Integrated top-down and bottom-up proteomics mass spectrometry for the characterization of endogenous ribosomal protein heterogeneity / 药物分析学报

Ribosomes are abundant,large RNA-protein complexes that are the sites of all protein synthesis in cells.Defects in ribosomal proteins(RPs),including proteoforms arising from genetic variations,alternative splicing of RNA transcripts,post-translational modifications and alterations of protein expression level,have been linked to a diverse range of diseases,including cancer and aging.Comprehensive character-ization of ribosomal proteoforms is challenging but important for the discovery of potential disease biomarkers or protein targets.In the present work,using E.coli 70S RPs as an example,we first developed a top-down proteomics approach on a Waters Synapt G2 Si mass spectrometry(MS)system,and then applied it to the HeLa 80S ribosome.The results were complemented by a bottom-up approach.In total,50 out of 55 RPs were identified using the top-down approach.Among these,more than 30 RPs were found to have their N-terminal methionine removed.Additional modifications such as methylation,acetylation,and hydroxylation were also observed,and the modification sites were identified by bottom-up MS.In a HeLa 80S ribosomal sample,we identified 98 ribosomal proteoforms,among which multiple truncated 80S ribosomal proteoforms were observed,the type of information which is often overlooked by bottom-up experiments.Although their relevance to diseases is not yet known,the integration of top-down and bottom-up proteomics approaches paves the way for the discovery of proteoform-specific disease biomarkers or targets.

Determination uncertainty of aluminum residues in human albumin using top-down evaluation / 中国输血杂志

【Objective】 To evaluate the determination uncertainty of aluminum residues in human albumin by inductively coupled plasma mass spectrometry (ICP-MS). 【Methods】 The aluminum residues in human albumin was determined by ICP-MS, and the top-down method was applied to assess the reasons of uncertainty and calculate the uncertainty. 【Results】 The relative standard uncertainty of the aluminum content in human albumin at the three quality control levels was 0.54 ng/mL, 1.68 ng/mL and 4.54 ng/mL, respectively, which met the requirements of the guidelines for bioanalytical methods in the Chinese Pharmacopoeia(2020). 【Conclusion】 The top-down method is simple and quick to assess the uncertainty of aluminum residues in human albumin, and is suitable for the uncertainty assessment of analytical methods in biological laboratories.

Characteristics of visual conduction under Top-down perceptual processing / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To study the visual efficiency and characteristics of Top-down perceptual pathway in children.<p>METHODS: Totally 26 children volunteers in the outpatient department from January to June 2020 were selected. We adopted the photos of children's self-face as the Top-down perceptive fixation point pictures. The N75 time, P100 peak time, P100 amplitude and P100 repolarization time were recorded by graphic visual evoked potential(PVEP)examination.<p>RESULTS: Different visual perception pathway had no significant effect on the latency of N75, while different spatial frequencies have a significant effect on the N75 time. The latency of N75 was prolonged under high frequency spatial stimulation. The interaction between visual perceptual processing path and spatial frequency has a significant effect on the peak time of P100.Under Top-down condition, the peak time of P100 was significantly shortened under high-frequency spatial stimulus. Different visual perception paths and spatial frequencies had significant effects on P100 amplitude, and Top-down perceptual processing and spatial frequencies had significant effects on the time of P100 wave repolarization, while the interaction between processing paths and spatial frequencies had no significant effects.<p>CONCLUSION:Under Top-down visual perceptual, the visual conduction velocity and visual condition efficiency are improved in children's visual process.

Functional discovery and production technology for natural bioactive peptides / 生物工程学报

Bioactive peptides play important roles in promoting human health, such as lowering blood pressure, blood sugar and blood lipid, anti-obesity, and anti-cancer. Thus, exploring functional bioactive peptides and developing efficient production technologies are of crucial importance. Herein, we review the development of function discovery and production technology for natural bioactive peptides. Presently, the top-down and bottom-up approaches are mainly used for the function discovery and production of natural active peptides. The top-down approach includes the direct extraction and identification for functional discovery, and the direct extraction, enzymatic hydrolysis and microbial fermentation for production. The bottom-up approach includes the polypeptide modification and database mining for functional discovery, and the chemical synthesis, enzyme synthesis, recombinant expression and cell-free synthesis for production. The top-down approach is usually associated with complicated process, lower efficiency, higher cost, harder quality control, and uncertain functionality, while the bottom-up approach is more suitable for the development of peptide drugs but difficult to be used for functional foods. With the technology development of sequencing and mass spectrometry, it is easier to obtain the proteomic information of various organisms at the molecular level. Based on the proteomic information, the top-down and bottom-up approaches can be combined to overcome the disadvantages of using these two approaches alone, thus providing a new strategy for the rapid development and production of natural active peptides.

RELATIONSHIP BETWEEN ISOKINETIC LEG STRENGTH AND KNEE FRONTAL PLANE PROJECTION ANGLE DURING SINGLE LEG SQUAT AMONG MALE JUNIOR ATHLETES

@#Background: Those with increased dynamic knee valgus are vulnerable to increased risk of non-contact knee injuries. However, studies on the top down kinetic chain of lower limb mechanics during dynamic motions such as single leg squat (SLS) among trained males were scarce. Objective: The objective of the study was to evaluate the relationship between isokinetic hip and knee strength and frontal plane projection angle (FPPA) of the knee joint during SLS. Methods: Thirty-two male junior athletes (twelve cyclists, ten runners and ten squash players) were screened for excessive dynamic knee valgus (DKV) prior to participation. Only those within the normal value of DKV were included. Their hip and knee isokinetic strength in sagittal plane were evaluated at 60º/s of angular velocity for both legs using dynamometer. Two dimensional knee FPPA was evaluated during SLS at 60º of knee flexion. Pearson correlation was evaluated between knee FPPA during SLS and isokinetic leg strength. Results: Correlations between knee FPPA and hip and knee isokinetic strength were not statistically significant except between knee flexion peak torque/body weight (r = -0.35, p = 0.05) and hamstring to quadriceps ratio (r = -0.39, p = 0.03) of non-dominant leg. Conclusions:Isokinetic hip and knee strength and knee FPPA during SLS was correlated only for non-dominant leg during SLS among male junior athletes. DKV during SLS may be reduced through strengthening the muscles around hip and knee joints.

Implant treatment on anterior cross-bite of a patient who had orthognathic surgery 20 years ago / 대한치과보철학회지

Orthognathic surgery of skeletal Class III malocclusion improves oral function and facial appearance. The greater amount of skeletal discrepancy, the greater amount of teeth movement required for decompensation, and this often causes pathological changes in periodontal tissue especially in lower anterior dentition. We made a Top-Down treatment plan with personalized analysis using Face Hunter, Plane System and ARCUS Digma II, in order to resolve severe mobility and cross-bite of lower anterior teeth for 49-year-old female patient who had undergone orthognathic surgery 20 years ago due to skeletal Class III malocclusion and mandibular prognathism. Lower anterior teeth were extracted and alveoloplasty was done. After healing of the wound, immediate loading was conducted immediately after implant placement. Final restorations were fabricated Zirconia using CAD/CAM, and inserted intraorally screw-retained type. During 6-month follow-up, no abnormal episodes of restorations were observed, and obtained satisfactorily both of functional and esthetic outcomes.

Top-down vs. Bottom-up: alterações no processamento de informações durante a indução de fadiga mental / Top-down vs. bottom-up: alterations in information processing during mental fatigue induction

A Fadiga Mental (FM) ocorre durante ou após um período prolongado de demanda cognitiva repetitiva somado a recompensas insatisfatórias. Este estudo pretende investigar alterações no processamento de informações top-down e bottom-up nocontrole inibitório durante a indução de FM através do protocolo de tarefa cognitiva por tempo prolongado. Participaram do experimento 19 sujeitos (9 homens) com idades entre 18 e 24 anos (M=21,21 DP=1,77), submetidos ao paradigma Go/NoGo contendo cinco blocos de 250 tentativas com intervalos de 30 segundos entre blocos, totalizando 50 minutos de atividade. A ANOVA para medidas repetidas sugere efeito significativo do tempo de realização da tarefa no aumento no tempo de reação do processamento top-down, F4,15 = 3,66, p<0,05, no número de erros por omissão, F4,15 = 4,75, p<0,05, e uma redução no tempo de resposta do processamento bottom-up, F4,15 = 5,39, p<0,05. Estes achados sugerem que a realização de uma tarefa cognitiva durante um período prolongado provoca prejuízo significativo no desempenho cognitivo, com ênfase no processamento de informações top-down, não impedindo a realização de um comportamento, mas prejudicando sua qualidade de execução.

Mental Fatigue (FM) occurs during or after a prolonged period of repetitivecognitive demand coupled with unsatisfactory rewards. This study intends toinvestigate changes in the processing of top-down and bottom-up information oninhibitory control during FM induction through the cognitive task protocol for aprolonged time. A total of 19 subjects (9 males) aged 18 to 24 years (M = 21.21 SD= 1.77) were submitted to the Go / NoGo paradigm containing five blocks of 250trials with 30-second intervals between blocks, totalizing 50 minutes of activity.The ANOVA for repeated measures suggests a significant effect of the time ofaccomplishment of the task in the increase in the time of reaction of the top-downprocessing, F4,15 = 3.66, p <0.05, in the number of errors by default, F4,15 = 4.75, p<0.05, and a reduction in response time of bottom-up processing, F4.15 = 5.39, p<0.05. These findings suggest that performing a cognitive task over a prolongedperiod causes significant impairment in cognitive performance, with an emphasison top-down information processing, not hindering the performance of a behaviorbut impairing its quality of execution.

The effects of endogenous and exogenus orienting of attention on source memory / Efectos de la orientación de la atención endógena y exógena en la memoria de contexto

Abstract The aim of this study was to determine the effects of endogenous and exogenous orienting of attention on episodic memory. Thirty healthy participants performed a cueing attention paradigm during encoding, in which images of common objects were presented either to the left or to the right of the center of the screen. Before the presentation of each image, three types of symbolic cues were displayed to indicate the location in which the stimuli would appear: valid cues to elicit endogenous orientation, invalid cues to prompt exogenous orientation and neutral or uncued trials. The participants' task was to discriminate whether the images were symmetrical or not while fixating on the center of the screen to assure the manifestation of only covert attention mechanisms. Covert attention refers to the ability to orient attention by means of central control mechanisms alone, without head and eye movements. Trials with eye movements were excluded after inspection of eye-tracker recordings that were conducted throughout the task. During retrieval, participants conducted a source memory task in which they indicated the location where the images were presented during encoding. Memory for spatial context was superior during endogenous orientation than during exogenous orientation, whereas exogenous orientation was associated with a greater number of missed responses compared to the neutral trials. The formation of episodic memory representations with contextual details benefits from endogenous attention.

Resumen El objetivo del estudio fue determinar los efectos de la orientación de la atención endógena y exógena en la memoria episódica. Treinta participantes sanos realizaron el paradigma de atención con claves durante la codificación, en el que se presentaron imágenes a la izquierda o derecha del centro de la pantalla. Antes de cada imagen se proyectaron tres tipos de claves que indicaban el lugar en el que se presentaría la imagen: claves válidas (orientación endógena), claves inválidas (orientación exógena) y claves neutras. Los participantes tenían que discriminar si las imágenes eran simétricas o no mientras fijaban su mirada al centro de la pantalla para asegurar solo la manifestación de mecanismos de atención encubierta. La atención encubierta se refiere a la habilidad para orientar la atención sólo por medio de mecanismos de control central sin movimientos de los ojos o la cabeza. Los ensayos con movimientos oculares fueron excluidos después de inspeccionar los registros de movimientos oculares. En la recuperación, los participantes realizaron una tarea de memoria de contexto en la que indicaron la posición en la que se había presentado cada imagen durante la codificación. La recuperación del contexto espacial fue superior en los ensayos de orientación endógena que en los ensayos de orientación exógena. La formación de representaciones de la memoria episódica con detalles contextuales se beneficia de los mecanismos de atención endógena.

Neural Signature for Auditory Hallucinations in Schizophrenia: A High-Resolution Positron Emission Tomography Study with Fludeoxyglucose (¹⁸F)

OBJECTIVE: Auditory hallucinations (AHs) are a core symptom of schizophrenia. We investigated the neural signature of AHs by comparing hallucinating patients with schizophrenia with non-hallucinating patients with schizophrenia. METHODS: We recruited hallucinating patients with schizophrenia meeting the criteria for persistent, prominent, and predominant AHs (n=10) and non-hallucinating patients with schizophrenia (n=12). Various clinical assessments were performed incluing Psychotic Symptom Rating Scale for Auditory Hallucinations. Using fludeoxyglucose (¹⁸F) positron emission tomography, regional differences in neural activity between the groups were analyzed. RESULTS: The regions of interest analysis showed significantly lower standardized uptake value ratio (SUVR) in the superior, middle, and inferior frontal gyri, and higher SUVR in the putamen in patients with AHs versus patients without AHs. These findings were confirmed in the voxel-wise analysis. CONCLUSION: Our findings indicate that hypoactivity in the frontal and cingulate gyri, coupled with hyperactivity in the temporal gyrus and putamen, may contribute to the pathophysiology of AHs.

Early Biologic Treatment in Pediatric Crohn's Disease: Catching the Therapeutic Window of Opportunity in Early Disease by Treat-to-Target / 대한소아소화기영양학회지

The emergence of mucosal healing as a treatment goal that could modify the natural course of Crohn's disease and the accumulating evidence showing that biologics are most effective in achieving mucosal healing, along with the success of early treatment regimens for rheumatoid arthritis, have led to the identification of early Crohn's disease and development of the concept of catching the therapeutic window during the early disease course. Thus, an increasing number of pediatric gastroenterologists are adopting an early biologic treatment strategy with or without an immunomodulator. Although early biologic treatment is effective, cost and overtreatment are issues that limit its early use. Currently, there are insufficient data on who will benefit most from early biologics, as well as on who will not need early or even any biologics. For now, top-down biologics should be considered for patients with currently known high-risk factors of poor outcomes. For other patients, close, objective monitoring and accelerating the step-up process by means of a treat-to-target approach seems the best way to catch the therapeutic window in early pediatric Crohn's disease. The individual benefits of immunomodulator addition during early biologic treatment should be weighed against its risks and decision on early combination treatment should be made after comprehensive discussion with each patient and guardian.

Review and prospect on preparation technology of drug nanocrystals in the past thirty years / 药学学报

Nanocrystals is a hot topic of poorly soluble drug delivery system under development. Nanocrystals is different from the nanoparticles for drug unloading in polymer materials, and nanocrystals is different from solid dispersion system, in which the drug maintains crystals state. Nanocrystals has a simple preparation process, represents an effective technology in the improvement of solubility and bioavailability of poorly soluble drugs, and has a very promising industrialization application and development potential. In this paper, we retrospect the development history of drug nanocrystals technology, review development of the preparation methods of nanocrystals, and analyze the existing problems to provide a reference to the development of drug nanocrystals preparation.

Protein-species quantitative venomics: looking through a crystal ball

In this paper we discuss recent significant developments in the field of venom research, specifically the emergence of top-down proteomic applications that allow achieving compositional resolution at the level of the protein species present in the venom, and the absolute quantification of the venom proteins (the term "protein species" is used here to refer to all the different molecular forms in which a protein can be found. Please consult the special issue of Jornal of Proteomics "Towards deciphering proteomes via the proteoform, protein speciation, moonlighting and protein code concepts" published in 2016, vol. 134, pages 1-202). Challenges remain to be solved in order to achieve a compact and automated platform with which to routinely carry out comprehensive quantitative analysis of all toxins present in a venom. This short essay reflects the authors' view of the immediate future in this direction for the proteomic analysis of venoms, particularly of snakes.(AU)

It is time for top-down venomics

The protein composition of animal venoms is usually determined by peptide-centric proteomics approaches (bottom-up proteomics). However, this technique cannot, in most cases, distinguish among toxin proteoforms, herein called toxiforms, because of the protein inference problem. Top-down proteomics (TDP) analyzes intact proteins without digestion and provides high quality data to identify and characterize toxiforms. Denaturing top-down proteomics is the most disseminated subarea of TDP, which performs qualitative and quantitative analyzes of proteoforms up to ~30 kDa in high-throughput and automated fashion. On the other hand, native top-down proteomics provides access to information on large proteins (> 50 kDA) and protein interactions preserving non-covalent bonds and physiological complex stoichiometry. The use of native and denaturing top-down venomics introduced novel and useful techniques to toxinology, allowing an unprecedented characterization of venom proteins and protein complexes at the toxiform level. The collected data contribute to a deep understanding of venom natural history, open new possibilities to study the toxin evolution, and help in the development of better biotherapeutics.(AU)

Protein-species quantitative venomics: looking through a crystal ball

Abstract In this paper we discuss recent significant developments in the field of venom research, specifically the emergence of top-down proteomic applications that allow achieving compositional resolution at the level of the protein species present in the venom, and the absolute quantification of the venom proteins (the term protein species is used here to refer to all the different molecular forms in which a protein can be found. Please consult the special issue of Jornal of Proteomics Towards deciphering proteomes via the proteoform, protein speciation, moonlighting and protein code concepts published in 2016, vol. 134, pages 1-202). Challenges remain to be solved in order to achieve a compact and automated platform with which to routinely carry out comprehensive quantitative analysis of all toxins present in a venom. This short essay reflects the authors view of the immediate future in this direction for the proteomic analysis of venoms, particularly of snakes.

It is time for top-down venomics

Abstract The protein composition of animal venoms is usually determined by peptide-centric proteomics approaches (bottom-up proteomics). However, this technique cannot, in most cases, distinguish among toxin proteoforms, herein called toxiforms, because of the protein inference problem. Top-down proteomics (TDP) analyzes intact proteins without digestion and provides high quality data to identify and characterize toxiforms. Denaturing top-down proteomics is the most disseminated subarea of TDP, which performs qualitative and quantitative analyzes of proteoforms up to ~30 kDa in high-throughput and automated fashion. On the other hand, native top-down proteomics provides access to information on large proteins (> 50 kDA) and protein interactions preserving non-covalent bonds and physiological complex stoichiometry. The use of native and denaturing top-down venomics introduced novel and useful techniques to toxinology, allowing an unprecedented characterization of venom proteins and protein complexes at the toxiform level. The collected data contribute to a deep understanding of venom natural history, open new possibilities to study the toxin evolution, and help in the development of better biotherapeutics.

Producing Collagen Nano-fibril Arrays by the Molecular Broom Mechanism of Atomic Force Microscopic Tip / 分析化学

By takung advantage of atomuc force mucroscopes'( AFM) capabuluty of manupulatung and processung materuals on the mucroscale, we duscovered and unvestugated a top-down preparatuon method of buologucal macromolecular nano-fubrul arrays. 50μg/mL solutuon of rat taul type I collagen monomers was used to coat the muca surface to form a proteun membrane. In the AFM Contact Mode, the AFM tup then manupulated the membrane wuth appropruate force between 100 nN and 1 mN, thus producung patterned collagen nano-fubrul arrays wuth specufuc oruentatuons. The nano-fubruls are averagely 2-5 nm un heught and 150-350 nm un wudth. Based on the relatuonshup between the structure of such nano-fubrul arrays and the AFM scannung patterns, we unvestugated and duscussed the formatuon of the proteun fubrul arrays, and verufued the molecular broom mechanusm of the AFM tup. Thus preparatuon method could potentually provude an effucuent technuque to manufacture cell culture vessels, produce buologucal probes wuth hugh specufucutues, and synthesuze novel mucro/nano materuals as well.

Top-down Design of Health and Family Planning Informatization / 医学信息学杂志

〔Abstract〕 In order to advance the comprehensive and balanced development of health and family planning informatization in Beijing on the whole, according to the theoretical method of top -level design and in combination with actual situations of health and family plan-ning informatization in Beijing , the paper studies practices on top -level design from the aspect of technical routes and organization and implementation, and elaborates achievements of top -level design.

Measurement uncertainty evaluation of 23 clinical biochemical items by top-down method / 医疗卫生装备

To evaluate the measurement uncertainty of 23 items of clinical biochemistry. Internal quality control and external quality assessment were used to determine the uncertainty and standard uncertainty for the 23 items detected by Hitachi 7600 automatic biochemical analyzer. The uncertainties met the requirements of CLIA'88 for allowable error before correction except those of Cl-, P, TCH and TG, and correction made those of P, TCH and TG satisfy the requirements. The top-down method contributes to the understanding of the uncertainty of clinical biochemical items, while further efforts have to be performed for the uncertainty assessment standard.

The characteristic of top-down attentional control of children with acute stress disorder / 中华行为医学与脑科学杂志

Objective To investigate the characteristic of top-down attentional control of acute stress disorder children.Methods According to SCID-IV-TR,23 acute stress disorder children were chosen as the experinent group and 23 normal children were chosen as the control group.They were asked to perform a visual search task.Results (1) The reaction time of acute stress disorder children((1 253±158)ms) was significantly longer than normal children's((1 194± 146) ms) (P＜0.05).(2) The reaction time of valid condition((1 172± 144) ms)was significantly shorter than neutral condition ((1 229± 156) ms) and invalid condition ((1 269± 157) ms) (P＜0.05),there was no difference of reaction time between neutral condition((1 229± 156)ms) and invalid condition ((1 269±157)ms) (P＞0.05).(3) The reaction time of simple display condition((1 182±127)ms) was significantlv shorter than complex display condition ((1 264± 177)ms) (P＜0.01).Conclusion The performance of acute stress disorder children on top-down attentional control is less than normal children,the reason is that inhibiting capacity of acute stress disorder children is lower than normal children.It indicates that trauma event have negative influence on children's inhibiting capacity.

Application of“top-down” method in assessment of measurement uncertainty of biochemical detection indicators / 国际检验医学杂志

Objective To investigate the application of “top-down” method in assessment of measurement uncertainty of bio-chemical detection indicators .Methods The assessment data of internal quality control and external quality and “top-down”method were used to assess the precision and accuracy of 26 biochemical indicators ,and the two variables above were combined to calculate the measurement uncertainty .Results Uncertainty of 18 biochemical indicators was compatible with the target uncertainty ,ac-counting for approximately 69 .2% of all assessment projects .Five indicators ,such as TBIL ,albumin ,CK ,calcium and magnesium , was not compatible with the target uncertainty ,accounting for approximately 19 .2% of all assessment projects .Conclusion The“top-down” method is effective and feasible for assessment of measurement uncertainty of biochemical detection indicators .