Serotonin 5-HT1 receptors potentiate histamine and thrombin stimulated prostaglandin synthesis in endothelial cells.

The ability of serotonin 5-HT1 receptors to increase vascular tone was previously found to be activated by vasoconstrictiors such as histamine. In this study, treatment of cultured human aortic endothelial cells (HAEC) with the 5-HT1-selective agonist 5-carboxamidotryptamine (5-CT) alone had no effect on the levels of prostaglandin F2alpha (PGF2alpha) or 6-keto-prostaglandin F1alpha (6-keto PGF1alpha). However, 5-CT potentiated the histamine and thrombin stimulated increases in prostaglandins released by HAEC. In the presence of histamine, increasing doses of 5-CT caused a steep rise in PGF2alpha levels resulting in an increase in the ratio of PGF2alpha over 6-keto PGF1alpha. The ability of 5-CT to potentiate prostaglandin production was correlated with its ability to potentiate the histamine and thrombin mediated mobilization of arachidonic acid. These results demonstrate that the ability of 5-HT1 receptors to stimulate prostaglandin production in endothelial cells is activated by histamine and thrombin.

Public health informatics: improving and transforming public health in the information age.

Development of effective public health information systems requires understanding public health informatics (PHI), the systematic application of information and computer science and technology to public health practice, research, and learning. PHI is distinguished from other informatics specialties by its focus on prevention in populations, use of a wide range of interventions to achieve its goals, and the constraints of operating in a governmental context. The current need for PHI arises from dramatic improvements in information technology, new pressures on the public health system, and changes in medical care delivery. Application of PHI principles provides unprecedented opportunities to build healthier communities.

The activation of plasminogen activator inhibitor-1 expression by IL-1beta is attenuated by estrogen in hepatoblastoma HepG2 cells expressing estrogen receptor alpha.

A low estrogen status in postmenopausal women is associated with elevated plasma levels of plasminogen activator inhibitor-1 (PAI-1). In this study, the ability of estrogen compounds to regulate PAI-1 expression was determined in a hepatocyte HepG2 cell line made to stably express estrogen receptor alpha (ERalpha). In both the wild type and ER expressing HepG2 cells, estrogen had no effect on basal PAI-1 expression. However, in the ER expressing cells the ability of IL-1beta to increase PAI-1 mRNA and protein levels was attenuated by 17beta-estradiol, tamoxifen and twelve estrogen components of Premarin. In contrast, the mixed agonist/antagonist raloxifene had weak agonist activity and like the pure antagonist ICI 182780, it dose dependently blocked the effect of 17beta-estradiol on IL-1beta stimulated PAI-1 levels. These results suggest that estrogen agonists may lower PAI-1 levels in vivo by inhibiting cytokine activated PAI-1 expression by an ER dependent mechanism.

Epidemiologic evidence for a new class of compounds associated with toxic oil syndrome.

Toxic oil syndrome appeared in epidemic form in Spain in 1981. Epidemiologic studies have demonstrated that illness was caused by consumption of rapeseed oil that had been denatured with aniline. Chemical analyses of oil specimens conducted in conjunction with epidemiologic studies have established that consumption of specific oils containing fatty acid anilide contaminants was associated with increased risk for disease. New chemical analytic methods identified a family of compounds, the di-fatty acid esters of phenylamino propane-diol, and one of these compounds, the 1,2-di-oleyl ester of 3-(N-phenylamino)-1,2-propanediol (DPAP), has been found to be more strongly associated with disease status than the fatty acid anilides. We found the odds ratio for exposure to DPAP (OR = 26.4, 95% CI = 6.4-76.3) is much higher than the odds ratio for exposure to oleyl anilide (OR = 4.1, 95% CI = 2.2-7.8), implying that exposure to DPAP was a more relevant risk factor for development of toxic oil syndrome than exposure to oleyl anilide. In this paper, we review and present analyses of data from multiple studies of the possible etiologic role of DPAP in toxic oil syndrome. The presence of DPAP in oil collected from affected and unaffected households was a more specific correlate of case relatedness than was the presence of fatty acid anilides, and it was equally sensitive. Moreover, DPAP was found in oil from the only refinery whose oil was clearly associated with illness.

Differences in the biological phenotype of low-yielding (L) and high-yielding (H) variants of swine influenza virus A/NJ/11/76 are associated with their different receptor-binding activity.

Low- (L) and high-yielding (H) variants of A/sw/NJ/11/76 influenza virus were compared for their growth properties in embryonated chicken eggs and MDCK cells and for their binding affinity for the membrane fractions prepared from cells of the chicken embryo allantoic membrane. MDCK, and swine tracheal cells, as well as for soluble sialic acid containing macromolecules and monovalent sialosides. We have shown, that during infection in MDCK cells and in eggs, the progeny of the L variant remain predominantly cell associated, in contrast to those of H. As a result, accumulation of the L mutant in allantoic or culture fluid is significantly slowed in comparison with the H variant. Visualization of the infectious foci formed by the viruses in MDCK cell monolayers and on the allantoic membrane revealed that L spreads predominantly from cell to cell, while the spread of H involves release of the virus progeny into solution and its rapid distribution over the cell monolayer via convectional flow of the liquid. In the binding assays, L displayed significantly higher binding affinity than H for cellular membranes, gangliosides, and sialylglycoproteins, however, the affinity of the variants for the monovalent sialic acid compounds was comparable. Unlike H. L bound strongly to dextran sulfate. The data obtained suggest that all distinctions of the L and H biological phenotypes reported previously [Kilbourne, E.D., Taylor, A. H. Whitaker, C.W., Sahai, R., and Caton, A (1988) Hemagglutinin polymorphism as the basis for low-and high-yield phenotypes of swine influenza virus. Proc. Natl. Acad. Sci. USA 85, 7782-7785] could be rationally explained by a more avid binding of the L variant to the surface of target cells, and that this effect is mainly due to enhanced electrostatic interactions.

Supplementation of conventional influenza A vaccine with purified viral neuraminidase results in a balanced and broadened immune response.

Influenza virus neuraminidase was chromatographically extracted from A/Johannesburg/33/94 (H3N2) and used to supplement conventional monovalent H3JHN2JH inactivated influenza vaccine. Immunization of mice with this preparation resulted in high titers of antibodies to both hemagglutinin (HA) and neuraminidase (NA) equivalent for each antigen to titers in animals immunized with either antigen alone. Homotypic infection was suppressed and greater reduction in viral replication was observed following heterotypic infectious challenge than was observed following the non-supplemented vaccine. There was no evidence of suppression of the immune response to the HA despite the presence of high amounts of NA in the vaccine. Supplementation of conventional inactivated influenza vaccine with NA takes advantage of the equivalent immunogenicity of dissociated HA and NA, to produce a more balanced immune response to both surface antigens, without the antigenic competition tht occurs after immunization with conventional vaccine or infection. These studies in a mouse model system suggest that supplementation of current inactivated influenza vaccines offers the prospect of improved immunization of humans against influenza.

E1A represses apolipoprotein AI enhancer activity in liver cells through a pRb- and CBP-independent pathway.

The apolipoprotein AI (apoAI) promoter/enhancer contains multiple cis -acting elements on which a variety of hepatocyte-enriched and ubiquitous transcription factors function synergistically to regulate liver-specific transcription. Adenovirus E1A proteins repress tissue-specific gene expression and disrupt the differentiated state in a variety of cell types. In this study expression of E1A 12Sor 13S in hepatoblastoma HepG2 cells repressed apoAI enhancer activity 8-fold. Deletion mapping analysis showed that inhibition by E1A was mediated by the apoAI promoter site B. E1A selectively inhibited the ability of HNF3beta and HNF3alpha to transactivate reporter genes controlled by the apoAI site B and the HNF3 binding site from the transthyretin promoter. The E1A-mediated repression of HNF3 activity was not reversed by overexpression of HNF3beta nor did E1A alter nuclear HNF3beta protein levels or inhibit HNF3 binding to DNA in mobility shift assays. Overexpression of two cofactors known to interact with E1A, pRb and CBP failed to overcome inhibition of HNF3 activity. Similarly, mutations in E1A that disrupt its interaction with pRb or CBP did not compromise its ability to repress HNF3beta transcriptional activity. These data suggest that E1A inhibits HNF3 activity by inactivating a limiting cofactor(s) distinct from pRb or CBP.

Toxic oil syndrome mortality: the first 13 years.

BACKGROUND: The toxic oil syndrome (TOS) epidemic that occurred in Spain in the spring of 1981 caused approximately 20000 cases of a new illness. Overall mortality and mortality by cause in this cohort through 1994 are described for the first time in this report. METHODS: We contacted, via mail or telephone, almost every living member of the cohort and family members of those who were known to have died in order to identify all deaths from 1 May 1981 through 31 December 1994. Cause of death data were collected from death certificates and underlying causes of death were coded using the International Classification of Diseases, 9th Revision. RESULTS: We identified 1663 deaths between 1 May 1981 and 31 December 1994 among 19 754 TOS cohort members, for a crude mortality rate of 8.4%. Mortality was highest during 1981, with a standardized mortality ratio (SMR) of 4.92 (95% confidence interval [CI]: 4.39-5.50) compared with the Spanish population as a whole. The highest SMR, (20.41, 95% CI: 15.97-25.71) was seen among women aged 20-39 years during the period from 1 May 1981 through 31 December 1982. Women <40 years old, who were affected by TOS , were at greater risk for death in most time periods than their unaffected peers, while older women and men were not. Over the follow-up period, mortality of the cohort was less than expected when compared with mortality of the general Spanish population, or with mortality of the population of the 14 provinces where the epidemic occurred. We also found that, except for deaths attributed to external causes including TOS and deaths due to pulmonary hypertension, all causes of death were decreased in TOS patients compared to the Spanish population. The most frequent underlying causes of death were TOS, 350 (21.1%); circulatory disorders, 536 (32.3%); and malignancies, 310 (18.7%). CONCLUSIONS: We conclude that while on average people affected by toxic oil syndrome are not at greater risk for death over the 13-year study period than any of the comparison groups, women <40 years old were at greater risk of death.

Perspectives on pandemics: a research agenda.

During the 20th century, indisputable pandemics of influenza occurred in 1918, 1957, and 1968. The pandemics of 1957 (A/H2N2) and 1968 (A/H3N2) were associated with major antigenic changes in the virus, probably reflecting introduction by recombination of animal virus genes. The 1918 epidemic is beyond the reach of modern virology but, based on seroarcheology, appears to have been caused by a virus very similar to present swine (A/H1N1) influenza viruses. Changes in both principal antigens of the A/H1N1 subtype in 1947 resulted in total vaccine failure and pandemic spread of virus. On the basis of three periods of prevalence in the 20th century, A/H1N1 may be the "default" human virus, although the 39-year persistence of A/H3N2 to the present challenges this view. Only H1, H2, and H3 and N1 and N2 antigens have been found in human influenza viruses, but virologic history is too brief to preclude the contribution of other antigens to future pandemics.

In pursuit of influenza: Fort Monmouth to Valhalla (and back).

In reviewing 50 years of personal research on influenza, I have journeyed, literally and figuratively, from an army camp epidemic in Fort Monmouth NJ in 1947 to a (literal and figurative) Valhalla, where I now conduct my research. Having entered the field as a physician, I have always sought practical applications of my work, yet in every instance, such applications have led me to seek further answers in basic research as new questions arose. I entered the area of influenza virus genetics by the back door through an interest in the effects of corticosteroid hormones on viral replication, used the genetic approach in analyzing the morphological variation of the virus and, in so doing, exploited the finding of a linkage of high-yield growth to spherical morphology. Today, all influenza vaccine viruses are high-yield genetic reassortants. Subsequent study of reassortant viruses facilitated the identification and isolation of the two major antigens of the virus in antigenic hybrids and showed their differing functions in the induction of immunity. In turn, a new approach to influenza vaccination has been discovered and is presently under clinical investigation.

Immunization with dissociated neuraminidase, matrix, and nucleoproteins from influenza A virus eliminates cognate help and antigenic competition.

When hemagglutinin (HA) and neuraminidase (NA) are presented together on an intact influenza virus particle, the antigens are competitive, with HA dominant over NA in T- and B-cell priming. Immunization with mixtures of purified HA and NA eliminates antigenic competition between HA and NA, as well as between N1-N2 NA mixtures. Evidence that vaccine preparations contain influenza virus matrix (M1) and nucleoprotein (NP) prompted the investigation of possible competing effects of these proteins on the anti-HA and anti-NA immune response. However, in BALB/c mice immunized with mixtures of purified NA, M1, and NP no antigenic competition was demonstrated in either the primary or the secondary response. When mice were immunized with intact virus or by infection, a lesser antibody response to M1 and NP was observed. Furthermore, as measured by mean pulmonary virus titers after infection, no additional protective effects were conferred on mice immunized with M1 and NP either alone or in conjunction with other antigens. These studies of influenza virus antigen mixtures have implications for vaccination against influenza and other vaccines consisting of combinations of antigens.

Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome.

Evidence from an array of scientific studies strongly supports the conclusion that ingestion of products containing L-tryptophan (LT) produced by Showa Denko KK caused the 1989 epidemic of eosinophilia-myalgia syndrome (EMS) in the United State. In case-control studies of EMS, LT exposure was essentially universal among cases but rare among controls. Of 6 manufacturers of LT, only LT manufactured by Showa Denko KK was clearly associated with illness. The data meet other Hill criteria for inferring a causal relationship. Consistent findings were found in multiple independently conducted studies. There was a dose-response effect, with risk of illness increasing as a function of the amount of tryptophan consumed. The extremely small p values observed in the multiple independently conducted studies effectively rule out the possibility that the tryptophan-EMS association was the result of chance. Moreover, no potential confounding factor or bias explains the association. The incidence of EMS in the United States diminished abruptly once LT containing products were recalled.

Neuraminidase-specific antibody responses to inactivated influenza virus vaccine in young and elderly adults.

Little information is available on the potential role of antibody to influenza virus neuraminidase (NA) in vaccine-induced immunity. In the present study, serologic responses to the N1Texas/91 and N2Beijing/92 NA components of trivalent inactivated influenza virus vaccine were measured by NA inhibition (NI) and enzyme-linked immunosorbent assay (ELISA), and the results for adults aged 18 to 45 (young) or > or = 65 (elderly) years were compared. The two age groups had comparable rates (32 to 50%) of NI response. In contrast, ELISA immunoglobulin G (IgG) antibody responses to N1 and N2 NAs occurred in 70 to 71 and 67 to 83%, respectively, of young subjects but in only 3 to 18 and 18 to 35%, respectively, of elderly subjects. prevaccination mean ELISA IgG and IgA NA antibody titers were generally lower for the young adults than they were for the elderly, whereas the corresponding NI titers were comparable. In young adults, plaque size-reducing NA antibody increases were positively associated with ELISA but not with NI antibody increases. There were no apparent age-related differences in the immunoglobulin isotype distribution of the anti-NA response, with IgG being the dominant class and IgG1 the dominant subclass of serum antibody. Anti-hemagglutinin antibody responses to H1Texas/91 and H3Beijing/92 were greater in magnitude and frequency than the corresponding NA-specific responses to N1Texas/91 and N2Beijing/92 when measured by hemagglutination inhibition and NI, respectively, but not when measured by ELISA. The discordance between NI and ELISA for measurement of NA-specific vaccine responses may reflect the relative insensitivity of NI in discriminating differences when initial antibody titers are low.

Control of apolipoprotein AI gene expression through synergistic interactions between hepatocyte nuclear factors 3 and 4.

Apolipoprotein AI (apoAI) gene expression in liver depends on synergistic interactions between transcription factors bound to three distinct sites (A, B, and C) within a hepatocyte-specific enhancer in the 5'-flanking region of the gene. In this study, we showed that a segment spanning sites A and B retains substantial levels of enhancer activity in hepatoblastoma HepG2 cells and that sites A and B are occupied by the liver-enriched hepatocyte nuclear factors (HNFs) 4 and 3, respectively, in these cells. In non-hepatic CV-1 cells, HNF-4 and HNF-3beta activated this minimal enhancer synergistically. This synergy was dependent upon simultaneous binding of these factors to their cognate sites, but it was not due to cooperativity in DNA binding. Separation of these sites by varying helical turns of DNA did not affect simultaneous binding of HNF-3beta and HNF-4 nor did it influence their functional synergy. The synergy was, however, dependent upon the cell type used for functional analysis. In addition, this synergy was further potentiated by estrogen treatment of cells cotransfected with the estrogen receptor. These data indicate that a cell type-restricted intermediary factor jointly recruited by HNF-4 and HNF-3 participates in activation of the apoAI enhancer in liver cells and suggest that the activity of this factor is regulated by estrogen.