On the role of the pineal in thermoregulation in the pigeon

Diurnal rhythm in body temperature of pigeons subjected to different experimental conditions (pinealectomized, sham-operated, melatonin-implanted, cold-exposed) was studied under a 12 h light and 12 h dark regimen. The body temperature of pigeons during photophase was higher than that during scotophase in the normal as well as every treatment group studied. Pinealectomized pigeons showed higher body temperature in the photophase as well as scotophase, than that of the normal and sham-operated birds when examined 2 or 3 weeks following the post-surgical acclimatization to 25 or 3 degrees C. However, subcutaneous implantation of melatonin pellets into pinealectomized pigeons nullified or even reversed the hyperthermic effect of pinealectomy. Exposure of pigeons to--18 degrees C for 280 min during photophase as well as scotophase, produced a marked drop in body temperature in pinealectomized, sham-operated and normal pigeons. The pinealectomized pigeons exhibited a higher body temperature than that of the sham-operated and normal ones when exposed to--18 degrees C during the photophase, but not during the scotophase. It was concluded that while the pineal is not necessary for maintaining the daily thermal rhythm in the avian body, it has a thermoregulatory role, in that it prevents rise in body temperature in warm (25 degrees C) acclimatized and chronic cold (3 degrees C) exposed birds. In acute short-term cold (--18 degrees C) exposure however, the temperature regulatory role of the pineal was not effective during the scotophase.     

Role of the thyroid in the involution of the mesonephric Malpighian corpuscles in the chick embryo

The mesonephros of the chick embryo normally begins to regress during the second half of embryonic life. Experimental methods, such as adenohypophysis grafting, hypophysectomy or use of antithyroid drugs, which stimulate or depress the thyroid function of the embryo, modified accordingly the regressive processes occurring in the mesonephric Malpighian corpuscles, particularly at the level of the glomerular basement laminae. These results as well as the known sensitivity of the mesonephros to thyroxine and the concordance between the steps of embryonic thyroid development and the mesonephric modifications show that the thyroid normally plays a major determining role in this phenomenon.     

Manifestation of the neurotoxic effect of the organochlorine pesticide hexachlorobutadiene in the postnatal period of ontogeny in the rat

Daily peroral administration of chlororganic pesticide hexachlorobutadiene in doses 8.1 mg/kg (1/20 LD50) to pregnant rats results in certain ultrastructural changes of neurocytes and myelin fibers of the spinal cord both in the animals and their offspring (newborns and 1-2-month-old rats). By means of electron paramagnetic resonance (EPR) method, changes in intensity of the EPR-signals of free radicals in the spinal cord, ceruloplasmin of blood serum have been revealed in the experimental pregnant animals, as well as in 1-month-old rats (in the latter--in the brain, too). Gas-liquid chromatography reveals the preparation contents in the adrenals, heart, brain and spinal cord, in the uterus of the pregnant animals, as well as in corresponding organs of their offspring. Certain retardation in growth and decrease in body mass are noted in the offspring.     

Cytochemical study of the DNA and histone in the tissues of the lily anther in the course of microsporo- and gametogenesis]

The DNA and histone content in the microsporocytes, microspores, generative and vegetative cells of the pollen grain of Lilium candidum L., as well as in the anther wall tissues, was estimated by double wavelength cytophotometry. The lack of histone, as compared with DNA content, was demonstrated in the microsporocytes at the late premeiotic interphase and early meiotic prophase, as well as in the young microspores and anther wall tissues. The analysis of hydrolysis curves suggests the increase of non-condensed chromatin during endothelial cell differentiation.     

Race and ethnicity in the construction of the nation in Spain: the case of the Maragatos

Nationalism and its counterpart, modernism, are projects that involve the attempt to homogenize and incorporate the masses through the creation of a majority identity that usually leads to the classification of certain deviant groups as ‘others’. In Spain, civic and ethnic nationalisms driven by the state have historically drawn on cultural and biological notions of ethnicity and race to construct a representation of the Maragatos as ‘cursed peoples’, while at the same time homogenizing and incorporating them into the nation in practice. By tracing a genealogy of the origins and evolution of the representations of Maragato otherness created during the Enlightenment era, the Franco dictatorship and the current super-modern period, this paper argues that representations of otherness significantly influence current research agendas and understandings of identity well beyond the disappearance of the actual subjects described as others.     

The reflection of the simulated movement of a sound source in the evoked potentials of the inferior colliculus in the cat

EP series from the cat's inferior colliculus were recorded following binaural stimulation with click series imitating sound source movement due to variation of the interaural time delay (and thus evoking in man the sensation of the moving fused auditory image, FI). The "movement effect" was evaluated as the change in the EP amplitude during the series. The movement effect itself as well as its predominance under conditions of the ipsilateral FI movement as compared to those of the contralateral movement, proved to be connected with greater effectiveness of the contralateral stimulation relative the ipsilateral one.     

The role of the methylation in the detoxication of arsenate in the rabbit

The biotransformation, tissue retention, intracellular binding and biokinetics of arsenic were studied in rabbits exposed to [74As]arsenate (0.4 mg As/kg body wt., i.v.). Inhibition of the methyltransferase activity by injection of periodate-oxidized adenosine (PAD) caused a marked decrease of the formation of [74As]dimethylarsinic acid (DMA), which gave rise to 1.5-4 times increased tissue levels of 74As. This is almost the same as reported for rabbits given arsenite in combination with PAD and was due to a rapid reduction of the arsenate to arsenite which bound to the tissues. Only about 30% of the arsenate given was excreted unchanged in the urine, indicating that a large part was reduced to AsIII. Thus the methylation to DMA seems to be almost as important for the detoxication following exposure to arsenate as that following exposure to arsenite. In the rabbits with normal methylating capacity 50-70% of the produced AsIII was methylated to DMA. The liver was the only organ in which DMA was present 1 h after the administration, indicating that this is the main site of the methylation. The DMA was rapidly cleared from all tissues except the thyroid.     

Changes in the electromechanical activity in the course of tetanic contraction

The functioning of excitation-contraction coupling during tetanic contraction was investigated on frog skeletal muscle. The effect of the calcium release blocker dantrolene was tested on electrically evoked twitches and tetanic contractions. It was shown that the first: developmental stage of tetanus is inhibited by dantrolene as well as a twitch contraction, and does not influenced by calcium-free medium. This substantiates it as based on "voltage dependent Ca-release" (VDCR) mechanism of activation, when depolarization directly opens the rhyanodin receptor calcium channels. The next stage: the long lasting plateau of tetanic contraction, is directly dependent on external Ca2+ entry and also inhibited by dantrolene, and therefore may be described as "calcium-induced Ca-release" (CICR) activation mechanism. It is proposed that such change in ECC mechanism taking place during tetanic contraction, can occur also in conditions of natural muscle activity, because of its rhythmical nature.     

Understanding the parts in terms of the whole

Metabolism is usually treated as a set of chemical reactions catalysed by separate enzymes. However, various complications, such as transport of molecules across membranes, physical association of different enzymes, giving the possibility of metabolite channelling, need to be taken into account. More generally, a proper understanding of the nature of life will require metabolism to be treated as a complete system, and not just as a collection of components. Certain properties of metabolic systems, such as feedback inhibition of the first committed step of a pathway, make sense only if one takes a broader view of a pathway than is usual in textbooks, so that one can appreciate ideas such as regulation of biosynthesis according to demand. More generally still, consideration of metabolism as a whole puts the emphasis on certain systemic aspects that are crucial but which can pass unnoticed if attention is always focussed on details. For example, a living organism, unlike any machine known or conceivable at present, makes and maintains itself and all of its components. Any serious investigation of how this can be possible implies an infinite regress in which each set of enzymes needed for the metabolic activity of the organism implies the existence of another set of enzymes to maintain them, which, in turn, implies another set, and so on indefinitely. Avoiding this implication of infinite regress represents a major challenge for future investigation.     

DNA synthesis in various sections of the brain and in the liver of the rat in early postnatal ontogeny

The intensity of 3H-thymidine incorporation in DNA, as well as DNA content of the liver, brain stem, cerebellum, and neocortical tissues have been investigated in 1-32 days old rats. It was shown that the kinetics of the studied parameters is principally different in the tissues investigated.     

Participation of the globus pallidus in the organization of stereotyped behavior in the cat

Electrical stimulation of the globus pallidus of cats produces a stereotype behaviour like that following the injection of high doses of d,1-amphetamine. This drug enhances pallidal response. On the other hand, pallidal stimulation facilitates formation of amphetamine-induced stereotypy which weakens after bilateral destruction of the globus pallidus. Neuroleptic haloperidol in very low doses abolishes pallidal as well as amphetamine-induced stereotypy. As supposed pallidal stereotypy may be connected with the disturbance of nigro-strio-pallidal relations.     

The role of vitamin E in the biosynthesis of the isoprenoid region of the ubiquinone molecule in the rat liver

A decrease in the CoA and acetyl-CoA amount in the rat liver tissue by 34.8 and 29.4%, respectively, as well as inhibition of the biosynthesis rate of mevalonic acid from [I-14C] acetyl-CoA in the postmitochondrial liver fraction by 17.9% as compared to the control are found against a background of E-hypovitaminosis. The last change is not associated with the inhibition of the 3-oxy-3-methylglutaryl-CoA-reductase activity and may not be one of reasons which cause the biosynthesis disturbances in the isoprenoid part of the ubiquinone molecule in this organ. alpha-Tocopherol activates the ubiquinone biosynthesis from [2-14C] sodium acetate in the liver of rats with E-hypovitaminosis under conditions of 30 min preincubation and is not efficient when added in combination with actinomycin D. Probably, such an effect of alpha-tocopherol is realized at the level of RNA synthesis and is associated with the biosynthesis activation of short-living RNA.     

Some rules in the ordering of nucleotides in the DNA.

Natural DNA sequences contain distinct nearest neighbor patterns. Eukaryotic as well as prokaryotic sequences show a consistent hierarchy in the frequencies of appearance of most doublets.     

Variations in the arrangement of tonofilaments in the epidermis of teleost fish

Tonofilaments in epithelial cells of teleost skin can be aligned as bundles or skeins of appreciable bilk, or form a pattern of smaller bundles oriented in various directions, or there may be a condition where individual tonofilaments interlace. If sufficiently close together, interwoven tonofilaments can form a basket-like structure, a “capsule”, proximally in the cell. This arrangement, previously known in epithelial cells of Myxinoids, occurs in localised sites in various teleosts of diverse taxonomic position, for instance in clupeids and gadids. A less intimate interlacing of cortical tonofilaments can accompany a modification of the perinuclear cytoplasm previously described, by light microscopy, as “vesiculated”, as in the middle layers of the epidermis in Periophthalmus. In head epidermis of Sprattus, the outer layers of cells contain proximal capsules, but the middle layers consist of flattened cells with a restricted perinuclear cytoplasm, peripheral tonofilaments, and a second population of filaments of a larger calibre. One implication of these results is that the cytoskeleton can undergo profound modification as cells progress from the basal to the superficial layers of the epidermis.     

Recovery of intertidal mussel beds in the Waddensea: use of habitat maps in the management of the fishery

In the Waddensea, musselbed distribution and abundance has decreased. Management is aiming at increase of area of beds. Fisheries have been regulated. Mussel beds are slowly recovering, and localities where recovery occurs can be predicted reasonably well. Active restoration of beds has not been necessary, as long as newly formed beds are protected from fisheries. Potential suitable sites should be protected from bottom-disturbing activities which might influence the substrate for spatfall such as cockle beds and tube-building polycheates.     

Electrochemical immobilization of glucose oxidase in the polyacrylamide coating in the presence of glutaraldehyde

A new electrolyte composition for preparing polyacrylamide coatings with immobilized glucose oxidase that contains glutaraldehyde as a component is proposed. The polarographic behaviour of glutaraldehyde at increased ZnCl2 concentrations answers the criterion of electrochemical polymerization. Glutaraldehyde improves cross-linkage within polyacrylamide, provides an increase of the coating mass and its better quality and adherence, as well as the covalent binding of the enzyme during electrochemical immobilization.     

Examination of the roles of selenium in the Kaschin-Beck Disease

The Kaschin-Beck Disease, an endemic disease in China, occurs in low-selenium areas. Using human embryonic cartilage cell as a system, the effect of selenite and another etiological factors, such as, organic matters in water, and grain from disease regions, were studied. It was shown that Se(IV), as well as superoxide dismutase, could prevent the cells from damage by organic matters, and increase the activity of GSHpx and decrease the production of lipid peroxide. A model test of adrenalin autooxidation was carried out, and it was found that the oxy-radical can be eliminated by Se(IV). Thus, it was assumed, that selenium was a protective factor and free radical scavenger for Kaschin-Beck Disease.     

生物医药关键技术发展趋势

近年来,生物医药研究人员正在药物的设计、发现、试验、制备,以及检测技术、其他诸如纳米、信息、光学等高技术的融合应用方面致力于更新观念的研究开发,并已取得众多突破,在相关领域形成新的技术趋势。在药物设计方面,随着遗传信息方面的研究进展越来越快,核酸为靶的药物设计已成为新的热点;在疫苗方面,基因疫苗的研制已成为新方向,其技术应用趋向可调控、更安全、更高效生产等,科研人员同时还致力于解决基因疫苗的安全性;在治疗方面,抗体工程和组织工程分别成为药物治疗和组织器官再造的热点;新型药物输送技术正成为业界追逐的目标,药物传输公司正在开发多技术平台,提高药物的效能,减少不良反应和降低成本;药物安全问题已在全球范围内达成共识,美、英、日、欧盟等国均在积极开展药物安全性方面的研究,开发药物安全监测系统;疾病诊断与检测的新技术表现为更高效、准确、快速、早期的趋势,科研人员同时还致力于降低诊断检测产品的价格,以使更多人受益;IT技术、光电技术、纳米技术等新技术正被积极应用于生物医药领域,为大型制药公司和生物技术公司提供药物发现、设计、毒性研究等更新途径的新技术系统。     

Ultrastructural changes in the pinealocytes of the rat in the late period after hypophysectomy

Changes in the ultrastructure of epiphyseal pinealocytes were examined 3 weeks after hypophysectomy in infantile male rats in order to study functional relations of pineal gland with the hypothalamo-hypophyseal system. In hypophysectomized animals the functional activity of pineal secretory cells was found to decrease. Besides, the symptoms of suppression of biosynthetic processes and energy metabolism, as well as lipid infiltration and degradation of intercellular contacts, were observed.     

Biological activity in vivo of insulin analogues modified in the N-terminal region of the B-chain

[AlaB5]Insulin as well as a hybrid analogue of insulin and "insulin-like growth factor" (IGF-I), in which the N-terminal amino-acid sequence H-Phe-Val-Asn-Gln- of the B-chain has been replaced by the tripeptide H-Gly-Pro-Glu-of IGF-I, have been prepared by the partial-synthetic route. Their biological activity in vivo has been compared with that of other analogues in rabbits, mice and rats as far as data are available. These rodents respond differently, rats being less sensitive to modifications than rabbits and mice. The results explain unexpected discrepancies discussed in previous papers.