柱切换HPLC法研究米托蒽醌毫微粒冻干静脉注射剂的药代动力学

建立了血浆中米托蒽醌的柱切换高效液相色谱测定法,测定和比较了米托蒽醌溶液型注射剂和毫微粒冻干静脉注射剂在家兔体内的血药曲线,并研究比较了二者的药代动力学参数。米托恩醌毫微粒冻干注射剂使米托蒽醌在血中浓度大为降低,血中分布容积增大了近5倍,体内平均驻留时间延长了2倍多。表明米托蒽醌毫微粒有明显的体内长效作用,结合其体内分布试验研究结果,表明其具有明显肝靶向分布作用。     

人工牛黄的光解

人工牛黄是广泛用于中成药配方的中药代用品。本文用漫反射光谱法研究了人工牛黄样品在人工光源照射下发生颜色变化的光解规律:在三种光源下,其光解均属二步表观一级反应动力学,即光解曲线是由两段斜率不同的直线组成,初期的光解速度较其后的快2倍左右;不同光源下,紫外灯光解速度最快,荧光高压汞灯次之,碘钨灯最慢;表观光解常数与光波长有关,但基本不随光强度和照射时间乘积改变。而光解时间则与光强度成反比。从得到的动力学方程可预测不同条件下的褪色时间。研究表明,人工牛黄复方中,发生光解的主要成分是胆红素,其余成分不发生引起颜色变化的光解,但在第二步反应中对胆红素的光解有明显影响。     

Pathogenesis of shigella diarrhea. VII. Evidence for a cell membrane toxin receptor involving β1 {arrow} 4-linked N-acetyl-D-glucosamine oligomers

The binding of ShigeUa dysenteriae 1 cytotoxin to HeLa cells in culture and to isolated rat liver cell membranes was studied by means of an indirect consumption assay of toxicity from the medium, or by determination of cytotoxicity to the HeLa cell monolayer. Both liver cell membranes and HeLa cells removed toxicity from the medium during incubation, in contrast to WI-38 and Y-1 mouse adrenal tumor cells, both of which neither bound nor were affected by the toxin. Uptake of toxin was directly related to concentration of membranes added, time,and temperature, and indirectly related to the ionic strength of the buffer used. The chemical nature of the membrane receptor was characterized by using three principal approaches: (a) enzymatic sensitivity; (b) competitive inhibition and (c) receptor blockade studies. The receptor was destroyed by proteolytic enzymes, phospholipases (which markedly altered the gross appearance of the membrane preparation) and by lysozyme, but not by a variety of other enzymes. Of 28 carbohydrate and glycoprotein haptens studied, including cholera toxin and ganglioside, only the chitin oligosaccharide lysozyme substrates, per N-acetylated chitotriose, chitotetraose, and chitopentaose were effective competitive inhibitors. Greatest inhibition was found with the trimer, N, N’, N” triacetyl chitotriose. Of three lectins studied as possible receptor blockers, including phytohemagglutinin, concanavalin A, and wheat germ agglutinin, only the latter, which is known to possess specific binding affinity for N, N’, N” triacetyl chitotriose, was able to block toxin uptake. Evidence from all three approaches indicate, therefore, existence of a glycoprotein toxin receptor on mammalian cells, with involvement of oligomeric β1{arrow}4-1inked N-acetyl glucosamine in the receptor. This receptor is clearly distinct from the G(M1) ganglioside thought to be involved in the binding of cholera toxin to the cell membrane of a variety of cell types susceptible to its action.     

Anaerobic transformation of a technical brominated diphenyl ether mixture by super-reduced vitamin B12 and dicyanocobinamide

The anaerobic transformation of the technical octabromo diphenyl ether mixture, DE-79, was investigated by incubation with two super-reduced corrinoids, dicyanocobinamide and cyanocobalamin (vitamin B12). The transformation produced 33 brominated diphenyl ethers (BDEs), 23 of which could be assigned to known structures. Within 1 d, the hepta- to nona-BDEs in DE-79 were almost quantitatively transformed with dicyanocobinamide to lower-brominated homologs. Along with the decrease of high-brominated congeners, concentrations of some tetra- to hexabromo congeners initially increased, followed by a decreasing or constant concentration during longer incubations. Super-reduced cyanocobalamin also was able to transform BDE congeners of DE-79. Whereas the transformation rates of hepta- to nona-BDEs of DE-79 by both corrinoids were comparable, tri- to hexa-BDEs were susceptible to further transformation by super-reduced cyanocobalamin. Incubation of DE-79 with either corrinoid produced significant amounts of BDE 49. Because this congener is found in small quantities in both penta- and octabromo technical BDE mixtures, it may be a suitable indicator for reductive debromination of higher-brominated BDEs. Isolated BDE 196 was incubated as well with super-reduced dicyanocobalamine. After 1 d, 13 BDEs could be detected, with BDE 153, BDE 100, and BDE 99 dominating. After 7 d, only tetra-BDEs or lower-brominated BDEs were detectable. It could be shown that reductive debromination by super-reduced corrinoids is a possible source for lower-brominated BDEs (i.e., BDE 47, BDE 99, BDE 153, and BDE 154). The patterns observed with our bench-scale study design demonstrate that anaerobic transformation in the presence of reducing agents can help to explain the occurrence of environmentally relevant BDE congeners (e.g., BDE 47, BDE 99, and BDE 153).     

Mammography phototimer technique chart

A phototimer technique chart for mammography is presented along with the methodology used to design it. The chart is based on accurate measurement of breast thickness and helps overcome the inability of the phototimer to track as breast thickness varies. In clinical practice, the chart results in the consistent attainment of optimally exposed films and decreased number of retakes.     

Ophthalmomyiasis externa by Musca domestica in a case of orbital metastasis

Infestation of the living tissues of the eye, ocular adnexae or orbit by larvae of flies of the order Diptera is known as ophthalmomyiasis. Ophthalmomyiasis externa is a limited superficial infestation of external ocular structures such as conjunctiva and adnexae. A case of follicular carcinoma thyroid with orbital metastasis presenting as ophthalmomyiasis externa is reported. The patient presented with foul smelling ulcers of the medial and lateral orbital walls of the right eye extending into the lids and nose, teeming with maggots. Computerized Tomography (CT) showed widespread bone destruction with extension into surrounding sinuses. Over 200 maggots were manually removed after immobilisation with turpentine oil instillation. Entomological examination showed it to be a case of accidental myiasis caused by the common housefly Musca domestica. The patient was managed conservatively and the ulcer cavities filled up with healthy granulation tissue. This case is presented on account of its rarity.     

Preliminary in vivo atherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

In this paper, we explore two parameters or strain indices related to plaque deformation during the cardiac cycle, namely, the maximum accumulated axial strain in plaque and the relative lateral shifts between plaque and vessel wall under in vivo clinical ultrasound imaging conditions for possible identification of vulnerable plaque. These strain indices enable differentiation between calcified and lipidic plaque tissue utilizing a new perspective based on the stiffness and mobility of the plaque. In addition, they also provide the ability to distinguish between softer plaques that undergo large deformations during the cardiac cycle when compared to stiffer plaque tissue. Soft plaques that undergo large deformations over the cardiac cycle are more prone to rupture and to release micro-emboli into the cerebral bloodstream. The ability to identify vulnerable plaque, prone to rupture, would significantly enhance the clinical utility of this method for screening patients. We present preliminary in vivo results obtained from ultrasound radio frequency data collected over 16 atherosclerotic plaque patients before these patients undergo a carotid endarterectomy procedure. Our preliminary in vivo results indicate that the maximum accumulated axial strain over a cardiac cycle and the maximum relative lateral shift or displacement of the plaque are useful strain indices that provide differentiation between soft and calcified plaques.