Biomedical subjects

T Connolly

Publications and source records attributed to T Connolly.

At least 19 recordsLinked to original sources

PubMed2003

Identification of genes regulated during osteoblastic differentiation by genome-wide expression analysis of mouse calvaria primary osteoblasts in vitro.

Although several independent studies of gene expression patterns during osteoblast differentiation in cultures from calvaria and other in vitro models have been reported, only a small portion of the mRNAs expressed in osteoblasts have been characterized. We have previously analyzed the behavior of several known markers in osteoblasts, using Affymetrix GeneChip murine probe arrays (27,000 genes). In the present study we report larger groups of transcripts displaying significant expression modulation during the culture of osteoblasts isolated from mice calvaria. The expression profiles of 601 such regulated genes, classified in distinct functional families, are presented and analyzed here. Although some of these genes have previously been shown to play important roles in bone biology, the large majority of them have never been demonstrated to be regulated during osteoblast differentiation. Despite the fact that the precise involvement of these genes in osteoblast differentiation and function needs to be evaluated, the data presented herein will aid in the identification of genes that play a significant role in osteoblasts. This will provide a better understanding of the regulation of osteoblast differentiation and maturation.

Animals↗

PubMed2002

Behavior of osteoblast, adipocyte, and myoblast markers in genome-wide expression analysis of mouse calvaria primary osteoblasts in vitro.

Several genes, such as alkaline phosphatase, osteocalcin, and Cbfa1/Osf2, are known to be regulated during osteoblastic differentiation and are commonly used as "osteoblast markers" for in vitro or in vivo studies. The number of these genes is very limited, however, and it is of major interest to identify new genes that are activated or repressed during the process of osteoblast differentiation and bone formation as well as to extend the available information on gene families relevant to this particular differentiation pathway. To identify such genes, we have implemented a genome-wide analysis by determining changes in expression levels of 27,000 genes during in vitro differentiation of primary osteoblasts isolated from mouse calvaria. This study focuses on the description of the analytical and filtering process applied; on the transcriptional analysis of well-established "bone," "adipocyte," and "muscle" pathway markers; and on a description of the regulation profiles for genes recently described in the Skeletal Gene Database. We also demonstrate that new array technologies constitute reliable and powerful tools to monitor the transcription of genes involved in osteoblastic differentiation, allowing a more integrated vision of the biological pathways regulated during osteoblast commitment, differentiation, and function.

Adipocytes↗

PubMed2002

Accuracy of the TDx-FLM assay of amniotic fluid: a comparison of vaginal pool samples with amniocentesis.

OBJECTIVE: The purpose of this study was to evaluate the use of the TDx-FLM fluorescence polarization assay on vaginal pool fluid in patients with preterm premature rupture of membranes (PPROM). METHODS: A prospective matched-pairs study was performed at a tertiary care center. For each patient enrolled, amniotic fluid samples were obtained by sterile speculum examination and by amniocentesis within 12 h of each other. Inclusion criteria were the presence of PPROM and a gestational age of 30-36 weeks. The samples were analyzed separately using the TDx-FLM assay in the same laboratory. The results were compared using a paired Student t test. RESULTS: A total of 16 patients received both amniocentesis and vaginal collection of amniotic fluid. The mean gestational age at amniocentesis was 33.3 weeks (SD 1.9). In every case, the vaginal pool TDx-FLM result was lower than the amniocentesis result. The mean difference in the assays between the two fluid sources was 35% (range 17-63%, p < 0.001). Amniocentesis suggested a mature result in 12 cases (75%), an indeterminate result in two cases (12.5%), and an immature result in two cases (12.5%). Vaginal pool fluid suggested a mature result in four cases (25%), an indeterminate result in nine cases (56%), and an immature result in three cases (19%). Using the cut-off values validated for amniocentesis specimens as a standard for comparison, vaginal pool TDx-FLM assay had 42% sensitivity, 100% specificity, 100% positive predictive value and 36% negative predictive value for predicting lung maturity. CONCLUSIONS: The TDx-FLM assay on vaginal pool samples of amniotic fluid yielded results that were significantly different from those of amniocentesis samples. At this point, the assay is only clinically useful for vaginal pool samples when a mature result is obtained.

Adult↗

PubMed2001

The genetic structures of a range of Douglas-fir provenance collections after planting in different European countries, assessed with two biochemical marker systems.

Genetic diversities of Douglas-fir provenance trials planted on several European sites were compared using both isozyme and terpene markers. A principal coordinate analysis based on similarity coefficients calculated from isozyme data indicated that, with the exception of two populations, differences between populations were small. There were no consistent trends in the variation in allele frequencies between populations. Most populations contained an excess of homozygotes, perhaps due to high selection pressure. Terpene composition was analysed in two resin systems, and showed a decreasing level of population diversity by planting site in the order: Spain-France-England-Scotland-Italy. Thus isozymes, which are generally considered to be neutral markers, indicated a modest degree of genetic drift due to sampling effects, while terpenes showed that some reduction in genetic diversity had occurred due to local selective pressures.

Journal Article↗

PubMed2000

Regret and Responsibility: A Reply to Zeelenberg et al. (1998).

M. Zeelenberg, W. W. van Dijk, and A. S. R. Manstead (1998, Organizational Behavior and Human Decision Processes, 74, 254-272) recently reported an altered replication of our earlier study (T. Connolly, L. D. Ordóñez, & R. Coughlan, 1997, Organizational Behavior and Human Decision Processes, 70, 73-85) concerning the effects of decision agency on regret and outcome evaluation. Our earlier study had found no such effect, but Zeelenberg et al. did. In two new experiments, we have largely confirmed Zeelenberg et al.'s result but have shown that, contrary to most theory, regret (a) can appear even in the absence of decision agency, (b) can be unrelated to outcome evaluations, and (c) may be more influenced by the experience of gains or losses from the status quo than by any decisional responsibility for those changes. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

Synergistic anti-tumor activity of a novel immunomodulator, BCH-1393, in combination with cyclophosphamide.

N,N-dimethylaminopurine pentoxycarbonyl D-arginine (BCH-1393) is a novel low molecular weight synthetic immunomodulator that has been shown to significantly stimulate cytotoxic T-lymphocyte responses both in vitro and in vivo (Zacharie B, Gagnon L, Attardo G, Connolly TP, St-Denis Y, Penney CL. Synthesis and activity of 6-substituted purine linker amine immunostimulants. J. Med. Chem. 1997;40:2883-94). Prompted by this evidence, we extended evaluation of BCH-1393 for anticancer activity in syngeneic mouse experimental tumor models. Consistent with previous findings, in vitro assessment of BCH-1393 activity demonstrated a significant increase in the CTL responses in the range of 10(-9)-10(-5) M. Treatment of mice with four consecutive daily intraperitoneal injections at 25 and 50 mg/kg resulted in a significant increase of the relative percentage of blood CD4+, CD8+, NK and monocyte subsets without any evidence of toxicity. In vivo anti-tumor activity of BCH-1393 was evaluated, either alone or in combination with subtherapeutic doses of cyclophosphamide (Cy), against weakly immunogenic mouse breast carcinoma DA-3 and strongly immunogenic colon adenocarcinoma MC38. Daily intraperitoneal injection of BCH-1393 at 50 mg/kg alone was well tolerated but produced a relatively weak anti-tumor effect in both tumor models. However, a significant inhibition of tumor outgrowth and suppression of established tumor growth was observed when BCH-1393 was administered in combination with subtherapeutic doses of Cy. Combination treatment of 50 mg/kg BCH-1393 with 100 mg/kg Cy (given as single intravenous bolus injection) starting 2 days prior to DA-3 tumor cell inoculation prevented tumor outgrowth in 70-80% of treated mice. In the remaining 20-30% of mice that had developed tumors, a nearly complete (90%) tumor growth inhibition was observed at days 22-24 post tumor implant. In the MC38 tumor model, combination treatment of established tumors with BCH-1393 and Cy (CTX) at 50 mg/kg resulted in a significant delay in tumor growth compared to CTX treatment alone. The observed concomitant anti-tumor activity of BCH-1393 with cyclophosphamide warrants further investigation of this immunomodulator as an adjunctive treatment of cancer.

Adjuvants, Immunologic↗

PubMed2000

Tobacco cessation skills certification in Arizona: application of a state wide, community based model for diffusion of evidence based practice guidelines.

OBJECTIVE: To describe the development and preliminary results from a community based certification model for training in tobacco cessation skills in Arizona. DESIGN: A programme evaluation using both quantitative pre-post measures and qualitative methods. SETTING: Arizona's comprehensive tobacco control programme of state funded, community based local projects and their community partners providing tobacco treatment services for geographically, socioeconomically, and ethnically diverse communities. INTERVENTION: A three tiered model of skills based training emphasising Agency for Health Care Policy and Research guidelines, and utilising a training of trainers approach to build community capacity. Certification roles addressed basic tobacco cessation skills, tobacco cessation specialist, and tobacco treatment services manager. PARTICIPANTS: Initial target audience was community based local project personnel and their community partners, with later adoption by community organisations unaffiliated with local projects, and the general public. MAIN EVALUATION MEASURES: Process measures: participant satisfaction, knowledge, skills, and self-efficacy. OUTCOME: participant demographics, community organisations represented, post-training, cessation related activities. RESULTS: During the model's implementation year, 1075 participants attended certification training, 947 participants received basic skills certificates and 82 received specialist certificates. Pre, post, and three month measures of self efficacy showed significant and durable increases. Analysis of participant characteristics demonstrated broad community representation. At post-training follow up, 80.9% of basic skills trainees had performed at least one brief intervention and 74.8% had made a referral to intensive services. Among cessation specialists, 48.8% were delivering intensive services and 69.5% were teaching basic skills classes. CONCLUSIONS: Initial experience with Arizona's state wide, community based model for certification of tobacco cessation skills training suggests this model may be a promising method for broad, population based diffusion of evidence based tobacco cessation guidelines.

Humans↗

PubMed1999

Impact of physicians' perceptions of malpractice and adaptive changes on intention to cease obstetrical practice.

Physicians who provide obstetrical care in rural areas face exposure to liability action and confront a critical decision--whether to continue to offer these services. This paper draws upon social-psychological and decision theories to investigate this decision. Ninety-four percent of all obstetricians and family and general physicians practicing in the 12 nonmetropolitan counties of one state responded to a mail survey that asked about their intention to continue or discontinue obstetrical practice, two dimensions of subjective risk (perceived likelihood of threats in the malpractice environment and perceived magnitude of negative consequences from being sued), and adaptive changes to protect against malpractice. The results suggest that (a) perceived extent of negative consequences (but not perceived likelihood of malpractice threats) drives intention to leave obstetrics, (b) the professional and reputational impacts of a suit--not the dollar amount of award or settlement--predicts intention to stop practicing obstetrics, and (c) physicians planning to continue providing obstetrical care in the future have made recent practice changes that may further exacerbate access problems.

Adult↗

PubMed1998

p21(cip1) rescues human mesenchymal stem cells from apoptosis induced by low-density culture.

Mammalian cells are programmed to undergo programmed cell death in response to a variety of conditions. We demonstrate that human mesenchymal stem cells (hMSCs) undergo programmed cell death upon seeding at low density. Under these conditions, we observed an increased proportion of cells in S-phase and a decreased proportion of cells in G1-phase. This indicated that a change in control of G1-S-phase transition in response to low-density seeding had occurred and, therefore, we measured the level of cyclin-dependent kinase inhibitory proteins governing this transition. Human MSCs cultured at low density exhibited lowered levels of both the p21 and p27 cyclin-dependent kinase inhibitors, and these protein levels appear to be regulated at a post-transcriptional level. Conversely, overexpression of the p21 cell cycle-dependent kinase inhibitor but not that of p27 protected hMSCs from programmed cell death upon culture at low density. Furthermore, p21 and p27 are expressed differentially during endochondrial bone development. The loss of p21 in hypertrophic chondrocytes correlates with the onset of apoptosis during endochondrial ossification. We suggest that p21 and p27 play a central role in skeletal development.

Apoptosis↗

PubMed1997

Reduced folate carrier gene (RFC1) expression and anti-folate resistance in transfected and non-selected cell lines.

Methotrexate transport deficiency due to decreased reduced folate carrier (RFC) activity has been observed in several cell lines selected for resistance to methotrexate (MTX). Since MTX resistance is multifactorial, however, it is difficult to quantify the relative importance of changes in RFC activity in selected cell lines and even more so to determine the relative contribution of naturally occurring RFC activity in the MTX sensitivity of non-selected cell lines. We examined the role of RFC in MTX resistance by studying a transport-deficient cell line transfected with the gene for human RFC, RFC1, and by correlating relative RFC1 expression with MTX and trimetrexate (TMTX) growth inhibition (GI50) in a panel of cell lines used in the NCI Anticancer Drug Screen. Clones of transport-deficient, MTX-resistant ZR-75-1 human breast cancer cells (MTX(R) ZR-75-1) transfected with RFC1 were 250-fold more sensitive to MTX and 300-fold more resistant to TMTX than control cell clones, showing that restoration of RFC activity has a significant impact on MTX and TMTX cytotoxicity. We also surveyed 40 of the 60 cell lines in the NCI drug screen panel for RFCI RNA levels by a quantitative RT-PCR assay. RFCI RNA levels varied over a range of 15-fold, with only 1 cell line found to be null in expression. Using data from the 6-day drug exposure assay, RFC1 correlated positively with MTX and negatively with TMTX cytotoxicity. As predicted by transfection studies, the calculated difference between MTX and TMTX potency was even more strongly correlated with RFC1 RNA levels of the cell lines. In addition, compounds in the NCI Anticancer Drug Screen database with cytotoxicity profiles which correlated with RFC1 RNA levels or with the calculated difference in MTX-TMTX potency were examined for MTX uptake inhibition and cytotoxicity in the RFC1-transfected MTX(R) ZR-75-1 cell line. Overall, our data demonstrate the importance of RFC1 in MTX resistance both as a transgene and as a constitutively expressed gene in non-selected cell lines.

Antineoplastic Agents↗

PubMed1997

Molecular mechanism of antifolate transport-deficiency in a methotrexate-resistant MOLT-3 human leukemia cell line.

Ohnuma et al reported a series of methotrexate-resistant MOLT-3 human T-cell acute lymphoblastic leukemia cell lines that showed decreasing methotrexate (MTX) uptake as the sublines acquired increasing MTX resistance (Cancer Res 45:1815, 1985). The alteration of MTX uptake kinetics in these cells, the intermediately resistant MOLT-3/MTX200 and the highly resistant MOLT-3/MTX10,000 cell lines, was attributed to a change in Vmax for methotrexate transport, without an apparent change in affinity of the transporter for MTX. We studied these cell lines to determine whether alteration of transcription or translation of the recently isolated reduced folate carrier gene (RFC1) was the cause of MTX transport deficiency in these cell lines. Reconstitution of RFC activity in MOLT-3/MTX10,000 cells by transduction with a murine RFC retroviral vector reversed MTX resistance and trimetrexate sensitivity. Although RFC1 RNA levels were unchanged in the resistant cell lines, FACS analysis using a polyclonal anti-RFC1 antibody showed no detectable RFC1 protein in the MOLT-3/MTX10,000 cells. Determination of the nucleotide sequence of RFC1 genes from MOLT-3/MTX10,000 cells revealed that this cell line contained 3 RFC1 alleles: a wild-type allele, an allele containing the premature stop codon at codon 40 and a third allele containing another mutation, which resulted in a premature stop codon at codon 25. We examined the relative expression of these alleles by determining the nucleotide sequence of 24 RFC1 cDNA subclones from MOLT-3/MTX10,000 cells and found that only one-third of these clones contained the wild-type sequence. Determination of the genomic sequence of RFC1 in MOLT-3/ MTX200 cells demonstrated that these cells were heterozygous for a mutation at codon 40, but were homozygous for the wild-type sequence at codon 25. Thus, the acquisition of MTX transport-deficiency in MOLT-3/MTX10,000 cells results from inactivating mutations of RFC1 gene alleles.

Alleles↗

PubMed1997

Regret and Responsibility in the Evaluation of Decision Outcomes

The negative affect associated with bad decision outcomes is often thought to involve feelings of remorse or self-blame. For example, studies showing greater regret associated with active than with passive choice are interpreted as the active chooser piling self-recrimination on top the disappointment of a poor outcome. Corresponding rejoicing is postulated for active choice that leads to good outcomes. The five experiments reported here challenge such a view. In each, hypothetical individuals experienced identical gains or losses, some as a result of their own choice, others as a result of an external, arbitrary process. Though evaluations of final outcomes were heavily influenced by the paths by which the outcomes were reached, and by the comparison levels that were evoked, in no case was decision agency a significant influence. In these experiments, then, the "active chooser" effect appears more a matter of change than of choice, of the route taken rather than whether one is the driver or the passenger. Further research will be needed to establish the circumstances under which different salient comparisons are evoked.

Journal Article↗

PubMed1997

The Cdc2 protein kinase controls Cdc10/Sct1 complex formation.

In the fission yeast Schizosaccharomyces pombe, the execution of Start requires the activity of the Cdc2 protein kinase and the Cdc10/Sct1 transcription complex. The loss of any of these genes leads to G1 arrest and activation of the mating pathway under appropriate conditions. We have undertaken a genetic and biochemical analysis of these genes and their protein products to elucidate the molecular mechanism that governs the regulation of Start. We demonstrate that serine-196 of Cdc10 is phosphorylated in vivo and provide evidence that suggests that phosphorylation of this residue is required for Cdc10 function. Substitution of serine-196 of Cdc10 with alanine (Cdc10 S196A) leads to inactivation of Cdc10. We show that Cdc10 S196A is incapable of associating with Sct1 to form a heteromeric complex, whereas substitution of this serine with aspartic acid (S196D) restores DNA-binding activity by allowing Cdc10 to associate with Sct1. Furthermore, we demonstrate that Cdc2 activity is required for the formation of the heteromeric Sct1/Cdc10 transcription complex and that the Cdc10 S196D mutation alleviates this requirement. We thus provide biochemical evidence to demonstrate one mechanism by which the Cdc2 protein kinase may regulate Start in the fission yeast cell cycle.

CDC2 Protein Kinase↗

PubMed1997

Ran1 functions to control the Cdc10/Sct1 complex through Puc1.

We have undertaken a biochemical analysis of the regulation of the G1/S-phase transition and commitment to the cell cycle in the fission yeast Schizosaccharomyces pombe. The execution of Start requires the activity of the Cdc2 protein kinase and the Sct1/Cdc10 transcription complex. Progression through G1 also requires the Ran1 protein kinase whose inactivation leads to activation of the meiotic pathway under conditions normally inhibitory to this process. We have found that in addition to Cdc2, Sct1/Cdc10 complex formation requires Ran1. We demonstrate that the Puc1 cyclin associates with Ran1 and Cdc10 in vivo and that the Ran1 protein kinase functions to control the association between Puc1 and Cdc10. In addition, we present evidence that the phosphorylation state of Cdc10 is altered upon inactivation of Ran1. These results provide biochemical evidence that demonstrate one mechanism by which the Ran1 protein kinase serves to control cell fate through Cdc10 and Puc1.

Cell Cycle↗

PubMed1997

The influence of psychosocial factors on heart transplantation decisions and outcomes.

In January 1990, a well-established heart transplant program added a psychosocial evaluation procedure to its medical evaluation of potential transplant recipients. To determine the predictive value of psychosocial evaluation for decisions to list patients for a transplant and for ultimate clinical outcomes, we reviewed records of 191 patients who underwent psychosocial evaluation in the subsequent 3 years. Informal prescreening for obvious psychopathology and other disqualifiers almost certainly restricted the ranges of psychosocial factors observed in the sample. Of 120 patients listed, 61 actually received transplants. Psychosocial factors were little used in deciding whether to list the patients and were not predictive of recipients' medical outcome or compliance, but were moderately predictive of complication rates and difficulty of managing patients after transplantation. Although psychosocial evaluation of prescreened potential transplant recipients has little value in predicting medical outcome, it may be useful for planning and scheduling care after transplantation.

Decision Making↗

PubMed1994

Interaction between the Cig1 and Cig2 B-type cyclins in the fission yeast cell cycle.

In this report, we describe the cloning and characterization of a B-type cyclin, Cig2 from the fission yeast Schizosaccharomyces pombe. The cig2 gene encodes a 45-kDa protein that is most similar to a previously identified B-type cyclin in S. pombe, Cdc13. Deletion of cig2 had no observable effect on cell viability or progression through the cell cycle. Strains carrying the cig2 null allele do, however, exhibit an enhanced ability to undergo conjugation relative to a wild-type strain. The cig2 transcript was found to undergo periodic oscillation during the cell cycle, peaking at the G1/S-phase boundary. We have investigated the relationship between Cig2 and the other B-type cyclins, Cig1 and Cdc13, in the fission yeast. We found that cells carrying disruptions of both the cig1 and cig2 genes contain multiple nuclei with a 1C DNA content, suggesting that they are delayed in progression through the G1 phase of the cell cycle. The phenotype of this double mutant suggests that there is a delay in septum formation, possibly as a result of defective nuclear separation.

Amino Acid Sequence↗

PubMed1993

Some contagion models of speeding.

Drivers' decision on whether or not to speed are only partially predicted by attitudes towards speeding, beliefs about the consequences of speeding, and police efforts to enforce speed restrictions. We propose that a significant role may be played by drivers' comparisons of their own speed with that of other, nearby drivers. Such comparisons may lead to self-amplifying, nonintuitive consequences at the aggregate level. We present several simple models of these social contagion processes and demonstrate analytical strategies for tracing their implications. We also present some preliminary data suggesting that significant contagion effects exist. Finally, we outline some promising directions for research on contagion effects, and trace their implications for enforcement efforts.

Automobile Driving↗

PubMed1993

GTP hydrolysis by complexes of the signal recognition particle and the signal recognition particle receptor.

Translocation of proteins across the endoplasmic reticulum membrane is a GTP-dependent process. The signal recognition particle (SRP) and the SRP receptor both contain subunits with GTP binding domains. One GTP-dependent reaction during protein translocation is the SRP receptor-mediated dissociation of SRP from the signal sequence of a nascent polypeptide. Here, we have assayed the SRP and the SRP receptor for GTP binding and hydrolysis activities. GTP hydrolysis by SRP was not detected, so the maximal GTP hydrolysis rate for SRP was estimated to be < 0.002 mol GTP hydrolyzed x mol of SRP-1 x min-1. The intrinsic GTP hydrolysis activity of the SRP receptor ranged between 0.02 and 0.04 mol GTP hydrolyzed x mol of SRP receptor-1 x min-1. A 40-fold enhancement of GTP hydrolysis activity relative to that observed for the SRP receptor alone was obtained when complexes were formed between SRP and the SRP receptor. GTP hydrolysis activity was inhibited by GDP, but not by ATP. Extended incubation of the SRP or the SRP receptor with GTP resulted in substoichiometric quantities of protein-bound ribonucleotide. SRP-SRP receptor complexes engaged in GTP hydrolysis were found to contain a minimum of one bound guanine ribonucleotide per SRP-SRP receptor complex. We conclude that the GTP hydrolysis activity described here is indicative of one of the GTPase cycles that occur during protein translocation across the endoplasmic reticulum.

Animals↗