Nuclease activity of 1,10-phenanthroline-copper: sequence-specific targeting.

The nuclease activity of 1,10-phenanthroline-copper ion can be targeted to specific DNA sequences by attachment of the ligand to the 5' end of complementary deoxyoligonucleotides via a phosphoramidate linkage. To synthesize the adduct, the phosphorimidazolide of the deoxyoligonucleotide is prepared using a water-soluble carbodiimide and is then coupled to 5-glycylamido-1,10-phenanthroline. After hybridization to the target DNA, sequence-specific cleavage is observed upon the addition of cupric ion and 3-mercaptopropionic acid. Two methods of assaying the cutting of the operator sequence of the lac operon have been employed using the oligonucleotide 5'-AATTGTTATCCGCTCACAATT-3' representing sequence positions 21-1 of the template strand. In the first, the single-stranded DNA of the phage M13mp8 was the target, and cuts were detected using a primer-extension assay. In the second, the substrate was an EcoRI fragment 3' labeled in the nontemplate strand. After denaturation and reannealing to the oligonucleotide-1,10-phenanthroline adduct, cupric ion and 3-mercaptopropionic acid were added, and the products were analyzed directly on a sequencing gel. With the phenanthroline moiety attached to position 21 of the oligonucleotide carrier, cutting was observed at positions 20-25 using both assays.     

环孢菌素A阻断人HL－60抗药性细胞于G_1期而诱导敏感细胞凋亡

进一步研究了抗三尖杉酯碱的ＨＬ－６０细胞（ＨＲ２０）抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明，环孢菌素Ａ（ＣｓＡ）２０，１０μｇ·ｍｌ￣（－１）诱导ＨＬ－６０细胞发生凋亡，而阻断ＨＲ２０细胞于Ｇ＿１期，就不能诱导细胞发生凋亡。低浓度的ＣｓＡ明显增加柔红霉素在ＨＲ２０细胞内的积聚，其逆转抗药性作用与阻断细胞周期运行无关。ＣｓＡ１０μｇ·ｍｌ￣（－１）处理ＨＲ２０细胞，可引起５０ｋＤａ的蛋白质高度磷酸化。结果提示：环孢菌素Ａ阻断抗三尖杉酯碱的ＨＬ－６０细胞于Ｇ＿１期，而诱导敏感的ＨＬ－６０细胞发生凋亡，其阻断作用与抗药性无关     

Microsurgical anatomy of VII and VIII cranial nerves and related arteries in the cerebellopontine angle

Summary The relationships of VII and VIII cranial nerves and related arteries are reviewed in 26 preparations by microdissection techniques. These vessels may be grouped in large (AICA, PICA), medium (LA, SA, CSA, RPI) and small calibre (vasa nervorum, radicullar and medullar branches). The importance of these structures in acoustic neuroma surgery, vestibular neurectomy and cross-compression syndromes is discussed. Vascular loops and elongated arteries are normal structures present at birth.This work was supported by a grant from the AJ Roemmers Foundation     

Osteosarcomatosis

A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized.     

Endoscopic retrograde stenting for allograft hydronephrosis

BACKGROUND AND OBJECTIVES: Ureteral obstruction occurs in 2% to 10% of all renal transplant recipients. Antegrade endourologic intervention has been the gold standard of therapy but carries significant morbidity. This study was designed to investigate the feasibility of retrograde stenting of these difficult ureters and to determine whether it can be performed with minimal morbidity without general or regional anesthesia. METHODS: Ninety-seven consecutive patients were found to have renal allograft hydronephrosis by ultrasonography, between August 1993 and March 1997. Of these, 61 (63%) had confirmation of obstruction by MAG-3 imaging, with equivocal results in 25 (26%). The remaining 11 patients had a rising creatinine concentration despite Foley catheter drainage. All patients had retrograde stenting attempted under local anesthesia followed by intravenous sedation if necessary. If stent placement was unsuccessful, the procedure was repeated under regional or general anesthesia. RESULTS: A total of 85 patients (88%) were managed successfully with retrograde stenting. Of these procedures, 24 (28%) were performed under local anesthesia alone, while 57 (67%) required both local anesthesia and intravenous sedation. Only 4 patients (5%) required general anesthesia. No patient suffered any morbidity associated with retrograde stenting. Of the 12 patients in whom retrograde stenting failed, 2 had renal allograft rupture and 10 had ureteral necrosis at surgical exploration. CONCLUSIONS: Retrograde stenting of the hydronephrotic renal allograft can be achieved with a high success rate and minimal morbidity, usually without general or regional anesthesia. If the ureter cannot be managed in a retrograde fashion, a high index of suspicion for a serious allograft complication should exist.