Based on variation in nucleotide sequence within restricted regions in the putative C (core) gene of hepatitis C virus (HCV), four groups of HCV have been postulated in a panel of 44 HCV isolates. They were provisionally designated types I, II, III and IV. A method for typing HCV was developed, depending on the amplification of a C gene sequence by polymerase chain reaction using a universal primer (sense) and a mixture of four type-specific primers (antisense). HCV types were determined by the size of the products specific to each of them. Type II was found in HCV samples from 131 (82%) of 159 blood donors, more often than in those from 48 (60%) of 80 patients with non-A, non-B (NANB) liver disease in Japan (P< 0-01). In 11 haemophiliacs who had received imported coagulation factor concentrates, type I was found in five, as against type II in four. Double infection with two different HCV types was found in two patients with chronic NANB liver disease (types I and II; II and III) and two haemophiliacs (types I and II; I and III). HCV types were identical in mother and baby in each of two examples of perinatal transmission, and were also identical in donor and recipient in a case of accidental needle exposure.

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The complete nucleotide sequence of a hepatitis C virus derived from plasma of a human carrier in Japan was determined. The cDNA of the isolate (HC-J6) contained 9481 nucleotides and an additional T stretch of 30 to 108 nucleotides at the 3' end, and had one large open reading frame coding for a polyprotein of 3033 amino acids. It differed by 31.8 to 32.1% in the nucleotide sequence and by 27-4 to 27-7 % in the amino acid sequence from an American isolate and two Japanese isolates previously reported. Among these four isolates, the 5' non-coding region of 329 to 341 nucleotides was well conserved (>93% identity), whereas the 3' non-coding region of 39 to 45 nucleotides (T stretches not included) was more variable (>30% identity). An excellent degree of conservation of the 5' non-coding region would reflect its pivotal role in replication, and primers deduced from this region could be applied for the sensitive and specific detection of viral RNA by polymerase chain reaction. Due to a high degree of similarity in the amino acid sequence of the putative core protein (>90%), antigen probes deduced from it would be suitable for the serological diagnosis of HCV infection. Low sequence similarity in the putative envelope protein (> 53 % identity), however, would have to be taken into account in considering the immunoprophylaxis of HCV infection.

Nesfatin-1 is a novel satiety molecule in the hypothalamus and is also present in peripheral tissues. Here we sought to identify the active segment of nesfatin-1 and to determine the mechanisms of its action after peripheral administration in mice. Intraperitoneal injection of nesfatin-1 suppressed food intake in a dose-dependent manner. Nesfatin-1 has three distinct segments; we tested the effect of each segment on food intake. Injection of the midsegment decreased food intake under leptin-resistant conditions such as db/db mice and mice fed a high-fat diet. After injection of the midsegment, expression of c-Fos was significantly activated in the brainstem nucleus tractus solitarius (NTS) but not in the hypothalamic arcuate nucleus; the nicotinic cholinergic pathway to the NTS contributed to midsegment-induced anorexia. Midsegment injection significantly increased expression of proopiomelanocortin and cocaine- and amphetamine-regulated transcript genes in the NTS but not in the arcuate nucleus. Investigation of mutant midsegments demonstrated that a region with amino acid sequence similarity to the active site of agouti-related peptide was indispensable for anorexigenic induction. Our findings indicate that the midsegment of nesfatin-1 causes anorexia, possibly by activating POMC and CART neurons in the NTS via a leptin-independent mechanism after peripheral stimulation.

The outcome of acute hepatitis B virus (HBV) infection is variable, influenced by host and viral factors. From 1982 through 2004, 301 patients with acute HBV infection entered a multi-center cross-sectional study in Japan. Patients with fulminant hepatitis (n ‫؍‬ 40) were older (44.7 ؎ 16.3 vs. 36.0 ؎ 14.3 years, P < .0017), less predominantly male (43% vs. 71%, P ‫؍‬ .0005), less positive for hepatitis B e antigen (HBeAg) (23% vs. 60%, P < .0001), less infected with subgenotype Ae (0% vs. 13%, P < .05), and more frequently with Bj (30% vs. 4%, P < .0001) than those with acute self-limited hepatitis (n ‫؍‬ 261). Precore (G1896A) and core-promoter (A1762T/G1764A) mutations were more frequent in patients with fulminant than acute self-limited hepatitis (53% vs. 9% and 50% vs. 17%, P < .0001 for both). HBV infection persisted in only three (1%) patients, and they represented 2 of the 23 infected with Ae and 1 of the 187 with the other subgenotypes (9% vs. 0.5%, P ‫؍‬ .032); none of them received antiviral therapy. In multivariate analysis, age 34 years or older, Bj, HBeAg-negative, total bilirubin 10.0 mg/dL or greater, and G1896A mutation were independently associated with the fulminant outcome. In in vitro transfection experiments, the replication of Bj clone was markedly enhanced by introducing either G1896A or A1762T/G1764A mutation. In conclusion, persistence of HBV was rare (1%) and associated with Ae, whereas fulminant hepatitis was frequent (13%) and associated with Bj and lack of HBeAg as well as high replication due to precore mutation in patients with acute HBV infection.