Biomedical subjects

Y Jiao

Publications and source records attributed to Y Jiao.

At least 19 recordsLinked to original sources

PubMed2006

Neuropeptide Y regulates recurrent mossy fiber synaptic transmission less effectively in mice than in rats: Correlation with Y2 receptor plasticity.

A unique feature of temporal lobe epilepsy is the formation of recurrent excitatory connections among granule cells of the dentate gyrus as a result of mossy fiber sprouting. This novel circuit contributes to a reduced threshold for granule cell synchronization. In the rat, activity of the recurrent mossy fiber pathway is restrained by the neoexpression and spontaneous release of neuropeptide Y (NPY). NPY inhibits glutamate release tonically through activation of presynaptic Y2 receptors. In the present study, the effects of endogenous and applied NPY were investigated in C57Bl/6 mice that had experienced pilocarpine-induced status epilepticus and subsequently developed a robust recurrent mossy fiber pathway. Whole cell patch clamp recordings made from dentate granule cells in hippocampal slices demonstrated that, as in rats, applied NPY inhibits recurrent mossy fiber synaptic transmission, the Y2 receptor antagonist (S)-N2-[[1-[2-[4-[(R,S)-5,11-dihydro-6(6H)-oxodibenz[b,e]azepin-11-yl]-1-piperazinyl]-2-oxoethyl]cyclopentyl]acetyl]-N-[2-[1,2-dihydro-3,5(4H)-dioxo-1,2-diphenyl-3H-1,2,4-triazol-4-yl]ethyl]-argininamide (BIIE0246) blocks its action and BIIE0246 enhances synaptic transmission when applied by itself. Y5 receptor agonists had no significant effect. Thus spontaneous release of NPY tonically inhibits synaptic transmission in mice and its effects are mediated by Y2 receptor activation. However, both NPY and BIIE0246 were much less effective in mice than in rats, despite apparently equivalent expression of NPY in the recurrent mossy fibers. Immunohistochemistry indicated greater expression of Y2 receptors in the mossy fiber pathway of normal mice than of normal rats. Pilocarpine-induced status epilepticus markedly reduced the immunoreactivity of mouse mossy fibers, but increased the immunoreactivity of rat mossy fibers. Mossy fiber growth into the inner portion of the dentate molecular layer was associated with increased Y2 receptor immunoreactivity in rat, but not in mouse. These contrasting receptor changes can explain the quantitatively different effects of endogenously released and applied NPY on recurrent mossy fiber transmission in mice and rats.

Animals↗

PubMed2006

Single-cell RT-PCR, in situ hybridization histochemical, and immunohistochemical studies of substance P and enkephalin co-occurrence in striatal projection neurons in rats.

Single-cell RT-PCR studies in 3-4-week-old rats have raised the possibility that as many as 20% of striatal projection neurons may be a unique type that contains both substance P (SP) and enkephalin (ENK). We used single-cell RT-PCR, retrograde labeling, in situ hybridization histochemistry, and immunolabeling to characterize the abundance of this cell type, its projection target(s), and any developmental changes in its frequency. We found by RT-PCR that 11% of neurons containing either SP or ENK contained both in 4-week-old rats, while in 4-month-old rats SP/ENK colocalization was only 3%. SP-only neurons tended to co-contain dynorphin and ENK-only neurons neurotensin, while SP/ENK neurons tended to contain dynorphin. Single-cell RT-PCR showed SP/ENK co-occurrence in 4-week-old rats to be no more common among striatal neurons retrogradely labeled from the substantia nigra than among those retrogradely labeled from globus pallidus. Double-label in situ hybridization showed SP/ENK perikarya to be scattered throughout striatum, making up 8% of neurons containing either SP or ENK at 4 weeks, but only 4% at 4 months. Immunolabeling showed that presumptive striatal terminals in globus pallidus externus, globus pallidus internus and substantia nigra pars reticulata that colocalized SP and ENK were scarce. Terminals colocalizing SP and ENK were, however, abundant in the substantia nigra pars compacta. Thus, SP-only and ENK-only neurons make up the vast majority of striatal projection neurons in rats, the frequency of SP/ENK colocalizing striatal neurons is low in adult rats (3-4%), and SP/ENK colocalizing neurons primarily project to SNc but do not appear to be confined to striosomes.

Age Factors↗

PubMed2001

Dynamic interactions of p53 with DNA in solution by time-lapse atomic force microscopy.

Dynamic interactions of the tumor suppressor protein p53 with a DNA fragment containing a p53-specific recognition sequence were directly observed by time-lapse tapping mode atomic force microscopy (AFM) in liquid. The divalent cation Mg(2+) was used to loosely attach both DNA and p53 to a mica surface so they could be imaged by the AFM while interacting with each other. Various interactions of p53 with DNA were observed, including dissociation/re-association, sliding and possibly direct binding to the specific sequence. Two modes of target recognition of p53 were detected: (a) direct binding, and (b) initial non-specific binding with subsequent translocation by one-dimensional diffusion of the protein along the DNA to the specific site.

Aluminum Silicates↗

PubMed2001

[Significance of her2 oncogene expression in primary nasopharyngeal carcinoma].

OBJECTIVE: To investigate the status of her2 oncogene at DNA level and the molecular mechanism of overexpression of her2 oncoprotein in part of patients with nasopharyngeal carcinoma (NPC). METHODS: Forty-five cases of PNC tissue and fifteen cases of normal epithelial tissue adjacent to tumor tissue were examined for her 2 signal and centromere 17 signal. Interphase fluorescence in situ hybridization (FISH) was used to examine the copy number of her 2 and immunohistochemical (IHC) staining were used to analyze the copy number and protein expression of her2. RESULTS: There were 1.92% +/- 0.10% her2 signals per nucleus in normal epithelial tissue adjacent to tumor. 75.52 +/- 9.33% of the nuclei contained 2 her2 signals and 2 centromere 17 signals. No alteration in gene copy number was found in cancerous nuclei. However, IHC staining of the 45 tumors with antibody against her2 showed that overexpression of her2 oncoprotein occurred in 33% (15/45) of NPC. However, there was no significant correlation between her2 expression and sex, age, clinical staging, and clinical outcome of patients. CONCLUSION: The overexpression of her2 in NPC does not relate to her2 gene amplification. Immunohistochemistry may not be a good measure to examine her2 expression. The mechanism of her2 oncoprotein overexpression and its biological significance in the development of NPC remain to be elucidated.

Adult↗

PubMed2001

A new glycogen synthase activity ratio in skeletal muscle: effects of exercise and insulin.

It was recently reported that MnSO4 stimulates glycogen synthase-dependent glucose transfer from UDPglucose into trichloroacetic acid precipitable endogenous glycoproteins (GSMn(T)) in human muscle extracts. To determine the physiologic significance of this reaction, we compared a new GS activity ratio, GSMn(T)/GSH(E) (where GSH(E) represents the usual glucose transfer to ethanol precipitable exogenous glycogen by GS at 7.2 mM glucose 6-phosphate), with the generally used GSL(E)/GSH(E) ratio (where GSL(E) represents glucose transfer at 0.17 mM glucose 6-P concentration). Biopsies were obtained from the quadriceps femoris muscle of healthy subjects at rest, after 40 min of bicycle exercise at approximately 65% of maximal oxygen uptake and after isometric contraction at 2/3 maximal force to fatigue (approximately 1 min). GSMn(T)/GSH(E) increased from 0.012+/-0.002 at rest to 0.054+/-0.008 (P<0.01) after 40 min of bicycle exercise and the increase in GSMn(T) activity was strongly related to the decrease in endogenous glycogen (i.e.. increase in short-chain endogenous glycoproteins) (r=0.90; P<0.05). On the other hand, GSL(E)/GSH(E) did not change significantly after bicycle exercise (rest = 0.49+/-0.04; exercise = 0.58+/-0.08, P>0.05). GSMn(T)/GSH(E) increased from 0.010+/-0.001 at rest to 0.016+/-0.002 (P<0.05) after isometric exercise, whereas GSL(E)/GSH(E) decreased from 0.27+/-0.04 to 0.20+/-0.02 (P<0.05) under corresponding conditions. Last, insulin, which stimulates glycogen synthesis, also increased GSMn(T)/GSH(E) (1.8-fold, P<0.05), as well as GSL(E)/GSH(E) (1.4-fold, P<0.05), in isolated rat soleus muscle. These data indicate that GSMn(T)/GSH(E) is influenced by endogenous substrate availability and covalent modification. Therefore, GSMn(T)/GSH(E) ratio may prove to be a useful alternative to other GS activity ratios that only reflect changes in the phosphorylation state of GS.

Exercise↗

PubMed2001

Functional receptor-channel coupling compared in contractile and proliferative human vascular smooth muscle.

We have previously identified a human vascular smooth muscle clone that can reversibly convert between proliferative and contractile phenotypes. Here we compared receptor-channel coupling in these cells using fura-2 to monitor [Ca(2+)](i) and patch-clamp to record currents. Histamine elevated [Ca(2+)](i) in all cells and caused contraction of cells exhibiting the contractile phenotype. The rise of [Ca(2+)](i) persisted in Ca(2+)-free solution and was abolished by thapsigargin, indicating involvement of stores. Whole cell electrophysiological recording revealed that histamine evoked transient outward K(+) current, indicating functional receptor-channel coupling. The time-course and amplitude of the histamine-activated current were similar in cells of the proliferative and contractile phenotypes. Moreover, a large conductance K(+) channel was recorded in cell-attached patches and was activated by histamine as well as the Ca(2+) ionophore A-23187, identifying it as the large conductance Ca(2+)-dependent K(+) channel. This K(+) channel showed similar characteristics and activation in both proliferative and contractile phenotypes, indicating that expression was independent of phenotype. In contrast, histamine also elicited an inward Cl(-) current in some contractile cells, suggesting differential regulation of this current depending on phenotype. These studies demonstrate the usefulness of this human vascular cell clone for studying functional plasticity of smooth muscle, while avoiding complications arising from extended times in culture.

Calcimycin↗

PubMed2001

Altered glycogen synthase and phosphorylase activities in skeletal muscle of tetraplegic patients.

Despite marked differences in both the extent of physical activity and in muscle metabolism and structure between tetraplegic and control subjects, the glycogen content in the skeletal muscle of both groups is similar. We determined whether this similarity could be explained by the activities of key enzymes of glycogen metabolism. Muscle biopsies were analysed for glycogen synthase (GS) and glycogen phosphorylase (GP) activities, as well as for metabolites. Glycogen content did not differ significantly between the two groups. Total glycogen synthase activity was reduced by almost 60 % in tetraplegics (P < 0.01), whereas total phosphorylase activity did not differ between groups. GS fractional activity did not differ between groups, whereas phosphorylase fractional activity (-/+ AMP) was significantly higher in the tetraplegics (0.08 +/- 0.01, control; 0.25 +/- 0.02, tetraplegics; P < 0.001). Neither uridine diphosphate (UDP)-glucose nor glucose 6-phosphate (G-6-P) content in muscle differed significantly between groups. These data demonstrate that, in tetraplegics, muscle glycogen content is preserved despite decreases in GS activity and increases in phosphorylase fractional activity. Muscle paralysis has differential effects on the activities of GS and GP. Experimental Physiology (2001) 86.2, 205-209.

Adult↗

PubMed2001

[Interleukin-1 increase nitric oxide synthesis through up-regulation of inducible nitric-oxide synthase by rabbit mandibular condylar cartilage cells in vitro].

OBJECTIVE: To investigate the influence of IL-1 on the biosynthesis of nitric oxide by rabbit mandibular condylar cartilage (MCC) cells. METHODS: MCC cells of white rabbits were harvested enzymatically and cultured in DMEM supplemented with 0.4% newborn calf serum. In the experiment, a variety of concentrations of IL-1 were added to the medium. NO production was determined as nitrite accumulation in the medium. The effects of IL-1 on the mRNA levels of inducible nitric-oxide synthase (iNOS) were assessed by mRNA in situ hybridization method. RESULTS: IL-1 can significantly increase nitric oxide synthesis by MCC cells in a concentration-dependent manner. In addition, normal MCC cells had light expression of iNOS expression and IL-1 (10-100 micrograms/L) promoted the expression of iNOS. CONCLUSIONS: IL-1 can inhibit the chondrocytes proliferation and induce apoptosis that might be through the way of up-regulation of iNOS expression.

Animals↗

PubMed2001

[Study on nuclear DNA content and image cytometry in cervical cancer and precursor lesions].

OBJECTIVE: The aim of this research was to study the biological and clinical features of cervical cancer and precursor lesions. METHODS: Nuclear DNA was analyzed by image cytometry (ICM) in 125 embedded tissue 5 microns sections stained with Feulgen stain. Samples included normal cervical squamous epithelium (n = 11), cervical intraepithelial neoplasia I (CIN I) (n = 22), CINII (n = 17) and CINIII (n = 13), cervical neoplasm (n = 62). RESULTS: The mean DNA content, nuclear area increased progressively from normal cervical epithelium, CINI, CINII, CINIII to invasive squamous carcinoma. Statistical analysis revealed significant difference (P < 0.05, < 0.01). Histograms of cellular DNA ploidy distribution showed different pattern, where 9 components (9C) cells were observed in cervical cancer and CINIII. No differences in DNA mean ploidy (DMP), DNA index (DI) and nuclear area were observed between cervical neoplasm. CONCLUSIONS: It is increased progressively from normal cervical epithelium to cancer, in which CINIII is turning point.

Adult↗

PubMed2001

[Culture and cryopreservation of human mandibular condylar cartilage cells].

OBJECTIVE: To establish an effective way in cryopreserving mandibular condylar cartilage cells. METHODS: Human mandibular condylar cartilage (MCC) cells were harvested and amplified by microcarrier culture technique. MCC cells were preserve in liquid nitrogen. The biological properties of cryopreserved MCC cells were investigated. RESULTS: Cells from liquid nitrogen preservation kept their phenotypic, proliferative an metabolic characteristics of MCC cells in vivo. CONCLUSIONS: Cryopreservation of MCC cells can supply adequate qualified cells for repairing the defects of mandibular condyle cartilage and temporomandibular joint disk.

Cartilage↗

PubMed2000

Genetic alterations in DNA diploid, aneuploid and multiploid colorectal carcinomas identified by the crypt isolation technique.

Loss of heterozygosity (LOH) and microsatellite instability (MSI) commonly occur in colorectal carcinomas. However, the role of these genetic alterations in determining DNA ploidy status of tumors (diploid, aneuploid and multiploid) remains unclear. In the present study, we attempted to clarify the relationship between genetic alterations and DNA ploidy status. Crypt isolation coupled with DNA cytometric sorting and polymerase chain reaction assay (17 microsatellite markers) were used to study allelic losses and MSI in 59 colorectal carcinomas (diploid, 15; aneuploid, 10 and multiploid, 34). Of the 15 diploid carcinomas, 6 exhibited MSI in which allelic losses were rarely found. The other 9 diploid tumors mostly exhibited allelic losses, but none displayed MSI status. Whereas allelic losses frequently occurred in the aneuploid carcinomas and the aneuploid populations of multiploid carcinomas, they were rarely detected in the diploid populations of multiploid carcinomas. MSI status was not observed in aneuploid carcinomas nor in either population of multiploid carcinomas. Although multiploid carcinomas genetically resemble aneuploid carcinomas in the expression of the severe LOH phenotype, the genetic alterations seen in the diploid populations of multiploid carcinomas may differ from those of diploid carcinomas. Furthermore, all diploid, aneuploid and both the diploid and aneuploid fractions of the multiploid tumors that were non-MSI exhibited a high rate of LOH, suggesting that LOH is independent of the tumor's ploidy status.

Adenocarcinoma↗

PubMed2000

Pathway tracing using biotinylated dextran amines.

Biotinylated dextran amines (BDA) are highly sensitive tools for anterograde and retrograde pathway tracing studies of the nervous system. BDA can be reliably delivered into the nervous system by iontophoretic or pressure injection and visualized with an avidin-biotinylated HRP (ABC) procedure, followed by a standard or metal-enhanced diaminobenzidine (DAB) reaction. High molecular weight BDA (10 k) yields sensitive and exquisitely detailed labeling of axons and terminals, while low molecular weight BDA (3 k) yields sensitive and detailed retrograde labeling of neuronal cell bodies. The detail of neuronal cell body labeling can be Golgi-like. BDA tolerates EM fixation and processing well and can, therefore, be readily used in ultrastructural studies. Additionally, BDA can be combined with other anterograde or retrograde tracers (e.g. PHA-L or cholera toxin B fragment) and visualized either by multi-color DAB multiple-labeling - if permanent labels are desired, or by using multiple simultaneous immunofluorescence - if fluorescence viewing is desired. In the same manner, BDA pathway tracing and neurotransmitter immunolabeling can be combined. Note that BDA pathway tracing can also be combined with anterograde or retrograde labeling with fluorescent dextran amines, if one wishes to exclusively use tracers with the favorable transport properties and sensitivities of dextran amines. In this case, the BDA can be visualized together with the fluorescent dextran amines using fluorescence labeling for the BDA, or the fluorescent dextran amines can be visualized together with the BDA by multicolor DAB labeling via immunolabeling of the fluorescent dextran amines using anti-fluorophore antisera. BDA is, thus, a flexible and valuable pathway tracing tool that has gained widespread popularity in recent years.

Animals↗

PubMed2000

Identification of the anterior nucleus of the ansa lenticularis in birds as the homolog of the mammalian subthalamic nucleus.

In mammals, the subthalamic nucleus (STN) is a glutamatergic diencephalic cell group that develops in the caudal hypothalamus and migrates to a position above the cerebral peduncle. By its input from the external pallidal segment and projection to the internal pallidal segment, STN plays a critical role in basal ganglia functions. Although the basal ganglia in birds is well developed, possesses the same major neuron types as in mammals, and plays a role in movement control similar to that in mammals, it has been uncertain whether birds possess an STN. We report here evidence indicating that the so-called anterior nucleus of the ansa lenticularis (ALa) is the avian homolog of mammalian STN. First, the avian ALa too develops within the mammillary hypothalamic area and migrates to a position adjacent to the cerebral peduncle. Second, ALa specifically receives input from dorsal pallidal neurons that receive input from enkephalinergic striatal neurons, as is true of STN. Third, ALa projects back to avian dorsal pallidum, as also the case for STN in mammals. Fourth, the neurons of ALa contain glutamate, and the target neurons of ALa in dorsal pallidum possess AMPA-type glutamate receptor profiles resembling those of mammalian pallidal neurons. Fifth, unilateral lesions of ALa yield behavioral disturbances and movement asymmetries resembling those observed in mammals after STN lesions. These various findings indicate that ALa is the avian STN, and they suggest that the output circuitry of the basal ganglia for motor control is similar in birds and mammals.

Animals↗

PubMed2000

Ultrastructural architecture and mechanical properties of attachment pads in Tettigonia viridissima (Orthoptera Tettigoniidae).

Natural releasable attachment systems of insect legs, where attachment-detachment performances are often very fast, seem to be optimized to get a maximum of real contact to the substratum. Tarsi of Tettigonia viridissima bear flexible attachment pads with unusual ultrastructural architecture of the cuticle. The indentation of the attachment pads was measured under different loads using a force-tester. Since the mechanical properties are influenced by material structure, the freeze-substitution experiments were undertaken to investigate the influence of loads on material structure. Both profile changes of the surface and the orientation of cuticle microfibrils were visualized by means of scanning electron microscopy followed by fracturing of the frozen material. The results show that the flexible pad material deforms replicating the substrate profile down to the micrometer roughness. The pad material showed both elastic and viscous behavior under loads. Elastic deformation of the pad occurred under normal force applied for 4-6 s (elastic modulus 27.2 +/- 11.6 kPa). Two viscous relaxation processes were found, of time constants tau1 = 1.88+/-0.616 s and tau2 =41.2 +/- 9.95 s. Low stiffness of material studied here aids in surface replication and increase of area of real contact between the pad and the underlying substrate.

Animals↗

PubMed2000

Adhesion measured on the attachment pads of Tettigonia viridissima (Orthoptera, insecta).

The tarsi of the cricket Tettigonia viridissima bear flexible attachment pads that are able to deform, replicating the profile of a surface to which they are apposed. This attachment system is supplemented by a secretion produced by epidermal cells and transported onto the surface of the pad through the pore canals of the pad cuticle. This study shows that the secretion alone is necessary, but not sufficient, for adhesion. To account for the full adhesive force, the deformation of the pad and the resulting changes in contact area were considered. In two series of experiments, the adhesive properties of the secretion and the adhesion of the whole pad were measured using a force tester, the sensitivity of which ranged from micronewtons to centinewtons. The adhesive forces of the secretion measured between a smooth sapphire ball with a diameter of 1.47 mm and a flat silicon surface ranged from 0.1 to 0.6 mN. In a control experiment on the silicon surface without secretion, no adhesive force was measured. There was no dependence of the adhesive force on the applied compressive force. When an intact pad was pulled off a flat silicon surface, the adhesive force increased with increasing applied compressive force, but it did not increase further once the applied force exceeded a certain value. The saturated adhesive force, ranging from 0.7 to 1.2 mN, was obtained at applied forces of 0.7-1.5 mN. The hemispherical surface of the pad had a larger contact area and demonstrated greater adhesion under a larger applied force. Adhesion became saturated when a pad was deformed such that contact area was maximal. The tenacity (the adhesive force per unit area) was 1.7-2.2 mN mm(-)(2).

Adhesiveness↗

PubMed2000

[Evaluation of plant protectants against pest insects].

An interference index of population control (IIPC) was constructed for investigating the complex effects of plant protectants, including the effects of repelling insect pests away from the plant, deterring the egg laying of adults and the continuation of feeding, and causing death by toxicity. At the same time, indicated by IIPC, the alcohol extracts of some common plants, such as Eucalytus rubusta, Wedelia chinensis etc. and the neem oil gave very good results to protect the plant against Plutella xylostella. The D-C-Tron NR Petroleum Spray Oil (CALTEX) also gave an excellent effect to protect citrus against red mite. All the experiments show the important role of the repellent effect on the pests.

Animals↗

PubMed2000

[Effects of various growth factors on human mandibular condylar cartilage cell proliferation].

OBJECTIVE: To investigate the effects of transforming growth factor-beta 1 (TGF-beta 1) insulin-like growth factor I (IGF-I) and basic fibroblast growth factor(bFGF) on human mandibular condylar cartilage (MCC) cell proliferation. METHODS: Isolated human MCC cells were cultured in DMEM supplemented with 10% newborn calf serum(NCS). The second passages were used in order to avoid chondrocyte dedifferentiation. Cells were seeded at 2 x 10(4)/well on 96-well plate. After synchronization, medium was replaced by DMEM containing 0.4% NCS or 10% NCS with various growth factors, concentrations and combinations. Dose-response and time-course were studied by MTT colorimetric method. RESULTS: In 0.4% serum containing medium, bFGF stimulated the proliferation moderately, whereas TGF-beta 1 and IGF-I had less effect. In 10% NCS condition, all three growth factors had mitogenic effect and acted dose-dependently. The effects were significant after three days. Among them, bFGF was a potent mitogen(increased by 65%), IGF-I the next(24%). The effect of TGF-beta 1 (13%) might be mediated by some other factors in the serum. The synergetic effects were achieved when they were used in combination. CONCLUSION: It is suggested that optimal combination of growth factors can promote the proliferation of MCC cells significantly, this might be an ideal way in dealing with cartilage damage during pathogenesis.

Cartilage↗

PubMed2000

[A quick way in isolation and amplification of mandibular condylar cartilage cell in vitro].

OBJECTIVE: To establish a quick way in acquiring well differentiated mandibular condylar cartilage (MCC) cells with high viability in large scale. METHODS: Japan white rabbit MCC cells were harvested by enzymatic method. They were grown in a modified bioreactor culture system, which contained the cytodex-3 micro-carriers in the culture medium. Kinetic growth of MCC cells on DEAE-dextran micro-carrier was observed under phase contrast microscope and environmental scanning microscope respectively. RESULTS: MCC cells attached rapidly to the surface of micro-carriers, but their spreading was slow. A quick growth of these cells was observed when they fully spread onto the micro-carrier. The number of MCC cells increased 16.2 times compared with that of plating. CONCLUSIONS: Micro-carrier culture of MCC cells can yield a large quantity of cells within a short period of time that will be of benefit in banking MCC cells for reconstruction of impaired cartilage.

Animals↗