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S Dempsey

Publications and source records attributed to S Dempsey.

14 recordsLinked to original sources
PubMed2002

Association of early life factors and acute lymphoblastic leukaemia in childhood: historical cohort study.

In a historical cohort study of all singleton live births in Northern Ireland from 1971-86 (n=434,933) associations between early life factors and childhood acute lymphoblastic leukaemia were investigated. Multivariable analyses showed a positive association between high paternal age (> or =35 years) and acute lymphoblastic leukaemia (relative risk=1.49; 95% confidence interval (CI)=0.96--2.31) but no association with maternal age. High birth weight (> or =3500 g) was positively associated with acute lymphoblastic leukaemia (relative risk=1.66; 95% CI=1.18--2.33). Children of mothers with a previous miscarriage or increased gestation (> or =40 weeks) had reduced risks of ALL (respective relative risks=0.49; 95% CI=0.29--0.80, and 0.67; 95% CI=0.48--0.94). Children born into more crowded households (> or =1 person per room) had substantially lower risks than children born into less crowded homes with also some evidence of a lower risk for children born into homes with three adults (relative risks=0.56; 95% CI=0.35-0.91 and 0.58; 95% CI=0.21-1.61 respectively). These findings indicate that several early life factors, including living conditions in childhood and maternal miscarriage history, influence risk of acute lymphoblastic leukaemia in childhood.

Abortion, Spontaneous↗
PubMed2002

Inactivation of the Fas gene by Alu insertion: retrotransposition in an intron causing splicing variation and autoimmune lymphoproliferative syndrome.

Mutations in the Fas (apo-1, CD95) gene result in autoimmune lymphoproliferative syndrome (ALPS). These mutations are dominated by small deletions and point mutations that result in splicing errors or missense changes. We report here a novel mutation caused by retrotransposon insertion, which results in loss of exon 8 and ALPS. A father and son suffering from recurrent lymphadenopathy were examined for resistance to Fas-mediated apoptosis. A functional defect was detected and RT-PCR analysis revealed two different copies of Fas mRNA, one normal and a second shorter version lacking exon 8. DNA analysis of the genomic region between exons seven and nine in the longer copy revealed two PCR products, one being 331 base pairs (bp) longer than expected. Sequencing revealed that intron 7 had undergone an insertion event with an Alu element (99.31% homology with Alu-Sb1) of 331 bp. This element included a 34-bp Poly A tract that was flanked on each side by a perfect 17 bp direct duplication of the target site. Both patients were heterozygous for the mutated allele that produced Fas mRNA lacking exon 8, although not due to loss of a splice junction. The structure of the insertion suggests that the Alu element may have integrated by retrotransposition, and represents the first report of a retrotransposon causing ALPS.

Alu Elements↗
PubMed2001

Using PAC nested deletions to order contigs and microsatellite markers at the high repetitive sequence containing Npr3 gene locus.

Highly polymorphic di- and tetranucleotide repeats in and around Npr3, a potential candidate gene for hypertension, have been identified using a novel approach. Because this chromosomal site is rich in repetitive DNA and difficult to sequence, P1 artificial chromosomes were retrofitted with a loxP transposon to map the gene sequence within a clone using a series of nested deletions. Sequences from ends of deletions 1-3 kb apart identified a (CA)(20) and a (TA)(18)-(CA)(8) repeat 8 kb upstream and within an intron of Npr3, respectively. DNA from 17 individuals was analyzed for length polymorphisms in these and eight additional repeats identified in 200 kb of working draft sequence from this region in GenBank. The sequence contigs and microsatellite repeats from GenBank were ordered using the P1-derived artificial chromosome deletion series. Several of these repeats were found to vary considerably in length in the set of genomic DNA tested. Since this site in chromosome 5p has recently been implicated in disease in studies with genetically hypertensive rats, the microsatellite markers reported here will be useful for genetic analysis and may even be implicated in the disease process in humans. We discuss how these types of data are useful for interpreting draft DNA sequence coming out of the genome projects, and the utility of deletion clones as a resource for ordering contigs and gap filling.

Alleles↗
PubMed1998

Chronic L-arginine treatment increases cardiac cyclic guanosine 5'-monophosphate in rats with aortic stenosis: effects on left ventricular mass and beta-adrenergic contractile reserve.

OBJECTIVES: We tested the hypothesis that nitric oxide (NO) cyclic guanosine 5'-monophosphate (GMP) signaling is deficient in pressure overload hypertrophy due to ascending aortic stenosis, and that long-term L-arginine treatment will increase cardiac cyclic GMP production and modify left ventricular (LV) pressure overload hypertrophy and beta-adrenergic contractile response. BACKGROUND: Nitric oxide cyclic GMP signaling is postulated to depress vascular growth, but its effects on cardiac hypertrophic growth are controversial. METHODS: Forty control rats and 40 rats with aortic stenosis left ventricular hypertrophy ([LVH] group) were randomized to receive either L-arginine (0.40 g/kg/day) or no drug for 6 weeks. RESULTS: The dose of L-arginine did not alter systemic blood pressure. Animals with LVH had similar LV constitutive nitric oxide synthase (cNOS) mRNA and protein levels, and LV cyclic GMP levels as compared with age-matched controls. In rats with LVH L-arginine treatment led to a 35% increase in cNOS protein levels (p = 0.09 vs untreated animals with LVH) and a 1.7-fold increase in LV cyclic GMP levels (p < 0.05 vs untreated animals with LVH). However, L-arginine treatment did not suppress LVH in the animals with aortic stenosis. In contrast, in vivo LV systolic pressure was depressed in L-arginine treated versus untreated rats with LVH (163 +/- 16 vs 198 +/- 10 mm Hg, p < 0.05). In addition, the contractile response to isoproterenol was blunted in both isolated intact hearts and isolated myocytes from L-arginine treated rats with LVH compared with untreated rats with LVH. This effect was mediated by a blunted increase in peak systolic intracellular calcium in response to beta-adrenergic stimulation. CONCLUSIONS: Left ventricular hypertrophy due to chronic mechanical systolic pressure overload is not characterized by a deficiency of LV cNOS and cyclic GMP levels. In rats with aortic stenosis, L-arginine treatment increased cardiac levels of cyclic GMP, but it did not modify cardiac mass in rats with aortic stenosis. However, long-term stimulation of NO-cyclic GMP signaling depressed in vivo LV systolic function in LVH rats and markedly blunted the contractile response to beta-adrenergic stimulation.

Adrenergic beta-Agonists↗
PubMed1998

Results of a domestic violence training program offered to the staff of urban community health centers. Evaluation Committee of the Philadelphia Family Violence Working Group.

INTRODUCTION: Domestic violence (DV) against women often goes unrecognized by health care providers due to multiple barriers. In an effort to increase screening, identification, and referral for services, the RADAR Training Project was created for the health care staff of 12 federally qualified community health centers (CHCs). METHODS: A two-phase evaluation was conducted to assess the intervention. Phase one evaluated the health care providers' perceived knowledge and comfort pre-training, post-training, and at 3 months follow-up. The second phase included a medical chart review of 4 CHCs to assess the rates of screening, documentation of abuse, assessment of safety, and referrals for help at baseline (6 months pre-training) as compared to the intervention period (6 months post-training). RESULTS: The health care providers' perceived level of knowledge and comfort increased significantly post-training and then later decreased at 3 months follow-up. The rate of screening for DV (25% vs. 5%), suspicion of DV (6% vs. 2%), completion of safety assessments (17% vs. 5%), and referrals (4% vs. 0%) increased significantly between the intervention and baseline periods. However, the rates of documentation of abuse did not change. CONCLUSIONS: This intervention was successful in increasing provider perceived knowledge and comfort; however, comfort decreased at follow-up. Additionally, the rates of screening and referrals increased 6 months post-training. Health care provider training and support and integrated quality assurance mechanisms may be necessary to increase the overall rate of these activities, and to sustain this effort over time. Further study is needed to identify effective methods to increase provider comfort regarding DV screening.

Adolescent↗
PubMed1994

Rescue of a maize mitochondrial cytochrome oxidase mutant by tissue culture.

The maize NCS6 mitochondrial mutation is a partial deletion of the cytochrome oxidase subunit 2 gene (cox2) that survives heteroplasmically in the plant. Mutant mitochondria segregate from normal mitochondria during somatic development giving rise to defective sectors on the plants, including areas of kernel abortion on the ears. Embryos from NCS6 kernels can be rescued by tissue culture. Slowly growing Type II callus derived from one of these embryos has been shown by PCR analysis to be homoplasmic for the mutation, carrying only the defective mitochondrial cox2 gene. Most of the rescued embryos were heteroplasmic for normal and mutant genes and heteroplasmy was maintained in the callus cultures. However, when suspension cultures were initiated from heteroplasmic calli, normal cells were shown to have a selective advantage. When the homoplasmic cox2 mutant callus cultures were placed on regeneration medium, plantlets did not regenerate. Heteroplasmic calli were capable of regeneration under the same conditions. These studies suggest that the functioning of mitochondrial cytochrome oxidase is not essential for growth as callus, but is required for the differentiation and development of plants.

Base Sequence↗
PubMed1993

Effect of ethanol exposure on circulating levels of insulin-like growth factor I and II, and insulin-like growth factor binding proteins in fetal rats.

Maternal ethanol (ETOH) exposure is associated with impaired fetal growth. Because insulin-like growth factors (IGFs) are thought to be important in the regulation of fetal somatic growth, we examined the influence of maternal ETOH exposure on fetal growth and plasma levels of IGF-I, IGF-II, and IGF binding proteins (IGFBPs) in the rat model. Control (A) dams were fed a standard rat chow ad libitum. ETOH (E) consuming dams were fed a 36% ETOH diet, and pair-fed (P) dams were fed isocaloric amounts of a control liquid diet. All animals were killed on day 20 of gestation. Plasma concentrations of IGF-I and -II were determined by radioimmunoassay after formic acid-acetone extraction and heat inactivation of IGFBPs. Levels of IGFBPs in fetal plasma were estimated by Western ligand blotting after protein separation by SDS-PAGE and electrotransfer to nitrocellulose. Membranes were probed with [125I]IGF-I, and IGFBPs were identified by autoradiography, quantified by scanning densitometry and results expressed relative to corresponding IGFBPs in control fetal plasma. Maternal weight gain from conception to 20 days of pregnancy was reduced for E compared to P and A dams (p < 0.05 E vs. P or A). The same pattern was reflected in fetal weight that tended to be lower in P compared with A pups, and was significantly reduced in E pups compared with both groups (p < 0.0001 E vs. P or A). Thus, fetal growth was more retarded in E animals despite equal caloric and protein intake by E and P dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Improved detection of the histamine receptor on human peripheral blood mononuclear cells by crosslinking using tritiated as compared with radioiodinated histamine.

In order to detect histamine receptors on the surface of human peripheral blood mononuclear cells, the cells were incubated in the presence of radiolabelled histamine and then the bifunctional crosslinker disuccimidyl suberate was added in various concentrations. They were then solubilized with sodium dodecyl sulphate, boiled, reduced and the lysate separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both 3H and 125I-radiolabelled ligands bound to a 16 kDa band, to be defined although a much clearer and obviously unequivocal signal was obtained with 3H-labelled histamine. This molecule migrated with the same mass on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a 16 kDa subunit which had been purified on a histamine affinity column from Triton X-100 solubilized mononuclear cells, indicating it to be the ligand-binding subunit for the histamine receptor on these cells. For 3H, fluorography with Entensify was required to obtain an autoradiographic signal. Although 3H took much longer to give a signal than 125I, the considerable background, artefacts and heavy lane trailing seen with [125I] histamine were completely abrogated when [3H]histamine was used. In addition, the distinction between specific and nonspecific binding was more clearly seen using [3H]histamine. The modifications reported here which improve signal detection for 3H should encourage the use of tritiated ligands in radioreceptor crosslinking, particularly those of low molecular weight which might otherwise undergo steric modification due to iodination, this having the potential for interfering with receptor ligand binding.

Autoradiography↗
PubMed1990

Evaluation of a perinatal autopsy protocol: influence of the Prenatal Diagnosis Conference Team.

This study was designed to evaluate changes in the perinatal autopsy following the adoption of a new autopsy protocol. The University of Utah Medical Center has a Prenatal Diagnosis Conference Team composed of obstetricians, pediatricians, geneticists, and other health care professionals. These individuals are involved in the care of patients whose pregnancies are at risk for congenital malformations. An autopsy protocol was designed to increase the interaction of the pathologist with the Prenatal Diagnosis Conference Team in the evaluation of perinatal death. Two years, 1982 and 1987, before and after the protocol was implemented, were selected for retrospective review. The autopsies in 1987 made more specific diagnoses compared with those in 1982. Additional congenital anomalies were diagnosed, and increased numbers of patients were found to have well-described congenital disorders. The number of attempted postnatal autopsy chromosome studies increased and more chromosomal abnormalities were detected. The final autopsy diagnoses made in 1987 have provided more information to the physician for genetic or other patient counseling. After the protocol was adopted, increased numbers of cases were referred to the Medical Center for evaluation at autopsy. More of those who came to autopsy had been evaluated during life by members of the Prenatal Diagnosis Conference Team. Premortem sonograms had been done at an earlier gestational age and a greater number of anomalies were detected. Fewer of the fetuses had intrauterine death and more had pregnancy terminated by induction of labor. The gestational age at delivery declined.

Autopsy↗
PubMed1989

Evidence of free radical (FR) involvement in ischemic colitis.

Early ischemic colitis was induced in rats to evaluate the roles of FRs and intraluminal content. After 30 minutes of ischemia, biopsies for histology, conjugated dienes (CD) and malonaldehyde (M), presumptive marker of lipid peroxidation, were obtained at 0, 30, and 60 minutes reperfusion. Histology was unchanged. CD and M were elevated in ischemic and saline controls, and rose progressively during reperfusion; CD and M were essentially the same as non-ischemic controls during reperfusion with intraluminal corticosteroid (c) and Alcide (A). These agents may be beneficial in early ischemic colitis.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Lithium therapy, hypercalcemia, and hyperparathyroidism.

Lithium is a monovalent cation that influences calcium metabolism in various tissues including the brain, kidney, heart, and parathyroid gland. Mr. A received treatment with lithium for 19 years because this medication proved to be effective in the management of his bipolar illness. However, he developed hypercalcemia, hypertension, and episodes of severe bradyarrhythmia (one of them requiring admission to the medical intensive care unit), with lithium levels within the therapeutic range. An extended endocrine workup showed hyperparathyroidism, with elevated serum parathyroid hormone levels, hypercalcemia, hypocalciuria, and normal serum phosphate levels. These biochemical findings are different from those of primary hyperparathyroidism and are attributed to direct actions of the lithium in the kidney. Discontinuation of the lithium did not result in reversal of the abnormal findings. The patient had surgery, and hyperplasia of the parathyroid gland was found. After parathyroidectomy, the bradyarrhythmia subsided and the patient showed improvement both in his psychiatric condition and hypertension. Preliminary observations in nine other lithium-induced hypercalcemic patients show a high frequency of arrhythmias with bradycardia and conduction defects. These findings suggest that hypercalcemia with lithium increases the risk of cardiac arrhythmia and emphasize the need for regular laboratory and electrocardiographic monitoring of patients on maintenance lithium therapy.

Humans↗
PubMedDate not supplied

"Flat" versus "weighted" reimbursement formulas: a longitudinal analysis of statewide special education funding practices.

Tennessee data were analyzed longitudinally from 1979-80 to 1987-88 in terms of numbers of children placed in a variety of service options. In 1983-84, the Tennessee funding formula was changed from a "flat" rate to a "weighted" formula. The weighted formula was associated with a statistically significant decrease in less restrictive placements and a reliable increase in more restrictive placements. A statewide survey of district special education directors suggested that service needs may have been more likely than monetary incentives to explain the observed changes.

Child↗
PubMedDate not supplied

Glomerulopathic light chain-mesangial cell interactions modulate in vitro extracellular matrix remodeling and reproduce mesangiopathic findings documented in vivo.

Glomerulopathic light chains (LCs) are associated with two distinct mesangiopathies: AL (light-chain-related) amyloidosis and light-chain deposition disease (LCDD) with immunomorphologic features that are well documented in the literature. Even though both conditions are caused by monoclonal LCs, these entities differ dramatically in their morphologic expressions. In AL amyloidosis the mesangial matrix is replaced by amyloid fibrils, while in LCDD the matrix increases as a consequence of deposition of excess extracellular matrix (ECM). The immunomorphologic mesangial alterations observed in biopsy material are closely reproduced in vitro when mesangial cells grown on an artificial matrix are incubated with monoclonal light chains obtained from the urine of patients with either condition. This article summarizes previously reported data, reports new findings, and focuses on integrating all the available information on the subject. When mesangial cells are incubated with LCDD-LCs, production of ECM proteins (collagen IV, laminin, fibronectin, and tenascin) is increased, with maximum effect at 72 hours post LC treatment. A concomitant decrease in collagenase IV activity further accentuates the accumulation of mesangial matrix. These effects are mediated through transforming growth factor-beta (TGF-beta) activation. In contrast, when mesangial cells are incubated with Am-LCs, a decrease in ECM protein production and a stimulatory effect on collagenase IV is observed, which results in matrix degradation and facilitates amyloid deposition. The decreased TGF-beta documented in the literature in this setting precludes adequate matrix repair. These findings substantiate the morphologic alterations observed in renal biopsy specimens and in the in vitro model. Using this in vitro model, it is then possible to delineate the LC interactions with putative receptors at the mesangial cell surface that regulate mesangial cell pathobiologic responses and mesangial matrix homeostasis.

Amyloid↗