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Low serum vitamin B-12 concentrations after gastric bypass (GB) surgery for obesity were observed in 11 of 28 patients without detectable impairment of crystalline vitamin B-12 absorption. This was observed in 2 of 19 patients with vertical banded gastroplasty (VBG). In contrast, protein-bound vitamin B-12 absorption was markedly impaired, as demonstrated in eight of these patients after GB (n = 7) and VBG (n = 1). Correction of this impaired absorption occurred when protein-bound vitamin B-12 was incubated with an enzyme mixture before consumption. Simultaneous ingestion of the enzyme mixture with protein-bound vitamin B-12 did not improve absorption of the vitamin. In a separate experiment, 10 patients with a normal result from the Schilling test failed to correct low serum vitamin B-12 concentrations with a quantity of oral crystalline vitamin B-12 equal to the recommended dietary allowance of 2 micrograms, taken twice daily for 3 mo. Serum total homocysteine values declined during this interval. An oral daily dose of 350 micrograms crystalline vitamin B-12 raised the average serum vitamin B-12 concentration to an amount greater than the lower reference limit. A dose > 350 micrograms/d was required to raise all patients' vitamin B-12 concentrations above this concentration rather than just above the population mean. We conclude that because concentrations of oral crystalline vitamin B-12 were required to normalize serum vitamin B-12 concentrations, that a mechanism other than formation of a vitamin B-12 intrinsic factor complex is responsible for crystalline vitamin B-12 absorption after GB for obesity.

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Calcitonin gene-related peptide (CGRP) is a neuropeptide that is released at the neuromuscular junction in response to nerve excitation. To examine the relationship between plasma CGRP concentration and intracellular glucose metabolism in conscious rats, we performed insulin (22 pmol.kg-1.min-1) clamp studies combined with the infusion of 0, 20, 50, 100, 200, and 500 pmol.kg-1.min-1 CGRP (plasma concentrations ranging from 2 x 10(-11) to 5 x 10(-9) M). CGRP antagonized insulin's suppression of hepatic glucose production at plasma concentrations (approximately 10(-10) M) that are only two- to fivefold its basal portal concentration. Insulin-mediated glucose disposal was decreased by 20-32% when CGRP was infused at 50 pmol.kg-1.min-1 (plasma concentration 3 x 10(-10) M) or more. The impairment in insulin-stimulated glycogen synthesis in skeletal muscle accounted for all of the CGRP-induced decrease in glucose disposal, while whole body glycolysis was increased despite the reduction in total glucose uptake. The muscle glucose 6-phosphate concentration progressively increased during the CGRP infusions. CGRP inhibited insulin-stimulated glycogen synthase in skeletal muscle with a 50% effective dose of 1.9 +/- 0.36 x 10(-10) M. This effect on glycogen synthase was due to a reduction in enzyme affinity for UDP-glucose, with no changes in the maximal velocity. In vitro CGRP stimulated both hepatic and skeletal muscle adenylate cyclase in a dose-dependent manner. These data suggest that 1) CGRP is a potent antagonist of insulin at the level of muscle glycogen synthesis and hepatic glucose production; 2) inhibition of glycogen synthase is its major biochemical action in skeletal muscle; and 3) these effects are present at concentrations of the peptide that may be in the physiological range for portal vein and skeletal muscle. These data underscore the potential role of CGRP in the physiological modulation of intracellular glucose metabolism.

Infections of Cryptobia salmositica Katz, 1951, are common and widely distributed in freshwater teleosts of the Pacific coast from southern British Colmnbia to northern California. The he•noflagellates are reported from 16 species of fish, representing four families and including 10 new hosts. The most susceptible hosts, as indicated by the incidence and intensity of infection, are the pink (Oncorhynchus gorbuscha) and coho (0. kitsutch) salmon, the torrent (Cottus rhotheus) and coastrange sculpin (C. aleuticus), and the longnose dace (Rhinichthys cata-The infected fish are typical cold-water species, occurring only in strea•ns of generally low temperatures, graveled beds, and moderate to swift flowing currents. In this natural environ-

No abstract

The toxicity of several organic insecticides to coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha), rainbow trout (Salmo gairdneri), and the threespine stickleback (Gasterosteus aculeatus) was determined. Toxaphene, aldrin, dieldrin, DDT, lindane, methoxychlor, heptachlor, chlordane, endrin, Guthion, malathion, Co-Ral, and Sevin were tested. Toxicity was determined at 20 ø C. in standing water bioassays which lasted 96 hours. Endrin was the most toxic substance tested; the 96-hour median tolerance limit (TL,•) for coho salmon was 0.51 parts per billion. With the exception of Co-Ral and Sevin, the 96-hour TL,,, values of all insecticides tested were near 100 parts per billion (0.1 p.p.m.), or much less. The toxicity of the insecticides to threespine sticklebacks in waters of 5 and 25 parts per thousand salinity was not markedly different at the two salinities.

Piscicola salmositica Meyer 1946 is widely distributed throughout the Pacific coast of North America from central British Columbia to northern California. Habitual ectoparasites of teleost fishes, these piscicolid leeches are ordinarily encountered in association with spawning adult salmon (genus Oncorhynchus) and other Salmonidae; the common name "salmonid leech" is therefore applied. Piscicola salmositica, in common with its teleost hosts, occurs in a characteristic lotic environment — streams with moderate to swift currents, generally low temperatures, high dissolved oxygen content, and gravelled beds.An annual cycle of abundance is evident. Salmonid leeches appear in early fall attached to their hosts as they ascend into hatchery and natural spawning areas. From late September to February, during a period of feeding, growth, and reproduction, the leech populations attain a great abundance. By late winter, subsequent to the death of their hosts, the leeches have become virtually nonexistent, apparently as a result of high mortality among the mature individuals, some downstream displacement, and limited prédation by sculpins (Cottus sp.). Only the small, immature leeches are believed to survive the summer and return attached to spawning salmon the following fall.During the period of abundance in Soos Creek, a western Washington study stream, the lengths of feeding leeches increased at a rate of 2–3 mm per week. Weight, in relation to length, was dependent upon the amount of salmon blood ingested.Reproduction of salmonid leeches in Soos Creek was correlated with low water temperatures. Breeding began in temperatures of about 12 C in October and continued during December and January even in temperatures dropping to 5 C. The leeches attained sexual maturity at a length of about 15 mm; mature individuals then copulated and fastened cocoons to the lower surfaces of stones in the streambed. Deposited cocoons were dark brown and averaged 1.4 by 1.2 mm. In the laboratory, the average rate of reproduction ranged from 1.6 to 2.5 cocoons per leech per day, but the largest leeches (23–30 mm) produced the greatest number of cocoons. One young leech developed in each cocoon, emerging at a length of about 5.3 mm. Complete embryonic development and hatching occurred in about 7 days.