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Supplementary materials detailing the level of background signals present in the Ptolemy instrument during cruise and pre-landing operations

Pancreatic and intestinal growth rates were measured in mice fed on raw soya-bean flour (RSF) for up to 24 weeks. Control animals were fed on standard chow. The effects of RSF on the mouse pancreas resembled that seen in rats, showing hypertrophy with some hyperplasia. A marked increase in small intestinal weight was also found in mice fed on RSF but not in rats fed on this diet. Histological studies showed an increase in both villous and crypt thicknesses in the small intestine from these mice, and DNA, RNA and protein measurements indicated that the increase in intestinal weight was due to hypertrophy and hyperplasia of the mucosal layer. To determine whether the intestinal growth in mice fed on RSF was purely a response to the trypsin inhibitor (TI) component of the diet, pancreatic and intestinal growth rates were also determined in mice fed on the synthetic trypsin inhibitor camostate, at levels of 0·5 or 2 g/kg in rat chow, for periods of 1–8 weeks. Control animals were fed on standard chow. RSF and 0·5 g camostate/kg had similar trypsin inhibitor activities (measured against bovine trypsin), and both caused similar increases in pancreatic weight, DNA, RNA and protein content. However, 0·5 g camostate/kg did not affect small intestinal weight. Chow containing 2 g camostate/kg contained twice as much TI activity as the RSF diet but produced only a small increase in small intestinal weight at 2 and 8 weeks. This intestinal growth was significantly less than that seen with RSF. The present study shows that, in the mouse, RSF or a diet containing camostate in the appropriate dose produces pancreatic growth comparable to that seen in the rat. RSF also causes intestinal growth, but camostate-containing diets have little or no effect on the growth of the intestine.

Pancreatic nodules were produced in rats by either feeding raw soya flour alone or by injection of azaserine plus raw soya flour feeding. The resulting nodules were studied to determine whether there was any functional difference between this tissue and the relatively normal internodular pancreas. Tissue DNA and trypsin content were significantly elevated in nodules compared to the adjacent tissue. With fasting, protein and enzyme content increased significantly and equally in both nodular and internodular tissues. RNA levels fell significantly and the decrease was more pronounced in nodular tissue. The responsiveness of the multinodular pancreas to cholecystokinin was examined by measuring pancreatic secretion basally and in response to cholecystokinin. Both the volume and protein content secreted by the multinodular pancreas were greatly elevated above control levels. When corrected for pancreatic weight, the difference remained significant and appeared to be due to increased basal secretion by the nodular pancreas. These studies demonstrate that azaserine-raw soya flour induced nodules are functionally efficient. Furthermore, the secretory response to cholecystokinin of these nodules is equal to or higher than that of normal tissue.

Nuclei of pancreatic cells were isolated by trypsin-detergent digestion of fresh tissue and stained with propidium iodide, and nuclear DNA was measured by flow cytometry. Samples were isolated from mice fed either chow or raw soya flour (RSF) for periods ranging from 1 day to 48 weeks, beginning at 4 weeks of age. In chow-fed mice, the pancreas contained about 80% diploid (2N) and 20% tetraploid (4N) cells at the start of the study, but tetraploidy gradually increased to about 40% 2 weeks later (6 weeks of age) and remained at this level from that time onwards. Low levels of octaploid nuclei (8N) were also present in some animals after 2 weeks. In RSF-fed mice, about 20% tetraploid nuclei were also present for 1 and 2 days after starting RSF, but by 4 days tetraploidy had increased significantly to 40% and by 14 days had further increased to 50%. This level was significantly higher than that seen in chow-fed animals and was maintained for up to 48 weeks. Significantly higher numbers of octaploid nuclei were also present in the RSF-fed animals. In both chow- and RSF-fed mice, most cells were mononuclear, averaging 70% in chow-fed and 64% in RSF-fed animals. This difference was significant. This study shows that the mouse pancreas differs from the rat pancreas in the absence of a large population of binucleate acinar cells and the presence of considerable nuclear tetraploidy. Raw soya flour feeding leads to significant changes in these features, but in this species these changes do not appear to predispose to neoplasia.

The solvatochromic behaviour of a number of pentacyano-ferrates (II), [FeII(CN)5L] n-, is described, for solutions in H2O-alcohol, -Me2CO and -DMSO mixtures. The strong dependence of solvent sensitivity on the nature of the ligand L is particularly fully documented for H2OMeOH mixtures (0–100% MeOH). The piezochromic behaviour of seven pentacyanoferrates(II) has been established, in aqueous solution. The connection between piezochromism and solvatochromism is detailed, and the solvatochromic results discussed in terms of (preferential) solvation.

1. This study examines the influence of starvation on intestinal CCK content and pancreatic growth. Intestinal CCK content was determined by measuring the CCK-like activity using an in vitro gall-bladder bio-assay. Starvation for up to 72 hr causes a parallel fall in intestinal CCK content and pancreatic DNA synthesis. Since there was no significant decrease in liver DNA synthesis, the effect of starvation was probably not simply a consequence of malnutrition. Furthermore there was little effect of starvation on pancreatic protein and DNA content, suggesting that pancreatic cell turnover is particularly sensitive to changes in dietary stimulation. 2. With refeeding after starvation CCK-like activity in intestinal extracts gradually increased, approaching non-fasting levels 72 hr after refeeding. Pancreatic DNA synthesis also returned to non-fasting levels after feeding but this rose faster than the intestinal CCK content. 3. Pentagastrin treatment prevented the atrophy of both the pancreas and the gastrointestinal tract with starvation without influencing the fall in intestinal CCK-like activity. This suggests that the control of CCK-containing cells is different from that of the surrounding intestinal parenchyma. 4. The effect of starvation was also studied in antrectomized rats. Antrectomy alone did not reduce pancreatic DNA synthesis although DNA synthesis of the small intestine was significantly reduced. When antrectomized rats were starved pancreatic DNA synthesis fell to the same degree as was found in unoperated animals. The pancreatic atrophy was also accompanied by a drop in intestinal CCK content. Starvation of antrectomized rats, however, did not further depress the already greatly reduced plasma gastrin concentration.

An unemulsified oil test meal containing aqueous- and oil-phase markers (PEG and 3H labelled triether) was fed to control and bile fistula rats. PEG moved ahead of the lipid phase in all groups, and was of limited value as a marker for the test meal. Triether was an excellent marker for studies of gastric emptying. An unexpectedly high correlation was seen between the triether and the test meal and its digestion products in the intestine. The results suggest that triether is a valid marker for following the movement of lipid through the bowel under the conditions of this study. Triether/fat ratios indicated that fat absorption occurred largely from the upper small bowel in control animals and from the lower small bowel in the absence of bile. Bile diversion resulted in more rapid gastric emptying initially, but very slow gastric emptying of the last part of the oil test meal. Intestinal transit of test meal or either marker was not significantly affected by bile diversion. No evidence for a direct effect of bile diversion on gastrointestinal motility was found.

Involution of the enlarged pancreas was studied in rats changed from a diet of raw soya flour (RSF) to a normal diet of cubes. After feeding RSF for 4 or 12 wk pancreatic weight, DNA, RNA, and protein were all significantly greater than in control animals fed cubes continuously. When these animals were changed to a cube diet, pancreatic DNA and RNA returned to control values within 48 h, while pancreatic weight and protein reverted to control values within 7 days of the change in diet. The morphological changes seen in the pancreas during involution indicate that cell death occurred by the process of apoptosis. Increased cell death during involution was seen as a rapid increase in the incidence of apoptotic bodies (AB) located in the cytoplasm of intact acinar cells and macrophages. These AB's contained condensed fragments of cytoplasm, nuclear, or a combination of these remnants, which were derived from the acinar cell. The increase in apoptosis after withdrawal of the RSF diet was probably in response to the withdrawal of the trophic influence, cholecystokinin.

We have reviewed the growth-promoting and carcinogenic effects of feeding raw soya flour to rats. If the raw soya flour-containing diets are fed for more than a year, about 10% of the animals develop pancreatic cancer. In addition, feeding raw soya flour markedly potentiates the action of even subthreshold amounts of pancreatic carcinogens. The raw soya flour therefore acts as a potent promoter, as well as a weak carcinogen. In view of this promotion, the rat fed raw soya flour is a sensitive model for screening pancreatic carcinogens. It is not known whether the human pancreas responds to dietary trypsin inhibitors in a manner similar to the rat. However, in view of the use of soya-based products in human nutrition--especially in infant foods--we urge that the effect of all soya-based products intended for human use be tested on the rat pancreas in long-term feeding studies, combined with subthreshold doses of azaserine to highlight any promoting activity of the product. It seems probable that if a product exerts no effect on the rat pancreas, the human pancreas will also be spared from noxious effects.

Pancreatic acinar cell turnover was studied after a 48-h fast and in rats fed raw soya flour (RSF) for up to 28 days. Feeding RSF for 2 days resulted in a significant increase in pancreatic weight and RNA content while protein was increased by the 4th day compared with rats fasted for 48 h. RSF also resulted in a significant increase in RNA by the 4th day and weight and protein by the 7th day compared with rats fed heated soya flour (HSF). This pancreatic hypertrophy was maintained for the rest of the study period. Two days after starting RSF, pancreatic DNA synthesis, measured bythe rate of incorporation of [3H]thymidine into pancreatic DNA, had increased sixfold compared with that in animals fedHSF but returned to control values again by the 4th day on the diet. Autoradiography showed that this increase in DNA synthesis occurred in both acinar and duct cells, with turnover in acinar cells preceding that in duct cells. A second moregradual rise in DNA synthesis was seen from the 7th to 28th day. This peak in DNA synthesis was associated with an increased total pancreatic DNA content and occurred predominately in duct cells with a smaller contribution from acinar cells. Histological studies of the pancreas during the 1st wk showed cell damage and tissue necrosis, possibly due to exposure to high levels of cholecystokinin released by RSF. The first peak in DNA synthesis may be a regenerative response to this damage. The second more delayed peak appears to be hyperplasia in response to a trophic stimulus, again possibly mediated by cholecystokinin.

We studied the effect of raw soya flour (RSF) given as a single gavage or for long-term periods on pancreatic blood flow. These effects were compared with the response to treatment with cholecystokinin (CCK) since it has been suggested that RSF feeding releases CCK. In acute experiments total pancreatic blood flow was significantly increased after infusion of CCK (60 Ivy dog units X kg-1 X h-1) and after gavage with preparations of RSF or heated soya flour (HSF). When expressed as flow per 100 g pancreatic weight, the greatest increase was seen after gavage with RSF. In separate chronic studies, total pancreatic blood flow was significantly increased in rats fed RSF for 4 wk compared with rats fed HSF, but because of pancreatic enlargement in rats fed RSF flow per 100 g pancreatic weight was similar in the two groups. When rats fed RSF for 4 wk were changed to standard rat cubes for 48 h before study, pancreatic blood flow (ml/min and ml X min-1 X 100 g pancreas-1) and total pancreatic DNA decreased significantly compared with rats fed RSF continuously. However, when CCK was infused intravenously during the 48-h period on cubes, pancreatic blood flow and DNA remained significantly increased and were not significantly different from values in rats fed RSF continuously. These results show that the effects of RSF feeding and CCK treatment on pancreatic growth and blood flow are similar and are consistent with the postulated role of CCK as the trophic hormone released by RSF feeding.

The effect of long-term dietary modification on pancreatic exocrine function in rats has been investigated by examining responses to cholecystokinin-pancreozymin stimulation, using a method of direct pancreatic duct cannulation. Residual pancreatic enzyme activity remaining in the whole pancreas following stimulation was also measured. After 6 months of dietary modification, changes in the pancreatic secretions of high-protein- or high-fat-fed animals were similar to those reported in short-term studies in which elevation of trypsin and lipase activity occurred in the pancreas. However, between 6 and 9 months, both volume and amylase activity of pancreatic secretions decreased in animals fed a high-protein diet. At 6 and 9 months, animals fed a high-carbohydrate diet had increased amounts of amylase and decreased trypsin in both pancreatic secretion and homogenate, similar to short-term changes previously reported. High-carbohydrate-fed animals had decreased lipase activity in pancreatic secretions, but lipase activity in pancreatic homogenates was increased, similar to levels found in animals fed a high-fat diet.

1. The effect on pancreatic digestive enzyme levels of fasting and changes from a diet containing trypsin inhibitor (raw soya-bean flour, RSF) to diets free of trypsin inhibitor (heated soya-bean flour, HSF, or commercial rat chow) was studied in rats for up to 7 d.2. In RSF-fed rats killed without fasting, enzyme levels were low, but after fasting for 24 h before killing there was a marked increase in all enzyme levels. Histological studies showed that pancreatic acinar cells from RSF-fed rats killed without fasting were devoid of zymogen granules, but following a 24 h fast there was a marked accumulation of zymogen granules which extend into the basal cytoplasm. Fasting either produced no change or a fall in enzyme levels in rats fasted after feeding HSF or chow continuously.3. If animals fed on RSF were changed to HSF and either fed or fasted for 24 h up to the time of killing there was an increase in amylase (EC3. 2. 1. 1), trypsin (EC3. 4. 21. 4), lipase (triacylglycerol lipase;EC3. 1. 1. 3) and protein 1 d after the change, followed by a fall over the next 6 d to levels similar to those seen in rats fed on HSF continuously.4. Animals changed from RSF to chow showed similar effects as far as trypsin, lipase and protein were concerned, but amylase rose, to reach the level seen in rats fed on chow continuously (about ten times that seen in soya-bean-fed rats), after 2 d.5. These results suggest that in the rats fed on RSF, pancreatic enzyme synthesis is rapid but secretion is equally rapid and intracellular enzyme levels are low. When these animals are fasted or changed to a diet free of trypsin inhibitor the rate of secretion falls but the high rate of synthesis continues for at least 24 h and enzymes accumulate in the pancreas. In studies of pancreatic enzyme levels in rats fed on trypsin inhibitor the extent of fasting before killing the animal is therefore an important variable. Such animals should probably not be fasted before study.

McGuinness EE, Morgan RGH, Wormsley KG. Trophic effects on the pancreas of trypsin and bile salt deficiency in the small-intestine lumen. Scand J Gastroenterol 1985, 20(suppl 112), 64–67.The effect of trypsin inhibitor-containing diets was studied in rats, mice, and hamsters for 30 weeks. in rats, pancreatic weight, DNA, RNA, and protein increased in response to a diet of raw soya flour (containing trypsin inhibitor). in mice, pancreatic weight, DNA, RNA and protein content increased with the same diet. Only rats developed micro- and macro-nodules. in rats, longer treatment with raw soya flour resulted in further growth in the pancreas, with ultimate development of adenomas and carcinomas of the acinar pancreas. the pancreatic changes were reversible up to 6 months of feeding the raw soya diet, but thereafter became irreversible. Pancreatic growth, similar to that produced by trypsin inhibitor, was also produced by cholestyramine, perhaps as a result of its bile salt-binding properties. We conclude that r...

Rats were fed raw and heated soya flour for up to 2 years. The rats fed raw soya flour all developed pancreatic hypertrophy and hyperplastic and adenomatous nodules. Four of 26 rats fed raw soya flour continuously and 1 of 5 rats fed raw soya flour for 2 days each week developed pancreatic cancer. Preheating the soya flour seemed to protect against the pancreatic hyperplastic and neoplastic changes.

Fat absorption, stomach emptying and intestinal motility were studied in rats in which the bile had been diverted to the terminal ileum or to the urinary bladder 7–10 days previously. Diversion of bile to the ileum should interfere little with the enterohepatic circulation and thus allow a normal blood and tissue level of bile salts. Diversion to the bladder should produce a total bile fistula. In both experimental groups, fat recovery from the gut lumen after 48 hr. starvation was greater than in the controls. Diversion of bile to the bladder markedly depressed the absorption of a test meal containing coconut oil over a 3-hr. test period. Diversion to the ileum, however, had no such effect. These results are consistent with an important intracellular, rather than intraluminal, role of bile salts. Stomach emptying and movement of a marker substance through the small intestine were normal in the group with bile diverted to the ileum. Stomach emptying was more rapid than normal and movement through the small intestine was delayed in the group with bile diverted to the bladder. Probably the effects on absorption of fat and gut motility are not interdependent.

Flat braids partially soldered together with a soft nonsuperconducting alloy have superior electrical stability and mechanical properties as compared to braids made from fully insulated superconducting wires. Eddy currents induced by a changing field, however, may cause undesirable field shape changes and power loss in magnets. An analysis of these eddy currents for the case of constant rate of change of field is presented, and comparisons made with observed field distortions or power loss in two magnets.

The motility of the gastric antrum was recorded with a saline manometer in normal rats and in rats in which the bile and sometimes also the pancreatic juice had been diverted to the exterior. The inhibitory effects of a variety of substances infused into the duodenum were tested. There was an inhibitory response to 50 per cent glucose, 0·2N HCl or 20 per cent ethanol, which was not altered by diversion of bile or both bile and pancreatic juice. The inhibitory action of triglyceride was lost within one hour of diversion of bile, but could be restored by adding bile salts or Tween 80 to the infused fat. Neither bile salts nor Tween 80 restored the response to triglyceride in the absence of both pancreatic juice and bile. Oleic acid was an active inhibitor of antral motility in all groups, but was more effective when emulsified. Bile salts alone had no effect on gastric motility in the doses used when infused intraduodenally or intravenously. These results suggest that the material causing the inhibition of gastric motility after a fatty meal is not the triglycerides, but the free fatty acids liberated and emulsified under the combined action of bile and pancreatic juice.

A simplified model is used to study the response to a slowly changing uniform magnetic field of a wire consisting of fine filaments of superconductor embedded in a normal metal matrix, the entire wire being twisted about its axis. Expressions for the critical twist pitch, the power loss in the normal metal, and the time constant are obtained.

Emulsified and unemulsified fat was infused intraduodenally at a steady rate in unanaesthetized rats with lymph fistulhe. The output of esterified fat in the lymph reached a steady state which was considered to mirror fat absorption from the lumen. In animals which also had bile fistulae the effect of addition or removal of sodium taurocholate was measured. Unemulsified olive oil or oleic acid and mono-olein sol was poorly absorbed in the absence of bile. Emulsified olive oil was better, but still incompletely, absorbed. In all these cases the addition of sodium taurocholate increased the absorption to that found in control animals with normal bile flow. Emulsified oleic acid was as well absorbed in bile fistula animals as in controls and the return or removal of taurocholate did not affect the output of esterified fat in the lymph. These results do not support a defect in epithelial re-esterification of fatty acids in the absence of bile.

The involvement of membrane phospholipids in the utilization of transferrin-bound iron by reticulocytes was investigated using [59Fe]- and [125I]-labelled transferrin and rabbit reticulocytes which had been incubated with phospholipase A. Transferrin and iron uptake and release were all inhibited by phospholipase A which produced a marked decrease in the relative abundance of phosphatidylcholine and phosphatidylethanolamine and equivalent increases in their lyso-compounds in the reticulocyte plasma membrane. There was a close correlation between the iron uptake rate and the rate and amount of transferrin uptake and the amount of the lysophospholipids in the membrane. Incubation of the cells with exogenous lysophosphatidylethanolamine or lysophosphatidylcholine also produced inhibition of iron and transferrin uptake. The reduced uptake produced by phospholipase A could be reversed if the lyso-compounds were removed by fatty acid-free bovine serum albumin or by reincubation in medium 199. Treatment with phospholipase A was shown to increase the amount of transferrin bound by specific receptors on the reticulocyte membrane but to inhibit the entry of transferrin into the cells. The present investigation provides evidence that the phospholipid composition of the cell membrane influences the interaction of transferrin with its receptors, the processes of endocytosis and exocytosis whereby transferrin enters and leaves the cells, and the mechanism by which iron is mobilized between its binding to transferrin and incorporation into heme. In addition, the results indicate that phosphatidylethanolamine is present in the outer half of the lipid bilayer of reticulocyte membrane.

Di(2-hydroxypropyl)nitrosamine was administered to rats fed raw or heated (control) soya flour diets. The group fed raw soya flour developed hyperplastic and adenomatous pancreatic nodules and pancreatic adenocarcinomata. We conclude that a diet of raw soya flour augments the carcinogenicity of pancreatic carcinogens in the rat.

Coaxial cable conductors in the form of helical tape windings have been proposed in order to make Nb3Sn cables which have flexibility and the ability to take up thermal contraction. For ac power transmission the axial magnetic fields which occur in a simple helical construction produce a number of undesirable consequences. It has been shown that these problems can be avoided by using double layer windings of opposite helicity, with 45° as the optimum helix angle. However, smaller values than this are desirable for mechanical reasons, and this paper extends the theory to include pitch angles < 45°. Measurements on short cable models are shown to be in reasonable agreement with calculation. The effect of current flow around the superconductor tape edges, which occurs in helical windings, is analyzed and it is shown that appreciable ac loss can arise if laminated tape with non‐superconductive edges is used indiscriminately.

We have previously shown that rats fed raw soya flour (RSF) for more than four months develop hyperplastic foci of pancreatic acinar cells, which undergo malignant change if feeding RSF is continued throughout the life of the animals. The tendency to undergo malignant change is augmented by the additional use of a genotoxic carcinogen such as azaserine. The present study has sought to examine the reversibility of the focal neoplastic change in the pancreas. Rats fed RSF for 24 weeks and then given a diet not containing soya flour (NSC) had a normal pancreas when killed after 60 weeks of study. When RSF was fed for only 36 weeks, however, some of the rats developed pancreatic cancer even though the diet had been switched to NSC. Similarly, while azaserine in the dose used in the present study does not produce pancreatic cancer in our strain of Wistar rats, coincident administration of RSF for 12 weeks (but not for six weeks) resulted in progression to pancreatic adenoma. Although change from RSF to NSC after 30 weeks resulted in rapid reduction in pancreatic weight and content of RNA, neoplastic foci persisted and became frankly malignant. We conclude that phenotypic reversion to normal of the RSF diet- and azaserine-treated rat pancreas is only possible if RSF alone is fed continuously for not more than about 24 weeks or six weeks if the rats have been exposed to a pancreatic initiating carcinogen.

Intraperitoneal di(2-hydroxypropyl)-Nitrosamine (DHPN) caused a high incidence of oesophageal squamous carcinoma in male Wistar rats, particularly in rats killed 11 or more months after the start of injections. No control rats (injected intraperitoneally with saline) developed an oesophageal neoplasms. Histopathologically, the tumours were moderately well differentiated. Histochemical studies showed minor increases in mucin staining and mast cell population and a marked increase in bacteria in tumour-bearing oesophaguses. Electron microscopy showed the tumours to be similar to, but to differ in some respects from squamous carcinomas at other sites in humans. The possible implications of this work for human disease are twofold. It could provide a model for further study of aspects of oesophageal carcinoma and it serves to remind us that all potential oesophageal carcinogens need not act during swallowing.

1. Pancreatic growth was measured in rats by changes in pancreatic weight, nucleic acid content and protein content after feeding diets of heated soya-bean flour (HSF), raw soya-bean flour (RSF), 200 g raw soya-bean flour+800 g heated soya-bean flour/kg (80 HSF) and 400 g raw soya-bean flour+600 g heated soya-bean flour/kg (60 HSF) for periodsup to 36 weeks. Control rats of comparable age to soya-bean flour-fed rats were continuedon rat cubes during the 36-week study.2. Cube-fed rats remained significantly heavier than rats fed on soya-bean flour diets. Analysis of variance showed rats fed on HSF were significantly heavier than RSF-fed rats and rats fed on 80 HSF significantly heavier than those fed on 60 RSF.3. Pancreatic indices in HSF-fed rats were similar to comparable control rats.4. Hypertrophy was found in rats fed on the RSF-containing diets with the extent of enlargement corresponding to the RSF content. Hyperplasia was also found in rats fed on RSFand 60 HSF.5. The greatest pancreatic growth was seen in RSF-fed rats with all the indices peaking at 8 weeks followed by a decline and then a rise again at 36 weeks.6. The fall in pancreatic indices in rats fed on RSF for 12 and 24 weeks is most likely an effect of general malnutrition due to the multiple deficiences in amino acids which occur in animals fed on RSF. The rise at 36 weeks may reflect increased body growth or the beginning of adenornatous changes.

Raw soya flour (RSF) feeding to rats produces pancreatic hypertrophy and hyperplasia, and, if sufficiently prolonged, the spontaneous development of pancreatic neoplasms and the potentiation of pancreatic carcinogens. With continuous exposure to RSF the threshold dose for pancreatic growth is approximately 20% RSF, but the threshold for the other effects has not been defined. If 100% RSF is fed for less than 24 weeks continuously the effects on the pancreas are completely reversible, but feeding for longer than this leads to irreversible progression to pancreatic adenoma and carcinoma over the next 50–70 weeks. Repeated alternation of the diet between 100% RSF and rat chow for prolonged periods leads to effects on the pancreas at least as marked as those seen with continuous RSF feeding. This occurs with RSF feeding for periods as short as 2 days out of 7. The effects seen in the rat must be applied to human nutrition with caution, but it is suggested that infants fed soya based milk substitutes and fad dieters who frequently radically alter dietary composition may be more susceptible to spontaneous or carcinogen-induced pancreatic neoplasms.

Pancreatic acinar cells from rats 5 to 658 days (94 weeks) of age were isolated by enzymatic dissociation and stained with the DNA specific fluorochrome Hoechst 33258. The nuclear DNA content and the incidence of binucleation were estimated in these cells. Total pancreatic weight, RNA, protein and DNA, and the incorporation of 3H-thymidine into pancreatic acinar cell DNA were also estimated in similar animals as measures of pancreatic growth. From 5 to 17 days after birth, 95% of the cells were mononucleate diploid and 5% were binucleate diploid; but during the period of rapid pancreatic growth over the following 39 days, acinar cells became increasingly binucleate. By 56 days after birth, 64% of cells were binucleate with a diploid DNA content per nucleus; and the incidence of binucleation then remained constant. At 28 days of age, 4% of mononucleate cells were tetraploid, increasing to 6% at 658 days of age. At this time 3% of binucleate cells contained dual tetraploid nuclei. There is thus a rapid development towards diploid binucleate acinar cells in the growing, postnatal pancreas; and in the adult pancreas a small proportion of these cells develop tetraploid nuclei.

Summary Feeding a diet of raw soya flour, which contains a trypsin inhibitor, results in pancreatic hypertrophy and hyperplasia, and when this diet is withdrawn rapid involution ensues. This study examines whether cells produced during the hyperplastic response to raw soya four (RSF) are selectively destroyed during involution following the withdrawal of this diet. Six week old male Wistar rats were fed RSF. At 7, 9 and 12 d after commencing the diet, during the period of maximum cell proliferation, rats were injected with 0.5 μ/Ci/g body weight of tritiated thymidine. The rats were continued on this diet for a further 16d. By 1 mth pancreatic DNA, RNA, protein, weight and the specific activity of pancreatic DNA were all significantly greater in rats fed RSF, compared to control rats fed a standard diet. When rats fed RSF were changed to a diet free of trypsin inhibitor for 7 d, pancreatic DNA, RNA, protein and weight returned to control values, however the specific activity of DNA remained unchanged from the RSF value. This report suggests that cell death involves cells produced before and during the hyperplastic response to RSF, since there is no change in the specific activity of the organ after involution.

Summary Rats were treated with raw soya flour to produce pancreatic hypertrophy and also received azaserine, a pancreatic carcinogen. The combined treatment resulted in the development of large numbers of hyperplastic nodules in the acinar tissue of the rat pancreas. We conclude that the pancreas of the rat stimulated to proliferate by raw soya flour provides a sensitive model for detecting and studying pancreatic carcinogens.

Conceptually, one phase of a proposed three-phase power transmission system consists of a pair of coaxial tubes or pipes, with superconductor on the outside of the inner pipe and on the inside of the outer pipe. Although rigid versions of this concept have been under development for nearly a decade there are strong economic and technical reasons to develop a flexible form of cable. In this construction the conductor and insulation are wound as concentric helices, thus permitting many of the advantages of flexibility to be reaped at the expense of several new problems not encountered in plain concentric cylindrical designs. In this paper the electrical complications arising from helical current paths are discussed. The practical manifestations are primarily heating of the normal metal used in the cable and undesirable voltages appearing on the outer conductor.

Fat absorption was studied in normal and bile fistula rats using test meals of corn oil containing radioactively labelled triolein. Two types of test meal were used, which would produce differently labelled monoglyceride and fatty acid under the action of pancreatic lipase. Triolein containing 3H labelled oleic acid in the 1 and 3 positions and 14C labelled oleic acid in the 2 position was fed to normal and bile fistula rats with and without lymph fistulae. Short term pancreatic lipolysis of this triolein produced 3H labelled fatty acid and 14C labelled 2-monoolein. Fat balance studies, Cori type experiments and the recovery of label in the lymph showed that in bile fistula rats 3H was absorbed in excess of 14C during the first few hr after feeding. In contrast, in lymph fistula rats with a normal bile flow 14C was absorbed in excess of 3H except in the earliest sample. These results indicate that after digestion triglyceride is absorbed mainly as fatty acid in the bile fistula rat, but as a mixture of fatty acid and monoglyceride in the normal animal. Analysis of lymph lipids confirmed that the mechanism of absorption is different in the bile fistula and normal animals. A mixture of triolein labelled with 3H in the glycerol moiety and triolein labelled with 14C in the fatty acid moieties was also used as a marker in corn oil test meals fed to lymph fistula rats with and without bile diversion. In bile fistula rats the early lymph samples contained more 3H than 14C, but from 6 hr onward 14C predominated, and overall more 14C than 3H was recovered in the lymph. It seems probable that the early high recovery of 3H was due to the incorporation of free glycerol into lymph lipids in these animals. The overall recovery of 14C in excess of 3H is consistent with the concept that triglyceride is absorbed chiefly as fatty acid in the absence of bile. In animals with a normal bile flow 14C was absorbed in excess of 3H throughout the recovery period. It is concluded that the mechanism of fat absorption in the bile fistula rat is not the same as it is in the presence of bile. Possibly fatty acid may be absorbed as soaps in the absence of bile, but no mechanism for the absorption of intact monoglyceride by these animals can be suggested.