Lessons to be learned from varicella-zoster virus Rentier, Bernard; Piette, Jacques; Baudoux, Laurence ...
Veterinary microbiology,
11/1996, Letnik:
53, Številka:
1
Journal Article, Conference Proceeding, Web Resource
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Varicella-zoster virus (VZV) is an alphaherpesvirus responsible for two human diseases: chicken pox and shingles. The virus has a respiratory port of entry. After two successive viremias, it reaches ...the skin where it causes typical lesions. There, it penetrates the peripheral nervous system and it remains latent in dorsal root ganglia. It is still debatable whether VZV persists in neurons or in satellite cells. During latency, VZV expresses a limited set of transcripts of its immediate early (IE) and early (E) genes but no protein has been detected. Mechanisms of reactivation from ganglia have not been identified. However, dysfunction of the cellular immune system appears to be involved in this process. The cell-associated nature of VZV has made it difficult to identify a temporal order of gene expression, but there appears to be a cascade mechanism as for HSV-1. The lack of high titre cell-free virions or recombination mutants has hindered so far the understanding of VZV gene functions. Five genes, ORFs 4, 10, 61, 62, and 63 that encode regulatory proteins could be involved in VZV latency. ORF4p activates gene promoters with basal activities. ORF10p seems to activate the ORF 62 promoter. ORF61p has trans-activating and trans-repressing activities. The major IE protein ORF62p, a virion component, has DNA-binding and regulatory functions, transactivates many VZV promoters and even regulates its own expression. ORF63p is a nuclear IE protein of yet unclear regulatory functions, abundantly expressed very early in infection. We have established an animal model of VZV latency in the rat nervous system, enabling us to study the expression of viral mRNA and protein expression during latency, and yielding results similar to those found in humans. This model is beginning to shed light on the molecular events in VZV persistent infection and on the regulatory mechanisms that maintain the virus in a latent stage in nerve cells.
Cord blood hematopoietic progenitors undergo circadian and seasonal variations. The lowest values are obtained between 4:00 and 12:00, as well as between May and August. This represents the first ...observation of such rhythms before birth.
Patients expected to need at least three units of blood for their elective cardiovascular or orthopaedic surgery, were allocated randomly to receive intravenous (i.v.) Epoetin alfa 600 IU kg-1 (n = ...27), 300 IU kg-1 (n = 30) or placebo (n = 23), on days 1, 4 and 7. Provided haemoglobin > or = 11 g dL-1, one unit of blood was collected on days 1, 4, 7, 11 and 14. Iron supplementation was given throughout the study. Surgery was scheduled between days 18 and 21. Significantly more patients treated with Epoetin alfa (100% for 600 IU kg-1; 97% for 300 IU kg-1) were able to donate > or = 4 units of blood compared with placebo (78%) (P = 0.011 and P = 0.032). No significant differences were seen in total patient exposure to homologous blood (7.4%, 3.3% and 17.4%, respectively). Mean red cell volume donated (P = 0.005 for 600 IU kg-1; P = 0.158 for 300 IU kg-1 both vs. placebo) and production (P < 0.001 and P = 0.012, respectively) were dose related. Twenty-four patients became iron deficient. No differences in the incidence of adverse events were seen between the groups.
The milk production and its destination in the Masisi zone - North-Kivu Zaire. The abundance of pasture land in the mountainous massif of the Masisi zone, bordering the lake of Kivu, has often amazed ...the tourist or the expert visiting that North eastern part of Zaire. The potential milk production of the area is obvious. Cattle breeding still obeys to very traditional habits, and even farms specializing in milk production, with a capacity of over 2000 horned. Cattle are still run in a quite primitive manner. The cattle feeds on the pasture land of Kikuyu. Whereas the milk produced by minor cattle breeders is used by the locals, a cheese and butter small scale production has developed around the larger farms of Masisi. That production remains however insufficient. No doubt that an improvement of production technics combined with a better organization and better "commercialization" methods would greatly contribue to the evolution of that region in particular, and to production capacities of Zaire in general.
A method of quantitative liver tomoscintigraphy (SPECT) was compared for accuracy with planar scintigraphy (PS) in a group of patients with diffuse alcoholic liver disease. SPECT sensitivity was also ...compared with that of transmission computed tomography (CT), US, aminopyrine breath test (ABT) and liver chemistries (LC). One hundred and fourteen alcoholic patients with proven liver disease and 17 patients free of liver disease were included. Seven quantitative scintigraphic features and a score, including all criteria were considered. With a specificity of 95%, the sensitivity was 79% in steatosis and 97% in cirrhosis. SPECT showed a better sensitivity than PS (SPECT 89%, PS 66%), especially in patients with steatosis. In the same subsets of patients, SPECT sensitivity also compared favorably with that of transmission CT (SPECT 92%, CT 65%), ultrasonography (SPECT 88%, US 53%) and ABT (SPECT 90%, ABT 63%).
Seroprevalence to human immunodeficiency virus (HIV) was determined among 368 children 2 to 14 years of age who were admitted to the pediatric service at Mama Yemo Hospital in Kinshasa, Zaire. Forty ...(11%) of these patients and only one (1%) of 92 healthy siblings of these patients were HIV seropositive (chi 2 = 8.68, P less than .01). Seropositivity was associated with previous hospitalization, receipt of a blood transfusion prior to the current hospitalization (odds ratio 3.1; 95% confidence interval, 1.5 to 6.4), receipt of medical injections during the past year, and smaller household size. Clinically, HIV seropositivity was associated with the diagnoses of malnutrition and pneumonia. A higher proportion of seropositive children died during the current hospitalization (4/40 v 10/328); when patients with malaria were excluded, the in-hospital mortality of seropositive children was more than eight times higher than that of seronegative children (Fisher exact test, P = .006). Clarification of clinical, immunologic, and epidemiologic features of childhood HIV infection is urgently required because HIV appears to account for or complicate a substantial proportion of pediatric hospitalizations in Kinshasa.
A prevalence study of antibody to human immunodeficiency virus (HIV) was conducted in Kinshasa, Zaïre, among 258 children 2-24 months old who were in hospital, 191 children 1-20 months old who were ...attending a well-child clinic, and their mothers. 8% of the mothers of both groups of children were seropositive. Among children under 9 months old, 12 of 102 (12%) hospital inpatients and 11 of 136 (8%) clinic attenders were seropositive, while in the 9-24-month age group 20 of 156 (13%) hospital children and only 1 of 55 (2%) clinic children were seropositive (Fisher's exact test, p = 0.01). 61% of the seropositive children had seropositive mothers, indicating a high rate of vertical transmission. Factors associated with seropositivity among hospital children with seronegative mothers included male sex, increased lifetime number of medical injections, and previous blood transfusion or hospital admission. Among children who had not previously been transfused or admitted to hospital the seropositives had received more medical injections than the seronegatives (median 34.5 versus 14.5; Wilcoxon rank sum test, p = 0.006). HIV infection accounted for or complicated a substantial proportion of hospital paediatric admissions. Public health measures are urgently required to prevent parenteral and vertical transmission of HIV to infants and young children in Kinshasa.
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