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Biomedical subjects

S J Robbins

Publications and source records attributed to S J Robbins.

35 records · Page 2Linked to original sources
PubMed1988

Variation in dengue type 2 viruses isolated in Bangkok during 1980.

Dengue type-2 viruses isolated in metropolitan Bangkok during 1980 (Bangkok/80) were characterized by oligonucleotide fingerprinting, restriction enzyme (RE) mapping and antigenic analysis using monoclonal antibody probes. Of 10 isolates analysed by oligonucleotide fingerprinting, nine were very closely related, showing 72.5% to 91.4% oligonucleotide homology. One isolate (D80-141) produced a distinctly different fingerprint (55.7% to 58.0% homology) and was less related to other Bangkok/80 dengue-2 virus isolates than to a 1964 Bangkok isolate (16681). RE mapping conducted on complementary dsDNA prepared from three Bangkok/80 isolates, strain 16681 and the prototype New Guinea C strain confirmed that D80-141 was genetically distinct. On antigenic analysis, only one of 22 monoclonal antibody probes produced against representative 1980 Bangkok dengue-2 isolates, D80-100 and D80-141, was able to distinguish between these virus strains. Monoclonal antibody 47-10/10, prepared using D80-100 virus and directed at the NS1 non-structural glycoprotein, had a significantly lower (100-fold) solid phase radioimmune assay endpoint titre for D80-141 antigen than for D80-100 antigen. By the indirect immunofluorescence assay, 47-10/10 had lower antibody endpoint titres against D80-141, the NGC strain and 13 (12%) of 110 Bangkok/80 isolates than to a control antibody preparation. These results suggest that strain D80-141 represents a second minor topotype of dengue-2 which was circulating concurrently with the major endemic topotype in Bangkok in early 1980.

Antibodies, Monoclonal↗
PubMed1985

A rapid method for the purification of cytoplasmic paramyxoviral nucleocapsids.

A rapid method for the purification of cytoplasmic paramyxoviral nucleocapsids using a tabletop ultracentrifuge is described. The method yields materials equivalent in purity to materials purified by previously published procedures but requires only a fraction of the time (65 min vs 7-41.5 h). When used in conjunction with modern hypersensitive analytical techniques, the procedure provides equivalent or greater amounts of nucleocapsid for subsequent analysis or study.

Amnion↗
PubMed1985

Enhanced intranuclear expression of measles virus following exposure of persistently infected cells to cyclic AMP.

The intracellular distribution of measles virus inclusion bodies in persistently infected human cells (AV3A1/MV) changed markedly following continuous exposure to 3', 5' cyclic adenosine monophosphate (cAMP). When assayed by immunofluorescence, the number of cells with intranuclear virus inclusions increased from 5 to 10% to 80 to 90% after exposure to 1 mM-cAMP for 4 days. Exposure of cells to cAMP also resulted in a twofold increase in the average number of inclusions in invaded nuclei. Similar but less pronounced changes occurred in cells treated with inducers of adenylate cyclase and an inhibitor of phosphodiesterase. Examination of cAMP-treated cells by electron microscopy indicated that viral inclusion bodies consisted of typical helical nucleocapsids. No evidence of nucleocapsids crossing the nuclear membrane (through nuclear pores) was found.

Adenylyl Cyclases↗
PubMed1984

Subacute sclerosing panencephalitis (SSPE): a report of 16 cases.

Sixteen cases of subacute sclerosing panencephalitis (SSPE) were diagnosed at the Royal Children's and Mater Misericordiae Children's Hospitals in Brisbane from September 1974 to June 1983. Although the incidence of the disease with regard to age at onset, previous exposure to measles virus, and longevity was similar to that reported in the United States and Europe, the frequency of the illness was substantially higher in the present study. The high frequency of the disease in Queensland appears to reflect a relatively low level of immunity to measles virus in the population at risk.

Antibodies, Viral↗
PubMed1983

Progressive invasion of cell nuclei by measles virus in persistently infected human cells.

The distribution of measles virus antigens in an auto-degenerating persistently infected human cell line (AV3A1/MV) was examined by a direct fluorescent antibody technique. The appearance of virus antigens in cell nuclei increased with time and passage number, and correlated to a decrease in cell replication rates and increases in cellular pathology and mortality. Nuclei which had been invaded by virus antigens were frequently swollen and the cells tended to have round rather than cuboidal morphologies. The correlation between cell degeneration and viral nuclear invasion in this system suggests that quantification of viral nuclear invasion may be useful as a pathological marker of relative cell morbidity in persistent measles virus infections.

Amnion↗
PubMed1982

Restriction of virus-specific protein synthesis in a persistent paramyxovirus infection.

Synthesis of virus-specific proteins in a persistent, nonproductive paramyxovirus infection derived from the peripheral blood leukocytes of a patient with subacute sclerosing panencephalitis (SSPE) was investigated. The persistently infected cells expressed cytoplasmic virus-specific antigens and generated paramyxovirus nucleocapsids throughout long-term passage. When analyzed by specific immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, most of the virus structural proteins were synthesized in acutely infected cells, but only three of the proteins could be readily detected in persistently infected cells. The two structural proteins whose synthesis was most clearly restricted had molecular weights of 69,000 and 41,000 daltons and represented the putative HN and M virus proteins. The similarities between the restriction of virus protein synthesis in this system and that reported previously for other persistent paramyxovirus infections derived from SSPE suggest that a common mechanism may be involved in the maintenance of such infections.

Amnion↗
PubMed1981

Rescue of a cytopathic paramyxovirus from peripheral blood leukocytes in subacute sclerosing panencephalitis.

An infectious, cytopathic paramyxovirus was rescued from the peripheral blood leukocytes of a patient with subacute sclerosing panencephalitis (SSPE) by cocultivation procedures. Cells infected with the virus (1) demonstrated polykaryocytosis, (2) contained cytoplasmic inclusion bodies of paramyxoviral nucleocapsids, (3) hemadsorbed monkey erythrocytes, and (4) reacted with fluorescein-conjugated antisera to measles virus. On the basis of these observations, the virus was initially believed to be measles-like virus similar to those that have been rescued from other patients with SSPE. However, subsequent immunologic and molecular studies showed that the virus was distinct from measles virus and was more closely related to simian virus 5. These findings suggest that paramyxoviruses other than measles virus can be nonproductively carried by patients with SSPE and should not be designated as "measles like" or "measles related" solely on the basis of their biologic characteristics.

Adolescent↗
PubMed1981

Evolution of a human cell line persistently infected with measles virus.

A measles-virus-carrier cell line, designated AV3/MV, was derived from established human amnion (AV3) cells surviving primary infection with the Edmonston strain of measles virus. During maintenance of infected cultures in the laboratory, the cells passed from a highly productive chronic phase (where infectious virus was continuously shed) to a less productive degenerative phase (where fewer infectious particles were produced). Carrier cultures in the less-productive phase gradually deteriorated and failed to survive at 37 degrees. However, when temporarily maintained and passaged at 39.5 degrees, the cultures stabilized and carried the virus in a latent or nonproductive state. Carrier cultures in the chronic phase of infection expressed variable degrees of virus-specific CPE, replicated erratically, and generated large amounts of virus-specific antigens. In the stabilized latent phase, the cultures demonstrated no virus-specific CPE, replicated steadily, and generated reduced amounts of virus-specific antigens. The results of our studies indicate that the establishment and maintenance of persistent measles virus infections in AV3 cells are dynamic processes involving numerous variables, and that there are similarities between these latent-carrier cell lines and certain virus-carrier cell lines derived from subacute sclerosing panencephalitis brain tissues.

Amnion↗
PubMed1981

Characterization of nonmeasles paramyxovirus isolates from a patient with subacute sclerosing panencephalitis.

Two paramyxovirus isolates recovered from the peripheral blood leukocytes of a patient with subacute sclerosing panencephalitis were characterized by biological, immunological, and molecular techniques. Both virus isolates possessed neuraminidase activity but demonstrated reduced hemagglutination potential. Neutralization titrations showed that the viruses were clearly related to, but were distinct from, simian virus 5. Characterization of purified virus preparations by SDS-PAGE showed that the structural polypeptides of the viruses were similar to those of simian virus 5, but distinct differences were noted as well. In addition, the virus isolates were found to differ from one another, particularly with regard to the major putative transcriptase protein (L).

Adolescent↗
PubMed1980

Isolation and partial characterization of two forms of cytoplasmic nucleocapsids from measles virus-infected cells.

Two species of measles virus nucleocapsids with distinct buoyant densities were isolated from infected AV3 cell homogenates by isopycnic CsCl gradient centrifugation. The more buoyant or 'light' form of the nucleocapsid had a density of 1.26 to 1.28 g/ml, whereas the less buoyant or 'heavy' nucleocapsid species had a density of 1.30 g/ml. Analysis of the two nucleocapsid species by SDS--polyacrylamide gel electrophoresis showed that both forms possessed two phosphorylated polypeptides with mol. wt. of 69000 and 60000. The heavy form of nucleocapsid consisted solely of these two polypeptide species, while the light form of nucleocapsid had two additional associated polypeptides (VP4, mol.wt. 52000, and 45K, mol. wt. 45000). Ultrastructural and immunofluorescent studies suggest that the two isolated capsid forms represent the two morphologically distinct capsid species observed in vivo. This paper discusses the possible relationship between the two capsid forms and assembly of the virus.

Amnion↗
PubMed1980

Structural phosphoproteins associated with measles virus nucleocapsids from persistently infected cells.

Measles virus nucleocapsids were labelled with 3H-amino acids and 32P-orthlls (AV+). When analysed by SDS-PAGE, the two major capsid-associated polypeptides (P, mol. wt. 69,000, and NP, mol. wt. 60,000) were shown to be phosphorylated. Subsequent characterization of the phosphorylated polypeptides by acid hydrolysis and high voltage paper electrophoresis showed that serine and threonine were the major phosphorylated amino acid species. The similarities between the peptide phosphorylation patterns obtained in these studies and those reported earlier for the virus phosphoproteins produced in acute infections (Robbins & Bussell, 1979) indicate that major phosphorylative modifications of the capsid proteins are not involvedin measles virus persistence in AV3 cells.

Amnion↗
PubMed1979

Structural phosphoproteins associated with purified measles virions and cytoplasmic nucleocapsids.

Measles virions and cytoplasmic nucleocapsids were labeled with [3H]-amino acids and [32P]-orthophosphate and were purified from infected Vero cells. When analyzed by PAGE, the two capsid-associated polypeptides (VP2 -- 69,000 daltons, VP3 -- 60,000 daltons) were shown to be phosphorylated. Characterization of the phosphorylated polypeptides by acid hydrolysis and high-voltage paper electrophoresis showed that serine was the major phosphorylated amino acid, although lesser amounts of phosphothreonine were also present. The possible role of phosphorylation in the replication cycle of the virus is discussed.

Amino Acids↗
PubMedDate not supplied

Using cue reactivity to screen medications for cocaine abuse: a test of amantadine hydrochloride.

The use of responding to drug-related stimuli as a dependent measure for studies of anticraving medications was assessed. Cocaine-dependent subjects receiving either amantadine hydrochloride, a putative anticraving agent, or placebo were exposed to drug-related cues prior to and 7 days after the initiation of the medication. Measurements of heart rate, skin resistance, skin temperature, and self-reported craving were taken during each stimulus session. Amantadine increased physiological reactivity to the drug-related cues compared to the placebo while having no effect on craving. Although the results discourage the use of amantadine as an anticraving medication, they do suggest that responses elicited by drug-related stimuli provide a valuable set of dependent measures for use in future medication trials of anticraving agents.

Adult↗
PubMedDate not supplied

Relationships among physiological and self-report responses produced by cocaine-related cues.

In response to cocaine cues, 150 subjects with a history of cocaine abuse showed decreases in skin temperature and skin resistance and increases in heart rate and reported craving, high, and withdrawal responses. These responses were consistent across four years of data collection. Craving reports were not consistently associated with either high or withdrawal responses, and many subjects endorsed increases in both high and withdrawal states. Correlations revealed no pattern of association among physiological variables and responding did not differ between subjects who did and those who did not report increases in each of the drug states. Finally, physiological variables did not predict reported drug states in discriminant analyses. Cocaine cue reactivity cannot be easily related to a unitary state of high, withdrawal, or craving. It is suggested that future studies focus more on the prediction and measurement of treatment outcome than on the form of cue responses.

Adult↗
PubMedDate not supplied

Laboratory exposure to cocaine cues does not increase cocaine use by outpatient subjects.

Sixty-nine cocaine-dependent outpatients were exposed to cocaine-related stimuli and to non-drug events on separate days. Cocaine cue sessions were always followed by a meeting with a trained clinician designed to eliminate any craving that remained following cue presentations. Urine samples were collected before each laboratory session and 1 to 3 days later. Neither rates of cocaine use nor average urine metabolite values differed following the two sessions. Nearly 90% of subjects had the same urine test result both before and after the cocaine cue session. Thus, laboratory presentation of cocaine cues to outpatient subjects did not increase their risk of subsequent drug-taking. These results suggest that with proper clinical protections, cue exposure can be used as a treatment outcome measure and a behavioral intervention in outpatient settings without increasing the risk of drug use.

Adult↗