Biomedical subjects

Y Higuchi

Publications and source records attributed to Y Higuchi.

At least 91 records · Page 5Linked to original sources

PubMed1999

Structure determination of rubredoxin from Desulfovibrio vulgaris Miyazaki F in two crystal forms.

The structures of two crystal forms (form I, P3221, a = b = 43.7, c = 50.7 A; form II, P21, a = 27.3, b = 44.9, c = 51.2 A and beta = 90. 6 degrees ) of the rubredoxin from Desulfovibrio vulgaris Miyazaki F have been solved by the molecular-replacement method. Form I has been refined at a resolution of 2.0 A to an R value of 20.8% and includes 32 water molecules. Form II includes 86 water molecules and has been refined at 1.9 A resolution to an R value of 17.5%. In form II, there are three molecules in the asymmetric unit with the molecules related by a non-crystallographic 32 symmetry axis. In both crystal forms, it was found that only a few residues effectively participate in the formation of intermolecular contacts along both the crystallographic (form I) and the non-crystallographic (form II) 32 axes. The crystal structure of the form II crystal is compared with those of other rubredoxin molecules from anaerobic bacteria. From this comparison, a similarity in the core region, which is composed of aromatic residues and includes the active centre, has been revealed.

Amino Acid Sequence↗

PubMed1999

Crystallization and preliminary x-ray study of two crystal forms of Klebsiella oxytoca diol dehydratase-cyanocobalamin complex.

Two crystal forms of Klebsiella oxytoca diol dehydratase complexed with cyanocobalamin have been obtained and preliminary crystallographic experiments have been performed. The crystals belong to two different space groups, depending on the crystallization conditions. One crystal (form I) belongs to space group P212121 with unit-cell parameters a = 76.2, b = 122.3, c = 209. 6 A, and diffracts to 2.2 A resolution using an X-ray beam from a synchrotron radiation source. The other crystal (form II) belongs to space group P21 with unit-cell parameters a = 75.4, b = 132.7, c = 298.8 A, beta = 91.9 degrees, and diffracts to 3.0 A resolution. For the purpose of structure determination, a heavy-atom derivative search was carried out and some mercuric derivatives were found to be promising. Structure analysis by the multiple isomorphous replacement method is now under way.

Bacterial Proteins↗

PubMed1999

Crystallization and preliminary crystallographic studies of FMN-binding protein from Desulfovibrio vulgaris miyazaki F.

The flavin mononucleotide binding protein from Desulfovibrio vulgaris (Miyazaki F) was crystallized using the vapour-diffusion method. The crystal belongs to the monoclinic space group P21 with unit-cell parameters a = 37.2, b = 84.6, c = 41.1 A, beta = 94.1 degrees, contains two molecules per asymmetric unit and diffracts beyond 1.2 A resolution with a synchrotron radiation X-ray source.

Bacterial Proteins↗

PubMed1999

Benign familial neonatal convulsions followed by benign epilepsy with centrotemporal spikes in two siblings.

PURPOSE: To report on sibling cases with benign familial neonatal convulsions (BFNC) followed by benign epilepsy with centrotemporal spikes (BECT). METHODS: Case histories and EEGs were obtained for the two siblings with neonatal and subsequent epileptic seizures in one pedigree with BFNC. RESULTS: The family included six affected cases of BFNC in two generations: the proband, the proband's mother and two sisters, and the proband's maternal uncle and his daughter. The proband developed a generalized tonic convulsion 2 days after birth with no apparent cause and normal interictal EEG, and experienced a total of 18 episodes of tonic or clonic seizures or both by age 9 months. In the follow-up course, an EEG recording showed rolandic discharges at 2 years, and a sylvian seizure occurred at 4 years during sleep. On carbamazepine therapy, the last seizure was recorded at 9 years after a total of 11 episodes of sylvian seizures, with normal EEGs after 12 years. The proband's sister experienced nine episodes of brief tonic seizures between 7 and 9 days after birth, and also developed eight episodes of sylvian seizures from 4 to 7 years, with rolandic discharges on EEG until age 9 years. All of the family members had normal psychomotor development, with no neurologic sequelae. CONCLUSIONS: This report of BFNC followed by BECT in sibling cases is significant in view of the genetic analysis and the classification of epilepsies and epileptic syndromes.

Age of Onset↗

PubMed1999

An investigation of the disabled elderly in a geriatric health services facility in an urban area of Japan and attitudes of their family caregiver.

We investigated characteristics of 72 clients in a geriatric health services facility (hereafter called GHSF), conditions of their family caregivers, and the factors associated with the caregivers choice of discharge destination. Most of the clients were elderly females with a low degree of independence, and dementia was observed in about 60% of them. The clients had children, but many of them lived alone before admission to the GHSF. The rate of admission from hospitals was high (54%), and that of discharge to hospitals was also high (50%). Sixty-seven percent of the clients stayed in for a period of over six months. Most of the family caregivers were daughters or daughters-in-law, and considered themselves to be healthy. Sixty-three percent of them had jobs, and most of the caregivers had no sub-caregiver to assist them. The family caregivers desired the client's home (19.4%), hospital or another GHSF (54.2%), or nursing home (26.4%) as the discharge destination from the GHSF. According to Hayashi's quantification theory type II, the factors related to the home as the discharge destination desired by client's family caregivers are as follows; caregivers used formal home public health nursing visit service before entering the GHSF, the job of the caregiver was a part-time job, the client did not show dementia, the period of care experience was shorter than one year.

Aged↗

PubMed1999

Effects of continuous infusion of PTH on experimental tooth movement in rats.

Development of new methods for accelerating orthodontic tooth movement has been strongly desired for shortening of the treatment period. The rate of orthodontic tooth movement is dependent on the rate of bone resorption occurring in the compressed periodontium in the direction of orthodontic force applied to the tooth. In the present study, we examined the effects of continuous infusion of parathyroid hormone (PTH) on tooth movement. Male rats weighing 350-400 g were treated with subcutaneous of vehicle or hPTH(1-84) at 1-10 micrograms/100 g of body weight/day. When the upper right first molar (M1) was moved mesially for 72 h by the insertion of an elastic band between the first and second molars, M1 movement was accelerated by PTH infusion at 10 micrograms. PTH infusion caused a 2- to 3-fold increase in the number of osteoclasts in the compressed periodontium of M1, indicating that such treatment accelerated tooth movement by enhancing bone resorptive activity induced in the compressed periodontium. When M1 was moved mesially by an orthodontic coil spring ligated between upper incisors and M1 for 12 days, PTH(1-84) infusion at 10 micrograms caused a 2-fold increase in the rate of M1 movement. PTH(1-34) infusion at 4 micrograms had an effect comparable to that of PTH(1-84). However, intermittent injection of PTH(1-34) did not accelerate M1 movement. PTH infusion for 13 days did not affect either bone mineral measurements or the serum calcium level. These findings suggest that continuous administration of PTH is applicable to accelerate orthodontic tooth movement.

Animals↗

PubMed1999

Enhancement of XPG mRNA transcription by human interferon-beta in Cockayne syndrome cells with complementation group B.

Human interferon-beta (HuIFN-beta) confers UV-refractoriness in association with increased DNA repair capacity to human cells. We examined the modulation of XPG gene expression by HuIFN-beta in UV-sensitive cells from Cockayne syndrome complementation B (CSB), xeroderma pigmentosum complementation A (XPA) and normal control cells. Northern blot analysis revealed that XPG mRNA was more extensively transcribed in CSB cells treated with HuIFN-beta than in those without HuIFN-beta treatment. XPG mRNA from XPA cells and normal control cells was not markedly transcribed by HuIFN-beta treatment compared to that from CSB cells. The findings suggested that different mechanisms of UV-refractoriness by HuIFN-beta exist between CS and XP.

Blotting, Northern↗

PubMed1999

Fibrinogen Matsumoto III: a variant with gamma275 Arg-->Cys (CGC-->TGC)--comparison of fibrin polymerization properties with those of Matsumoto I (gamma364 Asp-->His) and Matsumoto II (gamma308 Asn-->Lys).

Fibrinogen Matsumoto III (M-III) is a dysfibrinogen identified in a 66-year-old woman with rectal cancer. The fibrinogen level determined by the thrombin-time method was markedly decreased in preoperative coagulation tests of her plasma. Three fibrinogen polypeptide-chain gene fragments from the proposita were amplified by the polymerase chain reaction method, then sequenced. The triplet CGC encoding the amino acid residue gamma275 was replaced by TGC, resulting in the substitution of Arg->Cys. There have been previous reports of nine families with the same alteration, nine families with an Arg->His variant and one family with an Arg->Ser variant in this residue, which has been shown to be one of the most important amino acids in the 'D:D' interaction site. In addition, there are three silent mutations in the Aalpha-chain gene and two mutations in the intron of the Bbeta-chain and the gamma-chain gene. However, none of these mutations is thought to be the cause of the dysfunctional fibrinogen. The thrombin-catalyzed fibrin polymerization in the presence of 1 mM Ca ions was markedly delayed in purified M-III. Its lag period was longer than those of Matsumoto II (M-II; gamma308Asn->Lys) and Matsumoto I (M-I; gamma364Asp-His). gamma364Asp is one of the most important residues in the polymerization pocket of the 'D:E' interaction site and gamma308Asn is located in the vicinity of a high affinity Ca2+ binding site in the D-domain, gamma311-336. The maximum slope of the polymerization curve for M-III was about 4-fold steeper than that for M-1 but less steep than that for M-II. These results may suggest that the tertiary structure of the polymerization pocket plays a more important role in the lateral aggregation of protofibrils than that of the 'D:D' interaction site.

Aged↗

PubMed1999

[A case positive for the inhibitor for coagulation factor V].

We report a 71-year-old man who exhibited hepatocellular carcinoma and the inhibitor for coagulation factor V (FV). The inhibitor was found when his coagulation screening tests revealed an abnormally prolonged prothrombin time (71.1 sec) and activated partial thromboplastin time (more than 120 sec) but normal values of fibrinogen (241 mg/dl), the thrombo test (84%) and hepaplastin test (71%). In addition, FV-coagulation activity of the patient's plasma showed less than 1% of the pooled normal plasma and inhibitory activity for FV of his plasma was 32 Bethesda units. This inhibitory activity was neutralized by the addition of anti-human immunoglobulin-gamma-chain serum. The patient was treated with a fibrin sealant including human thrombin when he underwent an partial hepatectomy (32 months before onset) and received 2 doses of thrombin orally (5 months and 2 weeks before onset) to stop bleeding from phlebeurysm. Several studies have reported that the inhibitor for FV was produced after treatment with bovine thrombin containing FV as a contaminant. These findings suggest that our patient may produce an immunoglobulin specific for FV after similar stimulation of human thrombin containing FV.

Aged↗

PubMed1998

Basis for monomer stabilization in Rhodopseudomonas palustris cytochrome c' derived from the crystal structure.

The crystal structure of an unusual monomeric cytochrome c' from Rhodopseudomonas palustris (RPCP) has been determined at 2.3 A resolution. RPCP has the four-helix (helices A, B, C and D) bundle structure similar to dimeric cytochromes c'. However the amino acid composition of the surface of helices A and B in RPCP is remarkably different from that of the dimeric cytochromes c'. This surface forms the dimer interface in the latter proteins. RPCP has seven charged residues on this surface contrary to the dimeric cytochromes c', which have only two or three charged groups on the corresponding surface. Moreover, hydrophobic residues on this surface of RPCP are two to three times fewer than in dimeric cytochromes c'. As a result of the difference in amino acid composition, the A-B surface of RPCP is rather hydrophilic compared with dimeric cytochromes c'. We thus suggest that RPCP is monomeric in solution because of the hydrophilic nature of the A-B surface. The amino acid composition of the A-B surface is similar to that of Rhodobacter capsulatus cytochrome c' (RCCP), which is an equilibrium admixture of monomer and dimer. The charge distribution of the A-B surface in RCCP, however, is considerably different from that of RPCP. Due to the difference, RCCP can form dimers by both ionic and hydrophobic interactions. These dimers are quite different from those in proteins which form strong dimers such as in Chromatium vinosum, Rhodospirillum rubrum, Rhodospirillum molischianum and Alcaligenes. Cytochrome c' can be classified into two types. Type 1 cytochromes c' have hydrophobic A-B surfaces and they are globular. The A-B surface of type 2 cytochromes c' is hydrophilic and they take a monomeric or flattened dimeric form.

Amino Acid Sequence↗

PubMed1998

Estimation of shunt flow in coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin.

The shunt flow from the coronary artery to pulmonary arteries was evaluated in 6 patients with coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin. In 2 patients, whose degree of visualization of pulmonary arteries by coronary angiography was relatively high, lung perfusion scintigrams demonstrated the defects at the distal of coronary-pulmonary fistulas.

Aged↗

PubMed1998

Crystallization and preliminary X-ray diffraction study of lactonohydrolase from Fusarium oxysporum.

The lactonohydrolase from the fungus Fusarium oxysporum AKU 3702 was crystallized by the vapour-diffusion procedure in the presence of polyethylene glycol 4000 as a precipitant. The crystals belong to the monoclinic space group P21 with unit-cell parameters a = 156, b = 100, c = 94.1 A, beta = 91.7 degrees. Assuming that there are two lactonohydrolase-dimer molecules in the asymmetric unit, the crystal volume per unit molecular mass, Vm, is calculated to be 2.94 A3 Da-1.

Carboxylic Ester Hydrolases↗

PubMed1998

Search for genes involved in UV-resistance in human cells by mRNA differential display: increased transcriptional expression of nucleophosmin and T-plastin genes in association with the resistance.

UVr-10 UV-resistant cells were established from UV-sensitive human RSb cells. We searched here for genes expressed differentially between UVr-10 and RSb cells using a differential display method to elucidate the molecular mechanisms underlying the UV-resistance. Thirteen candidate cDNA fragments were obtained from 514 mRNA species first screened. Among the cDNA fragments, 3 revealed increased mRNA expression in UVr-10 cells compared with RSb cells by Northern analysis. Nucleotide sequence analysis identified 2 of the 3 cDNA fragments as encoding nucleophosmin (NPM) and T-plastin. The expression of NPM mRNA was induced after UV irradiation in UVr-10 cells but not in RSb cells, whereas irradiation did not affect the expression of T-plastin mRNA. UVr-10 cells transfected with antisense cDNA for NPM mRNA were partially sensitized to UV cell-killing. Thus, NPM and possibly T-plastin genes may contribute to the increased resistance to UV cell-killing, at least in the human cells tested.

Base Sequence↗

PubMed1998

Living-related liver transplantation and neurological outcome in children with fulminant hepatic failure.

BACKGROUND: Fulminant hepatic failure (FHF) in children is associated with high mortality under medical management. Living-related liver transplantation (LRLT) is an accepted measure to treat the children with end-stage liver disease. Reversibility of hepatic encephalopathy is crucial for the quality of life among the survivors after transplantation. METHODS: A retrospective review was made of the records of children undergoing LRLT at this hospital between May 1992 and November 1996. RESULTS: Eleven children with FHF underwent emergency LRLT. The mean age was 5 years (range, 2 months to 15 years). The indication for transplantation was persistent or worsening hepatic encephalopathy and severe coagulopathy, despite repeated plasma exchanges or exchange transfusions. The cause of FHF was non-A, non-B hepatitis in seven children, hepatitis B in two children, herpes simplex virus hepatitis in one child, and fulminant Wilson's disease with intravascular hemolysis in one child. The grade of hepatic encephalopathy was II in four children, III in two, and IV in five. The actuarial survival rate was 73% after a mean follow-up of 28 months (range, 13-67 months). Short-term neurological morbidity was present in two children with grade IV encephalopathy who also showed brain edema on cranial computed tomography. Eight survivors exhibited no long-term neurological deficit; the mean intelligence or developmental quotient was 97 (range, 86-110) at the end of the follow-up period. CONCLUSIONS: LRLT is an effective option for the treatment of FHF in children. The long-term neurological status is satisfactory among survivors.

Brain Edema↗

PubMed1998

Bone morphogenetic protein signaling is required for maintenance of differentiated phenotype, control of proliferation, and hypertrophy in chondrocytes.

To examine the role of bone morphogenetic protein (BMP) signaling in chondrocytes during endochondral ossification, the dominant negative (DN) forms of BMP receptors were introduced into immature and mature chondrocytes isolated from lower and upper portions of chick embryo sternum, respectively. We found that control sternal chondrocyte populations expressed type IA, IB, and II BMP receptors as well as BMP-4 and -7. Expression of a DN-type II BMP receptor (termed DN-BMPR-II) in immature lower sternal (LS) chondrocytes led to a loss of differentiated functions; compared with control cells, the DN-BMPR- II-expressing LS chondrocytes proliferated more rapidly, acquired a fibroblastic morphology, showed little expression of type II collagen and aggrecan genes, and upregulated type I collagen gene expression. Expression of DN-BMPR-II in mature hypertrophic upper sternal (US) chondrocytes caused similar effects. In addition, the DN-BMPR-II-expressing US cells exhibited little alkaline phosphatase activity and type X collagen gene expression, while the control US cells produced both alkaline phosphatase and type X collagen. Both DN-BMPR-II-expressing US and LS chondrocytes failed to respond to treatment with BMP-2 . When we examined the effects of DN forms of types IA and IB BMP receptors, we found that DN-BMPR-IA had little effect, while DN-BMPR-IB had similar but weaker effects compared with those of DN-BMPR-II. We conclude that BMP signaling, particularly that mediated by the type II BMP receptor, is required for maintenance of the differentiated phenotype, control of cell proliferation, and expression of hypertrophic phenotype.

Animals↗

PubMed1998

Increase in nitric oxide in the hypoxic-ischemic neonatal rat brain and suppression by 7-nitroindazole and aminoguanidine.

We measured the changes in nitric oxide (NO) metabolites in the brains of neonatal rats with hypoxic-ischemic damage. There were two peaks of NO metabolites in the lesioned side of the cortex without treatment: one during hypoxia and the other during the re-oxygenation period. Prehypoxic treatment with 7-nitroindazole, a selective neuronal NO synthase inhibitor, suppressed both peaks of NO metabolites, whereas prehypoxic treatment with aminoguanidine, a selective inducible NO synthase inhibitor, partially suppressed only the peak in the re-oxygenation period. These data suggest different roles of neuronal and inducible NO synthases in the pathogenesis of hypoxic-ischemic encephalopathy.

Animals↗

PubMed1998

Small spot sign of rectal carcinoma by endorectal ultrasonography: histologic relation and clinical impact on postoperative recurrence.

PURPOSE: We observed small spots at the margin of rectal carcinomas on endorectal ultrasonography. Our aim was to study the relationship between ultrasonographic evidence of these spots and histologic characteristics of disease and postoperative recurrence. PATIENTS AND METHODS: The study group comprised 55 patients, 36 men and 19 women, with rectal carcinoma as confirmed by biopsy. The patients were followed up at three-month intervals for six months to three years and six months after the operation. Endorectal ultrasonography was performed in the usual manner. Surgically resected specimens were stained with hematoxylin and eosin and histologically examined. Vessel invasion was graded from 0 (not invasive) to 3 (most invasive). RESULTS: Among the 55 patients studied, 3 had Stage T2,N0,M0 rectal carcinomas and 35 had Stage T3,N0,M0 carcinomas, 5 (14.3 percent) of whom had echographic evidence of small spots. Thirteen patients had Stage T3,N1/2,M0 carcinomas, comprising 12 (92.3 percent) with small spots, and four patients had T3,N1/2,M1 carcinomas, all with small spots. Vessel invasion of Grade 2 or higher was observed around the carcinomas in 20 of 21 patients who had small spots. Ten of 13 patients with many spots at the margin of the carcinoma (a spot grade of ++) histologically had marked venous or lymphatic invasion (an invasion Grade 3). The presence of small spots was closely associated with massive venous or lymphatic invasion (a vessel invasion grade of 2 or more). Four patients had synchronous liver metastases, and small spots were found in all four. Distant metastases and local recurrence were found in 11 of 21 patients with small spots. We found no recurrence in any patient without small spots on endorectal ultrasonography. CONCLUSIONS: Small spots indicate the presence of massive venous or lymphatic invasion and a high risk of postoperative recurrence.

Aged↗

PubMed1998

Limitation of endorectal ultrasonography: what does a low lesion more than 5 mm in size correspond to histologically?

PURPOSE: The accuracy of diagnosis of metastatic lymph nodes for rectal carcinoma has not improved. A low echoic lesion more than 5 mm in size detected by endorectal ultrasonography is preoperatively assessed as a metastatic lymph node. What does a low echoic lesion more than 5 mm in size correspond to histologically? METHODS: Forty-seven patients with lower rectal carcinoma (Term I, 1986-1990) and 48 patients with lower rectal carcinoma (Term II, 1991-1995) undergoing endorectal ultrasonography were reviewed. Surgically resected rectal specimens from 40 patients with rectal carcinoma underwent ultrasonography. Low echoic lesions more than 5 mm in size were taken from resected specimens and were stained with hematoxylin, followed by histologic examination. RESULTS: The accuracy of diagnosis of metastatic lymph nodes of Term II was not higher than that of Term I. Twenty-five low echoic lesions were detected by ultrasonography using 40 resected specimens. Seventeen of these 25 lesions (68 percent) were histologically confirmed to be metastatic lymph nodes. One of 25 (4 percent) was found to be lymphadenitis with no metastasis. Among the 25 lesions, 5 (20 percent) were histologically confirmed to be tumor deposits, 2 (8 percent) fatty tissue, and 22 (88 percent) carcinoma. CONCLUSIONS: Low echoic lesions were histologically confirmed to be tumor deposits (20 percent) and metastatic lymph nodes (68 percent). Although these data show deficiencies and limitations of the accuracy of endorectal ultrasonography, they compare favorably with other series, and no other current technology can show similar accuracy.

Endosonography↗