Biomedical subjects

Q Zhou

Publications and source records attributed to Q Zhou.

At least 109 records · Page 6Linked to original sources

PubMed2001

[Effect of pH on nodulation of soybean rhizobia from Weifang and Huayuankou soils].

The effect of pH on the nodulation of Sinorhizobium fredii and Bradyrhizobium japonicum was examined by analyzing the indigent soybean rhizobia, predominant indigent rhizobia, and specific rhizobia, respectively. The results showed that very acid and very alkaline environment could retard the nodulation and inhibit the growth of the rhizobia. Sinorhizohium fredii could endure environment more strongly than Bradyrhizobium japonicum, and had a high competitive nodulation capacity. Bradyhizobium japonicum could endure acid environment more strongly than Sinorhizobium fredii. In very acid and very alkaline environment, the nodulation capacity of S. fredii and B. japonicum was mainly determined by their physiological characteristics.

Bradyrhizobium↗

PubMed2001

Interaction of hypertension and diabetes on impairment of endothelial function.

OBJECTIVE: To investigate whether the interaction of hypertension and diabetes aggravates endothelial dysfunction and leads to smooth muscle dysfunction. METHODS: Noninvasive methods were used to the investigated patients with type 2 diabetes mellitus (2-DM) (Group 1), patients with hypertension (Group 2) and patients with both 2-DM and hypertension (Group 3), as well as a normal control group (Group 4) by studying a brachial artery without evidence of atherosclerotic plaque formation. RESULTS: Results showed that endothelium-dependent vasodilation decreased significantly in Group 1 (5.74% +/- 3.32%, P < 0.05), Group 2 (4.14% +/- 2.93%, P < 0.01), and Group 3 (2.78% +/- 2.08%, P < 0.001) as compared to the control (9.45% +/- 3.88%). The nitroglycerin-induced vasodilation (smooth muscle function) in Group 3 was significantly decreased as compared to the control group (14.11% +/- 4.63% vs 23.53% +/- 6.77%, P < 0.001), but there were no differences in nitroglycerin-induced vasodilation between Group 1, Group 2 and Group 4. On univariate analysis, a reduced vasodilator response to nitroglycerin was associated with endothelium-dependent vasodilation (r = 0.54, P < 0.001). CONCLUSION: Our results indicate that the interaction of 2-DM and hypertension aggravates endothelial dysfunction and further impairs the smooth muscle function.

Aged↗

PubMed2001

[Simulation and display methods of spatial data in landscape ecology].

Simulating and display ecological data over large geographic areas require much time, many resources, and considerable special training. Based on the latest researches all over the world, 7 simulation methods of ecological spatial data and 4 data display formats were reviewed, and several sampling ways were also discussed. Sample density and its spatial distribution, spatial dependence, and estimation accuracy were primarily considered to be the major factors influencing surface representation.

Computer Simulation↗

PubMed2001

[Influence of planting density and precipitation on N2O emission from a winter wheat field].

To investigate the impact of plant density on N2O emission from winter wheat field and the cause of seasonal variation in the emission, field experiment with four planting rates of 0, 90, 180 and 270 kg/ha was conducted at the Jiangning County near Nanjing during 1999-2000 winter wheat growing season. Data of the field measurements indicated that the N2O emission rates during the season from planting to overwintering were not influenced by the plant density, while the emission was positively correlated with the planting density during the season from turning green to maturity. The emissions from the field plots with planting rates of 0 and 90 kg/ha were not found to be significantly different. A further analysis suggested that the seasonal variation of N2O emission be mainly influenced by precipitation, which could be quantitatively described by an exponential function of a weighted average precipitation of 6-day period before measurement.

Agriculture↗

PubMed2001

[Effects of calcium on biological characteristics of wheat seedlings under ultraviolet-B radiation stress].

Under simulated ultraviolet-B radiation (UV-B, 280-320 nm), effect of calcium on biological characteristics of wheat seedlings was studied with pot culture experiment. The results showed that the growth indexes of wheat seedlings on ground and underground in calcium concentration 2 mmol/L treated group were obviously reduced than that of wheat seedlings in control treated group (the descending range of 8.1%-36.1%) under UV-B stress (0.35 W/m2, 6 h per day, for 7 day). And the decreasing degree of growth indexes (3.2%-28.6%) for wheat seedlings in calcium concentration 6 mmol/L treated group were lower than in calcium concentration 2 mmol/L treated group. The experiment proved that calcium can mitigate the damage of ultraviolet-B radiation on wheat seedlings, and this effect was related to that calcium affected physiological and biochemical characteristics of wheat seedlings.

Calcium↗

PubMed2001

[A matched case-control study on direct economic costs of four kinds of nosocomial infections].

OBJECTIVE: To evaluate the direct economic costs of four major kinds of nosocomial infections such as nosocomial pneumonia, urinary tract infection, deep surgical wound infection and intracranial infection. METHODS: A matched case-control study was conducted among 95 pairs of hospitalized patients to investigate the direct economic costs of nosocomial infections. RESULTS: The average medical cost for patients in the case group was 38 741 RMB Yuan, 20 365 Yuan more than that in the control group patients (P < 0.0001). The largest part of extra costs was found in drug expenses, taking up 62.07%, while other extra costs such as non-drug therapies, blood transmission and laboratory examinations, accounted for 10.32%, 7.40% and 5.72% respectively. Extra economic burden caused by nosocomial infections varied in different degrees with different departments, with the heaviest found in the department of tumourology and hematology at an average extra cost of 34 944 Yuan. The average extra charges in case group caused by nosocomial pneumonia, urinary tract infection, deep surgical wound infection and intracranial infection were 31 940 Yuan, 7 436 Yuan, 17 332 Yuan and 17 349 Yuan respectively. The average length of hospital stay was 50.57 days in case group and 25.22 days in control group, showing a 25.53 extra days (P < 0.0001) of hospitalization due to nosocomial infections. CONCLUSION: Nosocomial infections had significantly added to the economic burden of managing the underlying diseases, led to prolonged hospitalization of the patients and lowered the turnover rate of hospital bed. There is a need to call for better infection control program, which would bring tremendous social and economic profits.

Case-Control Studies↗

PubMed2001

[Comparison of production and characters of antisera from rabbits and laying hens].

Rabbits and laying hens were immunized with the conjugate of aflatoxin B1 oxime and bovine serum albumin (AFB1 O-BSA). The production processes, titers and specificities of antisera from rabbits and laying hens were investigated. In rabbits, the antisera started to be obviously produced after 60 days when the conjugate was firstly injected, reached peaks after 120 days, and began to go down after 135 days; while in laying hens, the antisera started to be largely produced after 90 days of the first injection, arrived to peaks after 135 days, and began to go down after 165 days. The maximum enzyme linked immunosorbent assay(ELISA) titer of rabbits' antisera was up to 1:30,000, whereas the maximum ELISA titer was only 1:8000 in laying hens. There are no apparent difference in the sensitivities and specificities of rabbits' and laying hens' antisera. Both antisera from rabbits and from laying hens can be used as ELISA reagents detecting AFB1 in agricultural commodities.

Aflatoxin B1↗

PubMed2001

[Study of blood dynamics of ophthalmic artery in patients with sudden sensorineural hearing loss using color Doppler flow imaging].

OBJECTIVE: To investigate the relationship between the pathogenesis of sudden sensorineural hearing loss (SSHL) and the disorder of blood circulation in inner ear. METHOD: Blood dynamics of the ophthalmic artery were studied quantitatively using color doppler imaging in 34 patients with SSHL. RESULT: Compared with 34 self-controls and 15 normal controls, 28 patients (82.4%) with SSHL had significantly lower blood flow velocities and higher resistance indices (P < 0.05), and there was no significant difference between the self-control group and the normal control group (P > 0.05). CONCLUSION: The study suggested that the blood situations--the decreased blood flow velocities and perfusion and increased resistance of ophthalmic artery in patients with SSHL maybe play a role in the pathogenesis of SSHL.

Adolescent↗

PubMed2001

[The clinic treatment of traumatic optic neuropathy].

OBJECTIVE: To observe the visual outcome of traumatic optic neuropathy treated with optic canal decompression surgery and medication. METHOD: 15 patients, suffering from traumatic optic neuropathy, had received medication and optic canal decompression surgery through the approach of ethmoid and sphenoid sinus. The vision acuity was divided into 5 grades: no light perception, light perception, finger movement, counting fingers, vision > or = 0.1, the vision acuity improvements reaching 2 grades or more were determined as effective. All patients were followed up for intervals of 1 month and 6 months. RESULT: The total efficient rate is 57.4%, no intraoperative or postoperative complications were encountered. Being followed up 6 months, 2 cases, who underwent respectively the operation 8, 11 days after trauma, felt no light perception. CONCLUSION: The approach through ethmoid and sphenoid sinus have the merits such as safety, less damage and larger operative field. Timely medication, megacorticosteroid therapy mainly, may play a good role in alleviating optic nerve edema and restoring its function. Comprehensive therapy may be an ideal treatment to traumatic optic neuropathy.

Adolescent↗

PubMed2001

[Evaluation of positron emission tomography in diagnosing and staging of lung cancer].

OBJECTIVE: To evaluate positron emission tomography (PET) in diagnosing and staging of lung cancer. METHODS: One hundred and forty-seven patients (93 with lung cancer, 15 with lung metastatic tumors, 39 with benign lesions) were involved in the study. 163 whole body examinations (twice in 12 cases and 3 times in 2 cases) were performed after injection of 18F-fluro-deoxy-glucose (18FDG) with a Siemens ECAT EXACT HR + PET system. The results of PET were compared with pathological diagnoses (112 cases), clinical follow-up (35 cases), CT (68 malignant and 30 benign cases), and other imaging diagnoses. RESULTS: For the 147 cases with lung lesions, the sensitivity, specificity, and accuracy of FDG PET in differentiating the malignant from the benign were 97.2%, 89.7%, and 94.6% respectively. For the 93 lung cancer cases, more lesions were detected by PET in 58 (62.4%) cases, and changed staging in 36 (38.7%). In the 98 cases examinations, PET positive findings were consistent with CT in 39 (39.8%) cases; PET detected more lesions than CT in 29 (29.6%) cases; the lesions detected by CT were negative or with low uptake in the PET images in 30 (30.6%) cases, and they were finally proved as benign by follow-up. However, CT provided better detailed anatomical structures of the lesions than PET, and image fusion should give more information about the lesions. CONCLUSIONS: FDG PET had advantages in diagnosing and staging of lung cancer by providing metabolic information of the lesions. Comparison and fusion of PET with CT will give much help to clinical diagnosis.

Fluorodeoxyglucose F18↗

PubMed2001

[Direct determination of rhizoma cimicifuga by FTIR spectroscopy].

Fifteen samples of original plants of Rhizoma Cimicifuga were determined quickly and directly with the method of FTIR and comparing software. The results showed that the spectra of these samples were characteristic relying on the difference of chemical components and their content of related components. The difference of spectra among samples belonging to different families was distinct, and in different species with same genus too. To the same species, between two samples with different producing areas, or with same producing area but different collection date, the spectra were not obvious. This approach provide a quickly and accurately determination method of crude drug without extraction and separation.

Cimicifuga↗

PubMed2001

[Studies of black roller pen inks by NIR FT-Raman spectrometry].

36 kinds of black roller pen inks collected from Chinese market were analyzed by NIR FT-Raman spectroscopic technique and they were divided into 10 groups (from A to J group) according to their characteristic Raman spectra. Based on studying main component of roller pen inks and peculiarity of Raman spectrum by documents, the main Raman peaks of each group of roller ball inks were interpreted particularly. It have also been investigated that the influence factors from paper matrix, humidity of the samples, laser power and writing time, especially the forth item showed some relationships of the peak intensity ratio with the relative age of inks. This method is speediness, convenience, high sensitivity and no ink-extraction process. The insufficiency of the method is that fluorescence and heat background comes forth when a few samples were irradiated by laser.

Forensic Medicine↗

PubMed2000

The n-alcohol site in the nicotinic receptor pore is a hydrophobic patch.

Alcohols and volatile anesthetics inhibit peripheral nicotinic acetylcholine receptors noncompetitively, primarily via an open-channel block mechanism. Analysis of hydrophobic mutations near the middle of the pore-forming M2 domains suggested that alcohols interact with the pore in this vicinity. To establish the extent of this inhibitory site, we created a series of hydrophobicity-altering mutations scanning most of the alpha subunit M2 domain. Using both single-channel and rapid patch perfusion electrophysiology, we measured how these mutations affect nAChR sensitivity to ethanol and hexanol. We find a near-contiguous series of amino acids in alpha-M2, extending from alphaL250 (8') to alphaV255 (13'), where mutagenesis strongly influences inhibition by alcohols. These results support the existence of a large inhibitory patch in the nAChR pore lining where interactions with alcohols are primarily due to hydrophobic forces. Ethanol appears to interact with deeper regions of this site than does hexanol. Because alcohols apparently act as open-channel blockers, we infer from our results that most of the residues between alphaL250 and alphaV255 are exposed to the aqueous environment of the pore when the channel is open. The location and extent of this site can explain why small alcohols occupy the nAChR pore at the same time as larger alcohols or charged blockers, while two large alcohols bind in a mutually exclusive manner.

Amino Acids↗

PubMed2000

Rapid induction of histone hyperacetylation and cellular differentiation in human breast tumor cell lines following degradation of histone deacetylase-1.

Quinidine inhibits proliferation and promotes cellular differentiation in human breast tumor epithelial cells. Previously we showed quinidine arrested MCF-7 cells in G(1) phase of the cell cycle and led to a G(1) to G(0) transition followed by apoptotic cell death. The present experiments demonstrated that MCF-7, MCF-7ras, T47D, MDA-MB-231, and MDA-MB-435 cells transiently differentiate before undergoing apoptosis in response to quinidine. The cells accumulated lipid droplets, and the cytokeratin 18 cytoskeleton was reorganized. Hyperacetylated histone H4 appeared within 2 h of the addition of quinidine to the medium, and levels were maximal by 24 h. Quinidine-treated MCF-7 cells showed elevated p21(WAF1), hypophosphorylation and suppression of retinoblastoma protein, and down-regulation of cyclin D1, similar to the cell cycle response observed with cells induced to differentiate by histone deacetylase inhibitors, trichostatin A, and trapoxin. Quinidine did not show evidence for direct inhibition of histone deacetylase enzymatic activity in vitro. HDAC1 was undetectable in MCF-7 cells 30 min after addition of quinidine to the growth medium. The proteasome inhibitors MG-132 and lactacystin completely protected HDAC1 from the action of quinidine. We conclude that quinidine is a breast tumor cell differentiating agent that causes the loss of HDAC1 via a proteasomal sensitive mechanism.

Acetylation↗

PubMed2000

Stable SNARE complex prior to evoked synaptic vesicle fusion revealed by fluorescence resonance energy transfer.

Although it is clear that soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) complex plays an essential role in synaptic vesicle fusion, the dynamics of SNARE assembly during vesicle fusion remain to be determined. In this report, we employ fluorescence resonance energy transfer technique to study the formation of SNARE complexes. Donor/acceptor pair variants of green fluorescent protein (GFP), cyan fluorescent protein (CFP), and yellow fluorescent protein (YFP) are fused with the N termini of SNAP-25 and synaptobrevin, respectively. In vitro assembly of SNARE core complex in the presence of syntaxin shows strong fluorescence resonance energy transfer (FRET) between the CFP-SNAP-25 and YFP-synaptobrevin. Under the same conditions, CFP fused to the C terminus of SNAP-25, and YFP- synaptobrevin have no FRET. Adenovirus-mediated gene transfer is used to express the fusion proteins in PC12 cells and cultured rat cerebellar granule cells. Strong FRET is associated with neurite membranes and vesicular structures in PC12 cells co-expressing CFP-SNAP-25 and YFP-synaptobrevin. In cultured rat cerebellar granule cells, FRET between CFP-SNAP-25 and YFP-synaptobrevin is mostly associated with sites presumed to be synaptic junctions. Neurosecretion in PC12 cells initiated by KCl depolarization leads to an increase in the extent of FRET. These results demonstrate that significant amounts of stable SNARE complex exist prior to evoked synaptic vesicle fusion and that the assembly of SNARE complex occurs during vesicle docking/priming stage. Moreover, it demonstrates that FRET can be used as an effective tool for investigating dynamic SNARE interactions during synaptic vesicle fusion.

Animals↗

PubMed2000

Intracerebroventricular injection of the N-terminal substance P fragment SP(1-7) regulates the expression of the N-methyl-D-aspartate receptor NR1, NR2A and NR2B subunit mRNAs in the rat brain.

Studies have implicated substance P (SP) in the regulation of affective behaviour, memory function, pain influx, stress and opioid reward. All these dimensions are known to involve glutamate transmission mediated through the N-methyl-D-aspartate (NMDA) receptor. The SP N-terminal fragment SP(1-7) is shown to share some but oppose other effects of the parent compound. We have examined the effect of intracerebroventricular injections of SP(1-7) on the expression of the NMDA receptor subunits NR1, NR2A and NR2B mRNAs in the spinal cord and in discrete areas of the male rat brain. The results indicated that the heptapeptide induced a dose-dependent upregulation of the NR2A transcript in hippocampus, periaqueductal grey and ventral tegmental area, already within a few hours. The level of the NR2B mRNA was increased in hippocampus and nucleus accumbens. The expression of the transcript of the NR1 was enhanced in hippocampus and nucleus accumbens but attenuated in spinal cord. The observed effects of the SP(1-7) fragment are in agreement with what could be expected from the known effects of the heptapeptide on various behaviours involving glutamate transmission.

Animals↗

PubMed2000

Structural relatedness of distinct determinants recognized by monoclonal antibody TP25.99 on beta 2-microglobulin-associated and beta 2-microglobulin-free HLA class I heavy chains.

The association of HLA class I heavy chains with beta2-microglobulin (beta2m) changes their antigenic profile. As a result, Abs react with either beta2m-free or beta2m-associated HLA class I heavy chains. An exception to this rule is the mAb TP25.99, which reacts with both beta2m-associated and beta2m-free HLA class I heavy chains. The reactivity with beta2m-associated HLA class I heavy chains is mediated by a conformational determinant expressed on all HLA-A, -B, and -C Ags. This determinant has been mapped to amino acid residues 194-198 in the alpha3 domain. The reactivity with beta2m-free HLA class I heavy chains is mediated by a linear determinant expressed on all HLA-B Ags except the HLA-B73 allospecificity and on <50% of HLA-A allospecificities. The latter determinant has been mapped to amino acid residues 239-242, 245, and 246 in the alpha3 domain. The conformational and the linear determinants share several structural features, but have no homology in their amino acid sequence. mAb TP25.99 represents the first example of a mAb recognizing two distinct and spatially distant determinants on a protein. The structural homology of a linear and a conformational determinant on an antigenic entity provides a molecular mechanism for the sharing of specificity by B and TCRs.

Amino Acid Sequence↗

PubMed2000

Syntheses and characterization of anti-inflammatory dinuclear and mononuclear zinc indomethacin complexes. Crystal structures of [Zn2(indomethacin)4(L)2] (L = N,N-dimethylacetamide, pyridine, 1-methyl-2-pyrrolidinone) and [Zn(indomethacin)2(L1)2] (L1 = ethanol, methanol).

The syntheses and spectral and structural characterizations of Zn(II) indomethacin [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid = IndoH] complexes, as different solvent adducts, have been studied. The complexes are unusual in that both monomeric and dimeric complexes are formed and that this is the first example of the same carboxylato ligand binding via both carboxylate oxygen atoms in monomeric and dimeric Zn(II) complexes. The crystal structures of Zn-Indo complexes with N,N-dimethylacetamide (DMA), pyridine (Py), 1-methyl-2-pyrrolidinone (NMP), EtOH, and MeOH as solvent ligands, [Zn2(Indo)4(DMA)2].2DMA, 1, [Zn2(Indo)4(Py)2].2H2O, 2b, [Zn2(Indo)4(NMP)2], 3, cis-[Zn(Indo)2(EtOH)2], 4, and cis-[Zn(Indo)2(MeOH)2], 5, were determined. Complexes 1, 2b, and 3 crystallize in the triclinic space group P1 (No. 2): a = 13.628(2) A, b = 17.462(2) A, c = 11.078(1) A, alpha = 99.49(1) degrees, beta = 108.13(1) degrees, gamma = 110.10(1) degrees for 1; a = 13.347(3) A, b = 16.499(5) A, c = 10.857(1) A, alpha = 99.48(2) degrees, beta = 108.25(2) degrees, gamma = 106.24(2) degrees for 2; a = 14.143(3) A, b = 14.521(2) A, c = 11.558(2) A, alpha = 109.07(1) degrees, beta = 90.80(2) degrees, gamma = 116.40(1) degrees for 3. The three complexes exhibit dinuclear paddle-wheel structures with a Zn...Zn distance of 2.9686(6) A, Zn-ORCOO distances of 2.035(2)-2.060(2) A, and a Zn-ODMA distance of 1.989(2) A in 1, a Zn...Zn distance of 2.969(1) A, Zn-ORCOO distances of 2.020(3)-2.049(3) A, and a Zn-NPy distance of 2.036(3) A in 2, and a Zn...Zn distance of 2.934(1) A, Zn-ORCOO distances of 2.009(3)-2.051(3) A, and a Zn-ONMP distance of 1.986(3) A in 3. In these cases, the zinc ions are offset along the z direction such that the L-Zn...Zn-L moiety is nonlinear, unlike the Cu analogues. Each Zn has a square-pyramidal geometry bridged by four carboxylato ligands in the basal plane with the solvent ligands containing an O- or N-donor atom at the apex. Complexes 4 and 5 are isostructural, with space group C2/c (No. 15). For 4, a = 30.080(2) A, b = 5.3638(6) A, c = 24.739(2) A, beta = 90.342(7) degrees, and for 5, a = 29.419(2) A, b = 5.320(2) A, c = 24.461(2) A, beta = 90.840(4) degrees. The Zn resides on a 2-fold axis and the complexes have a distorted cis octahedral structure with Zn-ORCOO bond lengths of 2.183(3) and 2.169(3) A, a Zn-OEtOH bond length of 2.015(3) A in 4, Zn-ORCOO bond lengths of 2.195(2) and 2.151(2) A, and a Zn-OMeOH bond length of 2.022(3) A in 5.

Anti-Inflammatory Agents↗