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311.
Jianhua Zhang Mei Liu Hongjian Jin Liandong Deng Jinfeng Xing Anjie Dong 《AAPS PharmSciTech》2010,11(2):894-903
Lactate esters are widely used as food additives, perfume materials, medicine additives, and personal care products. The objective
of this work was to investigate the effect of a series of lactate esters as penetration enhancers on the in vitro skin permeation of four drugs with different physicochemical properties, including ibuprofen, salicylic acid, dexamethasone
and 5-fluorouracil. The saturated donor solutions of the evaluated drugs in propylene glycol were used in order to keep a
constant driving force with maximum thermodynamic activity. The permeability coefficient (K
p), skin concentration of drugs (SC), and lag time (T), as well as the enhancement ratios for K
p and SC were recorded. All results indicated that lactate esters can exert a significant influence on the transdermal delivery
of the model drugs and there is a structure-activity relationship between the tested lactate esters and their enhancement
effects. The results also suggested that the lactate esters with the chain length of fatty alcohol moieties of 10–12 are more
effective enhancers. Furthermore, the enhancement effect of lactate esters increases with a decrease of the drug lipophilicity,
which suggests that they may be more efficient at enhancing the penetration of hydrophilic drugs than lipophilic drugs. The
influence of the concentration of lactate esters was evaluated and the optimal concentration is in the range of 5∼10 wt.%.
In sum, lactate esters as a penetration enhancer for some drugs are of interest for transdermal administration when the safety
of penetration enhancers is a prime consideration. 相似文献
312.
313.
P N Tonin R L Stallings M D Carman J R Bertino J A Wright P R Srinivasan W H Lewis 《Cytogenetics and cell genetics》1987,45(2):102-108
We have shown previously that cDNAs for the M1 and M2 subunits of ribonucleotide reductase, ornithine decarboxylase (ODC), and p5-8, a 55,000-Dalton protein, hybridize to amplified genomic sequences in a highly hydroxyurea-resistant hamster cell line. We have extended these observations to include two additional, independently isolated, hydroxyurea-resistant cell lines: SC8, a single-step hamster ovary cell line, and KH450, a multistep human myeloid leukemic cell line, have also undergone genomic amplification for sequences homologous to ODC and p5-8 cDNAs. However, neither SC8 nor KH450 contains amplified genomic sequences homologous to an M1 cDNA probe. A panel of mouse-hamster somatic cell hybrids was used to map sequences homologous to M1, M2, ODC, and 5-8 cDNAs in the hamster genome. The M2, ODC, and p5-8 cDNAs hybridized to DNA fragments that segregated with hamster chromosome 7. In contrast, M1 cDNA hybridized to DNA fragments that segregated with hamster chromosome 3. These data suggest that the genes RRM2, (M2), ODC, and p5-8, but not RRMI (M1), are linked and may have been co-amplified in the selection of the hydroxyurea-resistant hamster and human cell lines. 相似文献
314.
N V Dariski? A I Turilova R Korbut E Marchenkevich 《Biulleten' eksperimental'no? biologii i meditsiny》1982,93(5):74-76
It was shown in in vitro experiments that etmozin at a concentration of 100 micrograms/ml significantly suppressed (by 21%) platelet aggregation induced by ADP, but it had no effect on platelet aggregation induced by arachidonic acid. In in vivo experiments etmozin was found to cause a marked suppression of tendon collagen-induced platelet aggregation in the doses 2-5 mg/kg having antiarrhythmic activity. Under suppressed platelet aggregation induced by indomethacin, the prostaglandin biosynthesis blocker etmozin displayed no antiaggregation effect. It is suggested that etmozin effects on ADP release from platelets play the main role in the mechanism of its antiaggregation action. 相似文献
315.
Hugues Bersini 《Origins of life and evolution of the biosphere》2010,40(2):121-130
There is a long tradition of software simulations in theoretical biology to complement pure analytical mathematics which are
often limited to reproduce and understand the self-organization phenomena resulting from the non-linear and spatially grounded
interactions of the huge number of diverse biological objects. Since John Von Neumann and Alan Turing pioneering works on
self-replication and morphogenesis, proponents of artificial life have chosen to resolutely neglecting a lot of materialistic
and quantitative information deemed not indispensable and have focused on the rule-based mechanisms making life possible,
supposedly neutral with respect to their underlying material embodiment. Minimal life begins at the intersection of a series
of processes which need to be isolated, differentiated and duplicated as such in computers. Only software developments and
running make possible to understand the way these processes are intimately interconnected in order for life to appear at the
crossroad. In this paper, I will attempt to set out the history of life as the disciples of artificial life understand it,
by placing these different lessons on a temporal and causal axis, showing which one is indispensable to the appearance of
the next and how does it connect to the next. I will discuss the task of artificial life as setting up experimental software
platforms where these different lessons, whether taken in isolation or together, are tested, simulated, and, more systematically,
analyzed. I will sketch some of these existing software platforms: chemical reaction networks, Varela’s autopoietic cellular
automata, Ganti’s chemoton model, whose running delivers interesting take home messages to open-minded biologists. 相似文献
316.
I. N. Pigarev 《Neurophysiology》1984,16(6):580-584
The character of eye movements during electrical stimulation of the medial wall of the brain beneath the cruciate sulcus and of the inferior wall of the cruciate sulcus itself in the frontal cortex was investigated in waking cats. Stimulation of this part of the brain evoked two types of eye movements: unidirectional concomitant saccades, whose direction and amplitude were independent of the original position of the eyes in the orbits, and saccades into the central position (so-called centering saccades). Unidirectional saccades appeared in response to stimulation of the caudal part of the investigated zone, centering saccades in response to stimulation of its rostral part. Analysis of the directions and amplitudes of unidirectional saccades suggested the retinotopic organization of the caudal zone. Systematic changes in the magnitude and direction of vertical saccades during stimulation of the deep parts of the cruciate sulcus indicated previsely the projection of the vertical meridian of the retina. Reappearance of vertical saccades evoked by stimulation of certain parts of the medial wall of the brain suggests the existence of more than one retinotopically organized zone in this region. Inconstancy of stereotaxic coordinates of the oculomotor area, studied in different animals, was noted.Institute for Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 16, No. 6, pp. 761–766, November–December, 1984. 相似文献
317.
Distinct transcriptional profiles of adipogenesis in vivo and in vitro. 总被引:14,自引:0,他引:14
A Soukas N D Socci B D Saatkamp S Novelli J M Friedman 《The Journal of biological chemistry》2001,276(36):34167-34174
318.
N A Shanina V I Gel'fand I I Dykhanov N G Bronza N N Rozinova 《Biulleten' eksperimental'no? biologii i meditsiny》1986,101(1):84-86
The method of extraction of ciliated epithelium from biopsy samples of human bronchial mucosa with glycerol is suggested. Permeabilized cilia of glycerol-extracted cells can be easily reactivated by exogenous ATP. This method was used for the study of ciliary dyskinesia in patients with chronic lung diseases. It was shown that in patients with Kartagener's syndrome neither freshly-isolated, nor glycerol-extracted ATP-treated cilia were motile. On the other hand, in some patients with bronchial asthma ATP reactivated glycerol-extracted cilia, while cilia of freshly-isolated cells remained immotile. The study shows that glycerol permeabilization and reactivation by ATP can be used for the analysis of cilial contractile apparatus in patients with chronic lung disease. 相似文献
319.
Biogeographical analyses are applied to skipper (Hesperioidea) presence/absence data from the Western Mediterranean mainland
and the three largest islands (Sardinia, Corsica and Sicily) in order to identify potential conservation issues. The analyses
performed on species, both collectively and individually, indicate that regional species richness and occurrence in the Mediterranean
zone are largely predicted by latitude and area but that islands have impoverished faunas. Several species, predicted to be
present on these islands from logistic regression of their continental distributions, are actually absent. The number of species
predicted to be present from logistic regression analyses for each island, closely matched the number of species predicted
to occur in regional-focused multiple regression analysis. This suggests that missing species have been identified. When compared
with species that occur in Sicily and Corsica, the missing species are shown to differ for ecological traits, mainly those
linked to altitudinal tolerance. No ecological distinctions were disclosed for Sardinian skippers suggesting a mainly stochastic
colonisation. These results, and those from an analogous study carried out on Papilionoidea, point to Hesperioidea having
(i) overall more impoverished faunas on islands and (ii) being subject to stochastic or historical colonisation events more
than Papilionoidea. Species not predicted to occur on islands based on their mainland distributions and ecological traits,
are foci for conservation attention. However, as many species becoming extinct on the islands may be irreplaceable, all species,
in particular the Sardinian ones, deserve to be conserved. 相似文献
320.