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Biomedical subjects

H Iijima

Publications and source records attributed to H Iijima.

At least 199 records · Page 11Linked to original sources
PubMed1985

Late pulmonary response in guinea pigs after ascaris challenge.

Respiratory resistance of guinea pigs immunized with Ascaris suum was measured over 6 hr after aerosol challenge of the allergen by use of the oscillation method. These animals showed a biphasic pulmonary response to the aerosol challenge with Ascaris suum. Histological analysis of these animals revealed a narrowing of bronchial lumen, peribronchial edema and neutrophil-rich mucous in bronchial lumen at the late pulmonary response.

Aerosols↗
PubMed1985

Two bases are eliminated from DNA by treatment with bleomycin or with hemin-intercalators.

A hemin-intercalator, H4G-His, which possesses 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) as an intercalator moiety and histidine as an intramolecular ligand of the ferrous ion of the hemin ring, cleaves DNA very efficiently, and acts at guanine-pyrimidine sequences preferentially. Bleomycin (BLM) also cleaves DNA with the same base-sequence selectivity shown by H4G-His. The 5'-terminal of the DNA fragments cleaved by H4G-His or by BLM bears a phosphoryl group, while the 3'-terminal of the cleaved DNA fragments does not possess a 3'-phosphoryl group. There are three (or more) kinds of structures of the 3'-terminals. One of the structures of the 3'-terminals of the cleaved DNA fragments is a free 3'-hydroxy group. We propose that there exist plural mechanisms for DNA cleavage by H4G-His or by BLM, one of which involves elimination of two bases from DNA.

Base Sequence↗
PubMed1984

2-Aminodipyrido[1,2-a:3',2'-d]imidazole-porphyrin(Fe) derivatives as sequence specific DNA cleaving reagents.

Some porphyrin (Fe)-intercalators were synthesized. We chose 2-aminodipyrido[1, 2-a:3',2'-d]imidazoles (Glu-P's), which were muta-carcinogens isolated from a pyrolysate of L-glutamic acid, as intercalator moieties. These synthetic porphyrin (Fe)-intercalators cleave DNA at G-C and G-T sequences. The specificity for cleavage of base sequences of DNA is quite similar to that of bleomycin.

Aminopyridines↗
PubMed1984

Rapid off-response and retinal receptor diseases.

A method was described to record the electroretinogram (ERG) in response to off- and on-stimuli, using Ganzfeld light stimulation. The rapid off-response representing the cone response was recorded with the off-stimuli with the light-dark ratio of 10:1 to maintain a constant photopic condition of 1.6 X 10(3) trolands (Zero log unit). The amplitude of the rapid off-response to completely extinguishing the background light was Vo and the amplitude elicited by intermediate intensities of off-stimuli was V. Vo-V was thought to represent the state of the receptor hyperpolarization, and it was correlated with the stimulus intensity (I) by Log (Vo-V) = nLog I + C; n averaged 0.84 +/- 0.15 in 12 normal subjects, and C was a constant. The scotopic b-wave was recorded by on-stimuli with the light-dark ratio of 1:100 and with the intensity less than -2.0 log units. The cone threshold was calculated using the criterion amplitude of the rapid off-response of 10 microvolts. The rod threshold was likewise computed with the criterion amplitude of the scotopic b-wave of 50 microvolts. The cone and rod sensitivities were determined in 5 patients with progressive cone (-rod) dystrophy and in 8 patients with central pigmentary retinal dystrophy. The cone sensitivity was markedly reduced in the former and the rod sensitivity was highly affected in the latter conditions. Separate evaluations of the cone and rod functions by the present technique will be clinically useful.

Adult↗
PubMed1983

Poly(ADP-ribose): structure, quantification, and biological significance.

We have been working on poly(ADP-Rib) since our discovery of it. This lecture will review recent findings on this polymer obtained in our laboratory. Poly (ADP-Rib) has long been thought to be a linear homopolymer attached to nuclear protein. The ribose-ribose bond of poly(ADP-Rib) was shown to be an alpha(1" leads to 2') ribosidic bond. There are two molecular forms of poly(ADP-Rib), namely low molecular weight (L) and high molecular weight (H) poly(ADR-Rib) molecules. The L and H fractions of poly(ADP-Rib) are separable by gel filtration, sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Physicochemically the L and H forms differ in their molecular size, solubility in high salt, rate of hydrolysis by venom phosphodiesterase and circular dichroism (CD) spectrum. However, the two forms have a similar ultraviolet (UV) absorption spectrum, both show a similar hyperchromicity on heating to 98 degrees C or hydrolysis with snake venom phosphodiesterase and give similar results on ordinary chain length determination. The great discrepancy in size observed by physicochemical methods and by the ordinary chain length method indicates the presence of a branching structure in poly(ADP-Rib). The branching structure was proved by demonstrating the presence of a unique compound, 2'[1"-ribosyl-2"(1"'-ribosyl)]adenosine-5',5",5"'-tris(phosphate) and by electron microscopy. The amount of poly(ADP-Rib) was determined by our new method, consisting of tritium labeling and high performance liquid chromatography. The merit of this method is that it can determine the recovery of poly(ADP-Rib) exactly and that its sensitivity is high. The amount of poly(ADP-Rib) changed dramatically when human promyelocytic leukemia cells were induced to differentiate by dimethyl sulfoxide or 12-O-tetradecanoylphorbol-13-acetate. The use of inhibitors of poly (ADP-Rib) polymerase in combination with bleomycin, a DNA damaging antitumor drug, potentiated the antitumor activity of bleomycin against Ehrlich ascites carcinoma cells in vivo.

Animals↗
PubMed1983

Central pigmentary retinal dystrophy and its angiographic classification.

Twenty-one cases of central pigmentary retinal dystrophy were compiled and their clinical features were described. On the basis of fluorescein fundus angiography, these cases were classified into three types according to the changes in the choriocapillaris. In Type 1, the choriocapillaris showed annular or bow-shaped atrophy around the vascular arcade in the posterior pole of the fundus, but little change in the foveal region. Type 2 exhibited round or irregularly shaped atrophy of the choriocapillaris in the center of the posterior pole of the fundus. Type 3 had no atrophy of the choriocapillaris and showed only hyperfluorescence in the posterior pole of the fundus, due to damage of the retinal pigment epithelium. These types differed from each other not only from the morphological point of view, but also in other clinical findings that included age of onset, progression of visual impairment, pattern of color vision defects or recordability of the electroretinogram. It was discussed that central pigmentary retinal dystrophy consists of heterogenous conditions.

Adolescent↗
PubMed1979

A new arylating agent, 2-carboxy-4,6-dinitrochlorobenzene. Reaction with model compounds and bovine pancreatic ribonuclease.

The reagent 2-carboxy-4,6-dinitrochlorobenzene (CDNCB) reacts with the imino, amino and sulfhydryl groups of model compounds. At pH 8.2, sulfhydryl groups react much faster than do amines. N alpha-Acetylhistidine, N alpha-acetyltyrosine and N alpha-acetyltryptophan do not react. Poly(L-Lysine) and poly(DL-lysine) react about 50 times as fast as does N alpha-acetyllysine. A dichloroanalog, 6-carboxy-2,4-dinitro-1,3-dichlorobenzene, shows stepwise reactivity with amines. With bovine pancreatic ribonuclease, which contains no sulfhydryl, CDNCB reacts preferentially with the epsilon-amino of Lys-41 at 450 times the rate with the epsilon-amino of N alpha-acetyllysine. The preferential reactivity at Lys-41 is discussed in relation to the pK of Ly-41, the cationic character of the active site cleft, and the mechanism of RNAase action on substrates.

Amino Acids↗