This study determined the incidence of prostate adenocarcinoma following long-term treatment of NBL and Sprague-Dawley rats with estradiol-17 beta or diethylstilbestrol (DES) plus testosterone and it defined the origin of these tumors. NBL and Sprague-Dawley rats were treated with two Silastic tubing implants (i.d. 1.6 mm, o.d. 3.2 mm) containing a 2 cm long filling of testosterone and one implant containing a 1 cm long filling of estradiol-17 beta or DES. Control animals received empty implants. Treated animals were killed when moribund and controls were killed at 91 (NBL) or 75 (Sprague-Dawley) weeks after initiation of treatment and accessory sex glands were sampled for histopathological examination of multiple step sections. Prostatic adenocarcinoma occurred in 100% of NBL rats after treatment with estradiol-17 beta or DES plus testosterone for 44 and 59 weeks (group means) respectively. Adenocarcinoma incidences were lower in Sprague-Dawley rats. The adenocarcinomas were small, microscopic, invasive tumors and they were spatially closely associated with the periurethral ducts of the dorsal, lateral and/or anterior (= coagulating gland) prostate, but never with the ducts of the ventral lobe and seminal vesicles. One adenocarcinoma was of uncertain origin. Duct-acinar dysplastic lesions occurred in the periphery of the dorsal and lateral prostate of all hormone-treated NBL and many Sprague-Dawley rats, but did not appear to give rise to carcinoma. Although some adenocarcinomas were contiguous with dysplastic ducts of the peripheral dorsolateral prostate, the main mass of these neoplasms was located in the periurethral area. Also, most adenocarcinomas were only connected with the periurethral ducts, in which atypical hyperplasia occurred following hormone treatment for 36 weeks or longer. Thus atypical hyperplasia of the periurethral prostate ducts, but not peripheral duct-acinar dysplasia, appeared to be the likely precursor of the induced carcinomas. Testosterone plus DES, but not estradiol-17 beta, induced marked dysplasia-like lesions in the acini of the ventral prostate of all NBL and many Sprague-Dawley rats. These lesions had progressed to carcinoma in situ (or adenoma) in 46% of NBL rats.

Evaluation of alfalfa (Medicago sativa L.) cultivar persistence normally requires at least 3 yr of testing in stressful environments. Fall growth score sometimes has been used to predict winter survival in the absence of long‐term tests. Our objectives were to evaluate the effect of seeding‐year cutting stress on alfalfa cultivar winter injury and plant survival in several Minnesota environments (locations), and to associate winter injury with cultivar fall growth score. Seeding‐year cutting schedules consisted of harvesting at intervals of 24, 30, 35, and 45 d at each of five site‐years. The locations were Lamberton in southwest, Waseca in southeast, Morris in west central, and Rosemount (2 yr) in east central Minnesota. Average alfalfa stands across cutting schedules were 93, 72, 46, and 55% in the year following seeding at Lamberton, Waseca, Morris, and Rosemount, respectively. No differences in winter injury due to cutting schedules occurred at Lamberton because of sufficient winter snow cover. At the other locations, cultivar differences in winter injury were least for the 45‐d schedule. The 24‐, 30‐, or 35‐d cutting schedules produced severe winter injury that differentiated cultivars at Morris, Waseca, and Rosemount. The most fall‐dormant cuitivar, Rambler, generally had the least winter injury, whereas nondormant ‘Nitro’ had the most winter injury. Fall growth score was correlated with winter survival in stressful environments and explained ≈45% of the variation in winter injury, spring stands, or yields for the 24.d cutting schedule treatment. Winter survival of alfalfa for the 35‐ and 45‐d cutting schedules in the most stressful environment, Morris, explained 42% of the variation in long‐term cultivar winter survival, while fall growth score explained 51%. An index combining seeding‐year cutting stress results with fall growth score was a better predictor of long‐term cultivar winter survival than seeding‐year results alone. Alfalfa winter survival is a complex trait that is difficult to predict.

A field study was conducted in an area of enhanced, natural radioactivity to assess the soil to edible vegetable concentration ratios (CR = concentration in dry vegetable/concentration in dry soil) of 232Th, 230Th, 226Ra, 228Ra, and the light rare earth elements (REE's) La, Ce and Nd. Twenty-nine soil and 42 vegetable samples consisting of relatively equal numbers of seven varieties were obtained from 11 farms on the Pocos de Caldas Plateau in the state of Minas Gerais, Brazil. This region is the site of a major natural analogue study to assess the mobilization and retardation processes affecting Th and the REE's at the Morro do Ferro ore body and U series radionuclides at a nearby open pit U mine. Thorium (IV) serves as a chemical analogue for quadrivalent Pu and the light REE's (III) as chemical analogues for trivalent Am and Cm. The geometric mean CR's (all times 10(-4] decreased as 228Ra (148) greater than 226Ra (76) greater than La (5.4) greater than Nd (3.0) = Ce (2.6) greater than 232Th (0.6), or simply as M (II) greater than M (III) greater than M (IV). These differences may reflect the relative availability of these metals for plant uptake. Significant differences were found in the CR's (for any given analyte) among many of the vegetables sampled. The CR's for the different analytes were also highly correlated. The reasons for the correlations in CR's seen among elements with such diverse chemistries as Ra-REE or Ra-Th are not clear but are apparently related to the essential mineral requirements or mineral status of the different vegetables sampled. This conclusion is based on the significant correlations obtained between the Ca content of the dried vegetables and the CR's for all of the elements studied.

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