Human annexin A6 interacts with influenza a virus protein M2 and negatively modulates infection.

The influenza A virus M2 ion channel protein has the longest cytoplasmic tail (CT) among the three viral envelope proteins and is well conserved between different viral strains. It is accessible to the host cellular machinery after fusion with the endosomal membrane and during the trafficking, assembly, and budding processes. We hypothesized that identification of host cellular interactants of M2 CT could help us to better understand the molecular mechanisms regulating the M2-dependent stages of the virus life cycle. Using yeast two-hybrid screening with M2 CT as bait, a novel interaction with the human annexin A6 (AnxA6) protein was identified, and their physical interaction was confirmed by coimmunoprecipitation assay and a colocalization study of virus-infected human cells. We found that small interfering RNA (siRNA)-mediated knockdown of AnxA6 expression significantly increased virus production, while its overexpression could reduce the titer of virus progeny, suggesting a negative regulatory role for AnxA6 during influenza A virus infection. Further characterization revealed that AnxA6 depletion or overexpression had no effect on the early stages of the virus life cycle or on viral RNA replication but impaired the release of progeny virus, as suggested by delayed or defective budding events observed at the plasma membrane of virus-infected cells by transmission electron microscopy. Collectively, this work identifies AnxA6 as a novel cellular regulator that targets and impairs the virus budding and release stages of the influenza A virus life cycle.

Lead poisoning in new immigrant children from the mainland of China.

OBJECTIVE: To define the prevalence, severity and risk factors for lead poisoning in new immigrant children from the mainland of China to Hong Kong, China. METHODS: New immigrant children from the mainland of China under 18 years of age were invited to join the study. Their growth parameters and venous blood lead levels (BLL) were measured within 7 days of arrival. Those with elevated BLL i.e. > 10 micrograms/dl (0.48 mumol/L) were assessed for signs, symptoms and risk factors of lead poisoning. Education on the prevention of lead poisoning and follow up BLL measurements were offered until their BLL normalized. RESULTS: Four hundred and fifty-seven children were recruited. Among them, 18.1% and 2.6% had BLL > 0.48 and 0.71 mumol/L, respectively. None had BLL > 0.96 mumol/L. Possible risk factors included contaminated drinking water (19%), herb ingestion (17.5%), pica, playing in dumping grounds, residing near paint factories or highways, habitual inhalation of car exhaust and cooking with petroleum. Symptoms and signs included abdominal pain, headache, short stature, and learning difficulties but did not correlate with BLL. None required treatment except for counseling on the avoidance of risk factors. About 94.7% showed a reduction in BLL 2-3 months after arrival and before counseling. All had normalized BLL by 9 months except 1 who had an X-ray feature of lead line. CONCLUSIONS: Lead poisoning is common in new immigrant children from the mainland of China. Environmental factors were most important while behavioral factors like regular herb ingestion might have contributed to the persistence of high BLL in the minority.

Electronic chemical pathology consultation service and dried blood spot metabolic screening in hospital patients.

AIM: Inborn errors of metabolism (IEM) are an unpopular and difficult subject and most clinicians are unfamiliar with them. Although chemical pathologists have a long-standing practice in advising test strategy and result interpretation especially from primary care, such consultations are usually informal, unstructured and those related to IEM are infrequently requested. This study aims to provide a formal electronic consultation service and to apply tandem mass spectrometry-based dried blood spot metabolic screening (DBSM) as a rapid first-line test for patients suspected of IEM. METHODS: DBSM and a chemical pathology consultation were ordered through the hospital computer terminals. DBSM detected 29 metabolic disorders. The clinical data and metabolic results for the 12-month period were reviewed. RESULTS: There were 279 consultations of which 209 were initiated by paediatricians and 70 by adult physicians. The main reasons for consultation were developmental delay, neurological abnormalities, unexplained biochemical abnormalities and monitoring of patients with IEM. There were 158 DBSM requests. One positive case of isovaleric acidaemia was detected. CONCLUSIONS: All high-risk paediatric patients should have a DBSM and a timely electronic chemical pathology consultation as a rapid and cost-effective first-line screening. Provision of a visible, accessible and helpful consultation service enables professional reimbursement.