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Biomedical subjects

D Liu

Publications and source records attributed to D Liu.

At least 649 records · Page 36Linked to original sources
PubMed1995

[Protective effects of tetrandrine on ischemic myocardia in anesthetized dogs].

The present study indicates that iv tetrandrine may transiently decrease blood pressure, while other hemodynamic parameters such as LVP, +/- dp/dtmax, LVEDP, HR and CO may not be significantly altered. During coronary occlusion three of five dogs developed ventricular fibrillation (VF) and died in the control group, i.e. incidences of VF and mortality were 60%. While tetrandrine (Tet) appeared to reduce the severity of ischemic injury. It may alleviate arrhythmia and prevent VF and death in four of the five dogs. Tet also attenuated Ca2+ accumulation in myocardial cell, reduced melondialdehyde (MDA) production in ischemic myocardial and decreased CPK release in comparison with the control. It appears that Tet may have significant protective effects against ischemia induced cardiac damage in anesthetized dogs.

Alkaloids↗
PubMed1995

An animal study on transmission of hepatitis B virus through mosquitoes.

Three gena of mosquitoes were fed with human blood infected with hepatitis B virus (HBV) artificially. When blood in the stomach was completely digested, mosquitoes were used to bite monkeys Tupaia Belangeri. A month after biting, venous blood samples were taken from the monkeys to detect serum HBsAg, HBeAg, Anti-HBs and Anti-HBc. Among 29 test monkeys, 9 were HBV infective serum markers positive. In 4 of 16 test monkey liver biopsies, acute inflammatory changes were found with Hematoxylin-Eosine staining. In the hepatic cells, HBsAg and HBcAg were detected by immunohistochemical double-labeling assays, and HBV-DNA was also positive by in situ hybridization in monkey liver sections. These results provided an evidence for the possibility of transmission of HBV through mosquitoes and suggest its epidemiological significance in mosquito infested areas.

Animals↗
PubMed1995

Effect of angiotensin converting enzyme inhibitors on tolerance of nitroglycerin.

The aim of this study was to assess whether the angiotensin-converting enzyme inhibitors captopril and enalaprilat could change the tolerance of nitroglycerin in isolated rat aortae. In aortic rings precontracted with potassium chloride, captopril (1 microM) but not enalaprilat (0.1 microM) incubation potentiated the responses to nitroglycerin. It is suggested that captopril can reduce the tolerance of nitroglycerin because it is a sulfhydryl group donor.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

[Evaluation of surgical treatment for patients with multiple aldosteronoma: analysis of 11 cases].

From 1957 to 1994, 332 patients underwent surgical treatment for aldosteronoma at Ruijin Hospital. Among them, 11 patients (3.9%) were diagnosed as having multiple aldosteronoma. We ususally used the same method to make the qualitative diagnosis for both single and multiple aldosteronoma. In our experience, however, it was difficult to distinguish the unilateral multiple aldosteronoma by rutine B-type ultrasonography, CT or gamma-scintigraphy before surgery. The correct diagnosis could be obtained only by carefully exploring during the adrenal operation and a satisfactory prognosis also can be acquired if multiple aldosteronoma could be removed completely.

Adenoma↗
PubMed1995

Effect of monoclonal antibodies on the entry and development of Plasmodium vivax sporozoite in cultured cells.

We have observed the effect of monoclonal antibodies against sporozoites (2F2,NV3,2E10) and blood stages (4B2,8E3) of P. vivax on entry and subsequent development of P. vivax sporozoites in HepG2--A16 cells in vitro. The results demonstrated that inhibitory effects of monoclonal antibodies on the attachment and entry were found to be related to the antibody concentration. At 25 micrograms/ml, the percentages of inhibition of sporozoite invasion were 100% (2F2), 76%(NVS3) and 10.5% (2E10). Even if the invasion was not totally inhibited, the presence of abnormal exoerythrocytic schizonts suggested that continued effect of antibodies after sporozoite penetration still existed. No significant effects of 4B2 (4.5%) and 8E3 (3.4%) were recorded as compared with normal mouse serum. These findings indicate that inhibition of sporozoite invasion assay may be useful for determining the protective effect of anti-sporozoite antibodies in vitro.

Animals↗
PubMed1995

[A clinical analysis of 93 cases with corticosteroid cataract].

According to the classical diagnostic criteria, the characteristics of 93 cases (182 eyes) of corticosteroid cataract (CSC) were investigated to analyze the relationship between its lens opacity and each of the following items: the duration, total amount of corticosteroid used, visual acuity and glaucoma. Posterior capsular lens opacity can be found in a sensitive patient after four months of administration of corticosteroid. Juvenile and male patients are vulnerable to the disease. Particularly, the variation of III-grade lens opacity is much closely related to the duration and total amount of corticosteroid used. 83.8% of patients were accompanied by glaucoma which may be the main cause of visual impairment of I and II grade lens opacity. The authors propose that CSC be divided into four grades according to the distribution and degree of the lens opacity. It should be alert that CSC might be accompanied by glaucoma.

Administration, Topical↗
PubMed1995

[Retrograde insertion of a spherical headed silicon tube through nasolacrimal duct].

PURPOSE: Chronic dacryocystitis or obstruction of nasolacrimal duct is one of the common and refractory eye diseases. The present operations have large destruction to lacrimal passage and unsatisfactory effects. The purpose of this research is to explore a simple and easy surgical method that makes small injuries and good curative effects. METHODS: Prob a self-made lumbar puncture needle (No. 7) through the lacrimal drainage system, inject fluid and put a thread into the inferior meatus. Guided by the thread, a special robe is retrogradely pulled through the nasolacrimal duct to dilate the meatus to about 3 mm. Then a silicon tube with a spherical head was inserted in the same may. RESULTS: 37 cases with chronic dacryocystitis or obstruction of nasolacrimal duct were treated by the method and followed up from 6 to 17 months. The result showed that the naso meatus was unobstructed postoperatively. The curative rate was 83.7%, which is better than that of other surgical methods. CONCLUSION: This operation is simple and painless for patients; has good curative effects and no severe complications: seldomly injures the normal lacrimal drainage system; can be done repeatedly or replaced by dacryocystorhinostomy if the procedure fails and will become the primarily elected method th treat the patients with chronic dacryocystitis and obstruction of the nasolacrimal duct.

Adult↗
PubMed1994

Assignments of 1H, 15N, and 13C resonances for the backbone and side chains of the N-terminal domain of DNA polymerase beta. Determination of the secondary structure and tertiary contacts.

DNA polymerase beta consists of an N-terminal single-stranded DNA binding domain and a C-terminal catalytic domain separable by mild proteolysis [Kumar et al. (1990) J. Biol. Chem. 265, 2124-2131]. The N-terminal domain participates in template and gapped DNA recognition and contributes significantly to catalysis. The secondary structure and tertiary contacts within the cloned N-terminal domain (residues 2-87) of mammalian DNA polymerase beta have been determined using multidimensional NMR. Assignments of backbone 1H, 15N, and 13C resonances and side chain 1H and 13C resonances have been obtained from double- and triple-resonance 3D NMR experiments. The 13C-edited TOCSY experiment has allowed nearly complete assignments of 1H and 13C resonances within side chains. The 13C-edited NOESY experiment has been used for determination of medium- and long-range NOEs and a determination of tertiary contacts. The N-terminal domain is found to consist of four helices, helix-1 (15-26), helix-2 (36-47), helix-3 (56-61), and helix-4 (69-78), which on the basis of long-range NOEs are tightly packed of form a hydrophobic core. The remainder of the domain consists of two turns (48-51 and 62-65), an omega-type loop (27-35), and extended structure. The aromatic side chains of Y36, Y39, Y49, and F76 display tertiary contacts indicative of at least partial hydrophobic packing. The S30 and H34 residues which cross-link to single-stranded DNA [Prasad et al. (1993) J. Biol. Chem. 268, 15906-15911] are contained within the K27-K35 loop.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Osmotin overexpression in potato delays development of disease symptoms.

Transgenic potato and tobacco plants carrying the osmotin gene under the control of the cauliflower mosaic virus 35S promoter constitutively overexpressed osmotin to a level of approximately 2% of total cellular protein. Leaves of transgenic potato plants exhibited delayed development of disease symptoms after inoculation with spore suspensions of Phytophthora infestans, which is the cause of late blight disease of potato. In contrast, transgenic tobacco plants did not display any change in the development of disease symptoms when challenged with either spore suspensions or fungal mycelia of Phytophthora parasitica var. nicotianae. Using in vitro assays, purified osmotin was found to be more effective against P. infestans. Some inhibition of P. parasitica also was observed in vitro even though no in vivo effect could be established.

Journal Article↗
PubMed1994

TGF-alpha can act as morphogen and/or mitogen in a colon-cancer cell line.

Transforming growth factor alpha (TGF-alpha) has multifunctional biological effects on a variety of mesenchymal and epithelial cells. It is a potent mitogen for a number of normal and transformed cell types, regulates extracellular matrix (ECM) production and promotes breast, kidney and lung morphogenesis. To clarify the role of ECM proteins in the morphogenetic and mitogenic effects of TGF-alpha, we have used a human colon carcinoma cell line (SW1222) which expresses EGF receptor. Here we show that TGF-alpha at 1 ng/ml increases the proliferation of SW1222 cells, but only when they are cultured on plastic rather than collagen-coated plates. Higher concentrations of TGF-alpha (10 ng/ml) did not increase cell proliferation but significantly enhanced the crypt-like glandular differentiation when cells were grown in 3-dimensional collagen gel (p = 0.027). These effects were accompanied by increased expression of alpha 2 beta 1 and alpha 3 beta 1 integrin molecules, which are receptors for extracellular matrix proteins, and by a statistically significant increase in binding of SW1222 cells to type-1 collagen. The effects of TGF-alpha both on binding to type-1 collagen and on morphological differentiation in 3-dimensional collagen gel were inhibited by monoclonal antibodies recognizing the alpha 2 beta 1 integrin. These data indicate that the morphogenetic or mitogenic activities of TGF-alpha are critically dependent on cellular interactions with extracellular matrix proteins and are primarily mediated by the alpha 2 beta 1 integrin receptor. Inappropriate expression of this growth factor, seen in tumours whose cell-matrix interactions are greatly impaired, could have deleterious effects on the maintenance of normal tissue architecture and growth control.

Antibodies, Monoclonal↗
PubMed1994

Loss of membranous E-cadherin expression in pancreatic cancer: correlation with lymph node metastasis, high grade, and advanced stage.

Epithelial cadherin (E-cadherin) is a Ca(2+)-dependent cell-cell adhesion molecule that connects cells via homotypic interactions. Its function is critical in the induction and maintenance of cell polarity and differentiation, and its loss of downregulation is associated with an invasive and poorly differentiated phenotype in colon and other tumors. We have used an avidin-biotin immunoperoxidase technique to localize E-cadherin in microwave-treated, paraffin-embedded sections from 36 patients with pancreatic adenocarcinomas. E-cadherin was expressed by normal ductal and acinar cells with typical membranous staining at the intercellular junctions. Loss of normal surface E-cadherin expression was found in 19/36 (53 per cent) tumours compared to the adjacent normal ductal cells. Abnormal E-cadherin expression was found more frequently in poorly differentiated (grade III) (6/7, 86 per cent) than in well-differentiated tumors (grade I) (4/14, 28 per cent) (P = 0.012). Membranous E-cadherin expression was also lost more frequently in primary tumours with lymph node (stage III) (14/23, 61 per cent) and distant metastasis (stage IV) (2/2, 100 per cent) compared with 3/11 (27 per cent) lymph node-negative tumours (stage I) (P = 0.043). In conclusions, our data indicate that loss of membranous E-cadherin expression is associated with high grade and advanced stage in pancreatic cancer.

Adenocarcinoma↗
PubMed1994

Microanalysis of cholesterol, phospholipid, and medium- and long-chain fatty acids in biologic materials.

We have developed a procedure for the microanalysis of the cholesterol and phospholipid concentrations and the fatty acid (including medium-chain fatty acids) composition of total lipid and phospholipid. One-milligram lipid samples were extracted from jejunal brush border membranes isolated from rats fed a diet containing 14% medium-chain triglycerides. The samples were analyzed by gas chromatography using an autosampler. We were able to identify 17 fatty acids in the total lipid and in the phospholipid fractions. The cholesterol and phospholipid contents of the membranes were 270 +/- 21 and 298 +/- 35 nmol.mg protein-1, respectively; thus the cholesterol/phospholipid ratio was 0.92 +/- 0.05, a value typically reported for the rat. Medium-chain fatty acids were not detected in the brush border membranes. Therefore, to demonstrate that medium-chain fatty acids were not lost during analysis, we analyzed the rat diet, and brush border membrane samples to which medium-chain triglycerides had been added. Recovery of medium-chain fatty acids from brush border membrane samples was 95.7 +/- 2.6%. The percentage of medium-chain fatty acids detected in the diet was not significantly different from the percentage when the diet was prepared. In summary, our procedure enabled a complete lipid analysis of very small biologic specimens.

Animals↗