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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 325 records · Page 18Linked to original sources
PubMed1997

A case of mosaic tetrasomy 12p (Pallister-Killian Syndrome) diagnosed prenatally: comparison of chromosome analyses of various cells obtained from the patient.

A pregnant woman was referred to our hospital at the 29th week of gestation with the symptom of polyhydramnios; diaphragmatic herniation of the fetus was suspected. Fetal chromosome anlaysis was performed using fibroblasts obtained by aminocentesis, and mosaicism of 46,XX and isochromosome of 12p were diagnosed. Out of 50 karyotyped cells, 19 (38.0%) showed the tetrasomy of the isochromosome of 12p. The mother vaginally delivered a baby girl who died just after delivery. The analysis of cord blood lymphocytes revealed only 0.5% incidence of tetrasomy of 12p. The incidence of tetrasomy was 8.0% for the placental chorionic villi, 48.0% for the fibroblasts obtained from the umbilical cord, and 70.0% for the skin fibroblasts. Thus, the diagnosis of Pallister-Killian Syndrome (PKS) is confirmed by mosaicism of i(12p), that is, the affected patients exhibit tissue-specific mosaicism, with the abnormal karyotype expression in limited lymphocytes, but marked in fibroblasts.

Adult↗
PubMed1997

Expression of optical diffusion coefficient in high-absorption turbid media.

The optical diffusion coefficient in a homogeneous turbid medium with high absorption was determined by steady-state measurements of the light transmission under the infinite-boundary condition. The intensity of the transmission was well described by the solution of the optical diffusion equation. Moreover, the optical diffusion coefficient D was given by a constant, (3 mu'(s))-1, where mu'(s) is the reduced scattering coefficient, up to the absorption coefficient of about 0.3 mu'(s). These results mean that attenuation by absorption only contributes to exponential attenuation along the optical path defined by the scattering coefficient and geometry of the system even in high-absorption turbid media such as the pathological living tissues of bleeding or haematoma.

Absorption↗
PubMed1997

Relationship between time-resolved and non-time-resolved Beer-Lambert law in turbid media.

The time-resolved Beer-Lambert law proposed for oxygen monitoring using pulsed light was extended to the non-time-resolved case in a scattered medium such as living tissues with continuous illumination. The time-resolved Beer-Lambert law was valid for the phantom model and living tissues in the visible and near-infrared regions. The absolute concentration and oxygen saturation of haemoglobin in rat brain and thigh muscle could be determined. The temporal profile of rat brain was reproduced by Monte Carlo simulation. When the temporal profiles of rat brain under different oxygenation states were integrated with time, the absorbance difference was linearly related to changes in the absorption coefficient. When the simulated profiles were integrated, there was a linear relationship within the absorption coefficient which was predicted for fractional inspiratory oxygen concentration from 10 to 100% and, in the case beyond the range of the absorption coefficient, the deviation from linearity was slight. We concluded that an optical pathlength which is independent of changes in the absorption coefficient is a good approximation for near-infrared oxygen monitoring.

Animals↗
PubMed1997

Macrophages in normal cycling human ovaries; immunohistochemical localization and characterization.

We evaluated the immunolocalization and characterization of macrophages in 28 normal cycling human ovaries. Two primary antibodies were used to detect the macrophages: PGM1, a general marker for macrophages, and 25F9 which is specific for phagocytosing macrophages. Spindle-shaped cells positive for PGM1 but negative for 25F9 were observed in the stroma (123.6 +/- 1.05 cells/10(-6) m2) and theca layer of the follicle (mean ranged from 22.61 to 53.79) and the number of these cells did not change throughout the cycle. After ovulation, PGM1 positive cells with ballooning bodies began to appear in the early corpus luteum (111.8 +/- 0.83). The number of these macrophages increased in the mid and late corpora lutea, and reached maximum in the early degenerating corpus luteum (1231.0 +/- 3.29). A lower number of PGM1 positive ballooning macrophages were observed in the atretic follicle (177.9 +/- 1.42). 25F9 positive cells were also observed among the PGM1 positive balloon-shaped cells. The number of cells double positive for 25F9 and PGM1 was observed in the mid corpus luteum (44.6 +/- 0.46), increased in the late corpus luteum and early degenerating corpus luteum, and reached plateau in the late degenerating corpus luteum (549.0 +/- 5.82). A lower number of these double positive macrophages were also observed in the atretic follicle (64.8 +/- 0.36). The ratio of 25F9 to PGM1 positive cells increased in parallel with ageing of the corpus luteum (0.19 in the mid corpus luteum, 0.39 in the late corpus luteum, and 0.37 in the early degenerating corpus luteum), and the great majority of PGM1 positive cells were also immunopositive for 25F9 in the late degenerating corpus luteum (0.81). These results suggest that in normal cycling human ovaries, macrophages are mainly involved in luteal regression as scavengers.

Antibodies, Monoclonal↗
PubMed1997

Rhodamine 800 as a probe of energization of cells and tissues in the near-infrared region: a study with isolated rat liver mitochondria and hepatocytes.

To examine the feasibility of optical monitoring of cellular energy states with tissue-transparent near-infrared (NIR) light, the absorption and fluorescence characteristics of Rhodamine 800 in isolated rat liver mitochondria and hepatocytes were investigated. When the dye was incubated with isolated mitochondria, a large red shift of the absorption spectra and quenching of the fluorescence intensity were observed. The absorbance difference at 730 minus 685 nm, or at 730 minus 800 nm, and the fluorescence intensity measured at 692 nm varied linearly with the mitochondrial membrane potential. The spectral changes observed could be explained in terms of the potential-dependent uptake of the dye from the buffer solution into the mitochondrial matrix. The respiration control ratio and oxygen consumption rate were not affected by the addition of Rhodamine 800 at concentrations lower than 5 microM, which was the concentration range mostly employed throughout the present study. In a suspension of hepatocytes, the red shift and fluorescence quenching of Rhodamine 800 characteristic of energized mitochondria were also observed, and these changed to those of the buffer solution with the addition of an uncoupler under normoxia. At the early stage of anoxia, within about 5 min, when cytochrome oxidase was completely reduced, hepatocytes were concluded to be in the fully energized state, since the optical characteristics of Rhodamine 800 were the same as those of energized mitochondria. On the basis of these in vitro data, Rhodamine 800 is concluded to be a possible NIR-active contrast agent, that can be used to monitor the energy states of living tissues, in addition to the tissue oxygenation states, by the use of near-infrared spectrophotometry (NIRS) without harmful effects.

Adenine↗
PubMed1997

Distribution of a synthetic protease inhibitor in rat pancreatic acini after supramaximal secretagogue stimulation.

Protease inhibitors may have a beneficial effect in acute pancreatitis. The effects of E3123, a new low molecular weight protease inhibitor, on the ultrastructure of isolated pancreatic acini were examined using transmission electron microscopy. Acini supramaximally stimulated with cerulein (10(-8) M) formed large cytoplasmic vacuoles similar to those generated in the cerulein-induced in vivo model of pancreatitis. Pretreatment of isolated acini with E3123 significantly reduced the size and number of vacuoles associated with cerulein treatment. The distribution of 3H-E3123 in acinar cells was examined using a pulse-chase protocol and electron microscopic autoradiography. Cellular levels of 3H-E3123 increased about 30-fold in acinar cells treated with cerulein (10(-8) M) compared to unstimulated controls. In cerulein-treated acini examined after a 5-min chase, 47.4% of the autoradiographic grains were associated with the rough endoplasmic reticulum and 13.2% were associated with zymogen granules. After 30 min of incubation, the grains associated with the endoplasmic reticulum decreased to 18.5% but increased to 26.3% over zymogen granules. Thus, E3123 is taken up by the acinar cell and follows a cellular itinerary similar to that of newly synthesized secretory proteins. One potential conclusion from these studies is that the ability of E3123 to reduce the formation of vacuoles in supra-maximally stimulated acini may be due to its inhibition of proteases within the secretory pathway.

Amylases↗
PubMed1997

Usefulness of a mouse myelin basic protein promoter for gene therapy of malignant glioma: myelin basic protein promoter is strongly active in human malignant glioma cells.

We have searched for suitable promoters to regulate the expression of suicide genes for use in gene therapy. We have shown that the 1.3-kb fragment of the mouse myelin basic protein (MBP) promoter region initiates transcription in mouse glioma cells more efficiently than glial fibrillary acidic protein (GFAP) or myelin proteolipid protein (PLP) promoter. Among three different lengths of the MBP promoter, the shortest (256-bp) core promoter region initiates transcription as efficiently as 650-bp or 1.3-kb MBP promoter lengths in RSV-M glioma cells. To assess the suitability of the MBP promoter for use in clinical trials of malignant glioma gene therapy, we also had to show that it (the 1.3-kb length in this case) is effective in human glioma cells, as well as in murine glioma cells. The activity of the MBP promoter is much higher than that of GFAP or PLP promoter in most human glioma cells, suggesting that the MBP promoter would be best for directing toxic gene expression in gene therapy for patients with malignant glioma. Human glioma cells in which the MBP promoter was strongly active were sensitive to ganciclovir when they were transduced with MBP promoter/herpes simplex virus thymidine kinase gene-bearing retroviruses. In conclusion, retrovirus-targeted gene therapy for malignant glioma using this MBP promoter is a promising candidate for clinical trials.

3T3 Cells↗
PubMed1997

Evidence of hydroxyl free radical generation by calcium overload in rat myocardium.

Although calcium (Ca2+) is important in cardiac dysfunction and has also been reported as a source of oxidative toxicity, the connection between Ca2+ overload and oxygen free radicals in the myocardium is not clear. We have investigated whether Ca2+ overload generates hydroxyl free radicals in rat ventricle. HPLC with electrochemical detection was used to measure the levels of 2,3- and 2,5-dihydroxybenzoic acid (DHBA) formed when the hydroxyl free radical reacts with salicylate. Ringer's solution containing salicylic acid (0.5 nmol microL-1 min-1) was infused through a microdialysis probe in the region of the left anterior descending coronary artery of the rat ventricle. A positive linear correlation was obtained between Ca2+ and hydroxyl free radical formation trapped as 2,3-DHBA (r2 = 0.976) and 2,5-DHBA (r2 = 0.982) in the myocardial dialysate. The administration of ouabain (1 mg kg-1, i.v.), a Ca2+ elevator, into the femoral vein significantly increased the level of 2,3- and 2,5-DHBA. These results indicate that Ca2+ overload generates hydroxyl free radicals in rat heart.

Animals↗
PubMed1997

Redox behavior of cytochrome oxidase in the rat brain measured by near-infrared spectroscopy.

Using near-infrared spectroscopy, we developed a new approach for measuring the redox state of cytochrome oxidase in the brain under normal blood-circulation conditions. Our algorithm does not require the absorption coefficient of cytochrome oxidase, which differs from study to study. We employed this method for evaluation of effects of changes in oxygen delivery on cerebral oxygenation in rats. When fractional inspired oxygen was decreased in a stepwise manner from 100 to <10%, at which point the concentration of oxygenated hemoglobin ([HbO2]) decreased by approximately 60%, cytochrome oxidase started to be reduced. Increases in arterial PO2 under hyperoxic conditions caused an increase in [HbO2], whereas further oxidation of cytochrome oxidase was not observed. The dissociation of the responses of hemogloblin and cytochrome oxidase was also clearly observed after the injection of epinephrine under severely hypoxic conditions; that is, cytochrome oxidase was reoxidized with increasing blood pressure, whereas hemoglobin oxygenation was not changed. These data indicated that oxygen-dependent redox changes in cytochrome oxidase occur only when oxygen delivery is extremely impaired. This is consistent with the in vitro data of our previous study.

Animals↗
PubMed1997

Effects of pectin on jejunal and ileal morphology and ultrastructure in adult mice.

The effects of pectin on jejunal and ileal morphology and ultrastructure were studied using adult male mice fed a semisynthetic diet containing 8% (w/w) cellulose or pectin for 30 days. No significant differences in the jejunal villus height between the 2 groups were found, but the jejunal crypt depth, and both the ileal villus height and crypt depth of the mice fed the pectin diet were significantly greater than those of the mice fed the cellulose diet. There were evident ultrastructural differences in the jejunal absorptive cells between 2 dietary groups: numerous intercellular spaces were observed in the jejunal absorptive cells of the mice fed the pectin diet, but not the cellulose diet. Moreover, the ileal absorptive cells of the mice fed the pectin diet contained numerous peroxisomes, whereas there were few in these cells of mice fed the cellulose diet. The functional characteristics of the ileum of the mice fed the pectin diet might be different from those fed the cellulose diet.

Animals↗
PubMed1997

Histological observations of the adhesion and endocytosis of calcium oxalate crystals in MDCK cells and in rat and human kidney.

Adhesion and/or endocytosis of calcium oxalate crystals to the three kinds of tubular cells (Madin-Darby canine kidney (MDCK) cells, rat and human kidney) were demonstrated morphologically to presume the initial formation of kidney stone. After removal of the nonadhesion crystals, the cells were subsequently recultured in the vertical position. At various times thereafter, the interactions between COM crystals and MDCK cells were evaluated morphologically by SEM. COM crystals adhered to the surface of MDCK cells immediately, and the crystals were then endocytosed. The microvilli of the cells appeared to play an important role in these processes. At later times, some complexes that consist of aggregated calcium oxalate crystals and cell debris were observed sporadically. Kidney tissues were obtained from male Sprague-Dawley rats which were injected with sodium oxalate intraperitoneally. Experimentally induced calcium oxalate crystals were evaluated histologically using polarized light microscopy. Some crystals in the cortical portion were attached to the tubular epithelium or internalized into the luminal membrane. Whereas in the papilla, the aggregated crystals were observed lying free from the degenerated tubular lumen along with the cell debris. Human kidney tissues were obtained from 38 patients with calcium oxalate nephrolithiasis who underwent nephrolithotomy or partial nephrectomy before the era of ESWL. The specimens were examined for calcium crystals within the tubular lumen, attached to the tubular walls or internalized into the tubular cells, by polarized light microscopy. Approximately 50% of the specimens observed crystals attached to the tubular cell epithelium and some of them were seen inside the tubular cells. In conclusion, crystal-cell interaction resulted in movement of crystals from the lumen into the cells by an action of microvilli from the results of MDCK cells. However, it was not clear from the results in rats or human kidney tissue that crystal adhesion and/or endocytosis might be vital in the crystal growth in the kidney.

Animals↗
PubMed1997

Gypsophilin, a new type 1 ribosome-inactivating protein from Gypsophila elegans: purification, enzymatic characterization, and subcellular localization.

Gypsophila elegans contains a new type 1 ribosome-inactivating protein, which we named gypsophilin. The protein was purified to apparent homogeneity by (NH4)2SO4 fractionation, ion-exchange chromatography, and adsorption chromatography. The protein was found to have a molecular mass of 28.0 kDa and a pI of about 10.1. It does not contain glycosidic linkages. The sequence of the N-terminal 22 amino acids of the protein shows a close relationship to other RIPs. The enzyme strongly inhibits protein synthesis in a rabbit reticulocyte lysate and depurinates 28S rRNA in rat liver ribosomes in a manner identical to that of ricin A-chain and other RIPs. Using a direct method for the measurement of the RNA N-glycosidase activity, the substrate specificity of gypsophilin was identified. EC50 of the protein for ribosomes of rat liver, wheat germ, and E. coli was 39.8 pM, 0.24 nM, and 0.82 microM, respectively. Gypsophilin may be one of the most active RNA N-glycosidases among the RIPs known to date. Immunoelectron microscopic localization of gypsophilin in the leaves shows that the protein is accumulated densely in the intercellular spaces and is also distributed within vacuoles in the cytoplasm.

Amino Acid Sequence↗
PubMed1997

HLA antigens in patients with severe preeclampsia.

The distribution of human leucocyte antigens (HLA) was analyzed in 35 patients with severe preeclampsia and compared with that in the general population in the Niigata district of Japan. The frequency of patients with HLA CW7 was significantly higher than that of the general population of this area (p < 0.05, Chi-square test). The frequency of those with HLA-DR6 (DR6, DR13 and DR14) was also significantly greater compared with the general population (P < 0.05, Chi-square test), while that of those with DR4 was significantly lower (P < 0.05, Chi-square test). The compatibility of HLA antigens in spouses was also analyzed in 20 patient couples and 26 normal fertile couples, and there was no significant difference. Thus it is suggested that HLA antigen systems might be involved in the genesis of preeclampsia.

Female↗
PubMed1997

Alterations of lymphocyte subsets in patients with recurrent fetal wastage positive for antiphospholipid antibodies treated with Chinese herbal medicine.

The alterations of peripheral blood lymphocyte subsets were sequentially analyzed in patients with recurrent fetal wastage who were treated with the Chinese herbal medicine, Sairei-to (Chan ling-Tan) for positive antiphospholipid antibodies to analyze the underlying mechanisms of the therapy. The titer of antiphospholipid antibodies was significantly decreased by administration of Sairei-to at one and two months after commencement of treatment and in the newly pregnant state compared with that before administration. The percentage of CD19-positive cells significantly decreased at two months after commencement of Sairei-to treatment and at the newly pregnant state compared with that before administration in successful pregnancies. The percentage of CD4-positive cells significantly increased two months after commencement of Sairei-to treatment compared with that before administration in both successful pregnancies and total cases. The CD4/CD8 ratio was increased significantly after two months administration of Sairei-to in both successful pregnancies and total cases. Thus, it is suggested that the administration of Sairei-to might induce the predominance of CD4-positive cells in parallel with the suppression of antiphospholipid antibodies. Moreover, the suppression of CD19-positive cells (B cells) was induced by administration of Sairei-to which might be involved in successful continuation of pregnancy in the patients.

Abortion, Habitual↗
PubMed1997

Immunosuppressive therapy for recurrent aborters with positive antiphospholipid antibodies and alteration of 6ketoPGF1 alpha/TXB2 ratio.

Twelve women (13 pregnancies) with antiphospholipid antibodies (APA) who had suffered from two or more recurrent spontaneous abortions or fetal deaths and had successful pregnancy outcomes after immunosuppressive therapy were studied. APA titers were determined by enzyme-linked immunosorbent assay against cardiolipin, phosphatidyl serine and phosphatidyl inositol. Plasma levels of 6ketoprostaglandin F1 alpha (6ketoPGF1 alpha) and thromboxane B2 (TXB2) were determined by radioimmunoassay. All of the 13 pregnancies resulted in term delivery. None of the 13 patients suffered from pregnancy-induced hypertension, and only one showed intrauterine growth retardation. A significant decrease of APA titer was observed after immunosuppressive therapy. The 6ketoPGF1 alpha/TXB2 ratios before the therapy, after it and at the 1st, 2nd and 3rd trimesters of pregnancy were 0.62 +/- 0.398, 0.88 +/- 0.106, 0.84 +/- 0.550, 1.25 +/- 0.834 and 0.67 +/- 0.413, respectively. The ratio at the 2nd trimester was significantly higher than that before the therapy (P < 0.05, paired t-test, n = 9). The results indicate that the immunosuppressive therapy affected the physiological balance between thromboxane A2 and prostacyclin, and improved clinical symptoms such as recurrent fetal wastage.

6-Ketoprostaglandin F1 alpha↗
PubMed1997

Symptomatic aortic regurgitation after Blalock-Taussig shunt in tetralogy of Fallot with bicuspid aortic valve.

We report here a case of a premature baby with tetralogy of Fallot and bicuspid aortic valve. After the successful completion of the Blalock-Taussig (BT) shunt, severe aortic valve regurgitation (AR) appeared, although it was trivial preoperatively. Severe postoperative heart failure was induced by progression of the AR. Postoperative echocardiography revealed that the progression of the AR was provoked by appearance of prolapse of the cusp as the result of rapid increase of blood flow through the aortic valve after the BT shunt. We propose that, in planning the BT shunt for patients with tetralogy of Fallot, preoperative examinations for a possible bicuspid aortic valve should be done and postoperative precaution considering possible appearances of severe AR and congestive heart failure will be necessary.

Anastomosis, Surgical↗
PubMed1997

Changes in left ventricular diastolic filling patterns before and after the closure of the ductus arteriosus in very-low-birth weight infants.

To evaluate serial changes in left ventricular diastolic filling patterns in preterm infants, we performed echocardiographic examinations in 18 very-low-birth weight infants and 20 fullterm infants before and after the closure of the ductus arteriosus. In the fullterm infants, the ductal closure induced significant decreases in the peak velocity and flow velocity integral of early diastole, first third filling fraction, and mitral stroke volume. In the preterm infants, by contrast, there were significant increases in the flow velocity integral of early diastole, first third filling fraction, and mitral stroke volume after the ductal closure. No differences following the ductal closure were found in the atrial phase of filling and peak filling rate normalized to stroke volume in either group. When the ductus arteriosus was open, essentially the same left-to-right shunting of the ductus arteriosus was detected in both preterm and fullterm infants, but the Doppler flow patterns of the patent foramen ovale were different: the fullterm infants had a single flow peak mainly during ventricular late systole and early diastole, but the preterm infants had two or three flow peaks with nearly equal amplitudes lasting from ventricular systole to diastole, which resembled the Doppler flow pattern of atrial septal defect. Only a faint Doppler flow signal of the foramen ovale was observed after the ductus arteriosus closed. Our results obtained from the preterms suggest that the left-to-right shunt through the foramen ovale may be one important factor to alter the Doppler transmitral filling patterns during the fetal to neonatal cardiovascular changes.

Ductus Arteriosus↗