A Novel Nucleating Agent-Based Technology Resulting in Low Density Rigid Polyurethane Foam for Appliances with Reduced Energy Consumption

Emulsion technology has proven to offer improvements to the performance of rigid polyurethane foam both in terms of general physical properties as well as for insulation performance. The presence of insoluble liquid materials generates a very fine celled structure leading to the above mentioned advantages. Earlier technological developments made in this direction made use of fully or highly fluorinated materials, an approach which became jeopardised because of the unfavourable environmental properties (especially the very high GWP) of this type of materials. A new approach has now been identified which via a similar process, results in polyurethane foam showing improved physical properties, but which doesn't offer negative environmental properties. The improved physical properties include a 10% reduction in minimum stable density in comparison to actual systems available in the market. This paper describes all aspects of this new approach, both in terms of its physical and environmental properties, as well as the final physical properties of the PU foam produced. The overall environmental impact of the different options identified using this approach also will be discussed. Several aspects of the effect of the emulsion technology on the general processing of the foam system will be highlighted. Sourcing, availability and cost impact of the new technology options will also be discussed.

Associated coronary and cardiac anomalies in the tetralogy of Fallot. An angiographic study

Numerous studies have pointed out the frequent association of tetralogy of Fallot (TF) with other cardiovascular defects and coronary tree anomalies. We found cardiac defects in 181 (68%) out of 265 patients with TF investigated by catheterization and selective coronary angiography. These anomalies were isolated in 88 cases (49%) and associated with others in 93 patients. In the case of an isolated anomaly associated with TF, the coronary tree was involved in 37.5% and the cardiovascular system in the remaining 62.5%; in the case of two anomalies, the coronary system was involved in 66% of the patients and the cardiovascular apparatus in 34%; in the case of three or more anomalies, the coronary arteries were involved in 71% and the cardiovascular system in 29%. Anomalies in the course and/or distribution of coronary arteries were present in 96 patients (36%): 10 had a single coronary ostium, 13 a left anterior descending artery arising from the right coronary artery, one a circumflex artery arising from the right coronary artery. Small fistulas between coronary arteries and the pulmonary artery were found in 20 cases; anastomoses between coronary and bronchial arteries or right atrium in 42. In 39 patients we observed a large conus artery or large anterior ventricular branches crossing the right ventricle. A right aortic arch was found in 56 patients (21%), a stenosis of the trunk and/or the peripheral pulmonary artery in 35 (13%) and pulmonary artery atresia in five. Four patients showed a complete atrioventricular canal, three an atrial septal defect (primum type) with cleft of the mitral valve, 61 (23%) an atrial septal defect (ostium secundum). Eleven patients had anomalies of the systemic venous return, 26 (10%) a patent ductus arteriosus. Four patients had valvular abnormalities. In our series, a large proportion of cardiac defects associated with TF consists of anomalies of coronary arteries. Our data confirm the usefulness of performing preoperatively routine coronary angiography in patients with complex congenital heart disease.

Coronary artery anatomy in corrected transposition of the great arteries

Congenitally corrected transposition of the great arteries is an unusual cardiac malformation with discordant atrioventricular and ventriculoarterial alignments. Because knowledge of the coronary artery anatomy is a prerequisite for successful repair of this cardiac anomaly, selective coronary arteriography was performed in 13 children (4 male and 9 female; age range 18 months to 16 years) and 1 adult (aged 59 years) with congenitally corrected transposition of the great arteries and associated intracardiac defects. The typical coronary distribution of corrected transposition (that is, coronary artery-ventricular concordance) was found in 11 patients. In one patient, a single coronary ostium was observed; the right sinus of Valsalva gave rise to a short common branch that divided into three arteries: a left circumflex artery going to the right, a well developed left anterior descending artery running into the anterior interventricular groove and a third vessel that continued on the normal course of the right coronary artery directed posteriorly. In one patient, the left circumflex artery was particularly small. In another patient, with severe hypoplasia of the left anterior descending coronary artery, the anterior ventricular wall of the heart was supplied by three small branches that ended a short distance from their origins. The adult patient had a large anterior ventricular branch arising from the morphologic left coronary ventricular as well as a large acute marginal branch, with a wide distribution, from the morphologic right coronary artery. Presurgical coronary angiographic documentation is helpful because, in congenitally corrected transposition as well as in complex congenital heart disease, coronary anomalies (in origin, course and distribution) are occasionally present and knowledge of their presence can help determine the most appropriate surgical approach.

[Surgical therapy of the dissection of the ascending aorta. Experience in the use of the G. R. F. biological glue]

Nine patients with dissecting aneurysm of the ascending aorta (type A dissection) were operated upon. Six cases had an acute dissection, whereas three cases had a chronic type of dissection. The ascending aorta was replaced with a Dacron tubular prosthesis after solidification of the external and the internal layers of the two aortic stumps using a G.R.F. biological glue. Early and late results as well as the possible complications during the post-operative course are reported. Furthermore the advantages in using the G.R.F. glue are discussed in details. They are mainly represented by the excellent solidification of the aortic stumps, by the possibility to correct the aortic regurgitation without valve replacement and particularly by a good hemostasis of the surgical sutures.

[Fixed subvalvular aortic stenosis. Monodimensional echocardiographic findings]

19 patients affected by discrete subvalvular aortic stenosis were studied by M-mode echocardiography. The diagnosis was confirmed by cardiac catheterism and angiocardiography and by anatomic evidence in operative room. The most frequent echocardiographic pattern was the abnormal protosystolic movement of aortic valve leaflets, that was found in all the patients. A discrete linear echo in the outflow tract of the left ventricle was observed in almost half of the cases. In 40% of the cases the left ventricular outflow tract was narrowed. The relations between these echocardiographic patterns and the anatomical kinds of discrete subaortic stenosis are discussed. No correlations were found between echocardiographic patterns and severity of the subaortic stenosis.

[Dyslipidemia and coronary disease. Clinico-coronarographic study]

An inverse relationship between alpha-cholesterol and coronary atherosclerosis was observed in 200 male patients given coronographies. Specifically the lowest alpha-cholesterol levels were observed in patients with the most serious and widespread atherosclerotic lesions. This inverse correlation was maintained at the same level in all age groups.

[The natural development of arteriosclerotic coronary disease. Coronarographic study in time intervals]

In 96 patients with coronary artery disease a coronary arteriography was performed twice at least with some months' interval, in order to establish the rate of progression of coronary atherosclerosis and the factors which could affect this progression. It was possible to select patients with progression of the coronary arteria lesions from patients with no increase of coronary stenosis. From the angiographic point of view, the progression of angina and the appearance of myocardial infarction are connected with a general progression of arterial lesions on all main coronary branches. As to the electrocardiographic aspects, the ECG at rest give no informations about the evolution of the coronary disease. Among the risk factors the smoking only has some importance in order to predict the progression of the coronary atherosclerosis.

Left ventricular aneurysm in a child

A child with a large ventricular aneurysm was completely free of symptoms when admitted to the hospital; a chest-x-ray previously performed because of acute pneumonia had evidenced a bulge of the left border of the heart. The diagnosis of left ventricular aneurysm was verified by left ventricular angiography. Selective coronary angiography and angiocardiography of the right heart were also performed.

[Cineangiographic and hemodynamic evaluation of left bundle branch block]

Left cardiac catheterisation, selective coronarography and ventriculography were employed in a study of 89 patients with left bundle-branch block. Three subjects presented normal haemodynamic and cineangiographic data, 16 displayed valve defects, usually of the aorta, 34 had ischaemic heart disease, and 36 cardiomyopathy mostly of a congestive type. Deviation of the axis in excess of--30 degrees on the frontal plane appeared to be more frequently accompanied by ischaemia, though this finding was not prognostic from the haemodynamic standpoint. A prolonged QRS (over 0.15") was more frequent in valvular heart disease and accompanied by more evident left valve dysfunction. Comparison between the 34 ischaemic patients and 317 coronary patients without left bundle-branch block showed that the former has a higher frequency of leftness in the distribution of their coronary circulation, and more extensive impairment of the coronary arteries, especially the ramus interventricularis anterior. Changes in left ventricle kinetics and serious hypokinesia and/or akinesia appear to be due to the heart disease responsible of the block. The series examined did not make it clear whether this intraventricular conduction defect can cause albeit slight alterations in left ventricle wall motility.

Distribution and anomalies of coronary arteries in tetralogy of fallot

The surgical management of tetralogy of Fallot (TF) may be complicated by anomalies in the course and distribution of coronary arteries. Selective coronary angiography was performed in 119 cases of TF in order to prevent injury of aberrant vessels. In 11 patients, anomalies in the origin of coronary branches were revealed (five patients with a single coronary ostium, five with the anterior descending coronary artery arising from the right coronary artery or right sinus of Valsalva, and one with the circumflex artery arising from the right coronary artery). Other findings include anastomoses between coronary and bronchial arteries, small fistulas between coronary arteries and the pulmonary artery or right atrium, and hypoplasia of the coronary tree. The onset of left anterior hemiblock after total correction of TF could possibly be explained, in cases with a dominant left pattern, by injury to the coronary system after closure of the interventricular septal defect, rather than by injury to the conduction system.

[Positive ionotropic action of glucose-1-phosphate. Clinical research during heart catheterization]

The effect of glucose-1-phosphate, administered in a single dose (5 g by slow intravenous route), on myocardial contractility was evaluated in a group of patients undergoing diagnostic cardiac catheterization. The study of the hemodynamic values observed demonstrated that glucose-1-phosphate has positive inotropic action and is able to strengthen the effect of the cardioactive glucosides.