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T Mita

Publications and source records attributed to T Mita.

At least 37 records · Page 2Linked to original sources
PubMed1998

Interaction of amphotericin B with cholesterol in monolayers, aqueous solutions, and phospholipid bilayers.

The interaction of amphotericin B (AmB) with cholesterol was investigated in monolayers, aqueous solutions, and phospholipid vesicles. When AmB was mixed with cholesterol, it formed a stable monolayer, implying complex formation in which the stoichiometry was primarily 1:1 AmB:cholesterol. However, the interaction of AmB with cholesterol in aqueous solutions and lipid vesicles was more complex. In aqueous solutions, cholesterol at low concentrations increased the aggregation of AmB. But higher concentrations of cholesterol caused dissociation of the aggregates of AmB due to the formation of AmB-cholesterol complexes. In lipid vesicles, the effect of cholesterol was different from that in aqueous solutions. Both in aqueous solutions and lipid vesicles, the overall dissociation of AmB molecules occurred on interaction with cholesterol. In addition, the interaction of lipid membranes with AmB-cholesterol complexes was investigated by differential scanning calorimetry. The incorporation of AmB into lipid bilayers led to broadening of the lipid transition and a slight decrease in the transition enthalpy, showing that one lipid molecule per AmB molecule was immobilized. However, the number of immobilized lipid molecule per AmB molecule increased in the coexistence of cholesterol, due to the complex formation between AmB and cholesterol.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1998

A case of subwakefulness syndrome.

We report a patient, a 30-year-old male Japanese-Brazilian migrant construction worker, suffering from excessive daytime sleepiness for at least 6 months. Electroencephalogram recordings during his waking states showed that 10-Hz and 60-microV alpha activity was present prominently in the occipital regions. From the multiple sleep latency test, it was found that stages 1-2 NREM sleep episodes appeared repetitively without any REM episodes, and that the mean sleep latency was 10.2 min. These findings support the diagnosis that this patient suffers from subwakefulness syndrome.

Adult↗
PubMed1998

Bilirubin binding activity of cytokeratin 18 isolated from the porcine liver.

A porcine liver 40 kDa protein designated SBP40 isolated by affinity chromatography with agarose-linked spermine was identified as a porcine cytokeratin 18 on the basis of partial amino acid sequences of peptides derived by lysylendopeptidase digestion and by its reactivity with two commercially available preparations of monoclonal antibody. Immunohistochemistry revealed that SBP40 is localized at the hepatocyte membranes, preferentially in the bile canalicular area in accordance with the previously reported localization of cytokertain 18 in the murine liver. Affinity chromatography with agarose-linked bilirubin, a solubilization experiment of bilirubin from bilirubin-Sephadex G-10 complex, and gel-filtration of a mixture with bilirubin demonstrated that SBP40 or porcine cytokeratin 18 has binding affinity for bilirubin. These results suggest that cytokeratin 18 may play a role as a membrane reservoir in the event of transport and secretion of bile pigments in the liver.

Amino Acids↗
PubMed1997

Granule cell disinhibition in dentate gyrus of genetically seizure susceptible El mice.

Paired-pulse inhibition was investigated electrophysiologically in the dentate gyrus using hippocampal slices from epileptic El mice. At short interpulse intervals (IPIs), the inhibition was 30% in the El, and 90% in the control ddY mice at the ages of 10 and 15 weeks. No difference in inhibition was observed at the age of 5 weeks. Bicuculline, a GABAA receptor antagonists, attenuated the inhibition during short IPIs n the ddY mice, while in the El mice, phenobarbital and flunitrazepam, which enhance GABAA receptor function, restored the inhibitory activity comparable to that of the ddY. The disinhibition progressed with growth, closely correlating with seizure development in El mice. These results suggest that decrease in the GABAergic inhibition occurs in the dentate gyrus of the El mice with growth. GABA concentration in the hippocampus was also quantified using HPLC. In El mice, GABA level was significantly lower than that in ddY mice at the ages of 5 and 15 weeks. Thus, the disinhibition observed in the El dentate gyrus at 15 weeks of age does not appear to be directly related to the content of GABA. GABAergic disinhibition suggests possible loss of unknown inhibition control factor(s) in the El dentate gyrus as growth progresses. The growth-dependent disinhibition in the granule cells may be prerequisite for epileptogenesis in El mice.

Aging↗
PubMed1997

Inhibition of collagenases from mouse lung carcinoma cells by green tea catechins and black tea theaflavins.

Theaflavin and theaflavin digallate, which are components of black tea were examined by in vitro invasion assay with mouse Lewis lung carcinoma LL2-Lu3 cells, which are highly metastatic. The compounds inhibited invasion by the tumor cells. Gelatin zymography showed that the cells secreted matrix metalloproteinases (MMPs), probably including MMP-2 and MMP-9, which may be involved in tumor cell invasion and metastasis. Theaflavin and theaflavin digallate also inhibited MMPs from the culture medium of these tumor cells, as did (-)-epigallocatechin gallate. These results suggest that theaflavin, theaflavin digallate, and (-)-epigallocatechin gallate inhibit tumor cell invasion by inhibiting type IV collagenases of the LL2-Lu3 cells.

Animals↗
PubMed1997

[A case of retinochoroidal optic neuropathy].

The patient was a 59-year-old male with impaired left vision. Before he was referred to this hospital, he was diagnosed as having optic nerve injury due to the trauma of a severe bruise on his left eye caused by a traffic accident, and relative afferent pupillary defect (RAPD) was negative. On his first examination in this department, RAPD was negative and funduscopy of the left eye demonstrated hyperemia of the optic disc and mild opacification at the posterior pole. Fluorescein fundus angiography showed circular hyperfluorescence around the optic disc and transverse linear hyperfluorescence appearing above and below the macula. From these findings a diagnosis of choloidal rupture was made. The form of choloidal rupture suggested an early stage of evulsion of the optic nerve. The impairment of visual acuity seemed to be caused by choloidal circulatory disturbance. The patient was therefore, had traumatic retinocholoidal optic neuropathy complicated by the rupture of the choloidal around the optic disc, disturbance of the optic disc, and opacification of the retinochoroid.

Accidents, Traffic↗
PubMed1996

Down-regulation of S-adenosylhomocysteine hydrolase in the active methyl transfer system in the brain of genetically epileptic El mice.

To study the role of cerebral methylation in epileptogenesis, we investigated the active methyl transfer pathway in the brain of genetically epileptic El mice. We examined S-adenosylhomocysteine (AdoHcy) hydrolase activity (by high performance liquid chromatography), the corresponding mRNA levels (by competitive reverse transcription-polymerase chain reaction), as well as S-adenosylmethionine (AdoMet) and AdoHcy levels in epileptic El and non-epileptic control ddY mice. The level of AdoHcy, a potent feedback inhibitor in the methyl transfer system, was relatively high throughout growth, particularly in 15 week old El mice where it was increased approximately 20% compared to control ddY mice. AdoHcy hydrolase activity in the El mice brain did not increase during growth, which was confirmed by the finding that mRNA synthesis from the hydrolase gene behaved likewise. In contrast, ddY mice exhibited a gradual increase in the mRNA synthesis up to three fold and 20% increase in the enzyme activity at 15 weeks of age compared to those of El mice in which the seizure frequency was 100%. The levels of AdoMet, a versatile methyl donor, did not change throughout growth. We concluded that the down-regulation of AdoHcy hydrolase results in the accumulation of AdoHcy, possibly inducing an unstable state including seizures in the El mouse brain. El mice predisposed to epilepsy may be characterized by disordered feedback regulation of the AdoMet-dependent methyl transfer pathway.

Adenosylhomocysteinase↗
PubMed1996

Presence of atypical laminin on the surface of mouse Lewis lung carcinoma cells.

We investigated the expression and distribution of laminin in Lewis lung carcinoma LL2-Lu3 cells. The microscopic immunofluorescence study of the non-permeabilized cells and blotting assay after immunoprecipitation with anti-laminin antibodies of biotinylated cell surface proteins demonstrated that LL2-Lu3 cells retained laminin on their cell surfaces. This laminin was atypical in that it lacked A chain as revealed by the immunoblot analysis. The results of the reverse transcription polymerase chain reaction method indicated that LL2-Lu3 cells contained mRNA for B1 and B2 chains, but not A chain corresponding to those of typical laminin derived from murine Engelbreth-Holm-Swarm sarcoma. A precursor form of 67 kDa laminin receptor protein was also shown to exist on the surfaces of LL2-Lu3 cells. These findings suggest that the interaction between atypical laminin and the precursor form of the 67 kDa laminin receptor protein on the cell surfaces may function in regulating cell activities such as metastasis of LL2-Lu3 cells.

Animals↗
PubMed1995

Analysis of cis-acting regions upstream of the rat Na+/K(+)-ATPase alpha 1 subunit gene by in vivo footprinting.

By means of in vivo footprinting, we examined the putative cis-acting DNA elements located between -50 and -122 of rat Na+/K(+)-ATPase alpha 1 subunit gene ATP1A1. Proximal and distal GC box sequences and a consensus sequence for the active transcription factor (ATF) were protected for all the tissues examined (kidney, brain and liver). Putative cooperation between two binding factors on the ATF site and the proximal GC box was observed. The overall in vivo footprinting profiles of the three tissues did not exhibit any marked differences that could account for the variation in the extent of tissue-specific transcription. The alpha 1 regulatory element (ARE) found by Suzuki-Yagawa et al. does not appear to be an element responsible for tissue-specific regulation of the gene.

Animals↗
PubMed1995

Isolation and mapping of 186 new DNA markers on human chromosome 1.

To obtain DNA markers on human chromosome 1, we first isolated 500 cosmid clones from mouse A9 cells containing a human chromosome 1 tagged with pSV2neo. Of these, 186 were localized on each band of human chromosome 1 by R-banding fluorescence in situ hybridization; 118 and 68 were on the short and long arms, respectively. We performed restriction fragment length polymorphism (RFLP) analysis of these cosmid clones, and polymorphism was recognized with one or more enzyme in 43 of them. Two markers proved to have variable numbers of tandem repeats. Since several tumor suppressor genes, as well as genes responsible for hereditary disorders, may be located on this human chromosome, the DNA markers will be useful for RFLP analysis or the isolation of new genes related to various disorders.

Chromosome Mapping↗
PubMed1995

Isolation of a novel collagen-binding protein from the mushroom, Hypsizigus marmoreus, which inhibits the Lewis lung carcinoma cell adhesion to type IV collagen.

A type IV collagen-binding protein of 23 kDa was isolated from the mushroom, Hypsizigus marmoreus. This protein, HM 23, bound to type IV and type I collagens and gelatin, and to much lesser extent to fibronectin, but not to laminin or bovine serum albumin. The adhesion of Lewis lung carcinoma cells was inhibited when the type IV collagen substratum was pretreated with HM 23. A computer search of the determined partial amino acid sequence indicated no homologous proteins reported. These results indicate that HM 23 is a hitherto undescribed fungus protein that can interact with animal extracellular matrix proteins.

Amino Acid Sequence↗
PubMed1995

Cytokinesis by a contractile ring in the primitive red alga Cyanidium caldarium RK-1.

To better understand the mechanism of cytokinesis in eukaryotes, the behavior of the contractile ring in the two unicellular primitive red algae Cyanidioschyzon merolae and Cyanidium caldarium RK-1, which have the smallest genome size among eukaryotes, was examined by fluorescein isothiocyanate (FITC)-phalloidin fluorescence microscopy, fluorometry using a video-intensified microscope photoncounting system, transmission electron microscopy and immunoblotting techniques. Cells in each alga contained one nucleus, one mitochondrion and one chloroplast, which were aligned in that order. During cytokinesis in C. merolae, a contractile ring was not observed by fluorescence microscopy or by transmission electron microscopy. In contrast, in C. caldarium RK-1, a contractile ring appeared at the equatorial region of the dividing cells and began to contract from the side of the chloroplast. During contraction of this ring, the total fluorescent intensities due to FITC-phalloidin remained constant. Electron microscopy revealed outer and inner bands approximately 80 nm wide and 9 nm thick which ran parallel to each other just beneath the cell membrane. These bands were visible at the equator of the cell just before the initiation of cytokinesis and constricted from the pole of the chloroplast. Both bands increased in width as cleavage progressed. The inner ring consisted of a bundle of approximately 20 actin-like filaments which were arranged as a raft. In the outer ring, such fine filaments were not visible. It seems likely that the bundle of filaments, known as the contractile ring, is composed of two different elements: an inner band of actin filaments and an outer band of unknown materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1995

[An attempt to prevent psychological distress induced by magnetic resonance imaging: effectiveness of psychological interventions].

A magnetic resonance imaging (MRI) examination has reportedly produced psychological distress such as discomfort, anxiety and fear in a certain number of patients. In an attempt to prevent such distress during an MRI, the authors took the following psychological measures: 1) improved psychological support for patients by MRI technicians; 2) providing sufficient information to patients about the imager and the nature of the examination; 3) reassurance of the safety, with the patient free to terminate the examination at any time; 4) environmental modification to induce relaxation, including recorded music, paintings and live plants in the examination room. We then evaluated the effectiveness of these combined psychological support factors for all MRI patients. A questionnaire on psychological distress experienced during an MRI was filled out by 143 patients (mean age, 49.4 years) and 105 patients (mean age, 48.4 years) prior to and after our psychological measures, respectively, after MRI test in Saiseikai Nakatsu hospital, and comparisons made between these two groups (chi 2 test, p < 0.05). The number of patients experiencing psychological distress during an MRI was significantly decreased (50.5%) after the measures were implemented as compared to the number (64.3%) beforehand. In particular, female, 60 or older patients and patients examined for the first time showed significant decreases in experiencing psychological distress after the measures were implemented. The number of patients who reported distress, tended to decrease. Patients who developed certain symptoms, such as palpitation, also tended to decrease. Patients who reported the "long examination time" as a distress factor and those who developed palpitation during the examination significantly decreased. Our results indicate that these combined psychological measures are efficacious in reducing psychological distress during an MRI, mainly by curtailing the patient's subjective sense of examination time. In addition to an MRI examination, our psychological measures should be applied to other medical examinations which tend to generate undue psychological distress.

Adolescent↗
PubMed1995

[Clinical implications of mismatched uptakes of beta-methyl fatty acid analogue and thallium in infarcted myocardium: correlations with coronary stenosis and regional wall motion abnormality].

Myocardial perfusion and fatty acid metabolism were assessed by using myocardial single-photon emission computed tomography with thallium and beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) during acute and/or late stages of myocardial infarction in 157 infarcted segments of 100 patients. The incidence of reduced thallium perfusion relative to BMIPP uptake ("T-type" mismatch) was significantly (p < 0.05) lower (9%) compared to that of reduced BMIPP uptake relative to thallium perfusion ("B-type" mismatch) (59%) or non-mismatched segment (32%). In an anteroseptal region, B-type dissociation had a significantly higher incidence compared to no or T-type mismatch; 68% vs. 27% vs. 5%, respectively, whereas the incidence of T-type uptake was relatively high in inferior and posterolateral regions; 13%, 11%, respectively. Severe coronary stenosis was observed in 76% of B-type segments and 72% of non-mismatched segments but in only 43% of T-type segments. The incidence of regional wall motion abnormality was significantly lower (46%) in the T-type mismatch segments when compared to the B-type (91%) or non-mismatched segments (96%). In conclusion, myocardial fatty acid metabolism was more markedly impaired compared to an involved coronary perfusion, resulting in the mismatch of perfusion and fatty acid metabolism. Coronary stenosis and regional wall motion abnormality are more closely related to "B-type" mismatch but not necessarily to "T-type" dissociation, probably because of attenuation artifacts in inferior and posterolateral regions in thallium scan.

Aged↗
PubMed1994

[Blood flow pattern in pulmonary atelectasis with color Doppler flow imaging].

Blood flow pattern in the lesion was evaluated in 4 patients with pulmonary atelectasis by color Doppler flow imaging synchronized electrocardiography. The pulsatile signal and triphasic signal were detected, whereas the continuous signal was not. It seemed that in pulmonary atelectasis the pulsatile signal was the blood flow signal in the pulmonary artery and the triphasic signal was the blood flow signal in the pulmonary vein.

Aged↗