Classification of cardiorespiratory fitness using the six-minute walk test in adults: Comparison with cardiopulmonary exercise testing.

BACKGROUND: The six-minute walk test (6MWT) distance could facilitate the assessment of cardiorespiratory fitness (CRF) in clinical practice as recommended. We aimed to develop a CRF classification using the 6MWT distance in asymptomatic adults considering the treadmill maximum oxygen uptake (V˙O2max) as the gold standard method. METHODS: We evaluated V˙O2max and 6MWT distance in 1295 asymptomatic participants aged 18-80 years (60% women). Age- and sex-related CRF was classified based on the percentiles as very low (<5th percentile), low (5th-25th percentile), regular (26th-50th percentile), good (51st-75th percentile), excellent (76th-95th percentile), and superior (>95th percentile) for both V˙O2max and 6MWT distance. We investigated the 6MWT distance cut-off (%pred.) with the highest sensitivity and specificity for identifying each V˙O2max classification. RESULTS: V˙O2max declined by 8.7% per decade in both men and women. The 6MWT distance declined by 9.3% per decade in women and 9.5% in men. We formulated age- and sex-related classification tables for CRF using the 6MWT distance. Moreover, the 6MWT distance (%pred.) showed excellent ability to identify very low CRF (6MWT distance ≤ 96%; AUC=0.819) and good ability to differentiate CRF as low (6MWT distance=97%-103%; AUC=0.735), excellent (6MWT distance=107%-109%; AUC=0.715), or superior (6MWT distance>109%; AUC=0.790). It was not possible to differentiate between participants with regular and good CRF. CONCLUSION: The CRF classification by the 6MWT distance is valid in comparison with V˙O2max, especially for identifying adults with low CRF. It could be useful in clinical practice for screening and monitoring the cardiorespiratory risk in adults.

Use of cardiopulmonary exercise testing to assess early ventilatory changes related to occupational particulate matter.

Spirometry has been used as the main strategy for assessing ventilatory changes related to occupational exposure to particulate matter (OEPM). However, in some cases, as one of its limitations, it may not be sensitive enough to show abnormalities before extensive damage, as seen in restrictive lung diseases. Therefore, we hypothesized that cardiopulmonary exercise testing (CPET) may be better than spirometry to detect early ventilatory impairment caused by OEPM. We selected 135 male workers with at least one year of exposure. After collection of self-reported socioeconomic status, educational level, and cardiovascular risk data, participants underwent spirometry, CPET, body composition assessment (bioelectrical impedance), and triaxial accelerometry (for level of physical activity in daily life). CPET was performed using a ramp protocol on a treadmill. Metabolic, cardiovascular, ventilatory, and submaximal relationships were measured. We compared 52 exposed to 83 non-exposed workers. Multiple linear regressions were developed using spirometry and CPET variables as outcomes and OEPM as the main predictor, and adjusted by the main covariates. Our results showed that OEPM was associated with significant reductions in peak minute ventilation, peak tidal volume, and breathing reserve index. Exposed participants presented shallower slope of ΔVT/ΔlnV̇E (breathing pattern), i.e., increased tachypneic breathing pattern. The OEPM explained 7.4% of the ΔVT/ΔlnV̇E variability. We found no significant influence of spirometric indices after multiple linear regressions. We conclude that CPET might be a more sensitive feature of assessing early pulmonary impairment related to OEPM. Our cross-sectional results suggested that CPET is a promising tool for the screening of asymptomatic male workers.

How do the characteristics of breast cancer diagnostic assessment programmes influence service delivery: A mixed methods study.

Diagnostic assessment programmes (DAPs) coordinate multidisciplinary teamwork (MDT), and improve wait times and patient satisfaction. No research has established optimal DAP design. This study explored how DAP characteristics influence service delivery. A mixed methods case study of four breast cancer DAPs was conducted including qualitative interviews with health-care providers and retrospective chart review. Data were integrated using multiple approaches. Twenty-three providers were interviewed; 411 medical records were reviewed. The number of visits and wait times from referral to diagnosis and consultation were lowest at a one-stop model. DAP characteristics (rural-remote region, human resources, referral volume, organisation of services, adherence to service delivery targets and one-stop model) may influence service delivery (number of visits, wait times). MDT, influenced by other DAP characteristics (co-location of staff, patient navigators, team functioning), may also influence service delivery. While the one-stop model may be ideal, all sites experienced similar and unique challenges. Further research is needed to understand how to optimise the organisation and delivery of DAP services. Measures reflecting individual, team and patient-reported outcomes should be used to assess the effectiveness and impact of DAPs in addition to more traditional measures such as wait times.

Cost analysis of breast cancer diagnostic assessment programs.

OBJECTIVES: Diagnostic assessment programs (daps) appear to improve the diagnosis of cancer, but evidence of their cost-effectiveness is lacking. Given that no earlier study used secondary financial data to estimate the cost of diagnostic tests in the province of Ontario, we explored how to use secondary financial data to retrieve the cost of key diagnostic test services in daps, and we tested the reliability of that cost-retrieving method with hospital-reported costs in preparation for future cost-effectiveness studies. METHODS: We powered our sample at an alpha of 0.05, a power of 80%, and a margin of error of ±5%, and randomly selected a sample of eligible patients referred to a dap for suspected breast cancer during 1 January-31 December 2012. Confirmatory diagnostic tests received by each patient were identified in medical records. Canadian Classification of Health Intervention procedure codes were used to search the secondary financial data Web portal at the Ontario Case Costing Initiative for an estimate of the direct, indirect, and total costs of each test. The hospital-reported cost of each test received was obtained from the host-hospital's finance department. Descriptive statistics were used to calculate the cost of individual or group confirmatory diagnostic tests, and the Wilcoxon signed-rank test or the paired t-test was used to compare the Ontario Case Costing Initiative and hospital-reported costs. RESULTS: For the 191 identified patients with suspected breast cancer, the estimated total cost of $72,195.50 was not significantly different from the hospital-reported total cost of $72,035.52 (p = 0.24). Costs differed significantly when multiple tests to confirm the diagnosis were completed during one patient visit and when confirmatory tests reported in hospital data and in medical records were discrepant. The additional estimated cost for non-salaried physicians delivering diagnostic services was $28,387.50. CONCLUSIONS: It was feasible to use secondary financial data to retrieve the cost of key diagnostic tests in a breast cancer dap and to compare the reliability of the costs obtained by that estimation method with hospital-reported costs. We identified the strengths and challenges of each approach. Lessons learned from this study have to be taken into consideration in future cost-effectiveness studies.

Evaluation of dose-response relationship between smoking load and cardiopulmonary fitness in adult smokers: A cross-sectional study.

OBJECTIVE: To evaluate the dose-response relationship between smoking load and cardiopulmonary fitness, as measured with cardiopulmonary exercise testing (CPET), in adult smokers free of respiratory diseases. METHODS: After a complete clinical evaluation and spirometry, 95 adult smokers (35 men and 60 women) underwent CPET on a treadmill. RESULTS: The physiological responses during CPET showed lower cardiorespiratory fitness levels, regardless of smoking load, with a peak [Formula: see text] lower than 100% of the expected value and a lower maximum heart rate. We observed a significant moderate negative correlation between smoking load and peak [Formula: see text] . The smoking load also presented a significant negative correlation with maximum heart rate(r=-0.36; p<0.05), lactate threshold(r=-0.45; p<0.05), and peak ventilation(r=-0.43; p<0.05). However, a dose-response relationship between smoking load quartiles and cardiopulmonary fitness was not found comparing quartiles of smoking loads after adjustment for age, sex and cardiovascular risk. CONCLUSION: There appears to be no dose-response relationship between SL and cardiopulmonary fitness in adult smokers with preserved pulmonary function, after adjusting the analysis for age and cardiovascular risk. Our results suggest that smoking cessation might be useful as the primary strategy to prevent cardiopulmonary fitness decline in smokers, regardless of smoking load. Thus, even a very low dose of tobacco use must be avoided in preventive strategies focusing on becoming people more physically active and fit.

Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults

The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.

Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults.

The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.

Intensity and physiological responses to the 6-minute walk test in middle-aged and older adults: a comparison with cardiopulmonary exercise testing

The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake ( V ˙ O 2 ) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m2, performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V ˙ O 2 in the 6MWT corresponded to 78±13% of the peak V ˙ O 2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V ˙ O 2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V ˙ O 2 mL·min-1·kg-1 = -2.863 + (0.0563×6MWDm) (R2=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.

Intensity and physiological responses to the 6-minute walk test in middle-aged and older adults: a comparison with cardiopulmonary exercise testing.

The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake ( V ˙ O 2 ) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m2, performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V ˙ O 2 in the 6MWT corresponded to 78±13% of the peak V ˙ O 2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V ˙ O 2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V ˙ O 2 mL·min-1·kg-1 = -2.863 + (0.0563×6MWDm) (R2=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.

Translating knowledge to practice: optimizing the use of guidelines.

Guidelines support health care decision-making but continue to be underused, therefore more research is needed on how they can be better developed and implemented. The same is true of mental health care, for which there is recent growing interest in improving care delivery and associated outcomes by optimizing the use of mental health care guidelines. This editorial describes the key concepts from accumulated research on guideline implementation to suggest a number of avenues for research on implementation of mental health care guidelines.

Quality improvement capacity: a survey of hospital quality managers.

Background Skilled managers are an important component of quality improvement (QI) infrastructure, but there has been little evaluation of QI infrastructure, which is needed to guide enhancement of this capacity. Methods Quality managers at 97 acute care hospitals in Ontario, Canada, were surveyed by mail to describe how their roles were integrated with QI performance objectives. Binary and scaled responses were analysed quantitatively, and open-ended responses were analysed thematically. Results The response rate was 79.4%. Many QI managers were new to their role and had no support staff despite responsibility for multiple portfolios. Respondents thought that QI objectives should be less reactive to hospital executives or boards, adverse events or demands from government and accreditation bodies, and recommended that dedicated QI managers proactively apply explicit strategic plans and engage executives and clinicians. Findings were consistent regardless of rank, staffing or hospital type. Those with master's training and greater experience were more involved in strategic planning, data analysis and communication. Conclusions QI is not well resourced in most acute care hospitals in Ontario. To develop QI capacity, investment and QI training may be required. Research should empirically establish objective performance measures of QI capacity to guide investment and evaluation.

Multidisciplinary cancer conferences: identifying opportunities to promote implementation.

BACKGROUND: Cancer care is complex and multimodal therapy is now considered the standard of care. Multidisciplinary cancer conferences (MCCs) offer a venue to prospectively discuss cancer patients and plan treatment. MCCs are believed to improve patient outcomes and consequently have been internationally adopted. The purpose of this study was to describe the prevalence of MCCs in Ontario and identify individual and organizational barriers to their adoption. METHODS: A cross-sectional, mailed questionnaire of general surgeons in Ontario, Canada who care for patients with cancer was used to assess prevalence, and organizational and individual barriers to MCC implementation. Responses were summarized overall, by hospital, and by academic status. RESULTS: The response rate was 44.2% (170/385). Respondents worked at 57 unique hospitals, of which 29 (52%) were reported to have MCCs, including all academic hospitals (7/7) and 22 of 50 (44%) community hospitals. Forty-nine MCCs were reported at 29 hospitals. MCCs occurred weekly at academic centers and biweekly or monthly at community hospitals. Few MCCs (28%) had a designated coordinator. Surgeons perceived that MCCs helped them to incorporate multidisciplinary opinions into their patient care plans, improved collegiality, and provided opportunity for continuing professional development. CONCLUSIONS: Despite the perceived benefits expressed by respondents, administrative support for MCCs may be minimal. In particular, surgeons at community hospitals may have limited access to multidisciplinary patient care planning. This information will be utilized to shape a provincial strategy for implementing MCCs. However, further research is required to understand barriers and enablers to establish and maintain MCCs, especially in community practice.

Cholesterol oxides as biomarkers of oxidative stress in type 1 and type 2 diabetes mellitus.

BACKGROUND: Oxidative stress plays an important role in the pathophysiology of diabetes mellitus. The aim of this study was to evaluate the formation of cholesterol oxides (ChOx) as biomarkers of oxidative stress in subjects with impaired glucose tolerance (IGT) and diabetes. METHODS: Blood plasma levels of cholesterol oxidation products were determined in the following groups: type 1 diabetes mellitus (DM1), type 2 diabetes (DM2), impaired glucose tolerance (IGT), children without diabetes (C1) and adults without diabetes (C2). The serum levels of cholest-5-ene-3alpha,7alpha-diol (7alpha-hydroxycholesterol, 7alpha-OH), cholest-5-ene-3beta,7beta-diol (7beta-hydroxycholesterol, 7beta-OH), 3beta-hydroxycholest-5-7-one (7-ketocholesterol, 7-K), 5alpha-cholestane-3beta,5,6beta-triol (cholestanetriol), 5,6alpha-epoxy-5alpha-cholestan-3alpha-ol (cholesterol-5alpha,6alpha-epoxide,), 5,6beta-epoxy-5beta-cholestan-3beta-ol (cholesterol-5beta,6beta-epoxide) and cholest-5-eno-3beta,25-diol (25-hydroxycholesterol, 25-OH) (trivial name and abbreviations indicated in parentheses) were quantified by gas chromatography using flame ionization detection. RESULTS: The levels of total ChOx were elevated in the DM1 and DM2 groups compared to age-matched subjects without diabetes (p < 0.05). The concentrations of 7beta-hydroxycholesterol, cholesterol-alpha-epoxide and cholesterol-beta-epoxide were higher in the blood plasma of subjects in the DM2 group than in the blood plasma of subjects in the C2 and IGT groups (p < 0.05). Treatment of type 2 diabetic patients with oral hypoglycemic drugs associated with insulin resulted in lower concentrations of nitrotyrosine in the blood plasma without significant changes in the concentrations of glucose and glycated hemoglobin. Moreover, combination with statins in both treatments decreased the concentrations of ChOx. CONCLUSIONS: ChOx are suitable biomarkers of oxidative stress and may be useful in clinical studies to follow drug effects on lipid oxidative modifications in diabetic patients.

Cholesterol oxides as biomarkers of oxidative stress in type 1 and type 2 diabetes mellitus / Cholesterol oxides as biomarkers of oxidative stress in type 1 and type 2 diabetes mellitus

Background Oxidative stress plays an important role in the pathophysiology of diabetes mellitus. The aim of this study was to evaluate the formation of cholesterol oxides (ChOx) as biomarkers of oxidative stress in subjects with impaired glucose tolerance (IGT) and diabetes. Methods Blood plasma levels of cholesterol oxidation products were determined in the following groups: type 1 diabetes mellitus (DM1), type 2 diabetes (DM2), impaired glucose tolerance (IGT), children without diabetes (C1) and adults without diabetes (C2). The serum levels of cholest-5-ene-3£/,7£/-diol (7£/-hydroxycholesterol, 7£/-OH), cholest- 5-ene-3£],7£]-diol (7£]-hydroxycholesterol, 7£]-OH), 3£]-hydroxycholest-5-7- one (7-ketocholesterol, 7-K), 5£/-cholestane-3£],5,6£]-triol (cholestanetriol), 5,6£/-epoxy-5£/-cholestan-3£/-ol (cholesterol-5£/,6£/-epoxide,), 5,6£]-epoxy- 5£]-cholestan-3£]-ol (cholesterol-5£],6£]-epoxide) and cholest-5-eno-3£],25-diol (25-hydroxycholesterol, 25-OH) (trivial name and abbreviations indicated in parentheses) were quantified by gas chromatography using flame ionization detection. Results The levels of total ChOx were elevated in the DM1 and DM2 groups compared to age-matched subjects without diabetes (p < 0.05).The concentrations of 7£]-hydroxycholesterol, cholesterol-£/-epoxide and cholesterol-£]-epoxide were higher in the blood plasma of subjects in the DM2 group than in the blood plasma of subjects in the C2 and IGT groups (p < 0.05). Treatment of type 2 diabetic patients with oral hypoglycemic drugs associated with insulin resulted in lower concentrations of nitrotyrosine in the blood plasma without significant changes in the concentrations of glucose and glycated hemoglobin. Moreover, combination with statins in both treatments decreased the concentrations of ChOx.Conclusions ChOx are suitable biomarkers of oxidative stress and may be useful in clinical studies to follow drug effects on lipid oxidative modifications in diabetic patients. Copyright ÆÉ 2006 John Wiley & Sons, Ltd.

Suramin analogs inhibit human angiogenesis in vitro.

BACKGROUND: Suramin is a polysulfonated naphthylurea that inhibits tumor cell proliferation and angiogenesis, but the widespread use of this drug has been limited by significant neurologic toxicity. A series of suramin analogs that may exhibit less toxicity in vivo have been synthesized. We hypothesized that these novel analogs would have antiangiogenic properties equal to or greater than those of suramin when evaluated in an in vitro human placental vein angiogenesis model. METHODS: Human placental veins (n = 72 per group) were cultured in a 0.3% fibrin clot for a period of 14 days. Three suramin analogs (NF 145, NF 248, NF 293) and suramin were tested at 56 and 560 microM concentrations to determine their effect on the development of an angiogenic response. Experiments were repeated for each analog on veins from three different placentas. The percentage of wells that initiated an angiogenic response was calculated and compared with initiation in a control group (n = 141). RESULTS: The three suramin analogs inhibited angiogenesis in a dose-dependent fashion, with all compounds exhibiting near-complete inhibition of angiogenesis at 560 microM. The effects of these analogs were equal to or greater than those of suramin. CONCLUSION: Suramin analogs with structural alterations inhibit human angiogenesis at concentrations equivalent to those seen in vivo. These analogs may be more effective antiangiogenic agents than suramin and may have less potential for toxicity.

The effect of a lectin from the venom of the snake, Bothrops jararacussu, on tumor cell proliferation.

Lectins have been used extensively as histochemical probes to describe changes in tumor cell surface and are known to influence the growth of cancer cells. In this study, we determined the effect of a lectin from the venom of Bothrops jararacussu (BJcuL) on the proliferation of a number of established human cancer cell lines. The growth of eight cancer cell lines was inhibited in a dose-related manner in the presence of BJcuL lectin. This lectin was most potent as an inhibitor of growth in renal (Caki-1 and A-498) and pancreatic (CFPAC-1) cancer cell lines with 50% inhibitory concentrations (IC50) of 1-2 mM. Melanoma (Wm115) and prostate (PC-3) cancer cells showed IC50 values of 7.9 and 8.5 mM, respectively, in the presence of BjcuL lectin whereas colon (Caco-2) and breast (MCF7) cancer cell lines showed no effect. Our results suggest that BJcuL lectin is an effective inhibitor of cell growth in some cancer cell lines.

Uptake of suramin by human microvascular endothelial cells.

We have demonstrated for the first time that suramin is taken up by human dermal microvascular endothelial (HMEC-1) cells by an active process involving the caveolae system. The uptake of suramin was time-dependent and reduced by more than 90% when incubated in the presence of albumin or at 4 degrees C. Suramin uptake was also inhibited when incubated in the presence of filipin and digitonin, both potent cholesterol-binding agents, but not in the presence of probenecid. The [3H]suramin taken up by the HMEC-1 cells was located primarily within the nucleus, followed by the cytoplasmic fraction. The presence of suramin in these cellular compartments suggests that this drug may act through intracellular mechanisms.

Suramin analogues with a 2-phenylbenzimidazole moiety as partial structure; potential anti HIV- and angiostatic drugs, 2: Sulfanilic acid-, benzenedisulfonic acid-, and naphthalenetrisulfonic acid analogues.

The synthesis of suramin analogues bearing a 2-phenyl-benzimidazole moiety is described. Aminoarene sulfonic acids 2a-e are acylated with 3,4-dinitrobenzoyl chloride 3 yielding the amides 4a-e which are hydrogenated to the corresponding diamines 5a-e. These are treated with 3-nitrobenzaldehyde, yielding the azomethines 7a-e and their isomers 8a-e and 9a-e. Key step in the synthesis of the target compounds 12a-e is the oxidation of the azomethines with oxygen to the benzimidazoles 10a-e. These are hydrogenated to the amines 11a-e reacting with phosgene to yield the symmetric ureas 12a-e. Results of the anti-HIV, cytostatic, and antiangiogenic screening are presented.

Antiangiogenic and antiproliferative activity of suramin analogues.

The purpose of this study was to test the ability of 70 polyanionic analogues of suramin to inhibit angiogenesis. The ID50, the dose that produced 50% inhibition of angiogenesis, was determined for suramin and each of the analogues by measuring the ability of various amounts to inhibit angiogenesis in vivo in the chick egg chorioallantoic membrane (CAM) assay. Of the 70 analogues, 11 had antiangiogenic activities similar to suramin and an additional 7 were significantly more potent than suramin. All seven of these analogues were from the naphthalenetrisulfonic acid group and contained large urea groups. The benzene sulfonic and disulfonic acid analogues were less active inhibitors of angiogenesis than the naphthalenetrisulfonic acid analogues. Replacement of the naphthalenetrisulfonic acid groups by aliphatic carboxylic acids or benzoic acid gave analogues with very little antiangiogenic activity. In subsequent experiments, the antiproliferative activity of selected analogues on basic FGF (bFGF)-stimulated growth of immortalized human microvascular endothelial cells in vitro was determined. Analogues that inhibited angiogenesis to a greater extent than suramin in the CAM assay generally showed a greater antiproliferative effect on bFGF-induced growth of human microvascular endothelial cells. These results suggest that some of the polyanionic analogues may be potent therapeutic agents for cancers and angiogenesis-dependent diseases.