A novel missense mutation (G2320R) in thyroglobulin causes hypothyroidism in rdw rats

The rdw rat is a hereditary hypothyroid variant initially derived from the Wistar-Imamichi strain. Proteome analysis by two-dimensional gelelectrophoresis showed that molecular chaperones accumulated in the thyroid glands, suggesting retention of abnormal proteins in the endoplasmic reticulum (ER). Anatomical studies indicated that thyroglobulin (Tg) was not secreted into the follicular lumina, but retained in the dilated ER. Sequencing of the entire Tg complementary DNA from the rdw rat revealed a missense mutation (G2320R) in the acetylcholinesterase-like domain at the 2320th amino acid residue. Carbohydrate residues of the G2320R Tg mutant were of the high-mannose ER type, as shown by sensitivity to the treatment with endoglycosidase H. Molecular chaperones, GRP94, GRP78, and calreticulin, were all accumulated in the rdw rat thyroid glands. Computer analysis of protein secondary structure predicted that the mutation would cause extension of the helix where beta-sheet and turns were formed in the normal Tg. Altered folding of Tg might account for the impaired intracellular transport of Tg and activated premature degradation by the same mechanism as in ER storage diseases.     

The risk of adolescent suicide across patterns of drug use: a nationally representative study of high school students in the United States from 1999 to 2009

Objective

Substance use is associated with suicidal ideation, planning and attempts among adolescents, but it is unclear how this association varies across different types and number of substances. This study examined the association between patterns of substance use and suicidality among a nationally representative sample of high school students in the United States during the last decade.

Method

Data from the 2001 to 2009 Youth Risk Behavior Survey including 73,183 high school students were analyzed. Logistic regression analyses examined the association between lifetime use of ten common substances of abuse (alcohol, cocaine, ecstasy, hallucinogens, heroin, inhalants, marijuana, methamphetamines, steroids, and tobacco) and four measures of suicidality over the last year (suicidal ideation, suicide plan, suicide attempt, and severe suicide attempt requiring medical attention), controlling for potential confounders (socio-demographic variables, interpersonal violence, sexual intercourse, and symptoms of depression and eating disorder).

Results

Among the ten substances, univariate analysis demonstrates that adolescents reporting a history of heroin use have the strongest association with suicidal ideation, suicide plan, suicide attempts and severe suicide attempts in the last year (odds ratio = 5.0, 5.9, 12.0, and 23.6 compared to non-users), followed by users of methamphetamines (OR = 4.3–13.1) and steroids (OR = 3.7–11.8). Cocaine, ecstasy, hallucinogens and inhalants had a moderate association with suicidality (OR = 3.1–10.8). Users of marijuana, alcohol and tobacco also had an increased odds ratio of suicidality (OR = 1.9–5.2). The association between each of ten substances and the four measures of suicidality remained significant with multivariate analysis controlling for multiple confounders (p < 0.05), except for the association between alcohol use and severe suicide attempts. The seven illicit substances had a stronger association with severe suicide attempts as compared to all other confounding risk factors except depression. The number of substances used had a graded relationship to suicidality.

Conclusions

Substance abuse is a strong risk factor for suicidal thoughts and behaviors among American high school students, with the strength of this relationship dramatically increasing with particular illicit drugs and a higher number of substances. The findings reinforce the importance of routine screening for substance abuse in the assessment of adolescent suicide risk.     

Morgagni hernia diagnosed by MRI

We herein present a patient with Morgagni hernia which was diagnosed by magnetic resonance imaging (MRI). The patient had a progressively enlarging mass in the right cardiophrenic angle on chest roentgenogram. On computed tomography (CT) scans, the mass was revealed to have fat density and therefore was suspected to be either a lipoma or liposarcoma. MRI clearly demonstrated that the mass shadow was composed of omental fat herniating into the right thorax through the diaphragmatic hiatus. MRI is thus considered to be a useful noninvasive modality for the evaluation of lower anterior mediastinal masses demonstrating fat density on CT.     

Blockade by the local anaesthetic, tetracaine, of desensitization of Ca-induced Ca release after muscarinic stimulation in smooth muscle.

1. Desensitization of contractile responses dependent on release of intracellularly stored Ca elicited by carbachol, histamine or caffeine was measured after desensitizing treatment with carbachol or histamine in the presence or absence of local anaesthetics in Ca-free solution containing 2 mM EGTA in the smooth muscle of guinea-pig taenia caecum. 2. Histamine-induced homologous desensitization was inhibited by tetracaine and procainamide. Dibucaine did not exert an inhibitory effect on the desensitization. This is consistent with our previous findings concerning the effects of local anaesthetics on the desensitization of histamine H1-receptors measured under normal physiological conditions. 3. Carbachol induced a functional change of intracellular Ca stores which resulted in heterologous desensitization. Tetracaine completely blocked carbachol-induced desensitization of the caffeine-elicited contraction, but in the case of carbachol-induced desensitization of carbachol- and histamine-elicited contractions, this blocking effect of tetracaine was very weak and absent, respectively. The other local anaesthetics used did not affect the desensitization. These results suggest that the Ca-induced and inositol trisphosphate-induced Ca release mechanisms were both desensitized by carbachol and that the desensitization of the Ca-induced Ca release mechanism was selectively blocked by tetracaine.     

Regulation of TH activity by GAD immunoreactivity in rat peri-LC after chronic variable stress]

Locus coeruleus (LC) is the major component of noradrenergic neurons in the brain. The corticotropin-releasing hormone (CRH) and norepinephrine (NE) are suggested to play a role in modulating the central stress response. In a previous study we observed a decrease of the basal level of tyrosine hydroxylase (TH) immunoreactivity (-ir) in the LC of rats treated with chronic variable stress (CVS) for 14 days. Furthermore a novel stressor produced an enhanced response of the TH-ir after CVS. In the present study we examined the effect of CVS on the glutamic acid decarboxylase (GAD)-ir activity of periaqueductal gray (PAG), prepositus hypoglossi (PrH) and peri-LC. The GAD-ir was significantly increased in PrH and peri-LC after CVS. The footshock-induced reactivity in the GAD-ir was decreased in both regions after CVS. Moreover, we investigated the influence of the CRH receptor antagonist, alphah-CRH (i.c.v.) on the CVS-induced activation of the TH-ir in the LC. The alphah-CRH i.c.v. diminished the enhanced-TH reactivity by novel stressor after CVS. Our results suggest that the GABA activity in peri-LC and PrH might regulate the LC-TH response, and also the CRH input from central nucleus of amygdala (CeA) and/or the bed nucleus of stria terminalis (BNST) might regulate the TH reactivity.     

Terminal segment of Kluyveromyces lactis linear DNA plasmid pGKL2 supports autonomou sreplication of hybrid plasmids in Saccharomyces cerevisiae

Summary By use of linear DNA plasmid pGKL2 from the yeast Kluyveromyces lactis we have constructed hybrid plasmids carrying a LEU2 gene of Saccharomyces cerevisiae as a selectable marker. The replication properties of hybrid plasmids in yeasts were investigated. We demonstrated that the insertion of a LEU2 gene into pGKL2 resulted in circularization of the hybrid plasmids and pGKL2 segment supported autonomous replication of the plasmids. Moreover, the hybrid plasmids propagated autonomously, independently of the presence of the natural pGKL2 plasmid.     

Intact cell binding for in vitro prediction of sedative and non-sedative histamine H1-receptor antagonists based on receptor internalization

We evaluated changes in the binding properties of sedative and non-sedative histamine H1-receptor antagonists induced by internalization of H1 receptors in intact human U373 MG astrocytoma cells. Internalization of H1 receptors was induced without their degradation by treatment with 0.1 mM histamine for 30 min at 37 degrees C, and then the intact cell binding assay was performed at 4 degrees C. The binding properties of [3H]mepyramine, a cell-penetrating radioligand for H1 receptors, were not changed by histamine pretreatment. Displacement curves for sedative H1-receptor antagonists (diphenhydramine, chlorpheniramine, promethazine, ketotifen, azelastine and oxatomide) against [3H]mepyramine binding were not changed by histamine pretreatment. In contrast, the displacement curves for non-sedative H1-receptor antagonists (mequitazine, bepotastine, olopatadine, epinastine, carebastine, desloratadine and fexofenadine) were changed by histamine pretreatment: two types of changes, i.e. a rightward shift in the monophasic curve or an increase in the proportion of the low affinity component of the biphasic curve, were prevented under hypertonic conditions, in which clathrin-mediated receptor internalization is known to be inhibited. Thus, internalization-mediated changes in the binding properties of H1-receptor antagonists were well correlated with their sedative and non-sedative behaviors, which might confirm their permeability through the biomembrane and possibly the blood brain barrier.     

Wasabi-Derived 6-(Methylsulfinyl)Hexyl Isothiocyanate Induces Apoptosis in Human Breast Cancer by Possible Involvement of the NF-κB Pathways

6-(methylsulfinyl)hexyl isothiocyanate (6-MSITC) is a bioactive ingredient of wasabi (Wasabia japonica), which is a popular spice in Japan. 6-MSITC has been reported to inhibit the proliferation of breast cancer and melanoma cell lines. We inoculated 30 female Balb-nu/nu mice with MDA-MB-231 or -453 cells, and orally administered varying concentrations of 6-MSITC for 12 days following tumor growth. The tumor volumes and tumor weights from mice inoculated with MDA-MB-231 cells, and the tumor volumes of MDA-MB-453 cells were significantly inhibited by 6-MSITC on Days 9 and 11 after drug administration. DNA fragmentation, DNA ladder, and caspase 3/7 activity performed in vitro revealed that 6-MSITC induced apoptosis of MDA-MB-231, MDA-MB-453, and MCF-7 cells. Furthermore, nuclear factor-κB (NF-κB) expression in the nuclei and phosphorylation of inhibitor κBα (IκBα) was downregulated by 6-MSITC in a concentration-dependent manner; however, this activity was not observed in MCF-7 cells. Moreover, this downregulation of phosphorylated IκBα by 6-MSITC in MDA-MB-231 and -453 cells supports its inhibitory effects on NF-κB activity. The expression of phosphorylated AKT (pAKT) reduced by 6-MSITC was confirmed in MDA-MB-231 cells. Thus, we conclude that 6-MITC promotes apoptosis of breast cancer cells by inhibiting NF-kB and therefore releasing its control of the PI3K/AKT pathway.