Alterations in endocardial vascular resistance after reperfusion in a low flow, high demand model of ischemia: effects of dipyridamole and WEB-2086, a platelet-activating factor antagonist.

To determine if alterations in regional coronary vascular resistance could occur in the type of myocardial ischemia present in severe angina pectoris, regional perfusion and function were studied in 35 conscious sedated dogs. A stenosis producing severe hypokinesia of the perfused segment was created for 2 h on the left anterior descending coronary artery and 10 episodes of 1 min of high demand ischemia (atrial pacing at a rate sufficient to induce dyskinesia in the hypoperfused segment) were superimposed before reperfusion. The dogs were randomized into three treatment groups: control (n = 13), dipyridamole (n = 10) or WEB-2086 (n = 12), an antagonist of the effects of the endogenous platelet-activating factor. During stenosis, residual endocardial blood flow in the ischemic but nonnecrotic area averaged 0.72 +/- 0.14, 0.38 +/- 0.13 and 0.68 +/- 0.17 ml/min per g in the control, WEB-2086 and dipyridamole groups, respectively. Twenty-four hours after reperfusion, endocardial blood flow in the ischemic area was significantly lower in control dogs (1.04 +/- 0.15 ml/min per g) than in dogs treated with WEB-2086 (1.44 +/- 0.28 ml/min per g; p less than 0.03) or dipyridamole (3.00 +/- 0.83 ml/min per g; p less than 0.01). Accordingly, in control dogs, endocardial coronary vascular resistance in the ischemic area was increased after reperfusion from 85 +/- 11 to 124 +/- 27 mm Hg/(ml/min per g) (p less than 0.05) after 24 h. In contrast, coronary vascular resistance in the ischemic area remained unchanged in dogs receiving WEB-2086 (77 +/- 8 to 79 +/- 9 mm Hg/(ml/min per g); p = NS) and it decreased significantly in dogs receiving dipyridamole (72 +/- 8 to 44 +/- 8 mm Hg/(ml/min per g); p less than 0.01). Regional function after 24 h remained depressed in all three groups. These data indicate that low flow, high demand ischemia induces alterations in the subendocardial microvasculature. Such alterations in regional coronary vascular resistance might play a role in several forms of ischemic heart disease such as in severe angina, but they appear susceptible to improvement by therapeutic interventions that influence granulocyte and platelet activation.

Significance of pulmonary input impedance in right ventricular performance.

Right ventricular adaptation to changes in pulmonary input impedance was studied in open-chest dogs. When identical increases in pulmonary vascular resistance are imposed by two different manoeuvres (lung inflation and clamping of the left pulmonary artery), external power and pressure-time integral of the right ventricle at similar filling pressure are always greater during clamping than during inflation. Further studies demonstrate that, at equal increases in pulmonary input impedance modulus at 0 Hz, the clamping produces a greater change in the sum of the first three harmonics of impedance than the inflation (respectively +77% and -10% vs control modulus; -82% and +8% vs control phase). These impedance changes could explain the different behaviour of the right ventricle either by better matching of the ventricular internal impedance or by functional modification of the outflow tract.

Diastolic properties in canine hypertensive left ventricular hypertrophy: effects of angiotensin converting enzyme inhibition and angiotensin II type-1 receptor blockade.

OBJECTIVE: Angiotensin II has been suggested to be involved in the pathogenesis of diastolic dysfunction in left ventricular hypertrophy (LVH). The purpose of this study was to asses the effects of enalaprilat and L-158,809, an angiotensin II type-1 receptor antagonist, on LV diastolic function in 16 normal control dogs and 20 LVH dogs with perinephritic hypertension. METHODS: LV hemodynamics was studied before and after intravenous injection of enalaprilat (0.25 mg/kg) or L-158,809 (0.3 mg/kg). The hemodynamic data were analyzed in relation to the changes in myocardial blood flow (measured by radioactive microspheres) and in the circulating angiotensin II and norepinephrine levels. RESULTS AND CONCLUSIONS: At baseline, significant increases were observed for LV/body weight ratio as well as LV systolic and end-diastolic pressure in the LVH dogs (all P < 0.01 vs. the control group). In addition, LV relaxation time constant was prolonged and the chamber and myocardial stiffness constants were increased (P < 0.01) in the LVH dogs, suggesting an impairment of LV diastolic function. Administration of enalaprilat or L-158,809 improved LV stiffness constants in the LVH dogs (P < 0.05). The diastolic LV pressure-diameter relation shifted downwards in the LVH dogs whereas diastolic distensibility was not altered in the control dogs. Although the circulating angiotensin II levels were significantly decreased by enalaprilat in the LVH dogs, they did not correlate with the changes in the stiffness constants. Furthermore, the alterations of LV diastolic properties in the LVH group could not be attributed to myocardial perfusion, which was rather decreased by administration of enalaprilat and L-158,809. These results suggest that angiotensin II, particularly at the local level, is involved in the pathogenesis of diastolic dysfunction in pressure-overload LVH. The data also support the concept that ACE inhibitors and angiotensin II receptor blockers are potentially beneficial in the treatment of the hypertrophied heart.

Induced response to hypercapnia in the two-compartment total cerebral blood volume: influence on brain vascular reserve and flow efficiency.

This study was undertaken to investigate the mechanisms of CBF increase as induced by hypercapnia. It was achieved in anesthetized rats by determining total cerebral blood volume (TCBV), parenchymal blood (CBV), plasma (CPV), erythrocyte (CEV) volumes and cerebral hematocrit (CHct) as well as CBF at about 40, 60, and 80 mm Hg PaCO2. TCBV was measured by a noninvasive blood dilution method using [99mTc]pertechnetate. CBV, CPV, and CEV were measured on isolated brain by 125I-serum albumin and 51Cr-erythrocytes. CBF was measured by both [131I/14C]iodoantipyrine and 57Co-microsphere extractions. The extraparenchymal blood volume (ECBV) was evaluated by subtracting CBV from TCBV. Under normocapnia, ECBV was 2.8 times larger than CBV. Under moderate hypercapnia, ECBV increased by 44%, CBV was not modified, and CBF increased by 52%. These results demonstrate that the main site of vasodilation is located in the extraparenchymal vasculature, which thus acts as a vascular reserve. By contrast, under severe hypercapnia, ECBV remained unchanged, whereas CBV then increased by 17%; CBF simultaneously showed an additional augmentation of either 52 or 309% when diffusible tracer or microspheres were used. This important increase in CBF cannot be explained either by capillary recruitment of closed capillaries or by active diameter lengthening of already open capillaries. The concomitant and great increase in capillary blood velocity was also shown to reduce cerebral flow efficiency, a situation consistent with a "luxury perfusion."

Angiotensin II and endothelin-1 receptor antagonists have cumulative hypotensive effects in canine Page hypertension.

OBJECTIVE: To evaluate whether the cumulative hypotensive effect of the endothelin-1 receptor antagonist bosentan, previously demonstrated in the presence of an angiotensin converting enzyme inhibitor, persists under angiotensin II receptor blockade with losartan. DESIGN: The model of hypertension was canine renovascular hypertension (Page hypertension). METHODS: Ten conscious dogs, studied on two occasions, were administered losartan (a 0.1 mg/kg bolus plus 90 min infusion at 0.1 mg/kg per min) and then bosentan vehicle (experiment I) or losartan and then two cumulative doses of bosentan (a 0.3 mg/kg bolus plus 30 min infusion at 0.7 mg/kg per min; and a 3 mg/kg bolus plus 30 min infusion at 7 mg/kg per min; experiment II). RESULTS: At the end of the study, mean aortic pressure in dogs had decreased by 14% in experiment I (from 139 +/- 4.7 to 119 +/- 4.7 mmHg, P<0.05), whereas a 28% reduction occurred in experiment II (from 145 +/- 8.9 to 104 +/- 5.0 mmHg, P<0.005), corresponding to an additional 14% decrease after administration of bosentan (P<0.005 between groups). This cumulative effect of bosentan was related to a decrease in systemic vascular resistance (from 1220 +/- 119 to 847 +/- 189 mmHg/ml per min per kg x 10(3), P<0.05). Plasma angiotensin II level increased similarly in both experiments (in experiment I from 133 +/- 43 to 622 +/- 145 pg/ml, P=0.01; in experiment II from 198 +/- 63 to 771 +/- 134 pg/ml, P<0.005) whereas plasma endothelin-1 level increased only in experiment II (from 3.8 +/- 0.4 to 32.7 +/- 3.2 pg/ml, P<0.001). CONCLUSION: The cumulative hypotensive effect of bosentan suggests that, besides angiotensin II, endothelin-1 is independently involved in the pathophysiology of hypertension, which presents new therapeutic perspectives.

Technetium-99m-pertechnetate as a whole blood marker for brain perfusion studies.

UNLABELLED: In the brain, diffusible 99mTc-pertechnetate behaves as an intravascular indicator because it is confined within the circulation by the blood-brain barrier, allowing its use for noninvasive dynamic evaluation of cerebral circulation. For this application 99mTc has often been claimed to be a plasma marker. This study examines the validity of such a claim which has not yet been proven in vivo. METHODS: The relative amount of 99mTc in the red cells circulating in large vessels was compared to the corresponding hematocrit (LV Hct) during the rapid (t/2 = 1.98 min) and slow (t/2 = 84 min) phases of 99mTc disappearance from the circulation after bolus intravenous injection. These comparisons were performed on rats at 2 (n = 3), 5 (n = 6), 10 (n = 6) and 20 (n = 9) sec after intravenous injection for the rapid phase and 5 (n = 5), 30 (n = 4), 60 (n = 6) and 120 (n = 6) min after intravenous injection for the slow phase. RESULTS: The results show that the relative amount of intravascular 99mTc fixed to red cells did not differ statistically from LV Hct until at least 1 hr after intravenous administration. This homogeneous distribution of 99mTc in blood was indisputable during the first 20 sec but became progressively less evident and disappeared after 2 hr. Such behavior was attributed to a progressive increase of free 99mTc, which, in whole blood, amounted to 4% at 20 sec and 25% at 2 hr after injection. CONCLUSION: Because it is a 96% whole blood marker early after intravenous administration, 99mTc is a reliable agent for first-pass studies of whole blood circulation in the brain.

Force-velocity-length relations in hypertrophic cardiomyopathy: evidence of normal or depressed myocardial contractility.

To assess myocardial contractility in patients with hypertrophic cardiomyopathy (HC), force-velocity-length relations were analyzed during left ventricular (LV) ejection. LV pressure, volume and wall stress data in 15 patients with HC were analyzed and compared with values from 32 normal subjects. Patients with HC had a greater LV mass than did normal subjects (272 versus 96 g/m2, p less than 0.001), elevated LV end-diastolic pressure (17.5 versus 9.8 mm Hg, p less than 0.01) and impaired LV relaxation compared with those of normal subjects. Patients with HC also had a greater ejection fraction (84 +/- 7 versus 74 +/- 8%, p less than 0.01) and mean velocity of shortening than did normal subjects. However, in patients with HC, end-systolic stress (60 +/- 29 versus 187 +/- 61 kdyne/cm2, p less than 0.001) was significantly lower. End-systolic volume and stress data were linearly related in normal subjects (r = 0.88), and values from patients with HC fell either within the lowest part of the 95% confidence interval of this normal relation or outside it in the zone of depressed contractility (11 patients with HC). In addition, the slopes of the relations between end-systolic wall stress and ejection fraction or mean velocity of shortening were abnormal in patients with HC; the slope of the stress-volume trajectory during late ejection was also depressed in 12 patients with HC (average slope 2.6 versus 5.5 kdyne/cm5/m2, p less than 0.001). Thus, there is no evidence of a hypercontractile state in patients with HC; their high values of ejection phase indexes may be explained by a reduction in myocardial afterload.

Effects of nicardipine and nisoldipine on myocardial metabolism, coronary blood flow and oxygen supply in angina pectoris.

The effects of the calcium antagonists nicardipine and nisoldipine on left ventricular (LV) metabolism were analyzed in 32 patients with angina pectoris. Measurements were made at a fixed heart rate under the basal state and during a cold pressor test (CPT). After administration of the drugs, coronary blood flow increased significantly and the mean aortic pressure decreased by 10% (p less than 0.01) in the basal state and by 11% (p less than 0.01) during CPT. Despite the reduction in pressure-rate product, myocardial oxygen consumption was unchanged in the basal state (18 +/- 4 vs 19 +/- 4 ml/min, difference not significant) and during CPT (21 +/- 5 vs 21 +/- 5 ml/min, difference not significant); this discrepancy between a reduced pressure-rate product and an unchanged oxygen consumption was also noted when nicardipine was given after propranolol (0.1 mg/kg; 12 patients). Both agents also increased LV lactate uptake, particularly during CPT (+13 mumol/min, p less than 0.05 vs control CPT) and reduced LV glutamine production. In 10 patients in whom 14C-lactate was infused, the chemical LV lactate extraction ratio increased more than the 14C-lactate extraction ratio after administration of the drugs, indicating a reduction in LV lactate production. The data are consistent with the hypothesis that nicardipine and nisoldipine improve perfusion and aerobic metabolism in chronically ischemic areas, resulting in an augmented oxygen consumption and in a reduced lactate production.

Cardiac function early after repair of tetralogy of Fallot.

Hemodynamics of 12 patients with tetralogy of Fallot were monitored during the first 72 hours after surgical repair. Total immediate repair in 5 patients was followed after 24 hours by a greater decrease in cardiac index than that observed in the group of 4 patients with previous palliative shunt (minus 25 plus or minus 6 vs. minus 1 plus or minus 7 per cent, p smaller than 0.025). This difference disappeared after 48 hours, and the short-term follow-up periods of these two groups were equally smooth. Six patients with pulmonary stenosis requiring the placement of an outflow patch had higher right ventricular filling pressures (after 24 hours 13.8 vs. 10.8 mm. Hg, p smaller than 0.025; 2 to 4 weeks later 9.6 vs. 5.5 mm. Hg, p smaller than 0.05), suggestive of a persistent right ventricular depression. This ventricular depression must be attributed to the induced pulmonary insufficiency and to the presence of akinetic areas. Both these factors should therefore be carefully minimized during the surgical procedure.

Late effects of X irradiation on regulation of cerebral blood flow after whole-brain exposure in rats.

Hemodynamic parameters such as total cerebral blood volume (total CBV), cerebral parenchymal blood volume (CBV), cerebral blood flow (CBF) and cerebral blood velocity index were measured in rats 6, 12 and 18 months after single exposures of brain to 5, 10, 15 and 20 Gy X rays for total CBV, CBF and blood velocity index, and only 20 Gy for CBV. Total CBV and blood velocity index were determined by a noninvasive blood dilution method using [99mTc]pertechnetate and CBF by [131I]iodoantipyrine brain extraction. The CBV was obtained from both parenchymal plasma and erythrocyte volumes measured in isolated brain by 125I-labeled serum albumin and 51Cr-labeled erythrocytes, respectively. Neither the dose nor the time after irradiation influenced total CBV. Nevertheless, CBV decreased slightly while CBF decreased strongly at 12 and 18 months after 20 Gy. In contrast, the blood velocity index increased progressively at 12 and 18 months after 15 Gy and at all times after 20 Gy. According to the coexistence in irradiated brains of a remodeling with microvascular occlusions and dilated abnormal vessels, this lowered CBF can be explained by the smaller number of open capillaries and a "steal phenomenon" through low-resistance channels developed in the parenchymal and extraparenchymal vasculatures. Such a "steal phenomenon" is also supported by the response of the blood velocity index, which appears to be the earliest sensitive index for the detection of hemodynamic changes with respect to time (6 months) and dose of radiation (15 Gy).

Diagnosis of asymptomatic common bile duct stones: preoperative endoscopic ultrasonography versus intraoperative cholangiography--a multicenter, prospective controlled study. French Associations for Surgical Research.

BACKGROUND: In patients with symptomatic cholelithiasis, preoperative diagnosis of common bile duct (CBD) stones can modify the therapeutic strategy. The aims of this prospective, controlled multicenter study were to assess the feasibility, concordance, discordance, and indexes such as sensitivity, specificity, positive and negative predictive values, and accuracy of preoperative endoscopic ultrasonography compared with those of intraoperative cholangiography (IOC) in the diagnosis of asymptomatic CBD stones (i.e., patients undergoing cholecystectomy with no clinical or biologic evidence of CBD stones). METHODS: From October 1993 to October 1995, 240 consecutive patients with symptomatic cholelithiasis, scheduled for cholecystectomy in 14 surgical centers, were enrolled in this study. All patients were selected for this study according to a preoperative high-risk CBD stone predictive score. Each patient underwent both endoscopic ultrasonography and IOC, as well as surgical exploration of the CBD when stones were detected during one or both preoperative investigations. All patients were seen 1 months and 1 year after operation to check for residual stones. RESULTS: The feasibility of endoscopic ultrasonography was significantly higher overall than that of IOC (99% vs 90%; p < 0.001), except when IOC was through a laparotomy (97% vs 93%; p = 0.16). The number of patients available for study was 215. In 198 cases (92%), results of both investigations were in concordance (161 negative and 37 positive values). Seventeen cases (8%) were discordant. There was overall concordance between the two investigations (kappa coefficient 0.764; 95% confidence interval 0.66 to 0.87), but the percentage of discordance was in favor of IOC. Sensitivity and specificity of IOC were significantly higher than those of endoscopic ultrasonography (1.00 and 0.98 vs 0.85 and 0.93, respectively). With a prevalence of CBD stones of 19%, positive and negative predictive values of IOC were significantly higher than those of endoscopic ultrasonography (0.93 and 1.00 vs 0.75 and 0.96, respectively). CONCLUSIONS: Although endoscopic ultrasonography is feasible more often than IOC, IOC is associated with a slightly lower degree of discordance and better information indexes and remains an efficient method of investigation for CBD stones. Endoscopic ultrasonography can be suggested in preference to endoscopic retrograde cholangiography when postoperative residual stones are suspected but need not be performed routinely before cholecystectomy.

Total cerebral blood volume calculated from a model of [99mTc]pertechnetate distribution in the head.

A method for calculation of the blood volume from the internal carotid and vertebral arteries to the internal jugular veins [total cerebral blood volume (TCBV)] was validated. This was achieved noninvasively in anesthetized rats from the time-activity curve recorded over the head after [99mTc]pertechnetate (Tc) intravenous bolus injection. Tc had the advantage over many other tracers in that it rapidly and evenly distributed in blood cells and plasma. Tc was found to behave in the head according to a two-parallel-compartment model containing a fast cerebral compartment and a slow extracerebral compartment. This model was mathematically described by a sum of two lagged normal density curves (LNDC) that fitted the head curve adequately. Responses of the LNDC parameters to flow and volume variations were first tested on a hydraulic setup. TCBV was calculated from the LNDC parameters of the cerebral fast compartment and the simultaneously determined cardiac output. In normocapnic rats, TCBV amounted to 49 +/- 7 (SD) microliters/g, distributed approximately two-thirds in the extra-parenchymal and one-third in the intraparenchymal cerebral vasculatures.

Preoperative evaluation of the probability of common bile duct stones. French Association for Surgical Research.

BACKGROUND: This study was done to determine if certain criteria could predict the presence of common bile duct stones in patients with symptomatic gallstones. It was hoped that patients could be identified in whom intraoperative cholangiography was unnecessary. STUDY DESIGN: One hundred seventy-five patients, from 15 surgical centers, were prospectively enrolled. For each patient, the preoperative score (Huguier score) previously published was calculated according to clinical and ultrasound data: age, diameter of the common bile duct, diameter of the smallest gallstone, history of biliary colic, and acute cholecystitis. All patients underwent an open cholecystectomy and an intraoperative cholangiography. The absence or presence of a common bile duct stone was evaluated during the operation, if necessary, after an instrumental investigation of the common bile duct. RESULTS: Ultrasound was not interpretable in eight (5 percent) of 175 patients. Final analysis was made from the charts of the 167 remaining patients. Thirty (18 percent) had common bile duct stones. When the score was equal to or greater than 3.5, the risk of having a common bile duct stone was 24 percent (27 of 111). When the score was less than 3.5, this risk was 5 percent (three of 56). CONCLUSIONS: Huguier's score is well assessed and can be safely used. Intraoperative cholangiography could be avoided in 33 percent of patients when the score is less than 3.5 (56 of 167).

Comparison of two methods for the measurement of rat liver methylmalonyl-coenzyme A mutase activity: HPLC and radioisotopic assays.

Methylmalonyl-coenzyme A mutase (MCM) is a 5'-deoxyadenosylcobalamin-linked mitochondrial enzyme that catalyzes the isomerization of L-methylmalonyl-coenzyme A to succinyl-coenzyme A. In vitro assays of total and holo-MCM activities are important tools for investigating the cobalamin pathway. Several methods have been described for measuring MCM activity. The most commonly-used method is a radioassay based on the permanganate oxidation of DL[CH(3)-(14)C]methylmalonyl-coenzyme A, but radiometric methods are insensitive, laborious, and time-consuming. Therefore, we have compared this method with a nonradiometric assay, potentially most sensitive, based on the separation of methylmalonyl-coenzyme A and succinyl-coenzyme A by high performance liquid chromatography (HPLC). We determined the optimal assay conditions and the reproducibility and sensitivity of each technique. The results obtained by the two techniques were very different: the specific activities obtained by the permanganate oxidation method (0.039 +/- 0.013 nmol/min/mg protein for the holo-MCM activity and 1.90 +/- 0.69 nmol/min/mg protein for the total-MCM activity) were threefold lower than those obtained with the HPLC method (0.124 +/- 0.011 nmol/min/mg protein for the holo-MCM activity and 6.15 +/- 0.76 nmol/min/mg protein for the total-MCM activity). The coefficients of variation for the radiometric method (18.4-40.6%) were three to five times greater than those for the HPLC assay (3.5-12.2%). This demonstrates the lack of sensibility and reproducibility of the permanganate radioassay. Thus, the radiometric method is not suitable for measuring low mutase activities such as the holo activities in tissues. The intrinsic inconvenience of the radiometric assay indicates that the HPLC method is a method of choice for measuring MCM activity.

Release of mifepristone from biodegradable matrices: experimental and theoretical evaluations.

Diffusion of mifepristone in poly [(D,L) lactide-co-glycolide)] films was studied by release experiments. Five 50/50 copolymers of increasing molecular weights were used. The degradation effects were shown by gel permeation chromatography (GPC). Release kinetics show the effect of copolymer molecular weights on diffusion and degradation properties of loaded films. A new theoretical model for drug release from a biodegradable matrix was proposed with two assumptions: correlation of the diffusion coefficient with the polymer molecular weight and existence of a first order degradation kinetic. Higuchi's equation is verified at early time and the diffusion coefficient in the non-degraded polymer can be measured. The degradation constant is determined at long time and is compared with the results of GPC.

[Kussmaul's paradoxical pulse. Etiopathogenic aspects]. / Le pouls paradoxal de Kussmaul. Aspects étiopathogéniques.

Paradoxical pulse (reduction in systolic blood pressure during inspiration) is a sign common to many pathological conditions affecting the heart and lungs. The aim of this paper was to determine its mechanism on the basis of recent publications in the literature, supported by personal clinical cases. Three cases of pulmonary embolism with paradoxical pulses of over 30 mm Hg are reported. In all three cases, cardiac and pulmonary function were normal before the embolism. The significant findings were a marked elevation in inspiratory transmural RA pressure (average 10 mm Hg), contrasting in one case with normal LV inspiratory transmural pressures. Two factors seem to play a role in the genesis of a paradoxical pulse: firstly, increased left ventricular afterload due to negative intrathoracic pressure during inspiration, and, secondly, a reduction of left ventricular compliance during inspiration related to mechanical interference between the two ventricles. In the absence of increased central venous pressure, increased left ventricular afterload probably plays the major role in the inspiratory reduction of peak systolic pressure (e.g. "physiological" paradoxical pulse, hypovolaemia, asthma). On the other hand, when central venous pressure is increased, the phenomenon of mechanical interference related to improved right ventricular filling during inspiration, added to increased left ventricular afterload, may result in very considerable paradoxical pulses (e.g. pulmonary embolism, cf. the cases reported: paradoxical pulses of over 30 mm Hg). Finally, certain pathological entities are associated with the greater role of mechanical interference (e.g. tamponade, constrictive pericarditis) for the principal causes, especially pulmonary embolism and pericardial effusion.

[A large aneurysm of the inferior mesenteric artery. Apropos of a case. Review of the literature]. / Gros anévrysme de l'artère mésentérique inférieure. A propos d'une observation. Revue de la littérature.

The prevalence of inferior mesenteric aneurysms is difficult to evaluate in the literature, only four cases having been published up to the present. The case described here was a large aneurysm of the inferior mesenteric artery measuring 10 cm by 8 cm of atheromatous origin, discovered echotomographic investigation of an abdominal mass and confirmed by aortography. Operation consisted in endoaneurysmorrhaphy with reimplantation of the main branch supplying the sigmoid arteries into the aorta combined with reimplantation of the right common iliac eroded by the aneurysm into the right side of the aorta. This type of lesion raises two problems: diagnostic: echotomography and digitalised angiography will certainly facilitate the detection of such lesions, the risk of rupture of which is considerable; therapeutic: distal reimplantation of the inferior mesenteric artery which is decided on the basis of its anatomical state and above all the superior mesenteric and coeliac collateral circulation in order to avoid any risk of ischaemia of the descending colon.

Resolution of appendiceal colic following migration of an appendicolith.

The presence of an appendiceal fecalith should not be considered as a categorical sign of acute appendicitis. The fecalith may, however, be responsible for abdominal pain--right lower quadrant tenderness without associated appendicitis, i.e. appendiceal colic. When a patient presents with right lower quadrant abdominal tenderness, abdomino-pelvic computerized tomography (CT) may establish this diagnosis by demonstrating the presence of the appendicolith but without evidence of appendiceal inflammation or infection. Spontaneous migration of the appendicolith may result in cure. In this previously unpublished clinical case, the CT demonstrates the spontaneous passage of the appendicolith, which coincided in time with the resolution of the abdominal pain syndrome. When a patient presents with typical symptoms of appendiceal colic and CT findings of an appendicolith without appendicitis, appendectomy will certainly relieve the pain. But if the stone passes spontaneously, the need for appendectomy is debatable, particularly in a high-risk patient.

Appendiceal actinomycosis complicated by multiple hepatic abscesses.

We report the case of a patient with appendicitis due to actinomycosis, complicated by multiple liver abscesses. Definitive diagnosis was based on histopathologic examination of the resected appendix. Accurate identification of the pathogen led to curative antibiotic therapy of the liver abscesses.