Prunus Host Range of Plum pox virus (PPV) in the United States by Aphid and Graft Inoculation.

Plum pox (Sharka) is a serious virus disease of stone fruits caused by the Plum pox virus (PPV). To determine which species could function as potential hosts and virus reservoirs, we used aphid transmission and bud or chip grafting to evaluate the susceptibility of commercial, ornamental, and wild Prunus species to isolates of PPV found in Pennsylvania, USA. Following inoculation, test trees were observed for symptoms, analyzed by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), back-assayed to healthy peach, and followed through at least four cold-induced dormancy (CID) cycles over 4 years. Thirty-one of 33 Prunus species and cultivars were systemically infected following aphid transmission. Systemic infection could not be detected in P. cerasus (sour cherry) and P. × 'Snofozam' (Snow Fountains) despite repeated aphid inoculation attempts. Following grafting of PPV-infected budwood, all 40 species and varieties became infected, although species differed in their susceptibility. Within most species, some individual plants remained PPV negative throughout the study despite repeated inoculations. Infection in some species could be detected only through quantitative reverse transcription (RT)-PCR. Most species displayed clear symptoms, were highly positive by ELISA and RT-PCR, and could be back-inoculated into peach seedlings following CID. Our results indicate that a wide range of native and ornamental Prunus species are susceptible to U.S. isolates of PPV-D.

[Urinary iodine levels within normal range in German school-age children]. / Jodidurie bei Schulkindern in Deutschland 1999 im Normbereich.

BACKGROUND: Recent regional investigations have shown that the abolition of the requirement to declare iodine in foodstuffs and the greater emphasis on information about goitre prevention led to an increase in urinary iodine excretion in Germany. There was also a decrease in thyroid size and goitre prevalence in children. No up to date results for the whole of Germany are available. PROBANDS AND METHODS: In 1999 we examined the urinary iodine excretion in the spontaneous morning urine of 3,065 healthy 6- to 12-year-old school children in 128 places from all over Germany. The iodine was measured by the Cer-arsenit method. RESULTS: The median iodine excretion amounted to 148 micrograms/l. There were no significant differences between age groups, sexes or regions. 73% had no iodine deficiency (> 100 micrograms/l). In 20% the deficiency was slight (50-99 micrograms/l), in 6% moderate (20-49 micrograms/l) and in 1% there was a severe iodine deficiency (< 20 micrograms/l). 8% excreted > 300 micrograms iodide per liter urine. CONCLUSION: According to the WHO guidelines, there is no longer a iodine deficiency in Germany--at least among children prior to puberty.

Continuous rise of urinary iodine excretion and drop in thyroid gland size among adolescents in Mecklenburg-West-Pomerania from 1993 to 1997.

Improved legislation (1989, 1993), as well as education of the public, are likely to improve the iodine supply for the German population. Children and adolescents will be the first to profit. We investigated thyroid size and urinary iodine excretion in a total of 2906 students aged 10 to 18 in Mecklenburg-West-Pomerania in 1993, 1995, and 1997. The median urinary iodine excretion rose from 73 microg/g creatinine in 1993 to 133 microg/g in 1997. The prevalence of goiter, according to the reference range of Gutekunst, dropped from 33% to 10% over the same interval, and the median thyroid size declined from 11 ml to 6 ml. While only 6% of the test subjects excreted more than 150 microg iodine per g creatinine in 1993, this figure rose to 33% in 1997. The improved alimentary iodine supply is due to the increased use of iodine enriched salt by the food industry, food factories and in common food supply services.

Relationship between viral load in blood, cerebrospinal fluid, brain tissue and isolated microglia with neurological disease in macaques infected with different strains of SIV.

The role of the viral burden in the brain for the pathogenesis of human immunodeficiency virus-associated neurological disorders is still unclear. To address this issue, we have quantified the viral load in plasma, cerebrospinal fluid (CSF) and brain tissue of macaques infected with simian immunodeficiency virus (SIV). We discovered that the viral strain used for infection determines the replicative capacity in microglial cells as well as the extent of neuropathological lesions and the occurrence of neurological symptoms. Moreover, the viral load in the brain parenchyma correlated with the development of overt neurological disease whereas the one in plasma did not. By comparing the viral load in three different compartments, we demonstrated that the viral burden in the CSF is influenced both by the viral replication in the periphery as well as in the brain parenchyma. According to these results, it is not the absolute amount of viral load in the CSF but rather the viral antigen contributed by the viral production within the brain which correlates with the development of neurological disease. In longitudinal studies, we observed that this autochthonous virus production, as evidenced by a ratio of the viral load in CSF to the one in plasma, takes place for a prolonged period of time before overt neurological signs are manifested. This finding suggests that this ratio could be used as a prognostic marker for immunodeficiency virus-induced neurological disease.

Protective role of the virus-specific immune response for development of severe neurologic signs in simian immunodeficiency virus-infected macaques.

The pathogenesis of human immunodeficiency virus-associated motor and cognitive disorders is poorly understood. In this context both a protective and a harmful role of the immune system has been discussed. This question was addressed in the present study by correlating the occurrence of neurologic disease in simian immunodeficiency virus (SIV)-infected macaques with disease progression and the humoral and cellular intrathecal antiviral immune response. Overt neurologic signs consisting of ataxia and apathy were observed at a much higher frequency in rapid progressor animals (6 of 12) than in slow progressors (1 of 7). Whereas slow progressors mounted a strong antiviral antibody (Ab) response as evidenced by enzyme-linked immunosorbent and immunospot assays, neither virus-specific Ab titers nor Ab-secreting cells could be found in the cerebrospinal fluid (CSF) or brain parenchyma of rapid progressors. Similarly, increased infiltration of CD8(+) T cells and cytotoxic T lymphocytes specific for viral antigens were detected only in the CSF of slow progressors. The finding that neurologic signs develop frequently in SIV-infected macaques in the absence of an antiviral immune response demonstrates that the immune system does not contribute to the development of motor disorders in these animals. Moreover, the lower incidence of neurologic symptoms in slow progressors with a strong intrathecal immune response suggests a protective role of the virus-specific immunity in immunodeficiency virus-induced central nervous system disease.

[Increased dietary intake of iodine in young people in Mecklenburg-Vorpommern 1993 and 1996]. / Alimentäre Jodaufnahme bei Jugendlichen in Mecklenburg-Vorpommern zwischen 1993 und 1996 gestiegen.

We investigated the goiter prevalence and the urinary iodine excretion of 2,109 young people between 10 and 18 years in the district of Mecklenburg-Vorpommern, Germany in 1995/96. The thyroid volume was determined by ultrasound (7.5 MHz), the iodine excretion by a modified cer-arsenit method. The daily iodine excretion as related to the body surface area and the age related creatinine excretion per 24 h were measured. The results were compared with those of a similar study from 1993 in the same region and the same range of age. The goiter prevalence in 1997 amounted to 18.5%. Among the studied persons 3.6% showed one or more nodules within their thyroid gland. The iodine excretion increased from 70 micrograms in 1993 to 95 micrograms in 1997. There were no changes in the individual nutritional habits (especially iodine-containing foods, using iodized salt etc.). We believe that the raised iodine intake is the result of a higher iodine supply in the commercially produced foodstuffs and animal products due to an increased incorporation of iodine in manufacture of food products.

Lymphocyte subsets and expression of differentiation markers in blood and lymphoid organs of rhesus monkeys.

Rhesus macaques are invaluable experimental animals in biomedical research. Using three color flow cytometry, we screened anti-human antibodies for crossreactivity with macaque cells in order to determine the distribution of functionally important lymphocyte subsets in blood, lymph nodes (LN), and spleen. NK-cells are almost completely absent in LN. The percentage of B-cells expressing CD80, CD86, and the level of expression of CD20 is higher in blood than in LN. In contrast, a higher proportion of B-cells in LN stains positive for CD21 and CD35. Whereas the number of CD29hi expressing T-cells is lower, CD69 is expressed on more T-cells in LN than in blood. About one-third of CD8+ T-cells in blood are CD28-, a subset with a unique pattern of antigen expression which cannot be found in LN. In contrast to humans, a relatively high proportion of T-cells in blood also express the co-stimulatory molecules CD80 and CD86. With increasing age, the proportion of B-cells in blood declines, whereas the percentage of T-cells rises. In addition, the proportion of CD29hi expressing T-cells increases among both the CD4+ and CD8+ subsets.

Regulation of glutathione and cell toxicity following exposure to neurotropic substances and human immunodeficiency virus-1 in vitro.

The aim of the present study was to assess the toxic potential of drugs of abuse and other neuropharmacological agents in the pathogenesis of AIDS dementia complex (ADC), the neurological complication of AIDS. Neuroblastoma and glioblastoma cell lines expressing the dopamine transporter, as well as primary macrophages exposed to human immunodeficiency virus-1 (HIV-1), were used to investigate the possibility of any synergistic effect between the mode of toxicity of such substances and virus exposure. The drugs of abuse used in our experiments were cocaine and morphine, which exert their action, among others, on the dopaminergic system. Effects were compared to treatment with dopamine itself and a typical dopaminergic drug used pharmaceutically, selegiline. In macrophage cultures, glutathione (GSH) was upregulated strongly after treatment with dopamine, morphine or selegiline, and this effect was enhanced when cells were pre-exposed to virus. This upregulation is discussed as a compensatory reaction to an oxidative signal. When hydrogen peroxide plus iron sulfate was used as a strong oxidant in macrophages, GSH concentrations decreased as a result of cell injury. Cell numbers remained constant in all treatment groups. In contrast, in both neuroblastoma and glioblastoma cell lines, the modulation of GSH concentrations by neurotropic substances was accompanied by significant cell loss, which was exacerbated by HIV-1 pretreatment. Selegiline did not change cell numbers when incubated alone. However, when incubated following treatment with HIV-1 cell death was highly significant. Ascorbic acid (AA), included as antioxidant, totally restored cell loss in cultures treated with dopamine. However, no effect was observed in combined treatment of AA and morphine or selegiline. The results demonstrate a synergistic role in cellular toxicity due to neurotropic substances and HIV-1, and suggest that neuropharmacological agents may contribute to the pathogenesis of ADC.

The effect of simian immunodeficiency virus infection in vitro and in vivo on the cytokine production of isolated microglia and peripheral macrophages from rhesus monkey.

Microglia are the major target for human immunodeficiency virus (HIV) infection within the central nervous system. Because only a few cells are productively infected, it has been suggested that an aberrant cytokine production by this cell population may be an indirect mechanism leading to the development of neurological disorders in HIV-infected patients. Therefore we decided to study the secretion pattern of several interleukins (IL) by microglial cells and peripheral blood macrophages isolated from uninfected and simian immunodeficiency virus (SIV)-infected Rhesus monkeys. We found that uninfected, unstimulated primate microglia produce more IL-6 and less TNF alpha than peripheral blood macrophages, but generate comparable levels of IL-1 beta and IL-8. After infection with SIV in vitro, synthesis of all cytokines tested is increased compared to uninfected cultures and to peripheral blood macrophages. Microglia isolated from infected animals produce more IL-8 and TNF alpha than the uninfected cultures and display a strongly increased capacity to secrete TNF alpha upon stimulation with lipopolysaccharide. In addition, production of IL-6 by in vivo-infected microglia increases with time in culture to very high levels despite the fact that only a few cells contained replicating virus. These findings clearly show that the cytokine production of microglia is impaired after SIV infection both in vitro and in vivo and that a low level of viral replication is sufficient for these alterations to occur. In conclusion, the results of this study further support a possible role of cytokines in the pathogenesis of neuro-AIDS.

Murine leukemia virus-induced neurodegeneration of rats: enhancement of neuropathogenicity correlates with enhanced viral tropism for macrophages, microglia, and brain vascular cells.

A highly neuropathogenic retrovirus, NT40, was generated by serially passaging an infectious molecular clone of Friend murine leukemia virus, FB29, through F344 Fisher rats. NT40 induced severe neurological signs such as reflex abnormalities and ataxia within 4-6 weeks following neonatal inoculation. FB29 led to only very mild neurological dysfunctions with longer incubation periods. Pathological alterations were characterized by mild (FB29) to extensive (NT40) noninflammatory spongiform degeneration, mainly of brain-stem areas. Infectious center assays revealed that viral titers in brain tissues of NT40-infected rats were 100-fold higher than those of FB29-infected animals. Employing immunohistochemistry, in situ hybridization, and flow cytometry, NT40 was found to infect many endothelial cells of brain blood vessels and microglia, whereas FB29 infected only microglia and those to a lower extent. However, when isolated from adult diseased rats, microglial cells turned out in both cases to be nonproductively infected with either FB29 or NT40. Of peripheral organs, we found enhanced levels of NT40 in peritoneal macrophages but not in spleen, thymus, or serum when compared to FB29. Altogether these data suggest that an expanded cellular tropism within the CNS and elevated viral titers in macrophages and microglia correlated with enhancement of neuropathogenicity.

Pathology of labial salivary gland cellular aggregates in Sjögren's syndrome.

Sjögren's syndrome (SS) is a chronic autoimmune inflammatory disease in which lymphocytic infiltration of the lacrimal and salivary glands is the hallmark of disease diagnosis. The present study was conducted to identify developmental features of labial salivary gland histopathology to permit earlier diagnosis of SS patients with borderline biopsies. Control subjects were chosen on the basis of clinical presentation consistent with SS, but whose biopsies did not meet current focus score criteria. Intraglandular connective tissue and diffuse cellular infiltration were significantly greater in SS patients than in controls. Glands in both groups had small cellular aggregates (10 to 50 cells/100 microns2), but those in SS patients were more numerous, larger, and contained more lymphocytes, plasma cells, and active fibroblasts. The large inflammatory foci characteristic of SS appeared to be formed by the enlargement and merging of these aggregates. This suggested aggregate formation was the earliest stage of pathology. Therefore, a comprehensive analysis of these cellular aggregates in borderline or negative biopsies could identify at-risk patients and lead to earlier diagnosis and intervention in the disease.

Cancer morbidity rates of children from the vicinity of the nuclear power plant of Würgassen (FRG).

The morbidity rates from neoplastic disease have been studied in children below the age of 15 years, residing at the time of their diagnosis within a diameter of 25 km of the nuclear power plant of Würgassen (FRG). A total of 42 patients were registered between the years of 1980 and 1988: 15 patients with neoplasms of the hematolymphopoietic system, 14 neoplasms of the central nervous system (CNS), and 13 with solid tumors outside of the CNS. The data show that children living in the vicinity of this nuclear power plant do not have an increased risk of developing neoplastic disease, as compared to the entire pediatric population of the FRG. However, a tendency for an elevated risk, not reaching the level of statistical significance, cannot be fully excluded.