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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 649 records · Page 36Linked to original sources
PubMed2001

[Prospective study of lethal blood concentration of organophosphorous in humans].

Total cases of organophosphorous (dichlorvos, methamidophos, dimethoate) poisoning outpatients from six hospitals during four years were collected consecutively for lethal blood concentration study. Blood samples were detected with gas chromatography. The probabilities of death, coma were analyzed with Bliss method and their linear regressive equations of probit were obtained respectively, their 50% lethal concentrations (LC50) and 50% coma concentrations(CC50) were calculated by the formulas above. As the death rate was influenced by therapy, its natural death probability has been discussed and estimated their natural LC50 were between the LC50 and CC50 themselves. Combined LC50 and CC50, their natural LC50 were calculated.

Adolescent↗
PubMed2001

[The expression of BDNF and NT-3 in dorsal root ganglion following peripheral and central axotomy--an immunohistochemical study].

OBJECTIVE: To explore the expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-3(NT-3) in dorsal root ganglion (DRG) following peripheral and central axotomy. METHODS: Fifteen male adult cats were divided into intact group, peripheral axotomy group and central axotomy group. The ten cats of the latter two groups were subjected to unilateral peripheral cut and central processes cut respectively. The animals were allowed to survive 4 days long; L5 DRG was taken from each animal and made into frozen sections 20 microns thick. The sections were stained using antisera of BDNF and NT-3 respectively by immunohistchemical ABC method. The neuronal numbers of BDNF and NT-3 of the three groups were counted and compared. RESULTS: The positive products of BDNF were mainly distributed in small to medium sized neurons (13-57 microns) while those of NT-3 were mainly in large sized neurons (57-100 microns). The neuronal numbers of BDNF and NT-3 in peripheral and central axotomy groups (24.1 +/- 3.5, 29.4 +/- 5.2; 19.4 +/- 2.4, 20.2 +/- 1.9) increased significantly than those of intact group (12.1 +/- 2.2, 13.3 +/- 2.9), P < 0.01. And the neuronal numbers of BDNF and NT-3 in peripheral axotomy groups were more than those of central axotomy group(P < 0.05). CONCLUSION: The results indicate that peripheral axotomy and central axotomy lead to the increase of the expression of BDNF and NT-3 in DRG neurons. And the effect of peripheral axotomy is greater than that of central axotomy.

Animals↗
PubMed2001

[Studies on insulin-like growth factor I receptor in fetal rats with intrauterine growth retardation].

OBJECTIVE: This study was conducted to detect the localization of the insulin-like growth factor I receptor (IGF-I R) in the cells and tissues in the rats with intrauterine growth retardation (IUGR) and normal growth rats. METHODS: 21 pregnant rats were randomly divided into the experimental group (IUGR) (n = 12) and the control group (n = 9). Animal models for IUGR were established by clamping the uterine vasculature of pregnant rats for 20 minutes on day 14 of gestation. The control group rats were subjected to Sham-operation. On day 22 of gestation, fetal rats were delivered by cesarean section. Immunohistochemical assay was performed to detect the IGF-I R expression on liver and lung using specific polyclonal antibodies to rat IGF-I R. RESULTS: In the experimental group, the IUGR rats' body weight, height, and the weight of their liver, lung and the placenta were significantly lower than those in the control group. In the IUGR rats' liver, the area ratio of IGF-I R was increased and the average gray level was decreased, compared with those in the control group. In the IUGR rats' lung, the area ratio of IGF-I R was increased, compared with that in the control group, but no difference of average gray level was observed between the two groups. CONCLUSION: The increased expression of IGF-I R in rats with IUGR, may be due to the decrease of IGF-I and the compensative mechanism of the body.

Animals↗
PubMed2001

[Nutritional status assessment of patients with oral maxillofacial cancers].

OBJECTIVE: The objective of the study is to evaluate the nutritional status of patients with oral maxillofacial cancer. METHODS: The nutritional status was evaluated using seven easily determined variables and multi-factor nutritional index in 50 hospitalized patients with oral maxillofacial cancer from 1990 to 1992. RESULTS: Fifty-six percent of patients had protein-energy malnutrition. The high incidence of protein-energy malnutrition was found in those patients without adequate dietary intake. CONCLUSION: Patients with oral maxillofacial cancer usually have protein-energy malnutrition. The reason is that the patients always have an inadequate dietary intake.

Adolescent↗
PubMed2001

[Changes of osteocalcin in serum of young SD rats after functional protrusion].

OBJECTIVE: The aim of this study is to investigate temporal and spatial change patterns of osteocalcin in serum of young growing SD rats, in conditions of different functional treatment time spans. METHODS: Totally, 72 SD rats are randomly divided into 3 groups, including the control group, the 24-hour wearing group (wearing functional appliance 24 hours a day), and the 12-hour wearing group (wearing appliance for 12 hours in daylight). One week after the experiment, rats were sacrificed and osteocalcin level in serum was measured by using radioimmunoassay. Date was processed using macroscopic and microscopic analysis. RESULTS: Serum osteocalcin had circadian rhythm and the peak was about 12:00 in a day. After wearing the functional appliance, serum osteocalcin level increased with treatment time, and serum osteocalcin level in the 24-hour wearing group rose more obviously than that in the 12-hour wearing group. CONCLUSION: For the functional appliance, better results can be achieved in the 24-hour wearing group.

Animals↗
PubMed2001

[A preliminary study on relationship between concentrations of human growth hormone in urine (HGH-U) and puberty].

OBJECTIVE: The aim of this study is to investigate relationship between the concentration of human growth hormone in urine (HGH-U) and puberty, and to find a simple, accurate, and acceptable way of judging puberty of patients. METHODS: The concentration of HGH-U was measured by using radioimmunoassay in 277 students of Chengdu, and students were divided into three different groups, according to their ages (9, 13, 17 years old). Half of them are male. In order to evaluate the relationship between the concentration of HGH-U and puberty, the information of age, height, weight, growth velocity and sex character of all individuals were obtained, and analyzed their relation with the concentration of individuals' HGH-U. RESULTS: 1. There was no significant difference in the concentration of HGH-U between the 9-year-old group and the 13-year-old group, but there is significant difference between the concentration of HGH-U in the 9-year-old, 13-year-old groups and that of the 17-year-old group, and the concentration in the latter group is lower than those of the former two groups. 2. The concentration of HGH-U was negatively correlated with height, body weight, age, sex character and growth velocity (P < 0.05), but the correlation coefficient is low. 3. The coefficients of variation of HGH-U in all group were higher than 30%, which indicated a low dispersion degree. CONCLUSION: The concentration of HGH-U cannot be used as an independent indicator to evaluate puberty of children.

Adolescent↗
PubMed2001

[Mitochondrial mechanisms of CPT-induced apoptosis in nasopharyngeal carcinoma cells].

OBJECTIVE: To understand whether CPT-induced apoptosis is related to the alteration of mitochondrial transmembrane potentials (delta psi m). METHOD: A low differentiation human nasopharyngeal carcinoma (NPC) cell line of CNE-2Z cells were used as in vitro model. After treatment with 2 mumol/L CPT for 24 h, the delta psi m was detected by the staining of rhodamine 123 (Rh123), while apoptosis was confirmed by sub-G1 cell content and the double staining of hoechst33258 and propidium iodide (PI). RESULT: CPT induced delta psi m collapse and apoptosis. With 2 mumol/L CPT treatment for 24 h, delta psi mlow cell was increased to (19.0 +/- 3.0)%, while in the DMSO control, delta psi mlow was (7.0 +/- 1.4)% P < 0.05. CONCLUSION: The disruption of the delta psi m may be one of the mechanisms of CPT-induced apoptosis in CNE-2Z cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

[The effects of BDP on the inflammatory cells in nasal secretions of the patients with allergic rhinitis].

OBJECTIVE: To study the effects of beclomethasone dipropionate (BDP) on the inflammatory cells in nasal secretions of the patients with allergic rhinitis. METHOD: The variation of intercellular RNA and RNA/DNA ratio of the eosinophils, neutrocyte and lymphocyte in the nasal secretions were observed under the laser scanning confocal microscopy and technology of fluorescence. RESULT: The scanning images displayed that either in eosinophils or in neutrocyte, the fluorescence signal of intercellular RNA was significantly decreased after BDP treatment, and the intercellular RNA/DNA ratio was significantly reduced (eosinophils group P < 0.001, and neutrocyte group P < 0.01). The fluorescence singal of lymphocyte intercellular RNA and RNA/DNA ratio were not significantly changed (P > 0.05). CONCLUSION: BDP can reduce the content of intercellular RNA of the eosinophils and neutrocyte. The anti-inflammation function of BDP is realized by regulating the intercellular RNA synthesize and/or RNA degradation, and by inhibiting the intercellular inflammatory medium production. BDP does not directly influence the intercellular RNA metabolize of the lymphocyte.

Adult↗
PubMed2001

[Transcriptional activator PlcR regulate the expression of multiple genes in Bacillus cereus].

Food-poisoning and some diseases of human can be caused by potential pathogenic factors including phospholipases of c-type, hemolysins, enterotoxins, emetic toxin and others from Bacillus cereus which is an opportunistic pathegon. Generally, the expression of pathogenic genes is completed by a co-regulation in many bacteria. The isolation of a mutant, displaying significant reducing expression of lecithinase and general proteolytic activities, from a transposon-induced bank of B. cereus type strain ATCC14579T were described. Sequencing data revealed that a gene with high homology to transcriptional activator (plcR) of B. thuringiensis was inactivated by insertion in this mutant. The results suggest that plcR regulates the expression of multiple genes in B. cereus.

Amino Acid Sequence↗
PubMed2001

[Inhibitory effects of beta-carotene on hepatic cancer cell line SMMC-7721].

The inhibitory effect of beta-carotene on the proliferation of hepatic cancer was studied. Cells from a hepatic cancer cell line SMMC-7721 were incubated in culture media with 20, 40 and 80 mumol/L beta-carotene for 12, 24 and 48 h respectively. MTT test, Trypan blue exclusion test and DNA gel electrophoresis were used. The results of MTT test revealed that beta-carotene (20-80 mumol/L) could inhibit the proliferation of SMMC-7721 cells in a dose-dependent manner. DNA gel electrophoresis showed that the apoptosis of hepatic cancer cells could be induced by beta-carotene (40 mumol/L). It is concluded that the proliferation of hepatic cancer cells inhibited by beta-carotene, probably through interfering DNA metabolism and inducing cell apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed2001

[Feature analysis for the envelope of liver's M-mode ultrasound images].

The liver moves in response to impulses arising from the main blood vessels. The hardness of the liver may be reflected by this kind of movement. The M-mode ultrasound technique is used in this paper to detect the information of livers' motion. The motion envelope of the liver excited by the abdominal aorta is extracted using the correlation technique. Several feature parameters, such as the amplitude, the standard deviation and Fourier harmonics, are extracted from this envelope. The values of parameters were calculated from 19 normal livers and 11 patients' livers, from which the criterion was obtained to decide whether the liver was normal.

Adolescent↗
PubMed2001

[The significance of nuclear factor kappa Bp65 (NF kappa Bp65) expression on the vascular endothelial cells of rectum adenocarcinoma of human].

OBJECTIVE: This study inquired into the mechanism of cancer vascular metastasis. METHODS: The immunohistochemical method was adopted in determining the expression of intercellular adhesion molecule-1 (ICAM-1) and nuclear factor kappa B (NF kappa Bp65) on the peritumoral rectum tissues and metastatic lymph nodes of 8 patients and on the rectum tissues and lymph nodes of 5 normal human subjects. Also, the method of in situ hybridization was employed in detecting the binding site of NF kappa Bp65 on vascular endothelial cells. RESULTS: It was found that the proteins of ICAM-1 and NF kappa Bp65 were expressed on the vascular endothelial cells of the rectum adenocarcinoma patients, and there was a NF kappa B binding consensus sequences on ICAM-1 promoter in the vascular endothelial cells of the rectum adenocarcinoma patients. When DIG-AKP labeled 38-bp oligonucleotide probe was used, there was no expression of ICAM-1 and NF kappa Bp65 on the vascular endothelial cells of the normal human lymph node and rectum tissues. CONCLUSION: The above data suggest that the activation of ICAM-1 promoter may critically depend on NF kappa Bp65 homodimers or heterodimers binding to a variant kappa B site on the vascular endothelial cells of human rectum adenocarcinoma. These may indicate the potential roles of NF kappa B in cancer metastasis, thus giving clues to the development of a novel anti-metastasis strategy.

Adenocarcinoma↗
PubMed2001

[A comparison between 99mTc-Q3 and 201Tl on clearance and retention properties at varying coronary flow rates in isolated rabbit heart].

OBJECTIVE: This study was intended to investigate and compare technetium-99m-N, N'-ethylenebis(acetylacetoneiminato)bis[tris (3-methoxy-1-propyl) phosphine] (99mTc-Q3) versus 201Tl on clearance and retention properties at varying coronary flow rates in isolated rabbit heart. METHODS: 20 New Zealand White rabbits were anaesthetized and excised through a median sternotomy. The hearts were isolated and arrested in ice-cold saline. The external perfusion models with isolated rabbit hearts were installed and were perfused at flow rates ranging from 0.52 to 3.75 ml/(g wet wt.min) in the absence of tracer recirculation. Furthermore, 99mTc-Q3 experimental relations between uptake, clearance and retention were explored in comparison with 201Tl. RESULTS: 201Tl net uptake was higher and also more affected by flow rates (P < 0.05) as compared with 99mTc-Q3 net uptake. 201Tl clearance was faster than 99mTc-Q3 clearance within 4 to 25 minutes after radiopharmaceuticals injection in high flow rates group, and 201Tl clearance was faster than 99mTc-Q3 clearance within 40 minutes after radiopharmaceuticals injection in low flow rates group. 201Tl earlier rapid clearance observed in the high flow rates group did not appear in the low flow rates group, but 99mTc-Q3 did not display early rapid clearance either in the high flow rates group or in the low flow rates group. CONCLUSION: Owing to faster clearance, the superiority of 201Tl over 99mTc-Q3 as a myocardial perfusion imaging agent would be lost entirely within 10 minutes after injection of agent, therefore 99mTc-Q3 is still a good myocardial perfusion imaging agent, and further study is worth doing.

Animals↗
PubMed2001

[Study on DNA oxidative damage of O3 aging model in mice].

OBJECTIVE: This study was aimed to detect the animals' DNA oxidative damage. METHODS: A free radical mouse aging model was established by putting the mouse in a device for inhaling quantities of ozone (O3). Single cell gel electrophoresis (SCGE) was used for assessing the splenolymphocytes' DNA damage. RESULTS: The appearance rate of comet and the length grade of DNA migration for the young control group (P < 0.05). No significant difference in the degree of DNA damage was observed between the O3 model group and the natural aging group(P > 0.05). CONCLUSION: The DNA damage of O3 animal model is consistent with that of natural aging animal; this animal model DNA damage of O3 animal model is consistent with that of natural aging animal; this animal model and the method of SCGE are useful for future researches on aging and antiaging medicine.

Aging↗
PubMed2001

[Effects of laser welding on ceramic fused to metal].

OBJECTIVE: This study was aimed to investigate the bonding effect of laser welding on ceramic fused to metal. METHODS: Ten laser welded CW-PA ceramo-alloy rods were fused with porcelain at fusion zone. The porcelain-metal bond strength was measured with pull-through test. SEM examination and EDAX analysis were performed. Ten non-welded CW-PA ceramo-alloy pull-rod plates were used as comparison. RESULTS: The results showed that the bond strength of laser welded sample was 41.32 +/- 6.69 MPa, approaching to 45.71 +/- 9.98 MPa of the non-welded sample (P > 0.05). The microscope displayed the interface compacted union of the two phase boundary. There was no change in the elements and their ratio at the fusion zone. CONCLUSION: These results indicate that laser welding does not affect ceramic fused to metal.

Dental Porcelain↗
PubMed2001

[Randomized controlled trial for the effect of amrinone and aprotinin on proinflammatory cytokine release in patients with prosthetic valve replacement during perioperative period].

OBJECTIVE: To explore the effect of amrinone and aprotinin on whole-body inflammatory response in the patients with prosthetic valve replacement during perioperative period. METHODS: 24 patients undergoing prosthetic valve replacement were randomized to control group (group A, n = 8), aprotinin group (group B, n = 8) and amrinone combined with aprotinin group (group C, n = 8). In the aprotinin group, 3 x 10(6) of aprotinin was added to the priming solution of the extracorporeal circulation (ECC). In the amrinone combined with aprotinin group 3 x 10(6) of aprotinin was added to the priming solution of the ECC and amrinone began with a bolus of 1 mg/kg followed by a maintenance infusion of 8 micrograms/(kg.min). The control group received an equivalent prime volume without aprotinin. Venous blood samples were drawn before the operation, at the end of ECC, 1 hour after the end of ECC, and one day after the operation respectively. Enzyme-linked immunosorbent assay techniques were used to measure each of the cytokines. RESULTS: Before ECC, there were no differences of the levels of IL-6 and IL-8 among groups (P > 0.05). After ECC, the levels of IL-6 and IL-8 increased significantly in all groups (P < 0.05). The levels on day one after the operation were still higher than those before the operation in all groups (except the level of IL-8 in group C), but no statistical significance was observed. (P > 0.05). At 1 hour after the end of ECC, the level of IL-6 in group B was lower than that in group A, and the level of IL-6 in group C was lower than that in group B, but there was no statistically significant difference (P > 0.05); At the end of ECC, the level of IL-8 in group B was lower than that in group A and the level of IL-8 in group C was lower than that in group B, but no significant difference was noted (P > 0.05). It was also observed that the level of IL-8 was lower in group C than group A or B at 1 hour after the end of ECC. CONCLUSION: Although amrinone and aprotinin have antiinflammatory activity, but pump prime only aprotinin or aprotinin combined with amrinone may fall in preventing proinflammatory cytokine release (IL-6, IL-8) completely in patients with prosthetic valve replacement during ECC perioperative period.

Adult↗
PubMed2001

[The risk of sustained amenorrhea in patients with systemic lupus erythematosus receiving intermittent pulse cyclophosphamide therapy].

OBJECTIVE: To determine the risk of sustained amenorrhea in premenopausal women with systemic lupus erythematosus (SLE) receiving intermittent pulse cyclophosphamide (CTX) therapy. METHODS: Prospectively comparing the amenorrhea rate of 51 cases receiving intermittent pulse cyclophosphamide therapy versus that of 22 cases receiving intermittent pulse methylprednisolone (MP) therapy. RESULTS: The amenorrhea rate was higher in the CTX group (19.6%) than in the MP group (P = 0.025). In the CTX group, the amenorrhea rate of patients aged over 30 was higher than that of patients aged 30 or below 30 (P = 0.0018). CONCLUSION: Pulse CTX therapy in fertile women with SLE is associated with increased rate of sustained amenorrhea, and the older the patient is, the higher risk for sustained amenorrhea the patient runs.

Adult↗