Reciprocal transplant experiment reveals multiple factors influencing changes in coral microbial communities across climate zones

Previous studies have demonstrated the influence of external factors (environmental factors and the coral host factors) on the community structure of coral-associated bacteria. However, the internal factors, e.g. the interaction within the bacterial community or bacteria itself, have often been overlooked in studies of the coral microbiome. Hence, we performed a reciprocal transplant of corals between two different climate zones to examine the resultant alterations in coral-associated bacterial communities. The findings highlight the significance of environmental factors, host selection, and highly resilient bacteria in shaping the coral microbial composition. The results support that coral species consistently harbor specific predominant bacterial groups influenced by host selection, while locations display unique bacterial taxa due to environmental variations. The transplantation of corals into new environments leads to a gradual shift in the bacterial community, from initially resembling that of the native location to eventually resembling that of the transplanted location, emphasizing the crucial role of bacterial community composition for coral survival under changing ambient conditions. Furthermore, highly resilient bacteria that persisted throughout the reciprocal transplant experiment demonstrated their adaptability to environmental and host changes, suggesting the presence of robust adaptation or resistance mechanisms in bacterial communities. Genetic adaptations within the prevalent bacterial group, Endozoicomonas, were also observed, suggesting variations in resilience and adaptation capabilities among different phylotypes. This study highlights the need to conduct further investigations into the coral-associated bacteria themselves, as they may hold some key insights into understanding the dynamics of coral-associated microbial communities. These data also highlight some key species of coral-associated bacteria which could benefit coral in response to alterations in ambient environment.

Stability of enteroviruses on toys commonly found in kindergarten

Hand, foot, and mouth disease (HFMD) is a contagious childhood disease caused by enteroviruses including enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6) and CV-A16 transmitted via direct and indirect contact. Different types of toy surfaces can affect the stability of viruses. Understanding the stability of enteroviruses on toys provides insightful data for effective disinfection in kindergartens or homes. Porous (ethylene-vinyl acetate mat foam, paper, pinewood, polyester fabric, and squishy polyurethane foam) and non-porous (acrylonitrile butadiene styrene plastic and stainless-steel coin) surfaces were inoculated with EV-A71 at 4, 24, and 35°C, and coxsackieviruses at 24°C. Infectious enteroviruses were recovered and titred in median tissue culture infectious dose assay (TCID50). Atomic force microscopy (AFM) images were taken from surfaces to examine association of surface roughness with virus stability. Overall, infectious enteroviruses were persistent on all non-porous and porous surfaces. Virus persistence was longest at 4°C followed by 24°C and 35°C. EV-A71 half-lives ranged between 6.4-12.8 hours at 4°C, 2.4-6.7 hours at 24°C, and 0.13-2.7 hours at 35°C. At lower virus titres exposed to 24°C, half-lives of enteroviruses ranged from 0.1-1.4 hours. Surface roughness values from AFM suggested smooth surfaces of non-porous surfaces were associated with better virus stability. Temperature, enterovirus concentration, and type of surface affected persistence and stability of enteroviruses. Our findings suggest both porous and non-porous surfaces in kindergartens allow enterovirus persistence and should be frequently disinfected to curb HFMD outbreaks in kindergartens.

Similar but different: Characterization of dddD gene-mediated DMSP metabolism among coral-associated Endozoicomonas

Endozoicomonas are often predominant bacteria and prominently important in coral health. Their role in dimethylsulfoniopropionate (DMSP) degradation has been a subject of discussion for over a decade. A previous study found that Endozoicomonas degraded DMSP through the dddD pathway. This process releases dimethyl sulfide, which is vital for corals coping with thermal stress. However, little is known about the related gene regulation and metabolic abilities of DMSP metabolism in Endozoicomonadaceae. In this study, we isolated a novel Endozoicomonas DMSP degrader and observed a distinct DMSP metabolic trend in two phylogenetically close dddD-harboring Endozoicomonas species, confirmed genetically by comparative transcriptomic profiling and visualization of the change of DMSP stable isotopes in bacterial cells using nanoscale secondary ion spectrometry. Furthermore, we found that DMSP cleavage enzymes are ubiquitous in coral Endozoicomonas with a preference for having DddD lyase. We speculate that harboring DMSP degrading genes enables Endozoicomonas to successfully colonize various coral species across the globe.

Seasonal Patterns of Picocyanobacterial Community Structure in the Kuroshio Current

The nutrient-scarce, warm, and high-salinity Kuroshio current has a profound impact on both the marine ecology of the northwestern Pacific Ocean and the global climate. This study aims to reveal the seasonal dynamics of picoplankton in the subtropical Kuroshio current. Our results showed that one of the picocyanobacteria, Synechococcus, mainly distributed in the surface water layer regardless of seasonal changes, and the cell abundance ranged from 104 to 105 cells mL-1. In contrast, the maximum concentration of the other picocyanobacteria, Prochlorococcus, was maintained at more than 105 cells mL-1 throughout the year. In the summer and the autumn, Prochlorococcus were mainly concentrated at the water layer near the bottom of the euphotic zone. They were evenly distributed in the euphotic zone in the spring and winter. The stirring effect caused by the monsoon determined their distribution in the water column. In addition, the results of 16S rRNA gene diversity analysis showed that the seasonal changes in the relative abundance of Synechococcus and Prochlorococcus in the surface water of each station accounted for 20 to 40% of the total reads. The clade II of Synechococcus and the High-light II of Prochlorococcus were the dominant strains in the waters all year round. Regarding other picoplankton, Proteobacteria and Actinobacteria occupied 45% and 10% of the total picoplankton in the four seasons. These data should be helpful for elucidating the impacts of global climate changes on marine ecology and biogeochemical cycles in the Western Boundary Currents in the future.

Amoeba Genome Reveals Dominant Host Contribution to Plastid Endosymbiosis

Eukaryotic photosynthetic organelles, plastids, are the powerhouses of many aquatic and terrestrial ecosystems. The canonical plastid in algae and plants originated >1 Ga and therefore offers limited insights into the initial stages of organelle evolution. To address this issue, we focus here on the photosynthetic amoeba Paulinella micropora strain KR01 (hereafter, KR01) that underwent a more recent (∼124 Ma) primary endosymbiosis, resulting in a photosynthetic organelle termed the chromatophore. Analysis of genomic and transcriptomic data resulted in a high-quality draft assembly of size 707 Mb and 32,361 predicted gene models. A total of 291 chromatophore-targeted proteins were predicted in silico, 208 of which comprise the ancestral organelle proteome in photosynthetic Paulinella species with functions, among others, in nucleotide metabolism and oxidative stress response. Gene coexpression analysis identified networks containing known high light stress response genes as well as a variety of genes of unknown function (“dark” genes). We characterized diurnally rhythmic genes in this species and found that over 49% are dark. It was recently hypothesized that large double-stranded DNA viruses may have driven gene transfer to the nucleus in Paulinella and facilitated endosymbiosis. Our analyses do not support this idea, but rather suggest that these viruses in the KR01 and closely related P. micropora MYN1 genomes resulted from a more recent invasion.

Detection of enteroviruses during a 2018 hand, foot and mouth disease outbreak in Malaysia

Hand, foot, and mouth disease (HFMD) is a common childhood disease caused by enteroviruses. In 2018, a HFMD outbreak in Malaysia affected over 76,000 children. In this study, we used RT-qPCR and CODEHOP PCR to detect the causative agents in 89 clinically diagnosed HFMD patients in Kuala Lumpur and Selangor. Most (62.9%) of the children were below 3 years old. PCR with either assay detected enteroviruses in 84.2% (75/89) and CODEHOP PCR successfully typed 66.7% (50/75) of the enteroviruses. Sequencing of CODEHOP amplicons showed co-circulation of multiple enteroviruses with coxsackievirus A6 (CV-A6) and A16 as the predominant serotypes, but not the neurovirulent enterovirus A71. CV-A6 infection was more common in children less than 12 months old (p=0.01) and was more likely to cause vesicles in the gluteal area (p=0.01) compared to other enteroviruses. Establishing a robust identification method during HFMD outbreaks is important for patient management and public health responses.

Spatiotemporal Changes in the Bacterial Community of the Meromictic Lake Uchum, Siberia

Lake Uchum is a newly defined meromictic lake in Siberia with clear seasonal changes in its mixolimnion. This study characterized the temporal dynamics and vertical profile of bacterial communities in oxic and anoxic zones of the lake across all four seasons: October (autumn), March (winter), May (spring), and August (summer). Bacterial richness and diversity in the anoxic zone varied widely between time points. Proteobacteria was the dominant bacterial phylum throughout the oxic and anoxic zones across all four seasons. Alphaproteobacteria (Loktanella) and Gammaproteobacteria (Aliidiomarina) exhibited the highest abundance in the oxic and anoxic zone, respectively. Furthermore, there was a successional shift in sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria in the anoxic zone across the seasons. The most dominant SRB, Desulfonatronovibrio sp., is likely one of the main producers of hydrogen sulfide (H₂S) and typically accumulates the most H₂S in winter. The representative anoxygenic phototrophic bacterial group in Lake Uchum was purple sulfur bacteria (PSB). PSB were dominant (60.76%) in summer, but only had 0.2-1.5% relative abundance from autumn to spring. Multivariate analysis revealed that the abundance of these SRB and PSB correlated to the concentration of H₂S in Lake Uchum. Taken together, this study provides insights into the relationships between changes in bacterial community and environmental features in Lake Uchum.

Comparative genomics: Dominant coral-bacterium Endozoicomonas acroporae metabolizes dimethylsulfoniopropionate (DMSP)

Dominant coral-associated Endozoicomonas bacteria species are hypothesized to play a role in the coral sulfur cycle by metabolizing dimethylsulfoniopropionate (DMSP) into dimethylsulfide (DMS); however, no sequenced genome to date harbors genes for this process. In this study, we assembled high-quality (>95% complete) draft genomes of strains of the recently added species Endozoicomonas acroporae (Acr-14T, Acr-1, and Acr-5) isolated from the coral Acropora sp. and performed a comparative genomic analysis on the genus Endozoicomonas. We identified DMSP CoA-transferase/lyase-a dddD gene homolog in all sequenced genomes of E. acroporae strains-and functionally characterized bacteria capable of metabolizing DMSP into DMS via the DddD cleavage pathway using RT-qPCR and gas chromatography (GC). Furthermore, we demonstrated that E. acroporae strains can use DMSP as a carbon source and have genes arranged in an operon-like manner to link DMSP metabolism to the central carbon cycle. This study confirms the role of Endozoicomonas in the coral sulfur cycle.

Abiotic and Biotic Factors Affecting the Ingestion Rates of Mixotrophic Nanoflagellates (Haptophyta)

Mixotrophic haptophytes comprise one of several important groups of mixotrophic nanoflagellates in the pelagic environment. This study aimed to investigate if phagotrophy in mixotrophic haptophytes is regulated by light or other factors in the surface (SE) and bottom (BE) of the euphotic zone in the subtropical northwestern Pacific Ocean. We estimated the rates of bacterial ingestion by haptophytes using fluorescently labeled bacteria (FLBs) and fluorescence in situ hybridization. Haptophyte diversity and abundance were also investigated in the same sampling area. The annual mean abundance of haptophytes was 419 ± 85.6 cells mL^-1 in both SE and BE. Cells 3-5 μm in size were the dominant group in all haptophytes and accounted for majority of bacteria standing stock removed by haptophytes (53%). Most haptophyte ingestion rates (IRs) were not significantly different between the two layers (average SE ingestion rate: 12.5 ± 2.29 bac Hap^-1 h^-1; BE: 14.7 ± 3.03 bac Hap^-1 h^-1). Furthermore, the haptophyte IRs were negatively correlated with nitrate concentrations in the SE and positively correlated with bacterial abundances in the BE, which accounts for the significantly high IRs in August 2012 and 2013. These findings imply that mixotrophic haptophytes in this region had different factors affecting phagotrophy to adapt to the ambient light intensity alterations between SE and BE.

Causative agents of hand, foot and mouth disease in University Malaya Medical Centre, Kuala Lumpur, Malaysia in 2012-2013

Hand, foot and mouth disease (HFMD) is a childhood illness, commonly caused by enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16). In recent years, unusual HFMD outbreaks caused by coxsackievirus A6 (CV-A6) have been reported. From May 2012 to September 2013, enteroviruses were detected in 25 HFMD patients in University Malaya Medical Centre, Kuala Lumpur, Malaysia. The predominant serotypes were EV-A71 (48%) and CV-A6 (48%), followed by CV-A16 (4%). CV-A6 patients (mean age, 2.1) were significantly younger than EV-A71 patients (mean age, 3.3). There were no significant differences observed in clinical features between EV-A71 and CV-A6 patients. Since enteroviruses are difficult to differentiate clinically, the conserved 5' untranslated region (5' UTR) was used to identify enterovirus serotypes. Phylogenetic analysis of 5' UTR showed distinct clustering of viruses as EV-A71, CV-A16 and CV-A6. Further genotyping with capsid genes showed that all the EVA71 sequences belonged to subgenotype B5, while the CV-A16 sequence belonged to subgenotype B2b. CV-A6 sequences were clustered into genotypes D1 and D2, with recent isolates from Seri Kembangan, Malaysia and China. In summary, 59.5% of HFMD cases in our centre in 2012-2013 were caused by EV-A71, CV-A16 and the newly emerging CV-A6. This study also demonstrated that 5' UTR is suitable for preliminary identification of enteroviruses during HFMD outbreaks, but specific capsid genes such as VP1 and VP4/VP2 are required for further genotyping. Apart from measures to control the spread of the virus during an outbreak of HFMD, identification of EV-A71 as the etiological agent is important as EV-A71 is a major cause of severe neurological complications and potentially fatal.

Diagnosis of human enterovirus A71 infection in Malaysia using a commercial IgM-capture enzyme-linked immunosorbent assay and an IgM-colloidal gold immunochromatographic assay

Hand, foot and mouth disease (HFMD) is a common childhood infection caused by many enteroviruses, including enterovirus A71 (EV-A71). As EV-A71 is associated with severe neurological disease, early diagnosis is critical for clinical and public health management. In developing countries such as Malaysia, laboratory capacity to carry out EV-A71 IgM detection is greater than that of the gold standard methods of virus culture or molecular detection. This study evaluated two diagnostic kits, EV-A71 IgM-capture enzyme-linked immunosorbent (ELISA) and EV-A71 IgM-colloidal gold immunochromatographic assay (GICA), which had previously only been assessed in China. The assays were tested with 89 serum samples from patients with suspected HFMD. The sensitivity, specificity, positive predictive value, and negative predictive value rates were 78.4%, 80.8%, 74.4%, and 84.0%, respectively, for the IgM-capture ELISA, and 75.7%, 76.9%, 70.0%, and 81.6% for the IgM GICA. These performance measures were similar between the two assays. Concordance between the two assays was 91.1%. The sensitivity rates were lower than those previously reported, likely because the multiple circulating EV-A71 genotypes in Malaysia differ from the C4 subgenotype found in China and used in the assays. Both assays had low false positive rates (12.5% and 16.7% for ELISA and GICA, respectively) when tested on sera from patients confirmed to have enteroviruses. Both diagnostic kits are suitable for early diagnosis of HFMD caused by EVA71 in Malaysia, but confirmation with culture or PCR is still important.

Zika virus and its potential re-emergence in Malaysia

Zika virus (ZIKV) has re-emerged to cause explosive epidemics in the Pacific and Latin America, and appears to be associated with severe neurological complications including microcephaly in babies. ZIKV is transmitted to humans by Aedes mosquitoes, principally Ae. aegypti, and there is historical evidence of ZIKV circulation in Southeast Asia. It is therefore clear that Malaysia is at risk of similar outbreaks. Local and international guidelines are available for surveillance, diagnostics, and management of exposed and infected individuals. ZIKV is the latest arbovirus to have spread globally beyond its initial restricted niche, and is unlikely to be the last. Innovative new methods for surveillance and control of vectors are needed to target mosquito-borne diseases as a whole.

Phylogenetic analysis of human metapneumovirus among children with acute respiratory infections in Kuala Lumpur, Malaysia

Human metapneumovirus (HMPV) is a recently discovered cause of viral respiratory infections. We describe clinical and molecular epidemiology of HMPV cases diagnosed in children with respiratory infection at University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The prevalence rate of HMPV between 2010 and 2012 was 1.1%, and HMPV contributed 6.5% of confirmed viral respiratory infections. The HMPV patients had a median age of 1.6 years, and a median hospital admission of 4 days. The most common clinical presentations were fever, rhinitis, pneumonia, vomiting/diarrhoea, and bronchiolitis. Based on the partial sequences of F fusion gene from 26 HMPV strains, 14 (54%) were subgenotype A2b, which was predominant in 2010; 11 (42%) were subgenotype B1, which was predominant in 2012; and 1 (4%) was subgenotype A2a. Knowledge of the circulating subgenotypes in Malaysia, and the displacement of predominant subgenotypes within 3 years, is useful data for future vaccine planning.

Chikungunya infection in Malaysia: comparison with dengue infection in adults and predictors of persistent arthralgia

BACKGROUND

Chikungunya virus (CHIKV) and dengue virus (DENV) co-circulate in areas endemic with the Aedes mosquito vectors. Both viruses cause similar illnesses which may be difficult to distinguish clinically. CHIKV is also associated with persistent arthralgia.

OBJECTIVES

To compare and describe factors which differentiate between DENV and CHIKV infections on presentation; and to describe predictors of persistent arthralgia in CHIKV patients.

STUDY DESIGN

Patients aged >14 years diagnosed with acute CHIKV and DENV infections in Kuala Lumpur, Malaysia were retrospectively identified. Clinical and laboratory data were obtained from medical records, and compared. CHIKV patients were telephoned 15-24 months later and interviewed about persistent symptoms. Logistic regression analysis was performed.

RESULTS

A total of 53 CHIKV and 113 DENV patients were included. CHIKV patients were older and more likely to be female. CHIKV was independently associated with arthralgia and rash, while DENV was associated with myalgia, raised aspartate transaminase, and leucopaenia. Forty CHIKV patients were followed up, with a median duration of self-reported arthralgia of 3 months (range, 0-24 months). Eighteen (45%) had persistent arthralgia beyond 4 months, for which age >40 years was an independent predictor. At 1 year, 9 (22.5%) patients had arthralgia.

CONCLUSION

In Kuala Lumpur, selected clinical and laboratory predictors help to distinguish between DENV and CHIKV infections. Persistent arthralgia was a frequent sequel of CHIKV infection in this cohort.

Comparative genetic analysis of VP4, VP1 and 3D gene regions of enterovirus 71 and coxsackievirus A16 circulating in Malaysia between 1997-2008

Three genomic regions, VP4 capsid, VP1 capsid and 3D RNA polymerase of human enterovirus 71 (EV-71) and coxsackievirus A16 (CV-A16) were sequenced to understand the evolution of these viruses in Malaysia. A total of 42 EV-71 and 36 CV-A16 isolates from 1997- 2008 were sequenced. Despite the presence of many EV-71 subgenotypes worldwide, only subgenotypes B3, B4, B5, C1 and C2 were present in Malaysia. Importation of other subgenotypes such as C3, C4/D and C5 from other countries was infrequent. For CV-A16, the earlier subgenotype B1 was replaced by subgenotypes B2a and the recent B2c. Subgenotype B2a was present throughout the study while B2c only emerged in 2005. No genetic signatures could be attributed to viral virulence suggesting that host factors have a major role in determining the outcome of infection. Only three EV-71 B3 isolates showed non-consistent phylogeny in the 3D RNA polymerase region which indicated occurrence of recombination in EV-71. High genetic diversity was observed in the Malaysian EV-71 but Malaysian CV-A16 showed low genetic diversity in the three genomic regions sequenced. EV-71 showed strong purifying selection, but that occurred to a lesser extent in CV-A16.

On Keelungia pulex nov. gen. et nov. sp., a heterotrophic euglenoid flagellate that lacks pellicular plates (Euglenophyceae, Euglenida)

Keelungia pulex nov. gen. et nov. sp. is described from coastal waters of NE Taiwan. The new species is heterotrophic and feeds on bacteria. Cells are oblong-ovoid, biflagellate and glide along the sides of the flask. Each cell is approximately 8-11μm long, and one of the smallest euglenoid flagellates presently known. Keelungia lacks pellicular plates and in this respect resembles diplonemids and Symbiontida, which are thought to be among the basal groups of Euglenozoa. SEM showed the presence of 10 evenly spaced longitudinal striae in the cell surface, but the striae are difficult to see in the light microscope. TEM showed each stria to comprise a double set of very low longitudinal ridges separated by a shallow furrow, and supported by ca 5 microtubules beneath the plasmalemma, unlike the situation in diplonemids and Symbiontida. The cell surface was further subtended by an extensive system of rough cisternae of endoplasmic reticulum. Keelungia pulex is phylogenetically related to species of Ploeotia and to Lentomonas applanata, but differs in details of the feeding apparatus and in the absence of pellicular plates. Sequencing of SSU rDNA indicates that Ploeotia, Keelungia and Entosiphon form a clade near the base of the euglenoid phylogenetic tree.

The genetic basis of divergent pigment patterns in juvenile threespine sticklebacks

Animal pigment patterns are important for a range of functions, including camouflage and communication. Repeating pigment patterns, such as stripes, bars and spots have been of particular interest to developmental and theoretical biologists, but the genetic basis of natural variation in such patterns is largely unexplored. In this study, we identify a difference in a periodic pigment pattern among juvenile threespine sticklebacks (Gasterosteus aculeatus) from different environments. Freshwater sticklebacks exhibit prominent vertical bars that visually break up the body shape, but sticklebacks from marine populations do not. We hypothesize that these distinct pigment patterns are tuned to provide crypsis in different habitats. This phenotypic difference is widespread and appears in most of the freshwater populations that we sampled. We used quantitative trait locus (QTL) mapping in freshwater-marine F2 hybrids to elucidate the genetic architecture underlying divergence in this pigmentation pattern. We identified two QTL that were significantly associated with variation in barring. Interestingly, these QTL were associated with two distinct aspects of the pigment pattern: melanophore number and overall pigment level. We compared the QTL locations with positions of known pigment candidate genes in the stickleback genome. We also identified two major QTL for juvenile body size, providing new insights into the genetic basis of juvenile growth rates in natural populations. In summary, although there is a growing literature describing simple genetic bases for adaptive coloration differences, this study emphasizes that pigment patterns can also possess a more complex genetic architecture.

Chikungunya virus-associated death in Malaysia

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus which causes fever, rash, and arthralgia. In the past, life-threatening complications were very rarely reported. However, during the recent worldwide outbreaks, there have been several reports of unusually severe complications and deaths. Malaysia is experiencing a nationwide outbreak of CHIKV, with over 10 000 patients affected since April 2008. We report the first case of culture-confirmed CHIKV-associated death in Malaysia, in a patient with fever, rash, acute exacerbation of pre-existing heart failure, rhabdomyolysis, and multiple organ failure. CHIKV infections may cause atypical, severe or fatal presentations.

Determination of Lycopene in Dietary Supplements and Raw Materials by High-Performance Liquid Chromatography: Collaborative Study

A collaborative study was conducted to evaluate the interlaboratory performance of an LC method for lycopene in dietary supplements and the raw materials commonly used in their manufacture. Twelve laboratories from six countries agreed to participate in the study. Results from 10 laboratories were received and are reported. Five dietary supplements, including both tablets and a softgel capsule with a lycopene content ranging from 25 g to 25 mg per unit, and three raw materials, including gelatin-based beadlets, vegetarian beadlets, and a suspension in oil ranging from 5 to 20 lycopene, were analyzed as blind duplicates. In addition to the commercial products, two positive controls and a negative control were included in the study. For the raw materials studied, the repeatability relative standard deviations (RSDr) ranged from 1.49 to 5.13 for total lycopene, and the reproducibility relative standard deviations (RSDR) ranged from 3.84 to 9.21 with HorRat values from 1.23 to 3.24. For finished products, the RSDr ranged from 1.31 to 4.62, RSDR from 4.28 to 10.5, and HorRat values from 0.79 to 2.07. Corresponding values for all-trans-lycopene were significantly higher. It is recommended that the method be considered for Official First Action for all-trans- and total lycopene in finished products and raw materials.

Pigmented nanoflagellates grazing on Synechococcus: seasonal variations and effect of flagellate size in the coastal ecosystem of subtropical Western Pacific

We investigated seasonal variation of grazing impact of the pigmented nanoflagellates (PNF) with different sizes upon Synechococcus in the subtropical western Pacific coastal waters using grazing experiments with fluorescently labeled Synechococcus (FLS). For total PNF, conspicuous seasonal variations of ingestion rates on Synechococcus were found, and a functional response was observed. To further investigate the impact of different size groups, we separated the PNF into four categories (<3, 3-5, 5-10, and >10 microm). Our results indicated that the smallest PNF (<3 microm PNF) did not ingest FLS and was considered autotrophic. PNF of 3-5 microm in size made up most of the PNF community; however, their ingestion on Synechococcus was too low (0.1-1.9 Syn PNF(-1) h(-1)) to support their growth, and they had to depend on other prey or photosynthesis to survive. The ingestion rate of the 3-5 microm group exhibited no significant seasonal variation; by contrast, the ingestion rates of 5-10 and >10 microm PNFs showed significant seasonal variation. During the warm season, 3-5 microm PNF were responsible for the grazing of 12% of Synechococcus production, 5-10 microm PNF for 48%, and >10 microm PNF for 2%. Taken together, our results demonstrate that the PNF of 3-10 microm consumed most Synechococcus during the warm season and exhibited a significant functional response to the increase in prey concentration.

Varicella-zoster virus seroprevalence in healthcare workers in Kuala Lumpur, Malaysia

Varicella-zoster virus (VZV) infections are a particular problem in healthcare settings. A survey of chickenpox was carried out amongst healthcare workers (HCWs) following potential ward exposures. A prior history of chickenpox was given by 61/98 (62.2%). Of 64 HCWs tested for VZV IgG, 10 (15.6%) were seronegative, indicating susceptibility. The sensitivity, specificity, positive predictive value, and negative predictive value of a history of prior chickenpox were 57.4%, 90%, 96.4%, and 31.0%, respectively. VZV screening of HCWs without a history of chickenpox, and vaccination of susceptible HCWs should be undertaken in this hospital.

A Novel Carbon Nanotube Structure Formed in Ultra-Long Nanochannels of Anodic Aluminum Oxide Templates

We report the fabrication of a novel carbon structure consisting of uniform carbon nanotubes formed in the nanochannels of anodic aluminum oxide (AAO) templates, with the surface side open and connected by a uniform carbon sheet. The uniformity of the fabricated CNT arrays, plus the carbon film on the AAO surface interconnecting the open ends of all CNTs, constitute the major characteristics unique to our carbon structures. Some potential applications of such structures are noted.

Transcatheter embolisation of visceral pseudoaneurysms--technical difficulties and modification of embolisation technique

We report 13 successful emergency embolisations for 12 pseudoaneurysms performed in 10 patients. For five pseudoaneurysms the embolisation technique was modified according to number of supplying vessels, flow rate of pseudoaneurysms, vascular anatomy and whether there was clinical evidence of re-bleeding or not. Apart from traditional embolisation technique, modified embolisation techniques are also useful for endovascular therapy of pseudoaneurysms.

Virucidal activity of Virkon S on human enterovirus

The efficacy of Virkon S, a commercial disinfectant as a virucidal spray against human enterovirus 71 (HEV71), the causative agent of the fatal form of hand, foot and mouth disease was examined. At least one log10 reduction of HEV71 titer was achieved when one spray of Virkon (1% or 2%) with ten minutes of contact time was applied. The infectivity was completely lost when four sprays of 1% or 2% Virkon were applied, suggesting that at least four sprays of 1% Virkon to the surface bound HEV71 was necessary to completely inactivate the virus. These findings suggest that Virkon S at the proper concentration is suitable to be used as an effective and easy to use disinfectant against HEV71.

Predictive value of the user seal check in determining half-face respirator fit

Guidelines issued by the Centers for Disease Control and Prevention and the World Health Organization state that healthcare workers should wear N95 masks or higher-level protection during all contact with suspected cases of severe acute respiratory syndrome. Before use, the manufacturer recommends performing a user seal check to ensure that the mask is fitted correctly. This study aimed to test the ability of the user seal check to detect poorly fitting masks. This study is a retrospective review of a mask-fitting programme carried out in the intensive care unit of the Prince of Wales Hospital in Hong Kong. In this programme, all staff were tested with two types of N95 mask and one type of N100 mask. The results of the documented user seal check were then compared with the formal fit-test results from a PortaCount. Using a PortaCount reading of 100 as the criterion for a correctly fitted mask, the user seal check wrongly indicated that the mask fitted on 18–31% of occasions, and wrongly indicated that it did not fit on 21–40% of occasions. These data indicate that the user seal check should not be used as a surrogate fit test. Its usefulness as a pre-use test must also be questioned.

Massive myocardial calcification in second-trimester fetuses: antenatal detection and causes

Massive myocardial calcifications were detected by antenatal ultrasound examination in four second-trimester fetuses. In one fetus, multiple cardiac rhabdomyomas were the initial diagnosis. One fetus presented with arthrogryposis and the brain and spinal cord showed severe hypoxic-ischemic damage. One fetus was hydropic and had severe cardiac malformations. The fourth fetus had congenital heart block and maternal serum was positive for anti-Ro and anti-La antibodies. Myocardial calcifications in the first three fetuses were most likely to be caused by hypoxic-ischemic damage to the heart, and immunological mechanisms were responsible in the other fetus. Antenatally detected myocardial echogenic foci in a fetus leading to a termination of pregnancy or associated with fetal death should be investigated with a full postmortem examination. It is important to confirm the presence of calcifications as distinct from a rhabdomyoma as genetic counseling is completely different. The demonstration of associated lesions in other organs also helps to explain the pathogenesis underlying this condition.

Subcutaneous primitive neuroectodermal tumour in the abdominal wall of a child: long-term survival after local excision

Tumours of the peripheral primitive neuroectodermal tumour/Ewing's sarcoma (PNET/ES) family can rarely occur as primary lesions within the skin and subcutis. We present a case of subcutaneous PNET within the abdominal wall of a 33-month-old child. Histologically it was a small round cell tumour that marked strongly for CD99 and displayed ultrastructual evidence of neural differentiation. The tumour was completely excised, but due to an initial misdiagnosis no adjuvant therapy was given. Despite this, the patient is well without evidence of disease 10 years and 3 months after surgery. A review of similar cases reveals not all patients are as fortunate, suggesting combination therapy, including chemotherapy, is still the best treatment for these tumours, even when small and superficial. Our report therefore highlights the importance of recognising PNET/ES in the skin and subcutis so appropriate therapy can be administered.

Subcutaneous primitive neuroectodermal tumour in the abdominal wall of a child: long-term survival after local excision

Tumours of the peripheral primitive neuroectodermal tumour/Ewing's sarcoma (PNET/ES) family can rarely occur as primary lesions within the skin and subcutis. We present a case of subcutaneous PNET within the abdominal wall of a 33-month-old child. Histologically it was a small round cell tumour that marked strongly for CD99 and displayed ultrastructual evidence of neural differentiation. The tumour was completely excised, but due to an initial misdiagnosis no adjuvant therapy was given. Despite this, the patient is well without evidence of disease 10 years and 3 months after surgery. A review of similar cases reveals not all patients are as fortunate, suggesting combination therapy, including chemotherapy, is still the best treatment for these tumours, even when small and superficial. Our report therefore highlights the importance of recognising PNET/ES in the skin and subcutis so appropriate therapy can be administered.

Chinese attitudes to institutional care of their aged. A study of members from the Chung Wah Association, Western Australia

OBJECTIVE

To examine Chinese attitudes to institutional care of their aged and to identify the factors that influence these attitudes.

METHOD

A cross sectional survey of 815 randomly selected members of the Chung Wah Association, Western Australia was undertaken in 1997 using a mailed self administered questionnaire. The survey instrument was developed through a literature review, interviews and pilot testings and consisted of categorical and noncategorical items. The data were analysed using the SAS (V 6.12) software package. Factor analysis, logistic regression and Chi-square analysis were used on the data. The statistical significance level was set at p < or = 0.05.

RESULTS

A total of 431 (53%) completed responses were received. The study showed that 86% of the respondents agreed that the disabled elderly should be institutionalised. Age contributed mainly to the respondents' attitudes to institutionalising the disabled elderly, while the respondents' sex, education, occupation, country of origin and length of residence in Australia did not. Social responsibilities together with the health factors of the elderly had important effects on these attitudes. About 55% of respondents agreed that their Chinese culture influenced their attitude. Only 21% of the respondents agreed that the nondisabled elderly should be institutionalised, 54% disagreed, while 24% remained neutral. Respondents who were likely to institutionalise their disabled elderly were also unlikely to live with their children when they became disabled. A majority of respondents were in favour of government funding of institutions and care givers of the elderly.

CONCLUSION

The study provided several important observations and information for health planners and general practitioners to identify the aged at risk of institutionalisation and make arrangements for community support for effected families so that the aged can be encouraged to remain with their families.

Pulmonary sequestration presenting as a prenatally detected suprarenal lesion in a neonate

An echogenic suprarenal mass was detected antenatally in the fetus by routine ultrasound scan. Resection of the mass after delivery confirmed an extralobar pulmonary sequestration with features of a type II congenital cystic adenomatoid malformation of the lung. The lesion should be considered in all neonates presenting with a suprarenal or upper abdominal mass particularly when the mass has been detected antenatally. Ultrasound-guided needle biopsy if feasible could provide a reasonably confident diagnosis. Congenital anomalies in other organs should be looked for carefully.

Temporary hearing impairment after general anesthesia--a case report

The incidence of hearing impairment after anesthesia is rare. We report a case who received left total knee and hip replacement and developed severe hearing impairment of the left ear after general anesthesia. Examination of the left ear by an otolaryngologist showed that there was no noticeable abnormality. The hearing acuity recovered gradually and returned to normal 3 days later. The use of nitrous oxide during anesthesia was incriminated as the possible cause.

Pleuropulmonary blastoma: four cases

Pleuropulmonary blastoma (PPB) is a rare malignant neoplasm affecting children. A retrospective review was carried out of patients diagnosed as having PPB at one institute over a period of 16 years. The presentation, diagnosis, treatment, and family history were studied. PPB usually presents with symptoms and signs of respiratory tract infection, and the diagnosis may be delayed. There are no distinguishing clinical features or imaging studies. The diagnosis is made on histologic examination of tumour material and is sometimes difficult to differentiate from benign cystic lung lesions. The treatment is primarily complete excision of the tumour, followed in some cases by intense chemotherapy. PPB is a strong predictor of the presence of tumours in close relatives. Four patients treated at our institute are discussed along with a review of the literature.

Childhood cancer in New Zealand 1990 to 1993

An epidemiological study of childhood cancer in New Zealand identified 409 children aged 0 to 14 years with malignant neoplasms newly diagnosed between 1990 and 1993 inclusive. The original microscopic material on which the diagnoses were based was reviewed in 398 cases and the neoplasms were allocated into the 12 major groupings and 48 further subcategories of the International Classification of Childhood Cancer (ICCC). The pathology reviewers agreed with group and subcategory classification of the confirmed cancers in all but one case of acute leukemia and three cancers of the central nervous system. Changes were also made in the FAB classification of three cases of acute non-lymphocytic leukemia and in the further subcategorisation of three Hodgkin's lymphomas and ten astrocytomas. The results show a high level of diagnostic accuracy for confirmed childhood neoplasms in that time period. Nine of 15 cases of malignant melanoma notified to the study were not confirmed for various reasons, which included a change in the pathological diagnosis in four cases. Compared with Victoria (Australia), New Zealand has a high incidence rate of lymphomas in boys and an unusual female preponderance of Wilms' tumor cases.

Low dose ketamine and midazolam as supplements for spinal anesthesia

BACKGROUND

Low dose ketamine and midazolam together were used as supplements during spinal anesthesia to provide analgesia for insertion of spinal needle and intraoperative sedation.

METHODS

Two regimens of drug combination (ketamine 0.5 mg/kg and midazolam 0.05 mg/kg in group I, n = 30; ketamine 0.5 mg/kg and midazolam 0.1 mg/kg in group II, n = 30) were administered intravenously before proceeding lumbar puncture.

RESULTS

Systolic and diastolic arterial blood pressure, heart rate, and arterial oxygen saturation did not change significantly before and after the administration of drugs. Most patients in both groups showed good analgesic response to the lumbar puncture. The medications induced a brief unconsciousness (4.1 min in group I; 8.5 min in group II). The time from drug administration to recovery of mental orientation was 8.8 min in group I and 15.1 min in group II. The regimens also provided intraoperative sedation. Patients in group II appeared to be more depressed than group I in the first 30 min. None of the patients had significant respiratory disturbance, involuntary movement, or recall to spinal puncture. There were 7 patients in group I and 4 patients in group II who experienced dreaming.

CONCLUSIONS

The use of low dose ketamine together with midazolam as supplement for spinal anesthesia is helpful in anesthetic practice.

Juvenile granulosa cell tumor of the testis: report of two cases in newborns

Two juvenile granulosa cell tumors in the testes of two newborns are described. The lesion, though rare, should be considered whenever a cystic testicular mass is encountered in newborns or young infants. Orchidectomy is the only treatment required because local recurrence or metastases have never been observed. Karyotyping of the patient is essential when the external genitalia are abnormal.

Utilisation of Australian health care services by ethnic Chinese

Australia is a multicultural society in which migrants from non-English-speaking backgrounds may be more vulnerable to illness after their new settlement, and language difficulties and cultural differences may affect their use of health services. The present qualitative study used focus group interviews to explore the health services used by Chinese migrants from Hong Kong and China. The general findings included strong preference for Chinese-speaking general practitioners, insufficient interpreter services, low use of preventive services, and lack of knowledge about the existence and role of ethnic health workers. The paper reports specific differences between migrants from China and Hong Kong, and by age group. It discusses reasons for these findings and notes the implications.

Assessment of invasive growth pattern and lymphocytic infiltration in colorectal cancer

A total of 122 specimens of colorectal cancer were re-assessed in relation to the reporting of invasive growth pattern (expanding vs. infiltrating) and presence or absence of peritumoral lymphocytic infiltrate as used in the Jass prognostic classification. Jass agreed with 69% of cases reported as infiltrating and 90% of reported as expanding. This parameter was distributed similarly amongst Dukes B and C cases in the original assessment (P = 0.27), whereas in the reviewed data infiltrating cases were more likely to be staged as Dukes C (P = 0.04). Jass agreed with 44% of lymphocyte present and 94% of lymphocyte absent assessments. The original lymphocyte assessments showed no significant differences in distribution between Dukes A and B cases (P = 0.12) or B and C cases (P = 0.75), whereas the reviewed data showed significant differences for A vs. B (P = 0.015) and B vs. C cases (P = 0.0025). Criteria for assessment were circulated to eight observers who revisited 20 of the cases in which there was disagreement. Consensus agreement with Jass was achieved in nine of 10 cases for invasive growth pattern and seven of 10 cases for lymphocyte infiltration (with two being evenly split). Most observers showed at least fair levels of agreement with Jass and some achieved excellent levels of agreement. This study indicates that assessment of criteria used in the Jass prognostic system for colorectal cancer is less than optimal in routine practice, but is improved through the provision of simple guidelines.

Misoprostol is as effective as gemeprost in termination of second trimester pregnancy when combined with mifepristone: a randomised comparative trial

A prospective randomized study was conducted to compare the efficacy of misoprostol with gemeprost when combined with mifepristone for termination of second trimester pregnancy. Patients requesting termination of second trimester pregnancy were randomized into two groups. In both groups of patients, 200 mg of mifepristone was given 36 to 48 hours before the administration of prostaglandins. In Group 1, the women were given 400 micrograms of oral misoprostol every 3 hours up to 5 doses. In Group 2, patients were given 1 mg of vaginal gemeprost every 6 hours up to 4 doses. The main outcomes measured were the induction-abortion intervals (the interval between the first dose of prostaglandin and abortion) and the incidence of side effects. Altogether, 50 subjects were recruited with 25 women in each group. The mean age and parity of the women and the mean gestational age of the two groups of women were comparable. There was no significant difference in the median induction-abortion intervals (8.7 hours in Group 1 and 10.8 hours in Group 2) or the incidence of side effects between the two groups of patients. We conclude that misoprostol is as effective as gemeprost in termination of second trimester pregnancy when combined with mifepristone.

Ovarian Sertoli-Leydig cell tumor with retiform pattern

Sertoli-Leydig cell tumors (SLCT) are sex cord-stromal tumors which exhibit testicular differentiation.1 They account for less than 0.2% of ovarian neoplasms in total but comprise 4% of ovarian tumors in females under 20 yrs of age.2 The morphological appearance of these tumors varies more widely than that of any other ovarian tumor except for the teratomas. Histologically they are now classified into 5 categories: well-differentiated, intermediately differentiated, poorly differentiated, heterologous and retiform.1 We describe the case of an ovarian Sertoli-Leydig cell tumor with retiform pattern in a 7 yr old girl.

[Arytenoid subluxation following endotracheal intubation--a case report]

A previously healthy 39-yr-old man was scheduled for exploratory laparotomy due to acute abdomen. There was no sign of difficult intubation. After induction of anesthesia with thiopental and succinylcholine, the trachea was easily intubated with a 7.0 mm cuffed endotracheal tube. Surgery for a ruptured appendix with 2 drainage tubes lasted for 75 min was uneventful. At the end of surgery, the endotracheal tube was removed without difficulty. On the 1st postoperative day, the patient developed stridor. The symptom persisted even after conservative treatment and removal of NG tube. On the 12th postoperative day, a telescopic videolarygoscopy revealed immobile right vocal cord with anterior and medial displacement to the right. Arytenoid cartilage was moderately edematous. A diagnosis of right arytenoid subluxation was then made. On the 17th postoperative day, a closed reduction of right arytenoid cartilage using direct laryngoscope was performed successively under general anesthesia. Eight weeks after the reduction, his voice and laryngoscopic findings were normal. There has been only 18 reports with 27 cases of this complication found in the literature. However, it is generally believed that it is not so unusual. The post-intubation syndromes, such as sore throat, dysphonia, odynophagia, difficulty in swallowing or breathing which persists beyond 5 days warrant ENT consultation. Abnormal mobility of vocal cord, edema over arytenoid area found by indirect laryngoscopy should suggest the complication. Further confirmation is then needed. Although the result of our case is good, the reduction should ideally be done within 24-48 h after the incidence to avoid unfavorable long-term sequelae.

The value of a single sensitive urine pregnancy test in prediction of pregnancy outcome

A simple and reliable indicator for pregnancy outcome will be valuable clinically for patient management and for counselling women whose pregnancies are results of subfertility treatment. This study aimed at evaluating the ICON II test, a simple semiquantitative sensitive urine pregnancy test, in predicting pregnancy outcome in women who conceived after various forms of subfertility treatment. The ICON II test was performed on day 20 after the ovulating dose of hCG administration or spontaneous LH surge. One hundred and forty-five consecutive pregnancies were studied, 99 being viable and 46 nonviable which included subclinical abortion, clinical abortion and ectopic pregnancies. There was a significant difference in the luteal serum progesterone and hCG levels between viable and nonviable pregnancies. There was also a significant difference in the ICON II test result, i.e. either weakly positive (hCG of 25-50 IU/l) and positive (hCG > 50 IU/l) and the pregnancy outcome (p < 0.0001). The specificity of a weakly positive ICON II test in predicting poor pregnancy outcome was 98.8% whereas the sensitivity was 28.6%. In conclusion, a weakly positive ICON II test is useful in predicting poor pregnancy outcome.