Purification and characterization of human cell--cell adhesion molecule 1 (C-CAM1) expressed in insect cells

The cell--cell adhesion molecule 1 (C-CAM1) plays an important role as a tumor suppressor for prostate cancer. Decreased expression of C-CAM1 was detected in prostate, breast, and colon carcinoma. Reexpression of C-CAM1 in prostate and breast cancer cell lines was able to suppress tumorigenicity in vivo. These observations suggest that C-CAM1 may be used as a marker for cancer detection or diagnosis. To generate monoclonal antibodies specific to C-CAM1, we have overexpressed full-length human C-CAM1 in Sf9 cells using a baculovirus expression system. The protein was purified 104-fold using nickel affinity chromatography. About 0.4 mg purified C-CAM1 was obtained from 200 mg of infected cells. When the purified protein was digested with peptidyl-N-glycosidase, the apparent mobility of the protein on SDS--PAGE changed from 90 to 58 kDa, which is close to the molecular weight predicted from the cloned cDNA sequence. This observation suggests that C-CAM1 was glycosylated on asparagine residues when expressed in Sf9 cells. Western blotting and internal protein sequencing analysis confirmed that the purified protein is human C-CAM1. Biochemical and functional assays indicate that this protein expressed in Sf9 cells displays characteristics similar to those of native protein, including adhesion function and glycosylation modification. Using this protocol, sufficient quantity of this protein can be produced with purity suitable for monoclonal antibody generation and biochemical study.

Increased plasma homocysteine is an independent predictor of new atherothrombotic brain infarction in older persons

A prospective study investigated the association of plasma homocysteine and other risk factors with the incidence of atherothrombotic brain infarction (ABI) at 31 +/- 9 month follow-up in 153 men and 347 women (mean age 81 +/- 9 years, median age 82). The stepwise Cox regression model showed that significant independent predictors of new ABI in older persons were age (risk ratio 1.060 for each 1-year increase of age), plasma homocysteine (risk ratio 1.079 for each 1 micromol/L increase), prior ABI infarction (risk ratio 3.282), current cigarette smoking (risk ratio 2.687), hypertension (risk ratio 2.965), and diabetes mellitus (risk ratio 2.015).

Association of mitral annular calcium with prior thromboembolic stroke in older White, African-American, and Hispanic men and women

Prior thromboembolic stroke was present in 57 of 188 white men (30%) with mitral annular calcium (MAC) and in 62 of 303 white men (20%) without MAC, in 42 of 65 African-American men (65%) with MAC and in 50 of 123 African-American men (41%) without MAC, and in 13 of 27 Hispanic men (48%) with MAC and in 21 of 58 Hispanic (36%) without MAC. Prior thromboembolic stroke was present in 164 of 614 white women (27%) with MAC and in 85 of 516 white women (16%) without MAC, in 111 of 193 African-American women (58%) with MAC and in 77 of 225 African-American women (34%) without MAC, and in 36 of 69 Hispanic women (52%) with MAC, and in 17 of 58 Hispanic women (29%) without MAC.

Association of left ventricular hypertrophy and chronic atrial fibrillation with the incidence of new thromboembolic stroke in 2,384 older persons

In a prospective study of 2,384 persons, mean age 81 years, at 44-month follow-up, new thromboembolic stroke developed in 510 of 2,384 persons (21%). The Cox regression model showed that significant independent risk factors for new thromboembolic stroke were atrial fibrillation (risk ratio 3.2), left ventricular hypertrophy (risk ratio 2.8), prior stroke (risk ratio 2.2), and male gender (risk ratio 1.2).

Association of extracranial carotid arterial disease and chronic atrial fibrillation with the incidence of new thromboembolic stroke in 1,846 older persons

In a prospective study of 1,846 persons, mean age 81 +/- 8 years, 281 persons (15%) had 40% to 100% extracranial carotid arterial disease and 253 persons (14%) had chronic atrial fibrillation. The Cox regression model showed that significant independent risk factors for new thromboembolic stroke were atrial fibrillation (p = 0.0001, risk ratio 3.3), 40% to 100% extracranial carotid arterial disease (p = 0.0001, risk ratio 2.5), prior stroke (p = 0.0001, risk ratio 2.1), and male gender (p = 0.045, risk ratio 1.2).

Risk factors for new atherothrombotic brain infarction in older African-American men and women

Independent risk factors for new atherothrombotic brain infarction (ABI) in older African-American men were hypertension (risk ratio 4.381), diabetes mellitus (risk ratio 2.872), and previous ABI (risk ratio 1.904). Independent risk factors for new coronary events in older African-American women were cigarette smoking (risk ratio 2.754), hypertension (risk ratio 5.914), diabetes mellitus (risk ratio 3.464), serum total cholesterol (risk ratio 1.008), serum high-density lipoprotein cholesterol (inverse association) (risk ratio 0.958), age (risk ratio 1.026), and previous ABI (risk ratio 2.601).

Incidence of new thromboembolic stroke in persons 62 years and older with chronic atrial fibrillation treated with warfarin versus aspirin

OBJECTIVE

To investigate the incidence of new thromboembolic (TE) stroke in older persons with chronic atrial fibrillation treated with oral warfarin versus aspirin.

DESIGN

In an observational study of 312 older persons with chronic atrial fibrillation, long-term aspirin 325 mg daily was administered to 187 persons, and oral warfarin, in a dose adjusted to maintain the international normalized ratio (INR) between 2.0 and 3.0, was administered to 115 persons. The incidence of new TE stroke was analyzed in persons treated with warfarin versus aspirin at 36 +/- 17 months (1 to 99 months) follow-up.

SETTING

A large, long-term healthcare facility.

PATIENTS

The patients included 208 women and 104 men, mean age 84 +/- 7 years (range 62 to 101 years).

MEASUREMENTS AND MAIN RESULTS

Four of 125 persons (3%) on warfarin stopped taking warfarin compared with four of 187 persons (2%) on aspirin who stopped taking aspirin because of adverse effects (P not significant). In persons with prior stroke, the incidence of new TE stroke was 40% (27 of 67) in persons treated with warfarin versus 81% (56 of 69) in persons treated with aspirin (P < .001). In persons with no prior stroke, the incidence of new TE stroke was 22% (13 of 58) in persons treated with warfarin versus 56% (66 of 118) in persons treated with aspirin (P < .001). The incidence of new TE stroke in all subjects was 32% (40 of 125) in persons treated with warfarin versus 65% (122 of 187) in persons treated with aspirin (P < .001). Cox regression analysis showed that persons taking warfarin had a 76% less chance of developing a new TE stroke than those taking aspirin after controlling the confounding effects of other risk factors.

CONCLUSION

In an observational study of older persons with chronic atrial fibrillation, persons treated with oral warfarin to maintain an INR between 2.0 and 3.0 had a significantly lower incidence of new TE stroke than persons treated with oral aspirin 325 mg daily.

Risk factors for new thromboembolic stroke in patients > or = 62 years of age with chronic atrial fibrillation

In a prospective study of 312 older patients with chronic atrial fibrillation, at 36-month follow-up evaluation, new thromboembolic stroke developed in 162 of 312 patients (52%). Significant independent risk factors for new thromboembolic stroke were prior stroke (risk ratio = 1.6), rheumatic mitral stenosis (risk ratio = 2.0), left ventricular (LV) hypertrophy (risk ratio = 2.8), abnormal LV ejection fraction (risk ratio = 1.8), serum total cholesterol (risk ratio = 1.005), and serum high-density lipoprotein cholesterol (risk ratio = 0.96).

Association of mitral annular calcium with new thromboembolic stroke at 44-month follow-up of 2,148 persons, mean age 81 years

We investigated in a prospective study of 2,148 persons (mean age 81 years), the association between mitral annular calcium and new thromboembolic stroke at 44-month follow-up. Independent risk factors for new thromboembolic stroke were prior stroke (risk ratio 2.4), mitral annular calcium (risk ratio 2.6), atrial fibrillation (risk ratio 3.0), and male gender (risk ratio 1.6).

Association of plasma renin activity and echocardiographic left ventricular hypertrophy with frequency of new coronary events and new atherothrombotic brain infarction in older persons with systemic hypertension

In older hypertensive persons, male gender, prior coronary artery disease, prior atherothrombotic brain infarction (ABI), and echocardiographic left ventricular (LV) hypertrophy are independent risk factors for new coronary events; age, prior ABI, and echocardiographic LV hypertrophy are independent risk factors for new ABI. The data suggest that high plasma renin activity in hypertensive older persons is associated with a high risk of new coronary events and of new ABI through its association with echocardiographic LV hypertrophy.

Association of extracranial carotid arterial disease, prior atherothrombotic brain infarction, systemic hypertension, and left ventricular hypertrophy with the incidence of new atherothrombotic brain infarction at 45-month follow-up in 1,482 older patients

Comparison of 239 older patients with 40% to 100% extracranial carotid arterial disease (ECAD) with 1,243 older patients with no significant ECAD showed a higher prevalence of systemic hypertension, left ventricular (LV) hypertrophy, and prior atherothrombotic brain infarction (ABI) and a higher incidence of new ABI in patients with ECAD than in patients without ECAD. A multivariate Cox regression model showed that independent predictors of new ABI were ECAD (risk ratio = 2.5), systemic hypertension (risk ratio = 2.3), prior ABI (risk ratio = 2.3), LV hypertrophy (risk ratio = 2.3), and male sex (risk ratio = 1.3).

Risk factors for new atherothrombotic brain infarction in 664 older men and 1,488 older women

The relation between obesity and new ABI is also unclear. The Framingham Study found that relative weight was not a risk factor for new ABI in older men but was a weak risk factor for new ABI in older women. Barrett-Connor and Khaw found no association between body mass index and new ABI in older men or women. The present study showed that obesity was not a risk factor for new ABI in older men. Obesity was a risk factor for new ABI in older women by univariate analysis but not by multivariate analysis. However, because obesity is associated with other risk factors for ABI and new coronary events, we would try to lower weight in obese older men and women.

Prevalence of atrial fibrillation and association of atrial fibrillation with prior and new thromboembolic stroke in older patients

OBJECTIVE

To correlate atrial fibrillation with the incidence of new thromboembolic (TE) stroke in older patients with and without prior TE stroke.

DESIGN

In a prospective study of 2101 older patients, electrocardiograms showed that atrial fibrillation was present in 283 patients (13%). At 42-month mean follow-up, atrial fibrillation was associated with the incidence of new TE stroke in patients with and without prior TE stroke.

SETTING

A large long-term health care facility where 2101 older patients were studied.

PATIENTS

The 2101 patients included 1451 women and 650 men, mean age 81 +/- 8 years (range 60 to 103).

MEASUREMENTS AND MAIN RESULTS

Atrial fibrillation was present in 283 of 2101 patients (13%). The mean age was 84 +/- 7 years in patients with atrial fibrillation and 81 +/- 8 years in patients with sinus rhythm (P = .0001). The prevalence of atrial fibrillation was 5% in patients aged 60 to 70 years, 14% in patients aged 71 to 80 years, 13% in patients aged 81 to 90 years, and 22% in patients aged 91 to 103 years (P < .0001). Mean follow-up was 31 +/- 18 months in patients with atrial fibrillation and 44 +/- 27 months in patients with sinus rhythm (P = .0001). Previous TE stroke occurred in 123 of 283 patients (43%) with atrial fibrillation and in 431 of 1818 patients (24%) with sinus rhythm (P < .0001). New TE stroke occurred in 131 of 283 patients (46%) with atrial fibrillation and in 303 of 1818 patients (17%) with sinus rhythm (P < .0001). The log-rank test showed that patients with atrial fibrillation had a significantly higher probability of developing new TE stroke than those with sinus rhythm (P < .0001). The multivariate Cox regression model showed that independent risk factors for new TE stroke were male sex (relative risk = 1.3), prior TE stroke (relative risk = 3.1), and atrial fibrillation (relative risk = 3.3).

CONCLUSIONS

Atrial fibrillation, prior TE stroke, and male sex are independent risk factors for the development of new TE stroke in older patients.

Correlation of paroxysmal supraventricular tachycardia, atrial fibrillation, and sinus rhythm with incidences of new thromboembolic stroke in 1476 old-old patients

The relationship between supraventricular tachycardia and the incidence of thromboembolic stroke has not been previously reported. We investigated in a prospective study the incidence of new thromboembolic stroke in 1476 patients, mean age 81 years, with atrial fibrillation, paroxysmal supraventricular tachycardia, or sinus rhythm detected by 24-hour ambulatory electrocardiograms. New thromboembolic stroke developed at 31-month follow-up in 87 of 201 patients (43%) with atrial fibrillation, at 43-month follow-up in 84 of 493 patients (17%) with paroxysmal supraventricular tachycardia, and at 45-month follow-up in 143 of 782 patients (18%) with sinus rhythm (p < 0.0001 comparing atrial fibrillation with paroxysmal supraventricular tachycardia or sinus rhythm). Kaplan-Meier survival curves showed a higher significance of thromboembolic stroke in patients with atrial fibrillation, compared to patients with paroxysmal supraventricular tachycardia or sinus rhythm (log-rank: p < 0.0001). Multivariate Cox regression model showed that independent significant predictors of thromboembolic stroke were: a) atrial fibrillation (relative risk = 3.31); b) prior thromboembolic stroke (relative risk = 2.85); c) sex (relative risk for women = 0.75); and d) age (relative risk = 1.02). These data show that atrial fibrillation is an independent predictor of thromboembolic stroke in elderly patients, and that paroxysmal supraventricular tachycardia is not associated with thromboembolic stroke.

Association of silent myocardial ischemia with new atherothrombotic brain infarction in older patients with extracranial internal or common carotid arterial disease with and without previous atherothrombotic brain infarction

OBJECTIVE

To correlate silent myocardial ischemia with the incidence of new atherothrombotic brain infarction (ABI) in older patients with 40 to 100% extracranial carotid arterial disease (ECAD) with and without prior ABI.

DESIGN

In a prospective study of 208 older patients with 40 to 100% ECAD diagnosed by carotid duplex ultrasonography, 24-hour ambulatory electrocardiograms were obtained to detect silent myocardial ischemia. At 42-month mean follow-up, silent myocardial ischemia was correlated with the incidence of new ABI in patients with and without prior ABI.

SETTING

A large long-term health care facility where 208 older patients with 40 to 100% ECAD and technically adequate 24-hour ambulatory electrocardiograms for detecting silent myocardial ischemia were studied.

PATIENTS

The 208 patients included 68 men and 140 women, mean age 81 +/- 8 years (range 60 to 100). One-hundred three (50%) of the patients had prior ABI.

MEASUREMENTS AND MAIN RESULTS

Sixty-nine (33%) of the 208 patients had silent myocardial ischemia. Mean follow-up was 42 +/- 25 months (range 3 to 101 months). At follow-up, the incidence of new ABI was 64% in patients with prior ABI and 32% in patients with no prior ABI (P < .0001). At follow-up, the incidence of new ABI was 65% in patients with silent ischemia and 40% in patients with no silent ischemia (P = .0005). The multivariate Cox regression model showed that patients with prior ABI have a 2.5 times higher chance of developing new ABI than those without prior ABI after controlling other prognostic variables. Patients with silent ischemia have a 2.1 times higher probability of developing new ABI than those without silent ischemia after controlling other prognostic variables.

CONCLUSIONS

Prior ABI and silent ischemia are independent risk factors for the development of new ABI in patients with 40 to 100% ECAD. This probably reflects that silent ischemia is a marker for more advanced or more significant atherosclerotic disease rather than a causal factor for ABI.

Extracranial carotid arterial disease: a prognostic factor for atherothrombotic brain infarction and cerebral transient ischemic attack

A prospective study investigated the prevalence of extracranial carotid arterial disease by carotid duplex ultrasonography, and evaluated its correlation with the incidence of atherothrombotic brain infarction or cerebral transient ischemic attack in 949 patients, mean age 82 +/- 8 years. The mean follow-up period was 45 months. Of 949 patients, 37 (4%) had 80%-100% extracranial carotid disease (mean follow-up, 24 +/- 15 months), 113 (12%) had 40%-80% extracranial carotid disease (40 +/- 19 months follow-up), and 799 (84%) had 0%-40% extracranial carotid disease (47 +/- 14 months follow-up). The average annual incidence of atherothrombotic brain infarction was 37% in patients with 80%-100% extracranial carotid disease, 9% in patients with 40%-80% extracranial carotid disease, and 4% in patients with 0%-40% extracranial carotid disease. The average annual incidence of transient ischemic attack was 3% in patients with 80%-100% extracranial carotid disease, 2% in patients with 40%-80% extracranial carotid disease, and 1% in patients with 0%-40% extracranial carotid disease. The Cox proportional hazard model showed that among the variables evaluated, the severity of extracranial carotid disease correlated with the highest relative risk of developing atherothrombotic brain infarction (2.5x higher relative risk) or transient ischemic attack (2.8x higher relative risk). Patients with an earlier atherothrombotic brain infarction had a 2.1x higher probability of developing atherothrombotic brain infarction and a 1.9x higher chance of developing transient ischemic attack than those without an earlier atherothrombotic brain infarction. Age was a prognostic variable for new atherothrombotic brain infarction, and male sex was a prognostic variable for new transient ischemic attack.

Three-year follow-up of risk factors correlated with new atherothrombotic brain infarction in 708 elderly patients

A prospective study correlated cigarette smoking, systolic or diastolic hypertension, diabetes mellitus, hypercholesterolemia, low serum high-density lipoprotein cholesterol, hypertriglyceridemia, and obesity with development of new atherothrombotic brain infarction in 192 elderly men and 516 elderly women. Mean follow-up was 36 +/- 6 months (range 19-39). New atherothrombotic brain infarction occurred in 24 of 192 men (13%) and in 63 of 516 women (12%), difference not significant. Risk factors for atherothrombotic brain infarction in elderly men were cigarette smoking (p less than 0.001), systolic or diastolic hypertension (p less than 0.001), and diabetes mellitus (p less than 0.005). Risk factors for atherothrombotic brain infarction in elderly women were systolic or diastolic hypertension (p less than 0.001), diabetes mellitus (p less than 0.001), and obesity (p less than 0.005).