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21 (26 mg, 39%) were separated by preparative TLC (C) and identified by comparison with authentic materials, prepared according to Le Men et al.26 X-ray Structure Determination. (A) Zwitterion 7a Hydrate (XR-1). Single crystals of XR-1 suitable for X-ray diffraction study were grown from a saturated MeOH solution. The structure was solved by direct methods (program multan so): the "best" E-map allowed to localize 27 heavy atoms over a total of 32. The remaining heavy atoms were located on a difference Fourier map. After isotropic refinement of heavy atoms, all hydrogen atoms, with the exclusion of those of solvation water, were located on a difference Fourier map. Hydrogen atoms at C(18) and C(25) gave problems in the least-squares process and then were fixed in calculated positions. Hydrogen atoms of solvated water were not clearly localized, because of the high thermal internal motion or the disorder of the same.(B) Isoxazolidine 8b Hydrobromide (XR-2). Single crystals of XR-2 were obtained by diffusion of diisopropyl ether into a saturated MeOH solution of 8b-HBr. The structure was solved

Syrian hamsters present a unique species for induction of pancreatic tumors that in many aspects resemble human pancreatic cancer. The specific response of Syrian hamsters, in contrast to may other rodents, for development of pancreatic ductal (ductular) tumors is not yet known. All pancreatic carcinogens thus far tested show certain common features. They are all nitrosamines that possess or can be metabolized to compounds with 2-oxopropyl- or 2-hydroxypropyl substituents. All but one, N-nitroso-methyl(2-oxopropyl)amine, occur or metabolize to nitrosamines with the ability to cyclize and form structures resembling glucose. Hence it is suggested that this cyclic structure may be responsible for the pancreatic carcinogenicity of these nitrosamines, as has been proposed for the pancreatotropic effect of streptozotocin. It is also of further interest that one pancreatic ductal (ductular) carcinogen, N-nitroso-2-methoxy-2,6-dimethylmorpholine, which possesses a totally cyclic structure, acts, like streptozotocin, as beta-cell cytotoxic and diabetogenic when given in a high single dose. Modification of pancreatic tumor induction has been demonstrated by specific procedures. A high fat diet significantly increases both the incidence and number of induced cancers. Methods for early diagnosis and therapy are being developed and their significance and applicabilities for clinical use will be of major importance. Compared with the other most common types of human cancer, pancreatic cancer has extraordinary characteristics, which make the disease one of the most mysterious of maladies. Consequently, pancreatic cancer represents a serious international problem and requires urgent resolution, especially with regard to its etiology, early diagnosis, prevention, and therapy.

In 110 well-trained participants of a 1000-km running competition lasting for 20 days hematological parameters, iron metabolism, and their respective changes during the race were investigated. Thirty-nine men and 11 women were accustomed to wholesome vegetarian food (lacto-ovovegetarian), 52 men and 8 women consumed a conventional western diet. In each group 50% of the runners finished the race. Before the competition started red blood cell count, hematocrit, and hemoglobin were on average below the values observed in the normal population in all groups. Both male and female runners consuming the wholesome diet showed significantly lower ferritin values than those on a western diet. During the first days of the competition hemolysis occurred leading to increased serum concentrations of bilirubin and iron and decreased haptoglobin levels. Hb concentrations showed a constant decrease during the race. Serum ferritin concentration rose about twofold within the first days and then decreased again without reaching pre-race levels. Serum iron concentrations showed a significant decrease between days 3 and 6. Iron loss was caused by hematuria (25% of all urines tested), gastrointestinal blood loss (10% of all stool specimens tested), and by sweating (4.5 micrograms iron/dl sweat). Our results suggest that especially in female long-distance runners it may be difficult to supply sufficient quantities of iron with the diet.