In Situ Synthesis and Self-Assembly of Peptide-PEG Conjugates: A Facile Method for the Construction of Fibrous Hydrogels.

Peptide-based hydrogels have gained considerable attention as a compelling platform for various biomedical applications in recent years. Their attractiveness stems from their ability to seamlessly integrate diverse properties, such as biocompatibility, biodegradability, easily adjustable hydrophilicity/hydrophobicity, and other functionalities. However, a significant drawback is that most of the functional self-assembling peptides cannot form robust hydrogels suitable for biological applications. In this study, we present the synthesis of novel peptide-PEG conjugates and explore their comprehensive hydrogel properties. The hydrogel comprises double networks, with the first network formed through the self-assembly of peptides to create a ß-sheet secondary structure. The second network is established through covalent bond formation via N-hydroxysuccinimide chemistry between peptides and a 4-arm PEG to form a covalently linked network. Importantly, our findings reveal that this hydrogel formation method can be applied to other peptides containing lysine-rich sequences. Upon encapsulation of the hydrogel with antimicrobial peptides, the hydrogel retained high bacterial killing efficiency while showing minimum cytotoxicity toward mammalian cells. We hope that this method opens new avenues for the development of a novel class of peptide-polymer hydrogel materials with enhanced performance in biomedical contexts, particularly in reducing the potential for infection in applications of tissue regeneration and drug delivery.

A homozygous missense variant in the YG box domain in an individual with severe spinal muscular atrophy: a case report and variant characterization.

The vast majority of severe (Type 0) spinal muscular atrophy (SMA) cases are caused by homozygous deletions of survival motor neuron 1 (SMN1). We report a case in which the patient has two copies of SMN1 but clinically presents as Type 0 SMA. The patient is an African American male carrying a homozygous maternally inherited missense variant (c.796T>C) in a cis-oriented SMN1 duplication on one chromosome and an SMN1 deletion on the other chromosome (genotype: 2*+0). Initial extensive genetic workups including exome sequencing were negative. Deletion analysis used in the initial testing for SMA also failed to detect SMA as the patient has two copies of SMN1. Because of high clinical suspicion, SMA diagnosis was finally confirmed based on full-length SMN1 sequencing. The patient was initially treated with risdiplam and later gene therapy with onasemnogene abeparvovec at 5 months without complications. The patient's muscular weakness has stabilized with mild improvement. The patient is now 28 months old and remains stable and diffusely weak, with stable respiratory ventilatory support. This case highlights challenges in the diagnosis of SMA with a non-deletion genotype and provides a clinical example demonstrating that disruption of functional SMN protein polymerization through an amino acid change in the YG-box domain represents a little known but important pathogenic mechanism for SMA. Clinicians need to be mindful about the limitations of the current diagnostic approach for SMA in detecting non-deletion genotypes.

Preoperative considerations and benefits of neoadjuvant chemotherapy: insights from a 12-year review of the Hong Kong Breast Cancer Registry.

INTRODUCTION: Neoadjuvant chemotherapy (NAC) was initially used for locally advanced or inoperable breast cancers. Its extension to early disease has facilitated breast-conserving surgery (BCS). This study investigated the use of NAC in patients registered with the Hong Kong Breast Cancer Registry (HKBCR); it also assessed NAC effectiveness according to rates of pathological complete response (pCR) and BCS. METHODS: Records were retrieved from the HKBCR regarding 13 435 women who had been diagnosed with invasive breast cancer during the period of 2006 to 2017, including 1084 patients who received NAC. RESULTS: The proportion of patients treated with NAC nearly doubled from 5.6% in 2006-2011 to 10.3% in 2012-2017. The increase was most pronounced among patients with stage II or III disease. In terms of biological subtype, substantial increases in the receipt of NAC were evident among patients with triple-negative and human epidermal growth factor receptor 2 (HER2)-positive (non-luminal) tumours. The best rates of pCR were observed in patients with HER2-positive (non-luminal) [46.0%] tumours, followed by patients with luminal B (HER2-positive) [29.4%] and triple-negative (29.3%) tumours. After NAC, the rate of BCS was 53.9% in patients with clinical stage IIA disease, compared with 38.2% in patients with pathological stage IIA disease who did not receive NAC. CONCLUSION: The use of NAC in Hong Kong increased from 2006 to 2017. The findings regarding rates of pCR and BCS indicate that NAC is an effective treatment; it should be considered in patients with stage ≥II disease, as well as patients with HER2- positive (non-luminal) or triple-negative breast cancers.

Clinical validity assessment of genes frequently tested on intellectual disability/autism sequencing panels.

PURPOSE: Neurodevelopmental disorders (NDDs), such as intellectual disability (ID) and autism spectrum disorder (ASD), exhibit genetic and phenotypic heterogeneity, making them difficult to differentiate without a molecular diagnosis. The Clinical Genome Resource Intellectual Disability/Autism Gene Curation Expert Panel (GCEP) uses systematic curation to distinguish ID/ASD genes that are appropriate for clinical testing (ie, with substantial evidence supporting their relationship to disease) from those that are not. METHODS: Using the Clinical Genome Resource gene-disease validity curation framework, the ID/Autism GCEP classified genes frequently included on clinical ID/ASD testing panels as Definitive, Strong, Moderate, Limited, Disputed, Refuted, or No Known Disease Relationship. RESULTS: As of September 2021, 156 gene-disease pairs have been evaluated. Although most (75%) were determined to have definitive roles in NDDs, 22 (14%) genes evaluated had either Limited or Disputed evidence. Such genes are currently not recommended for use in clinical testing owing to the limited ability to assess the effect of identified variants. CONCLUSION: Our understanding of gene-disease relationships evolves over time; new relationships are discovered and previously-held conclusions may be questioned. Without periodic re-examination, inaccurate gene-disease claims may be perpetuated. The ID/Autism GCEP will continue to evaluate these claims to improve diagnosis and clinical care for NDDs.

Quality of life and defecative function 10 years or longer after posterior sagittal anorectoplasty and laparoscopic-assisted anorectal pull-through for anorectal malformation.

PURPOSE: In our center, patients with anorectal malformation, including males with recto-vesical (RV)/recto-bladder neck (RBN)/recto-prostatic urethral (RU) fistulas, and females with recto-vaginal (RV) fistulas have been treated by posterior sagittal anorectoplasty (PSARP) before 2000, and by laparoscopic-assisted anorectal pull-through (LAARP) thereafter. We would like to compare the quality of life (QOL) and long-term defecative function between these two groups of patients 10 years after reconstructive surgery. METHODS: Patients who underwent LAARP between 2001 and 2005 were compared with historical controls treated with PSARP between 1996 and 2000. Degrees of continence were graded by the Krickenbeck classification and Kelly's score. QOL was assessed by Hirschsprung's disease/Anorectal Malformation Quality of Life (HAQL) questionnaire. Results were compared using Chi-square test and t test. RESULTS: There were 14 LAARP and 7 PSARP patients. All attained voluntary bowel movements. Moderate to severe soiling (Krickenbeck Grade 2 and 3) was found in 3/14 LAARP (21.4%) and 1/7 PSARP (14.3%) patients, p = 1.00. Constipation requiring use of laxatives was present in 3/14 LAARP (28.6%) and 1/7 PSARP (14.3%) patients, p = 0.62. Mean Kelly's scores were 3.79 ± 0.98 (LAARP) and 4.71 ± 1.25 (PSARP), p = 0.12. No patient required Malone antegrade continence enema (MACE). The QOL scores based on the HAQL questionnaire were comparable between the two groups in all areas except social functioning, in which the LAARP patients attained a significantly lower mean score (26.4 vs 71.7, p = 0.0001). CONCLUSION: The 10-year outcome between LAARP and PSARP patients in terms of QOL and defecative function is comparable. Impairment in social functioning in these patients is reflected by the self-reported lower level of functioning.

Spatial variation of pneumonia hospitalization risk in Twin Cities metro area, Minnesota.

Fine resolution spatial variability in pneumonia hospitalization may identify correlates with socioeconomic, demographic and environmental factors. We performed a retrospective study within the Fairview Health System network of Minnesota. Patients 2 months of age and older hospitalized with pneumonia between 2011 and 2015 were geocoded to their census block group, and pneumonia hospitalization risk was analyzed in relation to socioeconomic, demographic and environmental factors. Spatial analyses were performed using Esri's ArcGIS software, and multivariate Poisson regression was used. Hospital encounters of 17 840 patients were included in the analysis. Multivariate Poisson regression identified several significant associations, including a 40% increased risk of pneumonia hospitalization among census block groups with large, compared with small, populations of ⩾65 years, a 56% increased risk among census block groups in the bottom (first) quartile of median household income compared to the top (fourth) quartile, a 44% higher risk in the fourth quartile of average nitrogen dioxide emissions compared with the first quartile, and a 47% higher risk in the fourth quartile of average annual solar insolation compared to the first quartile. After adjusting for income, moving from the first to the second quartile of the race/ethnic diversity index resulted in a 21% significantly increased risk of pneumonia hospitalization. In conclusion, the risk of pneumonia hospitalization at the census-block level is associated with age, income, race/ethnic diversity index, air quality, and solar insolation, and varies by region-specific factors. Identifying correlates using fine spatial analysis provides opportunities for targeted prevention and control.

Evaluating the Clinical Validity of Gene-Disease Associations: An Evidence-Based Framework Developed by the Clinical Genome Resource.

With advances in genomic sequencing technology, the number of reported gene-disease relationships has rapidly expanded. However, the evidence supporting these claims varies widely, confounding accurate evaluation of genomic variation in a clinical setting. Despite the critical need to differentiate clinically valid relationships from less well-substantiated relationships, standard guidelines for such evaluation do not currently exist. The NIH-funded Clinical Genome Resource (ClinGen) has developed a framework to define and evaluate the clinical validity of gene-disease pairs across a variety of Mendelian disorders. In this manuscript we describe a proposed framework to evaluate relevant genetic and experimental evidence supporting or contradicting a gene-disease relationship and the subsequent validation of this framework using a set of representative gene-disease pairs. The framework provides a semiquantitative measurement for the strength of evidence of a gene-disease relationship that correlates to a qualitative classification: "Definitive," "Strong," "Moderate," "Limited," "No Reported Evidence," or "Conflicting Evidence." Within the ClinGen structure, classifications derived with this framework are reviewed and confirmed or adjusted based on clinical expertise of appropriate disease experts. Detailed guidance for utilizing this framework and access to the curation interface is available on our website. This evidence-based, systematic method to assess the strength of gene-disease relationships will facilitate more knowledgeable utilization of genomic variants in clinical and research settings.

A prospective interventional study to examine the effect of a silver alloy and hydrogel-coated catheter on the incidence of catheter-associated urinary tract infection.

INTRODUCTION: Catheter-associated urinary tract infection is a major hospital-acquired infection. This study aimed to analyse the effect of a silver alloy and hydrogel-coated catheter on the occurrence of catheter-associated urinary tract infection. METHODS: This was a 1-year prospective study conducted at a single centre in Hong Kong. Adult patients with an indwelling urinary catheter for longer than 24 hours were recruited. The incidence of catheter-associated urinary tract infection in patients with a conventional latex Foley catheter without hydrogel was compared with that in patients with a silver alloy and hydrogel-coated catheter. The most recent definition of urinary tract infection was based on the latest surveillance definition of the National Healthcare Safety Network managed by Centers for Disease Control and Prevention. RESULTS: A total of 306 patients were recruited with a similar ratio between males and females. The mean (standard deviation) age was 81.1 (10.5) years. The total numbers of catheter-days were 4352 and 7474 in the silver-coated and conventional groups, respectively. The incidences of catheter-associated urinary tract infection per 1000 catheter-days were 6.4 and 9.4, respectively (P=0.095). There was a 31% reduction in the incidence of catheter-associated urinary tract infection per 1000 catheter-days in the silver-coated group. Escherichia coli was the most commonly involved pathogen (36.7%) of all cases. Subgroup analysis revealed that the protective effect of silver-coated catheter was more pronounced in long-term users as well as female patients with a respective 48% (P=0.027) and 42% (P=0.108) reduction in incidence of catheter-associated urinary tract infection. The mean catheterisation time per person was the longest in patients using a silver-coated catheter (17.0 days) compared with those using a conventional (10.8 days) or both types of catheter (13.6 days) [P=0.01]. CONCLUSIONS: Silver alloy and hydrogel-coated catheters appear to be effective in preventing catheter-associated urinary tract infection based on the latest surveillance definition. The effect is perhaps more prominent in long-term users and female patients.

Is congenital pulmonary airway malformation really a rare disease? Result of a prospective registry with universal antenatal screening program.

BACKGROUND: Congenital pulmonary airway malformation (CPAM) is an increasingly recognized disease with potential mortality. Owing to limited published studies, the true incidence is yet to be determined. We carried out this prospective study with the aim to estimate its true incidence on a population basis. METHODS: An antenatal ultrasonography program was implemented since 2009. Fetuses with suspected intra-thoracic lesions were monitored by regular follow-ups. Antenatal course, postnatal outcomes, and other demographics were compared to those of patients with CPAM in the previous decades (1989-2008). The incidence of CPAM was calculated in different periods. RESULTS: 66 CPAM patients were identified between 2009 and 2014 with 62 patients being detected by antenatal scan. In contrast, 45 patients were identified between 1989 and 2008 with 27 patients being detected antenatally. The incidence rate during the past and recent period was estimated as ~1 in 27,400 and ~1 in 7200 live births, respectively (p = 0.024). CONCLUSION: With increasing awareness of clinicians and the universal use of latest ultrasound technology, it is likely that more CPAM cases will be detected in the future. Here, we presented our best estimated incidence rate of CPAM, yet only a larger scale study can reveal its true incidence.

Galactocele in a Male Infant with Transient Hyperprolactinaemia: An Extremely Rare Cause of Breast Enlargement in Children.

Galactocele is a rare breast condition in infants. Here, we report a 16-month-old boy who developed progressive left breast enlargement. Ultrasonography and magnetic resonance imaging revealed a 4 cm cystic lesion at left breast. Hormonal assay showed transient hyperprolactinaemia with no known cause identified. Subsequently, galactocele was confirmed on histopathological examination after complete surgical excision. No recurrence was observed on regular follow-up.

Sperm retrieval rate and pregnancy rate in infertile couples undergoing in-vitro fertilisation and testicular sperm extraction for non-obstructive azoospermia in Hong Kong.

OBJECTIVE: There are currently no local data on the sperm retrieval and pregnancy rates in in-vitro fertilisation and testicular sperm extraction cycles, especially with regard to the presence of genetic abnormalities. This study aimed to determine the sperm retrieval and pregnancy rates in infertile couples who underwent in-vitro fertilisation and testicular sperm extraction for non-obstructive azoospermia. METHODS: This retrospective case series was conducted at a tertiary assisted reproduction unit in Hong Kong. Men with non-obstructive azoospermia who underwent in-vitro fertilisation and testicular sperm extraction between January 2001 and December 2013 were included. The main outcome measures were sperm retrieval and pregnancy rates. RESULTS: During the study period, 89 men with non-obstructive azoospermia underwent in-vitro fertilisation and testicular sperm extraction. Sperm was successfully retrieved in 40 (44.9%) men. There was no statistically significant difference in the sperm retrieval rate of those with karyotypic abnormalities (2/5, 40.0% vs 28/61, 45.9%; P=1.000) and AZFc microdeletion (3/6, 50.0% vs 28/61, 45.9%; P=1.000) compared with those without. Sperms were successfully retrieved in patients who had mosaic Klinefelter syndrome (2/3, 66.7%) but not in the patient with non-mosaic Klinefelter syndrome. No sperms were found in men with AZFa or AZFb microdeletions. Pregnancy test was positive in 15 (16.9%) patients and the clinical pregnancy rate was 13.5% (12/89) per cycle. The clinical pregnancy rate per transfer was 34.3% (12/35). CONCLUSIONS: The sperm retrieval rate and clinical pregnancy rate per initiated cycle in men undergoing in-vitro fertilisation and testicular sperm extraction in our unit were 44.9% and 13.5%, respectively. No sperms could be retrieved in the presence of AZFa and AZFb microdeletions, but karyotype and AZFc microdeletion abnormalities otherwise did not predict the success of sperm retrieval in couples undergoing in-vitro fertilisation and testicular sperm extraction. Genetic tests are important prior to testicular sperm extraction for patient selection and genetic counselling.

Silver containing hydrofiber dressing promotes wound healing in paediatric patients with partial thickness burns.

INTRODUCTION: Burn injury is one of the most common reasons for admission in paediatric population. There is currently no international consensus on the best wound dressing material. Aquacel Ag, a new silver containing hydrofiber dressing material has been reported to produce good clinical results. Yet, only a limited number of studies exist in the paediatric population. This study aims to review our experience of burn management over the past 5 years and to evaluate the effectiveness of Aquacel Ag in the management of partial thickness burns. METHODS: A retrospective review of all patients admitted for burn injury between January 2010 and December 2014 was conducted. Patients' demographics, mechanism of injury, body surface areas involved, treatment applied, and clinical outcomes were analyzed. Patients with superficial injury, full thickness burns that required surgical debridement, burn area less than 2 % or more than 25 % of total body surface area, or incomplete clinical data were excluded from the comparative study. RESULTS: A total of 119 patients were identified. 114 (96 %) was due to domestic injury, of which 108 (91 %) was food-related. The most commonly affected areas were limbs (n = 89, 74.8 %), followed by trunk (n = 62, 74.8). 84 patients fulfilled the inclusion criteria and were recruited into the study. 31 patients received Aquacel Ag dressing and 53 patients received standard paraffin gauze dressing. The two groups showed no statistical difference in age, sex, percentage of total body surface area involved, and infection rate. Outcomes of patients treated with Aquacel Ag were compared with patients treated with standard dressing. The mean hospital stay was significantly shorter for the Aquacel Ag group (14.26 vs 23.45, p = 0.045). Aquacel Ag group required much less frequent dressing change (5.67 vs 20.59, p = 0.002). 5 patients in standard dressing group developed hypertrophic scar and required prolonged pressure garment, whereas only one hypertrophic scar was observed in the Aquacel Ag group. CONCLUSION: Aquacel Ag appears to promote early burn wound healing with less hypertrophic scar formation.

Correction: "Childhood intussusception: 17-year experience at a tertiary referral centre in Hong Kong.

[This corrects the article DOI: 10.12809/hkmj144456].

Preventing Infections in Sickle Cell Disease: The Unfinished Business.

While encapsulated bacterial agents, particularly Streptococcus pneumoniae, are recognized as important microbes that are associated with serious illness in hosts with sickle cell disease (SCD), multiple pathogens are implicated in infectious manifestations of SCD. Variations in clinical practice have been an obstacle to the universal implementation of infection preventive management through active, targeted vaccination of these individuals and routine usage of antibiotic prophylaxis. Paradoxically, in low-income settings, there is evidence that SCD also increases the risk for several other infections that warrant additional infection preventive measures. The infection preventive care among patients with SCD in developed countries does not easily translate to the adoption of these recommendations globally, which must take into account the local epidemiology of infections, available vaccines and population-specific vaccine efficacy, environment, health care behaviors, and cultural beliefs, as these are all factors that play a complex role in the manifestation of SCD and the prevention of infectious disease morbidity.

An ecological analysis of pertussis disease in Minnesota, 2009-2013.

The increase in pertussis cases in Minnesota in the last decade has been mainly attributed to the switch from whole cell to acellular pertussis [as part of the diphtheria, tetanus and acellular pertussis vaccine (DTaP)]. It is unclear, however, to what degree community-level risk factors also contribute. Understanding these factors can help inform public health policy-makers about where else to target resources. We performed an ecological analysis within Minnesota to identify risk factors at the county level using a Bayesian Poisson generalized linear areal model to account for spatial dependence. Univariate analyses suggested an association between increased pertussis rates at the county level and white maternal ethnicity, being US born, urban counties and average household size. In the multivariable analysis, the rate of pertussis was 1·79 times greater for urban vs. rural counties and 4·75 times greater for counties with a one-person larger average household size. Pertussis rates in counties with higher (i.e. 4+DTaP) receipt in children were 0·97 times lower. Examining county-level factors associated with varying levels of pertussis may help identify those counties that would most benefit from targeted interventions and increased resource allocation.

The feasibility and efficacy of multi-channel intraluminal impedance monitoring in children.

INTRODUCTION: The diagnosis of gastro-oesophageal reflux is currently based on clinical presentation and oesophageal pH monitoring. In recent years, the use of multi-channel intraluminal impedance (MII) monitoring has gained increasing attention in the adult population. However, its use in the paediatric population is still in the developing stage with only limited number of publications. This study aims to review our early experience of MII application in children. METHODS: A retrospective study of all patients who underwent MII monitoring between 2011 and 2014 at a tertiary referral centre was performed. Patients' medical records were reviewed with demographic data extracted. Number of reflux episodes and other MII parameters were analysed. RESULTS: In total, 34 patients were identified during the study period, with 20 males and 14 females. Indication for study included previous aspiration pneumonia (n = 13), persistent reflux or vomiting symptom (n = 10) and as part of routine assessment before gastrostomy (n = 11). At the time of study the average age was 69 months (range 9-216 months). 28 patients showed significant gastro-oesophageal reflux. On average patient has 36.1 acidic and 22.3 non-acidic reflux episodes during the 24 h monitoring period. Non-acidic reflux accounts for 38.1 % of the overall reflux episodes. The sensitivity of MII monitoring to detect reflux was higher compared to conventional pH study (73 vs 50 %, p = 0.1). CONCLUSION: MII monitoring is safe and feasible in children. Non-acid reflux should not be underestimated in paediatric population. MII appears to be more sensitive than conventional pH monitoring in our study, but its true significance is yet to be confirmed by larger study in the future.