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151.
Summary Adult rainbow trout (Oncorhynchus mykiss) were injected intraperitoneally with capsaicin, substance P, serotonin, or a control of saline vehicle or bovine serum albumin (0.5 g/g body weight). Fish were sacrificed 30 min and 1,2 and 4 h post-injection, the gut was dissected out, and a small section of the upper intestine was processed for electron microscopy. A significant proportion of eosinophilic granule cells (EGCs) of the intestine were in close association with non-myelinated neuronal bundles in all fish (4 fish per treatment and time period), but there was no significant difference between treatment or time, suggesting that the association was unaffected by these factors. Close examination of EGC ultrastructure showed that fish treated with capsaicin and substance P exhibited limited degranulation of the EGCs in the stratum compactum and extensive crinophagic-like degranulation in the lamina propria. Cells of the lamina propria contained characteristic multivesicular-like bodies. The degranulation was reminiscent of both mast cell degranulation and endocrine cell crinophagy. EGCs of fish treated with serotonin or a control were unaffected, suggesting that the serotoninergic neurons, believed to be involved in gut motility, were not responsible for degranulation. It is apparent that EGCs of the trout intestine may be under nervous control, as has been demonstrated previously for mammalian mast cells. 相似文献
152.
Kenneth T. Izutsu Mark K. Goddard Jeanne M. Iversen Murray R. Robinovitch Teresa K. Oswald Marie Cantino Dale Johnson 《Cell and tissue research》1991,263(3):535-540
Summary The relationship between granule density, protein content, and Ca and S contents were studied in two secretory granule fractions, from parotid glands of the rat, previously shown to constitute different stages in granule maturation. The density of the lighter fraction was between 1.133 and 1.142 g/ml, while that of the heavier fraction was greater than 1.142 g/ml. The mean protein content of the denser granules was 12% greater than that of the lighter granules (P<0.03), while the dry-mass elemental concentrations in the two granule fractions were unchanged. These results indicate that protein is added to granules during the maturation process (presumably by vesicular traffic), and that the resulting increase in granule density is not driven simply by decrease in water content and/or increased concentrations of inorganic Ca or S in the granules. The elemental concentration values also indicate that the diffusible elements permeate the granule membrane during the fractionation procedures. 相似文献
153.
Mark A. Dersch William M. Bement Carolyn A. Larabell Michael D. Mecca David G. Capco 《Cell and tissue research》1991,263(2):375-383
Summary The giant mucous cells in the skin of the terrestrial banana slug Ariolimax columbianus secret intact granules containing mucins. Electron microscopy, after ultrarapid freezing and freeze-substitution in osmium, shows that the secreted granules are bounded by two distinct membranes, presumably derived from the Golgi apparatus and the plasmalemma. Relatively stable, intact granules can be obtained in great quantity in our in vitro system. Rapid lysis of the granules was induced by adenosine triphosphate. At much higher concentrations, adenosine diphosphate and 5-adenylimido-diphosphate also caused lysis. Other nucleotides and related compounds, as well as 1,4,5-inositol triphosphate and molluscan neurotransmitters and neuropeptides, had no effect on the granules. The stability of secreted granules varied with the ionic composition of the isosmotic medium in which they were suspended. When the predominant cation in the medium was potassium, and calcium was also present, granules lysed if exposed to shear stress (stirring of the suspension). This did not occur if sodium was the major cation present. None of the other ions in the suspension media had detectable effects on the stability of the granules. 相似文献
154.
Stephen G. Swisher Timothy M. Anderson Duan-Ren Wen Mark A. Stene Alistair J. Cochran Sidney H. Golub E. Carmack Holmes 《Cancer immunology, immunotherapy : CII》1991,33(5):327-332
Summary We administered preoperative low-dose interleukin-2 (IL-2) to 10 patients undergoing thoracotomy for pulmonary tumors. The in vivo effect of IL-2 on tumor-associated lymphocyte activity was assessed in the resected specimens by immunohistochemistry and compared with observations in 45 patients who did not receive IL-2. H & E evaluation revealed an increase in intra- and peritumoral lymphocyte infiltration in the IL-2-treated patients. Immunopathological evaluation with monoclonal antibodies revealed that this lymphocyte infiltration was predominantly CD5-positive T cells. The amount of intra-and peritumoral lymphocyte activity correlated with the dose of IL-2 administered (6000–90 000 international units/kg every 8 h for 48 h. IL-2-treated patients showed increases in T-cell-associated activation markers (IL-2 -receptor, transferrin receptor and HLA-DR) on peritumoral lymphocytes, but not on intratumoral lymphocytes. We previously reported that low-dose IL-2 increases the intrinsic natural killer cell cytotoxicity of intratumoral lymphocytes and suggest that this lymphocyte infiltration is further evidence that low-dose IL-2 can augment in vivo lymphocyte activity at the tumor site.This work was supported in part by USPHS grants CA 44 352 (S. H. G.) and 43 658 (A. J. C.). S. G. S. was supported by NIH Surgical Oncology Training Grant CA 09 010 相似文献
155.
Odor-modulated upwind flight of the sphinx moth,Manduca sexta L. 总被引:1,自引:0,他引:1
Mark A. Willis Edmund A. Arbas 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(4):427-440
1. Male and female Manduca sexta flew upwind in response to the odor of female sex-pheromone gland extract or fresh tobacco leaf respectively, and generated very similar zigzagging tracks along the odor plume. 2. After loss of odor during flight, males and females alike: (1) first flew slower and steered their flight more across the wind, then (2) stopped moving upwind, and finally (3) regressed downwind. 3. Males flying upwind in a pheromone plume in wind of different velocities maintained their ground speed near a relatively constant 'preferred' value by increasing their air speed as the velocity of the wind increased, and also maintained the average angle of their resultant flight tracks with respect to the wind at a preferred value by steering a course more precisely due upwind. 4. The inter-turn duration and turn rate, two measures of the temporal aspects of the flight track, were maintained, on average, with remarkable consistency across all wind velocities and in both sexes. The inter-turn durations also decreased significantly as moths approached the odor source, suggesting modulation of the temporal pattern of turning by some feature of the odor plume. This temporal regularity of turning appears to be one of the most stereotyped features of odor-modulated flight in M. sexta. 相似文献
156.
Karen F. Greif Mark G. Erlander Niranjala J. K. Tillakaratne Allan J. Tobin 《Neurochemical research》1991,16(3):235-242
The recent identification of two genes encoding distinct forms of the GABA synthetic enzyme, glutamate decarboxylase (GAD), raises the possibility that varying expression of the two genes may contribute to the regulation of GABA production in individual neurons. We investigated the postnatal development the two forms of GAD in the rat cerebellum. The mRNA for GAD67, the form which is less dependent on the presence of the cofactor, pyridoxal phosphate (PLP), is present at birth in presumptive Purkinje cells and increases during postnatal development. GAD67 mRNA predominates in the cerebellum. The mRNA for GAD65, which displays marked PLP-dependence for enzyme activity, cannot be detected in cerebellar cortex by in situ hybridization until P7 in Purkinje cells, and later in other GABA neurons. In deep cerebellar nuclei, which mature prenatally, both forms of GAD mRNA can be detected at birth. The amounts of immunoreactice GAD and GAD enzyme activity parallel changes in mRNA levels. We suggest that the delayed appearance of GAD65 is coincident with synapse formation between GABA neurons and their targets during the second postnatal week. GAD67 mRNA may be present prior to synaptogenesis to produce GABA for trophic and metabolic functions.Special issue dedicated to Dr. Eugene Roberts. 相似文献
157.
The role played by cell addition, cell enlargement, and matrix deposition in the endochondral growth of the condyle was assessed in weanling rats by four approaches making use of the light microscope: morphometry, 3H-thymidine radioautography, 3H-proline radioautography, and immunostaining for the cartilage-specific type II collagen. From the articular surface down, the condyle may be divided into five layers made up of cells embedded in a matrix: 1) the articular layer composed of static cells in a matrix rich in fibers presumed to be of type I collagen, 2) the polymorphic cell layer including the progenitor cells from which arise the cells undergoing endochondral changes, 3) the flattened cell layer in which cells produce a precartilagenous matrix devoid of type II collagen while undergoing differentiation in two stages: a "chondroblast" stage and a short "flattened chondrocyte" stage when intracellular type II collagen elaboration begins, 4) the upper hypertrophic cell layer, in which cells are "typical chondrocytes" that enlarge at a rapid rate, actively produce type II collagen, and deposit it into a cartilagenous matrix, and 5) the lower hypertrophic cell layer, composed of chondrocytes at a stage of terminal enlargement while the cartilagenous matrix is adapting for mineralization. 3H-thymidine radioautographic results indicate that the turnover time of progenitor cells in the polymorphic cell layer is about 2.9 days. The time spent by cells at each stage of development is estimated to be 1.4 days as chondroblasts, 0.5 days as flattened chondrocytes, 2.3 days as the chondrocytes of the upper hypertrophic cell layer, and 1.1 days as those of the lower hypertrophic cell layer. Calculations referring to a 1 x 1-mm square-sided column extending from the articular surface to the zone of vascular invasion provide the daily rate of cell addition (0.0077 mm3), extracellular matrix deposition (0.0127 mm3), and cell enlargement (0.0302 mm3). Hence the respective contribution of the three factors to condyle growth is in a ratio of about 1:1.6:4. This result emphasizes the role played by cell enlargement in the overall growth of the condyle. 相似文献
158.
Junhyong Kim Mark A. Burgman 《Evolution; international journal of organic evolution》1988,42(3):596-602
A comparative study of the accuracy of three different approaches to phylogenetic estimation was made on simulated data with differing rates of change in different lineages. The three approaches were maximum likelihood, maximum parsimony, and phenetic clustering. The data were generated by simulating genetic drift with different population sizes over a simple four-species tree topology. Although the accuracy of all three approaches was found to be dependent on the number of loci (characters), maximum likelihood was found to perform considerably and consistently better than maximum parsimony or phenetic clustering. 相似文献
159.
Experimental effects of elevated salinity on three benthic invertebrates in Pyramid Lake,Nevada 总被引:7,自引:7,他引:0
Salinity of Pyramid Lake increased from 3.7 to 5.5 between 1933 and 1980. Concern over future reductions in overall species richness prompted experiments to assess responses of dominant lake organisms to elevated salinity. Salinity tolerances of three important benthic invertebrates, Hyalella aztecta, Chironomus utahensis, and Heterocypris sp., were tested in controlled laboratory bioassays and also in a semi-natural environment consisting of large (47 m3) mesocosms.Densities of H. azteca in mesocosms were significantly lower at salinities of 8.0 and 11.0 compared with 5.6 controls in year one, but not in 8.5 salinity mesocosms in year two. The 96-h LC50 for H. azteca was high at 19.5. Short-term mortalities of C. utahensis were 100% at salinities of 13.3 and greater. Fifty-seven percent fewer larvae matured from third to fourth instar at 8.9 than at 5.5 salinity in 17 day subacute bioassays. Furthermore, larval chironomid densities and emergence of adults from mesocosms were significantly reduced at salinities of 8.0 and higher compared with controls. Mortality of Heterocypris sp. was 50% at a salinity of 18.6 in laboratory bioassays and populations in mesocosms ranged between 40 and 100% lower at salinities of 8.0 and 11.0 than in controls.Multiple generation mesocosm experiments indicated all three invertebrates were more sensitive to elevated salinity than results of short-term bioassays. Our studies suggest populations of these invertebrates may be reduced from present levels if Pyramid Lake's salinity were to double, although none are expected to be extirpated. Food habit shifts and reduced production of lake fishes are likely consequences of salinity-induced disruption in the benthic invertebrate forage base. 相似文献
160.
Consumption of leaf detritus by a stream shredder: Influence of tree species and nutrient status 总被引:8,自引:3,他引:5
Four species of riparian vegetation (alder, birch, willow and poplar) were fertilized with nitrogen, phosphorus, nitrogen
+ phosphorus, or no fertilizer (control). The resulting leaf detritus (leached but not microbially colonized) was offered
to a stream shredder, Hydatophylax variabilis (Trichoptera: Limnephilidae). In one experiment, shredder consumption of leaf detritus from different nutrient treatments
(within tree species) was compared, and in a second experiment, consumption of different tree species (within nutrient treatments)
was compared. Larvae preferred leaf detritus from nitrogen + phosphorus treatments (except in poplar where nitrogen treatment
was preferred). Alder was preferred over other tree species for all treatments. Chemical and physical analyses of leaf litter
showed differences between tree species and nutrient treatments in nutrient content, tannins and leaf toughness. Leaf consumption
by larvae was positively associated with nitrogen content and negatively associated with condensed tannin content. Species
composition and nutrient status of riparian vegetation may strongly influence detrital food webs in streams. 相似文献