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Biomedical subjects

A E Jackson

Publications and source records attributed to A E Jackson.

At least 19 recordsLinked to original sources
PubMed2003

Face recognition in children with a pervasive developmental disorder not otherwise specified.

This study investigates the accuracy and speed of face recognition in children with a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS; DSM-IV, American Psychiatric Association [APA], 1994). The study includes a clinical group of 26 nonretarded 7- to 10-year-old children with PDDNOS and a control group of 65 normally developing children of the same age. Two computerized reaction time tasks were administered: a face recognition task and a control task designed to measure the recognition of abstract visuospatial patterns. The latter were either easy or difficult to distinguish from a set of alternative patterns. The normally developing children recognized the faces much faster than the hardly distinguishable abstract patterns. The children in the PDDNOS group needed an amount of time to recognize the faces that almost equalled the time they needed to recognize the abstract patterns that were difficult to distinguish. The results suggest that, when processing faces, children with PDDNOS use a strategy that is more attention-demanding and, hence, less automatic or "Gestalt-like" than the one used by the control children. The results are discussed in the light of a theory that explains the development of coherent mental representations.

Attention↗
PubMed2000

Evidence that single nucleotide polymorphism in the uncoupling protein 3 (UCP3) gene influences fat distribution in women of European and Asian origin.

AIMS/HYPOTHESIS: Uncoupling proteins are mitochondrial transmembrane carriers implicated in the regulation of energy balance. Dysfunction of UCP3 (the predominant uncoupling protein in skeletal muscle) might therefore be expected to reduce thermogenic capacity, alter energy homeostasis and influence predisposition to obesity and Type II (non-insulin-dependent) diabetes mellitus. A variant in the putative promoter region of UCP3 (-55 c-->t) has recently been identified, and an association with obesity reported in French subjects. Our aim was to study the pathophysiological role of this variant in diabetes-related and obesity-related traits using two distinct ethnic populations. METHODS: The -55 c-->t variant was genotyped in 85 South Indian and 150 European parent-offspring trios ascertained through Type II diabetic probands and in 455 South Indian subjects initially recruited to an urban survey into the prevalence of diabetes. RESULTS: In South Indian and European parent-offspring trios there was no preferential transmission of either allele at the -55 c-->t polymorphism to diabetic offspring (South Indians, p = 0.60; Europeans, p = 0.15). When family members were analysed for intermediate traits, the t-allele was associated with increased waist-to-hip ratio but only in females (South Indian mothers p = 0.036, daughters p = 0.032: European mothers p = 0.037, daughters p = 0.14). These findings were replicated in South Indian females from the population-based survey (p = 0.039). CONCLUSION/INTERPRETATION: The consistent association between the t-allele at this locus and increased waist-to-hip ratio in women from three separate data sets indicates that variation at this polymorphism (or another locus with which it is in linkage disequilibrium) influences fat distribution but that this effect is restricted to females.

Adipose Tissue↗
PubMed1999

Social-cognitive abilities in children with lesser variants of autism: skill deficits or failure to apply skills?

The present study re-examined the ability of children with lesser variants of autism (classified as PDD-NOS) to infer emotions of other people and to describe others in terms of inner, psychological characteristics. It also explores the hypothesis that these children may have the skill to infer mental states of other people, but fail to use these skills spontaneously. Children with lesser variants of autism and normal control children matched for age, sex and intelligence were given three structured emotional role-taking tasks and asked to give two spontaneous descriptions of peers. The results showed that both groups did not differ with respect to their ability to infer other people's emotions in the structured role-taking tasks. In contrast, significant differences were found on the free person descriptions: the children with PDD-NOS used fewer inner, psychological characteristics to describe peers.

Autistic Disorder↗
PubMed1996

Suppression of testicular function using two dose rates of a reversible water soluble gonadotrophin releasing hormone (GnRH) vaccine in colts.

OBJECTIVE: To investigate the effect of two dose rates (200 and 400 ng) of a gonadotrophin releasing hormone (GnRH) vaccine on testicular function. DESIGN: A vaccination dose rate experiment. PROCEDURE: Two injections were administered 4 weeks apart to six colts in each treatment group. To maintain immunosuppression until the end of the breeding season, a third injection was given if antibody titres fell below 1000. RESULTS: Effective antibody titres were present for 12 to 27 weeks. Testosterone concentrations decreased from 2.22 to 0.31 nmol/L 6 weeks after primary vaccination. Androstenedione concentrations decreased from 1.78 to 0.28 nmol/L 5 weeks after vaccination. Testosterone and androstenedione concentrations above 0.69 and 0.87 nmol/L were attained 31 to 43 weeks after vaccination. Mean scrotal widths and lengths decreased over 29 weeks from 9.2 cm and 9.7 cm to 6.7 cm and 7.6 cm. At surgical castration these dimensions were 10.1 cm and 11.0 cm. Mean semen characteristics before vaccination and after recovery were: gel-free volume 16.5 and 13.5 mL, sperm concentration 295.5 x 10(6) and 315.6 x 10(6)/mL, total sperm per ejaculate 4041 x 10(6) and 4657 x 10(6) and live normal spermatozoa 32% and 60%. Histologically, the testes showed active spermatogenesis. The mean testicular parenchyma weights for the 200 and 400 mg groups were 129.0 g and 109.8 g. Daily sperm production per testis and per gram of testis for the 200 and 400 mg groups were 3.7 x 10(8) and 2.8 x 10(6), and 2.3 x 10(8) and 2.0 x 10(6). CONCLUSIONS: Both dose rates suppressed testicular function. Data showed that the vaccine effects were reversible. Individual immune response was less varied in the 200 mg group. Further work is necessary to achieve a less variable response in the immunosuppression of testicular function.

Androstenedione↗
PubMed1995

An exploration of person perception abilities in children with a pervasive developmental disorder not otherwise specified.

This explorative study investigates differences in person perception abilities between a group of children diagnosed as having a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) and a group of normal children of the same age and sex. Person perception, a social-cognitive skill, concerns the way in which children conceptualise other people, their intentions, attitudes, traits and emotions (central), as well as their overt behaviour and their physical characteristics (peripheral). Person perception was investigated by means of a free-person description, in which the child was asked to describe another person. Children with a PDDNOS used more peripheral and less central statements than the control group to describe another person. However, these differences seemed to reflect differences in intelligence between the two groups, rather than differences in a specific social-cognitive skill. The results need to be replicated, but seem to be in line with other studies that suggest that there may be subgroups of the autistic spectrum that show severe social impairment but have good social-cognitive abilities.

Child↗
PubMed1995

Emotional role-taking abilities of children with a pervasive developmental disorder not otherwise specified.

Seven to 12-year-old children with a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) were compared with normal, healthy children of the same age and sex on three different emotional role-taking tasks. In these tasks, children had to use person-specific information to make an inference about another child's emotional reaction and behaviour, Significant differences were found between the PDDNOS group and control group: PDDNOS children performed worse on all three role-taking tasks. However, the differences on one of these tasks could be completely explained by intelligence differences between the two groups. On the other tasks, differences could not or be partially explained by intelligence differences. The results of this study led to the formulation of a more specific hypothesis, namely that PDDNOS children might have problems interpreting social information when affectively charged background information has to be used.

Aptitude↗
PubMed1994

Assessing vulvar lesions. Laser-Doppler flowmetry as a possible technique.

Over the last decade, laser-Doppler flowmetry has been used to measure perfusion in the skin. To date it has not been used on the lower genital tract, and we describe preliminary results of measurements taken on the vulva. We include results from a control population and describe two cases with premalignant or malignant changes in the vulva.

Female↗
PubMed1993

Immunocastration of colts and immunospeying of fillies.

A series of experiments using an ovalbumin conjugated gonadotrophin releasing hormone was used to stimulate antibody production, suppress testosterone secretion and depress testicular function in yearling and 2 year old colts and fillies. In the preliminary experiment, an injectable oil-based formulation was administered to yearling colts. Testicular development and testosterone secretion were retarded for a period of approximately 28-32 weeks while antibody titres were greater than 1:1000. An implant and water-soluble vaccine (200 and 400 mg) is presently being tested in 2 year old colts. Testicular dimensions and testosterone concentrations decreased following vaccination. Preliminary results indicate that the effects of the implant are reversible and last for approximately 30 weeks. The water-soluble vaccine produced effective antibodies for 10-19 weeks. Plasma testosterone of all colts was reduced to gelding levels (0.2 ng/mL) while antibody titres were greater than 1:1000. Semen evaluation, morphometric analysis and daily sperm production data indicate that the testes recovered normal function. These experiments are continuing and more definitive data on the vaccine and its reversibility will be available at their conclusion. Ovarian activity of the treated fillies (200 and 400 mg) ceased soon after vaccination. Their progesterone concentrations have remained below 1 ng/mL for 20 weeks. The untreated control fillies have continued to cycle normally as determined by ovarian ultrasonography and progesterone concentrations.

Animals↗
PubMed1993

Adverse effects on sperm movement characteristics in women with minimal and mild endometriosis.

OBJECTIVE: To test the effect of peritoneal fluid from infertile women with minimal or mild endometriosis on sperm movement characteristics in comparison with fertile and infertile women with no endometriosis. DESIGN: A prospective observer-blind trial. SETTING: Academic infertility department. SUBJECTS: 57 women undergoing diagnostic laparoscopy or laparoscopic sterilisation. MAIN OUTCOME MEASURES: Changes in sperm movement characteristics in semen samples provided during routine infertility investigation or from sperm donors. Computer assisted semen analysis (CASA) performed using a Celltrack-S system. RESULTS: Significant reductions in linearity (P < 0.05), amplitude of lateral head displacement (P < 0.01), straight line velocity (P < 0.01), and curvilinear velocity (P < 0.01) (but not percentage motility) were observed. CONCLUSIONS: Peritoneal fluid from women with minimal or mild endometriosis adversely effects sperm movement characteristics in comparison to fertile women.

Adult↗
PubMed1992

Exposure to LHRH agonists in early pregnancy following the commencement of mid-luteal buserelin for IVF stimulation.

Exposure to buserelin in early pregnancy has been reported following its use in in-vitro fertilization treatment cycles. The number of reported cases is small. There are still no answers regarding embryotoxicity, and the need for luteal support is still unclear. A further six cases are reported here, five receiving luteal support and resulting in the delivery of healthy children, and one, without luteal support ending in a first trimester miscarriage. We propose that further data should be collected to allow adequate monitoring and follow-up of these pregnancies.

Abortion, Spontaneous↗
PubMed1991

A preliminary study of immunological castration in colts.

This study tested the effectiveness of a conjugated GnRH vaccine for stimulating antibody production, suppressing testosterone secretion and depressing testicular development in yearling colts. Two colts were allocated to each of three groups, (1) control, (2) subcutaneous and (3) intramuscular vaccinations. Two injections of the vaccine were given 11 weeks apart. Liveweight gain was not affected by vaccination but plasma testosterone concentrations in the treated colts were suppressed and their antibody titres to GnRH were greater than 1:1000. Testicular development in the treated colts also was retarded at this time, which was approximately 28 weeks after the first injection. Semen samples, containing spermatozoa, were collected from all the colts prior to their castration at the end of the investigation. Antibody titres and testosterone concentrations in the treated colts had returned to levels similar to those of the controls by the end of the experiment. The testes of the vaccinated colts were still smaller than those of the controls on castration but were, nevertheless, increasing in size. Morphometric analysis of testicular histology and daily sperm production data indicated that the testes of the treated colts were recovering and would probably have regained normal function had they been left in situ.

Animals↗
PubMed1990

Use of a selectable reporter for the isolation of mammalian regulatory genes.

A general method is described for isolating the genes encoding differentiation-specific activators of transcription using genetic selection. Employing regulation of the prolactin encoding gene (PRL) as a model, we have shown that the hamster dihydrofolate reductase-encoding gene (dhfr) is an effective dominant selectable reporter in this methodology. The dhfr coding region was ligated to the rat PRL promoter, and the resultant construct was stably transfected into DHFR- Chinese hamster ovary (CHO) cells, where it had little or no activity. Transfection of these cells with plasmid DNA, containing the coding region of a pituitary-specific transcription factor (Pit-1/GHF-1) in a eukaryotic expression vector, resulted in transfectants in which activation of the chimeric construct, pPRLdhfr, had occurred, enabling these cells to be selected on the basis of their DHFR+ phenotype. Our results suggest that this strategy could be used to isolate unknown genes that regulate a variety of differentiated functions.

Animals↗
PubMed1990

Epidermal growth factor and phorbol ester regulate prolactin gene expression via distinct pathways.

Previous studies, involving phosphorylation of cytoplasmic proteins and localization of DNA regulatory elements, have suggested that epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) have similar actions on prolactin (PRL) gene expression by pituitary (GH) cells. However, little is presently known about whether the actions of these two factors involve common gene-distal intermediates. In the present study, we have employed two approaches to examine this question. Chronic exposure of GH3 cells to TPA, which strongly down-regulates protein kinase C activity, completely inhibited acute TPA stimulation of transient expression of a transfected PRL promoter construct ((-187)PRL-CAT), but did not inhibit EGF stimulation of either accumulation of endogenous PRL mRNA or of expression of (-187)PRL-CAT. Furthermore, the acute stimulatory effects of EGF and TPA on expression of (-187)PRL-CAT were additive. Each of these observations implies that EGF and TPA have gene-distal actions on PRL gene expression that are at least partially non-overlapping.

Animals↗
PubMed1989

Ultrastructural immunoperoxidase investigations of human glomerular cells in tissue culture.

In order to elucidate the cells produced from human glomerular cultures, a pre-embedding ultrastructural immunoperoxidase technique was developed to investigate the precise localisation of a panel of monoclonal antibodies specific to human glomerular antigens in situ and used to identify the same antigens in vitro. The results obtained were correlated with the morphological features of the cells demonstrated by scanning electron microscopy. The study was able to show the presence of epithelial and mesangial cells in tissue culture, to confirm previous results indicating that glomerular endothelial cells are not present and to give some insight into the production of different basement membrane components by different cell types.

Antibodies, Monoclonal↗
PubMed1989

Proximal rat prolactin promoter sequences direct optimal, pituitary cell-specific transcription.

Previous studies have shown that transferred hybrid constructs containing the PRL promoter are expressed specifically in rat pituitary (GH) cell lines. However, it is not yet clear which DNA region(s) is primarily responsible for expression directed by this promoter in pituitary cells. In the present studies we have examined the DNA sequences required for cell type-specific transcription of the rat PRL (rPRL) promoter either during transient expression in intact cells or in nuclear chromatin extracts. RNase protection and nuclear run-on transcription assays showed directly that a PRL-chloramphenicol acetyltransferase (CAT) construct containing about two kilobase-pairs of the rPRL promoter region (pPRL-CAT) is transcribed specifically in pituitary (GH3) cells. Analysis by transient expression in GH3 cells of pPRL-CAT and its 5' deletions showed that 1) deletion of sequences between positions -1957 and -958 did not significantly affect CAT activity; 2) the first 187 basepairs (bp) of the rPRL promoter directs full CAT activity; and 3) 98% of this activity is accounted for by rPRL DNA sequences between positions -187 and -113, containing two GH3 chromatin footprinting sites. Analysis in GH3 cell nuclear extracts showed that transcription of PRL-CAT constructs is unaffected by successive 5' deletions from position -1957 to -187, and that further deletion to -75 yielded only a moderate (approximately 2-fold) decrease in transcription.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effects of interaction with calcineurin on the reactivities of calmodulin lysines.

Calmodulin was trace labeled by acetylation with [3H]acetic anhydride in the presence and absence of a 30% molar excess of the phosphatase calcineurin; phenylalanine was included in the reaction mixtures as an internal standard. The level of 3H acetylation of each of the 7 lysines was determined and corrected for differences arising from reaction conditions using the labeling of the internal standard, following procedures that are closely similar to those used in a previous study of the interaction of calmodulin with myosin light chain kinase (Jackson, A. E., Carraway, K. L., III, Puett, D., and Brew, K. (1986) J. Biol. Chem. 261, 12226-12232). The interaction with calcineurin was found to produce a 10-fold reduction in the acetylation of lysine 75, with lesser but significant effects on lysines 21 and 148. A small but reproducible perturbation of lysine 77 was also observed. The results are similar to those that are produced by the interaction with myosin light chain kinase. However, when they are compared with two recent reports between which there are major discrepancies (Manalan, A. S., and Klee, C. B. (1987) Biochemistry 26, 1382-1390; Winkler, M. A., Fried, V. A., Merat, D. L., and Cheung, W. Y. (1987) J. Biol. Chem. 262, 15466-15471), our results are in good agreement with those obtained in the former study. From the location of the perturbed groups in the three-dimensional structure of calmodulin, it appears that the interaction site on calmodulin for calcineurin, as well as for myosin light chain kinase, is very extended and may include hydrophobic pockets at homologous sites near the carboxyl-terminal ends of the two halves of the molecule.

Acetic Anhydrides↗