Comparative QSAR analysis of estrogen receptor ligands.
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Journal Article↗
Biomedical subjects
H Gao
Publications and source records attributed to H Gao.
Determination of neostigmine in human plasma and cerebrospinal fluid by high-performance liquid chromatography with ultraviolet detection.
A high-performance liquid chromatographic assay coupled with ultraviolet detection has been developed for the determination of neostigmine in human plasma and cerebrospinal fluid. A novel solid-phase extraction procedure was first used for this analyte and allowed good recovery (89+/-4.5%) together with ease and speed of execution. The method was sensitive, reproducible (C.V.<4.5%) and accurate (100+/-6.6%) over the range 2.6-167.0 ng/ml neostigmine concentrations in plasma or cerebrospinal fluid, and was applied successfully to study the pharmacokinetics of neostigmine in patients suffering from chronic postoperative abdominal pain.
Cholinesterase Inhibitors↗
Dislocations faster than the speed of sound
It is thought that dislocations cannot surpass the sound barrier at the shear wave velocity because the energy spent in radiation has a singularity there. Atomistic simulations show that dislocations can move faster than the speed of sound if they are created as supersonic dislocations at a strong stress concentration and are subjected to high shear stresses. This behavior is important for the understanding of low-temperature deformation processes such as mechanical twinning and may be relevant for the dynamics of tectonic faults. The motion of the dislocations at a speed of 2 times the shear wave velocity can be understood from a linear elastic analysis, but many of the peculiarities of the supersonic dislocations are dominated by nonlinear effects that require a realistic atomistic description.
Journal Article↗
[Mutations of the fibroblast growth factor receptor 3 gene in achondroplasia].
OBJECTIVE: To evaluate whether mutation in the exon 10 of the fibroblast growth factor receptor 3(FGFR3) gene in common in Chinese patients with achondroplasia. METHODS: Genomic DNA from seven sporadic cases of achondroplasia was studied by using PCR-SSCP and restriction enzymes. RESULTS: All patients carried the same glycine-to-arginine mutation at codon 380(G380R) of the transmembrane domain of FGFR3. CONCLUSION: The results suggest that the G380R mutation of FGFR3 is also a frequent mutation causing achondroplasia in Chinese. Detecting FGFR 3 gene mutation with PCR-SSCP and restriction enzymes analysis is a convenient, rapid and reliable molecular diagnostic assay for prenatal and early diagnosis of achondroplasia.
Achondroplasia↗
Modeling plasticity at the micrometer scale
Plastic deformation exhibits a strong dependence upon size at and below micrometer length scales. To model micrometer scale plasticity we propose a theory called mechanism-based strain gradient plasticity (MSG), which connects microscale dislocation interactions to mesoscale plasticity via a hierarchical framework linking Taylor's dislocation hardening model to strain gradient plasticity. We distinguish the microscale, at which dislocation interaction is considered, from the mesoscale, at which the plasticity theory is formulated. The MSG theory differs from all existing phenomenological theories of plasticity in its mechanism-based guiding principles. We show that the MSG theory gives predictions in agreement with microindentation, microtorsion, and microbending experiments.
Journal Article↗
Effects of IBMX on norepinephrine-induced vasoconstriction in small mesenteric arteries.
The present study assesses the effects of the phosphodiesterase inhibitor IBMX on norepinephrine (NE)-induced constriction of small mesenteric arteries. Arteries ( approximately 150 micrometer) were dissected from rats and mounted on a wire myograph for isometric force measurement. NE concentration effect curves were generated after exposure to 500 microM IBMX for 60 min. IBMX significantly reduced NE-induced tension development. Studies were also conducted following sarcoplasmic reticulum (SR) depletion (ryanodine, 10 microM) or L-type Ca2+ channel blockade [(+)-BAY K 8644, 10 microM] in the presence and absence of IBMX. Both SR depletion and L-channel blockade reduced NE-induced tension generation, consistent with incomplete Ca2+ mobilization. IBMX significantly attenuated NE responses in ryanodine and (+)-BAY K 8644-treated vessels. Finally, treatment of NE-stimulated vessels with IBMX (500 microM) caused a reduction in vascular tension that was greater than the concomitant reduction in cytosolic Ca2+ concentration ([Ca2+]i), indicating that a portion of the IBMX-mediated relaxation is Ca2+-independent. These data suggest that IBMX attenuation of NE responsiveness not only involves a reduction in [Ca2+]i but also a significant decrease in Ca2+ sensitivity.
1-Methyl-3-isobutylxanthine↗
Biochemical parameters, nutritional status and efficiency of dialysis in CAPD and CCPD patients.
BACKGROUND/AIMS: Several studies indicate that small solute transport is influenced by peritoneal dialysate volume and dwell time. This study focuses on the clinical impact of peritoneal dialysis modality, continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD). METHODS: We studied 18 patients on CAPD and 11 on CCPD for 18 months and assessed biochemical parameters, nutritional status and efficiency of dialysis at 6-month intervals. RESULTS: Four-hour D/P urea and creatinine ratios were similar in both CAPD and CCPD patients. However, 24-hour D/P urea and creatinine ratios were significantly higher in CAPD than in CCPD patients (0.9 +/- 0.1 vs. 0.8 +/- 0.2 and 0.8 +/- 0.1 vs. 0.6 +/- 0.2, p < 0.05 and p < 0.01, respectively). The dialysate urea nitrogen concentration was significantly different between the two groups (65 +/- 14 mg/dl in CAPD, 48 +/- 13 mg/dl in CCPD; p < 0.05). Total weekly Kt/V and total weekly creatinine clearance were not significantly different between CAPD and CCPD patients at 18 months (1.6 +/- 0.4 vs. 1.7 +/- 0.3 and 52 +/- 21 vs. 50 +/- 12 liters, respectively). Two-way ANOVA with a post-hoc Bonferroni-Dunn test showed serum potassium concentration was significantly lower in CCPD patients at 18 months (3.8 +/- 0.5 mEq/l, p < 0.05), and significant increases in triglyceride levels in the CAPD groups by 18 months (301 +/- 286 mg/dl, p < 0.05). CONCLUSION: This study demonstrates that the mean serum triglyceride level increases in CAPD patients over time, and the mean serum potassium concentration decreases in CCPD patients at 18 months. Dialysis adequacy and nutritional status are not significantly different between the two peritoneal dialysis modalities, CAPD and CCPD. We suggest the peritoneal dialysis prescription for CAPD or CCPD with respect to volume and frequency of exchanges be individualized to achieve adequate of therapy.
Adult↗
[The combined effect of noise and vibration on intelligibility of Chinese syllables].
Objective. The changes of auditory effect on Chinese single syllables uttered by talker under combined condition of noise and vibration were investigated. Method. The intelligibility tests were made under three conditions (quiet, 0 dB and -6 dB S/N ratios). The utterances were recorded under combined factors of noise and vibration, single factor of noise or vibration, and the control condition. Result. As compared with control group, the decrease of speech intelligibilities in combined factors groups was significant. It also occurred in most cases as compared with the single factors groups. It showed that combined effects played greater roles as S/N decreased in listening environment. As S/N was -6 dB, the intelligibilities were less than 70 percent. Conclusion. The speech production will be changed under noise and vibration, and the changes will deteriorate communication, especially in adverse listening environment. The results have important implications for communication in aerospace and military environments.
Aerospace Medicine↗
[Experience of endoscopic sinus operation on 74 cases].
OBJECTIVE: To improve the curative effect of endoscopic sinus operation. METHOD: The clinical data of nasal cavity and nasal sinus via endoscopic sinus operation on 74 cases (115 sides) were in summary. Of those 74 cases, 65 were followed-up over six mothes. RESULT: It showed that 44 cases were cured, 18 were improved, 3 were ineffective. The effective rate was 95.4%. The disappearance rate of four symptons-nasal obstruction, headache, purulent nasal discharge and loss of smelling was 95.2%, 92%, 66.7% and 42.5%, respectively. The serious operative complication was absent. CONCLUSION: It helped to raise thd effect of anesthetization to apply nasal cavity surface anesthesia, nerve block anesthesia. Paying attention to the distinguish of dissection label can help to decrease the occurance of the serious complication of the sinus ethmoidal operation. The operation which was alternatively conducted between endoscope and cavascope, according to the operation requirement, can be carried out more thoroughly and more safely. Cleaning the operation cavity after operation can promote healing.
Adult↗
[Analysis of the relationship between the facial skin temperature and blood flow].
The relationship between the blood flow of temperal or facial artery and facial skin temperature was studied in 30 patients with facial nerve paralysis. The facial skin temperature was recorded by infrared thermography, and the blood flow was measured by ultrasonic Doppler flowetry. The results showed, in the same facial region, the greater the volume of blood flow was, the higher the skin temperature stood. After acupuncture on the facial points, the facial blood flow increased and the facial skin temperature rose. The ratios between the increase in facial skin temperature and the in increase in blood flow were 0.9538-1.2835(degrees:ml/second) in four facial regions. These indicate the presence of certain quantitative relationship between the facial blood flow and the skin temperature.
Adult↗
[Laryngeal function preserving surgery in hypopharyngeal carcinoma].
OBJECTIVE: To investigate the results of the conservation laryngectomy in patients with hypopharyngeal carcinoma. METHODS: Twenty-three cases with hypopharyngeal carcinoma that were treated with function-sparing laryngectomy during a 15-year period were reviewed retrospectively. RESULTS: The 3-year survival rate was 73.9% (17/23) and 5-year survival rate was 47.8% (11/23). Severe complication occurred in 8 of 23 (34.8%). Complete restoration of laryngeal function was achieved in 20 cases (87%) and deglutition restored in all patients (100%). The mean duration of oral intake was 11.8 days (6-33 days) and mean hospitalization was 32 days (14-94 days). CONCLUSION: Conservation laryngectomy and hypopharyngectomy is not only efficacious in the treatment of hypopharyngeal carcinomas, but also reserves laryngeal function and thus improves the quality of patients life.
Adult↗
[Determination of 2,4-dinitrochlorobenzene in environmental water by primary-secondary wavelengths new spectrophotometry].
In basic solution, dinitrochlorobenzene may react on pyridine to form a purplish red compound. In this paper with the absorption property of a suspended liquid against light a new analytical method as primary-secondary wavelengths spectrophotometry was studied to determine trace dinitrochlorobenzene in environmental water. In 0-50 microg dinitrochlorobenzene/25 mL, the calculation curve is very stable and hardly affected by environment conditions. Experiments for practical waters have shown that the detection limit was 0.7 microg/25 mL dinitrochlorobenzene and RSD < or = 2.7% and the recovery rate was 99.2%-101.0%.
Dinitrochlorobenzene↗
[Determination of copper in waste water by beta-correction new spectrophotometry].
In pH 5-6 solution copper [Cu(II)] can react on p-dimethylaminobenzylidene rodamine (PDR) to form red compound. Beta-correction spectrophotometry was studied to determine trace copper. It can remove the absorption interference of surplus PDR in reaction solution to raise the analytical sensitivity. Experiments for samples showed that RSD = 2.9% and the recovery rate was 87.7%-112%. The minimium concentration of the determination is 0.55 microg/25 mL. The method is suited to analyse copper in metals and waste water.
Copper↗
[Mechanism of gold solvent extraction from alkaline cyanide solution by surfactant 1 427].
The solvent extraction of gold and the structure of the organic phase were studied by labelled 198Au, 31P NMR and FTIR spectroscopy. The results show that the water content increased with the increase of gold contents in the organic phase. The P=O stretching decreases, while the 31P signal shifts to upfield.
English Abstract↗
Quantitative structure-activity relationships (QSAR) for 9-anilinoacridines: a comparative analysis.
A new analysis of the quantitative structure-activity relationship (QSAR) of the antitumor activity of anilinoacridines against L1210 leukemia in mice and mouse toxicity is reported. QSAR have also been derived for the inhibitory activity of the anilinoacridines with tumor cells and their binding to DNA. These results are compared with reactivity with simple nucleophiles. The comparative analysis shows the importance of electron releasing substituents (in general negative coefficients with the Hammett parameter sigma+) throughout the various systems and the complete lack of hydrophobic interactions from DNA to cells to mice. The presence of steric terms suggests that a protein receptor is involved. The study shows that QSAR has an important role to play in improving the efficiency in the design of bioactive compounds and that care must be taken in the design of a set of congeners so that the necessary parameters are available to do the QSAR analysis. Our study illustrates the value of comparative QSAR in generalizing our understanding of chemical-biological interactions.
Amsacrine↗
Determination of succinylcholine in human plasma by high-performance liquid chromatography with electrochemical detection.
An alternative HPLC method for the quantification of the depolarizing neuromuscular blocking agent succinylcholine in human plasma is described. Drug spiked plasma and patient plasma samples were extracted using a C1 solid-phase cartridge. Succinylcholine was separated on a Cyano column and quantitated using electrochemical detection at a potential of 450 mV and 750 mV. Mobile phase consisted of a mixture of phosphoric acid-acetonitrile-methanol (45:35:25) adjusted to an apparent pH of 5. Standard curves for the quantitation were linear in the range of 250-8000 ng/ml. Between-day and within-day relative standard deviations were 5.1% and 1.7%, respectively. Mean drug recovery and accuracy was 68% and 104%, respectively.
Chromatography, High Pressure Liquid↗
Cerebellar brain-derived neurotrophic factor-TrkB defect associated with impairment of eyeblink conditioning in Stargazer mutant mice.
In the spontaneous ataxic mutant mouse stargazer, there is a selective reduction of brain-derived neurotrophic factor (BDNF) mRNA expression in the cerebellum. BDNF protein levels in the cerebellum are reduced by 70%. Despite normal levels of full-length and truncated TrkB receptor, constitutive and neurotrophin-4/5-induced tyrosine phosphorylation was significantly reduced in several signal transduction molecules, including phospholipase-Cgamma1, erk1, and erk2. Morphological examination revealed an increased number of external granule cells at postnatal day 15 and the presence of abnormal neurons resembling immature granule cells in the adult. These abnormalities are associated with a severe impairment in the acquisition of classical eyeblink conditioning, indicating cerebellar malfunction. Our data suggest that normal BDNF expression and TrkB signal transduction in the cerebellum are necessary for learning and plasticity in this model.
Animals↗
Phenol toxicity in leukemia cells: a radical process?
The multiple functions of the phenol moiety that are widely present in disparate sources such as drugs, pesticides, teas, fuel additives and surfactants have not been clearly delineated. The differences in behavior of phenols, which run the gamut from aberrations in DNA/chromosomes to suppression of genotoxic activity of carcinogenic compounds, merit further attention. In this study, a through examination of the growth inhibition patterns of 37, simple 3- and 4-substituted phenols in mouse leukemia cells was carried out and the following quantitative structure-activity relationship (QSAR) was obtained for the 23 electron releasing substituents in X-phenols: log 1/IC50 = -1.58 sigma(+) +0.21 log P + 3.10. In this QSAR, IC50 is the concentration of phenol that induces 50% inhibition of growth. P is a measure of the hydrophobicity of each phenol and Brown's electronic parameter, sigma+, represents the electronic effect of the substituent. The negative dependence on sigma+ is strongly reminiscent of what is observed in the developmental toxicity of phenols on rat embryos as well as for the radical abstraction of a hydrogen atom from phenolic groups. The other 15 electron-attracting substituted X-phenols clearly show a linear dependence on hydrophobicity alone: Log 1/IC50 = 0.62 log P + 2.35. The bifurcation in mechanism of action of this large set of diverse phenols is novel and unusual. It suggests that two distinct processes are operative. In the case of electron releasing substituted phenols, the observations are not inconsistent with a radical mediated process while with electron attracting substituted phenols, non-specific toxicity as modulated by hydrophobicity, appears to predominate.
Animals↗