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Biomedical subjects

M Qin

Publications and source records attributed to M Qin.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Bone mineral analysis of whole body in 292 normal subjects assessed by dual X-ray absorptiometry].

OBJECTIVE: To understand whole body bone mineral changes in normal subjects. METHODS: Bone mineral was measured by dual X-ray absorptiometry (DXA) in 292 normal subjects aged 10-79, including 152 females and 140 males. They were divided into age-groups by decade. RESULTS: In males, peak value ages of total bone mineral content(TBMC), total bone mineral density(TBMD), anteroposterior spine BMD(L2-4 BMD) were in the 30-39, 20-39, 20-29 age-groups respectively. In females, they were all in the 30-39 age-group. Peak values of TBMC, TBMD, L2-4BMD were higher in males than those in females. Loss of bone mineral for females was more pronounced than that for males. There was a tendency of increased BMD among the 70-79 age-group for males. Loss of L2-4 BMD was more pronounced than TBMD. CONCLUSIONS: This study provides the normal bone mineral data of whole body for males and females, and the characteristic of changes.

Absorptiometry, Photon↗
PubMed1999

Comparison of bone mass in forearm, lumbar vertebra and hip by single and/or dual energy X-ray absorptiometry.

OBJECTIVE: Bone mineral density (BMD) was measured in normal Chinese women with single X-ray absorptiometry (SXA) and dual energy X-ray absorptiometry (DEXA). These two methods were compared to evaluate the sensitivity in reflecting bone loss. METHODS: Measurements were performed in 300 women aged 20 to approximately 79 (5 for each age). The 8mm distal, 1/4 distal, ultra distal site of the nondominant forearm were measured with SXA; the AP spine (L2-4), right femoral neck (Neck), Ward's triangle (Ward) and trochantor (Troch) were measured with DEXA. Ten women had 5 repeated measurements to evaluate the reproducibility of the equipments. RESULTS: The BMD peak for Neck and Ward was found between age 20 to approximately 29, for ultra distal and L2-4 at age 30 to approximately 39, for 8mm distal, 1/4 distal and Troch at age 40 to approximately 49. After reaching the peak values, BMD at all sites decreased with increasing age. The highest rate of yearly loss of BMD was at 8mm distal. Results of measurement showed significant correlation between SXA and DEXA. Comparing with premenopausal women, the bone loss rate in postmenopausal women was faster and highest up to 11 to approximately 15 years and the highest rate was at the Ward. CONCLUSION: The present study gives the normal values of BMD at seven sites for normal Chinese women. The ages of BMD peak were different at seven sites. The yearly loss of BMD was highest at 8mm distal, it seemed to be the sensitive region for bone loss with age. The postmenopausal women had highly significantly loss bone mass than the premenopausal women. Comparing with premenopause, postmenopause BMD for Ward's triangle with DEXA seemed to be most sensitive to the effect of menopause.

Absorptiometry, Photon↗
PubMed1998

[Anatomy of Aconitum finetianum Hand.-Mazz].

The primary xylem of plump taproot of Aconitum finetianum is the diarch with xylem in the center. In the action of the secondary structure of the herb, the meristem is first produced in the secondary phloem, then the anomalous cambium is produced in the secondary xylem forms a new and splits into anomalous structure. In the action of anomalous structure of the herb, the meristem in the secondary phloem sinks inwardly from many sites, and forms many rings with the anomalous cambium. One of these rings forms a special endodermis and the protostele turns into the schizogenous stele.

Magnoliopsida↗
PubMed1998

[Implementing a relatively rigorous algorithm of dynamic EIT problem on the modified FEM model].

We deduced a relatively rigorous algorithm of dynamic EIT problem-general inverse algorithm, and implemented it on the computer FEM model. Images which can show the changing of the resistivity(i.e. dynamic resistivity images) were gained. Also we modified the ordinary FEM model according to the characteristic of the EIT problem and implemented the general inverse algorithm on the modified model. The ill-posed condition of the forward matrix based on the modified model was fairly improved. It can be seen from the results that the general inverse algorithm with modified FEM model is an algorithm better than the back-projection algorithm in terms of object locating, image definition, and the ability of dealing with complex object and noise.

Algorithms↗
PubMed1997

Overexpressed phytochrome C has similar photosensory specificity to phytochrome B but a distinctive capacity to enhance primary leaf expansion.

Phytochrome C (phyC) is a low-abundance member of the five-membered phytochrome family of photoreceptors in Arabidopsis. Towards developing an understanding of the photosensory and physiological functions of phyC, transgenic Arabidopsis plants were generated that over-express cDNA-encoded phyC and seedling responses to continuous white, red, or far-red light (Wc, Rc or FRc, respectively) were examined. Transgenic seedlings over-expressing phyC displayed enhanced inhibition of hypocotyl elongation in Rc, but were unchanged in responsiveness to FRc relative to wild-type. These data indicate that phyC has photosensory specificity that is similar to that of phyB and thus distinct from that of phyA. phyC overexpressors with levels only 3 to 4 times the level of endogenous phyC exhibited enhanced primary leaf expansion in Wc. This is in contrast to phyA or phyB overexpressors which respectively have levels that are 500- and 100-fold that of overexpressed phyC but showed no enhancement of primary leaf expansion. Therefore, phyC may have some physiological roles that are different to those of phyA and phyB in the control of seedling responses to light signals.

Apoproteins↗
PubMed1997

[Surgical treatment in pulmonary tuberculosis with sputum long-term Mycobacterium tuberculosis positive].

OBJECTIVE: To evaluate the importance of surgical treatment in pulmonary tuberculosis with sputum long-term Mycobacterium tuberculosis positive. METHOD: Sixty-five patients with pulmonary tuberculosis who failed antituberculosis chemotherapy received lung resection or thoracoplasty. RESULT: Sputum negative conversion was found in sixty-three patients without recurrence during 1-3 year follow-up, while sputum positive conversion was found only in one case during the period of follow-up. Among all the patients, one died of respiratory failure after the operation, three complicated with empyema and recovered from operating again. CONCLUSION: Surgical operation is still important for treating pulmonary tuberculosis patients with sputum long-term Mycobacterium tuberculosis positive.

Adolescent↗
PubMed1997

[Intervention approach and its effect on lowering mortality of ectopic pregnancy in Shanghai].

OBJECTIVE: To explore an effective intervention approach to lower the mortality of ectopic pregnancy. METHODS: We monitored the mortality of ectopic pregnancy during 1987-1995 in Shanghai and experts' audit, focusing on the causes of death from ectopic pregnancy and combining official administration with intervention approach in medical institutions. RESULTS: Misdiagnosis and patient's delay to hospital were the causes of death from ectopic pregnancy. There were 523,299 live births in Shanghai from 1987 to 1989, in which 23 cases died from ectopic pregnancy, with a mortality of 4.40/100,000. After implementing the intervention approach, during 1990-1995, 14 cases of the total 625,206 nancies live birth died from ectopic pregnancy, with a mortality of 2.24/100,000, as compared the two, P < 0.05. Accordingly, ectopic pregnancy as the cause of maternal death dropped from the first leading cause to the fourth. CONCLUSION: Intensive health care education in masses, medical staffs' awareness to ectopic pregnancy, and intervention, early hospitalization, early diagnosis and early therapy can lower the mortality of ectopic pregnancy.

Adult↗
PubMed1996

Expression of variants of the major surface glycoprotein of Pneumocystis carinii.

Previously, we have shown that a multicopy family of related but unique genes encodes the major surface glycoprotein (MSG) of Pneumocystis carinii. To examine whether different members of this gene family are expressed by P. carinii, antisera were prepared against peptides whose sequences were determined from the deduced amino acid sequences of variants of rat-derived MSG. Immunohistochemical staining of serial sections of rat lungs of infected animals showed that at least three variants of MSG were expressed in an individual lobe, that there was a focal expression of these variants within the lung, and that the relative numbers of these foci were different. Indirect immunofluorescent staining of purified P. carinii organisms using these antisera revealed that at least three variants of MSG were present in organisms isolated from an individual rat and that both cysts and trophozoites reacted with each antiserum. A substantial difference in the fraction of organisms reacting with a specific antipeptide antiserum was seen when comparing organisms isolated from rats raised in a single colony over a period of two years as well as organisms isolated at one time point from rats raised in different colonies. This demonstration of antigenic variation in P. carinii supports the hypothesis that P. carinii utilizes such variation for evading host defense mechanisms.

Amino Acid Sequence↗
PubMed1996

[Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography].

Spinal BMD was measured by QCT in 445 normal individuals aged 10-80 including 190 males and 255 females, which were divided into age-groups by every ten years. Statistic results showed that peak bone mass reached at 10-19 age-group for both male and female and that BMD assessed by QCT in females was not lower than that in males and BMD declined with increasing age. In females, BMD results in this study were different from those in USA. An acceleration bone loss was predominantly shown in the period after 40-49 age group. Among many factors related to bone loss, we consider that estrogen change may play a most important role for the remarkable bone loss in our country.

Absorptiometry, Photon↗
PubMed1995

Site-specific cleavage of chromosomes in vitro through Cre-lox recombination.

Site-specific recombination systems are useful tools for chromosome engineering in vivo and site-specific DNA cleavage methods have applications in genome analysis and gene isolation. Here, we report a new method to fragment chromosomes in vitro using the Cre-lox site-specific recombination system. Two lox sites were targeted into the 5.7 Mb chromosomes I of Schizosaccharomyces pombe. In vitro recombination between chromosomal lox sites and exogenously provided lox oligonucleotides 'cleaved' the chromosome at the defined lox sequences. Site-specific cleavage of lox sites in the tobacco genome was also demonstrated. This recombination-based cleavage method provides a novel approach for structural and functional analyses of eukaryotic chromosomes as it allows direct isolation of chromosome regions that correspond to phenotypes revealed through Cre-lox mediated chromosome rearrangements in vivo. Moreover, recombination with end-labeled lox oligonucleotides would permit the specific end-labeling of chromosome segments to facilitate the long range mapping of chromosomes.

Base Sequence↗
PubMed1995

Intra-chromosomal rearrangements generated by Cre-lox site-specific recombination.

Chromosomal rearrangements are useful genetic and breeding tools but are often difficult to detect and characterize. To more easily identify and define chromosome deletions and inversions, we have used the bacteriophage P1 Cre-lox site-specific recombination system to generate these events in plants. This involves three steps: (i) the introduction of two lox sites into one locus in a plant genome, including one site within a modified Ds transposon; (ii) Ac transposase-mediated transposition of the Ds-lox element to a new locus on the same chromosome; (iii) Cre-mediated site-specific recombination between the two lox sites that bracket a chromosome segment. We report the production of a deletion and three inversion events in tobacco. The utility of chromosomal segments bracketed by lox sites for targeted manipulation and cloning is discussed.

Base Sequence↗
PubMed1994

Cre recombinase-mediated site-specific recombination between plant chromosomes.

We report the use of the bacteriophage P1 Cre-lox system for generating conservative site-specific recombination between tobacco chromosomes. Two constructs, one containing a promoterless hygromycin-resistance gene preceded by a lox site (lox-hpt) and the other containing a cauliflower mosaic virus 35S promoter linked to a lox sequence and the cre coding region (35S-lox-cre), were introduced separately into tobacco plants. Crosses between plants harboring either construct produced plants with the two constructs situated on different chromosomes. Plants with recombination events were identified by selecting for hygromycin resistance, a phenotype expressed upon recombination. Molecular analysis showed that these recombination events occurred specifically at the lox sites and resulted in the reciprocal exchange of flanking host DNA. Progenies of these plants showed 67-100% cotransmission of the new transgenes, 35S-lox-hpt and lox-cre, consistent with the preferential cosegregation of translocated chromosomes. These results illustrate that site-specific recombination systems can be useful tools for the large-scale manipulation of eukaryotic chromosomes in vivo.

Bacteriophage P1↗
PubMed1994

Does alpha 1-acid glycoprotein act as a non-functional receptor for alpha 1-adrenergic antagonists?

The ability of a variety of alpha 1-acid glycoproteins (AAG) to affect the intrinsic activity of the alpha 1-adrenergic antagonist prazosin was studied in rabbit aortic strip preparations. From these studies, the activity of AAG appears to be linked to their ability to bind the antagonist. However, a capability to bind prazosin was not the only requirement for this effect. The removal of sialic acid and partial removal of the galactose and mannose residues by periodate oxidation of human AAG all but eliminated the ability of AAG to affect the intrinsic pharmacologic activity of prazosin, although the binding of prazosin was not significantly affected. The presence of bovine AAG, a protein that has a low ability to bind prazosin, reduced the effect of human AAG on prazosin activity. Based upon these results, we propose that AAG is able to bind in the vicinity of the alpha 1-adrenoceptors, therefore extending the binding region for antagonists in such a way as to decrease the ability of the antagonist to interact with the receptor. The carbohydrate side-chains are important for the binding of AAG in the region of the adrenoceptor.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1994

Analysis of the replication region of a mycobacterial plasmid, pMSC262.

We determined the nucleotide sequence of a DNA fragment which contains the replication region of pMSC262, a Mycobacterium scrofulaceum plasmid used to construct the Mycobacterium-Escherichia coli shuttle vector. The complete sequence of the fragment contained 2,504 bp with an overall G+C content of 69.8%. By deletion analysis, we found that the minimum length required for plasmid replication in M. bovis BCG was about 1.6 kb. Within this region, several open reading frames (ORFs) and a putative replication origin (ori) were identified by computer analysis. One of the ORFs, ORF2, which encodes a putative 28.9-kDa basic protein with characteristics of DNA-binding proteins, appeared to be involved in replication of the plasmid in BCG. By separation of ORF2 and the putative ori region, it was revealed that the relative locations of ORF2 and the putative ori region are likely important for replication in BCG. No DNA or amino acid homologies were found between this replication region and that of pAL5000, another mycobacterial plasmid used for vector plasmid construction. In addition, we found that this replicon did not lead to replication in E. coli and was compatible in BCG with pAL5000-derived vector plasmid pYUB75 (R. G. Barletta, D. D. Kim, S. B. Snapper, B. R. Bloom, and W. R. Jacobs, J., J. Gen. Microbiol. 138:23-30, 1992).

Amino Acid Sequence↗
PubMed1994

[Ocular manifestations of patients with gangliosidosis].

This paper describes the ophthalmological findings in 4 patients with gangliosidosis (GLS). The diagnosis was verified by assaying hexosaminidase A and beta-galactosidase activities with marked deficiency. The presence of a cherry-red spot at the macular region, macular degeneration and atrophy of the optic disc were the main ocular manifestations. The ocular pathological changes seen under light and electron microscopy and the inherited error of metabolism of ganglioside are discussed.

Child, Preschool↗
PubMed1994

Decreased elimination of drug in the presence of alpha-1-acid glycoprotein is related to a reduced hepatocyte uptake.

The mechanism by which human alpha-1-acid glycoprotein (hAAG) decreases the intrinsic clearance of prazosin was investigated in primary rat hepatocyte cultures. The intrinsic clearance, equal to the ratio of rate of drug elimination to unbound concentration, is the composite result of uptake and metabolism. From separate elimination and uptake studies we found that the ability of hAAG to decrease the intrinsic clearance of prazosin was related to decreased uptake and not to changes in metabolism. In order to identify the underlying mechanism for the observed decrease in uptake the effect of bovine alpha-1-acid glycoprotein (AAG) on prazosin intrinsic clearance and uptake was also determined. Bovine AAG, in contrast to hAAG, had neither a statistical significant effect on prazosin uptake nor on prazosin intrinsic clearance. Based upon the fact that bovine AAG has little or no ability to bind prazosin in contrast to hAAG, we hypothesize that when a AAG, capable of binding prazosin, associated with cell membranes it will retard the diffusion of drug through the cellular stagnant diffusion layer. Human serum albumin (HSA), in contrast to hAAG, did not decrease the uptake of prazosin although HSA binds prazosin and associates with hepatocytes to the same degree as hAAG. However, HSA associated with rat hepatocytes, in contrast to hAAG, appears to have an operationally reduced ability to bind prazosin suggesting that HSA may not be able to retard diffusion of prazosin to the same degree as hAAG. HSA also may release prazosin which subsequently serves to increase the active concentration of prazosin at the cell surface.

Animals↗