| expression and characterization of recombinant hepatitis a virus 3c proteinase. | the 3c proteinase from the hepatitis a virus (hav) was cloned into a multicopy expression vector in escherichia coli under control of the tac promoter. the resulting plasmid construction produced 3c proteinase as a soluble and active enzyme constituting approximately 10% of total cellular proteins. the enzyme was purified to apparent homogeneity as judged by sds gel electrophoresis and hplc reversed-phase and fplc ion-exchange chromatography. a colorimetric assay was developed, and synthetic pep ... | 1992 | 1313294 |
| development of live attenuated hepatitis a vaccine (h2-strain). | | 1992 | 1327667 |
| persistent rubella-specific igm reactivity in the absence of recent primary rubella and rubella reinfection. | between two and seven sera from cases of persistent detection of rubella-specific igm for periods in excess of 2.5 months, but in the absence of recent primary rubella or rubella reinfection, were examined for rheumatoid factor, heterophile antibody, and igm reactivity against toxoplasma and a number of viruses. the relative avidity of the rubella-specific igg1 has been assessed in all the sera by two methods. none of the sera contained rheumatoid factor or heterophile antibody, nor did any cont ... | 1992 | 1314284 |
| survival of hepatitis a virus on human hands and its transfer on contact with animate and inanimate surfaces. | the survival of hepatitis a virus (hav; strain hm175) on the hands of five volunteers was determined by depositing 10 microliters of fecally suspended virus on each fingerpad and eluting the inoculum after 0, 20, 60, 120, 180, and 240 min. the amount of virus recovered from each fingerpad at 0 min was approximately 6.0 x 10(4) pfu. at the end of 4 h, 16 to 30% of the initially recoverable virus remained detectable on the fingerpads. hav inocula (10 microliters; approximately 1.0 x 10(4) pfu) pla ... | 1992 | 1315331 |
| clinical trial of a lyophilized inactivated hepatitis a candidate vaccine in healthy adult volunteers. | the safety and immunogenicity of a lyophilized inactivated hepatitis a vaccine was tested in healthy adult male volunteers. thirty-six volunteers, all of whom were negative for antibody to hav (anti-hav), were divided into three dosage groups, 1.0, 0.5 and 0.25 micrograms of viral protein, respectively. each group received a total course of three intramuscular injections at months 0, 1 and 6. slight side effects were noted after 16 of 99 injections and the occurrence and degree were almost ident ... | 1992 | 1315469 |
| [study on diagnosis of hepatitis a by testing salivary igm anti-hav]. | the use of salivary samples to diagnose acute hepatitis a was investigated. result indicated that igm anti-hav can be reliably detected in saliva of 58 cases with acute hepatitis a and 9 cases with mixed infection of hepatitis a and b. it is not present in saliva of individuals without recent hepatitis a including 84 cases with acute hepatitis b, 30 cases of hepatitis non a non b and 10 healthy individuals. it was suggested that use of salivary samples to diagnose hepatitis a was specific. it's ... | 1992 | 1316237 |
| clinical evaluation of oral fluid samples for diagnosis of viral hepatitis. | oral fluid samples were compared with serum samples as a specimen source for hepatitis a, b, and c virus markers. oral fluid was obtained with a treated absorbent pad and tested by using existing commercial enzyme immunoassays with only minor modifications. compared with serum sampling the sensitivity and specificity of oral sampling were 100% (51 of 51 samples) and 98% (46 of 47 samples) for hepatitis a virus immunoglobulin m, 100% (29 of 29 samples) and 100% (29 of 29 samples) for hepatitis b ... | 1992 | 1316364 |
| characterization of a genetic variant of human hepatitis a virus. | human isolates of hepatitis a (hav) are a single serotype; however, recent genetic surveys using limited nucleotide sequencing have provided evidence that more than one genotype is responsible for hav infection in different parts of the world (jansen et al. [1990]: proc natl acad sci usa 87:2867-2871; robertson et al. [1991] j infect dis 163:286-292). one of these genotypes was originally isolated from panamanian owl monkeys (strain pa21), but has subsequently been found associated with human ca ... | 1992 | 1316423 |
| inactivated hepatitis a virus vaccines. | | 1992 | 1317341 |
| time course of hepatitis a virus antibody titer after active and passive immunization. | to investigate the antibody titer necessary to prevent hepatitis a virus infection, either 15 or 7.5 mg/kg of immune serum globulin was injected into 10 antihepatitis a virus negative volunteers and their serum antihepatitis a virus titers were observed for 28 wk. in addition, antibody titers were observed for 96 wk in a phase 1 clinical trial of a hepatitis a vaccine. the two studies were then compared to assess the immunogenicity of the vaccine and the persistence of the antibody. serum-neutra ... | 1992 | 1317343 |
| [improvement of the method of gathering of hepatitis a viruses and its evaluation by water analysis]. | | 1992 | 1330833 |
| assessment of inactivation of hepatitis a vaccine by compound pcr. | assuring the complete inactivation of hepatitis a virus (hav) vaccine commonly requires prolonged tissue culture amplification, followed by detection of virus antigen in cell lysates. a reliable, but faster, alternative procedure is highly desirable since it will permit the prescreening of experimental batches of killed hav, prior to tissue-culture amplification. we established experimental conditions for simultaneous, polymerase chain reaction (pcr)-based amplification of viral and cellular mrn ... | 1992 | 1331145 |
| the role of herd immunity in an epidemic cycle of hepatitis a. | an epidemic of hepatitis a took place in northern ireland between 1984 and 1990. all ages of persons and geographical areas were involved. children aged 5-14 years with belfast addresses were particularly affected. serologically confirmed cases in this group rose from five cases in 1984 to 93 cases in 1987 and fell to 19 cases in 1990. of 100 samples of serum of belfast children aged 5-14 years in late 1985, 23 were hepatitis a igg positive, 95% confidence limits being 15.2-32.5. of 100 similar ... | 1992 | 1318342 |
| clinical trial with inactivated hepatitis a vaccine and recommendations for its use. | to compare the reactogenicity and immunogenicity of an inactivated hepatitis a vaccine in two different immunisation schedules. | 1992 | 1318765 |
| accumulation and persistence of hepatitis a virus in mussels. | accumulation and persistence of hepatitis a virus (hav) in the mussel mytilus chilensis was evaluated. under optimal filtration activity of mussels (temperature 12 degrees c, salinity 3%, feeding twice a day with dunaliella marina), hav was concentrated 100-fold from the surrounding water. similar concentrations of hav were reached in the filtration apparatus and in the digestive system (hepatopancreas). hav persisted for about 7 days in mussels. elimination of hav from mussels was slower than e ... | 1992 | 1331305 |
| genetic relatedness of hepatitis a virus strains recovered from different geographical regions. | a pairwise comparison of the nucleic acid sequence of 168 bases from 152 wild-type or unique cell culture-adapted strains of hepatitis a virus (hav) revealed that hav strains can be differentiated genetically into seven unique genotypes (i to vii). in general, the nucleotide sequence of viruses in different genotypes differs at 15 to 25% of positions within this segment of the genome. viruses from four of the genotypes (i, ii, iii and vii) were recovered from cases of hepatitis a in humans, wher ... | 1992 | 1318940 |
| prevalence of antibodies to hepatitis viruses in blood donors with a clinical history of hepatitis. | a comparison between the 1979, 1982 and 1989 findings indicates that the number of adults susceptible to hav infections has increased. this fact should be given attention in view of the strongly altered travelling pattern of fairly large sections of the population. it should also be kept in mind that the group of adults born between 1951 and 1960 comprises those adults who have the most frequent contacts with younger children being at the greatest risk of acquiring hav infection. | 1992 | 1319249 |
| recommendations for use of hepatitis a vaccine. | | 1992 | 1320975 |
| myelopoiesis in vitro is suppressed by hepatitis a virus. | perturbations of hematopoietic regulation ranging from transient granulocytopenia to rare cases of bone marrow failure are associated with infections due to hepatitis a virus (hav). in an attempt to elucidate the pathogenetic mechanisms we had previously established that hav has a direct suppressive effect on human bone marrow progenitors (cfu-gm, -gemm, bfu-e). these studies were extended to long-term bone marrow cultures (ltbmc): inoculation of bone marrow mononuclear cells with hav did not in ... | 1992 | 1322183 |
| [virus persistence in hepatitis a in monkeys]. | a long-term complex observation of 16 cynomolgus monkeys (macaca fascicularis) and 8 african green monkeys (cercopithecus aethiops) with spontaneous and experimental hepatitis a revealed two forms of the illness: acute and chronic. some monkeys developed undulating chronic course of the disease consisting of 2-6 waves. others developed relapses (1 to 3) which occurred within 2-4 or 6-11.5 months of the infection. the morphological changes in the liver persisted for 7-28 months. alaninaminotransf ... | 1992 | 1332264 |
| [viral hepatitis a and b]. | | 1992 | 1332266 |
| hepatitis a vaccination--an option for south africa? | | 1992 | 1322563 |
| evolution of hepatitis a antibodies prevalence in young french military recruits. | hepatitis a antibodies (anti-hav) were surveyed in 1000 french recruits during 1990. the prevalence of anti-hav in this group was 21.35%. compared to a 1985 survey a 9% fall in the anti-hav prevalence rate was observed. living in a coastal area, low educational level, stay overseas were the main risk factors, as already noted in 1985. | 1992 | 1322824 |
| salivary antibody testing in a school outbreak of hepatitis a. | during a community-wide outbreak of hepatitis a in gloucester, uk there was a high attack rate in children attending two city primary schools and a pre-school centre sharing the same site. in september 1990, saliva specimens were collected from 478 (85%) of the 562 children. the prevalence of antibody to hepatitis a virus (anti-hav), as determined by saliva testing, was 29.6%; highest prevalences were seen in 5-6-year-olds and in children from that area of the city at the centre of the community ... | 1992 | 1323482 |
| multistate outbreak of hepatitis a associated with frozen strawberries. | a multistate outbreak of hepatitis a was traced to frozen strawberries processed at a single plant. among 827 students and 60 teachers at an elementary school in georgia during a 2-week period, 15 developed hepatitis a. three months later, among 174 residents and 467 staff in an institution for the developmentally disabled in montana during a 3-week period, 13 developed hepatitis a. primary attack rates were 10% in the school and 8% in the institution. cohort analysis in the school implicated co ... | 1992 | 1323618 |
| polyprotein processing in cis and in trans by hepatitis a virus 3c protease cloned and expressed in escherichia coli. | to determine the p3 region protein-processing sites cleaved by the hepatitis a virus 3c protease, a nested set of constructs containing a portion of 3a (3a* [the asterisk denotes an incomplete protein]), 3b and 3c and various amounts of 3d, fused in frame to escherichia coli trpe-coding sequences under control of the tryptophan promoter, was made. additional plasmids that encoded a portion of 2c (2c*) and the p3 proteins, including complete or incomplete 3d sequences, were constructed. after ind ... | 1992 | 1323691 |
| in situ hybridization studies in hepatitis a infection. | an in situ hybridization method using radiolabeled oligonucleotide probes was developed to study primary sites of hepatitis a virus replication in an experimental animal model of infection. hepatitis a genomic sequences were demonstrated in hepatocytes of four marmosets with acute hepatitis a by use of antisense probes. in two of these animals, staining was also found when a sense probe was used, which is consistent with active replication in the hepatocytes. the specificity of the hybridization ... | 1992 | 1324214 |
| prevalence of markers of hepatotropic viruses among drug addicts in warsaw, poland. | we studied 100 unselected parenteral drug abusers for infection with hepatitis c, b, a and d virus (hcv, hbv, hav and hdv). seventy-six percent had serological evidence of hcv infection. 12% were positive for hbsag and at least one marker of hbv infection was present in 69%. these results were significantly higher than in a matched control population. compared to controls, the prevalence of anti-hav (65%) was not significantly increased in drug addicts. of the anti-hcv-positive drug addicts, 80. ... | 1992 | 1324268 |
| [spontaneous and experimental hepatitis a in papio hamadryas]. | data on high susceptibility of papio hamadryas to hav are presented. for the first time, p. hamadryas were shown to be able to respond to both natural and experimental infection developing the features typical of hepatitis a: increased aminotransferase activity, virus shedding in feces, production of anti-hav igg and igm, histological liver lesions. an infection lingering for 3-4 months was observed, as well as a case of chronic experimental hepatitis a with relapse in 7 months of the disease. v ... | 1992 | 1335190 |
| [status of collective immunity to hepatitis a virus in urban residents in byelorussia]. | the large immune stratum and intense collective immunity to virus hepatitis a among the urban population of byelorussia are characteristic of hyperendemic territory. the geometric mean of the antibody titer has been noted to increase with age, which is probably due to repeated infections of persons who have already had the disease. the use of this value for the characterization of collective immunity and epidemiological situation has been proposed. | 1992 | 1324550 |
| [the status of hepatitis a vaccination 1992]. | | 1992 | 1326782 |
| [the etiological structure and epidemiological characteristics of viral hepatitis among servicemen]. | selected studies on etiological structure of hepatitis a were conducted among servicemen, using modern high-sensitive orrhological methods of diagnosis. 325 serums obtained from infectious patients were examined in the laboratory. on the basis of this analysis the authors make a conclusion concerning a rather high level of fecal-oral viral hepatitis among servicemen of the 40th army, which differed from hepatitis a. | 1992 | 1326824 |
| hepatitis a--new information on an old virus. | | 1992 | 1328008 |
| intermolecular cleavage of hepatitis a virus (hav) precursor protein p1-p2 by recombinant hav proteinase 3c. | active proteinase 3c of hepatitis a virus (hav) was expressed in bacteria either as a mature enzyme or as a protein fused to the entire polymerase 3d or to a part of it, and their identities were shown by immunoblot analysis. intermolecular cleavage activity was demonstrated by incubating in vitro-translated and radiolabeled hav precursor protein p1-p2 with extracts of bacteria transformed with plasmids containing recombinant hav 3c. identification of cleavage products p1, vp1, and vpo-vp3 by im ... | 1992 | 1328690 |
| [hepatitis a outbreak in a kindergarten]. | in november/december 1990 eight out of 38 children of a kindergarten in basle were involved in an outbreak of hepatitis a, and further cases occurred among family members and friends of the children. a questionnaire survey and a serologic analysis including all families associated with the kindergarten was undertaken to investigate the source, extent and spread of the hepatitis a. among 147 persons examined, 20 clinical cases of hepatitis a were diagnosed (9 adults, 11 children), 5 more children ... | 1992 | 1329190 |
| [the biochemical indices of the blood serum in experimental hepatitis a in tamarins]. | serum biochemical parameters were studied in 42 healthy wild-caught adult tamarins (s. mystax), males and females, to determine the normal values. blood samples were drawn repeatedly, and the serum was tested for aspartate aminotransferase, alanine aminotransferase, isocitric dehydrogenase, serum glucose, serum urea, triglyceride, cholesterol, albumin, and total protein. the results indicated that serum chemistry values were similar to those reported as normal for both humans and other callitric ... | 1992 | 1329356 |
| hepatitis a vaccine. | | 1992 | 1330143 |
| [family-acquired hepatitis a--prevalence of hepatitis a among the family in aichi prefecture, 1990]. | we studied the transmission of hepatitis a virus (hav) in 45 families, which members were diagnosed as hepatitis a in 8 hospitals in 1990. feces and sera from 50 patients and their 126 family members were tested for hav-specific antigen and igm antibody by elisa or polymerase chain reaction (pcr) technology. from the interval of the onset of hepatitis or detection of hav antigen in feces, hav transmission was recognized in 11 (24.4%) of 45 families. the transmission was found to be concerned wit ... | 1992 | 1331263 |
| [practical remarks regarding the analysis of markers of acute viral hepatitis]. | | 1992 | 1332002 |
| a cis-acting element within the hepatitis a virus 5'-non-coding region required for in vitro translation. | every picornavirus studied thus far has a sequence within the 5'-non-coding region that is required for internal ribosome binding and translation of the polyprotein. in an attempt to identify this region in hepatitis a virus we constructed a truncated hepatitis a virus (hav) cdna clone that contains the entire 736 bp 5' non-coding region (5'-ncr) and 754 base pairs of the viral capsid coding region (p1) under control of the sp6 promoter. in vitro transcription and translation of this transcript ... | 1992 | 1332279 |
| in situ hybridization in viral hepatitis. | in situ hybridization (ish) is a sensitive and specific technique for detecting nucleic acids in intact cells. visualization of the target sequences by autoradiography or immunohistochemistry allows their precise subcellular localization and quantitation. the application of ish techniques has contributed to the understanding of the complex replicative cycle of hepatitis b virus. more recently, hepatitis delta and c virus replication has also been studied by this technique. ish-based assays have ... | 1992 | 1333029 |
| [a comprehensive approach to the analysis of cytoimmunological indices in patients with viral hepatitis a and b]. | | 1992 | 1333140 |
| [liver cancer and hepatitis b and c virus]. | chronic infection by hepatitis b and c viruses is frequently associated to the development of primary liver cancer. liver cirrhosis, induced by these viral infection, plays an important role in the liver carcinogenesis. in addition, hbv has a direct role in liver cell transformation by a transactivating effect of some viral proteins as well as insertional mutagenesis. the role of hepatitis c virus is not known. the strong association, even in france, of primary liver cancer to these viral infect ... | 1992 | 1333632 |
| immunogenicity of inactivated purified tissue culture vaccine against hepatitis a (hepavac) assessed in laboratory rodents. | immune response of laboratory rodents (guinea-pigs, cba and balb/c mice, wistar and august rats) to inactivated hepatitis a vaccine was quantitatively assessed. under comparable conditions of experiment, the mice showed the highest antibody titres and were capable of reacting to the lower doses of immunogen; meanwhile their individual variations in immune response were more pronounced; white rats were the least susceptible to the vaccine, demonstrating the minimal antibody formation; guinea-pigs ... | 1992 | 1333687 |
| [the circulation of the hepatitis a and b viruses in the somali population]. | we report the results of a study carried out to evaluate the extent of hepatitis a virus (hav) and hepatitis b virus (hbv) circulation in somalia. serum samples were collected from 593 subjects (age range 0-83 years) and tested for anti-hepatitis a (hav) and anti-hav igm. serum samples taken from 1272 individuals (age range 0-83 years) were tested for hbsag, anti-hbsag, anti-hbcag, hbeag and anti-hbeag. we confirmed a very high rate of hav exposure (about 90% of the subjects tested had circulati ... | 1992 | 1334688 |
| immunopotentiating reconstituted influenza virus virosome vaccine delivery system for immunization against hepatitis a. | hepatitis a virus (hav) was purified from mrc-5 human diploid cell cultures, inactivated with formalin, and evaluated for safety and immunogenicity in humans. three vaccine formulations were produced: (a) a fluid preparation containing inactivated hav, (b) inactivated hav adsorbed to al(oh)3, and (c) inactivated hav coupled to novel immunopotentiating reconstituted influenza virosomes (iriv). iriv were prepared by combining phosphatidylcholine, phosphatidylethanolamine, phospholipids originating ... | 1992 | 1334977 |
| cdna clone of hepatitis a virus encoding a virulent virus: induction of viral hepatitis by direct nucleic acid transfection of marmosets. | direct inoculation of marmoset livers with an in vitro transcription mixture containing cdna and full-length genomic rna transcripts of hepatitis a virus resulted in acute viral hepatitis. elevations in serum levels of liver enzymes were correlated with appearance of antibody to hepatitis a virus. genomes of infectious hepatitis a virus isolated from the feces of transfected marmosets contained the same mutation as the cdna template used for transfection. liver biopsies confirmed that the virus ... | 1992 | 1328684 |
| [the role of the food transmission factor in the occurrence of 2 hepatitis a outbreaks]. | two outbreaks of virus hepatitis were etiologically and epidemiologically interpreted. in this work the original method of obtaining washings, with their subsequent concentration, from the suspected foodstuff was used and hepatitis a virus was then detected in concentrated washings in the enzyme immunoassay, which made it possible to confirm the contribution of the alimentary factor of the transfer of infection (sun-cured melon) in the above-mentioned outbreaks. the data thus obtained are indica ... | 1992 | 1329408 |
| [isolation of hav from sea clam]. | three strains of hav were isolated directly from clams (arca subcrensta lisckke) collected from sea with cell culture and identified by electron microscopy, immunofluorescent test, elisa, hav-cdna hybridization and neutralization test. the strains were stably passed in 2bs cells with the titer of 4.0-5.0 tcid50/ml. results indicated that the clams were contaminated by hav and may cause an outbreak of hepatitis a. | 1992 | 1330317 |
| [evaluation of micro particle enzyme immunoassay technique (meia)-imx for the detection of antibody to hepatitis a virus]. | a new micro particle enzyme immunoassay technique (meia, imx havab, abbott) has been recently introduced for the detection of antibody to hepatitis a virus (anti-ha). to evaluate the feasibility of the imx havab, we carried out comparison tests between meia, ria and eia. furthermore, we investigated the prevalence of anti-ha in fukuoka city and yonaguni island, okinawa, japan using this method. results obtained were as follows: in the test of 514 sera, 254 (49.0%) were positive by the three meth ... | 1992 | 1331266 |
| identification of precursors of structural proteins vp1 and vp2 of hepatitis a virus. | the morphogenetic pathway of hepatitis a virus (hav), classified as a member of the enteroviruses within the picornaviridae, still remains obscure and seems to differ considerably from that of poliovirus, the most studied representative of this genus. in order to elucidate the precursor/product relationship of hav structural proteins, subviral particles, which represent more than 50% of the viral antigen produced in infected cells, were separated from mature virions and their polypeptide pattern ... | 1992 | 1331311 |
| [apparent simultaneous occurrence of hepatitis a and hepatitis b infections]. | in this study, 92 patients sera which were found to be hbsag positive by elisa method were investigated for hepatitis a. in this study anti-hav igm antibody was investigated to determine acute cases. anti-hav igm was found to be positive in 3 (3.2%) of 92 patients sera whose hbsag were positive. | 1992 | 1331719 |
| a vaccine against hepatitis a--at last. | | 1992 | 1331725 |
| serological approaches to distinguish immune response to hepatitis a vaccine and natural infection. | currently, the immune status of an individual exposed to hepatitis a virus (hav) is determined by assays which measure antibodies against the capsid proteins. these assays indicate exposure to the viral capsid that could result from either infection or from vaccination. recent data indicate that proteins from the non-structural genome region of the virus (p2 or p3), which are only produced during active virus replication, generate antibodies after clinical disease. a sub-genomic cdna segment of ... | 1992 | 1335637 |
| effect of virus strain and antigen dose on immunogenicity and reactogenicity of an inactivated hepatitis a vaccine. | a randomized double-blind comparison of five killed hepatitis a vaccine preparations was carried out with eligible medical student and staff volunteers. vaccines were prepared in m rc-5 cells and formalin-inactivated. three monthly injections of 1 ml in the deltoid muscle were given. group a received the clf strain at a dose of 360 elisa units (el.u) in 0.5 mg aluminium hydroxide (n = 35). the other groups received the hm175 strain as follows: 180 el.u in 1 mg aluminium hydroxide (to group b, n ... | 1992 | 1335638 |
| inactivated hepatitis a vaccine: a safety and immunogenicity study in health professionals. | the safety and immunogenicity of an inactivated hepatitis a vaccine (hm175 strain) were evaluated in 150 seronegative health professionals. the age range was 21-65 years and the mean age was 30 years. the vaccine was administered at a dose of 720 elisa units (eu) to 73 vaccinees at 0, 1 and 6 months, and to 77 vaccinees at 0, 1 and 12 months. the seroconversion rates were 88 and 90% in the two groups, respectively, one month after the first inoculation and 99 and 100% one month after the second ... | 1992 | 1335639 |
| effect of hepatitis a vaccination schedules on immune response. | an inactivated hepatitis a vaccine was given to 104 seronegative volunteers aged between 19 and 60 years according to two schedules: 0, 1 and 2 months or 0, 1 and 6 months. the vaccine was well tolerated and 97 and 100% of vaccinees developed a serum antibody response following a single and two doses of vaccine respectively. geometric mean titres increased progressively after each dose; responses following the 0, 1, 6 month schedule were significantly higher at one year but, among those tested a ... | 1992 | 1335640 |
| hepatitis a vaccination: schedule for accelerated immunization. | hepatitis a vaccine, strain hm175, was investigated for immunogenicity and tolerability in a prospective multicentre trial. the following vaccination schedules and antigen contents were evaluated: days 0 and 14 with 720 elisa units (el.u) of antigen, days 0 and 28 with 720 el.u and days 0 and 28 with 360 el.u. in all study groups, the seroconversion rates following two vaccinations were between 95 and 100%. higher geometric mean concentrations of antibody to hepatitis a virus (anti-hav) were rea ... | 1992 | 1335641 |
| clinical and laboratory observations following oral or intramuscular administration of a live attenuated hepatitis a vaccine candidate. | clinical observations made after immunising volunteers with a live attenuated hepatitis a vaccine are described. the candidate vaccine was prepared with the hm175 strain of hepatitis a virus and shown to be safe, immunogenic and efficacious in experimental animals. when the candidate vaccine was tested by oral administration in humans at increasing doses--10(4), 10(5), 10(6) and 10(7) median tissue culture infective doses (tcid50)--an antibody response was not observed at any dose. volunteers wh ... | 1992 | 1335645 |
| prevention of viral hepatitis a: past, present and future. | before hepatitis a virus (hav) was identified, spread of hepatitis a was prevented by public health measures. the first specific, preventive measure for hepatitis a was passive protection with standard, pooled human immune globulins. human immune globulin contained sufficient hav neutralizing antibodies for short-term, prophylactic passive protection and for control of the spread of local outbreaks. after many unsuccessful attempts, hav was propagated in cell cultures and the development of vacc ... | 1992 | 1335635 |
| laboratory tests and reference reagents employed in studies of inactivated hepatitis a vaccine. | procedures to evaluate inactivated hepatitis a vaccines in volunteers have been examined. solid-phase immunoassays were standardized with reference preparations and have been tested to measure antibody response to immunization and antigen content of vaccines. following immunization, there was a good correlation between antibody response, determined with commercial immunoassays, and neutralization titres, as measured by the radioimmunofocus inhibition test. however, at lower titres of neutralizin ... | 1992 | 1335636 |
| vaccination against hepatitis a: comparison of different short-term immunization schedules. | a total of 114 healthy young adults were immunized with hepatitis a vaccine using different vaccination schedules. individuals received either a single dose (group 1), two doses given simultaneously (group 2), two doses at days 0 and 14 (group 3) or at days 0 and 28 (group 4), or three doses at days 0, 7 and 21 (group 5). two weeks after a single dose, seroconversion rates between 77 and 85% were achieved (groups 1, 3, 4). all individuals immunized with two doses within two weeks (groups 2, 3, 5 ... | 1992 | 1335642 |
| persistence of vaccine-induced antibody to hepatitis a virus. | a level of 10 miu hepatitis a antibodies/ml as measured by elisa is believed to be the minimal protective concentration. if this level is considered, the mean persistence of vaccine induced antibodies is approximately 10-11 years after booster dose, 6-7 years if only the primary doses are given and 5-6 years if the minimal individual titre is taken into account. | 1992 | 1335643 |
| reactogenicity and immunogenicity of three different lots of a hepatitis a vaccine. | to study the immunogenicity and reactogenicity of an inactivated hepatitis a vaccine, 204 healthy individuals were randomized into three equal groups, each to receive a different vaccine lot. each subject received a total of three doses, each of 720 elisa units of hepatitis a vaccine hm175, according to a 0 and 1 month primary vaccination schedule, with a booster dose given at month 6. side effects were low and were < 30% after the second injection. all subjects but one had antibodies to hepatit ... | 1992 | 1335644 |
| placebo-controlled efficacy study of hepatitis a vaccine in valdivia, chile. | a placebo-controlled, double-blind study on the efficacy of a hepatitis a vaccine (smithkline beecham biologicals) was started in a region of chile in september 1990, using hepatitis b vaccine as control. a total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis a virus (anti-hav), antibody to hav immunoglobulin m (igm), hepatitis b surface antigen, and antibody to hepatitis b surface and core antigens by elisa tests within 7 days before vaccination, were randomly as ... | 1992 | 1335650 |
| field evaluation of a hepatitis a vaccine in a norwegian contingent to the united nations interim force in lebanon. | the norwegian population is basically seronegative regarding anti-hepatitis a antibodies. for this reason they are particularly vulnerable when exposed to hepatitis a virus when staying in highly endemic areas. norwegian un-personnel have so far been protected with serum immunoglobulins (ig). two studies are reported, one followed a vaccination schedule of 0, 1 and 2 months with a booster at month 12, while the other followed a schedule of day 0 and 14 with a booster at month 7. both were field ... | 1992 | 1335651 |
| hepatitis a in the us army: epidemiology and vaccine development. | control of hepatitis a has been an important concern for us military forces in war and peace. immune serum globulin, although effective, is exceedingly cumbersome to use. the prevalence of antibody against hepatitis a is decreasing in young american soldiers, putting them at risk of hepatitis a during deployment. the us army has been an active participant in development of hepatitis a vaccine. the first successful cell-culture-derived, formalin-inactivated hepatitis a vaccine was developed at th ... | 1992 | 1335665 |
| simultaneous passive and active immunization against hepatitis a. | the serum antibody response to simultaneous administration of immune globulin (ig) and an inactivated hepatitis a vaccine was investigated in healthy volunteers who had been tested and found free of hepatitis a virus. one hundred and forty nine subjects were randomly allocated into three groups. group 1 received three doses of hepatitis a vaccine at 0, 1 and 6 months, group 2 received 5 ml of ig and group 3 received a combination of ig and vaccine. in group 3 the seropositivity rate measured by ... | 1992 | 1335646 |
| simultaneous vaccination against hepatitis a and b: results of a controlled study. | hepatitis a and hepatitis b are endemic in many countries and must be considered as serious health risks for large parts of the world population. simultaneous or combined vaccination against these two diseases would therefore be most advantageous. in order to investigate possible interactions between these vaccines with respect to their tolerability and immunogenicity, we conducted a randomized prospective study comparing single and simultaneous administration of the two vaccines. three groups o ... | 1992 | 1335647 |
| production, quality control and characterization of an inactivated hepatitis a vaccine. | the isolation and adaptation of hepatitis a virus to cell culture opened the way to the development of vaccines. based on experience with inactivated poliovaccines, a similar approach was chosen for the development of an inactivated hepatitis a vaccine. strain hm175, adapted to mrc-5 human diploid cells, was used as the virus strain. vaccine production starts with growth and multiplication of the seed virus in mrc-5 cells. the harvests are clarified, purified and concentrated. inactivation by fo ... | 1992 | 1335671 |
| why do human hepatitis viruses replicate so poorly in cell cultures? | the five viruses which classically cause hepatitis in man represent diverse families of viruses and share in common only a striking hepatotropism and substantial restrictions to replication in conventional cell cultures. hepatitis a virus is unique among these viruses in that it is amenable to propagation in cell culture, but replication of this virus is much slower and less efficient than replication of other picornaviruses. this probably reflects less efficient cap-independent viral translatio ... | 1992 | 1335949 |
| comparison of modified havab and elisa for determination of vaccine-induced anti-hav response. | an inhibition elisa was compared with a modification of the havab assay for measuring antibodies induced by a killed hav vaccine. gmt's expressed in miu/ml were higher by elisa than by modified havab, especially after the first and second doses of vaccine but seroconversion rates were very similar and a good correlation was found between both assays. because of its higher sensitivity and specificity, the elisa assay was preferred to modified havab for the evaluation of a hepatitis a vaccine in h ... | 1992 | 1339039 |
| clinical assessment of the safety and efficacy of an inactivated hepatitis a vaccine: rationale and summary of findings. | the objectives for the clinical testing of the inactivated hepatitis a vaccine developed by smithkline beecham biologicals are reviewed and the results obtained are summarized. the first studies were carried out in healthy young adult volunteers using pilot vaccine lots prepared from the clf and hm175 strains of hepatitis a virus (hav). it was established that the candidate vaccines were well-tolerated, caused no hypersensitivity reactions and elicited a strong antibody response. as the yield in ... | 1992 | 1335652 |
| hepatitis a as an occupational hazard. | few studies have been carried out to evaluate the role of hepatitis a virus (hav) as an occupational hazard. our analysis of data on occupational diseases in germany showed that hepatitis a ranks as third among infectious occupational diseases. morbidity based on the frequency of compensation (15.2%) was in the same range as that observed for hepatitis b (19.7%). in another study, data were collected on anti-hav prevalence among 2293 hospital workers in southwest germany. anti-hav prevalence of ... | 1992 | 1335666 |
| who should receive hepatitis a vaccine? considerations for the development of an immunization strategy. | the availability of efficacious hepatitis a vaccines should greatly facilitate the prevention of hepatitis a virus (hav) infection. groups at high risk of hav infection have been identified from epidemiological studies and include both children and adults. while certain high-risk adults, such as travellers, could be a convenient target for vaccination, selective immunization of high-risk adults would not be expected to lower the overall rates of infection in most countries. because a significant ... | 1992 | 1335667 |
| a brazilian hepatitis a virus isolated and adapted in primate and primate cell line as a chance for the development of a vaccine. | | 1992 | 1343657 |
| epidemiological patterns of hepatitis a in different parts of the world. | serological surveys in many communities show a high prevalence of antibodies to hepatitis a virus (hav) in people over the age of 50 years. however, few of that age can recall a previous episode of hepatitis, indicating that subclinical infections are common. the outcome of infection with hav depends on the age at which infection occurs and, perhaps, the infectious dose. fulminant disease is well recorded, with the frequency varying from one to eight per 1000 cases. information on the frequency ... | 1992 | 1335660 |
| international symposium on active immunization against hepatitis a. vienna, 27-29 january 1992. | | 1992 | 1335661 |
| properties and classification of hepatitis a virus. | hepatitis a virus (hav) is a member of the picornavirus family. it was first provisionally classified as enterovirus 72, but subsequent determinations of its nucleotide and amino acid sequences showed them to be sufficiently distinct to assign the virus to a new genus. heparna-virus (hep-a-rna-virus) has been suggested as the genus name. hav shares the key properties of the picornavirus family: an icosahedral particle 28 nm in diameter with cubic symmetry, composed of 30% rna and 70% protein. th ... | 1992 | 1335653 |
| cost-effectiveness analysis of hepatitis a prevention in travellers. | the advent of new vaccines and the changing epidemiology of hepatitis a call for an update of the economic evaluation of costs and benefits associated with the various alternative preventative strategies. a decision-tree-based model has been developed which enables the calculation of expected costs and expected numbers of hepatitis a virus hav infections based on different intervention strategies. the model is sufficiently generic to allow for the evaluation of both population-wide strategies an ... | 1992 | 1335668 |
| natural hosts of hepatitis a virus. | the host range for hepatitis a virus (hav) is limited to man and several species of non-human primates, and involvement of vertebrates other than primates in hav circulation is unlikely. spontaneous hepatitis a infection has been reported to occur in captive non-human primates including the great apes (chimpanzee) as well as old world (cynomolgus, african vervet, stump-tailed) and new world (aotus) monkeys. the presence of anti-hav antibody in the sera of newly captured monkeys of these species ... | 1992 | 1335654 |
| how an outbreak of hepatitis a in melbourne led to the development of a vaccine. | | 1992 | 1335669 |
| replication of hepatitis a virus and processing of proteins. | isolation and propagation of hepatitis a virus (hav) in cell culture is routinely possible. all primary hav isolates and most established virus strains, however, show a protracted replication behaviour and tend to establish a persistent infection. rapidly replicating, cytolytic variant viruses can be selected from persistently infected cultures under distinct conditions. factors critical for the outcome of hav infection include the genetics of the virus, the physiological state of the infected c ... | 1992 | 1335655 |
| perspectives on the control of hepatitis a by vaccination. | the availability of an inactivated hepatitis a virus (hav) vaccine, and the development of live attenuated virus vaccines against hepatitis represent great advances in the effort to control an important cause of viral hepatitis. there are a number of ways hepatitis a vaccines could be used, depending on the epidemiology of hav infection in the country concerned, the cost of the product, the duration of protection that the vaccine affords and its effectiveness for postexposure prophylaxis. expert ... | 1992 | 1335670 |
| hepatitis a virus and hepatitis a infection. | | 1991 | 1645494 |
| molecular basis of virulence and growth of hepatitis a virus in cell culture. | the ability of engineering variants of hepatitis a virus (strain hm175) to replicate in cell culture or to cause disease in marmosets was evaluated. virus variants were encoded by chimeric genomes constructed from infectious cdna clones of two viruses (wild type and cell-culture-adapted) which differed in their ability to grow in vitro and to cause acute hepatitis in marmosets. transfection and infectivity assays indicated that virus growth in vitro could be enhanced by subcloning the cell subst ... | 1992 | 1335656 |
| genetic, antigenic and biological differences between strains of hepatitis a virus. | recent studies have documented a considerable degree of genetic divergence among wild-type hepatitis a virus (hav) strains recovered from different geographical locations. human hav strains can be grouped into four genotypes (i, ii, iii and vii) and unique simian strains belong to three additional genotypes (iv, v and vi). between each of these genotypes, the nucleotide sequence varies at 15-25% of base positions in the p1 region. despite this, there is good evidence that most, if not all, human ... | 1992 | 1335657 |
| baseline seroepidemiology of hepatitis a virus infection among children and teenagers in italy. | during the period from may 1987 through november 1989, the prevalence of antibodies to hepatitis a virus infection (anti-hav) was assayed by the elisa method in the serum samples of 5,507 (54% males, 46% females) apparently healthy subjects three to 19 years old in italy. subjects were selected by a systematic cluster sampling in five different geographical areas of italy. the overall prevalence of anti-hav was 9.5%; it increased from 2.3% among children three to five-years-old to 16.3% in teena ... | 1991 | 1646772 |
| passive immunization against hepatitis a. | administration of human serum immune globulin (ig) is an effective means of protecting individuals against hepatitis a virus (hav) infection and disease. several large field studies have demonstrated that if given before exposure, ig will prevent infection with hav. furthermore, if ig is given during the incubation period of hepatitis a, the severity of infection may be reduced and potentially clinical infections may be converted into subclinical ones. although uncommon, infection which occurs i ... | 1992 | 1335658 |
| possible approaches to develop vaccines against hepatitis a. | more than a decade ago, successful replication of hepatitis a virus (hav) in cell culture opened the way to the development of live attenuated and inactivated vaccine candidates. serial passages of hav in cell culture led to attenuation as demonstrated by experiments in non-human primates. several live vaccine candidates obtained through serial passages have been evaluated in volunteers. significant improvements in the yield of viral antigen from infected cell cultures stimulated the development ... | 1992 | 1335659 |
| immunity to hepatitis a in hospital personnel. | | 1992 | 1337894 |
| [use of non-radioactive biotin-labelled probes for detecting hepatitis a virus]. | the biotin-labeled dna probes were constructed on the basis of the hybrid bacteriophage m13nip 9 single-stranded dna containing the fragments of the hepatitis a viral cdna. the probes were biotin treated by chemical modification of the dna by the peraminating reagent or photochemically. the labeled dna probes were used in molecular hybridization experiments with the nuclear acids fixed on the nitrocellulose filters. the biotin treated dna was determined by the avidin-gold colloid conjugate with ... | 1992 | 1338551 |
| inactivated hepatitis a vaccine: active and passive immunoprophylaxis in chimpanzees. | studies of active and passive immunoprophylaxis were carried out in chimpanzees to determine whether a candidate hepatitis a virus (hav) vaccine could stimulate antibody to hav (anti-hav) that was qualitatively similar to anti-hav stimulated by natural infection. normal immune globulin (ig) was prepared from plasma obtained from human volunteers before and after vaccination with the hav vaccine, and these preparations or commercially prepared ig were administered to chimpanzees. protective effic ... | 1992 | 1335648 |
| clinical manifestations and diagnosis of hepatitis a virus infection. | hepatitis a is an acute, necroinflammatory disease of the liver which results from infection by the hepatitis a virus (hav). the mean incubation period is approximately 30 days. although the disease is usually self-limited, the severity of illness is age-dependent. in children, hepatitis a is usually asymptomatic, while in adults, symptomatic infection is characteristic and jaundice is common. fulminant hepatitis a is rare and is also age-dependent. the onset of hepatitis a is often abrupt and c ... | 1992 | 1335649 |
| parameters influencing the attachment of hepatitis a virus to a variety of continuous cell lines. | we have investigated the interactions of purified radiolabelled hepatitis a virus (hav) with a variety of continuous cell lines. virus labelled either in vitro with radiolabelled iodine or in vivo with radiolabelled uridine bound to cells with similar efficiency. attachment to bs-c-1 cells was calcium ion-dependent and this correlated with infectivity assay results. the cell tropism of hav attachment was examined using cell suspensions and confluent cell monolayers at both 4 degrees c and 37 deg ... | 1991 | 1649900 |
| simian hepatitis a virus (hav) strain agm-27: comparison of genome structure and growth in cell culture with other hav strains. | fragments of cdna representing greater than 99% of the entire genome of wild-type hepatitis a virus (hav) strain agm-27, isolated from an african green monkey, were obtained by the polymerase chain reaction and sequenced. comparison with other hav isolates revealed differences in the predicted amino acid sequence in functionally critical parts of the genome. comparison of the biological properties of agm-27 with those of human wild-type and cell culture-adapted hm-175 strains revealed that agm-2 ... | 1991 | 1649901 |
| sequence analysis of a new hepatitis a virus naturally infecting cynomolgus macaques (macaca fascicularis). | a new isolate of hepatitis a virus (hav), cy-145, was isolated from stool specimens obtained from cynomolgus macaques naturally infected with this agent. sequence analysis of the capsid region of the genome indicated that this virus differed from other sequenced hav strains by about 20% at the nucleotide level and 7% at the amino acid level. two amino acid residues (residues 70 of vp3 and 102 of vp1), previously identified as constituting an immunodominant site and conserved in all sequenced hav ... | 1991 | 1649902 |
| epidemiology of hepatitis a in mediterranean countries. | infection with hepatitis a virus (hav) is still endemic in some mediterranean areas. in most northern mediterranean countries, the incidence of acute icteric hepatitis in adults is increasing. this is due to the shifting of hav infection to adulthood as a result of the decline of its overall prevalence due to improvements in socioeconomic, sanitary and hygienic conditions. the majority of adults remain susceptible and develop overt disease when infected, since the severity of disease is highly a ... | 1992 | 1335662 |
| ecology and prevention of a shellfish-associated hepatitis a epidemic in shanghai, china. | during a shellfish-borne hepatitis a outbreak in shanghai during the first quarter of 1988, 300,000 cases were reported in two months. using cell culture and experimental infection of marmosets, hepatitis a virus (hav) was isolated from clams collected from the market and the sea bed during the epidemic. a dose-response curve correlating the quantity of clams consumed to the attack rate of hepatitis a was well documented. the occurrence of the epidemic was associated with a good harvest of clams ... | 1992 | 1335663 |
| risk of hepatitis a in travellers. | a review of the literature shows that 30-35 million travellers from industrialized nations annually visit a developing country where their incidence rate of symptomatic hepatitis a is 3 to 6 per 1000 per month of stay if they remain unprotected. the risk is 20 per 1000 for persons eating and drinking under poor hygienic conditions. thus hepatitis a is now the most frequent vaccine-preventable disease in such travellers. antibodies to hepatitis a virus are rarely found in potential travellers in ... | 1992 | 1335664 |