The relationship of decreased serum thyrotropin and increased colonic temperature in rats exposed to microwaves

Although decreased serum thyrotropin (TSH) concentration has been found to be part of the endocrine response pattern in rats exposed to microwaves and other stimuli, the response of individual endocrine organs was not activated simultaneously by a given irradiance. Therefore, analytical evaluation of the function of endocrine organs individually as well as collectively is required to characterize the extent of biological involvement in microwave exposure. We have studied the changes in TSH concentration in unanesthetized rats exposed to 2.45 GHz amplitude modulated (120 Hz) microwaves in the far field for 2 and 4 h, between 0 and 55 mW/cm2, and from 1 to 10 times to demonstrate any possible cumulation, acclimation, or sensitization process. Ether inhalation was administered to test the responsiveness of TSH in groups of rats that failed to respond to microwave exposure by lowering TSH concentration. In addition, groups of rats were sampled 24 h after microwave exposure to test the persistency of the microwave effect on serum TSH concentration. Results showed that TSH concentration decreased in rats after microwave exposure. Influence of microwave exposure on serum TSH concentration was independent of the number of exposures indicating absence of cumulation, acclimation, or sensitization. The microwave effect on serum TSH could be dependent on duration of exposure. Decreased TSH concentration was usually accompanied by increased colonic temperature. For 4-h exposure, the lowest irradiance was 20 mW/cm2 or a 0.3 degree C increase in colonic temperature independent of the number of exposures. For 2-h exposure, the lowest irradiance was 30 mW/cm2 or a 1.1 degree C increase in colonic temperature regardless of the number of exposures. All the rats exposed at 10 mW/cm2 for 2 h had a lower TSH concentration than those of sham-exposed rats. Occasionally, significant reduction in TSH concentration could not be found in rats exposed to 20 or 25 mW/cm2 for 2 h. None of the rats exposed at an irradiance lower than 10 mW/cm2 had any change in TSH concentration. Failure of change in TSH concentration in response to microwave exposure was not a reflection of a deficiency since these rats responded to ether inhalation by lowering their TSH concentration. The effect of microwave exposure on TSH concentration was not persistent after exposure. The relation between TSH concentration and colonic temperature was curvilinear (exponential). From these results, two mechanisms and their implications for man were discussed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of proteinase K on the energy transfer between phycobiliproteins in phycobilisomes

Spectral changes in fluorescence of phycobilisomes (PBS) of A. variabilis treated with proteinase K were studied at room and liquid nitrogen temperature. In control PBS, the relative yield of 77 K fluorescence of F686 was very high, and those of F655 and F666 were low. In PBS treated with proteinase K for less than 1 h, F686 decreased, and F655 and F666 increased. In PBS treated with proteinase K for 2 h, F655 was the main peak of fluorescence emission, F686 was the second peak, the fluorescence emission peak of F666 disappeared. In PBS treated with proteinase K for more than 8 h, F655 showed only one fluorescence emission peak.We suggested that phycobiliporteins in the PBS of A. variabilis constitute an energy transfer chain, shown as follows:{fx91-1}The linkages between APC and APC-B, C-PC and APC, and C-PC and APC-B had different sensitivity towards proteinase K.     

Dynorphin-A-(1–13) antagonizes morphine analgesia in the brain and potentiates morphine analgesia in the spinal cord

Intrathecal injection of subanalgesic doses of morphine (7.5 nmol) and dynorphin-A-(1–13) (1.25 nmol) in combination resulted in a marked analgesic effect as assessed by tail flick latency in the rat. The analgesic effect of the composite dynorphin/morphine was dose-dependent in serial dilutions so that a composition of 1/8 of the analgesic dose of dynorphin and 1/3 that of morphine produced an analgesic effect equipotent to full dose of either drug applied separately. The analgesic effect induced by dynorphin/morphine mixture was not accompanied by motor dysfunction and was easily reversed by a small dose (0.5 mg/kg) of naloxone. Contrary to the augmentatory effect of dynorphin on morphine analgesia in the spinal cord, intracerevroventricular (ICV) injection of 20 nmol of dynorphin-A-(1–13) exhibited a marked antagonistic effect on the analgesia produced by morphine (120 nmol, ICV). The theoretical considerations and practical implications of the differential interactions between dynorphin-A-(1–13) and morphine in the brain versus spinal cord are discussed.     

蝮蛇毒抗凝血活酶组份及几种蛇毒粗毒对人红细胞和血小板的作用

蝮蛇毒抗凝血活酶组分及蝗蛇毒、圆斑蝰蛇毒和眼镜蛇毒粗毒,不仅能够水解血浆中的磷脂,而且还能水解完整人红细胞膜和完整人血小板膜上的磷脂。但是五步蛇毒和金环蛇毒粗毒却不能水解完整人血小板膜上的磷脂。 扫描电镜观察表明,由于抗凝血活酶组份和几种蛇毒粗毒的作用,人红细胞和人血小板的形态发生了巨大的变化;人红细胞由正常的双圆盘形变成带刺的小球,人血小板的外形变成蜂窝状。     

Regeneration of the arterial wall in microporous,compliant, biodegradable vascular grafts after implantation into the rat abdominal aorta

Summary The ultrastructure of a new type of vascular graft, prepared from a mixture of polyurethane (95 weight %) and poly-L-lactic acid (5 weight %), was examined six weeks after implantation into the abdominal aorta of rats. These microporous, compliant, biodegradable, vascular grafts function as temporary scaffolds for the regeneration of the arterial wall.Smooth muscle cells, covering the grafts, regenerated a neo-media underneath an almost completely regenerated endothelial layer (neo-intima). These smooth muscle cells varied in morphology from normal smooth muscle cells to myofibroblasts. They were surrounded by elastic laminae and collagen fibers.Macrophages, epithelioid cells, multinucleated giant cells, fibroblasts and capillaries were present in the disintegrating graft lattices. The epithelioid cells and multinucleated giant cells engulfed polymer particles of the disintegrating grafts.The regeneration of the endothelial and smooth muscle cells is similar to the natural response of arterial tissue upon injury. The presence of macrophages, epithelioid cells, multinucleated giant cells, fibroblasts and capillaries in the graft lattices resembles the natural response of tissue against foreign body implants. Both of these responses result in the formation of a neo-artery that possesses sufficient strength, compliance and thromboresistance to function as a small caliber arterial substitute.Supported by Grant nr. 82.042 from the Dutch Heart Foundation     

Subcellular localization and glycoprotein nature of the invertase from the fission yeast Schizosaccharomyces pombe

The subcellular localization of the enzyme invertase in Schizosaccharomyces pombe cells, both repressed and derepressed for synthesis of the enzyme, was studied. Most of the invertase was found to be located outside the plasma membrane and only a small percentage was found to be associated to membranes. A substantial portion of the external enzyme remained firmly bound to cell-wall material.All of the invertase recovered in soluble form from cellular extracts reacted with concanavalin A and with the lectin from Bandeiraea simplicifolia seeds, indicating the presence in the enzyme of a carbohydrate moiety which probably contains terminal mannosyl (or structurally related) and galactosyl residues.The possibility of the presence of two different forms of invertase in S. pombe was considered. An intracellular, soluble form of invertase, devoid of carbohydrate, similar to the small invertase of the budding yeast Saccharomyces cerevisiae, was not found in S. pombe. However, the Michaelis constant for sucrose of the enzyme present in repressed cells was smaller than that of the invertase synthesized under derepressing conditions, although this difference could also be the result of a different pattern of glycosylation of the invertase synthesized under different growth conditions.     

Cloning of the pectate lyase genes from Erwinia carotovora and their expression in Escherichia coli

A hybrid cosmid coding for pectate lyase (PL) activity was identified from an Erwinia carotovora genomic library by an immunological screening method. A 7-kb DNA fragment was identified which codes for three proteins identical in size to proteins with PL activity purified from E. carotovora culture supernatants. The three proteins had apparent Mrs of 41, 44 and 44 X 10(3) as estimated by SDS-PAGE. None of the PLs were exported from Escherichia coli strain HB101 but all were found in the periplasmic space. Plant tissue was macerated by the PLs made in E. coli.     

The araBAD operon of Salmonella typhimurium LT2. I. Nucleotide sequence of araB and primary structure of its product, ribulokinase

Hybrid plasmids containing the araBAD operon of Salmonella typhimurium LT2 were characterized by Southern blot and genetic analyses. The nucleotide sequence of araB was determined. The araB gene product, ribulokinase (EC 2.7.1.16), was purified and the results of amino acid composition analysis and partial amino acid sequence are in agreement with predictions from the DNA sequence. Ribulokinase is 569 amino acid residues long and has a calculated Mr of 61 793. Ribulokinase shares significant homology with xylulose kinase from Escherichia coli. Codon usage in the araB gene does not favor those codons which have intermediate codon-anticodon binding energy.     

小柴胡黄酮的分离及结构鉴定

本文对贵州产小柴胡(B.tenue Buch.-Ham.ex D.Don)黄酮成分进行了研究。从其乙醇浸膏的水溶性物质中分离出四种黄酮醇类成分。根据光谱分析、衍生物制备、酸水解及理化常数测定,分别鉴定为芸香甙(槲皮素-3-芸香糖甙)、水仙甙(异鼠李素-3-芸香糖甙)、山萘酚和槲皮素。此类成分在该种植物中首次分离得到。     

从广州市散发性脑炎病人血清中查出雪鞋野兔病毒抗体升高

近几年来夏季,在我国南方一些省市发现一些散发性病毒性脑炎病例,主要是儿童。他们的流行性乙型脑炎抗体阴性。病因不明。 为了研究本病的病因,于1983年4月至10月,我们在广州市儿童医院收集了34例散发性脑炎病人的双份血清,15例其它病种(如百日咳、心肌炎、钩端螺旋体脑炎、多发性神经根