Mu Type Research Articles

Histological Mixed-Type Early Gastric Cancer Is an Independent Risk Factor for Lymph Node Metastasis: Presidential Poster

Introduction: Endoscopic submucosal dissection (ESD) is a promising method for early gastric cancer (EGC). In certain ESD cases, additional surgery is to be considered after the histological investigation of the obtained specimen. However, management of lesions which have differentiated and undifferentiated carcinoma (mixed-type) is still unclear. The aim of the study is to clarify the clinicopathological significance of histological mixed-type EGC. Methods: We retrospectively reviewed 593 consecutive EGC lesions in 528 subjects treated in our hospital (age (mean±SE) 69.9±0.4), male/female 410/183). 362 were underwent ESD and 231 were underwent gastrectomy. Histological findings of the lesions were classified into following four groups; purely undifferentiated type (PD), mixed-type with predominantly differentiated part (MD), purely undifferentiated type (PU), and mixed-type with predominantly undifferentiated part (MU). We investigated the correlation between these types and following findings; location of the tumor, macroscopic type, tumor size, presence of lymphatic and vascular duct invasion, submucosal invasion depth, and the prevalence of lymph node metastasis. Among subjects underwent gastrectomy, potential risk factor for lymph node metastasis including macroscopic type, tumor size, submucosal invasion depth, and the histological type (pure/mixed) were evaluated by multivariate logistic regression analysis. Results: Subjects with PU type cancer were younger and held more female subjects than those with MU type (p < 0.001, p < 0.05). In macroscopic type, MD and PU type included more depressed lesions than PD and MU type, respectively (p < 0.0001, p < 0.05). Diameter of lesions of MD type were larger than that of PD type (p < 0.0001). MD and MU type were significantly associated with submucosal invasion than PD and PU type, respectively (p < 0.0001, p < 0.001) and this association was observed even among the lesion less than 20mm, respectively (p < 0.001, p < 0.05). Multivariate analysis revealed that mixed-type (odds ratio (OR) =3.1, 95% confidence interval (95%CI):1.2-8.3, p=0.02) and the invasion depth (OR=5.2, 95%CI: 1.6-2.3, p=0.01) were significant risk factor for lymph node metastasis. Conclusion: Histological mixed-type EGC is an independent risk factor for lymph node metastasis regardless of tumor size. When ESD is performed for EGC, histological confirmation of the resected tumor especially for pure or mixed type should be considered.

DISTINGUISHABILITY OF NEUTRINO FLAVORS THROUGH THEIR DIFFERENT SHOWER CHARACTERISTICS

We propose a new flavor identification method to distinguish mu and tau type ultra high energy cosmic neutrinos (UHECN). Energy loss of leptons in matter is an important information for the detection of neutrinos originated from high energy astrophysical sources. 50 years ago, Askaryan proposed to detect Cherenkov radiowave signals emitted from the negative charge excess of neutrino-induced particle shower. The theory of Cherenkov radiation under Fraunhofer approximation has been widely studied in the past two decades. However, at high energies or for high density materials, electromagnetic shower should be elongated due to the Landau-Pomeranchuck-Migdal (LPM) effect. As such the standard Fraunhofer approximation ceases to be valid when the distance between the shower and the detector becomes comparable with the shower length. Monte Carlo simulations have been performed recently to investigate this regime. Here we adopt the deduced relationship between the radio signal and the cascade development profile to investigate its implication to lepton signatures. Our method provides a straightforward technique to identify the neutrino flavor through the detected Cherenkov signals.

A Patient With Dysphagia Associated With Opioid Medication

A 40-year-old male visited Asan Medical Center complaining of dysphagia, which he had experienced for about six months. His medical history indicated that he had suffered from pulmonary tuberculosis with destructive lung, and took various medications to control his chronic cough. He denied any symptom of heartburn or acid regurgitation. Upper endoscopy findings were normal. The barium esophagogram showed no definite abnormalies. However, esophageal manometry revealed nutcracker esophagus with a mean distal esophageal amplitude of 213.0 mmHg (resting lower esophageal sphincter pressure was 22.9 mmHg). He was taking many medications as needed, including codeine 20 mg, to control his frequent cough (more than 10 times/day). He also complained of chronic constipation after taking too many codeine tablets. At his second visit, he was instructed to decrease the use of codeine to 3 times per day. After reducing the dosage of codeine, the dysphagia improved. Four months later, a follow-up esophageal manometry was performed and it showed normal peristalsis without evidence of nutcracker esophagus, with a mean distal esophageal amplitude of 161.6 mmHg (resting lower esophageal sphincter pressure was 27.1 mmHg). Experimental evidence of opioid-induced esophageal dysmotility has been provided in several papers.1,2 However, clinical manifestations of this condition were recently presented only in case reports from the Mayo clinic.3,4 The lower esophageal sphincter and distal esophageal body are known to be vulnerable to chronic use of opioid medications with mu type opioid agonist function.1,3 The reason for this is not perfectly clear, however, the nitric oxide pathway is thought to be involved.3,4

Renal and vascular glutathione S-transferase μ is not affected by pharmacological intervention to reduce systolic blood pressure

Our previous studies demonstrated reduced rat glutathione S-transferase mu type 1 (Gstm1) expression in stroke-prone spontaneously hypertensive rats (SHRSPs), when compared with the normotensive Wistar-Kyoto rat. This study investigated the effects of angiotensin II type 1 receptor blocker (ARB) and a diuretic/vasodilator combination on the expression levels of rat Gstm1 and other Gstm isoforms. Antihypertensive treatments of young and mature SHRSPs with an ARB and a diuretic/vasodilator combination improved SBP but did not affect the expression levels of Gstm1. Although Gstm1 is a member of a family of highly homologous genes, with the exception of Gstm2, there was no evidence for compensatory increase in expression of other Gstm isoforms. In contrast, we observed reduced expression of several other Gstm isoforms in untreated SHRSPs. Untreated SHRSPs demonstrated increased renal and vascular oxidative stress, both of which were not significantly affected by the antihypertensive treatments. Untreated SHRSPs scored significantly higher when assessed for renal histopathological damage, and this was improved by antihypertensive treatments. These results suggest that reduced Gstm1 expression in SHRSPs is due to strain-dependent genetic abnormalities, playing a causative role in the development of hypertension, probably through oxidative stress pathway. Renal changes occur as a consequence of increased blood pressure and can be improved when treated with antihypertensive drugs. In silico comparative genome analysis combined with expression studies in rat and human vascular tissue revealed that there are possible four human homologues (GSTM1, GSTM2, GSTM4 and GSTM5) for rat Gstm1.

Proteomic Analysis of the Rat Ovary Following Chronic Low-Dose Exposure to 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD)

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitously distributed endocrine-disrupting chemical and reproductive toxicant. In order to elucidate low-dose TCDD-mediated effects on reproductive or endocrine functions, female Sprague-Dawley rats were orally administered various concentrations (20, 50, or 125 ng/kg once weekly) TCDD for 29 wk. A proteomic analysis of the ovaries by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry showed distinct changes in the levels of several proteins that are relevant markers of TCDD toxicity. Serum estradiol (E2) levels of TCDD-treated animals were markedly lower than control. There were no significant differences in bone mineral density (BMD) of femurs. The body weight of the 125-ng/kg TCDD group was significantly decreased relative to control and there was also a significant reduction in absolute and relative ovarian weights. Expressions of selenium binding protein 2, glutathione S-transferase mu type 3, Lrpap1 protein, NADPH, and peptidylprolyl isomerase D were upregulated, while prohibitin and N-ethylmaleimide-sensitive factor expression levels were downregulated. Data provide further insight into the mechanisms by which TCDD disrupts ovarian function by indicating which differential protein expressions following low-dose TCDD exposure.

An association between resistant hypertension and the null GSTM1 genotype

Reduction in expression levels of glutathione S-transferase (GST) mu type 1 (GSTM1) in stroke-prone spontaneously hypertensive rats has recently been reported. GSTM1 genotype was evaluated in 49 patients with resistant hypertension and compared with selected patients with controlled hypertension (n=232) and healthy participants (n=110). Null GSTM1 genotype occurred more frequent in patients with resistant hypertension than those with controlled hypertension (57.1 vs 39.7%; P=0.03; RR 1.96; 95% CI 1.04-3.69) suggesting that null GSTM1 genotype may predispose to resistant hypertension.

Glutathione S-transferase variants and hypertension

Glutathione S-transferases are involved in defences against oxidative stress. We have recently demonstrated reduced expression of glutathione S-transferase mu type 1 (Gstm1) in a rat model of hypertension. Here, we examine the association between GSTM variants and hypertension in human. We screened 83 patients with hypertension and 46 controls for single nucleotide polymorphisms in GSTM genes by TaqMan single nucleotide polymorphism genotyping assays and DNA sequencing. We then genotyped 753 trios from the Medical Research Council British Genetics of Hypertension Study transmission disequilibrium test cohort for 10 single nucleotide polymorphisms and the GSTM1 deletion and examined renal GSTM expression in a cohort of 27 hypertensive and 18 normotensive subjects. Finally, we attempted to replicate our findings in 1675 cases and 1654 controls from the Medical Research Council British Genetics of Hypertension Study case-control cohort. We identified two major linkage disequilibrium blocks including GSTM4/GSTM2 and GSTM5/GSTM3 separated by the GSTM1 gene. In the British Genetics of Hypertension transmission disequilibrium test resource, a single nucleotide polymorphism in the 3' region of GSTM5 (rs11807) was found to be associated with hypertension (P = 0.01) with the T-allele being over-transmitted to hypertensive offspring. GSTM5 mRNA expression was found to be reduced in kidney tissue of subjects homozygous for the T-allele of rs11807 as compared to C-allele homozygous and CT heterozygous subjects (P = 0.02). Nevertheless, rs11807 was not associated with hypertension in the British Genetics of Hypertension case-control cohort (P = 0.61). Our studies do not provide an evidence of an association of GSTM gene variants with hypertension in humans. They, however, illustrate the essential role of replication of initial results in a second cohort.

Characterization and pharmacological actions of tecostanine, an alkaloid of Tecoma stans.

Tecostanine (1) was isolated from Tecoma stans leaves. Its sterochemistry was elucidated as well as its antihyperglycemic activity and its affinity to opioid and nicotinic receptors. The oxalate salt of 1 did not significantly affect blood glucose levels in normoglycaemic and hyperglycaemic rats. It did not appear to interact with opioid receptors (mu type) and showed only moderate affinity to the nicotinic receptor.

Zero-Temperature Dynamics of ±J Spin Glasses¶and Related Models

We study zero-temperature, stochastic Ising models sigma(t) on a d-dimensional cubic lattice with (disordered) nearest-neighbor couplings independently chosen from a distribution mu on R and an initial spin configuration chosen uniformly at random. Given d, call mu type I (resp., type F) if, for every x in the lattice, sigma(x,t) flips infinitely (resp., only finitely) many times as t goes to infinity (with probability one) --- or else mixed type M. Models of type I and M exhibit a zero-temperature version of ``local non-equilibration''. For d=1, all types occur and the type of any mu is easy to determine. The main result of this paper is a proof that for d=2, plus/minus J models (where each coupling is independently chosen to be +J with probability alpha and -J with probability 1-alpha) are type M, unlike homogeneous models (type I) or continuous (finite mean) mu's (type F). We also prove that all other noncontinuous disordered systems are type M for any d greater than or equal to 2. The plus/minus J proof is noteworthy in that it is much less ``local'' than the other (simpler) proof. Homogeneous and plus/minus J models for d greater than or equal to 3 remain an open problem.

Frequency of homozygous null mutation at the glutathione-s-transferase Ml locus in some populations of Orissa, India

GSTM1, one of the mu type glutathione-s-transferase isozymes in human, has been observed to be inherited dominantly, and the polymorphism of this gene can be detected by polymerase chain reaction (PCR). In this report we have determined the frequency of a homozygous deletion mutation of the GSTM1 gene in some populations of the Sundergarh District in Orissa, India. About 24% of unrelated individuals (n = 72) were detected to carry this deletion mutation in homozygous form. Possible implications of this homozygous deletion are discussed.

How opioids inhibit GABA-mediated neurotransmission.

The midbrain region periaqueductal grey (PAG) is rich in opioid receptors and endogenous opioids and is a major target of analgesic action in the central nervous system. It has been proposed that the analgesic effect of opioids on the PAG works by suppressing the inhibitory influence of the neurotransmitter GABA (gamma-aminobutyric acid) on neurons that form part of a descending antinociceptive pathway. Opioids inhibit GABA-mediated (GABAergic) synaptic transmission in the PAG and other brain regions by reducing the probability of presynaptic neurotransmitter release, but the mechanisms involved remain uncertain. Here we report that opioid inhibition of GABAergic synaptic currents in the PAG is controlled by a presynaptic voltage-dependent potassium conductance. Opioid receptors of the mu type in GABAergic presynaptic terminals are specifically coupled to this potassium conductance by a pathway involving phospholipase A2, arachidonic acid and 12-lipoxygenase. Furthermore, opioid inhibition of GABAergic synaptic transmission is potentiated by inhibitors of the enzymes cyclooxygenase and 5-lipoxygenase, presumably because more arachidonic acid is available for conversion to 12-lipoxygenase products. These mechanisms account for the analgesic action of cyclooxygenase inhibitors in the PAG and their synergism with opioids.

Predominance of sterile immunoglobulin transcripts in a female phenotypically resembling Bruton's agammaglobulinemia

The transcription pattern of the heavy chain immunoglobulin gene locus was analyzed in a 6-month-old female with agammaglobulinemia characterized by the absence of mature B cells in peripheral blood, arrested B cell development in the bone marrow and lack of germinal center development. DNA sequencing provided no evidence of mutations within the coding region of the Bruton's tyrosine kinase gene. Polymerase chain reaction-generated cDNA libraries from blood and bone marrow were screened initially using JH and CH oligodeoxynucleotide probes and VH family-specific probes. Only 10% of the transcripts constituted mature VDJC mu recombinations. Ninety percent of the cDNA were sterile immunoglobulin transcripts comprised of: DJC mu (DH-JHC mu), JC mu (JH-C mu), EC mu (enhancer spliced to C mu), SC mu and IC mu [corresponding to switch (S) and intron (I) regions spliced to C mu]. In the mature immunoglobulin transcripts, VH use indicated germline expression with little evidence of somatic mutation. All cDNA were of the C mu type. Different D segments, D-D joining events and unknown D-like elements were noted in the DJC mu and VDJC mu transcripts. This pattern of immunoglobulin rearrangements, along with the phenotypic cell surface antigen characteristics (CD19-), suggest that an earlier arrest in B cell development than is characteristic of Bruton's X-linked agammaglobulinemia has occurred in this patient.

A microwave μSR spectrometer

A microwave-μSR (μWμSR) spectrometer has been developed which operates in the frequency region of 1–2 GHz. The spectrometer geometry is that of longitudinal field (LF)μSR and is typically used in time integral measurements. The high frequency of this instrument distinguishes it from the currently used RFμSR spectrometers and allows high field measurements to be made for normal Mu type systems. This allows one to avoid low field broadening mechanisms that may be present, either from electronic spin-lattice relaxation or nuclear hyperfine interactions.

Glutathione-linked detoxification pathway in normal and malignant human bladder tissue.

This study compares the levels of glutathione (GSH) and GSH-dependent detoxification enzymes, which have been implicated in anti-cancer drug resistance, in paired normal and malignant human bladder tissues, a tumor with high incidence of inherent drug resistance. Although the mean GSH transferase (GST) activity did not differ significantly in normal and neoplastic bladder tissues, this enzyme activity was relatively higher in tumor tissues of five out of ten patients as compared with corresponding normal tissues. Similarly, the mean GSH content and GSH reductase activity did not differ significantly between normal and neoplastic bladder tissues. On the other hand, the mean GSH peroxidase activity towards cumene hydroperoxide and catalase activity in bladder tumors was higher by about 1.5 and 1.4 times, respectively (P < 0.05), compared with those of normal tissues. GST isoenzymes corresponding to the three major classes (alpha, mu and pi) were expressed in every normal bladder tissue examined in the present study. Overexpression of GST pi was observed in 60% of the bladder tumors, whereas alpha and mu type GST proteins in tumor tissues were lower at frequencies of 62.5% and 37.5%, respectively, compared with the corresponding normal tissues. These results suggest that (a) elevated levels of GSH peroxidase, catalase and GST pi in human bladder tumors may contribute, at least in part, to the intrinsic drug resistance of this neoplasm and (b) anti-oxidative enzymes GSH peroxidase and/or catalase may represent markers for this neoplasia, although a large number of tissue specimens must be analyzed to validate this hypothesis.

Site-specific HU binding in the Mu transpososome: conversion of a sequence-independent DNA-binding protein into a chemical nuclease.

HU is a small, basic, sequence-independent DNA-binding protein capable of engineering DNA deformations required for the formation of higher order nucleoprotein structures. One such complex is the Mu Type 1 transpososome, where the ends of Mu are stably synapsed by a tetramer of Mu A and cleaved at their 3' ends. HU is believed to play a critical role in transpososome assembly, which requires the communication of the two Mu ends and the transpositional enhancer. Although footprinting studies have clearly defined the DNA regions bound by Mu A, no protection could be ascribed to the HU protein by DNAse I, MPE.Fe(II) or hydroxyl radical methods (Lavoie et al. 1991). To directly probe HU interactions with the transpososome DNA, we have coupled HU to a DNA cleavage reagent, iron-EDTA, and report here the first HU "footprint". HU-nuclease cleavage was detectable at specific sites within an 83-bp spacer DNA separating the left-end-most L1 site from its neighboring L2 site. This HU binding was specific since it could not be competed with 10-fold excess supercoiled DNA. We postulate that HU promotes the formation of a tight DNA bend or loop in this region which facilitates the communication of Mu A monomers during complex assembly. This method may prove generally useful for the localization of sequence-independent DNA-binding proteins on DNA and within higher oder nucleoprotein structures.

Synthesis and binding characteristics of the highly delta-specific new tritiated opioid peptide, [ 3H] deltorphin II

A radiolabelled form of deltorphin II was synthesized by catalytic tritiation using [p-IPhe 3]-deltorphin II as a precursor. The ligand labels rat brain membranes with a K d value of 1.9 nM, and the B max was found to be 92 fmol/mg protein. This new tritiated ligand exhibits high affinity for the delta opioid binding site, whereas its binding to the mu type is weak and extremely low for the kappa type. Mu/delta and kappa/delta selectivity ratios were about 900 and 10000, respectively. The highly delta selective binding properties of this new radioligand suggest that it could serve as an excellent tool for investigating the delta opioid receptors in various species.

Structural aspects of a higher order nucleoprotein complex: induction of an altered DNA structure at the Mu-host junction of the Mu type 1 transpososome.

The Mu in vitro strand transfer reaction proceeds via two stable higher order nucleoprotein complexes, the Type 1 and Type 2 transpososomes. The Mu A protein is responsible for the structural and functional integrity of the Type 1 transpososome. We have investigated the quaternary structure of the Mu A protein within this complex by chemical cross-linking experiments and found that the basic structural unit is an A tetramer. Three Mu A binding sites in the transpososome are protected by DNase I footprinting: the outermost A binding sites L1 and R1, as well as R2. Genetic evidence is also presented which corroborates this result. Efficient formation of Type 1 complexes occurs in mini-Mus with the L3 or R3 sites deleted or when the L2 site has been substituted; but no reaction occurs in the absence of R2. The protection at the L1 and R1 sites extends 12-13 bp beyond the Mu-host junctions as seen by DNase I and methidiumpropyl-EDTA.Fe(II) [MPE.Fe(II)] foot-printing, indicating Mu A contacts with the flanking host sequences in the transpososome but not on linear DNA; furthermore, hydroxyl radical footprinting shows an unprecedentedly large enhancement on the continuous strand, 2 bp beyond the nick site outside the Mu right end, which suggests that an altered DNA structure is induced upon Type 1 complex formation.

The growth hormone secretory response to fentanyl in rat: an involvement of μ type receptors

Fentanyl, a selective mu opioid receptor agonist, administered intravenously, influences growth hormone secretion in conscious male rats. A dose-response study demonstrated that the maximum growth hormone release was obtained with 10 micrograms/kg while higher doses were less or not effective. MR-2266 (6 mg/kg i.v.), a mu and kappa opioid receptor antagonist, and bremazocine (0.1 mg/kg i.v.) a mu opioid receptor antagonist with kappa agonistic properties, both potently inhibited the growth hormone response to fentanyl (10 micrograms/kg i.v.). In contrast, the effect of fentanyl on growth hormone release was not blocked in rats treated with either ICI-154129 (30 mg/kg i.v. or 150 micrograms/kg intracerebroventricularly a selective delta opioid receptor antagonist, or U-50488 (10 mg/kg i.v.), a specific kappa opioid receptor agonist. These results suggest that opioid receptors of the mu type are involved in the fentanyl-induced growth hormone release.

Complete structure and organization of immunoglobulin heavy chain constant region genes in a phylogenetically primitive vertebrate.

Immunoglobulin (Ig) gene organization in Heterodontus francisci (horned shark), a phylogenetically primitive vertebrate, is unique. Homologous Ig heavy chain variable (VH) and constant region (CH) specific probes were used to screen a spleen cDNA library constructed in lambda gt11. Both secretory (SEC) and transmembrane (TM) cDNA clones were recovered; the latter were identified by a negative selection strategy. The complete sequence of the CH portion of a Heterodontus genomic DNA-lambda clone also was determined. The sequences of the individual CH genes differ from each other in all exons. When compared to mammalian prototypes, similarities in exon and intron organization as well as conservation of sequences involved with differential splicing of SEC and TM mRNA indicate that Heterodontus heavy chain genes are of the mu type, although intron lengths are uniformly longer in Heterodontus. Heterodontus genes are not associated, however, with the family of DNA sequences that have been implicated in heavy chain class switching in mammals. Spleen cDNA library screening and RNA blot analyses indicate that mRNAs encoding TM Ig are exceedingly rare. The relationship between this quantitative difference and the distribution of polyadenylation signal sequences suggests that regulation of Ig gene expression in Heterodontus may be highly dependent on position effects.

Role of receptor regulation in opioid tolerance mechanisms.

The molecular basis of opioid tolerance/dependence has long eluded researchers, but recent advances in receptor regulation have suggested a useful conceptual approach to the problem. In NG108-15 neuroblastoma x glioma hybrid (NG) cells, opioid agonists inhibit adenylate cyclase in a dose-dependent, naloxone-antagonizable fashion. Chronic treatment with opioid agonists results in a series of molecular processes that, in a tolerance-like fashion, counteract this inhibition. These processes include desensitization and down-regulation of receptors and an increase in adenylate cyclase activity. Opioid inhibition of adenylate cyclase and opioid receptor down-regulation also have been observed in the brain. However, most studies have found that the receptors coupled to adenylate cyclase are not of the mu type, which are thought to be the primary mediators of opioid analgesia. Down-regulation has been observed for both mu and delta opioid receptors in the brain. However, in most cases, the time course of down-regulation is not correlated with that for tolerance development, and chronic morphine treatment does not result in down-regulation. Thus, opioid receptors in the brain, like those in NG cells, are subject to dynamic regulation by agonists, which probably has an important role in their function. However, it remains to be established that opioid receptor regulation is the basis of opioid tolerance and dependence.