Search PubMed⌕ Search

Biomedical subjects

M Qiu

Publications and source records attributed to M Qiu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effects of XW630 on bone formation in ovariectomized rats and in human osteoblast-like cells.

OBJECTIVE: To study the effects of XW630 on bone formation in overiectomized (OVX) rats and in human osteoblast-like cell line TE85. METHOD: Bone histomorphometric analysis was performed with undecalcified bone sections and tetracycline intraperitoneally labeling. RESULTS: Compared with that of OVX rats, the static data of trabecular bone volume (TBV)/total tissue volume (TTV), TBV/sponge bone volume (SBV) and mean trabecular plate density (MTPD) were enhanced while mean trabecular plate spacing (MTPS) decreased after treated with XW630 for 13w. The dynamic data of single-labeled surface [Sfract(s)], double-labeled surface [Sfract(d)], Sfract(d+1/2s), trabecular osteoid surface (TOS) and bone formation rate in tissue level (Svf) were increased and osteoid maturation period (OMP) shortened in XW630 group. In osteoblast-like cells, both 3H-thymidine incorporation and cell count increased after treated with XW630 for 48. Treated with XW630 for 12 approximately 18h, inducible nitric oxide synthase (iNOS) activity and cGMP content increased in time-dependent manners. CONCLUSIONS: XW630 enhanced bone activation frequency and increased trabecular connectivity, stability, and strength. The cellular mechanism related to effects of XW630 on bone formation in ovariectomized rats.

Animals↗
PubMed1999

Msx1 is required for the induction of Patched by Sonic hedgehog in the mammalian tooth germ.

We have used the mouse developing tooth germ as a model system to explore the transmission of Sonic hedgehog (Shh) signal in the induction of Patched (Ptc). In the early developing molar tooth germ, Shh is expressed in the dental epithelium, and the transcripts of Shh downstream target genes Ptc and Gli1 are expressed in dental epithelium as well as adjacent mesenchymal tissue. The homeobox gene Msx1 is also expressed in the dental mesenchyme of the molar tooth germ at this time. We show here that the expression of Ptc, but not Gli1, was downregulated in the dental mesenchyme of Msx1 mutants. In wild-type E11.0 molar tooth mesenchyme SHH-soaked beads induced the expression of Ptc and Gli1. However, in Msx1 mutant dental mesenchyme SHH-soaked beads were able to induce Gli1 but failed to induce Ptc expression, indicating a requirement for Msx1 in the induction of Ptc by SHH. Moreover, we show that another signaling molecule, BMP4, was able to induce Ptc expression in wild-type dental mesenchyme, but induced a distinct expression pattern of Ptc in the Msx1 mutant molar mesenchyme. We conclude that in the context of the tooth germ Msx1 is a component of the Shh signaling pathway that leads to Ptc induction. Our results also suggest that the precise pattern of Ptc expression in the prospective tooth-forming region is controlled and coordinated by at least two inductive signaling pathways.

Animals↗
PubMed1999

Expression and regulation of the chicken Nkx-6.2 homeobox gene suggest its possible involvement in the ventral neural patterning and cell fate specification.

Rapid accumulating evidence has suggested that the homeodomain transcription factors of the Nkx family play important roles in controlling vertebrate organ patterning and differentiation. In this study, we report the cloning, expression and regulation of a novel chicken homeobox gene, cNkx-6.2, whose expression is similar, but not identical, to that of mouse Nkx-6.2. The earliest expression of cNkx-6.2 was detected at the neural plate stage in the prospective midbrain and hindbrain regions. As the neural development proceeds, cNkx-6.2 expression was restricted in the ventral region of the entire neural axis except the forebrain region. At late stages of development, cNkx-6.2 expression is downregulated in the ventricular neuroepithelial cells, but subsequently upregulated in a sub-population of cells. Tissue recombination and explant culture experiments demonstrated that expression of cNkx-6.2 can be induced by the notochord signal and purified SHH protein, and repressed by BMP-4 and -7, indicating that the cNkx-6.2 expression can be influenced by both ventral and dorsal midline signals. Taken together, these studies have suggested two different roles for the cNkx-6.2 transcription factor: participating in the Shh-initiated ventral patterning during early CNS development and controlling cell fate specification and differentiation during late development.

Amino Acid Sequence↗
PubMed1999

Relationship between ventral stream for object vision and dorsal stream for spatial vision: an fMRI + ERP study.

Recent imaging studies indicated the existence of two visual pathways in humans: a ventral stream for object and form vision and a dorsal stream for spatial and motion vision. The present study was motivated by a stimulating question: Supposing shape and motion are processed separately in the two pathways, how do the respective cortical areas respond to the stimuli of "forms defined by motion"? fMRI and ERP recordings were combined in order to measure the spatiotemporal activation pattern in the two pathways responding to forms defined by motion, which were produced solely by coherent movement of random dots against a background of dynamic or static random dots. The fMRI data indicated that the stimuli of forms defined by motion indeed activated both dorsal MT/V5 and ventral GTi/GF. Furthermore, the RV curves resulting from fMRI-seeded dipole modeling indicated that each pair of dipoles located at MT/V5 or GTi/GF reached the same best-fit point; a single pair of free dipoles located near the fMRI foci of MT/V5 and GTi/GF could be identified at the corresponding best-fit point; and the source waveforms resulting from fixed dipole modeling also showed simultaneous activation of MT/V5 and GTi/GF dipoles in the time interval around the best-fit point. The present results, therefore, suggest that MT/V5 and GTi/GF appear to be activated in parallel and simultaneously responding to forms defined by motion. Such findings raise interesting issues about the hierarchical organization and the functional specialization in the two pathways.

Adult↗
PubMed1999

[Study of morphologic effects of 4 Chinese herbs by bone histomorphometry in ovariectomized rats].

OBJECTIVE: To study the therapeutic effects of Chinese herbs Drynaria, Cynomorium, Epimedium and Chain Fern on osteoporotic ovariectomized (OVX) rat models. METHODS: 54 Wistar female rats at the age of 3 months were randomly divided into 2 groups: control groups and experimental group. The control group included: normal groups (N), shamed oprations group(S) and ovariectomized group (OVX) (10 in each group); The experimental group: group A (Drynaria), group B (Cynomorium), group C (Epimedium) and group D (Chain Fern) (6 in each group). Each of the experimental groups was fed separately with the 4 Chinese herbs (0.25 g/100 g B.W/day) respectively by mouth every day for 2 months. Double tetracycline labels were carried out on these animals before the sacrifice. Their left tibia was reserved for the preparation of bone specimen and was studied by bone histomorphometry. RESULTS: The percentage of trabecular volume in total bone volume (TV/TBV) decreased significantly in OVX rats as compared with shame group (P < 0.01). However, after treatment with Drynaria or Epimedium, TV/TBV increased significantly as compared with that before treatment (P < 0.05). The surface area of tetracycline label in Drynaria group lowered and osteoid percentage increased in Epimedium group. CONCLUSIONS: The 4 Chinese herbs have some therapeutic effects on osteoporotic rat models. Drynaria and Epimedium appeared to work better.

Animals↗
PubMed1999

[Thermal physiological analysis of man in an Intravehicular Activity space suit].

OBJECTIVE: To analyze the thermal physiological changes of man in a Intravehicular Activity (IVA) space suit. METHOD: Combined second design was used to arrange 24 tests in 6 young male subjects wearing an IVA space suit at sea level. RESULT: The relationship between common thermal physiological measurements and air ventilating parameters (air temperature, flow rate and its relative humidity) together with metabolic state (rest or work) of man were established in mathematical models. Possible applications of these models were illustrated. Metabolic heat production which influences the relations was also discussed. CONCLUSION: Thermal physiological changes of man in the space suit were properly expressed by the mathematical models in this paper.

Adolescent↗
PubMed1999

[Application of enzyme-linked immunosorbent assay for cholecystokinin].

An enzyme-linked immunosorbent assay for octapeptide cholecystokinin (CCK) has been developed. Using this method we distinguished two kinds of CCK-related peptides and is also useful for identified the compounds with CCK-like structure in tissue extracts, as well as different antipeptide antisera. The results showed that this method could be applied to preliminary structure analysis of CCK.

Animals↗
PubMed1998

Molecular cloning and expression of human grap-2, a novel leukocyte-specific SH2- and SH3-containing adaptor-like protein that binds to gab-1.

The SH2- and SH3-containing adaptor molecules serve to recruit cytosolic signal-transducing molecules to the activated receptor tyrosine kinases. In this study, we report the molecular cloning of a novel adaptor-like protein, Grap-2 (Grb-2 related adaptor protein 2), using the multisubstrate docking protein Gab-1 as bait in the yeast two-hybrid system. Sequence analysis revealed that Grap-2 contains a SH3-SH2-SH3 structure that has a high degree of sequence homology to those of the Grb-2 and Grap adaptor molecules. However, unlike in Grap and Grb-2, the SH2 and the C-terminal SH3 domains of Grap-2 are separated by a 120-amino-acid glutamine-rich sequence that shows no apparent homology to any known molecule or structural motif. The C-terminal SH3 domain of Grap-2 alone is sufficient to bind to Gab-1. Furthermore, Northern blot analysis demonstrated that Grap-2 has two major transcripts of 1.4 and 4.0 kb that can only be detected in tissues rich in leukocytes and in two leukemia cell lines. This highly restricted pattern of expression suggests that Grap-2 may participate in leukocyte-specific protein tyrosine kinase signaling.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Construction of a modular yeast two-hybrid cDNA library from human EST clones for the human genome protein linkage map.

Identification of all human protein-protein interactions will lead to a global human protein linkage map that will provide important information for functional genomics studies. The yeast two-hybrid system is a powerful molecular genetic approach for studying protein-protein interactions. To apply this technology to generate a human protein linkage map, the first step is to construct two-hybrid cDNA libraries that cover the entire human genome. With a homologous recombination-mediated approach, we have constructed a modular human EST-derived yeast two-hybrid library in the Gal4 activation domain-based vector, pACT2. Quality analysis of this library indicated that the approach of constructing two-hybrid cDNA libraries from individually arrayed human EST clones is feasible, and such a two-hybrid library is suitable for detecting protein-protein interactions. This is also the first time that a comprehensive two-hybrid system cDNA library has been constructed from a collection of individually arrayed EST clones.

Chromosome Mapping↗
PubMed1998

Cloning and expression pattern of chicken Pitx2: a new component in the SHH signaling pathway controlling embryonic heart looping.

Asymmetry along the left-right axis of the embryo is a vital feature of vertebrate embryogenesis. In this study, we report the isolation and characterization of a bicoid-related homeobox gene, cPitx2, which displays left-right asymmetric expression during early chick embryogenesis. Asymmetric expression of cPitx2 is first detected at stage 7 and is restricted to mesodermal tissues on the left side of the embryo including the left sided lateral mesoderm, the left sided precardiac mesoderm, and the left half epimyocardium of the primitive heart. cPitx2 is also detected in the presumptive blood islands and endothelia of the embryonic blood vessels. Implantation of Sonic hedgehog (SHH) protein soaked beads on the right side of embryos induced ectopic cPitx2 expression on that side. Based on these observations, we suggest that cPitx2 is a component in SHH signaling pathway and plays a role in determining left-right asymmetry and in vasculogenesis during avian embryogenesis.

Amino Acid Sequence↗
PubMed1998

Control of anteroposterior and dorsoventral domains of Nkx-6.1 gene expression relative to other Nkx genes during vertebrate CNS development.

Here we report the isolation, sequence and developmental expression in the central nervous system of several members of the chicken and mouse Nkx gene family. These are among the earliest genes to be regionally expressed in the neural plate; they are expressed just above the axial mesendoderm (prechordal mesendoderm and notochord). Each Nkx gene has a distinct spatial pattern of expression along the anterior-posterior axis of the ventral central nervous system: Nkx-2. 2 is expressed along the entire axis, whereas Nkx-2.1 is restricted to the forebrain, and Nkx-6.1 and Nkx-6.2 are largely excluded from the forebrain. They are also expressed in distinct patterns along the dorsal-ventral axis. These genes are expressed in both the ventricular and mantle zones; in the mantle zone Nkx-6.1 is co-expressed with Islet-1 in a subset of motor neurons. Like other Nkx genes, expression of Nkx-6.1 is induced by the axial mesendoderm and by sonic hedgehog protein. BMP-7 represses Nkx-6.1 expression. While the notochord can induce Nkx-6.1 expression in the anterior neural plate, sonic hedgehog protein does not, suggesting that the notochord produces additional molecules that can regulate ventral patterning.

Amino Acid Sequence↗
PubMed1998

Molecular control of odontogenic patterning: positional dependent initiation and morphogenesis.

We have previously proposed that the patterning of the mammalian dentition is determined by an odontogenic homeobox code, whereby positional specification of odontogenic ectomesenchymal cell populations in a given region of the first branchial arch are determined by the combination of different homeobox genes expressed, described in detail in (1). Here we describe the first functional evidence for such a mechanism, and show that development of different types of teeth is controlled by independent genetic pathways. We suggest a mechanism whereby patterning is determined by position dependent control of tooth germ initiation, and propose that the pathway of morphogenesis is directly linked to the early mesenchymal expression of homeobox genes.

Animals↗
PubMed1998

[Comparative study of tetracycline-estrone and estrone effects on bone histomorphometric parameters in ovariectomized rats].

OBJECTIVE: To compare the effects of tetracycline-estrone (TE) and estrone (E) on bone histomorphometric parameters of femoral distal diaphysis in ovariectomized (OVX) rats. METHODS: Twenty female rats were randomly allocated into four groups, 5 rats in each: tetracycline-estrone (TE), estrone (E), OVX and sham operation (S). The OVX rats were used as a model for osteoporosis. After being fed with TE or E for 13 weeks, all rats were sacrificed. The effects of TE and E on bone microarchitecture and dynamics were studied by bone histomorphometry. RESULTS: The histomorphometric data showed that the connectivity of trabecular bone in TE and E groups was significantly improved in comparision with that in S group (P < 0.05). The dynamic data indicated that in TE and E group, the tetracycline labelled and osteoid surfaces were remarkably increased in comparision with those in OVX group, especially the data in TE group were significantly higher than those in E group and other two groups (P < 0.05). CONCLUSIONS: The connectivity of trabecular bone could be significantly improved by both TE and E. The activation frequency seemed to be higher in TE group than that in E group.

Animals↗
PubMed1998

[Relationship between the toxigenicity and ribotype distribution of Pseudomonas cocovenenans subsp. farinofermentans].

By rDNA fingerprinting technique, ribotype discrimination analysis was conducted for exploring the relationship between the toxigenicity and ribotype distribution of 42 strains of Pseudomonas cocovenenans subsp. farinofermentans. The results showed that 73.8 percent of the strains were toxigenic, which were distributed within the most ribotype and isolated from either food poisoning samples or normal food samples. The other strains were not toxigenic; which were isolated from normal food samples and distributed only within a few ribotypes. Since the most clones of P. cocovenenans subsp. farinofermentans were toxigenic, their potential hazard should be concerned.

Animals↗
PubMed1998

[Study on the molecular epidemiology characteristics of Pseudomonas cocovenenans subsp. farinofermentans isolated from China with rDNA fingerprinting].

After the chromosomal DNA digestion by Bgl II and EcoRV, rDNA fingerprinting for Pseudomonas cocovenenans subsp. farinofermentans was made using biotin-labeled 16S + 23S rDNA as a probe. Fifty one strains of P. cocovenenans subsp. farinofermentans isolated from some areas of China were divided into 20 ribotyes, 52.9 percent of which were RT6, 9 and 2. In most cases, there were 2 or more ribotypes in each province or city. Though same ribotypes were isolated from different provinces, each ribotype existed in part of an area. The ribotype of RT6 was detected in samples from 4 incidents of food poisoning in Guizhou, Jiangsu and Hebei provinces, which indicated that these incidents may be caused by the same clone. With discrimination and cluster analysis of ribotypes, the rDNA fingerprinting may effectively contribute to analyzing the homogeneity of different strains, tracing the transmission route, and exploring the evolution and epidemiological characteristics of P. cocovenenans subsp. farinofermentans.

China↗
PubMed1998

Excitatory amino acids in cerebrospinal fluid and their relations with clinical features and outcomes in acute head injury.

OBJECTIVE: To determine the contents and dynamics of excitatory amino acids (EAAs), glutamate (GLU) and aspartate (ASP) in the cerebrospinal fluid (CSF) of patients with acute head injury and to clarify the relationship of EAAs with clinical features and outcomes. METHODS: Forty-two adults with acute head injury were included. Glasgow coma scale (GCS) obtained at admission and Glasgow outcome scale (GOS) obtained three months post-injury were assessed. Samples of CSF were obtained via ventricular or lumbar puncture every 24 hours. GLU and ASP in CSF were analyzed by reversed-phase HPLC with a fluorescent detector. Nine control subjects were adults with lumbar anesthesia but without neurological diseases. RESULTS: The peak concentration of GLU and ASP of head-injured group was significantly higher than that of the control group. Dynamic research on severely injured ones indicated that the peak value of GLU mostly appeared within 48 hours post-injury; it decreased with the improving or remaining of the neurological status, and increased with the deterioration, but was still higher than that of the control seven days post-injury. The peak value of EAAs of severely injured patients was conspicuously higher than that of mildly injured group. There was a significant negative correlation between the peak values of GCS and EAAs. The peak value of EAAs in patients with poor outcome was remarkably higher than that in patients with good outcome. GOS was closely correlated to the peak value of EAAs. When the concentration of GLU was over 7 mumol/L, the rate of poor-outcome increased markedly. CONCLUSION: The content of EAAs in CSF increases following acute head injury and remains higher at least a week post-injury in severely injured patients. The more severe the trauma, the more obvious the excitotoxicity induced by EAAs; the more serious the secondary brain insult and the brain edema will be, the worse the outcome, naturally.

Adolescent↗