Biomedical subjects

L Liu

Publications and source records attributed to L Liu.

At least 577 records · Page 32Linked to original sources

PubMed1999

[Effects of stimulation of dorsal medial area and ventral medial area of nucleus facialis on myoelectric activities of genioglossus and phrenic muscle].

Effects of electrical and chemical stimulation of the dorsal and ventral medial area of nucleus facialis (dMNF and vMNF) on myoelectric activities of genioglossus and phrenic muscle were observed in 44 urethane-anaesthetized and vagotomized rabbits. The results are as follows. (1) Long train electrical stimulation at the dMNF facilitated myoelectric activities of genioglossus and phrenic muscle. (2) Short train electrical stimulation of dMNF, when delivered in the inspiratory phase, caused prolongation of myoelectric activities of genioglossus and phrenic muscle; but when delivered in the expiratory phase, myoelectric activities of genioglossus and phrenic muscle were shortened. (3) Long train electrical stimulation at the vMNF inhibited myoelectric activities of genioglossus and phrenic muscle. (4) Short train electrical stimulation of vMNF caused shortening of myoelectric activities of genioglossus and phrenic muscle, when delivered in the inspiratory phase, but a prolongation when delivered in the expiratory phase. (5) The effects of microinjection of glutamate to dMNF and vMNF were similar to those of electrical stimulation. The above results suggest that both dMNF and vMNF participate in the regulation of the myoelectric activities of genioglossus and the upper airway resistance.

Animals↗

PubMed1999

PCR assay for the inversion causing severe Hemophilia A and its application.

OBJECTIVE: To develop a new technique based on long distance polymerase chain reaction (LD-PCR) to replace Southern blotting method to detect Factor VIII (FVIII) gene inversion leading to severe Hemophilia A (HA) and carrier. METHODS: Four primers P, Q, A&B were designed and synthesized. P&Q is specific for 5' and 3' flanking regions of F8A1 respectively. A&B is specific for 5' and 3' flanking regions of F8A2/F8A3 respectively. LD-PCR with 3 primers and 3 temprature was set up, optimized and used to detect the inversion. RESULTS: The LD-PCR with primers P, Q, A&B, P, Q&B and P, Q&A can be used to detect the gene inversion and discriminate carrier from wild type. A blind analysis of 53 DNA samples from HA families was carried out by the LD-PCR and Southern blotting respectively. Two sets of the results were completely identical. They were 23 cases of inversion, 27 cases of wild type and 3 cases of carriers. The sensitivity and specificity of LD-PCR are both 100%. Three inversion hemizygotes and 4 female carriers were identified from 5 HA families by the LD-PCR technology. CONCLUSIONS: The LD-PCR with primer P, Q&B or P, Q, A&B can be used to detect the gene inversion and the carrier of inversion. Compared with Southern blotting, this technique is simple, rapid, inexpensive, more sensitive, accurate and non-isotopic.

Chromosome Inversion↗

PubMed1999

Ultrasound biomicroscopic study on changes of ocular anterior segment structure after topical application of cycloplegia.

OBJECTIVES: To observe the changes of the ocular anterior segment structure and the relationship between the intraocular pressure (IOP) and these changes after the topical application of cycloplegia using ultrasound biomicroscope (UBM), especially to observe the changes of ciliary body thickness, ciliary process thickness and ciliary process-lens distance. METHODS: The quantitative measurement with UBM and the measurement of IOP were performed before and after the topical application of 2% homatropine solution in 48 normal eyes. The results were statistically analyzed. RESULTS: In the parameters showing the changes of the anterior chamber angle after topical use of 2% homatropine solution, both the trabecular iris angle and the angle opening distance 250 decreased. The iris thickness 1 increased. The anterior chamber became deeper and the iris-lens contact distance became shorter. All these differences were statistically significant (P < 0.05). In the parameters showing the changes of ciliary body, the ciliary body thickness and the ciliary process thickness decreased. The scleral ciliary body angle increased. The iris-zonule distance decreased and the ciliary process-lens distance increased. All these differences were statistically significant (P < 0.05). The IOP increased from 17.63 +/- 3.45 mm Hg to 18.23 +/- 3.53 mm Hg after topical use of 2% homatropine solution, but the difference was not statistically significant (P > 0.05). CONCLUSIONS: After the topical use of cycloplegia, the anterior chamber becomes deeper. The anterior chamber angle becomes narrower, and the ciliary body becomes thinner and moves backward and the ciliary process-lens distance increases. By using UBM the structures of the ocular anterior segment in the living state can be observed and measured quantitatively. The ultrasound biomicroscopic imaging has its advantages in the morphological study of the ocular anterior segment.

Adult↗

PubMed1999

Non-invasive assessment of myocardial risk and infarct area in canine model of myocardial reperfusion by intravenous contrast echocardiography.

OBJECTIVE: To evaluate the newly developed perfluoropropene-filled echo-contrast agent (FCT-188) in non-invasive assessment of risk areas (RA) and infarct areas (IA) with intravenous myocardial contrast echocardiography (MCE) in canine model of ischemia followed by reperfusion. METHODS: Eight chest-opened Beagle dogs with a 90-minute ischemia followed by a 240-minute reperfusion were studied. MCE was performed after a bolus injection of FCT-188 (0.025 ml/kg, i.v.) into a superficial vein of the forelimb at baseline, 20 minutes after occlusion, and 4 h after reperfusion to non-invasively assess the left ventricular myocardium area (LVMA), myocardial ischemic risk area (RA), and infarct area (IA) in a short-axis view of left ventricle. The accuracy of detecting myocardial perfusion with intravenous MCE was further assessed by in vitro myocardial staining of the matched cross-sections. Both RA and IA were expressed as percent of LVMA. RESULTS: LVMA, RA, IA, and IA/RA ratio were accurately assessed by MCE (LVMA: 6.60 cm2 +/- 0.76 cm2; RA: 35.7% +/- 6.68%; IA: 21.0% +/- 13.2%; IA/RA: 60.3% +/- 31.4%; n = 7) as compared with those of the matched cross-section (LVMA: 6.81 cm2 +/- 0.73 cm2, P = 0.062; RA: 35.3% +/- 9.9%, P = 0.84; IA: 25.10% +/- 14.5%, P = 0.07; IA/RA: 68.0% +/- 22.2%, P = 0.28, respectively). There was a significant correlation of MCE-assessed IA/RA ratio and its corresponding pathologically determined finding in vitro (Y = 1.21 x -21.6, r = 0.73, P = 0.015). No significant changes of electrocardiogram (ECG), mean artery pressures (MAP), pulmonary artery pressures (PAP), and pulmonary artery wedge pressures (PAWP) were found between pre- and post-intravenous injection of FCT-188 at each time point. CONCLUSION: These indicate that FCT-188 can be used to assess risk areas and infarct areas accurately and non-invasively with intravenous MCE in the canine model of a 90-minute ischemia followed by a 240-minute reperfusion and might have potential significance for non-invasive assessment of myocardial reperfusion clinically.

Animals↗

PubMed1999

[Gene diagnosis of X linked retinitis pigmentosa by linkage analysis].

OBJECTIVE: To establish a gene diagnosis method for X linked retinitis pigmentosa (XLRP). METHODS: Ten microsatellite markers were selected from the region where the RP2 and RP3 gene may be located at Xp21.1-p11.23. Haplotype analysis for XLRP pedigrees was used to determine the chromosome region which is RP related and whether this region was carried by the individuals we want to detect. RESULTS: The young female who is the RP carrier or the young boy who is the pre-symptom RP patient could be determined this way in 4 XLRP family. CONCLUSION: Haplotype analysis for XLRP Pedigrees is useful.

Adult↗

PubMed1999

[The relationship between ophthalmic nerve lesion in glaucoma and ocular and systemic haemodynamic disturbance].

OBJECTIVE: To explore the relationship between the optic nerve lesion in glaucoma and ocular and systemic haemodynamic disturbance. METHODS: The color Doppler imaging was used to study blood velocity in the ophthalmic, the central retinal and the short posterior ciliary arteries in 34 patients with primary open angle glaucoma, 31 patients with low tension glaucoma and 90 healthy controls. The peak systolic velocity(PSV), the end diastolic velocity (EDV) and resistive index (RI) in each artery were measured, moreover the nailfold microcirculation and blood viscosity in each patient were examined. RESULTS: Compared with the control group, the PSV and EDV of the central retinal arteries were significantly lower while the RI of the central retinal arteries was significantly higher in both POAG and LTG patients. The RI of the short posterior ciliary arteries however was significantly higher in POAG. Nailfold microcirculation shows that some important parameters, including flow pattern, loop surrounding, morphological weighted value, total weighted value and capillary deformity rate in the two glaucoma groups were higher, whereas the flow velocity was lower than in the control group. The plasm viscosity and the whole blood viscosity (low spear) were higher than normal. According to our measurements, the nailfold microcirculation and blood viscosity was worse at the end stage of glaucoma than at early stage. The correlative analysis between measurement results of color doppler imaging and microcirculation and heamorrheology showed that nailfold microcirculation morphological weighted value was negatively correlated with the EDV of the central retinal artery and positively correlated with the RI of the central retinal artery in LTG patients. CONCLUSIONS: The abnormity of ocular haemodynamics and systemic microcirculation and blood viscosity is one important factor of optic nerve damage in glaucoma.

Adolescent↗

PubMed1999

Toxicology of intrahepatic arterial administration of interventional phosphorus-32 glass microspheres to domestic pigs.

OBJECTIVE: To evaluate the toxic response to intrahepatic arterial administration of radioactive phosphorus-32 glass microspheres (32P-GMS) in domestic pigs. METHODS: Through selective catheterization of hepatic artery, 32P-GMS was infused to 5 healthy domestic pigs in a dosage equivalent to the therapeutic dose for human being, and 31P-GMS was infused to other 5 healthy domestic pigs. Two pigs served as the whole course blank controls. One pig from each group was surrendered to euthanasia at week 1, 2, 4, 8 and 16, respectively, and liver biopsies were performed on the rest of pigs at the corresponding time points. Liver tissues from different sites were taken for light and electron microscopy. The ultrastructural histopathological changes were evaluated semiquantitatively. RESULTS: The accumulative amount of 32P-GMS in the target tissue attained more than 90% of the total dose administrated. Histologically, abnormal hepatocytes were easily found at week 1 or 2. At week 4 they were less than at week 1 or 2, and endothelium of the sinuses were damaged prominently. At week 8 they were scarcely seen, and liver tissue recovered gradually. The histological features of liver tissue restored to normal at week 16. Semiquantitative analysis of ultrastructural morphology in the experimental group showed no statistical difference (P > 0.50) between the nuclear abnormality (Nabn) and mitochrondrial variability (Mvar) at week 1 or 2, but revealed prominent difference (P < 0.01, P < 0.001) as compared with those in other groups. In the experimental group the Nabn in tissues showed no significant difference (P > 0.20) between week 8 and week 16. CONCLUSION: 32P-GMS internal irradiation at the dosage equivalent to human therapeutic dosage exerts reversible injury to domestic pig liver tissue, and it takes more than 8 weeks for the injured liver tissue to recover.

Animals↗

PubMed1999

Preliminary studies on tin miners' lung cancer tissue related genes by differential display mRNA.

OBJECTIVE: To study the genes related to tin miners' lung cancer tissue. METHOD: Differential display mRNA. RESULTS: Thirty cDNA fragments which differentially expressed in lung cancer tissues and the same patient's normal lung tissues were discovered. Among these, 16 expressed in lung cancer tissues, not in normal lung tissues; fourteen expressed on the contrary. Six cDNA fragment sequence was determined. Five sequences CG2, CG7, CG8, CA5 and CC6 had less than 75% homology with known sequences in GenBank BLAST, so they were believed to be new sequences which we have recorded in Genbank. Only one fragment coded CG3 had homology up to 95% with human ribosome protein L27a gene. CONCLUSIONS: mRNA differential display provides a unique and powerful experimental system to study differential gene expression in tin miners' lung cancer tissues and the same patient's normal lung tissues. Using the system, differential expression of 30 cDNA fragments was observed. Six of them may be used to study the molecular mechanism of miners' radon-associated lung cancer.

Adenocarcinoma↗

PubMed1999

[Expression patterns of platelet membrane glycoprotein in healthy adults].

OBJECTIVE: To study the expression patterns of 6 kinds of platelet membrane glycoprotein(GP) in resting and activated platelets of healthy adults. METHODS: The molecule numbers of platelet GPIIIa, IIb/IIIa, Ib, IX, V and P-selectin on resting platelets or platelets activated by thrombin receptor activating peptide (TRAP) in 60 healthy adults (male/female = 1/1) were detected by flow cytometry. RESULTS: The expression of GPIIb/IIIa and GPIIIa seemed to decrease with the increase of age in the resting and activated platelets of males. The coefficients of correlation(r) in resting platelets were -0.409 and -0.534 (P < 0.05), respectively; whereas this phenomenon were not found in females. The expression of GPIb was reduced while the expressions of GPIIb/IIIa, IIIa, P-selectin increased after the platelets were activated by TRAP. There was a negative relationship between resting and activated platelets in the expression of P-selectin. The molecule number of GPIb on the surface of resting platelet was about 30,000, the ratio of GPIb to GPV was 3:1. CONCLUSION: It seems that there exists some difference with age and sex in the expression of platelet membrane glycoproteins in healthy persons.

Adult↗

PubMed1999

[P-selectin and tachykinins in bronchial hyperresponsiveness of asthma].

OBJECTIVE: The characteristic feature of asthma is bronchial hyperresponsiveness (BHR). It is due predominately to inflammation of airways. Pathologically, there are inflammatory infiltration, epithelial sloughing and mucosal edema in the bronchi. The objective of this study is to investigate the relationship between BHR and airway inflammation. METHODS: 57 cases of asthma and 22 normal subjects were tested with bronchial reactivity examination and P-selectin, substance P (SP) and vasoactive intestinal peptide (VIP) in plasma. RESULTS: It was found that the bronchial reactivity to inhaled methacholine was positive in 53 of the 57 asthmatic patients (92.98%), while the remaining four were negative (7.02%). Twenty-two normal subjects were all negative with the test of bronchial reactivity. The levels of P-selectin and SP in asthmatics with corticosteroids treatment (n = 27) were higher than those in the control group (P < 0.05), but lower than those in asthmatics treated with aminophylline and salbutamol sulfate (n = 30), (P < 0.01). The concentration of VIP in asthmatics with corticosteroids treatment was significantly higher than that of asthmatics with out corticosteroids treatment (P < 0.01) but lower than that in the control group (P < 0.01). There was positive relationship between bronchial reactivity and P-selectin (r = 0.328, P < 0.05), as well as SP (r = 0.529, P < 0.01) in asthmatics, but negative relationship between bronchial reactivity and VIP (r = -0.419, P < 0.05). CONCLUSION: The increase of P-selectin and SP and decrease of VIP can induce BHR, corticosteroids can reduce levels of P-selectin, SP and enhance the level of VIP, therefore it can improve the reactivity of airway and relieve symptoms.

Adult↗

PubMed1999

[The effects of Xuezhikang on neointimal proliferation and C-myc gene expression after angioplasty in rabbits].

OBJECTIVE: To investigate the effects of Xuezhikang (XZhK) on the neointimal proliferation and C-myc gene expression after angioplasty in rabbits. METHODS: Angioplasty for atherosclerotic stenosis of celiac arteries was performed in 30 male white rabbits after being fed with cholesterol-supplemented diet for 8 weeks, which were then randomized to control group, high-cholesterol group and XZhK group. After 4 weeks, the local vessels were collected for morphological observation. C-myc mRNA level was measured with RT-PCR and C-myc protein with immunohistochemical analysis. RESULTS: Morphological observation showed that the neointimal area in the XZhK group were less than the control group (P < 0.05), and that in control group were less than that in the high-cholesterol group (P < 0.05). The levels of C-myc mRNA measured with RT-PCR and the percentage of C-myc protein positive cell by immunohistochemical analysis were lower in the XZhK group than in the control and high-cholesterol group (P < 0.05), The levels in the latter two groups showed no difference (P > 0.05). CONCLUSION: XZhK can inhibit the neointimal proliferation and the expression of C-myc gene after angioplasty in rabbits.

Angioplasty, Balloon↗

PubMed1999

[Detection of lipoarabinomannan-IgG in cerebrospinal fluid with enzyme-linked immunosorbent assay for diagnosis of tuberculous meningitis].

OBJECTIVE: To ascertain the value of lipoarabinomannan-IgG (LAM-IgG) determination in the diagnosis of tuberculous meningitis. METHODS: LAM-IgG in cerebrospinal fluid was detected with enzyme-linked immunosorbent assay. RESULTS: The positive rate of LAM-IgG in 73 patients with tuberculous meningitis was 51%, 36 control cases were all negative. The specificity was 100%. CONCLUSIONS: Detection of LAM-IgG in cerebrospinal fluid is a useful tool for diagnosis of tuberculous meningitis.

Antibodies, Bacterial↗

PubMed1999

[The extracellular matrix of optic nerve head in normal human adult].

OBJECTIVE: To demonstrate the macromolecular components of extracellular matrix of lamina cribrosa from young human donors. METHODS: Immunoperoxidase (ABC) staining method was used to investigate the distribution of collagen type IV, laminin and fibronectin in the lamina cribrosa of 7 pairs of normal human eyes. RESULTS: There was a large amount of collagen type IV and laminin in the cribrosa plates, but no positive staining of fibronectin in them. The positive staining of fibronectin only existed at the blood vessel region. CONCLUSION: The lamina cribrosa contains a specialized extracellular matrix of the central nerve system made up of plates of material resembling basement membrane.

Adult↗

PubMed1999

[Diagnosis and analysis of cyclodialysis by ultrasound biomicroscopy].

OBJECTIVE: To determine the morphologic changes and their clinical significance of cyclodialysis. METHODS: 173 eyes of 173 patients with cyclodialysis were examined by ultrasound biomicroscopy (UBM) for the morphologic changes, and the measurements of relative parameters were analyzed statistically. RESULTS: The cyclodialysis in all the cases was 360 degree. The characteristic manifestations of cyclodialysis found by UBM were as follows: no echoes between sclera and ciliary body, anterior displacement and rotation of ciliary process and displacement of pars plana toward the centre of eyeball. Superciliary effusion could be observed in some cases. In some patients, the ciliary body may be completely disintegrated from the scleral spur, but the disintegration may be quadrantal instead of 360 degree, resulting in a fistula between anterior chamber and superciliary cavity. The anterior chamber depth of the affected eye (2,115 +/- 589) microm was markedly shallower than that of the normal eye (2,736 +/- 441) microm (t = 4.49, P < 0.001). The shallowing of anterior chamber was caused by the anterior displacement and rotation of ciliary processes and the resulting anterior bulging of the iris root. CONCLUSIONS: UBM can be used to make a correct diagnosis of cyclodialysis irrespective of optic media condition, and can provide evidences for treatment.

Adolescent↗

PubMed1999

[A clinical observation of krypton yellow laser photocoagulation for cystoid macular edema in nonproliferative diabetic retinopathy].

OBJECTIVE: To evaluate the clinical effects of krypton yellow laser photocoagulation for cystoid macular edema (CME) in nonproliferative diabetic retinopathy (NPDR). METHODS: 52 eyes (37 cases) with CME in NPDR were treated with local or grid macular krypton yellow photocoagulation, and according to the course they were divided into two groups: group I ( or= 7 months). The follow-up was 1 year. The visual acuity and the degree of macular edema in various period were analyzed and compared. RESULTS: The mean visual acuity was 0.27 +/- 0.21 before treatment and 0.53 +/- 0.26 after treatment (P < 0.01), 90.4% was increased, 5.8% was stable and 3.8% was decreased. CME disappeared completely in 55.8% of the patients, disappeared partially in 42.3% and stable in 1.9%. In group I the visual acuity was improved in 81.5% of the patients at post-treatment 1 month; at post-treatment 6 months, the visual acuity was increased in 100% of the cases, CME disappeared completely in 70.4% and disappeared partially in 29.6%. In group II, the visual acuity was improved in 20% of the patients at post-treatment 1 month, and at post-treatment 6 months in 88%, CME disappeared completely in 40% and disappeared partially in 56%. The differences in the rate of visual recovery and therapeutic effects between the two groups were statistically significant (P < 0.01). CONCLUSIONS: Krypton yellow laser is prominently effective and selective for CME in NPDR. The effects are related to the course of the disease, and the therapeutic results are better in cases receiving early treatment.

Adult↗

PubMed1999

[Studies on respiratory phase switching effects of Bötzinger complex].

The effects of electrical stimulation of Bötzinger complex (Bot.C) on respiratory rhythm were investigated in 40 urethane anesthetized adult rabbits. The results were as follows. (1) A short train stimulation delivered in the early inspiratory phase produced a transient inhibition of phrenic discharge. The stimulus, when delivered in the mid or late inspiratory phase, could cause a premature termination of the inspiratory phase ("inspiratory off-switch") and a switching to the expiratory phase, which was accompanied with the reduced duration of the consecutive expiratory phase. There was a negative linear correlation between the threshold intensity of inspiratory off-switching and delivery time of stimulation. (2) A short train stimulation delivery in the expiratory phase elicited a transient phrenic discharge. The discharge in the late expiratory phase was followed by a premature onset inspiration. This effect was also dependent on the strength and delivery time of the stimulus. The results suggest that the Bot.C is involved in the central control of respiratory phase-switching.

Animals↗

PubMed1999

[Changes in p50 and oxygen metabolism during mild hypothermia cardiopulmonary bypass].

OBJECTIVE: To study the changes of p50 and oxygen metabolism during mild hypothermia cardiopulmonary bypass, arterial blood lactate(ABL) were measured, arterial and venous blood gas were analysed in 21 patients undergoing cardiac valve replacement. RESULTS: p50, oxygen consumption(VO2), and oxygen extract rate(ERO2) were decreased during hypothermia and increased during rewarming, respectively (P < 0.05 or P < 0.01), while the change of SvO2 was adversed. PvO2 was decreased significantly during rewarming(P < 0.01), and ABL was continuously increased. CONCLUSION: Both reduction in oxygen utilization during hypothermia and relative deficiency of oxygen supply during rewarming cause tissue hypoxia.

Adult↗

PubMed1999

[Preliminary study on chemical changes in the decocting process of radix et rhizoma Rhei].

OBJECTIVE: To understand the chemical changes in the decocting process of Radix et Rhizoma Rhei. METHOD: Comparing the contents of many kinds of anthraquinones in the crude drug, decoction and drug sediments of Radix et Rhizoma Rhei by HPLC. RESULT: The contents of combined and free anthraquinones changed after the crude drug was decocted. CONCLUSION: These changes may be related to the hydrolysis of combined anthraquinones, the decomposition of free anthraquinones, and the inter-transition among anthraquinones.

Anthraquinones↗