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J T Moore

Publications and source records attributed to J T Moore.

At least 37 records · Page 2Linked to original sources
PubMed1998

An orphan nuclear receptor activated by pregnanes defines a novel steroid signaling pathway.

Steroid hormones exert profound effects on differentiation, development, and homeostasis in higher eukaryotes through interactions with nuclear receptors. We describe a novel orphan nuclear receptor, termed the pregnane X receptor (PXR), that is activated by naturally occurring steroids such as pregnenolone and progesterone, and synthetic glucocorticoids and antiglucocorticoids. PXR exists as two isoforms, PXR.1 and PXR.2, that are differentially activated by steroids. Notably, PXR.1 is efficaciously activated by pregnenolone 16alpha-carbonitrile, a glucocorticoid receptor antagonist that induces the expression of the CYP3A family of steroid hydroxylases and modulates sterol and bile acid biosynthesis in vivo. Our results provide evidence for the existence of a novel steroid hormone signaling pathway with potential implications in the regulation of steroid hormone and sterol homeostasis.

Amino Acid Sequence↗
PubMed1997

The development of beta-lactamase as a highly versatile genetic reporter for eukaryotic cells.

We describe in this report that TEM-1 beta-lactamase has several desirable characteristics as a genetic reporter. First, it has no endogenous counterpart in eukaryotic cells and therefore provides a background-free measure of gene expression. Second, because of the uniqueness of the substrate cleavage reaction, a wide variety of substrates which are efficiently cleaved can be synthesized for beta-lactamase. Third, since the assays involve no more than addition of substrate to media, it is possible to continuously monitor a culture without destruction of the cells. Fourth, the enzyme is extremely versatile in that it can be fused to other proteins and retain activity. To demonstrate the versatility of beta-lactamase, we created three forms of the enzyme including secreted, intracellular, and membrane-bound forms of the enzyme, each form having distinct advantages as a reporter system. We also showed that levels of secreted beta-lactamase were proportional to both the levels of transfected DNA, beta-lactamase mRNA, as well as activity of the chloramphenicol acetyl transferase gene controlled by the same promoter, validating the reliability of this reporter. beta-Lactamase thus represents a novel and highly versatile genetic reporter.

Animals↗
PubMed1997

Thoracoscopic excision of mediastinal parathyroid adenomas: a report of two cases and review of the literature.

BACKGROUND: Most abnormal parathyroid glands can be removed through a standard cervical incision; even those in the superior mediastinum. Those located in certain areas of the mediastinum, for example posteriorly or in the aortopulmonic window, historically have required excision through a median sternotomy or thoracotomy. Angioablation is a nonsurgical alternative to management of these lesions. STUDY DESIGN: We present two case reports of mediastinal parathyroid adenomas that were excised thoracoscopically, and review the literature regarding the management of mediastinal parathyroid adenomas. RESULTS: Both patients who underwent precise localization and thoracoscopic excision of their mediastinal parathyroid adenomas had resolution of their hypercalcemia with minimal associated morbidity and shortened recovery periods. CONCLUSIONS: We suggest that thoracoscopic excision of mediastinal parathyroid adenomas is the better means of controlling hypercalcemia secondary to parathyroid adenoma in those patients considered for either median sternotomy, thoracotomy or angiographic ablation where the exact location of the lesion can be established preoperatively.

Adenoma↗
PubMed1997

Applications of S-layers.

The wealth of information existing on the general principle of S-layers has revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from many organisms are capable of recrystallizing as closed monolayers onto solid supports at the air-water interface, on lipid monolayers or onto the surface of liposomes. Particularly their repetitive physicochemical properties down to the subnanometer scale make S-layers unique structures for functionalization of surfaces and interfaces down to the ultimate resolution limit. The following review focuses on selected applications in biotechnology, diagnostics, vaccine development, biomimetic membranes, supramolecular engineering and nanotechnology. Despite progress in the characterization of S-layers and the exploitation of S-layers for the applications described in this chapter, it is clear that the field lags behind others (e.g. enzyme engineering) in applying recent advances in protein engineering. Genetic modification and targeted chemical modification would allow several possibilities including the manipulation of pore permeation properties, the introduction of switches to open and close the pores, and the covalent attachment to surfaces or other macromolecules through defined sites on the S-layer protein. The application of protein engineering to S-layers will require the development of straightforward expression systems, the development of simple assays for assembly and function that are suitable for the rapid screening of numerous mutants and the acquisition of structural information at atomic resolution. Attention should be given to these areas in the coming years.

Bacteria↗
PubMed1997

Explantation of silicone breast implants.

Silicone gel-filled breast implants have been employed clinically for decades for aesthetic augmentation or postmastectomy reconstruction. Most patients and surgeons attest to the efficacy and safety of these devices. However, more recently in the medical literature and popular media, silicone gel-filled breast implants have been claimed to incite an array of clinical sequelae such as capsular formation, granulomatous disease, arthritis, arthralgia, fibromyalgia, autoimmune collagen vascular disease, human adjuvant disease, siliconosis, silicone-related disease, and silicone implant-associated syndrome. During a recent 24-month period, 25 referred patients underwent explantation of bilateral silicone gel-filled prostheses at the University of South Alabama. Patient-reported symptoms and signs included mastodynia, arthralgia, fibromyalgia, xerophthalmia, xerostomia, hypesthesia, and amblyopia. Clinical examination and mammography were reliable in diagnosing implant rupture, but only re-exploration reliably detected implant leakage. Most patients underwent concurrent replacement with saline-filled devices. Histopathologic analyses of all tissue samples revealed chronic inflammation. Subjective improvement of patient-reported symptoms and signs occurred over the course of months postoperatively. There was no mortality associated with explantation, with or without replacement, but an overall morbidity incidence of 20 per cent (5 of 25) was observed. Predicated upon review of the available scientific literature and analysis of this modest number of patients, the following perspectives are germane. 1) A small cohort of patients of status postimplantation of silicone gel-filled devices will manifest chronic morbidity. Identifying such patients prospectively remains problematic. 2) Whether or not silicone gel incites adverse systemic phenomena is unproven, although it has been implicated. 3) Symptomatic patients with silicone gel-filled implants in place should be considered for removal, with full knowledge of the morbidity associated with revisional procedures. 4) Patients currently undergoing breast augmentation or reconstruction employing prosthetics are perhaps best served by insertion of saline-filled devices. 5) Patient-physician dialogue regarding the risk-benefit analysis of prosthetic implantation is imperative. Patients consenting to such procedures must be willing to assume risks.

Adult↗
PubMed1996

Protein-protein interactions involving T4 phage-coded deoxycytidylate deaminase and thymidylate synthase.

The enzymes deoxycytidylate deaminase (EC) and thymidylate synthase (EC) are functionally associated with one another, since they catalyze sequential reactions. In T4 coliphage infection the two enzymes are found in dNTP synthetase, a multienzyme complex for deoxyribonucleotide biosynthesis. Protein-protein interactions involving the phage-coded forms of these two enzymes have been explored in three experiments that use the respective purified protein as an affinity ligand. First, an extract of radiolabeled T4 proteins was passed through a column of immobilized enzyme (either dTMP synthase or dCMP deaminase), and the specifically bound proteins were identified. Second, two mutant form of dCMP deaminase (H90N and H94N), altered in presumed zinc-binding sites, were analyzed similarly, with the results suggesting that some, but not all, interactions require normal structure near the catalytic site. Third, affinity chromatography using either enzyme as the immobilized ligand, revealed interactions between the two purified enzymes in the absence of other proteins. In these experiments we noted a significant effect of dCTP, an allosteric modifier of dCMP deaminase, upon the interactions.

Bacteriophage T4↗
PubMed1996

The anti-human immunodeficiency virus agent 3'-fluorothymidine induces DNA damage and apoptosis in human lymphoblastoid cells.

Patients infected with the human immunodeficiency virus experienced severe hematopoietic toxicity after treatment with the deoxynucleoside analog 3'-fluorothymidine (FLT). Using several methods for the analysis of genome integrity, including histochemical staining of the 3' ends of DNA and both conventional and pulsed-field agarose gel electrophoresis, we demonstrated that FLT caused extensive DNA fragmentation in CEM cells that was not observed when these cells were treated with other, less toxic thymidine analogs. In addition, a distinctive pattern of small DNA fragments that is characteristic of cells in the process of programmed cell death was observed in the genomic DNA of CEM cells treated with FLT. We conclude that FLT induces DNA fragmentation and apoptosis in a human cell line of hematopoietic origin, and we offer this observation as a possible explanation for the severe toxicity of FLT observed in vivo.

Antineoplastic Agents, Phytogenic↗
PubMed1996

Metastatic breast carcinoma presenting as cholecystitis.

We report two cases of metastatic breast cancer presenting as cholecystitis. Each patient had undergone a mastectomy years earlier. Biopsy of the gallbladder removed during cholecystectomy revealed metastatic infiltrating ductal carcinoma in one patient and infiltrating lobular carcinoma in the other.

Aged↗
PubMed1994

Identification of a site necessary for allosteric regulation in T4-phage deoxycytidylate deaminase.

An allosteric inhibitor of dCMP deaminase, dTTP, forms a photolabile covalent bond with T4-phage dCMP deaminase in the presence of UV light at 254 nm. The importance of the methyl group in this process is supported by the findings that dUTP, also an allosteric inhibitor, does not photofix to the enzyme and that tritium is released from [methyl-3H dTTP during the course of the photofixation. That the bond formed is photolabile is demonstrated by the fact that tritium is released by about 10-fold over the amount of nucleotide that is photofixed. The amino acid that covalently binds dTTP in T4-dCMP deaminase was identified as Phe112. On conversion of Phe112 to an alanine by site-directed mutagenesis, there was a dramatic change in the enzyme's response to its allosteric effectors when measured early in the reaction, in that the mutant enzyme was as active as the wild-type even in the absence of dCTP and was only weakly inhibited by dTTP. However, after 10-15% of the substrate had been deaminated, the reaction rate fell off rather markedly, indicating either that an inhibitor was being accumulated on the enzyme or that the enzyme was being irreversibly inactivated with time. That the latter was not the case was shown by the addition of dCTP to the reaction, which restored the rate to that expected when it was present initially. Furthermore, we showed that, consistent with the observed loss of allosteric regulation by dCTP and dTTP, the affinity of the mutant enzyme for dTTP and dCTP as determined by binding studies was greatly reduced relative to the wild-type enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1994

Relationship between sleep spindles and hypersomnia.

Sleep spindles (SS) and K complexes constitute the physiological markers of stage 2 sleep. Because sleep allows a spontaneous thalamic manifestation in the form of SS, one could hypothesize that there is some kind of relationship between SS and the complaint of hypersomnia. To investigate this possible relationship we compared nonhypersomnolent subjects with hypersomnolent patients who carried a diagnosis of narcolepsy or idiopathic hypersomnia. SS were counted in well-defined nocturnal stage 2 sleep segments, and the average SS density (number of SS in stage 2/minute stage 2) was tabulated for the entire night. Agreement between two independent scores was higher than 95%. The results show that the average SS density is higher in both cerebral hemispheres in the hypersomnolent group, especially in the idiopathic hypersomnia patients. At the beginning and at the end of the nocturnal sleep time, SS density is increased in this group compared with the normal one. These findings support the complaint of hypersomnia, mainly in idiopathic hypersomnia patients. This is in agreement with the notion that SS are generated by thalamic structures that serve a gatekeeping function during nonrapid eye movement sleep, and further suggests that their relative abundance expresses the power of that control.

Adolescent↗
PubMed1994

Extramedullary hematopoiesis during therapy with granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor is a glycoprotein that promotes the proliferation and differentiation of neutrophils. It also results in an increase in circulating hematopoietic progenitor cells. We describe two cases of extramedullary hematopoiesis in patients receiving granulocyte colony-stimulating factor with chemotherapy for metastatic breast cancer.

Adult↗
PubMed1993

T4-phage deoxycytidylate deaminase is a metalloprotein containing two zinc atoms per subunit.

Deoxycytidylate (dCMP) deaminase, a hexameric allosteric enzyme induced on infection of Escherichia coli by bacteriophage T4, was shown to contain two atoms of zinc per subunit by atomic absorption spectroscopy. One zinc appears to be involved in catalysis, as described for adenosine deaminase (Sharaff, A. J., Wilson, D. K., Chang, Z., and Quiocho, F. A. (1992) J. Mol. Biol. 226, 917-921) and cytidine deaminase (Yang, C., Carlow, D., Wolfenden, R., and Short, S. A. (1992) Biochemistry 31, 4168-4174). This thesis is supported by the finding that the enzyme loses about 80% of its activity in the presence of o-phenanthroline. It has also been found that zinc is released when the enzyme is denatured in the presence of the metallochromic indicator, 4-(2-pyridylazo)resorcinol. Renaturation of the deaminase to an active form occurred in the presence but not in the absence of zinc. The second atom of zinc is proposed to be located in a region of T4-dCMP deaminase that resembles a zinc finger. This region, which has the sequence His-X3-Cys-X14-His-X3-His, would represent a zinc-binding motif that has not been described previously.

Amino Acid Sequence↗
PubMed1993

Overcoming inclusion body formation in a high-level expression system.

Attempts at overexpressing T4-phage deoxycytidylate deaminase using the pET3c/BL21(DE3)/pLysS system resulted in this enzyme being part of an inactive inclusion-body complex. However, by employing an enriched growth medium it was found that the deaminase could be induced in a soluble active form to at least 20% of this organism's cellular protein. Insoluble inclusion bodies were obtained with less rich media. This procedure was employed successfully with other highly expressed proteins that formed inclusion bodies. The use of a rich growth medium during the course of protein induction may be a valuable adjunct to limiting inclusion body formation with this as well as other expression systems.

Bacteriophage T4↗
PubMed1992

[Treatment with continuous positive nasal pressure in obstructive sleep apnea syndrome].

BACKGROUND: The collapse of the soft tissues of the upper airway during sleep is decisive in the pathogenesis of the obstructive sleep apnea syndrome. The administration of an air flow of adjustable pressure through the nose is efficient to overcome the obstruction and favor respiration without apnea. METHODS: Twenty-two patients with obstructive sleep apnea syndrome were treated with continuous positive pressure of the upper airway with the aim of evaluating the effect of this treatment on sleep, respiration and cardiac rhythm following the first night of treatment. RESULTS: Following the night of treatment an increase of the III, IV states and sleep REM with a shortening of REM latency was observed. The number of apneas diminished drastically thus improving cardiac arrhythmias detected in the basal study. CONCLUSIONS: Treatment of the upper airway with continuous positive pressure is efficient not only for the correction of apneas and cardiac arrhythmia but also for the consolidation of a normal sleep cycle.

Adult↗
PubMed1991

[The multiple sleep latency test in the diagnosis of narcolepsy and idiopathic hypersomnia].

The diagnostic differential between narcolepsy and idiopathic hypersomnia may be difficult in those cases which clinically manifest only hypersomnia and the nocturnal polygraphic study does not show any differences between both diseases, particularly when the beginning of REM sleep is not presented in narcoleptic patients. The multiple sleep latency test is an objective test of daytime hypersomnia in both diseases. Moreover, if 2 or more REM periods are registered altogether in the 4 or 5 siestas studied, the test is highly suggestive of narcolepsy and permits sure differentiation with idiopathic hypersomnia. In the present study, the multiple sleep latency test permitted the diagnosis of the cases of oligosymptomatic narcolepsy and absence of the beginning of REM sleep.

Adult↗
PubMed1990

Characterization of IMP-E3, a gene active during imaginal disc morphogenesis in Drosophila melanogaster.

The steroid hormone 20-hydroxyecdysone (20-HE) induces imaginal discs to form adult appendages in Drosophila. We have isolated a set of six ecdysone-responsive genes that apparently encode disc cell-surface or secreted proteins. Transcripts from one of these genes, IMP-E3, accumulate rapidly within 1-2 h in response to hormone. Developmentally, IMP-E3 transcripts reach maximum levels during the first stages of metamorphosis (white prepupae, WPP) and are primarily limited to imaginal tissues. Transcripts are also present during embryogenesis (0-3 h and 12-18 h). Two different-sized transcripts (1.2 and 1.4 kb) result from differential polyadenylation, with the larger transcript predominating in WPP. The conceptual IMP-E3 protein contains a signal peptide, an RGD sequence, and a potential glycosylphosphatidylinositol anchor. We speculate that the protein provides a transient cue important for imaginal disc morphogenesis.

Amino Acid Sequence↗