Biomedical subjects
Publications and source records attributed to X Yin.
Icariin in Chinese traditional medicine was determined by an accurate and simple capillary zone electrophoresis method which used 30 mmol/L of borate solution containing 10% of acetonitrile as running buffer and needed no pretreatment.
Facial bone, as the frame to support maxillofacial region and with several sinuses and cavities, is structurally complicated and the maxillofacial tumors, benign or malignant, in this region usually grows into the deep tissues, sinus-cavities and orbit and destroys the bone. In this study, the maxillofacial tumors were subjected to a mimic operation on a computer following CT scanning and 3-dimensional reconstruction. The data similar to those of real operation were obtained, which could be used for developing operative plans. As compared with data on the basis of conditions in the real operation, computerized mimic operation reflected the real conditions during operation. Computerized mimic operation is valuable for the preoperative planning and the prediction of probable intraoperative events.
Rapid detection and quantitative assessment of specific microbial species in environmental samples is desirable for monitoring changes in ecosystems and for tracking natural or introduced microbial species during bioremediation of contaminated sites. In the interests of developing rapid tests for hydrocarbon-degrading bacteria, species-specific PCR primer sets have been developed for Pseudomonas aeruginosa, Stentrophomonas (Xanthomonas) maltophilia, and Serratia marsescens. Highly variable regions of the 16S rRNA gene were used to design these primer sets. The amplification products of these primer sets have been verified and validated with hemi-nested PCR and with ligase chain reaction (LCR) techniques, and have been applied to the analyses of environmental water samples. These species-specific primer sets were also chosen to amplify in conjunction with a universal set of PCR primers chosen from highly conserved neighboring sequences in the same gene. These multiplex or competitive PCR procedures enable testing with an internal marker and/or the quantitative estimation of the relative proportion of the microbial community that any one of these species occupies. In addition, this universal PCR primer set amplified the same size amplicon from a wide spectrum of procaryotic and eucaryotic organisms and may have potential in earth biota analyses.
Background and induced germline mutagenesis and other genotoxicity studies have been hampered by the lack of a sufficiently sensitive technique for detecting mutations in a small cluster of cells or a single cell in a tissue sample composed of millions of cells. The most frequent type of genetic alteration is intragenic. The vast majority of oncogenic mutations in human and mammalian cancer involves only single base substitutions. We have developed universally applicable techniques that not only provide the necessary sensitivity and specificity for site specific mutagenesis studies, but also identify the point mutation. The exponential amplification procedures of polymerase chain reaction (PCR) and ligase chain reaction (LCR) have been combined with restriction endonuclease (RE) digestion to enable the selective enrichment and detection of single base substitution mutations in human oncogenic loci at a sensitivity of one mutant in more than 10(7) wild type alleles. These PCR/RE/LCR procedures have been successfully designed and used for codons 12 and 248 of the Ha-ras and p53 genes, respectively, both of which contain a natural MspI restriction endonuclease recognition sequence. These procedures have also been adapted for the detection and identification of mutations in oncogenic loci that do not contain a natural restriction endonuclease recognition sequence. Using PCR techniques, a HphI site was incorporated into the codons 12/13 region of the human N-ras gene, which was then used for the selective enrichment of mutants at this oncogenic locus. These PCR/RE/LCR procedures for base substitution mutations in codon 12 of the N-ras gene were found to have the sensitivity of detection of at least one mutant allele in the presence of the DNA equivalent of 10(6) wild type cells. Only one peripheral blood leukocyte DNA specimen out of nine normal individuals displayed an observable Ha-ras mutation that was present at frequency between 10(-5) and 10(-6). These PCR/RE/LCR techniques for detecting and identifying base substitution mutations are universally applicable to almost any locus or base site within the human or animal genome. With the added advantage of the adjustability of both the amount of DNA (number of genomes) to be tested and the sensitivity (10(-2) to 10(-7)) of the assay selection or enrichment procedures, these PCR/RE/LCR techniques will be useful in addressing a broad range of important questions in mutagenesis and carcinogenesis.
Crop modelling has so far contributed little to the genetic analysis of a quantitative trait. This study illustrates how a simple model for crop phenological development, which assumes that crop development rate is affected by daily effective temperature, can assist the identification of Quantitative Trait Loci (QTLs), using specific leaf area (SLA) in barley as an example. The SLA was measured in a field experiment six times during the growing season of 94 recombinant inbred lines (RILs) derived from a cross between cultivars Prisma and Apex. Of the six measurements, one was conducted at the same physiological age for all RILs (at flowering), four were undertaken at specific chronological days prior to flowering, and the last one was taken at 14 days after flowering. When the measured SLA was directly used as the quantitative trait, one to three QTLs were detected for SLA at each measurement time. The major dwarfing gene denso segregating in the population was found to affect SLA strongly at all measurement times except at flowering. If SLA of the different RILs was corrected for differences in physiological age at the time of measurement, by the use of the crop development model, QTLs were detected for SLA at only three stages. Furthermore, the effect of the denso gene was no longer significant during the preflowering stages. The effect of the denso gene detected in the first instance was therefore the consequence of its direct effect on the duration of the preflowering period. This demonstrates the important role that crop development models can play in QTL analysis of a trait that varies with developmental stage. Potential uses of ecophysiological crop growth models in QTL analysis are briefly discussed.
OBJECTIVE: To investigate portal hemodynamics and its correlation with esophageal variceal bleeding (EVB) in cirrhotics with portal hypertension by using a newly-developed technique, color Doppler velocity profile (CDVP). METHODS: Hemodynamics of portal trunk (PT), right anterior branch (RAB) and splenic vein (SV) were evaluated in 48 cirrhotics with portal hypertension and 35 normal volunteers by CDVP. The parameters included maximum cross-sectional velocity (CS-Vmax), flow volume, congestion index (CI), profile parameter N and pattern of flow curve. Stepwise logistic regression model was employed to determine EVB-relating factors in cirrhotics. RESULTS: CS-Vmax in PT and RAB was significantly lower in cirrhotic group than that of normal group, being 14.91 +/- 3.08 cm/s, 9.44 +/- 2.70 cm/s vs 30.52 +/- 6.75 cm/s, 12.82 +/- 2.69 cm/s, respectively (P < 0.01 for both). Flow volume of PT and SV was significantly higher in cirrhotic group compared with that of normal group, being 25.16 +/- 10.48 ml.min-1.kg-1, 15.83 +/- 9.18 ml.min-1.kg-1 vs 20.43 +/- 5.57 ml.min-1.kg-1, 5.81 +/- 2.04 ml.min-1.kg-1, respectively (P < 0.01 for both). CI of PT, RAB and SV was significantly higher in cirrhotic group than in normal group, being 0.142 +/- 0.0654, 0.105 +/- 0.0496, 0.0884 +/- 0.0431 vs 0.0326 +/- 0.0142, 0.0757 +/- 0.0342, 0.0483 +/- 0.0230, respectively (P < 0.01 for all). In dynamic variation of flow volume over time, RAB and SV in cirrhotic group increasingly presented flat pattern and periodically changed pattern, respectively (P < 0.01 for both). Between cirrhotic subgroups without and with EVB history, there were significant differences in flow volume, CI and N value of SV, splenic size, degree of esophageal varices (EV) and portal hypertensive gastropathy (PHG), and stepwise logistic regression revealed that N value of SV, splenic size, degree of EV and PHG were four independent factors in relation to EVB. EVB scores calculated from the regression equation had a close correlation with EVB. In patients with EVB score > 0, 88.9% of them had EVB, and in those with EVB < 0, 76.9% of them had no history of EVB. CONCLUSION: In cirrhotics with portal hypertension, portal venous system has the features of elevated vascular resistance and hyperdynamics, and the latter mainly results from increased blood flow in SV. EVB score may become a valuable parameter in predicting occurrence of EVB.
OBJECTIVE: To study the relationship between the expression of apoptosis related genes in the tissue of non-small cell lung carcinoma (NSCLC) and clinicopathology in the tumor. METHODS: The expression of bcl-2, bax, Fas and FasL were detected with immunohistochemistry method in 45 cases of NSCLC. RESULTS: 23 (51%) cases of NSCLC were bcl-2 positive, 38 (84%) were bax positive (P < 0.01), and there was no significant correlation between the expression of bcl-2 and bax protein, but a positive relationship was found between the expression of Fas and FasL (P < 0.01). The positive rate of bcl-2 expression decreased in advanced stages of NSCLC(P < 0.05), the bax expression was lower in cases with poor cell differentiation (P < 0.05), and the FasL expression was higher in adenocarcinoma (P < 0.01). The simultaneous expression of bcl-2 and bax protein was closely correlated with TNM stages (P < 0.05), the differences of bcl-2 protein expression alone in NSCLC with cell differentiation were statistically significant (P = 0.033). CONCLUSIONS: Both bcl-2, bax, Fas and FasL may involve in the regulation of apoptosis and may play an important role in the occurrence and progression of NSCLC.
OBJECTIVE: To investigate the efficacy of internal radiation of (32)P-glass microspheres ((32)P-GMS) in unresected hepatocellular carcinoma (HCC) via subcutaneous arterial port. METHODS: Hepatic arterial (99)technetium-macroaggregate albumin ((99)Tc-MAA) scanning via subcutaneous arterial port was undertaken to measure lung/liver shunting ratio and tumor/liver ratio. Hepatic arterial infusion of (32)P-GMS was performed in 17 cases of HCC with a dose from 1.11 to 1.30 GBq. Twenty cases of HCC undergoing hepatic arterial chemoembolization (HACE) in the same period served as controls group. RESULTS: There was no treatment-related death in the 17 cases. In 7 of the 17 cases, AFP level and/or tumor size decreased by 50% after treatment, with a response rate of 64.7%. The median survival time was 5.5 months, and the 3-, 6-, 9-, 12-month survival rates were 94.1%, 44.1%, 31.0%, 24.4%, respectively. The therapeutic efficacy was better than that of HACE. The survival time was significantly longer in patients with T/N ratio >or= 2 than in those with T/N < 2 (P < 0.05). CONCLUSIONS: Hepatic arterial infusion of (32)P-GMS is an alternative treatment for unresected HCC.
OBJECTIVE: To explore effects of tantalum and its oxide on the exposed workers. METHODS: Health examination for 113 workers exposed to tantalum and its oxide and a field survey for occupational hygiene in the workplace were carried out. RESULTS: Workplace air concentration of tantalum and its oxide averaged 0.1 - 7.6 mg/m(3). There was no significant difference in prevalence of symptoms and signs and biochemical, pulmonary function, chest X-ray and electrocardiograph examinations between the exposed and control workers. CONCLUSION: No adverse effect of tantalum and its oxide on the exposed workers was found.
OBJECTIVE: To gain a clear idea of the drug Gualoupi and its adulterants. METHOD: Collecting data and spot investigating in 30 provinces, cities and autonomous regions in China. RESULT: Gualoupi used as drug in China consists of 15 species of Trichosanthes, 1 species of Momordica, 1 species of Citrullus and 1 species of Adenia(Passifloraceae). CONCLUSION: The main commodity is the rind of T. kirilowii or T. rosthornii, and the main adulterant is the rind of T. hupehensis.
OBJECTIVE: To make clear the histological characteristics of rinds for eighteen species of Gualou. METHOD: Observing the cross sections and separate divide of the rinds with light microscope. RESULT AND CONCLUSION: Of eighteen rinds of Gualou, each trichome on exocarp, wood fiber and thickness of ring of stone cell are different from one another, this distinction can be used to identify the different rinds of Gualou.
OBJECTIVE: To explore the antiendotoxin effect of extracts from Artemisia annua (AA) and qinghaosu (QHS). METHOD: LPO and SOD in chondriosome, ACP in lysosomes, tumor nicrosis factor-alpha(TNF-alpha) and endotoxin in plasma, and P450 concentration in hepatic microsome of rats were determined. Mortality of endotoxemic mice and histomorphology were observed. RESULT: LPO, ACP, endotoxin, TNF-alpha and P450 content were decreased with AA and QHS. SOD activity was increased with AA and QHS. At the same time, mortality was decreased. Histomorphology of lysosomes and chondriosome of rats were protected from endotoxin. CONCLUSION: AA and QHS possess an antiendotoxin effect.
The authors studied the toxicity of P-Dichlorobenzene(P-DCB). The results showed that the toxicity of P-DCB was low. It has no accumulation (K > 5), no eye irritation and no skin sensitization effects. But light skin irritation effect was observed. In sub-acute inhalate exposure, damage on the function of liver and kidney was not observed. Genotoxic tests showed that tests in s. typhimurium strains TA98 and TA100 did not show any mutagenic potential. In Chinese hamster lung fibroblast CHL cell test system, it did not cause chromosomal aberrations.
By immunizing prion knockout mice (Prnp-/-) with recombinant murine prion protein (PrPc), we obtained a panel of mAbs specific for murine PrPc. These mAbs can be applied to immunoblotting, cell surface immunofluorescent staining, and immunohistochemistry at light and electron microscopy. These mAbs recognize both the normal (PrPc) and protease-resistant (PrPres) isoforms of PrP. Some mAbs are species restricted, while others react with PrP from a broad range of mammals including mice, humans, monkeys, cows, sheep, squirrels, and hamsters. Moreover, some of the mAbs selectively recognize different PrP glycoforms as well as the metabolic fragments of PrPc. These newly generated PrPc antibodies will help to explore the biology of PrPc and to establish the diagnosis of prion diseases in both humans and animals.
Cardiac oxidative injury is a major limiting factor for clinical application of Adriamycin (ADR) in cancer chemotherapy. ADR depresses some antioxidant systems, thereby further enhancing the cardiotoxicity. Previous studies have shown that ADR inhibits the overall synthesis of DNA, RNA, and protein. It was presumed that the depressed antioxidant activity resulted from the inhibited gene expression. However, there were no experimental data to demonstrate the relationship between the change in antioxidant activities and that in their gene expression. Therefore, the present study was undertaken to examine the effects of ADR on the activities and mRNA abundances of antioxidants in mouse heart. FVB mice (7 weeks old) were treated with ADR (15 mg/kg) by a single i.p. injection. Four days after the treatment, cardiac antioxidant activities and mRNA abundances were measured. The results showed that ADR increased the levels of mRNAs for Cu,Zn-superoxide dismutase (Cu,Zn-SOD), catalase, glutathione peroxidase (GSHpx), and gamma-glutamylcysteine synthetase (gamma-GCS). On the other hand, ADR increased the activities of catalase and gamma-GCS, and slightly decreased total glutathione concentrations in the heart. Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, and glutathione peroxidase activities were not changed significantly. In addition, ADR increased both mRNA and protein levels of metallothionein in the heart. The data demonstrate that up-regulation of antioxidant gene expression occurred in response to ADR in the mouse heart, although the antioxidant activities were not all increased.
Myelination increases neuronal conduction velocity through its insulating properties and an unidentified extrinsic effect that increases axonal caliber. Although it is well established that demyelination can cause axonal atrophy, the myelin molecule that regulates axonal caliber is not known. Loss of the structural proteins of compact peripheral nervous system (PNS) myelin, P0 protein, and myelin basic protein does not lead to axonal atrophy. This study demonstrates that mice with a null mutation of the myelin-associated glycoprotein (MAG) gene have a chronic atrophy of myelinated PNS axons that results in paranodal myelin tomaculi and axonal degeneration. Absence of MAG was correlated with reduced axonal calibers, decreased neurofilament spacing, and reduced neurofilament phosphorylation. Because axonal atrophy and degeneration in MAG-deficient mice occur in the absence of inflammation, hypomyelination, significant demyelination-remyelination, or gain of function mutations, these data support a functional role for MAG in modulating the maturation and viability of myelinated axons.
C-myc, a member of the basic helix-loop-helix-leucine zipper (bHLH-ZIP) protein family activates target genes in heterodimeric association with another bHLH-ZIP protein, Max. Max readily homodimerizes, competes with C-myc-Max heterodimers, and represses transcription. Four additional bHLH-ZIP proteins, Mad1, Mxi1, Mad3 and Mad4, heterodimerize with Max and also repress transcription of c-myc-responsive genes. We employed a yeast two-hybid approach to identify proteins which interact with Mxi. We identified a novel ZIP-containing protein, Mmip1 (Mad member-interacting protein 1) that strongly dimerizes with all four Mad members, but not with c-myc, Max, or with unrelated HLH proteins. The Mmip1-Mxi association is mediated by the ZIP domain of each polypeptide and is as strong or stronger than the associations between c-myc and Max or Max and Mxi1. In vitro, Mmip1 can inhibit DNA binding by Max-Mad heterodimers and, in vivo, can reverse the suppressive effects of Mad proteins on c-myc functions. Mmipl is found in a variety of cells types, is induced by serum stimulation, and can be co-immunoprecipitated from fibroblasts in association with Mxi1. By interfering with the dimerization between Max and Mad family member proteins, Mmip1 can indirectly up-regulate the transcriptional activity of c-myc and suppress the antiproliferative actions of Mad proteins.
We have examined the induction of the enzymes of the heme biosynthetic pathway during erythroid differentiation of mouse embryonic stem (ES) cells. Following transfer to appropriate medium all of the pathway enzymes are induced within three days. Unlike differentiating mouse erythroleukemia cells (Lake-Bullock, H. and Dailey, H.A. Mol Cell Biol 13:7122-7132, 1993), all of the enzymes appear to be induced simultaneously and not sequentially in differentiating ES cells. The role of erythroid 5-aminolevulinate synthase (ALAS-2) in this differentiation process was examined by disruption of the ALAS-2 gene. The targeting vector used for disruption replaced all of exons 4 to 6 with a selectable neomycin resistance gene. The resulting genetically modified (ALAS-2 knockout) cells, as well as normal ES cells were used to study induction of heme biosynthesis. Following 10 days of culture in methylcellulose media significant morphological differences between the embryoid bodies (EBs) of the two cell lines were observed. ES cells exhibited morphology of typical EBs with a dark field (blood island) in the center, while ALAS-2 knockout ES cells developed very poorly both in size and shape. At 8 days of differentiation, only 3% of all EBs contained visible erythropoietic cells (i.e., stained positively for hemoglobin) in the ALAS-2 knockout cell line, compared with 50% in ES cells. Most of the genes in the heme synthetic pathway were expressed to a stable level within 3 to 6 days after induction in normal ES cells, while the ALAS-2 knockout cell line failed to significantly increase the level of expression of these genes. Fetal beta-globin mRNA was not detectable in the differentiating ALAS-2 knockout cells, whereas mRNA for this gene was detected in normal ES cells within 3 days of differentiation. These results suggest that ALAS-2 is necessary for ES cell erythroid differentiation and that there is an interrelationship between heme and globin synthesis in differentiating ES cells.