海藻酸钙/聚组氨酸微胶囊的毒性试验研究

为了考察海藻酸钙/聚组氨酸微胶囊的毒性特征,我们利用MTT比色法和小鼠尾静脉注射法,分别考察了该微胶囊的细胞毒性和急性全身毒性。结果表明：微胶囊浓度≤1.0mg/mL时,材料对L929细胞生长无明显抑制作用;微胶囊浸提液即使在高浸提比（10.0mg/mL）下,浸提产物也无细胞毒性作用。急性全身毒性试验结果显示：微胶囊浸提液不引起急性全身毒性反应,表明微胶囊浸提液无有毒的沥滤物和降解产物产生。说明海藻酸钙/聚组氨酸微胶囊无明显毒性。     

细菌对噬菌体感染的抵抗

噬菌体对其宿主菌具有特异性感染力,反之,宿主菌对噬菌体的感染具有抵抗现象.根据噬菌体侵入宿主的不同阶段,可以将宿主菌对噬菌体的天然抵抗机制分为4个主要的类别吸附抑制,流产感染,限制-修饰系统和穿入阻滞.此外,还有源于噬菌体的抗性作用以及通过人工插入突变获得的广谱噬菌体抗性菌株等.     

Miscibility and Intermolecular Specific Interactions in Blends of Poly(hydroxyether sulfone) and Poly(N‐vinylpyrrolidone)

Summary: The blends of poly(hydroxyether sulfone) (PHES) with poly(N‐vinylpyrrolidone) (PVPy) were investigated by means of differential scanning calorimetry (DSC) and FTIR spectroscopy. The miscibility of the blend system was established on the basis of the thermal analysis results. DSC showed that the PHES/PVPy blends prepared by casting from N,N‐dimethylformamide (DMF) possessed single, composition‐dependent glass transition temperatures, indicating that the blends are miscible in the entire composition. The experimental glass transition temperatures have higher values than those calculated on the basis of additive behavior; the variation of the glass transition temperatures of the blends was accounted for by the Kwei equation. FTIR studies indicate that competitive hydrogen bonding interactions exist upon addition of PVPy to the system, which were involved in the self‐ and cross‐association, i.e., ? OH···O?S, ? OH···OH of PHES and ? OH···O?C< of PVPy. The FTIR spectra in the range of the sulfonyl stretching vibrations showed that the hydroxyl‐associated sulfonyl groups are partially “set free” upon addition of PVPy to the system. The IR spectroscopic investigation of both the model compounds and the PHES/PVPy blends suggests that the strength of the hydrogen bonding interactions in the blend system increases in the following order: ? OH···O?S, ? OH···OH and ? OH···O?C<.

Plot of glass transition temperature for PHES/PVPy blends as a function of weight fraction of PVPy. The prediction of the Kwei equation yields the values of k = 1 and q = 122.     

借助移相法采用多部CCD数码相机提高帧率的技术

对于科学研究工作来说，时间分辨率和空间分辨率都是十分重要的，在设计相应的图像处理系统时必须两者兼顾。对于生命科学及工业等领域而言，希望图像处理系统不仅有较高的时间分辨率，还要有较高的空间分辨率。本文提出一种利用多部CCD数码相机、采用移相法获取高分辨牢和高摄录帧率的技术，此技术可应用于普通CCD数码相机组成的复合摄录系统。     

组织工程血管基质的制备与改性

目的：完全脱除猪胸主动脉细胞，对脱细胞血管基质进行改性，增强基质的力学强度，制备组织工程血管支架材料。方法：取家猪的新鲜去除外膜胸主动脉20根，随机分成4组，分别采用胰蛋白酶、TritonX-100及十二烷基硫酸钠（SDS）作为脱细胞试剂对猪胸主动脉进行脱细胞处理，并对脱细胞后的血管基质进行改性，采用HE染色、弹力纤维染色、力学性能测试，以评价脱细胞效果以及材料的力学性能。结果：采用1％TritonX-100单独作用84h既能完全脱除细胞，同时又可完整保留血管基质的三维结构，对胶原纤维、弹力纤维的损伤小，是一种较理想的脱细胞方法。对脱细胞后的基质进行冷冻干燥及真空热交联处理，能有效提高材料的机械强度，冷冻干燥24h后真空120℃下热交联处理12h所获得的材料的机械强度最好，断裂强度可达到1．70MPa。结论：以脱细胞血管基质经冷冻干燥和真空热交联处理后，可以作为血管组织工程的支架材料。     

Diastematomyelia--clinical manifestation and treatment outcome.

Diastematomyelia is a rare congenital anomaly characterized by a division of the spinal cord or the filum terminale into two parts. In Korea, only one case has been reported. The authors have operated on 5 cases of diastematomyelia with septum since July, 1978. The ages ranged from 1 to 44 years (median; 11 years). There were 2 boys, 2 girls and an adult man. The disease manifested by cutaneous abnormalities and neurological or orthopedic deficits. Pain was a chief complaint in the adult patient. The symptoms had progressed in 3 cases. The diagnosis was made correctly by CT myelography or MRI in 4 cases. The median septum was located at the lumbar area in 4 cases and at the lumbosacral region in 1 case. Associated abnormalities included low lying conus (5 cases), lipoma (2 cases), thickened filum terminale (1 case), hemilipomyelomeningocele (1 case) and syrinx (1 case). The median septum was removed. The dural sleeve adjoining the septum was resected and the dural sac was reconstructed. The role of MRI in the diagnosis and planning of surgery and the high frequency of associated low lying conus were emphasized. Though the surgical treatment relieved pain, it did not reverse the neurological deficits or orthopedic deformities significantly, which suggests the beneficial effects of early surgical intervention in the cases with progressive symptoms.     

Flat depressed early colon cancer--a case report.

A flat depressed early colon cancer (FDEC) is characterized by non-polypoid growth pattern, no association of adenomatous tissues and a tendency of even small lesions toward submucosal invasion and lymph node metastasis. It supports de novo carcinogenesis of colorectal cancer, although most colorectal cancers arise in pre-existing adenoma (adenoma-carcinoma sequence). There have been few reports of small depressed cancers because of the difficulty in colonoscopic detection and the rapid development to ulcerating advanced cancers. We report a case of flat depressed early colon cancer confined to mucosa detected by indigo carmine contrast colonoscopy.     

Studies on hypoxia. 8. Ultrastructural and biochemical effects of prolonged exposure on rat parotid glands

The effect of chronic hypoxia upon the rat parotid gland is studied by electron microscopy and biochemistry. Male Sprague-Dawley rats are subjected to 88% N₂ and 12% O₂ at less than 2 psi pressure for 7 days. For electron microscopy, the tissues are perfusion-fixed, embedded and sectioned in a routine manner. In the biochemical studies, rats are injected with ³H-phenylalanine (2 μCi/g; s.i. ～ 5 Ci/mM) 60 min before sacrifice. Fresh glands are then prepared for analysis of amylase (Cibachrome-amylase substrate method), DNA (diphenylamine reaction), and total protein (Lowry method). The radioactivity in the acid precipitable and soluble fractions is determined by liquid scintillation spectrometry. The control animals are pair-fed and handled identically except that they are maintained in an ambient atmosphere. The ultrastructure of the hypoxic cells is altered in several areas. The Golgi apparatus demonstrates a decrease in organization and contains fewer transport vesicles. The rough-surfaced endoplasmic reticulum is broken and presents many vesicular and concentric profiles. The mitochondria have undergone several changes including swelling, clumping of intramitochondrial matrix, and fragmentation of cristase. The nucleus demonstrates a fibrillar pattern and contains a reduced amount of heterochromatin. The biochemical results indicate that, compared with controls, the hypoxic cells contain only 55% of amylase and 84% of the DNA, and thus suggest a drastic reduction of exportable protein production and an increase in cellular size, respectively. On the contrary, the incorporation of ³H-phenylalanine demonstrates an increase in the amount of radioactivity in the acid precipitable fraction of the hypoxic cells. These results lead to the conclusion that hypoxic stress causes a suppression of exportable protein synthesis, but may induce other cytoplasmic protein production, reflecting the biochemical and morphologic adjustment of the cell to a recovery phase.