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Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 613 records · Page 34Linked to original sources
PubMed1997

Acanthamoebae bind to rabbit corneal epithelium in vitro.

PURPOSE: Selection of an appropriate animal model is crucial for the investigation of the pathogenesis of Acanthamoeba keratitis. To this end, it has been reported that fluorescein isothiocyanate (FITC)-labeled Acanthamoeba castellanii bind to human, pig, and hamster corneas, but not to rabbit corneas in organ culture. However, 35S-labeled A. polyphaga and A. culbertsoni have been found to bind to rabbit corneal epithelium grown in tissue culture. The purpose of the current study was to establish whether A. castellanii bind to rabbit corneal epithelium in organ culture. METHODS: Two different adhesion assays were used to determine whether 35S-labeled and FITC-labeled A. castellanii bind to epithelium of corneal buttons in vitro and, if so, whether the binding is temperature-dependent, enhanced by injury, and inhibited by specific saccharides. Ameba binding to rabbit corneal epithelium was also evaluated by scanning electron microscopy. The binding of A. castellanii to corneal epithelium of three different species (human, pig, and rabbit) was compared. RESULTS: Both 35S-labeled as well as FITC-labeled parasites were found to bind to epithelium of rabbit corneal buttons in vitro. Although the parasites bound avidly to the corneas at 25 degrees C and 35 degrees C, little binding was observed at 4 degrees C. Injury enhanced the binding. Methyl alpha-D-mannopyranoside, but not other saccharides (alpha-L-fucose and beta-galactose), inhibited binding of the parasites to the epithelium of rabbit corneas. By scanning EM, A. castellanii were found to adhere, invade, and penetrate the epithelium of rabbit corneas. Compared with rabbit corneas, ameba binding to pig, and human corneas was only 1.2 and 1.4 times higher, respectively. CONCLUSIONS: Rabbit animal model may prove useful for investigation of the molecular mechanisms that mediate adhesion of Acanthamoeba to corneal epithelium.

Acanthamoeba↗
PubMed1997

[Distribution and contrast enhanced CT appearance of abdominal tuberculous lymphadenopathy].

PURPOSE: To clarify the contrast enhanced CT features and anatomic distribution of the disseminated vs non-disseminated tuberculosis (TB) involving abdominal lymph nodes. MATERIALS AND METHODS: The contrast enhanced CT findings of abdominal lymphadenopathy in 25 patients, including disseminated TB associated with miliary TB of the lung (n = 5) and non-disseminated TB (n = 20), were retrospectively evaluated in a blind review to assess our criteria of morphology, density and location of the involved lymphadenopathy. RESULTS: The enhancement patterns of disseminated TB were not different from those of non-disseminated TB. Ninety-six percent of the patients had peripheral rim enhancement, and 60% showed a multilocular appearance. The enlarged lymph nodes of TB were less than 4 cm in diameter. Lymphadenopathy caused by hematogenous dissemination often accompanied splenic involvement showing multiple low-density foci in the spleen. The predominant sites of lymphadenopathy of disseminated TB were hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric, and both upper and lower portions of the retroperitoneal lymph nodes, whereas non-disseminated TB mainly involved hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric and upper retroperitoneal lymph nodes, excluding the lower retroperitoneal lymph nodes. By combining contrast enhancement patterns and the anatomic distribution of lymphadenopathy shown on the contrast enhanced CT images, reviewers made a correct diagnoses of tuberculosis in 94%, of cases, with a specificity of 95% and sensitivity of 92%. CONCLUSION: Contrast enhanced CT patterns correlate well with the pathologic features of tuberculous lymphadenopathy. A different anatomic distribution between disseminated and non-disseminated TB involving the lower retropentoneal lymph nodes was recognized in this study.

Abdomen↗
PubMed1997

[Analysis of genome-type, serovar and antibiotic susceptibility of Pseudomonas aeruginosa isolated in Beijing Hospital China in 1991 to 1993].

We analyzed the in vitro antibiotic susceptibility pattern and serovar for 192 strains of Pseudomonas aeruginosa isolated at Beijing Hospital(China) from October 1991 to October 1993. The frequency of resistant strains was high, more than 15%, for ceftazidime, cefsulodin, cefoperazone, aztreonam, gentamicin, tobramycin, tosufloxacin, ofloxacin and fosfomycin. The incidence of resistants against piperacillin and imipenem was significantly low. Among the 192 strains, 16 were designated as being multi-drug resistant strains(i.e.; resistant to more than 8 drugs out of 11 drugs), and all of the multi-drug resistant strains were isolated from inpatients. Predominant serovar of 192 strains were 60(31.3%) for G, 28(14.7%) for E, and 24(12.5%) for I. Multi-drug resistant strains have no characteristic serovar. Restriction enzyme SpeI digestion analysis(using pulse field electrophoresis) of P. aeruginosa-genome yielded several common patterns, and was shown to be useful for tracing the route of nosocomial infection. Further, isolates with closely related genome type, in which the size of one digested band was different, showed a different minimum inhibitory concentration of fosfomycin in one genome type or new quinolones in the other genome type. Analysis of genome type and antibiotic susceptibility pattern may exhibit the antibiotic resistant gene.

Anti-Bacterial Agents↗
PubMed1997

[An experimental study of the endothelin-1 change in rat kidney after severe burn].

OBJECTIVE: To observe the changes of endothelin-1 (ET-1) concentration, immunohistochemical distribution, mRNA expression and localization in kidney of severe burn rat. METHODS: Wistar rats sustained with 30% TBSA III degree burn were divided randomly into 6 groups: normal control, 1, 3, 6, 12, and 24 postburn hour (PBH). The items studied were: the level of ET-1 in renal vein plasma and kidney tissue (cortex, outer medulla and inter medulla respectively), immunocytochemical distribution of ET-1 in kidney tissue by light and electron microscopy, mRNA expression of ET-1 in kidney by northern blot hybridization, localization and enumeration of mRNA expressiong cells of ET-1 by in situ hybridization. RESULTS: The rat kidney secretion and mRNA expression of ET-1 more evidently increased at 1, 3 PBH respectively than in normal control (P < 0.01), They distributed primarily on endothelial cells, glomerular mesangial cells. Tubular epithelial cells reached maximal mRNA expression and immunoreactivity at 3, 6 PBH respectively. Immune electron microscopic study demonstrated that ET-1 (gold particles) localized on the intracellular lumen surface of endothelium but on both apical and basal surfaces of epithelium. CONCLUSION: Secretion and mRNA expression of ET-1 increased obviously in kidney in early stage after severe burn.

Animals↗
PubMed1997

[Role of endogenous endothelins in renal injury in burnt rats].

Endothelins are potent vasoconstrictors released by endothelium, and their concentrations, which may be involved in the pathophysiology of burn injury, are increased in burn patients. The purpose of this study was to investigate the role of endogenous endothleins in postburn renal injury. 30% TBSA III degree burnt rat model was used, and 72 male Wistar rats were studied: 32 burnt rats received intravenous infusion of the non-selective ETA-ETB receptor antagonist PD145065 (1 mumol/Kg body weight) for 3 hours (group 1); other 32 burnt rats received only the vehicle (0.5 ml/250 g/h) (group 2). The rats both in group 1 and group 2 were given adequate resuscitation via different ways. 8 healthy rats were normal controls. In group 2, the blood flow of kidney decreased sharply, while marked lipoperoxidation damage and ATP depletion in kidney occurred although the arterial blood pressure remained unchanged postburn after sufficient fluid was given. Administration of endothelin receptor antagonist PD145065 has been demonstrated to be able to prevent kidney from damage to some extents both morphologically and biochemically by means of increment of blood flow, stimulation of the activity of SOD, enhancement of the contents of ATP and ADP, and reduction of the severity of edema in kidney. These results suggest that endogenous endothelins contribute to renal injury in the early postburn stage in rats through vascular constriction and tissue hypoxia which in turn induced ATP depletion and lipoperoxidation damage.

Adenosine Triphosphate↗
PubMed1997

[Effects of CD11/CD18 antibody on adhesive force between polymorphonuclear neutrophil and endothelial cell in response to burn serum in vitro].

UNLABELLED: Our previous studies have proved that a great number of polymorphonuclear neutrophils (PMN) adhered to endothelial lining and induced endothelial cell (EC) injury. This study was attempted to investigate the change in adhesive force between PMN and EC in response to burn patients' serum within 24 hours and effects of antibody against CD11/CD18 on PMN-EC adhesive force. Burn serum was isolated from 4 burn patients (III degrees 20%-50% TBSA) within 48 hours after burn injury. PMNs were isolated from 8 volunteers. Adhesive force between a PMN and a HUVEC was calculated by means of micropipette technique at 1 h, 3 h, 6 h, 12 h, 24 h after PMN or HUVEC incubated with burn serum or normal serum. Five individual PMN-HUVEC pairs were measured for each sample. All data were analyzed statistically using the t test. RESULTS: 1. The adhesive force between a single PMN-HUVEC pair increased sharply after PMN incubated with burn serum, which reached the maximun level at 1 h after incubation and remained at this level in the following 23 hours. However, the adhesive force was reduced by 78.5%, 72.5%, 75.2% at 1 h, 6 h, 24 h, respectively after the PMNs were pretreated with CD11/CD18 mAb; 2. The adhesive force between a single burn serum stimulated-HUVEC and PMN pair increased gradually, reached peak at 12 h and remained at this level in the following 12 hours. CONCLUSIONS: Burn serum could induce PMN-EC adhesion, with related to PMN aggregation in internal organs and EC damage after burn injury. Antibodies against CD11/CD18 could partially block PMN-EC adhesion and might reduce EC injury induced by activated PMNs.

Adolescent↗
PubMed1997

[The measurement of cardiac myosin light chain I in diagnosis of postburn cardiac injury].

In order to estimate myocardial damage after severe burn injury, the cardiac myosin light chain I (CMLC1) contents and myocardial enzyme spectrum (CK, AST and LDH) in serum were measured in rats with full thickness burn of 30% TBSA. The results showed that the CMLC1 contents in serum increased markedly at 1 h postburn and about 20 times higher than control value at 12 h postburn, remaining at high level at 24 h or 48 h postburn, and decreasing slightly at 72 h postburn. CK, AST and LDH activities were increased at 3 h postburn and tended to decrease markedly at 24 h or 48 h postburn, recovering to control level at 72 h postburn. These results suggest that high increase in CMLC1 in serum implies that myocardium is damaged after severe burn injury, and it can be used as a reliable index in the diagnosis of postburn cardiac injury with higher sensitivity and specificity than myocardial enzyme spectrum.

Animals↗
PubMed1997

[Multifactor analysis on proliferative retinopathy in elderly patients with type II diabetes].

UNLABELLED: To evaluate the importance of different risk factors and their mutual interactions in the occurrence of proliferative diabetic retinopathy (PDR) in the elderly patients with type II diabetes, an investigation was carried out on the relationship between PDR and various risk factors in 98 elderly cases of type II diabetes by way of stepwise regression analysis method. Results showed: (1) the average course of PDR was longer than that of diabetic patients without diabetic retinopathy (P < 0.01). Patients with PDR had higher values of BUN (P < 0.01), Cr(P < 0.05), GHbA1c(P < 0.01) and TC(P < 0.01) than those without retinopathy. Patients with PDR had higher coincidences of hypertension, coronary artery disease, proteinuria and urine microalbumin than those without retionpathy (P < 0.01) respectively, (2) multifactor analysis showed that BUN was one of the most important variables positively correlated with PDR, second to it in orders were the course of diabetes militus, GHbA1c, hypertention, proteinuria and urine microalbumin and TC. CONCLUSION: To prevent the occurrence and progress of PDR in the elderly patients with type II diabetes, it is important not only to control blood sugar, but to control blood pressure and relieve renal damage.

Aged↗
PubMed1997

[The effect of phenytoin in healing of fracture of rabbits].

It was reported that the systemic use of phenytoin could promote healing of fracture. In order to observe the effect of local application of phenytoin in the healing of fracture, the experiment was performed. Seventy-two rabbits were divided into three groups. Fractures were created on both radius of all rabbits. Group 1, intraperitoneal injection of phenytoin with a dosage of 50 mg/kg per day; Group 2, local use of phenytoin with a dosage of 40 mg/kg was injected in the fracture site every seventy-two hours, and Group 3, injection mormal saline of in the control group. Eight rabbits in each group were sacrificed in the 9th, 16th and 30th days after operation respectively. By X-ray excuiualtion, the healing of fracture was observed. Dry and wet weights of the callus were determined. After HE and Mallory's stain, the samples were examined under microscope. Results showed that both local and systemic use of phenytoin promoted healing of fracture. The effects of phenytoin in the two groups were the same and had no significant difference.

Animals↗
PubMed1997

[The effect of wumingyi chongji on BMP content in callus].

A kind of Chinese herb medicine--Wumingyi chongji could promote fracture healing had been proved. In order to disclose the mechanism, a standard fracture model was produced in 50 healthy male Newzealand rabbits. The animals were randomly divided into experimental group and control group. Another 5 rabbits without operation act as nomal. By immunohistochemical study, the bone morphogenetic protein (BMP) content in callus was calculated by computerized interacive morphometry (CIM) in the 1st, 2nd, 3rd, 4th, 5th week after fracture. The results were: BMP in callus was much more than in nomal (P < 0.01); BMP in callus increased from the 1st week to the 3rd week, decreased from 4th week to 5th week, and was more in experimental group in the 1st and 2nd week than in the control group (P < 0.01). The highest BMP content appeared in the 2nd week in the experimental group, while in the 3rd week in the control group. It was concluded that Wumingyi chongji could promote osteoblast to synthetize BMP, BMP induce preosteoblast change into osteoblast. Thus the rate of fracture healing could be increased.

Animals↗
PubMed1997

[Experimental study in vivo on implantation of autogenous tendon cells after combining culture with carbon fibers].

In order to investigate the possibility of repairing injuried tendon with living artificial tendon, after combining culture, subcultured autogenous tendon cells with carbon fibers were implanted into the calcaneous tendon of rabbits. In different stages, the synthesis of type I collagen and their relevant morphological changes were observed. The results showed as follows: after implantation, tendon cells continued proliferating. Four weeks after implantation, tendon cells were detached from the carbon fibers and proliferated and produced collagen among the carbon fibers. The collagen fibrils were linked with each other to formed a dense structure. In the linkage site, the collagen fibrils originated from the implants joined to that from the ruptured end of the tendon, which meaned that the implant was healed with the recipient tendon. Observed under scanning electronic microscope, the tendon cells were lined among the carbon fibers evenly and in order, the collagen fibrils joined each other and formed an network, the fibrils were lined parallel to the carbon fibers. Under transparent electron microscope, the nucleolus were clear and organelle were abundant.

Animals↗
PubMed1997

[The effect of insulin-like growth factor-1 on cyclic change of tendon cell].

In order to investigate the effect of insulin-like growth factor-1 (IGF-1 on the cyclic change of tendon cell, the 6th generation of cultured tendon cell were selected, and 20 ng/ml IGF-1 was added to the medium. After 48 hours, the cells were determined by flow cytometer, as well as the control cells. The results showed that the time of G1 phase, DNA synthesis phase and G2M phase in IGF-1 group were 11.8 hours, 21.4 hours and 6.8 hours respectively, while those were 25.6 hours 22.6 hours and 21.8 hours respectively in the control group. It was showed that the time needed for G1 phase and G2M phase was shortened by IGF-1.

Cell Cycle↗
PubMed1997

[Implantation of allogenic osteoblast combined with calcium phosphate composites].

The aim of this experiment was to study the osteogenesis in vivo of allogenic osteoblast combined culture with calcium phosphate composites. The osteoblasts were obtained by enzymatic digestion of periosteum from fibula subcultured to 13 generations, the cells were combined culture with hydroxyapatite and biphasic calcium phosphate. Subseguently, the composite was implanted into rabbits subcutaneously or intramuscularly. The blank material was implanted in the contralateral side as control. Four weeks later, all animals were sacrificed. All the implants were examined by gross observation, histological examination and EDXA. The results showed: 1. obvious ingrowth of connective tissue with very little inflammatory reaction; 2. new bone formation in the composites with deposit of Ca and P on the surface of osteoblast, but none in the blank materials; 3. no significant difference of new bone formation between the different sites of implantation or different materials, but those implanted intramuscularly had lamellae form of new bone while those implanted subcutaneously had only mineralization of extracellular matrix. The conclusion were: 1. the composites are biocompatible with prior osteogenesis property; 2. periosteal-derived allogenic osteoblasts obatined by enzymatic digestion could survive following implantation with bioactivity; 3. rich blood supply might be advantageous to new bone formation and its maturation.

Animals↗
PubMed1997

[Experimental study on biological characteristics of tenocyte and fibroblast in rabbit].

In order to study the biological characteristics of tenocyte and fibroblast, the former was obtained from rabbit's tendon, and the latter from rabbits's skin. Both cells were cultured according Heuderson's method. The cell morphology, strapping and expanding time, and the type of collagen fiber synthesized in culture were observed. The results showed that the strapping and expanding time of fibroblast was faster than that of tenocyte. The cellular arrangement of fibroblast was irregular, but that in tenocyte was regular. Type I and III collagen of fibers were found in cultured fibroblost while only type I collagen fibers were found in culture of tenocyte. The tenocyte and fibroblast could be identified individually by strapping and expanding time, arrangement of cells and type of collagen fiber synthesized.

Animals↗
PubMed1997

[Morphological observation of combined-culture of tendon cell or fibroblast of rabbit with artificial materials in vitro].

In order to investigate the compatibility and growth between the tendon cell or fibroblast of rabbit and artificial materials, the combined-culture of the two cells with the carbon fiber, terylene and chitin was observed respectively. Results showed as following: in vitro, the compatibility of carbon fiber with these two cells was well, cell-adhesion ability was good as well. Few cells grew on terylene. Chitin inhibited the growth of either cells. No matter the tendon cell or the fibroblast, the amount of cells adhering on the carbon fiber was far more than that on terylene or chitin. When the three materials were interlaced together, the collagen fibers produced by the cells were arranged in direction parallel to the carbon fibers. As the time elapsed, the cells on the carbon fiber distributed evenly and enveloped the material in network-like fashion, this suggested that carbon fiber was a good material for producing living artificial tendon and ligament.

Animals↗
PubMed1997

[The expression of IGF-1 and its receptor in cultured tendon cell].

In order to study the expression change of insulin-like growth factor-1 (IGF-1) and its receptor genes in different generations of tendon cell in culture, Dig-labeled synthesized oligonucleotide probes were used to detect the mRNA expression in primary, 6th and 13th generation of tendon cell. The results showed that IGF-1 receptor mRNA was expressed in all of the 3 above generation tendon cells. IGF-1 mRNA was expressed only in primary and 6th generation cells. Tendon cell of 13th generation did not express IGF-1 mRNA. It might suggest that the absence of IGF-1 mRNA expression be one of the causes which led to the decrease of reproductive ability of 13th generation tendon cell.

Cells, Cultured↗