Biomedical subjects

N Li

Publications and source records attributed to N Li.

At least 199 records · Page 11Linked to original sources

PubMed2000

[Molecular cloning and analysing of porcine obese cDNA].

Obese gene (ob) is a novel gene cloned recently. The product of ob gene Leptin is an important signal reflecting body fat mass and controlling body weight. In this study the complete nucleotide sequences of porcine ob cDNA were identified, and the homology with ob genes from other species was also compared. The porcine fat cDNA was constructed based on lambda Uni-ZAP system. The primers designed on the consensus region of human and mouse ob gene were employed to perform PCR-screening of the cDNA library, and a 366 bp DNA fragment amplified from total RNA of pig fat cells was used to confirm positives as a hybridization probe. The complete ob cDNA with 3277 bp in length was cloned and sequenced. The nucleotide sequences of ob genes between different species were very conservative. The overall identity of ob nucleotide sequences was 88.5% between pig and human, 84.7% between pig and mouse. The homology of ob amino acid sequences was 86.0% between pig and human. 83.4% between pig and mouse. The result of RT-PCR for transcripts detection of pig ob gene indicate that ob gene was expressed not only mainly in adipose tissue but also slightly in other tissues such as kidney, liver, spleen, heart and muscle, which imply that expression nature of pig ob gene is different from that of human and mouse ob gene.

Animals↗

PubMed2000

[The genetic effect of estrogen receptor(ESR) on litter size traits in pig].

Litter size is one of the most important economic traits in pig production, and the more piglet numbers per litter is capable to increase pork production and bring more economic profit for pig industry. ESR (estrogen receptor) gene has been determined to be one of the major genes affecting phenotype of litter size without any genetic negative correlation to growth and carcass traits. An optimized standard PCR-RFLP protocol is employed to type 262 sows from 5 different breeds in ESR loci, and then with the computation based on linear model ESR gene is confirmed to be a major locus significantly associated with litter size (P < 0.001). The genetic effect of ESR gene is quite large in these breeds, especially in these Chinese pig population. The sows of beneficial homozygote BB produce 1.40-3.37 total number born/litter and 0.63-3.58 number born alive/litter more than the sows of non-beneficial homozygote AA do. The information found in the present study is very important and could be utilized as DNA marker for improvement of reproduction trait in practice of pig breeding.

Animals↗

PubMed2000

[Reconstruction of the mandible and soft tissue defects with the osteomyocutaneous free fibula flap].

OBJECTIVE: In order to ascertain a material that is ideal both for reconstruction of the composite mandibular defects and for osseointegrated implantation. METHODS: Fifteen osteomyocutaneous fibula flaps were transferred for reconstruction of the mandible and surrounding soft tissues. The characters of the blood supply of the flap, the operation course, the relation of the fibula and dental implants were observed. RESULTS: The osteomyocutaneous fibula flap was supplied by double vessels. The blood supply was reliable even after the fibula was cut into several segments. Periosteal circulation was its main blood supply. The postoperative contour and function of the mandibular region were good. The flap also favours dental implants and denture. CONCLUSION: The osteomyocutaneous fibula flap was the ideal material to reconstruct the defects of mandible and surrounding soft tissues.

Adult↗

PubMed2000

Astragalus mongholicus and Angelica sinensis compound alleviates nephrotic hyperlipidemia in rats.

OBJECTIVE: To investigate the mechanism of lipid-lowering effect of the Astragalus mongholicus and Angelica sinensis compound (A&A) on nephrotic hyperlipidemia in rats. METHODS: Rats with nephrotic syndrome from accelerated nephrotoxic serum nephritis were used. They were divided into two groups: A&A treatment group and nephrotic control group. Normal rats were used as a normal control group. Serum lipids, serum lipoprotein lipase (LPL) and lecithin-cholesterol acyltransferase (LCAT) were assayed biochemically and enzymatically. mRNAs of hepatic hydroxy-methyl glutaryl-CoA reductase (HMG-CoA-R) and low-density lipoprotein receptor (LDL-R) were assessed by Northern blot. RESULTS: In nephrotic control group hyperlipidemia was found. The activities of serum LPL and LCAT were low. Hepatic HMG-CoA-R mRNA increased temporarily at the early stage while LDL-R mRNA decreased gradually. In A&A treatment group, serum total cholesterol (TC), triglyceride (TG), low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL) were significantly lower than those in nephrotic control group. There was no change in the amount of hepatic HMG-CoA-R mRNA, but hepatic LDL-R mRNA and activities of serum LPL and LCAT increased significantly. CONCLUSIONS: A&A alleviates hyperlipidemia considerably in nephrotic rats. A&A improves disorders of lipid metabolism perhaps through up-regulating the expression of hepatic LDL-R gene and through increasing the activities of serum LPL and LCAT.

Angelica sinensis↗

PubMed2000

Effects of platelet activating factor antagonist (BN50739) on gut mucosal injury in acute severe pancreatitis in pigs.

OBJECTIVE: To study the role of platelet activating factor (PAF) in the pathogenesis of intestinal mucosal injury and endotoxin/bacterial translocation in acute severe pancreatitis (ASP) in pigs. METHODS: ASP was induced by intraductal injection of a mixture of sodium taurocholate and trypsin. BN50739, a specific antagonist of PAF, was given 30 min prior to the induction of ASP. Mucosal blood flow, mucosal myeloperoxidase (MPO) and malondialdehyde (MDA) were determined. Intestinal injury was observed microscopically. Portal blood endotoxin levels and the bacterial counts in the portal blood, intestinal lymph nodes and the pancreas were determined. RESULTS: Prior antagonism of PAF by BN50739 reduced intestinal injury, increased intestinal mucosal blood flow, and reduced blood levels of endotoxin and bacterial counts in the portal blood, mesenteric lymph nodes and pancreas. CONCLUSIONS: Intestinal mucosal injury developed in ASP. PAF is responsible for the injury. Antagonism of PAF by BN50739 can improve intestinal microcirculation and reduce the severity of intestinal mucosal injury, which may decrease endotoxin/bacterial translocation.

Acute Disease↗

PubMed2000

[The correlation analysis between frequency of micronucleated cells of exfoliated oral mucosa cells and oral mucosa cells in different grading of oral leukoplakia lesions].

OBJECTIVE: To provide evidence for using micronucleated cells of exfoliated oral mucosa cells in diagnosis and treatment of oral leukoplakias and chemopreventive studies of oral cancer. METHODS: Micronuclei of exfoliated oral mucosa cells and oral mucosa cells in 119 patients comprising 59 simple hyperplasia, 32 mild and moderate oral leukoplakia and 28 severe oral leukoplakia and oral squamous carcinoma by Feulgen stain method were examined, and micronuclei of exfoliated oral mucosa cells in 100 normal persons were also examined. RESULTS: Frequency of micronucleated cells of exfoliated oral mucosa cells in oral leukoplakia lesions was higher than that of normal persons. Frequency of micronucleated cells of exfoliated oral mucosa cells had a positive correlation with oral leukoplakia lesions(r = 0.9997, P < 0.001) and with frequency of micronucleated cells of oral mucosa cells (P < 0.001). CONCLUSIONS: Frequency of micronucleated cells of exfoliated oral mucosa cells are useful markers to the clinician to predict oral leukoplakia behaviour and prognosis and substitute for frequency of micronucleated cells of oral mucosa cells as intermediate endpoint in chemopreventive trials.

Adult↗

PubMed2000

[Value of Gallium-67 scanning in differentiation of malignant and benign tumor in oral and maxillofacial area].

OBJECTIVE: To evaluate Gallium-67 scanning in differentiation of malignant and benign tumor in oral and maxillofacial region. METHODS: 41 patients with tumors in the oral and maxillofacial region were undergone Gallium-67 scanning. The results were correlated with the final pathologic diagnosis. RESULTS: Twenty out of 21 patients who had malignant tumors showed positive Gallium-67 scanning images (95.23%); three of 20 patients who had benign tumors also demonstrated positive results (15.00%). There was a significant difference between these two groups (P < 0.001). CONCLUSIONS: Gallium-67 scanning is a useful adjunct tool for differentiation of malignant and benign tumors in oral and maxillofacial region.

Adult↗

PubMed2000

Rehabilitative therapy of short bowel syndrome: experimental study and clinical trial.

OBJECTIVES: To investigate the effect of growth hormone on proliferative activity of the residual small intestinal mucosa after massive small intestinal resection and to evaluate the clinical efficacy of bowel rehabilitative therapy for short bowel syndrome. METHODS: Small intestinal mucosa proliferative activity were compared in rats from control group (sham operation), short bowel group (80% small bowel resection) and growth hormone treatment group (80% small bowel resection + growth hormone 1 U x kg(-1) x d(-1) for 28 days) with the aid of histology image analysis, flow cytometric assay, immunohistochemistry analysis and RT-PCR assay. The nutritional status, D-xylose absorption and stool nitrogen output were observed in 9 consecutive parenteral nutrition dependent patients with short bowel syndrome after intestinal rehabilitative therapy (growth hormone 8 - 12 U x kg(-1) x d(-1) im + glutamine 0.6 g x kg(-1) x d(-1) iv + special diet) for 21 continuous days. RESULTS: Growth hormone administration significantly increased rat small intestinal mucosal villous height, mucosal thickness, proliferative index, and the expression of proliferating cell nuclear antigen and c-jun mRNA. Rehabilitative therapy increased the body weight, serum total protein and album in concentrations in patients. Their D-xylose absorption indices increased and fecal nitrogen losses decreased. Follow-up data showed that 6 of the 9 patients sustained on enteral nutrition. CONCLUSION: Growth hormone enhances the proliferative activity of the mucosal epithelium and bowel rehabilitative therapy may benefit the patients with short bowel syndrome.

Adolescent↗

PubMed2000

[Improvement of protein metabolism by glutamine-enriched TPN and growth hormone in recipients of rat small bowel transplantation].

OBJECTIVE: To observe the effect of glutamine-enriched TPN and recombinant human growth hormone (rhGH)on protein metabolism of recipient of rat small bowel transplantation. METHODS: Twenty four recipients of rat allogeneic heterotopic small bowel transplantation (SD-->Wistar rat) were divided into 4 groups randomly according to the presence or absence of glutamine or rhGH in TPN regimen. Cyclosporine A (CsA) was used as the immunosuppressant. The changes of body weight, nitrogen balance, urinary 3-methyl histidine excretion and plasma albumin level during 14 days after transplantation were observed. RESULTS: Applications of glutamine-enriched TPN or rhGH decreased the postoperative catabolism of protein of recipients. They promoted protein synthesis and positive nitrogen balance so as to minimize the loss of body weight and correct hypoalbuminemia. They were synergistic to other. CONCLUSIONS: Glutamine-enriched TPN and rhGH can promote the protein metabolism of rat small bowel transplantation recipients effectively with the use of CsA, so as to improve the recovery of general condition. Their combination may have the synergistic effect.

Animals↗

PubMed2000

[CT guided percutaneous fine needle aspiration for early diagnosis of pancreatic infection after acute necrotizing pancreatitis].

OBJECTIVE: To assess CT-guided percutaneous fine needle aspiration (FNA) for early diagnosis of pancreatic infection after acute necrotizing pancreatitis. METHODS: CT-guided percutaneous FNA was employed to diagnose pancreatic infection after acute necrotizing pancreatitis in 14 patients. The aspirates were smeared, cultured and subjected polymerase to chain reaction (PCR) for detecting bacteria. RESULTS: Ten patients were diagnosed as having pancreatic infection and 4 non-pancreatic infection. FNA was totally performed for 15 times: left retroperitoneal route for 12 times, left and right retroperitoneal route for one time, and transperitoneal route for two times. The sensitivity of smear, PCR, culture to diagnose pancreatic infection was 7/10, 9/10, 10/10, respectively. Their specificity was 4/4, and the time for obtaining the results was 30 minutes, 4 hours, 3 days respectively. CONCLUSIONS: Retroperitoneal approach can be used for most patients with acute necrotizing pancreatitis when performing CT guided-percutaneous FNA. PCR of aspirates is a rapid and accurate method to diagnose pancreatic infection.

Adult↗

PubMed2000

[Modified sternal turnover with pedicle of abdominal rectus muscle for pectus excavatum].

OBJECTIVE: To assess surgical correction for children with pectus excavatum. METHOD: Modified sternal turnover operation with rectus abdominalis pedicle was performed on 20 children with pectus excavatum since 1987. RESULTS: The patients were successfully corrected and no recurrence was seen during 6 to 36 months after operation. Human bone density examination showed same results in some patients before and six months after operation. CONCLUSION: Modified sternal turnover operation has the following advantages: easy to operate; less bleeding; better blood supply to the turned sternum; rapid postoperative recovery; satisfied correction of deformity and no recurrence. It should be widely used clinically.

Child↗

PubMed2000

[Studies on intercellular communication of rabbit lens epithelial cells in vitro].

OBJECTIVE: To investigate the intercellular communication in rabbit lens epithelial cells and effect of dexamethasone and heparin on it. METHODS: Rabbit lens epithelial cells were cultured and exposed to different concentrations of dexamethasone (10, 100, 300 mg/L), heparin (1 x 10(5), 2 x 10(5), 4 x 10(5) U/L) for 48 hours at 37 degrees C. The fluorescence redistribution after photobleaching (FRAP) was used for the analysis. The mean fluorescence recovery rate (MFRR, %/min) of the cells labelled with 6-carboxy fluorescein diacetate (CFDA) after photobleaching was measured with laser scanning cytometry ACAS Ultima. RESULTS: MFRR (%/min) of the cells after exposure to dexamethasone was 0.375 +/- 0.236 in the control group, 0.491 +/- 0.239 in the group of dexamethasone 10 mg/L, 0.996 +/- 0.447 in the group of dexamethasone 100 mg/L, 0.984 +/- 0.379 in the group of dexamethasone 300 mg/L, respectively (F = 26.07, P < 0.05). The MFRR after exposure of heparin was 0.375 +/- 0.236 in the control group, 0.694 +/- 0.491 in the group of heparin 1 x 10(5) U/L, 1.097 +/- 0.504 in the group of heparin 2 x 10(5) U/L, 1.082 +/- 0.501 in the group of heparin 4 x 10(5) U/L, respectively (F = 19.01, P < 0.05). CONCLUSION: It is discovered that there is intercellular communication in rabbit lens epithelial cells with FRAP analysis. Dexamethasone and heparin can enhance the intercellular communication of rabbit lens epithelial cells in dose dependent manner.

Animals↗

PubMed2000

[Influence of the administrators of family planning on the spread of norplant in countryside of Sichuan].

The purpose of the study was to understand the family planning administrators' knowledge of Norplant and their fluence on the spread of Norplant in countryside of Sichuan. 156 administratoras were surveyed. It was found that most of the administrators worked hard on education, propagation, organization and management of using Norplant, and they recognized the contraceptive efficacy of Norplant. However, the educational level of the administrators was generally low. They were short of the training on Norplant related knowledge(training rate was only 36.5%). The degree of the users' satisfaction and the administrators' knowledge on Norplant varied between areas. The result indicated that the basic quality of the administrators and their knowledge of Norplant were influences on the spread of Norplant in the countryside of Sichuan. Soit is very important to improve the basic quality and knowledge of the administrators of family planning.

Adolescent↗

PubMed2000

[Thyroglossal duct cyst(fistula) operation and recurrence prophylasis].

OBJECTIVE: To explore what leads to recurrent thyroglossal duct cyst (TGDC) following operation and how to improve the operation efficiency. METHOD: 32 patients with TGDC (including 8 recurrent cases) were performed operation for the second time. The cases who had infective signs received anti-inflammatory treatment prior to operation. Judge the relationship between thyroglossal duct cyst and hyoid bone before managing hyoid bone. The methylene blue was injected into TGDC for following up. Resect the small branches according to Sistruk procedure under the operation microscope. The residue underwent marsupiatization, electrocoagulation or radio frequency according to finger palpation. RESULT: 32 cases were successful with the operation and did not show any signs of recurrence after one-year following up. CONCLUSION: The recurrence of TDGC may be perfectly prevented as long as comprehensive treatment is carefully performed during the operation.

Adolescent↗

PubMed1999

NMDA and AMPA glutamate receptor subtypes in the thoracic spinal cord in lean and obese-diabetic ob/ob mice.

Quantitative autoradiography was used to characterise the binding of selective radiolabelled antagonists for the N-methyl-D-aspartate (NMDA) receptor and the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor in the dorsal, intermediate and ventral subregions of the grey matter of the upper thoracic spinal cord in male and female lean and obese-diabetic (ob/ob) mice. The density of binding sites for both receptor subtypes was greater in diabetic mice, in all three subregions of the grey matter, than the corresponding subregions in the lean mice. The affinity of the binding site for the NMDA antagonist was significantly higher in obese mice than lean mice, consistent with the presence of two subpopulations of NMDA receptors with different ligand binding affinities in obese mice. The increase in expression of the glutamate receptor subtypes, and altered ligand affinity for the NMDA receptor subtype in the obese mice may be causally involved in the peripheral neuropathies which can accompany diabetes mellitus.

Animals↗

PubMed1999

Chemicals in diesel exhaust particles generate reactive oxygen radicals and induce apoptosis in macrophages.

There is increasing evidence that particulate air pollutants, such as diesel exhaust particles (DEP), potentiate chronic inflammatory processes as well as acute symptomatic responses in the respiratory tract. The mechanisms of action as well as the cellular targets for DEP remain to be elucidated. We show in this paper that the phagocytosis of DEP by primary alveolar macrophages or macrophage cell lines, RAW 264.7 and THP-1, leads to the induction of apoptosis through generation of reactive oxygen radicals (ROR). This oxidative stress initiates two caspase cascades and a series of cellular events, including loss of surface membrane asymmetry and DNA damage. The apoptotic effect on macrophages is cell specific, because DEP did not induce similar effects in nonphagocytic cells. DEP that had their organic constituents extracted were no longer able to induce apoptosis or generate ROR. The organic extracts were, however, able to induce apoptosis. DEP chemicals also induced the activation of stress-activated protein kinases, which play a role in cellular apoptotic pathways. The injurious effects of native particles or DEP extracts on macrophages could be reversed by the antioxidant, N-acetyl-cysteine. Taken together, these data suggest that organic compounds contained in DEP may exert acute toxic effects via the generation of ROR in macrophages.

Acetylcysteine↗

PubMed1999

Characterization of genes encoding two manganese peroxidases from the lignin-degrading fungus Dichomitus squalens(1).

Genes encoding two manganese peroxidases from the white-rot basidiomycete Dichomitus squalens were cloned and sequenced. The mnp1 and mnp2 genes encode mature proteins of 369 and 365 amino acids, respectively. The amino acids involved in peroxidase function, those forming the Mn(II) binding site, and those forming the five disulfide bonds in other Mn peroxidases are conserved in these sequences. Both predicted D. squalens proteins contain multiple acidic residues in their C-terminal sequences, which may be involved in additional metal binding. Both genes contain seven small introns, the locations of which align with each other. The promoters of both D. squalens genes contain putative AP-2 sites, which may be involved in their regulation by nutrient nitrogen. Southern blot analysis of genomic PCR fragments suggests that these sequences represent separate genes rather than allelic variants.

Amino Acid Sequence↗

PubMed1999

[Effects of tea on DMBA-induced oral carcinogenesis in hamsters].

The preventive effects of green tea, tea pigments and mixed tea (a composite of whole water extract from green tea, tea polyphenols, and tea pigments) on 7, 12-dimethylbenz(a) anthracene(DMBA)-induced oral carcinogenesis in golden Syrian hamsters were studied. The hamsters were divided into five groups. i.e. the positive control group(the right buccal pouches of animal was topically treated with 0.5% DMBA in acetone three times per week for 15 weeks), three tea treated groups(1.5% green tea, 0.1% tea pigments and 0.5% mixed tea as the sole source of drinking water from two weeks before starting the DMBA treatment to the end of the experiment) and the negative control group(acetone applied topically). The results showed that in the 1.5% green tea, 0.1% tea pigments and 0.5% mixed tea groups, the inhibitory rates of the average number of tumor per hamster were 42.6%, 50.8% and 67.2% respectively, and the mean tumor burdens were 79% 89% and 95% respectively, compared with the positive control group. In the three tea groups, the frequency of micronucleated cells, the number of silver-stained nucleolar organizer regions (AgNOR), labeling index of proliferating cell nuclear antigen(PCNA) and the level of epidermal growth factor receptor(EGFR) expression in the oral mucosa cells were also less than those in the positive control group. These results clearly indicated that the mixed tea could effectively inhibit DMBA-induced oral carcinogenesis in hamsters. The mixed tea was more effective than green tea or tea pigments in this animal model. Protection of DNA from damage by carcinogen and suppression of cell proliferation was considered as important mechanisms of the anticarcinogenic effects of the mixed tea preparations.

9,10-Dimethyl-1,2-benzanthracene↗