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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 541 records · Page 30Linked to original sources
PubMed1996

Granulosa cells express integrin alpha 6: possible involvement of integrin alpha 6 in folliculogenesis.

To identify differentiation antigens of granulosa cells, we have raised two monoclonal antibodies against porcine granulosa cells (POG-2 antibody) and human granulosa cells (OG-1 antibody). Analysis of N-terminal amino acid sequences of purified OG-1 and POG-2 antigens revealed that they were identical to human integrin alpha 6 and its porcine homolog, respectively. An immunohistochemical study showed that integrin alpha 6 was highly expressed on granulosa cells in preovulatory follicles in the human ovary, whereas it was highly expressed on granulosa cells in small follicles in the porcine ovary. As a common characteristic of integrin alpha 6 expression in both ovaries, granulosa cells located in inner layers, which are not in contact with the basal lamina, expressed integrin alpha 6 on the cell surface. This expression profile suggests that the interaction between integrin and extracellular matrices occurs in the granulosa cells located in inner layers. This cell surface interaction is reported to modulate soluble signals to the cells. Since the expression of integrin alpha 6 on inner-layer granulosa cells is related to stages of differentiation, this interaction may be involved in folliculogenesis.

Animals↗
PubMed1996

Food antigen activates intraepithelial and lamina propria lymphocytes in food-sensitive enteropathy in mice.

Morphologic and immunologic changes in the gut mucosa of food-hypersensitive mice, from a study model generated by feeding ovalbumin (OVA) to female BALB/c mice after intraperitoneal injection of cyclophosphamide (CY), were investigated in an effort to clarify the mechanisms of food-sensitive enteropathy. Villous atrophy, crypt hyperplasia, and increased numbers of intraepithelial lymphocytes (IEL) were confirmed in the antigen-challenged OVA-sensitive mice as seen in food-sensitive enteropathy in humans, whereas no significant morphologic changes were observed in the nontreated control group or groups treated with OVA or CY alone. IEL and lamina propria lymphocytes (LPL) were isolated from the intestinal mucosa before and after the antigen challenge, and surface markers were analyzed by FACScan. After the antigen challenge, the numbers of CD8+ cells increased among the IEL, and the occurrence of both CD4+ and CD8+ cells increased among the LPL. The numbers of Thy-1+ cells and TCR- alpha/beta + cells increased among both the IEL and LPL, and LFA-1 expression was enhanced in both of these lymphocyte populations. The proliferative response of IEL and LPL to OVA increased in a dose-dependent manner after the antigen challenge in the OVA-sensitive mouse model. These results indicate that IEL and LPL, possibly those that have migrated from peripheral blood, are activated by orally administered antigens and cause mucosal damage in the food-sensitive enteropathy.

Animals↗
PubMed1996

Roles of gastric GATA DNA-binding proteins.

The gastric H+/K(+)-ATPase is a P-type ATPase that is specifically expressed in gastric parietal cells and is responsible for acid secretion into the stomach. We have found one or more gastric mucosal nuclear proteins that recognize a sequence motif in the 5'-upstream regions of the H+/K(+)-ATPase alpha- and beta-subunit genes. This gastric motif, (G/C)PuPu(G/C)NGAT(A/T)PuPy, may be a binding site for a positive transcriptional regulator that functions specifically in parietal cells. We further demonstrated using cDNA cloning and in situ hybridization that novel zinc-finger proteins (GATA-GT1 and GATA-GT2) are present in the gastric parietal cells and bind to this motif. The proteins activate the transcription of the reporter gene with the 5'-upstream region of the H+/K(+)-ATPase beta-subunit gene. These results suggest that gastric GATA DNA-binding proteins have important roles in transcriptional activation of H+/K(+)-ATPase genes in the parietal cells.

Amino Acid Sequence↗
PubMed1996

20-[18F]fluoroarachidonic acid: tissue biodistribution and incorporation into phospholipids.

The in vivo behavior of 20-[18F]fluoroarachidonic acid (18F-FAA) was investigated to evaluate its potential use as a radiotracer for studying the regional brain and heart lipid metabolism by positron emission tomography (PET). Tissue biodistribution studies in rats have revealed that 18F-FAA has a high uptake in the liver and lung, thus probably reflecting the metabolism, and is accompanied by both low in vivo defluorination and low blood levels. At 30 min postinjection, the uptake in the brain and heart reached values of 0.26 +/- 0.02 and 1.22 +/- 0.58% dose/g, respectively, with ratios to the blood radioactivity of 1.04 and 4.88, respectively. Lipid extraction at 30 min postinjection showed that 39% of the brain radioactivity was in the organic phase whereas the organic phase from heart tissue contained 73% of the total radioactivity. A TLC analysis demonstrated that 18F-FAA was mainly bound to phospholipids in the brain and heart tissue as expected. Based on the findings of this study, the utility of 18F-FAA as an in vivo tracer for cerebral phospholipid studies appears to be limited because of its relatively high radioactivity in the aqueous brain fraction. However, our findings do suggest that this agent might be useful as a tool for studies of cardiac phospholipid turnover, even though it demonstrated a poor heart-to-lung and heart-to-liver contrast.

Animals↗
PubMed1996

Amino acids and peptides. XXIX. Synthesis and antimetastatic effects of peptides and peptide-poly(ethylene glycol) hybrids related to the core sequence of the type III connecting segment domain of fibronectin.

Peptides (H-Glu-Ile-Leu-Asp-Val-NH2, H-Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr-NH2, H-Arg-Glu-Asp-Val-NH2) and their poly(ethylene glycol) (PEG) hybrids related to the core sequence of the type III connecting segment domain of fibronectin A chain were prepared by the solution method or the solid phase method. Their inhibitory effects on the adhesion and migration of B16-BL6 melanoma cells to fibronectin were assessed in vitro, and their therapeutic potency against tumor metastasis were also examined. Anti-adhesive and anti-migrative effects of the synthetic fibronectin-related peptids were superior to those of their PEG hybrids, so we found that the in vitro bioactivity of peptides decreased by PEGylation. In the in vivo assay, we found that the synthetic peptides containing Glu-Ile-Leu-Asp-Val and Arg-Glu-Asp-Val sequences exhibited an inhibitory effect on the experimental metastasis of B16-BL6 melanoma. Of the synthetic peptides, H-Glu-Ile-Leu-Asp-Val-NH2 exhibited the most potent inhibitory effect. Hybrid formation of Arg-Glu-Asp-Val with poly(ethylene glycol) resulted in potentiation of the inhibitory effect of the parent peptides. A mixture composed of PEG hybrids of Glu-Ile-Leu-Asp-Val, Arg-Glu-Asp-Val and Tyr-Ile-Gly-Ser-Arg dramatically inhibited tumor metastasis.

Animals↗
PubMed1996

Amino acids and peptides. XXVII. Solid phase synthesis of fibrinogen-related peptides with disulfide bond formed on solid support.

Fibrinogen-related peptides, monomeric cyclic peptides through a disulfide bond [cyclo(H-Cys-Arg-Gly-Asp-Phe-Cys-NH2), cyclo(H-Cys-Arg-Gly-Asp-Phe-Cys-Gly-NH2), cyclo(H-Cys-Arg-Gly-Asp-Cys-NH2) and cyclo(H-Cys-Arg-Gly-Asp-Cys-Gly-NH2)], were prepared by the solid phase method with disulfide bond formation on the solid support. The acetamidomethyl group was used for protection of the thiol group of Cys and synthetic peptide-resins were treated with iodine to give the disulfide bond. Monomeric cyclic peptides were obtained as main products. Purified S-acetamidomethylated peptides were also oxidized with iodine, but the desired materials could not be isolated by HPLC. The disulfide formation from S-acetamidomethylcysteine-containing peptide resin by iodine treatment on the solid support was more effective than that from S-acetamidomethylcysteine-containing peptide. The inhibitory effect of the cyclic peptides on platelet aggregation were much more potent than that of H-Arg-Gly-Asp-NH2.

Amino Acid Sequence↗
PubMed1996

[Genes for gastric proton pump and their transcriptional regulation].

The highly differentiated gastric parietal cell has a characteristic morphology and plays a specialized role in the hydrochloric acid secretion into the stomach lumen. The major enzyme in this system is an ATP-driven proton pump, the H+/K(+)-ATPase, which is responsible for proton translocation across the apical plasma membrane. The primary structures of the catalytic alpha and glycosylated beta subunits, and their transmembrane topology are similar to those of the corresponding subunits of Na+/K(+)-ATPase, suggesting that the reaction mechanism of both ATPases would be essentially the same if not identical. Most of the positions of introns in the H+/K(+)-ATPase subunit gene. These findings suggest that the alpha and beta subunit genes, respectively, of the two ATPases were derived from the common ancestors. We found that a DNA sequence motif, (G/C)PuPu(G/C)NGAT(A/T)PuPy, was located in the upstream regions of both alpha and beta subunit genes from human and rat. This motif may be a binding site for a positive transcriptional regulator that functions specifically in the parietal cells. cDNA cloning and in situ hybridization demonstrated that novel zinc finger proteins (GATA-GT1 and GATA-GT2) are present in the gastric parietal cells. These proteins bind to the (G/C)PuPu(G/C)NGAT(A/T)PuPy motif. Furthermore, they activate the transcription of the reporter gene with the 5'-upstream region of the alpha or beta subunit gene. These results suggest that gastric GATA DNA-binding proteins play important roles in transcriptional activation of H+/K(+)-ATPase genes in the parietal cells.

Amino Acid Sequence↗
PubMed1996

Tumor necrosis factor and interferon-gamma augment anticolon antibody- dependent cellular cytotoxicity in ulcerative colitis.

The effect of tumor necrosis factor (TNF) and interferon (IFN)-gamma on antibody-dependent cellular cytotoxicity (ADCC) in patients with ulcerative colitis (UC) was investigated. ADCC activity was measured by the 51Cr release assay, using peripheral blood mononuclear cells of healthy subjects as effector cells and RPMI 4788 cells derived from human colon cancer as target cells. ADCC activity under sera from healty subjects remained low whether or not the effector cells were pretreated with TNF (100 U/ml, 16h). Under sera from UC patients, ADCC activity of 13.9%, compared to 9.6% when pretreatment was deleted. The effect of IFN pretreatment (100 U/ml, 16h) was also examined under sera from UC patients; in that experiment activity rose to 26.8%, in comparison to a 10.7% when IFN-gamma pretreatment was deleted. Finally, when the effector cells were pretreated with both TNF and IFN-gamma (100 U/ml of each, 16h) the ADCC activity under sera from UC patients was higher than when either TNF or IFN-gamma were used alone. These results suggest that TNF and IFN-gamma, by increasing ADCC activity in UC lesions, are involved in cell injury in the colonic epithelium. IFN-gamma appears to increase ADCC activity by increasing the number of high affinity monocyte Fc gamma RI receptors, while TNF increases ADCC activity by a different mechanism.

Adjuvants, Immunologic↗
PubMed1996

Decrease of serum ascorbic acid concentrations in patients with diabetic macroangiopathy.

The relationship between serum ascorbic acid (AA) and diabetic macroangiopathy was studied. Fifty-six patients with noninsulin-dependent diabetes mellitus were examined, together with 20 healthy controls matched for age against the diabetes patients. Aortic pulse wave velocity (PWV) was taken as an index of the severity of atherosclerosis. The level of serum AA in diabetic patients was significantly lower than that of the controls. Among the diabetic groups, those with elevated PWV levels by age demonstrated a significant drop in AA. No significant differences were seen in the level of serum dehydroascorbic acid (DHAA) between patients and controls, nor were there any significant differences among patient groups. The concentration of serum AA was inversely related to the risk factors of atherosclerosis, such as body mass index, Apo B/ Apo A-I ratio, thiobarbituric acid-reactive substances (TBARS), and microalbumin in urine. It was inferred from these findings that the depletion of serum AA was apparent in diabetics with advanced atherosclerosis.

Adult↗
PubMed1996

Method for quantitative estimation of position perception using a joystick during linear movement.

We designed a method for quantitatively estimating self-motion perceptions during passive body movement on a sled. The subjects were instructed to tilt a joystick in proportion to perceived displacement from a giving starting position during linear movement with varying displacements of 4 m, 10 m and 16 m induced by constant acceleration of 0.02 g, 0.05 g and 0.08 g along the antero-posterior axis. With this method, we could monitor not only subjective position perceptions but also response latencies for the beginning (RLbgn) and end (RLend) of the linear movement. Perceived body position fitted Stevens' power law, where R=kSn (R is output of the joystick, k is a constant, S is the displacement from the linear movement and n is an exponent). RLbgn decreased as linear acceleration increased. We conclude that this method is useful in analyzing the features and sensitivities of self-motion perceptions during movement.

Acceleration↗
PubMed1996

[Changes in red blood cell aggregation rate after aneurysmal subarachnoid hemorrhage].

Red blood cell (RBC) aggregability is one of the important factors determining blood viscosity in the microcirculation. The RBC aggregation rate was monitored in 38 patients who underwent early aneurysmal clipping surgery after subarachnoid hemorrhage (SAH). The intravascular factors (hematocrit, serum albumin, alpha 2-macroglobulin, fibrinogen, IgG) that influence RBC aggregation were also examined. The RBC aggregation rate increased on days 5-7 but decreased significantly as a result of hypervolemic hemodilution therapy (H-H therapy). The hematocrit level was also reduced by H-H therapy. The serum albumin concentration decreased and the serum alpha 2-macroglobulin concentration increased significantly on days 5-7. After H-H therapy, the serum albumin concentration increased and the serum alpha 2-macroglobulin concentration decreased significantly. Serum IgG and plasma fibrinogen concentrations did not change significantly. It is known that albumin decreases and alpha 2-macroglobulin increases RBC aggregability. It has become apparent that serum albumin and alpha 2-macroglobulin play important roles in the determination of RBC aggregability after SAH. We conclude that the improvement in RBC aggregability induced by H-H therapy is effective for reversing progressive neurological deterioration due to cerebral vasospasm.

Adult↗
PubMed1996

[Color Doppler sonographic assessment of intrahepatic hemodynamics and shunt patency after transjugular intrahepatic portosystemic shunt (TIPS)].

The usefulness of color Doppler sonography for the assessment of intrahepatic hemodynamics and shunt patency was evaluated in a total of eight patients in whom the intrahepatic hemodynamics before and after transjugular intrahepatic portosystemic shunt (TIPS) could be serially examined by color Doppler sonography. In six of these patients the serial sonographic examinations could be followed for more than one year after TIPS creation. Within one month after TIPS creation, Vmax in the shunt was ranged from 87 cm/sec to 242 cm/sec (mean: 142.5 cm/ sec), and the flow direction in the right anterior portal vein was reversed in all patients. More than 70% stenosis of the shunt could be diagnosed by color Doppler sonography. When the shunt was confirmed by angiography to be more than 70% stenotic or occluded, Vmax in the shunt was decreased to less than 50 cm/sec and the blood flow in the right anterior portal vein become hepatopetal. From three months before stenosis or occlusion of the shunt, it was confirmed that Vmax in the shunt was less than 70 cm/sec or the blood flow of right anterior portal vein was hepatopetal. Color Doppler sonography was useful for the assessment of intrahepatic hemodynamics, and shunt patency and prediction of shunt stenosis or occlusion following TIPS creation.

Adult↗
PubMed1996

[Analysis of oxidative stress in rat fetus induced by clamping and reperfusion of uterine vessels].

Effects of oxidative stress (OS) on the fetus were studied under ischemic induced by clamping the uterine vessels of pregnant rats. OS was evaluated by superoxide (O-.2) released from red blood cells. Fetal RBC-O-.2 of the ischemic rats (clamping for 10 min and 20 min) was significantly higher than that of the control group (p < 0.01). Maternal RBC-O-.2 tended to increase, but not significantly. When readings before and after clamping were compared, the activity of fetal RBC SOD had increased in the ischemic group (clamping time for 10 min), but significantly decreased in the 20 min clamping rats (p < 0.01). Maternal SOD activity tended to decrease along with clamping time. The amount of lipidperoxide was significantly greater in the fetal ischemic liver subjected to clamping for 20 minutes than in the tissue subjected to clamping for 10 minutes. The lipidperoxide level was significantly higher in the fetal ischemic brain exposed for 10 minutes than in the control. These results indicate that fetal RBC-O-.2 increased along with ischemic time, and the maternal RBC-O-.2 had been influenced by the increase in fetal RBC-O-.2. Based on these observations, it was concluded that the OS due to ischemic injury had a more adverse effect on the fetal brain than on the liver.

Animals↗
PubMed1996

[Has the lifesaving technician system improved the outcome of out-of-hospital cardiopulmonary arrest patients?].

The role of the lifesaving technician (LST) system on the outcome of out-of-hospital cardiopulmonary arrest patients was examined retrospectively. The percentage of the patients resuming spontaneous circulation before arrival at the hospital was 2.2-4.3 times higher in the group with the prehospital care by LSTs ('93: 3.9% and '94: 2.0%) than by ordinary ambulance personnel (OAP) (0.9%), but there was no difference in the percentage of return of spontaneous circulation (LST '93: 33.0%, '94: 27.3%, OAP 37.8%), survival rate (LST '93: 3.1%, '94: 1.4%, OAP 1.8%) and discharge rate (LST '93: 1.0%, '94: 0.7%, OAP 1.8%) of the patients with cardiopulmonary arrest on arrival. Time interval from fire department receipt of call to ambulance departure and arrival at the hospital was significantly longer in the groups with the prehospital care by LSTs than by OAP. There was no difference in the outcome of cardiopulmonary arrest patients with the prehospital care by LSTs between '93 and '94. Our results suggest that making much more effort with more advanced technics to start the spontaneous circulation on the spot may be required to improve the outcome of out-of-hospital cardiopulmonary arrest patients.

Aged↗
PubMed1996

[Balloon angioplasty and metallic stent].

Recently, interventional radiology (IVR) has been playing an important role as a treatment for the arterial occlusive diseases. Balloon angioplasty (PTA) is widely used for the stenotic lesions and clinical results are acceptable. However, some other procedures are frequently needed, and metallic stents (MS) are useful quite often. There are three main groups of stents: self-expanding stainless metallic stents (Z-stent, Wallstent), balloon-expandable stents (Palmaz stent, Strecker stent), and shape memory alloy stents, which are not clinically available for the iliac and femoro-popliteal arteries now in Japan except for Palmaz stent. However, it is expected that these MS will be available soon. In this paper we described the clinical utility of PTA and MS for the arterial occlusive diseases in the iliac and femoro-popliteal lesions based on our experience and past reports and also mentioned the future of IVR.

Angioplasty, Balloon↗
PubMed1996

[An operative case of bilateral partial anomalous pulmonary venous return using a direct anastomosis between the right atrial appendage and the superior vena cava].

We have experienced a case of bilateral partial anomalous pulmonary venous return without atrial septal defect. Right upper pulmonary vein returned to the superior vena cava and left upper pulmonary vein returned to the left brachiocephalic vein. This type of bilateral partial anomalous pulmonary venous return was extremely rare, and only 4 such cases have been reported in the Japanese literature. The patient, aged 3 years and 11 months, was successfully operated on, using a direct anastomosis between the right atrial appendage and the superior vena cava. This procedure is considered to be advantageous because both this right atriotomy line and suture line avoid injury of the sinus node and the sinuatrial node artery and no foreign material is used. A decrease in postoperative arrhythmia can also be expected from this procedure.

Anastomosis, Surgical↗