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Biomedical subjects

K Yamada

Publications and source records attributed to K Yamada.

At least 343 records · Page 19Linked to original sources
PubMed2001

Survival and viral load in four groups of HIV-1 infected hemophiliacs compared by three-way data clustering.

We assigned a total of 131 hemophiliacs infected with HIV-1 into four clusters by applying a 3-way data analysis method. Sequentially acquired CD4+ and CD8+ cell counts obtained longitudinally over an observation period from 1986 to 1992 were analyzed. During the successive observation in this interval, a clustering of patients is not always coincident over all the times, because the cell counts vary with time. Therefore, the 3-way data clustering is to obtain the optimal result of the classification of patients through all the interval of observation. Examining patients' survival after that period, the cumulative mortality rate was highest among the 36 hemophiliacs in Cluster 1. Less mortality was found in Cluster 2, consisting of 49 hemophiliacs and none was reported in Clusters 3 and 4, which included 33 and 13 hemophiliacs, respectively. However, a significantly lower blood viral copy number was found in Cluster 3 than in Cluster 4. A total of six long-term non-progressors was found, five in Cluster 3 and one in Cluster 4, while none was found in Cluster 1 or 2. As demonstrated in this analysis, 3-way data clustering may represent a good data mining technique for handling various types of clinical data.

CD4 Lymphocyte Count↗
PubMed2001

Proton chemical shift imaging in normal pressure hydrocephalus.

BACKGROUND AND PURPOSE: Differentiation of normal pressure hydrocephalus (NPH) from other types of dementia and the selection of appropriate candidates for shunt surgery remain a clinical challenge. The aims of this study were to assess the efficacy of cerebral metabolites depicted by proton chemical shift imaging (1H-CSI) in distinguishing NPH from other dementias and to examine the relationship between metabolite changes and the outcome of shunt surgery. METHODS: 1H-CSI measurements were obtained in nine patients with clinical diagnosis of NPH; six patients with other types of dementia, including Alzheimer and Pick disease; and five control subjects. The 1H-CSI sequence consisted of a double spin-echo sequence with imaging parameters of 2000/135/4-2 (TR/TE/acquisitions). Volumes of interest were selected from a section through the lateral ventricles. The peak areas and ratios of N-acetylaspartate, creatine, choline, and lactate were calculated. In two patients, follow-up 1H-CSI and N-isopropyl (123I)-p-iodoamphetamine brain perfusion imaging were available after treatment with continuous spinal drainage. RESULTS: Lactate peaks were observed in the lateral ventricles for all patients with NPH (lactate/creatine, 0.23 +/- 0.14) but not for patients with other types of dementia or control subjects. In all cases, we noted no significant differences in the peak ratios in the voxels located at the white matter near the lateral ventricles. In one patient with NPH, intraventricular lactate disappeared and regional CBF recovered after drainage. CONCLUSION: The intraventricular lactate level may be useful in differentiating NPH from other types of dementia.

Adult↗
PubMed2001

[Percutaneous hot ethanol injection therapy (PHEIT) for hepatocellular carcinoma].

Percutaneous ethanol injection therapy (PEIT) is widely performed as a local treatment for hepatocellular carcinoma (HCC). However, PEIT must be repeated because only a limited amount of ethanol can be injected in a single treatment. In addition, PEIT is only indicated for up to 3 tumors of 30 mm or less in diameter. We therefore invented a percutaneous hot ethanol injection therapy (PHEIT) to enhance the antitumor effect of PEIT. For this, we developed a liquid-heating and injection device to heat the liquid to the intended temperature and inject it from the tip of the needle safely and accurately using a puncture technique under ultrasonographic guidance. An experiment on normal rat livers demonstrated that injected ethanol at temperatures over 60 degrees C enhances the necrotizing effect on tissue. The technique was clinically applied to patients with HCC using ethanol heated to 60 degrees C or 70 degrees C. The total volume of the ethanol injection was smaller in PHEIT than in PEIT, and the frequency of injection was lower in PHEIT than in PEIT, while the necrotic area obtained by a single treatment was larger with PHEIT than with PEIT. PHEIT is a potential radical treatment for patients with multiple hepatoma with 4 more lesions or those with large hepatomas exceeding 30 mm in diameter that do not respond to PEIT.

Aged↗
PubMed2001

Lack of association between hepatocyte nuclear factor-1beta gene and common forms of type 2 diabetes in the Japanese population.

Mutations in the hepatocyte nuclear factor-1beta (HNF-1beta) gene have been shown to be a cause of maturity-onset diabetes of the young (MODY). We studied the contribution of the HNF-1beta gene to susceptibility to common forms of Type 2 diabetes in the genetically homogeneous Japanese population, by investigating the allelic association of Type 2 diabetes with two markers in the HNF-1beta region. The frequency of a nonsense mutation, R177X, which was previously reported in a Japanese family, was also studied by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method using a mismatch primer. A total of 200 subjects were studied. There was no significant difference in allele frequencies of either of the two polymorphisms studied between patients with Type 2 diabetes and control subjects, or between subgroups of patients subdivided by the presence of mild or severe diabetic nephropathy. None of the subjects studied had R177X mutation, giving a frequency of less than 1.1% in common forms of Type 2 diabetes in Japan. These results suggest that mutations in the HNF-1beta gene derived from a limited number of founders are not a major cause of common forms of Type 2 diabetes, even in the genetically homogeneous Japanese population.

Adult↗
PubMed2001

Study on real time control of non-point pollutants discharged from urban areas during a storm event.

In this research, we installed the storm water storage tank, which has three functions: pollutant control, flood control and water use, to the end pipe of a separate system. We examined the effect of real time control (RTC) introduction with the scenario selection in the study area in the catchment basin, which has measured data. As a result, a latter period centering-type case is satisfied with the pollutant reduction by the RTC and also at the water use tank, the best control settles COD concentration at about 0.45 mg/l. It was clarified how to use a RTC method as a measure of the discharge problem from an urban area during a storm event.

Cities↗
PubMed2001

Study of diffuse source pollution management for land use and drainage system planning.

This study aims to clarify the mass balance of pollutants during both dry periods and storm events and to discuss the effects of some strategies such as pollutant removal, land use planning and new drainage systems by simulation. Three subjects are discussed in this paper. First, the amount of pollutants entering Lake Biwa from an urban area have been roughly estimated by using data collected by the local government. Second, many additional samples were collected from road surfaces, house roofs and parking lots to consider the role of land use in pollutant runoff. Third, some ongoing BMP projects in an urban area are introduced. As a result, some ideas on how to solve the problem of diffuse pollution in urban areas have been obtained.

Agriculture↗
PubMed2001

Comparison of pollutant runoff in Lake Biwa tributaries, Japan and the Brunette River watershed, Canada.

This study is aimed at verifying runoff pollutant loadings from urban areas. Urban runoff has been considered an important source of diffuse pollution especially during storm events. This paper describes the pollutant runoff during storm events, mainly in terms of effects of watershed characteristics. Data collected from Lake Biwa tributaries, Japan, have shown fundamental information to control pollutant runoff into receiving water. Also, data from the Brunette River watershed, Canada, which is a highly urbanized watershed in the Vancouver region, have been used for a comparative analysis. In the results, available information for the environmental management of urban storm water runoff was obtained by comparing the data on pollutant runoff in both watersheds.

Canada↗
PubMed2001

[Two cases of effective weekly paclitaxel administration for metastatic breast cancer].

We report two cases of effective weekly paclitaxel (TXL) administration for metastatic breast cancer. TXL (80 mg/m2) was infused over 1 hour after short premedication on an outpatient basis. Administration was continued for 3 weeks followed by 1 week rest. Case 1: A 66-year-old woman was treated with adriamycin, cyclophosphamide, doxifluridine (5'-DFUR), fadrozole, medroxyprogesterone acetate (MPA) and pamidronate for pleural, mediastinal and supraclavicular lymph nodes and skull metastases. She complained of hoarseness and supraclavicular and mediastinal lymph nodes had developed, for which she received weekly TXL administration. Metastatic lymph nodes had disappeared 3 months after administration. Case 2: A 61-year-old woman was treated with CMF therapy, 5'-DFUR, tamoxifen, MPA fadrozole and pamidronate for bone metastasis and local recurrence. She received weekly TXL administration for an axillary recurrence and contralateral supraclavicular lymph node metastases. Metastatic and recurrent lesions had disappeared 3 months after administration. The toxic events were leukopenia (grade 1) and peripheral neuropathy (grade 1). No major adverse effects were observed in either case.

Aged↗
PubMed2001

A slow maturation of a cysteine protease with a granulin domain in the vacuoles of senescing Arabidopsis leaves.

Arabidopsis RD21 is a cysteine protease of the papain family. Unlike other members of the papain family, RD21 has a C-terminal extension sequence composed of two domains, a 2-kD proline-rich domain and a 10-kD domain homologous to animal epithelin/granulin family proteins. The RD21 protein was accumulated as 38- and 33-kD proteins in Arabidopsis leaves. An immunoblot showed that the 38-kD protein had the granulin domain, whereas the 33-kD protein did not. A pulse-chase experiment with Bright-Yellow 2 transformant cells expressing RD21 showed that RD21 was synthesized as a 57-kD precursor and was then slowly processed to make the 33-kD mature protein via the 38-kD intermediate. After a 12-h chase, the 38-kD intermediate was still detected in the cells. These results indicate that the N-terminal propeptide was first removed from the 57-kD precursor, and the C-terminal granulin domain was then slowly removed to yield the 33-kD mature protein. Subcellular fractionation of the Bright-Yellow 2 transformant showed that the intermediate and mature forms of RD21 were localized in the vacuoles. Under the acidic conditions of the vacuolar interior, the intermediate was found to be easily aggregated. The intermediate and the mature protein were accumulated in association with leaf senescence. Taken together, these results indicate that the intermediate of RD21 was accumulated in the vacuoles as an aggregate, and then slowly matured to make a soluble protease by removing the granulin domain during leaf senescence.

Animals↗
PubMed2001

Molecular mechanism of cholinergic dysfunction and cognitive deficits induced by amyloid beta-peptide.

Amyloid beta-peptide (A beta) plays a critical role in the development of Alzheimer's disease (AD). Much progress has been made in understanding this age-related neurodegenerative disorder; thus an insight into the cellular actions of A beta and resulting functional consequences may contribute to preventive and therapeutic approaches for AD. In this review, recent evidence of A beta-induced brain dysfunction, especially cholinergic impairment and memory deficits, is summarized. Moreover, proposed mechanisms for A beta-induced neurotoxicity such as oxidative stress, ion-channel formation, and A beta-receptor interaction are discussed.

Amyloid beta-Peptides↗
PubMed2001

Increase in the sensitivity of dengue diagnosis by combination of reverse transcriptase-polymerase chain reaction and passage on cell cultures.

We passaged 52 serum samples from dengue patients on C6/36 cells for 7 days and checked the culture fluids by RT-PCR. Two serum samples, which were negative by direct RT-PCR, became positive. One sample was collected on fever day 1 and the other on fever day 2. Results indicate that combination of reverse transcriptase-polymerase chain reaction (RT-PCR) with passage of serum samples on C6/36 cells increases the sensitivity of dengue diagnosis.

Cell Line↗
PubMed2000

Detection and characterization of a 36-kDa peptide in C-terminal region of a 24-kDa vacuolar protein (VP24) precursor in anthocyanin-producing sweet potato cells in suspension culture.

A 24-kDa vacuolar protein (VP24) was found to accumulate in anthocyanin-producing sweet potato cells (Ipomoea batatas Lam.) in suspension culture [Nozue et al., Plant Physiol. 115 (1997) 1065]. VP24 cDNA (accession No. AB025531) encodes a 96.3-kDa large precursor protein with a C-terminal propeptide which contains the eight putative transmembrane domains. The mature VP24 is probably involved in the formation of intravacuolar pigmented globules (cyanoplasts) in highly anthocyanin-containing vacuoles, but the biological function of the C-terminal region including the putative transmembrane domains is unknown. To confirm the expression and characterize the C-terminal region in the VP24 protein precursor in the anthocyanin-producing cells, polyclonal antibodies were developed against the fusion protein, including the C-terminal region, expressed in Escherichia coli. Western blot analysis showed that a 36-kDa peptide (VP36) localized in anthocyanin-containing vacuoles was expressed under continuous illumination, but not in darkness. The expression pattern of VP36 showed high similarity to VP24. These results suggested that VP36 may be derived from the large VP24 protein precursor; it includes several of the hydrophobic domains in the C-terminal region.

Journal Article↗
PubMed2000

Genomic organization, chromosomal localization, and the complete 22 kb DNA sequence of the human GCMa/GCM1, a placenta-specific transcription factor gene.

The genomic sequence of the human GCMa/GCM1 gene, a mammalian homologue of Drosophila melanogaster GCM, was determined. Drosophila GCM is a neural transcription factor that regulates glial cell fate. The mammalian homolog however, is a placenta-specific transcription factor that is necessary for placental development. The 22 kb DNA sequence spanning the GCMa gene contains six exons and five introns, encoding a 2.8 kb cDNA. Overall genomic organization is similar for the human and mouse. Several potential binding sites for transcription factors like GATA, Oct-1, and bHLH proteins were found in the 5'-flanking region of the human gene. A DNA motif for GCM protein binding exists in the 5'-flanking region that is highly homologous with that of the mouse gene. The location of this gene was mapped to chromosome 6 using fluorescence in situ hybridization.

Animals↗
PubMed2000

Neurobehavioral alterations in mice with a targeted deletion of the tumor necrosis factor-alpha gene: implications for emotional behavior.

Tumor necrosis factor-alpha (TNF-alpha) is emerging as an important modulator of the function of the central nervous system. In the present study, we investigated a role of endogenous TNF-alpha in cognitive and emotional function using mice with targeted deletions of the TNF-alpha gene. TNF-alpha-(-/-) mice showed normal diurnal rhythms of spontaneous locomotor activity and cognitive functions. Emotional behavior in the mutant mice, however, was significantly altered, which manifested in the performance in the open-field, elevated plus maze, and forced swimming tests. The altered performance in the elevated plus maze test was significantly alleviated by treatment with diazepam. Postmortem brain analysis of TNF-alpha-(-/-) mice revealed a significant increase in serotonin metabolism in the brain. These findings suggest a role for endogenous TNF-alpha in emotional behavior, which may possibly be related to alterations of serotonine metabolism.

Animals↗
PubMed2000

Bardet-Biedl syndrome type 3 in an Iranian family: clinical study and confirmation of disease localization.

Bardet-Biedl syndrome (BBS) is a group of autosomal recessive MCA/MR syndromes characterized by pigmentary retinopathy, postaxial polydactyly, hypogenitalism, obesity, and mental retardation. Five BBS loci have been identified; among them, BBS type 1 (BBS1) and type 3 (BBS3) are most common and most rare, respectively. We encountered an Iranian family that had seven affected members. All patients had a history of mild to severe obesity, but it was reversible in some patients by caloric restriction and exercise. All patients had pigmentary retinopathy, beginning as night blindness in early childhood and progressing toward severe impairment of vision by the end of the second decade. Polydactyly varied in limb distribution, ranging from four-limb involvement to random involvement or even to nonaffectedness. Six of the seven patients were not mentally retarded. Although kidney anomaly or an adrenal mass was pres- ent in two patients, the fact that one patient had seven children rules out reproductive dysfunction. Linkage analysis with microsatellite markers showed that the disease in the family was assigned to a region around marker loci at 3p13-p12 (maximum LOD score = 4.15 and recombination fraction straight theta = 0, at D3S1603 microsatellite marker), to which the BBS3 locus has been mapped. Haplotype analysis did not reduce the extent of the previously reported critical region of BBS3. A comparison of clinical manifestations of our patients with those of previously reported BBS3 patients did not support any type-specific phenotypes, though manifestations in our patients are similar to those in BBS3 patients of a family in Newfoundland.

Adolescent↗