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Targeted Mass Spectrometry Enables Multiplexed Quantification of Immunomodulatory Proteins in Clinical Biospecimens. Front Immunol 2021; 12:765898. [PMID: 34858420 PMCID: PMC8632241 DOI: 10.3389/fimmu.2021.765898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/22/2021] [Indexed: 12/11/2022] Open
Abstract
Immunotherapies are revolutionizing cancer care, producing durable responses and potentially cures in a subset of patients. However, response rates are low for most tumors, grade 3/4 toxicities are not uncommon, and our current understanding of tumor immunobiology is incomplete. While hundreds of immunomodulatory proteins in the tumor microenvironment shape the anti-tumor response, few of them can be reliably quantified. To address this need, we developed a multiplex panel of targeted proteomic assays targeting 52 peptides representing 46 proteins using peptide immunoaffinity enrichment coupled to multiple reaction monitoring-mass spectrometry. We validated the assays in tissue and plasma matrices, where performance figures of merit showed over 3 orders of dynamic range and median inter-day CVs of 5.2% (tissue) and 21% (plasma). A feasibility study in clinical biospecimens showed detection of 48/52 peptides in frozen tissue and 38/52 peptides in plasma. The assays are publicly available as a resource for the research community.
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An objective analysis of quality and readability of online information on COVID-19. HEALTH AND TECHNOLOGY 2021; 11:1093-1099. [PMID: 34189011 PMCID: PMC8222704 DOI: 10.1007/s12553-021-00574-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/16/2021] [Indexed: 01/04/2023]
Abstract
High quality, readable health information is vital to mitigate the impact of the COVID-19 pandemic. The aim of this study was to assess the quality and readability of online COVID-19 information using 6 validated tools. This is a cross-sectional study. "COVID-19" was searched across the three most popular English language search engines. Quality was evaluated using the DISCERN score, Journal of the American Medical Association benchmark criteria and Health On the Net Foundation Code of Conduct. Readability was assessed using the Flesch Reading Ease Score, Flesch-Kincaid Grade Level and Gunning-Fog Index. 41 websites were suitable for analysis. 9.8% fulfilled all JAMA criteria. Only one website was HONCode certified. Mean DISCERN score was 47.8/80 ("fair"). This was highest in websites published by a professional society/medical journal/healthcare provider. Readability varied from an 8th to 12th grade level. The overall quality of online COVID-19 information was "fair". Much of this information was above the recommended 5th to 6th grade level, impeding access for many.
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Awareness and knowledge of Human papillomavirus (HPV) among ethnically diverse women varying in generation status. J Immigr Minor Health 2016; 17:29-36. [PMID: 24052478 DOI: 10.1007/s10903-013-9913-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although Human papillomavirus (HPV) is a common sexually transmitted infection, there is limited knowledge of HPV with ethnic/racial minorities experiencing the greatest disparities. This cross-sectional study used the most recent available data from the California Health Interview Survey to assess disparities in awareness and knowledge of HPV among ethnically/racially diverse women varying in generation status (N = 19,928). Generation status emerged as a significant predictor of HPV awareness across ethnic/racial groups, with 1st generation Asian-Americans and 1st and 2nd generation Latinas reporting the least awareness when compared to same-generation White counterparts. Also, generation status was a significant predictor of HPV knowledge, but only for Asian-Americans. Regardless of ethnicity/race, 1st generation women reported lowest HPV knowledge when compared to 2nd and 3rd generation women. These findings underscore the importance of looking at differences within and across ethnic/racial groups to identify sub-groups at greatest risk for poor health outcomes. In particular, we found generation status to be an important yet often overlooked factor in the identification of health disparities.
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In vivo investigation of escitalopram's allosteric site on the serotonin transporter. Pharmacol Biochem Behav 2015; 141:50-7. [PMID: 26621784 DOI: 10.1016/j.pbb.2015.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
Abstract
Escitalopram is a commonly prescribed antidepressant of the selective serotonin reuptake inhibitor class. Clinical evidence and mapping of the serotonin transporter (SERT) identified that escitalopram, in addition to its binding to a primary uptake-blocking site, is capable of binding to the SERT via an allosteric site that is hypothesized to alter escitalopram's kinetics at the SERT. The studies reported here examined the in vivo role of the SERT allosteric site in escitalopram action. A knockin mouse model that possesses an allosteric-null SERT was developed. Autoradiographic studies indicated that the knockin protein was expressed at a lower density than endogenous mouse SERT (approximately 10-30% of endogenous mouse SERT), but the knockin mice are a viable tool to study the allosteric site. Microdialysis studies in the ventral hippocampus found no measurable decrease in extracellular serotonin response after local escitalopram challenge in mice without the allosteric site compared to mice with the site (p=0.297). In marble burying assays there was a modest effect of the absence of the allosteric site, with a larger systemic dose of escitalopram (10-fold) necessary for the same effect as in mice with intact SERT (p=0.023). However, there was no effect of the allosteric site in the tail suspension test. Together these data suggest that there may be a regional specificity in the role of the allosteric site. The lack of a robust effect overall suggests that the role of the allosteric site for escitalopram on the SERT may not produce meaningful in vivo effects.
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In vivo dialysis setup with a loop injection valve facilitates retrodialysis studies. J Pharmacol Toxicol Methods 2013; 68:217-224. [PMID: 23831608 DOI: 10.1016/j.vascn.2013.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/24/2013] [Accepted: 06/27/2013] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Retrodialysis, as used in neuropharmacological research, is a technique for in vivo delivery of neuroactive agents with concurrent monitoring of their effects on cellular activity with a separation between certain degree of spatial and temporal resolution. Typically, this is accomplished either by the use of a liquid-switch requiring multiple pumps, or by exchange of flow tubing requiring stopping and restarting dialysis. In the present study, we describe the use of a medium pressure injection valve for retrodialysis that overcomes these problems. METHODS The valve was configured with a loop to deliver 20μL of solution, and artificial CSF flow from the pump to the probe was established via this device. The application of this setup was evaluated in urethane anesthetized adult male C57BL/6J mice prepared with a CMA 11 probe implanted in the ventral hippocampus. By switching between the load and inject positions, the loop was filled with escitalopram solution (0.3μM) and delivered at a rate of 1μL/min at the probe for retrodialysis. Escitalopram (2mg/kg BW) was administered subcutaneously for microdialysis studies. During these treatments, dialysate fractions were collected for the determination of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). RESULTS Irrespective of route of escitalopram administration, the pattern of dialysate 5-HT, and 5-HIAA response was comparable to that reported by other investigators. Accordingly, the in-line valve assembly did not compromise retrodialysis or microdialysis sampling. The manipulations to carry out retrodialysis using the valve setup are easy and simple. DISCUSSION An in-line injection valve is a promising adaptation for retrodialysis studies and can be incorporated as a standard part of in vivo dialysis instrumentation.
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The reaction of methyl sterculate and malvalate with silver nitrate-silica gel and its use as a basis for the estimation of cyclopropene fatty acids. Lipids 2012; 2:316-22. [PMID: 17805758 DOI: 10.1007/bf02532118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/1966] [Indexed: 10/23/2022]
Abstract
When in contact with silver nitratesilica gel, methyl esters of cyclopropene fatty acids undergo ring opening to yield pairs of isomers with methylene, hydroxymethyl, or nitratomethyl side-chains at the original ring positions. Thus the main products from methyl sterculate were the methyl 9 (or 10)-methylene octadec-10 (or 8)-enoates, and, in lesser quantities, the methyl 9 (or 10)-(nitratomethyl)-octadec-9-enoates and the methyl 9 (or 10)-(hydroxymethyl)-octadec-9-enoates. Hydrogenation quantitatively converted this mixture of isomeric pairs to a mixture of methyl 9- and methyl 10-methyloctadecanoates.Chromatography on silver nitrate-silica gel, followed by gas chromatography of the hydrogenated products, has been used as the basis of a new method for estimating individual cyclopropene and cyclopropane acids in lipids.
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Abstract
BACKGROUND Observations that diabetics treated with biguanide drugs have a reduced risk of developing cancer have prompted an enthusiasm for these agents as anti-cancer therapies. We sought to determine the efficacy of the biguanide phenformin in the chemoprophylaxis and in the treatment of oestrogen receptor (ER)-positive MCF7 and receptor triple-negative MDAMB231 xenografts in immunocompromised mice. We also compared the efficacy of phenformin and metformin in the treatment of MDAMB231. METHODS Immunocompromised mice were divided into groups: (1) phenformin administered for 2 weeks prior to cell injection; (2) established tumours treated with phenformin; (3) established tumours treated with metformin (only for MDAMB231 tumours); (4) untreated controls. Post-treatment tumours, liver and spleen were harvested for further analysis. RESULTS Phenformin significantly inhibited both the development and growth of MCF7 and MDAMB231 tumours, and for MDAMB231 at greater efficacy than metformin without murine toxicity. The number of mitotic figures was significantly fewer in xenografts treated with phenformin compared with controls. Results suggested that the mechanism of action of phenformin in vivo is consistent with AMPK activation. CONCLUSION Phenformin has clinical potential as an antineoplastic agent and should be considered for clinical trials both in ER-positive and triple-negative breast cancer.
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Abstract P1-03-07: Differential Effect of Specific p53 Mutations on Breast Cancer Growth and Response to Hsp90 Inhibition In Vivo. Cancer Res 2010. [DOI: 10.1158/0008-5472.sabcs10-p1-03-07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background p53 mutation influences breast cancer cell growth and patient prognosis. However, different p53 mutations impart specific functions to the mutant protein, including dominant negative or gain of function effects. Mutant p53 molecules R273H and R175H are commonly found in primary breast cancers and are present in the MDA-MB-468 and SKBR3 cell lines, respectively. To compare the direct effects of these two mutations in vivo in an identical cellular background, H1299 (p53-null) cells were constructed to express R273H or R175H p53 mutants. Methods
Thirty female SCID mice were injected subcutaneously with 106 H1299 (p53-null), H1299/R273H or H1299/R175H cells in DMEM + Matrigel (50:50) suspension. Some mice were treated with an Hsp90 inhibitor, which is required for correct folding of many oncogenic proteins. Results
Xenografts bearing R175H showed a mean lag phase (time between cell injection and tumors at exponential growth) of 21 days and a doubling time of 5 days, whereas tumors bearing H1299 (p53-null) or R273H mutation had a lag phase of 31 days with a doubling time of 7 days. Immunohistochemical examination demonstrated a highly heterogeneous pattern of p53 protein expression in the more aggressive R175H expressing cells compared with R273H expressing cells. Hsp90 inhibitor treatment reduced the growth of H1299 and R273H cells, but not R175H cells. Conclusions
The specific p53 mutations directly influence the rate of tumor growth and the p53 protein staining pattern on immunohistochemistry. The differential effects of specific p53 mutations should be considered when interpreting clinical data involving p53 mutation such as in the EORTC 10994 trial, with implications for prognostic determination of individual breast cancer patients.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-03-07.
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Seliciclib (CYC202, R-roscovitine) enhances the antitumor effect of doxorubicin in vivo in a breast cancer xenograft model. Int J Cancer 2009; 124:465-72. [PMID: 19003963 DOI: 10.1002/ijc.23938] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We sought to determine whether seliciclib (CYC202, R-roscovitine) could increase the antitumor effects of doxorubicin, with no increase in toxicity, in an MCF7 breast cancer xenograft model. The efficacy of seliciclib combined with doxorubicin was compared with single agent doxorubicin or seliciclib administered to MCF7 cells and to nude mice bearing established MCF7 xenografts. Post-treatment cells and tumors were examined by cell cycle analysis, immunohistochemistry and real-time PCR. Seliciclib significantly enhanced the antitumor effect of doxorubicin without additional murine toxicity. MIB1 (ki67) immunohistochemistry demonstrated reduced proliferation with treatment. The levels of p21 and p27 increased after treatment with doxorubicin or seliciclib alone or in combination, compared to untreated controls. However, no changes in p53 protein (DO1, CM1), survivin or p53 phosphorylation (SER15) were observed in treated tumors compared with controls. In conclusion, the CDK inhibitor seliciclib (R-roscovitine) enhances the antitumor effect of doxorubicin in MCF7 tumors without increased toxicity with a mechanism that involves cell cycle arrest rather than apoptosis.
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Sorption behavior of a synthetic antioxidant, polycyclic musk, and an organophosphate insecticide in wastewater sludge. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2009; 60:145-154. [PMID: 19587412 DOI: 10.2166/wst.2009.284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Emerging contaminants (ECs) are chemicals that are currently unregulated due to limited understanding of health effects and limited data regarding occurrence. Wastewater treatment plants (WWTP) receive many ECs as components of influent waste and the removal of organic contaminants, such as ECs, occurs primarily by sorption to sludge. Therefore, it is important to develop measures of sorption behavior by ECs to sludge. This study evaluates sorption of three ECs: 3-tert-butyl-4-hydroxyanisole (BHA) a synthetic antioxidant, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta(g)-2-benzopyrane (HHCB) a polycyclic musk, and chlorpyrifos a organophosphate insecticide. Twenty-four hour laboratory-scale sorption experiments were conducted for each compound individually and then in combination, which allowed the quantification of sorption onto wastewater sludge and the affects of multiple compounds. ECs in both the liquid and solid phases were analyzed using a gas chromatograph with flame ionization detector (GC/FID). Isotherms of individual sorption behavior followed a linear trend (R2 > 0.9) for individual ECs, while K(d) averaged 2,689 L kg(-1), 27,786 L kg(-1) and 31,402 L kg(-1) for BHA, chlorpyrifos and HHCB, respectively. Sorption behavior for BHA was linear during combined studies with K(d) of 1,766 L kg(-1) or a decrease of 34%, while HHCB and chlorpyrifos followed non-linear isotherm models. Synergistic effects were observed with spike concentrations > or =25 mg L(-1) for HHCB and > or =20 mg L(-1) for chlorpyrifos. K(d) values ranged from 16,984-6,000,000 L kg(-1) for HHCB and 19,536-3,000,000 L kg(-1) for chlorpyrifos. These distribution coefficients differed substantially from previously published values, mainly because few studies used sludge as the sorption media. Results suggest that HHCB and chlorpyrifos may be contained in the sludge unlike BHA, which is more available in the aqueous phase. Future investigations should evaluate WWTP processes for degrading ECs to harmless products and releases of ECs from sludge.
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Characterization, chemical optimization and anti-tumour activity of a tubulin poison identified by a p53-based phenotypic screen. Cell Cycle 2008; 7:3417-27. [PMID: 18971638 DOI: 10.4161/cc.7.21.6982] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A robust p53 cell-based assay that exploits p53's function as a transcription factor was used to screen a small molecule library and identify bioactive small molecules with potential antitumor activity. Unexpectedly, the majority of the highest ranking hit compounds from this screen arrest cells in mitosis and most of them impair polymerization of tubulin in cells and in vitro. One of these novel compounds, JJ78:1, was subjected to structure-activity relationship studies and optimized leading to the identification of JJ78:12. This molecule is significantly more potent than the original hit JJ78:1, as it is active in cells at two-digit nanomolar concentrations and shows clear antitumor activity in a mouse xenograft model as a single agent. The effects of nocodazole, a well established tubulin poison, and JJ78:12 on p53 levels are remarkably similar, supporting that tubulin depolymerization is the main mechanism by which JJ78:12 treatment leads to p53 activation in cells. In summary, these results identify JJ78:12 as a potential cancer therapeutic, demonstrate that screening for activators of p53 in a cell-based assay is an effective way to identify inhibitors of mitosis progression and highlights p53's sensitivity to alterations during mitosis.
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Discovery, in vivo activity, and mechanism of action of a small-molecule p53 activator. Cancer Cell 2008; 13:454-63. [PMID: 18455128 PMCID: PMC2742717 DOI: 10.1016/j.ccr.2008.03.004] [Citation(s) in RCA: 382] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 12/05/2007] [Accepted: 03/06/2008] [Indexed: 12/20/2022]
Abstract
We have carried out a cell-based screen aimed at discovering small molecules that activate p53 and have the potential to decrease tumor growth. Here, we describe one of our hit compounds, tenovin-1, along with a more water-soluble analog, tenovin-6. Via a yeast genetic screen, biochemical assays, and target validation studies in mammalian cells, we show that tenovins act through inhibition of the protein-deacetylating activities of SirT1 and SirT2, two important members of the sirtuin family. Tenovins are active on mammalian cells at one-digit micromolar concentrations and decrease tumor growth in vivo as single agents. This underscores the utility of these compounds as biological tools for the study of sirtuin function as well as their potential therapeutic interest.
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High Performance Thin Layer Chromatographic Analysis of Neutral Lipids in the Feces of BALB/c Mice Infected withEchinostoma caproni. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701277034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
The majority of human tumors bear inactive p53 or cellular factors that down-regulate the expression and activity of the p53 network. Therefore, finding therapies that are effective in such tumors is of great interest. Usnic acid, a normal component of lichens, showed activity against the wild-type p53 breast cancer cell line MCF7 as well as the non-functional p53 breast cancer cell line MDA-MB-231 and the lung cancer cell line H1299 (null for p53). In MCF7 cells treated with usnic acid, although there was an accumulation of p53 and p21 proteins, the transcriptional activity of p53 remained unaffected. We also found that there was no phosphorylation of p53 at Ser15 after treatment of MCF7 cells with usnic acid, suggesting that the oxidative stress and disruption of the normal metabolic processes of cells triggered by usnic acid does not involve DNA damage. The property of usnic acid as a non-genotoxic anti-cancer agent that works in a p53-independent manner makes it a potential candidate for novel cancer therapy.
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Abstract
The efficacy of MDI-301, a non-toxic novel synthetic retinoid, was found to be equivalent to the natural 9-cis-retinoic acid (RA) in vitro against estrogen-dependent MCF7 and T47D breast cancer cell lines which express RA receptor (RAR) alpha. Both retinoids also showed similar efficacy against established PC-3 prostate carcinoma xenografts. MCF7 tumor xenografts showed a reduction in tumor growth of 48% without systemic side-effects upon treatment with MDI-301 compared with MCF7 controls. Tumor xenografts derived from MDA-MB-231, an estrogen-independent breast cancer cell line that expresses low levels of RARalpha, were unresponsive. This study demonstrates that MDI-301 is as efficacious as 9-cis-RA against cancer cells with RARalpha, with no signs of toxicity in vivo, making it a potential candidate for cancer therapy.
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Poliovirus 5'-terminal cloverleaf RNA is required in cis for VPg uridylylation and the initiation of negative-strand RNA synthesis. J Virol 2001; 75:10696-708. [PMID: 11602711 PMCID: PMC114651 DOI: 10.1128/jvi.75.22.10696-10708.2001] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chimeric poliovirus RNAs, possessing the 5' nontranslated region (NTR) of hepatitis C virus in place of the 5' NTR of poliovirus, were used to examine the role of the poliovirus 5' NTR in viral replication. The chimeric viral RNAs were incubated in cell-free reaction mixtures capable of supporting the sequential translation and replication of poliovirus RNA. Using preinitiation RNA replication complexes formed in these reactions, we demonstrated that the 3' NTR of poliovirus RNA was insufficient, by itself, to recruit the viral replication proteins required for negative-strand RNA synthesis. The 5'-terminal cloverleaf of poliovirus RNA was required in cis to form functional preinitiation RNA replication complexes capable of uridylylating VPg and initiating the synthesis of negative-strand RNA. These results are consistent with a model in which the 5'-terminal cloverleaf and 3' NTRs of poliovirus RNA interact via temporally dynamic ribonucleoprotein complexes to coordinately mediate and regulate the sequential translation and replication of poliovirus RNA.
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Abstract
The 5'-terminal 88 nt of poliovirus RNA fold into a cloverleaf RNA structure and form ribonucleoprotein complexes with poly(rC) binding proteins (PCBPs; AV Gamarnik, R Andino, RNA, 1997, 3:882-892; TB Parsley, JS Towner, LB Blyn, E Ehrenfeld, BL Semler, RNA, 1997, 3:1124-1134). To determine the functional role of these ribonucleoprotein complexes in poliovirus replication, HeLa S10 translation-replication reactions were used to quantitatively assay poliovirus mRNA stability, poliovirus mRNA translation, and poliovirus negative-strand RNA synthesis. Ribohomopoly(C) RNA competitor rendered wild-type poliovirus mRNA unstable in these reactions. A 5'-terminal 7-methylguanosine cap prevented the degradation of wild-type poliovirus mRNA in the presence of ribohomopoly(C) competitor. Ribohomopoly(A), -(G), and -(U) did not adversely affect poliovirus mRNA stability. Ribohomopoly(C) competitor RNA inhibited the translation of poliovirus mRNA but did not inhibit poliovirus negative-strand RNA synthesis when poliovirus replication proteins were provided in trans using a chimeric helper mRNA possessing the hepatitis C virus IRES. A C24A mutation prevented UV crosslinking of PCBPs to 5' cloverleaf RNA and rendered poliovirus mRNA unstable. A 5'-terminal 7-methylguanosine cap blocked the degradation of C24A mutant poliovirus mRNA. The C24A mutation did not inhibit the translation of poliovirus mRNA nor diminish viral negative-strand RNA synthesis relative to wild-type RNA. These data support the conclusion that poly(rC) binding protein(s) mediate the stability of poliovirus mRNA by binding to the 5'-terminal cloverleaf structure of poliovirus mRNA. Because of the general conservation of 5' cloverleaf RNA sequences among picornaviruses, including C24 in loop b of the cloverleaf, we suggest that viral mRNA stability of polioviruses, coxsackieviruses, echoviruses, and rhinoviruses is mediated by interactions between PCBPs and 5' cloverleaf RNA.
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Abstract
Although the myelin membrane contains only a small set of major proteins, more sensitive assays indicate the presence of a plethora of uncharacterized proteins. We have used an antibody perturbation approach to reversibly block the differentiation of prooligodendroblasts into myelinating cells, and, in combination with a differential screening procedure, identified novel mRNAs that are activated during this period. One cDNA, TPO1, recognizes a 5.5-kb mRNA that is strongly up-regulated in oligodendrocytes after release of the differentiation block and that is expressed at high levels in brain tissue during active myelination. This cDNA represents at least two mRNAs differing from each other in their 5'-termini. The TPO1 cDNA contains an open reading frame of 1,380 bp, encoding a protein of 51.8 kDa with a predicted pI of 9.1 that contains two regions homologous to nonclassic zinc finger motifs. Subcellular localization studies suggest the enriched presence of TPO1 in spherical structures along the major cytoplasmic processes of oligodendrocytes. TPO1, along with homologues expressed in testis, placenta, and PC12 cells, form a novel family of proteins with multiple hydrophobic domains possibly serving as membrane spanning regions. We postulate that in oligodendrocytes, TPO1 encodes a protein factor involved in myelin biogenesis.
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Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: modeling of a single, long pulse length comparison. APPLIED OPTICS 1997; 36:3363-3374. [PMID: 18253350 DOI: 10.1364/ao.36.003363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two methods of producing the long pulse lengths that promote efficient extraction of energy from low-gain, quasi-four-level lasers are analyzed. A long pulse length output can mitigate laser-induced damage effects and can be generated in quasi-four-level lasers by two disparate methods. One method utilizes Q-switching techniques in resonators designed to extend the pulse length and another utilizes the first pulse in a relaxation oscillation pulse train. Models for quasi-four-level lasers are derived here taking into account the nonnegligible thermal population of the lower laser level. Closed-form expressions are derived for both modes of operation of quasi-four-level laser systems so the parametric dependencies of both forms of operation become obvious, allowing facile comparison. In addition, a combined absorption and quantum efficiency, germane for flash-lamp pumping, is calculated for both Cr and Er sensitizers. Although the former has the advantage of broad absorption bands, the latter has the advantage of a quantum efficiency approaching 3.
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Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: experimental results of a single, long pulse length comparison. APPLIED OPTICS 1997; 36:3357-3362. [PMID: 18253349 DOI: 10.1364/ao.36.003357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Flash-lamp-pumped, room-temperature Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF are compared for single but long pulse operation, with pulse lengths of approximately 1.0 mus. Under similar operating conditions in normal-mode operation, a slope efficiency of 0.0331 was observed for Ho:Tm:Er:YLF compared with 0.0047 for Ho:Tm:Cr:YAG. For Q-switched operation, Ho:Tm:Er:YLF yielded a slope efficiency of 0.0075. In comparison, a slope efficiency of 0.0012 was obtained for Ho:Tm:Cr:YAG. Two methods of producing long pulse lengths are compared: pulse selection of normal-mode relaxation oscillations and Q-switching in a long resonator. Theoretical models developed in a companion paper for normal-mode relaxation oscillations and Q-switching in quasi-four-level solid-state lasers are in agreement with the experimental results.
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Abstract
An optical efficiency of 0.052 under normal mode operation for diode-pumped Ho:Tm:YLiF(4) at a pulse repetition frequency of 10 Hz has been achieved. Laser output energy of 30 mJ in single Q-switched pulses with 600-ns pulse length were obtained for an input energy of 3 J. A diffusion-bonded birefringent laser rod consisting of Ho:Tm-doped and undoped pieces of YLF was utilized for 10-Hz operation.
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Long-pulse-length 2-microm diode-pumped YLiF(4) laser. OPTICS LETTERS 1993; 18:1636-1638. [PMID: 19823470 DOI: 10.1364/ol.18.001636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Abstract
N-acyl and acetoxy derivatives of putrescine and cadaverine have been found in the faeces of children and in cultures of isolates of gut bacteria. The evidence was accumulated from two dimensional, thin layer chromatography, field desorption mass spectrometry, and accurate mass measurement of the DANS derivatives of the amines. The acetoxy compounds of putrescine and cadaverine have not previously been reported.
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Determination of simple phenols in faeces and urine by high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1988; 431:143-9. [PMID: 3235525 DOI: 10.1016/s0378-4347(00)83077-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Abstract
The free primary amines present in the faeces of 44 infants (1-18 months) with gastroenteritis have been examined by field desorption mass spectrometry of the lactone form of their fluorescamine derivatives without their prior separation. p-Tyramine, 2-phenylethylamine, the diamines, putrescine and cadaverine and several of their acyl derivatives were common constituents, but a number of other amines were also characterised. Using thin layer chromatography and field desorption mass spectrometry of the amine dansyl derivatives a comparative study was made of the faecal amines of 13 selected infants with gastroenteritis (diarrhoea) and of 13 healthy infants. p-Tyramine, the most abundant amine, was significantly higher (p = 0.02) in the sick infants. The overall presence of p-tyramine was more significantly related to the diet of the infants. Faecal tyramine was low in breast fed infants but significantly higher (p = 0.01) in infants fed cow's milk.
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27
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Concentration of headspace, airborne and aqueous volatiles on Chromosorb 105 for examination by gas chromatography and gas chromatography-mass spectrometry. J Chromatogr A 1977; 135:49-60. [PMID: 856863 DOI: 10.1016/s0021-9673(00)86300-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Techniques are described for the collection of volatile material from headspace vapours and the atmosphere and for the direct extraction of volatiles from aqueous solution by traps containing the porous polymer Chromosorb 105. The traps are inserted through a valve into a gas chromatograph which facilitates the desorption and transfer of the volatiles to high-resolution capillary columns. Selected applications of the technique are described.
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The chemistry of food flavour. I. Volatile constituents of passionfruit, Passiflora edulis. Aust J Chem 1972. [DOI: 10.1071/ch9721921] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The volatile constituents
of the purple-skinned passionfruit (Passifora edulis Sims)
have been investigated. The volatiles were concentrated, fractionated by gas
chromatography and chromatography on silica gel, and the resulting fractions
examined by combined gas chromatography-mass spectrometry. The majority of the
components identified are esters derived largely from combinations of the
alkan-1-ols (C1,2,4,6,8) the alkan-2-ols (C5,7),(Z)-and
(E)-hex-3-en-1-ol,(2)-hex-4-en-1-ol,and benzyl alcohol, with acids of even carbon
number (acetic, butanoic, hexanoic, octanoic, hex-3-enoic, oct-3-enoic, and 3-hydroxyhexanoic).
The non-ester constituents include many of the above free alcohols,
acetaldehyde, alkan-2-ones (C3,5,7,9,11), monoterpenes
((E)-β-ocimene, 1,8-cineole, linalool, α-terpineol, citronellol, geraniol, citronellyl acetate,
(Z) and(E) five-membered ring linalool oxides), and 1,1,6-trimethyl-
l,2-dihydronaphthalene, β-ionone, γ-hexanolac-tone,
γ-octanolactone, and the lactone of
2-hydroxy-2,6,6-trimethylcyclohexylidene- acetic acid. Preliminary odour
assessment of the constituents has indicated that volatile passionfruit flavour
is complex. Many components, especially certain esters, are clearly important
and one component, not yet completely characterized, may have particular
significance.
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30
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Studies on a kerosene-like taint in mullet (Mugil cephalus). II. Chemical nature of the vvolatile constituents. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 1970; 21:433-436. [PMID: 5472927 DOI: 10.1002/jsfa.2740210811] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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31
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2-methoxypyrazines and the flavour of green peas (Pisum sativum). Chem Ind 1970; 27:897-8. [PMID: 5428022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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32
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Abstract
The isolation of a pure
sesquiterpene hydrocarbon from the natural coating of Granny Smith apples is
described. Evidence mainly from its ultraviolet, infrared, mass, and N.M.R.
spectra establish it as an α- farnesene stereoisomer (I) with a trans
configuration assigned to the 9,10 double bond and a likely trans configuration
of the 6,7 bond. Its infrared, mass, and N.M.R. spectra and those of
trans-β-farnesene (II) are reported.
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33
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34
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35
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Investigations of suint. II. The positive identification of some constituent organic acids. Aust J Chem 1964. [DOI: 10.1071/ch9640070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Chiefly by the use of gas chromatography
and mass spectrometry the following acids have been positively identified as
constituents of the suint from a crossbred Merino fleece: Acetic, propionic,
butyric, valeric, hexanoic, isobutyric, 2-methylbutyric, 3-methylbutyric,
2-methylvaleric, succinic, glutaric, α-hydroxyglutaric, α-ketoglutaric,
benzoic, and phenylacetic.
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36
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Abstract
Largely by the use of gas chromatographic
techniques the two main constituent acids of the preen gland wax of the goose
have been isolated and shown to be 2,4,6,8-tetramethyldecanoic and
2,4,6,8-tetramethylundecanoic acids.
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37
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Investigations of Suint. I. The Composition of the Organic Acids from Fleeces of Different Origin. Aust J Chem 1962. [DOI: 10.1071/ch9620832] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A major part of the organic acids of the
suint from each of seven samples of wool fleece of different origin has been
examined by gas chromatography of the methyl esters. Twenty-three acids have
been identified in one or more of the samples by the retention times of the
esters. The composition of all samples was complex and differed considerably
both quantitatively and qualitatively.
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38
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Abstract
A quantitative examination has been made of the components of
hydrolysed beeswax. This was achieved by separation into hydrocarbons,
monohydric alcohols, " diols ",acids, and hydroxyacids. The alcohol
and acid fractions were reduced to the corresponding hydrocarbon mixtures and
these together with the naturally occurring hydrocarbons were examined by gas
chromatography, which demonstrated their straight-chain character and gave the
chain lengths and percentage composition of the components.
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39
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Studies in Waxes. XX. The Quantitative Analysis of Hydrolysed Carnauba Wax by Gas Chromatography. Aust J Chem 1961. [DOI: 10.1071/ch9610619] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The hydrolytic products of carnauba wax,
previously shown to consist mainly of straight-chain alcohols, α,ω-diols, alkanoic acids, and ω-hydroxyalkanoic
acids, have been reexamined by gas chromatographic methods to provide a
qualitative and quantitative knowledge of the components. These components,
shown to be almost entirely straight chain in character, are largely even
carbon numbered compounds, but odd chain-lengths are present. The hydrocarbons
are likewise of odd and even carbon number with the odd members (90%)
predominating.
An unidentified compound, possibly an
unsaturated steroid diol, has been isolated from the unsaponifiable fraction.
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40
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Abstract
The stem wax of the grass Leptochloa
digitata (R.Br.) Domin. has been examined mainly by gas chromatographic
methods. The wax after hydrolysis has been shown to consist largely of
straight-chain acids (54%) and n-paraffin hydrocarbons (21%). Straight-chain
alcohols and ketones are also present, along with other alcohols and ketones
which were not examined.
A feature of the wax is the presence of
small amounts of hydrocarbons with very long chains (2.5%) from which
n-dohexacontane (C62H126) has been isolated and
identified by its X-ray long spacing and melting point.
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41
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Studies in Waxes. XIV. An Investigation of the Aliphatic Constituents of Hydrolysed Wool Wax by Gas Chromatography. Aust J Chem 1960. [DOI: 10.1071/ch9600080] [Citation(s) in RCA: 115] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A quantitative analysis has been made of
the composition of each of the classes of aliphatic constituents known to exist
in hydrolysed wool wax. These classes consist of α-hydroxy acids, ω-hydroxy
acids, alkanoic acids, monohydric alcohols, and α,β-diols. Each has
been found to contain members of the normal, iso-, and anteiso-homologous
series of compounds.
The analysis was carried out by
saponification of the wax and separation of the constituents into the above
classes which were separately reduced to the corresponding hydrocarbon
mixtures. The composition of these mixtures was determined by gas
chromatographic separation.
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42
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Sugar-Cane Wax. II. An Examination of the Constituents of Sugar-Cane Cuticle Wax by Gas Chromatography. Aust J Chem 1960. [DOI: 10.1071/ch9600498] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Sugar-cane cuticle wax previously found to
consist of long-chain aldehydes, alcohols, acids, and hydrocarbons (Lamberton
and Redcliffe 1960) has been re-examined by gas chromatography to identify and
estimate the individual constituents. The aldehydes, alcohols, and acids, all
straight chain, are principally of even carbon number in each instance with the
C28 member predominant, but appreciable amounts of odd carbon
homologues are also present. The hydrocarbons are also of odd and even carbon
number but with the odd members in greater amounts and n-heptacosane as the
major hydrocarbon constituent.
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Abstract
A method is described for the
determination of the structure of branched-chain fatty acids. It is found that
the carbon chain of methyl-branched acids can be readily degraded by potassium
permanganate in acetone, to give a series of acids of decreasing carbon number.
Where a branch occurs the acid series is interrupted and a methyl ketone, of
the same carbon number as a missing acid, is produced. Gas chromatographic
examination of the ketone(s) and esterified acids gives clear evidence for the
location of the branch(es).
The method is illustrated by application
to tuberculostearic acid (10-methyl-octadecanoic acid) and C27-phthianoic
acid (2,4,6-trimethyltetracosanoic acid). It appears also able to decide the
location of the ring in cyclopropane fatty acids.
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Abstract
Four α-ω-diols have been
isolated from the unsaponifiable fraction of carnauba wax and identified as
n-docosane-1,22-diol, n-tetracosane-1,24-diol, n-hexacosane-1,26-diol, and
n-octacosane-1,28-diol.
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Abstract
Seven ω-hydroxy acids have been
identified as constituents of carnauba wax. They are 18-hydroxyoctadecanoic,
20-hydroxyeicosanoic, 22-hydroxydooosanoic, 24-hydroxytetracosanoic,
26-hydroxyhexacosanoic, 28-hydroxyoctacosanoic, and 30-hydroxytriacontanoic
acids.
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46
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Abstract
Seven normal alcohols have been isolated
from the unsaponifiable part of wool wax and identified as n-octadecanol,
n-eicosanol, n-docosanol, n-tetracosanol, n-hexacosanol, n-octacosanol, and
n-triacontanol.
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Abstract
A study has been made of the direct
oxidation of ethylene to ethylene oxide in a flowing system under the catalytic
action of silver. Various catalysts were prepared and one containing 10 per
cent. barium carbonate, having a high and sustained activity, was selected for
a detailed examination of the influence of reaction conditions on the yield of
ethylene oxide.
It has been found that the percentage
ethylene in the reaction mixture can be varied widely without greatly changing
the yield of ethylene oxide, but that the conversion is decreased by increasing
the ethylene content. The yield increases with increasing oxygen content until
the latter reaches 20 per cent. after which further enrichment with oxygen has
little effect. The presence of water vapour slightly increases the yield, hut
considerably decreases conversion. The yield is much decreased by diminishing
the reaction pressure. Highest yields (73 per cent.) were obtained when small amounts
of ethylene dichloride were added to the reactants but at the expense of low
conversion. Propylene and isobutylene yielded only carbon dioxide and water
when oxidized in the presence of a silver catalyst.
The results are discussed in relation to
the reaction mechanism suggested by Twigg(1).
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