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Z Yang

Publications and source records attributed to Z Yang.

At least 739 records · Page 41Linked to original sources
PubMed1995

Elevated spontaneous activity of phenylephrine-excited neurons in the caudal ventrolateral medulla of spontaneously hypertensive rats.

1. The caudal ventrolateral medulla (CVLM) of pentobarbital-anaesthetized spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats was identified by the depressor response with microinjection of glutamate. 2. The mean firing rate of the spontaneously active phenylephrine-excited CVLM neurons was significantly greater in SHR than in WKY. The pattern of neuronal firing in terms of coefficient of variation and skewness of the interspike interval histogram was similar in both types of rats. 3. Administration to CVLM of kainic acid, an excitotoxic agent, led to a biphasic blood pressure response--a transient reduction followed by a gradual and sustained elevation. The elevation in blood pressure was significantly greater in SHR than in WKY. 4. These findings suggest that the barosensitive CVLM neurons are more active and the tonic inhibitory influence from CVLM to rostral ventrolateral medulla (RVLM) is greater in SHR than in WKY. It is therefore not likely that the elevated spontaneous activity of the RVLM cardiovascular neurons in SHR is due to a smaller inhibitory influence from CVLM.

Adrenergic alpha-Agonists↗
PubMed1995

CD14 and tissue factor expression by bacterial lipopolysaccharide-stimulated bovine alveolar macrophages in vitro.

The membrane-associated CD14 receptor (mCD14) is a monocyte/macrophage differentiation antigen, and it has been demonstrated to serve as a receptor for bacterial lipopolysaccharide (LPS; endotoxin). Binding of LPS to mCD14 has been shown to be associated with LPS-induced macrophage, monocyte, and neutrophil activation in humans. In this report, we describe the presence and function of an mCD14-like receptor on bovine alveolar macrophages (bAM). An immunofluorescence technique and flow cytometric analysis indicated binding of anti-human CD14 monoclonal antibodies (MAb) My4, 3C10, and 60bd to bAM. Binding of anti-CD14 MAb (3C10 and MY4) was reduced over 20% by pretreatment of bAM with phosphatidylinositol-specific phospholipase C (0.5 to 1.0 U/ml), indicating that bovine mCD14 is a glycosyl phosphatidylinositol-anchored protein. In addition, pretreatment of bAM with anti-CD14 MAb decreased binding of 125I-labeled LPS to macrophages, suggesting that bovine mCD14 serves as a receptor for LPS. A cDNA probe based on the human sequence for CD14 was used in Northern (RNA) blot analysis, and hybridization to human monocyte CD14 yielded the expected 1.5-kb band. Hybridization to bovine mRNA yielded a 1.5-kb band plus an unexpected 3.1-kb band. Constitutive expression of bovine CD14 mRNA was observed, and the expression level was modestly elevated in bAM stimulated for 24 h with LPS (1 ng/ml) in the presence of bovine serum. The function and activation of bAM were assessed by quantitation of tissue factor (TF) expression on the cells using an activated factor X-related chromogenic assay and S-2222 substrate. LPS (1 ng/ml)-mediated upregulation of TF expression on bAM was dependent on the presence of bovine serum components, and TF expression was inhibited by anti-CD14 MAb. In addition, TF mRNA levels in LPS-stimulated bAM were decreased by pretreatment of cells with anti-CD14 MAb (MAb 60bd, 10 micrograms/ml).

Animals↗
PubMed1995

Expression and function of a recombinant PDGF B gene in porcine arteries.

Platelet-derived growth factor (PDGF) B is a mitogen and chemoattractant for smooth muscle cells in vitro, and expression of a recombinant PDGF B gene in porcine arteries stimulates intimal thickening. To define the mechanisms by which PDGF B gene expression induces intimal thickening in vivo, we examined its effects on smooth muscle cell proliferation and migration, extracellular matrix synthesis, and inflammatory cell infiltration in intimal lesions of pig arteries after direct gene transfer of a recombinant PDGF B gene. PDGF B gene expression was associated with rapid formation of an intima, including 3- to 10-fold increases in intimal thickness and intima-to-media area ratio 4 to 21 days after gene transfer compared with control transfected arteries. Intimal smooth muscle cell proliferation was detected at 2 days, peaked at 7 days (P < .01), and declined by 14 days, although the total number of intimal nuclei progressively increased to 21 days (P < .01). Calculations of expected-to-observed ratios of intimal cells, based on BrdC proliferation indexes, demonstrated that the increases in intimal cell number on days 2 through 7 could not be accounted for by proliferation alone, suggesting that recombinant PDGF BB acts to stimulate cell proliferation and migration of smooth muscle cells into the intima. Extracellular matrix deposition and procollagen synthesis were observed after 7 days (P < .01) and were associated with a decline in cell density in the intima, suggesting that extracellular matrix synthesis may contribute to progressive intimal thickening in response to PDGF B gene expression. There was minimal accumulation of inflammatory cells, including macrophages and CD3(+) lymphocytes, in transfected arteries. These data suggest that PDGF B gene expression promotes intimal expansion by both proliferation and migration of smooth muscle cells followed by synthesis of extracellular matrix and therefore acts through several mechanisms to play a role in the pathogenesis of intimal lesions in vivo.

Animals↗
PubMed1995

Overexpression of c-erbB-2 and p21 oncoproteins in human radiation-induced skin ulcers.

We studied the overexpression of c-erbB-2 and p21 oncoproteins in human radiation-induced skin ulcers using immunohistochemistry. We found that the positive rate of overexpression of c-erbB-2 and p21 oncoproteins was 92.0 and 92.9%, respectively. The overexpression of c-erbB-2 oncoprotein was observed mainly in the cell membrane of squamous epithelial cells and in the cytoplasm of fibroblasts, endothelial cells, leiomyocytes in the media, and in fibrocytes of the adventitia of mesenchymal arterioles. The location of the p21 oncoprotein overexpression was mostly similar to that of c-erbB-2 with stronger staining in the cytoplasm of squamous epithelial cells and weaker staining in mesenchymal arteriolar walls. The overexpression of c-erbB-2 and p21 oncoproteins may be corresponding to the cancer transformation and poor healing of radiation-induced skin ulcers.

Humans↗
PubMed1995

[Isolation and identification of a pathogen of grasshoppers].

A pathogen was isolated from natural dead pests of Ceracris kiangsu in Geleshan farm of Chongqin. Its pathogenecity was confirmed by the law of KOCK. It was identified as Pseudomonas pseudoalcaligenes according to its physiological and biochemical properties as well as the G + C content of DNA (63.73mol%). The results of preliminary bioassay show that the pathogen can infect the grasshoppers and Ceracris kiangsu, and also can infect other pests of grassland in a certain extent.

Animals↗
PubMed1995

[Light microscope and energy dispersive X-ray analysis of amalgam pigmentation].

24 cases of amalgam pigmentation were analyzed by light microscope. 16 cases were amalgam debris, 8 cases were amalgam fragments and debris mixed. The amalgam distributed mainly along basement membrane of the epithelium, wall of blood vessels, nerve fibers, reticular fibers and endomysiums. In case where amalgam entered the bone, bone cells disappeared, lacuna emptied and microfracture of bony trabecullae occurred. In 8 cases pathologic calcification were found and in 18 cases there were inflammatory responses. 2 cases were analyzed by energy dispersive X-ray. It was found that in the different sites of tissues there were different content of Ag, Hg, Sn and Ca.

Adolescent↗
PubMed1995

[Causes of postoperative recurrent varicose veins of lower extremities].

We analysed venograms of recurrent varicose veins in 180 cases (206 lower limbs). Deep vein valvular insufficiency resulted in varicose veins in 52.9% cases, and post-thrombotic syndrome in 18.9%. The causes of postoperative recurrent varicose veins varied: blindly performed single superficial veins operation, low ligation of the long saphenous trunk, incomplete stripping of varicose veins, missing of the short varicose saphena or incomplete ligation of the perforating veins and failure of deep vein valvular repairs. Venography is of value in making correct diagnosis and choosing appropriate operations.

Adult↗
PubMed1995

Thrombin increases expression of urokinase receptor by activation of the thrombin receptor.

PURPOSE: To investigate the effect of thrombin on the urokinase plasminogen activator receptor (u-PAR) in retinal pigment epithelial (RPE) cells. METHODS: The authors analyzed u-PAR mRNA by Northern blot hybridization. Retinal pigment epithelial cell surface u-PAR was assayed by measuring the amount of functional urokinase plasminogen activator (u-PA) bound to cells at saturation. Retinal pigment epithelial cells were derived from fetal retinal tissue and established in primary cell culture. RESULTS: Thrombin increased u-PAR mRNA 4-fold in RPE cells examined by Northern blot hybridization, whereas the amount of thrombin receptor mRNA was unchanged. Thrombin stimulated u-PA binding to RPE cells 2.5- to 5-fold in a time- and dose-dependent manner. Hirudin, a thrombin antagonist, completely blocked the effects of thrombin on u-PAR expression in RPE cells. Phosphatidylinositol phospholipase C treatment of RPE cells resulted in the abolition of thrombin-induced u-PA binding. Recombinant soluble u-PAR competitively inhibited two-chain u-PA binding to the surface of thrombin-treated RPE cells. A thrombin receptor agonist peptide (SFLLRNPNDKYEPF) also induced a 2.5-fold increase in binding of u-PA to the surface of RPE cells. CONCLUSION: Thrombin increases u-PAR expression by RPE cells by a mechanism involving activation of the seven transmembrane thrombin receptor.

Amino Acid Sequence↗
PubMed1995

Prognostic efficacy of troponin T measurement in angina pectoris.

This study was designed to evaluate the efficacy of the newly developed Troponin T (TNT) enzyme immunoassay for predicting the prognosis of patients with angina pectoris. TNT, creatine kinase (CK) and MB isoenzyme of creatine kinase (CK-MB) were monitored in 134 patients with angina pectoris. There was no abnormality with any of these tests in 40 patients with stable angina pectoris and 30 patients with unstable angina pectoris of Class 1 and 2 according to Braunwald's criteria. None of them developed acute myocardial infarction or other cardiac events. Elevation of TNT concentration with normal level of CK and CK-MB was found in 34 of the 64 cases of unstable angina pectoris of Class 3. Among the 34 patients, 11 had acute myocardial infarction within 10 days during hospitalization. In contrast, only one of the patients with unstable angina pectoris of Class 3 with normal value of TNT developed acute myocardial infarction. As the incidence of angina pectoris is quite high clinically but only a small number of patients developed myocardial infarction, it is necessary to have a new assay of high sensitivity and high negative predictive value. TNT determination could meet these requirements as it had high sensitivity (92%) and high negative predictive value (98%) for the prognosis of unstable angina pectoris. If there is no rise of circulating TNT level, a favorable outcome can be expected with a high degree of probability. Determination of serum TNT level would be adopted as a routine procedure for evaluating the prognosis of angina pectoris and it is superior to other enzyme tests such as CK and CK-MB.

Adult↗
PubMed1995

[Experimental observations of the quantitative changes of proteoglycan in homogenous cartilage graft in the guinea pig].

The present work was to study the quantitative change of proteoglycan (PG) in homogenous cartilage graft in the guinea pig. Histological, histochemical and biochemical studies were undertaken at different times after grafting. The results revealed that there was a marked reducing trend of matrix PG within four weeks after grafting. Four weeks afterwards all indexes except hexuronic acid restored slowly and approached the level of the control group. By the 20th week, the activity of neutromucopolysaccharide, hexosamine, acid-mucopolysaccharide and alkaline phosphatase restored to 73.6% -93.7% of the control group (P > 0.05). The changes probably were caused by immune reaction and operative trauma. PG in the cartilage matrix forms a barrier for the chondrocytes, protecting the host's immune system from contacting and reacting with the chondrocytes of the graft. Though the core protein of PG has antigenicity, it is surrounded by acidmucopolysaccharide that has no antigenicity. We concluded that it is very important to maintain a high level of PG in order to prolong the survival of a cartilage graft.

Animals↗
PubMed1995

[Immunohistochemical study of epidermal growth factor in liver of mice infected with schistosoma japonicum].

In this immunohistochemical study we examined the expression and localization of the epidermal growth factor in liver of mice infected with schistosoma japonicum during regulatory phase of immunology and early phase of hepatic fibrosis. EGF immunostaining is localized along sinusoids and within cytoplasm of centrilobular area and around ova granuloma at 6,8 weeks of infection. Proliferation of Ito cells and collagen deposition in Disse space were found by electron microscope. The data led us to conclude that the ova depositing in liver could excite the release of EGF and cytokines, then promote proliferation of Ito cells and overgrowth of extracellular matrix (ECM) under the endothelium, resulting in hepatic fibrosis.

Animals↗
PubMed1995

Mixed model analysis of DNA sequence evolution.

Nucleotides in a DNA sequence may be changing at different rates, because they are located in different structural and functional regions of the gene, and are thus subject to different mutational pressures or selective restrictions. Knowledge of substitution rates at specific sites is important for understanding the forces and mechanisms that have shaped the evolution of the DNA sequences. The gamma distribution has previously been proposed to model such rate variation among nucleotide sites. Based on mixed model methodology we present in this paper a method for predicting substitution rates at nucleotide sites by using homologous DNA sequences. The predictor is unbiased and "best" in the sense that it minimizes the mean squared error and maximizes the correlation between the predictor and the true value. It is also quite robust to errors in estimates of parameters in the model. A numerical example is given, with guidelines for the practical use of the approach. The most influential factor affecting the accuracy of prediction is the number of sequences; to get a correlation of over .7 between the predictor and the true value, about six to seven sequences are needed, depending on the overall similarity of the sequences.

Animals↗
PubMed1995

A 32-year-old woman with pain and swelling at the base of her thumb.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Adult↗
PubMed1995

Encircling suture method in the treatment of femoral venous valvular incompetency.

Many patients with chronic venous insufficiency syndrome caused by the "relative valvular incompetency" with venous dilatation. Eighty-six per cent of the cases can be cured by reducing the femoral venous diameter by simply using the encircling suture method just distal to the first femoral valvular sinus. Our preliminary results suggest that such a method of surgical treatment is simple and efficient.

Adult↗
PubMed1995

A 9-year-old girl with swelling and pain in the leg.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are presented on this page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Bone Neoplasms↗