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Biomedical subjects

D Cheng

Publications and source records attributed to D Cheng.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Acute effect of milrinone on pulmonary hemodynamics in patients with hypoxic pulmonary hypertension].

Milrinone is a phosphodiesterase inhibitor that has vasorelaxant activity. The authors studied its effect on pulmonary haemodynamics in 12 patients with hypoxic pulmonary hypertension. After treatment with milrinone, mean pulmonary arterial pressure (from 4.61 +/- 1.41 kPa to 3.36 +/- 1.20 kPa, 1kPa = 7.5mmHg) and pulmonary vascular resistance (from 557.56 +/- 167.70 dyne.sec.cm-5 to 392.60 +/- 133. 81 dyne.sec.cm-5) decreased (P < 0.05), while cardiac output increased (from 5.11 +/- 1.62 L/min to 5.62 +/- 1.66 L/min) (P > 0.05). The systemic blood pressure (from 11.50 +/- 1.63 kPa to 10.71 +/- 1.83 kPa) and systemic vascular resistance (from 1476.64 +/- 531.52 dyne.sec.cm-5 to 1,236.49 +/- 410.18 dyne.sec.cm-5) also decreased (P > 0.05). but there was no change in arterial oxygen saturation (SaO2). The incidence of side effects were low, 4 patients developed tackycardia, and 2 patients developed ventricular premature beats. It is therefore, shown that milrinone is a potent pulmonary vasodilator.

Aged↗
PubMed1995

[Acute effects of platelet activating factor on the pulmonary circulation in rats].

To investigate the acute effects of platelet activating factor (PAF) on pulmonary circulation and cardiovascular function in rats, twenty anesthetized Wistar rats were given 100-800 ng/kg PAF by bolus intrapulmonary artery infusion. Mean pulmonary artery pressure (mPAP), mean systemic artery pressure (mSAP) and cardiac output (CO) were measured before and after administration. The results showed that PAF infusion caused: a rise in mPAP from 2.11 +/- 0.20 kPa to 2.65 +/- 0.11 kPa (100 ng/kg, P > 0.05), from 2.32 +/- 0.25 kPa to 2.85 +/- 0.24 kPa (200 ng/kg, P < 0.05) and from 2.11 +/- 0.33 kPa to 3.01 +/- 0.45 kPa (400 ng/kg, P < 0.05)p; a down in mSAP from 16.0 +/- 2.11 kPa to 9.1 +/- 2.39 kPa (100 ng/kg, P < 0.05); from 16.3 +/- 1.38 kPa to 7.0 +/- 0.57 kPa (200 ng/kg, P < 0.05) and from 16.4 +/- 2.56 kPa to 6.3 +/- 0.89 kPa (400 ng/kg, P < 0.05); and a down in CO from 48.1 +/- 2.16 ml/min to 30.8 +/- 3.27 ml/min (100 ng/kg, P < 0.05), from 47.8 +/- 2.12 ml/min to 25.6 +/- 2.86 ml/min (200 ng/kg, P < 0.05) and from 48.3 +/- 2.24 ml/min to 20.0 +/- 2.39 ml/min (400 ng/kg, P < 0.05). These findings suggested that PAF play an important role in the pathophysiologic course of pulmonary hypertension.

Animals↗
PubMed1995

[The delayed traumatic intracerebral haematomas].

The results of CT observation of 378 inpatients with head injury were reported. 46 delayed traumatic intracerebral haematomas (DTICH) patients were found to have 71 haematomas. The incidence of DTICH was 12.2%. 80.7% of DTICH patients were noted 48 hours after injury. Most of them were young and middle aged persons. The places of baematomas were at the injured zones. The intracranial pressure continous monitor is useful to judge the DTICH during the early stage. Surgical operation is proposed for the patients with many haematomas and displaced central tissue. The haematomas should be cleansed for the frequently occurring haematoma patients. The death rate of the example was 17.4%, which was lower than 44%-71% reported elsewhere.

Adolescent↗
PubMed1995

[Distribution of platelet activating factor in the pulmonary tissues of normal rats].

Platelet activating factor (PAF) is a biologically active phospholipid with a broad range of cellular targets and respective responses. Because lung homogenates obtained from normal rats contain measurable levels of PAF, it may be involved in both pathological and physiological processes of lung. In this study, we have searched for the distribution of PAF in the rat lungs by immunohistochemistry. We demonstrated that PAF immunoreactivity is present on pulmonary arterial and alveolar walls. The results showed that PAF are located in pulmonary arterial and alveolar wall under normal condition, and that PAF may play a role in maintaining pulmonary physiological process.

Animals↗
PubMed1995

[Effect of tetrandrine on pulmonary hypertension induced by monocrotaline in rats].

The effects of Tetrandrine (Tet) on intraacinous pulmonary arteries (IAPA) and bemodynamics were studied by means of a rat pulmonary hypertension model induced by monocrotaline. The results showed that Tet could reduce the contractive pressure of pulmonary artery, right ventricle and right atrium of heart by 28.0%, 28.3%, and 31.5% respectively. It could also decrease the vascular degeneration of endoepithelial cells of IAPA, the endoepithelial subcavity, the collagens of medial membrane and the numbers of smooth muscles of IAPA.

Alkaloids↗
PubMed1995

[Effects of ginkgolide B on isobaric hypoxic pulmonary hypertension in rats].

We examined the effects of ginkgolide B (BN52021), a specific platelet activating factor (PAF) antagonist, on hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling. Chronic hypoxia can cause pulmonary hypertension and pulmonary vascular remodeling in rats. Treated with BN52021, the rat's pulmonary hypertension, pulmonary vascular remodeling and right ventricular hypertrophy at 3 weeks of hypoxic exposure (FiO2 = 0,10) could be reduced. The results suggest that PAF contributes to the development of chronic hypoxic pulmonary hypertension and pulmonary vascular remodeling, and PAF antagonist may be an useful agent for preventing hypoxic pulmonary hypertension.

Animals↗
PubMed1994

Hepatitis delta virus replication in vitro is not affected by interferon-alpha or -gamma despite intact cellular responses to interferon and dsRNA.

The hepatitis delta virus (HDV) genome consists of circular ssRNA which has extensive intramolecular complementarity and can form a dsRNA rod-like structure. If such RNA species were to exist in an unmasked form in cells, they would be expected to induce interferon (IFN) expression and activate two IFN-inducible dsRNA-dependent enzymes with anti-viral activity, namely the dsRNA-dependent protein kinase (PKR) and 2',5' oligoadenylate (2',5' A) synthetase. Since the virus replicates to high copy number for prolonged periods in infected cells it is apparently able to evade these antiviral mechanisms. The RNA genome may be masked and fail to induce or activate the antiviral response, or the virus may inhibit such a response. Treatment of a hepatoma cell line, Huh7, and a fibrosarcoma cell line, HT1080, stably transfected with a trimeric HDV cDNA construct, with IFN-alpha or IFN-gamma for up to seven days failed to influence the level of expression of genomic or antigenomic HDV RNA, or delta antigen (Ag). This is consistent with either failure of activation or inhibition of the IFN response. However the induction of several IFN-responsive genes, including PKR, 2',5' A synthetase and class I MHC is normal and cotransfection of a construct expressing delta Ag did not affect expression from an IFN-inducible chloramphenicol acetyltransferase construct. In addition, the activation of PKR is not inhibited in HDV-expressing cells and antiviral assays suggest that the ability of these cells to mount an antiviral response to at least two cytopathic viruses is unaffected. IFN-beta is inducible normally by dsRNA in cells transfected with the delta cDNA trimer. We conclude that HDV replication is not inhibited by IFN-alpha or IFN-gamma, even though the responses of cells expressing HDV RNA and antigen to IFN and dsRNA are intact.

2',5'-Oligoadenylate Synthetase↗
PubMed1994

High density cultivation of a recombinant CD-1 cell line producing prourokinase using a Biosilon microcarrier culture system.

CD-1, a genetically-engineered CHO cell line, was cultivated with a Biosilon microcarrier culture system. We successfully cultivated CD-1 cells to a very high density (over 1 x 10(7) cells/ml). Prourokinase was stably secreted at about 180 IU/10(6) cells/24 h. Experiments showed that CD-1 cells growing on Biosilon microcarriers were able to spontaneously release from the microcarriers, then reattach and proliferate on fresh microcarriers. This makes it very easy to scale up production. The microcarriers could be reused several times without affecting adhesion, proliferation and prourokinase secretion. With CM-PECC membrane radial flow chromatography and MPG chromatography, the prourokinase in conditioned medium could be purified to a specific activity of 1 x 10(5) IU/mg of protein. The purification factor was about 600 fold, and approximately 90% of the biological activity was recovered.

Animals↗
PubMed1994

[Clinical application of neurovascular island flap in the hand].

From 1962 to 1992, four kinds of neurovascular island flaps of the hand were used for the treatment of skin defects in the hand in 72 cases. Of these flaps, 38 were pulp flaps of the finger, 24 were based on the first dorsal metacarpal artery, 7 were from second dorsal metacarpal artery and 3 were from hypothenar area. All the flaps survived except 1. Postoperative follow-up showed excellent or good results in 94.4%. The indications of the operation, flap design and surgical procedure are described. The anatomical feature, the advantages and disadvantages of the flap are discussed.

Adolescent↗
PubMed1994

Terpenoid glycosides from the roots of Aster tataricus.

A new monoterpene glycoside, shionoside C, and a new oleanane-type triterpene glycoside, aster saponin G, were isolated from the roots of Aster tataricus. Their structures were elucidated on the basis of spectral and chemical methods. Shionoside C is L-endo-camphanol-8-3,5-isopropylidene-beta-D- apiofuranosyl-(1-6)-beta-D-glucopyranoside, aster saponin G is 3-O-[O-alpha-L-arabinopyranosyl-(1-6)-beta-D-glucopyranosyl]-2 beta, 3 beta, 16 alpha-trihydroxyolean-12-en-28-oic acid (asterogenic acid) 28-[O-beta-D-xylopyranosyl-(1-4)-alpha-L- rhamnopyranosyl-(1-2)-beta-D-xylopyranosyl]ester.

Bridged Bicyclo Compounds↗
PubMed1993

High level expression of human prourokinase cDNA in Chinese hamster ovary cells.

We have used Chinese hamster ovary (CHO) cells to express high levels of human prourokinase gene cDNA with recourse to construction of good expression vector, the improvement of transfection technique and gene coamplification. First, we constructed expression plasmid pMG10102 by placing pro-UK cDNA under the control of SR alpha promoter/SV40 polyadenylation signals and expressed it transiently in COS-7 cells. Expression level was about 5 times higher than with SV40 early promoter. Linear plasmids pMG10102 and pSV2-dhfr were then cotransfected into CHO-dhfr cells by calcium phosphorate coprecipitation and cells were cultured in selective medium. Twenty transformants expressing pro-UK were picked, the range of expression levels was 12.5-100IU/10(6) cells/day. When subjected to stepwise selection of methotrexate (MTX), the stable cell lines were obtained that secreted up to 400-500IU/10(6) cells/day. Western blot analysis showed that molecular weight of secreted recombinant pro-UK was the same as that of natural pro-UK, which is 52 kDa, and more than 60% of expression production was single chain urokinase (rscUK) without protease inhibitor in medium.

Animals↗
PubMed1993

[The changes in the levels of angiotensins and angiotensin converting enzyme and effects of captopril in patients with hypoxic pulmonary hypertension].

The levels of angiotensin I, II (ATI, II) and angiotensin converting enzyme (ACE) were measured in 28 patients with hypoxic pulmonary hypertension and 23 normal individuals. The effects of captopril were observed in 8 of 28 patients. The results showed that the average level of ATII in the patients was significantly higher than that in normal control (P < 0.05), but the average level of ACE in the patients was significantly lower than that in the controls (P < 0.05). In 8 patients, after the use of captopril, an ACE inhibitor, for two weeks, the levels of ATII, ACE and mean pulmonary arterial pressure (mPAP) were markedly decreased (P < 0.05). But the other 20 patients treated with antibiotics, antiasthmatics, diuretics and oxygen therapy for two weeks did not show any alterations in the levels of ATII, ACE and mPAP.

Aged↗