Biomedical subjects
Publications and source records attributed to Z Yan.
During skeletal muscle adaptation to altered functional demands, quiescent satellite cells re-enter the cell cycle and subsequently differentiate into postmitotic myofibers. This process has fundamental importance for adaptation to exercise because the nuclei from satellite cells not only maintain a constant nuclear/cytoplasmic ratio, but also perhaps alter gene expression.
OBJECTIVE: To investigate the influence of the endothelin (ET) and the nitric oxide (NO) on the microcirculation of a super-thinned skin flap. METHODS: With pig, a super-thinned skin flap, only including subdermal vascular networks, was raised and sutured back on its bed on one flank of each pig, and on the other flank a traditional skin flap was also formed for the controlled group. A laser Doppler Flowmeter was used for evaluation of the blood circulation before and after the operation. The endothelin and the nitric oxide of the flap were examined after certain times of the operation. Furthermore, the necrosis of each flap was decided 7 days after the operation. RESULTS: The ET and NO were significantly increasing after 1 hour of the operation in both of the groups (the peak value of ET at 6 hours and NO at 3 hours after the operation). However, the ET in the super-thinned flap group was significantly lower at 1, 3, 6 hours after the operation, compared with the centrolled group (P < 0.05), but the NO measured meantime was significantly higher than the control (P < 0.05). The blood flow of the super-thinned flap was significantly higher than the control flap separately at 1, 3, 6 hours after the operation (P < 0.01). The survival of the super-thinned flap increased about 35% more than the control. There was a negative correlation existed between the ET and the blood flow, as well as a positive correlation between the NO and the blood flow. CONCLUSION: This study has indicated that the changes of the ET and NO in the flaps, especially in the super-thinned flap, have strongly correlated with their microcirculation. The highter survival rate of the super-thinned flap might owes to the mechanism which the ET in the flap produces less while the NO more, Compared with the traditional skin flap.
The insect community and its diversity in mangrove forest at Yingluo Bay of Guangxi were studied in 1995-1996. The results show that there were 195 insect species in the mangrove area, dominated by Crematogaster rogenhoferi, Camponotus tokioensis and Dichocrocris chorophanta. The diversity of insect community was higher in the inside beach than in the middle and outside beaches. Tides and windstorms were the important factors that decided the community composition levels. The principal component affecting the diversity was the species evenness in the inside, middle and outside beaches.
OBJECTIVE: To analyze the morphological characteristics of oocyte, sperm and blastomere-stage embryo and correlate with intracytoplasmic sperm injection (ICSI) embryo score. METHODS: ICSIs were done in M II oocytes harvested after superovulation with long-protocol gonadotropin releasing homone agonist. Various morphological characteristics of oocyte, sperm and blastomere-stage embryo were identified and correlated with the embryo score. RESULTS: Forty-three ICSI cycles were completed. Twelve out of 31 male factor infertile couples and 2 out of 12 with fertilization failure during previous standard in vitro fertilization-embryo transfer cycles achieved clinical pregnancy, resulting in a pregnancy rate of 38.7% and 16.7% per transfer respectively. Severe teratospermia and abnormal cytoplasm of the oocytes, such as cytoplasmic central dark granulas, inclusions, had significantly low embryo score (P < 0.01). The size of perivitelline space had no influence on the result. The oocytes without oolemma elasticity during ICSI process had a lower oocyte survival rate compared with those with oolemma elasticity (P < 0.01). The clinical pregnancy rate per transfer between transferred embryo with average score higher and lower than 3 was significantly different (52% vs 10%, P < 0.001). CONCLUSION: Some morphological characteristics of gamates correlate with the embryo quality and clinical pregnancy rate. They can be used to assess and improve the clinical management during ICSI.
OBJECTIVE: To determine whether genetic factors may work in concert with autoimmune factors in the pathogenesis of Guillain-Barre syndrome (GBS). METHODS: We determined the differences in the distribution of HLA alleles between GBS patients and normal controls. HLA-DQA, -DQB and -DRB alleles were typed by the sequence specific primer polymerase chain reaction (PCR-SSP) methods in 47 GBS, 7 patients with Campylobacter jejuni (CJ) enteritis and 50 normal controls. RESULTS: There were no differences in the frequency of HLA-DQA, -DQB and -DRB among GBS group, CJ group, normal controls and GBS subgroups with respect to recent CJ infection, GM1 IgG and GM1 IgM antibodies (P > 0.05). There was an increasing tendency of DQA1 * 0301 (P = 0.056, RR = 2.991) in the subgroup with GM1 IgG antibodies and DQA1 * 0302 (P = 0.087, RR = 3.587) in the subgroup with recent CJ infection. No difference was found among GBS, CJ enteritis patients and normal controls. CONCLUSIONS: The increasing tendency of the two alleles suggests that there may be some relation between genetic factors and immunological factors, but a definite conclusion waits for more cases.
OBJECTIVE: To review the experience with partial sympathectomy for treating palmar hyperhidrosis with VATS. METHODS: Between July 1995 and June 1999, 50 patients with palmar hyperhidrosis (26 males and 24 females, mean age 26.7 years) were operated. The major symptom was excessive sweating of hands, feet, and axcillaries, sometimes in drops. Thoracoscopy was performed under general anesthesia with a standard single-lumen endotracheal intubation with the patient in a semi-sitting position and arms stretched at 90 degrees. The approach through two small ports on the chest wall was done using VATS. As the lung was depressed by CO(2) insufflation in a low pressure, an excellent view of the upper mediastinum was obtained. Ganglia T(2) through T(4), sometimes T(5) were resected with a electrocautery probe. Bilateral procedures were completed in the same position. RESULTS: All patients after operation became dry immediately after sympathetic denervation with a few minor complications. Occasional side effect was moderate compensatory sweating of the trunk. One case had recurrence but sweating was much less than before operation. CONCLUSIONS: Because of excellent view of the upper mediastinum for sympathetic denervation of the hand and axcillaryies, the effect of partial sympathectomy for palmar hyperhidrosis is satisfactory and permanent.
OBJECTIVE: To evaluate the frequency and nature of LKB1 gene germline mutations in 4 large Chinese Peutz-Jeghers syndrome pedigrees. METHODS: Four Chinese Peutz-Jeghers syndrome pedigrees were investigated. Two patients and 1 normal adult from each pedigree were selected, and genomic DNA from peripheral blood was extracted. The 9 exons of LKB1 gene were amplified by PCR. The products were tested by SSCP and abnormally shifted bands were sequenced. If there was no positive finding in any pedigree, the entire exons were sequenced. RESULTS: The same 842 C deletion of LKB1 gene frame-shift mutations was found in 2 pedigrees, which resulted in truncated protein. No exon variant was found in the left 2 pedigrees. CONCLUSIONS: LKB1 gene germline mutation is an important molecular pathogen of Peutz-Jeghers syndrome. 842 C deletion is a possible mutation hotspot and might be a common-ancestor mutation characteristic of Chinese.
cFn synthesized by FBs around the wound was detected by immunochemistry in vitro. Using the method of ELISA, The concentration of cFn in the culture media was observed. The concentration of cFn had no change within 30 minutes after injury, but started to increase after 1 hour of the injury and kept this trend within next five hours after injury. By static analysis, it can be obtained that the concentration of cFn in culture media is time-dependent after injury.
By comparing the purification results of radial-flow chromatography with conventional chromatography, a new purification process of follicle-stimulating hormone (FSH) from crude sample of human menopausal gonadotrophin has been developed. The results showed that the specific activity, activity recovery, and purification factor of FSH purified by radial-flow chromatography were higher than those by conventional chromatography in large scale. The specific activity of FSH purified was 180 IU/mg protein, activity recovery 56%, purification factor 150. The purified product meets the quality requirement of the Standard of Chinese Pharmacopoeia.
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OBJECTIVE: To explore whether the immune response of the inner ear could induce heat shock protein (hsp) 70 in guinea pig cochlea. METHODS: A model of autoimmune inner ear disease (AIED) was established by systemically immunizing the guinea pig with the homologous crude inner ear antigen (CIEAg). The immunized cochleae and normal control cochleae were examined for the expression of hsp70 with techniques of immunohistochemistry and in situ hybridization. RESULTS: In the control animals, the expression of the hsp70-like protein appeared only in the spiral ganglion, whereas in the cochleae with CIEAg immunization, strong expression of the hsp70-like protein and its mRNA appeared in the spiral ganglion as well as in the stria vascularis and the spiral ligament. The hearing thresholds were significantly increased in 10 out of 28 cochleae (35.7%) with CIEAg immunization. CONCLUSION: The results suggest that the immune response of the inner ear can induce the expression of hsp70 in the guinea pig cochlea.
By means of artificial neural network and back-propagation train algorithm, the three-component metal coordinate compounds of PAR-Zn, Cu, Co were determined simultaneously, in which the spectra overlapped. In 580-440 nm, the absorbance(A) at 14 wavelength were taken as character parameter of artificial neural network, and samples were arranged by method of uniformity design. The mean recovery of Zn, Cu, Co were 95.22%, 95.98% and 100.5%. The experiment results show that the determination is accurate, and the method has good performance.
An experimental study was conducted to evaluate the effectiveness of the various components of Athabasca bitumen in stabilizing water-in-diluted-bitumen emulsions. The solvent used to dilute the very viscous bitumen was a mixture of 50:50 by volume of hexane and toluene. The various bitumen components studied were asphaltenes, deasphalted bitumen, and fine solids. It was found that asphaltenes and fine solids were the main stabilizers of the water-in-diluted-bitumen emulsions. Individually, the two components can stabilize water-in-diluted-bitumen emulsions. However, when both are present the capacity of the diluted bitumen to stabilize water emulsions is greatest. Emulsion stabilization tests indicated that whole bitumen had less capacity to stabilize water emulsions than asphaltenes and solids. This would indicate that the presence of the small molecules within the whole bitumen tends to lower the emulsion stability. Deasphalted bitumen acts as a poor emulsion stabilizer. Although deasphalted bitumen led to the least emulsion stabilization capacity, interfacial tension measurements showed that diluted deasphalted bitumen gave a greater decrease in the interfacial tension of water with diluent. Copyright 1999 Academic Press.
The physiological state of the cell is controlled by signal transduction mechanisms which regulate the balance between protein kinase and protein phosphatase activities. Here we report that a single protein can, depending on which particular amino-acid residue is phosphorylated, function either as a kinase or phosphatase inhibitor. DARPP-32 (dopamine and cyclic AMP-regulated phospho-protein, relative molecular mass 32,000) is converted into an inhibitor of protein phosphatase 1 when it is phosphorylated by protein kinase A (PKA) at threonine 34. We find that DARPP-32 is converted into an inhibitor of PKA when phosphorylated at threonine 75 by cyclin-dependent kinase 5 (Cdk5). Cdk5 phosphorylates DARPP-32 in vitro and in intact brain cells. Phospho-Thr 75 DARPP-32 inhibits PKA in vitro by a competitive mechanism. Decreasing phospho-Thr 75 DARPP-32 in striatal slices, either by a Cdk5-specific inhibitor or by using genetically altered mice, results in increased dopamine-induced phosphorylation of PKA substrates and augmented peak voltage-gated calcium currents. Thus DARPP-32 is a bifunctional signal transduction molecule which, by distinct mechanisms, controls a serine/threonine kinase and a serine/threonine phosphatase.
Dopamine, by activating D(1)- and D(2)-class receptors, plays a significant role in regulating gene expression. Although much is known about D(1) receptor-regulated gene expression, there has been far less information on gene regulation mediated by D(2) receptors. In this study, we show that D(2) receptors can activate the mitogen-activated protein kinase (MAPK) and the cAMP response element-binding protein (CREB) in neurons. Treatment of brain slices with the D(2) receptor agonist quinpirole induced rapid phosphorylation of MAPK and CREB. The neuroleptic drug eticlopride, a highly selective D(2) receptor antagonist, blocked the quinpirole-induced phosphorylation of MAPK and CREB. D(2) receptor-induced MAPK phosphorylation depended on intracellular Ca(2+) elevation, protein kinase C activation, and MAPK kinase activation, but not on the protein tyrosine kinase Pyk2, even though quinpirole stimulated Pyk2 phosphorylation. D(2) receptor-induced CREB phosphorylation was mediated by activation of protein kinase C and Ca(2+)/calmodulin-dependent protein kinase, but not MAPK. The dopamine and cAMP-regulated phosphoprotein DARPP-32 also was required for the regulation of MAPK and CREB phosphorylation by D(2) receptors. Our results suggest that MAPK and CREB signaling cascades are involved in the regulation of gene expression and other long-term effects of D(2) receptor activation.
Our previous studies have shown that the His tag cleaved from fusion proteins contained two distinct components P1 and P2. P1 has been identified to be a His-tagged peptide of G-H-H-H-H-H-H-H-H-H-H-S-S-G-H-I-E-G-R resulted from initiator methionine deletion, and P2 contains an unknown moiety at the second residue glycine of the tag (x-G-H-H-H-H-H-H-H-H-H-H-S-S-G-H-I-E-G-R, x = 178.0 Da). This study aimed to determine the structure of the modification by using a combination of protein isotope labeling and mass spectrometry. His-tagged FKBP was expressed in (15)N and (13)C labeling growth media respectively. Isotopic labeled His-tagged proteins ((15)N-His-FKBP and (13)C-His-FKBP) were isolated by affinity chromatography and subjected to Xa digestions to release the labeled His tag. Subsequent analyses of the released His tag by MALDI-TOF-MS indicated a mass difference of 178.0 +/- 0.2 Da, between the two (15)N-labeled peptides P1 and P2, suggesting that the modification moiety contained no nitrogen. A mass difference of 184.0 +/- 0.2 Da was observed on MALDI between (13)C-labeled peptide P1 and P2, indicating six carbons in the modification group. Also, comparing the mass shift on MALDI spectra of P1 and P2 after hydrogen/deuterium exchange revealed that the modification moiety had five hydroxyl groups. It was concluded that the modification was a gluconic acid derivative attached to the N-terminus of His-tagged proteins expressed in bacteria. The proposed structure was further confirmed by MALDI analysis of periodate oxidation products of His-tagged peptides.
The apparent molar volumes V(2,phi) have been determined for glycine, DL-alpha-alanine, DL-alpha-amino-n-butyric acid, DL-valine and DL-leucine in aqueous solutions of 0.5, 1.0, 1.5 and 2.0 mol kg(-1) sodium acetate by density measurements at 308.15 K. These data have been used to derive the infinite dilution apparent molar volumes V(0)(2,phi) for the amino acids in aqueous sodium acetate solutions and the standard volumes of transfer, Delta(t)V(0), of the amino acids from water to aqueous sodium acetate solutions. It has been observed that both V(0)(2,phi) and Delta(t)V(0) vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids. These linear correlations have been utilized to estimate the contributions of the charged end groups (NH(3)(+), COO(-)), CH(2) group and other alkyl chains of the amino acids to V(0)(2,phi) and Delta(t)V(0). The results show that V(0)(2,phi) values for (NH(3)(+), COO(-)) groups increase with sodium acetate concentration, and those for CH(2) are almost constant over the studied sodium acetate concentration range. The transfer volume increases and the hydration number of the amino acids decreases with increasing electrolyte concentrations. These facts indicate that strong interactions occur between the ions of sodium acetate and the charged centers of the amino acids. The volumetric interaction parameters of the amino acids with sodium acetate were calculated in water. The pair interaction parameters are found to be positive and decreased with increasing alkyl chain length of the amino acids, suggesting that sodium acetate has a stronger dehydration effect on amino acids which have longer hydrophobic alkyl chains. These phenomena are discussed by means of the co-sphere overlap model.