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Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that plays a significant role in mitotic progression and cellular responses to DNA damage. While traditionally viewed as a tumor suppressor, inhibition of PP2A has recently come to attention as a novel therapeutic means of driving senescent cancer cells into mitosis and promoting cell death via mitotic catastrophe. These findings have been corroborated in numerous studies utilizing naturally produced compounds that selectively inhibit PP2A. To overcome the known human toxicities associated with these compounds, a water-soluble small molecule inhibitor, LB100, was recently developed to competitively inhibit the PP2A protein. This review summarizes the pre-clinical studies to date that have demonstrated the anti-cancer activity of LB100 via its chemo- and radio-sensitizing properties. These studies demonstrate the tremendous therapeutic potential of LB100 in a variety of cancer types. The results of an ongoing phase 1 trial are eagerly anticipated.

1. Mucin histochemistry is markedly altered in the stomach in intestinal-type adenocarcinoma. To increase understanding of these changes we have examined the content and distribution of carbohydrate in mucus glycopolypeptides isolated from non-malignant antrum, and from the uninvolved gastric mucosa and tumour site of patients with this disease. 2. The content of carbohydrate declined by 12.6% (P = 0.02) in mucus glycopolypeptides from uninvolved gastric mucosa when compared with those from non-malignant antrum, and by a further 25.4% (P < 0.001) in mucus glycopolypeptides from the tumour site. The first of these changes was accompanied by a significant decrease in the number of carbohydrate chains/1000 amino acid residues, and a significant increase in the number of monosaccharide units in each carbohydrate chain. The second of these changes was accompanied by significant decreases in both the number of carbohydrate chains/1000 amino acid residues, and in the number of monosaccharide units in each carbohydrate chain. 3. The number of sulphated monosaccharide units/100 carbohydrate chains increased from a mean of 7.2 in mucus glycopolypeptides from non-malignant antrum to a mean of 27.2 (P < 0.001) in preparations from uninvolved gastric mucosa and 22.7 (P < 0.001) in preparations from the tumour site. 4. Evidence is presented that these structural changes to mucus glycopolypeptides from the malignant stomach are due to an abnormal mucin biosynthesis by metaplastic goblet cells and/or immature gastric-type mucous cells within the uninvolved mucosa, and immature mucous cells at the tumour site.

Purified human urogastrone was given by intravenous infusion to 12 normal volunteer subjects and measurements made of gastric acid, pepsin and intrinsic factor secretion, and of plasma gastrin concentration. Clinical, haematological, and biochemical screening tests were made throughout the period of study. Urogastrone inhibited acid and intrinsic factor secretion whether stimulated by pentagastrin, histamine, or insulin, but had a much less marked effect on gastric pepsin output. Plasma gastrin levels did not alter significantly. Limited dose-response studies showed that 0-25 mug urogastrone kg--1 hr--1 resulted in inhibition of acid output of 80% and was not associated with clinical side-effects. No significant alteration in any of the haematological or biochemical measurements was observed in any of the subjects.

A one-hour infusion of 0.25 micrograms/kg urogastrone administered to seven patients with duodenal ulceration resulted in significant reduction of basal acid secretion (p less than 0.05) but was without significant effect on basal pepsin and intrinsic factor secretion or on serum gastrin concentration. In another group of five patients with duodenal ulceration a one-hour infusion of urogastrone was given on five successive days. On day 1 and 5 urogastrone was administered after establishing a plateau response to intravenous pentagastrin 1.2 micrograms/kg/h. A mean reduction of 65% in acid output during the urogastrtone infusion was seen on day 1 and this was maintained during the next hour. On day 5 the pentagastrin-stimulated acid output was less than on day 1 and a further significant decrease was noted after urogastrone. Pepsin and intrinsic factor output were also significantly inhibited. There was no change in fasting serum gastrin or urogastrone concentration.

A total of 153 patients (124 male and 29 female) with uncomplicated chronic duodenal ulceration were studied in a prospective, randomized trial of proximal gastric vagotomy (PGV) and truncal vagotomy and pyloroplasty (TVP), conducted in four Manchester hospitals. Of these, 137 patients have now been followed up for 2·5 to 5·5 (mean 4·1) yr. There have been 15 (21 per cent) recurrent ulcers following PGV compared with 5 (7·5 per cent) after TVP (P < 0·05). A satisfactory functional result was obtained in 82 per cent of patients after TVP compared with 73 per cent following PGV and there was little difference between the groups with regard to the incidence of dumping, heartburn and vomiting. There was significantly more diarrhoea following TVP (13 per cent) compared to PGV (1·4 per cent) but this represented only a minor clinical problem.

The effects of human urogastrone (0-25 mug. per kg. per hour intravenously) in four male patients with proven Zollinger-Ellison syndrome (z.e.s.) and in four healthy control subjects have been studied. After urogastrone in z.e.s. patients gastric acid volume and concentration decreased and basal acid output was reduced by 50-82%; the concentrations of intrinsic factor and pepsin in gastric juice increased by 60-300%; and peak plasma-gastrin concentration increased by 127-164% of basal concentration. A significant negative correlation between increase in plasma-gastrin concentration and decrease in acid output was observed (r=-0-72, P less than 0-01). Ulcer pain was relieved 30-60 minutes after the beginning of urogastrone infusion. These results suggest that urogastrone can inhibit the endogenously stimulated acid hypersecretion in z.e.s.

The 99Tcm clearance technique is shown to be a useful method of assessing gastric function. It is easily carried out and is relatively non-toxic–the dose of isotope could be reduced to 100 μCi or less without sacrificing the accuracy of the investigation. Although the results are preliminary and the number of cases investigated so far is small, they suggest that the measurement of pertechnetate clearance is directly related to gastric mucosal blood flow; it is a use ful parameter of gastric function and may well prove to be a more accurate discriminant in cases of peptic ulceration than the conventional measurement of gastric acid secretion.

Three patients with dyspeptic symptoms who were being treated with the H2-receptor blocking drug, cimetidine, were later found to have gastric carcinoma. It was not possible to determine whether the association was fortuitous, whether the drug had masked the neoplastic change, or whether it was involved in some other way. Repeated clinical and endoscopic evaluation is essential in patients on this treatment for any length of time.

Using Fordtran's technique but substituting the meat extract Oxo for the steak meal we investigated gastric acid secretion in eight control subjects and nine patients with chronic duodenal ulcer. Intragastric titration was performed using a double lumen tube measuring the pH in the stomach every three minutes and adjusting it to 5.5 throughout the test by infusing 0.3-M sodium bicarbonate. On a separate day a pentagastrin test was performed using a conventional gastric aspiration technique. In the eight control subjects the mean acid output after pentagastrin was 13.7 +/- 2.1 (SEM) mmol/h, whereas the mean hourly acid output measured by intragastric titration was 20.1 +/- 3.1. The greater response to Oxo than to pentagastrin in the controls (deltaAO = + 46%) was significant (P less than 0.01). This is in contrast with our duodenal ulcer patients whose mean hourly acid outputs were 22.7 +/- 4.4 and 23.0 +/- 4.4 mmol/h in response to pentagastrin and Oxo respectively (r = 0.95). The findings, while clearly at variance with those of Fordtran and Walsh (1973), are more in keeping with the concept of increased endogenous secretory drive in duodenal ulcer patients compared to normal subjects.

Summary In a prospective, randomized trial, 76 patients with duodenal ulceration treated by truncal vagotomy and pyloroplasty were compared with 77 patients who underwent highly selective vagotomy. A total of 149 patients was followed up for from 1 to 4 years, the average follow-up period being 2.6 years. There was no operative mortality and no significant difference in postoperative morbidity between the two groups. The incidence of recurrent ulceration was greater after highly selective vagotomy, but this difference was not statistically significant. The clinical results were comparable in each group, and although the incidence of diarrhoea and dumping was greater after vagotomy and pyloroplasty, this difference was not statistically significant.

Forty-four general surgical patients were included in a prospective, randomized double-blind controlled trial of ascorbic acid (500 mg b.d.) or placebo for 7 days before operation. This was to test the hypothesis that vitamin C may reduce the instance of deep venous thrombosis postoperatively. Venous blood samples were taken before entering the trial, just immediately before surgery, on the day of operation and on three further occasions at 3-day intervals postoperatively for leucocyte ascorbic acid concentration (LAC). Venous thrombosis was diagnosed using the 125I-fibrinogen test and the leg scans interpreted by Roberts' criteria. There was no significant difference in the incidence of DVT between the treatment and placebo groups. In those with DVT (n = 23) the mean LAC on the day of operation was not significantly different from that in those without DTV. However, on the sixth and ninth postoperative days LAC levels were significantly lower in the DVT group. These results suggest that the administration of ascorbic acid preoperatively does not reduce the incidence of DVT, but a striking decrease in the LAC levels in the DVT patients in in keeping with the hypothesis that the initial event in the pathogenesis of DVT is adherence of leucocytes to the venous endothelium.

Achalasia of the cardia is rare in childhood. The occurrence of this condition in a nine year old girl, in whom treatment by a modified Heller’s operation has relieved the symptoms, is described. The