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81.
Glycosaminoglycan biosynthesis in the isolated perfused rat lung 总被引:1,自引:0,他引:1
Sampson P. M.; Boyd R. B.; Pietra G. G.; Fishman A. P. 《Journal of applied physiology》1984,57(6):1648-1654
82.
Skeletal changes associated with vascular malformations 总被引:5,自引:0,他引:5
J B Boyd J B Mulliken L B Kaban J Upton J E Murray 《Plastic and reconstructive surgery》1984,74(6):789-797
Five hundred and eighty birthmarks were reviewed; 356 were hemangiomas and 224 were malformations. Bony alterations occurred in association with only 1 percent of hemangiomas, in contrast with 34 percent of patients with vascular malformations. These alterations in bone development were classified according to size, shape, and density changes. Hypertrophy and distortion were typical of lymphatic malformations. Hypoplasia and demineralization were characteristic findings in the extremity venous malformations. Destructive and intraosseous changes were more commonly noted in the arterial or high-flow lesions. Possible mechanisms of altered skeletal growth include mechanical, physiological, and developmental processes. 相似文献
83.
Synopsis The spawning periodicity and mating behavior of a northern population of the Atlantic silverside, Menidia menidia, was studied both in the field (Salem Harbor, Massachusetts) and in laboratory experiments. Spawning in the field coincided
with new and full moons. Under conditions of unlimited food availability in artificial outdoor pools that received natural
celestial illumination or in indoor aquaria receiving no evening illumination, spawning occurred every 1–3 days rather than
fortnightly. These results suggest that tidal influences are a primary factor that synchronizes spawning in M. menidia. Published reports of diel time of spawning in both marine and freshwater species of Menidia indicate a generic tendency to spawn during mid-morning. This pattern coupled with high tides that cover suitable spawning
substrates during mid-morning only at fortnightly intervals could account for the semilunar spawning cycle in marine populations
of Menidia. Although general characteristics of the reproductive ecology of M. menidia in Massachusetts were similar to a thoroughly studied population in South Carolina, several differences were evident. The
breeding season was shorter in Massachusetts (late; April–June), and occurred over a much lower range of temperatures (9–21°C).
Intensity and frequency of spawning was correlated with the height of high tide. Eggs were deposited only on mats of intertidal,
filamentous algae rather than on roots or stems of Spartina alterniflora or other intertidal vegetation. Promiscuous spawning occurred in small, highly male-dominated groups of fish, primarily after
the tide had begun to recede, and often at the water's edge. No predation on spawning adults was observed but the mummichog,
Fundulus heteroclitus, fed daily on developing embryos during high tide.
Contribution No. 81, Massachusetts Cooperative Fisheries Research Unit, Contribution No. 349, Marine Sciences Research Center,
State University of New York at Stony Brook. 相似文献
84.
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86.
Gentamicin is a very useful antimicrobial agent for the treatment of serious infections caused by gram-negative bacteria. However, it's low therapeutic index and potential ototoxic and nephrotoxic side effects necessitate frequent determinations of serum concentration to assist in maintaining therapeutic levels and avoiding toxic levels. Two bioassays and a latex agglutination inhibition card (LAIC) test were evaluated to determine gentamicin levels in nearly 100 patient sera. Results were compared with a radioimmunoassay (RIA). Two bioassays, the Bio-Monitor and the GentaSak, gave correlation coefficients of 0.987 and 0.982, respectively. The correlation coefficient for the LAIC test was 0.987. All three tests compared well with RIA in accurately detecting gentamicin levels in patient as well as simulated sera. The LAIC test, however, was more rapid, giving results within half an hour whereas bioassays required 6–8 hours for completion. The LAIC test was also found to be more economical. It provides a suitable alternative to RIA procedures in small laboratories and for performing stat tests since batching is not necessary. 相似文献
87.
J F Keana S A Boyd D A McMillen E M Bernard P C Jost 《Chemistry and physics of lipids》1982,31(4):339-349
The synthesis of a series of amphipathic nitroxide lipid spin labels is reported. Thus, 12-proxylhexadecanol has been converted into the versatile fatty acid spin label 14-proxylstearic acid. This substance was used to prepare 14-proxylstearyltrimethylammonium methanesulfonate, a positively charged label, and 14-proxylstearylmethyl phosphate sodium salt, a negatively charged label. Also prepared in the doxyl series were quaternary ammonium salts derived from 16-doxyl- and 7-doxylstearic acid. The positively charged and negatively charged proxyl labels were used in a preliminary experiment to investigate the role of charge in their interaction with reconstituted cytochrome oxidase. The average binding affinity of the negatively charged label is approximately 2-fold higher than that of the positively charged label at pH 7.4. At pH 5.5 the average relative affinity for negatively charged label is about 3.5-fold higher than that of positively charged label, suggesting that the ionizable group(s) on the protein can interact with the lipid headgroup. 相似文献
88.
Thyrotropin-releasing hormone facilitates display of reproductive behavior and locomotor behavior in an amphibian 总被引:1,自引:0,他引:1
In the amphibian brain, thyrotropin-releasing hormone (TRH) is present in many regions outside the hypothalamus. The functions of this extrahypothalamic TRH however are unknown. We sought to determine whether TRH or its metabolites altered reproductive behaviors (amplectic clasping behavior) or locomotor behaviors of the male South African clawed frog, Xenopus laevis. TRH-injected (100 micrograms; dorsal lymph sac injection) male Xenopus displayed significantly fewer amplectic clasp attempts and longer clasp durations than saline-injected controls. The TRH metabolites, TRH acid and histidylproline diketopiperazine, similarly altered clasping behavior. Several hormones released by TRH, including thyroid-stimulating hormone, melanocyte-stimulating hormone, prolactin, and dopamine, had no significant effect on clasp frequency or duration. Locomotor activity in Xenopus males was increased significantly after 15 min following TRH injection (150 micrograms); this effect persisted for at least 1 hr. The metabolites did not alter locomotion. These studies indicate that TRH can facilitate the display of two behaviors in the South African clawed frog. Effects of TRH on locomotor and reproductive behaviors thus appear in several vertebrate classes. These behavioral actions of TRH likely occur through different mechanisms or at different sites. 相似文献
89.
S K Boyd 《Hormones and behavior》1991,25(1):57-69
Although neurohypophysial peptides are present in many regions of the developing and adult bullfrog (Rana catesbeiana) brain, the function of these peptides remains unclear. To investigate possible behavioral actions, we examined locomotor activity following peptide injection in bullfrogs at various developmental stages. An intraperitoneal (ip) injection of arginine vasotocin (AVT) in tadpoles (stages V, X, or XVII) produced an immediate and dose-dependent inhibition of locomotor activity. On the other hand, AVT stimulated activity when administered ip to juvenile or adult female bullfrogs, but did not influence activity in juvenile or adult males. The minimum effective dose of AVT, when injected directly into the brain of tadpoles, was 100-fold less than that observed when injected ip, suggesting a central nervous system site of action for this peptide. A vasopressin receptor antagonist (d(CH2)5[Tyr(Me)2]AVP administered ip or icv) significantly increased locomotor activity in tadpoles, compared to controls. Oxytocin, vasopressin, and AVP4-9 inhibited activity in tadpoles while mesotocin, des Gly(NH2)AVP, and pressinoic acid had no significant effect. Injection of PGF2 alpha also significantly decreased activity levels in tadpoles. However, pretreatment of tadpoles with indomethacin, a prostaglandin synthesis inhibitor, did not prevent the behavioral effects of AVT, suggesting that prostaglandin synthesis is not required for this response. In summary, AVT influenced locomotor activity in bullfrog tadpoles and female frogs. This effect shifted during development from an inhibitory action in tadpoles to a stimulatory effect in metamorphosed female frogs. The effect of AVT on juvenile and adult frog locomotion was sexually dimorphic, as this peptide altered female behavior but not male behavior. 相似文献
90.