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Biomedical subjects

Y Yoshimura

Publications and source records attributed to Y Yoshimura.

At least 199 records · Page 11Linked to original sources
PubMed1997

A facile, alternative synthesis of 4'-thioarabinonucleosides and their biological activities.

4'-Thioarabinonucleosides, which are potential antiviral agents, were synthesized from D-glucose. 1,4-Anhydro-4-thioarabitol (8), which can be derived from diacetone glucose in nine steps, was subjected to Pummerer rearrangement after protection of the hydroxyl groups to give 1-O-acetyl-4-thioarabinose (11), which was condensed with nucleobases to give 4'-thioarabinonucleosides. The 5-substituted-4'-thioaraU (6a-e) derivatives showed anti-HSV-1 activity (ED50 = 0.43-3.50 micrograms/mL). 4'-ThioaraG (6h) and 2,6-diaminopurine 4'-thioarabinonucleoside (4'-thioaraDAP, 6g) showed antiviral activity against several herpes viruses and were particularly potent against human cytomegalovirus (0.010 and 0.022 microgram/mL, respectively).

Antiviral Agents↗
PubMed1997

The ovarian renin-angiotensin system in reproductive physiology.

The identification of the presence of prorenin, renin, angiotensinogen, angiotensin-converting enzyme, angiotensin II (Ang II), and Ang II receptors in the ovary suggests that there is a functional ovarian renin-angiotensin system (RAS). It could play a significant role in such areas of ovarian physiology as follicular development, steroidogenesis, oocyte maturation, ovulation, and follicle atresia. Expression of the ovarian RAS is regulated by gonadotropins. Ang II, a bioactive octapeptide of RAS, has important effects as a paracrine/autocrine regulator at different stages of the reproductive cycle. Ang II modulates ovarian steroidogenesis and formation of the corpus luteum and also stimulates oocyte maturation and ovulation via Ang II receptors on granulosa cells. In addition, increasing evidence demonstrates that Ang II is a major factor in regulating the function of atretic follicles. In any physiologic system, aberrations result in the development of pathologic states. Disturbances in the ovarian RAS can be the cause or the result of such reproductive disorders as polycystic ovary syndrome, ovarian hyperstimulation syndrome, ovarian tumors, and ectopic pregnancy. Data support the concept of an active and regulated RAS in ovarian follicles. Species differences observed in the expression of ovarian RAS suggest varying functional roles among species with respect to ovarian physiology.

Angiotensin II↗
PubMed1997

Immunocytochemical localization of vitamin D receptors in the shell gland of immature, laying, and molting hens.

It is accepted that vitamin D is involved in the control of egg calcification in hens. The goal of this study was to localize the vitamin D receptors (VDR) in hen shell gland and to determine whether their localization was dependent on reproductive function. Frozen sections of the shell gland of immature, laying, and molting hens were immunostained for VDR, and the VDR in these tissues were also examined by Western blot analysis. Both apical and basal cells of the mucosal epithelium as well as tubular gland cells showed a strong immunoreaction for VDR in the shell gland of laying hens. In the magnum and isthmus, the basal cells of the mucosal epithelium showed a moderately strong immunoreaction for VDR, whereas the immunoreactions in the apical cells of the mucosal epithelium and tubular gland cells were weak. In the shell gland of immature birds, both the mucosal epithelium and tubular gland cells showed a moderately strong VDR immunoreaction. In molting hens, the mucosal epithelial cells and tubular gland cells showed a strong VDR immunoreaction although the mucosal tissue was regressed. Western blot analysis indicated that the mucosal tissue of the shell gland of immature, laying, and molting hens contained two forms of immunoreactive VDR, which were approximately 58 and 60 kDa. Because VDR were richer in the shell gland than in other oviductal segments, these results suggest that in laying hens the shell gland tissues are one of the significant targets for vitamin D. It is likely that the amount of shell gland VDR increases during sexual maturation and immunoreactive VDR remain even during the molting phase.

Animals↗
PubMed1997

Apoptosis in the development of the temporomandibular joint.

Apoptosis has been shown to be involved in remodeling of organs during development, and derangement of the apoptotic process may result in temporomandibular joint (TMJ) dysfunction or congenital malformation. To investigate the relationship between the development of the TMJ and apoptosis, rat fetuses at 17.5-20.5 days of gestation (E17.5-20.5, vaginal plug=E0) and rats at postnatal days 1, 2, 3, 5, and 10 (P1, 2, 3, 5, and 10) were examined by light (LM) and transmission electron microscopy (TEM) and electrophoretic analysis of DNA fragmentation. At E17.5 and 18.5, a few layers of slender mesenchymal cells which eventually develop into the TMJ disk were observed, although TEM or electrophoresis did not reveal apoptotic cells at these stages. At E19.5 and 20.5, all structures of the TMJ except the lower joint cavity could be distinguished, but at these stages apoptotic cells were not observed. In P1 condyles, apoptotic cells were observed by TEM both at the subsurface of the condyle and in the region at which the lateral pterygoid muscle attaches to the condyle. These apoptotic cells showed irregular chromatin condensation, convolution of the cell membrane, and fragmentation and disintegration of the cytoplasm. Electrophoretic analysis of the P1 condyle further confirmed DNA fragmentation. Apoptosis was not observed in all specimens at the P1 stage. It was confirmed in 8 out of 20 animals (10 out of 27 joints) by TEM and/or electrophoretic analysis. The shape of the upper portion of the condyle flattened progressively from E20.5 to P2. At this stage, the lower joint cavity was developing, as observed by LM. These findings suggest that the morphological changes of the mandibular condyle effected by apoptosis, together with development of the lower joint cavity, play important roles in the postnatal functional adaptation to external stimuli such as mechanical strain.

Animals↗
PubMed1997

"Crushed glass" appearance of particles observed in roentgenograms after hysterosalpingography as an indicator of pelvic abnormalities.

OBJECTIVE: To evaluate the diagnostic value of the crushed glass appearance of particles observed on roentgenogram after hysterosalpingography in patients with pelvic abnormalities. DESIGN: Retrospective study of 32 patients whose roentgenogram had particles with a crushed glass appearance and 16 patients without crushed glass appearance, with laparoscopy conducted to determine the location and severity of the pelvic disease. SETTING: Fujita Health University Hospital, Aichi, Japan. PATIENT(S): A total of 240 patients underwent hysterosalpingography to determine the cause of infertility. MAIN OUTCOME MEASURE(S): We compared the location of the pelvic endometriosis and/or inflammation that was observed on roentgenogram as the crushed glass appearance versus definitive findings at laparoscopy. RESULT(S): A total of 30 of the 32 cases (93.8%) with the crushed glass appearance were confirmed as having pelvic abnormalities, such as endometriosis (73.3%) and pelvic inflammation (26.7%). The rate of the concurrence of the location of the crushed glass appearance observed on the film and that of the lesions verified by laparoscopy was 66.7%. Histopathological examination showed that specimens taken from endometriosis or inflammatory lesions that comprised the crushed glass appearance were lacking in epithelium in proportion to the size of the particles. CONCLUSION(S): Identification of the crushed glass appearance of particles was a useful noninvasive method of detecting pelvic abnormalities, such as pelvic endometriosis and inflammation, in infertile women.

Adult↗
PubMed1997

Integrins and reproductive physiology: expression and modulation in fertilization, embryogenesis, and implantation.

OBJECTIVE: To review the available information regarding the role of integrins in reproductive physiology and to discuss their potential clinical implications. DESIGN: Studies that specifically relate to the expression and modulation of integrins in fertilization, embryogenesis, and implantation were identified through the literature and Medline searches. RESULT(S): Integrins are a class of adhesion molecules that participate in cell-to-cell and cell-to-substratum interactions and are present on essentially all human cells. All mammalian eggs express integrins at their surface, and the integrin alpha 6 beta 1 serves as a sperm receptor that mediates sperm-egg binding. In addition, certain integrin moieties appear to be regulated within the cycling endometrium. Specifically, the expression of beta 1 integrins in the early proliferative phase is restricted to the glandular epithelium, whereas stromal cells also express beta 1 integrins in the midsecretory phase. The expression of beta 1 integrins increases at the time of implantation and remains elevated in the decidua during early pregnancy. A disruption of integrin expression is associated with certain types of infertility in women. The apical surface of the mural trophectoderm does indeed possess functional integrins, and trophoblast interactions with extracellular matrix proteins largely depend on the integrin family of adhesion receptors. CONCLUSION(S): Integrins play particularly important roles in both fertilization and embryogenesis, including the process of implantation.

Animals↗
PubMed1997

Calcifying epithelioma (pilomatrixoma) of the head and neck: analysis of 37 cases.

OBJECTIVE: To review all cases of pilomatrixoma (calcifying epithelioma) of the head and neck published in Japanese dental journals 1977-1994. DESIGN: Retrospective review. SETTING: University hospital, Japan. SUBJECTS: 37 Patients with 38 tumours, mean age 23 years, female: male ratio 2.4:1. INTERVENTIONS: Enucleation alone (n=29, 78%), excision including covering skin (n=7, 19%), or excision including superficial lobe of parotid (n=1, 3%). MAIN OUTCOME MEASURE: Presentation, site, recurrence, and histological features. RESULTS: Two patients had multiple tumours (5%). Most of the tumours were firm nodules covered with normal skin varying in size from 5 to 30 mm. The most common site was the preauricular region; 22 (58%) were in the anterior part. The follow up period ranged from 7 to 43 months during which there was only one recurrence. Tumours were encapsulated and solid composed of either shadow and basophilic cells or shadow cells alone, and the stroma contained varying amounts of calcification, ossification, and keratinization. CONCLUSIONS: The diagnosis should be suspected when the mass is adherent to the skin but not fixed to the underlying tissue. It is difficult to distinguish between benign and malignant tumours by imaging methods alone, so the recommended treatment must be complete excision including adherent skin.

Adolescent↗
PubMed1997

Effect of KN-62, a selective inhibitor of calmodulin-dependent kinase II, on mouse oocyte activation.

PURPOSE: Our purpose was to determine the association of calmodulin-dependent protein kinase II (CaMKII) with oocyte activation and to explore the network of protein kinases during mammalian fertilization. METHODS: Mouse M-II oocytes were collected after superovulation induced by PMSG-hCG injection. The oocytes were inseminated or artificially activated by Ca ionophore (A23187) or 12-O-tetradecanoyl phorbol 13-acetate (TPA). The effects of KN-62, a specific and selective inhibitor of calmodulin-dependent protein kinase II, on second polar body emission (2PBE), pronuclear formation (PF), and cortical granule exocytosis (CGE) during fertilization or after artificial oocyte activation were investigated. RESULTS: KN-62 inhibited 2PBE and PF after sperm or Ca ionophore inducing activation. Additionally, PF was inhibited by KN-62 after TPA activation, whereas KN-62 did not inhibit CGE in any case. KN-04, an inactive form of KN-62, did not inhibit significantly 2PBE, CGE, or PF. When oocytes were exposed to KN-62 after Ca ionophore or TPA activation, no inhibitory effects on 2PBE or PF were observed. CONCLUSIONS: The CaMKII activation that occurs after fertilization or artificial activation of mouse oocytes is presumably secondary to increases in the intracellular free calcium concentration. As determined by the use of inhibitor, CaMKII activity is associated with 2PBE and PF but not with CGE.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1997

Reoperation of coronary artery bypass with right gastroepiploic artery on a beating heart.

The case of a 67-year-old male with double-vessel coronary artery disease combined with a severely calcified ascending aorta, moderate aortic insufficiency, cholecystic stones, and unruptured intracranial aneurysm is presented. Successful coronary artery bypass reoperation is described using the right gastroepiploic artery through an additional left anterior thoracotomy on the beating heart.

Aged↗
PubMed1997

Localisation of MHC class II, lymphocytes and immunoglobulins in the oviduct of laying and moulting hens.

1. Our aim was to determine the presence and numbers of immunocompetent cells in the oviduct of laying and moulting hens. Immunocompetent cells were localised by immunocytochemistry throughout the entire length of the oviduct. 2. In laying birds, MHC class II+ cells were observed in the subepithelial and middle part of the stroma of all oviducal segments and the mucosal epithelium of the infundibulum and vagina. CD3+ cells were also localised in subepithelial and middle part of stroma as well as in mucosal epithelium of each oviducal segment. Bu-lb+ and IgG+ cells were also observed in the epithelium and subepithelial and middle part of the stroma of all oviducal segments, though stroma of the magnum, isthmus and uterus contained few Bu-lb+ cells. IgA+ cells were observed only in the mucosal epithelium of the magnum in small numbers. 3. In moulting hens, there were few numbers of immunocompetent cells in the mucosal epithelium of each oviducal segment, although CD3+ cells were observed in the infundibulum and vagina. In the subepithelial stroma, the populations of MHC class II+ cells in the infundibulum, magnum and uterus, CD3+ cells in the infundibulum and vagina, as well as IgG+ cells in each oviducal segment except for isthmus were smaller than in laying hens. In contrast, the number of immunocompetent cells in the middle part of stroma of moulting hens were equal to or greater than in laying hens. 4. These results suggest that the oviducal immune function is active in the surface tissues of the mucosa in laying hens, whereas it is reduced in moulting hens.

Animals↗
PubMed1997

Changes in CA602 and CA546 concentrations in patients during in-vitro fertilization and embryo transfer, and ovarian hyperstimulation syndrome.

Changes in CA602 and CA546, two carbohydrate-related antigens newly established in our institute, were evaluated during the course of in-vitro fertilization and embryo transfer. The concentration of CA602, an antigen with characteristics similar to those of CA125, did not change substantially until embryo transfer. In patients with clinical evidence of ovarian hyperstimulation syndrome (OHSS), a significant increase in serum concentrations of CA602 was observed 10 days after embryo transfer (P < 0.01). There were no significant changes in the patients without OHSS. A significant elevation of oestradiol concentration in OHSS patients was also observed, with the variation before oocyte retrieval being greater than that seen with CA602. The concentration of CA546, which had lower false-positive rates in benign disease, did not differ significantly in the OHSS and non-OHSS patients. Our data demonstrate that serum concentrations of CA602 are increased even in early stages of OHSS, and suggest a possible role for this antigen as a marker for OHSS.

Adult↗
PubMed1997

Thioredoxin expression in the human endometrium during the menstrual cycle.

Human thioredoxin, a cellular disulphide reducing protein, is known to be secreted by some types of cells and to display unique extracellular activities including modulation of cytokine actions and protection of the cell against damage from oxidative stress. This study has been undertaken to investigate the pattern of expression and tissue distribution of thioredoxin in human endometrium during the menstrual cycle. Immunohistochemical studies showed increased thioredoxin immunoreactivity in the glands of the secretory phase compared to those of the proliferative phase. Although the staining of thioredoxin was relatively intense in predecidual stromal cells, the most prominent staining of thioredoxin was present in both glands and stroma of the endometrium in the early secretory phase of the menstrual cycle. Northern hybridization analyses revealed that expression of thioredoxin mRNA in the endometrium of the early secretory phase was approximately 3-fold compared to the other phases of the menstrual cycle, consistent with the results of the immunohistochemical studies. These results suggest that both protein and gene expression of thioredoxin in the endometrium are menstrual cycle phase-specific and highly active in the phase of endometrial differentiation which occurs in preparation for implantation (early secretory phase of the menstrual cycle). Thioredoxin expressed in the early secretory phase of the menstrual cycle may be advantageous for blastocyst implantation.

Endometrium↗
PubMed1997

Involvement of apoptosis and lysosomal hydrolase activity in the oviducal regression during induced molting in chickens: a cytochemical study for end labeling of fragmented DNA and acid phosphatase.

Induced molting improves egg producing functions in hens. We investigated the mechanism of oviducal regression during induced molting. Involvement of apoptosis and autolysis in the oviducal regression process was analyzed by terminal deoxynucleotidyl transferase (T'dt)-mediated biotinylated deoxyuridine triphosphates (dUTP) nick end-labeling TUNEL) and an enzyme histochemistry for acid phosphatase. Nuclei positive for TUNEL were negligible and acid phosphatase staining was weak in the oviduct of laying hens. The frequency of TUNEL-positive nuclei was significantly increased in tubular gland cells of magnum, isthmus, and shell gland 2 d after cessation of egg laying and significantly decreased thereafter. The intensity of acid phosphatase staining was gradually increased during oviducal regression and extremely high on Day 7 after cessation of egg laying. These results suggest that during oviducal regression in induced molting hens, apoptosis is induced in the earlier stage of oviducal regression and autolysis occurs thereafter eventually, the glandular cells disappear.

Acid Phosphatase↗
PubMed1997

Changes in the population of proliferating cells in chicken anterior pituitary during induced molting: an immunocytochemical analysis for proliferating cell nuclear antigen.

The goal of this study was to determine whether cell proliferation is increased in the anterior pituitary during an induced molting period in chickens. The anterior pituitaries were collected from: 1) laying hens before initiation of an induced molt (control hens), 2) molting hens 2 to 16 d after cessation of lay, and 3) second cycle laying hens 1 d after returning to lay. Pituitary cephalic and caudal lobes were processed for immunocytochemistry of proliferating cell nuclear antigen (PCNA), and positive cells were counted by an image analyzer using light microscopy. In cephalic and caudal lobes, a small number of positive cells were observed in controls and molting hens 2 d after cessation of lay. The frequency of PCNA-positive cells started to increase from 7 d after cessation of lay (3 d after refeeding), and a significantly higher frequency of positive cells was observed in both lobes of molting hens 13 d after cessation of lay when compared to control hens, molting hens 2 d after cessation of egg lay, and second cycle laying hens. The frequency of PCNA-positive cells in second cycle laying hens decreased to a similar level to that of control hens. These results suggest that anterior pituitary tissue may be remodeled partially by a proliferation of cells during induced molting in hens.

Animals↗
PubMed1997

Cell proliferation in the process of oviducal tissue remodeling during induced molting in hens.

Tissue remodeling and calcium binding protein-D28K (CaBP-D28K) dynamics were examined in the oviduct relative to induced molting. The oviducal tissues of premolting, 7, 10, 13, and 16 d after cessation of laying, and postmolting hens were examined. Frequency of proliferating cells and immunoreactive CaBP-D28K molecules were identified by immunocytochemistry for proliferating cell nuclear antigen (PCNA) and Western blot for CaBP-D28K. The relative frequency of PCNA-positive cells in the mucosal epithelium of the magnum, isthmus, and shell gland was low in premolting and 7 d after the cessation of egg laying. In the magnum and isthmus it was markedly increased in 10 and 13 d after cessation, followed by a slight decrease at 16 d after cessation. The frequency in the shell gland was kept high 10, 13, and 16 d after cessation. The frequency of PCNA-positive cells in each segment was decreased when the birds resumed laying. In the stroma of magnum and isthmus where the tubular glands were located, the frequency of PCNA-positive cells was significantly increased 10 d after the cessation of egg laying relative to premolting and 7 d after cessation. In postmolting hens and in hens 16 d after cessation, the frequency was decreased to a same level to that of premolting hen. In the shell gland, the frequency of PCNA-positive cells was high at 10, 13, and 16 d, and diminished in postmolting hen. Single immunoprecipitate band for CaBP-D28K was observed in the shell gland of premolting, postmolting, and younger hens, whereas the density of bands was greater in postmolting hens and younger hens than in premolting hens. We suggest that the oviducal tissues are remodeled by replacing the old glandular cells with new ones that are derived from the mucosal epithelium and uninvoluted glandular cells. Such rejuvenation of shell gland tissue may lead the improvement of CaBP-D28K induction.

Analysis of Variance↗
PubMed1997

Calcium independent contraction of bladder smooth muscle.

BACKGROUND: Recently, it has been suggested that in vascular smooth muscle a Ca(2+)-independent mechanism or Ca(2+)-sensitization of contractile elements may participate in smooth muscle contraction. In this study, we evaluate this mechanism in detrusor muscle. METHODS: Strips of smooth muscle from rabbit aorta, rabbit bladder and human bladder were evaluated by in vitro contraction studies. RESULTS: The results show that (1) in Ca(2+)-free solution containing ethyleneglycol bis (-aminothylether)-N,N,-tetraacetic acid (EGTA), carbachol and phorbol ester produced sustained contractions in detrusor muscle (Ca(2+)-free contraction); (2) depletion of Ca2+ stores by caffeine did not affect Ca(2+)-free contraction induced by carbachol; and (3) W-7 (calmodulin inhibitor) and ML-9 (myosin light chain kinase [MLCK] inhibitor) did not show inhibitory effects on Ca(2+)-free contraction, while H-7 (protein kinase C. [PKC] inhibitor) abolished this contraction. CONCLUSIONS: These results suggest that neither stored Ca2+ nor the Ca(2+)-calmodulin-MLCK system is involved in the carbachol-induced Ca(2+)-free contraction of detrusor muscle. This Ca(2+)-independent contraction seems to be mediated by the activation of PKC coupled with agonist stimulation of the muscarinic receptor.

Aged↗