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Biomedical subjects

J Gu

Publications and source records attributed to J Gu.

At least 253 records · Page 14Linked to original sources
PubMed1995

[Effect of scopolamine on the contents of beta-endorphin and oxytocin in hypothalamus, pituitary and plasma in morphine dependent rats].

Male Sprague-Dawley rats weighing 180-220 g were rendered dependent on morphine by repeated injections of morphine in increasing doses for 14 days. 0.3 mg/kg of scopolamine was injected intraperitoneally bid for 3 and 4 days. Control rats were similarly injected with saline. The contents of beta-endorphin (beta-EP) and oxytocin (OT) in hypothalamus, pituitary and plasma were measured by radioimmunoassay. The results showed that both beta-EP and OT in hypothalamus and plasma increased but both were decreased in pituitary in morphine dependent rats (P < 0.01). After scopolamine treatment, the contents of beta-EP increased but OT decreased in hypothalamus (P < 0.01), and both elevated significantly in pituitary (P < 0.01). The results suggested that scopolamine might modulate hypothalamus-pituitary system to affect the release or synthesis of beta-EP and OT in the brain.

Animals↗
PubMed1995

A study of biological function of retinoblastoma gene (Rb gene).

The human wild-type Rb gene cDNA has been cis- or trans inserted into the retrovirus vector DOL, resulting in a sense-expression vector DOLRB and an antisense-expression vector DOLRBAS of Rb gene. By eletroporation transfection techniques, the vector DOLRB has been introduced into the human breast carcinoma cell line MDAMB468 and human hepatocellular carcinoma cell line SMMC7721 both of which have an inactivated Rb gene and the vector DOLBAS, into normal human embryonic lung fibroblasts HEL cells. With the expression of Rb protein, the growth rate of the MDAMB468 cells is decreased by about 50%, their colony formation ability in soft agar is repressed completely, and their tumorigenicity in nude mice is repressed partially. Meanwhile, the cell population of G1 phase of Rb+ MDAMB468 cells is increased markedly. About 75% of transfected SMMC7721 cells have been killed by Rb gene product. For HEL cells, with the transient expression of antisense Rb gene, the Rb protein synthesis is reduced and the growth rate of those cells increased, but no colonies of HEL cells are formed in soft agar.

Animals↗
PubMed1995

Normothermic retrograde cardioplegia is effective in patients with left ventricular hypertrophy. A prospective and randomized study.

Twenty patients with left ventricular hypertrophy (LVH) undergoing isolated aortic valve replacement were prospectively randomized to receive either continuous retrograde normothermic (n = 8) or intermittent retrograde hypothermic (n = 12) methods of myocardial protection. Biopsies of the left ventricular septum were evaluated for ultrastructure and assayed for ATP. There was no mortality, no requirement for intra-aortic balloon pump nor neurological events in any of the patients from either group. Myocardial ATP (warm 23.2 +/- 1.8 nmol/mg protein; cold 22.4 +/- 1.2 nmol/mg protein; p = 0.72) and myocardial CPK-MB (warm 43.6 +/- 5.2 U/l; cold 39.0 +/- 2.5 U/l; p = 0.67) were not significantly different. Ultrastructure was generally well preserved in the biopsies from both groups, with the exception of one patient in the normothermic group. Systemic lactate sampled after 40 minutes of cardiopulmonary bypass was significantly higher in the normothermic group (warm 3.4 +/- 0.27 mmol/l; cold 2.3 +/- 0.21 mmol/l; p = 0.01), however, the myocardial lactate production was not significantly different between the two groups (extraction ratio; warm 0.01 +/- 0.3; cold 0.13 +/- 0.1; p = 0.45). We conclude that the continuous normothermic retrograde method of myocardial protection is effective in patients with left ventricular hypertrophy; however, the higher systemic lactate levels using this technique raises concerns regarding the adequacy of systemic perfusion at 37 degrees C.

Aged↗
PubMed1995

[Experimental research on using macromolecule sodium hyaluronate to prevent flexior tendon adhesion].

With chicken paw as an animal model, we studied the effects of sodium hyaluronate product (SHP) on the heal of injured tendon and the formation of post-surgical tendon adhesions. The function of digit flexion angle and moving function of the tendon in SHP group were remarkably superior to those of tendons in physiological salt solution control group (P < 0.01). Tendons of the experiment group healed well, their surface was smooth without adhesion. False sheath was formed around the tendon, and there was also a gap between the false sheath and the tendon. However, the adhesion between the tendon and its surrounding tissue in the control group was donse with clear boundary. These results suggest that SHP has a protective effect against the formation of adhesion in healing tendon.

Animals↗
PubMed1995

[Analysis of 145 hepatic disorders from autopsy cases of children].

A statistical analysis was made on 145 cases of hepatic disorders from 2659 autopsies in children. The results showed that hepatic disorders accounted for 5.5% (ranking fourth) of the various systemic disorders. Viral hepatitis was the most common entity (55.2%) with cirrhosis following (20.7%). Most of the hepatic disorders occurred under 1 year of age, accounting for 70.34% of total. The annual detection rate of viral hepatitis showed an increasing trend, demonstrating that hepatic disorders, especially viral hepatitis, are the major diseases that threaten the life of children.

China↗
PubMed1994

A panel of radiation hybrids for human chromosome 8.

We have developed a panel of radiation hybrids containing fragments of chromosome 8 as the only human material. The human chromosome content of each cell line was determined relative to an ordered map of sequence tagged sites (STSs) specific to chromosome 8. Between one and four fragments of chromosome 8 were identified in each cell line, with an average of 25% of the STSs retained in each line. Subclones of one radiation hybrid were examined to determine whether all cells within a line are homogeneous with respect to chromosome 8 sequence content. There was considerable variability between subclones, with retention rates for individual STSs ranging from 5 to 100% in different clones. Furthermore, a gradient of retention of sequences along the length of one large chromosome fragment was found, suggesting that sequence loss involved deletions from one end of the fragment at early stages in the establishment of the cell line. We have also made use of the radiation hybrids to develop novel sequence tagged sites for the pericentromeric region of chromosome 8.

Adenine Phosphoribosyltransferase↗
PubMed1994

T.C.G triplet in an antiparallel purine.purine.pyrimidine DNA triplex. Conformational studies by NMR.

The antiparallel purine.purine.pyrimidine DNA triplex, RRY6, which contains a T.C.G inverted triplet in the center of the sequence, was examined by proton and phosphorous two-dimensional NMR spectroscopy. The local conformation of the T.C.G triplet (T4.C11.G18) and the effect of this triplet on the global helical structure were analyzed in detail. The formation of the T.C.G triplet is confirmed by a set of cross-strand NOEs, including unusual cross-strand NOEs between the third strand and the pyrimidine strand as opposed to the purine strand of the duplex. NMR data suggest that the T.C.G triplet may be present in an equilibrium between a non-hydrogen-bonded form and a T(O4)-C(NH2) hydrogen-bonded form and that there is a distortion of the in-plane alignment of the three bases. The flanking G.G.C base triplets are well-defined on the 5'-side of T4, but somewhat interrupted on the 3'-side of T4. The effect of the third strand binding on the Watson-Crick duplex was probed by an NMR study of the free duplex RY6. NMR parameters are affected mostly around the T.C.G inversion site. The perturbations extend to at least two adjacent base triplets on either side. The binding of the third purine strand and the accommodation of a central T.C.G inversion in RRY6 does not require a readjustment in sugar pucker, which remains in the range of C2'-endo. 31P resonances of RRY6 distribute over a range of 2.2 ppm. The H-P coupling patterns of the third strand differ from those of the duplex. General spectral patterns defined by the marker protons of the RRY and YRY triplexes are compared.

Base Sequence↗
PubMed1994

cDNA cloning and chromosomal mapping of human N-acetylglucosaminyltransferase V+.

Human N-acetylglucosaminyltransferase V (GnT-V, EC 2.4.1.155) cDNA was isolated from a human fetal liver cDNA library. Oligonucleotide primers for polymerase chain reaction were designed according to the amino acid sequence of human GnT-V. Screening for the cDNA was carried out by plaque hybridization using PCR products of about 500 bp. Human GnT-V has 741 amino acids and six putative N-glycosylation sites. The homology to rat GnT-V is 88% at the nucleotide level and is 97% at the amino acid level, and there is one amino acid insertion. Using the cDNA clones as probe, five overlapping genomic clones have been isolated from a human phagemid DNA library. The GnT-V gene has been mapped to chromosome 2q21 using fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1994

Diagnosis of carbohydrate-deficient glycoprotein syndrome by matrix-assisted laser desorption time-of-flight mass spectrometry.

Serum transferrin from patients with carbohydrate-deficient glycoprotein syndrome was analysed by matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF mass spectrometry). Abnormal molecular species with a defect of one or two oligosaccharide chains of 2200 Da were clearly identified. MALDI-TOF mass spectrometry will serve to diagnose this aetiologically unknown, metabolic disease.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1994

Electrospray ionization mass spectrometry of pyridylaminated oligosaccharide derivatives: sensitivity and in-source fragmentation.

Oligosaccharide chains fluorescence-labelled at their reducing end with 2-aminopyridine were analysed by electrospray ionization mass spectrometry (ESIMS). Protonated molecules of complex type oligosaccharides were detectable at a level of 1 pmol. Fragmentation at the glycosidic bonds occurred in the electrospray ion source when the voltage between the capillary nozzle and the first skimmer was elevated, referred to as "in-source fragmentation". Most fragment ions observed had retained the pyridylaminated (PA) site of the molecule and gave significant information on the saccharide sequence. In conjunction with the accumulating data of reversed-phase chromatography of PA oligosaccharides, ESIMS of PA oligosaccharide will be useful as a sensitive method in the structural study of oligosaccharides from various biological sources.

Carbohydrate Sequence↗
PubMed1994

Basal and inducible transcriptional activity of an upstream AP-1/CRE element (DYNCRE3) in the prodynorphin promoter.

During chronic pain and inflammation, prodynorphin gene expression is elevated in the spinal cord. To characterize the molecular regulation of prodynorphin gene expression, we examined an AP-1/CRE-like element, TGCGTCA, located at -1545 in the prodynorphin gene (the DYNCRE3 site). Previous work in our laboratory demonstrated by gel shift analysis that Fos and non-Fos-containing complexes formed with oligonucleotides containing this element. To examine the functional significance of this site, constructs containing variable length regions of the prodynorphin promoter were transiently transfected into PC12 or HeLa cells. Constructs containing the DYNCRE3 site consistently permitted higher levels of transcriptional activity than those lacking this site. Furthermore, placement of upstream regions containing the DYNCRE3 site adjacent to the minimal promoter yielded transcriptional activity much greater than that in the presence of the native constructs. PC12 cells transfected with constructs containing the DYNCRE3 site responded to a far greater degree to forskolin stimulation than those transfected with constructs that did not contain this site. Mutation of the DYNCRE3 site (CTcgtca) markedly reduced forskolin-induced increases in transcriptional activity. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate produced little or no change in transcriptional activity. By examining successively more isolated fragments of prodynorphin promoter and by mutational analysis, we identify and characterize a 7-bp site, DYNCRE3, which, though largely unaffected by stimulations of the PKC pathway, dramatically responds to stimulations via the PKA second messenger pathway.

Animals↗