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Biomedical subjects

Q F Li

Publications and source records attributed to Q F Li.

At least 19 recordsLinked to original sources
PubMed2001

Microdetermination of proteins with the arsenazo-DBN-Al(III) complex by Rayleigh light-scattering technique and application of the method.

The determination of proteins with arsenazo-DBN and Al3+ by Rayleigh light-scattering (RLS) is described. The weak RLS of arsenazo-DBN and BSA can be enhanced greatly by addition of Al3+ in the pH range 5.3-7.0; this resulted in two enhanced RLS signals at 420-440 nm and 460-480 nm. The reaction between arsenazo-DBN, Al3+, and proteins was studied and a new method was developed for quantitative determination of proteins. This method is very sensitive (0.34-41.71 microg mL(-1) for bovine serum albumin, BSA, and 0.29-53.41 microg mL(-1) for human serum albumin, HSA), rapid (< 2 min), simple (one step), and tolerant of most interfering substances. The effects of different surfactants were also examined. When these proteins were determined in four human serum samples the maximum relative error was not more than 2% and the recovery was between 97 and 103%.

Aluminum↗
PubMed2000

Muscle pain activates a direct projection from ventrolateral periaqueductal gray to rostral ventrolateral medulla in rats.

Activation of the ventrolateral periaqueductal gray (vlPAG) evokes a reaction of quiescence, immobility, hypotension and bradycardia. Pain of deep somatic or visceral origin also often triggers a reaction of quiescence, immobility, hypotension and bradycardia and further, evokes a selective increase in immediate-early-gene (c-Fos) expression within the vlPAG. Vasodepression evoked from the vlPAG is thought to be mediated by an inhibition of presympathetic neurons within the rostral ventrolateral medulla (RVLM). In this study the prior injection of retrograde tracer into the RVLM was combined with the use of Fos expression as a marker of neuronal activation, to determine if deep (muscle) pain-evoked vasodepression could be mediated by a direct vlPAG-RVLM pathway. It was revealed that intramuscular injection of formalin, in the anaesthetised rat, evoked a significant increase in Fos expression within the caudal vlPAG, and that approximately 25% of the Fos-immunoreactive neurons projected to the RVLM.

Animals↗
PubMed2000

Accelerated flap prefabrication with vascular endothelial growth factor.

Vascular endothelial growth factor (VEGF) is a potent promoter of angiogenesis that has been shown to enhance revascularization of ischemic tissues, including skin flaps. This study was designed to investigate the value of a single topical application of recombinant human VEGF to accelerate flap viability in a rat model of a non-ischemic prefabricated flap. Prefabricated flaps were created in 48 Sprague-Dawley rats. An autologous tail artery loop was anastomosed to the femoral artery and vein, and implanted subcutaneously in the lower abdomen. Flaps were divided into two groups of 24 each. At the time of loop implantation the control group received 0.9 percent NaCl or a 16 percent vol/wet polyvinyl alcohol (PVA) solution: the treatment group received VEGF in 0.9 percent NaCl or VEGF in PVA. The PVA gel was used to facilitate topical application In each group, 3- x 4-cm flaps nurtured by the tail artery pedicle were elevated and resutured into place after 3, 4, and 5 weeks. The percentage of surviving skin of each flap was determined by planimetry 7 days after flap elevation. Mean skin survival areas at 3, 4, and 5 weeks were control group 0 percent. 8 percent and 17.5 percent; and VEGIF-treated group, 6 percent, 40 percent, and 66.7 percent respectively VEGF significantly improved flap survival by 5 weeks (p = 0.02). These results suggest that VEGF can accelerate maturation of prefabricated flaps. This approach could expand the application of flap prefabrication as a resource for reconstructive surgery.

Animals↗
PubMed2000

Increased detectability of alpha brain glutamate/glutamine in neonatal hypoxic-ischemic encephalopathy.

BACKGROUND AND PURPOSE: Proton MR spectroscopy (MRS) detectability of brain glutamate/glutamine (Glx) is increased in hypoxic-ischemic insults and is implicated in the neuronal injury and death that follows. Our aim was to correlate the proton MRS detectability of alpha-CH protons of Glx (alpha-Glx) with the Sarnat stage of neonatal hypoxic-ischemic encephalopathy (HIE). METHODS: Initial and follow-up proton MRS studies at 1.9 T were performed in 28 neonates aged 1 to 7 days (seven healthy control subjects and 21 with HIE: 10 mild, nine moderate, and two severe) and in 12 neonates aged 13 to 17 days (12 with HIE: eight mild, three moderate, and one severe), respectively. Both point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) sequences were used. The spectral volume of interest was in the basal ganglia, thalami, and adjoining regions. The detectability of alpha-Glx was assessed by two different parameters: the detection rate of the alpha-Glx peak and the peak-area ratio of alpha-Glx to creatine and phosphocreatine. RESULTS: On both the initial and follow-up PRESS studies, all the neonates with moderate and severe HIE showed an alpha-Glx peak, compared with one healthy control subject in the initial study and one neonate with mild HIE in both the studies. They also demonstrated a significantly higher peak-area ratio of alpha-Glx/(creatine and phosphocreatine) on both the initial and follow-up studies. The peak-area ratios in neonates with HIE positively correlated with the Sarnat stage of HIE on both the initial and follow-up studies. Neonates with moderate and severe HIE also showed a consistently higher alpha-Glx peak on both the initial and follow-up studies with the STEAM sequence. CONCLUSION: Proton MRS detectability of alpha-Glx is increased in moderate and severe HIE and correlates with the Sarnat stage of HIE.

Brain↗
PubMed1998

Uncoupling protein mRNA, mitochondrial GTP-binding, and T4 5'-deiodinase activity of brown adipose tissue in Daurian ground squirrel during hibernation and arousal.

The mRNA level of uncoupling protein (UCP) specific for brown adipose tissue (BAT) in Daurian ground squirrel, was detected by using a [32P]-labeled oligonucleotide probe. The UCP concentration in mitochondria was indirectly determined by titration with its specific ligand [H3]-labeled GTP. Type II T4 5'-deiodinase of BAT was assayed concomitantly. We found two species of mRNA for UCP with lengths of about 1.9 and 1.5 kb, respectively, both occurring in almost the same concentration. UCP mRNA content was elevated significantly during hibernation, but the UCP concentration did not change compared with that of nonhibernating controls kept at room temperature. When hibernating squirrels were aroused, the UCP mRNA remained at the elevated level as during hibernation, but the UCP concentration increased in comparison with that of nonhibernating controls or during hibernating. Changes in T4 5'-deiodinase activity in BAT were similar to the variations of the UCP mRNA level. These results suggest that the activation of T4 5'-deiodinase in BAT may be an important factor for the up-regulation and maintenance of UCP mRNA content needed for the synthesis of sufficient UCP to acquire the thermogenic capacity for arousal from hibernation.

Adipose Tissue↗
PubMed1997

Primary human prostate cancer cells harboring p53 mutations are clonally expanded in metastases.

Recent studies suggest a role for p53 in prostate cancer progression. Although p53 mutations in primary prostate cancer tissues are relatively infrequent, they occur at significant levels in metastatic disease. Here we describe a novel approach to the molecular analysis of p53 in paired specimens of primary and metastatic prostate cancer that results in quantitative estimates of the extent of clonal expansion. In 20 pairs with 1 or both specimens p53 immunopositive and in 6 pairs with both specimens immunonegative, the frequency of mutations was estimated by microdissection of the cancer from fixed and sectioned tissues, isolation of the DNA followed by PCR amplification of p53 genomic fragments, and cloning of the PCR products into plasmid vectors. At least 90 clones/tissue specimen were screened for mutations by single-strand conformational polymorphism analysis. DNA from abnormally migrating single-strand conformational polymorphism samples was sequenced to confirm mutations. Missense mutations in exon 5, 7, or 8 were detected in 9 of 20 immunopositive pairs and in 1 of 6 immunonegative pairs. A marked heterogeneity of mutations in primary prostate cancer was apparent. The frequency of p53 mutations was greater in the metastases than in the primary tumors. In three immunopositive pairs, the same p53 mutation was demonstrated at a low frequency in the primary tumor but was demonstrated at a greater frequency in the metastasis, indicating relatively limited clonal expansion of cells harboring specific p53 mutations in the primary tumor, yet significant clonal growth at metastatic sites as determined by this novel method.

Amino Acid Substitution↗
PubMed1994

[Application of synthetic 27 oligopeptide of HDV antigen for detecting serum anti-HD in HBV infected subjects in Chongqing].

A synthetic HDAg 27 peptide which was selected and designed by the authors and synthesised by Shanghai Institute of Biochemistry, Chinese Academy of Science was used with ELISA method to detect serum anti HD in HBV infected subjects in Chongqing. Anti HD was positive in one of 300 blood donors and was negative in all of 113 cases of hepatitis A and 58 cases of hepatitis non-B. Anti HD was positive in 106 out of 882 cases with positive HBV marker (12.02%), among which anti HD was positive in 3.17% (13/410) of HBsAg carrier, 14.4% (11/76) of acute hepatitis, 7.6% (1/13) of chronic persistent hepatitis, 17.68% (22/121) of chronic active hepatitis, 19.77% (17/86) of severe hepatitis, 29.49% (23/78) of liver cancer and 19.39% (19/98) of primary hepatic cancer. These results coincided with those of previous reports. The coincidence rate was 94.9% (74/78) when compared with Abbott EIA kit. When the natural HDAg was used to compete anti HD in four anti HD positive and two anti HD negative serum specimens, anti HD was negative in all specimens. It is shown that the HDAg 27 peptide has natural HDAg activity capable of being recognized by natural anti HD and is a new diagnostic agent being more simple, save, stable and reliable.

Antibodies, Viral↗
PubMed1990

A new variant of the Es-4 locus in the rat.

A new variant of kidney esterase in the DK/Nac rat strain is reported. The new esterase was tentatively named ES-4C determined by a third allele of the Es-4 locus of Linkage Group V (LGV). Strain distribution was surveyed using 17 inbred strains, but no strain except for the DK/Nac strain possessed the ES-4C type. Although we surveyed outbred stocks (Jcl: Wistar and Jcl: SD) we could not find rats carrying the ES-4C type. Genetic analysis of the ES-4C type was carried out using mating experiments between DK/Nac and BUF/Nac (ES-4B). The results indicated that the new variant was controlled by the Es-4 locus and it was named the Es-4c allele.

Alleles↗
PubMed1990

[The differentiation of human gastric adenocarcinoma cell line MGc80-3 induced by dibutyryl cAMP in vitro].

For providing some experimental basis in establishing malignant phenotypic reversed indexes of gastric carcinoma cells, human gastric adenocarcinoma cell line MGc-80-3 was induced by dBcAMP in vitro to appraise the effect of gastric carcinoma cell differentiation by chemical inducers. Under light microscope, MGc 80-3 cells, after treated with 1 mM dBcAMP, tended to be flat and disperse, and their volume gradually enlarged, with their nucleus relatively smaller and their shape rather regular. Morphological changes, became like normal differentiated epithelial cells, were observed. The cells attached firmly, grew slowly, their growth curve showed inhibitory rate amounted to 52.87%, and cellular division exponent displayed their peak value 1.5 times less than that of MGc 80-3 cells. It was clear that dBcAMP could effectively inhibit the multiplication activity of MGc-80-3 cells. In the cells after dBcAMP treatment, remarkable changes of cell surface charges was indicated by cell electrophoresis, the ratio dropped to 3.043 from 3.988, and their retardant ratio reached up to 31.2%. cAMP content in cells after this treatment, detected by cAMP and cGMP radioimmunoassay, was enhanced by 2.42 times; and cAMP/cGMP ratio, by 1.73 times. Thus, cAMP level within MGc 80-3 cells was raised obviously by dBcAMP. Heterotransplantation experiments showed that tumoriferous rate of MGc 80-3 cells (transplanted subcutaneously to BABL/c mice) amounted to 100%, and that of the cells after this treatment was only 5.6%. Their tumorigenic ability was extremely reduced. These results fully confirmed that dBcAMP was able to change MGc 80-3 cell's malignant phenotypic characteristics and produce a reversed alteration; thus, it has a remarkable inductive effect in differentiating gastric carcinoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1989

Mapping of the Es-4 locus and linear order of esterase genes (linkage group V; LGV) in the rat.

There are three different linear orders of esterase loci of linkage group V (LGV) in the rat (Rattus norvegicus). The first is Es-2-Es-3-Es-1, the second Es-3-(Es-2,Es-4)-Es-1, and the third Es-3-Es-2-Es-1-Es-4. We carried out mating experiments to define the order clearly. Linkage analyses of the four esterase loci, Es-1, Es-2, Es-3, and Es-4, were carried out using two inbred strains carrying different alleles at the four loci. Six locus combinations examined in this study were as follows: Es-1-Es-2, Es-1-Es-3, Es-1-Es-4, Es-2-Es-3, Es-2-Es-4, and Es-3-Es-4. The recombination frequencies of each combination were 6.3, 6.3, 6.3, 5.2, 1.8, and 3.4%, respectively. The first recombination between Es-2 and Es-4 was observed. We propose that the esterase loci of LGV be classified into three clusters according to distances between the loci. The linear order of the four loci is shown to be as follows: [Es-3] (cluster II)-3.4 +/- 2.4%-[Es-4-1.8 +/- 1.7%-Es-2] (cluster III)-6.3 +/- 6.1%-[Es-1] (cluster I).

Animals↗
PubMed1989

[Changes of Golgi complex during the induced differentiation of human gastric adenocarcinoma cells in vitro].

Golgi complex is a central link related to each kind of organella in cellular metabolic process, its morphological changes are often concerned with the cell differentiation and functional state. The Golgi complexes in tumour cells have the characteristics of poor development and non-typical structure, and closely related to their pathological differential degree. For this reason, having based on appraising the differential effect of human gastric adenocarcinoma cell line MGc 80-3 induced by dBcAMP in vitro, we had made a systematic observation on the changes of Golgi complex during the malignant phenotypical reversion of MGc 80-3 cells, in order to inquire into the relationship between the structural and functional changes of Golgi complex and the malignant phenotypic reversion of cancer cells. It was revealed by ultrathin sectioning and freeze-etching electron microscopy that, in MGc 80-3 cells, there were a few Golgi complexes, their volume was small, the amounts of saccule were few, they arranged irregularly, expanded and inflated, and the intramembranous particles on saccule were rare and not well-distributed. It displayed a non-developmental and non-typical structural state of Golgi complex. But after induced treatment with dBcAMP, the Golgi complexes had grown in number and distributed concentrated, , their volume enlarged, the saccules increased and arranged regularly, and the intermembranous particles on saccules were plentiful and well-distributed. They had restored a well-developed and typical structure of Golgi complex similar to that of the primary culture cell of human normal gastric mucous membrane. It showed that Golgi complex had further changed into a quite developed state during the induced differentiation. This alteration not only inhibited the malignant secretory activity of gastric carcinoma cells but also played a certain regulative role in the changes of the surface components of cancer cells. The structural and functional changes of Golgi complex were considered to be an important expression in the malignant phenotypical reversion of cancer cells, it had an important influence on the differentiation of cancer cells from malignant to normal direction.

Adenocarcinoma↗
PubMed1989

[Peripheral T-lymphocyte subsets changes in patients with endocrine and metabolic diseases].

In this study the authors utilized the OKT monoclonal anti-human T lymphocyte antibodies to determine the normal level of T lymphocyte subsets in the peripheral blood of 30 healthy volunteers, 36 patients with Graves' disease (GD), 4 with hypothyroidism and 30 with diabetes mellitus (DM). It is shown that OKT+3, OKT+4 OKT+8 and OKT+4/OKT+8 ratio of T-lymphocyte subsets in the peripheral blood of 30 healthy volunteers were 72.4 +/- 5.1%, 38.9 +/- 5.2%, 26.8 +/- 4.3% and 1.5 +/- 0.3. In 36 patients with GD OKT+3 was 67.6 +/- 5.8%, OKT+4 was 33.8 +/- 6.6% and OKT+8 was 17.9 +/- 6.1%. These were all significantly lower than those of normal controls (P less than 0.001). OKT+4/OKT+8 ratio was 2.1 +/- 0.6, which was significantly higher (P less than 0.001). The value of OKT+4 and OKT+8 in 10 patients with GD after treatment were markedly elevated. However, the ratio of OKT+4/OKT+8 was significantly decreased (P less than 0.05). OKT+3 of 4 cases of hypothyroidism was 69.7 +/- 3.35%, being similar to that of normal controls (P greater than 0.2). OKT+4 and OKT+8 were 31.73 +/- 4.99% and 18 +/- 2.94% respectively, both of which being markedly decreased (P less than 0.01). The ratio of OKT+4/OKT+8 was 1.97 +/- 0.22, being not significantly elevated (P greater than 0.05). OKT+3, OKT+4 and OKT+8 of 23 cases with DM were 68.8 +/- 7.2% (P less than 0.05), 33 +/- 8.1% (P less than 0.005), and 21.2 +/- 6.5% (P less than 0.001) respectively. All of these were significantly decreased. The ratio of OKT+4/OKT+8 was 1.6 +/- 0.5, being not significantly changed.

Adolescent↗