Impaired development of neural-crest cell-derived organs and intellectual disability caused by MED13L haploinsufficiency

MED13L is a component subunit of the Mediator complex, an important regulator of transcription that is highly conserved across eukaryotes. Here, we report MED13L disruption in a translocation t(12;19) breakpoint of a patient with Pierre-Robin syndrome, moderate intellectual disability, craniofacial anomalies, and muscular defects. The phenotype is similar to previously described patients with MED13L haploinsufficiency. Knockdown of MED13L orthologue in zebrafish, med13b, showed early defective migration of cranial neural crest cells (NCCs) that contributed to cartilage structure deformities in the later stage, recapitulating craniofacial anomalies seen in human patients. Notably, we observed abnormal distribution of developing neurons in different brain regions of med13b morphant embryos, which could be rescued upon introduction of full-length human MED13L mRNA. To compare with mammalian system, we suppressed MED13L expression by short-hairpin RNA in ES-derived human neural progenitors, and differentiated them into neurons. Transcriptome analysis revealed differential expression of components of Wnt and FGF signaling pathways in MED13L-deficient neurons. Our finding provides a novel insight into the mechanism of overlapping phenotypic outcome targeting NCCs derivatives organs in patients with MED13L haploinsufficiency, and emphasizes a clinically recognizable syndromic phenotype in these patients.

Locked pubic symphysis into the obturator foramen: a rare case presentation and literature review

Locked pubic symphysis is a rare form of pelvic injury. It occasionally occurs after a lateral compression injury of the pelvis. We described an overlapping pubic symphysis dislocation that was locked into the contralateral obturator foramen. To the best of our knowledge, there are about seventeen similar cases reported in the literature. The pubic symphysis was finally reduced by means of a superior pubic ramus osteotomy to unlock the incarcerated pubic body out of the contralateral obturator foramen. As the reduction was unstable, the pubic symphysis was fixed with a reconstruction plate. The patient recovered completely and returned to normal activities within 4months. At 1year's follow-up she reported no discomfort in the pubic symphysis region and was able to void urine normally.

Patterns of gene transcript abundance in the blood of children with severe or uncomplicated dengue highlight differences in disease evolution and host response to dengue virus infection

DNA microarrays and specific reverse-transcription polymerase chain reaction assays were used to reveal transcriptional patterns in the blood of children presenting with dengue shock syndrome (DSS) and well-matched patients with uncomplicated dengue. The transcriptome of patients with acute uncomplicated dengue was characterized by a metabolically demanding "host-defense" profile; transcripts related to oxidative metabolism, interferon signaling, protein ubiquination, apoptosis, and cytokines were prominent. In contrast, the transcriptome of patients with DSS was surprisingly benign, particularly with regard to transcripts derived from apoptotic and type I interferon pathways. These data highlight significant heterogeneity in the type or timing of host transcriptional immune responses precipitated by dengue virus infection independent of the duration of illness. In particular, they suggest that, if transcriptional events in the blood compartment contribute to capillary leakage leading to hypovolemic shock, they occur before cardiovascular decompensation, a finding that has implications for rational adjuvant therapy in this syndrome.

Comparative analytical sensitivities of six rapid influenza A antigen detection test kits for detection of influenza A subtypes H1N1, H3N2 and H5N1

BACKGROUND

Rapid and simple methods for diagnosing human influenza A (H5N1) disease urgently needed. The limited data so far suggest that the currently available rapid antigen detection kits have poor clinical sensitivity for diagnosis of human H5N1 disease.

OBJECTIVES

To compare the analytical sensitivity of six commercially available rapid antigen detection kits for the detection of "human" (subtypes H1N1, H3N2) and "avian" (subtype H5N1) influenza A viruses.

STUDY DESIGN

Six commercially available test kits for the detection of influenza A were investigated. Analytic sensitivity for the detection of two contemporary H1N1, two H3N2 and three H5N1 viruses was determined using virus culture as a reference method.

RESULTS AND CONCLUSIONS

Each test kit detected the H5N1 virus subtypes as efficiently as they detected conventional human viruses of subtypes H1N1 or H3N2. However, limits of detection of influenza viruses of all subtypes by antigen detection kits were >1000-fold lower than virus isolation. Thus, the reportedly poor clinical sensitivity of these antigen detection kits for diagnosis of patients with H5N1 disease is not due to a difference of sensitivity for detecting avian influenza H5N1 compared to human influenza viruses.

Proinflammatory cytokine responses induced by influenza A (H5N1) viruses in primary human alveolar and bronchial epithelial cells

Background

Fatal human respiratory disease associated with influenza A subtype H5N1 has been documented in Hong Kong, and more recently in Vietnam, Thailand and Cambodia. We previously demonstrated that patients with H5N1 disease had unusually high serum levels of IP-10 (interferon-gamma-inducible protein-10). Furthermore, when compared with human influenza virus subtype H1N1, the H5N1 viruses in 1997 (A/Hong Kong/483/97) (H5N1/97) were more potent inducers of pro-inflammatory cytokines (e.g. tumor necrosis factor-a) and chemokines (e.g. IP-10) from primary human macrophages in vitro, which suggests that cytokines dysregulation may play a role in pathogenesis of H5N1 disease. Since respiratory epithelial cells are the primary target cell for replication of influenza viruses, it is pertinent to investigate the cytokine induction profile of H5N1 viruses in these cells.

Methods

We used quantitative RT-PCR and ELISA to compare the profile of cytokine and chemokine gene expression induced by H5N1 viruses A/HK/483/97 (H5N1/97), A/Vietnam/1194/04 and A/Vietnam/3046/04 (both H5N1/04) with that of human H1N1 virus in human primary alveolar and bronchial epithelial cells in vitro.

Results

We demonstrated that in comparison to human H1N1 viruses, H5N1/97 and H5N1/04 viruses were more potent inducers of IP-10, interferon beta, RANTES (regulated on activation, normal T cell expressed and secreted) and interleukin 6 (IL-6) in primary human alveolar and bronchial epithelial cells in vitro. Recent H5N1 viruses from Vietnam (H5N1/04) appeared to be even more potent at inducing IP-10 than H5N1/97 virus.

Conclusion

The H5N1/97 and H5N1/04 subtype influenza A viruses are more potent inducers of proinflammatory cytokines and chemokines in primary human respiratory epithelial cells than subtype H1N1 virus. We suggest that this hyper-induction of cytokines may be relevant to the pathogenesis of human H5N1 disease.

Are ducks contributing to the endemicity of highly pathogenic H5N1 influenza virus in Asia?

Wild waterfowl are the natural reservoir of all influenza A viruses, and these viruses are usually nonpathogenic in these birds. However, since late 2002, H5N1 outbreaks in Asia have resulted in mortality among waterfowl in recreational parks, domestic flocks, and wild migratory birds. The evolutionary stasis between influenza virus and its natural host may have been disrupted, prompting us to ask whether waterfowl are resistant to H5N1 influenza virus disease and whether they can still act as a reservoir for these viruses. To better understand the biology of H5N1 viruses in ducks and attempt to answer this question, we inoculated juvenile mallards with 23 different H5N1 influenza viruses isolated in Asia between 2003 and 2004. All virus isolates replicated efficiently in inoculated ducks, and 22 were transmitted to susceptible contacts. Viruses replicated to higher levels in the trachea than in the cloaca of both inoculated and contact birds, suggesting that the digestive tract is not the main site of H5N1 influenza virus replication in ducks and that the fecal-oral route may no longer be the main transmission path. The virus isolates' pathogenicities varied from completely nonpathogenic to highly lethal and were positively correlated with tracheal virus titers. Nevertheless, the eight virus isolates that were nonpathogenic in ducks replicated and transmitted efficiently to naïve contacts, suggesting that highly pathogenic H5N1 viruses causing minimal signs of disease in ducks can propagate silently and efficiently among domestic and wild ducks in Asia and that they represent a serious threat to human and veterinary public health.

Role of domestic ducks in the propagation and biological evolution of highly pathogenic H5N1 influenza viruses in Asia

Wild waterfowl, including ducks, are natural hosts of influenza A viruses. These viruses rarely caused disease in ducks until 2002, when some H5N1 strains became highly pathogenic. Here we show that these H5N1 viruses are reverting to nonpathogenicity in ducks. Ducks experimentally infected with viruses isolated between 2003 and 2004 shed virus for an extended time (up to 17 days), during which variant viruses with low pathogenicity were selected. These results suggest that the duck has become the "Trojan horse" of Asian H5N1 influenza viruses. The ducks that are unaffected by infection with these viruses continue to circulate these viruses, presenting a pandemic threat.

Assessment of synthetic peptides of severe acute respiratory syndrome coronavirus recognized by long-lasting immunity

Abstract:  In order to determine highly immunogenic severe acute respiratory syndrome coronavirus (SARS‐CoV) epitope peptides capable of inducing long‐lasting immunity, we first screened immunoglobulin‐G (IgG) antibodies reactive to 197 different overlapping 15‐mers from the SARS‐CoV proteins in the sera of three infected patients. Forty‐two peptides among them were reactive to the sera from all three patients. Consequently, we tested for the reactivity of these 42 peptides to patients' sera (n = 45) at 6‐month post‐infection. The significantly higher levels of IgG antibodies specific to three (S791, M207 and N161) of 42 peptides were detectable in the post‐infection sera from 23 (51%), 27 (60%) and 19 (42%) of 45 patients, respectively. These three peptides, recognized by their long‐lasting immunity, may provide a better understanding of the immunogenicity of SARS‐CoV.

Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia

A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks in poultry in China and seven other east Asian countries between late 2003 and early 2004; the same virus was fatal to humans in Thailand and Vietnam. Here we demonstrate a series of genetic reassortment events traceable to the precursor of the H5N1 viruses that caused the initial human outbreak in Hong Kong in 1997 (refs 2-4) and subsequent avian outbreaks in 2001 and 2002 (refs 5, 6). These events gave rise to a dominant H5N1 genotype (Z) in chickens and ducks that was responsible for the regional outbreak in 2003-04. Our findings indicate that domestic ducks in southern China had a central role in the generation and maintenance of this virus, and that wild birds may have contributed to the increasingly wide spread of the virus in Asia. Our results suggest that H5N1 viruses with pandemic potential have become endemic in the region and are not easily eradicable. These developments pose a threat to public and veterinary health in the region and potentially the world, and suggest that long-term control measures are required.

HIV in Vietnam: the evolving epidemic and the prevention response, 1996 through 1999

OBJECTIVES

To describe epidemiologic patterns and trends in HIV infection in Vietnam from 1996 through 1999, and to summarize the national response to the epidemic.

METHODS

We reviewed nationwide HIV case reports, and we analyzed annual seroprevalence among different sentinel populations in 21 provinces, using the chi2 test for linear trend to assess trends in HIV prevalence. HIV prevention efforts were also reviewed.

RESULTS

Through 1999, 17,046 HIV infections, including 2947 AIDS cases and 1523 deaths had been reported in Vietnam. The cumulative incidence rate for the country was 22.5 per 100,000 population. Injection drug users (IDUs) represented 89.0% of all those for whom risk was reported before 1997 and 88.0% in the period 1997 to 1999. In 1999, HIV prevalence rates among IDUs ranged by province from 0% to 89.4%. Significantly increasing HIV trends among IDUs (p <.05) were found in 14 of the 21 sentinel provinces during 1996 to 1999. HIV prevalence among commercial sex workers (CSWs) ranged from 0% to 13.2%, increased significantly in 6 of 21 provinces. In 1999, prevalence among pregnant women, blood donors, and military recruits were 0.12%, 0. 20% and 0.61%, respectively. Major prevention activities include mass information; peer education and outreach among groups at increased risk; availability of low-cost syringes and condoms through pharmacies; needle exchange pilot projects; widely available treatment for sexually transmitted diseases; antibody screening of blood for transfusion; and free medical treatment at government hospitals.

DISCUSSION

The HIV epidemic continues to evolve rapidly, intensifying among IDUs and increasing among CSWs. Serosurveillance indicators of HIV in the population at large continue to indicate the relatively slow extension beyond those at highest risk. Immediate, intensive preventions in high-risk groups may decelerate expansion to the broader population.

Sequence and phylogenetic analyses of HIV-1 infection in Vietnam: subtype E in commercial sex workers (CSW) and injection drug users (IDU)

More than 4,000 persons with human immunodeficiency virus type 1 (HIV-1) infection have been identified in Vietnam through sentinel surveillance since 1990, when the first case of HIV-1 infection was diagnosed in a young woman in Ho Chi Minh City. Currently, the estimated HIV-1 seroprevalences of 10% for injection drug users (IDU) and 3% for female commercial sex workers (CSW) in Vietnam are comparable to those observed in the same risk groups in Thailand five years ago. To clarify if concurrent epidemics with different HIV-1 subtypes (or clades) are occurring among different high-risk behavior groups in Vietnam, we conducted a genotypic analysis of HIV-1 by amplifying and sequencing a 325-nucleotide region spanning the principal neutralizing domain, or V3 loop, of the gp120-encoding env gene from genomic DNA extracted from dried, filter paper-blotted blood samples, collected in April/May and August/September 1995 from 8 HIV-1-seropositive CSW in Ho Chi Minh City, Can Tho and An Giang provinces and from 16 IDU in Ho Chi Minh City, Hanoi, Nha Trang and An Giang province. Sequence alignment and comparison with other HIV-1 subtypes indicated that the HIV-1 strains from CSW and IDU in Vietnam were genetically most similar to subtype E strains from Cambodia. The interstrain genetic variation among the Vietnam HIV-1 env sequences ranged from 0.3% to 9.0% (mean, 4.6%). Phylogenetic analysis verified that some of the Vietnam HIV-1 strains formed discrete clusters and were indistinguishable from other Southeast Asian strains. The demonstration of subtype E in both CSW and IDU in Vietnam contrasts sharply with the previously observed HIV-1 clade restriction in these high-risk behavior groups in nearby Thailand.

Skin test responsiveness to a series of new tuberculins of children living in three Vietnamese cities

A skin test survey was conducted among 1035 children aged 7-19 years living in three cities in Vietnam. Fifteen new tuberculins, including leprosin-A, were applied; an induration of 2 mm diameter or more was considered positive. Compared to some other tropical countries, low levels of sensitisation were recorded and remarkable regional differences were found. Positivity to any tuberculins (pooled data) among non-BCG-vaccinated children was significantly lower in Hanoi (13.1%) and HoChiMinh-City [HCMC] (15.5%) than in Nha Trang (25.7%) [p = 0.001 and p = 0.012, respectively]. The proportion of non-vaccinated children responding to Tuberculin ranged from 18.4% in Hanoi to 54.5% in Nha Trang. Leprosin-A elicited a response in 14.9% of the children in Nha Trang, but in very few of those in Hanoi (4.3%) or HCMC (3.0%). Thus, of the three cities studied, significant sensitisation to both M. tuberculosis and M. leprae was demonstrable only in Nha Trang. In Hanoi most of the response was to fast-growing species whilst in HCMC and Nha Trang it was mainly to slow-growing species. These results may account in part for the observed differences in the prevalence of tuberculosis and leprosy between the north and the south of Vietnam.

Responses to Mycobacterium leprae by lymphocytes from new and old leprosy patients: role of exogenous lymphokines

Lepromatous leprosy patients generally have reduced response to Mycobacterium leprae antigens in an in vitro lymphocyte transformation test, which could be due to insufficient generation of reactions or to active suppression of any reaction generated. We could detect 3 types of lack of reactivity: one which could be restored by the addition of supernatants from healthy, PHA-stimulated lymphocyte cultures, one which could not thus be restored and one in which the culture supernatant contained factors able to suppress mitogen responses of healthy cells. We compared responses of cells from untreated patients, patients treated for 12-20 months with multiple drug therapy and patients with up to 20 years of dapsone treatment; all types of the disease were represented. Untreated patients of all types had low responses which were not always reconstituted by lymphokine-rich supernatants, but they did not produce the non-specific soluble suppressive factors. In most cases, including BL/LL types, after the initial months of treatment, antigen response improved and was further increased by the addition of supernatants containing lymphokines. Most of the long-term-treated, stable patients had a lymphokine-reconstitutable antigen response, and in most cases also produced non-specific suppressive factor(s). The question as to why leprosy patients do not respond to M. leprae antigen is a complex one; our results suggest that it is related to the activity of the infection in each group of patients.