Bicarbon valve -- European multicenter clinical evaluation

OBJECTIVE

Fifteen collaborating centers in eight countries present their pooled experience with the new Bicarbon bileaflet valve.

METHODS

Between 4/90 and 4/96, 1351 patients, 806 males and 545 females, aged 10 to 83, mean 58.4 +/- 12.4, underwent valve implantation.

OPERATIONS

aortic valve replacement (AVR), 726; mitral valve replacement (MVR), 475; double valve replacement (DVR), 150. Additional procedures: CABG, 211; TV repair, 64; other, 152.

RESULTS

Mortality: 67 early (seven valve related) and 56 late (40 valve related). Valve thrombosis: six obstructive, three non-obstructive; embolism: nine major cerebral, 37 other. Major bleeding: 29. Hemolysis: two clinically significant. Non-structural dysfunction: 24 paravalvular leaks, one leaflet interference. No structural failure! Endocarditis: 24. Reoperation 48: 22 non-structural dysfunctions, 14 endocarditis, seven thrombosis and embolism, five other. Estimated 5-year freedom from valve-related deaths is 97.2% for AVR and 92.4% for MVR; 4-year freedom from valve related deaths for DVR is 90.5%. Mean calculated NYHA improvement is 1.24.

CONCLUSIONS

The Bicarbon mechanical prosthesis is well designed, durable, has good hemodynamic features and an acceptably low incidence of complications.

Proarrhythmic and antiarrhythmic effects of bupivacaine in an in vitro model of myocardial ischemia and reperfusion

BACKGROUND

Bupivacaine may have toxic cardiovascular effects when accidentally administered by intravascular injection. However, its electrophysiologic effects in the presence of myocardial ischemia remain unknown. The authors evaluated the electrophysiologic and anti- and proarrhythmic effects of bupivacaine in an in vitro model of the ischemic and reperfused myocardium.

METHODS

In a double-chamber bath, a guinea pig right ventricular muscle strip was subjected partly to normal conditions and partly to simulated ischemia followed by reperfusion. The electrophysiologic effects of bupivacaine were studied at 1, 5, and 10 microM concentrations.

RESULTS

Bupivacaine (5 and 10 microM) decreased the maximal upstroke velocity of the action potential (Vmax) in normoxic conditions and further decreased (10 microM) the Vmax decrease induced by ischemic conditions. Bupivacaine reduced the mean occurrence time to the onset of myocardial conduction blocks (9 +/- 3 min; mean +/- SD; P < 0.005 with 5 and 10 microM, compared with 17 +/- 6 min during simulated ischemia with no drug or control), and it increased the number of preparations that became inexcitable to pacing (55% of preparations, with 1 microM and 100% with 5 and 10 microM, compared with 17% for the control group). The incidence of spontaneous arrhythmias was reduced by 5 and 10 microM bupivacaine during ischemia and reperfusion and was enhanced by 1 microM bupivacaine during the ischemic phase.

CONCLUSIONS

In guinea pig myocardium under ischemic conditions, bupivacaine induced a loss of excitability at concentrations of 5 and 10 microM. Proarrhythmic effects observed at 1 microM were considered as lower than the cardiotoxic range in normoxic conditions. The incidence of reperfusion arrhythmias was decreased at all concentrations.

Pulmonary artery trunk leiomyosarcoma

Pulmonary artery leiomyosarcomas are rare tumors. They cause symptoms suggestive of recurrent pulmonary emboli. As in the case reported here, the diagnosis is virtually never considered initially, despite modern diagnostic imaging methods, but usually made at autopsy or at histologic examination of material removed from the pulmonary artery at surgery. The prognosis remains poor and prolongation of life up to 6 months has not been clearly demonstrated with radical excision in conjunction with radiotherapy. The difficulty is the accurate diagnosis required to consider these tumors for curative resection, which is the only hope for a longer disease-free course.

[Ehlers-Danlos disease revealed during pregnancy through the diagnosis of aortic dissection]

Dissection of the aorta is a serious condition but rare in young women, and occurring during the 3rd trimester of pregnancy. The main risk factors are hypertension and diseases of the connective tissue or of collagen (Marfan's syndrome and Ehlers-Danlos disease). The authors report a case of dissection of the aorta managed in a pluridisciplinary manner by the anaesthetists, cardiologists, obstetricians and cardiothoracic surgeons, which resulted in a favourable outcome for both mother and baby. The diagnosis of Ehlers-Danlos disease was made from the onset and, over a period of 10 years with CT scan and annual echocardiographic follow-up, total replacement of the supra-coronary aorta was performed in several stages.

Pregnancy with aortic dissection in Ehler-Danlos syndrome. Staged replacement of the total aorta (10-year follow-up)

Pregnancy complicated by aortic dissection in patients with hereditary disorder of connective tissue presents interesting considerations including management of caesarean section with the unexpected need for cardiac surgery in emergency. Generalizations can be made on management principles with long-term follow-up requiring an aggressive individualized approach by a multidisciplinary team. A 33-year-old parturient presenting an aortic dissection at 37 weeks gestation required prompt diagnosis of Ehlers-Danlos syndrome in combination with correct surgical therapy resulted in the survival of both the mother and infant. During the 10-year follow-up, multiple complex dissection required transverse aortic arch and thoracoabdominal aortic replacement.

Alternative technique for the ostium primum defect repair: a free wall flap of right atrium

An alternative surgical technique of repair of the ostium primum septal defect without the use of any patch is reported. The potential technical difficulties and surgical consideration are discussed.

Aorto-pulmonary fistula: a rare event in the evolution of a dissecting aneurysm of the thoracic aorta

The natural history of a thoracic aneurysm is usually towards the dissection or free rupture; rarely an aorto-pulmonary fistula can complicate this lesion. We present two cases of Aorto-pulmonary fistula as acute complication of an aneurysm of thoracic aorta; the etiopathology seem to be related to the same mechanism: a dissecting aneurysm of the ascending aorta leading to a secondary fistulation in the main pulmonary artery. In our two cases the diagnosis was suggested by clinical findings and by Doppler-echocardiography. Both patients were managed surgically with success and both survived.

The pattern of monocyte recruitment in tumors is modulated by MCP-1 expression and influences the rate of tumor growth

Macrophage infiltration is an important aspect of the host response to tumor growth. Tumor-associated macrophages often exhibit intratumoral or peritumoral infiltration patterns. However, the mechanism that mediates distinctive patterns of macrophage infiltration and their impact on tumor growth is not known. We studied macrophage infiltration and the effect of this infiltration on tumor growth in mice inoculated with four human tumor cell lines. We report here that tumor cells producing high levels of monocyte chemoattractant protein-1 (MCP-1) had earlier recruitment of intratumoral macrophages than did lower producers and nonproducers. These MCP-1 high producers also had a lower tumor take rate than tumors that produced little or no MCP-1. The importance of early recruitment of monocytes was further demonstrated by introduction of fMLP (a chemotactic peptide) to the tumor sites. Administration of fMLP abolished the tumor formation when applied at the time of tumor-cell inoculation. When injection of fMLP was delayed, tumor growth was slowed but not eliminated. We also demonstrated that all MCP-1-producing tumors exhibited both intratumoral and peritumoral macrophage patterns, whereas MCP-1 nonproducers exhibited a peritumoral macrophage pattern only. The number of intratumoral macrophages was negatively correlated with tumor size. Collectively, our results suggest that (a) early recruitment of monocytes inhibits tumor growth; and (b) early intratumoral macrophage infiltration in vivo corresponds to the level of MCP-1 produced by tumors in vitro. In contrast, recruitment of neutrophils was not negatively correlated with tumor growth. Thus, early recruitment of macrophages may be beneficial to cancer patients.

Asymptomatic carotid stenosis in patients undergoing major cardiac surgery: can percutaneous carotid angioplasty be an alternative?

OBJECTIVE

As the mortality associated with coronary artery bypass grafts has fallen, morbidity has become an increasing problem. The improvement of transluminal carotid angioplasty is enlarged to patients with asymptomatic severe carotid stenosis (> 85%) requiring coronary surgery.

METHODS

Between January 1993 and January 1995, 10 patients underwent percutaneous carotid angioplasty prior to cardiac surgery (17.4 days). Mean age was 71 +/- 4.3 years. Four patients showed a contralateral occlusion of the internal carotid artery. Transluminal carotid angioplasty was carried out with a triple coaxial catheter system. Six angioplasties required a Strecker stent.

RESULTS

Mean follow-up was 11.4 months. No mortality was observed. Only one patient showed a transient hemianopsia. All patients underwent angiography at four months. Two patients required a new procedure of carotid angioplasty completed with a Strecker stent in one case and by dilatation of a stent in another patient.

CONCLUSION

The results of transluminal carotid angioplasty, in this short series, are encouraging in this group of high-risk morbidity and mortality (elderly patients, bilateral carotid lesions, multiple coronary arterial grafts).

Leiomyosarcoma of the inferior vena cava: novel surgical reconstruction preserves renal function

Leiomyosarcoma of the inferior vena cava is rare and to date 145 cases have been reported. Here a new case of primary leiomyosarcoma of the inter-renal vena cava is reported. Surgical treatment consisted of excision of the vena cava on top of the renal arteries allowing radical resection. Reconstruction was original. The distal vena cava was sectioned and ligated just above the bifurcation and the free segment used to replace the excised part. In this the right venal vein was directly implanted. The left renal vein was reimplanted in the translocated segment via a venous (femoral vein) graft. Ligation of the distal vena cava was haemodynamically well-tolerated and the patient was free of symptoms at one year after operation. Control angiogram showed patency of the venous reconstruction. Early diagnosis is essential to improve patient survival, since it allows better radical resection, which is the only way of preventing the development of metastases.

[Value of carbon in the thrombogenicity of cardiovascular prostheses]

Forty five Carbon-lined (CL) and 45 Standard (ST) 4 mm internal diameter polytetrafluoroethylene (PTFE) grafts were implanted as aortic interpositions in 90 New Zealand rabbits. In a pilot study of 20 animals, 10 CL and 10 ST grafts were used to develop microsurgical techniques, then 60 grafts were placed in 60 rabbits with lower morbidity. The 2-hour graft patency (Doppler study, Transonic flow probe and 8 mHZ) showed a better patency rate in the CL group (93% versus 80%). In 10 animals, platelet accumulation was investigated in vivo using scintigraphy after injection of autologous platelets labeled with Indium111. In vitro, radioactivity counting of the explanted midgrafts sections at 2 hours revealed a 6-fold higher activity in ST grafts (6.60 +/- 1.98 x 103 platelets/mm2 versus 0.82 +/- 0.25 x 103 platelets/mm2; p < 0.05). Light microscopy found platelet and fibrin deposition (PFD) in nearly all ST grafts, whereas PFD were found in only 13% of the CL grafts corresponding to those thrombosed grafts (chi2:61.117; p < 0.001). Carbon-lining decreases platelet accumulation on PTFE grafts and the rabbit aortic interposition appears to constitute a quantitative and reproducible model for investigation of antithrombotic drugs.

[Associated carotid and coronary lesions: carotid endoluminal angioplasty before coronary surgery]

OBJECTIVE

There is debate over the therapeutic strategy in patients with lesions of both the coronary arteries and the carotid arteries. Improvement in angioplasty techniques for the carotid artery would be a minimally invasive alternative.

METHODS

Between January 1993 and June 1995, 12 patients who underwent endoluminal angioplasty of the carotid artery before coronary bypass surgery (mean 17.9 days before) were included in the study. Mean age was 70 +/- 3.2 years. The carotid lesions were asymptomatic in all patients who had stable angina.

RESULTS

The mean number of bypasses was 2.9 per patient. Five patients had a contralateral stenosis of the internal carotid artery. Angioplasty was performed under cerebral protection using a three way coaxial catheter. A Strecker stent was required in 8 cases. One patient presented transient hemianopsia. All patients were seen again at 4 months for an angiogram then at 6 months for a Doppler examination. One patient needed complete redilatation with a stent and one other required dilatation of the stent.

CONCLUSIONS

Endoluminal angioplasty of the carotid arteries gave encouraging results in this high-risk population (underlying disease, age, bilateral carotid lesions, arterial coronary grafts). This technique should be used more widely for patients with severe multiple arterial lesions.

Synthesis of inositol 2-phosphate-quercetin conjugates

The antiproliferative flavonoid, quercetin, is limited in its pharmacological utility by its low water solubility. In this paper, we describe the synthesis of two quercetin analogues prepared by linking the hydroxyl group at the 3- or 5-position of the flavonoid to the 1-hydroxyl group of myo-inositol-2-phosphate via a succinate diester linkage. The resulting conjugates were found to have dramatically enhanced water solubility relative to quercetin; the 5-linked quercetin analogue 2 had a water solubility of > 300 mg/mL at 20 degrees C. Comparison of the in vitro cytotoxicity and antiproliferative activity of conjugate 2 with those of quercetin toward cultured human colon adenocarcinoma (SW480) and human glioblastoma (U87MG) cells indicated that this modification of quercetin does not significantly diminish its activity in these assays.

Operation for atrial septal defect through a right anterolateral thoracotomy: current outcome

BACKGROUND

Operative closure of atrial septal defect is today considered a high-benefit and low-risk operation. Patients are often young and sensitive to the cosmetic results of the procedure. The midline scar of median sternotomy may be unsightly and can provoke dissatisfaction and psychological distress. For cosmetic reasons, an alternative operative approach, such as right anterolateral thoracotomy, can be proposed, with better aesthetic results and without increasing operative risks.

METHODS

Our study reviews retrospectively the long-term results of a consecutive series of 56 young patients in whom the atrial septal defect was closed through a right submammary approach. The indication for this approach was isolated atrial septal defect in female patients with complete development of the breasts.

RESULTS

In-hospital morbidity included three postpericardiotomy syndromes with one operative drainage for a moderate pericardial effusion (subxiphoid approach); 6 patients had supraventricular tachycardia in the early postoperative period. One patient presented with a symptomatic supraventricular arrhythmia and was treated medically for atrial flutter or fibrillation. Follow-up ranged from 12 to 240 months and included 41 of 57 patients. There were no early or late deaths. All patients were in normal sinus rhythm and free of symptoms, in New York Heart Association functional class I. Electrocardiography results showed 4 patients with first-degree atrioventricular block and 5 with complete right bundle branch block. Echocardiographic study results showed 3 patients with a trivial residual shunt. There were no other late complications. Breast volume and symmetry and the character of the scar were evaluated objectively by a physician and subjectively by a multiple-choice questionnaire completed by the same patients. The answers suggested that the patients' subjective impressions were at least commensurate with the objective findings. Most of the patients perceived the cosmetic results as good or excellent. No serious psychological problems related to the scar were found.

CONCLUSIONS

Right thoracotomy incision is a safe alternative approach to median sternotomy to repair isolated atrial septal defect in young female patients.

[Cardiac transplantation. Evaluation of a consecutive series of 75 grafts]

OBJECTIVES

The global results of various series of heart transplantation (HT) are essential to assess the life expectancy provided by this technique. Due to the increasing graft shortage, it appears essential to very strictly candidates for HT.

METHODS

From March 8, 1989 to December 7, 1994, 75 orthotopic Hts were performed in 62 men and 12 women (1 case of retransplantation). The mean age was 47.46 +/- 15.02 years (range: 2.5-66 years). Four patients were younger than 10 years and 22 were older than 60 years. Our series included more cases of ischaemic heart disease (36) than dilated cardiomyopathies (33), with a history of cardiac surgery in almost one quarter (20) of patients with ischaemic heart disease.

RESULTS

The immediate postoperative survival rate was 94.7% with 3 deaths attributable to refractory pulmonary hypertension associated with graft failure and one death related to postoperative tamponade. Five other patients died during the following 3 months, increasing the mean global survival to 88%. After a mean follow-up of 2.1 years (maximum 5.8 years), the actuarial 5-year survival rate was 56.8%. Eleven patients died between 4 and 38 months (mean: 18.2 months). Two deaths were due to cancers, 4 were due to septicaemia, another 4 were due to rejection and finally 1 was due to meningeal haemorrhage. The frequency (19) of reoperations for clot removal was due to the large number of patients with a history of previous heart surgery (20).

CONCLUSION

Strict recipient selection, possibly based on 123I-MIBG scintigraphy, the use of pulsatile circulatory assistance systems, improved CMV, morphometry and donor-recipient age matching, should optimize the results of a technique, whose efficacy is confirmed in this series.

[Value of percutaneous carotid angioplasty before cardiac surgery]

Transluminal angioplasty (TLA) of asymptomatic carotid stenoses (> 85%) in patients candidates for coronary artery bypass graft for stable angina appears to be an interesting technique to evaluate in a population whose management is controversial. Between January 1993 and January 1995, 10 patients underwent Carotid TLA (CTLA) prior to coronary artery bypass grafts (mean: 17.4 days). The mean age was 71 +/- 4.3 years. Eight patients were classified as NYHA class II and two were classified as class III. The mean number of bypass grafts per patient was 2.7. Four patients presented contralateral thrombosis of the internal carotid artery. CTLA was performed under cerebral protection by means of a triple coaxial catheter. Six CTLA required a Strecker stent. The mean follow-up was 11.4 months, with no mortality. One patient presented with transient hemianopsia. All patients were reviewed at 4 months by follow-up angiography, followed by Doppler. Only one of the 10 patients reviewed required redilatation with complementary stenting and another patient required dilatation of the stent. Although the follow-up of this short series is brief, the results of CTLA are encouraging in this population with a high risk of morbidity and mortality (elderly patients, frequently bilateral carotid lesions, coronary bypass grafts with multiple arterial grafts.

Aortopulmonary fistula: an uncommon complication in dystrophic aortic aneurysm

Wall dissection is a typical complication in the evolution of Marfan aortic aneurysm and usually is associated with valve regurgitation. Formation of a fistula with adjacent structures is very uncommon. We report the case of a 32-year-old man who presented with the typical features of Marfan's syndrome, with chronic aneurysm of the ascending aorta and acute aortopulmonary fistula. Diagnosis was made preoperatively by aortography; operation was performed successfully. A review of the literature only shows a few cases of aortopulmonary fistula in atherosclerotic, syphilitic, or postendocarditis disease.

Detection of elevated basic fibroblast growth factor during early hours of in vitro angiogenesis using a fast ELISA immunoassay

Basic FGF (bFGF) is a growth factor that is thought to play an important role in angiogenesis. Available assays that are used to detect bFGF are long and cumbersome. Here, we present a fast, easy and sensitive sandwich-type enzyme immunoassay for bFGF detection. Our method is a modification of the method described by Watanabe et al (Biochem. Biophys. Res. Commun. 1991; 175, 229). Two monoclonal antibodies for antigen capture and one noncongugated polyclonal antibody for antigen detection are used instead of using three monoclonal antibodies with the congugation of one of them for detection. There is no change in the sensitivity of the assay with average detection limit of 1 pg/well. Acidic fibroblast growth factor does not interfere with the assay. Using this method, samples from conditioned media of capillary endothelial cell culture before and after angiogenesis were measured. Associated with detection of start of tube formation, basic FGF was elevated at 8 hours from angiogenic stimulation and peaked at 48 hour (4 times control), showing for the first time in an in vitro system that there is a transient increase in endogenous bFGF accompanying early steps of angiogenesis which in turn may be the trigger for new capillary formation.

An animal model for the evaluation of graft thrombosis in the acute phase on carbon-lined PTFE prosthesis

Forty-five carbon-lined (CL) and 45 standard (ST) 4 mm internal diameter polytetra-fluoroethylene (PTFE) grafts were implanted as aortic interposition in 90 rabbits. A pilot study of 20 animals: 10 CL and 10 ST grafts were used to develop microsurgical techniques, then 60 grafts were placed in 60 New Zealand rabbits with lower morbidity. The two hours graft patency (Doppler and angiographic studies) showed better patency rate in CL group (93% versus 80%). In 10 animals, platelet accumulation was investigated in vivo using gammacamera imaging after injection of autologous platelets labeled with Indium111. In vitro, radioactivity counting of the explanted midgraft sections at 2 hours revealed 6 times greater activity in ST grafts (6.60 +/- 1.98 x 10(3) platelets/mm2 versus 0.82 +/- 0.25 x 10(3) platelets/mm2; p < 0.05). Light microscopy found platelet and fibrin deposition (PFD) in nearly all ST grafts whereas PFD were found in only 13% of the CL grafts corresponding to those thrombosed (chi 2: 61.117, p < 0.001). Carbon-lining decreases platelet accumulation on PTFE grafts in the acute phase of a new experimental model.

[Subacute rupture of the free wall of the heart. Clinical echocardiographic and pathological aspects apropos of 10 cases]

Three distinct forms of rupture of the heart may be identified after myocardial infarction: sudden rupture with massive intrapericardial haemorrhage, and sudden death with clinical signs of electromechanical dissociation; rupture into the pericardium resulting in a false aneurysm, the treatment of which is surgical; subacute rupture which accounts for 30% of cases in which bleeding into the pericardium is slow and/or repeated. Over an 8 year period and in a series of 2,400 consecutive infarcts admitted to the intensive care unit, 10 cases of subacute rupture of the heart were diagnosed. They were 6 men and 4 women, with a mean age of 73.6 years. The clinical presentation was isolated chest pain in 5 cases, syncope alone in 2 cases and the association of pain and syncope in 3 cases. Six patients were in shock on admission. In two cases, shock developed after admission. The infarction was confirmed biologically by a significant elevation of creatinine kinase in 9 out of 10 cases. Transmural infarction was observed in 9 cases: the infarct was electrocardiographically non-transmural in 1 case. Emergency echocardiography showed pericardial effusion in all cases, usually moderate, but sometimes compressive with an intrapericardial echogenic mass suggesting a thrombus. Haemodynamic improvement was obtained by medication allowing cardiac catheterisation which showed adiastole in 3 cases. Coronary angiography was performed in 7 cases. In 5 of the 7 cases, apart from occlusion of the artery presumed to be responsible for the infarct, the coronary vessels were diffusely infiltrated without significant stenosis. Left ventriculography was performed in 7 cases. In 6 of the 7 cases regional akinesis was demonstrated: the 7th case showed dyskinesia of the anterior wall. In two cases, contrast medium was observed to fill the pericardium during ventriculography, indicating myocardial rupture. The diagnosis of subacute rupture, suggested by clinical and paraclinical (particularly echocardiography), was confirmed in 9 cases at surgery and in the 10th case at autopsy. Surgery consisted of repairing the rupture. In the last two cases, biological glue was used to reinforce the surgical repair. The clinical outcome was good after surgery in 6 cases with a follow-up of 5 months to 8 years. The diagnosis of subacute rupture should therefore be made on clinical and echocardiographic criteria, as these results suggest that surgery is often possible, with a good prognosis.

[Value of the posterior route in the surgical treatment of popliteal aneurysm]

The authors report about 4 cases of surgical treatment of popliteal aneurysms through a strictly posterior approach. In all cases, the aneurysm was asymptomatic and diagnosed during the assessment of a controlateral symptomatic popliteal aneurysm that was treated in a conventional manner (exclusion and interposition of a femoropopliteal prosthetic tube through a medial approach). The procedure is carried out with the patient in ventral decubitus, and it consists in a debridement and graft with direct anatomical interposition of a straight PTFE tube. The posterior approach has limitations as it does not allow craniad extension and applies only to sacciform or short fusiform aneurysms the upper pole of which does not extend beyond Hunter's canal. The graft was an 8-mm PTFE straight tube in all 4 cases. All patients had a dynamic bilateral control angiography made and none of them presented with symptoms. Three conventional restorations required later embolectomy for thrombosis of the prosthesis. In our opinion, the use of the posterior approach for the surgery of popliteal aneurysm is appealing-provided strict criteria (aneurysm size, scheduled surgery, prosthesis) are complied with--as it reduces morbidity, restores the anatomical course and allows reducing the rate of postoperative thrombosis, thus ensuring better long-term patency.

Human saliva penetration of coronally unsealed obturated root canals

Studies have shown significant coronal dye and bacterial leakage following exposure of sealed root canals to artificial and natural saliva. The purpose of this study was to determine the time needed for bacteria in natural saliva to contaminate the entire length of root canals obturated by lateral and vertical condensation techniques. Forty root canals were cleaned and shaped using a step-back technique. Thirty root canals were obturated with gutta-percha and root canal sealer using either lateral or vertical condensation techniques. Forty root canals were obturated without a root canal sealer and served as positive controls. After obturation, the coronal 3 mm of five root canals were sealed with sticky wax and served as negative controls. The coronal portions of the filling materials were placed in contact with human saliva and the number of days required for bacteria in saliva to penetrate the entire root canals were determined. No bacterial leakage occurred in the negative control group. Complete bacterial leakage occurred within 2 days in the positive control group. All root canals were recontaminated in less than 30 days. No statistical significant difference was found between the two methods of obturation.

Sealing of human dentinal tubules by XeCl 308-nm excimer laser

Root hypersensitivity occurs as a result of exposed dentinal tubules. Various methods and materials have been tried in an attempt to occlude these tubules. The purpose of this investigation was to study by scanning electron microscope the effects of XeCl excimer laser on exposed dentinal tubules of human extracted teeth. Fifteen 3-mm-thick slices were cut at the cementoenamel junction from 15 extracted human teeth by an electric saw. By using a diamond bur to remove the cementum layer the dentinal tubules were exposed. Each slice was scored by a permanent marker into four equal quadrants. Three of the quadrants were lased for 4 s by XeCl excimer laser with fluences ranging from 0.5 to 7.0 J/cm2 and pulse repetition of 25 Hz. The unlased quadrant served as control. The specimens were mounted on a stub, sputter coated by gold, and examined by scanning electron microscope. Nonlased surfaces showed numerous exposed dentinal tubules. In contrast, all specimens lased at fluences of up to 1 J/cm2 showed the presence of melted dentin which closed the dentinal tubules. At fluences of 4 J/cm2 and higher, rupture of molten materials and exposure of dentinal tubules were noted. The results indicate the application of XeCl excimer laser at specific fluences can cause melting of dentin and closure of exposed dentinal tubules.

Effect of ArF-193 nm excimer laser on human dentinal tubules. A scanning electron microscopic study

The purpose of this study was to evaluate the effects of the ArF-193 nm excimer laser on the dentinal tubules of extracted human teeth under a scanning electron microscope. Fifteen 3 mm thick slices were cut with an electric saw at the cementoenamel junction from 15 extracted human teeth. A diamond bur was used to remove the cementum layer and expose the dentinal tubules. Each slice was scored by a permanent marker into four equal quadrants. The ArF excimer laser was applied for 5 seconds on three of the quadrants with fluences that ranged from 0.2 J/cm2 to 15 J/cm2 and pulse repetition of 25 Hz. The untouched quadrant served as a control. The specimens were mounted on stubs, sputter coated by gold, and examined by a scanning electron microscope. The effects of the ArF excimer laser irradiation varied. Laser fluences of 0.2, 0.5, and 1.0 J/cm2 had no effect. Although fluence of 15 J/cm2 caused significant removal of peritubular dentin, melting and resolidification of the dentinal smear layer was also observed under the scanning electron microscope with a laser fluence of 5 J/cm2.

Scanning electron microscopic study of the apical dentine surfaces lased with ND:YAG laser following apicectomy and retrofill

The purpose of this investigation was to study the effects of a Nd:YAG laser on the cut surface of teeth using scanning electron microscopy (SEM). Eighteen single-rooted teeth were cleaned, shaped, and obturated with gutta-percha and root canal sealer. The apical 3 mm of each tooth were resected with a diamond fissure bur, and the teeth were randomly divided into two groups of nine teeth each. The resected surface of each root in one group was lased twice. The duration of lasing and the number of pulses were recorded for each tooth. The teeth were air dried, mounted on stubs, sputter-coated with gold-palladium and examined under SEM. Application of the Nd:YAG laser caused melting of apical dentine surfaces. The melted material resembled the appearance of glazed interconnected droplets. Resolidification and recrystalization of the melted areas appeared to be incomplete and discontinuous. Some areas between the glazed regions appeared similar to those of non-lased apical dentine resected root surfaces.

Effects of Nd:YAG laser on apical seal of teeth after apicoectomy and retrofill

The application of Nd:YAG laser to tooth surface can change its surface permeability. The purpose of this study was to investigate the effects of Nd:YAG laser on the permeability of dentin following apicoectomy and retrofill. Sixty single-rooted teeth were randomly assigned to six groups of 10 teeth each. The six groups were arranged in three pairs, experimental and control groups. The canals of teeth in pairs 1 and 2 were cleaned, shaped, obturated, and their apical 2 mm were resected. A class I preparation was prepared and filled with amalgam in each tooth in pair 1. The apical 2 mm of each tooth in pair 3 was removed, and a class I preparation was prepared and filled with amalgam. The apical surface of resected roots in half of the samples in each pair was lased twice by using Nd:YAG laser. The duration of lasing and the number of pulses were recorded for each tooth. After application of nail polish to the unoperated surface of each tooth, the teeth were placed in 0.5% methylene blue dye for 48 h. The amount of dye penetration in sagittal sections of each tooth was measured. The amount of dye penetration was significantly lower in lased roots than in nonlased ones (p < 0.05). Based on our results, it appears that application of Nd:YAG laser reduces the permeability of resected roots.

[Echocardiographic aspects of multiple myxoma in Carney's syndrome]

In Carney's syndrome, the association of cardiac myxomas, spotty pigmentation and endocrine over activity, the myxomas are usually multiple and have atypical locations. The authors report a case in which an accurate diagnosis of these multiple myxomas was made by transoesophageal echocardiography, although transthoracic echocardiography had missed the diagnosis.

[Dissection of aorta after aortic valve replacement]

The authors report 4 cases of aortic dissection after aortic valve replacement. The aorta was dilated in all four cases before surgery. Two patients died within hours of the dissection, illustrating the poor prognosis of this complication and the difficulties of surgical management. The features of these four cases were compared to those of 29 other cases reported in the last ten years. The initial surgical indication for valve replacement was equally divided between aortic stenosis and regurgitation. The onset of dissection after surgery was very variable, ranging from a few hours to several years after valve replacement. Abnormalities of the aortic wall and peroperative trauma play an important role in the pathogenesis of this complication. The prognosis is very poor, which underlines the importance of preventive measures and regular follow-up of these patients.

[Late myocardial infarction after closure of coronary artery fistula]

Congenital coronary cardiac fistulae are rare conditions for which surgery is the usual indication. The authors report on the case of one female patient of 28 years with a coronary cardiac fistula responsible for exertional dyspnoea and relapsing pulmonary infections. The diagnosis was suggested by a continuous murmur and was confirmed by Doppler echocardiography and catheterization which showed a dilated, sinuous circumflex artery (2 cm) leading into the right atrium. Surgical closure of the fistula was complicated by an early myocardial infarction and a relapse in the same area with resulting mitral insufficiency. The surgical treatment of coronary cardiac fistulae is widely documented in the literature and recent series demonstrate that good results are usually obtained: however, a late infarction has not been described. The constitution of thrombi in the collateral vessels deriving from the distended vessel probably accounts for the particular evolution noted in this specific case.

Foetal and maternal distribution of inhaled mercury vapour in pregnant mice: influence of selenite and dithiocarbamates

The distribution of mercury after inhalation of metallic mercury vapour (6-8 mumols 203Hg0/kg b.wt.) was studied in pregnant mice (day 17 of gestation) after pretreatment with selenite (10 mumols Se/kg b.wt. intraperitoneally 1 hr before inhalation), thiram, disulfiram or diethyldithiocarbamate (1 mmol/kg orally 2 hr before inhalation of Hg0). For comparison, the effects of thiram, disulfiram and diethyldithiocarbamate on the distribution of mercury after administration of ionic mercury (7 mumols 203HgCl2/kg b.wt. intravenously) were also studied. Selenite pretreatment caused a longer retention of mercury in maternal tissues but decreased the foetal concentrations after 203Hg0 inhalation, similarly to what has been shown previously after administration of ionic mercury (Hg2+). Pretreatment with the three dithiocarbamates markedly increased the uptake in maternal brain and fat and decreased the foetal concentrations after intravenous injection of 203HgCl2. In contrast, no change in foetal uptake and only slight changes in maternal tissue concentration of mercury were observed after treatment with the dithiocarbamates followed by inhalation of 203Hg0, compared with 203Hg0 inhalation alone. The results are in favour of a firmer binding of mercury after Hg0 inhalation, when oxidation of Hg0 to Hg2+ occurs intracellularly, than after Hg2+ injection. Further studies, using repeatedly low dose administration of selenium, are needed to draw any conclusions concerning the protective effects of selenium after exposure to metallic mercury vapour.

Comparative embryotoxicity of selenite and selenate: uptake in murine embryonal and fetal tissues and effects on blastocysts and embryonic cells in vitro

The placental transfer and distribution pattern of selenium (Se) in embryonic and fetal tissues after intravenous injection of Na2(75)SeO3 (Se4+) or Na2(75)SeO4 (Se6+) has been investigated in mice in early, mid, and late pregnancy by use of whole-body autoradiography combined with gamma-counting. The given doses correspond to 45 micrograms Se/kg. In order to compare the direct toxicity in early embryonic stages, the two valence forms were studied by using in vitro systems with (1) mouse blastocysts and (2) chick embryo fibroblasts, differentiating into chondrocytes. The embryonic and fetal uptake after administration of Se4+ and Se6+ was almost identical. The placental transfer of Se was restricted but, nevertheless, increased with time after dosing and with progression from embryonic through fetal stages thereby suggesting active placental transfer. The highest uptake in the embryo was observed in the neuro-epithelium while the eye, liver and skeleton dominated the distribution pattern in the fetal period. Selenite (Se4+) was more toxic than selenate (Se6+) in the in vitro system, in which embryonic mesenchymal limb bud cells differentiated into chondrocytes, as well as in the blastocyst culture system. The results may suggest a direct effect of Se in the embryo as explanation to reported malformations in experimental studies.

[Cardiac sarcoidosis responsible for localized left ventricular ectasia and refractory ventricular tachycardia. Anatomoclinical study]

The authors report the case of a 63 year old woman admitted to hospital for recurrent refractory ventricular tachycardia. Echocardiography and cardiac scintigraphy showed global left ventricular function. Ventriculography confirmed the left ventricular dysfunction and also showed a localised aneurysm of the anterior left ventricular wall. Surgical resection of the aneurysm and an encircling endocardial ventriculotomy were performed but the patient died of a low output syndrome. Pathological examination of the excised tissue showed granulomatous lesions associated with fibrosis interrupting the striated myocardial bundles. The granulomata consisted in a large number of epithelioid histiocytes and very large giant cells with many nuclei. The diagnosis made retrospectively was that of cardiac sarcoidosis causing a ventricular aneurysm and global left ventricular dysfunction. The diagnosis of cardiac sarcoidosis is difficult in the absence of systemic extracardiac involvement because the clinical manifestations and complementary investigations are non specific. The diagnosis may be made by endomyocardial biopsy in 25 per cent of cases, thereby leading to specific treatment with steroids which is sometimes effective.

[Infectious endocarditis on native valves. Report of a series of 142 surgically treated cases]

The results obtained in a series of 142 patients operated upon, between December 1978 and December 1987, for infective endocarditis on native valve are reported. 61 patients (group 1) had acute progressive endocarditis and 81 patients (group 2) had subacute old-standing endocarditis. In group 1 patients, hospital mortality (i.e. occurring during the first 30 post-operative days) was 11.5 p. 100. During a mean follow-up period of 37.6 months (1.5 to 104.5 months), the survival rates were 52 p. 100 at 72 months and 37.4 p. 100 at 104.5 months. Mechanical desinsertion without persistence or relapse of the infective process, and recurrent endocarditis accounted for 27.8 p. 100 of deaths of known cause. Prognosis was better in group 2 patients. Hospital mortality was 4.9 p. 100, and during a mean follow-up period of 58 months (2 to 124 months) the survival rates were 84 p. 100 at 72 months and 73.4 p. 100 at 124 months. 60 p. 100 of late deaths of known cause were due to heart failure. In native valve infective endocarditis the post-operative diagnosis depends upon the pre-operative haemodynamic status, and the assessment of this status (notably with echocardiography) is a crucial element in the decision to operate.

[Heart surgery in 2 previously pneumonectomized patients]

Two cases of cardiac surgery under cardiopulmonary bypass in previously pneumonectomized patients are reported. In one case a postoperative tension pneumothorax required an emergency drainage. No other complications occurred. The authors describe their technique and underline the value of an adequate pre-operative respiratory preparation and a systematic drainage of the pleural cavity.

[Serologic and clinical study of post-transfusion viral contamination after cardiac surgery. Excluding human immunodeficiency virus]

The incidence of post-transfusion viral contamination after cardiac surgery is variable but not negligible. The serological and clinical features of such contamination were determined in a series of 100 consecutive patients seen between June, 1983 and January, 1984. The ELISA technique was used for hepatitis A and B viruses and cytomegalovirus on three samples of blood taken before (S1), and 15 days (S2) and 2 to 3 months (S3) after surgery. In case of hepatitis further investigations were performed for heterophilic infectious mononucleosis antibodies and for hepatitis B virus DNA. The transient appearance at S2 of anti-cytomegalovirus antibodies brought by transfusion was observed in 40% of the cases; seroconversion occurred in 4% (cytomegalovirus 3, hepatitis B virus 1), and 5% of the patients developed clinical and biochemical hepatitis without serological markers.

Elevated levels of 6-keto-prostaglandin-F1a from a lower extremity during external pneumatic compression

The synthesis of either fibrinolytic serine proteases or platelet inhibitory ecosonoids by the intact endothelial cell may limit thrombus development. In a preliminary study from this laboratory, an elevation in the level of 6-Keto-prostaglandin-F1å, the stable metabolite of prostacyclin (PGI2) was demonstrated in femoral vein plasma obtained during surgical treatment from an extremity undergoing external pneumatic compression. Simultaneously, no elevations in thromboxane B2, the stable metabolite of thromboxane A2, were observed. The present study is an inclusive prospective series of 26 patients. A single pneumatic compression stocking was applied to the left limb in patients who underwent an operation under general anesthesia. Base line venous samples (3 milliliters) were obtained from the femoral vein on the experimental side and the control contralateral side, as well as from the upper limb. Additional samples were drawn at 30 and 60 minutes after the onset of compression. Nine samples per patient (234 total) were analyzed for 6-Keto-prostaglandin-F1å by competitive binding radioimmunoassay in duplicate in a single blind manner. Base line values for the upper limb, right leg and left leg were 0.08 + 0.01 nanogram per milliliter; 0.14 + 0.03 nanogram per milliliter, and 0.13 + 0.02 nanogram per milliliter, respectively (no statistical difference). By 60 minutes of compression, control samples increased to 0.40 + 0.07 nanogram per milliliter (right leg) and 0.42 + 0.08 nanogram per milliliter (upper limb) while the experimental leg increased to 0.71 + 0.13 nanogram per milliliter (p less than 0.05 versus right leg, p less than 0.005 versus upper limb). There was no statistical difference at 60 minutes between the men and women.

Percutaneous balloon dilatation of calcific aortic valve stenosis: anatomical and haemodynamic evaluation

Two groups of elderly patients with calcified aortic stenosis were treated by balloon dilatation. In group 1, the valve was dilated just before surgical replacement of the valve. The valvar and annular changes occurring during dilatation were examined visually. In 20 of the 26 patients in this group there was no change. In the six remaining patients mobilisation of friable calcific deposits (1 case), slight tearing of the commissure (4 cases), or tearing of the aortic ring (1 case) were seen. Dilatation did not appear to alter valvar rigidity. In 14 patients (group 2) the haemodynamic gradient across the aortic valve was measured before and immediately after dilatation and one week after the procedure. Dilatation produced an immediate significant decrease of the aortic mean gradient and a significant increase of the aortic valve area. Eight days later the mean gradient had increased and the aortic valve area had decreased. Nevertheless there was a significant difference between the initial gradient and the gradient eight days after dilatation. The initial aortic valve area was also significantly larger than the area eight days after dilatation. The aortic valve gradient rose significantly in the eight days after dilatation and at follow up the gradients were those of severe aortic stenosis.

Endogenous plasminogen activator and venous flow: therapeutic implications

This study is concerned with the changes in endogenous plasminogen activator (PA), in response to the augmentation of venous blood flow by external pneumatic compression (EPC). EPC was applied to the left leg in ten patients undergoing surgery under general anesthesia. Two-ml samples of venous blood were obtained from the left and right femoral veins and an arm vein at baseline (induction), and then at 30 and 60 min of compression. Ninety samples were analyzed in duplicate in a single blind technique, using an assay specific for PA activity. In the control right arm and leg, PA activity levels increased at 30 min (106% and 110% of baseline, respectively), and then declined to baseline levels by 60 min. These changes did not reach statistical significance. In the leg undergoing compression, however, PA activity decreased progressively, reaching 75% of baseline at 60 min (significant at both 30 [p less than .001] and 60 min [p less than .01] as compared to baseline). In vitro, PA activity varies directly with the concentration of fibrin. The progressive decline in activity in this study may, therefore, represent a decline in substrate (molecular fibrin), as a result of increased venous blood flow. Alterations in the activity of the endothelial cell, as observed, may lead to new approaches in the prophylaxis against thromboembolism.

[Contribution of autologous blood transfusion in cardiac surgery in the adult]

The use of autologous blood transfusion in cardiac surgery is still controversial. This study was prospectively designed to evaluate the haemodynamic and haematological benefits of this method, with special attention to its impact on reducing bank blood requirements. Between November 1983 and October 1984, 160 patients underwent cardiac surgery with extracorporeal circulation and were randomly assigned to two groups: group I (81 patients) was the control group and group II (79 patients) received autologous transfusion following extracorporeal circulation. Blood was withdrawn immediately after the induction of anaesthesia via a jugular catheter and stored in CPD solution at room temperature. The volume of blood removed was replaced with gelatin solutions; after bypass, blood was returned to the patient. There was no difference in systolic, diastolic or mean blood pressures between the two groups. Right atrial pressure and heart rate were not statistically different in both groups. Myocardial perfusion and myocardial oxygen consumption remained unchanged in group II compared with group I. Complete haematological evaluation was carried out before and during bypass, and thereafter daily for the first twelve days of the postoperative period. There was no significative difference between the two groups in platelet counts, fibrinogen levels, prothrombin and partial thromboplastin times. During extracorporeal circulation, mean haematocrit was 22.9 +/- 0.4% in group II and 25.3 +/- 0.5% in group I (p less than 10(-3)). The mean haematocrit time course was similar in both groups during the postoperative period and returned to preoperative value at discharge.(ABSTRACT TRUNCATED AT 250 WORDS)