| morphological and electrophysiological properties of pyramidal-like neurons in the stratum oriens of cornu ammonis 1 and cornu ammonis 2 area of proechimys. | proechimys (rodentia: echimyidae) is a neotropical rodent of the amazon region that has been successfully colonized in the laboratory and used for experimental medicine. preliminary studies indicated that proechimys (casiragua) rodents express an atypical resistance to developing a chronic epileptic condition in common models of temporal lobe epilepsy. moreover, previous investigation of our laboratory described a remarkably different proechimy's cytoarchitecture organization of the hippocampal ... | 2011 | 21215795 |
| ecological studies of enzootic venezuelan equine encephalitis in north-central venezuela, 1997-1998. | from 1997-1998, we investigated the possible continuous circulation of epizootic venezuelan equine encephalitis (vee) virus suggested by a 1983 subtype ic interepizootic mosquito isolate made in panaquire, miranda state, venezuela. the study area was originally covered by lowland tropical rainforest but has been converted into cacao plantations. sentinel hamsters, small mammal trapping, mosquito collections, and human serosurveys were used to detect active or recent virus circulation. six strain ... | 2001 | 11425168 |
| genome composition in venezuelan spiny-rats of the genus proechimys(rodentia, echimyidae). i. genome size, c-heterochromatin and repetitive dnas in situ hybridization patterns. | the genome sizes of the venezuelan spiny-rats proechimys guairae guairae (2n = 48) and p. trinitatis (2n = 62) were evaluated and proved to be 12.5 +/- 0.5 pg and 12.6 +/- 0.3 pg respectively, the highest so far recorded among mammals; also the c-heterochromatin (32.7%, coefficient of variation [cv] 3.8 and 35.8%, cv 4.4) and gc (44.2%, cv 2.7 and 43.6%, cv 2.9) contents are very high. highly repetitive (rep) dnas were isolated from restriction enzyme digested genomic dnas of both species. the i ... | 1997 | 9345903 |
| a monomeric insulin from the casiragua: molecular model building using computer graphics. | interactive computer graphics have been used to construct a three-dimensional model of casiragua insulin assuming a tertiary structural homology with that of porcine insulin. the hydrophobic core of the molecule is conserved, but the hydrophobic surfaces involved in formation of dimers and hexamers in porcine insulin are more hydrophilic and contain charged residues. these observations are consistent with a close similarity of the far ultra violet circular dichroism of casiragua insulin and porc ... | 1981 | 7024088 |
| sharing of biological effect and receptors between guinea pig insulin and platelet-derived growth factor. | insulins from the hystricomorphs (guinea pig, porcupine, coypu, and casiragua) at high concentration stimulate dna synthesis in human fibroblasts to a greater level than other mammalian insulins or insulin-like growth factors (igfs). 125i-labeled guinea pig insulin binds to a specific receptor and this binding is competed for by hystricomorph insulins but not by porcine insulin or igfs. fetal bovine serum also inhibits the binding of 125i-labeled guinea pig insulin and is more potent than fetal ... | 1983 | 6298787 |
| progesterone-binding proteins in plasma of guinea-pigs and other hystricomorph rodents. | progesterone-binding plasma proteins (pbpp, progesterone-binding globulin, pbg, and corticosteroid binding globulin, cbg) have been measured in plasma of guinea-pigs, casiragua, cuis, degu and plains viscacha. during pregnancy pbpp increased to reach peak values between days 20-25 and days 50-term in guinea-pigs, immediately before parturition in casiragua, and in mid-gestation in cuis, degu and viscacha. the pattern of pbpp concentration during pregnancy was similar to that of plasma progestero ... | 1981 | 6170753 |
| coypu insulin. primary structure, conformation and biological properties of a hystricomorph rodent insulin. | insulin from a hystricomorph rodent, coypu (myocaster coypus), was isolated and purified to near homogeneity. like the other insulins that have been characterized in this suborder of rodentia, coypu insulin also exhibits a very low (3%) biological potency, relative to pig insulin, on lipogenesis in isolated rat fat-cells. the receptor-binding affinity is significantly higher (5-8%) in rat fat-cells, in rat liver plasma membranes and in pig liver cells, indicating that the efficacy of coypu insul ... | 1986 | 3541911 |
| molecular evolution of rodent insulins. | several trees of amino acid sequences of rodent insulins were derived with the maximum-parsimony procedure. possible orthologous and paralogous relationships were investigated. except for a recent gene duplication in the ancestor of rat and mouse, there are no strong arguments for other paralogous relationships. therefore, a tree in agreement with other biological data is the most reasonable one. according to this tree, the capacity to form zinc-binding hexamers was lost once in the ancestor of ... | 1987 | 3328814 |
| the n-terminal hexapeptide fragment of igf ii stimulates thymidine incorporation into fibroblasts. | we synthesized the n-terminal hexapeptide fragment of igf ii to study potential binding to nmda receptors in analogy to the n-terminal tripeptide of igf i. the amino acid sequence of the hexapeptide is furthermore identical with the c-terminal sequence of the casiragua insulin b chain. the hexapeptide did not bind to the nmda receptors, but was found to promote [3h]-thymidine incorporation into fibroblasts at concentrations of 10(-8) - 10(-5) m in a dose-dependent manner. since [125i]-hexapeptid ... | 1992 | 1355652 |
| the myoglobin of rodents proechimys guairae (casiragua) and mus musculus (house mouse). | the amino acid sequences of the myoglobins of two rodents, the casiragua and the house mouse, have been determined. the myoglobin of casiragua differs from that of viscacha (another hystricomorph) at 6 positions. mouse myoglobin differs from that of mole-rat (another myomorph) at 17 positions, whereas casiragua and mouse differ at 22 positions. mouse myoglobin possesses several features unique among all known myoglobins (gly 31, cys 66, thr 74 and glu 113) and one substitution unique among known ... | 1985 | 4043406 |
| the spiny rat proechimys guyannensis as model of resistance to epilepsy: chemical characterization of hippocampal cell populations and pilocarpine-induced changes. | at variance with pilocarpine-induced epilepsy in the laboratory rat, pilocarpine administration to the tropical rodent proechimys guyannensis (casiragua) elicited an acute seizure that did not develop in long-lasting status epilepticus and was not followed by spontaneous seizures up to 30 days, when the hippocampus was investigated in treated and control animals. nissl staining revealed in proechimys a highly developed hippocampus, with thick hippocampal commissures and continuity of the rostral ... | 2001 | 11457585 |
| the primary structures of pancreatic ribonucleases from african porcupine and casiragua, two hystricomorph rodent species. | the amino acid sequences of the pancreatic ribonucleases from african porcupine (hystrix cristata) and casiragua (proechimys guairae, a caviomorph rodent species related to the coypu) were determined. the ribonucleases were isolated form minces of pancreatic tissue which had been used for the extraction of the insulins. the results of the sequence determinations of residues 67-78 in both enzymes were ambiguous. therefore, homology with other ribonucleases has been used in deriving these sequence ... | 1982 | 7115727 |
| high incidence of dystokia in the casiragua (proechimys guairae). | dystokia caused the deaths of 8 casiraguas out of a total of 25 adult females examined post mortem from a small colony of this rodent on exhibition at the london zoo. | 1980 | 7464015 |
| another hystricomorph rodent: keeping casiragua (proechimys guairae) in captivity. | | 1973 | 4712301 |
| proceedings: acrosomal changes in spermatozoa of the casiragua, proechimys guairae (rodentia: hystricomorpha), during passage through the epididymis: maturation or senescence? | | 1974 | 4819336 |