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Biomedical subjects

Y Wada

Publications and source records attributed to Y Wada.

At least 163 records · Page 9Linked to original sources
PubMed2000

Tandem mass spectrometric analysis of (13)C-containing ions from a mixture of homologous peptides differing by one mass unit at a residue.

Tandem mass spectrometry of a mixture of two peptides that differ from each other by a single mass unit due to mutation is presented. The mutant beta-globin of hemoglobin Hoshida is present along with the normal counterpart, and the amino acid substitution of glutamine for glutamic acid is located within tryptic peptide T5 of M(r) 2057. 9. The mass of the mutated peptide is 1 u lower. In the isotopic cluster for the doubly charged ion of the peptide T5, the resolved ion with mass of 1030.0 represents the normal peptide with 93 (12)C atoms and the mutated one with 92 (12)C and one (13)C atoms. Collision-induced dissociation (CID) of this composite ion identified the mutation by presenting a key fragment derived from the (12)C-only mutant peptide, as reported in a previous study. Similarly, when an ion containing multiple (13)C atoms was selected as a precursor for CID, the mutation could be identified, even in large fragments, by a marked change in the shape of the isotopic cluster for the consecutive product ions. This study demonstrates the merit of selecting a resolved ion rather than the whole isotopic cluster as a precursor in the CID measurements of large peptides or proteins for characterizing heterozygous mutations.

Amino Acid Sequence↗
PubMed2000

SLC7A7 genomic structure and novel variants in three Japanese lysinuric protein intolerance families.

Lysinuric protein intolerance (LPI) is a rare inherited disease caused by defective transport of the dibasic amino acids at the basolateral membranes of epithelial cells in the renal tubules and small intestine. The metabolic defect leads to brain dysfunction caused by hyperammonemia with a functional impairment of the urea cycle. Recently, mutations in the human SLC7A7 cDNA coding for y(+)LAT-1, which express dibasic amino acid transport activity, were reported to be responsible for LPI. In the present study, we examined the genomic structure of SLC7A7 by DNA sequencing of PCR products, and determined that the gene had 11 exons and 10 introns spanning about 18 kb of genomic DNA. We also identified an alternative RNA splicing at the 5' untranslated region of the SLC7A7 mRNA in human peripheral blood leukocytes, cultured lymphoblasts, and fibroblasts. As a result of mutational analysis of SLC7A7 in three Japanese LPI families, we found a nonsense mutation (R410X), a splicing mutation(911+1G>A) in intron 4, and four silent polymorphisms (201C/T, 445A/G, 784C/T, 946T/C). Identification of the genomic structure of SLC7A7 may provide a molecular basis for a genetic survey for LPI.

5' Untranslated Regions↗
PubMed2000

Identification of a larger than 3 Mb deletion including JAG1 in an Alagille syndrome patient with a translocation t(3;20)(q13.3;p12.2).

Alagille syndrome (AGS) is an autosomal dominant, developmental disorder affecting multiple organ systems including liver, heart, vertebrae, eye and face. Recurrent deletions of the 20p12 region led to the localization, and ultimately to the identification of mutations in the Jagged1 gene (JAG1) in AGS patients. A translocation t(3;20)(q13.3;p12.2) in an AGS patient was characterized using fluorescent in situ hybridization (FISH). The involvement of 3q and 20p in this translocation was demonstrated using probes for 3q and 20p. Three overlapping YAC clones, 940D11, 953A2, and 675G11 extending to nearly 4 Mb including the JAG1 were used as probes for FISH analysis to define the translocation breakpoint. The translocated chromosome was found to have a deletion of more than 3 Mb including the entire JAG1 gene. The observation of an accompanying large deletion, revealed by molecular characterization of the t(3;20) translocation, is similar to the only other translocation reported in an AGS patient; a t(2;20) translocation was also found to have a large deletion of the JAG1 region at 20p12.

Alagille Syndrome↗
PubMed2000

Posthypoxic reoxygenation-induced neurotoxicity prevented by free radical scavenger and NMDA/non-NMDA antagonist in tandem as revealed by dynamic changes in glucose metabolism with positron autoradiography.

Using a positron autoradiography technique, dynamic changes in the cerebral glucose metabolic rate (CMRglc) induced by hypoxia/reoxygenation were investigated in living brain slices. After incubating fresh rat brain slices (300 microm thick) with [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) in oxygenated Krebs-Ringer solution at 36 degrees C, serial two-dimensional time-resolved images of [(18)F]FDG uptake in the slices were obtained on imaging plates. As compared to the unloaded control values, with hypoxia-loading [(18)F]FDG uptake increased markedly, suggesting enhanced glycolysis. The net influx constant (K) of [(18)F]FDG at pre-hypoxia-loading and after reoxygenation with loading hypoxia for various periods of time was quantitatively evaluated by applying the Patlak graphical method to the image data. Regardless of the brain region, with hypoxia of </=10-min duration, the K value returned to the preloading level, whereas with hypoxia of >/=20 min duration only partial or no recovery was seen, indicating irreversible neuronal damage. The 30-min administration of either N-methyl-D-aspartate (NMDA)/non-NMDA antagonist or a free radical scavenger at the same time as reoxygenation after 20 min hypoxia showed a neuroprotective effect inhibiting the decrease in the post-hypoxia-loading K value. In contrast, no such neuroprotective effect was evident with administration of either of these agents only during hypoxia loading, possibly indicating that immediately after reoxygenation neuronal damage was induced mediated by excitatory amino acids and free radicals in tandem. These results demonstrate that serial quantitative evaluation of CMRglc using this technique may be of use in investigating the brain tissue injury associated with hypoxia/reoxygenation as well as clarifying the underlying mechanisms and protective effect of various drugs against such injury.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2000

Oblique plication for repair of the atrialized ventricle and tricuspid incompetence of Ebstein's anomaly.

An 8-year-old girl who weighed 42 kg presented Ebstein's anomaly with severe tricuspid incompetence, and mild systemic cyanosis during exercise. A new reconstructive procedure for this complex anomaly was used. Oblique transference of the displaced posterior leaflet was performed, which resulted in plication of the atrialized ventricle and reduction in the tricuspid annular diameter. This procedure requires neither detachment nor closure of the tricuspid valve.

Child↗
PubMed2000

Repair of partial anomalous pulmonary venous connection with a minimal atriotomy.

We present an alternative surgical technique for the repair of a partial anomalous pulmonary venous connection to the higher segment of the superior vena cava. Although the atriotomy is limited in this technique, a sufficiently large systemic venous chamber overlapping to the outside of the superior vena cava can be created.

Adolescent↗
PubMed2000

Dome-shaped proximal tibial osteotomy using percutaneous drilling for osteoarthritis of the knee.

We have improved a surgical technique for proximal tibial osteotomy that involves percutaneous drillings. We performed the modified dome-shaped proximal tibial osteotomy on 44 knees in 42 patients (8 men and 34 women) with an average age of 66 years (range 50-78 years) for osteoarthritis of the knee. The mean follow-up period was 39 months (range 24-63 months). The varus angle was 4 degrees +/- 3.6 degrees (mean +/- SD) preoperatively, and the valgus angle was 12 degrees +/- 3.3 degrees postoperatively. Pain relief was obtained in all cases postoperatively. Transient pin tract infection occurred in one case, but it resolved completely following local irrigation. Intercondylar fracture of the upper fragment with no displacement was noted in two patients. They were treated with AO cancellous screw fixation, and improvement of pain was obtained in both cases. Osteotomy drill guide instruments are useful for accurately performing dome-shaped osteotomy. Our proximal tibial dome osteotomy with an external fixator allowed early motion and accurately maintained the angle of correction.

Aged↗
PubMed2000

Osteocalcin-directed gene therapy for prostate-cancer bone metastasis.

Osteocalcin (OC) is a major noncollagenous bone protein whose expression is limited almost exclusively to osteotropic tumors and mature calcified tissue (differentiated osteoblasts). The function of OC, a highly conserved gamma-carboxyglutamic acid-containing protein, relies in part on its ability to bind hydroxyapatite and act as a chemoattractant for bone-resorbing cells. Serum osteocalcin levels are used clinically as an index of active bone turnover. Research in our laboratory has revealed that OC is expressed in several solid tumors, including osteosarcoma and ovarian, lung, brain, and prostate cancers. Evidence arising from reverse-transcription polymerase chain reaction (RT-PCR; detection of OC mRNA), immunohistochemical staining (detection of OC protein), and transient transfection and reporter assay (detection of OC mRNA transcription) reveals that OC expression is up-regulated in numerous solid tumors, with its expression being further elevated in androgen-independent prostate cancers. A recombinant, replication-defective adenovirus, Ad-OC-TK (OC promoter-driven herpes-simplex-virus thymidine kinase) was constructed and, when combined with the appropriate prodrug, either ganciclovir (GCV) or acyclovir (ACV), was found to be effective at destroying prostate-cancer cell lines in vitro and prostate tumor xenografts in vivo in both subcutaneous and bone sites. Additionally, via use of the OC promoter the supporting bone stromal cells are cotargeted when the prostate cancer interdigitates with bone stroma at the metastatic skeletal sites. Thus, maximal tissue-specific cell toxicity is achieved by the interruption of cellular communication between the prostate cancer and the bone stroma. We describe herein the preclinical foundation as well as the design and implementation of an ongoing phase I clinical trial at the University of Virginia that targets androgen-independent metastatic prostate cancer using the Ad-OC-TK vector.

Adenoviridae↗
PubMed2000

A novel color M-mode Doppler echocardiographic index for left ventricular relaxation: depth of the maximal velocity point of left ventricular inflow in early diastole.

Color M-mode Doppler echocardiography (CMD) has been utilized in assessing left ventricular (LV) filling dynamics. We tested a novel CMD index, the depth of the spatiotemporal maximum of early diastolic inflow (D-maxV) in the left ventricle, to clarify its significance in assessing LV diastolic function. In 26 normal subjects and 32 patients with ischemic heart disease, D-maxV was determined with CMD as the distance from the mitral valve opening point to the center of the aliasing area in early diastole. Transmitral flow velocity was measured with pulsed Doppler. During routine catheterization, high-fidelity LV pressure measurements yielded diastolic variables in patients. D-maxV was significantly lower in the patients than the normals (13.0+/-7.0 vs 23.4+/-6.8 mm, P < 0.0001). D-maxV exhibited significant linear correlations with the minimal first derivative of LV pressure (r = 0.72, P < 0.01), the time constant of isovolumic relaxation (r = -0.67, P < 0.01), and LV minimal pressure (r = -0.53, P < 0.02) in the patients with wide ranges of peak early to late inflow velocity ratio (0.43-3.9) and deceleration time of early filling (79-293 ms). D-maxV showed an inverse correlation with LV end-diastolic pressure (r = -0.53, P < 0.02) and no significant correlation with mean pulmonary capillary wedge pressure. Moreover, Kaplan-Meier analysis focusing on the patients with myocardial infarction revealed that the group with D-maxV < 10.4 mm (n = 13) exhibited a lower cumulative cardiac event-free rate than that with D-maxV > or = 10.4mm (n = 14) (49.4% vs 92.9% at 5 years, P < 0.05). The depth of the spatiotemporal maximum of early diastolic LV inflow velocity reflects LV relaxation and is free of pseudonormalization. Evaluation of the LV relaxation separately from preload may have a prognostic value for myocardial infarction.

Adult↗
PubMed2000

Effect of overexpression of very low density lipoprotein receptor on cell growth.

The very low density lipoprotein (VLDL) receptor is a member of the LDL receptor gene family and binds only apoE-containing lipoproteins. Although the VLDL receptor has been shown to play an important role in the proliferation of vascular smooth muscle cells and the formation of foam cells as primary responses of atherogenesis, its actual functions are still unclear. To understand the biological roles of the VLDL receptor in foam cell formation and cell growth, we tried to overexpress VLDL receptors in various cells. When COS-7 cells were transfected with an expression plasmid containing VLDL receptor cDNA, cell growth was inhibited by overexpression of the receptor and this growth inhibition was ligand-independent. The O-linked glycosylation region, but not the cytoplasmic domain, of the receptor appeared to be responsible for this growth inhibition. On the other hand, VLDL receptor expression induced enhanced incorporation of lipids and cytoplasmic enlargement. These changes were dependent on the exogenous ligand and the cytoplasmic domain of the receptor. These results suggest that the VLDL receptor functions as a regulator of cell growth and differentiation, which may be distinct from its lipid-incorporating function.

Animals↗
PubMed2000

Effects of hyaluronan on the healing of rabbit meniscus injured in the peripheral region.

The effect of hyaluronan (hyaluronic acid; HA) on the healing of rabbit meniscus injured in the peripheral region was assessed. A longitudinal tear was created in the peripheral region of the medial meniscus in 20 mature New Zealand white rabbits. One week after surgery, HA was injected into the left knee joint once a week for 5 weeks (HA group), while saline was injected into the right knee (control group). Six and 12 weeks after surgery, gross morphology, histology, and biochemical evaluations were performed. On gross morphological examination, there was evidence of meniscal healing in both groups, but the healing rate of the HA group was significantly higher than that of the control group at 12 weeks. Histologically, meniscal healing started at the tibial portion of the meniscal injury at 6 weeks in both groups, then advanced in the direction of the femoral surface at 12 weeks in the HA group. Biochemically, water and glycosaminoglycan contents did not differ significantly between the two groups. Hyaluronan maintained the healing process of the injured menisci, especially in the femoral surface, up to 12 weeks after injury.

Adjuvants, Immunologic↗