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The biology of the helminth parasite Schistosoma mansoni is closely integrated with that of its mammalian host. SmRK1, a divergent type I transforming growth factor-beta (TGF-beta) receptor of unknown ligand specificity, was previously identified as a candidate for a receptor that allows schistosomes to respond to host-derived growth factors. The TGF-beta family includes activin, bone morphogenetic proteins (BMPs), and TGF-beta, all of which can play crucial roles in metazoan development. The downstream signaling protein of receptors that respond to TGF-beta and activin is Smad2, whereas the receptors that respond to BMPs signal via Smad1. When a constitutively active mutant of SmRK1 was overexpressed with either schistosome Smad1 (SmSmad1) or SmSmad2, a receptor-dependent modulation of SmSmad phosphorylation and luciferase reporter activity occurred only with SmSmad2. To evaluate potential ligand activators of SmRK1, a chimeric receptor containing the extracellular domain of SmRK1 joined to the intracellular domain of the human type I TGF-beta receptor was used. The chimeric receptor bound radiolabeled TGF-beta and could activate a luciferase reporter gene in response to both TGF-beta 1 and TGF-beta 3 but not BMP7. Confirmatory results were obtained using full-length SmRK1. These experiments implicate TGF-beta as a ligand for SmRK1 and as a potential host-derived regulator of parasite growth and development.

Dry cotton hay or seed samples from plants grown in 0.5 ppm 14MC‐DDT, ‐dieldrin, ‐endrin, and ‐heptachlor treated soils were subjected to exhaustive Soxhlet extraction with chloroform/methanol (CM), hexane/acetone (HA), hexane/acetone/methanol (HAM), or hexane/acetone/ methanol/water (HAMW). Extracts further were fractionated by selective elution from Florisil columns and the 14C‐insecticide residues determined. The relative extracting power of the solvents was HAMW>HAM=CM>HA; this applied to all insecticides except DDT, whose residue was too low for reliable comparison. No solution removed all the 14C‐residue from plant tissue. HAM afforded greater simplicity and less time in cleanup compared to CM. One dieldrin degradation product, three endrin degradation products, and three heptachlor degradation products, which includes heptachlor epoxide, were believed extracted from cotton hay with HAMW.

Soybeans (Glycine max[L.] Merr., var. ‘Clark’) and cotton (Gossypium hirsutumL., var. ‘Acala 4‐42’) were grown in Lakeland sandy loam and Hagerstown silty clay loam soils treated with 0.5 ppm 14C‐DDT, ‐dieldrin, ‐endrin, and ‐heptachlor. Periodically, the top portion of one plant per pot was harvested and assayed for insecticide. At maturity, the seed and cotton lint were separated from the hay and assayed separately. Two methods of assay were used, i.e., gas‐liquid chromatography and 14C counting by liquid scintillation. Total 14C‐residue concentrations in soybeans for all four insecticides increased linearly during active growth stages, whereas highest 14C‐residues in cotton were found at the first harvest. No parent DDT or heptachlor was detected in any of the soybean or cotton samples by gas‐liquid chromatographic determination, though small amounts of unidentified DDT residues were detected by liquid‐scintillaton counting of plant extracts of both species. Heptachlor epoxide was present in soybeans at less than 0.1 ppm in hay and less than 0.04 ppm in seed. No heptachlor epoxide was detected in cotton, but unidentified 14C‐heptachlor residues were present at an equivalent of less than 0.065 ppm. Dieldrin residues ranged as high as 0.3 ppm in soybean hay and 0.09 ppm in seed. Endrin residues ranged as high as 0.5 ppm in soybean hay and 0.1 ppm in seed, though actual endrin was less than these values. Dieldrin and endrin residues in cotton hay were below 0.03 ppm and none was detected in seed or lint. The use of 14C‐labeled insecticides demonstrated that all 14C‐residues were not removed from plants. Furthermore, discrepencies between gas‐liquid chromatography and 14C determinations of plant extracts indicated endrin degradation products were present. Soil type influenced the plant uptake of these insecticides, especially endrin. Plants grown in the Lakeland s1 soil concentrated greater insecticide amounts than the Hagerstown sicl, presumably because of the lower organic matter content of the Lakeland soil. Cotton removed considerably more insecticides from soils than soybeans because of their greater mass. Based on these results, cropping would not be an efficient method of removing chlorinated insecticides from contaminated soils.

A Lakeland sandy loam was treated at three depths with 14Cendrin insecticide in which one crop of soybeans (Glycine max L., Merr.) was grown. After harvesting the soybeans, the soil was sectioned and assayed for endrin residues. At least three and possibly five transformation products of endrin occurred. Two products were identified as 1,8,9,9,10,11‐hexachloropentacyclo [6.3.0.12,5.03,7.06,10] dodecan‐12‐one (endrin delta ketone) and 1,8,9,9,10, 11‐hexachlorohexacyclo [6.3.0.12,5.03,7.06,10.011,12] dodecan‐12‐ol (endrin alcohol). A third product may have been 1,8,9,9,10,11‐hexachloropentacyclo [6.3.0.02,11.03,7.06,10] undecan‐12‐carboxaldehyde (endrin aldehyde). Endrin transformation appeared to increase with soil depth. In an extremely acid soil (pH 4.2) endrin transformed to some endrin ketone and probably endrin aldehyde during treatment of the dry soil, but not of moist soil. Acid or base treatment of endrin and several endrin isomers indicated that endrin was stable under basic conditions and that endrin alcohol and endrin aldehyde (presumably) were stable in all treatments tested, except the base treatment at 100C for endrin aldehyde.

The influence of DDT, dieldrin, and endrin placement depth in soil on their plant uptake and translocation was investigated. In a greenhouse study, soybeans were grown for 75 days in soil columns containing a 1‐cm layer of 20 ppm 14C‐insecticide‐treated soil placed at either 1–2, 16–17, or 31–32 cm deep (depths A, B, and C, respectively) within the column. Radioactivity in root sections showed that all three insecticides were absorbed and translocated both basipetally and acropetally. Maximum mean residues in roots (DDT, 14.9; dieldrin, 29.1; endrin, 29.5 ppm air‐dry basis) always resulted from placement at depth A. Maximum DDT (<0.01 ppm), dieldrin (0.68 ppm), and endrin (1.20 ppm) residues in total aerial organs resulted from depth A also. Residues decreased strikingly as placement depth increased. The B depth resulted in mean aerial residues amounting to 6.8% (dieldrin) or 15.0% (endrin) of those resulting from A, while C depth resulted in mean aerial residues of only 0.6% (dieldrin) or 6.7% (endrin) of those from depth A. Only trace amounts of DDT residues resulted from depths B and C. Since uptake was affected by insecticide placement depth, prediction of crop residues based on soil residues must include a consideration of residue location in soil. Results suggest that deep plowing of insecticide‐containing soil could be used to reduce residues in crop plants.

Soybeans were grown in specially constructed pots to determine the amount of residue contamination in plant tops from 20 ppm surface or subsurface soil‐applied 14C‐labeled p,p'‐DDT, dieldrin, endrin, or heptachlor. Regardless of the insecticide treatment, plant tops were contaminated by both root sorption and foliar sorption of vapors emanating from the soil. Root sorption was the major source of contamination by dieldrin, endrin, and heptachlor, though vapor sorption of dieldrin was nearly as great. Foliar contamination by vapor sorption of DDT residues was nearly seven times greater than for root sorption. Foliar contamination from vapor sorption of residues from all four insecticides was near the same order of magnitude, about 6.5 ppm plant dry weight, whereas contamination from root sorption from endrin was 38, heptachlor 21, dieldrin 11, and DDT 1 ppm. Plant parts were assayed by several methods. Although residue concentrations were different for each insecticide, both the apparent plant degradation and mobility of the insecticide, or degradation products, were: DDT ≥ heptachlor > endrin > dieldrin where root sorption was the source of residue. One heptachlor degradation product, in addition to heptachlor epoxide, two endrin degradation products, and p,p'‐DDE and p,p'‐DDD were found.

Only 8% of cancers of the pancreas, duodenum, and common bile ducts, in patients admitted over a 14-year period, qualified for curative resections. To date, among 275 cases, there is but one five-year survivor. In spite of these disappointments, a nihilistic approach to pancreaticoduodenal malignancy is not warranted. Patients receiving palliative procedures survived longer than those without surgery, and pancreaticoduodenectomy generally afforded a longer survival than patients undergoing palliative procedures. Among the patients with resectable lesions of the ampulla of Vater, there were no postoperative deaths even though all but two were in the seventh decade. These patients represent survivals so far from 9 to 74 months. The increasing incidence of cancer of the pancreas makes apparent an increased need for the training of the surgeon well versed in the performance of pancreatic resection.