Gender Differences in Smoking Attitude among Saudi Medical Students.

BACKGROUND: Smoking is a growing public health problem throughout the world. However, the attitude of males and females toward smoking may differ. Therefore, this study examines gender differences in smoking behavior and attitude among Saudi medical students. METHODS: From January 2020 to August 2020, a snowball cross-sectional online survey was conducted in five major regions of Saudi Arabia. Medical students (18 years or older) were invited to respond to the questionnaire. RESULTS: Out of the 421 respondents, 255 (60.6%) were female, 243 (57.7%) were between 18 and-24-year-old, and 164 (39%) were from the Eastern Province. The overall prevalence of smoking was 25.4% and was higher among males than females [(44% and 13.3%, respectively), P < 0.001]. However, there was no significant difference in the mean score of the overall attitude towards smoking between males and females [(3.02±0.44 and 3.00±0.34), respectively, P=0.64]. However, more female students believed e-cigarettes were harmful to health than male students [(4.19±1.04 and 4.45±0.9), respectively, P=0.002]. CONCLUSION: The study showed that male students smoke more than female students, and there were no significant differences in the overall attitudes score towards smoking. Therefore, campaigns are needed to decrease smoking rate, especially among male students.

Preclinical Evaluation of the Safety and Efficacy of Cryopreserved Bone Marrow Mesenchymal Stromal Cells for Corneal Repair.

Purpose: Mesenchymal stromal cells (MSCs) have been shown to enhance tissue repair as a cell-based therapy. In preparation for a phase I clinical study, we evaluated the safety, dosing, and efficacy of bone marrow-derived MSCs after subconjunctival injection in preclinical animal models of mice, rats, and rabbits. Methods: Human bone marrow-derived MSCs were expanded to passage 4 and cryopreserved. Viability of MSCs after thawing and injection through small-gauge needles was evaluated by vital dye staining. The in vivo safety of human and rabbit MSCs was studied by subconjunctivally injecting MSCs in rabbits with follow-up to 90 days. The potency of MSCs on accelerating wound healing was evaluated in vitro using a scratch assay and in vivo using 2-mm corneal epithelial debridement wounds in mice. Human MSCs were tracked after subconjunctival injection in rat and rabbit eyes. Results: The viability of MSCs after thawing and immediate injection through 27- and 30-gauge needles was 93.1% ± 2.1% and 94.9% ± 1.3%, respectively. Rabbit eyes demonstrated mild self-limiting conjunctival inflammation at the site of injection with human but not rabbit MSCs. In scratch assay, the mean wound healing area was 93.5% ± 12.1% in epithelial cells co-cultured with MSCs compared with 40.8% ± 23.1% in controls. At 24 hours after wounding, all MSC-injected murine eyes had 100% corneal wound closure compared with 79.9% ± 5.5% in controls. Human MSCs were detectable in the subconjunctival area and peripheral cornea at 14 days after injection. Conclusions: Subconjunctival administration of MSCs is safe and effective in promoting corneal epithelial wound healing in animal models. Translational Relevance: These results provide preclinical data to support a phase I clinical study.

Novel exomic rare variants associated with venous thrombosis.

Exomic rare variant polymorphisms (c. 300 000) were analysed in the Scripps Venous Thrombosis (VTE) registry (subjects aged <55 years). Besides coagulation factor V (F5) single nucleotide polymorphisms (SNPs), family with sequence similarity 134, member B (FAM134B; rs78314670, Arg127Cys) and myosin heavy chain 8 (MYH8; rs111567318, Glu1838Ala) SNPs were associated with recurrent VTE (n = 34 cases) (false discovery rate-adjusted P < 0·05). FAM134B (rs78314670) was associated with low plasma levels of anticoagulant glucosylceramide. Analysis of 50 chr17p13.1 MYH rare SNPs (clustered skeletal myosin heavy chain genes) using collapsing methods was associated with recurrent VTE (P = 2·70 ×10-16 ). When intravenously injected, skeletal muscle myosin was pro-coagulant in a haemophilia mouse tail bleeding model. Thus, FAM134B and MYH genetic variants are plausibly linked to VTE risk.

µECoG Recordings Through a Thinned Skull.

The studies described in this paper for the first time characterize the acute and chronic performance of optically transparent thin-film micro-electrocorticography (µECoG) grids implanted on a thinned skull as both an electrophysiological complement to existing thinned skull preparation for optical recordings/manipulations, and a less invasive alternative to epidural or subdurally placed µECoG arrays. In a longitudinal chronic study, µECoG grids placed on top of a thinned skull maintain impedances comparable to epidurally placed µECoG grids that are stable for periods of at least 1 month. Optogenetic activation of cortex is also reliably demonstrated through the optically transparent µECoG grids acutely placed on the thinned skull. Finally, spatially distinct electrophysiological recordings were evident on µECoG electrodes placed on a thinned skull separated by 500-750 µm, as assessed by stimulation evoked responses using optogenetic activation of cortex as well as invasive and epidermal stimulation of the sciatic and median nerve at chronic time points. Neural signals were collected through a thinned skull in mice and rats, demonstrating potential utility in neuroscience research applications such as in vivo imaging and optogenetics.

Molecular interaction site on procoagulant myosin for factor Xa-dependent prothrombin activation.

Skeletal muscle myosin has potent procoagulant activity that is based on its ability to enhance thrombin generation due to binding coagulation factors Xa and Va and accelerating prothrombin activation. A well-studied myosin inhibitor that binds to myosin's neck region inhibits myosin-dependent prothrombin activation. Hence, to identify a potential binding site(s) on skeletal muscle myosin for factor Xa, 19 peptides (25-40 residues) representing the neck region, which consists of a regulatory light chain, an essential light chain, and a heavy chain (HC), were screened for inhibition of myosin-supported prothrombin activation. Peptide HC796-835 comprising residues 796-835 of the heavy chain strongly inhibited myosin-enhanced prothrombin activation by factors Xa and Va (50% inhibition at 1.2 µm), but it did not inhibit phospholipid vesicle-enhanced prothrombin activation. Peptide inhibition studies also implicated several myosin light chain sequences located near HC796-835 as potential procoagulant sites. A peptide comprising HC796-835's C-terminal half, but not a peptide comprising its N-terminal half, inhibited myosin-enhanced prothrombin activation (50% inhibition at 1.2 µm). This inhibitory peptide (HC816-837) did not inhibit phospholipid-enhanced prothrombin activation, indicating its specificity for inhibition of myosin-dependent procoagulant mechanisms. Binding studies showed that purified factor Xa was bound to immobilized peptides HC796-835 and HC816-837 with apparent Kd values of 0.78 and 1.3 µm, respectively. In summary, these studies imply that HC residues 816-835 in the neck region of the skeletal muscle myosin directly bind factor Xa and, with contributions from light chain residues in this neck region, contribute to provision of myosin's procoagulant surface.

Intracameral Air and Fibrin Glue for the Management of Late Bleb Leak following Glaucoma Surgery.

BACKGROUND AND OBJECTIVES: To report a case of delayed-onset bleb-associated endophthalmitis (BAE) with bleb leak successfully managed with pars plana vitrectomy, intravitreal antibiotics, intracameral air, and fibrin glue. PATIENT AND METHODS: A 66-year-old pseudophakic female presented with BAE and bleb leak. A 25-gauge pars plana vitrectomy, cultures, and intravitreal antibiotics and steroid injections were performed. The infusion was switched to air filling the anterior chamber and bleb with air. Fibrin glue (Tisseel®) was applied over the leaking bleb. RESULTS: BAE and bleb leak resolved with return of visual acuity to 20/25 and a functioning bleb with no recurrence of bleb leak after 1 year of follow-up. CONCLUSION: The combination of intracameral air and fibrin glue may have a role in the management of bleb leaks.

Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications.

Neural micro-electrode arrays that are transparent over a broad wavelength spectrum from ultraviolet to infrared could allow for simultaneous electrophysiology and optical imaging, as well as optogenetic modulation of the underlying brain tissue. The long-term biocompatibility and reliability of neural micro-electrodes also require their mechanical flexibility and compliance with soft tissues. Here we present a graphene-based, carbon-layered electrode array (CLEAR) device, which can be implanted on the brain surface in rodents for high-resolution neurophysiological recording. We characterize optical transparency of the device at >90% transmission over the ultraviolet to infrared spectrum and demonstrate its utility through optical interface experiments that use this broad spectrum transparency. These include optogenetic activation of focal cortical areas directly beneath electrodes, in vivo imaging of the cortical vasculature via fluorescence microscopy and 3D optical coherence tomography. This study demonstrates an array of interfacing abilities of the CLEAR device and its utility for neural applications.

A chronic window imaging device for the investigation of in vivo peripheral nerves.

Chronic imaging of the peripheral nervous system with contemporary techniques requires repetitive surgical procedures to reopen an area of interest in order to see underlying biological processes over time. The recurrence of surgical openings on an animal increases trauma, stress, and risk of infection. Such effects can greatly lessen the physiological relevance of any data recorded in this manner. In order to bypass repetitive surgery, a Peripheral Nerve Window (PNW) device has been created for chronic in vivo imaging purposes. Intravital imaging window devices have been used previously to image parts of the rodent model such as the brain, spinal cord, and mammary tissue, but currently have not been used in the peripheral nervous system because of lack of bone anchoring and access to deep nerve tissue. We demonstrate a novel surgical technique in a rat which transposes the sciatic nerve above the surrounding muscle tissue allowing the PNW access to an 8mm section of the nerve. Subsequent days of observation revealed increased vasculature development primarily around the nerve, showing that this preparation can be used to image nerve tissue and surrounding vasculature for up to one week post-implantation.