Extensive mutagenesis of the hepatitis B virus core gene and mapping of mutations that allow capsid formation

We generated a large number of mutations in the hepatitis B virus (HBV) core gene inserted into a bacterial expression vector. The new mutagenesis procedure generated deletions and insertions (as sequence repeats) of various lengths at random positions between M1 and E145 but not substitutions. The R-rich 30-amino-acid C-terminal domain was not analyzed. A total of 50,000 colonies were tested with a polyclonal human serum for the expression of hepatitis B core or e antigen. A total of 110 mutants randomly chosen from 1,500 positive colonies were genotyped. Deletions and insertions were clustered in four regions: D2 to E14, corresponding to the N-terminal loop in a model for the core protein fold (B. Bottcher, S. A. Wynne, and R. A. Crowther, Nature 386:88-91, 1997); V27 to P50 (second loop); L60 to V86 (upper half of the alpha helix forming the N-terminal part of the spike and the tip of the spike); and V124 to L140 (C-terminal part of the C-terminal helix and downstream loop). Deletions or insertions in the remaining parts of the molecule forming the compact center of the fold seemed to destabilize the protein. Of the 110 mutations, 38 allowed capsid formation in Escherichia coli. They mapped exclusively to nonhelical regions of the proposed fold. The mutations form a basis for subsequent analysis of further functions of the HBV core protein in the viral life cycle.     

Nosocomial hepatitis B virus, hepatitis C virus and HIV infections by infectious medial personnel

Radicular dentin dysplasia (DD-I) is a rare hereditary dental alteration. It is characterized clinically by almost normal looking crowns and severe hypermobility of the teeth. The radiographic analysis, on the other hand, discloses the obliteration of all pulp chambers, the short, malformed roots and plenty of periapical bone radiolucencies on noncarious teeth. A case of radicular dentin dysplasia is presented. In this 43-year-old woman the diagnosis was supported, besides the clinical and radiographic analysis, by the pedigree of the proband, which showed the autosomal dominant pattern of feature transmission. Further-more, the electron microscopic analysis of one extracted molar revealed the atubular structure of the secondary dentin, and its globular organization.     

Hepatitis B virus infection, hepatitis B vaccine, and hepatitis B immune globulin

Hepatitis B virus (HBV) infection is a major health problem in the United States; in 1995, approximately 128,000 cases occurred. Transmission of HBV occurs primarily by blood exchange (eg, by shared needles during injection drug use) and by sexual contact. Persons infected early in life are much more likely to become chronically infected than those infected during adulthood: as many as 90% of infants infected perinatally develop chronic infection and up to 25% will die of HBV-related chronic liver disease as adults. Clinical signs of acute hepatitis occur in about 50% of infected adults but in only 5% of infected preschool-aged children. In the United States, hepatitis B vaccine is currently made by recombinant DNA technology using baker's yeast. Preexposure vaccination results in protective antibody levels in almost all infants and children (> 95%) and healthy adults younger than 40 years of age (> 90%). The most common adverse event following administration of hepatitis B vaccine is pain at the injection site, which occurs in 13% to 29% of adult and 3% to 9% of children. A comprehensive hepatitis B vaccination policy is now recommended that includes (1) routine infant vaccination; (2) catch-up vaccination of 11- to 12-year-olds who were not previously vaccinated; (3) catch-up vaccination of young children at high risk for infection; (4) vaccination of adolescents and adults based on lifestyle or environmental, medical, and occupational situations that place them at risk; and (5) prevention of perinatal HBV infection.     

Effect of mutations in the small envelope protein of hepatitis B virus on assembly and secretion of hepatitis delta virus

The gene coding for the small (S) envelope protein of hepatitis B virus was mutated to identify sequences important for the envelopment of the nucleocapsid during morphogenesis of hepatitis delta virus (HDV) virions. This study was focused on a domain of the S protein that is exposed in the cytoplasm during synthesis and thereby represented a good candidate for interaction with the viral nucleocapsid during virion assembly. The mutations consisted of deletion/insertions spanning the entire cytosolic domain of S between amino acid residues 24 and 80. Although the expression of mutants clustered between residues 59 and 80 could not be obtained, we demonstrated that a large part of the cytosolic loop, from residues 29-47 and 49-59, does not contain motifs essential for production of hepatitis B virus subviral particles or HDV virions. However, deletion of residues 24-28 led to the synthesis of S protein mutant, which was competent for secretion of subviral particles but deficient for production of HDV. We concluded that the sequence between Arg-24 and Ile-28 located at the carboxyl boundary of the transmembrane signal I for S contains residue or residues important for HDV particle assembly.     

Remodeling of cell surface glycoproteins by N-acetylglucosaminyltransferase III gene transfection: modulation of metastatic potentials and down regulation of hepatitis B virus replication

OBJECTIVE: To determine the long-term prognosis of neurologic involvement in Beh?et syndrome. DESIGN: Forty-six patients with Beh?et syndrome, who had been the subjects of a previous report with short-term follow-up, were reexamined 7 years later; 42 of them could be reexamined neurologically. Neuropsychological testing, magnetic resonance imaging, electromyography, and evoked potential studies were performed when available. RESULTS: Of the 27 patients who had had headaches without any neurologic symptoms or signs previously, 2 had developed an acute neurologic attack. In addition, 7 patients in this group showed minor abnormalities on neurologic examination and/or other laboratory investigations, without history of any attacks. Among the previous neuro-Beh?et group (n = 15), as defined by the presence of neurologic signs or symptoms, other than headache, 7 had a stationary course, while 8 had been progressive. Three of the latter group had died. Patients with progressive course had had abnormal cerebrospinal fluid findings at the time of the previous report, whereas patients with a stationary course had not. CONCLUSIONS: Silent neurologic involvement may occur in Beh?et syndrome. Patients should undergo periodic neurologic evaluation. The long-term prognosis in neuro-Beh?et syndrome does not seem to be as favorable as we observed in short-term follow-up. Cerebrospinal fluid findings may predict prognosis.     

In vitro transformation by hepatitis B virus DNA

There is strong epidemiological evidence that the hepatitis B virus (HBV) contributes to the development of hepatocellular carcinoma (HCC). In several immortalized cell lines, an in vitro transforming activity of HBV DNA and expression vectors for the viral protein X (HBx) has now been demonstrated. Furthermore, it appears as if still unknown parts of the HBV genome other than HBx contribute to the transforming activity of HBV DNA in vitro. Only one of several studies found that HBx-transgenic mouse lines develop HCC. A mouse line transgenic for the large surface protein of HBV develops HCC due to concomitant necroinflammatory infection. Growing evidence shows the importance of recombination of integrated viral DNA and cellular DNA for HCC development. A direct transforming potential of one of these viral integrates has been demonstrated. Chemical carcinogens are more effective in HBV-containing cell lines or transgenic mice.     

Serosurvey of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus infection among hospital-based surgeons. Serosurvey Study Group

BACKGROUND: Because occupational blood contact places health-care workers at risk for infection with bloodborne pathogens, we wanted to estimate the prevalence of infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) among hospital-based surgeons and correlate the results with occupational and nonoccupational risk factors. STUDY DESIGN: All surgeons in training or in practice in general surgery, obstetrics and gynecology, or orthopedics at 21 hospitals in moderate to high AIDS incidence areas were eligible to participate in a voluntary, anonymous serosurvey. Serum samples were tested for HIV antibody, for HCV antibody, and for markers of HBV infection: hepatitis B surface antigen, total antibody to hepatitis B core antigen, and antibody to hepatitis B surface antigen. RESULTS: Of 2,887 eligible surgeons, 770 (27 percent) participated in the study. One of 740 surgeons not reporting nonoccupational risk factors was HIV seropositive (0.14 percent, upper limit 95 percent confidence interval [CI] equals 0.64 percent). None of 20 participants reporting nonoccupational HIV risk factors and none of ten not responding to the question on nonoccupational risk factors were HIV positive. Of 129 (17 percent) participants with past or current HBV infection, three (0.4 percent) had chronic HBV infection; all were negative for hepatitis B e antigen. Risk factors for HBV infection included not receiving hepatitis B vaccine (odds ratio [OR] 14.7, 95 percent CI 8.3 to 26.0) and practicing surgery at least ten years (OR 2.2, 95 percent CI 1.3 to 3.8). Seven (0.9 percent) participants had anti-HCV. CONCLUSIONS: Although not necessarily generalizable to all surgeons in moderate to high AIDS incidence areas, these results do not indicate a high rate of previously undetected HIV infection among surgeons who trained or practiced in these areas, or both. Hepatitis B virus posed the highest risk of infection with a bloodborne pathogen, followed by HCV and HIV.     

Seroprevalence survey of Egyptian tourism workers for hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and Treponema pallidum infections: association of hepatitis C virus infections with specific regions of Egypt

Blood samples from 740 Egyptian Nationals working in the tourism industry at two sites in the South Sinai governorate were screened for markers of infection with hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Treponema pallidum. Study subjects included 467 individuals from a rural seashore tourist village and 273 persons at two hotels in a well-established resort town. Subjects' ages ranged from 15 to 70 years; 99.3% were male. The prevalence of serologic markers for currently asymptomatic or past HBV infection alone was 20.7% (n = 153), of markers for past or chronic HCV infection alone was 7.4% (n = 55), and of markers for both HBV and HCV was 6.9% (n = 51). Of the 204 individuals positive for anti-HBV core antibody, 12 (5.9%) were also positive for hepatitis B surface antigen. Two individuals (0.3%) had a serologic market suggestive of an active syphilitic infection. No subject was found to be HIV-seropositive. History of prior injections and number of injections were associated with infection with HCV. Primary residence in the Nile delta and valley areas where schistosomiasis is highly endemic, was also a statistically significant risk factor for HCV, but not HBV infection.     

Seroepidemiologic investigations of human hepatitis caused by A, B, and a possible third virus

The results of magnet implantation in the upper and lower eyelids of 29 patients suffering from Keratopathia due to lagophthalmos due to facial palsy as well as the surgical techniques involved are described. Contrary to a lateral tarsorrhaphy - still popular today - this method does not alter the form or the size of the palpebral fissure nor does it hinder the visual field. It is technically simple to perform and easily reversible should nerve function recover. The subjective results were also good.     

The elimination of hepatitis B virus infection: changing seroepidemiology of hepatitis A and B virus infection in Okinawa, Japan over a 26-year period

Serial changes in hepatitis A virus (HAV) and B virus (HBV) markers were determined from 1970 to 1996 in healthy Japanese residents of a rural area of Okinawa, Japan. All 190 serum samples taken in 1970, 791 in 1980, 708 in 1988, and 523 in 1996 from residents 0 to more than 60 years of age were tested for antibody to HAV (anti-HAV), antibody to hepatitis B core antigen (anti-HBc), and hepatitis B surface antigen (HBsAg). The age-adjusted prevalences of anti-HAV and anti-HBc decreased significantly from 83.9% and 74.9%, respectively, in 1970 to 39.7% and 36.6%, respectively, in 1996. In residents < or = 29 years of age, the prevalences of anti-HAV and anti-HBc decreased significantly from 65.3% and 83.8%, respectively, in 1970 to 0.7% and 8.2%, respectively, in 1996. The age-adjusted HBsAg prevalence decreased significantly from 8.2% in 1980 to 4.1% in 1988. These results indicate that exposure to HAV and HBV infections among Okinawa residents less than 29 years of age is decreasing, probably because of improvements in socioeconomic conditions since 1970. Infection with HBV may be eliminated there in the near future.     

The natural course of hepatitis B and hepatitis C virus infection

Chronic hepatitis B and hepatitis C virus infections maintain a significant risk for the development of liver cirrhosis and hepatocellular carcinoma and cause a considerable morbidity in the population. Among patients with chronic HBV infection and histologically confirmed hepatitis the annual incidence of liver cirrhosis is 2%. The risk for hepatocellular carcinoma in chronic HBsAg carriers is elevated about 40-230 fold. 20-30% of patients with chronic HCV infection will develop cirrhosis over 20-30 years. Hepatocellular carcinoma evolves yearly in about 3% of patients with chronic HCV infection and cirrhosis, whereas HCV-carriers without cirrhosis usually do not develop hepatocellular carcinoma. The high incidence of serious sequelae warrants a regular surveillance of chronic virus carriers.     

Quantification of infectious duck hepatitis B virus by radioimmunofocus assay

We studied whether a flow-independent increase of luminal wall shear stress (WSS) could dilate hamster arterioles in vivo and which endothelial mediators are potentially involved. To this end the plasma viscosity was elevated by exchanging blood for dextran-erythrocyte solution thereby augmenting WSS. Diameters of small and large arterioles as well as red blood cell velocities were measured before and after exchange of blood for solutions of identical haematocrit containing either high- (HMWD) or low-molecular weight dextran (LMWD). The potential role of endothelial autacoids was investigated by local application of the NO-synthase inhibitor NG-nitro-L-arginine (L-NNA), the inhibitor of cyclooxygenase, indomethacin (3 microM), or the K+-channel blocker, tetrabutylammonium (TBA, 0.1 mM) to assess the potential effects of EDHF. HMWD (n = 11 animals) increased plasma viscosity by 64 +/- 3% and dilated arterioles of all branching orders (A1-A4) significantly [by 24 +/- 3% (A1-A2) and 32 +/- 3% (A3-A4)]. This dilation compensated fully for the calculated initial increase of WSS. LMWD (n = 6) did not affect plasma viscosity or arteriolar diameters. Tissue treatment with L-NNA (30-300 microM, n = 12) substantially diminished the HMWD-induced dilation in small arterioles (A3-A4; to 13 +/- 3%; P<0.05) and virtually abolished it in large ones (A1-A2). Consequently, the calculated WSS increased significantly in these arterioles (by 31 +/- 5%). TBA combined with L-NNA (n = 4) did not reduce further the remaining dilation. Indomethacin (n = 6) had no effect on HMWD-induced dilation. We conclude that an increase of WSS induces a mainly NO-mediated arteriolar dilation. This dilation occurs in all arteriolar branching orders and is of sufficient magnitude to compensate for the initial WSS-increase. Thus, any elevations of WSS fulfil the requirement for a signal to change diameter along the arteriolar tree in a coordinated manner. The fully compensating dilation which we observed indicates that WSS is a controlled variable. It does, however, raise questions as to its role as a continuous endothelial stimulus.     

Photochemical inactivation of duck hepatitis B virus in human platelet concentrates: a model of surrogate human hepatitis B virus infectivity

BACKGROUND: Photochemical decontamination of platelet concentrates (PCs) has been demonstrated by the use of 8-methoxypsoralen and ultraviolet A light. Systems for studying the inactivation of blood-borne viruses facilitate the evaluation of photochemical decontamination protocols. STUDY DESIGN AND METHODS: Duck hepatitis B virus (HBV), a model for human HBV, was adapted for the study of hepadnavirus inactivation. A highly specific in vitro infectivity assay used primary duck hepatocyte cultures and was followed by the detection of replicated duck HBV sequences. RESULTS: Duck HBV-infected primary duck hepatocyte cultures produced authentic infectious virus. High-titer (> 10(9) virus genome equivalents/mL) duck HBV-infected sera were completely inactivated in serum or PCs by the use of 100 micrograms per mL of 8-methoxypsoralen and 70 J per cm2 of ultraviolet A light. Intracellular duck HBV (> 4.2 log10) in PCs was also inactivated. Culture results were confirmed by a sensitive duckling infectivity assay that indicated that 6.3 log10 of infectious duck HBV had been inactivated by photochemical decontamination. CONCLUSION: The sensitivity of the culture assay was comparable to that of the duckling assay using polymerase chain reaction gene amplification to detect duck HBV. Duck HBV inactivation in PCs was dependent on the dose of ultraviolet A light and independent of 8-methoxypsoralen concentrations of 100 to 300 micrograms per mL: 100 micrograms per mL 8-methoxypsoralen inactivated 4 to 5 log10 of virus in conjunction with 20 to 40 J per cm2 of ultraviolet A light. The polymerase chain reaction-enhanced duck HBV culture system has utility in optimizing photochemical decontamination protocols.