Biomedical subjects

Y Okazaki

Publications and source records attributed to Y Okazaki.

At least 181 records · Page 10Linked to original sources

PubMed1995

Loss of heterozygosity in chromosomes 1, 5, 7 and 13 in mouse hepatoma detected by systematic genome-wide scanning using RLGS genetic map.

We have developed an RLGS-based scanning system to detect DNA alteration in tumor tissues, using 575 mapped spots/loci in a single gel. This system is very powerful for screening and identifying not only loss of heterozygosity (LOH) but also DNA methylation change. In this study, we applied this system to search for the LOH of hepatoma from an interspecific F1 hybrid between Mus spretus and C57BL/6 with SV40 early T antigen transgene connected to a mouse major urinary protein enhancer/promoter. Comparing the RLGS profiles of each tumor to that of the normal tissue showed significant LOH in chromosomes 1, 5, 7 and 13.

Animals↗

PubMed1995

Direct detection and isolation of restriction landmark genomic scanning (RLGS) spot DNA markers tightly linked to a specific trait by using the RLGS spot-bombing method.

We have developed a technique for isolating DNA markers tightly linked to a target region that is based on RLGS, named RLGS spot-bombing (RLGS-SB). RLGS-SB allows us to scan the genome of higher organisms quickly and efficiently to identify loci that are linked to either a target region or gene of interest. The method was initially tested by analyzing a C57BL/6-GusS mouse congenic strain. We identified 33 variant markers out of 10,565 total loci in a 4.2-centimorgan (cM) interval surrounding the Gus locus in 4 days of laboratory work. The validity of RLGS-SB to find DNA markers linked to a target locus was also tested on pooled DNA from segregating backcross progeny by analyzing the spot intensity of already mapped RLGS loci. Finally, we used RLGS-SB to identify DNA markers closely linked to the mouse reeler (rl) locus on chromosome 5 by phenotypic pooling. A total of 31 RLGS loci were identified and mapped to the target region after screening 8856 loci. These 31 loci were mapped within 11.7 cM surrounding rl. The average density of RLGS loci located in the rl region was 0.38 cM. Three loci were closely linked to rl showing a recombination frequency of 0/340, which is < 1 cM from rl. Thus, RLGS-SB provides an efficient and rapid method for the detection and isolation of polymorphic DNA markers linked to a trait or gene of interest.

Animals↗

PubMed1995

Alpha 1-adrenoceptor activation increases ecto-5'-nucleotidase activity and adenosine release in rat cardiomyocytes by activating protein kinase C.

BACKGROUND: Adenosine is an important regulator of many cardiac functions and is synthesized primarily by ecto- and cytosolic 5'-nucleotidase. We have previously reported that alpha 1-adrenoceptor blockade attenuates adenosine release from ischemic myocardium, raising the possibility that alpha 1-adrenoceptor activation activates 5'-nucleotidase. This study tested whether activation of protein kinase C by alpha 1-adrenoceptor activation increases 5'-nucleotidase activity and augments adenosine release. METHODS AND RESULTS: Cardiomyocytes were isolated from adult male Wistar rats and suspended in modified HEPES-Tyrode's buffer solution. After stabilization, the cardiomyocytes were incubated with and without an exposure to norepinephrine (10(-9) to 10(-5) mol/L) while being treated with propranolol and yohimbine or with and without an exposure to methoxamine (10(-9) to 10(-5) mol/L). Ecto-5'-nucleotidase activity was increased by norepinephrine and methoxamine during 30 minutes in a dose-dependent manner, whereas cytosolic 5'-nucleotidase was not activated. These increases in ecto-5'-nucleotidase activity were inhibited by GF109203X, an inhibitor of protein kinase C, and mimicked by phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C. The increase in ecto-5'-nucleotidase was not prevented by cycloheximide. When ecto-5'-nucleotidase activity increased, adenosine release was augmented in methoxamine- and PMA-treated cardiomyocytes (1299 +/- 252% and 1372 +/- 149%, respectively) compared with the untreated group (578 +/- 26%). The increase in adenosine release was blunted by GF109203X and alpha, beta-methyleneadenosine 5'-diphosphate, an inhibitor of ecto-5'-nucleotidase. CONCLUSIONS: Thus, we conclude that alpha 1-adrenoceptor-mediated increases in ecto-5'-nucleotidase activity are attributed to activation of protein kinase C in rat cardiomyocytes.

5'-Nucleotidase↗

PubMed1995

Accumulation of mercury in excavated bones of two natives in Japan.

Mercury content of excavated bones and surrounding soil was compared between the two areas of Shikoku, Tokushima and Matsuyama. Results show a high variance of mercury content between localities and between ages of the burials. There was a high mercury occurrence in the 6-7th century in Tokushima and a moderate one in Matsuyama, and a trace in the 12-17th century in both places. Moreover, a low level of mercury was observed in the soil samples of Tokushima, and mercury was not detected in any of the Matsuyama soil samples. Therefore, these occasions of high mercury content may be due to artificial uptake, and may relate to differences in conventions and customs.

Bone and Bones↗

PubMed1995

A case of advanced male breast cancer successfully treated by 5-fluorouracil, epirubicin and cyclophosphamide chemotherapy combined with tamoxifen.

A 79-year old male advanced breast cancer patient with metastases in lymph nodes, bones and anterior chest wall was effectively treated by a combination of chemotherapy (5-fluorouracil, epirubicin and cyclophosphamide), tamoxifen and minor surgery. Two months after five cycles of chemotherapy, all lymph node swellings disappeared. The main breast cancer and the chest wall metastatic nodule were resected under local anesthesia. He was maintained on tamoxifen alone and showed no lymph node recurrence during the follow up period of 20 months, suggesting good control of bone metastatic lesions.

Aged↗

PubMed1995

An expanded system of restriction landmark genomic scanning (RLGS Ver. 1.8).

The restriction landmark genomic scanning (RLGS) method is a high-speed genome scanning system which is based on the concept that restriction enzyme sites can be used as landmarks throughout the genome. It employs direct end-labeling of the genomic DNA digested with a rare-cutting restriction enzyme, followed by high-resolutional two-dimensional electrophoresis. Recently, this system was further developed to lower cost and to simplify the procedure. This paper reviews the RLGS principle and the breakthroughs enabling its further development. Also presented is the precise protocol of the newest version (RLGS Ver. 1.8) that offers cost effectiveness and an expanded production system. Finally, the advantages of this new RLGS method and prospects for its widespread application are discussed.

Animals↗

PubMed1995

A spot cloning method for restriction landmark genomic scanning.

We introduce two new methods for target cloning of DNA fragments corresponding to spots on the two-dimensional profile of restriction landmark genomic scanning (RLGS). One is a restriction trapper-based method and the other is a polymerase chain reaction (PCR) mediated method. Both are designed to select the target DNA fragments from a large amount of unlabeled background DNA fragments in the RLGS gel which produce background clones. The restriction trapper method is simple, with a cloning efficiency that is not biased by the length of the target DNA nor by its GC content. On the other hand, the PCR-mediated method is efficient for cloning DNA fragments from a small amount of starting materials. These methods provide us with powerful tools for isolating DNA clones identified by the RLGS system as interesting spots. This paper reports the precise protocols of these methods and discusses their application and usefulness.

Animals↗

PubMed1995

Genetic mapping of restriction landmark genomic scanning loci in the mouse.

Restriction landmark genomic scanning (RLGS) was originally proposed as a high-speed method for surveying a large number of restriction landmarks in genomic DNA. The effort to apply this method to genetic analysis has been made, resulting in developing the new approach for the rapid construction of the genetic map of complex mammalian genomes (RLGS spot mapping). Especially, the use of NotI as the restriction landmark for genetic studies suggests that there is a high probability that a significant number of these RLGS loci will be associated with CpG islands of functional genes. Moreover, it is possible to use the RLGS spot mapping to analyze genetic map-poor species very rapidly for linkage of recessive mutations or segregating traits, because it does not rely upon cloned probes or sequences. In this paper, we summarize the progress that has been made in the practical application of the RLGS method to genetic analysis using congenic strains, recombinant inbred (RI) strains, and in interspecific backcrosses of mice.

Animals↗

PubMed1995

A single gel analysis of 575 dominant and codominant restriction landmark genomic scanning loci in mice interspecific backcross progeny.

We identified 575 new NotI landmarks of C57BL/6(B)- and M. spretus (S)-specific, dominant and codominant loci which were segregated in B x S interspecific backcrosses (BSS), using the restriction landmark genomic scanning (RLGS) spot mapping method. All of these loci were visualized on a single RLGS profile which was produced with NotI-PvuII-PstI. These landmarks include 250 newly identified S-specific spots in addition to the previously reported 325 B-specific spots. The S-specific spots were identified by reading full or half intensity, based on the property that the spot intensity of the autoradiographic signal reflected the copy number of an end-labeled restriction landmark. The cumulative map is 1341 cM and it is based upon 985 meiotic events in 72 backcross progeny. This map covers 90% of the total estimated length of the mouse genetic map. This map provides a good tool for the high-speed genome scanning assay in the mouse genome by a single RLGS gel analysis.

Animals↗

PubMed1995

In vitro biocompatibility, mechanical properties, and corrosion resistance of Ti-Zr-Nb-Ta-Pd and Ti-Sn-Nb-Ta-Pd alloys.

There is much discussion about the toxic effect of vanadium and aluminum contained in Ti-6Al-4V alloy for prosthetic implants. The goal of the present investigation was to develop new titanium alloys with sufficient mechanical properties using more biocompatible alloying elements: zirconium, tin, niobium, tantalum, and palladium. The relative growth rates of L929 and MC3T3-E1 cells were significantly higher when cultured with the extraction of Ti-10Zr-8Nb-2Ta-0.2Pd or Ti-15Zr-4Nb-2Ta-0.2Pd alloys than when cultured with the extraction of Ti-6Al-4AV ELI alloy. The tensile strength, elongation, and reduction of area for Ti-15Sn-4Nb-2Ta-0.2Pd alloy were 989 MPa, 14.4%, and 49.3%, respectively, surpassing Ti-6Al-4V ELI alloy. (ASTM F138-84); those for Ti-15Zr-4Nb-2Ta-0.2Pd alloy were 725 MPa, 23.6% and 54.9%, respectively. More than 15% addition of tin as well as zirconium deteriorated the tensile properties. Titanium release into a 5% hydrochloric acid solution from the new titanium alloys was 20-50 micrograms/cm2 per day, though that from Ti-6Al-4V ELI alloy was 1300 micrograms/cm2 per day. The optimum alloy compositions are Ti-15Zr-4Nb-2Ta-0.2Pd and Ti-15Sn-4Nb-2Ta-0.2Pd, judging from cytocompatibility, corrosion resistance, and mechanical properties. The former is characterized by its higher level cytocompatibility and corrosion resistance, while the latter is characterized by mechanical properties.

Alloys↗

PubMed1995

Accumulation of hydroxyapatite in the kidney of streptozotocin-induced diabetic rat fed a low-zinc diet.

Calcification occurred in the kidney of streptozotocin (STZ)-induced diabetic rats fed a low-zinc diet. The deposits were stained by the von Kossa method and were detected intracellularly in the tubular cells, mainly in the cortico-medullar region. The deposits were found to be a heterogenous substance on electron microscopy. There were various sizes of deposits, and the surfactant was very much distorted. Many deposits grew up to bind small particles, and the core-like substance was observed in the center of the deposit. The component of the deposit was analyzed by an X-ray microanalyzer, and was found to be calcium and phosphorus. The ratio of calcium to phosphorus was 2.159, which coincided with the ratio of standard hydroxyapatite. From these observations, the deposit is believed to be hydroxyapatite. It is thought that the core is formed at first, many particles are then bound to the core, and deposits grow up.

Animals↗

PubMed1995

Comparison of three different methods for measurement of tissue platinum level.

We attempted to make a comparison of three methods for tissue platinum; atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and inductively coupled plasma mass spectrometry (ICP-MS). The determination limits were 0.05 ng/mL on ICP-MS, 50 ng/mL on ICP-AES, and 200 ng/mL on AAS, and the recovery rates were 97.7 +/- 6.9% on ICP-MS, 69.0 +/- 3.0% on ICP-AES, and 102.4 +/- 4.0% on AAS, respectively. Platinum was detected by ICP-AES and ICP-MS in human vertebrae, but the level was higher by ICP-AES than by ICP-MS. In the mouse kidney treated with cisplatin, platinum was detected by ICP-MS, but not by ICP-AES. As cadmium gives the absorption peak close to platinum, cadmium was measured together with platinum by ICP-AES in the vertebrae. From these, ICP-MS is the most sensitive for measurement at tissue platinum. The sensitivity of ICP-AES looks worse for measuring the tissue platinum, and it is necessary to take care of the contaminant of metals, especially cadmium. AAS is not suitable for measurement of tissue platinum as in the vertebrae and kidneys, because platinum was not detectable by AAS.

Adenocarcinoma↗

PubMed1995

Effect of eicosapentaenoic acid and docosahexaenoic acid on diabetic osteopenia.

To evaluate the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are polyunsaturated fatty acids, on diabetic osteopenia, we measured the bone fragility in streptozotocin-induced diabetic rats. The fragility of femur was increased in diabetic rats, which was prevented in part by EPA or DHA. Moreover, EPA prevented osteopenia even in diabetic rats fed a low zinc feed, which was a potent accelerator of diabetic osteopenia. Plasma alkaline phosphatase activity and parathyroid hormone level showed no difference between the two groups of diabetic rats with or without EPA. Urinary excretion of calcium and phosphate was increased and plasma inorganic phosphate level was high in diabetic rats, suggesting severe mineral loss. In diabetic rats fed EPA, although urinary and plasma calcium levels did not change significantly, urinary phosphate excretion and plasma inorganic phosphate concentration were slightly lowered, which suggested that EPA may have an effect in suppressing phosphate release from bones in diabetic rats. These data suggest that EPA and DHA could be effective on diabetic osteopenia, but to elucidate the precise mechanisms, further examinations will be needed.

Alkaline Phosphatase↗

PubMed1995

Chronic contained rupture of an abdominal aortic aneurysm.

The operative treatment of chronic contained rupture of a saccular abdominal aortic aneurysm (AAA) with retroperitoneal haematoma is reported. A 62-year-old man presented with a painless abdominal mass and intermittent claudication. He had an episode of severe abdominal pain about 2 years before admission. A giant retroperitoneal neoplasm was initially suspected, based on computed tomography. However, magnetic resonance imaging, angiography and colour Doppler sonography demonstrated chronic contained rupture of an AAA. A punched-out oval defect (width 3.5 cm x length 4.5 cm) that was thought to connect the thrombosed aneurysm to an organized retroperitoneal haematoma was discovered in the posterior wall of the bifurcation of the aorta at laparotomy. An infrarenal aortobiexternal iliac Y-graft with bypass to the left femoral artery was placed without removing the aneurysm or haematoma. Recovery was uneventful. The retroperitoneal haematoma appeared smaller on computed tomography about 1 year after operation. This case fulfilled the criteria for chronic contained rupture of an AAA proposed by Jones and associates.

Aortic Aneurysm, Abdominal↗

PubMed1995

Downward shift of coronary pressure-flow relationship following a brief period of ischemia in dogs.

This study was undertaken to test whether a brief period of ischemia affects the coronary pressure-flow relationship during reduction of coronary perfusion pressure (CPP). The left anterior descending coronary artery was cannulated and perfused with blood from the left carotid artery in 40 open-chest dogs. Coronary blood flow (CBF) was measured during intracoronary administrations of papaverine and adenosine. The coronary pressure-flow relationship was assessed during transient reduction of CPP from 100 to 30 mmHg. Coronary hyperemic flow due to adenosine and papaverine was attenuated 30 min after transient 10- and 15-min periods of ischemia. In the group of transient 10-min ischemia, both fractional shortening (FS) and CBF returned to the preischemic values at 30 and 60 min of reperfusion; however, marked decreases in CBF (35 +/- 5 vs. 56 +/- 4 ml.100 g-1.min-1 at CPP = 60 mmHg, P < 0.01) during graded reductions in CPP were observed. The endomyocardial blood flow was reduced relative to the control condition. Furthermore, both FS (6 +/- 1 vs. 14 +/- 1% at CPP = 60 mmHg, P < 0.01) and lactate extraction ratio (-41 +/- 15 vs. 1 +/- 6% at CPP = 60 mmHg, P < 0.05) were decreased. The downward shift of the CPP-CBF relationship and the deterioration of myocardial contractile and metabolic function during reduction of CPP were restored 60 min after the onset of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗

PubMed1995

Symptoms of psychoses. A factor-analytic study.

BACKGROUND: The literature on the statistical analysis of symptoms of psychoses was limited to positive and negative symptoms in schizophrenia. The present study explored the relationship between positive and negative symptoms as well as affective symptoms in a wider category of psychotic disorders. METHOD: The symptoms of 584 psychiatric patients, consecutively admitted to any of the 95 mental hospitals in Japan, were studied. They manifested at least one of the following: (a) delusions, (b) hallucinations, (c) formal thought disorder, (d) catatonic symptoms, or (e) negative (defect) symptoms. RESULTS: Factor analysis yielded five factors interpretable as (a) manic symptoms, (b) depressive symptoms, (c) negative (defect) symptoms and formal thought disorders, (d) positive (psychotic) symptoms, and (e) catatonic symptoms. CONCLUSION: These results suggest that although major symptoms seen among psychotic patients can be categorised into positive, negative, manic, and depressive groups, corresponding to current knowledge of phenomenology, catatonic symptoms constitute a discrete syndrome, while formal thought disorders merge into the negative syndrome.

Adolescent↗

PubMed1995

Relationship between age and nephrotoxicity following single low-dose cisplatin (CDDP) injection in rats.

We studied nephrotoxicity following a single injection of cisplatin (CDDP) at low dose (1 mg/kg) in two groups of rats aged 52 weeks (adult, A group) and 9 weeks (young, Y group). Renal platinum (Pt) was detectable in both groups 3 h after the CDDP injection, and, from 6 h to 3 d after injection, its level in the A group was higher than that in the Y group. Compared with the levels in age-matched normal rats (non-treated rats examined at time zero), the plasma urea nitrogen and creatinine levels in the A group were significantly increased, beginning 3 d after CDDP injection, while those in the Y group showed little change for 10 d after injection. Beginning 3 d after CDDP injection, the level of renal metallothionein in the Y group increased, while that in the A group decreased remarkably. The renal tissue levels of the heavy metals Zn, Cu, Mn showed similar patterns. There were no significant changes in the renal lipid peroxide (LPO) level in either the A and Y group at any time measured after CDDP injection compared with the value in the respective age-matched untreated group. Morphological evaluation demonstrated degeneration of the proximal tubules in the A group 3 d after CDDP injection. These results suggested that the renal disorders observed following CDDP injection in the A group were caused by mechanisms other than LPO such as decreased tissue metabolic function associated with aging.

Aging↗

PubMed1995

Renal changes of streptozotocin-induced diabetic rats fed a low-zinc diet.

The changes in kidneys of streptozotocin (STZ)-induced diabetic rats fed a low-zinc (LZ) diet were observed. Calcium deposits were detected in the LZ-diabetic groups from the 2nd to the 8th week. The deposits were mainly detected in the corticomedullary junction, and found in the tubular lumina and epithelial cytoplasm and interstitium. Tubular morphological changes, including luminary distension, epithelial flattening, and paleness of cytoplasm and nuclei, were observed near the calcium deposits in the LZ-diabetic group over the 2nd week. Moreover, at the 8th week, wedge-shaped vasogenic lesions were found on the surface of the renal cortex in the LZ-diabetic group. No changes were detected in the control for the LZ or in the diabetic group fed a standard (SC) diet. When STZ was administered, plasma glucose level in groups fed LZ or SC diet increased in the 1st week, and over the 2nd week, glucose level was maintained at more than 400 mg/dL. Glucose level of the LZ-diabetic group did not differ from that of the SC-diabetic group. However, urinary N-acetyl-beta-D-glucosaminidase activity of the LZ-diabetic group at the 8th week was significantly higher than that of the SC-diabetic group. These findings suggested that low-zinc diet hastens renal damages in diabetic rats.

Animals↗