The clamshell approach for the surgical treatment of complex cardiopulmonary pathology in infants and children

BACKGROUND: The surgical approach to children with complex cardiovascular and pulmonary anomalies is still controversial. Staged operations through multiple incisions are often performed in this setting. OBJECTIVE: The different applications and clinical advantages of a bilateral thoracosternotomy approach to complex cardiothoracic disease requiring surgical repair were reviewed retrospectively. METHODS: Between January 1993 and June 1995, 33 patients, aged between 2 months and 17 years (mean 7.8 +/- 5.3) underwent surgical treatment of complex cardiovascular or pulmonary disease using a clamshell approach. Twenty-one patients (64%) had undergone 1-5 previous surgical procedures (mean 2.5 +/- 1.0/patient). The technique involved supine position placement, submammary incision, access to the pleural space bilaterally through the fourth intercostal space and transverse division of the sternal body. RESULTS: Four groups of patients were operated on via this approach: (1) patients undergoing lobar, lung or heart-lung transplantation (40%); (2) patients undergoing repair of tetralogy of Fallot/pulmonary atresia (36%); (3) patients with previously corrected miscellaneous procedures (12%), including completion of Fontan, one-stage repair of left main bronchial stenosis and atrial septal defect, one-stage repair of partial anomalous pulmonary venous connection and aortic coarctation, and repair of congenital pulmonary venous stenosis. There were two early (< 30 days) deaths, giving a perioperative mortality of 6% for the entire series. Complications included postoperative hemorrhage in 4 patients (12%), prolonged ventilation time due to mechanical failure in 4 (12%). There were no wound infections. Analysis of complications by group showed the lung transplant group to be more affected (18% of patients experienced complications). Except for 2 infants undergoing complete unifocalization and presently awaiting completion of repair of tetralogy of Fallot/pulmonary atresia, in the remaining 31 (94%) a definitive surgical treatment could be performed in one-stage. CONCLUSIONS: The bilateral thoracosternotomy allows optimal exposure of all intrathoracic anatomic structures making one-stage surgical repair possible in a variety of complex cardiovascular and pulmonary anomalies. Early mortality and technique-related morbidity do not differ from those reported with the conventional approaches to the different disease conditions. A wider application of the clamshell approach for the management of complex intrathoracic pathology in infants and children is advocated.     

Temperature changes in a model of the rabbit's body under extreme cooling taking into account the effect of Arrhenius' law on the intensity of heat production

A device automatically regulating the intensity of heating when simulating the metabolism level in the rabbit heat-physical model, was compared with the similar results obtained in live rabbits. The results coinciding quite well, the findings suggest that the model's behaviour is quite adequate in experiments with profound cooling.     

Liver transplantation for primary and metastatic liver cancers

Halotherapy was used for sanatorium rehabilitation in 29 patients with chronic obstructive pulmonary diseases (chronic bronchitis and asthma). Significant positive effects of this method resulted in the improvement of the flow-volume parameters curve of lung function and in hypotensive effects on blood pressure. Halotherapy is recommended for use in patients suffering from chronic obstructive pulmonary diseases with hypertension or coronary heart disease.     

A New “Contact-Based” First Year Engineering Course*

A new first year, engineering orientation course has been put in place at NCSU. The course stresses integration with other first year courses, writing, team building, critical thinking, disciplinary thinking, and has a strong problem-solving component. Students were randomly selected to participate in the course. Students' attitudes about engineering and the first year experience were assessed using an instrument developed at the University of Pittsburgh and compared with the normal introduction to engineering course. Students in this course were more positive about their learning experience in the first semester, reported a higher satisfaction with all their courses, and were less likely to think that the first year courses were designed to “weed” students out of the program.     

Autistic behavior in young boys with fragile X syndrome

BACKGROUND: Various studies have demonstrated the benefits of continuous nebulization therapy for delivering aerosols of the beta2 agonists such as terbutaline sulfate or albuterol sulfate to patients with severe asthma and/or impending respiratory failure. OBJECTIVE: The purpose of this investigation was to explicate the operational factors associated with the use of nebulizers for extended aerosol respiratory therapy including those factors that affect the prescribed aerosol dosages and the relationship to actual delivery of prescribed drugs to the respiratory airways of the lungs of a patient under treatment conditions. METHODS: Operational characteristics and methods have been investigated for use of long-running nebulizers for continuous nebulization therapy. Factors considered were particle size distribution, setup conditions, aerosolization concentrations and rates, delivery fraction of aerosol reaching patient, and changes in medication concentration during extended operation. With a large volume nebulizer, aerosols can be delivered to the patient without dilution via a standard open mask for up to eight hours without refill. The pneumatic HEART nebulizer with 240 mL reservoir was evaluated. RESULTS: The nebulizer was operated from a single compressed air or oxygen source and found to provide from 10 to 15 L/min of aerosol with 38 to 50 microL of aerosolized medicine per liter of air (or oxygen) and utilize from 30 to 56 mL/hour of medicinal liquid. The mass median aerodynamic diameter of the aerosol droplets was found to be about 2.0 microm (sigma(g) = 2.7). Delivery efficiency to the patient mask was about 90%. The aerosolized medicine delivered to the patient can be increased by adjusting the flow rate of the gas source or changing the solution concentration of medicine. Typically, several milligrams of drug can be delivered to the patient as inhaled aerosol per hour of treatment of which about one-quarter can be expected to be deposited in the lungs. During eight hours of operation the concentration of medicinal solution increased by about a factor of two because of water evaporation. CONCLUSIONS: Continuous nebulization therapy is an important means of treating patients with severe asthma. Dosage criteria can be established based on the operating characteristics of the nebulizer system, drug solution concentration, and patient respiration.     

Activation of the ras-mitogen-activated protein kinase pathway and phosphorylation of ets-2 at position threonine 72 in human ovarian cancer cell lines

The activation status of the ras pathway was studied in eight ovarian tumor cell lines. Three biochemical parameters indicative of ras activation were tested: (a) the ratio of the ras-GTP:ras-GDP complex; (b) the activity of mitogen-activated protein kinases p42/p44; and (c) ets-2 phosphorylation at position threonine 72, a mitogen-activated protein kinase phosphorylation site in vivo. Four of the ovarian tumor cell lines had an activated ras pathway by these three parameters, whereas only one of these contained a mutated ras gene. In addition, ras/ets-2 responsive genes such as the urokinase plasminogen activator (uPA) were activated in these four cell lines. Transient transfection assays indicated that the compound ets-AP1 oncogene responsive enhancer present in the uPA gene was the target of ras signaling in ovarian tumor cells and that the combination of activated ras and ets-2 could superactivate the uPA enhancer element. Coexpression of the dominant-negative ras-Asn17 cDNA gene abrogated activity of this uPA element in ovarian tumor cells. These data indicate that ets-2 is a nuclear target of ras action in ovarian tumor cell lines and that ras signaling pathways may be activated in ovarian cancer by mechanisms independent of direct genetic damage to ras genes.     

Comparison of methods to assess visual impairment from glare and light scattering with posterior capsule opacification

PURPOSE: To compare 2 glare tests to determine their relative usefulness in the assessment of posterior capsule opacification (PCO) and to evaluate the potential benefits of combined visual, acuity, contrast sensitivity, and glare testing. SETTING: Teaching hospital ophthalmology department. METHODS: Sixteen patients had glare, visual acuity, and contrast sensitivity testing before and after neodymium:YAG (Nd:YAG) capsulotomy. Results with the Brightness Acuity Tester (BAT, Mentor), which measures disability glare, and the Straylightmeter (Foundation for Eye Research, The Netherlands), which quantifies forward scatter by direct compensation techniques, were compared. The correlation between glare, ETDRS visual acuity, and Pelli-Robson contrast sensitivity was determined. RESULTS: Pretreatment visual acuity was significantly correlated with contrast sensitivity (P < .01). However, visual acuity and contrast sensitivity were poorly correlated with both the BAT and Straylightmeter (P > .05), indicating that visual acuity is predictive of contrast sensitivity but a poor predictor of glare. Glare was significantly improved (Straylightmeter, P < .0001; BAT, P < .05) following capsulotomy. While the Straylightmeter consistently measured precapsulotomy forward scatter that improved with treatment, corresponding BAT disability glare was unmeasurable in 18.8% of patients with PCO, as their visual acuities improved rather than deteriorated with glare testing. CONCLUSIONS: Glare testing provided more information than contrast sensitivity when combined with visual acuity in the evaluation of PCO. Glare related to PCO is better assessed using the Straylightmeter because the BAT may yield aberrant disability glare results.     

Limited flexibility of the inter-protofilament bonds in microtubules assembled from pure tubulin

The superposition of the regular arrangement of tubulin subunits in microtubules gives rise to moiré patterns in cryo-electron micrographs. The moiré period can be predicted from the dimensions of the tubulin subunits and their arrangement in the surface lattice. Although the average experimental moiré period is usually in good agreement with the theoretical one, there is variation both within and between microtubules. In this study, we addressed the origin of this variability. We examined different possibilities, including artefacts induced by the preparation of the vitrified samples, and variations of the parameters that describe the microtubule surface lattice. We show that neither flattening nor bending of the microtubules, nor changes in the subunit dimensions, can account for the moiré period variations observed in 12 and 14 protofilament microtubules. These can be interpreted as slight variations, in the range -0.5 A to +0.9 A, of the lateral interactions between tubulin subunits in adjacent protofilaments. These results indicate that the inter-protofilament bonds are precisely maintained in microtubules assembled in vitro from pure tubulin. The fact that the moiré period is not affected by bending indicates that the local interactions between tubulin subunits are sufficiently stiff to accommodate large deformations of the microtubule wall.