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Biomedical subjects

X Jiang

Publications and source records attributed to X Jiang.

At least 397 records · Page 22Linked to original sources
PubMed1995

[Morphological transformation of BHK-21 cells by nickel titanium shape memory alloy particles encapsulated by titanium oxide].

The special treatment process formed a compact titanium oxide thin film on the surface of medical nickel titanium shape memory alloy (NiTiSMA) particles (< or = 5 microns). The BHK-21 cells were cultivated in 10% infant calf serum containing NiTiSMA particles and NiTiSMA particles encapsulated by titanium oxide respectively, and morphological transformation clones were observed. The results showed that NiTiSMA particles induced obviously morphological transformation clones, and that NiTiSMA particles induced obviously morphorogical transformation of BHK-21 cells (the rate of morphological transformation clones was 13.46%), especially in TPA medium. The rate of morphological transformation in the group containing NiTiSMA particles was not more significantly different than that in the positive control group. The rate of morphological transformation in the group containing NiTiSMA particles encapsulated by titanium oxide was not more significantly different than that in the negative control group, but significantly different than that in the NiTiSMA particles group. Therefore, it is possible that NiTiSMA particles are directly carcinogenic and that NiTiSMA particles encapsulated by titanium oxide are not potentially carcinogenic.

Alloys↗
PubMed1995

[Distribution of fibronectin in experimental traumatic proliferative vitreoretinopathy].

A rat model of proliferative vitreoretinopathy (PVR) was induced by a penetrating injury at the posterior segment of an eyeball. Immunohistochemical methods (PAP) was used for observation of the distribution of fibronectin (Fn) in the model. The chief results of this study were as follows: 8 hours after the penetrating injury, a large amount of Fn was accumulated at the wound and the vitreous cavity. On the third and 7th day after trauma, fibroblasts proliferated at the wound where Fn was located and grew into the vitreous cavity. In 14-28 days after the injury, being closely related to the proliferative fibrous tissue, Fn was distributed among the fibroblasts and the newly synthesized collagen fibers. Macrophages are the main inflammatory cell of traumatic PVR and there was rich in Fn at the surfaces of the macrophages. The results indicate that Fn is the major component in the matrix of traumatic PVR and it possibly plays an important role in the development of PVR.

Animals↗
PubMed1995

[Experimental study on the arteriovenous reversal for revascularization of ischemic brain].

Twenty-eight New Zealand white rabbits were randomly divided into experimental group (n = 20) and control group (n = 8). In the experimental group, the bilateral common carotid arteries were ligated, the blodd flow of right common carotid artery was reversed into the right cephalic internal jugular vein distal to the facial common vein, and the arterial and venous blood were obtained from the cerebral circulation pre and postoperatively for blood gas analysis. While in the control group, only the bilateral common carotid arteries were ligated. Both experimental group and control group were further divided equally into 4 subgroups for histological study at the 48th hour and on the 14th day after operation, cerebral angiography and ink injection on the 14th day of postoperation, and long survival observation, respectively. The results showed that all the animals survived. In the experimental group, the blood gas analysis revealed no statistical difference (P > 0.05) between pre- and postoperative. the cerebral circulation was rich and patent, and the cerebral cells were normal. In the control group, however, the cerebral blood flow was inadequate and the cerebral cells necrosed extensively. It is concluded that the adequate revascularization of ischemic brain can be created by the arteriovenous reversal.

Animals↗
PubMed1994

Zuo et al. reply.

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Journal Article↗
PubMed1994

Phosphorylation, high ionic strength, and calmodulin reverse the binding of MARCKS to phospholipid vesicles.

The myristoylated alanine-rich protein kinase C substrate (MARCKS) is a major cellular substrate of protein kinase C (PKC), and PKC phosphorylation produces translocation of MARCKS from membrane to cytoplasm in many cells. Our working hypothesis is that binding of MARCKS to biological membranes requires both hydrophobic insertion of its myristoyl chain into the lipid bilayer and electrostatic interaction of its basic domain with acidic lipids. We tested this hypothesis by measuring the binding of murine MARCKS to large unilamellar phospholipid vesicles (LUVs). We estimated the partition coefficient of the myristoyl moiety of MARCKS (KH) by measuring the binding of MARCKS to electrically neutral LUVs (KH = 3 x 10(3) M-1). We examined the effect of electrostatic interactions by measuring the binding of MARCKS to LUVs containing 20% acidic lipid and obtained four results. First, incorporating 20% acidic lipid into the LUVs increased binding of MARCKS about 100-fold. Second, PKC phosphorylation, which added 3 negatively charged phosphate groups to the basic domain, reduced 20-fold the binding of MARCKS to these negatively charged vesicles. Third, increasing the KCl concentration from 0.1 to 0.5 M reduced the binding 15-fold. Fourth, Ca(2+)-calmodulin reduced the binding 20-fold. We present a simple theoretical model that explains these results, which are all consistent with the working hypothesis.

Animals↗
PubMed1994

Transformation of lupus-inducing drugs to cytotoxic products by activated neutrophils.

Drug-induced lupus is a serious side effect of certain medications, but the chemical features that confer this property and the underlying pathogenesis are puzzling. Prototypes of all six therapeutic classes of lupus-inducing drugs were highly cytotoxic only in the presence of activated neutrophils. Removal of extracellular hydrogen peroxide before, but not after, exposure of the drug to activated neutrophils prevented cytotoxicity. Neutrophil-dependent cytotoxicity required the enzymatic action of myeloperoxidase, resulting in the chemical transformation of the drug to a reactive product. The capacity of drugs to serve as myeloperoxidase substrates in vitro was associated with the ability to induce lupus in vivo.

Animals↗
PubMed1994

Developmental expression of the protein kinase C family in rat hippocampus.

Protein kinase C (PKC) is a heterogeneous family of ten or more isoforms which plays an important role in neuronal signal transduction. Isoforms from all subclasses are prominently expressed in the rat hippocampus, as demonstrated by immunoblot with isozyme-specific antisera: Ca(2+)-dependent (alpha, beta I, beta II and gamma), Ca(2+)-independent (delta, epsilon and a newly characterized PKC related to eta) and atypical (zeta). In addition, the zeta isoform is also found as the free, constitutively active catalytic domain, protein kinase M zeta (PKM zeta). Two distinct patterns of expression of PKC isozymes in rat hippocampus are found during development from E18 to P28. PKC zeta, PKM zeta and PKC delta are present at birth and their expression does not increase postnatally. In contrast, the other isoforms are expressed only at low levels at birth and then increase in the first 4 weeks postnatally. These two patterns of expression suggest distinct functions for PKC isozymes during development.

Aging↗
PubMed1994

Molecular characterization and expression of the capsid protein of a Norwalk-like virus recovered from a Desert Shield troop with gastroenteritis.

Norwalk virus (NV) infection was recently found to be associated with gastroenteritis in U.S. military troops stationed in Saudi Arabia during the 1990 Desert Shield Operation. We identified a Norwalk-like virus in the stools of two military personnel with gastroenteritis by ELISA and IEM. By RT-PCR and sequence analysis, the nucleotide sequence of part of the polymerase region of each of these two "Desert Shield" strains (DSV275 and DSV395) was found to be 73% identical to the corresponding region of NV. In addition, one of the strains (DSV395), which underwent sequence analysis of approximately 2900 consecutive bases, had a genomic organization characteristic of the Caliciviridae. Comparison of the DSV395 amino acid sequence of the capsid region with that of three other viruses in the Norwalk group (Norwalk, Southampton, and Toronto viruses) showed amino acid identity of 47-68%. Consensus sequence analysis of these capsid proteins identified two regions of conserved amino acids that flanked an area of variable amino acids. In addition, the proteins corresponding to the capsid regions of DSV395 and NV were expressed in an in vitro translation system. Immunoprecipitation studies using the expressed capsid proteins and paired DSV395 or NV infection sera indicated the presence of shared antigenic sites between the capsid proteins of DSV395 and NV. However, hyperimmune sera specific for the self-assembled recombinant NV capsid protein did not react with DSV stool antigen in an ELISA, suggesting that there may also be unique antigenic sites not shared between DSV395 and NV.

Amino Acid Sequence↗
PubMed1994

The Myb and Ahi-1 genes are physically very closely linked on mouse chromosome 10.

Ahi-1 has previously been identified as a common helper provirus integration site on mouse Chromosome (Chr) 10 in 16% of Abelson pre-B-cell lymphomas and shown to be closely linked to the Myb protooncogene. By using long-range restriction mapping, we have mapped the Myb and Ahi-1 regions within a 120-kbp DNA fragment. The Ahi-1 region is located approximately 35 kbp downstream of the Myb gene. A further confirmation of this finding was obtained by screening a mouse YAC library. The three positive clones obtained contained both the Myb and Ahi-1 gene sequences. To test whether provirus integration in the Ahi-1 region enhances the expression of Myb by a cis-acting mechanism, we have also examined Myb gene expression in A-MuLV-induced pre-B-lymphomas. Our data have revealed that there is no clear evidence for such activation in the tumors we have tested, indicating that provirus insertion in the Ahi-1 region is activating a novel gene, apparently involved in tumor formation.

Animals↗
PubMed1994

Clinical observations on the use of the Chinese herb Tripterygium wilfordii Hook for the treatment of nephrotic syndrome.

A preparation of extracts from the root of the Chinese medicinal herb Tripterygium wilfordii Hook was administered orally at a dose of 1 mg/kg body weight per day to 13 children with idiopathic nephrotic syndrome. Eight children, including 4 who were steroid resistant, went into remission which was maintained in 4 for up to 3 years after withdrawal of treatment. In 3 children the proteinuria lessened with the return of plasma protein concentration to normal, and in 1 child this improvement was maintained for 4 years after treatment ceased. No serious side-effects were noted, but a temporary anti-fertility activity has been noted in other studies of both men and women.

Administration, Oral↗
PubMed1994

Blood pressure changes and hormonal contraceptives.

The effects of low-estrogen and progestogen-only contraceptives on blood pressure changes were investigated on 238 women taking 35 micrograms EE OC, 267 using Norplant implants and 259 adopting IUD. The mean increases in diastolic pressure at 12, 24, 36 and 48 weeks among pill users were significantly (p < 0.05) higher than those among IUD users by 1.8, 2.1, 2.3 and 1.9 mm Hg, respectively; the increases in systolic pressure were higher but not significant (p > 0.05) by 1.3, 1.7, 1.5 and 1.3 mm Hg. Neither systolic nor diastolic blood pressure was affected by use of Norplant implants. Regression analysis, including interaction terms, showed that women's age, obesity and family history of hypertension were associated with an increase of blood pressure during follow-up and were independent of contraceptive use and vice versa. After adjustment of some potential confounding variables, pill users showed a 1.0 mm Hg rise in diastolic pressure, which is statistically significant but clinically unimportant.

Adult↗