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W Qi

Publications and source records attributed to W Qi.

85 records · Page 5Linked to original sources
PubMed1993

Transformation of Escherichia coli with foreign DNA by electroporation.

Electroporation has been widely applied in molecular biology in recent years. In this study, successful transformation of plasmid DNA and transfection of phage DNA into E. coli were described by using intense electrical field of exponential decay waveform (electroporation) generated by a Gene Pulsar LN-101 (made in Tianjin, Tianjin Institute of Technology and Nankai University). We have obtained 10(9)-10(10) transformants/micrograms with strain DH5 alpha and plasmid pUC18, by a single voltage pulse at 1.0-2.5 kV (initial electric field strength = 2.8-16 kV/cm) with 5-20 microF capacitor. The efficiency of electroporation depends on various parameters: the electric field strength, capacitance, the pulse length (RC time constant), etc. The frequency of transformation was a linear function of the DNA concentration, as well as the density of recipient cell. The incubation time of before or after electroporation has no significant effect on transformation. The high transfection efficiency was also achieved with strain JM109 and M13mp19RF by electroporation. The method was easier, more time-saving and more efficient than Ca(2+)-dependent transformation (transfection) method. The results obtained by Gene-Pulsar LN-101 was similar to that by the Bio-Rad Gene-Pulsar apparatus.

Calcium↗
PubMed1993

The influence of intermittent positive-pressure ventilation on the cardiorespiratory dynamics of diaphragmatic rupture with gastric herniation.

To determine the effect of intermittent positive-pressure ventilation (IPPV) on gastric herniation in diaphragmatic rupture, 16 piglets underwent laceration of the left hemidiaphragm. Arterial blood gas levels, pulmonary artery wedge pressure, cardiac output and arterial blood pressure were measured. The stomach was then placed above the diaphragm. The initial measurements were repeated, and displacement of the stomach above the diaphragm (S/D) was measured. The animals were divided into two groups: group 1, eight animals breathing 80% oxygen spontaneously and group 2, eight animals receiving IPPV. Initially in group 2 there was only a small decrease in mean (+/- SD) arterial oxygen tension from 484 +/- 34 mm Hg to 424 +/- 20 mm Hg (other parameters were unchanged). In group 1, gastric herniation produced a further fall in arterial oxygen tension to 308 +/- 10 mm Hg at 1 hour, a rise in arterial carbon dioxide tension to 49 +/- 4 mm Hg and a decrease in pH to 7.32 +/- 0.04. In group 2 similar changes in arterial blood gas levels occurred with gastric herniation, but there was a return to baseline values of 490 +/- 28 mm Hg for arterial oxygen tension, 37 +/- 4 mm Hg for carbon dioxide tension and 7.38 +/- 0.05 for pH after IPPV. Similar changes were seen in blood pressure, cardiac output and pulmonary artery wedge pressure. S/D remained at 6.3 +/- 0.2 cm in group 1 but decreased from 6.0 +/- 0.2 cm to 1.1 +/- 0.5 cm after 1 hour in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The cardiorespiratory effects of increased intra-abdominal pressure in diaphragmatic rupture.

The cardiorespiratory effect of gastric herniation in diaphragmatic rupture with and without increased intra-abdominal pressure (produced by inflation of a pneumatic antishock garment [PASG] to an intraperitoneal pressure of 40 mm Hg) was studied in 16 anesthetized spontaneously breathing (80% oxygen) piglets. Four additional animals had similar measurements after PASG inflation but without diaphragmatic rupture. Arterial blood pressure (BP), cardiac output, arterial blood gases, position of the stomach relative to the diaphragm (as measured on fluoroscopy), and mortality were assessed. Gastric herniation without the PASG (group I: 8 animals) produced slight cardiorespiratory deterioration, with PO2 falling from a baseline measurement of 429 +/- 60 mm Hg to 316 +/- 5 mm Hg at 1 hour. Over this period pH decreased from 7.39 +/- 0.05 to 7.30 +/- 0.02 and PCO2 increased from 39 +/- 5 to 46 +/- 2 mm Hg. With PASG inflation (group II: 8 animals) PO2 decreased to a greater extent, from 410 +/- 30 mm Hg at baseline to 48 +/- 10 mm Hg by 1 hour; pH decreased from 7.38 +/- 0.06 to 6.8 +/- 0.2 and PCO2 increased from 39 +/- 4 to 88 +/- 6 mm Hg. Animals without diaphragmatic rupture (group III: 4 animals) showed a smaller decrease in PO2, from 480 +/- 34 mm Hg at baseline to 320 +/- 50 mm Hg by 1 hour after PASG inflation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1992

[Isolation and characterization of prolactin messenger RNA from bovine anterior pituitary glands].

The messenger RNA was extracted from bovine anterior pituitary glands and was purified by oligo(dT)-cellulose chromatography. The length of the mRNA was 1,200 nucleotides measured by agarose gel electrophoresis containing methylmercury hydroxide. The bovine prolactin (PRL) mRNA was confirmed by Northern blot analysis of the mRNA with gamma-32P labelled synthetic oligonucleotide probes based on the partial amino acid sequences of bovine PRL and could stimulate the incorporation of 35S-methionine into protein in the rabbit reticulocyte cell-free system. The translation product of bovine PRL mRNA was immunoprecipitable by rabbit anti-ovine PRL anti-antibodies. The molecular weight of the translation product corresponding to the bovine PRL precursor was estimated to be approximately 25,000 by SDS polyacrylamide gel electrophoresis and autoradiograph.

Amino Acid Sequence↗
PubMed1992

Clinical presentations of gastrointestinal inflammatory fibroid polyps.

Two cases of inflammatory fibroid polyps are described. They involved the uncommon sites of the terminal ileum and ileocecal region respectively. Both lesions, although benign, presented as possible malignant tumours. One was associated with anemia and the other with obstructive symptoms. From a review of the literature and the two case reports the authors believe that the diagnosis of such inflammatory fibroid polyps, on clinical and gross appearance, can be difficult, and they emphasize the importance of awaiting histologic assessment before proceeding with extensive definitive surgery.

Aged↗
PubMed1991

Natural killer target molecules associated with the transformation of the oncogene-transfected fibroblast.

Cell surface antigens, the expression of which is highly enhanced along with the transformation of cells, were analyzed. W14 and W31, EJ-ras oncogene-induced transformants of a WKA rat fetus-derived fibroblast WFB, strongly expressed several transformation-associated antigens as defined by monoclonal antibodies 109, 061, and 081. These monoclonal antibodies recognized Mr 86,000, 62,000, and 101,000 molecules, each composed of a single polypeptide chain. The expression of these transformation-associated antigens was negligible on parental WFB cells. Transforming growth factor-beta could enhance the expression of all of these transformation-associated antigens, but platelet-derived growth factor could only enhance the Mr 86,000 kd molecule expression. In the cytotoxicity assays, poly-I:C-induced rat splenic NK cells were cytotoxic to W14 and W31, but not to WFB. The data also showed that the cytotoxicity by these NK cells against NK-sensitive YAC-1 cells was absorbed with the addition of W14, W31, platelet-derived growth factor, or transforming growth factor-beta-stimulated WFB cells. This indicates that NK cells may recognize common target antigens that are expressed among these target cells. It was also indicated that Mr 86,000 and 62,000 molecules were strongly involved in this cytotoxicity, possibly as the target antigens, since F(ab')2 fragments of monoclonal antibodies 109 and 061 strongly inhibited the cytotoxicity. The addition of monoclonal antibody 109, but not 061, inhibited the cytotoxicity even at 60 min after mixing with the effector and target cells, suggesting that the Mr 86,000 molecule may participate in the lethal hit phase of cytotoxicity by NK cells. These data may indicate that some, but not all, transformation-associated antigens are virtually important in the antitumor surveillance mechanisms by the host effector cells, such as NK cells.

Animals↗
PubMed1991

Gum arabic glycoprotein is a twisted hairy rope : a new model based on o-galactosylhydroxyproline as the polysaccharide attachment site.

Separation of the wound exudate from Acacia senegal (L.) Willd., "gum arabic," on a preparative Superose-6 column gave two major fractions: a high molecular weight gum arabic glycoprotein (GAGP) containing about 90% carbohydrate and a lower molecular weight heterogenous gum arabic polysaccharide fraction. Hydrogen fluoride-deglycosylation of GAGP gave a large ( approximately 400 residue) hydroxyproline-rich polypeptide backbone (dGAGP). Alkaline hydrolysis of GAGP showed that most of the carbohydrate was attached to the polypeptide backbone as small ( approximately 30 residue) hydroxyproline (Hyp)-polysaccharide substituents. After partial acid hydrolysis of the Hyp-polysaccharide fraction we identified O-galactosylhydroxyproline as the glycopeptide linkage, identical with that of hydroxyproline-rich arabinogalactan-proteins (AGPs). However, unlike the acidic alanine-rich AGPs, GAGP is basic and notably deficient in alanine. Thus, while the GAGP polypeptide backbone more closely resembles that of the Hyp-rich cell wall protein extensin, the GAGP polysaccharide sidechains resemble AGPs. Possibly all three proteins comprise a phylogenetically related extensin superfamily of extended rod-like macromolecules. The "wattle-blossom" model for AGP and gum arabic predicts a few large polysaccharide substituents along the polypeptide backbone of a spheroidal macromolecule. On the contrary, our data imply a rodlike molecule with numerous small polysaccharide substituents (attached to 24% of the Hyp residues), regularly arranged along a highly periodic polypeptide backbone based, hypothetically, on a 10 to 12 residue repetitive peptide motif. Thus, a simple statistical model of the gum arabic glycoprotein predicts a repeating polysaccharide-peptide subunit of about 7 kilodaltons. The small polysaccharide substituents will maximize intramolecular hydrogen bonding if aligned along the long axis of the molecule, forming in effect a twisted hairy rope. Electron micrographs of rotary shadowed GAGP molecules support that prediction and may also explain how such apparently large molecules can exit the cell by endwise reptation through the small pores of the primary cell wall.

Journal Article↗
PubMed1990

[Determination of soluble mercury contents in Chinese traditional patent medicines for children].

Soluble mercury contents in Baochi San, Xiaoer Zhibon Ding and Xiaoer Baishou Dan have been determined using dithizone method. This method has the advantages of short digestion time, clear digestion end point, simple operation and reproducible results. The recovery rate ranges from 98.4 to 103%. The data obtained can be used as a reference for controlling soluble mercury contents in Chinese traditional patent medicines containing cinnabar.

Drug Combinations↗
PubMedDate not supplied

The effects of positive airway pressure and intra-abdominal pressure in diaphragmatic rupture.

Arterial blood gases (80% oxygen), intraperitoneal pressure (IP), stomach position relative to the diaphragm (S/D by fluoroscopy), blood pressure, and cardiac output were monitored in 16 anaesthetized New Hampshire piglets with a 12 cm laceration of the left hemidiaphragm. Group I (8 animals) were spontaneously breathing. Group II (8 animals) had a pneumatic antishock garment (PASG) inflated to an IP of 40 torr for 15 mins followed by positive pressure ventilation (PPV) of 20 cm H2O for 15 min and PPV of 40 cm H2O (PPV-40) for 30 more minutes. All Group I animals survived. Three Group II animals died by 15 min after PASG inflation. Seven Group I animals showed no displacement of the stomach above the diaphragm. Blood pressure, cardiac output, and blood gases remained unchanged in Group I compared to baseline with pO2 varying from 436 +/- 44 torr to 417 +/- 31 torr, pCO2 from 38 +/- 1 torr to 39 +/- 1 torr, and pH 7.4 +/- 0.02. Blood pressure in Group I was 109 +/- 3 torr at baseline to 110 +/- 2 torr at 60 mins, and baseline cardiac output was 3.9 +/- 0.2 L/min and 3.8 +/- 0.2 L/min at 60 min. Group II animals had a baseline arterial pO2 of 423 +/- 15 torr and 100 +/- 15 torr at 15 min after PASG. With PPV-20 arterial pO2 increased to 178 +/- 13 torr and further increased to 230 +/- 9 torr at PPV-40.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMedDate not supplied

Pharmacology and physiology of melatonin in the reduction of oxidative stress in vivo.

This brief resume summarizes the evidence which shows that melatonin is a significant free radical scavenger and antioxidant at both physiological and pharmacological concentrations in vivo. Surgical removal of the pineal gland, a procedure which lowers endogenous melatonin levels in the blood, exaggerates molecular damage due to free radicals during an oxidative challenge. Likewise, providing supplemental melatonin during periods of massive free radical production greatly lowers the resulting tissue damage and dysfunction. In the current review, these findings are considered in terms of neurodegenerative diseases, cancer, ischemia/reperfusion injury and aging. Besides being a highly effective direct free radical scavenger and indirect antioxidant, melatonin has several features that make it of clinical interest. Thus, melatonin is readily absorbed when it is administered via any route, it crosses all morphophysiological barriers, e.g., blood-brain barrier and placenta, with ease, it seems to enter all parts of every cell where it prevents oxidative damage, it preserves mitochondrial function, and it has low toxicity. While blood melatonin levels are normally low, tissue levels of the indoleamine can be considerably higher and at some sites, e.g., in bone marrow cells and bile, melatonin concentrations exceed those in the blood by several orders of magnitude. What constitutes a physiological level of melatonin must be redefined in terms of the bodily fluid, tissue and subcellular compartment being examined.

Aging↗