Potential biobehavioral mechanisms of recurrent abdominal pain in children

To explain why otherwise healthy children experience recurrent episodes of abdominal pain (the recurrent abdominal pain syndrome, or RAP), it has been hypothesized that the child with RAP demonstrates: (1) a deficit in autonomic nervous system recovery to stress, and/or (2) an enhanced behavioral and subjective response to pain. To evaluate the validity of these assumptions, children with RAP (9–14 years) and hospital and healthy controls matched for age, sex, ethnicity and SES were exposed to a cold pressor stimulus (0 ± 1°C). Autonomic (peripheral vasomotor and heart rate), somatic (forearm EMG), subjective (pain intensity and distress), and behavioral (facial expression) responses were recorded during baseline, stressor and recovery periods. At all 4 levels of observation, the cold pressor stimulus resulted in significant autonomic, somatic, subjective and behavioral arousal. However, no significant differential response across the 3 groups was noted for any measure and, in particular, no recovery deficit in autonomic arousal was demonstrated. These findings do not support the assumption of a differential response to an acute laboratory induced stress in children with RAP compared to control children.     

The effect of hyperthermia on glucose transport in normal and thermal-tolerant Chinese hamster ovary cells

The effect of hyperthermia on glucose transport was studied in CHO cells to test the hypothesis that interference with membrane transport might be related to cell death at elevated temperatures. It was shown that passive diffusion of 2-deoxyglucose increases steadily over the temperature range 4-50 degrees C. Facilitated diffusion increases from 4 degrees C to 35 degrees C then exhibits a broad optimum before decreasing rapidly above 45 degrees C. The temperature dependence of glucose transport in thermally resistant cells was not however different from that of normal cells suggesting that this membrane transport process is not a critical target in cell killing by heat.     

Retrograde coronary sinus perfusion for myocardial protection during cardiopulmonary bypass

The pathophysiology of retrograde coronary sinus perfusion was studied in a vented, nonworking heart in vitro. The fraction of nutritional blood flow, estimated with the trapping index of radioactive microspheres (15 +/- 5 mu), is approximately one-fifth of total flow. The funoff is primarily through the thebesian system and venovenous channels, as is shown with Microfil injection studies. These results suggest that retrograde coronary sinus perfusion would be of marginal value in revascularizing a working heart but would be effective in protecting a hypothermic, nonworking myocardium. Canine experiments indicate that retrograde coronary sinus perfusion can provide efficient core cooling of the myocardium during cardiopulmonary bypass even in the presence of complete coronary artery occlusion. It is technically simple, delivers cardioplegic solutions to the myocardium without the risk of coronary ostial injury, and can be employed in the presence of severe aortic insufficiency and open aortic root. Retrograde coronary sinus perfusion therefore appears to be a valuable alternative mode of myocardial protection during cardiac operations.     

Catastrophic hemorrhage during redo sternotomy

This paper reviews the attitude of 131 surgeons to the performance of a second sternotomy incision and assesses 144 severe hemorrhages that occurred as the sternotomy was being done. Eighty-eight percent of the hemorrhages occurred in situations in which the pericardium had not been closed at the first operation. From these events and the present attitude of surgeons responding to our questionnaire, we offer advice on the management of second sternotomies and on the management of hemorrhage when it occurs.     

Early and Late Results in Pulmonary Atresia

The early and long-term results following surgical treatment of 24 infants with pulmonary atresia with an intact ventricular septum were reviewed. Pulmonary valvotomy was the operation most often performed, and we came to realize that this was effective when the preoperative right ventricular angiogram had shown an open conus up to the atretic valve. By contrast, no infant without a patent conus survived pulmonary valvotomy. We suggest that this subgroup of patients (8 of the 24 in this series) should have a systemic-pulmonary shunt followed later by reconstruction of the right ventricular outflow tract.Diminutive right ventricles will grow and dilate if a reasonable passageway is formed from right ventricle to pulmonary artery. Thus the long-term results have been excellent when this has been carried out, with normal right ventricular pressures and appearance on angiography in 7 patients followed up to 13 years.     

Distribution of coronary blood flow during cardiopulmonary bypass in pigs

The distribution of coronary blood flow during cardiopulmonary bypass in pigs was estimated by the radioactive microsphere method. Total flows during bypass were inadequate or marginal under the conditions of the experiment. The endocardial side of the myocardium was markedly underperfused when the heart remained in ventricular fibrillation during bypass. Vasodilation (with dipyridamole) or perfusion with a pulsatile pump improved the gradient, although distribution still greatly favored the epicardial side. Only when the heart remained in normal sinus rhythm during bypass was the normal distribution maintained. The implications of these experiments for explaining the lesion of left ventricular hemorrhagic necrosis are discussed.     

Reoperation for coronary graft failure: clinical and angiographic results in 43 patients.

Reoperation because of early or late coronary graft failure was performed in 43 patients who were part of a group of 1,985 patients operated on for coronary artery disease and followed for up to 7 years. Considerable variation in the results was noted depending on whether the patients were symptomatic or not before reoperation. Of the symptomatic patients, 85% were asymptomatic late (30 months) after reoperation whereas of those patients reoperated on despite the apparent lack of symptoms, 71.5% remained free from angina later on. Moreover, patency rate was high (94.4% or 17/18 grafts) in the first group and much lower (38.4% or 5/13 grafts) in those reoperated on solely on the basis of an early angiogram showing malfunctioning grafts. Patency rate was higher when the graft was totally replaced (92.3% or 12/13 restudied) rather than repaired simply through interposition of a segment of vein (37.5% or 3/8). It is apparent that results of reoperation in symptomatic patients are identical to those of an initial revascularization. On the other hand, patients who are asymptomatic despite early evidence of malfunctioning grafts should be reoperated on only when optimal angiographic conditions are present, that is, a coronary artery that is a good size, severely narrowed, and supplying a large myocardial area.     

A simple device for achieving pulsatile flow during cardiopulmonary bypass.

We describe a simple modification of the roller pump capable of producing a pulsatile flow during extracorporeal circulation. The technique is simple and can be readily duplicated in any center that uses roller pumps for cardiopulmonary bypass. Studies are in progress to evaluate the advantages of this type of perfusion.     

Short-term clinical, nutritional, and functional effects of continuous elemental enteral alimentation in children with cystic fibrosis

Ten children with cystic fibrosis, aged 3.5 to 12 years, whose weights were lower than 90% of the expected weight for height, received high-calorie elemental enteral alimentation for four weeks. Clinical, anthropometric, and biochemical evaluations as well as blood gas analyses and chest radiograph scoring were performed in all. Pulmonary function tests were performed in the five older children, and progressive exercise tests in three. These evaluations were done before, immediately after, and two months after termination of therapy. Nutritional therapy resulted in an increase of caloric intake and in dramatic weight gain, which persisted only for a short time and was mainly related to adipose tissue accretion. No functional improvement accompanied the amelioration in nutritional status. This short-term nutritional therapy in malnourished children with cystic fibrosis was effective in increasing relative weight and energy stores, but there was no evidence of any long-term functional benefit.