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Son YS, Lee CS, Jeong WI, Hong IH, Park SJ, Kim TH, Cho EM, Park TI, Jeong KS. Cystadenocarcinoma in the ovary of a Thoroughbred mare. Aust Vet J 2005; 83:283-4. [PMID: 15957389 DOI: 10.1111/j.1751-0813.2005.tb12740.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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102
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Sun SL, Lin CS, Zhang RQ, Lee CS, Lee ST. Calcium/Poly(9,9-dioctylfluorene) Interaction: A Theoretical Study. J Phys Chem B 2005; 109:12868-73. [PMID: 16852597 DOI: 10.1021/jp050677e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The geometric and electronic structures of poly(9,9-dioctylfluorene) (PFO) oligomer interacting with Ca atoms were studied using Møller-Plesset perturbation theory. A weak interaction with little charge transfer and with a relatively long Ca-C distance (about 4.0 Angstrom) was found when only one Ca atom was attached to a PFO unit. However, when two Ca atoms were adsorbed at a PFO unit, a strong interaction with a shorter Ca-C distance (about 2.67 Angstrom) took place with considerable charge transfer from the Ca atom to the PFO, resulting in significant deformation in the backbone of the PFO oligomer. In the latter case, the frontier orbitals of the PFO were modified. However, the deformed PFO and its modified frontier orbitals could be recovered when oxygen was added, which is in good agreement with experimental observation.
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Liu Y, Zapien JA, Shan YY, Geng CY, Lee CS, Lee ST. Wavelength-Controlled Lasing in Zn x Cd 1- x S Single-Crystal Nanoribbons. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2005; 17:1372-1377. [PMID: 34412431 DOI: 10.1002/adma.200401606] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Accepted: 02/02/2005] [Indexed: 06/13/2023]
Abstract
Znx Cd1 - x S single-crystal nanoribbons of controlled composition (where 0 ≤ x ≤ 1) can be synthesized by combining laser ablation with thermal evaporation. The nanoribbons exhibit lasing emission that can be continuously tuned within the ranges of 340-390 nm and 485-515 nm. These results suggest that Znx Cd1- x S nanoribbon lasers of pre-selected "tunable" wavelengths between 340 and 515 nm may be achievable by tailoring the value of x.
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Wang SD, Dong X, Lee CS, Lee ST. Molecular Orientation and Film Morphology of Pentacene on Native Silicon Oxide Surface. J Phys Chem B 2005; 109:9892-6. [PMID: 16852196 DOI: 10.1021/jp046490p] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The growth morphology and mechanism of pentacene films on native Si oxide surface have been studied by using high-resolution electron energy loss spectroscopy (HREELS), X-ray diffraction (XRD), and atomic force microscopy (AFM). Despite the good agreement between our own and the reported XRD results, the previous XRD interpretation that the pentacene molecules are tilt-standing on the substrate cannot explain our HREELS data. The HREELS results show that a substantial portion of the first two layers of pentacene molecules are tilted-standing or randomly oriented, whereas the upper-layer molecules are mostly lying flat to the substrate. AFM reveals that the first two layers of molecules form a flat and smooth surface, but the upper layers show a rough terrace structure with a mean-square roughness equal to the average thickness (without counting the first two layers). This relationship is explained by a theoretical model which assumes the pentacene molecules to remain on a particular molecule layer after arrival. The observed film growth morphology may have significant implication on the performance of electronic devices based on pentacene thin films. A plausible explanation was proposed for the discrepancy between the HREELS-indicated and the XRD-derived molecular orientations.
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Tse GMK, Tsang AKH, Putti TC, Scolyer RA, Lui PCW, Law BKB, Karim RZ, Lee CS. Stromal CD10 expression in mammary fibroadenomas and phyllodes tumours. J Clin Pathol 2005; 58:185-9. [PMID: 15677540 PMCID: PMC1770579 DOI: 10.1136/jcp.2004.020917] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2004] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS CD10 (CALLA) has recently been reported to be expressed in spindle cell neoplasia, and has been used to differentiate endometrial stromal sarcoma from leiomyoma and leiomyosarcoma. In the breast, myoepithelial cells express CD10, but there are few studies of the expression of CD10 in mammary fibroepithelial lesions. METHODS Stromal CD10 expression was studied in 181 mammary phyllodes tumours (102 benign, 51 borderline malignant, and 28 frankly malignant) and 33 fibroadenomas using immunohistochemistry, to evaluate whether differences in expression correlated with the degree of malignancy. RESULTS There was a progressive increase in the patients' age and tumour size, from fibroadenoma to phyllodes tumours with an increasing degree of malignancy (p < 0.001). Stromal CD10 expression was positive in one of 33 fibroadenomas, six of 102 benign phyllodes tumours, 16 of 51 borderline malignant phyllodes tumours, and 14 of 28 frankly malignant phyllodes tumours. The difference was significant (p < 0.001) and an increasing trend was established. Strong staining was seen in subepithelial areas with higher stromal cellularity and activity. Stromal CD10 expression had a high specificity (95%) for differentiating between benign lesions (fibroadenomas and benign phyllodes tumours) and malignant (borderline and frankly malignant) phyllodes tumours. CONCLUSIONS CD10 may be a useful adjunct in assessing malignancy in mammary fibroepithelial lesions.
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Kim YT, Zhao M, Kim SH, Lee CS, Kim JH, Kim JW. Prognostic significance of DNA quantification by flow cytometry in ovarian tumors. Int J Gynaecol Obstet 2005; 88:286-91. [PMID: 15733883 DOI: 10.1016/j.ijgo.2004.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 11/12/2004] [Accepted: 11/23/2004] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The objective of our study is to evaluate prognostic significance of DNA quantification by flow cytometry in ovarian tumor. METHODS A prospective analysis was performed on 56 ovarian tumor patients treated in the Yonsei Medical Center from Feb. 2000 to Jan. 2003. RESULTS Regarding the association between tumor grade and the DNA quantitative analysis, as tumor grade increased, the quantity of aneuploid cells and S-phase fraction (SPF) increased. In addition, SPF was increased significantly in the advanced staged patients (P=0.04) and SPF was significantly increased in aneuploid tumors (P=0.03). The overall survival rate was poor for patients with aneuploid tumors and for patients with tumors showing over SPF (10%). CONCLUSION Our data demonstrated that the prognosis was poor for patients with aneuploid cancers or increased SPF. Therefore, DNA quantification by flow cytometry may provide important information for predicting the prognosis of the disease.
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Oh YJ, Kim SH, Shinn HK, Lee CS, Hong YW, Kwak YL. Effects of milrinone on jugular bulb oxygen saturation and cerebrovascular carbon dioxide reactivity in patients undergoing coronary artery bypass graft surgery. Br J Anaesth 2004; 93:634-8. [PMID: 15347605 DOI: 10.1093/bja/aeh252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Jugular bulb oxygen saturation (Sjv(o(2))) is a surrogate marker for global cerebral oxygenation. The effect of milrinone on Sjv(o(2)) and the cerebrovascular carbon dioxide reactivity (CCO2R) was investigated. METHODS Thirty patients scheduled for coronary artery bypass graft surgery (CABG) were studied prospectively. After sternotomy, normoventilation (at T(1); Pa(co(2))=4.7-5.0 kPa) and hyperventilation (at T(2); Pa(co(2))=3.3-3.7 kPa) were induced and the changes in Sjv(o(2)) (DeltaSjv(o(2))) and Pa(co(2)) (DeltaPa(co(2))), and DeltaSjv(o(2))/DeltaPa(co(2)) (CCO(2)R) were measured. After normoventilation was re-established (at T(3)), milrinone 50 microg kg(-1) was given (at T(4)), followed by hyperventilation (at T(5)), and DeltaSjv(o(2)), DeltaPa(co(2)) and CCO(2)R were measured. RESULTS After milrinone administration at normoventilation (T(3) and T(4)), cardiac index and mixed venous oxygen saturation increased, while mean arterial pressure and systemic vascular resistance index decreased, without a significant change in Sjv(o(2)). Before milrinone administration (T(1) and T(2)), hyperventilation decreased Pa(co(2)) and Sjv(o(2)), and DeltaSjv(o(2)) showed positive linear correlation with DeltaPa(co(2)). After milrinone administration (T(4) and T(5)), hyperventilation decreased Pa(co(2)) and Sjv(o(2)), and DeltaSjv(o(2)) showed positive linear correlation with DeltaPa(co(2)). There was no significant difference in CCO(2)R before and after milrinone administration (13.3 (5.7)% kPa(-1) and 12.3 (3.9)% kPa(-1), respectively). CONCLUSIONS Although milrinone induced significant haemodynamic changes, Sjv(o(2)) and CCO(2)R were unchanged during its administration.
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Kim NK, Seo YW, Kim GH, Joh JH, Kim OH, Chung ER, Lee CS. A previously unreported DraI polymorphism within the regulatory region of the bovine growth hormone gene and its association with growth traits in Korean Hanwoo cattle. Anim Genet 2004; 35:152-4. [PMID: 15025585 DOI: 10.1111/j.1365-2052.2004.01100.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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109
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Abstract
Non-attendance at clinics and endoscopy units wastes resources and lengthens waiting lists. In a previous study elsewhere, a substantial proportion of patients claimed to have forgotten their appointment. We therefore assessed the value of telephoning patients a week before their booked day-case endoscopy. An observation period of two months was followed by an intervention period of two months in which patients were contacted by phone and asked if they wished to come for their investigation. A maximum of three separate attempts were made to contact each patient. Patients cancelling the appointment were replaced by others on the reserve list. The non-attendance rate was expressed as the percentage of unused beds. During the observation period 56 patients were admitted and 18 beds were unused. During the intervention period it was possible to contact 73 of 88 patients and 8 of these cancelled. 87 beds were available and 83 patients were admitted. When clerical error, overbooking and failure to replace patients were taken into account, the non-attendance rate declined from 23.3% during the observation period to 5.7% during the intervention period (P<0.05). The intervention seemed more effective in reducing non-attendance in outpatients referrals (0/48) than in general practitioner referrals (5/40).
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Chen YF, Lee CS, Lin CC, Su SF, Chen ML, Hsieh CC, Chen HM, Chiu CC, Lu YH, Liang HY, Yen HW, Hwang YS, Lin YT. Twenty-year follow-up of the Carpentier-Edwards standard porcine bioprosthesis in the Oriental population. THE JOURNAL OF CARDIOVASCULAR SURGERY 2003; 44:691-9. [PMID: 14735029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
AIM The 20-year period long-term results of porcine bioprosthetic valve use are limited. In addition, the majority of these reports come from Western countries. Given the scanty information reported in Oriental countries, this study was therefore designed to examine 20-year long-term results in patients who received a Carpentier-Edwards porcine bioprosthetic valve in an effort to contribute further information on the long-term clinical performance of porcine prosthetic valves from a viewpoint of results in the Oriental population. METHODS From July 1979 to April 2001, 82 patients received valve replacement with a standard Carpentier-Edwards porcine valve. There were 40 men and 42 women with a mean age of 42.3+/-15.1 years (range 16 to 73 years). Follow-up time extended more than 20 years (mean 10.9+/-3.2 years, range 0.5 to 21.5 years ) for a total of 719.5 patient-years. RESULTS The overall operative mortality was 16.9% (14 of 83 procedures). At 5, 10, 15, and 20 years, the actuarial survival rate of patients was 71.7%, 66.9%, 55.5%, and 44.4%, respectively. Actuarial estimates of freedom from structural valvular deterioration (SVD) at 5, 10, 15, and 17 years were 96.3%, 64.0%, 24.3%, and 24.3%, respectively; from reoperation 96.3%, 64.5%, 24.5%, and 24.5%; from operated valvular endocarditis 96.8%, 92.6%, 92.6%, and 92.6%; and from overall thromboembolism 96.3%, 88.5%, 67.2%, and 52.2%. In normal sinus rhythm, actuarial estimates of freedom from thromboembolism at 5, 10, 15, and 17 years were 100.0%, 100.0%, 81.8%, and 81.8%, respectively. Whereas for those in patients with atrial fibrillation, the estimates of freedom from thromboembolism were 94.5%, 82.4%, 57.7%, and 38.5%. CONCLUSION This study demonstrates the very satisfactory 20-year period long-term performance of freedom from bleeding events, thromboembolism (except in patients with atrial fibrillation), and valvular endocarditis in Oriental patients undergoing replacement with a porcine valve. However, the remarkable rate of SVD and reoperation ensued at 6 years after bioprosthesis implanted which does not differ from the series reported from Western countries.
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Qu Y, Vadivelu S, Choi L, Liu S, Lu A, Lewis B, Girgis R, Lee CS, Snider BJ, Gottlieb DI, McDonald JW. Neurons derived from embryonic stem (ES) cells resemble normal neurons in their vulnerability to excitotoxic death. Exp Neurol 2003; 184:326-36. [PMID: 14637103 DOI: 10.1016/j.expneurol.2003.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We determined whether embryonic stem (ES) cells could provide a model system for examining neuronal death mediated by glutamate receptors. Although limited evidence indicates that normal neurons can be derived from mouse ES cells, there have been no studies examining pathophysiological responses in mouse ES cell systems. Mouse ES cells, induced down a neural lineage by retinoic acid (RA), were found to have enhanced long-term survival when plated onto a layer of cultured mouse cortical glial cells. In these conditions, the ES cells differentiated into neural cells that appeared normal morphologically and displayed normal features of immunoreactivity when tested for neuron-specific elements. Varying the culture medium generated cultures of mixed neuronal/glial cells or enriched in oligodendrocytes. These cultures were viable for at least four weeks. Real-time PCR analysis of N-methyl-D-aspartate (NMDA) receptor subunits revealed an appropriate age-in-vitro dependent pattern of expression. Neurons derived from ES cells were vulnerable to death induced by a 24-h exposure to the selective glutamate receptor agonists NMDA, kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). This vulnerability to agonist-induced death increased with age in vitro, and related closely to expression of receptor subunits, as it does in cultured primary neurons. Experiments with selective receptor antagonists showed that glutamate receptors mediated the NMDA- and kainate-induced death. Neuronal differentiated ES cells therefore exhibited an excitotoxic response resembling that displayed by central nervous system (CNS) neurons. Thus, ES cells, which are very amenable to genetic manipulation, provide a valid system for studying glutamate receptor-mediated toxicity at the molecular level.
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Noh DH, Jeong WI, Lee CS, Jung CY, Chung JY, Jee YH, Do SH, An MY, Kwon OD, Williams BH, Jeong KS. Multiple Congenital Malformation in a Holstein Calf. J Comp Pathol 2003; 129:313-5. [PMID: 14554130 DOI: 10.1016/s0021-9975(03)00044-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A 10-day-old male Holstein dairy calf with orthopaedic abnormalities was unable to stand but was alert with a suckle reflex. At necropsy, the calf showed multiple defects, including partial agenesis of the left rib plate, deformed left scapula, shortened left humerus, agenesis of the left kidney, atresia ani and scoliosis. The cause of these anomalies could not be determined. This report is the first to describe partial agenesis of ribs in a calf.
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Abstract
Non-attendance at clinics and endoscopy units wastes resources and lengthens waiting lists. In a previous study elsewhere, a substantial proportion of patients claimed to have forgotten their appointment. We therefore assessed the value of telephoning patients a week before their booked day-case endoscopy. An observation period of two months was followed by an intervention period of two months in which patients were contacted by phone and asked if they wished to come for their investigation. A maximum of three separate attempts were made to contact each patient. Patients cancelling the appointment were replaced by others on the reserve list. The non-attendance rate was expressed as the percentage of unused beds. During the observation period 56 patients were admitted and 18 beds were unused. During the intervention period it was possible to contact 73 of 88 patients and 8 of these cancelled. 87 beds were available and 83 patients were admitted. When clerical error, overbooking and failure to replace patients were taken into account, the non-attendance rate declined from 23.3% during the observation period to 5.7% during the intervention period (P<0.05). The intervention seemed more effective in reducing non-attendance in outpatients referrals (0/48) than in general practitioner referrals (5/40).
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Stoessl AJ, Lee CS, de la Fuente-Fernandez R. New concepts and tools in imaging for the study of neurodegenerative disease. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2003:157-66. [PMID: 12946054 DOI: 10.1007/978-3-7091-0643-3_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Existing technologies permit the detection of changes in neurotransmitter and/or neuroreceptor expression. This may be useful for diagnosis, for monitoring disease progression, and for assessing the pathogenesis of complications associated with long-term treatment. Although the binding of [11C]raclopride to D2 receptors is subject to competition from endogenous dopamine, this can be exploited to estimate changes in synaptic levels of dopamine. Assessment of processes downstream to the receptor will require the development of new approaches.
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Lee CS, Han JH, Kim BS, Lee SM, Hwang JS, Kang SW, Lee BH, Kim HR. Wax moth, Galleria mellonella, high density lipophorin receptor: alternative splicing, tissue-specific expression, and developmental regulation. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:761-771. [PMID: 12878223 DOI: 10.1016/s0965-1748(03)00066-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A lipophorin (Lp) receptor cDNA from the fat body of Galleria mellonella (Lepidoptera) was cloned and sequenced. This is the first result in this order, Lepidoptera. It showed the pattern of the VLDL receptor belonging to the LDL receptor family. Sequence homology with other Lp receptors in insects, Locusta migratoria and Aedes aegypti, was 70 and 61%, respectively and each domain was highly conserved. Polyclonal anti-Lp receptor antibody prepared against expressed Lp receptor fragment between ligand binding domain and EGF-precursor homology domain (R305-D549 of amino acid residues) specifically detected the Lp receptor. Through immuno-blotting, the Lp receptor of larval fat body has an approximate molecular mass of about 97 and 110 kDa under non-reducing and reducing conditions, respectively. This result was in agreement with that of the ligand-blotting. The variant Lp receptors were expressed in the fat body of G. mellonella; one is an Lp receptor which lacks 84 bp of O-linked sugar domain and the other is a full length form of the Lp receptor. Both forms were detected by the polyclonal anti-Lp receptor antibody. The Lp receptor from the fat body of G. mellonella was differently expressed depending on the tissue and the developmental stage with specific abundance in prepupal stage. A steroid hormone, 20-hydroxyecdysone (20-HE) plays a crucial role in insect development. With regards to this conception, day 1-2 last instar larvae were treated with 20-HE and drastic induction of the Lp receptor was observed 48 h after treatment. It was also observed that cholesterol caused an induction of the Lp receptor.
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Chu PY, Wright PJ, Lee CS. Apoptosis of endometrial cells in the bitch. Reprod Fertil Dev 2003; 14:297-305. [PMID: 12467354 DOI: 10.1071/rd01108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Accepted: 07/10/2002] [Indexed: 11/23/2022] Open
Abstract
The relationship between apoptosis of endometrial cells in the bitch, and the occurrence of degeneration of the endometrial luminal epithelium and regression of the endometrial glandular epithelium was determined. Mature bitches (n = 12) were ovariectomized and treated with hormones to simulate uterine changes that occur during the oestrous cycle. All bitches were treated with oestradiol benzoate (0.6-4.8 microg x kg(-1), i. m., twice per day) for 11-12 days then with progestagen (megestrol acetate, 2 mg x kg(-1), p. o., once per day) for 35-37 days. Bitches were treated daily for a further 3 weeks with megestrol acetate at dose rates of 0.5 mg x kg(-1) (decreased-dose group (n = 3)), 2 mg x kg(-1) (standard-dose group (n = 3)), or 3 (1 wk), 4 (1 wk) and 5 (1 wk) mg x kg(-1) (increased-dose group (n = 3)), or received no treatment (withdrawal-dose group (n = 3)). These bitches were necropsied at the end of the treatment period. A further 10, ovary-intact, bitches were necropsied when in oestrus (n = 1), dioestrus (n = 5), and at 3 weeks (n = 1) and 9 weeks (n = 3) of anoestrus. Degeneration of the luminal epithelium was observed in all bitches except those in oestrus, at 9 weeks of anoestrus and one in dioestrus. Apoptosis was observed in the glandular epithelial cells, stromal cells and endothelial cells of blood capillaries in all bitches except those at oestrous and at 9 weeks of anoestrous. High average apoptotic indices were detected in the basal glandular epithelium of the dioestrous, decreased-dose, standard-dose and increased-dose groups, whereas low apoptotic indices were detected at 3 weeks of anoestrous and in the withdrawal-dose groups. These results indicate that degeneration of cells of the glandular epithelium, but not of the luminal epithelium, was due to apoptosis of these cells.
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Abstract
Small-diameter (1 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (111)-(1 x 1) and Si (001)-(1 x 1) surfaces corresponding to SiH3 on Si (111) and SiH2 on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.
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Kubono S, Abe K, Kato S, Teranishi T, Kurokawa M, Liu X, Imai N, Kumagai K, Strasser P, Tanaka MH, Fuchi Y, Lee CS, Kwon YK, Lee L, Ha JH, Kim YK. Determination of the subthreshold state contribution in 13C(alpha,n)16O, the main neutron-source reaction for the s process. PHYSICAL REVIEW LETTERS 2003; 90:062501. [PMID: 12633289 DOI: 10.1103/physrevlett.90.062501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2002] [Indexed: 05/24/2023]
Abstract
The reaction rate of the stellar reaction 13C(alpha,n)16O, which is currently considered to be the main neutron source for the slow (s) process at low energies, has been rederived using the direct alpha-transfer reaction 13C(6Li,d)17O leading to the subthreshold state at 6.356 MeV in 17O. The contribution of the subthreshold state is found to be much smaller than the currently accepted predictions for the main neutron source of the s process, indicating less of a role of this reaction as the neutron source for the s-process scenario in low-mass stars at the asymptotic giant branch.
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Clarke RA, Fang ZH, Marr PJ, Lee CS, Kearsley JH, Papadatos G. ATM induction insufficiency in a radiosensitive breast-cancer patient. AUSTRALASIAN RADIOLOGY 2002; 46:329-35. [PMID: 12196249 DOI: 10.1046/j.1440-1673.2002.01072.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ataxia telangiectasia (A-T) gene (ATM) is a dominant breast cancer gene with tumour suppressor activity. ATM also regulates cellular sensitivity to ionising radiation (IR) presumably through its role as a facilitator of DNA repair. In normal cells and tissues the ATM protein is rapidly induced by IR to threshold/maximum levels. The kinase function of the ATM protein is also rapidly activated in response to IR. The fact that women carriers of ATM mutations can have an increased risk of developing breast cancer and that many sporadic breast tumours have reduced levels of the ATM protein broadens the scope of ATM's tumour suppressor within the breast. This report describes the downregulation of ATM protein levels in a radiosensitive breast cancer patient. Postinduction ATM levels were up to tenfold lower in the patient's fresh tissues compared to normal controls. These results might indicate a much broader role for ATM anomalies in breast cancer aetiology.
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Sun XH, Li CP, Wong NB, Lee CS, Lee ST, Teo BK. Reductive growth of nanosized ligated metal clusters on silicon nanowires. Inorg Chem 2002; 41:4331-6. [PMID: 12184748 DOI: 10.1021/ic011219x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reductive growth of metal clusters on silicon nanowires (SiNWs) is reported. The HF-etched SiNWs were found to reduce ligated Au-Ag clusters of single size, shape, composition, and structure. In the process, the surfaces of the SiNWs were reoxidized. The reductive cluster growth on the SiNW surface was followed by high-resolution transmission electron microscopy (HRTEM). The reduced metal clusters grew to different sizes in the nanometer regime (1-7 nm in diameter) on the SiNW surfaces. At sizes greater than approximately 7 nm, they tend to separate from the SiNW surfaces. Further growth and/or agglomeration of these colloidal particles to sizes greater than roughly 25 nm in diameter eventually causes the particles to precipitate from solution. Two interesting phenomena, the "sinking cluster" and the "cluster fusion" processes, were observed under TEM.
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Fetherston CM, Lee CS, Hartmann PE. Mammary gland defense: the role of colostrum, milk and involution secretion. ADVANCES IN NUTRITIONAL RESEARCH 2002; 10:167-98. [PMID: 11795040 DOI: 10.1007/978-1-4615-0661-4_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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Putti TC, To KF, Hsu HC, Chan ATC, Lai GM, Tse G, Lee YS, Whang-Peng J, Millward M, Lin L, Lin X, Lee CS. Expression of epidermal growth factor receptor in head and neck cancers correlates with clinical progression: a multicentre immunohistochemical study in the Asia-Pacific region. Histopathology 2002; 41:144-51. [PMID: 12147092 DOI: 10.1046/j.1365-2559.2002.01436.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS With ongoing efforts to target the epidermal growth factor receptor (EGFR)-mediated tumour growth in the treatment of selected human malignancies, there is a need to determine the expression levels of EGFR and to evaluate its prognostic value in various malignancies in the Asia-Pacific region. METHODS AND RESULTS A total of 172 patients with head and neck squamous cell carcinomas from Australia, Hong Kong, Singapore, and Taiwan were selected for EGFR detection. Immunohistochemical staining was performed to evaluate EGFR expression. EGFR expression was present in 88.4% (152/172) of all cases tested. Specifically, EGFR expression was found in 91.3% (42/46), 84.6% (22/26), 84.1% (37/44), 96.0% (24/25), and 87.1% (27/31) cases of head and neck squamous cell carcinomas from the oral cavity, oropharynx, nasopharynx, hypopharynx, and larynx, respectively. The results demonstrate a stronger EGFR expression in T4 tumours (P=0.017) and later clinical stages (P=0.016). No significant correlation was seen with risk factors, primary tumour site and ethnicity. CONCLUSIONS The majority of head and neck squamous cell carcinomas express EGFR, indicating the importance of studying the efficacy of anti-cancer therapy through this pathway. The results also show similar rates of receptor expression in head and neck squamous cell carcinoma patients from our region compared with other parts of the world.
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Haghighat F, Lee CS, Ghaly WS. Measurement of diffusion coefficients of VOCs for building materials: review and development of a calculation procedure. INDOOR AIR 2002; 12:81-91. [PMID: 12216471 DOI: 10.1034/j.1600-0668.2002.1e008.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The measurement and prediction of building material emission rates have been the subject of intensive research over the past decade, resulting in the development of advanced sensory and chemical analysis measurement techniques as well as the development of analytical and numerical models. One of the important input parameters for these models is the diffusion coefficient. Several experimental techniques have been applied to estimate the diffusion coefficient. An extensive literature review of the techniques used to measure this coefficient was carried out, for building materials exposed to volatile organic compounds (VOC). This paper reviews these techniques; it also analyses the results and discusses the possible causes of difference in the reported data. It was noted that the discrepancy between the different results was mainly because of the assumptions made in and the techniques used to analyze the data. For a given technique, the results show that there can be a difference of up to 700% in the reported data. Moreover, the paper proposes what is referred to as the mass exchanger method, to calculate diffusion coefficients considering both diffusion and convection. The results obtained by this mass exchanger method were compared with those obtained by the existing method considering only diffusion. It was demonstrated that, for porous materials, the convection resistance could not be ignored when compared with the diffusion resistance.
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Chen LJ, Lai JB, Lee CS. High-resolution transmission electron microscopy of phase formation and growth in metal-Si-Ge systems. Micron 2002; 33:535-41. [PMID: 12020698 DOI: 10.1016/s0968-4328(02)00008-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
High-resolution transmission electron microscopy (HRTEM) in conjunction with nano-beam (NB) analysis as well as energy dispersive spectrometry analysis have been fruitfully utilized to study the interfacial reactions in the metal-Si-Ge systems. In this paper we report the results of TEM study of the phase formation and growth in Ti-Si-Ge, Cu-Si-Ge and Ni-Si-Ge systems.
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Lee CS, Hartley JA, Berardini MD, Butler J, Siegel D, Ross D, Gibson NW. Alteration in DNA cross-linking and sequence selectivity of a series of aziridinylbenzoquinones after enzymic reduction by DT-diaphorase. Biochemistry 2002; 31:3019-25. [PMID: 1372518 DOI: 10.1021/bi00126a025] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DT-diaphorase (DTD) mediated reduction of a series of 2,5-bis-substituted-3,6-diaziridinyl-1,4-benzoquinones was found to increase the level of DNA interstrand cross-linking (ISC) formed at neutral pH with an enhancement observed as the pH was decreased to 5.8. The analogues used were symmetrically alkyl-substituted carbamoyl ester analogues of AZQ (D1-D7), 3,6-diaziridinyl-1,4-benzoquinone (DZQ), the 2,5-dimethyl derivative (MeDZQ), and a 2,5-bis[(2-hydroxyethyl)amino] analogue (BZQ). At pH 5.8, the level of DNA ISC induced by enzymatic reduction was as follows: DZQ greater than MeDZQ much greater than D1 (methyl) greater than D3 (n-propyl) greater than D2 (AZQ; ethyl) greater than D5 (n-butyl) greater than D7 (sec-butyl) greater than D4 (isopropyl) D6 greater than (isobutyl). A similar trend was observed at pH 7.2. The level of DNA ISC induced by BZQ, which is not a substrate for DTD, was not increased by enzymatic reduction. Dicumarol, a known inhibitor of DTD, was capable of inhibiting the DNA ISC induced by these quinones upon enzymatic reduction. MeDZQ and DZQ reacted with guanines, as measured by Maxam and Gilbert sequencing, with a sequence selectivity similar to that of the nitrogen mustard class of antitumor agents. Enzymatic reduction of DZQ and MeDZQ by DTD was found to alter their sequence-selective alkylation. Reduced DZQ showed enhanced guanine alkylation in 5'-GC-3' sequences and new sites of adenine alkylation in 5'-(A/T)AA-3' sequences. Reduced MeDZQ only showed new sites of adenine alkylation at 5'-(A/T)AA-3' sequences but no enhancement of guanine alkylation. The new sites of adenine alkylation were found to be inhibited in the presence of magnesium and rapidly converted into apurinic sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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