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.     

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.     

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.     

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.     

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.     

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.     

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.     

畜禽微生物耐药组研究进展

目前,绝大部分抗生素用于给人类提供肉奶蛋等食品的畜禽,由此产生的抗生素耐药性对全球公众健康造成了巨大威胁。为了降低畜禽生产环节抗生素耐药性向人类的传播,首先需要明确畜禽消化道或产品微生物携带哪些耐药基因。耐药组指的是某个环境微生物群落全部耐药基因的总和,近年来对于畜禽生产过程中耐药组分析成为研究热点之一。本文综述了基于测序技术研究畜禽(猪、鸡、反刍动物)消化道以及乳中微生物耐药组组成及其影响因素的最新进展,并提出了未来研究方向,包括耐药组研究方法的标准化、基于宏转录组的耐药组基因表达研究,以及可移动遗传元件所携带的耐药基因等,旨在为调控畜禽养殖过程中耐药基因提供思路。     

Study of the presence of the spores of Clostridium botulinum in honey in Brazil

The isolation of Clostridium botulinum from honey samples is described. Botulism is characterized as an intoxication provoked by ingestion of contaminated foods with this toxin. Infant botulism happens by the ingestion of spores of C. botulinum together with food that in special conditions of the intestinal tract, such as those present in babies of less than 1 year old, will allow the germination and colonization of the intestine with production and absorption of botulinic toxin. The samples were subjected to dilution and to a thermal shock and cultivated in modified CMM (Difco). Cultures were subjected to Gram smears and toxicity tests in mice. The toxic cultures were purified in RFCA (Oxoid) plates and incubated in anaerobic jars. Positive samples were typed using the mouse assay neutralization test. From the 85 honey samples analyzed, six were positive for C. botulinum (7.06%), and identified as producers of type A, B, and D toxins.     

Changes in the ratio of quantum-vesicular parameters in the presence of disrupted synaptic transmitter secretion in the neuromuscular junctions of mammals

To test the vesicular hypothesis of quantum release, some parameters of synaptic vesicles (SV) and miniature end plate potentials (MEPPs) were compared in phrenic neuromuscular junctions of rats poisoned with tetanus toxin (TT). The poisoning with TT that suppresses the transmitter release led to marked changes in the distribution of MEPPs amplitudes and SV diameters as compared to normal, namely to the transformation of unimodal histograms for both parameters to polymodal ones. The transformation was accompanied by a significant increase in variation coefficients of both distributions, thus indicating the disturbances of vesicle-quantum formation. The total number of SV in the poisoned terminal increased by 59% which might reflect both the lifetime situation characteristic for normal and/or real accumulation of the transmitter quanta as a result of the TT-hampered exocytosis through the presynaptic membrane, since during the reactivating action of ouabain, the transmitter release level from the poisoned terminal exceeded that for normal to about the same measure. The results obtained may be regarded as providing evidence in favour of the vesicular hypothesis.     

Cost-effectiveness of the modifications in the quality assurance system in radiotherapy in the example of in-vivo dosimetry

PurposeTo present the methodology for the evaluation of cost-effectiveness of the quality assurance protocol modifications associated with increasing demands on accuracy and reliability in radiotherapy and to present results on cost-effectiveness of in-vivo dosimetry as the chosen example of a technical procedure.Material and methodsIn-vivo dosimetry was used as an example of a quality assurance procedure, whose modifications have an impact on several procedures in the QA system and thus on the cost of radiotherapy. An analysis of 6864 patients, treated between 2001 and 2005 for tumours in the head and neck, breast, pelvis, or lung, was performed. The quality of radiotherapy was expressed as the accuracy of dose delivery and the cost was estimated from labour, equipment and materials.ResultsModifications implemented in the quality assurance protocol have gradually improved the quality of irradiation. Mean deviations between measured and calculated doses, recorded for several groups of treatment sites, were reduced from ?1.5% to 0.5%, 3.4% to 1.4%, 3.9% to 0.1% and ?2.1% to 1.8% for head and neck, breast, pelvis and lung respectively. The standard deviations of the measured values decreased also consistently. Total monthly cost in radiotherapy (related to in-vivo dosimetry) increased from € 4376 to € 10,696 while the unitary cost of radiotherapy procedures remained at the same level. The predominant cost component of in-vivo dosimetry was labour, limited at first to physics staff and later extended to quality assurance personnel and technicians.ConclusionThe application of the presented methodology revealed cost-effectiveness relationships in tested technical procedures.     

The participation of oxygen in the process of the interphase death of T-lymphocytes following irradiation in vivo

The ability of lymphocytes to inhibit proliferation of non-syngeneic stem cells decreases differently after exposure in vivo and in vitro. The causes of the observed differences and the mechanism of radiation impairment of this function under different irradiation conditions have been investigated. Cells exposed in vivo die in the interphase irreversibly. The newly formed lymphocytes start the repair process as late as one month after irradiation. The injury to in vivo exposed cells is severer due to the presence of oxygen in tissues. A definite time interval is needed for the damaging effect of oxygen radicals to be implemented: the effect is maximum as early as 4 h following irradiation. With in vivo exposure under hypoxic conditions the functional activity of lymphocytes is the same as that of lymphocytes irradiated in vitro with the same dose. In vitro irradiation of lymphocytes at a high oxygen content causes a decrease in the functional activity of cells.     

Realization of antimalarial measures in the period of eradication of the consequences of a flood in the Stavropol Territory in 2002

As the result of the high flood, an increase in the area of anopheligenic water reservoirs occurred on the inundated territories, which created favorable conditions for the proliferation of Anopheles mosquitoes, the vectors of malarial plasmodia, thus creating the threat of the formation of the local sources of malaria in case of its penetration from other regions unfavorable with respect to this disease. In the affected towns and regions hydrotechnical measures aimed at decreasing the surface of anopheligenic water reservoirs, as well as measures aimed at the decrease in the number of the larval and imaginal stages in the development of mosquitoes, were taken, which made it possible to prevent the probable epidemiological aggravations in malaria.     

Phenomenon of apoptosis in the survival of enterobacteria in the parasite-host system

Data on the apoptosis phenomenon with enterobacteria used as a model are presented. One of the mechanisms regulating the vital activity of eukaryotic cells is, together with cell proliferation and differentiation, the phenomenon known as "apoptosis". This physiological process of the eukaryotic cells death is used by many parasites in parasite--host relationships in different epitopes. The system known to trigger programmed cell death, is the surface receptor Fas, the receptor of tumor necrosis factor (TNF alpha) activated by the corresponding FasL ligand and TNF alpha, which further triggers the cascade mechanisms of the execution program. In various representatives of enterobateria different proteins serve as Fas ligand, viz. protein IpaB in Shigella flexneri, SipB activating converting enzyme IL-1 beta, identical to capsase-1, in Salmonella spp., YopP in Yersinia spp. Still the mechanism triggering apoptosis in Yersinia spp. has some original features. In Escherichia coli alpha-hemolysin is the factor triggering the suicidal program, the triggering mechanism being mediated by an increase in intracellular calcium ions.     

Ethanol in the stems of trees

Acetaldehyde and ethanol are usually thought to be produced in plant tissues as a mechanism to tolerate hypoxic conditions. We have found acetaldehyde and ethanol to be common in the vascular cambium and in the transpiration stream of trees. In nonflooded trees, acetaldehyde and ethanol concentrations averaged 130 and 40 μ M in the cambium and 130 and 50 μ M in the xylem sap, respectively. Ethanol concentrations in the transpiration stream and the cambium increased to as much as 5 m M upon flooding. Ethanol concentrations in the vascular cambium of Populus deltoides could not be eliminated by placing logs from nonflooded trees in a pure oxygen environment for as long as 96 h, but increased by almost 3 orders of magnitude when logs were exposed to low external partial pressures of O₂. These results suggest that the vascular cambium was not hypoxic, despite the presence of acetaldehyde, ethanol and the enzymes for their synthesis.     

Age-related changes in the content of fibrous proteins in the rat tissues.

An attempt was made to establish a relationship between the content of elastin and collagen in the rat tissues during the process of aging. The content of collagen fractions and elastin in the rat liver, lung and skin, as well as the elastolytic activity of blood serum were determined. It was found that the concentration of elastin as well as the elastolytic activity of blood serum are increasing during the maturation of rats and the total collagen content is increasing too. After the animals reached the age from twelve to twenty four months--above mentioned values began to decrease. It is concluded that the changes in the content of the two fibrous proteins of the connective tissue depend on age.     

Perturbations in the carbon budget of the tropics

The carbon budget of the tropics has been perturbed as a result of human influences. Here, we attempt to construct a ‘bottom‐up’ analysis of the biological components of the budget as they are affected by human activities. There are major uncertainties in the extent and carbon content of different vegetation types, the rates of land‐use change and forest degradation, but recent developments in satellite remote sensing have gone far towards reducing these uncertainties. Stocks of carbon as biomass in tropical forests and woodlands add up to 271 ± 16 Pg with an even greater quantity of carbon as soil organic matter. Carbon loss from deforestation, degradation, harvesting and peat fires is estimated as 2.01 ± 1.1 Pg annum^?1; while carbon gain from forest and woodland growth is 1.85 ± 0.09 Pg annum^?1. We conclude that tropical lands are on average a small carbon source to the atmosphere, a result that is consistent with the ‘top‐down’ result from measurements in the atmosphere. If they were to be conserved, they would be a substantial carbon sink. Release of carbon as carbon dioxide from fossil fuel burning in the tropics is 0.74 Pg annum^?1 or 0.57 MgC person^?1 annum^?1, much lower than the corresponding figures from developed regions of the world.     

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.     

Delimitation of the maritime boundary in the gulf of Maine area

The compulsory dispute settlement regime included in the 1982 Law of the Sea Convention is recognized as one of the most comprehensive in a modern international convention. Yet, in the recent application of this regime, the question has arisen as to whether the procedural prerequisites associated with the LOS Convention's compulsory dispute settlement mechanism are so arduous as to avoid binding and compulsory jurisdiction in most instances. This article addresses that question by examining, in particular, the reasoning of the Southern Bluefin Tuna arbitration tribunal, which found Article 281 of Section 1 of the LOS Convention to bar jurisdiction to the compulsory dispute settlement mechanism prescribed by the Convention, and offers suggestions as to how states might distinguish or overcome the barriers imposed by the Southern Bluefin Tuna tribunal in future cases.