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Y Kondo

Publications and source records attributed to Y Kondo.

At least 739 records · Page 41Linked to original sources
PubMed1988

Immunoelectron microscopy of the hormonogenic sites of the thyroglobulin molecule.

Hog thyroglobulin was treated with the monoclonal anti-thyroglobulin antibody, 16.3.2, which recognizes the thyroxine residues of thyroglobulin. Size-exclusion high-performance liquid chromatography of the immune complexes indicated that there were 3.5 immunoreactable thyroxine residues/mol of 19 S thyroglobulin. The immune complexes were negatively stained and observed under an electron microscope. Under antigen excess conditions, the complexes were demonstrated as branched chains in which thyroglobulin molecules were linked by antibody molecules. When the antibody was in excess, we found many single thyroglobulin molecules each connecting to 2-3 antibody molecules. Based on the morphology of the immune complexes, we conclude that thyroxine residues are formed preferentially on the molecular surface and localized near both ends of the elongated molecule of 19 S thyroglobulin and possibly at one side of the middle of the molecule.

Animals↗
PubMed1988

Evidence for a preferential iodination site within the thyroglobulin molecule.

Mouse 330 kDa thyroglobulin labeled in vivo was analyzed using a tryptic peptide mapping technique and high performance liquid chromatography (HPLC). 30 min after Na125I injection, one peptide spot (spot 7) on a silica gel plate was the only prominent labeled peptide, followed by other labeled peptide spots after 1 h. HPLC showed that spot 7 was rich in monoiodotyrosine. The ratios between the iodoamino acids were strictly maintained from 1 to 6 h after Na125I injection. Spot 7 was again the first spot that appeared from the samples of iodine-deficient mice. These data indicate that there is some preferential iodination site(s) within the thyroglobulin molecule and also that their iodoamino acid composition is predetermined.

Amino Acids↗
PubMed1988

Preferential formation of triiodothyronine residues in newly synthesized [14C]tyrosine-labeled thyroglobulin molecules in follicles reconstructed in a suspension culture of hog thyroid cells.

Early processes of thyroid hormone (T4 and T3) synthesis in thyroglobulin molecules were studied using follicles reconstructed in a primary culture of hog thyroid cells under the influence of TSH. When the reconstructed follicles were incubated with 14C-tyrosine, thyroglobulin containing the labeled tyrosine was newly synthesized and in the presence of iodide, some of the labeled tyrosine residues were iodinated and coupled to produce labeled iodothyronines, T4 and T3. Coupling efficiency, especially the efficiency of T3 production, was much higher than that obtained from the average iodoamino acid composition of mature thyroglobulin from the gland, indicating a preferential iodination of hormonogenic tyrosines and synthesis of T3. The total production of T3 was higher than T4 under the present conditions. However, free labeled T4 released into the medium was more than T3 after 16 h incubation of the labeled follicles with non-labeled tyrosine, suggesting the preferential liberation of T4 from the labeled peptide and/or release from the cells.

Animals↗
PubMed1988

A histopathologic study of 102 cases of intrahepatic cholangiocarcinoma: histologic classification and modes of spreading.

In our survey of 102 cases of intrahepatic cholangiocarcinoma, 71 peripheral type cases and 31 hilar type cases were observed, the former being prone to metastasize to remote organs and lymph nodes when compared with the latter. These cases were histologically classified into nine histologic types according to the predominant features and rearranged into three groups (well-differentiated, less-differentiated, and uncommon). Although most of these cases were mucin-producing adenocarcinomas with variable grades of differentiation (92 of 102; 90%), several uncommon types were also encountered (ten of 102; 10%), such as adenosquamous, squamous, mucinous, or anaplastic carcinoma. Remote organ metastases were observed more frequently in the less-differentiated group than in the well-differentiated group. In regard to intrahepatic tumor spreading, expansion via sinusoidal spaces (93%), vascular (52%) or lymphatic (18%) involvement, perineural invasion (16%), replacing growth in the bile duct (12%), and permeation in the portal connective tissue (19%) were observed. The cholangiocarcinomas with the vascular involvement presented a higher tendency of intrahepatic as well as extrahepatic metastasis. For correct diagnosis and treatment of cholangiocarcinoma, it seems to be important to possess some knowledge of these histologic types, including their variations and patterns of intrahepatic spread.

Adenoma, Bile Duct↗
PubMed1988

Reevaluation of contribution of physical fitness, body weight, and different sports activity to resting blood pressure in young men.

The purposes of the present study were to evaluate the relationship between resting blood pressure and maximal oxygen uptake (VO2max) and to elucidate the association of different types of sports activity on the resting blood pressure in Japanese young men with a wide range of VO2max. The subjects (n = 46) consisted of untrained subjects (n = 24), judo athletes (n = 11), and triathletes (n = 11) aged 21 to 35 years. Systolic (SBP) and diastolic (DBP) blood pressures were measured in the sitting position after 5 min of resting, and VO2max was directly measured by the Douglas bag method. SBP, DBP, and mean blood pressure (MBP) were negatively correlated with VO2max and positively correlated with body weight. A stepwise selective multiple regression analysis for SBP resulted in two significantly correlating variables: VO2max and body weight. For DBP and MBP, the analysis resulted in two explaining variables: VO2max and body weight. Two independent variables explained 37% of the variation of the SBP, 43% of that of DBP, and 54% of that of MBP. These results indicate that variance in resting blood pressure is partly accounted for by the variance in endurance capacity (i.e., VO2max). However, SBP, DBP, and MBP were significantly higher in judo athletes compared with untrained men (P less than 0.05) when it was compared with the same range of VO2max. These results indicate that resting blood pressure is probably influenced with VO2max, while the relationship is influenced by the type and intensity of training and other factors.

Adult↗
PubMed1988

Combined hepatocellular-cholangiocarcinoma with variable sarcomatous transformation.

An adult case of combined hepatocellular-cholangiocarcinoma with variable sarcomatous changes is presented. Histologically, the tumor was composed of hepatocellular carcinoma, cholangiocarcinoma, and sarcomatous portions, including spindle-shaped, pleomorphic, and osteoplastic varieties. There was a transitional cell form between the carcinoma and sarcomatous cells. These tumor elements showed both independent and concurrent metastases. Immunohistochemical examination for keratin revealed positive staining in the tumor cells except for osteoplastic immature cells, whereas vimentin had positive results only in some sarcomatous cells. On the basis of these findings, the possibility of sarcomatous transformation of combined hepatocellular-cholangiocarcinoma was discussed.

Adenoma, Bile Duct↗
PubMed1988

Chemical modifications of histidyl and tyrosyl residues of inorganic pyrophosphatase from Escherichia coli.

Chemical modifications by photooxidation in the presence of rose bengal (RB) and with tetranitromethane (TNM) were carried out to elucidate the amino acid residues involved in the active site of inorganic pyrophosphatase (pyrophosphate phosphohydrolase) [EC 3.6.1.1] from Escherichia coli Q13. The photooxidation caused almost complete inactivation, which followed pseudo-first-order kinetics depending on pH and concentration of RB. The presence of Mg2+ or complex between Mg2+ and substrate or substrate analogues, imidodiphosphate and sodium methylenediphosphate, gave partial protection against the photoinactivation, whereas the substrate alone showed no protective effect. The enzyme was almost completely inactivated by chemical modification with TNM, depending upon the concentration of TNM. The amino acid analyses and enzyme activity measurements revealed that 2 histidyl residues among 5 photooxidized residues and 2 tyrosyl residues per subunit were essential for the enzyme activity. The circular dichroism (CD) spectra in the far ultraviolet region showed no significant alteration during these two modifications, indicating that the polypeptide chain backbone of the enzyme remained unaltered. However, the modifications altered considerably the CD bands in the near ultraviolet region and the fluorescence spectra, indicating that subtle change in conformation had occurred in the vicinity of the active site in the enzyme molecule. These results strongly suggest that histidyl and tyrosyl residues may be involved in the active site or be located in the vicinity of the active site and seem to participate in the mechanism of stability against heat inactivation.

Binding Sites↗
PubMed1988

Interaction between chicken gizzard caldesmon and tropomyosin.

Chicken gizzard muscle caldesmon has been examined for ability to interact with tropomyosin from chicken gizzard muscle by using fluorescence enhancement of tropomyosin labeled with dansyl chloride (DNS) and affinity chromatography. The binding of caldesmon to tropomyosin was regulated by Ca2+ and calmodulin, i.e., at low ionic strength most of the caldesmon bound to tropomyosin-Sepharose 4B was co-eluted by adding calmodulin only in the presence of Ca2+, but not in its absence. This regulation by Ca2+ and calmodulin was also suggested by fluorescence measurements. Actin- and calmodulin-binding sites on the caldesmon molecule were located in the 38K fragment (Fujii, T., Imai, M., Rosenfeld, G.C., & Bryan, J. (1987) J. Biol. Chem. 262, 2757-2763). When 38K-enriched fraction was applied to the tropomyosin-Sepharose, the 38K fragment was retained by the column and could be eluted by adding Ca2+ and calmodulin.

Animals↗
PubMed1988

Effect of Ca2+ on Cl- transport in thin ascending limb of Henle's loop.

Effects of ambient Ca2+ concentration on Cl- transport across the thin ascending limb of Henle's loop (TAL) were examined by the in vitro microperfusion technique. When Ca2+ concentration in the bathing fluid was decreased from 1.5 mM to nominally 0 mM at 37 degrees C, the relative permeability of Cl- to Na+ (PCl/PNa) estimated from the NaCl diffusion voltage changed from 2.44 +/- 0.20 to 1.27 +/- 0.16 (n = 7, P less than 0.01). When Ca2+ concentration of the luminal fluid was reduced, PCl/PNa was unchanged. When Ca2+ concentration in the bathing fluid was changed from 4.5 to nominally 0 mM, the lumen-to-bath flux coefficient for 36Cl (K36Cl(l----b)) was decreased, whereas the value for 22Na was unchanged, indicating that the reduction of Ca2+ concentration in the bathing fluid selectively inhibits Cl- transport without affecting Na+ transport. By contrast, at 23 degrees C, the elimination of Ca2+ from the bathing fluid caused only a small reduction of PCl/PNa. Although at 23 degrees C acidification of the bathing fluid caused only little or no decrease in Cl- permeability, the elimination of Ca2+ from the bathing fluid under acid pH markedly suppressed the (K36Cl(l----b)) (10(-7) cm2/s). The pH titration curves of relative Cl- permeability examined at three different Ca2+ concentrations at 37 degrees C revealed that the interaction between proton and Ca2+ was noncompetitive. Addition of quin 2-AM, which reduced intracellular Ca2+ concentration, to the bath caused an irreversible suppression of Cl- permeability, suggesting that the decrease in intracellular Ca2+ concentration also inhibits the Cl- transport across the TAL.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1988

Evidence for conductive Cl- pathways across the cell membranes of the thin ascending limb of Henle's loop.

To examine whether Cl- is transported via transcellular pathways in the thin ascending limb of Henle's loop (TAL), conventional microelectrode technique was applied in isolated TAL segments of hamsters perfused in vitro. The average basolateral membrane voltage (VB) was -24.5 +/- 1.5 mV (n = 18). Ouabain (10(-4) M) had no effect on VB. Sudden reduction of basolateral Cl- concentration from 165 to 5 mmol/liter caused a large depolarizing spike (+49.1 +/- 2.7 mV, n = 18), while the transepithelial potential (VT) showed lumen positive deflection by 33.4 +/- 1.2 mV, which indicates that a large Cl- conductance exists in the basolateral membrane. Reduction of luminal Cl- concentration caused sustained depolarization of luminal cell membrane from +24.5 +/- 2.1 to -9.7 +/- 3.4 mV (n = 6), which indicates that there is also a Cl- conductance in the luminal membrane. Since we have previously shown that acidification of ambient solution suppresses the transmural Cl- permeability, we tested whether acid pH also inhibits the Cl- conductance of the basolateral membrane. When pH of the bathing fluid was lowered to 5.8, the depolarizing spike of VB and the change of VT upon sudden reduction of basolateral Cl- were almost completely abolished. From these results we conclude: (a) both the luminal and the basolateral membrane of hamster TAL segments have Cl- conductances, and (b) Cl- transport in the TAL takes place, at least in part, via a transcellular route when a transepithelial Cl- gradient is present.

Animals↗
PubMed1988

Inhibition by islet-activating protein, pertussis toxin, of P2-purinergic receptor-mediated iodide efflux and phosphoinositide turnover in FRTL-5 cells.

Exposure of FRTL-5 thyroid cells to ATP (1 microM to 1 mM) resulted in the stimulation of I- efflux in association with the induction of inositol trisphosphate production and intracellular Ca2+ mobilization. Nonhydrolyzable ATP derivatives, ADP and GTP, were also as effective in magnitude as ATP, whereas neither AMP nor adenosine exerted significant effect on I- efflux, suggesting a P2-purinergic receptor-mediated activation of I- efflux. Treatment of the cells with the islet-activating protein (IAP) pertussis toxin, which ADP-ribosylated a 41,000 mol wt membrane protein, effectively suppressed the phosphoinositide response to ATP in addition to ATP-dependent I- efflux at agonist concentrations below 10 microM. In contrast, the I- efflux stimulated by TSH, A23187, or phorbol myristate acetate was insusceptible to IAP. The IAP substrate, probably GTP-binding protein, is hence proposed to mediate the activation of P2-purinergic receptor-linked phospholipase-C in FRTL-5 cells. However, the responses to ATP, its nonhydrolyzable derivatives, or ADP at the higher agonist concentrations, especially above 100 microM, were only partially inhibited by IAP, even though the IAP substrate was totally ADP ribosylated by the toxin. The responses to GTP in the whole concentration range tested were not influenced by IAP treatment. Thus, signals arising from the P2-receptor might be transduced to phospholipase-C by two different pathways, i.e. IAP-sensitive and insensitive ones, and result in the stimulation of I- efflux.

Adenine Nucleotides↗
PubMed1988

Ultrasonic evaluation of cervical metastatic lymphadenopathy.

We investigated the location, size, and shape of cervical lymph nodes in head and neck cancer, using a 7.5-MHz ultrasound scanner. First, the different criteria for normal size were obtained for cervical lymph nodes in each region; lymph nodes greater than 9 mm in thickness in the internal jugular chain or greater than 7 mm in thickness in the submandibular and submental chains should be suspected of harboring metastatic foci. Second, metastatic nodes showed a more rounded configuration than nonmetastatic ones. Third, a comparative study of metastatic lymph nodes between the in vivo and in vitro ultrasonograms and the corresponding histopathological findings disclosed that an echogenic region in an ultrasonogram of a metastatic node was caused by coagulation necrosis, and a cystic area of liquefaction necrosis.

Carcinoma, Squamous Cell↗