Search PubMed⌕ Search

Biomedical subjects

X Du

Publications and source records attributed to X Du.

At least 145 records · Page 8Linked to original sources
PubMed1996

Murine interleukin-11 (IL-11) is expressed at high levels in the hippocampus and expression is developmentally regulated in the testis.

IL-11, derived from a bone marrow stromal cell line, has pleiotropic effects on both hematopoietic cells and nonhematopoietic cells. However, no previous studies have systematically addressed expression of IL-11 in primary tissues in vivo and the relationship of IL-11 tissue specific gene expression and function of IL-11 is not clear. In the present study, we examined constitutive IL-11 expression in various murine adult tissues in vivo. IL-11 mRNA is expressed in a wide range of normal tissues (including hematopoietic organs) at levels only detected by RT-PCR. IL-11 protein was detected in brain and testis by Western blot analysis. The in vivo cellular distribution of IL-11 expression was examined by in situ hybridization. In brain, IL-11 message is distributed in granular layer dentate gyrus and pyramidal cell layers of hippocampus. IL-11 is also expressed in anterior horn cells and lateral column neuronal cells of the spinal cord. In testis, IL-11 mRNA is expressed in round spermatids at stage VI-IX seminiferous tubules. IL-11 expression in testis is restricted to developing spermatogonia and is developmentally regulated, since no expression is seen in mice genetically deficient in germ cells and in mice prior to sexual maturation. These expression data correlate with functional data demonstrating that IL-11 stimulates proliferation in vitro of a hippocampus neuronal progenitor cell line and administration of IL-11 in vivo accelerates recovery of spermatogenesis after cytotoxic therapy. These studies suggest that IL-11 may be an important regulator in neural and testicular function.

Animals↗
PubMed1996

Identification of baculovirus gene that promotes Autographa californica nuclear polyhedrosis virus replication in a nonpermissive insect cell line.

A gene that promotes Autographa californica M nuclear polyhedrosis virus (AcMNPV) replication in IPLB-Ld652Y cells, a cell line that is nonpermissive for AcMNPV, was identified in Lymantria dispar M nuclear polyhedrosis virus (LdMNPV). Cotransfection of AcMNPV DNA and a plasmid carrying the LdMNPV gene into IPLB-Ld652Y cells results in AcMNPV replication. The gene maps between 43.3 and 43.8 map units on the 162-kbp genome of LdMNPV. It comprises a 218-codon open reading frame and encodes a polypeptide with a predicted molecular mass of 25.7 kDa. The predicted polypeptide is glutamic acid and valine rich and negatively charged, with a pI of 4.61. No protein sequence motifs were identified, and no matches with known nucleotide or peptide sequences were found in the AcMNPV genome or database searches that suggest how this gene might function. A recombinant AcMNPV bearing the LdMNPV gene overcomes a block in protein synthesis observed in AcMNPV-infected IPLB-Ld652Y cells. Using Southern blotting techniques, we were unable to identify a homolog in Orgyia pseudotsugata M nuclear polyhedrosis virus, a baculovirus that is routinely propagated in IPLB-Ld652Y cells. This suggests that the LdMNPV host range is unique among the baculoviruses studied to date. We named this gene hrf-1 (for host range factor 1).

Amino Acid Sequence↗
PubMed1996

Interleukin-11 prevents apoptosis and accelerates recovery of small intestinal mucosa in mice treated with combined chemotherapy and radiation.

Previous studies have shown that acute injury to rodent small intestinal mucosa as a result of either chemotherapy or radiation is caused by a combination of high-frequency cell death caused by apoptosis, continued migration of epithelial cells from the intestinal crypts toward the villi, and absence of adequate compensatory mitotic activity in the crypt bases. Recently, we have shown that IL-11, a novel multifunctional bone marrow stromal-derived growth factor, could stimulate rapid repair of small intestinal villous structures in mice treated with combined radiation and chemotherapy by increasing the mitotic index of crypt cells. To further clarify the biological mechanism responsible for its protective action, we used a similar experimental model to evaluate whether IL-11 could reduce the high frequency of apoptosis observed after cytoablative treatment. In the present study, 78 C3H/HeJ mice received 5-fluorouracil at 150 mg/kg body weight intraperitoneal injection 3 days before 7.0-Gy total body irradiation. The animals received IL-11 250 microg/kg body weight/day divided into two equal doses or vehicle control by subcutaneous injections beginning on the same day of irradiation within 1 hour of the end of the dose. The mice killed on Days 1, 2, and 5 after cytoablative treatment were autopsied, the small intestine was processed for histologic examination, and the mitotic index and other parameters were measured, including the expression of the proliferating cell nuclear antigen and of the p53 protein. Apoptosis was detected by a nonisotopic in situ DNA end-labeling technique applied to the same histologic sections. The cytoablative treatment caused marked degenerative changes in the small intestinal mucosa, including shortening of the villi and damage to the crypt cells. The degenerative changes, which included nuclear fragmentation with formation of apoptotic bodies, increased expression of proliferating cell nuclear antigen, and strong expression of p53 was seen in mice killed on Days 1 and 2 after cytotoxic treatment. IL-11 administration resulted in a partial suppression of apoptosis, as shown by a reduced number of crypt cells stained with in situ DNA end-labeling for fragmented DNA. In addition, IL-11 treatment was associated with an increase in the frequency of mitosis and proliferating cell nuclear antigen expression in crypt cells as compared with the vehicle treated mice. Morphometric analysis of intestinal villi and crypt depth showed increased villus length and decreased crypt to villus ratio after IL-11 treatment. These results indicate that IL-11 can exert a potent effect on the recovery of the small intestinal mucosa of mice by its combined effects on proliferation and apoptosis of crypt cells. IL-11 may thus have potential clinical applications in limiting the intestinal toxicity that is associated with cytotoxic therapies.

Animals↗
PubMed1996

Construction of a stable expression vector carrying sop genes [ZJ1].

Mini-F, the fifth fragment of F plasmid from EcoRI digestion, is known to carry an efficient partitioning function. Two pBR322 plasmid derivatives, pDMC32 and pDMC311, have been constructed from this fragment. The plasmid pDMC32 carries all the relative genes for plasmid stability, ccd, repD, and sop genes (sopA, sopB, and sopC), along with oriS and oriV, while pDMC311 carries only sop genes (sopA, sopB, and sopC). The plasmid maintenance proportions for pDMC32 and pDMC311 in E. coli were 93% and 100%, respectively, after 100 generations continuous cultivation of cells harboring the derivatives, MI32 (pDMC32) and MI311 (pDMC311), in a phosphate-limited basal medium. As a control, the maintenance proportion of plasmid pBR322 dropped down to a low of 10% at generation 55 of continuous cultivation of E. coli MIR322 (pBR322) in the same medium. In order to make a stable expression vector that carries only sop genes, plasmid pDMC40 was constructed by adding a trp promoter from pDR720 to pBR322. The stable expression vector pDMC48 was then derived from pDMC40 by inserting sop genes into it from pDMC311. The maintenance proportion of plasmid pDMC48 in E. coli was still 100% after 100 generations of continuous cultivation of cells harboring the plasmid in phosphate-limited basal medium.

Ampicillin↗
PubMed1996

[The prevention and treatment of complications after esophagogastrostomy by intraluminal elastic circular ligation].

To summarize our experience on the handling of postoperative complications of esophagogastrostomy by elastic circular ligation (IECL), 176 patients with esophageal or cadiac carcinoma underwent esophagogastrostomy by IECL with absorbable supporting tubes were reviewed. There were 7 cases of postoperative complications with an incidence of 3.97%. Of which, anastomotic leakage in 3 patients, recurrent laryngeal nerve paralysis in one and chylothorax in one were cured by conservative measures; one patient with hiatus hernia was treated by reoperation, and another patient died of right tension pneumothorax. After the causes of complications being analysed, improved operative procedures are recommended. (1) The esophagus must be dissociated up to the apex of pleural cavity when anastomosis is performed above the aortic arch, so as to have the lower end of the supporting tube at least 0.5 cm higher than the arch. (2) The supporting tube must be wrapped with the gastric wall and avoid suturing through the esophageal mucosa layer. (3) When the anastomosis is performed below the aortic arch, reconstruction of the hiatus should be done with the esophagus moved forward to prevent the thoracic aorta from eroded by the supporting tube. (4) If the residual gastric volume is less than one-third of normal, the above-mentioned operation procedures can not be employed.

Adult↗
PubMed1996

[A study of the thermosensitivity determination for the normal value of the twelve well-point (or jing-point)].

Under certain temperature and humidity, the thermosensitivity values of the twelve Well-point, on 209 healthy young people, selected at random/and aged from 20 to 24, were measured in the morning and in the afternoon respectively. The statistical results show that there is no significance (P > 0.05), when the value of one Well-point on upper limbs of the male is compared with that of the female, except very few well-point. The value of one Well-point on both the left side and the right side measured at the time are almost the same. The value of one Well-point on the lower limbs of the male is higher than that of the female, and the difference is significant (P < 0.05). This study indicates that the normal values of every Well-point exist in human beings, which will assist clinical diagnosis.

Acupuncture Points↗
PubMed1996

[Electro-acupuncture effects on experimental spinal cord injury of the cat as evaluated by acid phosphatase detection].

The spinal cords of adult cats were injured at about L1 level by using Allen's method and the animals were divided randomly into 2 groups: a) electro-acupuncture treatment group and b) control group. The acid phosphatase (ACP) was detected at 3 and 7 days after spinal cord injury. The more ACP positive labelings were found in the treatment group than in the control group at both 3 (P < 0.05) and 7 days (P < 0.01) after injury. The results suggested that electro-acupuncture could increase the concentration of ACP of the injured spinal cord and the increased ACP concentration could make worse to the injured spinal cord at early time and improve regeneration during recovery period.

Acid Phosphatase↗
PubMed1996

[Extra-capsular cataract extraction and intraocular lens implantation in cases with cataract and a small pupil with synechiae].

OBJECTIVE: To introduce a new surgical technique for cataract with a small synechia pupil and evaluate its effects. METHODS: 43 eyes of 40 patients were operated on and followed up for 3-30 months. Surgical procedures included iridectomy, separating the posterior synechiae, straight cutting of upper iris and making 3 little cuts at inferior pupillary margin, extracapsular cataract extraction, intraocular lens implantation, and at last suturing the iris cuts to form a round pupil. RESULTS: Postoperatively, all 43 eyes had 3-4 mm basically round pupil and 42 eyes (97.7%) had improved vision. Of the 32 eyes followed up for more than three months, 22 eyes (68.8%) obtained visual acuities 0.5 or better, 10 eyes (31.2%) had visual acuities worse than 0.4 which were attributed to posterior segment abnormalities. Intraoperatively, no posterior capsular rupture was seen, and postoperatively, no severe complications were found. CONCLUSION: The results suggest that patients with cataract and a small synechia pupil obtain improved vision and round pupil without unacceptable risk by means of the surgical technique mentioned in this paper.

Adolescent↗
PubMed1995

Calpain cleavage of the cytoplasmic domain of the integrin beta 3 subunit.

The cytoplasmic domains of integrin beta subunits are involved in bidirectional transmembrane signaling. We report that the cytoplasmic domain of the integrin beta 3 subunit undergoes limited proteolysis by calpain, an intracellular calcium-dependent protease. Calpain cleavage occurs during platelet aggregation induced by agonists such as thrombin. Five cleavage sites have been identified. Four of these sites (C-terminal to Thr741, Tyr747, Phe754, and Tyr759) are utilized in intact platelets and flank two NXXY motifs (Asn744-Pro-Leu-Tyr747 and Asn756-Ile-Thr-Tyr759). The fifth site (Ala735) is accessible to calpain after EDTA treatment of the alpha IIb beta 3 heterodimer. The NXXY motif is critical to the bidirectional signaling functions of beta 3 integrins and their association with the cytoskeleton. Thus, calpain cleavage of the beta 3 cytoplasmic domain may provide a means to regulate integrin signaling functions.

Amino Acid Sequence↗
PubMed1995

Brain-derived neurotrophic factor works coordinately with partner molecules to initiate tyrosine hydroxylase expression in striatal neurons.

Previous studies demonstrated that the cooperative interaction of acidic fibroblast growth factor (aFGF) and a partner molecule could induce the novel expression of the catecholamine (CA) biosynthetic enzyme, tyrosine hydroxylase (TH) in striatal neurons [Du and Iacovitti, J. Neurosci., in press; Du et al., J. Neurosci., 14 (1994) 7688-7694; Iacovitti et al., submitted]. The present study demonstrates that in addition to aFGF, brain-derived neurotrophic factor (BDNF) is also capable of moderate levels of TH induction (30% TH+ striatal neurons) when administered at high concentrations (100 ng/ml). As with aFGF, BDNF's activity depended on its coupling to an appropriate partner molecule; the most potent of which were 10 microM dopamine (DA) and 50 microM mazindol. BDNF + DA-induced TH expression was first evident after at 12 h; peaked by 18 h and declined by 4 days in culture. Cyclohexamide eliminated nearly all and alpha-amanitin reduced by half the TH induction elicited by DA and BDNF; indicating that both de novo transcription and translation were required for increased expression. In contrast with aFGF and BDNF, other putative dopamine differentiation factors, such as glial-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF), were able to elicit barely detectable (10%) levels of TH induction, regardless of the partner molecule used. These studies suggest that aFGF and/or BDNF may work coordinately with partner molecules to initiate TH expression; while a number of factors including, CNTF and GDNF, may be involved in its subsequent modulation.

Animals↗
PubMed1995

Platelet adhesion receptors.

The response to vascular injury involves attachment and aggregation of platelets, coupled with initiation of the coagulation cascade. These inter-related processes ensure that the vessel injury is rapidly blocked with an aggregated clump of platelets that is then stabilized by a crosslinked fibrin matrix. Initial adherence relies on the ability of the platelet adhesion receptors to bind subendothelial matrix molecules. Platelet activation then results in the expression of high affinity integrin receptors on the cell surface that bind soluble ligands, allowing platelets to aggregate and form a haemostatic plug.

Blood Platelets↗
PubMed1995

Mouse model of X-linked chronic granulomatous disease, an inherited defect in phagocyte superoxide production.

Chronic granulomatous disease (CGD) is a recessive disorder characterized by a defective phagocyte respiratory burst oxidase, life-threatening pyogenic infections and inflammatory granulomas. Gene targeting was used to generate mice with a null allele of the gene involved in X-linked CGD, which encodes the 91 kD subunit of the oxidase cytochrome b. Affected hemizygous male mice lacked phagocyte superoxide production, manifested an increased susceptibility to infection with Staphylococcus aureus and Aspergillus fumigatus and had an altered inflammatory response in thioglycollate peritonitis. This animal model should aid in developing new treatments for CGD and in evaluating the role of phagocyte-derived oxidants in inflammation.

Alleles↗
PubMed1995

Differences in colorectal cancer between China and Japan: a clinical and histological study of two groups of cases.

It is well known that most tumours are attributed to life style, especially the tumours of the digestive system. Clinical and histopathological investigation of tumours in different human groups and societies, and analysis of the variations will provide evidence for this, and is one of the approaches to study carcinogens. Clinical data obtained from 391 patients with colorectal cancer at the Sakai Municipal Hospital, Japan, and Shanghai Jinshan Hospital and Cancer Hospital, China, from 1987 to 1992, included the sex, age and tumour subsite. Sections of histological specimens were also retrieved. The results were compared between two countries. The average age of patients with colorectal cancer in Shanghai was 8.5 years less than in the Sakai group. The age peak of the former was 51-60, and in the latter, 61-70 years. The most frequent site of the cancer in the Shanghai group was the rectum, contrasting with the higher percentage of sigmoid colon cancer in Sakai group. There was also a significant difference in histological subtype of the cancer between the two groups. Mucinous adenocarcinoma was notably more common in the Shanghai group than in the Sakai group, and the high frequency was mainly in the colon. All of the variations were suggested to be attributable to differing socioeconomic circumstances and lifestyle, especially the dietary habits of the countries.

Adult↗
PubMed1995

Update on development of interleukin-11.

This paper reviews the recent studies of interleukin-11 gene expression and regulation, receptor and signal transduction, pharmacologic effects, and preclinical and clinical studies. Interleukin-11 is expressed in cells of mesenchymal origin and gene expression can be modulated by several inflammatory cytokines and agonists. The signaling pathways involved in cytokine induction of interleukin-11 gene expression vary between cell types. In vitro and in vivo studies reveal that interleukin-11 displays a wide spectrum of bioactivities including responses in hematopoietic and nonhematopoietic cells. Preclinical studies in animal models suggest that interleukin-11 may be useful in acceleration of the recoveries of both hematopoietic cells and gastrointestinal mucosal cells after cytoablative therapies. Several clinical studies have demonstrated interleukin-11 to be well tolerated and suggest interleukin-11 is a promising cytokine to prevent both neutropenia and thrombocytopenia in patients with cancer who are receiving chemotherapy.

Animals↗
PubMed1995

Synergy between growth factors and transmitters required for catecholamine differentiation in brain neurons.

The phenotypically plastic neurons of the embryonic mouse striatum were used to explore mechanisms of catecholamine differentiation in culture. De novo transcription and translation of the CA biosynthetic enzyme, tyrosine hydroxylase (TH), was induced in striatal neurons exposed, simultaneously or sequentially, to the growth factor, acidic fibroblast growth factor (aFGF) and a catecholamine. Although dopamine was the most potent aFGF partner (ED50 = 4 microM), a number of substances, including dopamine (D1) receptor agonists, beta-adrenoceptor agonists, and dopamine uptake inhibitors also trigger TH induction when accompanied by aFGF. However, since none of the receptor antagonists nor transport blockers tested could inhibit dopamine's action, the mechanism remains obscure. Structure-activity analysis suggests that effective aFGF partners all contain an amine group separated from a catechol nucleus by two carbons. Thus, TH expression can be novelly induced by the synergistic interaction of aFGF, and to a lesser extent basic FGF, and a variety of CA-containing partner molecules. We speculate that a similar association between growth factor and transmitter may be required in development for the differentiation of a CA phenotype in brain neurons.

Animals↗
PubMed1995

[An analysis of pathologic features and prognostic factors of 10 cases with pseudomyxoma peritonei].

OBJECTIVE: To investigate the histogenesis and the pathological features of pseudomyxoma peritonei and to analysis its prognostic factors. METHODS: Ten cases with pseudomyxoma peritonei were clinicopathologically studies, with follown-up at least 24 monthes. All histopathological sections and clinical data were reviewed. RESULTS: Seven out of 10 patients had the ovarian mucinous tumors which were bilateral in 5 cases (71.4%). Histopathologically, 4 of 7 cases with ovarian tumor were characterized by the presence of the multifocal bleeding, fragmental necrosis, and occasionally, the striated border on the glandular lumens. The mucinous epithelial cells and mucin invased into the peritonei, destroyed normal structure, and formed the desmoplasia. Four patients died of pseudomyxoma peritonei, all with extensive lesions, invasions in the peritonei, and a short recurrent time (mean, 12.0 monthes) after presentation. CONCLUSIONS: The histogenesis of pseudomyxoma peritonei is heterogenous, the presence of possible metastases including from the appendix, the colon and other organs. The most important factors of the prognosis should include the extent of initial lesions, the presence of invasion in the peritonei and a rapid recurrence.

Adult↗
PubMed1995

Biomedical material for sutureless esophagogastrostomy. Analysis of 31 cases.

The results of 31 cases of sutureless esophagogastrostomy by intraluminal elastic circular ligation (IECL) with the biodegradable supporting tube were reported. The fate of the supporting tube could be tracked satisfactorily by X-ray. The tube-dislodge time was 15.03 +/- 2.23 days and unaffected by the size of supporting tube or the site of anastomosis. The supporting tube could be safely absorbed or partially discharged through the alimentary tract. IECL, with the merits of saving time, anastomosing tightly and leaving no suture materials in the anastomotic site, can be expected to further reduce the incidence of anastomotic leakage and provide references for other gastrointestinal anastomosis.

Adult↗