PubMed Health⌕ Search

Biomedical subjects

J Moseley

Publications and source records attributed to J Moseley.

At least 19 recordsLinked to original sources
PubMed2001

Familial intrahepatic cholestasis 1: studies of localization and function.

Mutations in the FIC1 gene constitute the molecular defect in familial intrahepatic cholestasis I (Fic1 [Byler's disease]) and benign recurrent intrahepatic cholestasis. This report describes the localization of Fic1 in rat liver and intestine, as well as biochemical and transfection studies that support its function as an energy-dependent aminophospholipid translocase. Immunocytochemistry of rat liver and immunoblotting of membrane fractions localized Fic1 to the canalicular, but not basolateral, plasma membrane domain. In the small intestine, Fic1 was localized to the apical membrane of epithelial cells. The distribution of Fic1 in liver plasma membrane fractions from control and taurocholate-treated rats correlated positively with adenosine triphosphate (ATP)-dependent aminophospholipid (phosphatidyl-serine) translocase activity. In canalicular membrane vesicles, translocase activity had an initial velocity of 3.3 nmol phosphatidylserine (PS) translocated per milligram of protein per minute and a K(m) (ATP) = 1.2 mmol/L; was inhibited by vanadate, N-ethylmaleimide, sodium azide, and calcium; and was unidirectional (i.e., from the outer to the inner canalicular plasma membrane leaflet). Transient transfection of CHOK1 cells with FIC1 cDNA resulted in appearance of FIC1 in membrane preparations and energy-dependent PS translocation in cells. These studies indicate that FIC1 is a canalicular P-type ATPase that participates in maintaining the distribution of aminophospholipids between the inner and outer leaflets of the plasma membrane. How this process produces cholestasis is under study.

Adenosine Triphosphatases↗
PubMed2001

Bone anabolic effects of sonic/indian hedgehog are mediated by bmp-2/4-dependent pathways in the neonatal rat metatarsal model.

A neonatal rat metatarsal organ culture model has been employed to study the anabolic effects of Sonic/Indian hedgehog and BMP-4. In this culture system, a significant increase in endochondral ossification is measured by an increase in length of mineralized bone, after daily treatment for 7 days with Sonic hedgehog protein (Shh-N). Previous evidence indicated that PTH related protein (PTHrP) is a critical target of hedgehog function in endochondral ossification. Using a PTHrP blocking antibody, it is shown that hedgehog mediates this activity via pathways other than through PTHrP. A dose-related increase in endochondral ossification is observed when metatarsals are treated with 25 ng/ml recombinant human bone morphogenetic protein 4 (BMP-4). However, this activity is not evident at higher doses of BMP-4 (200 ng/ml). High doses of BMP-4 resulted in increased expression of noggin messenger RNA and cotreatment of noggin and Shh-N resulted in reversal of the anabolic action of Shh-N. This observation suggests that BMP-4 signaling can influence the Shh-N mediated increase in endochondral ossification. Finally, we show that the Shh-N and BMP-4 mediated increase in endochondral ossification is reversed by treatment with antisense oligonucleotides targeted against Cbfa1. Thus, this report identifies Shh-N as an inducer of endochondral ossification that mediates its effect via BMP-4 and Cbfa1-dependent pathways.

Animals↗
PubMed2000

The Crd1 gene encodes a putative di-iron enzyme required for photosystem I accumulation in copper deficiency and hypoxia in Chlamydomonas reinhardtii.

Chlamydomonas reinhardtii adapts to copper deficiency by degrading apoplastocyanin and inducing Cyc6 and Cpx1 encoding cytochrome c(6) and coproporphyrinogen oxidase, respectively. To identify other components in this pathway, colonies resulting from insertional mutagenesis were screened for copper- conditional phenotypes. Twelve crd (copper response defect) strains were identified. In copper-deficient conditions, the crd strains fail to accumulate photosystem I and light-harvesting complex I, and they contain reduced amounts of light-harvesting complex II. Cyc6, Cpx1 expression and plastocyanin accumulation remain copper responsive. The crd phenotype is rescued by a similar amount of copper as is required for repression of Cyc6 and Cpx1 and for maintenance of plastocyanin at its usual stoichiometry, suggesting that the affected gene is a target of the same signal transduction pathway. The crd strains represent alleles at a single locus, CRD1, which encodes a 47 kDa, hydrophilic protein with a consensus carboxylate-bridged di-iron binding site. Crd1 homologs are present in the genomes of photosynthetic organisms. In Chlamydomonas, Crd1 expression is activated in copper- or oxygen-deficient cells, and Crd1 function is required for adaptation to these conditions.

Amino Acid Sequence↗
PubMed1999

Subjectivity in interpretation of portal films.

PURPOSE: We have measured the variability in identifying geometric errors and the variability in clinical decision making when using portal films. METHODS AND MATERIALS: Eight observers (four radiation oncologists and four radiation therapists) viewed 40 film pairs from 40 different patients. All films, which were acquired using conventional simulator and portal film cassettes, were selected retrospectively from a large clinical database. The observers compared the simulator and portal films under standard conditions, identified the field placement errors, and decided whether adjustments in treatment were required. In addition, all films were digitized and the field placement errors were measured objectively using image registration software. RESULTS: There was much variability in identifying field placement errors and even more variability in the number of recommended adjustments. The field placement errors identified by the different observers differed by up to 50 mm for the same film pair. The number of adjustments of treatment or block position recommended by the observers also varied between 8 and 25 for the same set of films. The average field placement error, before correction, for AP lung, AP pelvis, and lateral pelvis films was 5.7 mm, 6.3 mm, and 8.9 mm, while the average error after correction (i.e., correcting all errors identified by the observers) was 5.5 mm, 4.9 mm, and 5.7 mm, respectively. Thus, for lateral pelvis films, where the initial errors were larger, the observers were able to make an improvement in patient setup. CONCLUSIONS: The results suggest that human observers have difficulty identifying field placement errors accurately when the errors are around 5 mm or smaller. Although there is some evidence that experience influenced the performance of the observers, the effect of experience is not large. In routine clinical environments, the use of visual inspection will detect large field placement errors. However, tools other than visual inspection will be required if field placement errors 5 mm or smaller are to be identified accurately.

Decision Making↗
PubMed1997

Temporal expression of PTHrP during endochondral bone formation in mouse and intramembranous bone formation in an in vivo rabbit model.

Expression of parathyroid hormone-related protein (PTHrP) messenger RNA (mRNA) and protein was investigated throughout the developmental progression of endochondral bone formation in mouse and intramembranous bone formation in an in vivo model in rabbit, using in situ hybridization and immunohistochemistry. Endochondral bone formation was investigated in a developing embryo, newborn, and adult mouse. In fetal long bones through to newborn (day 7), PTHrP mRNA and protein were consistently expressed in chondrocytes within the proliferative, transitional, and hypertrophic zones. In addition, high levels of PTHrP were also detected in osteoblasts on the surface of trabecular bone surfaces. Similarly, at the adult stage (week 7), PTHrP mRNA and protein were consistently expressed in chondrocytes at epiphyseal ends of the subarticular cartilage, within cortical periosteum, as well as in osteoblasts located at the metaphyseal trabecular bone surfaces. Using an in vivo intramembranous bone formation model in rabbits, expression of PTHrP mRNA and protein was demonstrated in preosteoblasts prior to trabecular bone formation (1-week bone harvest). As bone formed (2-, 3-, and 4-week bone tissue harvests), PTHrP mRNA and protein were highly expressed in actively synthesizing osteoblasts and in those osteocytes embedded within the superficial layers of the bone matrix. Lining osteoblasts and osteocytes buried deeply in the bone matrix displayed weak or no signal for PTHrP. The pattern of spatial and temporal expression of PTHrP demonstrated in cartilage cells and osteoblasts in the two systems suggests an important role of PTHrP in both endochondral and intramembranous bone formation.

Animals↗
PubMed1994

A semiautomatic method for registration of portal images.

A method to register pairs of portal images quickly and accurately has been developed. The approach uses a cross-correlation operator to find the optimal match between corresponding anatomic regions that have been selected by a user on pairs of portal images. The cross-correlation operator determines the translation that best registers each pair of anatomic features independently, and then the images are translated, rotated, and scaled so that the least squares difference between the coordinates of all of the paired regions is minimized. Tests using simulated images have shown that the accuracy of the algorithm is dependent on (i) the size and shape of the structures within the paired regions; (ii) the subject contrast of the anatomic features being matched; (iii) the rotational difference between the anatomic features; and, (iv) the noise in the image. Tests using contrast-detail phantom images have shown that the semiautomated registration algorithm is only slightly less accurate than human observers, but is considerably faster. The semiautomated algorithm shows great promise as a method of quickly and accurately estimating discrepancies in patient positioning when used in conjunction with an on-line portal imaging system.

Algorithms↗
PubMed1992

Novel 5-HT3 antagonists: indol-3-ylspiro(azabicycloalkane-3,5'(4'H)-oxazoles).

The synthesis and biochemical evaluation of a series of spirofused indole oxazoline 5-HT3 antagonists is described in which the oxazoline ring acts as a bioisosteric replacement for esters and amides. The effect of substitution about the indole ring has shown the steric limitations of the aromatic binding site. Incorporation of a variety of azabicyclic systems within the rigid spirofused framework has allowed the definition of a binding model which incorporates a number of known antagonists and agonists. In this model steric constraints limit substitution around the indole ring although there is some bulk tolerance at the 1- and 2-positions. The importance of constraining the basic nitrogen within an azabicyclic system is underlined by comparison with the monocyclic piperidine. The highest affinity was observed for those compounds in which the basic nitrogen occupies a bridgehead position, the most potent analogue in this group being the azabicyclic [3.3.1] system (pIC50 = 8.95), suggesting lipophilic interactions may play a role in increasing affinity. A suggested model for agonist binding is included in which the basic nitrogens are superimposed and the 5-hydroxyl group of 5-HT is superimposed on the H-bond-accepting atom of the heterocyclic linking group.

Animals↗
PubMed1991

Nucleotide sequence of cDNA encoding the coat protein of beet yellows virus.

A cDNA clone of beet yellows viral RNA expressed the viral coat protein gene in E. coli. The sequence of the 2724 nucleotide insert revealed three open reading frames, the 3' of which was shown to be the coat protein cistron. This cistron is expressed in E. coli, in spite of there being no obvious ribosome binding site upstream.

Amino Acid Sequence↗
PubMed1991

Novel 5-HT3 antagonists. Indole oxadiazoles.

The synthesis and biochemical evaluation of a series of indole oxadiazole 5-HT3 antagonists are described. The key pharmacophoric elements have been defined as a basic nitrogen, a linking group capable of H-bonding interactions, and an aromatic moiety. The steric limitations of the aromatic binding site have been determined by substitution about the indole ring. Variation of the heterocyclic linking group has shown that while two hydrogen-bonding interactions are possible, only one is essential for high affinity. The environment of the basic nitrogen has been investigated and shown to be optimal when constrained within an azabicyclic system. These results have been incorporated into a proposed binding model for the 5-HT3 antagonist binding site, in which the optimum distance between the aromatic binding site and the basic amine is 8.4-8.9 A and the steric limitations are defined by van der Waals difference mapping.

Animals↗
PubMed1989

Novel benzodiazepine receptor partial agonists: oxadiazolylimidazobenzodiazepines.

The synthesis and biochemical evaluation of a series of oxadiazole derivatives of imidazobenzodiazepines related to the benzodiazepine antagonist Ro 15-1788 (2a) are reported. Although the oxadiazole ring is seen as an isosteric replacement for the ester linkage, significant differences in structure-activity trends were observed. Specifically, oxadiazoles 9-12 invariably had increased receptor efficacy (as witnessed by measurements of the GABA shift) relative to the corresponding ester. Additionally, and in direct contrast to the classical agonists such as diazepam, affinity for the benzodiazepine receptor was enhanced by a 7- rather than 8-halo substituent. The results are discussed in terms of a six-point receptor-binding model originally based on the X-ray structure of 2a. For comparison, the crystal structures of two representative oxadiazole derivatives, 10h and 12o, having a 6-oxo and 6-phenyl group, respectively, were determined and the data incorporated into a modified binding model to account for the greater efficacy of these compounds. It is concluded that the antagonist behavior of 2a relies upon the hydrogen-bond-acceptor properties of the ester carbonyl oxygen whereas for the oxadiazole series this site is localized at the imidazole nitrogen.

Animals↗
PubMed1988

Massive schwannoma of the nose and paranasal sinuses.

Schwannomas, uncommon tumors of the nose and paranasal sinuses, are discovered late in their clinical course because of their obscure anatomic location. In this report, we have described the clinical findings in a massive nasal schwannoma (neurilemoma) that obstructed both nares, the left maxillary sinus, and the ethmoid sinuses, and protruded from the oropharynx and nose. The preoperative work-up included both computerized tomographic and magnetic resonance imaging studies.

Diagnosis, Differential↗
PubMed1988

Effect of synthetic tumoral PTH-related peptide on cAMP production and Na-dependent Pi transport.

Malignant hypercalcemia can be associated with a biochemical syndrome very similar to that encountered in primary hyperparathyroidism. The putative tumoral factor responsible for this syndrome has been isolated very recently from conditioned medium of a cultured lung squamous cell carcinoma (BEN), cDNA clones characterized, and an amino-terminal fragment synthesized. We investigated and compared the effect of this synthetic amino-terminal fragment of parathyroid hormone-related peptide [PTHrP-(1-34)], to purified PTHrP-(1-141) isolated from the same lung squamous cell carcinoma, and to bovine parathyroid hormone [bPTH-(1-34)] on adenosine 3',5'-cyclic monophosphate (cAMP) production and sodium-dependent phosphate transport (NaPiT) in opossum kidney (OK) epithelial cells. PTHrP-(1-34) and bPTH-(1-34) were equipotent in eliciting a 30-fold increase of cAMP production. NaPiT, as assessed by measuring the initial rate of Pi uptake, was inhibited in a concentration-dependent manner by either synthetic peptide. Half-maximal inhibition was observed with approximately 0.03-0.1 nmol/l of either bPTH-(1-34) or PTHrP-(1-34). At 10 nmol/l, either peptide produced an inhibition of 55 +/- 4 and 53 +/- 6%, respectively. This effect was specific for Pi, since the Na-dependent transport of glucose or alanine was not altered by either peptide. In OK cells dose-dependent stimulation of cAMP production and inhibition of NaPiT were also observed with purified native PTHrP-(1-141). In LLC-PK1 cells, which are devoid of PTH receptors, none of the peptides affected NaPiT. These results demonstrate a direct and specific effect of tumoral PTHrP on cAMP production and NaPiT in cultured renal epithelial cells in a way similar to bPTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1985

Unusual problems for the physician in managing a hospital patient who received a malicious insulin overdose.

A patient recovering normally from a biopsy and subtotal removal of a malignant brain tumor became severely hypoglycemic on the ward and died. The differential diagnosis eliminated disease as a possible cause, and medication error on the floor was also ruled out. Deliberate administration of a massive dose of insulin intravenously seemed to be the only alternative. A careful investigation supported the likelihood of a criminal act. The patient's wife came under suspicion and was subsequently arrested, charged with murder, and convicted. This sequence of events created three problems that fell outside of our normal professional training and experience as physicians. First, we were slow to suspect foul play in our search for an unusual cause. Second, the steps taken to protect the patient against further risk without denying reasonable rights to family or arousing the suspect's suspicions needed strengthening. Third, even though the occurrence of these events in a hospital allowed an unusual degree of evidence documenting the allegations to be accumulated, key parts of the evidence could not be used. The routine hospital handling of laboratory tests critical to support of the accusations was not sufficient to meet the demands of the legal system, which has its own criteria. We discuss the issues in managing these problems.

Blood Glucose↗