Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 26
Filter
2.
Neurochem Res ; 48(10): 3027-3041, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37289348

ABSTRACT

N-methyl-D-aspartate (NMDA) receptor hypofunctionality is a well-studied hypothesis for schizophrenia pathophysiology, and daily dosing of the NMDA receptor co-agonist, D-serine, in clinical trials has shown positive effects in patients. Therefore, inhibition of D-amino acid oxidase (DAAO) has the potential to be a new therapeutic approach for the treatment of schizophrenia. TAK-831 (luvadaxistat), a novel, highly potent inhibitor of DAAO, significantly increases D-serine levels in the rodent brain, plasma, and cerebrospinal fluid. This study shows luvadaxistat to be efficacious in animal tests of cognition and in a translational animal model for cognitive impairment in schizophrenia. This is demonstrated when luvadaxistat is dosed alone and in conjunction with a typical antipsychotic. When dosed chronically, there is a suggestion of change in synaptic plasticity as seen by a leftward shift in the maximum efficacious dose in several studies. This is suggestive of enhanced activation of NMDA receptors in the brain and confirmed by modulation of long-term potentiation after chronic dosing. DAAO is highly expressed in the cerebellum, an area of increasing interest for schizophrenia, and luvadaxistat was shown to be efficacious in a cerebellar-dependent associative learning task. While luvadaxistat ameliorated the deficit seen in sociability in two different negative symptom tests of social interaction, it failed to show an effect in endpoints of negative symptoms in clinical trials. These results suggest that luvadaxistat potentially could be used to improve cognitive impairment in patients with schizophrenia, which is not well addressed with current antipsychotic medications.


Subject(s)
Antipsychotic Agents , Schizophrenia , Animals , Oxidoreductases , Rodentia , Schizophrenia/drug therapy , Antipsychotic Agents/pharmacology , Antipsychotic Agents/therapeutic use , Enzyme Inhibitors/pharmacology , Cognition , Serine/pharmacology , Amino Acids , Receptors, N-Methyl-D-Aspartate
3.
PLoS One ; 17(11): e0275288, 2022.
Article in English | MEDLINE | ID: mdl-36355835

ABSTRACT

Early analyses revealed that dark web marketplaces (DWMs) started offering COVID-19 related products (e.g., masks and COVID-19 tests) as soon as the COVID-19 pandemic started, when these goods were in shortage in the traditional economy. Here, we broaden the scope and depth of previous investigations by considering how DWMs responded to an ongoing pandemic after the initial shock. Our dataset contains listings from 194 DWMs collected until July 2021. We start by focusing on vaccines. We find 248 listings offering approved vaccines, like Pfizer/BioNTech and AstraZeneca, as well as vendors offering fabricated proofs of vaccination and COVID-19 passports. Then, we consider COVID-19 related products. We show that, as the regular economy has become able to satisfy the demand of these goods, DWMs have decreased their offer. Next, we analyse the profile of vendors of COVID-19 related products and vaccines. We find that most of them are specialized in a single type of listings and are willing to ship worldwide. Finally, we consider a broader set of listings mentioning COVID-19, in order to assess the general impact of the pandemic on the broader activity of DWMs. Among 10,330 such listings, we show that recreational drugs are the most affected among traditional DWMs product, with COVID-19 mentions steadily increasing since March 2020. We anticipate that our results will be of interest to researchers, practitioners, and law enforcement agencies focused on the study and safeguard of public health.


Subject(s)
COVID-19 , Vaccines , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Pandemics/prevention & control , Vaccination , Commerce
4.
BMC Public Health ; 22(1): 1151, 2022 06 09.
Article in English | MEDLINE | ID: mdl-35681199

ABSTRACT

BACKGROUND: Influenza surveillance systems vary widely between countries and there is no framework to evaluate national surveillance systems in terms of data generation and dissemination. This study aimed to develop and test a comparative framework for European influenza surveillance. METHODS: Surveillance systems were evaluated qualitatively in five European countries (France, Germany, Italy, Spain, and the United Kingdom) by a panel of influenza experts and researchers from each country. Seven surveillance sub-systems were defined: non-medically attended community surveillance, virological surveillance, community surveillance, outbreak surveillance, primary care surveillance, hospital surveillance, mortality surveillance). These covered a total of 19 comparable outcomes of increasing severity, ranging from non-medically attended cases to deaths, which were evaluated using 5 comparison criteria based on WHO guidance (granularity, timing, representativeness, sampling strategy, communication) to produce a framework to compare the five countries. RESULTS: France and the United Kingdom showed the widest range of surveillance sub-systems, particularly for hospital surveillance, followed by Germany, Spain, and Italy. In all countries, virological, primary care and hospital surveillance were well developed, but non-medically attended events, influenza cases in the community, outbreaks in closed settings and mortality estimates were not consistently reported or published. The framework also allowed the comparison of variations in data granularity, timing, representativeness, sampling strategy, and communication between countries. For data granularity, breakdown per risk condition were available in France and Spain, but not in the United Kingdom, Germany and Italy. For data communication, there were disparities in the timeliness and accessibility of surveillance data. CONCLUSIONS: This new framework can be used to compare influenza surveillance systems qualitatively between countries to allow the identification of structural differences as well as to evaluate adherence to WHO guidance. The framework may be adapted for other infectious respiratory diseases.


Subject(s)
Influenza, Human , Europe/epidemiology , France/epidemiology , Humans , Influenza, Human/epidemiology , United Kingdom/epidemiology , World Health Organization
5.
EPJ Data Sci ; 10(1): 6, 2021.
Article in English | MEDLINE | ID: mdl-33500876

ABSTRACT

The COVID-19 pandemic has reshaped the demand for goods and services worldwide. The combination of a public health emergency, economic distress, and misinformation-driven panic have pushed customers and vendors towards the shadow economy. In particular, dark web marketplaces (DWMs), commercial websites accessible via free software, have gained significant popularity. Here, we analyse 851,199 listings extracted from 30 DWMs between January 1, 2020 and November 16, 2020. We identify 788 listings directly related to COVID-19 products and monitor the temporal evolution of product categories including Personal Protective Equipment (PPE), medicines (e.g., hydroxyclorochine), and medical frauds. Finally, we compare trends in their temporal evolution with variations in public attention, as measured by Twitter posts and Wikipedia page visits. We reveal how the online shadow economy has evolved during the COVID-19 pandemic and highlight the importance of a continuous monitoring of DWMs, especially now that real vaccines are available and in short supply. We anticipate our analysis will be of interest both to researchers and public agencies focused on the protection of public health.

6.
Am J Lifestyle Med ; 14(2): 169-186, 2020.
Article in English | MEDLINE | ID: mdl-32231483

ABSTRACT

Precision medicine has captured the imagination of the medical community with visions of therapies precisely targeted to the specific individual's genetic, biological, social, and environmental profile. However, in practice it has become synonymous with genomic medicine. As such its successes have been limited, with poor predictive or clinical value for the majority of people. It adds little to lifestyle medicine, other than in establishing why a healthy lifestyle is effective in combatting chronic disease. The challenge of lifestyle medicine remains getting people to actually adopt, sustain, and naturalize a healthy lifestyle, and this will require an approach that treats the patient as a person with individual needs and providing them with suitable types of support. The future of lifestyle medicine is holistic and person-centered rather than technological.

7.
Investig Clin Urol ; 59(2): 126-132, 2018 03.
Article in English | MEDLINE | ID: mdl-29520389

ABSTRACT

Purpose: To assess the utility of the Manufacturer And User Facility Device Experience (MAUDE) database in objectively capturing adverse events for transvaginal mesh in the United States. Materials and Methods: We reviewed 1,103 individual medical device reports submitted to the MAUDE database that inspired the United States (US) Food and Drug Administration's 2008 Public Health Notification. Entries were compiled into a categorical database that reported manufacturer, brand, reporter type, report source, and type of adverse event. Results: There were numerous examples of missing, duplicated, and non-standardized entries. Analysis revealed 64 reports with duplicated information, and six reports representing multiple patients. Forty-seven percent of medical device reports did not identify a reporter source. At least 28% of reported devices are no longer on the US market. There was wide variability in the quality and completeness of submitted reports and true adverse event rates could not be accurately calculated because the number of total cases was unknown. Conclusions: The MAUDE database was limited in its ability to collect, quantify, and standardize real-life adverse events related to transvaginal mesh. While it functions to collect information related to isolated adverse events, systematic limitations of the MAUDE database, that no doubt extend to other medical devices, necessitate the development of new reporting systems. Alternatives are under development, which may allow regulators to more accurately scrutinize the safety profiles of specific medical devices.


Subject(s)
Equipment Safety , Gynecologic Surgical Procedures/instrumentation , Surgical Mesh , Data Accuracy , Data Collection/statistics & numerical data , Databases, Factual , Equipment Safety/methods , Equipment Safety/statistics & numerical data , Female , Gynecologic Surgical Procedures/adverse effects , Gynecologic Surgical Procedures/methods , Humans , Pelvic Organ Prolapse/surgery , Surgical Mesh/adverse effects , Surgical Mesh/standards , United States , United States Food and Drug Administration , Urinary Incontinence, Stress/surgery
8.
BMC Urol ; 14: 10, 2014 Jan 25.
Article in English | MEDLINE | ID: mdl-24461081

ABSTRACT

BACKGROUND: Prospective studies suggested an association between pioglitazone (Actos) use and the development of bladder cancer. Cancer pathology among pioglitazone users has not been characterized. We chose to compare the surgical pathology among diabetic users and non-users, as well as non-diabetic patients who underwent radical cystectomy for bladder cancer. METHODS: Our single-center, prospectively-maintained bladder cancer database was reviewed. Patient demographics, surgical pathology, and outcomes were evaluated. Information regarding diabetic history and use of pioglitazone was determined from chart analysis and patient interview. RESULTS: From April 2005 to October 2011, 204 patients undergoing radical cystectomy were identified. Of these, 33 (16.2%) were diabetic and 171 (83.8%) had no history of diabetes. Among diabetic patients, 9 (27.3%) had a history of pioglitazone use. Median duration of therapy was 14 (6-120) months. Pathology in non-diabetic patients was T1 in 17 (9.9%), T2 in 38 (22.2%), T3 in 44 (25.7%), and T4 in 31 (18.1%). Pathology among diabetic non-users was T1 in 1 (4.2%), T2 in 7 (29.2%), T3 in 7 (29.2%), and T4 in 4 (16.7%). Pathologic stage among diabetic users was T1 in 1 (11.1%), T2 in 3 (33.3%), T3 in 3 (33.3%), and T4 in 1 (11.1%). Lymph node involvement in non-diabetics, diabetic non-users, and diabetic users was 25.7%, 33.3%, and 33.3%, respectively. Cancer-specific death was seen in 60.3% of non-diabetics, 58.3% of diabetic non-users, and 75% of diabetic users. CONCLUSIONS: Diabetics have similar stage distribution regardless of pioglitazone use. Lymph node metastases rates and cancer specific death were similar across all groups. Additional studies will serve to better characterize this relationship.


Subject(s)
Cystectomy , Diabetes Mellitus/drug therapy , Thiazolidinediones/adverse effects , Thiazolidinediones/therapeutic use , Urinary Bladder Neoplasms/chemically induced , Urinary Bladder Neoplasms/pathology , Aged , Female , Humans , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/therapeutic use , Male , Pioglitazone , Retrospective Studies , Risk Assessment , Treatment Outcome , Urinary Bladder Neoplasms/surgery
9.
Eur J Hum Genet ; 21(1): 102-8, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22692064

ABSTRACT

A massive hexanucleotide repeat expansion mutation (HREM) in C9ORF72 has recently been linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we describe the frequency, origin and stability of this mutation in ALS+/-FTD from five European cohorts (total n=1347). Single-nucleotide polymorphisms defining the risk haplotype in linked kindreds were genotyped in cases (n=434) and controls (n=856). Haplotypes were analysed using PLINK and aged using DMLE+. In a London clinic cohort, the HREM was the most common mutation in familial ALS+/-FTD: C9ORF72 29/112 (26%), SOD1 27/112 (24%), TARDBP 1/112 (1%) and FUS 4/112 (4%) and detected in 13/216 (6%) of unselected sporadic ALS cases but was rare in controls (3/856, 0.3%). HREM prevalence was high for familial ALS+/-FTD throughout Europe: Belgium 19/22 (86%), Sweden 30/41 (73%), the Netherlands 10/27 (37%) and Italy 4/20 (20%). The HREM did not affect the age at onset or survival of ALS patients. Haplotype analysis identified a common founder in all 137 HREM carriers that arose around 6300 years ago. The haplotype from which the HREM arose is intrinsically unstable with an increased number of repeats (average 8, compared with 2 for controls, P<10(-8)). We conclude that the HREM has a single founder and is the most common mutation in familial and sporadic ALS in Europe.


Subject(s)
Amyotrophic Lateral Sclerosis/genetics , Founder Effect , Frontotemporal Dementia/genetics , Mutation , Proteins/genetics , Age of Onset , Amyotrophic Lateral Sclerosis/epidemiology , C9orf72 Protein , Cohort Studies , Europe/epidemiology , Frontotemporal Dementia/epidemiology , Gene Frequency , Genomic Instability , Haplotypes , Humans , Polymorphism, Single Nucleotide , Repetitive Sequences, Nucleic Acid
10.
ChemMedChem ; 6(11): 2070-80, 2011 Nov 04.
Article in English | MEDLINE | ID: mdl-21953839

ABSTRACT

AG-045572 (CMPD1, 1 a) is a nonpeptidic gonadotropin-releasing hormone (GnRH) antagonist that has been investigated for the treatment of sex hormone-related diseases. In the context of systematic studies on sila-substituted drugs, the silicon analogue disila-AG-045572 (1 b) and its derivative 2 were prepared in multi-step syntheses and characterized by elemental analyses (C, H, N), NMR spectroscopic studies (1H, 13C, 29Si), and single-crystal X-ray diffraction. The pharmacological properties of compounds 1 a, 1 b, and 2 were compared in terms of their in vitro potency at cloned human and rat GnRH receptors. Compounds 1 a and 2 were also examined in regard to their pharmacokinetics and in vivo efficacy in both castrated rat (luteinizing hormone (LH) suppression) and intact rat (testosterone suppression) models. The efficacy and pharmacokinetic profiles of 1 a and its silicon-containing analogue 2 appear similar, indicating that replacement of the 5,6,7,8-tetrahydronaphthalene ring system by the 1,3-disilaindane skeleton led to retention of efficacy. Therefore, the silicon compound 2 represents a novel drug prototype for the design of potent, orally available GnRH antagonists suitable for once-daily dosing.


Subject(s)
Furans/chemistry , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Hormone Antagonists/chemistry , Hormone Antagonists/pharmacology , Tetrahydronaphthalenes/chemistry , Animals , Crystallography, X-Ray , Drug Evaluation, Preclinical , Furans/pharmacology , Hormone Antagonists/pharmacokinetics , Humans , Luteinizing Hormone/antagonists & inhibitors , Magnetic Resonance Spectroscopy , Male , Molecular Structure , Orchiectomy , Rats, Wistar , Receptors, LHRH/genetics , Silicon/chemistry , Structure-Activity Relationship , Tetrahydronaphthalenes/pharmacology
11.
BMC Res Notes ; 3: 31, 2010 Feb 02.
Article in English | MEDLINE | ID: mdl-20181074

ABSTRACT

BACKGROUND: Several lines of evidence support a role for CCL2 (monocyte chemotactic protein-1) and its receptor CCR2 in the development of atherosclerosis. The aim of the present study was to determine the association of the CCR2 Val64Ile polymorphism with the development of coronary artery disease in the WOSCOPS study sample set. FINDINGS: A total of 443 cases and 1003 controls from the West of Scotland Coronary Prevention Study (WOSCOPS) were genotyped for the Val64Ile polymorphism in the CCR2 gene. Genotype frequencies were compared between cases and controls. The CCR2 Val64Ile polymorphism was found not to be associated with coronary events in this study population (odds ratio 1.15, 95% CI 0.82-1.61, p = 0.41). CONCLUSIONS: This case-control study does not support an association of the CCR2 Val64Ile polymorphism with coronary artery disease in the WOSCOPS sample set and does not confirm a possible protective role for CCR2 Val64Ile in the development of coronary artery disease.

12.
Carbohydr Res ; 342(14): 1998-2002, 2007 Oct 15.
Article in English | MEDLINE | ID: mdl-17572400

ABSTRACT

Monosaccharides are selectively converted to monobenzoates in a base-catalyzed reaction with benzoyl methyl phosphate (BzMP) and a lanthanum salt in water. Yields are reported in terms of formation of the ester, which competes with hydrolysis of BzMP, to give an estimate of the efficiency of the conversion of the sugar. Higher conversions can be achieved using excess reagent. Regioselectivity is influenced by the structure of the glycoside. For example, the reaction leads to different product distributions from alpha- and beta-anomers of the glycosides. The reaction combination provides a basis for efficient ester formation in specific geometric situations, providing a means of identification as well as modification.


Subject(s)
Benzoates/chemistry , Monosaccharides/chemistry , Chelating Agents , Lanthanum , Organophosphates , Water
13.
Chemistry ; 11(21): 6221-7, 2005 Oct 21.
Article in English | MEDLINE | ID: mdl-16075451

ABSTRACT

A new and improved method for the preparation of (PhPSe2)2 (Woollins reagent (WR), 1) is reported. Reaction of dichlorophenylphosphine with Na2Se, (prepared from the reaction of elemental selenium and sodium in liquid ammonia) gives WR with excellent purity, high yield and on a larger scale than was previously possible. Four novel phosphorus-selenium heterocycles, including a spirocyclic heterocycle exhibiting a four-membered P2SeC ring, were obtained from the reaction of WR with two reactive substrates (diphenylcyclopropenone and methyl phenylpropiolate). Useful selenocarbonyl and thiocarbonyl compounds were obtained from the reaction of both WR and Lawesson's reagent with diphenylcyclopropenone. All new compounds were characterised spectroscopically and three demonstrative X-ray structures are reported.

14.
J Peripher Nerv Syst ; 10(2): 174-80, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15958128

ABSTRACT

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired disorder of the peripheral nervous system with a probable auto-immune pathogenesis. The nature of the responsible autoantigens is unclear in most patients. We used the Western immunoblot technique to seek antibodies to peripheral nerve protein antigens. Sera from eight of 32 (25%) CIDP patients, 12 of 37 (32%) Guillain-Barré syndrome (GBS) patients, zero of 30 (0%) chronic idiopathic axonal polyneuropathy patients and two of 39 (5%) healthy control subjects contained anti-peripheral nerve protein antibodies. The frequency of such antibodies was significantly greater in both CIDP (p = 0.04) and GBS (p = 0.003) patients than in normal control subjects. For CIDP patients, there were non-significant trends for antibodies to be more common in females and in those who responded to treatment with either intravenous immunoglobulin or plasma exchange. The commonest antibodies were directed against a band at 28 kDa, resembling that labelled by a monoclonal antibody against myelin protein zero (P0). Six CIDP and seven GBS patients' sera reacted with this band. These results support the view that antibodies to myelin proteins, and especially P0, are present in the serum of some patients with CIDP and GBS.


Subject(s)
Antibodies/metabolism , Myelin Proteins/immunology , Peripheral Nerves/metabolism , Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/immunology , Adult , Aged , Antibodies/classification , Blotting, Western/methods , Enzyme-Linked Immunosorbent Assay/methods , Female , G(M1) Ganglioside/immunology , Guillain-Barre Syndrome/immunology , Humans , Male , Middle Aged , Molecular Weight , Time Factors
15.
Dalton Trans ; (12): 2188-94, 2005 Jun 21.
Article in English | MEDLINE | ID: mdl-15957062

ABSTRACT

Reaction of (PhPSe2)2(Woollins reagent) with NaOR (R = Me, Et, (i)Pr) gives the non-symmetric phosphonodiselenoato anions [Ph(RO)PSe2]- which can be complexed to a range of metals. The nickel complex Ni[Ph(MeO)PSe2]2 adopts a square-planar ML2 structure while the cadmium complex Cd[Ph(MeO)PSe2]2 displays a dimeric M2L4 structure. Two different lead complexes are observed, one consisting of PbL2 units joined by Pb...Se interactions to form distinct dimeric pairs. The other displays a novel dimeric structure built around a central four-membered Pb2Se2 ring. All new compounds have been characterised spectroscopically (31P, 1H, 13C NMR, IR, mass spectroscopy), by elemental analysis and five demonstrative X-ray structures are reported.

16.
Comp Funct Genomics ; 6(5-6): 268-76, 2005.
Article in English | MEDLINE | ID: mdl-18629217

ABSTRACT

The aryl hydrocarbon receptor nuclear translocator (ARNT) and cathepsin K (CTSK) genes lie in a tandem head-to-tail arrangement on human chromosome 1. The two genes are in extremely close proximity; the usual CTSK transcription start site is less than 1.4 kb downstream of the end of the longest reported ARNT transcript. By generating an RT-PCR product that overlaps both the 3' end of ARNT and the 5' end of CTSK, we show that ARNT transcripts may extend through the ARNT-CTSK intergenic region and progress into the CTSK gene. Furthermore, by using quantitative RT-PCR from several tissues to detect the ARNT expression signature in CTSK introns, we show that ARNT transcripts can read through into CTSK as far as CTSK intron 3, extending approximately 3.7 kb downstream of the end of the longest previously described ARNT mRNA. Given that ARNT and CTSK are expressed in an overlapping range of tissues, ARNT read-through may have a negative impact on CTSK transcript levels by interfering with CTSK expression. We also present evidence for novel CTSK transcripts following sequence analysis of CTSK-derived ESTs and RT-PCR products. These transcripts show alternate 5' splicing and or 5' extension and are sometimes initiated from a cryptic alternative promoter which is upstream of the known CTSK promoter and possibly in the 3' UTR of ARNT.

17.
Genetica ; 122(1): 47-9, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15619960

ABSTRACT

With the completion of the first draft of the human genome sequence, the next major challenge is assigning function to genes. One approach is genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes of interest and subsequent mapping and identification of the mutated genes in question. We (a consortium made up of GlaxoSmithKline, the MRC Mammalian Genetics Unit and Mouse Genome Centre, Harwell, Imperial College, London, and the Royal London Hospital) have used ENU mutagenesis in the mouse for the rapid generation of novel mutant phenotypes for use as animal models of human disease and for gene function assignment (Nolan et al., 2000). As of 2003, 35,000 mice have been produced to date in a genome-wide screen for dominant mutations and screened using a variety of screening protocols. Nearly 200 mutants have been confirmed as heritable and added to the mouse mutant catalogue and, overall, we can extrapolate that we have recovered over 700 mutants from the screening programme. For further information on the project and details of the data, see http://www.mgu.har.mrc.ac.uk/mutabase.


Subject(s)
Chromosome Mapping , Disease Models, Animal , Genome , Mice/genetics , Animals , Mutation , Phenotype
18.
Mamm Genome ; 15(8): 585-91, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15457338

ABSTRACT

N-ethyl-N-nitrosourea (ENU) introduces mutations throughout the mouse genome at relatively high efficiency. Successful high-throughput phenotype screens have been reported and alternative screens using sequence-based approaches have been proposed. For the purpose of generating an allelic series in selected genes by a sequence-based approach, we have constructed an archive of over 4000 DNA samples from individual F1 ENU-mutagenized mice paralleled by frozen sperm samples. Together with our previously reported archive, the total size now exceeds 6000 individuals. A gene-based screen of 27.4 Mbp of DNA, carried out using denaturing high-performance liquid chromatography (DHPLC), found a mutation rate of 1 in 1.01 Mbp of which 1 in 1.82 Mbp were potentially functional. Screening of whole or selected regions of genes on subsets of the archive has allowed us to identify 15 new alleles from 9 genes out of 15 tested. This is a powerful adjunct to conventional mutagenesis strategies and has the advantage of generating a variety of alleles with potentially different phenotypic outcomes that facilitate the investigation of gene function. It is now available to academic collaborators as a community resource.


Subject(s)
Alkylating Agents/pharmacology , Alleles , Ethylnitrosourea/pharmacology , Mutation , Animals , Chromatography, High Pressure Liquid , DNA Mutational Analysis , Mice
19.
Mol Pharmacol ; 66(4): 921-8, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15385642

ABSTRACT

Adenylyl cyclases (AC), a family of enzymes that catalyze the synthesis of cyclic AMP, are critical regulators of cellular functions. The activity of adenylyl cyclase is stimulated by a range of hormone receptors, primarily via interactions with G-proteins; however, recently we identified an alternate mechanism by which growth factors sensitize adenylyl cyclase activation. We suggested that this mechanism might involve a Raf kinase-mediated serine phosphorylation of adenylyl cyclase. However, the direct involvement of a specific form of Raf kinase is yet to be demonstrated. Furthermore, whether this mechanism is generalized to other isoforms of adenylyl cyclase is unknown. In human embryonic kidney 293 cells, we now demonstrate that in reconstitution studies, c-Raf kinase can mediate phosphorylation of AC VI. Furthermore, AC VI coimmunoprecipitates with c-Raf. Raf kinase-dependent regulation of adenylyl cyclase VI is dependent on the integrity of Ser750 in the fourth intracellular loop of the enzyme and Ser603/Ser608 in the C1b region of the molecule. To examine how generalized this effect is, we studied representative isoforms of the major subfamilies of adenylyl cyclase viz., AC I, AC II, and AC V. Raf kinase-dependent sensitization/ phosphorylation of adenylyl cyclases is common to AC VI, AC V, and AC II isoforms but not AC I. In aggregate, these studies indicate that Raf kinase associates with adenylyl cyclases. Furthermore, Raf kinase regulation of adenylyl cyclase is isoform-selective. These functional interactions (as well as the physical association) between adenylyl cyclases and Raf kinases suggest an important but previously unrecognized interaction between these two key regulatory enzymes.


Subject(s)
Adenylyl Cyclases/metabolism , Cyclic AMP/metabolism , Isoenzymes/metabolism , Proto-Oncogene Proteins c-raf/metabolism , Amino Acids/metabolism , Enzyme Activation , Humans , Phosphorylation , Tumor Cells, Cultured
20.
Dalton Trans ; (16): 2477-86, 2004 Aug 21.
Article in English | MEDLINE | ID: mdl-15303162

ABSTRACT

Reaction of An(S)PS(2)P(S)An with NaOR [R = Me, Et, (i)Pr] gives the non-symmetric phosphonodithioato anions [An(RO)PS(2)](-) which can be complexed to a range of metals. The group 10 metals (Ni, Pd and Pt) adopt square planar ML(2) complexes. The zinc and cadmium complexes adopt isostructural dimeric M(2)L(4) structures whilst mercury complexes adopt a subtly different dimeric motif. Two distinctly different lead complexes are reported, one consisting of PbL(2) units joined by Pb...S interactions to form distinct dimeric pairs, the other being a completely new structural motif for complexes of this type, PbL(2) units held together by covalently bonded bridging ligands to form an infinite polymeric chain structure. All new compounds have been characterised spectroscopically and nine demonstrative X-ray structures are reported.

SELECTION OF CITATIONS
SEARCH DETAIL