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Biomedical subjects

M Iijima

Publications and source records attributed to M Iijima.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of biliary excretion of indocyanine green by the thiol-oxidizing agent, diazenedicarboxylic acid bis[N,N'-dimethylamide].

Biliary excretion of Indocyanine green (ICG) in Sprague-Dawley rats during constant intravenous infusion of the dye in vivo was inhibited by intraperitoneally administered diazenedicarboxylic acid bis[N,N'-dimethylamide] (diamide, 0.5 mmol/kg body wt), a glutathione-specific thiol-oxidizing agent. Significant inhibition of ICG excretion was observed also when ICG was injected rapidly 90 min after diamide administration. Disappearance of ICG from the plasma was not affected by diamide. Oxidized glutathione in bile increased transiently following diamide administration but returned to the basal level within 30 min. Hepatic concentrations of reduced and oxidized glutathione were not different from those of controls when determined 90 min after diamide administration. The inhibition of ICG excretion was completely prevented by subsequent administration of dithiothreitol (0.5 mmol/kg) 30 min after that of diamide. The results, therefore, suggest that the biliary excretion of ICG was inhibited by secondary changes in the redox status of thiols in hepatocytes caused by a transient increase in oxidized glutathione.

Animals↗
PubMed1992

Effects of F- on apatite-octacalcium phosphate intergrowth and crystal morphology in a model system of tooth enamel formation.

In order to study the effect of F- on tooth enamel-like apatite formation, crystal growth experiments were carried out in the presence of 0.1 approximately 2 ppm F- at 37 degrees C and at pH 6.5 in a model system of enamel formation where octacalcium phosphate (OCP) was stable. Morphology changed from long and thin ribbons to small needle-like plates, and the product changed from OCP to apatite with an increase in F- concentration. In the presence of 0.1-1 ppm F-, apatite-OCP intergrowth took place, and crystals composed of apatite and OCP lamellas were formed. These crystals showed long and thin plate-like morphology and embeded an OCP lamella in the center of the crystal. The OCP lamella and its (100) planes were parallel to the (100) planes of apatite. The thickness of OCP decreased and that of apatite increased with an increase in F- concentration. Some apatite crystals obtained at 1 ppm F- embedded a central plane instead of the distinct OCP lamella. The result indicates that initially formed, thin, plate-like OCP acted as a template for the subsequent epitaxial overgrowth of apatite and, moreover, F- played an important role in regulating the apatite-OCP intergrowth.

Apatites↗
PubMed1992

The relationship between biliary secretion of bilirubin and glutathione in the rat.

The relationship between biliary secretion of bilirubin and glutathione was investigated by infusing bilirubin solution (200 nmol/min/100 g body wt) into Sprague-Dawley rats and measuring bilirubin and glutathione in the bile. Hepatic glutathione level, when modified between the range of 1-10 mumols/g liver wt, did not affect biliary maximal secretory rate (Tm) of bilirubin (80 nmol/min/100 g body wt). However, when biliary secretion of bilirubin exceeded 10 mM or 30 nmol/min/100 g body wt, biliary secretion of glutathione was markedly impaired while the bile flow remained relatively constant. Thus, bilirubin impaired the biliary secretion of glutathione selectively compared to its effect on bile formation. The results indicate that the mechanisms of biliary secretion of the two physiological substances, bilirubin and glutathione, are closely related.

Animals↗
PubMed1992

A case of neutrophilic dermatosis (ND) complicated by cryofibrinogenemia (CFGN) and myelodysplastic syndrome (MDS).

A case of neutrophilic dermatosis (ND) complicated by cryofibrinogenemia (CFGN) and myelodysplastic syndrome (MDS) is reported. Although the patient presented pancytopenia, the skin lesions were compatible with those of ND from the clinical and histopathological findings. Further, immunofluorescence technique revealed cryofibrinogen (CFG) deposits on the walls of the blood vessels in the skin lesion, and a high titer of CFG components was disclosed in the patient's peripheral blood. In this case, CFGN may have been associated with MDS; hence CFG deposits probably played a role, at least in part, in the skin lesion formation. This is probably the first case of ND complicated by CFGN. And careful examination of an underlying disease is recommended in association with ND and/or CFGN.

Cryoglobulins↗
PubMed1992

Dethymicin, a novel immunosuppressant isolated from an Amycolatopsis. Fermentation, isolation, physico-chemical properties and biological activities.

In the course of screening for immunomodulators inhibiting the mixed lymphocyte culture reaction (MLCR), we found a novel immunosuppressant, dethymicin in mycelium of Amycolatopsis mediterranei MI710-51F6. From physico-chemical properties and biological activity it is different from immunosuppressants produced by microorganisms such as cyclosporins, FK506 and rapamycin. It inhibited immune responses in vitro and in vivo, and prolonged skin allograft in rats.

Actinomycetales↗
PubMed1992

[An autopsy case of ataxic form of Creutzfeldt-Jakob disease].

An autopsy case of ataxic form of Creutzfeldt-Jakob disease (Brownell and Oppenheimer, 1965) was reported. The patient, a 71-year-old male, noticed ataxic gait at the beginning of June in 1988, and was admitted to the Hiroshima City Hospital for the neurological examination at the end of June. He showed ataxia of the left arm and legs and diplopia. Gradually he became delirious at night. On July 16, tremor-like involuntary movement of the left hand was noticed. On July 20, he became somnolent and doubly incontinent. Myoclonus and paratonic rigidity were also observed. The EEG showed periodic synchronous discharge on July 25. The brain CT and MRI were normal. He became apallic gradually and died on October 28. The duration of illness was 5 months. At autopsy, brain weighed 1000gr. Cerebral atrophy and slight enlargement of the ventricles were observed. The cerebellum was also slightly atrophic. Histologically, the destruction of the cerebral cortical layer, slight sieve-like spongy state of the neuropil, slight neuronal loss of the thalamus and sieve-like spongy state of the striatum were observed. The cerebellar lesion was the most severe, where granular cell loss and gliosis of the cortex were observed.

Aged↗
PubMed1991

Normal maximal and minimal motor nerve conduction velocities in adults determined by a collision method.

Using a new collision method, we measured motor nerve conduction velocities of the ulnar nerve in the forearm and the action potential amplitude of the abductor digiti minimi muscle on 60 adults, ages 20 to 82 years and apparently free from diseases of the peripheral nervous system. Both maximal and minimal motor nerve conduction velocities were linear functions of age; 64.42-0.05 age and 60.45-0.12 age, respectively. The percentage of the minimal to the maximal motor nerve conduction velocities was expressed as 94.45-0.13 age. The maximum amplitude of evoked muscle action potentials was also correlated with age. This novel method may be useful in detecting pathology of motor nerve fibers which results in a decrease in submaximal conduction velocities.

Action Potentials↗
PubMed1991

Maximal and minimal motor nerve conduction velocities in patients with motor neuron diseases: correlation with age of onset and duration of illness.

We measured the maximal and minimal motor nerve conduction velocities of the ulnar nerve in 17 patients with spinal muscular atrophy (SMA), 27 patients with amyotrophic lateral sclerosis (ALS), and 40 age-matched control subjects. Crude values of the maximal and minimal motor nerve conduction velocities were reduced in both patient groups, but their difference in each patient was not statistically different from that of a control subject. The conduction velocities adjusted according to each patient's age were faster in SMA patients than in ALS patients. Among patients with either ALS or SMA, the age-adjusted conduction velocities were larger in those who had developed the disease at younger ages and suffered from it for shorter periods of time. These findings suggest that the motor nerve fibers regenerate more in younger patients in the early stages of the disease, particularly in SMA.

Action Potentials↗
PubMed1991

Thermal decomposition of Lingula shell apatite.

Lingula shell is composed of apatite with a preferred orientation. The shell apatites of Lingula unguis(Lu) and Lingula shantoungensis(Ls) were characterized and compared with apatite of human tooth enamel. Insight into the Lingula apatite was studied by following the change of lattice parameter, transformation to beta-tricalcium phosphate (beta-TCP), and the loss and change of CO3, OH, and H2O after heating up to 1,000 degrees C in air and N2 for 24 hours. The OH stretching band was not observed in unheated apatites and in apatites heated in dried N2. Lu and Ls apatite produced 26 and 17 wt% of beta-TCP at 700 degrees C, respectively. Fifty to 60% of H2O was lost at 200 degrees C, being accompanied by a drastic contraction of the a- and c-axis and a drastic decrease in the crystallinity. These results indicate that (1) Lu and Ls shell apatite is CO3 containing F + Cl-apatite, and (2) the structural H2O of the Lingula apatite is loosely bounded such that they are lost at lower temperature than tooth enamel.

Animals↗
PubMed1991

Increase in susceptibility of Pseudomonas aeruginosa to carbapenem antibiotics in low-amino-acid media.

The in vitro susceptibility of Pseudomonas aeruginosa PAO1 to carbapenem antibiotics, such as CS-533, was influenced by various concentrations of basic amino acids, i.e., L-lysine, L-histidine, and L-arginine, in agar media. P. aeruginosa PAO1 showed higher susceptibility to carbapenems in minimal medium than it did in rich media such as Mueller-Hinton II agar. The susceptibility was decreased by the addition of a basic amino acid to the minimal medium, whereas it was influenced less by other amino acids. The susceptibility of PAO1 to cephalosporins, piperacillin, quinolones, and gentamicin was not influenced by the addition of a basic amino acid to the minimal medium. A significant change in susceptibility to carbapenems by the addition of a basic amino acid was not observed with D2 protein-deficient mutants of PAO1. Clinical isolates of P. aeruginosa also showed an increase in susceptibility in minimal medium. L-Lysine in minimal medium did not have any influence on the production of D2 protein, beta-lactamases, or penicillin-binding proteins of PAO1 or on the chemical degradation of CS-533. These results strongly indicate that the increase in susceptibility of P. aeruginosa to carbapenems relates to less competition with basic amino acids for permeation through the D2 protein channel of P. aeruginosa.

Agar↗
PubMed1991

[Effects on the retina and choroid of transpupillary diode laser photocoagulation].

A transpupillary retinal photocoagulator utilizing GaAlAs diode laser which emits an 810 nm beam has been constructed. It has a continuous-wave mode with a maximum output of 400 mW at the cornea. Animal experiments with monkeys were carried out successfully at various intensities to produce controlled coagulations. Observation by ophthalmoscopy, light and electron microscopes at different time intervals proved diode laser photocoagulation produced more intensive effects in choroid than krypton red laser (647 nm). However, due to the greater absorption of the choroid, there is a tendency to over-coagulation unless conditions are carefully set. No serious side effects in the retina and choroid were observed during the experiments.

Animals↗
PubMed1990

Orientation of apatite and organic matrix in Lingula unguis shell.

The orientation relationship between apatite and organic matrix in shell of Lingula unguis (inarticulate brachiopod) was studied. The organic layers, mineralized layers, and decalcified mineralized layers were examined layer by layer using microbeam X-ray diffraction technique. Both organic layer and decalcified mineralized layer showed the diffraction pattern of beta-chitin. The degree of orientation of apatite showed correlation to that of beta-chitin: Well oriented diffraction patterns of apatite crystal and organic matrix were observed in the central part. In this part, the fiber axis of beta-chitin was parallel to the c-axis of apatite. A close relationship of unit cell dimension between apatite and chitin was indicated. These strongly suggest that the fibrous structure of organic matrix assists the orientation of apatite crystals in Lingula unguis shell.

Animals↗
PubMed1990

Relative frequencies of dementia of the Alzheimer type and vascular dementia in Japanese nursing homes.

We have studied neuropathologically 200 aged nursing home residents (101 men and 99 women) autopsied between 1976 and 1985. Seventy-three of the 200 showed dementia during life, that is, 27% and 55% of the residents in nursing homes and special nursing homes, respectively. The relative frequencies of SDAT and VD in nursing homes as a whole were the same (34%). The relative frequencies of SDAT and VD in special nursing homes, where usually high concentrations of VD have been noted, were 21% and 52%, respectively. A comparison of the results of our special nursing homes (SDAT:VD = 1:2.5) and nursing homes as a whole (SDAT:VD = 1:1) with those of Barnes and Raskind (SDAT:VD = 2:1) and Rovner et al. (SDAT:VD = 3:1) showed that the frequencies of VD in Japanese nursing homes are considerably higher than those in their American counterparts.

Aged↗
PubMed1990

Effects of chelated sera and alteration in calcium concentration on the growth of oral epithelial cells in primary culture.

The purpose of this study were to examine the distribution of growth-promoting activity of some chelated sera and to investigate the relationship between calcium concentration in culture medium and the growth-promoting activity of the chelated sera in comparison with that of the original serum. Results showed that the chelated serum obtained by acidic resin treatment promoted colony formation, while the number of colonies decreased in cultures containing either dialyzed serum or chelated one obtained by treatment with alkaline resin. The acid-chelated serum and its lyophilized materials maintained the growth-promoting activity for 6 months or more in a deep freezer. This activity depended on the calcium concentration of culture medium in the range from 0.06 to approximately 1.5 mM. The optimal concentration of this material for growth promotion was 4 mg/ml as the protein density, which was about a quarter of that for the original serum protein. Sera from different sources treated with the acidic resin also showed similar effect on the growth. This finding strongly suggests that the acid-chelated serum and its lyophilized protein contain a keratinocyte growth factor(s).

Animals↗