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L A Jones

Publications and source records attributed to L A Jones.

At least 19 recordsLinked to original sources
PubMed2006

Pre-irradiation and post-irradiation fading of the Harshaw 8841 TLD in different environmental conditions.

The pre-irradiation and post-irradiation fading of a commercially available LiF:Mg,Cu,P thermoluminescent detector (TLD)-the Harshaw 8841 TLD-have been assessed. The Harshaw 8841 TLD comprises three TLD-700H chips (99.7% 7LiF and 0.03% 6LiF by weight) and one TLD-600H chip (4.4% 7LiF and 95.6% 6LiF by weight). Pre-irradiation and post-irradiation fading were measured for storage times up to 164 d and three different storage temperatures (-8, 25 and 50 degrees C). Dosemeters were irradiated in a mixed photon-neutron field so that the fading behaviour of the photon and neutron signals could be studied. The TLD-700H and TLD-600H chips exhibited complex changes in sensitivity and signal that depended on storage time, storage temperature and the type of radiation to which the chips had been exposed. However, the magnitudes of these changes in sensitivity and signal were relatively small. TLD-600H and TLD-700H, therefore, exhibit good stability of sensitivity and signal.

Artifacts↗
PubMed2006

When do auditory/visual differences in duration judgements occur?

Four experiments examined judgements of the duration of auditory and visual stimuli. Two used a bisection method, and two used verbal estimation. Auditory/visual differences were found when durations of auditory and visual stimuli were explicitly compared and when durations from both modalities were mixed in partition bisection. Differences in verbal estimation were also found both when people received a single modality and when they received both. In all cases, the auditory stimuli appeared longer than the visual stimuli, and the effect was greater at longer stimulus durations, consistent with a "pacemaker speed" interpretation of the effect. Results suggested that Penney, Gibbon, and Meck's (2000) "memory mixing" account of auditory/visual differences in duration judgements, while correct in some circumstances, was incomplete, and that in some cases people were basing their judgements on some preexisting temporal standard.

Acoustic Stimulation↗
PubMed2006

Ocular toxoplasmosis: in the storm of the eye.

Ocular toxoplasmosis (OT) can occur in the children of mothers infected with Toxoplasma gondii during pregnancy. It is not limited to the congenitally infected, but can also occur following adult-acquired infection or as a result of disease reactivation in immune-compromised and pregnant individuals. Many aspects of immune privilege in the eye, including constitutive TGF-beta expression and reduced MHC class 1 expression, would appear at first to favour parasite survival. Conversely, many of the mechanisms that control parasite multiplication in other anatomical sites, such as nitric oxide expression, IFN-gamma and TNF-alpha, are known to disrupt immune privilege and are associated with ocular damage. Taking into account the opposing needs of limiting parasite multiplication and minimizing tissue destruction we review the pathogenesis of OT in the murine model.

Animals↗
PubMed2005

Genome wide significant linkage in schizophrenia conditioning on occurrence of depressive episodes.

BACKGROUND: Schizophrenia shows substantial clinical heterogeneity. One common important clinical variable in presentation is the occurrence of episodes of major depression. METHODS: We undertook analyses in an attempt to detect loci that influence susceptibility to, or modify the clinical expression of, schizophrenia according to the occurrence of episodes of major depression. We used a logistic regression framework in which lifetime presence/absence of major depression was entered as a covariate in the linkage analysis of our UK schizophrenia affected sibling pair series (168 affected sibling pairs typed for a 10 cM map of microsatellite markers). RESULTS: Inclusion of presence/absence of depression as a covariate detected a genome wide significant linkage signal on chromosome 4q28.3 at 130.7 cM (LOD = 4.59; p = 0.038; increase in maximum LOD over univariate analysis (ILOD) = 3.62). Inclusion of the depression covariate also showed suggestive evidence of linkage on 20q11.21 (LOD = 4.10; expected to occur by chance 0.093 times per genome scan, ILOD = 2.83). CONCLUSIONS: Our findings identify loci that may harbour genes that play a role in susceptibility to, or modify the risk of, episodes of major depression in people with schizophrenia.

Analysis of Variance↗
PubMed2005

Cervical cancer among Vietnamese women: efforts to define the problem among Houston's population.

INTRODUCTION: Asian American/Pacific Islanders (AAPIs) in the United States (US) continue to bear a disproportionate burden of cancer. This report focuses on the interviews with local health-care delivery providers, directors, administrators, and community outreach liaisons in the Vietnamese community in Houston, Texas. METHODS: The Center for Minority Health (CMRH) at the University of Texas M.D. Cancer Center interviewed 17 leaders, as defined above, to identify factors that have a negative impact on screening practices among Vietnamese women. RESULTS: The results show that some of the barriers to cervical cancer screening include: lack of knowledge, lack of female physicians, language barriers, lack of insurance, and embarrassment. Interviews established that "prevention" is a Western concept that the Vietnamese community has not yet adopted. Vietnamese women used their churches, community physicians (licensed or not), circle of friends, and families for their health information. Many patients used herbs as alternative or complementary therapies. CONCLUSION: Cultural factors play a vital role in limiting Vietnamese women in the use of cervical screening. Further research needs to focus on identifying specific barriers and how they can be overcome.

Female↗
PubMed2003

Self-reported schizotypy and bipolar disorder: demonstration of a lack of specificity of the Kings Schizotypy Questionnaire.

Previous studies have demonstrated that schizophrenia patients score highly on self-reported measures of schizotypy such as the Kings Schizotypy Questionnaire (KSQ), but relatively little is known about the specificity of these self-reported features to schizophrenia. We aimed to explore the specificity of schizotypal features to schizophrenia by measuring their prevalence in subjects with bipolar disorder. The Kings Schizotypy Questionnaire (KSQ) was administered to participants (n=92) in a sibling-pair genetic linkage study of bipolar disorder. Scores were compared with those of participants in a similarly designed, concurrent family study of schizophrenia (n=135) and psychiatrically well controls (n=263). The bipolar group had significantly more schizotypal features than controls but significantly less than schizophrenia patients. Whether a bipolar subject had experienced positive psychosis had no effect on his/her schizotypy score. We conclude that elevated self-reported schizotypy as measured by the KSQ is not specific to schizophrenia, and may be associated with functional psychosis in general.

Adult↗
PubMed2003

A systematic genomewide linkage study in 353 sib pairs with schizophrenia.

We undertook a genomewide linkage study in a total of 353 affected sib pairs (ASPs) with schizophrenia. Our sample consisted of 179 ASPs from the United Kingdom, 134 from Sweden, and 40 from the United States. We typed 372 microsatellite markers at approximately 10-cM intervals. Our strongest finding was a LOD score of 3.87 on chromosome 10q25.3-q26.3, with positive results being contributed by all three samples and a LOD-1 interval of 15 cM. This finding achieved genomewide significance (P<.05), on the basis of simulation studies. We also found two regions, 17p11.2-q25.1 (maximum LOD score [MLS] = 3.35) and 22q11 (MLS = 2.29), in which the evidence for linkage was highly suggestive. Linkage to all of these regions has been supported by other studies. Moreover, we found strong evidence for linkage (genomewide P<.02) to 17p11.2-q25.1 in a single pedigree with schizophrenia. In our view, the evidence is now sufficiently compelling to undertake detailed mapping studies of these three regions.

Genetic Linkage↗
PubMed2001

A genomewide linkage study of age at onset in schizophrenia.

There is strong evidence for a genetic contribution to age at onset of schizophrenia, which probably involves both susceptibility loci for schizophrenia and modifying loci acting independent of disease risk. We sought evidence of linkage to loci that influence age at onset of schizophrenia in a sample of 94 affected sibling pairs with DSM-IV schizophrenia or schizoaffective disorder, and age at first psychiatric contact of 45 years or less. Individuals were genotyped for 229 microsatellite markers spaced at approximately 20 cM intervals throughout the genome. Loci contributing to age at onset were sought by a quantitative maximum-likelihood multipoint linkage analysis using MAPMAKER/SIBS. A nonparametric multipoint analysis was also performed. The genomewide significance of linkage results was assessed by simulation studies. There were six maximum-likelihood LOD score peaks of 1.5 or greater, the highest being on chromosome 17q (LOD = 2.54; genomewide P = 0.27). This fulfils Lander and Kruglyak's [1995: Nat Genet 11:241-247] criteria for suggestive linkage in that it would be expected to occur once or less (0.3 times) per genome scan. However, this finding should be treated with caution because the LOD score appeared to be almost solely accounted for by the pattern of ibd sharing at one marker (D17S787), with virtually no evidence of linkage over flanking markers. None of the linkage results achieved genomewide statistical significance, but the LOD score peak on chromosome 13q (LOD = 1.68) coincided with the region showing maximum evidence for linkage in the study by Blouin et al. [1998: Nat Genet 20:70-73] of categorical schizophrenia.

Age of Onset↗
PubMed2001

Sustained and selective attention as measures of genetic liability to schizophrenia.

We tested for a relationship between attention and genetic liability to schizophrenia. Samples of probands with DSM-IV schizophrenia (n=20), their well first-degree relatives (n=40) and healthy controls (n=82) were tested using measures of sustained attention (degraded-stimulus continuous performance test: DS-CPT) and selective attention (spatial negative priming task). Assuming a liability-threshold model, we predicted that probands would display greater attentional decrements than controls and that the relatives would show intermediate levels of decrement. We did not observe the predicted pattern of effect using either measure, although the probands showed a trend towards less negative priming. However, our results may have been affected by self-selection bias in probands and relatives and clinical heterogeneity among probands, which could have reduced our power to detect effects.

Adolescent↗
PubMed2001

Effect of administration route on FES uptake into MCF-7 tumors.

We have observed that intraperitoneal administration of [(18)F]fluoroestradiol (FES), a radiolabeled estrogen receptor ligand, results in higher abdominal organ uptake and slower blood clearance than intravenous administration in female mice. In SCID mice bearing MCF-7 human tumors SC, IP administration resulted in tumor uptake that was only about one third that obtained with IV administration. Thus, the route of administration of a radiopharmaceutical for imaging or radiotherapy of a tumor in the abdomen, an ovarian tumor, for example, could have a profound effect on the efficiency and selectivity of delivery of the agent to the tumor.

Animals↗
PubMed2001

Comparison of animal models for the evaluation of radiolabeled androgens.

Biodistribution of two 18F-labeled androgens and an 124I/125I-labeled androgen were studied in five androgen receptor (prostate) animal models with or lacking sex hormone binding globulin (SHBG). As models for androgen-receptor positive ovarian cancer, xenografts of three human ovarian cancer cell lines were tested in SCID mice. SHBG in the prostate model systems significantly affects the metabolism, clearance, and distribution of the radiolabeled androgens in several tissues, but ovarian cancer animal models were disappointing.

Androgens↗
PubMed2001

The contact lens and myopia progression (CLAMP) study: design and baseline data.

BACKGROUND: Although previous contact lens myopia control studies indicate that rigid contact lenses slow the progression of myopia in children, they have all suffered from limitations that challenge the significance of their results. The Contact Lens and Myopia Progression (CLAMP) Study addresses the limitations of previous studies and attempts to correct them by implementing alternative Study designs. The CLAMP study also measures all the ocular components to examine the potential mechanism of treatment effect. METHODS: Eligible children were fitted with rigid gas-permeable contact lenses and enrolled in a run-in period to determine whether they were able to adapt to rigid contact lens wear. Subjects who successfully completed the run-in period were randomly assigned to wear rigid contact lenses or soft contact lenses for the remainder of the 3-year study. The primary outcome measure will be the 3-year change in cycloplegic autorefraction; the secondary outcome measures will include the 3-year change in axial length, peripheral autorefraction, crystalline lens curvatures, corneal curvature and thickness, accommodation, and intraocular pressure, which are being measured annually. RESULTS: We examined 148 eligible subjects who participated in the run-in period. Of the 148 eligible subjects, 116 (78.4%) were able to adapt to rigid contact lens wear and were enrolled in the CLAMP Study. The mean age of the participants at the baseline visit was 10.5 years, and 59.5% were girls. At the randomization visit, the mean (+/-SD) spherical equivalent refractive error in the right eye was -2.09 +/- 0.89 D, the mean central curvature of the right cornea by videokeratography was 44.5 +/- 1.3 D, and the mean axial length of the right eye was 24.13 +/- 0.71 mm. CONCLUSIONS: Four of five children aged 8- to 11-years-old were able to adapt to rigid gas-permeable contact lens wear. The CLAMP Study aims to further clarify the effect of rigid gas-permeable contact lenses on myopia progression in children.

Astigmatism↗
PubMed2001

Vaccinia virus vectors with an inactivated gamma interferon receptor homolog gene (B8R) are attenuated In vivo without a concomitant reduction in immunogenicity.

The vaccinia virus (VV) B8R gene encodes a secreted protein with homology to the gamma interferon (IFN-gamma) receptor. In vitro, the B8R protein binds to and neutralizes the antiviral activity of several species of IFN-gamma, including human and rat IFN-gamma; it does not, however, bind significantly to murine IFN-gamma. Here we report on the construction and characterization of recombinant VVs (rVVs) lacking the B8R gene. While the deletion of this gene had no effect on virus replication in vitro, rVVs lacking the B8R gene were attenuated for mice. There was a significant decrease in weight loss and mortality in normal mice, and nude mice survived significantly longer than did controls inoculated with parental virus. This is a surprising result considering the minimal binding of the B8R protein to murine IFN-gamma and its failure to block the antiviral activity of this cytokine in vitro. Such reduction in virulence could not be determined in rats, since they are considerably more resistant to VV infection than are mice. Finally, deletion of the B8R gene had no detectable effects on humoral immune responses. Mice and rats vaccinated with the rVVs showed identical humoral responses to both homologous and heterologous genes expressed by VV. This study demonstrates that the deletion of the VV B8R gene leads to enhanced safety without a concomitant reduction in immunogenicity.

Animals↗
PubMed2001

Aggressive behaviour in patients with schizophrenia is associated with catechol-O-methyltransferase genotype.

BACKGROUND: Evidence exists for an association between aggression and schizophrenia. Although the aetiology of aggression is multifactorial, three studies have reported associations between polymorphisms of the catechol-O-methyltransferase (COMT) gene and aggression in schizophrenia. AIMS: To replicate these findings in a larger sample using the Overt Aggression Scale (OAS). METHOD: A sample of 180 people with DSM-IV schizophrenia were rated for aggression using the OAS. Kruskal-Wallis and contingency table analyses were applied to the OAS results. RESULTS: The high-activity homozygotes showed significantly higher scores of aggression, whereas the heterozygotes showed significantly lower scores. The odds ratio for aggression for the high-activity homozygotes was 2.07 (95% Cl=1.03-4.15), whereas that for the heterozygotes was 0.54 (95% Cl=0.30-1.00). CONCLUSIONS; The high-activity COMT homozygote confers a higher risk of recorded aggression in schizophrenia. Heterozygotes had a significantly lower risk, which may represent an example of heterosis/heterozygote advantage.

Aggression↗
PubMed2001

Correlation of p53 mutations with resistance to platinum-based chemotherapy and shortened survival in ovarian cancer.

PURPOSE: The p53 tumor suppressor gene plays a central role in cell cycle regulation and induction of apoptosis. We analyzed p53 alterations and their impact on response to chemotherapy and clinical outcome in ovarian cancer patients. EXPERIMENTAL DESIGN: One hundred seventy-eight ovarian carcinomas, snap frozen and stored at -80 degrees C, were analyzed for mutations of the p53 gene (exons 2-11) by single-strand conformation polymorphism and DNA sequencing and for p53 overexpression by immunohistochemistry (monoclonal antibody DO7). RESULTS: p53 mutations were found in 56% (99 of 178) of the tumors, and 62% of these were located in evolutionary highly conserved domains of the gene. Time to progression and overall survival were significantly shortened in patients with p53 mutations compared with wild-type p53 (P = 0.029 and P = 0.014) and patients with mutations in highly conserved domains as opposed to nonconserved domains or wild-type p53 (P = 0.010 and P = 0.007). p53 protein overexpression (>10% positively stained nuclei) was found in 62% (110 of 178). Time to progression and overall survival were shorter in cases with p53 overexpression (cutpoint, 10%: P = 0.071 and P = 0.056) but only marginally significant. Resistance to adjuvant cisplatin or carboplatin chemotherapy was significantly more frequent in patients with p53 overexpression (P = 0.001) or p53 missense mutations (P = 0.008) than patients with normal p53. CONCLUSIONS: p53 alterations correlate significantly with resistance to platinum-based chemotherapy, early relapse, and shortened overall survival in ovarian cancer patients in univariate analysis. In multivariable analysis though, p53 was not an independent prognostic factor.

Aged↗