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Wong SYS, Tang WK, Mak WWS, Cheung FMC, Mercer S, Griffiths SM, Woo J, Lee DTF, Kung K, Lam AT. Stepped care programme in primary care to prevent anxiety and depression: a randomised clinical trial. Hong Kong Med J 2019; 25 Suppl 3:9-10. [PMID: 30792364] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023] Open
Affiliation(s)
- S Y S Wong
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong
| | - W K Tang
- Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong
| | - W W S Mak
- Department of Psychology, The Chinese University of Hong Kong
| | - F M C Cheung
- Department of Psychology, The Chinese University of Hong Kong
| | - S Mercer
- General Practice and Primary Care, University of Glasgow, Glasgow, United Kingdom
| | - S M Griffiths
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong
| | - J Woo
- Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong
| | - D T F Lee
- The Nethersole School of Nursing, The Chinese University of Hong Kong
| | - K Kung
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong
| | - A T Lam
- New Territories East Cluster, Hospital Authority, Hong Kong
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Lam AT, VanDelinder V, Kabir AMR, Hess H, Bachand GD, Kakugo A. Cytoskeletal motor-driven active self-assembly in in vitro systems. Soft Matter 2016; 12:988-997. [PMID: 26576824 DOI: 10.1039/c5sm02042e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecular motor-driven self-assembly has been an active area of soft matter research for the past decade. Because molecular motors transform chemical energy into mechanical work, systems which employ molecular motors to drive self-assembly processes are able to overcome kinetic and thermodynamic limits on assembly time, size, complexity, and structure. Here, we review the progress in elucidating and demonstrating the rules and capabilities of motor-driven active self-assembly. We focus on the types of structures created and the degree of control realized over these structures, and discuss the next steps necessary to achieve the full potential of this assembly mode which complements robotic manipulation and passive self-assembly.
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Affiliation(s)
- A T Lam
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, MC 8904, New York, NY 10027, USA.
| | - V VanDelinder
- Sandia National Laboratories, Nanosystems Synthesis/Analysis Dept., Albuquerque, NM, USA.
| | - A M R Kabir
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - H Hess
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, MC 8904, New York, NY 10027, USA.
| | - G D Bachand
- Sandia National Laboratories, Nanosystems Synthesis/Analysis Dept., Albuquerque, NM, USA.
| | - A Kakugo
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan and Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan.
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Lam AT, Faragó EP, Owen MC, Fiser B, Jójárt B, Jensen SJK, Csizmadia IG, Viskolcz B. The effect of oxidative stress on the bursopentin peptide structure: a theoretical study. Phys Chem Chem Phys 2015; 16:9602-9. [PMID: 24730022 DOI: 10.1039/c3cp54799j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bursopentin (BP(5), H-Cys(1)-Lys(2)-Arg(3)-Val(4)-Tyr(5)-OH), found in the bursa Fabricius of the chicken, is a pentapeptide that protects the organism from oxidative stress by reducing the intracellular generation of reactive oxygen species. Hydrogen abstraction, a common oxidative reaction occurring in proteins, often results in the formation of d amino acid residues. To study the effect of this phenomenon on the structure of bursopentin, each of its residues were converted from the l configuration to the d configuration, and the structures of these peptide epimers were compared to that of the wild-type bursopentin. The conformations, secondary structures, compactness and hydrogen bonding of bursopentin were compared to its epimers using molecular dynamics simulations and first principles quantum chemical computations. It was discovered that the repulsion between the side chains of Lys(2) and Arg(3) influenced the conformation of the peptide regardless of the configuration of these residues. Epimerisation of the Val(4) and Tyr(5) caused a reduction in the compactness of bursopentin. In all cases, the occurrence of a turn structure was relatively high, especially when Arg(3) was in the d configuration. Thermodynamic analysis of the epimerisation process showed that the formation of d amino acid residues is favourable.
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Affiliation(s)
- A T Lam
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, CanadaM5S
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Mak SSS, Lee MY, Lee DTF, Chung TK, Au WL, Ip MH, Lam AT. Pressurised irrigation versus swabbing for wound cleansing: a multicentre, prospective, randomised controlled trial. Hong Kong Med J 2014; 20 Suppl 7:42-46. [PMID: 25647827] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Affiliation(s)
- S S S Mak
- Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong
| | - M Y Lee
- Central Nursing Department, North District Hospital, Hong Kong
| | - D T F Lee
- The Nethersole School of Nursing, The Chinese University of Hong Kong
| | - T K Chung
- Department of Medicine, Shatin Hospital, Hong Kong
| | - W L Au
- Central Nursing Department, North District Hospital, Hong Kong
| | - M H Ip
- Department of Family Medicine, New Territories East Cluster, Hospital Authority, Hong Kong
| | - A T Lam
- Department of Family Medicine, New Territories East Cluster, Hospital Authority, Hong Kong
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Abstract
Active self-assembly, in which non-thermal energy is consumed by the system to put together building blocks, allows the creation of non-equilibrium structures and active materials. Microtubule spools assembled in gliding assays are one example of such non-equilibrium structures, capable of storing bending energies on the order of 10(5) kT. Although these structures arise spontaneously in experiments, the origin of microtubule spooling has long been debated. Here, using a stepwise kinesin gradient, we demonstrate that spool assembly can be controlled by the surface density of kinesin motors, showing that pinning of microtubules due to dead motors plays a dominant role in spool initiation.
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Affiliation(s)
- A T Lam
- Department of Biomedical Engineering, 351 Engineering Terrace, 1210 Amsterdam Avenue, MC 8904, New York, NY 10027, USA.
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Twinn T, Lee A, Lam AT, Thompson DR, Cheng F, Goggins W. Effectiveness of different models of health care delivery in the primary care setting of general outpatient clinics in Hong Kong. Hong Kong Med J 2010; 16 Suppl 3:8-12. [PMID: 20601726] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Affiliation(s)
- T Twinn
- The Nethersole School of Nursing, The Chinese University of Hong Kong, Hong Kong SAR, China.
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Abstract
This prospective study evaluated four soft-tissue fixation modalities, used in seven different combinations, to reattach the tendo Achilles in 34 cadaveric specimens. Ultimate loads, elastic moduli, and modes of failure were evaluated by loading the specimen in a cantilevered fashion on an Instron. Mann-Whitney U tests were performed to compare the failure load data for statistical significance. Although the use of two Mitek SuperAnchors showed better load resistance than one anchor (p < .01), there was no significant improvement between using two or three anchors (one anchor 116 +/- 24 N, two anchors 234 +/- 21 N, three anchors 277 +/- 80 N). Two Bionx Bankart Tacks demonstrated no significant difference over using a single tack (one tack 178 +/- 57 N, two tacks 214 +/- 86 N). No statistical difference was observed between the screw and washer systems (screw with polyacetal resin washer 307 +/- 80 N, screw with metal washer 290 +/- 81 N). Both screw and washer systems did show greater stability when compared with a single Mitek SuperAnchor (p < .01) or a single Bionx Bankart Tack (p < .05). Similar analyses using the Mann-Whitney U tests were performed on the elastic modulus data. Analysis of the displacement data among all groups showed no statistical difference. Observations of the mode of failure exhibited 86% of Mitek SuperAnchor failed secondary to suture, and 70% of the Bionx Bankart Tack and 90% of the screw and washer systems failed because of the tendon shearing around the fixation. The comparisons of cost-effectiveness among the fixations showed the Synthes screw and polyacetal resin spiked washer to have the lowest cost to load ratio ($0.15/N).
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Affiliation(s)
- L Janis
- Surgical Residency Program at Grant Medical Center, Columbus, OH, USA
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Buranosky DJ, Taylor DT, Sage RA, Sartori M, Patwardhan A, Phelan M, Lam AT. First metatarsophalangeal joint arthrodesis: quantitative mechanical testing of six-hole dorsal plate versus crossed screw fixation in cadaveric specimens. J Foot Ankle Surg 2001; 40:208-13. [PMID: 11924681 DOI: 10.1016/s1067-2516(01)80020-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [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: 02/03/2023]
Abstract
Quantitative strength analysis of first metatarsophalangeal joint arthrodesis was performed using two fixation techniques: a small 6-hole plate with an interfragmentary screw or two crossed lag screws. Twelve matched-pair fresh-frozen cadaveric specimens (24 trials) were used for direct comparison of each of the two fixation techniques. All joint surfaces were prepared with power conical reamers utilizing a standard technique. The fixation construct was stressed to failure on each specimen using a computer-integrated materials tester. Fixation stiffness defined as force (load) over displacement and point of ultimate failure was evaluated. The six-hole plate and interfragmentary screw fixation method was a statistically stiffer form of fixation (p > .01) and displayed a greater point of ultimate failure (p > .002) under the laboratory conditions.
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Affiliation(s)
- D J Buranosky
- Department of Orthropaedic Surgery, Loyola University Medical Center, Maywood, IL 60153, USA
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Abstract
The purpose of this study was to evaluate the outcome of implant arthroplasty according to subjective, biomechanic, and radiographic parameters over a long period of time. Implants in 40 feet (27 patients) were analyzed at an average follow-up time of 8.25 years and a mean patient age of 63. The results were consistent with the subjective findings of previous studies that demonstrated that most patients were satisfied with the procedure. Ninety-six percent of the patients in this study confirmed they would undergo the procedure a second time. The radiographic results did not demonstrate a high incidence of implant fracture as previously reported. This review suggests that implants can be effective when used with patients who are carefully selected according to age, activity level, and diagnosis.
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Affiliation(s)
- J Bonet
- Hines Veterans Administration Medical Center, IL, USA
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Abstract
A retrospective evaluation of first metatarsophalangeal joint arthrodesis was performed on nine patients (12 feet) using two fixation techniques: a small compression plate and screws or two crossed lag screws. The joint surfaces were prepared with power conical reamers to allow for joint alignment and subsequent fusion. The average follow-up time was 6.9 months (range, 1.3 to 15 months) and, to date, all feet are successfully fused. No major postoperative complications or removal of internal fixation devices were noted in our retrospective study. This surgical technique was effective and reliable in achieving first metatarsophalangeal joint fusion, and it may serve as an alternative procedure to silicone implant or resection joint arthroplasty.
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Affiliation(s)
- R A Sage
- Department of Orthopaedic Surgery, Loyola University, Chicago, IL, USA.
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Basti MM, Stuart JW, Lam AT, Guenther R, Agris PF. Design, biological activity and NMR-solution structure of a DNA analogue of yeast tRNA(Phe) anticodon domain. Nat Struct Biol 1996; 3:38-44. [PMID: 8548453 DOI: 10.1038/nsb0196-38] [Citation(s) in RCA: 27] [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] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Design of biologically active DNA analogues of the yeast tRNA(Phe) anticodon domain, tDNAPheAC, required the introduction of a d(m5C)-dependent, Mg(2+)-induced structural transition and the d(m1G) disruption of an intra-loop dC.dG base pair. The modifications were introduced at residues corresponding to m5C-40 and wybutosine-37 in tRNA(Phe). Modified tDNAPheAC inhibited translation by 50% at a tDNAPheAC:ribosome ratio of 8:1. The molecule's structure has been determined by NMR spectroscopy and restrained molecular dynamics with an overall r.m.s.d. of 2.8 A and 1.7 A in the stem, and is similar to the tRNA(Phe) anticodon domain in conformation and dimensions. The tDNAPheAC structure may provide a guide for the design of translation inhibitors as potential therapeutic agents.
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Affiliation(s)
- M M Basti
- Department of Biochemistry, North Carolina State University, Raleigh 27695-7622, USA
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Abstract
Biologically active DNA analogs of tRNAPhe (tDNAPhe) were used to investigate metal ion interaction with tRNA-like structures lacking the 2'OH. Binding of Mg2+ to the 76 oligonucleotide tDNAPhe, monitored by circular dichroism spectroscopy, increased base stacking and thus the conformational stability of the molecule. Mg2+ binding was dependent on a d(m5C) in the anticodon region. In contrast to Mg2+, Cd2+ decreased base stacking interactions, thereby destabilizing the molecule. Since alterations in the anticodon region contributed to most of the spectral changes observed, detailed studies were conducted with anticodon hairpin heptadecamers (tDNAPheAC). The conformation of tDNAPheAC-d(m5C) in the presence of 1 mM Cd2+, Co2+, Cr2+, Cu2+, Ni2+, Pb2+, VO2+ or Zn2+ differed significantly from that of the biologically active structure resulting from interaction with Mg2+, Mn2+ or Ca2+. Nanomolar concentrations of the transition metals were sufficient to denature the tDNAPheAC-d(m5C) structure without catalyzing cleavage of the oligonucleotide. In the absence of Mg2+ and at [Cd2+] to [tDNAPheAC-d(m5C)] ratios of approximately 0.2-1.0, tDNAPheAC-d(m5C40) formed a stable conformation with one Cd2+ bound with a Kd = 3.7 x 10(-7) M. In contrast to Mg2+, Cd2+ altered the DNA analogs without discriminating between modified and unmodified tDNAPheAC. This ability of transition metals to disrupt higher order DNA structures, and possibly RNA, at microM concentrations, in vitro, demonstrates that these structures are potential targets in chronic metal exposure, in vivo.
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Affiliation(s)
- A T Lam
- Department of Biochemistry, North Carolina State University, Raleigh, USA
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