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Biomedical subjects

M Wu

Publications and source records attributed to M Wu.

At least 505 records · Page 28Linked to original sources
PubMed1990

Cloning and characterization of chloroplast ribosomal protein-encoding genes, rpl16 and rps3, of the marine macro-algae, Gracilaria tenuistipitata.

In Gracilaria tenuistipitata, a highly differentiated multicellular member of the marine red algae, Rhodophyta, chloroplast (cp) DNA can be separated as a satellite band from the nuclear DNA in a CsCl gradient. Using a heterologous probe from Chlamydomonas, the ribosomal protein-encoding gene, rpl16, was located on a 4.5-kb EcoRI fragment of cp DNA. The fragment was cloned and a 1365-bp region around rpl16 was sequenced. The gene order around rpl16, 5' rpl22-rps3-rpl16, is identical to that detected in the chloroplast DNA of liverwort, tobacco and maize. Both the nucleotide sequence and the amino-acid sequence of rpl16 are more conserved than that of rps3. The rpl16 gene contains no intron, a feature which shows more similarity to the unicellular green algae, Chlamydomonas, than to other land plants. Sequences that may form a stable stem-loop structure were detected within the coding sequence of rpl16.

Amino Acid Sequence↗
PubMed1990

A ferredoxin-type iron-sulfur protein gene, frx B, is expressed in the chloroplasts of tobacco and spinach.

Previously, a ferredoxin-type iron-sulfur protein, frx B protein, was identified in a high-salt extract of the purified thylakoid membrane of Chlamydomonas reinhardtii, a unicellular green alga. Polyclonal antibody was raised against a synthetic pentadecameric peptide with an amino acid sequence corresponding to the highly conserved region of the putative frx B proteins of 3 land plants. In this report, protein(s) reacting strongly and specifically with this antibody was detected in the equivalent high-salt extract prepared from purified chloroplast of spinach and tobacco. One strong reaction polypeptide band from tobacco chloroplast was purified from SDS-polyacrylamide gel and subjected to endoproteinase lys C digestion. The resulting polypeptides were separated by reversed-phase chromatography. N-terminal sequencing of 3 purified polypeptides revealed that the protein is encoded by the 'frxB gene' identified from DNA sequence analysis.

Amino Acid Sequence↗
PubMed1990

Comparison of effects of magnesium valproate and sodium valproate on the action potential of isolated papillary muscle from guinea pigs and dogs.

A comparison of the effects of magnesium valproate (MV) and sodium valproate (SV) on the action potential of isolated papillary muscle from guinea pigs and dogs was made in this study. The results in both animals were as follows: MV and SV induced a slight reduction of slope plateau of action potential and prolongation of action potential duration (APD). What is more, APD50 and APD90 were prolonged significantly, thus the ratio of APD90/APD25 was increased. The effective refractory period (ERP) was prolonged significantly. MV or SV showed no effects on action potential amplitude, overshoot, resting potential and phase 0 upstroke velocity. The above results suggested that MV and SV might play an antiarrhythmic role and that their effects were analogic. The mechanism of MV and SV inducing significant prolongation of APD50, APD90, and ERP, might be closely related to the slow-down of the velocity of K+ efflux during plateau and repolarization of phase 3 by radical of valproate and the slow-down of velocity of K+ efflux of repolarization of phase 3 in particular. These results showed that there was no difference in SV and MV action on guinea pigs and dogs.

Action Potentials↗
PubMed1990

Ecdysteroids affect in vivo protein metabolism of the flight muscle of the tobacco hornworm (Manduca sexta).

Ecdysteroid growth promotion of the dorsolongitudinal flight muscle of Manduca sexta was studied by measuring in vivo protein metabolism using both "flooding-dose" and "non-carrier" techniques. These procedures differ in that the former method includes injection of non-labelled phenylalanine (30 micromoles/insect) together with the [3H]amino acid. Injected radioactivity plateaued in the haemolymph within 7 min. With the flooding-dose method, haemolymph and intramuscular specific radioactivities were similar between 15 min and 2 h. Incorporation of [3H]phenylalanine into muscle protein was linear with either method between 30 and 120 min. Fractional rates (%/12 h) of synthesis with the flooding-dose technique were best measured after 1 h because of the initial delay in radioactivity equilibration. Estimation of body phenylalanine turnover with the non-carrier method showed 24-53%/h which was negligible with the flooding-dose method. Since the two methods yielded similar rates of protein synthesis, the large injection of non-labelled amino acid did not alter the rate of synthesis. Because the flooding-dose technique requires only a single time point measurement, it is the preferred method. The decline and eventual cessation of flight-muscle growth was mostly a consequence of declining protein synthesis though degradation increased between 76-86 h before eclosion and was relatively rapid. This decline in muscle growth could be prevented by treating pupae with 20-hydroxyecdysone (10 micrograms/insect). Protein accretion was promoted by a decline of up to 80% in protein breakdown, which was offset in part by a concurrent though much smaller decrease in protein synthesis. Therefore, ecdysteroids may increase flight-muscle growth by inhibiting proteolysis.

Animals↗
PubMed1990

Selective killing of tumor cells in vitro by an immunotoxin composed of ricin and monoclonal antibody against Ia antigen.

A monoclonal antibody (MAb-HB55) directed against a HLA class II antigen (Ia), was purified by DE-52 chromatography. The purified MAb contained less than 5% impure protein detected by SDS-PAGE. Ricin was conjugated with the MAb via a disulfide bond to construct an immunotoxin (ricin-HB55). The concentration causing fifty percent growth inhibition (IC50) was 2 x 10(-11)M for the Raji cells. In contrast, the IC50 for Molt-4 and K562 cells was 100 times higher than that for the Raji cells. B lymphocytes separated from peripheral blood lymphocytes by nylon wool were selectively killed by the conjugate, but T lymphocytes were not apparently affected. Our results demonstrate that the immunotoxin is selectively cytotoxic to Raji cells and B-cells, and may have potential for purging malignant cells from bone marrow of patients with B-cell leukemia and lymphoma.

Ammonium Chloride↗
PubMed1990

Protection against gram-negative bacteremia in neutropenic mice with recombinant granulocyte-macrophage colony-stimulating factor.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates production of neutrophils in bone marrow and may decrease the incidence of infection during neutropenia. We evaluated the protective role of recombinant GM-CSF against Pseudomonas aeruginosa challenge in neutropenic mice. CD-1 mice treated with cyclophosphamide on days 1 and 2 of the experiment were given GM-CSF (1, 2, or 4 micrograms/day) starting at day 4 of the experiment according to the following protocol: 1) 1 microgram of GM-CSF 2 hr and 24 hr after challenge; 2) 1 microgram 24 hr before challenge, 2 hr and 24 hr after challenge; 3) 2 micrograms injected 24 hr before and 2 hr after challenge; 4) 2 micrograms given 24 hr before and 2 micrograms given 2 hr and 24 hr after challenge; 5) 4 micrograms administered 2 hr and 24 hr after challenge; and 6) saline and bovine albumin controls. The number of blood neutrophils by days 4 and 5 was similar for GM-CSF-treated and untreated animals. Survival was significantly greater in animals given 2 micrograms of GM-CSF at 24 hr before and at 2 hr and 24 hr after challenge with Pseudomonas. Neutrophils and splenic macrophages obtained from GM-CSF-treated mice (2 micrograms/animal) produced significantly greater amounts of O2- (204 +/- 36 nmoles/10(5) cells) than controls (21 +/- 10 nmoles/10(5) cells). Additionally, neutrophils and macrophages from GM-CSF-treated mice killed significantly more bacteria (P. aeruginosa) in vitro and had a greater number of C3b and Fc receptors (78 +/- 12% and 89 +/- 8%) than did cells obtained from control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Learning needs of patients with angina: an extension study.

This study compares the learning needs of patients diagnosed with coronary artery disease who experience angina with ratings by the patients themselves and the nurses who care for them. Also compared are the rankings done on categories of select learning needs with rankings done on categories of actual or intended adherence to prescribed medical regimens, using data obtained from the patients. Samples consisted of 15 telemetry unit nurses, 15 inpatients with angina, and 15 postdischarge patients with angina. All participants responded to the Cardiac Patient Learning Need Inventory and a demographic data sheet. Patients also responded to the Educator Preference Tool and either the Health Intention or Health Behavior Scale. Data analysis indicated that similarities and differences existed between patients and nurses in what they believed is important for patients to learn. Patients expressed a greater preference for physicians, rather than nurses, to teach them cardiac information. The findings indicate that what patients believe is most important to learn, as indicated by select learning needs categories, is related to what they most intend to do or actually adhere to regarding their medical regimen.

Adult↗
PubMed1990

Dietary orotic acid accentuates the hepatic response to phenobarbital in rats.

In rats treated with phenobarbital for 3 days and simultaneously fed a semisynthetic diet containing 1.0% orotic acid, the extent of the increases in liver microsomal phosphatidylcholine, phosphatidylethanolamine, total RNA, total protein, and cytochrome P-450 were significantly greater than they were in rats treated identically with phenobarbital but without dietary orotic acid. This is attributed primarily to the stimulation of hepatic phosphatidylcholine synthesis by dietary orotic acid. In the absence of phenobarbital, orotic acid was shown to cause some increase in liver smooth endoplasmic reticulum components, but not cytochrome P-450. Orotic acid also decreased the activity of microsomal phosphatidylethanolamine N-methyltransferase, which may have contributed to the increase in the microsomal content of phosphatidylethanolamine. The hypothesis is advanced that phospholipid availability is a limiting factor in the hepatic response to phenobarbital. When more phospholipid is available to provide the structural framework for biogenesis of endoplasmic reticulum, all of the hepatic actions of phenobarbital, including induction of cytochrome P-450, are amplified.

Animals↗
PubMed1990

[Physico-chemical characterization of human seminal plasma specific antigen p30].

Human seminal plasma specific antigen p30, which has been characterized by other authors under the name of prostate-specific antigen or gamma-seminoprotein, has been purified. This communication describes the physico-chemical characterization of p30 demonstrated by various SDS-polyacrylamide gel electrophoresis and isoelectrofocusing as well as amino acid analysis. The results showed that the molecular weight of p30 was 33 kd and its isoelectric point was around pH 6.9. Its amino acid composition was similar to that of prostate-specific antigen. It is concluded that p30 purified by our laboratory and prostate-specific antigen named by Wang are the identical one of isomers.

Amino Acids↗
PubMed1990

Effect of stress-related hormones on macrophage receptors and response to tumor necrosis factor.

Tumor Necrosis Factor (TNF) has been implicated in the early metabolic events following acute tissue injury or sepsis; it increases blood levels of glucocorticoids and glucagon or the cellular responses to the hormones. To examine whether stress-related hormones have any effect on macrophage activation by TNF, human monocyte-derived macrophages were exposed to somatostatin (S), ACTH, angiotensin (An), insulin (I), epinephrine (E), and glucagon (G) at physiologic concentrations. 125I-TNF binding as well as the ability of TNF to activate macrophages to kill an intracellular pathogen (Mycobacterium avium) were measured. While treatment with recombinant interferon gamma increased the number of TNF receptors by 53 +/- 8%, E, I, G, S, ACTH and An decreased the number of receptors by 81 +/- 6%, 83 +/- 6%, 15 +/- 5%, 83 +/- 4%, 17 +/- 4% and 21 +/- 4%, respectively. Treatment with I, E, and S also decreased the ability of macrophages to kill M. avium by 30 +/- 1%, 20 +/- 6%, and 51 +/- 2%, respectively. These in vitro results suggest that stress hormones influence TNF-mediated activation of macrophages.

Adrenocorticotropic Hormone↗
PubMed1990

Isolation, characterization and expression of the complementary DNA for human tumor necrosis factor (TNF-alpha).

A cDNA for human TNF-alpha (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-alpha. Approximately 80,000 units of activity were detected per ml of culture at A600 = 2.

Animals↗
PubMed1990

[Human sex identification in dried bloodstains by analysis of amplified DNA sequences].

This paper describes a technique of DNA amplification in vitro and its application on sex identification of human dried bloodstains. Dried bloodstains (8 males and 8 females) were prepared on filter paper, and then DNA was extracted. Target DNA sequences (Y-3.4kb repeat and Alu-repeat) were amplified by polymerase chain reaction (PCR) with two pairs of primers (Y1.1, Y1.2 and Alu9.1, Alu9.2). Amplification products were obtained in 8 male's bloodstains with the primers Y1.1 and Y1.2, but not in 8 female's bloodstains; and in 4 male's and 4 female's bloodstains with Alu9.1 and Alu9.2.

Base Sequence↗
PubMed1990

[The measurement of p30 level in the normal human seminal plasma by the Beckman immunochemistry system using anti-30 serum].

This paper is the first report about the measurement of p30 level in the normal human seminal plasma by the Beckman immunochemistry system (ICS) using anti-p30 serum. The p30 levels of 108 samples of normal human seminal plasma were measured. The range of p30 level was 0.2996-4.3913 mg/ml. The square root transformation statistical analysis indicated that the coefficient of skewness was 0.0237 the coefficient of kurtosis was -0.8854, the p30 level in normal human seminal plasma fitted the square root normal distribution, the mean was 1.6236 mg/ml and the standard deviation was 0.1641 mg/ml.

Humans↗