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Biomedical subjects

T Iida

Publications and source records attributed to T Iida.

At least 397 records · Page 22Linked to original sources
PubMed1988

[MRI findings of cervical cord injury. A case report of long-term follow-up].

A 63 year-old male, who sustained anterior cervical cord injury in a fall on his back during skiing, was consecutively examined by MRI from acute, up to the chronic stage. Right after the fall (2.5 hours later) the injured cord showed high intensity in T2 weighted images. This high intensity area stayed the same up to the chronic stage (6 months later). T1 weighted SE images showed no parenchymal change in the acute stage, but 3 months later a low intensity area appeared in the damaged cord. Thereafter, the injured cord exhibited localized low intensity on T1 weighted images, and high intensity on T2 weighted images, at subsequent MRI examinations. During the course of the examinations no significant neurological recovery was observed. Referring to the findings of our experimental cord injury studies, the high intensity in the T2 weighted images of the acute stage represents hemorrhagic necrotic tissue with edema, while those of the chronic stage suggest myelomalacia, and surrounding gliotic tissue. The low intensity in the T1 weighted images of the chronic stage reflects also this myelomalacia itself. We conclude that MRI of cervical cord injury is a useful diagnostic tool, not only delineating the level of the cord injury, but also aiding in the prognosis.

Follow-Up Studies↗
PubMed1988

[Clinicopathological study of early multicentric gastric carcinomas].

During a two-year period, from August, 1983 to July, 1985, 144 gastric cancer patients have been treated at the National Tohsei Hospital. Among them, 57 patients were determined as having an early gastric carcinoma. Four patients (7.0%) of this number were found to have a multicentric type, 3 manifesting a double II c type, and 1 patient having both a I type and II a type. Pathologically these two types carcinomas were found in only one patient, in a so-called kissing position.

Adenocarcinoma↗
PubMed1988

[Study on changes in plasma platinum concentrations after administration of CDDP to maintenance hemodialysis patients].

Changes in plasma platinum concentration after administration of CDDP were studied in six patients on maintenance hemodialysis with malignancies. Plasma exchange was carried out on three patients for the purpose of plasmapheresis. A therapeutic dose of 51 mg/m2 of CDDP was administered to each patient without any severe adverse reactions. Plasma platinum concentration was measured by atomic absorption spectrophotometry, and the decay curve of the agent showed a biphasic pattern with an initial steep alpha phase and an ensuing mild beta phase in both hemodialysis patients and normal controls. As these patterns showed no renal excretion of CDDP, it was suggested that the uptake of CDDP into tissue was one of the main causes of the steep alpha phase. In patients given plasma exchange one or two hours after the beginning of CDDP administration, the reduction rates of plasma platinum were 74.7-61.7%, but the collection rate of the agent in the exchanged plasma was only 22.2-7.5%. These results indicated that the uptake of CDDP into tissue might occur rapidly within a few hours after CDDP administration.

Adult↗
PubMed1988

Potential bile acid metabolites. 13. Improved routes to 3 beta, 6 beta- and 3 beta, 6 alpha-dihydroxy-5 beta-cholanoic acids.

New synthetic routes to three possible stereoisomers of hyodeoxycholic (3 alpha, 6 alpha-dihydroxy-5 beta-cholanic) acid are described. The principal reactions involved were inversion at C-3 of 3 alpha-hydroxy-6-oxo derivatives with diethyl azodicarboxylate-triphenylphosphine-formic acid and with N,N-dimethylformamide, without allomerization to the more stable 5 alpha form. On the basis of physical and chromatographic data, previously reported 3 beta, 6 alpha-dihydroxy-5 beta-cholanic acid and its methyl ester are shown to be C-3 epimeric mixtures. The 13C nuclear magnetic resonance spectra were of key importance in characterizing the stereoisomers and estimating their purity.

Chemical Phenomena↗
PubMed1987

Detection of toxoplasma IgM antibody by passive latex agglutination reaction.

Three major components (designated Sp-1, -2 and -3) of the microsomal pellet of Toxoplasma gondii (Tp) were isolated by Ultragel AcA 44 gel filtration chromatography from the microsomal pellet solubilized with detergents. Of these, Sp-2 proved to be most reactive with anti-Tp antibodies and its reactivity with IgM and IgG antibodies varied with the concentration at which it was used for sensitizing latex particles. Sp-2 antigen reacted with IgM antibody alone when latex particles were sensitized with less than or equal to 100 micrograms of this antigen/mg of particles, and its reactivity with IgG antibody appeared and increased progressively with increasing sensitizing concentrations of this antigen. Based on this finding, a method of direct measurement of anti-Tp IgM antibody in serum by passive latex agglutination has been developed. Polyacrylamide disc gel electrophoretic analysis of Sp-2 antigen in the presence of SDS revealed four constituents of 43, 35, 28 and 14 kDa. All these components reached with both IgM and IgG when tested by immunoblotting.

Animals↗
PubMed1987

Binding of synthetic beta-human atrial natriuretic peptide to cultured rat vascular smooth muscle cells.

We have studied the effects of synthetic beta-human atrial natriuretic peptide (beta-hANP), an antiparallel dimer of alpha-hANP, on receptor binding and cGMP generation in cultured rat vascular smooth muscle cells and compared the effects with those of alpha-hANP. Characteristics of temperature-dependent binding and degradation of 125I-beta-hANP were similar to those of 125I-alpha-hANP. Scatchard analysis indicated a single class of binding sites for beta-hANP with a maximal binding capacity one-half that of alpha-hANP. Parallel and antiparallel dimers were equipotent in inhibiting the binding and stimulating intracellular cGMP formation, of which the maximal effect was about one-half that of alpha-hANP. Reverse-phase high performance liquid chromatography revealed that most of beta-hANP added to cells was converted to a small molecular mass component corresponding to alpha-hANP after incubation. These data suggest that the less potent effect of beta-hANP in receptor binding and cGMP generation may be partly accounted for by the possible conversion of beta-hANP to alpha-hANP at the site of target cells.

Animals↗
PubMed1987

Effects of steroid and thyroid hormones on synthesis of atrial natriuretic peptide by cultured atrial myocytes of rat.

The in vitro effects of various steroid and thyroid hormones on synthesis of rat atrial natriuretic peptide (rANP) were studied using new-born rat atrial myocytes in culture. Dexamethasone, testosterone and triiodothyronine markedly stimulated both synthesis and secretion of immunoreactive (IR)-rANP with the same peak after 4-day-culture. Dexamethasone and testosterone dose-dependently (10(-7)-10(-6) M) stimulated synthesis of IR-rANP and were the most potent among various steroids tested. Triiodothyronine (T3) also stimulated synthesis of IR-rANP in a dose-dependent manner (10(-8)-10(-7) M), of which effect was more potent than that of tetraiodothyronine, whereas reverse T3 was ineffective. The present study clearly shows that glucocorticoids, androgens and thyroid hormones directly stimulate synthesis of ANP by atrial myocytes and suggests that ANP may play a potential role in mediating and/or modulating the biological effects by these hormones in the cardiovascular system.

Adrenal Cortex Hormones↗
PubMed1987

Capillary gas chromatography of hydroxylated bile acid stereoisomers of the allo and normal series.

Relative retention times and methylene unit (MU) values were determined for 56 bile acids of the allo (5 alpha, A/B-trans) and normal (5 beta, A/B-cis) series, which differ from one another in the number, position and configuration of the hydroxyl groups at positions C-3, C-6, C-7 and/or C-12. The bile acids were derivatized to their methyl ester O-trimethylsilyl ethers (Me-TMS) and methyl ester O-dimethylethylsilyl ethers (Me-DMES), and chromatographed on fused-silica capillary columns, chemically bonded with non-selective OV-1 and selective PEG-20M liquid phases. Of the four possible combinations of derivatives and columns examined, Me-DMES on OV-1 and Me-TMS on PEG-20M were most suitable. The differences in the MU values between the 5 alpha- and 5 beta-series, and between the Me-DMES and Me-TMS ether derivatives, are also summarized. These retention data would be helpful in the identification of closely related bile acid stereoisomers or for estimation of their structures. photolysis.

Bile Acids and Salts↗
PubMed1987

Studies on steroids. CCXXVIII Trace analysis of bile acids by gas chromatography-mass spectrometry with negative ion chemical ionization detection.

A suitable derivatization method for the trace analysis of bile acids by gas chromatography (GC) in combination with negative ion chemical ionization (NICI) mass spectrometry is described. Of various derivatives for the carboxyl group, the pentafluorobenzyl (PFB) ester provided the highest value of the ratio of the negative to the positive ion current. A characteristic carboxylate anion [M - 181]- was produced as the most abundant ion by the loss of the PFB group in NICI. The PFB esters were further derivatized to the dimethylethylsilyl (DMES) ethers, whereby lithocholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and cholic acid were distinctly separated by GC on a cross-linked methyl silicone fused-silica capillary column. The detection limit for the PFB-DMES derivatives of dihydroxylated bile acids was 2 fg when the fragment ion was monitored at m/z 563 in the NICI mode using isobutane as a reagent gas.

Bile Acids and Salts↗
PubMed1987

The detoxification of Bordetella pertussis with glutaraldehyde.

To improve the whole-cell pertussis vaccine we have studied the inactivation of the biological properties characteristic of Bordetella pertussis phase I bacteria, i.e. histamine-sensitizing, lymphocytosis-promoting and mouse protective activities, by treating a concentrated bacterial suspension with various concentrations of glutaraldehyde. Under the experimental conditions, treatment with 10 mM glutaraldehyde at 37 degrees C for 30 min resulted in a marked reduction of the toxic activities without grossly diminishing the protective potency. Further tests were performed on the stability of the protective potency, on the agglutinin production in mice, and on the freedom from abnormal toxicity in guinea-pigs.

Agglutinins↗
PubMed1987

A unique amino acid sequence of the B subunit of a heat-labile enterotoxin isolated from a human enterotoxigenic Escherichia coli.

The purified B subunit of heat-labile enterotoxin produced from a human strain, 240-3, of enterotoxigenic Escherichia coli (LTh(240-3] was carboxymethylated, succinylated, digested with chymotrypsin and subjected to high performance liquid chromatography (HPLC), and the amino acid compositions of the peptide peaks from the column were analyzed and compared with the data reported by Yamamoto and Yokota (J. Bacteriol. 155, 728.1983), who deduced the amino acid sequence of LTh(H10407) from the DNA sequence of a human strain H10407. Only one fraction differed in amino acid composition from that reported by them. This fraction was found to consist of peptides with the sequences Arg-Asn-Thr-Gln-Ile-Tyr and Arg-Ile-Ala-Tyr. Yamamoto and Yokota reported the sequence of the latter peptide as Arg-Ile-Thr*-Tyr, which corresponds to the peptide from 73rd to 76th from amino (N-) terminus. Thus amino acid residue 75 from the N-terminus of LTh-B(240-3) is alanine, not threonine. The B subunit of cholera toxin also has alanine at position 75. LTh(240-3) appeared similar to LTh(H10407) in an Ouchterlony test, vascular permeability test and GMI ganglioside ELISA. These data show that substitution of threonine for alanine at position 75 from the N-terminus does not affect the immunological and biological characteristics of LTh.

Amino Acid Sequence↗
PubMed1987

Autoradiography of alpha- and beta-emitters using a charged-particle imaging system.

A newly developed charged-particle imaging system was applied to rapid measurements of the distribution of alpha- and beta-emitters. The imaging system consists of a ZnS(Ag) screen, two tapered fibers, an image intensifier, and a Polaroid film. The image obtained with the system shows very good quality, namely, a spatial resolution of more than 6 line pairs (lp)/mm and a distortion of less than 2.5%. As the system is capable of detecting each alpha-particle separately, the distribution of alpha-emitters can be quantitatively determined. The autoradiograms of the sections of mice with beta-emitters administered can be obtained with an exposure time of only 2 min compared with 2 weeks by a conventional technique.

Autoradiography↗
PubMed1987

[Psychological studies on accommodation of the eye].

Psychological studies on accommodation are reviewed on the following subjects: (1) subjective and objective methods of measuring accommodation, and their related practical problems in visual experiments, (2) accommodative responses in the absence of an adequate visual stimulus (a resting point of accommodation or a dark focus), and the specific phenomena of night myopia, empty myopia and instrument myopia, (3) contribution of accommodation to the perception of depth and the influence of imagination or thinking of distance on accommodation, (4) unsettled problems on accommodation in the three domains of myopia mentioned above, and the prospect of research in the future, and (5) a description of the results of psychological studies on accommodation that are applied to the establishment of an optimal condition of visual environment.

Accommodation, Ocular↗