Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 775 records · Page 43Linked to original sources

PubMed1997

[Effects of aerobic exercise on regulation of activities of hepatic low density lipoprotein receptor in hypercholesterolemic rats].

The present study is to determine the effects of exercise on the regulatory role in activities of hepatic low density lipoprotein receptor (LDL-R) in experimental hypercholesterolemic (HC) rats. Using a specific assay for the binding of 125I-LDL receptor to homogenate, the activity of hepatic LDL-R were measured. It was observed that the activity of LDL-R in HC decreased by 37% as compared with the normal control (NC) rats. HC rats also had a higher levels of serum total cholesterol (TC), LDL-Cholesterol (LDL-C) and apolipoprotein B (Apo B). The rats fed on high-cholesterol diet combined with exercise for 12 weeks (HE) had lower TC, LDL-C and Apo B levels than those of HC rats, and had a higher hepatic LDL-R activity which was 26% higher than that of HC rats. These finding suggested: (1) LDL-R activity may be regulated downward in cholesterol-loaded rats; (2) Exercise may enhance the utilization and degradation of intracellular cholesterol, and may have a feedback effect on the down-regulated synthesis of LDL-R, thus increase the uptake of LDL-C and lower plasma level of lipid.

Animals↗

PubMed1997

[Determination of the selenomethionine content in grain and human blood].

The authors used the method of cyanogen bromide-fulorimetry to determine the trace amounts of bound selenomethionine (SeMet) in corn, rice, wheat, soybean and human blood. The contents of SeMet in corn samples were found to be 9.2-19014.1 ng/g, and 45.5% to 82% of the total Se in corn samples were in the form of SeMet. Like corn, the proportion of Se in the form of SeMet in total Se in rice, wheat and soybean were 54.9%-86.5%, 50.4%-81.4% and 62.9%-71.8% respectively. The results showed that SeMet is the major chemical form of Se in grain samples determined. The contents of SeMet in two human blood samples (Se content 56.4 ng/g and 71.8 ng/g) were determined as 28.3 ng/g and 53.4 ng/g respectively.

Edible Grain↗

PubMed1997

[Primary clinical experience of neuroendoscopy: report of 19 cases].

10 cases of basal ganglion and 6 of subcortical hematoma were evacuated. One case of temporal and 2 cases of para- and intra-ventricle arachnoid cyst were fenestrated towards the cistern or lateral ventricle. Burred holes were near the lesion, through which endoscope should run. We guided the endoscope to the target by stereotatic equipment in 10 cases of basal ganglion hematoma and 1 case of ventricle arachnoid cyst, and introduced endoscope by free-hand in other cases. Hematoma group: CT reexamination within 48 hours showed that the residual hematoma was less than 20%-30% in 9 of 11 cases. Cyst group: symptoms of all cases of arachnoid cysts were alleviated after intervention. CT after a month showed that fenestration entrance could be seen clearly in 2 cases. The cyst reduced 20%-30% in 1 case. There were no direct complications in the group. It was shown that operation by endoscope is minimal invasive and little complicated.

Adolescent↗

PubMed1997

[Clinical evaluation of serum transforming growth factor beta 1 assay in the diagnosis of primary hepatic carcinoma].

Serum transforming growth factor beta 1 (TGF beta 1) concentration was determined in 47 patients with primary hepatic carcinoma (PHC) and 77 patients with various liver diseases and gastrointestinal tumors by means of enzyme-linked immunosorbent assay system. The result revealed that serum TGF beta 1 level of PHC patients were significantly higher (257.6 +/- 126.0 micrograms/L) than those in normal subjects (81.5 +/- 43.5 micrograms/L), in patients with hepatitis (152.4 +/- 98.4 micrograms/L), cirrhosis (191.8 +/- 96.3 micrograms/L), hepatic benign tumor (91.9 +/- 37.9 micrograms/L), metastatic liver cancer (146.4 +/- 73.7 micrograms/L) and gastrointestinal tumor (128.7 +/- 56.4 micrograms/L) (P < 0.01 or 0.05). Serum TGF beta 1 level was elevated in 34 of 47 (72.3%) PHC patients, including 5 of 7 (91.4%) small (< 5 cm) PHC patients. The sensitivity and specificity of diagnosis of TGF beta 1 in PHC were 72.3% and 77.9%, respectively. The diagnostic positivity was 78.5% in AFP-negative PHC patients. The combined assay of serum TGF beta 1 and AFP could further raise the detection rate of PHC up to 93.6%. Above results suggest that serum TGF beta 1 might be a candidate for a novel tumor marker for diagnosis and monitoring of PHC.

Biomarkers, Tumor↗

PubMed1997

[Effects of low-molecular-weight heparin on proliferative glomerulonephritis].

To investigate the effects of LMWH on proliferative nephritis, we randomized 41 patients who had obvious mesangial cell proliferation testified by renal biopsy into 2 groups according to age, course, clinical manifestations and the pathological lesions. The patients in the control group were given steroid, cyclophosphamide and bennazipril, and the patients in the treated group LMWH (fraxiparin) with the dosage of 60 anti Xa IU.kg-1.day-1 besides the medicine used in the control group. We observed a significant decrease in proteinuria and increase in serum albumin in the treated group compared with those in the control group after 4 weeks of treatment (P < 0.05). The improvement of creatinine clearance in the treated group was significant after 8 and 12 weeks treatment compared with that in the control group (P < 0.05). Our data indicated that LMWH can decrease the proteinuria in the patients who have intraglomerular coagulation and proliferative nephritis with various degrees of sclerosis, and it is helpful to relieve nephrotic syndrome. Because the less risk of hemorrhage, LMWH can be used for long-term treatment to prevent glomerulosclerosis and the process of renal function loss without special mornitoring.

Adolescent↗

PubMed1997

[The expression of c-fos gene in cultured bovine trabecular cells induced by epidermal growth factor].

OBJECTIVE: To investigate the effect of epidermal growth factor (EGF) on cultured trabecular cells. METHODS: Molecular hybridization technique was used to investigate the effect of EGF on c-fos expression and its induction of bovine trabecular cells in vitro, and 3H-TdR incorporation method was applied to study the synthesis of DNA. RESULTS: EGF enhanced the incorporation of 3H-TdR into trabecular cells at concentrations ranging from 20-150 ng/ml (P < 0.001). Compared with control, the expression of c-fos appeared at 0.5 hour and 1 hour after stimulation, and did not exist till 2 hr. The level of c-fos expression in cells relied on the concentration of EGF. CONCLUSION: Our results suggest that EGF stimulate trabecular cell proliferation at least in part by the regulation of the c-fos gene and its nuclear protein.

Animals↗

PubMed1997

[Evaluation of emergency surgery in gestational trophoblastic tumours].

We retrospectively analyzed 27 cases of gestational trophoblastic neoplasia treated by emergency surgery from 1985-1996 at PUMC hospital. Seventeen cases were diagnosed of choriocarcinoma and 10 were invasive mole. Sixteen out of 27 patients were subjected to hysterectomy because of uterine perforation or severe uterine bleeding; 4 cases received unilateral oophorectomy because of torsion of theca lutein cyst. Emergency open surgery and excision of the metastatic brain tumour were undertaken in 3 patients with elevated intracranial pressure caused by brain edema and haemorrhage; 2 patients showed lifethreatening haemorrhage from vaginal metastatic tumour and were managed by operative intervention. Partial jejunectomy was performed in 2 patients due to rupture of jejunal metastatic mass. Of these 27 cases, 17 hadn't been treated with chemical reagents and 6 cases had received one course of chemotherapy before surgical procedures. After multiple courses of combined chemotherapy postoperatively, 23 patients had achieved complete remission. It is concluded that surgical intervention plays an important role in patients with trophoblastic disease when emergency situations (e.g. life-threatening haemorrhages) occur; early diagnosis and prompt initiation of chemotherapy might have rendered surgery unnecessary.

Adult↗

PubMed1997

[Measures for decreasing the early mortality after valvular replacement cardiovascular surgery].

To probe the effective measure for decreasing the early mortality after artificial valvular replacement. We analyzed the cause of death among 1215 patients receiving artificial valvular replacement who were admitted in our intensive care unit during 1990-1995. All 44 deaths were serious-illed patients with preoperative cardiac functions of 3-4 degree. The factors affecting surgical survival rate include: enhancement of patient's cardiac function before operation and prevention of cardiac arrhythmia; a clear operational view and myocardial protection, especially for reoperative patients; application of membrane oxygenator; treatment of LCOS without delay, including intraveously administered agents and IABP used promptly when necessary; prevention and treatment of postoperative cardiac arrhythmia; strict, intensive care and synthesized treatment.

Adolescent↗

PubMed1997

[Regeneration of functionally active rat brain muscarinic receptor in vitro after inhibition with methylmercury chloride].

The effect of methylmercury on muscarinic receptors and the regeneration of functionally active muscarinic receptor in vitro by antagonists were investigated. The result showed that methylmercury chloride (MMC) inhibited the binding of [3H] QNB to muscarinic receptor of rat brain-lysed synaptosomes, with IC50 values of 4.18 mmol/L. Regeneration of functionally active rat brain muscarinic receptors after inhibition with methylmercury was achieved by 2,3-dimercapto-1-propanesulfonc acid, Na salt (DMPS) dithiothreitol (DTT), glutathione (GSH) and Cysteine. Blocking the sulfhydryl groups is suggested to be the molecular mechanism of inhibition of brain muscarinic receptors by methylmercury. Our results provide evidence that thiols chelate out mercuric cations that tightly bound to sulfhydryl groups in muscarinic receptor binding sites and regenerate [3H] QNB binding activity.

Animals↗

PubMed1997

[Effect of different hypoxic duration on changes of pulmonary circulation].

In order to assess the relationship between the hypoxic duration and pulmonary hypertension, we investigated the pulmonary hemodynamics and right ventricular hypertrophy and pulmonary vascular structure changes in rats with hypoxic exposure for 1 day to 3 weeks. After hypoxic treatment, the pulmonary artery pressure of rats increased in 3 days, and it was up to peak at 2 weeks later. The weight of right ventricle of rats significantly increased after 1 week. The endothelium of pulmonary vascular of rats became swollen in 3 days, and then increased in extracellular matrix deposition. Vessel wall thickening was found in 1 week hypoxic rats, and it was very significant in 3 week hypoxic rats. The results suggest that the duration of hypoxic treatment is related to the change of pulmonary circulation in 3 weeks in rats.

Animals↗

PubMed1997

[Optimization of quenching system for determination of emodin and chrysophanol by chemiluminescence method].

Determination of the valid components in traditional Chinese medicine is one of the key steps for its identification, and the development of accurate and simple methods is necessary for the present analysis work of medicines. In this paper, the experimental conditions were optimized and procedures chosen for determination of emodin and chrysophanol by lunminol-H2O2-Cr3+ chemiluminescence quenching system. The dynamic range for determination of emodin was 10(-4)-10(-8) g/ml (r = 0.9965), with a detection limit of 1.57 x 10(-9) g/ml. The RSD and recovery for determination of 10(-7) g/ml of emodin (n = 6) were 0.4% and 92.8% +/- 0.5%, respectively. Satisfactory results were also obtained when the method was used to determine chrysophanol. This method was used, after separation by thin layer chromatography, to determine emodin and chrysophanol in several traditional Chinese patent medicines, and the results were in good agreement with those obtained by the standard colorimetric method.

Anthraquinones↗

PubMed1997

[Circadian rhythm of PGE2 level in plasma and condylar cartilage of young growing rats].

This paper reports the circadian rhythm of PEG2 level in plasma and condylar cartilage of young frowing rats. The samples were measured at 0:00, 4:00, 8:00, 12:00, 16:00, and 20:00 respectively. The count of PGE2 were determined by RIA and analysed with simple Cosinor and coordination. The results revealed: (1) The levels of PGE2 in plasma and condylar cartilage of young growing rats fluctuated in strong circadian rhythm; (2) The rhythm of PGE2 in plasma between 16:00 and 24:00 was significantly different from that between 4:00 and 12:00, so for analysing PGE2 level in plasma, one should proper sampling time or adjust it to circadian rhythm; (3) The circadian rhythm of PGE2 in condylar cartilage could provide important reference for reatments in dentistry and orthopaedics.

Animals↗

PubMed1997

[Delayed damage of ionizing radiation on the inner ear].

To investigate the feature and mechanism of delayed effect of ionizing radiation on the inner ear, the function and structure of the inner ear of the guinea pigs were observed during 8 month's period after exposure to fractional doses of gamma radiation (2 Gy per day) with a total dose of 60 Gy. Morphological study was performed using light microscopy, transmission and scanning electron microscopy while the function was measured with electrocochleography (ECochG) and electronystagmography (ENG). The results showed that the mean CAP response threshold was 35.67 +/- 6.78 dB before radiation, and 41.17 +/- 7.76 dB, 47.00 +/- 8.82 dB and 71.00 +/- 7.63 dB at 1st day, 3rd month and 8th months after completion of treatment, respectively. No significant change was demonstrated in the auditory responses at the 1st day of radiation (P > 0.05), but there was obvious hearing loss at 3rd and 8th month (P < 0.01). The nystagmus duration induced by ice water (ENG) was 40.00 +/- 5.44 seconds before radiation, 22.71 +/- 7.93 seconds at 8th month after radiation (P < 0.01). Histologic examination at 8th month after radiation revealed atrophy and degeneration of stria vascularis, a reduced number of capillaries, degeneration of endotheliocyte in vessels, outer hair cell and supporting cell of Corti's organ. The percentage of damaged hair cells in basal turn of the cochlea was significantly higher than those of the upper turn. Degeneration of vestibular hair cell was found. It is suggested that radiation from routine radiotherapy doses may result in a delayed impairment of the inner ear. The main mechanism of the radiation damage may be interference of oxygen supply and metabolism of the inner ear by radiation vascular lesion.

Animals↗

PubMed1997

[Anticarcinogenic effect and hormonal effect of Cordyceps militaris Link].

Cordyceps militaris (CML) has been found good for inhibiting the growth of tumor, prolonging the survival period of mice implanted with S180, inhibiting the growth and metastasis of Lewis pneumonic cancer in the implanted mice, increasing the plasm content of cortisol and testosterone in normal rats, and elevating the weight of sexual organs in normal and castrated rats. CML exerts a malehormone-like effect.

Animals↗

PubMed1997

Suppression of malignant phenotype of a transformed mouse mammary epithelial cell line (11A1) by tumor suppressor gene RB.

A malignant transformed mammary epithelial cell line (11A1) was transfected with liposome encapsulated eukaryotic expression plasmid pCMV-neo-RB, yielding 4 constant clones which have obvious phenotypic reversion changes, and named 11A1-R1-R4 respectively. Further experiments showed that the 11A1-R1 behaved like normal epithelial cells in both morphological and biological characteristics, with decreased clonogenicity in solid argar medium as well as decreased tumorigenicity. Northern blot hybridization showed increased expression of RB gene and decreased expression of c-myc gene in 11A1-R1, 11A1-R2 cells compared to 11A1 cells. This was an ideal phenotypic reversion model for epithelial transformed cell line and demonstrated that the RB gene can reexpress and suppress malignant phenotype in RB inactive cells.

Animals↗

PubMed1997

[Primary study on the use of ovariectomized rabbits for establishment of osteoporosis model].

Purebred New Zealand female rabbits were used in this study for demonstrating the feasibility of establishing rabbit's primary osteoporosis model. Bilateral ovariectomies were performed. Five to eight months after operation, we observed the BMD, weight, hair colour and living condition of the model. After killing the rabbits, we made biomechanical detection and pathologic histomorphometry using the bones. The weight of bone ash, the content of calcium and phosphorus, and the weight of metra were determined. The results showed that BMD, bone bending stress, weight of bone ash, content of calcium and phosphorus in ash, and weight of metra all decreased (P < 0.05); the number of trabecula decreased and the bone cortex became thinner. All these parameters evidenced the primary founding of rabbit's osteoporosis model. This research provides a basis for studying the pathogenesis of primary osteoporosis and evaluating the efficacy of pharmacotherapy.

Animals↗

PubMed1997

[Oral candidiasis in Sjögren's syndrome: prevalence, clinical features and treatment].

The clinical feature of 20 cases with oral candidiasis in Sjögren's syndrome (SS) were reported, and the treatment effect by topical nystatin smearing, 2% sodium bicarbonate solution rinsing, and transfer factor injecting for about 2 months were analysed. The results showed that the diagnostic criterion of oral candidiasis in SS included two aspects: the SS changes confirmed by labial gland biopsy and candidal hyphae and spores found in a smear. The results indicated that the comprehensive treatments were proved to be effective for oral candidiasis in SS.

Adolescent↗

PubMed1997

[cDNA cloning, sequencing and expression of recombinant human prorelaxin].

In order to accelerate the development of biological recombinant human prorelaxin in our country, direct cloning of human prorelaxin gene from freshly prepared corpus luteum of Chinese woman by RT-PCR method was conducted. Isolated prorelaxin gene contains B, A chains and connective peptide. The amplified products were cloned and confirmed by DNA sequencing using Sanger Dideoxy method. It was subcloned into LKB2, a prokaryotic expression vector offering promoter LacI control, and highly expressed in E. coli. The results suggest that the PCR amplified DNA fragment shared identical sequence with known prorelaxin gene reported abroad. The SDS-PAGE analysis revealed that the expressed protein accounted for about 30% of the total cell protein, its MW was approximately 20 kD and conformed soluble protein.

Cloning, Molecular↗