Identification of N(G)-methylarginine residues in human heterogeneous RNP protein A1: Phe/Gly-Gly-Gly-Arg-Gly-Gly-Gly/Phe is a preferred recognition motif

Three sites of N(G),N(G)-arginine methylation have been located at residues 205, 217, and 224 in the glycine-rich, COOH-terminal one-third of the HeLa A1 heterogeneous ribonucleoprotein. Together with the previously determined dimethylated arginine at position 193 [Williams et al., (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 5666-5670], it is evident that all four sites fall within a span of sequence between residues 190 and 233 that contains multiple Arg-Gly-(Gly) sequences interspersed with phenylalanine residues. These RGG boxes have been postulated to represent an RNA binding motif [Kiledjian and Dreyfuss (1992) EMBO J. 11, 2655-2664]. Dimethylation of HeLa A1 appears to be quantitative at each of the four positions. Arginines 205 and 224 have been methylated in vitro by a nuclear protein arginine methyltransferase using recombinant (unmethylated) A1 as substrate. This suggests A1 may be an in vivo substrate for this enzyme. Examination of sequences surrounding the sites of methylation in A1 along with a compilation from the literature of sites that have been identified in other nuclear RNA binding proteins suggests a methylase-preferred recognition sequence of Phe/Gly-Gly-Gly-Arg-Gly-Gly-Gly/Phe, with the COOH-terminal flanking glycine being obligatory. Taken together with data in the literature, identification of the sites of A1 arginine methylation strongly suggests a role for this modification in modulating the interaction of A1 with nucleic acids.

Characterization of monoclonal antibody glycosylation: comparison of expression systems and identification of terminal alpha-linked galactose

CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG1) which recognizes the CDw52 antigen of human lymphocytes, and has been the subject of clinical trials for the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis. Peptide mapping by liquid chromatography-mass spectrometry was used to confirm the predicted amino acid sequences and profile glycosylation for two CAMPATH isotypes expressed in a murine myeloma cell line (NS0) and a single isotype expressed in both Chinese hamster ovary (CHO) and NS0 lines. The three major glycoforms identified in CAMPATH are fucosylated biantennary structures, containing zero, one, or two galactose residues. Glycosylation of the IgG1 form of CAMPATH expressed in CHO cells is consistent with normal human IgG. However, IgG1 and IgG4 expressed in NS0 cells include two potentially immunogenic glycoforms which contain either one or two nonreducing terminal alpha-linked galactose residues. Oligosaccharide structures were characterized by a combination of tandem mass spectrometry, methylation analysis, and exoglycosidase digestion. The strategy used here is designed to be widely applicable to recombinant glycoproteins.

Sequence, expression in Escherichia coli, and analysis of the gene encoding a novel intracellular protease (PfpI) from the hyperthermophilic archaeon Pyrococcus furiosus

A previously identified intracellular proteolytic activity in the hyperthermophilic archaeon Pyrococcus furiosus (I. I. Blumentals, A. S. Robinson, and R. M. Kelly, Appl. Environ. Microbiol. 56:1992-1998, 1990) was found to be a homomultimer consisting of 18.8-kDa subunits. Dissociation of this native P. furiosus protease I (PfpI) into a single subunit was seen by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) but only after trichloroacetic acid precipitation; heating to 95 degrees C in the presence of 2% SDS and 80 mM dithiothreitol did not dissociate the protein. The gene (pfpI) coding for this protease was located in genomic digests by Southern blotting with probes derived from the N-terminal amino acid sequence. pfpI was cloned, sequenced, and expressed in active form in Escherichia coli as a fusion protein with a histidine tag. The recombinant protease from E. coli showed maximum proteolytic activity at 95 degrees C, and its half-life was 19 min at this temperature. This level of stability was significantly below that previously reported for the enzyme purified by electroelution of a 66-kDa band from SDS-PAGE after extended incubation of cell extracts at 98 degrees C in 1% SDS (>30 h). The pfpI gene codes for a polypeptide of 166 amino acid residues lacking any conserved protease motifs; no protease activity was detected for the 18.8-kDa PfpI subunit (native or recombinant) by substrate gel assay. Although an immunological relationship of this protease to the eukaryotic proteasome has been seen previously, searches of the available databases identified only two similar amino acid sequences: an open reading frame of unknown function from Staphylococcus aureus NCTC 8325 (171 amino acid residues, 18.6 kDa, 41% identity) and an open reading frame also of unknown function in E. coli (172 amino acid residues, 18.8 kDa, 47% identity). Primer extension experiments with P. furiosus total RNA defined the 5' end of the transcript. There are only 10 nucleotides upstream of the start of translation; therefore, it is unlikely that there are any pre- or pro-regions associated with PfpI which could have been used for targeting or assembly of this protease. Although PfpI activity appears to be the dominant proteolytic activity in P. furiosus cell extracts, the physiological function of PfpI is unclear.

Purification and characterization of the constitutive nitric oxide synthase from human placenta

Human endothelial nitric oxide synthase (NOS) mRNA was detected in human placenta. In contrast, mRNAs for human neuronal NOS or for human inducible NOS were not detected in placenta. Subsequently, NOS was purified over 3800-fold from placental extract to greater than 80% homogeneity. A single band with an apparent molecular weight of 135 kDa was identified by [125I] calmodulin binding to proteins in a sodium dodecyl sulfate-polyacrylamide gel, which is consistent with the predicted size of the endothelial NOS. Furthermore, the sequence of eight internal peptides derived from this 135-kDa protein was identical to the published sequence of human endothelial NOS. As has been shown for all constitutive NOS isozymes, the purified NOS was absolutely dependent on calcium and calmodulin. NOS was also purified from human umbilical vein endothelial cells and, on the basis of similar kinetic parameters and dependence upon calcium and calmodulin, appeared to be the same as the purified placental NOS. Together, these data indicate that the placental NOS is the constitutive NOS isozyme from endothelial tissue.

Interactions of the A1 heterogeneous nuclear ribonucleoprotein and its proteolytic derivative, UP1, with RNA and DNA: evidence for multiple RNA binding domains and salt-dependent binding mode transitions

The 319-residue A1 heterogeneous nuclear ribonucleoprotein is the best studied of the group of major or core mammalian hnRNP proteins that bind pre-mRNA immediately following transcription. Circular dichroism studies suggest that binding of A1 and its proteolytic fragment, UP1 (residues 1-195), to nucleic acids results in an unstacking of the bases of poly(A). On the basis of poly[d(A-T)] and poly[r(A-U)] melting studies, both A1 and UP1 are helix-destabilizing proteins. Titrations of A1 and UP1 with poly(A), poly(U), and poly[d(T)] suggest that these two proteins do not bind with significant base specificity. A previous study indicated that A1, which contains a glycine-rich COOH terminus (residues 196-319) not present in UP1, binds cooperatively to polynucleotides while UP1 does not [Cobianchi et al. (1988) J. Biol. Chem. 263, 1063-1071]. Here we confirm this latter finding and demonstrate that the cooperativity parameter for A1 binding, which has a value of about 35 for binding to both single-stranded RNA and DNA, is insensitive to the NaCl concentration at least up to 0.4 M. In contrast to the cooperativity parameter, the occluded site size for A1 binding to RNA is salt dependent and increases from about 14 to 28 upon increasing the NaCl concentration from 25 to 250 mM. This variation in site size is best explained by assuming that A1 can interact with nucleic acids via at least two different binding modes. Both A1 and UP1 have higher affinity for single-stranded as opposed to double-stranded nucleic acids and bind preferentially to single-stranded RNA as compared to DNA. Comparative studies on the binding of A1 versus UP1 to poly[r(epsilon A)] demonstrate that in addition to cooperative protein/protein interactions, the glycine-rich COOH-terminal domain of A1 is also directly involved in protein/nucleic acid interactions.(ABSTRACT TRUNCATED AT 250 WORDS)

F sex factor encodes a single-stranded DNA binding protein (SSB) with extensive sequence homology to Escherichia coli SSB

We have determined the sequence of the gene encoding a single-stranded DNA (ss DNA) binding protein (SSB) from the Escherichia coli F sex factor and the amino acid sequence of the protein it encodes. The protein has extensive homology with E. coli SSB, particularly within its NH2-terminal region, where 87 of the first 115 amino acid residues are identical to those of the E. coli protein. We have previously shown that this portion of E. coli SSB contains the DNA binding region. The sequences diverge extensively in their COOH-terminal regions, although small areas of homology exist in several places. Six of the last seven amino acid residues of the two proteins are identical, which may have implications in terms of the direct interactions of these proteins with other proteins required for DNA replication, recombination, and repair. The coding region of the F plasmid ssf gene is 537 base pairs. The protein encoded by the gene contains 178 amino acids (one more than E. coli SSB) and has a calculated molecular weight of 19,505. Other than the presumptive Shine-Dalgarno sequence, the promoter and terminator regions of both genes are not similar. The most significant feature in this regard may be the lack of a region of dyad symmetry within the presumptive promoter of the F plasmid ssf gene as is found in the region of the presumptive E. coli ssb promoter. In this report the predicted secondary structures of both the F plasmid and E. coli SSB proteins are compared and the evolutionary significance of their sequence and structural similarities to the functional domains of the proteins are discussed.

Site-specific conjugation on serine right-arrow cysteine variant monoclonal antibodies

We have engineered a cysteine residue at position 442 (EU/OU numbering) in the third constant domain (C(H)3) of the heavy chain of several IgGs with different specificities, isoforms, and variants with the intent to introduce a site for chemical conjugation. The variants were expressed in NS0 mouse myeloma cells, where monomeric IgG is the major form and formation of aggregate was minimal. Monomeric IgG contained no free thiol; however, it was discovered that the engineered thiols were reversibly blocked and could be reduced under controlled conditions. Following reduction, reactive thiol was conjugated with a cysteine-specific bifunctional chelator, bromoacetyl-TMT to a humanized 323/A3 IgG4 variant. Conjugation had no significant effect on antibody affinity. To prove that the conjugation was site-specific, an antibody-TMT conjugate was labeled with lutetium-177 and subjected to peptide mapping followed by sequence analysis. Glu-C digestion demonstrated that 91% of the label was recovered in the COOH-terminal peptide fragment containing the engineered cysteine.

Relationship of genes encoding Ca2+/calmodulin-dependent protein kinase Gr and calspermin: a gene within a gene

Ca2+/calmodulin-dependent protein kinase enriched in cerebellar granule cells (CaM kinase Gr) is a neuronal calmodulin-dependent protein kinase whose purification and partial cloning from rat brain has been described. A combination of the polymerase chain reaction and cDNA library screening was used to determine the DNA sequence that encodes most of the remaining polypeptide sequence. The deduced amino acid sequence was confirmed by comparison with the peptide sequence from purified CaM kinase Gr. Analysis of this sequence indicated the presence of potential catalytic, regulatory, and association domains with 42% overall homology to the alpha subunit of another neuronal Ca2+/calmodulin-dependent protein kinase, CaM kinase II. The degree of homology within the catalytic domain was 58% with conservation of all invariant amino acids. The portion of sequence that extended from the hypothesized calmodulin-binding domain to the carboxyl terminus of the protein was identical at both the amino acid and nucleotide level to the noncatalytic, calmodulin-binding protein calspermin from rat testis. Screening a genomic library with a portion of the cDNA for CaM kinase Gr allowed the isolation of a genomic clone that contained at least 9 kilobases (kb) of the gene for CaM kinase Gr. Analysis of the sequence revealed that the coding sequences for calspermin were contained within the CaM kinase Gr gene and that alternative splicing of internal exons may lead to the formation of the two different proteins, CaM kinase Gr and calspermin.

Mapping the academic problem behaviors of adolescents with ADHD

This study possessed 2 aims: (a) to develop and validate a clinician-friendly measure of academic problem behavior that is relevant to the assessment of adolescents with attention deficit/hyperactivity disorder (ADHD) and (b) to better understand the cross-situational expression of academic problem behaviors displayed by these youth. Within a sample of 324 adolescents with the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision diagnosed ADHD (age M = 13.07, SD = 1.47), parent, teacher, and adolescent self-report versions of the Adolescent Academic Problems Checklist (AAPC) were administered and compared. Item prevalence rates, factorial validity, interrater agreement, internal consistency, and concurrent validity were evaluated. Findings indicated the value of the parent and teacher AAPC as a psychometrically valid measure of academic problems in adolescents with ADHD. Parents and teachers offered unique perspectives on the academic functioning of adolescents with ADHD, indicating the complementary roles of these informants in the assessment process. According to parent and teacher reports, adolescents with ADHD displayed problematic academic behaviors in multiple daily tasks, with time management and planning deficits appearing most pervasive. Adolescents with ADHD display heterogeneous academic problems that warrant detailed assessment prior to treatment. As a result, the AAPC may be a useful tool for clinicians and school staff conducting targeted assessments with these youth.

Cloning, sequence analysis, and overexpression of Escherichia coli folK, the gene coding for 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase

The gene coding for the Escherichia coli enzyme 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase has been cloned and sequenced. This gene, designated folK, codes for a protein of 159 amino acids, including an amino-terminal methionine. The protein was overexpressed in E. coli MC4100 by cloning the gene behind the lacUV5 promoter in a high-copy-number plasmid. The enzyme was purified to homogeneity. Amino-terminal analysis of the purified protein showed that the amino-terminal methionine had been removed. The compositional molecular mass (17,945 Da) was identical to the molecular mass determined by mass spectrometry. The enzyme was observed to have a large number of proline residues and migrated anomalously in sodium dodecyl sulfate-polyacrylamide gels, with an apparent molecular mass of 23,000 Da.

Identification of the active site nucleophile in nucleoside 2-deoxyribosyltransferase as glutamic acid 98

2'-Fluoro-2'-deoxyarabinonucleosides are time-dependent inhibitors of nucleoside 2-deoxyribosyltransferase. 2,6-Diamino-9-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-9H-purine (dFDAP) inhibited the enzyme by formation of a primary complex (Kd = 140 microM) that isomerized to a secondary complex with a first-order rate constant of 0.2 min-1. Inhibited enzyme contained stoichiometric amounts of covalently bound 2'-fluoro-2'-deoxyarabinosyl moiety, recovered less than 5% of its activity after storage for a week at 5 degrees C, but regained over 70% of the lost activity by treatment with 600 microM Ade. 6-Amino-9-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-9H-purine (dFAdo) was a product of the reactivation reaction. Proteolysis of inhibited enzyme identified a modified fragment that spanned residues 82-107 which could not be sequenced past Gly-96. dFDAP-inhibited enzyme and enzyme reacted with normal substrates (i.e. dThd and dAdo) were hydrolyzed between Met-97 and Glu-98 by 0.1 M NaOH. These findings and model studies on the base lability of peptides containing glutamyl esters suggested that the gamma-carboxylate of Glu-98 was esterfied during catalysis. The role of Glu-98 was confirmed by changing this residue to alanine. The specific activity of wild-type enzyme was 3 orders of magnitude greater than that of the mutant enzyme. Collectively, chemical modification and mutagenesis studies have identified Glu-98 as the active site nucleophile of nucleoside 2-deoxyribosyltransferase.

Purification and characterization of a rat liver enzyme that hydrolyzes valaciclovir, the L-valyl ester prodrug of acyclovir

Valaciclovir is an oral prodrug of the antiherpetic agent acyclovir. An enzyme that hydrolyzes valaciclovir to acyclovir, valaciclovir hydrolase (VACVase), was purified from rat liver and characterized. VACVase was a basic (pI 9.4) protein associated with mitochondria. It was monomeric and had a molecular mass of 29 kDa. Amino acid sequences of six VACVase peptides, including its NH2 terminus (13 amino acids) and accounting for approximately 20% of its complete sequence, were not found in the SwissProt protein data base. VACVase hydrolyzed other amino acid esters of acyclovir in addition to valaciclovir (kcat/Km = 58 mM-1 s-1), with a preference for the L-alanyl (kcat/Km = 226 mM-1 s-1) and L-methionyl (kcat/Km = 200 mM-1 s-1) esters. It did not hydrolyze other types of esters or numerous di- and tripeptides and aminoacyl-beta-naphthylamides. Hydrolysis of valaciclovir by VACVase was not inhibited by amastatin, antipain, aprotinin, bestatin, chymostatin, E-64, EDTA, ebelactone A, ebelactone B, elastatinal, leupeptin, pepstatin, or phosphoramidon. It was neither inhibited nor activated by Ca2+, Co2+, Mg2+, Mn2+, or Zn2+. Therefore, this enzyme is not a typical esterase or peptidase and, to our knowledge, it has not been described previously. Its physiological function is not known; however, it may play a significant role in the biotransformation of valaciclovir to acyclovir.

Primary structure differences between proteins C1 and C2 of HeLa 40S nuclear ribonucleoprotein particles

Partial acid cleavage, comparative HPLC tryptic peptide mapping and amino acid sequencing of the C1 and C2 proteins of HeLa heterogeneous nuclear ribonucleoprotein (hnRNP) particles demonstrate that proteins C1 and C2 differ in primary structure by the presence of a 13 amino acid insert sequence in C2. This C2 insert sequence occurs after either glycine 106 or serine 107 in C1. The additional 13 amino acids that are present in C2 account for the observed molecular weight difference between the C1 and C2 hnRNP proteins on SDS polyacrylamide gel electrophoresis. Because C1 and C2 appear identical except for the 13 residue insert and because the 3' and 5' untranslated regions of the corresponding mRNAs also appear to be the same (Swanson et al., Mol. Cell. Biol. 7: 1731-1739), it is possible that both polypeptides are produced from a single transcription unit through an alternative splicing mechanism.

Parent Management of Organization, Time Management, and Planning Deficits among Adolescents with ADHD

Organization, Time Management, and Planning (OTP) problems are a key mechanism of academic failure for adolescents with ADHD. Parents may be well positioned to promote remediation of these deficits; yet, almost nothing is known about OTP management behaviors among parents of middle and high school students with ADHD. In a sample of 299 well-diagnosed adolescents with ADHD, a measure of parental OTP management was psychometrically validated. Latent Class Analysis was conducted to detect distinct patterns of parental OTP management and yielded four unique classes: Parental Control (18.7 %), Parent-Teen Collaboration (20.4 %), Homework Assistance (20.4 %), and Uninvolved (40.5 %). Logistic Regression analyses indicated that maladaptive parental OTP strategies were related to higher levels of parent and adolescent psychopathology. Parental OTP management did not relate to current adolescent OTP skills or GPA, indicating that parents did not select OTP management strategies in immediate response to adolescent functioning. Implications for parent-directed intervention are discussed.

Identification of the nucleotide binding site of HIV-1 reverse transcriptase using dTTP as a photoaffinity label

We have utilized UV-induced cross-linking of [methyl-3H]dTTP to identify the nucleotide binding site on heterodimeric HIV-1 reverse transcriptase (RT). RT was derivatized by irradiating a solution containing [methyl-3H]dTTP and purified recombinant RT for 10 min. The UV-induced cross-linking reaction between dTTP and RT is linear with time of UV exposure up to 10 min, and it has been determined previously that dTTP cross-linking is half-maximal at 90 microM [Cheng, N., Painter, G. R., & Furmann, P.A. (1991) Biochem. Biophys. Res. Commun. 174, 785-789]. Under these reaction conditions, only the 66-kDa subunit of the 66-kDa/51-kDa RT heterodimer was labeled with dTTP. The [methyl-3H]dTTP-labeled RT was fragmented with trypsin and endoproteinase Asp-N, and peptides were purified on reversed phase HPLC. The peptide covalently linked to [methyl-3H]dTTP was subjected to amino acid sequence analysis. The sequencing data localized the nucleotide binding site of RT to Lys-73 in the vicinity of several mutation sites linked to antiviral drug resistance. Since most effective anti-AIDS compounds are inhibitors of RT, information about its dNTP binding site may make it possible to understand the basis for the antiviral activity of nucleoside analogs such as AZT, ddI, and ddC. This information may also be useful for a more rationally based design of anti-HIV agents.

Functional Outcomes of Young Adults with Childhood ADHD: A Latent Profile Analysis

Adults with childhood attention-deficit hyperactivity disorder (ADHD) experience impairment in core functional domains (e.g., educational attainment, occupational status, social relationships, substance abuse, and criminal behavior), but it is currently unclear which impairments co-occur and whether subgroups experience differentiable patterns, none, or all aforementioned functional domains. Latent profile analysis (LPA) was used to characterize patterns of impairment. Data from the Pittsburgh ADHD Longitudinal Study were used. The 317 participants were 25 years old and had childhood ADHD. LPA characterized the variability across substance use (alcohol consumption, cigarette smoking, marijuana use), criminal behavior, peer impairment, educational attainment, maternal relationship, financial dependence, and sexual activity among young adults with childhood ADHD. Childhood predictors of profiles were examined, and ADHD profiles were compared to a matched comparison group without ADHD also followed longitudinally (n = 217). Five profiles were found: prototypic impairment group (54%), high binge-drinking group (17%), high marijuana use group (10%), high criminal activity group (3%), and high cross-domain impairment group (17%). All profiles were impaired compared to non-ADHD young adults. Childhood variables rarely significantly predicted profiles. Young adults with childhood ADHD have differentiable impairment patterns that vary based on substance use, criminal behavior, and number of clinically impaired domains. Nearly all young adult ADHD profiles were impaired in peer, educational, and financial domains, and there was not a nonimpaired ADHD profile. Use of specific substances was elevated among subgroups of, but not all, young adults with ADHD histories. Finally, the high cross-domain impairment profile was impaired in all domains.

Amino acid sequence of UP1, an hnRNP-derived single-stranded nucleic acid binding protein from calf thymus

The UP1 single-stranded nucleic acid binding protein from calf thymus (Herrick, G. & Alberts, B.M. (1976) J. Biol. Chem. 251, 2124-2132) has recently been shown to be a proteolytic fragment derived from the A1 heterogeneous nuclear ribonucleoprotein (hnRNP) (Pandolfo et al. (1985) Nucleic Acids Res. 13, 6577-6590). The NH2-terminus of the 22,162 dalton UP1 protein appears to be blocked, which suggests that UP1 represents the NH2-terminal two thirds of this 32,000 dalton hnRNP protein. The complete amino acid sequence for UP1 was derived from automated sequencing of peptides that were purified by HPLC from digests with trypsin, chymotrypsin, Staphylococcus aureus protease, endoproteinase Lys-C, and cyanogen bromide. Trichloroacetic acid precipitation followed by enzymatic digestion in 2 M urea proved to be the best approach for generating UP1 peptides. By carboxymethylating after, rather than before, digestion it was possible to avoid problems associated with the insolubility of the carboxymethylated UP1. All of the resulting peptides in amounts varying from 2 to 15 nmol were coupled to aminopolystyrene prior to solid-phase sequencing. Using these methods, no difficulties were encountered in assigning glutamic acid residues or in completely sequencing peptides that contained up to 25-30 residues. The relative ease with which the UP1 protein was sequenced, requiring only about a year to complete, and the comparatively modest amount of protein required, less than 5 mg, attests to the usefulness of water soluble carbodiimide coupling and solid-phase sequencing for determining the primary structures of proteins. In addition to serving as a basis for determining structural relationships among various mammalian single-stranded nucleic acid binding proteins, the amino acid sequence of UP1 reveals that the A1 hnRNP protein contains a region of internal sequence homology that apparently corresponds to two independent nucleic acid binding sites.

Improving homework performance among children with ADHD: A randomized clinical trial

OBJECTIVE

Evidence indicates that children with Attention Deficit Hyperactivity Disorder (ADHD) experience acute and prolonged academic impairment and underachievement including marked difficulty with completing homework. This study is the first to examine the effects of behavioral, psychostimulant, and combined treatments on homework problems, which have been shown to predict academic performance longitudinally.

METHOD

Children with ADHD (ages 5-12, N = 75, 71% male, 83% Hispanic/Latino) and their families were randomly assigned to either behavioral treatment (homework-focused parent training and a daily report card; BPT + DRC) or a waitlist control group. Children also participated in a concurrent psychostimulant crossover trial conducted in a summer treatment program. Children's objective homework completion and accuracy were measured as well as parent-reported child homework behaviors and parenting skills.

RESULTS

BPT + DRC had large effects on objective measures of homework completion and accuracy (Cohen's ds from 1.40 to 2.21, ps < .001). Other findings, including unimodal medication and incremental combined treatment benefits, were not significant.

CONCLUSIONS

Behavioral treatment focused on homework problems results in clear benefits for children's homework completion and accuracy (the difference between passing and failing, on average), whereas long-acting stimulant medication resulted in limited and largely nonsignificant acute effects on homework performance. (PsycINFO Database Record

Identification of a 7B2-derived tridecapeptide from bovine adrenal medulla chromaffin vesicles

1. A novel tridecapeptide was isolated from extracts of bovine adrenal medulla chromaffin vesicles and the primary structure determined to be SVPHFSDEDKDPE. 2. This peptide is identical to the C termini of human and porcine 7B2 and is highly homologous to the same region of the mouse and Xenopus lavis protein. 3. In all these species the homologous peptide is preceded by a pair of lysine residues, a potential proteolytic processing site. 4. Ser6 is part of a well-conserved casein kinase II consensus phosphorylation sequence. Evidence for phosphorylation of this residue was obtained during Edman sequencing. 5. Thus, this novel adrenal medullary probably arises from the posttranslational processing of the bovine 7B2 protein.

An evaluation of the effect of methylphenidate on working memory, time perception, and choice impulsivity in children with ADHD

Individuals with Attention-Deficit Hyperactivity Disorder (ADHD) consistently exhibit a stronger preference for immediate rewards than for larger rewards available following a delay on tasks measuring choice impulsivity (CI). Despite this, however, there remains a dearth of studies examining the impact of stimulant treatment on CI as well as associated higher order (e.g., working memory [WM]) and perceptual (e.g., time perception) cognitive processes. The present study examines the effect of osmotic release oral system methylphenidate (OROS-MPH) on CI, WM and time perception processes as well as the relation among these processes before and after taking a regimen of OROS-MPH. Thirty-five children (aged 7-12 years) with a diagnosis of ADHD participating in a concurrent stimulant medication study were recruited to complete computerized assessments of CI, WM, and time perception. Children completed the assessments after administration of a placebo as well as their lowest effective dose of OROS-MPH following a 2-week titration period. The results from one-sample t-tests indicated that OROS-MPH improves both CI and WM in youth with ADHD but does not impact time perception. Further, results revealed no significant association among the various indices of cognitive performance while taking placebo or OROS-MPH. Overall, the findings suggest that while OROS-MPH improves both CI and WM in youth with ADHD, improvements in CI as a result of OROS-MPH are unlikely to be associated with the improvements in WM given the lack of association among the two. Future studies should consider alternate cognitive, emotional, and motivational mechanisms that may account for the impact of OROS-MPH on CI. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The Effects of Stimulant Medication and Training on Sports Competence Among Children With ADHD

The current study examined the relative efficacy of behavioral sports training, medication, and their combination in improving sports competence among youth with attention deficit/hyperactivity disorder (ADHD). Participants were 73 youth (74% male; 81% Hispanic) between the ages of 5 and 12 diagnosed with Diagnostic and Statistical Manual of Mental Disorders (4th ed.) ADHD enrolled in a Summer Treatment Program (STP). The study consisted of a 2 (medication: methylphenidate, placebo) × 2 (sports training: instruction and practice, recreational play) between-groups design and was conducted over a 3-week period during the STP. Sports training was conducted with a novel sport, badminton, to limit previous sport knowledge and to differentiate it from concurrent sports training that occurred within the STP. Objective and subjective measures of sports skills, knowledge, and behavior were collected. Results indicated that, relative to recreational play, brief sports training improved observed and counselor-rated measures of sports competence including sports skills, knowledge, game awareness, effort, frustration, and enjoyment. During sports training, medication incrementally improved children's observed rule following behavior and counselor-rated sportsmanship relative to placebo. In the absence of sports training, medication improved behavior, effort, and sport knowledge. Training in sports skills and rules produced the largest magnitude effects on sports-related outcomes. Therefore, skills training, rather than medication alone, should be used in conjunction with behavioral intervention to teach sports to youth with ADHD. It is recommended that medication be used only as an adjunct to highly structured sports skills training for youth who display high rates of negative behavior during sports activities.

Lifetime caregiver strain among mothers of adolescents and young adults with attention-deficit/hyperactivity disorder

The lifetime maternal caregiver strain (CS) associated with raising a child with attention-deficit/hyperactivity disorder (ADHD) into adolescence and young adulthood was examined in the Pittsburgh ADHD Longitudinal Study (PALS), a longitudinal study of individuals diagnosed with ADHD in childhood and recontacted in adolescence and young adulthood for yearly follow-up. Mothers of adolescents/young adults with (n = 364, 89.6% male; M_age = 19.79) and without childhood ADHD (n = 240, 88.8% male; M_age = 18.97) rated their lifetime maternal CS at Wave 3. Adolescent/young adult (AYA) ADHD and ODD severity measured at Wave 1, AYA delinquency measured at Wave 2, and school disciplinary actions combined from Waves 1 and 2 were explored as mediators of the association between childhood ADHD and lifetime maternal CS at Wave 3 using path analysis. AYA gender and age, parental marital status, maternal depression and ADHD, and highest parental education were included as covariates. Greater lifetime CS was reported among mothers of adolescents/young adults with versus without childhood ADHD. In the mediation model, direct effects of childhood ADHD on AYA ADHD and ODD severity, delinquency, and school discipline problems emerged, and direct effects of AYA ODD severity, delinquency, and school discipline problems on lifetime CS emerged. AYA ODD, delinquency, and school discipline mediated the association between childhood ADHD and lifetime maternal CS. These findings extend research on childhood ADHD to identify AYA sequelae contributing to maternal CS. Future research on the transaction between AYA functional impairment and maternal CS across the transition from adolescence into adulthood is needed to clarify opportunities for intervention. (PsycInfo Database Record (c) 2020 APA, all rights reserved).