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J R Wands

Publications and source records attributed to J R Wands.

At least 145 records · Page 8Linked to original sources
PubMed1992

Neuronal thread protein over-expression in brains with Alzheimer's disease lesions.

Neuronal thread protein (NTP) is a recently characterized molecule that is over-expressed in brains with Alzheimer's disease (AD) lesions. The present study encompasses a detailed analysis of NTP expression in AD compared with other neurodegenerative diseases and aged controls. Using a specific monoclonal antibody, NTP immunoreactivity was evaluated in 309 paraffin-embedded sections from 8 different regions of the frontal, parietal, and temporal lobes of 73 brains with AD, AD + Down's syndrome (DN), AD + Parkinson's disease (PD), PD dementia (PDD), aged controls, and disease controls with Huntington's disease, multi-infarct dementia, or schizophrenia. In 250 adjacent blocks of snap-frozen unfixed tissue the concentration of NTP (ng/mg of protein) was measured using a 3-site forward sandwich monoclonal antibody based immunoradiometric assay (M-IRMA). Immunohistochemical studies demonstrated that brains with AD, AD + PD, and AD + DN contained significantly higher densities of NTP immunoreactive neurons and more frequent immunostaining of neuropil and white matter fibers compared with PDD and aged controls (both P < 0.001) which had few or no AD lesions. In addition, the overall mean concentrations of NTP in AD, AD + PD, and AD + DN were significantly higher than in PDD and aged controls (P < 0.005). Greater degrees of NTP immunoreactivity and higher concentrations of the protein in cerebral tissue were significantly correlated with AD diagnosis and abundant neurofibrillary tangles (P < 0.005). The findings suggest that NTP over-expression may serve as a marker for the type of neuronal degeneration that occurs in AD.

Aged↗
PubMed1992

Human non-hepatocytes support hepadnaviral replication and virion production.

The competence of non-hepatocytes to support hepatitis B virus (HBV) gene expression and replication was studied by transient transfection of various human cell lines with a head-to-tail dimer of HBV DNA. Independent of their neuroectodermal, mesenchymal or epithelial origin, all non-hepatocyte cell lines tested synthesized and secreted hepatitis B surface antigen (HBsAg) and hepatitis B core/e antigen (HBc/eAg). Further analyses of two of these cell lines (LS 180 and COLO 320) identified the two major HBV transcripts of 3.6 and 2.2/2.4 kb length, respectively. LS 180 cells were permissive for HBV and duck hepatitis B virus (DHBV) DNA replication and secretion of infectious virions. COLO 320 cells also supported HBV DNA replication, but did not appear to export complete viral particles. These findings provide direct evidence that both HBV and DHBV can replicate in non-hepatic tumour cell lines, one of which is shown also to produce infectious virions.

Blotting, Northern↗
PubMed1992

Hepatitis B virus X protein is not central to the viral life cycle in vitro.

The hepatitis B x (HBx) gene is the smallest open reading frame of the hepatitis B virus (HBV) genome. It is conserved among all mammalian hepadnaviruses and is expressed during viral infection. While the HBx protein (pX) has been shown to trans-activate the transcription of a wide range of viral and cellular genes and to induce liver cancer in transgenic mice, the significance of pX for the life cycle of HBV itself has not been elucidated. To assess the function of pX in viral replication and virion export, we designed an X-minus mutant by introduction of a stop codon at the beginning of the HBx gene without affecting the viral polymerase gene product. Transient transfection analyses using different cell lines revealed that this X-minus mutant directs the synthesis of wild-type levels of viral proteins, replicative intermediates, and virion export. These data suggest that the expression of the highly conserved HBx gene is not central for the life cycle of HBV in vitro but may be involved in the pathogenicity of hepadnavirus infection, including liver cancer development.

Base Sequence↗
PubMed1992

Immunohistochemical and histopathologic correlates of Alzheimer's disease-associated Alz-50 immunoreactivity quantified in homogenates of cerebral tissue.

Alz-50 is a monoclonal antibody that immunoreacts with neurofibrillary tangles and neurites in brains with Alzheimer's disease (AD). In addition, the levels of Alz-50 immunoreactivity in brain, measured by either enzyme-linked immunosorbent assay or ALZ-enzyme-linked immunosorbant assay (EIA), are increased in AD relative to age-matched controls. The current study compares the distribution and extent of Alz-50 immunostaining with quantified levels of Alz-50 immunoreactivity measured in adjacent frozen blocks of tissue by ALZ-EIA. The brain tissue studied was obtained from individuals with AD, AD + Down's syndrome (AD + DN), Parkinson's disease with dementia (PD), or AD + PD, and from nondemented aged controls. In AD, AD + DN, and AD + PD, there were significantly higher densities of Alz-50-immunoreactive (AFI) neurons, more abundant diffuse AFI neurites, and higher ALZ-EIA values than in aged controls. In PD, the overall mean density of AFI neurons was significantly lower than in AD and AD + DN, but AFI neurites were as abundant as they were in brains with an AD diagnosis. However, PD was readily distinguished from AD and AD + DN by significantly lower mean ALZ-EIA values, and significantly lower densities of neurofilament-immuno-reactive AD lesions. Multiple-regression analysis demonstrated significant correlations between ALZ-EIA levels and the severity of AD lesions, and the density of AFI neurites, but not with the density of AFI neurons. Therefore, ALZ-EIA levels may represent only a portion of the Alz-50 immunoreactivity detectable by immunohistochemical staining.

Alzheimer Disease↗
PubMed1991

A hepatitis B virus mutant associated with an epidemic of fulminant hepatitis.

BACKGROUND: A nosocomial outbreak of fulminant hepatitis B occurred in five patients in Haifa, Israel. Previous investigations identified the suspected source as a carrier of hepatitis B surface antigen who was positive for antibodies to hepatitis B e antigen and had chronic liver disease. We examined the strain of hepatitis B virus (HBV) that caused this epidemic, in order to identify specific mutations in the precore or core region. METHODS: The presence of HBV was identified by polymerase-chain-reaction amplification of viral DNA in serum from the source patient, the five patients with fulminant hepatitis B, and five controls with acute, self-limited hepatitis B. The amplified viral HBV DNA samples were then cloned and sequenced. RESULTS: Sequence analysis of viral DNA established that the same HBV mutant with two mutations in the precore region was present in the source patient and the five patients with fulminant hepatic failure. This HBV mutant had significant sequence divergence from other known HBV subtypes in the X, precore, and core regions. Cloned HBV DNA derived from a hospitalized patient who had subclinical hepatitis B at the same time as the outbreak and from four other control subjects with acute, self-limited hepatitis B all contained the wild-type sequence in the precore region. CONCLUSIONS: In the outbreak we studied, a mutant hepatitis B viral strain was transmitted from a common source to five patients who subsequently died of fulminant hepatitis B infection. Naturally occurring viral mutations hepatitis B infection. Naturally occurring viral mutations in the HBV genome may predispose the infected host to more severe liver injury.

Amino Acid Sequence↗
PubMed1991

Stability of monoclonal antibody-defined epitopes.

Epitope instability can limit the applications of monoclonal antibody (mAb) technology in laboratory and clinical research. We exposed a group of representative antigens on human hepatocellular carcinoma (HCC) cells to physiochemical insults to study epitope stability as measured by mAb immunoreactivity. Each epitope was found to have a unique pattern of instability which serves to biophysically characterize the antigen and defines the conditions to which the antigen can be exposed during laboratory and clinical investigations. Individual antigens were found to be unstable within a surprisingly well defined window of solvent polarities while being stable on either side of that window. Several antigens were observed to be unstable when exposed to transient changes in pH. When a critical temperature between 42 degrees C and 65 degrees C was achieved, epitopes which were thermosensitive underwent a sudden loss in immunoreactivity. This critical temperature was found to be pH dependent. The effects of polarity, pH, and temperature on epitope stability are consistent with changes in protein structural conformation. In addition, we found that certain fixatives cause a time and concentration dependent loss of epitope immunoreactivity. This study provides a rapid and easy determination of monoclonal antibody-defined epitope stability; the results of which serve to guide further studies on the antigen and to characterize the antigen on the basis of its unique physiochemical stability.

Animals↗
PubMed1991

Persistence of hepatitis B viral DNA after serological recovery from hepatitis B virus infection.

Chronic hepatitis B virus infection is a major medical problem worldwide. Apart from HBsAg carriers, hepatitis B virus has also been identified in some HBsAg-individuals with or without antibodies to viral antigens. The molecular mechanisms underlying hepatitis B virus persistence in HBsAg-individuals are unresolved, however. To identify a possible genetic basis for viral persistence, we cloned the viral genome from the liver of a patient serologically immune to hepatitis B virus infection. DNA sequence analysis of the complete viral genome identified numerous mutations in all viral genes. Analysis of the biological effects of these mutations revealed three major findings: a low level of HBsAg synthesis, absence of HBeAg production and a defect terminating viral replication. These data suggest that mutations accumulating during the natural course of hepatitis B virus infection may be a mechanism underlying viral persistence in HBsAg-individuals, presumably through escape from immune surveillance.

Aged↗
PubMed1991

Association of hepatitis B viral precore mutations with fulminant hepatitis B in Japan.

We studied the precore DNA sequences of hepatitis B viral genomes in five patients with fulminant hepatitis B and in five with acute self-limited hepatitis B from Japan. Using the polymerase chain reaction, three to four independent HBV DNA clones from each patient were obtained and analyzed. We demonstrated that patients with fulminant hepatitis B carried HBV genomes with a G to A mutation at nucleotide positions 1898 (five of five patients; 18 of 18 clones, 100%) and 1901 (five of five patients; 12 of 18 clones, 66%) in the precore region. The first mutation results in an in-phase stop codon (TAG) in the precore open reading frame and the absence of HBeAg production. In contrast, a G to A mutation was found in 6 of 16 clones (37%) in position 1898 and in 0 of 16 clones (0%) in position 1901 from patients with acute self-limited hepatitis. We concluded that both of the precore mutations are commonly associated with fulminant hepatitis B and may contribute to the pathogenesis of fulminant hepatitis. A hypothetical model for the biological significance of these two mutations is proposed.

Adult↗
PubMed1991

Naturally occurring missense mutation in the polymerase gene terminating hepatitis B virus replication.

A hepatitis B virus (HBV) genome was cloned from human liver. Numerous mutations in all viral genes define this HBV DNA as a mutant, divergent from all known HBV DNA sequences. Functional analyses of this mutant demonstrated a defect blocking viral DNA synthesis. The genetic basis of this defect was identified as a single missense mutation in the 5' region of the viral polymerase gene, resulting in the inability to package pregenomic RNA into core particles. The replication defect could be trans-complemented by a full-length wild-type, but not by a full-length mutant or 3'-truncated wild-type, polymerase gene construct. Our findings indicate a critical role of the 5' polymerase gene region in the life cycle of the virus and suggest that introducing missense mutations in this region can be a strategy to terminate viral replication in vivo.

Base Sequence↗
PubMed1991

Hepatitis B virus infection in patients with idiopathic liver disease.

We studied 67 HBsAg-negative Israeli patients (36 negative for all HBV serological markers as group 1 and 31 positive for antibodies to HBs and HBc as group 2) with chronic liver disease and cirrhosis of unknown origin using a rapid, sensitive and specific assay for the detection of low levels of hepatitis B virus in serum. This technique uses a high-affinity monoclonal antibody to HBs against an a domain epitope of HBsAg to capture the virion, followed by hepatitis B virus DNA amplification with the polymerase chain reaction. In addition, 55 subjects without liver disease served as controls: Group 3 (n = 32) was negative for all hepatitis B virus markers; group 4 (n = 23) was positive for antibodies to HBs and HBc. We found 11 individuals in group 1 (31%) and 10 in group 2 (29%) harboring low levels of hepatitis B virus DNA in serum. In contrast, no one in group 3 or group 4 was positive by this technique (p less than 0.0001). Using polymerase chain reaction primers spanning other regions of the hepatitis B virus genome and a method of restriction-fragment analysis of polymerase chain reaction-amplified sequences, we detected significant DNA sequence heterogeneity, suggesting infection with distinct hepatitis B virus strains. DNA extracted from paraffin-embedded liver biopsy specimens of 42 patients from groups 1 and 2 was shown to contain hepatitis B virus DNA by polymerase chain reaction in 11 of 12 patients with circulating virion DNA. More important, 18 additional patients whose sera were negative by HBs-antibody capture/polymerase chain reaction amplification had hepatitis B virus DNA sequences in their livers.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Disease↗
PubMed1990

Expression of human alpha-actinin in human hepatocellular carcinoma.

Little is known regarding gene expression during hepatocyte transformation. We have isolated an alpha-actinin complementary DNA from a human hepatocellular carcinoma library. This partial 2.4-kilobase complementary DNA has high homology with human placental and chicken nonmuscle alpha-actinins; our isolate contains the entire 3' noncoding region and it is within these sequences where the major differences between the vertebrate alpha-actinin complementary DNAs arise. Northern analysis revealed a 3.5-kilobase transcript in nonmuscle and a smaller 3.0-kilobase species in muscle tissue. Levels of alpha-actinin expression were low in normal liver and we investigated its expression during both hepatocyte proliferation and transformation. We found no increase during rat hepatocyte regeneration up to 24 h following two-thirds hepatectomy. However, high levels of alpha-actinin transcripts were observed in human hepatocellular carcinoma compared to noninvolved adjacent liver. We conclude that the alpha-actinin gene is highly expressed when hepatocytes have assumed the malignant phenotype.

Actinin↗
PubMed1990

Abnormal maternal serum levels of human chorionic gonadotropin free subunits in trisomy 18.

We have measured maternal serum levels of free alpha and beta subunits of human chorionic gonadotropin between 8 and 12 weeks of gestation in 704 women at increased risk for trisomy. This group was studied because of advanced maternal age or a previous birth with chromosomal abnormality. All sera had been collected prior to chorion villus biopsy for prenatal diagnosis. Serum levels of free alpha and beta hCG were determined by specific monoclonal antibody-based immunoradiometric assays. Analysis of chorionic tissue showed that in 38 of 704 (5.4%) pregnancies the fetus had a chromosome abnormality. There were 8 fetuses with trisomy 18 (1.1%) and 9 (1.3%) with trisomy 21. In all pregnancies carrying a trisomy 18 fetus, we observed either high levels of free alpha hCG or low levels of free beta hCG or both. More importantly, the calculated ratio of free beta hCG/alpha hCG was less than 0.25 multiples of the median (MoM) in 6 of 8 (75%) trisomy 18 cases. Only 21 of 666 mothers (3.2%) carrying a normal fetus had a ratio less than 0.25 MoM (P less than 0.0001). There was no difference between this ratio in trisomy 21 and normal pregnancy. Thus, when adjusted for gestational age, a low free beta hCG/alpha hCG ratio in maternal serum indicates a pregnancy at high risk [RR = 72 (95% CI 32, 162)] for trisomy 18.

Chorionic Gonadotropin↗
PubMed1990

Characterization and biological properties of a hepatitis B virus isolated from a patient without hepatitis B virus serologic markers.

We have developed a rapid method to characterize genomic diversity of low-level hepatitis B and related viral agents after their identification in serum by high-affinity HBsAg-antibody monoclonal antibody capture and subsequent polymerase chain reaction amplification. Serum from an individual with chronic liver disease and without hepatitis B virus serological markers but reactive by monoclonal antibody capture/polymerase chain reaction amplification was inoculated into a chimpanzee. After inoculation, an acute hepatitis B virus-like hepatitis developed in the chimpanzee. Analysis of serial liver biopsy samples showed the persistence of hepatitis B virus DNA for more than 17 mo after resolution of acute hepatitis and seroconversion. Applying the technique of restriction enzyme fragment analysis to serial chimpanzee liver biopsy samples and acute-phase sera, along with the serum inoculum, we established that all hepatitis B virus DNA sequences are derived from the same viral agent. We present evidence that the viral DNA persisted as a nonreplicating episomal form in the nucleus of hepatocytes. This study demonstrates that after clinical and serological recovery from an acute hepatitis, there may be persistence of low-level hepatitis B virus-related genome in the liver despite the presence of antibodies to HBsAg. Such persistence of viral genome may be a natural sequela of infection and may serve as a source of viral latency and possible reactivation. Finally, cloning and complete nucleic-acid sequencing of this virus have demonstrated multiple nucleotide and amino acid changes compared with all known hepatitis B virus subtypes. These changes may have contributed in part to a different antigenic composition or immunological reactivity of the host to this hepatitis B virus isolate.

Animals↗