PubMed Health⌕ Search

Biomedical subjects

E Barr

Publications and source records attributed to E Barr.

At least 19 recordsLinked to original sources
PubMed2006

High sustained efficacy of a prophylactic quadrivalent human papillomavirus types 6/11/16/18 L1 virus-like particle vaccine through 5 years of follow-up.

Human papillomavirus (HPV) causes cervical, vulvar, and vaginal cancers, precancerous dysplasia, and genital warts. We report data for the longest efficacy evaluation to date of a prophylactic HPV vaccine. In total, 552 women (16-23 years) were enrolled in a randomised, placebo-controlled study of a quadrivalent HPV 6/11/16/18 L1 virus-like-particle vaccine with vaccination at months 0, 2, and 6. At regular intervals through 3 years, subjects underwent gynaecologic examination, cervicovaginal sampling for HPV DNA, serum anti-HPV testing, and Pap testing, with follow-up biopsy as indicated. A subset of 241 subjects underwent two further years of follow-up. At 5 years post enrollment, the combined incidence of HPV 6/11/16/18-related persistent infection or disease was reduced in vaccine-recipients by 96% (two cases vaccine versus 46 placebo). There were no cases of HPV 6/11/16/18-related precancerous cervical dysplasia or genital warts in vaccine recipients, and six cases in placebo recipients (efficacy = 100%; 95% CI:12-100%). Through 5 years, vaccine-induced anti-HPV geometric mean titres remained at or above those following natural infection. In conclusion, a prophylactic quadrivalent HPV vaccine was effective through 5 years for prevention of persistent infection and disease caused by HPV 6/11/16/18. This duration supports vaccination of adolescents and young adults, which is expected to greatly reduce the burden of cervical and genital cancers, precancerous dysplasia, and genital warts.

Adolescent↗
PubMed2006

Population-based enrolment of adolescents in a long-term follow-up trial of human papillomavirus vaccine efficacy.

We evaluated a study setting for assessment of the long-term vaccine efficacy (VE) of human papillomavirus (HPV) virus-like-particle (VLP) vaccine against cervical carcinoma. A total of 22,412 16- to 17-year old adolescent women from seven cities in Finland were invited by letter to participate in a phase III study of a quadrivalent HPV (types 6, 11, 16, 18) VLP vaccine, between September 2002 and March 2003. A total of 30,947 18-year old women were invited to participate as unvaccinated controls. These women were asked about their willingness to participate in an HPV vaccination trial and to fill a health questionnaire. These three population-based cohorts of adolescent women, including women vaccinated with HPV vaccine or placebo vaccine and unvaccinated control women, are systematically followed over time. The study cohort database will be linked with the Finnish Cancer Registry using cervical carcinoma in situ (CIS) and invasive cervical carcinoma (ICC) as endpoints. Assuming that the cumulative incidence of CIS and ICC over 15 years is 0.45%, and that there is no loss to follow-up, and power of 80%, the determination of 70% total VE will require 3357 HPV vaccine recipients, 3357 placebo vaccine recipients, and 6714 unvaccinated controls. At the baseline, 2632 (12%) of the invited adolescents volunteered to the phase III vaccination trial, and 6790 (22%) responded to the questionnaire study. During a recruitment period of 10 months, 874 HPV vaccine recipients, 875 placebo recipients and 1919 unvaccinated controls were enrolled. Population-based enrollment of large cohorts of vaccinated and unvaccinated adolescents for passive registry-based follow-up with cervical carcinoma as the end-point is feasible and currently going on in Finland.

Adolescent↗
PubMed2005

Trigeminal uptake and clearance of inhaled manganese chloride in rats and mice.

Inhaled manganese (Mn) can enter the olfactory bulbs via the olfactory epithelium, and can then be further transported trans-synaptically to deeper brain structures. In addition to olfactory neurons, the nasal cavity is innervated by the maxillary division of the trigeminal nerve that projects to the spinal trigeminal nucleus. Direct uptake and transport of inhaled metal particles in the trigeminal system has not been investigated previously. We studied the uptake, deposition, and clearance of soluble Mn in the trigeminal system following nose-only inhalation of environmentally relevant concentrations. Rats and mice were exposed for 10-days (6 h/day, 5 days/week) to air or MnCl2 aerosols containing 2.3 +/- 1.3 mg/m3 Mn with mass median aerodynamic diameter (MMAD) of 3.1 +/- 1.4 microm for rats and 2.0 +/- 0.09 mg/m3 Mn MnCl2 with MMAD of 1.98 +/- 0.12 microm for mice. Mn concentrations in the trigeminal ganglia and spinal trigeminal nucleus were measured 2 h (0-day), 7-, 14-, or 30-days post-exposure using proton induced X-ray emission (PIXE). Manganese-exposed rats and mice showed statistically elevated levels of Mn in trigeminal ganglia 0-, 7- and 14-days after the 10-days exposure period when compared to control animals. The Mn concentration gradually decreased over time with a clearance rate (t1/2) of 7-8-days. Rats and mice were similar in both average accumulated Mn levels in trigeminal ganglia and in rates of clearance. We also found a small but significant elevation of Mn in the spinal trigeminal nucleus of mice 7-days post-exposure and in rats 0- and 7-days post-exposure. Our data demonstrate that the trigeminal nerve can serve as a pathway for entry of inhaled Mn to the brain in rodents following nose-only exposure and raise the question of whether entry of toxicants via this pathway may contribute to development of neurodegenerative diseases.

Administration, Inhalation↗
PubMed2001

Cardiovascular thrombotic events in controlled, clinical trials of rofecoxib.

BACKGROUND: In comparing aspirin, nonselective nonsteroidal antiinflammatory agents (NSAIDs), and cyclooxygenase (COX)-2 inhibitors, variation in platelet inhibitory effects exists that may be associated with differential risks of cardiovascular (CV) thrombotic events. Among the randomized, controlled trials with the COX-2 inhibitor rofecoxib, one study demonstrated a significant difference between rofecoxib and its NSAID comparator (naproxen) in the risk of CV thrombotic events. A combined analysis of individual patient data was undertaken to determine whether there was an excess of CV thrombotic events in patients treated with rofecoxib compared with those treated with placebo or nonselective NSAIDs. METHODS AND RESULTS: CV thrombotic events were assessed across 23 phase IIb to V rofecoxib studies. Comparisons were made between patients taking rofecoxib and those taking either placebo, naproxen (an NSAID with near-complete inhibition of platelet function throughout its dosing interval), or another nonselective NSAIDs used in the development program (diclofenac, ibuprofen, and nabumetone). The major outcome measure was the combined end point used by the Antiplatelet Trialists' Collaboration, which includes CV, hemorrhagic, and unknown deaths; nonfatal myocardial infarctions; and nonfatal strokes. More than 28 000 patients, representing >14 000 patient-years at risk, were analyzed. The relative risk for an end point was 0.84 (95% CI: 0.51, 1.38) when comparing rofecoxib with placebo; 0.79 (95% CI: 0.40, 1.55) when comparing rofecoxib with non-naproxen NSAIDs; and 1.69 (95% CI: 1.07, 2.69) when comparing rofecoxib with naproxen. CONCLUSIONS: This analysis provides no evidence for an excess of CV events for rofecoxib relative to either placebo or the non-naproxen NSAIDs that were studied. Differences observed between rofecoxib and naproxen are likely the result of the antiplatelet effects of the latter agent.

Aged↗
PubMed2001

Neutralization of human papillomavirus type 11 (HPV-11) by serum from women vaccinated with yeast-derived HPV-11 L1 virus-like particles: correlation with competitive radioimmunoassay titer.

Neutralization of human papillomavirus type 11 (HPV-11) has been demonstrated using serum and cervical secretions from primates vaccinated with virus-like particles (VLPs). Theoretically, neutralizing antibodies could protect women from HPV infection. The immunogenicity of a yeast-derived HPV-11 L1 VLP vaccine was tested in women. Serum specimens were evaluated for HPV-11 titer by competitive radioimmunoassay (cRIA) and for neutralization by use of the athymic mouse xenograft system. Analysis of serum from 104 subjects showed a dose response in HPV-11 cRIA titers and neutralization. Overall, 68 (82.9%) of 82 postimmunization serum specimens from VLP recipients were 100% neutralizing when used in the assay at a 1:50 dilution. Of 69 serum specimens, 63 (91.3%) with cRIA titers >200 milliMerck units per milliliter were neutralizing. Immunization with HPV VLPs elicits a vigorous serum immune response in a high percentage of women. The HPV-11 cRIA titer appears to be a surrogate marker for neutralization.

Adolescent↗
PubMed2001

Upstream use of tirofiban in patients admitted for an acute coronary syndrome in hospitals with or without facilities for invasive management. PRISM-PLUS Investigators.

Management and prognosis of acute coronary syndromes may be influenced by the availability of catheterization facilities at admitting hospitals. Treatment effects of tirofiban were examined in a Canadian cohort of 834 patients enrolled in the Canadian Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms (PRISM-PLUS) trial according to admission into hospitals without (n = 322) or with catheterization facilities (n = 512). Hospital transfers for cardiac catheterization were facilitated using preexisting networks accelerated for the purposes of the protocol. In hospitals without facilities, the relative risks for occurrence of death, infarction, or refractory ischemia among patients receiving tirofiban plus heparin compared with heparin alone were 0.52 at 7 days (p = 0.02), 0.59 at 30 days (p = 0.03), and 0.70 at 180 days (p = 0.09); and for death or infarction, 0.32 (p = 0.02), 0.46 (p = 0.04,) and 0.51 (p = 0.03), respectively. Benefit was seen regardless of transfer status, with no statistically significant interaction between treatment, hospital type, and catheterization for any end point at any time point. The incidence of Thrombolysis In Infarction defined major bleeding with respect to therapy was not significantly different between hospital types. Thus, upstream treatment with tirofiban plus heparin confers clinical benefits in unstable angina and/or non-ST-segment elevation infarction patients regardless of whether initial presentation is to a hospital without catheterization facilities or to a hospital with such facilities.

Acute Disease↗
PubMed2000

Glycoprotein IIb/IIIa receptor blockade improves outcomes in diabetic patients presenting with unstable angina/non-ST-elevation myocardial infarction: results from the Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms (PRISM-PLUS) study.

BACKGROUND: Diabetic patients who present with unstable angina or non-ST-elevation myocardial infarction suffer a substantially greater incidence of subsequent infarction or death compared with nondiabetic patients. The present study was undertaken to examine whether diabetic patients in the Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms (PRISM-PLUS) study appeared to benefit from platelet glycoprotein IIb/IIIa receptor-mediated inhibition of platelet aggregation by tirofiban. METHODS AND RESULTS: Of the 1570 PRISM-PLUS patients treated with either tirofiban plus heparin (n=773) or heparin alone (n=797), approximately 23% in each treatment group were diabetic. A comparison of treatment outcomes in the diabetic subgroup revealed that the combination therapy compared with heparin alone was associated with reductions in the incidence of the composite primary end point of death, myocardial infarction (MI), or refractory ischemia at 2, 7, 30, and 180 days (7.7% versus 8.3%, 14. 8% versus 21.8%, 20.1% versus 29.0%, and 32.0% versus 39.9%, respectively; P=NS) and in the incidence of MI or death (0.0% versus 3.1%, P:=0.03; 1.2% versus 9.3%, P:=0.005; 4.7% versus 15.5%, P:=0. 002; and 11.2% versus 19.2%, P:=0.03). Tests for quantitative interaction between tirofiban therapy and diabetic status were significant. CONCLUSIONS: The addition of tirofiban to heparin and aspirin appears effective in the prevention of major ischemic events, particularly MI or death, in diabetic patients presenting with unstable angina and non-ST-elevation MI.

Aged↗
PubMed2000

Effect of indomethacin on blood pressure lowering by captopril and losartan in hypertensive patients.

NSAIDs are known to attenuate the effects of some antihypertensive medications. It is not known whether the new class of angiotensin II receptor antagonists is similarly affected. We conducted a multicenter study assessing the effect of indomethacin on the antihypertensive effects of losartan and captopril. After 4 weeks of placebo washout, hypertensive patients received 6 weeks of active antihypertensive therapy with either 50 mg losartan once daily (n=111) or 25 mg captopril twice daily for 1 week, which was increased to 50 mg twice daily for 5 weeks (n=105). This was followed by 1 week of concomitant therapy with indomethacin (75 mg daily). The primary outcome measure was the change in mean 24-hour ambulatory diastolic blood pressure after the addition of indomethacin. Both captopril and losartan significantly lowered ambulatory diastolic blood pressure (losartan -5.3 mm Hg, P:<0.001; captopril -5.6 mm Hg, P:<0.001) after 6 weeks of therapy. Indomethacin significantly attenuated the 24-hour ambulatory diastolic blood pressure for both losartan (2.2 mm Hg, P:<0.05) and captopril (2.7 mm Hg, P:<0.001) and also attenuated the effect of captopril on trough sitting diastolic blood pressure. Changes in daytime diastolic blood pressure (7:00 AM to 11:00 PM) were similar to the 24-hour response in both groups. Nighttime diastolic blood pressure (11:01 PM to 6:59 AM) was significantly attenuated in captopril-treated patients (2.0 mm Hg, P:<0.05), but losartan was unaffected (0.4 mm Hg). Thus, concurrent treatment with indomethacin similarly attenuates the 24-hour antihypertensive response to losartan and captopril.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Economics, health-related quality of life, and cost-effectiveness methods for the TACTICS (Treat Angina With Aggrastat [tirofiban]] and Determine Cost of Therapy with Invasive or Conservative Strategy)-TIMI 18 trial.

Concern over escalating health care costs has led to increasing focus on economics and assessment of outcome measures for expensive forms of therapy. This is being investigated in the Treat Angina With Aggrastat [tirofiban] and Determine Cost of Therapy with Invasive or Conservative Strategy (TACTICS)-TIMI 18 trial, a randomized trial comparing outcome of patients with unstable angina or non-Q-wave myocardial infarction treated with tirofiban and then randomized to an invasive versus a conservative strategy. Hospital and professional costs initially and over 6 months, including outpatient costs, will be assessed. Hospital costs will be determined for patients in the United States from the UB92 formulation of the hospital bill, with costs derived from charges using departmental cost to charge ratios. Professional costs will be determined by accounting for professional services and then converted to resource units using the Resource Based Relative Value Scale and then to costs using the Medicare conversion factor. Follow-up resource consumption, including medications, testing and office visits, will be carefully measured with a Patient Economic Form, and converted to costs from the Medicare fee schedule. Health-related quality of life will be assessed with a specific instrument, the Seattle Angina Questionnaire, and a general instrument, the Health Utilities Index at baseline, 1, and 6 months. The Health Utilities Index will also be used to construct a utility. By knowing utility and survival, quality-adjusted life years will be determined. These measures will permit the performance of a cost-effectiveness analysis, with the cost-effectiveness of the invasive strategy defined and the difference in cost between the invasive and conservative strategies divided by the difference in quality-adjusted life years. The economic and health-related quality of life aspects of TACTICS-TIMI 18 are an integral part of the study design and will provide a comprehensive understanding of the impact of invasive versus conservative management strategies on a broad range of outcomes after hospitalization for unstable angina or non-Q-wave myocardial infarction.

Angina Pectoris↗
PubMed1998

A study of losartan, alone or with hydrochlorothiazide vs nifedipine GITS in elderly patients with diastolic hypertension.

We conducted a randomised, double-blind, parallel design study comparing the efficacy and tolerability of the angiotensin II receptor antagonist, losartan, alone or with low-dose hydrochlorothiazide (HCTZ) to the dihydropyridine calcium channel blocker, nifedipine GITS (gastro-intestinal therapeutic system), in elderly patients (> or =65 years old) with a diastolic blood pressure (DBP) between 95 and 115 mm Hg. After a placebo wash out period, 140 patients were randomly assigned to receive either losartan 50 mg or nifedipine GITS 30 mg. Patients were evaluated at 4-week intervals during a 12-week treatment period. Patients receiving losartan had HCTZ 12.5 mg added and increased to 25 mg to reduce DBP <90 mm Hg. Patients receiving nifedipine GITS had their dose increased to 60 mg and 90 mg to reduce DBP <90 mm Hg. Efficacy, tolerability and quality of life were assessed during the 12 weeks on each regimen. Patients treated with the losartan regimen (n = 73) had reductions in trough sitting DBP of -10, -13, and -13 mm Hg after 4, 8, and 12 weeks of therapy, respectively. Patients receiving the nifedipine GITS regimen (n = 67) had DBP reductions of -14, -15, and -15 mm Hg, respectively. There were no significant differences in the DBP response between the treatment groups except at week 4 (P < 0.05). Similar reductions in systolic BP (SBP) between the two treatment groups were observed at all time points. The percentages of patients in the two treatment groups reaching goal DBP (<90 mm Hg or DBP > or =90 mm Hg with a reduction from a baseline of > or =10 mm Hg) were comparable (81% on the losartan regimen and 90% on the nifedipine GITS regimen). There were significantly more adverse events reported in patients receiving nifedipine GITS when compared to the losartan regimen (54% vs 36%, P < 0.05). A patient-reported symptom inventory also showed that swollen ankles was bothersome in significantly more patients treated with the nifedipine GITS regimen when compared to the losartan regimen (24% vs 5%, P = 0.001). Thus, in elderly patients with diastolic hypertension, a regimen of losartan alone or with HCTZ has similar efficacy to a regimen of nifedipine GITS with greater tolerability and less symptom bother due to swollen ankles.

Aged↗
PubMed1998

Association of human apolipoprotein E with lipoproteins secreted by transfected McA RH7777 cells.

To examine the association of apolipoprotein (apo) E with nascent hepatic lipoproteins we have prepared stable transfectants of the rat hepatoma cell line McA RH7777 expressing the human apoE3 cDNA. When the nascent lipoproteins secreted from control cells were separated on fast protein liquid chromatography (FPLC) columns, rat apoE was detected in the very low density (VLDL) and high density lipoprotein (HDL) fractions, while rat apoA-I was found in the HDL and lipoprotein free fractions. Human apoE was also associated with the VLDL and HDL particles secreted from the transfected McA RH7777 cells. Expression of human apoE resulted in a significant decrease in the amount of rat apoA-I associated with the lipoprotein particles. Rat apoE was also displaced, but to a lesser extent. Infection of McA RH7777 cells at different multiplicities of infection with recombinant adenoviral vector containing the human apoE cDNA indicated that rat apoA-I was decreased in the HDL fractions at lower levels of expression of human apoE than was rat apoE. The HDL particles were further examined by immunoblotting of nondenaturing gradient gels and by non-denaturing immunoprecipitation. The results indicate that the high density lipoprotein (HDL) particles are heterogeneous in size and apolipoprotein composition with the majority of the rat and human apolipoproteins being located on different particles. These results suggest that the profile and concentration of HDL apolipoproteins produced in hepatocytes influences the assembly of the various subsets of secreted HDL.

Animals↗
PubMed1997

Transcriptional targeting of replication-defective adenovirus transgene expression to smooth muscle cells in vivo.

Gene transfer using replication-defective adenoviruses (RDAd) holds promise for the treatment of vascular proliferative disorders, but is potentially limited by the capacity of these viruses to infect multiple cell lineages. We have generated an RDAd vector, designated AdSM22-lacZ, which encodes the bacterial lacZ reporter gene under the transcriptional control of the smooth muscle cell (SMC)-specific SM22alpha promoter. Here, we show that in vitro AdSM22-lacZ programs expression of the lacZ reporter gene in primary rat aortic SMCs and immortalized A7r5 SMCs, but not in primary human umbilical vein endothelial cells (HUVECs) or NIH 3T3 cells. Consistent with these results, after intraarterial administration of AdSM22-lacZ to control and balloon-injured rat carotid arteries, beta-galactosidase activity was detected within SMCs of the tunica media and neointima, but not within endothelial or adventitial cells. Moreover, intravenous administration of AdSM22-lacZ did not result in lacZ gene expression in the liver or lungs. Finally, we have shown that direct injection of AdSM22-lacZ into SMC-containing tissues such as the ureter and bladder results in high-level transgene expression in visceral SMCs. Taken together, these results demonstrate that transgene expression after infection with an RDAd vector can be regulated in an SMC lineage-restricted fashion by using a transcriptional cassette containing the SMC-specific SM22alpha promoter. The demonstration of an efficient gene delivery system targeted specifically to SMCs provides a novel means to restrict expression of recombinant gene products to vascular or visceral SMCs in vivo.

Adenoviridae↗
PubMed1997

Accumulation of human papillomavirus type 16 E7 protein bypasses G1 arrest induced by serum deprivation and by the cell cycle inhibitor p21.

The E7 oncoproteins encoded by the high-risk type of human papillomaviruses (HPVs) interact with the Rb family proteins Rb, p107, and p130. The Rb family proteins associate with the factors of the E2F family to form transcription repressor complexes, which control expression of several genes essential for S-phase entry and DNA replication. The E7 oncoproteins, by interacting with the Rb family proteins, dissociate the repressor complexes involving the factors of the E2F and Rb families, leading to a release of the E2F factors in their activator forms. In this study, we have addressed the mechanism by which the HPV type 16 (HPV16) E7 stimulates the cell cycle. Using a cell line that inducibly expresses the HPV16 E7 protein, we show that an accumulation of E7 induces quiescent cells to enter S phase and that this function of E7 depends on retention of the motif involved in binding to the Rb family proteins. To study the effects of E7 on normal human cells, we generated a recombinant adenovirus that expresses the HPV16 E7 protein. Infection of normal human fibroblasts, which were arrested in G1 phase by serum deprivation, with the E7-expressing virus induced the cells to enter S phase. The E7-induced S phase entry was accompanied by an increase in the activator form of E2F, but no increase in the cyclin-dependent kinase (cdk) activity was detected. Infection of serum-stimulated fibroblasts with a recombinant adenovirus expressing the cdk inhibitor p21 inhibited progression into S phase. Coinfection with the E7-expressing virus abrogated the p21 inhibition of progression into S phase without increasing the cdk activity. These results are consistent with the notion that E7 stimulates entry into S phase through targets downstream of the cdks such as the proteins of the E2F and Rb families.

3T3 Cells↗
PubMed1996

Therapeutic effectiveness of the immunity elicited by P815 tumor cells engineered to express the B7-2 costimulatory molecule.

It is well accepted that inoculation of B7-1-transfected tumor cells into normal mice leads to tumor rejection and subsequent resistance to challenge. However, the effectiveness of B7-2-transfected tumor cells in eliciting protective antitumor immunity is less clear. Here we show that B7-2-transfected P815 tumor cells (B7-2+) are as effective as B7-1-transfected P815 tumor cells (B7-1+) in eliciting protective immunity in normal DBA/2 mice. In addition, B7-2+ cells were found to be at least as effective as B7-1+ cells retarding tumor progression when admixed with parental P815 tumor cells prior to inoculation into normal mice. Moreover, the B7-2+ cells and the B7-1+ cells were equivalent in their ability to retard tumor growth when administered peritumorally into mice bearing established (approx. 3 mm in diameter) parental P815 tumors. Finally, P815 tumor cells infected with a recombinant replication-defective adenovirus encoding the murine B7-2 gene were effective in retarding the growth of established parental P815 tumors. Thus, B7-1 and B7-2 are comparable in terms of their ability to stimulate the generation of tumor-eradicating immunity in normal mice as well as in mice bearing established parental tumors. Moreover, adenovirus vectors can be used to generate B7-2-expressing tumor cells effective in the immunotherapy of established parental tumors.

Adenoviridae↗
PubMed1995

Cytostatic gene therapy for vascular proliferative disorders with a constitutively active form of the retinoblastoma gene product.

Vascular smooth muscle cell (SMC) proliferation in response to injury is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis after balloon angioplasty. The retinoblastoma gene product (Rb) is present in the unphosphorylated and active form in quiescent primary arterial SMCs, but is rapidly inactivated by phosphorylation in response to growth factor stimulation in vitro. A replication-defective adenovirus encoding a nonphosphorylatable, constitutively active form of Rb was constructed. Infection of cultured primary rat aortic SMCs with this virus inhibited growth factor-stimulated cell proliferation in vitro. Localized arterial infection with the virus at the time of balloon angioplasty significantly reduced SMC proliferation and neointima formation in both the rat carotid and porcine femoral artery models of restenosis. These results demonstrate the role of Rb in regulating vascular SMC proliferation and suggest a gene therapy approach for vascular proliferative disorders associated with arterial injury.

Adenoviridae↗
PubMed1995

Adenovirus-mediated over-expression of the cyclin/cyclin-dependent kinase inhibitor, p21 inhibits vascular smooth muscle cell proliferation and neointima formation in the rat carotid artery model of balloon angioplasty.

Vascular smooth muscle cell (VSMC) proliferation after arterial injury is important in the pathogenesis of a number of vascular proliferative disorders, including atherosclerosis and restenosis after balloon angioplasty. Thus, a better understanding of the molecular mechanisms underlying VSMC proliferation in response to arterial injury would have important therapeutic implications for patients with atherosclerotic vascular disease. The p21 protein is a negative regulator of mammalian cell cycle progression that functions both by inhibiting cyclin dependent kinases (CDKs) required for the initiation of S phase, and by binding to and inhibiting the DNA polymerase delta co-factor, proliferating cell nuclear antigen (PCNA). In this report, we show that adenovirus-mediated over-expression of human p21 inhibits growth factor-stimulated VSMC proliferation in vitro by efficiently arresting VSMCs in the G1 phase of the cell cycle. This p21-associated cell cycle arrest is associated both with significant inhibition of the phosphorylation of the retinoblastoma gene product (Rb) and with the formation of complexes between p21 and PCNA in VSMCs. In addition, we demonstrate that localized arterial infection with a p21-encoding adenovirus at the time of balloon angioplasty significantly reduced neointimal hyperplasia in the rat carotid artery model of restenosis. Taken together, these studies demonstrate the important role of p21 in regulating Rb phosphorylation and cell cycle progression in VSMC, and suggest a novel cytostatic gene therapy approach for restenosis and related vascular proliferative disorders.

Adenoviridae↗
PubMed1995

CNS gene delivery by retrograde transport of recombinant replication-defective adenoviruses.

The ability to program recombinant gene expression in specific sets of motor and sensory neurons would facilitate the treatment of a number of acquired and inherited central nervous system (CNS) diseases. In this report, we demonstrate that intramuscular injection of replication-defective recombinant adenovirus results in high-level recombinant gene expression, specifically in the CNS motor and sensory neurons that innervate the inoculated muscles. Neural expression of the recombinant genes results from virus transport into the CNS, presumably by retrograde axonal transport. This novel method of neural gene delivery may be of value in studies designed to improve understanding and treatment of inherited and acquired neurological diseases.

Adenoviridae↗