Practical aspects of therapy for glutaric aciduria type 1

Treatment of many of the diseases in the panel of expanded newborn screening includes dietary therapy. Glutaric aciduria type 1 (GA1) is a hereditary disorder caused by mutations in the gene GCDH, encoding glutaryl‑CoA dehydrogenase, an enzyme in the amino acid metabolic pathways. The decreased activity of the enzyme leads to accumulation of neuro‑ toxic metabolites. The recommended treatment approaches for GA1 are the prescription of specialized nutrition products, levocarnitine, and symptomatic management. In 2021, clinical guidelines for the treatment of this rear disease were published in Russian Federation. To provide for the timely treatment, it is essential for a practitioner involved in the care patients with such a rare disorder as GA1 to have the knowledge of the principles of management, as well as practical algorithms for diet calculation.The article gives a detailed case‑based description of management during metabolic decompensation and the choice of dietary therapy for GA1 patients of different age groups

Coupling of kinesin ATP turnover to translocation and microtubule regulation: one engine, many machines

The cycle of ATP turnover is integral to the action of motor proteins. Here we discuss how variation in this cycle leads to variation of function observed amongst members of the kinesin superfamily of microtubule associated motor proteins. Variation in the ATP turnover cycle among superfamily members can tune the characteristic kinesin motor to one of the range of microtubule-based functions performed by kinesins. The speed at which ATP is hydrolysed affects the speed of translocation. The ratio of rate constants of ATP turnover in relation to association and dissociation from the microtubule influence the processivity of translocation. Variation in the rate-limiting step of the cycle can reverse the way in which the motor domain interacts with the microtubule producing non-motile kinesins. Because the ATP turnover cycle is not fully understood for the majority of kinesins, much work remains to show how the kinesin engine functions in such a wide variety of molecular machines

Практические аспекты терапии при глутаровой ацидурии типа 1

Treatment of many of the diseases in the panel of expanded newborn screening includes dietary therapy. Glutaric aciduria type 1 (GA1) is a hereditary disorder caused by mutations in the gene GCDH, encoding glutaryl‑CoA dehydrogenase, an enzyme in the amino acid metabolic pathways. The decreased activity of the enzyme leads to accumulation of neuro‑ toxic metabolites. The recommended treatment approaches for GA1 are the prescription of specialized nutrition products, levocarnitine, and symptomatic management. In 2021, clinical guidelines for the treatment of this rear disease were published in Russian Federation. To provide for the timely treatment, it is essential for a practitioner involved in the care patients with such a rare disorder as GA1 to have the knowledge of the principles of management, as well as practical algorithms for diet calculation.The article gives a detailed case‑based description of management during metabolic decompensation and the choice of dietary therapy for GA1 patients of different age groups.Лечение многих болезней, входящих в программы расширенного неонатального скрининга, включает в себя диетотерапию. Глутаровая ацидурия 1‑го типа (ГА1) – наследственное заболевание, обусловленное мутациями в гене GCDH, кодирующем глутарил‑КоА‑дегидрогеназу, фермент, задействованный в метаболизме аминокислот. Снижение активности данного фермента приводит к накоплению в организме нейротоксичных метаболитов. При ГА1 рекомендовано назначение специализированных продуктов лечебного питания, левокарнитина и применение симптоматической терапии. В 2021 г. были опубликованы российские клинические рекомендации по лечению этого редкого заболевания. Врачу, который в своей практике сталкивается с таким редким заболеванием как ГА1, необходимо знать принципы лечения и практические алгоритмы расчета при назначении диетотерапии.В данной статье подробно на клинических примерах рассмотрены вопросы, касающиеся ведения в период метаболической декомпенсации и правильного подбора диетотерапии у пациентов разного возраста, страдающих ГА1

Основополагающее значение понятий «амбулаторность» и «неамбулаторность» в комплексной оценке состояния пациентов с мышечной дистрофией Дюшенна

Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease due to a mutation in the gene encoding dystrophin synthesis. In patients, muscle damage and atrophy progresses, the ability to move independently decreases as well as respiratory and cardiac functions. At various stages of the disease, different methods of care and treatment of patients with DMD are used. The clinical effect of new methods of DMD target therapy may depend on the stage of development of the disease (ambulatory or non‑ambulatory). To date, there are no unified criteria for assessing the status of a patient in terms ambulatory. In clinical trials and real clinical practice, different approaches are used to assess the patient’s status. However, the conclusion about the functional capabilities is critical for patients with DMD as approaches in management of patients in ambulatory and non‑ambulatory stages differ significantly. This necessitates expert consensus to achieve consistency and avoid any of discrepancies on that issue.The paper reviews the available published data on the concepts of “ambulatory” and “non‑ambulatory” used in clinical trials, real clinical practice, international standards and recommendations. As a conclusion of this analysis, it is proposed in real clinical practice to interpret “ambulation” in DMD patients as ability to walk without the use of assistive devices and without specifying the distance and time, and “non‑ambulation” as condition in which the patient is forced to constantly use a wheelchair both indoors and outdoors.Мышечная дистрофия Дюшенна (МДД) – фатальное нервно‑мышечное заболевание, обусловленное мутацией гена, кодирующего белок дистрофин. В результате развивающегося и прогрессирующего повреждения и атрофии мышц пациенты теряют способность к самостоятельному передвижению, у них развиваются респираторные и кардиологические нарушения. На разных стадиях МДД используются разные методы ведения. Клинический эффект новых методов таргетной терапии МДД может зависеть от стадии болезни на момент назначения лечения: амбулаторной, когда пациент ходит самостоятельно, или неамбулаторной, когда способность к самостоятельной ходьбе утрачена. Сегодня нет единых критериев статуса пациента с точки зрения амбулаторности, а в клинических исследованиях и реальной практике используются разные подходы к ее оценке. Тем не менее определение понятий «амбулаторность» и «неамбулаторность» критично для пациентов с МДД, так как подходы к ведению пациентов в амбулаторной и неамбулаторной стадии болезни различны. В статье представлены обзор, сравнение и анализ определений «амбулаторность» и «неамбулаторность», использованных в клинических исследованиях, реальной медицинской практике, международных стандартах и рекомендациях.По итогам анализа предлагается в реальной клинической практике трактовать амбулаторность больных МДД как способность ходить без использования вспомогательных средств и без указания дистанции и времени, а потерей амбулаторности считать состояние, при котором пациент вынужден постоянно использовать инвалидное кресло для передвижения как вне дома, так и в домашних условиях

Глутаровая ацидурия типа 1 у детей. Клиническое представление 46 случаев, диагностированных в России

Background. Glutaric aciduria type 1 is an autosomal recessive disease caused by mutations in the GCDH gene, which encodes the enzyme glutaryl‑CoA dehydrogenase. Metabolic crisis in type 1 glutaric aciduria is an acute life‑threatening condition that requires careful diagnosis with a number of other conditions and the immediate initiation of pathogenetic therapy.Materials and methods. Clinical manifestations, neuroimaging characteristics of the disease were studied in 46 patients with diagnosed glutaric aciduria type 1 confirmed by biochemical and molecular genetic methods. Methods: gas chromatography with mass spectrometry, tandem mass spectrometry, Sanger sequencing, chromosomal microarray analysis of the exon level.Results and discussion. A retrospective analysis of anamnestic and clinical data was carried out, and the nature and age of disease manifestation, provoking factors, a spectrum of clinical manifestations and neuroimaging data were assessed.Conclusion. How initiated treatment prevents progression of neurological symptom relief and patient adaptation. With the help of the goal, it is necessary to inform pediatricians, neurologists and neuroradiologists about this feature of the course of glutaric aciduria type 1 in order to increase the clinical alertness of this disease.Введение. Глутаровая ацидурия типа 1 – аутосомно‑рецессивное заболевание, обусловленное мутациями в гене GCDH, кодирующем фермент глутарил‑КоА дегидрогеназу. Метаболический криз при глутаровой ацидурии типа 1 – это острое жизнеугрожающее состояние, требующее тщательной дифференциальной диагностики с рядом других состояний и незамедлительного начала патогенетической терапии.Материалы и методы. Клинические проявления, нейровизуализационные характеристики болезни изучены у 46 пациентов с подтвержденным биохимическими и молекулярно‑генетическими методами диагнозом глутаровой ацидурии типа 1. Методы: газовая хроматография с масс‑спектрометрией, тандемная масс‑спектрометрия, секвенирование по Сэнгеру, хромосомный микроматричный анализ экзонного уровня.Результаты и обсуждение. Проведен ретроспективный анализ анамнестических данных, клинических, а также оценены характер и возраст манифестации болезни, провоцирующие факторы, спектр клинических проявлений и нейровизуализационные данные.Заключение. При отсутствии массового неонатального скрининга крайне важное значение имеет ранняя диагностика болезни, так как своевременно начатое лечение поможет предотвратить прогрессирование неврологической симптоматики и способствовать адаптации пациентов. С этой целью необходимо информировать врачей‑педиатров, неврологов и нейрорадиологов об особенностях протекания глутаровой ацидурии типа 1 для повышения клинической настороженности в отношении данного заболевания

Kinetics processivity and the direction of motion of Ncd.

The kinetic mechanism of the nonclaret disjunctional protein (Ncd) motor was investigated using the dimer termed MC1 (residues 209-700), which has been shown to exhibit negative-end directed motility (Chandra et al., 1993). The kinetic properties are similar to those of the monomeric Ncd motor domain (Pechatnikova and Taylor, 1997). The maximum steady-state ATPase activity of 1.5 s(-1) is half as large as for the monomeric motor. Dissociation constants in the presence of nucleotides showed the same trend but with approximately a two-fold decrease in the values: K(d) values are 1.0 microM for ADP-AlF(4), 1.1 microM for ATPgammaS, 1.5 microM for ATP, 3 microM for ADP, and 10 microM for ADP-vanadate (in 25 mM NaCl, 22 degrees C). The apparent second-order rate constants for the binding of ATP and ADP to the microtubule-motor complex (MtMC1) are 2 microM(-1) s(-1). Based on measurements at high microtubule concentrations the kinetic steps were fitted to the scheme,[see text] where N refers to one head of the dimer and T, D, and P stand for ATP, ADP, and inorganic phosphate. k(1) and k(-4) are the first-order rate constants of the transition induced by the binding of mant ATP and mant ADP respectively. ADP release is the main rate-limiting step in the MtMC1 mechanism. The binding of the MC1-mant ADP complex to microtubules released less than half of the mant ADP (alternating site reactivity). The second mant ADP is only released by the binding of nucleotides that dissociate the MtMC1 complex (ATP and ADP but not AMPPNP). The apparent rate constant for dissociation of the second mant ADP is four times smaller than the first and much smaller than the rate of dissociation of MtMC1 by ATP or ADP. These results are explained by a model in which MC1.ADP is first dissociated from the microtubule by ATP, followed by rebinding to the microtubule by the ADP-containing head. Ncd may follow a different reaction pathway than does kinesin, but the differences in rate constants do not explain the opposite direction of motion. The kinetic evidence and the high ratio of motile velocity to ATPase support a nonprocessive, low duty cycle mechanism for the Ncd motor

DYSTONIA IN CHILDREN (A LECTURE)

Distonia is a movement disorder associated with imbalance of excitatory neurotransmitters, and it is characterized by continuous or episodic muscle contraction that forms repetitive stereotyped movements and/or postures. Dystonic hyperkinesia of younger children can be included into the structure of many syndromes that have different etiological factors, prognosis, and treatment. Different clinical variant of dystonia are represented: idiopathic benign dystonia with the onset in the first year of life; dystonia against the background of residual damage to the nervous system; hereditary idiopathic and symptomatic dystonia with various syndromes and metabolic diseases; similar conditions. Diagnostics of dystonia of children requires application of a wide range of examinations, including neuroimaging, continuous video electroencephalographic monitoring, genetic research. Differential diagnosis of dystonia of children is performed regarding various paroxysmal states of childhood of the epileptic and non-epileptic nature