MIG in autoimmune thyroiditis: review of the literature

The monokine induced by interferon (IFN)-γ (MIG) and its receptor, the chemokine (C-X-C motif) receptor (CXCR)3, appear to contribute to the pathogenesis of autoimmune thyroiditis (AT). MIG is secreted by thyrocytes under the influence of IFN-γ. In tissue, recruited Th1 lymphocytes may be responsible for enhanced IFN-γ, which in turn stimulates MIG secretion from thyrocytes creating an amplification feedback loop, and perpetuating the autoimmune process. Circulating MIG and IFN-inducible T-cell α chemoattractant (I-TAC) levels are increased in patients with thyroiditis and hypothyroidism and are related to each other. The importance of a Th1 immune attack in the initiation of AT has been demonstrated. MIG levels were significantly higher in elder patients, or in those with a hypoechoic ultrasonographic pattern, or with hypothyroidism. In peripheral fluids, high MIG levels are considered a marker of host immune response, in particular Th1 orientated T-cells. Other studies are needed to continue to investigate the role of MIG as a novel therapeutic target in AT.

[Diagnostic and prognostic significance of CK-MB, troponins, CRP, BNP and/or NT-proBNP in coronary angioplasty. Elevation mechanisms and clinical implications]

The recommendations from respected bodies concerning the treatment and follow up of patients undergoing coronary angioplasty for stable angina or acute coronary syndrome (ACS) are essential for reducing the risks related to the procedure, and for preventing the occurrence of long term complications. Measuring the levels of troponin and CK-MB is part of the diagnostic and prognostic strategy during the coronary angioplasty procedure. In this context, the frequent elevation of markers following uncomplicated angioplasty is a sign of minor irreversible myocardial damage, the prognostic significance of which remains under discussion. Recent data suggest that only a basal troponin elevation (more so than CK-MB) prior to angioplasty has a long term prognostic value in ACS ST- patients, and that troponin elevation occurring after the procedure in the presence of normal basal concentrations, is only associated with in-hospital complications. Determining the basal level of troponin would appear to be essential for interpreting any elevation in concentrations following angioplasty. The recommendations should integrate this fundamental point, if it is confirmed. On the other hand, the question has been raised whether other markers (CRP, BNP and/or NT-proBNP) should be systematically measured as a routine prior to angioplasty. An elevation of CRP before and/or after angioplasty is an unfavourable short and long term prognostic factor. Elevation of NT-proBNP before angioplasty is also an unfavourable long term prognostic factor. Recommending a multi-marker strategy might represent a future direction for identifying at risk patients prior to coronary angioplasty, thus enabling specific treatment to be proposed.

[Angioplasty of intra-stent restenosis of a saphenous graft complicated by massive embolism]

The main risk of angioplasty of saphenous vein aortocoronary bypass grafts is myocardial infarction by distal embolism, explaining the introduction of systems of distal protection with encouraging results. Although embolism of an atheromatous stenosis is classical, that of intra-stent restenosis is exceptional. The authors report a very unusual case of atheromatous and/or thrombotic embolism occurring during angioplasty of an intra-stent restenosis which was recovered by a micropore filter system.

[Prognostic value of normal coronary angiography]

Coronary angiography is the "gold standard" for coronary artery disease (CAD). It is considered either normal or subnormal without any lesion (endocoronary echography often demonstrates atheroma), or in presence of a < 50% stenosis. Nevertheless, the risk of plaque rupture is not well correlated with the degree stenosis. Despite the frequent presence of non-significant atheroma, is a normal coronarography really of a good prognosis? Between January and September 1997, 136 of 600 (22.6%) angiographies were considered as normal. The indications were: "CAD suspicion" (n = 77), "preoperative angiography of valvulopathy" (n = 38), and "angioplasty control" (n = 22). The arteries were strictly normal for 86 patients (63%) and a < 50% stenosis was found in 50 patients (37%); 108 patients (80.1%) were followed for 18 +/- 3 months: eight non coronary deaths were reported: four postoperative deaths in "valvular group", two pulmonary embolisms and two pulmonary neoplasm's in "CAD suspicion group". No myocardial infarction was reported and one unstable angina was documented. Despite the frequency of non-significant atheroma, an acute coronary syndrome exceptionally complicates a "normal" coronarography.

Questionable thymic nurse cell

Since their discovery in 1980, thymic nurse cells (TNCs) have been controversial. Questions pertaining to the existence of the TNC as a "unit" cell with thymocytes completely enclosed within its cytoplasm were the focus of initial debates. Early skeptics proposed the multicellular complex to be an artifact of the procedures used to isolate TNCs from the thymus. Since that time, TNCs have been found in fish, frogs, tadpoles, chickens, sheep, pigs, rats, mice, and humans. Their evolutionary conservation throughout the animal kingdom relieved most speculations about the existence of TNCs and at the same time demonstrated their apparent importance to the thymus and T-cell development. In this review we will discuss and debate reports that describe (i) the organization or structure of TNCs, (ii) the thymocyte subset(s) found within the cytoplasm of TNCs and their uptake and release, and (iii) the function of this fascinating multicellular interaction that occurs during the process of T-cell development. Discussions about the future of the field and experimental approaches that will lead to answers to remaining questions are also presented.

Circulating macrophages as well as developing thymocytes are enclosed within thymic nurse cells

Both thymic nurse cells (TNCs) and macrophages have been reported to function as antigen-presenting cells during the process of MHC restriction. Negative selection, which results in the apoptosis of potentially autoreactive thymocytes, is believed to be associated with both macrophages and TNCs in the cortex. Both cell types have also been reported to ingest thymocytes undergoing positive and negative selection. However, macrophages ingest apoptotic thymocytes, while TNCs have been shown to internalize viable cells. A subset of the TNC-engulfed population is allowed to mature and is released, while the remaining fraction becomes apoptotic and is absorbed within the TNC cytoplasm through lysosomal activity. A recent report described a subset of rat TNCs that contain macrophages as well as thymocytes within their cytoplasm. We examined freshly isolated TNCs from C57BL/6 mice and found that, of the TNC population recovered, 1.7% contained macrophages within its cytoplasm. There also were macrophages tightly bound but not internalized into the multicellular structure at a rate of 2.9%. The total association of macrophages with TNCs was approximately 4.6%. This unique association of macrophages with TNCs was also observed in vitro when freshly isolated thymocytes (containing macrophages) were added to cultures of cells from the TNC cell line tsTNC-1. The macrophage-TNC interaction was found to be dynamic, with macrophages moving rapidly into and out of TNCs containing cytoplasmic thymocytes. Macrophages within TNCs showed a close association with cytoplasmic thymocytes. We then labeled peritoneal macrophages with CFDA SE, a cell tracking dye, and returned them to the mouse peritoneum. Within 1 h, labeled macrophages were detectable in the thymus. This is the first investigation to show a direct interaction between peripheral macrophages and TNCs. These results suggest that TNCs and macrophages work together as antigen-presenting cells.

TNF and Fas-induced apoptosis during negative selection in thymic nurse cells

Apoptosis of thymocytes associated with thymic nurse cells (TNCs) has been well-documented. TNCs selectively bind and internalize immature alphabeta TCRlo CD4+ CD8+ thymocytes in vitro. A subset of the internalized population matures to the alphabeta TCRhi CD69hi stage of development while the fraction that remains within the cytoplasm dies through the process of apoptosis. Negative selection by thymic cortical epithelial cells has been reported, but little is known about the apoptotic pathway(s) employed to facilitate the death signal. Using the TNC line tsTNC-1 that was reported earlier to maintain the ability to internalize alphabeta TCRlo CD4+ CD8+ cells in vitro, we investigated the role of Fas and TNFalpha in TNC-induced apoptosis. Our initial studies revealed that tsTNC-1 cells express both FasL and TNFalpha apoptosis of triple positive cells was shown to be reduced approximately 50% in co-cultures of tsTNC-1 cells and thymocytes in the presence of either anti-TNFalpha or Fas-Fc. When maximum effective concentrations of both TNFalpha, and Fas-Fc were added to these co-cultures, apoptotic death was further reduced to approximately 68%. These results suggest that both TNFalpha and Fas apoptotic pathways are active during thymocyte selection by TNCs.

A single point mutation in HIV-1 V3 loop alters the immunogenic properties of rgp120

The results of the study presented in this report show that clones of env derived from genetically divergent HIV-1 field isolates fall into two major subsets based on the predicted secondary structure of the V3 region in gp120. One subset exemplified by the clones A-UG06c, B-RT3.12 and C-UG045 is predicted to assume a beta-turn conformation in the V3 loop and comprises the GPGX residues. The other subset exemplified by the clones D-UG23c and D-UG042 (GXGX) are deficient in the expression of the beta-turn in the loop. Since secondary conformations are highly likely to confer antigenic properties in a protein backbone at least for B cells, we have used nucleic acid immunization to test the effect of the beta-turn deficiency on the immunogenic potential of rgp120 encoded in these field isolates. As hypothesized, inoculation of BALB/c mice with the env plasmid encoding the beta-turn expressing rgp120 molecules resulted in the development of a vigorous antibody response to the homologous V3 loop peptides. In contrast, immunization with an rgp120 clone deficient in the beta-turn in the V3 loop showed no evidence of antibody development to the V3 loop. Instead, the latter clones triggered T cell proliferative responses and markedly increased the level of IL-2 and IFN-gamma production by T cells. Significantly, reconstitution of the beta-turn conformation by site-directed mutagenesis of a single V3 loop residue yielded rgp120 molecules which restored antibody production while diminishing the cell-mediated immune (CMI) responses to the V3 residue. These observations demonstrate the marked impact of a single amino acid substitution on the immunogenic properties of V3 region in gp120 encoded by divergent HIV-1 field isolates.

[Hemostasis disturbances in myocardial ischemia]

In this article, a description has been given of the close connection between coronary atherosclerosis and the onset of thrombosis. The hemostatic factors examined in this study are implicated both in the pathology of acute coronary syndromes and in the prognosis of ischemic heart disease. Amongst other factors, the role of the following has been investigated: platelets, thromboxane A2 and prostacyclin, von Willebrand factor, factor VII and tissue factor, thrombin, fibrinogen tissue plasminogen activator and plasminogen activator inhibitor. It is concluded that endothelial dysfunction in coronary atherosclerosis is the most frequent cause of disturbances in hemostatic function.

Subxiphoid pericardiocentesis guided by contrast two-dimensional echocardiography in cardiac tamponade: experience of 110 consecutive patients

AIMS

We evaluated echo-guided pericardiocentesis with contrast study in cardiac tamponade management.

PATIENTS AND METHODS

From 1982 to 1998 we performed pericardiocentesis in 110 patients (56 +/- 14 years old). Subxiphoid approach was used in 109. Cardiac tamponade was idiopathic (n = 16), secondary to malignant disease (n = 50) and miscellaneous disorders (n = 44).

RESULTS

Pericardial fluid was bloody (n=75), serous (n = 29) or turbid (n = 6). Mean volume of fluid removed was 585 +/- 370 ml. When prolonged drainage (60 +/- 26 h) was used (n = 41), total effusion volume was 850 +/- 340 ml. Eleven deaths were observed during the early period following pericardiocentesis. No relation with procedure was demonstrated by autopsy in 10, and death always occurred in critically-ill patients (five malignant diseases, five cardiac ruptures and one septic shock). Other complications were: right ventricular puncture (n = 11) with deleterious effect in one, vasovagal hypotension (n = 6) and paroxysmal arrhythmia (n = 6). Surgical drainage was mandatory in 19 patients. It had to be done as an emergency (within 6 h), because of failure of the procedure in four patients. In 14 patients without prolonged drainage a delayed surgical evacuation was indicated, because of persistent (n = 3) or recurrent (n = 11) cardiac tamponade. Only one surgical procedure was required after prolonged drainage.

CONCLUSIONS

Echo-guided pericardiocentesis with contrast study is an effective technique which reduces the risk of cardiac tamponade management. It should be considered in patients with critical haemodynamic condition or advanced malignancy, and in patients with poor short-term prognosis.

[Aneurysm of the sinus of Valsalva. Apropos of a case of right intra-atrial rupture]

An unusual systolo-diastolic heart murmur was discovered fortuitously in a 39-year-old man undergoing a routine check-up. Transesophageal echocardiography gave the diagnosis of Valsalva sinus aneurysm ruptured into the right atrium. Cardiac surgery was successful. We reviewed the literature on this unusual condition, focusing on the pathophysiological, clinical, diagnostic and therapeutic aspects. Transesophageal echocardiography provides the diagnosis.

[Cardiac tamponade]

Cardiac tamponade is an emergency situation. Diagnosis is to be suspected when an elevation of systemic venous pressure, a decline in systemic arterial pressure and a clinical context of neoplasia or recent acute pericarditis are associated. Transthoracic echocardiogram is the gold-standard of diagnosis, and allows the accurate diagnosis of a large pericardial effusion: precise localisation and haemodynamic evaluation are needed before therapeutic decision. Pericardiocentesis is the only appropriate treatment. Surgical procedure, or less traumatic echo-guided pericardiocentesis, provide rapid haemodynamic relief of symptoms. Prognosis is determined by aetiology.

[Immediate collateral coronary circulation after a methylergometrin test]

The development of a collateral coronary circulation has been well studied by angiography in two main clinical situations: myocardial infarction (by durable coronary occlusion) and angina (due to significant coronary artery stenosis), but only rarely in spastic angina. The authors report the case of severe spasm at the site of non-significant stenosis after a methylergometrine test, with immediate contro-lateral collateral circulation in a patient with a short history of spastic angina without myocardial infarction. This observation demonstrates that collateral circulation may develop very rapidly in spastic angina (without basal ischaemia in the absence of significant coronary stenosis), because this patient only had seven ten-minute episodes of clinical ischaemia. As collateral circulation may mask clinical and electrical signs in spastic angina, this case suggests that angiographic control should be systematic during the methylergometrine test.

Lysosomal-mediated degradation of apoptotic thymocytes within thymic nurse cells

A thymic epithelial cell line (tsTNC-1) that maintains the ability to selectively bind and internalize immature alphabetaTCR(lo)CD4(+)CD8(+) thymocytes in vitro was used in long-term coincubation experiments to determine the ultimate fate of thymocytes that remained within intracytoplasmic vacuoles of thymic nurse cells (TNCs). In an earlier report, a subset of the population released from the TNC interaction was shown to mature to the alphabetaTCR(hi)CD69(hi) stage of development, while thymocytes that bided within the TNC cytoplasm died through the process of apoptosis. Here, we show the presence of both apoptotic and nonapoptotic thymocytes within the cytoplasm of freshly isolated TNCs as well as in tsTNC-1 cells in culture. A microscopic analysis revealed total degradation of the cytoplasmic apoptotic thymocyte population that remained in tsTNC-1 cells after an 8- to 10-h incubation period. A quantitative analysis showed an increase of cytoplasmic thymocyte degradation over time to almost 80% after 9 h of incubation. However, in the presence of bafilomycin A1, which is used to inhibit acidification of lysosomal vesicles, degradation of apoptotic thymocytes never reached 10%. These data suggest that lysosomes within TNCs play a role in the degradation of apoptotic thymocytes. We examined tsTNC-1 cells before the addition of thymocytes to cultures and found lysosomes to be clustered around the nucleus in the cytoplasm of TNCs. Shortly after the internalization event, apoptotic thymocytes move to the area of the cytoplasm containing lysosomes. Using the confocal microscope, we obtained evidence that shows the degradation event to be facilitated through the fusion of lysosomes with the specialized vacuoles within TNCs containing apoptotic cells.

[Thoracic radiodermatitis in interventional cardiology. Apropos of 6 cases]

The aim of this study is to describe thoracic radiodermatitis, a rare but not to be forgotten complication of interventional cardiology. The appearances are variable, from often oval-shaped erythema to cutaneous necrosis, with risk of chronic ulceration and malignant degeneration. The authors report 6 cases observed in 1997 after coronary angioplasty. Complex and long procedures are the main causes of this complication. Prevention requires a contribution from all the medical cardiological team, for the diagnosis, determining the indication of the type of revascularisation and for limiting the dose of X-radiation administered.

Feasibility of routine transradial coronary angiography: a single operator's experience

The aims of this study were to assess the feasibility of routine transradial coronary angiography in a standard population of patients with presumed coronary artery disease over a period of time long enough to allow for technical evolution and evaluation of a single operator's learning curve, and to provide data for a randomized comparison versus the femoral approach. Between June 1994 and March 1997, transradial angiography was attempted in 1,000 patients. Approximately 25% of these patients were excluded because of an abnormal Allen test. Except in the case of acute myocardial infarction, there was no selection based on symptoms, age, sex, weight or size in the absence of double internal mammary artery bypass graft operation or simultaneous right heart catheterization. Symptoms and angiographic results were typical of a standard population. The right radial approach was used in 95% of the cases for ease of handling and comfort of a right-handed operator. Radial artery puncture and catheterization success was obtained in 97.6% of the cases; the left coronary artery was selectively catheterized in 100%, right coronary artery in 98%, left ventricle in 96.9%, mammary artery grafts in 100% and saphenous grafts in 97.2%. Average procedure duration was 18 +/- 9 minutes, and decreased progressively with experience and catheter strategies. The optimal catheter selection would seem to be a single catheter, either left Amplatz or Champ, for both coronary arteries. Two coronary complications and 3 transient neurological complications occurred, but no clinically significant vascular complications requiring surgery or transfusion were reported. Transradial angiography seems to be a routine approach that should now be compared with the femoral approach and supersede the brachial approach whenever possible.

A thymic nurse cell-specific monoclonal antibody

A thymic epithelial cell line (tsTNC-1) that maintains the ability to selectively bind and internalize immature alpha beta TCRloCD4+CD8+ thymocytes in vitro was used in the development of a monoclonal antibody that is specific to the cell surface of thymic nurse cells (TNCs) in the thymus. The rat monoclonal antibody ph91 showed specificity to cells of the subcapsular region of the thymic cortex. Upon mechanical dispersion of the thymus in vitro, ph91 recognized cells displaying the multicellular morphology unique to TNCs. Ph91 staining was not detected on fresh thymocytes, stromal cells of the inner thymic cortex, thymic medullary cells, B cells or fibroblasts. Ph91 recognized a 43-kDa protein on the surface of TNCs. Exposure of tsTNC-1 cells to ph91 in tissue culture significantly reduced the percentage of binding of the alpha beta TCRloCD4+CD8+ thymocyte subset previously shown to target TNCs. In organ culture, ph91 reduced the viability of developing thymocytes by 70%. The largest reduction was found in the alpha beta TCR+CD4+CD8+ thymocyte subset. These results represent the first report of a TNC-specific monoclonal antibody. Further, the antigen to which ph91 binds may play a role in the process of thymocyte binding and their subsequent internalization which is unique to TNCs and important to the T cell developmental process.

[Tamponade in patients with systolic left ventricular dysfunction. An atypical presentation]

BACKGROUND

Left ventricular failure has been described following surgery due to localized compression of the left ventricle and in case of diastolic left ventricular dysfunction after pericardiotomy or pericardiocentesis.

CASE REPORTS

Global heart failure was observed in 3 patients with dilated cardiopathy who developed tamponade. Systolic left ventricular dysfunction was caused by ischemic heart disease in one patient and secondary to anthracyclin chemotherapy in the two others. The effusion was successfully removed with pericardiocentesis in all three cases. No specific complications were observed.

DISCUSSION

Although exceptional, tamponade may occur in patients with signs of left ventricular failure.

[Coronary angiography by a radial artery approach: feasibility, learning curve. One operator's experience]

The aim of this study was to assess the feasibility of the radial artery approach for coronary angiography in a standard population of presumed coronary patients and to continue the assessment for a sufficiently long period of time to perfect the technique, evaluate the learning curve and prepare a randomised comparison with the femoral approach. The radial artery was used for coronary angiography in 800 patients after exclusion of about 25% of patients, mainly because of a negative Allen's maneuver. With the exception of acute myocardial infarction, there was no selection based on symptoms and transradial catheterisation was attempted irrespective of age, sex, weight or height. The representative nature of the study population was confirmed by the results of the procedure (normal: 20%, single vessel disease: 30%, double vessel disease: 26%, triple vessel disease: 18% and left main disease: 5.4%). The right radial artery was used in 94% of cases. Successful radial puncture/catheterisation was obtained in 97% of cases: 100% of left coronary arteries and 99% of right coronary arteries were catheterised, the left ventricle in 98% of cases, the internal mammary arteries in 100%, and venous bypass grafts in 95%. The average duration of the whole procedure was 19 +/- 9 minutes. This decreased regularly with operator experience and judicious choice of catheters. The best choice seemed to be a single catheter for both coronary arteries, either an Amplatz or a Champ catheter. There were two probably avoidable coronary complications and two transient neurological events but no clinically significant vascular complication. The radial artery seemed to be a good approach for routine coronary angiography and may now be compared with the femoral approach. It should help expand the practice of ambulatory coronary angiography.

[Evaluation of echo-guided pericardiocentesis in cardiac tamponade]

Between April 1982 and December 1995, 78 consecutive patients with an average age of 57 +/- 13 years underwent echo-guided pericardiocentesis in the intensive care unit for poorly tolerated pericardial effusions. The patients were admitted to the cardiology departments of Ambroise-Paré Hospital at Boulogne (n = 44). Gilles-de-Corbeil Hospital at Corbeil-Essonnes (n = 31) and Val-de-Grâce Hospital in Paris (n = 3). The underlying aetiologies were malignant disease (n = 31), idiopathic (n = 13), post-surgery (n = 7), infection (n = 7), autoimmune (n = 6), post-radiotherapy (n = 6), post-myocardial infarction (n = 3), chronic renal failure (n = 3) and coagulation defects (n = 2). Pericardial puncture was undertaken by the subxiphoid (n = 77) or left parasternal (n = 1) approaches under guidance of echocardiography. Intra-pericardial contrast was used to verify the position of the catheter. The average volume of liquid drained was 580 +/- 390 mL. After pericardiocentesis, continuous drainage was continued in 17 patients for an average duration of 63 +/- 29 hours. The total average volume was 750 +/- 330 mL. The major complications were a) three deaths during the puncture, not caused by the procedure after post-mortem study, b) ten right ventricular punctures with no consequences in 9 cases, c) two cases of shock, one of which was due to a pre-existing septicaemia of pulmonary origin, d) two non-sustained ventricular arrhythmias. The minor incidents were six vasovagal syndromes during the procedure and four paroxysmal supraventricular arrhythmias. Emergency surgical drainage was required (n = 3) for a failed procedure and late surgical drainage (n = 12) for persistence or recurrence of the effusion. No surgical drainage was required in the 17 patients placed under continuous aspiration. Echo-guided pericardiocentesis is a simple procedure and provides rapid haemodynamic relief in subjects generally in serious condition. Continuous aspiration may help avoid the need for surgical drainage for persistence or recurrence of the effusion.

[Ultrasound-guided pericardial drainage. Experience in 34 consecutive patients]

OBJECTIVES

Transthoracic echoguided puncture of the pericardium can be an alternative to surgical drainage. We report our experience with this technique acquired over the last 11 years.

PATIENTS AND METHODS

From January 1984 to September 1995, 34 consecutive patients in the cardiology intensive care unit (mean age 56.5 +/- 13 years) underwent echoguided pericardial puncture for poorly tolerated pericardial effusion. The underlying cause was neoplasia (n = 22), idiopathic disease (n = 5), autoimmune disease (n = 2), post-surgical complication (n = 2 including 1 on hemodialysis), infection (n = 1), antivitamin K therapy (n = 1) and disseminated vascular coagulation (n = 1). The subxyphoid (n = 33) or left parasternal (n = 1) route was used under echographic guidance. Intrapericardial contrast allowed verification of the catheter position. The mean quantity of fluid removed was 585 +/- 390 ml. The fluid was hemorrhagic (n = 19), clear (n = 10) or serohematic (n = 4). Aspiration was continued in 16 patients after the initial puncture for a mean 64 hours. The mean total volume of fluid was 750 +/- 330 ml.

RESULTS

There was one death during puncture which was found to be unrelated to the procedure after anatomic verification. In two cases, the left ventride was punctured without any consequence. Collapsus occurred during puncture in 2 patients with pulmonary sepsis. Minor incidents were: 6 vasovagal syndromes at puncture with paroxysmal supraventricular rhythm disorder during aspiration. Prior to 1988, surgical drainage was required in 5 patients for persistent or recurrent effusion. Since that time, continuous aspiration has been used in all patients and no surgical drainage has been required. Short-term prognosis depends on the underlying cause (6 deaths at 1 month).

CONCLUSION

Echoguided pericardial puncture is a simple procedure which rapidly improves cardiac hemodynamics in these particularly fracle patients. Continuous aspiration avoids subsequent surgical drainage for persistent or recurrent effusion.

Positive selection by thymic nurse cells requires IL-1 beta and is associated with an increased Bcl-2 expression

A temperature-sensitive line of thymic nurse cells (tsTNC-1) that maintains the ability to selectively internalize immature alpha beta TCRloCD4+CD8+ thymocytes in vitro was used in long-term coincubation experiments to determine nurse cell function during the process of MHC restriction. The thymocyte subset released from its association with TNCs contained both viable and apoptotic cells. The cells that remained within intracytoplasmic vacuoles died through the process of programmed cell death. Surviving or rescued thymocytes in the released population displayed an increase in Bcl-2 protein expression. The rescue activity of TNCs was drastically reduced with the addition of antibodies against either class I or class II MHC antigens to cocultures. A subset of the TNC-rescued population matured from the alpha beta TCRloCD69- phenotype to alpha beta TCRhiCD(69+)-expressing cells only when IL-1 beta was added to cocultures. These results suggest that TNC rescue of early double-positive thymocytes from apoptosis is associated with an interaction between the TCR and the MHC and the onset of Bcl-2 expression. Maturation of thymocytes within the TNC-rescued population requires the costimulatory effects of IL-1 beta.

[Spontaneous intracardiac contrast and embolic risk]

Spontaneous contrast in the form of smokey echos in the cardiac chambers is considered to be a risk factor for thromboembolism. The aggregation of red blood cells results in larger target which diffuse a measurable in vitro ultrasonic signal. The phenomenon of erythrocytic aggregation is dependent on the red cells themselves, the plasma fibrinogen and conditions of blood flow. The other constituents of the blood only reflect a small amount of ultrasound, usually undetectable. Transoesophageal echocardiography with high frequency transducers (5 MHz) positioned in close proximity to the cardiac chambers, has become the reference method for detecting spontaneous contrast. This phenomenon is almost exclusively observed in the left atrium and left auricle and rarely in the other cardiac chambers or descending aorta. In pathological situations, spontaneous contrast is essentially implicated in two conditions: mitral valve obstacles and non-valvular atrial fibrillation. Conversely, moderate to severe mitral regurgitation is a negative predictive factor of spontaneous contrast. However, a purely qualitative appreciation of spontaneous contrast which may be influenced by the gain setting and technical specifications of the echocardiograph, and the subjectivity of the operator, is an important limitation. Therefore, the identification of quantitative markers of spontaneous contrats and new therapeutic antithrombotic protocols remain essential.

Thymic nurse cell rescue of early CD4+CD8+ thymocytes from apoptosis

We have now developed temperature sensitive lines of thymic nurse cells (TNCs), using the SV40 viral mutant tsA58, that maintain the ability to selectively internalize a subpopulation of alpha beta TCR+CD4+CD8+ thymocytes in vitro. One line, tsTNC-1, was shown to be able to rescue a subset of CD4+CD8+ thymocytes from programmed cell death at 32 degrees C, the temperature at which binding and internalization were detected. Rescue was significantly diminished at 38 degrees C, the temperature at which thymocyte binding was not observed. The rescued population of thymocytes showed a reduced level of apoptosis as measured by the DNA fragmentation assay. TNC rescue resulted in a shift of CD4+CD8+ thymocytes from immature TCRlow PNArhigh cells to the more mature TCRint PNArlow phenotype but no changes in cell surface levels of HSA nor CD69 were detected. The rescue activity of tsTNC-1 cells at 32 degrees C was significantly reduced with the addition of antibodies to either class I or class II MHC antigens. These results suggest that we have established TNC lines, using the SV40 viral mutant tsA58, that have the ability to rescue a subset of the TNC interactive thymocyte population from programmed cell death. The thymocyte population rescued by TNCs matures to a phenotype within the double positive stage of development that is indicative of positive selection.

[Transesophageal echography and left intraventricular echo-contrast. Complete regression of a large thrombus of the left ventricle with anticoagulant therapy]

The authors report the case of a 69 year old man with a large left ventricular thrombosis complicating anterior myocardial infarction occurring three years previously for which anticoagulant therapy had to be withdrawn. The discussion is based around the large size of the thrombus, its complete regression with anticoagulant therapy (heparin and coumarin-derivative) and also around the detection of spontaneous echo contrast in the left ventricle by transoesophageal echocardiography. This case underlines the probable risk of withdrawing anticoagulant therapy in patients with severe left ventricular dysfunction and left ventricular spontaneous contrast.

[Reperfusion arrhythmia]

Reperfusion arrhythmias were described from the first trials of intracoronary thrombolysis for myocardial infarction. The prevalence of ventricular fibrillation during intravenous thrombolysis is low (< 7%) and comparable to that observed with classical treatment. Holter recording shows that ventricular tachycardia and accelerated idioventricular rhythms occur in over 80% of cases. These arrhythmias are generally well tolerated and do not require specific therapy. A bradycardia-hypotension syndrome is observed in about a quarter of reperfused patients, nearly always in inferior wall infarction. It normally resolves spontaneously or after atropine or vascular filling. Reperfusion is associated with a clearcut increase in the number of episodes of arrhythmia. Some arrhythmias such as sustained ventricular tachycardia, early accelerated idioventricular rhythms (occurring in the first 6 hours) or the bradycardia-hypotension syndrome may be considered as non-invasive criteria of reperfusion. More severe ischemia and sudden reperfusion favour the arrhythmogenicity of reperfusion in the animal. Recent data suggest that this may be the case in the clinical context. In some uncontrolled studies, lidocaine, betablockers and aspirin did not affect the prevalence of the arrhythmias. Preliminary trials indicate that flunarizine and captopril may reduce the incidence of reperfusion arrhythmias in man. Ventricular arrhythmias and myocardial stunning could be the result of sa single phenomenon (the extent of the ischemic lesions or reperfusion lesions). Studies currently under way should clarify the relationship between the incidence of arrhythmias, the severity of stunning and myocardial recovery. Protocols evaluating therapeutic interventions on the reperfusate should include Holter monitoring.

The binding, internalization, and release of thymocytes by thymic nurse cells

Recent studies in our laboratory have described the development of the SV40-transformed thymic nurse cell (TNC) line SVT-II2, that maintains the ability to internalize thymocytes in vitro. SVT-II2 cells were shown to bind and internalize a subset of the alpha beta TCR+, CD4+CD8+ thymocyte population exclusively. Also, SVT-II2 cells express cell surface class I and class II MHC antigens. These data are consistent with reports that suggest that TNCs may have a role in thymic education. In this report, we used scanning electron microscopy, transmission electron microscopy, and long-term video microscopy to study binding, internalization, and release of thymocytes by TNCs. The results of these experiments showed the internalization event to be selective and dynamic. The process appears to involve programmed cooperation between the two cell types that terminates with the release of selected thymocytes. Although no changes in thymocyte cell surface phenotype were detected as a result of their interaction with TNCs in vitro, over 90% remained viable after a 48-hr incubation period.

[Holter monitoring of ventricular arrhythmia during the 24 first hours of myocardial infarction treated with intravenous thrombolysis]

The aim of this study was to assess ventricular arrhythmias after intravenous thrombolysis for acute myocardial infarction and to determine their relationship with coronary artery patency. A 24 hour Holter recording was started 3.1 +/- 0.2 hours after the onset of pain in 40 patients (age 54 +/- 1.6 years, 42.5% anterior infarcts) treated by streptokinase (42.5%) or tissue plasminogen activator (57.5%) within 3.3 +/- 0.2 hours of the beginning of symptoms. The arrhythmias were analysed on a Marquette 8000 computer. Coronary angiography was systematic and was performed 26.7 +/- 2.5 hours (within 4 hours in 60% of patients) after the onset of pain to define coronary artery patency (TIMI 2 and 3: 72.5%) or occlusion (TIMI 0 or 1: 27.5%). Ventricular arrhythmias were common and generally well tolerated (one defibrillation for ventricular fibrillation). Accelerated idioventricular rhythms and ventricular tachycardias were equally prevalent in patients with patent arteries (90% and 83%) as with occluded arteries (82% and 73%). The prevalence of sustained ventricular tachycardias (> 15 complexes) and of early accelerated idioventricular rhythms (< or = 6 hours) was significantly higher in patients with patent coronary arteries: 38% versus 0% (p < 0.05) and 76% versus 18% (p < 0.01). These arrhythmias may be considered to be non-invasive markers of early coronary reperfusion, with a sensitivity of 38 and 76% and a specificity of 100 and 82%. Coronary patency was associated with higher numbers of ventricular extrasystoles, ventricular tachycardias and accelerated idioventricular rhythms by a factor of 14, 13 and 32 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Early hospital discharge after uncomplicated myocardial infarction: strategies]

Considerable advances have been seen in recent years in the diagnostic and therapeutic management of myocardial infarction. Furthermore, approximately 50% of patients hospitalised for a myocardial infarction have shown no evidence of any complication by the 3rd day of the disease. With this in mind, the authors show that early discharge from hospital at the end of the first week is possible in perfect safety for the majority of these patients, most often treated by thrombolysis, based upon precise knowledge of the severity of arterial disease and of left ventricular function, and the detection of any residual ischemia or possible rhythm disturbances. Only patients with three vessel disease have a higher risk of residual angina and should theoretically be excluded from such programmes. Ambulatory rehabilitation is an essential adjuvant, contributing to a faster return to work and a decrease in health care costs.

Thymic nurse cells exclusively bind and internalize CD4+CD8+ thymocytes

Thymic nurse cells (TNC) contain 20-200 thymocytes within specialized vacuoles in their cytoplasm. The purpose of the uptake of thymocytes by TNCs is unknown. TNCs also have the capacity to present self-antigens, which implies that they may serve a function in the process of thymic education. We have recently reported the development of thymic nurse cell lines that have the ability to bind and internalize T cells. Here, we use one of these TNC lines to identify the thymocyte subpopulation(s) involved in this internalization process. TNCs exposed to freshly isolated thymocytes bind and internalize CD4 and CD8 expressing thymocytes (CD4+CD8+ or double positives) exclusively. More specifically, a subset of the double-positive thymocyte population displayed binding capacity. These double-positive cells express cell surface alpha beta type T cell antigen receptor (TCR), as well as CD3 epsilon. Binding was not inhibited in the presence of antibodies against CD3, CD4, CD8, Class I antigens, or Class II antigens. These results describe two significant events in T cell development. First, TNCs exclusively bind and internalize a subset of alpha beta TCR expressing double-positive T cells. Also, binding is facilitated through a mechanism other than TCR recognition of major histocompatibility complex antigens. This suggests that thymocyte internalization may be independent of the process used by TNCs to present self-antigen.

[Large thrombus in the left atrium and rheumatic mitral stenosis. Value of cardiac imaging]

Thromboses in the left atrium, which are a commonplace complication of mitral stenoses with major dilatation of the left atrium lead to a major risk of systemic embolism. It is important to discover them, because they constitute a contraindication to mitral valvuloplasty. The authors report the case of a large left intra-atrial thrombus complicating a pure, tight, mitral stenosis. They also highlight the value of new medical imaging techniques in cardiology: chest CT scan, nuclear magnetic resonance and cardiac scintigraphy. Subsequently, transesophageal cardiac ultrasound, not available in France at the time for this patient, has become the reference method for visualizing and detecting left intra-atrial thrombi.

Holter recording of ventricular arrhythmias during intravenous thrombolysis for acute myocardial infarction

Ventricular arrhythmias during thrombolysis for acute myocardial infarction and their relation to coronary artery patency were examined. Twenty-four-hour Holter monitoring was begun 3.1 +/- 0.2 hours after onset of pain in 40 patients (age 54 +/- 1.6 years; anterior infarction 42.5%) treated with streptokinase (42.5%) or recombinant tissue-type plasminogen activator (57.5%) (delay from pain 3.3 +/- 0.2 hours). A Marquette 8000 computer was used for Holter analysis. The infarct-related artery was considered as patent (72.5%) or non-patent (27.5%) according to coronary angiography (delay from pain 26.7 +/- 2.5 hours; 60% less than 24 hours). Ventricular arrhythmias were present in all patients. Tolerance was good (1 cardioversion for ventricular fibrillation). The incidence of accelerated idioventricular rhythm was not different between patients with a patent and nonpatent artery (90 vs 82%), nor for ventricular tachycardia (VT) (83 vs 73%). Coronary artery patency was associated with a 14-, 13- and 32-fold increase of ventricular premature complexes, VT and accelerated idioventricular rhythms, respectively. The increased incidence of sustained VT (patent 38%; nonpatent 0%; p less than 0.05) and early (before the first 6 hours) accelerated idioventricular rhythm (patent 76%; nonpatent 18%; p less than 0.01) associated with artery patency suggests that these arrhythmias may be noninvasive diagnostic criteria for reperfusion (sensitivity 38 vs 76%, and specificity 100 vs 82%). A positive correlation was found between the frequency of ventricular premature complexes and VT, and peak creatine kinase.

The immortalization of thymic nurse cells by SV40 virus

Thymic nurse cells (TNCs) are stromal elements that contain between 20 and 200 T cells within their cytoplasm. Because of this unique feature they are believed to play a role in thymocyte development. Unfortunately, it has been difficult to obtain pure TNCs in quantities sufficient for extensive evaluation of their thymic function. As a result, only a limited amount of information is available that characterizes TNCs or the T cell population(s) found within their cytoplasm. We have now used SV40 to infect and immortalize TNCs from C57BL/6 mice. SV40-transformed TNCs were found to specifically bind and internalize cells from an immature thymocyte line isolated in our laboratory. These results describe a method of obtaining pure populations of TNCs for future studies of their thymic function, and suggest that binding to specific subpopulations of lymphoblasts may be necessary for internalization.

Relationship between mixed venous oxygen saturation and cardiac index in patients with chronic congestive heart failure

The use of mixed venous oxygen saturation (SvO2) in patients with chronic congestive heart failure (CHF) has been advocated to analyze the action of therapy on cardiac index (CI). To evaluate the relationship between CI and SvO2, ten CHF patients (mean age 65 years) were studied before and one, two, three, four (T4), six, eight and 24 hours after oral administration of an angiotensin converting enzyme (ACE) inhibitor (perindopril, 4 mg). At T4, a 12 percent increase in CI (p less than 0.01) was associated with a 16 percent decrease in arteriovenous oxygen difference (p less than 0.01), a 13 percent increase in mixed venous oxygen pressure (PvO2) (p less than 0.01), and a 9 percent increase in SvO2 (p less than 0.05) with no significant change in arterial oxygen pressure. There was no correlation between CI and SvO2 (r = 0.22) and between CI and PvO2 (r = 0.23). Individual analyses were performed and patients were divided into two groups based on CI versus SvO2 r value; group 1, n = 6, r greater than 0.65 (0.65-0.90), group 2, n = 4, r less than 0.65 (0.14-0.20). The lack of correlation in group 2 was due to a drug-dependent increase in oxygen consumption (VO2) +18 percent vs -3 percent in group 1 (p less than 0.05) associated with a lack of increase in PvO2 +3 percent vs +14 percent in group 1 (p less than 0.05) despite a similar increase in oxygen availability +19 percent versus +16 percent. It was concluded that (1) a correlation between CI and SvO2 is not found in every patient with CHF; (2) the lack of correlation in four out of our ten patients was due to an associated and significant increase in CI and VO2 in group 2; (3) group 2 patients probably had an important oxygen debt before treatment; (4) SvO2 cannot be used instead of CI to determine the hemodynamic consequences of the use of cardiovascular drugs.

[Listeria rhombencephalitis caused by Listeria monocytogenes with a cerebrospinal fluid initially normal]

A case of rhombencephalitis due to Listeria monocytogenes in a non immunocompromised patient, with initially normal cerebrospinal fluid, was marked by potentially fatal neurovegetative disorders and severe neurological sequelae partly due to delay in diagnosis and treatment. The possibility of Listeria infection should be considered in patients with fever and cranial nerves deficits, in order to initiate an appropriate antibiotic therapy and to keep the subject under close monitoring in an intensive care unit.

Mitral calcification in aortic stenosis

To appreciate the incidence, the promoting factors and the consequences of mitral calcification in aortic stenosis (AS), the data from 675 patients operated on for AS were reviewed. Mitral calcification was revealed by fluoroscopy, echocardiography and/or surgery. Mitral annular calcification (MAC) was observed in 169 patients (25%). In patients with MAC, females were more frequent (42.3 vs. 17.9%, P less than 0.0001), age was greater (64 vs. 58 years, P less than 10(-7)), AS was more severe (0.6 vs. 0.7 cm2, P less than 0.002), and LV walls were thicker (interventricular septum 13.5 vs. 12 mm, P less than 0.0003 posterior wall 12.8 vs. 11.9 mm, P less than 0.004). First-degree AV block was more frequent in patients with MAC but did not lead to more frequent pacemaker implantation. Mitral anterior leaflet calcification was noted in 215 patients (31.8%). When massive, it created mitral stenosis which, in one case, required later mitral replacement. Five- and ten-year actuarial survival rates were not different in patients with or without mitral calcification. We conclude that mitral calcification is frequent in AS. Promoting factors for MAC are age, severity of AS, and female gender.

[Hepatic and renal toxicity of paracetamol in chronic alcoholic patient]

After taking paracetamol regularly in therapeutic doses, a non-cirrhotic alcoholic subject developed hepatic necrosis and acute renal failure. This case is compared with 13 others found in the literature, and the clinical, biochemical and histological characteristics of such accidents are described. The severity of the acute renal failure is proven by the fact that 50% of the patients had to be put under dialysis. The potentiation of acetaminophen renal and hepatic toxicity by alcohol toxicity is discussed. The principal mechanism of enhancement is the activation of the cytochrome P 450 system associated with depletion of intracellular glutathione.

Comparison of non-protected lower respiratory tract secretions and protected specimen brush samples in the diagnosis of pneumonia

The aim of this prospective study was to compare the results obtained with the non-protected lower respiratory tract secretions samples (LRS) with the protected specimen brushes (PSB) performed through a fiberoptic bronchoscope in mechanically ventilated patients, when pneumonia was suspected. The diagnosis of pneumonia was ultimately made at the end of the hospitalisation, in a double-blind manner by 2 members of the medical staff not aware of the bacteriologic results of LRS and PSB. LRS and PSB were performed in 24 patients. PSB culture was considered as positive at a level of 10(3) colony-forming units per milliliter (cfu/ml) microorganisms. Twenty-five samples from 24 patients were divided as follows: (1) LRS (-) and PSB (-) 5 samples: the clinical diagnosis of pneumonia was never established. (2) LRS (+) and PSB (+) 10 samples: the clinical diagnosis of pneumonia was always established, 2 microorganisms were involved 4 times and 1 microorganism 6 times. (3) LRS (+) and PSB (-) 10 samples: the clinical diagnosis pneumonia was retained in 3 with the possibility of false negative PSB. We conclude that (1) a negative LRS eliminated the diagnosis of pneumonia without PSB; (2) a positive LRS was not sufficient to diagnose pneumonia since PSB was negative in 50% of all LRS (+) cases; (3) the possibility of a false negative PSB must be kept in mind particularly in patients previously treated with antibiotics; (4) 2 microorganisms may be responsible for the pneumonia if the previously determined, as significant, bacteriological count (greater than or equal to 10(3) cfu/ml) appears to be accurate.

Pharmacokinetics of pefloxacin and amikacin administered simultaneously to intensive care patients

Ten adult patients with severe infections in an intensive care unit were treated simultaneously with 6 mg/kg pefloxacin and 7.5 mg/kg amikacin, infused i.v. over 1 h every 12 h for 5 days. Twelve h after the last infusion, pefloxacin alone was administered orally (400 mg tablet) every 12 h for 10 days. The pharmacokinetics of pefloxacin and its main metabolites, norfloxacin and pefloxacin N-oxide, were determined after the first (Day 1) and last (Day 5) infusions and after the last oral dose (Day 15). The kinetics of amikacin was determined after the first and the last infusion. The maximal and minimal steady-state plasma concentrations of amikacin were 27.3 and 3.3 mg/l. The total plasma clearance was 83.1 and 67.0 ml/min after the first and the last infusions, respectively, and the half-life was 3.9 and 5.0 h. The maximal and minimal steady-state plasma concentrations of pefloxacin were 13.1 and 7.9 mg/l after i.v. infusion and 13.4 and 9.0 mg/l after oral administration. Pefloxacin elimination (t1/2) increased from 11.3 h after the first infusion to 19.4 h after the last infusion and 21.1 h after the last oral dose. Total body clearance decreased from 90.8 (Day 1) to 51.9 (Day 5) and 56.4 ml/min (Day 15). The volume of distribution did not change significantly over the course of pefloxacin. Mean steady-state plasma concentrations of norfloxacin and pefloxacin N-oxide were respectively 0.5-0.6 mg/l and 0.9-1.3 mg/l after intravenous and oral administration of pefloxacin. There were no pharmacokinetic interaction between the drugs. The dosage regimen led to plasma concentrations of pefloxacin and amikacin within their therapeutic range.