Phenotype, treatment practice and outcome in the cobalamin-dependent remethylation disorders and MTHFR deficiency: Data from the E-HOD registry

AIM

To explore the clinical presentation, course, treatment and impact of early treatment in patients with remethylation disorders from the European Network and Registry for Homocystinurias and Methylation Defects (E-HOD) international web-based registry.

RESULTS

This review comprises 238 patients (cobalamin C defect n = 161; methylenetetrahydrofolate reductase deficiency n = 50; cobalamin G defect n = 11; cobalamin E defect n = 10; cobalamin D defect n = 5; and cobalamin J defect n = 1) from 47 centres for whom the E-HOD registry includes, as a minimum, data on medical history and enrolment visit. The duration of observation was 127 patient years. In 181 clinically diagnosed patients, the median age at presentation was 30 days (range 1 day to 42 years) and the median age at diagnosis was 3.7 months (range 3 days to 56 years). Seventy-five percent of pre-clinically diagnosed patients with cobalamin C disease became symptomatic within the first 15 days of life. Total homocysteine (tHcy), amino acids and urinary methylmalonic acid (MMA) were the most frequently assessed disease markers; confirmatory diagnostics were mainly molecular genetic studies. Remethylation disorders are multisystem diseases dominated by neurological and eye disease and failure to thrive. In this cohort, mortality, thromboembolic, psychiatric and renal disease were rarer than reported elsewhere. Early treatment correlates with lower overall morbidity but is less effective in preventing eye disease and cognitive impairment. The wide variation in treatment hampers the evaluation of particular therapeutic modalities.

CONCLUSION

Treatment improves the clinical course of remethylation disorders and reduces morbidity, especially if started early, but neurocognitive and eye symptoms are less responsive. Current treatment is highly variable. This study has the inevitable limitations of a retrospective, registry-based design.

Dynamical transition of protein-hydration water

Thin layers of water on biomolecular and other nanostructured surfaces can be supercooled to temperatures not accessible with bulk water. Chen et al. [Proc. Natl. Acad. Sci. U.S.A. 103, 9012 (2006)]10.1073/pnas.0602474103 suggested that anomalies near 220 K observed by quasielastic neutron scattering can be explained by a hidden critical point of bulk water. Based on more sensitive measurements of water on perdeuterated phycocyanin, using the new neutron backscattering spectrometer SPHERES, and an improved data analysis, we present results that show no sign of such a fragile-to-strong transition. The inflection of the elastic intensity at 220 K has a dynamic origin that is compatible with a calorimetric glass transition at 170 K. The temperature dependence of the relaxation times is highly sensitive to data evaluation; it can be brought into perfect agreement with the results of other techniques, without any anomaly.

Dynamics of well-folded and natively disordered proteins in solution: a time-of-flight neutron scattering study

Casein proteins belong to the class of natively disordered proteins. The existence of disordered biologically active proteins questions the assumption that a well-folded structure is required for function. A hypothesis generally put forward is that the unstructured nature of these proteins results from the functional need of a higher flexibility. This interplay between structure and dynamics was investigated in a series of time-of-flight neutron scattering experiments, performed on casein proteins, as well as on three well-folded proteins with distinct secondary structures, namely, myoglobin (alpha), lysozyme (alpha/beta) and concanavalin A (beta). To illustrate the subtraction of the solvent contribution from the scattering spectra, we used the dynamic susceptibility spectra emphasizing the high frequency part of the spectrum, where the solvent dominates. The quality of the procedure is checked by comparing the corrected spectra to those of the dry and hydrated protein with negligible solvent contamination. Results of spectra analysis reveal differences in motional amplitudes of well-folded proteins, where beta-sheet structures appear to be more rigid than a cluster of alpha-helices. The disordered caseins display the largest conformational displacements. Moreover their global diffusion rates deviate from the expected dependence, suggesting further large-scale conformational motions.

[Prevalence of and factors associated with hepatitis B virus markers in a rural population of central Brazil]

OBJECTIVE

To carry out a survey of hepatitis B virus seroepidemiology in a municipality in central Brazil, on the border of two large ecosystems, the cerrado (savanna) and the Amazon River basin.

METHODS

The municipality studied, Nova Mutum, is located in the north central portion of the Brazilian state of Mato Grosso. The study sample of 754 individuals included persons from families, selected at random, who were living in the municipality's urban center as well as all the individuals living in a nearby rural village. Ages ranged from 2 to 79 years. All eligible individuals were interviewed. Blood was collected and used to assess hepatitis B virus markers by enzyme-linked immunosorbent assay.

RESULTS

Hepatitis B virus infection was found in 232 individuals, or 31% of them; 19 of them (3%) were HBsAg-positive. Of the 754 persons, 149 of them (20%) who reported having been vaccinated against hepatitis B and who presented anti-HBs positivity were classified as vaccine responders. With the multivariate analysis, the variables found to be associated with exposure to hepatitis B virus were having begun sexual relations, having been vaccinated against yellow fever with a needle-free jet injection gun (for the age group < 20 years), and being an immigrant from southern Brazil (> 20 years). Vaccine coverage was low among individuals older than 10 years. The largest share of susceptible individuals (74%) were found in the age group of 11 to 20 years.

CONCLUSIONS

Our data suggest that hepatitis B virus vaccine coverage in Brazil should be extended to include teenagers in populations that have a low to moderate hepatitis B virus prevalence. It is likely that our results can be extrapolated to other areas of Latin America with a similar epidemiological pattern.

Seroprevalence of viral hepatitis in riverine communities from the Western Region of the Brazilian Amazon Basin

The western region of the Brazilian Amazon Basin has long been shown to be a highly endemic area for hepatitis B and hepatitis D viruses. Data concerning the prevalence of hepatitis C and E viruses in this region are still scarce. In this study we investigated the presence of hepatitis A, B, C, D and E viruses infection in communities that live along the Purus and Acre rivers in the states of Acre and Amazonas within the Amazon Basin. A total of 349 blood samples were collected and tested for hepatitis A-E serological markers (antibodies and/or antigens) using commercial enzyme linked immunosorbent assays. Anti-HCV positive sera were further assayed by an immunoblot. HBsAg positive sera were subtyped by immunodifusion. The overall prevalence for hepatitis A, B, C, and E were 93.7%, 66.1%, 1.7%, and 4%, respectively. A very high prevalence of delta hepatitis (66.6%) was found among HBsAg positive subjects. Hepatitis A, B and D viruses were shown to be largely disseminated in this population, while hepatitis C and E viruses infection presented low prevalence rates in this region. The analysis of risk factors for HBV infection demonstrated that transmission was closely associated with sexual activity.

Prevalence of hepatitis B and C virus markers among malaria-exposed gold miners in Brazilian Amazon

Hepatitis B and C virus markers were assessed during a survey on malaria in gold mine camps in southern Brazilian Amazon in order to identify risk factors associated to these viral diseases. The study comprised 520 subjects, most of them were gold miners. Missing subjects totaled 49 (8.6%). Among these 520, 82.9% had HBV markers and 7.1% were HBsAg positive. Previous hospitalization, surgery, sexually transmitted diseases and incarceration were quite common among surveyed people, but there is no association between total HBV markers and these factors. On other hand, HBsAg was independently associated to history of sexually transmitted diseases and history of surgery after adjustment. The most frequent HBsAg subtypes identified, adw2 (59%), predominates in populations of Northeast Brazil. The most surveyed people were immigrants coming from that area suggesting that immigrants carried HBV themselves to the study area. Immunoblot (RIBA) confirmed-anti-HCV were found in 2.1%. The only variable associated to anti-HCV in multivariate analysis was illicit intravenous drug. Lack of HCV infection in subjects with such a high HBV markers prevalence reinforces the opinion that HCV is transmitted by restricted routes when compared to HBV. Furthermore, gold miners in Amazon may be considered as a risk group for HBV infection, but not for HCV.

Infection with hepatitis A and TT viruses and socioeconomic status in Rio de Janeiro, Brazil

The prevalence of antibodies directed against the enterically transmitted hepatitis A virus (HAV) was measured in 2 groups of people living in Rio de Janeiro, Brazil. Of 1,056 health care workers (HCWs), 778 (73.7%) were anti-HAV positive. A high prevalence of anti-HAV antibodies (85.7%) was also found among 274 voluntary blood donors (BDs). TT virus (TTV) is a DNA virus that has been found in the sera of patients with post-transfusion hepatitis of unknown etiology. Occurrence of virus shedding suggests that the fecal-oral route may be an important mode of TTV transmission, particularly in the developing world. The presence of TTV DNA was analyzed by PCR in the sera of 191 HCWs and 151 BDs. TTV was detected in 65.4% of HCWs and 79.5% of BDs. In both groups, a family income of < US$400 per month and a level of education of < 11 y of schooling were found to be risk factors for HAV infection. Furthermore, a low family income was associated with TTV viremia in the HCW group. However, the presence of TTV DNA was associated with neither low level of education nor anti-HAV positivity.

Hepatitis E virus infection in selected Brazilian populations

A retrospective study on the prevalence of hepatitis E virus (HEV) infection was conducted in selected populations in Rio de Janeiro, Brazil. A total of 1,115 subjects were tested including 146 patients with acute Non-A Non-B Non-C (NANBNC) viral hepatitis, 65 hemodialysis patients, 93 blood donors, 102 intravenous drug users (IVDUs), 304 pregnant women, 145 individuals living in the rural area and 260 individuals living in the urban area. In order to characterize a favorable epidemiological set for enterically transmitted infection in the studied populations we also evaluated the prevalence of anti-HAV IgG (hepatitis A virus) antibodies. Specific antibodies to HEV (anti-HEV IgG) were detected by a commercial EIA and specific antibodies to HAV (anti-HAV IgG) were detected using a competitive "in house" EIA. We found a high prevalence of anti-HAV IgG in these populations, that could indicate some risk for infections transmitted via the fecal-oral route. The anti-HEV IgG prevalence among the different groups were: 2.1% in patients with acute NANBNC viral hepatitis, 6.2% in hemodialysis patients, 4.3% in blood donors, 11.8% in IVDUs, 1% in pregnant women, and 2.1% in individuals form the rural area. Among individuals living in the urban area we did not find a single positive serum sample. Our results demonstrated the presence of anti-HEV IgG in almost all studied populations; however, further studies are necessary to establish the real situation of HEV epidemiology in Rio de Janeiro, Brazil.

[Serological markers of hepatitis B in users of services at an HIV Testing Center]

The objective of this investigation was to study the prevalence of serological markers of hepatitis B and possible risk factors for this disease in a sample of 404 people who attended a Testing and Couseling Center for HIV in the city of Ribeirão Preto, São Paulo State, Brazil. The overall prevalence of serologic hepatitis B markers was 14.6%, equal to that obtained for anti-HBc. HBsAg and anti-HBc IgM showed prevalences of 1%. After adjustment using logistic regression, hepatitis B markers showed association with the following variables: age, place of residence, use of injectable drugs and positivity to anti-HIV. The overall prevalence of human immunodeficiency virus infection was 6.9%. Hepatitis B markers were detected in 55.6% among intravenous drug users and in 42.9% among those who tested positive for HIV, confirming literature findings which indicates high levels of infection in these specific population groups.

[Serological markers of hepatitis B in people submitted to blood testing in health care clinics]

OBJECTIVE

To study some of the epidemiological aspects of hepatitis B in a non-representative sample of patients seen in health care clinics.

METHODS

The study population comprised 632 patients who were seen at health care clinics in the city of Ribeirão Preto, Brazil, for the purpose of blood testing, regardless the reason. After signing a written consent, an additional amount of blood was drawn from the same venous puncture site used to collect the original sample for the testing assigned to the patient at the health care clinic. A questionnaire was applied to each participant, looking for the presence of risk factors for hepatitis B. The blood samples were tested for HBV markers, using immunoenzimatic techniques.

RESULTS

The prevalences of HBsAg and anti-HBcAg were 0.3% and 13.9%, respectively. By a logistic regression model, the following variables were significantly associated with the infection: age, time of residency in the city (higher risk among those living for a period less than one year), past history of hepatitis, incarceration and sexual behavior (higher risk among homosexual and bisexual males).

CONCLUSIONS

The growing difficulties in obtaining blood samples from a representative group of patients, as done in classic surveys, make it necessary to look for alternative methodologies which can provide information concerning the presence of infectious agents in a community. Though the results cannot be generalized to the population as a whole, the methodology used conveyed some knowledge regarding the circulation of hepatitis B virus. In addition, it makes much easier to obtain agreement from the participants, since it does not add any invasive procedure. Despite the limitations, this methodology may be helpful in epidemiological surveillance of infectious agents known as producing asymptomatic infections in much of the population.

Inducible nitric oxide synthase (iNOS) expression in liver and splenic T lymphocyte rise are associated with liver histological damage during experimental hepatitis A virus (HAV) infection in Callithrix jacchus

Callithrix jacchus is considered a reliable animal model for hepatitis A virus (HAV) infection. All three HAV orally inoculated marmosets developed hepatitis - the infection was monitored by continuous virus shedding, high levels of serum enzyme alanine aminotransferase, specific antibody and seroconversion 3-6 weeks after HAV inoculation. HAV antigen was detected in liver by immunofluorescence 4 days post inoculation (PI) and onwards. To gain insight into the biological role of inducible nitric oxide synthase (iNOS) during immune-related acute liver injury the enzyme was searched in frozen biopsies: immunofluorescent labeling was found in the cytoplasm of liver cells mainly Kupffer's cells and spleen macrophages (CD68+) starting 11 days PI with maximum intensity on the fifth to sixth week PI. Necroinflammatory liver lesions characteristic of viral hepatitis were also observed at 10 days PI with maximum severity at 4 to 6 weeks PI. Furthermore, T lymphocytes (CD2+) were raised at this time point. No difference was evident in the frequency of B lymphocytes (CD20+). Therefore, iNOS expression preceded necroinflammatory liver lesion and maximal immunofluorescence reaction was coincident with tissue injury, supporting the hypothesis that NO contributes to hepatic cytotoxic mechanism but also to virus clearance. The concomitant rise in T-lymphocyte population may suggest a role for these cells in this and/or other independent HAV-induced pathological changes.

Hepatitis B virus: genotypes and subtypes in Brazilian hemodialysis patients

There are no data concerning the genotypic analysis of hepatitis B virus (HBV) infection in Brazilian dialysis centers. Serum samples from all hemodialysis patients (n = 282) in Goiânia City, Central Brazil, were tested for hepatitis B surface antigen (HBsAg). An overall prevalence of 12.0% was found, ranging from 0 to 33.3% depending on dialysis centers. Positive samples (n = 34) were submitted to serological subtyping by monoclonal ELISA and HBV DNA detection by polymerase chain reaction (PCR). Among 30 PCR-positive samples, 26 were genotyped by use of the line probe assay technology (INNO-LiPA HBV, Innogenetics, Gent, Belgium). HBV genotypes A (50. 0%) and D (46.2%) were the most frequently found whereas genotype F (3.8%) was rare in this population. Serological subtypes adw2 (44. 1%) and ayw3 (41.2%) were dominant. By contrast, adw4 and ayw2 were found at a low frequency (2.9%). A correlation was observed in the distribution of genotypes and subtypes by dialysis center. Genotype D and subtype ayw3 were predominant in 2 hemodialysis centers whereas genotype A and subtype adw2 were predominant in the others. The findings of high HBsAg prevalence rates restricted to certain dialysis centers and the data obtained through genotyping and serological subtyping suggest HBV nosocomial transmission in these hemodialysis centers.

The use of non-human primates as animal models for the study of hepatitis viruses

Hepatitis viruses belong to different families and have in common a striking hepatotropism and restrictions for propagation in cell culture. The transmissibility of hepatitis is in great part limited to non-human primates. Enterically transmitted hepatitis viruses (hepatitis A virus and hepatitis E virus) can induce hepatitis in a number of Old World and New World monkey species, while the host range of non-human primates susceptible to hepatitis viruses transmitted by the parenteral route (hepatitis B virus, hepatitis C virus and hepatitis delta virus) is restricted to few species of Old World monkeys, especially the chimpanzee. Experimental studies on non-human primates have provided an invaluable source of information regarding the biology and pathogenesis of these viruses, and represent a still indispensable tool for vaccine and drug testing.

Hepatitis B virus infection in immigrants to the southern Brazilian Amazon

To identify epidemiological patterns and risk factors associated with hepatitis B virus (HBV) infection in the southern Brazilian Amazon, a survey was performed in the county of Terra Nova do Norte in the northern part of the state of Mato Grosso. The population consists mainly of immigrants from the southern part of Brazil, where HBV prevalence is low. A random sample (n = 783) of the population was interviewed and tested for HBV markers. The overall prevalence of HBV infection was 54.7%. There were 31 hepatitis B surface antigen (HBsAg) carriers (3.9%), with a low rate of HBV e antigen positivity, and none with anti-hepatitis D virus. Subtypes ayw3 and ayw2 of HBsAg were predominant, suggesting that the immigrants carried HBV from their original region to the Amazon. Clustering of HBV infection within families was found. The association between HBV markers and having lived in a gold-miners' camp, even after adjusting for confounders, indicated that the gold-miners may play a role in HBV spread in areas of the Amazon where gold prospecting occurs.

Age-specific prevalence of antibodies to hepatitis A in children and adolescents from Rio de Janeiro, Brazil, 1978 and 1995. Relationship of prevalence to environmental factors

The age-specific prevalence of antibodies to hepatitis A virus (anti-HAV) was determined in two different population groups with low socio-economic status from Rio de Janeiro city, Brazil, whose serum samples were collected 17 years apart (Population 1, 1978; Population 2, 1995). In Population 2, analysis of the anti-HAV prevalence was also carried out with respect to environmental factors. Population 1 was composed of 520 stored sera collected from the umbilical cord of term neonates and children aged 1 month to 6 years. In population 2, 720 serum samples were collected from children and adolescents with ages ranging from 1 to 23 years. The overall prevalence rate of anti-HAV in Population 1 and Population 2 was 65.6% and 32.1%, respectively. In Population 1, the anti-HAV prevalence reached 88% at the age of 3, while in Population 2, it increased from 4.5% in children under the age of 3 to 66% in the group of adolescents over the age of 14. The low exposure to HAV infection in younger children from Population 2 could be a result of improved environmental hygiene and sanitation, as demonstrated by the presence of piped water, waste and sewage disposal systems in most houses from this population group. These findings indicate a possible change in the prevalence of hepatitis A in Rio de Janeiro.

Epidemiological survey of infection with hepatitis B virus in the savannah and wetlands (Pantanal) of central Brazil

An epidemiological survey of the prevalence of hepatitis B virus (HBV) was conducted in the county of Nossa Senhora do Livramento, Mato Grosso state, central Brazil. This rural county has a largely stationary population of low socio-economic status, and is divided into savannah-type vegetation and wetland. Overall, 740 subjects aged > 9 years were selected at random, interviewed and bled so that seropositivities of various HBV markers (surface antigen and antibodies to this antigen and to core antigen) could be determined. At least one marker was found in 169 (22.8%) of the subjects but only nine (1.2%) carried the surface antigen. Vegetation type (wetland v. savannah) was not associated with HBV infection but male gender, increasing age, and having had sexual experience were each associated with the infection. The prevalence of HBV markers was higher in immigrants (32.5%) than in native individuals (21.1%), many immigrants apparently having acquired the infection before settling in the study area.

Western blot analysis of the reactivity between envelope proteins of hepatitis B viruses from Brazilian carriers and antibodies raised against recombinant hepatitis B vaccines

A Western blot assay was standardized to evaluate the antigenic reactivity of hepatitis B virus (HBV) strains circulating in Brazilian population with antibodies raised against recombinant hepatitis B (HB) vaccines. In this assay, HBV envelope proteins from infected human blood were detected by antibodies from rabbits immunized with either of two recombinant vaccines. These were Engerix B (Smith Kline Beecham, Belgium) containing exclusively S protein particles and TGP-943 (Takeda Chemical Industries, Japan) containing M protein particles. Forty-seven serum samples, presenting HB surface antigen. (HBsAg) reverse passive haemagglutination assay (RPHA) titers ranging from 1:32 to > or =1:4096 after HBV particles concentration, were tested. Twenty-seven samples were from acute hepatitis cases and 20 were from chronic cases (11 from cirrhotic patients and 9 from asymptomatic carriers). Four HBV serotypes, adw2, adw4, ayw2 and ayw3, were identified in these samples. Infectivity of these sera was evaluated by HBV DNA detection by polymerase chain reaction (PCR). HBV DNA was present in 62% of samples from acute cases and in all samples from chronic cases. Despite the differences between serotypes, genotypes, forms of infection, and infectivity of the samples, antibodies against both vaccines reacted with HBV envelope proteins from all but one sample. In one sample from cirrhotic patient, only a small protein of unexpected size reacted with TGP-943 antibodies.

Intragastric infection induced in marmosets (Callithrix jacchus) by a Brazilian hepatitis A virus (HAF-203)

Several species of non-human primates have been used in studies on experimental infection with hepatitis A virus (HAV). Attempts to infect a South-American marmoset (Callithrix jacchus) with a Brazilian HAV isolate (HAF-203) are described here. Four seronegative animals were inoculated intragastrically and one was sacrificed on day 11, 20, 47 and 62 after infection. One uninfected animal was included as control. Liver, small intestine, lymph node, spleen and kidney samples were collected for histological diagnosis and immunocytochemistry studies. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serum enzymes and anti-HAV antibodies were monitored by a colorimetric procedure (Abbott) and an enzyme immunoassay (ELISA), respectively. Feces were collected daily for HAV antigen (HAVAg) detection by ELISA. Increased levels of HAVAg were detected in hepatocytes 11 days after infection, with a gradual decrease during the course of infection. Shedding of HAVAg in feces was observed from the late incubation to the early acute phase (20th day to 47th day after infection). The end of the incubation period was indicated by the initial increases in serum ALT and AST. Severe hepatic lesions such as piecemeal necrosis and bridging necrosis were detected during the acute phase, coinciding with the maximum transaminase levels and the appearance of anti-HAV antibodies. On the 62nd day (convalescent phase), the hepatic tissue showed evidence of regeneration and the transaminase values had returned to baselines. The serological, biochemical, antigenic and histological evidence of hepatitis A was similar to that observed in several primate models inoculated with other HAV isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein glycation and in vivo distribution of human lens fluorescence

Glycated proteins formed by the Maillard reaction were measured by furosine determination in human normal lenses and in senile and diabetic cataracts. Furosine, an hydrolysis product of fructose-lysine adduct formed in the early stages of the Maillard reaction, was measured by high performance liquid chromatography (HPLC). Furosine levels in diabetic cataracts were found to be 3 to 4 times higher than those observed for senile cataracts. The increased glycation levels both in cortex and nucleus were related to the increase of fluorescence determined in vitro by fluorometry and in vivo by Scheimpflug photography. Lens proteins were incubated with glucose and it has been demonstrated that protein glycation occurred parallel with the increase in concentration of fluorescent chromophores that present similar characteristics as those observed in vivo. The results indicate that protein insolubilization seemed to involve preferentially glycated proteins and at least in diabetic cataracts, the process seems to be initiated in the cortical region.

Genetic diversity of hepatitis B virus strains isolated in Rio de Janeiro, Brazil

Hepatitis B virus (HBV) genomes have been classified into six groups, A-F, group F being the most divergent. South America has provided the smallest number of strains studied at the genome level. The only HBV strain from this region sequenced completely has been classified in group F, and contains the most divergent of the HBV genomes presently known [Naumann et al. (1983): Journal of General Virology 74:1627-1632]. To evaluate genetic relatedness between strains isolated in South America and in the rest of the world, a restriction endonuclease analysis was carried out on 14 HBV strains (4 adw2, 3 adw4, 3 ayw2, and 4 ayw3) isolated in Rio de Janeiro, Brazil. C, pre-S, and X genes along with the 5' part of the P gene from these strains were amplified by the polymerase chain reaction. The DNA fragments were digested by BamHI, BstEII, EcoRI, HhaI, and TaqI endonucleases. The restriction patterns obtained were compared with those deduced from the nucleotide sequence of 26 HBV strains isolated in other continents. The results showed a large genetic variability of Brazilian strains. Taking into account that all the samples examined possessed the w antigenic subdeterminant, the number of different restriction patterns of strains isolated in Rio de Janeiro was at least as large as that of the reference strains isolated in the rest of the world. Some original restriction patterns were found in adw4 and ayw2 HBV strains.

Identification of a new hepatitis B virus (HBV) genotype from Brazil that expresses HBV surface antigen subtype adw4

The complete genome of a hepatitis B virus (HBV) from Brazil that expressed the subtype adw4 of HBV surface antigen (HBsAg) was cloned and sequenced. The genome, termed w4B, consists of 3215 bp. The overall genetic organization of typical hepadnaviruses with four open reading frames including the preC region was found to be conserved. When comparing the w4B sequence with 19 complete HBV genomes it was, however, found to be more divergent (15%) than any other HBV sequence thus far reported. Until now, no more than 11% divergence has been reported. Distinct from the five known HBV genotypes A to E, w4B made up a new, sixth genotype. The importance of the conserved third start codon in the HBV X gene became apparent in isolate w4B. By mutation, this ATG was out of frame, and by what appears to have been a linked mutation, a new start site two codons downstream was re-established. The significance of several other mutations is discussed.

[Influence of migration on the prevalence of serologic hepatitis B markers in a rural community. 1. Analysis of prevalence by birthplace]

Distribution of hepatitis B serological markers according to people's birthplaces and area of residence (urban/rural) was studied as a part of a field epidemiological research project carried out in Cássia dos Coqueiros, a small rural community of S. Paulo State, Brazil. The total prevalence of HBV markers was 7.7%, with rural showing a higher risk than urban inhabitants (9.8% as against 4.9%, respectively). Analysis of prevalence according to people's birthplaces revealed the highest value among those from other Brazilian states (15.8%), followed by people from other municipalities of the State of S. Paulo (9.2%). Those born in Cássia dos Coqueiros and particularly in Ribeirão Preto (the main city of the area, located 80 kilometers away), showed the lowest values of prevalence (5.2% and 2.5%, respectively). The importance of studying people's birthplaces when field epidemiological studies on hepatitis B are carried out is stressed. This variable is considered to be capable of exercising an influence on the natural history of the disease in a community, and may even explain differences in the distribution of markers in apparently similar populations.

[Influence of migration on the prevalence of serologic hepatitis B markers in a rural community. 2. Comparative analysis of various characteristics of the population studied]

The association between prevalence of hepatitis B serological markers and birthplace, in a study carried out in a small rural county of S. Paulo State, Brazil, suggests different risk factors for hepatitis B between migrants and nonmigrant populations. These two groups were compared with regard to the following variables: level of education, professional occupation, number of previous hospitalizations, past history of blood transfusions and type of dental treatment. Migrants, mainly those from other states of Brazil, showed a low-level of education, a high proportion of people employed in agricultural activities, a higher number of past hospitalizations and higher exposure to blood transfusion and to more aggressive dental procedures. Associations were observed between the prevalence of serological markers and the following variables: level of education, professional occupation, number of previous hospitalizations and type of dental procedures, even though the last two associations did not justify the higher prevalences observed among migrants. The different distribution of hepatitis B markers seems to be dependent on the migrants' worse socio-economic condition, demonstrated by their lower level of education and by the predominance of secondary occupations.

Fast growth of a Brazilian hepatitis A virus (HAF-203) in a primate cell line

A hepatitis A virus (HAV, HAF-203) isolated in Brazil was submitted to 8 serial passages through fetal Rhesus kidney cells (FRhK-4). The kinetics of replication were monitored by enzyme immunoassay (EIA-HAVAg) and cDNA-RNA dot blot hybridization. The maximum level of RNA, which was observed 21 days post-infection (p.i.) during the 3rd passage, when HAVAg was still undetectable by EIA, served as a basis to establish subsequent passages every 21 days p.i. This schedule of passage resulted in a progressive reduction of time between culture infection and HAVAg and RNA production, together with an enhancement in antigen titer content of cell lysates. During the 7th passage, maximum HAVAg and RNA levels were detected at 7 days. Fourteen days after the 8th passage, clear morphological modifications appeared, suggesting a good adaptation of HAF-203 to FRhK-4 cells. Obtaining a fast-growing Brazilian HAV is very important for the development of vaccines.

The cDNA sequence of the human pro-hormone and pro-protein convertase PC1

Using a probe consisting of the full-length cDNA sequence of the mouse pro-hormone convertase PC1 (mPC1), we isolated from a lambda gt10 human pituitary cDNA library a number of contiguous clones, of which composite sequence of 3.3-kb defined the complete coding sequence of human PC1 (hPC1). The cDNA sequence of hPC1 encodes a protein containing 753 amino acids and potentially two N-glycosylation sites, one carboxy-terminal amidation site, a cAMP-dependent protein kinase Ser phosphorylation site, a tyrosine kinase phosphorylation site, and an ArgGlyAsp (RGD) sequence. Like mPC1, the carboxy-terminal sequence of hPC1 exhibits an amphipathic domain potentially involved in membrane association. The coding region of hPC1 exhibits an overall 92.6% protein sequence identity to the mouse mPC1 sequence, with the highest homology (98%) found in the catalytic segment of the molecule (residues 84-399). Whereas Northern blot analysis of tissues obtained from mouse, rat and porcine demonstrated the presence of two mRNAs of 3 kb and 5 kb, Northern blots of human tissues and cells demonstrated the presence of a dominant transcript of 6.2 kb and the presence of smaller transcripts in some tissues. The major site of production of hPC1 seems to be the pituitary and brain, although detection was also possible in pancreas and heart.

[Prevalence of serological markers of hepatitis B in a small rural community of São Paulo State, Brazil]

Prevalence of three hepatitis B markers was measured by immunoassay techniques in small rural community of the State of S. Paulo, Brazil. Total prevalence was 7.74%, corresponding to values of 0.10%, 1.69% and 7.74% for HBsAg, anti-HBs and anti-HBc, respectively. The importance of anti-HBc determination in such studies is stressed. Comparisons between the low viral circulation observed in this area and high prevalences described in other rural communities may contribute to the raising of new hypothesis concerning alternative transmission mechanisms of hepatitis B.

Hepatitis C virus in chronic hemodialysis patients with non-A, non-B hepatitis

Sixteen of 110 hemodialysis (HD) patients fulfilling criteria of non-A, non B hepatitis (NANBH), i.e. alanine aminotransferase (ALT) greater than 50 U/ml in the absence of both serologic markers for acute HBV and HAV infections and clinical evidence of another cause of hepatitis, were tested for the presence of antibodies against hepatitis C virus (anti-HCV) by enzyme immunoassay (Ortho, Diagnostics). All (100%) were anti-HCV-positive. There were 5 patients with a monophasic (M) rise pattern (1 or 2 ALT rises), and 11 cases demonstrated a polyphasic (P) rise elevation pattern (more than 2). The mean ALT value of the M group was 202.3 +/- 209 U/ml and that of the P group was 116.6 +/- 39.1 U/ml. The patients received a mean of 19.1 +/- 16.2 units of packed red cells during the follow-up period (69.9 months). Only 1 patient received no blood transfusion. Six patients had a past HBV infection and 3 became HIV-infected in the course of this study. The high rate of infection of hemodialysis patients with hepatitis C virus in our setting points to the need for improved control measures.

Two competitive enzyme immunoassays for the detection of IgG class antibodies to hepatitis A antigen

Two competitive enzyme immunoassays (EIA) techniques were developed: in the first (COMP-1), test sera were added together with HAV antigen on anti-HAV IgG-coated wells followed by an anti-HAV HRP conjugate; in the second (COMP-2), test sera and anti-HAV HRP conjugate competed for HAV epitopes previously adsorbed to anti-HAV IgG-coated wells. Both procedures used tetramethylbenzidine (TMB) as a substrate. Both competitive tests were shown to be reproducible and suitable for routine diagnosis and research purposes.

[Incidence of non-A, non-B hepatitis at a hemodialysis unit]

A monitorização mensal de alanina aminotransferase (ALT) sérica de pacientes em hemodiálise e os testes sorológicos para exclusões de infecções por vírus da hepatite A (HAV), vírus da hepatite B (HBV), citomegalovirus (CMV) e vírus Epstein-Barr (EBV), permitiu-nos identificar 11 casos de hepatites não-A, não-B em 111 indivíduos avaliados durante o período de 12 meses e acompanhados por 2 anos. Foram observados 3 padrões de atividade de ALT: elevação em pico monofásico em 2, bifásico ou polifásico em 6 e em platô em 3 pacientes. Individíduos com padrão monofásico exibiram os níveis mais elevados de ALT. Cinco pacientes apresentaram normalização bioquímica persistente 4,8 meses em média após o início da elevação aguda e seis evoluíram com ascensão crônica de ALT durante o período de estudo. A hepatite não-A, não-B foi, predominantemente, assintomática e anictérica, sempre antecedida por transfusões sangüíneas e com maior incidência nos seis primeiros meses de terapia dialítica dos pacientes.

Comparative ELISA reagents for detection of hepatitis B surface antigen (HBsAg)

Conjugates of goat anti-HBs IgG and horseradish peroxidase (HRP) prepared by two different methods, one using NaIO4 and the other SPDP, were compared. Anti-HBs antibodies obtained from goat, rabbit and guinea-pig were tested as capture serum. The ELISA showed a sensitivity similar to RIA and a level of antigen captation ranging from 4.37 to 8.75 nanograms/ml was obtained when rabbit or guinea-pig captures were used combined with both NaIO4 or SPDP conjugates.

Geographic distribution of HBsAg subtypes in Brazil

HBsAg positive serum samples (896) from five brazilian regions were analysed for HBsAg subtypes. The presence of five different subtypes (ayw2, ayw3, ayw4, adw2 and adw4) was detected. In Northern region subtypes adw4 (41.2%) and adw2 (37.2%) were predominant. In the North East only subtype adw2 was encountered. In Central West, South-East and South, subtypes ayw2, ayw3, adw2 and adw4 were present, with predominance of adw2 in Central West and South East (84.3% and 69.4% respectively) whereas in the South the predominant subtype was ayw3 (41.9%) followed by ayw2 (36.4%). Subtypes ayw1, ayr and adr were not found among the samples studied. These results show the difference in the incidence of HBsAg subtypes in the different regions of Brazil and their significance in relation to the colonization and migrations in this country.

Hepatitis B serological patterns of asymptomatic carriers in an endemic region and evaluation of blood plasma as a source of hepatitis B vaccine

Hepatitis B serological studies were carried out in 251 asymptomatic carriers of HBsAg living in an endemic rural area of Cachoeiro do Itapemirim (545 km distant from Rio de Janeiro) in order to evaluate this population as a potential source of blood plasma for hepatitis B vaccine production. A pilot study on HBsAg purification from plasma was also performed to estimate antigen yield.

[Anti-HBs antibodies from rabbits and their use as reagents for serological tests in the diagnosis of hepatitis B]

By the method of affinity chromatography a partially purified antigen was obtained after passing the plasma of an asymptomatic carrier of HBsAg through a column of Sepharose 4B linked to angi-HBs. This antigen was inoculated in rabbits using a schedule of 1,0 mg in the first dose and 4 other doses of 0,5 mg with intervals of approximately 15 days. Observing that blood samples collected after the 5th inoculation showed no change in antibody levels, the animals were bled on the 62th day and these immune sera were standardized with the following tests for the detection of HBsAg: Reverse passive hemagglutination (R-PHA) - using specific gamma globulin that was obtained from rabbit sera by affinity chromatography and reaching an optimal concentration of 10 micrograms/ml to sensitise SRBC at 5% fixed in glutaraldehyde. Counter immuno electrophoresis (CIEP) - using the rabbit immune sera diluted to 1/20 as a reagent for the detection of HBsAg. The immune sera was also used to conjugate new Sepharose 4B for affinity chromatography and was found having a linking capacity of approximately 0,5 to 1,0 mg of HBsAg per ml of Sepharose after complete saturation.

A water-borne hepatitis A outbreak in Rio de Janeiro

An excess of hepatitis cases, in the research center of Petrobrás located in the Fundaão Island, within the city of Rio de Janeiro, was notified during the second half of March 1980. In recent years this center has had an average of four cases per year, but between March 5th and April 25th, sixteen cases were reported. The cause and possible source of infection were investigated. A serologic diagnosis of hepatitis A was made by showing IgG serum antibodies against this virus in patients. No subclinical cases among a group of 60 healthy employees could be identified. A questionnaire was circulated to investigate a possible commom source of infection. Evaluation of the water supply system indicated that it had recently been contaminated. Information obtained from other medical services in the island failed to reveal that the episode was part of a larger outbreak.