[Present status of emergency laboratory tests: importance and problems from the viewpoint of a prefectural governmental hospital].
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Clinical Laboratory Techniques↗
Biomedical subjects
K Taira
Publications and source records attributed to K Taira.
Urinary cross-linked fibrin degradation products in glomerular disease with crescents.
The concentration of cross-linked fibrin degradation products (XLFDP) in urine were determined by enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA) in patients with several types of glomerulonephritis with crescents (CrGN). In patients with "active" cellular crescents, increased levels of XLFDP correlated with the percentage of glomeruli containing crescents. Dysmorphic erythrocytes, suggestive of glomerular bleeding, were observed in all of the patients with CrGN, and the urinary red cell counts (URCC) also correlated with percentage of glomeruli containing crescents. The absence of correlation between urinary XLFDP and URCC or urinary protein suggested that lysis of fibrin within crescents may contribute to the urinary excretion of XLFDP in CrGN. The measurement of urinary XLFDP in CrGN is likely to be of value in assessing the activity of glomerular lesions but not renal function.
Adolescent↗
Probing the functional role of phenylalanine-31 of Escherichia coli dihydrofolate reductase by site-directed mutagenesis.
The role of Phe-31 of Escherichia coli dihydrofolate reductase in binding and catalysis was probed by amino acid substitution. Phe-31, a strictly conserved residue located in a hydrophobic pocket and interacting with the pteroyl moiety of dihydrofolate (H2F), was replaced by Tyr and Val. The kinetic behavior of the mutant enzymes in general is similar to that of the wild type. The rate-limiting step for both mutant enzymes is the release of tetrahydrofolate (H4F) from the E X NADPH X H4F ternary complex as determined for the wild type. The 2-fold increase in V for the two mutant enzymes arises from faster dissociation of H4F from the enzyme-product complex. The quantitative effect of these mutations is to decrease the rate of hydride transfer, although not to the extent that this step becomes partially rate limiting, but to accelerate the dissociation rates of tetrahydrofolate from product complexes so that the opposing effects are nearly compensating.
Amino Acids↗
Effect of single amino acid replacements on the folding and stability of dihydrofolate reductase from Escherichia coli.
The role of the secondary structure in the folding mechanism of dihydrofolate reductase from Escherichia coli was probed by studying the effects of amino acid replacements in two alpha helices and two strands of the central beta sheet on the folding and stability. The effects on stability could be qualitatively understood in terms of the X-ray structure for the wild-type protein by invoking electrostatic, hydrophobic, or hydrogen-bonding interactions. Kinetic studies focused on the two slow reactions that are thought to reflect the unfolding/refolding of two stable native conformers to/from their respective folding intermediates [Touchette, N. A., Perry, K. M., & Matthews, C. R. (1986) Biochemistry 25, 5445-5452]. Replacements at three different positions in helix alpha B selectively alter the relaxation time for unfolding while a single replacement in helix alpha C selectively alters the relaxation time for refolding. This behavior is characteristic of mutations that change the stability of the protein but do not affect the rate-limiting step. In striking contrast, replacements in strands beta F and beta G can affect both unfolding and refolding relaxation times. This behavior shows that these mutations alter the rate-limiting step in these native-to-intermediate folding reactions. It is proposed that the intermediates have an incorrectly formed beta sheet whose maturation to the structure found in the native conformation is one of the slow steps in folding.
Amino Acids↗
The representation of the oral structures in the first somatosensory cortex of the cat.
Applying light mechanical stimulations to the oral structures, multi-unit recordings (MUR) were performed, and receptive fields of neurons were defined in the somatosensory cortex S I of the cat. Oral representation was confirmed in the circumscribed area of the anterior coronal gyrus rostral to the facial area in the following order: the contralateral lips, the contralateral periodontal tissues such as the gingivae and periodontal membranes, the middle and ipsilateral part of the periodontal tissues, and the palate and tongue in a caudorostral direction. The representation of the lip and perioral tissues of the lower jaw was found on the medial side of the coronal gyrus, while the upper one was found on the lateral side. The same oral representation was confirmed by single-unit recording (SUR) analysis in the anterior coronal gyrus. The representation area of the contralateral, middle and ipsilateral site of the non-hairy lips and periodontal tissues was found in cytoarchitectural field, areas 3b and 2; somatic koniocortex.
Animals↗
Characteristics of periodontal mechanosensitive neurons in the first somatosensory cortex of the cat.
Response properties of periodontal mechanosensitive (PM) units which were activated by the mechanical stimulation of canine teeth were studied in the oral area of somatosensory cortex S I (anterior coronal gyrus) of the cat. Spike discharges of PM units were recorded as post-stimulus time histograms (PSTHs). Most PM units showed more or less spontaneous activity and phasic response properties to the trapezoid waveform stimulation. When the rate of stimulus application was increased, the initial peak value of the PSTH increased and its crest time decreased. Direction-selective PM units which changed their response discharge rates according to the direction of the stimuli applied to the canine teeth were found in this cortical area. Posterior-directed mechanical stimulation was more effective for eliciting the spike discharges of PM units than anterior-directed stimulation. Applying the test and conditioning stimuli to the contralateral or ipsilateral canine teeth, interactions of afferent inputs received by the mechanoreceptors of the periodontal tissues of different teeth were studied. Test responses of PM units were inhibited for 20-50 ms after the onset of the conditioning stimuli.
Adaptation, Physiological↗
Activity of blood coagulation factor XIII as a prognostic indicator in patients with Henoch-Schönlein purpura. Efficacy of factor XIII substitution.
UNLABELLED: Determination of coagulation Factor XIII (F XIII)-related parameters in 21 patients with Henoch-Schönlein purpura documented a significant decrease of F XIII activity as well as of the F XIII-related antigenic determinants. Subgroup analysis with regard to the clinical symptoms showed an even further decrease of these parameters in patients with gastrointestinal complications. Stimulated by these findings a substitution therapy with a F XIII concentrate was initiated in those patients whose F XIII activity in plasma remained low and who developed severe abdominal pain accompanied by persisting gastrointestinal bleeding. This therapeutic approach not only corrected the laboratory data, but more important led to a cessation of pain and bleeding. A rapid decrease of F XIII levels after transfusion below 40 U/ml was indicative of relapse of abdominal symptoms, while increasing values were associated with the recovery of the patients. IN CONCLUSION: F XIII activity determinations appear to have a predictive value in patients with Henoch-Schönlein purpura, and the administration of F XIII concentrates may contribute to the improvement of gastrointestinal complications.
Child↗
[Comparative clinical trial of HBK and amikacin (AMK) in the treatment of respiratory infections].
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Adult↗
Immunoelectron microscopic study of glomerular lesions using a postembedding method with a protein A-gold complex.
Renal biopsy tissue from 33 children with various glomerular diseases has been investigated by electron microscopy using a postembedding immunostaining technique with a protein A-gold complex in order to establish more precise correlations between immunopathologic and morphologic findings in glomeruli. This technique could detect immunoglobulins (IgG, IgA, and IgM), complement factor (C3c), and fibrinogen-related antigen. The immunoreactivity of these antigens was essentially confined to the mesangial, paramesangial, subendothelial, and subepithelial 'electron-dense deposits' in the glomeruli. Except for IgM and C3c in the case of glomerular sclerosis, the distribution of the mentioned factors was even in the electron-dense deposits, as could be shown by 'double-immunolabeling'. From the above-mentioned findings one can conclude that several of the localized factors are associated with the formation of electron-dense deposits, the ultrastructural hallmarks of glomerular disease.
Antigens↗
A case report of growth attenuation during methionyl human growth hormone treatment.
A 10-year-old child with idiopathic growth hormone deficiency was treated with recombinant methionyl human growth hormone (m-hGH, Somatonorm) at a dose of 14 IU/week. Height increased from 122.3 to 126.5 cm during the first 9 months of treatment (5.6 cm/y), but only from 126.5 to 126.6 cm during the next 3 month of treatment (0.4 cm/y). Anti-hGH antibody was detected at 2 months of treatment, reached its maximum at the end of 9 months with a titer of 10(6) and a binding capacity of 2.0 mg/L. After switching from m-hGH to pituitary extracted hGH (p-hGH) treatment, his height increased again from 126.6 to 132.2 cm during the next 12 months of p-hGH treatment (5.6 cm/y). The cause of growth attenuation during m-hGH treatment was concluded to be the high titer of anti-hGH antibody. This is the first case in Japan and one of only three cases in which growth attenuation occurred during m-hGH treatment.
Antibodies↗
A freeze-fracture study of the plasma membrane of the Ito cell in the normal rat liver.
The plasma membrane of the Ito cell in the normal rat liver was studied by freeze-fracture electron microscopy. Ito cells appeared to adhere to endothelial cells or to be embedded in the microvilli of hepatocytes. Ramified processes with a few microvilli of the cell extended along the endothelial cells. Caveolae were constantly seen on the plasma membrane, but their numbers varied among cells. Two different patterns of intramembranous particles were found on the plasma membrane of the Ito cells: most cells showed an even distribution of the particles, but the others, aggregates of them. Particle-free domains were seen on the plasma membrane in some Ito cells. Piles of concave or convex sheets were sometimes seen in the freeze-fractured lipid droplets.
Animals↗
[Experimental models for studying the avoidance response in mice and the anti-amnesic effect of prolyl endopeptidase inhibitors].
Prolyl endopeptidase (PPCE) plays an important role in the degradation of biologically active peptides such as vasopressin which facilitates the process of learning and memory. Here, the effect of synthetic PPCE inhibitors (Z-Pro-, Suc-Pro-, Suc-Pyr-, Suc-Sar- and Z-prolinal) on the acquisition and retention of avoidance response was studied. Using mice of the ddY strain, tests were performed both in repeated trials of an active avoidance task and in a newly contrived one-trial passive-active avoidance task. The applicability of both tests for the evaluation of the anti-amnesic effect of the drugs was confirmed by the effect of scopolamine and arginine vasopressin (AVP). The most potent inhibitor, Z-Pro-prolinal, facilitated the acquisition of active avoidance response and retarded the extinction of the response. Other inhibitors also facilitated the retention of the acquired response. In the one-trial passive-active avoidance test, the facilitating effect of the PPCE inhibitors on the acquisition was parallel to their activity as a PPCE inhibitor. Scopolamine-induced amnesia was also improved by the inhibitors. These results suggest that the anti-amnesic effect of PPCE inhibitors is partially attributed to their inhibitory effect on the breakdown of AVP in the brain.
Amino Acids↗
Specificities of extracellular and ribosomal serine proteinases from Bacillus natto, a food microorganism.
The specificities of extracellular and ribosomal serine proteinase from Bacillus natto, a food microorganism, were investigated. Both proteins have highly restricted and characteristic specificities. With the extracellular serine proteinase, initial cleavage site was observed at Leu15-Tyr16, secondary site at Ser9-His10 and additional cleavage sites at Gln4-His5 and His5-Leu6 in the oxidized insulin B-chain. Hydrolysis of proangiotensin with the extracellular serine proteinase was observed primarily at Phe8-His9 and secondary at Tyr4-Ile5. The extracellular serine proteinase has a Km of 0.08 mM and kcat of 3 S-1 for angiotensin hydrolysis. With the ribosomal proteinase, initial cleavage site of the oxidized insulin B-chain was observed at Leu15-Tyr16 and additional cleavage site at Phe24-Phe25. Hydrolysis of proangiotensin was observed at Tyr4-Ile5 bond with the ribosomal proteinase.
Angiotensinogen↗
Importance of a hydrophobic residue in binding and catalysis by dihydrofolate reductase.
A conserved residue at the dihydrofolate binding site of dihydrofolate reductase (EC 1.5.1.3), leucine-54, was replaced with glycine to ascertain the role of this hydrophobic amino acid. The effect of the mutation is both to increase the dissociation rate of dihydrofolate and decrease the rate of hydride transfer thus changing the rate-limiting step in catalysis from product loss (leucine-54) to hydride transfer (glycine-54). The total stabilization by leucine-54 of the transition state for hydride transfer is ca. 10(4)-fold (delta delta G approximately 5.4 kcal/mol) at subsaturating dihydrofolate levels relative to free enzyme despite its location some 10 A from the site of chemical reaction.
Binding Sites↗
Effect of increased systemic venous pressure on thoracic duct and peripheral lymph flow in dogs.
In congestive heart failure, lymph flow from the cannulated thoracic duct is greatly increased. However, there has been scant data on lymph flow in the intact lymphatic system with systemic circulatory congestion. In the present study, thoracic duct and peripheral lymph flow were qualitatively determined using heated cross-thermocouples in seven mongrel dogs. Central venous pressure was raised artificially by infusing large volumes of crystalloid solution equivalent to a maximum of 30% of body weight. Although both thoracic duct and peripheral lymph flow increased with an intact (closed) lymphatic system, the increase was notably less than with a transected (opened) cervical thoracic duct. With systemic circulatory congestion, cannulated thoracic duct lymph flow circumvents a major lymph impediment to lymph flow (i.e. high central venous pressure) and therefore considerably overestimates in vivo central lymph flow in this condition.
Animals↗
Stereoelectronic control in peptide bond formation. Ab initio calculations and speculations on the mechanism of action of serine proteases.
Ab initio molecular orbital calculations have been performed on the reaction profile for the addition/elimination reaction between ammonia and formic acid, proceeding via a tetrahedral intermediate: NH3 + HCO2H----H2NCH(OH)2----NH2CHO + H2O. Calculated transition state energies for the first addition step of the reaction revealed that a lone pair on the oxygen of the OH group, which is antiperiplanar to the attacking nitrogen, stabilized the transition state by 3.9 kcal/mol, thus supporting the hypothesis of stereoelectronic control for this reaction. In addition, a secondary, counterbalancing stereoelectronic effect stabilizes the second step, water elimination, transition state by 3.1 kcal/mol if the lone pair on the leaving water oxygen is not antiperiplanar to the C-N bond. The best conformation for the transition states was thus one with a lone pair antiperiplanar to the adjacent scissile bond and also one without a lone-pair orbital on the scissile bond oxygen or nitrogen antiperiplanar to the adjacent polar bond. The significance of these stereoelectronic effects for the mechanism of action of serine proteases is discussed.
Calorimetry↗
A freeze-fracture study on the basolateral plasma membrane of the gastric parietal cells in fasting and refed rats.
The basolateral plasma membrane of the gastric parietal cells in rats after food-deprivation and food-restitution was studied by thin-section and freeze-fracture electron microscopy. A decrease in the number of tubulovesicles and dilatation of the canalicular lumen were generally observed in the parietal cells of the refed rats. Basal folds, demonstrated both in fasting and food-resupplied rat groups parietal cells by thin-section electron microscopy, appears as branched furrows on the P face and branched wrinkles on the E face plasma membrane by the freeze-fracture replica method. Parietal cells providing numerous basal folds appeared to be more numerous in refed rat gastric gland. The basal folds may represent, at least to some extent, a reservoir of a surplus plasma membrane and play an important role in secreting substances into and also absorbing substances from the blood capillary via the underlying connective tissue.
Animals↗
Localization of intrarenal cross-linked fibrin in children with various renal diseases.
The localization of intrarenal cross-linked fibrin was examined by the effect of monochloroacetic acid treatment on the kidney sections. In acute glomerulonephritis or in mild diffuse or focal proliferative type of nephritis, cross-linked fibrin was observed mainly within glomerular capillary walls. Extension of cross-linked fibrin deposit over the mesangium or sclerotic area was seen in moderate to severe proliferative type of nephritis or in membranoproliferative glomerulonephritis. In hemolytic uremic syndrome or disseminated intravascular coagulation syndrome, cross-linked fibrin was detected within glomeruli and vessels.
Acetates↗