Studies on the state of phosphatidylcholine molecules before and after ultrasonic and gel-filtration treatments

Phosphatidylcholine vesicles, prepared by prolonged ultrasonic irradiation in solution at 2°C under nitrogen followed by chromatography at 4°C on a Sepharose 4B column, were analyzed by thin-layer chromatography. No detectable differences were found in the chemical state of phosphatidylcholine molecules before and after the treatment by ultrasonic irradiation and gel-filtration. Special emphasis is given to the differences between the procedures for the preparation of homogeneous phosphatidylcholine vesicles and the conventional ultrasonication method.     

Studies of the binding of ethidium bromide to cells before and after enzyme treatment

Summary Binding of ethidium bromide (EB) to cells before and after HCl, pepsin and RNase treatment was investigated by spectrophotometric and fluorimetric methods. Binding isotherms, calculated with the McGheevon Hippel equation, taking EB as a non-interacting ligand, revealed the influence of these treatments on the fluorescence characteristics of the cells which were measured by flow-through cytofluorimetry. Thus pepsin- and RNase-treated cells have a reduced intercalation capacity due to the loss of cytoplasmic RNA and RNA hydrolysis, respectively. HCl alone, or in association with pepsin, increased the equilibrium constant K considerably. Thus at low free EB concentrations the enhanced EB affinity of acid-pretreated cells generates a high fluorescence intensity, by comparison with treatments at neutral pH. This result contradicts the interpretation of high EB binding to acid pretreated cells which is commonly believed to be due to hydrolytic histone removal from potential intercalation sites.With increasing free EB concentrations the fluorescence intensities of RNase- and pepsin-treated cells culminate at the same level due to their almost identical intercalation capacities. Consequently, quantitative DNA analysis of pretreated cell suspensions with EB can only be performed if the alteration, induced by the pretreatment, has previously been studied.     

Determination of human apolipoprotein C-II by electroimmunoassay. Studies on standardization and determination before and after physical training

1. Human VLDL and HDL were fractionated by sequential ultracentrifugation until free of contaminant plasma proteins. 2. Column chromatofocusing method was used to isolate apolipoprotein C-II from apoVLDL and apo HDL. C-apoprotein peak was rechromatofocused and the second peak was the apo C-II (pI 4.7, homogeneous band on SDS slab gel). 3. New Zealand white rabbits were immunized with apo C-II. Antiserum gave a single precipitate are of identity between whole serum, apoVLDL, apoHDL and apo C-II. 4. Apo C-II concentration was measured by electroimmunoassay method. During standardization 1% Triton X-100 improved the rocket shapes and contours. Total delipidation did not affect the assay system and so the antigenic determinants of apo C-II are all available to antiserum. The lowest concentration of apo C-II possible to determine with this method was 70 ng/sample well. 5. There was no difference between the apo C-II values before (39.8 +/- 7.1 mg/l, n = 19) and after (41.6 +/- 6.4 mg/l, n = 19) moderate physical training among normolipemic subjects. 6. Specific immunoprecipitation technique was also used to determine apo C-II content in standard pool serum.     

Validity of resting energy expenditure predictive equations before and after an energy-restricted diet intervention in obese women

Background

We investigated the validity of REE predictive equations before and after 12-week energy-restricted diet intervention in Spanish obese (30 kg/m²>BMI<40 kg/m²) women.

Methods

We measured REE (indirect calorimetry), body weight, height, and fat mass (FM) and fat free mass (FFM, dual X-ray absorptiometry) in 86 obese Caucasian premenopausal women aged 36.7±7.2 y, before and after (n = 78 women) the intervention. We investigated the accuracy of ten REE predictive equations using weight, height, age, FFM and FM.

Results

At baseline, the most accurate equation was the Mifflin et al. (Am J Clin Nutr 1990; 51: 241–247) when using weight (bias:−0.2%, P = 0.982), 74% of accurate predictions. This level of accuracy was not reached after the diet intervention (24% accurate prediction). After the intervention, the lowest bias was found with the Owen et al. (Am J Clin Nutr 1986; 44: 1–19) equation when using weight (bias:−1.7%, P = 0.044), 81% accurate prediction, yet it provided 53% accurate predictions at baseline.

Conclusions

There is a wide variation in the accuracy of REE predictive equations before and after weight loss in non-morbid obese women. The results acquire especial relevance in the context of the challenging weight regain phenomenon for the overweight/obese population.     

树舌多糖结构修饰前后CD谱比较研究

树舌多糖ＣＦ２ａ经１５ｍｍｏｌ／Ｌ１０４ｈ选择氧化,继以次氯酸氧化、得修饰树舌多糖ＣＦ２ａｍ,其结构分析表明侧链氧化率为６５％,以Ｊ－５００Ｃ圆二色性仪比较测定ＣＦ２ａ,ＣＦ２ａ一刚果红复合物及ＣＦ２ａｍ在不同ｐＨＴ的ＣＤ谱,结果表明紫外区中性多糖ＣＦ２ａ缺少结构信息,而修饰后的ＣＦ２ａｍ在ｐＨ２．０时有很强的有序结构信息,ＣＦ２ａ分子整体修饰、即其与刚果红形成复合物时,除提供很强的外源Ｃｏｔｔｏｎ效应外也提供了一些有序结构信息．     

Trees before and after Darwin

Phylogenetic trees published before Darwin’s On the Origin of Species are scarce. Lamarck (1809) and Barbançois (1816; J Phys Chim Hist Nat Arts 82, 444) are the first and only trees devoted to illustrating the genealogical connections between organisms of different species and different higher taxa. In the late 18th and early 19th centuries, most of the trees depicted in papers dealing with natural history were classifications; classifications in the shape of trees, but classifications nonetheless. Those published by Bronn (1858) are a good example. After Darwin, phylogenetic trees incorporating the time dimension flourished. In the first half of the 20th century, the Modern Synthesis failed to renew and rejuvenate the intuitive construction of trees. It wasn’t until the appearance of Hennig’s phylogenetic systematics that the real nature of the connection between phylogeny and the pre‐Darwinian concept of homology was made clear.     

Studies of the binding of ethidium bromide to cells before and after enzyme treatment.

Binding of ethidium bromide (EB) to cells before and after HCl, pepsin and RNase treatment was investiaged by spectophotometric and fluorimetric methods. Binding isotherms, calculated with the McGheevon Hippel equation, taking EB as a non-interacting ligand, revealed the influcence of these treatments on the fluorescence characteristics of the cells which were measured by flow-through cytofluorimetry. Thus pepsin- and RNase-treated cells have a reduced intercalation capacity due to the loss of cytoplasmic RNA and RNA hydrolysis, respectively. HCl alone, or in association with pepsin, increased the equilibrium constant K considerably. Thus at low free EB concentrations the enchanced EB affinity of acid-pretreated cells generates a high fluorescence intensity, by comparison with treatments at neutral pH. This result contradicts the interpretation of high EB binding to acid pretreated cells which is commonly believed to be due to hydrolytic histone removal from potential intercalation sites. With increasing free EB concentrations the fluorescence intensities of RNase- and pepsin-treated cells culminate at the same level due to their amost identical intercalation capacities. Consequently, quantitative DNA analysis of pretreated cell suspensions with EB can only be performed if the alteration, induced by the pretreatment, has previously been studied.     

P300 variations in parkinsonian patients before and during dopaminergic monotherapy: a suggested dopamine component in P300

P300 was recorded, using an ‘odd ball’ paradigm, in 18 parkinsonian patients before and during dopaminergic monotherapy. The data were compared with those of a homogeneous standard group of 20 subjects.The main finding was an increase in the P300 latency of parkinsonian patients before therapy, which recovered during dopaminergic monotherapy. In 11 voluntary healthy subjects the same therapy did not produce a reduction of the P300 latency.The data are discussed in relation to a possible dopaminergic component in P300 origin.     

Atomic force microscope observation on biomembrane before and after peroxidation

Atomic force microscope (AFM) has been used to visualize the morphological change on the surface of erythrocyte membrane before and after oxidation. A smooth surface of intact erythrocyte cell was observed, while treatment by ferrous ion and ascorbate induced hemolysis of intact erythrocytes, generated many holes with average size of 146.6 +/- 33.2 nm in diameter (n=28) on membrane surface as seen by AFM. Ghost membrane and its inside-out vesicles were also used for the experiment. Skeleton structure and protein vesicles could be observed on the surface of an intact erythrocyte membrane before oxidation. Sendai virus induced fusion of inside-out vesicles seemed suppress peroxidation, while no such effect was observed in ghost membrane and erythrocyte systems.     

Effects of difenin on experimental parkinsonian syndrome

The aim of this study was to investigate the effect of difenin on parkinsonian syndrome and the generator of pathologically enhanced excitation (GPEE) in the caudata nuclei (CN). Repeated i. p. administration of MPTP in 12 month rats induced oligokinesis and rigidity followed by the high amplitude slow and rapid waves in the CN and in sensorimotor cortex (SC). The changes of the electrical activity in the CN were more prominent then in SC. I.p. injection of difenin (20 mg/kg) resulted in an increase of motor activity and decrease of rigidity in rats. The reduction of extrapyramidal symptoms were correlated with at the inhibition of GPEE in the CN. These data suggest that difenin can be a part of the complex pathogenetic therapy of parkinsonian syndrome.     

Studies on thymocyte subpopulations in guinea pigs. X. Rosette-forming ability of thymocyte subpopulations before and after incubation in vitro

Thymocytes spontaneously proliferating in vitro were labelled with 3H-thymidine, and the distribution of label among rosette-forming cells (RFC+) and nonrosetting cells (RFC-), as well as in populations differing in buoyant density, was measured by liquid scintillation counting and autoradiography before and after incubation for 24 h. Initially most labelled cells (88%) belonged to the low-density (1a) subpopulation, the majority being RFC+. After incubation for 24 h, low-density nonrosetting thymocytes (1a, RFC-) contained the highest amount of label. A decreased rosette formation occurred not only in labelled cells but also in the population as a whole, and in separately incubated high-density cells. The decreased rosette formation was mainly caused by a change in rosette-forming ability of viable high-density cells, however in part also by decreased viability. A shift from low to high density occurred among labelled cells during incubation and was shown to occur in both RFC+ and RFC-. The decreased rosette formation of labelled cells during in vitro culture contrasts with the increase earlier observed in vivo and may therefore represent affinity alterations or a down-regulation of the rosette receptor in vitro. We conclude that the observed changes in density, but not in rosette-forming ability, may reflect normal differentiation.     

Mammographic measurements before and after augmentation mammaplasty

Thirty-five augmented women underwent mammography using both the standard implant-compression technique and, when possible, the implant-displacement technique; all had preaugmentation film-screen mammography available for evaluation. The area of mammographically visualized breast tissue before and after augmentation mammaplasty was measured using a transparent grid. Patients with subglandular implants had a mean decrease of 49 percent of measurable tissue area with compression mammography and a 39 percent decrease with displacement mammography. Patients with submuscular implants had a 28 percent decrease in measurable tissue area with compression mammography and a 9 percent decrease with displacement mammography. Anterior breast tissue was seen better with displacement mammography; posterior breast tissue, with compression mammography. Most patients had some degree of parenchymal scarring and lower image quality after augmentation. State-of-the-art mammography was not possible in most patients augmented with silicone-gel-filled implants.