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Biomedical subjects

A Collins

Publications and source records attributed to A Collins.

At least 55 records · Page 3Linked to original sources
PubMed2001

Ecological momentary assessment of temptation and lapse in dieting.

Although some research attention has been given to the factors associated with temptation and lapse in dieting, the majority of research has focused on individuals in weight loss clinical trials and relied heavily on retrospective self-report data. The present study sought to overcome these limitations by using ecological momentary assessment (EMA) techniques to examine situations of dietary temptation, lapse, and minimal dietary consequence with a sample of overweight dieters (N=30) attempting to lose weight on their own. Results support and extend previous research findings on dietary temptation and lapse. In general, results indicate that recent consumptive activity, location, mood state, type of activity, and abstinence violation effects were related to moments of temptation and/or lapse. Education on the factors associated with dietary temptation and lapse and strategies for addressing these factors is imperative for both dieters in formal programs and those attempting to lose or maintain weight on their own.

Journal Article↗
PubMed2001

The impact of frozen embryos on emotional reactions during in vitro fertilization.

BACKGROUND: Emotional reactions of couples were investigated during in vitro fertilization (IVF) at a private clinic in Sweden. The purpose was to compare such reactions between couples who obtained supernumerary embryos that could be cryopreserved and couples without such embryos. METHODS: Forty women and men undergoing IVF treatment monitored individually their emotional reactions daily for one complete treatment cycle from the first day of down-regulation until the outcome of treatment was known. Ratings were extracted and analyzed from two separate days; the very first day of treatment and the day of embryo transfer. RESULTS: The group of women (n=16; 40%) with supernumerary embryos suitable for cryopreservation reported a greater increase in optimism than the group (n=24; 60%) without such embryos (p=0.024). Correspondingly, women with supernumerary embryos reported less pessimism than women without such embryos (p=0.014). Among men there was no difference in optimism or pessimism between the groups. The women and men with supernumerary embryos did not differ in distress reactions compared to those women and men without such embryos. There was no correlation between optimism and distress on the day of embryo transfer in women; r=-0.167 and men; r=-0.135 respectively. CONCLUSION: The presence of frozen embryos increased optimistic and reduced pessimistic feelings about pregnancy among women undergoing IVF treatment. However, the couples' increased optimism on the day of embryo transfer did not seem to reduce their experience of distress.

Adult↗
PubMed2001

Association and linkage of leprosy phenotypes with HLA class II and tumour necrosis factor genes.

Previous analyses indicate major gene control of susceptibility to leprosy per se and the HLA class II region has been implicated in determining susceptibility and control of clinical phenotype. Segregation analysis using data from 76 Brazilian leprosy multi-case pedigrees (1166 individuals) supported a two locus model as the best fit: a recessive major gene and a recessive modifier gene(s) (single locus vs two locus model, P = 0.0007). Combined segregation and linkage analysis to the major locus, showed strong linkage to HLA class II (HLA-DQB1 P = 0.000002, HLA-DQA1 P = 0.000002, HLA-DRB1 P = 0.0000003) and tumour necrosis factor genes (TNF P = 0.00002, LTA P = 0.003). Extended transmission disequilibrium testing, using multiple affected family members, demonstrated that the common allele TNF*1 of the -308 promoter region polymorphism showed linkage and/or association with disease per se, at a high level of significance (P < 0.0001). Two locus transmission disequilibrium testing suggested susceptibility (TNF*1/LTA*2) and protective (TNF*2/LTA*2) haplotypes in the class iii region. Taken together the segregation and HLA analyses suggest the possibility of more than one susceptibility locus in the MHC.

Brazil↗
PubMed2001

Allelic association and disease mapping.

The application of allelic association to map genes for complex traits, particularly using high-density maps of single nucleotide polymorphisms in candidate regions, is an area of very active research. Here we present some aspects of the methodology and applications to both major gene mapping, which illustrates the effectiveness of the method, and oligogenes, where methods are still in flux and for which there have been relatively few successes to date. Several important considerations emerge, including the selection of the optimal metric for measuring association and the importance of modelling the decline in association with distance given the variability in association in a candidate region. The Malecot model of association with distance is shown to have a resolution of greater than 50 kilobases but the available evidence suggests that considerably higher resolution might be achieved with dense single nucleotide polymorphism (SNP) maps.

Alleles↗
PubMed2001

LDB2000: sequence-based integrated maps of the human genome.

MOTIVATION: Integrated maps are useful for gene mapping and establishing the relationship between recombination and sequence. In this paper we describe algorithms and their implementation for constructing sequence-based integrated maps of the human chromosomes, which are presented in LDB2000, a web based resource. Gene mapping efforts are now focussing on linkage disequilibrium mapping and extension of the integrated map to represent the extent of linkage disequilibrium in different genomic regions would further increase the utility of these maps. RESULTS: Sequence-based integrated maps have been completed for chromosomes 21 and 22. These maps provide locations for genes and polymorphic markers in sequence and on genetic linkage, radiation hybrid and cytogenetic scales. Single nucleotide polymorphisms associated with genes in the maps are also included and their sequence locations indicated. Related locus information, such as aliases and expression information, can be searched on the WWW site.

Algorithms↗
PubMed2001

PIRA PCR designer for restriction analysis of single nucleotide polymorphisms.

UNLABELLED: Primer-introduced restriction analysis (PIRA-PCR) is widely used to detect Single Nucleotide Polymorphisms (SNPs). To create artificial Restriction Fragment Length Polymorphism (RFLP), a mismatch is usually introduced near the end of the primer that is close to the mutation of interest. We describe in this report a www-based computer program that screens for the suitable mismatches, designs the primers, lists the appropriate restriction enzymes and other related information. AVAILABILITY: The computer program, with related descriptions, is available at http://cedar.genetics.soton.ac.uk/public_html/primer2.html.

Base Pair Mismatch↗
PubMed2001

A sequence-based integrated map of chromosome 22.

The near-completion of the sequence for chromosome 22q revolutionizes map integration. We describe a sequence-based integrated map containing 968 loci including 516 known or predicted gene sequences, 317 STSs not included in these sequences, and 135 nonexpressed multinucleotide polymorphisms. The published sequence spans 34.6 Mb, inclusive of gaps estimated to total 1.1 Mb, compared with a top-down estimate of 43 Mb. This discrepancy is discussed, but will not be resolved until more of the genome is analyzed. The radiation hybrid map has 5% error in order and 34% error in location exceeding 1 Mb. The utility of a composite location based on evidence other than sequence is limited to regions not yet sequenced. A genetic map conditional on sequence order was constructed from pairwise lods. Its length of 74.8 cM in males and 80.2 cM in females is slightly less than the previous estimate not constrained by sequence order. Five recombination hot spots are detected, with differences in location between the sexes. Male recombination correlates with repetitive DNA, whereas female recombination does not. It remains to be seen whether this is true for other human chromosomes. An algorithm to improve the fit of cytogenetic bands sequence location reduces the discrepancies in cytogenetic assignment from 61 to 38. This sequence-based integrated map is represented in the genetic location database (LDB2000), which is available at http://cedar.genetics.soton.ac.uk/public_html/LDB2000.html.

Base Sequence↗
PubMed2001

Combination of linkage evidence in complex inheritance.

The central problem of complex inheritance is to combine evidence from data that typically differ in markers, phenotypes, ascertainment, and other factors, without sacrificing the reliability that lods have given to linkage mapping for major loci. Here we evaluate 5 possible solutions on 200 replicates simulated in Genetic Analysis Workshop 10. Two methods differ from less efficient ones by distinguishing the tails of a normal distribution. Maximum likelihood scores (currently implemented only for the BETA model) and the approach of Self and Liang perform about as well as pooling samples, which is not feasible with heterogeneous data. With moderately heterogeneous data the Self and Liang method appears to be more efficient than maximum likelihood scores. Although improvements are being made in sample design and statistical analysis, the problem of combining linkage evidence from multiple data sets appears to have been solved. Allelic association presents different problems not yet addressed.

Alleles↗
PubMed2001

A tournament of linkage tests in complex inheritance.

The performance of some weakly parametric linkage tests in common use was compared on 200 replicates of oligogenic inheritance from Genetic Analysis Workshop 10. Each random sample for the quantitative trait was dichotomized at different thresholds and also selected through 2 affected sibs, generating 8 combinations of sample and variable. The variance component program SOLAR performed best with a continuous trait, even in selected samples, when the population mean was used. The sib-pair program SIBPAL2 was best in most other cases when the phenotype product, population mean, and empirical estimates of pair correlations were used. The BETA program that introduced phenotype products was slightly more powerful than maximum likelihood scores under the null hypothesis and approached but did not exceed SIBPAL2 under its optimal conditions. Type I errors generally exceeded expectations from a chi(2) test, but were conservative with respect to bounds on lods. All methods can be improved by use of the population mean, empirical correlations, logistic representation for affection status, and correct lods for samples that favour the null hypothesis. It remains uncertain whether all information can be extracted by weakly parametric methods and whether correction for ascertainment bias demands a strongly parametric model. Performance on a standard set of simulated data is indispensable for recognising optimal methods.

Algorithms↗
PubMed2001

Experimental prostate epithelial morphogenesis in response to stroma and three-dimensional matrigel culture.

To reproduce the structural and functional differentiation of human prostatic acini in vivo, prostatic epithelial and stromal cells derived from human primary cultures were cocultured in Matrigel. In the absence of stroma and serum, epithelial spheroids composed of solid masses of stratified and cuboidal cells formed. Outer cells of the spheroid expressed cytokeratins 1, 5, 10, and 14, whereas the inner cells expressed cytokeratin 18. The addition of 2% serum induced formation of a lumen surrounded by a layer of one or two cuboidal and columnar epithelial cells. The further addition of stromal cultures, dihydrotestosterone, and estrogen induced polarization of the epithelium and increased spheroid-forming efficiency. Epithelium expressed either cytokeratin 18 alone or additionally cytokeratins 1, 5, 14, and 10. All spheroid epithelium expressed prostate-specific antigen and prostate-specific membrane antigen. Androgen receptor was only detected in the presence of stroma, serum, and hormones. Thus, development of a functional and morphologically correct prostate gland in vitro is dependent on extracellular matrix, steroid hormones, and factors from stromal cells and serum.

Animals↗
PubMed2000

Allelic association in the FRAX region.

The sex chromosomes enable direct determination of haplotypes, and the analysis of 8 microsatellite markers from the FRAX region on Xq27-q28 contributes 7219 independent haplotypes from our study in Wessex. Allelic association increases with frequency of alleles, and is less for trinucleotide than dinucleotide repeats. The estimate of epsilon, the exponential decline of association with distance in kb, is 0.0023. The swept radius 1/epsilon estimates the distance at which disequilibrium falls to e(-1) approximately .37 of its initial value. The current study estimates the swept radius of association to be 433 kb, which is surprisingly close to estimates for SNPs, and suggests that a marker density of 1/100 kb should be powerful in regions such as FRAX. An explanation for these results is offered, and some speculations made about what will be found when SNPs are subjected to an equally intensive study in multiple regions.

Alleles↗
PubMed2000

The influence of stress and state anxiety on the outcome of IVF-treatment: psychological and endocrinological assessment of Swedish women entering IVF-treatment.

BACKGROUND: Comparing stress levels in women entering IVF treatment with those of fertile controls as well as relating these levels to the outcome of IVF. METHODS: State anxiety and personality profiles as well as stress hormones were studied in 22 normally menstruating women entering IVF treatment for tubal infertility. Their personality profiles as well as state anxiety scores measured before entering IVF treatment were related to the outcome of treatment. Twenty-two fertile women served as controls. Stress markers were serum prolactin and cortisol. These were estimated by radioimmunoassay. The psychological evaluation included the Karolinska Scales of Personality (KSP) and state anxiety as measured by the STAI questionnaire. Basal FSH on cycle day 3 and E2 and P4 AUC during the luteal phase were evaluated as hormonal predictors for the outcome of IVF treatment. RESULTS: Comparison of the personality profiles of the two groups, showed that infertile women had significantly higher scores of suspicion (p>0.05), guilt (p>0.05), and hostility (p>0.01), but lower somatic anxiety (0.05) and indirect aggression (0.05) than fertile controls. The infertile women also had significantly higher levels of prolactin and cortisol throughout the menstrual cycle. Serum cortisol, prolactin and FSH levels on cycle day 3 did not differ between the women who conceived after IVF treatment and those who did not conceive. However, significant differences were found in E2 and P4 AUC (p>0.01) in the luteal phase between those women who became pregnant and those who failed. There was a trend (p<0.06) toward higher state anxiety levels among the women who did not succeed in becoming pregnant after IVF treatment. CONCLUSIONS: The main findings suggest that infertile women have a different personality profile in terms of more suspicion, guilt and hostility as compared to the fertile controls, perhaps as a response to their infertility. Their stress levels in terms of circulating prolactin and cortisol levels were elevated compared to the fertile controls. Psychological stress may affect the outcome of IVF treatment since state anxiety levels among those who did not achieve pregnancy were slightly higher than among those who became pregnant.

Adult↗
PubMed2000

Combined segregation and linkage analysis of 59 Hodgkin's disease families indicates the role of HLA determinants.

Through a literature search, we identified a total of 59 nuclear families with Hodgkin's disease (HD). The affected individuals in these families were HLA haplotyped. To evaluate the role of HLA-linked determinants of HD and investigate the mode of inheritance of familial HD, a combined segregation and linkage analysis was performed, together with a semi-parametric analysis of sib pairs. Amongst single locus models, a general single locus model showed no improvement over an additive model. However, a two locus additive model gave the best overall fit and a lod score of 3.55. We conclude that HD is most likely to be determined by both an HLA-associated major gene and other non-HLA genetic factors together with environmental effects.

HLA Antigens↗
PubMed2000

Combined segregation and linkage analysis of inflammatory bowel disease in the IBD1 region using severity to characterise Crohn's disease and ulcerative colitis. On behalf of the GISC.

Inflammatory bowel disease (IBD) is a chronic relapsing disorder affecting the gastro-intestinal tract and is subdivided into two main subtypes: Crohn's disease (CD) and ulcerative colitis (UC). Although the aetiology of IBD is unknown, a strong genetic susceptibility is suggested and different candidate regions have been identified for both CD and UC. The IBD1 region on chromosome 16 has been confirmed to be important for susceptibility to CD, whereas conflicting evidence has been obtained for UC. We performed a combined linkage and segregation analysis in the identified IBD1 region on a sample of 82 extended families with IBD using a parametric method implemented in the computer program COMDS. This approach allows simultaneous evaluation of linkage while estimating the mode of inheritance and to include severity of the trait to characterise the CD and UC phenotypes. Our results are consistent with the presence of a major gene in the IBD1 region close to D16S408 involved in both UC and CD. Furthermore, our data support evidence that a single mutation in the gene leads more frequently to UC, whereas inheritance of two mutant alleles results in the more severe CD. In our study the IBD1 locus was found to have a major role in IBD predisposition in the Italian population.

Adult↗
PubMed2000

Psychosocial factors, attitude to menopause and symptoms in Swedish perimenopausal women.

OBJECTIVES: To analyze attitude to menopause from women's own accounts and to examine whether psychosocial factors and attitude are associated with symptom reporting. METHODS: The data form part of a population-based longitudinal study of a cohort of women who have been followed annually for 5 years using psychological interviews and rating scales, health screening and hormonal characterization. The data reported here were collected at the fourth follow-up when the women (n = 148) were 53 years old. RESULTS: Women were classified as perimenopausal (27%), postmenopausal (15%), hormone replacement therapy (HRT) users (52%) and hysterectomized (6%), based on self-reports. More than half the women (51%) had a positive attitude to menopause, 24% had a negative attitude and 25% had a neutral attitude. Menopausal status was not associated with attitude to menopause. Factor analysis of symptom ratings yielded ten independent factors comprising negative mood, vasomotor symptoms, decreased sexual desire, memory problems, sleep-related symptoms, vaginal dryness, urogenital problems, joint pain, vitality and increased sexual desire. Only vasomotor symptoms and joint pain were associated with menopausal status. The other symptoms were more strongly related to psychosocial factors, life-style and attitude to menopause. CONCLUSIONS: The results support the view of the menopause as a developmental phase associated with an increased self-awareness and a stronger personal identity. More than half the women held a positive view of the menopause, whereas the remaining proportion of women had either a negative or a neutral attitude. Only vasomotor symptoms and joint pain were associated with postmenopausal status. Other symptoms were significantly related to psychosocial factors, life-style and attitude to menopause.

Affect↗