| the antihemorrhagic factor of the mexican ground squirrel, (spermophilus mexicanus). | the mexican ground squirrel (spermophilus mexicanus) has a natural resistance to western diamondback rattlesnake venom (crotalus atrox). the ld50 for the mexican ground squirrel is 53 mg/kg body weight, which is 13 times higher than that of balb/c mice. an antihemorrhagic factor from serum of the mexican ground squirrel was isolated using sephadex g-200 gel filtration, ion exchange a-50, g-75 gel filtration and hplc deae 5pw ion exchange chromatography. the purified factor neutralized proteolyti ... | 1999 | 10340834 |
| neutralization of venoms from two southern pacific rattlesnakes (crotalus helleri) with commercial antivenoms and endothermic animal sera. | the southern pacific rattlesnake (crotalus helleri) is found in southwestern california (usa), southward through north baja california (mx) into the northern part of southern baja california (mx). in this study, the venoms from two southern pacific rattlesnakes were characterized. the two venoms were different in color, concentration, and enzyme activities. two commercial antivenoms neutralized both c. helleri venoms differently. antivipmyn (fab2h) and crofab (fabo) neutralized both venoms but h ... | 2004 | 15284013 |
| screening for fibrinolytic activity in eight viperid venoms. | snake venoms contain direct-acting fibrinolytic metalloproteinases (mmp) that could have important applications in medicine. fibrinolytic enzymes isolated from venom can induce in vitro clot lysis by directly acting on a fibrin clot. the most ideal fibrinolytic enzyme would have high affinity for clots, dissolve clots directly without causing hemorrhage, and would not be neutralized in vivo by endogenous metalloproteinase inhibitors. the purpose of this study was to compare deae/hplc venom profi ... | 1999 | 10579653 |
| a laboratory study of social behaviour of pairs of females during the reproductive season in spermophilus spilosoma and spermophilus mexicanus. | spermophilus spilosoma and spermophilus mexicanus are closely related species with a low degree of sociality. they are sympatric in the bolson de mapimi (chihuahua desert, mexico), where they occupy similar ecological niches. in sciurid rodents, advanced social structures may have evolved through the formation of sedentary female groups. the purpose of this study is to compare the ability of s. spilosoma and s. mexicanus females to cohabit with another conspecific female under space constraints ... | 1996 | 24897437 |
| retinal neurons of the california ground squirrel, spermophilus beecheyi: a golgi study. | although the optic nerve fibers of the cone-dominant ground squirrel retina have been well studied physiologically, the morphological details of the retinal neurons have not. to that end, retinal neurons of the california ground squirrel have been studied in golgi-impregnated wholemounts. two types of horizontal cell have been identified: h1 has an axon and axon terminal, whereas h2 is axonless. the dendritic field of h1 cells enlarges in a nonuniform manner with increasing displacement from the ... | 1996 | 8822165 |
| non-suppressibility by room light of pineal n-acetyltransferase activity and melatonin levels in two diurnally active rodents, the mexican ground squirrel (spermophilus mexicanus) and the eastern chipmunk (tamias striatus). | the rhythms in pineal n-acetyltransferase (nat) activity and melatonin levels were studied in the diurnally active mexican ground squirrel and eastern chipmunk. in the ground squirrel, both nat activity and melatonin levels exhibited a marked nocturnal rise; these increases were not prevented by the exposure of these animals to a light irradiance of 200 microw/cm2 throughout the night. in the eastern chipmunk, darkness at night was also associated with a marked rise in both the activity of the a ... | 1984 | 6541997 |
| hybridization in the mexican and 13-lined ground squirrels, spermophilus mexicanus and spermophilus tridecemlineatus. | evidence of hybridization between the ground squirrels, spermophilus tridecemlineatus and s. mexicanus is presented on the basis of chromosomal and protein data. the hybrids produced appear to be completely interfertile. based on the evidence of hybridization and the recent reestablishment of contact between these two species, they are considered to be semispecies. | 1976 | 950012 |
| the response of erythrocyte organic phosphate levels of active and hibernating ground squirrels (spermophilus mexicanus) to isobaric hyperoxia. | | 1973 | 4145704 |
| responses of some hematologic parameters of active and hibernating squirrels (spermophilus mexicanus) upon exposure to hypobaric and isobaric hyperoxia. | | 1972 | 4405344 |
| torpidity in the mexican ground squirrel citellus mexicanus parvidens (mearns). | | 1965 | 14287034 |