Application of the Electrotopological State Index to QSAR Analysis of Flavone Derivatives as HIV-1 Integrase Inhibitors

Purpose. A QSAR study based on electrotopological state (E-state) indices was conducted for a series of flavone HIV-1 integrase inhibitors to guide drug design. Methods. E-state indices formulated to encode electronic and topological information for each skeletal atom in a molecule (Kier and Hall Pharm. Res. 7:801–807 (1990)) were calculated using the Molconn-X program, and partial least squares (PLS) multivariate regression was used to derive QSAR models. Results. Predictive models with correlation coefficients (r²) of 0.98 (3 PLS components) and 0.99 (5 PLS components) and corresponding cross-validated correlation coefficients (c.v. r²) of 0.51 and 0.73, were obtained for inhibition of cleavage and integration, respectively, with one molecule omitted from the analysis. Conclusions. E-state indices at C6, C3, C5, C5, and O4 were found to be more important for prediction of activity than those for any of the other 12 flavone skeletal atoms that are common to the molecules in the data set.     

The mechanism of directional coronary atherectomy

An attempt was made to assess the mechanism of directional coronaryatherectomy using different methods of analysis. Quantitativecoronary angiography was used as the gold standard to assessthe immediate results of atherectomy, and a comparative quantitativeanalysis of atherectomy and balloon angioplasty was made. Todetermine whether the post-atherectomy cross-sectional areais close to a circle, we compared the area measurements obtainedby edge detection with those obtained by videodensitometry.Finally, the extent of a ‘Dotter’ effect was establishedby quantitative angiography following crossing the stenosiswith the atherectomy device. For the purpose of this study,the results of the first 113 successful atherectomy procedureswere reviewed. In matched lesions, directional atherectomy induceda greater increase in minimal luminal diameter than balloonangioplasty (1.6 mm vs 0.8 mm; P < 0.0001 However, this luminalimprovement is due to a substantial ‘Dotter’ effectinduced by the bulky atherectomy device. Following atherectomy,only a slight difference in cross-sectional area measurementsbetween edge detection and videodensitometry (mean difference:0.28 mm² was found. Histologic examination of an atherectomizedcoronary artery showed a near-circular post atherectomy areageometry. In conclusion, directional atherectomy is a very effectivedevice with a substantially better initial result than balloonangioplasty. However, insertion of this bulky device itselfcauses an important ‘Dotter’effect.     

Contributions of chronological age,age at menarche and menopaus and of anthropometric parameters to axial and peripheral bone densities

Bone mineral density (BMD) was measured in 128 normal postmenopausal women at different skeletal sites: lumbar spine and proximal femur, using dual-energy X-ray absorptiometry (DXA), and the cancellous and cortical envelopes of the distal third of radius and tibia, using precise low-dose quantitative computed tomography (QCT). Multivariate analysis included chronological age, ages related to menstrual history (menopause and menarche) and anthropometric factors, e.g. height and weight, as independent predictive variables. Weight is a much-studied predictor of bone density. At sites of high bone turnover, i.e. cancellous envelope, the effect of weight appeared overshadowed by estrogen-related parameters: age-past-menopause was the first predictor of BMD in the cancellous compartment of radius and in Ward's triangle, and the number of reproductive years was the strongest predictor of BMD in the cancellous compartment of tibia and in the spine (L2–4). This suggests that in addition to menopause, the length of menstrual life should be considered as an explanation for the variations in current bone mass in postmenopausal women.At the cortical level of radius, the effect of chronological age was predominant. At the cortical level of tibia, height and weight were the best predictors of BMD.We conclude that the influence of parameters related to menstrual history is predominant in sites with mainly cancellous tissue and that anthropometric factors constitute the best predictors of BMD in the cortical sites of weight-bearing bones.     

Autoradiographic study of iron-binding sites in the rat brain: distribution and relationship to aging

Specific binding of 59Fe to various brain structures was investigated in rats using nanomolar concentrations of 59FeCl3 and quantitative autoradiography. Saturation studies revealed high affinity binding (kd in the nanomolar range) with binding sites density (Bmax) which varied in different brain regions from 462 fmol per mg tissue in the central thalamic nuclei to over 4 pmol per mg tissue in the cerebral peduncle. Binding was seen in both white and gray matter structures. Bmax values for frontal cortex, dentate gyrus, and substantia nigra were significantly lower in older rats. The distribution of 59Fe binding sites was not consistent with the distribution of brain iron as reported by other investigators. 59Fe binding was reduced significantly in the presence of free radicals. These observations suggest that high affinity binding sites for iron are localized differentially in various brain structures and may play an important role in the translocation and storage of potentially harmful ferric cations in brain. The finding that the capacity of the brain tissue to bind iron diminished with age in discrete brain regions suggests that in the aged animal, the removal of "free" iron from the cellular domain may be impaired in such regions, leading to increased susceptibility to iron-enhanced lipid peroxidation and cell death.     

Influence of age and of desmotropic drugs on the step phenomenon observed in rat skin

Summary Comprehensive analysis of the mechanical properties of rat skin revealed the step phenomenon. This particular observation was made after constant strain rate (analysis of stress strain curves) as well as after constant load (creep experiments). Relative low extensions or low loads were necessary to provoke the steps. In most cases two, sometimes three steps were observed. The step phenomenon was found mainly in skin strips punched out perpendicularly to the body axis. Probably some bonds in the fibrous network are broken giving way to additional elongation whereafter stronger links take over the stress. Since earlier studies demonstrated a pronounced influence of age and of desmotropic drugs on mechanical properties at ultimate load, e.g., tensile strength, ultimate modulus of elasticity, and ultimate strain, also the step phenomenon was studied under these conditions. In stress-strain experiments most of the steps were found at the ages of 2 and 4 months. Total stress loss and total work loss due to the steps were the highest at the age of 4 months. If, however, these values were calculated as percentage of ultimate values, the highest figures were found in young animals. Elongation gain due to the steps also showed a maximum at time of maturation, e.g., 4 months. Similar findings were achieved in creep experiments at medium load (200 g). After treatment with prednisolone acetate more steps and after treatment with d-penicillamine fewer steps were observed. In stress-strain experiments total stress loss and total work loss due to steps were more than twice as high than controls after prednisolone treatment and only one half after d-penicillamine. If calculated as percentage of ultimate stress or percentage of work input, these changes disappeared because of similar changes at ultimate load. However, elongation gain due to steps, which was not significantly influenced by prednisolone acetate but significantly decreased by d-penicillamine, showed the same changes when calculated as percentage of ultimate strain. Under all conditions the step phenomenon mainly influenced the extension parameters. The data presented here confirm earlier observations that mechanical properties at low loads or low and medium extensions show at least to some extent a different pattern under the influence of maturation and age and after treatment with desmotropic drugs compared to the mechanical parameters at ultimate load.     

Effect ofβ-adrenergic blockade on haemodynamic responses to dynamic and isometric exercise in angina pectoris

Summary The effect of treatment for 1–4 weeks with metoprolol, a ₁-selective blocking agent, or alprenolol, on the heart rate and blood pressure response to isometric exercise was studied in two groups of 12 patients with angina. Measurements were made during the peak effect of metoprolol 10, 40 or 50 mg, and alprenolol 200 mg as Aptin^® Durules^®. After 1 min of sustained handgrip at 50% of maximal voluntary contraction, systolic (6–15%) and diastolic (8–12%) blood pressure after both drugs was significantly lower than without any -blockade; Heart rate was decreased by 19–22% by metoprolol but not by alprenolol. The blood pressurerise during handgrip was not attenuated by either drug. The rise in heart rate was significantly reduced (by 36–50%) by metoprolol 40 and 50 mg and alprenolol 200 mg. No patient experienced angina during handgrip. In contrast, all but one were restricted by angina during bicycle exercise without treatment, at a level that produced the same increase in heart rate as the handgrip test, viz. 3 min at a load of 33 W). The cardiovascular response to sustained handgrip is too small to provide a useful challenge for determination of the anti-anginal efficacy of drugs. However, slight ECG changes of ischaemia did occur during handgrip, which were reversed by -blockade.     

麻黄中生物碱类有效成分的非水毛细管电泳含量测定

目的 利用非水毛细管电泳(NACE)法对麻黄中各生物碱类有效成分进行含量测定，并比较不同提取方法中各组份含量差异。方法 采用50mmol／L醋酸铵的甲醇溶液，未加入任何其他添加剂，检测波长为210nm。结果 各组份在8min内达基线分离。伪麻黄碱在9．8～147．0μg／mL，去甲基麻黄碱在6．8～102．0μg／mL，麻黄碱在9．4～141．0μg／mL，去甲基伪麻黄碱在4．8～72．0μg／mL，甲基麻黄碱在6．8～102．0μg／mL分别有良好的线性关系。各麻黄碱类回收率在95．0％～100．4％。结论 为麻黄中各生物碱类有效成分的含量测定提供了一种快速、准确和灵敏的测定方法。     

反相高效液相色谱法测定发酵液中梅岭霉素

目的:建立了发酵液中梅岭霉素的定量测定方法。方法:反相高效液相色谱法,Hypersil-C_(18)柱(4 mm×125mm,5μm),流动相为乙腈-水(78:22),流速1.2mL·min~(-1),检测波长238 nm,室温测定。结果:在1O.2～163.2μg·mL~(-1)范围内梅岭霉素浓度与峰面积呈良好线性关系,r=0.999 7,回归方程为Y=25.44X+2.72。样品的日间 RSD≤1.8％,高中低浓度样品的日内RSD≤2.5％(n=8)。平均回收率为96.9％(n=8,RSD<3.0％)。结论:本方法快速、准确、简便、稳定,为定量分析提供了可靠的依据。