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Biomedical subjects

S Terry

Publications and source records attributed to S Terry.

At least 19 recordsLinked to original sources
PubMed2006

Complex regulation of human androgen receptor expression by Wnt signaling in prostate cancer cells.

beta-Catenin, a component of the Wnt signaling pathway, is a coactivator of human androgen receptor (hAR) transcriptional activity. Here, we show that Wnt signaling also influences androgen-mediated signaling through its ability to regulate hAR mRNA and protein in prostate cancer (PCa) cells. Three functional LEF-1/TCF binding sites lie within the promoter of the hAR gene as shown by CHIP assays that captured beta-catenin-bound chromatin from Wnt-activated LNCaP cells. Chimeric reporter vectors that use the hAR gene promoter to drive luciferase expression confirmed that these LEF-1/TCF binding elements are able to confer robust upregulation of luciferase expression when stimulated by Wnt-1 or by transfection with beta-catenin and that dominant-negative TCF or mutations within the dominant TCF-binding element abrogated the response. Semi-quantitative and real time RT-PCR assays confirmed that Wnt activation upregulates hAR mRNA in PCa cells. In contrast, hAR protein expression was strongly suppressed by Wnt activation. The reduction of hAR protein is consistent with evidence that Wnt signaling increased phosphorylation of Akt and its downstream target, MDM2 that promotes degradation of hAR protein through a proteasomal pathway. These data indicate that the hAR gene is a direct target of LEF-1/TCF transcriptional regulation in PCa cells but also show that the expression of the hAR protein is suppressed by a degradation pathway regulated by cross-talk of Wnt to Akt that is likely mediated by Wnt-directed degradation of the B regulatory subunit of protein phosphatase, PP2A.

Binding Sites↗
PubMed2004

Pregnancy and obstetrical outcomes in pseudoxanthoma elasticum.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is a genetic multisystem disorder characterized by calcified dystrophic elastic fibres in skin, retina and arteries. Much of the earlier literature on pregnancy in PXE contained reports of severe complications, leading some healthcare providers to advise women with PXE against becoming pregnant and some women with PXE to avoid pregnancy. OBJECTIVES: To evaluate the obstetrical outcomes and the incidence of pregnancy complications in women with PXE and to determine if pregnancy is associated with an adverse effect on the course of the disease. METHODS: Women with PXE (n = 407) answered detailed questionnaires regarding reproductive history and pregnancy as well as the course of their disease. The frequency of reported pregnancy outcomes and complications was determined. Severity indices for the major clinical manifestations of PXE were developed and correlated with gravidity of affected women aged 40 years or over. RESULTS: Among the 306 respondents with PXE who had ever been pregnant, there were 795 pregnancies. Of these, 83% ended in live births and 1% in stillbirth. The median birth weight was within the normal range and the incidence of low birth weight for gestation was low. Hypertension occurred in 10% of pregnancies, gastric bleeding and retinal complications in < 1%, and 12% of pregnancies were associated with worsening of skin manifestations. There was no effect of gravidity and clinical severity on cutaneous (P = 0.07), ocular (P = 0.59) or cardiac (P = 0.42) manifestations of PXE in women aged 40+ years, nor did ever having been pregnant adversely affect these clinical severity indices. Of the 101 women who had never been pregnant, 17% made the decision because they were advised against becoming pregnant by a healthcare professional and 11% did not become pregnant because they feared an adverse outcome either in their pregnancy or disease. CONCLUSIONS: PXE is not associated with markedly increased fetal loss or adverse reproductive outcomes. The incidence of gastric bleeding, although probably higher than in the unaffected population, is much lower than previously reported, and retinal complications are uncommon. Although a few pregnancies were associated with worsening of skin manifestations, there was no correlation of either gravidity or ever having been pregnant with ultimate severity of skin, ocular or cardiovascular manifestations. There is no basis for advising women with PXE to avoid becoming pregnant, and most pregnancies in PXE are uncomplicated.

Adolescent↗
PubMed2001

Informed consent for population-based research involving genetics.

Bridging the gap between gene discovery and our ability to use genetic information to benefit health requires population-based knowledge about the contribution of common gene variants and gene-environment interactions to the risk of disease. The risks and benefits associated with population-based research involving genetics, especially lower-penetrance gene variants, can differ in nature from those associated with family-based research. In response to the urgent need for appropriate guidelines, the Centers for Disease Control and Prevention formed a multidisciplinary group to develop an informed consent approach for integrating genetic variation into population-based research. The group used expert opinion and federal regulations, the National Bioethics Advisory Commission's report on research involving human biological materials, existing consent forms, and literature on informed consent to create suggested language for informed consent documents and a supplemental brochure. This language reflects the premise that the probability and magnitude of harm, as well as possible personal benefits, are directly related to the meaning of the results for the health of the participant and that appropriate disclosures and processes for obtaining consent should be based on an assessment at the outset of the likelihood that the results will generate information that could lead directly to an evidence-based intervention. This informed consent approach is proposed to promote discussion about how best to enable potential participants to make informed decisions about population-based research involving genetics and to suggest issues for consideration by research sponsors, institutional review boards, and investigators.

DNA↗
PubMed2001

The placenta in pseudoxanthoma elasticum: clinical, structural and immunochemical study.

Pseudoxanthoma elasticum (PXE) is a rare genetic disorder clinically characterized by skin, cardiovascular and eye manifestations, mainly due to calcification and fragmentation of elastic fibres. Although infrequent, complications during pregnancy in women affected by PXE have been reported. The aim of the present study was to compare structural features of placentae at term from 14 control and 15 PXE-affected women, in order to better understand if and how abnormal mineral and/or matrix accumulation might affect placental function in PXE. In all cases, pregnancy, fetus growth and delivery were normal. Both gross and light microscopy examination did not reveal dramatic differences between placentae of PXE patients and controls, with regard to weight, dimensions, infarcts, thrombi, inflammatory lesions or vessels. However, necrotic changes and mineralization appeared statistically more pronounced in PXE. By electron microscopy the most remarkable differences between PXE and control placentae were observed in the localization and morphology of mineral precipitates; a significant higher deposition of mineral precipitates was observed associated with the "matrix"-type fibrinoid and among collagen fibrils, especially on the maternal side. Immunocytochemistry revealed the presence of vitronectin and fibronectin associated with the PXE-specific mineralizations and the absence of mineralization on the small and scarce elastic fibres in either controls or in PXE.

Adult↗
PubMed2000

Mutations in a gene encoding an ABC transporter cause pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized by calcification of elastic fibres in skin, arteries and retina that results in dermal lesions with associated laxity and loss of elasticity, arterial insufficiency and retinal haemorrhages leading to macular degeneration. PXE is usually found as a sporadic disorder, but examples of both autosomal recessive and autosomal dominant forms of PXE have been observed. Partial manifestations of the PXE phenotype have also been described in presumed carriers in PXE families. Linkage of both dominant and recessive forms of PXE to a 5-cM domain on chromosome 16p13.1 has been reported (refs 8,9). We have refined this locus to an 820-kb region containing 6 candidate genes. Here we report the exclusion of five of these genes and the identification of the first mutations responsible for the development of PXE in a gene encoding a protein associated with multidrug resistance (ABCC6).

ATP-Binding Cassette Transporters↗
PubMed2000

Mutations in ABCC6 cause pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disorder of the connective tissue. PXE patients frequently experience visual field loss and skin lesions, and occasionally cardiovascular complications. Histopathological findings reveal calcification of the elastic fibres and abnormalities of the collagen fibrils. Most PXE patients are sporadic, but autosomal recessive and dominant inheritance are also observed. We previously localized the PXE gene to chromosome 16p13.1 (refs 8,9) and constructed a physical map. Here we describe homozygosity mapping in five PXE families and the detection of deletions or mutations in ABCC6 (formerly MRP6) associated with all genetic forms of PXE in seven patients or families.

ATP-Binding Cassette Transporters↗
PubMed1999

Pseudoxanthoma elasticum maps to an 820-kb region of the p13.1 region of chromosome 16.

We have performed linkage analysis on 21 families with pseudoxanthoma elasticum (PXE) using 10 polymorphic markers located on chromosome 16p13.1. The gene responsible for the PXE phenotype was localized to an 8-cM region of 16p13.1 between markers D16S500 and D16S3041 with a maximum lod score of 8.1 at a recombination fraction of 0.04 for marker D16S3017. The lack of any locus heterogeneity suggests that the major predisposing allele for the PXE phenotype is located in this region. Haplotype studies of a total of 36 PXE families identified several recombinations that further confined the PXE gene to a region (< 1 cM) between markers D16S3060 and D16S79. This PXE locus was identified within a single YAC clone and several overlapping BAC recombinants. From sequence analysis of these BAC recombinants, it is clear that the distance between markers D16S3060 and D16S79 is about 820 kb and contains a total of nine genes including three pseudogenes. We predict that mutations in one of the expressed genes in the locus will be responsible for the PXE phenotype in these families.

Alleles↗
PubMed1999

A structural and transcription pattern for variant surface glycoprotein gene expression sites used in metacyclic stage Trypanosoma brucei.

African trypanosomes first express the variant surface glycoprotein (VSG) at the metacyclic stage in the tsetse fly vector, in preparation for transfer into the mammal. Metacyclic (M)VSGs comprise a specific VSG repertoire subset and their expression is regulated differently from that of bloodstream VSGs, involving exclusively transcriptional regulation during the life cycle. To identify basic structural and functional features that may be common to MVSG telomeric transcription units, we have characterized the anatomy and transcription of the telomere containing the ILTat 1.61 MVSG gene. This telomere contains pseudogenes of the ESAG1 and ESAG9 families found in bloodstream VSG transcription units. The 1.61 MVSG occupies a monocistronic transcription unit and is transcriptionally controlled through the life cycle. The 1.61, and also the 1.22, MVSG transcription initiation site sequences resemble eukaryotic initiator elements. Sequence comparison reveals that four out of five characterized MVSG expression sites have a conserved region 2.0-4.7 kb long upstream of the MVSG. In some cases, this region contains not only the transcription initiation site that we have observed to be active in fly-transmitted trypanosomes but also, upstream, another sequence, described elsewhere as a 'putative promoter' for the MVAT set of M/VSGs (Nagoshi YL, Alarcon CM, Donelson JE. A monocistronic transcript for a trypanosome variant surface glycoprotein, Mol Biochem Parasitol 1995;72:33-45). In fly-transmitted trypanosomes, the latter element is transcriptionally silent. Our analysis of the structure of MVSG telomeres suggests that metacyclic expression sites arose from bloodstream expression sites.

Animals↗
PubMed1999

Periocular accumulation of timolol and betaxolol in glaucoma patients under long-term therapy.

PURPOSE: To determine if betaxolol or timolol is present in measurable concentration in the Tenon capsule in patients under long-term topical therapy. METHODS: Small (1-cc) specimens of Tenon capsule were removed at the time of filtering surgery from 15 glaucoma patients under long-term preoperative topical therapy, nine of whom had been treated with timolol and six of whom had been receiving betaxolol. Methanol extracts of these tissue samples were analyzed quantitatively for the presence of either beta-adrenergic antagonist by high-performance liquid chromatography. RESULTS: Drug was detected in every specimen. A mean total of 2.6 (range, 0.1-30.0) microg of betaxolol was detected per 1-cc specimen. CONCLUSION: Timolol and betaxolol penetrate the conjunctiva and accumulate in the Tenon capsule. In patients under long-term therapy, the periocular tissue can accumulate a greater quantity of beta-antagonist than is present in a daily dosage of applied eyedrops, manyfold higher than the maximal intraocular concentration.

Adrenergic beta-Antagonists↗
PubMed1993

Currently recommended oral regimens for ritodrine tocolysis result in extremely low plasma levels.

OBJECTIVE: Our aim was to compare plasma drug levels in patients receiving ritodrine intravenously with those in patients receiving ritodrine orally at recommended dosages. STUDY DESIGN: Plasma samples from 20 pregnant patients treated with intravenous ritodrine (50 to 300 micrograms/min), 9 patients treated with oral ritodrine only (60 to 120 mg per 24 hours), and 9 patients treated first with intravenous and subsequently with oral ritodrine were analyzed for ritodrine concentration with the use of high-performance liquid chromatography. RESULTS: Average plasma ritodrine levels of patients receiving different intravenous dosages ranged from 27.8 +/- 3.5 to 113.3 +/- 38.8 ng/ml. Levels during oral therapy ranged between 9.8 +/- 3.2 and 13.8 +/- 4.4 ng/ml. In both modes of drug delivery, concentrations were significantly correlated with doses. In patients treated first with intravenous ritodrine and subsequently with the oral form, plasma concentrations during oral therapy averaged 27.7% +/- 18.8% of those obtained during intravenous infusion. CONCLUSION: Subtherapeutic plasma concentrations might be responsible for the failure to demonstrate clinical benefits of oral ritodrine in prevention of recurrent preterm labor. A twofold to threefold increase in the maximum recommended oral dosage of ritodrine should be considered, especially for patients who had previously required relatively high intravenous infusion rates (> 100 micrograms/min).

Administration, Oral↗
PubMed1992

Combined no-stitch phacoemulsification cataract extraction with foldable silicone intraocular implant and holmium laser sclerostomy followed by 5-FU injections.

In an attempt to overcome some of the problems associated with combined cataract extraction and glaucoma filtration surgery, we attempted a new combined procedure: a small-incision phacoemulsification cataract removal with placement of a silicone foldable implant and no-stitch closure combined with a holmium laser sclerostomy in an adjacent quadrant, followed by injections of 5-fluorouracil.

Aged↗
PubMed1991

Specificity and effects of host resistance on the African tick Rhipicephalus zambeziensis (Acarina: Ixodidae).

Repeated infestations of the rabbit with adult Rhipicephalus zambeziensis ticks resulted in a ten-fold reduction in engorgement weight of adult ticks and a significant decline in engorgement weight of nymphs. There was no evidence of cross-resistance against the South African bont tick, Amblyomma hebraeum. Immunization of rabbits with crude extracts of whole-tick protein significantly influenced engorgement weights and oviposition rates of adult R. zambeziensis. Histological studies of tissues from R. zambeziensis adults fed on resistant rabbits showed severe gut damage; this was associated with the binding of host IgG to mid-gut cells.

Analysis of Variance↗
PubMed1983

Structure-activity relationship in the mast cell degranulating capacity of neurotensin fragments.

The mast cell degranulating capacity of neurotensin and three of its fragments was examined. In Tyrode solution (137 mM NaCl, 2.7 mM KCl, 0.4 mM NaH2PO4, 1.4 mM CaCl2, 1 mM MgCl2, 10 mM Hepes, 5.6 mM glucose, pH 7.4), neither intact neurotensin nor its C-terminal tripeptide (Tyr-Ile-Leu) caused any release of histamine. Concentrations of neurotensin exceeding 10(-4)M did cause histamine release but through lysis of the cells. The C-terminal hexa- and octapeptides of neurotensin (Arg-Arg-Pro-Tyr-Ile-Leu and Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu, respectively) induced a non-cytolytic release of histamine with the latter peptide being more active (ED50 = 90 microM for the hexapeptide and 13 microM for the octapeptide). This release was not affected by the C-terminal tripeptide. It was found to be calcium-dependent and was inhibited by the anti-allergic drug, disodium cromoglycate. Phosphatidylserine did not enhance release of histamine and saturation of the immunoglobulin E (IgE) receptors did not inhibit it.

Animals↗
PubMed1982

Enhancement of phagocytosis by neurotensin, a newly found biological activity of the neuropeptide.

Specific binding of neurotensin (NT) to mouse peritoneal thioglycollate-elicited macrophages and macrophages differentiated in vitro from bone marrow cells was demonstrated and characterized. NT binding to these phagocytes modulated their phagocytic capacity in a biphasic manner. At concentrations of 10(-14) to 10(-9) M NT, a dose-dependent augmentation of phagocytosis (up to 2-fold) was observed. Further increases in the concentration of NT resulted in a gradual decrease of the augmented response until the basal phagocytic activity (in the absence of NT) was reached. Three partial sequences of NT, NT (8-13), NT (6-13) and NT (1-10), were also effective in augmenting the phagocytic response of thioglycollate elicited macrophages, but the maximal effect was attained at about 10(-7) M and stayed at that level up to a concentration of 10(-5) M. The activity of the three NT partial sequences was comparable to that of substance P and tuftsin. Scatchard analysis of (3H)NT binding to macrophages suggested the existence of two populations of binding sites, a major population of relatively low affinity binding sites and a small population of high affinity binding sites. NT (8-13), NT (6-13), substance P and tuftsin competed with (3H)NT binding to the low affinity sites with a comparable KI to that of NT. NT (1-10) did not compete for the binding at the low affinity sites. It is suggested that NT binding to the high affinity sites leads to enhancement of phagocytosis, whereas its binding to the low affinity sites leads to inhibition of the augmented response. However, the low affinity sites are the sites of interaction of NT (8-13), NT (6-13), substance P and tuftsin with the phagocytes and their saturation with the peptides leads to augmentation of phagocytosis.

Amino Acid Sequence↗