Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 307 records · Page 17Linked to original sources

PubMed1999

[Comparative genomic hybridization analysis of primary gastric carcinomas].

OBJECTIVE: To investigate whether unknown genes are involved in the tumorigenesis of gastric cancer. METHODS: Fourty-three primary gastric carcinomas were analyzed by comparative genomic hybridization(CGH). RESULTS: A gain in chromosome 3p(8/43), 8q(8/43), 20[20(9/43), 20p(7/43), 20q(4/43)], 12q (16/43), and 13q(12/43) was observed while a loss of 19[19(15/43), 19p (13/43)], 17[17(8/43), 17p(10/43)], 16(10/43) and 1p(11/43) was discovered. CONCLUSION: There were characteristic changes in 3p, 8q, 20, 12q, 13q, 19, 17, 16, and 1p in gastric carcinoma, and some unknown genes located in the above regions might be of importance to gastric carcinoma pathogenesis.

Chromosome Aberrations↗

PubMed1999

Detection of small lesions in alveolar bone by digital subtraction radiography.

OBJECTIVE: To evaluate the effectiveness of digital subtraction radiography (DSR) system for diagnosis of small artificial alveolar bone lesions. METHODS: Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of dry human mandibles. Reference and subsequent radiographs were taken before and after lesions were made. The small lesions were detected by conventional radiography and DSR respectively. RESULTS: For 0.2-0.5 mm3 lesions, detection by both DSR and conventional methods was less than 50%. For 0.7 mm3 lesions, the detection by DSR and conventional methods was 57.5% and 38.7%, respectively (P < 0.01). For 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P < 0.01). CONCLUSION: The detectability of small alveolar bone lesions by DSR was superior to that of the conventional method.

Alveolar Bone Loss↗

PubMed1999

[Mitochondrial tRNA(leu(UUR)) gene mutation and the decreased activity of cytochrome C oxidase in preeclampsia].

OBJECTIVE: To study the effect of mitochondrial tRNA(leu(UUR)) gene mutation at nuecleotide 3243 and the activity of cytochrome C oxidase on the pathogenesis of pregnancy induced hypertension(PIH). METHODS: 57 cases of PIH and 60 normal pregnancy women were detected of tRNA(leu(UUR)) nt3243A-->G mutation with the method of polymerase chain reaction (PCR) and restriction fragment length polymorphism. Cytochrome C oxidase activity was measured by the rate of cyanide-sensitive oxidation of reduced cytochrome C using luminosity photographer. RESULTS: Cytochrome C oxidase activity was significantly lower in the PIH group than that of controls. The mitochondrial DNA mutation at position 3243 was not found in any of the cases. CONCLUSION: These results suggested that the decreased activity of cytochrome C oxidase might impair the energy production, leading to the mitochondrial dysfunction and placental dysfunction in PIH patients. Mitochondrial dysfunction may be involved in the pathogenesis of preeclampsia. The particular mutation of mitochondrial DNA may not be the common contributor of PIH.

Adult↗

PubMed1999

[Intrapulmonary expression of tumor necrosis factor alpha mRNA and its significance in rats with acute pancreatitis].

It is thought that tumor necrosis factor (TNF) plays an important role in pathogenesis of acute lung injury or ARDS. So we want to get insight into the relationship between intrapulmonary expression of TNF-alpha gene and lung injury during acute necrotizing pancreatitis (ANP). In our study, acute edematous pancreatitis (AEP) and ANP were induced in rats by caerulein and sodium taurocholate respectively. After acute pancreatitis was induced, serum TNF-alpha was assessed by ELISA assay while endotoxin was assessed by limulus lysate test. Intrapulmonary expression of TNF-alpha mRNA was detected by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Moreover, content of pulmonary lesion was investigated and graded with microscope. It was found that TNF-alpha concentration in blood elevated markedly after acute pancreatitis was induced, especially in ANP group. Results of RT-PCR revealed that no TNF-alpha mRNA could be detected in lung tissue from those rats undergoing sham-operation, but marked expression appeared 1 hour after AEP or ANP was induced. Upregulation of expression of TNF-alpha gene in the early 3 hours was similar in the two groups with pancreatitis, and since then expression of TNF-alpha mRNA in ANP group was stronger than that in AEP group. Serum endotoxin increased significantly 6 hours after ANP was induced, with a higher level at 12 hour. However, there was no marked change of endotoxin level in AEP group and control group. It is noted that intrapulmonary expression of TNF-alpha gene in ANP group reached its peak as soon as serum endotoxin increased markedly. Lung damage in ANP group was more serious than that in AEP group significantly. Score of lung injury correlated well with TNF-alpha concentration in blood and expression of its gene in lung tissue in either AEP group or ANP group, as well as with serum endotoxin in ANP group. So overwhelm expression of some harmful cytokines like TNF-alpha in lung tissue may be the main cause of lung injury during acute necrotizing pancreatitis, and stimulation of endotoxiemia can at least partly explain the upregulation of expression of TNF-alpha gene.

Animals↗

PubMed1999

[Apoptosis and necrosis of neuron after focal ischemia in brain of rats].

This article reports the apoptosis and necrosis of neurons following ischemia-reperfusion in the brain of rats. The focal ischemia model was established by occluding the middle cerebral artery for 2 h and reperfusing for 0.5-48 h. The neuronal changes were investigated by HE staining, TUNEL and agarose gel-electrophoresis. The foci of ischemia were in the preoptic area, striatum and cortex. At 0.5 h of reperfusion, there were quite a few apoptotic neurons in the preoptic ischemic focus, but only a few scattered apoptotic cells were seen in the striatum and cortex. During 3-6 h of reperfusion, the number of apoptotic cells increased and the necrotic cells appeared. The number of apoptotic cells reached a peak at 12-24 h and the in morphology varied, and they were mainly located in the inner boundary of infarct. At 48 h, the apoptotic cells decreased; and the necrotic cells increased. Agarose gel-electrophoresis showed the dense smear and ladder pattern of DNA fragments, the apoptosis and necrosis of neurons coexisted, and apoptosis contributed to the enlargement of the ischemic infarct.

Animals↗

PubMed1999

[Surveillance and diagnosis of laryngeal burn].

OBJECTIVE: To explore early diagnosis and treatment of laryngeal burn, in order to prevent laryngeal obstruction, define the prevention of laryngemphraxis, and elect optimal time of treatment and appropriate treatment. METHODS: A total of 18 patients suffering from laryngeal burn were repeatedly examined with a fiberlaryngoscope. Each part of the larynx was assessed for the degree of congestion, swelling, blister formation and impairment of laryngeal function, and the effects of these pathologies on breathing. RESULTS: Our observations showed that classification of inhalation injury according to anatomical division could not reflect the severity of the injury. For this reason, every changes in each part of the larynx was analyzed. A classification consisting of 3 types of laryngeal injury was proposed in respect to 3 predisposing factors of laryngeal obstruction. This classification could serve as a guide for treatment. CONCLUSION: A clearcut diagnosis of laryngeal inhalation injury is a pre-requisite for the choice of the correct treatment and the decision on the time for surgical intervention, thus laryngeal obstruction could be avoided, and death rate of early stage of inhalation injury could also be lowered.

Adult↗

PubMed1999

Expression of autotaxin mRNA in human hepatocellular carcinoma.

OBJECTIVE: To investigate the expression of autotaxin (ATX) mRNA existed in the human hepatocellular carcinoma (HCC), and whether there is relation between the level of ATX expression and clinicopathological features of HCC. METHODS: Five normal liver tissues and 32 histologically verified HCC specimens were obtained. Semi-quantitative reverse transcription polymerase chain reaction was used to detect mRNA expression of ATX. RESULTS: ATX was expressed in all 32 HCC and 5 normal liver tissues. The mean expression level of ATX gene in HCC samples was higher than that in normal liver tissues (68.23% +/- 15.31% vs. 31.97% +/- 8.05%, P < 0.001). Patients were divided into two groups: low ATX HCC (15 cases) and high ATX HCC (17 cases) by the cutoff point of median value. Intrahepatic metastasis, vascular invasion and poor differentiation were more frequently noted in HCC patients with high ATX expression than in patients with low ATX expression. CONCLUSION: ATX gene was found to be overexpressed in some HCC and correlated with HCC development and metastases.

Carcinoma, Hepatocellular↗

PubMed1999

The relationship between the c-jun mRNA expression and apoptosis of neurons in rat brain following perinatal ischemic-hypoxia.

OBJECTIVE: To investigate the relationship between c-jun mRNA and apoptosis of neurons following perinatal ischemic-hypoxia. METHODS: We set up a fetal rat model of perinatal ischemic-hypoxia by ligating unilateral uterine horn vessel of pregnant Wistar rats (21-day gestation). The contralateral horn vessel was not ligated and the fetuses in these uteri served as controls. Rat pups were delivered by cesarean section at the end of ischemic hypoxic insult and then the rats' brain tissues were collected in different points of time. In situ hybridization and TUNEL methods were used to detect the c-jun mRNA expression and neural cells apoptosis separately. RESULTS: The expression of c-jun mRNA in brain tissues began at 15 minutes, reached the first peak at 1-2 hours after ischemic-hypoxic insult and reduced gradually after 4 hours and the second peak at 24th hour after insult, gradually disappeared till 72nd hour. There were very low c-jun mRNA expression of hippocampus in the control group 24 h after birth. Meanwhile, we observed that the apoptosis of neuronal cells in cerebral cortex was much more than that in the control group. CONCLUSION: The increases of immediate early gene c-jun expression and the cell apoptosis could be induced by perinatal ischemic-hypoxia. The higher expression of c-jun mRNA might induce the transcription of its target gene, especially, so called "death related genes", which would be a promoter for cell apoptosis.

Animals↗

PubMed1999

An analysis of factors influencing electrocardiogram stress test for detecting coronary heart disease.

OBJECTIVE: To evaluate factors influencing electrocardiogram (ECG) stress test. METHODS: The treadmill stress test and coronary angiogram (CAG) records were reviewed retrospectively in 435 consecutive patients with chest pain between 1991 and 1997. There were 44 cases with normal CAG but positive exercise stress test results (false-positive, Group A), and 33 cases with both negative CAG and negative exercise test (true-negative, Group B). The baseline ECG, echocardiogram, abnormal systolic blood pressure response and history of diabetes mellitus and hypertension in the two groups were compared. RESULTS: There was no significant difference between the two groups with respect to age, gender, and antianginal medication. More patients in Group A had hypertension (52.3% vs 27.3%, P < 0.05) and diabetes mellitus (15.9% vs 0%, P < 0.05). Left ventricular (LV) hypertrophy in baseline ECG and by echocardiogram was more often present in Group A (25.0% vs 3.0%, P < 0.05; 36.4% vs 12.1%, P < 0.05). There were no significant differences between the two groups with respect to maximal heart rate, maximal systolic blood pressure (BP), metabolic equivalents, postexercise systolic BP, termination for exercise test, baseline ECG with bundle branch block and ST depression. CONCLUSION: Our results suggest that LV hypertrophy and a history of hypertension or diabetes mellitus are the main factors influencing ECG stress test for detecting coronary heart disease.

Adult↗

PubMed1999

Relationship between remodeling and function of left ventricle and angiotensin II AT1 receptor expression after myocardial infarction in rats.

OBJECTIVE: To determine the relationship between remodeling and dysfunction of left ventricle (LV) and the expression of the angiotensin II AT1 receptor mRNA after myocardial infarction (MI) in rats. METHODS: Nine MI rats (Group A) and 8 sham-operated rats (Group B) were studied by both Doppler echocardiography and Dot blot using Digoxingenin-labelled cDNA probes. RESULTS: Compared with Group B, Group A showed the increase in LV internal diastolic diameter (0.87 +/- 0.06 mm vs 0.66 +/- 0.03 mm, respectively, P < 0.01) and volume (0.73 +/- 0.09 ml vs 0.51 +/- 0.05 ml, P < 0.01). In addition, thinning of anterior wall, thickening of posterior wall, increasing of peak early filling velocity (peak E), decreasing of late filling velocity (peak A) and increasing of the E/A were demonstrated in MI rats 7 weeks after MI. The levels of the cardiac angiotensin II AT1 receptor mRNA in Group A were higher than those of Group B (2.2-fold). CONCLUSIONS: Seven weeks after MI in rats, character of LV remodeling and dysfunction were developed and the expression of cardiac angiotensin II AT1 receptor mRNA was increased.

Animals↗

PubMed1999

A brief history of antibiotic science.

As the greatest achievement in the history of microbiology, the story of antibiotic is an extremely inspired chapter in its history. Like the developmental process of other sciences, antibiotic reveals a history of first accumulating experience, followed by the stage of interpretation of the phenomena as other experimental study. Meantime, there is no end to the discovery of new antibiotics. Currently, the scope and province of antibiotic research is expanding both in its profundity and coverage.

Anti-Bacterial Agents↗

PubMed1999

[Endoluminal stent-graft for aortic aneurysms: a report of six cases].

OBJECTIVE: To explore the clinical value of the treatment of aortic aneurysms with endovascular stent-graft prostheses. METHODS: Six patients were included in the study. 4 patients with infrorenal abdominal aneurysms involving the aortic bifurcation and the common iliac arteries received bifurcated stent-grafts; 1 patient with descending and abdominal aortic aneurysm received straight stent-graft; and 1 patient with right common iliac artery aneurysm received straight stent-graft. After a unilateral surgical arteriotomy, the endoprostheses were advanced through the femoral arteries and placed under the guidance of fluoroscope. CT and MRI were perfomed during the follow-up of 2-16 months. RESULTS: All patients got a primary success. The aortic aneurysms were completely excluded from the circulation. Two cases had a prolonged fever; 1 case was found a leakage 3 months later. CONCLUSION: Our results suggest that endovascular treatment of aortic aneurysm is technically feasible and it can effectively exclude aortic aneurysms from the circulation. With further refinement, endoluminal repair may emerge as an interventional strategy to treat infrarenal aortic aneurysm, especially for patients at high surgical risk.

Adult↗

PubMed1999

[Dynamic changes and localization of plasma heparin cofactor II before and after delivery in hypertensive pregnancy].

OBJECTIVE: To explore the physiological significance of the anticoagulation effect of heparin cofactor II (HCII) in vivo and investigate the pathogenesis of the development of thrombosis in hypertensive pregnancy. METHODS: 1. Plasma level of HCII activity was measured by chromogenic assay in 18 healthy adults, 18 normal pregnant women and 29 hypertensive pregnant women before and after delivery. 2. Plasma level of HCII antigen was measured by Western blot in 29 hypertensive pregnant women before and after delivery. 3. The distribution of HCII in the placenta was determined by immunofluorescent method. RESULTS: The plasma HCII activity and antigen content in hypertensive pregnancy decreased significantly before delivery. They correlated with the severity of hypertensive pregnancy, and restored to normal after delivery. No HCII was found in normal and pathological placenta. CONCLUSION: 1. Plasma HCII activity decreased during pregnancy in hypertensive pregnancy. 2. The placenta is not the target of HCII. 3. Dynamic determination of plasma HCII level can reflect the severity of hypertensive pregnancy and be used as one of prognostic indices.

Adult↗

PubMed1999

[Effects of homocysteine on human vascular endothelial cells, platelet aggregation and heparin cofactor activity].

OBJECTIVES: To elucidate partly the mechanism of homocysteine-associated thrombosis. METHODS: 1. Thrombomodulin (TM) antigen distribution on human vascular endothelial cell (EC) membrane was assayed by immune-fluorescence histochemistry stain and flow cytometry; 2. Plasma heparin cofactor activity was measured by chromogenic method. RESULTS: Homocysteine (Hcy) significantly down-regulated the expression of TM on EC, with a concentration-dependent manner; 2. Hcy did not influence platelet aggregation induced by ADP and thrombin; 3. Hcy exerted no effects on the activities of antithrombin III or heparin cofactor. CONCLUSION: The effect of Hcy in developing thrombosis may be associated with an inhibitory action on EC TM expression; which was independent of platelet aggregation or heparin cofactor activity.

Adult↗

PubMed1999

[Study of apoptosis induced by indomethacin in chronic myeloid leukemia].

OBJECTIVE: To explore the effect of indomethacin(IN) on the apoptosis of chronic myeloid leukemia(CML) cells, and its molecular mechanisms, for the purpose of screening a new antileukemic agent. METHODS: CML cell line K562 and fresh bone marrow cells from 6 untreated Ph+ CML patients were used for in vitro culture study. The effects of IN on cells were determined by cell morphology, flow cytometry, DNA electrophoresis, and RT-PCR. RESULTS: 1. IN induced apoptosis of K562 and fresh CML cells and inhibited the proliferation of K562 cells. 2. A synergic effect of inducing K562 cell apoptosis was observed when IN combined with Vp16. 3. IN down-regulated the level of bcl-2 mRNA without changing the level of bax mRNA in K562 cells. CONCLUSION: IN can induce apoptosis and inhibit proliferation in CML cells, and increase the sensitivity of CML cells to Vp16. Down-regulation of bcl-2 mRNA may be one of the mechanisms of CML cell apoptosis induced by IN.

Apoptosis↗

PubMed1999

Investigation of parvovirus B19 in cardiac tissue from patients with congenital heart disease.

OBJECTIVE: To explore the correlation between human parvovirus B19 (HPV-B19) and congenital heart (CHD) and to investigate the teratogenic effect of HPV-B19. METHODS: A case control study was conducted to investigate the embedded autopsy cardiac tissues of 29 cases of CHD and 30 controls without CHD with nest polymerase chain reaction (PCR). Other viruses, including herpes simplex virus (HSV). Toxoplasma gondii (TOX), cytomegalovirus (CMV) and rubella virus (RV) were also studied in 10 cases of each group with corresponding PCR kits. RESULTS: Five of 29 (17.2%) CHD cases were positive for HPV-B19, while all the 30 controls were negative for HPV-B19 (P=0.0237). All cases studied were negative for both HSV and TOX. Three cases in each group were positive for CMV, with presence of HPV-B19 DNA in 2 cases in the CHD group. Only two cases in the CHD group showed positive reaction for RV. CONCLUSIONS: As far as we know, it is the first report of the presence of HPV-B19 in cardiac tissues of CHD patients. The detection rate of HPV-B19 DNA is significantly different between the two groups, inferring that HPV-B19 might be correlated with CHD.

Adolescent↗

PubMed1999

[Analysis on curative effects of teeth with chronic apical periodontitis in elderly people].

OBJECTIVE: To study of the curative effect of teeth with chronic apical periodontitis in elderly people and the usage of assessment index. METHODS: Fifty eight teeth from 49 elderly and 50 teeth from 40 young patients were reexamined, which had received root canal therapy or resinifying therapy 2 to 9 years ago. The curative effects were evaluated based on clinical examination and radiographic assessment using periapical index (PAI). RESULTS: Statistically no significant difference for the overall healing rates between the two groups. But when the reexamination period was longer than 4 years, the healing rates in elderly people (58.0%) were significantly lower than those of the young people (87.1%). The treatment method and the size of the periapical lesion had significant influence on the results of the elderly people, whereas no influence on the young patients. According to our data, deep periodontal pocket and occlusal trauma were the main reasons of failure. CONCLUSION: The long-term curative effects of teeth with chronic apical periodotitis in elderly is lower than that of the young people. The PAI system is worth of utilizing popularly in the clinical dentistry.

Adolescent↗

PubMed1999

[Absorbed doses to critical organs from full mouth dental radiography].

OBJECTIVE: A few studies were reported in China on radiological risk of dental radiography. The aim of this study is to evaluate the absorbed doses of patients from the full mouth radiographs, and to find out the contribution from each projection to the total absorbed dose of the organs. METHODS: Absorbed doses to critical organs were measured from 14-film complete dental radiography. The organs included pituitary, optical lens, parotid glands, submandibular glands, sublingual glands, thyroid, breasts, ovary, testes and the skin in center field of each projection were studied. A-radiation analog dosimetry system (RANDO) phantom with thermoluminescent dosimeters (ILD200) was used for the study. All of the exposure parameters were fixed. The total filtration was 2 mm Al equivalent. The column collaboration was 6 cm in diameter and 20 cm in length. The absorbed doses of organs were measured three times in each projection of the full-mouth series (FMS) exposures. RESULTS: The absorbed dose of lenses in FMS (249 microGy) in present study was much less (10%) than the doses (2,630 microGy) reported in 1976. The doses absorbed of other organs in the present study were thyroid gland (125 microGy), pituitary gland (112 microGy), parotid gland (153 microGy), submandibular gland (629 microGy), sublingual gland (1,900 microGy), and breast gland (12 microGy). The doses of the ovary and testis were to small to further analysis. CONCLUSION: All of the results show that the radiation risk to patients in intraoral radiograph has been reduced significantly. In the pituitary, half of the dose is from both sides of the maxillary molar projection. For the lenses, the largest contribultions of radiation (60%) come from the ipsilateral molar and premolar projection of maxilla. In parotid gland, up to 57% of the dose is from the contralateral molar, pre-molar and canine of maxilla. It could be derived that about 90% of the absorbed doses could be avoided in FMS if the column collimator is 20 cm long and the filter is 2.0 mm thick. If we use the 10-film complete mouth radiograph instead of the 14-film series, more 20% of the doses would be reduced.

Absorption↗