Atopy and allergy following solid organ transplantation: A 15-year experience.

AIM: There are increasing reports of atopy/allergy following solid organ transplantation, especially paediatric liver transplantation (LT) with minimal New Zealand (NZ) data. We describe the prevalence of transplant-acquired atopy and allergy (TAA) in NZ paediatric liver transplant recipients, compared to paediatric kidney and adult liver transplants. METHODS: TAA focussed health questionnaires were sent to patients selected from the NZ transplant registry (transplanted between January 2003 and December 2017). Demographic and clinical data were also obtained from electronic health records and follow-up phone calls. RESULTS: A total of 232 patients (62% male) participated (111 adult liver, 82 paediatric liver, 39 paediatric kidney transplant recipients). Tacrolimus was primary immunosuppression for all LT patients; with combined tacrolimus, mycophenolate and corticosteroids for kidney transplants. The number of patients who developed TAA was significantly higher (P < 0.001) in the paediatric LT group (36/82, 44%) compared to adult liver (12/111, 11%) and paediatric kidney transplants (4/39, 10%). Eczema was most common (73%), then IgE-mediated food allergy (FA, 33%), allergic rhinitis (19%) and asthma (17%). Six paediatric LT recipients developed eosinophilic oesophagitis (EoE). Egg was the most common allergen in the IgE-mediated FA group. TAAs were severe enough to warrant a switch from tacrolimus to another agent in seven paediatric LT patients. For paediatric LT patients, female gender and younger age at transplant were risk factors for developing TAA. CONCLUSIONS: TAA is common in paediatric liver transplant recipients, with female gender and younger age at transplant being risk factors identified. This highlights the need for detailed atopic and allergy history to be incorporated in all pre-transplant assessments.

The effect of high-fat diet-induced metabolic disturbance on corneal neuroimmune features.

PURPOSE: The highly innervated cornea is susceptible to nerve loss secondary to systemic diseases such as diabetes and metabolic disturbances caused by high-fat diet. In this study, we characterize the effect of high-fat diet on the mouse corneal neuroimmune phenotype, including changes to corneal nerve density and resident immune cells, alongside the clinical assessment of corneal thickness and endothelial cell density. METHODS: Male C57Bl6/J mice, aged 10 weeks, were fed a high-fat diet (60 kcal% fat, 5.2 kcal/g) or control diet (10 kcal%, 3.8 kcal/g) for 16 weeks. At the study endpoint, metabolic parameters (HbA1c, weight, fasting glucose, body fat) were measured to confirm metabolic disturbance. Clinical imaging of the anterior segment was performed using optical coherence tomography to measure the corneal epithelial and stromal thickness. Corneal sensory nerves were visualized using flatmount immunostaining and confocal microscopy. The topographical distribution and density of sensory nerves (BIII-tubulin+), intraepithelial CD45+ and MHC- II+ cells, stromal macrophages (IBA1+CD206+) and endothelial cells (ZO-1+) were analysed using FIJI. RESULTS: High-fat diet mice had significantly higher blood HbA1c, higher body weight, a higher percentage of body fat and elevated fasting glucose compared to the control diet mice. Corneal epithelial and stromal thickness was similar in both groups. The sum length of the basal nerve plexus was lower in the central and peripheral cornea of mice fed a high-fat diet. In contrast, the sum length of superficial nerve terminals was similar between groups. Epithelial immune cell density was two-fold higher in the central corneas of high-fat diet mice compared to control diet mice. IBA1+CD206+ macrophage density was similar in the anterior stroma of both groups but was significantly higher in the posterior stroma of the peripheral cornea in the high-fat diet mice compared to controls. The percentage of nerve-associated MHC-II+ cells in the epithelium and stroma was higher in HFD mice compared to controls. Endothelial cell density was similar in the corneas of high-fat diet mice compared to controls. CONCLUSION: Together with corneal neuropathy, corneal immune cells in mice fed a high-fat diet were differentially affected depending on their topographical distribution and location within cornea, and appeared in closer proximity to epithelial and stromal nerves, suggesting a local neuroimmune disruption induced by systemic metabolic disturbance.

Establishment of the nasal microbiota in the first 18 months of life: Correlation with early-onset rhinitis and wheezing.

BACKGROUND: Dynamic establishment of the nasal microbiota in early life influences local mucosal immune responses and susceptibility to childhood respiratory disorders. OBJECTIVE: The aim of this case-control study was to monitor, evaluate, and compare development of the nasal microbiota of infants with rhinitis and wheeze in the first 18 months of life with those of healthy control subjects. METHODS: Anterior nasal swabs of 122 subjects belonging to the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) birth cohort were collected longitudinally over 7 time points in the first 18 months of life. Nasal microbiota signatures were analyzed by using 16S rRNA multiplexed pair-end sequencing from 3 clinical groups: (1) patients with rhinitis alone (n = 28), (2) patients with rhinitis with concomitant wheeze (n = 34), and (3) healthy control subjects (n = 60). RESULTS: Maturation of the nasal microbiome followed distinctive patterns in infants from both rhinitis groups compared with control subjects. Bacterial diversity increased over the period of 18 months of life in control infants, whereas infants with rhinitis showed a decreasing trend (P < .05). An increase in abundance of the Oxalobacteraceae family (Proteobacteria phylum) and Aerococcaceae family (Firmicutes phylum) was associated with rhinitis and concomitant wheeze (adjusted P < .01), whereas the Corynebacteriaceae family (Actinobacteria phylum) and early colonization with the Staphylococcaceae family (Firmicutes phylum; 3 weeks until 9 months) were associated with control subjects (adjusted P < .05). The only difference between the rhinitis and control groups was a reduced abundance of the Corynebacteriaceae family (adjusted P < .05). Determinants of nasal microbiota succession included sex, mode of delivery, presence of siblings, and infant care attendance. CONCLUSION: Our results support the hypothesis that the nasal microbiome is involved in development of early-onset rhinitis and wheeze in infants.

The effect of four loading intravitreal aflibercept injections on macular fluid in treatment-naïve neovascular age-related macular degeneration.

PURPOSE: To evaluate the effect of four versus three loading aflibercept injections on macular fluid resolution and visual acuity (VA) in exudative neovascular AMD (nAMD). METHODS: Multicentre, retrospective cohort study of treatment naïve nAMD eyes undergoing 3 versus 4 loading doses of aflibercept. Change in VA and fluid resolution on optical coherence tomography (OCT), were evaluated at 8 weeks post loading. The primary outcome was proportion of patients with no intraretinal (IRF) and/or subretinal (SRF) fluid at central 1 mm and whole macula at 8 weeks after loading. Data were summarised with mean ± SD for continuous variables, and n (%) for categorical variables. RESULTS: Data from 995 patients was analysed (355 patients - 4 loading doses and 640-3 loading doses). At 8 weeks post 4 loading doses proportion of eyes with neither IRF nor SRF, no IRF and no SRF were 62.8%, 88.7% and 79.2% at fovea versus 56.1%, 87.9% and 69.9% in the whole macula, respectively. Fluid resolution at both fovea and macula were significantly higher in eyes with 4 loading injections versus 3 (p = 0.0001). The mean VA change was +4.0 (±11.3) and +5.4(±13.3) letters for 3 and 4 loading doses groups (p = 0.09). CONCLUSION: Four loading dose injections of aflibercept results in higher proportion of eyes with total fluid resolution in the central subfield and total macular scan when compared to those receiving 3 loading dose injections at 8 weeks post loading phase. However, the better drying effect of 4th loading dose does not translate into better short-term VA outcomes.

Screen time and social-emotional skills in preschoolers with developmental, behavioural or emotional issues in Singapore.

Introduction: This study aimed to determine patterns of screen viewing time (SVT) in preschool children with developmental, behavioural or emotional (DBE) issues, and to identify its relationship with social-emotional development. Method: This cross-sectional study involved children aged 0-5 years who were referred to a developmental paediatric clinic for DBE issues. Parents completed a screen time questionnaire, and the Devereux Early Childhood Assessment-Clinical (DECA-C) question-naire which assessed the social-emotional competence of the children. Data were analysed using logistic regression, correlational analyses and tests of comparison. Results: Among 225 children (mean age: 32.4 months), mean daily SVT was 138 minutes. More than half (51.1%) of the children had clinical features of language delay, while 26.6% had features suggestive of autism spectrum disorder. Screen time was first introduced at a mean age of 13.8 months, with 32.4% of children previously experiencing higher SVT. Compared to SVT introduction after 1 year of age, SVT in the first 12 months was primarily to facilitate feeding (P<0.05). Children with higher past SVT had poorer attention, more aggression, and increased behavioural concerns. Children with DBE issues have significantly more screen time than same-aged peers. Conclusion: Children with DBE issues are exposed to SVT at a very young age and have significantly more screen time than their peers. It is crucial to guide parents to reduce SVT in early childhood, particularly around mealtimes.

A two-phased study on the use of remote photoplethysmography (rPPG) in paediatric care.

Background: Advancements in medical technologies have led to the development of contact-free methods of haemodynamic monitoring such as remote photoplethysmography (rPPG). rPPG uses video cameras to interpret variations in skin colour related to blood flow, which are analysed to generate vital signs readings. rPPG potentially ameliorates problems like fretfulness and fragile skin contact associated with conventional probes in children. While rPPG has been validated in adults, no prior validation has been performed in children. Methods: A two-phased prospective cross-sectional single-centre study was conducted from January to April 2023 to evaluate the feasibility, acceptability, and accuracy of obtaining heart rate (HR), respiratory rate (RR) and oxygen saturation (SpO2) using rPPG in children, compared to the current standard of care. In Phase 1, we recruited patients ≤16 years from the neonatal and paediatric wards. We excluded preterm neonates with gestational age <35 weeks and newborns <24 hours old. The rPPG webcam was positioned 30 cm from the face. After 1 minute of facial scanning, readings generated were compared with pulse oximetry for HR and SpO2, and manual counting for RR. Correlation and Bland-Altman analyses were performed. In Phase 2, we focused on the population in whom there was potential correlation between rPPG and the actual vital signs. Results: Ten neonates and 28 children aged 5 to 16 years were recruited for Phase 1 (765 datapoints). All patients were haemodynamically stable and normothermic. Patients and caregivers showed high acceptability to rPPG. rPPG values were clinically discrepant for children <10 years. For those ≥10 years, moderate correlation was observed for HR, with Spearman's correlation coefficient (Rs) of 0.50 [95% confidence intervals (CI): 0.42, 0.57]. We performed Phase 2 on 23 patients aged 12 to 16 years (559 datapoints). Strong correlation was observed for HR with Rs=0.82 (95% CI: 0.78, 0.85). There was weak correlation for SpO2 and RR (Rs=-0.25 and -0.02, respectively). Conclusions: Our study showed that rPPG is acceptable and feasible for neonates and children aged 5 to 16 years, and HR values in older children aged 12 to 16 years correlated well with the current standard. The rPPG algorithms need to be further refined for younger children, and for obtaining RR and SpO2 in all children. If successful, rPPG will provide a viable contact-free alternative for assessing paediatric vital signs, with potential use in remote monitoring and telemedicine.

Gastroesophageal reflux in the 21st century.

PURPOSE OF REVIEW: Gastroesophageal reflux (GER) remains a common, challenging problem for clinicians, with differentiation of normal development from disease a particular issue. This review updates clinicians on advances in diagnosis of GER, relationship to other problems, and current practice in management. RECENT FINDINGS: Development and understanding of multichannel intraluminal impedance-pH monitoring has given insights into the relationship of GER to symptoms. Medical treatment has changed little. Avoidance of overmedicalizing normal development is the major issue for clinicians. Laparoscopic fundoplication is established as equivalent to open fundoplication. Newer endoscopic techniques have only limited use in children to date. SUMMARY: Major changes in pediatric GER relate to understanding of physiology and relationship of GER to symptoms. The major challenge for clinicians involve differentiation of normal from abnormal GER, and applying the most relevant management.

Incarcerated hernia with ileal perforation in an extreme preterm infant.

We describe a case of a premature 24 weeks gestation infant who presented with clinical lability and abdominal distention with initial concerns of necrotising enterocolitis. On further examination, a right inguinal hernia was noted and serial abdominal X-rays showed bowel loop dilatation with intramural air and no perforation. However, the hernia was recurrent and later found to be not reducible. He underwent right groin exploration. Intraoperatively, distal ileal perforation was noted and he was found to have an additional five sites of perforation. He had a stoma sited at the left iliac fossa as well as primary anastomosis at the site of the second to fifth perforations. He had a stormy postoperative period but is currently doing well. Although obstructed hernias are rare in the initial course of an extreme preterm infant, it should not be missed as a cause of intestinal obstruction and early surgical opinion should be sought.

Length of positive surgical margins after radical prostatectomy: Does size matter? - A systematic review and meta-analysis.

OBJECTIVES: The prognostic capacity of positive surgical margins (PSM) for biochemical recurrence (BCR) is unclear, with inconsistent findings across published studies. We aimed to systematically review and perform a meta-analysis exploring the impact of Positive surgical margin length on biochemical recurrence in men after radical prostatectomy. METHODS: A search was conducted using the MEDLINE, Scopus, Embase and Cochrane databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The quality of the studies was assessed using the Newcastle-Ottawa scale, and the protocol was registered in advance (PROSPERO: CRD42020195908). This meta-analysis included 16 studies with BCR as the primary outcome measure. RESULTS: Studies used various dichotomised thresholds for PSM length. A subgroup meta-analysis was performed using the reported multivariable hazard ratio (Continuous, 3, and 1 mm PSM length). PSM length (continuous) was independently associated with an increased risk of BCR (7 studies, HR 1.04 (CI 1.02-1.05), I2 = 8% p < 0.05). PSM length greater than 3 mm conferred a higher risk of BCR compared to less than 3 mm (4 studies, HR 1.99 (1.54-2.58) I2 = 0%, p < 0.05). There was also an increased risk of BCR associated with PSM length of less than 1 mm compared to negative surgical margins (3 studies, HR 1.46 (1.05-2.04), I2 = 0%, P = 0.02). CONCLUSION: PSM length is independently prognostic for BCR after radical prostatectomy. Further long-term studies are needed to estimate the impact on systemic progression.

Reproducibility and Robustness of a Liver Microphysiological System PhysioMimix LC12 under Varying Culture Conditions and Cell Type Combinations.

The liver is one of the key organs for exogenous and endogenous metabolism and is often a target for drug- and chemical-driven toxicity. A wide range of experimental approaches has been established to model and characterize the mechanisms of drug- and chemical-induced hepatotoxicity. A number of microfluidics-enabled in vitro models of the liver have been developed, but the unclear translatability of these platforms has hindered their adoption by the pharmaceutical industry; to achieve wide use for drug and chemical safety evaluation, demonstration of reproducibility and robustness under various contexts of use is required. One of these commercially available platforms is the PhysioMimix LC12, a microfluidic device where cells are seeded into a 3D scaffold that is continuously perfused with recirculating cell culture media to mimic liver sinusoids. Previous studies demonstrated this model's functionality and potential applicability to preclinical drug development. However, to gain confidence in PhysioMimix LC12's robustness and reproducibility, supplementary characterization steps are needed, including the assessment of various human hepatocyte sources, contribution of non-parenchymal cells (NPCs), and comparison to other models. In this study, we performed replicate studies averaging 14 days with either primary human hepatocytes (PHHs) or induced pluripotent stem cell (iPSC)-derived hepatocytes, with and without NPCs. Albumin and urea secretion, lactate dehydrogenase, CYP3A4 activity, and metabolism were evaluated to assess basal function and metabolic capacity. Model performance was characterized by different cell combinations under intra- and inter-experimental replication and compared to multi-well plates and other liver platforms. PhysioMimix LC12 demonstrated the highest metabolic function with PHHs, with or without THP-1 or Kupffer cells, for up to 10-14 days. iPSC-derived hepatocytes and PHHs co-cultured with additional NPCs demonstrated sub-optimal performance. Power analyses based on replicate experiments and different contexts of use will inform future study designs due to the limited throughput and high cell demand. Overall, this study describes a workflow for independent testing of a complex microphysiological system for specific contexts of use, which may increase end-user adoption in drug development.

Triceps mass - A rare presentation of renal cell carcinoma.

Renal cell carcinoma (RCC) can commonly metastasize to the liver, lungs, bones and brain. We herein report a rare presentation of oligometastatic RCC with isolated synchronous metastasis to the triceps. A 44-year-old male presented with an enlarging mass involving the right triceps. A biopsy revealed features consistent with metastatic clear cell RCC (ccRCC). Subsequent computed tomography (CT) Imaging demonstrated a 6 cm right renal mass. He underwent a right laparoscopic radical nephrectomy which revealed a tumour stage 1b ISUP Grade 2 ccRCC. Clinicians should have a degree of suspicion for a metastatic lesion for an enlarging soft tissue mass.

Analysis of reproducibility and robustness of OrganoPlate® 2-lane 96, a liver microphysiological system for studies of pharmacokinetics and toxicological assessment of drugs.

Establishing the functionality, reproducibility, robustness, and reliability of microphysiological systems is a critical need for adoption of these technologies. A high throughput microphysiological system for liver studies was recently proposed in which induced pluripotent stem cell-derived hepatocytes (iHeps) and non-parenchymal cells (endothelial cells and THP-1 cells differentiated with phorbol 12-myristate 13-acetate into macrophage-like cells) were co-cultured in OrganoPlate® 2-lane 96 devices. The goal of this study was to evaluate this platform using additional cell types and conditions and characterize its utility and reproducibility. Primary human hepatocytes or iHeps, with and without non-parenchymal cells, were cultured for up to 17 days. Image-based cell viability, albumin and urea secretion into culture media, CYP3A4 activity and drug metabolism were assessed. The iHeps co-cultured with non-parenchymal cells demonstrated stable cell viability and function up to 17 days; however, variability was appreciable both within and among studies. The iHeps in monoculture did not form clusters and lost viability and function over time. The primary human hepatocytes in monoculture also exhibited low cell viability and hepatic function. Metabolism of various drugs was most efficient when iHeps were co-cultured with non-parenchymal cells. Overall, we found that the OrganoPlate® 2-lane 96 device, when used with iHeps and non-parenchymal cells, is a functional liver microphysiological model; however, the high-throughput nature of this model is somewhat dampened by the need for replicates to compensate for high variability.

HIDEA syndrome: A rare cause of congenital hypoventilation in a premature infant.

BACKGROUND: HIDEA (hypotonia, hypoventilation, intellectual disability, dysautonomia, epilepsy and eye abnormalities) syndrome is a rare and novel disease. We describe a premature patient who required extensive work up for his hypoventilation with a diagnosis of HIDEA syndrome. CASE DESCRIPTION: The patient was born to a pair of consanguineous parents at 32-week gestation. His intermittent bradypnoea requiring significant respiratory support during his postnatal clinical course was atypical for bronchopulmonary dysplasia and this required further extensive work up to look for a cause for his hypoventilation. A trio whole exon sequencing was done which identified homozygous variants in P4HTM, in keeping with the diagnosis of autosomal recessive HIDEA syndrome. He is currently doing well on BiPAP 18 cm H2O / 8 cm H2O, Rate 30 breaths per minute in room air and full nasogastric feeding. He also has cortical blindess and severe global developmental delay. CONCLUSION: Early diagnosis is crucial to optimise adequate ventilatory management including early tracheostomy as many require lifelong continuous or intermittent ventilation. This minimises the complications of chronic hypoxia and reduces mortality risk.

Decreased memory B cell frequencies in COVID-19 delta variant vaccine breakthrough infection.

The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor-binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1ß and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.

Lower vaccine-acquired immunity in the elderly population following two-dose BNT162b2 vaccination is alleviated by a third vaccine dose.

Understanding the impact of age on vaccinations is essential for the design and delivery of vaccines against SARS-CoV-2. Here, we present findings from a comprehensive analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 SARS-CoV-2 mRNA vaccine. Two vaccine doses induce high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of the Delta and Omicron variants is less efficient than that of the ancestral Wuhan strain. Age-stratified analyses identify a group of low antibody responders where individuals ≥60 years are overrepresented. Waning of the antibody and cellular responses is observed in 30% of the vaccinees after 6 months. However, age does not influence the waning of these responses. Taken together, while individuals ≥60 years old take longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at 6 months post-vaccination. A third dose strongly boosts the low antibody responses in the older individuals against the ancestral Wuhan strain, Delta and Omicron variants.

Epidemiology and Management of Children with Hypertensive Crisis: A Single-Center Experience.

Most children who present with hypertensive crisis have a secondary cause for hypertension. This study describes the epidemiology and management of children with hypertensive crisis. A retrospective cohort study was done in a tertiary pediatric hospital from 2009 to 2015. Thirty-seven patients were treated for hypertensive crisis. Twelve (32.4%) patients were treated for hypertensive emergency. The majority of our patients (33 [89.1%]) had a secondary cause of hypertension. The most common identifiable cause of hypertension was a renal pathology (18/37 [48.6%]). Oral nifedipine (23 [62.1%]) was the most frequently used antihypertensive, followed by intravenous labetalol (8 [21.6%]). There were no mortalities or morbidities. Hypertensive crisis in children is likely secondary in nature. Oral nifedipine and intravenous labetalol are both effective treatments.