The effect of real word stimuli versus non-word stimuli on oral diadochokinetic rates across the life span: An item discrimination analysis.

BACKGROUND: Diadochokinetic (DDK) rate tasks are extensively used in the evaluation of speech disorders; however, it is unclear how the different types of speech stimuli affect DDK rate performance. AIMS: To investigate the effect of age, gender and type of stimuli (non-words versus real words) on the DDK rates in individuals across the lifespan and to provide normative data for Greek. Also to examine the discrimination ability of the speech DDK stimuli administered (non-words and real words) based on a dual DDK assessment protocol using a polytomous item response theory (IRT) model. METHODS & PROCEDURE: The participants were 1747 monolingual Greek speakers (376 children, aged 4-17 years; and 1371 adults, aged 18-90+ years). All participants had normal hearing acuity which allowed them to understand and follow instructions. Participants with a medical condition or a language disorder which would affect DDK rate performance were excluded from the study. The time-by-count method was used, and all participants had to repeat as accurately and fast as possible: (1) four disyllabic non-words (/'gaba/, /'taka/, /'kata/, /'baga/), (2) four disyllabic real words (/'kapa/, /'tapa/, /ka'la/, /'paka/) and (3) two trisyllabic non-words (/'pataka/, /'badaga/). All responses were recorded and the speech samples that did not include at least 5 s of correct repetitions were excluded from the analysis. OUTCOMES & RESULTS: Age affected significantly DDK rates with performance increasing gradually until approximately the age of 40 and then gradually decreasing. Gender had no effect. Overall, there was a significant advantage of disyllabic real word stimuli over disyllabic non-word stimuli and of trisyllabic non-word stimuli over disyllabic non-word stimuli on DDK rates performance. IRT analysis suggested that the data fit the polytomous model reasonably well and all DDK stimuli (real words and non-words) showed a strong relationship (loadings > 0.50) with the latent trait. CONCLUSIONS & IMPLICATIONS: The current study complements prior research which supports that age and type of stimuli significantly affect DDK rates performance. It is the first study, that testifies to the benefit of real-word stimuli over non-word stimuli on DDK rates across the lifespan in a large representative sample. The implementation of IRT analysis provides empirical evidence about the discrimination ability of the DDK stimuli administered and confirms the reliability of this dual DDK assessment protocol. These findings are valuable for clinicians who work with motor speech disorders. WHAT THIS PAPER ADDS: What is already known on this subject Age, type of stimuli (real words versus non-words) and language significantly affect DDK rates performance. Current research strongly suggests the administration of language-specific norms since language-dependent features seem to have a noteworthy effect on the DDK rates, but scarce evidence exists about the discriminatory ability of the DDK speech stimuli commonly administered. What this study adds to the existing knowledge Conflicting findings have been reported about the effect of different types of DDK speech stimuli (real words and non-words) but no study to date has evaluated their discriminatory abilities. The current study is the first to implement a polytomous IRT model to examine this issue. This is also the first study to attempt an investigation of the effect of types of stimuli (real words versus non-words) on a large representative sample across the lifespan (4-90+ years) and to provide normative data for Greek. What are the practical and clinical implications of this work? The present study offers concrete evidence about the advantage of real-word stimuli over non-word stimuli in Greek, as well as normative data for the Greek-speaking populations. Moreover, the IRT analysis testifies to the discriminatory ability of real-word and non-word stimuli affirming the reliability of the present dual DDK assessment protocol as a psychometrically sound measure of DDK ability. The above has significant value for clinicians who work with individuals with motor speech disorders as the protocol can help them with the diagnosis and differential diagnosis of motor speech disorders.

Speed of Pitch Change in People with Parkinson's Disease: A Pilot Study

Objective: To examine laryngeal maximum performance through a novel pitch diadochokinetic (DDK) task in people with Parkinson's disease (PD) and healthy controls. Methods: This exploratory pilot study included a total of eight people with PD (seven male and one female) and eight healthy controls. Participants were instructed to rapidly transition or alternate between a chosen comfortable low and high pitch and were instructed to complete the task as a pitch glide. An Auditory Sawtooth Waveform Inspired Pitch Estimator-Prime model was used to first extract the pitch contour and then a customized MATLAB algorithm was used to compute and derive measures of pitch range and pitch slope. Results: Pitch range and slope were reduced in some participants with PD. Effects of age and disease duration were observed in people with PD: reductions in both pitch measures with increase in age and disease duration. Conclusions: A novel pitch DDK task may supplement the conventional laryngeal DDK task in the evaluation and treatment of motor speech and voice disorders. Individual variability analysis may provide specific diagnostic and therapeutic insights for people with PD.

Objetivo: Examinar el máximo rendimiento laríngeo a través de una novedosa tarea diadococinética de tono (DDK, por sus siglas en inglés) en personas con enfermedad de Parkinson (EP) y controles sanos. Métodos: Este estudio piloto exploratorio incluyó un total de ocho personas con EP (siete hombres y una mujer) y ocho controles sanos. Se instruyó a los participantes para que hicieran una transición rápida o alternaran entre un tono bajo y uno alto que les resultara cómodo y se les indicó que completaran la tarea como un deslizamiento de tono. Se utilizó un modelo de Estimador de Tono Inspirado en la Forma de Onda de Diente de Sierra Auditiva-Prime para extraer primero el contorno del tono y luego se utilizó un algoritmo MATLAB personalizado para calcular y derivar medidas de rango de tono y pendiente de tono. Resultados: El rango y la pendiente de tono se redujeron en algunos participantes con EP. Se observaron efectos de la edad y la duración de la enfermedad en personas con EP: reducciones en ambas medidas de tono con el aumento de la edad y la duración de la enfermedad. Conclusiones: Una nueva tarea de DDK de tono podría complementar la tarea DDK laríngea convencional en la evaluación y el tratamiento de trastornos motores del habla y de la voz. El análisis de la variabilidad individual podría proporcionar información específica de diagnóstico y terapéutica para personas con EP.

DBF4 Dependent Kinase Inhibition Suppresses Hepatocellular Carcinoma Progression and Potentiates Anti-Programmed Cell Death-1 Therapy.

The progression of hepatocellular carcinoma (HCC) remains a huge clinical challenge, and elucidation of the underlying molecular mechanisms is critical to develop effective therapeutic strategy. Dumbbell former 4 (DBF4) complexes with cell division cycle 7 (CDC7) to form DBF4-dependent kinase (DDK), playing instrumental roles in tumor cell survival, whereas its roles in HCC remain elusive. This study revealed that DBF4 expression was upregulated in HCC and constituted an independent prognostic factor of patient survival. We identified p65 as an upstream inducer which increased DBF4 expression by directly binding to its promoter. DBF4 accelerated HCC cell proliferation and tumorigenesis in vitro and in vivo. Mechanistically, DBF4 complexed with CDC7 to bind to the coiled coil domain of STAT3 and activate STAT3 signaling through XPO1-mediated nuclear exportation. Notably, p65 enhanced the nuclear transport of DDK and DDK-STAT3 interaction by transcriptionally upregulating XPO1. DBF4 expression positively correlated with activated STAT3 and XPO1 in HCC tissues. Furthermore, combining DDK inhibitor XL413 with anti-PD-1 immunotherapy dramatically suppressed HCC growth and prolonged the survival of HCC-bearing mouse. Our findings reveal that DDK activates STAT3 pathway and facilitates HCC progression, and demonstrate the proof of the concept of targeting DDK to improve the efficacy of HCC immunotherapy.

Oral diadochokinetic production in children with typical speech development and speech-sound disorders.

BACKGROUND: AIMS: To investigate the developmental trajectory of the rate and perceptual assessment of oral diadochokinesis (DDK) in typically developing children compared with adults. Also to examine the characteristics of DDK productions in children with speech sound disorders (SSD) and the relationship between DDK production and percentage of consonants correct (PCC). METHODS & PROCEDURES: Participants were 316 typically developing children and 90 children with SSD from 3 to 9 years old, as well as 20 adults with normal speech. The mono-, bi- and trisyllabic nonsense strings containing Korean tense consonants and the vowel [a] were used for DDK tasks. The number of iterations per s was measured as the DDK rate for each stimulus. The perceptual assessment of DDK productions was also performed for regularity, accuracy and rate. OUTCOMES & RESULTS: The DDK rates increased throughout childhood, but the oldest children, 9-year-olds in the current study, did not achieve adult-like rates for all mono- and trisyllabic strings. Children with SSD also did not show significant differences from typically developing children when the DDK productions were analysed using only accurate tokens. The PCC of children with SSD showed higher correlations with regularity, accuracy and rate of perceptual ratings than the timed DDK rate. CONCLUSIONS & IMPLICATIONS: This study highlighted the fact that the comprehensive evaluation of DDK productions may provide even more useful information about children's oral motor skills. WHAT THIS PAPER ADDS: What is already known on the subject Rates of DDK reflect the motor skills of the articulatory systems independently of phonological skills; therefore, the tasks are widely used in the diagnostic evaluations of speech disorders in both children and adult populations. However, a substantial number of studies have questioned the validity and usefulness of DDK rates for evaluating speech abilities. Also, the literature suggested that the measure of DDK rate alone does not provide a clear and useful indication of children's oral motor skills. DDK tasks should be analysed in terms of accuracy and consistency as well as rate. What this paper adds to the existing knowledge The literature reporting normative DDK performance has mainly been based on English speakers. As different consonants have different temporal characteristics, the linguistic and segmental features of DDK tasks can impact the DDK rate. This study established a norm for DDK rate for Korean-speaking children and investigated the developmental trajectory of DDK performance in typically developing children compared with adults. This study suggested that the comprehensive evaluation of DDK productions may provide even more useful information about children's oral motor skills by examining the characteristics of DDK productions in children with SSD. What are the potential or actual clinical implications of this work? This study provided normative data of young Korean-speaking children aged 3-9 years. Normative data in children under 5 years of age are valuable given that the majority of children referred for speech difficulty assessments are between 3 and 5 years of age, but only a few studies have provided the normative data in young children. This study showed that many children could not complete DDK tasks correctly and provided additional support for the notion that other aspects of DDK performance, including accuracy and regularity, may yield more useful diagnostic indications than timed DDK rates alone.

Speech and Nonspeech Parameters in the Clinical Assessment of Dysarthria: A Dimensional Analysis.

Nonspeech (or paraspeech) parameters are widely used in clinical assessment of speech impairment in persons with dysarthria (PWD). Virtually every standard clinical instrument used in dysarthria diagnostics includes nonspeech parameters, often in considerable numbers. While theoretical considerations have challenged the validity of these measures as markers of speech impairment, only a few studies have directly examined their relationship to speech parameters on a broader scale. This study was designed to investigate how nonspeech parameters commonly used in clinical dysarthria assessment relate to speech characteristics of dysarthria in individuals with movement disorders. Maximum syllable repetition rates, accuracies, and rates of isolated and repetitive nonspeech oral-facial movements and maximum phonation times were compared with auditory-perceptual and acoustic speech parameters. Overall, 23 diagnostic parameters were assessed in a sample of 130 patients with movement disorders of six etiologies. Each variable was standardized for its distribution and for age and sex effects in 130 neurotypical speakers. Exploratory Graph Analysis (EGA) and Confirmatory Factor Analysis (CFA) were used to examine the factor structure underlying the diagnostic parameters. In the first analysis, we tested the hypothesis that nonspeech parameters combine with speech parameters within diagnostic dimensions representing domain-general motor control principles. In a second analysis, we tested the more specific hypotheses that diagnostic parameters split along effector (lip vs. tongue) or functional (speed vs. accuracy) rather than task boundaries. Our findings contradict the view that nonspeech parameters currently used in dysarthria diagnostics are congruent with diagnostic measures of speech characteristics in PWD.

Analysis of the expression and prognostic significance of DDK complex in Hepatocarcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) remains one of the most common and lethal malignancies worldwide. Although DBF4-dependent kinase (DDK) complex composed of CDC7 kinase and its regulatory subunit DBF4 has been shown to be overexpressed in primary tumors and promotes tumor development, while its role and prognostic value in HCC remain largely unknown. In the present study, the expression of DBF4 and CDC7 and their relationship with clinical characteristics were comprehensively analyzed. METHODS: The mRNA expression profiles of HCC and the corresponding clinical data of HCC patients were downloaded from TCGA and GEO databases, respectively. The differences in DBF4 and CDC7 expression in tumor tissues and adjacent normal tissues were analyzed. HCC-derived tissue microarray (TMA) was used to evaluate and score the expression of CDC7 by immunohistochemistry (IHC) staining. The Kaplan-Meier method and the Cox regression method were used to analyze the relationship between overall survival and clinical characteristics of the patients. Gene set enrichment analysis (GSEA) was used to analyze the pathway enrichment of DBF4 and CDC7. RESULTS: DBF4 and CDC7 had similar expression patterns in HCC patients. Detailly, compared with adjacent tissues, both mRNA and protein of DBF4 and CDC7 were significantly higher in HCC, and their expression was positively correlated with AJCC_T stage, clinical stage and G stage (grade) of liver cancer patients, and higher DBF4 or CDC7 expression predicted a worse prognosis in HCC patients with shorter overall survival (OS), recurrence-free survival (RFS), disease-specific survival (DSS) and progress-free survival (PFS). Cox regression analysis suggested that both DBF4 and CDC7 were independent risk factors for the prognosis of HCC patients in TCGA dataset. GSEA suggested that both DBF4 and CDC7 were positively correlated with cell cycle and DNA replication. Finally, the prognostic value of CDC7 was furtherly confirmed by TMA-based IHC staining results. CONCLUSIONS: Our study showed that DDK complex was significantly increased in HCC. Both DBF4 and CDC7 may be potential diagnostic and prognostic markers for HCC, and high expression of DDK members predicts a worse prognosis in patients with HCC, which may be associated with high tumor cell proliferation rate.

Novel insights into the roles of Cdc7 in response to replication stress.

Cdc7 and its regulator Dbf4 (Dbf4-dependent kinase; DDK) form an essential complex due to its function in replication initiation, which is carried out by phosphorylating different residues at the helicase MCM during the G1/S transition. In response to replication stress, late origins are inhibited to prevent cell cycle progression until the problems are resolved. In yeast, this inhibition is partially achieved by attenuating DDK activity. In addition, evidence from yeast to human shows that Cdc7 is required for a successful DNA damage response by coordinating multiple processes dealing with replication stress (replication checkpoint, DNA damage tolerance and break-induced replication) through mechanisms that go beyond its role in origin activation. These studies reveal the importance of getting a better understanding of the spatiotemporal regulation of DDK. Here, we will discuss how DDK operates in these processes and its putative role in controlling the activity of replication and repair factors at specific nuclease-resistant nucleoprotein scaffolds.

DDK promotes DNA replication initiation: Mechanistic and structural insights.

DNA replication initiation in eukaryotes is tightly regulated through two cell-cycle specific processes, replication licensing to install inactive minichromosome maintenance (MCM) double-hexamers (DH) on origins in early G1 phase and origin firing to assemble and activate Cdc45-Mcm2-7-GINS (CMG) helicases upon S phase entry. Two kinases, cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), are responsible for driving the association of replication factors with the MCM-DH to form CMG helicases for origin melting and DNA unwinding and eventually replisomes for bi-directional DNA synthesis. In recent years, cryo-electron microscopy studies have generated a collection of structural snapshots for the stepwise assembly and remodeling of the replication initiation machineries, creating a framework for understanding the regulation of this fundamental process at a molecular level. Very recent progress is the structural characterization of the elusive MCM-DH-DDK complex, which provides insights into mechanisms of kinase activation, substrate recognition and selection, as well as molecular role of DDK-mediated MCM-DH phosphorylation in helicase activation.

WEE1 inhibition augments CDC7 (DDK) inhibitor-induced cell death in Ewing sarcoma by forcing premature mitotic entry and mitotic catastrophe.

Ewing sarcoma is an aggressive childhood cancer for which treatment options remain limited and toxic. There is an urgent need for the identification of novel therapeutic strategies. Our group has recently shown that Ewing cells rely on the S-phase kinase CDC7 (DDK) to maintain replication rates and cell viability and that DDK inhibition causes an increase in the phosphorylation of CDK1 and a significant delay in mitotic entry. Here, we expand on our previous findings and show that DDK inhibitor-induced mitotic entry delay is dependent upon WEE1 kinase. Specifically, WEE1 phosphorylates CDK1 and prevents mitotic entry upon DDK inhibition due to the presence of under-replicated DNA, potentially limiting the cytotoxic effects of DDK inhibition. To overcome this, we combined the inhibition of DDK with the inhibition of WEE1 and found that this results in elevated levels of premature mitotic entry, mitotic catastrophe, and apoptosis. Importantly, we have found that DDK and WEE1 inhibitors display a synergistic relationship with regards to reducing cell viability of Ewing sarcoma cells. Interestingly, the cytotoxic nature of this combination can be suppressed by the inhibition of CDK1 or microtubule polymerization, indicating that mitotic progression is required to elicit the cytotoxic effects. This is the first study to display the potential of utilizing the combined inhibition of DDK and WEE1 for the treatment of cancer. We believe this will offer a potential therapeutic strategy for the treatment of Ewing sarcoma as well as other tumor types that display sensitivity to DDK inhibitors.

Dbf4-Cdc7 (DDK) Inhibitor PHA-767491 Displays Potent Anti-Proliferative Effects via Crosstalk with the CDK2-RB-E2F Pathway.

Precise regulation of DNA replication complex assembly requires cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK) activities to activate the replicative helicase complex and initiate DNA replication. Chemical probes have been essential in the molecular analysis of DDK-mediated regulation of MCM2-7 activation and the initiation phase of DNA replication. Here, the inhibitory activity of two distinct DDK inhibitor chemotypes, PHA-767491 and XL-413, were assessed in cell-free and cell-based proliferation assays. PHA-767491 and XL-413 show distinct effects at the level of cellular proliferation, initiation of DNA replication and replisome activity. XL-413 and PHA-767491 both reduce DDK-specific phosphorylation of MCM2 but show differential potency in prevention of S-phase entry. DNA combing and DNA replication assays show that PHA-767491 is a potent inhibitor of the initiation phase of DNA replication but XL413 has weak activity. Importantly, PHA-767491 decreased E2F-mediated transcription of the G1/S regulators cyclin A2, cyclin E1 and cyclin E2, and this effect was independent of CDK9 inhibition. Significantly, the enhanced inhibitory profile of PHA-767491 is mediated by potent inhibition of both DDK and the CDK2-Rb-E2F transcriptional network, that provides the molecular basis for its increased anti-proliferative effects in RB+ cancer cell lines.

DDK: The Outsourced Kinase of Chromosome Maintenance.

The maintenance of genomic stability during the mitotic cell-cycle not only demands that the DNA is duplicated and repaired with high fidelity, but that following DNA replication the chromatin composition is perpetuated and that the duplicated chromatids remain tethered until their anaphase segregation. The coordination of these processes during S phase is achieved by both cyclin-dependent kinase, CDK, and Dbf4-dependent kinase, DDK. CDK orchestrates the activation of DDK at the G1-to-S transition, acting as the 'global' regulator of S phase and cell-cycle progression, whilst 'local' control of the initiation of DNA replication and repair and their coordination with the re-formation of local chromatin environments and the establishment of chromatid cohesion are delegated to DDK. Here, we discuss the regulation and the multiple roles of DDK in ensuring chromosome maintenance. Regulation of replication initiation by DDK has long been known to involve phosphorylation of MCM2-7 subunits, but more recent results have indicated that Treslin:MTBP might also be important substrates. Molecular mechanisms by which DDK regulates replisome stability and replicated chromatid cohesion are less well understood, though important new insights have been reported recently. We discuss how the 'outsourcing' of activities required for chromosome maintenance to DDK allows CDK to maintain outright control of S phase progression and the cell-cycle phase transitions whilst permitting ongoing chromatin replication and cohesion establishment to be completed and achieved faithfully.

Diadochokinetic rates in healthy young and elderly Greek-speaking adults: The effect of types of stimuli.

BACKGROUND: Diadochokinetic rates tasks are frequently used for the assessment of diadochokinesia (DKK) in young and elderly adults. However, there is scarce research on healthy elderly adults over 65 years old, and little is known about the effect of different types of stimuli (non-words/real words) in this specific population. Furthermore, the current research supports significant language variations, highlighting the need for language-specific norms. AIMS: To investigate the effect of age, gender and type of stimuli (non-words versus real words) in DDK rates in healthy elderly adults of over 65 years of age, and to provide normative data for the Greek language. METHODS & PROCEDURES: The participants were 791 healthy monolingual Greek-speaking adults (531 adults, aged 20-39 years; 157 participants aged 65-74 years; and 103 participants aged over 75 years). All participants were monolingual speakers of Greek and had normal hearing acuity, which allowed them to understand and follow instructions. Participants with a medical condition, which would affect DDK rates' performance, were excluded from the study. The time-by-count method was used, and all participants had to repeat as accurately and fast as possible: (1) four disyllabic non-words (/'gaba/, /'taka/, /'kata/, /'baga/); (2) four disyllabic real words (/'kapa/, /'tapa/, /ka'la/, /'paka/); and (3) two trisyllabic non-words (/'pataka/, /'badaga/). All responses were recorded and the speech samples that did not include at least 5 s of correct repetitions were excluded from the analysis. OUTCOMES & RESULTS: Age affected DDK rates significantly, with older adults achieving slower DDK rates for all speech stimuli (non-words/real words). Gender did not have an effect on the performance of DDK rates. The type of speech stimuli affected DDK rates significantly for all age groups. Analytically, trisyllabic non-word stimuli were articulated more slowly than disyllabic non-word stimuli, and real words were produced faster than non-words. A linear regression analysis revealed that only the repetition of non-words predicted 68.4% of the performance on the repetition of trisyllabic non-words. CONCLUSIONS & IMPLICATIONS: The above results complement prior research, which supports that real word stimuli yield faster performance than non-word stimuli. Clinicians should keep in mind that age, language and type of stimuli (non-words/real words) affect significantly the performance of DDK rates, as well as the fact that different types of stimuli tap distinct underlying levels of speech. The current research highlights the need for language-specific norms for different populations. WHAT THIS PAPER ADDS: What is already known on the subject DDK rates are significantly affected by the types of stimuli and language used. Moreover, the normal ageing process decreases performance in terms of DDK rates, but scarce evidence exists for healthy elderly adults over 65 years old. What this paper adds to existing knowledge Most studies have examined DDK rates in healthy elderly people with restricted samples and using non-word stimuli. The current study administered different types of stimuli (non-words/words) in a large sample of healthy elderly participants. This is also the first study to attempt to provide DDK normative data for this population in the Greek language. What are the potential or actual clinical implications of this work? The results of this study strongly suggest that clinicians should bear in mind the significant impact age and language have on performance in terms of DDK rates, especially when normative data are not available for a certain language or age group. Furthermore, non-word and real-word stimuli cannot be used interchangeably since they tap into distinct underlying levels of speech, thus providing clinicians with useful information about the level of breakdown and the proper treatment plan.

Temporal control of late replication and coordination of origin firing by self-stabilizing Rif1-PP1 hubs in Drosophila.

In the metazoan S phase, coordinated firing of clusters of origins replicates different parts of the genome in a temporal program. Despite advances, neither the mechanism controlling timing nor that coordinating firing of multiple origins is fully understood. Rif1, an evolutionarily conserved inhibitor of DNA replication, recruits protein phosphatase 1 (PP1) and counteracts firing of origins by S-phase kinases. During the midblastula transition (MBT) in Drosophila embryos, Rif1 forms subnuclear hubs at each of the large blocks of satellite sequences and delays their replication. Each Rif1 hub disperses abruptly just prior to the replication of the associated satellite sequences. Here, we show that the level of activity of the S-phase kinase, DDK, accelerated this dispersal program, and that the level of Rif1-recruited PP1 retarded it. Further, Rif1-recruited PP1 supported chromatin association of nearby Rif1. This influence of nearby Rif1 can create a "community effect" counteracting kinase-induced dissociation such that an entire hub of Rif1 undergoes switch-like dispersal at characteristic times that shift in response to the balance of Rif1-PP1 and DDK activities. We propose a model in which the spatiotemporal program of late replication in the MBT embryo is controlled by self-stabilizing Rif1-PP1 hubs, whose abrupt dispersal synchronizes firing of associated late origins.

Comportamiento de los parámetros diadococinéticos orales en escolares de primero básico y su relación con el nivel sociocultural y el desempeño fonético-fonológico / Behavior of the oral diadochokinetic parameters in primary school students and its relationship with the sociocultural level and phonetic-phonological performance

El objetivo de esta investigación es evaluar el comportamiento de los parámetros diadococinéticos orales en una población de escolares de primero básico, pertenecientes a dos niveles socioculturales y con diferente desempeño fonético-fonológico. Para alcanzar este objetivo se evaluó el rendimiento diadococinético oral de los participantes a través de la repetición monosilábica de [pa], [t̪a] y [ka] utilizando el método de emisión de sílabas en un tiempo determinado. El análisis de las emisiones se llevó a cabo con el programa Motor Speech Profile, el cual entregó los valores de medición para cinco parámetros diadococinéticos (DDKavp, DDKavr, DDKcvp, DDKjit, DDKcvi). Por otra parte, el desempeño fonético-fonológico fue analizado a través de la Pauta de Clasificación de Ajustes Fonético-Fonológicos (CLAFF). Los resultados obtenidos mostraron diferencias significativas entre ambos grupos socioculturales solo para los parámetros DDKcvp/%/ y DDKjit/%/, mientras que el resto de los parámetros diadococinéticos se comportó de manera similar. El grupo de niños del nivel sociocultural bajo tuvo una mayor variabilidad de la tasa DDK y mayor porcentaje de perturbaciones. Se observaron relaciones significativas entre algunos ajustes fonéticos-fonológicos y algunos parámetros diadococinéticos.

The aim of this research is to evaluate the behavior of the oral diadochokinetic parameters in first grade students, who belong to two different sociocultural environments and have different phonetic-phonological performance. To reach this objective, the oral diadochokinetic parameters were evaluated through monosyllabic repetition of [pa], [t̪a] and [ka] using the syllable emission method in a specific time. The syllable emission analysis was carried out through the Motor Speech Profile program, which provided with measurement values for five diadochokinetic parameters (DDKavp, DDKavr, DDKcvp, DDKjit, DDKcvi). On the other hand, the phonetic-phonological performance was analyzed through the Classification of Phonetic and Phonological Adjustments (CLAFF). The results showed differences between both sociocultural groups only for the parameters DDKcvp/%/ y DDKjit/%/, while the other diadochokinetic parameters behaved in a similar way. The low sociocultural children group had a higher variability in the DDK parameters and a higher percentage of disturbances. Significant relations could be seen between some phonetic-phonological adjustments and some diadochokinetic parameters.

The role of DDK and Treslin-MTBP in coordinating replication licensing and pre-initiation complex formation.

Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.

Evaluating rate and accuracy of real word vs. non-word diadochokinetic productions from childhood to early adulthood in Hebrew speakers.

BACKGROUND: Oral-Diadochokinesis (oral-DDK) tasks measure how quickly and accurately one can repeat a series of target sounds. Thus, they are a popular tool for evaluating oral-motor skills for individuals with various speech disorders. Typically, oral-DDK tasks involve rapid repetition of non-words. For several populations (e.g., young children, older adults), it has been suggested that repetitions of real words may be more suitable, commonly resulting in faster rates. Yet, the literature is either silent or inconsistent regarding this real-word repetition advantage for other age groups, from preschoolers to young adults. It is not clear whether performance accuracy is affected as well. Specifically, for Hebrew speakers, this data is missing. AIMS: The goal of this study was to compare rate and accuracy for non-word and real-word repetition, in four groups of Hebrew-speaking individuals; preschoolers (5 years old), younger elementary school children (7 years old), adolescents (15 years old) and young adults (25 years old). Secondary goals were to provide a developmental pattern for oral-DDK rates for Hebrew speakers, and to compare it to the English norms. METHODS & PROCEDURES: All participants (n=150) had typical speech and language development. They were asked to repeat "pataka" (non-word) and "bodeket" (Hebrew real word) as quickly and accurately as possible for 10 sec. Production rates (syllables per second) and accuracy (on a 5-point scale) were measured. OUTCOMES & RESULTS: As expected, oral-DDK rates gradually increased with age, with similar rates for both real- and non-words. Accuracy scores were higher for real- than non-word repetition, across all age groups. For the group of school-age children, the Hebrew rates differed from the English ones. CONCLUSIONS & IMPLICATIONS: A real-word repetition advantage was documented only for repetition accuracy, but not for rate. These findings can be explained as each stimulus involves different demands on an individual's neuro-motor and linguistic processing abilities. Further research using real- and non-word tasks should be conducted with clinical populations to assess whether both procedures could assist in differential diagnosis between various speech disorders. Finally, the large differences between children of different ages, as well as the apparent rate differences between Hebrew and English, highlight the need to create age- and language-sensitive norms.

Evaluation of oro-phonatory development and articulatory diadochokinesis in a sample of Italian children using the protocol of Robbins & Klee.

PURPOSE: The Italian version (Granocchio et al., 2019) of the protocol proposed by Robbins and Klee (1987) allows the assessment of structure of the vocal tract, oromotor and oro-phonatory ability, and articulatory diadochokinesis in children. The aim of this study was to collect the first normative sample of Italian children. METHODS: We measured the total structural score (TSS), total functional score (TFS), oral function score (OFS), phonatory function score (PFS), maximum phonation time (MPT), speed of monosyllable repetition (SMR), and speed of polysyllable repetition (SPR) in 191 typically developing Italian children aged 2.6-6.11 years. RESULTS: Like the finding observed in the original protocol, there were no significant age-related changes in TSS, but the correlation was observed for TFS, OFS, PFS, MPT, SMR and SPR. The Inter-observer agreement was "good" or "excellent" for all scores except for SPR that was "moderate". CONCLUSIONS: The increase in oro-motor, oro-phonatory and diadochokinetic abilities confirmed the progressive maturation of these functions with age. The protocol can therefore be considered a useful instrument to classify speech sound disorders (SSDs) by excluding alterations in anatomical structures and evaluate the motor impairment. This normative sample of Italian children allows to use these measures for diagnostic purposes in young Italian speakers.

Human DDK rescues stalled forks and counteracts checkpoint inhibition at unfired origins to complete DNA replication.

Eukaryotic genomes replicate via spatially and temporally regulated origin firing. Cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK) promote origin firing, whereas the S phase checkpoint limits firing to prevent nucleotide and RPA exhaustion. We used chemical genetics to interrogate human DDK with maximum precision, dissect its relationship with the S phase checkpoint, and identify DDK substrates. We show that DDK inhibition (DDKi) leads to graded suppression of origin firing and fork arrest. S phase checkpoint inhibition rescued origin firing in DDKi cells and DDK-depleted Xenopus egg extracts. DDKi also impairs RPA loading, nascent-strand protection, and fork restart. Via quantitative phosphoproteomics, we identify the BRCA1-associated (BRCA1-A) complex subunit MERIT40 and the cohesin accessory subunit PDS5B as DDK effectors in fork protection and restart. Phosphorylation neutralizes autoinhibition mediated by intrinsically disordered regions in both substrates. Our results reveal mechanisms through which DDK controls the duplication of large vertebrate genomes.

Cell-cycle phospho-regulation of the kinetochore.

The kinetochore is a mega-dalton protein assembly that forms within centromeric regions of chromosomes and directs their segregation during cell division. Here we review cell cycle-mediated phosphorylation events at the kinetochore, with a focus on the budding yeast Saccharomyces cerevisiae and the insight gained from forced associations of kinases and phosphatases. The point centromeres found in the budding yeast S. cerevisiae are one of the simplest such structures found in eukaryotes. The S. cerevisiae kinetochore comprises a single nucleosome, containing a centromere-specific H3 variant Cse4CENP-A, bound to a set of kinetochore proteins that connect to a single microtubule. Despite the simplicity of the budding yeast kinetochore, the proteins are mostly homologous with their mammalian counterparts. In some cases, human proteins can complement their yeast orthologs. Like its mammalian equivalent, the regulation of the budding yeast kinetochore is complex: integrating signals from the cell cycle, checkpoints, error correction, and stress pathways. The regulatory signals from these diverse pathways are integrated at the kinetochore by post-translational modifications, notably phosphorylation and dephosphorylation, to control chromosome segregation. Here we highlight the complex interplay between the activity of the different cell-cycle kinases and phosphatases at the kinetochore, emphasizing how much more we have to understand this essential structure.

Oral-diadochokinetic rates among healthy Malaysian-Mandarin speakers: A cross linguistic comparison.

PURPOSE: This study examined the effects of non-word versus real word, age, and gender on oral-DDK rates among healthy Malaysian-Mandarin speakers. Comparison between non-word of Malaysian-Mandarin and Hebrew speakers was examined. METHOD: One-hundred and seventeen speakers (18-83 years old, 46% men) were audio-recorded while performing non-word (repetition of "pataka") and real-word oral-DDK tasks ("butter cake" and " ([pha4tha1khan4])"). The number of syllables produced in 8 seconds was counted from the audio recording to derive the oral-DDK rates. A MANOVA was conducted to compare the rates between age groups (young = 18-40 years, n = 56; middle = 41-60 years, n = 39; older = 61-83 years, n = 22) and gender. In a second analysis, "pataka" results were compared between this study and previous findings with Hebrew speakers. RESULT: No gender effects were found. However, rates significantly decreased with age (p < 0.001). Repetition of real words was faster than that of non-words - English words (5.55 ± 1.19 syllables/s) > non-words (5.29 ± 1.23) > Mandarin words (4.91 ± 1.13). Malaysian-Mandarin speakers performed slower than Hebrew speakers on "pataka" task. CONCLUSION: Aging has a large impact on oromotor functions, indicating that speech-language pathologists should consider using age-adjusted norms.