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Biomedical subjects

T Konishi

Publications and source records attributed to T Konishi.

At least 37 records · Page 2Linked to original sources
PubMed2001

"Ordered" structure in ionic dilute solutions: dendrimers with univalent and bivalent counterions.

As an intermediate sample of ionic solutes between colloidal particles (macroions) and simple electrolyte ions, we made small-angle x-ray scattering (SAXS) measurements for aqueous solutions of poly(amido amine) dendrimers of three generations (G4, G7, and G10). The SAXS curves of univalent acid solutions showed a single scattering peak, as observed for synthetic macroions. The peak position was dependent on the dendrimer concentration but independent not only of the acid concentration (degree of protonation) but also of the counterion species. The effective charge density of the dendrimer determined by conductivity measurements was found to be insensitive to the acid concentration and the counterion species. The nearest neighbor interparticle distance 2D(exp) calculated from the peak position of the structure factor of G7 and G10 was obviously smaller, though slightly, than the average interparticle distance 2D(0) calculated from molecular weights and concentrations of dendrimers, implying that acid solutions of dendrimers formed the two-state structures by the attractive force. The ultra-small-angle x-ray scattering curve for the hydrochloric acid solution did not show an upturn, which indicates the existence of large scale structural inhomogeneities such as localized ordered structures, probably due to the weak attraction and hence less clear distinction of the ordered and disordered regions. For sulfuric acid solutions, clear scattering peaks were not observed. The bivalent counterions were more strongly associated with the dendrimer ions than the univalent ones. The resulting low charge number of the dendrimers with the bivalent counterion was confirmed directly by the conductivity measurements. These observations confirm that the counterion-mediated attraction does exist even with the univalent counterions and point out that the frequently advanced claim that the effective potential is essentially repulsive with univalent counterions while attraction appears with bivalent counterions is not necessarily correct. It is noted that the intensity of the counterion-mediated attraction in dendrimer solutions is dictated by both the effective charge density and the effective charge number, in contrast with macroionic solutions or colloidal dispersions in which only the effective charge density appeared to be important.

Journal Article↗
PubMed2001

Requirement of ceramide for adhesion of Helicobacter pylori to glycosphingolipids.

Direct adhesion of Helicobacter pylori to immobilized glycosphingolipids (GSLs) was compared to that of their corresponding oligosaccharide-conjugated neoglycoconjugates in order to clarify the roles of the carbohydrate and lipid portions of GSLs in H. pylori adhesion. These bacteria were found to adhere to sulfatide, GM3, GalCer and LacCer, but not to ceramide, sphingomyelin, or polyacrylamides conjugated with beta-galactose, lactose, 3'-sialyllactose or 3'-sulfo-beta-galactose. Furthermore, neoglycolipids or bovine serum albumin derivatives with corresponding oligosaccharides were unable to serve as the ligands. H. pylori adhesion to GalCer with alpha-hydroxyl fatty acid was much stronger than GalCer with the non-hydroxyl fatty acid. These results suggest that H. pylori recognize the conformation of GSL with alpha-hydroxyl fatty acid on solid phase.

Bacterial Adhesion↗
PubMed2001

Iodine L-edge XAFS study of linear polyiodide chains in amylose and alpha-cyclodextrin.

We performed iodine L edge XAFS measurements on blue-black amylose-iodine complex to obtain information about the electronic and geometrical structures of polyiodide chain included in amylose helix. Measurements were also carried out on crystalline alpha-cyclodextrin-iodine complex (alpha-cyclodextrin)2 x Cd0.5 x I5 x 27H2O, in which the polyiodide chain is known to consist of I(5)- unit. It was found that the XANES spectra of these complexes have similar line shapes except for some minor differences, indicating that there are close similarities in the nature of polyiodide chains in these complexes. Besides their similarity, difference in the intensity of the peak at the L1 absorption edge was observed. Its implication for the electronic and geometrical structures is also discussed.

Journal Article↗
PubMed2001

EXAFS analysis of the zinc-binding domain of boar spermatidal transition protein 2.

Boar Spermatidal Transition Protein 2 (TP2; 137 amino acid residues) is supposed to play an important role in initiation of chromatin condensation and cessation of transcriptional activity during mammalian spermniogenesis. Boar TP2 has three potential zinc finger motifs and binds three atoms of zinc per molecule. However the structure of the zinc-binding domain of boar TP2 has not been completely determined. To elucidate the local structure around the zinc atoms of boar TP2, we performed an X-ray absorption fine structure (XAFS) measurement on the zinc-binding domain of TP2(TP2Z)(residues 1-103) in the fluorescence mode. By EXAFS analyses we have demonstrated that each of the three zinc atoms is coordinated by approximately two sulfur and two nitrogen atoms on average. The average Zn-S and Zn-N distances were found to be 2.36 and 2.01 A, respectively. The sulfur and nitrogen atoms are attributed to cysteine and histidine residues, respectively, from comparison of the EXAFS spectra with model compounds ZnS and ZnTPP zinc(II) tetraphenylporphyrin).

Amino Acid Sequence↗
PubMed2001

Simian virus 40 is present in human lymphomas and normal blood.

Many independent studies have demonstrated Simian virus 40 (SV40) in normal and neoplastic human tissues. Clonal integration of virus in the DNA of several thyroid and bone tumors suggests a direct role for SV40 in some cancers. However, in most cases the role of SV40 remains unclear. This study determined the presence of SV40, by amplification followed by hybridization, in 266 normal and neoplastic blood and lymphoid samples. Amplification detected SV40 in 14% of non-autoimmune deficiency syndrome (AIDS) lymphomas, 28% of AIDS related lymphoma and 16% of peripheral blood lymphocytes from non-cancerous patients. No SV40 was detected in leukemia samples. Direct Southern blotting of SV40+ samples detected no virus, consistent with less than one viral genome in ten cells. Sequence analysis of SV40 in blood and lymphoid samples found sequences distinct from laboratory strains of SV40. The presence of limited quantities of SV40 in a small proportion of both normal and neoplastic tissues is suggestive of an adventitious presence with no apparent direct role in blood and lymphoid cancers.

Antigens, Polyomavirus Transforming↗
PubMed2001

Prevalence of positive anticardiolipin antibody in benign infantile convulsion.

We report six anticardiolipin antibody (aCL)-positive cases among 18 children with epilepsy showing various seizure types in our initial study. These six cases revealed normal coagulation tests. As three of these six cases involved benign infantile convulsion (BIC), we further investigated the high frequency of positive aCL-Immunoglobulin (Ig) G in BIC in our subsequent study of nine cases that included three cases from the previous study and an additional six BIC cases followed and/or diagnosed by co-author (T.K.). As a result, eight of nine BIC cases were positive for aCL-IgG and the values of aCL-IgG decreased over long-term observation in three of these cases. The frequency of positivity for aCL-IgG in BIC was obviously higher than that of controls. Based on these results, we suggest that some immunological responses may be responsible for the pathogenesis of BIC.

Adolescent↗
PubMed2001

Age-related volumetric changes of brain gray and white matter in healthy infants and children.

To date there is little information about brain development during infancy and childhood, although several quantitative studies have shown volume changes in adult brains. We performed three-dimensional magnetic resonance imaging (3D-MRI) in 28 healthy children aged 1 month to 10 years. We examined the volumes of whole brain and frontal and temporal lobes with an advanced method for segmenting images into gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) compartments. Growth spurts of whole brain and frontal and temporal lobes could be seen during the first 2 years after birth. During this period the frontal lobes grew more rapidly than the temporal lobes, the right--left asymmetry was more noticeable in the temporal lobes than in the frontal lobes and the increase in GM was larger than that in WM in the temporal lobes. Subsequently, WM volume increased at a higher rate than GM volume throughout childhood. Quantitative information on normal brain development may play a pivotal role in clarifying brain neurodevelopmental abnormalities.

Age Factors↗
PubMed2001

Analysis of the CYP2D6 gene polymorphism and enzyme activity in African-Americans in southern California.

Despite its importance in drug metabolism and disease susceptibility, CYP2D6 activity and genetic polymorphism have rarely been investigated in African-American populations. In order to bridge this gap, we examined the genotype and phenotype of the enzyme in 154 African-American (AA) and 143 Caucasian (C) normal volunteers. AAs are significantly more likely to possess *17 and *5, but less likely to have *4. Overall, the two groups were similar in their CYP2D6 activity as measured with dextromethorphan as the probe (metabolic ratio 2.21 +/- 0.78 for AAs; 2.11 +/- 0.86 for Cs; t = 1.02, NS). Two of four AAs and six of seven Cs were classified as poor metabolizers and have two nonfunctioning alleles. CYP2D6 activity is determined by *17, *4, *5 and age in AAs (r2 = 0.33, f = 18.8, P < 0.001) and by *4 and *XN in Cs (r2 = 0.14, f = 10.8, P < 0.001). These results support previous findings demonstrating the importance of *17 in determining CYP2D6 activity in AAs.

Adult↗
PubMed2001

Characterization of a Ca2+-dependent protein kinase from rice root: differential response to cold and regulation by abscisic acid.

The Ca2+-dependent protein kinases (CDPKs) and abscisic acid (ABA) are known to be involved in low-temperature stress response. The focus of this study was to characterize the 45 kDa protein kinase identified in the crude extract of rice (Oryza sativa L.) seedling roots in response to cold (5 degrees C) stress. The activity of the 45 kDa protein kinase decreased at low temperature as evident by an in-gel kinase assay using histone III-S as a substrate. Also, the Ca2+-dependent activity of this protein kinase was suppressed by cold in the membrane fractions of the root. A general protein kinase inhibitor and Ca2+ chelator inhibited the activity of the 45 kDa protein kinase, suggesting that it was a plant CDPK. The 45 kDa CDPK identified was found to be independent of photosynthetic tissues such as the leaf and leaf sheath of rice seedlings, supporting a direct sensing mechanism in the roots of rice seedlings to cold stress. The suppressed activity of the 45 kDa CDPK was reverted by supplementing with 5 microM ABA under cold stress. The 45 kDa CDPK activity was stronger in the cold-tolerant variety of the 4 types tested than it was in the cold-sensitive one. These results suggest the involvement of endogenous ABA in regulating the activity of the 45 kDa CDPK in response to cold stress.

Abscisic Acid↗
PubMed2001

Anti-tumor-promoting activity of the diterpene from Excoecaria agallocha. II.

Eight new diterpenoids (1-8) have been isolated from the wood of Excoecaria agallocha (Euphorbiaceae) and their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) in Raji cells were examined to search for potent anti-tumor-promoters from natural resources. Of these compounds, the secolabdane-type diterpenoid, compound 7 exhibited a remarkable inhibitory effect on EBV-EA induction, and a significant anti-tumor-promoting effect in the mouse two-stage carcinogenesis test using 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanovl-phorbol-13-acetate.

Animals↗
PubMed2001

Antioxidant potential of qizhu tang, a chinese herbal medicine, and the effect on cerebral oxidative damage after ischemia reperfusion in rats.

A traditional Chinese herbal medicine, Qizhu Tang (QZT) was studied for its in vitro antioxidant activity and the effect on cerebral oxidative damage after forebrain ischemia followed by reperfusion in rats. The QZT decoction was shown to have strong hydroxyl radical (*OH) scavenging activity (approx. 0.1 mM as Trolox equivalent) when determined by ESR using DMPO as a spin trap reagent and H2O2/UV as the *OH source. When the QZT decoction was injected into rat duodenum 2 h before cerebral ischemia, the oxidative brain damage after 45 min reperfusion was strongly inhibited in terms of two biochemical indications, thiobarbituric acid reactive substance formation and the loss of glutathione peroxidase. Since the QZT formula consists of 4 herbal constituents (Rhizoma atractylodis, Poria, Radix notoginseng and Radix astragali), each of the component herbs and their combinations were also examined for their protective effects on the cerebral ischemia/reperfusion injury and the effects were compared with their in vitro antioxidant potential. Although some of the incomplete formulas showed as strong antioxidant activities as complete QZT in vitro, only the complete QZT formula was effective in preventing cerebral oxidative injury in rats, and other preparations showed limited activity in vivo.

Animals↗
PubMed2001

Acid mediated hydrolysis of blueberry anthocyanins.

Acid mediated hydrolysis of anthocyanins was studied using capillary zone electrophoresis (CZE). A commercially available wild blueberry (Bilberry) extract was dissolved in different concentrations of TFA (0.1, 1, 3, 9%), then was subjected to thermodecomposition reaction at 95 degrees C. After the reaction, the samples were analyzed by CZE. The hydrolysis rate of each anthocyanin and the formation of the aglycon were determined by the change in the peak pattern of the anthocyanins in the electropherogram. Each anthocyanin peak decreased time dependently in a first order kinetic fashion. It was revealed that the hydrolysis rate of each anthocyanin was determined primarily by the type of conjugated sugar and not by the aglycon structure. The rate constant of anthocyanin hydrolysis was in the following order, arabinoside>galactoside>glucoside without regard to the aglycon structure. The kinetic behavior of this anthocyanin hydrolysis together with the CZE mobility allowed us to identify an unknown CZE peak as delphinidin 3-O-beta-arabinoside. At low TFA concentration, significant decomposition of the anthocyanidin nucleus occurred, but the glycoside hydrolysis predominated at high TFA concentration. It was further revealed that the aglycon released reacted successively to form polymeric products at higher TFA conditions.

Anthocyanins↗
PubMed2001

Steroidal saponins from Hemerocallis fulva var. kwanso.

Two steroidal saponins, hemeroside A and B, were isolated from the aerial part of Hemerocallis fulva var. kwanso for the first time. The structures of these compounds were established as 24S-hydroxy-neotokorogenin 1-O-alpha-L-arabinopyranosyl 24-O-beta-D-glucopyranoside (1) and isorhodeasapogenin 3-O-beta-D-glucopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside (2) through NMR experiments.

Carbohydrate Sequence↗
PubMed2001

Effect of angiotensin-converting enzyme inhibition on sympathetic tone in patients with mild to moderate heart failure.

Sixteen patients with mild to moderate heart failure were examined to investigate whether sympathetic deactivation plays a role in the improvement in the failing heart by chronic angiotensin converting enzyme (ACE) inhibition. Measurements, including echocardiography, blood examinations, neurohumoral samplings (atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), norepinephrine), and spectral heart rate variability analysis by Holter electrocardiography, were carried out before and 6 months after the administration of lisinopril (5-10 mg/day). Quality of life assessment was accomplished by the Specific Activity Scale (SAS) questionnaire. Treatment with lisinopril for 6 months resulted in a significant reduction in systolic blood pressure. The left ventricular diastolic dimension significantly decreased and fractional shortening significantly increased on echocardiography. Of the 16 patients, 8 had improvement in their symptoms as measured by the SAS. Lisinopril did not significantly reduce the plasma norepinephrine concentration, but there was a significant reduction in the plasma ANP and BNP concentrations. In the heart rate power spectral analysis, total spectral power, high-frequency components and low/high frequency ratios did not change significantly with lisinopril. The mechanism by which ACE inhibitors improve mild to moderate heart failure is not by suppressing sympathetic activity.

Adult↗
PubMed2001

Immediate remission obtained by minocycline in a patient with histiocytic necrotizing lymphadenitis.

A 29-year-old man was admitted because of fever, arthralgia and swelling of the cervical lymph nodes. A diagnosis of histiocytic necrotizing lymphadenitis (HNL) was made based on the findings of a lymph node biopsy. At first, piperacillin sodium (PIPC) was started, but a spiking fever persisted. We therefore changed the PIPC treatment to minocycline. On the following day, his clinical and laboratory findings were dramatically improved. After administering minocycline for 10 days, the HNL symptoms completely disappeared. He has been in good health for 3 years since undergoing treatment. This case strongly indicates that minocycline-sensitive microorganism(s) may be related, at least in part, to the etiology of HNL.

Adult↗