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1.
J Med Chem ; 65(12): 8208-8226, 2022 06 23.
Article in English | MEDLINE | ID: mdl-35647711

ABSTRACT

Peptide agonists of the glucagon-like peptide-1 receptor (GLP-1R) have revolutionized diabetes therapy, but their use has been limited because they require injection. Herein, we describe the discovery of the orally bioavailable, small-molecule, GLP-1R agonist PF-06882961 (danuglipron). A sensitized high-throughput screen was used to identify 5-fluoropyrimidine-based GLP-1R agonists that were optimized to promote endogenous GLP-1R signaling with nanomolar potency. Incorporation of a carboxylic acid moiety provided considerable GLP-1R potency gains with improved off-target pharmacology and reduced metabolic clearance, ultimately resulting in the identification of danuglipron. Danuglipron increased insulin levels in primates but not rodents, which was explained by receptor mutagensis studies and a cryogenic electron microscope structure that revealed a binding pocket requiring a primate-specific tryptophan 33 residue. Oral administration of danuglipron to healthy humans produced dose-proportional increases in systemic exposure (NCT03309241). This opens an opportunity for oral small-molecule therapies that target the well-validated GLP-1R for metabolic health.


Subject(s)
Glucagon-Like Peptide-1 Receptor , Hypoglycemic Agents , Animals , Glucagon-Like Peptide-1 Receptor/agonists , Humans , Hypoglycemic Agents/pharmacology , Peptides/chemistry
2.
Gastroenterology ; 161(2): 536-547.e2, 2021 08.
Article in English | MEDLINE | ID: mdl-33848536

ABSTRACT

OBJECTIVE: Hypothalamic melanocortin 4 receptors (MC4R) are a key regulator of energy homeostasis. Brain-penetrant MC4R agonists have failed, as concentrations required to suppress food intake also increase blood pressure. However, peripherally located MC4R may also mediate metabolic benefits of MC4R activation. Mc4r transcript is enriched in mouse enteroendocrine L cells and peripheral administration of the endogenous MC4R agonist, α-melanocyte stimulating hormone (α-MSH), triggers the release of the anorectic hormones Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) in mice. This study aimed to determine whether pathways linking MC4R and L-cell secretion exist in humans. DESIGN: GLP-1 and PYY levels were assessed in body mass index-matched individuals with or without loss-of-function MC4R mutations following an oral glucose tolerance test. Immunohistochemistry was performed on human intestinal sections to characterize the mucosal MC4R system. Static incubations with MC4R agonists were carried out on human intestinal epithelia, GLP-1 and PYY contents of secretion supernatants were assayed. RESULTS: Fasting PYY levels and oral glucose-induced GLP-1 secretion were reduced in humans carrying a total loss-of-function MC4R mutation. MC4R was localized to L cells and regulates GLP-1 and PYY secretion from ex vivo human intestine. α-MSH immunoreactivity in the human intestinal epithelia was predominantly localized to L cells. Glucose-sensitive mucosal pro-opiomelanocortin cells provide a local source of α-MSH that is essential for glucose-induced GLP-1 secretion in small intestine. CONCLUSION: Our findings describe a previously unidentified signaling nexus in the human gastrointestinal tract involving α-MSH release and MC4R activation on L cells in an autocrine and paracrine fashion. Outcomes from this study have direct implications for targeting mucosal MC4R to treat human metabolic disorders.


Subject(s)
Enteroendocrine Cells/metabolism , Glucagon-Like Peptide 1/metabolism , Intestinal Mucosa/metabolism , Peptide YY/metabolism , Pro-Opiomelanocortin/metabolism , Receptor, Melanocortin, Type 4/metabolism , alpha-MSH/metabolism , Autocrine Communication , Blood Glucose/metabolism , Case-Control Studies , Enteroendocrine Cells/drug effects , Glucose/administration & dosage , Glucose Tolerance Test , Humans , Intestinal Mucosa/drug effects , Loss of Function Mutation , Paracrine Communication , Pro-Opiomelanocortin/genetics , Receptor, Melanocortin, Type 4/agonists , Receptor, Melanocortin, Type 4/genetics , Secretory Pathway , Signal Transduction , Time Factors , alpha-MSH/pharmacology
3.
Diabet Med ; 36(11): 1367-1374, 2019 11.
Article in English | MEDLINE | ID: mdl-31466128

ABSTRACT

AIM: To investigate the incretin axis in people with cystic fibrosis. METHODS: Adults with cystic fibrosis-related diabetes, cystic fibrosis without diabetes, and controls (adults without cystic fibrosis and without diabetes) underwent an oral glucose tolerance test and then a closely matched isoglycaemic i.v. glucose infusion. On each occasion, glucose, insulin, C-peptide, total and active glucagon-like peptide-1 and gastric inhibitory polypeptide responses were recorded and incremental areas under curves were calculated for 60 and 240 min. RESULTS: Five adults with cystic fibrosis-related diabetes, six with cystic fibrosis without diabetes and six controls, matched for age and BMI, completed the study. Glucose during oral glucose tolerance test closely matched those during isoglycaemic i.v. glucose infusion. The calculated incretin effect was similar in the control group and the cystic fibrosis without diabetes group (28% and 29%, respectively), but was lost in the cystic fibrosis-related diabetes group (cystic fibrosis-related diabetes vs control group: -6% vs 28%; p=0.03). No hyposecretion of glucagon-like peptide-1 or gastric inhibitory polypeptide was observed; conversely, 60-min incremental area under the curve for total glucagon-like peptide-1 was significantly higher in the cystic fibrosis-related diabetes group than in the control group [1070.4 (254.7) vs 694.97 (308.1); p=0.03] CONCLUSIONS: The incretin effect was lost in cystic fibrosis-related diabetes despite adequate secretion of the incretin hormones. These data support the concept that reduced incretin hormone insulinotropic activity contributes significantly to postprandial hyperglycaemia in cystic fibrosis-related diabetes.


Subject(s)
Cystic Fibrosis/physiopathology , Diabetes Mellitus/physiopathology , Glucose/administration & dosage , Hyperglycemia/physiopathology , Incretins/blood , Adult , C-Peptide/blood , Cystic Fibrosis/complications , Diabetes Mellitus/blood , Diabetes Mellitus/drug therapy , Diabetes Mellitus/etiology , Female , Gastric Inhibitory Polypeptide/blood , Glucagon-Like Peptide 1/blood , Glucose/metabolism , Glucose Tolerance Test , Humans , Hyperglycemia/blood , Infusions, Intravenous , Insulin/blood , Male
4.
J Invertebr Pathol ; 166: 107212, 2019 09.
Article in English | MEDLINE | ID: mdl-31254496

ABSTRACT

Snails of the species Pseudosuccinea columella are considered intermediate hosts of Fasciola hepatica, a digenetic trematode that infects bile ducts of ruminants and humans, causing economic damage and serious problems for public health. These gastropods inhabit ponds, have high reproductive capacity, and lay their egg masses in submerged substrates on pond edges where they are exposed to desiccation and microbes, including fungi, that may exert pathogenic effects on the snail and its embryos. This information is relevant for control of the intermediate host and therefore of fasciolosis. With the objective of evaluating ovicidal potential of Pochonia chlamydosporia (Pc-10 isolate), a nematophagous fungus used as antagonistic agent for a wide variety of helminths of medical and veterinary importance, on egg masses of P. columella, we compared a treated group, where the egg masses were exposed to Pc-10 for a period of 25 days, and a control group, in which there was no exposure to the fungus. The results indicated that the embryogenesis process was significantly inhibited (93.15%) by Pc-10, suggesting its applicability in biological control programs of lymnaeid snails. In addition, ultrastructure showed the occurrence of different types of interactions between the egg masses with the mycelia of Pc-10: type 1, biochemical effects by the adherence of hyphae; type 2, morphological alterations, but without hyphal penetration; and type 3, lytic effect, morphological damage caused by penetration of hyphae by the fungus, resulting in some important structural modifications, thus compromising the viability of the eggs. The results demonstrate the susceptibility of P. columella egg masses to an isolate of P. chlamydosporia under laboratory conditions, providing valuable information for the biological control of this intermediate host.


Subject(s)
Ascomycota , Ovum , Pest Control, Biological/methods , Snails/parasitology , Animals , Disease Vectors , Fascioliasis/prevention & control
5.
Biochemistry ; 58(23): 2665-2669, 2019 06 11.
Article in English | MEDLINE | ID: mdl-31140787

ABSTRACT

Pyrroloquinoline quinone (PQQ) is an essential redox cofactor in bacterial calcium- and lanthanide-dependent alcohol dehydrogenases. Although certain bacteria are known to synthesize and secrete PQQ, little is known about trafficking of this cofactor within and between cells. Here, we show that a previously uncharacterized periplasmic (solute) binding protein from Methylobacterium extorquens AM1, here renamed PqqT, binds 1 equiv of PQQ with high affinity ( Kd = 50 nM). UV-visible and spectrofluorometric titrations establish that PqqT binds an unhydrated form of PQQ with distinct spectral features from the cofactor in free solution. To our knowledge, PqqT is the first solute-binding protein identified for PQQ and the first protein implicated in cellular trafficking of the cofactor. We propose that PqqT, which is encoded adjacent to a putative ATP-binding cassette transporter in the M. extorquens genome, is involved in uptake of exogenous PQQ to supplement endogenous cofactor biosynthesis. These results support the emerging importance of PQQ transfer within microbial and microbe-host communities.


Subject(s)
Bacterial Proteins/metabolism , PQQ Cofactor/metabolism , Periplasmic Binding Proteins/metabolism , Amino Acid Substitution , Bacterial Proteins/genetics , Escherichia coli/genetics , Methylobacterium extorquens/chemistry , Periplasmic Binding Proteins/genetics , Protein Binding , Thermodynamics
6.
J Am Chem Soc ; 141(7): 2857-2861, 2019 02 20.
Article in English | MEDLINE | ID: mdl-30726674

ABSTRACT

Sensitive yet rapid methods for detection of rare earth elements (REEs), including lanthanides (Lns), would facilitate mining and recycling of these elements. Here we report a highly selective, genetically encoded fluorescent sensor for Lns, LaMP1, based on the recently characterized protein, lanmodulin. LaMP1 displays a 7-fold ratiometric response to all LnIIIs, with apparent Kds of 10-50 pM but only weak response to other common divalent and trivalent metal ions. We use LaMP1 to demonstrate for the first time that a Ln-utilizing bacterium, Methylobacterium extorquens, selectively transports early Lns (LaIII-NdIII) into its cytosol, a surprising observation as the only Ln-proteins identified to date are periplasmic. Finally, we apply LaMP1 to suggest the existence of a LnIII uptake system utilizing a secreted metal chelator, akin to siderophore-mediated FeIII acquisition. LaMP1 not only sheds light on Ln biology but also may be a useful technology for detecting and quantifying REEs in environmental and industrial samples.

7.
Nutrients ; 11(2)2019 Jan 22.
Article in English | MEDLINE | ID: mdl-30678223

ABSTRACT

Gut-derived serotonin (5-HT) is released from enterochromaffin (EC) cells in response to nutrient cues, and acts to slow gastric emptying and modulate gastric motility. Rodent studies also evidence a role for gut-derived 5-HT in the control of hepatic glucose production, lipolysis and thermogenesis, and in mediating diet-induced obesity. EC cell number and 5-HT content is increased in the small intestine of obese rodents and human, however, it is unknown whether EC cells respond directly to glucose in humans, and whether their capacity to release 5-HT is perturbed in obesity. We therefore investigated 5-HT release from human duodenal and colonic EC cells in response to glucose, sucrose, fructose and α-glucoside (αMG) in relation to body mass index (BMI). EC cells released 5-HT only in response to 100 and 300 mM glucose (duodenum) and 300 mM glucose (colon), independently of osmolarity. Duodenal, but not colonic, EC cells also released 5-HT in response to sucrose and αMG, but did not respond to fructose. 5-HT content was similar in all EC cells in males, and colonic EC cells in females, but 3 to 4-fold higher in duodenal EC cells from overweight females (p < 0.05 compared to lean, obese). Glucose-evoked 5-HT release was 3-fold higher in the duodenum of overweight females (p < 0.05, compared to obese), but absent here in overweight males. Our data demonstrate that primary human EC cells respond directly to dietary glucose cues, with regional differences in selectivity for other sugars. Augmented glucose-evoked 5-HT release from duodenal EC is a feature of overweight females, and may be an early determinant of obesity.


Subject(s)
Body Weight , Carbohydrates/pharmacology , Enterochromaffin Cells/drug effects , Gastrointestinal Tract/cytology , Cells, Cultured , Dose-Response Relationship, Drug , Female , Humans , Male , Sex Factors
8.
Ann Oncol ; 30(2): 274-280, 2019 02 01.
Article in English | MEDLINE | ID: mdl-30395144

ABSTRACT

BACKGROUND: Hospitalized patients with cancer experience a high symptom burden, which is associated with poor health outcomes and increased health care utilization. However, studies investigating symptom monitoring interventions in this population are lacking. We conducted a pilot randomized trial to assess the feasibility and preliminary efficacy of a symptom monitoring intervention to improve symptom management in hospitalized patients with advanced cancer. PATIENTS AND METHODS: We randomly assigned patients with advanced cancer who were admitted to the inpatient oncology service to a symptom monitoring intervention or usual care. Patients in both arms self-reported their symptoms daily (Edmonton Symptom Assessment System and Patient Health Questionnaire-4). Patients assigned to the intervention had their symptom reports presented graphically with alerts for moderate/severe symptoms during daily team rounds. The primary end point of the study was feasibility. We defined the intervention as feasible if >75% of participants hospitalized >2 days completed >2 symptom reports. We observed daily rounds to determine whether clinicians discussed and developed a plan to address patients' symptoms. We used regression models to assess intervention effects on patients' symptoms throughout their hospitalization, readmission risk, and hospital length of stay (LOS). RESULTS: Among 150 enrolled patients (81.1% enrollment), 94.2% completed >2 symptom reports. Clinicians discussed 60.4% of the symptom reports and developed a plan to address the symptoms highlighted by the symptom reports 20.8% of the time. Compared with usual care, intervention patients had a greater proportion of days with lower psychological distress (B = 0.12, P = 0.008), but no significant difference in the proportion of days with improved Edmonton Symptom Assessment System-physical symptoms (B = 0.07, P = 0.138). Intervention patients had lower readmission risk (hazard ratio = 0.68, P = 0.224), although this difference was not significant. We found no significant intervention effects on hospital LOS (B = 0.16, P = 0.862). CONCLUSIONS: This symptom monitoring intervention is feasible and demonstrates encouraging preliminary efficacy for improving patients' symptoms and readmission risk.ClinicalTrials.gov identifier NCT02891993.


Subject(s)
Hospitalization/statistics & numerical data , Monitoring, Ambulatory/methods , Neoplasms/psychology , Neoplasms/therapy , Patient Acceptance of Health Care/statistics & numerical data , Symptom Assessment/methods , Telemedicine , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pilot Projects , Prognosis , Psychometrics , Quality of Life , Self Report , Severity of Illness Index , Young Adult
9.
Parasitol Res ; 117(12): 3927-3934, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30353231

ABSTRACT

Postharmostomum commutatum (Dietz, 1858), a parasite of the caeca of poultry, has been reported from many different parts of the world. Despite its importance, there are no molecular sequences available and its phylogenetic position is unknown in relation to other members of Brachylaimoidea, a group in which taxonomic confusion reigns. Here, morphological and molecular techniques were used to study digeneans from the caeca of free-range chickens found naturally infected in the municipality of Viçosa, state of Minas Gerais, Brazil, between August 2017 and May 2018. The specimens were identified as P. commutatum, with Postharmostomum gallinum Witenberg, 1923 herein considered a junior synonym. Sequences obtained for the 28S, ITS2, and cox-1 genes were compared with sequences available from other species of Brachylaimoidea. Phylogenetic analysis of the three markers indicates P. commutatum formed an isolated lineage from other brachylaimoids, supporting the distinct status of the genus. The topology of phylogenetic trees obtained suggests that the morphology-based classification of families of Brachylaimoidea is artificial and new rearrangements of some genera or creation of new families may be necessary. The sequences newly obtained here will be useful for testing the cosmopolitan distribution of P. commutatum.


Subject(s)
Cecum/parasitology , Chickens/parasitology , Trematoda/classification , Trematoda/genetics , Animals , Brazil , Cyclooxygenase 1/genetics , DNA, Helminth/genetics , DNA, Intergenic/genetics , Phylogeny , Poultry/parasitology , RNA, Ribosomal, 28S/genetics
10.
J Am Chem Soc ; 140(44): 15056-15061, 2018 11 07.
Article in English | MEDLINE | ID: mdl-30351021

ABSTRACT

Lanthanides (Lns) have been shown recently to be essential cofactors in certain enzymes in methylotrophic bacteria. Here we identify in the model methylotroph, Methylobacterium extorquens, a highly selective LnIII-binding protein, which we name lanmodulin (LanM). LanM possesses four metal-binding EF hand motifs, commonly associated with CaII-binding proteins. In contrast to other EF hand-containing proteins, however, LanM undergoes a large conformational change from a largely disordered state to a compact, ordered state in response to picomolar concentrations of all LnIII (Ln = La-Lu, Y), whereas it only responds to CaII at near-millimolar concentrations. Mutagenesis of conserved proline residues present in LanM's EF hands, not encountered in CaII-binding EF hands, to alanine pushes CaII responsiveness into the micromolar concentration range while retaining picomolar LnIII affinity, suggesting that these unique proline residues play a key role in ensuring metal selectivity in vivo. Identification and characterization of LanM provides insights into how biology selectively recognizes low-abundance LnIII over higher-abundance CaII, pointing toward biotechnologies for detecting, sequestering, and separating these technologically important elements.


Subject(s)
Bacterial Proteins/chemistry , Lanthanoid Series Elements/chemistry , Methylobacterium extorquens/chemistry , Bacterial Proteins/isolation & purification , Protein Binding
11.
An Acad Bras Cienc ; 90(1): 461-470, 2018.
Article in English | MEDLINE | ID: mdl-29641767

ABSTRACT

The aim of this study was to optimize the dextranase production by fungus Pochonia chlamydosporia (VC4) and evaluate its activity in dextran reduction in sugarcane juice. The effects, over the P. chlamydosporia dextranase production, of different components from the culture medium were analyzed by Plackett-Burman design and central composite design. The response surface was utilized to determine the levels that, among the variables that influence dextranase production, provide higher production of these enzymes. The enzymatic effect on the removal of dextran present in sugarcane juice was also evaluated. It was observed that only NaNO3 and pH showed significant effect (p<0.05) over dextranase production and was determined that the levels which provided higher enzyme production were, respectively, 5 g/L and 5.5. The dextranases produced by fungus P. chlamydosporia reduced by 75% the dextran content of the sugarcane juice once treated for 12 hours, when compared to the control treatment.


Subject(s)
Dextranase/biosynthesis , Hypocreales/enzymology , Models, Statistical , Saccharum/metabolism , Chemical Fractionation/methods , Culture Media/metabolism , Dextrans/metabolism , Electrophoresis, Polyacrylamide Gel , Enzyme Activation , Fruit and Vegetable Juices/analysis , Hydrogen-Ion Concentration , Nitrates , Temperature
12.
Int J Obes (Lond) ; 42(11): 1880-1889, 2018 11.
Article in English | MEDLINE | ID: mdl-29568107

ABSTRACT

BACKGROUND/OBJECTIVES: Evidence from animal studies highlights an important role for serotonin (5-HT), derived from gut enterochromaffin (EC) cells, in regulating hepatic glucose production, lipolysis and thermogenesis, and promoting obesity and dysglycemia. Evidence in humans is limited, although elevated plasma 5-HT concentrations are linked to obesity. SUBJECTS/METHODS: We assessed (i) plasma 5-HT concentrations before and during intraduodenal glucose infusion (4 kcal/min for 30 min) in non-diabetic obese (BMI 44 ± 4 kg/m2, N = 14) and control (BMI 24 ± 1 kg/m2, N = 10) subjects, (ii) functional activation of duodenal EC cells (immunodetection of phospho-extracellular related-kinase, pERK) in response to glucose, and in separate subjects, (iii) expression of tryptophan hydroxylase-1 (TPH1) in duodenum and colon (N = 39), and (iv) 5-HT content in primary EC cells from these regions (N = 85). RESULTS: Plasma 5-HT was twofold higher in obese than control responders prior to (P = 0.025), and during (iAUC, P = 0.009), intraduodenal glucose infusion, and related positively to BMI (R2 = 0.334, P = 0.003) and HbA1c (R2 = 0.508, P = 0.009). The density of EC cells in the duodenum was twofold higher at baseline in obese subjects than controls (P = 0.023), with twofold more EC cells activated by glucose infusion in the obese (EC cells co-expressing 5-HT and pERK, P = 0.001), while the 5-HT content of EC cells in duodenum and colon was similar; TPH1 expression was 1.4-fold higher in the duodenum of obese subjects (P = 0.044), and related positively to BMI (R2 = 0.310, P = 0.031). CONCLUSIONS: Human obesity is characterized by an increased capacity to produce and release 5-HT from the proximal small intestine, which is strongly linked to higher body mass, and glycemic control. Gut-derived 5-HT is likely to be an important driver of pathogenesis in human obesity and dysglycemia.


Subject(s)
Colon/cytology , Enterochromaffin Cells/metabolism , Obesity/physiopathology , Peripheral Nervous System/physiology , Serotonin/metabolism , Adult , Blood Glucose/metabolism , Cells, Cultured , Colon/metabolism , Endoscopy, Gastrointestinal , Female , Humans , Male , Middle Aged , Obesity/metabolism , Peripheral Nervous System/metabolism , Real-Time Polymerase Chain Reaction , Signal Transduction
13.
An. acad. bras. ciênc ; 90(1): 461-470, Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-886908

ABSTRACT

ABSTRACT The aim of this study was to optimize the dextranase production by fungus Pochonia chlamydosporia (VC4) and evaluate its activity in dextran reduction in sugarcane juice. The effects, over the P. chlamydosporia dextranase production, of different components from the culture medium were analyzed by Plackett-Burman design and central composite design. The response surface was utilized to determine the levels that, among the variables that influence dextranase production, provide higher production of these enzymes. The enzymatic effect on the removal of dextran present in sugarcane juice was also evaluated. It was observed that only NaNO3 and pH showed significant effect (p<0.05) over dextranase production and was determined that the levels which provided higher enzyme production were, respectively, 5 g/L and 5.5. The dextranases produced by fungus P. chlamydosporia reduced by 75% the dextran content of the sugarcane juice once treated for 12 hours, when compared to the control treatment.


Subject(s)
Models, Statistical , Saccharum/metabolism , Dextranase/biosynthesis , Hypocreales/enzymology , Temperature , Dextrans/metabolism , Culture Media/metabolism , Electrophoresis, Polyacrylamide Gel , Enzyme Activation , Fruit and Vegetable Juices/analysis , Chemical Fractionation/methods , Hydrogen-Ion Concentration , Nitrates
14.
J Biol Chem ; 292(37): 15456-15467, 2017 09 15.
Article in English | MEDLINE | ID: mdl-28747433

ABSTRACT

TsrM catalyzes the methylation of C2 in l-tryptophan (Trp). This reaction is the first step in the biosynthesis of the quinaldic acid moiety of the thiopeptide antibiotic thiostrepton, which exhibits potent activity against Gram-positive pathogens. TsrM is a member of the radical S-adenosylmethionine (SAM) superfamily of enzymes, but it does not catalyze the formation of 5'-deoxyadenosin-5'-yl or any other SAM-derived radical. In addition to a [4Fe-4S] cluster, TsrM contains a cobalamin cofactor that serves as an intermediate methyl carrier in its reaction. However, how this cofactor donates a methyl moiety to the Trp substrate is unknown. Here, we showed that the unmodified N1 position of Trp is important for turnover and that 1-thia-Trp and 1-oxa-Trp serve as competitive inhibitors. We also showed that ß-cyclopropyl-Trp undergoes C2 methylation in the absence of cyclopropyl ring opening, disfavoring mechanisms that involve unpaired electron density at C3 of the indole ring. Moreover, we showed that all other indole-substituted analogs of Trp undergo methylation at varying but measurable rates and that the analog 7-aza-Trp, which is expected to temper the nucleophilicity of C2 in Trp, is a very poor substrate. Last, no formation of cob(II)alamin or substrate radicals was observed during the reaction with Trp or any molecule within a tested panel of Trp analogs. In summary, our results are most consistent with a mechanism that involves two polar nucleophilic displacements, the second of which requires deprotonation of the indole nitrogen in Trp during its attack on methylcobalamin.


Subject(s)
Bacterial Proteins/metabolism , Methyltransferases/metabolism , S-Adenosylmethionine/metabolism , Staphylococcus/enzymology , Tryptophan/metabolism , Vitamin B 12/chemistry , Bacterial Proteins/antagonists & inhibitors , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Biocatalysis , Electron Spin Resonance Spectroscopy , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Enzyme Stability/drug effects , Kinetics , Methylation/drug effects , Methyltransferases/antagonists & inhibitors , Methyltransferases/chemistry , Methyltransferases/genetics , Molecular Structure , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , S-Adenosylmethionine/chemistry , Spectrophotometry , Substrate Specificity , Thiostrepton/biosynthesis , Tryptophan/analogs & derivatives , Tryptophan/chemistry
15.
Ir J Med Sci ; 186(2): 393-397, 2017 May.
Article in English | MEDLINE | ID: mdl-26969456

ABSTRACT

BACKGROUND: There are currently no Irish guidelines on screening for Chlamydia trachomatis infection in pregnancy. Prevalence rates in the antenatal population are not known which has prevented the development of screening recommendations for this group. AIMS: The objective of this study was to determine the prevalence of asymptomatic urogenital C. trachomatis infection in young women attending for care at a large maternity hospital. METHODS: All patients aged 25 years and under attending the Hospital between December 2011 and December 2013 were offered screening for urogenital C. trachomatis infection. Nucleic acid amplification testing of the C. trachomatis cryptic plasmid was performed on either endocervical swabs or first void urine samples. RESULTS: There were 2687 women tested for C. trachomatis infection, 83.4 % (2241/2687) through the antenatal clinics, 7.1 % (193/2687) through the gynaecology clinic, and 9.4 % (253/2687) through the emergency department. The rate of a positive test result was 5.6 % (151/2687) overall. The rates in women ages 16-18, 19-21 and 22-25 years were 9.1 % (31/340), 6.5 % (50/774) and 4.4 % (69/1561), respectively. A positive test result was more likely in those who were unemployed (p = 0.04), those who were Irish (p = 0.03) and those who were unmarried (p < 0.01). There were no cases of neonatal C. trachomatis infection in babies born to mothers who were screened in early pregnancy. CONCLUSIONS: The prevalence rate of detected C. trachomatis infection was 5.6 % in the study population. Screening of antenatal patients may have a role in preventing vertical transmission of infection to the neonate.


Subject(s)
Chlamydia Infections/diagnosis , Chlamydia trachomatis/isolation & purification , Pregnancy Complications, Infectious/diagnosis , Adolescent , Adult , Ambulatory Care Facilities , Chlamydia Infections/epidemiology , Female , Hospitals, Maternity , Humans , Infant, Newborn , Pilot Projects , Pregnancy , Prevalence , Young Adult
16.
Br J Clin Pharmacol ; 83(2): 326-338, 2017 02.
Article in English | MEDLINE | ID: mdl-27621150

ABSTRACT

AIM: To evaluate safety, tolerability and pharmacokinetics of oral PF-05190457, an oral ghrelin receptor inverse agonist, in healthy adults. METHODS: Single (SAD) and multiple ascending dose (MAD) studies were randomised, placebo-controlled, double-blind studies. Thirty-five healthy men (age 38.2 ± 10.4 years; body mass index 24.8 ± 3.1 kg m-2 [mean ± standard deviation]) received ≥1 dose (2, 10, 40 [divided], 50, 100, 150, and 300 [single or divided] mg) of PF-05190457 and/or placebo in the SAD. In the MAD study, 35 healthy men (age 39.7 ± 10.1 years; body mass index 25.9 ± 3.3 kg m-2 ) received ≥1 dose (2, 10, 40 and 100 mg twice daily) of PF-05190457 and/or placebo daily for 2 weeks. RESULTS: PF-05190457 absorption was rapid with a Tmax of 0.5-3 hours and a half-life between 8.2-9.8 hours. PF-05190457 dose-dependently blocked ghrelin (1 pmol kg-1  min-1 )-induced growth hormone (GH) release with (mean [90% confidence interval]) 77% [63-85%] inhibition at 100 mg. PF-05190457 (150 mg) delayed gastric emptying lag time by 30% [7-58%] and half emptying time by 20% [7-35%] with a corresponding decrease in postprandial glucose by 9 mg dL-1 . The most frequent adverse event reported by 30 subjects at doses ≥50 mg was somnolence. PF-05190457 plasma concentrations also increased heart rate up to 13.4 [4.8-58.2] beats min-1 and, similar to the effect on glucose and ghrelin-induced GH, was lost within 2 weeks. CONCLUSIONS: PF-05190457 is a well-tolerated first-in-class ghrelin receptor inverse agonist with acceptable pharmacokinetics for oral daily dosing. Blocking ghrelin receptors inhibits ghrelin-induced GH, and increases heart rate, effects that underwent tachyphylaxis with chronic dosing. PF-051940457 has the potential to treat centrally-acting disorders such as insomnia.


Subject(s)
Azetidines/administration & dosage , Drug Inverse Agonism , Receptors, Ghrelin/agonists , Spiro Compounds/administration & dosage , Administration, Oral , Adult , Azetidines/pharmacokinetics , Azetidines/pharmacology , Dose-Response Relationship, Drug , Double-Blind Method , Half-Life , Heart Rate/drug effects , Humans , Male , Middle Aged , Spiro Compounds/pharmacokinetics , Spiro Compounds/pharmacology
17.
Ann Oncol ; 27(8): 1607-12, 2016 08.
Article in English | MEDLINE | ID: mdl-27177859

ABSTRACT

BACKGROUND: Family caregivers (FCs) are critically important for patients with cancer, yet they may experience psychological distress related to caregiving demands. We sought to describe rates of depression and anxiety in FCs of patients with incurable cancer and identify factors associated with these symptoms to determine those at greatest risk for psychological distress. PATIENTS AND METHODS: We performed a cross-sectional analysis of baseline data from a randomized trial of early palliative care. We assessed depression and anxiety using the Hospital Anxiety and Depression Scale in patients within 8 weeks of diagnosis of incurable lung or gastrointestinal cancer and their FCs. We also assessed patients' quality of life (Functional Assessment of Cancer Therapy-General), coping strategies (Brief COPE), and their report of the primary goal of their cancer treatment. We used linear regression with purposeful selection of covariates to identify factors associated with FC depression and anxiety symptoms. RESULTS: We enrolled 78.6% (n = 275) of potentially eligible FCs. The majority were female (69.1%) and married to the patient (66.2%). While the proportion of FCs and patients reporting depression did not differ (16.4% versus 21.5%, P = 0.13), FCs were more likely to report anxiety compared with patients (42.2% versus 28.4%, P < 0.001). Patients' use of acceptance coping was associated with lower FC depression (B = -0.42, P < 0.001), while emotional support coping was associated with higher FC depression (B = 0.69, P = 0.001) and lower FC anxiety (B = -0.70, P < 0.001). Patient report that their primary goal of their treatment was to 'cure my cancer' was associated with higher FC depression (B = 0.72, P = 0.03). CONCLUSIONS: Patients with incurable cancer and their FCs report high levels of depression and anxiety symptoms. We demonstrated that patients' coping strategies and prognostic understanding were associated with FC depression and anxiety symptoms, underscoring the importance of targeting these risk factors when seeking to address the psychological distress experienced by FCs.


Subject(s)
Anxiety Disorders/psychology , Caregivers/psychology , Depression/psychology , Gastrointestinal Neoplasms/psychology , Lung Neoplasms/psychology , Aged , Anxiety Disorders/physiopathology , Cross-Sectional Studies , Depression/physiopathology , Emotions/physiology , Female , Gastrointestinal Neoplasms/physiopathology , Humans , Lung Neoplasms/physiopathology , Male , Middle Aged , Palliative Care/psychology , Quality of Life , Surveys and Questionnaires
18.
Water Sci Technol ; 73(11): 2590-9, 2016.
Article in English | MEDLINE | ID: mdl-27232394

ABSTRACT

This study sought to investigate and compare bacterial contamination levels at six different sites along the Diep and Plankenburg river systems in the Western Cape, South Africa. Surface water and sediment samples were collected monthly from the six selected sampling sites along both river courses between January 2014 and December 2014 and were evaluated for bacterial contaminants. Microbial isolation, characterisation and identification were done using conventional techniques (serial dilution, Gram staining, and biochemical testing) and molecular identification techniques (polymerase chain reaction and DNA sequencing). A total of 19 bacterial isolates belonging to the genera Raoultella, Bacillus, Pseudomonas, Klebsiella, Escherichia, Enterobacter, Exiguobacterium, Acinetobacter, Serratia, Aeromonas, Staphylococcus and Citrobacter were isolated from the surface water and sediment samples at the end of the survey. Higher microbial load was obtained from sediment samples compared to surface water samples. Seasonal variation was also observed in terms of microbial counts. Higher microbial counts were obtained during summer sampling time compared to winter sampling time. The most contaminated site was located on Plankenburg River with average bacterial counts ranging between 3.1 × 10(5)-6.9 × 10(8) CFU/ml and 3.9 × 10(6)-2.88 × 10(9) CFU/ml from surface water and sediment, respectively, recorded at this site during winter and summer. Although lower microbial counts were recorded along the Diep River course, most of the bacterial counts recorded along both rivers exceeded the acceptable maximum limits for river water.


Subject(s)
Environmental Pollution/analysis , Rivers/microbiology , Water Microbiology , Bacterial Load , Enterobacteriaceae/isolation & purification , Environmental Monitoring , Seasons , South Africa
19.
Br J Pharmacol ; 173(9): 1452-64, 2016 May.
Article in English | MEDLINE | ID: mdl-26784385

ABSTRACT

BACKGROUND AND PURPOSE: Ghrelin increases growth hormone secretion, gastric acid secretion, gastric motility and hunger but decreases glucose-dependent insulin secretion and insulin sensitivity in humans. Antagonizing the ghrelin receptor has potential as a therapeutic approach in the treatment of obesity and type 2 diabetes. Therefore, the aim was to pharmacologically characterize the novel small-molecule antagonist PF-05190457 and assess translational pharmacology ex vivo. EXPERIMENTAL APPROACH: Radioligand binding in filter and scintillation proximity assay formats were used to evaluate affinity, and europium-labelled GTP to assess functional activity. Rat vagal afferent firing and calcium imaging in dispersed islets were used as native tissues underlying food intake and insulin secretion respectively. KEY RESULTS: PF-05190457 was a potent and selective inverse agonist on constitutively active ghrelin receptors and acted as a competitive antagonist of ghrelin action, with a human Kd of 3 nM requiring 4 h to achieve equilibrium. Potency of PF-05190457 was similar across different species. PF-05190457 increased intracellular calcium within dispersed islets and increased vagal afferent firing in a concentration-dependent manner with similar potency but was threefold less potent as compared with the in vitro Ki in recombinant overexpressing cells. The effect of PF-05190457 on rodent islets was comparable with glibenclamide, but glucose-dependent and additive with the insulin secretagogue glucagon-like peptide-1. CONCLUSIONS AND IMPLICATIONS: Together, these data provide the pharmacological in vitro and ex vivo characterization of the first ghrelin receptor inverse agonist, which has advanced into clinical trials to evaluate the therapeutic potential of blocking ghrelin receptors in obesity and type 2 diabetes.


Subject(s)
Azetidines/pharmacology , Drug Inverse Agonism , Glucose/metabolism , Insulin/metabolism , Receptors, Ghrelin/antagonists & inhibitors , Spiro Compounds/pharmacology , Vagus Nerve/drug effects , Animals , Azetidines/chemistry , Calcium/metabolism , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Insulin Secretion , Male , Rats , Rats, Sprague-Dawley , Spiro Compounds/chemistry , Structure-Activity Relationship , Vagus Nerve/metabolism , Vagus Nerve/physiology
20.
Br Dent J ; 219(11): 521-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26657435

ABSTRACT

3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.


Subject(s)
Dental Instruments , Dentistry/methods , Printing, Three-Dimensional , Computer-Aided Design , Dental Implants , Dental Prosthesis Design/instrumentation , Dental Prosthesis Design/methods , Dental Restoration, Permanent/instrumentation , Dental Restoration, Permanent/methods , Humans
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