Biomedical subjects

J Chen

Publications and source records attributed to J Chen.

At least 649 records · Page 36Linked to original sources

PubMed2001

[The adhesion and seeding of NIH3T3 fibroblast on PHB surfaces].

Biodegradable polymers have been widely used in the field of tissue engineering. The adhesive characteristic of polymer surfaces is critical for cell seeding and growth. The adhesion and growth of NIH3T3 fibroblast on poly-beta-hydroxybutrpic acid (PHB) was studied here, and the cell-surface adhesion strength was measured in a shear flow detachment assay. It showed that the critical shear stress for cell detachment was relatively low on PHB, thus cells tend to aggregate and detach from surfaces. On the other hand, cells tend to spread and formed monolayer on poly-lysine coated PHB surface. When the PHB foams scaffolds were coated by poly-lysine, the seeding percentage of cells was also greatly enhanced.

3T3 Cells↗

PubMed2001

Point mutations of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies.

OBJECTIVE: To study the relation between point mutations at nt3243 and nt8344 of muscle mitochondrial DNA from patients with mitochondrial encephalomyopathies and phenotypes. METHODS: DNA was extracted from muscle specimens from 5 patients with mitochondrial encephalomyopathies and and amplified by PCR method, using corresponding oligonucleotide primers. DNA fragments were digested with restriction enzymes Bgl I and Apa I, then the digested DNA fragments were analyzed with an electrophoresis method. RESULTS: The point mutation at nt3243 of mtDNA was found in 2 patients, one with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) and another with myoclonic epilepsy with ragged red fibers (MERRF). The point mutation at nt8344 was found in 2 patients with MERRF, including the one with point mutation at nt3243. CONCLUSION: The point mutation of DNA at nt3243 correlated with MELAS and nt8344 correlated with MERRF. In addition, the detection of point mutations at both nt3243 and nt8344 in a patient with MERRF shows the association of mutation with diversity in clinical manifestations of mitochondrial encephalomyopathies.

Adolescent↗

PubMed2001

[Progress on the biosynthesis of medium-chain-length polyhydroxyalkanoates by microorganisms].

Polyhydroxylkanoates(PHAs) are a class of polyesters produced as reserve materials by a large number of microorganisms under metabolic stress. The most fascinating feature of PHAs is its degradability, and which is supposed to take place of the traditional plastics made from petroleum in the future. PHAs are divided into two classes: short-chain-length PHAs(scl-PHAs) and medium-chain-length PHAs. mcl-PHAs is more welcome owing to its more wide crystallinity and higher extension to break than scl-PHAs, especially when some kind of new functional groups were incorporated into the side chain of the polyester. Since Psedumonas oleovorans is the most typical microorganism to produce mcl-PHAs, here the author summarized how P. oleovorans synthesize the mcl-PHAs and the production of mcl-PHAs by fermentation and give some of the idea about the future research of this field.

Acyl Coenzyme A↗

PubMed2001

[The diagnostic value and limitations of total serum bile acid determined enzymatically].

OBJECTIVE: To elucidate the diagnostic value of total serum bile acid. METHOD: Clinical data from 913 cases was statistically analyzed with SPSS for Windows and other statistical procedures reported previously. RESULTS: (1) The mean of TBA of healthy subjects was (4.0 +/- 3.2) micromol/L. The TBA level of liver disease group is significantly higher than other group(P < 0.01). (2) The mean of TBA of patients with acute hepatitis was (167.2 +/- 132.4) micromol/L, the highest value was 449.5 micromol/L, it was significantly higher than other groups. TBA was a sensitive mark reflecting acute hepatic injury. (3) The sensitivity of TBA in patients with cirrhosis was 85.8%, higher than routine liver function tests. TBA is a valuable mark reflecting collateral circulation. (4) The sensitivity of TBA in mild chronic hepatitis was only 30.5%, much lower than ALT and TBIL (P < 0.01). (4) There was a relationship between the level of TBA and the severity of patients' condition, but the value of TBA for evaluating the severity was not as good as TBIL. CONCLUSION: The specificity of TBA is quite high, the sensitivity is moderate, TBA is valuable for the diagnosis of liver disease, especially for acute hepatitis and cirrhosis, but it's sensitivity for mild chronic hepatitis is only 30.5%, it is not as good as TBIL for evaluating the condition of patients.

Acute Disease↗

PubMed2001

[The role of insulin-like growth factor-I gene expression abnormality in pathogenesis of diabetic peripheral neuropathy].

OBJECTIVE: To explore the role of insulin-like growth factor-I (IGF-I) gene expression abnormality in neurotrophic causes of diabetic peripheral neuropathy. METHODS: Diabetes was induced in Sprague Dawley rats by alloxan. Various parameters were measured as follows: IGF-I mRNA by reverse-transcriptase polymerase chain reaction (RT-PCR), IGF-I peptide by enzyme-linked immunosorbent assay (ELISA), electrophysiological parameters of nerves by evoked electromyogram, morphometric evaluation of sciatic nerve under light microscope and transmission electron microscope. RESULTS: During the early diabetic stage, IGF-I mRNA (0.430 +/- 0.031 vs 0.370 +/- 0.016 +/- 0.280 +/- 0.010, P < 0.01, < 0.001) and IGF-I peptide contents [(0.430 +/- 0.031) ng/mg vs (30.06 +/- 3.60 +/- 23.71 +/- 2.70) ng/mg, P < 0. 01, < 0.001] in sciatic nerve tissue reduced in diabetic rats with hyperglycemia and varied with severity of diabetes. These parameters were further down regulated in diabetic rats with less duration of diabetes and non-diabetic control rats [IGF-I mRNA 0.320 +/- 0.021 - 0.230 +/- 0.060; IGF-I peptide (28.8 +/- 3.30 - 19.51 +/- 1.80) ng/mg]. They also correlated with nerve functional (sensory nerve conduction velocity: r = 0.714, P < 0.001, amplitude of evoked potentials: r = 0.716, P < 0.001, respectively) and structural abnormality (axonal size r = 0.81, P < 0.001) of the sciatic nerve. No difference was found in the above parameters between diabetic rats with euglycemia and non-diabetic control group. CONCLUSION: IGF-I gene expression in tissues was down-regulated from the early diabetic stage and the down-regulation varied with the severity and duration of diabetic state. The decrement in IGF-I level might contribute to the initiation and development of diabetic neuropathy via autocrine or paracrine pathway.

Animals↗

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

[Time for extubation and sequential noninvasive mechanical ventilation in COPD patients with exacerbated respiratory failure who received invasive ventilation].

OBJECTIVE: To discuss the optimal time for extubation and sequential non-invasive mechanical ventilation in COPD patients with exacerbated respiratory failure who received invasive ventilation. METHODS: 24 patients received invasive ventilation for 3 days were randomly assigned to receive noninvasive ventilation (study group) or to continue the weaning process with invasive ventilation (control group). The incidence of ventilator-associated pneumonia (VAP), the incidence of death, the duration of ventilation, the hospitalization were analyzed in two groups. RESULTS: Between study group and control group, the incidence of VAP was 0/12 vs 7/12, P = 0.027; the incidence of death was 0/12 vs 3/12, P = 0.217; the continued duration of ventilation after invasive ventilation for 3 days was (7 +/- 5) days vs (15 +/- 12) days, P < 0.05; the hospitalization was (16 +/- 6) days vs (25 +/- 12) days, P < 0.05, respectively. CONCLUSIONS: In COPD patients with exacerbated respiratory failure who received invasive ventilation, invasive ventilation for 3 days followed by noninvasive ventilation may decrease the incidence of VAP, shorten the duration of ventilation and hospitalization.

Aged↗

PubMed2001

[Effect of intratracheally administered IL-12 recombinant adenovirus on ovalbumin induced bronchial hyresponsiveness in mouse model].

OBJECTIVE: To assess the effect of intratracheally administered IL-12 recombinant adenovirus (Adm IL-12) on ovalbumin (OVA) induced bronchial hyperresponsiveness in mouse model. METHODS: C57BL/6 mice were sensitized by ovalbumin. Adm IL-12 with the dose of 10(8)pfu/mouse was administered intratracheally before OVA challenge. IL-4, IL-5 and IFN-gamma in BALF, bronchial responsiveness, eosinophil count in peripheral blood and BALF, serum total IgE and specific IgE were measured. RESULTS: There was IL-12 gene expression in the lung tissue after Adm IL-12 administration, concentration of IL-12 in sera and BALF were (540 +/- 60) U/ml and (4 700 +/- 800) U/ml respectively, but were unable to be detected in control group (P < 0.01). Compared with the control group, there were significantly lower levels of IL-4 [(3.5 +/- 2.0) ng/ml vs (85.0 +/- 25.0) ng/ml] (t = 27.97, P < 0.01) and IL-5 [(6.5 +/- 4.5) ng/ml vs (54.0 +/- 14.0) ng/ml], (t = 7.92, P < 0.01) in BALF, accompanying with a higher level of IFN-gamma [(690.0 +/- 32.0) ng/ml vs (12.5 +/- 3.2) ng/ml] (t = 51.6, P < 0.01), lower airway resistance [(360 +/- 30) cm H(2)O vs (810 +/- 50) cm H(2)O] (t = 18.9, P < 0.01) and lower eosinophil counts in both peripheral blood [(0.7 +/- 0.1)% vs (9.2 +/- 0.5)%] (t = 47.1, P < 0.01) and in BALF [(3.5 +/- 0.7) x 10(4)/ml vs (21.6 +/- 4.7) x 10(4)/ml)] (t = 9.33, P < 0.01). However, neither serum total IgE [(65 +/- 9) microgram/ml vs (67 +/- 10) microgram/ml], nor specific IgE [(32 +/- 8) microgram/ml vs (33 +/- 8) microgram/ml] showed significant difference (all P > 0.05). CONCLUSIONS: Intratracheally administered Adm IL-12 inhibits ovalbumin induced airway hyperresponsiveness, which may be an effective approach in the management of antigen induced bronchial asthma.

Adenoviridae↗

PubMed2001

[Environmental impact of oil pollutant on groundwater during oilfield exploitation in Daqing--a modelling analysis].

This paper analyzed the pollution sources and paths of groundwater environment in Longnan of Daqing during oilfield exploitation. Based on the technological characteristics of oilfield exploitation, a mathematical model on the migration and transformation of oil pollutants was developed, in which, the degradability and the adsorption capacity of oil pollutants were taken into account. An analytical formula of oil pollutant migration in groundwater was derived with continuous sources, and a prediction on the migration was made, which provide an important basis for the environmental impact assessment of oilfield exploitation project.

Industrial Oils↗

PubMed2001

[Photosynthetic characteristics of two plagiomnium mosses in summer and winter].

A comparative study on the photosynthetic characteristics of Plagiomnium acuium(Lindb.) T. Kop. and P. maximoviozii(Lindb.) T. Kp., two overwintering host mosses for Chinese gall aphid(Schlechtendalia chinensis), was conducted by using CI-301PS in Summer and Winter. The results showed that the photosynthetic capacity of these two mosses species was 125.67 and 94.63 mumol CO2.kg-1DW.s-1 in Summer, and 58.1 and 62.1 mumol CO2.kg-1DW.s-1 in Winter, respectively. The dark respiration rates of these two species in Summer significantly exceeded those in Winter. The light complementary point of these two mosses species was in the range from 20 to 40 mumol.m-2.s-1, and light saturated point was from 200 to 400 mumol.m-2.s-1, with higher value in Summer and lower value in Winter. Their apparent quantum yields were 1.535 and 1.559 in Summer, but only 0.456 and 0.459 in Winter. The optimum temperature for photosynthesis of these two mosses species was 20 to 35 degrees C, also higher in Summer and lower in Winter. No matter which species and growing season, the temperature coefficients(Q10) measured in the range of 0-20 degrees C were similar, ranging from 1.15 to 1.23. These two moss species could maintain a certain net photosynthesis for 10-30 minutes under temperature stress from -15 to -10 degrees C and from 40 to 45 degrees C.

Animals↗

PubMed2001

[Effects of soil water condition and microclimate on transpiration rate of rice].

The transpiration rate and water use efficiency (WUE) of rice were studied under high, moderate and low soil water conditions (treatments A, B and C) in the red soil area of southern China. Diurnal variation of transpiration showed that rice transpiration rate was influenced by several microclimatic factors in the field. Correlation analysis and stepping multi-regression analysis suggested that the difference of relative humidity between leaf and air, and the leaf temperature were the two main factors affecting the transpiration rate of rice. The results also showed that WUE was and yield were increased significantly in treatment B. While in treatment C, the WUE increased, but the yield of late rice decreased. The transpiration rate of early rice was decreased under moderate and low soil water treatments, but this did not happen to late rice.

Ecosystem↗

PubMed2001

[The status quo survey of false and inferior species in Chinese medicinal materials market in Hubei Province].

By taking a sample, unqualified varieties were investigated found in Chinese medicinal material examinatorial work near twenty years of six regional level and three countrylish level institutes for drug control and one comprehensive level-three grade-A hospital. By mail, false and inferior species and their origin of Chinese medicinal material were investigated found by sixteen institutes for drug control near ten years in Hubei province. 539 kinds of adulterants (750 cases) including 24 toxic species were found in above-mentioned investigations. Fales and inferior species are rampant in minority regions, which threatens people's health severely. It is urgent for supervising department to gorem the condition strictly.

Drugs, Chinese Herbal↗

PubMed2001

Observation of wounding characteristics in dogs wounded by super velocity projectile.

OBJECTIVE: To understand wounding characteristics in dogs wounded by super velocity projectile with a purpose of providing a basis for prevention and treatment of such wounds. METHODS: A specially-made explosive gun was used to shoot aluminium bullet weighing 3.0 g and 1.4 g to injure both legs of dogs at velocities of 2330 m/s, 3200 m/s and 4250 m/s, respectively, and the soap specially made was also shot. At the same time, steel ball of 1.03 g was shot with a Type 53 smooth chamber gun at a speed of 1280 m/s. Within 30 min after wounding, debridement and pathological anatomy were performed and specimens were taken for light microscope observation. RESULTS: When the dogs were wounded by the 3 g bullet at speed of 2330 m/s, the entrance of the left leg was penetrated explosively with a defect area of 225 cm(2), and the femur trunk was also injured and the residual femur had comminution fracture. The exit of the right leg was blindly wounded with a defect area of 63 cm(2), but only the skin was not penetrated. Both testes and part pelvis were injured too. Under light microscope, degenerative myofibers and bleeding of the spatium between the myofibers could be found at the place 4 cm away from the wounding track. Furthermore, serious bleeding of the bladder and blood vessels of the brain could be observed. The lungs showed changes of blast injury. Vacuolar change was presented in the cytoplasm of hepatocytes. Injuries of the animals in other two experimental groups were similar to those described above, but the defect area of the wounded track was 124 cm(2) in the group of 4250 m/s. Injuries caused by the steel ball were milder than caused by the explosive gun. The volume of the residual cavity in the soap was 5000 ml. CONCLUSIONS: The super-velocity projectile causes destructive damage to the local tissues and multi-organ injuries. Therefore, the practical medical care needs not only amputation but also management of multi-organ injuries.

Animals↗

PubMed2001

Temporal bone fracture and its complications.

OBJECTIVE: To explore the characteristics and treatment of temporal bone fractures and injuries in the medial-inner ear. METHODS: The clinical data of 48 cases of temporal bone fractures admitted to our hospital from January 1989 to November 1999 were retrospectively analyzed. RESULTS: Forty-eight patients with temporal bone fractures accounted for 17.00% of the homochronous craniofacial fractures. Of the 48 cases, temporal bone fractures induced by traffic accidents accounted for 66.67%, capillary fractures for 93.75%, medial inner ear injuries or craniocerebral injuries for 77.08% and hearing loss or tinnitus for 48.00%. The cerebrospinal fluid (CSF) otorrhea and facioplegia accounted for 36.70% and 3.00%, respectively, in the longitudinal fractures, while they were 25.00% and 37.50%, respectively, in the transversal fractures. Primary emergent operations were performed on 46 cases and neurosurgery accounted for 46.00%. Secondary procedures accounted for 16.70%. As a result, 43 cases survived (89.58%) and 5 died (10.41%). CONCLUSIONS: Traffic injury is the first high-dangerous factor for temporal bone fractures, which are often complicated with medial-inner ear or craniocerebral injury. The CSF otorrhea is common in the longitudinal fractures and facioplegia is common in the transversal fractures. The key step is to rescue the life, keep the airway unobstructed and maintain the circulation in the primary emergency treatment.

Adolescent↗

PubMed2001

Impairment of non-specific immunity in patients under persistent vegetative state resulting from trauma.

OBJECTIVE: To investigate the immune response in patients under persistent vegetative state (PVS) resulting from trauma. METHODS: Peripheral blood monocytes were obtained from 12 PVS patients (Group PVS)and individuals in normal control group by density gradient centrifugation; the enzyme linked immunosorbent assay kit was then used to measure monocyte HLA-DR antigen expression on the surface of peripheral blood monocytes before and after monocyte activation with either IFN-gamma or LPS. RESULTS: Compared with normal control group, the peripheral blood monocyte HLA-DR antigen expression in the Group PVC fell significantly in PV S patients (P<0.001); the level of HLA-DR antigen express ion on the monocyte surface rose notably after stimulation with either IFN-gamma or LPS (P<0.01). As for PVS patients, it was still difficult to restore to normal (P<0.05). CONCLUSIONS: The level of HLA-DR antigen expression on the sur face of peripheral blood monocytes in PVS patients decreases obviously. Therefore, the function of non-specific immunity in PVS patients is suppressed.

Adult↗

PubMed2001

[Breast reconstruction with a TRAM flap].

OBJECTIVE: Breast reconstruction with a transverse rectus abdominis myocutaneous (TRAM) flap was performed to enhance the mental and physical well-being of patients. METHODS: The experience with TRAM breast reconstruction in 42 patients was reviewed. The patient selection, flap design and our operative technique were introduced in detail. RESULTS: TRAM breast reconstruction was performed as immediate reconstruction in 25 patients, as delayed reconstruction in 17 cases. 2 cases had partial skin necrosis in the abdominal donor site. 2 had partial necrosis of the TRAM flap. One patient had abdominal hernia. CONCLUSIONS: The additional vascular anastomosis or double-pedicle TRAM flap with intramuscular dissection was the key points to reduce complications. Due to the difficulty of TRAM flap reconstruction, thorough understanding of the technique and surgical accuracy are necessary for both flap safety and aesthetic pleasing results.

Adult↗

PubMed2001

[A primary clinical analysis of artificial bone implantation of cleft palate].

OBJECTIVE: To observe whether repairing the hard palate can improve velopharyngeal function. METHODS: 40 patients with hard palate cleft were randomly divided into two groups: the control group and the implantation group. Each group had 20 patients. The patients in the implantation group were implanted with compound artificial bone of HA--Bone cement. All patients hag been followed up for three months postoperatively. The patients in the repaired group were examined using computer tomography. All patients were examined using NPF. RESULTS: The implanted artificial bone had no rejection. The computer tomography showed that the implanted artificial bone in hard palate had no shifting, subsidence or breakage. The movement of soft palate of the implantation group was greater than the control group. The velopharyngeal function of the implantation group was much better than the control group. CONCLUSION: Repairing the hard palate cleft with artificial bone can improve velopharyngeal function.

Biocompatible Materials↗

PubMed2001

[Primary research about reconstruction of cornea in three-dimensional collagen gel in vitro].

OBJECTIVE: To research the reconstruction of cornea in three-dimensional culture. METHODS: Using primary cultured corneal epithelial cells, stromal cells and endothelial cells rebuilt a corneal structure in three-dimensional collagen gel reconstruction system. The artificial corneal transparency was examined by a slit-lamp microscope. The biological characters of cells were tested by routine pathologic and transmission electron microscopic technology. RESULTS: The reconstructed corneal tissue formed three layers. The epithelial cell layer was two or three cell thickness. The endothelial cells formed a single layer. The stromal cells were diffuse in distribution in the collagen gel. The cells had proliferative ability and capability of producing collagen. CONCLUSION: The regular and transparent corneal structure can be rebuilt by tissue engineering technology.

Cells, Cultured↗