Height-based formulas for predicting intravascular length of tunnelled neck central venous catheter in paediatric population.

INTRODUCTION: Central venous catheter (CVC) placement is commonly performed in children. We aim to develop simple formulas to predict CVC intravascular length to minimise radiation exposure associated with the procedure. METHODS: 124 paediatric patients who received tunnelled neck CVCs and subsequent CT thorax at Hong Kong Children's Hospital from January 2020 to July 2022 were reviewed retrospectively. Formula development cohorts were subdivided by insertion sites-9 right external jugular vein (REJV), 41 right internal jugular vein (RIJV), 14 left external jugular vein (LEJV), 10 left internal jugular vein (LIJV). Using measurements from CT by two radiologists, formulas predicting the CVC intravascular length based on height and insertion sites were developed using a linear regression model. These formulas were tested with validation cohorts (10 randomly selected cases in REJV and RIJV groups respectively). Validation cohorts were not available for LEJV and LIJV groups due to small sample sizes. RESULT: The goodness-of-fit (R^2) of all formulas are above 0.8. In the validation cohorts, the REJV formula was predictive of intravascular CVC length within 1 cm in 70% of CVC with mean absolute difference of 0.63 cm (SD 0.48 cm), and the RIJV formula was predictive of intravascular CVC length within 1 cm in 80% of CVC with mean absolute difference of 0.67 cm (SD 0.53 cm). CONCLUSION: Intravascular CVC length can be estimated using simple formulas based on height and insertion sites. Further prospective validation of the LEJV and LIJV formulas is needed.

Comparison of central corneal thickness measurements using three different imaging devices.

PURPOSE: The purpose of this study was to compare central corneal thickness (CCT) values and evaluate the agreement obtained with three different devices in healthy eyes. METHODS: A total of 120 eyes of 60 healthy individuals (36 men and 24 women) were enrolled in this retrospective study. CCT measurements were performed using an optical biometer (AL-Scan), spectral-domain optical coherence tomography (SD-OCT) (Topcon 3D) and ultrasonic pachymetry (UP) (Accupach VI), and the results were compared. Bland-Altman analysis was used to quantify the agreement between methods. MAIN RESULTS: The mean patient age was 28±5.73years (18-40years). The mean CCT values obtained by AL-Scan, UP, and SD-OCT were 532.4µm±29.7, 549µm±30.4, and 547µm±30.6, respectively. The mean differences in CCT were 15.30±9.52µm between AL-Scan and OCT (P<0.01), 17.15±8.42µm between AL-Scan and UP (P<0.01), and 1.85± 8.78µm between UP and OCT (P=0.067). All three methods of CCT measurement were closely correlated with each other. CONCLUSION: The present study results suggest that, despite good agreement between the three devices, AL-Scan significantly underestimated CCT compared to UP and OCT. Therefore, clinicians should be aware that different results can be obtained using different devices for CCT measurements. It would be a better approach not to use them as interchangeable in clinical practice. CCT examination and follow-up should be performed using the same device, especially for patients who will undergo refractive surgery.

Giant Biquadratic Exchange in 2D Magnets and Its Role in Stabilizing Ferromagnetism of NiCl_{2} Monolayers.

Two-dimensional (2D) van der Waals (vdW) magnets provide an ideal platform for exploring, on the fundamental side, new microscopic mechanisms and for developing, on the technological side, ultracompact spintronic applications. So far, bilinear spin Hamiltonians have been commonly adopted to investigate the magnetic properties of 2D magnets, neglecting higher order magnetic interactions. However, we here provide quantitative evidence of giant biquadratic exchange interactions in monolayer NiX_{2} (X=Cl, Br and I), by combining first-principles calculations and the newly developed machine learning method for constructing Hamiltonian. Interestingly, we show that the ferromagnetic ground state within NiCl_{2} single layers cannot be explained by means of the bilinear Heisenberg Hamiltonian; rather, the nearest-neighbor biquadratic interaction is found to be crucial. Furthermore, using a three-orbitals Hubbard model, we propose that the giant biquadratic exchange interaction originates from large hopping between unoccupied and occupied orbitals on neighboring magnetic ions. On a general framework, our work suggests biquadratic exchange interactions to be important in 2D magnets with edge-shared octahedra.

Selective stimulation of the JAK/STAT signaling pathway by silica nanoparticles in human endothelial cells.

Silica nanoparticles (SiNP) are frequently used in pharmaceutical formulations. Intravenously administered, these particles are in close contact with the vascular endothelium. However, preliminary safety assessments of these novel excipients have indicated that SiNP are potentially cytotoxic and can trigger inflammation. In order to elucidate mechanisms of SiNP mediated inflammation, cerebral microvascular endothelial cells and primary umbilical endothelial cells were incubated with SiNP at doses between 10ng/ml and 250µg/ml. Two types of 110nm SiNP with different surface charge were synthesized and characterized. Uptake, cell viability, apoptosis, necrosis, oxidative stress, as well as interferences with both JAK/STAT and NF-κB pathways were studied. SiNP uptake leads to a cell viability decrease and promotes generation of reactive oxygen species (ROS) in a time- and dose-dependent manner. Furthermore, SiNP are able to trigger the activation of the STAT1 pathway. In contrast, no significant activation of STAT3, STAT6 or NF-κB could be detected. Additionally, modulation of the major histocompatibility complex (MHC) class I proteins was observed for cationic SiNP at low doses. Our results show the potential of SiNP to trigger selective activation of inflammatory signaling pathways in endothelial cells and thereby contribute to a better understanding of the toxicological profile of SiNP.

Magnetic resonance imaging of the fetal brain.

INTRODUCTION: This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. METHODS: We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. RESULTS: One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. CONCLUSIONS: Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

Developmental Trajectories for Visuo-Spatial Attention are Altered by Prenatal Alcohol Exposure: A Longitudinal FMRI Study.

Functional magnetic resonance imaging (fMRI) reveals brain activation abnormalities during visuo-spatial attention and working memory among those with fetal alcohol spectrum disorders (FASD) in cross-sectional reports, but little is known about how activation changes over time during development within FASD or typically developing children. We studied 30 controls and 31 individuals with FASD over 2 years (7-14 years at first participation) with a total of 122 scans, as part of the Collaborative Initiative on Fetal Alcohol Spectrum Disorders. Despite comparable performance, there were significant group differences in visuo-spatial activation over time bilaterally in frontal, parietal, and temporal regions. Controls showed an increase in signal intensity in these multiple regions whereas FASD participants showed a decrease in brain activation. Effects were also found in 2 small independent samples from the USA, corroborating the findings from the larger group. Results suggest that the long-lasting effect of prenatal alcohol may impact the maturation of visuo-spatial attention and differentiate those with FASD from controls. Based on this first longitudinal fMRI study in FASD children, our novel findings suggest a possible neural mechanism for attention deficits common among individuals with FASD.

Effects of prenatal alcohol exposure on the development of white matter volume and change in executive function.

Prenatal alcohol exposure can cause a wide range of deficits in executive function that persist throughout life, but little is known about how changes in brain structure relate to cognition in affected individuals. In the current study, we predicted that the rate of white matter volumetric development would be atypical in children with fetal alcohol spectrum disorders (FASD) when compared to typically developing children, and that the rate of change in cognitive function would relate to differential white matter development between groups. Data were available for 103 subjects [49 with FASD, 54 controls, age range 6-17, mean age = 11.83] with 153 total observations. Groups were age-matched. Participants underwent structural magnetic resonance imaging (MRI) and an executive function (EF) battery. Using white matter volumes measured bilaterally for frontal and parietal regions and the corpus callosum, change was predicted by modeling the effects of age, intracranial volume, sex, and interactions with exposure status and EF measures. While both groups showed regional increases in white matter volumes and improvement in cognitive performance over time, there were significant effects of exposure status on age-related relationships between white matter increases and EF measures. Specifically, individuals with FASD consistently showed a positive relationship between improved cognitive function and increased white matter volume over time, while no such relationships were seen in controls. These novel results relating improved cognitive function with increased white matter volume in FASD suggest that better cognitive outcomes could be possible for FASD subjects through interventions that enhance white matter plasticity.

Cardiac structure and functions in patients with asymptomatic primary hyperparathyroidism.

BACKGROUND: The data about cardiovascular (CV) changes in patients with asymptomatic primary hyperparathyroidism (PHPT) are scarce. AIM: The aim of this study is to compare cardiac structure and functions in patients with asymptomatic PHPT and controls by using tissue Doppler echocardiography. SUBJECTS AND METHODS: Thirty-eight patients with asymptomatic PHPT and 31 sex- and age-matched controls with similar cardiac risk factors were evaluated. RESULTS: There was no significant difference in ejection fraction (EF) between the patients and the controls [64±5.95 vs 62±3.25% (p=0.094)]. Left ventricular mass index (LVMI) was significantly higher in patients than controls [105.96 (66.45-167.24) vs 93.79 (64.25- 139.25) g/m2, p=0.014]. There was a significant correlation between LVMI and serum calcium (Ca) (r=0.240, p<0.005). Myocardial performance index (MPI) was significantly higher in patients than controls [0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p<0.001]. There was positive correlation between theMPI and serumCa levels (r=0.505, p<0.001), parathyroid hormone (PTH) levels (r=0.464, p<0.001) and LVMI (r=0.270, p<0.005). When the normotensive patients and controls were evaluated, the difference between the groups remained statistically significant considering LVMI and MPI [109 (66.45-167.24) g/m2 vs 94.17 (64.25-75.10) g/m2, p=0.03; and 0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p<0.01, respectively]. There were significant correlations between MPI and Ca (r=0.566, p<0.001), and PTH (r=0.472, p<0.001). CONCLUSIONS: Our study results showed that cardiacmorphology and diastolic functions are altered in the patients with asymptomatic PHPT. High serum PTH and Ca levels may have an impact on these CV changes. Whether these subtle CV changes would affect cardiac systolic functions and mortality in patients with asymptomatic PHPT should be investigated in further prospective studies.

Assessment of balance performance and fear of falling in acromegalic patients: a comparative study.

BACKGROUND: Acromegaly may lead to balance disturbances and fear of falling due to changes in body composition and co-morbidities. AIM: The aim of this study was to evaluate balance and fear of falling in acromegalic patients and their relation with disease characteristics. MATERIALS AND METHODS: Forty-eight acromegalic patients and 41 age- and gender-matched controls were enrolled in the study. The median ages of the patients and controls were 48 (25-75) and 50 (25-67) yr, respectively. Berg Balance Scale (BBS) and one-leg stance test (OLST) were used to compare dynamic and static balance respectively, 50 meters walking test was used to compare functional capacity and falls efficacy scale-international (FES-I) was used to compare fear of falling between the groups. RESULTS: Balance tests (BBS and 50 meter walking test) and fear of falling (FES-I) were significantly disturbed in patients compared with controls. There was no significant difference in OLST. BBS and OLST were negatively and FES-I was positively correlated with age. FES-I was negatively correlated with BBS and OLST was positively correlated with 50 meters walking test. Only OLST was negatively correlated with disease duration. Logistic regression analysis revealed that balance was not affected by the presence of co-morbidities, postoperative vision loss and disease control. CONCLUSIONS: This is the first study showing that balance is disturbed in acromegalic patients. This disturbance is not related to disease control and co-morbidities but somewhat to disease duration.

Combat-training increases intestinal permeability, immune activation and gastrointestinal symptoms in soldiers.

BACKGROUND: Gastrointestinal (GI) symptoms are common in soldiers in combat or high-pressure operational situations and often lead to compromised performance. Underlying mechanisms are unclear, but neuroendocrine dysregulation, immune activation and increased intestinal permeability may be involved in stress-related GI dysfunction. AIM: To study the effects of prolonged, intense, mixed psychological and physical stress on intestinal permeability, systemic inflammatory and stress markers in soldiers during high-intensity combat-training. METHODS: In 37 male army medical rapid response troops, GI symptoms, stress markers, segmental intestinal permeability using the 4-sugar test (sucrose, lactulose, mannitol and sucralose) and immune activation were assessed during the 4th week of an intense combat-training and a rest period. RESULTS: Combat-training elicited higher stress, anxiety and depression scores (all P < 0.01) as well as greater incidence and severity of GI symptoms [irritable bowel syndrome symptom severity score (IBS-SSS), P < 0.05] compared with rest. The IBS-SSS correlated with depression (r = 0.41, P < 0.01) and stress (r = 0.40, P < 0.01) ratings. Serum levels of cortisol, interleukin-6, and tumour necrosis factor-α, and segmental GI permeability increased during combat-training compared with rest (all P < 0.05). The lactulose:mannitol ratio was higher in soldiers with GI symptoms (IBS-SSS ≥75) during combat-training than those without (IBS-SSS <75) (P < 0.05). CONCLUSIONS: Prolonged combat-training not only induces the expected increases in stress, anxiety and depression, but also GI symptoms, pro-inflammatory immune activation and increased intestinal permeability. Identification of subgroups of individuals at high-risk of GI compromise and of long-term deleterious effects of operational stress as well as the development of protective measures will be the focus of future studies.

Combustion smoke-induced inflammation in the cerebellum and hippocampus of adult rats.

AIMS: The effect of combustion smoke inhalation on the respiratory system is widely reported but its effects on the central nervous system remain unclear. Here, we aimed to determine the effects of smoke inhalation on the cerebellum and hippocampus which are areas vulnerable to hypoxia injury. METHODS: Adult male Sprague-Dawley rats were subjected to combustion smoke inhalation and sacrificed at 0.5, 3, 24 and 72 h after exposure. The cerebellum and hippocampus were subjected to Western analysis for VEGF, iNOS, eNOS, nNOS and AQP4 expression; ELISA analysis for cytokine and chemokine levels; and immunohistochemistry for GFAP/AQP4, RECA-1/RITC and TUNEL. Aminoguanidine (AG) was administered to determine the effects of iNOS after smoke inhalation. RESULTS: Both the cerebellum and hippocampus showed a significant increase in VEGF, iNOS, eNOS, nNOS and AQP4 expression with corresponding increases in inflammatory cytokines and chemokines and increased AQP4 expression and RITC permeability after smoke exposure. AG was able to decrease the expression of iNOS, followed by VEGF, eNOS, nNOS, RITC and AQP4 after smoke exposure. There was also a significant increase in TUNEL+ cells in the cerebellum and hippocampus which were not significantly reduced by AG. Beam walk test revealed immediate deficits after smoke inhalation which was attenuated with AG. CONCLUSION: The findings suggest that iNOS plays a major role in the central nervous system inflammatory pathophysiology after smoke inhalation exposure with concomitant increase in proinflammatory molecules, vascular permeability and oedema, for which the cerebellum appears to be more vulnerable to smoke exposure than the hippocampus.

General theory for the ferroelectric polarization induced by spin-spiral order.

The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained by any existing model of magnetic-order-driven ferroelectricity. We resolve this problem by developing a general theory for the ferroelectric polarization induced by spin-spiral order and then by evaluating the coefficients needed to specify the general theory on the basis of density functional calculations. Our theory correctly describes the ferroelectricity of triangular-lattice antiferromagnets driven by helical spin-spiral order and incorporates known models of magnetic-order-driven ferroelectricity as special cases.

Stem cell therapy for spinal cord injury.

Spinal cord injury (SCI) damages axons and disrupts myelination interrupting sensory and motor neuronal transmission to and from the brain. Patients suffering from SCI although continue to survive, are often left chronically disabled and with no promise of a cure. Advances in stem cell biology has opened up doors for the use of human embryonic, adult neural and induced pluripotent stem cell strategies for SCI. Despite great promise from animal research, clinical trials have been limited and the jury is still out on its safety and efficacy. This review discusses the advantages and disadvantages of the various stem cell types, barriers hindering translation from animal to humans, and the need for established guidelines for standardization of clinical trials ensuring subsequent implementation. Ultimately, unrealistic expectations of stem cell therapy (SCT) as the elixir for SCI should be managed. The success of SCT for SCI lies in the network of research scientists, medical professionals and patients working cooperatively to build up a knowledge-intensive platform for a comprehensive risk-benefit assessment of SCT for SCI.

Massive occult haemoperitoneum following spontaneous rupture of duodenal gastrointestinal stromal tumour.

Gastrointestinal stromal tumours are an uncommon subset of mesenchymal tumour that can occur anywhere along the gastrointestinal tract. Diagnosis of gastrointestinal stromal tumours is often difficult, as presentation is variable. This case report identifies massive haemoperitoneum as an initial finding, which is an unusual mode of presentation in gastrointestinal stromal tumours.

Normal developmental changes in inferior frontal gray matter are associated with improvement in phonological processing: a longitudinal MRI analysis.

This study asked whether previously identified developmental changes in the gray matter of the left inferior frontal gyrus are associated with maturation of a linguistic skill. To test this hypothesis, we examined whether thickening of this region was correlated with developmental improvements in phonological processing but not hand motor skills in a unique longitudinal data set of 45 normally developing children (between ages 5 and 11 years) studied over a 2-year interval. We analyzed structural magnetic resonance imaging data using cortical pattern matching methods and correlated within-individual changes in cortical thickness with 2 neurocognitive scores. As predicted, gray matter thickening in the left inferior frontal cortex was associated with improving phonological processing scores but not with improving hand motor skills. By contrast, motor skill improvement was associated with thinning in the hand region of the left motor cortex, and cortical change in this region was not associated with phonological processing. This study illustrates a specific correspondence between regional gray matter thickness change and language skill change in normally developing children.

Transport of living cells with magnetically assembled nanowires.

We present a technique of transporting and positioning living cells internalized by nickel (Ni) nanowires guided by magnetic field. Nanoscale magnetic nanowires are internalized by the Rat Neuroblastoma (ATCC number CRL-2754) and the cells are transported and positioned by magnetic fields from the magnetic material-coated electrodes. This technique may enable the interfacing between neurons and electronic devices to empower investigations pertaining to non-invasive neuron probing as well as nanofabricated neural pharmacological technologies.

Scale-up and cost evaluation of a foamed emulsion bioreactor.

In the present paper, the potential of the foamed emulsion bioreactor (FEBR), a novel biological reactor for air pollution control was evaluated. Experimental data obtained on a laboratory-scale prototype were used to scale-up the process for a hypothetical case consisting of a contaminated air flow rate of 10,000 m(3) h(-1), a toluene inlet concentration of 1 g m(-3) and minimum required treatment efficiency of 92%. Reactor design and operating issues for the full-scale FEBR were identified. They included the requirement for stable foam generation with appropriate air distributors, and recycling of the auxiliary organic phase, surfactants and cells from the discharge of the reactor. The capital and operating costs for the concept full-scale FEBR were evaluated and compared to those of competing technologies, namely biofiltration, biotrickling filtration and catalytic and thermal oxidation. All three biological techniques had significantly lower capital and operating costs. Among the biological techniques, the FEBR had the lowest estimated capital cost since its greater effectiveness allowed a smaller reactor to meet the treatment objectives. The operating costs for the FEBR were higher than those of biofilters and biotrickling filters because of the requirements for nutrients and auxiliary chemicals. Overall, the results highlight that biotreatment is much more cost effective than thermal and catalytic oxidation. They further suggest that the FEBR may an interesting alternative to biofilters and biotrickling filters where the available space for air pollution control equipment is limited.

Peritonitis in childhood: clinical relevance of cytokines in the peritoneal exudate.

BACKGROUND: The aim of the study was to assess pro-inflammatory cytokine (tumor necrosis factor alpha [TNF-alpha], interleukin 6 [IL-6]) and anti-inflammatory cytokine (interleukin 10 [IL-10]) responses in children with peritonitis secondary to hollow viscus perforation, and to evaluate the influence of peritoneal microbial status on cytokine expression and morbidity. METHODS: The peritoneal fluid of 13 children with perforated appendicitis was examined with qualitative analysis of bacteria, and measurement of cytokine levels, which were compared to cytokine plasma levels, over a five-day period following operation. RESULTS: All fluid specimens showed permanently elevated levels of TNF-alpha and IL-10. IL-6 tended to decrease to normal levels by the 5th postoperative day. Peritoneal exudate levels of TNF-alpha and IL-10 were more than 100 - 1000 times greater than those in plasma. The most common bacterial species isolated in the peritoneal fluid was Escherichia coli. Despite persisting high cytokine concentrations and bacterial load of the peritoneal cavity for 5 days postoperatively, the children recovered uneventfully and the systemic signs of infection disappeared rapidly. CONCLUSION: Neither the bacterial nor the pro-inflammatory cytokine load of the peritoneal cavity proved to be associated with the clinical course. We hypothesize that in peritonitis in childhood a significant and clinically relevant cytokine-mediated inflammatory response is compartmentalized in the peritoneal cavity. Therefore adjuvant surgical measures in addition to appendectomy and intraoperative debridement seem not to be necessary, at least for peritonitis due to perforated appendicitis in children.