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Biomedical subjects

T Kashiwagi

Publications and source records attributed to T Kashiwagi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Pleomorphic angioleiomyoma.

We describe two cases of pleomorphic angioleiomyoma. In one case, a 46-year-old man presented with a single nodule on his scrotum of 1 year's duration, and in another, a 38-year-old woman presented with a single nodule on her right knee of 1 year's duration. In both cases, histopathologic examination showed a well-circumscribed nodule composed of smooth muscle and numerous veins and capillaries. Contrary to the ordinary angioleiomyoma, marked nuclear pleomorphism was noted. Although mitoses were rare, immunohistochemistry revealed many tumor cells that were positive for proliferating cell nuclear antigen, Ki-67, and p53, indicating that the pleomorphic appearance does not simply represent a degenerative change of some tumor cells.

Adult↗
PubMed2000

Antibody-scanning and epitope-tagging methods; molecular mapping of proteins using antibodies.

Because synthetic short peptides bearing critical binding residues, can chemically mimic the folded antigenic determinants on proteins, short synthetic peptides can generate antibodies that react with cognate sequences in intact folded proteins. According to this mimotope theory, we produced site-specific antibodies by immunization with short peptides which overlapped each other and covered the entire protein, and used them for domain mapping of influenza virus RNA polymerase (antibody-scanning method). We also used a tagged-epitope and its monoclonal antibodies for topology mapping of clathrin light chains in clathrin triskelions by electron microscopy. Both methods using specific epitopes in combination with their antibodies enable us to determine the domains of interesting proteins systematically without the need to generate monoclonal antibodies or mutant proteins.

Amino Acid Sequence↗
PubMed2000

Light activation of phospholipase A2 in the photoreceptor of the crayfish (Procambarus clarkii).

Retinal lipids of crayfish, kept at 4 degrees C under continuous darkness for 3 weeks, consisted mainly of phosphatidylcholine (PC) and phosphatidylethanolamine (PE); sphingomyelin (SM), phosphatidylinositol (PI) and phosphatidylserine (PS) were minor contributors. PI, involved in the phototransduction cascade, never reached greater concentrations than 7% of the total. High concentrations of polyunsaturated fatty acids (PUFA) such as 20:4n-6, 20:5n-3 and 22:6n-3 (DHA, docosahexaenoic acid) were present in PC, PE and PS, but scarce in SM and PI. In retinae of crayfish kept at 4 degrees C in darkness for 3 weeks and then exposed to white light (6 h; ca. 4,500 lx), SM and PS remained seemingly unaffected. PC, however, significantly decreased within 10 min to 65% of the initial value and 50% at 180 min. To study the reduction of PC, lipids of retinae suspended in physiological solution with/without phospholipase C (PLC) and phospholipase A2 (PLA2) inhibitors such as DMDA (= DEDA), manoalide, ET-18-OCH3, and U-73122 were measured. Only free fatty acids (FFA) of retinae with inhibitors of PLA2 like DMDA and manoalide decreased. Retinae irradiated by white light for 3 h displayed a significant reduction of PC, compared with those that had remained in continuous darkness. However, the PC of retinae with PLA2-inhibitors was not decreased by light. Our results provide evidence that not only photoreceptor cell PLC, but also PLA2 is activated by light.

Animals↗
PubMed2000

Detection and measurement of urinary 2-hydroxyestradiol 17-sulfate, a potential placental antioxidant during pregnancy.

BACKGROUND: Preeclampsia is associated with a quantitative imbalance between lipid peroxide and an antioxidant coproduced in the placenta. To investigate our hypothesis that 2-hydroxyestradiol 17-sulfate (2-OH-ES) is the placental antioxidant during pregnancy, we developed an assay for 2-OH-ES in urine and studied samples from women with and without preeclampsia. METHODS: The detection and measurement of 2-OH-ES in the urine of pregnant women were performed by RIA using highly specific antiserum to 2-OH-ES. To confirm the reliability of the RIA method, the same samples were analyzed by HPLC using an electrochemical detector. RESULTS: Urinary 2-OH-ES values obtained by RIA showed a close relationship to those obtained by HPLC (y = 1.1x - 0.01; r = 0.96). The urinary 2-OH-ES concentrations during the first, second, and third trimesters were 2. 0 +/- 0.6 (mean +/- SE, n = 13), 5.3 +/- 1.3 (n = 21), and 15.3 +/- 2.0 microg/mg creatinine (n = 54), respectively, and <0.15 microg/mg creatinine (n = 10) at 2-24 h after delivery. The concentrations in preeclamptic women during the third trimester were significantly lower, 3.9 +/- 1.9 microg/mg creatinine (mean +/- SE, n = 12). CONCLUSIONS: RIA can be used to measure urinary 2-OH-ES during pregnancy. The increase in urinary 2-OH-ES during gestation, its decrease after delivery, and the lower values in preeclampsia are consistent with a role of 2-OH-ES as a placental antioxidant.

Adolescent↗
PubMed2000

Evaluation of portosystemic collaterals by SPECT imaging after endoscopic variceal sclerotherapy: usefulness for predicting recurrence.

UNLABELLED: Bleeding from esophageal varices is a major cause of morbidity and mortality in cirrhotic patients. Identification of patients at high risk for bleeding is particularly important. The aim of this study was to determine whether detection of portosystemic collaterals by SPECT could predict the outcome of endoscopic injection sclerotherapy of esophageal varices and be useful for selecting appropriate therapy. METHODS: Sixty-two patients with liver cirrhosis who were considered at high risk of bleeding were treated with endoscopic injection sclerotherapy. Endoscopy was performed every 3 mo after therapy or until bleeding occurred. Before and within 2 wk after therapy, tomographic images of intra-abdominal blood pool were constructed by SPECT. RESULTS: Before therapy, the following portosystemic collateral routes were observed: coronary veins in 53 (85.5%) of 62 patients, short gastric veins in 8 patients (12.9%), splenorenal shunts in 10 patients (16.1%), and paraumbilical veins in 6 patients (9.7%). Patients positive for imaging of coronary veins were divided into 3 groups on the basis of changes in images after therapy: complete responders (n = 17), whose coronary vein images disappeared completely; partial responders (n = 18), whose images became smaller; and nonresponders (n = 18), whose images did not change significantly before or after therapy. The rates of recurrence after endoscopic injection sclerotherapy until 6 mo in complete responders (4/17, 23.5%) and partial responders (7/18, 38.9%) were significantly less (P < 0.05) than that in nonresponders (11/13, 84.6%). The rate of recurrence of esophageal varices until 6 mo in nonresponders treated with additional submucosal injection sclerotherapy (1/5, 20.0%) was significantly less (P < 0.05) than that in nonresponders without additional submucosal injection sclerotherapy (11/13, 84.6%). CONCLUSION: Abdominal blood-pool SPECT, a noninvasive method, is useful for evaluating the therapeutic effectiveness of endoscopic sclerotherapy, for predicting the recurrence of varices, and for selecting appropriate management after sclerotherapy.

Collateral Circulation↗
PubMed1999

Serum 2-hydroxyestradiol 17-sulphate in pregnancy.

2-Hydroxyestradiol 17-sulphate (2-OH E2-17-S) is a catecholized form of sulphated estrogen. In vitro studies showed that its antioxidative effect is almost equal to that of free catecholestrogens, such as 2-OH E2 or 4-OH E2 and alpha-tocoferol, but the existance of 2-OH E2-17-S in human serum has not yet been made clear. 2-OH E2-17-S strongly antagonizes lipid peroxidation, and so it may play an important role in pregnancy, for example as an anti-oxidant in pregnancy-induced hypertension (PIH). The serum level of 2-OH E2-17-S was measured during mid to late pregnancy by a direct radioimmunoassay (RIA) without hydrolysis. The serum levels at 28-31 weeks, 32-35 weeks and 36-40 weeks of gestation were 4.68+/-0.93 (mean+/-SE), 8.38+/-1.21 and 18.31+/-3.41 nmol/l, respectively. The serum level in PIH cases at 36-40 weeks (4.64+/-1.29 nmol/l) was significantly lower than that in normal pregnancy. The 2-OH E2-17-S level in umbilical arteries was significantly higher than that in maternal peripheral vein. These results suggest that the feto-placental unit plays an important role in catecholizing E2-17-S to 2-OH E2-17-S, which may act as an antioxidant in pregnancy.

Estradiol↗
PubMed1998

Application of synchrotron radiation to ultrafast spectroscopy.

A novel application of synchrotron radiation to ultrafast optical spectroscopy is demonstrated. The application is based on the short coherence time of broadband synchrotron radiation and employs a conventional interferometer. From a detailed study of the coherence of synchrotron radiation, it is shown that the coherent interference between two synchrotron radiation beams, split from a single beam, can provide ultimate time resolution down to a few femtoseconds. Experimental results of ultrafast spectroscopy using broadband synchrotron radiation are presented; these include free-induction decay and photon echoes in the visible and ultraviolet regions.

Journal Article↗
PubMed1998

Crystallization and preliminary X-ray analysis of the periplasmic receptor (PotF) of the putrescine transport system in Escherichia coli.

The primary receptor (PotF) of the putrescine transport system in E. coli has been crystallized by the hanging-drop vapor-diffusion technique. The crystals belong to the space group P21212 with unit-cell dimensions a = 269.4, b = 82.33 and c = 93.74 A. The crystals diffract beyond 2.2 A with a rotating-anode X-ray source. A complete data set from the native crystals has been collected and processed at 2.3 A resolution. Two heavy-atom derivatives have been prepared from the same Pt compound at 293 and 277 K. The difference Patterson maps revealed completely different major heavy-atom sites between these two derivatives.

Biological Transport↗
PubMed1998

[Releasing phenomenon of learned movements].

Involuntary movements that resembled the shooting of a basketball and piano playing were observed after brain damage in a 13-year-old female and a 74-year-old female, respectively. The movements were characterized as involuntarily triggered movements that occurred in the presence and absence of exteroceptive stimuli, movements had been practiced repeatedly just before the occurrence of the brain damage, and that could be stopped on command. According to the MRI findings, the lesions extended into the pre-supplementary motor area (pre-SMA). The characteristics of the patients movements were different from previously reported involuntary movements such as compulsive manipulation of tools, utilization behavior, and imitation behavior. Hikosaka et al (1996) reported the role of the pre-SMA in learning new sequential procedures. We speculate that damage to the pre-SMA may be associated with the etiology of these movements.

Adolescent↗
PubMed1997

The novel acidophilic structure of the killer toxin from halotolerant yeast demonstrates remarkable folding similarity with a fungal killer toxin.

BACKGROUND: Several strains of yeasts and fungi produce proteinous substances, termed killer toxins, which kill sensitive strains. The SMK toxin, secreted by the halotolerant yeast Pichia farinosa KK1 strain, uniquely exhibits its maximum killer activity under conditions of acidic pH and high salt concentration. The toxin is composed of two distinct subunits, alpha and beta, which tightly interact with each other under acidic conditions. However, they are easily dissociated under neutral conditions and lose the killer activity. The three-dimensional structure of the SMK toxin will provide a better understanding of the mechanism of toxicity of this protein and the cause of its unique pH-dependent stability. RESULTS: Two crystal structures of the SMK toxin have been determined at 1.8 A resolution in different ionic strength conditions. The two subunits, alpha and beta, are jointly folded into an ellipsoidal, single domain structure belonging to the alpha/beta-sandwich family. The folding topology of the SMK toxin is essentially the same as that of the fungal killer toxin, KP4. This shared topology contains two left-handed split betaalphabeta motifs, which are rare in the other proteins. Many acidic residues are clustered at the bottom of the SMK toxin molecule. Some of the carboxyl sidechains interact with each other through hydrogen bonds. The ionic strength difference induces no evident structural change of the SMK toxin except that, in the high ionic strength crystal, a number of sulfate ions are electrostatically bound near the basic residues which are also locally distributed at the bottom of the toxin molecule. CONCLUSIONS: The two killer toxins, SMK and KP4, share a unique folding topology which contains a rare structural motif. This observation may suggest that these toxins are evolutionally and/or functionally related. The pH-dependent stability of the SMK toxin is a result of the intensive interactions between the carboxyl groups. This finding is important for protein engineering, for instance, towards stabilization of the toxin molecule in a broader pH range. The present crystallographic study revealed that the structure of the SMK toxin itself is hardly affected by the ionic strength, implying that a high salt concentration affects the sensitivity of the cell against the toxin.

Amino Acid Sequence↗
PubMed1997

Compartmental analysis of asialoglycoprotein receptor scintigraphy for quantitative measurement of liver function: a multicentre study.

A multicentre study on multicompartmental analysis of hepatic scintigraphy using technetium-99m labelled galactosyl serum albumin (GSA), which binds to the asialoglycoprotein receptor, was carried out at seven institutions in Japan. Seventy-four patients with liver disease received 3 mg (185 MBq) of 99mTc-GSA by intravenous injection. Sequential scanning was performed 30 min after injection to obtain anterior images of the heart and liver, followed by single-photon emission tomography (SPET). The indices included in this analysis were hepatic blood flow (Q) and maximal receptor binding rate (Rmax), which showed a good correlation with semiquantitative ratio indices for 99mTc-GSA, namely the retention rate in blood (HH15) and the hepatic uptake rate (LHL15). Q and Rmax also showed a significant correlation with other measures of hepatic function. When patients were grouped according to the severity of chronic liver damage (hepatocellular functional damage), Q was reduced in the moderate and severe groups, while Rmax was reduced in proportion to the functional stage. Both parameters showed no inter-institution difference using analysis of co-variance with the functional stage as a co-variant. With regard to the hepatic uptake rate, anterior planar images and SPET images gave similar results for Q and Rmax. Acquisition times of 15 or 30 min provided the same results. The multicompartmental model analysis permitted comparable results to be obtained at institutions using different gamma cameras, and is therefore considered a universally applicable method. These results indicate that Q and Rmax are useful general indices for evaluating the functional reserve capacity of the liver.

Asialoglycoprotein Receptor↗
PubMed1997

Binding cells of 125I-iodoamphetamine in rat liver.

We recently reported that transrectal or intestinal portal scintigraphy with 123I-iodoamphetamine (IMP) could be a useful method for the non-invasive and quantitative evaluation of the portosystemic shunt in portal hypertension, but what cells in the liver trap IMP has not been clarified. This study was aimed at elucidating whether IMP was extracted by parenchymal cells, sinusoidal endothelial cells, Kupffer cells or fat storing cells. Each type of liver cell was isolated from rats and cultured. The cells were incubated with 125I-IMP and the radioactivity of the lysate was determined. Nonspecific binding was assessed in the presence of an excess of unlabeled IMP, and specific binding was determined by subtracting the nonspecific from total binding. Specific binding observed in parenchymal cells, endothelial cells and Kupffer cells was 70.2 +/- 0.4, 4.2 +/- 1.4 and 2.3 +/- 0.8 pmol/well, respectively, but no specific binding was observed in fat storing cells. The binding in parenchymal cells was much higher than that in endothelial cells or Kupffer cells (p < 0.005). In addition, the binding to parenchymal cells reached equilibrium within 20 min and was not saturable over the concentration range tested (0.5-10 microM). These findings indicate that IMP is mostly extracted by parenchymal cells in the liver.

Amphetamines↗