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Biomedical subjects

T Bryan

Publications and source records attributed to T Bryan.

34 records · Page 2Linked to original sources
PubMed1987

Human retroviral sequences on the Y chromosome.

Novel endogenous human retroviral sequences were cloned by low-stringency hybridization, using the pol gene of endogenous human retrovirus 51-1. One clone, lambda NP-2, contained gag, pol, env, and long terminal repeat sequences related to the corresponding portions of clone 51-1 and the closely related full-length endogenous human retrovirus 4-1. The sequence of the env gene of NP-2 was 73% homologous to that of 4-1. Genomic Southern blots of male and female DNAs showed that NP-2 is located on the Y chromosome and that the Y chromosome also contains one other sequence closely related to the env and 3' flanking regions of NP-2. Conservation of flanking DNA suggests that the second Y chromosome copy of the NP-2 env sequence arose by gene duplication rather than provirus insertion.

Base Sequence↗
PubMed1986

Amplification and chromosomal dispersion of human endogenous retroviral sequences.

Endogenous retroviral sequences in humans have undergone amplification events involving both viral and flanking cellular sequences. We cloned members of an amplified family of full-length endogenous retroviral sequences. Genomic blotting, employing a flanking cellular DNA probe derived from a member of this family, revealed a similar array of reactive bands in both humans and chimpanzees, indicating that an amplification event involving retroviral and associated cellular DNA sequences occurred before the evolutionary separation of these two primates. Southern analyses of restricted somatic cell hybrid DNA preparations suggested that endogenous retroviral segments are widely dispersed in the human genome and that amplification and dispersion events may be linked.

Animals↗
PubMed1984

Distinctive termini characterize two families of human endogenous retroviral sequences.

Human DNA contains many copies of endogenous retroviral sequences. Characterization of molecular clones of these structures reveals the existence of two related families. One family consists of full-length (8.8 kilobases) proviral structures, with typical long terminal repeates (LTR's). The other family consists of structures, which contain only 4.1 kilobases of gag-pol sequences, bounded by a tandem array of imperfect repeats 72 to 76 base pairs in length. Typical LTR sequences that exist as solitary elements in the genome were cloned and characterized.

Base Sequence↗
PubMed1984

Conversational interactions between mothers and learning-disabled or nondisabled children during a problem-solving task.

This study focused on mother-child interactions during a problem-solving task to determine whether (a) mothers of learning-disabled children engage in conversational buffering to facilitate their child's participation in the task, and (b) whether learning-disabled children differ from nondisabled children in their use of language with their mothers. The results of this study provide some evidence that mothers of both learning-disabled and nondisabled children engage in conversational buffering, although there were few differences between the mothers of the learning-disabled and nondisabled children. Differences between learning-disabled and nondisabled children showed that the learning-disabled were more likely to agree with and less likely to disagree with their mothers than were the nondisabled children. These findings provide some evidence of maternal conversational buffering and suggest that learning-disabled children's previously reported unassertive conversational style in peer interactions extends to talk with their mothers.

Child↗
PubMed1983

Learning disabled boys' performance and self-assessments on physical fitness tests.

30 learning disabled boys drawn from a segregated private school for learning disabled children and 22 from a public school mainstream program and 22 nondisabled boys performed two physical fitness tests, sit-ups and shuttle run in one of two conditions. While normal achievers performed significantly better on one of the tests, there were no differences between the two samples of learning disabled youngsters. However, students' comparisons of their performance with classmates' indicated that learning disabled youngsters in the private school ranked themselves more favorably than those in mainstream classrooms.

Adolescent↗
PubMed1982

Learning disabled children's syntactic proficiency on a communicative task.

Previous studies have generally examined learning disabled children's syntactic ability either on structured tasks or by analyzing oral language samples collected under conditions not typical of natural communicative settings. Thus, these studies are of limited value in exploring the impact of learning disabled children's deficits in linguistic structure on their use of language in social contexts. The purpose of this study was to investigate learning disabled children's syntactic proficiency during a task requiring them to convey information to a listener. Subjects were selected on the bases of teacher ratings, reading achievement scores, and Peabody Picture Vocabulary Test IQ scores within the normal range; those children identified as learning disabled received low ratings and demonstrated underachievement (below 40th percentile for their grade) in reading. Oral language samples were collected by having learning disabled and normally achieving children in grades two, four, six, and eight participate in a referential communication task in which they described abstract shapes to an experimenter. The length and syntactic complexity of the children's descriptions were assessed. Learning disabled children in all grades were found to produce shorter mean t-units and shorter mean main clauses than nondisabled children even on this relatively simple communicative task. Although learning disabled children's linguistic problems have previously been characterized as subtle, these findings suggest that their productive language deficits may be significant enough to interfere with even the informal and elliptical conversations characteristic of communication among peers and family members.

Adolescent↗
PubMed1981

Identification and cloning of endogenous retroviral sequences present in human DNA.

Using nonstringent annealing conditions and a 2.75-kilobase segment of cloned African green monkey DNA that specifically hybridizes to the proviruses of AKR ecotropic murine leukemia virus (MuLV) and baboon endogenous virus (BaEV) as a probe, we detected related sequences in three different preparations of human brain DNA fragments. The blot-hybridization pattern obtained with cleaved human DNA was similar to that previously reported for the interaction of MuLV cDNA and cleaved mouse DNA and suggested the presence of numerous copies of retrovirus-related sequences in the human genome. The labeled 2.75-kilobase fragment derived from cloned monkey DNA was used to screen a human DNA library in Charon 4A. One clone obtained hybridized to three contiguous MuLV-and BaEV-reactive fragments of the cloned monkey DNA and to multiple fragments of human DNA including a prominent 1.0-kilobase EcoRI fragment also present in the clone.

Animals↗
PubMed1981

Detection and cloning of murine leukemia virus-related sequences from African green monkey liver DNA.

By using low-stringency nucleic acid hybridization conditions and specific subgenomic segments of the AKR ecotropic provirus as probes, murine leukemia virus (MuLV)-related sequences were detected in African green monkey (AGM) liver DNA. The MuLV-reactive segments present in restricted AGM DNA ranged from 1.9 kilobases (kb) to greater than 10 kb in size. On the basis of this finding, a 17-kb segment was cloned from a partial EcoRI AGM library in lambda Charon 4A which shared nearly 5 kb of homology with AKR ecotropic MuLV DNA. The MuLV-related sequences detected in restricted preparations of AGM DNA or present in the cloned monkey DNA reacted with probes mapping 2.0 to 7.0 kb from the 5' terminus of the AKR ecotropic provirus. The AGM clone also contained repeated sequences that flanked the MuLV-related segment. Labeled, subgenomic, MuLV-reactive segments of the monkey clone hybridized to multiple restriction fragments of AGM liver DNA, indicating the presence of several copies of the MuLV-related sequences.

Animals↗
PubMed1980

Identification of ecotropic proviral sequences in inbred mouse strains with a cloned subgenomic DNA fragment.

A specific probe for detecting ecotropic murine leukemia virus sequences was constructed by cloning a 500-base-pair DNA segment, corresponding to a portion of the env region of the AKR ecotropic virus, in a pBR322/Escherichia coli K-12 host/vector system. This probe was used to screen the cellular DNAs of six inbred strains of mice for the presence of ecotropic retroviral DNA sequences by the Southern blot hybridization procedure. Three copies of ecotropic viral DNA were detected in AKR/N (a high-ecotropic virus strain) and two were found in BALB/c (a low-ecotropic virus strain) DNAs. As expected, no sequences reactive with this probe were found in NFS mouse DNA (a virus-negative strain). However, cellular DNA sequences that reacted strongly with the ecotropic-specific DNA probe were detected in certain NZB, C57L, and 129 mice (all virus-negative strains). In contrast to the reactive sequences in AKR and BALB/c, the reactions were chiefly associated with EcoRI segments that were subgenomic in size.

Animals↗
PubMed1968

Productive infection of Bacillus subtilis 168, with bacteriophage SP-10, dependent upon inducing treatments.

Strains of Bacillus that harbor defective phage PBSX were found to be insensitive to SP-10(C), although the phage adsorbed to these insensitive strains. Strains that did not carry the phage were sensitive to SP-10(C). B. subtilis 168 ind(-), which can be tranduced by SP-10(C) but is nonpermissive for the phage, was rendered phage-sensitive after treatment with ultraviolet (UV) light or mitomycin C. After induction with UV light, maximal sensitivity to SP-10(C) was obtained at a multiplicity of infection (MOI) of approximately 14; with mitomycin C induction, an MOI of approximately 1.0 was required. Phage maturation in sensitized cells was followed by plating infected streptomycin-sensitive cells in the presence of streptomycin at various stages during phase development. The latent period was estimated at 60 to 75 min. We suggest that the resistance of B. subtilis 168 to SP-10 is controlled, at least in part, by the presence of a defective prophage.

Bacillus subtilis↗
PubMedDate not supplied

Conformity to peer pressure by students with learning disabilities: a replication.

This study assessed the reported responses of junior high school students with learning disabilities and normally achieving classmates to peer pressure to conform in prosocial and antisocial activities. The results replicate those of an earlier study in finding that students with learning disabilities indicated more willingness than their classmates to conform to peer pressure to engage in antisocial actions.

Achievement↗
PubMedDate not supplied

The influence of affect on the achievement and behavior of students with learning disabilities.

Research indicates that students with learning disabilities are likely to be at greater risk for experiencing negative affect than their higher achieving counterparts. The purpose of this article is to review recent research on the effects of affect on thoughts, cognition, and behavior. This research finds that induced positive affects leads to more accurate performance on math, greater learning of new vocabulary, and better performance on a new learning task. Implications of and suggestions for follow-up studies of negative and positive affect in students with learning disabilities are presented.

Adolescent↗
PubMedDate not supplied

The influence of affect on social-information processing.

This study examined the impact of four affect induction conditions (self-induced positive affect, music-induced positive affect, music-induced negative affect, and neutral affect) on the social-information-processing skills of 96 seventh-grade students with and without learning disabilities using the Dodge (1983) model of social skills. Following a 1-minute affect induction, students were presented with a social problem and asked a series of questions that tested their social skills. Although the results did not find significant differences between school-identified students with and without learning disabilities, there were significant main effects for language skills and affect induction. Students above the median on the Iowa Test of Basic Skills language test generated more solutions and fewer negative responses than students below the median. Students in the self-induced positive affect condition generated more solutions, whereas students in the music-induced positive affect condition generated more embellishments and perceived less interpretation (negative/positive), than students in the neutral and negative affect conditions. The implications of these results for research and practice are discussed.

Adolescent↗
PubMedDate not supplied

The effects of occupational therapy with sensory integration emphasis on preschool-age children with autism.

OBJECTIVE: Using single-subject research design, the effects of an occupational therapy intervention emphasizing sensory integration with five preschool children with autism were examined. METHOD: In the AB design, nonengagement, mastery play, and interaction were measured, using videotape clips of each child's free play in the preschool. Following a 3-week baseline, an occupational therapist provided one-on-one sessions and consultation to teachers for 10 weeks. RESULTS: When baseline and intervention phases were compared, four children demonstrated decreased frequency of nonengaged behavior, and three demonstrated increased frequency of mastery (goal-directed) play. Improvements in frequency of interaction were minimal. CONCLUSION: The results support descriptions in the literature regarding the behavioral changes that children with autism can make when participating in intervention using a sensory integration approach.

Attention↗