Biomedical subjects

S Ohtani

Publications and source records attributed to S Ohtani.

At least 19 recordsLinked to original sources

PubMed1998

Expression and distribution of brain natriuretic peptide in human right atria.

OBJECTIVES: We investigated expression of brain natriuretic peptide (BNP) as well as atrial natriuretic peptide (ANP) and their genes in human right atria. Their relations with atrial pressure were also examined. BACKGROUND: The BNP plays a roll in electrolyte-fluid homeostasis such as ANP. The tissue level is reported to be elevated in the failing ventricles. However, expression and transmural distribution of BNP in the atria remain unclear. METHODS: Expression of ANP and BNP was immunohistochemically investigated in the right atrial (RA) specimens from 21 patients who had undergone cardiac surgery. The mRNA of specimens were quantitatively measured by Northern blot analysis and also evaluated by in situ hybridization. In addition, plasma levels of ANP and BNP were measured in the patients. RESULTS: The BNP immunoreactivity was diffusely seen in RA tissue of patients with mean RA pressure (mRAP) of 5 mm Hg or more, but it was noted only in the subendocardial half of the atria of those with mRAP less than 5 mm Hg. There was a significant correlation between the incidence of BNP-positive myocytes and mRAP (r = 0.850, p < 0.0001). Conversely, ANP-positive myocytes were found diffusely in all cases. In Northern blot analysis, the mRNAs levels of ANP and BNP in the atrial tissue were positively correlated with the mRAP (ANP, p = 0.775, p < 0.005 and BNP, p = 0.771, p < 0.005). In situ hybridization confirmed these findings. The mRNA levels were significantly correlated to each other (r = 0.845, p < 0.0002). Plasma ANP and BNP levels were elevated in the patients compared with that in controls; however, none were significantly correlated with the mRAP. CONCLUSIONS: Expression of BNP and BNP mRNA is augmented in the atria with increased pressure, and distributed predominantly in the subendocardial side. The level of BNP mRNA was well correlated with that of ANP mRNA. Thus, these two genes might be commonly regulated in response to atrial pressure.

Aged↗

PubMed1998

Purification and characterization of myonase from X-chromosome linked muscular dystrophic mouse skeletal muscle.

A chymotrypsin-like proteinase, designated myonase, was successfully purified to homogeneity from X-chromosome linked muscular dystrophic mouse skeletal muscle by affinity chromatography on agarose conjugated with lima bean trypsin inhibitor as ligand. The molecular mass of the purified myonase was determined to be 26 kDa by SDS-PAGE and to be 25,187 Da by mass spectrometry. The native enzyme is a single chain molecule and a monomeric protein without sugar side-chains. The nucleotide sequence of myonase mRNA is similar to mouse mast cell proteinase 4 (MMCP-4) cDNA. This is the first report of a native enzyme whose amino acid sequence closely corresponds to MMCP-4 cDNA. Myonase has chymotrypsin-like activities and hydrolyzes the amide bonds of synthetic substrates having Tyr and Phe residues at the P1 position. Myonase is most active at pH 9 and at high concentration of salts. Myonase preferentially hydrolyzes the Tyr4-Ile5 bond of angiotensin I and the Phe20-Ala21 bond of amyloid beta-protein, and it is less active towards the Phe8-His9 bond of angiotensin I and the Phe4-Ala5 and Tyr10-Glu11 bonds of amyloid beta-protein. Myonase is completely inhibited by such serine proteinase inhibitors as chymostatin, diisopropylfluorophosphate and phenylmethylsulfonyl fluoride, but not by p-tosyl-L-phenylalanine chloromethyl ketone, p-tosyl-L-lysine chloromethyl ketone, pepstatin, E-64, EDTA, and o-phenanthroline. It is also inhibited by lima bean trypsin inhibitor, soy bean trypsin inhibitor, and human plasma alpha1-antichymotrysin. These properties match those of chymase, but unlike chymase, myonase does not interact with heparin in the regulation of its activity. Myonase was immunohistochemically localized in myocytes, but not in mast cells.

Amino Acid Sequence↗

PubMed1998

Improvement of age estimation using amino acid racemization in a case of pink teeth.

Age was estimated from pink teeth using racemization of dentinal aspartic acid. Materials for identification were two lower second premolars. The body was determined to be that of a 40-year-old man; however, the age of the decedent had been estimated to be 29 and 30 years by the conventional method and 30 years from findings in the oral cavity. To clarify the cause of this difference, the powdered teeth were further washed in 0.01 mol/L hydrochloric acid. The racemization ratio (D/L ratio) of ordinary white teeth from persons of known age was slightly lower than that before washing, whereas that of the teeth used for identification was higher than before washing. The calculated age of the decedent using the racemization ratio of his teeth was between 36 and 37 years. These results suggest that age estimated from pink teeth is probably underestimated, but a more accurate age estimate can be obtained after adequate washing.

Adult↗

PubMed1998

Rate of aspartic acid racemization in bone.

There are no reports on rates of amino acid racemization in bones. To investigate the possibility of estimating age by evaluating amino acid residue racemization in human bones, a heating experiment was performed and the rate of aspartic acid racemization was determined using the Arrhenius equation. Assuming an annual mean temperature of 15 degrees C, the rate constant (k) for aspartic acid racemization in bone was calculated, and the racemization rate at 15 degrees C k (y) was 4.1036 x 10(-9)--much lower than that of dentin. These results suggest that it is more difficult to accurately determine age by analyzing aspartic acid residues in bone than in dentin.

Adult↗

PubMed1998

Localization of pNT22 70 kDa heat shock cognate-like protein in the plasma membrane.

It has been argued that 70 kDa heat shock cognate (hsc73)-like molecules may be expressed on the surface of certain cells, but direct evidence of this has yet to be found. To clarify whether this molecule belongs to hsc73 itself, the membrane protein fraction of Daudi cells was isolated by Triton X-114 phase separation and the reactivity of this membrane protein fraction was assessed with monoclonal antibodies (mAbs) which react with 70 kDa heat shock protein (hsp) family, i.e., NT22, A15 and 3A3. In western blotting analysis, mAb NT22-defined protein (pNT22) was clearly detected as a membrane protein of Daudi cells with an approximate molecular size of 70 kDa, whereas pNT22 was not recognized by anti-cytoplasmic hsc73/hsp72 mAbs A15 or 3A3. By using deleted recombinant hsc73 proteins, it was determined that mAb NT22 recognizes the N-terminal 350-372 amino acid stretches of the hsc73 protein. mAb NT22 also reacted with the cell surface protein of Daudi cells in FACS analysis. Taken together, our present data strongly suggest that pNT22 may be a novel hsc73-like protein that is localized in the plasma membrane.

Antibodies, Monoclonal↗

PubMed1998

Expression of heat shock protein after ischemic preconditioning in rabbit hearts.

Previous studies have shown that preconditioning (PC) with a brief ischemic episode induces heat shock protein (HSP) in cardiac tissue. However, it is unclear when and where in the left ventricle HSP is expressed after PC. Hence, the expression of HSP was studied in rabbit hearts at various time intervals after PC using immunohistochemical methods. Rabbits were preconditioned four times with 5 min of occlusion and 5 min of reperfusion of the coronary artery and then were killed at 0, 3, 24, 48, 72 and 168 h after the PC (n=4, for each time interval). Samples were obtained from the subendocardium and subepicardium of the preconditioned and nonpreconditioned wall and these were processed to 4 microm thick cryosections. The sections were immunolabelled with mouse monoclonal IgGs against HSP 72/73. Positive immunoreactivity was observed as early as 3 h after PC, persisting up to 72 h but not detected at 168 h. HSP was expressed not only in the preconditioned myocardium but also in the remote nonpreconditioned myocardium. There was a wide variation in expression among myocytes. Expression was dominant in myocytes compared with vessel walls. It was concluded that PC induced transient and inhomogeneous expression of HSP in rabbit hearts.

Animals↗

PubMed1998

Changes in the amount of D-aspartic acid in the human femur with age.

The amount of D-aspartic acid (D/L ratio) among total amino acids, acid-insoluble collagen, and non-collagen proteins (acid-soluble peptides) from the human femoral compact substance was measured by gas chromatography. We found that the amount of D-aspartic acid increased linearly with age in males but not in females. This difference between the sexes may be related to the sex differences in hormonal circumstances to the fact that osteopathy is more common in females than in males. The D/L ratio in total amino acids varied with the size of the bone fractions, being higher in large ones. The D/L ratio in acid-soluble peptides varied with the size of the powder particles from which they had been extracted, and was also higher in large particles. It is concluded that D-aspartic acid in the femoral compact substance increases with age only in males.

Adolescent↗

PubMed1998

Evaluation of aspartic acid racemization ratios in the human femur for age estimation.

Levels of D-aspartic acid (D/L ratio) in cranial non-collagen proteins (acid-soluble peptide fractions) have been reported to increase with age. We isolated total amino acid fractions from the femur and separately isolated acid-insoluble collagen fraction and acid-soluble peptide fractions; then D/L ratios were measured from each fraction by gas chromatography. We evaluated the applicability of their D/L ratios for age estimation based on their correlation coefficient. A sex-related difference was observed in the D/L ratio. In particular, aged females showed a low ratio, suggesting an association with bone disorders. In males, the D/L ratios of acid-soluble peptide fraction showed the highest correlation rate (r = 0.969) with age, and those of total amino acid fraction showed the highest correlation rate (r = 0.633) with age in females. Without separation of male and female, the D/L ratios of total amino acid fraction showed the highest value (r = 0.853). The D/L ratio of acid-soluble peptide fractions differed according to the size of bone powder particles, being higher for larger particle sizes. These results suggest that the application of D/L ratio from total amino acid fraction is the most effective method for estimating age using the human femur. However, care is necessary when studing cadavers that might be females.

Adolescent↗

PubMed1997

Expression of ubiquitin protein in each organ at death from hypothermia.

To examine the expression of heat shock protein (hsp) in each organ on autopsy in 11 deaths from hypothermia, we performed immunological staining of specimens from each organ using an antibody to hsp, ubiquitin (Ub). Staining of the liver, kidneys, lungs and pancreas revealed a high level of Ub expression in the cytoplasm and nuclei. However, staining of the same specimens of all controls revealed no Ub expression in the cytoplasm or nuclei. This finding suggests that cells are affected by stress even at a low temperature, and may be important in clarifying the cellular kinetics in death from hypothermia.

Adult↗

PubMed1997

False aneurysm of the axillary artery caused by graft infection: report of a case.

A 77-year-old man presented to our hospital following the sudden onset of left subclavicular swelling, 8 years after undergoing subtotal removal of an axillofemoral bypass. Computed tomography revealed a rupture of the left axillary artery with the formation of a false aneurysm. Emergency surgery was performed in the form of an extraanatomic, axillo-axillary bypass with resection of the false aneurysm. Prior to removal of the false aneurysm, the subclavian artery was ligated via a left thoracotomy to minimize blood loss. The pathogen was identified as Proteus mirabilis, which is a rare causative organism for prosthetic graft infection. This case report demonstrates that total removal of the graft with revascularization should be performed for graft infections.

Aged↗

PubMed1997

The argyrophilic nucleolar organizer region (Ag-NOR) score in invasive ductal carcinoma of the pancreas.

The biological malignancy of pancreatic carcinoma was evaluated by determining the score of the argyrophilic nucleolar organizer region (Ag-NOR) in resected specimens, and comparing it with the various clinicopathological factors and long-term results of 38 patients who underwent surgical resection for invasive ductal carcinoma of the pancreas between 1977 and 1992, in whom the Ag-NOR could be stained. The Ag-NOR analysis of pancreatic carcinomas from the 38 patients resulted in a mean Ag-NOR score of 3.82 +/- 0.62, which was significantly (P < 0.01) higher than the mean score of 1.72 +/- 0.28 observed in normal pancreatic tissues obtained from 20 of these patients. The mean Ag-NOR score significantly increased in patients with anterior capsular infiltration (s) (P < 0.01), posterior tissue infiltration (rp) (P < 0.01), and lymph node metastasis (n) (P < 0.05) compared to those without these factors. The rate of curability A or B was only 13.0% in patients with a high Ag-NOR score of > or = 3.80 in comparison to 66.7% in those with a low Ag-NOR score of < 3.80. The 3-year survival rate was significantly (P < 0.05) higher in the low Ag-NOR score group than in the high Ag-NOR score group. These results suggest that the Ag-NOR score can serve as an indicator of the biological malignancy of pancreatic carcinoma, and of the patients' prognosis.

Carcinoma, Ductal, Breast↗

PubMed1997

Effects of dietary fat sources on lipid metabolism in growing chicks (Gallus domesticus).

The effect of dietary fat sources with different degrees of unsaturation and double bond positioning on lipid metabolism was studied in growing chicks. Four-week-old chicks were given semi-purified diets containing 6% palm oil (PLO), 6% safflower oil (SFO), 3% safflower oil and 3% linseed oil (SFO + LNO), 6% linseed oil (LNO), or 3% linseed oil and 3% fish oil (LNO + FO) with 0.5% cholesterol supplementation. Cholesterol ester content in the liver and serum of chicks fed PLO diet was significantly higher than that of other diet groups. Liver triacylglycerol and free cholesterol contents were significantly decreased in chicks fed a diet containing n-3 fatty acids (i.e., linseed oil or fish oil). Serum triacylglycerol level was also decreased by feeding the LNO or LNO + FO diet. The activity of serum lecithin-cholesterol acyltransferase was not affected by dietary treatments. Fecal neutral steroid excretion was significantly increased in the LNO+FO diet group as compared with the SFO + LNO or LNO diet groups. With the increase in linseed oil levels, the levels of C18:2n6 and C20:4n6 fatty acids in tissue lipids decreased, but C18:3n3 and C20:5n3 were gradually increased. The levels of longer chain n-3 fatty acids (i.e., C20:5n3 or C22:6n3) in chicks fed a diet containing fish oil (LNO + FO diet) were significantly increased compared to those fed linseed oil with a corresponding level. These results demonstrated that dietary fat enriched with alpha-linolenic acid and longer chain n-3 fatty acids have stronger effects on lowering serum lipid levels than dietary fat composed of either saturated, or n-6 fatty acids, but both n-3 fatty acids sources show differing effects on the deposition of longer chain n-3 fatty acids into tissue lipids.

Animals↗

PubMed1997

Up-regulated expression of angiotensin II type 1 receptor gene in human pathologic hearts.

BACKGROUND: An accumulation of evidence suggests that the local renin-angiotensin system plays a role in the development of cardiac hypertrophy in vivo; however, it remains unknown how the expression of angiotensin II type 1 receptor (AT1), which mediates most of the cardiovascular effects of angiotensin II, is regulated in the left ventricles of human pathologic hearts. METHODS AND RESULTS: Expression of AT1 gene in the left ventricle wall of 14 autopsied human hearts was examined by reverse transcription polymerase chain reaction. The levels of AT1 messenger RNA relative to those of beta-actin messenger RNA in the left ventricle wall were increased 3.8-fold in the hearts with dilated cardiomyopathy (n = 4, P < .05) and 6.2-fold in the noninfarcted areas of hearts with old myocardial infarction (n = 4, P < .05), compared with the control hearts without any cardiac disease (n = 6). The increases in the relative AT1 messenger RNA level showed a positive correlation with myocyte diameter in the adjacent tissue (r = .927, P < .001 for dilated cardiomyopathy and r = .934, P < .005 for old myocardial infarctions) and with the extent of fibrosis (r = .880, P < .005 for dilated cardiomyopathy and r = .690, P < .05 for old myocardial infarction). CONCLUSIONS: Expression of AT1 in these human pathologic hearts was associated with myocardial cell hypertrophy and extent of fibrosis, a finding that further emphasizes the importance of the local renin-angiotensin system in the remodeling of human hearts with dilated cardiomyopathy and old myocardial infarction.

Adolescent↗

PubMed1997

In vivo anti-tumour effect of 3'-sulphonoquinovosyl 1'-monoacylglyceride isolated from sea urchin (Strongylocentrotus intermedius) intestine.

Extracts from sea urchin intestine were screened for new anti-tumour drugs. Four glycolipids, 3'-sulphonoquinovosyl-1', 2'-diacylglyceride (A-4), 3'-sulphonoquinovosyl-1'-monoacylglyceride (2'-lyso A-4, A-5), NeuGc(alpha)2-6Glc(beta)1-1ceramide (A-6) and HSO3-8NeuGc(alpha)2-6Glc(beta)1-1ceramide (A-7), were isolated from the intestine of sea urchin, Strongylocentrotus intermedius, and characterized by means of proton nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. When tested for cytotoxic activity against tumour cells in vitro, A-5 showed significant activity, but A-4, -6 and -7 did not. In addition, the hydrophilic derivatives of A-4 or -5 had no cytotoxicity. Furthermore, the anti-tumour effects on nude mice bearing solid tumours of a human lung adenocarcinoma cell line A-549 were evaluated in vivo using A-4 and -5. As a result, A-5 was found to be significantly effective in suppressing the growth of solid tumours, whereas A-4 had no effect. Pathologically, the solid tumours showed haemorrhagic necrosis areas after treatment with A-5. In this study, we have demonstrated the anti-tumour effect of sulphonoquinovosyl-lysoglyceride (A-5), which provides important information that this sulpholipid could be a useful drug for cancer chemotherapy.

Adenocarcinoma↗

PubMed1997

Dietary safflower phospholipid reduces liver lipids in laying hens.

This experiment was conducted to determine the effects of dietary safflower phospholipids (crude safflower phospholipid and purified safflower phospholipid) on performance and lipid metabolism of laying hens. Sixty-week-old Single Comb White Leghorn laying hens were divided into four groups of seven birds each, and were given one of four experimental diets containing 5% beef tallow (served as a control, tallow), a mixture of safflower oil and palm oil (SP-oil), crude safflower phospholipid (Saf-PLcrude), or purified safflower phospholipid (Saf-PL) for 7 wk. Egg production ratio and daily egg mass were significantly higher in hens fed Saf-PLcrude diets than in hens of the other diet groups. There were no significant differences in egg weight among groups. Liver cholesterol and triglyceride contents were significantly decreased in all treated groups as compared with the control. The activity of hepatic 3-hydroxy-3 methylglutaryl coenzyme A reductase was the highest in hens fed the Saf-PLcrude diet. Serum esterified cholesterol concentration was decreased by feeding of SP-oil, Saf-PLcrude, or Saf-PL diets. Serum lecithin-cholesterol acyltransferase activity was highest in hens fed the tallow diet. Excreta neutral steroid excretion was significantly increased in the Saf-PLcrude or Saf-PL diet groups, although acidic steroid excretion was not affected by dietary treatments. Total cholesterol, triglyceride, and phospholipid contents in egg yolks were not different for any dietary treatments. The fatty acid compositions of egg yolks from hens fed Saf-PLcrude diets were not different with those fed the SP-oil diet, although eggs of hens fed the Saf-PL diet showed lower total polyunsaturated fatty acids. These results suggest that dietary safflower phospholipids may be a valuable ingredient to layers for reducing liver triglycerides and serum cholesterol without any adverse effects.

Animals↗

PubMed1997

Effect of oxygen concentration and free radicals on in vitro development of in vitro-produced bovine embryos.

The effects of free radicals and hypotaurine on the development of bovine embryos produced by in vitro fertilization of in vitro-matured oocytes were examined. Embryos that developed to the 4- to 6-cell stage after in vitro fertilization were cultured without feeder cells in TCM199 medium supplemented with 1% calf serum (CS) under either 5% CO2 in air or 5% O2, 5% CO2 and 90% N2. The percentages of blastocysts (including early, expanding, and hatched stages) that developed under 5% O2 was higher (P < .01) than the percentage of those that developed under 20% O2. The respective percentages in 5% vs 20% O2 concentration were as follows: blastocysts (d 8), 49% vs 17%; expanded blastocysts (d 8), 19% vs 6%; hatched blastocysts (d 10), 16% vs 0%. The development of embryos to blastocysts was suppressed (P < .05) when oxygen radicals were generated in culture medium by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) under both 5% and 20% O2. The addition of hypotaurine permitted the development of embryos to blastocyst stage in medium with AAPH only under 5% O2 (P < .05), but superoxide dismutase (SOD) did not permit the development of embryos to blastocysts. Alternatively, when embryos were cultured in medium without AAPH, the rates of development into blastocysts under 20% O2 increased (P < .05) by the addition of hypotaurine and SOD. However, under 5% O2, the rates of blastocyst formation were not improved by addition of hypotaurine and SOD. Moreover, the cell numbers of blastocysts cultured in medium containing hypotaurine were greater (P < .01) than those of blastocysts cultured in medium without hypotaurine. It is concluded that hypotaurine may exert beneficial effects on in vitro development of bovine embryos under both 20% O2 and 5% O2 of gaseous conditions.

Amidines↗

PubMed1997

Estimation of age from teeth by amino acid racemization: influence of fixative.

To determine the age of a subject from teeth accurately utilizing the racemization rates of amino acids, standard samples of the same tooth species from the same jaw are necessary as controls, as well as data for identification. However, standard teeth are generally stored in fixatives such as ethanol and formalin. We investigated and compared the degree of progression of racemization of dentinal aspartic acid in teeth stored in 95% ethanol, 10% formalin, or 10% neutral formalin fixatives. The racemization rate of dentinal aspartic acid in teeth stored in 10% neutral formalin was the highest, followed by that for teeth stored in 10% formalin then that for teeth stored in 95% ethanol. Teeth stored in these fixatives at 15 degrees C showed almost no progression of racemization. The racemization ratio (D/L ratio) in teeth extracted 10 years previously was almost unchanged from that at the time of extraction, and allowed an accurate evaluation of the subjects age at tooth extraction.

Age Determination by Teeth↗

PubMed1997

Different racemization ratios in dentin from different locations within a tooth.

It has been reported that the amount of D-aspartic acid in dentin is highly correlated with age. However, further studies are necessary to determine the details of this correlation. We quantitatively determined L- and D-aspartic acids in dentin, and from the data calculated the D/L ratio. We did not find any statistically significant difference in the D/L ratio between the same type of left and right teeth from the same jaw, and between the vestibular and lingual sides of the root dentin. However, the D/L ratio was significantly higher on the lingual side than on the labial side of the dentin. Although the D/L ratio in young subjects was comparatively high in the tooth crown and decreased toward the apex of the root, we did not always observe such a tendency in middle- to advanced-age individuals. These results indicate that the ratio of D/L aspartic acid in dentin varies between the lingual side and vestibular side of the crown dentin. Therefore, it appears that the racemization rate of aspartic acid is not uniform but differs with the region of the dentin, and may be affected by differences in factors such as temperature.

Adolescent↗