Сочетание высокоуглеводной диеты и стрептозотоцина для моделирования сахарного диабета 2 типа у крыс Вистар

Relevance. To conduct a preclinical evaluation of the effectiveness of antidiabetic drugs, models simulating the pathogenesis and main manifestations of diabetes mellitus (DM) in humans are needed. The streptozotocin (STZ) model, which has received the most widespread use in the experiment, does not allow reproducing the stepwise multifactorial development of type 2 diabetes. Goal. To develop a model of type 2 diabetes using a high-carbohydrate diet in combination with a subthreshold dose of STZ in Wistar rats, characterized by hyperglycemia and insulin resistance. Methods. The animals of the control group (n = 20) received water as a drink, and the experimental group (n = 20) received a 10 % solution of fructose. After 14 days, 10 animals from each group were injected with STZ at a dose of 35 mg/kg. The blood glucose level was determined weekly. To assess insulin resistance, a oral glucose tolerance test was performed before and after the administration of STZ. Results. It was found that keeping rats on a high-carbohydrate diet for two weeks leads to a violation of glucose tolerance, which indicates insulin resistance. The introduction of STZ at a subthreshold dose of 35 mg/kg to animals on a standard diet causes an increase in the glycemic drop to 13.2 mmol/l, while the same dose of STZ against the background of a high-carbohydrate diet causes an increase in the level of hyperglycemia to 22.9 mmol/l and increases insulin resistance. Conclusion. The synergism of a high-carbohydrate diet and low doses of STZ makes it possible to obtain a model of type 2 diabetes mellitus that reproduces not only basal hyperglycemia, but also impaired glucose tolerance, which more fully corresponds to the process of developing type 2 diabetes in humans.Актуальность. Для проведения доклинической оценки эффективности антидиабетических лекарственных средств необходимы модели, имитирующие патогенез и основные проявления сахарного диабета (СД) у человека. Стрептозотоциновая (СТЗ) модель, получившая наиболее широкое распространение в эксперименте, не позволяет воспроизводить постадийное многофакторное развитие СД 2 типа. Цель. Разработать модель СД 2 типа с использованием высокоуглеводной диеты в сочетании с подпороговой дозой СТЗ у крыс Вистар, характеризующуюся гипергликемией и инсулинорезистентностью. Методы. Животные контрольные группы (n = 20) получали в качестве питья воду, а экспериментальной группы (n = 20) — 10 % раствор фруктозы. Через 14 дней по 10 животным из каждой группы вводили СТЗ в дозе 35 мг/кг. Уровень глюкозы в крови определяли еженедельно. Для оценки инсулинорезистентности до и после введения СТЗ проводили тест толерантности к глюкозной нагрузке. Результаты. Установлено, что содержание крыс на высокоуглеводной диете в течение двух недель ведёт к нарушению толерантности к глюкозной нагрузке, что свидетельствует об инсулинорезистентности. Введение СТЗ в подпороговой дозе 35 мг/кг животным, находящимся на стандартной диете, вызывает повышение уроня гликемии до 13,2 ммоль/л, в то время как эта же доза СТЗ на фоне высокоуглеводной диеты вызывает повышение уровня гипергликемии до 22,9 ммоль/л и усиливает инсулинорезистентность. Заключение. Синергизм высокоугледодной диеты и низких доз СТЗ позволяет получить модель сахарного диабета 2 типа, воспроизводящую не только базальную гипергликемию, но и нарушение толерантности к глюкозе, что в более полной мере соответствует процессу развития СД 2 типа у человека

Доклинические исследования нейротоксических свойств новых лекарственных препаратов in vivo

Neurotoxic effects are one of the common reasons for discontinuation of preclinical and/or clinical studies. Preclinical evaluation of neurotoxic effects is complicated due to a wide range of manifestations and degrees of severity. Current experimental approaches to neurotoxicity assessment are cumbersome, laborious and not adapted enough for preclinical studies in the early stages of drug development. The aim of the study was to review existing approaches to experimental assessment of neurotoxic potential of new drugs and to discuss the need for and feasibility of developing and using integrated rapid neurotoxicity tests for early assessment of a pharmacological project’s potential. The authors reviewed scientific literature and guidance documents and analysed current approaches to chemical compound neurotoxicity assessment in laboratory animals. The paper analyses the main issues of neurotoxicity assessment for new drugs and compares Irwin tests with the functional observation battery. It analyses issues related to assessment of drugs’ effects on the development and maturation of central nervous system functions at pre- and postnatal stages. It was determined that the current practice is not sufficient for assessment of potential adverse effects on cognitive functions. The authors assessed factors affecting cognitive functions of rodents during studies. The “Acute suppression of the exploratory and orientation response” and “Extrapolation escape task” tests were proposed for validation as potential rapid tests for detection of an array of organic and functional neurotoxic disorders at early stages of preclinical studies.Нейротоксические эффекты являются одной из частых причин прекращения доклинических и/или клинических исследований лекарственных препаратов. Их доклиническая оценка сложна в связи с широким спектром проявлений и степеней выраженности эффектов. Существующие экспериментальные подходы к оценке нейротоксичности громоздки, трудоемки и недостаточно адаптированы к доклиническим исследованиям лекарственных средств на ранних этапах разработок. Цель работы — анализ существующих подходов к экспериментальной оценке нейротоксического потенциала новых лекарственных препаратов с обсуждением необходимости и возможности создания и применения интегративных экспресс-тестов на нейротоксичность для ранней оценки перспективности фармакологических разработок. На основании обзора данных литературы и методических документов проведен сравнительный анализ современных подходов к оценке нейротоксичности химических соединений на лабораторных животных. Рассмотрены основные проблемы оценки нейротоксичности применительно к новым лекарственным препаратам, сопоставлены батарея тестов Ирвина и набор функциональных тестов. Проанализированы вопросы исследования влияния лекарственных препаратов на развитие и становление функций центральной нервной системы в периоды внутриутробного и постнатального развития. Констатировано, что существующая практика недостаточна в отношении оценки возможных негативных влияний на когнитивные функции. Сделана оценка факторов, влияющих на когнитивные функции грызунов в ходе исследований. Тесты «Острое угашение исследовательско-ориентировочной реакции» и «Экстраполяционное избавление» предложены к валидации в качестве возможных экспресс-тестов для выявления совокупности органических и функциональный нейротоксических нарушений на ранних этапах доклинических исследований лекарственных препаратов

Macroscopic superposition states of ultracold bosons in a double-well potential

We present a thorough description of the physical regimes for ultracold bosons in double wells, with special attention paid to macroscopic superpositions (MSs). We use a generalization of the Lipkin-Meshkov-Glick Hamiltonian of up to eight single particle modes to study these MSs, solving the Hamiltonian with a combination of numerical exact diagonalization and high-order perturbation theory. The MS is between left and right potential wells; the extreme case with all atoms simultaneously located in both wells and in only two modes is the famous NOON state, but our approach encompasses much more general MSs. Use of more single particle modes brings dimensionality into the problem, allows us to set hard limits on the use of the original two-mode LMG model commonly treated in the literature, and also introduces a new mixed Josephson-Fock regime. Higher modes introduce angular degrees of freedom and MS states with different angular properties.Comment: 15 pages, 8 figures, 1 table. Mini-review prepared for the special issue of Frontiers of Physics "Recent Progresses on Quantum Dynamics of Ultracold Atoms and Future Quantum Technologies", edited by Profs. Lee, Ueda, and Drummon

Nonlinear Coherent Modes of Trapped Bose-Einstein Condensates

Nonlinear coherent modes are the collective states of trapped Bose atoms, corresponding to different energy levels. These modes can be created starting from the ground state condensate that can be excited by means of a resonant alternating field. A thorough theory for the resonant excitation of the coherent modes is presented. The necessary and sufficient conditions for the feasibility of this process are found. Temporal behaviour of fractional populations and of relative phases exhibits dynamic critical phenomena on a critical line of the parametric manifold. The origin of these critical phenomena is elucidated by analyzing the structure of the phase space. An atomic cloud, containing the coherent modes, possesses several interesting features, such as interference patterns, interference current, spin squeezing, and massive entanglement. The developed theory suggests a generalization of resonant effects in optics to nonlinear systems of Bose-condensed atoms.Comment: 26 pages, Revtex, no figure

A synthesis of past, current and future research for protection and management of papyrus (Cyperus papyrus L.) wetlands in Africa

Papyrus wetlands (dominated by the giant sedge Cyperus papyrus L.) occur throughout eastern, central and southern Africa and are important for biodiversity, for water quality and quantity regulation and for the livelihoods of millions of people. To draw attention to the importance of papyrus wetlands, a special session entitled ‘‘The ecology of livelihoods in papyrus wetlands’’ was organized at the 9th INTECOL Wetlands Conference in Orlando, Florida in June 2012. Papers from the session, combined with additional contributions, were collected in a special issue of Wetlands Ecology and Management. The current paper reviews ecological and hydrological characteristics of papyrus wetlands, summarizes their ecosystem services and sustainable use, provides an overview of papyrus research to date, and looks at policy development for papyrus wetlands. Based on this review, the paper provides a synthesis of research and policy priorities for papyrus wetlands and introduces the contributions in the special issue. Main conclusions are that (1) there is a need for better estimates of the area covered by papyrus wetlands. Limited evidence suggests that the loss of papyrus wetlands is rapid in some areas; (2) there is a need for a better understanding and modelling of the regulating services of papyrus wetlands to support trade-off analysis and improve economic valuation; (3) research on papyrus wetlands should include assessment of all ecosystem services (provisioning, regulating, habitat, cultural) so that trade-offs can be determined as the basis for sustainable management strategies (‘wise use’); (4) more research on the governance, institutional and socio-economic aspects of papyrus wetlands is needed to assist African governments in dealing with the challenges of conserving wetlands in the face of growing food security needs and climate change. The papers in the special issue address a number of these issues

Preclinical in vivo Neurotoxicity Studies of Drug Candidates

Neurotoxic effects are one of the common reasons for discontinuation of preclinical and/or clinical studies. Preclinical evaluation of neurotoxic effects is complicated due to a wide range of manifestations and degrees of severity. Current experimental approaches to neurotoxicity assessment are cumbersome, laborious and not adapted enough for preclinical studies in the early stages of drug development. The aim of the study was to review existing approaches to experimental assessment of neurotoxic potential of new drugs and to discuss the need for and feasibility of developing and using integrated rapid neurotoxicity tests for early assessment of a pharmacological project’s potential. The authors reviewed scientific literature and guidance documents and analysed current approaches to chemical compound neurotoxicity assessment in laboratory animals. The paper analyses the main issues of neurotoxicity assessment for new drugs and compares Irwin tests with the functional observation battery. It analyses issues related to assessment of drugs’ effects on the development and maturation of central nervous system functions at pre- and postnatal stages. It was determined that the current practice is not sufficient for assessment of potential adverse effects on cognitive functions. The authors assessed factors affecting cognitive functions of rodents during studies. The “Acute suppression of the exploratory and orientation response” and “Extrapolation escape task” tests were proposed for validation as potential rapid tests for detection of an array of organic and functional neurotoxic disorders at early stages of preclinical studies