Vascular endothelial growth factor in diabetic retinopathy.
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Aqueous Humor↗
Biomedical subjects
S Katoh
Publications and source records attributed to S Katoh.
Functional roles of protein domains on rice alpha-amylase activity.
Characteristics of two rice alpha-amylases Amy1A and Amy3D, and those of two chimeric enzymes Amy1A/3D and Amy3D/1A, engineered from the two isozymes, were compared in the light of the functional roles of protein domains in alpha-amylase. The enzymes that have an Amy1A-type N-terminal domain, Amy1A and Amy1A/3D, showed high activity against soluble starch, while the enzymes that have an Amy3D-type barrel structure, Amy3D and Amy1A/3D, showed high activity in oligosaccharide hydrolysis. Rigidity of protein folding also significantly affected the enzyme activity in both soluble starch and oligosaccharide hydrolysis. Thus, the present work suggests that the structure of the N-terminal domain is important for stability and soluble starch hydrolysis, while the barrel structure that forms the active site significantly affects enzyme activities in oligosaccharide degradation. We have already characterized two rice alpha-amylase isozymes, Amy1A and Amy3D, and a chimeric enzyme engineered from these two isozymes, Amy1A/3D (Terashima et al. 1995, 1996a,b). In spite of the high homology (70%) of their amino acid sequences, Amy1A and Amy3D showed distinct differences in their enzymatic characteristics. The chimeric enzyme Amy1A/3D, which consists of an Amy1A-type N-terminal domain and an Amy3D-type barrel structure, inherited enzymatic characteristics from the both isozymes. In this work, one other chimeric enzyme, Amy3D/1A, which is the counterpart of Amy1A/3D, has been characterized. The characteristics of these four enzymes are discussed in the light of the functional roles of protein domains.
Amylases↗
Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts.
A water-soluble Chl a/b-protein (CP673) was isolated and purified from Brussels sprouts (Brassica oleracea L. var. gemmifera DC). The protein had a molecular mass of 78 kDa and an isoelectric point of 4.7, consisted of three or four subunits of 22 kDa and was extremely heat-stable. Although CP673 contained about one Chl a per protein, the blue and red absorption bands of Chl a that consisted of three or four Chl a forms with different absorption maxima suggested that there are several different modes or sites of binding for Chl a. Chl a/b ratio of larger than 10 also indicated that Chl b is present only in a small fraction of CP673. The heterogeneity of CP673 in terms of composition and binding of Chl suggests that Chl is not an intrinsic component of the Chl-protein. Homology search showed that the N-terminal amino acid sequence of CP673 is highly homologous with that of a 22 kDa protein that accumulates in water-stressed leaves of two Brassicaceae plants, rapeseed and radish, but not with those of the light-harvesting Chl a/b-proteins of photosynthesis. A possible function of the water-soluble Chl-protein was discussed.
Amino Acid Sequence↗
[Angle of defect on 123I-MIBG myocardial SPECT].
The quantitative assessment of infero-posterior defect on 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was studied in 150 patients with non-ischemic heart diseases at rest. The bull's eye map, obtained from the SPECT images at 4 hours after MIBG injection, was evaluated by generating the blacked out map which exhibits regions with reduced % uptake under mean-2 SD of 13 normal controls. The blacked out regions involved infero-posterior segments and were closely resembled to the sector form. The central angle of this sector, which was named as angle of defect (AOD), significantly correlated with both the heart-to-mediastinum activity ratio (H/M) and the myocardial clearance of MIBG. Because H/M and clearance are widely used as quantitative indices in MIBG myocardial scintigraphy, these results indicate that AOD can also be used as a quantitative index of abnormal cardiac sympathetic nervous function, which is likely to appear in infero-posterior regions in non-ischemic cardiac diseases.
3-Iodobenzylguanidine↗
Nerve growth factor rescues PC12 cells from apoptosis by increasing amount of bcl-2.
Nerve growth factor (NGF) suppressed the decrease in number of viable PC12 cells after serum withdrawal from culture medium. Accordingly, the amount of bcl-2, a suppressive effector of apoptosis, increased in these cells. Bcl-2 antisense oligonucleotide suppressed not only the NGF-induced increase in bcl-2 but also NGF-induced neuronal differentiation. Results of fluorescent DNA staining indicated that NGF inhibited the chromatin condensation of PC12 cells resulting from serum withdrawal and further that the bcl-2 antisense oligonucleotide canceled this effect of NGF. The present results suggest that NGF rescues PC12 cells from apoptosis induced by serum withdrawal via up-regulation of bcl-2.
Animals↗
Secondary structure and thermostability of the photosystem II manganese-stabilizing protein of the thermophilic cyanobacterium Synechococcus elongatus.
The secondary structure of the manganese-stabilizing protein of the thermophilic cyanobacterium Synechococcus elongatus in solution was investigated by Fourier-transform infrared (FT-IR) and circular dichroism (CD) spectroscopies. Both methods showed a high proportion of disordered structure (40-43%) and a relatively small amount of beta-sheet (23-24%) and alpha-helix (17-19%). The conformation of the protein remained essentially unchanged at temperatures up to 70 degrees C. Unfolding of the protein occurred at higher temperatures and FT-IR spectroscopy revealed that beta-sheet was more strongly unfolded than alpha-helix at 76 degrees C. The protein largely lost the ordered secondary structures at 90 degrees C, but, when cooled down to 30 degrees C, regained its original conformation. Thus, the cyanobacterial protein is very thermostable and its denaturation at an extremely high temperature is reversible.
Bacterial Proteins↗
Neurologic outcome in conservatively treated patients with incomplete closed traumatic cervical spinal cord injuries.
STUDY DESIGN: The neurologic outcomes in patients with conservatively managed incomplete closed traumatic cervical spinal cord injuries was evaluated using the motor scoring system and the Frankel classification. OBJECTIVES: To show that the motor scoring of recovery system combined with functional Frankel grading will make the documentation of final neurologic outcome more accurate for future comparisons of various methods of treatment. SUMMARY OF BACKGROUND DATA: The influence of surgical and pharmacologic methods of treatment on recovery remains debatable. METHODS: Sixty-three consecutive patients with incomplete cervical injuries who were admitted to the hospital within 2 days after injury were included. All patients were treated conservatively with 6 weeks of bedrest and 6 weeks of mobilization with neck support. RESULTS: Five patients had neurologic deterioration, and all but one patient recovered without surgery. The evaluation of 44 patients who were observed for more than 12 months showed that the preservation of sharp sensation below the level of injury was an indicator of a good prognosis in patients whose injuries were classified as Frankel B, and the degree of recovery of these patients according to the motor score system was comparable with that of patients who were classified as Frankel C. All patients classified as Frankel C who did not deteriorate recovered in Frankel grade. All but one of the patients in the Frankel D group recovered full motor power. The degrees of motor deficit and recovery did not correlate with the mechanism or the degree of the injury of the spinal axis. CONCLUSION: Conservative treatment remains a good option for patients with incomplete cervical cord injuries. It is hoped the current study will be a good basis for comparison of the neurologic outcomes of different treatment modalities.
Adolescent↗
Modification of alpha-amylase functions by protein engineering.
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Isoenzymes↗
Induction and its spread of apoptosis in rat spinal cord after mechanical trauma.
This study was undertaken to examine the spinal cord of rats after trauma for the induction of apoptosis. DNA ladder formation was demonstrated by gel electrophoresis of the DNA obtained from the spinal cord at the site of injury after trauma from 12 h to 8 days and was most significant on Days 3 and 4. As for the longitudinal spread of the injury in the spinal cord, the ladder formation was observed in the two segments adjacent to the site of trauma 3 days after trauma. Histological examination using in situ end labeling also demonstrated the appearance of apoptosis. These results provide the evidence for the induction of apoptosis in the spinal cord after trauma in rats.
Animals↗
Growth of the cervical spine with special reference to its lordosis and mobility.
STUDY DESIGN: The cervical spine of the healthy Japanese children aged between 1 year and 18 years was radiographically examined. OBJECTIVES: To examine the correlation between growth of the cervical vertebral body and the facet joint and the development of the cervical lordosis and intervertebral motion. SUMMARY OF BACKGROUND DATA: Although the growth of body height and facet angle have been well documented, their correlation with curvature or mobility has not been elucidated. METHODS: We evaluated plain lateral radiographs of 180 boys and 180 girls regarding diameters and central heights of the cervical vertebra, the anterior and posterior vertebral height ratio, body height index, the facet joint angles, and tilting and sliding motions. Cervical length as the summation of the central height from C3 to C7 and the cervical lordosis angle (C3-C7 angle) were also measured. RESULTS: The mean C3-C7 angle and body height index gradually decreased until 9 years of age and then increased. The C3-C7 angle showed a significant correlation with cervical length, body height index, and facet joint angles before 9 years of age, and with cervical length and body height index after 9 years of age but not with facet joint angles. Facet joint angle decreased until 10 years of age and remained almost unchanged thereafter. Total sliding showed a significant age-related decrease and showed a significant correlation with facet joint angle. CONCLUSION: Although the lordosis angle showed a significant correlation with the other values, cervical length, body height index, and facet joint angle, the determinants of the lordosis could not be elucidate in the present study. As for the mobility of the cervical spine, changes of tilting motion were small, whereas changes of sliding motion were restricted by the change of orientation of the facet joints.
Adolescent↗
Synthesis and selective coronary vasodilatory activity of 3,4-dihydro-2,2-bis(methoxymethyl)-2H-1-benzopyran-3-ol derivatives: novel potassium channel openers.
A variety of compounds having a benzopyran such as levcromakalim generally exhibit potent antihypertensive activity. During extensive investigations aimed toward identifying K+ channel openers having selective coronary vasodilation without potent hypotensive and tachycardiac effects, we synthesized a series of 3,4-dihydro-2H-1-benzopyran-3-ol derivatives modified at positions 2, 4, and 6 in the benzopyran ring. Initially, compounds having two methoxymethyl groups at position 2 were found to show a selective effect on coronary blood flow (CoBF) relative to mean arterial pressure (MAP) in anesthetized dogs. To find more potent vasodilators, various benzopyran derivatives modified at position 4 were synthesized and structure-activity relationships were examined by evaluation of the extent and duration of the increase in CoBF in anesthetized dogs. As a result, compounds having a (1,6-dihydro-6-oxopyridazin-3-yl)amino group at position 4, in addition to the two methoxymethyl groups at position 2, were found to be more potent and to have an improved duration of action. Among these compounds, JTV-506, (-)-(3S,4R)-6-cyano-3,4-dihydro-4-[(1,6-dihydro-1-methyl-6-oxopyridaz in-3-yl)amino]-2,2-bis(methoxymethyl)-2H-1-benzopyran-3-ol, exhibited good selectivity for its effect. Administration of this compound (0.03 mg/kg, p.o.) elicited an increase of CoBF without a change of systemic blood pressure and heart rate (HR) in conscious dogs. Further evaluation was performed with respect to (i) the selectivity of its action on the coronary artery versus the aorta and (ii) its effects on MAP, HR, and electrocardiographic ST elevation. As a result, JTV-506 was selected as a potent and selective coronary vasodilator with various pharmacological features favoring clinical development.
Animals↗
Structure of the human cytomegalovirus protease catalytic domain reveals a novel serine protease fold and catalytic triad.
Proteolytic processing of capsid assembly protein precursors by herpesvirus proteases is essential for virion maturation. A 2.5 A crystal structure of the human cytomegalovirus protease catalytic domain has been determined by X-ray diffraction. The structure defines a new class of serine protease with respect to global-fold topology and has a catalytic triad consisting of Ser-132, His-63, and His-157 in contrast with the Ser-His-Asp triads found in other serine proteases. However, catalytic machinery for activating the serine nucleophile and stabilizing a tetrahedral transition state is oriented similarly to that for members of the trypsin-like and subtilisin-like serine protease families. Formation of the active dimer is mediated primarily by burying a helix of one protomer into a deep cleft in the protein surface of the other.
Amino Acid Sequence↗
Role of cytokines in leukemic type growth of myelodysplastic CD34+ cells.
The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.
Acute Disease↗
Use of peptide immunization for porcine insulin of a very high homology with a host protein.
An anti-peptide antibody was obtained against a peptide corresponding to the 12 amino acids of the C-terminal region of porcine insulin B chain. The adsorption characteristics of this antibody were compared with those of anti-porcine insulin and anti-sheep insulin antibodies. Immunization of rabbits using the peptide corresponding to the C-terminal region of porcine insulin B chain produced an anti-peptide antibody which reacted with native porcine insulin with a much higher association constant than that of an anti-porcine insulin antibody. In addition, this immunization technique did not cause any observable physiologically harmful effects, such as hypoglycemia, in the immunized rabbits. Thus, peptide immunization may be a useful strategy when target proteins have biological activity and/or toxicity, and also have a very high degree of homology with the corresponding proteins of the immunized animal, which may inhibit the production of antibodies with a high association constant.
Adsorption↗
Morphologic analysis of the facet joint in the immature lumbosacral spine with special reference to spondylolysis.
STUDY DESIGN: Morphological analysis was performed of the facet joint of the normal and spondylolytic lumbosacral spine in children and adolescents. OBJECTIVES: This study was performed to estimate the influence of spondylolysis on growth of the neural arch of the lumbosacral spine. SUMMARY OF BACKGROUND DATA: The development of the facet joint and its relation to spondylolysis have not been documented in the literature. METHODS: The dimension and orientation of the facet joint at L5/S were measured on radiographs and computed tomography scans from 144 boys without pars defects and 104 boys with pars defects. The latter group was further investigated according to the stage of pars defects. Patients in both groups were between 9 and 18 years of age. RESULTS: Growth of the facet joint in the sagittal and transverse directions and the increase of the transverse angle were remarkable up to approximately 13 years of age. Concavity of the facet joints also progressed in children of the same age. The growth of the facet joint in patients with spondylolysis was significantly retarded as the pars defects advanced from the progressive to the terminal stage. The joint surface was more coronal in orientation and flatter in shape compared with controls. CONCLUSIONS: The present results suggest that pars defects occurring in children disturb or retard the growth of the facet joint and that the morphological characteristics of the joint surfaces in patients with spondylolysis are the consequence of these defects.
Adolescent↗
Inhibition of protein serine/threonine phosphatases by fumonisin B1, a mycotoxin.
Fumonisin B1 (FB1), a mycotoxin produced by the fungus Fusarium moniliforme, which is a common contaminant of corn, is suspected to be a cause of human esophageal cancer. FB1 is hepatotoxic and hepatocarcinogenic in rats, and although the mechanisms involved have not been clarified, the latter is associated with a weak initiating activity. The effects of FB1 on the activity of protein serine/threonine phosphatases (PPs) (PP1, PP2A, PP2B, PP2C and PP5/T/K/H) were investigated in the present study. Inhibition of dephosphorylation was noted for all five PPs with IC50 values of 80 microM-3000 microM. Among the five PPs examined, PP5 was most sensitive with an IC50 of 80 microM. This concentration is comparable to that estimated to be reached in the rat body by feeding FB1 to obtain hepatic tumors. Inhibition of PP5 could thus play important roles in the toxicity and carcinogenic action of FB1.
Animals↗
Validation of the American Spinal Injury Association (ASIA) motor score and the National Acute Spinal Cord Injury Study (NASCIS) motor score.
STUDY DESIGN: In this study the motor scores of 62 consecutive acute spinal cord-injured patients were retrospectively reviewed. OBJECTIVE: The reliability of the American Spinal Injury Association and National Acute Spinal Cord Injury Study motor scores, compared with the conventional motor scores, was retrospectively assessed. SUMMARY OF BACKGROUND DATA: The reliability of the American Spinal Injury Association and National Acute Spinal Cord Injury Study scores has not as yet been confirmed. METHODS: Sixty-two consecutive adult patients admitted within 7 days of acute spinal cord injury between April, 1983, and September, 1992, were evaluated. The motor deficit percentage and the motor recovery percentage of each of the American Spinal Injury Association and the National Acute Spinal Cord Injury Study motor scores were compared with those of the conventional motor score. From the initial and final motor score, the motor deficit percentage and motor recovery percentage were calculated. There were 38 patients with cervical and thoracic lesions, 12 patients with dorso-lumbar lesions, and 12 patients with lower lumbar lesions. The average follow-up period was 41 months. RESULTS: Both the American Spinal Injury Association motor score and the National Acute Spinal Cord Injury Study motor score were representative of the conventional motor score for the evaluation of the motor deficit percentage and the motor recovery percentage in all levels (P < 0.0001). The differences in all correlation coefficients between the American Spinal Injury Association motor score and the National Acute Spinal Cord Injury Study motor score were not statistically significant in all levels and in every group. CONCLUSIONS: The American Spinal Injury Association and National Acute Spinal Cord Injury Study motor scores can both be used for the neurological quantification of motor deficit and motor recovery.
Adolescent↗
Hepatocyte growth factor induces transglutaminase activity that negatively regulates the growth signal in primary cultured hepatocytes.
Transglutaminase (TGase) activity increased 2.5-fold at 6 h after treatment of rat hepatocytes with 117 nM hepatocyte growth factor (HGF). In the same manner, putrescine incorporation into proteins of cells occurred in HGF-treated cells but did not in those pretreated with monodansylcadaverine (MDC), a TGase inhibitor, even in the presence of HGF. These results suggest that HGF-induced TGase was active and catalyzed some cross-linkage reaction. Cycloheximide completely blocked the increase in TGase activity induced by HGF, suggesting that HGF stimulated de novo synthesis of TGase within 6 h. Both [35S]methionine incorporation and Northern blotting analyses supported this possibility. Pretreatment of cells with MDC additionally increased HGF-induced DNA synthesis and the ratio of cells in S-phase. Similarly, TGase antisense oligonucleotide inhibited de novo synthesis of TGase, resulting in increase in the ratio of S-phase cells in the presence of HGF. Analyses of cross-linking of HGF to the receptor indicated that the antisense oligonucleotide inhibited the downregulation of HGF receptor subsequent to HGF-addition. These results provide the first evidence for inducibility of de novo synthesis of TGase by HGF and suggest that TGase negatively regulates the growth signal of HGF through the downregulation of receptor.
Animals↗