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Biomedical subjects

J B Reid

Publications and source records attributed to J B Reid.

At least 19 recordsLinked to original sources
PubMed1999

Gibberellin 2-oxidation and the SLN gene of Pisum sativum.

Two cDNAs encoding gibberellin 2-oxidases were isolated from maturing pea seeds. The first, PsGA2ox1, was isolated by activity screening of a Lambda-ZAP cDNA library excised into phagemid form and expressed in Escherichia coli. The second, PsGA2ox2, was obtained initially as a PCR product using degenerate primers designed according to conserved regions of plant 2-oxoglutarate-dependent dioxygenases. E. coli heterologous expression products of PsGA2ox1 and PsGA2ox2 converted GA1 to GA8, as shown by HPLC-radiocounting, and gas chromatography-MS. PsGA2ox1 converted GA20 to GA29, but GA20 was a poor substrate for the PsGA2ox2 expression product. Furthermore, PsGA2ox1 converted GA29 to GA29-catabolite at a low level of efficiency while PsGA2ox2 did not catalyse this step. A cDNA of PsGA2ox1 isolated from plants of genotype sln contained a single base deletion which was predicted to produce a truncated protein and gibberellin 2-oxidase activity could not be demonstrated from this cDNA. A 10 bp size difference between the introns of the SLN and sln PsGA2ox1 genes was used to show co-segregation between the SLN and sln phenotypes and the size of the PCR products. PsGA2ox1 transcripts were more abundant in cotyledons than in shoots, while the reverse was the case for PsGA2ox2. The expression patterns of the genes, together with the effects of the sln mutation, indicate that PsGA2ox1 plays a major role in GA20 deactivation in both shoots and maturing seeds, while the PsGA2ox2 gene might be important for GA1 deactivation in the shoot.

Amino Acid Sequence↗
PubMed1998

Comparison of two community alternatives to incarceration for chronic juvenile offenders.

The relative effectiveness of group care (GC) and multidimensional treatment foster care (MTFC) was compared in terms of their impact on criminal offending, incarceration rates, and program completion outcomes for 79 male adolescents who had histories of chronic and serious juvenile delinquency. Results show that boys who participated in MTFC had significantly fewer criminal referrals and returned to live with relatives more often. Multiple regression analyses showed that assignment to a treatment condition (i.e., GC or MTFC) predicted official and self-reported criminality in follow-up beyond other well-known predictors of chronic juvenile offending (i.e., age at 1st offense, number of previous offenses, age at referral).

Adolescent↗
PubMed1998

Environmental and genetic variance in children's observed and reported maladaptive behavior.

The genetic and environmental contributions to children's maladaptive behavior are assessed in a sample of 154 twin pairs (77 MZ twin pairs and 77 DZ twin pairs), who range in age from 6 to 11 years. To bridge the strengths of behavioral genetic methods and environmental assessment techniques, we use a multimethod, multimeasure approach to data collection, and analyze the data using behavioral genetic modeling techniques. Results indicate that genetic variation accounts for a majority of the variance in parent-reported child maladaptive behavior (average = 62%). One parent-report measure also suggests a smaller, significant contribution of shared environmental variance. In contrast to the parental ratings, the observational coding and global impressions of parent-twin interactive behavior suggest that shared environment is the primary source of variance accounting for parent and child maladaptive behavior. This is due, in part, to the direct influence one's interactive partner has on the expression of maladaptive behavior in an interactive setting. When controlling for the co-participant's behavior, genetic variation increases and shared environmental variation decreases.

Child↗
PubMed1997

Observational assessments of the interaction of implant recipients with family and peers: preliminary findings.

Two experiments were conducted to determine the feasibility of direct observational methods in the assessment of social interactions between cochlear implant recipients and their families and peers. With laboratory analogs of parent-child interactions and peer interactions, children with implants and deaf children were videotaped. These videotapes were then coded for specific patterns of behavior. The results established the feasibility of direct observational assessments of deaf children and implant recipients and identified behavioral foci that could serve as effective indexes of implant outcome. The study also suggested that the peer entry paradigm may not be suitable for deaf children under the age of 7 years.

Age Factors↗
PubMed1997

The LS locus of pea encodes the gibberellin biosynthesis enzyme ent-kaurene synthase A.

Gibberellins (GAs) are hormones required for several aspects of plant development, including internode elongation and seed development in pea (Pisum sativum L.). The first committed step in the GA biosynthesis pathway is the conversion of geranylgeranyl diphosphate (GGDP) to ent-kaurene via copalyl diphosphate (CDP). These two reactions are catalyzed by the cyclases ent-kaurene synthase A (KSA) and ent-kaurene synthase B (KSB), respectively. Previous genetic and biochemical analysis of the GA-responsive ls-1 mutant of pea suggested that GA levels are reduced in a developmental- and organ-specific manner due to reduced GA biosynthesis. Analysis of cellfree enzyme preparations from WT and ls-1 embryos at contact point reveals that ls-1 reduces the activity of KSA but not KSB. To characterize the ls-1 mutation in more detail, a cDNA coding for a pea KSA was cloned and shown to be encoded by the LS locus. The ls-1 mutation results from an intronic G to A substitution that causes impaired RNA splicing. To determine the activity of the KSAs encoded by the LS and ls-1 alleles, a new in vitro assay for combined KSA and KSB activity has been developed using the KSB gene of pumpkin. Using recombinant WT KSA and KSB fusion proteins, GGDP is converted to ent-kaurene in vitro. Based on the sequence of RT-PCR products, three different truncated KSA proteins are predicted to exist in ls-1 plants. The most abundant mutant KSA protein does not possess detectable activity in vitro. Nevertheless, the ls-1 allele is not null and is able to encode at least a partially functional KSA since a more severe is allele has been identified. The ls-1 mutation has played a key role in identifying a role for GAs in pea seed development in the first few days after fertilization, but not in older seeds. KSA expression in seeds is developmentally regulated and parallels overall GA biosynthesis, suggesting that KSA expression may play an important role in the regulation of GA biosynthesis and seed development.

Alkyl and Aryl Transferases↗
PubMed1997

Mendel's stem length gene (Le) encodes a gibberellin 3 beta-hydroxylase.

We describe the isolation of the Le gene of pea, which controls internode elongation and originally was described by Mendel. Heterologous screening of a pea cDNA library yielded a partial clone that was 61% identical to coding regions of the putative Arabidopsis gibberellin 3 beta-hydroxylase gene, GA4. DNA gel blot analysis with this cDNA revealed a HindIII restriction fragment length polymorphism between pea isolines differing at Mendel's Le locus. Genomic clones of the GA4-related gene were isolated from the Le and le isolines. Polymerase chain reaction combined with restriction fragment length polymorphism analysis were used to show that the gene mapped to the Le locus. A cDNA containing a complete open reading frame of the pea GA4-related gene was amplified by polymerase chain reaction from each isoline. Recombinant expression in Escherichia coli demonstrated that the product of the Le cDNA was a gibberellin 3 beta-hydroxylase that is able to convert GA20 to the bioactive GA1. Substantially reduced levels of gibberellin 3 beta-hydroxylase activity were measured, after expression of the le cDNA, by using identical methods. This reduced activity was associated with an alanine-to-threonine substitution in the predicted amino acid sequence of the enzyme near its proposed active site.

Amino Acid Sequence↗
PubMed1994

Toxicity and carcinogenicity of riddelliine following 13 weeks of treatment to rats and mice.

Toxicity studies of riddelliine, a member of a class of pyrrolizidine alkaloids, were conducted because riddelliine has been found to contaminate human food sources. Groups of male and female Fischer rats were administered riddelliine by gavage in phosphate buffer at doses up to 10 mg/kg, and B6C3F1 mice at doses up to 25 mg/kg, five times a week. The animals were necropsied after 13 weeks of treatment or after a 7 or 14 week recovery period. Body weight gains were inversely related to dose in both rats and mice. Body weight of the 1.0 and 3.3 mg/kg female rats and 10.0 and 25.0 mg/kg mice remained depressed during the 14 week recovery period. At 13 weeks, significant findings included dose-related hepatopathy and intravascular macrophage accumulation in rats and hepatocytomegaly in mice. During the 14 week recovery period these lesions persisted and hepatic foci of cellular alteration in male rats and bile duct proliferation in female rats and male and female mice increased in severity. In the 10 mg/kg group of female rats adenomas of the liver occurred in two of ten at 13 weeks and in one of five at the 14 week recovery period. In separate studies, the frequency of micronucleated erythrocytes in peripheral blood was increased in male mice administered a single dose (150 mg/kg) of riddelliine. Increases in unscheduled DNA and S-phase syntheses were detected in primary hepatocytes from rats and mice treated with riddelliine at doses up to 25.0 mg/kg for 5 or 30 days. In mating trials in rats and mice, pup weights from treated dams at birth and during suckling were lower than controls. Thus, riddelliine is genotoxic and carcinogenic and may cross the placenta and/or be found in milk, causing developmental toxicity in rodents.

Adenoma, Liver Cell↗
PubMed1991

A comparative evaluation of parent-training interventions for families of chronic delinquents.

Fifty-five families of chronically offending delinquents were randomly assigned to parent-training treatment or to service traditionally provided by the juvenile court and community. The families in the parent-training group received an average of 44.8 hours of professional contact (23.3 hours of which were phone contacts), and each control group family received treatment estimated at more than 50 hours on the average. Comparisons of police contact data at baseline and subsequent years for the two groups showed that subjects in both groups demonstrated reduced rates of offending during the followup years. The finding most relevant was significant treatment-by-time effect for offense rates, with most of this effect accounted for by a greater reduction in serious crimes for the experimental group during the treatment year, and a similar reduction of the community control group occurring in the first of three followup years. These early decrements in offense rates persisted during followup for both groups. Throughout the study, boys in the experimental group spent significantly less time in institutional settings than did boys in the control group. Parent training had a significant impact, but the reduction in offending was produced at very high emotional cost to staff. Although it is clear that this population requires substantial treatment resources, this study underscores the need for more work on prevention.

Adolescent↗
PubMed1991

Mediational screening as a model for prevention research.

Examined here is Pillow, Sandler, Braver, Wolchik, and Gersten's (this issue) strategy for screening prevention trial participants. The reviewer concludes that their selection strategy should increase the statistical power of prevention outcome studies, increase intervention cost effectiveness, and help to prevent their possible iatrogenic effects. Also, their model points up inadequacies in the longitudinal data on which most prevention strategies are based, and their model could well serve as a template for future research.

Child↗
PubMed1987

Abusive parents' perceptions of child problem behaviors: an example of parental bias.

The behavior of children in 21 child abusive and 21 nonabusive matched comparison families were compared using home observations performed by professional independent observers and parental report measures (Becker Bipolar Adjective Checklist, Child Behavior Checklist, Parent Daily Report). Parental report measures of child conduct problems differed significantly between the two groups, independent observations showed few significant differences in rates of either child or parental behaviors. Results are discussed in terms of the validity of parental perceptions and reports of child problem behaviors, the informativeness of differing reports for diagnosis and clinical treatment, and the need to gather corroboration across various sources and settings before clinical decisions are made that may irrevocably alter a child's future development.

Child↗
PubMed1986

Influence of housing conditions for mice on the results of a dermal oncogenicity bioassay.

Male C3H/HeJ mice were thrice weekly given 25 microliter applications of 0.25, 0.05, or 0.01% (w/w) benzo(a)pyrene (BaP) in acetone, or acetone alone, to clipped dorsal skin from 12 to 14 weeks of age for the remainder of their life spans. There were two groups of 40 mice for each treatment regimen, one group being housed in conventional stainless-steel wire mesh cages and the other in polycarbonate cages with wood shavings held in an enclosed ventilated cabinet. Under both housing conditions, tumor incidence was directly related and latency inversely related to BaP concentration. The time-adjusted incidence of epidermal neoplasms was significantly greater for the groups housed in polycarbonate cages. Mortality rates were directly related to BaP concentration and were significantly enhanced by the polycarbonate-cage housing conditions for the high and intermediate concentrations. Survival patterns for the two acetone control groups were similar. These findings indicate that differences in housing conditions can influence both the incidence and the latency of local neoplasms produced in response to the chronic application of a carcinogen in dermal oncogenesis bioassays.

Animals↗
PubMed1983

Family interactions of assaultive adolescents, stealers, and nondelinquents.

Eleven adolescent chronic offenders apprehended for assaultive crimes in the community were observed in their family homes. This group was matched with 11 adolescents apprehended for stealing and with 11 adolescents with no court contact. Assaultive adolescents, unlike their controls, ranked significantly higher among their own family members in terms of their total aversive behavior in the family home. The results support the notion that assaultive adolescents are more involved with fighting with their siblings in the family home and consequently have had more practice in fighting than their controls, thereby preparing them for assaultive behavior in the community. Assaultive adolescents had more female siblings than male siblings, whereas nondelinquent adolescents had more male than female siblings.

Adolescent↗
PubMed1981

The consistency of a class of coercive child behaviors across school settings for individual subjects.

This study addressed the problem of the intraindividual consistency of a class of coercive child behaviors across two school settings. Observational data collected on eight coercive behaviors of 53 boys in classrooms and on the playground. Previous Guttman scale analyses had shown that these eight coercive behaviors constituted a response class. The rates of the eight coercive responses in the response class were rank-ordered separately for each of the 53 subjects in each of the two settings. The intraindividual rank-order correlations were all positive, and 37 were statistically reliable. This number of significant correlations was further shown to be significantly greater than chance. It was concluded that there is a substantial amount of cross-situational consistency if intraresponse class analyses are done for individuals.

Aggression↗