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Biomedical subjects

Q Zeng

Publications and source records attributed to Q Zeng.

150 records · Page 9Linked to original sources
PubMed1988

Effect of partial portal vein ligation on hepatic regeneration.

To evaluate the effect of portal hypertension and diminished portal venous blood flow to the liver on hepatic regeneration, male rats were subjected to partial portal vein ligation and subsequently to a two-thirds partial hepatectomy. The levels of ornithine decarboxylase activity at 6 h after partial hepatectomy were greater (p less than 0.001) in the rats with prior partial portal vein ligation than in those without portal hypertension. The rats with prior partial portal vein ligation also had greater (p less than 0.005) levels of thymidine kinase activity at 48 h after partial hepatectomy than did those without portal hypertension. Hepatic sex hormone receptor activity was not affected by prior partial portal vein ligation either before or after partial hepatectomy. The reductions in both estrogen and androgen receptor activity observed in the hepatic cytosol after partial hepatectomy were similar to those observed in control animals. These data indicate that animals with portal hypertension having a diminished hepatic portal blood flow have a normal capacity to regenerate hepatic mass following a hepatic resection.

Animals↗
PubMed1987

Mapping of the mouse atrial natriuretic factor gene. Evidence for tight linkage to the Fv-1 locus.

The importance of atrial natriuretic factor (ANF) in the regulation of salt balance and blood pressure is now widely recognized, and it would be extremely informative for both physiologists and molecular biologists to have mutants available that exhibit abnormal expression of this peptide hormone. The most direct mutation would affect the structural gene itself by altering either its coding potential or its regulation. With this aim in mind, it is of considerable interest to accurately determine the chromosomal position of the ANF gene (Anf) in the mouse. This information would permit a comparison with known mutations and provide a means of screening for mutations at this locus. Using recombinant inbred mouse strains, we undertook the mapping of the mouse Anf gene and demonstrated linkage of the gene to the Friend virus susceptibility-1 (Fv-1) locus on chromosome 4. The mapping was performed using a restriction fragment length polymorphism extant between the two parental strains. No recombination event between Anf and the Fv-1 locus was evident in any of the 34 strains tested. The assignment of Anf to this region of chromosome 4 coincides with the reported position of the cribriform degeneration mutation, which includes in its phenotype an abnormal electrolyte distribution. We have, therefore, begun studying this mutation to determine whether a defect in ANF expression is the underlying cause of the phenotype. Thus far, we have found no major DNA rearrangement close to the Anf gene.

Alleles↗
PubMedDate not supplied

Percutaneous implantation of a Port-Catheter System using the left subclavian artery.

PURPOSE: To evaluate the safety and feasibility of a percutaneous Port-Catheter System (PCS) implanted via the subclavian artery (SCA) for regional chemotherapy or chemoembolization of thoracic, abdominal, and pelvic malignant tumors. METHODS: Percutaneous puncture of the SCA was performed in 256 patients with thoracic, abdominal, or pelvic malignant tumors; then a catheter was inserted into the target artery. After the first transcatheter chemotherapy or chemoembolization with an emulsion of lipiodol and anticancer agents, an indwelling catheter was introduced with its tip placed in the target artery and its end subcutaneously connected to a port. RESULTS: The procedure was successfully completed in all 256 cases (100%). The indwelling catheter tip was satisfactorily placed in the target arteries in 242 cases (98%). Complications attributable to the procedure occurred in 20 (7.8%) cases, including pneumothorax (n = 10, 4%), hemothorax (n = 1, 0.4%), infections in the pocket (n = 4, 1.6%), and hematoma at the puncture site (n = 5, 2%). There were no severe sequelae or deaths. The duration of PCS usage was 1-36 months (median 9.5 months). During the course of treatment, occlusion of the target artery occurred in 20 cases (7.8%). Dislocation of the tip of the indwelling catheter occurred in 12 cases (4.7%); in 10 of the 12, the tip of the indwelling catheter was repositioned into the target artery. In all 10 cases no large symptomatic hematomas developed after the PCS was removed. CONCLUSION: Percutaneous PCS implantation via the left SCA, a relatively new procedure, is a safe and less invasive treatment approach than surgical placement for malignancies.

Abdominal Neoplasms↗
PubMedDate not supplied

Target-promoted alkylation of DNA.

Inducible and selective alkylation of DNA was accomplished under neutral conditions by use of a silyl-protected phenol that served as a precursor for a highly reactive quinone methide. As expected, addition of fluoride triggered reaction of a model compound, 3-(tert-butyldimethylsiloxy)-4-[(p-nitrophenoxy)methyl]benzamide, and its oligodeoxynucleotide conjugate. Surprisingly, the silyl phenol was also specifically yet more slowly activated by the environment of duplex DNA in the absence of fluoride. This alternative process was associated with the hybridization of probe and target strands, and single-stranded DNA was unable to induce a similar activation. Therefore, DNA appears to effect its own alkylation by promoting the formation of an electrophilic and nondiffusible intermediate.

Alkylation↗
PubMedDate not supplied

B-cell epitopes recognized by Chinese water buffaloes (Bos buffelus) on the 22 kDa tegumental membrane-associated antigen (Sj-22) of the Asiatic bloodfluke, Schistosoma japonicum.

The 22.6 kDa tegumental membrane-associated antigen of schistosomes is of recognized importance in immunity to schistosomiasis. In China, bovines are known to play an important role in the transmission of Schistosoma japonicum. Ten buffaloes (Bos buffelus) were vaccinated with a recombinant form (reSj-22) of the S. japonicum 22.6 kDa tegumental antigen (Sj-22) and the sera were used to identify and map possible linear B-cell epitopes on this molecule using a series of 18 overlapping synthetic peptides (P1-P18). Sera from all of the ten vaccinated buffaloes reacted strongly with Sj-22 in western blots and in ELISA, while sera from a further ten adjuvant (Quil A) control buffaloes did not. Four peptides (P3, P8, P9 and P10) were predominantly recognized by at least 90% of the buffalo sera. This pattern of recognition is similar to that obtained in a previous study we undertook in mice immunized with the same antigen whereby peptides 3, 8, 9 and 10 were recognized by over 80% of CBA strain mice. The peptide most frequently recognized by mice (peptide 6), and mapping to an EF-hand calcium binding domain, was recognized by six of the ten vaccinated buffaloes. The major difference between buffaloes and mice occurred with peptide 1 which was recognized very frequently by all three strains of mice tested but was only weakly recognized by three of the ten buffaloes. This study provides a valuable reference for further study on the immunity stimulated by the 22.6 kDa tegumental antigen in the murine model and a natural bovine host of Schistosomiasis japonica.

Amino Acid Sequence↗