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Biomedical subjects

J Dong

Publications and source records attributed to J Dong.

At least 235 records · Page 13Linked to original sources
PubMed1991

Development and characterization of polyclonal antibodies against chicken adipocytes.

1. Antisera against chicken adipocytes were developed in sheep. These crude antisera showed a high degree of reactivity to adipocyte plasma membranes but also cross-reacted to a lesser extent with other tissues. 2. Antisera cross-reactivity was removed by adsorption of the antisera with various chicken tissue plasma membranes. 3. Antisera reacted with differing affinity to adipocyte plasma membranes from several species of animals.

Adipose Tissue↗
PubMed1991

Islet cell and extrapancreatic expression of the LIM domain homeobox gene isl-1.

The phenotypically distinct cell types of the islets of Langerhans express a number of different hormone genes in a regulated and cell-specific manner. Analysis of the molecular factors important for the control of insulin gene transcription has led to the identification of a number of insulin gene-binding proteins. The cDNAs for several of these proteins have been isolated, including isl-1, a LIM domain homeobox protein reported to be preferentially expressed in islet cells. We now report that isl-1 mRNA transcripts are present not only in islet cells, but also in pheochromocytoma (PC-12) cell lines. Isl-1 mRNA transcripts were also detected in several different regions of rat brain as well as in rat kidney. Analysis of the patterns of gene expression in rat islet cell lines and human pancreatic endocrine tumors demonstrated a variable relationship between the hormonal phenotype of the tumor and expression of the isl-1 and insulin genes. Immunocytochemical studies demonstrated both cytoplasmic and nuclear staining for isl-1 in human pancreatic endocrine tumors, in normal pancreatic A, B, D, and PP cells, and in distal tubular cells of the kidney. Isl-1 immunoreactivity was also widely distributed in neurons in both the central and peripheral nervous system, pituitary, and several human pituitary tumors and pheochromocytomas. The results of these studies implicate a potential role for isl-1 outside the endocrine pancreas in the nervous system and kidney.

Animals↗
PubMed1990

Expression and characterization of an active human estrogen receptor as a ubiquitin fusion protein from Escherichia coli.

The gene coding for the human estrogen receptor protein was expressed as a ubiquitin fusion under the control of the lambda PL promoter in Escherichia coli. Analysis of extracts by Western blot showed that intact receptor protein was produced only when PL promoter was depressed by nalidixic acid at 30 degrees C. To ascertain the intactness of the expressed protein, estrogen receptor in bacterial extracts was titrated with either 17 beta-[3H]estradiol or 17 beta-[125I]iodoestradiol, and the mass was quantified by enzyme immunoassay. Cell extracts contained 484 fmol of estrogen receptor per mg of soluble protein by titration with a Kd of 3.2 x 10(-10) M. The simultaneous analysis by enzyme immunoassay resulted in 487 fmol/mg of extract protein indicating that most of the expressed protein bound ligand with wild type properties. Ligand competition analysis demonstrated that expressed receptor contained a binding domain preferentially recognizing estrogenic substances identical with that of wild-type estrogen receptor. The E. coli-expressed estrogen receptor also associated specifically with estrogen response DNA elements. Full length receptor protein was detected by ligand binding and immunorecognition using size exclusion chromatography. Hydrophobic interaction chromatography showed a major isoform which exhibited both ligand binding and immuno-recognition identical with the estrogen receptor from human breast tumor tissues. These data indicate that estrogen receptor expressed in E. coli retained characteristics of the native protein found in human tissues.

Blotting, Western↗
PubMed1990

[Effects of As2O3, MNNG and B(a)P on epithelia of human fetal tracheae and rat tracheae in organ culture].

The effects of As2O3, MNNG and B(a)P on epithelia of human fetal tracheae and rat tracheae in organ culture were studied. In human fetal trachea, a small dose of arsenic (1 mumol As) induced hyperplasia of the epithelium; 3-9 mumol As induced hyperplasia and cellular atypia in the epithelium, and hyperplasia and squamous metaplasia in the adenoepithelium. Similar effects were not observed in rat tracheae. MNNG and B(a)P induced hyperplasia, squamous metaplasia and dysplasia in human fetal tracheal and rat tracheal epithelia respectively, and MNNG also induced hyperplasia and squamous metaplasia in human fetal tracheal adenoepithelium. The data suggest that 1) arsenic may be carcinogenic to the human respiratory tract but not to the rat; and 2) human tissues in organ culture are very useful for detecting carcinogens and for studying carcinogenesis.

Animals↗
PubMed1989

[Cyclic AMP levels in the plasma and ischemic myocardium and free fatty-acid levels in the serum following coronary artery ligation in dogs: relation to ventricular fibrillation].

This study was designed to shed light on the biochemical causes of serious ventricular arrhythmias in the early stage of acute myocardial infarction (AMI). Fourteen mongrel dogs were divided into 2 groups. One group was subjected to coronary ligation by placing silk sutures around the LAD coronary artery about 1.5 cm from its origin. All the dogs of this group were found to have ventricular tachycardia and fibrillation, starting approximately 18 min. After ligation, associated with regional accumulation of myocardial cAMP in the ischaemic zone. The increase of cAMP started about 10-15 min. before the onset of the arrhythmia. In contrast, the control group had only sutures placed without ligation and was not found to have change in myocardial cAMP within 35 min and arrhythmias at the same time. Both plasma cAMP and serum FFA were studied, but no significant changes were found. It is concluded that myocardial cAMP may play an important role in the genesis of ventricular arrhythmias in the acute ischaemic heart and it may be one of the arrhythmogenic factors to evoke ventricular arrhythmias.

Animals↗
PubMed1989

[Cytolytic action of normal human natural killer cells on CNE-2 nasopharyngeal carcinoma cell in vitro].

Cytolytic actions of human natural killer cells, which were separated with nylon wool column from normal human peripheral blood, were investigated on human nasopharyngeal carcinoma cell line cells (CNE-2) and the dynamic processes of conjugation and cytolysis were studied. It was found that NK cells attacked living target cells and the course of cytolysis might be divided into 2 types according to their rapid or slow responses. In addition to the large granular lymphocytes the non-granular lymphocytes also participated in NK functions.

Humans↗
PubMed1986

Menstrual blood loss, haemoglobin and ferritin concentration of Beijing women wearing steel ring, VCu 200, and TCu 220c IUDs.

Menstrual blood loss (MBL), serum ferritin and whole blood cyanmethemoglobin were measured at pre- and 1, 3, 6, 12, 18 and 24th postinsertion cycles in 60 women wearing the Steel Ring, the Copper V (VCu 200) or the Copper T (TCu 220c). The MBL, incidence of menorrhagia and iron deficiency anemia were lower among users of the Steel Ring than among users of the Copper V and T. Anemia occurred later and the duration of menstruation was shorter with the Steel Ring than with the Copper T. There were no statistically significant differences between the Copper V and T.

Anemia↗
PubMed1986

The role of Phlebotomus alexandri Sinton, 1928 in the transmission of kala-azar.

Since 1968, kala-azar has been occurring sporadically in Meiyaogou, Turfan County, Xinjiang-Uygur Autonomous Region, where four species of sandflies are known to exist. The present study of sandflies collected in this area from May to August 1983 shows that Phlebotomus alexandri is the only anthropophilic and predominant species, accounting for 81.1% (7716/8843) of the sandfly population. After having been fed on cotton rats or hamsters infected with Leishmania donovani, 93.9% (230/245) of P. alexandri were infected, the promastigotes not only developing in the stomach but also invading the pharynx, buccal cavity and proboscis. Of the 643 female P. alexandri collected in the wild and in house, 13 (2.0%) were found to be naturally infected, with a distribution of promastigotes similar to that in the experimental infection. All the Chinese hamsters and golden hamsters that had been inoculated with 7 isolates of promastigotes from naturally infected sandflies developed visceral leishmaniasis. In addition, golden hamsters could be infected experimentally by the bite of P. alexandri which had an infection of promastigotes of L. donovani. This is the first demonstration of a species of Paraphlebotomus playing a role in the transmission of kala-azar in the Old World; studies for confirmation by biochemical identification of parasite isolates from naturally infected P. alexandri are now in progress.

Animals↗
PubMed1984

Immunoperoxidase evaluation of lymph nodes from acquired immune deficiency patients.

Immunoperoxidase evaluation of cryostat sections from acquired immune deficiency syndrome (AIDS) or prodromal nodes indicated that the majority (75%) had T8 dominance as contrasted to reactive hyperplasia nodes of unknown origin which had 80% T4 dominance. The cells in the AIDS nodes in the interfollicular and medullary sinuses areas marked intensely for Ia as opposed to sparse scattering in the comparative group. Finally, the follicles in the study group as opposed to the comparative group demonstrated hypervariability both in size and shape as outlined by a thin mantle zone of BA-1 positive cells. On the basis of the above three immunological criteria it is considered as highly likely that an AIDS node can be distinguished as such as opposed to the conventional characterization of 'reactive hyperplasia'.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Strategies for targeting complement inhibitors in ischaemia/reperfusion injury.

A transplanted organ suffers inherently from an ischaemic insult and subsequent reperfusion injury. The severity of such early events is thought to influence the success of the transplant procedure, not only in the immediate post-transplant period, but also to predispose the graft to both acute and chronic rejection. In this paper, we review the influence of the complement system upon ischaemia,reperfusion injury. The recognition of the involvement of complement has led to novel strategies to try to modulate ischaemia/reperfusion injury, some of which we have summarized. Finally, we note our own strategy to target complement inhibition in ischaemic tissues.

Animals↗
PubMedDate not supplied

The structure of electronic states in amorphous silicon.

We illustrate the structure and dynamics of electron states in amorphous Si. The nature of the states near the gap at zero temperature is discussed and especially the way the structure of the states changes for energies ranging from midgap into either band tail (Anderson transition). We then study the effect of lattice vibrations on the eigenstates, and find that electronic states near the optical gap can be strongly influenced by thermal modulation of the atomic positions. Finally, we show the structure of generalized Wannier functions for amorphous Si, which are of particular interest for efficient ab initio calculation of electronic properties and forces for first principles dynamic simulation.

Electrons↗