Superficial- and deep-tissue temperature increases in anesthetized dogs during exposure to high specific absorption rates in a 1.5-T MR imager

Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.     

Computed tomographic angiography of the body

Large and medium-sized blood vessels can be identified on extracranial computed tomographic (CT) scans when a combination of infusion and bolus injection of conventional contrast material is administered. The cases illustrated in this report show that CT angiography can sometimes offer clinically useful information not present on CT scans obtained without contrast injection.     

Psychological Correlates of Outcome after Coronary Artery Bypass Graft

Background

Psychological effects of Coronary Artery Bypass graft (CABG) have been of interest all over the world but there is a paucity of Indian work.

Methods

30 patients undergoing CABG at a service hospital were included. All patients filled a specially designed proforma. Mini Mental Status Examination, Hospital anxiety and depression scale, Coronary scale, Seattle angina questionnaire and Euro-QOL 5D were performed before and seven days after CABG.

Results

43.3% had significant anxiety and 30% had significant depression before CABG. Following CABG, 36.67% of the patients had significant anxiety while 40% had significant depression. On the Seattle angina questionnaire, physical limitation reduced from 71.6 ± 7.9 to 53.1 ± 14.6. There was significant improvement in treatment satisfaction from 37.8 ± 6.1 to 59.4 ± 4.2 following CABG. On th euro quality of life scale (EQ5D) health status improved from 38.17 ± 9.51 before CABG to 68.5 ± 5.28 after CABG.

Conclusion

There is a significant incidence of anxiety and depression in patients undergoing CABG, both before and after surgery.Key Words: CABG, anxiety, depression     

应用非甾体抗炎药对高血压合并冠状动脉疾病患者的有害作用

慢性疼痛综合征患者常应用非甾体抗炎药( non-steroidal anti-inflammatory drugs,NSAID).许多这类患者有潜在的高血压和冠状动脉疾病.临床试验和系统性分析显示,选择性环氧化酶2抑制剂增加心肌梗死的风险[J].该发现可能导致更普遍地应用非选择性NSAID作为治疗慢性疼痛综合征的替代手...     

4α-phorbol 12,13-didecanoate activates cultured mouse dorsal root ganglia neurons independently of TRPV4

Background and Purpose

The Ca²⁺-permeable cation channel TRPV4 is activated by mechanical disturbance of the cell membrane and is implicated in mechanical hyperalgesia. Nerve growth factor (NGF) is increased during inflammation and causes mechanical hyperalgesia. 4α-phorbol 12,13-didecanoate (4αPDD) has been described as a selective TRPV4 agonist. We investigated NGF-induced hyperalgesia in TRPV4 wild-type (+/+) and knockout (–/–) mice, and the increases in [Ca²⁺]_i produced by 4αPDD in cultured mouse dorsal root ganglia neurons following exposure to NGF.

Experimental Approach

Withdrawal thresholds to heat, von Frey hairs and pressure were measured in mice before and after systemic administration of NGF. Changes in intracellular Ca²⁺ concentration were measured by ratiometric imaging with Fura-2 in cultured DRG and trigeminal ganglia (TG) neurons during perfusion of TRPV4 agonists.

Key Results

Administration of NGF caused a significant sensitization to heat and von Frey stimuli in TRPV4 +/+ and –/– mice, but only TRPV4 +/+ mice showed sensitization to noxious pressure. 4αPDD stimulated a dose-dependent increase in [Ca²⁺]_i in neurons from +/+ and –/– mice, with the proportion of responding neurons and magnitude of increase unaffected by the genotype. In contrast, the selective TRPV4 agonist GSK1016790A failed to stimulate an increase in intracellular Ca²⁺ in cultured neurons. Responses to 4αPDD were unaffected by pretreatment with NGF.

Conclusions and Implications

TRPV4 contributes to mechanosensation in vivo, but there is little evidence for functional TRPV4 in cultured DRG and TG neurons. We conclude that 4αPDD activates these neurons independently of TRPV4, so it is not appropriate to refer to 4αPDD as a selective TRPV4 agonist.