Utility and limitations of perimortem cesarean section: A nationwide survey in Japan.

AIM: Perimortem cesarean section (PCS) is a procedure performed as part of cardiopulmonary resuscitation (CPR). This study aims to clarify maternal and neonatal prognosis and establish PCS's utility and limitations. METHODS: We sent structured questionnaires to obstetrics facilities regarding the cases of PCS performed in Japan between April 2010 and April 2015. Receiver operating characteristic (ROC) curve was used to determine the optimal cut-off values of the time from cardiopulmonary arrest (CPA) to return of spontaneous circulation to predict the onset of disseminated intravascular coagulation (DIC). RESULTS: PCS was performed for 18 patients. Out of 18 patients, 12 were resuscitated. The women who were discharged without major sequelae (n = 6) were compared with the non-discharged women who were dead or in persistent vegetative state (n = 12), and median interval time from arrest to PCS was significantly shorter in the former group (P = 0.002). Median interval time from CPA to PCS in the cases in which the neonates survived without major morbidities was significantly shorter than that in the cases of neonatal death and hypoxic encephalopathy (P = 0.01). DIC was observed in 8/9 (89%) patients whose resuscitation took more than 20 min from the diagnosis of CPA. Percutaneous cardiopulmonary support (PCPS) was introduced in 4/9 patients. However, more cases with uncontrolled bleeding, possibly caused by a sudden increase in blood flow and DIC after resuscitation, were observed in the PCPS group compared to the non-PCPS group. CONCLUSION: PCS can be an effective CPR procedure. However, if PCS is not performed within 20 min from CPA, starting PCPS before PCS is an option.

Correlation among Singlet-Oxygen Quenching, Free-Radical Scavenging, and Excited-State Intramolecular-Proton-Transfer Activities in Hydroxyflavones, Anthocyanidins, and 1-Hydroxyanthraquinones.

Singlet-oxygen (1O2) quenching, free-radical scavenging, and excited-state intramolecular proton-transfer (ESIPT) activities of hydroxyflavones, anthocyanidins, and 1-hydroxyanthraquinones were studied by means of laser, stopped-flow, and steady-state spectroscopies. In hydroxyflavones and anthocyanidins, the 1O2 quenching activity positively correlates to the free-radical scavenging activity. The reason for this correlation can be understood by considering that an early step of each reaction involves electron transfer from the unfused phenyl ring (B-ring), which is singly bonded to the bicyclic chromen or chromenylium moiety (A- and C-rings). Substitution of an electron-donating OH group at B-ring enhances the electron transfer leading to activation of the 1O2 quenching and free-radical scavenging. In 3-hydroxyflavones, the OH substitution at B-ring reduces the activity of ESIPT within C-ring, which can be explained in terms of the nodal-plane model. As a result, the 1O2 quenching and free-radical scavenging activities negatively correlate to the ESIPT activity. A catechol structure at B-ring is another factor that enhances the free-radical scavenging in hydroxyflavones. In contrast to these hydroxyflavones, 1-hydroxyanthraquinones having an electron-donating OH substituent adjacent to the O-H---O═C moiety susceptible to ESIPT do not show a simple correlation between their 1O2 quenching and ESIPT activities, because the OH substitution modulates these reactions.

Site-Specific Electron-Relaxation Caused by Si:2p Core-Level Photoionization: Comparison between F3SiCH2CH2Si(CH3)3 and Cl3SiCH2CH2Si(CH3)3 Vapors by Means of Photoelectron Auger Electron Coincidence Spectroscopy.

Site-specific electron relaxations caused by Si:2p core-level photoionizations in F3SiCH2CH2Si(CH3)3 and Cl3SiCH2CH2Si(CH3)3 vapors have been studied by means of the photoelectron Auger electron coincidence spectroscopy. F3SiCH2CH2Si(CH3)3 shows almost 100% site-specificity in fragmentation caused by the Si:2p ionization. However, substitution of Cl for F of F3SiCH2CH2Si(CH3)3 considerably reduces the site-specificity at the Si atom bonded to three halogen atoms, with the site-specificity at the Si site bonded to three methyl groups remaining largely unchanged. The site-specificity reduction in Cl3SiCH2CH2Si(CH3)3 is considered to take place during the transient period between Si:L23VV Auger electron emission and the subsequent fragmentation. The reason for the reduction can be explained in terms of some differences between these two molecules in the L23VV Auger decay at the Si site bonded to the three halogen atoms.

Pyrroloquinoline quinone (PQQ) is reduced to pyrroloquinoline quinol (PQQH2) by vitamin C, and PQQH2 produced is recycled to PQQ by air oxidation in buffer solution at pH 7.4.

Measurements of the reaction of sodium salt of pyrroloquinoline quinone (PQQNa2) with vitamin C (Vit C) were performed in phosphate-buffered solution (pH 7.4) at 25 °C under nitrogen atmosphere, using UV-vis spectrophotometry. The absorption spectrum of PQQNa2 decreased in intensity due to the reaction with Vit C and was changed to that of pyrroloquinoline quinol (PQQH2, a reduced form of PQQ). One molecule of PQQ was reduced by two molecules of Vit C producing a molecule of PQQH2 in the buffer solution. PQQH2, thus produced, was recycled to PQQ due to air oxidation. PQQ and Vit C coexist in many biological systems, such as vegetables, fruits, as well as in human tissues. The results obtained suggest that PQQ is reduced by Vit C and functions as an antioxidant in biological systems, because it has been reported that PQQH2 shows very high free-radical scavenging and singlet-oxygen quenching activities in buffer solutions.

Kinetic study of the quenching reaction of singlet oxygen by seven rice bran extracts in ethanol solution. Development of a singlet oxygen absorption capacity (SOAC) assay method.

Measurements of singlet oxygen ((1)O2) quenching rates (kQ (S)) and the relative singlet oxygen absorption capacity (SOAC) values were performed for seven rice bran extracts 1-7, which contained different concentrations of antioxidants (AOs) (such as α-, ß-, γ-, and δ-tocopherols and -tocotrienols, three carotenoids (lutein, ß-carotene, and zeaxanthin), and γ-oryzanol), in ethanol at 35 °C using UV-vis spectrophotometry. The concentrations of four tocopherols and four tocotrienols, three carotenoids, and γ-oryzanol contained in the extracts were determined using HPLC-MS/MS, UV-HPLC, and UV-vis absorption spectroscopy, respectively. Furthermore, comparisons of kQ (S) (Obsd.) values observed for the above extracts 1-7 with the sum of the product {[Formula: see text] [AO-i]} of the [Formula: see text] values obtained for each AO-i and the concentration ([AO-i]) of AO-i contained in extracts 1-7 were performed. From the results, it has been ascertained that the SOAC method is applicable to general food extracts to evaluate their (1)O2-quenching activity.

Kinetic study of the quenching reaction of singlet oxygen by α-, ß-, γ-, δ-tocotrienols, and palm oil and soybean extracts in solution.

Measurements of the singlet oxygen ((1)O2) quenching rates (kQ (S)) and the relative singlet oxygen absorption capacity (SOAC) values were performed for 11 antioxidants (AOs) (eight vitamin E homologues (α-, ß-, γ-, and δ-tocopherols and -tocotrienols (-Tocs and -Toc-3s)), two vitamin E metabolites (α- and γ-carboxyethyl-6-hydroxychroman), and trolox) in ethanol/chloroform/D2O (50:50:1, v/v/v) and ethanol solutions at 35 °C. Similar measurements were performed for five palm oil extracts 1-5 and one soybean extract 6, which included different concentrations of Tocs, Toc-3s, and carotenoids. Furthermore, the concentrations (wt%) of Tocs, Toc-3s, and carotenoids included in extracts 1-6 were determined. From the results, it has been clarified that the (1)O2-quenching rates (kQ (S)) (that is, the relative SOAC value) obtained for extracts 1-6 may be explained as the sum of the product {Σ kQ(AO-i) (S) [AO-i]/100} of the rate constant (kQ(AO-i) (S)) and the concentration ([AO-i]/100) of AO-i (Tocs, Toc-3s, and carotenoid) included.

Site-dependent Si KL23L23 resonant Auger electron spectra following inner-shell excitation of Cl3SiSi(CH3)3.

Spectator resonant Auger electron spectra with the Si 1s photoexcitation of Cl3SiSi(CH3)3 have been measured using an electron spectroscopic technique combined with undulator radiation. The transition with the highest intensity in the total ion yield (TIY) spectrum, coming from excitation of a Si 1s electron on the Cl-side into a vacant valence orbital, generates the resonant Auger decay in which the excited electron remains in this valence orbital. Photoexcitation of 1s electrons into some Rydberg orbitals induces Auger shake-down transitions, because higher-lying Rydberg orbitals in the two Si atoms closely positioned hold spatially overlapping considerably. A broad TIY peak slightly above the 1s ionization thresholds appreciably yields resonant Auger decays in which a slow photoelectron is re-captured into a higher-lying Rydberg orbital. The normal Auger peak shape at this photon energy is distorted due to a post-collision interaction effect. These findings provide a clear understanding on properties of the excited orbitals which are ambiguous in the measurement of the TIY only.

A study to control chemical reactions using Si:2p core ionization: site-specific fragmentation.

In an aim to create a "sharp" molecular knife, we have studied site-specific fragmentation caused by Si:2p core photoionization of bridged trihalosilyltrimethylsilyl molecules in the vapor phase. Highly site-specific bond dissociation has been found to occur around the core-ionized Si site in some of the molecules studied. The site specificity in fragmentation and the 2p binding energy difference between the two Si sites depend in similar ways on the intersite bridge and the electronegativities of the included halogen atoms. The present experimental and computational results show that for efficient "cutting" the following conditions for the two atomic sites to be separated by the knife should be satisfied. First, the sites should be located far from each other and connected by a chain of saturated bonds so that intersite electron migration can be reduced. Second, the chemical environments of the atomic sites should be as different as possible.

Estimation of the carrier frequencies and proportions of potential patients by detecting causative gene variants associated with autosomal recessive bone dysplasia using a whole-genome reference panel of Japanese individuals.

Bone dysplasias are a group of rare hereditary diseases, with up to 436 disease types. Perinatal diagnosis is clinically important for adequate personalized management and counseling. There are no reports focused on pathogenic variants of bone dysplasias in the general population. In this study, we focused on autosomal recessive bone dysplasias. We identified pathogenic variants using whole-genome reference panel data from 3552 Japanese individuals. For the first time, we were able to estimate the carrier frequencies and the proportions of potential patients. For autosomal recessive bone dysplasias, we detected 198 pathogenic variants of 54 causative genes. We estimated the variant carrier frequencies and the proportions of potential patients with variants associated with four clinically important bone dysplasias: osteogenesis imperfecta (OI), hypophosphatasia (HPP), asphyxiating thoracic dysplasia (ATD), and Ellis-van Creveld syndrome (EvC). The proportions of potential patients with OI, ATD, and EvC based on pathogenic variants classified as "pathogenic" and "likely pathogenic" by InterVar were closer to the reported incidence rates in Japanese subjects. Furthermore, the proportions of potential patients with HPP variants classified as "pathogenic" and "likely pathogenic" in InterVar and "pathogenic" in ClinVar were closer to the reported incidence rates. For bone dysplasia, the findings of this study will provide a better understanding of the variant types and frequencies in the Japanese general population, and should be useful for clinical diagnosis, genetic counseling, and personalized medicine.

Finding of Remarkable Synergistic Effect on the Aroxyl-Radical-Scavenging Rates (ks) under the Coexistence of Vitamin E Homologues (or Vegetable Oils) and Ubiquinol-10: Proposal of A New Mechanism to Explain An Increase of ks Value.

Measurements of aroxyl (ArO · )-radical-scavenging rate constants (ksAOH) of antioxidants (AOHs) (i.e., α-, ß-, γ-, δ-Tocopherol (TocH) and ubiquinol-10 (UQ10H2)) were performed in ethanol/chloroform/H2O (50/50/1, v/v) solution, using stopped-flow spectrophotometry. ksAOH values were measured not only for each AOH, but also for the mixtures of two AOHs (i.e., TocH and UQ10H2). ksTocH values for α-, ß-, γ-, δ-TocH increased 1.21, 1.28, 1.55, and 1.19 times, respectively, under the coexistence of constant concentrations of UQ10H2. Similar measurements were performed for eight vegetable oils 1 - 8, containing different concentrations of α-, ß-, γ-, δ-tocopherol (TocH) and -tocotrienol (Toc-3H). ksOil values of all eight vegetable oils 1 - 8 also increased 1.24 - 1.54 times under the coexistence of constant concentrations of UQ10H2. A new mechanism to explain the notable increase of ksAOH values under the coexistence of two kinds of phenolic AOHs was proposed. UV-vis absorption of α-, ß-, γ-Toc · radicals, produced by reaction of α-, ß-, γ-TocHs (or vegetable oils 1 - 8) with ArO · , disappeared under the coexistence of TocHs (or oils) and UQ10H2, suggesting that the prooxidant reaction resulting from the presence of Toc · radicals is suppressed in the presence of UQ10H2.

Kinetic Study of Singlet-Oxygen Quenching and Aroxyl-Radical Scavenging Activities of Vitamin E Homologs and Fatty Acids Present in Vegetable Oils.

Recently, singlet-oxygen (1O2) quenching and aroxyl-radical (ArO·) scavenging rates (kQ and kS, respectively) of eight vegetable oils were measured in the ethanol/chloroform/D2O solution. Furthermore, the kQ and kS values and concentrations of four tocopherols and four tocotrienols contained in the vegetable oils were measured. In this study, the concentrations of nine fatty acids (including stearic, oleic, linoleic, and linolenic acids) comprising the above-mentioned eight vegetable oils were determined by gas chromatography. The kQ and kS values for ethyl stearate, ethyl oleate, ethyl linoleate, methyl linolenate, and glyceryl trioleate in the ethanol/chloroform/D2O solution were measured by UV-vis spectrophotometry. Based on the results obtained for the above-mentioned fatty acid esters, the kQ and kS values were estimated for nine fatty acids. Furthermore, comparisons of kQ values observed for the vegetable oils with the sum of the product {∑kQAO-i [AO-i]} of the kQAO-i values obtained for each antioxidant-i (AO-i) and the concentrations ([AO-i]) of AO-i (i.e., four tocopherols (& four tocotrienols) and nine fatty acids) contained in vegetable oils were performed. Based on the results, a detailed comparison of the contributions of the tocopherols (and tocotrienols) and the fatty acids to the 1O2-quenching rate constants (kQ) was performed. This indicated that both the tocopherols (and tocotrienols) and the fatty acids contribute to the 1O2- quenching. A similar comparison was conducted for the ArO· -scavenging rate constants (kS). The results suggested that only the tocopherols (and tocotrienols) contained in the oils contributed to the ArO· -scavenging, with negligible contribution from the fatty acids.

Kinetic study of the aroxyl radical-scavenging reaction of alpha-tocopherol in methanol solution: notable effect of the alkali and alkaline earth metal salts on the reaction rates.

A kinetic study of the aroxyl (ArO*) radical-scavenging reaction of alpha-tocopherol (alpha-TocH) has been performed in the presence of six kinds of alkali and alkaline earth metal salts (LiI, LiClO(4), NaI, NaClO(4), KI, and Mg(ClO(4))(2)) in methanol solution, using stopped-flow spectrophotometry. The decay rate of the ArO* for the reaction of alpha-TocH with ArO* increased linearly with increasing concentration of metal salts. The second-order rate constants (k(s)) for the reaction of alpha-TocH with ArO* increased in the order of no metal salt < KI approximately NaClO(4) approximately NaI

Successful Management of the Fetal Severe Anemia Associated with Jra Alloimmunization by Intrauterine Transfusion of Jr(a+) Red Blood Cells.

OBJECTIVE: We present a case of fetal severe anemia associated with Jra alloimmunization, which was managed using Doppler measurement of the peak systolic velocity of the fetal middle cerebral artery (MCA-PSV) and intrauterine transfusion (IUT) of Jr(a+) red blood cells (RBCs). We also review the previous case reports on fetal or neonatal anemia associated with Jra alloimmunization. CASE REPORT: A woman with Jra alloimmunization was referred to our department at 29 weeks of gestation. As fetal MCA-PSV exceeded 1.55 multiples of the median, fetal blood sampling was performed and demonstrated severe anemia. During the course, a total of two IUTs were performed using Jr(a+) RBCs. The neonate was delivered by repeated cesarean section at 35 weeks of gestation and showed no apparent signs of hemolysis. CONCLUSION: Based on the literature review, fetal anemia associated with Jra alloimmunization becomes severe during mid-gestation and may not develop during late gestation. The severity of fetal anemia is predicted by MCA-PSV Doppler assessment rather than the maternal anti-Jra titers. Timely IUT of Jr(a+) RBCs can help to prolong the pregnancy to term in emergency situations wherein compatible blood of Jr(a-) RBCs is not available soon.

A Case of Monochorionic-Triamniotic Triplet Pregnancy with TRAP Sequence Successfully Treated with Radiofrequency Ablation with a Parallel Circuit Consisting of Anastomosed Blood Vessels between the Direct Pump Fetus and the Indirect Pump Fetus.

Monochorionic-triamniotic triplet pregnancy with twin reversed arterial perfusion (TRAP) sequence is one of the rare complications of multiple pregnancy and has been reported by only a few. Here, we report a case of monochorionic-triamniotic triplet pregnancy with TRAP sequence successfully treated with radiofrequency ablation, which did not develop polyhydramnios and heart failure although the estimated weight of the acardiac fetus increased twice as much as that of the direct pump fetus. Interestingly, the anastomosed blood vessels between the direct and indirect pump fetuses comprised a parallel circuit, which provided blood flow to the acardiac fetus. We hypothesized that the burden on the pump fetus in monochorionic pregnancy with TRAP sequence would be different between triplet and twin pregnancies.

Kinetic Study of the Quenching Reaction of Singlet Oxygen by Eight Vegetable Oils in Solution.

A kinetic study of the reaction of singlet oxygen (1O2) with eight vegetable oils 1-8 containing different concentrations of tocopherols (Tocs) and tocotrienols (Toc-3s) was performed. The second-order rate constants (kQ) for the reaction of 1O2 with vegetable oils 1-8 (rice bran, perilla, rape seed, safflower, grape seed, sesame, extra virgin olive, and olive oils) were measured in ethanol/chloroform/D2O (50:50:1, v/v/v) solution at 35°C using UV-vis spectrophotometry. Furthermore, comparisons of kQ values determined for the above oils 1-8 with the sum of the product {∑kQAO-i [AO-i]/105} of the kQAO-i values obtained for each antioxidant (AO-i) and concentration (in mg/100 g) ([AO-i]/105) of AO-i (Tocs and Toc-3s) contained in the oils 1-8 were performed. The observed kQ values were not reproduced by the kQ values calculated using only the concentrations of the four Tocs and Toc-3s. These results suggest that the contribution of fatty acids contained in the oils 1-8 is also necessary to fully explain the kQ values. Recently, the second-order rate constants (kS) for the reaction of aroxyl radical (ArO・) with the same vegetable oils 1-8 were measured in the same solvent at 25℃ using stopped-flow spectrophotometry (Ref. 23). The kS values obtained could be well explained as the sum of the product {Σ kSAO-i [AO-i]/105} of the kSAO-i and the [AO-i]/105 of AO-i (Tocs and Toc-3s) contained in the vegetable oils.

Exome-First Approach in Fetal Akinesia Reveals Chromosome 1p36 Deletion Syndrome.

BACKGROUND: Fetal akinesia refers to a broad spectrum of disorders with reduced or absent fetal movements. There is no established approach for prenatal diagnosis of the cause of fetal akinesia. Chromosome 1p36 deletion syndrome is the most common subtelomeric terminal deletion syndrome, recognized postnatally from typical craniofacial features. However, the influence of chromosome 1p36 deletion on fetal movements remains unknown. CASE REPORT: A 32-week-old fetus with akinesia showed multiple abnormalities, including fetal growth restriction, congenital cardiac defects, and ventriculomegaly. G-banding analysis using cultured amniocytes revealed 46,XY,22pstk+. Postnatal whole exome sequencing and subsequent chromosomal microarray identified a 3 Mb deletion of chromosomal region 1p36.33-p36.32. These results of molecular cytogenetic analyses were consistent with the fetal sonographic findings. CONCLUSION: Using the exome-first approach, we identified a case with fetal akinesia associated with chromosome 1p36 deletion. Chromosome 1p36 deletion syndrome may be considered for differential diagnosis in cases of fetal akinesia with multiple abnormalities.

Site-specific fragmentation caused by core-level photoionization in F(3)SiCH(2)CH(2)Si(CH(3))(3) vapor: comparison between Si:1s and 2p photoionizations by means of photoelectron-photoion-photoion triple-coincidence spectroscopy.

Site-specific fragmentation caused by Si:1s and 2p core-level photoionizations in F(3)SiCH(2)CH(2)Si(CH(3))(3) vapor was studied by energy-selected-photoelectron photoion-photoion triple-coincidence spectroscopy. The difference between the chemical shifts of the two Si sites is larger for the 1s ionization than for the 2p (2s) ionization. The fragmentation caused by the Si:1s ionization is more violent than that caused by the Si:2p ionization. The ions and ion pairs showing high site specificity for the Si:1s ionization belong to small fragments compared to those in the Si:2p ionization. Criteria for high site-specificity in fragmentation are discussed in conjunction with the present results.

Comparison between the free-radical-scavenging activities with vitamin E and ubiquinol in biological systems based on their reaction rates: a research account.

Detailed kinetic studies have been performed for the reaction of aroxyl (ArO.) radical with vitamin E (alpha-, beta-, gamma-, delta-tocopherol, TocH), ubiquinol-10, and related antioxidants in micellar solution, using a stopped-flow spectrophotometer. The second-order reaction rates (ks) obtained increased in the order of hydroquinone < tocol

Measurements of Singlet Oxygen-Quenching Activity of Vitamin E Homologs and Palm Oil and Soybean Extracts in a Micellar Solution.

Recently, a new assay method that can quantify the singlet oxygen-absorption capacity (SOAC) of antioxidants (AO) and food extracts in homogeneous organic solvents has been proposed. In the present study, second-order rate constants (kQ ) for the reaction of singlet oxygen (1 O2 ) with vitamin E homologs (α-, ß-, γ-, and δ-tocopherols [Toc] and α-, ß-, γ-, and δ-tocotrienols [Toc-3]) were measured in an aqueous Triton X-100 (5.0 wt%) micellar solution (pH 7.4). Toc-3 showed kQ values larger than those of Toc in a micellar solution, although Toc and Toc-3 showed the same kQ values in a homogeneous solution. Similar measurements were performed for 5 palm oil extracts 1-5 and one soybean extract 6, which contained different concentrations of Toc, Toc-3, and carotenoids. It has been clarified that the 1 O2 -quenching rates (kQ ) (that is, the relative SOAC value) obtained for extracts 3-6 may be explained as the sum of the product ΣkQAO-iAO-i/100 of the rate constant ( kQAO-i ) and the concentration ([AO-i]/100) of AO-i contained. The UV-vis absorption spectra of Toc and Toc-3 were measured in a micellar solution and chloroform. The results obtained demonstrated that the kQ values of AO in homogeneous and heterogeneous solutions vary notably depending on (1) polarity (dielectric constant [ε]) of the reaction field between 1 O2 and AO, (2) the local concentration of AO, and (3) the mobility of AO in solution. The results suggest that the SOAC method is applicable to the measurement of 1 O2 -quenching activity of general food extracts in a heterogeneous micellar solution.

Structure-activity relationship of the free-radical-scavenging reaction by vitamin E (alpha-, beta-, gamma-, delta-Tocopherols) and ubiquinol-10: pH dependence of the reaction rates.

The reaction rates (ks) of vitamin E (alpha-, beta-, gamma-, delta-tocopherols, TocH), ubiquinol-10, and related antioxidants (tocol, ubiquinol-0, and hydroquinone) with aroxyl (ArO(.-)) radical have been measured in micellar solution by stopped-flow spectrophotometer. The ks values increased in the order of hydroquinone < tocol < delta-TocH < ubiquinol-0 < gamma-TocH approximately beta-TocH < ubiquinol-10 < alpha-TocH at pH 4 approximately 8. The antioxidants which have lower oxidation potentials showed higher reactivities. The ks values of alpha-, beta-, gamma-, delta-tocopherol, and tocol remained constant between pH 4 and 10, and decreased rapidly at pH 11 approximately 12 by increasing pH value. From the pH dependence of ks values, the pKa values (= 13.1 approximately 12.6) have been determined for these tocopherols. The ks values of ubiquinol-10 also remained constant between pH 4 and 9, and increased rapidly at pH 9.5. Ubiquinol-10 is dibasic acid and can exist in three different molecular forms, depending on the pH value. By comparing the ks values with the mole fraction of each molecular form of ubiquinol-10, the reaction rate ks1 (= 1.21 x 10(5) M(-1)s(-1)) for the undissociated form, ks2 (= 1.04 x 10(6) M(-1)s(-1)) for monoanion and ks3 (= 0 M(-1)s(-1)) for dianion, and the pKa1 and pKa2 values (= 11.4 and 12.7) were determined. The ks2 value is 8.6 times as large as the ks1 value. Similar analyses were performed for ubiquinol-0 and hydroquinone. It was found that the relative ratio of ks values (100:21:20:2.9) of alpha-, beta-, gamma-, delta-tocopherols in micellar dispersion has good correlation with the relative biopotency ratios for rat fetal resorption, rat hemeolysis, and chicken muscle dystrophy. The relative antioxidant activities of alpha-tocopherol and ubiquinol-10 have been discussed based on the ks values obtained and their concentrations in serum and several tissues (heart, muscle, liver, kidney, and brain).