Twenty-eight-day mortality among patients with severe or critical COVID-19 in Hong Kong during the early stages of the pandemic.

INTRODUCTION: In 2020, patients with critical coronavirus disease 2019 (COVID-19) had a 28-day mortality rate of 30% to 50% worldwide; outcomes among such patients in Hong Kong were unknown. This study investigated 28-day mortality and corresponding risk factors among patients with severe or critical COVID-19 in Hong Kong. METHODS: This retrospective cohort study included adult patients with severe or critical COVID-19 who were admitted to three public hospitals in Hong Kong from 22 January to 30 September 2020. Demographics, comorbidities, symptoms, treatment, and outcomes were examined. RESULTS: Among 125 patients with severe or critical COVID-19, 15 (12.0%) died within 28 days. Overall, the median patient age was 64 years; 48.0% and 54.4% of patients had hypertension and obesity, respectively. Respiratory samples were confirmed severe acute respiratory syndrome coronavirus 2 RNA-positive after a median of 3 days. The most common presenting symptom was fever (80.0% of patients); 45.6% and 32.8% of patients received care in intensive care unit and required mechanical ventilation, respectively. In logistic regression analysis comparing 28-day survivors and non-survivors, factors associated with greater 28-day mortality were older age (odds ratio [OR] per 1-year increase in age=1.12, 95% confidence interval [CI]=1.04-1.21; P=0.002), history of stroke (OR=15.96, 95% CI=1.65-154.66; P=0.017), use of renal replacement therapy (OR=15.32, 95% CI=2.67-87.83; P=0.002), and shorter duration of lopinavir-ritonavir treatment (OR per 1-day increase=0.82, 95% CI=0.68-0.98; P=0.034). CONCLUSION: The 28-day mortality rate among patients with severe or critical COVID-19 in Hong Kong was 12.0%. Older age, history of stroke, use of renal replacement therapy, and shorter duration of lopinavir-ritonavir treatment were independent predictors of 28-day mortality.

Hong Kong experiences the 'Ultimate superbug': NDM-1 Enterobacteriaceae.

We report the second imported case of New Delhi metallo-beta-lactamase (NDM-1) Enterobacteriaceae encountered in Hong Kong soon after the patient's arrival in the territory for medical care. As NDM-1 is spreading throughout the world via international travel, being an international city, Hong Kong was always expected to encounter the same public health threat. This case also illustrates the importance of active surveillance of at-risk patients in preventing the spread of this 'superbug'.

Evaluation of in-house and commercial genotyping assays for molecular typing of hepatitis C virus in Hong Kong.

This study aims to evaluate genotyping assays for hepatitis C virus (HCV). An in-house nucleic acid sequencing method is performed in parallel with the Roche Linear Array HCV genotyping test on 73 HCV-positive (66 clinical samples and seven proficiency testing quality control samples) and 12 HCV-negative samples (11 clinical samples and one proficiency testing sample). The performance of the in-house method was comparable with that of the Roche assay (concordance rate: 89.4%). Discordant results included four mixed infections missed by the in-house method, two false-negatives with the Roche assay, and three discrepant results. The in-house method exhibited a higher resolution (subtype vs. genotype level) at a lower running cost (25% of the commercial assay). The in-house method was also used to genotype 375 HCV clinical isolates to determine the genotypic distribution of HCV in Hong Kong between 2005 and 2008. A total of 441 (52.8%) clinical isolates proved to be genotype 1, which shows a poorer response to interferon therapy. Genotype 6 was the next most common (32.0%). Prevalence of genotypes 2 and 3 was 7.7% and 6.6%, respectively, and prevalence of genotypes 4 and 5 was 0.9% and 0%, respectively. Although the in-house nucleic acid sequencing method failed to detect a few cases of mixed HCV infection, its high resolution and low running cost make it suitable for surveillance and outbreak investigation.

Nonlinear cross-phase modulation with intense single-cycle terahertz pulses.

We have demonstrated nonlinear cross-phase modulation in electro-optic crystals using intense, single-cycle terahertz (THz) radiation. Individual THz pulses, generated by coherent transition radiation emitted by subpicosecond electron bunches, have peak energies of up to 100 microJ per pulse. The time-dependent electric field of the intense THz pulses induces cross-phase modulation in electro-optic crystals through the Pockels effect, leading to spectral shifting, broadening, and modulation of copropagating laser pulses. The observed THz-induced cross-phase modulation agrees well with a time-dependent phase-shift model.

Speechless after bone marrow transplantation: a rare complication of parainfluenza virus related group in an adult.

Upper respiratory tract (URT) viral infections may cause severe consequences during myeloablative bone marrow transplantation (BMT). We present a patient with parainfluenza virus (PIV) infection during the course of BMT. He remained relatively asymptomatic during the course of cytopenia, but presented with complete loss of voice and severe laryngitis a few days after engraftment, which is not usual for adult PIV infections. Seroconversion to PIV and marked increase in antibody titres was demonstrated, with complete lymphoid engraftment. Our case illustrated that the virulence of some URT viral infections depend on host immune factors, and may remain latent until graft versus host responses can be mounted.

A case of thoracic empyema due to suppurative melioidosis.

Melioidosis is considered a rare disease in Hong Kong, and its diagnosis and treatment can be difficult. We report the case of a patient who presented with thoracic empyema. The material sampled from the empyema was initially labelled Burkholderia cepacia. The diagnosis of melioidosis due to Burkholderia pseudomallei could only be made after repeated cultures, and performing arginine dihydrolase and serological tests. The patient was initially treated with imipenem for 2 weeks, and then with ciprofloxacin as maintenance therapy. A resistant strain of the organism developed after 7 months of treatment. The patient was then given co-amoxiclav. Repeated courses of surgical drainage and debridement were also instituted. Subsequent computed tomographic scanning of the thorax showed gradual resolution of the empyema.

Human papillomavirus type 16 E6 induces cervical cancer cell migration through the p53/microRNA-23b/urokinase-type plasminogen activator pathway.

Deregulation of microRNA (miRNA or miR) expression in human cervical cancer is associated frequently with human papillomavirus (HPV) integration. miR-23b is often downregulated in HPV-associated cervical cancer. Interestingly, urokinase-type plasminogen activator (uPA), the miR-23b target, is detected in cervical cancer, but not in normal cervical tissues. Thus, the importance of miR-23b and uPA in HPV-associated cervical cancer development is investigated. In this study, the high-risk subtype HPV-16 E6 oncoprotein was found to decrease the expression of miR-23b, increase the expression of uPA, and thus induce the migration of human cervical carcinoma SiHa and CaSki cells. uPA is the target gene for miR-23b as the miR repressed uPA expression and interacted with the 3'-untranslated region of uPA mRNA. The tumor suppressor p53 is known to be inactivated by HPV-16 E6. A consensus p53 binding site is detected in the promoter region of miR-23b, whereas p53 trans-activated and also interacted with the miR's promoter. Therefore, p53 is believed to mediate the HPV-16 E6 downregulation of miR-23b. From the above, miR-23b/uPA are confirmed to be involved in HPV-16 E6-associated cervical cancer development.

Surface-plasmon-enhanced third-harmonic generation in thin silver films.

Optical third-harmonic generation (THG) is dipole allowed. I report a 10(3) signal enhancement of THG that is due to the excitation of a surface plasmon in thin silver films by an attenuated-total-internal-ref lection geometry. Because the THG signal depends on the cube of the incident intensity and the second-harmonic generation depends on the square of the intensity, the THG overtakes the second-harmonic generation at laser intensities beyond 6 x 10(11) W/cm(2).