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561.
CM Fuller II Ismailov BK Berdiev VG Shlyonsky DJ Benos 《Canadian Metallurgical Quarterly》1996,271(43):26602-26608
We have recently cloned the alpha subunit of a bovine amiloride-sensitive Na+ channel (alphabENaC). This subunit shares extensive homology with both rat and human alphaENaC subunits but shows marked divergence at the C terminus beginning at amino acid 584 of the 697-residue sequence. When incorporated into planar lipid bilayers, alphabENaC almost exclusively exhibits a main transition to 39 picosiemens (pS) with very rare 13 pS step transitions to one of two subconductance states (26 and 13 pS). In contrast, the alpha subunit of the rat renal homolog of ENaC (alpharENaC) has a main transition step to 13 pS that is almost constituitively open, with a second stepwise transition of 26 to 39 pS. A deletion mutant of alphabENaC, encompassing the entire C-terminal region (R567X), converts the kinetic behavior of alphabENaC to that of alpharENaC, i. e. a transition to 13 pS followed by a second 26 pS transition to 39 pS. Chemical cross-linking of R567X restores the wild-type alphabENaC gating pattern, whereas treatment with the reducing agent dithiothreitol produced only 13 pS transitions. In contrast, an equivalent C-terminal truncation of alpharENaC (R613X) had no effect on the gating pattern of alpharENaC. These results are consistent with the hypothesis that interactions between the C termini of alphabENaC account for the different kinetic behavior of this member of the ENaC family of Na+ channels. 相似文献
562.
AK Barsukov VA Obukhov OIu Nesterova SA Ushnurtseva KA Lapin OV Kozhevnikova AI Kuznetsov VA Makshakov GG Ivanov AG Minaev EV Minaeva AG Perevozchikov MS Shirobokova VE Susekov VG Karpov VV Vozdvizhenski? 《Canadian Metallurgical Quarterly》1996,(2):37-38
The trend of the incidence of tick-borne encephalitis makes one pay attention to the production of blood biological preparations. A detailed programme for improving the production process, which is included into the federal and republican programmes, is outlined. 相似文献
563.
The effect of lovastatin, a competing inhibitor of 3-hydroxy-3-methylglutaryl-CoA-reductase (HMG-CoA-reductase) of the fungal origin on the growth of and ergosterol biosynthesis by Rh. rubra VKPM Y 1337 was studied. It was shown that the yeast growth was inhibited by lovastatin in concentrations of 0.25 to 5.0 micrograms/ml when the inhibitor was added to the cultivation medium either with the inoculum or at later periods of the yeast cultivation. In concentrations of 2.0 to 5.0 micrograms/ml lovastatin almost completely inhibited the yeast growth. In the concentrations tested the inhibitor did not decrease the ergosterol level in the yeast cells below 40 per cent of the control. When lovastatin was added in concentrations of 1.0 to 5.0 micrograms/ml the maximum inhibition of the ergosterol biosynthesis was observed at the end of the growth log phase. Further cultivation of the yeast in the presence of the inhibitor resulted in an increase of the ergosterol biosynthesis. It is believed that the increase in the quantity of ergosterol may be due either to the HMG-CoA-reductase induction under the action of the inhibitor or to its inactivation as a result of the hydroxylation. 相似文献
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566.
Theophylline salivary and serum concentrations (Tser and Tsal) were quantified after a single dose administration of theophylline drugs: euphylline (2.4% solution, 10 ml i.v. jet and 0.15 orally), theo-dur, retaphil, theopek, theobilong (0.3 g orally). The drugs were given to patients with broncho-obstructive syndrome. The samples were obtained within 6 and 24 hours upon administration for euphylline and other drugs, respectively. Tser and Tsal were determined at high-performance liquid chromatography. The authors revealed a linear relationship between Tser and Tsal in different time intervals. The percentage factors and formulas of Tser calculation by its Tsal values have been estimated. 相似文献
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569.
Progressive deterioration of left ventricular (LV) function is a characteristic feature of the heart failure (HF) state. The mechanism or mechanisms responsible for this hemodynamic deterioration are not known but may be related to progressive intrinsic dysfunction, degeneration and loss of viable cardiocytes. In the present study, we tested the hypothesis that accumulation of collagen in the cardiac interstitium (reactive interstitial fibrosis, RIF), known to occur in HF, results in reduced capillary density (CD = capillary/fiber ratio) and increased oxygen diffusion distance (ODD) which can lead to hypoxia and dysfunction of the collagen encircled myocyte. Studies were performed in LV tissue obtained from 10 dogs with chronic HF (LV ejection fraction 26 +/- 1%) produced by multiple sequential intracoronary microembolizations. In each dog, CD and ODD were evaluated in LV regions that manifested severe RIF (volume fraction 16 +/- 2%) and in LV regions of little or no RIF (volume fraction 4 +/- 1%). In regions of severe RIF, CD was significantly decreased compared to regions of no RIF (0.92 +/- 0.02 vs. 1.05 +/- 0.03) (P < 0.003). Similarly, ODD was significantly increased in regions of severe RIF compared to regions of no RIF (15.3 +/- 0.4 vs. 12.2 +/- 0.3 microns) (P < 0.001). These data suggest that in dogs with chronic HF, constituent myocytes of LV regions which manifest severe RIF may be subjected to chronic hypoxia; a condition that can adversely impact the function and viability of the collagen encircled cardiocyte. 相似文献
570.
By the step-by-step selection method energetically optimal conformation of double-stranded polynucleotides were calculated proceeding from the conformations of mono-and dinucleotides. These structures were found to belong to the families of DNA A and B forms. The dependence of six torsion angles of the polynucleotide chain on the glycosidic angle chi was investigated. As a result certain areas admitting of double-helix polynucleotides with sugar C3-endo with chi = -80 degrees were established. 相似文献