Biomedical subjects

M Yamanaka

Publications and source records attributed to M Yamanaka.

At least 37 records · Page 2Linked to original sources

PubMed2001

Role of the renal kallikrein-kinin system in the development of salt-sensitive hypertension.

The role of the renal kallikrein-kinin system in the development of salt-sensitive hypertension was studied using mutant kininogen-deficient Brown-Norway Katholiek (BN-Ka) rats, which generate no kinin in their urine, and other hypertensive rat models. It was found that ingestion of a low sodium diet or infusion of NaCl in doses slightly above 0.15 M caused hypertension and sodium accumulation in erythrocytes and the cerebrospinal fluid of kininogen-deficient BN-Ka rats. Development of hypertension in the deoxycorticosterone-acetate-salt model was completely prevented by administration of a newly discovered inhibitor, ebelactone B, of carboxypeptidase Y-like exopeptidase (an urinary kininase). The urinary kallikrein excretion of spontaneously hypertensive rats was lower than that of Wistar Kyoto rats at 4 weeks of age and did not increase by administration of furosemide, a diuretic agent, although approximately 50% of the diuretic action of this agent was dependent upon the renal kallikrein-kinin system in normal rats. In conclusion, the renal kallikrein-kinin system works as a safety valve for excess sodium intake.

Animals↗

PubMed2001

Breast cancer presenting with the syndrome of inappropriate secretion of antidiuretic hormone after simple mastectomy.

A 71-year-old woman showed disorientation 7 days after simple mastectomy for right breast cancer. Computed tomography of the brain was normal. The level of serum sodium was very low (110 mEq/l), while the urine sodium level was normal. The osmolality of urine was higher (342 mosmol/kg) than that of serum (220 mosmol/kg). These data suggested a syndrome of inappropriate secretion of antidiuretic hormone. A fluid restriction, infusion of hypertonic saline and administration of diuretics gradually increased the level of serum sodium. Subsequently, disorientation disappeared. This is a rare case of the syndrome of inappropriate secretion of antidiuretic hormone caused by simple mastectomy, a relatively minor surgical procedure.

Aged↗

PubMed2001

Mazindol administration improved hyperphagia after surgery for craniopharyngioma--case report.

A 54-year-old man presented with visual disturbance and polydipsia. Magnetic resonance imaging disclosed a cystic mass which extended from the intrasellar to the suprasellar region. Bifrontal craniotomy was performed and the tumor was totally removed. Histological findings confirmed the diagnosis of craniopharyngioma. Postoperatively, the patient suffered from transient disorientation. About one month after the operation the patient manifested hyperphagia and he gained 15 kg in one month. Mazindol, a non-amphetaminergic anorectic agent, was administered for 3 weeks. His appetite normalized and his weight fell and stabilized even after mazindol administration was ceased.

Appetite Depressants↗

PubMed2001

Analysis of the gene expression of SPARC and its prognostic value for bladder cancer.

PURPOSE: We analyzed the gene expression of the glycoprotein termed secreted protein, acidic and rich in cysteine (SPARC), also called osteonectin and BM40, in bladder cancer and its relationship with conventional clinical-histopathological manifestations, evaluated its prognostic value for patient outcome and determined the possible mechanism underlying the effect of SPARC on bladder cancer progression. MATERIALS AND METHODS: Tissue samples from 63 patients with bladder cancer were used for analysis. Gene expression levels of SPARC and matrix metalloproteinase-2 were analyzed using reverse transcription-polymerase chain reaction. Correlations of the expression of SPARC with histopathological findings or patient outcome and with matrix metalloproteinase-2 were evaluated. RESULTS: Significantly higher expression of SPARC was observed in grades 3 and 2 than in grade 1 tumors (p <0.001 and <0.05, respectively). Stage T2 or greater invasive tumors expressed a significantly higher level of SPARC than stages T1 or less superficial tumors (p <0.0001). Patients in whom the lesions showed high SPARC expression had a significantly worse prognosis than those with low SPARC expression disease (p <0.0001). Even in those with invasive bladder cancer high SPARC expression was associated with significantly worse survival than low expression (p <0.01). Moreover, gene expression of SPARC significantly correlated with matrix metalloproteinase-2 gene expression (p <0.0001), implying that regulation of matrix metalloproteinase-2 expression may be a possible mechanism underlying the effect of SPARC on bladder cancer progression. CONCLUSIONS: A significant correlation was detected of the gene expression level of SPARC with histological grade, pathological stage and bladder cancer prognosis. SPARC may have an important role in bladder cancer progression and provide some additional information in patients with bladder cancer.

Aged↗

PubMed2000

Ytterbium(III) triflate/TMSCI: efficient catalyst for imino ene reaction

[reaction: see text] Ytterbium trifluoromethanesulfonate [Yb(OTf)3] catalyzed the imino ene reaction of N-tosyl aldimine with alpha-methylstyrene to give a homoallylamine in moderate yield. Furthermore, addition of a catalytic amount of chlorotrimethylsilane (TMSCI) dramatically enhanced the imino ene reaction.

Journal Article↗

PubMed2000

Development of key neurons for learning stimulates learning ability in Lymnaea stagnalis.

The pond snails, Lymnaea stagnalis, change their ability of conditioned taste aversion (CTA) during their development, for example, stage 29 embryos can acquire the CTA, whereas immature snails come to use a long-term memory to maintain the conditioned response. We thus examined the relationships between the learning ability and the development of key neurons (cerebral giant cells: CGCs) for this CTA. The immunoreactivity of serotonin, which is a main neurotransmitter employed in the feeding circuitry, was first observed in the CGCs at the stage 29. After hatching, the CGCs developed their neuropile faster than other cells in the buccal and cerebral ganglia, resulting in their early innervation at the immature stage. The present results, therefore, indicate that the development of key neurons for learning stimulates the developmental changes in learning ability.

Animals↗

PubMed2000

Interference screw fixation of doubled flexor tendon graft in anterior cruciate ligament reconstruction - biomechanical evaluation with cyclic elongation.

OBJECTIVE: To biomechanically evaluate interference screw fixation of the doubled flexor tendon graft in anterior cruciate ligament reconstruction using cyclic elongation. DESIGN: Biomechanical properties of the interference screw fixation of the flexor tendons were compared with those of three standard fixation techniques which had been commonly performed in anterior cruciate ligament reconstruction. BACKGROUND: The interference screw fixation of the flexor tendon graft has attracted notice because of various possible advantages. METHODS: Forty fresh frozen porcine hind limbs were divided into four groups of ten knees each. Anterior cruciate ligament reconstruction was carried out in each group using one of four different procedures. For each group, five femur-graft-tibia complexes underwent submaximal cyclic elongation of 5000 cycles after initial tension of 80 N was applied. Then, tensile testing was performed in the same manner for the complex with a tensile tester. The remaining five complexes were examined in the same tensile test without applying any cyclic elongation. RESULTS: The initial tension was more rapidly relaxed by cyclic elongation in the flexor tendon graft fixed with interference screws than in the bone-patellar tendon-bone graft fixed with two standard techniques. After cyclic elongation, while the ultimate failure load of the former was significantly lower than the latter, the linear stiffness of the former was significantly higher than the flexor tendon graft fixed with sutures. CONCLUSION: The present study has clarified that the advantage of the interference fixation for the doubled flexor tendon graft is the high linear stiffness of the FGT complex, and the disadvantage of this screw is the low ultimate failure load of the FGT complex. RELEVANCE: The present study has suggested that vigorous activities should not be permitted for the patients in the early period after anterior cruciate ligament reconstruction using this fixation technique, because of its low ultimate failure load.

Animals↗

PubMed2000

Hypoxic conditions decrease the mRNA expression of proalpha1(I) and (III) collagens and increase matrix metalloproteinases-1 of dermal fibroblasts in three-dimensional cultures.

The effect of hypoxia on the expression of extracellular matrix-related genes by human dermal fibroblasts was investigated using a novel three-dimensional culture supplemented with L-ascorbic acid 2-phosphate. Experiments were performed by placing replicate dishes in either hypoxic (2%) or in normoxic (20%) condition for various periods of time ranging up to 72 h. The mRNA expression levels of proalpha1(I), proalpha1(III) collagens and MMP-1 were analyzed using Northern blotting. Hypoxia transiently increased proalpha1(I) and proalpha1(III) collagen gene expression at 24 h, but a prolonged exposure to hypoxia decreased them. A slight increase in MMP-1 mRNA was observed at 24 h and prolonged exposure for up 72 h resulted in significantly increased expression of MMP-1 gene. Our results suggest that enhanced degradation as well as decreased synthesis of collagens induced by hypoxia may account for the delayed wound healing associated with circulatory disturbances.

Actins↗

PubMed2000

Combination analysis of genetic alterations and cell proliferation in small intestinal carcinomas.

We analyzed K-ras and p53 mutations, microsatellite instability (MSI), and loss of heterozygosity (LOH) using the polymerase chain reaction (PCR) methods, as well as p53 expression and the Ki-67 labeling index (LI) using immunohistochemistry in 10 duodenal and 10 jejunal/ileal carcinomas. K-ras mutations were detected in two duodenal (20%) and three jejunal/ileal (30%) carcinomas and p53 mutations in one (10%) and three (30%), respectively. LOH of 17p was detected in two duodenal (20%) and two jejunal/ileal (20%) carcinomas and p53 expression in four duodenal (40%) and four jejunal/ileal (40%). One duodenal (10%) and two jejunal/ileal (20%) carcinomas demonstrated MSI. LOH of APC was detected in three jejunal/ileal (30%), but none of the duodenal carcinomas. The Ki-67 LI was 44% in duodenal and 52.6% in jejunal/ileal carcinomas. A subset of small intestinal carcinomas showed involvement of K-ras and p53 mutations, LOH of APC, and MSI. A difference was also apparent for LOH of APC between duodenal and jejunal/ileal carcinomas.

Adult↗

PubMed2000

Biliary excretion of bile acids and organic anions in zone 1- and zone 3-injured rats.

AIMS: Hepatocytes in zone 1 of the hepatic lobule play a role in the uptake and biliary excretion of bile acids and organic anions under physiological conditions, and those in zone 3 may play a role only with a high-dose load. To further elucidate the role of hepatic zonation on the handling of bile acids and organic anions, biliary excretion of these compounds was studied in zone 1- and zone 3-injured rats. METHODS: Biliary excretion of bile acids and organic anions was studied in zone 1- and zone 3-injured rats, caused by allyl alcohol and bromobenzene, respectively. RESULTS: Biliary excretion of a tracer dose of taurocholate was unchanged in the injury in both zones, but that of leukotriene C4 was decreased in zone 1 injury. The excretory maximum of taurocholate was decreased with zone 1 and the zone 3 injuries. Biliary excretion of deoxycholate metabolites was decreased in zone 3 injury, although the profile of metabolites in the bile was unchanged. Sulfobromophthalein excretion was decreased in zone 1 injury, but unchanged in zone 3 injury. CONCLUSIONS: These findings indicate that zone 1 is very important for biliary excretion of both organic anions and bile acids. In contrast, zone 3 is considered not to have a role in biliary excretion of organic anions, but to play a role in the excretion of bile acids.

Alanine Transaminase↗

PubMed2000

Solitary fibrous tumor of the vagina.

The solitary fibrous tumor (SFT) is a rare tumor that most commonly arises in the pleura. Recent evidence has indicated that this tumor originates from mesenchymal, probably fibroblastic, cells and is not restricted to the pleura. However, its occurrence in the female genital tract is extremely rare. We report a case of primary SFT that originated from the vagina in a 34-year-old female. It was a pedunculated polypoid tumor and occurred at the site of scar tissue, caused by laceration during her last labor 7 years previously. Histologically, the tumor was predominantly composed of a random proliferation of spindle cells, intimately admixed with collagen. Immunohistochemically, the cells were strongly positive for CD34, vimentin and bcl-2, but were negative for S-100 protein, neuron-specific enolase, smooth muscle actin, desmin, CD68, cytokeratins and epithelial membrane antigen. To the best of our knowledge, this is the first reported case of a primary vaginal SFT in the English literature. Our report suggests to include SFT in the differential diagnosis of a spindle cell neoplasm originating from the vagina.

Adult↗

PubMed2000

Umbilical cord ulcer: a serious in utero complication of intestinal atresia.

We have experienced six cases of umbilical cord ulcer that resulted in life-threatening antenatal fetal haemorrhage. Fetal distress and bloody amniotic fluid that led to intrauterine and neonatal death in four patients complicated the pregnancy courses. The remaining two infants are still alive. All the infants had upper intestinal atresia below the papilla of Vater. Pathologically, umbilical arteries and surrounding Wharton's jelly were necrotic in all cases. Activated macrophages containing pigment granules were present within the ulcer bed, necrotic areas of Wharton's jelly and fetal membranes. During the same period, we encountered 38 other cases of upper intestinal atresia and the placentae were examined in 23 cases. Microscopic degeneration of Wharton's jelly was seen in three out of 23 cases. Total bile acids content in amniotic fluid was elevated in one case of umbilical cord ulcer. We speculate that the umbilical cord ulcer is closely related to in utero regurgitation of the bile. We also think that the incidence of this serious association is higher than has been reported previously.

Adult↗

PubMed2000

Molecular cloning and characterization of phosphatidylcholine transfer protein-like protein gene expressed in murine haploid germ cells.

We have isolated a cDNA clone specifically expressed in spermiogenesis from a subtracted cDNA library of mouse testis. The cDNA consisted of 1392 nucleotides and had an open reading frame of 873 nucleotides encoding a protein of 291 amino acid residues. Computer-mediated homology search revealed that the nucleotide sequence was unique but the deduced amino acid sequence had similarity to mouse phosphatidylcholine transfer protein (PCTP). We named this newly isolated gene PCTP-like protein. Northern blot analysis revealed a 1.4-kilobase mRNA expressed in the testis, kidney, liver, and intestine with the highest level in the testis. Messenger RNA expression in the testis was detected first on Day 23 in postnatal development and then increased up to adulthood. The protein, having a molecular weight of approximately 40 000, was encoded by the mRNA and was detected at the tail of the elongated spermatids and sperm by immunohistochemical staining.

Aging↗

PubMed2000

Isolation and characterization of a haploid germ cell-specific novel complementary deoxyribonucleic acid; testis-specific homologue of succinyl CoA:3-Oxo acid CoA transferase.

We have isolated a cDNA clone encoding a mouse haploid germ cell-specific protein from a subtracted cDNA library. Sequence analysis of the cDNA revealed high homology with pig and human heart succinyl CoA:3-oxo acid CoA transferase (EC 2.8.3.5), which is a key enzyme for energy metabolism of ketone bodies. The deduced protein consists of 520 amino acid residues, including glutamate 344, known to be the catalytic residue in the active site of pig heart CoA transferase and the expected mitochondrial targeting sequence enriched with Arg, Leu, and Ser in the N-terminal region. Thus, we termed this gene scot-t (testis-specific succinyl CoA:3-oxo acid CoA transferase). Northern blot analysis, in situ hybridization, and Western blot analysis demonstrated a unique expression pattern of the mRNA with rapid translation exclusively in late spermatids. The scot-t protein was detected first in elongated spermatids at step 8 or 9 as faint signals and gradually accumulated during spermiogenesis. It was also detected in the midpiece of spermatozoa by immunohistochemistry. The results suggest that the scot-t protein plays important roles in the energy metabolism of spermatozoa.

Amino Acid Sequence↗

PubMed2000

Effect of hepatocyte growth factor on sperm motility.

PROBLEM: Hepatocyte growth factor (HGF) exists abundantly in seminal plasma and its receptor, c-met, is expressed on spermatozoa. Considering its motogenic activity, we speculated that HGF might affect the movement ability of spermatozoa. METHODS: Recombinant HGF was added to washed spermatozoa and their movements were analyzed using a computer-assisted sperm analyzer. The concentration of HGF in the seminal plasma of infertile patients (n = 83) was measured by ELISA, and the data were compared with their hormonal profile and semen parameters. RESULTS: The HGF physiological concentration (1 ng/mL) maintained the motility of sperm after a long incubation, though the difference was not statistically significant. Recombinant HGF did not affect the linearity or frequency of movement, which suggested that it does not evoke the hyperactivation of spermatozoa. The concentration of HGF in seminal plasma did not correlate with any clinical parameter of the patients. CONCLUSIONS: These findings contradict the theory that HGF controls the movement of sperm. The main role of this axis in the male reproductive system might be maturation in the epididymis.

Hepatocyte Growth Factor↗

PubMed1999

Species-selective analysis by microcolumn multicapillary gas chromatography with inductively coupled plasma mass spectrometric detection.

A glass rod (5-20 cm long, 2 mm o.d.) containing more than 1200 parallel microchannels (< 40 microns i.d.) was converted into a high-resolution (> 100 theoretical plates cm-1) GC column by coating the inside of each channel in a way that compensated for the dispersion of the channel inner diameter. The columns were evaluated for the separation of mixtures of several organometallic (Hg, Sn, Pb) compounds prior to on-line sensitive metalselective detection by ICPMS. Chromatographic separation conditions were optimized to enable a rapid (within a maximum 30 s) multielemental speciation analysis. Absolute detection limits were 0.1 pg for Hg, 0.05 pg for Sn, and 0.03 pg for Pb using the carrier gas flows of approximately 200 mL min-1. The microcolumn multicapillary GC/ICPMS developed was applied to the analysis of a number of environmental samples. The results were validated with certified reference materials for tin (BCR477, PACS-2) and mercury (DORM-1, TORT-1).

Environmental Pollutants↗

PubMed1999

Epstein-Barr virus infection resembling autoimmune hepatitis with lactate dehydrogenase and alkaline phosphatase anomaly.

A 73-year-old man had fever, lymphadenopathy, granulocytopenia, thrombocytopenia, ascites, pleural effusion, liver injury, and an allergic-like skin rash. Autoantibodies, such as anti-nuclear antibody, were shown, and there were lactate dehydrogenase and alkaline phosphatase anomalies and platelet-associated IgG. His liver injury resembled that in autoimmune hepatitis. He was diagnosed with Epstein-Barr virus (EBV) infection associated with autoimmunization because of his clinical course, fluctuation of anti EBV antibodies and positive EBV genome in circulating lymphocytes and serum. This case suggests a close relationship between EBV infection and autoimmunization or autoimmune-like hepatitis.

Aged↗

PubMed1999

Effect of organic anions and bile acid conjugates on biliary excretion of taurine-conjugated bile acid sulfates in the rat.

Biliary organic anion excretion is mediated by an ATP-dependent primary active transporter, canalicular multispecific organic anion transporter/multidrug resistance protein 2. On the other hand, a multiplicity of canalicular organic anion transporter/multidrug resistance protein 2 has been suggested. Therefore, to examine the effect of hydrophobicity on the substrate specificity of canalicular multispecific organic anion transporter/multidrug resistance protein 2, we examined the effect of organic anions and bile acid conjugates on biliary excretion of three taurine-conjugated bile acid sulfates with different hydrophobicity, taurolithocholate-3-sulfate, taurochenodeoxycholate3-sulfate, and taurocholate-3-sulfate in rats. Biliary excretions of these bile acid conjugates were delayed in Eisai hyperbilirubinemic rats. Biliary excretion of these bile acid conjugates was inhibited by sulfobromophthalein, whereas biliary excretion and taurocholate-3-sulfate was not inhibited by phenolphthalein glucuronide. Taurolithocholate-3-sulfate and ursodeoxycholate-3-glucuronide decreased biliary excretion of taurochenodeoxycholate-3-sulfate and taurocholate-3-sulfate, but ursodeoxycholate-3,7-disulfate did not affect biliary excretion of taurochenodeoxycholate-3-sulfate and taurocholate-3-sulfate. These findings indicate that very hydrophilic organic anions are not good substrates of canalicular multispecific organic anion transporter/multidrug resistance protein 2.

Animals↗