Moderate traumatic brain injury is linked to acute behaviour deficits and long term mitochondrial alterations.

Traumatic brain injury (TBI) remains one of the leading causes of death and disability worldwide. Mild TBI may lead to neuropsychiatric sequelae, including memory loss and motor impairment. Mitochondrial dysfunction and oxidative stress have a contributory role in several neurological disorders; however, their association with mitophagy in mild TBI is unclear. TBI was induced in female Sprague Dawley (SD) rats using a New York University Impactor (10 g, impactor head 2.5 mm diameter, weight drop 50 mm) and compared to sham surgery controls. The novel object recognition and error ladder tests were performed at 24 hours and for 6 weeks post injury, and the brains were examined histologically to confirm the extent of injury. Mitochondria manganese superoxide dismutase (MnSOD) and the oxidative phosphorylation (OXPHOS) complexes I-V (CI-CV), as well as mitophagy markers, dynamin related protein 1 (DRP-1), LC3A/B and PTEN-induced putative kinase 1 (PINK-1), were measured in the penumbra by western blot. At 24 hours sham rats performed as expected on a novel object recognition test while TBI rats showed cognitive deficits at the early time points. TBI rats also showed more early motor deficits on a horizontal ladder, compared with the sham rats. MnSOD, OXPHOS CI, CIII and CV protein levels were significantly lower in the TBI group at 24 hours. DRP-1, LC3A/B I and II, and PINK-1 were increased at 6 weeks suggesting abnormal mitophagy. Moderate TBI caused immediate cognitive and mild motor functional deficits in the rats that did not persist. Reduced antioxidative capacity and possibly compromised mitochondrial function may affect the long term functional recovery.

The use of simulation as a novel experiential learning module in undergraduate science pathophysiology education.

Teaching of pathophysiology concepts is a core feature in health professional programs, but it can be challenging in undergraduate medical/biomedical science education, which is often highly theoretical when delivered by lectures and pen-and-paper tutorials. Authentic case studies allow students to apply their theoretical knowledge but still require good imagination on the part of the students. Lecture content can be reinforced through practical learning experiences in clinical environments. In this study, we report a new approach using clinical simulation within a Human Pathophysiology course to enable undergraduate science students to see "pathophysiology in action" in a clinical setting. Students role played health professionals, and, in these roles, they were able to interact with each other and the manikin "patient," take a medical history, perform a physical examination and consider relevant treatments. Evaluation of students' experiences suggests that using clinical simulation to deliver case studies is more effective than traditional paper-based case studies by encouraging active learning and improving the understanding of physiological concepts.

Mitochondrial dysfunction in a rat model and the related risk of metabolic disorders.

OBJECTIVE: To explore whether kidney deficiency (KYD) is prone to metabolic disorders may be linked to impaired mitochondrial function in thermogenesis and metabolic tissues. METHODS: A rat model of KYD was used, which was established using Sprague Dawley rat dams with warm preference subjected to herbal treatment that can improve kidney . The human relevance was confirmed by reduced serum corticosterone levels, and increased preference for warm location. RESULTS: KYD Rats were underdeveloped. Adenosine-triphosphate (ATP) production was reduced in the brown fat, but increased in the muscle. However, oxidative phosphorylated complexes to generate ATP and mitochondrial biogenesis marker were reduced in both tissues. When the second insult of high-fat diet (HFD) was introduced, KYD rats gained less weight yet developed more severe lipid and glucose metabolic disorders. This may be driven by disregulated liver gluconeogenesis marker forkhead box protein O1 and lipid metabolic regulator cholesterol 7 alpha-hydroxylase. CONCLUSION: KYD rats exhibited reduced mito-chondrial function in the brown fat, but were partially compensated by skeletal muscle, associated with the phenotype of warm preference and metabolic disorder, which was further exacerbated by additional HFD consumption. Future studies can focus on treatment targetting mitochondria function to reverse this phenotype.

Headspace analysis of E-cigarette fluids using comprehensive two dimensional GC×GC-TOF-MS reveals the presence of volatile and toxic compounds.

The analysis of electronic cigarrete (E-cigarette) fluids by high performance liquid chromatography or gas chromatography (GC) coupled to mass spectrometry (MS), GC hyphenated to flame-ionisation detection, or nuclear magnetic resonance spectroscopy poses many challenges due to the complex matrix and extremely high number of compounds present. In order to overcome these challenges, this study focused on the detection of the multiple complex compounds classes produced by the pyrolysis of E-cigarette liquids using comprehensive two dimensional gas chromatography (GCxGC) coupled to time of flight (TOF)-MS. Gas samples were prepared by heating E-liquids inside aluminium tins for 5 min. The tins were placed in a sand bath, which was temperature controlled at 200 °C. The samples were collected using thermal desorption tubes connected to volatile organic compound (VOC) sampling pump attached and subsequently analysed using GCxGC-TOF-MS. The greater peak resolution obtained when using GCxGC-TOF-MS allowed to distinguish many toxic compounds and VOCs that could not be detected by the other methods mentioned above. As a result, a comprehensive list of volatile compounds emitted from E-cigarette fluids when heated was established, which might allow a better understanding of potential health effects of vaping. Heating E-liquids to moderate temperature results in the emission of over 1000 volatile compounds of which over 150 are toxic. These compounds are either present in the liquid or can be formed during storage or heating leading to a more complex volatile profile of E-cigarette liquids than previously assumed. The application of GCxGC-TOF-MS allows the elucidation of this profile and therefore a better understanding of possible health implications.

L-Carnitine and extendin-4 improve outcomes following moderate brain contusion injury.

There is a need for pharmaceutical agents that can reduce neuronal loss and improve functional deficits following traumatic brain injury (TBI). Previous research suggests that oxidative stress and mitochondrial dysfunction play a major role in neuronal damage after TBI. Therefore, this study aimed to investigate two drugs known to have antioxidant effects, L-carnitine and exendin-4, in rats with moderate contusive TBI. L-carnitine (1.5 mM in drinking water) or exendin-4 (15 µg/kg/day, ip) were given immediately after the injury for 2 weeks. Neurological function and brain histology were examined (24 h and 6 weeks post injury). The rats with TBI showed slight sensory, motor and memory functional deficits at 24 h, but recovered by 6 weeks. Both treatments improved sensory and motor functions at 24 h, while only exendin-4 improved memory. Both treatments reduced cortical contusion at 24 h and 6 weeks, however neither affected gliosis and inflammatory cell activation. Oxidative stress was alleviated and mitochondrial reactive oxygen species was reduced by both treatments, however only mitochondrial functional marker protein transporter translocase of outer membrane 20 was increased at 24 h post injury. In conclusion, L-carnitine and exendin-4 treatments immediately after TBI can improve neurological functional outcome and tissue integrity by reducing oxidative stress.

The effect of Meibomian lipids and tear proteins on evaporation rate under controlled in vitro conditions.

The lipid layer of the tear film is associated with preventing evaporative loss. The ability of human Meibomian lipids to reduce evaporation in vitro was tested. Films of human or animal Meibomian lipids or mixtures of cholesterol and phosphatidylcholine were spread on the surface of either artificial buffer or on whole tears and placed on a mass balance that was enclosed in a sealed chamber. The temperature was adjusted to 37 degrees C and gas flow was controlled. Increasing the amounts of Meibomian lipids gave a very small reduction in evaporation. It was concluded from these in vitro experiments that prevention of evaporation from the tear film is not due to the Meibomian lipids alone, but is more likely to be due to a complex interaction between components of the aqueous and the Meibomian lipids.

Role of chloride channels in regulating the volume of acinar cells of the rabbit superior lacrimal gland.

PURPOSE: To characterize the outward chloride currents (Cl(OR)) in single acinar cells isolated from the rabbit superior lacrimal gland (RSLG) to investigate the hypothesis that Cl(OR) may have a role in regulating the volume of RSLG acini. METHODS: Cl(OR) was characterized by using patch-clamp electrophysiology. Confocal microscopy was used to measure intracellular calcium concentration ([Ca(2+)](i)) and cell volume. Cell volume was altered by superfusing the cells with a hyposmotic solution. RESULTS: The Cl(OR) current contributed 33% of total membrane conductance. With normal osmotic conditions, the Cl(OR) current was activated by [Ca(2+)](i) with an EC(50) of 10(-8) M. A decrease in intracellular pH from 7.4 to 6.8 totally inhibited Cl(OR) current activity. Continuous superfusion of hyposmotic solution caused (1) an increase in cell volume that peaked within 4 minutes and gradually returned to baseline levels after 12 minutes, (2) an increase in [Ca(2+)](i) that peaked between 6 and 8 minutes and gradually returned to baseline levels after 15 minutes, and (3) an increase the Cl(OR) current that peaked within 6 minutes after commencement of perfusion and quickly returned to baseline levels. CONCLUSIONS: The Cl(OR) current appears to be triggered by an increase in cell volume and then deactivates within the period of raised [Ca(2+)](i) during hyposmotic stress, suggesting that Cl(OR) may be an initiating event for volume homeostasis. This effect would be important during RSLG tear secretion, which usually involves cell volume changes and is accompanied by intracellular pH changes in the presence of the raised [Ca(2+)](i) to support secretion.