission induction therapy. All six patients had a high fever without signs of infection during initial chemotherapy, and periods of myelosuppression were prolonged. Histiocytes with a mature appearance, some of which phagocyted erythrocytes, thrombocytes or neutrophils, increased in the bone marrow. All of 3 patients tested showed high serum levels of ferritin. Two of 3 patients treated with 125 mg/day methylprednisolone achieved complete remission. In the remaining 3 patients, one patient achieved complete remission, but the others died of fungal pneumonia or sepsis. Thus, reactive histiocytosis is one of the severe complications in patients with AML undergoing chemotherapy.

Adult↗
PubMed1992

Acquisition of growth autonomy and tumorigenicity by an interleukin 6-dependent human myeloma cell line transfected with interleukin 6 cDNA.

In human multiple myeloma, an autocrine growth mechanism through interleukin 6 (IL-6) has been advocated. However, growth of myeloma cells in vitro is poor except for established cell lines, and IL-6 autocrine growth is quite rare in myeloma cell lines. In the present study, we devised a model of IL-6 autocrine growth in vitro by transfecting IL-6 cDNA into a human myeloma cell line that had a proliferative response to IL-6 but did not produce IL-6. After IL-6 transfection, the cells proliferated in culture media without IL-6, and their growth rate was elevated at higher cell densities. IL-6 was detected by enzyme-linked immunosorbent assay in the culture media of the transfectants. IL-6 mRNA was distinctly expressed in these cells when analyzed by Northern blotting. The growth of the transfectants was definitely inhibited by anti-IL-6 or anti-IL-6 receptor monoclonal antibodies. Furthermore, the transfectants were successfully transplanted to nude mice. These results indicate that the myeloma cells obtained growth autonomy in vitro through IL-6 and tumorigenicity in vivo, after IL-6 transfection.

Animals↗
PubMed1991

Analysis of abnormal expression of g-csf gene in a novel tumor cell line (KHC 287) elaborating G-CSF, IL-1 and IL-6 with co-amplification of c-myc and c-ki-ras.

We established a human carcinoma cell line (KHC 287) from a patient with large-cell-typing lung carcinoma associated with marked leukocytosis. The culture supernatant of KHC 287 cells promoted granulocytic colony formation of human bone-marrow cells in semi-solid culture. Colony formation was almost completely suppressed by treatment of the supernatant with a monoclonal anti-granulocyte colony-stimulating factor (G-CSF) antibody. Not only G-CSF but also interleukin-1 alpha (IL-I alpha), IL-I beta and IL-6 were detected in the culture supernatant by an ELISA method. Northern blot analysis of KHC 287 cells revealed distinct expression of these cytokine genes. Southern blot hybridization of KHC 287 DNA showed 20- and 40-fold co-amplification of c-myc and c-ki-ras, respectively. The chloramphenicol acetyl transferase (CAT) activity was distinctly enhanced in the KHC 287 cells which were transfected with the 360 bp upstream region of G-CSF gene inserted into pSV00CAT, but not in non-G-CSF-producing tumor cell lines. These results suggest that overproduction of the transactivating factor(s) which binds to the 360 bp of the G-CSF upstream region is responsible for the abnormal expression of G-CSF gene in KHC 287 cell line.

Base Sequence↗
PubMed1991

Estimation of interleukin 6 production by reverse transcriptase-polymerase chain reaction in four human myeloma cell lines.

Although an autocrine growth mechanism through interleukin 6 has been advocated in human myeloma cells, reports of IL-6 production by cells from established myeloma cell lines are rare. In the present study, we examined whether or not a minute amount of interleukin 6 is produced in 4 human myeloma cell lines. IL-6 production was not detected in any of the 4 lines by enzyme immunoassay, bioassay with two interleukin 6-dependent murine hybridoma cell lines and Northern hybridization. However, we detected interleukin 6 mRNA in one (U266) of the 4 lines by the reverse transcriptase-polymerase chain reaction. Nevertheless, the proliferation of all 4 lines was not inhibited by an anti-interleukin 6 antibody. These results suggest that autocrine stimulation by interleukin 6 is not involved in the majority of human myeloma cell lines.

Base Sequence↗
PubMed1991

Increased insulin-insensitive glucose transport in polymorphonuclear leukocytes from non-insulin-dependent diabetic patients.

We studied the transport rate of a non-metabolizable hexose analogue, 3-O-methyl-D-glucose, in polymorphonuclear leukocytes (insulin-insensitive cells) from patients with untreated non-insulin-dependent diabetes mellitus. The mean glucose transport rate was significantly elevated in the diabetic patients compared with healthy controls (13.3 +/- 3.7 vs 10.4 +/- 2.5 fl/cell.sec, mean +/- SD, p less than 0.01). In the diabetic subjects, glucose transport rates were positively correlated with HbA1c levels (r = 0.563, p less than 0.01) but had no relations with ambient plasma glucose concentrations. Short-term incubation with 20 mM D-glucose had no effect on glucose transport in those cells. When glucose transport rates, HbA1c and fasting plasma glucose levels were simultaneously measured at weekly intervals over a four-week period in three diabetic subjects, the alterations in transport rates generally paralleled the changes observed in HbA1c levels rather than plasma glucose concentrations. It can be concluded that unlike insulin-sensitive cells such as adipocytes and muscle, glucose transport in human polymorphonuclear leukocytes, which are insulin insensitive cells, is increased in patients with non-insulin-dependent diabetes mellitus. Long-term, not short-term, derangement of glucose metabolism seems to be associated with increased glucose transport rate found in those patients.

Adult↗
PubMed1991

Co-production of interleukin-1 and interleukin-6 in tumor cell lines elaborating colony-stimulating factors.

Six carcinoma cell lines elaborating colony-stimulating factors (CSFs) were examined by enzyme-linked immunosorbent assay and Northern blotting to determine whether or not they co-produced interleukin-1 alpha (IL-1 alpha), IL-1 beta and IL-6. All 6 cell lines were co-producers; IL-1 alpha was produced in all 6, IL-6 in 5 and IL-1 beta in 3 of them. These results indicate that IL-1 and IL-6 are commonly co-produced in CSF-producing tumors.

Colony-Stimulating Factors↗
PubMed1991

Megakaryocyte potentiating activity of IL-1, IL-6 and GM-CSF as evaluated by their action on in vitro human megakaryocytic colonies.

We examined whether recombinant cytokines enhance the in vitro platelet production of interleukin-3 (IL-3)-induced human megakaryocytic colonies (Meg-colony). We classified Meg-colonies into four categories based on platelet production during in situ observation on day 14: type 0, absence of cytoplasmic processes in a colony; type 1, one to three processes in at least one megakaryocyte in a colony; type 2, four to eight processes; type 3, more than nine processes or division of cytoplasm. Type 3 colonies were considered to be platelet-producing. In control cultures, type 1 Meg-colonies were dominant, followed by type 2, type 3 and type 0. Of the cytokines added at the initiation of culture, interleukin-1 alpha (IL-1 alpha), interleukin-6 (IL-6), and granulocyte/macrophage colony stimulating factor (GM-CSF) significantly increased the number of colonies. Furthermore, these three cytokines significantly elevated the proportion of type 3 colonies. Interleukin-4 (IL-4), granulocyte-CSF, macrophage-CSF and erythropoietin did not affect the colony count or distribution of colony type. IL-1 alpha, IL-6 and GM-CSF also significantly elevated the proportion of type 3 colonies, even when added to the culture on days 8 or 11. These results indicate that IL-1 alpha, IL-6 and GM-CSF promote platelet production of in vitro Meg-colonies.

Blood Platelets↗
PubMed1991

Total and regional bone mineral content in patients with non-insulin dependent diabetes mellitus.

Total body bone mineral content and bone mineral content in various body sites were measured by dual-photon absorptiometry in 103 patients with non-insulin-dependent diabetes mellitus (NIDDM) and the findings were compared with those for 214 non-diabetic control subjects matched for age and body weight. Neither total body bone mineral content (TBBM) nor the bone mineral density of the third lumbar vertebra (L3 BMD) in the diabetic subjects differed from the values in control subjects of either sex, but the values were significantly decreased in patients diseased for at least five years when compared with control subjects. Regional bone mineral measurement showed prominent bone loss in the truncal site, but no reduction in bone mass was found in the head, pelvis, arms, or legs in either male or female patients. These results suggest that reduced TBBM and L3 BMD are associated with duration of the disease and that a site-specific bone defect is present in NIDDM.

Adult↗
PubMed1991

Calcium metabolism in diabetes mellitus.

Calcium metabolism was studied in patients with diabetes mellitus. Information on the dietary intake of major nutrients was gathered from 23 non-insulin-dependent diabetic patients, 42 insulin-dependent diabetic patients and 245 nondiabetic patients under hemodialysis through a questionnaire. A calcium absorption test was performed, using an isotopic technique, in 11 non-insulin-dependent diabetic patients and 4 age-matched healthy subjects. Parathyroid function was examined, using oral phosphate loading, in 6 diabetic patients and 6 age-matched control subjects. The daily dietary intake of calcium in the non-insulin-dependent diabetic patients (602 +/- 52 mg) was up to the average daily nutritional requirement (600 mg). The calcium absorption rate in these patients (54.4 +/- 13.9%) was similar to that in the healthy subjects (50.1 +/- 5.4%). The response of parathyroid hormone to phosphate loading was significantly reduced in the diabetic patients compared to the control subjects. The results suggest that calcium homeostasis in diabetic patients with normal renal function is almost conserved, despite the decreased response of parathyroid hormone to phosphate loading.

Administration, Oral↗
PubMed1991

Identification of colony-stimulating factor activity in patients with malignant tumors associated with excessive leukocytosis.

We have tried to demonstrate and identify colony-stimulating factor (CSF) activity in the plasma, pleural fluid, ascites or culture supernatant of tumor cells in 11 patients with malignant tumors associated with unexplained persistent leukocytosis. The specimens were treated with anti-granulocyte (G)-CSF or anti-granulocyte/macrophage (GM)-CSF monoclonal antibodies, then added to GM-progenitor (CFU-GM) cultures without exogenous CSFs. In all patients, untreated specimens generated CFU-GM-derived colonies, and colony formation was clearly inhibited by only one of the two antibodies, indicating the presence of either G-CSF or GM-CSF in the specimens. Furthermore, we measured the concentrations of G-CSF or GM-CSF in the specimens using an enzyme-linked immunosorbent assay, and confirmed the results by CFU-GM assay. Two patients were shown to have GM-CSF-producing tumors, while the other patients were G-CSF-producing. These assays are useful in identifying CSF activity in patients with CSF-producing tumors.

Aged↗
PubMed1991

Solitary pelvic kidney: an incidental case.

We report a case of solitary pelvic kidney. This uncommon condition was detected incidentally and diagnosed with intravenous pyelography (IVP), computed tomography (CT), and retrograde pyelography (RP).

Adolescent↗