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Biomedical subjects

S Xu

Publications and source records attributed to S Xu.

At least 361 records · Page 20Linked to original sources
PubMed1997

[Biomechanical observation on unstable intertrochanteric fracture fixed by 130 degrees angled-plate].

We examined the stability of unstable intertrochanteric fracture fixed by 130 degrees angled-plate biomechanically, and the stress distribution of the plate. The results showed that after 300 times circle-loading test, the fracture stability was destroied. Stress concentration was observed on the plate, which was aggravated by circle-loading test. These confirmed the inproper biomechanical stature of the plate. Referring to the clinical review, we conclude that using angled-plate to fix unstable intertrochanteric fracture hardly yields satisfactory results, at least, early wight-bearing exercise should not be promoted.

Biomechanical Phenomena↗
PubMed1997

[Effects of captopril on the myocardial performances and hemodynamics after cardiac arrest].

UNLABELLED: The effects of cardioplegia and reperfusional blood containing 4.6 mumol/L captopril (CPL) on the myocardial performances and hemodynamics of canine heart under hypothermic extracorporeal circulation were studied. Twenty four mongrel dogs were divided randomly into 3 groups. CONTROL GROUP: Only modified St. Thomas cardioplegia was used. CPL group: St. Thomas cardioplegia containing CPL 4.6 mumol/L was used and the same concentration of captopril in the circulatory blood was established before releasing the cross clamp. CPL + phenylephrine group: The concentration was the same as the CPL group, with an additional dose of phenylephrine (2 micrograms/kg) into the oxygenator and abdominal coarctation. The results revealed that the coronary blood flow and left ventricular contractility and relaxation indices of CPL group were significantly improved than those of the control group, and increasing the systemic and pulmonary vascular resistence had no effect on the cardiac function protected by captopril. It is suggested that captopril could ameliorate the recovery of myocardial performences by inhibitting myocardial and systemic renin-angiotensin system and scavenging free radicals.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

[Changes of 5-HT2A receptor binding on platelet of patients with CAD and the effects of exercise test].

It is known both 5-HT2A receptors of platelet and vascular smooth muscle regulate vascular constriction and platelet aggregation to 5-HT challenge. And that 5-HT-induced hypperreactivity of vascular smooth muscle and platelet were noted in patients with coronary artery disease (CAD). In order to investigate the mechanism of platelet hyperreactivity in cardiovascular disease. Platelet 5-HT2A receptor were measured by specific binding of 3H-ketanserin in patients with CAD (CAD group) and patients with chest pain but without CAD as well as healthy subjects (control group) before and after submaximal treadmill exercise. At the same time the levels of plasma 5-HT were also measured. The results showed: (1) In the resting state, 3H-ketanserin exhibited saturable binding with Bmax of 71.1 +/- 10.1 fmol/mg protein, Kd 1.35 +/- 0.20 nmol/L in control group (n = 8) and with Bmax of 102.1 +/- 22.2 fmol/mg protein, Kd 2.44 +/- 0.66 nmol/L in CAD group (n = 10). Between two groups had no significant difference (P > 0.05). And the specific binding of 2.0 nmol/L 3H-ketanserin and the level of plasma 5-HT in CAD group were higher than those in control group (P < 0.05). (2) After exercise all of the specific binding of 2.0 nmol/L 3H-ketanserin, Bmax of receptor binding and the level of plasma 5-HT were significantly increased in CAD group but not in control group. The above results suggested that the up-regulation of platelet 5-HT2A receptor was involved in the platelet hyperreactivity in CAD. The submaximal treadmill exercise had no significant effect on platelet function in control group, but it could lead to platelet 5-HT2A receptor increment and platelet activation in CAD group. Therefore, these changes of platelet might play a role in the acute myocardial ischemia induced by exercise.

Adult↗
PubMed1997

[Three-dimensional finite element stress analysis of magnetical retaining and bar retaining in overdenture implants].

The purpose of this study was to determine which type of denture retaining implants can produce better biomechanical effect on the bone tissue. Two mechanical models of magnetically retained complete overdenture supported by osseo-integrated implant and bar-retained complete over denture supported by osseo-integrated implant were made. The peak stress in mandibular peri-implant bone tissue of the models were studied under the same loading conditions vertically and horizontally by three-dimensional FEM stress analysis. The results were as follows: (1) Both types of dentures retention can produce significant stress effect on the peri-implant and other regions of the jaw bone and (2) Magnetical retention is more beneficial to maintenance both of peri-implant bone tissue and long-term success of denture supported by osseo-integrated implant than bar retention does.

Dental Implantation, Endosseous↗
PubMed1997

[High-methylprednisolone treatment in acute cervical spinal cord injury without fracture and dislocation].

We compared methylprednisolone (MP), surgical decompression and both in acute cervical spinal cord injury without fracture and dislocation. The study involved 32 acute cervical spinal cord injury without fracture and dislocation. MP was given to 8 cases (high-MP group) within 8 hours after injury. 12 cases (surgical group) underwent surgical decompression (anterior or posterior approach) within 48 hours after injury. 12 cases (combined group) were treated with MP within 8 hour of their injury and surgical decompression within 48 hours after injury. Neurological function was assessed using scores according to international standards for neurological and functional classification of spinal cord injury. The results showed that combined group were more effective than high-MP or surgical group, in the complete or incomplete spinal cord injury, and in motor and sensory. The risk of such complication as gastrointestinal bleeding or delayed wound healing is not significant with using high-MP.

Aged↗
PubMed1997

[Traumatic ascending ischemic injury of the spinal cord].

We report five cases that the paraplegic level showed ascending from the segment of spinal injury upward to the higher level. In T10-11 fracture-dislocation, the paraplegic level ascended gradually to C2-3 in case 1 within 10 days and death due to breathing paralysis. In case 2, the paraplegic level ascended to cervical cord with loss of strength in both arms within 14 days. The remaining 3 cases were Ti2(in 2 cases) and L3(1 case) fracture. Their paraplegic level ascended to T8(2 cases) and T9(1 case). There were lower motor neuron paralysis in all cases. Observation on spinal cord specimen of case 1 showed thrombosis of dorsal vessels at T9-10 segment and multiple thrombosis were found in anterior spinal vessels, central spinal vessels and intramedullar small vessels upward to C3 and downward to S1 segments. The whole cord underwent ischemic necrosis.

Adult↗
PubMed1997

[The development of a CPU controlled COPD recovery training ventilator].

A COPD recovery training ventilator controlled by micro-computer is described. The paper include the design principles of emphasizing on the expiration help and reducing the FRC, stimulating phrenic nerve to strengthen inspiration and to lay up strength, stimulating abdominal muscle or pressing on abdomen to enhance expiration and make diaphragm relaxing thoroughly, four period synchronizing control mode and the hard and soft construction.

Animals↗
PubMed1997

[Purification, serology and detection of grapevine leaf roll virus].

Closterovirus-like particles associated with grapevine leaf roll disease were purified from stem phloem tissue by differential centrifugation and cesium sulphate-sucrose density gradient centrifugation. The particles were between 660-2000 nm long. Most of them were about 1400 nm long and also decorated by the antiserum against GLRV NY-1 isolate. The purified preparation was tested for their serological relatedness in indirect ELISA. The results indicated that these closterovirus-like particles reacted with serotype II, III and IV of GLRV. The antiserum to NY-1 (type III) reacted more strongly than type IV (to VA-4) and type II. (to 1800 nm). In sodium dodecyl sulfate immunodiffusion test, the extract of diseased petiole reacted with serotype III, IV and II. It is possible to be infected by 2 or 3 closterovirus-like particles in China. We have made antiserum to the purified closterovirus-like GLRV and set up a PAS-ELISA to detect GLRV-free grapevine plantelets. We have obtaimed 21 varieties of GLRV-free and GFLV-free grapevine. They shown high quality and quantity in field test.

English Abstract↗
PubMed1997

[The prospective study of the influence of cytomegalovirus (CMV) infection of pregnant women to fetus].

Screening of CMV infection in 450 pregnant women in Shenyang was carried on by ELISA and PCR methods, and CMV infection was detected in 100 of their infants prospectively. The results were 97.11% of pregnant women with past infection, 0.89% with primary infection, 11.11% with recurrent infection, only 2% were susceptible. From 450 pregnant women, there were 3 infants with congenital defects and 3 abortions in active infective group, who were positive for IgM antibody, CMV DNA were positive in heparin peripheral blood, cervical secretion, placenta or amnionic fluid. The fetal infection rate and congenital defect rate in infective group were higher than that in inactive control group. Within 100 maternal-infant pair group, congenitally infected infants were 1.43 times higher in infective group than that in control group (RR = 1.43). Two infants with mental retardations (MDI<70) were born in infective group, but none in control group. In our study, primary infection of early pregnancy was most harmful to fetus, the intrauterine transmission rate was 33.3%. Among nine infected infants born from the infective group, two infants were with CID, and seven were symptomless. CMV screening is important for pregnant women in view of eugenic. When active CMV infection is found in early pregnancy, termination of pregnancy is better considered while CMV detection of amniotic fluid is also positive.

Adult↗
PubMed1997

CAND3: a ubiquitously expressed gene immediately adjacent and in opposite transcriptional orientation to the ATM gene at 11q23.1.

Using a magnetic beads-mediated cDNA selection procedure and a fetal brain expression library, we identified a transcriptional unit within a cosmid positive for the marker D11S384. Pursuit of its full-length cDNA led to the cloning of the third candidate gene (CAND3) we studied in our quest for the ataxia-telangiectasia (A-T) gene, ATM. CAND3 spans approximately 140 kb of genomic DNA and is located immediately centrimeric to ATM, with 544 bp of DNA separating the two genes. CAND3 encodes two ubiquitously expressed transcripts of approximately 5.8 kb and approximately 4.6 kb that are divergently transcribed from a promoter region common to ATM. Nucleotide sequence was determined for one of its alternately spliced transcripts. The predicted protein has 1175 amino acids and is novel in sequence, with only weak homologies to transcriptional factors, nucleoporin protein, and protein kinases, including members of the phosphatidylinositol 3-kinase (PI-3 kinase) family. Although neither homology to ATM nor any mutation of CAND3 in A-T patients has been found, the head-to-head arrangement of CAND3 and ATM, with expression of both housekeeping genes from a common stretch of 544 bp intergenic DNA, suggests a bi-directional promoter possibly for co-regulation of biologically related functions. YACs, BACs, cosmids, and STSs are defined to aid in further study of this gene.

Amino Acid Sequence↗
PubMed1997

Apolipoproteins of HDL can directly mediate binding to the scavenger receptor SR-BI, an HDL receptor that mediates selective lipid uptake.

The class B type I scavenger receptor, SR-BI, binds HDL, mediates selective uptake of HDL cholesteryl esters by cultured cells, and its expression is coordinately regulated with steroidogenesis in several endocrine tissues (adrenal, ovary, testes). SR-BI can also bind LDL and anionic phospholipids, which raised the possibility that HDL apolipoproteins might not participate directly in HDL binding. We have examined the ability of individual human HDL apolipoproteins (apoA-I, apoA-II, and apoC-III) reconstituted into phospholipid/unesterified cholesterol complexes to bind to murine SR-BI (mSR-BI) expressed in stably transfected cultured cells. All three apolipoprotein/phospholipid/unesterified cholesterol complexes specifically associated with mSR-BI expressing cells with high affinity and competed for the binding of HDL, while apolipoprotein-free complexes did not. Furthermore, lipid-free forms of these soluble apolipoproteins also competed for HDL and apolipoprotein/ phospholipid/cholesterol complex association with mSR-BI, but locust high density lipophorin and bovine serum albumin were not effective competitors.Thus, all three of the HDL apolipoproteins (apoA-I, apoA-II, and apoC-III) tested can directly mediate binding to mSR-BI, and this multiligand apolipoprotein receptor may be responsible for at least some of the multilipoprotein and apolipoprotein binding activity previously observed in cells and tissues.

1,2-Dipalmitoylphosphatidylcholine↗