Dynamics of childhood obesity in Hong Kong throughout the COVID-19 pandemic before and after the school closures: a 3-year longitudinal study.

OBJECTIVE: This study is to evaluate if there is any difference in the balance between incidence of and remission from overweight/obesity in Hong Kong school-age children before and during the COVID-19 pandemic over three years. METHODS: This is a retrospective longitudinal study that involved children aged 6-16 years from a database of the School Physical Fitness Award Scheme. RESULTS: 2765 students were longitudinally followed up for two years. The prevalence of childhood overweight/obesity was increased between the 2019 and 2021 academic years (P < 0.001). During the COVID-19 pandemic, the rate of obesity remission significantly reduced by 7.9 % (P = 0.003), at a background of a plateau of obesity among children and adolescents. CONCLUSIONS: Our study provides evidence on the impact of school closure and home confinement as a standard infection control measure for the prevention of COVID-19, which are likely to break the balance between incidence of and remission from childhood obesity.

Ten-year refractive and visual outcomes of intraocular lens implantation in infants with congenital cataract.

INTRODUCTION: There is no consensus regarding optimal target refraction after intraocular lens implantation in infants. This study aimed to clarify relationships of initial postoperative refraction with long-term refractive and visual outcomes. METHODS: This retrospective review included 14 infants (22 eyes) who underwent unilateral or bilateral cataract extraction and primary intraocular lens implantation before the age of 1 year. All infants had ≥10 years of follow-up. RESULTS: All eyes exhibited myopic shift over a mean follow-up period of 15.9 ± 2.8 years. The greatest myopic shift occurred in the first postoperative year (mean=-5.39 ± +3.50 dioptres [D]), but smaller amounts continued beyond the tenth year (mean=-2.64 ± +2.02 D between 10 years postoperatively and last follow-up). Total myopic shift at 10 years ranged from -21.88 to -3.75 D (mean=-11.62 ± +5.14 D). Younger age at operation was correlated with larger myopic shifts at 1 year (P=0.025) and 10 years (P=0.006) postoperatively. Immediate postoperative refraction was a predictor of spherical equivalent refraction at 1 year (P=0.015) but not at 10 years (P=0.116). Immediate postoperative refraction was negatively correlated with final best-corrected visual acuity (BCVA) (P=0.018). Immediate postoperative refraction of ≥+7.00 D was correlated with worse final BCVA (P=0.029). CONCLUSION: Considerable variation in myopic shift hinders the prediction of long-term refractive outcomes in individual patients. When selecting target refraction in infants, low to moderate hyperopia (<+7.00 D) should be considered to balance the avoidance of high myopia in adulthood with the risk of worse long-term visual acuity related to high postoperative hyperopia.

Mesoscopic Energy Minimization Drives Pseudomonas aeruginosa Biofilm Morphologies and Consequent Stratification of Antibiotic Activity Based on Cell Metabolism.

Segregation of bacteria based on their metabolic activities in biofilms plays an important role in the development of antibiotic resistance. Mushroom-shaped biofilm structures, which are reported for many bacteria, exhibit topographically varying levels of multiple drug resistance from the cap of the mushroom to its stalk. Understanding the dynamics behind the formation of such structures can aid in design of drug delivery systems, antibiotics, or physical systems for removal of biofilms. We explored the development of metabolically heterogeneous Pseudomonas aeruginosa biofilms using numerical models and laboratory knockout experiments on wild-type and chemotaxis-deficient mutants. We show that chemotactic processes dominate the transformation of slender and hemispherical structures into mushroom structures with a signature cap. Cellular Potts model simulation and experimental data provide evidence that accelerated movement of bacteria along the periphery of the biofilm, due to nutrient cues, results in the formation of mushroom structures and bacterial segregation. Multidrug resistance of bacteria is one of the most threatening dangers to public health. Understanding the mechanisms of the development of mushroom-shaped biofilms helps to identify the multidrug-resistant regions. We decoded the dynamics of the structural evolution of bacterial biofilms and the physics behind the formation of biofilm structures as well as the biological triggers that produce them. Combining in vitro gene knockout experiments with in silico models showed that chemotactic motility is one of the main driving forces for the formation of stalks and caps. Our results provide physicists and biologists with a new perspective on biofilm removal and eradication strategies.

Epidemiology of myopia and prevention of myopia progression in children in East Asia: a review.

INTRODUCTION: Myopia (short-sightedness) exhibits high prevalence in East Asia. Methods to mitigate myopia progression are important in preventing the vision-threatening complications associated with high myopia. In this review, we examine the regional epidemiology of myopia and provide updated evidence regarding interventions to slow myopia progression in children. METHODS: We performed a literature search using PubMed from the date of inception through 25 June 2018. Studies involving myopia epidemiology and control of myopia progression were selected; only studies published in English were reviewed. Preference was given to prospective studies, as well as those conducted in Hong Kong or East Asia. RESULTS: Atropine eye drops and pirenzepine eye gel are highly effective for controlling myopia progression in children. Orthokeratology, peripheral defocus contact lenses, bifocal or progressive addition spectacles, and increased involvement in outdoor activities are also effective for controlling myopia progression; however, myopia undercorrection and single vision contact lenses are ineffective. CONCLUSION: Although various methods are effective for controlling myopia progression in children, no curative remedy exists for myopia. Health care professionals should be aware of the available methods, as well as their risks and benefits. Treatment should be individualised and based on the preferences of the patient's family, after full discussion of the risks and benefits of each modality.

Botulinum toxin as an initial therapy for management of sixth nerve palsies caused by nasopharyngeal carcinomas.

PurposeThe purpose of this study is to evaluate the efficacy and safety of botulinum toxin injection as a primary treatment for strabismus in a cohort of patients with nasopharyngeal carcinoma (NPC)-related chronic sixth nerve palsy.Patients and methodsWe retrospectively reviewed all cases of NPC-related sixth nerve palsy receiving botulinum toxin injection in the Hong Kong Eye Hospital between January 2009 and January 2016. Only cases with diplopia for at least 6 months; and failed a trial of Fresnel prism therapy were recruited. We excluded cases with prior strabismus surgery and multiple cranial nerve palsies. Patients were offered botulinum toxin injection as primary treatment for their strabismus and were given further injections or offered surgery if diplopia persisted. Success with botulinum toxin was defined as a final distant orthophoria of <15 PD in primary gaze, no diplopia in primary position, and no head turn, as measured 6 months after the last injection, without requiring a second treatment.ResultsA total of 25 patients were included in the study. All patients received concurrent chemo-radiotherapy for NPC. There was a statistically significant reduction in the mean deviation at distant after the last injection compared to that at presentation (P<0.001, Wilcoxin signed rank test). Overall, 7 patients (28%) achieved clinical success and 15 patients (64%) remained diplopia-free by repeated botulinum toxin injections alone. Nine patients went on to receive definitive surgery and all achieved good ocular alignment after surgery. Transient ptosis or vertical deviation was seen in 7 patients, which resolved within 3 months and no serious complications arose from the treatment in our series.ConclusionsBotulinum toxin injection is a relatively less-invasive alternative to surgery that can be done under a topical anesthesia setting, which improves patient's quality of life via reduction in diplopia. It is a recommendable initial option in patients with chronic nerve palsies who may have higher risks associated with strabismus surgery.

The role of endotoxin in protection of adult rats from oxygen-induced lung toxicity.

Adult rats show evidence of severe lung damage after 72h of continuous exposure to hyperoxia (96-98% O2). Treatment of adult rats with a solution of Plasmanate, inadvertently contaminated with endotoxin-producing organisms, or with purified endotoxin itself markedly altered the lung toxicity associated with hyperoxic exposure (survival in treated animals = 110/113 [97%] versus survival in untreated animals = 56/172 [33%]). After 72h of hyperoxic exposure, the endotoxin-treated rats demonstrated significant increases in lung superoxide dismutase, catalase, and glutathione peroxidase activity, a protectant enzyme response not seen in untreated adult rats. The basis for endotoxin's protective effect from hyperoxic lung damage is believed to be related to the stimulated increase in activity of the pulmonary antioxidant enzyme defense system. Some previously known actions of endotoxin are speculated to also serve a protective function by opposing some of the usual detrimental effects of high concentrations of O2 on the lung.

Minimal access approach to the management of large ovarian cysts.

Laparoscopy has become an accepted method of management for ovarian cysts. Large ovarian cysts, however, have traditionally been, and continue to be treated by laparotomy. This is mainly due to technical difficulties and the possibility of malignancy. We describe four patients in whom laparoscopy was used to remove large ovarian cysts. Laparoscopic guided aspiration was performed, followed by extra-abdominal excision of the cyst. This approach has the advantages of minimising the risk of spillage of cyst fluid, a smaller incision compared to laparotomy, as well as faster recovery. We advocate this method for large unilocular benign cysts.

Ocular toxicity of hydroxychloroquine.

OBJECTIVES: To review the types, incidence, pathogenesis, risk factors, and clinical characteristics of hydroxychloroquine ocular toxicity and current views about its screening and management. DATA SOURCES: Literature search of Medline up to May 2005. STUDY SELECTION: Key words for the literature search were 'hydroxychloroquine', 'chloroquine', 'ocular', 'toxicity', 'retinopathy', and 'screening'. DATA EXTRACTION: Original articles and review papers were examined. DATA SYNTHESIS: Hydroxychloroquine ocular toxicity includes keratopathy, ciliary body involvement, lens opacities, and retinopathy. Retinopathy is the major concern: others are more common but benign. The incidence of true hydroxychloroquine retinopathy is exceedingly low; less than 50 cases have been reported. Although its pathogenesis is unclear, risk factors include: daily dosage of hydroxychloroquine, cumulative dosage, duration of treatment, coexisting renal or liver disease, patient age, and concomitant retinal disease. Patients usually complain of difficulty in reading, decreased vision, missing central vision, glare, blurred vision, light flashes, and metamorphopsia. They can also be asymptomatic. Most patients have a bull's eye fundoscopic appearance. All patients have field defects including paracentral, pericentral, central, and peripheral field loss. Colour vision is usually undisturbed in early retinopathy, but is impaired in the advanced stage. Most patients have visual loss. Some patients with advanced retinopathy may experience deteriorating visual acuity even after cessation of treatment. There is no consensus on the definition of retinopathy, most-effective ophthalmological assessment, or frequency of screening. Regular screening may be necessary to detect reversible premaculopathy. Cessation of the drug is the only effective management of the toxicity. CONCLUSION: Consensus with regard to various important aspects of hydroxychloroquine ocular toxicity is limited, especially the definition of true hydroxychloroquine retinopathy, the most effective ophthalmological assessment, and frequency of screening. Decisions to stop medication must be made in conjunction with the rheumatologist or physician managing the patient. Management of hydroxychloroquine retinopathy remains a clinical challenge.

Advances of optical coherence tomography in myopia and pathologic myopia.

The natural course of high-axial myopia is variable and the development of pathologic myopia is not fully understood. Advancements in optical coherence tomography (OCT) technology have revealed peculiar intraocular structures in highly myopic eyes and unprecedented pathologies that cause visual impairment. New OCT findings include posterior precortical vitreous pocket and precursor stages of posterior vitreous detachment; peripapillary intrachoroidal cavitation; morphological patterns of scleral inner curvature and dome-shaped macula. Swept source OCT is capable of imaging deeper layers in the posterior pole for investigation of optic nerve pits, stretched and thinned lamina cribrosa, elongated dural attachment at posterior scleral canal, and enlargement of retrobulbar subarachnoid spaces. This has therefore enabled further evaluation of various visual field defects in high myopia and the pathogenesis of glaucomatous optic neuropathy. OCT has many potential clinical uses in managing visual impairing conditions in pathologic myopia. Understanding how retinal nerve fibers are redistributed in axial elongation will allow the development of auto-segmentation software for diagnosis and monitoring progression of glaucoma. OCT is indispensable in the diagnosis of various conditions associated with myopic traction maculopathy and monitoring of post-surgical outcomes. In addition, OCT is commonly used in the multimodal imaging assessment of myopic choroidal neovascularization. Biometry and topography of the retinal layers and choroid will soon be validated for the classification of myopic maculopathy for utilization in epidemiological studies as well as clinical trials.

Suppression of the tumorigenicity of mutant p53-transformed rat embryo fibroblasts through expression of a newly cloned rat nonmuscle myosin heavy chain-B.

In our previous study, a rat homolog of human nonmuscle myosin heavy chain-B (nmMHC-B) was identified by mRNA differential display comparing of transformed against nontransformed Rat 6 cells overexpressing mutant p53val135 gene. The nmMHC-B was found to be expressed in normal Rat 6 embryo fibroblast cell line, but markedly suppressed in the mutant p53val135-transformed Rat 6 cells. To examine the possible involvement of nmMHC-B in cell transformation, we first cloned and sequenced the full length cDNA of rat nmMHC-B, which was then cloned into an ecdysone-expression vector. The resulting construct was introduced into the T2 cell line, a mutant p53val135-transformed Rat 6 cells lacking the expression of the endogenous nmMHC-B. The clonal transfectants, expressing muristerone A-induced nmMHC-B, displayed a slightly flatter morphology and reached to a lower saturation density compared to the parental transformed cells. Reconstitution of actin filamental bundles was also clearly seen in cells overexpressing the nmMHC-B. In soft agar assays, nmMHC-B transfectants formed fewer and substantially smaller colonies than the parental cells in response to muristerone A induction. Moreover, it was strikingly effective in suppressing the tumorigenicity of the T2 cells when tested in nude mice. Thus, the nmMHC-B, known as a component of the cytoskeletal network, may act as a tumor suppressor gene. Our current finding may reveal a novel role of nmMHC-B in regulating cell growth and cell signaling in nonmuscle cells. Oncogene (2001) 20, 58 - 68.

Incorporating the ABI GeneScan analysis to a RACE-based technique for mapping multiple transcription initiation sites.

Determination of transcription initiation sites has commonly been performed by primer extension and RNase protection assay using radioactively labeled oligonucleotides. Recently, a protocol based on modified 5' rapid amplification of cDNA ends (RACE) with the use of fluorescently labeled primer was developed. Here, we describe the use of RACE-based technique in conjunction with the GeneScan analysis for the determination of transcription initiation sites of genes of interest. The RACE technique is based on the ligation of an adapter to both ends of the cDNAs. The gene of interest was first amplified by PCR using a gene-specific and a 5' adapter primer. Subsequently, nested PCR was performed using an internal gene-specific primer paired with a fluorescently end-labeled adapter primer. The size of the fluorescently labeled PCR products was directly determined by the ABI PRISM 377 GeneScan Analyzer. This novel approach provides an accurate, sensitive, and convenient method for mapping transcription initiation sites, especially for genes with multiple transcription initiation sites, for genes expressed at low levels, and for splice variants that display alternative splicing farther than a few hundred nucleotides downstream from the transcription initiation site. This article describes the application of this new method in the mapping of transcription initiation sites of two splice variants of rat frizzled related protein transcripts.

Intrapartum fetal pulse oximetry. Part I: Principles and technical issues.

UNLABELLED: Fetal pulse oximetry has been advocated as a means of improving the specificity of cardioto-cography in intrapartum fetal surveillance. The objective of this article, the first of two reviewing the current literature on fetal pulse oximetry, is to discuss the principles of this new and evolving technology, its development, and the various factors that can affect its readings during fetal monitoring. It serves as a prelude to the second article, which profiles the clinical application of fetal pulse oximetry. Literature pertaining to this topic was selected from a MEDLINE search from 1965 through September 1999, with additional sources obtained through cross-referencing. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to explain the principles of fetal pulse oximetry, and describe the factors that affect the calibration of fetal pulse oximeters and the factors that affect the fetal pulse oximeter readings.

Intrapartum fetal pulse oximetry. Part 2: Clinical application.

UNLABELLED: Part II continues by discussing the clinical application of fetal pulse oximetry in intrapartum fetal surveillance as reviewed in the literature. It profiles the predictive ability of fetal pulse oximetry and its correlation with conventional methods of fetal monitoring. In addition, an account is made of its limitations, safety, and acceptability in clinical practice. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to describe the predictive abilities of fetal pulse oximetry and its correlation with conventional methods of fetal monitoring, to define the critical threshold of fetal oxygen saturation, and to summarize the safety of fetal pulse oximetry.

Oxygen-induced lung injury in the newborn piglet.

Oxygen-induced lung toxicity was studied in artificially fed newborn miniature piglets. Paired littermates of newborn piglets were exposed to either 96-98% oxygen or air for 2, 4, 7 or 10 days. Development of pulmonary edema, as monitored by both the lung wet weight to dry weight ratio and the lung wet weight to body weight ratio, was evident 4 days after the start of oxygen exposure. Examination of light and electron micrographs showed that pulmonary edema was located mainly in the perivascular and interstitial spaces. Endothelial and type I cells were normal in appearance throughout the oxygen exposure. After exposure to 10 days of oxygen, type II cells appeared to show a decrease in the size of lamellar bodies and an increase in the number and size of mitochondria. The activity of pulmonary antioxidant defenses, as measured by the activity of superoxide dismutase (SOD), glutathione peroxidase (GP) and glutathione reductase (GR), and the level of reduced glutathione (GSH), showed a progressive increase in activity with duration of oxygen exposure, culminating in a significantly higher SOD, GP and GSH level in 7-day oxygen-exposed piglets. It is concluded that the newborn piglet is less susceptible to oxygen-induced lung injury compared to adults of other species, and the increase in the lung complement of SOD, GR, GP and GSH may contribute to the apparent resistance to oxygen toxicity.

Comparison of the up-and-down method and the fixed-dose procedure for acute oral toxicity testing.

The acute oral toxicity data for 10 compounds, generated by using two alternative methods in rats, the up-and-down method and the fixed-dose procedure, were compared with those obtained from the classical LD50 test. In this evaluation, both alternative methods offered a reduction in animal use, while providing adequate information to rank the compounds according to the EEC classification for acute oral toxicity. In addition to the ranking, these alternative methods also provided useful information on signs of toxicity and gross autopsy findings, although the results varied depending on the method used. Of the three methods, the up-and-down method required the fewest animals. Although the up-and-down method used only females, the LD50 values obtained were in good agreement with those obtained by the classical method, which used both sexes. It is concluded that the up-and-down method and the fixed-dose procedure are acceptable alternative methods to the classical LD50 test, and the choice of method depends on the type of toxicity information required.

Survey of the QSAR and in vitro approaches for developing non-animal methods to supersede the in vivo LD50 test.

Quantitative structure-activity relationship (QSAR) studies and in vitro studies in which correlations with LD50 have been sought are reviewed. QSAR methods have shown some success in relating LD50 to certain physicochemical properties of the compound, particularly lipophilicity, but have been less successful in correlating LD50 with electronic properties of molecules (related to reactivity) or structural variables. It is concluded that insufficient evidence is available to determine whether QSAR methods can be of general use in predicting the acute toxicity (LD50) of chemicals, and that until further work is undertaken to develop QSARs for a much wider range of homologous series of compounds, this situation is unlikely to be resolved. New chemical descriptors that are more directly relevant to the mechanism of toxic action of the chemical should be identified. Cytotoxicity in vitro is poorly correlated with LD50, but good correlations have been obtained between toxicity in vivo and in vitro, using systems in which the toxic endpoint reflects the probable mechanism(s) of acute toxicity of the test chemical (e.g. the assessment of neurotoxins using neural cell systems). Therefore, it seems that the successful application of in vitro methods requires a better understanding of the mechanisms of acute toxicity in vivo and the development of mammalian cell culture systems that can model more closely the metabolic fate of the chemicals in vivo.

Surfactants: a survey of short-term genotoxicity testing.

The available results for tests on over 200 surfactants in nine short-term genotoxicity assay systems were reviewed. These tests included the Salmonella/microsome mutation assay, bacterial DNA repair tests, mitotic recombination in Saccharomyces cerevisiae, the mouse lymphoma cell-mutation assay, unscheduled DNA synthesis and sister chromatid exchange assays in mammalian cells, mammalian chromosome damage tests in vitro and in vivo, the dominant lethal test in rodents, and mammalian cell-transformation tests. The collected data cover all four major classes of surfactants: anionic, cationic, nonionic and amphoteric. The results of these genotoxicity tests were overwhelmingly negative. Although there were occasional positive results in bacterial or cell-transformation systems, the testing performed to date indicates that surfactants have negligible potential to cause genetic damage. The available data also indicate that none of the assays were incompatible with testing surfactants for genotoxicity.

Intrapartum fetal oxygen saturation monitoring in a busy labour ward.

OBJECTIVE: To measure the ease of use of a fetal pulse oximeter in a busy labour ward. DESIGN: Descriptive study in the Labour Ward, National University Hospital, Singapore, involving 145 labouring women with singleton pregnancies, and fetuses in cephalic presentation, with cervical dilatation >2 cm and amniotic membranes ruptured. RESULTS: Placement was comfortable. Oxygen saturation (SpO2) readings were obtained in 127 women (87.5%). Adequate readings were obtained a median of 69% of the time the transducer was in situ. SpO2 values in the last 10 min prior to delivery correlated poorly with parameters of neonatal outcome. CONCLUSION: The Nellcor N-400 fetal pulse oximeter and FS14 fetal sensor is a feasible method of intrapartum fetal monitoring in a busy labour ward and is acceptable to labouring women.