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Biomedical subjects

H Iijima

Publications and source records attributed to H Iijima.

At least 181 records · Page 10Linked to original sources
PubMed1988

A new perimetric color vision analyzer.

A new apparatus was developed for mapping the extrafoveal color vision, the perimetric color vision analyzer. A yellow test object with varying degrees of saturation is presented on a cathode ray tube color display in a random sequence at one of 10 points around the fixation spot. The background is a mosaic pattern consisting of gray spots of the same size and shape as the test object, with various luminances. Background patterns with or without a test object are presented alternately. The subject is instructed to press a key when he detects a yellow object in the background pattern. The luminance of the test object is in the same range as the background gray spots. Since the luminance of background spots is changed synchronously at random when the test object appears, the subject can detect the test object only by the difference in color saturation. The results show the color contrast sensitivity at every designated point in the central visual field. The clinical application of the perimetric color vision analyzer revealed extrafoveal color defects which could not be evaluated with conventional color vision tests. It also showed that in some chorioretinal and optic nerve disorders the topographic pattern of color contrast sensitivity disagrees with that of luminance contrast sensitivity measured with automated static perimetry.

Adult↗
PubMed1987

Calibration of effective van der Waals atomic contact radii for proteins and peptides.

Effective van der Waals radii were calibrated in such a way that molecular models built from standard bond lengths and bond angles reproduced the amino acid conformations observed by crystallography in proteins and peptides. The calibrations were based on the comparison of the Ramachandran plots prepared from high-resolution X-ray data of proteins and peptides with the allowed phi, psi torsional angle space for the dipeptide molecular models. The calibrated radii are useful as criteria with which to filter energetically improbable conformations in molecular modeling studies of proteins and peptides.

Chemical Phenomena↗
PubMed1987

Purification and properties of dihydrogeodin oxidase from Aspergillus terreus.

The last step of (+)-geodin biosynthesis is a phenol oxidative coupling, which is one of the most important reactions in biosynthesis of natural products. The enzyme named dihydrogeodin oxidase catalyzes the regio- and stereospecific phenol oxidative coupling reaction to form (+)-geodin from dihydrogeodin. The enzyme was purified from the cell-free extract of Aspergillus terreus, a (+)-geodin producer, by ammonium sulfate fractionation, acid treatment, and column chromatographies on DEAE-cellulose, Hydroxyapatite, chromatofocusing, and Toyopearl HW-55S. The purified enzyme was homogeneous as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 153,000 by gel filtration on a Toyopearl HW-55S column and 76,000 by SDS-polyacrylamide gel electrophoresis, indicating that the enzyme is a dimer. The purified enzyme showed an intense blue color and had absorption maxima at 280 and 600 nm, which suggested it to be a blue copper protein. The copper content was found to be 8 atoms per subunit by atomic absorption analysis and no significant amount of other metals was detected by ICP emission spectrometry. The electron paramagnetic resonance spectrum showed the presence of type 1 and type 2 copper atoms in the enzyme molecule. Sodium azide and ethylxanthate inhibited the enzyme activity, but potassium cyanide and diethyldithiocarbamate, both known as potent copper enzyme inhibitors, were not inhibitory.

Aspergillus↗
PubMed1987

Molecular cloning and expression in Escherichia coli of a cDNA encoding human pancreatic elastase 2.

We have cloned a DNA that is complementary to the messenger RNA that encodes human pancreatic elastase 2 from a human pancreatic cDNA library using a cloned cDNA for rat pancreatic elastase 2 messenger RNA. This complementary DNA contains the entire protein coding region of 807 nucleotides which encodes preproelastase of 269 amino acids, and 4 and 82 nucleotides of the 5'- and 3'-untranslated sequences, respectively. When this deduced amino acid sequence was compared with known amino acid sequences it showed 82% homology with rat pancreatic elastase 2. This deduced sequence also contains a 16-amino-acid peptide identical with the N-terminal sequence determined for native human pancreatic proelastase 2. Taking the above findings together, we conclude that the cloned cDNA encodes a mature enzyme of 241 amino acids including 16 and 12 amino acids for a signal peptide and an activation peptide, respectively. Moreover, the predicted key amino acid residues involved in determining the substrate specificity of mammalian pancreatic elastase 2 are retained in the human enzyme. Cloned human pancreatic elastase 2 cDNA was expressed in E. coli as a mature and pro-form protein. Both resulting proteins showed immunoreactivity toward anti-elastase serum and enzymatic activity. We have also cloned and sequenced a porcine pancreatic elastase 2 cDNA.

Amino Acid Sequence↗
PubMed1987

Bronchoalveolar lavage and histologic characterization of late asthmatic response in guinea pigs.

To elucidate the mechanisms of late asthmatic response (LAR) observed in asthmatic subjects, we have developed an animal model of LAR using guinea pigs. Fifty guinea pigs were immunized with a mixture of Ascaris suum extract and aluminum hydroxide and then challenged with an inhalation of Ascaris suum extract without anesthesia. Twenty of the 50 guinea pigs showed a dual asthmatic response in which the LAR occurred 3 to 6 h after immediate asthmatic response (IAR). Histologic studies by rapid freezing with liquid nitrogen or bronchoalveolar lavage (BAL) were performed in 14 of these 20 guinea pigs with LAR and compared with those in 10 of 18 guinea pigs with only IAR, 10 control guinea pigs, and 10 nonimmunized but challenged guinea pigs. Both the percentage and the absolute number of neutrophils in the BAL fluid of the guinea pigs with LAR were significantly greater than those of the control guinea pigs (p less than 0.02) and than those of the nonimmunized but challenged guinea pigs (p less than 0.02). However, that of guinea pigs with LAR was not significantly different from that of guinea pigs with only IAR. On the other hand, histologic examination showed that eosinophil infiltration within the airway walls of the guinea pigs with LAR was more prominent than that of the guinea pigs with only IAR, and showed that there was no significant difference in neutrophil infiltration within the airway walls between the guinea pigs with LAR and the animals with only IAR. Contraction of airway (bronchus, bronchiole) smooth muscle, submucosal edema, and mucus in airway lumen were also observed in LAR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The pathogenesis of experimental arteritis induced by Candida alkali-extract in mice.

The pathogenesis of experimental arteritis induced by Candida alkali-extract in mice was studied from the immunological, pharmacological and chemical points of view. The following results were obtained. 1) The incidence of arteritis increased in parallel with IgE antibody level of Candida, as shown by the PCA method. 2) Candida polysaccharide showed cardiotonic, coronary vasodilatatory and vasoconstrictive activities on Langendorff's and spiral preparation of rats. 3) Candida polysaccharide was shown to contain digitoxose by gas-mass spectrometry. From these results, it is suspected that this extract reacts on experimental animals by the toxic and immunological mechanisms, and that these mechanisms may be related to the occurrence of arteritis.

Animals↗
PubMed1987

[Non-invasive secretory carcinoma of the breast].

A case of non-invasive secretory carcinoma of the breast is reported. The patient was a 33-year-old Japanese woman who complained of abnormal nipple discharge from the right breast. Although physical and radiological examinations failed to find any abnormal nodular lesions in the breast, a cytological examination revealed signet-ring-like atypical cells in the smears of nipple discharge. Radical mastectomy with axillary lymph nodes dissection was performed. No nodular lesions were macroscopically observed. However, intraductal proliferation of atypical cells was microscopically found in the excised breast. Diastase-resistant PAS-positive mucus was observed in the tumor-cell-forming-lumina and in the cytoplasm of tumor cells. No metastases were observed in the axillary lymph nodes.

Adult↗
PubMed1986

Functional analogues of bleomycin: DNA cleavage by bleomycin and hemin-intercalators.

New hemin-intercalators (Hem-G's) that cleave DNA were synthesized, on the basis of 2-amino-6-methyldipyrido[1,2-alpha:3',2'-d]imidazole (Glu-P-1) as an intercalator moiety. Hem-G's, which possess an intramolecular ligand of the ferrous ion (a histidine or imidazole moiety), cleave DNA very efficiently and act at guanine-pyrimidine sequences preferentially. Bleomycin (BLM) also cleaved DNA with the same base-sequence selectivity shown by Hem-G's. The 5'-terminus of the DNA fragments cleaved by Hem-G's or by BLM is a phosphoryl group, while the 3'-terminus of the cleaved DNA fragments does not possess a 3'-phosphoryl group. There are more than three kinds of 5'-end 32P-labeled DNA fragments, which can be substrates of terminal deoxynucleotidyl transferase (TdT). One of the 3'-termini of the cleaved DNA fragments is a 3'-hydroxy group. The mobility of the 3'-end 32P-labeled DNA fragment cleaved by Hem-G's or by BLM corresponds to the removal of pyrimidine bases having guanine at the 5'-side. The mobility of one kind of the cleaved 5'-end 32P-labeled DNA fragments corresponds to the removal of guanine having pyrimidine at the 3'-side, followed by 3'-dephosphorylation. We propose that there exist plural mechanisms for DNA cleavage by Hem-G's or by BLM. The deduced structures of the cleaved DNA fragments suggest that one of the mechanisms involves deletion of two nucleotide units from DNA.

Base Sequence↗
PubMed1986

Effects of retinal detachment surgery on standing potential.

We studied the effects of retinal detachment surgery on the standing potential of the human eye using the electrooculographic technique. Before and two weeks after surgery, we measured the relative base value (rBV) which is the base value of the affected eye divided by the base value of the fellow eye. The rBV distributed around 1.0 before surgery and decreased below 1.0 two weeks after surgery. The change in the rBV through surgery represented by the value R is defined as preoperative rBV minus postoperative rBV divided by preoperative rBV; this was closely correlated with the area of the scleral buckling. The decrease in the rBV was thought to represent the reduction in the standing potential of the operated eye, probably due to circulatory disturbance of the choroid.

Adolescent↗