香港的選擇性墮胎: 合法與否?

There is legal uncertainty as to whether selective foeticide is authorised under section 47A of the Offences Against the Person Ordinance (1967). Medical and legal issues surrounding a case of selective foeticide in a triplet pregnancy are reported.published_or_final_versio

Cost-minimizing preemptive scheduling of mapreduce workloads on hybrid clouds

MapReduce has become the dominant programming model for processing massive amounts of data on cloud platforms. More and more enterprises are now utilizing hybrid clouds, consisting of private infrastructure owned by themselves and public clouds such as Amazon EC2, to process their spiky MapReduce workloads, which fully utilize their own on-premise resources while outsourcing the tasks only when needed. With disparate workloads of different MapReduce tasks, an efficient scheduling mechanism is in need to enable efficient utilization of the on-premise resources and to minimize the task outsourcing cost, while meeting the task completion time requirements as well. In this paper, a fine-grained model is described to characterize the scheduling of heterogeneous MapReduce workloads, and an online algorithm is proposed for joint task admission control into the private cloud, task outsourcing to the public cloud, and VM allocation to execute the admitted tasks on the private cloud, such that the time-averaged task outsourcing cost is minimized over the long run. The online algorithm features preemptive scheduling of the tasks, where a task executed partially on the on-premise infrastructure can be paused and scheduled to run later. It also achieves desirable properties such as meeting a pre-set task admission ratio and bounding the worst-case task completion time, as proven by our rigorous theoretical analysis. © 2013 IEEE.published_or_final_versio

The role of c-Myc in phagocytosis of mycobacteria in human macrophages

Poster Presentation (Doctor’s Session)This journal issue contain proceedings of the CongressMycobacterium tuberculosis is an intracellular pathogen and the causative agent of the disease tuberculosis. Macrophages are the major immunocytes to initiate host immunity against mycobacteria. Among the multiple strategies employ by macrophages to defence against mycobacteria, phagocytosis is the first step. Throughphagocytosis, macrophages could not only clear the pathogens from infection sites, but also present antigens derived from the engulfed bacteria to lymphoid cells. c-Myc is a transcription factor that regulates a variety of target genes. It can form a complex with Max and bind to the enhancer box sequences of the promoter to mediate the transcription. Recently, our group revealed that c-Myc has a potential role in regulating the antimicrobial responses in macrophages. Here, we further revealed that c-Myc may play a positive role in phagocytosis and contribute to host defense to mycobacteria. Pretreatment of c-Myc inhibitor, 10058-F4, could significantly reduce the amount of mycobacteria internalised by macrophages. The acidification of phagolysosome in mycobacteria infected macrophages was also inhibited by 10058-F4. Further investigation showed that macrophages phagocytose mycobacteria in a PI3K/Akt independent pathway. And the action of c-Myc inhibitor does not affect the expression levels of Rho family GTPases. However, we found that 10058-F4 could significantly inhibit phorsphorylation of ERK1/2 kinase, which has been indicated to play a role in FcR mediated phagocytosis in macrophage. In conclusion, c-Myc may play a role in phagocytosis of mycobacteria through regulating phorsphorylation of ERK1/2.published_or_final_versio

The role of oncogene in mycobacteria-induced antophagy in human macrophages

Poster PresentationMacrophages are the major immunocytes to initiate both innate and adaptive immune responses against Mycobacterium tuberculosis (Mtb), a causative agent of tuberculosis. Upon mycoabcteria infection, macrophages could eliminate the intracellular bacteria through different cell death pathways, including apoptosis and autophagy. c-Myc is a transcription factor that regulates a variety of target genes and control different cellular functions such as proliferation and immune resposnse. Recently, our group revealed that c-Myc has a potential role in regulating the antimicrobial responses in macrophages. Here we use BCG, a live attenuated strain of Mycobacterium bovis, which is similar to Mtb in antigenic composition, as a model to study the role of c-Myc in regulating mycobacteria-induced autophagy. We first investigated the role of c-Myc in BCG-induced LC3BII levels. Knocking down c-Myc by siRNA could decrease BCG-induced LC3BII levels. We found that BCG-induced autophagy is dependent on JNK and p38 and independent on PI3K or ERK pathways. And knocking down of c-Myc could significantly inhibit phosphorylation of p38. In conclusion, c-Myc may play a positive role in mycobacteria-induced autophagy in human macrophages.published_or_final_versio

Persistence of hepatic hepatitis B virus after serological clearance of HBsAG with autologous peripheral stem cell transplantation

Delayed clearance of hepatitis B surface antigen was previously reported in a 38 year old woman after high dose chemotherapy with autologous peripheral blood stem cell rescue. Sixteen months later, this patient remained hepatitis B surface antigen negative, hepatitis B surface anti-body positive, and serum hepatitis B DNA negative by polymerase chain reaction. Serial liver biopsies (one at hepatitis B e antigen positive stage, one at hepatitis B e antibody positive stage, and one at hepatitis B surface antigen negative and hepatitis B surface antibody positive stage) showed a gradual resolution of the inflammatory activity with loss of hepatitis B e antigen and then hepatitis B surface antigen in the serum. However, the degree of fibrosis, though mild, remained the same. With the serological clearance of hepatitis B surface antigen, a small amount of hepatitis B virus DNA was still detectable in the nuclei of liver cells.published_or_final_versio

Early changes of auditory brain stem evoked response after radiotherapy for nasopharyngeal carcinoma - A prospective study

A prospective study of the effect of radiotherapy for nasopharyngeal carcinoma on hearing was carried out on 49 patients who had pure tone, impedance audiometry and auditory brain stem evoked response (ABR) recordings before, immediately, three, six and 12 months after radiotherapy. Fourteen patients complained of intermittent tinnitus after radiotherapy. We found that 11 initially normal ears of nine patients developed a middle ear effusion, three to six months after radiotherapy. There was mixed sensorineural and conductive hearing impairment after radiotherapy. Persistent impairment of ABR was detected immediately after completion of radiotherapy. The waves I-III and I-V interpeak latency intervals were significantly prolonged one year after radiotherapy. The study shows that radiotherapy for nasopharyngeal carcinoma impairs hearing by acting on the middle ear, the cochlea and the brain stem auditory pathway.published_or_final_versio

Rapid aneuploidy testing (knowing less) versus traditional karyotyping (knowing more) for advanced maternal age: What would be missed, who should decide?

Objectives The application of rapid aneuploidy testing as a stand-alone approach in prenatal diagnosis is much debated. The major criticism of this targeted approach is that it will not detect other chromosomal abnormalities that will be picked up by traditional karyotyping. This study aimed to study the nature of such chromosomal abnormalities and whether parents would choose to terminate affected pregnancies. Design Retrospective study on a cytogenetic database. Setting Eight public hospitals in Hong Kong. Participants The karyotype results of 19 517 amniotic fluid cultures performed for advanced maternal age (≥35 years) from 1997 to 2002 were classified according to whether they were detectable by rapid aneuploidy testing. The outcomes of pregnancies with abnormal karyotypes were reviewed from patient records. Results In all, 333 (1.7%) amniotic fluid cultures yielded abnormal karyotypes; 175 (52.6%) of these were detected by rapid aneuploidy testing, and included trisomy 21 (n=94, 28.2%), trisomy 18 or 13 (n=21, 6.3%), and sex chromosome abnormalities (n=60, 18.0%). The other 158 (47.4%) chromosomal abnormalities were not detectable by rapid aneuploidy testing, of which 63 (18.9%) were regarded to be of potential clinical significance and 95 (28.5%) of no clinical significance. Pregnancy outcomes in 327/333 (98.2%) of these patients were retrieved. In total, 143 (42.9%) of these pregnancies were terminated: 93/94 (98.9%) for trisomy 21, 20/21 (95.2%) for trisomy 18 or 13, 19/60 (31.7%) for sex chromosome abnormalities, and 11/63 (17.5%) for other chromosomal abnormalities with potential clinical significance. There were no terminations in the 95 pregnancies in which karyotyping results were regarded to be of no clinical significance. Conclusions 'Knowing less' by the rapid aneuploidy stand-alone testing could miss about half of all chromosomal abnormalities detectable by amniocentesis performed for advanced maternal age. Findings from two fifths of the latter were of potential clinical significance, and the parents chose to terminate one out of six of the corresponding pregnancies. If both techniques are available, parents could have enhanced autonomy to choose.published_or_final_versio

Surveillance of acute flaccid paralysis in Hong Kong: 1997 to 2002

Objectives. To describe the characteristics of patients reported with acute flaccid paralysis between 1997 and 2002, and to evaluate the performance of the acute flaccid paralysis surveillance system using indicators recommended by the World Health Organization. Design. Retrospective study. Setting. Department of Health, Hong Kong. Participants. Children aged younger than 15 years who were reported to the Department of Health between 1997 and 2002 with acute flaccid paralysis. Results. Of 120 children with acute flaccid paralysis reported between 1997 and 2002, 42% were younger than 5 years of age. None of the cases were acute poliomyelitis or polio-compatible. A neurological cause was identified in 67.5% of cases, of which the most common was Guillain-Barré syndrome (42%), followed by transverse myelitis (15%). All except one of the performance indicators consistently met World Health Organization requirements and thus demonstrated the effectiveness of the acute flaccid paralysis surveillance programme. The acute flaccid paralysis notification rate consistently exceeded 1.0 per 100 000 population below 15 years of age. The requirement for adequate stool investigation was the single indicator that did not satisfy World Health Organization requirements. This highlighted the importance of maintaining physicians' awareness of acute flaccid paralysis surveillance. Conclusion. Hong Kong should remain vigilant for acute flaccid paralysis. The effective surveillance system and its evaluation may serve as a model for surveillance of other infectious diseases.published_or_final_versio

Surface treatments of indium-tin-oxide substrates: Comprehensive investigation of mechanical, chemical, thermal, and plasma treatments

Various surface treatments significantly affect the work function and surface roughness of indium tin oxide (ITO), and thusly influence charge injection and overall performance of organic light emitting diodes (OLEDs). Large number of treatments, most commonly oxygen plasma treatment and UV-ozone treatment, have been proposed to improve characteristics of ITO. In this work, we have investigated a) mechanical treatments (mechanical rubbing, followed by ultrasonic bath), b) chemical treatments (dipping into aqueous solutions of various acids, including acids which have not been investigated previously) c) thermal treatments (thermal annealing in different atmospheres) d) plasma treatments e) UV ozone treatment f) different combinations of the above. We have measured surface sheet resistance of the samples and investigated surface morphology of the treated samples and compared them to "as-received" samples. We have selected several treatments giving best results. Then we have fabricated OLEDs using ITO substrates treated with treatments selected, as well as a control OLED fabricated on "as-received" ITO. The impact of ITO treatments on the performance of OLEDs have been investigated on two types of devices, OLEDs with and without transport layer, having the structures glass/ITO/Alq 3/Al and glass/ITOFrPD/Alq 3/Al, respectively, where Alq 3 (tris-(8-hydroxyquinoline) aluminum) is emitting layer and TPD (N,N′-diphenyl-N,N′-bis(3-methyl-phenyl)-1, 1′ biphenil-4,4′diamine) is a hole transport layer.published_or_final_versio

Efficient attenuation of Friedreich's ataxia (FRDA) cardiomyopathy by modulation of iron homeostasis-human induced pluripotent stem cell (hiPSC) as a drug screening platform for FRDA

Friedreich’s ataxia (FRDA), a recessive neurodegenerative disorder commonly associated with hypertrophic cardiomyopathy, is caused by silencing of the frataxin (FXN) gene encoding the mitochondrial protein involved in iron-sulfur cluster biosynthesis. We aimed to utilize our previously established FRDA human induced pluripotent stem cell (hiPSC) derived cardiomyocytes model as a platform to assess the efficacy of treatment with either the antioxidant coenzyme Q10 analog, idebenone (IDE) or the iron chelator, deferiprone (DFP), which are both under clinical trial. In fact, DFP was able to more significantly suppress synthesis of reactive oxygen species (ROS) than IDE at the dosages of 10 nM and 25 μM respectively which agreed with the reduced rate of intracellular accumulation of iron by DFP treatment from 25 to 50 µM. With regard to cardiac electrical-contraction (EC) coupling function, decay velocity of calcium handling kinetics in FRDA-hiPSC-cardiomyocytes was significantly improved by DFP treatment but not by IDE. Further mechanistic studies revealed DFP also modulated iron induced mitochondrial stress as reflected by mitochondria network disorganization and decline in level of respiratory chain protein. In addition, iron-response protein (IRP-1) regulatory loop was overridden by DFP as reflected by the attenuated transferrin receptor (TSFR) suppression thereby reducing further iron uptake.published_or_final_versio