Biomedical subjects

H Li

Publications and source records attributed to H Li.

At least 721 records · Page 40Linked to original sources

PubMed2000

[Genotyping of hepatitis C virus and homology analysis of its core gene sequences isolated from different geological regions].

OBJECTIVE: To study the structure of its genotypes and gene variation of hepatitis C virus (HCV) isolated from different geological regions. METHODS: Serum specimens were collected from patients with HCV infection of Henan and Hebei Provinces of China, as well as of Sweden and Germany. HCV RNA in their serum was detected by retro-transcription polymerase chain reaction (RT-PCR) and genotyped. The core gene of 11 HCV isolates were sequenced and their homology was analyzed for different geographic regions with software. RESULTS: Structure of HCV genotypes, isolated from two provinces of China, and from Sweden and Germany, was not identical. The homology of their core gene sequences of the same HCV genotype isolated from the same region was higher than that from different regions, and subtypes 1b and 2a were found in serum collected from China and subtypes 1a, 2c and 3a in serum from Sweden and Germany. CONCLUSION: Structure of HCV genotypes associated with their geographic distribution and difference in sequences of the same HCV genotype also associated with their geographic regions.

Base Sequence↗

PubMed2000

[The sifnificance and characteristics of the internal distribution of Staphylococcal enterotoxin B in burned rats with sepsis].

OBJECTIVE: To investigate the role of staphylococcal enterotoxin B (SEB) in the development of postburn staphylococcus aureus sepsis. METHODS: Rats inflicted with 20% TBSA III degree scald followed by Staphylococcus aureus sepsis were used as the experimental subjects. The distribution of SEB in the vital organs such as the heart, liver, lungs, kidneys and plasma was observed with concomitant serial measurement of the relative organ functional indices. RESULTS: The plasma SEB content increased transiently in the early stage of sepsis (P < 0.01) and then fell to near that of control group. The SEB contents in the heart, liver, lungs and kidneys increased evidently 2 hours after staphylococcus aureus challenging (P < 0.01) and continued to increase afterwards. The functions of multiple organs were impaired obviously at 24 postburn hours, and the function impairment was aggravated by S. aureus challenge. The degree of organ injury of liver and kidneys correlated positively with tissue content of SEB (P < 0.05 similar 0.01). CONCLUSIONS: Staphylococcal enterotoxin B might play a role in the development of MODS induced by postburn sepsis.

Animals↗

PubMed2000

[A canine model of brain edema established in the early postburn stage].

OBJECTIVE: To establish a canine model of brain edema in the early stage of severe burn. METHODS: Mongrel dogs were inflicted by napalm with 50% TBSA III degree burn. The dogs were randomized into normal control (C), burn (B), burn with balanced salt solution (S) and burn with glucose (G) groups. The macropathological, histopathological and ultrastructural changes of brain tissue and brain water (%) were examined at 6, 12, 18 and 24 postburn hours (PBH), respectively, with simultaneous evaluation of blood brain barrier by (99) TC -- ECD. RESULTS: Pathological evidence of brain edema exhibited at as early as 6 PBH in B, S and G groups, which included cellular swelling of partial endothelia and pericapillary astrocytes, and ischemic necrosis of endothelia, neurons and axons to varying degrees. All the changes exhibited more and more obvious with the elapse of postburn time. The brain water content in each burn group, especially in G group at 24 PBH, was more than that in C group. It was indicated by nuclide imaging that there appeared gradual increasing of the concentration of (99) TC -- ECD in brain tissue in B and C groups since 6 PBH. CONCLUSION: This model was established for the convenience of burn scholars to study the pathogenesis and management of postburn brain edema.

Animals↗

PubMed2000

[The impact of hepatitis B virus infected patients or donors on the outcome of hematopoietic stem cell transplantation].

OBJECTIVE: To investigate the impact of recipients and/or donors infected with hepatitis B on the outcome of hematopoietic stem cells transplantation (HSCT). METHODS: We analyzed retrospectively the transplantation outcome in 26 of 164 hematological diseases patients who and whose donors were infected with hepatitis prior to transplantation. RESULTS: (1) Three of the 26 patients developed VOD after HSCT, the incidence (11.5%) is significant higher than that in patients and donors who did not infected with HBV (P < 0.05). (2) Two of 5 patients transfused hematopoietic stem cells from HBsAg + donors developed hepatitis B. (3) Four patients with allogeneic stem cell transplantation developed hepatic failure (HF) which occurred during cyclosporin (CsA) being tapered off or withdrawal. The incidence of HF in patients and/or donors infected with HBV (15.4%) is obviously higher than that in patients and donors who did not (0.08%, P < 0.01). (4) In 4 patients with HbeAg +, 2 patients died of HF after allogeneic HSCT, the other 2 patients survived after autologous HSCT. CONCLUSION: Donors and recipients infected with hepatitis B are not contraindication of HSCT, but patients with allogeneic HSCT are in danger to develop LF during CsA being tapered off or withdrawal.

Adolescent↗

PubMed2000

[A report of two Chinese familial Budd-Chiari syndrome].

OBJECTIVE: To investigate the etiology of two Chinese familial Budd-Chiari syndrome (BCS). METHOD: Four patients with familial BCS (from A and B families), and the other 41 family members were detected by angiography, ultrasound Dopler, etiology analysis and Factor V Leiden (FvL) mutation analysis. RESULT: Four BCS patients were proved by angiography, 2 by ultra sound Dopler in family A. Ten members in family A were varicosis in low extremeties. FvL mutation was detected in 4 of 6 patients and 2 normal family members. A II(2), A III(7, 11, 15,) B II(10) and B III(5) had FvL mutation. The FvL mutations were compatible with Mendel hereditary law. CONCLUSION: FvL mutation may be one of main risk factors and varicosis in low extremeties may be another risk factors for familial BCS.

Adolescent↗

PubMed2000

[Effect of shenkang injection on transforming growth factor-beta messenger ribonucleic acid of LLC-PK1 renal tubular epithelial cells].

OBJECTIVE: To study the effect of Shenkang injection (SKI) on the transforming growth factor (TGF)-beta mRNA of LLC-PK1 renal tubular epithelial cells. METHODS: Using reverse transcriptase-polymerase chain reaction (RT-PCR) and Northern Blot to observe the effect of SKI on the TGF-beta mRNA of LLC-PK1 renal tubular epithelial cells, with control group treated with the injection of Rheum officinale extraction. RESULTS: SKI showed the inhibition of TGF-beta mRNA expression of renal tubular epithelial cells, which is dose-dependent and was more obvious than that of the Rheum extractive injection with equal dose of drug. CONCLUSION: The mechanism of delaying chronic renal failure with SKI is achieved by down regulating TGF-beta mRNA expression of renal tubular cells.

Animals↗

PubMed2000

[Antitumor activity of the lysates prepared from anti-CD3 antibody activated killer cells].

This study was directed at the antitumor activity of the lysates prepared from CD3McAb activated killer cells. We separated the peripheral blood monocytes(PBMC) from normal adults. The PBMC were induced by monoclonal antibody specific for CD3(CD3McAb) and activated by rIL-2. The CD3McAb-activated killer cells (CD3AK) were smashed by ultrasonic wave, along with frozen and thawed three times, then the lysates were obtained by centrifugation. The lysates were tested for antitumor activity in vivo and in vitro. The results revealed that the inhibition rate of the lysates that acted on mice solid tumor hepatoma 22(H22) was 68.20% and the killing activity of the lysates on K562 and Raji were 83.32%, and 66.83% respectively. The results of this experiment suggested that the lysates prepared from CD3McAb-activated killer cells is one of probable agents that might apply to biotherapy for tumors.

Animals↗

PubMed2000

[The study on the anti-osteoporosis effect of clodronate in ovariectomized rats].

To evaluate the anti-osteoporosis effect of clodronate in ovariectomized rats, 44 female Wistar rats, aged 8 months, were divided randomly into 4 groups: the SHAM group (subjected to sham operation); the OVX group (subjected to bilateral ovariectomy); the E3 group (subjected to bilateral ovariectomy and treated after surgery with nilestriol 1 mg/kg BW by gavage once a week for 12 weeks), and the clodronate group (subjected to bilateral ovariectomy and treated after surgery with clodronate 5 mg/kg BW by subcutaneous injection twice a week for 12 weeks). All the animals were sacrificed 12 weeks after the operation. The blood and urine samples were collected for determination of biochemical indices. The humeri and tibiae were prepared for determination of net weight, ash weight, calcium and phosphorus content, bone density, as well as bone histopathology and histomorphometry. The left femora were processed for bone anti-curve power. The results showed that as compared with the SHAM group, the net weight, ash weight, calcium content, density and anti-curve power of bones, te trabecular bone volume and thickness were all significantly reduced in the OVS group, while its osteoblast index, osteoclast index and urine hydroxyproline content were obviously close to normal levels. The data indicates that both clodronate and E3 can effectively prevent bone loss in ovariectomized rats.

Animals↗

PubMed2000

[Cloning of mouse endostatin and primary analysis on its biological activity].

The mouse endostatin cDNA was cloned by the total RNA of Chinese Kunming mouse liver as template with RT-PCR. The results of sequencing showed one base pair difference. The ctg was replaced by gtg(L22545 in GenBank) at position 278 base pair, causing the encoded amino acid from reported Val to Leu in this experiment. This new endostatin cDNA was registered in GenBank with an accession number of AF257775. The recombinant eukaryotic expression plasmid pSecTag2-ES was then constructed and transfected into COS-7 cells for transient expression. The results of testing by Western blotting showed an expression fragment in supernatants of pSecTag2-ES transfected COS-7 cells at 48 and 72 hours of transfection. Cultured HUVECs were used to detect the biological effect of supernatants in pSecTag2-ES transfected COS-7 after 48 hours of transfection. 3H incorporation assay showed an obvious inhibition of endothelial cell prolifetation. The results demonstrated primary that the cloned endostatin cDNA had biological activity.

Angiogenesis Inhibitors↗

PubMed2000

[A treatment combined Chinese with Western medicine for microcirculation diseases in tongue].

OBJECTIVE: Glossodynia is a common oral disease. The purpose of the investigation is to analyse the mechanism of microcirculation disorder in glossodynia, and find a new effective treatment. METHODS: 18 cases with microcirculation disorder in tongue were studied by histopathology, hemorrheology and nail microcirculation, treated by intravenous injection of angelica for promoting blood circulation and removing blood stasis. RESULTS: Hyper-viscosity of blood was found in this group of patients. Abnormal micro-vessels were observed in microcirculation examination, though vasculitis wasn't detected in tongue tissue. CONCLUSION: Microcirculation disorder may play an important role in the cause of glossodynia. For elderly patients, cardiovascular and mental diseases should be considered. According to the theory of the blood stasis in chinese medicine, these studies show that a treatment combined chinese with western medicine can be applied for the patients, and injection of angelica can improve microcirculation.

Aged↗

PubMed2000

[Study of accuracy of one-piece casted and laser welded bridges].

OBJECTIVE: To assess whether laser welded bridge be fit for the clinical usage, this study compares the accuracy of laser welded multi-unit bridges with one-piece casted bridges. METHODS: A precise stainless mold which was 20 mm length composed of two abutments (one premolar and one molar) and one pontic (two missed teeth) was made. 5 wax patterns of four-unit FPD frame-works in one-piece casting based on the mold were made. After that, they were invested with inner (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. The other 5 wax patterns of four-unit FPD frameworks were invested and casted in two halves. Each couple of frameworks were ultra-sonic washed in distilled water and inserted to the standard metal FPD mold accurately. Laser welding machine (DL-2002) was used to weld each couple of frameworks at 305V, 20 ms. Both groups of specimens were tested on their mesiodistal span dimensions and the diameters of alloy crowns. Then they were inserted to their original stainless mold, where the marginal fitness was examined. RESULTS: 1. The one-piece casted fixed multi-unit bridge couldn't be inserted to abutments completely because of distortion, while the laser welded bridge could be inserted to abutments completely. The average marginal opening of laser welded bridges was about 74 microns and conformed to clinical standard of fitness. 2. Mesiodistal dimensions of one-piece casted bridges at the inner, bottom and top margins were 19.5600 +/- 0.3877 mm, 41.2206 +/- 0.4140 mm, 41.0598 +/- 0.3379 mm respectively; while those of laser welded bridges were 20.2950 +/- 0.1191 mm, 41.9625 +/- 0.0788 mm, 42.0584 +/- 0.1089 mm, which were obviously close to metal abutments (P < 0.05). 3. The alloy crowns' diameters of one-piece casted bridges were examined as following, the premolar: phi IJ = 9.8386 +/- 0.0567 mm, phi LK = 9.9596 +/- 0.0548 mm, the molar: phi EF = 11.7948 +/- 0.0252 mm, phi HG = 11.9412 +/- 0.0763 mm; The alloy crowns' diameters of laser bridges were as following, the premolar: phi IJ = 9.7927 +/- 0.0636 mm, phi LK = 9.9438 +/- 0.0726 mm, the molar: phi EF = 11.8287 +/- 0.0863 mm, phi HG = 11.8893 +/- 0.1049 mm. There was no significant difference between the two groups (P < 0.05). CONCLUSION: Laser welding greatly improve the fitness of multi-unit fixed bridges.

Dental Abutments↗

PubMed2000

[Stress-corrosion test of laser welded ceramic alloys].

OBJECTIVE: The corrosion properties of dental material are very critical. This study is to investigate the corrosion properties of laser welded basemetalalloys. METHODS: The precise stainless rod molds had been made in size of phi 3 mm x 4 mm, with which 20 wax patterns were made. They were invested with inner investment (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. All casted alloy rods were ultra-sonic washed in distilled water. Every two rods were contacted longitudinally by a special welding jig. Laser welding machine (DL-2002) was used to weld them at 305 V, 20 ms. The specimens were divided into 2 groups as following: 1. The group of stress-corrosion: 5 laser welded samples were subjected to the stress-corrosion test under 261.44 MPa in the 37 degrees C artificial saliva for 3 months in a special stress-corrosion test jig. After that, the ultimate tensile strength (UTS) was tested, the surface microcrack at the fusion zone (FZ), the heat affecting zone (HAZ) and the interface zone was observed with SEM (ARMY-1845, USA), the elements were also analyzed with EPMA (ARMY-1845, USA) at the fusion zone (FZ), the parent metal zone and the interface zone. 2. The other 5 laser welded samples were made as the controlled group. No special treatment were done to them, and the UTS was also tested, the surface of the micro crack and the elements at the FZ, the HAZ, parent metal zone and the interface zone were observed and analyzed with SEM, EPMA as well. RESULTS: The study showed us that the UTS of the stress-corrosion group was 502.48 +/- 12.49 MPa, while that of the controlled group was 446.05 +/- 82.50 MPa, there was no significant difference (P > 0.05). There was no microcrack on any sample's surface at the FZ, the HAZ and the interface zone. The main elements of the FZ were Ni(56.63%), Cr(19.36%), Nb (6.57%), Si(6.01%), Al(0.32%) and Mo(11.11%), while the elements of the parent metal zone were Ni(60.77%), Cr (20.59%), Nb(5.03%), Si(3.95%), Al(0.37%) and Mo(9.29%) respectively. CONCLUSION: The results suggest that the corrosion properties of laser welded alloys are excellent.

Corrosion↗

PubMed2000

[The effect of intra-articular injection of sodium hyaluronate and prednisolone on rabbits' temporomandibular joints].

OBJECTIVE: To evaluate the different effects of sodium hyaluronate and prednisolone on the surface of rabbits' temporomandibular joints. METHODS: 20 juvenile Japanese large ear rabbits were divided into 5 groups, including one control group and the other 4 experimental groups. In these groups, half of their right inferior cavity of temporomandibular joints were injected with sodium hyaluronate(25 mg/ml, 0.1 ml), while others were injected with prednisolone(1%, 0.1 ml), then the rabbits were killed on the 1st, 3rd, 7th, and 14th days after injection. The specimens were evaluated by scanning electron microscope (SEM) to compare the different effects on the inferior superfacial structure of the articular disc and the surface of the condyle. RESULTS: Prednisolone could change the uniform distribution of the agglutinating substance on the inferior superfacial of the articular disc and the surface of the condyle. In the 1st-day and the 3rd-day groups, the agglutinating substance decreased in some areas and gathered in other areas. In the 7 th-day group, the distribution of the agglutinating substance on the inferior superfacial of the articular disc and the surface of the condyle were more regular than that of the 1st-day and the 3rd-day groups. In the 14th-day group, the distribution of the agglutinating substance were almost as the same as that of the control group. But sodium hyaluronate didn't change the uniform distribution of the agglutinating substance in every group. CONCLUSION: Prednisolone can change the uniform distribution of the agglutinating substance on the inferior superfacial of the articular disc and the surface of the condyle, while sodium hyaluronate don't have this effect.

Animals↗

PubMed2000

[The experimental study on inside-out vein graft for repairing inferior alveolar nerve defect in the rabbit].

OBJECTIVE: This study describes a modification of the vein graft technique inside-out vein graft, creates an autogenous vein conduct with the collagen-rich and Schwann cells exposed to regenerating axons. To compare regeneration of inferior alveolar nerves through two conduits: inside-out vein graft and the standard vein graft. METHODS: 18 adult white rabbits were selected and vena facialises of both sides were harvested. Turned the right vena facialis into inside-out vein and used to bridge an 8 mm defect created in the right inferior alveolar nerve. An 8 mm defect of the left inferior alveolar nerve was bridged by the standard vein graft. After rabbits sacrificed at 8, 14 and 20 weeks, the regenerating nerve cables were harvested from the conduits and performed histologic study. At 20 weeks, performed also electrophysiologic studies and statistical analysis of conductive velocities and histological results. RESULTS: Regenerating nerves connected with proximal and distal nerve stumps on both sides postoperation 8 weeks, a number of regenerating nerve fibers and thickness of axon were gradually increasing. At 20 weeks regenerating nerve on the inside-out vein graft side showed superior function results--faster conduction velocities (P < 0.05) and distinct histological results--much more axon counts (P < 0.05) and thicker mylin sheaths (P < 0.05) compared with contralateral standard vein graft. CONCLUSION: The adventitial surface of vein promotes nerve regeneration by an environment with collagen-rich and Schwann cells. The inside-out vein graft is an original way to repair inferior alveolar nerve.

Animals↗

PubMed2000

[Clinical study of effects of submaxillary transcutaneous electrical stimulation of genioglossus on obstructive sleep apnea syndrome].

OBJECTIVE: To investigate the effect of submaxillary transcutaneous electric stimulation of genioglossus on obstructive sleep apnea syndrome (OSAS). METHOD: Nineteen patients (male) with OSAS were diagnosed by polysomnography previously. Fixed the provocative locus of genioglossus and its controlling nerve with local anatomy. Estimated obstructive level of pharyngeal cavity by observing muller's maneuver under fiberolaryngoscope. Determined the effects of electric stimulation on different levels of narrow pharyngeal cavity with control study method. RESULT: The effect of electrical stimulation was different in different narrow level. The best effect was found on the obstruction of retrotongue-base-pharynx level, data of breath disorder (P < 0.05), oxygen saturation (P < 0.05) and clinical symptoms were significantly improved. The data were partly improved on multilevel obstructions of retrotongue-base-pharynx or above, no improvement was found on the obstruction of retrotongue-base-pharynx level. Dormant index was not worse. CONCLUSION: Submaxillary electrical stimulation is effective to the treatment of OSAS and its curative effect perhaps has a close relationship with obstructive level of with upper-airway. Further research on the mechanism showed that stimulating upper-airway dilating muscle which formed mainly by genioglossus could push the tongue ahead and effectively open pharyngeal cavity. Maybe it is a reason that the best effect took place on the retrotongue-base-pharynx level. Sleep was not affected by electrical stimulation.

Adult↗

PubMed2000

[Effect of vasostomy on expression of Bcl-2 and Bax gene in rat spermatogenic cells].

The objective of this study was to explore the change of Bcl-2 and Bax gene expression in rat spermatogneic cells after vasostomy. A rat model with vasoligation and vasostomy was set up and then used for detecting the protein expression of Bcl-2 and Bax gene at 4, 8, 12, 16 weeks after vasostomy by means of immunohistochemistry. Sixty rats were randomly distributed into three groups named vasoligation group (VG), vasostomy group(VOG) and sham-operation group(SOG) respectively. The results showed that the Bcl-2 protein expression in VOG group increased gradually and came to be significantly higher than that in VG group 8 weeks after vasostomy, and it's level was the same as that in SOG group at the 12th week. The bax protein expressions in VG and VOG groups were significantly higher than that in SOG group, but there was no difference between VOG and VG groups. In conclusion, the change of Bcl-2 protein expression observed in this study is indicative of the anti-apoptosis function of Bcl-2 gene in both the status of being vasoligated and vasostomized, whereas the consistent Bax protein expression before and often the repatency of the vas suggests further researches into its effect on apoptosis of spermatogenic cells.

Animals↗

PubMed2000

[Extension of life-span of normal human fibroblasts by reconstitution of telomerase activity].

Most of normal human somatic cells can divide only a finite number of times and inevitably become senescent. Telomerase is an enzyme that imparts replicative immortality by maintaining the length of the telomeres when expressed in reproductive and cancer cells. Cells that are mortal do not express the telomerase. Recently it was reported that the life-span of the normal human cells could be successfully extended by introduction of telomerase into these cells. We have found, in the previous work, that fibroblasts exhibited an osteogentic potential, and therefore, can be considered as a type of "seed cells" in tissue engineering for bone repairing and reconstruction. But this potential was impaired by the limitation in life-span and proliferative capacity of the normal fibroblasts. In the present work, plasmid pGRN145 bearing a cDNA insert of human telomerase reverse transcriptase (hTERT) was introduced into the fibroblasts with osteogenic potential by electroporation. The stable hTERT+ fibroblast clones was established and cultured for long-term in a medium containing hygromycin-B. The exogenous hTERT mRNA expression and telomerase activity were detected. The hTERT+ fibroblasts showed shorter population doubling time and no beta-galactosidase stain, which indicated a stronger proliferative capacity and fewer signs of cell senescence, compared to their hTERT- counterpart. These evidenced that the life-span of hTERT+ fibroblasts was extended. The assays for DNA euploidy by flow cytometry and chromosome karyotype by cytogenetic technique showed no signs of heteroploidy, providing the data for cell carcinogenesis and utilization safety. The results of the present study suggested that the introduction of hTERT could make the life-span of normal fibroblast extended without causing their malignant transformation, and such type of "longevous" fibroblasts might be clinically useful in tissue engineering for bone repairing and reconstruction.

Cells, Cultured↗

PubMed2000

[Study on production of poly-beta-hydroxybutyrate by recombinant strain VG1(pTU14)].

Cloning and expression of Vitreoscilla hemoglobin gene (vgb) and lambda phage lytic genes (S-RRz) in production of Poly-beta-hydroxybutyrate(PHB) was studied in different Escherichia coli hosts such as E. coliJM105, E. coliJM109 and VG1. In the recombinant strains, VG1(pTU14) was a superior one which simultaneously contained three exogenes including vgb, S-RRz and PHB biosynthesis genes(phbCAB). The experimental results showed that after 82 hours fed-batch cult ure in LBG medium in shaking flask, cell concentration of VG1(pTU14) could reach 25.9 g/L, which was the highest PHB production ever reported, and till 52 h PHB content could be higher than 95%. Additionally, inducible cell lysis was also attained successfully in recombinant VG1(pTU14) accompanying with its high cell density culture. Therefore, VG1(pTU14) is a novel potential strain with promising prospect in industrial production of PHB.

Bacterial Proteins↗