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Biomedical subjects

Y Yoshimura

Publications and source records attributed to Y Yoshimura.

At least 253 records · Page 14Linked to original sources
PubMed1995

A rapid and non-invasive selection of transgenic embryos before implantation using green fluorescent protein (GFP).

Non-invasive selection of transgenic mice was performed at the stage of preimplantation embryos. The morulae collected from wild female mated with hemizygous transgenic male expressing Aequorea victoria green fluorescent protein (GFP) under chicken beta-actin promoter could be classified as green or non-green under a fluorescent microscope. All the green embryos were shown to carry the transgene by PCR analysis. Taking advantage of the detection of GFP expression can be done non-invasively, the selected embryos were demonstrated to be able to developed to term with 100% of accuracy of the selection.

Animals↗
PubMed1995

Enantioselective determination of pazinaclone, a new isoindoline anxiolytic, and its active metabolite in rat plasma by high-performance liquid chromatography.

A sensitive and specific high-performance liquid chromatographic method has been developed for the simultaneous determination of the enantiomers of pazinaclone (DN-2327), a new anxiolytic agent, and those of its active metabolite, M-II, in rat plasma. Organic solvent extraction of pazinaclone, M-II, and internal standard (I.S.) in plasma was followed by separation of the analytes from other metabolites using an achiral reversed-phase column. Fluorescence detection was employed with excitation and emission wavelengths of 328 and 367 nm, respectively. Separation of all the enantiomers and I.S. was then accomplished with normal- and chiral-phase columns connected in series. For each analyte, the lower quantitation limit was 0.5 ng/ml. The assay has been applied to a chiral inversion study in rats. Chiral conversion from one enantiomer of pazinaclone to the other hardly occurred. This method is suitable for enantioselective pharmacokinetic and toxicokinetic studies in animals.

Animals↗
PubMed1995

Enantioselective pharmacokinetics in animals of pazinaclone, a new isoindoline anxiolytic, and its active metabolite.

The enantioselective pharmacokinetics of a new anxiolytic, pazinaclone (DN-2327), and its active metabolite, M-II, were studied in animals. In rats and dogs given racemic pazinaclone intravenously, the total clearance and volume of distribution of (S)-pazinaclone were lower than those of (R)-pazinaclone, whereas the opposite results were obtained in monkeys. The differences in disposition were consistent with enantioselective protein binding, where the unbound fraction was greater for (R)-pazinaclone than that for the (S)-enantiomer in rats and dogs; the reverse was noted in monkeys. Lower clearance and distribution for (S)-pazinaclone in rats and dogs, and for the (R)-enantiomer in monkeys, resulted in comparable plasma profiles for the pazinaclone enantiomers and thereby those of the corresponding enantiomers of M-II. The unbound clearance (CLu) of (S)-pazinaclone was, however, greater than that of the antipode in rats and dogs and the CLu of each enantiomer was similar in monkeys. Thus, enantioselectivity in the kinetics of (S)- and (R)-pazinaclone appears to reside largely in plasma binding differences and is unrelated to variations in intrinsic clearance. The first-pass metabolism of (S)- and (R)-pazinaclone on oral administration of the racemate was enantioselective, with respective bioavailabilities of 1.7 and 0.8% in rats, 10.4 and 1.9% in dogs, and 0 and 11.4% in monkeys. Therefore, the enantioselectivity was more pronounced after oral dosing.

Absorption↗
PubMed1995

Changes in localization of ovarian immunoreactive estrogen receptor during follicular development in hens.

The aim of this study was to examine the changes of ovarian estrogen receptor (ER) localization in hens to determine the significance of estrogen-ER interactions for the regulation of follicular functions during their development. The ER was localized by immunocytochemistry in the various developmental and regressing stages of follicles, namely cortical and white follicles, the largest (F1, matured follicle) and third largest preovulatory follicles (F3, rapid growth phase follicle), and post-ovulatory follicles (POF). No immunoreaction for ER was observed in the cortical follicles, whereas the interstitial cells in the outer theca externa were ER positive in white follicles. The islets of epithelial cells (identical to estrogen producing cells) in the outer theca externa and granulosa cells were ER positive in F3 follicles. These ER immunoreactions observed in F3 follicle were remarkably reduced in F1 and POF. These results suggest that estrogen-ER interactions may be responsible for the follicular growth, and the loss of ER may be involved in the mechanism of follicular maturation. The estrogen-ER interactions may be also involved in the local control of the steroid production in follicles.

Animals↗
PubMed1995

Bridging annuloplasty for common atrioventricular valve regurgitation.

Progressive common atrioventricular valve regurgitation is a serious condition in children with a univentricular heart. We developed a repair procedure that consists of using a Teflon tape bridge and total circular annuloplasty to divide the common atrioventricular valve into two atrioventricular valves. This procedure was performed in 2 infants, and the results were satisfactory. Details of the technique are described.

Child, Preschool↗
PubMed1995

Phosphotyrosyl protein phosphatase-like activity of a clonal osteoblastic cell line (MC3T3-E1 cell).

The homogenate of MC3T3-E1 cells hydrolysed phosphotyrosine, but not phosphoserine or phosphothreonine at acidic pH. It dephosphorylated lysozyme and Raytide (a gastrin analogue peptide) phosphorylated by tyrosine kinase, but showed little activity toward histones phosphorylated by cyclic AMP-dependent protein kinase. Dephosphorylation of phosphorylated lysozyme and Raytide were inhibited by zinc and vanadate, but were insensitive to okadaic acid. These data suggest that the osteoblastic cell line MC3T3-E1 has a phosphotyrosyl protein phosphatase-like activity that may participate in cellular regulation involving protein tyrosine phosphorylation.

3T3 Cells↗
PubMed1995

Full-thickness skin grafting of postsurgical oral defects: short- and long-term outcomes.

PURPOSE: This study evaluated the use of full-thickness skin grafts (FTSGs) following excision of precancerous and cancerous oral lesions. MATERIALS AND METHODS: Fourteen oral lesions, including five leukoplakias, one carcinoma in situ, two verrucous carcinomas, and six squamous cell carcinomas with varying grade of keratinization and invasion were skin grafted after excision. The size of the graft ranged from 16 x 22 mm to 40 x 50 mm, and the fixation period was 8 to 13 days. The grafts were evaluated for necrosis as a short-term result and shrinkage and recurrence of the lesion as long-term results. RESULTS: Three cases with more than moderate necrosis of the grafted skin were observed (21.4%). Shrinkage was observed in 23% of the 14 skin grafts and tumor recurrence was observed in three FTSGs (2 patients). CONCLUSIONS: The results suggest that the paucity of the blood supply in the grafted bed, and the uneven pressure and immobilization of the grafted skin, influence the success of the procedure, and that proper case selection is necessary.

Aged↗
PubMed1995

A comparison of three methods used for treatment of ranula.

PURPOSE: This report compares the treatment results for oral and plunging ranulas. PATIENTS AND METHODS: Twenty-seven patients were retrospectively examined concerning treatment methods and recurrence on the basis of their medical records. The surgical specimens were also examined microscopically. RESULTS: Four patients had excision of the ranula only, 22 had marsupialization, and nine had removal of the sublingual gland combined with the excision of the ranula. These treatments showed a 25.0%, 36.4% and 0% recurrence rate, respectively. Histological observation revealed no epithelial lining in any of the examined specimens. CONCLUSIONS: Removal of the sublingual gland combined with the ranula was the most reliable method among the above three used.

Humans↗
PubMed1995

Administration of human chorionic gonadotropin for in vitro fertilization-embryo transfer based on the serum luteinizing hormone (LH) concentration: the importance of synchronization with endogenous LH rises.

OBJECTIVE: To examine whether synchronized administration of hCG at the onset of the endogenous LH rise promotes successful IVF. DESIGN: A prospective randomized study. SETTING: In vitro fertilization program at a university hospital. PATIENTS: A total of 208 IVF cycles in 148 patients. INTERVENTIONS: Serum LH concentrations were measured daily and hMG was administered daily. Independent of follicle size and E2 concentration, hCG was administered as soon as the LH concentration exceeded the J level, defined as the minimum value + (the day 3 value-the minimum value) x 1/3(J group). Alternatively, hCG was administered when the serum LH concentration turned to increase but was still less than the J level, or 1 day after the serum LH concentration exceeded the J level (non-J group). RESULTS: The rates of total and ongoing pregnancy per cycle were significantly higher in the J group (35.6% and 26.0%, respectively, n = 104) than in the non-J group (21.2% and 12.5%, respectively, n = 104). Pregnancies in the J group were achieved over a wide range of dominant follicle diameters (13 to 25 mm), E2 levels (198 to 1,700 pg/mL; conversion factor to SI units, 3.671), and E2 level per follicle > or = 12 mm (24 to 225 pg/mL per follicle) recorded on the day of hCG administration. CONCLUSION: Synchronized administration of hCG in accordance with endogenous LH rises produces a high rate of pregnancy in IVF.

Adult↗
PubMed1995

Use of the palatal mucosal graft for reconstruction of the eye socket.

Hard palate mucosa is thick and rigid. Grafted with its periosteal layer, it can be a supportive material. Simultaneously, wound healing of the palatal donor site is very rapid and the patient does not experience any pain. Such characteristics of the palatal mucosal graft have led to its use in reconstruction of the eyelids, including the tarsal plate. Nevertheless, there have been very few reports on its use in this are of the face. Herein we report the use of the palatal mucosal graft in reconstruction of the eye sockets.

Adult↗
PubMed1995

Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphate composite (Ceratite) as a bone substitute.

The craniofacial approach to cranial base tumors has widened the operability of tumors with intracranial invasion. However, the resulting skull base defect must be reconstructed adequately to prevent postoperative morbidity and mortality. We use hydroxyapatite-tricalciumphosphate ceramic (Ceratite) as a bone substitute material to reconstruct the skull base defect in combination with the pericranial flap, ensuring separation between the sinonasal cavity and epidural cavity. Although the nasal surface of the Ceratite block is left exposed directly to the sinonasal cavity, it was shown to be epithelialized within 6 months postoperatively. Our method is less invasive than any other conventional method and may offer more chance of curative resection of tumors with anterior skull base invasion.

Adenocarcinoma↗
PubMed1995

Integrated life-sized solid model of bone and soft tissue: application for cleft lip and palate infants.

The recent development of three-dimensional computed tomography (3D-CT) and laser stereolithography has allowed the creation of life-sized skeletal models. The development of helical CT has enabled us to apply this method to very young children. However, skeletal models alone do not reveal the spatial relationship between soft tissue and bone in complicated craniofacial deformities. We have therefore developed a model that shows both soft and bony tissue by first using CT values that result in a model in which soft tissue is solid and bone is replaced by empty space. The space is then filled with plaster to represent the skeleton. This model also can provide baseline data for evaluating facial growth after surgical repair of clefts. Two infants with cleft lip and palate are presented to illustrate this method of creating an integrated solid model and its applications.

Bone and Bones↗
PubMed1995

Comparison of the selectivity of anti-varicella-zoster virus nucleoside analogues.

We compared the selectivity of six anti-varicella-zoster virus (VZV) drugs, which are clinically available or of which clinical efficacy for the treatment of VZV infections has been reported. Sorivudine (BV-araU) had the most potent anti-VZV effect in the plaque inhibition assay, followed by brivudine (BVDU) and 5-propynyl-arabinofuranosyluracil (Pry-araU). All test compounds, except vidarabine (AraA), had only a very weak effect on human embryonic lung cell growth. The selectivity indexes (ID50 for cell growth/ED50 for VZV plaque inhibition) of BV-araU, BVDU, and Pry-araU were > 1,000,000, 20,000, and > 10,000, respectively, while those of acyclovir and penciclovir ranged from 600 to 800. AraA was much less selective than any of the other drugs tested. We measured the amount of [3H] thymidine incorporated into the acid-insoluble fraction of VZV-infected cells to determine the ability of these drugs to selectively inhibit viral DNA synthesis. [3H]Thymidine incorporation was markedly inhibited by all anti-VZV compounds, except BVDU. Treatment of infected cells with drugs from 32 to 38 hr after infection inhibited the DNA synthesis to the same extent as VZV plaque formation, except that AraA inhibited the DNA synthesis at a lower dose than for VZV plaque formation. DNA synthesis in non-infected growing cells was inhibited to the same extent as cell growth. A particularly high selectivity index for the inhibition of DNA synthesis was noted for BV-araU, which was defined as the ratio of inhibitions of DNA synthesis in VZV-infected and non-infected. The highest selectivity indexes were recorded for BV-araU > Pry-araU > acyclovir > or = penciclovir > AraA.

Antiviral Agents↗
PubMed1995

Effects of beta-1 integrins in the process of implantation.

The expression and function of beta 1 integrins on human decidual cells were investigated. Flow cytometric analysis revealed that the cultured decidual cells expressed a high level of the beta 1 subunit on the cell surface. Mouse blastocysts attached to and spread onto cultured human decidual cells. Attachment of the blastocysts was a necessary prerequisite for the further outgrowth of trophoblasts. The addition of a monoclonal antibody recognizing the beta 1 subunit to the cultured decidual cells did not affect the rates of hatching and attachment of blastocysts. The outgrowth of embryos on decidual cells was inhibited by the addition of the anti-beta 1-subunit antibody in a dose-dependent manner. Furthermore, exposure of decidual cells to the anti-beta 1-subunit antibody significantly inhibited the extent of outgrowth of trophoblasts, implying that blastocyst attachment and outgrowth is mediated by different mechanisms. These observations suggest that beta 1 integrins on decidual cells may be involved in the process of blastocyst development and differentiation after attachment.

Antibodies, Monoclonal↗