[Mechanism of viral antigen processing and presentation].
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Biomedical subjects
Publications and source records attributed to K Kuroda.
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A novel compound, AS-183, which inhibits acyl-CoA: cholesterol acyltransferase (ACAT), was isolated from the culture broth of a fungus, Scedosporium sp. SPC-15549. AS-183 inhibited ACAT activity in an enzyme assay system using rabbit liver microsomes with an IC50 value of 0.94 microM. AS-183 also inhibited cholesterol ester formation in HepG2, CaCo2, and THP-1 cells with IC50 values of 18.1, 25.5, and 34.5 microM, respectively.
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We obtained information on patients with putaminal hemorrhage (3,638 medically treated cases and 3,372 surgically treated cases). With these data, we have developed easily applicable and clinically useful prediction models for both mortality and activities of daily living (ADL) at three months after admission. We derived these models by Hayashi's discriminant technique for categorical data. Before their derivation, variables generally available on the initial day of hospitalization and possibly related to outcome were examined individually with tests of homogeneity. Neurological grading (NG), age, deformity of cisterns around midbrain, midline shift, hematoma volume, and motor paralysis were identified as candidate predictors of both mortality and ADL. CT classification was also added to the predictors of ADL. Initially, all these factors were included in tentative models, and then those which were found not to contribute substantially to the prediction were deleted. Ultimately, we proposed two models, one for mortality and the other for ADL. The mortality model used NG, hematoma volume, and deformity of cisterns around midbrain as predictors, and the ADL model used age, NG, CT classification, hematoma volume, and motor paralysis. Average correct classification rates were 87% (medical) and 69% (surgical) for mortality, and 64% (medical) and 60% (surgical) for ADL. With these models, we evaluated indications of both kinds of treatment by comparing each predicted ADL of the medically treated cases with that of the surgically treated cases.
Double and triple helix formation of non-self complementary 2'-5' and 3'-5' linked oligonucleotides, 3'-5'(pA)7, 3'-5'(pU)7, 2'-5'(pA)7 and 2'-5'(pU)7, was studied using UV and CD spectroscopies. UV mixing curve and UV melting curve showed that 3'-5'(pA)7:3'-5' (pU)7 system could form double and triple helix, while 2'-5'(pA)7:2'-5'(pU)7 system could form only double helix and 3'-5'(pA)7:2'-5'(pU)7 system could form neither double nor triple helix under the condition examined. Thermodynamic parameters obtained from the UV melting curve indicate that the linkage type of oligonucleotides has profound effect on the helix formation.
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The injection of B16F10 melanoma cells with recombinant human tumor necrosis factor alpha (TNF-alpha) into the tail vein of C57BL/6 mice resulted in 2- to 25-fold more metastatic foci in the lungs than the injection of tumor cells alone. Clearly, TNF-alpha significantly enhanced experimental tumor metastasis. Furthermore, it enhanced the metastasis of Lewis lung carcinoma cells. In contrast, a mutein of TNF-alpha, designated as F4236, having the cell-adhesive sequence (Tyr-Ile-Gly-Ser-Arg) at the N-terminus of the TNF molecule did not enhance metastasis, but rather exhibited similar antitumor activity to wild-type TNF-alpha in fibrosarcoma-bearing mice.
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Genotoxicity of 10 pesticides (chlornitrofen, chlomethoxyfen, molinate, thiobencarb, simazine, simetryn, diazinon, iprofenfos, piperofos and oxadiazone) was studied by mitotic toxicity, sister chromatid exchange, and rec assay. The pesticides are detected frequently at high levels in the Yodo River water in Osaka, Japan, which is used for drinking water by thirteen million people. Mitotic toxicity was evaluated by mitotic index (MI) and second mitosis index (SI), using a Chinese hamster cell line V79. SI is the rate of twice divided metaphases in chromosome preparation for sister chromatid exchange. All the pesticides decreased the two indices dose-dependently. MI50 and SI50, the concentrations of pesticides which lowered the indices to 50% of the solvent control, was determined. The MI50 and SI50 of each pesticide were very similar, and the pesticides did not hinder cell division specifically. None of the pesticides induced more sister chromatid exchanges than 1.5 times the solvent control. Chlomethoxyfen and simazine induced sister chromatid exchanges significantly in V79 cells, but the dose dependencies were poor. Simetryn had rec effect and was concluded to have DNA damaging activity.
An enzyme-linked immunosorbent assay method for serodiagnosis of cancers was developed by employing histone H2B. This method measures anti-histone H2B antibody levels in sera and includes a device for coating the plastic immunoplate with a mixture of histone H2B and diluted fetal calf serum. The coating of immunoplates with this mixture decreased apparent sensitivity of the assay compared with that in the absence of fetal calf serum, but effective reduction of nonspecific background enabled a specific assay of anti-histone H2B antibody with excellent reproducibility. By this method cancer patients were discriminated from normal healthy subjects at detection rates of 37% for lung cancer, 33% for liver cancer, 50% for pancreatic cancer, 42% for colon cancer, and 78% for cervical cancer. However, stomach and esophagus cancers showed detection rates of less than 17%, which are comparable to the values for benign diseases. It is likely that this assay method detects squamous cell carcinomas at relatively high rates.
Some commercial liquid smoke flavourings have been shown to induce acute gastric mucosal injury in rats when given orally as a large single dose. The present study was carried out to examine the mechanism of action in rats of two selected smoke flavourings containing about 10% total acids as acetic acid. These flavourings and 10% acetic acid decreased the concentration of glutathione (GSH) in the glandular stomach. The decrease in gastric GSH was coupled with smoke flavouring-induced gastric injury. Pretreatment with N-ethylmaleimide, a GSH depletor, enhanced acetic acid-induced gastric injury. Pretreatment with cysteine, a sulphhydryl compound, protected rats against smoke flavouring-induced gastric injury. Aqueous fractions of the smoke flavourings, after removal of non-polar compounds and acidic organic compounds (including acetic acid) by diethyl ether extraction, decreased the gastric GSH concentration considerably and had a marked reactivity in vitro with GSH, but these fractions by themselves showed no ability to induce gastric injury. Addition of 10% acetic acid to these aqueous fractions caused greater gastric injury than 10% acetic acid alone, which suggests that these aqueous fractions contain the (unidentified) compound(s) that facilitate acetic acid-induced gastric injury. These findings indicate that gastric endogenous and exogenous sulphhydryls play an important part in gastric cytoprotection.
We studied the outcome in 308 patients with acute myocardial infarction (MI) admitted to the coronary care unit of Kobe General Hospital. Short-term outcome (within 28 days after MI) and long-term outcome (more than 28 days) were examined with survival curves to find any relationship with a history of previous MI and with the site of the MI. In the short term, 38 of the 308 patients died of cardiac causes. The group with anterior MI tended to have higher mortality than the group of patients with inferior MI, and among patients without a previous MI, patients with anterior MI had significantly higher mortality (p = 0.01). In multivariate analysis by the logistic regression model, the site of the MI was found to be independently associated with the short-term outcome. In the long term, with a mean follow-up of 3.4 years, 23 of the 308 patients died of cardiac causes. Different sites of the MI did not result in different outcomes in patients with or without a previous MI. Of patients with anterior or inferior MI, those with a previous MI tended to have higher mortality, and of patients with an inferior MI, the difference was significant (p = 0.001). In multivariate analysis by the proportional hazards model, a history of MI was more predictive than the site of the MI. In conclusion, the site of the MI was associated more with the short-term outcome than with the long-term outcome, and a history of MI was associated more closely with the long-term outcome.
The characteristics and social backgrounds of 61 elderly patients with long hospital stays and those of 179 incapacitated elderly people living at home in a Japanese city were compared. Discriminant function analysis was performed to clarify the factors associated with long-term use of hospital beds by elderly people. In addition to this analysis, the elderly patients with long hospital stays were divided into two subgroups according to the likelihood of discharge, and these subgroups were compared in the same way. The elderly patients with long hospital stays were more likely to be women, persons with low ADL, living alone and not living with a spouse or a second generation, compared with incapacitated elderly people living at home. Analysis of the subgroups of the elderly subjects with long hospital stays showed that use of a urethral catheter and not undergoing rehabilitation were the medical factors related to difficulty of discharge, while being women, of advanced age and not having their own room at home were the non-medical factors associated with long-term occupation of hospital beds.
Resonance Raman (RR) spectra of the complex of pig kidney medium-chain acyl-CoA dehydrogenase with acetoacetyl-CoA and of the purple complex formed upon the addition of octanoyl-CoA to the dehydrogenase were obtained. RR spectra were also measured for the complexes prepared by using isotopically labeled compounds, i.e., [3-13C]-, [1,3-13C]-, and [2,4-13C2]acetoacetyl-CoA; [1-13C]octanoyl-CoA; the dehydrogenase reconstituted with [4a-13C]- and [4,10a-13C2]FAD. Both bands of oxidized flavin and acetoacetyl-CoA were resonance-enhanced in the 632.8 nm excited spectra of the acetoacetyl-CoA complex; this confirms that the broad long-wavelength absorption band is a charge-transfer absorption band between oxidized flavin and acetoacetyl-CoA. The 1,622 cm-1 band was assigned to the C(3)=O stretching mode coupling with the C(2)-H bending mode of the enolate form of acetoacetyl-CoA and the bands at 1,483 and 1,119 cm-1 were assigned to bands associated with the C(2)=C(1)-O- moiety. Both bands of fully reduced flavin and the substrate were resonance-enhanced in the 632.8 nm excited spectra of the purple complex. As the enzyme is already reduced, the substrate must be oxidized to octenoyl-CoA; the complex is a charge-transfer complex between the reduced enzyme and octenoyl-CoA. The low frequency value of the 1,577 cm-1 band, which is associated with the C(2)-C(1)=O moiety of the octenoyl-CoA, suggests that the enzyme-bound octenoyl-CoA has an appreciable contribution of C(2)=C(1)-O-.(ABSTRACT TRUNCATED AT 250 WORDS)
In the present study we have investigated the role of the hydrophobic domains of the fowl plague virus (FPV) haemagglutinin (HA) on its intracellular transport and maturation in insect cells. To this end processing of full-length HA (A+) has been compared to that of two truncated forms lacking either the cytoplasmic domain and the transmembrane domain (A-) or lacking the entire HA2 subunit, i.e. the transmembrane domain and the fusion peptide (HA2-). All glycosylation sites present on A- and HA2- were glycosylated, indicating that both truncated forms were completely translocated in the endoplasmic reticulum. Unlike A+, A- and HA2- did not form trimers as indicated by cross-linking, gradient centrifugation and studies employing conformation-specific antibodies. Whereas HA2- was efficiently secreted, A- was retained in the cells in an apparently membrane-bound form. The data show that the carboxy-terminal transmembrane region is essential for the formation and stability of the trimers of the FPV HA. These observations also indicate that, under certain conditions, the fusion peptide of the FPV HA can serve as a membrane anchor.