Quenton Wessels

Comparative in vitro study of honey based and silver based wound preparations on cell viability

BACKGROUND Since the early 1980s a plethora of dressings has been developed to promote wound healing. The objective of this study was to compare the effects of silver based dressings and honey based dressings on cell viability. MATERIALS AND METHODS In this blinded study, keratinocyte cultures were exposed to prepared extracts of each of the following wound dressings for 40 h: Silver based dressings: Acticoat, Actisorb, Askina, Atrauman-Ag and Contreet. Honey based dressings: Melladerm gel, Melladerm mesh, Melladerm plus and Mellarsorb. Controls consisted of cells that were cultured in the same medium, and under the same conditions as those exposed to extracts. RESULTS All dressing extracts had an effect on cell viability. Changes in cell morphology from different wound dressing extracts were noted and compared with control groups after 24 h of incubation. CONCLUSIONS In the silver based extracts group, Atrauman-silver and Acticoat had the most viable cells. For the honey based group, the most viable cells were seen with Melladerm mesh and Mellasorb. There was no significant difference between the best performing silver and honey based wound preparations with regard to cell viability.

Anatomical evidence for an endocrine activity of the vomeronasal organ in humans

The mammalian vomeronasal organ (VNO) is a well‐adjusted chemosensory structure that facilitates social and reproductive behavior in mammals. The existence, locality, and function of this organ in human adults remain a matter of discussion. Most authors now agree that a neuroreceptive function of the adult human VNO can be excluded due to the absence of both neural receptive cells associated with the VNO in other mammals despite the enigmatic reports on the effects of pheromones on human behavior. Adult cadavers form European (Caucasoid) descent were used in this article and parasagittal dissection of the heads allowed access to the nasal septa, which were grossly examined for the VNO openings. Tissue samples were collected, embedded in gelatin and serially sectioned through cryomicrotomy. Nissl staining was performed as well as immunohistochemically stained with an antibody against calcium‐binding protein. The findings presented here confirm the bilateral presence of the VNO in adult cadavers and demonstrate morphological connections of VNO receptor cells with the underlying capillaries. In addition, possible endocrine activity associated with the epithelium of this chemosensory structure has been demonstrated by the expression of calcium‐binding protein in a part of these receptor cells. Clin. Anat. 27:856–860, 2014.

Microbes, molecular mimicry and molecules of mood and motivation

The hypothesis proposed is that functional disorders, such as irritable bowel syndrome, chronic fatigue syndrome and anorexia nervosa are caused by auto-antibodies to neuronal proteins induced by molecular mimicry with microbial antigens. The age incidence of these conditions, the marked female excess, increase with economic and technological advance, precipitation by infection, and the paucity of histological changes are all consistent with the hypothesis. It can be tested directly using human sera to search for cross reaction with brain proteins in model systems such as Drosophila melanogaster. The conditions might be amenable to treatment using pooled immunoglobulin. Identification and elimination from the microbial flora of the bacteria that express the cross reacting antigens should be possible.

Reflecting on interprofessional education in the design of space and place:lessons from Namibia

Abstract Education at the University of Namibia, School of Medicine and School of Pharmacy relies on a community-centred curriculum. The aim is to nurture “7-star” doctors and pharmacists that will address the current social and health needs within the country. A sound understanding of the interplay between learning and the learning environment is said to improve interprofessional educational activities. This relationship is dependent on constrictive alignment of not only the aspects of pedagogy, but also that of educational leadership in context of the current and social health needs. In this report, we reflect on the interprofessional-learning environment that was created out of necessity within a Namibian context.

Anatomy Education in Namibia: Balancing Facility Design and Curriculum Development.

The anatomy curriculum at Namibias first, and currently only, medical school is clinically oriented, outcome‐based, and includes all of the components of modern anatomical sciences i.e., histology, embryology, neuroanatomy, gross, and clinical anatomy. The design of the facilities and the equipment incorporated into these facilities were directed toward simplification of work flow and ease of use by faculty, staff, and students. From the onset, the integration of state of the art technology was pursued to facilitate teaching and promote a student‐centered pedagogical approach to dissections. The program, as realized, is comprised of three 16‐week semesters with seven hours of contact time per week, namely three hours of lectures and four hours of dissection laboratory and microscopy time. Set outcomes were established, each revolving around clinical cases with integrated medical imaging. The design of the facility itself was not constrained by a legacy structure, allowing the School of Medicine, in collaboration with architects and contractors, to design the building from scratch. A design was implemented that allows for the sequential processing of cadaveric material in a unidirectional flow from reception, to preparation, embalming, storage, dissection, and maceration. Importantly, the odor of formaldehyde typically associated with anatomy facilities was eliminated outside of the dissection areas and minimized within via a high‐performance ventilation system. By holistically incorporating an integrated curriculum, facility design, and teaching at an early stage, the authors believe they have created a system that might serve as a model for new anatomy programs. Anat Sci Educ.

Enhanced stabilization of collagen-based dermal regeneration scaffolds through the combination of physical and chemical crosslinking

The use of collagen in the biomedical device industry has led to major advances in soft tissue repair. This is attributed largely to the favourable biological and physiochemical properties of collagen. Regenerative medicine and tissue engineering favoured the use of this biomaterial and various commercial products have become available in the past few decades. This study aims to develop a collagen and chondroitin-6-sulphate dermal regeneration scaffold with enhanced resistance against enzymatic degradation. Frozen slurries (0.5% collagen) were dried under vacuum, coated with silicone, crosslinked and then thoroughly rinsed. The scaffolds were subjected to a range of quantitative and qualitative tests that included: scanning electron microscopy analysis, collagenase enzymatic degradation, and cytotoxicity assessment. Scaffold resistance to enzymatic degradation was manipulated after dehydrothermal treatment by employing combinations of crosslinking agents, such as glutaraldehyde and / or carbodiimide, with or without the presence of L-lysine. Results indicate that highly porous (mean pore diameter of 87.3 µm), bioactive, non-cytotoxic tissue engineering matrices were obtained. Enhanced stability of these scaffolds was achieved through extensive crosslinking and suggests the potential to prevent in vivo wound contraction sufficiently.

Engineered alternative skin for partial and full-thickness burns

Engineered alternative skin in all its forms and shapes serve to provide temporary or permanent wound closure such as in the case of partial and full-thickness burns. The need for collagen-based regeneration templates is motivated by the fact that dermal regeneration of full-thickness injuries does not occur spontaneously and is inundated by contraction and scarring. Partial-thickness burns in turn can regress as a result of infection and improper treatment and require appropriate treatment. Nylon-silicone laminates such as Biobrane®, and more recently AWBAT®, address this by serving as a temporary barrier. Enhanced collagen-based scaffolds today, although not perfect, remain invaluable. Our initial approach was to characterize the design considerations and explore the use of collagen in the fabrication of a dermal regeneration matrix and a silicone-nylon bilaminate. Here we expand our initial research on scaffold fabrication and explore possible strategies to improve the outcome of collagen-scaffold medicated wound healing.

The posterior intercostal vein: A thermoregulatory gateway to the internal vertebral venous plexus

The internal vertebral venous plexus (IVVP) plays a putative role in thermoregulation of the spinal cord. Cold cutaneous venous blood may cool, while warm venous blood from muscles and brown fat areas may warm the spinal cord. The regulating mechanisms for both cooling and warming are still unknown. Warm venous blood mainly enters the IVVP via the intervertebral veins. In the thoracic area these veins are connected to the posterior intercostal veins. In this study, anatomical structures were investigated that might support the mechanisms by which warmed venous blood from the intercostal muscles and the recently described paravertebral patches of brown adipose tissue are able to drain into the vertebral venous plexus. Therefore, tissue samples from human cadavers (n = 21) containing the posterior intercostal vein and its connections to the IVVP and the azygos veins were removed and processed for histology. Serial sections revealed that the proximal parts of the posterior intercostal veins contained abundant smooth muscle fibers at their opening into the azygos vein. Furthermore, the walls of the proximal parts of the posterior intercostal veins contain plicae that allow the vessel to dilate, thereby allowing it to serve as a pressure chamber. It is suggested that a cold induced closure of the intercostal/azygos opening can result in retrograde blood flow from the proximal posterior intercostal vein towards the IVVP. This blood flow would be composed of warm blood from the paravertebral brown adipose tissue and blood containing metabolic heat from the muscles draining into the intercostal veins. Clin. Anat. 26:735–740, 2013.

Using artificial passageways to facilitate the movement of wildlife on Namibian farmland

Wildlife-proof fencing is increasing in extent as a result of the growing wildlife industry on private lands in southern Africa. In environments where such fences hinder the movements of free-ranging wildlife, the provision of artificial passageways can restore connectivity for some species. We tested the use of 49 discarded car tyres as wildlife passageways along the border of a Namibian wildlife farm. Tyres were installed into a wildlife-proof fence to reduce regular warthog (Phacochoerus africanus) damage to the fence and to provide connectivity and dispersal opportunities for selected indigenous wildlife species between adjacent farmland properties. The total cost for all 49 tyre installations was USD 252, which is significantly cheaper than daily fence patrols and maintenance. In addition, one tyre was monitored specifically for large carnivore activity with a motion-triggered camera trap (n = 96 trap days between August and December 2010). Eleven mammalian species used the tyre as a passageway and both cheetahs (Acinonyx jubatus) and leopards (Panthera pardus) made regular and repeated use of the tyre. Nine independent recordings of cheetahs, representing seven individuals, were made. One leopard was photographed four times. The suitability of discarded tyres as cost-effective artificial wildlife passageways for a range of mammalian species is stressed.

Edinburgh, the Scottish pioneers of anatomy and their lasting influence in South Africa

The history of the origin of anatomy education in South Africa is the history of an arduous journey through time. The lasting influence of Edinburgh came in the form of Robert Black Thomson. He was a student and assistant of Sir William Turner who gave rise to the first chair of anatomy and the establishment of a department at the South African College, known today as University of Cape Town. Thomson was later succeeded by Matthew Drennan, a keen anthropologist, who was revered by his students. This Scottish link prevailed over time with the appointment of Edward Philip Stibbe as the chair of anatomy at the South African School of Mines and Technology, which later became the University of the Witwatersrand. Stibbe’s successor, Raymond Arthur Dart, a graduate of the University of Sydney, was trained in an anatomy department sculpted on that of Edinburgh by Professor James Thomas Wilson. Wilson’s influence at the University of Sydney can be traced back to Edinburgh and William Turner through Thomas Anderson Stuart. Both Dart and Robert Broom, another Scot, were considered as Africa’s wild men by the late Professor Tobias. Here, the authors explore the Scottish link and origins of anatomy pedagogy in South Africa.