Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 505 records · Page 28Linked to original sources

PubMed1998

[Classification of measles control situation in different areas of China].

Based on initial description of measles epidemiology, principal component analysis and cluster analysis were applied to analyze the epidemiological pattern of measles in China. Several indicators of socioeconomic status, epidemiological characteristics of measles, as well as status of EPI performance were selected as creteria for classification. It was demonstrated that four groups could be identified as undercontrol, moderate, less advanced and poor areas in terms of the status of measles controlled program. Different strategies were recommanded for different groups. For the undercontrol areas, establishment of measles surveillance system should be prioritized. For the moderate epidemic areas, supplemental immunization should be considered while measles surveillance system is initiated. In the less advanced areas, supplemental immunization and strengthening outbreak response activities should be considered. For poor areas, routine measles immunization needs further improvement to reduce outbreaks.

Adolescent↗

PubMed1998

[Protective effect of tea on immune function in mice].

OBJECTIVE: To study the mechanism of preventive effect of tea on cancer by immune regulation. METHODS: A tumor model was induced in mice using carcinogen, 4-methyl-nitrosoamino-1-(3-pyridyl)-1-butanone (NNK), to examine their changes in immune function and the effects of green tea, mixed tea and polyphenol on protection from tumor. RESULTS: During the four weeks of observation after injection of NNK into mice, their immunological indicators, such as cytophagocytosis of macrophage in the abdominal cavity, chemiluminescence of peripheral leukocyte, delayed allergic reaction, count of antibody-forming spleen cells and activity of spleen nature killer cells, etc. increased or decreased to various extent, as compared with those in normal controls. It was found that whether green tea, mixed tea or polyphenol all showed significant protection from adverse changes in immune functions. CONCLUSION: Tea and its components had significant protection from early adverse changes in immune function in tumorgenesis induced by NNK.

Adjuvants, Immunologic↗

PubMed1998

Development of serial bio-shock tubes and their application.

OBJECTIVE: To design and produce serial shock tubes and further examine their application to experimental studies on blast injury. METHODS: Bio-medical engineering technique was used for the design and development of the serial shock tubes. One thousand four hundred and fifty nine animals (757 rats, 105 guinea pigs, 335 rabbits, 240 dogs and 22 sheep) were then used to test the wounding effects of the shock tubes. RESULTS: Three types of bio-shock tubes, that is, large-, medium- and small-scale shock tubes were made in our laboratory. The large-scale shock tube is 39 meters long; the inner diameter of the test section is 1 meter; and the maximum overpressure in the driving section is 10.3 MPa. A negative pressure could be formed by means of the reflected rarefactive wave produced by the end plate. The medium-scale shock tube is 34.5 meters long; the maximum overpressure in the driving section is 22 MPa; the test section is designed to be a knockdown, showing 5 basic types with inner diameter of 77 to 600 millimeters, which could be used for researches on overpressure, explosive decompression, underwater explosion, and so on. The small-scale shock tube is 0.5 meter long with the maximum endured overpressure of 68.6 MPa. Results from animal experiments showed that this set of shock tubes could induce various degrees of systemic or local blast injury in large or small animals. CONCLUSIONS: This set of bio-shock tubes can approximately simulate typical explosive wave produced by nuclear or charge explosion, and inflict various degrees of blast injury characterized by stability and reproducibility. Therefore, they can meet the needs of blast research on large and small animals.

Animals↗

PubMed1998

[The effect of blocking insulin-like growth factor-1 (IGF-1)-receptor system on tendon cell proliferation].

The purpose of this study was to find some solutions to the problem of tendon cell proliferation control. Under the condition of in vitro culture, several materials including IGF-1 receptor antibody and mRNA antisense oligonucleotide were added to the culture medium to block the IGF-1-Receptor system. The effect of the material on the tendon cell proliferation was judged by cell count after incubation of 48 hours. The results showed that both IGF-1 Receptor antibody (IGF-1R alpha) and IGF-1 Receptor mRNA antisense oligonucleotide had negative effect on tendon cell proliferation (P < 0.01 and P < 0.05). These findings lead us to think that the above two materials could be used in the experiment of tendon adhesion preventing and living ready-made tendon producing.

Cell Count↗

PubMed1998

[Xenogeneic antigens and immune response in pig to man xenograft].

Limitation of donor source for allograft makes the research on xenograft progress. Pig is regarded as one of the ideal donor animals. The major obstacle in xenograft is hyperacute rejection, which is caused by complements after they are activated by xenogeneic antigens combined with natural antibodies. It has been confirmed that alpha-Gal is the major target antigen, whose expression is incharged by alpha-1,3 galactosyltransferase (alpha-GT). The approaches to overcome hyperacute rejection against alpha-Gal included: immunoadsorption of xenogeneic natural antibodies, lysis of antigen by enzyme and genetic manupilation to obtain animal lack of alpha-GT. Besides alpha-Gal, there were other antigens binding to human serum antibody, such as gp65 and gp100, which was expressed on PAEC after induced by TNF, the A-like antigen. But their function was still unknown. It was debatable on the role of MHC in xenograft. Both direct and indirect pathway were involved in cellular response in xenograft.

Animals↗

PubMed1998

[Analysis of the density of insulin-like growth factor-1 receptor on tendon cell].

For the purpose of understanding the distribution of insulin-like growth factor-1 (IGF-1) receptor on the tendon cell, the continuous cultured tendon cell line was studied by following experiments. With the methods of immunohistochemical study and flow cytometric study, the density of IGF-1 receptor of the primary, 6th and 13th generation of tendon cell was analyzed. The results showed that there was no difference of the receptor density among those generations. However, in the cell cycle, the numbers of IGF-1 receptor in G2M phase tendon cells were more than that in G1 phase cells (P < 0.01). These works provided sufficient evident which suggested there were stable density of IGF-1 receptor on the tendon cell though out the life span of tendon cell. This may build some foundation in growth control of tendon cell by growth factor in the research of tendon tissue engineering.

Cells, Cultured↗

PubMed1998

[The recent advances in the study of tissue engineering tendon].

This paper reviewed the main achievements in the research on tissue engineering tendon, focusing on major problems concerning the substitute for extracellular matrix (ECM) of tendon, biological characteristics of tendon cells, and tendon cells compounding with ECM substitute. It was concluded the important problems in the study of the tissue engineering having specific reparative functions could be: to prepare the ECM materials suitable for the tendon cells to attach, grow, and function; to establish the tendon cell line whose growth, proliferation, and immunological antigenicity could be modulated and controlled, and simulating the mechanical environment of tendon in vivo, to adopt three-dimensional tendon cell culture method.

Animals↗

PubMed1998

[Restoration of supination of forearm by flexor carpi radialis transfer].

The dysfunction of supination of forearm following injury of brachial plexus or poliomyelitis always affects the function of hand. To find the dynamic muscle for restoration of the supination, the flexor carpi radialis was investigated on fifty male cadavers. The blood supply of the muscle was polygenic, mainly derived from the humoral and radial arteries. The movement of the muscle was innervated by median nerve. If the proximal 1/3 belly of the muscle was reserved, the blood supply and innervation of the complete muscle was reserved. According to the anatomic data, the operative procedure was designed as following: transfer the distal 2/3 of flexor carpi radialis over the ulnar aspect of the forearm to the dorsal-radial side, the tendon was fixed on the radius shaft 6 to 10 cm proximal to the styloid process with forearm in full supination. Four patients were treated and after followed up for 3.2 years average, the supination restored. It was discussed that in case of paralysis of the flexor carpi ulnaris and pronator teres, the optimal choice to restore the supination would be flexor carpi radialis.

Adult↗

PubMed1998

[Cellular sociological characteristics of osteoblasts].

There is a great hope to treat long bone defects with bioactive artificial bone constructed by osteoblasts and biomaterials, in which the key point is to provide an optimum environment for the normal function of osteoblasts. The cellular sociological characteristics of osteoblasts were summarized and it was suggested that the ideal bioactive artificial bone should be composed of inorganic and organic materials together with cellular components such as osteoblasts and vascular endothelial cells, and combined with control release of growth factors, following its implantation it could be vascularized very soon and merged with the host bone by bony consolidation.

Bone Substitutes↗

PubMed1998

[Experimental study on the efficacy of methyl prednisolone in the treatment of traction injury of spinal cord in rabbits].

In order to study the prophylactic and therapeutic effect of methyl-prednisolone (MP) on traction injury of spinal cord, 48 rabbits were divided into four groups randomly. According to decreasing amount of the amplitude of P1-wave, 50% reduction lasted for 5 min and 10 min with MP as experimental group, and 50% 5 min and 10 min with NS as control, the changes of amplitudes were monitored by, and the function of the spinal cord was assessed. The amounts of MDA and SOD of the spinal cord tissue were determined and the pathomorphological changes of the spinal cord were observed. The results showed that in the experimental groups, the recovery of P1-wave was quicker, the Tarlov and Molt value were decreased, the density of gray matter of the anterior horn and the myelinated nerve fiber of white matter of 100 microns diameter were higher, the SOD and MDA was decreased and the degenerative and necrotic degree of neuron and nerve fiber were milder. Where in the control groups all the above items were just on the opposite. The conclusions list as follows: the application of MP before operation of spinal deformity might prevent traction injury of the spinal cord during operative correction of spinal deformity, and could also minimized the secondary damage to spinal cord from traction injury if MP was used in time. The action to MP were summarized as improving the microcirculation, inhibiting the hyperoxidation of lipid and accelerating the recovery of SCEP.

Animals↗

PubMed1998

[One-stage operative treatment of atlanto-axial instability with stenosis of lower cervical level of spinal canal].

To cure patients suffering from atlanto-axial instability following old fracture of odontoid process concomitant with stenosis of lower end of cervical spinal canal, a new operative method was designed. It included atlanto-axial fusion by Gallie technique and resection of right half of the laminae of C3-C7 spine at one stage. A female of 63 years old was treated. She was admitted with neck pain and numbness of the upper and lower limbs. A history of neck injury was noted in enquiry. In physical examination showed the sensation of pain of the upper limbs was decreased and the muscle power of the upper and lower limbs ranged from III degree to IV degree. The X-ray film and MRI suggested that there was instability of the atlanto-axial joint with stenosis of 4th-6th cervical spinal canal. The operation was satisfactory. After operation, the patient was followed up for 11 months. The physical examination indicated that sensation of the upper limbs had recovered to normal and the muscle power of the upper limbs reached IV degree and that the lower limbs reached V degree and X-ray showed bony fusion of the atlanto-axial joint. The conclusions were: 1. The stability of atlanto-axial joint was reconstructed with expanding of the spinal canal at the same time. 2. The duration, risk and cost of the therapy were reduced, and maintenance of the stability of the cervical spine throughout whole period of treatment was recommended.

Atlanto-Axial Joint↗

PubMed1998

[Effects of abnormal distribution of calcium on impairment of myocardial mechanics in the early stage of thermal injury].

OBJECTIVE: To investigate the effect of abnormal Ca2+ distribution on impairment of myocardial mechanics in the early stage of thermal injury. METHODS: Calcium (Ca2+) changes were observed within subcellular distribution in situ in rat heart with calcium cytochemical probe and electron probe microanalysic technique. Meanwhile, myocardial mechanics and energy metabolic changes were investigated after thermal injury. RESULTS: The results demonstrated that levels of cytoplasmic Ca2+ in cardiomyocytes increased at 1 hour, followed by enhanced mitochondrial Ca2+ at 3 hour after burn injury. Parallel to the changes in Ca2+, there were decrease of myocardial contraction, relaxation capacity and increase of ventricular wall stiffness in burned rats. A lower level of heart energy changes was observed from 6 to 12 hours, compared with control group. CONCLUSION: The results indicate that subcellular Ca2+ abnormal distribution in myocardium caused by burn injury may be associated with rigor contraction and decreased relaxation of myocardium.

Animals↗

PubMed1998

[Expression of mRNA for endothelin-1 and its receptors in rat kidney after burn injury].

OBJECTIVE AND METHODS: We studied expression of messenger RNAS for endothelin-1 (ET-1) and its receptor subunits (ETA, ETB) by northern blot hybridization and in situ hybridization in rat kidney following 30% TBSA full thickness burns. RESULTS: Expressions of that ET-1, ETA, and ETB mRNA expression are all evidently increased at 1 hour postburn. ET-1 and ETA reached its maximal mRNA expression at 3 hour postburn. ET-1 mRNA distributed primarily on glomerular endothelial cells and tubular epithelial cells in cortex. ETA mRNA predominantly presented on smooth muscle cells of small arterioles in renal cortex. However, the peak time of ETB mRNA expression is at 6 hour postburn and mainly localized on renal medullary tubular epithelial and collecting duct cells. CONCLUSION: These findings suggest that 1. ET-1 acts principally as a local paracrine/autocrine peptide. 2. Increased ET-1 that activated ETA receptors accentuated expression on vascular smooth muscle cells will result in renal cortex ischemia. 3. Accentuated expression of ETB receptor on tubular epithelial cells may induce renal natriuretic action and reduction of water execretion. 4. Increased ET-1 and its receptors in kidney play an important role in the pathogenesis and development of renal function impairment following severe burn.

Animals↗

PubMed1998

[The dynamic changes and significances of endothelins in early burned rats].

OBJECTIVE: To elucidate the significance of endothelins in visceral injury at the early stage of burn. METHODS: By use of a 30% (III degree) total body surface area (TBSA) burn rat model, we measured the concentration of endothelins in plasma, heart, liver, lung, kidney, and observed the effects of PD145065, a kind of non-selective ETA-ETB receptor antagonist, on visceral impairment. RESULTS: Not only did the endothelin concentration in plasma of burnt rat elevated significantly, showing a peak at 6 hours postburn, but also the endothelin contents in internal organs apparently increased. The changes in endothelin in liver or kidney were negatively correlated with the alteration in renal or hepatic blood flow. Moreover, administration of endothelin receptor antagonist PD145065, without affecting the arterial blood pressure, could revert the decrease of renal or hepatic blood flow to some extent, reduce the water contents of heart, liver, lung, kidney postburn. CONCLUSION: The abnormal changes in endothelins postburn contribute to visceral injury in the early postburn stage in rats.

Animals↗

PubMed1998

[Myocardial contractile and calcium transport function after severe burn injury].

OBJECTIVE: This study examined the changes in myocardial calcium transport function and what roles it played in cardiac dysfunction after severe burn injury. METHODS: Contraction relaxation properties of the left ventricule (LV) were studied in isolated heart preparations of Wistar rat 3, 8, 24 hours after 30% TBSA full thickness burn. Sarcoplasmic reticulum (SR) calcium transport function was measured by millipore filtration technique. RESULTS: The maximal rates of LV pressure elevation (+ dp/ dtmax) and depression (-dp/dtmax) in burn group were significantly lower than that in control group (P < 0.01). The initial rate and capacity of calcium uptake by SR decreased markedly in burn group than in control group (P < 0.01). In addition, calcium dependent ATPase activity and coupling ratio of SR were also markedly depressed. CONCLUSION: SR calcium transport function depression was closely related to cardiac contractile dysfunction, and the former is one of the important mechanism for cardiac contractile dysfunction after severe burn injury.

Animals↗

PubMed1998

[Effects of the serum obtained from smoke inhalation injury rats on PMN adhesion and transmigration in vitro].

OBJECTIVE: This study was conducted to determine the changes in PMN adhesive capacity to endothelial cells and transmigration through endothelial cell (CEC) sheet in the presence of the serum from rats with smoke inhalation injury (SII). The effects of adhesion molecules CD11a, CD11b, and ICAM-1 on the PMN adhesion and transmigration were also studied. METHOD: In the present study fluorescent assay, EC sheet cultured on the 5 microns permeable membrane and antibody blocking technique were used to study the PMN adhesion and transmigration in vitro. RESULT: It was found that the serum from SII rats could promote PMN adhesion to CEC sheet. After being cultured with the serum for 12-24 h, PMN adhesion to CEC was more than three times of that in control. The serum also enhanced PMN transmigration through the CEC sheet in vitro, doubling the amount observed in control when the sheet was cultured with the serum for 24 h. Based on the above data it was believed that the SII rat serum could enhance PMN adhesion to and transmigration through lung capillary, and the percentages of PMN adhesion and transmigration were found to be positively correlated (r = 0.975). Furthermore, the antibodies against CD11a, CD11b, and ICAM-1 reduced PMN adhesion 44%, 55% and 51%, respectively, and at the same time decreased PMN transmigration 39%, 65%, and 58%, respectively. CONCLUSION: In the presence of serum obtained from SII rats PMN adhesion to and transmigration through CEC sheet increased, which is the possible underlying mechanism responsible for PMN infiltration in vitro. Moreover, the adhesion molecules such as CDA11a, CD11b, and ICAM-1 play an important role in the process. Infiltrated PMN could release oxygen free radicals and protease to injure lung tissue.

Animals↗

PubMed1998

[Free jejunal grafts for reconstruction of pharynx and cervical esophasgus].

Eleven patients with hypopharyngeal carcinoma were treated surgically and the pharynx and cervical esophagus were reconstructed with free jejunal grafts through the technique of microvascular anastomosis. The microvascular anastomosis were all successful and the patients all survived the operations. The operations were performed at one time with only a few complications. There were 2 cases of pharyngeal fistula and 1 case of bleeding from the anastomotic site. The patients could eat by their mouths and swallow very well just 15 days after the operation. The 3-year suvival rate was 36%. The main causes of death were the recurrence and the metastasis to the cervical lymph nodes. We came to the conclusion that the operation is safe with high success rate and no mortality during operation, and it is less injurious than the gastropharyngeal anastomosis. The key point of the operation is the surgeon's mastery of the microvascular anastomosis technique.

Aged↗

PubMed1998

[Relationship between nitric oxide synthase, endothelin and the initiation of hypertension and atherosclerosis].

To investigate the relationship between nitric oxide synthase (NOS), endothelin (ET) and the initiation of hypertension and atherosclerosis, 5 hypertensive rats (systemic pressure 22.7-24 kPa), 5 atherosclerotic rats (by cholesterol-rich diet, 3 months), and 5 normal Wistar rats were used for determination of the distribution of NOS and ET of aorta by histochemical methods. The levels determined in the three groups were quantitated and compared by computer-imaging analysis. The results showed that in early stage of atherosclerotic process, the NOS decreased while the ET increased in aorta. In early stage of essential hypertension, however, both NOS and ET levels increased. These results suggest that the increased ET and the change of NOS may play a role in the pathogenesis of hypertension and atherosclerosis.

Animals↗