27 Vitrification at the germinal vesicle stage does not trigger apoptosis in porcine oocytes and early embryos

Porcine immature oocytes can survive vitrification at high rates and retain their ability to undergo maturation and fertilization; however, the procedure reduces their competence for subsequent embryo development via unknown mechanisms (Somfai et al. 2014 Plos One 9, e97731). The aim of the present study was to clarify whether our vitrification procedure at the germinal vesicle stage triggers apoptosis in oocytes and subsequent developing embryos. Immature porcine cumulus-oocyte complexes obtained from slaughterhouse-derived ovaries were vitrified and warmed by our method (Appeltant et al. 2018 Cryobiology 85, 87-94) immediately after collection (vitrified group). The oocytes were equilibrated in 2% (vol/vol) ethylene glycol and 2% (vol/vol) propylene glycol for 13-15min. Then, they were vitrified by dropping them into liquid nitrogen in 2-μL microdrops of a medium composed of 17.5% ethylene glycol, 17.5% propylene glycol, 0.3M sucrose, and 50mgmL−1 polyvinylpyrrolidone. After warming, they were subjected to IVM, fertilization (IVF), and embryo culture using chemically defined media (Yoshioka et al. 2008 J. Reprod. Dev. 54, 208-213). From each collected batch, a group of oocytes was processed without vitrification (control group). Apoptosis was assayed in membrane-intact oocytes at the end of IVM and in cleavage-stage embryos on Day 2 after IVF (Day 0) by the CaspACE FITC-VAD-FMK In Situ Caspase Marker (Promega; Experiment 1), deoxynucleotidyl transferase (TdT) dUTP nick-end labelling (TUNEL; Experiment 2), and analysis of mRNA levels by RT-qPCR for the pro-apoptotic Bax and CASP3 genes (Experiment 3). Each experiment was replicated three times. Data were analysed by Kruskal-Wallis test followed by Dunn's multiple comparisons test. The mean survival rate of vitrified oocytes was 89.2%. There was no significant difference between the control and vitrified groups in relative caspase levels in IVM oocytes and in 2- to 4-cell embryos after IVF; however, significantly increased caspase activity (P<0.05) was detected in oocytes and embryos after treatment with 10 μM staurosporine (positive control). There was no significant difference between the control and vitrified groups in the proportion of TUNEL-positive oocytes (4.1 and 0.8%, respectively) and embryos (0 and 0%, respectively), whereas 96.6% of oocytes and 100% of cleavage stage embryos treated with 1000IUmL−1 deoxyribonuclease I (positive control) were proven to be TUNEL positive (P<0.05). Similar mRNA levels for Bax and CASP3 genes were detected in oocytes at the end of IVM and subsequent developing 4- to 8-cell embryos between the control and vitrified groups. In conclusion, vitrification of porcine oocytes at the germinal vesicle stage by our method did not trigger apoptosis in oocytes and subsequent developing embryos. This work was supported by the Japan Science and Technology Agency (JST)/Japan International Cooperation Agency (JICA) Science and Technology Research Partnership for Sustainable Development (SATREPS).

2140Association of arterial stiffness with left atrial structure and phasic function: a community-based cohort study

Background

Increased arterial stiffness is recognized as an independent risk factor for atrial fibrillation, although the pathophysiological mechanisms remain unclear. Cardio-ankle vascular index (CAVI) is emerging as an important tool to assess arterial stiffness noninvasively which is derived from the concept of stiffness β index and is less dependent on blood pressure at the time of measurement than pulse wave velocity.

Purpose

This study aimed to investigate the association of arterial stiffness with left atrial (LA) volume and phasic function in a community-based cohort.

Methods

We included 1,156 participants without overt cardiovascular disease who underwent extensive cardiovascular examination. Arterial stiffness was evaluated by CAVI. Speckle-tracking echocardiography was employed to evaluate LA phasic function including reservoir, conduit and pump strain as well as left ventricular global longitudinal strain (LVGLS).

Results

CAVI was negatively correlated with reservoir and conduit strain (r=−0.37 and −0.45, both p<0.001; Figure), whereas weakly, but positively correlated with LA volume index and pump strain (r=0.12 and 0.09, both p<0.01). In multivariable analysis, CAVI was significantly associated with reservoir and conduit strain independent of traditional cardiovascular risk factors, pertinent laboratory parameters and LV morphology and function including LVGLS (standardized β=−0.22 and −0.26, respectively, both p<0.001), whereas there was no independent association with LA volume index and pump strain. In the categorical analysis, the abnormal CAVI (≥9.0) carried the significant risk of impaired reservoir (<31.4%) and conduit (<12.4%) strain (adjusted odds ratio = 2.63 and 3.71 vs. normal CAVI, both p<0.01) in a fully-adjusted model including laboratory and echocardiographic parameters.

Figure 1

Conclusion

Arterial stiffness was independently associated with LA reservoir and conduit function, even in the absence of overt cardiovascular disease. This association may explain the higher incidence of atrial fibrillation in individuals with increased arterial stiffness.

P5293Effect of metabolically health obesity on carotid intima-media thickness in general population: a community-based cohort study

Introduction

Obesity is a common and independent risk factor for all-cause mortality. More specifically, obesity is a major component of atherosclerosis in association with metabolic disorders including metabolic syndrome (MetS), resulting in various cardiovascular diseases (CVD). Alternatively, obese subjects without MetS are prevalent, also referred to as metabolically healthy obesity (MHO). However, most preceding studies regarding MHO have been limited by small cohorts. Therefore, the effect of MHO on atherosclerosis in the general population remains unclear.

Purpose

In this study, we sought to clarify the effect of MHO on carotid intima-media thickness (IMT) as a marker of early stage atherosclerosis using a community-based cohort in general population.

Methods

We examined subjects who underwent medical check-up at our University Hospital. We defined obesity as body mass index ≥25.0 kg/m2. Abdominal obesity, defined as waist circumstance at umbilical level ≥85 cm in men and ≥90 cm in women, was obligatory for the diagnosis of MetS. In addition to abdominal obesity, any two of the following three abnormalities should be observed for the diagnosis of MetS, [1] Dyslipidemia: triglyceride ≥150 mg/dL, HDL-C <40 mg/dL, or use of lipid lowering medication, [2] Hypertension: systolic blood pressure ≥130 mmHg, diastolic blood pressure ≥85 mmHg, or use of antihypertensive medication, and [3] Hyperglycemia: fasting plasma glucose ≥110 mg/dL or use of hypoglycemic medication. MHO was defined as obese subjects without MetS, whereas we defined metabolically unhealthy obesity (MUO) as obese subjects with MetS. We defined carotid plaque as IMT ≥1.1 mm.

Results

Among 1,241 subjects, 857 subjects (69%) were categorized in the normal body weight group, whereas 275 subjects (22%) were categorized as MHO, and 109 subjects (9%) were categorized as MUO. Compared to non-obese subjects, prevalence of classical cardiovascular risk factors including hypertension, diabetes mellitus, and dyslipidemia increased in subjects with MHO, and further increased in those with MUO. IMT was higher in obese subjects compared to those without obesity. Similarly, the prevalence of carotid plaque formation was also higher in obese subjects. Multivariable logistic regression analysis demonstrated that age ≥60 years, male sex, hypertension, diabetes mellitus, MHO subjects (Odds ratio [OR]; 1.6, p=0.005), and MUO subjects (OR 1.7, p=0.04) were independently associated with carotid plaque formation. There was no statistical difference in the risk of carotid plaque formation between subjects with MHO and MUO.

IMT and Carotid Plaque

Conclusions

IMT and the prevalence of carotid plaque are higher in both subjects with MHO and MUO compared to non-obese subjects in the general population. We need to take obesity regardless of the presence of MetS into consideration as high-risk subjects for subsequent CVD.

P4389Effect of cigarette smoking on carotid artery atherosclerosis: a community-based cohort study

Background

Cigarette smoking is closely associated with the development of cardiovascular diseases (CVD), and the European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines recommend smoking bans.On the other hand, the relationship between cigarette smoking and subclinical atherosclerosis has not been fully studied. Carotid intima-media thickness (cIMT) is commonly used as a subclinical atherosclerosis marker, and a carotid plaque feature is also known to be an important predictor of cardiovascular diseases.

Purpose

We sought to clarify the association between cigarette smoking and subclinical atherosclerosis by evaluating carotid plaque including cIMT and carotid plaque features in general population.

Methods and results

Among 1,209 participants with no prior coronary artery disease who received a medical check-up with cardiovascular examination at our institution, 450 participants (37.2%) were smokers (including both past and current smokers). We defined carotid plaque as cIMT ≥1.1 mm and high-risk plaque as carotid plaque with hypoechoic dominant and/or plaque ulceration. The value of cIMT and the rate of carotid plaque were not different between smokers and never smokers (Figure A & B). However, the rate of carotid high-risk plaque was significantly higher in participants with smokers than those with never smokers (29.7%, vs 23.5%, p=0.011) (Figure C). Even after adjustment with covariates including age, gender and traditional cardiovascular risk factors, cigarette smoking was independently associated with high-risk plaque formation (odds ratio 1.384, 95% CI 1.020–1.877; p=0.037). According to the subgroup analysis classified by age, cigarette smoking was associated with not only the development of high-risk plaque but also the increased value of cIMT in the subgroup over 60 years old, whereas only the rate of high-risk plaque was higher in smokers than never smokers in the subgroup under 60 years old.

Carotid plaque and smoking

Conclusion

The development of high-risk carotid artery plaque may precede thickening of cIMT in cigarette smokers, suggesting that the novel insight for the pathological mechanism underlying cardiovascular events and cigarette smoking.

Delayed lupus nephritis in the course of systemic lupus erythematosus is associated with a poorer treatment response: a multicentre, retrospective cohort study in Japan

Objective

The objective of this study was to investigate possible differences in treatment responses between two categories for the onset of lupus nephritis.

Methods

We performed a multicentre, retrospective cohort study of class III–V lupus nephritis patients diagnosed between 1997 and 2014. The renal responses to initial induction therapy were compared between patients who developed lupus nephritis within one year from diagnosis of systemic lupus erythematosus (early (E-) LN) and the remainder (delayed (D-) LN) using the Kaplan–Meier method. We determined the predictors of renal response as well as renal flares and long-term renal outcomes using multivariate Cox regression analyses.

Results

A total of 107 E-LN and 70 D-LN patients were followed up for a median of 10.2 years. Log-rank tests showed a lower cumulative incidence of complete response in D-LN compared with E-LN patients. Multivariate analysis identified D-LN (hazard ratio (HR) 0.48, 95% confidence interval (CI) 0.33–0.70), nephrotic syndrome at baseline, and a chronicity index greater than 2 as negative predictors of complete response. D-LN patients were more likely to experience renal flares. D-LN (HR 2.54, 95% CI 1.10–5.83) and decreased renal function were significant predictors of chronic kidney disease at baseline.

Conclusion

D-LN was a predictor of poorer treatment outcomes, in addition to renal histology and severity of nephritis at lupus nephritis onset.

36 The effects of E-64 on the developmental competence of porcine oocytes vitrified at the germinal vesicle stage

Previous studies reported the activation of the apoptotic cascade by vitrification in mature porcine oocytes (Vallorani et al. 2012 Anim. Reprod. Sci. 135, 68-74) and that the cathepsin B inhibitor E-64 improved developmental competence of bovine oocytes via an antiapoptotic effect (Balboula et al. 2013 Reproduction 146, 407-417). The present study was carried out to test whether E-64 affected the developmental competency of porcine oocytes vitrified at the germinal vesicle stage. Cumulus-enclosed porcine oocytes were vitrified in microdrops and warmed by our method (Somfai et al. 2015 J. Reprod. Dev. 61, 571-579). Then, the oocytes were subjected to in vitro maturation (IVM) for 46h in a chemically defined porcine oocyte medium supplemented with 10ng mL−1 of epidermal growth factor, 10IU mL−1 of eCG, and 10IU mL−1 of hCG and during the first 22h of IVM with 1mM dibutyryl cyclic adenosine monophosphate. Then, cumulus-oocyte complexes were fertilized in vitro and presumptive zygotes were cultured in 50-µL drops of porcine zygote medium-3 for 7 days in 6-well dishes covered by paraffin oil in an atmosphere of 5% CO2, 5% O2, and 90% N2 at 39°C. On Day 5 (Day 0=IVF), the porcine zygote medium-3 was supplemented with 10% (vol/vol) FCS. The effects of 1.0μM of E-64 supplementation during IVM of non-vitrified and vitrified cumulus-oocyte complexes were investigated in a 2×2 factorial design. Survival rates after IVM, cleavage rates on Day 2, blastocyst rates, and total cell numbers in blastocysts on Day 7 were compared among groups. The experiment was replicated 5 times. Results were analysed by ANOVA and Tukey’s multiple comparison test. The percentages of live oocytes were statistically similar when oocytes were matured in the absence or presence of E-64 both in non-vitrified (99.2% v. 99.6%, respectively) and vitrified (94.3% v. 90.8%, respectively) groups. Similarly, IVM without or with E-64 supplementation had no effect on subsequent cleavage and blastocyst development rates in non-vitrified (67.4% v. 71.2% and 38.7% v. 43.2%, respectively) and vitrified (46.8% v. 48.8% and 14.6% v. 22.8%, respectively) oocytes. Irrespective of E-64 treatment, all survival and developmental rates in the vitrified groups were significantly lower (P&lt;0.05) compared with those of their non-vitrified counterparts except for the blastocyst development rate in the E-64-treated vitrified group, which did not differ significantly from those of the non-vitrified groups with or without E-64 treatment. There was no statistical difference in mean blastocyst cell numbers among the groups, ranging between 86.5±15.8 and 118±10.6. In conclusion, E-64 treatment had no effect on embryo production rates, which suggests that in our system, cathepsin-mediated apoptosis during IVM might not be the factor to limit embryo production using either fresh oocytes or those vitrified at the immature stage. This work was supported by JST/JICA SATREPS.

Autoantibodies to killer cell immunoglobulin-like receptor 3DL1 in patients with systemic lupus erythematosus

A genetic variant of the killer immunoglobulin-like receptor 3DL1 (KIR3DL1) has been found in patients with systemic lupus erythematosus (SLE). Herein, we investigated the presence of autoantibodies to KIR3DL1 in a cohort of patients with SLE. We tested sera from 28 patients with SLE, 11 patients with rheumatoid arthritis (RA) and 17 healthy control subjects for anti-KIR3DL1 activity by an enzyme-linked immunosorbent assay (ELISA) using recombinant KIR3DL1-enhanced green fluorescent protein (EGFP) and EGFP proteins. Anti-KIR3DL1 antibodies were detected in 22 (79%) of the 28 patients with SLE, whereas they were present in only three (27%) of the 11 patients with RA examined. Notably, 10 (91%) of the 11 samples from patients with SLE prior to therapy had anti-KIR3DL1 antibodies. None of the samples from healthy donors were positive for the antibodies. Here, we report the presence of anti-KIR3DL1 antibodies in the sera of patients with SLE for the first time. Anti-KIR3DL1 autoantibodies may be involved in the pathogenesis of autoimmune diseases.

Glucagonoma With Necrolytic Migratory Erythema: Metabolic Profile and Detection of Biallelic Inactivation of DAXX Gene

CONTEXT

Necrolytic migratory erythema (NME) occurs in approximately 70% of patients with glucagonoma syndrome. Excessive stimulation of metabolic pathways by hyperglucagonemia, which leads to hypoaminoacidemia, contributes to NME pathogenesis. However, the molecular pathogenesis of glucagonoma and relationships between metabolic abnormalities and clinical symptoms remain unclear.

PATIENT

A 53-year-old woman was referred to our hospital with a generalized rash and weight loss. NME was diagnosed by histopathological examination of skin biopsy tissue. Laboratory tests revealed diabetes, hyperglucagonemia, marked insulin resistance, severe hypoaminoacidemia, ketosis, and anemia. Enhanced computed tomography scans detected a 29-mm pancreatic hypervascular tumor, which was eventually diagnosed as glucagonoma. Preoperative treatment with octreotide long-acting release reduced the glucagon level, improved the amino acid profile, and produced NME remission. Surgical tumor excision normalized the metabolic status and led to remission of symptoms, including NME.

INTERVENTIONS

Whole-exome sequencing (WES) and subsequent targeted capture sequencing, followed by Sanger sequencing and pyrosequencing, identified biallelic alteration of death-domain associated protein (DAXX) with a combination of loss of heterozygosity and frameshift mutations (c.553_554del:p.R185fs and c.1884dupC:p.C629fs) in the glucagonoma. Consistently, immunohistochemistry confirmed near-absence of DAXX staining in the tumor cells. Tumor expression of glucagon and somatostatin receptor subtype 2 and 3 messenger RNA was markedly upregulated.

CONCLUSIONS

This is a report of glucagonoma with biallelic inactivation of DAXX determined by WES. The tumor manifested as glucagonoma syndrome with generalized NME. This case showed the relationship between hypoaminoacidemia and NME status. Further investigations are required to elucidate the underlying mechanisms of NME onset and glucagonoma tumorigenesis.

Lactate increases myotube diameter via activation of MEK/ERK pathway in C2C12 cells

AIM

Lactate is produced in and released from skeletal muscle cells. Lactate receptor, G-protein-coupled receptor 81 (GPR81), is expressed in skeletal muscle cells. However, a physiological role of extracellular lactate on skeletal muscle is not fully clarified. The purpose of this study was to investigate extracellular lactate-associated morphological changes and intracellular signals in C2C12 skeletal muscle cells.

METHODS

Mouse myoblast C2C12 cells were differentiated for 5 days to form myotubes. Sodium lactate (lactate) or GPR81 agonist, 3,5-dihydroxybenzoic acid (3,5-DHBA), was administered to the differentiation medium.

RESULTS

Lactate administration increased the diameter of C2C12 myotubes in a dose-dependent manner. Administration of 3,5-DHBA also increased myotube diameter. Not only lactate but also 3,5-DHBA upregulated the phosphorylation level of mitogen-activated protein kinase kinase 1/2 (MEK1/2), p42/44 extracellular signal-regulated kinase-1/2 (ERK1/2) and p90 ribosomal S6 kinase (p90RSK). MEK inhibitor U0126 depressed the phosphorylation of ERK-p90RSK and increase in myotube diameter induced by lactate. On the other hand, both lactate and 3,5-DHBA failed to induce significant responses in the phosphorylation level of Akt, mammalian target of rapamycin, p70 S6 kinase and protein degradation-related signals.

CONCLUSION

These observations suggest that lactate-associated increase in the diameter of C2C12 myotubes is induced via activation of GRP81-mediated MEK/ERK pathway. Extracellular lactate might have a positive effect on skeletal muscle size.

Efficient Signal Processing of Multineuronal Activities for Neural Interface and Prosthesis

Objectives : Multineuronal spike trains must be efficiently decoded in order to utilize them for controlling artificial limbs and organs. Here we evaluated the efficiency of pooling (averaging) and combining (vectorizing) activities of multiple neurons for decoding neuronal information.

Methods : Multineuronal activities in the monkey inferior temporal (IT) cortex were obtained by classifying spikes of constituent neurons from multichannel data recorded with a multisite microelectrode. We compared pooling and combining procedures for the amount of visual information transferred by neurons, and for the success rate of stimulus estimation based on neuronal activities in each trial.

Results : Both pooling and combining activities of multiple neurons increased the amount of information and the success rate with the number of neurons. However, the degree of improvement obtained by increasing the number of neurons was higher when combining activities as opposed to pooling them.

Conclusion: Combining the activities of multiple neurons is more efficient than pooling them for obtaining a precise interpretation of neuronal signals.

Case of lipoatrophic diabetes induced by juvenile dermatomyositis

Lipodystrophy is a rare condition that is often accompanied by one or more metabolic diseases. Here, we report a case of lipoatrophic diabetes induced by juvenile dermatomyositis. Although pioglitazone was not effective for lowering blood glucose levels, our observation suggested that it improved liver function slightly. The effectiveness of metreleptin for lowering blood glucose levels could not be determined, as we administered it in a short period. Liver biopsy showed burned-out non-alcoholic steatohepatitis. The present results show that the successful treatment of lipoatrophic diabetes induced by juvenile dermatomyositis requires an early diagnosis and therapeutic intervention.

39 THE EFFECTS OF RESVERATROL DURING IN VITRO MATURATION ON THE DEVELOPMENTAL COMPETENCE OF PORCINE OOCYTES VITRIFIED AT THE IMMATURE STAGE

Previously, live offspring have been produced from porcine oocytes vitrified at the immature stage (Somfai et al. 2014 PLoS One 9, e97731); however, their embryo developmental rates remain low. The aim of our current research was to test the effects of resveratrol, an antioxidant and anti-apoptotic agent on the developmental competence of immature vitrified oocytes during in vitro maturation (IVM) after warming. Follicular porcine cumulus-oocyte complexes (COC) were vitrified on Cryotop® sheets (Kitazato Corp. Shizuoka, Japan) using the cryoprotectant treatment and warming method of Somfai et al. (2015 J. Reprod. Dev. 61, 571–579). After warming, the oocytes were subjected to IVM for 46 h in a chemically defined porcine oocyte medium (POM) enriched with 10 ng mL−1 epidermal growth factor, 10 IU mL−1 eCG, and 10 IU mL−1 hCG. During the first 22 h of IVM, the medium was supplemented with 1 mM dibutyryl cAMP. The following 24 h of IVM was performed in POM without dibutyryl cAMP. Vitrified/warmed COC (vitrified group) and freshly collected COC (control group) were matured either in the absence or presence of 2 µM resveratrol (RES− and RES+, respectively) throughout the entire IVM. At the end of IVM, oocytes were denuded and their survival was evaluated. Then, those with 1 polar body (PB1+) were selected for parthenogenetic activation (Day 0). Activated oocytes were cultured for 7 days in PZM-3. Survival, nuclear maturation, cleavage, and blastocyst rates were assessed. The experiment was replicated 5 times. Results were analysed by one-way ANOVA and Tukey’s multiple comparison test. Vitrification reduced the percentage of live oocytes after IVM both in RES− and RES+ groups in a similar manner (47.9 and 51.8%, respectively) compared with control RES− and RES+ groups (99.4 and 100%, respectively; P < 0.05) There was no statistical difference among groups in the percentage of PB1+ oocytes (ranging between 76.1 and 90.2%). On Day 2, the cleavage rate in vitrified RES− group was lower than those in control RES− and RES+ groups (55.9 v. 78.5% and 79.2%, respectively) whereas the vitrified RES+ group did not differ from the others (72.1%). The blastocyst developmental rate calculated from total cultured oocytes on Day 7 in vitrified RES+ group was significantly higher (P < 0.05) than that in the vitrified RES− group (26.2% v. 6.9%, respectively) and did not differ significantly from those of control RES− and RES+ groups (32.1 and 36.0%, respectively). Blastocyst rates in control RES− and RES+ groups were significantly higher (P < 0.05) than that in vitrified RES− group but did not differ from one another. In conclusion, supplementation of IVM medium with resveratrol improved the developmental competence of vitrified, but not freshly collected oocytes. This work was supported by JSPS KAKENHI (Grant Number: 26870839) and JST/JICA SATREPS. E.C.S. Santos was supported by a CNPq-Brasil fellowship.

Comparison of indocyanine green angiography and optical coherence tomographic angiography in polypoidal choroidal vasculopathy

PurposeTo compare optical coherence tomographic angiography (OCTA) and indocyanine green angiography (ICGA) images for detecting polypoidal lesions (PLs) and branching vascular networks (BVNs), and to measure the polypoidal areas (PAs) in patients with polypoidal choroidal vasculopathy (PCV).MethodsAll patients underwent ICGA, optical coherence tomography (OCT), and OCTA. We compared the detection sensitivity for PL and BVN, as evaluated by the ICGA and OCTA images. Furthermore, PA measured by ICGA was divided into two groups: one in which the area could be measured by OCTA (ICGA+OCTA+) and the other in which the area could not be measured by OCTA (ICGA+OCTA-).ResultsTwenty-one consecutive eyes of 21 patients (mean age, 73.8±9.8 years) were included. ICGA detected PL in all eyes (100%), whereas OCTA detected PL in 16 eyes (75.2%); ICGA detected BVN in 15 eyes (71.4%), whereas OCTA detected BVN in 20 eyes (95.2%). The mean PA in ICGA+OCTA+ and ICGA+OCTA- was 0.24±0.04 and 0.14±0.01 mm2, respectively; a significant difference was observed between ICGA+OCTA+ PA and ICGA+OCTA- PA (P<0.0001). In addition, the mean PA in the ICGA+OCTA+ group measured by ICGA and OCTA was 0.24±0.04 was 0.19±0.04 mm2, respectively; these values were significantly different (P=0.0046).ConclusionsOCTA might detect more BVNs and fewer PLs compared with ICGA, and PL detected by OCTA might be smaller than those detected by ICGA.

Application of silica gel-sintered plate to thin layer lipid chromatographic analysis

The merits and disadvantages of using the silica gel-sintered plate for lipid chromatographic analysis were investigated in detail. The commercially available sintered plate could be used repeatedly, employing the reconditioning procedure which involved chromic-sulfuric acid treatment and subsequent activation. The reconditioned sintered plate has now been used successfully 20 times, for lipid analysis without any deterioration of the excellent resolution power for complex lipid mixtures for all the solvent systems. Since the sintered plate is sturdy, the chromatogplate could be immersed directly in the liquid reaction mixture, so that spots on the chromatogram could be seen and impregnated plates prepared simply. The sintered plate was found to be much more economical than the silica gel-coated plate.