Biomedical subjects

M Cushman

Publications and source records attributed to M Cushman.

At least 19 recordsLinked to original sources

PubMed2006

Plasma hemostatic factors and endothelial markers in four racial/ethnic groups: the MESA study.

BACKGROUND: Hemostatic factors and endothelial markers may play some role in racial/ethnic differences in cardiovascular disease (CVD) rates. However, little information exists on hemostatic factors and endothelial markers across racial/ethnic groups. OBJECTIVES: To describe, in four American racial/ethnic groups (Caucasian, Black, Hispanic, and Chinese), mean levels of selected hemostatic factors and endothelial markers. PATIENTS AND METHODS: Multi-ethnic Study of Atherosclerosis baseline data were used (participant age: 45-84 years). Sex-specific analysis of covariance models, and t-tests for pairwise comparisons, were used to compare means of factors and markers. Adjustments were made for demographics and traditional CVD risk factors. Differences were significant at P < 0.05. RESULTS: Blacks had the highest levels of factor VIII, D-Dimer, plasmin-antiplasmin (PAP), and von Willebrand factor, among the highest levels of fibrinogen and E-selectin (women only), but among the lowest levels of intercellular adhesion molecule 1 (ICAM-1), and, in men, the lowest levels of plasminogen activator inhibitor-1 (PAI-1). Whites and Hispanics tended to have intermediate levels of factors and markers, although they had the highest levels of ICAM-1, and Hispanics had the highest mean levels of fibrinogen and E-selectin (women only). Chinese participants had among the highest levels of PAI-1, but the lowest, or among the lowest, of all other factors and markers. No soluble thrombomodulin differences were observed. CONCLUSIONS: In this large cohort, hemostatic factor and endothelial marker mean levels varied by race/ethnicity, even after adjustment for traditional CVD risk factors.

Aged↗

PubMed2006

Hormonal factors and risk of recurrent venous thrombosis: the prevention of recurrent venous thromboembolism trial.

BACKGROUND: In some but not all studies, men with venous thrombosis had a higher risk of recurrence than women. Information on women with initial hormone-related thrombosis is scant. OBJECTIVE: We assessed the incidence of recurrent thrombosis by gender, and among women using exogenous hormones or pregnant/postpartum at the time of index thrombosis. PATIENTS/METHODS: A total of 508 men and women with one or more previous venous thrombosis episodes were observed while participating in a randomized trial of low-intensity warfarin or placebo for 2.1 years. Index thrombosis events during treatment with postmenopausal hormones, oral contraceptives, or during pregnancy, or the puerperium were considered to be hormone-related events. RESULTS: Among 268 men the 3-year probability of recurrent thrombosis was 18.4% (95% confidence intervals; CI 12.3-24.4). Among 109 women without hormone-related thrombosis, the rate was 15.0% (95% CI 6.3-23.8). Among 129 women with hormone-related thrombosis, the rate was 5.0% (95% CI 1.1-8.9). Adjusting for other risk factors and treatment assignment, women had a 39% lower thrombosis recurrence risk than men: hazard ratio (HR) 0.61 (95% CI 0.34-1.08). Women with hormone-related thrombosis had a 58% lower risk than men: HR 0.42 (95% CI 0.19-0.97); and a 46% lower recurrence risk than other women; HR 0.54 (95% CI 0.19-1.54). Women without hormone-related index events had a recurrence rate similar to men; HR 0.83 (95% CI 0.42-1.66). CONCLUSIONS: In this trial population, women had a lower risk of recurrent venous thrombosis than men. This difference was explained by a low risk of recurrence among women with hormone-related index thrombosis.

Aged↗

PubMed2006

Prospective study of subclinical atherosclerosis as a risk factor for venous thromboembolism.

BACKGROUND: Whether atherosclerotic disease predisposes to venous thrombosis is uncertain. OBJECTIVE: To determine whether subclinical atherosclerosis, manifested as increased carotid intima-media thickness (IMT) or presence of carotid plaque, is associated with increased incidence of venous thromboembolism (VTE). PATIENTS AND METHODS: The Atherosclerosis Risk in Communities study is a prospective cohort of adults aged 45-64 years, examined at baseline (1987-89) and followed for cardiovascular events. Bilateral carotid ultrasound for IMT measurements was done at baseline for portions of the common and internal carotid arteries, and carotid bifurcation and also to detect the presence of carotid plaque. Exclusion criteria included baseline anticoagulant use, history of coronary heart disease, stroke, or VTE, and incomplete data. First VTE during follow-up was validated using abstracted medical records. RESULTS: Among 13,081 individuals followed for a mean of 12.5 years, 225 first VTE events were identified. Unadjusted hazard ratios (HR) (95% CI) of VTE across quartiles of baseline IMT were 1.0, 1.16 (0.77-1.75), 1.64 (1.12-2.40), and 1.52 (1.03-2.25). However, this association disappeared after adjustment for age, sex, and ethnicity (HRs: 1.0, 1.06, 1.40, and 1.18). Further adjustment for body mass index and diabetes weakened the relative risks even further. Presence of carotid plaque at baseline also was not associated with VTE occurrence; adjusted HR = 0.97, 95% CI = 0.72-1.29. CONCLUSION: Increased carotid IMT or presence of carotid plaque was not associated with an increased incidence of VTE in this middle-aged cohort, suggesting subclinical atherosclerosis itself is not a VTE risk factor.

Atherosclerosis↗

PubMed2006

Recent exposure to particulate matter and C-reactive protein concentration in the multi-ethnic study of atherosclerosis.

Ambient levels of particulate matter have been linked to cardiovascular disease. The mechanisms mediating these associations are poorly understood. One candidate mechanism is inflammation. Using data from the Multi-Ethnic Study of Atherosclerosis (2000-2002), the authors investigated the relation between exposure to particulate matter of less than or equal to 2.5 microm in diameter (PM2.5) and C-reactive protein concentration in 5,634 persons aged 45-84 years who were free of cardiovascular disease. Data from US Environmental Protection Agency monitors were used to estimate PM2.5 exposures for the prior day, prior 2 days, prior week, prior 30 days, and prior 60 days. Only the 30-day and 60-day mean exposures showed a weak positive association with C-reactive protein, and confidence intervals were wide: relative increases in C-reactive protein per 10 microg/m3 of PM2.5 adjusted for person-level covariates were 3% (95% confidence interval (CI): -2, 10) for a 30-day mean and 4% (95% CI: -3, 11.0) for a 60-day mean. The means of 7-day, 30-day, and 60-day exposures were weakly, positively, and nonsignificantly associated with the odds of C-reactive protein of greater than or equal to 3 mg/liter: adjusted odds ratios were 1.05 (95% CI: 0.96, 1.15), 1.12 (95% CI: 0.98, 1.29), and 1.12 (95% CI: 0.96, 1.32), respectively. Slightly stronger associations were observed in persons without other risk factors for elevated C-reactive protein, but this heterogeneity was not statistically significant. The authors' results are not compatible with strong effects of particulate matter exposures on population levels of C-reactive protein.

Aged↗

PubMed2006

The association of markers of inflammation with weight change in older adults: the Cardiovascular Health Study.

OBJECTIVE: Elevated levels of inflammation factors often precede weight loss and may be causally related to it. Newer studies suggest that elevated levels of inflammation factors also precede weight gain. In this study, we examined whether inflammation factors are elevated in individuals, age >or=65 years, who lost or gained >5% weight over a 3 year follow-up period compared to those with stable weight. SUBJECTS: In total, 3254 participants in the Cardiovascular Health Study whose weight was stable; 661 who gained >5% weight; and 842 who lost >5% weight. MEASUREMENTS: C-reactive protein (CRP), fibrinogen, factor VIIIc, white blood cell (WBC) and platelet counts, and interleukin-6 (IL-6) levels. RESULTS: As compared to participants whose weight was stable, those who lost >5% weight had higher baseline CRP concentration (1.05 (95% CI, 1.02, 1.08) per interquartile increase) and WBC count (1.10 (1.01, 1.19) per interquartile increase) on adjusted analyses. Those who gained >5% weight had higher baseline CRP (1.05 (1.01, 1.08)), fibrinogen (1.13 (1.01, 1.27)), and factor VIIIc (1.15 (1.03, 1.30)). CONCLUSIONS: Inflammation factors are associated with weight gain and weight loss in older individuals. These findings suggest that subclinical inflammation, or unknown factors associated with subclinical inflammation, contribute to weight change.

Aged↗

PubMed2006

D-dimer, factor VIII coagulant activity, low-intensity warfarin and the risk of recurrent venous thromboembolism.

BACKGROUND: Elevated plasma D-dimer and factor VIII coagulant activity (FVIIIc) may be associated with the risk of recurrent venous thromboembolism (VTE). OBJECTIVES: To evaluate D-dimer and FVIIIc as risk factors for recurrent VTE and assess the efficacy of extended low-intensity warfarin (target International Normalized Ratio 1.5-2.0) in preventing recurrence by biomarker level. PATIENTS AND METHODS: In the Prevention of Recurrent Venous Thromboembolism trial, 508 idiopathic VTE patients treated for > or = 3 months with full-intensity warfarin, and who had stopped warfarin for 7 weeks on average, were randomized to low-intensity warfarin or placebo and followed for 2.1 years for recurrent VTE. Prerandomization blood samples were analysed for D-dimer and FVIIIc. RESULTS: One-third of participants had elevated baseline D-dimer (> or = 500 ng mL(-1)) and one-fourth, elevated FVIIIc (> or = 150 IU dL(-1)). Adjusting for other risk factors, the hazard ratios (HRs) for recurrent VTE with elevated D-dimer or FVIIIc were 2.0 [95% confidence interval (CI) 1.2-3.4] and 1.5 (95% CI 0.8-2.8), respectively. The association of elevated D-dimer with recurrence was larger among patients with one prior VTE (HR 3.2, 95% CI 1.3-8.0) than in patients with more than one event (HR 1.4, 95% CI 0.7-2.2). For patients with one prior VTE on placebo, the annual recurrence incidence was 10.9% with elevated D-dimer and 2.9% with normal values. Low-intensity warfarin was equally effective in recurrence risk reduction in those with normal or elevated biomarkers. CONCLUSIONS: Among patients with idiopathic VTE, measurement of D-dimer, but not FVIIIc, might be useful for risk stratification. The efficacy of extended low-intensity warfarin therapy did not vary by biomarker level.

Adult↗

PubMed2006

Subclinical atherosclerosis and the risk of future venous thrombosis in the Cardiovascular Health Study.

BACKGROUND: Recent reports have suggested an association of atherosclerosis with risk of venous thrombosis. OBJECTIVE: To confirm whether subclinical atherosclerosis is a risk factor for venous thrombosis (VT) among men and women age 65 and older. METHODS: Participants of the Cardiovascular Health Study (n = 4,108) without baseline clinical cardiovascular disease, anticoagulant use or previous VT were followed for a median of 11.7 years after non-invasive assessment of subclinical atherosclerosis using carotid ultrasound (intima-media thickness and presence of plaques), ankle-brachial blood pressure index and electrocardiogram. Each event was classified as idiopathic or secondary. We used Cox proportional hazards regression to estimate the relative risk of overall and idiopathic VT for individuals with and without baseline subclinical atherosclerosis. RESULTS: There were 133 first time VT events. No subclinical atherosclerosis measures were associated with increased risk of overall or idiopathic VT. The adjusted relative risks of overall and idiopathic VT for presence of any type of subclinical disease were 0.60 (95% confidence interval 0.39-0.91) and 0.32 (0.18-0.59), respectively. Most of this association was explained by an inverse association of high-risk carotid plaques (prevalent in 54% of those at risk) with VT. CONCLUSION: Non-invasively measured subclinical atherosclerosis was not associated with increased risk of overall or idiopathic VT in this observational study. Carotid plaques and arterial events during follow up were inversely associated, a finding that requires further study.

Aged↗

PubMed2005

Plasma fibrinogen level and the risk of major cardiovascular diseases and nonvascular mortality: an individual participant meta-analysis.

CONTEXT: Plasma fibrinogen levels may be associated with the risk of coronary heart disease (CHD) and stroke. OBJECTIVE: To assess the relationships of fibrinogen levels with risk of major vascular and with risk of nonvascular outcomes based on individual participant data. DATA SOURCES: Relevant studies were identified by computer-assisted searches, hand searches of reference lists, and personal communication with relevant investigators. STUDY SELECTION: All identified prospective studies were included with information available on baseline fibrinogen levels and details of subsequent major vascular morbidity and/or cause-specific mortality during at least 1 year of follow-up. Studies were excluded if they recruited participants on the basis of having had a previous history of cardiovascular disease; participants with known preexisting CHD or stroke were excluded. DATA EXTRACTION: Individual records were provided on each of 154,211 participants in 31 prospective studies. During 1.38 million person-years of follow-up, there were 6944 first nonfatal myocardial infarctions or stroke events and 13,210 deaths. Cause-specific mortality was generally available. Analyses involved proportional hazards modeling with adjustment for confounding by known cardiovascular risk factors and for regression dilution bias. DATA SYNTHESIS: Within each age group considered (40-59, 60-69, and > or =70 years), there was an approximately log-linear association with usual fibrinogen level for the risk of any CHD, any stroke, other vascular (eg, non-CHD, nonstroke) mortality, and nonvascular mortality. There was no evidence of a threshold within the range of usual fibrinogen level studied at any age. The age- and sex- adjusted hazard ratio per 1-g/L increase in usual fibrinogen level for CHD was 2.42 (95% confidence interval [CI], 2.24-2.60); stroke, 2.06 (95% CI, 1.83-2.33); other vascular mortality, 2.76 (95% CI, 2.28-3.35); and nonvascular mortality, 2.03 (95% CI, 1.90-2.18). The hazard ratios for CHD and stroke were reduced to about 1.8 after further adjustment for measured values of several established vascular risk factors. In a subset of 7011 participants with available C-reactive protein values, the findings for CHD were essentially unchanged following additional adjustment for C-reactive protein. The associations of fibrinogen level with CHD or stroke did not differ substantially according to sex, smoking, blood pressure, blood lipid levels, or several features of study design. CONCLUSIONS: In this large individual participant meta-analysis, moderately strong associations were found between usual plasma fibrinogen level and the risks of CHD, stroke, other vascular mortality, and nonvascular mortality in a wide range of circumstances in healthy middle-aged adults. Assessment of any causal relevance of elevated fibrinogen levels to disease requires additional research.

Adult↗

PubMed2005

Short-term effects of estrogen, tamoxifen and raloxifene on hemostasis: a randomized-controlled study and review of the literature.

INTRODUCTION: Estrogen therapy (ET), tamoxifen and raloxifene are associated with a two- to three-fold increased risk of venous thrombosis (VT); however, the mechanisms by which each drug increases venous thrombosis propensity are not fully understood. The objectives of this investigation were to compare the effects of these three treatments on hemostasis in a head to head randomized placebo-controlled trial. PATIENTS/METHODS: Ninety-four postmenopausal women were assigned to receive oral estrogen (conjugated equine estrogen [CEE] 0.625 mg, n=23), tamoxifen 20 mg (n=24), raloxifene 60 mg (n=24) or placebo (n=23) daily for 6 months. Blood samples were analyzed for procoagulant factors (prothrombin, factors VII [fVII], VIII [fVIII], IX [fIX] and XI [fXI], D-dimer and von Willebrand factor [vWf]), anticoagulant factors (antithrombin [AT], total and free protein S, protein C and activated protein C [APC] resistance) and fibrinolytic factors (thrombin activatable fibrinolysis inhibitor [TAFI] and plasminogen activator inhibitor-1 [PAI-1]), at baseline and at 6 months of treatment. RESULTS: Estrogen increased factor VII and D-dimer, and decreased antithrombin, total and free protein S and PAI-1. Changes with tamoxifen were distinct from estrogen with increases in factors VIII, IX, vWf and free protein S, and decreases in AT, total protein S, protein C and plasminogen activator inhibitor-1. Raloxifene produced similar effects as tamoxifen, but did not increase factor IX or decrease protein C. CONCLUSIONS: Estrogen, tamoxifen and raloxifene affected hemostasis favoring procoagulation and impairing anticoagulation. The biochemical effects of the selective estrogen receptor modulators (SERMs) were distinct from those of estrogen and differed only subtly from each other.

Biomarkers↗

PubMed2004

Risk factors for venous thrombosis in medical inpatients: validation of a thrombosis risk score.

BACKGROUND/OBJECTIVES: The occurrence of and risk factors for venous thrombosis (VT) complicating hospital admission in unselected medical inpatients have not been widely studied. PATIENTS AND METHODS: In a 400-bed teaching hospital we identified all cases of VT complicating hospital admission between September 2000 and September 2002 using discharge codes and chart review. Controls were randomly selected adult inpatients frequency matched to cases for medical service. RESULTS: The incidence of VT complicating hospital admission was 7.6 per 1000 admissions. On average, VT was diagnosed on the fifth hospital day. The median age of the 65 cases and 123 controls was 68 years and 45% were men. Cases had a 4-fold higher death rate than controls [95% confidence interval (CI) 1.9, 8.8]. At admission, trauma within 3 months, leg edema, pneumonia, platelet count > 350 x 10(3) mm(-3) and certain cancers were associated with risk of VT. Age, body mass index, and acute myocardial infarction were not associated with VT risk. One of three published VT risk models was able to risk stratify patients and was associated with a 2.6-fold increased risk of VT (95% CI 1.3, 5.5). Use of VT prophylaxis did not differ in cases and controls; prophylaxis was used < 1/3 of hospital days in 52% of patients. CONCLUSIONS: VT was common among medical inpatients. Of the risk factors identified, elevated platelet count has not been previously reported. Only one of three published risk scores was associated with risk of inpatient VT. Future study should improve upon risk prediction models for in-hospital VT among medical patients.

Adolescent↗

PubMed2003

Prospective study of the A455V polymorphism in the thrombomodulin gene, plasma thrombomodulin, and incidence of venous thromboembolism: the LITE Study.

Plasma thrombomodulin (soluble TM; sTM) is considered to be a marker of endothelial injury, but a recent report indicated that the relationship of sTM with thrombosis is complex. Venous thromboembolic events were identified in adults in two longitudinal cohort studies, the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study, totaling 21 690 participants. After 8 years of follow-up, sTM was measured in baseline plasma of 305 participants who developed venous thrombosis and 607 who did not. Thrombomodulin A455V genotype was determined in 302 cases and 626 controls. There was no difference in the prevalence of the three TM genotypes between cases and controls and no difference in age-adjusted mean values of sTM by genotype. There were no associations of age-adjusted sTM or TMA455V genotype with overall venous thromboembolism or with thrombosis in any subtype of venous thromboembolism.

Age Factors↗

PubMed2003

Inter-relation of coagulation factors and d-dimer levels in healthy individuals.

Recently, high levels of coagulation factor (F)VIII, FIX and FXI have been associated with an increased risk of venous thrombosis. For several coagulation factors a substantial hereditary component was found. If regulatory genes are located outside the clotting factor genes, they may regulate the levels of several proteins in the coagulation system. Thus levels would then cluster in individuals. The aim of the present study was to assess the inter-relation among levels of the pro- and anticoagulant proteins in the coagulation cascade. We also investigated the relation between the coagulation factors and d-dimer levels (marker of coagulation activity). All analyses were performed in healthy subjects, the control population of the Leiden Thrombophilia Study (LETS), to eliminate the influence of a prior thrombosis on the interpretation of the results (n = 466). Using principal-components analysis, a method intended to explain relationships among several correlated variables, we found a clustering between the vitamin K-dependent factors (prothrombin, VII, IX, X) and FXI and FXII. FV and FVIII clustered with fibrinogen and d-dimer. FXIII remained relatively independent of the other factors. Adding the anticoagulant factors to the analysis resulted in minor changes in the clustering pattern. The anticoagulant factors clustered together. We found relatively independent clusters within the group of pro- and anticoagulant factors, which may suggest that the genetic basis for high or low levels of factors in the coagulation system may, at least partly, lie outside the genes coding for these factors.

Adolescent↗

PubMed2002

Intestinal absorption and biodistribution of cosalane and its amino acid conjugates: novel anti-HIV agents.

Cosalane and its amino acid conjugates are potent inhibitors of HIV replication. The purpose of this study was to investigate: (1) the pharmacokinetic disposition of the diglycine (GC) and the diaspartic acid (ASPC) conjugates of cosalane in male Sprague-Dawley rats; (2) intestinal absorption of cosalane and its amino acid conjugates using in vitro (small intestinal segments), in situ (closed loop); and (3) biodistribution of GC and its absolute oral bioavailability in rat. Cosalane and its conjugates exhibited biexponential disposition with very long half-lives upon intravenous dosing. However, these compounds failed to permeate the small intestine unless sodium desoxycholate (5-20 mM) was used as an intestinal permeation enhancer. A rank order correlation in terms of permeation enhancement in a descending order is as follows: GC>Cosalane>ASPC. In situ studies revealed that although the bile salt enhanced the permeation of cosalane across the enterocyte, its hepatic uptake was extensive. However, 66% of the absorbed dose of GC escaped uptake by the reticuloendothelial system (RES) and its biodistribution studies showed that the uptake by the RES was significantly lower compared to the parent compound. GC had an absolute oral bioavailability of 5.10+/-1.51%. Therefore, GC appears to be a favorable candidate for further development.

Animals↗

PubMed2002

Sex hormones, hemostasis and early pregnancy loss.

AIMS: This study was designed to determine the association between coagulation factors and spontaneous abortion adjusting for sex steroids and to examine the influence of sex hormones on coagulation factors early in pregnancy. METHODS: Pregnant women presenting to the emergency department at the Hospital of the University of Pennsylvania were recruited and followed through 22 weeks gestation. Cases were women who experienced a spontaneous abortion (n=29) and controls were women who maintained their pregnancy to 22 weeks gestation (n=89). Participants completed a baseline questionnaire to assess demographic, reproductive, and drug use information. Blood samples measured estradiol, progesterone, fibrinogen, and factor VII antigen. RESULTS: Cases of spontaneous abortion had significantly lower levels of estradiol, progesterone, fibrinogen and factor VII antigen compared to controls. The relationship between low levels of fibrinogen and factor VII antigen was diminished adjusting for the sex steroids. Regression analyses found low progesterone was the primary prospective marker for early pregnancy loss among our study population. CONCLUSIONS: The relationship between coagulation factors and spontaneous abortion was reduced after adjustment for progesterone suggesting that progesterone mediates the relationship between low levels of coagulation factors and spontaneous abortion. Progesterone seems to be the primary marker for a spontaneous abortion among women seeking emergent care.

Abortion, Spontaneous↗

PubMed2001

Design, synthesis, and evaluation of 9-D-ribityl-1,3,7-trihydro-2,6,8-purinetrione, a potent inhibitor of riboflavin synthase and lumazine synthase.

Reduction of 5-nitro-6-D-ribitylaminouracil (9) afforded 5-amino-6-D-ribitylaminouracil (1), which reacted with ethyl chloroformate to yield 5-ethylcarbamoyl-6-D-ribitylaminouracil (12). The latter compound was cyclized to 9-D-ribityl-1,3,7-trihydropurine-2,6,8-trione (13), which was found to be a relatively potent inhibitor of both Escherichia coli riboflavin synthase (K(i) 0.61 microM) and Bacillus subtilis lumazine synthase (K(i) 46 microM). Molecular modeling of the lumazine synthase-inhibitor complex indicated the possibility for hydrogen bonding between the Lys135 epsilon-amino group of the enzyme and both the 8-keto group and the 4'-hydroxyl group of the ligand. A bisubstrate analogue of the riboflavin synthase-catalyzed reaction, 1,4-bis[1-(9-D-ribityl-1,3,7-trihydropurine-2,6,8-trionyl)]butane (18), was also synthesized using a similar route and was found to be inactive as an inhibitor of both riboflavin synthase and lumazine synthase.

Bacillus subtilis↗

PubMed2001

The biological effects of structural variation at the meta position of the aromatic rings and at the end of the alkenyl chain in the alkenyldiarylmethane series of non-nucleoside reverse transcriptase inhibitors.

In an effort to elucidate a set of structure-activity relationships in the alkenyldiarylmethane (ADAM) series of non-nucleoside reverse transcriptase inhibitors, a number of modifications were made at two locations: (1) the meta positions of the two aromatic rings and (2) the end of the alkenyl chain. Forty-two new ADAMs were synthesized and evaluated for inhibition of the cytopathic effect of HIV-1(RF) in CEM-SS cell culture and for inhibition of HIV-1 reverse transcriptase. The size of the aromatic substituents was found to affect anti-HIV activity, with optimal activity appearing with Cl, CH(3), and Br substituents and with diminished activity occurring with smaller (H and F) or larger (I and CF(3)) substituents. The substituents at the end of the alkenyl chain were also found to influence the antiviral activity, with maximal activity associated with methyl or ethyl ester groups and with diminished activity resulting from substitution with higher esters, amides, sulfides, sulfoxides, sulfones, thioesters, acetals, ketones, carbamates, ureas, and thioureas. Twelve of the new ADAMs displayed submicromolar EC(50) values for inhibition of the cytopathic effect of HIV-1(RF) in CEM-SS cells. Selected ADAMs, 19 and 21, were compared to previously published ADAMs 15 and 17 for antiviral efficacy and activity against the HIV-1 reverse transcriptase enzyme. All four ADAMs were found to inhibit HIV-1 reverse transcriptase enzyme activity, to inhibit the replication of a variety of HIV-1 clinical isolates representing syncytium-inducing, nonsyncytium-inducing, and subtype representative isolates, and to inhibit HIV-1 replication in monocytes. Subsequent assessment against a panel of site-directed reverse transcriptase mutants in NL4-3 demonstrated no effect of the K103N mutation on antiviral efficacy and a slight enhancement (6- to 11-fold) in sensitivity to AZT-resistant viruses. Additionally, ADAMs 19 (44-fold) and 21 (29-fold) were more effective against the A98G mutation (found in association with nevirapine resistance in vitro), and ADAM 21 was 5-fold and 2-fold more potent against the Y181C inactivation mutation than the previously reported ADAMs 15 and 17, respectively. All four ADAMs were tested for efficacy against a multidrug-resistant virus derived from a highly experienced patient expressing resistance to the reverse transcriptase enzyme inhibitors AZT, ddI, 3TC, d4T, foscarnet, and nevirapine, as well as the protease inhibitors indinavir, saquinavir, and nelfinavir. ADAM 21 was 2-fold more potent than ADAM 15 and 6-fold more potent than ADAMs 17 and 19 at preventing virus replication. Thus, we have identified a novel series of reverse transcriptase inhibitors with a favorable profile of antiviral activity against the primary mutation involved in clinical failure of non-nucleoside reverse transcriptase inhibitors, K103N, and that retain activity against a multidrug-resistant virus.

Alkenes↗

PubMed2001

Preparation and evaluation of sulfide derivatives of the antibiotic brefeldin a as potential prodrug candidates with enhanced aqueous solubilities.

Several sulfide (+)-brefeldin A (BFA) analogues were prepared through the Michael addition of various thiols. Many of the sulfides were also oxidized to the corresponding sulfoxide with m-CPBA. The sulfides were designed to act as BFA prodrugs via the metabolic oxidation to the sulfoxide and subsequent syn elimination. Kinetic experiments were used to prove that the syn elimination of the sulfoxides prepared did in fact take place. Five selenide BFA prodrugs were also prepared that are envisioned to act in the same manner as the sulfides. As expected, when oxidation of the selenide to selenoxide was attempted, in situ syn elimination was observed. All of the compounds prepared were evaluated for antiproliferative activity against human cancer cell lines in the National Cancer Institute screen. The sulfoxides were much more potent than either the sulfides or selenides. Especially notable were sulfoxide 21, which possessed a cytotoxicity mean graph midpoint value (MGM) value lower than BFA itself, and sulfoxide 22, which possessed an MGM value slightly less potent than that of BFA. The sulfide analogues were shown to possess increased aqueous solubilty with respect to BFA.

Anti-Bacterial Agents↗

PubMed2001

Solid-phase synthesis of the alkenyldiarylmethane (ADAM) series of non-nucleoside HIV-1 reverse transcriptase inhibitors.

The Sonogashira and Stille cross-coupling reactions have been employed in the synthesis of several non-nucleoside reverse transcriptase inhibitors (NNRTIs) in the alkenyldiarylmethane (ADAM) series. The synthesis has been carried out both in solution and on a solid support. In contrast to previous syntheses of NNRTIs in the ADAM series, the present strategy allows the incorporation of differently substituted aromatic rings in a stereochemically defined fashion. The most potent of the new ADAMs inhibited the cytopathic effect of HIV-1RF in CEM-SS cell culture with an EC50 value of 20 nM.

Anti-HIV Agents↗