Biomedical subjects

Yan Lu

Publications and source records attributed to Yan Lu.

139 records · Page 8Linked to original sources

PubMed2002

Reversal of secondary hyperparathyroidism by phosphate restriction restores parathyroid calcium-sensing receptor expression and function.

Secondary hyperparathyroidism (secondary HPT), a common disorder in chronic renal failure (CRF) patients, is characterized by hypersecretion of parathyroid hormone (PTH), parathyroid hyperplasia, and decreased expression of the calcium-sensing receptor (CaR). Dietary phosphate loading promotes secondary HPT, and phosphate restriction prevents and arrests secondary HPT in CRF. This study examined the ability of phosphate restriction to restore parathyroid CaR expression and function. Uremic rats fed a 1.2% P diet for 2 weeks developed secondary HPT with down-regulated CaR expression. Continuation on the 1.2% P diet for 2 more weeks worsened the secondary HPT and further decreased CaR, but switching the rats to a 0.2% P diet for 2 weeks normalized PTH, arrested parathyroid hyperplasia, and restored CaR expression to normal. The calcium-PTH relationship was abnormal in uremic rats fed a high phosphate (HP) diet with a right-shifted calcium set point but was corrected by 2 weeks of phosphate restriction. A time course revealed that following the switch to a low phosphate diet, PTH levels were normalized by day 1, and growth was arrested by day 2, but CaR expression was restored between days 7 and 14. We conclude that although phosphate restriction restores CaR expression and function in parathyroid glands of uremic rats, it is a late event and not involved in the arrest of secondary HPT.

Animals↗

PubMed2002

Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities.

Nitrogen contaminant transport, transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat. They were Group A, planting density of 0.0208 plants/cm2, Group B, 0.1042 plants/cm2, and Group C, 0.1415 plants/cm2. The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment. From analysis of wastewater treatment capacity, wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B, 2.6 times for Group A while nitrogen residue was only 7.06%. Hence, wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity, optimal removal ratio and least residue in soil, which was closely related to crop planting density, crop growth status and also background nitrogen quantity in soil.

Agriculture↗

PubMed2002

[Significance of serological test of blood group in nonmyeloablative allogeneic peripheral blood stem cell transplantation of patients with acute leukemia].

The purpose of this study is to explore the clinical significance of RBC blood group serological test in nonmyeloablative allogeneic peripheral blood stem cell transplantation (NAPBSCT) of ABO group incompatibility in 4 patients with acute leukemia. ABO and MN blood group of donors and recipients were determined by hemagglutination test and Rh blood group by Diana Gel phenotype Rh card. The changes of blood group in recipients were observed and implant of donor cells was monitored by short tandem repeat-PCR method. The results showed that in 2 cases of 4 recipients the marrow cells appeared mixed chimera of donor and recipient cells, and blood group changed to donor type in 1 of the 2 cases on 100 days after transplantation. In another 2 cases, the marrow cells appeared mixed chimera without blood group chimera on 154 days after transplantation, and rejection of the transplant occurred in 1 of the 2 cases. The determination of hemagglutinin titer showed that the implant rate of donor cells was lower in the recipients with higher hemagglutinin titer and blood group chimera did not appear, conversely, the implant rate was higher in the recipients with lower titer and blood group chimera appeared early. It is concluded that examination of RBC blood group in NAPB SCT can indirectly reflect effectiveness of transplantation, contribute to decide the intensity of conditioning protocol and immunosuppressive therapy after transplantation, estimate prognosis and guide blood transfusion during transplantation.

Adult↗

PubMed2002

Aloin, cinnamic acid and sophorcarpidine are potent inhibitors of tyrosinase.

OBJECTIVE: To evaluate the effects of aloin, cinnamic acid and 15 other kinds of natural chemicals on the activity of tyrosinase, in order to provide lightening agents in the treatment of hyperpigmentation disorders and cosmetic additives. METHODS: Tyrosinase activity was estimated by measuring the oxidation rate of L-dopa. Inhibition of the enzyme was deduced according to the Lineweaver-Burk plots compared to the control. RESULTS: Cadabine, paeonal, farrerol, evodin, cinnamic acid, aloin and sophorcarpidine had different levels of inhibition of tyrosinase. The inhibitory rates of cinnamic acid (2 mmol/L, 0.5 mmol/L), aloin (2 mmol/L) and the rest were significantly higher than that of hydroquinone (0.5 mmol/L) (P < 0.05). CONCLUSIONS: Tyrosinase activity can be greatly inhibited by cinnamic acid, aloin and sophorcarpidine, of which sophorcarpidine functions as an uncompetitive inhibitor, compared to aloin and cinnamic acid, which are mixed-type inhibitors.

Cinnamates↗

PubMed2002

[Study on the electrophoresis finger-prints of three groups of traditional Chinese drugs].

OBJECTIVE: To identify three groups of traditional Chinese drugs by electrophoresis finger-prints. METHODS: The 3 groups of drugs of different species or varieties were analyzed by protein, peroxidase(POD) isozyme and esterase (ES) isozyme polyacrylamide gel electrophoresis, respectively. And their finger-prints were established. RESULTS: Not less than one kind of electrophoresis finger-prints has significant difference between the drugs of each group, which can be used to distinguish all the species in this group. CONCLUSIONS: Different species even different varieties of traditional Chinese drugs can be identified accurately with proper electrophoresis finger-prints.

Drugs, Chinese Herbal↗

PubMed2002

[Comparison of curative effect between decompression and incision of endolymphytic sac].

OBJECTIVE: We compared the curative effect between endolymphytic sac decompression and incision of endolymphytic sac to explore a simple, effective surgical way with less complication. METHOD: 23 endolymphatic sac decompression and 22 incision of endolymphatic sac were performed routinely under general anesthesia. RESULT: 41 of 45 patients were followed up more than 2 years after the surgical procedure, 21 of which received endolymphatic sac decompression, while others received incision of endolymphatic sac. According to Chinese Meniere disease's diagnosis and curative effect standard evaluation criteria tried out in 1996, 13 got grade A(completely controlled), 4 got grade B (fundamentally controlled), 3 got grade C (partially controlled) while 1 got grade D (not controlled) among 21 patients who received endolymphatic sac decompression. The fully control rate is 61.9%. Among 20 patients who received incision of endolymphatic sac, 12 got grade A (completely controlled), 5 got grade B (fundamentally controlled), 2 got grade C (partially controlled) while 1 got grade D (not controlled). The fully control rate is 60%. CONCLUSION: There is no significant difference between endolymphatic sac decompression and incision of endolymphatic sac in curative effect,but endolymphatic sac decompression is more convenient,safe and has less complication compared with incision of endolymphatic sac. From this,we favor endolymphatic sac decompression in selection of surgical method.

Adult↗

PubMed2002

[Study on the relativity between cultivated varieties and quality of Radix Glehniae].

OBJECTIVE: To study the relation between different cultivated varieties and quality of Radix Glehniae. METHODS: Polysaccharide, imperatorin and extractives in different varieties were detected according to document and Chinese Pharmacopeia. RESULTS: Each content of soluble carbohydrate, rough polysaccharide, total carbohydrate, water extractives and alcohol extractives in Baitiao is significantly higher than that in other two varieties (P < 0. 05). The content of imperatorin is highest in Dahongpao P < 0.05). CONCLUSION: It is more effective for Baitiao to restrain humor immunity,cell immunity and the overgrowth of T and B cells. Dahongpao is dominani as sedative, spasmolytic and abti-asthmatic.

Apiaceae↗

PubMed2000

Expression of Human Soluble CD40 Ligand in Pichia pastoris and Its Effects on Dendritic Cells and Malignant B Cells.

CD40 ligand (CD40L) is a member of the tumor necrosis factor (TNF) superfamily and is expressed primarily on the activated CD4( )T lymphocytes. The CD40 molecule, the cognate receptor of CD40L presents on many immunocytes such as B lymphocytes, dendritic cells (DCs) as well as on some neoplastic cells. Triggering of CD40 through CD40L plays a central role in the initiation and regulation of the human immune response. In order to further investigate the possible biological roles of CD40 signaling triggered by CD40L, we subcloned the DNA fragment encoding the extracellular region of human CD40L into the pSK plasmid. After being sequenced, the target fragment was introduced into the pPICZalphaA plasmid to construct the pPICZalphaA-sCD40L expressing vector which was then transduced into Pichia pastoris GS115 cells by electroporation. The tansformant expressed sCD40L in culture supernatants with a maximum yield of about 35 mg/L. Furthermore, we found that the recombinant human soluble CD40 ligand (rhsCD40L) could effectively induced human peripheral blood monocytes(PBMCs) in vitro in the absence of TNFalpha into dendritic cells (DCs) with the typical morphology and special surface markers of dendritic cells including CD1a, CD80, CD83, and HLA-DR etc. To our surprise, the rhsCD40L also could inhibit directly in vitro proliferation of the CD40-positive multiple myeloma cell line XG-2 and the B lymphoma cell line Daudi significantly at an optimal concentration from 2.5 to 15.0 mg/L, while CD40 negative ovarian carcinoma cell lines, SKB and SKR, were not effected by either high or low concentration of rhsCD40L. Moreover, rhsCD40L had the same effects as CD40L-transfected cell in inducing XG2 cell apoptosis. Our results demonstrated that functional human soluble CD40L could be successfully expressed in the Pichia pastoris system and that the recombinant human soluble CD40L might be a potential immune adjuvant and a new powerful molecule for tumor bio-therapy.

Journal Article↗

PubMed2000

Expression of Human Flt3 Ligand in Pichia pastoris and Its Biological Characteristics.

Flt3 ligand(FL) is a cytokine that stimulates the proliferation and differentiation of hematopoietic stem cells/progenitors. In order to obtain high level of recombinant human soluble FL(rhFL) production, an artificial gene for rhFL was synthesized by using favored genetic codons of the yeast Pichia pastoris. Then the gene was cloned into the vector pPICzalphaA and the resulting construct was introduced into Pichia pastoris for expression. It was found that it was possible to obtain biologically active rhFL with a yield of over 30 mg/L of yeast culture. The rhFL stimulated colony formation from cord blood. rhFL, SCF, GM-CSF and IL-3 are the most promising combination for the in vitro expansion of stem/progenitor cells. It was also showed that rhFL increased the induction of dendritic cells from cord blood in combination with GM-CSF, TNFalpha and IL-4. Interestingly, rhFL stimulated the growth of an endothelial cell line this effect has not been reported before.

Journal Article↗

PubMedDate not supplied

Race and sex differences and contribution of height: a study on bone size in healthy Caucasians and Chinese.

Osteoporosis is characterized by a loss of bone strength, of which bone size (BS) is an important determinant. However, studies on the factors determining BS are relatively few. The present study evaluated the independent effects of height, age, weight, sex, and race on areal BS at the hip and spine, measured by dual-energy X-ray absorptiometry, while focusing on the differential contributions of height to BS across sex, race, and skeletal site. The subjects were aged 40 years or older, including 763 Chinese (384 males and 379 females) from Shanghai, People's Republic of China, and 424 Caucasians (188 males and 236 females) from Omaha, Nebraska. Basically, Caucasians had significantly larger BS than Chinese. After adjusting for height, age, and weight, the Chinese had similar spine BS, but significantly larger intertrochanter BS in both sexes and larger total hip BS in females compared with Caucasians. Males had significantly larger BS than females before and after adjustment in both ethnic groups. The effects of age, weight, and race varied, depending on skeletal site. As expected, height had major effects on BS variation in both sexes and races. Height tended to account for larger BS variation at the spine than at the hip (except for Chinese females), and larger BS variation in Caucasians than in Chinese of the same sex (except for the trochanter in females). We conclude that height is a major predictor for BS, and its contributions vary across sex, race, and skeletal site.

Absorptiometry, Photon↗

PubMedDate not supplied

Hamstring graft technique for stabilization of canine cranial cruciate ligament deficient stifles.

OBJECTIVE: To investigate the harvest and application of hamstring grafts for canine cranial cruciate ligament (CrCL) reconstruction. STUDY DESIGN: Experimental study. ANIMALS: Four adult female hounds, weighing 26.3 +/- 1.6 kg (mean +/- SEM). METHODS-One stifle in each dog was randomly chosen for hamstring graft CrCL reconstruction after native CrCL transection. Arthroscopy was performed to evaluate graft integrity at 12 weeks. Gait analysis and stifle radiographs were performed preoperatively and up to 52 weeks after graft placement. Dogs were killed 12 (n = 2) or 52 weeks (n = 2) after CrCL reconstruction. Tissues were evaluated grossly and with light and confocal laser microscopy. RESULTS: Hamstring grafts were intact in all stifles at 12 weeks (n = 4) and 52 weeks (n = 2). Grossly, there was no osteoarthritis in stifles at 12 weeks and only chondrophytes along the trochlear ridges at 52 weeks. Minimal radiographic evidence of osteoarthritis developed in stifles with grafts during the study. Lameness in limbs with grafts resolved by 52 weeks. Graft tissue was highly vascular, ligamentized, and undergoing active remodeling at 12 weeks. Fifty-two weeks after graft placement, intraarticular graft tissue was well vascularized, mature, and encapsulated by synovium, and graft-bone interfaces were characterized by Sharpey's fiber insertions. There was no evidence of graft necrosis using confocal laser microscopy at either time point. CONCLUSIONS: The hamstring graft technique may be a viable method of canine CrCL reconstruction. CLINICAL RELEVANCE: Hamstring grafts may be an alternative technique for canine CrCL reconstruction. Further study is needed before clinical application.

Animals↗

PubMedDate not supplied

Thermal chondroplasty of chondromalacic human cartilage. An ex vivo comparison of bipolar and monopolar radiofrequency devices.

We compared the effects of treatment with bipolar and monopolar radiofrequency energy on 30 osteochondral sections harvested from 22 patients with spontaneously occurring chondromalacia who were undergoing knee arthroplasty. Specimens with chondromalacia grades 2 or 3 were randomly assigned to one of two bipolar or one monopolar treatment groups. All samples were marked and mounted on a jig to allow simulation of an arthroscopic surgical procedure with a flow rate of 100 ml/min of a balanced electrolyte solution at 22 degrees C. Under arthroscopic visualization, the designated area was treated until smooth, and the total treatment time was recorded. There was no difference in patients' ages, chondromalacia grade, or cartilage thickness among groups. Significant chondrocyte death, as determined by cell viability staining with confocal laser microscopy, was observed with each group. The bipolar devices produced significantly greater depths of chondrocyte death (2228 +/- 1003 microm and 2810 +/- 517 microm) than did the monopolar device (737 +/- 391 microm). The bipolar devices caused cell death to subchondral bone significantly more often (13 of 20 specimens) than did the monopolar device (0 of 10 specimens). Caution should be used in treating fibrillated cartilage with radiofrequency energy, particularly with the bipolar devices tested.

Aged↗

PubMedDate not supplied

Lavage solution temperature influences depth of chondrocyte death and surface contouring during thermal chondroplasty with temperature-controlled monopolar radiofrequency energy.

BACKGROUND: Although radiofrequency energy can smooth and contour cartilage surface, it has deleterious effects on chondrocyte viability. HYPOTHESIS: Monopolar thermal chondroplasty in a 37 degrees C lavage solution, as compared with a 22 degrees lavage solution, will reduce chondrocyte death and result in greater smoothing of the articular cartilage surface. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen chondromalacic samples from patients undergoing total knee arthroplasty were divided into two groups: 22 degrees C and 37 degrees C lavage solution. Each sample was divided into two equal parts and half of each group was treated for 10 seconds and the other half for 15 seconds. RESULTS: Confocal laser microscopy demonstrated that the depth of chondrocyte death in the 37 degrees C lavage solution group was significantly less (range, 200 to 340 microm) than that in the 22 degrees C solution group for both 10- and 15-second treatment times. Scanning electron microscopy demonstrated that the cartilage surface in the 37 degrees C lavage solution group was smoother than that in the 22 degrees C solution group for the 10-second treatment time. Energy delivery power in the 37 degrees C lavage solution group was significantly lower than in the 22 degrees C solution group for both treatment times. CONCLUSIONS: Thermal chondroplasty with 37 degrees C lavage solution resulted in less depth of chondrocyte death and produced smoother surfaces than with 22 degrees C solution for 10 seconds of treatment. CLINICAL RELEVANCE: Less chondrocyte death would permit increased use of thermal chondroplasty.

Aged↗