Structural organisation of collagen in the corneas of primates and other mammals and the stromal changes associated with the disease keratoconus

X-ray diffraction was used to determine the ultrastructural arrangement of collagen in the normal human, monkey and bovine cornea. Using the same technique, the ultrastructural organisation of collagen in human keratoconus corneal buttons and in the corneas of mice with a murine specific keratopathy (SKC), in which the males develop a cone shaped cornea, was also examined. Collagen fibrils were found to be most closely packed in the prepupillary region of the normal human cornea, suggesting an optimisation of tissue strength and transparency in the main optical zone. In humans and marmoset monkeys, fibril size and interfibrillar spacing increased rapidly at the limbus to provide additional tensile strength at the point where the cornea meets the less curved sclera. A difference in the preferred orientation of collagen fibrils was observed between human and bovine corneas. Throughout the human corneal stroma, (and predominantly in the posterior stroma), collagen fibrils are preferentially aligned in the superior-inferior and nasal-temporal directions this alignment coincides with the insertion points of the rectus muscles. The proportion of aligned collagen mass (relative to the total collagen mass), which increases in all four quadrants of the peripheral human cornea, is highest in the superior-nasal and inferior-temporal regions, revealing a symmetry between the left and right cornea in terms of collagen mass distribution. Abnormalities in collagen orientation and mass distribution were seen in the majority of keratoconus corneal buttons examined. A relationship between the size and shape of the cone and the extent of the structural alterations was seen in some cases however a large variation existed between corneas. These results are consistent with a theoretical mechanism of keratoconus progression which involves enzyme action and inter-fibrillar and inter-lamellar slippage. Examination of the structural organisation of collagen in SKC mice corneas, revealed the strain to be an unsuitable model for studying human keratoconus.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

From Placement to Practice: Factors Affecting the Classroom ICT Integration of Pre-Service Teachers

Technological progress has resulted in unprecedented access to technology in education. While this removes the age-old issue of information and communications technology (ICT) availability for pre-service teachers, it does not remove the need to meaningfully integrate technology into their practice. Three areas of influence significantly impact the self-efficacy of pre-service teachers and, therefore, their ability to effectively use technology. The first, initial teacher education, should provide technological, pedagogical, and content knowledge (TPACK) initiatives to prepare trainees for practice, alongside mentors who are themselves competent in ICT integration. The second, schools and school communities, must provide relevant professional development around ICT use alongside a positive and open-minded culture around ICT use in the school, as well as addressing issues of access for students in lower socioeconomic areas. Finally, the pre-service teacher themselves must maintain an open mind and a constructivist pedagogical perspective to increase their own self-efficacy and successfully integrate technology into their future practice

Quality care, public perception and quick-fix service management: a Delphi study on stressors of hospital doctors in Ireland.

OBJECTIVES: To identify and rank the most significant workplace stressors to which consultants and trainees are exposed within the publicly funded health sector in Ireland. DESIGN: Following a preliminary semistructured telephone interview, a Delphi technique with 3 rounds of reiterative questionnaires was used to obtain consensus. Conducted in Spring 2014, doctors were purposively selected by their college faculty or specialty training body. SETTING: Consultants and higher specialist trainees who were engaged at a collegiate level with their faculty or professional training body. All were employed in the Irish publicly funded health sector by the Health Services Executive. PARTICIPANTS: 49 doctors: 30 consultants (13 male, 17 female) and 19 trainees (7 male, 12 female). Consultants and trainees were from a wide range of hospital specialties including anaesthetics, radiology and psychiatry. RESULTS: Consultants are most concerned with the quality of healthcare management and its impact on service. They are also concerned about the quality of care they provide. They feel undervalued within the negative sociocultural environment that they work. Trainees also feel undervalued with an uncertain future and they also perceive their sociocultural environment as negative. They echo concerns regarding the quality of care they provide. They struggle with the interface between career demands and personal life. CONCLUSIONS: This Delphi study sought to explore the working life of doctors in Irish hospitals at a time when resources are scarce. It identified both common and distinct concerns regarding sources of stress for 2 groups of doctors. Its identification of key stressors should guide managers and clinicians towards solutions for improving the quality of patient care and the health of care providers

Structural organisation of collagen in the corneas of primates and other mammals and the stromal changes associated with the disease keratoconus

X-ray diffraction was used to determine the ultrastructural arrangement of collagen in the normal human, monkey and bovine cornea. Using the same technique, the ultrastructural organisation of collagen in human keratoconus corneal buttons and in the corneas of mice with a murine specific keratopathy (SKC), in which the males develop a cone shaped cornea, was also examined. Collagen fibrils were found to be most closely packed in the prepupillary region of the normal human cornea, suggesting an optimisation of tissue strength and transparency in the main optical zone. In humans and marmoset monkeys, fibril size and interfibrillar spacing increased rapidly at the limbus to provide additional tensile strength at the point where the cornea meets the less curved sclera. A difference in the preferred orientation of collagen fibrils was observed between human and bovine corneas. Throughout the human corneal stroma, (and predominantly in the posterior stroma), collagen fibrils are preferentially aligned in the superior-inferior and nasal-temporal directions this alignment coincides with the insertion points of the rectus muscles. The proportion of aligned collagen mass (relative to the total collagen mass), which increases in all four quadrants of the peripheral human cornea, is highest in the superior-nasal and inferior-temporal regions, revealing a symmetry between the left and right cornea in terms of collagen mass distribution. Abnormalities in collagen orientation and mass distribution were seen in the majority of keratoconus corneal buttons examined. A relationship between the size and shape of the cone and the extent of the structural alterations was seen in some cases however a large variation existed between corneas. These results are consistent with a theoretical mechanism of keratoconus progression which involves enzyme action and inter-fibrillar and inter-lamellar slippage. Examination of the structural organisation of collagen in SKC mice corneas, revealed the strain to be an unsuitable model for studying human keratoconus

COVID-19 and cardiac rehabilitation

The British Association for Cardiovascular Prevention and Rehabilitation (BACPR), the British Cardiovascular Society (BCS) and the British Heart Foundation (BHF) have issued a joint position statement ‘Retention of cardiac rehabilitation services during the COVID-19 pandemic’

Corneal crosslinking - A review

Purpose: To review cross-linking the cornea using riboflavin and ultraviolet A light, which has been widely adopted, refined and applied in a range of corneal surgeries and pathologies where the strength of the cornea might be compromised. Recent findings: A large number of clinical trials have been carried out, most of which have demonstrated that standard cross-linking is a successful method to halt the progression of keratoconus or even aid regression. Summary: This review describes our current understanding of the technique, focussing on how cross-linking works, how the treatment is being optimised, the clinical results that have been reported to date and the potential use of the therapy in the treatment of other corneal disorders

An investigation into corneal enzymatic resistance following epithelium-off and epithelium-on corneal cross-linking protocols

The aim of this study was to investigate corneal enzymatic resistance following epithelium off and on riboflavin/UVA cross-linking (CXL). One hundred and fourteen porcine eyes were divided into four non-irradiated control groups and seven CXL groups. The latter comprised; (i) epithelium-off, 0.1% iso-osmolar riboflavin, 9 mW UVA irradiation for 10 min, (ii) disrupted epithelium, 0.1% hypo-osmolar riboflavin, 9 mW UVA for 10 min, (iii) epithelium-on, 0.25% hypo-osmolar riboflavin with 0.01% benzylalkonium chloride (BACS), 9 mW UVA for 10 min, (iv) epithelium-on, 5 min iontophoresis at 0.1 mA for 5 min with 0.1% riboflavin solution, 9 mW UVA for 10 min or (v) 12.5 min, (vi) epithelium-on, prolonged iontophoresis protocol of 25 min with 1.0 mA for 5 min and 0.5 mA for 5 min with 0.25% riboflavin with 0.01% BACS, 9 mW UVA for 10 min or (vii) 12.5 min. Enzymatic resistance was assessed by daily measurement of a corneal button placed in pepsin solution and measurement of corneal button dry weight after 11 days of digestion. This study revealed that the enzymatic resistance was greater in CXL corneas than non-irradiated corneas (p < 0.0001). Epithelium-off CXL showed the greatest enzymatic resistance (p < 0.0001). The prolonged iontophoresis protocol was found to be superior to all other trans-epithelial protocols (p < 0.0001). A 25% increase in UVA radiance significantly increased corneal enzymatic resistance (p < 0.0001). In conclusion, although epithelium-on CXL appears to be inferior to epithelium-off CXL in terms of enzymatic resistance to pepsin digestion, the outcome of epithelium-on CXL may be significantly improved through the use of higher concentrations of riboflavin solution, a longer duration of iontophoresis and an increase in UVA radiance