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Biomedical subjects

M Nishi

Publications and source records attributed to M Nishi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Cyclin E expression, a potential prognostic marker for non-small cell lung cancers.

Cyclin E is a G1 cyclin that has been shown to be one of the key regulators of the G1-S transition and could consequently be a deregulated molecule in tumors. In the present study, we have characterized cyclin E expression by immunohistochemistry in 217 resected non-small cell lung cancers (NSCLCs) and found large variations in cyclin E expression among tumors. High-level cyclin E expression (a cyclin E-labeling index > or =30%), observed in 115 (53%) of 217 NSCLCs, was more frequently found in tumors from smokers than from nonsmokers (P = 0.001), in squamous cell carcinomas than in nonsquamous cell carcinomas (P = 0.0002), and in pT2-4 tumors than in pT1 tumors (P = 0.04) by the chi2 test. Multivariate logistic regression analysis for the correlation between cyclin E expression and various characteristics showed a significant association of high-level cyclin E expression with squamous cell carcinomas (P = 0.005). Patients with tumors having high-level cyclin E expression survived a significantly shorter time than patients with tumors having low-level expression, both among the 151 patients with potentially curatively resected NSCLCs (5-year survival rates, 48 and 63%, respectively; P = 0.03) and the 103 patients with p stage I NSCLCs (5-year survival rates, 57 and 81%, respectively; P = 0.007). High-level cyclin E expression was also a significant and independent unfavorable prognostic factor in both patients with potentially curatively resected NSCLCs (P = 0.01) and in those with p stage I NSCLCs (P = 0.03) by Cox's proportional hazards model analysis. These findings indicate that cyclin E may play a pivotal role for the biological behavior of NSCLCs, and that a high level of cyclin E expression may be a new prognostic marker for NSCLCs.

Aged↗
PubMed2000

Genetic characterization of adenovirus strains isolated from patients with acute conjunctivitis in the city of São Paulo, Brazil.

Genome analysis was carried out on adenovirus strains isolated from patients with acute follicular conjunctivitis in the city of São Paulo, Brazil. Eighteen conjunctival scrapings, collected between December 1993 and March 1994, were analyzed by two methods: a combination of polymerase chain reaction with restriction fragment length polymorphism and viral DNA restriction analysis, carried out using 10 restriction endonucleases: BamHI, BglI, BglII, HindIII, KpnI, SacI, SalI, SmaI, XbaI, and XhoI. Among 11 adenovirus detected by cell culture isolation, nine were Ad8, and two were Ad7. By restriction analysis the Ad8 isolates were typed as two new variants-Ad8/D11 (seven of nine samples) and Ad8/D12 (two of nine samples). Ad7 isolates were identified as a subtype of the widespread genome type Ad7b and the virulent type Ad7h, a predominant genome type circulating in Argentina, Chile, and Uruguay but absent in Brazil until 1991.

Acute Disease↗
PubMed2000

Changes in dopamine transporter and c-Fos expression in the nucleus accumbens of alcohol-tolerant rats.

BACKGROUND: We have shown that neurochemical functions of 5-HT3 receptors in regulating dopamine (DA) release in the nucleus accumbens (ACC) after alcohol exposure compensate for the dysfunction of serotonergic activity to restore the original properties in processing alcohol tolerance, and that the development of alcohol dependence may be mediated by ACC 5-HT3 receptors. In the present study, the effects of chronic alcohol consumption on the functions of the dopamine transporter (DAT) and the expression of c-Fos proteins were investigated using in vivo brain microdialysis and immunocytochemistry. METHODS: Perfusion of cocaine and 1-(2-Bis-(4-fluorophenyl) methoxy) ethyl)-4-(3-phenylpropyl) piperizine (GBR 12909) through the microdialysis probe membrane increased the extracellular levels of DA in ACC of alcohol-treated rats that had developed alcohol tolerance by drinking 10% EtOH for 30 days. RESULTS: The magnitudes of DA reuptake or DAT inhibitors, cocaine, and GBR 12909 that induced DA availability in the ACC were significantly higher in alcohol-treated rats than in controls. When compared with control rats, the alcohol-treated rats exhibited higher levels of DA and its metabolite, DOPAC, in the ACC. Increased expression of the c-Fos-like protein was found in the ACC of alcohol-treated rats. These results show that (1) chronic alcohol consumption desensitizes or decreases the DAT of DA terminals in the ACC and that (2) EtOH causes cellular hyperexcitability of ACC dopaminergic neurons with increased Fos expression during alcohol tolerance. CONCLUSION: The findings suggested that an abnormality of the dopaminergic neurons in the ACC that are involved with DAT dysfunction is associated with the development of alcohol tolerance.

Alcoholism↗
PubMed2000

Prognostic significance of p27KIP1 protein and ki-67 growth fraction in non-small cell lung cancers.

We immunohistochemically examined specimens of 215 surgically resected non-small cell lung cancers (NSCLCs) for p27KIP1 protein (p27) expression and the growth fraction determined by the Ki-67 labeling index (LI). The NSCLCs analyzed showed considerable heterogeneity in both p27 and Ki-67 LIs; 25 of 207 (13%) lacked p27 expression (p27 LI < 5%), and 116 of 215 (54%) showed a high Ki-67 LI (>30%). The p27 LI was not significantly associated with the Ki-67 LI. A chi2 test showed that loss of p27 expression was inversely correlated with smoking (P = 0.01) and that a high Ki-67 LI was significantly associated with male gender, squamous cell carcinoma histology, and smoking (P < 0.0001 each). Prognostic values of p27 and Ki-67 expression were evaluated in 109 tumors of postsurgical pathological stages I and II. Patients with tumors lacking p27 expression survived for a significantly shorter time than patients with tumors expressing p27 (5-year survival rates, 38% and 68%, respectively; P = 0.02). Patients with tumors having a high Ki-67 LI survived for a significantly shorter time than patients with tumors having a low Ki-67 LI (5-year survival rates, 48% and 78%, respectively; P = 0.005). Multivariate analysis showed that loss of p27 expression tended to be an unfavorable prognostic factor (P = 0.054), whereas a high Ki-67 LI was a significant and independent unfavorable prognostic factor (P = 0.004). When analyzed by cell types, loss of p27 expression was a significant and independent unfavorable prognostic factor in squamous cell carcinomas (P = 0.01), whereas a high Ki-67 LI was a significant and independent unfavorable prognostic factor in nonsquamous cell carcinomas (P = 0.007). We further evaluated the importance of p27 expression in clinical outcome in combination with the Ki-67 LI and ras p21 protein (ras) expression, which we previously reported as an important prognostic factor in NSCLCs. Patients with tumors lacking p27 expression and having a high Ki-67 LI survived for a significantly shorter time than those with tumors expressing p27 and having a high Ki-67 LI (5-year survival rates, 17% and 52%, respectively; P = 0.003). Patients with p27-negative and ras-positive tumors survived for a significantly shorter time than those with both p27- and ras-positive tumors (5-year survival rates, 0% and 38%, respectively; P < 0.0001). These results indicate the pivotal roles of p27 and Ki-67 expression in the clinical outcome of NSCLCs.

Adult↗
PubMed2000

[Corticosteroid receptor and stress].

Adrenal corticosteroids readily enter the brain and exert markedly diverse effects, such as stress response of the target neural cells. These effects are regulated via two receptor systems, the mineralocorticoid receptor (MR; type I corticosteroid receptor) and the glucocorticoid receptor (GR; type II corticosteroid receptor), both of which are ligand-dependent transcription factors. MR is localized mainly in the hippocampus, and GR is distributed throughout the brain. MR and GR, however, are highly colocalized in the hippocampus, which is a target of the stress hormone and an especially plastic and vulnerable region of the brain. MR has a high affinity for corticosterone/cortisol, a common endogenous ligand for MR and GR, and is extensively bound at low levels of circulating corticosterone/cortisol. GR has a lower affinity and is extensively bound at high levels of circulating corticosterone/cortisol. These findings suggest that MR plays major roles under physiological conditions, whereas GR is mainly effective at high concentrations of corticosterone/cortisol, such as stressful conditions. The interactions of MR and GR in the hippocampal regions could be important for regulating stress response in the brain.

Animals↗
PubMed2000

[Studies on chemical constituents of Peucedanum medium Dunn var. garcile Dunn ex Shan at Sheh].

OBJECTIVE: To study the chemical constitutents in Peucedanum medium var. gracile distributed in Guangxi. METHOD: Chromatography and spectral analysis were used to isolated and elucidate the constituents. RESULT: Eight compounds were isolated from the root of P. medium var. gracile and elucidated as isoimperatorin, phellopterin, bergapten, oxypeucedanin hydrate, byakangelicin beta-sitosterol, hamaudol and mannitol. CONCLUSION: Seven compounds were obtained from this plant for the first time.

5-Methoxypsoralen↗
PubMed1999

Abnormal features in skeletal muscle from mice lacking mitsugumin29.

Physiological roles of the members of the synaptophysin family, carrying four transmembrane segments and being basically distributed on intracellular membranes including synaptic vesicles, have not been established yet. Recently, mitsugumin29 (MG29) was identified as a novel member of the synaptophysin family from skeletal muscle. MG29 is expressed in the junctional membrane complex between the cell surface transverse (T) tubule and the sarcoplasmic reticulum (SR), called the triad junction, where the depolarization signal is converted to Ca(2+) release from the SR. In this study, we examined biological functions of MG29 by generating knockout mice. The MG29-deficient mice exhibited normal health and reproduction but were slightly reduced in body weight. Ultrastructural abnormalities of the membranes around the triad junction were detected in skeletal muscle from the mutant mice, i.e., swollen T tubules, irregular SR structures, and partial misformation of triad junctions. In the mutant muscle, apparently normal tetanus tension was observed, whereas twitch tension was significantly reduced. Moreover, the mutant muscle showed faster decrease of twitch tension under Ca(2+)-free conditions. The morphological and functional abnormalities of the mutant muscle seem to be related to each other and indicate that MG29 is essential for both refinement of the membrane structures and effective excitation-contraction coupling in the skeletal muscle triad junction. Our results further imply a role of MG29 as a synaptophysin family member in the accurate formation of junctional complexes between the cell surface and intracellular membranes.

Amino Acid Sequence↗
PubMed1999

Structure and stability of the consecutive stereoregulated chiral phosphorothioate DNA duplex.

The duplex structures of the stereoregulated phosphorothioate DNAs, [R(p),R(p)]- and [S(p),S(p)]-[d(GC(ps)T(ps)ACG)] (ps, phosphorothioate; PS-DNA), with their complementary RNA have been investigated by combined use of (1)H NMR and restrained molecular dynamics calculation. Compared to those obtained for the unmodified duplex structures (PO-DNA.RNA), the NOE cross-peak intensities are virtually identical for the PS-DNA.RNA hybrid duplexes. The structural analysis on the basis of the NOE restraints reveals that all of the three DNA.RNA duplexes take a A-form conformation and that there is no significant difference in the base stacking for the DNA.RNA hybrid duplexes. On the other hand, the NOE cross-peak intensities of the protons around the central T(ps)A step of the PS-DNA.DNA duplexes are apparently different from those of PO-DNA. DNA. The chemical shifts of H8/6 and H1' at the T(ps)A step are also largely different among PS-DNA.DNAs and PO-DNA.DNA, suggesting that the DNA.DNA structure is readily changed by the introduction of the phosphorothioate groups to the central T(p)A step. The structure calculations indicate that all of these DNA.DNA duplexes are B-form although there exist some small differences in helical parameters between the [R(p),R(p)]- and [S(p),S(p)]PS-DNA.DNA duplexes. The melting temperatures (T(m)) were determined for all of the duplexes by plotting the chemical shift change of isolated peaks as a function of temperature. For the PS-DNA.RNA hybrid duplexes, the [S(p),S(p)] isomer is less stable than the [R(p),R(p)] isomer while this trend is reversed for the PS-DNA.DNA duplexes. Consequently, although the PS-DNA.RNA duplexes take the similar A-form structure, the duplex stability is different between PS-DNA.RNA duplexes. The stability of the DNA.RNA duplexes may not be governed by the A-form structure itself but by some other factors such as the hydration around the phosphorothioate backbone, although the T(m) difference of the DNA.DNA duplexes could be explained by the structural factor.

DNA↗
PubMed1999

Relationship between urinary cadmium and mortality among inhabitants living in a cadmium polluted area in Japan.

A 15 year follow-up study of 3119 inhabitants living in a cadmium polluted area was conducted to investigate the influence of environmental cadmium exposure on the mortality. The cumulative survival curves of the subjects with urinary cadmium concentration > or = 10 microg/g creatinine was lower than that of the subjects with < 10 microg/g creatinine in the men aged 50-59 and 60-69 years and in the women aged 60-69 and 70-79 years. In the men aged 50-69 years and the all aged women, the cumulative survival curves became lower in proportion to the increase of urinary cadmium concentration, when the subjects were divided into four groups according to the amount of urinary cadmium concentration (< 5, 5-9.9, 10.1-19.9, > or = 20 microg/g creatinine). These results suggested a dose response relationship between cadmium exposure and mortality.

Aged↗
PubMed1999

Down-regulation of ACTH and glucocorticoid receptor immunoreactivity in hypothalamic arcuate neurons after adrenalectomy in the rat.

The expression of glucocorticoid receptor (GR) in rat adrenocorticotropin (ACTH)-containing neurons in rat brain was immunohistochemically investigated. ACTH-containing cell bodies were found mainly in the arcuate nucleus. Most of these neurons exhibited GR immunoreactivities in their nuclei. ACTH-containing nerve fibers were distributed in the bed nucleus of the stria terminalis, periventricular nucleus, retrochiasmatic nucleus, parvocellular part of paraventricular nucleus and dorsomedial hypothalamic nucleus. After adrenalectomy there was a marked decrease of ACTH immunoreactivity, as well as GR immunoreactivity, in neurons of the arcuate nucleus, but ACTH immunoreactivity in the fibers was not affected. These results indicate that glucocorticoids up-regulate ACTH and GR production in hypothalamic arcuate neurons, but that glucocorticoid-induced changes could be delayed in the fibers derived from these neurons.

Adrenal Glands↗
PubMed1999

Nociceptin system plays a role in the memory retention: involvement of naloxone benzoylhydrazone binding sites.

We investigated the role of nociceptin system in learning and memory in mice. The deficiency of nociceptin receptors and nociceptin itself did not affect the alternation behavior in the Y-maze test. In the passive avoidance test, the step-through latencies of nociceptin receptor knockout mice were longer than those of wild-type mice. Nociceptin shortened the step-through latency in wild-type mice. This impairment on passive avoidance task was reversed by naloxone benzoylhydrazone (NalBzoH), indicating that the amnesic effects of nociceptin may be mediated through the NalBzoH recognition sites. These suggest that nociceptin system plays an important role in the memory retention of passive avoidance task, and NalBzoH-recognized sites are involved in nociceptin-induced impairment of the memory retention.

Animals↗
PubMed1999

RhoN, a novel small GTP-binding protein expressed predominantly in neurons and hepatic stellate cells.

A cDNA encoding a novel member of the small molecular weight GTP-binding protein (small G-protein) superfamily was cloned from rat spinal cord. The deduced amino acid sequence was highly homologous with those of so-far-known Rho proteins. Rho proteins were reported to alter many important cellular functions including formation of both actin stress fibers and focal adhesions. RNA blot hybridization and in situ hybridization analyses indicated that the novel small G-protein is expressed specifically in neurons in the brain and spinal cord and also in hepatic stellate cells. Based on the sequence similarity and neuron-specific expression in the brain, this protein was named RhoN. Unlike classical Rho proteins, RhoN was not susceptible to the ADP-ribosylation reaction by C3 botulinum toxin. Accordingly, RhoN seemed to be specifically involved in neuronal and hepatic functions as a C3 toxin-insensitive member of the Rho subfamily. Then, a mouse genomic DNA segment containing the RhoN gene was cloned. The locus was mapped on the mouse chromosome 11C-D. The sequence data showed that the protein-coding sequence for RhoN is divided by 4 introns, and that the defined 5 exons may encode intramolecular domains serving for different functions.

Adenosine Diphosphate Ribose↗
PubMed1999

Agonist- and antagonist-induced plasticity of rat 5-HT1A receptor in hippocampal cell culture.

We examined the response and regulation of 5-HT1A receptor on hippocampal cultured fetal neurons grown in the absence of serotonin and steroids using three experimental designs: 1) functional response using an antibody against phosphorylated cyclic adenosine monophosphate response element binding protein (pCREB); 2) transcriptional regulation using in situ hybridization; and 3) translational expression using antipeptide 5-HT1A receptor antibody. Pretreatment of cultured hippocampal cells with the agonist 8-hydroxy-2-(di-N-propylamino)-tetralin (8-OH-DPAT) (10(-8) M) or ipsapirone (IPS) (10(-9) M) for 10 min blocked the forskolin-stimulated increase in pCREB immunoreactivity. In situ hybridization radioautography revealed that IPS (10(-9) M) decreased the 5-HT1A receptor mRNA expression (-33%) after a 24-h treatment. The decrease in 5-HT1A receptor mRNAwas accompanied by a change in protein immunoreactivity using a 5-HT1A receptor antipeptide antibody. Computer-assisted morphometric analyses showed a reduction in the 5-HT1A receptor immunoreactive (IR) intensity as compared to control 24 h after treatment with 8-OH-DPAT (10(-7)-10(-12) M) and IPS (10(-9) M). Thus, fetal hippocampal neurons have a functional 5-HT1A receptor that is downregulated at both the transcription and translation levels. In addition, we found increased 5-HT1A receptor-IR intensity (+17% approximately +39%) 24 h after treatment with the antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane carboxamide (WAY 100635) (10(-7)-10(-12) M). Our results indicate that the 5-HT1A receptor is sensitive to both agonists (downregulation) and antagonists (upregulation) in hippocampal fetal neurons grown in the absence of serotonin and steroids.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1999

Immunolocalization of mitsugumin29 in developing skeletal muscle and effects of the protein expressed in amphibian embryonic cells.

The temporal appearance and subcellular distribution of mitsugumin29 (MG29), a 29-kDa transmembrane protein isolated from the triad junction in skeletal muscle, were examined by immunohistochemistry during the development of rabbit skeletal muscle. MG29 appeared in the sarcoplasmic reticulum (SR) in muscle cells at fetal day 15 before the onset of transverse tubule (T tubule) formation. In muscle cells at fetal day 27, in which T tubule and triad formation is ongoing, both SR and triad were labeled for MG29. In muscle cells at newborn 1 day, the labeling of the SR had become weak and the triads were well developed and clearly labeled for MG29. Specific and clear labeling for MG29 was restricted to the triads in adult skeletal muscle cells. When MG29 was expressed in amphibian embryonic cells by injection of the cRNA, a large quantity of tubular smooth-surfaced endoplasmic reticulum (sER) was formed in the cytoplasm. The tubular sER was 20-40 nm in diameter and appeared straight or reticular in shape. The tubular sER was formed by the fusion of coated vesicles [budded off from the rough-surfaced endoplasmic reticulum (rER)] and vacuoles of rER origin. The present results suggest that MG29 may play important roles both in the formation of the SR and the construction of the triads during the early development of skeletal muscle cells.

Amphibians↗
PubMed1999

Molecular scanning for mutations in the melanocortin-4 receptor gene in obese/diabetic Japanese.

Decreased function of the melanocortin-4 receptor (MC4R) was reported to cause late-onset obesity and insulin resistance in rodents. Thus mutations in the MC4R gene drew strong attention as a possible cause of obesity and diabetes. We screened for mutations in the MC4R gene in extremely obese [body mass index (BMI) > or = 35 kg/m2] Japanese with diabetes by direct sequencing. A heterozygous mutation (V103I) was detected in one case (2.0 %), however the frequency was not significantly different from that in non-obese (BMI < or = 24 kg/m2) and non-diabetic subjects (2.7 %). No other mutations were detected. These results suggest that mutations including V103I in the MC4R gene are not a major cause of obesity or diabetes in Japanese.

Animals↗
PubMed1999

Components of the ether-insoluble resin glycoside fraction from the seed of Cuscuta australis.

An ether-insoluble resin glycoside fraction was obtained from the seeds of Cuscuta australis. Identification and characterization of alkaline hydrolysis products by means of GC, FABMS, and 1H, 13C, and 2D NMR revealed the material to be composed of three new glycosidic acids, cuscutic acids A1-A3 (1-3); triglycosides with (11S)-jalapinolic or (11S)-convolvulinolic acid as the aglycon; and acetic, isobutyric, (2S)-2-methylbutyric, tiglic, and (2R,3R)-nilic acids. The resin glycoside is considered to be a complex mixture of glycosidic ester-type oligomers (up to heptamers) with a core consisting of a number of the above cuscutic acids each acylated with one or two carboxylic acid moieties.

Carbohydrate Sequence↗
PubMed1999

Distribution of glucocorticoid receptor immunoreactivity in gastric mucosa of normal and adrenalectomized rats.

Glucocorticoids have many effects in the stomach. It is well known that glucocorticoids function via the glucocorticoid receptor (GR). In this study, GR immunoreactivity in the gastric mucosa of normal and adrenalectomized (ADX) rats was examined immunohistochemically by using specific polyclonal antibodies against rat GR. In the gastric mucosa of normal rats, GR immunoreactivity was observed in the nuclei of morphologically identified parietal cells. Double immunohistochemical staining for GR and parietal cell, anti-parietal cell antibody-positive cells also had positive immunoreactions for GR. In the gastric mucosa of ADX rats, GR immunoreactivity was diminished in the nuclei of parietal cells but weak immunoreactivity was still observed. These results suggest that parietal cells in the gastric mucosa of rats are directly regulated by glucocorticoids via its receptors. Nuclear GR immunoreactivity in gastric parietal cells is thought to depend on the circulating ligands.

Adrenalectomy↗