bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scheduling Flexible Servers with Convex Delay Costs: Heavy-Traffic Optimality of the Generalized cμ-Rule
Authors: Mandelbaum Avishai , Stolyar Alexander L. 
Published: December 2004

We consider a queueing system with multitype customers and flexible (multiskilled) servers that work in parallel. If Qi is the queue length of type i customers, this queue incurs cost at the rate of Ci(Qi), where Ci(·) is increasing and convex. We analyze the system in heavy traffic (Harrison and Lopez 1999) and show that a very simple generalized cμ-rule (Van Mieghem 1995) minimizes both instantaneous and cumulative queueing costs, asymptotically, over essentially all scheduling disciplines, preemptive or non-preemptive. This rule aims at myopically maximizing the rate of decrease of the instantaneous cost at all times, which translates into the following: when becoming free, server j chooses for service a type i customer such that i ε arg maxi Cμi(Qi)μij, where μij is the average service rate of type i customers by server j. An analogous version of the generalized cμ-rule asymptotically minimizes delay costs. To this end, let the cost incurred by a type i customer be an increasing convex function Ci(D) of its sojourn time D. Then, server j always chooses for service a customer for which the value of C′i(D) μij is maximal, where D and i are the customer's sojourn time and type, respectively.
Effect of Blood Collection Tubes on Total Triiodothyronine and Other Laboratory Assays
Authors: Bowen Raffick AR , Chan Yung , Cohen Joshua , Rehak Nadja N , Hortin Glen L , Csako Gyorgy , Remaley Alan T 
Published: December 2004

Abstract
Background: Increased total triiodothyronine (TT3) assay results in apparently euthyroid patients triggered an investigation of the effect of blood collection tubes on serum TT3 and other laboratory assays.
Methods: We examined potential assay interference for three types of tubes: plastic Greiner Bio-One™ Vacuette™; glass Becton Dickinson (BD) Vacutainer™; and plastic BD Vacutainer SST™ tubes. Serum samples from apparently healthy volunteers (age range, 30–60 years; 15 males and 34 females) were collected in different tube types and analyzed in 17 immunoassays (n = 49), 30 clinical chemistry tests (n = 20), and 33 immunology assays (n = 15). Tube effects were also examined by adding pooled serum to different tube types.
Results: TT3 values, when measured by the IMMULITE™ 2000 but not the AxSYM™ analyzer, were significantly higher (P &lt;0.0001) for SST (2.81 nmol/L) than either glass (2.15 nmol/L) or Vacuette (2.24 nmol/L) tubes. The effect was large enough to substantially shift the distribution of patient values, increasing the percentage of values above the reference interval from 11.3% to 35.8%. The degree of interference from SST tubes on TT3 differed among various tube lots and could be attributed to a tube additive shared by other plastic tubes. Results from several other tests statistically differed among tube types, but differences were not considered to be clinically significant.
Conclusions: Assay interferences from blood collection tubes represent challenges to clinical laboratories because they are not detected by the usual quality-control or proficiency testing programs. Laboratories can, however, address this problem by monitoring distribution of patients’ results.
Genetic and epigenetic regulation of human breast cancer progression and metastasis
Authors: Welch D R , Wei L L 
Published: December 2004

Breast cancer is the most common malignancy and a major cause of cancer-related deaths among women in the United States and Western Europe (American Cancer Society 1998, Wingo et al. 1998). Most women succumb to breast cancer if their tumors metastasize but cures are more likely if the cancers remain localized (Harris et al. 1992a,b,c, Walker et al. 1997). Thus, a greater understanding of the metastatic process in human breast cancer should translate into substantial improvements in therapeutic outcome for breast cancer patients. Towards that end, we will review and summarize the literature about, and begin to develop a working model for, the genetics of human breast cancer metastasis. There have been great strides in recent years with regard to our overall understanding of metastasis. Yet our apparently straightforward objective - to define cause-effect relationships for genes in breast cancer - was difficult because of four issues. First, many reports fail to distinguish between oncogenesis and progression or invasion and metastasis when reporting data. Secondly, there is a failure, by some, to recognize that breast cancer is not a single disease, but a collection of diseases. This is particularly apparent in the genetics literature. Thirdly, it is difficult to evaluate the relative importance of correlative data, particularly as it relates to mechanistic control of steps in the metastatic cascade. Fourthly, there is a tremendous noise-to-signal ratio for genetics of late-stage, metastatic breast cancers resulting from genotypic instability, phenotypic drift and tumor heterogeneity.
Acknowledgements
We are particularly indebted to Dr Bernard E Weissman from the University of North Carolina at Chapel Hill. Much of the published work described here was done in conjunction with his laboratory. We also appreciate the efforts of Andrea Manni, P G Satyaswaroop, Michael Verderame, and Steven Goldberg for critical reading and helpful comments and suggestions. We also appreciate the support of grants from the US Army Medical Research and Material Command (DAMD17-96-6152 to D R W); the National Foundation for Cancer
Research (to D R W and L L W); PHS grant CA62168 (to D R W), the Latham Fund (L L W) and the Jake Gittlen Memorial Golf Tournament (D R W).
Mistyping of the human angiotensin-converting enzyme gene polymorphism: frequency, causes and possible methods to avoid errors in typing
Authors: Ueda S , Heeley R P , Lees K. R , Elliott H L , Connell J M C 
Published: December 2004

ABSTRACT
A polymorphism of the gene encoding the human angiotensin I-converting enzyme (ACE), which is defined by an insertion/deletion polymorphism in intron 16, has been identified as a candidate genetic locus in the development of cardiovascular and renal disease.
We have demonstrated that the accuracy of ACE genotyping is critically dependent on the strategy of the PCR used in typing. Of 1238 individuals genotyped by a standard method, 335 were typed as DD, 645 as DI and 258 as II. However, when DD individuals were retyped using modified methods (including either 5% dimethyl sulphoxide, or a 'hot start') 35 of the original 335 samples (10·5%) were retyped as DI.
In approximately half of these mistyped samples, PCR amplification was assessed as inefficient by the absence of a third faint heteroduplex band in a control ID sample: when the assay was repeated without any modifications, the mistyped samples were correctly genotyped. In the remainder, mistyping persisted. In these cases, the use of a third 'nested' PCR primer specific for the I allele was required for successful genotyping, providing a more reliable strategy without the need for further modification to the PCR technique. Our results suggest that the triple primer approach is the method of choice for accurate ACE genotyping.
Expression of growth factor ligand and receptor genes in rat cancellous bone trabeculae and marrow
Authors: Watson P H , Watson A J , Hodsman A B 
Published: December 2004

ABSTRACT
The technique of reverse transcription-PCR for mRNA phenotyping was applied to total RNA isolated from the two compartments of cancellous bone, namely trabecular bone and hematopoitic tissue or marrow. The pattern of gene expression for ten different growth factor ligands and five growth factor receptors was examined in total RNA isolated from the two compartments of cancellous bone of the female rat distal femur. Our results show that transcripts encoding IGF-I, IGF-II, transforming growth factor-β1 (TGF-β1), TGF-α, basic fibroblast growth factor, platelet-derived growth factor A and osteocalcin are detectable in samples from both trabeculae and marrow. Expression of epidermal growth factor (EGF) was confined to samples from trabeculae while nerve growth factor expression was only detected in marrow. Transcripts encoding insulin were not detected in any of the bone-derived samples in this study. Samples from cancellous bone trabeculae and marrow both showed evidence of expression of the genes encoding receptors for IGF-I, parathyroid hormone (PTH)/PTH-related protein and insulin. Neither compartment of cancellous bone contained transcripts encoding the receptor for IGF-II. Transcripts encoding the EGF receptor were detected in samples from cancellous bone marrow and not trabeculae as has been previously reported. These patterns of growth factor ligand and receptor gene expression suggest that it is likely that both autocrine and paracrine regulatory circuits are established in cancellous bone. This study also demonstrated the feasibility of assessing the expression of multiple genes from the small samples of total RNA obtained from separated tissues of cancellous bone. This is the first time that growth factor gene expression has been examined in separated trabeculae and marrow from cancellous bone and this approach will allow a more detailed analysis of molecular events in cancellous bone as opposed to whole bone or extracts of isolated and cultured bone cells.
Development of cytochrome P450 17α-hydroxylase (P450c17) mRNA and enzyme activity in neonatal ovaries of normal and hypogonadal (hpg) mice
Authors: Gray S A , Mannan M A , O'Shaughnessy P J 
Published: December 2004

ABSTRACT
The cytochrome P450 enzyme 17α-hydroxylase (P450c17) is required for androgen synthesis and therefore regulates substrate supply for aromatization. In this study, changes in P450c17 activity and mRNA levels were measured during ovarian development in the normal mouse and in the hypogonadal (hpg) mouse which lacks circulating gonadotrophins. At birth, low levels of P450c17 activity and mRNA were detectable in normal ovaries. This basal level of expression did not change until after day 10 at which time both enzyme activity and mRNA levels increased by six- to eightfold. In the hpg mouse, levels of P450c17 mRNA were normal at birth but did not change significantly during subsequent development and were significantly less than normal by day 15. Results show that there is a low level of gonadotrophin-independent expression of P450c17 in the ovary at birth and that gonadotrophins are required for the subsequent increase in expression between days 10 and 15. In the ovary, P450c17 is expressed solely in the thecal/interstitial compartment and interstitial cells arise in the mouse ovary around day 11. Changes in P450c17 are likely, therefore, to be related to gonadotrophin-dependent development of the interstitial tissue in the mouse. Treatment of adult hpg mice with LH and FSH showed that both gonadotrophins can act to increase P450c17 activity. Since FSH acts only on the granulosa cell compartment of the ovary it is likely that FSH acts through a paracrine mechanism to regulate thecal/interstitial cell activity.
Multiple signal transduction pathways regulate clusterin (gp 80) gene expression in MDCK cells
Authors: Gutacker C , Flach R , Diel P , Klock G , Koch-Brandt C 
Published: December 2004

ABSTRACT
Clusterin (gp 80, apolipoprotein J, TRPM-2) is a widely expressed multifunctional glycoprotein. Its demonstrated and proposed functions include the transport of lipids and membrane fragments, the inhibition of the cytolytic action of the terminal complement complex and the modulation of cell—cell interactions. The expression of the gene is enhanced during tissue injury and remodelling and by hormone-withdrawal-induced apoptosis of prostate and mammary cells. We show here that, in the kidney-derived epithelial cell line MDCK, clusterin mRNA is repressed by glucocorticoids and by progesterone. Treatment with epidermal growth factor also represses clusterin gene expression in MDCK cells. Incubation with 12-O-tetradecanoyl-phorbol-13-acetate, which activates protein kinase C (PKC), induces clusterin mRNA, while chelerythrine, an inhibitor of PKC, represses clusterin gene expression, suggesting that the clusterin gene responds to signalling pathways involving PKC. These results open up the possibility of studying the complex regulation of the clusterin gene by multiple signal transduction pathways within a single cell type, and most importantly, of characterizing interactions between the individual signal transduction cascades.
Cloning and sequence analysis of the human gene encoding steroidogenic factor 1
Authors: Wong M , Ramayya M S , Chrousos G P , Driggers P H , Parker K L 
Published: December 2004

ABSTRACT
The orphan nuclear receptor steroidogenic factor 1 (SF-1) plays key roles in endocrine development and function. Initially identified as a positive regulator of the cytochrome P450 steroid hydroxylases, analyses of knockout mice deficient in SF-1 revealed that SF-1 is essential for adrenal and gonadal development, pituitary gonadotropin expression and formation of the ventromedial hypothalamic nucleus. Although more limited in scope, analyses of SF-1 in humans similarly have suggested that SF-1 is important for differentiated function in adrenocortical and gonadotrope adenomas. In the hope of extending our understanding of SF-1 function by identifying possible roles of SF-1 in clinical endocrine disorders, we isolated the FTZ-F1 gene encoding human SF-1 and mapped it to chromosome 9q33. In this report, we characterize the sequence and structural organization of the human cDNA and gene encoding SF-1, providing new insights into comparative aspects of SF-1 structure that will facilitate efforts to study the role of this transcription factor in human endocrine disorders.
High-level expression of recombinant immunoreactive thyroid peroxidase in the High Five insect cell line
Authors: Jones F Grennan , Wolstenholme A , Fowler S , Smith S , Ziemnicka K , Bradbury J , Furmaniak J , Smith B Rees 
Published: December 2004

ABSTRACT
Expression of a major thyroid autoantigen, thyroid peroxidase (TPO) was studied using the baculovirus-insect cell expression system. Human TPO cDNA modified so as to code for the extracellular fragment of the protein was placed under the control of the strong polyhedrin promoter in baculovirus transfer vector pBlueBacIII and cotransfected with linearized AcMNPV viral DNA. Expression in two insect cell lines Spodoptera frugiperda (Sf9) and Tricoplusia ni (High Five) was investigated and levels of recombinant TPO (rTPO) monitored by RIA and SDS-PAGE followed by Western blotting. Both insect cell lines expressed rTPO, but higher levels (30 mg/l culture medium) were obtained with High Five cells. Culture medium rTPO was purified and its glycosylation and immunoreactivity analysed. Lectin-affinity blotting and treatment with glycosidases indicated that both high mannose and complex-type sugar residues were associated with the recombinant protein. Studies with an ELISA based on biotin-labelled rTPO and an immunoprecipitation assay based on 125I-labelled rTPO indicated that the rTPO and native TPO showed similar reactivity to TPO autoantibodies (r=0·96, P<0·001, n=50 and r=0·99, P<0·001, n=80 respectively).
In addition, rTPO expressed in High Five cells showed enzyme activity comparable with that of native TPO when the heme biosynthesis precursor δ-aminolevulinic acid was included in the culture medium.
Overall, our studies indicate that the High Five insect cell line provides a useful system for the expression of relatively high levels of rTPO which should be suitable for structural analysis of TPO and TPO—TPO autoantibody complexes.
Mutations of Arg68 of the human chorionic gonadotrophin β subunit lead to reduced secretion
Authors: Shen L , Xia H , Bhowmick N , Narayan P , Puett D 
Published: December 2004

ABSTRACT
The Arg68-Leu69 sequence is invariant in the β subunits of chorionic gonadotrophin and luteinizing hormone from a variety of species. Using site-directed mutagenesis of the human chorionic gonadotrophin (hCG)-β cDNA, several replacements of Arg68, an Ala replacement of Leu69, and a multiple replacement with Ala-Ala-Ala-Ala of the tetrapeptide sequence, Arg68-Leu69-Pro70-Gly71, were prepared and characterized. The wild-type and mutant cDNAs were subcloned into a pRSV expression vector and transiently transfected into CHO cells containing a stably integrated gene for bovine a. Concentrations of secreted wild-type and mutant hCG-β subunit and holoprotein were determined using radioimmunoassays; potencies, i.e. the ratio of biologic to immunologic activity, of several of the mutant heterodimers were measured in vitro via gonadotrophin-mediated steroidogenesis in transformed murine Leydig cells (MA-10). The Leu69→Ala mutant formed a mutant holoprotein that was essentially equipotent with wild-type hormone in the steroidogenesis assay. The Arg68 replacements with Lys, Ala, and Leu were poorly secreted by the cells, e.g. <10% that of wild-type hCG; however, sufficient quantities of mutant holoproteins containing Lys68 and Ala68 were obtained for biological assays, and both exhibited greater apparent potencies than wild-type hormone. Likewise, a mutant holoprotein containing the Arg68-Leu69-Pro70-Gly71→Ala-Ala-Ala-Ala multiple replacement was apparently more potent than wild-type hormone, but it too was secreted at lower levels than wild-type. These results establish that replacements of Arg68 in hCG-β diminish secretion, but the small amount of holoprotein that is formed and secreted appears to be of somewhat greater potency than wild-type hormone.
Isolation and characterization of the cDNA encoding the tilapia (Oreochromis niloticus) cytochrome P450 aromatase (P450arom): changes in P450arom mRNA, protein and enzyme activity in ovarian follicles during oogenesis
Authors: Chang X T , Kobayashi T , Kajiura H , Nakamura M , Nagahama Y 
Published: December 2004

ABSTRACT
A cDNA clone encoding the complete tilapia (a teleost fish, Oreochromis niloticus) cytochrome P450 aromatase (P450arom) was isolated from an ovarian follicle cDNA library. The deduced amino acid sequence (522 amino acid residues) had 72·2% and 59·5% homology with rainbow trout and catfish P450arom respectively, and about 50% homology with mammalian and avian P450arom. Expression of this cDNA in COS-7 cells produced a protein that converted exogenous testosterone to estrogens. Northern blots using a tilapia P450arom cDNA fragment and Western blots using an antiserum against a tilapia P450arom polypeptide fragment revealed a single P450arom mRNA (2·6 kb) and a single protein (59 kDa) in tilapia ovarian tissue respectively. These analyses also revealed that the levels of both P450arom mRNA and protein were low in early vitellogenic follicles, increased in midvitellogenic follicles, and declined to non-detectable levels in post-vitellogenic follicles. Changes in the ability of follicles to convert exogenous testosterone to estrogens (aromatase activity) were similar to those of P450arom mRNA and protein. These observations indicated that the capacity of tilapia ovarian follicles to synthesize estradiol-17β is closely related to the contents of P450arom mRNA and protein within them.
Angiotensin II receptors in the gill of sea water- and freshwater-adapted eel
Authors: Marsigliante S , Muscella A , Vinson G P , Storelli C 
Published: December 2004

ABSTRACT
Immunocytochemistry of paraffin-embedded and cryostat sections of eel (Anguilla anguilla) gill showed that angiotensin II receptors (Ang II-R) were present in chloride cells, uniformly distributed in the cytoplasm and on surface membranes. Computerised image analysis of these preparations showed that gills from sea water (SW)-adapted animals had a significantly (3-fold) higher Ang II-R concentration compared with freshwater (FW)-adapted eel gills. Isoelectric focusing gel electrophoresis revealed two Ang II-R isoforms with pI 6·5 and 6·6 that were differentially modulated by environmental salinity: they were equally abundant in SW while in FW the pI 6·6/pI 6·5 ratio was 1·66.
Using catalytic cytochemistry with image analysis, gill chloride cell membrane Na+/K+ATPase activity was shown to increase 4-fold in response to SW adaptation. Additionally, perfusion of gills for 30 min with 0·1, 10 or with 100 nM Ang II provoked a dose-dependent increment in Na+/K+ATPase activity in FW, and a biphasic response in SW gills in which activity was significantly increased at low Ang II concentrations but was reduced to basal values at 100 nM.
The data suggest that adaptation to sea water significantly increases Ang II-R concentration in the chloride cell and, together with the effects of Ang II on Na+/K+ATPase activity, suggest a role for this hormone in gill NaCl retention. The different responses of Na+/K+ATPase to Ang II stimulation in FW and SW may be attributed to the presence of two receptor subtypes that are differently modulated by salinity and that have opposing effects on Na+/K+ATPase.
Cloning and characterization of a human leptin receptor using a biologically active leptin immunoadhesin
Authors: Luoh S-M , Di Marco F , Levin N , Armanini M , Xie M-H , Nelson C , Bennett G L , Williams M , Spencer S A , Gurney A , de Sauvage F J 
Published: December 2004

ABSTRACT
Leptin, the product of the ob gene, is a hormone secreted by fat cells which is primarily involved in the regulation of body weight. We have generated a leptin immunoadhesin (leptin-IgG) which was more potent than leptin alone at reducing body weight and food intake when injected into ob/ob mice. This molecule was used to identify high affinity binding sites on human embryonic 293 kidney cells and subsequently to isolate a cDNA encoding the leptin receptor from this cell line by expression cloning. This receptor corresponds to the short form of the recently isolated leptin receptor. Analysis of the expression pattern of the two forms of receptor by Northern blot, in situ hybridization and quantitative PCR showed that the receptor is expressed in most tissues but that the long form is prevalent in the hypothalamus.