Purulent complications in the surgical treatment of patients with mouth cancer and their prevention]

Local purulent complications after surgical operations for mouth cancer were recorded in 49 (61.3 per cent) out of 80 cases and were mainly due to associations of 2 or more pathogens. The analysis of the factors influencing the development of the complications showed that there was no reliable increase in the number of the complications in the patients subjected at the first stage to the treatment with various antitumor agents: 17 (53.1 per cent) events in the group of the patients subjected to radiotherapy in a total focal dose of 40 Gy, 8 (72.7 per cent) events in the group of the patients subjected to radiotherapy in a dose of more than 60 Gy, 13 (59.1 per cent) events in the group of the patients treated with antitumor drugs and 8 (66.7 per cent) events in the group of the patients operated at the first stage of the treatment. The incidence of osteomyelitis was significantly higher in the group of the patients subjected to radiotherapy before the operation: 13 (30.2 per cent) events vs. 2 (5.4 per cent) in the group of the patients not subjected to radiotherapy. With increasing of the radiation dose, the incidence of osteomyelitis as well increased: 8 (25.0 per cent) osteomyelitis events in the group of the patients subjected to radiotherapy in a dose of 40 Gy and 5 (45.5 per cent) events in the group of the patients subjected to radiotherapy in a dose of more than 60 Gy. The method of osteosynthesis of the lower maxilla with titanium miniplates was also of great importance. The use of various schemes for antibiotic prophylaxis of wound infection in such patients was equally efficient.     

Effects of hormone-releasing stimuli on the area of the perivascular space in the neural lobe of the rat

Summary Neural lobes from rats subjected to neurohypophysial hormone-releasing stimuli were examined electron microscopically following fixation in 4 % tannic acid in 2.5 % glutaraldehyde. This fixation allowed the delineation of the perivascular space in the neural lobe tissue. Measurement of the area of the perivascular space showed that it was significantly increased in the rats subjected to vagal stimulation and intraarterial calcium ions compared to the control rats. The rats which had been subjected to haemorrhage as a hormonereleasing stimulus did not show any significant change in the area of the perivascular space. The significance of these findings in relation to hormone release is discussed.     

Effect of Compatible Solutes on Survival of Lactic Acid Bacteria Subjected to Drying

Four strains of lactic acid bacteria were investigated to determine if a relationship exists between accumulation of compatible solutes and the ability of cells to survive drying. Betaine was the major solute found in these lactic acid bacteria subjected to salt stress. Survival of cultures subjected to drying was considerably enhanced when this solute was accumulated by cells.     

谷氨酰胺对溃疡性结肠炎小鼠结肠损伤的影响

目的：探讨谷氨酰胺（Gln）对溃疡性结肠炎小鼠结肠黏膜损伤的影响。方法：将64只35日龄中国昆明鼠随机分为4组（n=16）：即Ⅰ组（空白对照组）、Ⅱ组（模型组）、Ⅲ组（Gln低剂量组）、Ⅳ组（Gin高剂量组）,Ⅱ、Ⅲ、Ⅳ组采用乙酸灌肠法人工复制小鼠溃疡性结肠炎模型,模型复制成功后Ⅰ、Ⅱ组均给予一定量的生理盐水灌服,Ⅲ、Ⅳ组分别灌服与生理盐水量相等的低（2mmol·kg^-1 bw）、高（4mmol·kg^-1 bw）两种浓度的Gln溶液,连续灌服7d后将小鼠处死。观察结肠病理组织学变化,检测血清内毒素含量,结肠组织的抗氧化水平、髓过氧化物酶（Ⅶ的）活性。结果：Gln减轻了由结肠炎造成的结肠黏膜的病理损伤,一定程度上缓解了结肠炎时血清内毒素急剧升高、结肠抗氧化水平降低及髓过氧化物酶活性升高等现象。结论：Gln对溃疡性结肠炎所致小鼠结肠损伤具有一定的修复作用。     

Gastrin and somatostatin in the rat antrum. The effect of removal of acid-secreting mucosa

Female rats were subjected to operations aimed at reducing the amount of oxyntic gland mucosa draining its acid secretion to the antrum. The rats were provided either with Heidenhain or Pavlov pouches reducing the oxyntic mucosa draining its secretion to the antrum by about 50% or subjected to various degrees (75, 90 and 100%) of fundectomy. Ten weeks following surgery, plasma levels of gastrin and somatostatin were assayed. At the same time, antral mucosal content of gastrin and somatostatin was determined as well as the mucosal density of these hormone-producing cells. There was a relationship between the amount of acid-secreting mucosa removed and the ensuring plasma concentration of gastrin. Thus, a stepwise increase in plasma gastrin was found with the highest levels obtained in rats subjected to 90 or 100% fundectomy. The somatostatin concentration in plasma was reduced only in rats subjected to fundectomy with the most sustained decrease in animals in which all oxyntic gland mucosa had been removed. There was also a relationship between the amount of acid-secreting mucosa removed and the gastrin content of the antral mucosa. An inverse relationship seemed to exist between antral gastrin and somatostatin concentrations. However, a significant decrease in somatostatin concentration of the antral mucosa was seen only in rats subjected to a fundectomy. The number of gastrin cells in the antral mucosa was increased in fundectomized rats only, with the largest density seen in rats deprived of all oxyntic mucosa. A corresponding decrease in the number of somatostatin cells was noticed. Our results would suggest an apparent functional relationship between antral gastrin and somatostatin cells, where the antral acid load (or pH) appears to be the major factor of physiological significance.     

采伐对红松种群结构与动态的影响

红松是我国长白山阔叶红松林的主要建群种,受森林采伐的影响,种群数量急剧下降,现已被列为国家二级保护植物。通过绘制种群静态生命表、生存函数、存活曲线和径级分布图,研究原始林,15%择伐、40%择伐和皆伐后恢复的天然次生林内,红松种群结构和动态的变化规律。结果表明:(1)采伐干扰对红松种群的波动周期影响不大,15%的择伐强度可以提高红松种群的生存期望。(2)原始林和15%择伐林内红松种群存活曲线均为DeeveyⅡ型,种群处于稳定期;40%择伐林内存活曲线介于DeeveyⅡ型和DeeveyⅢ型之间,种群由稳定期向成熟期过渡;皆伐林内存活曲线为DeeveyⅠ型,种群处在增长期。(3)原始阔叶红松林林、15%择伐林和40%择伐林内,红松种群径级结构均呈稳定的倒J型,且在幼树阶段均存在生长更新的停滞现象;与原始林相比,15%择伐林内幼树比例略有下降;40%择伐林和皆伐迹地,随采伐强度的增加,幼树比例明显增大。(4)方差分析表明,4个种群的生存过程差异较大,采伐干扰对红松种群生存过程的影响达到显著水平。     

Enzymic segregation of segmented polyurethanes containing sugar residues in the composition of the main chain

It is shown that segmented polyurethanes with D-lactose and D-maltose residues in the main polymer chain are subjected to a specific effect of enzymes: beta-galactosidase and alpha-amylase, respectively. This leads to a decrease in values of characteristic viscosity and physicomechanical indices of polyurethanes after their incubation with the mentioned enzymes. The compounds obtained are subjected to acid hydrolysis, which confirms sugar residues in the main polymer chain.     

Effect of gamma radiation on the ripening of bartlett pears

Gamma radiation at doses of 300 Krad or more inhibits the ripening of Bartlett pears (Pyrus communis L.). Immediately after irradiation there is a transitory burst of C₂H₄, which subsequently declines in fruits subjected to inhibitory doses. Ethylene production associated with ripening begins at the same time in unirradiated fruits and those subjected to noninhibitory doses, but the latter produces much more C₂H₄ at the climacteric peak. Fruits subjected to inhibitory doses produce low levels of C₂H₄ unless subjected to exogenously applied C₂H₄, whereupon they produce enough of the gas to induce ripening in unirradiated fruits.

Pears subjected to 300 and 400 Krad of gamma rays did not ripen even when held in a flowing atmosphere containing 1000 ppm of C₂H₄ for 8 days at 20°. It is concluded that the action of gamma rays on Bartlett pears involves both an inhibition of C₂H₄ production and a decreased sensitivity of the fruit to the ripening action of the gas. Ripening of Bartlett pears is inhibited by gamma radiation only when applied to preclimacteric fruit.

     

Studies on human thyroxine-binding globulin. 8. Isoelectric focusing evidence for microheterogeneity of thyroxine-binding globulin

Highly purified thyroxine-binding globulin from pooled human serum homogeneous by conventional criteria, subjected to isoelectric focusing in polyacrylamide gels in a pH gradient from 3–6, produced a pattern of at least nine stainable protein bands. All of these bands appeared to bind thyroxine. Completely desialylated thyroxine-binding globulin subjected to isoelectric focusing produced the same number and pattern of bands located at a different area in the pH gradient. Thyroxine-binding globulin purified from the serum of a single donor was subjected to isoelectric focusing. This thyroxine-binding globulin had the same pattern of protein bands with the exception that one of the major bands seen in the thyroxine-binding globulin from pooled serum was absent. Several possible explanations for these phenomena are discussed.     

Changes in structure of savanna woodlands in northern Botswana following the impacts of elephants and fire

Fluctuations in densities of woody plant species were monitored in plots within three northern Botswana woodland types subjected to elephant damage and burning. Woodlands dominated by Baikiaea plurijuga and Colophospermum mopane sustained significant changes occurring on an annual basis, whereas Acacia erioloba plots maintained a typical structure. The structure of A. erioloba woodlands appeared to be influenced by factors other than elephants and the occurrence of fire. Woodlands dominated by C. mopane plants were subjected to obtrusive elephant damage, although the densities of tall trees remained largely unchanged. The effects of fire were most prominent in B. plurijuga woodlands. Tree densities declined consistently and plants of lower height classes, such as shrubs and seedlings increased in densities in areas subjected to a high occurrence of fire.     

Use of elevated pressure to promote the difference in permeability of Adriamycin and hematoporphyrin between neoplastic and normal lung cells

The effect of increased pressure on the permeability of Adriamycin into human lung cells was studied as a function of a combination of pressure and temperature. Normal diploid lung cells as well as cells with adenocarcinoma were subjected to elevated pressures of up to 225 bars. The penetration of Adriamycin and hematoporphyrin into the cells, were assayed by use of fluorescence and absorption spectroscopy. After cells were subjected to pressure in the presence of Adriamycin, there was a greater concentration of Adriamycin in malignant cells than in normal cells. Malignant cells subjected to a pressure of 8 bars, for 210 min at 37 degrees C were found to contain twice the concentration of Adriamycin than normal cells, under the same conditions. The present results suggest that elevated pressure techniques may serve to increase the permeability of malignant cells to antineoplastic drugs.     

Morphological characteristics of an experimental dysenteric infection reproduced against a background of reduced intestinal mucosal resistance]

The authors present the results of experimental-morphological study of the intestine and other internal organs of guinea pigs subjected and not subjected to starvation infected with a dysentery culture against the background of antiepithelial serum. A marked form of the infectious process with erosive-ulcerative affection of the cecum mostly developed in 70% of the former and in 58.8% of the latter animals.     

Adenosine triphosphatase of Aspergillus nidulans: existence of isoenzymes of Ca2+-ATPase.

Ca2+-ATPase activity increased five- to six fold when the cells were subjected to growth at 37 degrees C in protein hydrolysate-supplemented media as compared to that of the cells grown in minimal media. One major isoenzyme and one minor isoenzyme were present in minimal-medium-grown cells while two major isoenzymes were present in the cells grown in protein-supplemented media. When the cells were subjected to heat stress (43 degrees C), they exhibited significantly decreased activity as compared to 37 degrees C grown cells. However, all the cultures subjected to growth at 43 degrees C showed two isoenzymes independent of growth medium.     

Supramolecular organization of regenerated silkworm silk fibers

The microstructures of N-methylmorpholine-N-oxide (NMMO) regenerated silk fibers have been characterized by atomic force microscopy from the micrometer to the nanometer scale and compared with those previously found from natural silks. Regenerated fibers show poor tensile properties and a brittle behavior, but their mechanical properties improve if subjected to post-spinning drawing. Consequently, it was hypothesized that post-spinning drawing would lead to a microstructure more similar to that of the natural material. Here we show that the microstructure of the samples not subjected to post-spinning drawing is composed of nanoglobules that differ from those found in natural silkworm silk both in size and orientation with respect to the macroscopic axis of the fiber. The microstructure of samples subjected to post-spinning drawing evolves in the sense of decreasing the size but increasing the orientation of the nanoglobules, but these effects are only observed in some regions of the fibers.     

On high-cycle fatigue of 316L stents

This paper deals with fatigue life prediction of 316L stainless steel cardiac stents. Stents are biomedical devices used to reopen narrowed vessels. Fatigue life is dominated by the cyclic loading due to the systolic and diastolic pressure and the design against premature mechanical failure is of extreme importance. Here, a life assessment approach based on the Dang Van high cycle fatigue criterion and on finite element analysis is applied to explore the fatigue reliability of 316L stents subjected to multiaxial fatigue loading. A finite element analysis of the stent vessel subjected to cyclic pressure is performed to carry out fluctuating stresses and strain at some critical elements of the stent where cracks or complete fracture may occur. The obtained results show that the loading path of the analysed stent subjected to a pulsatile load pressure is located in the safe region concerning infinite lifetime.     

Experimental investigation of some systemic effects of nitric oxide inhalation

The goal of this work was to study the influence of nitric oxide inhalation on parameters of blood proand antioxidant systems in rats under both an intact condition and experimental thermal injury. We studied 40 Wistar rats that were divided into four equal groups. The intact group was subjected to no manipulation exñept a single blood sampling, main group I was subjected to inhalation of a air mixture containing 20 ppm of nitric oxide for 10 days, the control group was subjected to thermal injury and conventional treatment, and main group II was subjected to thermal injury and daily inhalation of nitric oxide (20 ppm) for 10 days. We studied the intensity of lipid peroxidation in the blood plasma, the total antioxidant activity, the peroxide resistance of erythrocytes, the level of malondialdehyde in the blood plasma and erythrocytes, and the activity of superoxide dismutase. It was shown that daily inhalations of a mixture containing a low concentration of nitric oxide (20 ppm) modified blood oxidative metabolism in healthy and burned rats. We hypothesized that the activation of lipid peroxidation in erythrocytes accompanied by a pronounced increase in the catalytic activity of superoxide dismutase is a unified response of healthy and burned rats to exogenous nitric oxide exposure. We also observed a moderate prooxidant effect in the blood plasma of healthy animals comparable to that in the erythrocytes of these rats. In the case of thermal injury, oxidative stress tended to be corrected after the end of the course of inhalation.     

Microfingerprints of proteins through labeling acetylation of their proteolytic peptides

Microgram amounts of proteins applied to polyacrylamide gel electrophoresis were subjected to a fingerprinting procedure using a combined proteolysis-acetylation method with the aid of ¹⁴C-labeled acetic anhydride of high specific activity. After staining, gel slices were partially dried and were resoaked in a solution of a protease. After elution and acetylation, the resulting peptides were resolved in fingerprints on cellulose thin-layer chromatography plates and subjected to autoradiography with or without sensitization. Yields, completeness of fingerprinting, and possible artefacts were investigated.