Biomedical subjects
Publications and source records attributed to H Shimizu.
Aortic intramural hemorrhage occurs fairly frequently among patients with aortic dissection, and may not have a poor prognosis if it is Stanford type B. In patients with type A aortic dissection, cardiac tamponade should be ruled out during observation.
Fungal nitric-oxide reductase (NOR) is a heme enzyme that catalyzes the reduction of NO to N(2)O through its ferric-NO complex, the first intermediate of the catalysis. Crystal structures of the ferric-NO forms of wild type (WT) fungal NOR, and of the Ser(286) --> Val and Ser(286) --> Thr mutant enzymes were determined to 1.7-A resolution at cryogenic temperature (100 K). This shows a slightly tilted and bent NO binding to the heme iron, in sharp contrast to the highly bent NO coordination found in ferrous hemoproteins. In the WT structure, a specific hydrogen-bonding network that connects the active site to the solvent was identified, H(2)O(Wat(74))-Ser(286)-H(2)O(Wat(33))-Asp(393)-solvent. Wat(74) is located 3.10 A from the iron-bound NO. Replacement of Ser(286) with Val or Thr scarcely alters the NO coordination structure but expels the water molecules, Wat(74) from the active site. The Asp(393) mutation does not influence the position of Wat(74), but disrupts the hydrogen-bonding network at Wat(33), as evidenced by enzymatic, kinetic, and spectroscopic (resonance Raman and IR) results. The structural changes observed upon the Ser(286) or the Asp(393) mutation are consistent with the dramatic loss of the enzymatic activity for the NO reduction of fungal NOR. We have conclusively identified the water molecule, Wat(74), adjacent to the iron-bound NO as a proton donor to the Fe-NO moiety. In addition, we find the hydrogen-bonding network, H(2)O(Wat(74))-Ser(286)-H(2)O(Wat(33))-Asp(393), as a proton delivery pathway in the NO reduction reaction by fungal NOR.
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We have reported the presence of continuous gamma (30-150 Hz) activity in the human medial temporal lobe (MTL). Since the MTL is involved in learning and memory, we speculated that MTL gamma activity is related to such higher brain functions. It is thus of interest to learn how this activity changes during different states of consciousness. In this study, we recorded electrocorticographic (ECoG) activity directly from the surface of the MTL after various doses of sevoflurane anesthesia. Five epileptic patients underwent electrode placement operations in which electrodes were attached to the surfaces of the MTL and the basal temporal lobe (BTL). Immediately following the operation ECoG was recorded from each patient under four concentrations of sevoflurane anesthesia (1.5, 2.0, 2.5 and 3.0%). Fast Fourier Transform (FFT) analysis was performed on the MTL ECoGs. Under the lowest sevoflurane concentration, MTL gamma activity was observed in all patients. However, gamma activity was progressively suppressed by increased concentrations of sevoflurane, in a dose-dependent manner. Sevoflurane has been known to reduce neuronal excitability in the rat hippocampus in vitro, probably by changing GABAergic inhibition. The reduction of MTL gamma in the present study may be the result of such a mechanism. Although memory function was not tested in this study, the amount of MTL gamma activity may be related to residual memory function during anesthesia.
The NS3 protein of Japanese encephalitis virus (JEV) contains motifs typical of RNA helicase/NTPase but no RNA helicase activity has been reported for this protein. To identify and characterize the RNA helicase activity of JEV NS3, a truncated form of the protein with a His-tag was expressed in Escherichia coli and purified. The purified JEV NS3 protein showed an RNA helicase activity, which was dependent on divalent cations and ATP. An Asp-285-to-Ala substitution in motif II of the JEV NS3 protein abolished the ATPase and RNA helicase activities. These results indicate that the C-terminal 457 residues are sufficient to exhibit the RNA helicase activity of JEV NS3.
The distributions of class III alcohol dehydrogenase (ADH), a glutathione-dependent formaldehyde dehydrogenase, and class I ADH in the human brain were examined immunohistochemically. The most intense immunostaining of class III ADH was observed in the dendrites and cytoplasm of cerebellar Purkinje cells. Scattered cerebral cortical neurons in layers IV and V, and some hippocampal pyramidal neurons were also immunopositive. The neuronal distribution of class III ADH resembled that of the vulnerable neurons in patients with hypoxic encephalopathy, which in view of the intense staining in the Purkinje cells, raises the possibility that this enzyme contributes to the hypoxia and cerebellar degeneration suffered by chronic alcoholics. Perivascular and subependymal astrocytes, which contribute to the maintenance of the cerebral cellular milieu and isolate the brain from the systemic circulation and cerebrospinal fluid, were also class III ADH positive. As the substrates of this enzyme include intrinsic toxic formaldehyde, inflammatory intermediate of 20-hydroxy-leukoteiene B4, and possibly ethanol, the distribution of class III ADH immunostaining indicates this enzyme contributes to the defence of the brain against degenerative processes. The finding that, unlike ependymal cells, subependymal astrocytes were class III ADH positive, suggests this enzyme may be useful for differentiating astrocytes and ependymal cells.
X-linked ichthyosis (XLI) is an inherited skin disorder due to deficiency of steroid sulfatase (STS) activity. XLI has been diagnosed by assaying STS activity in placenta or lymphocytes of patients after birth. Most patients have a large deletion of the STS gene, generated by inaccurate recombination at the STS locus. However, point mutations in the STS gene have been reported in some patients with complete STS deficiency. In a new case of STS deficiency, we identified an STS missense mutation, Glu560Pro or E560P. This new point mutation suggests that the C-terminal region of the STS enzyme is important for STS enzymatic function. Hum Mutat 15:296, 2000.
To clarify the relationship of gap junction formation to phosphorylation of connexin43 (Cx43) in mouse preimplantation embryos, immunofluorescence and Western blot analysis were conducted. Immunofluorescence showed Cx43 positive spots first at the mid-eight-cell stage (6 hr postdivision to the eight-cell stage). The number of spots increased from 6 to 15 hr postdivision to the eight-cell stage. Western blot analysis suggested Cx43 to possibly be present in the nonphosphorylated form at the mid-four-cell stage (6 hr postdivision to the four-cell stage), and phosphorylated Cx43 to increase from the mid-eight-cell stage (6 hr post-division to the eight-cell stage) onward. Dibutyryl cAMP (dbcAMP), a protein kinase A (PKA) activator, added to the culture medium increased the phosphorylation of Cx43 and Cx43 positive spots. The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC) activator, increased the phosphorylation of Cx43, but decreased Cx43 positive spots. These results suggest that the phosphorylation of Cx43, induced by different protein kinase, leads to a different effect on gap junction formation in mouse preimplantation embryos.
BACKGROUND: The relationship between the severity of chronic-phase stenosis of infarct-related lesions (IRLs) and chronic left ventricular function in anterior acute myocardial infarctions (AMI) has not been adequately investigated. HYPOTHESIS: This study investigated whether ST elevation in lead aVL of admission electrocardiogram (ECG) would be a determinant factor of the relationship between the severity of stenosis of the IRL and chronic left ventricular function after anterior wall AMI. METHODS: One month after AMI, the IRL was evaluated by coronary angiography in 98 patients with anterior AMI, and left ventricular ejection fraction (LVEF) was determined using multigated radionuclide angiocardiography. Patients were classified according to the severity of the IRL: patients with 100% occlusion (Group O), patients with 90 to 99% stenosis (Group H), and patients with < or =75% stenosis (Group L). Patients with ST elevation > or =0.1 mV in the aVL lead on their admission ECG were included in the ST-elevation group, and those with ST elevation <0.1 mV were included in the non-ST-elevation group. RESULTS: The LVEF was greater in the non-ST-elevation group than in the ST-elevation group (p<0.0001), and the LVEF in a whole group as follows: Group L LVEF>Group H LVEF>Group O LVEF (p = 0.0160). In the ST-elevation group, LVEF was higher in Group L than in the other groups (p = 0.0251). There were three independent predictors of a reduced LVEF: ST-elevation in aVL [odds ratio (OR): 3.38, p = 0.0044], IRL stenosis > or =90% (OR: 2.90, p = 0.0044), and the IRL occurring in the left anterior descending artery proximal to the first diagonal branch (OR: 6.31, p = 0.0024). CONCLUSION: Left ventricular function was preserved, regardless of the severity of residual stenosis, in patients without ST elevation in aVL if the IRL was not totally occluded. In patients with ST elevation in aVL, LVEF was lower in patients with more severe stenosis, even if the IRL was patent.
Large volumes of data are routinely collected during bioprocess operations and, more recently, in basic biological research using genomics-based technologies. While these data often lack sufficient detail to be used for mechanism identification, it is possible that the underlying mechanisms affecting cell phenotype or process outcome are reflected as specific patterns in the overall or temporal sensor logs. This raises the possibility of identifying outcome-specific fingerprints that can be used for process or phenotype classification and the identification of discriminating characteristics, such as specific genes or process variables. The aim of this work is to provide a systematic approach to identifying and modeling patterns in historical records and using this information for process classification. This approach differs from others in that emphasis is placed on analyzing the data structure first and thereby extracting potentially relevant features prior to model creation. The initial step in this overall approach is to first identify the discriminating features of the relevant measurements and time windows, which can then be subsequently used to discriminate among different classes of process behavior. This is achieved via a mean hypothesis testing algorithm. Next, the homogeneity of the multivariate data in each class is explored via a novel cluster analysis technique called PC1 Time Series Clustering to ensure that the data subsets used accurately reflect the variability displayed in the historical records. This will be the topic of the second paper in this series. We present here the method for identifying discriminating features in data via mean hypothesis testing along with results from the analysis of case studies from industrial fermentations
An important step in data analysis is class assignment which is usually done on the basis of a macroscopic phenotypic or bioprocess characteristic, such as high vs low growth, healthy vs diseased state, or high vs. low productivity. Unfortunately, such an assignment may lump together samples, which when derived from a more detailed phenotypic or bioprocess description are dissimilar, giving rise to models of lower quality and predictive power. In this paper we present a clustering algorithm for data preprocessing which involves the identification of fundamentally similar lots on the basis of the extent of similarity among the system variables. The algorithm combines aspects of cluster analysis and principal component analysis by applying agglomerative clustering methods to the first principal component of the system data matrix. As part of a rational strategy for developing empirical models, this technique selects lots (samples) which are most appropriate for inclusion in a training set by analyzing multivariate data homogeneity. Samples with similar data structures are identified and grouped together into distinct clusters. This knowledge is used in the formation of potential training sets. Additionally, this technique can identify atypical lots, i.e., samples that are not simply outliers but exhibit the general properties of one class but have been given the assignment of the other. The method is presented along with examples from its application to fermentation data sets.
BACKGROUND: The hypocholesterolemic effect of soy protein concentrates on normolipidemic subjects still remains unclear. Our objective is to assess the effect of soymilk supplementation, a whole soy product, with usual diet on serum lipids in normolipidemic subjects. METHODS: We conducted a randomized controlled trial on 60 premenopausal normolipidemic Japanese women. After excluding 8 subjects whose initial serum concentration of total cholesterol or triacylglycerol was higher than 220 mg/dL (5.69 mmol/L) or 160 mg/dL (1.81 mmol/L), respectively, we encouraged the subjects in the soymilk-supplemented group (n = 27) to consume 400 mL (408 g) of commercial regular soymilk daily during two menstrual cycles. There were no significant differences in variables, including nutrient intake, between the soymilk-supplemented and control (n = 25) groups before the intervention. RESULTS: After the trial, we observed a significant decrease of 10.9 mg/dL, or 5.3%, in serum concentration of total cholesterol in the soymilk-supplemented group. During the intervention, nutrient intake assessment showed significant increases in nutrient densities of vitamin E, polyunsaturated fatty acids, isoflavones, and P/S ratio and decreases in total energy and nutrient densities of vitamin C and green tea in this group. A statistically significant decrease in serum total cholesterol could still be observed even after excluding the estimated hypocholesterolemic effects of soymilk's polyunsaturated fatty acids. CONCLUSIONS: Our results suggest the hypocholesterolemic effect of soymilk, a traditional whole soy product, in Asian countries in normolipidemic subjects.
Eleven cases with mucinous noncystic carcinoma (MC) of the pancreas were studied by histology and mucin immunohistochemistry, to elucidate the mechanism, or route of development, and pre-existing histological type of MC of the pancreas. These MCs were observed in close approximation to, or surrounding, intraductal papillary-mucinous carcinomas (IPMCs), and were centrally situated among ductal adenocarcinomas (DAs). Hence, the 11 cases originated from 8 IPMCs and 3 DAs. The mechanism and routes to MC were divided into four types as follows: IPMC directly invaded the stroma (4 cases), over-production of mucin in IPMC expanded the branches of the pancreatic duct possibly resulting in rupture (3 cases), DA underwent extreme mucinous degeneration (3 cases), and a recurrent form, as MC, at the surgical stump of IPMC (one case). The outcomes of MC cases with IPMC had variable survival rates, while those from DA had short durations. MUC immunoreactivity in MC was divided into three categories; anti-MUC1-positive only (2 IPMCs, 2 DAs), mixed anti-MUC1 and anti-MUC2-positive (3 IPMCs, one DA) and anti-MUC-positive only (3 IPMCs). Pre-existing MC histological types included both IPMC and DA. These two pre-existing types of MC involved mucin overproduction and mucinous degeneration. MUC immunoreactivity in MC revealed three patterns, which may be related to variable outcomes.
OBJECTIVE: Allogenic blood transfusion can transmit viral infection or cause immunological side effects. Recently, improved operative techniques have required less frequent transfusions in thoracic aortic aneurysm surgery. This study examined the efficacy of using autologous platelet-rich plasma in thoracic aortic aneurysm surgery. METHOD: Eight patients underwent nine operations using an autologous platelet-rich plasma program. The control group consisted of 15 historic patients matched for operative procedure and age. All operations were performed by the same surgeon. The platelet-rich plasma program required the collection of platelet-rich plasma prior to the infusion of heparin; platelet-rich plasma transfusions were administered following neutralization by heparin. RESULTS: The volume of platelet-rich plasma averaged 252 +/- 14.3 ml; total platelets in the platelet-rich plasma were 2.27 +/- 0.20 x 10(11) cells. The median number of homologous red blood cells transfused during the operative day was 0 units (range 0 to 12) in the platelet-rich plasma group and 3 units (range 0 to 25) in the controls. The median number of homologous fresh frozen plasma was 0 units (range 0 to 20) in the platelet-rich plasma group, and 5 units (range 0 to 30) in the controls. The platelet-rich plasma group received significantly fewer transfusions. CONCLUSION: Autologous platelet-rich plasma transfusion was an effective way to reduce homologous blood transfusions in thoracic aortic aneurysm surgery.
Treatment of patients with acute cerebral ischaemic events remains controversial. We investigated the reversibility of high signal intensity on diffusion-weighted (DW) MRI after acute local intra-arterial fibrinolysis (LIF) and the feasibility of DW MRI for selecting patients for acute LIF. Nine patients with acute middle cerebral artery embolic occlusion underwent single-photon emission computed tomography (SPECT) and DW MRI followed by acute LIF using tissue plasminogen activator. Recanalisation was observed in all patients, and eight improved clinically. The area of high signal intensity on pretreatment DW MRI was smaller than the low-uptake area on SPECT in all patients, and went on to infarction, as detected by MRI or CT 3 days after onset in all patients. It appears to correlate, at least clinically, with irreversible brain damage. Therefore, acute LIF should not be performed in patients with areas of high signal intensity in the cortex responsible for the symptoms. SPECT remains important, because areas normal on DW MRI with low uptake on SPECT often contribute to functional prognosis.
A 67-year-old woman had frequent subacute ileus, hearing difficulty, muscle atrophy and stroke-like episodes. Computed tomography revealed multiple low-density areas, which did not correlate with the vascular supply, in the cerebral cortex. She had metabolic disturbance comprising lactic acidosis and elevated pyruvate level. Her skeletal muscle biopsy specimen showed ragged-red fibers, and mitochondrial DNA analysis revealed a point mutation at position 3243, findings consistent with MELAS. Examination of her small intestine revealed a necrotic zone and numerous abnormal large mitochondria in the smooth muscle cells, vascular media and endothelium, and intestinal ganglion cells. The cerebral cortex showed multiple microcystic necrotic foci in cerebral cortex. Cactus-like pathology resembling the changes associated with Menkes' kinky hair disease and torpedoes were observed in the cerebellar Purkinje cells. The intestinal dysmotility due to MELAS and cerebellar changes were presumed to be associated with a disturbance of copper metabolism.
Oculocutaneous albinism (OCA) is an autosomal recessive disorder in which the biosynthesis of melanin is reduced or absent in skin, hair and eyes. Tyrosinase-related OCA (OCA1) is caused by mutations in the tyrosinase gene. Tyrosinase-negative OCA (OCA1A) is the most severe phenotype in which tyrosinase catalytic activity is completely lost, resulting in no mature melanin pigment. Yellow OCA (OCA1B) varies from very little pigment associated with whitish-blond hair to nearly normal pigment with dark-blond hair and skin. We determined the tyrosinase activity in melanocytes by the electron microscopic dihydroxyphenylalanine (EM-DOPA) reaction test using skin samples and analyzed tyrosinase gene mutations in nine Japanese patients with OCA. In 18 alleles of nine patients, the OCA1A-associated mutations, P310insC, R77Q and R278X, were found in seven, three and one alleles, respectively. Five patients who had these mutations in both alleles showed white hair, blue eyes and white skin and demonstrated no tyrosinase activity by the EM-DOPA reaction test. Three patients who had no tyrosinase gene mutation showed tyrosinase activity and heterogeneous clinical features. One patient in whom only an R77Q OCA1A mutation was found in one allele demonstrated a reduced tyrosinase activity, indicating OCA1B. This patient had white hair at birth, but it had turned blond by the age of 1 year. These results indicate that the EM-DOPA reaction test provides clear information on the status of tyrosinase activity which is essential for the identification of the disease subtype which in turn is important for the prognosis of patients with OCA.
Dystrophic epidermolysis bullosa (DEB), caused by mutations in the gene encoding type VII collagen (COL7A1), is known to show heterogeneous clinical phenotypes. Certain correlations between the nature or position of COL7A1 mutations and the resultant DEB phenotypes have been suggested, although such relationships may be more complex than initially thought. The purpose of the present study was to clarify the molecular basis of two different subtypes of dominant DEB (DDEB), EB pruriginosa and classical type. Interestingly, we found that both cases were caused by a missense glycine substitution mutation by different amino acids in the same codon of COL7A1 (G2028R and G2028A). These results further support the notion that different glycine substitution mutations in the same codon can lead to heterogeneous clinical phenotypes of DDEB, EB pruriginosa and classical type.