Biomedical subjects

Ichiro Sakuma

Publications and source records attributed to Ichiro Sakuma.

59 records · Page 4Linked to original sources

PubMed2002

Role of ANG II in coronary capillary angiogenesis at the insulin-resistant stage of a NIDDM rat model.

With the use of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of human non-insulin-dependent diabetes mellitus (NIDDM), we assessed whether ANG II is involved in coronary capillary angiogenesis at the insulin-resistant stage of NIDDM (20 wk of age). In OLETF rats, ANG II labeling and angiotensin type 1 (AT(1)) receptor expression in coronary vessels were increased more than in nondiabetic controls. A marked increase in vascular expression of vascular endothelial growth factor (VEGF) at both mRNA and protein levels was found in OLETF rats. The increased expression level of VEGF was associated with accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) activated by increased advanced glycation end products (AGEs). Morphometric analysis showed a significantly increased total coronary capillary density, which was a result of arterialization of the venular capillary portion in OLETF rats. Treatment of OLETF rats with candesartan, an AT(1) receptor blocker, inhibited vascular expressions of VEGF, HIF-1alpha, and AGEs, and ameliorated the morphometric changes. These results suggest a key role of ANG II in the pathogenesis of the coronary capillary remodeling in this NIDDM model.

Angiotensin II↗

PubMed2002

Evidence for a potential role of estrogen in the penis: detection of estrogen receptor-alpha and -beta messenger ribonucleic acid and protein.

Body tissues are traditionally classified as estrogen targets based on both the response to the hormone and the presence of estrogen receptors (ERs). We undertook the study on expression of ERalpha and ERbeta in the penis to identify compartments/cells responsive to estrogen, using immunohistochemistry, Western blotting, in situ hybridization, and RT-PCR analyses. Expressions of ERalpha and ERbeta in the rat penis were age dependent at both mRNA and protein levels, with the most intense signals being observed during the perinatal period and declining thereafter with age. Initial signals (fetal d 17) of ERalpha were localized to the mesenchyme and subepithelial stroma and later (postnatal d 2) to the corpus spongiosus, corpus cavernosus, and urethral epithelia. ERbeta was initially detected by postnatal d 2 and was localized diffusely in corpus spongiosus and cavernosus in immature rats. In the adult, both ERs were concentrated largely to the urethral epithelia and vascular and neuronal structures. The present study provides the first evidence for ER expression in the penis. Thus, our data add the penis to the list of estrogen-responsive tissues in males and provide a base and insight for future studies aimed at investigating a functional role of estrogen in the penis, especially in development.

Aging↗

PubMed2002

[Hormone replacement therapy (HRT) for hyperlipidemia after menopause].

Women are about 10 years older than men to suffer from ischemic heart disease(IHD) and they often experience a sudden rise in cholesterol after menopause. These phenomena are thought to be caused by the production of estrogen in women during normal menstruation cycle and its loss after menopause. Hormone replacement therapy(HRT) has been shown to reduce IHD by nearly 50 per cent. This is caused in part by effects of estrogen on lipid metabolism; it reduces LDL and Lp(a), and increases HDL. Although the first large prospective trial of HRT for secondary prevention of IHD failed to demonstrate estrogen's protective effects, HRT was effective in women with high Lp(a). Thus, selection of patients and HRT regimen seems important.

Estrogen Replacement Therapy↗

PubMedDate not supplied

Cardioprotective effect of perfluorochemical emulsion for cardiac preservation after six-hour cold storage.

Perfluoro-octyl bromide (PFOB) emulsion is capable of transferring oxygen to tissues even at 4 degrees C, suggesting an application in myocardial preservation. We evaluated the cardioprotective effect of PFOB emulsion added to the storage solution. Guinea pig hearts were isolated (n = 24) and perfused with Krebs-Henseleit solution (KHS) and then cooled and perfused with St. Thomas Hospital II solution (STS). The hearts were stored in three different solutions: STS (STS group), oxygenated (O2) STS (O2 STS group), and O2 STS with PFOB emulsion (30%) (O2 STS + PFOB group) for 6 hours at 4 degrees C. After storage, rewarming was performed, followed by reperfusion with KHS. Left ventricular developed pressure of O2 STS + PFOB group was significantly higher than that of the other groups during reperfusion (p < 0.01). There was no difference among the three groups in O2 extraction and cardiac efficiency; however, cardiac oxygen consumption in the O2 STS + PFOB group significantly improved during reperfusion. In the O2 STS + PFOB group, creatinine kinase, lactate dehydrogenase, and myocardial water content were significantly decreased (p < 0.01). This study suggests that PFOB emulsion is beneficial for the cardioprotection of donor hearts, allowing a prolonged cardiac storage time.

Animals↗

PubMedDate not supplied

Feasibility study of imaging of intraductal papillary mucinous tumors of the pancreas based on integral photography.

BACKGROUND/AIMS: The principle of integral photography was first proposed by Lippman in 1908. Recently, the three-dimensional display system based on the principle of integral photography was developed. It projects three-dimensional objects using a lens array called a fly's eye lens and photographic film. Some groups have used it for surgical navigation in brain surgery. In this study, we tried to generate integral photographic images of intraductal papillary mucinous tumors of the pancreas, and evaluated the feasibility of this method. METHODOLOGY: Five patients with an intraductal papillary mucinous tumor of pancreas were studied. We used MRI data as three-dimensional data. MRI data were acquired with a 1.5-T clinical imager (Signal.5; GE Medical Systems, U.S.A). We used multi-slab single-shot fast spin-echo sequences. Section thickness was between 2 and 3mm in the coronal plane. From these data, integral photographic images were generated on a liquid crystal display by a three-dimensional rendering algorithm. RESULTS: Three-dimensional images using the principle of integral photography could be generated in all 5 cases. We could recognize these images as three-dimensional images by slightly moving the viewpoint to up, down, left, and right. From these images, we were able to grasp the three-dimensional relationship between the tumor, bile duct, and pancreatic duct. Using these three-dimensional images, a variety of minimally invasive surgical procedures were performed for intraductal papillary mucinous tumor of the pancreas, more safely and speedily than formerly. CONCLUSIONS: The images based on integral photography are suitable for medical imaging and are useful for surgical planning.

Adenocarcinoma, Mucinous↗