Biomedical subjects

Z Yang

Publications and source records attributed to Z Yang.

At least 703 records · Page 39Linked to original sources

PubMed1996

[Dynamic changes of endothelin in sera of rats at early burn stage and its effects on endothelial cell permeability in vitro].

The dynamic changes of endothelin in sera of early burnt rats and the effects of endothelin-1 on the permeability of vascular endothelial cells were investigated. In the early phase of 30% (II degree) total body surface area (TBSA) burn rat model, we measured the concentration of endothelins in plasma, the water contents in main organs and the permeability of endothelial monolayer cultured on micropore membrane to Hank's solution or 5 g/L albumin Hank's solution. Endothelin concentration in burnt rat sera was firstly increased dramatically, showing a peak at 6 hours postburn, and then remained significantly higher than the basic level (P < 0.01). The changes of endothelin were correlated with the alteration in water contents in main organs after burn. Moreover, if the cultured endothelial cells were exposed to 0, 1, 10, 100 nmol/L endothelin 1 for 60 min, it was found that the filtration volume (Jv) and the filtration coefficient (Kf) of endothelial monolayer were significantly enhanced as determined by either Hank's or albumin (5 g/L) perfusion, while the osmotic reflection coefficient (sigma) (to protein) decreased in a dose-dependent pattern. The present results suggest that the postburn elevated endothelin may not only mediate the blood flow distribution via potent vasoconstriction, but also directly increase the vascular permeability. The mechanism(s) of the latter event needs to be further clarified.

Animals↗

PubMed1996

[Determination of placental alkaline phosphatase (PLAP) for detecting the damages of alveolar type I cells caused by smoke inhalation].

The placental alkaline phosphatase (PLAP) is a marker enzyme of alveolar type I cells. To evaluate the damages of alveolar type I cells and its relations with the development of acute lung injury caused by smoke inhalation, the present study was designed to observe the dynamic changes in PLAP contents in plasma and bronchoalveolar lavage fluid (BALF). Following the induction of smoke inhalation injury in rat, the arterial blood gas levels, lung water volume, total protein and albumin contents in BALF, and PLAP contents in plasma and BALF were determined respectively in normal control and injured animals at 2, 6, 12 and 24 h after injury. The pathomorphology of lung tissues was also observed. It was found that after smoke inhalation, animals showed acute respiratory failure and serious pulmonary edema. The total protein and albumin levels in BALF increased markedly. Both PLAP contents in plasma and BALF also increased dramatically, and there was a significant positive correlation between the changes in the PLAP and the total protein contents in BALF. The pathomorphologically serious structural damage of alveolar type I cells were also found. PLAP may be not only a marker of alveolar type I cells injury, but also interrelated with the permeability increase of alveolar-capillary membrane after smoke inhalation.

Alkaline Phosphatase↗

PubMed1996

[Multiple organ failure in burn patients combined with inhalation injury].

To define the clinical features and prevention and treatment of multiple organ failure (MOF) developed in burn patients combined with inhalation injury, a retrospective clinical study on 4834 burn patients admitted into the Institute from Jan, 1977 to Aug, 1991, in which 366 cases sustained inhalation injury, was performed. It was shown that postburn MOF occurred in 115 cases among the 4834 victims, with an incidence of 2.38%. However, of the 366 cases with inhalation injury 76 were complicated with MOF, an incidence as high as 20.77%, approximately occupying two-thirds of the postburn MOF. The incidence and mortality of MOF were higher when there was inhalation injury. It occurred earlier. More respiratory complications, higher incidence of lung and cardiac failure as well as severe shock were observed. Moreover, hypoxemia and acidosis were found to be more severe in MOF patients with inhalation injury than those without. It is suggested that good control of inhalation injury and burn shock, as well as the ischemic-hypoxic damage of visceral tissues might be of great importance for the prevention and treatment of MOF in burn patients combined with inhalation injury.

Adult↗

PubMed1996

[Monocellular quantitative study on the adhesive ability of eosinophils in the course of eosinophils activation].

OBJECTIVE: To observe the dynamic changes of eosinophils (EOS) adhesive ability in the course of eosinophils activation. METHODS: The adhesive ability EOS to vascular endothelial cell (EC) was measured by the use of a microminpulation technique. RESULTS: The critical separation stress (Sc) between rest EOS and EC was 0.61 +/- 0.07kPa. Treatment of EOS with platelet activaty factor (PAF) caused a significant increase in Sc. The Sc was 4.1 +/- 0.6kPa within 30 minutes of EOS exposure to PAF, and had no tendency to increase continuously by exposure time prolonged. CONCLUSIONS: The increase of EOS adhesive ability belongs to a kind of rapid response while EOS is activated. The increase could be an important basis of EOS adhesion to EC and EOS entry into bronchial mucosa.

Cell Adhesion↗

PubMed1996

[Establishment of cervical lymph node metastasis in model rats and its microcirculation characteristics].

To determine the effects of vasoactive agents on blood flow in lymph node metastases, the blood flow in the cervical lymph node metastases and normal tissue were meassured using a hydrogen clearance method, at normotensive state, angiotensin I (A I) induced hypertensive state and sodium nitroprusside (SNP) induced hypotensive state. The metastases occurred frequently in the cervical lymph nodes of 17 rats on day 11-14 after Yoshida ascites hepatoma. AH109A cells were subcutaneously inoculated into back of auricule of 20 rats. The blood flow in the liver, brain and bone marrow of normal rats was of no significant changes when the mean arterial blood pressure (MABP) was elevated to approximately 20 kPa by infusion of A I and decreased to approximately 9.06 kPa by infusion of SNP. But the blood flow in the metastatic lymph nodes was increased from 1.42 +/- 0.48 ml.kg-1/s to 3.45 +/- 1.33 ml.kg-1/s (n = 13, P < 0.05) when the MABP was elevated from 14.81 +/- 1.04 kPa to 18.93 +/- 0.92 kPa by A I. On the contrary, the blood flow in the metastatic lymph node was decreased to 0.55 +/- 0.25 ml.kg-1/s (n = 13, P < 0.05) when the MABP was decreased to 8.84 +/- 0.63 kPa by SNP. The results indicated that microcirculation characteristics in the cervical lymph node metastases were different from those in the normal tissues. A I induced hypertension was useful to selectively improve delivery of chemotherapeutic drugs to the site of metastases. On the other hand, SNP induced hypotension may be useful to suppress washout of the drugs.

Animals↗

PubMed1996

[Pathology of endothelium, extracellular matrix and smooth muscle in gastric coronary vein of cirrhotic patients].

Immunohistochemical stain was used to observe the pathology of endothelium, extracellular matrix (ECM), vascular smooth muscle cell (VSMC) in gastric coronary vein of 30 cirrhotic patients and 10 controls. There was widespread destruction to endothelium, intravenous thrombosis, aggregation of pericyte, smooth muscle hyperplasia, and increased FN, LN, collagen IV and smooth muscle actin in the wall of the coronary vein in cirrhotic patients. The thickness of the wall and its smooth muscle were 3.07 +/- 1.03 mm and 2.31 +/- 0.76 mm respectively in cirrhotic patients, and 1.65 +/- 0.49 mm and 0.88 +/- 0.20 mm in non-cirrhotic patients (P < 0.01). Based on these observations a new concept of portal hypertensive vasculopathy was put forward.

Adult↗

PubMed1996

[Preparation of fumitremorgin B].

In order to prepare fumitremorgin B (FTB), strains of Aspergillus fumigatus C4104 and 3656 were selected, based on the screening of high-FTB-production strains, and inoculated in rice medium of five kilograms and incubated for producing toxin. Cultures were extracted with ethyl acetate, dehydrated with anhydrous sodium sulfate, defatted with n-hexane, decolorized with activated charcoal, chromatographed in silica gel H column, recrystallized by methanol, and finally, four grams of colorless fine-needle shaped crystal were harvested. Two strains of the fungus could produce 800 mg of toxin per kilogram rice medium in average with a yield of approximately 20%, much higher than that reported in literatures (1.11%). Indentification with chemical analysis, such as melting point, ultraviolet, infrared, elemental analysis, mass spectrometry, as well as analyses of nuclear magnetic resonance hydrogen spectrum and carbon spectrum, showed consistency of the results with those in literatures, and confirmed it contained FTB with one molecule of H2O. Contribution of carbon and hydrogen to the molecular structure of self-prepared FTB was explored in the paper based on the spectrometric data.

Aspergillus fumigatus↗

PubMed1996

[The role of amylase in abdominal fluid in evaluating severity of acute pancreatitis and its prognosis].

Acute pancreatitis (AP) was induced on 22 cats, by injecting the mixture of bile and trypsin at different doses into the main pancreatic duct (MPD). In Group A, 7 cats revealed pancreatic interstitial edema after the injection of the mixture at 0.8 mg/kg. In Group B, 8 cats received the injection of the MPD at 1.0 mg/kg which resulted in significant extensive necrosis of the pancreas. The same pathological change was found in Group C (7 cats), combined with lesions of the lung and the liver. The survival time was different, more than 7 days in Group A, 50.4 hours in Group B and 10.4 hours in Group C (P < 0.001). Amylase concentration also showed marked difference in different groups, 4,890 U/L in Group A; 13 952 U/L in Group B and 23,810 U/L (P < 0.001) in Group C. These results are directly proportional to the severity of AP, but inversely proportional to the survival time. It suggests that amylase concentration in abdominal fluid can be used as an important marker to evaluate the severity of AP and its prognosis.

Acute Disease↗

PubMed1996

[Inotropic effect of novel cardiotonic agent, vesnarinone--tests on anaesthetized dogs].

We studied the positive inotropic effect of the novel cardiotonic agent, vesnarinone on open chest and intact anaesthetized dogs hearts. The results indicate that vesnarinone has a dose-effect relationship on increasing the contractile force, LV dp/dt max and stroke volume, and it shortens the ejection time 21%. No effect on blood pressure and heart rate was noted. Vesnarione is more effective than amrinone in terms of positive inotropic effect.

Animals↗

PubMed1996

Gene transfer approaches to the regulation of vascular cell proliferation.

Considerable progress has been made in identifying potential targets for treating vascular proliferative diseases. In this review, we discuss gene transfer approaches to regulating smooth muscle cell proliferation after vascular injury using the cell cycle specific proteins, p21, delta Rb and HSV-tk. Results from these studies suggest that replicating smooth muscle cells and macrophages are inhibited in vivo in several animal models of restenosis, including hyperlipidaemic vessels. Identification of appropriate vascular diseases and improvements in gene delivery and vectors will require careful optimization in order to develop effective molecular therapies for human vascular diseases.

Animals↗

PubMed1996

[Tuberculosis of the pancreatic head].

Eight patients with tuberculosis of the head of the pancreas were retrospectively reviewed. They were 4 men and 4 women (mean age 42.8 years). All patients complained of fever, sweating, fatigue, weight loss, and in the pain in the upper right belly. Abdominal mass was noted in 4 patients, jaundice in 3, and splenomegaly with hypersplenism in 4. Among the 8 patients, 5 suffered tuberculosis of the pancreas before the operation. All of them received laparotomy. Pancreatic tuberculosis in the all patients was confirmed by pathologically. Tuberculosis abscess was drained operatively. Antituberculosis therapy was available for all patients after the operation.

Adult↗

PubMed1996

[Estradiol receptors expression in nasal polyps and its significance].

Nasal polyps are generally considered as a result of extreme nasal mucosal edema induced by long-term recurrent inflammation of the respiratory mucosa. The estradiol (E2) has been demonstrated to play a facilitating role in nasal inflammation. To evaluate the effect of estradiol on the pathogenesis of nasal polyps, the expression of E2 receptors in paraffin section from patients with nasal polyps (84 cases), chronic hypertrophic rhinitis (6 cases) and healthy control subjects were investigated by means of immunohistochemistry for E2 receptors and toluidine blue staining for mast cells. It was shown that there was high expression of E2 receptors in 61 out of 84 cases (male 40, female 44) of nasal polyps and the expression distributed equally among both sexes. Low expression of E2 receptors presents in 2 out of 6 cases of chronic rhinitis and 1 out of 4 healthy subjects. Noteworthily, the E2 receptor expressing cells are similar with the mast cells in shape and distribution. The authors speculate that they may be identical cells. E2 receptor expression in nasal polyps suggests that estradiol plays certain role in the development of nasal polyps.

Adult↗

PubMed1996

[Resection of cranial base tumors].

This article reports 10 cases of cranial base tumors resected by pre-or retro-auricular intratemporal approach. Among them four were neuronomas, two meningiomas, one malignant giant cell tumor of bone, one osteochondnoma, one parotid mixed neoplasm and one poorly-differentiated squamors cell carcinoma. Total resection in 9 cases and one subtotal resection were performed without operative mortality and serious surgical complications. The surgical management of cranial base tumor and indications for selecting operative approaches were discussed.

Adult↗

PubMed1996

[Changes of chemical constituents of radix Sophorae flavescentis in complex formulas of traditional Chinese medicine].

Experiments have been made on the changes of chemical constituents in complex formulas of traditional Chinese medicine. The results show that in the complex formula containing Radix Sophorae Flavescentis, as affected by various conditions of processing such as water, temperature and coexisting reductive substances, the content of oxymatrine tends to decrease gradually to disappear while that of matrine increase gradually.

Alkaloids↗

PubMed1995

[Molecular medicine and gene therapy as exemplified with arteriosclerosis and restenosis].

Atherosclerosis and its consequences account for most morbidity and mortality in Western countries. Atherosclerosis develops over a period of decades and has a complex pathogenesis. It is a disease of the intima and primarily involves four cell types, i.e. endothelial and vascular smooth muscle cells, monocytes and platelets. In recent years, elucidation of the cellular and molecular mechanisms of these cells, and their alterations by cardiovascular risk factors and in atherosclerosis, has markedly expanded knowledge of this disease. In particular, it became clear that endothelial cells play a crucial role in the regulation of platelet function and coagulation, as well as vascular tone and structure. Interestingly, endothelial dysfunction occurs early on in the presence of cardiovascular risk factors such as hyperlipidemia, hypertension and diabetes. This could lead to adhesion of circulating platelets and monocytes, increased accumulation of lipids in the subintima, increased contraction, migration and proliferation of vascular smooth muscle cells. The fact that atherosclerosis develops only in some but not in other parts of the circulation, however, has rarely been considered. With the development of molecular biology it has now become possible to clone differentially expressed genes in vessels with or without atherosclerosis; this in turn makes it possible to characterize better the molecular and cellular mechanisms of the disease. The search for such candidate genes could form the basis for future genetic interventions. This therapeutic approach is likely to assume clinical importance, particularly in monogenetic diseases (i.e. familial hypercholesteremia), while its use in complex polygenetic diseases such as atherosclerosis is more difficult. Restenosis, however, may be accessible to gene therapy earlier on as it is accessible to local gene transfection.

Arteriosclerosis↗

PubMed1995

Restoration of phosphorylation-dependent regulation to the skeletal muscle myosin regulatory light chain.

Regulation of the ATPase activity of smooth and nonmuscle myosin II involves reversible phosphorylation of the regulatory light chain (RLC). The RLC from skeletal muscle myosin (skRLC) is unable to confer regulation (myosin is locked in an inactive state) to smooth muscle myosin when substituted for the endogenous smooth RLC (smRLC). Studies of chimeric light chains comprised of the N- or C-terminal half of each skRLC and smRLC suggest that the structural basis for the loss of this regulation is within the C-terminal half of the RLC (Trybus, K.M., and Chatman, T.A. (1993) J. Biol. Chem. 268, 4412-4419). The purpose of this study is to delineate the structural elements within the C-terminal half of the smRLC that are absent in the skRLC and are necessary for regulation. By sequence comparison, six residues, Arg-103, Arg-123, Met-129, Gly-130, Arg-143, and Arg-160, which are conserved in regulated myosin RLCs but missing in nonregulated myosin RLCs, were identified in smRLC. To test whether these amino acids provide the missing structural elements necessary for phosphorylation-mediated regulation, a skRLC was engineered that replaced the corresponding skRLC amino acids (positions 100, 120, 126, 127, 140, and 157, respectively) with their smRLC counterparts. Using a newly developed RLC exchange procedure, the purified mutant protein was evaluated for its ability to regulate chicken gizzard smooth muscle myosin. Substitution of the six conserved amino acids into the skRLC completely restored phosphorylation-mediated regulation. Thus, a subset of these amino acids, including four basic arginine residues located in the E, F, G, and H helices which are missing in skRLC, may be the structural coordinates for the phosphorylserine in the N terminus. Based on this result, the regulation of glycogen phosphorylase is discussed as a model for the regulation of smooth muscle myosin.

Amino Acid Sequence↗

PubMed1995

Glutamate enhances the adenylyl cyclase-cAMP system-induced beta-endorphin secretion and POMC mRNA expression in rat hypothalamic neurons in culture: NMDA receptor-mediated modulation.

L-Glutamate, a major excitatory amino acid of the central nervous system, plays important roles as neurotransmitter and neuromodulator in the brain. Increasing evidence suggests that glutamate may also involve in the regulation of the neuroendocrine system at the hypothalamus. Employing long term monolayer hypothalamic cell cultures prepared from neonatal rats, we reported here that whereas glutamate significantly enhanced forskolin-, or N6,2'-O-dibutyryladenosine-3'5'-cyclic monophosphate [(Bu)2cAMP]-stimulated immunoreactive (ir)-beta EP release from cultures treated daily for 4 consecutive days, the excitatory amino acid alone produced little effect. This potentiation of glutamate was time-related and dose-dependent with an Emax value of the amino acid being approximately 50 microM; at this concentration glutamate augmented ir-beta EP secretion about 1.8 times (P < 0.05) that induced by 2 microM forskolin alone. Similar effects were also observed for POMC mRNA levels in cultures subjected to 6 h of the above treatment regime. This potentiating effect of glutamate appears to be mediated specifically through NMDA receptor as it can be mimicked by NMDA but not by kainic acid or quisqualic acid, and blocked by the NMDA receptor antagonist 2-amino-5-phosphonovalerate (APV), but not by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA glutamate receptor antagonist. Interestingly, glutamate was found not to enhance high doses of forskolin (10 microM) or (Bu)2cAMP (100 microM) stimulated beta EP release and POMC mRNA levels in hypothalamic cell cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗

PubMed1995

Incorporation of 5-bromo-2'-deoxyuridine into colorectal liver metastases and liver in patients receiving a 7-day hepatic arterial infusion.

Preclinical and clinical data suggest that the combination of hepatic arterial bromodeoxyuridine (BrdUrd), a thymidine analogue radiation sensitizer, and high-dose three-dimensional conformal radiation therapy offer a high potential for improving the local control of intrahepatic cancers. A key step in the design of a successful protocol is to determine in patients the conditions for BrdUrd administration that would be expected to produce selective radiosensitization of the tumor. Therefore, we designed a clinical trial to assess BrdUrd incorporation into the DNA of hepatic colorectal metastases and normal liver after a 7-day continuous BrdUrd infusion at a dose rate of 25 mg/kg/day (the maximal tolerated dose for a 14-day infusion) for patients undergoing laparotomy for either resection of liver metastases or hepatic arterial catheter and pump placement. Thirteen patients were entered into this study. We found that the average replacement of thymidine by BrdUrd in the tumor and normal liver were 11.6 +/- 1.2% and 1.1 +/- 0.2%, respectively. This extent of incorporation would be expected to produce a single fraction radiation enhancement of 1.5 in the tumor without detectable sensitization of the normal liver. Immunohistochemical staining for BrdUrd revealed heterogeneity of incorporation with a range of approximately 60-80% of the cells labeled in different regions of the specimens. These findings suggest that hepatic arterial BrdUrd given at this dose and schedule has a high likelihood of producing clinically significant radiosensitization for patients with hepatic metastases from colorectal cancer. Furthermore, the demonstrated selectivity of tumor perfusion that can be obtained with hepatic arterial infusion combined with the high proliferative rate of colorectal metastases (versus normal liver) suggests that these patients may be good candidates for tumor-directed gene transfer therapy by using regionally delivered retroviral vectors.

Adult↗