Biomedical subjects

Wei Chen

Publications and source records attributed to Wei Chen.

At least 505 records · Page 28Linked to original sources

PubMed2002

Analysis of wave behavior in lossy dielectric samples at high field.

Radiofrequency (RF) field wave behavior and associated nonuniform image intensity at high magnetic field strengths are examined experimentally and numerically. The RF field produced by a 10-cm-diameter surface coil at 300 MHz is evaluated in a 16-cm-diameter spherical phantom with variable salinity, and in the human head. Temporal progression of the RF field indicates that the standing wave and associated dielectric resonance occurring in a pure water phantom near 300 MHz is greatly dampened in the human head due to the strong decay of the electromagnetic wave. The characteristic image intensity distribution in the human head is the result of spatial phase distribution and amplitude modulation by the interference of the RF traveling waves determined by a given sample-coil configuration. The numerical calculation method is validated with experimental results. The general behavior of the RF field with respect to the average brain electrical properties in a frequency range of 42-350 MHz is also analyzed.

Electromagnetic Phenomena↗

PubMed2002

Polarization of the RF field in a human head at high field: a study with a quadrature surface coil at 7.0 T.

The RF field intensity distribution in the human brain becomes inhomogeneous due to wave behavior at high field. This is further complicated by the spatial distribution of RF field polarization that must be considered to predict image intensity distribution. An additional layer of complexity is involved when a quadrature coil is used for transmission and reception. To study such complicated RF field behavior, a computer modeling method was employed to investigate the RF field of a quadrature surface coil at 300 MHz. Theoretical and experimental results for a phantom and the human head at 7.0 T are presented. The results are theoretically important and practically useful for high-field quadrature coil design and application.

Brain↗

PubMed2002

Forceps-guided nuclear cleavage cataract extraction.

We introduce a manual nuclear fragmentation technique, forceps-guided nuclear cleavage. A 5.5 to 7.0 mm superior scleral incision is started 1.5 mm posterior to the limbus. Two additional 1.0 mm paracenteses are made at 3 and 9 o'clock in clear cornea close to the limbus. A continuous curvilinear capsulorhexis (CCC) is created; in most cases, 4 to 5 radial relaxing incisions are made in the CCC. The anterior and equatorial cortex and epinucleus are removed with 2-handed irrigation/aspiration via the 2 paracenteses with the nucleus in the capsular bag. The nucleus is prolapsed into the anterior chamber. A nucleus hook is inserted via the 3 o'clock paracentesis and applied to the 6 o'clock nuclear equator to hold the nucleus. A nucleus cleaving forceps is inserted through the upper incision to the 12 o'clock equator of the nucleus and advanced to one-third depth of the nucleus. The forceps is relaxed while the nucleus is cleaved in half.

Aged↗

PubMed2002

Childhood blood pressure predicts adult microalbuminuria in African Americans, but not in whites: the Bogalusa Heart Study.

BACKGROUND: Microalbuminuria is considered as a strong predictor of cardiovascular diseases. However, limited information is available for childhood blood pressure (BP) levels and microalbuminuria in adulthood. METHODS: This study examined 2,122 individuals enrolled in the Bogalusa Heart Study as children, aged 5 to 17 years, and as adults, aged 20 to 37 years, with an average follow-up period of 16 years. Microalbuminuria is defined as urinary albumin (in milligrams per liter) to creatinine (mmoles per liter) ratio at or above the 90th percentile specific for age, ethnicity, and sex or urinary albumin levels >/=30 mg/L. RESULTS: As children, African American boys had higher BP than white boys. As adults, African Americans had higher BP and urinary albumin/creatinine ratio than whites. After adjusting for age, sex, and body mass index (BMI), African Americans with microalbuminuria in adulthood by either measure had higher systolic (P =.03) and diastolic (P =.02) BP as adults, and higher diastolic (P <.01) as children than those without this condition. On the other hand, whites showed no such significant association. In a multivariate regression analysis, adjusting for sex, childhood BMI, and age, and current smoking status, childhood BP and rate of change in BP from childhood to adulthood were significant predictors of increased urine albumin excretion in African Americans, but not in whites. CONCLUSIONS: Elevated BP beginning in childhood is associated with microalbuminuria in adulthood in African Americans, but not in whites, suggesting that African Americans may be more susceptible than whites to BP-related renal damage.

Adolescent↗

PubMed2002

Added clinical benefit of incorporating 2-deoxy-2-[18F]fluoro-D-glucose with positron emission tomography into the clinical evaluation of patients with cognitive impairment.

PURPOSE: Growing evidence indicates that appropriate incorporation of positron emission tomography (PET) into the evaluation of patients with early symptoms of cognitive decline can improve diagnostic and prognostic accuracy. In the present work, an explicitly defined role for PET and its associated impact on expected clinical outcomes were systematically examined. PROCEDURES: We compared the relative value of two strategies for assessing whether Alzheimer's disease (AD) was responsible for cognitive decline in geriatric patients, and in subsequently managing those patients according to the recommended standards of the American Academy of Neurology (AAN). The first strategy was based on an approach already endorsed by the AAN, following evidence-based reviews carried out by its quality standards subcommittee. The second approach was based on many of the same AAN recommendations-with respect to initial general medical and neurologic examination, structural imaging and laboratory tests, as well as ultimate management-but additionally incorporated PET in appropriate cases, to determine the presence or absence of a pattern of regional cerebral metabolism characteristic of AD. Clinical outcomes accruing to each strategy were calculated using formalized tools of decision analysis. RESULTS: The strategy making use of PET increased diagnostic accuracy, yielding decreased rates of both false negative (from 8.3 to 3.1%) and false positive (from 23.0 to 11.9%) diagnoses for AD, compared with the conventional strategy. When coupled with AAN treatment recommendations for patients having (or not having) non-severe AD, these differences in diagnostic accuracy corresponded to approximately a 62% decrease in avoidable months of nursing home care, and a 48% decrease in months of unnecessary drug therapy resulting from inaccurate diagnoses. The benefit in clinical outcome of the proposed strategy was maintained over a wide range of values for sensitivity, specificity, and projected impact on need for nursing home care. CONCLUSION: Use of PET for evaluating early cognitive decline in geriatric patients can add valuable information to the clinical assessment, resulting in a greater number of patients being accurately diagnosed and properly treated. PET can be used to diminish disease-related and treatment-related morbidity of dementia, through earlier institution of appropriate management.

Journal Article↗

PubMed2002

Influence of the beta2-adrenergic receptor Arg16Gly polymorphism on longitudinal changes in obesity from childhood through young adulthood in a biracial cohort: the Bogalusa Heart Study.

BACKGROUND: The beta2-adrenergic receptor (ADRB2) plays a major role in regulating energy expenditure by stimulating lipid metabolism in human adipose tissue. Polymorphisms in the ADRB2 gene have been associated with obesity and various weight-related traits in cross-sectional studies of adults, but little is known about the effects of the ADRB2 gene on childhood obesity or the propensity to gain weight over time. OBJECTIVE: To assess the effects of a polymorphism in codon 16 (Arg16-->Gly) of the ADRB2 gene, which has been associated with a decrease in beta2-receptor density and efficiency, on longitudinal changes in obesity from childhood to young adulthood in a biracial cohort. DESIGN: Seven cross-sectional screenings of children and five cross-sectional screenings of young adults who were previously examined as children produced longitudinal data from childhood to young adulthood. METHODS: Height, weight and subscapular and triceps skinfolds were measured by trained examiners following identical protocols over the course of the study. Gender- and age-stratified analyses using random coefficients models were used to examine longitudinal genetic effects on obesity in 1151 African-American and Caucasian males and females who attended an average of six examinations over a 24 y period from childhood to young adulthood. RESULTS: Age-stratified analyses showed no clear genetic relationships with changes in obesity measures over time in females, but an age-dependent association was observed in males, where the relationship between the Arg16Gly polymorphism and obesity became stronger with age. In males who were 4-9 y of age at the beginning of the study in 1973, body mass index (BMI) was 4% higher in Gly/Gly and Arg/Gly males compared to those with Arg/Arg by 26 y of age. Subscapular skinfold measurements in Gly/Gly males became significantly different from Arg/Arg males (20% higher) by age 20. In the oldest male cohort (10-14 y of age in 1973), BMI increased at a significantly greater rate (0.4%/y) in males carrying the Gly16 form of the receptor relative to Arg/Arg males. BMI was significantly different between homozygous genotypes by approximately 26 y of age, and reached 8% higher in Gly/Gly males by age 32. Subscapular skinfolds also increased at a significantly greater rate (2%/y) in Gly/Gly males compared to Arg/Arg males, becoming significantly different (27%) by approximately 22 y of age and reaching a maximum difference of 50% by age 32. CONCLUSIONS: Our data suggest that the beta2-adrenergic receptor is associated with the propensity to gain weight from childhood to young adulthood in males. An increased understanding of genetic influences on the development of obesity may improve the effectiveness of interventions designed to reduce excess body weight and help define the role of genetic factors in diabetes and cardiovascular disease.

Alleles↗

PubMed2002

Rapid determination of underivatized pyroglutamic acid, glutamic acid, glutamine and other relevant amino acids in fermentation media by LC-MS-MS.

Determination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation. The separation of seven underivatized amino acids was achieved on a reversed-phase C18 column with pentadecafluorooctanoic acid as a volatile ion-pair reagent, and the specific detection of most amino acids was achieved by MS-MS of the specific transitions [M + H]+-->[M + H - 46]+. The calibration curves of all analytes were linear over the range of 1.0-1000 microg ml(-1) and the detection limits ranged from 0.1 to 5 ng ml(-1), with an injection volume of 20 microl. The inter-day and intra-day precisions ranged from 2.6 to 5.7% and 4.8 to 8.2%, respectively; the mean recoveries of the seven analytes were 81-104%, 91-107% and 93-101% respectively at the spiked level of 10, 40 and 200 microg ml(-1). A large number of fermentation samples were analysed using this method. The technique is simple, rapid, selective and sensitive, and shows potential for the high-throughput quantitation of amino acids from other biological matrices.

Amino Acids↗

PubMed2002

Anesthesiologist board certification and patient outcomes.

BACKGROUND: Board certification is often used as a surrogate indicator of provider competence, although few outcome studies have demonstrated its validity. The aim of this study was to compare the outcomes of patients who underwent surgical procedures under the care of an anesthesiologist with or without board certification. METHODS: Medicare claims records for 144,883 patients in Pennsylvania who underwent general surgical or orthopedic procedures between 1991 and 1994 were used to determine provider-specific outcome rates adjusted to account for patient severity and case mix, and hospital characteristics. Outcomes of 8,894 cases involving midcareer anesthesiologists, 11-25 yr from medical school graduation, who lacked board certification were compared with all other cases. Midcareer anesthesiologist cases were studied because this group had sufficient time to become certified during an era when obtaining certification was already considered important, and consequently had the highest rate of board certification. Mortality within 30 days of admission and the failure-to-rescue rate (defined as the rate of death after an in-hospital complication) were the two primary outcome measures. RESULTS: Adjusted odds ratios for death and failure to rescue were greater when care was delivered by noncertified midcareer anesthesiologists (death = 1.13 [95% confidence interval, 1.00, 1.26], P < 0.04; failure to rescue = 1.13 [95% confidence interval, 1.01, 1.27], P < 0.04). Adjusting for international medical school graduates did not change these results. CONCLUSIONS: When anesthesiology board certification is very common, as in midcareer practitioners, the lack of board certification is associated with worse outcomes. However, the poor outcomes associated with noncertified providers may be a result of the hospitals at which they practice and not necessarily their manner of practice.

Adult↗

PubMed2002

Development of a human neuronal cell model for human immunodeficiency virus (HIV)-infected macrophage-induced neurotoxicity: apoptosis induced by HIV type 1 primary isolates and evidence for involvement of the Bcl-2/Bcl-xL-sensitive intrinsic apoptosis pathway.

Neuronal apoptosis within the central nervous system (CNS) is a characteristic feature of AIDS dementia, and it represents a common mechanism of neuronal death induced by neurotoxins (e.g., glutamate) released from human immunodeficiency virus (HIV)-infected macrophages (HIV/macrophage-induced neurotoxicity). Neuronal apoptosis may result from activation of the intrinsic (mitochondrial/bcl-2 regulated) or extrinsic (death receptor) pathways, although which pathway predominates in CNS HIV infection is unknown. Apoptosis initiated by the intrinsic pathway is typically blocked by antiapoptosis Bcl-2 family proteins, such as Bcl-2 and Bcl-xL, but whether these can block HIV/macrophage-induced neuronal apoptosis is unknown. To determine the potential role of the Bcl-2 family in HIV/macrophage-induced neuronal apoptosis, we developed a unique in vitro model, utilizing the NT2 neuronal cell line, primary astrocytes and macrophages, and primary CNS HIV type 1 (HIV-1) isolates. We validated our model by demonstrating that NT2.N neurons are protected against HIV-infected macrophages by N-methyl-D-aspartate (NMDA) glutamate receptor antagonists, similar to effects seen in primary neurons. We then established stable NT2.N neuronal lines that overexpress Bcl-2 or Bcl-xL (NT2.N/bcl-2 and NT2.N/bcl-xL, respectively) and determined their sensitivity to macrophages infected with primary R5, X4, and R5/X4 HIV-1 isolates. We found that NT2.N/bcl-2 and NT2.N/bcl-xL neurons were resistant to apoptosis induced by either R5, X4, or R5/X4 isolates and that resistance was abrogated by a Bcl-2 antagonist. Thus, the NMDA receptor/bcl-2-regulated apoptotic pathway contributes significantly to HIV/macrophage-induced neuronal apoptosis, and Bcl-2 family proteins protect neurons against the spectrum of primary HIV-1 isolates. Modulation of bcl-2 gene expression may therefore offer adjunctive neuroprotection against development of AIDS dementia.

AIDS Dementia Complex↗

PubMed2002

Voltage tunable electroluminescence of CdTe nanoparticle light-emitting diodes.

Strong electroluminescence was observed in a CdTe nanoparticle light-emitting diode that was fabricated by layer-by-layer assembly of poly(p-phenylenevinylene) and CdTe nanoparticles. The turn-on voltage for the electroluminescence is 4.0 V. The electroluminescence is exclusively from CdTe nanoparticles, with a 30 nm red shift in emission wavelength from the photoluminescence and shifts to longer wavelengths at higher applied voltages. Possible mechanisms for this red shift are discussed, and it is concluded that the de-trapping of surface states and trap centers due to electric excitation, the involvement of traps in the electroluminescence, and the quantum confined Stark effect are the major reasons for the red shift.

Cadmium Compounds↗

PubMed2002

Epidemiological survey on the relationship between different iodine intakes and the prevalence of hyperthyroidism.

OBJECTIVE: To investigate the effect of different levels of iodine intake on the prevalence of hyperthyroidism and the impact of universal salt iodization on the incidence of hyperthyroidism. DESIGN: A comparative cross-sectional and longitudinal survey was conducted in three areas with borderline iodine deficiency, mild iodine excess (previously mild iodine deficiency) and severe iodine excess. Universal salt iodization had been introduced 3 years previously except in the area with borderline iodine deficiency. METHODS: In total 16 287 inhabitants from three areas answered a questionnaire concerning the history of thyroid disease. Among them 3761 unselected subjects received further investigations including thyroid function, thyroid autoantibodies, thyroid ultrasonography and urinary iodine excretion. RESULTS: Among areas with median urinary iodine excretion of 103 microg/l, 375 microg/l and 615 microg/l (P<0.05), the prevalence of hyperthyroidism did not differ significantly (1.6%, 2% and 1.2%). The prevalence of subclinical hyperthyroidism was higher in areas with borderline iodine deficiency and mild iodine excess than in the area with severe excess iodine intake (3.7%, 3.9% and 1.1%, P<0.001). The prevalence of Graves' disease and its proportion in hyperthyroidism did not differ among areas. The incidence of hyperthyroidism did not significantly increase after the introduction of universal salt iodization. CONCLUSION: Different iodine intakes under a certain range do not affect the prevalence and type of hyperthyroidism. Subclinical hyperthyroidism is more prevalent in the iodine deficient area than in the severe iodine excessive area. In the area with mild iodine deficiency, the introduction of universal salt iodization may not be accompanied by an increased incidence of hyperthyroidism.

Adolescent↗

PubMed2002

PELA microspheres loaded H. pylori lysates and their mucosal immune response.

AIM: To prepare poly (D,L-lactide)-polyethylene glycol copolymer (PELA) microspheres loaded H.pylori lysates or Cystografin and observe their targeting in gastrointestinal mucous membrane or analyze the mucosal immune responses by oral administration. METHODS: PELA microspheres loaded H.pylori lysates or Cystografin were prepared by double emulsion evaporation method. Their distribution in gastrointestinal mucous membrane was observed by CT. Balb/c mice orally immunized in mucosal immune responses, whose antibody production in salivary and gut washing and antibody secreting cells in Peyer's patches (PP) were estimated by ELISA and ELISPOT, respectively. The microspheres physical properties, such as particle size, protein level and morphology were investigated. RESULTS: All prepared microspheres were found to have a smooth surface morphology from 3.20-4.05 microm in diameter and high encapsulation efficiency from 74.9-82.2 %. No significant correlation in their physical properties was shown, depending on their molecular weight at the similar composition ratio. Immunization with all types of PELA-Hp microspheres elevated the saliva sIgA level at week 3 by approximately 3-4 times that with soluble antigen, which was greatly enhanced after boosting. At one week after last immunization with all types of PELA-Hp microspheres (week 8), the specific sIgA-ASCs, IgG-ASCs and sIgA in salivary rose obviously. In intestinal Peyer's patches, the specific sIgA-ASCs were 5.92-6.98X10(4)/ml cell and IgG-ASCs were 3.47-4.02X10(4)/ml cell, about 5-9 times higher than those with soluble antigen (P<0.01). ASCs in intestine were more than those in stomach and the majority of the ASCs were sIgA-ASCs. The sIgA in gut washing fluid was 1.62-1.85 OD, about 3-6 times tthat of those with soluble antigen. There were significant differences of the ASCs and sIgA in gut washing fluid as compared with those of PBS and MS-0 (P<0.05). There appeared to be good correlation between sIgA level in gut washing fluid and sIgA-ASCs in intestinal Peyer's patches. CONCLUSION: PELA microspheres may be used as vehicle to delivery antigen and adjuvant in designing oral vaccination.

Administration, Oral↗

PubMed2002

[Construction of bi-cistronic co-expression plasmid of mIL-12 and the expression in vitro or in vivo]

OBJECTIVE: To construct a bi-cistronic co-expression plasmid for mouse interleukin-12 and to observe its expression in vitro or in vivo.METHODS: The full-length cDNA encoding p35 and p40 was cloned into eukaryotic cells expression vector pcDNA 3.1 respectively. Subsequently,the p35 expression unit was inserted into pcDNA 3.1/p40 to produce the bi-cistronic co-expression plasmid in which the p35 and p40 genes were controlled by their own CMV.The plasmid was expressed in vitro and in vivo. RESULTS: The mIL-12 in the supernatant was detected by ELISA after the pCmIL-12 was transfected into COS-7 cells. The activity of NK cells could be augmented by the supernatant in vitro and also by by intradermal delivery of pCmIL-12 in vivo. CONCLUSION: The plasmid constructed by us can express biologically active mIL-12 in vitro and in vivo.

Journal Article↗

PubMed2002

[Epidermal growth factor stimulates tissue repair in skin through skin stem cell activation].

OBJECTIVE: To explore the possible mechanisms of skin regeneration through the epidermal stem cells stimulated by epidermal growth factor (EGF). METHODS: At 8 and 14 days after treatment with EGF, the tissue specimens from 8 skin ulcered patients who were treated with EGF were used to evaluate the distribution and differentiation of epidermal stem cells. The expression of beta 1 integrin, keratin 19 (K19), keratin 14(K14) and keratin 10 (K10) in skin was detected with SP immunohistochemical methods. Hematoxylin and eosin staining method were used to observe the tissue structure. Another 7 biopsies from ulcered patients without EGF management were used as the control. RESULTS: The results from the hematoxylin and eosin staining showed that the epidermis in EGF treated wounds was thick and the epidermal ridges were enlarged both in 8 and 14 days compared with those in control skin. Immunohistochemical staining from beta 1 integrin and K 19 showed that all tissues treated with EGF were rich in epidermal stem cells both in 8 and 14 days. These stem cells were bigger in size and larger in number and localized at the base of the epidermis. In contrast, the positive expression cells of beta 1 integrin and K 19 in control group in the same time were scanty. It was found that there were some stem cell islands in epidermis treated with EGF in day 14 and absent from the control group. The expression of K14 and K10 could be observed in those terminally differentiating epidermal cells in both groups. CONCLUSION: The results indicate that the possible mechanisms of skin regeneration stimulated by EGF comes from the mitogenic effects and differentiation of skin stem cells.

Cell Differentiation↗

PubMed2002

Review of current progress in the structure and function of Smad proteins.

PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of Chinese-Language Literature (1997 - 2000). STUDY SELECTION: Data from published articles about TGF-beta signal transduction in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 22 articles which are listed in the reference section of this review. RESULTS: Smad proteins mediate signal transduction induced by the TGF-beta superfamily. Based on their structural and functional properties, Smad proteins are divided into three groups. The first group, receptor-regulated Smads (R-Smads), are phosphorylated by activated type I receptors and form heteromeric complexes with the second group of Smads, common mediator Smads (Co-Smads). These Smad complexes translocate into the nucleus to influence gene transcription. Inhibitory Smads (I-Smads) are the third group and these antagonize the activity of R-Smads. In the nucleus, Smads can directly contact Smad-binding elements (SBE) in target gene promoters. Through interaction with different transcription factors, transcriptional co-activators or co-repressors, Smads elicit different effects in various cell types. The aberrance of Smad proteins has been noted in several human disorders such as fibrosis, hypertrophic scarring and cancer. CONCLUSION: The structure of Smads determines their function as transcriptional factors which translocate signals from the cell surface to the nucleus where Smads regulate TGF-beta superfamily-dependent gene expression.

DNA-Binding Proteins↗

PubMed2002

[Study on expression of cell cycle-related genes in subclonal cell lines of human cervical carcinoma].

OBJECTIVE: To explore the role of expression of cell cycle-related genes in cervical carcinoma cell lines. METHODS: A series of expression microarray analysis of two homologous cervical carcinoma subclonal cell lines were initiated by cDNA microarray which represent a set of 234 human cell cycle-related genes. RESULTS: In normal medium, the percent of G(1) phase in CS03 cells was higher than in CS07 cells dramatically, but the percent of S phase in CS07 cells was more than in CS03 cells. After cultured 48 h in serum-free medium, the percent of apoptosis cells (sub-G(1) phase) in CS03 cells was higher than in CS07 cells significantly and increased with time. By applying this cDNA microarray, we identified 3 differentially expressed genes in two homologous cell lines, which were BN51, hsp90 and Mcl-1 genes, further identified 3 upregulated genes in CS07 cell line, the ratio of Cy5/Cy3 was 0.480, 0.479 and 0.490 respectively. CONCLUSION: Differential expression of BN51, hsp90 and Mcl-1 genes is associated to various growth patterns of human cervical carcinoma cells.

Apoptosis↗

PubMed2002

[A 1:2 matched case-control study on congenital external malformation during perinatal period].

OBJECTIVE: To investigate the risk factors for congenital external malformation. METHODS: A 1:2 matched case-control study was conducted with 52 cases of congenital external malformation during perinantal period collected from surveillance in Baoan District of Shenzhen City from January to June in 2000. RESULTS: Simple and multiple conditional logistic regression analysis showed that the major risk factors for congenital external malformations during perinatal period were preterm labor (beta(k) = 1.4171, s(theta, beta(kappa)) = 0.4601, OR = 4.115), adverse mental stimulus (beta(kappa) = 2.1870, s(theta beta(kappa)) = 0.7873, OR = 8.909), taking medicine (beta(k) = 1.9178, s(theta beta(kappa)) = 0.8072, OR = 6.808) and exposure to hazardous chemicals during early pregnancy (beta(k) = 0.9602, s(theta beta(kappa)) = 0.4262, OR = 2.612). CONCLUSIONS: Congenital external malformation during perinatal period was caused by multiple risk factors and results of the study showed that environmental and mental factors were in obvious connection with its occurrence.

Case-Control Studies↗

PubMed2002

[Change of gene expression of transforming growth factor-beta1, Smad 2 and Smad 3 in hypertrophic scars skins].

OBJECTIVE: To explore the regulatory mechanisms of transforming growth factor-beta1 (TGF-beta1) and two transcriptional factors Smad 2, 3 on hypertrophic scar formation and fetal scarless healing. METHODS: Thirty-two cases were detected to compare the gene expression of TGF-beta1, Smad 2 and Smad 3 with RT-PCR. Among those cases, there were 8 cases of hypertrophic scars, 8 cases of control skins, 8 cases of fetal skins and 8 cases of adult skins. RESULTS: TGF-beta1, Smad 2 and Smad 3 gene expression could all be detected in hypertrophic scars, fetal and adult skins. Among 8 groups examinated in this experiment (each group comprised a hypertrophic scar and its corresponding normal skin), there were 5, 8 and 5 groups in which TGF-beta1, Smad 2 and Smad 3 gene expression were higher in hypertrophic scars than in normal skins respectively. The fetal skins showed significantly lower level of TGF-beta1 and Smad 3 gene expression compared with adult skins (t = 2.204, P < 0.05 and t = 4.269, P < 0.01 respectively), while mRNA contents of Smad 2 were obviously higher in fetal skins than in adult skins (t = 6.685, P < 0.01). CONCLUSION: TGF-beta1 and its downstream signal molecules Smad 2, Smad 3 might be involved in hypertrophic scar formation. Higher gene expression of TGF-beta1, Smad 2 and Smad 3 in hypertrophic scars might lead to stimulating extracellular matrix deposition, inducing fibroblast proliferation and accelerating fibrogenesis. Lower mRNA contents of TGF-beta1 and Smad 3 in fetal skins compared with adult skins might be associated with fetal scarless healing.

Cicatrix, Hypertrophic↗