Allelic association at the D14S43 locus in early onset Alzheimer's disease. French Alzheimer's Disease Collaborative Study Group

The D14S43 marker is closely linked to the major gene for early onset autosomal dominant Alzheimer's disease on chromosome 14. Allelic frequencies at the D14S43 locus were compared in 113 familial and isolated cases of early onset Alzheimer's disease (< 60 years of age at onset) (EOAD) and 109 unaffected individuals of the same geographic origin. Allele 7 was significantly (P = 0.033) more frequent in type 1 EOAD patients (13.2%), defined by the presence of at least another first degree relative with EOAD, than in controls (4.1%). Since an autosomal dominant gene is probably responsible for type 1 patients, allelic association may reflect linkage disequilibrium at the D14S43 locus. This would mean that some patients share a common ancestral mutation. However, since multiple tests were carried out, this result must be interpreted with caution, and needs confirmation in an independent sample.

[Fibrinolytic inhibitors and prevention of bleeding in cardiac valve surgery. Comparison of tranexamic acid and high dose aprotinin]

In order to assess the effects of tranexamic acid in comparison to the high dose regimen of aprotinin recommended by Royston and considered to be the reference in postoperative bleeding in cardiac surgery, 35 consecutive patients were randomised to two groups according to the product prescribed. The global postoperative bleeding was comparable in the two groups (p = 0.49). One surgical reoperation for haemostasis was required in the reference group. There was one case of renal failure in the same group due to cardiac failure. No thrombotic complications were observed. Platelet function, as judged by the bleeding time and platelet aggregation to ristocetin, was the same in the two groups. The D-dimers remained low in both groups, reflecting the absence of intravascular coagulation and fibrinolysis. Tranexamic acid was as effective and as safe as high dose aprotinin. These two substances, in addition to their fibrinolytic inhibitory activity, conserved platelet protection by blocking the action of plasmin. These results seem to justify the preventive use of tranexamic acid from the moment of skin incision, especially in reoperation.

[Effect of antisense oligonucleotides on myo-intimal hyperplasia in a model of abdominal aortic injury in the rat]

Restenosis at a rate > 30% at 6 months is the major complication of both coronary and peripheral arterial angioplasty. Restenosis is mainly due to proliferation of smooth muscle cells, extracellular matrix and collagen which form a neointima. The proto-oncogene c-myb is a gene with an immediate response which has been implicated in the proliferation and alteration of the phenotype of smooth muscle cells. The antisenses are molecules of single-helix DNA the sequence of which is inverse to that of messenger RNA of the target proto-oncogene. They therefore have the possibility of forming a double helix with the messenger RNA and of preventing its translation. The antisenses of c-myb have already been successfully tested in in vitro and in vivo models of neointimal proliferation. The aim of this study was to demonstrate the efficacy of c-myb antisenses on the proliferation of smooth muscle cells in a model of abdominal aortic injury in the rat. Thirty-five male Wistar rats with an average weight of 350 grams were operated. Smooth muscle cell proliferation was obtained by desendothelialisation of the abdominal aorta from the level of the left renal vein to the aortic bifurcation. Using a randomised, double-blind protocol, 17 rats were given 500 microliters of pluronic gel (control group), 9 a sense oligonucleotide of c-myb in 500 microliters of pluronic gel (sense group) and 9 a c-myb antisense oligonucleide in 500 microliters of pluronic gel (antisense group). Two rats were given fluorescinlabelled antisenses; one was sacrificed 4 hours and the other 24 hours later.(ABSTRACT TRUNCATED AT 250 WORDS)

Technique of homograft replacement of the mitral valve

In this paper, we have reviewed previous experiences in the technique of homograft replacement of the mitral valve. Following laboratory studies, we have initiated a clinical program of partial and total homograft replacement of the mitral valve and present our early results in the first 32 patients.

Twitch analysis as an approach to motor unit activation during electrical stimulation

The mechanical twitch in response to increasing electrical stimulus intensity, delivered both over the motor point and motor nerve, was recorded in the first dorsal interosseous (FDI) and the adductor pollicis (AP), and only over the motor point in the soleus (Sol), lateral (LG), and medial (MG) gastrocnemius muscles of human subjects. The relationship between intensity of electrical stimulation (ES) and twitch torque showed a positive linear regression in all muscles. In the FDI and AP the relationship was not significantly different when ES was applied at the motor point or over the motor nerve. At small intensities of activation, ES induced larger twitch torques in the MG and LG, which contain a roughly equal proportion of slow and fast motor units (MUs) compared to the Sol, which is composed mainly of slow type fibres. Moreover, the relationship between ES intensity and twitch time-to-peak is best fitted in all muscles by a power curve that shows a greater twitch time-to-peak range in its initial part for muscles containing a larger proportion of fast MUs (LG, MG) than for muscles mainly composed of slow MUs (Sol). In conclusion, these results induced by ES at the motor point and/or over the motor nerve confirm the concept of a reversed sequence of MU activation, as compared to voluntary contractions, and document this viewpoint in muscles of different function and composition. The reversed sequence of MU activation is more clearly evident during motor point ES.

[Training of surgeons for laboratory research]

A degree in surgical research has been set up in 1986 in France. It includes a one-year full time work in a research laboratory, and seminars (one to three days long, each). General surgical research objectives are gathered in a first seminar. Then, candidates select one among four optional subjects: biomaterials-artificial organs, transplantation, oncology, and neurosciences. Two prerequisites are necessary in order to register. The first is to write a research project according to standardized rules, and the second is to attend two seminars, one dealing with scientific communication and the other with methodology in clinical research. A nation-wide valid Academic degree is delivered to candidates who pass an oral presentation of their research report and who attended all seminars according to the optional subject that they selected. From 1986 to 1993, 434 students attended the formation. They came from different regions of France, proving the nation-wide characteristic of the degree, and some from foreign countries. Seminars were held in different French University towns. An increasing number of students become Ph.D.

Double mitral homograft for recurrent bacterial endocarditis of the mitral and tricuspid valves

A young patient suffering from acute bacterial endocarditis underwent reconstructive surgery of the mitral and tricuspid valves. One year later a recurrent endocarditis occurred that could not be controlled with antibiotic therapy. Two separate mitral homografts were used to replace both the mitral and the tricuspid valves. The homografts' papillary muscles were sutured side to side to the recipient's and a circumferential suture of the leaflet tissue was accomplished. Homograft implantation was associated with Carpentier ring annuloplasty of the atrioventricular valves. In the right sided position, the mitral homograft was oriented in an anti-anatomical manner and an inverted semi-rigid prosthetic ring of the mitral type was inserted. Clinical and echocardiographic follow up at four months was excellent.

Myocardial neutrophil sequestration and activation related to the reperfusion of human heart during coronary artery surgery

OBJECTIVE

The aim was to determine if neutrophils are activated and sequestered as they pass through postischaemic human myocardium.

METHODS

The occurrence of neutrophil activation during the reperfusion of the ischaemic myocardium was investigated in 16 selected patients undergoing coronary artery bypass surgery. Neutrophils were counted and elastase and lactoferrin released into the plasma were measured simultaneously in myocardial venous blood and in peripheral venous blood, before aortic cross clamping (T0), and two (T1), 10 (T2), and 20 (T3) min after unclamping.

RESULTS

At T0, no statistically significant difference was noted between peripheral and myocardial blood with respect to the three variables studied. Reperfusion was associated with a significantly lower neutrophil count in myocardial blood compared to peripheral blood (p < 0.001), suggesting that neutrophils were trapped within the myocardium during reperfusion. In addition, levels of elastase (T1, T2, and T3), and lactoferrin (T1) were significantly higher in myocardial blood as compared to peripheral blood (p < 0.001), suggesting that activated neutrophils released their granular content into the plasma milieu.

CONCLUSION

We provide evidence consistent with local neutrophil activation during myocardial reperfusion in patients undergoing coronary artery bypass surgery, in addition to the well described systemic activation related to cardiopulmonary bypass.

Postoperative pseudoaneurysm of ascending aorta: role of ultrafast computed tomography imaging

A 34-year-old woman, who had undergone a thoracic aortic aneurysmectomy and replacement with a prosthetic tube graft several months previously, presented with a pseudoaneurysm arising from the proximal anastomotic site. This pseudoaneurysm was studied with contrast-enhanced ultrasfast computed tomography. The exact location of the suture dehiscence was located by the presence of a contrast jet flow through the aortic wall. This case shows the feasibility of demonstrating blood flow at the entry site of a pseudoaneurysm with ultrafast computed tomography which may avoid conventional angiography.

Peripheral vascular involvement in heart transplant patients

Between 1984 and 1991 a total of 200 patients underwent heart transplantation in our unit. The records of 121 patients who were followed up for more than 1 year were reviewed for peripheral vascular abnormalities, which were found in 12 (9.9%). Most of these patients underwent transplantation for ischemic heart disease, and peripheral vascular disease preceded the heart transplantation in 80%. Although surgical risks are low in this setting, particular caution should be exercised to prevent septic complications in the femoral triangle. Among the risk factors studied, only elevated blood cholesterol was frequently found in the vascular patients before or after transplantation. Peripheral vascular involvement in heart transplant patients corresponds to the natural course of atheroma rather than to an accelerated process of atherosclerosis.

Combined coronary and femoral revascularization using an ascending aorta to bifemoral bypass

OBJECTIVE

Coronary artery and aortoiliac disease frequently coexist. In rare instances simultaneous procedures may be required. This study reports our experience with ascending aorta to bifemoral bypass.

DESIGN

Prospective consecutive sample study.

PATIENTS

Ten male patients who underwent concomitant aortoiliac and coronary revascularization with the ascending aorta as the source of inflow to the femoral arteries between 1989 and 1991.

RESULTS

One hospital death was unrelated to the surgical technique. All survivors displayed an uneventful recovery and were free of symptoms. Follow-up was obtained in all nine cases, they all stayed asymptomatic in terms of coronary artery disease and peripheral vascular disease. Echo-doppler studies showed perfect patency of the aorto-femoral grafts in all cases.

CONCLUSIONS

This study shows that the ascending aorta to bifemoral bypass constitutes an interesting alternative in selected cases mainly those with severe ischemia coronary and leg ischemia. It offers the following advantages: (1) it is easy to perform, (2) does not require an intraperitoneal procedure, (3) the graft's position behind the muscles of the abdominal wall is not compressible, (4) the ascending aorta is the source of inflow, and (5) it allows a shorter duration of hospital stay.

[Mitral valve replacement with cryopreserved mitral homograft]

Mitral valve replacement using a cryopreserved mitral homograft was performed in a 49 year old patient with calcified mitral stenosis. The surgical technique is described. The postoperative course was uneventful. Transoesophageal echo performed 4 months later showed a normal function of the mitral homograft.

[Comparative vasoreactivity of the radial, internal mammary and gastroepiploic arteries. Implications in coronary surgery]

Recently, satisfactory results were obtained in a series of patients in whom the radial artery was used as a conduit for coronary artery bypass. However, spasm of this conduit was observed in four percent of patients. The aim of this study was to analyze the vasoreactive properties of the radial artery and to compare them to those of the internal mammary and the gastroepiploic arteries. Human radial (56 from n = 15 patients), internal mammary (77 from n = 20 patients) and gastroepiploic (41 from n = 12 patients) arteries ring segments were mounted on a strain gauge in oxygenated, normothermic, Krebs solution at optimal resting tension. With potassium chloride (100 mM) serving as the control, the dose response curves to norepinephrine, serotonin and thromboxane A2 mimetic were obtained, hence permitting to assess force of contraction and sensitivity. Functional endothelium was assessed by acetylcholine. Smooth muscle-dependent relaxation was assessed by sodium nitroprusside. The radial artery had stronger contractions to potassium chloride than the other vessels. The radial and the gastroepiploic arteries with endothelium presented a higher contraction force than the internal mammary artery in response to norepinephrine and serotonin. The gastroepiploic artery had a lower sensitivity to thromboxane A2 mimetic compared to the two other vessels. This increased reactivity of the radial artery explains its propensity to spasm and emphasizes the need for antispastic drugs and platelet inhibitors when the radial artery is used for coronary artery bypass.

Heparin-induced thrombocytopenia and thrombosis following open heart surgery

We recently observed five cases of early thrombus formation in patients undergoing anticoagulation with subcutaneous heparin following open heart surgery. The reasons prompting surgery were as follows: one mitral valve replacement, one double valve replacement, one mitral valve reconstruction, one aortic valve replacement associated with coronary bypass. In all cases, intravenous heparin was begun on the day of surgery and replaced by subcutaneous (SC) heparin on postoperative day 1. Acute thrombocytopenia was observed between the 6th and 11th postoperative day. This was interpreted as denoting an idiosyncratic reaction to heparin which was replaced by low molecular weight heparin (LMWH) in two cases and by acenocoumarol in the other cases. Massive thrombosis of the aortic valve resulted in the death of one patient. Thrombosis of the left atrium occurred in three patients (two of whom had a transient ischemic attack (TIA)). One patient had aorto-iliac thrombosis. Successful reoperation was carried out in four of the five patients. Although heparin-induced thrombocytopenia and thrombosis [HITT] is a rare complication of heparin therapy, serial platelet count monitoring and in vitro platelet aggregation tests are mandatory in the diagnosis of this syndrome. Discontinuation of heparin is indicated as soon as the syndrome is recognized and the institution of aspirin is recommended if the thromboembolic complication requires reoperation and reexposure to heparin.

[Use of the radial artery for coronary artery bypass. A new experience after 20 years]

Twenty years after its first introduction by A. Carpentier, the use of the radial artery (RA) for coronary bypass was reinvestigated because of unexpected good long term results in some patients. Since July 1989, 158 patients (pts) underwent myocardial revascularization using 189 RA grafts (31 pts received 2 grafts). The left internal mammary artery (LIMA) was concomitantly used as a pedicled graft in 151 cases and the right internal mammary artery (RIMA) in 31 cases, a free IMA graft was used in 29 cases and a saphenous vein graft in 40 cases. A mean of 2.8 graft/pt was performed. The target artery receiving the RA was: circumflex (n = 93), diagonal (n = 39), right coronary (n = 47) and LAD (n = 10). Two patients died (1.3%) and three presented a perioperative myocardial infarct (2.5%). Sternal wound infection was noted in three cases of double IMA implant. No ischemia of the hand was observed. All patients received diltiazem started intraoperatively and continued after discharge. In addition, aspirin (100 mg/day) was given at discharge. Early angiographic controls (< 3 weeks) were obtained in the first 60 consecutive patients and revealed: 73/73 patent RA grafts, 58/58 patent LIMA grafts, 16/16 patent RIMA grafts, 15/19 patent free IMA grafts and 10/11 patent vein grafts. Six patients presented a localized narrowing of the RA conduit unrelated to the anastomotic lines (spasm). Late angiographic control (6 to 24 months) was obtained after a mean follow-up of 11 months in 37 patients: 42/46 RA grafts were patent (91.3%) and free of spasm and 4 were occluded.(ABSTRACT TRUNCATED AT 250 WORDS)

Criteria for anatomical compatibility of the total artificial heart: computerized three-dimensional modeling of the cardiovascular anatomy

A quantitative study of cardiovascular anatomy was performed by obtaining three-dimensional reconstructions from regular computed tomography scan images in 15 patients, all candidates for heart transplantation. Volumetric estimates of the cardiovascular structures were obtained from these three-dimensional reconstructions using data directly related to total artificial heart (TAH) implantations. By using computerized three-dimensional modeling of these structures, reproducible measurements of the parameters defining the shape and the anatomical connections of the intrathoracic space available for TAH implantation could be derived. The results are intended to be used for both technical and clinical applications such as computer-assisted drawing of the pericardial cavity and the anatomical connections (useful for improving the design of TAH) and combined statistical calculations (multiple regressions, cluster algorithm) of the measurement results, which will then enable the best selection to be made among two or three TAH models for each patient.

Three-dimensional modeling of the anatomy of the heart and great vessels

The anatomic constraints imposed on a total artificial heart (TAH) require specific anatomic studies. A thoracic anatomic study was performed with a scanning device equipped with three-dimensional (3-D) reconstruction software on 15 male patients, between the ages of 41 to 63 years (52 +/- 6 years). All were candidates for heart transplantation. The 3-D reconstructions of the cardiovascular structures obtained from surgical anatomy data specific to TAH implantation allowed a volumetric measurement of these structures. A modeling diagram of these structures permitted reproducible quantitative measurements of the 35 geometrical parameters which characterized shape, orientation, and position of these structures within the thorax. Most of the measured parameters were characterized by low variability (coefficient of variation from 10 to 25%).

Vasoreactivity of the radial artery. Comparison with the internal mammary and gastroepiploic arteries with implications for coronary artery surgery

BACKGROUND

Recently, satisfactory results were obtained in a series of patients in whom the radial artery was used as a conduit for coronary artery bypass. However, spasm of this conduit was observed in 4% of patients. The aim of this study was to analyze the vasoreactive properties of the radial artery and to compare them with those of the internal mammary and the gastroepiploic arteries.

METHODS AND RESULTS

Human radial (56 from 15 patients), internal mammary (77 from 20 patients), and gastroepiploic (41 from 12 patients) artery ring segments were mounted on a strain gauge in oxygenated, normothermic Krebs' solution at optimal resting tension. With KCl (100 mM) serving as the control, the dose-response curves to norepinephrine, serotonin, and thromboxane A2 mimetic were obtained, permitting assessment of force of contraction and sensitivity. Functional endothelium was assessed with acetylcholine. Smooth muscle-dependent relaxation was assessed with sodium nitroprusside. The radial artery had stronger contractions to KCl than the other vessels. The radial and the gastroepiploic arteries with endothelium presented a higher contraction force than the internal mammary artery in response to norepinephrine and serotonin. The three vessels had equal sensitivities to norepinephrine and serotonin. The gastroepiploic artery had a lower sensitivity to thromboxane A2 mimetic than the two other vessels.

CONCLUSIONS

This increased reactivity of the radial artery explains its propensity to spasm and emphasizes the need for antispastic drugs and platelet inhibitors when the radial artery is used for coronary artery bypass.

Transposition of chordae in mitral valve repair. Mid-term results

BACKGROUND

Prolapse of the anterior mitral leaflet, unlike a posterior prolapse, is a difficult lesion to repair. Leaflet plication and triangular resection are satisfactory techniques only in case of a limited prolapse. Chordal replacement has also been proposed but uses foreign material. The purpose of this report is to assess the results of transposition of chordae for the correction of mitral regurgitation (MR) caused by anterior leaflet prolapse.

METHODS AND RESULTS

Between January 1986 and December 1990, 44 adult patients with MR caused by anterior leaflet prolapse underwent repair with transposition of chordae as one of the techniques. This population was retrospectively studied to assess the early and late results of this procedure. Chordae were transferred from the posterior to the anterior leaflet (n = 25) or from an intermediary to a free edge position on the anterior leaflet (n = 21) (two patients underwent both procedures). Two patients died (4.5%). None required early reoperation. Follow-up was complete and ranged from 18 to 82 months (mean, 40.2 +/- 19 months). No patient died during follow-up. Two patients were reoperated on 6 and 8 months after surgery for recurrent MR unrelated to chordal transfer disruption. Doppler echocardiographic studies were available in 95% of the cases at latest follow-up and showed no or minimal MR (0 to 1/4) in 87.5% of the patients and mild MR (2/4) in 12.5%.

CONCLUSIONS

Transposition of chordae appeared to be a simple and safe procedure for correction of anterior mitral prolapse. Transposition of chordae allowed extension of the indications of valve repair. A longer follow-up will be necessary to draw firm conclusions, but mid-term results are encouraging.

[Combined surgery of the mitral valve and the abdominal aorta in a case of Takayasu's disease]

The authors report the case of a 34-year-old woman, of North African origin, with mitral valve disease and abdominal aortitis. The differential diagnosis between Takayasu' disease, embolism of cardiac origin and rheumatic aortitis is discussed. Treatment of these lesions was by combined cardiac and vascular surgery in a single-stage operation.