Effect of anaesthetic agents on infarct volume in the rat

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Effect of duration of ischaemia on infarct volume in the rat

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In vivo neuroprotection of melatonin against focal cerebral ischaemia in the rat

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Melatonin pretreatment protects against focal cerebral ischemia in the rat

Melatonin (MT) possesses many properties of an ideal neuroprotectant. In this study, the neuroprotective effects of exogenous MT were tested in a middle cerebral artery occlusion (MCAO) stroke model. Adult male Sprague-Dawley rats (280 to 360 g) were anesthetized with sodium pentobarbital (60 mg/kg, I.P.) to undergo reversible right-sided endovascular MCAO for 3 hours. Arterial blood pressure, heart rate and cerebral blood flow (CBF) were monitored, and rectal temperature was kept between 36.5 and 37.5 ºC throughout anesthesia. One I.P. dose of MT (at 1.5, 5, or 15 mg/kg) or the vehicle was given 30 minutes before onset of ischemia. The rats were decapitated on day 3 of MCAO, and their brains were stained with 2% triphenyltetrazolium chloride for determination of infarction. Results were compared using 2-tailed student’s t test. When compared to the relative infarct volume of 31.8±3.3% (mean±SEM; 16 rats) in the control group, treatment with MT reduced the relative infarct volume in a dose-dependent manner (30.5±3.2% in the 1.5 mg/kg group [17 rats]; 15.9±2.2% in the 5 mg/kg group [16 rats], P < 0.05; 21.4±3.0% in the 15 mg/kg group [15 rats], P < 0.05). There was no significant difference in heart rate, arterial blood pressure and CBF among the groups. We concluded that a single dose of MT between 5 and 15 mg/kg protects against focal cerebral ischemia, when given 30 minutes before onset of ischemia. The above doses of MT do not produce significant hemodynamic effects nor alter the CBF during ischemia and reperfusion. Supported by the CRCG Research Grant 10202138 of the University of Hong Kongpublished_or_final_versio

Clinical learning environments across two different healthcare settings using the undergraduate clinical education environment measure

Data availability: The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.Copyright © The Author(s) 2023. Background: The clinical placements of our medical students are almost equally distributed across private and public sectors. This study aims to assess medical students’ perceptions of their Clinical learning Environment (CLE) across these two different healthcare settings, using the Undergraduate Clinical Education Environment Measure (UCEEM). Methods: 76 undergraduate medical students (Year 5 and 6), were invited to participate. Data were collected using an online UCEEM with additional questions related to demographics and case load exposure. The UCEEM consists of two overarching domains of experiential learning and social participation, with four subdomains of learning opportunities, preparedness, workplace interaction, and inclusion. Results: 38 questionnaires were received. Of 225 responses to the individual UCEEM items, 51 (22.6%) scored a mean of ≥ 4 (range 4-4.5, representing strong areas), 31 (13.7%) scored a mean of ≤ 3 (range 2.1-3, needing attention) and 143 (63.6%) scored a mean of 3.1–3.9 (areas that could be improved). The majority (63%) of the case load exposure responses scored a mean of ≥ 4 (range 4-4.5). Compared to the private sittings, there is a significant reduction in total UCEEM (p = 0.008), preparedness for student entry (p = 0.003), and overarching dimension of social participation (p = 0.000) scores for the public sector. Similarly, both workplace interaction patterns and student inclusion and equal treatment scored significantly lower for the public sector (p = 0.000 and p = 0.011 respectively). Two out of three case load exposure items scored significantly higher for the public sector (p = 0.000). Discussion: The students’ CLE perceptions were generally positive. The lower UCEEM ratings in the public sector items were related to student entry preparedness, workplace interactions, student inclusiveness and workforce equity of treatment. In contrast the students were exposed to more variety and larger number of patients in the public sector. These differences indicated some significantly different learning environments between the two sectors.Not applicable