巴戟天和恩施巴戟的蒽醌化合物

从巴戟天(Morinda officinalis How.)根的氯仿提取物中,分离得八个蒽醌化合物,其中二个为新化合物,它们的结构为1,6-二羟基-2,4-二甲氧基蒽醌(1,6-dihydroxy-2,4-dimethoxyanthraquinone,V),1,6-二羟基-2-甲氧基蒽醌(1,6-dihydroxy-2-methoxy-anthraquinone,Ⅵ)。从恩施巴戟(Damnacanthus indicus Linn.)根的氯仿提取物中,分离得七个蒽醌化合物,其中一个为新化合物,其结构为1,4-二甲氧基-2α-羟基蒽醌(1,4-dimethoxy-2-hydroxyanthraquinone,ⅩⅢ)。     

Identification of glutathione conjugates of 2,3-dibromopropene in male ICR mice

Hepatotoxic potential of 2, 3-dibromopropene (2, 3-DBPE) and its conjugation with glutathione (GSH) were investigated in male ICR mice. Treatment of mice with 20, 50, and 100 mg/kg of 2, 3-DBPE for 24 h caused elevation of serum alanine aminotransferase and aspartate aminotransferase activities. The hepatic content of GSH was not changed by 2, 3-DBPE. Meanwhile, the GSH content was slightly reduced when mice were treated with 2, 3-DBPE for 6 h and significantly increased 12 h after the treatment. Subsequently, a possible formation of GSH conjugate of 2, 3-DBPE was investigated in vivo. After the animals were treated orally with 20, 50, and 100 mg/kg of 2, 3-DBPE, the animals were subjected to necropsy 6, 12, and 24 h later. A conjugate of S-2-bromopropenyl GSH was identified in liver and serum treated with 100 mg/kg of 2, 3-DBPE by using liquid chromatography-electrospray ionization tandem mass spectrometry. The protonated molecular ions [M+H]+ of S-2-bromopropenyl GSH were observed at m/z 425.9 and 428.1 in the positive ESI spectrum with a retention time of 6.35 and 6.39 min, respectively. In a time-course study in livers following an oral treatment of mice with 100 mg/kg of 2, 3-DBPE for 6, 12, and 24 h, the 2, 3-DBPE GSH conjugate was detected maximally 6 h after the treatment. The present results suggested that 2, 3-DBPE-induced hepatotoxicity might be related with the production of its GSH conjugate.     

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.     

Validation of the rat model of cryptogenic infantile spasms

Purpose: To determine whether a new model of cryptogenic infantile spasms consisting of prenatal priming with betamethasone and postnatal trigger of spasms by N‐methyl‐d ‐aspartate (NMDA) responds to chronic adrenocorticotropic hormone (ACTH) treatment, and has electroencephalography (EEG) signature, efficacy of treatments, and behavioral impairments similar to those in human infantile spasms. Methods: Rats prenatally primed with betamethasone on gestational day 15 were used. Spasms were triggered with NMDA between postnatal days (P) 10 and 15 in a single session or in multiple sessions in one subject. The expression of spasms was compared to prenatally saline‐injected controls. Effects of relevant treatments (ACTH, vigabatrin, methylprednisolone, rapamycin) were determined in betamethasone‐primed rats. In the rats after spasms, behavioral evaluation was performed in the open field and elevated plus maze on P20–22. Key Findings: NMDA at P10–15 (the rat “infant” period) triggers the spasms significantly earlier and in greater numbers in the prenatal betamethasone‐exposed brain compared to controls. Similar to human condition, the spasms occur in clusters. Repeated trigger of spasms is associated with ictal EEG electrodecrements and interictal large‐amplitude waves, a possible rat variant of hypsarrhythmia. Chronic ACTH treatment in a randomized experiment, and chronic pretreatment with methylprednisolone significantly suppress the number of spasms similar to the human condition. Pretreatment with vigabatrin, but not rapamycin, suppressed the spasms. Significant behavioral changes occurred following multiple bouts of spasms. Significance: The model of infantile spasms has remarkable similarities with the human condition in semiology, EEG, pharmacologic response, and long‐term outcome. Therefore, the model can be used to search for novel and more effective treatments for infantile spasms.     

Torsional strength and toughness of nickel-titanium rotary files

Introduction

The aim of this investigation was to compare torsional strength, distortion angle, and toughness of various nickel-titanium (NiTi) rotary files.

Methods

Five NiTi rotary instruments with different cross-sectional geometries were selected: TF and RaCe with equilateral triangle, ProTaper with convex-triangle, ProFile with U-shape, and Mtwo with S-shape. The size 25/.06 taper of TF, RaCe, ProFile, and Mtwo and the ProTaper F1 files were tested, all with the same diameter at D5. A metal mounting block with a cubical hole was constructed in which 5 mm of the file tip was rigidly held in place by filling the mold with a resin composite. The files were subjected to clockwise rotation at 2 rpm in a torsion tester. The torque and angular distortion were monitored until the file failed. The data were compared statistically for the yield and ultimate strengths, plastic hardening period, and toughness.

Results

TF and RaCe had significantly lower yield strength than other systems. TF had a significantly lower ultimate strength than other files, whereas Mtwo showed the greatest. ProFile showed the highest distortion angle at break, followed by TF. ProFile also showed the highest toughness value, whereas TF and RaCe both showed a lower toughness value than the others (P < .05). Fractographic examination revealed typical pattern of torsional fracture for all brands, characterized by circular abrasion marks and skewed dimples near the center of rotation.

Conclusions

Under the limitations of the present study, the 5 tested NiTi rotary files showed a similar mechanical behavior under torsional load, with a period of plastic deformation before actual torsional breakage but with unequal strength and toughness value.