Multiple introductions of methicillin-resistant Staphylococcus aureus ST612 into Western Australia associated both with human and equine reservoirs.

Staphylococcus aureus is a serious human and animal pathogen. Multilocus sequence type 612 (ST612) is the dominant methicillin-resistant S. aureus (MRSA) clone in certain South African hospitals and is sporadically isolated from horses and horse-associated veterinarians in Australia. Colonisation and infection by ST612-MRSA is increasing in Western Australia. Whole-genome sequencing was performed for 51 isolates of ST612-MRSA from Western Australian patients and healthcare workers, South African hospital patients, Australian veterinarians and New South Wales horses. Core genome phylogenies suggested that Australian equine and veterinarian-associated ST612-MRSA were monophyletic. Individual Western Australian isolates grouped either with this equine-associated lineage or more diverse lineages related to those in South African hospitals. Bioinformatic analyses of the complete ST612-MRSA reference genome SVH7513 confirmed that ST612-MRSA was closely related to ST8 USA500 MRSA. Common use of rifampicin in South Africa and equine veterinarian practice may favour ST612-MRSA in these settings. Humans and horses colonised with ST612-MRSA are potential reservoirs for MRSA in Australia.

Clinical and genetic profile of congenital long QT syndrome in Hong Kong: a 20-year experience in paediatrics.

INTRODUCTION: Congenital long QT syndrome (LQTS) is a genetically transmitted cardiac channelopathy that can lead to sudden cardiac death. This study aimed to report the clinical and genetic characteristics of all young patients diagnosed with LQTS in the only tertiary paediatric cardiology centre in Hong Kong. METHODS: This is a retrospective review of all paediatric and young adult patients diagnosed at our centre with LQTS from January 1997 to December 2016. The diagnosis of LQTS was established with a corrected QT interval (QTc) ≥480 ms, Schwartz score of >3 points, or the presence of a pathogenic mutation. RESULTS: Fifty-nine patients (33 males) from 52 families were included, with a mean age of 8.17 years (range, 0.00-16.95 years) at presentation. Five patients had concomitant congenital heart diseases. The mean follow-up duration was 5.33 ± 4.65 years. The mean QTc in the cohort was 504 ± 47 ms. They presented with syncope and convulsion (49%), cardiac arrest (10%), bradycardia and neonatal atrioventricular block (12%). Fifteen (25%) patients were asymptomatic at diagnosis. Thirty-eight (64.4%) patients were confirmed to have a pathogenic mutation for LQTS genes. Forty-five (76.3%) patients received beta blocker therapy. Thirteen (22.0%) patients required implantable cardioverter defibrillator. There was no mortality in the study period. The 1-, 5-, and 10-year breakthrough cardiac event-free rates were 93.0%, 80.7%, and 72.6%, respectively. CONCLUSION: Identification of the disorder, administration of beta blockers, and lifestyle modification can prevent subsequent cardiac events in LQTS. Genotyping in patients with LQTS is essential in guiding medical therapy and improving prognosis.

Genetic basis of channelopathies and cardiomyopathies in Hong Kong Chinese patients: a 10-year regional laboratory experience.

INTRODUCTION: Hereditary channelopathies and cardiomyopathies are potentially lethal and are clinically and genetically heterogeneous, involving at least 90 genes. Genetic testing can provide an accurate diagnosis, guide treatment, and enable cascade screening. The genetic basis among the Hong Kong Chinese population is largely unknown. We aimed to report on 28 unrelated patients with positive genetic findings detected from January 2006 to December 2015. METHODS: Sanger sequencing was performed for 28 unrelated patients with a clinical diagnosis of channelopathies or cardiomyopathies, testing for the following genes: KCNQ1,KCNH2,KCNE1,KCNE2, and SCN5A, for long QT syndrome; SCN5A for Brugada syndrome; RYR2 for catecholaminergic polymorphic ventricular tachycardia; MYH7 and MYBPC3 for hypertrophic cardiomyopathy; LMNA for dilated cardiomyopathy; and PKP2 and DSP for arrhythmogenic right ventricular dysplasia/cardiomyopathy. RESULTS: There were 17 males and 11 females; their mean age at diagnosis was 39 years (range, 1-80 years). The major clinical presentations included syncope, palpitations, and abnormal electrocardiography findings. A family history was present in 13 (46%) patients. There were 26 different heterozygous mutations detected, of which six were novel-two in SCN5A (NM_198056.2:c.429del and c.2024-11T>A), two in MYBPC3 (NM_000256.3:c.906-22G>A and c.2105_2106del), and two in LMNA (NM_170707.3:c.73C>A and c.1209_1213dup). CONCLUSIONS: We have characterised the genetic heterogeneity in channelopathies and cardiomyopathies among Hong Kong Chinese patients in a 10-year case series. Correct interpretation of genetic findings is difficult and requires expertise and experience. Caution regarding issues of non-penetrance, variable expressivity, phenotype-genotype correlation, susceptibility risk, and digenic inheritance is necessary for genetic counselling and cascade screening.

TSC1/2 mutations define a molecular subset of HCC with aggressive behaviour and treatment implication.

OBJECTIVE: We investigated the mutational landscape of mammalian target of rapamycin (mTOR) signalling cascade in hepatocellular carcinomas (HCCs) with chronic HBV background, aiming to evaluate and delineate mutation-dependent mechanism of mTOR hyperactivation in hepatocarcinogenesis. DESIGN: We performed next-generation sequencing on human HCC samples and cell line panel. Systematic mutational screening of mTOR pathway-related genes was undertaken and mutant genes were evaluated based on their recurrence. Protein expressions of tuberous sclerosis complex (TSC)1, TSC2 and pRPS6 were assessed by immunohistochemistry in human HCC samples. Rapamycin sensitivity was estimated by colony-formation assay in HCC cell lines and the treatment was further tested using our patient-derived tumour xenograft (PDTX) models. RESULTS: We identified and confirmed multiple mTOR components as recurrently mutated in HBV-associated HCCs. Of significance, we detected frequent (16.2%, n=18/111) mutations of TSC1 and TSC2 genes in the HCC samples. The spectrum of TSC1/2 mutations likely disrupts the endogenous gene functions in suppressing the downstream mTOR activity through different mechanisms and leads to more aggressive tumour behaviour. Mutational disruption of TSC1 and TSC2 was also observed in HCC cell lines and our PDTX models. TSC-mutant cells exhibited reduced colony-forming ability on rapamycin treatment. With the use of biologically relevant TSC2-mutant PDTXs, we demonstrated the therapeutic benefits of the hypersensitivity towards rapamycin treatment. CONCLUSIONS: Taken together, our findings suggest the significance of previously undocumented mutation-dependent mTOR hyperactivation and frequent TSC1/2 mutations in HBV-associated HCCs. They define a molecular subset of HCC having genetic aberrations in mTOR signalling, with potential significance of effective specific drug therapy.

Randomized Trial to Compare Renal Function and Ductal Response between Indomethacin and Ibuprofen Treatment in Extremely Low Birth Weight Infants.

BACKGROUND: A head to head comparison study on renal function and ductal response between indomethacin and ibuprofen has rarely been conducted in extremely low birth weight (ELBW) infants. OBJECTIVES: The aim was to compare renal function and ductal response between indomethacin and ibuprofen in ELBW infants. METHODS: We performed a double-blind randomized control trial to compare renal function and ductal response between indomethacin (0.2, 0.1, and 0.1 mg/kg i.v. every 24 h for 3 doses) and ibuprofen lysine (10, 5, and 5 mg/kg i.v. every 24 h for 3 doses) in ELBW infants with significant hemodynamic patent ductus arteriosus (cardiovascular dysfunction score >3 and LA/AO ratio ≥1.3). RESULTS: A total of 144 infants were enrolled: 73 received indomethacin and 71 received ibuprofen lysine. Significant decreases in urine output were seen in 30 infants (41%) in the indomethacin group and 15 (21%) in the ibuprofen group (p = 0.02). The indomethacin group was associated with a significantly higher chance of persistent ductal response than the ibuprofen group (66 vs. 49%, p = 0.046), but with a lower glomerular filtration rate on day 1, higher serum creatinine on days 1, 2, and 7, and lower urinary prostaglandin on days 2-7. Both groups were comparable in mortality and in bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity morbidity. CONCLUSIONS: With the current dosage, ibuprofen had fewer renal side effects but was associated with a lower rate of persistent ductal closure in ELBW infants. The precise role of prostaglandin on renal tubular function in ELBW infants remains to be further investigated.

Clinical and genetic profile of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children.

OBJECTIVE: To report our experience in the management of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children. METHODS: This case series study was conducted in a tertiary paediatric cardiology centre in Hong Kong. All paediatric patients diagnosed at our centre with catecholaminergic polymorphic ventricular tachycardia from January 2008 to October 2014 were included. RESULTS: Ten patients (five females and five males) were identified. The mean age at presentation and at diagnosis were 11.0 (standard deviation, 2.9) years and 12.5 (2.8) years, respectively. The mean delay time from first presentation to diagnosis was 1.5 (standard deviation, 1.3) years. They presented with recurrent syncope and six patients had a history of aborted cardiac arrest. Four patients were initially misdiagnosed to have epilepsy. Catecholaminergic polymorphic ventricular tachycardia was diagnosed by electrocardiogram at cardiac arrest (n=2), or provocation test, either by catecholamine infusion test (n=6) or exercise test (n=2). Mutations of the RyR2 gene were confirmed in six patients. Nine patients were commenced on beta-blockers after diagnosis. Despite medications, three patients developed aborted or resuscitated cardiac arrest (n=2) and syncope (n=1). Left cardiac sympathetic denervation was performed in five patients and an implantable cardioverter defibrillator was implanted in another. There was no mortality during follow-up. CONCLUSIONS: Catecholaminergic polymorphic ventricular tachycardia should be considered in children who present with recurrent syncope during exercise or emotional stress. Despite beta-blocker treatment, recurrent ventricular arrhythmias occur and may result in cardiac arrest.

Outcomes of accelerated hypofractionated radiotherapy in stage i non-small-cell lung cancer.

PURPOSE: Outcomes after treatment with accelerated hypofractionated radiotherapy in stage i medically inoperable non-small-cell lung cancer (nsclc) patients were determined. METHODS: Our single-institution retrospective review looked at medically inoperable patients with T1-2N0M0 nsclc treated with accelerated hypofractionated curative-intent radiotherapy between 1999 and 2009. Patients were staged mainly by computed tomography imaging of chest and abdomen, bone scan, and computed tomography/magnetic resonance imaging of brain. Positron-emission tomography (pet) staging was performed in 6 patients. Medical charts were reviewed to determine demographics, radiotherapy details, sites of failure, toxicity (as defined by the Common Terminology Criteria for Adverse Events, version 3.0) and vital status. The cumulative incidence of local and distant failure was calculated. Overall (os) and cause-specific (css) survival were estimated by the Kaplan-Meier method. RESULT: In the 60 patients treated during the study period, the dose regimens were 50 Gy in 20 fractions (n = 6), 55 Gy in 20 fractions (n = 8), 60 Gy in 20 fractions (n = 42), and 60 Gy in 25 fractions (n = 4). All patients were treated once daily. The median follow-up was 27 months (range: 4-94 months). The os rates at 2 and 5 years were 61% [95% confidence interval (ci): 50% to 75%] and 19% (95% ci: 10% to 34%) respectively. The css rates at 2 and 5 years were 79% (95% ci: 68% to 91%) and 39% (95% ci: 24% to 63%) respectively. The cumulative incidence of local failure was 20% at 5 years. The cumulative incidence of distant failure was 28% at 5 years. No patients experienced grade 3 or greater pneumonitis or esophagitis. CONCLUSIONS: Accelerated hypofractionated regimens are well tolerated and provide good local control in medically inoperable patients with stage i nsclc. Such regimens may be a reasonable treatment alternative when stereotactic body radiation therapy is not feasible.

HSV IgG antibody inhibits virus detection in CSF.

BACKGROUND: Before PCR testing of cerebrospinal fluid (CSF), laboratory diagnosis of herpes encephalitis (HSE) was based on virus isolation from brain biopsy. Viral isolation from CSF has limited clinical value due to low virus recovery; the cause for which has not been demonstrated. OBJECTIVE: To investigate the role of anti-HSV antibodies on recovery of HSV from CSF via cell culture. STUDY DESIGN: HSV-positive CSF samples were evaluated for their ability to neutralize HSV in cell culture. The presence of HSV-specific IgG and IgM antibodies were analyzed using HSV-infected cells. To identify whether HSV-specific IgG is the cause of viral inhibition, IgG was removed using anti-human IgG magnetic beads. Viral inhibition from CSF originating from asymptomatic patients was examined as a comparison. RESULTS: CSF from 13 patients with acute HSV CNS disease was analyzed. All displayed high levels of viral neutralization to both HSV-1 and HSV-2 regardless of the infecting subtype. Interestingly, all the CSF samples stained strongly for anti-IgG antibody but none for anti-IgM antibody. Removal of IgG from CSF eliminated the viral inhibitory activity. Neutralizing IgG antibody was also found to be common in CSF of most patients, even in the absence of HSV disease. CONCLUSIONS: Viral specific IgG is the major determinant of viral inhibition in CSF and prevents virus recovery in cell culture. In CSF from HSE un-infected patients, viral inhibitory IgG originates from circulating serum antibody and is commonly present in CSF. However, this inhibitory IgG is not protective for the development of HSV disease.

Transcatheter ablation of atrioventricular junctional re-entrant tachycardia in children and adolescents in Hong Kong: comparison of cryothermal with radiofrequency energy.

OBJECTIVE: To compare the outcome of cryothermal and radiofrequency energy transcatheter ablation of atrioventricular junctional re-entrant tachycardia in children and adolescents. DESIGN: Case series with internal comparison. SETTING: Two hospitals in Hong Kong. PATIENTS: Consecutive transcatheter ablation procedures for atrioventricular junctional re-entrant tachycardia in children and adolescents in our unit from August 2000 to September 2008 were retrospectively reviewed. Radiofrequency ablation was performed from August 2000 to June 2005, and cryoablation from July 2005 to September 2008. MAIN OUTCOME MEASURES: Demographic data, outcome and procedural details. RESULTS: Thirty-eight procedures were reviewed. The radiofrequency ablation group (n=20) and cryoablation group (n=18) had similar demographic characteristics, except that there were more patients with congenital heart disease in the latter group (P=0.03). Acute procedural success rate was 100% in both groups. One patient from the radiofrequency ablation group had recurrence of atrioventricular junctional re-entrant tachycardia. The frequency of post-ablation persistent heart block was higher in the radiofrequency ablation than cryoablation group (10% vs 0%, P=0.17), but this difference was not statistically significant. A shorter fluoroscopy time was noted in the cryoablation group (31 ± 13 vs 38 ± 18 minutes; P=0.03). CONCLUSIONS: Transcatheter cryoablation for atrioventricular junctional re-entrant tachycardia in children and adolescents is as effective as radiofrequency ablation over the medium term. It has an excellent safety profile in terms of avoiding heart block.

Influence of country of study on student responsiveness to the H1N1 pandemic.

OBJECTIVES: University students, both travelling abroad on holiday or exchange students entering a country, can serve as mobile carriers of infectious diseases during a pandemic, and thus require special attention when considering preventive measures. The objectives of this study were to evaluate student compliance and opinions on preventive measures of a university before and during an H1N1 influenza pandemic, and to explore environmental and behavioural factors that might contribute towards compliance. STUDY DESIGN: Cross-sectional, self-administered questionnaire. METHODS: Local and foreign students attending an international summer school programme were invited to participate in a self-administered survey. RESULTS: Respondents complied with most of the preventive measures, excluding website viewing and mask wearing. Significant differences in compliance and perceived necessity were found amongst students from Singapore, Hong Kong and the USA. Singaporean students were significantly more likely to comply with all measures and consume antiviral medication in response to the pandemic than students studying in the US. CONCLUSIONS: Students' responses towards university pandemic measures were largely positive, but sensitivity towards these measures varied between groups by country of study. This should be considered in further comparative studies.

Human coronaviruses are uncommon in patients with gastrointestinal illness.

BACKGROUND: Coronaviruses infect numerous animal species causing a variety of illnesses including respiratory, neurologic and enteric disease. Human coronaviruses (HCoV) are mainly associated with respiratory tract disease but have been implicated in enteric disease. OBJECTIVES: To investigate the frequency of coronaviruses in stool samples from children and adults with gastrointestinal illness by RT-PCR. STUDY DESIGN: Clinical samples submitted for infectious diarrhea testing were collected from December 2007 through March 2008. RNA extraction and RT-PCR was performed for stools negative for Clostridium difficile using primer sets against HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1. Clinical data from samples positive for coronaviruses were reviewed and recorded. RESULTS: Samples from 479 patients were collected including 151 pediatric (< or = 18 years), and 328 adults (>18 years). Of these samples, 4 patients (1.3%, 2 adult; 2 pediatric) screened positive for the presence of a coronavirus. All detected coronaviruses were identified as HCoV-HKU1. No stools screened positive for either HCoV-229E, HCoV-NL63 or HCoV-OC43. All HCoV-HKU1 positive samples occurred between mid-January to mid-February. Clinical manifestations from HCoV-HKU1 positive patients included diarrhea, emesis and respiratory complaints. Three (75%) patients were admitted to the hospital with a median length of stay of 6 days. CONCLUSIONS: Coronaviruses as a group are not commonly identified in stool samples of patients presenting with gastrointestinal illness. HCoV-HKU1 can be identified in stool samples from children and adults with gastrointestinal disease, with most individuals having respiratory findings as well. No stool samples screened positive for HCoV-NL63, HCoV-229E, or HCoV-OC43.

Monoclonal antibodies to VP1 recognize a broad range of enteroviruses.

Enteroviruses (EVs) are common seasonal viruses that are associated with a variety of diseases. High-quality monoclonal antibodies (MAbs) are needed to improve the accuracy of EV diagnosis in clinical laboratories. In the present study, the full-length VP1 genes of poliovirus 1 (Polio 1) and coxsackievirus B3 (Cox B3) were cloned, and the encoded proteins were expressed and used as antigens in an attempt to raise broad-spectrum MAbs to EVs. Two pan-EV MAbs were isolated: one raised against Polio 1 VP1 and the other against Cox B3 VP1. The binding sites of both pan-EV MAbs were mapped to an amino acid sequence within a conserved region in the N terminus of Polio 1 VP1 by peptide and competition enzyme-linked immunosorbent assay. Two additional MAbs, an EV70-specific MAb and an EV71/Cox A16-bispecific MAb, developed against EV70 and 71 VP1 proteins, were pooled with the two pan-EV MAbs (pan-EV MAb mix) and tested for their sensitivity and specificity in the staining of various virus-infected cells. The pan-EV MAb mix detected all 40 prototype EVs tested and showed no cross-reactivity to 18 different non-EV human viruses. Compared with two commercially available EV tests, the pan-EV MAb mix exhibited higher specificity than one test and broader spectrum reactivity than the other. Thus, our study demonstrates that full-length Polio 1 VP1 and Cox B3 VP1 can serve as effective antigens for developing a pan-EV MAb and that the pan-EV MAb mix can be used for the laboratory diagnosis of a wide range of EV infections.

Excretion of human immunodeficiency virus type 1 through polarized epithelium by immunoglobulin A.

Human immunodeficiency virus (HIV) is transmitted primarily sexually across mucosal surfaces. After infection, HIV propagates initially in the lamina propria below the polarized epithelium and causes extensive destruction of mucosal T cells. Immunoglobulin A (IgA) antibodies, produced in the lamina propria and then transcytosed across the mucosal epithelium into the lumen, can be the first line of immune defense against HIV. Here, we used IgA monoclonal antibodies against HIV envelope proteins to investigate the abilities of polarized primate and human epithelial cells to excrete HIV virions from the basolateral to the apical surface via polymeric Ig receptor (pIgR)-mediated binding and the internalization of HIV-IgA immune complexes. African green monkey kidney cells expressing pIgR demonstrated HIV excretion that was dependent on the IgA concentration and the exposure time. Matched IgG antibodies with the same variable regions as the IgA antibodies and IgA antibodies to non-HIV antigens had no HIV excretory function. A mixture of two IgA anti-bodies against gp120 and gp41 showed a synergistic increase in the level of HIV excreted. The capacity for HIV excretion correlated with the ability of IgA antibodies to bind HIV and of the resulting immune complexes to bind pIgR. Consistent with the epithelial transcytosis of HIV-IgA immune complexes, the colocalization of HIV proteins and HIV-specific IgA was detected intracellularly by confocal microscopy. Our results suggest the potential of IgA antibodies to excrete HIV from mucosal lamina propria, thereby decreasing the viral burden, access to susceptible cells, and the chronic activation of the immune system.

Evidence of human bocavirus circulating in children and adults, Cleveland, Ohio.

BACKGROUND: Viral respiratory illness is a major cause of morbidity and mortality. The human bocavirus (HBoV) is a recently recognized parvovirus isolated from human respiratory secretions. OBJECTIVES: To define the clinical and epidemiologic characteristics in adult and pediatric patients with evidence of HBoV. STUDY DESIGN: From October 2005 through October 2006, we screened respiratory samples from children and adults negative for common respiratory pathogens for HBoV by PCR. Demographic and clinical characteristics were obtained from medical records of HBoV positive individuals. RESULTS: Of 2075 samples screened, 1826 (88.0%) represented distinct respiratory events: 1539 (84.3%) were pediatric (<18 years), and 273 (15.0%) adult (> or =18 years). Forty (2.2%) patients had HBoV: 36 (2.3%) children and 4 (1.5%) adults. HBoV positive children had history of prematurity (31.3%) and cardiac disease (18.8%). Adults had underlying pulmonary (100%) and cardiac (50%) disease. Twenty-seven children (84.4%) were hospitalized; 9 (28.1%) required intensive care. All adults were hospitalized; none required intensive care. Nosocomial acquisition likely occurred in 3 patients. CONCLUSIONS: HBoV circulates in Cleveland, OH, in children and adults with similar frequencies, and can warrant hospitalization and intensive care. Further study would clarify our understanding of this newly recognized human pathogen.

CK2 mediates phosphorylation and ubiquitin-mediated degradation of the PML tumor suppressor.

The PML tumor suppressor controls growth suppression, induction of apoptosis, and cellular senescence. PML loss occurs frequently in hematopoietic and solid tumors. PML loss often correlates with tumor progression. Casein kinase 2 (CK2) is a stress-activated serine/threonine protein kinase that is oncogenic and frequently overexpressed in human tumor of multiple histological origins. In addition, CK2 overexpression due to gene amplification has been reported to be an adverse prognostic factor in non-small cell lung cancer. At the 5th International Conference on Protein Kinase CK2 in Padova, Italy, we reviewed our recent findings that PML undergoes ubiquitin/proteasome-mediated degradation in immortalized and tumor derived cell lines. PML degradation depends on direct CK2 phosphorylation of PML Ser517. PML mutants that are resistant to CK2 phosphorylation display increased tumor suppressive functions in assays measuring apoptosis, replicative senescence, and in xenograft models. More significantly, CK2 pharmacological inhibition enhances PML tumor suppressive property. These data identify a key post-translational mechanism that controls PML protein levels in cancer cells and suggest that CK2 inhibitors may be beneficial anti-cancer drugs.

Calu-3/A-549 mixed cells as a replacement for primary rhesus monkey kidney cells for virus detection.

BACKGROUND: Primary kidney cells derived from rhesus macaques (pRhMK) are heavily relied upon for the detection and culture of a wide range of clinically relevant viruses. The use of these cultures is problematic due to the possible presence of endogenous viruses, the need to sacrifice a primate, and the inherent variance found in primary cultures. OBJECTIVE: To develop a continuous cell line or mixed cell co-culture that could replace dependence on pRhMK cells. STUDY DESIGN: Cells from the Calu-3 and A-549 cell lines were used to prepare mixed cell monolayers that were compared to pRhMK cells for their ability to detect respiratory viruses, measles, mumps, enteroviruses, and herpes viruses. Clinically derived and laboratory virus strains were used for these comparisons in culture plates or 16 mm tubes. RESULTS: Calu-3/A-549 cells are more sensitive than pRhMK for the detection of adenovirus, enteroviruses and herpes simplex virus and are about equally sensitive for the detection of other respiratory viruses, measles, mumps and varicella-zoster virus. CONCLUSIONS: Calu-3/A-549 cells are an equivalent or better alternative to pRhMK cells for the detection of many clinically relevant viruses.

Immunoglobulin A antibodies against internal HIV-1 proteins neutralize HIV-1 replication inside epithelial cells.

We show that intraepithelial cell neutralization of HIV by IgA antibodies to internal viral proteins can occur during antibody transcytosis from the basolateral to the apical surface. Polarized epithelial cells expressing the polymeric immunoglobulin receptor (pIgR) were transfected with HIV proviral DNA, and IgA was added to the basolateral side. Transcytosing IgA antibodies against Gag and RT significantly inhibited HIV replication as assessed by infection of HeLa-CD4-LTR/beta-Gal cells and direct p24 assay. Consistent with intracellular neutralization, colocalization of the internal virus proteins and their IgA antibodies was demonstrated by confocal microscopy. Thus, at least in the context of infections of polarized epithelia, antibody-mediated neutralization may not be restricted to viral surface antigens.

Abolishing Bax-dependent apoptosis shows beneficial effects on spinal muscular atrophy model mice.

Spinal muscular atrophy (SMA) is the most common genetic motoneuron degenerative disorder, but the mechanism(s) of motoneuron degeneration is unclear. We previously generated SMA model mice, which genotypically and phenotypically mimicked human SMA patients, by a combination of knockout and transgenic techniques. Here, we used these SMA model mice to decipher the apoptotic mechanism(s) involved in SMA motoneuron degeneration. We found a significant increase in proapoptotic Bax expression in the spinal cords of SMA mice in comparison with their wild-type littermates. After crossing SMA mice with Bax knockout mice, we produced in vivo evidence indicating that Bax protein plays an important role in the degeneration of SMA spinal motoneurons. Progeny Bax-deficient SMA mice showed milder disease severity, longer life spans, and significant increases in spinal motoneuron densities compared to SMA littermates with wild-type Bax genes. Our results strongly suggest that suppression of Bax-involved apoptosis has the potential for amelioration of SMA.