Characterization of naturally occurring protease inhibitor-resistance mutations in genotype 1b hepatitis C virus patients

Background and aims

Protease inhibitor (PI)-resistant hepatitis C virus (HCV) variants may be present in substantial numbers in PI-untreated patients according to recent reports. However, influence of these viruses in the clinical course of chronic hepatitis C has not been well characterized.

Methods

The dominant HCV nonstructural 3 (NS3) amino acid sequences were determined in 261 HCV genotype 1b-infected Japanese patients before pegylated interferon plus ribavirin (PEG-IFN/RBV) therapy, and investigated the patients?? clinical characteristics as well as treatment responses including sustained virological response (SVR) rate. HCV-NS3 sequences were also determined in 39 non-SVR patients after completion of the therapy.

Results

Four single mutations (T54S, Q80K, I153V, and D168E) known to confer PI resistance were found in 35 of 261 patients (13.4%), and double mutations (I153V plus T54S/D168E) were found in 6 patients (2.3%). Responses to PEG-IFN/RBV therapy did not differ between patients with and without PI-resistance mutations (mutation group, SVR 48%; wild-type group, SVR 40%; P?=?0.38). On the other hand, two mutations appeared in two non-SVR patients after PEG-IFN/RBV therapy (I153V and E168D, 5.1%).

Conclusions

PI-resistance-associated NS3 mutations exist in a substantial proportion of untreated HCV-1b-infected patients. The impact of these mutations in the treatment of PIs is unclear, but clinicians should pay attention to avoid further development of PI resistance.     

Synergistic Effect by Co‐Administration of Tamsulosin and Solifenacin on Bladder Activity in Rats

Objectives: We examined the effects of alpha1‐adrenoceptor antagonist (tamsulosin hydrochloride) and antimuscarinic agent (solifenacin succinate) alone or in combination on the urinary adenosine triphosphate (ATP) level and cystometric parameters before and after bladder stimulation. Methods: Female rats were administered tamsulosin hydrochloride (0.5 or 3 µg/kg/h) and/or solifenacin succinate (20 or 100 µg/kg/h) via a subcutaneously implanted osmotic minipump. Rats receiving distilled water were used as control. After 2 weeks, continuous cystometry with physiological saline or 0.1% acetic acid solution was performed. Urinary ATP level was also measured before and after stimulation by 0.1% acetic acid solution. Results: During cystometry with bladder stimulation, the interval between voiding became shorter and the maximum voiding pressure (MVP) became higher in the control group. In the high‐dose tamsulosin and solifenacin groups, the inhibition of urinary frequency was observed. The MVP also became higher in the high‐dose tamsulosin group, but such a change was not seen in the high‐dose solifenacin group. In case of low‐dose administration, either agent alone did not inhibit the increase of urinary frequency and MVP due to bladder stimulation. However, co‐administration of these ineffective low doses of tamsulosin and solifenacin resulted in the inhibition of urinary frequency. The high‐dose or low‐dose solifenacin group and the co‐administration group showed similar inhibition of the increase of urinary ATP after bladder stimulation. Conclusion: Tamsulosin may have a different effect on the bladder and/or the neuronal pathways that is unrelated to ATP, so the combination of tamsulosin and solifenacin may synergistically inhibit urinary frequency after bladder stimulation.     

High levels of stearic acid,palmitoleic acid,and dihomo-γ-linolenic acid and low levels of linoleic acid in serum cholesterol ester are associated with high insulin resistance

The association of fatty acid composition with insulin resistance and type 2 diabetes has been reported in Western populations, but there is limited evidence of this association among the Japanese, whose populace consume large amounts of fish. To test the hypothesis that high palmitic, palmitoleic, and dihomo-γ-linolenic acids and low levels of linoleic and n-3 fatty acids are associated with higher insulin resistance among the Japanese, the authors investigated the relationship between serum fatty acid composition and serum C-peptide concentrations in 437 Japanese employees aged 21 to 67 years who participated in a workplace health examination. Serum cholesterol ester and phospholipid fatty acid compositions were measured by gas-liquid chromatography. Desaturase activity was estimated by fatty acid product-to-precursor ratios. A multiple regression was used to assess the association between fatty acid and C-peptide concentrations. C-peptide concentrations were associated inversely with linoleic acid levels in cholesterol ester and phospholipid (P for trend = .01 and .02, respectively) and positively with stearic and palmitoleic acids in cholesterol ester (P for trend =.02 and .006, respectively) and dihomo-γ-linolenic acid in cholesterol ester and phospholipid (P for trend < .0001 for both). C-peptide concentrations were not associated with n-3 polyunsaturated fatty acids. C-peptide concentrations significantly increased as δ-9-desaturase (16:1 n-7/16:0) and δ-6-desaturase (18:3 n-6/18:2 n-6) increased (P for trend = .01 and .03, respectively) and δ-5-desaturase (20:4 n-6/20:3 n-6) decreased (P for trend = .004). In conclusion, a fatty acid pattern with high levels of serum stearic, palmitoleic, or dihomo-γ-linolenic acids; δ-9-desaturase (16:1 n-7/16:0) or δ-6-desaturase (18:3 n-6/18:2 n-6) activities; and low levels of serum linoleic acid or δ-5-desaturase (20:4 n-6/20:3 n-6) activity might be associated with higher insulin resistance in Japanese adults.     

Genetic polymorphisms of XRCC1, alcohol consumption, and the risk of colorectal cancer in Japan

Background

X-ray cross-complementing group 1 (XRCC1) polymorphisms affect DNA repair capacity and may therefore be of importance in colorectal carcinogenesis. Alcohol consumption, an important risk factor for colorectal cancer, may induce carcinogenesis through DNA damage caused by the toxic effects of alcohol or its metabolites. Therefore, we examined the associations of XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms with colorectal cancer and the impact of the association between alcohol consumption and colorectal cancer risk.

Methods

This case-control study in Fukuoka, Japan including 685 cases and 778 controls. The cases were incident patients with histologically confirmed colorectal adenocarcinoma. The controls were randomly selected community subjects.

Results

The XRCC1 399Gln/Gln genotype was significantly associated with colorectal cancer risk (adjusted odds ratio [OR] 1.57, 95% CI 1.01–2.42; relative to 399Arg/Arg genotype). The association was strongest in individuals with high alcohol consumption. The Arg280His polymorphism modified the association between alcohol consumption and colorectal cancer risk (interaction P = 0.049). The OR of colorectal cancer in individuals with the 280His allele was 0.45 (95% CI 0.26–0.78) as compared with the 280Arg/Arg genotype limited to the 399Gln allele (interaction P = 0.001). The adjusted ORs for 399Gln/Gln-280Arg/Arg-194Arg/Arg and 399Arg/Gln-280Arg/Arg-194Arg/Trp were 1.71 (95% CI 1.02–2.87) and 1.57 (95% CI 1.05–2.33), respectively, with 399Arg/Arg-280Arg/Arg-194Arg/Arg as reference (interaction P = 0.418).

Conclusions

The findings are additional evidence that individuals with the XRCC1 399Gln/Gln genotype have an increased risk of colorectal cancer, and that XRCC1 polymorphisms have an important role in colorectal cancer risk associated with alcohol consumption or gene-gene interaction.Key words: XRCC1 polymorphisms, alcohol consumption, colorectal cancer     

Gastrointestinal function and quality of life after pylorus-preserving pancreatoduodenectomy

The pylorus-preserving pancreatoduodenectomy (PPPD) has taken the place of the conventional Whipple pancreato-duodenectomy as the standard procedure for various periampullary disease. With recent advances in surgical techniques and improvements in perioperative management, the number of long-term survivors after PPPD is increasing. As a result, surgeons should pay more attention to the patients' postoperative gastrointestinal function, nutrition, and quality of life (QOL). Gastric stasis, which is a frequent complication during the early postoperative period after PPPD, prolongs the hospital stay and impairs the QOL in the intermediate term. Several possible pathogeneses for this gastric stasis have been postulated; however, the precise mechanism remains unclear. The gastric emptying function gradually recovers to the preoperative level by 6 months after PPPD. Pancreatic functions are likely to be maintained for at least 1 year after PPPD; however, in some cases, they tend to gradually deteriorate over time after the operation, depending on the type of pancreatic reconstruction or the preoperative condition of the pancreas. It is important to note that preoperative and postoperative pancreatic exocrine function strongly influence the postoperative outcome regarding such factors as pancreatic fistula, body weight maintenance, nutrition, and the QOL. The QOL, as assessed by questionnaire, normally returns to the preoperative level within 6 months after PPPD, and this correlates with the changes in gastrointestinal function and nutritional status. It still remains an unresolved question, however, whether the Billroth-I PPPD really leads to better long-term nutritional status, but worse early gastric emptying function, than the Billroth-II type of reconstruction.     

Nuclear Factor κB Activation and Antiapoptosis in Mucosa-Associated Lymphoid Tissue Lymphoma

Three distinct chromosomal translocations, t(11;18), t(1;14), and t(14;18), involving the API2-MALT1 fusion protein, BCL10, and MALT1 have been convincingly implicated in the pathogenesis of mucosa-associated lymphoid tissue (MALT) lymphomas. Recent genetic and biochemical studies have indicated that BCL10 and MALT1 form a physical and functional complex and are both essential for nuclear factor kappaB (NF-kappaB) activation by antigen receptor stimulation in lymphocytes. API2-MALT1 can bypass the BCL10/MALT1 pathway linking to NF-kappaB activation, thereby inducing antigen receptor-independent events of lymphocytes. BCL10/MALT1- and API2-MALT1-induced NF-kappaB activation can be assumed to be able to contribute to antiapoptosis, probably through NF-kappaB-mediated up-regulation of several apoptotic inhibitor genes. We also have provided direct evidence that API2-MALT1 can exert an antiapoptotic effect, in part through its direct interaction with apoptotic regulators. We therefore hypothesize that the antiapoptotic effect of API2-MALT1 may be mediated by the interaction with apoptotic regulators as well as by the up-regulation of apoptotic inhibitor genes. Finally, we hope that further studies will stimulate research leading to the development of therapeutic drugs that specifically inhibit the antigen receptor-stimulated NF-kappaB activation pathway. Such drugs should be useful for interfering with inappropriate proliferation of lymphocytes associated with inflammatory and neoplastic disorders, including MALT lymphomas.     

Paroxysmal nocturnal haemoglobinuria with coexisting deficiency of the ninth component of complement: lack of massive haemolytic attack

A 47-year-old woman with paroxysmal nocturnal haemoglobinuria (PNH) was found to have an inherited deficiency in the ninth complement component (C9). In complement-sensitivity lysis tests, 80% of her erythrocytes were markedly complement-sensitive (PNH-III). Laser cytofluorimetry with a monoclonal antibody against decay-accelerating factor (DAF) revealed that 95% of her erythrocytes were DAF-negative. Surprisingly, she has suffered only mild haemolysis and has never experienced massive spontaneous haemolysis. Gross haemoglobinuria and jaundice occurred only after receiving postoperative transfusion of whole blood. In her serum, C9 was not detectable either by immunological or by functional assays. Both the Ham test and the sugar water test using normal human serum or plasma yielded marked haemolysis of the patient's erythrocytes. When the patient's serum or plasma was used, only a trace of lysis was detected. Addition of purified human C9 to her plasma fully restored haemolysis. These observations indicated that C9 may play a critical role in haemolytic attacks in patients with PNH and that characteristic haemolysis in PNH may be tempered by coexisting C9 deficiency.     

Paroxysmal nocturnal haemoglobinuria clones in patients with myelodysplastic syndromes

Among acquired stem cell disorders, pathological links between myelodysplastic syndromes (MDS) and aplastic anaemia (AA), and paroxysmal nocturnal haemoglobinuria (PNH) and AA, have been often described, whereas the relationship between MDS and PNH is still unclear. We analysed blood cells of patients with MDS to determine the incidence of the PNH clone, and analysed the PIG-A gene to find mutations characteristic of the PNH clone in MDS. In four (10%) of 40 patients with MDS, flow cytometry showed affected erythrocytes and granulocytes negative for decay-accelerating factor (DAF) and CD59. The population of affected erythrocytes was smaller in MDS patients with PNH clone (MDS/PNH) than in patients with de novo PNH, and haemolysis was milder in the MDS/PNH patients. PIG-A mutations were found in granulocytes of all patients with MDS/PNH. In type and site, the PIG-A mutations were heterogenous, similar to that observed in de novo PNH; i.e. no mutation specific to MDS/PNH was identified. Of note, three of four patients with MDS/PNH each had two PNH clones with different PIG-A mutations, suggesting that PIG-A is mutable in patients with MDS/PNH. In a MDS/PNH patient with trisomy 8, FISH detected a distinct karyotype in a portion of granulocytes with PNH phenotype, indicating that PNH and MDS partly shared affected cells. Thus, MDS predisposes to PNH by creating conditions favourable to the genesis of PNH clone. Considering the increasing prevalence and incidence of MDS, these disorders could be useful for investigating the mechanism by which PIG-A mutation is induced.     

Marked increase of serum hepatitis C virus (HCV) RNA titer during treatment with high-dose prednisolone in a case of polymyositis

A 70-year-old Japanese woman with hepatitis C virus (HCV) infection was diagnosed with polymyositis and treated with high-dose prednisolone (PSL). The serum alanine aminotransferase (ALT) level increased from 78 to 345 U/l 1 week after initiating treatment, although the polymyositis settled promptly. Furthermore, the serum HCV RNA level increased markedly from 110 to 850 kIU/ml 3 weeks after starting treatment. Previously, the patient had suffered an occlusion of the left branch of the retinal vein secondary to hyperviscosity syndrome resulting from Sjögrens syndrome and low-dose PSL treatment had been commenced. The serum HCV RNA and transaminase levels had not increased during this low-dose PSL treatment. Although intensive immunosuppression is necessary as an initial treatment of several collagen diseases including polymyositis, high-dose PSL therapy may markedly augment the serum HCV RNA level and therefore careful observation is necessary in HCV-infected patients.     

Effect of continuous arterial infusion of protease inhibitor on experimental acute pancreatitis

Journal of Gastroenterology -