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Jacquet YF, Marks N. The C-fragment of beta-lipotropin: an endogenous neuroleptic or antipsychotogen? Science 1976; 194:632-5. [PMID: 185695 DOI: 10.1126/science.185695] [Citation(s) in RCA: 374] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microinjection of the C-fragment (also called beta-endorphin), which is amino acid sequence 61-91 of the endogenous pituitary hormone, beta-lipotropin (beta-LPH), in the periaqueductal gray of the rat resulted in profound sedation and catalepsy, while microinjection of smaller fragments-that is, methionine-enkephalin [sequence beta-LPH-(61-65)] and its related pentapeptide, leucine enkephalin, and alpha-endorphin [sequence beta-LPH-(61-76)] resulted in attenuated forms of this behavior. This indicates that the C-fragment is an important neuromodulator of the central nervous system. The similarity of this behavior to that seen after systemic administration to experimental animals of exogenous neuroleptics suggests that a disturbance in the bioavailability of this neuropeptide to receptor sites in brain-perhaps due to lack of enzymatic cleavage from the circulating parent hormone, beta-lipotropin--may be an etiological factor in those psychopathological states for which the exogenous neuroleptics exert an ameliorative influence.
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Comparative Study |
49 |
374 |
2
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36 |
168 |
3
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Marks N, Grynabaum A, Neidle A. On the degradation of enkephalins and endorphins by rat and mouse brain extracts. Biochem Biophys Res Commun 1977; 74:1552-9. [PMID: 843378 DOI: 10.1016/0006-291x(77)90619-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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48 |
113 |
4
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Abstract
1. Cerebral proteinases were separated on Sephadex G-100 columns into acid and neutral fractions free from cross-contamination. Acid proteinases were more stable and were purified by additional steps with salt and pH5.0 precipitations, column chromatography on DEAE- or CM-cellulose and free-flow electrophoresis. 2. The separation made it possible to study the properties of the partially purified enzyme fractions. Some of these properties, such as K(m) with selected protein substrates, pH optima and temperature-dependence in the presence and absence of substrates, are described. 3. No requirement for metal ions or added cofactors was demonstrated. Neutral-proteinase activity was more sensitive to inhibition by heavy-metal ions; its activity could be increased by thioglycollate and glutathione, and inhibited by thiol reagents. Neutral and acid proteinases were inhibited by the chymotrypsin inhibitor chloromethyl l-2-phenyl-1-toluene-p-sulphonamidoethyl ketone. 4. In the presence of the appropriate synthetic substrates no cathepsin A activity was found, and only trace quantities of cathepsin B or C activities, which were more than 50-fold less than cathepsin D-like activity.
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Journal Article |
19 |
112 |
5
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Dalzell JJ, McVeigh P, Warnock ND, Mitreva M, Bird DM, Abad P, Fleming CC, Day TA, Mousley A, Marks NJ, Maule AG. RNAi effector diversity in nematodes. PLoS Negl Trop Dis 2011; 5:e1176. [PMID: 21666793 PMCID: PMC3110158 DOI: 10.1371/journal.pntd.0001176] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/04/2011] [Indexed: 11/22/2022] Open
Abstract
While RNA interference (RNAi) has been deployed to facilitate gene function studies in diverse helminths, parasitic nematodes appear variably susceptible. To test if this is due to inter-species differences in RNAi effector complements, we performed a primary sequence similarity survey for orthologs of 77 Caenorhabditis elegans RNAi pathway proteins in 13 nematode species for which genomic or transcriptomic datasets were available, with all outputs subjected to domain-structure verification. Our dataset spanned transcriptomes of Ancylostoma caninum and Oesophagostomum dentatum, and genomes of Trichinella spiralis, Ascaris suum, Brugia malayi, Haemonchus contortus, Meloidogyne hapla, Meloidogyne incognita and Pristionchus pacificus, as well as the Caenorhabditis species C. brenneri, C. briggsae, C. japonica and C. remanei, and revealed that: (i) Most of the C. elegans proteins responsible for uptake and spread of exogenously applied double stranded (ds)RNA are absent from parasitic species, including RNAi-competent plant-nematodes; (ii) The Argonautes (AGOs) responsible for gene expression regulation in C. elegans are broadly conserved, unlike those recruited during the induction of RNAi by exogenous dsRNA; (iii) Secondary Argonautes (SAGOs) are poorly conserved, and the nuclear AGO NRDE-3 was not identified in any parasite; (iv) All five Caenorhabditis spp. possess an expanded RNAi effector repertoire relative to the parasitic nematodes, consistent with the propensity for gene loss in nematode parasites; (v) In spite of the quantitative differences in RNAi effector complements across nematode species, all displayed qualitatively similar coverage of functional protein groups. In summary, we could not identify RNAi effector deficiencies that associate with reduced susceptibility in parasitic nematodes. Indeed, similarities in the RNAi effector complements of RNAi refractory and competent nematode parasites support the broad applicability of this research genetic tool in nematodes. Many organisms regulate gene expression through an RNA interference (RNAi) pathway, first characterized in the nematode Caenorhabditis elegans. This pathway can be triggered experimentally using double-stranded (ds)RNA to selected gene targets, thereby allowing researchers to ‘silence’ individual genes and so investigate their function. It is hoped that this technology will facilitate gene silencing in important parasitic nematodes that impose a considerable health and economic burden on mankind. Unfortunately, differences in RNAi susceptibility have been observed between species. Here we investigated the possibility that differences in the complement of effector proteins involved in the RNAi pathway are responsible for these differences in susceptibility. Our data revealed that most facets of the RNAi pathway are well represented across parasitic nematodes, although there were fewer pathway proteins in other nematodes compared to C. elegans. In contrast, the proteins responsible for uptake and spread of dsRNA are not well represented in parasitic nematodes. However, the importance of these differences is undermined by our observation that the protein complements in all the parasites were qualitatively similar, regardless of RNAi-susceptibility. Clearly, differences in the RNAi pathway of parasitic nematodes do not explain the variations in susceptibility to experimental RNAi.
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Research Support, Non-U.S. Gov't |
14 |
100 |
6
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Wilson RP, Börger L, Holton MD, Scantlebury DM, Gómez-Laich A, Quintana F, Rosell F, Graf PM, Williams H, Gunner R, Hopkins L, Marks N, Geraldi NR, Duarte CM, Scott R, Strano MS, Robotka H, Eizaguirre C, Fahlman A, Shepard ELC. Estimates for energy expenditure in free-living animals using acceleration proxies: A reappraisal. J Anim Ecol 2019; 89:161-172. [PMID: 31173339 DOI: 10.1111/1365-2656.13040] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 04/10/2019] [Indexed: 11/30/2022]
Abstract
It is fundamentally important for many animal ecologists to quantify the costs of animal activities, although it is not straightforward to do so. The recording of triaxial acceleration by animal-attached devices has been proposed as a way forward for this, with the specific suggestion that dynamic body acceleration (DBA) be used as a proxy for movement-based power. Dynamic body acceleration has now been validated frequently, both in the laboratory and in the field, although the literature still shows that some aspects of DBA theory and practice are misunderstood. Here, we examine the theory behind DBA and employ modelling approaches to assess factors that affect the link between DBA and energy expenditure, from the deployment of the tag, through to the calibration of DBA with energy use in laboratory and field settings. Using data from a range of species and movement modes, we illustrate that vectorial and additive DBA metrics are proportional to each other. Either can be used as a proxy for energy and summed to estimate total energy expended over a given period, or divided by time to give a proxy for movement-related metabolic power. Nonetheless, we highlight how the ability of DBA to predict metabolic rate declines as the contribution of non-movement-related factors, such as heat production, increases. Overall, DBA seems to be a substantive proxy for movement-based power but consideration of other movement-related metrics, such as the static body acceleration and the rate of change of body pitch and roll, may enable researchers to refine movement-based metabolic costs, particularly in animals where movement is not characterized by marked changes in body acceleration.
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Research Support, Non-U.S. Gov't |
6 |
99 |
7
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Cook EH, Fletcher KE, Wainwright M, Marks N, Yan SY, Leventhal BL. Primary structure of the human platelet serotonin 5-HT2A receptor: identify with frontal cortex serotonin 5-HT2A receptor. J Neurochem 1994; 63:465-9. [PMID: 8035173 DOI: 10.1046/j.1471-4159.1994.63020465.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Previous radioligand binding studies have demonstrated human platelet serotonin2A (5-HT2A) receptor binding sites. Pharmacological similarities between platelet and frontal cortex 5-HT2A receptor binding parameters have been demonstrated. However, it is not clear whether the platelet 5-HT2A receptor primary structure is identical to that of the brain receptor. Three overlapping cDNAs were obtained to span completely the coding region of the 5-HT2A receptor. These clones were sequenced with external and internal primers. The nucleotide sequence of human platelet 5-HT2A cDNA was identical to that reported for the human frontal cortex 5-HT2A receptor, except for nucleotide 102 (T-->C), which has been reported to represent a normal DNA polymorphism that does not alter the amino acid sequence. This finding may have implications in the study of neuropsychiatric disorders for which altered platelet 5-HT2A receptor binding has been demonstrated.
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Comparative Study |
31 |
98 |
8
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Abstract
Blood flow to the inner ear was studied with a laser Doppler system in the acute guinea pig. Flow was measured through the lateral wall of the basal turn. Changes in simultaneous measures of cochlear and skin flow with rebreathing, epinephrine, phentolamine and terminal bleeding were studied. Cochlear blood flow followed skin blood flow in most cases; where it did not, the change was in an expected direction. The laser Doppler flowmeter appears to provide a direct, dynamic and linear measure of inner ear blood flow.
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42 |
93 |
9
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Abstract
In view of a large and growing literature, this overview emphasizes recent advances in neuronal caspases and their role in cell death. To provide historical perspective, morphology and methods are surveyed with emphasis on early studies on interleukin converting enzyme (ICE) as a prototype for identifying zymogen subunits. The unexpected homology of ICE (caspase-1) to Caenorhabditis elegans death gene CED-3 provided early clues linking caspases to programmed cell death, and led later to discovery of bcl-2 proteins (CED-9 homologs) and 'apoptosis associated factors' (Apafs). Availability of substrates, inhibitors, and cDNAs led to identification of up to 16 caspases as a new superfamily of unique cysteine proteinases targeting Asp groups. Those acting as putative death effectors dismantle neurons by catabolism of proteins essential for survival. Caspases degrade amyloid precursor protein (APP), presenilins (PS1, PS2), tau, and huntingtin, raising questions on their role in neurodegeneration. Brain contains 'inhibitors of apoptosis proteins' (IAPs) survivin and NAIP associated also with some neuronal disorders. Apoptotic stress in neurons initiates a chain of events leading to activation of distal caspases by pathways that remain to be fully mapped. Neuronal caspases play multiple roles for initiation and execution of cell death, for morphogenesis, and in non-mitotic neurons for homeostasis. Recent studies focus on cytochrome c as pivotal in mediating conversion of procaspase-9 as a major initiator for apoptosis. Identifying signaling pathways and related events paves the way to design useful therapeutic remedies to prevent neuronal loss in disease or aging.
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Review |
26 |
87 |
10
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Shechter M, Hod H, Marks N, Behar S, Kaplinsky E, Rabinowitz B. Beneficial effect of magnesium sulfate in acute myocardial infarction. Am J Cardiol 1990; 66:271-4. [PMID: 2195862 DOI: 10.1016/0002-9149(90)90834-n] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The effects of magnesium on the incidence of arrhythmias and on mortality were evaluated in 103 patients with documented acute myocardial infarction (AMI) in a randomized, double-blind, placebo-controlled study. Fifty patients received a magnesium infusion for 48 hours and 53 received only the vehicle (isotonic glucose) as placebo. The baseline characteristics of the population were similar in the 2 groups. Tachyarrhythmias requiring drug therapy were recorded in 32% of the patients in the magnesium group and in 45% of the placebo group. Conduction disturbances were found in 23% of the placebo group as compared to 14% in the magnesium group. The intrahospital mortality was 2% (1 patient) in the magnesium group, compared to 17% (9 patients) in the placebo group (p less than 0.01). No adverse effects were observed during and after the magnesium infusion. These data support a possible protective role of magnesium in patients with AMI.
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Clinical Trial |
35 |
81 |
11
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Benuck M, Marks N. Co-identity of brain angiotensin converting enzyme with a membrane bound dipeptidyl carboxypeptidase inactivating Met - enkephalin. Biochem Biophys Res Commun 1979; 88:215-21. [PMID: 222284 DOI: 10.1016/0006-291x(79)91718-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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46 |
80 |
12
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Benuck M, Marks N. Enzymatic inactivation of substance P by a partially purified enzyme from rat brain. Biochem Biophys Res Commun 1975; 65:153-60. [PMID: 1147979 DOI: 10.1016/s0006-291x(75)80073-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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50 |
80 |
13
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57 |
80 |
14
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McVeigh P, Leech S, Mair GR, Marks NJ, Geary TG, Maule AG. Analysis of FMRFamide-like peptide (FLP) diversity in phylum Nematoda. Int J Parasitol 2006; 35:1043-60. [PMID: 16076468 DOI: 10.1016/j.ijpara.2005.05.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 05/27/2005] [Accepted: 05/27/2005] [Indexed: 11/18/2022]
Abstract
This study reports a series of systematic BLAST searches of nematode ESTs on the Genbank database, using search strings derived from known nematode FLPs (those encoded by Caenorhabditis elegans flp genes as well as those isolated from other nematodes including Ascaris suum), as well as query sequences representative of theoretical FLPs. Over 1000 putative FLP-encoding ESTs were identified from multiple nematode species. A total of 969 ESTs representing sequelogs of the 23 known C. elegans flp genes were identified in 32 species, from clades I, III, IV and V. Numerical analysis of EST numbers suggests that flp-1, flp-11 and flp-14 are amongst the most highly expressed flp genes. Speculative BLAST searches were performed using theoretical FLP C-termini as queries, in an attempt to identify putative novel FLP sequences in the EST database. These searches yielded eight multi-species sequelogs encoding FLPs with novel signatures that are believed to identify distinct flp genes. These novel genes encode 25 distinct previously unidentified FLPs, and raise the current total of known nematode flp genes to 31. Additionally, software-based analyses of the presence of signal peptides were performed, with signal peptides being identified on at least one member of each group of flp ESTs, further confirming their status as secreted peptides. The data reveal that nematode FLPs encompass the most complex neuropeptide family known within the metazoa. Moreover, individual FLPs and FLP motifs are highly conserved across the nematodes with little evidence for inter-clade or inter-lifestyle variation, supporting their fundamental role in free-living and parasitic species.
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Journal Article |
19 |
78 |
15
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Marks N, Stern F. Enzymatic mechanisms for the inactivation of luteinizing hormone-releasing hormone (LH-RH). Biochem Biophys Res Commun 1974; 61:1458-63. [PMID: 4616701 DOI: 10.1016/s0006-291x(74)80447-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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51 |
78 |
16
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Einstein ER, Csejtey J, Marks N. Degradation of encephalitogen by purified brain acid proteinase. FEBS Lett 1968; 1:191-195. [PMID: 11945291 DOI: 10.1016/0014-5793(68)80057-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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57 |
77 |
17
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Scantlebury DM, Mills MGL, Wilson RP, Wilson JW, Mills MEJ, Durant SM, Bennett NC, Bradford P, Marks NJ, Speakman JR. Flexible energetics of cheetah hunting strategies provide resistance against kleptoparasitism. Science 2014; 346:79-81. [DOI: 10.1126/science.1256424] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Population viability is driven by individual survival, which in turn depends on individuals balancing energy budgets. As carnivores may function close to maximum sustained power outputs, decreased food availability or increased activity may render some populations energetically vulnerable. Prey theft may compromise energetic budgets of mesopredators, such as cheetahs and wild dogs, which are susceptible to competition from larger carnivores. We show that daily energy expenditure (DEE) of cheetahs was similar to size-based predictions and positively related to distance traveled. Theft at 25% only requires cheetahs to hunt for an extra 1.1 hour per day, increasing DEE by just 12%. Therefore, not all mesopredators are energetically constrained by direct competition. Other factors that increase DEE, such as those that increase travel, may be more important for population viability.
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11 |
73 |
18
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Cattral MS, Molinari M, Vollmer CM, McGilvray I, Wei A, Walsh M, Adcock L, Marks N, Lilly L, Girgrah N, Levy G, Greig PD, Grant DR. Living-donor right hepatectomy with or without inclusion of middle hepatic vein: comparison of morbidity and outcome in 56 patients. Am J Transplant 2004; 4:751-7. [PMID: 15084170 DOI: 10.1111/j.1600-6143.2004.00405.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Venous congestion of segments V and VIII is observed frequently in living-donor right lobe liver transplants without middle hepatic vein (MHV) drainage, and can be a cause of graft dysfunction and failure. Inclusion of the MHV with the graft is controversial, however, because of the perceived potential for increased donor morbidity. We compared the outcome of living liver donors in whom the MHV was either left intact in the donor (group 1; n = 28) or was removed with the graft (group 2; n = 28). All prospective donors completed an extensive multidisciplinary evaluation to determine suitability for surgery and to ensure that the MHV could be removed safely without compromising venous outflow from the remaining liver. Patient demographics including age, weight, body-mass index, and liver volumetry as determined by computerized tomography were similar in both groups. Operative time in group 2 was significantly shorter than in group 1. There was no difference in estimated blood loss, transfusion requirements, peak serum liver tests, time interval from surgery to complete normalization of liver tests, complications, and length of hospitalization. We conclude that including the MHV with living-donor right lobe grafts can be performed safely in most donors.
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Comparative Study |
21 |
73 |
19
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Maule AG, Mousley A, Marks NJ, Day TA, Thompson DP, Geary TG, Halton DW. Neuropeptide signaling systems - potential drug targets for parasite and pest control. Curr Top Med Chem 2002; 2:733-58. [PMID: 12052188 DOI: 10.2174/1568026023393697] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Current problems of drug resistance in parasites and pests demand the identification of new targets and their exploitation through novel drug design and development programs. Neuropeptide signaling systems in helminths (nematodes and platyhelminths = worms) and arthropods are well developed and complex, play a crucial role in many aspects of their biology, and appear to have significant potential as targets for novel drugs. The best-known neuropeptide family in invertebrates is the FMRFamide-related peptides (FaRPs). Amongst many roles, FaRPs potently influence motor function. The genome sequencing projects of Drosophila melanogaster and Caenorhabditis elegans have revealed unexpected complexity within the FaRPergic systems of arthropods and nematodes, although available evidence for platyhelminths indicates structural and functional simplicity. Regardless of these differences, FaRPs potently modulate motor function in arthropods, nematodes and platyhelminths and there appears to be at least some commonality in the FaRPergic signaling systems therein. Moreover, there is now increasing evidence of cross-phyla activity for individual FaRPs, providing clear signals of opportunities for target selection and the identification and development of broad-spectrum drugs.
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Review |
23 |
72 |
20
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Feld JJ, Cypel M, Kumar D, Dahari H, Pinto Ribeiro RV, Marks N, Kamkar N, Bahinskaya I, Onofrio FQ, Zahoor MA, Cerrochi O, Tinckam K, Kim SJ, Schiff J, Reichman TW, McDonald M, Alba C, Waddell TK, Sapisochin G, Selzner M, Keshavjee S, Janssen HLA, Hansen BE, Singer LG, Humar A. Short-course, direct-acting antivirals and ezetimibe to prevent HCV infection in recipients of organs from HCV-infected donors: a phase 3, single-centre, open-label study. Lancet Gastroenterol Hepatol 2020; 5:649-657. [PMID: 32389183 PMCID: PMC7391837 DOI: 10.1016/s2468-1253(20)30081-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/28/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND An increasing percentage of potential organ donors are infected with hepatitis C virus (HCV). After transplantation from an infected donor, establishment of HCV infection in uninfected recipients is near-universal, with the requirement for post-transplant antiviral treatment. The aim of this study was to determine if antiviral drugs combined with an HCV entry blocker given before and for 7 days after transplant would be safe and reduce the likelihood of HCV infection in recipients of organs from HCV-infected donors. METHODS HCV-uninfected organ recipients without pre-existing liver disease were treated with ezetimibe (10 mg; an HCV entry inhibitor) and glecaprevir-pibrentasvir (300 mg/120 mg) before and after transplantation from HCV-infected donors aged younger than 70 years without co-infection with HIV, hepatitis B virus, or human T-cell leukaemia virus 1 or 2. Recipients received a single dose 6-12 h before transplant and once a day for 7 days after surgery (eight doses in total). HCV RNA was assessed once a day for 14 days and then once a week until 12 weeks post-transplant. The primary endpoint was prevention of chronic HCV infection, as evidenced by undetectable serum HCV RNA at 12 weeks after transplant, and assessed in the intention-to-treat population. Safety monitoring was according to routine post-transplant practice. 12-week data are reported for the first 30 patients. The trial is registered on ClinicalTrials.gov, NCT04017338. The trial is closed to recruitment but follow-up is ongoing. FINDINGS 30 patients (23 men and seven women; median age 61 years (IQR 48-66) received transplants (13 lung, ten kidney, six heart, and one kidney-pancreas) from 18 HCV-infected donors. The median donor viral load was 5·11 log10IU/mL (IQR 4·55-5·63) and at least three HCV genotypes were represented (nine [50%] donors with genotype 1, two [11%] with genotype 2, five [28%] with genotype 3, and two [11%] with unknown genotype). All 30 (100%) transplant recipients met the primary endpoint of undetectable HCV RNA at 12 weeks post-transplant, and were HCV RNA-negative at last follow-up (median 36 weeks post-transplant [IQR 25-47]). Low-level viraemia was transiently detectable in 21 (67%) of 30 recipients in the early post-transplant period but not after day 14. Treatment was well tolerated with no dose reductions or treatment discontinuations; 32 serious adverse events occurred in 20 (67%) recipients, with one grade 3 elevation in alanine aminotransferase (ALT) possibly related to treatment. Non-serious transient elevations in ALT and creatine kinase during the study dosing period resolved with treatment completion. Among the serious adverse events were two recipient deaths due to causes unrelated to study drug treatment (sepsis at 49 days and subarachnoid haemorrhage at 109 days post-transplant), with neither patient ever being viraemic for HCV. INTERPRETATION Ezetimibe combined with glecaprevir-pibrentasvir given one dose before and for 7 days after transplant prevented the establishment of chronic HCV infection in recipients of different organs from HCV-infected donors. This study shows that an ultra-short course of direct-acting antivirals and ezetimibe can prevent the establishment of chronic HCV infection in the recipient, alleviating many of the concerns with transplanting organs from HCV-infected donors. FUNDING Canadian Institutes of Health Research; the Organ Transplant Program, University Health Network.
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Clinical Trial, Phase III |
5 |
72 |
21
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Marks N, Stern F, Lajtha A. Changes in proteolytic enzymes and proteins during maturation of the brain. Brain Res 1975; 86:307-22. [PMID: 1116000 DOI: 10.1016/0006-8993(75)90705-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
(1) Changes during development in the levels of proteinases and peptidases were measured in brain homogenates. At all ages di- and tripeptidase levels were 7-15-fold higher than proteinase activity. (2) Cathepsin A and D and neutral proteinase activity first decreased (during the 5 days before birth) and then increased (primarily during the first 10 days after birth) in development. The total enzyme content per unit weight of brain did not change greatly after 10 days, although specific activity fell owing to an increase in protein in older animals. (3) The developmental pattern of activities or peptidases measured with Leu-Gly and Leu-Gly-Gly and of arylamidases measured with Arg- and Arg-Arg-beta-naphthylamides was similar to that of proteinases. Total and specific activities increased rapidly after birth; then total activity did not change and specific activity decreased. (4) The proteinase content of tissue fractions (nuclear and lysosomal-mitochondrial) similarly reached a maximal peak in the rapid growth phase of the brain. (5) The decrease of hydrolytic activity after 10 days of age seems to parallel a decrease in the rates of protein breakdown in vivo, showing parallel behavior with decreasing protein turnover. In contrast, during the first 10 days of life protein turnover and calculated rate of protein breakdown in vivo decrease while the level of hydrolytic enzymes increases.
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50 |
70 |
22
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Maule AG, Geary TG, Bowman JW, Marks NJ, Blair KL, Halton DW, Shaw C, Thompson DP. Inhibitory effects of nematode FMRFamide-related peptides (FaRPs) on muscle strips from Ascaris suum. INVERTEBRATE NEUROSCIENCE : IN 1995; 1:255-65. [PMID: 9372147 DOI: 10.1007/bf02211027] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A large number of FMRFamide-related peptides (FaRPs) are found in nematodes, and some of these are known to influence tension and contractility of neuromuscular strips isolated from Ascaris suum body wall. Relaxation of these strips has been noted with five nematode FaRPs. The inhibitory actions of SDPNFLRFamide (PF1) and SADPNFLRFamide (PF2) appear to be mediated by nitric oxide, as previously demonstrated with inhibitors of nitric oxide synthase (NOS). This present study showed that the effects of PF1 were also depended on external Ca++ and were reduced by the Ca(++)-channel blocker verapamil, observations consistent with the finding that nematode NOS is Ca(++)-dependent. KSAYMRFamide (PF3), KNIRFamide (PF4) and KNAFIRFamide (an alanine substituted analog of KNEFIRFamide, AF1, termed A3AF1) also relaxed A. suum muscle strips, but these responses were not affected by NOS inhibitors. PF3 inhibited the activity of strips prepared from the dorsal side of the worm, but contracted ventral strips. Both effects were dependent on the presence of ventral/dorsal nerve cords (unlike PF1/PF2) and were attenuated in medium which contained high K+ or low Ca++. PF4-induced muscle relaxation and hyperpolarization were independent of nerve cords, but were reversed in Cl-free medium, unlike PF1 or PF3. The PF4 effect physiologically desensitized muscle strips to subsequent treatment with PF4 and/or GABA. However, PF4 and GABA were not synergistic in this preparation. The effects of GABA, but not PF4, were reduced in muscle strips treated with the GABA antagonist, NCS 281-93. Following PF4 (or GABA) relaxation, subsequent treatment with higher doses of PF4 caused muscle strip contraction. A3AF1 was found to relax muscle strips and hyperpolarize muscle cells independently of the ventral and dorsal nerve cords, K+, Ca++, and Cl-, and mimicked the inhibitory phase associated with the exposure of these strips to AF1. On the basis of anatomical and ionic dependence, these data have delineated at least four distinct inhibitory activities attributable to nematode FaRPs. Clearly, a remarkably complex set of inhibitory mechanisms operate in the nematode neuromuscular system.
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McVeigh P, Mair GR, Atkinson L, Ladurner P, Zamanian M, Novozhilova E, Marks NJ, Day TA, Maule AG. Discovery of multiple neuropeptide families in the phylum Platyhelminthes. Int J Parasitol 2009; 39:1243-52. [PMID: 19361512 DOI: 10.1016/j.ijpara.2009.03.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 02/20/2009] [Accepted: 03/11/2009] [Indexed: 10/20/2022]
Abstract
Available evidence shows that short amidated neuropeptides are widespread and have important functions within the nervous systems of all flatworms (phylum Platyhelminthes) examined, and could therefore represent a starting point for new lead drug compounds with which to combat parasitic helminth infections. However, only a handful of these peptides have been characterised, the rigorous exploration of the flatworm peptide signalling repertoire having been hindered by the dearth of flatworm genomic data. Through searches of both expressed sequence tags and genomic resources using the basic local alignment search tool (BLAST), we describe 96 neuropeptides on 60 precursors from 10 flatworm species. Most of these (51 predicted peptides on 14 precursors) are novel and are apparently restricted to flatworms; the remainder comprise nine recognised peptide families including FMRFamide-like (FLPs), neuropeptide F (NPF)-like, myomodulin-like, buccalin-like and neuropeptide FF (NPFF)-like peptides; notably, the latter have only previously been reported in vertebrates. Selected peptides were localised immunocytochemically to the Schistosoma mansoni nervous system. We also describe several novel flatworm NPFs with structural features characteristic of the vertebrate neuropeptide Y (NPY) superfamily, previously unreported characteristics which support the common ancestry of flatworm NPFs with the NPY-superfamily. Our dataset provides a springboard for investigation of the functional biology and therapeutic potential of neuropeptides in flatworms, simultaneously launching flatworm neurobiology into the post-genomic era.
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Benuck M, Marks N, Hashim GA. Metabolic instability of myelin proteins. Breakdown of basic protein induced by brain cathepsin D. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 52:615-21. [PMID: 70349 DOI: 10.1111/j.1432-1033.1975.tb04033.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Abstract
Caspase-3 activity increased dramatically in cytosolic extracts of rat cerebellar granule cells exposed to apoptotic conditions (basal medium Eagle (BME) containing 5 mM K+ without serum) when assayed with Ac-DEVD-amc, but not with Ac-YVAD-afc, a preferred substrate for caspase-1. This provided a basis to examine relationships between enzyme activity and cell viability for purposes of selecting an optimal time for comparing neuroprotective agents or strategies. Exposure of neurons to an apoptotic medium containing 5 mM K+ in absence of serum led to a rapid 5- to 10-fold increase in caspase-3 within 2-4 hr but without significant cell loss, or morphological alterations. Exposure to apoptotic medium followed by replacement with maintenance medium containing 25 mM K+ and serum led to a rapid fall in caspase-3 and prevention of cell death. This strategy was not effective after 13 hr exposure despite a large fall in enzyme activity. These temporal changes infer systems for rapid enzyme turnover and/or activation of cytoplasmic components linked to later DNA degradation. The effects of cycloheximide point to requirements for protein synthesis, and those of Glu exclude a caspase-3 dependent pathway for necrotic cell damage. Brief treatment with 10 microM LIGA20, an anti-necrotic agent, also attenuated cell loss and caspase-3 activity, indicating a broad spectrum of neuroprotection. Rapid and long-lasting effects, together with its biophysical properties, suggest that this semisynthetic ganglioside acted upstream at or near a membrane site. As such, gangliosides provide useful agents to further probe pathways relevant to neuronal death in culture.
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