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Biomedical subjects

M Takeuchi

Publications and source records attributed to M Takeuchi.

At least 181 records · Page 10Linked to original sources
PubMed1998

Involvement of Fas in the apoptosis of mouse germ cells induced by experimental cryptorchidism.

The role of Fas in the apoptosis of testicular germ cells was investigated in BALB/c mice and Fas-deficient lpr/lpr mice. Spontaneous apoptosis of germ cells was observed in the testes of 40-day-old BALB/c mice, and experimentally induced cryptorchidism increased this apoptosis to such an extent that there was a decrease in the weight of the testis. Flow cytometry and immunohistochemistry using a Fas-specific monoclonal antibody demonstrated expression of Fas on germ cells including spermatogonia, spermatocytes, and spermatids. Furthermore, analysis by flow cytometry suggested that Fas expression on germ cells was increased following cryptorchidism. However, spontaneous and cryptorchidism-induced apoptosis of germ cells were also observed in 40-day-old Fas-deficient lpr/lpr mice. Moreover, testis weight also decreased following cryptorchidism in the mutant mice. The present results may indicate that the expression of Fas on germ cells does not correlate with spontaneous apoptosis or apoptosis induced by cryptorchidism. However, on the contrary, this study shows that Fas are partly involved in cryptorchidism-induced apoptosis, because the decrease in testis weight of lpr/lpr mice was less than that in BALB/c mice.

Animals↗
PubMed1998

Construction of a low-serine-type-carboxypeptidase-producing mutant of Aspergillus oryzae by the expression of antisense RNA and its use as a host for heterologous protein secretion.

Using an antisense control strategy, we isolated an Aspergillus oryzae mutant that produced low levels of carboxypeptidases (CPases). The mutant TFC-1 expressed the antisense RNA of the structural gene of CPase O and showed about 30% of the CPase activity in the parent strain. Gel filtration analysis indicated that this mutant decreased the CPase activities not only of CPase O but also of CPase O-1 and O-2. This result indicated that the antisense RNA was able to control the expression of the CPase genes as a group. Using the mutant as a heterologous protein expression host that produced the low levels of CPases, a stable and higher level of lysozyme expression could be obtained compared with the wild-type. In vitro proteolytic degradation assay also demonstrated that human lysozyme was degraded by purified CPase O.

Aspergillus oryzae↗
PubMed1998

Action of serine carboxypeptidase from paecilomyces carneus on oligopeptides containing carboxy-terminally amidated peptides

Paecilomyces carneus carboxypeptidase sequentially liberated amino acids from the carboxy-terminus of neurotensin, angiotensin I, bradykinin, and delta sleep-inducing peptide, indicating that the sequential hydrolysis of peptides was limited by the occurrence of intermediates with the structure of -Gly-X (X = L-amino acid), -Pro-X, -X-Gly, and -X-Pro. The enzyme had carboxyamidase and/or amidase activities for the carboxy-terminally amidated peptides. The enzyme essentially acted as a carboxyamidase for the long carboxy-terminally amidated peptides; an amidase became dominant for the substrates in the presence of bulky amino acids such as Arg, Met, Leu, and Phe in the penultimate (P1) and P2 positions, corresponding with the S1 and S2 sites of the enzyme, and the P3 position of carboxy-terminally amidated peptides played a significant role in the action as a carboxyamidase or a amidase.

Journal Article↗
PubMed1998

Apoptosis of photoreceptor cells in ornithine-induced retinopathy.

BACKGROUND: The intravitreal injection of ornithine produces selective damage to the retinal pigment epithelium (RPE) and results in a loss of RPE, choriocapillaris and photoreceptor cells. To elucidate the mechanism of secondary retinal atrophy, we investigated the presence of apoptotic cells in a rat model of ornithine-induced retinopathy. METHODS: At 6 and 12 h and 1, 2, 4, 7, 14 and 28 days after an intravitreal injection of L-ornithine hydrochloride in rat eyes, we removed the eyes and subjected them to histopathological examination. We detected apoptotic cells by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick end labeling (TUNEL) assay, which stains the 3'-OH ends of fragmented DNA. We used electron microscopy to detect the apoptotic cells morphologically. RESULTS: RPE cells were selectively damaged immediately after ornithine administration. TUNEL-positive photoreceptor cells appeared exclusively in the photoreceptor cell layer 12 h after ornithine administration. The number of TUNEL-positive cells increased throughout the 2 days following the injection, then decreased markedly. TUNEL-positive cells remained until 28 days, when the photoreceptor cells had disappeared. The ganglion cell layer, inner nuclear layer and damaged RPE cells were negative for TUNEL staining during all stages. The electron microscopic study also revealed the pyknotic nuclei of apoptotic photoreceptor cells. CONCLUSION: An intravitreal injection of ornithine caused primary damage to the RPE, and subsequently some of the photoreceptor cells revealed apoptosis by TUNEL assay. These findings suggest the dysfunction of the RPE causes photoreceptor cell death according to the intrinsic program of an apoptotic mechanism.

Animals↗
PubMed1998

Sustained induction of hepatocyte growth factor by sensitization with freeze-thawed hepatic tissue.

Hepatocyte growth factor (HGF) is a mitogen for hepatocytes, and has therapeutic potential for fibrotic/cirrhotic liver. Therefore, the induction of HGF in vivo is considered to be useful in the treatment of liver dysfunction caused by cirrhosis, chronic hepatitis, or extensive surgical resection. In this study, we examined the sustained induction of HGF by inoculation of freeze-thawed hepatic tissue (FTHT). Serum from rats inoculated with FTHT increased [3H]thymidine incorporation i.e., increased DNA synthesis, in primary cultured rat hepatocytes. The DNA synthesis was significantly promoted by the addition of the FTHT-sensitized serum, while this DNA synthesis was inhibited by neutralizing anti-rat HGF antibody. The concentration of HGF in the FTHT-sensitized serum was increased by day 3 after the inoculation. The time of HGF induction was dependent on the inoculated volume of FTHT, but peaks of HGF concentration were found on day 5 with different volumes of FTHT. Injurins, inducers of HGF, were also induced in the FTHT-sensitized rats, with their peak levels on day 3. The FTHT inoculated tissue showed inflammatory cell infiltration, which was gradually absorbed, and had completely disappeared by day 14 after the inoculation. Although mild inflammatory cell infiltration was observed in non-freeze-thawed inoculated hepatic tissue (NFHT) a tight capsule formed around the NFHT, and was scarcely phagocytized on day 14. These results suggest that FTHT inoculation induces HGF sustainedly through the increased synthesis of injurins, and that freeze-thawed tissue, which is easily phagocytized, is important for the sustained induction of HGF.

Animals↗
PubMed1998

Synovial sarcoma of the esophagus: report of a case.

Synovial sarcomas are exceedingly rare neoplasms of the digestive tract. We herein report a case of a synovial sarcoma occurring in the esophagus of a 20-year-old man. He had a history of acute lymphocytic leukemia and had undergone aggressive chemotherapy between the ages of 4 and 8 years. The tumor, which was large and extended into the upper mediastinum, was successfully resected without an esophagectomy via the cervical approach. After postoperative radiation and chemotherapy, the patient remained healthy, without any evidence of disease 20 months after the operation.

Adult↗
PubMed1998

Safety and optimal dose of intracoronary adenosine 5'-triphosphate for the measurement of coronary flow reserve.

BACKGROUND: Adenosine 5'-triphosphate (ATP) has been demonstrated to have similar vasodilator potency and fewer hemodynamic or electrocardiographic derangements compared with papaverine in the measurement of coronary flow reserve. However, there is little data about its optimal dose and the effect on myocardial lactate metabolism. METHODS: Under continuous monitoring of the left anterior descending coronary flow velocity with a Doppler guide wire, we investigated the changes of hemodynamics, electrocardiogram, and myocardial lactate metabolism before and after the administration of 50 microg ATP and 10 mg papaverine into the left coronary artery in 18 patients with normal coronary arteries. To determine the optimal dose of ATP for the coronary flow reserve in the left coronary artery, we measured coronary flow velocity with five incremental doses of intracoronary ATP (0.5, 5, 15, 30, and 50 microg) and 10 mg of papaverine in another seven patients. RESULTS: In contrast to papaverine, ATP did not produce any significant changes in hemodynamics or the electrocardiogram. The increase in the coronary flow velocity of the two agents was similar. Although all patients showed lactate production after the administration of papaverine, only three patients showed lactate production after ATP (p < 0.001). The coronary flow reserve derived from > or = 215 microg of ATP was similar to that derived from papaverine. There was a significant correlation between the coronary flow reserve obtained with > or = 5 microg of ATP and that obtained with papaverine. CONCLUSIONS: These results suggest that maximal coronary vasodilation in the left coronary artery can be safely obtained with doses > or = 15 microg of intracoronary ATP in patients with normal coronary arteries.

Adenosine Triphosphate↗
PubMed1998

Structure of the erythrocyte membrane skeleton as observed by atomic force microscopy.

The structure of the membrane skeleton on the cytoplasmic surface of the erythrocyte plasma membrane was observed in dried human erythrocyte ghosts by atomic force microscopy (AFM), taking advantage of its high sensitivity to small height variations in surfaces. The majority of the membrane skeleton can be imaged, even on the extracellular surface of the membrane. Various fixation and drying methods were examined for preparation of ghost membrane samples for AFM observation, and it was found that freeze-drying (freezing by rapid immersion in a cryogen) of unfixed specimens was a fast and simple way to obtain consistently good results for observation without removing the membrane or extending the membrane skeleton. Observation of the membrane skeleton at the external surface of the cell was possible mainly because the bilayer portion of the membrane sank into the cell during the drying process. The average mesh size of the spectrin network observed at the extracellular and cytoplasmic surfaces of the plasma membrane was 4800 and 3000 nm2, respectively, which indicates that spectrin forms a three-dimensionally folded meshwork, and that 80% of spectrin can be observed at the extracellular surface of the plasma membrane.

Cell Fractionation↗
PubMed1998

Development of approximate formula for LDL-chol, LDL-apo B and LDL-chol/LDL-apo B as indices of hyperapobetalipoproteinemia and small dense LDL.

Estimation of LDL-chol and LDL-apo B is useful for the diagnosis of hyperapobetalipoproteinemia (normal LDL-chol with increased LDL-apo B), which is one of the most commonly occurring lipoprotein disorders associated with atherosclerotic cardiovascular diseases. The LDL-chol/LDL-apo B ratio reflects the level of small dense LDL, which is an important risk factor for IHD, CVD and ASO. In order to estimate LDL-apo B and LDL-chol/LDL-apo B ratio from blood chol, TG, HDL-chol and apo B values, we developed a formula for LDL-chol ¿0.94Chol- 0.94HDL-chol - 0.19TG¿, LDL-apo B ¿apo B - 0.09Chol + 0.09HDL-chol-0.08TG¿, and LDL-chol/LDL-apo B [¿0.94Chol-0.94HDL-chol - 0.19TG¿/¿apo B - 0.09Chol + 0.09HDL-chol-0.08TG¿] using ultracentrifugal data from 2179 subjects. These were calculated by the least squares method on the assumption that a certain compositional relationship exists between Chol, TG and apo B in VLDL, IDL and LDL. Friedewald's formula for LDL-chol (Chol - HDL-chol - 0.2TG) includes IDL-chol, but the present new formula theoretically excludes IDL-chol. It suggests a better estimation for the correct LDL-chol. Estimated LDL-apo B is useful for the diagnosis of hyperapobetalipoproteinemia and detection of small dense LDL. Without performing ultracentrifuge, additional information is obtained for the quantitative and qualitative alteration of LDL, such as small dense LDL. The above formulae and a new classification of lipoproteinemia including apo B were applied to the analyses of lipoprotein profiles of subjects with cardiovascular diseases, which were compared with those in the general population. Hyperapobetalipoproteinemia with high TG was observed 2-3 times more frequently in subjects with CAD, MI and ASO than in the Suita population. Lower ratios of LDL-chol/LDL-apo B, reflecting preponderance of small dense LDL, were observed in the above three groups. Type IIb and combined low HDL-chol were also frequent phenotypes in CAD, A-Th and ASO. The present formulae are useful for the detailed analyses of lipoprotein disorders in both qualitative as well as quantitative aspects.

Apolipoproteins B↗
PubMed1998

High-turnover osteopenia in preterm infants: determination of urinary pyridinium cross-links of collagen.

Osteopenia is a frequent condition in preterm infants, but its pathogenesis is uncertain. In the present study, we measured longitudinal changes in the excretion of pyridinium cross-links of collagen (specific markers of bone resorption) and evaluated the relationship between collagen cross-links and other indexes of bone and renal function in preterm infants. In these infants, urinary collagen cross-links were markedly increased on day 7 and day 30 of life and at estimated full-term gestation. The values were several times higher than those of older children and almost comparable to those of healthy full-term infants. Cross-link excretion did not correlate with beta2-microglobulin (B2M) or N-acetyl-beta-D-glucosaminidase (NAG) activity (markers of renal function), indicating that cross-link excretion is not influenced directly by infantile renal function. High serum osteocalcin and low bone mineral density (BMD) in the lumbar spine were also observed at estimated full-term gestation. There was no significant correlation between collagen cross-link excretion and either serum osteocalcin or spine BMD. We conclude that a state of high bone turnover underlies the development of osteopenia in preterm infants.

Aging↗
PubMed1998

Specific fluorescence assay for advanced glycation end products in blood and urine of diabetic patients.

Late rearrangement products that accumulate by glycation of proteins, known as advanced glycation end products (AGEs), have been implicated in the pathogenesis of complications related to diabetes. Circulating AGEs, especially in the form of a small peptide (AGE-peptide) of less than 10 kd, increase in the blood of diabetic patients with end-stage renal disease (ESRD). The aim of the study was to evaluate AGE-peptide levels by measuring AGE-specific fluorescence (excitation at 370 nm and emission at 440 nm) and to examine the relationship between AGE-peptide and diabetic nephropathy. AGE-specific fluorescence in serum and urine were examined in diabetic subjects with various levels of renal complications of varying severity: normoalbuminuria (N), microalbuminuria (Mi), macroalbuminuria (Ma), chronic renal failure (C), and hemodialysis (HD). We also assessed correlations among the AGE-peptide level and age, duration of diabetes, hemoglobin A1c (HbA1c), serum creatinine, and creatinine clearance. Serum and urine AGE-peptide levels in C and HD were significantly higher than in N, Mi, and Ma. Serum AGE-peptide levels were significantly correlated with serum creatinine (r=.866, P < .0001) and creatinine clearance (r=-.720, P < .0001) but not with duration of diabetes or age. There was a significant correlation between AGE-peptide levels measured by enzyme-linked immunosorbent assay (ELISA) and levels determined from the specific fluorescence intensity (r=.688, P < .0001). These findings suggest that renal function may play a greater role in the accumulation of AGEs than persistent hyperglycemia in diabetic patients. Measurement of AGE-specific fluorescence (ie, AGE-peptide) may serve as a simple and useful test to assess circulating AGE levels and monitor AGE excretion.

Creatinine↗
PubMed1998

HVJ-liposome mediated gene transfer into hepatocytes in vivo.

BACKGROUND/AIMS: The efficient transduction of appropriate target cells will be critical for gene therapy. We evaluated the suitability of hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer for gene therapy of liver diseases. METHODS: The Escherichia coli beta-galactosidase (beta-gal) gene was introduced into rat liver by HVJ-liposome to examine gene transfer efficacy and persistence of expression with or without partial hepatectomy prior to transfection. RESULTS: About 30% of hepatocytes were transduced after portal vein injection. Gene expression was transient, with only 2% of hepatocytes expressing beta-gal after 4 weeks. However, partial hepatectomy performed 24 h prior to injection resulted in persistently high levels of beta-gal for 4 weeks after injection. A 247-bp beta-gal polymerase chain reaction fragment transcript was detected in livers of transfected rats, but not in livers of control rats. The rat livers following gene transfer were histologically normal, and serum glutamic-pyruvic transaminase was not found to be elevated in rats. CONCLUSIONS: Our results demonstrate that HVJ-liposome-mediated gene transfer produced high gene transduction and persistent gene expression in the liver.

Alanine Transaminase↗
PubMed1998

Insertion/deletion polymorphism in intron 16 of the ACE gene and left ventricular hypertrophy in patients with end-stage renal disease.

We studied the relationship between polymorphism in intron 16 of the angiotensin-converting enzyme (ACE) gene and left ventricular (LV) hypertrophy in uremic patients treated with hemodialysis therapy. The LV parameters were not different for age-, hematocrit-, and blood pressure-matched patients in DD, ID, and II genotype groups. The most important factor for LV hypertrophy was systolic blood pressure, which correlated with the posterior wall thickness (r=0.35; P=0.001) and LV mass index (LVMI; r=0.23; P=0.032). Among nonhypertensive patients, the frequency of interventricular septum (IVS) hypertrophy (>12 mm) and hypertrophy in LVMI (>145 g/m2) was significantly greater in patients with the DD genotype than in I allele-positive (+) patients. The odds rate for IVS hypertrophy was 5.04 (95% confidence interval, 1.15 to 24.8). These data suggest that the DD genotype of the ACE gene polymorphism is a contributory factor for the development of LV hypertrophy in patients with end-stage renal disease (ESRD).

Age Factors↗
PubMed1998

The effect of early burn wound excision on regional gastric blood flow in rats.

This study examined the effects of early burn wound excision on gastric blood flow and on morphologic changes in mucosal vessels. Wistar rats were given a 30% total body surface area burn and divided into four groups, consisting of control animals (group 1), animals with burn injury without and with fluid resuscitation (groups 2 and 3, respectively), and animals with both fluid resuscitation and early wound excision (group 4). Gastric mucosal blood flow (GMBF) was measured by the hydrogen gas clearance method up to 24 h post-burn. Morphologic changes in mucosal vessels were examined by scanning electron microscopy (SEM) at 3 and 24 h post-burn. The GMBF sharply decreased in the acute period after the burn. In group 4, however, it recovered to the initial value by 6 h post-burn and there was no significant change throughout the experiment. Morphologically, although the mucosal capillaries revealed some changes such as irregularity in diameter in groups 2-4 at 3 h, most of mucosal capillaries retained their original appearance in group 4 at 24 h post-burn. These result suggest that early excision does not aggravate the state of gastric ischemia.

Animals↗
PubMed1998

Value of mild hypothermia in patients who have severe circulatory insufficiency even after intra-aortic balloon pump.

STUDY OBJECTIVE: To evaluate the effectiveness of mild hypothermia in postcardiac surgical patients with severe heart failure in spite of conventional medical therapy and the use of intra-aortic balloon pumping (IABP). DESIGN: Prospective, clinical study. SETTING: Teaching hospital. PATIENTS: 10 postcardiac surgical patients with severe heart failure despite the use of IABP with massive doses of catecholamine. INTERVENTIONS: Patients underwent mild hypothermia produced by surface cooling (to approximately 34.5 degrees C). Hemodynamic criteria for the induction of hypothermia included a cardiac index (CI) of less than 2.2 L/min/m2 with a pulmonary capillary wedge pressure (PCWP) of up to 18 mmHg despite the use of IABP with massive doses of catecholamine. MEASUREMENTS AND MAIN RESULTS: After control measurements had been taken at normal core body temperature (37 degrees C), patients were cooled to approximately 34.5 degrees C (using a cooling blanket and gastric lavage with cold water) to decrease tissue oxygen (O2) demand. Patients showed significant improvements in CI (1.9 +/- 0.3 to 2.2 +/- 0.3 L/min/m2), mixed venous O2 saturation, (SvO2; 55 +/- 7 to 64 +/- 6%), and urine output (2.1 +/- 1.1 to 3.4 +/- 2.2 ml/kg/hr). Patients were rewarmed while SvO2 was being monitored. The duration of the hypothermia was 38 +/- 41 hours. Oxygen delivery increased in 8 of the 10 patients, the mean value (+/- SD) for the group rising from 309 +/- 65 ml/min/m2 to 358 +/- 57 ml/min/m2 as temperature was reduced from 36.7 +/- 0.4 degrees C to 34.7 +/- 0.3 degrees C. All patients were successfully weaned from IABP at 140 +/- 107 hours after admission to the intensive care unit. CONCLUSIONS: Mild hypothermia is a simple and useful procedure for improving the circulation of postcardiac surgical patients with severe heart failure despite the use of IABP.

Aged↗
PubMed1998

A novel second isoenzyme of the human UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1,4-N-acetylglucosaminyltransferase family: cDNA cloning, expression, and chromosomal assignment.

We isolated a novel cDNA encoding a second isoenzyme of UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1,4-N-acetylglucosaminyltransferase (GnT-IV; EC 2.4.1.145). The nucleotide and deduced amino acid sequences of the cDNA were homologous to those of the previously cloned human GnT-IV cDNA (63% and 62% identity, respectively). The new cDNA is also confirmed to express GnT-IV activity, suggesting that two isoenzymes of human GnT-IV exist. Although genomic Southern analysis suggested that both genes exist in many mammalian species and the chicken, northern analysis revealed that both genes are expressed in different ways in human tissues. This is the first report concerning the gene family of an N-acetylglucosaminyltransferase in mammals.

Amino Acid Sequence↗