The effect of bilirubin on biliary lipid secretion: Analysis by horseradish peroxidase associated intrahepatic vesicular transport system

The mechanism of biliary lipid secretion is still controverial and there is no definite information regarding how bilirubin inhibits biliary phospholipid and cholesterol secretions without affecting bile salt secretion. In this study, the effects of biliribin on intrahepatic vesicular transport and biliary lipid secretion were examined using bile-fistula rats. Horseradish peroxidase (HRP) was used as a tracer of intrahepatic vesicular transport. Bilirubin (5mg/100g BW) and/or HRP (5mg/100gBW) were injected through the mesenteric vein. Bile flow, biliary bile acid, biliary phospholipid and cholesterol outputs were examined in saline, HRP and HRP+bilirubin groups, respectively. Bile flow and biliary bile acid output were not affected by bilirubin administration. Biliary phospholipid and cholesterol as well as biliary HRP outputs were inhibited just after bilirubin administration, 42.8±6.1 SD% 47.7±5.1 SD%, and 33.4±3.8 SD%, respectively. These results suggested the participation of intrahepatic vesicular transport system in the inhibition of biliary lipid secretion by bilirubin and in its secretory mechanism. This study was partially funded by Uehara Life Science Foundation.     

Structural basis for solute transport,nucleotide regulation,and immunological recognition of Neisseria meningitidis PorB

PorB is the second most prevalent outer membrane protein in Neisseria meningitidis. PorB is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. Here, the x-ray crystal structure of PorB has been determined to 2.3 Å resolution. Structural analysis and cocrystallization studies identify three putative solute translocation pathways through the channel pore: One pathway transports anions nonselectively, one transports cations nonselectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and cocrystallization with the ATP analog AMP–PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a nonspecific electrostatic attraction.     

Clinical prediction rule to distinguish pelvic inflammatory disease from acute appendicitis in women of childbearing age

Objective

We aimed to develop a clinical prediction rule to distinguish pelvic inflammatory disease (PID) from acute appendicitis in women of childbearing age.

Methods

We reviewed medical records over a 4-year period of female patients of childbearing age who had presented with abdominal pain at an urban emergency department and had either appendicitis (n = 109) or PID (n = 72). A prediction rule was developed by use of recursive partitioning based on significant factors for the discrimination.

Results

The significant factors to favor PID over appendicitis were (1) no migration of pain (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.5-11.5), (2) bilateral abdominal tenderness (OR, 16.7; 95% CI, 5.3-50.0), and (3) absence of nausea and vomiting (OR, 8.4; 95% CI, 2.8-24.8). The prediction rule could rule out appendicitis from PID with sensitivity of 99% (95% CI, 94-100%) when classified as a low-risk group by the following factors: (1) no migration of pain, (2) bilateral abdominal tenderness, and (3) no nausea and vomiting.

Conclusion

We developed a prediction rule for childbearing-aged women presenting with acute abdominal pain to distinguish acute appendicitis from PID based on 3 simple, clinical features: migration of pain, bilateral abdominal tenderness, and nausea and vomiting. Prospective validation is needed in other settings.     

Type-specific evolution of amyloid plaque and angiopathy in APPsw mice

To clarify how Aβ deposits start in the brain, we examined the early to late stages of senile plaques and amyloid angiopathy in APPsw mice. All types of human senile plaques were observed in the mouse brains. The premature forms of cored plaques appeared first in the cerebral cortex of mice at 7–8 months old. Then, amyloid angiopathy emerged, followed by diffuse plaques consisting of Aβ1–42. Modifications of the N-terminus of Aβ were late phase phenomena. The premature forms of cored plaques were composed of central Aβ1–40 amyloid cores, surrounding amorphous Aβ1–42 deposits, and accumulation of Aβ1–42 in some peripheral cells. These cells were incorporated in amyloid cores, and these plaques developed to large cored plaques composed of Aβ1–40 and Aβ1–42. The size and number of cored plaques were increased with age. These findings indicate different evolution paths for cored plaques and diffuse plaques, and suggest the presence of a pathway that initiates with the intracellular accumulation of Aβ1–42 and leads to the development of classic plaques in human brain tissues.     

Identification of 16 novel mutations in the argininosuccinate synthetase gene and genotype-phenotype correlation in 38 classical citrullinemia patients

Classical citrullinemia (CTLN1), a rare autosomal recessive disorder, is caused by mutations of the argininosuccinate synthetase (ASS) gene, localized on chromosome 9q34.1. ASS functions as a rate-limiting enzyme in the urea cycle. Previously, we identified 32 mutations in the ASS gene of CTLN1 patients mainly in Japan and the United States, and to date 34 different mutations have been described in 50 families worldwide. In the present study, we report ASS mutations detected in 35 additional CTLN1 families from 11 countries. By analyzing the entire coding sequence and the intron-exon boundaries of the ASS gene using RT-PCR and/or genomic DNA-PCR, we have identified 16 novel mutations (two different 1-bp deletions, a 67-bp insertion, and 13 missense) and have detected 12 known mutations. Altogether, 50 different mutations (seven deletion, three splice site, one duplication, two nonsense, and 37 missense) in 85 CTLN1 families were identified. On the basis of primary sequence comparisons with the crystal structure of E. coli ASS protein, it may be concluded that any of the 37 missense mutations found at 30 different positions led to structural and functional impairments of the human ASS protein. It has been found that three mutations are particularly frequent: IVS6-2A>G in 23 families (Japan: 20 and Korea: three), G390R in 18 families (Turkey: six, U.S.: five, Spain: three, Israel: one, Austria: one, Canada: one, and Bolivia: one), and R304W in 10 families (Japan: nine and Turkey: one). Most mutations of the ASS gene are "private" and are distributed throughout the gene, except for exons 5 and 12-14. It seems that the clinical course of the patients with truncated mutations or the G390R mutation is early-onset/severe. The phenotype of the patients with certain missense mutations (G362V or W179R) is more late-onset/mild. Eight patients with R86H, A118T, R265H, or K310R mutations were adult/late-onset and four of them showed severe symptoms during pregnancy or postpartum. However, it is still difficult to prove the genotype-phenotype correlation, because many patients were compound heterozygotes (with two different mutations), lived in different environments at the time of diagnosis, and/or had several treatment regimes or various knowledge of the disease.     

Endothelium-dependent vasodilation in type II diabetes mellitus

Endothelial dysfunction is a major feature of atherosclerosis and it can also serve as an early atherosclerotic marker. Evaluation and assessment of the endothelial function is important to prevent serious atherosclerotic disease especially myocardial infarction, cerebrovascular disease and renal failure. To evaluate endothelial function we measured endothelium-dependent vasodilation (flow-mediated dilatation: %FMD) of the brachial artery with ultrasound. This method is non-invasive and can be repeatable in order to follow patients individually. Progressive atherosclerosis is often observed in diabetic patients who are not hypertensive. To evaluate the impairment of the endothelial function in type 2 diabetic patients, we examined %FMD in them and compared with hypertensive patients without diabetes and control subjects. We found that type 2 diabetic patients had the same endothelial dysfunction as hypertensive patients without diabetes. %FMD in both diabetic patients and hypertensive patients was lower than in control subjects. Moreover, %FMD of type 2 diabetic patients with hypertension was lower than %FMD of type 2 diabetic patients without hypertension. These finding suggests that endothelial dysfunction develops under the conditions of hypertension and hyperglycemia. Evaluating endothelial function with ultrasound is useful for assessment of atherosclerosis in diabetes.     

Blue rubber bleb nevus syndrome: Report of a patient with hemangiomas of the vaginal portion of the cervix appearing during pregnancy

Blue rubber bleb nevus syndrome (BRBNS) is a rare disorder showing venous malformations in the skin and gastrointestinal tract, and other internal organs. We encountered a patient with BRBNS in whom hemangiomas of the uterine cervix appeared during pregnancy. This was apparently the first reported occurrence. To avoid unexpected bleeding from hemangiomas, patients with BRBNS should be examined repeatedly for hemangiomas of the birth canal, and special care should be taken in deciding the mode of delivery.     

Polymorphic alleles of the human MEI1 gene are associated with human azoospermia by meiotic arrest

Genetic mechanisms are implicated as a cause of some male infertility, yet are poorly understood. Mouse meiotic mutant mei1 (meiosis defective 1) was isolated by a screening of infertile mice. Male mei1 mice have azoospermia due to meiotic arrest, and the mouse Mei1 gene is responsible for the mei1 phenotype. To investigate whether human MEI1 gene defects are associated with azoospermia by meiotic arrest, we isolated the human MEI1 cDNA based on the mouse Mei1 amino acid sequence. MEI1 is expressed specifically in the testis. Mutational analysis by direct sequencing of all MEI1 coding regions was performed in 27 men (13 European Americans, 13 Israeli and 1 Japanese) having azoospermia due to complete early meiotic arrest. This identified four novel, coding single-nucleotide-polymorphisms (cSNPs), i.e., SNP1 (T909G), SNP2 (A1582G), SNP3 (C1791A) and SNP4 (C2397T) in exons 4, 8, 9 and 14, respectively. Using these cSNPs, an association study was carried out between 26 non-Japanese patients with azoospermia and two sets of normal control men (61 normal European Americans and 60 Israelis). Consequently, SNP3 and SNP4 were shown to be associated with azoospermia among European Americans (P =0.0289 and P =0.0299 for genotype and allele frequencies at both the polymorphic sites, respectively), although no such association was observed among Israelis (P >0.05). Haplotype estimation revealed that the frequencies of SNP3–SNP4 (C–T), SNP3–SNP4 (A–C) and SNP3–SNP4 (A–T) were higher in the European American patients, and the frequency of SNP3–SNP4 (A–T) was also higher than in both control groups. These results suggest that MEI1 may play a role in meiosis during spermatogenesis, especially in European Americans.     

DICER and DROSHA gene expression and polymorphisms in autoimmune thyroid diseases

Dicer and Drosha are RNase III enzymes that are necessary for the biogenesis of most miRNAs. However, there are no reports on the association of Dicer and Drosha with the pathogenesis of autoimmune thyroid disease (AITD). We genotyped DICER rs3742330A/G and rs1057035T/C as well as DROSHA rs644236C/T and rs10719C/T polymorphisms in 255?Hashimoto's disease (HD) patients, in 255 Graves' disease (GD) patients and in 128 healthy controls by the polymerase chain reaction (PCR)- restriction fragment length polymorphism (RFLP) method. We also examined the expression of DICER and DROSHA gene in peripheral blood mononuclear cells (PBMCs) by quantitative RT-PCR (qRT-PCR) methods. The TT genotype of the DICER rs1057035 polymorphism was less frequent in GD patients (p?=?0.0098) than in healthy subjects. The CC genotype of DROSHA rs644236 polymorphism were more frequent in GD patients than in HD patients (p?=?0.0171). The gene expression of DICER was lower in patients with AITD compared with that in control subjects (p?=?0.0064) and was lower in patients with GD in remission than in patients with intractable GD (p?=?0.0213). In addition, the expression of DROSHA was lower in patients with AITD than that in control subjects (p?p?=?0.0440). In conclusion, the DICER rs1057035 TT genotype and DROSHA rs644236?CC genotype were associated with the development of GD and the differentiation between GD and HD, respectively. The expression levels of DICER and DROSHA genes were low in AITD and differed depending on the intractability of GD and the severity of HD, respectively.