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排序方式: 共有195条查询结果,搜索用时 15 毫秒
1.
Dipak K. Das Richard M. Engelman Xuekun Liu Swapna Maity John A. Rousou Joseph Flack Jitendra Laksmipati Randall M. Jones M. Renuka Prasad David W. Deaton 《Molecular and cellular biochemistry》1992,111(1-2):77-86
Reperfusion injury occurs during open-heart surgery after prolonged cardioplegic arrest. Cardiopulmonary bypass also is known to cause hemolysis. Since reperfusion of ischemic myocardium is associated with the generation of oxygen free radicals, and since free radicals can attack a protein molecule, it seems reasonable to assume that hemolysis might be the consequence of free radical attack on hemoglobin protein. The results of this study demonstrated that reperfusion following ischemic arrest caused an increase in free hemoglobin and free heme concentrations, simultaneously releasing free iron and generating hydroxyl radicals. In vitro studies using pure hemoglobin indicated that superoxide anion generated by the action of xanthine oxidase on xanthine could release iron from the heme ring and cause deoxygenation of oxyhemoglobin into ferrihemoglobin. This study further demonstrated that before the release of iron from the heme nucleus, oxyhemoglobin underwent deoxygenation to ferrihemoglobin. The released iron can catalyze the Fenton reaction, leading to the formation of cytotoxic hydroxyl radical (OH·). In fact, the formation of OH. in conjunction with hemolysis occurs during cardiac surgery, and when viewed in the light of the in vitro results, it seems likely that oxygen-derived free radicals may cause hemolysis during cardiopulmonary bypass and simultaneously release iron from the heme ring, which can catalyze the formation of OH·. 相似文献
2.
M. Renuka Prasad H. S. Dhillon T. Carbary R. J. Dempsey S. W. Scheff 《Journal of neurochemistry》1994,63(2):773-776
Abstract: Regional levels of lactate and inositol 1,4,5-trisphosphate (IP3 ), a cellular second messenger of the excitatory neurotransmitter system, were measured after lateral fluid percussion (FP) brain injury in rats. At 5 min postinjury, tissue lactate concentrations were significantly elevated in the cortices and hippocampi of both the ipsilateral and contralateral hemispheres. By 20 min postinjury, lactate concentrations were elevated only in the cortices and hippocampus of the ipsilateral hemisphere. Whereas the IP3 concentrations were elevated in the hippocampi of the ipsilateral and contralateral hemisphere and in the cortex of ipsilateral hemisphere at 5 min postinjury, no elevation in these sites was found at 20 min postinjury. Histologic analysis revealed neuronal damage in the cortex and CA3 regions of hippocampus ipsilateral to the injury at 24 h postinjury. The present results suggest activation of the phosphoinositide signal transduction pathway at the onset of injury and of a possible requirement of early persistent metabolic dysfunction (>20 min) such as the lactate accumulation in the delayed neuronal damage. 相似文献
3.
Choudhary Renuka Sharma Anil Kumar Sudarshan Upadhyay Ramesh Chandra Singh Sohan Vir Mohanty Ashok 《Molecular and cellular biochemistry》2020,465(1-2):141-153
Molecular and Cellular Biochemistry - Ultraviolet radiations (UVR) are responsible for a wide variety of acute and chronic effects on the animal skin. However, the effect of UVR-induced oxidative... 相似文献
4.
A. B. Shreya Renuka S. Managuli Jyothsna Menon Lavanya Kondapalli Aswathi R. Hegde Kiran Avadhani 《Journal of liposome research》2016,26(3):221-232
Context: Asenapine maleate (ASPM) is an antipsychotic drug for the treatment of schizophrenia and bipolar disorder. Extensive metabolism makes the oral route inconvenient for ASPM.Objective: The objective of this study is to increase ASPM bioavailability via transdermal route by improving the skin permeation using combined strategy of chemical and nano-carrier (transfersomal) based approaches.Materials and methods: Transfersomes were prepared by the thin film hydration method using soy-phosphatidylcholine (SPC) and sodium deoxycholate (SDC). Transfersomes were characterized for particle size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, surface morphology, and in vitro skin permeation studies. Various chemical enhancers were screened for skin permeation enhancement of ASPM. Optimized transfersomes were incorporated into a gel base containing suitable chemical enhancer for efficient transdermal delivery. In vivo pharmacokinetic study was performed in rats to assess bioavailability by transdermal route against oral administration.Results and discussion: Optimized transfersomes with drug:SPC:SDC weight ratio of 5:75:10 were spherical with an average size of 126.0?nm, PDI of 0.232, ZP of??43.7?mV, and entrapment efficiency of 54.96%. Ethanol (20% v/v) showed greater skin permeation enhancement. The cumulative amount of ASPM permeated after 24?h (Q24) by individual effect of ethanol and transfersome, and in combination was found to be 160.0, 132.9, and 309.3?μg, respectively, indicating beneficial synergistic effect of combined approach. In vivo pharmacokinetic study revealed significant (p?0.05) increase in bioavailability upon transdermal application compared with oral route.Conclusion: Dual strategy of permeation enhancement was successful in increasing the transdermal permeation and bioavailability of ASPM. 相似文献
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The purpose of this study was to determine the factors that influence fill weight and weight variability of capsules produced
on the In-Cap and to assess any differences in terms of capsule defects between gelatin and HPMC (Quali-V) shells. The In-Cap
is an automatic tamping type capsule-filling machine and the low output of ≈3000 capsules/hour makes it ideal for early formulation
development and phase I/IIa clinical supplies manufacture. Four commonly used excipients (Avicel PH101, Avicel PH302, A-Tab,
and Prosolv HD90) and a poorly flowing drug blend were encapsulated at various pin settings and powder bed heights. The average
fill weight and coefficient of weight variation were determined. The percentage of defective capsules formed during encapsulation
was calculated. Results of the study showed that pin setting was critical for controlling the fill weight and the weight variation.
The order of pin setting with pin 1 (closer to the powder chute) set to a relatively higher position and pin 4 (before ejection)
set to a lower position was found to give higher fill weights with relatively lower weight variability. The powder bed height
influenced the fill weight for poorly flowing powders. The capsule machine speed did not appear to significantly influence
the fill weight. The fill weight and weight variation were found to depend on the flow property of the material. A large percentage
of defective capsules was obtained using HPMC shell size #00. Some of the commonly observed defects included split caps and
improperly closed filled capsules. In general, appropriate selection of pin settings and bed height can reduce the weight
variability seen, especially with poorly flowing high-dose formulations. 相似文献
8.
Sharma VM Prasanna P Seshu KV Renuka B Rao CV Kumar GS Narasimhulu CP Babu PA Puranik RC Subramanyam D Venkateswarlu A Rajagopal S Kumar KB Rao CS Mamidi NV Deevi DS Ajaykumar R Rajagopalan R 《Bioorganic & medicinal chemistry letters》2002,12(17):2303-2307
In our endeavor to design and synthesize novel anticancer agents, a new series of indoloquinazoline compounds were prepared and tested initially for anticancer activity in vitro against a panel of human cancer cell lines. Most of these compounds exhibited cytotoxic activity in in vitro screens. Compounds were selected and further evaluated using a modified Hollow Fiber Assay for their preliminary in vivo activity against 12 cell lines implanted in the subcutaneous and intraperitoneal compartments in mice. The results indicate that these compounds may constitute a new class of anticancer agents. 相似文献
9.
The beneficial effects of magnesium supplementation in pathological situations is well known, but the myocardial response
to a nominal decrease in the level of magnesium has received relatively little attention. Hypomagnesemia can occur as chronic
or acute manifestation of physiological changes, pathological conditions, or pharmacological interventions. Experimental interest
was focused on the mechanical changes in adult rat heart myocytes following variation in extracellular Mg2+. Isolated cells were exposed to different levels of extracellular Mg2+ and the amplitude and rate of contraction were measured as a function of change in cell length using a video-based edge-detection
system. Investigations have revealed that variation in the level of Mg2+ within physiological limits leads to mechanical changes. A decrease in the level of extracellular Mg2+ was accompanied by a significant increase in contractile amplitude and decrease in the velocities of contraction and relaxation.
The contractile amplitude measured as percentage shortening were 3.08 ± 0.19%, 4.62 ± 0.19% and 6.9 ± 0.40%, respectively,
on exposure to 1.8, 0.8, and 0.48 mM Mg, and the corresponding velocities of contraction and relaxation normalized to amplitude were 0.54 ± 0.02, 0.40 ± 0.03,
0.31 ± 0.03 and 0.47 ± 0.02, 0.35 ± 0.02, 0.24 ± 0.02. The variations in contractile parameters associated with the change
in the level of Mg were statistically significant (p < 0.01). Variation in the contractile properties associated with change in extracellular Mg2+ may be effected by alteration in Ca2+ transients. 相似文献
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