Metallic Surface Treatment Using Electrochemical Polishing Decreases Thrombogenicity and Neointimal Hyperplasia of Coronary Stents

An abundant healing response resulting in a more pronounced neointimal hyperplasia compared to conventional balloon angioplasty remains the most important clinical problem after coronary stent implantation. In the present study the potential beneficial effect of metal surface treatment using electrochemical polishing on stent thrombogenicity and neointimal hyperplasia was evaluated in a rat A‐ V model and a porcine coronary model. An electrochemical polishing system was developed to improve surface characteristics of stainless steel stents. Topographic scanning of the stent surface using a profilometer type Taylor Holson Form Taylsurf 120L showed a significant effect on R, (arithmetic mean of the roughness height) (0.14 vs 0.04 μm: P < 0.001) and R_t (maximum rouhgness height between a peak and a valley for the sampling length) (1.44 vs 0.43 μm: P < 0.001). Thrombogenicity of polished stents (n = 6) was compared to nonpolished stents (n = 5) in a rat A ‐ V shunt model using ¹²⁵I fibrinogen and ⁵¹Cr‐labeled platelets. Total clot weight after 30 minutes was significantly lower in the polished stents (32.1 + 2.8 vs 18.1 + 4.4: P < 0.001). Also ¹²⁵I fibrinogen deposition was significantly lower in the polished stents (1.30 + 0.07 vs 0.66 + 0.04: P < 0.001). Platelet deposition, however, was not significantly reduced (12.7 + 3.4 vs 9.87 + 1.9, NS). Subsequently, the effect of electrochemical polishing on neointimal hyperplasia was evaluated in a porcine coronary model. Polished (n =10) and nonpolished stents (n =10) were randomly implanted in the right coronary artery of healthy pigs. Neointimal hyperplasia was significantly decreased in the polished stents (0.6 + 0.28 vs 0.9 + 0.34 mm²: P <0.01). Electrochemical polishing oj coronary stents results in decreased thrombogenicity and neointimal hyperplasia after stent implantation in different animal models.     

Smoking, Exercise and Dietary Behaviors Among Mothers of Elementary School-aged Children in a Rural North Carolina County

Tobacco use, poor diet, and physical inactivity are risk behaviors established during childhood and influenced by parents. Improving health habits of rural families poses particular challenges because resources may be limited in number and reach. To characterize the kinds of prevention programs needed by rural families, 501 surveys were mailed to caregivers of elementary school children living in a rural North Carolina county. Health behaviors, related attitudes, and demographic characteristics were assessed. Risk behaviors were defined as eating less than 5 fruits and vegetables a day, exercising less than 20 minutes 3 times a week, and being a smoker. Two hundred and sixty-one adults (55%) completed the surveys. Two hundred and forty-four (93%) were female, with a mean age of 37 years, 55% had a high school or less education, 89% reported at least one risk behavior, and 57% reported 2 or more risk behaviors. Female caregivers with multiple risk behaviors had lower educational levels (p < 0.007) and placed less importance on children's health behaviors (p < 0.009) than other caregivers. Female caregivers with multiple risk behaviors were no less confident they could change their behavior than those with only one risk behavior. The majority of female caregivers of elementary school children in this rural population engaged in and modeled multiple health risk behaviors for their children. Health promotion activities that address multiple risk factors and involve children are needed by young families in rural communities.     

Prevention of Restenosis by External Beam Ionizing Irradiation

Intravascular brachytherapy with gamma sources has been proved to prevent in-stent restenosis in recent clinical trials. Beta sources are also being investigated. The intravascular use of radioactive sources has raised theoretical and logistic problems and renewed the interest in teletherapy for the treatment and prevention of restenosis. We review the literature published on the use of teletherapy in animal models and compare it to brachytherapy from biological and logistic points of view. Developing technologies for stereotactic radiotreatment of moving targets may offer new solutions and are being studied.     

Albunex Does Not Increase the Sensitivity of the Lung to Pulsed Ultrasound

If cavitation in the vasculature of the lung is the physical mechanism responsible for lung hemorrhage, then addition of cavitation nuclei to the blood should enhance the bioeffect. To test the cavitation hypothesis, the extent of lung hemorrhage in mice injected with the echocontrast agent, Albunex®, was compared to lung hemorrhage in animals injected with saline. Animals were exposed for 5 minutes to 1.1-MHz pulsed ultrasound (10 μs pulse length, 100-Hz pulse repetition frequency) at a peak positive pressure at the surface of the animal of 2 MPa. This exposure is approximately twice the threshold pressure amplitude for lung hemorrhage. Lesion areas did not differ significantly in the two groups of animals and were approximately equal to the lesion area in uninjected mice from an earlier study where acoustic exposures were the same. Neither this study nor a related study of hemolysis in vivo suggests that use of Albunex in echocardiographic procedures increases the risk of bioeffects.     

Two year cumulative incidence of trunk abnormalities in a schoolpopulation in Rotterdam, The Netherlands

We conducted a study of the 2 year cumulative incidence of trunkabnormalities in a cohort of 3,071 11 year old children (1,621boys, 1,450 girls). The following data were recorded: height,weight, signs of puberty and menarche. Trunk abnormality wasassessed in the erect child (asymmetry of shoulders and waistline,imbalance of the trunk, scoliosis, lordosis, kyphosis, swaybackand flexibility) and by the forward bending test (FBT) (ribhump or lumbar prominence, persisting scoliosis, kyphosis anddeviant lateral aspect). A normal FBT both at baseline and atfollow-up was found in 84% of the boys and in 79% of the girls.The 2 year cumulative incidence of an abnormal FBT was 10% inboys and 13% in girls.     

The Ideal Thrombolytic Agent: GISSI-2 and ISIS-3

Streptokinase (SK) and tissue plasminogen activator (alteplase [tPA]) are by far the most intensively studied thrombolytic agents, but only recently a direct head-to-head comparison (GISSI-2 Trial, in which 12,490 patients have been randomized) has become available to the scientific community. This trial, with its international extension (the International tPA/SK Mortality Trial) recruited more than 20,000 patients, showed that the two drugs tested (SK and tPA) were substantially comparable as far as the clinical events were considered. ISIS-3, the largest randomized clinical trial ever performed, compares SK, tPA, and APSAC in a factorial design. Its results will be available before spring, 1991. It is likely that these two studies, if the results will be consistent, will give a definitive answer about comparison among thrombolytic drugs. As a consequence of that achievement, the interest of the scientific community will possibly be directed towards the long-term prevention of the infarct complications, namely ventricular remodeling and infarct expansion or life-threatening arrhythmias.     

A preliminary trial of fluoxetine in refractory borderline patients

Borderline personality disorder is characterized by many of the symptoms associated with serotonin dysregulation, including affective lability, suicidal behaviors, and impulsive aggression. These provide an ideal clinical model for studying the treatment of these serious symptom presentations. The recent development of selective serotonin reuptake inhibitors such as fluoxetine makes it possible to study the role of serotonin in the etiology of affective and behavioral dyscontrol in borderline personality disorder. In this preliminary medication trial, 5 borderline personality disorder patients with severe symptoms resistant to phenelzine and neuroleptics were treated openly with fluoxetine 20 to 40 mg for 8 weeks, with weekly ratings of symptoms. The findings from this work suggested efficacy for fluoxetine in treating the depressive and impulsive symptoms of refractory patients with borderline personality disorder.