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J Wu

Publications and source records attributed to J Wu.

At least 1,405 records · Page 78Linked to original sources
PubMed1992

Influence of long-chain acylcarnitines on voltage-dependent calcium current in adult ventricular myocytes.

Long-chain acylcarnitines (LCAC) increase 3.5-fold within 2 min in ischemic myocardium in vivo, and previous studies have suggested, through indirect evidence, that LCAC can stimulate the voltage-dependent L-type Ca2+ current [ICa(L)] in both cardiac and smooth muscle cells. In the present study, whole cell voltage-clamp procedures were performed in isolated adult guinea pig ventricular myocytes to assess the direct effect of LCAC on ICa(L). The intracellular solution contained (in mM) 80 CsCl, 40 K-aspartic acid, and 5 ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). Maximal current density of ICa(L) at 0 mV was 10.1 +/- 0.5 pA/pF (n = 22) at extracellular Ca2+ concentration ([Ca2+]o) = 2.7 mM. LCAC induced a concentration (1-25 microM, n = 23)- and time-dependent, reversible decrease in ICa(L). When delivered extracellularly for 10 min, LCAC (5 microM) inhibited the maximal current of ICa(L) by 48.1 +/- 1.3% (n = 9, P less than 0.01) and shifted the half-maximal voltage of steady-state activation and inactivation from -13.1 +/- 0.5 to -6.8 +/- 0.4 mV (n = 4; P less than 0.05) and from -21.8 +/- 0.2 to -16.5 +/- 0.6 mV (n = 4; P less than 0.01), respectively. Intracellular delivery of LCAC (5 microM) also suppressed ICa(L) to a similar degree (47.5 +/- 1.5%, n = 4; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Histopathologic correlates of acute laryngeal allograft rejection in a rat model.

This study used both clinical and histopathologic criteria to define the sequence and time parameters of rejection in histoincompatible vascularized rat laryngeal allografts. Clinical onset of rejection was characterized at 1 week by graft edema. Pathologic examination at this time revealed arterial wall thickening and a diffuse lymphocytic and macrophage mucosal infiltrate. At 14 days, the graft was encased in an inflammatory exudate with no visible cartilaginous structure. This correlated microscopically with a lymphocytic infiltrate of the lamina propria, loss of minor salivary glands, and squamous metaplasia of the surface respiratory epithelium. Arterial thrombosis was always correlated with tissue necrosis, but venous occlusion, occurring more than 2 days after transplantation, was not an independent determinant of graft viability. Definition of the time sequence and histopathology of rejection will allow future determination of the efficacy of various immunosuppressive regimens.

Acute Disease↗
PubMed1992

Rat model for a vascularized laryngeal allograft.

A new rat model was developed to reexamine the potential for laryngeal transplantation. The final anatomic derivation evolved from two earlier developmental phases. The first model had only a single arterial anastomosis; the second had an end-to-end arterial anastomosis with an end-to-end arteriovenous shunt. The final product employed an end-to-side arterial shunt and an end-to-side arteriovenous shunt for revascularization. The allografts were sited in tandem with the intact recipient larynges and were not innervated. A total of 16 animals were studied in phase 3; 2 died and the remaining 14 had a 64% arterial patency at intervals of 1 to 14 days. Our purpose is to detail the relevant technical considerations of this new model and compare it with historical controls.

Anastomosis, Surgical↗
PubMed1992

Differential binding of (+) and (-) gossypol to plasma protein and their entry into rat testis.

Concentrations of (+) and (-) gossypol were measured by high performance liquid chromatography after they were incubated with plasma proteins in vitro. The concentration of (-) gossypol decreased more than the concentration of (+) gossypol. A similar decrease in free gossypol concentrations in the blood plasma of rats was observed after intravenous infusion of gossypol enantiomers. The concentration of (-) gossypol was also found to be lower than the concentration of (+) gossypol at the blood-testis barrier. The biological effect of (-) gossypol probably results from its stereospecific binding to extra- and intracellular proteins in vivo and inhibition of the biological activity of some proteins.

Animals↗
PubMed1992

Surgical influence on murine immunity and tumor growth: relationship of body temperature and hormones with splenocytes.

Adrenalectomy predisposed the C3HeB/FeJ Mouse to tumor from a low dose of tumor cells, derived from a C3H spontaneous mammary adenocarcinoma. Sham surgery had a similar effect. In contrast, ovariectomized females, intact females, and male mice did not allow the low dose of cells to develop into a tumor. In order to better understand the role of hormones on the immune system controlling tumor growth, normal C3HeB/FeJ mice were studied for the effect of corticosterone or estradiol on splenic lymphocyte surface antigen expression. Adrenalectomy and ovariectomy caused a decrease in the percentage of all T cell subclasses and an increase in absolute numbers of immunoglobulin-bearing cells. Reconstitution of ovariectomized mice with estradiol did not significantly alter lymphocyte cell surface antigen expression. In contrast, injection of corticosterone into adrenalectomized mice brought these values to normal. Further study on normal mice placed on a 12:12-hr light:dark schedule showed that the hours after lights on (HALO) had a significant effect (analysis of variance) on body temperature, percentage of splenic B cells, T pan, T helper and T suppressor cells, and absolute numbers of T pan cells. Brain dehydroepiandrosterone sulfate correlated positively with T pan lymphocytes, but showed no significant effect on HALO. In contrast, body temperature showed a strong circadian rhythm (P less than 0.001). In addition, the presentation of estrus was circadian rhythmic (P = 0.003) with 58% of mice in estrus at 16 HALO and only 8% at 4 HALO. Multiple regression analysis revealed body temperature was strongly associated with absolute numbers of splenic T lymphocytes and their subsets, as well as percentage of B lymphocytes, Thy 1.2-, and Lyt-2-bearing cells. Similarly, HALO and estrous cycle stage were associated with percentage of T helper cells. The data showed that body temperature and hormones were associated with the cell surface antigens on lymphocytes and suggest that they affect lymphocyte function.

Adenocarcinoma↗
PubMed1992

[Simple spike response of cerebellar Purkinje cells to stimulation of C-fiber in saphenous nerve].

Simple spike of cerebellar Purkinje cells (PC-SS) was recorded with microelectrode. In the NCCVF (normalized cross-covariance function) histogram, spontaneous PC-SS does not show obvious peak. When the saphenous nerve is stimulated at lower intensities, which elicits the A-fiber input only, the discharge response (A-CED) consists of an early component with a latency of 16.7 +/- 0.9 ms and a late component with a latency of 270.8 +/- 12.8 ms. After A-fibers are blocked selectively by polarizing current, the stimulation at a suprathreshold strength for C-fiber evokes a characteristic response (C-CED) with a latency of 142.4 +/- 4.3 ms. However, the C-CED can not be evoked by the inputs of A- and C-fiber simultaneously. In NPSDF histogram, the spontaneous activities of PC-SS can be divided into two groups, the high and the low peak group. The high peak group (n = 15) has a peak energy value of 15.7 +/- 4.7 x 10(-3) and peak frequency of 4.07 +/- 1.69 Hz. A-fiber input causes an increase of the peak value, while C-fiber input causes a decrease. The low peak group (n = 16) has a peak energy value 8.4 +/- 1.4 x 10(-3) and peak frequency of 3.67 +/- 2.90 Hz. Both A-fiber and C-fiber inputs cause an increase of the peak value, but the effect of A-fiber input was more prominent. The results show that the pure C-fiber input can reach the cerebellar PC and elicit characteristic simple spike response.

Animals↗
PubMed1992

[The role of p53 gene in the switch of U937 leukemic cells from growth into differentiation].

The expression of p53 gene has been found to be regulated during the induction of differentiation of U937 leukemic cells into mature macrophages by recombinant human granulocyte- macrophage colony stimulating factors (rhGM-CSF) We showed here that the increased expression of p53 seemed to be necessary for the differentiation of U937 cells induced by rh-GM-CSF. The inhibition of p53 expression by a p53 antisense oligodeoxynucleotide lead to the significant decrease of formation of mature macrophages from U 937 cells in the presence of rhGM-CSF. By contrast, the p53 sense oligodeoxynucleotide had no any effect. Furthermore, we have analysed the growth of U937 cells in the presence or absence of rhGM-CSF. The results showed that rhGM-CSF dramatically inhibited the growth of U 937 cells in the cultures. At the same time, the antisense inhibition experiment demonstrated that the inhibition of p53 expression partially diminished the growth-inhibitory effect of rhGM-CSF on U 937 cells. These results suggested that the p53 was required for the initiation of rhGM-CSF-induced differentiation of U 937 cells on one hand, and the inhibition of cell growth on the other hand. Thus we deduce that the increased expression of p53 induced by rhGM-CSF may be a coupling event of switch of U 937 cells from growth into differentiation.

Cell Differentiation↗
PubMed1992

Molecular genetic analysis of two distinct receptors for mammalian bombesin-like peptides.

The mammalian bombesin-like peptides are known to be growth factors for certain cells with high-affinity bombesin receptors and have been implicated as autocrine growth factors influencing the pathogenesis and progression of a subset of human small-cell lung carcinomas. Thus, antagonists that interfere with bombesin receptor-ligand interaction might prove to be of value in treatment of gastrin-releasing peptide (GRP)-responsive tumors. A precise definition of the structure and properties of the bombesin receptors found on human lung cancer cells would provide important information for the design and rational application of such antagonists. Recently, we isolated cDNA clones encoding two distinct receptors for the mammalian bombesin-like peptides, GRP, and neuromedian B (NMB). The two receptors show 56% amino acid identity, encode seven putative transmembrane domains, and are members of the G-protein-coupled receptor superfamily. Ligand-binding studies show that while both receptors can be activated by either GRP or NMB, one receptor has a higher affinity for GRP than for NMB (GRP-R), while the other has a higher affinity for NMB than for GRP (NMB-R). A different spectrum of antagonists is needed to block responses from the two different receptors. These studies indicate that it will be critical in future studies to define which bombesin receptor subtypes are present on a given tumor to optimize the potential therapeutic benefit of antagonists in blocking growth.

Amino Acid Sequence↗
PubMed1992

[Preliminary use of recombinant glycoprotein 52kd as an antigen in the diagnosis of human cytomegalovirus infection].

Interest in the human cytomegalovirus (HCMV) mainly derives from its associations with congenital malformations, mental retardation, and severe or fatal infections in immunosuppressed individuals such as transplant patients, tumor and AIDS patients. It is evidenced that there has been a need for a rapid and sensitive methods to detect an ongoing acute infection. The recent studies showed that high titers of antibody to the glycoprotein 52kd are present in sera of patients undergoing acute HCMV infection. However, purification of individual glycoprotein from HCMV-infected cells is a daunting prospect. HCMV glycoprotein 52 kd expressed via recombinant DNA techniques are a promising approach to solve this problem. In order to evaluate the diagnostic value of the recombinant glycoprotein 52 kd antigenic code region for HCMV infection, we have used the polymerase chain reaction (PCR) and recombinant DNA techniques to construct successfully the high-level expression plasmid pHCMV containing the HCMV GP-52 kd antigenic code region, with the predicted protein at levels up to 20% in total bacterial protein. The expressed protein was purified from SDS-PAGE, used as an antigen in Western-blot, and reacted with 12 cases of the positive sera, 4 cases of the negative sera, following by reaction with HRP-labelled horse IgG antibody against human. The results indicated that the approach we are using to detect antibody to HCMV acute infection are as sensitive as general serological methods such as ELISA, with the advantages of easy preparation of antigen with high quantity, and clinical practicability.

Antibodies, Viral↗
PubMed1992

[Antisteatotic effects of four kinds of dietary fibers in rats fed on high cholesterol diet: a preliminary morphometric analysis].

The hypolipidaemic and antisteatotic effects of the Konnyaku Powder (KP) have been reported before. In order to evaluate further the antisteatotic role played by KP, the effects of KP on the levels of liver lipid and on the hepatic histopathology and morphometry in comparison with those of pectin, algin and agar were studied. Sixty Wistar strain rats were divided into 6 groups: a normal diet group, a high cholesterol diet group (HC), and 4 test groups, in which the animals were fed on a diet similar to that of the high cholesterol diet group with addition of KP, pectin, algin or agar at a dosage of 5%, respectively. All the animals were killed at the end of the diet treatment for 9 weeks. The results showed that relative liver weights were lower in four experimental groups than in the HC group. The levels of total and free cholesterol, and triglyceride in the liver were lower in KP group than in HC group and in the other three experimental groups. Hepatic histopathology and morphometric examination indicated that antisteatotic effects of KP appeared to be much more significant than those of the other fibers.

Agar↗
PubMed1992

[Management of liver trauma in adults: the results of selective nonoperative management and operative treatment].

The liver trauma is still one of the major injury in thoracoabdominal trauma, with increasing numbers and incidence in Taiwan. There is a trend toward a more conservative approach in the treatment of liver trauma. Nonoperative management for the stable patients with blunt liver trauma has been advocated in literature recently. In Veterans General Hospital-Taipei, forty-five patients with liver trauma have been admitted to Emergency Department after accident in past four years. Eighty-three percent of the trauma mechanism was blunt injury, and seventeen percent penetrating. There were ten patients selected as nonoperative management, and eight of them succeeded without operation. Retrospective analyzing various factors including age, trauma score, revised trauma score, injury severity score, amount of hemoperitoneum, blood loss and transfusion, morbidity and hospitalization, there are no statistic significances between nonoperative and operative groups, except that nonoperative group are less amount of blood transfusion. We suggest that the decision to treat the patient without laparotomy is not based on the degree of hemoperitoneum or the grade of liver injury, but rather on the stability of the patient. And further evaluation is needed.

Adolescent↗
PubMed1992

Selective inhibition of normal murine myelopoiesis "in vitro" by a Hox 2.3 antisense oligodeoxynucleotide.

Multiple homeobox genes are expressed in haematopoietic cell lineages and their expression is cell-type specific. Thus we hypothesized that certain homeobox genes may play an important role in the process of haematopoiesis. To prove that issue, normal murine bone marrow cells were stimulated with appropriate Colony Stimulating Factors in the presence of mouse homeobox gene (Hox 2.3) sense or antisense oligodeoxynucleotides and the effects on the haematopoietic colony formation were examined. Treatment of the cells to Hox 2.3 antisense oligodeoxynucleotides led to a selective inhibition of myeloid colony formation, both in size and in numbers, but without significant effect on erythroid and megakaryocytic haematopoiesis. Exposure to Hox 2.3 sense oligodeoxynucleotides (no-oligomers), had no such effect. It was further showed that inhibition of myelopoiesis by Hox 2.3 antisense oligodeoxynucleotides was dependent on the differentiation stage of target cells. These findings demonstrated that Hox 2.3 gene plays a critical role in regulating normal murine myelopoiesis.

Animals↗
PubMed1992

Localization of the gene for MEN 2A.

The search for the gene that causes the multiple endocrine neoplasia type 2A (MEN 2A) syndrome is entering a new phase. Genetic linkage studies have localized the gene to the pericentromeric region of chromosome 10. The statistical portion of mapping the gene for MEN 2A is nearly complete and now classical molecular biological/gene mapping techniques will be employed. We have used fluorescence in situ hybridization to estimate the size of the MEN2A region to be about 2 to 5 mb, using some liberal assumptions; at worst the region should contain no more than about 10 mb of non-alphoid DNA. Our mapping panels (meiotic recombinant and radiation reduced hybrid) give consistent orders of markers in this small region. We describe our initial attempts to clone the region using yeast artificial chromosomes.

Chromosome Mapping↗
PubMed1992

Expression and purification of the alpha and beta subunits of Drosophila casein kinase II using a baculovirus vector.

Two recombinant baculoviruses that express the alpha and beta subunits of Drosophila melanogaster casein kinase II, respectively, have been constructed. The expressed proteins are similar to the authentic Drosophila subunits in size and are recognized by antisera raised against the Drosophila holoenzyme. Extracts derived from cells infected with the alpha subunit-expressing virus display elevated casein kinase II activity in vitro. This activity is markedly enhanced in extracts of cells infected with both viruses, or when alpha and beta subunit-containing extracts are mixed in vitro following lysis. Recombinant holoenzyme and the alpha subunit were purified to near homogeneity using phosphocellulose column chromatography. The specific activity of the purified recombinant holoenzyme was very similar to that of the native enzyme, and was fivefold higher than that of the purified free alpha subunit. The Stokes radius of the recombinant holoenzyme was estimated to be 50 A, a value similar to that reported for the native enzyme, whereas the alpha subunit demonstrated a Stokes radius of 26.5 A. Studies using sucrose density gradient centrifugation showed that, under conditions of high ionic strength, the quaternary structure of the purified holoenzyme was tetrameric (like the native enzyme), whereas the structure of the alpha subunit was monomeric. At lower ionic strength the recombinant holoenzyme had a significantly higher sedimentation coefficient, characteristic of the formation of filaments found for the native enzyme. Interestingly, the purified catalytic subunit also displayed a higher S value under conditions of low ionic strength, revealing the formation of alpha subunit aggregates.

Animals↗
PubMed1992

Effects of atropine on the changes of pain threshold and contents of leucine-enkephalin and catecholamines of the brain in rats induced by EA.

After rats received electroacupuncture (EA), leucine-enkephalin (LEK) content in striatum and dopamine (DA) concentration in both brain stem and diencephalon markedly increased, and noradrenaline (NA) level in telencephalon definitely decreased with an obvious elevation of pain threshold. However, a previous intraperitoneal injection of atropine, a blocker of muscarinic receptor, not only partially blocked the analgesic effect of EA, but also changed the effects of EA on LEK, NA and DA contents of the brain. The results indicate that cholinergic system plays an important role in electroacupuncture analgesia (EAA), which may be fulfilled partially through the central LEK and catecholamine (CA) systems.

Animals↗
PubMed1992

[IL-2 potentiates the IL-3 production by ConA activated mouse splenic T cells].

In addition to the regulation of T cell growth, IL-2 exerts effects on the induction of certain lymphokines. We show here that IL-2 synergizes with 5 micrograms/ml of ConA to promote the production of IL-3 in mouse splenic T cell cultures. IL-3 was measured as CFU-GEMM-inducing activity on mouse bone marrow progenitor cells in the supernatant of the stimulated mouse splenic T cells (TCM). The resting T cells produced no CFU-GEMM-inducing activity, but could be induced to produce low level of CFU-GEMM-inducing activity in the presence of ConA. In vitro exposure to IL-2 markedly increased CFU-GEMM-inducing activity production (nearly up to 8-fold) by the ConA-activated T cells. Optimal stimulation was observed when 80 u/ml IL-2 was used for 48 h incubation. Anti-mouse IL-3 monoclonal antibody inhibited the CFU-GEMM inducing activity of TCM. Moreover, the TCM stimulated the proliferation of IL-3 dependent cell line FDC-P1. We also show that IL-2 and ConA-treated T cells expressed high level of IL-3 mRNA through dot blot analysis. These results confirmed the nature of CFU-GEMM-inducing activity of TCM as IL-3. The capacity of IL-2 to promote the production of IL-3 may represent an important mechanism by which it mediate the communication between the immune and hematopoietic systems.

Animals↗