Benign rectal strictures managed with transanal resection--a novel application for transanal endoscopic microsurgery.

OBJECTIVE: Six cases of management of rectal strictures by transanal endoscopic microsurgery (TEM) are described. METHOD: Patients are placed in the lithotomy - Trendelenburg position and the stricture is resected from 4-8 o'clock through the entire thickness of the fibrosis. The upper resection edge is mobilized including all layers of the rectal wall and the defect is sutured along the circumference. RESULTS: Satisfactory anatomical and functional long-term results were obtained in 5 of 6 patients. CONCLUSION: TEM resection of benign strictures is feasible in some patients and should be tested in a randomized study against known procedures.

Good clinical practice and audits for dual X-ray absorptiometry and X-ray imaging laboratories and quality assurance centers involved in clinical drug trials, private practice, and research.

Good Clinical Practice (GCP) guidelines, with an emphasis on quality and validation of processes and data, must be applied to the use of imaging in clinical drug development. All participants, including the sponsor, principal investigator, site staff, quality assurance centers, and contract research organizations, must be cognizant of the need for application of these principles to their activities related to the imaging programs. This article discusses the various aspects of GCP as they need to be applied to the use of dual X-ray absorptiometry (DXA) for bone densitometry and X-rays for vertebral fracture assessment in clinical trials for osteoporosis, as well as research and private practice settings. The theory of proper audit conduct to verify clinical trial data is presented.

Preparative, analytical and fluorescence spectroscopic studies of sulphonated aluminium phthalocyanine photosensitizers.

Fluorescence spectroscopic studies were carried out on aluminium phthalocyanine with defined numbers (mono, di, tri and tetra) of sulphonate groups. Selective sulphonation was achieved using one of two synthetic methods to prepare a mixture of components which were separated using reverse-phase liquid chromatography. Fluorescence lifetimes were measured in methanol and buffer solution using time-correlated single-photon counting with picosecond laser excitation; the lifetime shows little variation with the number of sulphonate groups. Using steady state excitation, fluorescence quantum yields were determined for the tetrasulphonated component (phi F = 0.51) and, for comparison, unsulphonated aluminium phthalocyanine.

Effect of sulfonation on the cell and tissue distribution of the photosensitizer aluminum phthalocyanine.

Aluminum sulfonated phthalocyanine has potential as a suitable photosensitizer for use in the photodynamic therapy of cancer. In the present study, cellular uptake and retention of the individual mono-, di-, tri-, and tetrasulfonated derivatives (AlS1-4Pc) were examined in tissue culture and in normal and neoplastic tissue of tumor-bearing mice. Uptake and retention of the various derivatives by cells in tissue culture correlated inversely with the degree of sulfonation. Accordingly, Colo 26 cells in monolayer culture, 24 h after addition of 10 microM of appropriate photosensitizer, had accumulated approximately 25-fold more AlS1Pc than AlS3Pc and retained this species longer than more sulfonated derivatives. In contrast to these in vitro results, it was found that Colo 26 growing s.c. in BALB/c mice accumulated photosensitizer to a greater extent when the degree of sulfonation increased, such that A1S4Pc greater than AlS3Pc greater than AlS2Pc greater than AlS1Pc. By 24-48 h after the i.v. injection of 0.1 ml 2.27 mM solution of individual photosensitizer, the relative ratios of tumor:adjacent tissue varied from greater than 10:1 to greater than 2:1, showing that selective tumor uptake may be affected profoundly by the composition of the phthalocyanine compound. The livers and spleens of both normal and tumor-bearing mice, unlike other normal tissue, took up the sulfonated derivatives in an order that provided a mirror image of that observed in neoplastic tissue. These complex in vivo distribution and retention characteristics appear to be a consequence of relative hydrophilicity/hydrophobicity properties of the sulfonated species and indicate the extent to which these characteristics may influence photosensitizer distribution and accumulation.

Cell uptake, distribution and response to aluminium chloro sulphonated phthalocyanine, a potential anti-tumour photosensitizer.

The uptake, retention and effects of aluminium chloro sulphonated phthalocyanine (AlSPc) were measured in two cell lines, UV-2237 a murine fibrosarcoma and the non-tumorigenic NIH/3T3 fibroblast line. The behaviour of cells treated with AlSPc was compared with that of those treated with haematoporphyrin derivative (HpD), a photosensitizer often used in photodynamic therapy (PDT) of cancer. AlSPc absorbs light strongly in the red region, is taken up by cells in a dose dependent fashion and is retained in vitro over a period of days (5 days after exposure greater than 40% remains cell-associated versus less than 25% of HpD). Additionally AlSPc was less cytotoxic to cells, maintained in darkness or exposed to room light, compared to HpD (100% viability versus 0% viability 3 days after 60 min exposure to room light). However red light (approximately 600-700 nm) caused greater toxicity in AlSPc-treated cells (100%) than in similarly exposed HpD-treated cells (less than 60%). No significant differences were detected between the responses of the fibrosarcoma and the fibroblast cell lines. These characteristics of AlSPc suggest that it may prove to be a useful photosensitizer for PDT of cancer and this possibility is discussed.