27 results on '"Lau AH"'
Search Results
2. Convenient expressions for computing the exact annual cost of a continuous-review (Q, R) system with backordering
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Lau, AH-L, Lau, H-S, and Robinson, LW
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Inventory control -- Models ,Business ,Business, general - Abstract
For a continuous-review order-quantity reorder point system, the `average on-hand inventory level' (`AOI') is often computed by the approximate Hadley-Whitin expression, while the exact AOI is given by a double integral that appears daunting to both students and practitioners. This paper presents exact AOI expressions that are simple enough to be executed by the most basic business softwares. Numerical examples are provided to illustrate the ease of using these expressions as well as the necessity of using them in situations where the standard Hadley-Whitin approximation becomes too inaccurate. Journal of the Operational Research Society (2002) 53, 655-663. doi: 10.1057/palgrave.jors.2601305 Keywords: inventory; (Q, R) systems
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- 2002
3. Pricing/inventory decisions and profit shares in a non-integrated marketing channel for a single-period product
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Lau, H-S, Lau, AH-L, and Kottas, JF
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Inventory control -- Analysis ,Price control -- Analysis ,Logistics -- Analysis ,Business ,Business, general - Abstract
We consider the situation in which the manufacturer of a single-period product first sets the unit wholesale price and then the retailer responds with an order size. We present mostly analytical results on the effects of the problem's environmental parameters (such as shortage cost and demand uncertainty) on the optimal decisions (ie, the unit wholesale price and retailer's order size) and on the expected profits of the manufacturer and of the retailer. Some of these effects are counter-intuitive and/or contradict related results published recently for similar models. The most important finding is that demand uncertainty is always harmful to the manufacturer but is very often beneficial to the retailer. This means that when the manufacturer can set the wholesale price, the manufacturer should be much more supportive (or even aggressive) than previously advised towards activities such as market surveys and `Quick Response' that reduce the retailer's market uncertainty; in contrast, the retailer need not be as enthusiastic about these activities. Keywords: single period products; inventory; price; supply chain, Please abstract located in the 'Author Abstract' area.
- Published
- 2001
4. Self location of vision guided autonomous mobile robots.
- Author
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Lau, Ah Wai Calvin., Chinese University of Hong Kong Graduate School. Division of Electronic Engineering., Lau, Ah Wai Calvin., and Chinese University of Hong Kong Graduate School. Division of Electronic Engineering.
- Abstract
Lau Ah Wai, Calvin., Thesis (M.Phil.)--Chinese University of Hong Kong, 2000., Includes bibliographical references (leaves 108-111)., s in English and Chinese., Chapter 1 --- Introduction --- p.1, Chapter 1.1 --- An Overview --- p.4, Chapter 1.1.1 --- Robot Self Location --- p.4, Chapter 1.1.2 --- Robot Navigation --- p.10, Chapter 1.2 --- Scope of Thesis --- p.12, Chapter 2 --- Theory --- p.13, Chapter 2.1 --- Coordinate Systems Transformations --- p.13, Chapter 2.2 --- Problem Specification --- p.21, Chapter 2.3 --- The Process of Stereo Vision --- p.22, Chapter 2.3.1 --- Disparity and Depth --- p.22, Chapter 2.3.2 --- Vertical Edge Detection and Extraction --- p.25, Chapter 2.3.3 --- Line Matching Using Dynamic Programming --- p.27, Chapter 3 --- Mobile Robot Self Location --- p.29, Chapter 3.1 --- Physical Points by Stereo Reconstruction --- p.29, Chapter 3.1.1 --- Physical Points Refinement --- p.32, Chapter 3.2 --- Motion Uncertainties Modeling --- p.33, Chapter 3.3 --- Improved Physical Point Estimations by EKF --- p.36, Chapter 3.4 --- Matching Physical Points to Model by Geometric Hashing --- p.40, Chapter 3.4.1 --- Similarity Invariant --- p.44, Chapter 3.5 --- Initial Pose Estimation --- p.47, Chapter 3.5.1 --- Initial Pose Refinement --- p.50, Chapter 3.6 --- Self Location Using Other Camera Combinations --- p.50, Chapter 4 --- Improvements to Self Location Using Bayesian Inference --- p.55, Chapter 4.1 --- Statistical Characteristics of Edges --- p.57, Chapter 4.2 --- Evidence at One Pixel --- p.60, Chapter 4.3 --- Evidence Over All Pixels --- p.62, Chapter 4.4 --- A Simplification Of Geometric Hashing --- p.62, Chapter 4.4.1 --- Simplification of The Similarity Invariant --- p.63, Chapter 4.4.2 --- Translation Invariant --- p.63, Chapter 4.4.3 --- Simplification to The Hashing Table --- p.65, Chapter 5 --- Robot Navigation --- p.67, Chapter 5.1 --- Propagation of Motion Uncertainties to Estimated Pose --- p.68, Chapter 5.2 --- Expectation Map Derived from the CAD Model --- p.70, Chapter 6 --- Experimental Results --- p.74, Chapter 6.1 --- Results Using Simulated Environment --- p.74, Chapter 6.1.1 --- Results and Error Analysis --- p.75, Chapter 6.2 --- Results Using Real Environment --- p.85, Chapter 6.2.1 --- Camera Calibration Using Tsai's Algorithm --- p.85, Chapter 6.2.2 --- Pose Estimation By Geometric Hashing --- p.88, Chapter 6.2.3 --- Pose Estimation by Bayesian Inference and Geometric Hash- ing --- p.90, Chapter 6.2.4 --- Comparison of Self Location Approaches --- p.92, Chapter 6.2.5 --- Motion Tracking --- p.93, Chapter 7 --- Conclusion and Discussion --- p.95, Chapter 7.1 --- Conclusion and Discussion --- p.95, Chapter 7.2 --- Contributions --- p.97, Chapter 7.3 --- Subjects for Future Research --- p.98, Chapter A --- Appendix --- p.100, Chapter A.1 --- Extended Kalman Filter --- p.100, Chapter A.2 --- Visualizing Uncertainty for 2D Points --- p.105, http://library.cuhk.edu.hk/record=b5890320, Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)
- Published
- 2000
5. Pharmacist-led olaparib follow-up service for ambulatory ovarian cancer patients: A prospective study in a tertiary specialized cancer hospital in China.
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Wang Y, Du D, Yang J, Lau AH, Dai Y, Qin W, Li N, and Li G
- Abstract
Purpose: To establish a pharmacist-led olaparib follow-up program for ovarian cancer patients, provide patient education, get information on adverse drug reactions (ADRs), and identify and manage drug-related problems. Methods: Ambulatory adult patients with ovarian cancer receiving olaparib were enrolled. At least one follow-up session was conducted by clinical pharmacists. Pharmacists collected data on the type and grade of ADRs, drug adherence, olaparib dosing, concomitant medications, and pharmacists' suggestions. Results: 83 patients were enrolled with the median age of 58. The average number of the follow-up sessions provided to each patient was 1.31, and the average duration of each follow-up was 17.78 min. The olaparib starting dose for most patients (97.59%) was 600 mg/d. 36.14% of the patients had missed olaparib doses and 27.71% of the patients had dose adjustments due to ADRs. The most common ADRs (incidence≥10%) were: fatigue (40.96%), anemia (36.14%), leukopenia (36.14%), nausea (28.92%), thrombocytopenia (16.87%), anorexia (16.87%), dyspepsia (15.66%). The tolerability profiles were generally similar between patients treated for "first-line maintenance" and those treated for "recurrence maintenance" ( p > .05). There were 42% of the patients who were concomitantly taking medications without exact chemical contents (such as formulated Chinese medicines and Chinese decoctions), and common types of concomitant medications with exact drug names were antihypertensive, anti-hyperglycemic, and anti-hyperlipidemic medications. The pharmacists identified 4 clinically significant drug-drug interactions (DDIs) in two patients. Pharmacists made 196 suggestions mainly related to rational use of the medications and management of ADRs. Conclusion: The study provides the first report about pharmacist-led follow-up service for olaparib. The types of ADRs were similar to those previously observed in clinical trials, and the profiles of ADRs in different types of patients (first-line maintenance vs. recurrence maintenance) were also similar. Pharmacists identified drug-related problems (such as adherence, DDIs and management of ADRs) and offer suggestions for the patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Du, Yang, Lau, Dai, Qin, Li and Li.)
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- 2022
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6. Amauroderma rugosum Extract Suppresses Inflammatory Responses in Tumor Necrosis Factor Alpha/Interferon Gamma-Induced HaCaT Keratinocytes.
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Shiu PH, Li J, Zheng C, Rangsinth P, Li R, Cheung QT, Lau AH, Chan JC, Kwan YW, Cheung TM, and Leung GP
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- Anti-Inflammatory Agents metabolism, Anti-Inflammatory Agents pharmacology, Antioxidants pharmacology, Chemokine CCL2 metabolism, Chemokines metabolism, Cytokines metabolism, Extracellular Signal-Regulated MAP Kinases metabolism, Gallic Acid pharmacology, Guanosine metabolism, Interferon-gamma metabolism, Interferon-gamma pharmacology, Interleukin-1beta metabolism, Interleukin-8 metabolism, Keratinocytes, Mitogen-Activated Protein Kinase Kinases metabolism, NF-kappa B metabolism, Polyporaceae, Proto-Oncogene Proteins c-akt metabolism, Reactive Oxygen Species metabolism, Solvents pharmacology, TOR Serine-Threonine Kinases metabolism, Uridine pharmacology, Triterpenes pharmacology, Tumor Necrosis Factor-alpha metabolism
- Abstract
Keratinocytes form the physical barrier of the skin and play an important role in the inflammatory process. Amauroderma rugosum is an edible mushroom; however, its pharmacological properties have seldom been studied. Although the anti-inflammatory effect of the organic solvent extract of Amauroderma rugosum has been previously reported, it is not known whether the aqueous extract has a similar effect. In addition, the effect of Amauorderma rugosum extract on skin has never been explored. Therefore, the objectives of the present study were to evaluate the anti-inflammatory effects of the aqueous extract of Amauroderma rugosum on HaCaT keratinocytes, to explore its mechanisms of action, and to study the possible active ingredients involved. The results showed that the aqueous extract of Amauroderm rugosum at a concentration of 1.5 mg/mL was non-toxic to HaCaT cells and inhibited the release of cytokine interleukin-1β, and chemokines interleukin-8 and monocyte chemoattractant protein-1 in tumor necrosis factor (TNF)-α- and interferon (IFN)-γ-stimulated HaCaT cells. Amauroderma rugosum extract reduced the intracellular levels of reactive oxygen species. In addition, Amauroderma rugosum extract reduced the total protein expression of nuclear factor-kappa B (NF-κB) and B-cells inhibitor alpha in HaCaT keratinocytes and inhibited the phosphorylation of mitogen-activated protein kinase kinase (MEK) 1/2, extracellular signal-regulated kinase (ERK) 1/2, protein kinase B (Akt), and mammalian target of rapamycin (mTOR) in TNF-α- and INF-γ-stimulated HaCaT keratinocytes. Chemical analysis revealed that the aqueous extract of Amauroderma rugosum contains polysaccharides, triterpenes, and phenolic compounds. Anti-inflammatory compounds, such as gallic acid, guanosine, and uridine, were also present. The anti-inflammatory effect of Amauroderma rugosum could be mimicked by a combination of gallic acid, guanosine, and uridine. In conclusion, our study suggests that the aqueous extract of Amauroderma rugosum exerts anti-inflammatory effects on keratinocytes through its antioxidant and inhibitory effects on MEK/ERK-, Akt/mTOR-, and NF-κB-dependent signaling pathways.
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- 2022
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7. Acupuncture for de Quervain's tenosynovitis: A randomized controlled trial.
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Leung K, Ma OC, Qin Z, Ting H, Lau AH, Lun KK, Chan HY, Wen GY, Ng JT, Chow L, Chu CY, Ho TS, Tsang K, Ng BFL, Fok MWM, Fang CXS, Lao L, and Chen H
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- Humans, Pain etiology, Pain Measurement, Quality of Life, Treatment Outcome, Acupuncture Therapy, Tenosynovitis etiology
- Abstract
Background: Acupuncture has been an alternative approach for de Quervain's tenosynovitis (DQt), but trial evidence is still lacking., Purpose: This study aimed to assess the efficacy of acupuncture in patients with DQt., Study Design: A randomized controlled trial., Methods: A total of 68 subjects with DQt were recruited from outpatients of Department of Orthopaedics and Traumatology, and Chinese medicine clinics, The University of Hong Kong, and were randomized into the acupuncture group (n = 34) and the waitlist group (n = 34). Subjects in the acupuncture group received 5 acupuncture sessions over 2 weeks, followed by a 10-week follow-up. The waitlist control group received assessments only in the first 6 weeks of the waiting period and received the same acupuncture treatment and follow-up as the treatment group in the next 12 weeks. The primary outcome was the general pain intensity using the Visual Analogue Scale (VAS) at the end of treatment (week 2). Secondary outcomes were grip and pinch strengths of affected hands, the quick Disabilities of the Arm, Shoulder and Hand Score (Q-DASH), and the World Health Organization Quality of Life-brief Questionnaire (WHOQOL-BREF) at weeks 2 and 6., Results: From baseline to 2 weeks, the mean VAS score decreased by 19.5 points in the acupuncture group and by 3.4 points in the waitlist group. The difference for acupuncture vs waitlist control was -16.2 points (95% CI, -26.7 to -5.6, p = 0.003). Acupuncture effects sustained for 10 weeks (mean difference compared with baseline, -30.6; 95% CI, -39.6 to -21.7). Secondary outcomes showed that acupuncture reduced pain intensity, improved grip and pinch strength of affected hands, and Q-DASH scores, but not the scores of WHOQOL-BREF in patients. No serious adverse event occurred during the study period., Conclusions: Our findings support that 2-week of acupuncture is safe and effective in the reduction of pain intensity, and improvement of strengths and disabilities of hand in DQt patients. Acupuncture also has long-term effects on DQt., Trial Registration: This study was registered at clinicaltrials.gov (NCT03472443)., (Copyright © 2022 Elsevier GmbH. All rights reserved.)
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- 2022
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8. Student Perspectives on a Collaborative International Doctorate of Pharmacy Program.
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Pham JT, Azzopardi LM, Lau AH, and Jarrett JB
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Objectives: To evaluate the educational experience and teaching methods of the collaborative Doctorate of Pharmacy (PharmD) program between the University of Malta (UM) and the University of Illinois at Chicago (UIC). Methods: A 41-question survey was developed to identify student demographics, satisfaction with the PharmD program and the utility of the current curricular components. Students who enrolled in the program in May 2017 were invited to participate. The survey contained open-ended, 5-point Likert, and multiple-choice type questions. The primary outcomes were the overall satisfaction and student motivations for pursuing the program. Secondary outcomes included the level of difficulty of courses, evaluation of assessment methods, and confidence in an interdisciplinary team. Results: Thirty-six students completed the survey (a response rate of 83.7%). The mean age was 30.1 ± 7.9 years. The majority of the students pursued the PharmD program to improve their knowledge, skills, and opportunity for obtaining a clinical position. The mean overall satisfaction of the program was 3.81 ± 1.1 (5 = very satisfied). Among the core courses, Pharmacotherapeutics had the highest overall satisfaction (4.45 ± 0.91) and level of difficulty (3.84 ± 0.51). Students felt that the tutorials/recitation case discussion sessions were the most effective teaching method (48.4%) and ranked faculties conducting case-based lectures highest for overall performance. Most students felt somewhat confident (54.8%) for participating in a multidisciplinary team. Conclusions: The UM/UIC PharmD Program is a unique program, utilizing a hybrid model of teaching, including distance education, to expose students to a broad and challenging curriculum in clinical pharmacy practice. Students are satisfied with this collaborative, international postgraduate PharmD program.
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- 2019
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9. Combined GS-4774 and Tenofovir Therapy Can Improve HBV-Specific T-Cell Responses in Patients With Chronic Hepatitis.
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Boni C, Janssen HLA, Rossi M, Yoon SK, Vecchi A, Barili V, Yoshida EM, Trinh H, Rodell TC, Laccabue D, Alfieri A, Brillo F, Fisicaro P, Acerbi G, Pedrazzi G, Andreone P, Cursaro C, Margotti M, Santoro R, Piazzolla V, Brunetto MR, Coco B, Cavallone D, Zhao Y, Joshi A, Woo J, Lau AH, Gaggar A, Subramanian GM, Massetto B, Fung S, Ahn SH, Ma X, Mangia A, and Ferrari C
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- Adolescent, Adult, Aged, CD8-Positive T-Lymphocytes immunology, DNA, Viral, Drug Therapy, Combination, Female, Hepatitis B Core Antigens immunology, Hepatitis B Surface Antigens blood, Hepatitis B virus immunology, Hepatitis B, Chronic immunology, Humans, Immune Tolerance immunology, Interferon-gamma immunology, Interleukin-2 immunology, Male, Middle Aged, Trans-Activators immunology, Tumor Necrosis Factor-alpha immunology, Viral Load, Viral Regulatory and Accessory Proteins, Young Adult, Antiviral Agents therapeutic use, Hepatitis B Vaccines therapeutic use, Hepatitis B, Chronic drug therapy, Tenofovir therapeutic use
- Abstract
Background & Aims: One strategy to treat chronic hepatitis B virus (HBV) infection could be to increase the functions of virus-specific T cells. We performed a multicenter phase 2 study to evaluate the safety and efficacy of GS-4774, a yeast-based therapeutic vaccine engineered to express HBV antigens, given with tenofovir disoproxil fumarate (TDF) to untreated patients with chronic HBV infection., Methods: We performed an open-label study at 34 sites in Canada, Italy, New Zealand, Romania, South Korea, and United States from July 2014 to August 2016. Adults who were positive for HB surface antigen (HBsAg) > 6 months and levels of HBV DNA ≥2000 IU/mL who had not received antiviral treatment for HBV within 3 months of screening were randomly assigned (1:2:2:2) to groups given oral TDF 300 mg daily alone (n = 27; controls) or with 2, 10, or 40 yeast units GS-4774 (n = 168), administered subcutaneously every 4 weeks until week 20 for a total of 6 doses. Blood samples were collected and analyzed and patients received regular physical examinations. Efficacy was measured by decrease in HBsAg from baseline to week 24. Specific responses to HBV (production of interferon gamma [IFNG], tumor necrosis factor [TNF], interleukin 2 [IL2], and degranulation) were measured in T cells derived from 12 HBeAg-negative patients with genotype D infections, after overnight or 10 days of stimulation of peripheral blood mononuclear cells with peptides from the entire HBV proteome. T-regulatory cells were analyzed for frequency and phenotype. Data from studies of immune cells were compared with data on reductions in HBsAg, HBV DNA, and alanine aminotransferase in blood samples from patients., Results: GS-4774 was safe and well tolerated but did not produce significant decreases in levels of HBsAg. Production of IFNG, TNF, and IL2 increased significantly at weeks 24 and 48, compared with baseline, in HBV-specific CD8+ T cells from patients given GS-4774 but not from controls. GS-4774 had greater effects on CD8+ than CD4+ T cells, which were not affected at all or very weakly by TDF with or without GS-4774. GS-4774 did not affect responses of T cells to other viruses tested. HBV core peptides induced the greatest production of IFNG by T cells following overnight stimulation, whereas HBV envelope antigens did not induce a response. Following 10 days of stimulation, production of IFNG and TNF increased with time of exposure to GS-4774; the greatest levels of responses were to HBV envelope antigens followed by core and polymerase peptides. We observed a correlation in patients given GS-4774 between increased T-cell functions and reductions in numbers of T-regulatory cells., Conclusions: In a phase 2 study of patients with chronic HBV infection given TDF with or without GS-4774, we found that vaccination can increase production of IFNG, TNF, and IL2 by CD8+ T cells exposed to antigenic peptides, with little effect on CD4+ T cells. Although GS-4774 did not reduce levels of HBsAg in patients, its strong immune stimulatory effect on CD8+ T cells might be used in combination with other antiviral agents to boost the antivirus immune response. Clinicaltrials.gov no: NCT02174276., (Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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10. Improved Bone Safety of Tenofovir Alafenamide Compared to Tenofovir Disoproxil Fumarate Over 2 Years in Patients With Chronic HBV Infection.
- Author
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Seto WK, Asahina Y, Brown TT, Peng CY, Stanciu C, Abdurakhmanov D, Tabak F, Nguyen TT, Chuang WL, Inokuma T, Ikeda F, Santantonio TA, Habersetzer F, Ramji A, Lau AH, Suri V, Flaherty JF, Wang H, Gaggar A, Subramanian GM, Mukewar S, Brunetto MR, Fung S, and Chan HL
- Abstract
Background & Aims: Long-term use of tenofovir disoproxil fumarate (TDF) reduces bone mineral density (BMD). Tenofovir alafenamide (TAF), a new prodrug of tenofovir, has shown non-inferior efficacy to TDF in patients with chronic hepatitis B virus (HBV) infection, with improved bone effects at 48 weeks. We performed a randomized trial to evaluate the bone safety of TAF compared with TDF over 2 years, assessing baseline risk factors for bone loss, were evaluated after 2 years of treatment., Methods: In a double-blind study, hepatitis B e antigen (HBeAg)-positive patients (n = 873) and HBeAg-negative patients (n = 425) were randomly assigned (2:1) to groups given TAF (25 mg; n = 866) or TDF (300 mg; n = 432) once daily. We assessed bone safety, including hip and spine BMD, using dual-energy X-ray absorptiometry and measured changes in serum markers of bone turnover over 96 weeks., Results: At baseline, treatment groups were well matched. At week 96, patients receiving TAF had significantly smaller decreases in hip BMD (mean reduction of 0.33%) than patients receiving TDF (mean reduction of 2.51%) (P < .001) and spine BMD (reduction of 0.75% in patients receiving patients receiving TAF vs reduction of 2.57% in patients receiving TDF) (P < .001). For hip BMD, the magnitude of difference in bone loss between the TAF and TDF groups increased at week 96 compared to week 48 (P < .001). The TAF group had minimal changes in markers of bone turnover by 12 weeks of treatment, but the TDF group had significant changes, compared to baseline. Risk factors for bone loss had fewer effects in patients receiving TAF than TDF at week 96., Conclusions: In double-blind randomized trials, we found that after 2 years of treatment, patients receiving TAF had continued improvements in bone safety compared with patients receiving TDF. Clinicaltrial.gov ID NCT01940471 and NCT01940341., (Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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11. Applying Mass Cytometry to the Analysis of Lymphoid Populations in Transplantation.
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Krams SM, Schaffert S, Lau AH, and Martinez OM
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- Animals, Humans, Flow Cytometry instrumentation, Image Processing, Computer-Assisted methods, Lymphoid Tissue diagnostic imaging, Lymphoid Tissue immunology, Organ Transplantation
- Abstract
Single-cell flow cytometric techniques have been indispensable to improving our understanding of the phenotype and function of immune cell subsets that are important in both rejection and tolerance after transplant. Mass cytometry, or cytometry by time of flight, is a single-cell-based platform that utilizes antibodies conjugated to rare heavy metal ions for analysis of cellular proteins by a time-of-flight mass spectrometer. This new technology allows for the evaluation of >40 simultaneous cellular parameters in a single sample because the limitation of spectral overlap, seen in conventional flow cytometry, is eliminated. In this review, we discuss the current state of mass cytometry, describe the advantages and disadvantages compared with multiparameter flow cytometry, introduce novel methods of high-dimensional data analysis and visualization, and review some recent studies using mass cytometry to profile the immune systems of healthy people and transplant recipients., (© 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.)
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- 2017
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12. A prospective randomized controlled study on the treatment outcome of SpineCor brace versus rigid brace for adolescent idiopathic scoliosis with follow-up according to the SRS standardized criteria.
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Guo J, Lam TP, Wong MS, Ng BK, Lee KM, Liu KL, Hung LH, Lau AH, Sin SW, Kwok WK, Yu FW, Qiu Y, and Cheng JC
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- Adolescent, Child, Disease Progression, Equipment Design, Female, Follow-Up Studies, Humans, Patient Outcome Assessment, Prospective Studies, Risk Factors, Braces, Scoliosis therapy
- Abstract
Purpose: SpineCor is a relatively innovative brace for non-operative treatment of adolescent idiopathic scoliosis (AIS). However, the effectiveness of SpineCor still remains controversial. The objective of the current study was to compare the treatment outcomes of SpineCor brace with that of rigid brace following the standardized Scoliosis Research Society (SRS) criteria on AIS brace study., Methods: Females subjects with AIS and aged 10-14 were randomly allocated into two groups undergoing treatment of SpineCor (S Group, n = 20) or rigid brace (R Group, n = 18). During SpineCor treatment, patients who had curve progression of >5° would be required to switch to rigid brace treatment. The effectiveness of the two brace treatments was assessed using the SRS standardized criteria., Results: Before skeletal maturity, 7 (35.0%) patients in the S Group and 1 (5.6%) patient in the R Group had curve progression >5° (P = 0.026). At skeletal maturity, 5 of the 7 (71.4%) patients who failed with SpineCor bracing showed control from further progression by changing to rigid bracing. At the latest follow-up with a mean duration of 45.1 months after skeletally maturity, 29.4% of patients who were successfully treated by rigid brace showed further curve progression beyond skeletal maturity, versus 38.5% of patients in the SpineCor group (P > 0.05). For both groups, the primary curves were slightly improved at the time of brace weaning, but additionally increased at the latest follow-up, with a rate of 1.5° per year for post-maturity progression., Conclusions: Curve progression rate was found to be significantly higher in the SpineCor group when compared with the rigid brace group. Changing to rigid bracing could control further curve progression for majority of patients who previously failed with SpineCor bracing. For both SpineCor and rigid brace treatments, 30-40% of patients who were originally successfully treated by bracing would exhibit further curve progression beyond skeletal maturity. The post-maturity progression rate was found to be 1.5° per year in the current study, which was relatively greater than those reported before.
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- 2014
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13. In situ phylogenetic structure and diversity of wild Bradyrhizobium communities.
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Sachs JL, Kembel SW, Lau AH, and Simms EL
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- Bradyrhizobium genetics, Cluster Analysis, DNA, Bacterial chemistry, DNA, Bacterial genetics, DNA, Ribosomal Spacer chemistry, DNA, Ribosomal Spacer genetics, Molecular Sequence Data, Phylogeny, Sequence Analysis, DNA, Biodiversity, Bradyrhizobium classification, Bradyrhizobium isolation & purification, Lotus microbiology, Plant Roots microbiology
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Bacteria often infect their hosts from environmental sources, but little is known about how environmental and host-infecting populations are related. Here, phylogenetic clustering and diversity were investigated in a natural community of rhizobial bacteria from the genus Bradyrhizobium. These bacteria live in the soil and also form beneficial root nodule symbioses with legumes, including those in the genus Lotus. Two hundred eighty pure cultures of Bradyrhizobium bacteria were isolated and genotyped from wild hosts, including Lotus angustissimus, Lotus heermannii, Lotus micranthus, and Lotus strigosus. Bacteria were cultured directly from symbiotic nodules and from two microenvironments on the soil-root interface: root tips and mature (old) root surfaces. Bayesian phylogenies of Bradyrhizobium isolates were reconstructed using the internal transcribed spacer (ITS), and the structure of phylogenetic relatedness among bacteria was examined by host species and microenvironment. Inoculation assays were performed to confirm the nodulation status of a subset of isolates. Most recovered rhizobial genotypes were unique and found only in root surface communities, where little bacterial population genetic structure was detected among hosts. Conversely, most nodule isolates could be classified into several related, hyper-abundant genotypes that were phylogenetically clustered within host species. This pattern suggests that host infection provides ample rewards to symbiotic bacteria but that host specificity can strongly structure only a small subset of the rhizobial community.
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- 2009
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14. Effects of lanthanum carbonate on the absorption and oral bioavailability of ciprofloxacin.
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How PP, Fischer JH, Arruda JA, and Lau AH
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- Administration, Oral, Adult, Area Under Curve, Biological Availability, Cross-Over Studies, Drug Interactions, Female, Humans, Male, Middle Aged, Time Factors, Anti-Infective Agents pharmacokinetics, Ciprofloxacin pharmacokinetics, Intestinal Absorption drug effects, Lanthanum pharmacology
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Background and Objectives: Phosphate binders such as calcium salts or sevelamer, a cationic polymer, can markedly reduce absorption of oral ciprofloxacin. This randomized, open-label, two-way, crossover study examined the influence of the cation lanthanum on systemic ciprofloxacin exposure after oral administration., Design, Setting, Participants, & Measurements: Twelve patients randomly received in a crossover manner a single oral dose of ciprofloxacin 750 mg alone and plus lanthanum carbonate 1 g three times daily with meals for six doses, with a washout interval of 7 to 14 d. Serial blood and urine samples were collected for 24 h after ciprofloxacin administration, and ciprofloxacin concentrations were determined using reverse-phase HPLC. Pharmacokinetic parameters of ciprofloxacin were calculated by noncompartmental methods, and the effect of lanthanum on ciprofloxacin pharmacokinetic parameters was assessed using ANOVA., Results: Lanthanum decreased (P < 0.001) the mean ciprofloxacin area under the plasma concentration-time curve by 54% and the maximum plasma concentration by 56%. The 24-h urinary recovery of ciprofloxacin was reduced by 52% by lanthanum (P < 0.001). No statistically significant differences in ciprofloxacin time to maximum plasma concentration, elimination half-life, and renal clearance occurred between the two arms., Conclusions: Lanthanum carbonate significantly reduces the systemic exposure to orally administered ciprofloxacin. Concomitant administration of both drugs should be avoided to prevent possible suboptimal response to ciprofloxacin.
- Published
- 2007
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15. Ethanol affects the generation, cosignaling molecule expression, and function of plasmacytoid and myeloid dendritic cell subsets in vitro and in vivo.
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Lau AH, Abe M, and Thomson AW
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- Alcohol-Induced Disorders physiopathology, Animals, Antigens, Surface drug effects, Antigens, Surface immunology, Bone Marrow Cells drug effects, Bone Marrow Cells immunology, Cell Differentiation immunology, Cell Proliferation drug effects, Central Nervous System Depressants toxicity, Cytokines drug effects, Cytokines immunology, Dendritic Cells immunology, Disease Models, Animal, Immune Tolerance immunology, Immunity, Cellular immunology, Liver cytology, Liver drug effects, Liver immunology, Mice, Mice, Inbred BALB C, Mice, Inbred C3H, Mice, Inbred C57BL, Plasma Cells drug effects, Plasma Cells immunology, Signal Transduction drug effects, Signal Transduction immunology, Spleen cytology, Spleen drug effects, Spleen immunology, Stem Cells drug effects, Stem Cells immunology, T-Lymphocytes drug effects, T-Lymphocytes immunology, Alcohol-Induced Disorders immunology, Cell Differentiation drug effects, Dendritic Cells drug effects, Ethanol toxicity, Immune Tolerance drug effects, Immunity, Cellular drug effects
- Abstract
The influence of ethanol (EtOH) on multiple dendritic cell (DC) subsets, in the steady state or following their mobilization in vivo, has not been characterized. Herein, generation of mouse bone marrow-derived DC (BMDC) in response to fms-like tyrosine kinase 3 ligand was inhibited by physiologically relevant concentrations of EtOH with selective suppression of plasmacytoid (p)DC. EtOH reduced surface expression of costimulatory molecules (CD40, CD80, CD86) but not that of coinhibitory CD274 (B7-H1) on resting or CpG-stimulated DC subsets. Interleukin (IL)-12p70 production by activated DC was impaired. Consistent with these findings, EtOH-exposed BMDC exhibited a reduced capacity to induce naïve, allogeneic T cell proliferation and impaired ability to prime T cells in vivo. DC subsets freshly isolated from EtOH-fed mice were also examined. Liver DC, inherently immature and resistant to maturation, exhibited little change in their low surface cosignaling molecule expression, whereas splenic DC showed reduced expression of surface costimulatory molecules in response to CpG stimulation in vivo. These splenic DC elicited reduced naïve, allogeneic T cell proliferation in vitro, and the stimulatory capacity of resting but not CpG-activated liver DC was reduced by chronic EtOH administration. T cells from animals primed with EtOH-exposed DC produced elevated levels of IL-10 following ex vivo challenge with donor alloantigen. Thus, EtOH impairs cytokine-driven differentiation and function of myeloid DC and pDC in vitro. Hepatic DC from chronic EtOH-fed mice are less affected than splenic DC, which exhibit impaired functional maturation following CpG stimulation. These results indicate a potential mechanism by which alcohol consumption is associated with immunosuppression.
- Published
- 2006
- Full Text
- View/download PDF
16. Disparate ability of murine CD8alpha- and CD8alpha+ dendritic cell subsets to traverse endothelium is not determined by differential CD11b expression.
- Author
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Colvin BL, Lau AH, Schell AM, and Thomson AW
- Subjects
- Animals, Cell Adhesion Molecules immunology, Cell Differentiation immunology, Chemokine CCL19, Chemokine CCL21, Chemokines, CC immunology, Endothelium, Vascular immunology, Immunophenotyping, Intercellular Adhesion Molecule-1 immunology, Male, Mice, CD11b Antigen metabolism, CD8 Antigens analysis, Chemotaxis immunology, Dendritic Cells immunology, Endothelial Cells immunology
- Abstract
Upon Ag uptake and response to maturation stimuli, dendritic cells (DC) are directed through lymphatic or blood vessel endothelium to T cell areas of secondary lymphoid tissues by the constitutively expressed CC chemokines CCL19 and CCL21. We have shown that mature (m) murine CD8alpha+ DC exhibit poorer migratory ability to these chemokines than classic CD8alpha- DC by quantifying their in vitro chemotaxis through unmodified Transwell filters. We hypothesized that lower surface expression (compared to CD8alpha- mDC) of the adhesion molecule CD11b on CD8alpha+ DC might limit their ability to adhere to filter pores in vitro and/or endothelium in vitro/in vivo. To test the role of this and/or other adhesion molecules (CD11a, CD31, CD54 and CD62L) in regulating murine DC subset migration, we used specific mAbs to block their function and quantified their migration through resting or tumour necrosis factor (TNF)-alpha-activated endothelial cell (EC) layered-Transwell filters. Both CD8alpha+ and CD8alpha- subsets migrated through resting EC (albeit less than in the absence of EC) in response to CCL19 and CCL21, and migration through TNF-alpha-activated EC was enhanced. In contrast to reports concerning human DC, transendothelial migration of the murine DC subsets was not dependent on CD11b, CD31, or CD62L expression by these cells. CD54 and CD11a, however, were at least partly involved in DC/EC interactions. This is the first report to examine adhesion molecules involved in transendothelial migration of murine DC subsets.
- Published
- 2004
- Full Text
- View/download PDF
17. Comparative evaluation of CC chemokine-induced migration of murine CD8alpha+ and CD8alpha- dendritic cells and their in vivo trafficking.
- Author
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Colvin BL, Morelli AE, Logar AJ, Lau AH, and Thomson AW
- Subjects
- Animals, Chemokines, CC analysis, Dendritic Cells immunology, Dendritic Cells transplantation, Lymph Nodes cytology, Lymphocyte Culture Test, Mixed, Mice, Mice, Inbred Strains, RNA, Messenger analysis, Receptors, Chemokine analysis, Receptors, Chemokine genetics, Spleen cytology, T-Lymphocytes immunology, Transplantation, Homologous, CD8 Antigens, Chemokines, CC physiology, Chemotaxis, Dendritic Cells cytology
- Abstract
Murine CD11c(+)CD8alpha(-) and CD11c(+)CD8alpha(+) dendritic cells (DCs) differentially regulate T cell responses. Although specific chemokines that recruit immature (i) or mature (m) CD8alpha(-) DCs have been identified, little is known about the influence of chemokines on CD8alpha(+) DCs. iDCs and mDCs isolated from spleens of fms-like tyrosine kinase 3 ligand-treated B10 mice were compared directly for migratory responses to a panel of CC chemokines or following local or systemic administration. In vitro assays were performed using Transwell(R) chambers. iDCs did not respond to any CC chemokines tested. Both subsets of mDCs migrated to CCL19 and CCL21, with consistently lower percentages of CD8alpha(+) DCs migrating. Chemokine receptor mRNA and protein expression were analyzed, but no correlation between expression and function was demonstrated. In vivo trafficking of fluorochrome-labeled DCs (B10; H2(b)) was assessed by immunohistochemistry and by rare-event flow cytometric analysis of allogeneic recipient (BALB/c; H2(d)) draining lymph node (DLN) and spleen cells. Twenty-four hours after intravenous injection, chloromethylfluorescein diacetate-positive CD8alpha(+) and CD8alpha(-) mDCs were detected by immunohistochemistry in spleens in similar numbers (that decreased over time). Following subcutaneous injection, both DC subsets were detected in DLN at 24 h, but only CD8alpha(-) DCs were evident by flow analysis at 48 h. Although CD8alpha(+) DCs migrate from peripheral tissues to T cell areas of (allogeneic) secondary lymphoid organs, they appear to mobilize as mDCs and less efficiently than CD8alpha(-) mDCs.
- Published
- 2004
- Full Text
- View/download PDF
18. Dendritic cells and immune regulation in the liver.
- Author
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Lau AH and Thomson AW
- Subjects
- Antigens, CD immunology, Carcinoma, Hepatocellular immunology, Cell Count, Chemotaxis immunology, Hepatitis, Viral, Human immunology, Humans, Immune Tolerance immunology, Immunity, Cellular immunology, Leukocytes immunology, Liver pathology, Liver Diseases pathology, Liver Neoplasms immunology, Liver Transplantation immunology, Lymph cytology, Lymph immunology, Lymphoid Tissue immunology, Phagocytosis immunology, Phenotype, Stem Cells immunology, T-Lymphocytes immunology, Transforming Growth Factor beta immunology, Dendritic Cells immunology, Liver immunology, Liver Diseases immunology
- Abstract
Hepatic dendritic cells (DC) unquestionably play important roles in the induction and regulation of immune responses. Due to their paucity, functional characterisation of these important antigen presenting cells has been slow but use of DC growth factors (in particular GM-CSF and Flt3L) that markedly enhance their numbers has proved helpful in furnishing adequate study material. While there is growing evidence that DC function is affected in the pathogenesis of liver disease, most work to date has been performed on non-hepatic DC. Increasing knowledge of hepatic DC biology is likely to improve our understanding of disease pathogenesis and resistance to and therapy of liver disease.
- Published
- 2003
- Full Text
- View/download PDF
19. Apoptosis induced by cisplatin nephrotoxic injury.
- Author
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Lau AH
- Subjects
- Animals, Caspase 1 metabolism, Caspase 3, Caspases metabolism, Cell Survival drug effects, Kidney drug effects, Kidney enzymology, LLC-PK1 Cells cytology, LLC-PK1 Cells drug effects, LLC-PK1 Cells enzymology, Swine, Antineoplastic Agents toxicity, Apoptosis drug effects, Cisplatin toxicity, Kidney cytology
- Abstract
An agent often used in cancer treatment, cisplatin may cause acute renal failure after even a single dose. Recent laboratory studies confirmed the induction of renal cell apoptosis by cisplatin. Reduction in cell viability as well as increase in the number of cells with fragmented nuclei correlated with cisplatin exposure in a dose-dependent manner. Gel electrophoresis revealed the presence of a characteristic laddering pattern which was preceded by an increase in caspase-3 activity. As the cisplatin concentration increased beyond 50 microM, the elevation of caspase-3 activity declined, which suggests that necrosis, instead of apoptosis, is more likely to be responsible for cell death secondary to higher cisplatin concentrations. Elucidation of the molecular mechanisms of cisplatin nephrotoxicity may lead to the development of a novel therapeutic strategy that targets cancer cell death while simultaneously minimizing renal injury.
- Published
- 1999
- Full Text
- View/download PDF
20. Using activity-based costing to track resource use in group practices.
- Author
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Zeller TL, Siegel G, Kaciuba G, and Lau AH
- Subjects
- Benchmarking, Cost Control methods, Health Resources economics, Humans, United States, Accounting methods, Cost Allocation methods, Group Practice economics, Health Resources statistics & numerical data, Orthopedics economics, Practice Management, Medical economics, Process Assessment, Health Care economics
- Abstract
Research shows that understanding how resources are consumed can help group practices control costs. An American Academy of Orthopaedic Surgeons study used an activity-based costing (ABC) system to measure how resources are consumed in providing medical services. Teams of accounting professors observed 18 diverse orthopedic surgery practices. The researchers identified 17 resource-consuming business processes performed by nonphysician office staff. They measured resource consumption by assigning costs to each process according to how much time is spent on related work activities. When group practices understand how their resources are being consumed, they can reduce costs and optimize revenues by making adjustments in how administrative and clinical staff work.
- Published
- 1999
21. PROBES: a framework for probability elicitation from experts.
- Author
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Lau AH and Leong TY
- Subjects
- Colorectal Neoplasms diagnosis, Evaluation Studies as Topic, Humans, Recurrence, Software, Colorectal Neoplasms therapy, Decision Support Techniques, Probability
- Abstract
A decision analytic model represents uncertainties as probability distributions. These distributions are hard to assess especially for large and dynamic models. We propose an integrated framework that facilitates elicitation of the relevant probability distributions for dynamic decision models from the domain experts. The experts usually use some judgmental heuristics to aid probability assessments; the resulting distributions may be proned to cognitive biases. Our framework aims to minimize the effects of these biases and to improve the quality of decisions made. We have implemented a prototype system of the framework and evaluated its effectiveness via a case study in the follow-up management of colorectal cancer patients after curative surgery. Preliminary results demonstrate the practical promise of the framework.
- Published
- 1999
22. Pharmacokinetics and safety of tiagabine in subjects with various degrees of hepatic function.
- Author
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Lau AH, Gustavson LE, Sperelakis R, Lam NP, El-Shourbagy T, Qian JX, and Layden T
- Subjects
- Administration, Oral, Adult, Aged, Anticonvulsants blood, Chromatography, High Pressure Liquid, Circadian Rhythm, Creatinine blood, Dose-Response Relationship, Drug, Female, Half-Life, Humans, Incidence, Liver Diseases blood, Liver Diseases diagnosis, Male, Middle Aged, Nervous System Diseases blood, Nervous System Diseases chemically induced, Nervous System Diseases epidemiology, Neurologic Examination, Nipecotic Acids blood, Serum Albumin analysis, Severity of Illness Index, Tiagabine, Ultrafiltration, Anticonvulsants adverse effects, Anticonvulsants pharmacokinetics, Liver Diseases metabolism, Nipecotic Acids adverse effects, Nipecotic Acids pharmacokinetics
- Abstract
Purpose: To evaluate the pharmacokinetics and safety of multiple oral doses of tiagabine HCl in subjects with different degrees of hepatic impairment., Methods: Four subjects with mild hepatic impairment, three subjects with moderate hepatic impairment, and six matched normal subjects received twice daily oral tiagabine HCl for 5.5 days. Serial blood specimens were obtained for 48 h after the final dose. Total and unbound tiagabine plasma concentrations were determined by high-performance liquid chromatography (HPLC) and ultrafiltration, respectively. Pharmacokinetic parameters were compared between the groups by analysis of covariance., Results: For total tiagabine concentrations in normal subjects and subjects with mild and moderate hepatic impairment, C(max) values (mean +/- SD) were 117 +/- 54, 172 +/- 40, and 172 +/- 28 ng/ml; C(min) values were 13 +/- 4, 27 +/- 4, and 28 +/- 6 ng/ml; areas under the plasma concentration-time curve were 396 +/- 59, 633 +/- 16, and 675 +/- 32 ng x h/ml, and elimination half-lives (harmonic means) were 7, 12, and 16 h, respectively. Unbound tiagabine concentrations, area under the unbound plasma concentration-time curve, and the free fractions were increased in the hepatically impaired subjects. Reduced serum albumin and alpha1-acid glycoprotein concentrations may have contributed to increases in the unbound fraction. Adverse events observed included dizziness, tremor, nausea, somnolence, incoordination, and unsteady gait. The frequency of these events was increased in the subjects with liver impairment., Conclusions: Because of the decreased drug elimination caused by liver function impairment, reduced doses or increased dosing interval or both may be needed to attain therapeutic plasma drug concentrations. Time to reach steady state also may be prolonged. The patients should be monitored closely for potential neurologic adverse events.
- Published
- 1997
- Full Text
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23. Estimating equilibrated Kt/V from an intradialytic sample: effects of access and cardiopulmonary recirculations.
- Author
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Pflederer BR, Torrey C, Priester-Coary A, Lau AH, and Daugirdas JT
- Subjects
- Female, Humans, Male, Coronary Circulation, Pulmonary Circulation, Renal Dialysis, Urea pharmacokinetics
- Abstract
The Smye method has been proposed to estimate the equilibrated post-dialysis BUN based on an additional intradialytic sample obtained approximately one hour into dialysis. However, the effects of access recirculation (AR) and cardiopulmonary recirculation (CPR) on the Smye computation and the corresponding details of how blood is sampled have not been studied. We examined the accuracy of two variations of the Smye technique. In one method, the intradialytic and postdialysis blood samples were obtained at full blood flow. In the other, the samples were obtained after two minutes of slow flow, to obviate the effects of both AR and CPR. Seventeen patients undergoing high efficiency dialysis and three- to four-hour treatment times were studied, in whom substantial AR was excluded based on two-minute slow flow urea rebound measurements during and just after dialysis. In this group equilibrated Kt/V (eKt/V) values computed using the Smye-derived equilibrated postBUN estimates (full flow samples, 1.22 +/- 0.058 SEM, slow flow samples, 1.23 +/- 0.064) were similar to eKt/V calculated from the 30-minute postdialysis BUN specimen (1.23 +/- 0.049, P = NS). In eight other patients with severe AR (mean 35% +/- 4.5), the accuracy of the full flow Smye estimates was poor when the degree of AR was not constant throughout the dialysis session. Accuracy of the slow flow Smye estimates of eKt/V was unaffected by the presence of severe AR. One advantage of using the full flow Smye method, however, was that a large delta Kt/V value ( < -0.40) was highly suggestive of severe AR.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1995
- Full Text
- View/download PDF
24. Chloramphenicol pharmacokinetics in hospitalized patients.
- Author
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Koup JR, Lau AH, Brodsky B, and Slaughter RL
- Subjects
- Adolescent, Aged, Chloramphenicol administration & dosage, Chloramphenicol blood, Female, Humans, Infant, Kinetics, Male, Protein Binding, Time Factors, Chloramphenicol metabolism
- Abstract
The apparent body clearance of chloramphenicol was investigated in 21 hospitalized adult patients on 27 occasions. Apparent body clearance was found to be significantly lower (1.99 +/- 1.49 ml/min per kg) in patients with total serum bilirubin concentrations of >1.5 mg/100 ml than in patients with serum bilirubin concentrations of =1.5 mg/100 ml (3.57 +/- 1.72 ml/min per kg; P < 0.001). Serum protein binding of chloramphenicol was lower in cirrhotic patients (42.2 +/- 6.8% bound) than in normal adults (53.1 +/- 5.2% bound; P < 0.001). Low binding of chloramphenicol was also found in the serum of premature neonates (32.4 +/- 8.2% bound; P < 0.001). Reduced binding in neonates implies the need for a lower therapeutic range of total chloramphenicol concentration (3.5 to 13.9 mug/ml) compared with the usual adult range (5 to 20 mug/ml). Finally, three case reports are presented which demonstrate marked abnormalities and intrasubject variation in chloramphenicol clearance.
- Published
- 1979
- Full Text
- View/download PDF
25. Pharmacokinetics of metronidazole in patients with alcoholic liver disease.
- Author
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Lau AH, Evans R, Chang CW, and Seligsohn R
- Subjects
- Adult, Female, Half-Life, Humans, Male, Middle Aged, Liver Diseases, Alcoholic metabolism, Metronidazole pharmacokinetics
- Abstract
The pharmacokinetics of metronidazole was evaluated in eight patients with alcoholic liver disease. Metronidazole (7.5 mg/kg) was administered to each patient intravenously. Serial blood samples were obtained after the dose. Serum metronidazole concentrations were determined by high-performance liquid chromatography. The following pharmacokinetic parameters (mean +/- standard deviations) were obtained: half-life, 18.31 +/- 6.06 h; elimination rate constant, 0.042 +/- 0.013 h-1; volume of distribution, 0.77 +/- 0.16 liters/kg; and total body clearance, 0.51 +/- 0.11 ml/min per kg. Compared with subjects with normal liver function, patients with liver disease showed a reduction in drug elimination rate and total body clearance. The half-life of metronizadole in serum and volume of distribution were increased. Large variations of these parameters were also observed among the patients. On the basis of these observations, a reduced dose of metronidazole should be given to patients with alcoholic liver disease to avoid accumulation of metronidazole and its metabolites. Monitoring of drug concentration in serum may also be necessary to optimize therapy.
- Published
- 1987
- Full Text
- View/download PDF
26. Relationship between serum and saliva chloramphenicol concentrations.
- Author
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Koup JR, Lau AH, Brodsky B, and Slaughter RL
- Subjects
- Adult, Chloramphenicol blood, Humans, Protein Binding, Chloramphenicol metabolism, Saliva metabolism
- Abstract
The relationship between serum and saliva chloramphenicol (CAP) concentrations was evaluated in 27 paired specimens collected from 20 hospitalized patients during therapy with the drug. A significant (R = 0.80, P < 0.001) but variable relationship was found to exist. Serum protein binding of CAP was also evaluated (43.7 +/- 5.7% bound; N = 24). Differences in CAP binding did not apparently account for a significant portion of the variability in the observed saliva/serum CAP concentration ratios. The degree of variation observed indicated that saliva CAP concentrations could not be relied upon for the prediction of serum CAP concentrations.
- Published
- 1979
- Full Text
- View/download PDF
27. Hemodialysis clearance of metronidazole and its metabolites.
- Author
-
Lau AH, Chang CW, and Sabatini S
- Subjects
- Acute Kidney Injury complications, Adult, Cellulose analogs & derivatives, Female, Humans, Kidney Failure, Chronic complications, Kinetics, Male, Membranes, Artificial, Middle Aged, Metronidazole metabolism, Renal Dialysis
- Abstract
Metronidazole is now being used with increasing frequency for various infectious conditions in patients with renal failure. It is commonly administered to septic patients who have developed acute renal failure requiring hemodialysis. The hemodialysis clearances of metronidazole and its metabolites were evaluated in nine renal failure patients on maintenance hemodialysis. The mean +/- standard deviation clearance and the extraction ratio were 106.9 +/- 16.3 ml/min and 0.65 +/- 0.08, respectively, when regenerated cellulose dialysis membrane was used. The clearance and the extraction ratio with the use of cuprophan membrane were 72.1 +/- 17.3 ml/min and 0.44 +/- 0.12, respectively. The clearances and extraction ratios for the metabolites were similar to those of the parent drug. For both metronidazole and the hydroxy metabolite, the clearance and the extraction ratio demonstrated a statistically significant difference between the regenerated cellulose membrane and the cuprophan membrane. In summary, metronidazole and its metabolites were found to be highly dialyzable with different clearances depending on the specific type of membrane used. However, owing to the relatively wide therapeutic index of the drug, dosage supplementation may be necessary only in seriously ill patients to ensure therapeutic effect.
- Published
- 1986
- Full Text
- View/download PDF
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