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Biomedical subjects

K Yoshioka

Publications and source records attributed to K Yoshioka.

At least 163 records · Page 9Linked to original sources
PubMed1998

Activin A and follistatin regulate developmental competence of In vitro-produced bovine embryos.

The effects of activin A and/or follistatin on the development of bovine embryos were investigated. Presumptive zygotes matured and fertilized in vitro were cultured in a chemically defined medium (modified synthetic oviduct fluid medium; mSOF). Addition of 1-100 ng/ml of activin A to mSOF significantly increased the percentage of zygotes that developed to morulae and blastocysts (48-54% and 31-41%, respectively) compared with no addition (41% and 25%, respectively). In contrast, addition of 1-100 ng/ml follistatin significantly reduced the percentage of zygotes developing to morulae and blastocysts (29-31% and 17-20%, respectively) compared with no addition (41% and 28%, respectively). In a culture with 10 ng/ml of activin A, supplementation with the same concentration of follistatin neutralized the positive effect of activin A, while supplementation with 100 ng/ml of follistatin reduced the percentage of zygotes that developed. The total cell numbers in morulae and blastocysts were not affected by the addition of activin A and/or follistatin. The development-enhancing effects of activin A and the development-impeding effects of follistatin were observed when embryos were exposed to activin A or follistatin at a concentration of 10 ng/ml prior to the 9- to 16-cell stage. These results suggest that activin A and follistatin may affect bovine embryos until the third cell cycle and may play important roles in regulation of the developmental competence of bovine embryos.

Activins↗
PubMed1998

Changes of ovarian structures, plasma LH, FSH, progesterone and estradiol-17 beta in a cow with ovarian cysts showing spontaneous recovery and relapse.

In a cow diagnosed as having ovarian cysts, we observed changes in the ovarian structures by ultrasonography for 71 days and examined plasma concentrations of sex hormones. The cow had 2 regressing cysts at the start of this study and 3 new follicles subsequently developed into cysts. With regression of these cysts, 2 new follicles developed and ovulated spontaneously, followed by the formation of 2 corpora lutea. On the day prior to ovulation, a preovulatory luteinizing hormone (LH) surge was detected. With regression of the corpora lutea, a new follicle developed and underwent atresia. Meantime, another follicle developed and became a cyst without ovulation. No preovulatory LH surge was observed during the period from regression of the corpora lutea to cyst formation. The results indicate that absence of the preovulatory LH surge is associated with occurrence of ovarian cysts and this endocrine aberration is reversible.

Animals↗
PubMed1998

Rhabdomyolysis after infection and taking a cold medicine in a patient who was susceptible to malignant hyperthermia.

A case of rhabdomyolysis after a possible viral infection and the use of a cold medication is reported. A 41-year-old man who presented with dysarthria, dysphagia, progressive weakness of his muscles and a high grade fever was admitted. He suffered from massive rhabdomyolysis, acute renal failure, and bronchopneumonia. Hemodialysis, antibiotics, and hydration therapy were effective in the treatment of his illness. Although the cause of the rhabdomyolysis was not completely clear, he was subsequently shown to be susceptible to malignant hyperthermia (MH) based on the results of a caffeine-halothane contracture test. When a mild recurrence occurred during a follow-up muscle biopsy, intravenous dantrolene sodium was administered and he improved immediately. This case suggests that MH should be considered in patients with rhabdomyolysis when the cause is unclear. The caffeine-halothane contracture test may also be helpful in the diagnosis.

Adult↗
PubMed1998

Peliosis hepatis associated with idiopathic restrictive cardiomyopathy.

A rare case of peliosis hepatis associated with idiopathic restrictive cardiomyopathy is reported. A 75-year-old man was admitted for evaluation of marked edema and jaundice. Serum total bilirubin was elevated above 20 mg/dl. The liver biopsy under laparoscopy revealed marked sinusoidal dilatation and retention of red blood cells, which was consistent with a diagnosis of peliosis hepatis. Cardiac catheterization revealed right ventricular filling disturbance without specific findings on endomyocardial biopsy, suggesting idiopathic restrictive cardiomyopathy. The level of serum total bilirubin decreased in association with improvement of edema after drip infusion of furosemide therapy.

Aged↗
PubMed1998

Glomerular charge and size selectivity assessed by changes in salt intake in type 2 diabetic patients.

OBJECTIVE: To evaluate glomerular charge selectivity in patients with type 2 diabetes, we studied changes in fractional clearance of proteins with different sizes and charges when patients were placed on two diets with different salt contents. RESEARCH DESIGN AND METHODS: Nineteen patients with type 2 diabetes and normoalbuminuria (< 20 micrograms/min, n = 8), microalbuminuria (20-100 micrograms/min, n = 7), or advanced albuminuria (> 100 micrograms/min, n = 4) were placed on a low-salt diet (85 mEq of sodium daily) or a high-salt diet (255 mEq of sodium daily) for 1 week, and then on the other diet, in random order. Fractional clearances of albumin and immunoglobulin G (IgG) were calculated on the last 3 days of each diet. RESULTS: In patients with normoalbuminuria, the high-salt diet increased the fractional clearance of IgG, which is electrically neutral, but the fractional clearance of albumin, which is anionic, was unaltered, suggesting that the pore charge of the glomerular barrier was unaffected. However, in patients with microalbuminuria, the high-salt diet increased the fractional clearances of IgG and albumin equally, indicating some neutralization of the pore charge. Fractional clearance of IgG in these first two groups was similar when salt intake was low, so pore size was the same in these groups. In patients with advanced albuminuria, fractional clearance of IgG was higher than in the other groups, indicating that size selectivity had worsened. CONCLUSIONS: In type 2 diabetic patients, charge selectivity is lost before size selectivity as diabetic nephropathy progresses.

Adult↗
PubMed1998

Honokiol induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to honokiol led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with honokiol. The fragmentation by honokiol of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition by honokiol of Molt 4B cells results from the induction of apoptosis in the cells.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Application of the human hepatitis B virus core antigen from transgenic tobacco plants for serological diagnosis.

BACKGROUND AND OBJECTIVES: The aim was to produce HBcAg from plants more cheaply than can be done by other currently available means, and to apply such antigen to immunoassay procedures for pretransfusion testing of donor blood. MATERIALS AND METHODS: Transgenic Nicotiana tabacum cv. SR-1 plants expressing the human hepatitis B virus (HBV) core antigen (HBcAg) gene were generated by Agrobacterium-mediated transformation. The recombinant product, called tHBcAg, can assemble itself into a spherical particle with a diameter of 25 to 30 nm, and can maintain two antigenic determinants of HBcAg, namely HBc/alpha and HBc/beta. Partly purified tHBcAg was used in the hemagglutination-inhibition (HI) test, as routinely used by the Japanese Blood Center, to test a panel of 524 blood units taken from HBV-positive donors. RESULTS: In the HI test, tHBcAg showed serologic properties comparable to that from Escherichia coli, the standard antigen used in the Japanese Blood Center. CONCLUSIONS: Transgenic plants can produce reagents for serologic testing and perhaps even such medical materials as oral vaccines.

Agrobacterium tumefaciens↗
PubMed1998

[Report management system using Web server and search engine].

PURPOSE: To develop a management system of written reports using a Web server and search engine. METHODS: All the reports written through word processing software in the local area network in the radiology department were automatically transferred to one of the PC servers, in which a Web server and search engine were in operation. Previous reports, approximately eighty thousand, were also registered. Using Web browsers and the program developed by hypertext mark-up language and JavaScript, all the reports were readily accessible by keywords, or by any words within reports. RESULTS: Over 100, 000 reports were easily accessible using Web browsers, based on our one-year experience. Maintaining the Web server and search engine, and upgrading the program were easily managed in our daily practice. CONCLUSION: The report management system we developed is flexible, scalable, and easy to maintain. It is an effective way to manage a large volume of radiology reports written through word processing software.

Computer Communication Networks↗
PubMed1998

[A modified method of cardiac functional analysis for ECG gated SPECT: study of functional G-maps].

To evaluate the cardiac function accurately using ECG gated SPECT images, we performed a modified method of cardiac functional analysis (Functional G-maps). One hour after the intravenous injection of 1,110 MBq of 99mTc-tetrofosmin, gated SPECT data was acquired dividing a cardiac cycle into 12 frames. Every short-axis images were usually reconstructed using first 11 of 12 frames. The reconstruction of these images was repeated performing slice thickness correction. Because the apex-to-base length is different at any frame during a cardiac cycle, 10 slices of short-axis images were obtained with the same thickness for each frame. Subsequently each short-axis image was divided by 40 radii, and the time activity curve was generated from the total counts included in each segment plus both neighboring segments. Afterwards the curve fitting was performed using the second reverse Fourier function. From fitted curves and their differentials, we estimated a variety of parameters including Max (End-systolic count), Min (End-diastolic count), %CI (Percent count increase), Uptake, PCR (Peak contraction rate), PDR (Peak distention rate) and CT (Contraction time). In 5 normal subjects, %Max was greater in the anterior and septal regions, whereas %Min was greater in the apex and lateral regions. %CI and %PCR were similarly greater in the septal, anterior and inferior regions. On the other hand, %PDR in the lateral or inferior region was lower than the values in the other regions. In conclusion, this modified method is expected to be useful for accurate assessment of regional cardiac function and myocardial perfusion.

Adult↗
PubMed1998

[Report of four cases of lymphocytic infundibuloneurohypophysitis].

We reported 4 cases of lymphocytic infundibuloneurohypophysitis. All four patients had diabetes insipidus as initial symptoms without anterior pituitary dysfunction. All patients showed pituitary stalk swelling and two patients showed enlargement of the pituitary gland. No patients were operated on for a histological diagnosis. No patients received corticosteroid treatment for this pathology. The mean follow-up period was 36 months. The diabetes insipidus continued in all cases, but radiological findings showed improvement in all cases. In one case, adrenal insufficiency occurred after 10 months, but had disappeared 6 months later. We think lymphocytic infundibuloneurohypophysitis can be diagnosed without histological examinations and can be treated conservatively without corticosteroid treatment. It seems to be a self-limiting disease. This disease can be distinguished from lymphocytic adenohypophysitis, but in some cases, both the anterior and posterior pituitary glands are invaded, and in this situation lymphocytic hypophysitis may be an appropriate name. Even if the initial symptom is diabetes insipidus, careful follow-up is needed for the duration of the disease.

Aged↗
PubMed1997

Activation of c-Jun N-terminal kinase during ischemia and reperfusion in mouse liver.

We have generated a mouse model for hepatic ischemia in which surgical subcutaneous transposition of the spleen allows hepatic ischemia to be applied without affecting other tissues. Using this mouse model we investigated the relationship between the length of ischemic periods in the liver and subsequent liver function; furthermore, we assayed the activation of c-Jun N-terminal kinase (JNK) during ischemia and reperfusion. Although prior to this study only the activated form of JNK was known to be translocated to the nucleus, we found that JNK translocates to the nucleus during ischemia without activation and is then activated during reperfusion. These results suggest a novel mechanism of JNK activation.

Animals↗
PubMed1997

Differential patterns of blastulation in bovine morulae cultured in synthetic oviduct fluid medium containing FCS or BSA.

This study examined the effects of fetal calf serum (FCS) supplementation of culture medium on blastulation and hatching of bovine morulae cultured in vitro. The presumptive zygotes derived from in vitro maturation and fertilization (IVM/IVF) were cultured in the modified synthetic oviduct fluid medium containing 3 mg/ml BSA (mSOF-BSA). At 120 h post insemination, morulae were randomly assigned to culture with mSOF-BSA (control) or mSOF containing 5% FCS (mSOF-FCS) instead of BSA. The replacement of BSA with FCS in mSOF significantly increased the percentage of blastocyst formation from Day 6 to Day 10 (Day 0 = the day of in vitro insemination) and the hatching rate of embryos on Days 8 and 9. The total number of cells in morulae and blastocysts on Day 6, in blastocysts on Day 7, and in blastocysts and hatched blastocysts on Day 8 were similar among the treatments. However, the replacement of BSA with FCS in mSOF significantly increased the total number of cells in hatched blastocysts on Day 10. Although the time of blastulation of embryos was significantly accelerated by the replacement of BSA with FCS in mSOF, the total number of cells in embryos at blastulation was lowered. The total number of cells in embryos at blastulation showed a time-dependent decrease when the embryos were cultured in mSOF-BSA. In contrast, the total number of cells in embryos that were cultured in mSOF-FCS depended little on the time after in vitro insemination. The results indicate that FCS supplementation of culture medium increased the percentage of embryos developing to the blastocyst stage without an increase in the total number of cells. However, an acceleration in the hatching rate and an increase in the total number of cells in hatched blastocysts were observed, compared with that in BSA-supplemented medium. It is suggested that FCS in the culture medium initiates earlier blastulation with fewer total numbers of cells in the morulae than BSA during in vitro culture of bovine embryos.

Journal Article↗
PubMed1997

A novel mechanism of JNK1 activation. Nuclear translocation and activation of JNK1 during ischemia and reperfusion.

Cytokines and various cellular stresses are known to activate c-Jun NH2-terminal kinase (JNK), which plays a role in conveying signals from the cytosol to the nucleus. Here we investigate the translocation and activation of JNK1 during ischemia and reperfusion in perfused rat heart. Ischemia induces the translocation of JNK1 from the cytosol fraction to the nuclear fraction in a time-dependent manner. Immunohistochemical observation also shows that JNK1 staining in the nucleus is enhanced after ischemia. During reperfusion after ischemia, further nuclear translocation of JNK1 is apparently inhibited. In contrast, JNK1 activity in the nuclear fraction does not increased during ischemia but increases significantly during reperfusion with a peak at 10 min of reperfusion. The activation of JNK1 is confirmed by the phosphorylation of endogenous c-Jun (Ser-73) with similar kinetics. The level of c-jun mRNA also increases during reperfusion but not during ischemia. Based on fractionation and immunohistochemical analyses, an upstream kinase for JNK1, SAPK/ERK kinase 1 (SEK1), is constantly present in both the nucleus and cytoplasm throughout ischemia and reperfusion, whereas an upstream kinase for mitogen-activated protein kinase, MAPK/ERK kinase 1, remains in the cytosol. Furthermore, phosphorylation at Thr-223 of SEK1, necessary for its activation, rapidly increases in the nuclear fraction during postischemic reperfusion. These findings demonstrate that JNK1 translocates to the nucleus during ischemia without activation and is then activated during reperfusion, probably by SEK1 in the nucleus.

Animals↗