ABSTRACT
OBJECTIVES: This study was undertaken to evaluate whether the surgeons' oxygen saturation of hemoglobin was affected by the surgical mask or not during major operations. METHODS: Repeated measures, longitudinal and prospective observational study was performed on 53 surgeons using a pulse oximeter pre and postoperatively. RESULTS: Our study revealed a decrease in the oxygen saturation of arterial pulsations (SpO2) and a slight increase in pulse rates compared to preoperative values in all surgeon groups. The decrease was more prominent in the surgeons aged over 35. CONCLUSIONS: Considering our findings, pulse rates of the surgeon's increase and SpO2 decrease after the first hour. This early change in SpO2 may be either due to the facial mask or the operational stress. Since a very small decrease in saturation at this level, reflects a large decrease in PaO2, our findings may have a clinical value for the health workers and the surgeons.
Subject(s)
Hypoxia/etiology , Hypoxia/metabolism , Masks/adverse effects , Occupational Diseases/etiology , Oxygen/metabolism , Surgical Procedures, Operative , Adult , Age Factors , Female , Health Status , Heart Rate/physiology , Humans , Longitudinal Studies , Male , Middle Aged , Oximetry , Oxyhemoglobins/metabolism , Physical Exertion , Plethysmography , Prospective Studies , Stress, Psychological/metabolism , Stress, Psychological/psychology , Time FactorsABSTRACT
Contrary to what has long been suggested, the biological clock is not a poor timekeeper. In fact, it has been working in precision for millions of years as a genetically set clock, independent of environmental periodicity. However, as the Earth's rotation has gradually slowed, this internal clock has gone through a relative phase shift. Extrapolating of changes backwards through time shows that the clock was set when mammals first appeared on the planet. Interestingly, primates are the only beings that have a free-running cycle longer than 24 hours. This bioclock may be set by lunar entrainment, or may be set extraterrestrially?
Subject(s)
Biological Clocks , Circadian Rhythm , Models, Biological , Animals , Biological Evolution , Earth, Planet , Humans , Mammals/physiology , Moon , Primates/physiology , Species Specificity , Suprachiasmatic Nucleus/physiologyABSTRACT
This study was planned so as to evaluate whether magnetic field exposure has any significant effect on the pentylenetetrazol (PTZ)-induced seizures. Mice were exposed to 50 Hz, 2 G (0.2 mT) magnetic field in glass cages for 1 h. Sham exposure was produced by turning off the current while the animals were in the same exposure volume. Then, PTZ was administered intraperitoneally (i.p.) at a dose of 60 mg/kg and the animals were observed for 30 min. Subsequently, the latency to seizure onset, total seizure duration, the number of seizure episodes and mortality were recorded for each subject. There was no evidence for a significant effect of the 50 Hz magnetic field on the mean number of PTZ induced seizures, seizure latency, total seizure duration and mortality (P>0.05). As a conclusion the present study failed to provide any further support for a therapeutic potential of magnetic field.
Subject(s)
Convulsants , Electromagnetic Fields , Epilepsy, Generalized , Pentylenetetrazole , Animals , Epilepsy, Generalized/chemically induced , Epilepsy, Generalized/mortality , Epilepsy, Generalized/prevention & control , Female , Mice , Pilot ProjectsABSTRACT
In this study, time-dependent variations in the in vitro sensitivity of rat thoracic aorta rings to potassium chloride (KCl) and phenylephrine (Phe) were investigated. Animals were synchronized with a 12h light and 12h darkness (lights on 08:00-20:00) schedule, and thoracic aortas were obtained at six different times of the day (1, 5, 9, 13, 17, and 21 hours after lights on). In order to avoid endothelial influence, all experiments were performed in endothelium-denuded preparations. Responses to KCI showed time-dependent variations in all the concentrations used. Phe-induced contractions also exhibited time-dependent differences. The rhythmic pattern of Phe responses did not change with the presence of the alpha1-adrenergic antagonist prazosin. In addition, both the EC50 values of KCl and Phe, and also the K(B) values of prazosin, displayed rhythmicity. In conclusion, time of obtaining tissues is an important factor for experimental standardization in, at least, vascular smooth muscle preparations.
Subject(s)
Activity Cycles/drug effects , Aorta, Thoracic/physiology , Muscle Contraction/drug effects , Vasoconstrictor Agents/pharmacology , Activity Cycles/physiology , Animals , Aorta, Thoracic/drug effects , Male , Phenylephrine/antagonists & inhibitors , Phenylephrine/pharmacology , Potassium Chloride/pharmacology , Prazosin/pharmacology , Rats , Rats, WistarABSTRACT
It is well known that in haemodialysis patients suffering from oligoanuria, extracellular hypervolaemia develops and this hypervolaemia is the main reason for hypertension occurring in some of the patients. The absence of vasorelaxation during hypervolaemia may be secondary to an increased activity of vasoconstrictor systems and/or a decreased formation of vasodilator agents like prostaglandin E2(PGE2) and prostaglandin I2(PGI2). In the present study, arterial PGE2 and leukotriene C4(LTC4)-like activities and the effect of fluid removal on these arachidonic acid metabolites during haemodialysis were measured in normotensive and hypertensive patients. Plasma PGE2 and LTC4-like activities were significantly different between hypertensive and normotensive patients. PGE2/LTC4 ratio did not change in normotensive patients while it was increased in hypertensive patients after haemodialysis. These results indicate that haemodialysis alters the synthesis of arachidonic acid metabolites especially in hypertensive patients.
