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1.
Article En | MEDLINE | ID: mdl-38551442

Background: Previous studies link overweight/obesity to reduced fertility, highlighting weight intervention as vital for better pregnancy outcomes. However, clarity on the role and efficacy of weight loss in enhancing pregnancy is inconsistent. Objective: This study aimed to assess the impact of individualized weight intervention on pregnancy among Chinese overweight/obese infertile women and explore body composition indexes influencing pregnancy outcomes. Methods: This retrospective study involved 363 overweight/obese infertile women admitted to the First Affiliated Hospital of Guangxi Medical University, Guangxi, China, from June 2017 to November 2020. Among them, 249 received personalized weight intervention (intervention group), while 114 did not (control group). Pregnancy outcomes were compared between the two groups, and changes in body composition before and after intervention were measured. Multivariate logistic regression was employed to analyze factors influencing pregnancy outcomes. Results: The intervention group exhibited significantly higher clinical pregnancy rates, natural pregnancy rates, assisted reproductive pregnancy rates, and induced ovulation (IO) pregnancy rates compared to the control group (all P < .05). Following weight intervention, there were significant decreases in body weight, body mass index (BMI), visceral fat area, and body fat (all P < .01). Logistic regression analysis identified polycystic ovary syndrome as the reason for infertility (OR=3.446, P = .016), ∆body weight %≥10% (OR=2.931, P = .014), and ∆visceral fat area% (OR=1.025, P = .047) as positive factors for a successful pregnancy. Conversely, age≥35 years old (OR=0.337, P = .001), BMI≥25 kg/m2 after intervention (OR=0.279, P < .001), and visceral fat area≥100 cm2 after intervention (OR=0.287, P = .007) were identified as negative factors. Conclusions: Individualized weight management enhances pregnancy outcomes in overweight/obese infertile women. Achieving a reduction in body weight by 10% or more, combined with effective control of visceral fat, proves important in improving pregnancy outcomes. Excess visceral fat emerges as an adverse factor impacting successful pregnancy.

2.
J Obstet Gynaecol Res ; 49(4): 1206-1213, 2023 Apr.
Article En | MEDLINE | ID: mdl-36738078

BACKGROUND: Both in vitro fertilization and embryo transfer (IVF-ET) and intracytoplasmic sperm injection and embryo transfer (ICSI-ET) have been recommended for unexplained primary infertility after recurrent artificial insemination with homologous semen failure (UAIHF), but few studies focused on the safety and efficiency of the IVF/ICSI-ET technique for these patients. In this study, we compared the IVF/ICSI-ET outcomes and perinatal and postnatal complications between UAIHF patients and tubal infertility (TI) patients. METHODS: We conducted a retrospective study of UAIHF and TI patients who underwent IVF/ICSI-ET at Guangxi Reproductive Medical Center, the First Affiliated Hospital of Guangxi Medical University from January 2012 to March 2021. After propensity score matching (PSM), we analyzed the IVF/ICSI-ET outcomes and rates of perinatal and postnatal complications. RESULTS: PSM analysis revealed that the baselines of age, infertility duration, and body mass index were comparable. The fertilization method was significantly different between the two groups. Through IVF/ICSI-ET, UAIHF patients had a similar clinical outcome compared to TI patients. Regarding perinatal and postnatal complications, the incidence of premature rupture of membranes (PROM) (7.54% vs. 3.17%, p = 0.030) was significantly higher in UAIHF patients. CONCLUSIONS: UAIHF patients could achieve satisfying pregnancy outcomes by IVF/ICSI-ET. ICSI-ET did not seem to improve the clinical outcomes of UAIHF patients compared to those of TI patients who underwent IVF-ET, which might be related to possible underlying diseases in these patients. In addition, the incidence of PROM was significantly higher in UAIHF patients, which might be related to the ICSI technique used and uncertain potential idiopathic diseases associated with unexplained infertility patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2200057572. Registered 15 March 2022.


Infertility , Sperm Injections, Intracytoplasmic , Female , Humans , Male , Pregnancy , China/epidemiology , Embryo Transfer , Fertilization in Vitro/methods , Insemination, Artificial , Pregnancy Rate , Prognosis , Retrospective Studies , Semen , Sperm Injections, Intracytoplasmic/methods
3.
Saudi J Biol Sci ; 27(4): 1049-1056, 2020 Apr.
Article En | MEDLINE | ID: mdl-32256165

In order to explore the predictive model for analyzing clinical pregnancy outcomes based on IVF-ET (in vitro fertilization and embryo transfer) and ICSI (Intracytoplasmic sperm injection) assisted reproductive technology (ART). METHODS: this study selected the embryo transfer (fresh) patients who received IVF-ET or ICSI treatment in the First Affiliated Hospital of Guangxi Medical University as the subjects. Moreover, the controlled ovarian stimulation (COS) and follow-up were conducted to collect relevant data for analysis, and finally a prediction model was established. RESULTS: The results showed that the patients were divided into different ovarian response groups at first. The age, bFSH and bFSH/bLH were the highest in the poor ovarian response group (POR), followed by the normal ovarian response group (NOR) and the lowest in the high ovarian response group (HOR). The area under the ROC curve was 0.669 according to the predictive model of pregnancy-related factors. The confidence interval of 94% was 0.629-0.697, with statistical significance (P = 0.000, P < 0.01). CONCLUSION: it can be concluded that in clinical pregnancy, for many related factors, regression equation can be used to establish a prediction model to diagnose the success rate of pregnancy. In conclusion, a prediction model can be built based on the relevant experimental results, to provide experimental reference ideas for increasing the success rate of ART in late clinical pregnancy, which is of great research significance.

4.
Gynecol Endocrinol ; 35(1): 17-22, 2019 Jan.
Article En | MEDLINE | ID: mdl-30303701

PURPOSES: Nowadays, an increasing number of studies have proposed single embryo transfer (SET), especially single blastocyst transfer (SBT). To compare the clinical outcomes of single fresh blastocyst transfer (BT) and single cryopreserved-thawed BT in patients undergoing in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles. METHODS: The PubMed, Embase, and Cochrane Library databases were searched from the start dates until February 2018. The primary outcomes were clinical pregnancy rate (CPR) and embryo implantation rate (IR). The secondary outcomes were multiple pregnancy rate (MPR), live birth rate (LBR), and miscarriage rate (MR). Using the Mantel-Haenszel random effects model to analyze summary risk ratio (RR) with 95% confidence intervals (CIs). Statistical heterogeneity scores were assessed with the standard Cochrane's Q test and I2 statistic. RESULTS: In total, eight studies (two prospective studies, six retrospective studies) were included in our analysis. There was no statistically significant difference regarding clinical pregnancy (RR = 1.18, 95% CI = 0.91-1.55) and embryo implantation (RR = 1.04, 95% CI = 0.77-1.41). Regarding secondary outcomes, there was no significant difference regarding miscarriage (RR = 0.79, 95% CI = 0.60-1.03) and multiple pregnancy (RR = 1.23, 95% CI = 0.75-2.04). However, single fresh BT is associated with an increased live birth (RR = 1.28, 95% CI = 1.05-1.57) compared with single cryopreserved-thawed BT. CONCLUSIONS: In summary, this meta-analysis supports the hypothesis that single cryopreserved BT might not be the best choice compared with single fresh BT in patients undergoing IVF/ICSI cycles.


Embryo Transfer/methods , Fertilization in Vitro/methods , Infertility/therapy , Sperm Injections, Intracytoplasmic/methods , Female , Humans , Pregnancy , Pregnancy Outcome , Pregnancy Rate , Treatment Outcome
5.
J Assist Reprod Genet ; 35(1): 127-134, 2018 Jan.
Article En | MEDLINE | ID: mdl-28940130

OBJECTIVE: This systematic review sought to evaluate the clinical outcomes of vitrification at the cleavage stage and blastocyst stage for embryo transfer in patients undergoing assisted reproductive technology (ART) treatment. METHODS: We searched for related comparative studies published in the PubMed, EMBASE, and Cochrane Library databases up to July 2017. The primary outcomes were clinical pregnancy rate (CPR) and embryo implantation rate (IR). Secondary outcomes were multiple pregnancy rate (MPR), miscarriage rate (MR), live birth rate (LBR), and ongoing pregnancy rate (OPR). The Mantel-Haenszel fixed effects model and random effects model were used to analyze the summary risks ratios (RRs) with 95% confidence intervals (CIs). RESULTS: Eight studies with more than 6590 cycles were included in our meta-analysis. Seven studies were observational retrospective comparative studies. One was a prospective study. Overall, the current study summarizes information from 6590 vitrification warming cycles (cleavage stage n = 4594; blastocysts n = 1996). There was no difference in the primary outcome clinical pregnancy rate (RR = 0.97, 95% CI = 0.90-1.04; fixed effects model; I 2  = 21%), whereas vitrified blastocyst transfer was significantly superior to vitrified cleavage-stage embryo transfer regarding the implantation rate (RR = 0.85, 95% CI = 0.74-0.97; random effects model; I 2  = 43). Regarding the secondary outcomes, no differences were found in the multiple pregnancy rate (RR = 1.20, 95% CI = 0.79-1.82; fixed effects model; I 2  = 22), live birth rate (RR = 1.07, 95% CI = 0.98-1.16; fixed effects model; I 2  = 0), and ongoing pregnancy rate (RR = 1.01, 95% CI = 0.92-1.120; fixed effects model; I 2  = 0), whereas a higher miscarriage rate was observed with vitrified blastocyst transfer (RR = 0.65, 95% CI = 0.45-0.93; random effects model; I 2  = 23). CONCLUSION: In summary, this meta-analysis shows that vitrification at any stage has no detrimental effect on clinical outcome. Blastocyst transfer will still remain a favorable and promising option in ART. Due to the small sample evaluated in the pool of included studies, large-scale, prospective, and randomized controlled trials are required to determine if these small effects are clinically relevant.


Blastocyst , Cleavage Stage, Ovum/physiology , Embryo Transfer , Pregnancy Outcome , Vitrification , Embryo Transfer/methods , Embryo Transfer/statistics & numerical data , Female , Humans , Observational Studies as Topic/statistics & numerical data , Pregnancy , Pregnancy Rate , Retrospective Studies
6.
Lasers Med Sci ; 33(3): 655-666, 2018 Apr.
Article En | MEDLINE | ID: mdl-29116610

It is well known that laser-assisted hatching (LAH) is the most popular and ideal embryo hatching technology, but the relevance to pregnancy outcomes of cryopreserved-thawed embryo transfer (ET) is controversial. The purpose of this meta-analysis was to evaluate the effects of LAH on pregnancy outcomes of cryopreserved-thawed ET. We searched for relevant studies published in the PubMed, EMBASE, and Cochrane Central databases up to March 2017. This meta-analysis was primarily used to evaluate the effect of laser-assisted hatching on assisted reproductive outcomes: clinical pregnancy, embryo implantation, multiple pregnancy, miscarriage, and live birth. Using the Mantel-Haenszel fixed effects model and random effects model, we determined the summary odds ratios (OR) with 95% confidence intervals (CIs). There were 12 randomized controlled trials (more than 2574 participants) included in our analysis. The rates of clinical pregnancy (OR = 1.65, 95% CI = 1.24-2.19, I 2 = 49), implantation (OR = 1.59, 95% CI = 1.06-2.38, I 2 = 82%), multiple pregnancy (OR = 2.30, 95% CI = 1.30-4.07, I 2 = 33%), miscarriage (OR = 0.86, 95% CI = 0.50-1.48, I 2 = 0%), and live birth (OR = 1.09, 95% CI = 0.77-1.54, I 2 = 0%) revealed comparable results for both groups. In summary, this meta-analysis demonstrates that LAH is related to a higher clinical pregnancy rate, embryo implantation rate, and multiple pregnancy rate in women with cryopreserved-thawed embryos. However, LAH is unlikely to increase live birth rates and miscarriage rates. Due to the small sample evaluated in the pool of included studies, large-scale, prospective, randomized, controlled trials are required to determine if these small effects are clinically relevant.


Cryopreservation , Embryo Transfer , Lasers , Pregnancy Outcome , Randomized Controlled Trials as Topic , Abortion, Spontaneous/epidemiology , Embryo Implantation/radiation effects , Female , Humans , Live Birth/epidemiology , Pregnancy , Pregnancy Rate , Pregnancy, Multiple , Prospective Studies , Publications
7.
Int J Gynaecol Obstet ; 131(3): 240-5, 2015 Dec.
Article En | MEDLINE | ID: mdl-26421833

BACKGROUND: Evidence for the efficacy of dehydroepiandrosterone (DHEA) in improving ovarian responsiveness among poor responders, especially women with diminished ovarian reserve (DOR), remains inconsistent. OBJECTIVES: To evaluate the effectiveness of DHEA in women with DOR undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). SEARCH STRATEGY: PubMed and Embase were searched for reports published in any language before October 31, 2014, using keywords such as "DHEA," "poor ovarian response," "diminished ovarian reserve," and "premature ovarian aging." SELECTION CRITERIA: Studies that explored the effects of DHEA in women with DOR undergoing IVF/ICSI were included if they evaluated the number of oocytes retrieved and/or the rates of clinical pregnancy, implantation, and spontaneous abortion. DATA COLLECTION AND ANALYSIS: Risk ratios (RRs) and standardized mean differences with 95% confidence intervals (CIs) were calculated, combined with subgroup and sensitivity analyses. MAIN RESULTS: Eight studies were included. The use of DHEA increased the clinical pregnancy rate (RR 2.13; 95% CI 1.12-4.08). Similar results were obtained in subgroup analyses including randomized controlled trials and case-control studies (RR 2.57; 95% CI 1.43-4.63) and self-controlled studies (RR 3.95; 95% CI 1.28-12.19). However, the effects of DHEA on oocyte retrieval, implantation, and abortion were not significant. CONCLUSIONS: Supplementation with DHEA has a positive effect in women undergoing IVF/ICSI treatment for DOR.


Dehydroepiandrosterone/administration & dosage , Fertilization in Vitro/methods , Sperm Injections, Intracytoplasmic/methods , Female , Humans , Ovarian Reserve/physiology , Pregnancy , Pregnancy Rate , Randomized Controlled Trials as Topic
8.
J Assist Reprod Genet ; 32(5): 817-25, 2015 May.
Article En | MEDLINE | ID: mdl-25862345

BACKGROUND: FXIII Val34Leu (rs5985) and ß-fibrinogen -455G/A (rs1800790) genotypes have been reported to be associated with recurrent spontaneous abortion (RSA). However, this topic is controversial. This study aimed to explore whether FXIII Val34Leu or ß-fibrinogen -455G/A gene polymorphisms are related to RSA. METHODS: In this analysis, PubMed, HuGENet and Chinese National Knowledge Infrastructure (CNKI) databases were reviewed. Four models including the dominant model (Val/Val+Val/Leu vs. Leu/Leu), recessive model (Val/Val vs Val/Leu + Leu/Leu), co-dominant model (Val/Val vs. Val/Leu, Val/Val vs. Leu/Leu) and per-allele analysis (Val vs. Leu) were applied. The odds ratio (OR) with 95% confidence interval (CI) was used to assess the association between RSA and FXIII Val34Leu and ß-fibrinogen -455G/A polymorphisms. RESULTS: Nine studies with 10 sets of data were included according to the inclusion criterion. A positive association was detected in the pooled results for the dominant model (Val/Val+Val/Leu vs. Leu/Leu; OR = 0.417, 95% CI: 0.180-0.965, I(2) = 45.60%) and co-dominant model (Val/Val vs. Val/Leu; OR = 0.638, 95% CI: 0.452-0.899, I(2) = 36.40%) for FXIII Val34Leu polymorphisms. However, no statistically significant association between ß-fibrinogen -455G/A polymorphisms and RSA was detected in the four different models, including the Asian and Caucasian subgroup analyses. CONCLUSIONS: Our meta-analysis demonstrates that the FXIII Val34Leu polymorphism has a close association with RSA and women who carry the Val allele for the FXIII Val34Leu polymorphism could have a protective effect against RSA. However, no association is detected between ß-fibrinogen -455G/A polymorphisms and the risk of RSA. Future well-designed studies are needed to confirm these results.


Abortion, Habitual/genetics , Abortion, Spontaneous/genetics , Factor XIII/genetics , Polymorphism, Genetic/genetics , Case-Control Studies , Female , Humans , Prognosis , Risk Factors
9.
Ann Hum Genet ; 78(2): 104-16, 2014 Mar.
Article En | MEDLINE | ID: mdl-24308758

A relationship between endometriosis and tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) gene polymorphisms has been raised for Asians. However, this topic is controversial. This study was a meta-analysis to explore whether TNF-α/IL-6 gene polymorphisms were associated with a risk of endometriosis in Asians. By searching PubMed, HuGENet, and China National Knowledge Infrastructure (CNKI) databases, 17 studies were identified and included (3372 cases and 4008 controls). The odds ratio (OR) with 95% confidence interval (CI) was used to assess the association between TNF-α/IL-6 gene polymorphisms and endometriosis risk. An association of TNF-α gene -1031T/C polymorphism with endometriosis was found (TT + TC vs. CC: OR 0.50, 95% CI 0.30-0.82, I(2) = 37.1%, P = 0.20; TT vs. CC: OR 0.50, 95% CI 0.30-0.82, I(2) = 43.0%, P = 0.173; TC vs. CC: OR 0.49, 95% CI 0.29-0.83, I(2) = 10.6%, P = 0.327). In addition, TNF-α-238A/G and IL-6 -174C/G gene polymorphisms were also likely to be associated with endometriosis in Asians. For the TNF-α-238A/G gene polymorphism, the OR was 1.577 (95% CI: 1.01-2.48). For the IL-6 -174C/G gene polymorphism, the OR was 1.554 (95% CI: 1.04-2.31). No associations were detected between the TNF-α-308A/G and IL-6 -634C/G polymorphisms and susceptibility to endometriosis. Our results indicate that the TNF-α gene -1031T/C polymorphism can reduce the risk of endometriosis, but for Asians, TNF-α-238A/G and IL-6 -174C/G gene polymorphisms may be a risk factor for endometriosis. No association was found for the TNF-α-308A/G and IL-6 -634C/G gene polymorphisms.


Asian People/genetics , Endometriosis/genetics , Interleukin-6/genetics , Polymorphism, Single Nucleotide , Tumor Necrosis Factor-alpha/genetics , China , Female , Genetic Predisposition to Disease , Humans
10.
J Assist Reprod Genet ; 31(2): 139-48, 2014 Feb.
Article En | MEDLINE | ID: mdl-24221911

BACKGROUND: Recently, a relationship between recurrent pregnancy loss (RPL) and Apolipoprotein E (Apo E) gene polymorphisms has been proposed. In order to investigate the real association between Apo E polymorphisms and RPL, our meta-analysis was carried out. METHODS: We estimated the association with RPL risk under dominant and recessive models, in combination with the OR and RR with a 95% confidence interval (CI), which was used to assess the association between RPL and Apo E polymorphisms. RESULTS: According to our criterion, there were 6 studies included. The dominant model used the E4/E3 group and the OR was 1.919 (95 %CI: 1.016-3.625, I(2) = 53.8%), the RR was 1.308 (95%Cl: 1.071-1.598) suggesting that carriers of the E4 allele would have a higher risk of causing spontaneous miscarriages. In addition, the OR was 0.727 (95%CI: 0.566-0.932, I(2) = 0.0%) and RR was 0.923 (95%CI: 0.867-0.982) in a fixed model for E3/E3 homozygotes versus other genotypes, suggesting that the Apo E3 polymorphism could be a protective factor. The OR was 1.365 (95% CI: 1.029-1.811, I(2) = 0 .0%) in a fixed model comparing the E2 allele with the E3 allele, suggesting that Apo E2 polymorphisms may contribute to RPL as a risk factor. Furthermore, after conducting sensitivity analysis in the E4/E3 group, the results showed this to be consistent and the OR was 2.249 (95%CI: 1.474-3.431). CONCLUSIONS: There is a close association between RPL and Apo E gene polymorphisms. For RPL, the Apo E4 polymorphism could be a risk factor, the Apo E3 polymorphism may be a protective factor and the Apo E2 polymorphism may be another potential risk factor.


Abortion, Habitual/genetics , Apolipoproteins E/genetics , Polymorphism, Genetic , Female , Homozygote , Humans , Models, Genetic , Pregnancy
11.
Am J Reprod Immunol ; 70(6): 434-47, 2013 Dec.
Article En | MEDLINE | ID: mdl-24238107

Intravenous immunoglobulin (IVIG) has been introduced empirically into IVF/ICSI programs with the hopes of improving in vitro fertilization (IVF) success. However, the effects of IVIG have been inconsistent. We investigated the effects of IVIG on hard outcomes, including implantation rate, clinical pregnancy rate, live birth rate, miscarriage rate, and live birth rate per embryo transferred. The PubMed, EMBASE, and CNKI databases were searched up to June of 2013 and 10 studies were included. Case-controlled studies comparing IVIG with placebo in IVF/ICSI women and/or unexplained infertility were included. Using fixed and random effects models, the pooled risk ratios (RR) with 95% confidence intervals (CIs) were calculated. The use of IVIG was significantly associated with a higher implantation rate and RR was 2.708 (95%CI: 1.302-5.629) compared with the placebo. The clinical pregnancy rate and the live birth rate were significantly increased in patients randomized to IVIG; RR was 1.475 (95%CI: 1.191-1.825) for the clinical pregnancy rate and RR was 1.616 (95%CI: 1.243-2.101) for the live birth rate. Moreover, the miscarriage rate was significantly less in patients randomized to IVIG (0.352, 95%CI: 0.168-0.738), but the live birthrate per embryo transferred was not (2.893; 95%CI: 0.810-10.331) less. Our results strongly support that IVIG is a useful treatment option for women undergoing repeated IVF failure.


Fertilization in Vitro/methods , Immunoglobulins, Intravenous/immunology , Immunoglobulins, Intravenous/therapeutic use , Infertility/immunology , Embryo Implantation/drug effects , Embryo Implantation/immunology , Female , Humans , Immunoglobulins, Intravenous/administration & dosage , Infertility/drug therapy
12.
Zhonghua Nan Ke Xue ; 17(5): 418-21, 2011 May.
Article Zh | MEDLINE | ID: mdl-21837951

OBJECTIVE: To evaluate the results of requesting a second consecutive sperm ejaculate in order to reduce ICSI cycles by PESA or TESE on the day of oocyte pick-up in assisted reproductive technology (ART). METHODS: We collected 68 semen samples as a second consecutive ejaculate from 34 men, compared the semen volume and sperm concentration, motility and total count between the first and the second ejaculation, and analyzed the laboratory results and clinical outcomes of fertilization with the mixed sperm. RESULTS: The 34 males ejaculated twice within 4 hours by masturbation, with an interval of 26-183 (94.9 +/- 39.8) minutes between the first and second ejaculation. The volume of the first ejaculate was (2.0 +/- 1.4) ml, significantly higher than that of the second ([1.5 +/- 0.9] ml) (P = 0.007), although the numbers of motile sperm and grade a + b sperm of the first ([40.8 +/- 25.3]% and [30.9 +/- 22.4]%) were significantly lower than those of the second ([52.2 +/- 21.1]% and [39.9 +/- 17.5]%) (P < 0.05). There were no statistically significant differences in the sperm concentration or total sperm count between the two ejaculates (P > 0.05). The ICSI, IVF + ICSI, and IVF cycles were 3, 3 and 28 respectively among the 34 couples undergoing ART. The number of retrieved oocytes, normal fertilization rate, high quality embryo rate and frozen cycles/fresh transfer cycles ratio were 15.5 +/- 8.7, 57.0% (247/433), 58.7% (145/247) and 20/24 for the IVF cycle, 21.7 +/- 8.3, 61.5% (40/65), 67.5% (27/40) and 3/2 for the ICSI cycle, and 10.0 +/- 2.6, 72.4% (21/29), 66.7% (14/21) and 3/3 for the IVF + ICSI cycle. Fourteen live births were achieved out of the 18 pregnancies, including 6 healthy boys and 9 healthy girls. CONCLUSION: A clinical pregnancy rate of >30% can be achieved by requesting a second consecutive sperm ejaculate on the day of oocyte pick-up in order to collect more sperm and/or increase the total number of motile sperm for ART. And this method can avoid other invasive sperm processing techniques and the need of unnecessary micromanipulative fertilization.


Reproductive Techniques, Assisted , Sperm Retrieval , Adult , Female , Humans , Male , Middle Aged , Ovulation Induction , Pregnancy , Young Adult
13.
J Chem Phys ; 120(21): 10025-32, 2004 Jun 01.
Article En | MEDLINE | ID: mdl-15268023

Photoinduced electron transfer of the model system composed of vitamin E and duroquinone has been investigated using time-dependent density functional theory. Calculations for the excited states tell that the photoexcitation of the model system can directly yield the charge transfer states in which the vitamin E moiety is positively charged but the duroquinone moiety is negatively charged. Our theoretical investigations indicate that the second charge transfer state of the model system can also be produced through the decay of higher locally excited state S(4). Since S(4) state in the model system corresponds to S(1) state of the isolated duroquinone used as a model for peroxyl radical, and S(2) state has the character of electron transfer from the tertiary amine group of the vitamin E moiety to the duroquinone moiety, the decay from S(4) to S(2) corresponds to the dynamic process following the photoexcitation of the duroquinone moiety of the model system, i.e., the initial stage of antioxidant reaction of vitamin E. Calculations of the kinetic parameters for the electron transfer have been carried out in the framework of the Marcus-Jortner-Levich formalism. Our calculations confirm that the electron transfer from S(4) to S(2) possesses the character of the inverted regime and the barrier is negligibly small.


Benzoquinones/chemistry , Benzoquinones/radiation effects , Light , Models, Chemical , Models, Molecular , Photochemistry/methods , Vitamin E/chemistry , Vitamin E/radiation effects , Computer Simulation , Electron Transport/radiation effects , Kinetics , Time Factors
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