Heat Sink Effect on Tumor Ablation Characteristics as Observed in Monopolar Radiofrequency,Bipolar Radiofrequency,and Microwave,Using Ex Vivo Calf Liver Model

Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink.     

The effect of light-emitting diode and laser on mandibular growth in rats

Objective:To evaluate the effect of a light-emitting diode (LED) and/or low-level laser (LLL) with or without the use of anterior bite jumping appliances (also known as functional appliances [FAs]) on mandibular growth in rats.Materials and Methods:Thirty-six 8-week-old male Sprague-Dawley rats weighing 200 g were obtained from Charles River Canada (St. Constant, QC, Canada) and were divided into six groups of six animals each. Groups were as follows: group 1: LLL; group 2: LLL + FA; group 3: LED; group 4: LED + FA; group 5: FA; and group 6: control (no treatment). Mandibular growth was evaluated by histomorphometric and micro computed tomographic (microCT) analyses.Results:The LED and LED + FA groups showed an increase in all condylar tissue parameters compared with other groups.Conclusion:The LED-treated groups showed more mandibular growth stimulation compared with the laser groups.     

Gastric volvulus caused by paraesophageal hernia complicating mid-trimester pregnancy

A 36-year-old woman, who was 19 weeks pregnant presented with epigastric pain and a one-week history of repeated vomiting. Endoscopy revealed twisted stomach. CT scan of the chest showed figure of eight stomach consistent with gastric volvulus. Confirmation of diagnosis was made by laparatomy in which reduction of the oedematous stomach and excision of ischemic omental patch and repair of a huge paraesophageal hernia were performed. Two days after operation, abortion took place. Few days later, rapid deterioration in renal and hepatic function occurred followed by maternal death.     

Iron status: a possible risk factor for the first febrile seizure

PURPOSE: We conducted a controlled study to investigate the relation of iron status and first febrile seizure (FFS). METHODS: Measures of iron sufficiency including hemoglobin concentration (HB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and plasma ferritin (PF) were prospectively measured in 75 children with FFS and compared with 75 controls matched for age and sex with febrile illnesses without convulsions. RESULTS: Mean ferritin level was significantly lower in cases with FFS (29.5 +/- 21.3 microg/L) than in controls (53.3 +/- 37.6 microg/L) with p = 0.0001. The proportion of subjects with a PF level 相似文献   

Effects of 4-aminopyridine, GABA and bicuculline on cutaneous receptive fields of cat dorsal horn neurons

4-Aminopyridine (4-AP), bicuculline and GABA were applied locally to dorsal horn cells in the lumbar spinal cord in Nembutal-anaesthetized cats and in spinal cats. 4-AP expanded the cutaneous receptive field of 29 of 33 cells tested. Bicuculline and GABA had little or no effect on receptive field size.     

Occlusion of dentinal tubules and selective block of pulp innervation prevent the nociceptive behaviour induced in rats by intradental application of irritants

Objectives: Application of irritants on the exposed dentine of the incisors has been shown to produce aversive behaviour in awake rats. This study aims to demonstrate that the observed aversion is due to the infiltration of irritants through the dentinal tubules and the activation of capsaicin sensitive fibres in the tooth pulp. Methods: Different groups of rats were subjected, under anaesthesia, to cutting of the distal 2 mm of their lower incisors and the fixation of an artificial crown that allows the application of 10-15 μl of solution. Several procedures were followed to prevent the action of the irritants including occlusion of the dentinal tubules, local application of lidocaine, selective ablation of the capsaicin sensitive primary afferents (CSPA) or incisor pulpectomy; the reactions to intradental application of either capsaicin (1%) or formalin (2.5%) were tested using a newly designed behavioural score. Results: Occlusion of dentinal tubules produced significant attenuation of the nociceptive behaviour induced by dentinal application of either capsaicin or formalin. Similar results were observed following either local block with lidocaine (2%), selective ablation of capsaicin sensitive afferents or total denervation by pulpectomy. Conclusions: The present results confirm the hypothesis of infiltration of irritants to the incisor pulp through the dentinal tubules and suggest that the reported inflammatory reaction and hyperalgesia are mediated, to a large extent, by capsaicin sensitive primary afferents.     

Continuous perfusion with morphine of the orbitofrontal cortex reduces allodynia and hyperalgesia in a rat model for mononeuropathy

Recent imaging reports demonstrate the activation of the orbitofrontal cortical (OFC) area during acute and chronic pain. The aim of this study was to compare the effects of chronic perfusion of this area with morphine on nociception in control rats and in rats subjected to mononeuropathy. Chronic perfusion of morphine, using miniosmotic pumps, produced significant and naloxone-reversible depression of tactile and cold allodynias and thermal hyperalgesia, observed in neuropathic rats, while it produced significant elevation and naloxone insensitive increase of acute nociceptive thresholds in control rats. The observed results support the idea that this area is a component of a flexible cerebral network involved in pain processing and perception.     

Reducing inflow occlusion,occlusion duration and blood loss during hepatic resections

Background

To assess the changes in blood loss during hepatic resection with improved haemostatic devices such as a bipolar sealing device and a topical haemostatic agent.

Methods

This retrospective clinical study of prospectively collected data will assess hepatic resections performed by a single surgeon between 2005 and 2013, with the introduction of the two haemostatic techniques in 2009.

Results

A total of 371 hepatic resections (214 from 2005 to 2008 and 157 from 2009 to 2013) were included in this study. Compared with the conventional hepatic resection (2005–2008), the use of haemostatic techniques (2009–2013) significantly reduced the need for inflow occlusion (OR: 0.37, 95% CI: 0.24–0.57, P < 0.001), overall occlusion time (20.8 min versus 25.9 min, P = 0.04) and transfusion requirement (4.6% versus 12%, OR: 0.35, 95% CI: 0.14–0.90, P = 0.02). Mean overall blood loss was reduced post‐2009; however, the decrease was not statistically different (401.3 mL versus 470.8 mL, P = 0.27). Subgroup analysis revealed that blood loss was more than halved post‐2009 compared with pre‐2009 for patients who received pre‐operative chemotherapy (324.6 mL versus 738.5 mL, P = 0.005).

Conclusion

The use of a bipolar sealing device and a topical haemostatic agent reduces the need for inflow occlusion, overall occlusion time and transfusions in all patients compared with conventional hepatic resections.