γ－去氢骆驼蓬碱等咔啉类生物碱的辐射防护作用

γ－去氢骆驼蓬碱等咔啉类生物碱的辐射防护作用利国威，桑培根，潘国英（中山医科大学肿瘤防治中心广州５１００６０）从新疆产蒺藜科植物骆驼蓬（ＰｅｈａｎｕｍｈａｒｍａｌａＬ．）的种子中分离得到３个化合物，其中γ－去氢骆驼蓬碱（γ－ｈａｒｍｉｎｅ，Ⅰ）为新化...     

Defecography commode

A mobile wooden commode was designed and built for use in defecography. The commode is made of 1/2-inch-thick plywood with birch veneer and a solid clear pine seat. Water or copper sheets are recommended for radiation filtration. A radiopaque ruler attached to the commode with a spring enables midline measurements. The modifications suggested by the authors have helped with setup and have improved the images acquired.     

In-plane vascular imaging: pulse sequence design and strategy

Magnetic resonance (MR) angiography is a noninvasive method of obtaining images without contrast agents. Recent developments in sequence design have allowed images of moving spins to be obtained without a loss of signal by rephasing the spins with three or four gradient pulses to compensate for constant velocity or acceleration, respectively. At longer echo times (TE), this approach allowed for low readout gradients and high signal-to-noise ratios. Angiograms with a resolution of 300 micron were obtained. With additional sequences that allow some dephasing but minimal signal loss, separate images of arteries and veins were obtained. Phase information was used to estimate flow velocity. Application of the rephasing scheme to gradient-echo sequences allowed for ungated, fast MR angiograms. Acceleration correction was important for long TE sequences, but velocity-corrected, gradient-echo sequences with a very short TE were comparable to velocity- and acceleration-corrected, gradient-echo sequences with slightly longer TEs. With ungated three-dimensional, gradient-echo sequences, susceptibility artifacts were minimized and excellent contrast-to-noise ratios were obtained.     

Faecal flora in spondyloarthropathy

Enterobacteria, in particular Klebsiella spp., have been implicated in the aetiopathogenesis of ankylosing spondylitis. A comprehensive examination of the faecal flora of 82 patients with ankylosing spondylitis, either primary (67), or in association with inflammatory bowel disease (4), reactive arthritis (6) or psoriatic arthritis (5), was performed and compared with that of a control population (36) of healthy individuals. The range of flora identified was similar in both populations and there was no increased isolation rate of Klebsiella or other proposed arthritogenic organism in those with spondyloarthropathy. In those patients in whom Klebsiella was identified, its presence was not related to disease activity, the erythrocyte sedimentation rate or C-reactive protein.      

Spinal cord compression due to metastatic disease: diagnosis with MR imaging versus myelography

To determine the efficacy of magnetic resonance (MR) imaging and myelography for the diagnosis of spinal cord compression due to metastatic disease, the authors prospectively examined 70 patients who had known or suspected spinal involvement by malignancy. Most MR examinations consisted of T1-weighted sagittal imaging of the entire spine, with additional sequences as needed for clarification. Extradural masses were found in 46 patients, 25 of whom had cord compression. For extradural masses causing cord compression, the sensitivity and specificity of MR imaging was .92 and .90, respectively, compared with .95 and .88 for myelography. For extradural masses without cord compression the sensitivity and specificity of MR imaging was .73 and .90, versus .49 and .88 for myelography. MR imaging was much more sensitive for metastases to bone (.90 vs .49), as expected. MR imaging is an acceptable alternative to myelography for diagnosing spinal cord compression and is preferable as a first study because it is noninvasive and better tolerated.     

Tetravinyl-tetramethylcyclo-tetrasiloxane (tetravinyl D4) is a mutagen in Rat2lambda lacI fibroblasts

Small fragments of silicone gels injected intraperitoneally have been used to induce plasmacytomas in genetically susceptible mice. Silicone oils, in contrast to silicone gels, are apparently not tumorigenic in the mouse plasmacytoma system. The reason for this difference as well as the mechanism of silicone gel-induced plasmacytoma development is poorly understood. We chose to examine the possibility that low molecular wt silicone compounds such as siloxanes, leaking from the complex silicone gel matrix into the surrounding tissue, may be mutagenic. We postulate that this mutagenicity may be a critical determinant of the plasmacytoma inducing potency of silicone gels. Six siloxane compounds, either linear or cyclic di-, tri-, or tetrasiloxanes substituted with methyl or vinyl moieties, were selected as model compounds to study mutagenicity in Rat2lambda lacI fibroblasts in vitro. Using phage lambda-derived lacI/lacZ genes as target/reporter genes to quantitate mutagenesis, and gamma-cyclodextrin as vehicle to effectively deliver siloxanes, we found that exposure to 50 microM of tetravinyl-tetramethylcyclo-tetrasiloxane (tetravinyl D4) resulted in a modest 1.7-fold increase of mutant frequencies over controls in Rat2lambda lacI cells. In related toxicity experiments, tetravinyl D4 was shown to perturb lipid membranes leading to a loss of cytosolic glutathione (GSH), which by itself resulted in a 1.5-fold increased mutant rate in Rat2lambda lacI cells. We conclude that certain siloxanes may act as direct mutagens in mammalian cells. In addition, siloxane-induced mutagenicity may be enhanced by the depletion of intracellular GSH caused by the interaction of lipophilic siloxanes with cell membranes.      

Thyroglossal duct cyst or ectopic thyroid gland?

Abstract: We report a 16-year-old boy with an anterior midline neck mass clinically diagnosed as a thyroglossal duct cyst. An ultrasound scan performed prior to surgery suggested a normally located thyroid gland. Following surgical excision of the presumed thyroglossal duct cyst the patient became hypothyroid. A radioisotope scan confirmed no active thyroid tissue. A pitfall in the ultrasonographic identification of the thyroid gland is discussed.     

药物在室内自然光照射下的贮存期预测方法研究

以己酸孕酮注射液为例,研究了药物在自然光和不同灯光照射下的含量变化规律,预测了药物在室内自然光照射下的贮存期。找出了不同光源对药物稳定性影响的等效数量关系,使在今后的研究中可以用灯光为光源预测药物在室内自然光照射下的贮存期。己酸孕酮注射液在光照试验中含量变化服从零级反应规律:C=C₀-K(Et),在室内自然光照射下的贮存期约为1.9年。