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Biomedical subjects

C X Wang

Publications and source records attributed to C X Wang.

At least 73 records · Page 4Linked to original sources
PubMed1995

A study of the mechanism of butachlor-associated gastric neoplasms in Sprague-Dawley rats.

Long term administration of butachlor to Sprague-Dawley rats in a previous bioassay, resulted in the induction of gastric neoplasms which occurred only in the highest dose group (3000 ppm in the diet), primarily in females and specifically in the fundic region. The tumors were a composite of highly undifferentiated enterochromaffin-like (ECL) cells and mucus producing cells with morphologic characteristics unlike those previously described in the rat stomach. Mucosal atrophy of marked intensity was a consistent feature of the gastric mucosa in animals from the highest dose group. An additional long term study was conducted in female Sprague-Dawley rats at dietary levels of 0, 100, 1000 and 3000 ppm to explore the mechanism(s) involved in the formation of these neoplasms. Cell proliferation was evaluated in both fundic and pyloric regions of the stomachs of rats at multiple time periods from 14 days to 26 months. Mucosal thickness was determined in the fundic region at the same time intervals as were used for cell proliferation studies. Gastric pH and gastric acid production were measured after approximately 21 months of exposure. Serum gastrin levels were analyzed at 14, 60, and 120 days and at 6, 18 and 20 months. Cholecystokinin (CCK)/gastrin receptor binding studies were conducted on samples of four tumors and pooled fundic mucosa from five animals in the control group. Cell proliferation was increased in both the neck and base regions of the fundic mucosa at nearly all time points measured from 14 days to 26 months. The magnitude of the changes in the base region were substantially greater than those in the neck region. Fundic mucosal thickness was decreased beginning at the 30-day time point and continued at all intervals, being less than one half that of controls at 20 and 26 months. Gastric pH in rats from the highest dose was elevated to nearly twice control levels at 21 months. Gastric acid secretion was dramatically decreased in animals from the 3000 ppm group and was moderately decreased in the 1000 ppm group at 21 months. Hypergastrinemia was observed at the 3000 ppm level only, beginning at 120 days with progression to extremely high levels by 18 months. CCK/gastrin receptor binding was demonstrated in all tumors studied, at levels comparable to or higher than that of the pooled control sample. All changes involved only the fundic region, the site of tumor formation. Tumors occurred only in animals from the 3000 ppm level, the only level at which hypergastrinemia occurred.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetanilides↗
PubMed1995

[Effect of qigong on heart-qi deficiency and blood stasis type of hypertension and its mechanism].

Comparative study was performed on the Heart-Qi Deficiency and Blood Stasis type (HQDBS) of hypertensive patients treated with Qigong. The results showed that the clinical symptoms alleviated, cardiac morphology and function, hemorheology and erythrocyte deformity were improved. After one year of practicing Qigong, plasma histofibrinogen activation inhibitor (PAI) and VIII factor related antigen (VIII R: Ag) levels decreased, while plasma tissue fibrinolytic activator (t-PA) and anti-thrombogen III (AT-III) levels increased. Capillary blood velocity of nailfold microcirculation raised from 0.2940 +/- 0.0206 mm/s to 0.3045 +/- 0.0236 mm/s, the diameter and length of afferent limb tended to increase. The above data indicated that Qigong could benefit HQDBS. This might be the mechanism by which HQDBS type of hypertension was treated.

Aged↗
PubMed1994

Dose response of promotion by butylated hydroxyanisole in chemically initiated tumours of the rat forestomach.

The antioxidant food preservative butylated hydroxyanisole (BHA) was tested in an initiation-promotion protocol in which male F344 rats (6 wk old), 27 per group, were gavaged with a single dose of 200 mg N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)/kg. After 3 wk on control diet, test diets containing 0, 60, 300, 1000, 3000, 6000 or 12,000 ppm BHA were fed until termination of the experiment at approximately 110 wk, at which time most animals had died with stomach tumours. MNNG caused a high incidence of tumours in the glandular stomach and forestomach of all groups. Administration of 12,000 and 6000 ppm BHA, but not 3000 ppm or lower doses, caused statistically significant increases in the time-related incidence of MNNG-induced forestomach tumours as analyzed by life table analysis. BHA had no effect on the incidence of tumours in the glandular stomach or oesophagus. Tumour incidences in other organs were not related to BHA dose. No increase in hyperplasia in the oesophagus was evident in the high-dose BHA-treated animals compared with the MNNG-only group. This study provides corroboration that BHA affects only forestomach tumorigenesis and that the dose for enhancement of tumorigenesis is at least 1500-fold greater than human exposure.

Animals↗
PubMed1994

Analysis of spermatozoa from the proximal vas deferens of vasectomized men.

This study assessed the condition of spermatozoa from the proximal vas deferens of men after vasectomy. The fluids of both proximal vas deferens were collected from 67 vasectomized men by cannulating the vas deferens at the time of vasectomy reversal. Selected sperm parameters were analysed after incubation of the spermatozoa for 30 min at 37 degrees C. Sperm concentration in the proximal vas from vasectomized men (16,312 +/- 21,496 million per ml, geometric mean: 7948 +/- 398 million per ml) was significantly higher than that of fertile men and was maintained at a constant level independent of the duration of vas obstruction. The means of sperm motility (36.2 +/- 26.2%), spermatozoa with normal morphology (50.7 +/- 21.7%), sperm viability (53.0 +/- 25.3%) and hypo-osmotic swelling test (HOS-test, 53.9 +/- 21.7%) were statistically lower than the respective values for normal fertile men. There was no significant correlation between the duration of vas obstruction and the above semen parameters. In 46.4% of vas fluids all spermatozoa were immotile and this condition was more common after 3 years of vasectomy. Immotile spermatozoa in the proximal vas fluids at the time of vasectomy reversal may be an important factor for predicting semen quality and fertilizing ability after vasovasostomy. There were no significant differences in the results of sperm-cervical mucus penetration test (CMPT) between spermatozoa from vasectomized and fertile men. Antisperm antibodies on the surface of spermatozoa from the vas of vasectomized men were determined by the immunobead test (IBT; 78.6% for IgG, 32.1% for IgA) and sperm cervical mucus contact test (SCMC, 36.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Combined non-operative intervention for retained bile duct stones].

Basket lithotriptor, piezoelectric shock wave lithotripsy, electrohydraulic shock wave lithotripsy, and endoscopic papillosphincterotomy were used to manage respectively 10, 15, 14, and 15 patients with retained intra and extrahepatic bile duct stones that could not be removed with a Dormia basket. In these four group patients the stones ranged from 5 to 25 mm in diameter. A residual stone was fragmented with a basket lithotriptor if its diameter exceeded that of the T tube tract. Shock-wave was used when mechanical lithotripsy was unsuccessful. Endoscopic papillosphincterotomy was carried out in patients with stenosis of the sphincter, or impacted stone at the Ampulla of Vater. Combined biliary lavage, Dormia basket, and choledochoscopy after lithotripsy accelerated clearance of fragments. In these four groups, stone-free rates and reoperation rates were 90, 46.7, 85.7, and 100 percent and 10, 6.6, 14.3, and 0 percent respectively. There were no serious complications.

Adolescent↗
PubMed1994

Paternity identification in twins with different fathers.

If a female has sexual intercourse with two males at short intervals within the same ovulatory period, superfecundation may occur. This article reports two cases of paternity identification in twins. The results showed that each twin had come from a different father. Thus, great attention should be paid to such a situation when the twin paternity identification is asked for.

Blood Grouping and Crossmatching↗
PubMed1993

Thermodynamic integration calculations of binding free energy difference for Gly-169 mutation in subtilisin BPN'.

The binding free energy difference for the Gly-169-->Ala-169 (G169A) mutation in subtilism BPN' complexed with a tripeptide substrate analogue is explored using the thermodynamic integration approach. The structure of the mutant enzyme-substrate complex obtained from free energy simulation is in good agreement with experimental X-ray refinement. The near perfect reversibility is obtained in the present work for ensuring the correctness of the free energy calculations. The results of the binding free energy difference are close to similar experimental data.

Amino Acid Sequence↗
PubMed1993

Diethylstilbestrol liver carcinogenicity and modification of DNA in rats.

Administration of diethylstilbestrol to female Sprague-Dawley rats at 10 mg/kg body weight daily by gavage for 1 year induced liver adenomas and carcinomas and pituitary adenomas. Using the 32P-postlabeling assay for DNA alterations, at 24 h after administration of a single dose of 100 mg/kg, modified bases were found.

Adenoma↗
PubMed1993

Congenital absence of vas deferens treated by artificial spermatocele constructed from the tunica vaginalis; report of six cases.

Six patients with congenital absence of the vas deferens were treated by artificial spermatoceles (ASCs) in an attempt to collect sperm for subsequent artificial insemination (AI). The ASC was constructed from a flap of tunica vaginalis from the patient. Sperm were aspirated from the ASC each month; there was wide variation in the concentration of sperm recovered [33.0 +/- 48.2 x 10(6) mL-1 (range 0.1-200)] and motility and normal morphology of the sperm were 19.0 +/- 17.9% and 48.8 +/- 23.4% respectively. Although a total of 14 cycles of AI was performed using the aspirated sperm, pregnancy did not result. Both poor sperm recovery and poor motility contributed to this failure. The condition of the epididymis observed during scrotum examination is reported. It is suggested that in some patients with congenital absence of vas deferens, the paired Wolffian ducts may differ from each other in their development.

Adult↗
PubMed1993

Can the stability of protein mutants be predicted by free energy calculations?

The use of free energy simulation techniques in the study of protein stability is critically evaluated. Results from two simulations of the thermostability mutation Asn218 to Ser218 in Subtilisin are presented. It is shown that components of the free energy change can be highly sensitive to the computational details of the simulation leading to the conclusion that free energy calculations cannot currently be used to reliably predict protein stability. The different factors that undermine the reliability are discussed.

Asparagine↗
PubMed1993

Analysis of spermatozoa from the proximal vas deferens of fertile men.

Fluids from the left and right proximal vas deferens were collected from 105 normal fertile men by cannulating the vas deferens during vasectomy, and sperm parameters analysed. Sperm motility (73.1 +/- 13.3%), normal sperm morphology (75.2 +/- 11.1%), sperm viability (72.7 +/- 18.8%) and the hypo-osmotic swelling test (73.3 +/- 19.2%) were in the normal range, compared with that of ejaculated spermatozoa. However, sperm concentration in the proximal vas deferens (6274.6 +/- 5103.8 x 10(6) ml-1 was higher than that in semen. Sperm concentration in the right vas deferens was significantly higher (P < 0.05) than that in the left and the percentage of spermatozoa showing abnormal cervical mucus penetration was significantly higher (47%) for the left than for the right (18%). There were no anti-sperm antibodies on the surface of spermatozoa from the vas deferens as determined by the sperm cervical mucus contact test and immunobead test. These parameters of spermatozoa from the proximal vas may reflect those of spermatozoa from the human cauda epididymis.

Adult↗
PubMed1993

Motor evoked potentials in a static load model of spinal cord injury in the rat.

Motor evoked potentials (MEPs) are used to evaluate spinal cord injury. In this study, the effect of different grades of static load spinal cord injury on MEPs was examined. Rats (n = 27) were anesthetized, ventilated, and curarized. MEPs were elicited by the stimulation of the right sensorimotor cortex and recorded with a needle electrode placed in the epidural space on the left side at T10. The spinal cord injury was produced by gently placing a weight (20, 35, or 50 g) on the spinal cord at the level of T3. The compression time was 5 minutes. A group of rats in which laminectomies were performed but in which no weight was put on the spinal cord served as a control group. MEPs were recorded before, during, and after the spinal cord lesion was produced. The MEPs in the 0g group were stable. While the spinal cord was compressed, the MEP positive peak latencies increased and the amplitudes decreased and finally disappeared. MEP latencies and amplitudes correlated well with the weight used for spinal cord compression. During spinal cord compression, MEPs vanished, starting from peaks with a longer latency to peaks with a shorter latency. After decompression, the peaks reappeared in a reverse order. This study shows that MEPs are a good parameter for the functional integrity of spinal cord motor pathways in a static load type of injury model.

Animals↗
PubMed1993

[Effect of qigong on plasma coagulation fibrinolysis indices of hypertensive patients with blood stasis].

The levels of plasma tissue-type plasminogen activator (tPA), plasminogen activator inhibitor (PAI), VIII factor related antigen (VIIIR:Ag) and anti-thrombin (AT-III) were determined in 40 hypertensive patients with Blood Stasis. The results indicated that the function of coagulation-fibrinolytic system was disturbed. After one year of practising Qigong, plasma PAI and VIII R:Ag levels were decreased, while plasma tPA and AT-III levels increased. It suggested that Qigong could improve the function of coagulation-fibrinolytic system.

Aged↗
PubMed1993

Submicrostructure and typing of female genital condylomata.

Thirty biopsies from female genital condylomata were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study structural characteristics and typing of condylomata. It was found that cytoplasmic clearing was marked in acuminate condylomata, diffuse interstitial and epithelial proliferation in nodular condylomata (flat condylomata), and invagination of the lesions into the interstitial tissue or glandular ducts in endophytic condylomata. In nodular condylomata, SEM also showed some structural features similar to those of intra-epithelial neoplasia. Microridges on the surface of squamous cells had villiform of granular changes. On the surface of a percentage of squamous or columnar cells, there were holes with a diameter of about 3 to 5 microns. A number of giant cells were seen among other cells. The cervical squamatization zone contained groups of special cells covered with dense microvilli. TEM of nodular condylomata revealed some pictures resembling active proliferation of tumor cells, such as enlarged or irregular nuclei (large N/C ratio), evaginated or invaginated nuclear membranes, condensed chromatin attached to the inner part of the nuclear membrane, transparent nucleoplasm, and frequent nucleosomes and karyokinesis. Virus particles with the morphological characteristics of HPV (naked hexagon-like particles with an average diameter of 45-50 nm) were seen in some nuclei with markedly condensed chromatin. It is suggested that HPV-induced genital condylomata, especially nodular one (flat condylomata), entail a potential progression to malignancy.

Adult↗
PubMed1991

[The beneficial effect of qigong on the ventricular function and microcirculation in deficiency of heart-energy hypertensive patients].

Ultrasonic cardiogram was performed on 120 aged subjects. Experiment showed that the left ventricular function in the hypertensive aged group (n = 80) was lower than that in the aged group (n = 40), while the left ventricular function in the deficiency of heart-energy hypertensive patients (n = 46) was the lowest in the non-deficiency of heart-energy hypertensive patients (n = 34). After practising Qigong for 1 year, the cardiac output (CO) was increased, the total peripheral resistance (TPR) was decreased, ejection fraction (EF) mitral valve diastolic closing velocity and mean velocity of circumferential fiber shortening (mvcf) tended to be increased. The results indicated that Qigong had a regulatory effect on haemodynamic alteration as well as on improvement of left ventricular function. Nailfold microcirculation detection of 120 aged subjects was made. It found that hypertension had an accelerating effect on the disturbance of microcirculation. The incidence of disturbance of microcirculation was 73.91% in the deficiency of heart-energy hypertensive patients, after 1 year Qigong practice, the incidence of disturbance of microcirculation was 39.13% (P less than 0.01). The result suggested that Qigong had an effect to improve the disturbance of microcirculation. The above data indicate that Qigong can benefit heart-energy and regulate the blood channel.

Aged↗
PubMed1991

Free radicals-induced abnormal chondrocytes, matrix and mineralization.A new concept of Kaschin-Beck's disease.

Free radical generating substances, including fulvic acids, mycotoxins, Fe(II), etc attack chondrocytes, causing dedifferentiation. The dedifferentiated cells synthesize and secrete abnormal collagens rich in type I instead of the normal type II. These substances also directly attack collagens in the extracellular matrix. The abnormal collagens make the matrix change from hydroxyapatite crystallization inhibiting to promoting, and give crystals of low crystallinity, high aggregation and small size. This study leads to a new concept of the development of Kaschin-Beck's Disease (KBD).

Animals↗
PubMed1990

Toxicity studies of butylated hydroxyanisole and butylated hydroxytoluene. II. Chronic feeding studies.

The antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were fed in the diet to male F344 rats in two chronic feeding studies. In one study, feeding BHT for 76 wk at concentrations ranging from 100 to 6000 ppm produced no increase in neoplasms at any site. In a second study, feeding 12,000 ppm BHT for 110 wk had no neoplastic effect at any site, whereas feeding BHA at 12,000 ppm resulted in a small increase in squamous cell papillomas of the non-glandular squamous portion of the stomach.

Animals↗