Is an amphiphilic region responsible for the haemolytic activity of Bacillus thuringiensis toxin?†

The amino acid sequence of the 27 kDa protein responsible for the haemolytic activity of Bacillus thuringiensis subsp. israelensis toxin has been analysed by secondary structure prediction, helical wheel/net diagrams and molecular mechanics calculations. We found that segment 116–126 presumably forms a strongly amphiphilic α-helix. This is supported by the findings that the synthesized segment 116-126 (a) has a significant α-helical content in water, and (b) displays an in vitro haemolytic activity comparable to that of bee venom peptide melittin. As segment 116-126 is present in the haemolyzing, but not present in the non-haemolyzing proteins from B. thuringiensis toxins, we suggest that this segment is responsible for the lytic potential of the B. thuringiensis subsp. israelensis protein.     

尿中多种蛋白同化激素药物的GC/MS分析及代谢研究

本文对国际奥委会禁用的19种蛋白同化激素进行了人体服药试验;从尿中富集提取所排泄的这类激素,对它们在人体内的代谢情况进行研究,弄清了各药物的主要代谢途径;获得了药物原型及其主要代谢物的GC,MS数据;在此基础上,建立了系统分析和检测尿中蛋白同化激素的最优化方法。     

Transforming Growth Factor-β Induced Protein, βIG-H3, is Present in Degraded Form and Altered Localization in Lattice Corneal Dystrophy Type I

Lattice corneal dystrophy type I (LCDI) is an inherited autosomal dominant local amyloidosis, restricted to the corneal stroma. Comparison of electrophoretic profiles of normal and dystrophic corneas revealed a 42 kD protein, which was present only in dystrophic corneas. TheN-terminal sequence of this protein showed identity to transforming growth factor-β induced gene product (βIG-H3). A polyclonal antiserum was raised in chicken against a synthetic peptide identical to theN-terminal portion of βIG-H3. On immunoblots, the antiserum stained the 42 kD band, and also a 68 kD band corresponding to the reported molecular weight of the intact βIG-H3. In normal corneas, only the 68 kD band was present. Immunohistologically, the antiserum stained corneal subepithelial regions, including subepithelial deposits, in dystrophic corneas. In normal corneas, the staining was observed only in the epithelium. These results may reflect the role of βIG-H3 in extracellular matrix construction and/or amyloid formation.     

Pharmacokin?tics of intravenous and oral cyclophosphamide in the presence of methotrexate and fluorouracil

Cyclophosphamide was administered to 12 breast cancer patients in combination with methotrexate and fluorouracil. Doses prescribed were cyclophosphamide 75 mg/m², methotrexate 30 mg/m² and fluorouracil 500 mg/m² (per square meter body surface). Cyclophosphamide was administered intravenously and orally in aqueous solutions and in tablets in a randomized cross-over trial. Methotrexate and fluorouracil were administered intravenously, methotrexate was given first and then fluorouracil. Assays of cyclophosphamide in blood plasma were performed by capillary gas chromatography. Data of mean bioavailability of cyclophosphamide administered by tablets were suggestive of sufficient absorption. In 2 patients, however, a lower bioavailability of cyclophosphamide was demonstrated. Intra-individual differences in the terminal slope of the plasma decay curves after intravenous and oral administration in some patients decreased the calculated bioavailability of cyclophosphamide, if these values were included in the calculation of cyclophosphamide bioavailability. Compared with the administration of the solutions peak times, lag-times and mean absorption times of cyclophosphamide given in tablets were markedly prolonged. It is concluded that interactions between cyclophosphamide and methotrexate and/or fluorouracil after oral dosing as tablets are different from interactions observed after intravenous administration of cyclophosphamide.     

Thyroglossal duct carcinoma

PURPOSE OF REVIEW: The purpose of this paper is to review the presentation and management of thyroglossal duct carcinoma. RECENT FINDINGS: Recent articles have analyzed the value of preoperative investigation and have addressed some of the controversies in the management of such tumors; in particular, the optimal surgical management of the thyroid gland, as well as optimal management of lymph node metastases, the role of thyroid suppression therapy, and radioactive iodine therapy. SUMMARY: Thyroglossal duct carcinoma is uncommon, occurring in approximately 1% of all thyroglossal duct cysts. It is often diagnosed incidentally after surgical excision. Ninety-four percent of carcinomas are of thyroid origin, with most being papillary in nature, and 6% are of squamous cell origin. Incidentally discovered, well-differentiated thyroid carcinoma of the thyroglossal duct, in the presence of a clinically and radiologically normal thyroid gland, can be managed adequately by the Sistrunk operation. Those patients with more advanced disease require more aggressive treatment. This may include a total thyroidectomy with or without neck dissection in addition to the Sistrunk operation, followed by radioactive iodine therapy and thyroid-stimulating hormone suppression. The prognosis is generally excellent with adequately treated disease.