Search PubMed⌕ Search

Biomedical subjects

Atsushi Yamada

Publications and source records attributed to Atsushi Yamada.

33 records · Page 2Linked to original sources
PubMed2004

A highly effective method for removing suspended poliovirus from water using a positively-charged carbon felt electrode.

We developed an effective system to eliminate poliovirus from modified tap water using a positively-charged carbon felt electrode. The zeta potential of polioviruses was measured using laser microscopic electrophoresis. Poliovirus adsorption to the electrode was examined by indirect immunofluorescence. The tissue culture infective dose (TCID) of poliovirus type 2 (Sabin strain) was determined using human rhabdomyosarcoma cells (RD cells). Poliovirus VP2 gene copy numbers were assessed by reverse transcription followed by a quantitative real-time polymerase chain reaction. The mean zeta potential of the viruses was -20 mV. Relatively large numbers of polioviruses (10(3) or 4 x 10(3) TCID(50)/0.1 ml) could be removed by adsorption to the electrode, drastically decreasing TCID and copy numbers of poliovirus genome in the water. Virus elimination was dependent on electric current and time. Thus, the positively-charged carbon felt electrode effectively adsorbed polioviruses. The system may prove applicable to the elimination of certain viruses from water.

Adsorption↗
PubMed2004

Torsion potential works in rhodopsin.

We investigate the role of protein environment of rhodopsin and the intramolecular interaction of the chromophore in the cis-trans photoisomerization of rhodopsin by means of a newly developed theoretical method. We theoretically produce modified rhodopsins in which a force field of arbitrarily chosen part of the chromophore or the binding pocket of rhodopsin is altered. We compare the equilibrium conformation of the chromophore and the energy stored in the chromophore of modified rhodopsins with those of native rhodopsins. This method is called site-specific force field switch (SFS). We show that this method is most successfully applied to the torsion potential of rhodopsin. Namely, by reducing the twisting force constant of the C11=C12 of 11-cis retinal chromophore of rhodopsin to zero, we found that the equilibrium value of the twisting angle of the C11=C12 bond is twisted in the negative direction down to about -80 degrees. The relaxation energy obtained by this change amounts to an order of 10 kcal/mol. In the case that the twisting force constant of the other double bond is reduced to zero, no such large twisting of the bond happens. From these results we conclude that a certain torsion potential is applied specifically to the C11=C12 bond of the chromophore in the ground state of rhodopsin. This torsion potential facilitates the bond-specific cis-trans photoisomerization of rhodopsin. This kind of the mechanism is consistent with our torsion model proposed by us more than a quarter of century ago. The origin of the torsion potential is analyzed in detail on the basis of the chromophore structure and protein conformation, by applying the SFS method extensively.

Binding Sites↗
PubMed2004

Alveolar ridge notching as a predictor for secondary bone grafting in incomplete alveolar clefts.

OBJECTIVES: To clarify the need for secondary alveolar bone grafting (ABG) in incomplete alveolar clefts identified clinically from its appearance and test the usefulness of alveolar ridge notching in the edentulous stage as a predictor for ABG. DESIGN: A prospective, cross-sectional study comparing three groups of patients at two stages. PATIENTS: Twenty-four patients with unilateral incomplete cleft of primary palate who underwent either no surgery or cheiloplasty only. METHODS: Cleft severity was assessed at two stages. Initially, the appearance of untreated clefts was assessed before cheiloplasty or at 3 months of age in the patient without cheiloplasty and graded by severity into three groups. Later alveolar bone defects were assessed with computed tomography in the primary or mixed dentition period. A decision regarding the requirement for ABG was then made. Finally, the relationship between untreated clefts and the need for ABG was determined. MAIN OUTCOME MEASURES: Nine (75%) of 12 patients with alveolar ridge notching in the edentulous stage were diagnosed as fulfilling the criteria for ABG. RESULTS: The alveolar bone defects correlated with the severity of untreated cleft conditions (Spearman r = 0.65, p =.002). The need for ABG was greater in patients with alveolar ridge notching, compared with those without notching (9/12 versus 0/12, p =.00034). CONCLUSIONS: Most patients with incomplete alveolar clefts clinically identified in the edentulous stage required ABG, and alveolar ridge notching in the edentulous stage could therefore serve as a predictor for ABG.

Alveolar Process↗
PubMed2004

Mandibular widening by distraction osteogenesis in the treatment of a constricted mandible and telescopic bite.

OBJECTIVE: Documentation of the application of mandibular widening by distraction osteogenesis and orthodontics. PATIENTS: Three patients with telescopic bite resulting from an extremely constricted mandible related to hypoglossia-hypodactyly syndrome. INTERVENTION: Mandibular widening by distraction osteogenesis using an extraoral device and subsequent orthodontic treatment. RESULTS: The extremely constricted mandible and telescopic bite were dramatically improved by mandibular widening using distraction osteogenesis and subsequent orthodontics. Two of the three patients had transient complications; one reported temporomandibular joint pain and the other showed evidence of periodontal damage. CONCLUSION: Mandibular widening by distraction osteogenesis is an effective technique for the treatment of telescopic bite resulting from an extremely constricted mandible.

Child↗
PubMed2004

[Laboratory medicine in the field of emergency medicine and disaster medicine--Old-And-New tools of emergency medical service].

We reviewed the characteristics of the field of laboratory medicine concerning emergency medicine and disaster medicine. Gram's stain was apt to be made light of by clinicians, but it has been reviewed again. A modern sophisticated analysis system is expected for the consequence management of NBC terrorism and mass poisoning, but we would like to emphasize the importance of the basic physical strength of laboratory medicine, such as Gram's stain, to the meaning of old-and-new technology.

Clinical Laboratory Techniques↗
PubMed2003

Novel IRF6 mutations in Japanese patients with Van der Woude syndrome: two missense mutations (R45Q and P396S) and a 17-kb deletion.

Three Japanese families with Van der Woude syndrome (VWS) were screened for mutations in the interferon regulatory factor 6 gene (IRF6) by sequencing its entire coding region. Two novel missense mutations, R45Q in exon 3 and P396S in exon 9, were identified in families 1 and 2, respectively. In family 3, no causative base change was found by the sequencing analysis, but a deletion involving exons 4-9 was suggested by multiplex PCR analysis. To confirm the deletion and to determine its 5'- and 3'-boundaries, we amplified a DNA fragment containing a heterozygous polymorphic site in exon 2 by using a 5'-upstream forward PCR primer and eight different reverse primers located 3'-downstream of exon 2. The amplified product was subjected to nested PCR to generate a DNA fragment containing the polymorphic site. When a reverse primer located within the deletion was used for the first PCR amplification, only the nondeletion allele was detected after the second PCR. Repeated analyses with eight different reverse primers allowed us to map the boundaries of the deletion, and subsequently a heterozygous 17,162-bp deletion involving exons 4-9 was identified. Since IRF6 mutations in a significant portion of VWS patients remain undetected by conventional sequencing analysis, it may be important to search for a large deletion in those patients. Our simple methods to identify deletions and to determine the boundaries of a deletion would facilitate the identification of such patients.

Cleft Lip↗
PubMed2003

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of phosphorylated compounds using a novel phosphate capture molecule.

This paper introduces a simple, rapid, and sensitive procedure for the analysis of phosphorylated compounds (ROPO(3) (2-)) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The method is based on a characteristic mass shift and a total-charge change (from -2 to +1) of the phosphate residue due to complexation of ROPO(3) (2-) with a dinuclear zinc(II) complex (1,3-bis[bis(2-pyridinylmethyl)amino]-2-propanolato dizinc(II) complex, Zn(2)L(3+)) in aqueous solution at physiological pH. Furthermore, the use of single zinc-isotope derivatives ((64)Zn(2)L(3+) and (68)Zn(2)L(3+)) enables improvement of the sensitivity and accuracy of the analysis.

Amino Acids↗
PubMed2003

Analytic review of 2372 free flap transfers for head and neck reconstruction following cancer resection.

Microvascular free tissue transfer has gained world-wide acceptance as a means of reconstructing post-oncologic surgical defects in the head and neck region. Since 1977, the authors have introduced this reconstructive procedure to head and neck reconstruction after cancer ablation, and a total of 2372 free flaps were transferred in 2301 patients during a period of over 23 years. The most frequently used flap was the rectus abdominis flap (784 flaps: 33.1 percent), followed by the jejunum (644 flaps: 27.2 percent) and the forearm flap (384 flaps: 16.2 percent). In the reported series, total and partial flap necrosis accounted for 4.2 percent and 2.5 percent of cases, respectively. There was a significant statistical difference ( p < 0.05) in complete flap survival rate between immediate and secondary reconstruction cases. The authors believe that the above-mentioned three flaps have been a major part of the armamentarium for head and neck reconstruction because of a lower rate of flap necrosis, compared to other flaps.

Cohort Studies↗
PubMed2003

A practical method for the remote control of the scanning electron microscope.

We have developed a remote control system for the scanning electron microscope (SEM). It is called Web-SEM and can be accessed by anyone through the Web browser. It is not necessary to install special software to control the SEM. Because the operating performance changes with the amount of traffic on the Internet, we have connected the Web-SEM to a LAN/Internet in order to overcome this. We have checked the performance of the remote control operation and we were able to perform focus adjustment, stage movement, etc. over the Internet by improving the method of operation and image transfer.

Data Display↗
PubMed2003

A missense mutation in the SH3BP2 gene on chromosome 4p16.3 found in a case of nonfamilial cherubism.

OBJECTIVE: Cherubism is a rare hereditary multilocular cystic disease of the jaws, characterized by its typical appearance. Although nonfamilial cases have been reported, it is difficult to distinguish nonfamilial cherubism from central giant cell granuloma. Recent studies have revealed the point mutations in the SH3BP2 gene on chromosome 4p16.3 in cherubism families. In this article, the SH3BP2 gene in nonfamilial cherubism was examined. PATIENT: A 21-year-old Japanese woman with nonfamilial cherubism. INTERVENTIONS: Genomic DNA was purified from a blood sample obtained from the patient and used for direct sequencing. In addition, a sample of the lesion, resected during surgery, was used for histologic and immunohistochemical purposes. RESULTS: Genomic DNA sequencing found a Pro418Arg mutation in the SH3BP2 gene of the patient. In a histochemical analysis, the multinucleated giant cells proved to be strongly positive for PGM-1, KP-1, and tartrate-resistant acid phosphatase and faintly positive for osteopontin. CONCLUSIONS: The missense mutation Pro418Arg was identified in the SH3BP2 gene from a nonfamilial case of cherubism. DNA diagnosis may play a significant role in the identification of cherubism.

Acid Phosphatase↗
PubMed2002

Neurovascular free-muscle transfer to treat facial paralysis associated with hemifacial microsomia.

Despite the wide spectrum of hemifacial microsomia manifestations, treatment mainly focuses on mandible and ear abnormalities, rather than on facial paralysis. In fact, the surgical treatment of facial paralysis associated with hemifacial microsomia is quite underdeveloped, because the degree of paralysis is frequently incomplete or partial. Timing and type of surgery are also difficult to determine. Neurovascular free-muscle transfer is now a standard procedure for the dynamic smile reconstruction of longstanding facial paralysis. This type of strategy has considerable potential in the treatment of facial paralysis in patients with hemifacial microsomia. We present here our experience with neurovascular free-muscle transfer for smile reconstruction in eight patients with facial paralysis associated with hemifacial microsomia. The age of the patients at the time of surgery ranged from 7 to 28 years old, (average, 13.9 years). Six were male patients and two were female patients. The two-stage method combining gracilis muscle transfer with cross-face nerve grafting was performed in three patients, whereas the one-stage transfer of the latissimus dorsi muscle was performed in five. To construct a natural or near-natural smile, the muscles were transferred into the paralyzed cheek in all except one patient, in whom the latissimus dorsi muscle was transferred into the sublabial area to reconstruct a paralyzed lower lip. A dermal flap segment vascularized with perforating vessels from the latissimus dorsi muscle was simultaneously inserted into the underdeveloped cheek for soft-tissue augmentation in this patient. Muscle contraction was evident in all patients between 4 and 8 months after muscle transfer. Our present series revealed that neurovascular free-muscle transfer is a good option not only for smile reconstruction but also for restoration of the facial contours of patients with hemifacial microsomia. Compared with the two-stage method combining gracilis muscle transfer with cross-face nerve grafting, the one-stage method using the latissimus dorsi muscle has some advantages, including a one-stage operation, a shorter recovery period, and the absence of sequelae that occur after harvesting a sural nerve.

Adolescent↗
PubMed2002

Lack of evidence for a significant association between nonsyndromic cleft lip with or without cleft palate and the retinoic acid receptor alpha gene in the Japanese population.

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is one of the most common craniofacial malformations. Both genetic and environmental factors are thought to be involved in the pathogenesis. The retinoic acid receptor alpha ( RARA) is one of the candidate genes for the pathogenesis of NSCLP. An association between a PstI restriction fragment length polymorphism or D17S579 microsatellite marker polymorphism of the RARA gene and NSCLP was previously suggested, but no nucleotide change that may influence the gene expression or the protein sequence has been reported to date. To investigate the possible association between the RARA gene and NSCLP in Japanese patients, we performed a transmission disequilibrium test (TDT) using three microsatellite markers at the RARA locus in 48 parent-offspring trios. The allele-wise TDT did not show evidence of an association between the RARA gene and NSCLP. We also screened nucleotide changes in eight patients with family histories using exon-by-exon direct sequencing. We found a novel nucleotide change (1161C>T) that is located in exon 1 of the RARA gene in one patient whose father also had the disease. Because the 1161C>T was inherited from the patient's healthy mother, the mutation was not considered to be responsible for NSCLP. We then screened all probands for the nucleotide changes in the promoter region of the RARA gene using denaturing high-performance liquid chromatography. A novel nucleotide length polymorphism of a thymidine tract was identified in three patients. No association between this polymorphism and NSCLP was observed. Our findings suggest that the RARA gene variations do not contribute to the development of NSCLP in the Japanese population.

Alleles↗
PubMed2002

Treatment for prolapse of the sigmoid neovagina in Mayer-Rokitansky-Kuster-Hauser syndrome.

BACKGROUND: Colpopoiesis using the sigmoid colon may be used in treatment of patients with Mayer-Rokitansky-Kuster-Hauser syndrome. Prolapse of a sigmoid neovagina is rare and its treatment is not yet standardized. CASES: Two patients developed severe prolapse of a neovagina derived from the sigmoid colon. One patient underwent resection of the redundant sigmoid and an abdominal suspension procedure; however, the prolapse has recurred. The other patient was treated by removal of the entire sigmoid artificial vagina. An alternative neovagina was reconstructed with a pudendal thigh flap. She has no signs of recurrent prolapse and is satisfied with sexual intercourse. CONCLUSION: Replacement therapy by a connected skin graft may be an excellent optional method as a radical treatment for prolapse of a sigmoid neovagina.

Adolescent↗
PubMedDate not supplied

Microarray analysis using amplified mRNA from laser capture microdissection of microscopic hepatocellular precancerous lesions and frozen hepatocellular carcinomas reveals unique and consistent gene expression profiles.

The indirect labeling cDNA microarray technique was used to evaluate gene expression profiles of pure cell populations from frozen sections of carcinomas and adenomas harvested from precancerous hepatocellular lesions by using laser capture microdissection (LCM). The levels of differentially expressed genes were investigated using a cDNA microarray with 9,984 features with only 2 ug of two-round amplified aRNA, equivalent to 35 cells from LCM-adenomas and frozen samples of carcinomas from simian virus 40 (SV40) large T antigen transgenic rats. A total of 855 genes were identified as being 3-fold or more differentially expressed in carcinomas or adenomas as compared to normal tissue controls. Among these 855 genes, 71 genes were differentially expressed in both carcinomas and adenomas. Commonly up-regulated genes in both carcinoma and adenomas were 28 while 41 of the 71 genes were commonly down-regulated. Two genes, Igh1 (immunoglobulin heavy chain 1(Serum IgG2a), Image clone ID: 875880) and EST clone (AI893585, Image clone ID: 596604) were more than 7-fold up-regulated in carcinomas and 6-fold down-regulated in adenomas. In Cy5 and Cy3 reciprocal experiments for screening out false positive signals, the amplified carcinomas showed higher Pearson Correlation Coefficient values (-0.94 and -0.92) than the LCM-amplified adenoma samples (-0.79 and -0.84). LCM-amplified samples provided higher signal intensities over backgrounds and a greater average of Cy5:Cy3 ratios. Expression levels of mRNAs from selected genes, determined by using traditional dot blot analysis, revealed that 36 of 40 tested expression profiles were consistent with the microarray data. Thus, amplified aRNA harvested from homogeneous cell types using LCM can be applied to study gene expression profiles by use of microarray analysis.

Animals↗