Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

The effect of incorrect scanning distance on boundary detection errors and macular thickness measurements by spectral domain optical coherence tomography: a cross sectional study

BACKGROUND: To investigate the influence of scan distance on retinal boundary detection errors (RBDEs) and retinal thickness measurements by spectral domain optical coherence tomography (SD-OCT). METHODS: 10 eyes of healthy subjects, 10 eyes with diabetic macular edema (DME) and 10 eyes with neovascular age-related macular degeneration (AMD) were examined with RTVue SD-OCT. The MM5 protocol was used in two consecutive sessions to scan the macula. For the first session, the device was set 3.5 cm from the eye in order to obtain detectable signal with low fundus image quality (suboptimal setting) while in the second session a distance of 2.5 cm was set with a good quality fundus image. The signal strength (SSI) value was recorded. The score for retinal boundary detection errors (RBDE) was calculated for ten scans of each examination. RBDE scores were recorded for the whole scan and also for the peripheral 1.0 mm region. RBDE scores, regional retinal thickness values and SSI values between the two sessions were compared. The correlation between SSI and the number of RBDEs was also examined. RESULTS: The SSI was significantly lower with suboptimal settings compared to optimal settings (63.9+/-12.0 vs. 68.3+/-12.2, respectively, p = 0.001) and the number of RBDEs was significantly higher with suboptimal settings in the "all-eyes" group along with the group of healthy subjects and eyes with DME (9.1+/-6.5 vs. 6.8+/-6.3, p = 0.007; 4.4+/-2.6 vs. 2.5+/-1.6, p = 0.035 and 9.7+/-3.3 vs. 5.1+/-3.7, p = 0.008, respectively). For these groups, significant negative correlation was found between the SSI and the number of RBDEs. In the AMD group, the number of RBDEs was markedly higher compared to the other groups and there was no difference in RBDEs between optimal and suboptimal settings with the errors being independent of the SSI. There were significantly less peripheral RBDEs with optimal settings in the "all-eyes" group and the DME subgroup (2.7+/-2.6 vs. 4.2+/-2.8, p = 0.001 and 1.4+/-1.7 vs. 4.1+/-2.2, p = 0.007, respectively). Retinal thickness in the two settings was significantly different only in the outer-superior region in DME. CONCLUSIONS: Optimal distance settings improve SD-OCT SSI with a decrease in RBDEs while retinal thickness measurements are independent of scanning distance

Complex folding and misfolding effects of deer-specific amino acid substitutions in the β2-α2 loop of murine prion protein

The β2–α2 loop of PrPC is a key modulator of disease-associated prion protein misfolding. Amino acids that differentiate mouse (Ser169, Asn173) and deer (Asn169, Thr173) PrPC appear to confer dramatically different structural properties in this region and it has been suggested that amino acid sequences associated with structural rigidity of the loop also confer susceptibility to prion disease. Using mouse recombinant PrP, we show that mutating residue 173 from Asn to Thr alters protein stability and misfolding only subtly, whilst changing Ser to Asn at codon 169 causes instability in the protein, promotes oligomer formation and dramatically potentiates fibril formation. The doubly mutated protein exhibits more complex folding and misfolding behaviour than either single mutant, suggestive of differential effects of the β2–α2 loop sequence on both protein stability and on specific misfolding pathways. Molecular dynamics simulation of protein structure suggests a key role for the solvent accessibility of Tyr168 in promoting molecular interactions that may lead to prion protein misfolding. Thus, we conclude that ‘rigidity’ in the β2–α2 loop region of the normal conformer of PrP has less effect on misfolding than other sequence-related effects in this region

Effect of promoter architecture on the cell-to-cell variability in gene expression

According to recent experimental evidence, the architecture of a promoter, defined as the number, strength and regulatory role of the operators that control the promoter, plays a major role in determining the level of cell-to-cell variability in gene expression. These quantitative experiments call for a corresponding modeling effort that addresses the question of how changes in promoter architecture affect noise in gene expression in a systematic rather than case-by-case fashion. In this article, we make such a systematic investigation, based on a simple microscopic model of gene regulation that incorporates stochastic effects. In particular, we show how operator strength and operator multiplicity affect this variability. We examine different modes of transcription factor binding to complex promoters (cooperative, independent, simultaneous) and how each of these affects the level of variability in transcription product from cell-to-cell. We propose that direct comparison between in vivo single-cell experiments and theoretical predictions for the moments of the probability distribution of mRNA number per cell can discriminate between different kinetic models of gene regulation.Comment: 35 pages, 6 figures, Submitte

Clinical impact of a targeted next-generation sequencing gene panel for autoinflammation and vasculitis.

BACKGROUND: Monogenic autoinflammatory diseases (AID) are a rapidly expanding group of genetically diverse but phenotypically overlapping systemic inflammatory disorders associated with dysregulated innate immunity. They cause significant morbidity, mortality and economic burden. Here, we aimed to develop and evaluate the clinical impact of a NGS targeted gene panel, the "Vasculitis and Inflammation Panel" (VIP) for AID and vasculitis. METHODS: The Agilent SureDesign tool was used to design 2 versions of VIP; VIP1 targeting 113 genes, and a later version, VIP2, targeting 166 genes. Captured and indexed libraries (QXT Target Enrichment System) prepared for 72 patients were sequenced as a multiplex of 16 samples on an Illumina MiSeq sequencer in 150bp paired-end mode. The cohort comprised 22 positive control DNA samples from patients with previously validated mutations in a variety of the genes; and 50 prospective samples from patients with suspected AID in whom previous Sanger based genetic screening had been non-diagnostic. RESULTS: VIP was sensitive and specific at detecting all the different types of known mutations in 22 positive controls, including gene deletion, small INDELS, and somatic mosaicism with allele fraction as low as 3%. Six/50 patients (12%) with unclassified AID had at least one class 5 (clearly pathogenic) variant; and 11/50 (22%) had at least one likely pathogenic variant (class 4). Overall, testing with VIP resulted in a firm or strongly suspected molecular diagnosis in 16/50 patients (32%). CONCLUSIONS: The high diagnostic yield and accuracy of this comprehensive targeted gene panel validate the use of broad NGS-based testing for patients with suspected AID

De Novo Truncating Mutations in WASF1 Cause Intellectual Disability with Seizures.

Next-generation sequencing has been invaluable in the elucidation of the genetic etiology of many subtypes of intellectual disability in recent years. Here, using exome sequencing and whole-genome sequencing, we identified three de novo truncating mutations in WAS protein family member 1 (WASF1) in five unrelated individuals with moderate to profound intellectual disability with autistic features and seizures. WASF1, also known as WAVE1, is part of the WAVE complex and acts as a mediator between Rac-GTPase and actin to induce actin polymerization. The three mutations connected by Matchmaker Exchange were c.1516C>T (p.Arg506Ter), which occurs in three unrelated individuals, c.1558C>T (p.Gln520Ter), and c.1482delinsGCCAGG (p.Ile494MetfsTer23). All three variants are predicted to partially or fully disrupt the C-terminal actin-binding WCA domain. Functional studies using fibroblast cells from two affected individuals with the c.1516C>T mutation showed a truncated WASF1 and a defect in actin remodeling. This study provides evidence that de novo heterozygous mutations in WASF1 cause a rare form of intellectual disability

Macular OCT inner retinal changes reflect CNS involvement in m.3243A>G disease

\ua9 Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.Background The m.3243A>G mitochondrial DNA variant is the most common cause of adult mitochondrial disease and is associated with a heterogeneous clinical phenotype. The retina and optic nerve are among the most metabolically active tissues, making them vulnerable to mitochondrial dysfunction. Optical coherence tomography (OCT) studies have demonstrated retinal nerve fibre layer (RNFL) thinning in mitochondrial and other neurodegenerative diseases. We investigated whether temporal RNFL thinning is associated with central nervous system (CNS) involvement in individuals with the m.3243A>G variant. Methods High-resolution OCT was used to assess peripapillary RNFL thickness and perform macular segmentation. Participants were categorised into normal RNFL (n=14) or temporal RNFL thinning (n=15) groups. Demographic data, mean-corrected m.3243A>G heteroplasmy, Newcastle Mitochondrial Disease Adult Scale (NMDAS) scaled scores and NMDAS neurological traits were compared. Results Temporal RNFL thinning was significantly associated with neurological features (Fisher’s exact test, p=0.027). In multivariable analysis, RNFL thinning and age were independent predictors of neurological involvement. Macular OCT revealed concomitant thinning of the ganglion cell-inner plexiform (GC-IPL) complex in the RNFL thinning group, with preservation of outer retinal layers, supporting primary retinal ganglion cell vulnerability. No significant associations were found between RNFL thinning and m.3243A>G heteroplasmy or NMDAS scaled scores. Conclusion Temporal RNFL thinning, accompanied by GC-IPL loss, is associated with neurological involvement in m.3243A>G-related mitochondrial disease, supporting its potential as a non-invasive biomarker of CNS dysfunction. Longitudinal studies are needed to determine whether these retinal changes are progressive and predictive of neurological decline

Jejunal perforation in gallstone ileus – a case series

<p>Abstract</p> <p>Introduction</p> <p>Gallstone ileus is an uncommon complication of cholelithiasis but an established cause of mechanical bowel obstruction in the elderly. Perforation of the small intestine proximal to the obstructing gallstone is rare, and only a handful of cases have been reported. We present two cases of perforation of the jejunum in gallstone ileus, and remarkably in one case, the gallstone ileus caused perforation of a jejunal diverticulum and is to the best of our knowledge the first such case to be described.</p> <p>Case presentations</p> <p><b>Case 1</b></p> <p>A 69 year old man presented with two days of vomiting and central abdominal pain. He underwent laparotomy for small bowel obstruction and was found to have a gallstone obstructing the mid-ileum. There was a 2 mm perforation in the anti-mesenteric border of the dilated proximal jejunum. The gallstone was removed and the perforated segment of jejunum was resected.</p> <p><b>Case 2</b></p> <p>A 68 year old man presented with a four day history of vomiting and central abdominal pain. Chest and abdominal radiography were unremarkable however a subsequent CT scan of the abdomen showed aerobilia. At laparotomy his distal ileum was found to be obstructed by an impacted gallstone and there was a perforated diverticulum on the mesenteric surface of the mid-jejunum. An enterolithotomy and resection of the perforated small bowel was performed.</p> <p>Conclusion</p> <p>Gallstone ileus remains a diagnostic challenge despite advances in imaging techniques, and pre-operative diagnosis is often delayed. Partly due to the elderly population it affects, gallstone ileus continues to have both high morbidity and mortality rates. On reviewing the literature, the most appropriate surgical intervention remains unclear.</p> <p>Jejunal perforation in gallstone ileus is extremely rare. The cases described illustrate two quite different causes of perforation complicating gallstone ileus. In the first case, perforation was probably due to pressure necrosis caused by the gallstone. The second case was complicated by the presence of a perforated jejunal diverticulum, which was likely to have been secondary to the increased intra-luminal pressure proximal to the obstructing gallstone.</p> <p>These cases should raise awareness of the complications associated with both gallstone ileus, and small bowel diverticula.</p

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Pramipexole augmentation for the acute phase of treatment-resistant, unipolar depression: a placebo-controlled, double-blind, randomised trial in the UK

\ua9 2025 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: About 30% of patients with depression treated with antidepressant medication do not respond sufficiently to the first agents used. Pramipexole might usefully augment antidepressant medication in such cases of treatment-resistant depression, but data on its effects and tolerability are scarce. We aimed to assess the efficacy and tolerability of pramipexole augmentation of ongoing antidepressant treatment, over 48 weeks, in patients with treatment-resistant depression. Methods: We did a multicentre, double-blind, placebo-controlled randomised trial in which adults with resistant major depressive disorder were randomly assigned (1:1; using an online randomisation system) to 48 weeks of pramipexole (titrated to 2\ub75 mg) or placebo added to their ongoing antidepressant medication. The study was conducted in nine National Health Service Trusts in England. Participants, investigators, and researchers involved in recruitment and assessment were masked to group allocation, and the central pharmacy team dispensing the medication was not masked. The primary outcome was change from baseline to week 12 in the total score of the 16-item Quick Inventory of Depressive Symptomology self-report version (QIDS-SR16). The primary analysis was performed on the intention-to-treat population that included all eligible, randomly assigned participants. People with lived experience were involved in the design, oversight, and interpretation of the study. The trial was registered with ISCTRN (ISRCTN84666271) and EudraCT (2019-001023-13) and is complete. Findings: Between Feb 16 and May 29, 2024, 217 participants attended a screening visit, of whom 66 were excluded due to ineligibility. 151 participants were randomly assigned (75 to the pramipexole group and 75 to the placebo group, after one participant was found to be ineligible after randomisation). 84 (56%) participants were female and 66 (44%) were male and the mean age of participants was 44\ub79 years (SD 14\ub70). Ethnicity data were not available. The mean QIDS-SR16 total score at baseline was 16\ub74 (SD 3\ub74) in the pramipexole group and 16\ub72 (3\ub75) in the placebo group. The mean dose of pramipexole received at week 12 was 2\ub73 mg (SD 0\ub745). Adjusted mean decrease from baseline to week 12 of the QIDS-SR16 total score was 6\ub74 (SD 4\ub79) for the pramipexole group and 2\ub74 (4\ub70) for the placebo group; the mean difference between groups was −3\ub791 (95% CI −5\ub737 to −2\ub745; p&lt;0\ub70001). Termination of trial treatment due to adverse events was more frequent in the pramipexole group (15 participants [20%]) than in the placebo group (four participants [5%]), with reported adverse events consistent with known side-effects of pramipexole, in particular nausea, headache, and sleep disturbance or somnolence. Interpretation: In this trial involving participants with treatment-resistant depression, pramipexole augmentation of antidepressant treatment, at a target dose of 2\ub75 mg, demonstrated a reduction in symptoms relative to placebo at 12 weeks but was associated with some adverse effects. These results suggest that pramipexole is a clinically effective option for reducing symptoms in patients with treatment-resistant depression. Future trials directly comparing pramipexole with existing treatments for this disorder are needed. Funding: National Institute of Health and Care Research, Efficacy and Mechanism Evaluation Programme