Quantitative succinate-dehydrogenase histochemistry. I. A Methodological study on mammalian and fish muscle.

In enzyme histochemistry formazan production can be used as a measure for oxidative enzyme activity. The formazan deposits can be measured quantitatively per cell with a scanning and integrating microspectrophotometer. Optimal conditions are described for the estimation of histochemical succinate dehydrogenase activity in sections of fish bodymusculature and mouse soleus and plantaris muscle. It is shown that when proper measuring conditions are chosen a ditetrazolium salt (TNBT) can be used in quantitative enzyme histochemistry and that the optimal conditions for the histochemical succinate dehydrogenase reaction in muscle fibres of fish and mouse muscle are somewhat different for these two species. The differences in pH, temperature and succinate sensitivity are the most prominent.     

基于熵理论的城市生态系统服务流定量评估——以北京市为例

量化评价生态系统的服务功能是合理开发生态资源、实现可持续发展的重要前提.生态系统服务流能够为生态系统服务功能的量化评估提供解决方案.本文以四大生态系统服务类型为框架,构建了城市生态系统服务流评估体系;将生态系统服务流重新分类,引入熵理论,对指标及系统无序度、发展演变方向进行定量评价;并以北京市为研究对象,选择24个因子开展案例研究.结果表明:2004—2015年间,北京城市生态系统服务总熵值为0.794,总熵流为-0.024,系统无序度较大,濒临非健康状态;系统熵值3次取得极值,3个变化周期内系统熵值的年平均变化幅度逐渐增大,说明人为活动对城市生态系统干预强度增大;2007年熵流达到最小值,生态环境质量最高;北京市常住人口总数与城市生态系统熵流拟合函数的决定系数为0.921,说明人口数量与城市生态环境状态有很强的相关性.     

Quantitative study of secondary structure of histones H1, H2A, and H4 in solution by infrared spectroscopy.

The secondary structure of histones H1, H2A, and H4 (F1, F2a2, and F2a1) has been quantitatively studied in heavy water (2H2O) solutions in a wide range of histone concentration, p2H, and concentration of sodium chloride using an improved infrared spectroscopy method. Under all conditions there are about 5--10% of alpha helix. Conditions favourable for aggregation induce formation of antiparallel pleated sheet structure to an extent of about 15% in H1 and H2A and about 30% in H4. When the p2H and concentration of NaCl are in the physiological range, there is the same content of this structure in H2A and H4 and none in H1.     

A Quantitative study of histamine H2-receptor bockade by burimamide in isolated artica.

The onset of burimamide inhibition of histamine stimulation of rabbit atria is rapid, and a near steady-state blockade occurs at approximately 15 min ( larger than or equal to 90% complete). The blockade is reversible but requires several washings suggesting the disassociation is slow. The administration of histamine may accelerate the decay of the burimamide effect. Reciprocal plots (rate response versus histamine concentration) of dose-response curves are linear for both rabbit and guinea pig atria. In the presence of low concentrations of burimamide; (2.4 times 10-5 M), the displacement of curves suggests a competitive type of inhibition both for rabbit and guinea guinea pig atria. The apparent association constants calculated from these curves are: K1 (rabbit) 3.7 times 10-6M and K-1 (guinea pig) 6.7 times 10-6M. These results for guinea pig atria are in satisfactory agreement with the value obtained in another laboratory (2). At higher concentrations of burimamide, inhibition curves showed distinct evidence of departure from competitive character for both guinea pig and rabbit atria.     

Quantitative analyses of morphological changes of cell growth by graphics computer techniques. A methodologic study

A computerized image analysis system is described for quantitation of changes in cell morphology for use in the bioassay of certain types of growth factors in organ cultures of connective tissue cells.Eight response variables, indicative of cell growth, were measured (area of cell, area of nucleus, area of cytoplasm, length of the cell, lengths of the major and minor axes, number of nucleoli per cell, and total area of nucleoli per cell).Principal components analyses were used to eliminate redundant variables and to estimate the dimensionality of the problem. In general, only four response variables were required in order to describe the morphological changes occurring during cell growth of these connective tissue fibroblasts. Some sacrifice in independence of variables was tolerated in order to compensate for some shifts in correlations between some variables at different doses of growth factor. Cell length and area of the cell provided the best quantitative measures for distinguishing between doses of growth factors and for correct ranking of doses.     

Quantitative and thermodynamic study of weak A erythrocyte phenotypes]

The analysis of more than 140 "weak A" samples: A3, Ax, Aend, Am, Ay and Ael, support the classical distinction between each subgroup which has been established on serological and genetical data. Accordingly, a valuable classification of these rare phenotypes must take into account, (i) the mode of inheritance, (ii) the agglutination pattern of the RBC by anti-A reagents, (iii) the presence or absence of soluble A substances in the saliva of secretors. The question is then open to know if such related erythrocytic antigens, whose specificity appears to be very similar, could be described on a quantitative basis or on qualitative structural variations. Evidence for quantitative differences was first demonstrated by a gradual decrease in the standard agglutinability of "weak A" RBC with human anti-A (B) sera, from A3 red cells (63 +/- 10%) to Ax (33 +/- 10%), Aend (10 +/- 5%) then Am, Ay and Ael (0%), and secondly by direct measurement of A antigen site densities, the mean values being respectively 35.10(3) A sites/RBC (A3); 4.8 10(3) (Ax); 3.5 10(3) (Aend) and 0.7 10(3) (Am, Ael). Further investigation on A3, Ax and Aend RBC agglutinability lead also to the demonstration of a large heterogeneity in the A antigenic content of red cells inside one individual sample. The most striking result was obtained with Aend phenotypes which appeared like A + O transmitted mosaicisms. However, heterogeneity was also observed, but to a lesser extent, among A3 and Ax RBC. The significance of this heterogeneity is discussed and used to explained the typical picture of agglutinability commonly observed with such red cells and anti-A antibodies. Qualitative difference were also studied by estimation of equilibrium constants (Ko) and thermodynamic parameters (delta Fo, delta Ho and delta So) associated with the binding of rabbit 125I-IgG anti-A molecules onto A RBC determinants. Only small variations of thermodynamic parameters were observed between each subgroup, but the high Ko values (greater than 10(8)M-1) measured, strongly suggest that "weak A" RBC determinants would process a common antigenic structure of the type: alpha-GalNAc (1 leads to 3) [alphaLFuc (1 leads to 2) beta Gal. However, the small differences of reactivity observed from one sample to an other could be related to slight variations in tridimensional configurations of oligosaccharides chains bearing the A specificity, associated with their variable antigenic content.     

Quantitative study on anomeric forms of glucose produced by alpha-glucosidases.

Anomeric forms of glucose produced from phenyl alpha-maltoside, maltose, or phenyl alpha-glucoside have been determined quantitatively by simultaneous measurements of optical rotation and reducing power, for eight kinds of glucose-producing 1,4-alpha-glucosyl hydrolases, including glucose-forming amylase from human urine, and alpha-glucosidases from pig serum, honey bee, buckwheat seed, rice seed, sugar beet seed, flint corn seed, and brewer's yeast. All the eight enzymes studied were found to produce alpha-glucose exclusively.     

北京地区中华姬鼠与大林姬鼠的数量分类研究

利用主成分分析、系统聚类分析和非参数检验,对采自北京地区的88只姬鼠标本（黑线姬鼠Apodemus agrarius除外）的10个形态分类指标进行了分析,以便确定出最具种问特异性的形态分类特征并给出定量判别标准．结果表明：除黑线姬鼠外,北京地区另有中华姬鼠（A．draco）和大林姬鼠（A．peninsulae）两种姬鼠;门齿孔后缘距上臼齿列前缘水平线的距离（x9）、上领M^1后内侧齿突向舌侧突出的程度（x1）及其与第2横嵴内侧齿突的相对大小（x2）是区分后两种姬鼠的最有效的形态分类指标;3个指标的种间界限大致为：中华姬鼠x9〈0．4mm,01≥0．2mm,x2≥0．6;大林姬鼠x9≥0．4mm,x1〈0．2mm,x2〈0．6．     

Quantitative structure-activity relationship study on some nonpeptidal cholecystokinin antagonists.

A quantitative structure-activity relationship (QSAR) analysis has been performed on a series of 1,4-benzodiazepine derivatives, which were found to act as antagonists of cholecystokinin (CCK), a gastrointestinal peptide hormone. The CCK acts with three different receptor subtypes termed as CCK-A, CCK-B, and gastrin receptor, which can be found in peripheral system, brain, and stomach, respectively. With all the three subtypes, the binding of the compounds is found to significantly depend on the lipophilicity of the compounds and their ability to form the hydrogen bonds with the receptor. However, the binding sites in CCK-A receptor seem to be slightly rigid as compared to those in CCK-B or gastrin receptor. The latter two appear to have similar binding features.     

Quantitative assessment of chromatin stability alteration in human spermatozoa induced by freezing and thawing. A flow cytometric study.

The authors examined the effect of cryopreservation on chromatin stability in human spermatozoa from 21 ejaculates. Each ejaculate was divided into four aliquots: (1) fresh aliquot, (2) frozen and thawed aliquot, (3) fresh aliquot subjected to an in vitro decondensation method, and (4) frozen and thawed aliquot subjected to the same in vitro decondensation method; all were then fixed with an ethanol fixative agent. Chromatin stainability was quantified by flow cytometric measurement of fluorochrome uptake by DNA. Study of 21 fresh aliquots showed that 37.9% of the DNA was accessible to propidium iodide. The comparative stainability between the 21 fresh and 21 frozen-thawed, undecondensed aliquots demonstrated a low but significant increase in accessibility of DNA by propidium iodide for the thawed samples: 38.7 +/- 1.7% (mean +/- SD) versus 37.9 +/- 1.3%. The biochemical action of the nuclear decondensation solution increased the accessibility of propidium iodide, but in different ways: 57.2 +/- 12.9% versus 54.7 +/- 13.7%, respectively, for fresh and frozen-thawed aliquots. Analysis of the flow cytometric histograms revealed an intermediate population of spermatozoa adjacent to the main germinal peak. This population increased significantly: 9.6 +/- 1.9% for the fresh versus 12.3 +/- 4.9% for the frozen-thawed undecondensed aliquots and 8.6 +/- 3.5% versus 12.3 +/- 4.9%, respectively, for fresh and frozen-thawed, decondensed aliquots. Because the chromatin stability of thawed spermatozoa may be a critical factor in assisted procreation, the authors discuss the effect of thermal denaturation on the nucleoprotein structures and the origin of the intermediate population of spermatozoa.     

Chronobiologic study in the domestic duck. I. Quantitative and temporal study of the action of the white light, factor releasing the gonad-stimulation

I. White light is an essential and specific external factor in the development and growth of the duck gonads. The effects of light vary according to: a. Its intensity, up to a certain maximum, beyond which the effect on the gonads becomes reduced. b. Its daily duration. c. Its duration throughout the year. Too prolonged daily exposure to light throughout the year, as in temperate climates, produces a refractory phase due to a sort of temporary fatigue of the gonad-stimulating mechanism and not to weakness or fall in the testicular reaction. d. Its distribution in time. Dividing of the exposure to light for a given time, favors growth of the testis. II. Light is not essential for testicular development in ghe duck. This development occurs in total darkness but is slower, smaller and presents fluctuations which are less marked and shorter than in natural light. When several ducks are placed in darkness in the same surroundings, the fluctuations of various individuals present certain synchronization which can only be explained by the intervention of social factors which are probably tactile. III. Submitted to constant, continuous and prolonged light for years, male ducks present, with a few differences, a behavior similar to that of subjects submitted to total darkness. Finally, light is not essential for testicular growth, but it is necessary in nature to trigger off and stimulate testicular development and ensure its annual cyclic character. Social fractors, and other external factors, also play and important role to ensure synchronization of the development of the gonads of subjects in the same group.