Biomedical subjects

K Ihara

Publications and source records attributed to K Ihara.

At least 109 records · Page 6Linked to original sources

PubMed1997

An asymptomatic infant with isolated 3-methylcrotonyl-coenzyme: a carboxylase deficiency detected by newborn screening for maple syrup urine disease.

UNLABELLED: We describe an asymptomatic male infant with isolated 3-methylcrotonyl-coenzyme A carboxylase deficiency who came to medical attention by newborn mass screening due to elevated blood leucine. The diagnosis was made by abnormal urinary organic acids at 20 days of age and was confirmed by assay of the carboxylase activities in cultured skin fibroblasts. CONCLUSION: More attention should be paid to slight elevations of leucine levels in newborn mass screening. Urinary organic acid analysis should be performed in conspicuous cases.

Carbon-Carbon Ligases↗

PubMed1997

Tensor fasciae latae flap: alternative donor as a functioning muscle transplantation.

The functioning tensor fasciae late muscle was used for a patient with both a complete defect of the deltoid muscle and a defect of overlying skin. The configuration of the tensor fasciae latae including the length of the muscle belly as well as the muscle fiber arrangement was similar to that of the deltoid. In addition, the spatial relationship between the muscle, donor vessels, and motor nerve fulfilled the requirements for the recipient site of deltoid reconstruction. The transferred muscle successfully replaced the function of the deltoid and provided sufficient strength for elevation of the arm. Simultaneous skin coverage was also satisfactory. The case report here clearly indicates that the tensor fasciae latae muscle is a promising candidate for functioning muscle transplantation, and can also be applied for other disorders. However, several points such as limited motor nerve length should be considered when tensor fasciae latae is used as a functioning muscle.

Fascia Lata↗

PubMed1997

Haloarcula argentinensis sp. nov. and Haloarcula mukohataei sp. nov., two new extremely halophilic archaea collected in Argentina.

Strains arg-1T (T = type strain) and arg-2T, two new strains of extremely halophilic archaea, were isolated from the soils of the Argentine salt flats. The taxonomic features of arg-1T were similar to, but distinct from, those of the type strain of Haloarcula vallismortis and other Haloarcula species. On the 16S rRNA phylogenetic tree, strain arg-1T formed a cluster together with Haloarcula species. Strain arg-2T differed in its glycolipid composition but still was more closely related to the genus Haloarcula than to other established genera. We propose that strain arg-1T be classified as a member of a new species, Haloarcula argentinensis, and that strain arg-2T be classified as a member of Haloarcula mukohataei sp. nov., although arg-2T may belong to a new genus or a subgenus of the genus Haloarcula. The type strain of H. argentinensis is strain arg-1 (= JCM 9737), and the type strain of H. mukohataei is strain arg-2 (= JCM 9738).

Argentina↗

PubMed1996

Three-dimensional structure of a DNA repair enzyme, 3-methyladenine DNA glycosylase II, from Escherichia coli.

The three-dimensional structure of Escherichia coli 3-methyladenine DNA glycosylase II, which removes numerous alkylated bases from DNA, was solved at 2.3 A resolution. The enzyme consists of three domains: one alpha + beta fold domain with a similarity to one-half of the eukaryotic TATA box-binding protein, and two all alpha-helical domains similar to those of Escherichia coli endonuclease III with combined N-glycosylase/abasic lyase activity. Mutagenesis and model-building studies suggest that the active site is located in a cleft between the two helical domains and that the enzyme flips the target base out of the DNA duplex into the active-site cleft. The structure of the active site implies broad substrate specificity and simple N-glycosylase activity.

Amino Acid Sequence↗

PubMed1996

Requirement for two conserved cysteine residues in the Ada protein of Escherichia coli for transactivation of the ada promoter.

Cysteine residue 69 of the Escherichia coli Ada transcription factor, which accepts a methyl group from methylphosphotriester in methylated DNA, was substituted by each of 19 other amino acids. Only the mutant Ada (C69H), carrying a histidine substitution of Cys69, exhibited a limited degree of transactivating potential for the ada promoter in E. coli cells although the mutant protein was completely devoid of methylphosphotriester-DNA methyltransferase activity. Using a multicopy plasmid system for the expression of Ada protein, we have shown that Ada C69H has a transactivating capacity equivalent to that of wild-type Ada protein in the absence of an alkylating agent. This indicates that the zinc-binding capacity of histidine at residue 69 is likely to be sufficient for Ada to recognize and bind to the ada promoter. Furthermore, transactivation of the ada promoter by Ada C69H was enhanced up to 6-fold by treatment with methylating agents. An additional substitution was made with alanine in Ada C69H, replacing Cys321, the site for acceptance of a methyl group from O6-methylguanine and O4-methylthymine residues in DNA, with alanine. This renders the protein completely inactive as a methyltransferase but this derivative is constitutively active as a transactivator for the ada promoter. Therefore, acquisition of a methyl group at Cys321 apparently enhances the transactivating capacity of Ada protein on the ada promoter. We propose that the transcription-regulating function of Ada protein is under dual control by methylation of cysteine residues at positions 69 and 321; the former enhances DNA binding, while the latter enhances the transactivating capacity of the protein.

Amino Acid Sequence↗

PubMed1996

Novel bacterial rhodopsins from Haloarcula vallismortis.

New bacterial rhodopsins of the cruxrhodopsin (cR) tribe were identified in a type strain Haloarcula vallismortis. The genes encoding a bacteriorhodopsin-like ion pump (named cR-3), a halorhodopsin-like ion pump (chR-3) and a sensor rhodopsin (csR-3) were cloned and sequenced. Together with the data for vsRII (Seidel et al., Proc. Natl. Acad. Sci. USA 92, 3036-3040 (1995); cpR-3 in our notation), the primary structures of a set of four rhodopsins are now all known only in this species. They are separated by almost the same distances in homology, suggesting that they have derived from a single ancestral rhodopsin. The degree of conservation in the amino acid sequence of each helix showed that helices C and G are relatively well conserved in all rhodopsins, whereas helices DEF are conserved especially in sensor rhodopsin-I, possibly because these helices are needed for interaction with the transducer protein (Htr).

Amino Acid Sequence↗

PubMed1996

Restoration of sensibility in the hand after complete brachial plexus injury.

Twenty-one patients with complete brachial plexus palsy due to the avulsion of multiple cervical nerve roots underwent motor and sensory reconstruction. Of these, 15 patients who had been followed for at least 2 years were included in the present study. Sensory reconstruction was performed by nerve graft or nerve crossing to the median nerve. The donor nerves included the supraclavicular nerve in 10 patients, the intercostal nerve in 3, and the C5 nerve root in the first 2 patients. Limited sensibility in the median nerve distribution of the hand was restored in 12 patients, and the results were classified as S2+ in 2, S2 in 4, S1 in 6, and S0 in 3, according to the S0 to S4 grading system. No moving two-point discrimination was restored in any case. While the best recovery obtained was only at the S2+ level, even this limited sensibility was useful for otherwise completely anesthetic patients.

Adolescent↗

PubMed1996

[Global life satisfaction and its related factors in community elderly residents].

This study was aimed at identifying the distribution of global life satisfaction as measured by Visual Analogue Scale (VAS) and factors related to it in 531 community elderly residents aged 75-80 years. Subjects were divided into two groups according to the extent of their daily activities, which has been emphasized as an important health index for the elderly: the outdoor-activity group (defined as people whose daily activities extended into their community) and the indoor-activity group (defined as people whose daily activities was limited to inside their home). The distribution of global life satisfaction and related factors were compared between the two groups. For independent variables, daily behaviors were classified into five categories and examined for how they related to global life satisfaction. The results obtained were as follows: Global life satisfaction showed a bimodal distribution in both groups tending to be lower in the indoor-activity group than in the outdoor-activity group. Most of the indoor-activity group indicated low or moderate life satisfaction. The extent of their daily activities was thus related to global life satisfaction. The strongest direct factor relating to global life satisfaction was self-rated health for the outdoor-activity group. Some of their daily behaviors also related to it and these significant daily behaviors differed by sex. Only self-rated health was related to global life satisfaction in the indoor-activity group. The results indicate that, when compared to other factors, daily activity in community elderly residents is crucial to increasing their global life satisfaction, and therefore efforts to enlarge subjects' daily activities are also required.

Activities of Daily Living↗

PubMed1995

Expression of the genes for insecticidal crystal proteins in Bacillus thuringiensis: cryIVA, not cryIVB, is transcribed by RNA polymerase containing sigma H and that containing sigma E.

To investigate the mechanism of transcriptional regulation of cryIVA and cryIVB, encoding 130-kDa dipteran-active crystal proteins, in Bacillus thuringiensis subsp. israelensis, we introduced each gene into several sporulation mutants of Bacillus subtilis. A spoIIG mutation, the wild-type gene of which encodes sigma E precursor, completely blocked the cryIVB transcription. In contrast, low but detectable transcription of cryIVA was observed in the spoIIG mutant. In the wild-type B. subtilis, no transcription of cryIVB was detected before T2 (2 h after the onset of stationary phase), while the cryIVA transcription started at the late exponential phase at low levels. Furthermore, in a wild-type strain of B. thuringiensis subsp. israelensis, transcription of cryIVA began earlier than that of genes encoding other crystal components, cryIVB and cytA. A consensus sequence recognized by an RNA polymerase containing sigma H of B. subtilis was found upstream of the transcription start point of cryIVA, which overlapped with that recognized by sigma E.

Bacillus subtilis↗

PubMed1995

Cloning and characterization of a Bacillus thuringiensis homolog of the spoIIID gene from Bacillus subtilis.

The SpoIIID protein of Bacillus subtilis (Bs) is a small DNA-binding protein that is essential for gene expression of the mother cell compartment during sporulation. We have cloned a DNA fragment from Bacillus thuringiensis (Bt) that showed a specific hybridization with the Bs spoIIID gene. Sequence analysis found an open reading frame encoding 90 amino acids (aa), which are 89% identical to the deduced aa sequence of Bs spoIIID. Upstream from the transcription start point (tsp), a nucleotide sequence highly homologous to the consensus sequence motif for the sigma 35-recognized promoters was found. Northern blot analysis has indicated that the expression of the gene is induced only at the midsporulation stage, and that the gene constitutes an operon with a downstream gene, mreB. The Bs strain carrying the spoIIID delta erm or spoIIID83 mutation completely restored sporulation ability upon introduction of the spoIIID homologous gene from Bt. These results strongly suggest that the gene we have cloned is a Bt homolog of spoIIID.

Amino Acid Sequence↗

PubMed1995

Double free-muscle transfer to restore prehension following complete brachial plexus avulsion.

Restoration of finger flexion and extension as well as elbow flexion and extension with a double free-muscle and multiple nerve transfers following complete avulsion of the brachial plexus (nerve roots C5 to T1) is reported. The procedure combines (1) free-muscle transfer with reinnervation by the spinal accessory nerve to achieve elbow flexion and finger extension, (2) free-muscle transfer with reinnervation by the fifth and sixth intercostal nerves to restore finger flexion, (3) third and fourth intercostal motor nerve transfer to the triceps brachi to extend and stabilize the elbow, (4) nerve transfer of the supraclavicular nerve or nerve transfer of the sensory rami of the intercostal nerves to the median nerve to restore hand sensibility, and (5) glenohumeral arthrodesis. Seven of 10 patients recovered elbow function and finger flexion and extension. Five patients reported use of their hand in activities of daily living.

Adolescent↗

PubMed1995

Mouse methyltransferase for repair of O6-methylguanine and O4-methylthymine in DNA.

cDNA for mouse O6-methylguanine-DNA methyltransferase was expressed in methyltransferase-deficient Escherichia coli mutant cells, and the overproduced mouse enzyme was purified to a homogeneous state. Using this purified product, polyclonal antibodies were prepared and used to estimate amounts of the methyltransferase protein in cells. A single cell of NIH3T3 contained 1.8 x 10(4) molecules of the methyltransferase protein. When mouse fibroblasts were immunostained, it was shown that most of the methyltransferase protein exists in the cytoplasm rather than in the nucleus. Using double-stranded oligomers containing a single O6-methylguanine or O4-methylthymine at predetermined sites, the mouse enzyme repaired O6-methylguanine and O4-methylthymine, at an almost equal efficiency. In the LacZ reversion assay, MNNG-induced A:T to G:C as well as G:C to A:T transition mutations were efficiently suppressed by the function of mouse methyltransferase, in vivo.

3T3 Cells↗

PubMed1995

A custom distal femoral prosthesis for reconstruction of large defects following wide excision for sarcoma: results and prognostic factors.

Between 1979 and 1986, 37 patients with sarcoma of the distal femur underwent limb salvage using a custom prosthetic knee replacement. Thirteen (35%) had early complications. Fourteen (38%) had late complications, which consisted of 6 aseptic femoral loosenings, 1 aseptic tibial loosening, 2 tibial fractures, 2 contractures, 1 femoral fracture, 1 prosthetic fracture, and 1 septic loosening. By 1988, nine patients died. Thirteen prostheses failed in 12 patients, resulting in 9 revisions, 2 above-knee amputations, and 2 Van Nes rotationplasties. The 2- and 5-year prosthetic survival rates were 82% and 57%, respectively. Twenty-two of the 26 survivors (85%) had successful limb salvage. Preventable factors were implicated in the loosening of six femoral components and in one femoral fracture. The mean Hospital for Special Surgery Knee Score was 69 (range: 62 to 86).

Adolescent↗

PubMed1995

[Comparison of long-term clinical results of the three models of the Björk-Shiley valve prosthesis and the Omnicarbon valve prosthesis].

A multi-institutional cooperative study, that was a comparison of long-term results of the replacement of the four models of the oblique disc valve prosthesis which had been implanted on aortic and mitral position alone or double from December 1976 to September 1992 in the eight national hospitals in Japan was performed. Seven hundred and thirty-four patients and 765 prostheses that consisted of 582 patients and 610 prostheses of the Björk-Shiley (BS) valve, including 326 patients of the Spherical disc (SP) valve (49 aortic, 259 mitral, and 18 double aortic-mitral), 103 patients of the Convexoconcave disc (CC) valve (45, 51, 7) and 153 patients of the Monostrut (MS) valve (101, 49, 3), and of 152 patients (71, 78, 3) and 155 prostheses of the Omnicarbon (OC) valve were compared with their mortality and morbidity in every valve position respectively according to the approval by STS-guideline. The MS valve and the OC valve showed 0% to 11.3% of operative mortality, 0.3%/py to 1.8%/py of valve related mortality, 85.5% +/- 5.6% to 98.4% +/- 1.6% of actuarial survival rate at 10 years, and 58.5% +/- 6.4% to 82.7% +/- 5.7% of actuarial free rate of all mortality and morbidity at 10 years in every valve position. Structural deteriorations occurred in two patients of the CC valve in the mitral position only, and its rate of all valve positions showed 0.04%/py. Significant differences were seen in actuarial survival rate at 10 years after aortic valve replacement, and in operative mortality rate, improved degree of NYHA class, structural deterioration rate and actuarial free rate of all mortality and morbidity after mitral valve replacement between the group of the MS and OC valve and the group of the SP and CC valve. Therefore the MS valve or the OC valve should be selected to implant rather than the SP valve or the CC valve, and the patient who had been implanted with the CC valve should be treated considering valve position, valve position, valve size, age and activity of the patient and the manufactured date of the prosthesis.

Bioprosthesis↗

PubMed1995

[Serum cardiac troponin-T in coronary artery bypass graft and mitral valve replacement].

Serum cardiac troponin-T was measured to evaluate perioperative myocardial injury in heart surgery. Twelve patients of coronary artery bypass graft (CABG) and nine of mitral valve replacement (MVR) were selected and the measurements were performed at 3 points-before, as well as after the surgery and on the first postoperative day. Elevated serum levels of troponin-T were observed in postoperative measurement in both groups (CABG 2.98 +/- 1.44, MVR 2.57 +/- 0.52 ng.ml-1), where all the preoperative values were less than 0.1 ng.ml-1. On the first postoperative day, CABG group showed a higher serum level of troponin-T than MVR group (6.05 +/- 4.16 vs. 2.57 +/- 2.12 ng.ml-1, P < 0.05 respectively). Taking another myocardial marker, such as CK-MB or myosin light chain I, into consideration, these data indicate that myocardial injury occurs during heart surgery and the grade of injury is severer in CABG than in MVR.

Aged↗

PubMed1994

The novel ion pump rhodopsins from Haloarcula form a family independent from both the bacteriorhodopsin and archaerhodopsin families/tribes.

Extreme halophiles newly collected from Argentine salt flats were characterized, in one of which, Haloarcula (sp. arg-1), light-driven retinal protein ion pumps were found. The proton pump, cruxrhodopsin-1, shows amino acid sequence homologies of 52% to bacteriorhodopsin and 48% to archaerhodopsin-1. The anion pump, cruxhalorhodopsin-1, identified partially as a 394bp polymerase chain reaction product, shows homologies of 70% to halorhodopsin, and 72% to pharaonis halorhodopsin. The ion pumps (and possibly sensors still to be found) in Haloarcula sp. arg-1, which constitute the cruxrhodopsin-1 family, are distinct from the bacteriorhodopsin and the archaerhodopsin families/tribes.

Amino Acid Sequence↗

PubMed1994

Functional analysis of block 5, one of the highly conserved amino acid sequences in the 130-kDa CryIVA protein produced by Bacillus thuringiensis subsp. israelensis.

There are five amino acid sequences highly conserved among Bacillus thuringiensis delta-endotoxins. We have changed the amino acid residues in block 5, one of the conserved sequences, of CryIVA. When the amino acid residues with charged side chains were replaced by others, the amount of production of the altered CryIVA protein was markedly decreased. It is suggested that the decrease is caused by the unstable conformation of the altered CryIVA protein molecule, as judged by digestion with trypsin and thermolysin. On the other hand, the substitution of amino acid residues in block 5 did not affect the insecticidal activity of CryIVA. These results strongly suggest that block 5 of CryIVA is one of the stability-determining elements of the protoxin molecule.

Amino Acid Sequence↗

PubMed1994

Requirement of the Pro-Cys-His-Arg sequence for O6-methylguanine-DNA methyltransferase activity revealed by saturation mutagenesis with negative and positive screening.

O6-Methylguanine-DNA methyltransferase catalyzes transfer of a methyl group from O6-methylguanine and O4-methylthymine of DNA to a cysteine residue of the enzyme protein, thereby repairing the mutagenic and carcinogenic lesions in a single-step reaction. There are highly conserved amino acid sequences around the methyl-accepting cysteine site in eleven molecular species of methyltransferases. To elucidate the significance of the conserved sequence, amino acid substitutions were introduced by site-directed mutagenesis of the cloned DNA for Escherichia coli Ogt methyltransferase, and the activity and stability of mutant forms of the enzyme were examined. When cysteine-139, to which methyl transfer occurs, was replaced by other amino acids, all of the mutants showed the methyltransferase-negative phenotype. Methyltransferase-positive revertants, isolated from one of the negative mutants, had restored codons for cysteine. Thus the cysteine residue is essential for acceptance of the methyl group and is not replaceable by other amino acids. Using this negative and positive selection procedure, the analysis was extended to other residues near the acceptor site. At the histidine-140 and arginine-141 sites, all the positive revertants isolated carried codons for amino acids identical to those of the wild-type protein. At proline-138, five substitutions (serine, glutamine, threonine, histidine, and alanine) exhibited the positive phenotype but levels of methyltransferase activity in extracts of cells harboring these mutant forms were very low. This suggests that the proline residue at this site is important for maintaining the proper conformation of the protein. With valine-142 substitutions there were seven types of positive revertants, among which mutants carrying isoleucine, cysteine, leucine, and alanine showed relatively high levels of methyltransferase activity. These results indicate that the sequence Pro-Cys-His-Arg is a sine qua non for methyltransferase to exert its function.

Alkylating Agents↗