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Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Genetic polymorphisms of cytochrome P450 1A1 and susceptibility of early-onset Parkinson's disease].

OBJECTIVE: To assess the possible association between the Msp I polymorphisms of cytochrome P450 1A1(CYP1A1) and the susceptibility of early-onset Parkinson's disease among Hans in the northern part of China. METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to analyze three genotypes A, B and C in 3'flanking region of CYP1A1 in 126 patients with idiopathic early-onset Parkinson's disease and 172 healthy controls. RESULTS: The frequencies of genotypes A, B and C in patients were 41.3%, 43.6% and 15.1% while those in the controls were 34.9%, 51.7% and 13.4%, respectively. No statistically significant difference in the frequencies of the three genotypes was observed between the two groups. The frequencies of two alleles were of no significant difference between the patients and controls. CONCLUSION: The above results suggest that the Msp I polymorphisms of cytochrome P450 1A1 itself might not be associated with idiopathic early-onset Parkinson's disease.

Adult↗
PubMed2001

Tissue factor--a receptor involved in the control of cellular properties, including angiogenesis.

Tissue factor (TF), the major initiator of blood coagulation, serves as a regulator of angiogenesis, tumor growth and metastasis. In several models, TF expression mediates upregulation of the proangiogenic vasular endothelial growth factor (VEGF) that can directly act on endothelial cells to promote vessel formation. This occurs through ligand binding, activation of signaling cascades, signal transduction and alteration of growth factor expression and is mediated by both, coagulation-dependent and -independent pathways. Depending on the cell type and the biological settings, TF seems to affect cellular properties through (i) factor VIIa (FVIIa)-dependent proteolysis of factor Xa (FXa) and thrombin and subsequent activation of proteinase activated receptor (PAR) -1 and PAR-2, (ii) through direct FVIIa signaling and mitogen activated protein (MAP) kinase activation, that is conferred by a not yet identified receptor, (iii) through interaction of FVII(a) proteolytic activity and signaling of the cytoplasmic domain and (iv) through cytoplasmic signaling independent of ligand binding. The role of phosphorylation of the cytoplasmic domain and the pathways controlling phosphorylation of TF remain poorly understood.

Animals↗
PubMed2001

[The biological effect of matrix metalloproteinase-1 in epidermal repair].

OBJECTIVE: To review the role of matrix metalloproteinase-1 (MMP-1) in the course of healing in wounded skin. METHODS: The recent literatures on MMP-1 in skin wound repair were reviewed, which gave the insight into the local effect of MMP-1 during re-epithelialization. RESULTS: Following injury, basal keratinocytes, moving from the wound edge and interact with dermal matrix proteins in the wound bed, were induced to express MMP-1 in a specific space-time pattern. MMP-1 cleaved the collagen, thereby altering its structure and affinity by which the keratinocytes binded it. MMP-1 served a beneficial role in wound healing by facilitating the proliferation and movement of keratinocytes over the collagen-rich wound bed during re-epithelialization. CONCLUSION: MMP-1 expression of migrating keratinocytes directly influences the re-epithelialization during the course of healing of the wounded skin.

Collagen↗
PubMed2001

[A preliminary result of treatment of progressive multiple sclerosis with autologous peripheral blood stem cell transplantation in China].

OBJECTIVE: To explore the clinical effect for treatment of progressive multiple sclerosis (PMS) by autologous peripheral blood stem cell transplantation (Auto-PBSCT). METHODS: One PMS patient was chosen. Peripheral blood stem cells (PBSCs) were mobilized with cyclophosphamide and G-CSF. The CD34+ cells harvesting was performed by continuous flow leukapheresis using a CS3000 plus blood separator. About 12.2 x 10(6) CD34+ cells/kg was collected and preserved at -196 degrees C in liquid nitrogen. PBSCs were reinfused after conditioned by CTX (120 mg/kg) and TBI(10 GY). G-CSF was used to help hematopoietic and immunologic reconstitution. RESULTS: After transplantation the patient received clinical remission, and the abnormal signals of MRI in T1-T4 disappeared, the examination results of the neuro-electrophysiology and T cell subgroup were improved obviously. There was no relapse after 6 months follow up. CONCLUSIONS: Auto-PBSCT is effective and safety for PMS. Duration of remission remains to be decided in long-term follow up.

Adult↗
PubMed2001

Growth inhibition of epidermal growth factor-stimulated human glioblastoma cells by nicardipine in vitro.

BACKGROUND: The objective of this work was to observe and analyze the effects of epidermal growth factor (EGF) and the calcium channel antagonist nicardipine on the growth of U251MG, a human malignant glioma cell line, which have high-affinity EGF receptors. METHODS: The growth effects of EGF and nicardipine on U251MG cultured in serum-free and serum-supplemented (10% fetal bovine serum, FBS) medium respectively were observed by MTT colorimeritric analysis. RESULTS: EGF significantly enhanced the growth of U251MG cells in a dose-dependent manner in serum-free medium. The maximal effect was seen at 20 ng/ml. The effects of EGF approximated those obtained in 10% FBS. Nicardipine decreased U251MG cell proliferation, especially in serum-supplemented medium, and completely blocked the growth-stimulated effects of EGF. The combined effects of EGF (10 ng/ml) and nicardipine equaled those of nicardipine alone. CONCLUSIONS: When serum was absent, the U251MG cells showed a pronounced mitogenic response to EGF in a dose-dependent manner, which approximated that achieved with 10% FBS. The addition of serum obscured this effect. Nicardipine suppressed the growth of U251MG cells and completely blocked the growth-stimulated effects of EGF may suggest a possible role of this drug as adjuvant therapy for human malignant gliomas.

Calcium Channel Blockers↗
PubMed2001

Simultaneous modeling of pharmacokinetics and pharmacodynamics of propafenone in healthy subjects.

AIM: To study the simultaneous modeling of pharmacokinetics and pharmacodynamics (PK-PD) of propafenone (Pro) in healthy subjects. METHODS: Ten healthy Chinese volunteers, 5 extensive metabolizers (EM) and 5 intermediate metabolizers (IM) of CYP2D6, received a single dose (400 mg) of Pro hydrochloride. The blood samples and electrocardiogram (ECG) measurements were taken after administration over 15 h period. The concentrations of Pro in plasma were measured by a reverse-phase HPLC. PR interval was used as an average value of 10 PR interval measurements. RESULTS: There was a delay between Pro level and percentage of PR interval prolongation. After PK-PD simulating, the relationship between effect concentration (Ce) and the effect met the sigmoid E(max) model. CYP2D6 (EM & IM) played an important role in both pharmacokinetics and pharmacodynamics which produced by Pro. The AUC (microg . h . L-1) of IM group was significantly higher than that of EM group (5126 +/- 1030 vs 2948 +/- 1230, P < 0.05). Whereas Ce50 (microg/L) was also greater in IM group than in EM group (747 +/- 281 vs 359 +/- 123, P < 0.05). On the other hand, gamma of EM group was about one fold larger than that of IM group (P < 0.05). CONCLUSION: CYP2D6 phenotype of human may influence not only pharmacokinetic of Pro but also its pharmacological effects.

Adult↗
PubMed2001

[Use of heterogeneous acelluar dermal matrix and autologous overthin split-thickness skin for repair of deep burn at articular sites].

OBJECTIVE: To investigate the effect of heterogeneous (swine) acellular dermal matrix (s-ADM) and autologous overthin split-thickness skin (auto-OTS) composite grafting in repair of deep burns at articular sites. METHODS: From May 1999 to April 2000, 19 articular sites in 16 patients, including 14 males and 2 females, were treated. In all the 19 sites of deep burn, the total burn area varied from 2% to 48% and the full-thickness burn area varied from 1% to 35%. After the primary escharectomy (1 to 5 days later) and complete hemostasis, the s-ADM was utilized to cover the exposed articular sites and the auto-OTS was transferred on the surface of sutured s-ADM. The size of s-ADM applied to each patient varied from 25 cm2 to 150 cm2. Regular skin grafting was adopted elsewhere other than the articular site. The survival rate of all skin grafting was evaluated and pathological examination was performed. RESULTS: The survival rate of the composite skin was (90.80 +/- 18.34)%, which was obvious higher than the survival rate of contiguous granulosum skin grafting (P < 0.05) and almost the same with that of snip skin grafting(P > 0.05). The survived composite skin appeared as smooth and soft as normal skin, and the function of articular site almost recovered with neglectable hypertrophic scar. The pathological examination revealed that the normal cell grew into s-ADM with regularly arranged collagen fiber and neovascularization in the matrix. CONCLUSION: The combination of s-ADM and auto-OTS graft is cheap and effective method to cover wound and minimize hypertrophic scar.

Adolescent↗
PubMed2001

[Association between dopamine transporter gene polymorphism and Parkinson's disease].

OBJECTIVE: To detect the association between dopamine transporter gene polymorphism and Parkinson's disease (PD). METHODS: The authors analyzed the difference in the distribution of the variable number tandem repeat (VNTR ) polymorphism within the 3' untranslated region of the DAT gene between 85 normal controls and 128 PD patients that were further divided into the senile subgroup (aged >50 years at onset of PD ) and the early-onset subgroup (aged </=50 years). RESULTS: There were significant differences in genotypic and allelic distribution between the control group and the PD group. The senile PD was strongly associated with the 7-copy allele and weakly with the 10-copy allele, and the early onset PD was mainly associated with the 9-copy allele. CONCLUSION: The findings not only support an association between DAT gene and PD but also suggest the relationship of the 3'VNTR polymorphism of DAT gene with the age at the onset of PD.

Adolescent↗
PubMed2001

[Phosphorylation of gap junction gene connexin 43 protein and dissociated calcium in HeLa cell line by all-trans-retinoic acid].

OBJECTIVE: To investigate the regulation effect on signal transduction pathway of gap junction gene connexin (Cx)43 in human cervical carcinoma cell line HeLa by all-trans-retinoic acid(ATRA). METHODS: Cell culture, Fluo-3 AM loading and laser scanning confocal microscope, flowcytometer(FCM) and western blot were employed to detect expression and regulation effect on signal transduction pathway of gap junction gene connexin Cx43 in HeLa cells by retinotic acid(RA). RESULTS: After treated with ATRA, the intercellular second messenger dissociated calcium ([Ca2+]i) was much higher in HeLa cells (58.16 mumol/L) than untreated cell (35.73 mumol/L). A detectable and up-regulation of Cx43 of 43,000 protein in HeLa cells increased from 1.9% to 26.3% in RA-treated cells than untreated cell examined by FCM and western blot. Immunoblot analysis showed that only the treated cells had phosphorylated form of Cx43 protein. CONCLUSION: The anti-tumor effect of ATRA in HeLa cells might be due to up-regulation of Cx43 gene and its signal transduction pathway which medials gap junction intercellular communication.

Calcium↗
PubMed2001

[A pilot study in treatment of systemic lupus erythematosus by autologous bone marrow transplant].

OBJECTIVE: To explore the clinical effect for treatment of SLE by autologous bone marrow transplantation(ABMT). METHODS: Three patients with refractory SLE were chosen. BM stem cells were harvested from the posterior superior iliac crests under epidural anesthesia and preserved in 4 degrees C. BM stem cells were reinfused after conditioned by CTX (120 mg/kg) and malphalan (140 mg/m(2)) or VP-16 (1.0 g/m(2)). G-CSF was used to help hematopoietic and immunologic reconstitution. RESULTS: These three patients had clinical remission after transplantation; the levels of immunoglobulins declined and complements rose up. Most of the auto-antibodies turned negative. Skin pathology in case 2 showed that the former tissue injury alleviated or disappeared. Moreover, myocardial hypertrophy and pericardial effusion also disappeared. CONCLUSIONS: (1) ABMT is obviously effective for SLE. The duration of remission remains to be decided in long-term follow up. (2) Mechanisms of improvement are possibly related to decrease of immunologic pathological cells in tissues after conditioning, reduction of the level of immunoglobulins and drop of the quantity of auto-antibodies.

Adolescent↗
PubMed2001

[A clinical analysis of 102 cases of chronic n-hexane intoxication].

OBJECTIVE: Chronic n-hexane exposure can result in n-hexane intoxication which is mainly characterized by a series of manifestations of peripheral nerve lesions. The disease was sometimes misdiagnosed as "unknown multiple peripheral neuropathy". 102 cases of n-hexane intoxication were investigated and reported in order to call attention to the disease. METHODS: All the 102 cases, male 30, female 72; age 17 - 29, mean (21 +/- 3) were n-hexane workers. During the hospitalization the following data were collected: medical history, neurological check up, electromyogram, electrocardiogram, serum biochemical analysis, ophthalmologic study and the metabolite of n-hexane- the urinary 2, 5-hexanedione level. The airborne n-hexane levels of the working environment were also measured. RESULTS: The average incubation period of the 102 cases was (8.3 +/- 2.6) months. The average course of the disease was (12.1 +/- 4.2) months. Airborne n-hexane concentration of the working places ranged from 188.0 to 7,848.6 mg/m(3). The most common prodromes were headache, anorexia, dizziness and weight loss. The main clinical manifestations of the disease were ascending abnormal sensation. Sensory loss and dyskinesia began from the distant parts of the limbs. The patient had reduction or disappearance of tendon reflexes, weakness and muscle atrophy in the limbs. Electromyography showed a neuropathic pattern, which was parallel to the clinical symptoms and signs. Delayed worsening of symptoms and signs after cessation of n-hexane exposure was observed in some cases. All the 102 cases recovered totally after treatment with Vitamin B, Chinese traditional medicine, physical therapy and training. CONCLUSION: The main lesion of the disease is multiple peripheral neuropathy. Diagnosis should be made according to the history of n-hexane exposure, the typical clinical manifestations of peripheral neuropathy as well as the neuropathic changes on electromyography. Therapeutic measures for peripheral neuropathy of other etiologies may be used and the prognosis is optimistic if correct diagnosis is made and further exposure stopped.

Adolescent↗
PubMed2001

Gene expression of inducible nitric oxide synthase in injured spinal cord tissue.

OBJECTIVE: To investigate gene expression of inducible nitric oxide synthase (iNOS) in injured spinal cord tissue of rats. METHODS: Thirty-six adult Sprague-Dawley rats were divided randomly into six groups: a normal group and five injury groups, six animals in ea ch group. Animals in the injury groups were killed at 2, 6, 12, 24, 48 hours after injury, respectively. A compression injury model of spinal cord was established according to Nystrom B et al, and gene expression of iNOS in spinal cord tissue was examined by means of reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Gene expression of iNOS was not detectable in normal spinal cord tissue but was seen in the injury groups. The expression was gradually up -regulated, reaching the maximum at 24 hours. The expression at 48 hours began to decrease but was still significantly higher than that at 2 hours. CONCLUSIONS: iNOS is not involved in the normal physiological activities of spinal cord. Expression of iNOS is up-regulated in spinal cord tissue in response to injury and the up-regulation exists mainly in the late stage after injury. Over-expression of iNOS may contribute to the l ate injury of spinal cord.

Animals↗
PubMed2001

[The experiences in correction of cicatricial foot drop in 28 patients].

OBJECTIVE: To summarize the experiences in correction of cicatricial foot drop. METHODS: 37 cicatricial drop feet in 28 postburn patients were treated in recent 4 years. The cicatricial flap survival rate was documented to compare the effects of two surgical designs, the different intervals from burn to the operation and three surgical methods used in early burn stage. RESULTS: All of the 37 wounded feet got satisfactory correction. There was no significant statistic difference in flap survival between the two surgical designs. More necrosis of the flap was observed in patients who received early escharectomy (including full thickness skin and fat) or had been burned for less than 1.5 years. CONCLUSIONS: The reverse design of the Achilles tendon flap for correction of drop foot was as safe and effective as a routine design. The operation method used in early burn stage and the interval from burn to the corrective operation should be considered in cicatricial flap design.

Achilles Tendon↗
PubMed2001

[Repair of the postburn scar of face, neck and chest with extensive tissue expanding technique].

OBJECTIVE: To explore the treatment effects of extensive tissue expanding technique on the postburn scar of face, neck and chest. METHODS: The technique was applied in 13 patients with post-burn scar of face, neck and chest. Different number of expanders (usually 5-8) with volume of 30 ml to 450 ml each were implanted under the adjacent normal skin. The principle of plastic surgery was observed during the operation with attention to locating sear lines along leavage lines and in obscure areas. The criteria for cure were correct restoration of the position of the five organs on the face, restoration of the correct angle of jaw and neck and avoidance of skin grafting on the chest. RESULTS: All the postburn scar on face, neck and chest was removed en masse with all the flaps survived with satisfactory color and texture with this technique. In addition, the appearance and the function of facial organs and neck and chest were restored perfectly. CONCLUSION: Extensive tissue expanding technique is satisfactory in the repair of postburn scars of face, neck and chest.

Adolescent↗
PubMed2001

[The inhibitory effect of CLA on mice forestomach neoplasia induced by B(a)P].

OBJECTIVE: To study the inhibitory effect of CLA on the postinitiation phase of forestomach neoplasia formation induced by B(a)P and explore its possible mechanism of anticarcinogenesis. METHODS: Kunming mice were divided into five groups, i.e. salad oil control group, CLA control group, B(a)P group, B(a)P + high dose CLA group and B(a)P + low dose CLA group. The experimental period was 23 weeks, and the endpoints included cell proliferation, expression of Pan-ras P21 and some enzymes. RESULTS: Short term CLA treated significantly inhibited the forestomach neoplasia formation induced by B(a)P at postinitiation phase. The incidence of tumor in the groups of B(a)P, B(a)P + high dose CLA and B(a)P + low dose CLA was 100%, 60% and 69% respectively (P < 0.05). The possible mechanism of this anticarcinogenic effect may be related to the inhibition of cell proliferation and the induction of the activities of GSH-Px, GST and SOD, irrespective of the regulation of expression of Pan-ras P21. CONCLUSION: CLA is a promising chemopreventive agent, and its anticarcinogenic effect may involve its effects on the redox system.

Animals↗
PubMed2001

[Clinical observation of phacoemulsification with foldable intraocular lens implantation through a limbus incision].

OBJECTIVE: To investigate the clinical therapeutic effects of phaco-emulsification with foldable intraocular lens implantation through a limbus tunnel incision. METHODS: Eighty-six patients (107 eyes) with senile cataract underwent phacoemulsification with acrylic foldable posterior chamber intraocular lens implantation through a 4 mm superior limbus tunnel incision. RESULTS: The corrected visual acuity of 0.5 or better was 62.6% at the 1st day, and 76.6%, 92.5% and 88.8% respectively at the 1st week, 1st month and 3rd month postoperatively. CONCLUSION: Phacoemulsification with foldable intraocular lens implantation through a limbus tunnel incision has advantages of both scleral tunnel incision and clear corneal tunnel incision. The postoperative therapeutic effects are satisfactory.

Adult↗
PubMed2001

[Profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis of rats induced by N, N'dinitrosopiperazine (DNP)].

OBJECTIVE: To investigate the profile of telomerase and telomerase RNA expression in nasopharyngeal carcinogenesis (NPC) induced by N, N'dinitrosopiperazine (DNP) and examined histolofically. METHODS: Nasopharyngeal carcinomas of rats were induced by DNP and examined histologically. PCR-ELISA and nested RT-PCR were used to assay telomerase and telomerase RNA expression at different stages in the nasopharyngeal tissues of rats. RESULTS: During the carcinogenesis process, telomerase activity increased along with the formation of a nasopharyngeal carcinoma. Telomerase expression was positively related with nasopharyngeal carcinogenesis. Telomerase RNA expression was present and did not change during the NPC process. Expression of telomease RNA was earlier than telomerase activation. Telomerase activation and telomerase RNA expressin were also detected in the pre-cancerous nasopharyngeal lesions. CONCLUSION: Telomerase activation may participate in the onset and progression of NPC, and is an early step in NPC.

Animals↗