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L James

Publications and source records attributed to L James.

At least 37 records · Page 2Linked to original sources
PubMed1999

IL-4 enhances IL-10 gene expression in murine Th2 cells in the absence of TCR engagement.

Both IL-4 and IL-10 are regulatory cytokines produced by Th2 cells that can down-regulate cell-mediated immune responses. The studies reported here examine the influence of various cytokines in the regulation of T cell IL-10 production. The results indicate that IL-10 gene expression by TCR transgenic Th2 cells is significantly up-regulated by IL-4 in the absence of TCR signals. IL-4 enhances both IL-10 mRNA levels and secreted protein, and this effect is not related to enhanced mRNA stability. TCR-mediated IL-10 gene expression is inhibited by cyclosporin A, but IL-4-mediated IL-10 expression is not. IL-4 also enhances IL-13 mRNA levels, to a lesser extent than IL-10, but does not significantly effect the expression of other cytokine mRNAs. Furthermore, IL-4 does not significantly enhance IL-10 expression in Th1 cells. IL-2 also enhances effector cytokine production in the absence of TCR signals, but in a subset nonspecific manner, increasing both Th2 IL-4 mRNA and Th1 IFN-gamma mRNA. These data suggest that Th2 IL-4 production may contribute to the down-regulation of immune responses by directly enhancing Th2 IL-10 production. In addition, the data clearly demonstrate that exogenous cytokines can significantly influence effector cytokine production by effector T cells without the requirement for TCR signals.

Adjuvants, Immunologic↗
PubMed1999

Analogues of 1-(3,10-dibromo-8-chloro-6,11-dihydro-5H-benzo-[5,6]-cyclohepta [1,2-b]pyridin-11-yl)piperidine as inhibitors of farnesyl protein transferase.

The synthesis of several 4-pyridylacetyl N-oxide derivatives of 4-(3-bromo-6,11-dihydro-5H-benzo[5,6]-cyclohepta[1,2-b]-pyridin-11-yl)pi perazine/piperidine 3 is described. This study was aimed at identifying fomesyl protein transferase (FPT) inhibitors in these two series of tricycles containing different phenyl ring substituents. The in vitro activity profile of the initial group of compounds 7a-7g led to the synthesis of the 8-methyl-10-methoxy and 8-methyl-10-bromo analogues 7i, 13i, and 13j. The 11R(-) enantiomers of these compounds were found to exhibit potent in vitro FPT inhibition activity.

Alkyl and Aryl Transferases↗
PubMed1999

Urine drug screening.

Explore the source record for details and available documents.

Gas Chromatography-Mass Spectrometry↗
PubMed1999

Parent-daughter discussions to discourage tobacco use: feasibility and content.

Parents engaged their 6th- and 8th-grade daughters in a conversation about tobacco. The parents were guided by a pamphlet designed to encourage effective family communication about tobacco. Conversations were audiotaped for later coding. Evidence is presented that such parent-daughter conversations about tobacco use can be successfully carried out in a nonaversive manner. Overall, the conversations were perceived to have gone well, with very little conflict reported. Further, the daughters reported that the parental advice was helpful and they did not resist receiving such advice. Among the topics suggested by the pamphlet, the following were most frequently discussed: consequences of smoking as experienced by friends and relatives, difficulty of quitting, promotional tactics of tobacco companies, making rules about tobacco use, and deciding on the consequences of rules adherence or violation. Other frequently discussed topics, which were not covered in the pamphlet, may also be appropriate for parent-daughter conversations: diminished physical attractiveness and body-image issues, how to resist peer pressure, and health risks.

Adolescent↗
PubMed1998

Homozygous deletions at 3p12 in breast and lung cancer.

We have constructed a physical map of the region homozygously deleted in the U2020 cell line at 3p12, including the location of putative CpG islands. Adjacent to one of these islands, we have identified and cloned a new gene (DUTT1) and used probes from this gene to detect two other homozygous deletions occurring in lung and breast carcinomas: the smallest deletion is within the gene itself and would result in a truncated protein. The DUTT1 gene is a member of the neural cell adhesion molecule family, although its widespread expression suggests it plays a less specialized role compared to other members of the family.

Breast Neoplasms↗
PubMed1998

Inhibitors of farnesyl protein transferase. Synthesis and biological activity of amide and cyanoguanidine derivatives containing a 5,11-dihydro[1]benzthiepin, benzoxepin, and benzazepin [4,3-b]pyridine ring system.

Bioisosteric replacement of the C-6 carbon atom in piperidine I and piperazine II with S, O, and N heteroatoms is described. Amide and cyanoguanidine derivatives of these compounds were evaluated in vitro and found to be good inhibitors of farnesyl-protein transferase. An improved method of preparing the 5,11-dihydro-[1]-benzthiepin nucleus 6 was accomplished in high yield and with excellent regioselectivity using an AlCl3 melt protocol.

Alkyl and Aryl Transferases↗
PubMed1998

Synthesis of isomeric 3-piperidinyl and 3-pyrrolidinyl benzo[5,6]cyclohepta[1,2-b]pyridines: sulfonamido derivatives as inhibitors of Ras prenylation.

Blocking farnesylation of oncogenic Ras proteins is a mechanism based therapeutic approach that is of current interest for the development of antitumor agents to treat ras associated tumors. As part of a SAR study on the lead farnesyl protein transferase (FPT) inhibitor I, we report here the synthesis of novel geometric isomers II and III and the FPT inhibition activity of their N-acyl and N-sulfonamido derivatives 15-65. The N-acyl derivatives are markedly less active than the lead inhibitor I thereby demonstrating that the spatial location of the N-acyl group in I is critical for binding of the compound to FPT. In contrast to I, the N-sulfonamido-II series is a novel lead of non-sulfhydryl, nonpeptidic compounds that are dual FPT/GGPT inhibitors. In light of recent reports on the alternative prenylation of N- and K-Ras, dual FPT/GGPT inhibitors may be required to control cell proliferation in tumors containing activated Ras.

Alkyl and Aryl Transferases↗
PubMed1997

K- and N-Ras are geranylgeranylated in cells treated with farnesyl protein transferase inhibitors.

The association of mutant forms of Ras protein with a variety of human cancers has stimulated intense interest in therapies based on inhibiting oncogenic Ras signaling. Attachment of Ras proteins to the plasma membrane is required for effective Ras signaling and is initiated by the enzyme farnesyl protein transferase. We found that in the presence of potent farnesyl protein transferase inhibitors, Ras proteins in the human colon carcinoma cell line DLD-1 were alternatively prenylated by geranylgeranyl transferase-1. When H-Ras, N-Ras, K-Ras4A, and K-Ras4B were expressed individually in COS cells, H-Ras prenylation and membrane association were found to be uniquely sensitive to farnesyl transferase inhibitors; N- and K-Ras proteins incorporated the geranylgeranyl isoprene group and remained associated with the membrane fraction. The alternative prenylation of N- and K-Ras has significant implications for our understanding of the mechanism of action of farnesyl protein transferase inhibitors as anti-cancer chemotherapeutics.

Adenocarcinoma↗
PubMed1997

Characterization of Ha-ras, N-ras, Ki-Ras4A, and Ki-Ras4B as in vitro substrates for farnesyl protein transferase and geranylgeranyl protein transferase type I.

Ras proteins are small GTP-binding proteins which are critical for cell signaling and proliferation. Four Ras isoforms exist: Ha-Ras, N-Ras, Ki-Ras4A, and Ki-Ras4B. The carboxyl termini of all four isoforms are post-translationally modified by farnesyl protein transferase (FPT). Prenylation is required for oncogenic Ras to transform cells. Recently, it was reported that Ki-Ras4B is also an in vitro substrate for the related enzyme geranylgeranyl protein transferase-1 (GGPT-1) (James, G. L., Goldstein, J. L., and Brown, M. S. (1995) J. Biol. Chem. 270, 6221-6226). In the current studies, we compared the four isoforms of Ras as substrates for FPT and GGPT-1. The affinity of FPT for Ki-Ras4B (Km = 30 nM) is 10-20-fold higher than that for the other Ras isoforms. Consistent with this, when the different Ras isoforms are tested at equimolar concentrations, it requires 10-20-fold higher levels of CAAX-competitive compounds to inhibit Ki-Ras4B farnesylation. Additionally, we found that, as reported for Ki-Ras4B, N-Ras and Ki-Ras4A are also in vitro substrates for GGPT-1. Of the Ras isoforms, N-Ras is the highest affinity substrate for GGPT-1 and is similar in affinity to a standard GGPT-1 substrate terminating in leucine. However, the catalytic efficiencies of these geranylgeranylation reactions are between 15- and 140-fold lower than the corresponding farnesylation reactions, largely reflecting differences in affinity. Carboxyl-terminal peptides account for many of the properties of the Ras proteins. One interesting exception is that, unlike the full-length N-Ras protein, a carboxyl-terminal N-Ras peptide is not a GGPT-1 substrate, raising the possibility that upstream sequences in this protein may play a role in its recognition by GGPT-1. Studies with various carboxyl-terminal peptides from Ki-Ras4B suggest that both the carboxyl-terminal methionine and the upstream polylysine region are important determinants for geranylgeranylation. Furthermore, it was found that full-length Ki-Ras4B, but not other Ras isoforms, can be geranylgeranylated in vitro by FPT. These findings suggest that the different distribution of Ras isoforms and the ability of cells to alternatively process these proteins may explain in part the resistance of some cell lines to FPT inhibitors.

Alkyl and Aryl Transferases↗
PubMed1997

Generation of a contig comprising YACs and BACs within chromosome region 1p13.1.

Chromosome region 1p13 is known to show loss of heterozygosity (LOH) in a number of human tumor types, including breast. We have generated a contig comprising YACs and BACs spanning part of 1p13.1 which includes the smallest region of overlapping loss identified in our earlier studies. The contig is anchored to the genetic map by a number of microsatellite markers, and by the use of CEPH YACs. We have excluded a number of candidate genes from this region, and we have oriented the contig with respect to the centromere and a number of other genes and markers on 1p13. This resource will be valuable in mapping the target for LOH in breast and other tumors, and may also be useful for the genetic analysis of other genes or diseases known to map to this region.

Chromosome Mapping↗
PubMed1997

The effect of blood transfusion on oxygenation in premature ventilated neonates.

UNLABELLED: The effect of blood transfusion to maintain a preset packed cell volume (PCV) level in preterm ventilated infants has been investigated. Fifty infants, median gestational age 26 (range 23-33) weeks and postnatal age 4 (1-29) days, transfused a median of 15 ml/kg of blood in response to a PCV < or = 40% were retrospectively identified and their medical records reviewed to determine the change in PCV and haemoglobin resulting from the transfusions. In addition, their mean airway pressure (MAP) was noted and, as an index of oxygenation, their oxygenation index (OI), alveolar/arterial oxygen gradient (AaDO2) and arterial/alveolar (a/A) ratio calculated 12 h, 6 h and immediately prior to the transfusion and immediately post, 12, 18 and 24 h after the transfusion. The transfusion improved the PCV and haemoglobin (P < 0.0001). No significant changes in MAP or level of oxygenation were experienced in the 12 h prior to the transfusion. Post transfusion, despite no significant change in MAP, the AaDO2 OI and a/A ratios compared to immediately prior to the transfusion were significantly better at 12, 18 and 24 h. CONCLUSION: It is useful to transfuse ventilated preterm infants to maintain their PCV above a preset level.

Blood Gas Analysis↗
PubMed1997

Ras oncoprotein inhibitors: the discovery of potent, ras nucleotide exchange inhibitors and the structural determination of a drug-protein complex.

The nucleotide exchange process is one of the key activation steps regulating the ras protein. This report describes the development of potent, non-nucleotide, small organic inhibitors of the ras nucleotide exchange process. These inhibitors bind to the ras protein in a previously unidentified binding pocket, without displacing bound nucleotide. This report also describes the development and use of mass spectrometry, NMR spectroscopy and molecular modeling techniques to elucidate the structure of a drug-protein complex, and aid in designing new ras inhibitor targets.

Crystallography, X-Ray↗
PubMed1997

Antitumor 8-chlorobenzocycloheptapyridines: a new class of selective, nonpeptidic, nonsulfhydryl inhibitors of ras farnesylation.

Ras farnesylation by farnesyl protein transferase (FPT) is an intracellular event that facilitates the membrane association of the ras protein and is involved in the signal transduction process. FPT inhibition could be a novel, noncytotoxic method of treating ras dependent tumor growth. We report here three structural classes of 8-chlorobenzocycloheptapyridines as novel, nonpeptidic, nonsulfhydryl FPT inhibitors having antitumor activity in mice when dosed orally. We discuss structural and conformational aspects of these compounds in relation to biological activities as well as a comparison to the conformation of a bound tetrapeptide FPT inhibitor.

Animals↗
PubMed1997

Detection and structural characterization of ras oncoprotein-inhibitors complexes by electrospray mass spectrometry.

MS based methodology employing electrospray ionization (ESI) is described for the detection of ternary complexes in which SCH 54292 or SCH 54341 and GDP are noncovalently bound to oncogenic ras protein. The observed molecular weights of 19,816 and 19,570 Da confirmed the presence of noncovalent complexes of ras-GDP-SCH 54292 and ras-GDP-SCH 54341, respectively. We have also performed selective chemical modification of lysine residues of the ras protein complex followed by enzymatic digestion and on-line LC-ESI MS peptide mapping to determine protein-drug binding topography. There was a good correlation between nucleotide exchange inhibition as determined by the enzyme assay and evidence of complex formation as determined by MS.

Amino Acid Sequence↗
PubMed1997

Identification of genetic changes associated with drug resistance by reverse in situ hybridization.

The molecular cytogenetic techniques of comparative genomic hybridization (CGH) and reverse in situ hybridization (REVISH) allow the entire genomes of tumours to be screened for genetic changes without the requirement for specific probes or markers. In order to define the ability of REVISH to detect and map regions of amplification associated with drug resistance, we investigated a panel of cell lines selected for resistance to doxorubicin and intrinsic sensitivity to topoisomerase II-inhibitory drugs. We have defined a modified REVISH protocol, which involves double hybridizations with genomic DNA from the test cell lines and chromosome-specific whole chromosome paints to identify the chromosomes to which the amplicons localize. Sites of amplification are then mapped by fractional length measurements (Flpter), using published genome databases. Our findings show that amplification of the topoisomerase II alpha gene is readily detected and mapped, as is amplification of the MDR and MRP loci. Interestingly, REVISH detected a new amplicon in the doxorubicin-resistant lung cancer cell line, GLC4-ADR, which mapped to chromosome 1q. REVISH is therefore ideally suited to characterize genetic changes specific for drug resistance within a background of genetic anomalies associated with tumour progression.

Chromosome Mapping↗
PubMed1997

Impact of the in-house trauma surgeon on initial patient care, outcome, and cost.

BACKGROUND: The purpose of this study is to evaluate the effect of having attending trauma surgeons with added qualifications in surgical critical care present for the initial resuscitation at a regional trauma center. METHODS: This study is a retrospective review of patients admitted between August of 1994 and December of 1995 from our trauma registry. The patients were categorized by the call preference of the admitting physician as in-house (IH) or call-back from home (CB), day of admission (weekend vs. weekday), time of admission (AM VS. PM), and a value of the injury severity scale < or = 15 or > 15. Demographics, admission vital signs, Injury Severity Scale, Glasgow Coma Score, and elapsed time to diagnostic, therapeutic, and/or operative interventions were studied. The effect on intensive care unit length of stay, mortality, and hospital cost for resuscitation were also studied. RESULTS: The study population consisted of 1,043 patients. The IH and CB groups each included two attending surgeons. IH significantly reduced the average time to completion of diagnostic peritoneal lavage (22 vs. 34 minutes; p < 0.05), therapeutic intervention (21 vs 38 minutes; p < 0.05), and transport to the operating room (206 vs. 312 minutes; p < 0.05) during the AM compared with CB. There was no difference in these times for the PM admissions. There was no significant difference in intensive care unit length of stay. Among patients with severe head and thoracoabdominal injury (Abbreviated Injury Score > 4 and 3, respectively) there was no difference in mortality. Analysis of cost for emergency room resuscitation in severely injured patients (Injury Severity Score > or = 15), seen during weekdays, was significantly less when evaluated by IH (IH = $5,097 vs. CB = $6,779; p < 0.05). CONCLUSIONS: During the initial resuscitation of patients with severely injured during the weekdays, IH significantly reduced the cost, and elapsed time to diagnostic testing, therapeutic intervention, and to the operating room, respectively. IH reduced fatalities compared with CB.

Adult↗
PubMed1997

The needs of parents of pediatric oncology patients during the palliative care phase.

The death of a child is considered one of the greatest stresses a parent can experience. It has been suggested that death from childhood malignancies is more stressful for parents than death due to other chronic diseases. The purpose of this qualitative study is to identify parents' perceptions of their needs while their child was dying of cancer. Twelve parents of eight children, who died of various types of cancer 1 to 3 years ago, were interviewed by the primary investigator. These children died either in hospital or at home. Interviews were tape recorded, transcribed and analyzed by the investigators. Three needs were identified: (1) The need to have the child recognized as special while retaining as much normality within the child's and family's lives as possible; (2) The need for caring and connectedness with health care professionals; and (3) The need to retain responsibility of parenting their dying child. Findings suggest that parental needs are similar regardless of where the death occurred. Implications for nursing practice and areas for further research were identified.

Adolescent↗