Biomedical subjects

Y Yuan

Publications and source records attributed to Y Yuan.

At least 109 records · Page 6Linked to original sources

PubMed2000

Pulmonary function changes following surgical correction for pectus excavatum.

OBJECTIVE: To assess whether and to what extent pulmonary function returns to normal after surgical correction for pectus excavatum. METHODS: Twenty-seven patients who could be examined in person at the outpatient department of our hospital were included in this study. Of these patients, 24 were boys and 3 were girls, with age ranging from 3 to 16 years (mean: 8.67 years). The mean age at surgery was 4 years and mean years at follow-up was 6.8. Pulmonary function measurements included inspiratory vital capacity (IVC), total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC), RV/TLC ratio, maximal voluntary ventilation (MVV), forced ventilatory capacity (FVC), forced expiratory volume in one second (FEV1), maximal mid-expiratory flow (MMEF), maximal expiratory flow at 75% vital capacity (V75), maximal expiratory flow at 50% vital capacity (V50), maximal expiratory flow at 25% vital capacity (V25) and breathing reserve ratio (BR). RESULTS: TLC, FRC, MVV, MMEF, V75 and V50 were not different from normal values. IVC, FVC, FEV1 and V25 were significantly decreased compared with normal values. RV and RV/TLC were high in 87.5% cases. CONCLUSIONS: Preoperative symptoms improved substantially after operation. Little airway obstruction was observed postoperatively, suggesting that patients with pectus excavatum should have surgery as early in life as possible, preferably by age 3.

Adolescent↗

PubMed2000

Relationship between serum or tissue ouabain and blood pressure in 1k1c hypertensive rats.

OBJECTIVE: To evaluate the role of endogenous ouabain (EO) in the development of hypertension and the characteristics of EO secretion in 1k1c (one kidney, one clipped) hypertensive rats. METHODS: EO content of serum and tissues in 1k1c hypertensive rats and normal control Sprague-Dawley (SD) rats was detected by the method of enzyme linked immunosorbent assay (ELISA). The relationship between serum or tissue ouabain and blood pressure was analyzed in 1k1c hypertensive rats. RESULTS: The ouabain content of serum, heart, kidney, adrenal gland, pituitary and hypothalamus was significantly higher in 1k1c hypertensive rats than that in normal control SD rats (2.25, 2.63, 3.35, 40.37, 3.34, 15.7 micrograms/kg tissue in 1k1c hypertensive rats vs 1.12, 1.79, 1.73, 27.54, 1.83, 10.10 micrograms/kg tissue in control SD rats, respectively. P < 0.05 for all of these comparisons). The ouabain content of the adrenal gland and the hypothalamus was higher than that of other tissues or serum, both in 1k1c rats and in control SD rats. The EO content of serum, kidney and hypothalamus was significantly correlated with blood pressure in 1k1c hypertensive rats (r = 0.59, 0.63, 0.52, respectively. P < 0.05). The ouabain content of heart, liver, adrenal gland and pituitary was not correlated with blood pressure. CONCLUSIONS: EO might play an important role in the development of hypertension in 1k1c hypertensive rats. The adrenal gland may be a major source of EO and the hypothalamus-pituitary-adrenal axis may be involved in the regulation of EO secretion.

Animals↗

PubMed2000

The role of c-myc in regulating mdr1 gene expression in tumor cell line KB.

OBJECTIVE: To investigate the relationship between c-myc expression and mdr1 regulation in multidrug resistance (MDR) tumor cell line KBv200. METHODS: A DNA sequence encoding the ribozyme gene was incorporated into a eukaryotic expression vector (pH beta Apr-1 neo) and transfected into the cell line KB, which is resistant to vincristine and expresses the MDR phenotype. The changes of c-myc protein, P-glycoprotein (P-gp) and c-myc mRNA in the KB cell line were assessed before and after treatment with anti-mdr1-ribozyme using immunohisto-chemistry, flow cytometry and semi-quantitative RT-PCR methods. RESULTS: The results demonstrate elevated levels of c-myc mRNA and c-myc protein as well as P-gp in KBv200 cells which are resistant to vincristine (VCR), compared to these of the KB cell which is not resistant to VCR. The expression of c-myc protein, P-gp and c-myc mRNA in the multidrug resistant cell, KBv200, displayed higher than that in the sensitive cell, KB. However, after reversing the multidrug resistance phenotype by anti-mdr1-ribozyme, the level of c-myc protein, P-gp and c-myc mRNA expression showed significant down-regulation in KBv/5 mR3, without difference in KB/5 mR3 and KB. CONCLUSION: The results of our study suggest that there is a close relationship between c-myc gene and mdr1 gene. c-myc may be involved in regulating the expression of mdr1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

[Preliminary investigation of effect of serum leptin on nutritional state of COPD patients].

OBJECTIVE: To explore the significance of serum leptin and TNF-alpha in malnutrition of COPD. METHODS: Serum leptin and TNF-alpha concentrations were measured by radioimmunoassay. Body mass index (BMI), percent normal body weight (NW%), triceps skin-fold thickness (TSF), subscapular skin-fold thickness (SSF), mid-upper arm circumference (MAC), serum albumin (ALB) and total lymphocytes count (LYM) were determined in 31 patients with COPD and in 11 healthy controls. The correlation between leptin and nutritional parameters was analysed. RESULTS: (1) Serum leptin concentrations (3.0 +/- 2.5) micrograms/L in 42 subjects were significantly correlated with BMI, NW%, TSF, SSF and MAC (P < 0.001). (2) Serum leptin concentrations were significantly correlated with BMI in both malnourished patients with COPD and non-malnourished patients (P < 0.05-0.001). The leptin level was significantly lower in malnourished group (1.3 +/- 1.0) micrograms/L than in non-malnourished group (4.5 +/- 2.6) micrograms/L, (P < 0.05). The differences in serum leptin level and BMI between non-malnourished group and healthy group were not significant. (3) Serum TNF-alpha level was significantly higher in COPD group (1.8 +/- 0.3) micrograms/L than in healthy group (1.0 +/- 0.5) microgram/L (P < 0.05). Serum leptin levels didn't significantly correlate with TNF-alpha levels in COPD patients. CONCLUSION: Serum leptin levels correlate with nutritional parameters in COPD patients and leptin may contribute to the malnutrition in COPD patients.

Aged↗

PubMed2000

[Low-molecular-weight heparin for preventing deep-vein thrombosis after total joint arthroplasty].

OBJECTIVE: To evaluate the efficacy and safety of low-molecular-weight heparin (LMWH) in preventing deep-vein thrombosis (DVT) after total hip and knee replacement (THR, TKR). METHODS: From November 1997 to March 1999, we performed total joint replacement for 47 control patients (34 knees, 28 hips) and for 31 patients (19 knees, 17 hips) who had been given low-molecular-weight heparin for preventing deep-vein thrombosis. All patients received venography of the operated limbs after operation. RESULTS: DVT occurred in 19.4% of the LMWH patients (26.3% in TKR, 11.8% in THR) and the reduction was significant (P < 0.05) compared to the control group (48.4%, 55.9%, 39.3% respectively). The incidence of proximal DVT was also reduced significantly (P < 0.05) from 19.4% of the control group to 2.8% of the LMWH group. CONCLUSION: Low-molecular-weight heparin can significantly reduce the incidence of deep-vein thrombosis after total joint replacement.

Arthroplasty, Replacement, Hip↗

PubMed2000

[Changes in myelin sheath and axon of spinal cord in X-irradiation injured rats].

OBJECTIVE: To investigate the X-irradiation effect on the myelin sheath and axon of the spinal cord. METHODS: 60 Wistar adult rats receiving hemisection in the thoracic spinal cord were made into models of spinal injury. Among these rats, 30 in the test group received X-irradiation of 35-Gy the day after operation, while 30 in the control group only received hemisection. Operative spinal cord was subjected to immunohistochemistry and hyper-microscopic observation. RESULTS: In the test group, injury to the myelin sheath of the upper and lower lesion and the number of neuro-fibrotic positive axon increased. In the control group the number of myelin sheath below the injured section decreased. Under electronic microscope, demyelination was found in the spinal cord and new-born tiny neuro-fibrotic tracts were seen below the lesion. CONCLUSIONS: X-irradiation can make spinal cord demyelinate and promote the increase of neuro-fibrotic positive axon.

Animals↗

PubMed2000

[Clinical analysis of 13 infected total knee replacements].

OBJECTIVE: To investigate the cause, treatment and its result of infected total knee replacements (TKRs). METHODS: Between 1987 and 1999, 13 infected TKRs in 13 patients were treated with surgical debridement and one-stage or two-stage reimplantation. The preoperative average ROM of knees was 55 degrees and the average Hospital for Special Surgery (HSS) knee score was 36.5 points. Clinical results were evaluated after average follow-up for 3 years and 5 months. We analyzed the factors for TKR infection. RESULTS: No recurrent infection was noted, and pain was significantly alleviated in all patients. The average ROM of knees was 85 degrees and the average HSS knee score was 73.5 points. CONCLUSIONS: The high risk factors for TKR infection are rheumatoid arthritis, steroid administration, associated diabetes mellitus, hinged prosthesis and previous knee surgery. Early surgical debridement with intravenous antibiotics is necessary as soon as deep infection is detected. Two-stage reimplantation is more effective in eradicating deep infection than single debridement or one-stage reimplantation.

Adult↗

PubMed2000

[Long-term follow-up results of microsurgical treatment for glossopharyngeal neuralgia].

OBJECTIVE: To discuss effective surgical methods for the treatment of glossopharyngeal neuralgia. METHODS: During 1986 - 1998, 21 patients with glossopharyngeal neuralgia were treated microsurgically. Of whom, 5 patients were treated by microvascular decompression (MVD), 4 by MVD combined with rhizotomy of glossopharyngeal nerve root and upper 1st to 2nd rootlets of vagus nerve root, and 12 by rhizotomy of glossopharyngeal nerve root and upper 1st to 2nd rootlets of vagus nerve root. RESULTS: Neuralgia disappeared in all patients postoperatively. In 3 patients, occasional coughing episodes occurred postoperatively. One of the 3 patients also suffered from mild hoarseness and swallowing difficulty. All patients were followed up on average 7.2 years with no recurrence. CONCLUSIONS: MVD, rhizotomy of glossopharyngeal nerve root and upper 1st to 2nd rootlets of vagus nerve and their combination are effective for the treatment of glossopharyngeal neuralgia. Operative methods should be chosen according to the following two points: compression of nerve roots by affected vessels or not; and the condition of compression.

Adult↗

PubMed2000

[Reconstruction of hip, knee, and ankle bony fused in non-functional position of ankylosing spondylitis patients].

OBJECTIVE: To evaluate the reconstruction of hip, knee and ankle joints with bony fusion at non-functional positions for patients with severe late-stage ankylosing spondylitis (AS). METHODS: From January 1996 to May 1997, simultaneous ipsilateral total hip, knee and ankle replacement was performed under single anesthesia on 2 patients (3 sides) with multiple joint deformity including bony fusion at non-functional positions. They were followed for 29 months on average. RESULTS: Satisfactory range of motion and function were observed. HSS knee score on average was improved by 45 points and Harris hip score by 37.7 points. There were no wound healing problems or late infection. No aseptic loosening was found. CONCLUSIONS: Simultaneous ipsilateral total hip, knee and ankle replacement not only reduced cost for hospitalization, but also facilitated early rehabilitation. To our knowledge, this is the first report on this type of surgery, named ipsilateral tri-arthroplasty.

Adult↗

PubMed2000

[Graf's ultrasound examination method in assessment of dysplasia and congenital dislocation of infant hip].

OBJECTIVE: To discuss the application of Graf's sonographic method in assessment of developmental dysplasia and dislocation of infant hip. METHODS: 2258 infants (4516 hips) were examined and evaluated by Graf's method. RESULTS: The analysis of data showed that type I hip accounted too 78.99%, type II 20.56%, and type III and type IV 0.45%. CONCLUSION: Graf's method can provide qualitative and quantitative evaluation for hips of infants in 3 months after birth. It is an effective in developmental dysplasia of the hip (DDH) and is also useful for early treatment and follow-up of DDH.

Female↗

PubMed2000

[A comparative study on the expressions of IL-4, IFN-gamma and TNF-alpha in BMMNC of acute and chronic aplastic anemia patients].

OBJECTIVE: To detect the induced levels of IL-4, IFN-gamma and TNF-alpha in the supernatant of bone marrow mononuclear cells (BMMNC) and compare the difference of immune status between acute (SAA) and chronic (CAA) aplastic anemia patients. METHODS: Concentrations of IL-4, IFN-gamma and TNF-alpha in PHA-P-induced BMMNC supernatants were determined by ELISA assay in 11 SAA and 13 CAA patients as well as 16 controls. Concentration differences between the two groups were compared. RESULTS: (1) The IFN-gamma and TNF-alpha levels in AA patients studied were much higher than that in controls, and IL-4 levels were normal in SAA group but elevated in CAA group. (2) TNF-alpha levels were comparable between the two AA groups, but both IL-4 and IFN-gamma levels were significantly different between them. CONCLUSION: Enhanced cellular immunity seems to play an important role in the pathogenesis of SAA, and enhancement of both cellular and humoral immunity might contribute to the pathogenesis of CAA.

Acute Disease↗

PubMed2000

[Comparison of efficiency and merits of two parameters for bronchial challenge test by use of a simple equation].

The aim of this study was to investigate the relationship, merit and weakness of two parameters--the FEV1 and sGaw--for bronchial challenge test. The 36 cases of asthma patients were subjected to bronchial challenge test with FEV1 and sGaw as the test parameters simultaneously. A simple calculative equation was used. The Mch (challenge medicine) concentrations for a 20% decrease of FEV1(PC20FEV1) and for a 35% decrease of sGaw (PC35 sGaw) were figured out. The results showed that PC20 FEV1 and PC35 sGaw were 2.73 +/- 2.92 g/L and 1.50 +/- 2.03 g/L respectively. A significant difference between them was noted (P < 0.05), and their coefficient of correlation r = 0.738. The linear regression equation was PC35sGaw = 0.100 + 0.513 x PC20 FEV1. PC35sGaw was obviously lower than PC20 FEV1; the Mch amount for PC35sGaw was almost one half of that for PC20 FEV1, which indicated that sGaw was more sensitive than FEV1 as a parameter for bronchial challenge test. The FEV1, however, needs a relatively low standard of instrument, so it is more obtainable and popularized.

Adult↗

PubMed2000

[The measurement of tracheo-bronchial mucociliary clearance by technetium-99m DTPA aerosol scintigraphy].

Mucociliary clearance of respiratory channels is one of the important mechanisms guarding against retention of foreign particles within the lungs. Thus objective assay of the system is essential to recognizing and understanding its abnormalities. In this study, 18 healthy subjects and 32 patients with chronic obstructive pulmonary diseases (COPD) were examined by technetium-99m-DTPA aerosol scintigraphy. Monitoring was performed by visual inspection (cinescintigraphy) and quantitative analysis. The mucociliary clearance rates of 18 healthy subjects and 32 COPD patients were 3.89 +/- 0.92 mm/min and 1.32 +/- 0.59 mm/min respectively. Statistical analysis indicated that the airway clearance rate and mucociliary clearance rate of COPD patients were significantly lower than those of normal subjects (P < 0.01). The method of assay reported here is simple and objective. It has not only the advantage of visual inspection and quantitative analysis, but also the potential usefulness in studying other bronchial diseases and evaluating therapeutic effectiveness of drugs.

Adult↗

PubMed2000

[Application of model 4650 type I compressor atomizer in bronchial challenge test].

This study was directed to the feasibility of applying a simple atomizer-model 4650 type I (abbrev. M)-to bronchial challenge test. 92 cases of asthma were divided into 3 groups randomly. All of them were subjected to the bronchial challenge test by M atomizer, and by standard Dosimeter atomizer (abbrev. D) as a comparison. In the test by M atomizer, the times for inspiring challenging medicine were 1, 1.5 and 2 minutes for the 3 groups respectively, while the time for D atomizer was 1 minute for all. The results showed no significant differences (P > 0.2-0.5) between the two atomizers in the 3 groups, their values were linear correlated. When the inspiring time was 1 minute for both M and D, the test needed a higher concentration of challenging medicine for M than for D, their coefficient of correlation (r = 0.285) was relatively low. When inspiring time postponed to 1.5 minute for M, the difference in medicine concentration between M and D was smallest (-0.075 g/L), r = 0.665. However, a further postponed inspiring time to 2 minute for M reversely broadened their difference. These results indicated that the efficiency of M atomizer was a little lower than that of D, postponing the inspiring time for M could make up this weakness. A 1.5 minute inspiring time for M atomizer was the suggestion. Some modifications on M atomizer were done by us for a better efficiency, and the cheap and popular M atomizer could be a good replacement in bronchial challenge test.

Adolescent↗

PubMed2000

[Determination of ochratoxin A by ELISA].

The determination of ochratoxin A by Enzyme-linked immunosorbent assay (ELISA), including the method of preparation of antigen and antibody, and the promising of ELISA in mycotoin determinations was introduced.

Enzyme-Linked Immunosorbent Assay↗

PubMed2000

[Raman spectra of the serums from cancerous persons].

The serums of different categories, those who are normal people and those who are patient suffering from nasopharyngeal cancer, liver cancer and chronic leukaemia, were determined by laser Raman spectra at the range of 0-2,000 cm-1. The results demonstrated that the serums of those who are suffering from the same disease show different characteristic peak height, but their Raman spectrogram characteristics are almost the same. There exists great difference in the laser Raman spectrogram for the serums of the different kinds of cancerous patients. Near the characteristic peaks of laser Raman spectrograms of serums from the cancerous patients, the normal person's serum has no Raman spectrogram characteristic peak.

Humans↗

PubMed1999

The von Willebrand factor-glycoprotein Ib/V/IX interaction induces actin polymerization and cytoskeletal reorganization in rolling platelets and glycoprotein Ib/V/IX-transfected cells.

Platelet adhesion to sites of vascular injury is initiated by the binding of the platelet glycoprotein (GP) Ib-V-IX complex to matrix-bound von Willebrand factor (vWf). This receptor-ligand interaction is characterized by a rapid on-off rate that enables efficient platelet tethering and rolling under conditions of rapid blood flow. We demonstrate here that platelets adhering to immobilized vWf under flow conditions undergo rapid morphological conversion from flat discs to spiny spheres during surface translocation. Studies of Glanzmann thrombasthenic platelets (lacking integrin alpha(IIb)beta(3)) and Chinese hamster ovary (CHO) cells transfected with GPIb/IX (CHO-Ib/IX) confirmed that vWf binding to GPIb/IX was sufficient to induce actin polymerization and cytoskeletal reorganization independent of integrin alpha(IIb)beta(3). vWf-induced cytoskeletal reorganization occurred independently of several well characterized signaling processes linked to platelet activation, including calcium influx, prostaglandin metabolism, protein tyrosine phosphorylation, activation of protein kinase C or phosphatidylinositol 3-kinase but was critically dependent on the mobilization of intracellular calcium. Studies of Oregon Green 488 1, 2-bis(o-amino-5-fluorophenoxy)ethane-N,N,N',N-tetraacetic acid tetraacetoxymethyl ester-loaded platelets and CHO-Ib/IX cells demonstrated that these cells mobilize intracellular calcium in a shear-dependent manner during surface translocation on vWf. Taken together, these studies suggest that the vWf-GPIb interaction stimulates actin polymerization and cytoskeletal reorganization in rolling platelets via a shear-sensitive signaling pathway linked to intracellular calcium mobilization.

Actins↗

PubMed1999

Intra-A chain disulphide bond forms first during insulin precursor folding.

In this study, we investigated the folding pathway of insulin precursor and compared it with that of insulin-like growth factor I (IGF-I). The intra-A chain disulphide bond was found to form early in insulin precursor folding, whereas the corresponding disulphide bond in IGF-I formed late. Intra-A chain disulphide-bond deleted [A6, A11-Ser] proteins, including proinsulin, insulin, and A chain, were employed for this investigation. Under the same conditions the recombination yield of insulin from S-sulphonates of native A and B chains was 22%, while the yield of [A6, A11-Ser] insulin from S-sulphonates of [A6, A11-Ser] A chain and native B chains was only approx. 7%. This indicated that the intra-A chain disulphide bond may serve to stabilize the A chain folding intermediate so as to facilitate the correct recognition and pairing with the B chain. Time courses of oxidation of reduced insulin A chains, reduced A and B chains, and reduced proinsulins showed that the intra-A chain disulphide bond formed first during insulin precursor folding. The formation of intra-A chain disulphide bond further accelerated the formation of the other two inter-chain disulphide bonds. The time course of helix structure formation of insulin A chains also indicated that the intra-A chain disulphide bond formed first, and could stabilize partially folded A chain helix structure. The rate of intra-A chain disulphide bond formation was almost the same as that for both helix structure formation and insulin molecule formation, indicating that the formation of the intra-A chain disulphide bond was the rate limiting step for the folding of insulin precursor.

Circular Dichroism↗