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Jing Lin

Publications and source records attributed to Jing Lin.

At least 55 records · Page 3Linked to original sources

Macrocyclic bisbinaphthyl fluorophores and their acyclic analogues: signal amplification and chiral recognition.

A series of optically active macrocyclic and acyclic bisbinaphthyls have been synthesized and characterized. The structure of one of the bisbinaphthyl macrocycles has been established by a single-crystal X-ray analysis. The UV and fluorescence spectra of these chiral compounds in various solvents and at different concentrations are studied. Formation of excimers is observed for the macrocyclic bisbinaphthyl compounds. Introduction of conjugated substituents to the 6,6'-positions of the binaphthyl units in the macrocycles leads to greatly amplified fluorescence signals. Using the 6,6'-substituted bisbinaphthyl macrocycles in place of the unsubstituted macrocycles allows a 2 orders of magnitude reduction in the sensor concentration for the fluorescence measurements. These macrocycles have exhibited highly enantioselective fluorescent enhancements in the presence of chiral alpha-hydroxycarboxylic acids and N-protected alpha-amino acids. They are useful as fluorescent sensors for chiral recognition. The macrocycles show much greater enantioselectivity in the substrate recognition than their acyclic analogues.

Fluorescent Dyes↗

Inhibiting S100B restores p53 levels in primary malignant melanoma cancer cells.

S100 calcium-binding proteins such as S100B are elevated in primary malignant melanoma and are used as markers for this and numerous other cancers. Wild-type p53 protein levels are relatively low in these cancer cells (i.e. when compared with cells without S100B) but are elevated when RNA antisense to S100B is introduced. This result implicates S100B in the down-regulation of p53 and is consistent with the large decreases in p53 protein levels observed previously in transient co-transfections of p53 and S100B (Lin, J., Blake, M., Tang, C., Zimmer, D., Rustandi, R. R., Weber, D. J., and Carrier, F. (2001) J. Biol. Chem. 276, 35037-35041). Down-regulation of p53 in primary malignant melanoma cells is likely the result of a direct interaction with S100B, which was observed by co-immunoprecipitation experiments. Furthermore, p53 binds regions of the S100B promoter, one of which matches the 20-nucleotide p53-binding consensus DNA sequence perfectly. Therefore, when p53 levels increase, it contributes to its own demise by up-regulating the transcription of S100B as part of a negative feedback loop. This is analogous to what is found for another protein that down-regulates p53, namely hdm2 (human double mutant 2).

Binding Sites↗

The expression and processing of two recombinant 2S albumins from soybean (Glycine max) in the yeast Pichia pastoris.

Soybean seeds contain two 2S albumin storage proteins (AL1 and AL3) which may contribute to their industrial processing quality and allergenicity. We show that these proteins (AL1 and AL3) are well expressed by the methylotrophic yeast Pichia pastoris and that one of the secreted proteins (AL3) has a similar conformation and stability to that purified from soybean seeds. Further, we show that the subunits are post-translationally processed within the same loop region as the native protein but with some differences in the precise sites. This internal processing provides useful information on the endoproteolytic activity in P. pastoris. We also show that, similar to many plant allergens, the 2S albumins from soybean are stable to heat and chemical treatments.

2S Albumins, Plant↗

Extraction and purification of biologically active intestinal trefoil factor from human meconium.

Intestinal trefoil factor (TFF3/ITF), a member of trefoil factor family (TFF) domain peptides, is normally expressed by goblet cells and secreted into the lumen of the intestinal tract, and plays an important role in the maintenance and repair of the intestinal mucosal barrier. Significant amounts of TFF3/ITF are present in the meconium of human infants. Here, we describe a relatively simple method for extraction and purification of natural human TFF3/ITF from meconium. The purification methods include acid treatment, ammonium sulfate precipitation, isoelectric precipitation, and iron exchange chromatography. A relatively large amount of natural TFF3/ITF can be purified from meconium of full-term infants and this purified, natural TFF3/ITF is biologically active in an ethanol-induced rat gastric mucosal injury model.

Animals↗

Effect of total parenteral nutrition and choline on hepatic flavin-containing and cytochrome P-450 monooxygenase activity in rats.

Total parenteral nutrition provides nutrition by infusion into the systemic circulation. Bypassing the intestine and processes associated with absorption can cause additional pathophysiological changes to occur. For example, in rats, normal gut and pancreatic cell function may change, absorptive capacity may be altered, and enzyme functional activity including drug metabolism may be affected. The objective of this study was to examine the effects of a control diet or a diet of total parenteral nutrition in the presence or absence of choline on urinary biomarkers and hepatic microsome functional activity from rats. Selective functional markers of cytochrome P-4502E1 (CYP2E1) and flavin-containing monooxygenase (FMO) were examined in vitro. The N-oxygenation of trimethylamine was used as an in vivo selective functional marker for FMO. After the administration of total parenteral nutrition plus choline for 5 days, the urinary excretion of trimethylamine and trimethylamine N-oxide declined approximately 7- and 3-fold, respectively, compared with rats treated with control diet. The concentration of urinary biogenic amines was also significantly affected by total parenteral nutrition. Compared with control animals, rats administered total parenteral nutrition plus choline for 5 days showed a decrease of approximately 5- and 2-fold in urinary dopamine and norepinephrine concentration, respectively. To examine a molecular basis for the influence of total parenteral nutrition +/- choline on monooxygenase regulation, hepatic microsomal activity of the FMO and CYP2E1 was examined. Compared with animals treated with a control diet, total parenteral nutrition plus choline in rats caused a 3-fold increase in hepatic microsomal FMO and a 2-fold increase in hepatic cytochrome CYP2E1 functional activity, respectively. Although the data did not reach statistical significance, selective immunoblot studies using hepatic microsomes from rats treated with total parenteral nutrition + choline showed that compared with controls, FMO1 protein was decreased 1.4-fold and FMO3 increased 1.3-fold, respectively. In hepatic microsomes from rats treated with total parenteral nutrition + choline, compared with control animals, FMO4 immunoreactivity was increased 1.6-fold. The data suggest that total parenteral nutrition has a detectable effect on modulating rat FMO3, FMO4, and CYP2E1 monooxygenase functional activity. The clinical relevance of these results is unknown but may be of significance for individuals receiving total parenteral nutrition and those afflicted with trimethylaminuria.

Animals↗

Myocardial protection of warm cardioplegic induction on the isolated perfused rat heart model.

Myocardial protection through different cardioplegia approaches is an important issue for successful cardiovascular surgery. The objective of this prospective randomized study was to evaluate the effect of myocardial protection of warm (37 degrees C) and cold (6 degrees C) cardioplegic induction, respectively, using a Langendorff isolated rat heart perfusion model. Twenty-eight isolated rat hearts on the Langendorff perfusion model were randomly divided into two groups: group T (n = 14) received warm (37 degrees C) cardioplegic induction, followed by cold (6 degrees C) cardioplegia after ECG showed straight line; alternatively, group C (n = 14) received only cold cardioplegic induction. After undergoing ischemia for 80 min, both group T and group C received reperfusion with Krebs-Henseleit Buffer (KHB) for 40 min. An additional group A (n = 7) received KHB continuously for 120 min and served as the control group for the assessment of Na(+)/K(+)-ATPase activity. The coronary flow, concentration of creatine kinase (CK) in coronary effluent, and cardiac function were evaluated at different time periods. Na(+)/K(+)-ATPase activity was assessed at the end of reperfusion. The coronary flow, content of CK in coronary effluent, heart rate, dp/dtmax, and left ventricular peak pressure (LVPP) were significantly greater (p < .05) in group T than group C during the reperfusion period. The negative value of -dp/dtmax and left ventricular end-diastolic pressure (LVEDP) was significantly lower (p < .05) in group T than group C, during the reperfusion period. The Na(+)/K(+)-ATPase activity assessed at the end of reperfusion period was significantly higher (p < .05) in group A and group T than group C, while no significant difference (p = .13) was found between group T and group A. Compared with cold cardioplegic induction, warm cardioplegic induction provides superior myocardial protection by enhancing coronary flow, reducing myocardial injury, improving cardiac function, and preserving Na(+)/K(+)-ATPase activity.

Animals↗

[Association between a genomic polymorphism within the CD14 locus and severe sepsis susceptibility as well as prognosis in patients after extensive burns].

OBJECTIVE: To investigate the relation of a lipopolysaccharide receptor CD14C-159T gene polymorphism to severe sepsis susceptibility and prognosis in patients with extensive burns. METHODS: The study group consisted of 118 normal controls and 16 patients with burns covering more than 60 percent total body surface area. Typing of each patient for the CD14C-159T gene polymorphism was performed by analyzing restriction fragments of a Hae III-digested DNA fragment obtained using polymerase chain reaction (PCR-RFLP). Genotypes were then related to the susceptibility and mortality rate of severe sepsis. RESULTS: The overall allele frequency (C 43.7 percent, T 56.3 percent) and genotype distribution (C homozygous 12.5 percent, C/T 62.5 percent, T homozygous 25.0 percent) were in agreement with the distribution in healthy volunteers. Genotype distribution in patients with severe sepsis was different from that in patients with an uncomplicated clinical course. Development of severe sepsis was increased in patients homozygous for the allele T (71.4 percent) than that of the non- sepsis patients (44.4 percent). CONCLUSION: The single base pair polymorphism at position-159 in the CD14 gene promoter might influence the development of severe sepsis in patients with extensive burns.

Adult↗

[Interaction of p53 with p53 response element like binding sequence at upstream of hepatitis B virus enhancer I].

BACKGROUND & OBJECTIVE: A p53 response element like binding sequence, 5'-TGCC(G)T-TGCCT-3' was found at upstream of hepatitis B virus (HBV) enhancer I from 1047 to 1059 nucleotides after analyzing the HBV genome by a computer program in our previous work. It indicated that the sequence could specifically bind P53 protein in vitro by electrophoretic mobility shift assay (EMSA) and electrophoretic mobility supershift assay (EMSSA). This study was designed to further investigate the interaction between P53 and p53 response element like binding sequence at upstream of HBV enhancer I. METHODS: HBV x gene enhancer and promoter which contains p53 response element like binding sequence TGCGT-TGCCT was in upstream of CAT enzyme in pX-CAT reporter plasmid. Firstly, we designed a point mutation in pX-CAT which change TGCGT TGCCT into TGTAT. TGTAT by polymerase chain reaction (PCR) in order to damage the p53 response element like sequence. After pX-CAT or mutation pX-CAT (mpX-CAT) transfected alone or cotransfected with pCMVp53 into HepG2 hepatoma cell, CAT activity was assayed to confirm the correlation of p53 protein with this DNA sequence. In addition, an antisense sequence corresponding to the p53 response element like sequence in HBV was reconstructed into the pZeoSV2 vector (alpha pZeoXP) and transfected into HepG2.2.15 cell line to block the binding of P53 with this sequence, the stable transfected HepG2.2.15 cell was observed about P53/P21 expression, cell cycle distribution and apoptosis rates. RESULTS: CAT enzyme of HepG2 had an higher expression in cotransfection with pCMVp53 and pX-CAT than alone pX-CAT (1.353 VS 0.738,P< 0.05), but it was lower in mpX-CAT(0.304) and pCMVp53 (0.402). Compared with the control group, P53/P21 expression and cell apoptosis rate decreased greatly in the stable transfected alpha pZeoXP HepG2.2.15 cell line (0.95% VS 7.84%), the cell number in S phase increased in the same cell line (16.37% VS 9.48%). CONCLUSION: Reporter gene expression of pX-CAT in intracellular could be promoted by P53, which further suggest that P53 could bind TGCC(G)T-TGCCT in upstream of HBV enhancer I and induce a prolonged P53 half life. Subsequently, P53 and p21 protein (downstream gene of P53) would have a higher expression and stronger activity.

Apoptosis↗

[Effects of hepatitis B virus X gene on p21(WAF1) expression through p53-dependent and p53-independent pathways].

BACKGROUND & OBJECTIVE: It was reported that the hepatitis B virus X could inhibit the function of p53 and have contrary effects on p21(WAF1), a downstream gene of p53, but the mechanism is not clear up to now. So this study was designed to investigate HBx's effect on p21(WAF1) gene. METHODS: After co-transfection of sense or antisense wild type p53 gene (wtp53) with HBx into SMMC-7721 and HBx alone transfection into other hepatoma cell lines with different endogenous status of p53, we evaluated the luciferase expression level under the p21(WAF1) promoter by detecting the luciferase activity and alteration of cell cycle in these transfected cell lines by flow cytometry. Expressions of p53 and p21 (WAF1) in hepatoma cells after transfected with HBx were also estimated by Western blot analysis. RESULTS: The luciferase activity (1.007+/-0.098) in SMMC-7721 cells cotransfected with HBx and sense-wtp53 was higher than that in cells with wtp53 gene alone (0.490+/-0.012, P< 0.05), and also was depressed in the other experimental groups transfected with HBx (P< 0.05). Western blot analysis showed that after transfected with HBx, p53 expression was elevated in all hepatoma cell lines with different endogenous status of p53, and the expression of p21(WAF1) and luciferase activity under the p21(WAF1) promoter (0.053+/-0.010 vs. 0.094+/-0.013, P< 0.05) were both decreased in SMMC-7721 cells with low expression of p53, but relatively increased in HepG2 cell line with high expression of p53 (1.252+/-0.052 vs. 0.767+/-0.031, P< 0.05). Flow cytometry showed that fewer SMMC-7721 (42.31%) and Hep3B (36.96%) cells were arrested in G(0)/G(1) phase in transiently transfected HBx groups than in the control groups (47.10% and 42.90%), which was the opposite case in HepG2 cell line (63.62% vs. 57.42%). Moreover, after stably transfected with pcDNA3HBx, HepG2 cells reduced in G(0)/G(1) phase in compared with the control group (57.31% vs 61.49%). CONCLUSION: HBx may not only increase the expression of p21(WAF1) by introducing the accumulation of p53 in cytoplasm but also inhibit the transcriptional activity of p21(WAF1) promoter in a p53-independent manner.

Carcinoma, Hepatocellular↗

[Interaction effect of p53 with HBV in hepatoma cell line SMMC-7721].

OBJECTIVES: To study the interaction of hepatitis virus B (HBV) and tumor suppressor p53. METHODS: Plasmid pCMVp53 was transfected or cotransfected with pCMVHBVa (wild type HBV) or PCMVHBVb (mutant type HBV) into the hepatoma cell line SMMC-7721 by lipofectamine. Apoptosis cells were labeled by annexin V-FITC and confirmed by flow cytometry. Reporter plasmids PG13-CAT or p21-luc were cotransfected respectively in each group to indicate transactivation activity of p53 and it's effect on p21 promoter. Western blot was performed to observe p53 expression in each group. RESULTS: The group transfected by pCMVp53 alone exhibit higher luciferase activity and higher apoptosis rate, otherwise, p53 expression, enzyme activity of PG13-CAT or p21- luc and cell apoptosis rate were much higher in the group cotransfected by pCMVp53 and pCMVHBVa, but not in the other cotransfected group; HBV replication was enhanced in p53 cotransfected group. CONCLUSION: p53 expression and effects could be enhanced by HBV and p53 had positive regulation effect on HBV replication.

Apoptosis↗

[Study of cooperation of tumor suppressor p33(ING1b) with p53 gene in hepatocellular carcinoma].

OBJECTIVE: To investigate the cooperation effect of p33(ING1b), coded protein of the novel tumor-suppressor gene ING1b, with p53 gene on the cell growth, cell cycle arrest, apoptosis and expression of the p53 downstream gene p21(WAF1/CIP1) in hepatocellular carcinoma. METHODS: Recombinant plasmids pcDNA3-INGIb containing sense p33(ING1b) cDNA, and pCMV-wtp53 containing sense p53 gene, and were transfected into HepG2, PLC/PRF/5 and Hep3B hepatoma cell lines with different p53 endogenous expression status using lipofecTAMINE method. Recombinant plasmids pcDNA3-alphaING1b containing antisense p33(ING1b) cDNA, pCMV-alphawtp53 containing antisense p53 gene, and plain vector as control were transfected into the cells. Forty-eight hours after transfection, the apoptosis rates were detected and cell cycle arrest were analyzed by flow cytometry. The expression of p33(ING1b) and wtp53 proteins were detected by Western blot. The luciferase gene reporter plasmid drived by p21(WAF1/CIP1) promoter was also transfected into the cells to analyze the activation of p21(WAF1/CIP1) gene in hepatoma cells. Then 6% ethanol was added into the in DMEM culture medium and all of the above experiments were repeated. RESULTS: After the p33(ING1b) gene was transfected, the apoptosis rate of HepG2 cells which express endogenous wtp53 was enhanced (22.53%), the number of cells arrested in G(0)/G(1) phase was increased (67.45%), and the activation of p21(WAF1/CIP1) promoter reached the highest level (13.08) (all P < 0.01). In the PLC/PRF/5 cells which express endogenous mutant p53, after combined p33(ING1b) and wtp53 gene transfection the percentage of cells arrested in G(0)/G(1) phase (78.16%) and the activation of p21(WAF1/CIP1) promoter (12.99) were higher than those in the experiment groups transfected with p33(ING1b) or wtp53 gene alone (both P < 0.01), however, the difference in apoptosis rate was not statistically significant (P > 0.05). After 6% ethanol treatment, apoptosis rate of PLC/PRF/5 cells transfected with combined p33(ING1b) and wtp53 gene was increased significantly (42.8%). The apoptosis rate and cell cycle arrest were not significantly different between the Hep3B cells with deletion of wtp53 which were transfected with p33(ING1b) and wtp53 gene and those of the control group (P > 0.05), however, the activity of the p21(WAF1/CIP1) promoter was activated in the combined transfectlion group (10.32, P < 0.01). CONCLUSION: p33(ING1b) cooperate with wtp53 in the process of inhibiting hepatoma cell growth, inducing apoptosis, and activating p53 downstream gene p21(WAF1/CIP1), and after chemical inducing reagent treatment the cooperation between p33(ING1b) and wtp53 gene is enhanced.

Apoptosis↗

Ontogeny and prenatal expression of trefoil factor 3/ITF in the human intestine.

BACKGROUND: Trefoil factor 3 (TFF3) or intestinal trefoil factor (ITF), a peptide normally expressed and secreted by goblet cells at the mucosal surface of the small intestine and colon, is important for the maintenance and repair of the intestinal mucosal barrier. AIM: To study the ontogeny and developmental expression of TFF3 in human intestine. SUBJECTS: We examined TFF3 expression in formalin-fixed and paraffin-embedded intestinal tissues from 24 fetuses (gestational age [GA] 12-23 weeks) and 5 adults by immunohistochemical staining. To determine whether TFF3 is excreted into the fetal intestinal tract, first-passed meconium samples were collected from 43 newborn infants (gestational age 24-41 weeks). The presence of TFF3 was examined by Western blot analysis and the relative levels of TFF3 in the meconium were quantified with a slot blot assay. RESULTS: TFF3 can be detected by immunohistochemistry in human intestine as early as 12 weeks gestation. TFF3 is present in the meconium of newborn infants; no significant difference exists in TFF3 levels in the meconium of premature infants with birth weight (BW) less than 1500 g compared to those with birth weight equal to or more than 1500 g. CONCLUSION: Premature infant's susceptibility to intestinal mucosal injury is unlikely to be explained by developmental expression of TFF3 in human intestine since secreted TFF3 is not deficient in premature infants.

Adult↗

The role of absorption, distribution, metabolism, excretion and toxicity in drug discovery.

Major reasons preventing many early candidates reaching market are the inappropriate ADME (absorption, distribution, metabolism and excretion) properties and drug-induced toxicity. From a commercial perspective, it is desirable that poorly behaved compounds are removed early in the discovery phase rather than during the more costly drug development phases. As a consequence, over the past decade, ADME and toxicity (ADMET) screening studies have been incorporated earlier in the drug discovery phase. The intent of this review is to introduce the desirable attributes of a new chemical entity (NCE) to the medicinal chemist from an ADMET perspective. Fundamental concepts, key tools, reagents and experimental approaches used by the drug metabolism scientist to aid a modern project team in predicting human pharmacokinetics and assessing the "drug-like" molecule are discussed.

Absorption↗

[Interactive pathway of ARF-mdm2-p53].

The inhibitor of cyclin-dependent kinase 4-p16INK4 alpha and its alterative reading frame (ARF)-INK4/ARF gene locates at CDKN2A locus of human chromosome 9p21. This locus encodes two overlapped genes: ARF gene and p16INK4 alpha. The amino acid sequences of two genes are completely different because they are encoded by alternative reading frames. ARF participates in the regulation of mdm2-p53 pathway by mdm2. Recent studies showed that ARF gene may play a role in tumorigenesis; the ARF gene promoter hypermethylation may be the principal mechanism in the inactivation of this gene. Here is a review of ARF-mdm2-p53 interacting pathway.

Alternative Splicing↗

[The role of hepatitis B virus X gene and p53 on hepatocellular carcinoma cell growth].

OBJECTIVE: To explore the effects of hepatitis B virus X gene and p53 on hepatocellular growth. METHODS: Two kinds of plasmids containing sense and antisense human wild p53 gene respectively were constructed. SMMU-7721 cells were transfected with HBx, sense-wtp53 antisense-wtp53 separately or cotransfected with either HBx and sense-wtp53 or HBx and antisense-wtp53. Flow cytometry was adopted to measure the apoptosis rates and the effects of HBx on cell cycle progression. The activity of p21(Waf1) promoter-luciferase construct was detected. Growth curves for SMMU-7721 stably transfected with pcDNA3 and pcDNA3HBx were analyzed. RESULTS: After doxorubicin administration, HBx was noticed able to initiate apoptosis of the liver cells. The apoptosis rate was 5.32% in the pcDNA3 transfected and 12.66% in the pcDNA3HBx transfected groups respectively. HBx could also abrogate p53-mediated apoptosis. The apoptosis rate in groups transfected with pcDNA3, pcDNA3wtp53 and pcDNA3HBx + pcDNA3wtp53 was 5.32%, 11.72% and 4.67% respectively. In compared with the normal group, the number of cells in transiently HBx-expressed group and HBx-transfected group decreased 4.79% and 10.25% respectively. HBx inhibited the activity of p21(Waf1) promoter-luciferase constructed (P < 0.05) and promoted cell growth. The growth rate of HBx expression cells was faster. CONCLUSION: Under DNA damage, HBx reduced expression of p21(Waf1) by repressing the activity of p53 protein, followed by disturbing the regulation of G(0)-G(1) cell cycle checkpoint, and promoted the growth rate of hepatoma cells.

Apoptosis↗

[Survey research of serum anti-influenza virus antibody levels in Chinese young people during 1997-2000].

AIM: To survery the levels of serum anti-influenza virus antibodies and variable extent of the virus in the young people. METHODS: The levels of anti-influenza virus antibody in the serum samples collected from 3 000 young people of eight different areas in China in spring and autumn per year during 1997-2000 were detected by microhemagglutination inhibition test. RESULTS: The antibody levels of the young people fluctuated between the spring and autumn per year. The levels of antibody against type A3 virus (H3N2) preserved high from 1999-2000, while the level of antibody to type A1 (H1N1) decreased from 1998 to 2000 and the percentages of people susceptible to this type rose from 15% to 75%. CONCLUSION: The epidemic of H3N2, H1N1 viruses and influenza virus type has occurred at some areas in China. Significant variation appeared in H1N1 virus, while the variation of H3N2 virus will be expected.

Antibodies, Viral↗

Fluorescent sensors for the enantioselective recognition of mandelic acid: signal amplification by dendritic branching.

Novel chiral bisbinaphthyl compounds have been synthesized for the enantioselective fluorescent recognition of mandelic acid. By introducing dendritic branches to the chiral receptor unit, the fluorescence signals of the receptors are significantly amplified because of the light-harvesting effect of the dendritic structure. This has greatly increased the sensitivity of the sensors in the fluorescent recognition. Study of the three generation sensors demonstrates that the generation zero sensor is the best choice for the recognition of mandelic acid because of its greatly increased fluorescence signal over the core and its high enantioselectivity. This sensor is potentially useful for the high throughput screening of chiral catalysts for the asymmetric synthesis of alpha-hydroxycarboxylic acids.

Fluorescent Dyes↗

Bisbinaphthyl macrocycle-based highly enantioselective fluorescent sensors for alpha-hydroxycarboxylic acids.

[structure: see text] Bisbinaphthyl-based macrocycles are found to carry out highly enantioselective fluorescent recognition of alpha-hydroxycarboxylic acids. It is observed that within a certain concentration range, one enantiomer of the chiral acids can increase the fluorescence intensity of the macrocycles by 2-3-fold, while the other enantiomer scarcely enhances the fluorescence. Such unusually high enantioselective responses make these macrocycles very attractive as fluorescent sensors in determining the enantiomeric composition of alpha-hydroxycarboxylic acids.

Acids, Heterocyclic↗