Effect of circadian rhythm type on serum lipid levels in shift workers: A 5-year cohort study

We investigated how differences in circadian rhythm type affect the health of workers engaged in shift work. Employees, who were newly hired in a steel company between 2007 and 2011, received the Morningness–Eveningness Questionnaire (MEQ) survey. The target participants were 153 male shift workers who were not being treated with any antihyperlipidemic drugs and underwent periodic physical examinations including blood tests at least twice. According to the score of the MEQ at the time of joining the company, we classified the subjects into five types. Longitudinal changes in serum lipid level were estimated among the circadian rhythm types adjusted for age, BMI, and other covariates using a linear mixed model. The regression coefficient of total cholesterol level in the “definitely and moderately morning” group was ?17.83 (95% confidence interval (CI): ?33.42 to ?2.23), and in the “intermediate ‘group’ was ?16.84 [95% CI: ?30.40 to ?3.28], compared to the moderate evening type.” The total cholesterol level was higher in the moderately evening type than in any of the other groups. Between the Morningness–Eveningness (ME) type and Low-density lipoprotein (LDL) cholesterol levels, compared with the “moderately evening type” group, the regression coefficient in the “intermediate type” group was ?16.08 (95% CI: ?28.79 to ?3.37), and in the “definitely and moderately morning type” group was ?17.50 [95% CI: ?32.11 to ?2.88]. The “moderately evening type” group had a higher LDL cholesterol level than any of the other groups. Evening-type circadian rhythm type shift workers are more prone to elevated serum lipid levels.     

Glycosylation of human CRLR at Asn123 is required for ligand binding and signaling

Calcitonin receptor-like receptor (CRLR) constitutes either a CGRP receptor when complexed with receptor activity-modifying protein 1 (RAMP1) or an adrenomedullin receptor when complexed with RAMP2 or RAMP3. RAMP proteins modify the glycosylation status of CRLR and determine their receptor specificity; when treated with tunicamycin, a glycosylation inhibitor, CHO-K1 cells constitutively expressing both RAMP2 and CRLR lost the capacity to bind adrenomedullin. Similarly, in HEK293 EBNA cells constitutively expressing RAMP1/CRLR receptor complex CGRP binding was remarkably inhibited. Whichever RAMP protein was co-expressing with CRLR, the ligand binding was sensitive to tunicamycin. There are three putative Asn-linked glycosylation sites in the extracellular, amino terminal domain of CRLR at positions 66, 118 and 123. Analysis of CRLR mutants in which Gln was substituted for selected Asn residues showed that glycosylation of Asn123 is required for both the binding of adrenomedullin and the transduction of its signal. Substituting Asn66 or Asn118 had no effect. FACS analysis of cells expressing FLAG-tagged CRLRs showed that disrupting Asn-linked glycosylation severely affected the transport of the CRLR protein to the cell surface on N66/118/123Q mutant, and slightly reduced the level of the cell surface expression of N123Q mutant compared with wild-type CRLR. But other single mutants (N66Q, N118Q) had no effect for other single mutants. Our data shows that glycosylation of Asn66 and Asn118 is not essential for ligand binding, signal transduction and cell surface expression, and Asn123 is important for ligand binding and signal transduction rather than cell surface expression. It thus appears that glycosylation of Asn123 is required for CRLR to assume the appropriate conformation on the cell surface through its interaction with RAMPs.     

Polyamine cytotoxicity in the presence of bovine serum amine oxidase

The toxicity of extracellular spermine, determined in the presence of fetal calf serum, was studied using three cell lines: FM3A, L1210, and NIH3T3 cells. Amine oxidase in fetal calf serum produces aminodialdehyde generating acrolein spontaneously, H(2)O(2), and ammonia from spermine. Spermine toxicity was prevented by aldehyde dehydrogenase, but not by catalase. Similar concentrations of spermine and acrolein were needed to produce toxicity. Other aldehydes (formaldehyde, acetaldehyde, and propionaldehyde) and hydrogen peroxide were less toxic than acrolein. Spermidine and 3-aminopropanal, which produces acrolein, also exhibited severe cytotoxicity. The degree of cytotoxicity of spermine, spermidine, and 3-aminopropanal was nearly parallel with the amount of acrolein produced from each compound. Thus, it was deduced that acrolein is a major toxic compound produced from polyamines (spermine and spermidine) by amine oxidase.     

Genomic and Phylogenetic Analysis of the Human CD1 and HLA Class I Multicopy Genes

The human CD1 proteins belong to a lipid-glycolipid antigen-presenting gene family and are related in structure and function to the MHC class I molecules. Previous mapping and DNA hybridization studies have shown that five linked genes located within a cluster on human chromosome 1q22-23 encode the CD1 protein family. We have analyzed the complete genomic sequence of the human CD1 gene cluster and found that the five active genes are distributed over 175,600 nucleotides and separated by four expanded intervening genomic regions (IGRs) ranging in length between 20 and 68 kb. The IGRs are composed mostly of retroelements including five full-length L1 PA sequences and various pseudogenes. Some L1 sequences have acted as receptors for other subtypes or families of retroelements. Alu molecular clocks that have evolved during primate history are found distributed within the HLA class I duplicated segments (duplicons) but not within the duplicons of CD1. Phylogeny of the alpha3 domain of the class I-like superfamily of proteins shows that the CD1 cluster is well separated from HLA class I by a number of superfamily members including MIC (PERB11), HFE, Zn-alpha2-GP, FcRn, and MR1. Phylogenetically, the human CD1 sequences are interspersed by CD1 sequences from other mammalian species, whereas the human HLA class I sequences cluster together and are separated from the other mammalian sequences. Genomic and phylogenetic analyses support the view that the human CD1 gene copies were duplicated prior to the evolution of primates and the bulk of the HLA class I genes found in humans. In contrast to the HLA class I genomic structure, the human CD1 duplicons are smaller in size, they lack Alu clocks, and they are interrupted by IGRs at least 4 to 14 times longer than the CD1 genes themselves. The IGRs seem to have been created as "buffer zones" to protect the CD1 genes from disruption by transposable elements.     

Three-dimensional image analysis of the hepatic restructuring process in chronic active hepatitis

OBJECTIVE: To elucidate the process of hepatic restructuring in the course of chronic hepatitis from a morphologic viewpoint. STUDY DESIGN: The three-dimensional (3-D) liver structure was investigated by computer-aided reconstruction in five cases (one autopsy and four surgical cases) of chronic active hepatitis (type C), including early to late stages of restructuring. RESULTS: Our 3-D reconstruction revealed the following. At an early stage, portal and periportal inflammation and fibrosis widened the portal tracts, giving rise to the formation of portal-to-portal and portal-to-hepatic venous connections, although most central veins were still located at an almost normal site in the hepatic lobules. In a middle stage, bridging fibrosis developed to create a network of interstitium where the central veins were rather decreased in number, with regenerative nodules multiplying in the parenchyma. At the late stage, the lobular structure was destroyed, and the parenchyma consisted uniformly of regenerative nodules, with remaining but rearranged lobules among them. CONCLUSION: The above changes of liver structure suggest that in cirrhogenesis from chronic hepatitis, a combination of nodular regeneration and formation of an interstitial network come to replace the normal lobular structure, hastening the development of liver cirrhosis.     

Synthesis and characterization of intermediate and transition-state analogue inhibitors of gamma-glutamyl peptide ligases

The phosphonodifluoromethyl ketone and phosphonofluoridate derivatives of L-glutamic acid were synthesized and characterized as analogues of the gamma-glutamyl phosphate intermediate and the tetrahedral transition state, respectively, for the inhibition of gamma-glutamylcysteine synthetase and glutamine synthetase. The former served as a poor inhibitor of both enzymes, but the latter inhibited glutamine synthetase with a Ki of 59 microM and partially inactivated the enzyme in an NH3- and ATP-dependent manner.     

Cloning of a bovine orphan transporter and its short splicing variant

We have isolated a cDNA (bv7-3) encoding a member of the Na+,Cl(-)-dependent transporter family and its short splicing variant (bv7-3s) by screening a bovine retina cDNA library. Sequence analysis revealed that bv7-3 encodes a protein of 729 amino acids and is a bovine homologue of the rat orphan transporter v7-3-2. bv7-3s contains 265 amino acids, sharing 252 N-terminal amino acids with bv7-3. Both mRNAs for bv7-3 and bv7-3s were detected in nervous system by Northern blot analysis. In immunofluorescence analysis in transfected HEK 293T cells, myc-tagged bv7-3 was mainly detected on the plasma membrane, whereas myc-tagged bv7-3s showed a pattern of intracellular membrane staining.     

Genomic Organization Around the Centromeric End of the HLA Class I Region: Large-Scale Sequence Analysis

We previously sequenced two regions around the centromeric end of HLA class I and the boundary between class I and class III. In this paper we analyze the two regions of about 385 kb and confirm, giving a new line of evidence, that the following two pairs of the genomic segments were duplicated in evolution: (i) a 43-kb genomic segment including the HLA-B gene showing the highest polymorphism among the classical HLA class I loci (class Ia) and a 40-kb segment including the HLA-C locus showing the lowest polymorphism and (ii) a 52-kb segment including the MIC (MHC class I chain related gene) B and a 35-kb segment including MICA. We also found that repetitive elements such as SINEs, LINEs, and LTRs occupy as much as 47% of nucleotides in this 385-kb region. This unusually high content of repetitive elements indicates that repeat-mediated rearrangements have frequently occurred in the evolutionary history of the HLA class Ia region. Analysis of LINE compositions within the two pairs of duplicated segments revealed that (i) LINEs in these regions had been dispersed prior to both the duplication of the HLA-B and -C loci and the duplication of the MICB and MICA loci, and (ii) the divergence of the HLA-B and -C loci occurred prior to the duplication of the MICA and MICB loci. To find novel genes responsible for HLA class I-associated or other diseases, we performed computer analysis applying GenScan and GRAIL to GenBank's dbEST. As a result, at least five as yet uncharacterized genes were newly mapped on the HLA class I centromeric region studied. These novel genes should be analyzed further to determine their relationships to diseases associated with this region. Received: 16 June 1998 / Accepted: 18 August 1998     

QT interval and QT dispersion before and after diet therapy in patients with simple obesity

To evaluate whether a disordered QT interval and its dispersion in obese patients, if any, may be improved by therapeutic weight reduction, 36 obese patients admitted to our university hospital were examined over a 5-year period from April 1, 1992 to March 31, 1997. Participants included 18 males and 18 females whose mean age +/- SD was 28 +/- 9 and 33 +/- 14 years, respectively, and whose mean body mass index +/- SD was 35 +/- 5 and 38 +/- 6 kg/m2, respectively. Thirty-six control patients were matched in age and gender with the obese patients. All the obese patients were treated with behavioral therapy together with very-low-calorie conventional Japanese diet (VLCD: 370 kcal/day). A standard 12-lead electrocardiogram (ECG) revealed longer maximum (445 +/- 32 msec, mean +/- SD) and minimum (388 +/- 29 msec) heart rate corrected QT intervals (QTc intervals) in the obese group than in the control group (P < 0.0001 for each). QTc dispersion, defined as the difference between maximum and minimum QTc intervals derived from 12-lead ECG, was greater in the obese group (57 +/- 19 msec) than in the control group (32 +/- 13 msec) (P < 0.0001). Both the maximum and minimum QTc intervals in the obese patients were shortened, respectively, to 434 +/- 28 msec and 377 +/- 29 msec (P < 0.05 for each) with no significant change in either QTc dispersion, QRS voltage, or QRS duration following weight reduction. The coefficient value from the linear regression line between QT interval and RR interval in the obese group was less than in the control group. Together, the results show that obesity per se causes both a prolongation of QTc interval and an increase in QTc dispersion, and that weight reduction improves the prolonged QTc interval observed in obese patients.