The 23-valent polysaccharide pneumococcal vaccination is not useful in BMT patients at risk of pneumococcal bacteremic sepsis

published_or_final_versio

Identification of novel porcine and bovine parvoviruses closely related to human parvovirus 4

Human parvovirus 4 (PARV4), a recently discovered parvovirus found exclusively in human plasma and liver tissue, was considered phylogenetically distinct from other parvoviruses. Here, we report the discovery of two novel parvoviruses closely related to PARV4, porcine hokovirus (PHoV) and bovine hokovirus (BHoV), from porcine and bovine samples in Hong Kong. Their nearly full-length sequences were also analysed. PARV4-like viruses were detected by PCR among 44.4% (148/333) of porcine samples (including lymph nodes, liver, serum, nasopharyngeal and faecal samples), 13% (4/32) of bovine spleen samples and 2% (7/362) of human serum samples that were sent for human immunodeficiency virus and hepatitis C virus antibody tests. Three distinct parvoviruses were identified, including two novel parvoviruses, PHoV and BHoV, from porcine and bovine samples and PARV4 from humans, respectively. Analysis of genome pequences from seven PHoV strains, from three BHoV strains and from one PARV4 strain showed that the two animal parvoviruses were most similar to PARV4 with 61.5-63% nt identities and, together with PARV4 (HHoV), formed a distinct cluster within the family Parvoviridae. The three parvoviruses also differed from other parvoviruses by their relatively large predicted VP1 protein and the presence of a small unique conserved putative protein. Based on these results, we propose a separate genus, Hokovirus, to describe these three parvoviruses. The co-detection of porcine reproductive and respiratory syndrome virus, the agent associated with the recent 'high fever' disease outbreaks in pigs in China, from our porcine samples warrants further investigation. © 2008 SGM.published_or_final_versio

Myosin VI in PC12 cells plays important roles in cell migration and proliferation but not in catecholamine secretion

Myosin VI (MVI) is the only known myosin walking towards minus end of actin filaments and is believed to play distinct role(s) than other myosins. We addressed a role of this unique motor in secretory PC12 cells, derived from rat adrenal medulla pheochromocytoma using cell lines with reduced MVI synthesis (produced by means of siRNA). Decrease of MVI expression caused severe changes in cell size and morphology, and profound defects in actin cytoskeleton organization and Golgi structure. Also, significant inhibition of cell migration as well as cell proliferation was observed. Flow cytometric analysis revealed that MVI-deficient cells were arrested in G0/G1 phase of the cell cycle but did not undergo increased senescence as compared with control cells. Also, neither polyploidy nor aneuploidy were detected. Surprisingly, no significant effect on noradrenaline secretion was observed. These data indicate that in PC12 cells MVI is involved in cell migration and proliferation but is not crucial for stimulation-dependent catecholamine release

A tissue-specific exon of Myosin Va is responsible for selective cargo binding in melanocytes

Class V myosins are molecular motors used for intracellular transportation and organelle tethering. The mouse Myosin Va (MyoVa) is encoded by the dilute locus, which is alternatively spliced to generate several tissue specific isoforms. The tail of MyoVa is the putative cargo-binding domain. To determine the functions of different isoforms of MyoVa and the minimal cargo-binding region, we tagged various isoforms and different portions of the mouse MyoVa tail with a green fluorescent protein and examined their intracellular localizations in the mouse melan-a cells. We found that the amino acid sequence encoded by an alternatively spliced exon, exon F, is necessary for the selective binding of MyoVa to melanosome. The MyoVa isoforms lacking this amino acid sequence are not targeted to the melanosomes, but localized to the perinuclear region instead. These findings suggested that MyoVa is able to bind to more than one types of cargos, with the selectivities determined by alternative spliced sequences. © 2002 Wiley-Liss, Inc.link_to_subscribed_fulltex

Life-threatening cryoglobulinemia in HCV-negative Southern Chinese and a novel association with structural aortic abnormalities

Cryoglobulinemia is uncommon in Southern Chinese in Hong Kong, with tropical climates and low incidence of hepatitis C virus (HCV) infection. Eight positive cases were detected among 481 patients screened for cryoglobulins over a 10-year period. Three HCV carriers (38%) ran benign courses. The others included two carriers of hepatitis B virus (HBV), two patients with adenocarcinoma, and one with chronic lymphocytic lymphoma. Four of them (except one HBV carrier) ran fulminant courses and died of cryoglobulin-related complications. Interestingly, all four cases also had structural aortic abnormalities, including multiple dissections, aneurysms, and congenital aortic arch abnormalities, which were often life threatening. The association of aortic abnormality and cryoglobulinemia is hitherto unreported and may be peculiar to our ethnic group. Aggressive control of the cryoglobulin may help to reduce aortic intima damage. © Springer-Verlag 2005.link_to_subscribed_fulltex

The 23-valent polysaccharide pneumococcal vaccination is not useful in BMT patients at risk of pneumococcal bacteremic sepsis

Poster Presentation: no. P1