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Biomedical subjects

T Harada

Publications and source records attributed to T Harada.

At least 667 records · Page 37Linked to original sources
PubMed1992

[Development of an experimental model for spontaneous lymph node metastasis of human esophageal carcinoma in nude mice--histopathological analysis].

Three human squamous cell carcinoma cell lines (HPL-EsC-1-K, -S, and -M) originated from a male patient with esophageal carcinoma were established and were studied on their tumorigenic and metastatic properties in nude mice. All cell lines grew in the hind foot pads following subcutaneous inoculation and produced popliteal lymph node metastasis dose (2-8 x 10(6)/mouse)-dependently. Based on the histopathological findings on serial sections of the lymph nodes, the stages of lymph node invasion by cancer cells were classified into 4 stages (St. 0-III). The time course of lymph node metastasis of EsC-K cells were examined. Advanced stage of metastasis increased according to the time elapsed after tumor cell inoculation. Incidence of metastasis of EsC-K cells were not affected by host factors such as sex differences, anti-asialo GM1 antibody treatment on the hosts. Today, there are few experimental models for studies on spontaneous lymph node metastasis of human carcinomas. This experimental model provides a useful research tool for studies on the biology and therapy for lymph node metastasis of esophageal cancer.

Animals↗
PubMed1992

[Comparative study on nephrotoxicity of ionic and non-ionic contrast agents for drip infused urography].

The effects on renal function of an ionic and hyperosmolaric contrast agent (diatrizoate) and a non-ionic and slightly hypertonic agent (iohexol) for drip infused urography were compared on 60 patients with normal renal function. Urine samples were collected before and 30 minutes after drip infusion of contrast agent, and analyzed for albumin (ALB), gamma-glutamyl transpeptidase (gamma-GTP), N-acetyl-beta-glucosaminidase (NAG), beta 2 microglobulin (beta 2MG) and creatinine (CRE). The urinary excretion of proteins and enzymes was compared with urinary CRE. gamma-GTP, NAG and beta 2MG increased significantly after infusion of diatrizoate. gamma-GTP and beta 2MG increased significantly after infusion of iohexol. Excretion of ALB, gamma-GTP, NAG and beta 2MG was significantly higher after infusion of diatrizoate than after iohexol. The urinary concentration of CRE was significantly lower after infusion of diatrizoate than after iohexol. The degree of renal damage after urography was no related to the appearance of allergy to the contrast agent or age of patient. Therefore, the non-ionic and slightly hyperosmolaric iohexol may be less toxic to the kidneys than the ionic and hypertonic diatrizoate. This nephrotoxicity after drip infused urography is thought to be related mainly to the osmolarity of contrast agent.

Adult↗
PubMed1992

[Effects of glucose ingestion on hepatic hemodynamics in patients with liver disease by per-rectal portal scintigraphy using 99mTcO4- (direct intramural administration of radioisotope method)].

Effects of glucose (225 ml, 300 kcal) ingestion on hepatic hemodynamics was studied in ten patients with liver cirrhosis and eight patients with non cirrhotic liver disease by per-rectal portal scintigraphy using 99mTcO4- (direct intramural administration of radioisotope method). Initial portal blood flow index (IP) and collateral index (CI) were calculated from the time activity curve of heart and liver. The value of IP was not significantly changed between before and after glucose ingestion in cases with liver cirrhosis (before: 0.0160 +/- 0.0016, after: 0.204 +/- 0.106). In cases with non cirrhotic liver disease, the value of IP was significantly increased after glucose ingestion (before: 0.0381 +/- 0.0145, after: 0.0544 +/- 0.0194, p less than 0.02). These findings suggested increase in portal blood flow via inferior mesenteric vein to the cardiac blood flow. The value of CI before glucose ingestion was significantly increased in cases with liver cirrhosis (0.751 +/- 0.156) compared with that in cases with non cirrhotic liver disease (0.517 +/- 0.122), but no significant difference in values after glucose ingestion was found between these two groups.

Administration, Oral↗
PubMed1992

[Valve replacement in a patient with infective endocarditis and ruptured mycotic cerebral aneurysm].

A 55-year-old man with a mild fever and sweating developed severe headache for the days before admission. Cerebral computed tomography and selected cerebral angiography on the day of admission revealed subarachnoid hemorrhage due to rupture of an aneurysm of a distal branch of the left middle cerebral artery. Detection of vegetation on the aortic valve by two dimensional echocardiography confirmed the diagnosis of infective endocarditis with a ruptured mycotic cerebral aneurysm. Because of rapid growth of the vegetation on the aortic valve and progression of heart failure despite antibiotic therapy, emergency cardiac surgery was performed. To prevent re-rupture of the aneurysm, the aortic valve was replaced with a bioprosthetic valve, and no anticoagulant was administered postoperatively. Repeated cerebral angiography revealed that the aneurysm was becoming progressively smaller during the next 9 months. No cerebrovascular accident occurred postoperatively. We believe that it is safe to treat a ruptured mycotic cerebral aneurysm without involvement of a hematoma mass in the brain conservatively, and that use of a bioprosthetic valve, if valve replacement is mandatory, and avoidance of anticoagulant therapy during the postoperative period are advisable in the treatment of a patient with infective endocarditis and a ruptured cerebral mycotic aneurysm.

Aneurysm, Infected↗
PubMed1992

[Diurnal blood pressure variation and autonomic nervous function].

We studied the relationship between diurnal blood pressure variation (DBPV) and autonomic nervous function in various diseases, such as, diabetes mellitus (DM), Parkinson's disease (PD), Shy-Drager syndrome (SDS) and cerebrovascular disease (CVD). Abnormal DBPV was found in those diseases. We speculated that dysfunction of autonomic nervous system might contribute to the abnormal DBPV in DM, CVD, PD, and SDS. The DBPV relates not only to the autonomic nervous system but also the endocrine system, renal function, mental and physical activity, and biological rhythm. From this viewpoint, there is a limitation in studying DBPV as an autonomic nervous function.

Autonomic Nervous System↗
PubMed1991

Structural studies on sulfated oligosaccharides derived from the carbohydrate-protein linkage region of chondroitin sulfate proteoglycans of whale cartilage.

From the carbohydrate-protein linkage region of whale cartilage proteoglycans, which bear predominantly chondroitin 4-sulfate, one nonsulfated, two monosulfated and one disulfated hexasaccharide alditols were isolated after exhaustive digestions with Actinase E and chondroitinase ABC, and subsequent beta-elimination. Their structures were analyzed by chondroitinase ACII digestion in conjunction with HPLC and by 500-MHz 1H-NMR spectroscopy. The nonsulfated compound (A) had the following conventional structure: delta GlcA(beta 1-3)-GalNAc(beta 1-4)GlcA(beta 1-3)Gal(beta 1-4)Xylol, where GlcA, delta GlcA and GalNAc are glucuronic acid; 4,5-unsaturated glucuronic acid and 2-deoxy-2-N-acetylamino-D-galactose, respectively. The other compounds were sulfated derivatives of compound A. Two monosulfated compounds (B and C) had an ester sulfate on C4 or C6 of the GalNAc residue, respectively and the disulfated compound (D) had two ester sulfate groups, namely, one on C4 of the GalNAc and the other on C4 of the Gal residue substituted by GlcA. The molar ratio of A/B/C/D was 0.21:0.16:0.36:0.27. The compound containing Gal-4-O-sulfate was previously isolated by us in the form of a sulfated glycoserine [delta GlcA(beta 1-3)GalNAc(4-O- sulfate)(beta 1-4)GlcA(beta 1-3)Gal(4-O-sulfate)(beta 1-3)-Gal(beta 1- 4)Xyl beta 1-O-Ser] from the carbohydrate-protein linkage region of rat chondrosarcoma chondroitin-4-sulfate proteoglycans [Sugahara K., Yamashina, I., DeWaard, P., Van Halbeek, H. & Vliegenthart, J.F.G. (1988) J. Biol. Chem. 263, 10,168-10,174]. The discovery of this structure in the carbohydrate-protein linkage region of chondroitin 4-sulfate proteoglycans from nontumorous cartilage indicates that it is not a tumor-associated product but rather a physiological biosynthetic product since it represents a significant proportion. The biological significance of this structure is discussed in relation to glycosaminoglycan biosynthesis.

Animals↗
PubMed1991

Purification and cDNA cloning of rat 6-pyruvoyl-tetrahydropterin synthase.

6-Pyruvoyl-tetrahydropterin synthase, which catalyzes the second step in the biosynthesis of tetrahydrobiopterin, was purified approximately 18,000-fold to apparent homogeneity from rat liver. The molecular mass of the native enzyme was estimated to be 83 kDa by gel filtration. The enzyme showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis corresponding to a molecular mass of 17 kDa. Up to 24 residues of the NH2-terminal sequence were determined by Edman degradation, which released a single amino acid at each step. These results indicate that the enzyme consists of identical subunits. The purified enzyme was digested with lysyl endopeptidase or V8 protease, and 11 peptide fragments were isolated. On the basis of the sequences of these peptides, oligonucleotides were synthesized and used to screen a rat liver cDNA library, and one cDNA clone was isolated. The complete nucleotide sequence of the 1176-base pair cDNA was then determined. The deduced amino acid sequence contained 144 amino acid residues, but a NH2-terminal four-amino acid sequence was not found in the purified protein. Therefore, the mature protein consists of 140 amino acids. A single mRNA band of 1.3 kilobases was obtained by RNA blot analysis of rat liver. The predicted amino acid sequence of 6-pyruvoyl-tetrahydropterin synthase was compared with the Protein Sequence Database of the National Biomedical Research Foundation, revealing significant local similarity to large T antigens from the polyomavirus family.

Alcohol Oxidoreductases↗
PubMed1991

Effect of 17 beta-estradiol on the growth of an estrogen receptor-positive human esophageal carcinoma cell line.

Receptors for estrogen and for androgen in the nucleus and cytosol (ERn, ERc, ARn, and ARc, respectively) were studied on two newly established human esophageal carcinoma cell lines, ES-25C and ES-8C. ES-25C was ERn+ (the binding content 4.0 fmol/mg protein, Kd 0.09 nM), ERc-, ARn-, and ARc-. No receptors were found in ES-8C. Various doses of 17 beta-estradiol (E2) were added in vitro to investigate its effect on the growth of these cell lines. No effect of E2 was observed on ER--ES-8C cell line. The growth of ES-25C cell was significantly inhibited at the doses of 10(-10) and 10(-12) mol/l E2 compared with the control. The doubling time of 10(-12) mol/l E2-treated cells was 32 hours whereas that of control was 20 hours. This slower growth was reflected in the deduction of cells in S-phase utilizing 5-bromo 2'-deoxyuridine (BrdU) labeling. The current results strongly suggest that the growth inhibition of ER+ esophageal cancer cell by E2 is mediated by signal transduction induced by the estrogen-estrogen receptor system.

Aged↗
PubMed1991

Distribution and characterization of dihydrodiol dehydrogenases in mammalian ocular tissues.

The immunological relationship of two forms of dihydrodiol dehydrogenase (DD) in pig lens to pig muscle aldose reductase and kidney aldehyde reductase has been studied. Although the minor enzyme form, a monomer of Mr 35,000, was identical with aldose reductase, the major enzyme form, a dimer of Mr 65,000, was distinct from the two reductases. The two enzyme species, although their amounts were low, were distributed in the cornea, iris-ciliary body, retina and choroid of the pig eye. In other mammals, rabbit lens exhibited much higher DD activity than did lens of mice, rats, cats, hamsters, guinea pigs and monkeys, and contained large amounts of the Mr-65,000 enzyme form as well as the minor enzyme form of Mr 35,000. In contrast, only the Mr-35,000 form of the enzyme was found in the lens of other species, except that a small amount of the high-Mr enzyme was detected in mouse lens. The high-Mr enzyme, purified from rabbit lens, was functionally and immunologically similar to dimeric DD of pig lens. The low-Mr enzyme forms, isolated or partially purified from these animal lenses, showed several features in common with aldose reductases from mammalian tissues. The dimeric enzymes of pig and rabbit lenses were NADP(+)-specific, whereas the low-Mr enzymes exhibited dual cofactor specificity and their activities with NAD+ were more than 3-fold higher than those with NADP+.

Alcohol Oxidoreductases↗
PubMed1991

Cloning and sequencing of cDNA encoding rat GTP cyclohydrolase I. The first enzyme of the tetrahydrobiopterin biosynthetic pathway.

A full-length cDNA clone for GTP cyclohydrolase I, the first enzyme of the tetrahydrobiopterin biosynthetic pathway, was isolated and characterized. Synthetic oligonucleotides, constructed according to selected amino acid sequences of purified GTP cyclohydrolase I, were used to screen a rat liver cDNA library. Four clones were isolated, and the length of the longest cDNA insert was 1024 base pairs. The identity of the cDNA was confirmed by amino acid sequence data for eight fragments obtained by lysyl endopeptidase digestion of the purified protein. The coding region encoded a protein of 241 amino acid residues, but the NH2 terminus of the protein contained 11 additional amino acid residues not present in the purified protein. RNA blot analysis showed a single mRNA species of 1.2 kilobases in rat liver. A characteristic feature of the deduced amino acid sequence of GTP cyclohydrolase I was the presence of sequences similar to those proposed for the phosphorylation sites for casein kinase II and growth-associated histone H1 kinase. Furthermore, significant similarity was found to the highly conserved sequences of dihydrofolate reductases, which are known to be involved in the binding of the pterin group of dihydrofolate to the reductases. This region in GTP cyclohydrolase I may be assigned to the binding site of tetrahydrobiopterin, one of the inhibitors of this enzyme.

Amino Acid Sequence↗
PubMed1991

Genomic organization and sequence analysis of the cytochrome oxidase subunit II gene from normal and male-sterile mitochondria in sugar beet.

We have cloned and sequenced the cytochrome oxidase subunit II (coxII) gene from both normal and cytoplasmic male-sterile (CMS) sugar beet. The normal coxII (designated NcoxII) locus was found to be located 1491 bp upstream from the gene for cytochrome oxidase subunit I (coxI) on the same DNA strand and to have a 1463 bp intron which split the coding sequence into two exons (382 and 398 bp). The COXII protein contains 260 amino acid residues. We have also found two copies of the coxII gene (ScoxII-1 and ScoxII-2) to be present in the CMS genome. Our results suggest that the NcoxII gene diverges completely from the ScoxII-1 and ScoxII-2 genes 50 bp 5' to the ATG start codon. In addition, the ScoxII-1 and ScoxII-2 sequences could be readily discriminated from each other by the 3' end and the immediately adjacent flanking sequences of the gene: the 3' divergence results in a 101 codon extension of the ScoxII-2 ORF. Northern blot analysis demonstrates that the coxII gene exhibits altered transcript patterns in CMS compared with normal sugar beet. Different genomic arrangements of the coxII gene are considered to be the result of extensive intra- and inter-molecular recombination events involving the repeated DNA elements in the mitochondrial genome.

Amino Acid Sequence↗
PubMed1991

Treatment of an antenatally diagnosed fetal ovarian cyst by needle aspiration during the neonatal period.

An ultrasound scan revealed an ovarian cyst in the fetal lower abdomen at 29 weeks of gestation. Repeated examinations demonstrated that the cyst increased in size to 6.5 cm x 6.1 cm x 5.0 cm at 33 weeks of gestation, and the cyst showed no complications between 29 weeks of gestation and early infancy. The female infant was vaginally delivered at 41 weeks of gestation without any complications. Transabdominal needle aspiration of the cyst fluid was performed on the 14th day after birth. The concentrations of estrone, estradiol, estriol, and progesterone in the cyst fluid were almost the same as those in the infant's serum, while the concentration of pregnenolone was six times that in the infant's serum. Cytology of the cyst fluid was negative. The cyst thus seems to have been a non-functioning simple cyst of ovarian origin. Follow-up until the baby was one year old showed no recurrence of the cyst.

Adult↗
PubMed1991

Toxicity of gentamicin in organ culture of fetal rat intestine.

The effect of gentamicin in the culture of fetal rat intestine was studied. Fetal rat intestine was cultured with gentamicin or kanamycin at the concentration between 4 to 200 micrograms/ml. Kanamycin did not have influence on lactase, maltase and ALP activities. On the other hand, gentamicin caused decrease of lactase and ALP activities at the concentration of 40 and 200 micrograms/ml compared with the activities at 4 micrograms/ml. Maltase activities did not decrease with gentamicin. Our data suggest that gentamicin could affect lactase and ALP activities and lower concentration should be used in the culture.

Alkaline Phosphatase↗
PubMed1991

The role of platelets in the development of cerebral vasospasm.

A possible role of platelet-derived 5-HT was examined concerning the pathogenesis of cerebral vasospasm. Intracisternal injection of 5 ml of platelet-rich plasma (PRP; approximately 7.5 x 10(8) platelets) induced not only acute (1 h) but also chronic (7 days) angiographically evident cerebral vasospasm in dogs. Sympathetic perivascular nerves on cerebral arteries showed no remarkable change following repeated injections of PRP, as the dense distribution of catecholamine-fluorescence and neuropeptide Y-like immunoreactive nerve fibers on Day 7 was comparable to findings in the preinjection controls. While there were no 5-HT-immunoreactive fibers in the cerebral arteries of control animals, numerous 5-HT-immunoreactive fibers were present in the PRP-injected animals. These results suggest that 5-HT, presumably released from extravasated platelets, may be taken up by nerve endings and act as a vasoconstrictor transmitter in the pathogenesis of chronic vasospasm.

Acute Disease↗