Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

At least 487 records · Page 27Linked to original sources

PubMed2000

The circadian rhythm of blood pressure and the effect of salt intake in salt-sensitive subjects.

OBJECTIVE: To investigate the effect of salt intake on the circadian rhythm of blood pressure and the characteristics of ambulatory blood pressure (ABP) in salt-sensitive (SS) subjects. METHODS: Twenty-three normotensive subjects and forty-three patients with essential hypertension were included in this study. Salt sensitivity was determined with a chronic dietary salt loading test and an acute venous saline loading test, respectively. 24-hour ABP measurements were performed twice in normotensive subjects when they were on a high salt diet and when they had a low salt diet. Blood and urine samples were collected for measurement of plasma norepinephrine concentration (PNE), plasma renin activity (PRA), angiotensin II, aldosterone, erythrocyte sodium content and urinary sodium excretion. 24-hour ABP readings were also obtained in patients with essential hypertension when antihypertensive drugs were discontinued for at least 2 weeks. RESULTS: High salt intake attenuated the circadian rhythm of blood pressure in SS normotensive subjects, and the nocturnal decline in blood pressure was smaller in SS patients with essential hypertension than in salt-resistant (SR) patients. The level of PNE was higher and the suppression of PRA was smaller in SS subjects than in SR subjects when they had a high salt diet, and the urinary sodium excretion decreased and the erythrocyte sodium content increased significantly in SS subjects on high salt intake. CONCLUSIONS: High salt intake caused an abnormal circadian rhythm of blood pressure in SS subjects. The blunted nocturnal decline in blood pressure may be a characteristics of SS patients with essential hypertension.

Adult↗

PubMed2000

An experimental study of endovascular brachytherapy using liquid 32P filled balloon catheter.

OBJECTIVE: To observe the effect of endovascular brachytherapy on the prevention of restenosis after interveneional therapy and to investigate its possible mechanisms. METHODS: In the balloon-injuried rabbit model, pathological sections of iliac arteries were observed and the changes of vascular histomorphology were estimated by computer analysis of photomicrograms. Using immunohistochemical techniques, proliferating cell nuclear antigen (PCNA) was quantified to assess the proliferation of vascular smooth muscle cells. RESULTS: After rabbit iliac arteries were injured by balloon overstretch angioplasty, neointima were shown to be less proliferative in the irradiated group than in the control group, from PCNA scores. The formation of neointima was suppressed with the external elastic laminar area increasing and without the luminal area decreasing in the irradiation group. CONCLUSION: Endovascular brachytherapy using a liquid 32P filled balloon catheter system could prevent restenosis possibly by inhibiting the formation of neointima and improving positive vascular remodeling.

Animals↗

PubMed2000

Change of apoptotic status in the human colorectal adenoma-carcinoma sequences and its correlation with carcinogenesis and prognosis.

OBJECTIVE: To assess apoptotic status during the development of colorectal cancer and its prognostic value. METHODS: The apoptotic frequency of 168 fresh adenocarcinoma specimens and primary cultured cells at 2, 12, 24 and 48 hours (9 normal mucosa, 4 adenomas and 9 adenocarcinomas) were measured by flow cytometry (FCM). Apoptotic indices (AI) in situ for 25 adenomas and 77 adenocarcinomas were visualized by TdT-mediated dUTP nick end labeling (TUNEL), Ki-s5 labeling indices (KI), bcl-2, bax, waf1 and p53 were immunostained with ABC method. RESULTS: The culture-related apoptosis at 24-48 hours in vitro was obviously decreased in cultured tumor cells when compared with mucosa cells. Spontaneous apoptosis in situ occurred more frequently in tumor with aneuploid type at late stage. There was positive relationship between apoptosis and proliferative activity, determined by both TUNEL and FCM methods. The well-differentiated or early stage lesions with intensive bcl-2/bax expression were significantly more likely to have low AI. p53 accumulation and waf1 depression were mainly related to KI, whereas bax and waf1 overexpression led to a comparatively higher AI/KI ratio. bcl-2 and KI were found to be independent risk factors. CONCLUSIONS: The data suggest that the depressed susceptibility to inductive apoptosis may contribute to the initial phase of tumorigenesis, and spontaneous apoptosis in vivo may serve as a marker of tumor progression. The bcl-2 and KI may be valuable in predicting prognosis in colorectal cancer.

Adenocarcinoma↗

PubMed2000

Chinese-made electrolytic detachable coil in the embolization of a dog aneurysmal model.

OBJECTIVE: To develop a Chinese-made electrolytic detachable coil (CEDC) that would allow patients to enjoy the benefit of electrolytic detachable coil without having to rely on the expensive Guglielmi detachable coil (GDC), and to test the safety and efficiency of CEDC. METHODS: Radiopacity of the marker of the CEDC was tested. The anti-strain force of coils and connection points were measured. In vitro and in vivo electrolyses were conducted. We produced 21 aneurysm models including lateral, bifurcation, and terminal aneurysm models, and embolized 18 models with CEDC. RESULTS: Radiopacity of the marker was satisfactory. Anti-strain of the coil and the connection point have shown the safety and efficiency of CEDC. Electrolysis in vitro and vivo, was similar to that of GDC. 83% of the aneurysm models were completely occluded. Coils were found to induce thrombosis in the aneurysm cavity, and could lead to a new endothelium over the entrance of the aneurysm, with organized tissue replacing thrombosis in 2 months. CONCLUSIONS: CEDC is as efficient and safe as GDC. The marker, the ability to induce thrombosis inside the sac and the growth of new endothelium over the orifice are very satisfactory.

Animals↗

PubMed2000

[Regulation of the expression and function of glucose transporter-1 by TGF-beta 1 and high glucose in mesangial cells].

OBJECTIVE: To study the effects of high glucose and transforming growth factor-beta 1 (TGF-beta 1) on the expression and function of glucose transporter-1 (GLUT1) in mouse mesangial cells. METHODS: Cultured mouse mesangial cells were used. The expression of GLUT1 mRNA was detected by Northern Blot; glucose uptake and its kinetics were determined with a 2-Deoxy-[3H]-D-glucose uptake assay. RESULTS: Mesangial cells exposed to enriched glucose medium (20 mmol/L) for 72 hours demonstrated a decrease in both GLUT1 mRNA and Vmax for uptake of the glucose analog, 2-deoxy-D-glucose (2DOG), as compared to mesangial cells cultured in physiologic glucose concentrations (5.5 mmol/L). In contrast, hypertonic mannitol had no effect on GLUT1 mRNA levels. TGF-beta 1 treatment for 10 hours stimulated 2DOG uptake, both in 5.5 mmol/L and 20 mmol/L glucose medium, by approximately 4.28-fold in a dose-dependent manner (2 ng/ml maximum). Kinetic analysis of 2DOG uptake revealed an increase in Vmax and a decrease in Km in the presence of TGF-beta 1. TGF-beta 1 also up-regulated the expression of GLUT1 mRNA in mesangial cells. The addition of anti-TGF-beta neutralizing antibody (30 micrograms/ml) in mesangial cells cultured in enriched glucose medium (20 mmol/L) led to a 40% decrease in 2DOG uptake. CONCLUSIONS: The expression of GLUT1 can be suppressed by exposure of mesangial cells to high glucose medium, which may serve as a protective mechanism against possible adverse effects of excessive glucose flux into cells. TGF-beta 1 stimulates glucose uptake by enhancing the expression and function of GLUT1 in mesangial cells. This effect is independent of the glucose milieu in the cultured medium.

Animals↗

PubMed2000

[Treatment of nonunion in childhood by allogeneic decalcified bone graft].

OBJECTIVE: To investigate the effect of allogeneic decalcified bone graft in the treatment of nonunion in children. METHODS: From April 1990 to September 1997, 17 children with nonunion were adopted in this study. Among them, there were 10 boys and 7 girls, the age ranged from 2 to 13 years. The allogeneic decalcified bone graft taken from fresh corpse by aseptic manipulation were used to repair 3 cases of congenital nonunion and 14 cases of acquired nonunion. RESULTS: All cases were followed up 2 to 9 years after operation, 9 cases were cured successfully and 7 cases were cured after twice operations. One case of congenital pseudoarthrosis of the tibia was operated twice and there were callus grown half years after the second operation, but reoccurred after one year. Although there were 1.5 cm to 3 cm shortening deformity of extremity including another 2 cases of congenital pseudoarthrosis of the tibia and 5 cases of nonunion caused by chronic osteomyelitis, the function of joint was normal. CONCLUSION: Treatment of nonunion in children by allogeneic decalcified bone graft is a valuable technique in clinical practice. It is characterised by high capacity of osteoinduction, low antigenicity, rapid bony union, plentiful source of bone graft and convenient utilization.

Adolescent↗

PubMed2000

[Evaluation of exercise performance and quality of life after lung volume reduction surgery for severe emphysema].

OBJECTIVE: To evaluate grade of dyspnea, exercise performance and quality of life pre and post-lung volume reduction surgery in patients with severe emphysema. METHODS: Serial measurement of lung function, cardiopulmonary exercise test and 6-minute walk distance, and the dyspnea grade assessment by modified dyspnea scale of English Medical Research Council and quality of life by Notting-ham Health Profile were all done before and at 3, 6, 12 months after surgery. RESULTS: FVC, FEV1, MVV increased (P < 0.01) and RV, TLC, RV/TLC decreased at 3, 6, 12 months after surgery (P < 0.01), WATT, TET, VO2max, VO2max/HR, VEmax, VTmax, 6MWD were all improved (P < 0.01), and the dyspnea grade was declined as well as the NHP score(P < 0.01 or < 0.05). CONCLUSION: Lung volume reduction surgery in patients with severe emphysema may improve patient's exercise performance and quality of life.

Evaluation Studies as Topic↗

PubMed2000

[Induction of fluoride-resistant mutant of S. mutans and the measurement of its acidogenesis in vitro].

OBJECTIVE: To induce fluoride-resistant mutant of S. mutans in vitro and find out the differences of cariogenicity between them. METHODS: Fluoride-resistant strain Ingbritt-FR was obtained by subculturing S. mutans Ingbritt to TSA and TSB containing different concentrations of fluoride. Lactic production and terminal pH of media were measured by gas chromatography method. RESULTS: 1. The stable fluoride-resistant mutant of S. mutans Ingbritt had been induced successfully in vitro; 2. Lactic production of Ingbritt-FR was significantly more than its parent strain at various initial pH values with 0.5 and 5.0 mmol/L fluoride whereas when no fluoride existed, there were two situations: the acid production was more than S. mutans Ingbritt at initial pH above 5.0 while the result was opposite when pH was 5.0 and below. CONCLUSION: The fluoride-resistant strain Ingbritt-FR had a stronger cariogenic potential than its parent strain S. mutans Ingbritt in physiological plaques.

Dose-Response Relationship, Drug↗

PubMed2000

[Effect of acupuncture on level of monoamines and activity of adenosine triphosphatase in lateral hypothalamic area of obese rats].

OBJECTIVE: To study the mechanism of acupuncture in treating simple obesity. METHODS: Central nerve push-pull perfusion and biochemical technique were used to observe the effect of acupuncture on obese rats, and the obese parameters and the change of monoamine transmitters and activity of ATPase in the lateral hypothalamic area (LHA) of the obese rats were investigated. RESULTS: The levels of noradrenaline (NA) in LHA of obese rats were higher than those in the normal group, but the level of serotonin (5-HT) and the activity of ATPase in LHA of obese rats were lower than those of the normal rats. After acupuncture treatment, the weight of the obese rats reduced, while the level of NA in LHA reduced and the 5-HT and activity of ATPase increased (P < 0.05, P < 0.01). CONCLUSION: The effective regulation on LHA of obese rats is possibly one of the key factors in the anti-obesity of acupuncture.

Acupuncture↗

PubMed2000

[Preliminary clinical observation on treatment of chronic rhinitis with rhinitis spray].

OBJECTIVE: To investigate the clinical effect of Rhinitis Spray (RS) in treating chronic rhinitis. METHODS: Eighty patients with chronic rhinitis were divided into three groups, and treated with RS, ephedrine and normal saline respectively. RESULTS: The short-term effective rate in the three groups was 89.3%, 66.7% and 8.0% respectively. RS was effective in alleviating symptoms, increasing IgG level in nasal discharge, improving ventilation of nasal cavity and transfer function of cilia of nasal mucosa obviously. CONCLUSION: The therapeutic effect of RS in treating chronic rhinitis is good.

Administration, Inhalation↗

PubMed2000

[Quantitative evaluation of dyspnea and the effects of M-receptor antagonist on dyspnea in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the method of quantitative evaluation of dyspnea and to investigate the effects of M-receptor antagonist inhalation on dyspnea in patients with chronic obstructive pulmonary disease (COPD) during exercise. METHODS: Cycle exercise test was used in 27 patients with COPD and the effects of ipratropium bromide, a M-receptor antagonist, by inhalation on dyspnea and exercise capacity in the patients were observed. RESULTS: (1) Dyspnea index as Borg scale was closely correlated with oxygen uptake (V(O2)) during exercise in all the patients. Three variables for quantitative evaluation of dyspnea could be derived from the linear regression line. They were Borg scale slope (BSS), threshold load of dyspnea (TLD), and breakpoint load of dyspnea(BLD). (2) BSS was negatively correlated with forced expiratory volume in one second to forced vital capacity ratio (r = -0.519, P < 0.01) and diffusing capacity of the lungs for carbon monoxide (r = -0.497, P < 0.01) but positively correlated with residual volume/total lung capacity (r = 0.396, P < 0.05). (3) Inhalation of ipratropium bromide could significantly improve BSS [from (12.09 +/- 3.41) BS x L(-1) x min(-1) to (8.57 +/- 2.79) BS x L(-1) x min(-1), P < 0.01] and BLD [from (0.77 +/- 0.19) L/min to (0.81 +/- 0.14) L/min, P < 0.05] during exercise. CONCLUSIONS: (1) BSS, TLD and BLD could be used as reliable and convenient variables in quantitative evaluation of dyspnea in patients with COPD. BSS and BLD could to some extent reflect the severity of the disease. (2) M-receptor antagonists could alleviate dyspnea and increase exercise capacity in patients with COPD.

Adult↗

PubMed2000

[Association between genetic polymorphism of dopamine transporter gene and susceptibility to Parkinson's disease].

OBJECTIVE: To explore the association between genetic polymorphism of dopamine transporter (DAT) gene and susceptibility to Parkinson's disease (PD). METHODS: The polymorphism of DAT 3' VNTR was analyzed in 171 PD patients and 180 unrelated healthy controls with amplification fragment length polymorphism (Amp-FLP). RESULTS: Five alleles of the DAT 3' VNTR were detected, consisting of 7, 8, 9, 10 and 11 copies of the 40 bp repeated sequence. The 10-copy allele was the most common one in both patients and controls. There were significant differences in both allelic and genotypic distributions of the DAT 3' VNTR between the patient and control groups (P = 0.016, P = 0.03, respectively; Fisher's exact test). The frequency of the 11-copy allele was significantly higher in patients (4.4%) than in controls (1.1%), with an odds ratio of 4.08 (95% confidence interval 1.25 approximately 14.7, P = 0.008). CONCLUSION: DAT 3' VNTR 11-copy allele is a genetic factor susceptible to PD in the population tested.

Adult↗

PubMed2000

[Association between cytochrome P-450 enzyme gene polymorphisms and Parkinson's disease].

OBJECTIVE: To explore the association between cytochrome P-450 enzyme gene polymorphisms and Parkinson's disease (PD). METHODS: The polymorphisms of CYP1A1 and CYP2E1 gene were analyzed in 158 PD patients and 150 unrelated healthy controls with PCR-RFLP and ASA techniques. RESULTS: (1) Of the 46 patients with early-onset PD, the frequency of the m2 allele was significantly higher than that in their matched controls, with an odds ratio of 2.459 (P < 0.005); the frequencies of the m1m2 and m2m2 genotypes were significantly higher than those in their matched controls with odds ratios of 2.99 (P < 0.01) and 6.22 (P < 0.025), respectively. In contrast, no differences were observed when the frequencies of individuals with the CYP1A1 MspI alleles or genotypes among patients with late-onset PD and their matched controls were compared (all P > 0.05). (2) Of the 46 patients with early-onset PD, the frequency of the G allele was significantly higher than that in their matched controls, with an odds ratio of 2.432 (P < 0.005); odds ratio was 6.167 in homozygotes for G allele (P < 0.01). Similarly, the frequency of the G allele was also significantly higher in late-onset PD patients than in their matched controls, with only an odds ratio of 1.649 (P < 0.01). In contrast, no differences were observed when the frequencies of individuals with the CYP1A1 exon 7 A4889G polymorphic locus genotypes among patients with late-onset PD and their matched controls were compared (P > 0.05). (3) No differences were observed when the frequencies of individuals with the CYP2E1 RsaI and PstI alleles or genotypes among patients with early- and late-onset PD and their matched controls were compared (all P > 0.05). CONCLUSIONS: Our data suggest that CYP1A1 gene polymorphisms might be a genetic susceptible factor for early-onset PD, and CYP2E1 RsaI and PstI polymorphisms might not be a genetic susceptible factor for both early- and late-onset PD in the Chinese population tested.

Adult↗

PubMed2000

[A correlative study on the thyroid stimulating hormone levels between pregnant women and their newborns].

OBJECTIVE: The correlation between serum thyroid stimulating hormone (TSH) levels in pregnant women and their neonatal cord blood was explored. METHODS: With immunoradiometric assay (IRMA) technique, the serum TSH levels of 500 pregnant women and the cord blood TSH levels in the iodine deficiency areas (study group) were tested, while the TSH levels of 100 normal pregnant women and their newborns in iodine sufficient areas (control group) were compared. RESULTS: (1) In pregnant women, the mean serum TSH level in study group was significantly higher than that of control [(5.25 +/- 2.43) mU/L VS (4.69 +/- 1.34) mU/L, P < 0.01]. In newborns, the mean cord blood TSH level in study group was significantly higher than that of control (6.83 +/- 4.71) mU/L VS (5.32 +/- 3.02) mU/L, P < 0.001]. (2) The serum TSH levels in pregnant women were positively correlated with the cord blood TSH levels of their newborns in both groups. (3) The serum TSH levels of pregnant women was negatively correlated with their free triiodothy-ronine levels. CONCLUSION: The iodine nutrition status of newborns could be evaluated by monitoring the TSH levels of pregnant women.

Female↗

PubMed2000

[Effect caused by uptake of different levels of calcium to enamel fluorosis in rats].

OBJECTIVE: To study the effects caused by uptake of different levels of calcium to dental fluorosis in rats. METHODS: Weanling rats were raised on water containing 0.1 mol/L fluoride and food containing low, normal and high levels of calcium for 2 months. The concentration of fluoride in enamel was analysed by F-ion-selective electrode. The microradiographic examination and light-density analysis were performed. The enamel structure was examined under SEM. RESULTS: The more calcium was ingested, the lower level of fluoride amount in enamel was observed (P < 0.01). With increasing food calcium ingestion, the light density value was decreasing, and the level of enamel mineralization was increasing (P < 0.01). CONCLUSIONS: With increasing food calcium ingestion during the development of teeth, the level of dental fluorosis is decreasing. The calcium supply is effective in protection from fluoride toxicity to a certain extent.

Animals↗

PubMed2000

[Treatment of humeral shaft nonunion with interlocking nail and percutaneous injection of bone marrow].

OBJECTIVE: To investigate the effect of treatment of humeral shaft nonunion with interlocking nail and percutaneous injection of bone marrow after operation. METHODS: Twenty-five adult patients with humeral shaft nonunion, initially treated with plates, intramedullary nails, or external fixators changed to use RussellTaylor reamed antegrade intramedullary nails with autologous bone grafting and percutaneously bone marrow injection into the fracture sites ten days after the operation to promote union. RESULTS: All patients achieved a solid union with good function. The union period was a median of 4.5 months. CONCLUSION: We believe that the procedure may provide firm internal fixation and improve activity of osteoblasts in fracture sites for accelerating fracture healing.

Adolescent↗

PubMed2000

[A clinical study on fresh amniotic membrane transplantation for treatment of severe ocular surface disorders at acute inflammatory and cicatricial stage].

OBJECTIVE: To investigate the safety and evaluate the effect of fresh amniotic membrane transplantation to reconstruct the ocular surface with severe inflammation and scarring. METHOD: Amniotic membrane transplantation (38 cases, 46 eyes), or combined with either limbal transplantation (9 cases, 9 eyes) or lamellar keratoplasty (8 cases, 8 eyes) was performed on ocular surface burns (5 cases, 6 eyes), recurrent Mooren's ulcer (8 cases, 8 eyes) and severe symblepharon (38 cases, 46 eyes). All the patients were followed-up for 6 - 18 months (mean, 11 months). Impression cytology was examined in 21 eyes with normal tear secretion post-operatively. RESULTS: No acute rejection was observed after fresh amniotic membrane transplantation. No progressive melt and perforation were seen in five out of six eyes with burns in reconstructed ocular surfaces. Neovascularization, pseudopterygium and iris atrophy were not found during the follow-up. Visual acuity was improved in various degrees. Corneal ulceration was not noted in 8 cases (8 eyes) with frequently recurrent Mooren's ulcer. Ocular surface reconstruction was successful in 46 of 49 eyes with severe symblepharon. Symblepharon occurred in the remaining three eyes but much less than pre-transplantation in degree. Amniotic epithelia have been examined in about three months on the transplanted eyes with normal tear secretion. CONCLUSION: Fresh amniotic membrane can be used as a graft to reconstruct ocular surface. Such transplantation can effectively reduce neovascularization, fibrosis and inflammation. Our data indicated that complete removal of pathological tissues and perfect fixation of amniotic membrane graft are crucial steps in the reconstruction of ocular surface.

Acute Disease↗

PubMed2000

[The effect of artificial tears on corneal surface regularity in dry eye].

OBJECTIVE: To evaluate the regularity of corneal surface and the effect of artificial tears on the corneal surface regularity in dry eye. METHODS: The surface regularity index (SRI), surface asymmetry index (SAI), the indices of TMS-1 corneal topography system, and potential visual acuity (PVA) were used to investigate the corneal regularity and corneal vision in 33 normal subjects (64 eyes) and 22 dry eye patients (42 eyes) before and after instillation of artificial tears. RESULTS: The SRI and SAI were significantly elevated and the PVA was remarkably decreased in patients with dry eye compared to that of normal subjects (P < 0.001). The average amount of astigmatism was also significantly increased in dry eye compared to that in normal eyes (P = 0.02). In the patients with dry eye, the SRI and SAI were positively correlated with corneal fluorescein staining scores. The SRI, SAI and astigmatism were significantly reduced, the PVA was improved and the irregular topographic pattern was markedly decreased in the dry eyes after the usage of artificial tears. CONCLUSION: The dry eye has an irregular corneal surface and the indices of TMS-1, SRI and SAI can be used to objectively diagnose this disorder, evaluate the severity of the dry eye and the effect of artificial tears on it. Artificial tears can smooth the corneal surface and improve the visual acuity in patients with dry eye.

Aged↗