Operative field temperature during transnasal endoscopic cranial base procedures

Background

Data regarding the safety of endoscopic skull base exploration are very scarce. With this method, fragile vital structures (cranial nerves, the optic complex, brainstem, hypothalamus or cerebral ventricles) are exposed to direct illumination within a closed space. Also, high-speed drills, cauterization and ultrasonic aspiration deliver a significant load of thermal energy. The aim of this study was to record the temperature close to the structures of the skull base and in the intradural space during the procedures performed using extended endoscopic transnasal approaches.

Methods

The temperature of the skull base was continuously recorded during six transnasal endoscopic procedures. Implantable copper-constantan thermocouples were inserted: one into the esophagus and another through the nostril to reach the operative field at the skull base.

Results

At the beginning of the procedure, the temperature of the operative field was on average 36.8 °C?±?0.80 °C, i.e. only 1 °C higher than the esophageal temperature. Then it grew continuously during the whole procedure, to eventually reach a level of 42–43 °C at the final stage, whereas the esophageal temperature remained stable. Occasionally, the temperature increased up to 45 °C during cauterization and ultrasonic aspiration, and even up to 62 °C during high-speed drilling.

Conclusion

Endoscopic skull base surgery is associated with an incessant increase of the temperature of the intraoperative field. The temperature can peak suddenly to levels which can potentially harm neural structures and influence the rate of postoperative complications.     

Effect of 1-methyl-1,2,3,4-tetrahydroisoquinoline on the protective action of various antiepileptic drugs in the maximal electroshock-induced seizure model: a type II isobolographic analysis

The aim of this study was to characterize the interaction between 1-methyl-1,2,3,4-tetrahydroisoquinoline (1-MeTHIQ—an endogenous parkinsonism-preventing substance) and various antiepileptic drugs [AEDs: clonazepam (CZP), ethosuximide (ETS), gabapentin (GBP), levetiracetam (LEV), tiagabine (TGB) and vigabatrin (VGB)] in the mouse maximal electroshock (MES)-induced seizure model. Results indicate that 1-MeTHIQ in combination with CZP (at the fixed ratios of 50:1 and 25:1), ETS (1:10) and GBP (1:1, 1:2, 1:5 and 1:10) exerted supra-additive (synergistic) interactions in the mouse MES model. In contrast, 1-MeTHIQ in combination with CZP (200:1 and 100:1), ETS (1:1, 1:2 and 1:5), LEV and VGB (1:1, 1:2, 1:5 and 1:10), and TGB (200:1, 100:1, 50:1 and 25:1) produced additive interaction in the mouse MES model. Total brain AED concentrations were unaffected by 1-MeTHIQ, and inversely, CZP, ETS and GBP had no impact on total brain concentrations of 1-MeTHIQ, indicating pharmacodynamic nature of synergistic interactions between 1-MeTHIQ and the tested AEDs in the mouse MES model. In conclusion, the supra-additive interactions of 1-MeTHIQ with CZP (at the fixed ratios of 50:1 and 25:1), ETS (1:10) and GBP (1:1, 1:2, 1:5 and 1:10) in the mouse MES model appear to be particularly favorable combinations from a clinical viewpoint. The additive combinations of 1-MeTHIQ with CZP (100:1, 50:1), ETS (1:1, 1:2 and 1:5), LEV and VGB (1:1, 1:2, 1:5, and 1:10), and TGB (200:1, 100:1, 50:1 and 25:1) seem to be neutral and worthy of consideration in further clinical practice.     

Effect of the transdermal low-level laser therapy on endothelial function

The effect of low-level laser therapy (LLLT) on the cardiovascular system is not fully established. Since the endothelium is an important endocrine element, establishing the mechanisms of LLLT action is an important issue.The aim of the study was to evaluate the effect of transdermal LLLT on endothelial function.In this study, healthy volunteers (n?=?40, age?=?20–40 years) were enrolled. N?=?30 (14 female, 16 male, mean age 30?±?5 years) constituted the laser-irradiated group (LG). The remaining 10 subjects (6 women, 4 men, mean age 28?±?5 years) constituted the control group (CG). Participants were subjected to LLLT once a day for three consecutive days. Blood for biochemical assessments was drawn before the first irradiation and 24 h after the last session. In the LG, transdermal illumination of radial artery was conducted (a semiconductor laser λ?=?808 nm, irradiation 50 mW, energy density 1.6 W/cm² and a dose 20 J/day, a total dose of 60 J). Biochemical parameters (reflecting angiogenesis: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiostatin; antioxidative status: glutathione (GSH) and the nitric oxide metabolic pathway: symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA) and l-arginine) were assessed. In the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation.     

Catecholamines and their <Emphasis Type="Italic">O</Emphasis>-methylated metabolites in vitreous humor in hypothermia cases

Purpose

The aim of this study was to assess the diagnostic value of catecholamines and their O-methylated metabolites in vitreous humor samples in identifying antemortem cold exposure and fatal hypothermia in the forensic casework.

Methods

A total of 80 autopsy cases (40 hypothermia fatalities and 40 cases in which hypothermia as the main or contributory cause of death was excluded) were selected for this study. Catecholamines and their O-methylated metabolites were measured in urine and vitreous humor samples collected at autopsy.

Results

Urine catecholamine and their O-methylated metabolite concentrations were significantly higher in hypothermia-related deaths. On the other hand, measurements in vitreous humor samples did not reveal statistically significant differences between hypothermia-related deaths and controls.

Conclusions

Globally considered, our findings seem to suggest that, contrary to urine catecholamines and their O-methylated metabolites, vitreous levels of these compounds appear to be of limited value in characterizing human antemortem stress reactions due to cold exposure and can hardly be used in the forensic setting to support the diagnosis of hypothermia.

     

Sleep disturbances in women with polycystic ovary syndrome

Sleep disturbances in women with Polycystic Ovary Syndrome (PCOS) have been reported in recent years. The majority of published studies are related to Obstructive Sleep Apnea (OSA) while not many researches have analyzed any other causes of sleep disturbances. A group of ninety five women with Polycystic Ovary Syndrome were enrolled into the study. Sleep disturbances were assessed using validated questionnaires. On the grounds of Athens Insomnia Scale (AIS) evaluation a clinically significant insomnia was ascertained in 12.6% of women with PCOS, while according to Insomnia Severity Index (ISI) in 10.5%. Clinically significant insomnia according to both AIS and ISI, occurred significantly more often in women with PCOS than in women without PCOS based on the chi-square test. The Mann–Whitney U test revealed statistically significant difference between women with and without PCOS based on total values of ISI. An excessive daytime sleepiness occurred at 7.4% of women with PCOS. Statistically significant dependance between: clinically significant insomnia in both AIS and ISI and excessive daytime sleepiness indicated by Epworth Sleepiness Scale (ESS) was observed. Sleep disorders are common in women with PCOS. Screening assessment of sleep disturbances should be a part of medical diagnostics in women with PCOS.