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Biomedical subjects

M Sakaguchi

Publications and source records attributed to M Sakaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2003

[Apico-aortic conduit for severe aortic stenosis in elderly].

We described a case of an 84-year-old woman with end stage aortic stenosis in whom favorable results were obtained after constructing apico-aortic conduit bypass. The patient admitted due to complete atrio ventricular(AV) block and respiratory insufficiency. Although a permanent pacemaker was implanted, heart failure did not improve. Echocardiograms showed small aortic annulus and severe calcific aortic stenosis with a measured trans valve gradient of 100 mmHg. Since cardiac failure deteriorated and she lapsed into hypotension and acute renal failure, an emergency operation was performed. The left lateral thoracotomy was performed with cardiopulmonary bypass. A bioprosthetic valved conduit was anastmosed to the left ventricle apex. Another graft was anastomosed to the discending thoracic aorta. The operation was completed by anastomosing the tailored ends of the grafts together. Although the patient required hemodialysis for 2 weeks after operation, she was discharged on 57th day after operation without any complications. Apico-aortic conduit is considered to be an useful procedure for elderly patients who were not good candidates for conventional valve replacement.

Aged↗
PubMed2002

Embryonic and calving losses in bovine mixed-breed twins induced by transfer of in vitro-produced embryos to bred recipients.

One or two in vitro-produced (IVP) Japanese Black (JB) cattle embryos at 8 days after in vitro fertilization were transferred to the contralateral uterine horn of previously bred Japanese Shorthorn (JSH) or JSH-JB cross recipients, and then the occurrence of early embryonic death, abortion during mid- and late gestation, and calving loss were recorded. The survival rate of embryos, including indigenous ones, was not affected by the number of embryos transferred, and a significantly higher twinning rate (68% of pregnant recipients at 80 days after transfer) was achieved when two IVP embryos were transferred, as compared with the rate when one IVP embryo was transferred (24%). In late ET (recipients at 8.5-9.0 days after the onset of oestrus), the embryo survival rate (22%) and the pregnancy rate (42%) at 80 days after ET were significantly lower than those rates in the synchronous ET (recipients at 8.0 days after the onset of oestrus; 47 and 79%, respectively). In the early ET (recipients at 6.0-7.5 days after the onset of oestrus), no significant differences from the synchronous ET were detected in these rates. Twenty-six percent of twin pregnant recipients were aborted during mid- or late-pregnancy, and 39% of twin calves were stillborn. The mean gestation length of the twin-bearing JSH dams (276 days) was 1 week shorter than that of the single-bearing JSH dams, and it was 2 weeks shorter than that of the JB dams bearing a single JB calf derived from the IVP embryos. The longer gestation length of single JB calves derived from IVP embryos resulted in a significantly higher mean birth weight than that of in vivo control calves with the standard length of gestation. In conclusion, the number of embryos to be transferred did not affect the embryo survival rate, and the transfer of two IVP embryos to previously inseminated recipients induced a significantly higher twinning rate during early pregnancy than that of one IVP embryo transfer. The incidence of embryonic losses during early pregnancy increased when Day 8 embryos were transferred to the recipients later in the oestrous cycle (>8.0 days). The results suggested that one cause of the high rate of abortions and stillbirths in twin-bearing dams is the difference in the mean gestation length between the native JSH and JB foetuses derived from transferred IVP embryos.

Abortion, Spontaneous↗
PubMed2002

Analysis of HLA in children with gelatin allergy.

Systemic immediate reactions including anaphylaxis to gelatin in vaccines have been reported. However, the number of such reports is very small compared with the number of children exposed to gelatin. The present study was designed to investigate whether susceptibility or resistance to gelatin allergy is associated with human leukocyte antigen (HLA) class II gene. Blood samples were obtained from 49 patients with gelatin allergy and specific IgE to gelatin. DNA-based HLA class II typing was performed to determine the DRB1, DQB1 and DPB1 alleles. Genotype frequencies were compared with those found in 240 unrelated controls. The frequency of DQB1*0303 (55.1%) was significantly higher in the patients than in the control subjects (32.1%). The frequency of DPB1*0402 was also significantly higher in the patients (32.7%) than in the control subjects (15.4%). On the other hand, the frequency of subjects carrying DRB1*15 (DRB1*1501 and DRB1*1502) was significantly lower among the patients group (18.4%) than among the controls (40.8%). We found that DQB1*0303 and DPB1*0402 were positively associated with the IgE response for gelatin, while DRB1*15 was negatively associated with it.

Child↗
PubMed2002

Possible mechanism for acceleration of meiotic progression of bovine follicular oocytes by growth factors in vitro.

The mechanism for the accelerating effects of epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) on the meiotic cell cycle of bovine oocytes cultured in vitro was investigated. Cumulus-oocyte complexes (COCs) were obtained from small (< or = 3 mm in diameter), medium (4-6 mm in diameter) or large (7-10 mm in diameter) ovarian follicles and cultured with or without a combination of EGF and IGF-I (growth factors). Growth factors significantly increased the frequency of first polar body extrusion of oocytes derived from small follicles at 16 h of culture (PB16 oocytes; with growth factors: 75%; without growth factors: 55%), but did not increase the frequency in oocytes from medium or large follicles. COCs from small follicles were cultured with individual growth factors and sampled for kinase activity. The frequencies of polar body extrusion in EGF only (67%) and EGF + IGF-I (75%) treatment groups were significantly higher than those in the control (no growth factor) group (49%), but not significantly higher than in the IGF-I only group (63%). The H1 kinase activity at 6-8 h of culture in each group increased significantly from the baseline value at 0 h of culture, and the H1 kinase activities in the EGF only, IGF-I only and EGF + IGF-I treatment groups were significantly higher than those in the control group at 8 h of culture. MAP kinase activity was significantly higher than the baseline value and significantly higher than that in the control group at 6 h of culture in the EGF treatment group only. In conclusion, EGF and IGF-I act on COCs from small follicles to accelerate the meiotic cell cycle of the oocytes. This accelerating effect may be related to increased H1 and MAP kinase activities during the early stages of maturation.

Animals↗
PubMed2002

[Graft holding system; a new device for coronary artery bypass grafting].

A new graft holding system for coronary artery bypass grafting was described. This system was an application of a memo-clip, which was composed of a flexible arm and 2 paper clips at both ends. A graft was wrapped by a piece of sponge and pinched indirectly by one of the clips. The other clip was fixed at an edge of the sternal retractor. Regardless of the size of the graft or the amount of the surrounding tissue, the graft can be fixed securely at one's pleased position due to a flexible arm of the device. Intimal injury can be avoided referring to the gentle holding of a piece of sponge. It enables us to place precise stitches and to minimize handling, anastomosis time, and leakage.

Anastomosis, Surgical↗
PubMed2001

Antiproliferative activity of REIC/Dkk-3 and its significant down-regulation in non-small-cell lung carcinomas.

We recently reported the cloning of the REIC/Dkk-3 gene, whose expression was shown to be down-regulated in many human immortalized and tumor-derived cell lines [T. Tsuji et al. (2000) Biochem. Biophys. Res. Commun. 268, 20-24]. In the present study, we demonstrated that expression of the exogenous REIC/Dkk-3 gene in tumor cells inhibited cell growth. Furthermore, the level of REIC/Dkk-3 mRNA in normal human cells was lowest in the late G(1) phase during the cell cycle. Then we found that the expression of REIC/Dkk-3 was significantly down-regulated in surgically resected non-small-cell lung carcinomas. We determined the REIC/Dkk-3 locus on chromosome 11p15, where loss of heterozygosity has frequently been observed in human tumors. These findings indicate that REIC/Dkk-3 may function as a tumor suppressor.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Lack of contact transmission of recombinant Marek's disease virus type 1 expressing the fusion protein of Newcastle disease virus.

To clarify the level of excretion of a recombinant Marek's disease virus type 1 (rMDV1) that confers good protection in chickens against both Marek's and Newcastle diseases, even in the presence of maternal antibodies, contact transmission tests were conducted. Naïve chickens kept in the same cage or room with chickens inoculated with rMDV1 did not produce antibodies against MDV1 or the fusion protein of Newcastle disease virus. Moreover, the rMDV1 was not isolated from the dander of chickens inoculated with rMDV1. Even under the stressful conditions of forced molting and a high temperature environment, rMDV1 was not isolated from the dander of inoculated birds. The viral DNA, however, was detected from the dander of chickens inoculated with rMDV1 as well as a commercial vaccine. These findings indicate that dander from chickens inoculated with rMDV1 includes viral DNA, but does not contain infectious virus.

Animals↗
PubMed2001

Amino acid residues before the hydrophobic region which are critical for membrane translocation of the N-terminal domain of synaptotagmin II.

We examined the fine structure of the type I signal-anchor sequence of synaptotagmin II, which has a 60-residue N-terminal domain followed by a hydrophobic region (H-region), focusing on the hinge region between the N-terminal and the H-regions. It was found that the charged or highly polar residues support the translocation of the N-terminal domain through the endoplasmic reticulum membrane at specific positions in the hinge. The residue requirement correlated with the turn propensity scale for transmembranes. It is suggested that a certain conformation, likely helical hairpin, in the hinge is critical for N-terminal domain translocation.

Amino Acid Sequence↗
PubMed2001

NHE6 protein possesses a signal peptide destined for endoplasmic reticulum membrane and localizes in secretory organelles of the cell.

The NHE6 protein is a unique Na(+)/H(+) exchanger isoform believed to localize in mitochondria. It possesses a hydrophilic N-terminal portion that is rich in positively charged residues and many hydrophobic segments. In the present study, signal sequences in the NHE6 molecule were examined for organelle localization and membrane topogenesis. When the full-length protein was expressed in COS7 cells, it localized in the endoplasmic reticulum and on the cell surface. Furthermore, the protein was fully N-glycosylated. When green fluorescent protein was fused after the second (H2) or third (H3) hydrophobic segment, the fusion proteins were targeted to the endoplasmic reticulum (ER) membrane. The localization pattern was the same as that of fusion proteins in which green fluorescent protein was fused after H2 of NHE1. In an in vitro system, H1 behaved as a signal peptide that directs the translocation of the following polypeptide chain and is then processed off. The next hydrophobic segment (H2) halted translocation and eventually became a transmembrane segment. The N-terminal hydrophobic segment (H1) of NHE1 also behaved as a signal peptide. Cell fractionation studies using antibodies against the 15 C-terminal residues indicated that NHE6 protein localized in the microsomal membranes of rat liver cells. All of the NHE6 molecules in liver tissue possess an endoglycosidase H-resistant sugar chain. These findings indicate that NHE6 protein is targeted to the ER membrane via the N-terminal signal peptide and is sorted to organelle membranes derived from the ER membrane.

Amino Acid Sequence↗
PubMed2001

Significance of chymase-dependent angiotensin II-forming pathway in the development of vascular proliferation.

BACKGROUND: Vascular tissues of humans and dogs contain chymase as an angiotensin II-forming enzyme. In this study, we investigated whether chymase-dependent angiotensin II formation plays a crucial role in the development of vascular proliferation in dog grafted veins. METHODS AND RESULTS: The right external jugular vein of dogs was grafted to the ipsilateral carotid artery. As a control group, the right external jugular veins in dogs that had not received grafts were used. In the chymase inhibitor-treated group, the vein was infiltrated with 10 micromol/L Suc-Val-Pro-Phe(P)(OPh)(2) and was grafted to the carotid artery. In the placebo-treated group, ACE activity in the grafted veins was significantly lower than that in the control veins up to 7 days after the operation, whereas chymase activity was increased significantly. After 7 days, the mRNA levels of collagen I, collagen III, and fibronectin, all of which are induced by an increase of angiotensin II action, were significantly increased in the grafted veins, and the intima-media ratio of the grafted veins was also increased. In the chymase inhibitor-treated group, the chymase activity in the grafted veins 7 days after the operation was suppressed to 12.1%. The elevated mRNA levels of fibronectin, collagen I, and collagen III in the grafted veins were significantly suppressed by treatment with the chymase inhibitor, and the intima-media ratio was also decreased significantly. CONCLUSIONS: We demonstrate for the first time that chymase-dependent angiotensin II formation plays an important role in the development of vascular proliferation in the grafted veins.

Angiotensin II↗
PubMed2001

Oral administration of a specific chymase inhibitor, NK3201, inhibits vascular proliferation in grafted vein.

Chymase may play an important role in vascular proliferation, as shown by in-vitro experiments, but the role of chymase in vivo has been unclear. In this study, we investigated the effect of a novel chymase inhibitor, NK3201, on this proliferation in dog grafted veins. NK3201 inhibited human and dog chymases, but not rabbit ACE. NK3201 suppressed the Ang I-induced vascular contraction in isolated dog arteries in the presence of an ACE inhibitor, and the IC50 value of chymostatin and NK3201 in dog artery was 320 nM. In dog, the concentration of NK3201 in blood was about 10 microM at 24 h after oral administration of the drug (5 mg/kg). In the group treated with NK3201, each dog was administered orally 5 mg/kg per day from 5 days before to the day before the removal of the grafted veins. Each dog underwent right common carotid artery bypass grafting with the ipsilaterial external jugular vein. By 28 days after grafting, a significant vascular proliferation was observed in the grafted veins and the chymase activity was also increased significantly. Treatment with chymase inhibitor significantly suppressed the proliferation of the grafted veins and the increased chymase activity. In this study, we demonstrate for the first time that oral administration of a specific chymase inhibitor, NK3201, appears useful for preventing vascular proliferation.

Acetamides↗
PubMed2001

C-reactive protein is an independent predictor of the rate of increase in early carotid atherosclerosis.

BACKGROUND: An elevated plasma concentration of high-sensitivity C-reactive protein (hs-CRP) is a strong predictor of cardiovascular events. However, there have been no longitudinal studies of the relations between development of atherosclerotic lesions and hs-CRP concentrations. Furthermore, it remains unknown whether increased hs-CRP concentrations result in the development of atherosclerosis. METHODS AND RESULTS: The study included 179 outpatients 40 to 79 years of age who were treated at our institute for traditional risk factors for cardiovascular disease. The patients had no evidence of advanced carotid atherosclerosis at the time of baseline examination. Patients underwent repeated ultrasonographic evaluation of the carotid arteries for 35+/-10 months. Blood samples were collected for hs-CRP measurements. Based on focal intima-media thickening >/=1.1 mm representing plaque, plaque number (PN) and plaque score (PS; the sum of all plaque thicknesses) were calculated. The development of atherosclerosis was estimated by the formula Deltavalue/year=(last value-baseline value)/number of follow-up years. Multivariate linear regression analysis revealed that the log-transformed value for hs-CRP concentration was not related to baseline PN or PS but was related to DeltaPN/year and DeltaPS/year (beta=0.29 and 0.30; P<0.001 for both) independently of the effect of traditional risk factors. CONCLUSIONS: During the early stages of carotid atherosclerosis, the hs-CRP concentration is a marker of carotid atherosclerotic activity rather than extent of atherosclerosis.

Adult↗
PubMed2001

Inhibitory mechanism of daphnodorins for human chymase.

We investigated the inhibitory mechanisms of daphnodorins for human chymase using three-dimensional molecular modeling. In daphnodorin A-human chymase complex, daphnodorin A was fixed to the active site via hydrogen bonds with Ala177, Phe29, and Gly199 in human chymase, and it formed hydrogen bonds with Ser182 and Gly180, and this complex was formed stably. In daphnodorin B-human chymase complex, daphnodorin B formed hydrogen bonds with Lys28 and Phe29 in human chymase, but it could not form hydrogen bonds with Gly199, Ala177, and Lys179. The phenyl group of daphnodorin B shifted from the P1 hole in human chymase in comparison with that of daphnodorin A. For the inhibition of human chymase by daphnodorins, we indicated that it was significant whether daphnodorins formed hydrogen bonds with Ala177 located in the P1 hole, Ser182 located in the active site, Gly180 located in the anion hole, and with Gly199, Phe29, and Lys28 in human chymase.

Benzopyrans↗
PubMed2001

Evidence in support of a four transmembrane-pore-transmembrane topology model for the Arabidopsis thaliana Na+/K+ translocating AtHKT1 protein, a member of the superfamily of K+ transporters.

The Arabidopsis thaliana AtHKT1 protein, a Na(+)/K(+) transporter, is capable of mediating inward Na(+) currents in Xenopus laevis oocytes and K(+) uptake in Escherichia coli. HKT1 proteins are members of a superfamily of K(+) transporters. These proteins have been proposed to contain eight transmembrane segments and four pore-forming regions arranged in a mode similar to that of a K(+) channel tetramer. However, computer analysis of the AtHKT1 sequence identified eleven potential transmembrane segments. We have investigated the membrane topology of AtHKT1 with three different techniques. First, a gene fusion alkaline phosphatase study in E. coli clearly defined the topology of the N-terminal and middle region of AtHKT1, but the model for membrane folding of the C-terminal region had to be refined. Second, with a reticulocyte-lysate supplemented with dog-pancreas microsomes, we demonstrated that N-glycosylation occurs at position 429 of AtHKT1. An engineered unglycosylated protein variant, N429Q, mediated Na(+) currents in X. laevis oocytes with the same characteristics as the wild-type protein, indicating that N-glycosylation is not essential for the functional expression and membrane targeting of AtHKT1. Five potential glycosylation sites were introduced into the N429Q. Their pattern of glycosylation supported the model based on the E. coli-alkaline phosphatase data. Third, immunocytochemical experiments with FLAG-tagged AtHKT1 in HEK293 cells revealed that the N and C termini of AtHKT1, and the regions containing residues 135-142 and 377-384, face the cytosol, whereas the region of residues 55-62 is exposed to the outside. Taken together, our results show that AtHKT1 contains eight transmembrane-spanning segments.

Alkaline Phosphatase↗
PubMed2001

Structure of a full-length cDNA clone for the pro-alpha1(V/XI) collagen chain of red seabream.

The cDNA of type V/XI collagen alpha1 (rsCOL) chain has been isolated from cells established from eyed-period eggs of red seabream, Pagrus major, and sequenced. The amino acid sequence deduced from red seabream alpha1(V/XI) chain resembles that of type XI collagen alpha1 chain. On the other hand, tissue distribution of rsCOL resembles that of type V collagen based on RT-PCR analysis. This is the first report of the cloning of the full-length cDNA of type V/XI collagen alpha1 chain from fish.

Amino Acid Sequence↗
PubMed2001

Cilostazol suppresses intimal formation in dog grafted veins with reduction of angiotensin II-forming enzymes.

Cilostazol prevents neointimal formation, but its mechanism has remained unclear. We investigated whether intimal formation in dog grafted veins is suppressed by cilostazol, and studied the effect of cilostazol on angiotensin II-forming enzymes. The external jugular vein was grafted to the carotid artery, and cilostazol (60 mg/kg/day) was administered orally. By 28 days after the surgery, the intimal cross-sectional area of the grafted vein was reduced to 16.7% by treatment of cilostazol, and the activities of angiotensin II-forming enzymes were suppressed significantly. The inhibitory effect of cilostazol in intimal formation may be dependent on inhibition of angiotensin II-forming enzymes.

Angiotensin II↗
PubMed2001

Analysis of the canine IgE-binding epitope on the major allergen (Cry j 1) of Japanese cedar pollen with anti-Cry j 1 monoclonal antibodies.

In our previous study [Immunology 91 (1997) 161] using monoclonal antibodies (mAbs) specific to Cry j 1, a major allergen in Japanese cedar (Cryptomeria japonica) pollen, we identified five independent epitopes (EP-1-EP-5) on the molecule and found that EP-1 and EP-5 are the predominant allergic epitopes for humans and monkeys, respectively. In this study, we analyzed the epitopes recognized by IgE in the sera of 10 dogs sensitive to C. japonica pollen allergen using an IgE-ELISA inhibition method with these mAbs. The IgE reaction patterns varied among dogs. In eight of the 10 dogs, IgE recognized EP-5 which is a predominant allergic epitope for monkeys with the pollenosis. In four dogs, IgE recognized EP-1 which is a predominant allergic epitope for human patients with the pollenosis. In three dogs, IgE recognized EP-4 which is a heat-stable epitope. EP-5 is a predominant allergic epitope for dogs and some, but not all, dogs have IgE reaction patterns to the epitopes similar to those of humans.

Allergens↗