Restenosis and arterial remodelling after coronary angioplasty

Restenosis after coronary angioplasty (PTCA) is a complex process and is still the major problem, despite improvements in equipment and technique. Thrombus formation and intimal hyperplasia have been considered to be the main causes of the development of restenosis after primary successful angioplasty. As yet, pharmacological trials to prevent restenosis have failed to prevent it, despite the fact that the therapy has been aimed at reducing thrombus formation and intimal hyperplasia. Several new angioplasty devices have been developed. Series of observations and a few controlled trials have demonstrated restenosis rates similar to those obtained with conventional balloon angioplasty, except in the case of stent implantation, which appears to be promising. Intravascular ultrasound studies have provided new insight and a more complete understanding of the process leading to restenosis. Vascular remodeling is now considered as an important pathogenetic factor. It consists of a change in the cross-sectional vessel area and may involve an actual constriction of the artery. This may lead to lumen-narrowing and finally restenosis with minimal neointimal formation. In this review we summarise the literature on the restenosis process and the current status of the clinical trials aimed at preventing restenosis.     

Effect of intrathecal nimodipine on spinal cord blood flow and evoked potentials in the normal or injured cord

A method was developed for administering intrathecal pharmacotherapy in a rat model of spinal cord injury. The effects of intrathecal administration of nimodipine on spinal cord blood flow (SCBF) and evoked potentials (EPs) were measured in the normal and injured spinal cord. It had previously been shown that systemic nimodipine caused severe hypotension after spinal cord injury. After baseline SCBF and EPs, 15 uninjured rats were blindly allocated to one of three groups: one placebo group (n = 5); and two groups with intrathecal nimodipine, 0.05 mg/kg (n = 5), or 0.2 mg/kg (n = 5). Ten other rats received a 35 g acute clip compression injury of the spinal cord for 1 minute and, were allocated to one of two groups: placebo (n = 5); and intrathecal nimodipine 0.05 mg/kg (n = 5) given 60 min after injury. In the uninjured groups, neither 0.05 nor 0.2 mg/kg of nimodipine increased SCBF during, or 30 min after, intrathecal infusion. However, the mean arterial blood pressure (MABP) decreased significantly to 69.73.1% after the infusion of 0.2 mg/kg nimodipine and did not recover by 98 min. In all three groups of uninjured rats, the amplitude of the cerebellar EP was decreased 30 min after infusion. After spinal cord injury, there were significant decreases in MABP, SCBF and EP amplitude in both placebo and treatment groups, but there was no therapeutic benefit from nimodipine. Thus, intrathecal infusion of nimodipine did not prevent the hypotension encountered with systemic administration and exerted no beneficial effect on SCBF or EPs after acute spinal cord injury.     

Bone grafts to the nose in Binder's syndrome (maxillonasal dysplasia): a follow-up of eleven patients with the use of profile roentgenograms

Bone grafts are used to lengthen the dorsum and elevate the tip of the nose in patients with Binder's syndrome. Disappointing long-term results in some patients generally have been assumed to be a result of resorption and/or displacement of the grafts. Treatment outcome was studied in 11 patients with the use of serial profile roentgenograms. At 40 months, the mean values after surgery were reduction of the initial transplant length by 28 percent and reduction of the transplant angle by 4 degrees. The initial nose length was increased by 1 mm, and nose tip projection was increased by 2 mm. Although the mean changes of nose length and nose tip projection seemed small, treatment outcome varied considerably between patients. In contrast with earlier assumptions, no correlation could be found between the degree of transplant resorption and/or displacement and the effect of surgery on nose length and nose tip projection.     

Parents and procedures: a randomized controlled trial

INTRODUCTION: Previous work has shown that parents prefer to be present when their children undergo common invasive procedures, although physicians are ambivalent about parental presence. PURPOSE: To determine the effect of a parent-focused intervention on the pain and performance of the procedure, anxiety of parents and clinicians, and parental satisfaction with care. POPULATION: Children younger than 3 years old undergoing venipuncture, intravenous cannulation, or uretheral catheterization. SETTING: Pediatric emergency department of Boston City Hospital. DESIGN: Randomized controlled trial with three groups; parents present and given instructions on how to help their children; parents present, but no instructions given; and parents not present. INTERVENTION: The parents were instructed to touch, talk to, and maintain eye contact during the procedure. RESULTS: A total of 431 parents was randomized to the intervention (N = 153), present (N = 147), and not present (N = 131) groups. The groups were equivalent with respect to measured sociodemographic variables and parents' previous experience in the pediatric emergency department. No differences emerged with respect to pain (3-point scale measured by parent and clinician, and analysis of cry); performance of the procedure (number of attempts, completion of procedure by first clinician, time); clinician anxiety; or parental satisfaction with care. Parents who were present were more likely to rate the pain of the children as extreme/severe (52%) in comparison to clinicians (15%, kappa .07, poor agreement) and were significantly less anxious than parents who were not present. CONCLUSION: Overall, the intervention was not effective in reducing the pain of routine procedures. Parental presence did not negatively affect performance of the procedure or increase clinician anxiety. Parents who were present were less anxious than those who were not present. CLINICAL IMPLICATION: In general, parents have indicated that they want to be present when their children undergo procedures. The results of this study challenge the traditional belief that parental presence negatively affects our ability to successfully complete procedures. We should encourage parents who want to be present to stay during procedures.     

Interferon-gamma inhibits 35S incorporation in heparan sulfate synthesized by human skin fibroblasts

Glycosaminoglycans synthesized by human skin fibroblasts were simultaneously radiolabelled with D-[1-(3H)]glucosamine and Na2(35)SO4. Considering 3H incorporation, we found that IFNgamma increased the production of glycosaminoglycan synthesis, including hyaluronic acid, heparan and chondroitin/dermatan sulfate. In contrast, the production of heparan and chondroitin/dermatan sulfate was slightly decreased on the basis of the 35S signal. Furthermore, when heparan sulfate was treated with nitrous acid, the release of free 35S was greater in control than in treated cells, although the 3H patterns of depolymerization with this agent were similar. These data demonstrate that IFNgamma inhibits the incorporation of sulfate from extracellular medium into heparan sulfate.     

Why spin = 1, 2 species have no electron paramagnetic resonance signal under normal conditions: possible detection by electron paramagnetic resonance at frequency close to D value?

A universal EPR simulation program has been created by the author, which is based on the following spin Hamiltonian equation: [equation: see text] where D and E are the axial and rhombic zero-field splitting parameters, respectively. The program can be used for simulation of EPR spectra with half-integer electronic spin (S = n/2, n = 3, 5, 7, 9) systems. In this article, the integer spin (S = n/2, n = 2, 4) systems are also considered. The EPR simulation results show that when D > frequency, no EPR signal can be seen from EPR simulation; when D approximately frequency, whichever X/Q/W-band is used, the EPR signal can be seen on the basis of the simulated EPR results presented.     

Loss performance of tagged and normal ATM cells at a partiallyshared buffer

The loss performance of tagged and normal ATM cells at a first-in-first-out (FIFO) buffer is studied. The authors show that if a partial buffer sharing mechanism is adopted the loss probability of normal cells can be firmly guaranteed, regardless of the traffic intensity of tagged cells     

Kinetic study of the hydrolysis of isocyanic acid in the gas phase

The hydrolysis of isocyanic acid in the gaseous phase has been investigated at temperatures between 553 and 613 K by mass spectrometry and evaluated to obtain the corresponding kinetic data. The reaction order and reaction constant have been determined. Finally, the influence of water on the catalysed formation of melamine from isocyanic acid under the operating conditions employed has been investigated in order to determine whether there is a need to try the process gas.     

Self-ignition and combustion of a water-fuel emulsion during its injection into heated air. II. Ignition delay time of M-40 fuel oil

We studied experimentally the influence of the degree of water emulsification ofM-40 mazut heated to the water boiling point on the self-ignition time with its pulsed high-pressure injection into heated air. It is shown that water addition does not change the chemistry of the reaction and heating the water-fuel emulsion leads to the disappearance of differences in the ignition character of the emulsion and the moisture-free fuel. It is confirmed that the features of selfignition are determined mostly by conditions of mixture formation. Indirect evidence is obtained that the dynamic tensile strength of the fluid strongly influences the primary dispersion of the jet during its outflow from the sprayer nozzle.Institute of Theoretical and Applied Mechanics, Novosibirsk 630090. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 4, pp. 20–25, July–August, 1995.