Biomedical subjects
A Coombes
Publications and source records attributed to A Coombes.
Preventing exposure keratopathy in the critically ill: a prospective study comparing eye care regimes.
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Honey: a potent agent for wound healing?
Although honey has been used as a traditional remedy for burns and wounds, the potential for its inclusion in mainstream medical care is not well recognized. Many studies have demonstrated that honey has antibacterial activity in vitro, and a small number of clinical case studies have shown that application of honey to severely infected cutaneous wounds is capable of clearing infection from the wound and improving tissue healing. The physicochemical properties (eg, osmotic effects and pH) of honey also aid in its antibacterial actions. Research has also indicated that honey may possess antiinflammatory activity and stimulate immune responses within a wound. The overall effect is to reduce infection and to enhance wound healing in burns, ulcers, and other cutaneous wounds. It is also known that honeys derived from particular floral sources in Australia and New Zealand (Leptospermum spp) have enhanced antibacterial activity, and these honeys have been approved for marketing as therapeutic honeys (Medihoney and Active Manuka honey). This review outlines what is known about the medical properties of honey and indicates the potential for honey to be incorporated into the management of a large number of wound types.
Role of the cross-linking enzyme tissue transglutaminase in the biological recognition of synthetic biodegradable polymers.
The calcium-dependent cross-linking enzyme tissue transglutaminase (tTgase, type II) is a potential novel player at the cell surface, where its contribution to cell adhesion and stabilization of the extracellular matrix is becoming increasingly recognized. We investigated whether tTgase enhances the biological recognition of poly (DL lactide co-glycolide) (PLG), poly (epsilon-caprolactone) (PCL), and poly (L lactide) (PLA), biomaterials widely used in medical implants. Three cell-model systems consisting of human osteoblasts, endothelial cells (ECV-304), and Swiss 3T3 fibroblasts were utilized, in which tTgase expression was modulated by gene transfer, and the ability of cells to spread on these polymers was quantified in relation to the altered level of expressed tTGase. Results show that over-expression of tTgase in human osteoblasts positively correlated with cell spreading on PLG, while no attachment and spreading was found on PCL and PLA. Antisense silencing of tTgase in the endothelial cells led to a marked reduction of cell spreading on all polymers. The hydrophobic nature of PLC also appeared to favor endothelial cell attachment. Spreading of Swiss 3T3 fibroblasts on these biomaterials was only slightly affected by increased expression of tTgase, although cell spreading on control glass was increased. We propose that the consideration of tTgase-mediated bioactivity in novel biomaterials may improve cell attachment and promote biocompatibility.
Bilateral acute retinal necrosis and herpes simplex type 2 encephalitis in a neonate.
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Bilateral cataract extraction can be safely done within 48 hours.
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Posterior capsular opacification prevention: IOL design and material.
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Horner's syndrome following internal jugular vein cannulation.
We present two cases of Horner's syndrome occurring following uncomplicated internal jugular venous cannulation. An awareness of this potential complication will reduce confusion over the aetiology of anisocoria in critically ill patients. This consideration is important, since lesions in the central nervous system or carotid dissection following trauma might otherwise be suspected.
Sex discrimination: how do we tell the difference between male and female faces?
People are remarkably accurate (approaching ceiling) at deciding whether faces are male or female, even when cues from hair style, makeup, and facial hair are minimised. Experiments designed to explore the perceptual basis of our ability to categorise the sex of faces are reported. Subjects were considerably less accurate when asked to judge the sex of three-dimensional (3-D) representations of faces obtained by laser-scanning, compared with a condition where photographs were taken with hair concealed and eyes closed. This suggests that cues from features such as eyebrows, and skin texture, play an important role in decision-making. Performance with the laser-scanned heads remained quite high with 3/4-view faces, where the 3-D shape of the face should be easiest to see, suggesting that the 3-D structure of the face is a further source of information contributing to the classification of its sex. Performance at judging the sex from photographs (with hair concealed) was disrupted if the photographs were inverted, which implies that the superficial cues contributing to the decision are not processed in a purely 'local' way. Performance was also disrupted if the faces were shown in photographic negatives, which is consistent with the use of 3-D information, since negation probably operates by disrupting the computation of shape from shading. In 3-D, the 'average' male face differs from the 'average' female face by having a more protuberant nose/brow and more prominent chin/jaw. The effects of manipulating the shapes of the noses and chins of the laser-scanned heads were assessed and significant effects of such manipulations on the apparent masculinity or femininity of the heads were revealed. It appears that our ability to make this most basic of facial categorisations may be multiply determined by a combination of 2-D, 3-D, and textural cues and their interrelationships.
Recognising facial surfaces.
The extent to which faces depicted as surfaces devoid of pigmentation and with minimal texture cues ('head models') could be matched with photographs (when unfamiliar) and identified (when familiar) was examined in three experiments. The head models were obtained by scanning the three-dimensional surface of the face with a laser, and by displaying the surface measured in this way by using standard computer-aided design techniques. Performance in all tasks was above chance but far from ceiling. Experiment 1 showed that matching of unfamiliar head models with photographs was affected by the resolution with which the surface was displayed, suggesting that subjects based their decisions, at least in part, on three-dimensional surface structure. Matching accuracy was also affected by other factors to do with the view-points shown in the head models and test photographs, and the type of lighting used to portray the head model. In experiment 2 further evidence for the importance of the nature of the illumination used was obtained, and it was found that the addition of a hairstyle (not that of the target face) did not facilitate matching. In experiment 3 identification of the head models by colleagues of the people shown was compared with identification of photographs where the hair was concealed and eyes were closed. Head models were identified less well than these photographs, suggesting that the difficulties in their recognition are not solely due to the lack of hair. Women's heads were disproportionately difficult to recognise from the head models. The results are discussed in terms of their implications for the use of such three-dimensional head models in forensic and surgical applications.
Gerald Jacob Frengley.
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