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Yang KH, Park SJ. Stimulation of fracture healing in a canine ulna full-defect model by low-intensity pulsed ultrasound. Yonsei Med J 2001; 42:503-8. [PMID: 11675678 DOI: 10.3349/ymj.2001.42.5.503] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Because no report has been issued on the healing effects of low-intensity pulsed ultrasound on moderate to large fracture gaps, we performed an experimental study using a canine ulna full-defect model. Ten mongrel male dogs were divided into two groups: a small defect group and large defect group. The defects were made on the middle one third of both ulnae and one side only was randomly selected for ultrasound sonication, at 1 MHz, 200 microsecond bursting sine wave in 50 mW/cm2 spacial average and temporal average. Sonication was started on the day after surgery and applied for 15 minutes once a day for six days a week. In the small defect group, the means of the radiologic scores, as described by Lane and Sandhu, were 0.6, 4.4, and 8.4 in the control side and 1.8, 6.0, and 10.4 in the treatment side one, three, and five months after the operation, respectively (p=0.0372). In the large defect model, the corresponding means were 2.2, 3.4, and 6.0 in the control side and 3.3, 5.4, and 9.2 in the treatment side (p= 0.009). Low-intensity pulsed ultrasound enhanced new bone formation in small and large full-defects and decreased the incidence of nonunion in the large defect model.
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Na YJ, Jeon YJ, Suh JH, Kang JS, Yang KH, Kim HM. Suppression of IL-8 gene expression by radicicol is mediated through the inhibition of ERK1/2 and p38 signaling and negative regulation of NF-kappaB and AP-1. Int Immunopharmacol 2001; 1:1877-87. [PMID: 11562079 DOI: 10.1016/s1567-5769(01)00113-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We show that radicicol, an anti-fungal agent, inhibits interleukin-8 (IL-8) production by the human monocyte line THP-1 in response to phorbol-12-myristate-13-acetate/lipopolysaccharide (PMA/LPS). IL-8 is a potent chemokine and needs for an optimal immune response--such as inflammation by activation of neutrophils. The decrease in PMA/LPS-induced IL-8 mRNA expression was demonstrated by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Since the promoter in IL-8 gene contains binding motifs for NF-KB, AP-1. and NF-IL6, which appear to be important in IL-8 induction, the effects of radicicol on the activation of these transcription factors were examined. Treatment of radicicol to THP-1 cells produced a strong inhibition of NF-KB and AP-1, while NF-IL6 was not significantly affected by radicicol. Western blot analysis showed that radicicol inhibited the phosphorylation and phosphotransferase activities of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38. PD98059 and SB203580, known as a specific inhibitor of MEKI and p38 kinase, respectively, inhibited IL-8 gene expression showing that both of the kinase pathways are involved in IL-8 regulation in human monocytes. Collectively, this series of experiments indicates that radicicol inhibits IL-8 gene expression by blocking ERK1/2 and p38 signaling.
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Kim DS, Choi JU, Yang KH, Park CI. Selective posterior rhizotomy in children with cerebral palsy: a 10-year experience. Childs Nerv Syst 2001; 17:556-62. [PMID: 11585331 DOI: 10.1007/s003810100465] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We reviewed our 10-year experience of selective posterior rhizotomy (SPR), with an emphasis on surgical outcome concentrated on improvements in functional ability and adverse effects. We had performed SPR in 208 patients between 1990 and 1999. All patients showed an overall improvement (over 95%) in spasticity, passive range of motion, and gait pattern. Preoperative ambulatory functional level and age were very important predictive factors for further improvements in postoperative functional ability. Compared with the younger children, the older ones lacked a full range of motion preoperatively, and they continued to lack a full range of motion postoperatively, despite the decrease in tone achieved by SPR. Most postoperative complications such as hypotonia, urinary retention, spinal deformities, and sensory changes were temporary and not functionally important. We conclude that SPR is an effective method of alleviating spasticity and provides lasting functional benefits at acceptable complication levels in spastic children with cerebral palsy.
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Choi NK, Yang KH. A study on the eruption timing of primary teeth in Korean children. ASDC JOURNAL OF DENTISTRY FOR CHILDREN 2001; 68:244-9, 228. [PMID: 11862875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The objectives of this study were to clarify the eruption time and sequence of primary teeth in Korean children. A random sample of 1070 children from ages of four to thirty-six months was examined: 567 were males and 503 were females. The median values to measure the eruption time of the primary teeth were used. The results show that the primary teeth of boys erupt earlier than those of girls. As to the eruption sequence of primary teeth, the mandibular central incisor and second molar erupted earlier than their maxillary counterparts. For the lateral incisor, the canine and the first molar, the maxillary teeth erupted before the mandibular ones.
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Lee SK, Kim YS, Oh HS, Yang KH, Kim EC, Chi JG. Prenatal development of the human mandible. THE ANATOMICAL RECORD 2001; 263:314-25. [PMID: 11455541 DOI: 10.1002/ar.1110] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In an effort to better understand the interrelationship of the growth and development pattern of the mandible and condyle, a sequential growth pattern of human mandibles in 38 embryos and 111 fetuses were examined by serial histological sections and soft X-ray views. The basic growth pattern of the mandibular body and condyle appeared in week 7 of fertilization. Histologically, the embryonal mandible originated from primary intramembranous ossification in the fibrous mesenchymal tissue around the Meckel cartilage. From this initial ossification, the ramifying trabecular bones developed forward, backward and upward, to form the symphysis, mandibular body, and coronoid process, respectively. We named this initial ossification site of embryonal mandible as the mandibular primary growth center (MdPGC). During week 8 of fertilization, the trabecular bone of the mandibular body grew rapidly to form muscular attachments to the masseter, temporalis, and pterygoid muscles. The mandible was then rapidly separated from the Meckel cartilage and formed a condyle blastema at the posterior end of linear mandibular trabeculae. The condyle blastema, attached to the upper part of pterygoid muscle, grew backward and upward and concurrent endochondral ossification resulted in the formation of the condyle. From week 14 of fertilization, the growth of conical structure of condyle became apparent on histological and radiological examinations. The mandibular body showed a conspicuous radiating trabecular growth pattern centered at the MdPGC, located around the apical area of deciduous first molar. The condyle growth showed characteristic conical structure and abundant hematopoietic tissue in the marrow. The growth of the proximal end of condyle was also approximated to the MdPGC on radiograms. Taken together, we hypothesized that the MdPGC has an important morphogenetic affect for the development of the human mandible, providing a growth center for the trabecular bone of mandibular body and also indicating the initial growth of endochondral ossification of the condyle.
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Abstract
STUDY DESIGN A finite element parametric study was performed to investigate the structural roles of the vertebral cortical shell and the trabecular centrum. OBJECTIVES To address the debated issue of the relative load-carrying role of the vertebral cortical shell. SUMMARY OF BACKGROUND DATA Several experimental and computational studies have been aimed at quantifying the load-carrying roles of the human vertebral cortical shell and trabecular centrum. These studies, however, have supported no consensus. METHODS A finite element model of three lumbar vertebral bodies was developed to predict the fraction of the total compressive load acting on the lumbar vertebral body, under two different loading conditions, that was supported by the cortical shell. Parametric variations in vertebral material and geometric properties were examined to determine how this fraction was influenced by such changes. RESULTS The fraction of the compressive load supported by the cortical shell was found to be strongly dependent on the distance from the endplate, increasing from about 34% at either endplate to approximately 63% at the midtransverse plane. This fraction was independent of the loading characteristics, proportional to the properties of the cortex, and inversely proportional to the modulus of the centrum. Additionally, the cortical shell force fraction was affected significantly by changes in the overall vertebral geometry. CONCLUSIONS Our findings indicate that the structural dominance of the cortical shell and centrum alternate depending on the location within the vertebral body. However, as age-related bone loss progresses, the load-carrying role of the cortical shell could increase significantly.
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Abstract
SUMMARY The authors report a case of acetabular fracture of both columns that was associated with a rare nerve injury, entrapment of the obturator nerve in the hip joint.
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133
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Yea SS, Kim HM, Oh HM, Paik KH, Yang KH. Microcystin-induced down-regulation of lymphocyte functions through reduced IL-2 mRNA stability. Toxicol Lett 2001; 122:21-31. [PMID: 11397554 DOI: 10.1016/s0378-4274(01)00339-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we report that lymphocyte functions were down-regulated by cyanobacterial hepatotoxin microcystin. Treatment of three microcystin (MC) isotypes, MC-LR, MC-YR and nodularin, on B6C3F1 mouse splenocytes produced dose-dependent inhibition of in vitro polyclonal antibody response and lymphoproliferation to LPS. ConA-induced lymphoproliferative response was decreased by MC-YR and nodularin, but no significant effect was observed in the MC-LR treatment. Intraperitoneal administration of nodularin into B6C3F1 mice decreased humoral immune responses to sheep red blood cell (sRBC), and the inhibitory effect became severe when hepatic uptake of nodularin was blocked by rifampicin. Each MC 1 microM suppressed phorbol 12-myristate 13-acetate (PMA) plus ionomycin-induced IL-2 mRNA expression in splenocytes and thymocytes, but not in EL-4 mouse thymoma cells. To further characterize the mechanism for the reduced IL-2 mRNA level, IL-2 mRNA stability was measured using RT-PCR. Deprivation of PMA/ionomycin stimuli from activated splenocytes and blockade of new transcription resulted in destabilization of IL-2 mRNA, which was accelerated by MC treatment. These results demonstrated that MC down-regulated lymphocyte functions and the immunosuppression was mediated, at least in part, through decreased IL-2 mRNA stability.
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Yu YW, Tsai SJ, Yang KH, Lin CH, Chen MC, Hong CJ. Evidence for an association between polymorphism in the serotonin-2A receptor variant (102T/C) and increment of N100 amplitude in schizophrenics treated with clozapine. Neuropsychobiology 2001; 43:79-82. [PMID: 11174050 DOI: 10.1159/000054871] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Using event-related potentials (ERPs), a reduction in the auditory N100, N200 and P300 amplitude has been found in schizophrenic patients and may represent some pathophysiological deficit. Therefore, we investigated whether the genetic variant of the serotonin-2A receptor is associated with ERP change after clozapine treatment in schizophrenic patients. Ninety-nine schizophrenic patients were included in the study. The results demonstrated that patients with 102C/C genotype have higher N100 amplitude than other patients after clozapine treatment. Our findings suggested that serotonin-2A receptor polymorphism may relate to clozapine response in schizophrenic patients. An objective and reliable tool like ERPs to assess patients' treatment response may afford more consistent results in pharmacogenetic studies.
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Chaudhari P, Lacey J, Doyle J, Galligan E, Lien SC, Callegari A, Hougham G, Lang ND, Andry PS, John R, Yang KH, Lu M, Cai C, Speidell J, Purushothaman S, Ritsko J, Samant M, Stöhr J, Nakagawa Y, Katoh Y, Saitoh Y, Sakai K, Satoh H, Odahara S, Nakano H, Nakagaki J, Shiota Y. Atomic-beam alignment of inorganic materials for liquid-crystal displays. Nature 2001; 411:56-9. [PMID: 11333974 DOI: 10.1038/35075021] [Citation(s) in RCA: 351] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The technique used to align liquid crystals-rubbing the surface of a substrate on which a liquid crystal is subsequently deposited-has been perfected by the multibillion-dollar liquid-crystal display industry. However, it is widely recognized that a non-contact alignment technique would be highly desirable for future generations of large, high-resolution liquid-crystal displays. A number of alternative alignment techniques have been reported, but none of these have so far been implemented in large-scale manufacturing. Here, we report a non-contact alignment process, which uses low-energy ion beams impinging at a glancing angle on amorphous inorganic films, such as diamond-like carbon. Using this approach, we have produced both laptop and desktop displays in pilot-line manufacturing, and found that displays of higher quality and reliability could be made at a lower cost than the rubbing technique. The mechanism of alignment is explained by adopting a random network model of atomic arrangement in the inorganic films. Order is induced by exposure to an ion beam because unfavourably oriented rings of atoms are selectively destroyed. The planes of the remaining rings are predominantly parallel to the direction of the ion beam.
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Tsai SJ, Wang YC, Yu Younger WY, Lin CH, Yang KH, Hong CJ. Association analysis of polymorphism in the promoter region of the alpha2a-adrenoceptor gene with schizophrenia and clozapine response. Schizophr Res 2001; 49:53-8. [PMID: 11343863 DOI: 10.1016/s0920-9964(00)00127-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
There exists considerable evidence implicating the alpha (alpha) adrenergic system in the superior therapeutic effects of clozapine for the treatment of schizophrenia, as also its associated adverse hypersalivation side effect. It would seem plausible for variants of the adrenoceptors to be associated with the clozapine response. The present study tested the hypothesis that a biallelic polymorphism in the promoter region of the alpha2a-adrenoceptor gene confers susceptibility to schizophrenia, and is associated with a clozapine-induced (favorable) therapeutic response and/or a clozapine-induced hypersalivation. Ninety-seven treatment-resistant schizophrenic patients were assessed using the Brief Psychiatric Rating Scale before and after clozapine treatment. The results of clozapine treatment demonstrated that the alpha2a-adrenoceptor gene variants did not play a major role in the susceptibility, hypersalivation adverse effect or clozapine response of patients with schizophrenia. The polymorphism of the alpha2a-adrenoceptor gene investigated is not likely to play a major role in the pathogenesis of schizophrenic disorders or clozapine response, although the hypothesis that these genes are implicated in the cognitive deficit and polydipsia associated with schizophrenic disorders may, however, still warrant further study.
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Koo MW, Yang KH, Begeman P, Hammami M, Koo WW. Prediction of bone strength in growing animals using noninvasive bone mass measurements. Calcif Tissue Int 2001; 68:230-4. [PMID: 11353950 DOI: 10.1007/s002230010006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2000] [Accepted: 11/20/2000] [Indexed: 10/26/2022]
Abstract
This study aims to test the hypothesis that noninvasive bone mass measurements can be used to predict bone strength in a piglet model. Dual energy X-ray absorptiometry measurements of bone mineral content (BMC), bone mineral density (BMD), and bone area (BA) were obtained from four sets of bones (left and right humeri and femora) of 12 piglets (6-68 days and 2250-17660 g). Bone strength, defined by the energy to bone failure, fracture moment, and flexural rigidity, was determined from three point bending tests using an Instron material testing system. Results show that bone mass between left and right extremities was highly correlated (r = 0.96 to 0.99, P < or 0.001 all comparisons) and was similar for bone strength (r = 0.85 to 0.98, P < 0.01 all comparisons). However, based on the standard deviation of the difference between measurements from left and right extremities, the agreement sides was better for bone mass than for bone strength measurements (r = 0.68-0.99, P < = 0.05-< or = 0.001). The predictive ability of bone mass on bone strength varied (adjusted r2 = 0.41-0.97) depending on the bone tested and the measurement parameter used, although remained statistically significant in all instances (P < 0.05-< or = 0.001). We conclude that the developing organisms, noninvasive bone mass measurements are correlated with and predictive of bone strength, although bones from the same side and same anatomical site should be used for comparison purposes.
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Lin CH, Tsai SJ, Yu YW, Yang KH, Hsu CP, Hong CJ. Study of anticipation in Chinese families with schizophrenia. Psychiatry Clin Neurosci 2001; 55:137-40. [PMID: 11285093 DOI: 10.1046/j.1440-1819.2001.00801.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The anticipation phenomenon is an important aspect in several genetic disorders in which the age at onset (AAO) decreases and the severity of illness increases in successive generations. This phenomenon has been reported in several schizophrenic family studies, and expanded repeat mutations are implicated. In the present study, we investigate the anticipation phenomenon in Chinese schizophrenic families. We compare the AAO between two generations of 38 unilinear schizophrenic families. Intergenerational comparisons show that the AAO was significantly earlier in the offspring generation (mean AAO, 22.2 years) than that in the parental generation (mean AAO, 31.0 years) (P < 0.001). When only including the offspring generation who married, the AAO difference between the two generations was not significant (28.4 years vs 31.0 years, P = 0.151). Our findings suggest that a selection bias in the parental group might greatly impact the study of anticipation in schizophrenia. Other unavoidable biases associated with these analyses are discussed in the text.
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Hong CJ, Lin CH, Yu YW, Yang KH, Tsai SJ. Genetic variants of the serotonin system and weight change during clozapine treatment. PHARMACOGENETICS 2001; 11:265-8. [PMID: 11337942 DOI: 10.1097/00008571-200104000-00010] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Clozapine-induced weight gain may impair health and affect patient compliance. The aim of this study is to investigate the relationship between the genetic variants of the serotonin system and clozapine-induced body weight change (BWC). Ninety-three treatment-resistant schizophrenic patients were weighed monthly for 4 months during clozapine treatment. At the conclusion of treatment, patients had gained an average of 2.4 kg body weight, with BWC ranging from -17.5 to +12.9 kg. The levels of the serotonin transporter variants, serotonin 2A, serotonin 2C and serotonin 6, demonstrated no statistically significant relationship to BWC. Patients with a lower initial body mass index demonstrated a greater weight gain associated with clozapine treatment. Further exploration of the neurotransmitters implicated in the antipsychotic-induced BWC is important in order to reduce the morbidity and noncompliance associated with weight gain.
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Ala TA, Yang KH, Sung JH, Frey WH. Clinical parkinsonism in dementia patients with substantia nigra Lewy bodies. J Neural Transm (Vienna) 2001; 106:47-57. [PMID: 10195334 DOI: 10.1007/s007020050140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In a retrospective clinicopathological study, we examined the substantia nigra (SN) of 48 dementia patients with SN Lewy bodies (LBs) to determine if the severity of degeneration correlated with either the occurrence of signs of parkinsonism at dementia presentation or with the frequency of treatment for parkinsonism during the disease course. The SN specimens were graded for microscopic degeneration using a semi-quantitative five-tiered scale. Whereas no correlation was found between the grade of degeneration and occurrence of signs at presentation (r = -0.16, p = 0.18), with 16 of 38 patients having had signs reported, a more severe grade was statistically correlated with an increased frequency of treatment during the course (r = 0.41, p = 0.004), with ten of 41 patients having been treated for parkinsonism. Contrary to our expectations, we found that fewer than half of the patients with the two most severe grades of degeneration presented with signs of parkinsonism or were ever treated for parkinsonism.
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141
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Hong CJ, Yu YW, Lin CH, Song HL, Lai HC, Yang KH, Tsai SJ. Association study of apolipoprotein E epsilon4 with clinical phenotype and clozapine response in schizophrenia. Neuropsychobiology 2001; 42:172-4. [PMID: 11096331 DOI: 10.1159/000026689] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Schizophrenic patients with the apolipoprotein E (APOE = gene; apoE = protein) epsilon4 allele exhibited lower psychosis scores than patients without the epsilon4 allele in previous reports. The present study tested the hypothesis that the APOE epsilon4 allele confers association with the clinical manifestations of schizophrenia or clozapine response. A total of 95 schizophrenic patients who were treatment resistant were included in the study. The results demonstrated that the presence of the APOE epsilon4 allele did not influence the response to clozapine in schizophrenic patients, neither was the baseline psychopathology related to the APOE epsilon4 allele. Given the multiple functions of the apoE protein in the brain, further study of the influence of APOE on CNS medication response is needed.
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Abstract
This paper reviews the traditional areas of impact biomechanics as they relate to brain injury caused by blunt impact. These areas are injury mechanisms, human response to impact, human tolerance to impact and the use of human surrogates. With the advent of high-speed computers, it is now possible to add computer models to the list of human surrogates that used to be limited to animals and human cadavers. The advantages and shortcomings of current computer models are discussed. One of the computer models was used to predict the pressures and shear stresses developed in the brain and the extent of stretch of the bridging veins in the brains of American football players who sustained severe helmet-to-helmet head impact during the game. It was found that increases in intracranial pressure were more dependent on translational acceleration while the primary determinant for the development of shear stresses in the brain is rotational acceleration. Although the current head injury criterion is based almost entirely on translational acceleration, it is recommended that any new criterion should reflect the contribution of both translational and rotational acceleration.
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Kim J, Hwang JS, Cho YK, Han Y, Jeon YJ, Yang KH. Protective effects of (-)-epigallocatechin-3-gallate on UVA- and UVB-induced skin damage. SKIN PHARMACOLOGY AND APPLIED SKIN PHYSIOLOGY 2001; 14:11-9. [PMID: 11174086 DOI: 10.1159/000056329] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been known that green tea and its components possess significant chemopreventive effects against chemical carcinogens and photo-caused skin tumor formation. In this study, the protective effects of (-)-epigallocatechin-3-gallate (EGCG), a major green tea catechin, on the ultraviolet (UV)-induced skin damage (photoaging) were studied in guinea pigs, hairless mice and human dermal fibroblast cultures. The lipid peroxidation was significantly reduced in the EGCG-treated group. The amount of lipid peroxides produced in the control and EGCG treated group were 838 +/- 144 and 286 +/- 57 nmol/mg at 18 h after UV irradiation, respectively. UVB-induced erythema was also significantly reduced in the EGCG treated group. The erythema relative index of the control and the EGCG treated group were 311 +/- 45 and 191 +/- 49 at 16 h after UV irradiation, respectively. EGCG treatment reduced UVA-induced skin damage (roughness and sagginess) and protected from the decrease of dermal collagen in hairless mouse skin. EGCG treatment blocked the UV-induced increase of collagen secretion and collagenase mRNA level in fibroblast culture. The nuclear transcription factors NF-kappaB and AP-1 binding activities were also inhibited by EGCG treatment.
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Zhang L, Yang KH, King AI. Comparison of brain responses between frontal and lateral impacts by finite element modeling. J Neurotrauma 2001; 18:21-30. [PMID: 11200247 DOI: 10.1089/089771501750055749] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study was conducted to investigate differences in brain response due to frontal and lateral impacts based on a partially validated three-dimensional finite element model with all essential anatomical features of a human head. Identical impact and boundary conditions were used for both the frontal and lateral impact simulations. Intracranial pressure and localized shear stress distributions predicted from these impacts were analyzed. The model predicted higher positive pressures accompanied by a relatively large localized skull deformation at the impact site from a lateral impact when compared to a frontal impact. Lateral impact also induced higher localized shear stress in the core regions of the brain. Preliminary results of the simulation suggest that skull deformation and internal partitions may be responsible for the directional sensitivity of the head in terms of intracranial pressure and shear stress response. In previous experimental studies using subhuman primates, it was found that a lateral impact was more injurious than a frontal impact. In this study, shear stress in the brain predicted by the model was much higher in a lateral impact in comparison with a frontal impact of the same severity. If shear deformation is considered as an injury indicator for diffuse brain injuries, a higher shear stress due to a lateral impact indicate that the head would tend to have a decreased tolerance to shear deformation in lateral impact. More research is needed to further quantify the effect of the skull deformation and dural partitions on brain injury due to impacts from a variety of directions and at different locations.
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Iwamoto M, Miki K, Mohammad M, Nayef A, Yang KH, Begeman PC, King AI. Development of a finite element model of the human shoulder. STAPP CAR CRASH JOURNAL 2000; 44:281-97. [PMID: 17458732 DOI: 10.4271/2000-01-sc19] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Previous studies have hypothesized that the shoulder may be used to absorb some impact energy and reduce chest injury due to side impacts. Before this hypothesis can be tested, a good understanding of the injury mechanisms and the kinematics of the shoulder is critical for occupant protection in side impact. However, existing crash dummies and numerical models are not designed to reproduce the kinematics and kinetics of the human shoulder. The purpose of this study was to develop a finite element model of the human shoulder in order to achieve a deeper understanding of the injury mechanisms and the kinematics of the shoulder in side impact. Basic anthropometric data of the human shoulder used to develop the skeletal and muscular portions of this model were taken from commercial data packages. The shoulder model included three bones (the humerus, scapula and clavicle) and major ligaments and muscles around the shoulder. This model was then integrated into a human thorax model developed at Wayne State University (WSU) along with pre-existing models of other body parts such as the pelvis and the lower extremities. Material properties used for the model were taken from the literature. The model was first used to simulate lateral shoulder impact study by the Association Peugeot- Renault (APR) followed by simulations of several of the 17 rigid and padded cadaveric impacts conducted on a side impact sled at WSU. Contact forces measured at the levels of shoulder, thorax, abdomen and pelvis were used as response variables to validate the model. Additionally, a cadaveric test involving the deployment of a generic side airbag was also used to check the validity of the model. Model prediction of accelerations of the shoulder matched well against those measured experimentally. The role of the shoulder in side impact protection and the reduction of injury to the ribcage are discussed, based on model results.
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146
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Yang KH, Blackwell KT. Analogue pattern matching in a dendritic spine model based on phosphorylation of potassium channels. NETWORK (BRISTOL, ENGLAND) 2000; 11:281-297. [PMID: 11128168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Modification of potassium channels by protein phosphorylation has been shown to play a role in learning and memory. If such memory storage machinery were part of dendritic spines, then a set of spines could act as an 'analogue pattern matching' device by learning a repeatedly presented pattern of synaptic activation. In this study, the plausibility of such analogue pattern matching is investigated in a detailed circuit model of a set of spines attached to a dendritic branch. Each spine head contains an AMPA synaptic channel in parallel with a calcium-dependent potassium channel whose sensitivity depends on its phosphorylation state. Repeated presentation of synaptic activity results in calcium activation of protein kinases and subsequent channel phosphorylation. Simulations demonstrate that signal strength is greatest when the synaptic input pattern is equal to the previously learned pattern, and smaller when components of the synaptic input pattern are either smaller or larger than corresponding components of the previously learned pattern. Therefore, our results indicate that dendritic spines may act as an analogue pattern matching device, and suggest that modulation of potassium channels by protein kinases may mediate neuronal pattern recognition.
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Luan F, Yang KH, Deng B, Begeman PC, Tashman S, King AI. Qualitative analysis of neck kinematics during low-speed rear-end impact. Clin Biomech (Bristol, Avon) 2000; 15:649-57. [PMID: 10946097 DOI: 10.1016/s0268-0033(00)00031-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To analyze neck kinematics and loading patterns during rear-end impacts. DESIGN The motion of each cervical vertebra was captured using a 250 frame/s X-ray system during a whole body rear-end impact. These data were analyzed in order to understand different phases of neck loading during rear-end impact. BACKGROUND The mechanism of whiplash injury remains largely unknown. An understanding of the underlying kinematics of whiplash is crucial to the identification of possible injury mechanisms before countermeasures can be designed. METHODS Metallic markers were inserted into the vertebral bodies and spinous processes of each of the seven cervical vertebrae. Relative displacement-time traces between each pair of adjacent cervical vertebrae were calculated from X-ray data. Qualitative analyses of the kinematics of the neck at different phase of impact were performed. RESULTS The neck experiences compression, tension, shear, flexion and extension at different cervical levels and/or during different stages of the whiplash event. CONCLUSIONS Neck kinematics during whiplash is rather complicated and greatly influenced by the rotation of the thoracic spine, which occurs as a result of the straightening of the kyphotic thoracic curvature. RELEVANCE Understanding the complicated kinematics of a rear-end impact may help clinicians and researchers shed some light on potential mechanisms of whiplash neck injury.
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148
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Deng B, Begeman PC, Yang KH, Tashman S, King AI. Kinematics of human cadaver cervical spine during low speed rear-end impacts. STAPP CAR CRASH JOURNAL 2000; 44:171-88. [PMID: 17458726 DOI: 10.4271/2000-01-sc13] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The purposes of this study were to measure the relative linear and angular displacements of each pair of adjacent cervical vertebrae and to compute changes in distance between two adjacent facet joint landmarks during low posterior-anterior (+Gx) acceleration without significant hyperextension of the head. A total of twentysix low speed rear-end impacts were conducted using six postmortem human specimens. Each cadaver was instrumented with two to three neck targets embedded in each cervical vertebra and nine accelerometers on the head. Sequential x-ray images were collected and analyzed. Two seatback orientations were studied. In the global coordinate system, the head, the cervical vertebrae, and the first or second thoracic vertebra (T1 or T2) were in extension during rear-end impacts. The head showed less extension in comparison with the cervical spine. Relative motion for each cervical motion segment went from flexion at the upper cervical levels to extension at the lower cervical levels, with a transition region at the mid-cervical levels. This rotational pattern formed an "S" shape in the cervical spine during the initial phase of low-speed rear impacts. A pair of facet joint landmarks on each cervical motion segment was used to measure the distance across the joint space. Uni-axial facet capsular strains were calculated by dividing changes in this distance over the original distance in seven tests using three specimens. In 20-degree seatback tests, the average strain was 32+/-11% for the C2/C3 facet joint (17%-43% range), and 59+/-26% for the C3/C4 facet joint (41%-97% range). The C4/C5 and C5/C6 facet joints exhibited peak tensile or compressive strains in different specimens. In 0-degree seatback tests, the average strain was 28+/-11% for the C2/C3 facet joint (21%-41% range), 30+/-9% for the C3/C4 facet joint (21%-39% range), 22+/-4% for the C4/C5 facet joint (19%-25% range), and 60+/-13% for the C5/C6 facet joint (51%-69% range). In 20-degree seatback tests, there was less initial cervical lordosis, more upward ramping of the thoracic spine, and more relative rotation of each cervical motion segment in comparison with the 0-degree seatback tests. Relative to T1, the head went from flexion to extension for 20-degree seatback tests while stayed in extension for 0-degree seatback tests.
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149
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Choi YJ, Lee JD, Yang KH, Woo JY, Kim BK, Bang BK, Shim SI. Immunotactoid glomerulopathy associated with idiopathic hypereosinophilic syndrome. Am J Nephrol 2000; 18:337-43. [PMID: 9653841 DOI: 10.1159/000013362] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A case of immunotactoid glomerulopathy in an 18-year-old man with an idiopathic hypereosinophilic syndrome is presented. The patient showed cervical lymphadenopathy, asymptomatic proteinuria of nephrotic range, and hematuria without any defined immunologic disease. Marked and prolonged hypereosinophilia was found in peripheral blood (eosinophil count; 6,248/mm3) and bone marrow (eosinophil series; 32%). Diffuse and/or nodular eosinophilic infiltration was identified in multiple organs such as kidney, stomach, liver, lymph node, and skin. Renal biopsy revealed endocapillary proliferative features of typical immunotactoid glomerulopathy with IgG and C3 deposition and microtubular structures of variable size, 20-80 nm in diameter, mainly in the subendothelium. This study suggests that immunotactoid glomerulopathy may be a secondary immunologic manifestation of the tissue damage by eosinophils in the idiopathic hypereosinophilic syndrome.
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150
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Tsai SJ, Hong CJ, Yu YW, Lin CH, Song HL, Lai HC, Yang KH. Association study of a functional serotonin transporter gene polymorphism with schizophrenia, psychopathology and clozapine response. Schizophr Res 2000; 44:177-81. [PMID: 10962219 DOI: 10.1016/s0920-9964(99)00170-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Serotonin is implicated in the pathogenesis of schizophrenia. Following serotonin release, the serotonin transporter (5-HTT) is the major determinant of serotonin inactivation. The present study tested the hypothesis that a biallelic polymorphism in the 5' regulatory region of the 5-HTT gene (5-HTTLPR) confers susceptibility to schizophrenia, association with the clinical manifestations of schizophrenia or clozapine response. 90 treatment-resistant schizophrenic patients were assessed using the Brief Psychiatric Rating Scale before and after clozapine treatment. The results demonstrated that the 5-HTTLPR variants did not play a major role in the susceptibility, clinical manifestations or clozapine response in schizophrenia.
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