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Qiu X, Huang W, Yue W, Li D, Zhi J. Response of the serine/threonine kinase AKT and phosphoinositide-dependent kinase PDK in Frankliniella occidentalis (Thysanoptera: Thripidae) to three kinds of foods and their regulation of reproductive function. Insect Mol Biol 2024. [PMID: 38450915 DOI: 10.1111/imb.12905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/26/2024] [Indexed: 03/08/2024]
Abstract
Frankliniella occidentalis (Pergande) is a typical omnivorous insect that feeds on host plants, pollens and mite eggs, and poses a threat to crops worldwide. The insulin signalling pathway (ISP) is a typical nutrient-sensitive pathway that participates in the regulation of various functions in insects. Serine/threonine kinases (AKTs) and phosphoinositide-dependent kinases (PDKs) are key components of the ISP. In this study, the FoAKT and FoPDK genes in F. occidentalis were cloned, and the effects of three foods on their expression were determined. The expression of FoAKT and FoPDK in the thrips fed on kidney bean leaves supplemented with pine pollen or mite eggs was higher than in those primarily fed on leaves alone. Meanwhile, the fecundity of thrips fed on leaves supplemented with pine pollen was highest. In addition, RNA interference-mediated knockdown of FoAKT and FoPDK decreased vitellogenin (Vg) content and Vg expression in females, shortened ovariole length, delayed egg development and reduced fecundity and offspring hatching rates. Furthermore, the synthesis of juvenile hormone (JH) was reduced, and the contents of glucose, trehalose, glycogen and trehalase were affected. These results suggest that FoAKT and FoPDK regulate the reproduction of F. occidentalis by regulating Vg and JH production as well as carbohydrate metabolism.
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Affiliation(s)
- Xinyue Qiu
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China
| | - Wanqing Huang
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China
- Guizhou Provincial Tobacco Company, Tongren Branch, Tongren, China
| | - Wenbo Yue
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China
| | - Dingyin Li
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China
| | - Junrui Zhi
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China
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Li C, Hu C, Zhi J, Yue W, Li H. Effects of Nano-Graphene Oxide on the Growth and Reproductive Dynamics of Spodoptera frugiperda Based on an Age-Stage, Two-Sex Life Table. Insects 2022; 13:929. [PMID: 36292877 PMCID: PMC9604217 DOI: 10.3390/insects13100929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 10/08/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
The development and reproduction of the fall armyworm (FAW), Spodoptera frugiperda, which were reared on artificial diets containing nano-graphene oxide (GO), were determined based on age-stage, two-sex life table analysis. The results showed that GO had adverse effects on FAWs. Compared with the control, the duration of the egg stage and first, second, and sixth instar larval stages increased with increasing GO concentrations; however, the lifespan of male and female adults decreased with increasing GO concentrations. Weights of FAW pupae that were supplied with GO-amended diets increased by 0.17-15.20% compared to the control. Intrinsic growth, limited growth, and net reproductive rates of FAWs feeding on GO supplemented diets were significantly lower than the control, while mean generational periods (0.5 mg/g: 38.47; 1 mg/g: 40.38; 2 mg/g: 38.42) were significantly longer than the control. The expression of genes encoding vitellogenin (Vg) and vitellogenin receptor (VgR) expression was abnormal in female FAW adults feeding on GO-amended diets; the number of eggs laid decreased relative to the control, but Vg expression increased. In conclusion, GO prolonged the developmental period of FAWs, decreased fecundity, and led to a decline in the population size. The study provides a basis for the rational use of GO as a pesticide synergist for FAW control.
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Affiliation(s)
- Cao Li
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang 550005, China
| | - Chaoxing Hu
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang 550005, China
| | - Junrui Zhi
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang 550005, China
| | - Wenbo Yue
- The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang 550005, China
| | - Hongbo Li
- Institute of Plant Protection, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
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Li D, Zhi J, Yue W, Zhang T, Liu L. Resistance to Spinetoram Affects Host Adaptability of Frankliniella occidentalis (Thysanoptera: Thripidae) Based on Detoxifying Enzyme Activities and an Age-Stage-Two-Sex Life Table. Environ Entomol 2022; 51:780-789. [PMID: 35834261 DOI: 10.1093/ee/nvac053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Indexed: 06/15/2023]
Abstract
The western flower thrip (WFT) Frankliniella occidentalis (Pergande) is a serious agricultural pest with a wide host range which has developed resistance to several groups of insecticides. In this study, the effect of insecticide resistance on WFT host adaptability was explored by examining changes in detoxification enzyme activities and thrip development, and reproduction on preferred and less preferred host plants, eggplant Solanum melongena L. and broad bean Vicia faba L., respectively. Thrips were screened with spinetoram on kidney bean for six generations. Activities of glutathione S-transferase (GST), mixed function oxidases (MFOs), and cytochrome P450 enzyme (P450) in a resistant strain (RS) reared on broad bean were significantly higher than those in a sensitive strain (SS), and only carboxylesterase (CarE) increased in the RS when reared on eggplant, compared with the SS. Activities of the four detoxification enzymes in the RS reared on broad bean were significantly higher than in those reared-on eggplant. On broad bean, RS adult longevity was lower and developmental duration of offspring was shorter than those of the SS, but fecundity increased. On eggplant, RS fecundity was lower and developmental duration of offspring was shorter than those of the SS. In addition, fecundity was higher and developmental duration was longer in the RS reared on broad bean than in those reared-on eggplant. The results indicated that spinetoram resistance could change WFT host preference and that those changes might be associated with detoxification enzyme activities. Thus, it was hypothesized that adaptability of the RS to the less preferred host broad bean increased, whereas adaptability to the preferred host eggplant decreased.
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Affiliation(s)
- Dingyin Li
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guiyang 550025, Guizhou, P. R. China
| | - Junrui Zhi
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guiyang 550025, Guizhou, P. R. China
| | - Wenbo Yue
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guiyang 550025, Guizhou, P. R. China
| | - Tao Zhang
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guiyang 550025, Guizhou, P. R. China
| | - Li Liu
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Guiyang 550025, Guizhou, P. R. China
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Zhou Y, Zou X, Zhi J, Xie J, Jiang T. Fast Recognition of Lecanicillium spp., and Its Virulence Against Frankliniella occidentalis. Front Microbiol 2020; 11:561381. [PMID: 33193147 PMCID: PMC7642397 DOI: 10.3389/fmicb.2020.561381] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/01/2020] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Frankliniella occidentalis (Thysanoptera: Thripidae) is a highly rasping-sucking pest of numerous crops. The entomogenous fungi of Lecanicillium spp. are important pathogens of insect pests, and some species have been developed as commercial biopesticides. To explore Lecanicillium spp. resources in the development of more effective F. occidentalis controls, efficient barcode combinations for strain identification were screened from internal transcribed spacers (ITS), SSU, LSU, TEF, RPB1, and RPB2 genes. RESULTS Six genes were used to reconstruct Lecanicillium genus phylogeny. The results showed that ITS, TEF, RPB1, and RPB2 could be used to identify the strains. All phylogenetic trees reconstructed by free combination of these four genes exhibited almost the same topology. Bioassay studies of a purified conidial suspension further confirmed the infection of second-instar nymphs and adult female F. occidentalis by seven Lecanicillium strains. L. attenuatum strain GZUIFR-lun1405 was the most virulent, killing approximately 91.67% F. occidentalis adults and 76.67% nymphs after a 7-day exposure. L. attenuatum strain GZUIFR-lun1405 and L. cauligalbarum strain GZUIFR-ZHJ01 were selected to compare the fungal effects on the number of eggs laid by F. occidentalis. The number of F. occidentalis nymphs significantly decreased when F. occidentalis adults were treated with L. cauligalbarum strain GZUIFR-ZHJ01. CONCLUSIONS The combination of ITS and RPB1 could be used for fast recognition of Lecanicillium spp. This is the first report of the pathogenicity of L. attenuatum, L. cauligalbarum, L araneogenum, and L. aphanocladii against F. occidentalis. Additionally, L. cauligalbarum strain GZUIFR-ZHJ01 caused high F. occidentalis mortality and inhibited the fecundity of the pest.
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Affiliation(s)
- Yeming Zhou
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of Mountainous Region, Guiyang, China
| | - Xiao Zou
- Institute of Fungus Resources, Guizhou University, Guiyang, China
| | - Junrui Zhi
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of Mountainous Region, Guiyang, China
| | - Jiqin Xie
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of Mountainous Region, Guiyang, China
| | - Tao Jiang
- Institute of Entomology, Guizhou University, The Provincial Key Laboratory for Agricultural Pest Management of Mountainous Region, Guiyang, China
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Jackson CGCA, Deva S, Bayston K, McLaren B, Barlow P, Hung N, Clarke K, Segelov E, Chao TY, Dai MS, Yen HT, Cutler D, Kramer D, Zhi J, Chan WK, Kwan MFR, Hung CT. An international randomized cross-over bio-equivalence study of oral paclitaxel + HM30181 compared with weekly intravenous (IV) paclitaxel in patients with advanced solid tumours. Ann Oncol 2019. [DOI: 10.1093/annonc/mdz244.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Caimi P, Eder J, Jacobsen E, Jacobson C, LaCasce A, Shipp M, Chapuy B, Labriola-Tomphins E, Boisserie F, Passe S, Chesné E, Pierceall W, Zhi J, DeMario M, Vaishampayan U, Dowlati A, Shapiro G, Fisher D, Armand P. A PHASE 1 STUDY OF BET INHIBITION USING RG6146 IN RELAPSED/REFRACTORY (R/R) MYC-EXPRESSING DIFFUSE LARGE B CELL LYMPHOMA (DLBCL). Hematol Oncol 2017. [DOI: 10.1002/hon.2438_134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- P.F. Caimi
- Medicine - Hematology and Oncology; University Hospitals Seidman Cancer Center; Cleveland USA
| | - J.P. Eder
- Medicine / Section of Medical Oncology; Yale University Medical Center; New Haven USA
| | - E.D. Jacobsen
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - C.A. Jacobson
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - A.S. LaCasce
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - M.A. Shipp
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - B. Chapuy
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - E. Labriola-Tomphins
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | - F. Boisserie
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | - S. Passe
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | - E. Chesné
- Roche Innovation Center Basel; Roche Pharma Research and Early Development; Basel Switzerland
| | - W. Pierceall
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | - J. Zhi
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | - M. DeMario
- Roche Innovation Center New York; Roche Pharma Research and Early Development; New York USA
| | | | - A. Dowlati
- Medicine - Hematology and Oncology; University Hospitals Seidman Cancer Center; Cleveland USA
| | - G.I. Shapiro
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - D.C. Fisher
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
| | - P. Armand
- Division of Hematologic Neoplasia; Dana Farber Cancer Institute; Boston USA
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Razak A, Gore L, Britten C, Miller W, Uy G, Nichols G, Middleton S, Blotner S, Zhi J, Jukofsky L, Pierceall W, Higgins B, Chen L. A phase I study of the MDM2 antagonist RO6839921, a pegylated prodrug of idasanutlin, for intravenous (IV) administration in patients with advanced solid tumors. Eur J Cancer 2016. [DOI: 10.1016/s0959-8049(16)32645-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zhai S, Georgy A, Liang Z, Zhi J. Pharmacokinetic and Pharmacodynamic Drug Interaction Study of Piragliatin, a Glucokinase Activator, and Glyburide, a Sulfonylurea, in Type 2 Diabetic Patients. Clin Pharmacol Drug Dev 2016; 5:552-556. [PMID: 27274007 DOI: 10.1002/cpdd.276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/05/2016] [Accepted: 05/23/2016] [Indexed: 11/10/2022]
Abstract
A glucokinase activator and a sulfonylurea might be coprescribed to synergize treatment success for type 2 diabetes (T2D). This clinical pharmacology study was designed to investigate the potential glucose-lowering effect or pharmacodynamic (PD), pharmacokinetic (PK), and safety/tolerability interactions between piragliatin and glyburide in T2D patients already taking glyburide but not adequately controlled. This was an open-label, multiple-dose, 3-period, single-sequence crossover design: on days -1, 6, and 12, PD and PK samples were drawn with glyburide alone (period 0), piragliatin + glyburide (period 1), and piragliatin alone (period 2) treatments. The glucose-lowering effect, including fasting plasma glucose (FPG), of piragliatin was more pronounced when it was administered concomitantly with glyburide as compared to piragliatin or glyburide administered alone. However, this enhancement cannot be explained by a potential PK interaction between piragliatin and glyburide. Other than hypoglycemia, there were no clinically relevant safety findings. Thus, the enhanced PD effect warrants further investigation to define the optimal dose combination between glucokinase activators and sulfonylureas with regard to efficacy, safety, and tolerability.
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Affiliation(s)
- S Zhai
- Roche Innovation Center of New York, New York, NY, USA
| | - A Georgy
- Roche Innovation Center of New York, New York, NY, USA
| | - Z Liang
- Roche Innovation Center of New York, New York, NY, USA
| | - J Zhi
- Roche Innovation Center of New York, New York, NY, USA
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Xu C, Zhi J, Zhao W, Zhang L, Li D. Comparative analysis of the role of JNK signaling pathway in regulating cell proliferation and apoptosis of rat liver regeneration and rat acute hepatic failure. RUSS J GENET+ 2012. [DOI: 10.1134/s102279541208008x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Xu C, Zhi J, Zhao W, Zhang L, Li D. Comparative analysis of the role of JNK signaling pathway in regulating cell proliferation and apoptosis of rat liver regeneration and rat acute hepatic failure. Genetika 2012; 48:909-917. [PMID: 23035542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To compare the role of JNK signaling pathway in rat liver regeneration (LR) and in rat acute hepatic failure (AHF) occurrence at the gene transcription level, Rat Genome 230 2.0 array was used to detect the gene expression profiles of the two processes, and bioinformatics and systems biology methods were applied to analyze the physiological activities uncovered by their gene expression profiles in this study. The results showed that 240 genes were included in the array above, though there were 302 genes related to forty two paths of JNK signaling pathway. Array detection results demonstrated that 52 genes were significantly expressed during LR, 20 genes in AHF occurrence, and 15 genes in both of above two processes. Synergy values of these genes were calculated using a mathematical model established by our lab, which revealed the following. The cell proliferation-promoting effects of paths 1, 16 and paths 1-17 of JNK signaling pathway were stronger than the control at 6-12 h and 72 h of LR, respectively, while the cell proliferation-promoting effects of paths 1-17 and the cell proliferation-inhibiting effects of path 34-35 were weaker at 6h of AHF occurrence. The cell apoptosis-promoting effects of paths 22-23 were much stronger at 6, 12 and 72 h of LR and at 12, 24 h of AHF occurrence. In conclusion, thirty eight paths of JNK signaling pathway regulate cell proliferation and apoptosis in both LR and AHF occurrence.
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Affiliation(s)
- C Xu
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China.
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Ray-Coquard IL, Blay J, Italiano A, Le Cesne A, Penel N, Zhi J, Beryozkina A, Heil F, Rueger R, Nichols GL, Bui Nguyen B. Neoadjuvant MDM2 antagonist RG7112 for well-differentiated and dedifferentiated liposarcomas (WD/DD LPS): A pharmacodynamic (PD) biomarker study. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.10007b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Beryozkina A, Nichols GL, Reckner M, Vassilev LT, Rueger R, Jukofsky L, Middleton S, Andreeff M, Padmanabhan S, Strair R, Delioukina ML, Maslak PG, Hillmen P, Kurzrock R, Gore L, Patnaik A, Maki RG, Schwartz GK, Wagner AJ, Zhi J. Pharmacokinetics (PK) and pharmacodynamics (PD) of RG7112, an oral murine double minute 2 (MDM2) antagonist, in patients with leukemias and solid tumors. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.3039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Xu C, Wang G, Zhang L, Chang C, Zhi J, Hao Y. Correlation between liver cancer occurrence and gene expression profiles in rat liver tissue. Genet Mol Res 2011; 10:3480-513. [DOI: 10.4238/2011.december.14.3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Attard G, Kitzen J, Blagden SP, Fong PC, Pronk LC, Zhi J, Zugmaier G, Verweij J, de Bono JS, de Jonge M. A phase Ib study of pertuzumab, a recombinant humanised antibody to HER2, and docetaxel in patients with advanced solid tumours. Br J Cancer 2007; 97:1338-43. [PMID: 18000498 PMCID: PMC2360237 DOI: 10.1038/sj.bjc.6604043] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Pertuzumab represents the first in a new class of targeted therapeutics known as HER dimerisation inhibitors. We conducted a phase Ib study to determine the maximum-tolerated dose, the dose limiting toxicities (DLT), and pharmacokinetic (PK) interaction of docetaxel when administered in combination with pertuzumab. Initially, two dose levels of docetaxel (60 and 75 mg m−2) were explored in combination with a fixed dose of 1050 mg of pertuzumab; then two dose levels of docetaxel (75 and 100 mg m−2) were explored in combination following a fixed dose of 420 mg of pertuzumab with a loading dose of 840 mg. Both drugs were administered intravenously every 3 weeks. The latter dose of pertuzumab was allowed after an amendment to the original protocol when phase II data suggesting no difference in toxicity or activity between the 2 doses became available. Two patients out of two treated at docetaxel 75 mg m−2 in combination with pertuzumab 1050 mg suffered DLT (grade 3 diarrhoea and grade 4 febrile neutropaenia). Two out of five patients treated at docetaxel 100 mg m−2 in combination with pertuzumab 420 mg with a loading dose of 840 mg suffered DLT (grade 3 fatigue and grade 4 febrile neutropaenia). Stable disease was observed at four cycles in more than half of the patients treated and a confirmed radiological partial response with a >50% decline in PSA in a patient with hormone refractory prostate cancer were observed. There were no pharmacokinetic drug–drug interactions. The recommended phase II dose of this combination was docetaxel 75 mg m−2 and 420 mg pertuzumab following a loading dose of 840 mg.
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Affiliation(s)
- G Attard
- Drug Development Unit, The Royal Marsden NHS Foundation Trust, Sutton, UK
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15
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Powers JF, Evinger MJ, Zhi J, Picard KL, Tischler AS. Pheochromocytomas in Nf1 knockout mice express a neural progenitor gene expression profile. Neuroscience 2007; 147:928-37. [PMID: 17582688 DOI: 10.1016/j.neuroscience.2007.05.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 05/08/2007] [Accepted: 05/09/2007] [Indexed: 11/23/2022]
Abstract
Pheochromocytomas are adrenal medullary tumors that typically occur in adult patients, with increased frequency in multiple endocrine neoplasia type 2, von Hippel-Lindau disease, familial paraganglioma syndromes and neurofibromatosis type 1 (NF1). Pheochromocytomas arise in adult mice with a heterozygous knockout mutation of exon 31 of the murine Nf1 gene, providing a mouse model for pheochromocytoma development in NF1. We performed a microarray-based gene expression profiling study comparing mouse pheochromocytoma tissue to normal adult mouse adrenal medulla to develop a basis for studying the pathobiology of these tumors. The findings demonstrate that pheochromocytomas from adult neurofibromatosis knockout mice express multiple developmentally regulated genes involved in early development of both the CNS and peripheral nervous system. One of the most highly overexpressed genes is receptor tyrosine kinase Ret, which is known to be transiently expressed in the developing adrenal gland, down-regulated in adult adrenals and often overexpressed in human pheochromocytomas. Real-time polymerase chain reaction validated the microarray results and immunoblots confirmed the overexpression of Ret protein. Other highly expressed validated genes include Sox9, which is a neural crest determinant, and Hey 1, which helps to maintain the progenitor status of neural precursors. The findings are consistent with the recently proposed concept that persistent neural progenitors might give rise to pheochromocytomas in adult mouse adrenals and suggest that events predisposing to tumor development might occur before formation of the adrenal medulla or migration of cells from the neural crest. However, the competing possibility that developmentally regulated neural genes arise secondarily to neoplastic transformation cannot be ruled out. In either case, the unique profile of gene expression opens the mouse pheochromocytoma model to new applications pertinent to neural stem cells and suggests potential new targets for treatment of pheochromocytomas or eradication of their precursors.
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Affiliation(s)
- J F Powers
- Department of Pathology, Tufts New England Medical Center, 750 Washington Street, Boston, MA 02111, USA.
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Attard G, Kitzen JJ, de Bono J, Verweij J, Pronk L, Zhi J, Blagden SP, Reade SE, Zugmaier G, de Jonge MJ. A phase Ib study of pertuzumab (P), a recombinant humanized antibody to HER2, and docetaxel (D) in patients (pts) with advanced solid tumors. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.3166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- G. Attard
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - J. J. Kitzen
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - J. de Bono
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - J. Verweij
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - L. Pronk
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - J. Zhi
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - S. P. Blagden
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - S. E. Reade
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - G. Zugmaier
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - M. J. de Jonge
- The Royal Marsden Hosp, Sutton, United Kingdom; Erasmus Univ Medcl Ctr, Rotterdam, The Netherlands; F. Hoffmann-La Roche Ltd, Basel, Switzerland
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Zhi J, Moore R, Kanitra L, Mulligan T. Pharmacokinetic Evaluation of the Possible Interaction between Selected Concomitant Medications and Orlistat at Steady State in Healthy Subjects. J Clin Pharmacol 2002. [DOI: 10.1177/009127002401102939] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Zhi J, Sommerfeldt DW, Rubin CT, Hadjiargyrou M. Differential expression of neuroleukin in osseous tissues and its involvement in mineralization during osteoblast differentiation. J Bone Miner Res 2001; 16:1994-2004. [PMID: 11697795 DOI: 10.1359/jbmr.2001.16.11.1994] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Osteoblast differentiation is a multistep process that involves critical spatial and temporal regulation of cellular processes marked by the presence of a large number of differentially expressed molecules. To identify key functional molecules, we used differential messenger RNA (mRNA) display and compared RNA populations isolated from the defined transition phases (proliferation, matrix formation, and mineralization) of the MC3T3-E1 osteoblast-like cell line. Using this approach, a complementary DNA (cDNA) fragment was isolated and identified as neuroleukin (NLK), a multifunctional cytokine also known as autocrine motility factor (AMF), phosphoglucose isomerase (PGI; phosphohexose isomerase [PHI]), and maturation factor (MF). Northern analysis showed NLK temporal expression during MC3T3-E1 cell differentiation with a 3.5-fold increase during matrix formation and mineralization. Immunocytochemical studies revealed the presence of NLK in MC3T3-E1 cells as well as in the surrounding matrix, consistent with a secreted molecule. In contrast, the NLK receptor protein was detected primarily on the cell membrane. In subsequent studies, a high level of NLK expression was identified in osteoblasts and superficial articular chondrocytes in bone of 1-, 4-, and 8-month-old normal mice, as well as in fibroblasts, proliferating chondrocytes, and osteoblasts within a fracture callus. However, NLK was not evident in hypertrophic chondrocytes or osteocytes. In addition, treatment of MC3T3 cells with 6-phosphogluconic acid (6PGA; a NLK inhibitor) resulted in diminishing alkaline phosphatase (ALP) activity and mineralization in MC3T3-E1 cells, especially during the matrix formation stage of differentiating cells. Taken together, these data show specific expression of NLK in discrete populations of bone and cartilage cells and suggest a possible role for this secreted protein in bone development and regeneration.
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Affiliation(s)
- J Zhi
- Department of Biomedical Engineering, State University of New York at Stony Brook, 11794-2580, USA
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19
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Trouillot TE, Pace DG, McKinley C, Cockey L, Zhi J, Häeussler J, Guerciolini R, Showalter R, Everson GT. Orlistat maintains biliary lipid composition and hepatobiliary function in obese subjects undergoing moderate weight loss. Am J Gastroenterol 2001; 96:1888-94. [PMID: 11421247 DOI: 10.1111/j.1572-0241.2001.03783.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Orlistat, an intestinal lipase inhibitor, has recently been approved by the US Food and Drug Administration for treatment of obesity. The effects of orlistat on hepatobiliary function have not been previously defined. A 4 wk study was performed involving modest weight loss in obese subjects to observe any short-term hepatobiliary responses that occur after initiating treatment with orlistat and a hypocaloric diet. METHODS A total of 23 obese (BMI 30-41 kg/m2) subjects were randomized to a double blind t.i.d. treatment with 120 mg of orlistat or a placebo in conjunction with a hypocaloric diet (1200-1500 kcal/day). The study was designed to achieve similar modest weight loss in both groups in order to be able to directly assess the effects of orlistat. Cholesterol saturation, bile composition, and gallbladder motility were measured. RESULTS At the end of the treatment period, mean weight loss of 3.8 kg was achieved in the orlistat group (vs 2.3 kg with placebo, p = NS). Total bile acid concentration decreased significantly with placebo (-18.57 +/- 6.99 mmol/L; 95% CI = -32.26 to -4.87), but not with orlistat. Biliary phospholipid concentration decreased significantly with placebo (-4.38 +/- 1.91 mmol/L; 95% CI = -8.13 to -0.64) but not with orlistat. Mean changes from the baseline in cholesterol saturation index and gallbladder motility were similar in both groups. Microscopy of bile failed to reveal cholesterol microcrystals before or after treatment in either group. CONCLUSIONS Our findings indicate a primary initial effect of weight loss is a reduction in biliary bile acids and phospholipids. Orlistat blocks these adverse changes in biliary lipid composition and maintains hepatobiliary function. We speculate that the risk of formation of gallstones during weight loss may actually be lowered with orlistat.
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Affiliation(s)
- T E Trouillot
- University of Colorado Health Sciences Center, Denver 80262, USA
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20
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Shepard TY, Jensen DR, Blotner S, Zhi J, Guerciolini R, Pace D, Eckel RH. Orlistat fails to alter postprandial plasma lipid excursions or plasma lipases in normal-weight male volunteers. Int J Obes (Lond) 2000; 24:187-94. [PMID: 10702769 DOI: 10.1038/sj.ijo.0801105] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES After 10 d of orlistat administration (120 mg three times/day), the primary objective was to determine the drug's effect on postprandial plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities on day 10 after an oral fat-load. The secondary objectives were to determine the effects of orlistat on 12 h postprandial measures of: (1) preheparin HTGL and LPL; and (2) serum triglycerides, very-low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and free fatty acids. METHODS Twenty-four normal-weight, healthy male volunteers were randomized to either 120 mg orlistat (n=12) or placebo (n=12) three times a day with meals for 10 d. Preheparin LPL and HTGL activities and LPL specific activity were measured in the fasted state on days 1, 5, and 10. On days 5 and 10 the study medication (orlistat or placebo) was taken at the beginning of a fat-rich breakfast and serum lipid and lipoprotein levels monitored for 12 h postprandially. On day 10, 15 min postheparin HTGL activity was measured 8 h after the fat-rich breakfast. RESULTS No differences were found between groups in fasting levels of preheparin LPL or HTGL activity or in LPL-specific activity on days 1, 5 and 10. No difference was found between the two treatment groups in postheparin HTGL activity 8 h after the fat-rich breakfast. Also, no differences were found between the two groups in plasma triglycerides or lipoproteins. CONCLUSION The results indicate that the oral administration of orlistat (120 mg t. i.d.) does not significantly alter plasma triglycerides or lipoproteins, and that the inhibitory effect of orlistat on lipases is limited to the gastrointestinal tract and is not manifested systemically.
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Affiliation(s)
- T Y Shepard
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Health Sciences Center, 4200 E. 9th Avenue, Denver, CO 80262, USA
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Abstract
The dadAX operon is expressed by multiple promoters that are repressed by leucine-responsive regulatory protein (Lrp) and activated by cyclic AMP-CRP. In previous work, we found that alanine or leucine acted as inducers to antagonize Lrp repression of the three major promoters directly. Here, we identify 11 Lrp binding sites located within 350 bp of dad DNA. A mutational analysis, coupled with in vivo and in vitro transcription experiments, indicated that Lrp sites that overlap the dad promoters were involved in repression. In contrast, sites upstream of the promoters did not appear to be necessary for repression, but were required for activation by Lrp plus alanine or leucine of one of the major dad promoters, P2. This activation by alanine or leucine was not simply relief of repression, as P2 transcription from a constitutive template was increased fivefold compared with the basal level of transcription found in the absence of Lrp and the co-activator cyclic AMP-CRP. Alanine or leucine decreased the affinity of Lrp to repressor sites, while having little or no effect on the binding of Lrp to activator sites. This differential effect of alanine and leucine on Lrp binding helps to explain how these modifiers influence both repression and activation of the dad operon.
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Affiliation(s)
- J Zhi
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook 11794, USA
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22
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Abstract
Orlistat, a lipase inhibitor, acts locally in the gastrointestinal tract; its systemic exposure is not required for its efficacy. However, knowledge of the extent of its systemic exposure is important for its safe use in obese patients, the intended target population. Pharmacokinetic screening in obese patients was carried out by monitoring plasma concentrations of unchanged orlistat and its metabolites in five key double-blind, placebo-controlled phase II/III studies. Results of these studies involving the monitoring of plasma samples indicate that detection of intact orlistat in plasma was sporadic, and measurable concentrations were low (< 10 ng/mL or 0.02 microM) without evidence of accumulation, which is consistent with minimal absorption. It is concluded that systemic exposure of orlistat is negligible; at a clinically efficacious dose level, orlistat is unlikely to produce systemic lipase inhibition.
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Affiliation(s)
- J Zhi
- Hoffmann-La Roche, Inc., Department of Clinical Pharmacology, Nutley, NJ 07110-1199, USA
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23
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Melia AT, Zhi J, Zelasko R, Hartmann D, Güzelhan C, Guerciolini R, Odink J. The interaction of the lipase inhibitor orlistat with ethanol in healthy volunteers. Eur J Clin Pharmacol 1998; 54:773-7. [PMID: 9923583 DOI: 10.1007/s002280050550] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The primary objective was to investigate the possible interference of ethanol on the orlistat effect on inhibition of dietary fat absorption and the possible interference of orlistat on the pharmacokinetics of ethanol. Secondary objectives were to assess the tolerability during concomitant dosing of orlistat and ethanol and to determine the ethanol effect on plasma levels of orlistat. METHODS This was a double-blind, placebo-controlled, parallel, randomized study performed in 30 (three parallel groups of ten subjects each) healthy normal weight male subjects between the ages of 20 and 30 years. A 5-day run-in period to accustom subjects to a standardized diet of 2500 kcal/day (30% fat) and to establish baseline fecal fat excretion was followed by a 6-day treatment period. Subjects were randomly assigned to one of three treatment groups (A = orlistat 120 mg t.i.d. and ethanol placebo, B = orlistat 120 mg t.i.d. and 40 g ethanol qd on days -1 and 6, and 40 g bid on days 1-5, and C = orlistat placebo tid and 40 g ethanol qd on days -1 and 6, and 40 g b.i.d. on days 1 5). Serial blood samples were collected for determination of ethanol serum concentrations at specified times over 5 h after each dose of ethanol on days -1 and 6, and for determination of orlistat plasma concentrations on days 1, 3, 5, and 6. Feces were collected quantitatively on days -5 through 8 for analysis of fecal fat. RESULTS The means of baseline-corrected fecal fat excretion values were comparable: 23.7 g for group A (orlistat) and 22.7 g for group B (orlistat and ethanol). No significant difference was found regarding ethanol pharmacokinetic parameters between treatments with orlistat and placebo. No apparent differences existed between the number of plasma samples with measurable orlistat concentrations in groups A and B. CONCLUSION Concomitant ingestion of social amounts of ethanol did not alter the inhibitory effect of orlistat on dietary fat absorption during short-term treatment (6 days) with orlistat. Short-term treatment with orlistat had no significant influence on ethanol pharmacokinetics.
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Affiliation(s)
- A T Melia
- Department of Clinical Pharmacology, Hoffmann-La Roche Inc., Nutley, NJ 07110-1199, USA
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Zhang W, Zhi J, Guo W, Zhao R, Jin G. [Effects of l-stepholidine on the peripheral vascular dopamine DA1 and DA2 receptor subtypes]. Yao Xue Xue Bao 1998; 33:721-6. [PMID: 12016922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The effects of l-stepholidine(l-SPD) on peripheral vascular dopamine DA1 and DA2 receptors were studied using isolated vascular rings in rabbits. It was shown that (1) l-SPD(0.1-10 mumol.L-1) shifted the dose-response curves to the right in a nonparallel fashion and decreased the maximal response (Emax) of both the fenoldopam(FODA, a selective DA1 agonist)-induced and the propyl-buty-dopamine(PBDA, a selective DA2 agonist)-induced vasorelaxation showing a non-competitive antagonistic action. The pD2 values of l-SPD for FODA in the renal, pulmonary and mesenteric arteries were 5.43, 5.48 and 5.58, respectively. The pD2 values for PBDA in the mesenteric and femoral arteries were 5.35 and 5.89, respectively. The potencies of its antagonistic action were comparable to SCH23390, a selective DA1 antagonist, and to domperidone, a selective DA2 antagonist. (2) l-SPD(0.1-100 mumol.L-1) per se was also found to induce slight but dose-related vasorelaxations in the renal and pulmonary arteries displaying its DA1 agonistic activity. Its pD2 values were 4.98 and 5.02, respectively. However, its Emax were considerably smaller than that of FODA. These results suggest that l-SPD is a mixed peripheral DA1 and DA2 receptor antagonists and weak DA1 receptor agonist with pharmacological property of dual action.
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Affiliation(s)
- W Zhang
- Department of Physiology, Shanxi Medical University, Taiyuan 030001
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25
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Kim J, Zhi J, Satoh H, Koss-Twardy SG, Passe SM, Patel IH, Pazdur R. Pharmacokinetics of recombinant human interferon-alpha 2a combined with 5-fluorouracil in patients with advanced colorectal carcinoma. Anticancer Drugs 1998; 9:689-96. [PMID: 9823427 DOI: 10.1097/00001813-199809000-00004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We evaluated the pharmacokinetics of 5-fluorouracil (5-FU) combined with recombinant human interferon (IFN)-alpha 2a in 10 previously untreated patients with advanced colorectal carcinoma. 5-FU was administered as a continuous i.v. infusion, 750 mg/m2/day for 5 days during week 1. One s.c. injection of IFN-alpha 2a, 9 x 10(6) IU, was administered during week 2. Beginning with week 3, a continuous i.v. infusion of 5-FU 750 mg/m2/day for 5 days was administered in combination with IFN-alpha 2a, 9 x 10(6) IU s.c. three times per week. The combination of 5-FU and IFN-alpha 2a was continued every other week until either 3 months after complete remission or tumor progression. No grade 4 toxicity was observed. Granulocytopenia (two patients), leukopenia (one patient), thrombocytopenia (one patient), stomatitis (two patients), fatigue (one patient) and hand-foot syndrome (one patient) were the major (grade 3) toxic reactions encountered. Overall, one complete and six partial responses were noted. The results of the paired t-test showed no statistically significant differences between the means of the two treatments, 5-FU and 5-FU plus IFN-alpha 2a, with respect to the steady-state plasma concentration, area under the concentration-time curve, total body clearance, or steady-state volume of distribution of 5-FU, or the serum concentration of IFN. We conclude that 5-FU and IFN-alpha 2a do not interact pharmacokinetically at the doses and schedules in the regimen studied.
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Affiliation(s)
- J Kim
- Division of Medicine, University of Texas MD Anderson Cancer Center, Houston 77030, USA
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26
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Zhi J, Mathew E, Freundlich M. In vitro and in vivo characterization of three major dadAX promoters in Escherichia coli that are regulated by cyclic AMP-CRP and Lrp. Mol Gen Genet 1998; 258:442-7. [PMID: 9648752 DOI: 10.1007/s004380050754] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have shown previously that the dadAX operon of Escherichia coli expresses multiple transcripts, which are repressed by leucine-responsive regulatory protein (Lrp). Here we used site-directed mutagenesis and in vitro and in vivo transcription assays to show that each of the three major dad transcripts requires a specific promoter. These promoters, P1-P3, overlap and are positively regulated in vivo by cyclic AMP-CRP. DNase I footprinting experiments localized two CRP binding sites in this region: CRP1, which is positioned upstream of P1-P3, and CRP2, which is located within the promoters. Site-directed mutagenesis of each site provided evidence that CRP1 is necessary for the effects of cyclic AMP-CRP on dad expression in vivo and in vitro, and that CRP2 probably plays little or no role in this process.
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Affiliation(s)
- J Zhi
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, 11794, USA
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27
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Abstract
Expression of the degradative D-amino acid dehydrogenase (dad) operon is known to be increased when Escherichia coli is grown in the presence of D- or L-alanine. Alanine is thought to act as an inducer to block the action of a postulated repressor. This operon is also believed to be regulated by catabolite repression. We have used in vivo and in vitro experiments that show that the dad repressor is the leucine-responsive regulatory protein (Lrp). dad expression in a dad-lacZ operon fusion strain was increased four- to sevenfold when cells were grown in minimal medium containing alanine or leucine. A strain lacking Lrp had high-level constitutive dad expression. Gel retardation and footprinting studies revealed that Lrp binds in vitro to multiple sites over a large area in the dad promoter region. This binding was reduced by alanine or leucine. In vitro transcription assays, using a plasmid template and primer extension analysis, identified three major dad transcripts (Tr1, Tr2, and Tr3). The formation of these transcripts was differentially regulated by cyclic AMP-cyclic AMP receptor protein complex, and each was strongly repressed by Lrp. Alanine or leucine completely (for Tr1 and Tr2) or partially (for Tr3) reversed Lrp inhibition. Site-directed mutagenesis of an Lrp binding site strongly reduced Lrp binding and prevented Lrp repression of dad transcription in vivo and in vitro. Taken together, these results strongly suggest that Lrp and alanine or leucine act directly to repress and induce, respectively, transcription of the dad operon.
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Affiliation(s)
- E Mathew
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook 11794, USA
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28
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Zhi J, Melia AT, Funk C, Viger-Chougnet A, Hopfgartner G, Lausecker B, Wang K, Fulton JS, Gabriel L, Mulligan TE. Metabolic profiles of minimally absorbed orlistat in obese/overweight volunteers. J Clin Pharmacol 1996; 36:1006-11. [PMID: 8973989 DOI: 10.1177/009127009603601104] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To determine the metabolic profile of minimally absorbed orlistat in obese/overweight patients, an open-label, single-dose study was performed in eight obese/overweight volunteers between 23 and 68 years of age. Each subject received a single oral dose of 360 mg orlistat containing approximately 400 muCi of 14C-labeled orlistat. Serial blood samples were collected at specified times over 10 hours after administration of orlistat for determination of total radioactivity, unchanged orlistat, and major metabolites in the plasma. Urine samples were collected over 24 hours and analyzed to evaluate the urinary recovery of total radioactivity and the profile of orlistat metabolites in the urine. In addition, all fecal samples were collected and analyzed for total radioactivity. Urinary and fecal recovery of the administered dose of total radioactivity were 1.13 +/- 0.50% (24-hour data only) and 96.4 +/- 18.1% (n = 7), respectively. Maximum observed concentration (Cmax) and time to Cmax (tmax) values of plasma total radioactivity were 150 +/- 51 ng.eq/mL and 6.8 +/- 1.5 hrs, respectively. All these parameters obtained in obese/ overweight subjects were similar to those reported previously in healthy subjects. On the basis of the area under the concentration-time curve from 0 to 10 hours (AUC0-10), two major metabolites comprise a total of approximately 42% of the total radioactivity in plasma. The primary metabolite (M1) has a short half-life (approximately 2 hours), whereas the secondary metabolite (M3) disappeared at a slower rate. No strikingly apparent difference in the urinary metabolic profile was observed between two gender groups. It is concluded that the disposition of orlistat appears to be similar between normal and obese/overweight subjects. Of the minimal fraction of the dose that was absorbed systemically, the presence of two major metabolites accounts for approximately 42%.
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Affiliation(s)
- J Zhi
- Hoffmann-La Roche, Inc. Nutley, New Jersey 07110-1199, USA
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Melia AT, Koss-Twardy SG, Zhi J. The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. J Clin Pharmacol 1996; 36:647-53. [PMID: 8844448 DOI: 10.1002/j.1552-4604.1996.tb04230.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers (between 20 and 44 years of age) to assess the effect of orlistat, a gastrointestinal lipase inhibitor that reduces dietary fat absorption and is being developed for weight control in obesity, on the absorption of vitamins A and E. Each participant received a single oral dose of 25,000 IU vitamin A followed 24 hours later by a single oral dose of 400 IU vitamin E on two separate occasions: during oral administration of 120 mg orlistat or placebo three times daily for 9 days. The two treatments were separated by a washout period of at least 2 weeks. Serial blood samples for pharmacokinetic analysis were collected at specified times over 24 hours after each dose of vitamin A for determination of serum concentrations of retinol, and over a period of 5 days after each dose of vitamin E for determination of serum concentrations of alpha-tocopherol, total cholesterol, and triglycerides. Orlistat significantly reduced the absorption of vitamin E (approximately 43% according to maximum concentration and approximately 60% according to area under the concentration-time curve), but not that of vitamin A, at the dose levels studied. The results of this study will aid in the implementation of a vitamin supplementation strategy, should vitamin deficiency occur in patients undergoing orlistat therapy.
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Affiliation(s)
- A T Melia
- Hoffmann-La Roche Inc., Nutley, New Jersey 07110-1199, USA
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Abstract
To assess the effect of an orlistat-induced reduction in dietary fat absorption on the pharmacokinetics of phenytoin, a third-party blind, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each participant received single 300-mg oral doses of phenytoin administered on the fourth day of treatment with 120 mg orlistat (treatment A) or placebo (treatment B) three times a day for 7 days. The two treatments were separated by a 2-week washout period. Serial blood samples were collected before and up to 96 hours after each dose of phenytoin to determine serum concentrations of phenytoin. The 90% confidence intervals (CI) for the ratio of geometric least-squares means for maximum concentration (Cmax) and area under the concentration-time curve (AUC) and for the difference of arithmetic least-squares means for time of maximum concentration (tmax) and elimination rate constant (lambda z) showed the two treatments of phenytoin to be equal by analysis of variance. An approximately 30% reduction in dietary fat absorption induced by orlistat administered at doses of 120 mg three times daily did not significantly alter the pharmacokinetics of a single 300-mg oral dose of phenytoin in healthy volunteers.
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Affiliation(s)
- A T Melia
- Hoffmann-La Roche, Inc., Nutley, New Jersey 07110-1199, USA
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Zhi J, Melia AT, Guerciolini R, Koss-Twardy SG, Passe SM, Rakhit A, Sadowski JA. The effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers. J Clin Pharmacol 1996; 36:659-66. [PMID: 8844450 DOI: 10.1002/j.1552-4604.1996.tb04232.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To assess the effect of orlistat on the pharmacokinetics and pharmacodynamics of warfarin, a third-party blind, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each participant received single 30-mg oral doses of racemic warfarin sodium (Coumadin; DuPont Pharma, Wilmington, DE) administered on the eleventh day of treatment with 120 mg orlistat (treatment A) and placebo (treatment B) three times a day for 16 days; the two treatments were separated by a 3-week washout period. Serial blood samples were collected before and at appropriate intervals after each dose of warfarin to determine plasma concentrations of R-warfarin and S-warfarin and blood prothrombin time (PT) and plasma Factor VII concentration. In addition, serum concentrations of vitamin K1 and its epoxide and of osteocalcin and its undercarboxylated form were measured before breakfast on days -7, 1, 4, 6, and 10. Equivalent results between treatments with orlistat and placebo were found with regard to all pharmacokinetic parameters of R- and S-warfarin (except for time to maximum concentration of R-warfarin). Pharmacodynamic parameters of warfarin (PT and Factor VII) and vitamin K nutritional status parameters (ratios of vitamin K1 to vitamin K1 epoxide and undercarboxylated osteocalcin to osteocalcin) also were unaltered by orlistat. Orlistat administered at doses of 120 mg three times daily did not significantly alter the pharmacokinetics and pharmacodynamics of a single 30-mg oral dose of warfarin in healthy volunteers.
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Affiliation(s)
- J Zhi
- Department of Clinical Pharmacology, Hoffmann-La Roche, Inc., Nutley, NJ 07110-1199, USA
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Melia AT, Mulligan TE, Zhi J. Lack of effect of orlistat on the bioavailability of a single dose of nifedipine extended-release tablets (Procardia XL) in healthy volunteers. J Clin Pharmacol 1996; 36:352-5. [PMID: 8728349 DOI: 10.1002/j.1552-4604.1996.tb04211.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Orlistat, a lipase inhibitor, reduces dietary fat absorption, and thus could potentially alter the absorption of some concomitantly administered drugs, such as the nifedipine gastrointestinal therapeutic system (GITS). To assess the effect of orlistat on the bioavailability of nifedipine GITS, a third party-blind, placebo-controlled, randomized, two-way crossover study was performed in 18 healthy volunteers. Each participant received single 60-mg oral doses of nifedipine GITS (Procardia XL; Pfizer Labs, New York, NY) on the fourth day of treatment with 120 mg of orlistat or placebo three times a day for 6 days. The two treatments were separated by a washout period of at least 1 week. Serial blood samples were collected before and at appropriate intervals after each nifedipine dose to determine plasma concentrations of nifedipine. The 90% confidence intervals for the ratio of geometric least-square means for maximum concentration (C(max)) and area under the concentration-time curve (AUCo-t) and for the difference of arithmetic least-square means for time to maximum concentration (t(max)) indicate that the bioavailability of nifedipine was not altered by treatment with orlistat. Therapeutic doses of 120 mg of orlistat three times daily do not significantly alter the bioavailability of a single 60-mg oral dose of nifedipine GITS in healthy volunteers.
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Affiliation(s)
- A T Melia
- Hoffmann-La Roche, Inc., Nutley, New Jersey 07110-1199, USA
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Zhi J, Melia AT, Koss-Twardy SG, Arora S, Patel IH. The effect of orlistat, an inhibitor of dietary fat absorption, on the pharmacokinetics of beta-carotene in healthy volunteers. J Clin Pharmacol 1996; 36:152-9. [PMID: 8852391 DOI: 10.1002/j.1552-4604.1996.tb04180.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To assess the influence of orlistat, a lipase inhibitor, on the absorption of beta-carotene, an open-label, parallel, placebo-controlled, randomized, two-way crossover study was performed in 48 healthy volunteers between the ages of 19 and 58 years. Each subject received a single oral dose of 0, 30, 60, or 120 mg beta-carotene (12 subjects per dose level) on the fourth day of treatment with orlistat (120 mg) or placebo 3 times a day for 6 days. The treatments were separated by a washout period of at least 5 weeks. Serial blood samples were collected before and at appropriate intervals after administration of beta-carotene to determine plasma concentrations of unchanged beta-carotene. Short-term (3 to 6 days) treatment with orlistat did not alter endogenous profiles of beta-carotene in plasma. When beta-carotene was given during orlistat treatment, its absorption was reduced by approximately one-third. This reduction was consistent for all three dose levels of beta-carotene studied; however, the results for the 30-mg dose level were subject to greater variability, particularly for area under the concentration-time curve (AUC). It was concluded that two thirds of a supplemental dose of beta-carotene will be absorbed during orlistat treatment; this may be sufficient to achieve physiologic levels of beta-carotene with an appropriate dose of beta-carotene, should supplementation be needed in obese patients who have developed beta-carotene deficiency during therapy with orlistat.
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Affiliation(s)
- J Zhi
- Hoffmann-La Roche, Inc., Nutley, New Jersey 07110-1199, USA
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Affiliation(s)
- J Zhi
- Department of Clinical Pharmacokinetics, Hoffmann-La Roche, Inc., Nutley, NJ 07110-1199, USA
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Abstract
Orlistat, a lipase inhibitor, acts locally in the gastrointestinal tract. Systemic absorption is not required for its efficacy, but knowledge of the extent of its systemic absorption is important for its safe use in obese patients, the intended target population. Pharmacokinetic screening was carried out by monitoring plasma concentrations of unchanged orlistat in 25 phase 1 studies (including two mass balance studies) in normal and obese healthy volunteers. The results of these studies indicate an extremely low degree of systemic absorption for orlistat when administered with a hypocaloric, well-balanced diet with 20% to 30% of calories derived from fat (50-80 gm). To further characterize the pharmacokinetics and excretion pathways of orlistat, two mass balance studies using 14C-labeled orlistat were conducted. After oral dosing of radiolabeled orlistat with a fatty meal (28-30 gm fat), almost the entire dose was recovered from fecal samples; little was found in plasma and urine. It is concluded that systemic absorption of orlistat is negligible; at a clinically efficacious dose level, orlistat is unlikely to produce systemic lipase inhibition.
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Affiliation(s)
- J Zhi
- Hoffmann-La Roche, Inc., Nutley, New Jersey 07110-1199, USA
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Melia AT, Zhi J, Koss-Twardy SG, Min BH, Smith BL, Freundlich NL, Arora S, Passe SM. The influence of reduced dietary fat absorption induced by orlistat on the pharmacokinetics of digoxin in healthy volunteers. J Clin Pharmacol 1995; 35:840-3. [PMID: 8522642 DOI: 10.1002/j.1552-4604.1995.tb04128.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To assess the influence of an orlistat-induced reduction in dietary fat absorption on the pharmacokinetics of digoxin, an open-label, placebo-controlled, randomized, two-way crossover study was performed in 12 healthy volunteers. Each subject received single 0.4-mg doses of digoxin (soft gelatin capsules) administered orally on the fourth day of orlistat (120 mg three times daily for 6 days) and placebo (three times daily for 6 days) treatment, separated by at least an 11-day washout period. Serial blood samples were collected before and at appropriate intervals after each digoxin dose to determine plasma concentrations of unchanged digoxin. The 90% confidence intervals for the ratio of geometric least-squares means (for Cmax, AUC0-48, AUC0-t, and AUC) and for the difference of arithmetic least-squares means (for tmax and lambda z) indicate that the pharmacokinetics of digoxin was not altered by treatment with orlistat. This results suggests that a approximately 30% reduction in dietary fat absorption will not change the efficacy of digoxin in cardiac patients.
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Affiliation(s)
- A T Melia
- Hoffmann-La Roche Inc., Nutley, New Jersey 07110-1199, USA
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Zhi J, Melia AT, Koss-Twardy SG, Min B, Guerciolini R, Freundlich NL, Milla G, Patel IH. The influence of orlistat on the pharmacokinetics and pharmacodynamics of glyburide in healthy volunteers. J Clin Pharmacol 1995; 35:521-5. [PMID: 7657854 DOI: 10.1002/j.1552-4604.1995.tb04098.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To assess the influence of orlistat on the pharmacokinetics and pharmacodynamics (the blood glucose-lowering effect) of glyburide, an open-label, placebo-controlled, randomized, two-way crossover study was done in 12 healthy male volunteers. Each subject received single 5-mg oral doses of glyburide (Micronase; The Upjohn Company, Kalamazoo, MI) on the fifth day of treatment with placebo (treatment A) and 80-mg orlistat (treatment B) three times a day for 4 1/3 days; the two treatments were separated by a five-day washout period. Serial blood samples were collected before and at appropriate intervals after each glyburide dose to determine plasma concentrations and blood glucose levels. Values of Cmax and AUC of glyburide showed an equality of the two treatments by the analysis of variance. There was an apparent correlation between blood glucose level and the logarithm of plasma glyburide concentration; this relationship appeared to not be altered when glyburide was administered with orlistat. In conclusion, orlistat administered at doses of 80-mg three times daily does not significantly alter the pharmacokinetics and blood glucose-lowering effect of a single 5-mg oral dose of glyburide in healthy volunteers.
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Affiliation(s)
- J Zhi
- Department of Clinical Pharmacokinetics, Hoffmann-La Roche, Inc., Nutley, NJ 07110-1199, USA
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Zhi J, Teller SB, Satoh H, Koss-Twardy SG, Luke DR. Influence of human serum albumin content in formulations on the bioequivalency of interferon alfa-2a given by subcutaneous injection in healthy male volunteers. J Clin Pharmacol 1995; 35:281-4. [PMID: 7608317 DOI: 10.1002/j.1552-4604.1995.tb04059.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To determine the influence of human serum albumin (HSA) content in formulations on the bioequivalency of recombinant interferon alfa-2a, a double-blind, randomized, two-way crossover study was conducted in 24 healthy male volunteers. Subjects received a single subcutaneous injection of 18 million IU of Roferon-A reconstituted with either the diluent containing 10 mg of HSA or the HSA-free diluent; final HSA contents in the 2 formulations were 15 mg and 5 mg, respectively. Administration of the 2 formulations resulted in similar 48-hour Roferon-A serum concentration-time profiles and comparable frequency and intensity of adverse events. The statistical analysis using the two one-sided tests procedure showed that both formulations were bioequivalent for pharmacokinetic parameters such as Cmax, tmax, AUC48, and AUC. We conclude that a threefold change in HSA content in formulations does not alter the bioequivalency of Roferon-A.
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Affiliation(s)
- J Zhi
- Hoffmann-La Roche, Inc., Nutley, NJ 07110-1199, USA
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Zhi J, Massarella JW, Melia AT, Teller SB, Schmitt-Muskus J, Crews T, Oldfield N, Erb RJ, Leese PT, Patel IH. The pharmacokinetic-pharmacodynamic (Digit Symbol Substitution Test) relationship of flumazenil in a midazolam steady-state model in healthy volunteers. Clin Pharmacol Ther 1994; 56:530-6. [PMID: 7955817 DOI: 10.1038/clpt.1994.174] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To characterize the plasma concentration-effect relationship of flumazenil in the presence of a predefined midazolam level, a double-blind, placebo-controlled, randomized two-way crossover study was conducted in nine healthy male subjects. After reaching a criterion level of midazolam-induced depression of the Digit Symbol Substitution Test (DSST), volunteers received a dose of flumazenil (1.0 mg) or placebo over 1 minute, with the infusion of midazolam continued. Blood samples were collected, simultaneously with the DSST assessment, at predetermined intervals and were assayed for flumazenil and/or midazolam plasma concentrations. Pharmacokinetic-pharmacodynamic modeling techniques were used to estimate the equilibration rate constant (keo) between plasma concentration and effect for flumazenil; a sigmoidal maximum-effect model was used to relate the DSST score to the flumazenil plasma concentration. Flumazenil exhibited a rapid onset (the half-life of equilibration between drug concentration in the blood and drug effect was 3.3 minutes) and short duration of action (the flumazenil plasma concentration causing half-maximal effect was 7.4 ng/ml, which was reached about 1 hour after dosing). The results of this study also show the competitive nature of flumazenil as a midazolam antagonist.
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Affiliation(s)
- J Zhi
- Department of Clinical Pharmacokinetics, Hoffman-La Roche, Inc., Nutley, NJ 07110-1199
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Zhi J, Melia AT, Guerciolini R, Chung J, Kinberg J, Hauptman JB, Patel IH. Retrospective population-based analysis of the dose-response (fecal fat excretion) relationship of orlistat in normal and obese volunteers. Clin Pharmacol Ther 1994; 56:82-5. [PMID: 8033498 DOI: 10.1038/clpt.1994.104] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Orlistat, an inhibitor of gastrointestinal lipases, limits the absorption of ingested fat and could become a potential treatment for obesity. This analysis was performed to elucidate the relationship between orlistat dose and intensity of inhibition of dietary fat absorption (assessed by measuring fecal fat excretion). In 11 phase I double-blind, placebo-controlled, parallel-group randomized studies, a total of 171 subjects received oral daily doses that ranged from 30 to 1200 mg orlistat or matching placebo three times a day for 9 to 10 days. The results of the daily mean fecal fat excretion percentage (relative to ingested fat) were correlated to the orlistat daily dose. A simple maximum-effect model that included a basal value was used to fit the dose-response relationship for all evaluable subjects. The mean maximum percentage of ingested fat excreted in the feces was approximately 32% during orlistat administration compared with 5% during placebo administration. The orlistat daily dose that produced 50% of the maximum effect was 98 mg/day. The model-fitting suggests the existence of a steep portion of the dose-response curve up to approximately 400 mg/day, with a subsequent tendency to plateau at higher doses. Such an analysis was instrumental in identifying appropriate doses to be used in therapeutic trials for weight loss in obese patients.
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Affiliation(s)
- J Zhi
- Division of International Clinical Research, Hoffmann-La Roche, Inc., Nutley, NJ 07110-1199
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Zhi J, Nightingale CH. Biphenylacetate, but not theophylline, lethally interacts with ciprofloxacin in mice. Pharmacol Toxicol 1993; 73:285-6. [PMID: 8115312 DOI: 10.1111/j.1600-0773.1993.tb00586.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J Zhi
- Hartford Hospital, CT 06115-0729
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Lubowski TJ, Nightingale C, Sweeney K, Quintiliani R, Zhi J. Penetration of fleroxacin and ciprofloxacin into skin blister fluid: a comparative study. Antimicrob Agents Chemother 1992; 36:651-5. [PMID: 1622179 PMCID: PMC190573 DOI: 10.1128/aac.36.3.651] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The penetration of multiple-dose concentrations of oral fleroxacin (400 mg every 24 h) and ciprofloxacin (500 mg every 12 h) into skin blister fluid in 12 healthy volunteers was determined in a randomized crossover study. Serum, blister fluid, and paper disk samples were analyzed by large-plate microbiologic assay. The mean areas under the concentration-time curve (AUC) for serum were 88.6 and 18.2 micrograms.h/ml/70 kg for fleroxacin and ciprofloxacin, respectively. The mean AUC for blister fluid and paper disks were 71.2 and 15.0 micrograms.h/ml/70 kg and 77.8 and 15.4 micrograms.h/ml/70 kg for fleroxacin and ciprofloxacin, respectively. Calculated penetration into interstitial fluid ranged from 74 to 92% for fleroxacin and 56 to 96% for ciprofloxacin; penetration was calculated by using the ratio of maximum drug concentration or AUC in blister fluid and paper disks to maximum drug concentration or AUC in serum. There was no significant difference between fleroxacin and ciprofloxacin in the percent penetration into skin blister fluid.
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Affiliation(s)
- T J Lubowski
- Division of Infectious Disease/Allergy-Immunology, Hartford Hospital, Connecticut 06115
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Zhi J, Levy G. Optimization of the therapeutic index by adjustment of the rate of drug administration or use of drug combinations: exploratory studies of diuretics. Pharm Res 1990; 7:697-702. [PMID: 2395796 DOI: 10.1023/a:1015855219695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The purpose of this investigation was to explore theoretically certain strategies for optimizing the therapeutic index of drugs and to assess these strategies experimentally with two diuretics. Diuretic agents allow dosing rate flexibilities because the temporal profile of diuretic action can vary considerably as long as the total diuretic effect per day is the same. They can also be used in combination. Experiments were designed to determine if the therapeutic index of furosemide and hydrochlorothiazide can be optimized by administering one or the other at a certain rate or by administering the two drugs together in a certain ratio and at a certain rate. Male Lewis rats received one or the other drug, or combinations of the two, by i.v. infusion at different rates. Several timed urine collections were made under steady-state conditions, with excreted urine replaced volume for volume by i.v. lactated Ringer's solution. The urine flow rates and the urinary excretion rates of the diuretics and of Na+ and K+ were determined. The relationship between the diuretic effect of either of the two drugs given alone and the respective drug excretion rate could be described by the Hill equation. The ratio of urine flow rate to K+ excretion rate exhibited a marked dependence on hydrochlorothiazide excretion rate (highest ratio at high excretion rates), whereas the K+/Na+ excretion rate ratio was constant over a wide range of hydrochlorothiazide excretion rates. There was no significant change of these ratios with changing excretion rate of furosemide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Zhi
- Department of Pharmaceutics, School of Pharmacy, State University of New York, Buffalo, Amherst 14260
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Zhi J, Nightingale CH, Quintiliani R. A pharmacodynamic model for the activity of antibiotics against microorganisms under nonsaturable conditions. J Pharm Sci 1986; 75:1063-7. [PMID: 3102718 DOI: 10.1002/jps.2600751108] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
An exact mathematical solution was derived to a pharmacodynamic model which illustrates bacterial survival in the presence of antibiotics. In this report the survival of Pseudomonas aeruginosa in the medium of an initial concentration of 0.64 mM (320 mg/L) of piperacillin [(2S,5R,6R)-6-[(R)-2-(4-ethyl-2,3-dioxo-1- piperazinecarboxyamido)-2-phenylacetamido]-3,3-dimethyl-7- oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate] was well described by the derived model for up to 24 h. The bacterial killing by the antibiotic and apparent natural growth rate constants were 2955.3 h-1 X mol-1 and 0.5698 h-1, respectively. The functional equation was also fit to the data of ampicillin against Escherichia coli under simulated in vivo conditions. The optimal multiple dosing time and the minimum critical concentration to achieve antimicrobial action can be readily calculated from the developed model. Computer simulations were made to examine the effect on microbial survival of such factors as initial antibiotic concentration (Co), elimination half-life (t1/2), kill rate constant (K) of the antibiotic, and apparent growth rate constant (Kapp) of the test organism.
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