1. A new method of purification of renin is described. This method employs the following procedures: ethanol precipitation; saline extraction; precipitation of renin with 40% ammonium sulphate; precipitation of impurities with 3% ammonium sulphate at pH2.5; chromatography on DEAE-cellulose and CM-Sephadex; gel filtration on Sephadex G-100 (both normal and superfine grade); finally, starch-gel electrophoresis. 2. The final renin preparation had a specific activity 10(4) times that of the initial saline extract. 3. A single band of stained protein corresponding to the renin activity was present on starch-gel electrophoresis in the final step and a single precipitin line was obtained to this material with rabbit anti-(pig renin) serum. 4. Double diffusion in agar with rabbit anti-(pig renin) serum showed one major precipitin line, probably due to renin-anti-renin complex, and in addition two minor components.

Animals↗

PubMed1965

Purification of pig renin.

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Animals↗

PubMedDate not supplied

Photodynamic therapy using 5-aminolaevulinic acid for oesophageal adenocarcinoma associated with Barrett's metaplasia.

Photodynamic therapy (PDT) is a novel technique for local endoscopic treatment of gastrointestinal neoplasia. Current photosensitisers for PDT may cause prolonged skin phototoxicity. 5-Aminolaevulinic acid (ALA), a precursor of the photosensitiser protoporphyrin IX (PpIX), is more acceptable because of its short half-life and preferential accumulation in mucosa and mucosal tumour. We have treated 12 patients, median age 73 years (range 55-88) with oesophageal adenocarcinoma arising from Barrett's metaplasia (two carcinomas-in-situ, grade 0; 10 carcinomas, grade 1-11A based on endoluminal ultrasound in two and CT scanning in 10 patients). ALA (60 and 75 mg/kg body weight) was given orally in two or five equally divided doses. The PpIX distribution in stomach, normal oesophagus, Barrett's mucosa and carcinoma was measured by quantitative fluorescence photometry. PDT was performed using laser light (630 nm) delivered via a cylindrical diffuser 4-6 h after the first dose of ALA. The patients received one to four sessions of PDT. PpIX accumulation in the mucosa was two to three times that in the lamina propria. The differential distribution between carcinomatous and normal oesophageal mucosa was less marked (carcinoma:normal mucosa ratio = 1.4). Higher doses of ALA increased PpIX accumulation in all tissues but did not increase the differential PpIX distribution between tumour and normal oesophageal mucosa. After PDT using ALA (ALA/PDT), all mucosa showed superficial white necrotic changes and the histology confirmed fibrinoid necrosis. One patient with carcinoma-in-situ had the tumour eradicated after one treatment with no recurrence at 28 months. Another patient with a small T1 tumour required four ALA/PDT treatments, and died of other disease after 36 months. There was no evidence of recurrence. The tumour bulk in the other carcinomas was not significantly reduced. ALA/PDT has a potential for the eradication of small tumours but careful patient selection with endoluminal ultrasound is needed when using ALA/PDT to treat oesophageal cancer.

Adenocarcinoma↗