Biomedical subjects

G Liu

Publications and source records attributed to G Liu.

At least 379 records · Page 21Linked to original sources

PubMed1998

[Effects of surface roughness of two restorative materials on early Streptococcus sanguis adhesion in vitro].

This was an in vitro study aimed at the surface roughness of two kinds of commonly used restorative materials resin and alloy necessary to affect the adhesive behavior of Streptococcus sanguis(S. s) on them after 24 h. The surface roughness(SR) of each tested sample was evaluated with a profilometer quantitatively and observed with scanning electron microscope (SEM) morphologically. Then the adhesive microbial amount was determined by the clone forming unit counting method, and adhesion morphology was analyzed with SEM. The result showed a positive linear relation between the adhesion amount of S. s and the SR. The relative coefficients were rresin = 0.46(P < 0.01) and ralloy = 0.25(P < 0.01) respectively. These suggest the SR of the restorative material is important for the early adhesion of oral microbes in vitro. Therefore, before the prothesis is inserted in the patient's oral cavity, its surface should be polished as smoothly as possible so that the bacterial adhesive amount on its surface can be decreased, and hence the patient may keep in good oral health and have a prolonged use of the prothesis.

Bacterial Adhesion↗

PubMed1998

[Determination of airway resistance with the interruption technique in 300 normal adolescents].

The airway resistance (Raw) was determined with interruption technique in 300 normal adolescents aged 12 to 19 years on the RM-6000 polygraph system. FVC, V75, V50, V25 were also measured. The regression equations of expiratory and inspiratory resistances were built with multiple stepwise regression analysis on the IBM-PC/XT computer with age, height and FVC as independent variables. The results showed that both expiratory and inspiratory resistances decreased with age and negatively correlated with height and FVC, but FVC, V75, V50, V25 increased with age. These reflected that Raw declined with the growth and development of the lung and airway proportionally. This fact is correspondent with some international investigations. The rules and regression equations of Raw variation during the growth of adolescents for Chinese presented in this paper can be put to use in public health and clinical work.

Adolescent↗

PubMed1998

An observation on the mimic ecology of the oncomelania hupensis in three-Gorge-reservoir areas.

According to the modulation of three-gorge-reservoir water level, the two observation spots were established at Gaoyang Town and Jianshe Village in Xingshan County of Hubei Province in order to observe the survival and reproduction of the oncomelania under different ecological conditions. Our one-year observation revealed that most settled oncomelania died between June and August in the year and only a few of them survived the winter. The oncomelania hupensis's survival rate in group I, II, III settled in Gaoyang Town was 10%, 1%, 0%, respectively, and the oncomelania Sichuan's 12.5%, 22.5%, 13.5%. The rates obtained from spots in Jianshe Village is 0%, 2%, 0% and 9.5%, 19%, 3%, respectively. The survival rate of oncomelania Sichuan was higher than that of the oncomelania hupensis in the two spots. After draining the feeding pools, the soil samples were harvested and used for egg-hatching. The numbers of eggs that hatched in group I, II in Gaoyang were 1 and 2, respectively. The young oncomelania were found in each spot pool after the drainage, suggesting that the local condition is favorable to the oncomelania and the mating season of each group oncomelania is from April to August with the most active mating time being from May to June.

Animals↗

PubMed1998

[Diagnostic value of p53 protein examination in lung cancer through preoperative fibro-optic bronchoscope brushing and biospy].

OBJECTIVE: To study the expression of p53 protein in lung cancer and benign pulmonary diseases through preoperative fibro-optic bronchoscope brushing and biospy as an approach to early diagnosis of lung cancer and to explore correlation between the expression of the gene product and metastatic involvement of hilar or mediastial lymph nodes. METHODS: Using a monoclonal antibody against p53, the expression of p53 protein was determined by immunocyto-histochemical techniques. RESULTS: Positive staining of p53 protein of cells obtained form bronchoscopic brushing and biospy was 33.3% (12/36) and 47.2% (17/36) respectively in lung cancer patients. There was 61.1% (22/36) positive staining of cells harvested by brushing plus biospy in lung cancer. No correlation between p53 protein expression and cell differentiation, histologic type or pTNM staging. No p53 expression was observed in benign pulmonary diseases. CONCLUSION: p53 protein expression in cells collected from bronchoscopic brushing and biopsy may be useful in the diagnosis of lung cancer.

Adenocarcinoma↗

PubMed1998

[Observation and analysis on metabolism of serum calcium and phosphorus in patients with pregnancy-induced hypertension].

37 patients with obvious pregnancy-induced hypertension, 56 normal pregnant women and 40 nonpregnant women in the same age groups were tested on their serum calcium(Ca), phosphorus(P) alkaline phosphatase(AKP), parathyroid hormone(PHT) and calcitonin(CT). Results indicated that the respective means of serum Ca and CT were statistically lower (P < 0.05), while AKP and PTH were higher (P < 0.01) than that of normal pregnant women. It was also confirmed that Ca metabolism of patients with pregnancy-induced hypertension was obviously abnormal. In addition, pathogenesis of pregnancy-induced hypertension was also discussed.

Adult↗

PubMed1998

[A survey of main allergic pollen in pollinosis in district of Wuhan].

In order to investigate the variety of the main allergic pollen of pollinosis in district of Wuhan city, A survey of airborne pollen was conducted with the nationally acknowledged standards and methods. While carrying out the survey, 200 pollinosis patients queried the main allergic pollen by their skin sensitivity test to identify the pollinosis occurrence time. The result showed that the airborne allergic pollen peak time each year occurs in two seasons: in spring from March to May and in autumn from August to October, in accord with the peak time of pollinosis in spring from April to June and in autumn from September to November. It revealed that the main resulting pollen in Wuhan during the spring-autumn, providing an important foundation for diagnose and treatment of pollinosis in Wuhan city.

Adult↗

PubMed1998

[A prospective investigation on interferon treatment of chronic hepatitis B].

Mismatched polymerase chain reaction and restriction fragment length polymorphism assay together with neutralization bioassay were performed in order to elucidate the influence of pre core mutation of HBV genome and neutralizing anti-INF on the therapeutic efficacy of IFN-2b. In 29 patients treated with IFN alpha-2b, HBV DNA pre core mutation were detected in 15 patients (15/29, 51.7%), HBV DNA in 7 of these 15 patients (7/15, 46.6%) turned to negative, all of whom were recurrent one year follow up. In the other 14 patients without pre core mutation, 7 patients (7/14, 50%) became serum HBV DNA negative, none of whom were recurrent. HBV DNA was undetectable in 4 of the 15 patients (4/15, 26.7%) with neutralizing antibody. In contrast, HBV DNA became undetectable in 10 of the 12 patients (10/12, 83.3%) without neutralizing antibody (P < 0.05).

Adult↗

PubMed1998

[Significance of detecting E-selectin of serum and pleural effusion in differentiating benign and malignant diseases].

OBJECTIVE: To evaluate the significance of detecting E-selectin of serum and pleural effusion in differentiating benign and malignant diseases. METHOD: E-selectin of serum and pleural effusion in 23 patients with tuberculous pleurisy and 21 patients with lung cancer involving pleura was detected by ELISA method. RESULT: E-selectin of serum(44 +/- 5 micrograms/L) and pleural effusion (24 +/- 3 micrograms/L) in patients with tuberculous pleurisy was much higher than that of serum (27 +/- 4 micrograms/L) and pleural effusion (11 +/- 3 micrograms/L) in lung cancer patients (P < 0.01). In addition, E-selection of serum in patients with tuberculous pleurisy was also much higher than that of pleural effusion (P < 0.01). And there was no correlation between E-selectin of serum and that of pleural effusion in patients with tuberculous pleurisy (r = 0.16, P > 0.05). CONCLUSION: E-selectin of serum and pleural effusion in patients with tuberculous pleurisy is produced from different sources. And E-selectin in patients with tuberculous pleurisy is much higher than those with lung cancer. Thence detecting E-selectin of serum and pleural effusion might be helpful for differentiating benign and malignant diseases.

Adult↗

PubMed1998

Effect of hypoxia on motion sickness induced by optokinetic stimulation.

The purpose of this experiment was to study the effect of hypoxia on motion sickness (MS) induced by optokinetic stimulation and to observe its character and principle. Twenty healthy male subjects aged 18-25 years received optokinetic stimulus (OS) and hypoxic-optokinetic stimulus (HOS) according to the "Latin Square" arrangement and "Self-control" methods. Motion sickness symptoms (MSS) and optokinetic horizontal nystagmus (OKHN) were recorded and analysed. The results indicated: (1) MS average score for HOS was higher than that for OS (P<0.001); (2) Slow phase velocity(SPV) of OKHN in HOS was lower than that in OS (P<0.001). The results clearly showed that moderate hypoxia could deteriorate the MS induced by OS. It provided a method for the screening of MS sensitivity.

Adolescent↗

PubMed1998

[Investigation of plasma and urine concentration of Cholecystokinin and Somatostatin in pilots and ground crew].

Concentration of Cholecystokinin(CCK) and Somatostantin(SS) in Plasma, 24 h urine and morning urine were observed in 57 pilots (22-45 years, mean 27.9) and 60 ground crew (23-47 years, mean 30.7). The results showed that CCK level in plasma, 24 h urine and morning urine (20.14 +/- 4.15, 10.08 +/- 2.29 and 11.29 +/- 2.18 pmol/L respectively) in pilots were significantly lower than those in ground crew (22.89 +/- 3.76, 7.04 +/- 1.03, 8.10 +/- 1.94 pmol/ L respectively) and those of SS were distinctly higher than in ground crew (12.38 +/- 2.34, 6.75 +/- 1.18, 7.41 +/- 1.27pmol/L respectively). Concentration of CCK and SS in plasma were positively related to those in 24 h urine and morning urine both in pilots and ground crew. It suggests that these changes might play potential role in the pathogenesis of some diseases of digestive system in pilots.

Adult↗

PubMed1998

[Energy metabolism of men in full pressure suit with additional pressure].

The energy metabolism of men in full pressure suit with additional pressure and without additional pressure were measured during rest and exercise. Results show that the rates of energy metabolism of men in full pressure suit with additional 28 kPa pressure and without additional pressure increased as the exercise load increased. The rates of energy metabolism of men in full pressure suit with additional 28kPa pressure had no significant difference during rest and 0.9W exercise, but significantly increased during 8.5 W exercise, as compared with that without additional pressure. It suggested that full pressure suit with 28 kPa did not affect human energy metabolism during rest, but affected during exercise.

Aerospace Medicine↗

PubMed1998

[Preliminary experiment on selection of oral hygienic cleanser].

The effectiveness of three commercial chewing gums ("Hua Aikang","Cao Shanhu" and "Poli") and brushing with toothpaste on the elimination of dental plaque was observed in 31 healthy males (aged 19-25 years). Before and after chewing or brushing, evaluation of oral taste and examination of plaque were performed. The result showed that the oral taste after chewing, "hua aikang" was the best, then "po li" and "cao shanhu"; plaque indexes were substantially reduced by all four kinds of treatment (P < 0.001) as compared with the pretest values, however "hua aikang" demonstrated a better effectiveness (P < 0.001). It also indicates that plaque index is an important index revealing the hygiene status.

Adult↗

PubMed1998

[Effects of hypoxia and qigong on urine malondialdehyde, superoxide dismutase and circulating endothelial cell in humans during simulated weightlessness].

Changes of lipid hyperoxidation and amount of circulating endothelial cells under simulated weightlessness and factors that may influence these changes were observed in 3 groups of subjects (5 in each group) exposed to 17d - 6 degrees head down bed rest (HDBR), HD-BR+ hypoxia and HDBR + qigong respectively. The results showed: (1) simple HDBR promotes antioxidation activity and attenuates hyperoxidation of lipids, and hypoxia and have some influence on the former but not on the latter; (2) circulating endothelial cells decreased significantly after simple HDBR for 7 d but recovered to normal when HDBR continued for 17 d. Hypoxia showed no influence on this effect while Qigong alleviated it significantly. It suggests that (1)both hypoxia and Qigong have some influence on the promotion of antioxidation activity but have no influence on the production of oxygen free radicals. (2) Qigong shows some antagonistic effect against the attenuation of circulating endothelial cells by HDBR.

Bed Rest↗

PubMed1998

[Observation on changes of heart rate and energy metabolic rate and their regression under upper and lower limb exercise].

Energy metabolic rate and heart rate were observed in 8 healthy young men during exercise on a bicycle ergometer. The results showed that there is a linear relationship between heart rate and metabolic rate during both upper and lower exercise, only that the metabolic rate is higher during upper limb exercise than during lower limb exercise under the same work load. It suggests that work efficiency may be influenced by mode of exercise.

Adolescent↗

PubMed1998

A biomechanical analysis of unilateral hooked-sulcated external fixator on osteomined tibia.

Four tibiae removed from 30-40 years males, who died of accidents in less than 12 hours, were osteomized at medium part. Then these tibiae were fixed by an unilateral hooked-sulcated external fixator (UHSEF), and the bone-fixator system was used as a model of external fixation of tibial fracture. The axial compression, distraction, torsion, antero-posterior and lateral bending rigidity and the strain of the pins were determined in this system. Based on the results, we found that compared with the configuration of four paralleled pins, the rigidity of the fan-like configuration didn't decrease significantly if the angle between lateral and medium pins was less than 45 degrees. But the reverse was true when the frame separation increased from 5 to 8 cm. What' more, the pin strain decreased if the rigidity of the system was improved. These data provided a theoretical basis of biomechanics for the improvement of UHSEF.

Adult↗

PubMed1998

Cloning and characterization of a metal responsive element-containing fragment from the Wilson disease gene locus by junction trapping.

All mammalian metallothionein genes studied to date have several metal responsive elements (MRE) with consensus sequences of TGCRCNC (R, purine) in their regulatory region. MRE-like sequences were also found in many other metal-related genes. To see whether there is also such a sequence at the genetic locus (13q14.3) of Wilson disease, which is a genetic disorder of copper metabolism, junction-trapping method based on the MRE sequence was used. A fragment containing MRE and MRE-like sequences from YAC 27D8 at the WND locus was successfully cloned and mapped back to the YAC by PCR. Presence of such a sequence in the copper transporter gene at the WD locus might imply that it has a possible interesting role in the regulation of WD gene expression.

Adenosine Triphosphatases↗

PubMed1998

[Effects of some mexiletine derivatives on alpha 1-adrenoceptors].

Using [3H]-WB 4101 binding assay in rat cerebral cortex membranes, effects of 18 mexiletine derivatives on alpha 1-adrenoceptors were studied in order to find new antihypertensive alpha 1 receptor blocking agents. The results showed that 6 of them showed significant affinities to alpha 1-adrenoceptors in rat cerebral cortex membranes. Some structure-activity relationship were found, among them only the compounds with chiral carbon showed high affinity to alpha 1-adrenoceptor. The affinity of compound M-85001 (pKi = 6.51) was shown to be higher than that of tolazoline. In the rat anococcygeal muscle, compound M-85001 competitively antagonized phenylephrine-induced contraction with pA2 value of 6.86 which is similar to its pKi value in the binding assay. These findings may be of significance in the search for novel class of alpha 1 receptor antagonists.

Adrenergic alpha-1 Receptor Antagonists↗

PubMed1998

[Protective effects of schisanhenol against oxygen free radical induced injury of rat cerebral mitochondria and synaptosomes].

The cerebral tissue injury induced by ischemia and reperfusion or trauma has been considered to be due to over production of oxygen free radicals (OFRs). The aim of this study was to evaluate the effects of schisanhenol (Sal) on Fe(2+)-cysteine (Cys) induced injury of rat cerebral mitochondria and synaptosomes in vitro. Incubation of cerebral mitochondria or synaptosomes with Fe(2+)-Cys at 37 degrees C resulted in an increase of malondialdehyde (MDA) formation and decrease of ATPase activity. Sal(10(-4) mol.L-1) completely inhibited Fe(2+)-Cys induced increase of MDA formation of mitochondria and synaptosomes as well as the loss of ATPase activity of mitochondria. The swelling of mitochondria and reduction of membrane fluidity of mitochondria and synaptosomes induced by Fe(2+)-Cys were also prevented by Sal. Sal(10(-5) mol.L-1) was shown to significantly inhibit the decrease of synaptosomal GSH content induced by H2O2. The electron micrographs also showed that Sal markedly reduced the pathological damage of mitochondria and synaptosomes induced by Fe(2+)-Cys. The results suggest that Sal has protective action against Fe(2+)-Cys induced injury of rat cerebral mitochondria and synaptosomes.

Adenosine Triphosphatases↗