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Biomedical subjects

K Yamauchi

Publications and source records attributed to K Yamauchi.

At least 145 records · Page 8Linked to original sources
PubMed2000

Evaluation of the Space Collaboration System: its history, image quality and effectiveness for joint case conference.

A joint case-conference was conducted between the Departments of Radiology at Nagoya and Kobe Universities using the Space Collaboration System (SCS), which connects 39 national universities and institutes by communication satellite. In the conference, both sides presented cases using medical images such as those from CT, MRI, and DSA, and the cases were discussed between participants at the two universities. After the final conference, we distributed a questionnaire to solicit responses from the 43 participating radiologists on the quality of the transferred images and their overall impression of the conference. The responses showed that the CT, MRI, and DSA images were clear enough to allow discussion, whereas the plain X-ray images were not. Hence from the standpoint of image quality, the SCS may be unsuited for medical image diagnosis, but useful for presentation of case images in joint conferences and seminars.

Evaluation Studies as Topic↗
PubMed2000

[A survey of drug utilization in psychiatric hospitals in Japan: comparison of 1973, 1979, and 1993].

This paper investigated the trend in prescription patterns in the treatment of psychiatric inpatients using a database of our 1993 survey as well as reports of surveys conducted by Ito et al. in 1973 and 1979. To make the database of our survey comparable with surveys in 1973 and 1979, we extracted and analyzed 1,164 cases which met the criteria of Ito's survey, requiring that patients were diagnosed as having schizophrenia and were hospitalized for two years or longer. The results were as follows: 1) The most common number of different drugs per patient increased from 4 in 1973 and 1979 to 8 in 1993. That of psychotropics increased from 2 to 5. That of neuroleptics increased from 2 to 3. 2) The most commonly prescribed neuroleptics were haloperidol followed by levomepromazine and chlorpromazine. While the top three neuroleptics had not changed, the mean daily dose of haloperidol rose from 8.4 mg in 1979 to 15.3 mg in 1993.

Databases, Factual↗
PubMed2000

Predominant T helper 1 cells in patients with idiopathic portal hypertension.

BACKGROUND: The pathologic mechanism of idiopathic portal hypertension (IPH) is unknown. Because cytokines and the balance of T helper (h) 1 and Th2 CD4+ T cells have been reported to be important for regulating the immune response, in the present study we investigated the role of cytokines and the distribution of cytokine-producing cells in IPH patients. METHODS: Serum levels of tumor necrosis factor (TNF)-alpha, soluble TNF receptor-I, -II, interferon (IFN)-gamma and interleukin (IL)-4 were measured in IPH patients, fatty liver patients, chronic hepatitis patients and control subjects. The percentages of Th0, Th1 and Th2 CD4+ T cells were examined in peripheral and spleen lymphocytes in IPH patients by intracellular staining. RESULTS: Serum levels of TNF-alpha, soluble TNF receptor-I, interferon-gamma and IL-4 of IPH patients were not increased in comparison with control subjects. Only the mean value of soluble TNF receptor-II was significantly higher than that of control subjects and fatty liver patients. The ratios of Th1 and Th2 in both peripheral and spleen lymphocytes of IPH patients were significantly increased compared with the ratios found in peripheral lymphocytes of control subjects. The increase in the ratios was due to a decrease in the percentage of Th2 CD4+ T cells. CONCLUSIONS: These results suggest that the imbalance of Th1 and Th2 CD4+ T cells and TNF may be associated with the pathogenesis of IPH.

Adult↗
PubMed2000

[Pulmonary Mycobacterium gordonae infection treated with clarithromycin].

We reported a case of 51-year-old female immunocompetent patient with pulmonary Mycobacterium gordonae infection. The patient complained persistent cough and sputum and occasionally hemosputum. Chest radiograph and computed tomography (CT) of the lung showed bronchiectasis and small nodules in middle lobe. Bronchofiberscopy was performed twice, and bronchial washing specimen repeatedly revealed acid-fast bacilli. The organism was identified as Mycobacterium gordonae by biochemical tests and direct sequence method. She was treated with clarithromycin (400 mg/day) over 6 months and the chest CT findings showed improvement. The case was considered to be sensitive to clarithromycin in vitro drug susceptibility test. The case suggested that clarithromycin was a useful therapeutic agent to Mycobacterium gordonae infection.

Clarithromycin↗
PubMed1999

Higher avidity binding of apolipoprotein (E-AII) complex than of apolipoprotein E monomer to beta-amyloid.

Apolipoprotein E (apoE) is believed to be closely involved in the pathogenesis of Alzheimer's disease (AD) because of its ability to bind to beta-amyloid (Abeta), the primary component of senile plaques. The presence of cystein residues in apoE2 and apoE3 allows these isoforms to form disulfide-linked complexes, such as apo(E-AII) complex and apo(AII-E-AII) complex. A 50-kDa complex [which corresponded to apo(E-AII)-Abeta, because it reacted with any of the three antibodies, anti-apoE, anti-apoAII, or anti-Abeta] was detected by immunoblot analysis in native cerebrospinal fluid (CSF) obtained from nondementia patients with the apoE phenotype E3/E3. However, a band considered to represent apoE-Abeta was not observed. The dissociation constant (Kd) values obtained for the specific binding of recombinant apoE2, apoE3, and apoE4 to Abeta(1-42) were 48.1 +/- 2.2 nM, 63.7 +/- 2.1 nM, and 75.9 +/- 1.8 nM, respectively. In contrast, the binding affinity of the partially purified apo(E3-AII) complex to Abeta(1-42) was very high, the Kd being 5.5 +/- 0.5 nM. No basic difference was observed between lipidated and nonlipidated apoE in terms of the characteristics of the binding of apoE isoforms to Abeta(1-42); however, lipidation reduced the binding capacity of each isoform in a dose-dependent manner. These findings seem consistent with the generally accepted idea that apoE4 is a risk factor for AD, insofar as only apoE4 is unable to form a complex with apoAII owing to its lack of a cystein residue. In addition, it is possible that apoE3 monomer (and possibly apoE2 monomer), like apoE4 but unlike apo(E-AII) complex, can act as a risk factor in the pathogenesis of AD.

Amyloid beta-Peptides↗
PubMed1999

Estradiol-17beta stimulates the renewal of spermatogonial stem cells in males.

In this work, we examined the functions of the female hormone "estrogen" on spermatogenesis of the Japanese eel (Anguilla japonica). Estradiol-17beta (E(2)), a natural estrogen in vertebrates, was present in the serum and its receptor was expressed in the testis during the whole process of spermatogenesis. Spermatogonial stem cell renewal was promoted by E(2) implantation but was suppressed by tamoxifen (an antagonist of estrogen). In vitro, 10 pg/ml of E(2) was sufficient to induce spermatogonial stem cell division in cultured testicular tissue, therefore confirming the in vivo observations. These results clearly show that estrogen is an indispensable "male hormone" in the early spermatogenetic cycle.

Anguilla↗
PubMed1999

Xenopus cytosolic thyroid hormone-binding protein (xCTBP) is aldehyde dehydrogenase catalyzing the formation of retinoic acid.

Amino acid sequencing of an internal peptide fragment derived from purified Xenopus cytosolic thyroid hormone-binding protein (xCTBP) demonstrates high similarity to the corresponding sequence of mammalian aldehyde dehydrogenase 1 (ALDH1) (Yamauchi, K., and Tata, J. R. (1994) Eur. J. Biochem. 225, 1105-1112). Here we show that xCTBP was co-purified with ALDH and 3,3',5-triiodo-L-thyronine (T3) binding activities. By photoaffinity labeling with [125I]T3, a T3-binding site in the xCTBP was estimated to reside in amino acid residues 93-114, which is distinct from the active site of the enzyme but present in the NAD+ binding domain. The amino acid sequences deduced from the two isolated xALDH1 cDNAs (xALDH1-I and xALDH1-II) were 94.6% identical to each other and very similar to those of mammalian ALDH1 enzymes. The two recombinant xALDH1 proteins exhibit both T3 binding activity and ALDH activity converting retinal to retinoic acid (RA), which are similar to those of xCTBP. The mRNAs were present abundantly in kidney and intestine of adult female Xenopus. Interestingly, their T3 binding activities were inhibited by NAD+ and NADH but not by NADP+ and NADPH, whereas NAD+ was required for their ALDH activities. Our results demonstrate that xCTBP is identical to ALDH1 and suggest that this protein might modulate RA synthesis and intracellular level of free T3.

Aldehyde Dehydrogenase↗
PubMed1999

Development and differentiation of gonadotropin hormone-releasing hormone neuronal systems and testes in the Japanese eel (Anguilla japonica).

In this study we investigated the relationship between the development of the olfactory, preoptic, and midbrain gonadotropin-releasing hormone (GnRH) neuronal systems and testicular differentiation in eels (Anguilla japonica) from embryonic stages through adulthood (5.4-50 cm body length). GnRH-synthesizing neuronal populations were first observed in the youngest fish ( approximately 5.0 cm) at the rostrobasal and caudalmost olfactory bulbs immunoreactive to a "promiscuous" (nonspecific) GnRH antiserum (635.5), and in the preoptic area and midbrain tegmentum immunoreactive to chicken GnRH II antiserum. The eel brains lacked salmon and seabream GnRH immunoreactivity. The evidence from our study suggests that the olfactory, preoptic, and midbrain GnRH populations have origins independent from those of proliferative periventricular zones within the brain. However, the olfactory GnRH neurons could have migrated out of the olfactory placodes during ages earlier than those observed in this study. Although all three GnRH neuronal populations contribute to pituitary innervation to some degree, the preoptic GnRH innervation was pronounced in the pituitary when primordial germ cells (animals approximately 5.0 cm) differentiated into male germ cells (animals 14-16 cm) and, therefore, an association can be assumed between preoptic GnRH expression and testicular differentiation in the Japanese eel.

Anguilla↗
PubMed1999

Transsacral rectopexy for recurrent complete rectal prolapse.

The aim of this study was to examine the functional outcome of transsacral rectopexy performed with Dexon mesh for recurrent complete rectal prolapse. Anorectal function was assessed by anorectal manometry and defecography, before and from 1 year after surgery in five patients who were followed up for 1-3 years. The fecal incontinence score recovered from a preoperative mean score of 3.8 to a postoperative mean score of 1.2, and constipation was improved in four patients (80%). The straining anorectal angle (S-ARA), measured by defecography, improved from a preoperative value of 120.6 degrees +/- 6.9 degrees to a postoperative value of 98.5 degrees +/- 3.5 degrees (P < 0.05), and the perineal descent (PD) improved from a preoperative value of 16.2 +/- 2.5 cm to a postoperative value of 8.1 +/- 1.3 cm (P < 0.05). The maximal resting pressure (MRP) increased from a preoperative value of 20.5 +/- 3.7 cmH2O to a postoperative value of 40.5 +/- 4.8 cmH2O (P < 0.05). These findings indicate that transsacral rectopexy with Dexon mesh can achieve good control of recurrent complete rectal prolapse.

Aged↗
PubMed1999

Functional results of colonic J-pouch anastomosis for rectal cancer.

The purpose of this study was to clarify the functional outcomes of colonic J-pouch anastomosis (J-LAR) for lower rectal cancer in comparison with those of traditional straight anastomosis (S-LAR). A questionnaire regarding anorectal function was conducted 1 year after operation on patients who underwent J-LAR (n = 15) and S-LAR (n = 30). The clinical functions were assessed by an incontinence scoring system. The physiologic function was assessed by anorectal manometry and the balloon expulsion test. No patients demonstrated a diverting stoma. The bowel frequency (range) 1 year after operation was 4.8 (3-6) in the S-LAR group and significantly decreased to 1.8 (1-3) in the J-LAR group (P < 0.05). Complete evacuation was 50.2% (40%-60%) in the S-LAR group and significantly increased to 80.6% (60%-90%) in the J-LAR group (P < 0.05). Neorectal compliance was 2.2 (1.4-2.9) ml/mmHg in the S-LAR group and significantly increased to 3.1 (1.3-3.5) ml/mmHg in the J-LAR group (P < 0.01). No significant difference was observed between the two groups regarding the maximum resting or maximum voluntary squeezing pressure. In conclusion, our findings suggested colonic pouch anastomosis performed after a low anterior resection to support the compliance of the (neo)rectum to be an important factor for retaining a satisfactory bowel frequency.

Adult↗
PubMed1999

Dietary conjugated linoleic acid reciprocally modifies ketogenesis and lipid secretion by the rat liver.

The effects of dietary conjugated linoleic acid (CLA) and linoleic acid (LA) on ketone body production and lipid secretion were compared in isolated perfused rat liver. After feeding the 1% CLA diet for 2 wk, the concentration of post-perfused liver cholesterol was significantly reduced by CLA feeding, whereas that of triacylglycerol remained unchanged. Livers from CLA-fed rats produced significantly more ketone bodies; and the ratio of beta-hydroxybutyrate to acetoacetate, an index of mitochondrial redox potential, tended to be consistently higher in the liver perfusate. Conversely, cumulative secretions of triacylglycerol and cholesterol were consistently lower in the livers of rats fed CLA, and the reduction in the latter was statistically significant. Thus dietary CLA appeared to exert its hypolipidemic effect at least in part through an enhanced beta-oxidation of fatty acids at the expense of esterification of fatty acid in the liver.

Animals↗
PubMed1999

Distinct spatiotemporal expression of mRNAs for the PSD-95/SAP90 protein family in the mouse brain.

PSD-95 (SAP90), SAP102 and Chapsyn-110 (PSD-93) are members of the membrane-associated guanylate kinase family, and interact with N-methyl-D-aspartate (NMDA) receptor NR2A (GluRepsilon1) and NR2B (GluRepsilon2) subunits and with Shaker-type K+ channel subunits to cluster into a channel complex. In the present study, we examined their expression in developing and adult mouse brains by in situ hybridization with antisense oligonucleotide probes. PSD-95 and SAP102 mRNAs were prominently expressed at embryonic day 13 (E13) in the mantle zone of various brain regions, where NMDA receptor NR2B subunit mRNA is expressed at high levels. In the early postnatal period when active synaptogenesis takes place, both mRNAs became elevated and concentrated in the telencephalon and cerebellar granular layer, where NR2A and/or NR2B subunit mRNAs are abundantly expressed. Chapsyn-110 mRNA was, though at low levels, found over the mantle zone of embryonic brains, and the level was progressively increased in the telencephalon starting at perinatal stages. The spatial and temporal correlations in the brain in vivo suggest that the PSD-95/SAP90 protein family can interact with NMDA receptor subunits to cluster them into channel complex at both synaptic and non-synaptic sites before, during and after synaptogenic stages.

Aging↗
PubMed1999

Catastrophic failure of cementless total hip arthroplasty using a femoral component without surface coating.

Consecutive series of 90 hips that had had a primary cementless arthroplasty with use of straight collarless stems between January 1988 and September 1992 were reviewed. Twenty-eight hips with Omnifit Normalized Stems (Fit-N) and 45 hips with Omniflex Normalized Stems (Flex-N) without porous coatings were compared clinically and radiographically with 17 hips with Omnifit Microstructured Stems (Fit-M) with porous coating. The average follow-up periods for the 3 stems were 97 months, 73 months, and 93 months. Revision was performed or awaited in 9 cases (32.1%) in the Fit-N group, 18 cases (40.0%) in the Flex-N group, and 1 case (5.8%) in the Fit-M group. The average annual subsidence was 0.62 mm/y, 0.73 mm/y, and 0.17 mm/y. Osteolysis of more than 3 mm occurred in 28.6%, 37.8%, and 23.5%. Fit-N stems and Flex-N stems without porous coatings are not appropriate for cementless total hip arthroplasty.

Bone Cements↗
PubMed1999

A self-supervised learning system for pattern recognition by sensory integration.

Artificial neural networks are useful tools for pattern recognition because they realize nonlinear mapping between input and output spaces. This ability is tuned by supervised learning methods such as back-propagation. In the supervised learning methods, desired outputs of the neural network are needed. However, the desired outputs are usually unknown in unpredictable environments. To solve this problem, this paper presents a self-supervised learning system for category detection. This system learns categories of objects automatically by integrating information from several sensors. We assume that these sensory inputs are always ambiguous patterns that include some noises according to deformations of the objects. After the learning, the system recognizes objects, also controlling the priority of each sensor, according to the deformation of the sensory input pattern.In the simulation, the system is applied to several learning and recognition tasks using artificial or actual sensory inputs. In all tasks, the system found the categories. Particularly, we applied the new system to the learning of five Japanese vowels with the corresponding shapes of the mouth. As result, the system became to yield specific outputs corresponding to each vowel.

Journal Article↗
PubMed1999

Nucleotide sequences and characterization of genes encoding naphthalene upper pathway of pseudomonas aeruginosa PaK1 and Pseudomonas putida OUS82.

A 12,808-nucleotide containing DNA fragment cloned from naphthalene-utilizing (Nah+) Pseudomonas aeruginosa PaK1 was analyzed and compared with the genes (pah(OUS)) of a 14,462-nucleotide DNA fragment from Pseudomonas putida OUS82. The DNA sequence analyses demonstrated that the naphthalene upper-pathway genes and their deduced enzymes were very similar between the two bacteria: nucleotide similarities, 83-93%; amino acid similarities, 79-95%. These genes were also similar to those of the nah operon of plasmid NAH7; in particular, the OUS82 genes were similar to the nah genes, whereas the PaK1 genes were almost identical to the dox genes of Pseudomonas sp. C18. A region homologous with the 84-bp repeated sequence that Eaton (J. Bacteriol., 176, 7757-7762, 1994) has found at a site upstream of he nah operon was found only in a region downstream of the pah(PaK) gene cluster in PaK1 and on both sides of the pah(OUS) gene cluster in OUS82. A PaK1 gene, corresponding to an unknown gene (nahQ) in the nah operon, is located between the 1,2-dihydroxynaphthalene dioxygenase gene and the trans-o-hydroxybenzylindenepyruvate (tHBP A) hydratase-aldolase gene (nahE), and was suggested to be involved in the conversion of naphthalene to salicylate. Just downstream of the pah(PaK) gene cluster, a portion of a region was identical to one-third of the transposase gene (tnpA) in a phenol-catabolic plasmid pEST1226.

Journal Article↗
PubMed1999

Purification and characterization of thyroid-hormone-binding protein from masu salmon serum. A homolog of higher-vertebrate transthyretin.

We purified a thyroid-hormone-binding protein (THBP) from serum of masu salmon at the stage of smoltification when the concentrations of endogenous thyroid hormones in plasma reach the highest levels. All steps of sequential column chromatography suggest that this THBP is responsible for most L-3,5,3'-triiodothyronine-binding activity in serum at this stage. The molecular mass of this protein was estimated to be 60 kDa by gel filtration but only 15 kDa by SDS/PAGE, which suggests that it is comprised of four identical subunits. The amino acid sequence of its N-terminal portion was highly similar to those of vertebrate transthyretins. These molecular features indicate that masu salmon THBP is a homolog of transthyretins from tetrapods. However, in contrast with mammalian transthyretins, the affinity of masu salmon transthyretin for L-3,5,3'-triiodothyronine was three times greater than for L-thyroxine. This rank order affinity is similar to that of avian and frog transthyretins. Scatchard analysis revealed that masu salmon transthyretin possesses a single class of binding site for L-3,5,3'-triiodothyronine, with a Kd of 13.8 nM at 0 degrees C. Taken together with the data reported by Chang et al. [Eur. J. Biochem. (1999) 259, 534-542], these results suggest that transthyretin has changed from a L-3,5, 3'-triiodothyronine-carrier protein to a L-thyroxine-carrier protein during mammalian evolution.

Amino Acid Sequence↗