RNA interference of the clock gene period disrupts circadian rhythms in the expression of genes related to insecticide resistance in the chagas disease vector Triatoma infestans (Hemiptera: Reduviidae).

In Triatoma infestans it was observed pyrethroid resistance attributed in part to an elevated oxidative metabolism mediated by cytochromes P450. The nicotinamide adenine dinucleotide phosphate (NADPH) cytochrome P450 reductase (CPR) plays a crucial role in catalysing the electron transfer from NADPH to all cytochrome P450s. The daily variations in the expression of CPR gene and a P450 gene (CYP4EM7), both associated with insecticide resistance, suggested that their expressions would be under the endogenous clock control. To clarify the involvement of the clock in orchestration of the daily fluctuations in CPR and CYP4M7 genes expression, it was proposed to investigate the effect of silencing the clock gene period (per) by RNA interference (RNAi). The results obtained allowed to establish that the silencing of per gene was influenced by intake schemes used in the interference protocols. The silencing of per gene in T. infestans reduced its expression at all the time points analysed and abolished the characteristic rhythm in the transcriptional expression of per mRNA. The effect of the per gene silencing in the expression profiles at the transcriptional level of CPR and CYP4EM7 genes showed the loss of rhythmicity and demonstrated the biological clock involvement in the regulation of t heir expression.

Replacement of the replication factors of porcine circovirus (PCV) type 2 with those of PCV type 1 greatly enhances viral replication in vitro.

Porcine circovirus type 1 (PCV1), originally isolated as a contaminant of PK-15 cells, is nonpathogenic, whereas porcine circovirus type 2 (PCV2) causes an economically important disease in pigs. To determine the factors affecting virus replication, we constructed chimeric viruses by swapping open reading frame 1 (ORF1) (rep) or the origin of replication (Ori) between PCV1 and PCV2 and compared the replication efficiencies of the chimeric viruses in PK-15 cells. The results showed that the replication factors of PCV1 and PCV2 are fully exchangeable and, most importantly, that both the Ori and rep of PCV1 enhance the virus replication efficiencies of the chimeric viruses with the PCV2 backbone.

Fournier gangrene: first manifestation of occult rectal cancer.

Fournier gangrene is a necrotizing fasciitis of the genital and perineal region. Diverse factors predispose to Fournier gangrene, such as diabetes mellitus, ethylism, liver dysfunction, haematological disorders, obesity or recent regional instrumentation. Rectal tumours can also predispose to Fournier gangrene; most of the reported cases are perforated or unresectable colorectal tumours, but some cases of anorectal cancer diagnosed after recovery from Fournier gangrene have also been reported. In these cases, the presence of a rectal tumour at the time of, or prior to, diagnosis of Fournier gangrene could not be ruled out. We present three cases of rectal cancer whose first manifestation was as Fournier gangrene.

Detection of the genome of Chlamydophila abortus in samples taken from the uteri of 304 sheep at an abattoir.

A PCR was used to detect the genome of Chlamydophila abortus in samples of uterine tissue collected from 304 sheep by a sterile technique at an abattoir. The stage of pregnancy of the sheep was determined by measuring the dimensions of the embryo/fetus, and its morphology was recorded. Only samples from non-pregnant sheep and sheep up to 100 days of gestation were retained; the clinical history of the animals was unknown. The total prevalence of the chlamydial genome was 30.9 per cent, with a significantly higher prevalence in the pregnant animals (46.9 per cent). Higher detection rates were recorded during early gestation than during mid-gestation.

Interferon-gamma induction correlates with protection by DNA vaccine expressing E2 glycoprotein against classical swine fever virus infection in domestic pigs.

Classical swine fever (CSF) is a highly contagious viral infection affecting domestic and wild pigs. For classical swine fever virus (CSFV), immunization with plasmids expressing different versions of glycoprotein E2 has proven an effective way to induce protection. Previously, we have also shown that immunization with DNA vaccine expressing glycoprotein E2 (DNA-E2) induced specific T helper cell responses in the absence of neutralizing antibodies. However, the role of T cell responses in protection against CSFV is largely unknown. Here we have extended these studies to deeply characterize the role of T cell responses by a DNA-E2 and their correlation with protection against CSFV infection. Thus, pigs vaccinated with the DNA vaccine induced a strong cellular immune response, characterized by the specific induction IFN-gamma expressing T cells after vaccination without any detectable levels of CSFV neutralizing antibodies. Constant levels of CSFV-specific IFN-gamma producing cells observed from the beginning of the infection until 7 days after challenge in vaccinated animals might contribute to early control of CSFV replication, at least until neutralizing antibodies are developed. Severe clinical signs of the disease, including high titers of viremia, pyrexia and virus spread to different organs, were recorded in the non-vaccinated challenged animals, in comparison to the vaccinated animals where only one animal showed mild clinical signs and a short peak of viremia. Lack of complete protection in this animal correlated with a delay on the induction of neutralizing antibodies, detectable only from day 11 post-CSFV challenge. Conversely, the rest of the pigs within the group developed neutralizing antibodies as early as at day two post-challenge, correlating with sterile protection. Finally, an inverse correlation seemed to exist between early induction of IFN-alpha and the protection observed, while IL-10 seemed to be differentially regulated in vaccinated and non-vaccinated animals. Our results support the relevance of the induction of a strong T cellular response to confer a solid protection upon DNA vaccination against CSFV. Further experiments are needed to be done in order to clarify the key cytokines playing a role in CSFV-protection and to obtain emergency vaccines capable to confer robust and fast protection.

Chimeric calicivirus-like particles elicit protective anti-viral cytotoxic responses without adjuvant.

We have analyzed the potential of virus-like particles (VLPs) from rabbit hemorrhagic disease virus (RHDV) as a delivery system for foreign T cell epitopes. To accomplish this goal, we generated chimeric RHDV-VLPs incorporating a CD8(+) T cell epitope (SIINFEKL) derived from chicken ovalbumin (OVA). The OVA epitope was inserted in the capsid protein (VP60) of RHDV at two different locations: 1) the N-terminus, predicted to be facing to the inner core of the VLPs, and 2) a novel insertion site predicted to be located within an exposed loop. Both constructions correctly assembled into VLPs. In vitro, the chimeric VLPs activated dendritic cells for TNF-alpha secretion and they were processed and presented to specific T cells. In vivo, mice immunized with the chimeric VLPs without adjuvant were able to induce specific cellular responses mediated by cytotoxic and memory T cells. More importantly, immunization with chimeric VLPs was able to resolve an infection by a recombinant vaccinia virus expressing OVA protein.

The continuous spread of West Nile virus (WNV): seroprevalence in asymptomatic horses.

West Nile virus (WNV) was probably introduced in southern and northern Mexico from the USA in two independent events. Since then, WNV activity has been reported in several Mexican states bordering the USA and the Gulf of Mexico, but disease manifestations seen there in humans and equids are quite different to those observed in the USA. We have analysed WNV seroprevalence in asymptomatic, unvaccinated equids from two Mexican states where no data had been previously recorded. WNV IgG antibodies were detected in 31.6% (91/288) of equine sera from Chiapas and Puebla states (53.3% and 8.0%, respectively). Analysis by plaque reduction neutralization test (PRNT) showed good specificity (99.4%) and sensitivity (84.9%) with the ELISA results. Further analyses to detect antibodies against three different flaviviruses (WNV, St Louis encephalitis virus, Ilheus virus) by haemagglutination inhibition (HI) tests on a subset of 138 samples showed that 53% of the 83 HI-positive samples showed specific reaction to WNV. These data suggest continuous expansion of WNV through Mexico.

Spanish adaptation and validation of the Family Quality of Life Survey.

BACKGROUND: Assessing the quality of life (QOL) for families that include a person with a disability have recently become a major emphasis in cross-cultural QOL studies. The present study examined the reliability and validity of the Family Quality of Life Survey (FQOL) on a Spanish sample. METHOD AND RESULTS: The sample comprised 385 families who were administered the FQOL in Cali, Columbia. The FQOL showed adequate temporal stability (r = 0.68 on Importance and r = 0.78 on Satisfaction) and excellent internal consistency: Cronbach's alpha of 0.96 for Importance and 0.95 for Satisfaction. The confirmatory factor analysis yielded high fit indices, thus confirming that the factor structure of the FQOL as adapted for Spanish people fitted the five-factor model proposed by the survey's authors. CONCLUSIONS: The study provides a valid instrument for the research of the QOL of those families that have a child with a disability within Spanish-speaking community.

[Monocytosis in pediatrics]. / Monocitósis en pediatría.

We report a retrospective survey of monocytosis occurring in children hospitalized at the Hospital Infantil de México. Patients with monocyte count exceeding the mean for age by more than 4 standard deviations were considered to have monocytosis. The cases with monocytosis had more infections than children without monocytosis and those with abscesses were found to have a high frequency of monocytosis. Monocytosis and neutrophilia were frequently associated. Malnutrition was found to have no effect on the frequency of monocytosis. There was no relationship of monocytosis with age, hemoglobin level, lymphocyte count, drugs administered and final outcome. We comment on these findings.