Journal of Arak University of Medical Sciences

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Showing 3 results for Temperature

Effects of Intravenous Fluids Temperature on Perioperative Hemodynamic Situation, Postoperative Shivering and Recovery in Orthopedic Surgeries

Hadi Hasankhani , Eisa Mohammadi, Farhad Moazami , Manijheh Mokhtari, Mohammad Mahdi Naghizadeh,
Volume 6, Issue 4 (12-2003)

Abstract

Introduction: Postoperative hypothermia is physiologically stressful by elevating blood pressure, heart rate and plasma catecholamine concentration. This study conducted to evaluate the effects of intravenous fluids temperature on perioperative hemodynamic situation.
Materials and Methods: This was a randomized clinical trial study Perioperative pulse rate, blood pressure, intraoperative esophageal and skin temperature were measured in 60 volunteer patients undergoing orthopedic surgeries subjects randomly divided into two groups according to intraoperative IV fluids management. In 30 patients (hypothermia group) all IV fluids infused were at room temperature. In the other 30 patients (normothermia group) all IV fluids were warmed using and dry IV fluid warmer.
Results: The core and skin temperature of hypothermia and normothermia group decreased significantly from induction of anesthesia toward end of surgery but its reduction was more in hypothermia group (P<0.005). Postoperative mean arterial blood pressure increased significantly more in hypothermia group versus normothermia group (P<0.005). Shivering was observed in 21 of 30 hypothermia and 11 of 30 normothermia group (p<0.005) and recovery time was significantly lower in normothermia group (36±5 vs. 26±3 min, P<0.005).
Conclusion: Infusion of warm fluids helps to reduce the variation of postoperative mean arterial blood pressure, core and skin temperature, occurrence of shivering and recovery time.

The Effects of Temperature Changes on Human Prion Protein Conformation Using Molecular Dynamic Simulation

Mohammad Reza Dayer, Nooshin Azari, Nematollah Razmi, Mohammad Saeid Dayer,
Volume 17, Issue 7 (10-2014)

Abstract

Background: Prion diseases are neurodegenerative disorders which ultimately results in the death of their victims. They are caused by structural transformation of cellular prion (PrPC) to its &beta-rich and anomalous isoform (PrPSc) and the accumulation of amyloid fibrillar deposits in the central nervous system. The precise mechanism underling this conversion is yet to be well understood. This study aimed to investigate the effect of non physiological temperatures on the misfolding mechanism of the human prion protein.

Materials and Methods: The crystal structure of human prion protein (90-231), (PDB code: 2Lej) in pdb format was used as a starting structure in this study. Three model structures of this coordinate structure were used separately to simulate PrPC at 27 , 37 and 47 . Molecular dynamic simulations were then performed using double-precision MPI version of GROMACS 4.5.5 for 10 ns and the results were analyzed using SPSS software, SPDBV and VebLab programs.

Results: The change of temperature from 37 to 27 or 47 induced significant structural changes to PrPC. These tempratures caused PrPC to attain a more folded and less flexible tertiary structure compared to its native structure at 37 . They, also, reduce protein-solvent hydrogen bonds and therefore increasing access of hydrophobic solvent to PrPC which may be behind the lower water solubility of PrPC and its increased resistance to proteolytic degradations.

Conclusion: This study shows that changes of temperatures accelerate structural changes of PrPC and reduce its solubility while rendering it vulnerable to transition into PrPSc.

Prediction of Changes in Temperature-Humidity Index in the Coming Decades According to the Climate Change Phenomenon based on Radiative Forcing Scenarios in a Dry Climate

Dr Mehdi Asghari, Dr Gholamabbas Fallah Ghalhari, Dr Marzieh Abbasinia, Dr Farbod Ebadifard Azar, Dr Fahimeh Shakeri, Dr Mohammad Javad Ghanadzade, Mr Gholam Heidar Teimori, Dr Sanaz Karpasand, Dr Hossein Safari,
Volume 26, Issue 3 (9-2023)

Abstract

Introduction: One of the biggest environmental challenges of the 21st century is the phenomenon of climate change and global warming, which can cause numerous health problems. One significant health issue associated with climate change is the increase in the prevalence of heat stress, particularly in occupational encounters in hot outdoor environments. So this study aimed to predict and model temperature and humidity indices in the coming decades in a dry climate.
Methods: This study obtained daily atmospheric parameters, including minimum temperature, maximum temperature, and relative humidity of Kerman station, representing a dry climate, for a period of 30 years (1965 to 2005) from the meteorological organization. Modeling of these parameters and calculation of the Temperature and Humidity Index (THI) were performed using the atmospheric general circulation model HadGEM2-ES and the CORDEX dynamic microscaler model. Three different radiative forcing scenarios, including optimistic (RCP 2.6), intermediate (RCP 4.5), and pessimistic (RCP 8.5), were considered for the coming decades (three 30-year periods from 2011 to 2099). The Ethics Committe of Iran University of Medical Sciences (IUMS) approved the present study (Code: IR.IUMS.REC.1400.020).
Results: The results of the study showed an increasing trend for minimum and maximum temperature parameters in all three time periods using the three scenarios considered. Moreover, the increase in temperature in the decades of 2099-2071 was more pronounced compared to the previous decades. The results also demonstrated an increasing trend in the THI index based on all three scenarios. The average results obtained using these scenarios showed an increase of 2.11, 2.53, and 3.3 degrees Celsius, respectively, in this index until the end of the last century compared to the base decades.
Conclusions: Overall, the increase in temperature and the investigated THI index in the studied station, based on all three scenarios, will lead to changes in thermal comfort. Higher levels of thermal discomfort will not only occur in hot months and seasons but also in other seasons. Therefore, proper planning should be implemented to address the adverse effects of climate change on people's health.

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