颠茄类生物碱的毛细管气相色谱和色—质联用分析

本文用毛细管气相色谱和气相色谱-质量选择检测器分析颠茄生物碱类(莨菪碱、东莨菪碱、山莨菪碱和樟柳碱)的研究。对颠茄生物碱与不同硅烷化试剂、反应能力、反应时间以及反应温度作了探索。结果表明,MSTFA是最好的硅烷化试剂。文内给出了这些生物碱的原型和硅烷化衍生物的保留值和它们的特征性碎片离子。这些数据有助于该类生物碱的鉴定。方法已初步应用于这些生物碱在生物合成中的转化研究。此外,还讨论了颠茄生物碱类TMS衍生化的优点。     

Duodenal mucosal histology and histochemistry in active, treated and healed duodenal ulcer: Correlation with duodenal prostaglandin E2 production

We investigated whether impaired duodenal mucosal prostaglandin E₂ (PGE₂) production previously observed in duodenal ulcer (DU) was a primary pathophysiological abnormality or secondary to mucosal architectural changes that accompany ulceration. One hundred patients were studied: at endoscopy, paired duodenal biopsies were taken in patients with normal endoscopies and from the ulcer edge or scar and background mucosa in active or healed DU. One of the pair of biopsies was used to estimate PGE₂ synthesis ability, the other was processed for histology and histochemistry. The following features graded: goblet cell numbers and staining with Periodic acid-Schiff reagent (PAS), epithelial staining with PAS, villous atrophy, columnar cell height, inflammatory cell infiltrate and micro-erosions and gastric metaplasia taken as a whole. Patients were found to have normal endoscopy (n= 31), active untreated DU (n= 20), active DU on treatment with either cimetidine or ranitidine (n= 13), healed DU on maintenance treatment (n= 27) and healed DU off treatment (n= 9). Active duodenal ulceration was found to be associated with decreased numbers of goblet cells, loss and blunting of villi, increased columnar cell height, increased epithelial cell PAS staining and with gastric metaplasia. After healing, only villous blunting remained. These changes were present, but less marked, at sites removed from the ulcer and were not apparent in the patient groups with healed ulcers. A strong correlation between overall gastric metaplasia and epithelial cell PAS staining and the reduced ability to synthesize PGE₂ (P < 0.001) was only apparent when biopsies from all patients were grouped together, but not within individual patient subgroups. There was no consistent correlation between PGE₂ generation and individual parameters of pathological change in the duodenum. We conclude that, although inflammatory and mucosal changes may contribute, the evidence suggests that the impaired PGE₂ generation in DU disease is, to a large extent, independent of histological and histochemical features.     

Chordoma: role of radiation therapy

The treatment of 21 patients with a diagnosis of chordoma seen over a 20-year period is described. The 13 men and eight women (ratio 1.6:1) ranged in age from 7 to 82 years (average, 50 years). Eleven chordomas arose from the clivus; the others originated in the sacral region (three patients), thoracic spine (one), cervical spine (three), and lumbar spine (three). Primary treatment consisted of surgery, reserving radiation therapy for recurrence in the majority of patients. Radiation doses, delivered with megavoltage equipment, ranged between 5,000 cGy delivered over 5 weeks and 6,600 cGy over 6 1/2 weeks. Irradiation produced significant tumor control, with remission of symptoms from 1 to 6 years. The combination of high-dose radiation therapy and complete or subtotal surgical resection offers the best chance for prolonged survival in this group of patients.     

Noninvasive differentiation of tumors with use of localized H-1 MR spectroscopy in vivo: initial experience in patients with cerebral tumors

A recently developed method for image-selected localized hydrogen-1 magnetic resonance (MR) spectroscopy was assessed in the differential diagnosis of nine primary and secondary cerebral tumors, including four gliomas, two meningiomas, one neurilemoma, one arachnoid cyst, and one metastasis of breast cancer. Well-resolved H-1 MR spectra of these tumors were obtained in vivo with a conventional 1.5-T whole-body MR imaging system. All tumor spectra were remarkably different from spectra from normal brain tissue. Spectra obtained from different tumors exhibited reproducible differences, while histologically similar tumors yielded characteristic spectra with only minor differences. The observed spectral alterations reflect variations in concentrations and relaxation times of the H-1 MR sensitive pool of free (mobile) metabolites within the tissues. In most cases, the concentrations of N-acetyl-aspartate and creatine/phosphocreatine are reduced below detectability, whereas choline-containing compounds are generally enhanced. The spectral differences between the tumors are mainly due to the differing concentrations of lipids, lactic acid, and carbohydrates. Localized H-1 MR spectroscopy may become an important clinical tool for the differentiation of tumors as well as for therapeutic control.