Transcriptional regulation of the apolipoprotein B100 gene: purification and characterization of trans-acting factor BRF-2

Apolipoprotein B100 (apoB), the only protein of low-density lipoprotein, is produced primarily in the liver and serves as a ligand for the low-density lipoprotein receptor. Hepatic cell-specific expression of the human apoB gene is controlled by at least two cis-acting positive elements located between positions-128 and -70 (H. K. Das, T. Leff, and J.L. Breslow, J. Biol. Chem. 263:11452-11458, 1988). The distal element (-128 to -85) appears to be liver specific since it shows positive activity in HepG2 cells and negative activity in HeLa cells. The proximal element (-84 to -70) acts as a positive element in both these cell lines, and two rat liver nuclear proteins, BRF-1 and C/EBP, bind to two overlapping sites (-84 to -60 and -70 to -50, respectively). By gel mobility shift assay, we have identified a rat liver nuclear protein (BRF-2) which binds to the distal element (-128 to -85) of the apoB gene. This putative trans-acting factor has been purified to apparent homogeneity by DEAE-cellulose, heparin-agarose, and DNA-specific affinity chromatography. The purified BRF-2 has an apparent molecular mass of 120 kDa and was found to specifically recognize sequence -128 to -85; BRF-2 also produced a strong hypersensitive site at nucleotide position -95 with copper-orthophenanthroline reagent. A double-stranded oligonucleotide (-128 to -85) containing a 3-nucleotide (TTC) insertion between position -95 and -94 was found to abolish DNA binding by BRF-2. This result suggests that the region surrounding the hypersensitive site -95 is important for protein-DNA interaction. By using apoB promoter fragments containing various internal deletions as templates for gel mobility shift assay, the region between -104 and -85 was identified to be crucial for binding by BRF-2. We propose that BRF-2 may play an important role in the tissue-specific regulation of apoB gene transcription.

Sequence comparison of the capsid region of hepatitis E viruses isolated from Myanmar and China

Hepatitis E viruses (HEVs) were isolated during epidemics, one from Myanmar (formerly called Burma) and one from China and were partially sequenced. Another HEV Myanmar strain from sporadic hepatitis was previously sequenced by us. A cDNA sequence comparison was performed among them in the 3'-terminal region, approximately 750-base long. This region contained at least two immunological epitopes and was considered to correspond to the structural protein. The nucleotide sequence identity was 97.2% between the two Myanmar strains and 93.3 and 92.5% between the two Myanmar and the China strain. The deduced amino acid sequence identity ranged from 98.4 to 100.0% among the three strains. Thus this segment was well conserved on the amino acid level among the different strains isolated from these two Asian countries, although the China strain diverged more from the Myanmar strains on the nucleotide sequence level. This data may provide important information for the development of a vaccine and for identification of the virological link between different geographical locations.

[Hepatitis E in Hetian city. Analysis of 562 cases]

Between August and September 1987, 562 patients were hospitalized with acute non-A, non-B hepatitis. The male to female ratio was 1.4:1, and 75% of the patients was of 15-40 years of age. Jaundice developed in 87%. The overall case-fatality rate was 1.4%, but it was highest among pregnant women (5.2%) and newborn infants (24.2%). In general, the disease was self-limited with no evidence of chronic infection. Liver biopsies obtained during the acute illness showed portal inflammation and cytoplasmic cholestasis. Of 31 specimens of stool examined with a prototype ELISA for HEV antigen, 8 were found to be 'positive' and confirmed with immune electron microscopy (IEM). IEM examination of 'patients' stool revealed 27-32 nm viruslike particles. Inoculation of rhesus monkeys with patients stool containing virus-like particles produced acute hepatitis and the acute phase serum reacted with these particles in IEM, while preinoculation serum specimens were non-reactive.

Epidemiologic investigation on an outbreak of hepatitis C

An outbreak of hepatitis in plasma donors occurred in a village of Hebei Province in the period of September to October 1985. The morbidity rate was 40.0% (26/65) in the plasma donors, which was significantly higher than that in whole blood donors (1/88) and in persons who were not blood donors (1/400). One to one paired survey was carried out, and the incidence was 46.4% (26/56) in the plasma donors, while there were no such outbreak in the control group. The distribution of cases showed positive correlation with the number of plasma donors from the production brigade. No secondary infection was found in their families. The peak of outbreak was about 2 months later than the peak of plasma donation. 26 cases of hepatitis in plasma donors all showed negative results for anti-HAV IgM, HBsAg, anti-HBC IgM, anti-CMV IgM and anti-EBV IgM. Sera of 25 cases were selected and sent to CDC, USA to confirm with Chiron C100 reagent. 24 cases were anti-HCV positive. This outbreak of hepatitis was demonstrated to be related to cross contamination during plasma donation.

Chemical modification locates guanidinyl and carboxylate groups within the active site of prolidase

Reagents phenylglyoxal or 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate inactivate the enzyme prolidase, with protection conferred by the competitive inhibitor N-acetylproline. The presence of arginine and carboxylate (aspartic/glutamic acid) residues at the active site of this metallodipeptidase may be inferred.

Epidemiology of hepatitis E in China

A total of 9 hepatitis E epidemics have been documented in China since 1982. Five of them were waterborne and four foodborne, and they occurred in 6 of 30 provinces or autonomous regions in the country. The disease most frequently affects young adults, with fewer cases in children and the elderly. A relative male excess of cases has been observed. However, the fatality rate in female patients with hepatitis E is significantly higher than in males. The disease has a distinctive autumn seasonality in endemic areas. A peak of fecal excretion of hepatitis E virus is found at the late incubation period and early acute phase. The incubation period of the disease ranges from 15 to 75 days, with a mean of 36 days. A randomized double-blind and controlled study showed that human immune serum globulin had no prophylactic effects on hepatitis E.

A serological study of hepatitis C infection in plasmapheresis donors

An epidemic of parenterally transmitted non-A, non-B hepatitis (PT-NANBH) occurred in plasmapheresis donors in Guan County, Hebei Province, China, in 1985. PT-NANBH was diagnosed by epidemiological studies and serological exclusion of HAV, HBV, CMV and EBV infections. Recently, 163 sera samples of 108 patients with PT-NANBH and 65 sera samples of 49 cases with elevated alanine aminotransferase (ALT) levels collected during the epidemic were tested by anti-HCV EIA (Chiron C100). The positive rates of anti-HCV in these two groups were 89.8% (97/108) and 93.9% (46/49), averaging 90.8%. The figures increased with the course of illness and persistance of ALT elevation, i.e., 17.6% and 55.6% within 1 month, 88.9% and 87.5% at 6 months and 100% and 100% after 2 years. Five patients with PT-NANBH and 1 with elevated ALT levels were followed up for 3 to 4 years. We demonstrated that anti-HCV remained positive after the disease had resolved and ALT levels had normalized.

Effect of radix Salviae miltiorrhizae extract injection on survival of allogeneic heart transplantation

The effect of Radix Salviae Miltiorrhizae (RSM), a commonly used herbal blood circulation invigorator for the treatment of blood stasis in traditional Chinese medicine, on the duration of allograft survival following heterotopic heart transplantation in experimental animals was observed. The results in three heart transplantation models--auricular free graft in mice, abdominal graft in rats and cervical graft in rabbits--suggested that RSM injection in an appropriate dosage prolonged the survival time of cardiac allograft. The herb showed no significant toxicity. It was also found that RSM injection had a synergic effect with corticosteroids against graft rejection.

[Effect of oxymatrine on prolonging the survival time of cardiac tissue allograft in mice and its immunologic mechanisms]

Oxymatrine is an extract from Sophora flavescens Ait. A daily dose of 75 mg/kg or 225 mg/kg of oxymatrine was given to the recipient intramuscularly for 14 days. The survival time of cardiac tissue allograft was prolonged significantly to 12.2 days (at the dose of 75 mg/kg, P less than 0.05) and 15.7 days (at the dose of 225 mg/kg, P less than 0.001) by oxymatrine, while that in the control group was 10.8 days. The effects of oxymatrine on immune-function in BABL/c mice with or without heart allograft were further studied. Experiments showed that in vitro spontaneous proliferation of spleen cells increased markedly on the 10th day after transplantation, while the proliferation response to Con A of spleen cells decreased. The spontaneous proliferation and proliferation responses to Con A or to LPS of spleen cells could be inhibited significantly in normal mice by oxymatrine. The proliferation response to LPS of spleen cells and RPFC was inhibited obviously in transplanted mice by oxymatrine. However, oxymatrine did not affect the proliferation response to Con A of spleen cells, which had been decreased after transplantation. The results suggested that this drug exhibited selective immuno-suppression on function of B cells without obvious effect on T cell function in transplanted mice. This characteristics of the drug seemed beneficial for avoiding side-effect produced by the conventional immuno-suppressive agents.

Effect of dietary cholesterol on the lipoprotein profile and binding of radioiodinated lipoproteins to hepatic membranes in the cockerel (Gallus domesticus)

1. Cockerels fed a cholesterol-supplemented diet experienced a marked elevation of lipoprotein particles of density less than or equal to 1.006 g/ml (VLDL) and a diminution of lipoprotein particles of density 1.02-1.05 g/ml (LDL). 2. Unlike VLDL of some cholesterol-fed animals, cholesterol-fed cockerel VLDL did not display beta-mobility on agarose gel electrophoresis. 3. [125I]LDL and [125I]HDL binding to cockerel liver membranes was not affected by cholesterol feeding. 4. Different lipoprotein types appear to bind to a common site on cockerel liver membranes. 5. The results suggest that liver cells of cockerels may not possess LDL binding sites that are analogous to those of mammalian species.

Serum high density lipoprotein cholesterol and factors influencing its level in healthy Chinese

Serum HDL-cholesterol (HDLc) levels were studied on 2399 healthy urban inhabitants, from newborn to 78 years of age, in Shanghai. The results were as follows. (1) Frequency distribution of serum HDLc levels in most groups was approximately normal after age 20. (2) The serum HDLc levels and HDLc/total cholesterol ratio varied with age and sex among healthy subjects. The mean values of HDLc for people over 30 years of age were 58.7 +/- 11.2 mg/100 ml for males and 62.5 +/- 12.2 mg/100 ml for females. The difference was of statistical significance (P less than 0.01). (3) The mean values of serum HDLc were found to be 40.9 +/- 6.0 mg/100 ml and 40.7 +/- 7.9 mg/100 in male and female neonates respectively. These figures are quite similar to those reported from Western countries and Japan. The serum HDLc level rose steadily with age and such elevation was more marked in females than males before age 30. However, the values became closer at age 60, then began to decrease in both sexes. (4) Serum HDLc levels varied markedly with body weight; they correlated negatively with the weight/height index. (5) No statistically significant relationship was found in Chinese between smoking or drinking and serum HDLc levels. The high level of HDLc seemed a result of environmental factors and is, possibly, related to the lower incidence of coronary heart disease in China.

A cross sectional study of markers of hepatitis B infection in Niue

To determine whether the island of Niue would be a suitable location to evaluate the efficacy of hepatitis B vaccine, the prevalence of hepatitis B infection in the adult population was studied. Sera were collected from 1147 of 1244 residents above the age of 20 years, and tested for the presence of hepatitis B surface antigen (HBsAg) and specific antibody to the surface and core antigens (anti-HBs and anti-HBc) by solid-phase radioimmunoassay (SPRIA). Hepatitis B was found to be hyperendemic; 11.9% of those tested were found to be carriers of HBsAg and an additional 84% had detectable levels of anti-HBs or anti-HBc indicative of current or past infection. In this population HBV infection appears to occur early in life as the peak prevalence of serological markers was found in young adults. The almost universal infection of the population, their high rate of compliance with the study and the relatively high birth rate indicate that Niue would be a suitable location to evaluate methods of preventing hepatitis B infection.

Characterization of a precipitating antigen detected in the serum of patients with viral hepatitis

During a search for the aetiological agent of non-A non-B hepatitis, a precipitating antigen was detected in the sera of some patients during the acute phase of their illness. The antigen was detected by agar gel diffusion using antibody from convalescent sera obtained from patients with non-A non-B hepatitis, and from haemophiliac sera. The antigen was usually detected early in the patient's illness, disappearing as liver function tests returned to normal. In some patients specific antibody appeared during the convalescent phase of the disease. The antigen does not appear to be specific for non-A non-B hepatitis, as it could be detected with similar frequency in patients with hepatitis A or hepatitis B and some patients with other liver disorders. Biochemical and biophysical studies suggest that the antigen is probably an abnormal lipoprotein produced as a result of acute liver damage.

Seroepidemiology of infection with hepatitis B virus in Fiji

A batch of 984 sera obtained from a stratified sample of Melanesians and Indians living in rural and urban areas of Fiji in 1981 were for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc) by solid phase radioimmunoassay. The prevalence of hepatitis B infection (as measured by the sum of HBsAg and anti-HBc frequencies of HBsAg negative sera in the two groups) was 81.5% and 17.9%, respectively. No major differences were detected between urban and rural populations. While hepatitis B virus is endemic in Melanesians and Indians, the epidemiology of the infection shows certain differences. Among Melanesians, infection appears to be acquired early in life and peak prevalence of serologic markers of infection occurs during the second decade. Among the Indian population, the prevalence of markers increases steadily with age, presumably as a result of continuous exposure and infection throughout life. the high prevalence of infection and carriers among Melanesians is consistent with previous observations among Pacific populations. The lower prevalence of infection among Indians is remarkable, since they constitute almost half of the total population and live under similar conditions. Since the two populations remain largely separate in terms of housing and schooling, and intermarriage is uncommon, it is no possible to determine whether these differences merely represent different degrees of exposure to the virus or are the reflection of differences in susceptibility or response to infection.

Serum immunoglobulin levels in acute A, B, and non-A, non-B hepatitis

Immunoglobulin M, G, and A concentrations were determined by radial immunodiffusion in sera collected from 117 patients with acute hepatitis A, hepatitis B, or non-A, non-B hepatitis. Statistically significant differences in IgG and IgM levels were detected between the three groups. In particular, elevated IgG and almost-normal IgM levels were regularly detected in patients with non-A, non-B hepatitis while the opposite pattern was seen in patients with hepatitis A. Calculation of a serum IgG/IgM ratio enabled discrimination between most patients with non-B hepatitis. In 92% of patients with hepatitis A, the ratio was less than 6, whereas 82% of patients with non-A, non-B hepatitis had ratios of greater than 6. The IgG/IgM ratio may be of value in distinguishing between subjects with the two forms of the disease when specific serologic tests are unavailable.

Detection of markers of hepatitis B infection in serum dried on to filter-paper: an application to field studies

In an attempt to find a cheap, reliable, and convenient method for the transportation and storage of serum specimens during seroepidemiological surveys, a technique in which serum was dried on to pieces of filter paper was developed and evaluated. For the evaluation, a total of 382 sera were selected from the extensive serum collection held by the WHO Collaborating Centre for Virus Reference and Research at Fairfield Hospital, Australia. These sera were dried on to pieces of filter-paper, stored at different temperatures and then tested for the presence of the various markers of infection with hepatitis B virus by solid-phase radioimmunoassay. The results were in complete agreement with those obtained on whole serum specimens. In addition, storage at 4 degrees C, room temperature (22 degrees C), or 37 degrees C for up to 30 days did not alter the sensitivity of the test. This technique may be useful in field surveys, not only for the detection of hepatitis B infection, but also in the study of other diseases and metabolic disorders.