Immunological analyses of the chemotactic receptor of Dictyosteleum discoideum. Identification of cDNA clones

The cell surface cAMP receptor was excised from preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to generate a polyclonal antiserum. The antiserum immunoprecipitates the two molecular weight forms of the cAMP receptor. Both forms are phosphorylated. Western blot analyses show that the antiserum is highly specific and recognizes only the two molecular weight forms of the cAMP receptor. Immunological studies indicate that both forms of the receptor are phosphorylated. Vegetative amoebae possess low levels of the cAMP receptor. Levels of the antigen increase in differentiated cells which express high cell surface cAMP binding activity. The antiserum was also used to isolate 6 lambda gt11 cDNA clones. One of those clones contains a 1.1-kilobase pair cDNA fragment which encodes for a protein of approximately 30,000-35,000 daltons. The antibody which binds to the fusion protein also recognizes the two molecular weight forms of the receptor.

[Mechanical recanalization and dilatation of coronary arteries in the acute stage of myocardial infarction]

The time between coronary artery occlusion and reperfusion remains the decisive factor for myocardial function in acute myocardial infarction. Of 110 patients admitted to hospital less than 3 hours after the onset of chest pain, 83 underwent intracoronary thrombolysis with streptokinase or urokinase. 27 patients underwent mechanical recanalization with the aid of a steerable guide wire (Schneider 0.014") followed by transluminal angioplasty of the residual stenosis. 70 of 83 patients (84%) were recanalized by intracoronary streptokinase perfusion within 45 +/- 10 minutes. By mechanical recanalization the occluded artery could be recanalized in 27 patients within 6 +/- 1 minutes. During the same session transluminal angioplasty was performed while the affected coronary artery was perfused for 20 minutes with 20,000-50,000 U streptokinase. 2 patients died after intracoronary thrombolysis (2.4%) and 1 patient died after mechanical recanalization (3.7%). 25 of 26 survivors of the mechanical recanalization group were discharged after bicycle stress testing, and 1 patient underwent a coronary bypass operation. In the intracoronary thrombolysis group, 4 patients presented with reobstruction of the affected vessel within 24 hours of the intervention (4.8%). Of the remaining 66 patients. 20 underwent transluminal coronary angioplasty (285), 16 coronary bypass (22%) and 30 received drug therapy (43%). Left ventricular injection fraction, measured 24 hours after treatment, was 63 +/- 10% in the mechanical recanalization group and 53 +/- 9% in the intracoronary thrombolysis group.

[Outcome of coronary transluminal angioplasties followed by an occlusion]

Coronary occlusion is the most serious complication of percutaneous transluminal angioplasty. In 440 cases coronary occlusion occurred in 22 patients (5%). Treatment was coronary bypass in 12 cases mechanical recanalization in 7 cases and coronary bypass after unsuccessful mechanical recanalization in 3 cases. One patient died after mechanical recanalization and 9 (41%) had myocardial infarction confirmed by electrocardiography and angiography. The number of coronary occlusions increased initially but decreased with improvements in materials and techniques. It is concluded that coronary occlusion is a severe but rare complication of percutaneous angioplasty. Mechanical recanalization should be attempted, and in case of failure the patient should be referred for surgery. In the large majority of cases the outcome is benign.

[St Jude's Medical prosthesis in patients over 65]

Between September 1979 and December 1982, 56 St Jude Medical valvular prostheses were implanted in 54 patients over 65 years of age. Surgery consisted in simple aortic valve replacement (35 cases), simple mitral valve replacement (12 cases), double aortic and mitral valve replacement (2 cases), valve replacement and coronary artery bypass surgery (3 cases), aortic valve replacement and replacement of the ascending aorta (1 case) and mitral valve replacement and tricuspid annuloplasty (1 case). The operative mortality (within 30 days of surgery) was 3.5% (2 cases). Patients were assessed by clinical examination, ECG, chest X-ray, echocardiogram and laboratory investigations on average 19 months after surgery. There were 3 late deaths (1 endocarditis, 1 cardiac failure and 1 subdural haematoma). No cases of significant haemolysis were observed. There were no cases of thrombosis of the valve or any deaths directly related to the valve. Four patients had cerebral embolism (4.9% per patient/year). None were fatal and only 1 patient had sequellae. Clinical improvement was very significant; 96% of the patients are now in the NYHA Classes I and II whilst 80% were in Class III or IV before surgery. The cardiothoracic ratio decreased significantly from 0.56 to 0.51 (p less than 0.01). The authors conclude that elderly patients may derive great benefits from valvular cardiac surgery and that age in itself is not a contraindication to this type of surgery. The St Jude Medical prosthesis is an excellent prosthesis but thromboembolism remains a major problem as with other mechanical prostheses. Anticoagulation for life is essential.

[The artificial St. Jude valve: clinical course and complications recorded in 155 patients]

The St. Jude Medical cardiac valve is a low-profile, bileaflet, central-flow prosthesis made of pyrolitic carbon. During a 39-month period (October 1, 1979 to December 31, 1982) a total of 169 St. Jude valves were implanted in 155 patients. While 141 patients received one valve, 95 in the aortic, 45 in the mitral and 1 in the tricuspid position, 14 patients had a double (aortic and mitral) valve replacement. The perioperative mortality rate was 3.2%. All surviving patients had anticoagulation treatment with acenocoumarol and there was a 98% follow-up during a period of 19.5 +/- 4.5 months. The late mortality rate was 4.7%. Substantial clinical improvement resulted with the St. Jude valve: whereas 81.9% of patients were in NYHA functional class III or IV preoperatively, 87.1% were in class I or II after valve replacement. The patients generally had a slight increase in LDH levels but hemolysis was responsible for moderate anemia only in 5 cases. There were 10 nonfatal neurological accidents, probably due to thromboembolic events, resulting in a risk of thromboembolism of 4.04% per patient year; 4 of the 10 patients were incompletely anticoagulated and 3 had cardiac arrhythmia. There were 5 hemorrhagic complications, one of which was fatal (subarachnoidal hemorrhage). Endocarditis occurred in 4 patients and death ensued in one of these. Seven patients developed perivalvular leak which was moderate in 5 cases and severe in 2 cases. In conclusion, these results are promising and the St. Jude Medical cardiac valve appears to be a valid alternative in surgical therapy of valvular heart disease. However, the risk of thromboembolism justifies long-term anticoagulation.

[Dissection of the aorta following cardiac surgery]

With the growing number of cardiopulmonary by-pass operations, ascending aortodissection, as a complication of surgery, is increasing. The clinical picture is somewhat complex; five typical cases are described. With early diagnosis and correct treatment, survival is possible even when the prognosis is not good. This complication is best avoided by prevention at the time of surgery.

[Left ventricular function following revascularization for occlusion of a coronary artery lasting 1 to 2 hours]

The time-lag between coronary occlusion and irreversible damage to the myocardium is ill-defined in man. In 10 patients the changes in left ventricular function have been studied after coronary occlusion during diagnostic or therapeutic cardiac catheterization of 1-2 hours' duration. Revascularization was achieved either surgically or through intracoronary streptokinase infusion. The interval between occlusion and onset of extracorporal circulation or reopening was 61 to 119 minutes. Despite enzyme elevation (CPK, CK-MB, SGOT) and appearance of Q-waves in 5 patients, no significant alteration of left ventricular function was noted on repeat cardiac catheterization 10 to 230 days after the accident. These observations, suggest that coronary occlusion of 1-2 hours' duration fails to produce significant irreversible damage to the myocardium despite electrocardiographic and enzymatic signs of myocardial infarction.

[Intracoronary thrombolysis as a treatment for evolving myocardial infarction]

Myocardial infarction is almost always the consequence of a thrombotic obstruction of one or more coronary arteries. We report our experience with the first 24 cases of intracoronary thrombolysis for recanalization of obstructed coronary arteries. 19 cases were successful, 1 case was partially successful and in 4 instances no reopening was observed. The amount of streptokinase used was 206 000 +/- 107 000 units, and reperfusion was achieved after 37 +/- 27.5 minutes. Recanalization of the vessel was accompanied by cessation of precordial pain and partial or complete normalization of the electrocardiogram. In one case bypass surgery was necessary because of reocclusion. Left ventricular function improvement after thrombolysis was dependent on the time-lag between occlusion and recanalization. These observations confirm others' experience that intracoronary thrombolysis appears to have favorable effects in patients with evolving myocardial infarction.

[Heart metastasis, possibilities of surgical treatment? Apropos of 2 cases]

The pathological aspects of cardiac metastases are nowadays well known, but, whatever the treatment proposed, their clinical evolution is usually disappointing. Two cases of cardiac metastases are reported, one from carcinoma of the uterine cervix and one from a costal chondrosarcoma. Both patients died soon after surgical excision of heart metastases. It seems that whatever the treatment elected (chemotherapy, radiotherapy, or cardiac surgery), the patient with a cardiac metastasis dies on the average within the year of the diagnosis. This poor prognosis makes it important to select the appropriate mode of therapy, probably with a rather restrictive approach to the use of heart surgery in this situation.

Iatrogenic myocardial infarction. A possible complication of mitral valve surgery related to anatomical variation of the circumflex coronary artery

Following mitral valve replacement, a 43-year-old male presented electrocardiographic signs of myocardial ischemia-injury in the postero-inferior wall, and subsequently died. The post mortem examination revealed a subendocardial myocardial infarction in the postero-inferior wall. The myocardial infarction was related to the accidental ligation of the circumflex coronary artery by one of the sutures fixing the prosthetic valve. Technically, this surgical accident can be explained by the anomalous origin and course of the circumflex coronary artery found in this patient at the time of the post mortem examination. Anatomical variations of the coronary arteries and their surgical implications are discussed. This iatrogenic complication could have been avoided by performing a preoperative coronary angiography, which was not done in the reported case for medical reasons.

[Evaluation of aortic dissection by transverse computerized tomography (CT scan)]

Twenty patients with dissection of the thoracic aorta were studied by CT-scanning. In 9 patients the diagnosis was previously documented by aortography, while in the other 11 patients the diagnosis of aortic dissection was first established by CT-scanning. The latter demonstrated the characteristic signs of aortic dissection and particularly the following features: a) the false channel (95%) and the intimal flap (90%), b) the displacement of aortic wall calcifications (60%), especially when the false channel is partially thrombosed (80%). In 19 patients, a bolus injection of contrast medium was performed. In the majority of cases opacification of the false channel occurred only partially, with some delay and with a non-homogeneous pattern. Six out of the 20 patients underwent one or more follow-up examinations performed between 15 days and 2 years later. CT-scanning clearly demonstrated the late persistence of a patent false channel and particularly the delayed thrombosis, even after surgical treatment of aortic dissection. CT-scanning appears to be a reliable non-invasive method for - establishing the diagnosis of aortic dissection, - delineating the extent of dissection, - follow-up of evolution after surgical or medical therapy.

Improvement of left ventricular function after percutaneous transluminal coronary angioplasty

Cardiac function and left ventricular dynamics were measured in seven consecutive patients 1 day before and 6 months after percutaneous transluminal balloon angioplasty of subtotal proximal stenosis of the left anterior descending coronary artery. Before angioplasty all patients had obvious left ventricular dysfunction during exercise and to a smaller degree during isoproterenol infusion; the condition of all patients was greatly improved 6 months after angioplasty. After angioplasty, left ventricular end-diastolic pressure was normal at rest and decreased from a mean (+/- standard error of the mean) of 33.8 +/- 1.6 to 19.2 +/- 0.5 mm Hg on exercise. Left ventricular ejection fraction, measured by a gated blood pooling technique with technetium-99m, improved on exercise from 46 +/- 5.0 percent to 69 +/- 1.0 percent. Cardiac output and stroke volume index increased significantly with exercise after angioplasty. The peak negative rate of pressure reduction in the left ventricle (dP/dt/min), an index of left ventricular relaxation, was highly abnormal on exercise before (2,307 +/- 260 mm Hg/s) and increased to the normal range (3,154 +/- 200 mm Hg/s) after angioplasty. The improvement in left ventricular function after transluminal angioplasty in these cases of proximal left anterior descending coronary arterial stenosis is extremely encouraging.

[Reintervention for recurrent angina pectoris after aortocoronary bypass]

In this department between 1969 and 1980, 1116 angina patients underwent aorto-coronary venous bypass operation for revascularization of the myocardium. Thirty-four (3%) of these patients later underwent reoperation for anginal recurrence. Recurrence of angina was due principally to obstruction of an aorto-coronary venous bypass graft (48.6%) and progression of atheromatous disease in non-grafted coronary arteries. 9% of reoperated patients had a myocardial infarction postoperatively. Overall mortality was 6%. Quality of life must be considered excellent when it is observed that 87% of these patients enjoyed symptomatic improvement and as many as 63% were still asymptomatic following an average observation period of more than three years (38.7 months). On the basis of these encouraging results, all patients with recurrence of angina should undergo further coronary investigations with a view to reoperation.

[Severity of stabilized angina pectoris and indication for coronary bypass-implications for prognosis]

The prognosis in patients with mild or moderate angina pectoris (class I or I-II) and significant coronary artery lesions (70% or more luminal diameter reduction) is controversial. Since 1967 these cases have not been operated upon in our Division. To assess the justice of this approach, 61 mildly symptomatic, non-operated patients (group I) were compared with 65 markedly symptomatic (class II to IV) patients in whom coronary artery bypass procedures were indicated but not performed (group II). These patients either had refused surgery or the lesions were considered unsuited to revascularization. Although 44 patients in group I had 70% or more stenosis of one or more coronary arteries, the 8-year mortality rate in group I was 17% compared with 40% in group II. For patients with single vessel disease (32 patients in group I, 35 patients in group II) the 8-year mortality was 9.4% in group I and 34% in group II; the difference is significant. This retrospective study suggests that mild and moderate angina pectoris (class I or I-II with or without medical treatment) is associated with a rather favourable prognosis (one single death during the first four years in group I). It may be concluded that an aggressive approach can be delayed until further symptoms develop despite adequate medical therapy.

[Surgical treatment of associated coronary disease and heart valve disease]

25 patients underwent combined surgery for coronary artery and valvular heart disease. Although patients suffering from associated coronary artery and valvular lesions represent a high operative risk group, the combined surgical procedure is clearly justified by the functional improvement of the patients. Selective coronaro-angiography should be carried out in the assessment of patients over 40 years of age with valvular disease, since not all patients present angina in spite of diseased coronary arteries. Three hospital deaths (13.5%) indicate the gravity of the procedure, but the absence of intra- or postoperative myocardial infarction and the comparatively rapid recovery of the patients with relatively few complications are very encouraging.

An attempt to separate xiphopagus twins sharing a common heart, liver, and duodenum

An attempt was made to separate 7-wk-old conjoined twins. It proved unsuccessful because of extensive cardiac malformations in the shared heart. Details of operation and postmortem findings are described.