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Biomedical subjects

F Han

Publications and source records attributed to F Han.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Distribution and transferring of carbon in kast soil system of peak forest depression in humid subtropical region].

Taking Guilin Yaji Karst Experiment Site as an exemple and with the methods of field monitoring and laboratory analysis, this paper studied the distribution and transferring of carbon in the karst soil system of peak forest depression in the humid subtropical region of China. The carbon pools in biomass, litters and soil organic matter(SOM) and their mobility as expressed by oxidizability and decomposition rate of SOM, the concentration of soil CO2 and the emission rate of CO2 from soil were investigated. The mobile carbon pool in the system supplied a rich source of CO2, which drived the karst process. When active karst process happened in Spring and Summer, over 60% of carbon in the output water was derived from soil CO2, as traced by delta 13 C distribution in the system. Therefore, owing to the carbon transfer in the pathway of air-plant-soil-water, karst process took place rather under soil-rock-water interface than under air-rock-water interface. Thus, the epigenetic karst process was driven and accelerated by soil as an interface of carbon environmental geochemistry.

Carbon↗
PubMed2000

[Some geographical features of the location and gene mutation of cancers occurring in Nantong City, China].

OBJECTIVE: To detect the location and geographical features of gene mutation of the cancer based on 30,709 clinical tumor biopsies. METHODS: Thirty thousand seven hundred and nine cases of tumor biopsy materials were collected from the Department of Pathology of Nantong Cancer Hospital between June 1974 and December 1987. The address of the village and county of patients was collected and statistical analysis was performed on data from lab examination. DNA sequencing of 31 cases of hepatocellular carcinoma (HCC) was performed at the Department of Pathology of the Medical College of Tokyo University, Japan. RESULTS: The data suggested that different carcinomas occurred predominantly in some districts and the frequency and type of mutation of the P53 gene in the HCC were different in different districts. CONCLUSION: It seems that based on the clinical biopsy materials, carcinomas of the uterus cervix (CC) and nasopharynx tend to occur in some districts of Nantong City and the frequency and type of mutation of the gene P53 of the HCC were different in different districts. The reason for this is not understood and further study will be done.

China↗
PubMed2000

In situ RT-PCR detection of inducible nitric oxide synthetase gene expression in lung during endotoxemia in rabbits.

OBJECTIVE: To detect the location of inducible nitric oxide synthetase (iNOS) protein and mRNA in lung during endotoxemia in rabbits. METHODS: Northern blotting was performed before, 1 hour and 5 hours after the intravenous administration of lipopolysaccharide (LPS) in rabbits. Immunohistochemical analysis (IA), in situ hybridization and in situ reverse transcription-polymerase chain reaction (in situ RT-PCR) were also performed in lung sections. RESULTS: iNOS mRNA expression was found using Northern blotting in lung 5 hours after LPS injection, while it was not found in control. The positive stain was found only in macrophages in lung 5 hours after LPS injection by standard hybridization and IA; while by in situ RT-PCR, the amplification products were found in macrophages, airway epithelial cells, vascular endothelial cells, smooth muscle cells and leukocytes, in addition to macrophages distributed abundantly throughout the lung. The signal was absent in control or samples. CONCLUSIONS: Using an in situ RT-PCR technique, iNOS expression was not only observed in macrophages but also in many other kinds of cells in lung during endotoxemia in rabbits. This suggests that in situ RT-PCR is much more sensitive than in situ hybridization, and can be used to examine genes with low expression.

Animals↗
PubMed2000

Protective effect of melatonin on neural cells against the cytotoxicity of oxyradicals.

OBJECTIVE: To investigate the exact mechanism of melatonin to prohibit the apoptosis of neural cells induced by various kinds of cytotoxic agents. METHODS: We used the methods of phase contrast microscopy, MTT assay and hoechst dye staining to check this mechanism in SKNSH and U251 cell lines. RESULTS: Both 2 mmol/L H2O2 and 0.5 micromol/L amyloid beta-protein (Abeta) induce these two cell lines die via apoptosis. Either melatonin or glutathione can significantly protect both cell lines. The protective effect of 10 micromol/L melatonin is as same as that of 60 micromol/L glutathione. CONCLUSION: Melatonin can partly inhibit the cytotoxicity of H2O2 and Abeta through its role as a free radical scavenger.

Amyloid beta-Peptides↗
PubMed1999

Different frequencies of p53 codon-249 hot-spot mutations in hepatocellular carcinomas in Jiang-su province of China.

Environmental carcinogens often induce specific mutations in the p53 gene, apparent in tumors. The relation between aflatoxin B1 (AFB1 )-related hepatocellular carcinomas (HCCs) and hot spot at codon 249 of the p53 gene has received a great deal of attention, but its significance is still controversial. To clarify this problem, we analyzed the p53-mutational status of HCCs in Jiang-su province in China, where AFB1 contamination of the staple food significantly differs between the northern and southern parts (prominent only in the latter), while other conditions are quite similar. Background liver status and mutations in exons 5 to 8 of p53 in a total of 31 cases were divided approximately equally between the 2 areas. In all, 15 tumors exhibited a total of 17 mutations in the p53 gene; 9 cases from the southern part of the province had the hot-spot mutation at codon 249 (9/16, 56%), but only one case from the northern part (1/15, 8%). These results suggest that AFB1 contamination may correlate with codon-249 mutations in HCC.

Adult↗
PubMed1999

Pteridine analysis in urine by capillary electrophoresis using laser-induced fluorescence detection.

Pteridines are a class of compounds excreted in urine, the levels of which are found to elevate significantly in tumor-related diseases. For the first time, we have developed a method, based on high-performance capillary electrophoresis (HPCE) and laser-induced fluorescence (LIF) detection, to monitor the pteridine levels in urine. HPCE provides better separation than high-performance liquid chromatography and the LIF detector enables us to detect minute amounts of pteridines in body fluid. Eight different pteridine derivatives were well separated in 0.1 M Tris-0.1 M borate-2 mM EDTA buffer (pH 8.75) using a 60-cm fused-silica capillary (50-micron i.d., 35-cm effective length), six of which were detected and characterized in urine samples from normal persons and different cancer patients. The detection limits of these pteridines are under 1 x 10(-10) M. The levels of neopterin, pterine, xanthopterin, and pterin-6-carboxylic acid were found to be significantly elevated in urine excreted by cancer patents, while the level of isoxanthopterin dropped in these patients. No significant change of biopterin level was found between healthy individuals and cancer patients. This method can be used in clinical laboratories either for cancer monitoring or for precancer screening.

Electrophoresis, Capillary↗
PubMed1999

Application of capillary nongel sieving electrophoresis for gene analysis.

Capillary electrophoresis (CE) has proved to be a strong tool for DNA analysis and has found abundant applications in the fields of restriction fragment sizing, mutation screening, polymerase chain reaction (PCR) product characterizing and forensic identifying. CE may be the main alternative to slab gel electrophoresis. Capillary nongel electrophoresis is the most favorable mode when aiming for this purpose because of its advantages of long lifetime, easy operation, good reproducibility, and low expense. In this paper, a new kind of sieving matrix, with mannitol as the additive for capillary electrophoresis, as well as related methods and their application for gene analysis were reported. Nine DNA fragments amplified by multiplex PCR from a normal dystrophin gene were well separated by this system. Three different deletions were found in Duchenne muscular dystrophy (DMD) patients. Three to four copies of the sex-determination region of the Y chromosome (SRY) gene, as well as the phenylalanine hydroxylase (PAH) gene, could be detected in mixed samples. The frequencies of short tandem repeats (STR) in PAH genes was analyzed in 61 normal Chinese individuals and 6 phenylketonuria families. One case of prenatal gene diagnosis was performed. By using this matrix, CE coupled with reverse transcription PCR (RT-PCR), the analysis of the alternative splicing expression pattern of the fragile X mental retardation 1 (FMR1) gene in adult lung tissue was achieved.

Adult↗
PubMed1999

Experience with the rectus abdominis myocutaneous flap with vascularized hard tissue for immediate orbitofacial reconstruction.

For a considerable tissue defect of the orbitofacial region after skull base or head and neck tumor en bloc extirpation, we have developed the "flying buttress" technique using the vascularized hard tissue rather than the multi-stage operative method using bone graft or alloplastic materials. The procedure reconstructs the inferior orbital rim and the zygomatic prominence--flying buttresses bridging transversely in a missing face--with free flap coverage, simultaneously in the primary surgery so that the bony structure is maintained for years and ptosis of a large flap is minimized. We prefer to use the rectus abdominis myocutaneous flap for tissue restoration and two types of vascularized hard tissue: the costal cartilages combined with the flap and the temporalis muscle-pedicled calvarial bone. Representative cases are illustrated and the technique is detailed.

Adolescent↗
PubMed1999

Sequence analysis of a rice BAC covering the syntenous barley Rpg1 region

In the course of map-based cloning of the barley stem rust resistance gene Rpg1, we identified a rice bacterial artificial chromosome (BAC) containing the Rpg1 flanking markers. Based on the excellent gene order colinearity between barley and rice in this region, we expected that this rice BAC would contain the barley Rpg1 homologue. In order to identify the putative rice homologue, we sequenced ca. 35 kb of the rice BAC at random and then an additional 33 kb of contiguous sequence between the two most closely spaced Rpg1 flanking markers. Sequence analysis revealed a total of 15 putative genes, 5 within the 33-kb contiguous region. A rice Rpg1 homologue was not identified, although a gene encoding a hypothetical polypeptide with similarity to a membrane protein could not be eliminated as a candidate. Surprisingly, four of the genes identified in the 33-kb contiguous rice sequence showed a high degree of similarity with genes on Arabidopsis chromosome 4. The genome regions harboring these genes showed some relatedness, but many rearrangements were also evident. These data suggest that some genes have remained linked even over the long evolutionary separation of Arabidopsis and rice, as has also been reported for mammals and invertebrates.

Journal Article↗
PubMed1999

Effects of sodium hyaluronate on experimental osteoarthritis in rabbit knee joints.

The aim of this study was to examine the effects of intraarticular administration of hyaluronan (HA) on cartilage degradation. Using a partial menisectomy model of osteoarthritis (OA) in the rabbit knee, the authors investigated the catabolic and anabolic changes induced by intraarticular injection of HA. To analyze anabolic changes, the authors assessed cell proliferation by measuring [3H] thymidine uptake, and proteoglycan biosynthesis by noting [35S] sulfate incorporation. For catabolic changes, messenger ribonucleic acid (mRNA) expression of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in cartilage and synovium were detected with reverse transcriptase polymerase chain reaction (RT-PCR). Of significance for blocking the development of early OA in chondrocytes was the finding that total proteoglycan synthesis in the HA treatment group was significantly higher than in the controls. At the mRNA level in cartilage and synovium, HA inhibited MMP-3 and TIMP-1 production in the same way in the HA treatment group, while not affecting MMP-1 production. Thus it can be concluded that HA affects cartilage catabolism and anabolism to prevent the progress of OA.

Animals↗
PubMed1999

[Utility of nocturnal oximetry for case finding in patients with suspected sleep apnea syndrome].

OBJECTIVE: Pulse oximeter is a useful screening device for SAS. We studied whether measurement of SaO2 could identify patients with SAS and evaluate the severity of SAS. METHODS: 174 snorers were assessed clinically and then underwent formal PSG and oximetry test at the same time. From the oximetry data, the percentage of time spent at SaO2 below 90% (SIT90%), waking SaO2(H SaO2%), the lowest SaO2(L SaO2%) during sleep, the mean SaO2(M SaO2%) and the number of oxygen desaturation > or = 4% per hour (DI4) were calculated. We also divided 100 cases among them into four groups by AHI, which were G0(AHI < 5), G1(AHI 5-19), G2(AHI 20-39), G3(AHI > or = 40), and evaluated whether the SIT90, ISaO2, MSaO2 and DI4 are different among the four groups. RESULTS: There was an statistically significant correlation (r = 0.91 P < 0.001) between DI4 and AHI. DI4 > or = 5 per hour identified patients with AHI > 5 with a sensitivity of 94%; DI4 > or = 15 per hour identified patients with AHI > 5 with a specificity of 98%, and for patients with AHI > or = 20, the sensitivity was 100%. The SIT90 and DI4 were significantly different among the four groups (P < 0.01). CONCLUSIONS: Oximetry with DI4 < 5 practically excludes clinically significant SAS, and DI4 > or = 15 identified almost all of them. SIT90 and DI4 could be used as parameters in evaluating the severity of SAS.

Circadian Rhythm↗
PubMed1999

[The role of breathing control disorder in the development of carbon dioxide retention in patients with obesity hypoventilation syndrome].

OBJECTIVE: To define the role of breathing control in the pathogenesis of carbon dioxide (CO(2)) retention in patients with obesity hypoventilation syndrome. METHODS: 10 obese obstructive sleep apnea syndrome (OSAS) patients were studied. They were separated according to their waking arterial partial pressure of CO(2) (PaCO(2)), 5 being eucapnic and 5 hypercapnic. Both groups had similar body mass index, apnea hypopnea index and normal lung function. The hypoxic (Delta P(0.1)/Delta SaO(2), Delta V(E)/Delta SaO(2)) and the hypercapnic response (Delta P(0.1)/Delta PaCO(2), Delta V(E)/Delta PaCO(2)) were tested before and during continuous positive airway pressure (CPAP) treatment (at 2, 4, 6 weeks). RESULTS: Compared with the eucapnic patients, all the hypercapnic patients had lower Delta P(0.1)/Delta SaO(2) [(-0.04 +/- 0.02) cmH(2)O% vs (-0.14 +/- 0.03) cmH(2)O%], Delta V(E)/Delta SaO(2) [(-0.17 +/- 0.04) L x min(-1)% vs (-0.34 +/- 0.04) L x min(-1)%], Delta P(0.1)/Delta PaCO(2) [(0.23 +/- 0.1) cmH(2)O/mm Hg vs (0.49 +/- 0.1) cmH(2)O/mm Hg], Delta V(E)/Delta PaCO(2) [(1.32 +/- 0.7) L x min(-1) x mm Hg(-1) vs (2.18 +/- 0.81) L x min(-1) x mm Hg(-1)] and the Delta P(0.1)/Delta SaO(2), Delta V(E)/Delta SaO(2) were also lower than the normal value. After treatment with CPAP, the hypercapnic and the hypoxic response of the hypercapnic patients increased gradually, at about 4 approximately 6 week, both of them increased to the normal range, PaCO(2) showed a complete return to eucapnia, their weight were unchanged. CONCLUSION: The depressed breathing control play an important role in the development of CO(2) retention in OSAS patients, and the disorder in breathing control may be secondary to hypoxia, hypercapnia and sleep disorder related to the OSAS.

Adult↗
PubMed1998

[Molecular biological evidence for the genetic stability of in vivo passaged doxorubicin resistant cell line S-180R].

OBJECTIVE: To assess the genetic stability of doxorubicin resistant sarcoma 180 cell line(S-180R) after in vivo passages. METHODS: Flow cytometry, Southern blot, Northern blot and RT-PCR were used to examine genes and molecules related to drug resistance. RESULTS: The drug-efflux of S-180R was nearly 100-fold as high as that of the parental cells. The ratio of half peak width to peak height was 0.23 as compared to 0.56 measured two years before when the S-180R cell line was initially established. The mdr-1 gene was significantly amplified and transcribed while the transcription of topoisomerase II alpha gene was decreased. However there was no increase in mRNA expression of the multidrug resistance associated protein(MRP). CONCLUSION: Compared with the initially established S-180R, its resistance to doxorubicin is not only maintained but in fact has been increased since in vivo passage for 2 years. The major mechanism is amplification and over-expression of mdr-1 gene, but decreased topoisomerase II alpha also contributes. S-180R is an ideal experimental model for the study of doxorubicin resistance and its reversion.

ATP-Binding Cassette Transporters↗
PubMed1998

[Cloning and expression of subunit genes of pertussis toxin and its immunological evaluation].

OBJECTIVE: To clone the gene encoding pertussis toxin (PT) from Bordetella Pertussis CS strain and five genes encoding subunits of PT, to investigate the possibility of expressing the genes encoding for mature methionyl subunits of PT in insect cell and to evaluate the immunological characteristics of recombinant subunits. METHODS: The genes encoding for PT and its subunits were cloned by PCR and confirmed by restriction enzyme digestion and Southern blot. Using recombinant baculovirus technology, the recombinant subunits were expressed in Sf9 insect cells and analyzed by immunofluorescence assay. The immunological properties of recombinant subunits were analyzed by ELISA. RESULTS: The genes encoding for PT and its subunits were cloned and expressed in Sf9 cells. The level of specific antibodies against nature PT induced by five recombinant subunits polymerized was higher than that unpolymerized and polymerized by four recombinant subunits (without S1) in mice. The results indicate that PT subunits had weak ability to induce specific antibodies against PT, and also anti-nature PT sera had poor recognition to PT subunits. CONCLUSION: The ability of PT to induce specific antibody is conformation dependent of intact PT, and antibody induction domains are located dominantly in S1 subunit of intact PT.

Animals↗
PubMed1998

[Breathing control of patients with obstructive sleep apnea syndrome (OSAS) during sleep].

OBJECTIVE: It is assumed that reduced ventilatory control function during sleep may be one of the mechanisms resulting in obstructive sleep apnea syndrome (OSAS), but the breathing drive has never been measured in patients with OSAS during sleep. METHOD: P0.1, delta P0.1/delta SaO2, delta VE/delta SaO2, delta P0.1/delta PaCO2 and delta VE/delta PaCO2 in sixteen patients with severe OSAS were measured via nasopharyngeal tubes connected with nasal mask to maintain upper airway patent, during wake and NREM I + II, NREM III + IV, REM sleep stages, and the same parameters in eleven normal subjects, non-snorers were also measured, by nasal mask as control. RESULT: (1) During wake: P0.1 in all the OSAS patients was remarkably higher than that of the normal subjects (P < 0.05), but there was no difference in delta VE/delta SaO2, delta P0.1/delta SaO2, delta VE/delta PaCO2 and delta P0.1/delta PaCO2 between the two groups (P > 0.05). (2) The above parameters measured during sleep compared with that measured during wake: In NREM I + II and NREM III + IV, normal subjects showed no significant decrease in P0.1, delta P0.1/delta SaO2, delta P0.1/delta PaCO2 (P > 0.05), but delta VE/delta SaO2 and delta VE/delta PaCO2 decreased significantly (P < 0.05). In REM1 P0.1 maintained the same level as that during wake, but both hypoxic and hypercapnic responses decreased remarkably (P < 0.05). In the OSAS patients, P0.1 decreased during NREM I + II and REM sleep (P < 0.5), but not during NREM III + IV (P > 0.05). delta VE/delta SaO2, delta P0.1/delta SaO2, delta P0.1/delta PaCO2 and delta VE/delta PaCO2 decreased markedly during all sleep stages (P < 0.01). (3) From wake to sleep, delta VE/delta SaO2 decreased by 51.6 +/- 30.4% (Mean +/- SD) in the OSAS patients vs 33.6 +/- 26.0% decreased in the normal subjects; delta VE/delta PaCO2 decreased by 56.9 +/- 25.5% in OSAS vs 40.8 +/- 17.5% in the normal subjects; The hypoxic and hypercapnic responses in OSAS patients decreased much more than those in the normal subjects during sleep (P < 0.05). CONCLUSION: This is the first study to measure the hypoxic and hypercapnic responses successfully in OSAS patients during sleep. It was found that the breathing drive was significantly reduced in sleeping OSAS patients, which may play an important role in the development of OSAS, possibly through the reduced action upon the dilators causing the upper airway in predilection for collapse.

Adult↗
PubMed1998

[Application of capillary non-gel sieving electrophoresis to the analysis of short tandem repeat in phenylalanine hydroxylase gene and gene diagnosis of phenylketonuria].

OBJECTIVE: To establish a sensitive, accurate and reliable method for analysis of short tandem repeat (STR) markers for gene diagnosis, capillary electrophoresis (CE) was used for analysis of a polymorphic tetranucleotide (TCTA)n in intron 3 of the phenylalanine hydroxylase (PAH) gene. METHODS: Capillary non-gel sieving electrophoresis (CNGSE) system was used to analyze PCR products of PAH STR among 61 normal Chinese individuals and 6 phenylketonuria (PKU) families. RESULTS: The PCR fragments that differ 4 bp from each other were well separated by CNGSE. Ten alleles were identified, with a continuous distribution from 224 bp to 260 bp. The largest allele (260 bp) was first detected in Chinese population. The alleles frequencies were calculated and PIC is 0.738. The genotypes of PAH STR of total 80 Chinese people were also analyzed and the heterozygosity is 75%. We used this procedure to PAH gene linkage analysis in 6 PKU families, in which pathogenic gene could be affirmed in 3 families, including one case of prenatal diagnosis. CONCLUSIONS: In comparison with denaturing polyacrylamide gel electrophoresis, CE is an accurate, rapid, automatic and with high resolution analytical tool. CE in combination with PCR is a hopeful technique and might be widely used for gene diagnosis of genetic diseases in the future.

Alleles↗
PubMed1998

[Influence of mannitol additive on DNA separation by capillary non-gel sieving electrophoresis].

Polymer solutions with high concentration were employed as sieving buffer in order to obtain satisfactory separation of smaller DNA fragments with length of less than 1,000 base pairs. The concentrated polymer solution had very high viscosity, which was difficult to be pumped into or out of the capillary. Mannitol additive can enhance the sieving ability of hydroxy-propylmethylcellulose (HPMC) solution in a Tris-Borate-EDTA background electrolyte. With the existence of mannitol, good separation of PGEM-3Zf(+)/Hae III was able to be obtained in a less concentrated HPMC solution with relatively low viscosity. The optimum mass concentration of mannitol was investigated and it was found that 60 g/L mannitol could give the best results. Mannitol chain could be formed through hydrogen bond among mannitol, HPMC and borate. This kind of mannitol chain shaped the network and decreased the pore size, so the separation was greatly enhanced.

Base Sequence↗