Validation of Attention Deficit Hyperactivity Disorder Diagnostic Scale for Children.

BACKGROUND: There is no valid Attention Deficit Hyperactivity Disorder diagnostic tool to fit Nepalese culture and language till date. Current study is intended to develop and validate the Attention Deficit Hyperactivity Disorder scale for children in Nepal. METHODS: Mixed method study was conducted with 840 samples (i.e. children with Attention Deficit Hyperactivity Disorder =356, Anxiety =128 and General Population=356).Items generation, scale development and scale evaluation were the three consecutive steps followed to develop and validate the scale.Children with Attention Deficit Hyperactivity Disorder (already met the Diagnostic and statistical Manual-5 criteria) were further assessed by Kiddie-Schedule for Affective disorders and Schizophrenia (K-SADS-PL), Child and Adolescent Symptoms Inventory (CASI-5) to confirm the diagnosis and psychometric validation. Pilot studies were done for items clarity. Each data obtained from three comparison groups (Attention Deficit Hyperactivity Disorder , Anxiety and General Population) were included for standardization process where tests of dimensionality, reliability, validity,calculating norms (cut off) were doneas scale evaluation process. RESULTS: The final version of the scale had 21 items. Three sub-scales (Inattention, Impulsivity and Hyperactivity) were identified by using Principal Axis Factor Analysis.All factors showed strong statistically significant convergent validity and Discriminant validity Cronbach's alpha of each item is ? 0.91.As total score criteria, 38.5 is considered as the best cut-off point for this scale. CONCLUSIONS: By using systematic process, a valid and reliable Attention Deficit Hyperactivity Disorder diagnostic scale is being developed in Nepalese culture and language.

Tight binding of heme to Staphylococcus aureus IsdG and IsdI precludes design of a competitive inhibitor.

The micromolar equilibrium constants for heme dissociation from IsdG and IsdI reported in the literature call into question whether these enzymes are actually members of the iron-regulated surface determinant system of Staphylococcus aureus, which harvests heme iron from a host during infection. In order to address this question, the heme dissociation constants for IsdG and IsdI were reevaluated using three approaches. The heme dissociation equilibrium constants were measured using a UV/Vis absorption-detected assay analyzed with an assumption-free model, and using a newly developed fluorescence-detected assay. The heme dissociation rate constants were estimated using apomyoglobin competition assays. Analyses of the UV/Vis absorption data revealed a critical flaw in the previous measurements; heme is 99.9% protein-bound at the micromolar concentrations needed for UV/Vis absorption spectroscopy, which renders accurate equilibrium constant measurement nearly impossible. However, fluorescence can be measured for more dilute samples, and analyses of these data resulted in dissociation equilibrium constants of 1.4 ± 0.6 nM and 12.9 ± 1.3 nM for IsdG and IsdI, respectively. Analyses of the kinetic data obtained from apomyoglobin competition assays estimated heme dissociation rate constants of 0.022 ± 0.002 s-1 for IsdG and 0.092 ± 0.008 s-1 for IsdI. Based upon these data, and what is known regarding the post-translational regulation of IsdG and IsdI, it is proposed that only IsdG is a member of the heme iron acquisition pathway and IsdI regulates heme homeostasis. Furthermore, the nanomolar dissociation constants mean that heme is bound tightly by IsdG and indicates that competitive inhibition of this protein will be difficult. Instead, uncompetitive inhibition based upon a detailed understanding of enzyme mechanism is a more promising antibiotic development strategy.