[Clinical efficacy of entecavir combined with Biejiajian pills and its influence on TCM syndrome scores during the treatment of chronic hepatitis B with hepatic fibrosis and blood stasis syndrome].

Objective: To investigate the clinical efficacy of entecavir combined with Biejiajian pills and its influence on TCM syndrome scores during the treatment of chronic hepatitis B with hepatic fibrosis and blood stasis syndrome by prospective, randomized and controlled study. Methods: Patients with chronic hepatitis B with hepatic fibrosis and blood stasis syndrome were selected as the research subjects and randomly divided into a treatment group and a control group. Entecavir plus Biejiajian pills or entecavir plus a simulant of Biejiajian pills were given for 48 weeks. The changes in liver stiffness measurement (LSM) and TCM syndrome scores before and after treatment were compared between the two groups to analyze the correlation. The data between groups were analyzed by t-test/Wilcoxon rank sum test or χ(2) test. Pearson correlation coefficient was used to analyze the correlation between TCM syndrome scores and LSM values. Results: After 48 weeks of treatment, the LSM values of the two groups were significantly lower than those of the baseline (P < 0.001), liver fibrosis was significantly improved, and the LSM values of the treatment group were lower than those of the control group [(8.67 ± 4.60) kPa and (10.13 ± 4.43) kPa, t = -2.011, P = 0.049]. After 48 weeks of treatment, the TCM syndrome scores of the two groups were significantly reduced compared with the baseline (P < 0.001), and the clinical symptoms were significantly relieved, and the total effective rates of the improvement of the TCM syndrome scores in the two groups were 74.19% and 72.97%, respectively, but the differences between the groups were not statistically significant (χ(2) = 0.013, P = 0.910). Correlation analysis showed that there was no obvious trend between TCM syndrome scores and LSM values. There were no serious adverse reactions associated with the drug during the observation period of this study. Conclusion: Based on antiviral treatment with entecavir, regardless of whether it is combined with the Biejiajian pill, it can effectively reduce the LSM value, improve liver fibrosis, reduce TCM syndrome scores, and alleviate symptoms in patients with chronic hepatitis B with liver fibrosis and blood stasis syndrome. Compared with entecavir alone, the combined Biejia pill has greater efficacy in improving liver fibrosis and a favorable safety profile, meriting its implementation and widespread application.

[HRCT features differentiate synchronous multiple primary lung adenocarcinomas from intrapulmonary metastases].

Objective: To investigate the high resolution CT (HRCT) features of lung adenocarcinoma for differentiating synchronous multiple lung adenocarcinoma from lung adenocarcinoma with intrapulmonary metastasis. Methods: The clinical and imaging features of 131 lesions from 62 patients of synchronous multiple primary lung adenocarcinoma (primary group) and 67 lesions from 31 patients of lung adenocarcinoma with intrapulmonary metastases (metastasis group) were retrospectively analyzed. According to the types of lesion, including pure ground glass nodule (pGGN), mixed ground glass nodule (mGGN) and solid nodule (SN), the image feature matching types of patients were divided into 7 types. The differences of image feature matching types between the primary group and the metastasis group were compared. Multiple lesions in the lung of patients were classified into the main lesion and the concomitant lesions according to their size. The differences including the size of the main lesion and the concomitant lesion (long diameter of nodule, long diameter of solid component in nodule), whether it contains ground glass components in nodule, shape, lobulation, margin, spiculation, bubble-like lucency, pleural retraction and pleural attachment were recorded and analyzed. The differences of image features of main lesion and the concomitant lesion in the primary group and the metastasis group were compared. Results: The image feature matching types of pGGN + mGGN and mGGN + mGGN were more common in the primary group, and the ground glass component contained pGGN or mGGN was accounted for 62.9%(39/62). At least one lesion containing the ground glass component was accounted for 96.8% (60/62). There were two types in metastatic groups, mGGN+ SN and SN+ SN accounting for 6.5% (2/31) and 93.5% (29/31), respectively. There were significant differences in image feature matching types between the primary group and metastatic group (P<0.01). Univariate analysis of the main lesions between the two groups showed that the gender, smoking history, long diameter of the main lesion, long diameter of the solid component, the ground glass component and pleural attachment were statistically different (P<0.05). Further analysis by multivariate logistic regression showed that the male (OR=5.742, P=0.010), SN (OR=41.291, P<0.01) and pleural attachment (OR=9.288, P=0.001) were the three significant risk factors associated with the main lesions in metastasis group.The most common concomitant lesions in primary group were pGGN, containing the ground glass component. However, all of the concomitant lesions in the metastatic group were SN (P<0.01), showing round lesions with well-defined margin, attaching the pleura (P<0.05). Conclusions: The HRCT features of lung adenocarcinoma can differentiate synchronous multiple lung adenocarcinoma from lung adenocarcinoma with intrapulmonary metastasis. At least one lesion contains ground glass components (pGGN or mGGN) in synchronous multiple primary lung adenocarcinoma, while SN is more common in lung adenocarcinoma with lung metastasis. Lung cancer with intrapulmonary metastasis can be considered when the main lesion is SN with pleural attachment and the intrapulmonary accompanying lesion is also solid nodules without lobular, speculation and bubble-like lucency.

[Clinical features of long segmental myelopathy caused by nitrous oxide].

OBJECTIVE: To analyze the clinical and imaging characteristics of the neurological damage caused by nitrous oxide (N2O). METHODS: In the study, 10 patients in the Department of Neurology of China-Japan Friendship Hospital from October 2015 to February 2018 were retrospectively analyzed for the demographic data, the history of inhaled N2O, clinical features, blood examination, electrophysiological examination, spinal magnetic resonance imaging and therapeutic efficacy profiles. RESULTS: The male-to-female ratio was 4:6 and it presented with an age-of-onset 17-26 years [the average age: (20.80±3.12) years]. The time from inhaled N2O to onset was 1 month to 1 year [the average time: (6.95±4.19) months]. Paralysis in all the patients and numbness in 9 patients were the main clinical features, while positive Lhermitte's sign in 3 patients, urinary and defecation disturbance in 4 patients were also found. Blood examination indicated anemia in 2 patients, giant cell anemia in 1 case and small cell hypochromic anemia in 1 case. 3 cases had been treated with vitamin B12 in an external hospital, and the other 7 cases had abnormal increase in homocysteine levels. Electrophysiological examinations showed sensory and motor nerve involvement in 9 patients, and motor nerve involvement in 1 patient. The severity of lower extremity lesion was significantly heavier than that of upper extremity. Spinal magnetic resonance imagings showed that long segmental lesions were present in the cervical spinal cord of all the patients, 3 cases with long segmental lesions of the thoracic cord and 2 cases with spinal cord swelling. In 6 cases, the horizontal axis had an "inverted V-type" T2 high signal, 1 case was classified as "crescent", and 3 cases were "eight-shaped". The symptoms in these 10 cases were alleviated in varying degrees after stopping the inhalation of nitrous oxide, actively supplementing high doses of vitamin B12 and doing early rehabilitation exercises. CONCLUSION: Myelopathy with nitrous oxide presents as paralysis and numbness in limb extremities. In imaging, cervical spinal cord damage is common, accompanied by thoracic spinal cord damage. The horizontal axis is more common in the "inverted V-type". Treatment with high doses of vitamin B12 is effective.

[Analysis on the performance evaluation of the Global Fund Malaria Programme in China from 2003 to 2013].

Objective: To analyze the performance of the 5 Global Fund Malaria Programmes in China from 2003 to 2013. Methods: All of the proposals, summaries, progress reports, survey reports, Monitoring& Evaluation reports, and performance rating reports of the 5 Global Fund Malaria Programmes in China and the epidemic data of program areas were collected for statistical analysis from 2012 to 2014. Symposiums were held with relevant experts from national and provincial Centers for Disease Control and Prevention, program managers and staffs from national and provincial Global Fund Malaria Programme offices. The completion of the relevant programme indicators (including the general grant information such as program areas, beneficiaries and funding; the implementation of malaria control measures; the performance of malaria control measures; the malaria incidence in the program areas; the prevalence of malaria parasites; and program management and performance evaluation) were analyzed, and the results: of the symposiums were summarized. Results The implementation period of the 5 Global Fund Malaria Programs were as follows: Round 1 from 2003 to 2008, Round 5 from 2006 to 2010, Round 6 from 2007 to 2012, Round 10 from 2012 to 2013, and National Strategy Application (NSA) from 2010 to 2012. Under the support of all the Global Fund Malaria Programs, a total of 11 936 726 fever cases received microscopic tests, 1 485 915 confirmed and suspected malaria cases were treated, 1 579 773 Long Lasting Insecticide-treated Nets were distributed, 3 414 633 regular nets were treated by insecticide, 40 298 284 primary and middle school students received health education on malaria control. Compared with the baseline value, the completion rates of each indicator increased after the implementation of the programs. The growth value ranged from 12.83% to 83.11%, among which the biggest growth was the value of the indicator'Percentage of households with at least one LLIN/ITN in target areas', and it increased from 9.2% (baseline value of 2006) to 92.31% (value of 2012). The malaria incidence in program areas has dropped significantly year by year, the annual reported malaria incidence in Yunnan and Hainan provinces decreased from 1 950/100 000, 3 850/100 000 in 2002 to 3.31/100 000, 0.15/100 000 in 2012, the P. falciparum malaria incidence in target counties in Hainan province decreased from 90.6/100 000 in 2002 to 0/100 000 in 2012. As from the implementation of NSA grant in 2010 to 2012, the annual reported malaria incidence in 92% of the 75 Type 1 counties was less than 1 per 10 000, 60.00% of Type 1 counties and 98.69% of the 687 Type 2 counties reported zero locally transmitted malaria cases. The Global Fund Secretariat had conducted a total of 37 performance evaluations, of which 9 have been rated as A1, 4 rated as A2, 19 rated as B1 and 5 rated as B1. Conclusions: The Global Fund Malaria Program in China has been closely integrated with the goal and task of National Malaria Control Program, reducing malaria burden in target areas, and pushing Chinese malaria control efforts to move from control to elimination.

Functional polymorphisms in microRNA gene and hepatitis B risk among Asian population: a meta-analysis.

Genetic mutations in microRNA gene can alter expression, which may interact to increase the risk of developing various diseases, including hepatitis B. However, published results are inconclusive or ambiguous. The aim of this review and meta-analysis is to more precisely estimate the association between polymorphisms in microRNA genes and hepatitis B risk. A digital search was performed of the MEDLINE EMBASE, CNKI, and CBM databases to identify relevant articles published up to February 18, 2014. Ten case-control studies were included, with a total of 6042 patients with hepatitis B and 6834 healthy controls. Nine single-nucleotide polymorphisms in the miRNA gene were examined, including miR-34b/c [rs4938723 (T>C)], miR-196a-2 [rs11614913 (C>T)], miR-146a [rs2910164 (G>C)], miR-499 [rs3746444 (T>C)], miR-122 [rs3783553 (ins/del)], miR-149 [rs2292832 (C>T)], miR-106b-25 [rs999885 (A>G)], miR-let-7c [rs6147150 (ins/del)], and miR-218 [rs11134527 (A>G)]. The meta-analysis results indicated that the miR-196a-2*T, miR-122*del, miR-106b-25*A, and miR-let-7c*del alleles/carriers increase the risk of hepatitis B among the Asian population. However, the miR-146a, miR- 499, miR-149, miR-218, and miR-34b/c polymorphisms may not be linked with the risk of hepatitis B. Further investigations are warranted to determine the exact associations between microRNA mutations and hepatitis B susceptibility.

[Application of ARIMA model in predicting the incidence of tuberculosis in China from 2018 to 2019].

Objective: Autoregressive integrated moving average (ARIMA) model was used to predict the incidence of tuberculosis in China from 2018 to 2019, providing references for the prevention and control of pulmonary tuberculosis. Methods: The monthly incidence data of tuberculosis in China were collected from January 2005 to December 2017. R 3.4.4 software was used to establish the ARIMA model, based on the monthly incidence data of tuberculosis from January 2005 to June 2017. Both predicted and actual data from July to December 2017 were compared to verify the effectiveness of this model, and the number of tuberculosis cases in 2018-2019 also predicted. Results: From 2005 to 2017, a total of 13 022 675 cases of tuberculosis were reported, the number of pulmonary tuberculosis patients in 2017 was 33.68% lower than that in 2005, and the seasonal character was obvious, with the incidence in winter and spring was higher than that in other seasons. According to the incidence data from 2005 to 2017, we established the model of ARIMA (0,1,2)(0,1,0)(12). The relative error between the predicted and actual values of July to December 2017 fitted by the model ranged from 1.67% to 6.80%, and the predicted number of patients in 2018 and 2019 were 789 509 and 760 165 respectively. Conclusion: The ARIMA (0, 1, 2)(0, 1, 0)(12) model well predicted the incidence of tuberculosis, thus can be used for short-term prediction and dynamic analysis of tuberculosis in China, with good application value.

[A preliminary study on the molecular characteristics of D-cycloserine resistance of Mycobacterium tuberculosis].

Objective: To investigate the relationship between D-cycloserine resistance and the gene mutations of alrA, ddlA and cycA of Mycobacterium (M.) tuberculosis, as well as the association between D-cycloserine resistance and spoligotyping genotyping. Methods: A total of 145 M. tuberculosis strains were selected from the strain bank. D-cycloserine resistant phenotypes of the strains were determined by the proportion method and the minimal inhibitory concentration was determined by resazurin microtiter assay. PCR amplification and DNA direct sequencing methods were used for the analysis of gene mutations. Relationship between the resistance phenotype and genotype was analyzed by chi-square test. Results: Of the 145 clinically collected strains, 24 (16.6%) of them were D-cycloserine resistant and 121 (83.4%) were sensitive. There were only synonymous mutations noticed on alrA, ddlA and cycA in sensitive strains. Of the 24 D-cycloserine resistant strains, 3 (12.5%) isolates' cycA and 1 (4.2%) isolates' alrA happened to be non-synonymous mutations, in which the codes were 188, 318 and 508 of cycA, and 261 of alrA, respectively. Results on drug sensitivity tests confirmed the minimal inhibitory concentration of the mutant strains were all increased to some degrees. The D-cycloserine resistant rates of 88 Beijing genotype and 57 non-Beijing genotype strains were 20.5% and 10.5% , respectively, but with no statistically significant difference (χ(2) =2.47, P>0.05). Conclusions: The non-synonymous mutations of alrA and cycA might contribute to one of the mechanisms of M. tuberculosis D-cycloserine resistance. M. tuberculosis Beijing genotype or non-Beijing genotype was not considered to be associated with the D-cycloserine resistance.

The clinical implication of theophylline intoxication in the Emergency Department.

We reviewed the clinical manifestations of 53 episodes of theophylline intoxication in 50 patients over a one year study period, in order to identify the specific features as they presented to the Emergency Department (ED). There was a trend to an increase in the serum theophylline concentration with increased severity of clinical features, but the difference between the mild and the moderate cases was not statistically significant. The most common symptoms and signs were gastrointestinal complaints, sinus tachycardia, and atrial arrhythmias. Mixed atrial and ventricular arrhythmias, which are rarely mentioned as a specific feature of theophylline intoxication, were found in 16% of our patients and accounted for 29% of the cardiovascular manifestations. Four patients developed rhabdomyolysis, which presumably was secondary to a seizure or profound hypokalaemia. Cases of theophylline intoxication presenting to the ED had higher serum concentrations of theophylline and tended to have more severe toxicity than those patients in the non-ED group. Delayed diagnosis may contribute to the severity of the outcome, since severe cases in the ED were usually suspected to have developed intoxication at some point later in the stay in the ED than at the time of presentation, or after admission to the hospital, thus permitting the occurrence of an additional iatrogenic component to the intoxication. They also complained of symptoms not associated with the theophylline toxicity, which may have diverted the physician's attention from recognizing this concurrent problem.(ABSTRACT TRUNCATED AT 250 WORDS)

[Structural congeners of guanfu base A and their antiarrhythmic activity].

Guanfu base A (GFA) is an alkaloid isolated from the root of Aconitum coreanum and is effective in several experimental arrhythmia models. GFA can effectively antagonize aconitine-induced arrhythmia, significantly reduce CaCl2-induced incidence of ventricular fibrillation in rats and markedly raise the ventricular fibrillation threshold to electrical stimulation in rabbits and cats. It would be valuable in clinic to treat ventricular fibrillation. Thus, we chose GFA as lead compound for chemical modification. From the view point of stereochemistry, GFA is a rigid structure and can be considered as composed of two layers. The first layer is a hydrogenated phenanthrene ring; the second is the alkylamino chain containing hydroxy and acetoxy groups [formula: see text]. It was speculated that the skeleton of such chain might play as pharmacophore contributing to the biological activity. In order to reduce the size of the molecule and simplify the chemical structure of GFA, the hydrogenated phenanthrene was removed and an aryl residue commonly occurred in the structure of antiarrhythmic agents was introduced. Thus, fourteen derivatives of phenylpropanediolamine were designed and synthesized. There is a hydrogenated indolizine ring in the structure of GFA and a indolizine ring in the structure of class III antiarrhythmic agent--butoprizine. By combing the structural feature of GFA with that of butoprizine, nine indolizine derivatives were also designed and synthesized. Screening test of 23 compounds indicated that phenylpropanediolamine derivatives--I1, I2, I3, I7, I8, I14, and indolizine derivatives--II2 markedly antagonized chloroform-induced arrhythmias in rats. Among them I2, I3, I7 and I8, appeared to be more potent than GFA.

Purification and characterization of an extracellular serine protease from the nematode-trapping fungus Dactylella shizishanna.

AIMS: To evaluate the production of an extracellular serine protease by Dactylella shizishanna and its potential as a pathogenesis factor. METHODS AND RESULTS: An extracellular alkaline serine protease (Ds1) was purified and characterized from the nematode-trapping fungus D. shizishanna using cation-exchange chromatography and hydrophobic interaction chromatography. The molecular mass of the protease was approximately 35 kDa estimated by SDS-PAGE. The optimum activity of Ds1 was at pH 10 and 55 degrees C (over 30 min). The purified protease could degrade purified cuticle of Penagrellus redivivus and a broad range of protein substrates. The purified protease was highly sensitive to phenylmethyl sulfonyl fluoride (PMSF) (0.1 mmol l(-1)), indicating it belonged to the serine protease family. The N-terminal amino acid residues of Ds1 are AEQTDSTWGL and showed a high homology with Aozl and PII, two serine proteases purified from the nematode-trapping fungus Arthrobotrys oligospora. CONCLUSIONS: Nematicidal activity of D. shizishanna was partly related to its ability to produce extracellular serine protease. SIGNIFICANCE AND IMPACT OF THE STUDY: In this report, we purified a new serine protease from D. shizishanna and provided a good foundation for future research on infection mechanism.

Determination of trace selenium in human body by anodic stripping voltammetry at gold-disc electrode.

For determination of trace Se we used high-pressure wet digester to pretreat the specimens obtained from the human body. This method is very effective in preventing loss of Se by volatilization which often occurs in the sample pretreatment. We studied the method of using anodic stripping voltammetry at gold-disc electrode to measure the trace Se present in the human body and found it to be the optimal procedure. The detection limitation was about 2 x 10(-8) g/L, the recovery rate of Se about 96.6 +/- 6.7% (chi +/- s), and the coefficient of variation CV = 7.0%.

Structure-activity relationship: analyses of p-glycoprotein substrates and inhibitors.

OBJECTIVE: A large number of structurally and functionally diverse compounds act as substrates or modulators of p-glycoprotein (p-gp). Some of them possess multiple drug resistance (MDR)-reversing activity, but only a small number of them have entered clinical study. In order to uncover the factors which exert a significant impact on the interaction between substrates/modulators and p-gp, we have performed structure-activity relationship (SAR) analyses, including molecular modelling, two-dimensional (2D) and three-dimensional (3D) parameter-frame-setting analysis, quantitative structure activity relationship (QSAR) analysis among substrates/modulators, as well as clinically promising MDR-reversing agents. METHODS: The physicochemical parameters C log P, CMR and all regression equations were derived by using C log P version 4.0 and the latest CQSAR software, respectively. Molecular modelling and all other parameter calculations were performed by using HyperChem version 5.0 program, after geometry optimization and energy minimization using the AM1 semiempirical method. RESULTS: SAR analyses indicate that MDR reversal activity is correlated with the lipophilicity (C log P), molecular weight (log Mw), longest chain (Nlc) of the molecule and the energy of the highest occupied orbital (Ehomo). In addition, the presence of a basic tertiary nitrogen atom in the structure is also an important contributor to p-gp inhibitory activity. Some separation in space is achieved for different subsets of p-gp substrates and inhibitors using Nlc, C log P and Ehomo as three independent parameters in the 3D-parameter-frame setting. CONCLUSION: A highly effective p-gp modulator candidate should possess a log P value of 2.92 or higher, 18-atom-long or longer molecular axis, and a high Ehomo value, as well as at least one tertiary basic nitrogen atom. The results obtained may be useful in explaining drug-p-gp interactions for different compounds, including drug interactions and the development of new MDR chemosensitizers.

Carbamazepine drug interactions: the influence of concurrent drug therapy on serum concentrations of carbamazepine and its epoxide metabolite.

The influence of concurrent drug therapy (phenytoin, valproate, phenobarbital, primidone) on serum concentrations of total and free carbamazepine (CBZ) and its active metabolite carbamazepine-10, 11-epoxide (CBZ-E) in 135 epileptic patients was studied. Serum CBZ and CBZ-E levels were analyzed by high performance liquid chromatography, whereas serum levels of the anticonvulsants were determined by fluorescence polarization immunoassay. Ultrafiltration was used to separate the free drugs from the protein-bound drugs in serum. Patients were divided into five groups according to the medication they received. Linear regression analyses revealed that concurrent drug therapy affected the metabolic rate of CBZ and CBZ-E in various ways. In patients on CBZ monotherapy, 78.3% of CBZ and 52.4% of CBZ-E were bound to plasma proteins. The total serum CBZ and CBZ-E concentrations significantly correlated with their respective free levels in serum. Compared with the CBZ monotherapy group, patients receiving concurrent drug therapy showed higher CBZ clearance and had elevated CBZ-E/CBZ ratios. Although the decrease in the total CBZ concentration depended on the simultaneous phenytoin and valproate concentrations (p less than 0.05), the serum levels of phenobarbital and primidone appeared to have no significant influence on the CBZ concentration. Since great interindividual variations were found in the serum concentration after a given dose, routine monitoring of the CBZ and CBZ-E serum concentrations is essential in designing a safe and effective therapeutic regimen for epileptic patients, especially for those on polytherapy.

An improved method of direct chromosome preparation from chorionic villus and high resolution banding technique.

The trophoblast was dissociated from the underlying mesenchymal layer either with acetic acid after short-term prefixation or with mechanical power after fixation twice. The colcemid treatment time was shorted to 16 min and trypsin solution of low pH (6.2) was used for banding. By these steps, the quality of chromosome banding was greatly improved and complete standard chromosome diagnoses were made in 24 of 24 cases. With the modified technique, high resolution banding chromosomes were consistently obtained after short-term incubation.

Comparison of nonspecific radioimmunoassay, high-performance liquid chromatography, and fluorescence polarization immunoassay for cyclosporine monitoring in renal transplantation.

Three methods, i.e., nonspecific radioimmunoassay (RIA; Incstar), fluorescence polarization immunoassay (FPIA; TDx Abbott), and high-performance liquid chromatography (HPLC), have been used for monitoring cyclosporine blood levels in renal transplantation patients. The levels obtained from 135 samples showed a modest correlation between RIA and HPLC, FPIA and HPLC, RIA and FRIA. The mean ratios of RIA to HPLC, FPIA to HPLC, and RIA to FPIA were 2.96, 4.14, and 0.73. The significant variations in cyclosporine levels result from the cross-reaction of antibody with some cyclosporine metabolites, by which these two methods often overestimate the true blood cyclosporine level. HPLC is a more effective and reliable method for pharmacokinetic studies and blood level monitoring of cyclosporine in clinical practice.

G-protein coupled receptors: SAR analyses of neurotransmitters and antagonists.

BACKGROUND: From the deductive point of view, neurotransmitter receptors can be divided into categories such as cholinergic (muscarinic, nicotinic), adrenergic (alpha- and beta-), dopaminergic, serotoninergic (5-HT1 approximately 5-HT5), and histaminergic (H1 and H2). Selective agonists and antagonists of each receptor subtype can have specific useful therapeutic applications. For understanding the molecular mechanisms of action, an inductive method of analysis is useful. OBJECTIVE: The aim of the present study is to examine the structure-activity relationships of agents acting on G-protein coupled receptors. METHOD: Representative sets of G-PCR agonists and antagonists were identified from the literature and Medline [P.M. Walsh (2003) Physicians' Desk Reference; M.J. O'Neil (2001) The Merck Index]. The molecular weight (MW), calculated logarithm of octanol/water partition coefficient (C log P) and molar refraction (CMR), dipole moment (DM), E(lumo) (the energy of the lowest unoccupied molecular orbital, a measure of the electron affinity of a molecule and its reactivity as an electrophile), E(homo) (the energy of the highest occupied molecular orbital, related to the ionization potential of a molecule, and its reactivity as a nucleophile), and the total number of hydrogen bonds (H(b)) (donors and receptors), were chosen as molecular descriptors for SAR analyses. RESULTS: The data suggest that not only do neurotransmitters share common structural features but their receptors belong to the same ensemble of G-protein coupled receptor with seven to eight transmembrane domains with their resultant dipoles in an antiparallel configuration. Moreover, the analysis indicates that the receptor exists in a dynamic equilibrium between the closed state and the open state. The energy needed to open the closed state is provided by the hydrolysis of GTP. A composite 3-D parameter frame setting of all the neurotransmitter agonists and antagonists are presented using MW, Hb and mu as independent variables. CONCLUSION: It appears that all neurotransmitters examined in this study operate by a similar mechanism with the G-protein coupled receptors.

Studies on the determination of diacetyl guanfubase A concentration in rabbit plasma and pharmacokinetics.

A gas chromatographic method for monitoring diacetyl guanfubase A in plasma is described. The procedure involved a single solvent extraction of drug from rabbit plasma into ethyl acetate with guanfubase A as an internal standard. The extract was analyzed subsequently on a gas chromatograph equipped with a hydrogen flame ionization detector. The recovery was 86.43% +/- 6.90% (+/- SD); the RSD of within-day and between-day was 2.81%-5.26% and 5.22%-8.24%, respectively; the regression line was linear over the concentration range of 25-200 micrograms/mL, the limit of detection was 10 micrograms/mL. No endogeneous interference was found in chromatograms of the biological samples. This method was applied to the pharmacokinetic study of diacetyl guanfubase A in rabbits.