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Bell DJ, Kosterlitz H. Liver glycogen: Acyl derivatives and "regenerated glycogens". Biochem J 2006; 29:2027-30. [PMID: 16745872 PMCID: PMC1266720 DOI: 10.1042/bj0292027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bacon JS, Baldwin E, Bell DJ. Glycogen: 9. The magnitude of the ;unit chains' of liver glycogen of rabbits supplied with glucose, fructose and sucrose. Biochem J 2006; 38:198-201. [PMID: 16747775 PMCID: PMC1258060 DOI: 10.1042/bj0380198] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bell DJ. Liver glycogen: Molecular structure of glycogen formed after ingestion of galactose by fasted rabbits. Biochem J 2006; 30:1612-6. [PMID: 16746200 PMCID: PMC1263231 DOI: 10.1042/bj0301612] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Pontier SM, Lahaie N, Ginham R, St-Gelais F, Bonin H, Bell DJ, Flynn H, Trudeau LE, McIlhinney J, White JH, Bouvier M. Coordinated action of NSF and PKC regulates GABAB receptor signaling efficacy. EMBO J 2006; 25:2698-709. [PMID: 16724110 PMCID: PMC1500845 DOI: 10.1038/sj.emboj.7601157] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 04/27/2006] [Indexed: 01/27/2023] Open
Abstract
The obligatory heterodimerization of the GABAB receptor (GBR) raises fundamental questions about molecular mechanisms controlling its signaling efficacy. Here, we show that NEM sensitive fusion (NSF) protein interacts directly with the GBR heterodimer both in rat brain synaptosomes and in CHO cells, forming a ternary complex that can be regulated by agonist stimulation. Inhibition of NSF binding with a peptide derived from GBR2 (TAT-Pep-27) did not affect basal signaling activity but almost completely abolished agonist-promoted GBR desensitization in both CHO cells and hippocampal slices. Taken with the role of PKC in the desensitization process, our observation that TAT-Pep-27 prevented both agonist-promoted recruitment of PKC and receptor phosphorylation suggests that NSF is a priming factor required for GBR desensitization. Given that GBR desensitization does not involve receptor internalization, the NSF/PKC coordinated action revealed herein suggests that NSF can regulate GPCR signalling efficacy independently of its role in membrane trafficking. The functional interaction between three bona fide regulators of neurotransmitter release, such as GBR, NSF and PKC, could shed new light on the modulation of presynaptic GBR action.
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Graham SM, Bell DJ, Nyirongo S, Hartkoorn R, Ward SA, Molyneux EM. Low levels of pyrazinamide and ethambutol in children with tuberculosis and impact of age, nutritional status, and human immunodeficiency virus infection. Antimicrob Agents Chemother 2006; 50:407-13. [PMID: 16436690 PMCID: PMC1366879 DOI: 10.1128/aac.50.2.407-413.2006] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent pharmacokinetic studies that included children found that serum drug levels were low compared to those of adults for whom the same dosages were used. This study aimed to characterize the pharmacokinetics of pyrazinamide and ethambutol in Malawian children and to examine the impact of age, nutritional status, and human immunodeficiency virus (HIV) infection. We conducted a pharmacokinetic study of children treated for tuberculosis with thrice-weekly pyrazinamide (n = 27; mean age, 5.7 years) and of a separate group of children treated with thrice-weekly ethambutol (n = 18; mean age, 5.5 years) as portions of tablets according to national guidelines. Malnutrition and HIV infection were common in both groups. Blood samples were taken just prior to oral administration of the first dose, and subsequent samples were taken at intervals of 2, 3, 4, 7, 24, and 48 h after drug administration. Serum drug levels were low in all children for both drugs; in almost all cases, the maximum concentration of the drug in serum (Cmax) failed to reach the MIC for Mycobacterium tuberculosis. The Cmax of pyrazinamide was significantly lower in younger children (<5 years) than in older children. The Cmax of pyrazinamide was also lower for HIV-infected children and children with severe malnutrition, but these differences did not reach statistical significance. No differences were found for ethambutol in relation to age, HIV infection, or malnutrition, but the Cmax was <2 mg/liter in all cases. Studies of pharmacokinetic parameters and clinical outcomes obtained by using higher dosages of drugs for treatment of childhood tuberculosis are needed, and recommended dosages may need to be increased.
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Bell DJ, Woo EK. Re: AC Anyanwu, SM Moalypour. Are abdominal radiographs still overutilised in the assessment of acute abdominal pain? A district general hospital audit. J R Coll Surg Edinb Irel 1998;43(4): 267-70. Surgeon 2006; 4:61. [PMID: 16459505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Howlett DC, Menezes L, Bell DJ, Ahmed I, Witcher T, Bhatti N, Ramesar K, Williams MD. Ultrasound-guided core biopsy for the diagnosis of lumps in the neck: results in 82 patients. Br J Oral Maxillofac Surg 2005; 44:34-7. [PMID: 16214272 DOI: 10.1016/j.bjoms.2005.07.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 07/29/2005] [Indexed: 11/20/2022]
Abstract
Ultrasound-guided core biopsy of nodes (n = 78) and other lumps (n = 4) in the neck allowed a firm histological diagnosis in 76 of 82 patients (93%). Of the remaining six patients, histological examination was equivocal in four and valueless in two. Of 18 patients with a diagnosis of lymphoma only 3 required excision of the node to provide additional information for the planning of treatment.
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Abstract
Apoptosis is a key event in biologic homeostasis with particular importance to the immune system. It is an active energy-dependent process that is tightly regulated and controlled by a variety of signal transduction pathways. Apoptosis modulation plays a part in the pathogenesis of many human diseases, including HIV infection. Although multiple mechanisms may contribute to the decline in CD4 T-lymphocyte numbers observed, apoptosis is a significant factor. Alterations in levels of apoptosis are observed in both directly infected and uninfected bystander cells and a variety of pathways of apoptosis induction have been implicated. Apoptosis induction is related to death receptor and mitochondrial-induced pathways in specific circumstances. These events have been linked to individual HIV proteins and have been demonstrated to be altered by antiretroviral therapy.
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Fleishaker JC, Ryan KK, Jansat JM, Carel BJ, Bell DJ, Burke MT, Azie NE. Effect of MAO-A inhibition on the pharmacokinetics of almotriptan, an antimigraine agent in humans. Br J Clin Pharmacol 2001; 51:437-41. [PMID: 11422001 PMCID: PMC2014480 DOI: 10.1046/j.1365-2125.2001.01367.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To assess the effect of a reversible MAO-A inhibitor, moclobemide, on the single-dose pharmacokinetics of almotriptan and assess the clinical consequences of any interaction. METHODS Twelve healthy volunteers received the following treatments in a randomized, open-label, two-way crossover design (with a 1 week washout between treatments): (A) one 150 mg moclobemide tablet every 12 h for 8 days and one 12.5 mg almotriptan tablet on the morning of day 8; and (B) one 12.5 mg almotriptan tablet on day 8. Plasma almotriptan was quantified by h.p.l.c.-MS-MS, while urinary concentrations were measured by h.p.l.c.-u.v. Vital signs, ECGs, and adverse events were evaluated after almotriptan administration. Treatment effects on pharmacokinetics and vital signs were assessed by analysis of variance. RESULTS Mean almotriptan AUC was higher (483 +/- 99.9 vs 352 +/- 75.4 ng ml-1 h, P = 0.0001) and oral clearance was lower (26.6 +/- 4.00 vs 36.6 +/- 5.89 l h-1, P = 0.0001) when almotriptan was administered with moclobemide. Mean half-life was longer (4.22 +/- 0.78 vs 3.41 +/- 0.45 h, P = 0.0002) after coadministration with moclobemide. Renal clearance of almotriptan was unaffected by moclobemide. No serious adverse events occurred and no clinically significant vital sign changes were observed. CONCLUSIONS Moclobemide increased plasma concentrations of almotriptan on average by 37%, but the combined administration of these two compounds was well tolerated. The degree of interaction was much less than that seen previously for sumatriptan or zolmitriptan given with moclobemide.
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Bell DJ, Coster HGL, Smith JR. A computer based, four terminal impedance measuring system for low frequencies (designed for plasma membrane of living cells). ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3735/8/1/023] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Baker DM, Wang SL, Bell DJ, Drevon CA, Davis RA. One or more labile proteins regulate the stability of chimeric mRNAs containing the 3'-untranslated region of cholesterol-7alpha -hydroxylase mRNA. J Biol Chem 2000; 275:19985-91. [PMID: 10764793 DOI: 10.1074/jbc.m002351200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multiple AUUUA elements similar to those that regulate the degradation of several different mRNAs are conserved in the 3'-untranslated region (3'-UTR) of cholesterol-7alpha-hydroxylase (CYP7A1) mRNAs from several species. We examined if stabilization of mRNA decay could account for the >20-fold increase in the expression of CYP7A1 mRNA without a detectable change in transcription following dexamethasone treatment of rat hepatoma cells (L35 cells). Following RNA polymerase II-dependent transcription block or protein synthesis block, the decay of CYP7A1 mRNA displayed a short half-life ( approximately 30 min). Control experiments showed that in cells pre-treated with a RNA polymerase II inhibitor, dexamethasone had no detectable effect on CYP7A1 mRNA decay. Stable expression of luciferase reporter mRNAs in L35 cells showed that the CYP7A1 3'-UTR was required to observe a dexamethasone induction. To examine the hypothesis that a labile protein is required for dexamethasone-induced mRNA stabilization, cells were stably transfected with a tetracycline-repressible promoter that drives the expression of a green fluorescent protein analogue (ECFP) with or without the 3'-UTR of CYP7A1. Cells expressing ECFP with the 3'-UTR of CYP7A1 displayed a 3-fold dexamethasone induction of ECFP mRNA, whereas cells expressing ECFP without the 3'-UTR did not. Moreover, specific block of the transcription of ECFP containing the 3'-UTR by adding the tetracycline analogue doxycycline clearly displayed dexamethasone-induced stabilization of mRNA decay. These data provide compelling evidence that a putative labile protein and the 3'-UTR of CYP7A1 act together to decrease the rate of CYP7A1 mRNA degradation.
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Houge-Frydrych CS, Readshaw SA, Bell DJ. SB-219383, a novel tyrosyl tRNA synthetase inhibitor from a Micromonospora sp. II. Structure determination. J Antibiot (Tokyo) 2000; 53:351-6. [PMID: 10866216 DOI: 10.7164/antibiotics.53.351] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel tyrosyl tRNA synthetase inhibitor, SB-219383, has been isolated from a Micromonospora sp. The structure of SB-219383 has been elucidated by a combination of derivatisation, spectroscopic and other analytical techniques and found to be N-(L-tyrosyl)-2-amino[1(S*),3(S*),4(S*),5(R*),8(R*)-2,4,5,8-tetrahydroxy -7-oxa-2-azabicyclo[3.2.1]oct-3-y1]acetic acid (1).
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Cutler P, Bell DJ, Birrell HC, Connelly JC, Connor SC, Holmes E, Mitchell BC, Monté SY, Neville BA, Pickford R, Polley S, Schneider K, Skehel JM. An integrated proteomic approach to studying glomerular nephrotoxicity. Electrophoresis 1999; 20:3647-58. [PMID: 10612292 DOI: 10.1002/(sici)1522-2683(19991201)20:18<3647::aid-elps3647>3.0.co;2-#] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A single dose of puromycin aminonucleoside (PAN) given parenterally to rats induces ultrastructural glomerular changes and a nephrotic syndrome similar in many respects to human minimal change nephropathy. The exact aetiologies of both the human and the experimental syndromes are unknown, and are probably multifactorial. However, among the observed consequences in humans and rats is increased plasma protein excretion in urine, beginning in the latter typically 3-6 days after PAN administration. In view of this, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been used to profile urinary proteins during PAN-induced nephrotoxicity and subsequent recovery in the rat. In addition, urinary high performance liquid chromatography (HPLC) profiles and high resolution proton nuclear magnetic resonance (NMR) spectroscopy has been utilised to simultaneously detect toxin-induced changes in the relative concentrations of a number of metabolites. The proteomic approach, in conjunction with these other techniques, has the potential to provide significantly more mechanistic information than is provided readily by traditional clinical chemistry.
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Surridge AK, Ibrahim KM, Bell DJ, Webb NJ, Rico C, Hewitt GM. Fine-scale genetic structuring in a natural population of European wild rabbits (Oryctolagus cuniculus). Mol Ecol 1999; 8:299-307. [PMID: 10065544 DOI: 10.1046/j.1365-294x.1999.00570.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The genetic structure of a free-living tagged population of European wild rabbits (Oryctolagus cuniculus) was investigated for two consecutive years (1990 and 1991) using 10 polymorphic microsatellite loci. A specific social behaviour, the formation of stable breeding groups, influenced the genetic structure of the population. These breeding groups were shown to constitute genetically differentiated units with low levels of gene flow between them. The average relatedness among members of a social group was higher than within the population as a whole. As a result of female philopatry coupled with male-biased natal dispersal, the relatedness of females was higher than that of males, both within social groups and in the whole population. Furthermore, the average relatedness of females within groups was twice the relatedness of females between groups. This study reveals marked fine-scale, intrapopulation genetic structure, which is attributable to the social behaviour of the European wild rabbit.
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Bell DJ, Spitzer JC, Burns GL. Comparative effects of early weaning or once-daily suckling on occurrence of postpartum estrus in primiparous beef cows. Theriogenology 1998; 50:707-15. [PMID: 10734445 DOI: 10.1016/s0093-691x(98)00176-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We concurrently evaluated early weaning and once-daily suckling as options for shortening postpartum interval to estrus in primiparous cows calving in good body condition. Over 2 consecutive years, a total of 77 primiparous cows were assigned to 1 of 3 treatments: control (ad libitum suckling); once-daily suckling (for 30 d prior to start of breeding); or early weaning (calves weaned 30 d prior to start of breeding). All cows had a body condition score (BCS) of > or = 5 at parturition and were maintained in good condition throughout the breeding season. Cows were observed for estrus twice daily and blood samples for subsequent measurement of progesterone were collected at 48-h intervals. For data analysis, cows were divided into early- (> or = 85 d post partum) and late-calving (< 85 d post partum) groups at the onset of the breeding season. All calves were weighed at birth, at the onset of treatment, at weekly intervals until the start of the breeding season, and within 45 d of 205 d of age. Early weaning or once-daily suckling shortened the postpartum interval to first estrus of late-calving primiparous cows by 17 (P < 0.01) and 12 d (P < 0.08), respectively, compared with control group cows. However, among early-calving cows, neither early weaning nor once-daily suckling influenced the postpartum interval. Postpartum intervals of once-daily suckled cows and early-weaned cows were similar (P > 0.10).
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Hatcher JP, Bell DJ, Reed TJ, Hagan JJ. Chronic mild stress-induced reductions in saccharin intake depend upon feeding status. J Psychopharmacol 1998; 11:331-8. [PMID: 9443521 DOI: 10.1177/026988119701100408] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The consumption of a weak saccharin solution was examined in rats subjected to chronic mild stress (CMS). Intake of saccharin was reduced in stressed animals compared to isolated and group control animals but saccharin preference was not affected. Removal of water deprivation from the CMS schedule did not alter the effects of CMS upon saccharin intake. However, when food deprivation was omitted entirely from the CMS schedule the reduction in saccharin intake was eliminated. Similarly, in animals habituated to the full CMS procedure, reduction in saccharin intake was abolished by omitting food deprivation or by delaying the intake test for 24 h. Both CMS and food deprivation reduced water intake but had no effect on food consumed during the fluid-intake test. The presence of food deprivation during CMS appears to be a key factor affecting saccharin intake. Our data suggest that saccharin intake is not an appropriate measure of stress and anhedonia.
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Surridge AK, Bell DJ, Rico C, Hewitt GM. Polymorphic microsatellite loci in the European rabbit (Oryctolagus cuniculus) are also amplified in other lagomorph species. Anim Genet 1997; 28:302-5. [PMID: 9345727 DOI: 10.1111/j.1365-2052.1997.00137.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Six polymorphic microsatellite markers developed for the European wild rabbit (Oryctolagus cuniculus) were amplified with 20 other species of lagomorphs, representing both commercially important species and species important from a conservation perspective. Successful amplification of a number of these loci has provided an important set of new molecular markers for this mammalian order.
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