An Isolator System for minimally invasive surgery: the new design

Background - The risk of obtaining a postsurgical infection depends highly on the air quality surrounding the exposed tissue, surgical instruments, and materials. Many isolators for open surgery have been invented to create a contained sterile volume around the exposed tissue. With the use of an isolator, a surgical procedure can be performed outside sterile environments. The goal of this study was to design an Isolator System (IS) for standard laparoscopic instruments while instrument movements are not restricted. Methods - The developed IS consists of a sleeve to protect the instrument shaft and tip and a special balloon to protect the incision and trocar tube. A coupling mechanism connected at the sleeve allows instrument changes without contamination of the isolated parts. Smoke tests were performed to show that outside air does not enter the new IS during a simulated laparoscopic procedure. Eight test runs and one baseline run inside a contained volume filled with thick smoke were performed to investigate whether smoke particles entered the Isolator System. Filters were used to identify smoke entering the Isolator System. Results - Seven filters showed no trace of smoke particles. In one test run, a part of the IS loosened and a small brown spot was visible. The filter from the baseline run was completely covered with a thick layer of particles, proving the effectiveness of the test. During all test runs, the isolated instrument was successfully locked on and unlocked from the isolated trocar. Instrument movements gave no complications. After removal of the isolated instrument, it took three novices an average of 3.1 (standard deviation (SD), 0.7) seconds to replace it correctly on the isolated trocar. Conclusions - The designed IS for laparoscopy can increase sterility in environments where sterility cannot be guaranteed. The current design is developed for laparoscopy, but it can easily be adapted for other fields in minimally invasive surgery.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

Space- and time-resolved investigation on diffusion kinetics of human skin following macromolecule delivery by microneedle arrays

Microscale medical devices are being developed for targeted skin delivery of vaccines and the extraction of biomarkers, with the potential to revolutionise healthcare in both developing and developed countries. The effective clinical development of these devices is dependent on understanding the macro-molecular diffusion properties of skin. We hypothesised that diffusion varied according to specific skin layers. Using three different molecular weights of rhodamine dextran (RD) (MW of 70, 500 and 2000 kDa) relevant to the vaccine and therapeutic scales, we deposited molecules to a range of depths (0–300 µm) in ex vivo human skin using the Nanopatch device. We observed significant dissipation of RD as diffusion with 70 and 500 kDa within the 30 min timeframe, which varied with MW and skin layer. Using multiphoton microscopy, image analysis and a Fick’s law analysis with 2D cartesian and axisymmetric cylindrical coordinates, we reported experimental trends of epidermal and dermal diffusivity values ranging from 1–8 µm2 s-1 to 1–20 µm2 s-1 respectively, with a significant decrease in the dermal-epidermal junction of 0.7–3 µm2 s-1. In breaching the stratum corneum (SC) and dermal-epidermal junction barriers, we have demonstrated practical application, delivery and targeting of macromolecules to both epidermal and dermal antigen presenting cells, providing a sound knowledge base for future development of skin-targeting clinical technologies in humans

Can medical therapy mimic the clinical efficacy or physiological effects of bariatric surgery?

The number of bariatric surgical procedures performed has increased dramatically. This review discusses the clinical and physiological changes, and in particular, the mechanisms behind weight loss and glycaemic improvements, observed following the gastric bypass, sleeve gastrectomy and gastric banding bariatric procedures. The review then examines how close we are to mimicking the clinical or physiological effects of surgery through less invasive and safer modern interventions that are currently available for clinical use. These include dietary interventions, orlistat, lorcaserin, phentermine/topiramate, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, pramlintide, dapagliflozin, the duodenal–jejunal bypass liner, gastric pacemakers and gastric balloons. We conclude that, based on the most recent trials, we cannot fully mimic the clinical or physiological effects of surgery; however, we are getting closer. A ‘medical bypass' may not be as far in the future as we previously thought, as the physician's armamentarium against obesity and type 2 diabetes has recently got stronger through the use of specific dietary modifications, novel medical devices and pharmacotherapy. Novel therapeutic targets include not only appetite but also taste/food preferences, energy expenditure, gut microbiota, bile acid signalling, inflammation, preservation of β-cell function and hepatic glucose output, among others. Although there are no magic bullets, an integrated multimodal approach may yield success. Non-surgical interventions that mimic the metabolic benefits of bariatric surgery, with a reduced morbidity and mortality burden, remain tenable alternatives for patients and health-care professionals

Neuroprotection by adenosine in the brain: From A1 receptor activation to A2A receptor blockade

Adenosine is a neuromodulator that operates via the most abundant inhibitory adenosine A1 receptors (A1Rs) and the less abundant, but widespread, facilitatory A2ARs. It is commonly assumed that A1Rs play a key role in neuroprotection since they decrease glutamate release and hyperpolarize neurons. In fact, A1R activation at the onset of neuronal injury attenuates brain damage, whereas its blockade exacerbates damage in adult animals. However, there is a down-regulation of central A1Rs in chronic noxious situations. In contrast, A2ARs are up-regulated in noxious brain conditions and their blockade confers robust brain neuroprotection in adult animals. The brain neuroprotective effect of A2AR antagonists is maintained in chronic noxious brain conditions without observable peripheral effects, thus justifying the interest of A2AR antagonists as novel protective agents in neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, ischemic brain damage and epilepsy. The greater interest of A2AR blockade compared to A1R activation does not mean that A1R activation is irrelevant for a neuroprotective strategy. In fact, it is proposed that coupling A2AR antagonists with strategies aimed at bursting the levels of extracellular adenosine (by inhibiting adenosine kinase) to activate A1Rs might constitute the more robust brain neuroprotective strategy based on the adenosine neuromodulatory system. This strategy should be useful in adult animals and especially in the elderly (where brain pathologies are prevalent) but is not valid for fetus or newborns where the impact of adenosine receptors on brain damage is different

Causes of rail staff fatigue: results of qualitative analysis and a diary study

The purpose of this study was to investigate the causes of fatigue among rail staff by analysing qualitative data and conducting an online diary study. It had a closer look at the experience of fatigue among rail staff and brought a more detailed blueprint picture of fatigue and its causes in the rail staff’s real-life. Study 1 analysed 133 responses of qualitative data from rail staff, and Study 2 was a diary study examining fatigue and its related risk factors before and after work, on the first and the last day of a working week in 19 rail staff. The findings from the two studies, using different methodologies, showed similar results that fatigue among rail staff was a result of heavy workload and a high workload would further increase fatigue. Fatigue before work mainly resulted from sleep quality, length of sleep, and the time spent on commute, while fatigue after work resulted from the perceived workload and shift type. Evidence has demonstrated that overtime work, specific shift patterns, insufficient rest days between opposed shifts, and poor timing of breaks during work were also associated with fatigue

Hydration Characteristics of Paddy

The hydration characteristics of paddy (Cv. Parijata) were studied for soaking under atmospheric and elevated pressures and for steaming operations. Soaking treatments under atmospheric condition were carried out at 40, 50, 60 and 70°C water temperature. The pressure levels for hydrostatic soaking were 2.0, 4.0 and 6.0 kg/cm2 with a constant water temperature of 70°C. Steaming was carried out at 0.5, 1.0. 1.5,2.0 and 2.5 kg/cm2 pressure levels. For all the studies, 3 levels of initial moisture contents were taken. The soaking temperature and pressure and steaming pressure greatly influenced the moisture absorption by the grain and, thus, affected the time requirement. The diffusion coefficients, diffusion constants and activation energy for moisture diffusion were also calculated for the different treatments. The diffusion coefficient was independent of moisture content and showed Arrhenius type relationship with absolute temperatures of soaking and steaming. Empirical relationships were developed to predict the moisture gain by paddy at any time and process condition