Integrins are required for synchronous ommatidial rotation in the Drosophila eye linking planar cell polarity signalling to the extracellular matrix

Integrins mediate the anchorage between cells and their environment, the extracellular matrix (ECM), and form transmembrane links between the ECM and the cytoskeleton, a conserved feature throughout development and morphogenesis of epithelial organs. Here, we demonstrate that integrins and components of the ECM are required during the planar cell polarity (PCP) signalling-regulated cell movement of ommatidial rotation in the Drosophila eye. The loss-of-function mutations of integrins or ECM components cause defects in rotation, with mutant clusters rotating asynchronously compared to wild-type clusters. Initially, mutant clusters tend to rotate faster, and at later stages they fail to be synchronous with their neighbours, leading to aberrant rotation angles and resulting in a disorganized ommatidial arrangement in adult eyes. We further demonstrate that integrin localization changes dynamically during the rotation process. Our data suggest that core Frizzled/PCP factors, acting through RhoA and Rho kinase, regulate the function/activity of integrins and that integrins thus contribute to the complex interaction network of PCP signalling, cell adhesion and cytoskeletal elements required for a precise and synchronous 90° rotation movement.

Faecal microbiota transplantation for treatment of recurrent or refractory Clostridioides difficile infection in Hong Kong

INTRODUCTION

Clostridioides difficile infection (CDI) is a leading cause of healthcare-associated infection globally, causing significant morbidity and mortality. Faecal microbiota transplantation (FMT) has emerged as a promising option for recurrent and refractory CDI. This study aimed to assess the safety, efficacy, and feasibility of FMT for CDI in Hong Kong.

METHODS

We conducted a single-centre, retrospective study for all consecutive cases of recurrent or refractory CDI who underwent FMT from 2013 to 2018. Clinical demographics, outcome, and safety parameters were collected.

RESULTS

A total of 24 patients with recurrent or refractory CDI (median age 70 years, interquartile range=45.0-78.3 years; 67% male) were included. Over 80% had been recently hospitalised or were long-term care facility residents. Faecal microbiota transplantation was delivered by feeding tube in 11 (45.8%), oesophagogastroduodenoscopy in eight (33.3%), and colonoscopy in six (25%) of the patients. Resolution of diarrhoea without relapse within 8 weeks was achieved in 21 out of 24 patients (87.5%) after FMT. No deaths occurred within 30 days. The FMT was well tolerated and no serious adverse events attributable to FMT were reported.

CONCLUSION

Our results confirm that FMT is a safe, efficacious, and feasible intervention for patients with refractory or recurrent CDI in Hong Kong. Given the increasing disease burden and the lack of effective alternatives in Hong Kong for difficult-to-treat cases of CDI, we recommend that a territory-wide FMT service be established to address increasing demand for this treatment.

Sample-to-answer on molecular diagnosis of bacterial infection using integrated lab--on--a--disc

Sepsis by bacterial infection causes high mortality in patients in intensive care unit (ICU). Rapid identification of bacterial infection is essential to ensure early appropriate administration of antibiotics to save lives of patients, yet the present benchtop molecular diagnosis is time-consuming and labor-intensive, which limits the treatment efficiency especially when the number of samples to be tested is extensive. Therefore, we hereby report a microfluidic platform lab-on-a-disc (LOAD) to provide a sample-to-answer solution. Our LOAD customized design of microfluidic channels allows automation to mimic sequential analytical steps in benchtop environment. It relies on a simple but controllable centrifugation force for the actuation of samples and reagents. Our LOAD system performs three major functions, namely DNA extraction, isothermal DNA amplification and real-time signal detection, in a predefined sequence. The disc is self-contained for conducting sample heating with chemical lysis buffer and silica microbeads are employed for DNA extraction from clinical specimens. Molecular diagnosis of specific target bacteria DNA sequences is then performed using a real-time loop-mediated isothermal amplification (RT-LAMP) with SYTO-9 as the signal reporter. Our LOAD system capable of bacterial identification of Mycobacterium tuberculosis (TB) and Acinetobacter baumanii (Ab) with the detection limits 103cfu/mL TB in sputum and 102cfu/mL Ab in blood within 2h after sample loading. The reported LOAD based on an integrated approach should address the growing needs for rapid point-of-care medical diagnosis in ICU.

The Drosophila selectin furrowed mediates intercellular planar cell polarity interactions via frizzled stabilization

Establishment of planar cell polarity (PCP) in a tissue requires coordination of directional signals from cell to cell. It is thought that this is mediated by the core PCP factors, which include cell-adhesion molecules. Here, we demonstrate that furrowed, the Drosophila selectin, is required for PCP generation. Disruption of PCP in furrowed-deficient flies results from a primary defect in Fz levels and cell adhesion. Furrowed localizes at or near apical junctions, largely colocalizing with Frizzled and Flamingo (Fmi). It physically interacts with and stabilizes Frizzled, and it mediates intercellular Frizzled-Van Gogh (Vang)/Strabismus interactions, similarly to Fmi. Furrowed does so through a homophilic cell-adhesion role that is distinct from its known carbohydrate-binding function described during vertebrate blood-cell/endothelial cell interactions. Importantly, the carbohydrate function is dispensable for PCP establishment. In vivo studies suggest that Furrowed functions partially redundantly with Fmi, mediating intercellular Frizzled-Vang interactions between neighboring cells.

Impairment of ubiquitylation by mutation in Drosophila E1 promotes both cell-autonomous and non-cell-autonomous Ras-ERK activation in vivo

Ras signaling can promote proliferation, cell survival and differentiation. Mutations in components of the Ras pathway are found in many solid tumors and are associated with developmental disorders. We demonstrate here that Drosophila tissues containing hypomorphic mutations in E1, the most upstream enzyme in the ubiquitin pathway, display cell-autonomous upregulation of Ras-ERK activity and Ras-dependent ectopic proliferation. Ubiquitylation is widely accepted to regulate receptor tyrosine kinase (RTK) endocytosis upstream of Ras. However, although the ectopic proliferation of E1 hypomorphs is dramatically suppressed by removing one copy of Ras, removal of the more upstream components Egfr, Grb2 or sos shows no suppression. Thus, decreased ubiquitylation may lead to growth-relevant Ras-ERK activation by failing to regulate a step downstream of RTK endocytosis. We further demonstrate that Drosophila Ras is ubiquitylated. Our findings suggest that Ras ubiquitylation restricts growth and proliferation in vivo. We also report our intriguing observation that complete inactivation of E1 causes non-autonomous activation of Ras-ERK in adjacent tissue, mimicking oncogenic Ras overexpression. We demonstrate that maintaining sufficient E1 function is required both cell autonomously and non-cell autonomously to prevent inappropriate Ras-ERK-dependent growth and proliferation in vivo and may implicate loss of Ras ubiquitylation in developmental disorders and cancer.

Rapid identification of medically important Candida to species level by polymerase chain reaction and single-strand conformational polymorphism

Invasive fungal disease has taken a great toll on immunocompromised patients. With the emergence of fluconazole and amphotericin B resistance, the rapid identification of fungi to species level is of clinical relevance in guiding appropriate antifungal therapy. Among these opportunistic fungi, Candida species are the most commonly encountered. We had developed a molecular method utilizing single-strand conformational polymorphism (SSCP) to delineate different patterns on a 260-bp amplicon from the 28S rRNA gene from six medically important Candida species. The SSCP banding patterns obtained from a total of 52 isolates were sufficiently unique to allow distinction between the species, thus indicated a high level of specificity. This method of PCR-SSCP can provide a simple and specific method for the rapid identification of medically important Candida to species level.

Transdermal fentanyl for postoperative pain management in patients recovering from abdominal gynecologic surgery

The current placebo-controlled double-blinded study was undertaken to assess the safety and efficacy, as well as the potential clinical role, of the transdermal therapeutic system (TTS) of fentanyl delivery in the postoperative setting. TTS patches releasing 25 micrograms.h-1 or 50 micrograms.h-1 or placebo were applied to 95 women 1 h before abdominal gynecologic surgery during general anesthesia. Postoperatively, patients self-administered intravenous morphine as required using patient-controlled analgesia with a 1-mg incremental dose and a 6-min lockout interval. Each was assessed upon admission to the postanesthesia care unit and at intervals over the following 72 h with respect to vital signs, visual analogue scale pain and satisfaction scores, side effects, and cumulative morphine use. Data were analyzed using analysis of variance, Kruskal-Wallis, and chi-square. P less than 0.05 was considered significant. There were no demographic differences among groups. Beginning 32 h after TTS application, a statistically significant morphine-sparing effect was seen with the 50 micrograms.h-1 patch. There were no significant differences among groups with regard to visual analogue scale pain scores at rest, patient satisfaction, or the incidence of side effects; a significant reduction in pain upon movement was noted at 24 h in patients treated with TTS 50 micrograms.h-1. This finding constituted the only benefit noted with this form of analgesic therapy in the present investigation.

Aortic valve systolic flutter as a screening test for severe aortic stenosis

Previous efforts using M-mode echocardiography or 2-dimensional (2-D) echocardiography have not consistently separated patients with and without significant aortic stenosis (AS). We postulated that an aortic valve sufficiently pliant to produce systolic flutter on M-mode echocardiography could exclude significant AS and reviewed the M-mode echocardiograms of 50 consecutive patients (mean age 59 years) catheterized for presumed AS; 2-D echocardiography was also performed in 18 of 50 patients (36%). In 40 of 50 patients (80%) the aortic valve cusps were easily identified on M-mode echocardiography: 19 of 40 (48%) had systolic flutter with a mean aortic valve gradient of 4 +/- 8 mm Hg (mean +/- standard deviation [SD]) and an aortic valve area of 2.8 +/- 0.4 cm2; 21 of 40 (52%) had no systolic flutter with a mean aortic valve gradient of 55 +/- 19 mm Hg and an aortic valve area of 0.7 +/- 0.3 cm2. In the 10 of 50 patients (20%) in whom aortic valve cusps were not clearly identified, the mean aortic valve gradient was 50 +/- 24 mm Hg and the aortic valve area 0.8 +/- 0.4 cm2. Systolic flutter was not seen with an aortic valve gradient greater than 30 mm Hg or an aortic valve area less than 1 cm2. Aortic valve systolic opening by M-mode echocardiography or 2-D echocardiography did not accurately predict the severity of AS. Thus, aortic valve systolic flutter seen on M-mode echocardiography is strong evidence against significant AS, but the absence of systolic flutter does not allow reliable prediction of the severity of AS. The finding of systolic flutter by M-mode echocardiography may be a useful screening test in patients presumed to have AS.

Treating adolescent obesity: a pilot project in a school

A weight control program for junior high school students was developed to change eating, exercise and habit patterns. The course included dietary management, physical activity and behavior modification techniques. Classes were structured to emphasize peer group involvement and daily practical application. The curriculum was compiled in a book for educational personnel. The program was tested as a pilot project with a selected group of eighth grade obese adolescent girls and a comparison group. Immediately after the course, the subjects' percent of overweight had decreased; at a subsequent eight-month follow-up, additional losses were noted. The percent of overweight of the girls in the comparison group remained relatively unchanged. While the program was successful with this particular group of students, several key questions, requiring further study, were defined.

Intensive care in adolescent pregnancy

Adolescent pregnancy has long been considered high risk perinatally. It is also a symptom of social disorder. Older studies provided ominous portents of increased risk of toxemia, prematurity, anemia, cephalopelvic disproportion, and perinatal wastage. Studies during the past decade have shown more encouraging data, especially when representing a concerted effort toward this age group. The first 2 years of an intensive and individual approach to gravidas under age 17 are discussed. A total of 135 young women were studied and compared with 100 controls of similar age, treated routinely, and with 100 women of more nearly ideal childbearing age. Perinatal and social data are shown. The implications of the data are discussed in light of other studies. Few, if any, medical differences between the two groups of adolescents and the older women are noted. More important are the social and emotional factors in determining future difficulties.