Biomedical subjects

D Fang

Publications and source records attributed to D Fang.

At least 55 records · Page 3Linked to original sources

PubMed1999

[Study of recurrence and metastasis after radical resection of carcinoma of the lung].

OBJECTIVE: To study the characteristics of recurrence and metastasis following radical resection of carcinoma of the lung. METHODS: A total of 1,229 cases of radically resected lung cancer was statistically analyzed using STATA software. The survival rate was estimated using life table method. Comparisons of survival in each group were made according to the log rank test. The differences in rate between groups was assessed by chi 2 test. RESULTS: Recurrence rate was found higher in squamous-cell carcinoma than in adenocarcinoma. It was also higher in sleeve resection and partial resection than in other resection modes (P < 0.05). The rate of lymph node metastasis was higher in adenocarcinomas than in squamous-cell carcinoma (P < 0.05). Lung, bone, brain, liver, subcutis, and adrenal glands were the common resorts of metastasis, in decreasing order of frequency. Metastatic rate was the lowest in squamous-cell carcinoma. Active therapy can still improve the survival even when recurrence and metastasis occurred. CONCLUSION: It is recommended to avoid partial resection for the invaded adjacent lobe whenever patient's condition can stand multilobectomy. It is necessary to assure resection margin length when sleeve resection is performed in order to reduce recurrence. Active therapy can improve survival of patients with recurrence and metastasis.

Adenocarcinoma↗

PubMed1999

[The detection of microsatellite instability in carcinoma and adenoma of large bowel and its significance].

OBJECTIVE: To explore the role of microsatellite instability (MSI) in colorectal carcinogenesis and the relationship between MSI, proliferation activity and prognosis. METHODS: PCR-SSLP and immunohistochemistry methods were used to detect MSI and the expression of PCNA in 56 cases of carcinomas, 9 cases of adenomas and 6 cases of adenomas with malignant changes. RESULTS: The total positive rate of MSI were 25/56 cases in colorectal carcinomas. The MSI positive cases were 3/4 in HNPCCs, 22/52 in sporadic colorectal carcinomas, 2/9 in adenomas and 2/6 in adenoma with malignant changes respectively. The PCNA labelling index of MSI positive tumors were significantly lower than that of MSI negative tumors (P < 0.01). The 3 and 5 year survival rates in patients with MSI positive colorectal carcinomas were higher than those of MSI negative tumors. CONCLUSION: MSI may be an early molecular alteration and another molecular mechanism in colorectal carcinogenesis. The MSI positive tumors have low proliferating activity and a better clinical outcome. The detection of MSI might be useful in predicting prognosis of colorectal carcinomas.

Adenoma↗

PubMed1999

[A study on the loss of heterozygosity of multiple tumor suppressor genes in gastrointestinal metaplasia].

OBJECTIVE: To investigate the role of multiple tumor suppressor gene abnormality in gastrointestinal metaplasia (IM). METHODS: The loss of heterozygosity (LOH) of YNZ22, APC, MCC and DCC genes was examined by PCR-RFLP technique in 60 IM cases. RESULTS: LOH of YNZ22, APC, MCC and DCC genes were found in 19.4% (6/31), 12.0% (3/25), 13.0% (3/23) and 4.3% (2/47) respectively. IM was classified into types I, II and III. It was found that the LOH rates of each tumor suppressor gene of type III IM were higher than those of types I & II IM, but the difference was not significant (P > 0.05). Two cases of type III IM were found to also have 2 gene alterations (APC, MCC or YNZ22, MCC) respectively. All LOH were found in IM of adjacent carcinoma. None were found in IM of cancer-free patients. CONCLUSION: The alteration of tumor suppressor gene may play a role in the development and carcinogenesis of IM.

DNA↗

PubMed1999

[Isolation of isoforms of apolipoprotein CIII from human serum by chromatofocusing].

This study aimed to isolate isoforms of apolipoprotein (apo) C III from human serum. 24-hour fasting serum from normal and hyperlipidemic subjects was pooled and subjected to ultracentrifugation at plasma density for 20 hours. Very low density lipoprotein (VLDL) was collected at density of d < 1.006 g/ml, and it was delipidated by ethanol and ether. The delipidated apo-VLDL was dissolved in a solution containing 7.2 mol/L urea and 20 mmol/L dithiothreitol. The insoluble apo B was removed by centrifugation. The soluble apo-VLDL was applied to PBE94 column, and eluted with elution buffer containing polybuffer 74 and 8 mol/L urea (1:8, pH4.0). After pooled, the eluted peaks of apolipoproteins were applied to column chromatography of hydroxylapatite to remove the polybuffer. The purified isoforms of apoC III and the purified apo C I, C II and E, were characterized by isoelectrofocusing and west blot. The results showed that the purified apoC III1, C III2, and C II were pure.

Apolipoprotein C-III↗

PubMed1999

Geographic mobility of the foreign-born Chinese in large metropolises, 1985-1990.

"The spatial assimilation and ethnic resources models, two major theoretical explanations of the adaptation of immigrants, provide different views on the mechanism of spatial mobility of immigrants. We used the 1990 census 5 percent Public Use Microdata Sample (PUMS) to analyze the migration of foreign-born Chinese in three large metropolises--New York, Los Angeles, and San Francisco. We tested the two explanations in this study and argue that our results largely support the assimilation model. In addition, we contend that macroeconomic conditions of ethnic enclaves and characteristics of ethnic economies are also important in affecting the geographic redistribution of immigrants." This paper was originally presented at the 1996 Annual Meeting of the Population Association of America.

Acculturation↗

PubMed1999

[A mutation specific polymerase chain reaction for detecting hepatitis B virus genome with A-to-C mutation at nt585].

OBJECTIVE: To investigate the prevalence of hepatitis B virus (HBV) nt585 A-to-C mutants in China. METHODS: A mutation specific polymerase chain reaction (msPCR) was established for amplifying HBV DNAs with A-to-C mutation at nt585. Two sets of primer pairs with same sequences except for one base at 3' terminus were designed and synthesized according to 48 of the known HBV genome sequences and the popular HBV subtypes, adr and adw, in China. RESULTS: 57 of HBV S gene fragments amplified by a nested PCR from different and child adult hepatitis B patients were characterized by using the msPCR. It was shown that HBV mutants with A-to-C mutation at nt585 could be confirmed. CONCLUSION: The msPCR is a specific and sensitive method for detecting the HBV nt585 A-to-C mutants.

Adult↗

PubMed1999

Study of loss of heterozygosity at DCC and APC/MCC genetic loci of gastric cancer.

In order to assess the role of the changes of DCC and APC/MCC genes in the development and progression of gastric cancer, the loss of heterozygosity (LOH) of these genetic loci was investigated in 45 surgical specimens of gastric cancer with PCR-RFLP. The rate of LOH was 30.0% (9/30) at APC/MCC gene and 33.3% (15/45) at DCC gene. LOH was found in both intestinal and gastric types of gastric cancer and the rate of LOH of DCC gene was significantly higher in stages III to approximately IV gastric cancer (48.0%) than in stages I to approximately II (15.0%) (P<0.05). LOH of APC/MCC gene could be found in both early and advanced stages of gastric cancer. These findings suggest that changes of DCC and APC/MCC genes are involved in the development and progression of the intestinal and gastric types of gastric cancer.

Adenocarcinoma↗

PubMed1998

Comparative health risk assessment of nuclear power and coal power in China.

The public health risk of ionising radiation released from the coal-fired energy chain, 20 deaths (GW a)(-1), is about 18 times that of the nuclear energy chain, 1.1 deaths (GW a)(-1), in China. The main contributors to the fatality risk for the former are the public dose caused by the use of coal ash and the occupational exposure caused by radon and its progeny in coal mines. The total health risk (but excluding low probability/high consequence accidents) of the coal-fired energy chain, 57.1 deaths (GW a)(-1), is about 12 times of that of the nuclear energy chain, 4.6 deaths (GW a)(-1). The health risk of coal-fired energy chain could be significantly reduced if technique and management were improved. Even then the risk of the coal-fired energy chain is about 4.4 times that of the nuclear energy chain.

China↗

PubMed1998

Dentin-specific proteins in MDPC-23 cell line.

Only four established odontoblast-like cell lines have been reported in the literature (1-6). Of the four, only two synthesize dentin-specific proteins. These studies report that the cell line MO6-G3 synthesizes phosphophoryn (DPP), dentin sialoprotein (DSP) and dentin matrix protein-1 (DMP-1) while MDPC-23 synthesizes DSP, but not DMP-1. The objective of the present study was to determine whether polyclonal antibodies to rat DSP and DPP would label odontoblasts on microscopic sections of day-19 fetal mouse incisor odontoblasts as well as cultured cells of the MDPC-23 cell line. The spontaneously immortalized MDPC-23 cell line was derived from fetal mouse molar papillae, made continuous by the 3T6 method and cloned by dilution. These cultures have been passaged 77 times after cloning, form multilayered nodules, and have high alkaline phosphatase activity. The data show positive reactivity in odontoblasts in 19-d mouse fetal incisors as well as in cultures of MDPC-23 cells by fluorescence and confocal microscopy. In addition, these cultures were characterized by phase microscopy and scanning and transmission electron microscopy. These findings suggest that MDPC-23 cells are of the odontoblast lineage.

Animals↗

PubMed1998

Stereological studies of the effects of alpha-MSH and cAMP on melanosomes in melanoma cells.

The effects of alpha-MSH and cAMP on melanosomes in Cloudman S91 melanoma cells were investigated by modern stereological techniques. Cells were cultured for 4 days in medium containing alpha-MSH or cAMP, harvested at 24 hour intervals; some were frozen for melanin assay and the reminder embedded in Epon for light and electron microscopy. Cellular and melanosomal parameters were estimated by new stereological probes. We found that both stimulators induced increases in nuclear volume, cell volume, and the volume fractions and volumes of premelanosomes (V(Vpm,cell), Vpm) and mature melanosomes (V(Vmm,cell), Vmm), and the number of mature melanosomes (Nmm). Both stimulators also caused declines in the volume of individual mature melanosomes (V(Vimm)), the melanin content per mature melanosome unit volume and the melanin content per individual mature melanosome. The increases in the volume of individual premelanosomes and the number of premelanosomes were only induced by cAMP. The effect cAMP on some parameters occurred 24 hours prior to alpha-MSH and was more marked. The response of premelanosomes to the stimulators was more sensitive than mature melanosomes. These results suggest that both stimulators enhanced melanogenesis by increasing the V(Vpm,cell), V(Vmm,cell), Vpm, Vmm and Nmm. The melanogenic level did not depend on the V(Vimm) and melanin concentration in melanosomes. The maturation of premelanosomes was involved in melanogenesis induced by both stimulators, but, de novo synthesis and enlargement of premelanosomes were only stimulated by cAMP. It imply that exogenous cAMP may affect melanosomes, and hence melanogenesis in quantitatively or qualitatively different ways to alpha-MSH.

Cell Count↗

PubMed1998

Estrogen increases sensitivity of hepatic Kupffer cells to endotoxin.

The relationship among gender, lipopolysaccharide (LPS), and liver disease is complex. Accordingly, the effect of estrogen on activation of Kupffer cells by endotoxin was studied. All rats given estrogen intraperitoneally 24 h before an injection of a sublethal dose of LPS (5 mg/kg) died within 24 h, whereas none of the control rats died. Mortality was prevented totally by pretreatment with gadolinium chloride, a Kupffer cell toxicant. Peak serum tumor necrosis factor-alpha (TNF-alpha) values as well as TNF-alpha mRNA in the liver after LPS were twice as high in the estrogen-treated group as in the untreated controls. Plasma nitrite levels and inducible nitric oxide synthase in the liver were also elevated significantly in estrogen-treated rats 6 h after LPS. Furthermore, Kupffer cells isolated from estrogen-treated rats produced about twice as much TNF-alpha and nitrite as controls did in response to LPS. In addition, Kupffer cells from estrogen-treated rats required 15-fold lower amounts of LPS to increase intracellular Ca2+ than controls did, and Kupffer cells from estrogen-treated animals expressed more CD14, the receptor for LPS/LPS binding protein, than controls. Moreover, estrogen treatment increased LPS binding protein mRNA dramatically in liver in 6-24 h. It is concluded that estrogen treatment in vivo sensitizes Kupffer cells to LPS, leading to increased toxic mediator production by the liver.

Acute-Phase Proteins↗

PubMed1998

[Repair of massive bone defect with free vascularized fibular graft].

In the study of repair of massive bone defect with free vascularized fibula graft, 13 cases were reported, in which traumatic defect in 7 cases, segmental resection of bone from tumors in 5 cases and osteomylitis in 1 cases. They all were treated successfully with vascularized fibular graft. After a follow-up of 6 months to 7 year, bone healing was observed with satisfactory and rehabilitation of functions. In one case, fatigued fracture occured twice due to early walking. It was concluded that free vascularized fibular graft was very helpful in the repair of massive bone defect, but prolonged external fixation after operation might be important to prevent fractur of grafted bone.

Adult↗

PubMed1998

[Surgical treatment results for carcinoma of the gastric cardia in 1832 cases].

OBJECTIVE: To evaluate the results of surgical treatment for carcinoma of the gastric cardia and the prognostic factors. METHODS: The prognostic factors were assessed with 5-year survival rates which was estimated using life table method in 1832 cases. The difference between groups was assessed by the log rank test. RESULTS: The overall resection rate was 76.3% and the radical resection rate 53.4%. The overall 5-year survival rate was 23.5% while in patients treated with curative resection it was 29.9%. The 5-year survival rate was 29.4% in patients received preoperative radiation and 21.5% in patients treated with surgery alone (P > 0.05). Patients whose upper margin of resection was longer than 5 cm away from the tumor had higher 5-year survival rate (25.8%) than those with margin of resection less than 5 cm (18.4%). The difference was statistically significant (P < 0.05). CONCLUSION: Preoperative radiation can increase the survival rate, but it was not statistically significant. Increasing the margin of resection to > 5 cm can improve survival.

Adenocarcinoma↗

PubMed1998

[The carcinogenetic and tumor-promoting effects of concentrated Helicobacter pylori culture supernatant in rats].

OBJECTIVE: To investigate the carcinogenetic and tumor-promoting effect of concentrated Helicobacter pylori culture supernatant (CHCS). METHODS: 0.25% and 0.5% CHCS in drinking water administered orally for 52 weeks in rats, the changes of mucosal thickness, adherent mucosal mucus amount, DNA synthesis rate and precancerous lesions incidence in different times were examined, and the promoting effect of CHCS used in different periods on experimental carcinogenesis induced by MNNG was also clarified. RESULTS: Decreased mucosal thickness and amount of mucosal adherent mucus, increased DNA synthesis were found after CHCS feeding for 5 weeks in a dose- and time-dependent manner. By the end of the experiment at the 52nd week, the incidence of intestinal metaplasia(IM), sulfomucin positive IM and dysplasia in 0.5% CHCS group(57%, 39%, 18% respectively) were significantly higher than those in 0.25% CHCS group(28%, 10%, 3% respectively) and control group(7%, 0%, 0% respectively). Whenever CHCS was used prior to, together with, or following MNNG administration, the incidences of gastric cancer and precancerous lesions were significantly increased in comparison with those in the rats treated with MNNG alone. CONCLUSION: Hp cytotoxin(s) may have direct carcinogenetic and tumor-promoting effects.

Animals↗

PubMed1998

[Telomerase activity in gastric cancer and premalignant lesions: determination and its clinical significance].

OBJECTIVE: To evaluate the role of telomerase activity in the development and progression of gastric cancer (GC) and if knowedge of telomerase activity may be an indicator for the early diagnosis and poteneial treatment of GC. METHODS: Using PCR-based TRAP (telomeric repeats amplification protocol) assay, we examined telomerase activity in 176 samples of gastric mucosa. Meanwhile, some tumor tissues were also analyzed by serial dilution. RESULTS: Telomerase activity detected in chronic atrophy gastritis (CAG), intestinal metaplasia (IM); dysplasia (Dys); and gastric cancer (GC) was 24.6% (14/57), 38.9% (7/18), 37.5% (3/8), and 92.3% (60/65) respectively; which was significantly higher than that in normal tissues (NT) (P < 0.01-0.05). Telomerase activity in group of GC was also significantly higher than that in group of CAG, IM and Dys (P < 0.01). Frequencye and levels of telomerase activity were not associated with patients' sex, tumor location, size gross type, depth of invasion, lymph node metastases, differentiation and clinical stage. CONCLUSION: Telomerase activity is detected not only in GC tissues, but also in some premalignant lesions or diseases.

Gene Expression Regulation, Enzymologic↗

PubMed1998

[Detection of HGV NS5 antigen in liver tissue of patients with chronic liver disease].

OBJECTIVE: To investigate the existence of hepatitis G virus (HGV) in liver tissue. METHODS: HGV NS5 antigen was detected by immunohistochemical method in paraffin-embeded liver tissue of autopsy patients with chronic liver disease. RESULTS: Among 110 samples, 32.7% (36/110) had been detected out HGAg in their liver. When serologica marker was used, the detection rate was 21% (4/19) in HNA-E, 36% (25/69) in HBV and 32% (7/22) in HCV infectious group, respectively. HGAg expression in hepatocytes was also found pathologically in 22% of 45 patients with active cirrhosis, 43% of 47 patients with hepatocellular carcinoma, and 33% of 18 patients with chronic fulminent hepatitis. The staining signal of HGV NS5 antigen was mainly located in the cytoplasm of liver or neoplasm cells, and the positive cells were distributed diffusely in pseudolobule or liver tissues. CONCLUSION: The infection of viral G is often seen in liver tissue of patients with chronic liver disease.

Adult↗

PubMed1998

[Microsatellite instability in gastric carcinoma and intestinal metaplasia].

OBJECTIVE: To investigate the role of microsatellite instability (MSI) in the carcinogenesis and development of gastric cancer (GC). METHODS: MSI was examined in 50 surgically resected gastric cancer specimens and 15 intestinal metaplasia specimens using PCR based methods. RESULTS: MSI was detected in 27/50 of GC and 3/15 of intestinal metaplasia at one or more loci. MSI was positive in all three cases of early GC. The incidence of MSI in well differentiated GC (86.6%) was significantly higher than that in poorly differentiated GC (P < 0.05). The frequency of MSI in intestinal type of GC (77.8%) was significantly higher than that in the diffused type (40%, P < 0.05). No significant correlation was found between MSI and age, sex, size, location, lymph node metastasis or clinical stage of GC. CONCLUSION: MSI is an early molecular marker in the carcinogenesis of GC and may play an important role in the development of GC.

Adenocarcinoma↗

PubMed1997

[A study on the loss of heterozygosity at 17p13.3 and abnormal expression of p53 protein in gastric carcinoma].

OBJECTIVE: To evaluate the role of 17p13.3 loss and abnormal expression of p53 in the development and progress of gastric carcinoma. METHODS: The loss of heterozygosity (LOH) at 17p13.3 and abnormal expression of p53 gene were examined with PCR-RFLP and immunohistochemical methods in 51 surgical specimens of gastric carcinoma. RESULTS: LOH at 17p13.3 was detected in 16/31 cases (51.6%) and positive staining for p53 protein was found in 19/51 cases (37.3%). No significant correlation was found between LOH at 17p13.3 and abnormal expression of p53 or between these two events in any clinicopathological parameters. LOH was found in one cases of early gastric cancer. CONCLUSIONS: These results suggest that LOH at 17p and abnormal expression of p53 protein are frequently found in gastric carcinoma and may play an important role in the carcinogenesis and progress of both intestinal and gastric types of gastric cancer.

Adenocarcinoma↗