PubMed Health⌕ Search

Biomedical subjects

T Takayasu

Publications and source records attributed to T Takayasu.

82 records · Page 5Linked to original sources
PubMed1981

Complete amino acid sequence of the Fc region of a human delta chain.

The complete amino acid sequence of an Fc-like fragment designated Fc delta (t) and obtained by limited proteolysis with trypsin of an intact myeloma IgD protein (NIG-65) has been determined. The fragment contains 226 amino acid residues and has a molecular weight of 32,000 per monomeric unit. It has three glucosamine oligosaccharides at asparagine residues 68, 159, and 210. Of these, glucosamine-159 is characteristic of the delta chain and has no counterpart position in any of the other classes. On the other hand, glucosamine-68 is shared by gamma, mu, and epsilon, and glucosamine-210 is shared by alpha and mu. Although the Fc delta (t) has the common framework structure of immunoglobulins, its sequence has many individual characteristics when its two domains are compared separately with the counterpart domain of other heavy chains. Such comparison has shown that the two Fc domains of the delta chain should be placed in an independent branch in topology; for all the other classes, the Fc domains are paired well with their counterparts. The comparison has also shown that there are three prominent gaps by which each domain can be divided into two homologous halves. For each class of immunoglobulin, a moderate degree of internal homology exists between the first half and the second half of each domain of the Fc, suggesting that the primordial gene may have coded for a unit about the size of a half domain. Based on this observation together with sequence comparisons, a possible genetic mechanism is proposed for the origin and evolution of the genes for immunoglobulin domains.

Amino Acid Sequence↗
PubMed1981

Comparative studies on the structure of the light chains of human immunoglobulins. III. Amino acid sequence of a lambda type Bence Jones euglobulin.

Amino acid sequence analysis has been done on a euglobulin-like lambda Bence Jones protein NIG-58 with the major objective of determining the sequence of the variable region. Twenty-seven tryptic peptides with 4 overlapping peptides covering 215 residues, were isolated from completely reduced and aminoethylated protein, and 19 of these were completely sequenced. These comprised the entire variable region and 8 from the constant region. For the remaining peptides covering the rest of constant region, only partial sequences or the amino acid composition were determined. All the tryptic peptides could be arranged in order on the basis of the above results and homology with other lambda chains of known sequences. The sequence of the variable region (residues 0-108) differed from those previously reported in 30 to 50 residues and was classified into the V lambda II subgroup, but no variation was found in the sequence of the last 105 residues. The protein is characteristic of euglobulin and has 2 additional half cystine residues at positions 26 and 28, which forms covalent polymers up to octamer when kept in an alkaline solution.

Amino Acid Sequence↗
PubMed1979

Comparative study on the structure of the light chains of human immunoglobulins. II. Assignment of a new subgroup.

The primary structure of the variable region of the human lambda type Bence Jones protein NIG-48 was determined by analysis of the N-terminal sequence of the completely reduced and aminoethylated protein, as well as of five cyanogen bromide fragments. The variable region of NIG-48 contains 112 amino acid residues. The protein NIG-48, having a unique sequence of the variable region, a low degree of homology (about 50%) with lambda chains of the five other subgroups and the addition of two residues around 65, may represent a new subgroup, namely V lambda VI.

Amino Acid Sequence↗
PubMedDate not supplied

Liver resection for hepatocellular carcinoma (HCC) with direct removal of tumor thrombi in the main portal vein.

Since the tumor thrombus in the main portal vein appears in the terminal stage of hepatocellular carcinoma (HCC), any attempt to remove it surgically is thought to be impractical as the malignancy itself cannot be entirely removed. During the past 5 years, we have performed tumor thrombectomy combined with hepatectomy in 29 of 298 patients with HCC. This combined therapy was initially decided upon as an emergency measure to prevent impending rupture of esophageal varices, rather than to improve patient survival. Since portal flow was obtained after removal of thrombi, this condition enabled transcatheter arterial embolization (TAE) and/or percutaneous ethanol injection therapy (PEIT). Although improved patient survival was not the primary goal of the emergency operation and there was an operative mortality of 11%, half of the other patients in the present series had unexpectedly high survival rates of 1 year (52.2%), 2 years (23.2%), and 3 years (11.6%), which were significantly higher than in patients not undergoing operation (n = 22).

Aged↗
PubMedDate not supplied

Determination of the volatile anesthetics halothane, enflurane, isoflurane, and sevoflurane in biological specimens by pulse-heating GC-MS.

Four kinds of volatile anesthetics (halothane, enflurane, isoflurane, and sevoflurane) that were dissolved in 3 microL of experimental plasma samples were examined by the pulse-heating gas chromatographic-mass spectrometric method, and this approach was found to be reliable for qualitative and quantitative analysis. The analytical results also showed good recovery and accuracy. This method was then applied to real blood specimens taken from patients during surgery. The same blood specimens were also analyzed simultaneously by the conventional headspace method for comparison. The data for the clinical blood specimens examined by these two methods showed reasonable correlation coefficients of 0.914 (enflurane) and 0.937 (sevoflurane). These results indicate that the pulse-heating method is applicable for toxicological and clinical analysis of several kinds of volatile anesthetics.

Adult↗
PubMedDate not supplied

A physiologically based pharmacokinetic model for (-)-quinuclidinyl benzylate using nonlinear irreversible tissue binding parameters in rats.

The disposition characteristics of (-)-quinuclidinyl benzylate (QNB) were investigated in rats, and a physiologically based pharmacokinetic model was established using its linear and nonlinear tissue binding parameters. The steady-state distribution volume (Vdss) and systemic clearance (CLtot) were comparable after iv administration of 325 ng/kg and 3.2 mg/kg, suggesting that QNB pharmacokinetics based on plasma concentrations is linear. However, tissue accumulation was observed in the heart, lung, muscle, and brain. This accumulation persisted for over 12 hr after the iv administration of 325 ng/kg [3H]QNB. Tissue binding parameters were determined after continuous infusion of QNB. Irreversible and nonlinear binding parameters were obtained in various regions of the brain and other tissues. Reversible equilibrium concentration ratios between tissue and plasma were determined after high-dose infusion. QNB concentrations in the plasma, heart, lung, muscle, and brain were predicted after the administration of 325 ng/kg or 3.2 mg/kg. There was reasonable agreement between the model predictions and the observed data.

Animals↗