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Biomedical subjects

M Yamazaki

Publications and source records attributed to M Yamazaki.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Clinical evaluation of an immunochromatography test for rapid diagnosis of influenza].

We evaluated a rapid diagnostic kit that detects influenza type A and B viral antigens by immunochromatography, Quick Vue Influenza Test (Quidel Corp., San Diego, CA, USA), with 425 specimens collected from patients with influenza-like symptoms at three hospitals between January and March 2001. The specimens included 184 nasal aspirates, 140 nasal swabs, and 101 throat swabs. The test correctly identified 179 of the 204 culture positive specimens and 203 of the 221 culture negative specimens; the sensitivity and specificity compared with the culture were 87.7% and 91.9%, respectively. The sensitivity of the test was 92.6% (112/121) for nasal aspirates, 83.7% (41/49) for nasal swabs, and 76.5% (26/34) for throat swabs, which is similar to the results for conventional rapid enzyme immunoassay kits for influenza virus infection. The sensitivity and specificity of the QuickVue Influenza Test were equivalent to those of Flu OIA (BioStar, Inc., Boulder, CO, USA), with the agreement of 84.2%. Although the QuickVue Influenza Test does not differentiate between influenza A and B viruses, the easy-to-use kit detects both types in the physician's office, allowing physicians to make a decision on prescription of neuraminidase inhibitor therapy during the initial visit.

Evaluation Studies as Topic↗
PubMed2001

Amino acid substitution analyses of the DNA contact region, two amphipathic alpha-helices and a recognition-helix-like helix outside the dimeric beta-barrel of Epstein-Barr virus nuclear antigen 1.

OBJECTIVES AND METHODS: Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1), which is essential for EBV latency, homodimerizes and binds to the EBV replication origin, oriP. We analyzed the dimerization/DNA-binding domain of EBNA-1 by random and site-directed amino acid substitution. RESULTS: Random point mutations that resulted in reduced DNA binding clustered in the DNA contact region (a.a. 461-473) and at or near the termini of alpha-helix II (514-527). Three substitutions of Gly in the DNA contact region each greatly reduced binding to a single binding site oligonucleotide. Substitutions at and near the termini of alpha-helix II diminished DNA binding. A helix-deforming substitution in alpha-helix I (477-489) blocked DNA binding. A helix-deforming substitution in alpha-helix III (568-582) abolished dimerization and DNA binding. Similarities in surface electrostatic properties and conserved amino acids were found between alpha-helix II and recognition helices of papillomavirus E2 proteins. CONCLUSIONS: The basic DNA contact region is crucial for the specific interaction of EBNA-1 with a single binding site. Alpha-helix I477 is indispensable for oriP binding, and alpha-helix III568 contributes to the homodimeric structure of EBNA-1. Alpha-helix II514 contributes to oriP binding, perhaps changing its alignment with DNA.

Amino Acid Sequence↗
PubMed2001

Effect of polyacetylenes on the neurite outgrowth of neuronal culture cells and scopolamine-induced memory impairment in mice.

Polyacetylenic alcohols and their linoleates isolated from Panax ginseng C. A. MEYER and Cirsium japonicum DC., of which the lipophilic extracts had been found to affect the neuritogenesis of cultured paraneurons, were demonstrated to have a significant neuritogenic effect on PC12h and Neuro2a cells. Panaxynol and the acetylenic triol in particular were highly efficient at concentrations > or = 2 microm. Panaxynol (20 mg/kg/d, i.p., for 3 d) was confirmed to improve scopolamine-induced memory deficit in mice (Y-maze task). It is suggested that the promotion of neuritogenesis in cultured paraneurons by the addition of panaxynol is related its ability to improve memory deficits in animals.

Acetylene↗
PubMed2001

Prevention of the neurotoxicity of the amyloid beta protein by genipin.

Genipin, which was shown in our previous investigation to have prominent neuritogenic activity in paraneurons such as PC12h cells, was studied to determine whether it could prevent the toxicity of Alzheimer's amyloid beta protein (Abeta) in cultured hippocampal neurons. Increased release of lactate dehydrogenase from hippocampal neurons after 2 d of Abeta25-35 administration was prevented dose dependently by the addition of genipin 20-40 microm. Morphological observations and trypan blue staining of cells confirmed the protection of hippocampal neurons from Abeta toxicity by genipin. Geniposide had less effect in preventing Abeta toxicity.

Amyloid beta-Peptides↗
PubMed2001

Anti-androgenic activity of Myricae Cortex--isolation of active constituents from bark of Myrica rubra.

The aqueous ethanol extract of Myricae Cortex (bark of Myrica rubra Sieb. et Zucc., Myricaceae) showed in vitro testosterone 5alpha-reductase inhibitory activity and in vivo anti-androgenic activity using growth of flank organ in castrated Syrian hamsters and/or hair regrowth after shaving in testosterone-treated C57Black/6CrSlc mice. Three constituents, myricanone, myricanol, and myricetin were identified as the main active principles.

5-alpha Reductase Inhibitors↗
PubMed2001

Testosterone 5alpha-reductase inhibitory active constituents from Anemarrhenae Rhizoma.

The diethyl ether extract of Anemarrhenae Rhizoma (rhizomes of Anemarrhena asphodeloides Bunge) showed testosterone 5alpha-reductase inhibitory activity. Two major constituents, cis-hinokiresinol (1) and 2,6,4'-trihydroxy-4-methoxybenzophenone (2) were identified as the active principles. The inhibitory activity of 1 was superior to that of ethinylestradiol, but that of 2 was weak.

5-alpha Reductase Inhibitors↗
PubMed2001

Racemization kinetics of meluadrine tartrate in aqueous solution.

The kinetics of racemization of meluadrine tartrate in aqueous solution was investigated by HPLC, over the pH range of 1.2 to 12 at 40, 60 and 80 degrees C. The racemization was followed by measuring both the residual (R)-enantiomer and formed (S)-enantiomer of meluadrine. The pH-racemization rate profile of meluadrine showed a minimum racemization rate constant between pH 4 and 6, and the rate constant increased rapidly with decreasing pH below pH 3. In the basic region, the racemization rate constant showed a maximum at around pH 9. Four pathways of racemization of meluadrine are proposed, depending on the dissociation state of the phenolic and amino groups. The calculated racemization rate-pH profile agreed well with the observations. The values of activation energy (95-115 kJ/mol) suggest that a similar quinoid intermediate is involved throughout the pH range examined. The objective of this study is to clarify the racemization mechanism of benzylalcohol derivative with phenoric group. This study offers fundamental knowledge for the other benzylalcohol derivatives, which have similar moiety structure.

Adrenergic beta-2 Receptor Agonists↗
PubMed2001

Analgesic components of saposhnikovia root (Saposhnikovia divaricata).

By activity-oriented separation using the writhing method in mice, the analgesic components of Saposhnikovia root (Saposhnikovia divaricata Schischkin; Umbelliferae) were identified to be chromones, coumarins, polyacetylenes and 1-acylglycerols. Two new components, divaricatol and (3'S)-hydroxydeltoin, were also isolated. The most potent analgesia was observed in chromones such as divaricatol, ledebouriellol and hamaudol, which inhibited writhing inhibition at an oral dose of 1 mg/kg in mice. Acylglycerols also showed inhibition significantly at a dose of 5 mg/kg. In some pharmacological tests using sec-O-glucosylhamaudol, the compound showed analgesia by the tail pressure and the Randall & Selitto methods, and its writhing inhibition was not reversed by naloxone.

Analgesics, Non-Narcotic↗
PubMed2001

[Inhibition effect of Amaryllidaceae alkaloids, lycorine and lycoricidinol on macrophage TNF-alpha production].

We previously demonstrated that Amaryllidaceae alkaloids, lycorine and lycoricidinol, inhibit induction of apoptosis by calprotectin derived from neutrophils, and that the latter alkaloid showed suppression in rat adjuvant-induced arthritis model. These findings suggest that the alkaloids have a modulating activity against inflammatory reaction. To explore further the mechanism of the suppression for inflammation, we studied the effect of the alkaloids on macrophage tumor necrosis factor (TNF-alpha) production in vitro, since TNF-alpha is recognized as a pivotal cytokine to regulate inflammation. As a result of this study, lycorine and lycoricidinol inhibited TNF-alpha production of murine macrophages stimulated with lipopolysaccharide (ID50 were 0.2 microgram/ml and 0.002 microgram/ml, respectively). The inhibition was also observed in macrophages treated by Gram-positive bacteria, Enterococcus faecalis. Both lycorine and lycoricidinol reportedly have inhibitory activity for protein biosynthesis. Although the inhibition of TNF-alpha production by lycoricidinol was mainly due to the inhibition of protein biosynthesis, lycorine showed inhibition against TNF-alpha production at lower concentrations than the case that they inhibited 35S-Cysteine/35S-Methionine incorporation into macrophages. These facts suggest that the inhibition of TNF-alpha production is not due to the inhibitory activity against protein translation at least at lower concentrations. From these results, it was concluded that these alkaloids exert inhibitory effects not only on neutrophil apoptosis-inducing protein, calprotectin, but also on macrophage TNF-alpha production.

Alkaloids↗
PubMed2001

Anti-inflammatory and anti-allergic actions by oral administration of a perilla leaf extract in mice.

The anti-inflammatory and anti-allergic activity of perilla leaf extract was investigated. The oral administration of perilla leaf extract to mice inhibited two types of acute inflammatory models, arachidonic acid-induced ear edema and 12-o-tetradecanoylphorbol-13-acetate-induced ear edema. Oral administration of perilla leaf extract also inhibited the contact dermatitis model, oxazolone-induced ear edema, by affecting sensitization.

Administration, Oral↗
PubMed2001

Spatial and temporal collagen gene expression in lumbar intertransverse fusion in the rabbit.

We have examined the process of fusion of the intertransverse processes and bone graft in the rabbit by in situ hybridisation and evaluated the spatial and temporal expression of genes encoding pro-alpha1 (I) collagen (COL1A1), pro-alpha1 (II) collagen (COL2A1) and pro-alphal (X) collagen (COL10A1). Beginning at two weeks after operation, osteogenesis and chondrogenesis occurred around the transverse process and the grafted bone at the central portion of the area of the fusion mass. Osteoblasts and osteocytes at the newly-formed woven bone expressed COL1A1. At the cartilage, most chondrocytes expressed COL2A1 and some hypertrophic chondrocytes COL10A1. In some regions, co-expression of COL1A1 and COL2A1 was observed. At four weeks, such expressions for COLlA1, COL2A1 and COL10A1 became prominent at the area of the fusion mass. From four to six weeks, bone remodelling progressed from the area of the transverse processes towards the central zone. Osteoblasts lining the trabeculae expressed a strong signal for COL1A1. At the central portion of the area of the fusion mass, endochondral ossification progressed and chondrocytes expressed COL2A1 and COL10A1. Our findings show that the fusion process begins with the synthesis of collagens around the transverse processes and around the grafted bone independently. Various spatial and temporal osteogenic and chondrogenic responses, including intramembranous, endochondral and transchondroid bone formation, progress after bone grafting at the intertransverse processes. Bone formation through cartilage may play an important role in posterolateral spinal fusion.

Animals↗
PubMed2001

Expression of osteoprotegerin, receptor activator of NF-kappaB ligand (osteoprotegerin ligand) and related proinflammatory cytokines during fracture healing.

Fracture healing is a unique biological process regulated by a complex array of signaling molecules and proinflammatory cytokines. Recent evidence for the role of tumor necrosis family members in the coupling of cellular functions during skeletal homeostasis suggests that they also may be involved in the regulation of skeletal repair. The expression of a number of cytokines and receptors that are of functional importance to bone remodeling (osteoprotegerin [OPG], macrophage colony-stimulating factor [M-CSF], and osteoprotegerin ligand [receptor activator of NF-kappaB ligand (RANKL)]), as well as inflammation (tumor necrosis factor alpha [TNF-alpha] and its receptors, and interleukin-1alpha [IL-1alpha] and -beta and their receptors) were analyzed over a 28-day period after the generation of simple transverse fractures in mouse tibias. OPG was expressed constitutively in unfractured bones and elevated levels of expression were detected throughout the repair process. It showed two distinct peaks of expression: the first occurring within 24 h after fracture and the second at the time of peak cartilage formation on day 7. In contrast, the expression of RANKL was nearly undetectable in unfractured bones but strongly induced throughout the period of fracture healing. The peak in expression of RANKL did not correlate with that of OPG, because maximal levels of expression were seen on day 3 and day 14, when OPG levels were decreasing. M-CSF expression followed the temporal profile of RANKL but was expressed at relatively high basal levels in unfractured bones. TNF-alpha, lymphotoxin-beta (LT-beta), IL-1alpha, and IL-1beta showed peaks in expression within the first 24 h after fracture, depressed levels during the period of cartilage formation, and increased levels of expression on day 21 and day 28 when bone remodeling was initiated. Both TNF-alpha receptors (p55 and p75) and the IL-1RII receptor showed identical patterns of expression to their ligands, while the IL-1R1 was expressed only during the initial period of inflammation on day 1 and day 3 postfracture. Both TNF-alpha and IL-1alpha expression were localized primarily in macrophages and inflammatory cells during the early periods of inflammation and seen in mesenchymal and osteoblastic cells later during healing. TNF-alpha expression also was detected at very high levels in hypertrophic chondrocytes. These data imply that the expression profiles for OPG, RANKL, and M-CSF are tightly coupled during fracture healing and involved in the regulation of both endochondral resorption and bone remodeling. TNF-alpha and IL-1 are expressed at both very early and late phases in the repair process, which suggests that these cytokines are important in the initiation of the repair process and play important functional roles in intramembraneous bone formation and trabecular bone remodeling.

Animals↗
PubMed2001

Augmented hepatocellular carcinoma progression and depressed Kupffer cell activity in rat cirrhotic livers.

To examine the property of hepatocellular carcinoma (HCC), rat HCC cells were implanted into normal and cirrhotic rat livers. Implanted HCC grew much more progressively in cirrhotic livers than in normal livers. Kupffer cells were decreased profoundly in cirrhotic livers, resulting in markedly impaired phagocytic activity. Furthermore, production of Kupffer cell-related cytokines, such as interleukin-1 beta and tumor necrosis factor-alpha, was decreased profoundly in cirrhotic livers. Our results indicate that liver cirrhosis is a prominent promoting factor in HCC progression, and that markedly depressed Kupffer cell activity may play a role in augmented HCC progression in cirrhotic livers.

Animals↗
PubMed2001

In vitro substrate identification studies for p-glycoprotein-mediated transport: species difference and predictability of in vivo results.

Two different cellular assay models were assessed as in vitro systems for P-glycoprotein (P-gp) substrate identification: cellular accumulation studies with KB-V1, a human MDR1 P-gp-overexpressing multidrug-resistant human epidermoid carcinoma cell line; and transcellular transport studies with L-MDR1 (or L-mdr1a), a human MDR1 (or mouse mdr1a)-transfected porcine renal epithelial cell line. The in vitro-in vivo correlation for P-gp-mediated transport activity was also examined by comparing in vitro data obtained from L-mdr1a cell studies and in vivo data from mdr1a (-/-)/(+/+) CF-1 mice studies for several compounds. The results are summarized as follows: 1) two in vitro assay systems routinely identified the substrate for human MDR1 P-gp-mediated transport with similar quantitative results; 2) in vitro studies with L-MDR1 and L-mdr1a cells demonstrated that the P-gp substrate susceptibility is different between human and mouse for certain compounds (species difference); and 3) in vivo brain concentration ratios of mdr1a (-/-) to (+/+) CF-1 mice, either at a certain time point or up to 60 min, correlated well with the in vitro transcellular transport ratios from L-mdr1a cells (r(2) = 0.968 and 0.926, respectively). This indicates that, at least in mice, the in vitro data are valid predictors of the in vivo contribution of P-gp: the contribution of P-gp to the distribution of the compound to the brain up to 60 min post i.v. administration. These results provide a rationale for predicting in vivo relevance of P-gp in human from in vitro data using human P-gp-expressing cells.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2001

Pesticide poisoning initially suspected as a natural death.

A pesticide poisoning victim suspected initially as having died a natural death was autopsied. The victim was a 47-year-old male. Macroscopically, signs of acute death and, in particular, general erosion in the mucosa of the airways and esophagus were observed. In the gastric contents, which had a pungent smell and a greenish-brown color, 5.00 g/L of propanil, 1.27 g/L of carbaryl, 0.38 g/L of ethylbenzene, and 0.32 g/L of xylene were detected. In the blood (serum), 21.6 mg/L of propanil, 8.1 mg/L of carbaryl, 1.7 mg/L of ethylbenzene, and 4.0 mg/L of xylene were identified. Postmortem methemoglobinemia (45%) was recognized. The cause of death was considered to have been pesticide poisoning; propanil was probably most responsible for his death. The police considered the case to be "death with illness as the suspected cause." By performing an autopsy, however, we were able to clarify that the cause of death was pesticide poisoning.

Carbaryl↗
PubMed2001

Beneficial effect of the active form of vitamin D3 against LPS-induced DIC but not against tissue-factor-induced DIC in rat models.

1Alpha,25-dihydroxyvitamin D3 (active form of vitamin D3; vitamin D3) has been reported to induce the upregulation of thrombomodulin and downregulation of tissue factor (TF) on monocytes. The possibility exists that vitamin D3 prevents the development of disseminated intravascular coagulation (DIC). In particular, monocyte TF production plays an important role in the pathophysiology of DIC in septic patients. We have attempted to determine whether vitamin D3 is effective against DIC in a rat model induced by lipopolysaccharides (LPS) (30 mg/kg, 4 h) or TF (3.75 U/kg, 4 h) using selective hemostatic parameters, markers of organ dysfunction and pathological findings (assessment of glomelular fibrin deposition). Vitamin D3 was administered orally each day at a dose of 2.0 mg/kg/day for 3 days, or low molecular weight heparin (LMWH 200 u/kg; i.v.) was given 10 min before the injection of TF or LPS in each treatment group. Vitamin D3 was effective against DIC in the rat model induced by LPS only, whereas LMWH was effective against DIC in both rat models induced by either TF or LPS. The anti-DIC effect of vitamin D3 was equal to (or more potent than) that of LMWH. The results suggested that vitamin D3 was useful for the treatment of LPS-induced DIC, and that the assessment of a drug's efficacy should be done carefully given the markedly different results obtained according to the agents used to induce DIC.

Administration, Oral↗
PubMed2001

[A point mutation at Arg169 (CGG-->TGG) in hereditary protein C deficiency].

We investigated a 56-year-old Japanese man with protein C deficiency, who was referred to our hospital because of venous sinus thrombosis and pulmonary thromboembolism. Protein C (PC) activity and the corresponding antigen level in plasma were 66% and 106% of the normal values, respectively. Both the activity and antigen levels of protein C were reduced by approximately 50% in plasma from the patient's mother. All exons and their flanking intron regions were amplified by PCR from genomic DNA. Sequencing analysis of the PCR fragments revealed that the patient was heterozygous for a C to T substitution at nucleotide position 6218, resulting in a single amino acid substitution of arginine (CGG) by tryptophan (TGG) at codon 169 of the heavy chain. We analyzed the patient, his mother, and normal controls by a Sac II digestion study of exon 7 and found that the patient and his mother had the same C to T point mutation at base 6218. This mutation could have been responsible for the defective activation of the molecule and the resulting thrombotic disorder. The patient is now being treated with warfarin, and so far no further clinical thrombotic episode has occurred.

DNA Mutational Analysis↗