Phospholipid composition of blood lipids in breast and uterine cancer

A comparative analysis of quantitative changes in phospholipids, as well as peroxidation of undiluted blood lipids, plasma and blood cells in healthy women, those suffering from breast and uterus cancer, and from nonmalignant tumours (breast fibroadenoma and uterus fibroma) does not show any specific regularity typical of only malignant neoplasma and not typical of nonmalignant ones. Disturbances in the balance of negative charge phospholipids are supposed to change the electrostatic interaction in the lipid-protein complexes of supramolecular structures during the malignant growth.     

Histogenesis of endocardial tumors in rats

10 endocardial tumours (two tumours induced by N-nitrosoethylurea and eight spontaneous) of BD VI rats were examined for protein S-100 using specific antiserum in an immunoperoxidase reaction. The presence of protein S-100 in tumour cells is demonstrated in all cases and is considered as a proof of Schwann cell origin of these tumours.     

Lack of effects on heart rate and blood pressure inketamine-anesthetized rats briefly exposed to ultra-widebandelectromagnetic pulses

Fourteen Sprague-Dawley rats were exposed to pulses produced by a Bournlea ultra-wideband (UWB) pulse generator (rise time, 318-337 ps; maximum E field, 19-21 kV/m). Exposures at a repetition frequency of 1 kHz for 0.5 s or to repetitive pulse trains (2-s exposure periods alternating with 2 s of no exposure, for a total of 2 min) resulted in no significant changes in heart rate or mean arterial blood pressure. These results suggest that acute whole-body exposure to UWB pulses does not have a detrimental effect on the cardiovascular system     

Brain tumour development in rats exposed to electromagnetic fields used in wireless cellular communication

It has been suggested that electromagnetic fields (EMF) act as promoters late in the carcinogenesis process. To date, however, there is no convincing laboratory evidence that EMFs cause tumour promotion at nonthermal exposure levels. Therefore the effects of exposure to electromagnetic fields were investigated in a rat brain glioma model. Some of the exposures correspond to electromagnetic fields used in wireless communication. Microwaves at 915 MHz were used both as continuous waves (1 W), and pulsemodulated at 4, 8, 16 and 217 Hz in 0.57 ms pulses and 50 Hz in 6.67 ms pulses (2 W per pulse). Fischer 344 rats of both sexes were used in the experiments. By stereotaxic technique rat glioma cells (RG2 and N32) were injected into the head of the right caudate nucleus in 154 pairs of rats, exposed and matched controls. Starting on day 5 after inoculation, the animals were exposed for 7 hours a day, 5 days a week during 2–3 weeks. Exposed animals were kept unanaesthetized in wellventilated TEM cells producing 915 MHz continuous or modulated microwaves. Their matched controls were kept in identical TEM cells without EMF exposure. All brains were examined histopathologically and the tumour size was estimated as the volume of an ellipsoid. Our study of 154 matched pairs of rats does not show any significant difference in tumour size between animals exposed to 915 MHz, and those not exposed. Thus our results do not support that even an extensive daily exposure to EMF promotes tumour growth when given from the fifth day after the start of tumour growth in the rat brain until the sacrifice of the animal after about 16 days.     

铅暴露对发育期大鼠肾脏超微结构影响

目的:从光镜和电镜水平观察铅暴露对发育期雄性大鼠肾组织的形态学影响.方法:3周龄SD雄性大鼠,随机分为对照组和染铅组.染铅组腹腔注射0.2%乙酸铅溶液(0.2 mL/100 g体质量),隔日1次,共20次,对照组同时注射生理盐水.实验结束后,测量各组动物血铅和血中游离原卟啉,取肾组织作光镜和透射电镜观察.结果:与对照组...     

Localization of embryonic prealbumin-1 in the tissues of human malignant tumors

The distribution of human embryonic prealbumin-1 (EPA-1) has been studied in 52 different malignant tumours using indirect immunofluorescent technique and two types of antibodies to different antigenic determinants: "EPA-1" and "EPA-1S". In mesenchymal tumours (except for desmoids and chondrosarcomas) this glycoproteid was observed in the cytoplasm of tumour cells, but "EPA-1S"--in the connective-tissue fibers only. Localization of glycoproteid EPA-1 depends on the type of the used primary antibodies. EPA-1 is also observed in the connective-tissue stroma of most of epithelial tumours. A conclusion is made that transformation of EPA-1 glycoproteid synthesis from definitive to fetal form occurs in malignant tumours.     

低剂量伽玛刀照射实验性癫痫老龄大鼠海马神经元超微结构观察

目的:观察低剂量伽玛刀照射实验性老龄癫痫大鼠海马神经元超微结构的变化。方法:采用青霉素定位浸润建立老龄大鼠癫痫动物模型,将57只老龄大鼠分为对照组、癫痫组和癫痫后伽玛刀照射组。照射周边剂量12Gy,等剂量曲线为50%,0.5 h～60 d后取靶区海马制备电镜样品,透射电镜观察。结果:对照组海马神经元的超微结构正常;癫痫大鼠可见神经元细胞器明显空化,部分神经元凋亡;伽玛刀照射组早期与癫痫模型组基本一致,中期和晚期部分结构得以恢复,线粒体修复较为明显。结论:老龄癫痫大鼠经低剂量伽玛刀照射,中、晚期海马神经元的超微结构改变得以修复,可为临床治疗老龄癫痫提供形态学依据。     

Accumulation of 125J-triiodothyronine in the transplanted tumors of mice and rats

Investigations carried out in various transplantable tumours (Lewis carcinoma, carcinoma-37, melanoma B-16 in mice and sarcoma-45 in rats) did not show 125J-triiodothyronine accumulation by the tumour.     

Changes in the content and composition of gangliosides of tumors as affected by chemotherapeutic agents

The lipid-bound sialic acid (LSA) levels increased in the metastasizing Lewis lung carcinoma (3LL) and significantly decreased in blood plasma of the tumour-bearing mice after cyclophosphamide treatment correlating with the drug therapeutic effect. 5-fluorouracil that was less active in the used therapeutic doses did not cause similar changes in the LSA levels. No correlation was found between the LSA levels in adenocarcinoma 755 and the drug antitumour activity. It was observed that the content of hematoside, GM1 and GD1b sharply increases and GD3 and GD1a levels significantly decrease under the cyclophosphamide treatment of the Lewis tumour.     

Minimal paths and cuts of networks exposed to common-cause failures

A method is suggested for determining the minimal cuts and paths of a general network with common-cause failures. The minimal paths (cuts) are deduced from simple network minimal paths (cuts) obtained for the network if the common-cause failures are ignored, by appropriate manipulations with sets of path (cut) branches and sets of branches interrupted by common-cause failures. Calculation procedures are presented for an effective application of the method, to evaluate the reliability indices of the network by taking into account the statistical dependence of the failure events. Two examples are included     

Lactate and pyruvate metabolism in the tissues of rats with Walker carcinosarcoma injected with oxythiamine

The levels of L-lactate and pyruvate as well as the enzymes of their conversion (lactate dehydrogenase in direct and reverse reactions, pyruvate dehydrogenase, pyruvate kinase, alanine transaminase) have been studied simultaneously in the liver and skeletal muscle of rats bearing carcinosarcoma Walker 256, control animals and after additional oxythiamine administration. Properties of oxythiamine independent of its anticoenzymic activity manifest themselves in the body of tumour-bearing animals to a greater extent. After the antivitamin administration there occur strong inhibition of pyruvate kinase, activation of alanine transaminase, normalization of the L-lactate level in the tissues.     

The activity of nuclear endonucleases and topoisomerases in the liver of rats and in diethylnitrosamine-induced tumors

The DNA endonuclease (Aendo) and DNA topoisomerase (Atopo) activities in liver nucleus extracts of normal rats, in DENA-induced hepatomas and in liver tissues around tumours were investigated. The profile of nuclear endonucleases measured in the presence of 2 mM CaCl2 + 5 mM MgCl2, or 5 mM MnCl2, or 5 mM MgCl2, or 2 mM CaCl2 (pH 7.4), or I mM EDTA (pH 5.0) was different in normal and tumour tissues. Mn2+-dependent endonuclease was the main endonuclease in the tumour tissue, whereas Ca2+, Mg2+-dependent endonuclease was the main one in the normal liver and in the tissue around the tumour. An increase in the Mn2+-dependent endonuclease activity correlated with a decrease in the hepatoma differentiation level. Atopo of types I and II increased in the tissue around the tumour. Aendo and Atopo of cellular nuclei decreased in animals given DENA without the liver tumour.     

Downregulation of estrogen receptor alpha and beta expression in carcinogen-induced mammary gland tumors of rats

AIM AND METHODS: The recent discovery of a new isoform of estrogen receptor (ER), ER beta, has promoted the investigation of its expression on mammary gland. This study was carried out to examine the expression of ER alpha, ER beta and proliferating cell nuclear antigen (PCNA) in the carcinogen-induced mammary tumors induced by N-methyl-N-nitrosourea (MNU) or 7,12-dimethylbenz[a]anthracene (DMBA), and to compare these expression with those of age-matched normal mammary glands. RESULTS: There was significant decrease of expression of ER alpha and ER beta in the mammary gland tumors compared with age-matched normal mammary glands (p < 0.05). In mammary gland tumors, ER alpha expression was mainly located in epithelial cells, showing intranuclear staining pattern. The decrease of ER beta expression was so distant that some tumor cells did not show any expression. There was a complete loss of ER beta expression in 50% (7/14) of MNU-induced mammary gland tumors, and 68.2% (15/22) of DMBA-induced mammary gland tumors. However, there was no difference in PCNA expression between mammary gland tumors and normal mammary glands. CONCLUSION: This study represents that the decrease of expression of ER alpha and ER beta is associated with mammary carcinogenesis, and suggests that modulation of ER alpha and ER beta may be the target for the treatment of mammary gland tumors.     

Light optical and electron microscopic studies of the tumor cells in rats exposed to vinblastine against a background of increased activity of the anticoagulating system

It is shown that the damage of sarcoma 45 cells at different stages of cell life cycle occurs under the effect of vinblastine treatment against a background of higher activity of the blood anticoagulating system. A decrease in the mitotic activity, mitosis accumulation in prophase and especially in the metaphase as well as essential changes in the interphase cell ultrastructure are detected.     

Polarographic characteristics of DNA preparations isolated from the tissues of rats with Shvets' erythromyelosis

The polarographic method is used to show that the DNA preparations from the liver, spleen and tumour of leukemic rats in contrast to these preparations from the liver and spleen of the control ones possess a sharply marked electrochemical activity manifested by two peaks (peak I and peak II) in the region of the negative potential values. Peak I located in the region from--1.05 V to--1.30 V is determined by the activity of adenine and cytosine amine groups whereas peak II (from--1.45 V to--1.60 V) is caused by a protein component.     

Modeling assemblies of biological cells exposed to electric fields

Gap junctions are channels through the cell membrane that electrically connect the interiors of neighboring cells. Most cells are connected by gap junctions, and gaps play an important role in local intercellular communication by allowing for the exchange of certain substances between cells. Gap communication has been observed to change when cells are exposed to electromagnetic (EM) fields. In this work, the authors examine the behavior of cells connected by gap junctions when exposed to electric fields, in order to better understand the influence of the presence of gap junctions on cell behavior. This may provide insights into the interactions between biological cells and weak, low-frequency EM fields. Specifically, the authors model gaps in greater detail than is usually the case, and use the finite element method (FEM) to solve the resulting geometrically complex cell models. The responses of gap-connected cell configurations to both dc and time harmonic fields are investigated and compared with those of similarly shaped (equivalent) cells. To further assess the influence of the gap junctions, properties such as gap size, shape, and conductivity are varied. The authors' findings indicate that simple models, such as equivalent cells, are sufficient for describing the behavior of small gap connected cell configurations exposed to dc electric fields. With larger configurations, some adjustments to the simple models are necessary to account for the presence of the gaps. The gap junctions complicate the frequency behavior of gap-connected cell assemblies. An equivalent cell exhibits lowpass behavior. Gaps effectively add a bandstop filter in series with the low-pass behavior, thus lowering the relaxation frequency. The characteristics of this bandstop filter change with changes to gap properties. Comparison of the FEM results to those obtained with simple models indicates that more complex models are required to represent gap-connected cells     

Long-term loss stability of single-mode optical fibres exposed to hydrogen

The rate of increase in loss in single-mode optical fibres exposed to hydrogen at temperatures up to 150°C has been determined. Extrapolation down to ambient temperature of effects other than that due to interstitial hydrogen indicates that slow long-term loss increments at 1310 nm will remain less than 0.02 dB/km after 25 yr at 20°C in one atmosphere of hydrogen.     

Mechanical integrity of polysilicon films exposed to hydrofluoric acid solutions

This paper presents the results from a comparative study of Young’s modulus, residual stress, and membrane burst pressure of undoped LPCVD polysilicon films exposed to various concentrations of hydrofluoric acid (HF). Load deflection measurements on square membranes of polysilicon with residual tensile stress were used to obtain estimates of Young’s modulus, residual stress and burst pressure. The polysilicon membranes were exposed to four different solutions of the 49% by weight reagent HF including 10:1 DI water and HF, 1:1 DI water the HF, commercial 10:1 buffered oxide etchant, or pure HF (i.e. 49% by weight reagent). Two control groups were studied composed of membranes with no treatment and membranes exposed to DI water. Young’s modulus changed from an average of 190 GPa for the control groups to an average of 240 GPa for films exposed to pure HF. Residual stress values exhibited a less pronounced and opposite change, with an average of 42 MPa for the control groups and an average of 27 MPa for films exposed to pure HF. Similarly, burst pressure was seen to decrease with increasing HF concentration, ranging in value from an average of 96.5 kPa (14 psi) for the control groups to an average of 34.5 kPa (5 psi) for films exposed to pure HF. It was found that the change in the investigated mechanical properties of polysilicon was approximately equal for HF:DI solutions of HF concentration above 10%. Furthermore, for solutions of equal HF concentration, the addition of the buffering agent decreases the effect on membrane burst pressures significantly.     

Temperature dependence of reflectance and transmittance of theartery exposed to air during laser irradiation

Reflectance, transmittance, and temperature of the arterial wall exposed to air are measured during laser irradiation for different heating dynamics. Temperature dependence of the reflectance and transmittance is then deduced. The results show a competing effect between temperature and dehydration, resulting in a distinct minimum of transmittance and maximum of reflectance. As a consequence, a direct correlation of reflectance and transmittance with temperature is only possible for a specific dynamics