Diastolic heart failure in anaesthesia and critical care

Diastolic heart failure is an underestimated pathology with a high risk of acute decompensation during the perioperative period. This article reviews the epidemiology, risk factors, pathophysiology, and treatment of diastolic heart failure. Although frequently underestimated, diastolic heart failure is a common pathology. Diastolic heart failure involves heart failure with preserved left ventricular (LV) function, and LV diastolic dysfunction may account for acute heart failure occurring in critical care situations. Hypertensive crisis, sepsis, and myocardial ischaemia are frequently associated with acute diastolic heart failure. Symptomatic treatment focuses on the reduction in pulmonary congestion and the improvement in LV filling. Specific treatment is actually lacking, but encouraging data are emerging concerning the use of renin-angiotensin-aldosterone axis blockers, nitric oxide donors, or, very recently, new agents specifically targeting actin-myosin cross-bridges.

[Feasibility and technical problems of sentinel node analysis in melanoma]

BACKGROUND

Development of the sentinel lymph node (SLN) biopsy the last 10 years has changed surgical approach of solid tumor treatment and particularly of melanoma. The aim of our study was to analyze in our hospital, the feasibility of the SLN biopsy technique in order to define a better prognostic classification of melanomas.

PATIENTS AND METHODS

Between July 1999 and October 2003, 97 patients were included in this study in our center. Criteria for inclusion were cutaneo-mucosal melanoma of Breslow >or=1,5 mm, and/or Clarck >or=IV, and/or ulceration, and/or signs of regression, before any surgical margins.

RESULTS

Lymphoscintigraphy (LS) identified at least 1 SLN in 94 cases/97 (97%), thus permitting intraoperative SLN mapping and sentinel node biopsy of at least 1 lymph node in 88 cases/94 (94%). Failure of the SLN procedure was noted in 9 cases: in 3 cases, no lymph node was individualized by LS, in 1 patient, intraoperative SLN mapping failed to find the previously identified SLN and in 5 cases, a SLN was identified by LS and intraoperative mapping but could not be removed because of its deep location and difficulty of dissection. In 17 patients, removal of one or two "non sentinel lymph node(s)" was (were) made by the surgeon because of its (their) suspected aspect (black or large). Among the 88 patients who had dissection of at least 1 SLN, a micrometastasis was detected by standard histological evaluation and/or immunohistochemical stains in 14 cases (16%) and into a "non SLN" in 2 cases (2,3%). The median follow up of patients was 16 months (1- 48 months). Among the 14 patients with positive SLN, 6 (43%) relapsed. The other eight were in complete remission of their melanoma with a mean follow up of 11,44 months . Among the 74 patients with negative SLN, 7 (9,5%) developed a recurrence. Among the 9 patients in whom any sentinel lymph node have been removed, 3 had a relapse (one in transit than on lymph nodes, and two on lymph nodes).

CONCLUSION

Our results are in accordance with the literature, and confirm the feasibility of SLN mapping and of SLN histological analysis in our center. We described in this study technical problems we encountered. Our study also show the prognostic value of this technique. However, advantage in global survey of sentinel node dissection and regional lymph node dissection in cases of micrometastases has still to be demonstrated.

[Homocysteinemia and coronary artery disease: a case-control study in a Tunisian population]

We have determined the prevalence of hyperhomocysteinemia and tested its relationship with coronary heart disease in Tunisian patients. The study included 70 angiogrphically proven coronary patients and 140 age- and sex-matched healthy subjects. Plasma homocysteine folate and vitamin B12 were analyzed by immunoenzymatic methods. Hyperhomocysteinemia was considered for plasma homocysteine concentration >17 micromol/L. Mean plasma homocysteine concentration and hyperhomocysteinemia prevalence were significantly (p<0.001) higher in patients (16.3 +/- 7.9 micromol/L and 29%) than controls (12.6 +/- 4.0 micromol/L and 10%). The association between hyperhomocysteinemia and coronary heart disease persisted after adjusting on main cardiovascular risk factors (multi adjusted odds ratio, 2.99; 95% CI, 1.18-7.59; p=0.02). No association was observed between hyperhomocysteinemia and coronary disease severity and extent. This study showed an independent association between hyperhomocysteinemia and coronary heart disease, suggesting a role of hyperhomocysteinemia in atherothrombogenesis. However, causal relationship is not yet established. Until results of homocysteine-lowering therapy trials become available, hyperhomocysteinemia should be researched and treated in coronary heart disease patients.

Chondroid syringoma of the arm: an unusual localization

Chondroid syringoma (CS) is an uncommon, benign, sweat-gland tumor. The usual presentation is of an asymptomatic, slowly growing mass, typically located on the head and neck region. We present a case of a CS located in the right arm of a 43-year-old woman. This tumor developed slowly over 8 years. The diagnosis of CS was made by histopathological examination; it showed an abundant chondroid stroma intermingled with a fibro-adipoid tissue. There was no recurrence after total excision of the tumor with a 2-year followup. The unusual localization of chondroid syringoma made an accurate preoperative diagnosis difficult and diagnosis was achieved only by microscopy. Surgical tumor excision remains the best therapeutic option to avoid relapses of this tumor. Close followup is recommended because malignant transformation, although rare, is possible.

[Polymorphism insertion/deletion of apolipoprotein B gene: effect on lipid levels in obese patients]

Apolipoprotein B (apoB) is the major proteic component of LDL, VLDL and chylomicrons. Numerous polymorphisms of the apolipoprotein B gene have been described. Particularly, a polymorphism of insertion/deletion located in the coding part of the signal peptide of apoB, associated with modifications of lipid concentrations and the risk of cardiovascular disease, has been reported in the general population. Since obesity is frequently associated with dyslipidemias, the aim of our study was to assess the effect of the insertion/deletion polymorphism of the apolipoprotein B gene on lipid levels in obese subjects. 234 unrelated caucasian obese subjects (74 men and 160 women, aged 39.3 +/- 10.5, BMI : 32.8 +/- 4.7) were recruited. The insertion/deletion polymorphism was determined by electrophoresis in polyacrylamide gels after PCR amplification. The relative frequencies of the Ins and Del alleles were 0.71 and 0.29 respectively. These frequencies were similar to those found in other Caucasian populations. In the whole population, individuals with the Del/Del genotype had significantly higher total-cholesterol to HDL-cholesterol ratios (p = 0.004), LDL-cholesterol to HDL-cholesterol ratios (p = 0.01) and TG-VLDL levels (p < 0.05). They also showed a tendency for higher triglyceride levels (p = 0.09) and lower HDL-cholesterol, apolipoprotein AI and LpAI levels. The allele deletion results in the absence of three amino acids (Leu-Ala-Leu) in the signal peptide of apo B. In the obese people, these structural changes may have some effect on lipid metabolism and cause variation in serum lipid concentrations.

[Distribution of cardiovascular risk factors in a Tunisian cohort of 6901 coronary patients]

The Tunisian epidemiological data on cardiovascular disease in the hospital environment are scarce. The aim of this study was to evaluate the frequency of cardiovascular risk factors and their association in patients hospitalised for coronary disease in coronary care units at Rabta, Charles Nicolle, Habib Thameur and Military hospitals, Tunis, over the period 1994-1998. The clinical features of 6901 patients (75.7% men, 3760 myocardial infarction, 3141 unstable angina) on hospital admission were analysed. The prevalence of smoking, dyslipidemia, hypertension, diabetes and obesity was 86; 49.8; 33.9; 40.7 and 15.2% respectively in the men and 12.9; 52.4; 64.6; 53.4 and 29.8% respectively in women. With this risk factor profile Tunisia has to implement a national strategy of primary prevention and heart health promotion in addition to the efforts recently made in secondary prevention of some chronic disease such as hypertension, diabetes and smoking.

Levosimendan: a new dual-action drug in the treatment of acute heart failure

Levosimendan is a new agent for the treatment of acute heart failure. Levosimendan acts via complementary mechanisms; it enhances contractility by sensitising cardiac myofilaments to calcium and dilates blood vessels by opening ATP-dependent potassium channels. In contrast to traditional inotropes (beta-agonists or phosphodiesterase inhibitors), levosimendan does not raise myocyte calcium levels and is therefore less likely to elicit arrhythmias or to impair diastolic relaxation. The clinical efficacy of levosimendan is supported by four key clinical studies, including more than 900 patients hospitalised for cardiac decompensation due to acutely worsened chronic heart failure or to heart failure following myocardial infarction. When given as short-term therapy, levosimendan enhances cardiac output, reduces systemic vascular resistance and lowers pulmonary capillary wedge pressure. At 31 days post-treatment, mortality rates were halved in decompensated chronic heart failure patients who received levosimendan, compared with those on dobutamine--an advantage sustained at 180 days. Similar survival gains were observed among acute failure patients treated with levosimendan following myocardial infarction. With its substantial haemodynamic and survival benefits, levosimendan is well suited to be part of routine management for patients with acutely decompensated heart failure.

[VNTR3' polymorphism of apoliproprotein B gene in obese people]

Apolipoprotein B (apo B) is the major component of LDL, VLDL and chylomicrons. Variations of lipid concentrations in obese people result from obesity, nutritional and genetic factors. Many genetic polymorphisms of the apo B have been described, associated with variation of lipid concentrations. The aim of the present study was to assess the effect of VNTR3' polymorphism of the apoB gene on lipid and lipoprotein concentrations in overweight subjects. 234 unrelated outpatients (160 women and 74 men, aged 39.3 y 10.5; BMI: 32.8 kg/m2 4.7) were recruited. Using the polymerase chain reaction followed by electrophoresis in polyacrylamide gels, 15 different alleles have been identified. Among them four have been observed less than 5 times in our study. Alleles with 21, 25, 35 and 42 repeats have been observed once. The most frequent is VNTR36 allele (38%), followed by alleles 34, 30, 48, and 46 repeats whose frequencies are 20, 9, 8, and 7% respectively. The possible association between alleles of the VNTR3' of the apoB and anthroprometric and lipid variables was examined. Subjects with 50 repeat allele had significantly higher BMI, and subjects with 32 repeat allele had significantly higher HDL-C and ApoAI levels. Our study confirms in the obese subjects, results published in the general litterature, and shows that the apoB has an important role in the metabolism of plasma lipids and most particulary its gene variants.

[Multiple keratoacanthoma centrifugum marginatum]

INTRODUCTION

Keratoacanthoma centrifugum marginatum is a rare variety of commonly isolated keratoacanthoma. The size of the lesions and prolonged evolution often raise therapeutic problems.

CASE REPORT

A 63-year-old man presented with multiple keratoacanthoma centrifugum marginatum evolving for 6 months and predominating on the lower limbs. Because of the multiplicity and size of the lesions, the patient was treated at acitretine at the dose of 1 mg/kg/day for five months, leading to the regression of all the lesions.

DISCUSSION

Keratoacanthoma centrifugum marginatum has rarely been reported in the literature. Our observation remains exceptional in the multiplicity and size of the lesions. The efficacy of retinoids, previously reported in the treatment of solitary giant keratoacanthoma, multiple keratoacanthoma and keratoacanthoma centrifugum marginatum, was demonstrated even in this handicapping form of keratoacanthoma.

Activation of cardiac endothelium as a compensatory component in endotoxin-induced cardiomyopathy: role of endothelin, prostaglandins, and nitric oxide

BACKGROUND

In view of growing evidence of an important endothelial paracrine regulation of cardiac function, the present study investigated the role of cardiac endothelium-derived endothelin-1 (ET-1), prostaglandins, and nitric oxide (NO) during endotoxin-induced cardiomyopathy in rabbits.

METHODS AND RESULTS

Immunohistochemical studies showed a marked transient coinduction of the inducible isoforms of NO synthase (NOS-2) and cyclooxygenase (COX-2) in endocardial endothelium and coronary arteriolar endothelium of hearts 12 hours after intravenous administration of lipopolysaccharide (LPS+12h); staining for both isoforms was much weaker 24 hours later (LPS+36h). Nitrotyrosine localization was similar to that of NOS-2, suggesting a NOS-2-related endothelial formation of peroxynitrite in septic hearts. Contractile performance of papillary muscles was depressed in both LPS-treated groups. In the LPS+12h group, however, isometric twitches were significantly prolonged (482+/-14 versus 420+/-14 ms in the saline-treated group, P<0.005). This twitch prolongation was completely reversed by simultaneous administration of BQ-123 and indomethacin to block endogenous ET-1 and prostaglandins, respectively. In addition, in the LPS+12h group, myocardial inotropic responsiveness to exogenous ET-1 was enhanced (P<0.01).

CONCLUSIONS

Cardiac endothelial activation and myocardial sensitization to endothelium-derived mediators may be part of an adaptive response in the early (12 hours) stages of septic cardiomyopathy.

[Successful endovascular embolization in the vertebral artery after failed surgery in a patient with severe hemorrhagic shock]

Injury of the vertebral artery following penetrating trauma is rare and treatment is usually a surgical double ligation. We report a case of a 19-year old man, suffering from potentially fatal haemorrhage related to a penetrating trauma of the left vertebral artery. After failure of surgery, bleeding has been successfully stopped by endovascular embolization. The patient did not suffer any ischaemic cerebral complication and was discharged from intensive care unit 24 hours later.

[Vitamin E: structure, metabolism, and functions]

Vitamin E is a generic term denoting eight different isomers among which alpha-tocopherol is the most important and most active. Vitamin E metabolism is closely linked to lipids during intestinal absorption, plasma secretion and transport, and tissue uptake. It is a key compound involved in many physiological processes, such as neurological and immune functions. The most common role of vitamin E is its antioxidant effect, protecting molecules and tissues against the deleterious effect of free radicals. Vitamin E also contributes to the stabilization of biological membranes. In addition, it intervenes in the regulation of several enzymes and probably has impact on gene expression. Advancing knowledge about vitamin E has been achieved with high performance liquid chromatography, making assay accessible to many laboratories, and the use of deuterated derivatives to better apprehend its metabolism. Certain issues remain unresolved concerning the molecular basis of vitamin E's mechanism of action and the exact nature of metabolic dysfunction leading to the clinical manifestations of severe vitamin E deficiency.

[Vitamin E deficiency: risk factor in human disease?]

Oxidative stress is suspected to intervene in certain chronic diseases. Much research has been devoted to the relationship between vitamin E, a major lipid-soluble antioxidant, and certain widespread diseases. Experimental and epidemiological proof supports a protective effect of vitamin E in a number of pathological processes such as coronary heart disease, cancer, cataract, diabetes mellitus, and Alzheimer disease. Randomized clinical trials have not confirmed a beneficial effect of vitamin E supplementation on the progression of these diseases. Certain methodological biases could however have affected these studies, explaining conflicting results. These biases include inaccuracy of vitamin E intake estimates and changes in eating habits during the course of the survey. An insufficient supplementation period using an insufficient dose and inclusion of aged and high-risk patients are the main limitations of the reported clinical trials. Large scale randomized clinical trials including healthy and low-risk subjects, along with prolonged administration of high-dose natural vitamin E, associated with synergetic compounds, and testing on morphological or biological features, will allow a better understanding of the relationship between vitamin E and chronic diseases.

[Vitamin E deficiency. Etiopathogenesis, clinical, histopathologic, and electrical features, and main etiologies]

Vitamin E deficiency is frequently observed in human pathology. In most cases, deficiency is moderate and asymptomatic. Severe deficiency is rare and presents as a progressive neurological syndrome including cerebellar ataxia and posterior cord injury. Neuropathological and electrophysiological features confirm spinocerebellar degeneration. The pathophysiology of vitamin E deficiency nervous dysfunction is still unknown. Oxidative alterations due to the lack of the main lipid-soluble antioxidant could be involved. A few causes of vitamin E deficiency are recognized (malnutrition, impaired lipid absorption, specific anomaly of hepatic or intestinal secretion of vitamin E, excessive endogenous consumption), but diseases associated with vitamin E deficiency are numerous and divers. Symptomatic severe deficiency is constantly observed in ataxia with vitamin E deficiency and abetalipoproteinemia. Intestinal, hepatobiliary, and pancreatic diseases are often associated with more or less marked deficiency. Other pathological circumstances such as malnutrition, alcoholism, hemolytic anemia, renal failure and hemodialysis could be associated with moderated and asymptomatic vitamin E deficiency. Oral or regular administration of high-dose vitamin E is required for patients with symptomatic severe deficiency. An adapted supplementation is recommended for patients with a marginal vitamin E status.

Sepsis is associated with reciprocal expressional modifications of constitutive nitric oxide synthase (NOS) in human skeletal muscle: down-regulation of NOS1 and up-regulation of NOS3

OBJECTIVE

To study the expression (mRNA and protein) and activity of the constitutive isoforms of nitric oxide synthase (NOS1 and NOS3) in a skeletal muscle of septic patients.

DESIGN

Prospective study.

SETTING

An adult trauma/surgical intensive care unit in an urban teaching hospital.

PATIENTS

Sixteen septic patients and 21 controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Samples of the rectus abdominis muscle were obtained during surgical procedure. NOS mRNA, protein, and activity were detected by reverse-transcriptase polymerase chain reaction, Western blot, and the conversion of [3H]L-arginine to [3H]L-citrulline, respectively. The main results of this study are as follows: a) Levels of NOS1 mRNA and protein were significantly higher than those of NOS3 in the rectus abdominis muscle of control patients; b) NOS1 expression was down-regulated in septic patients, whereas NOS3 was up-regulated; c) these modulations were associated with a reduction in constitutive NOS activity; and d) modifications of NOS1 and NOS3 protein expression were correlated significantly with the severity of sepsis, assessed by the Simplified Acute Physiology Score II.

CONCLUSIONS

Sepsis induces reciprocal expressional modifications of NOS1 and NOS3 in human skeletal muscle, which decreases muscular constitutive NOS activity. These modifications may have implications for muscle impairment in septic patients.

Prolactin levels in Behçet's disease: no correlation with disease manifestations and activity

OBJECTIVE

To assess prolactin level and its possible role in the pathogenesis and disease expression of patients with Behçet's disease (BD).

MATERIALS AND METHODS

Twenty-eight patients with the diagnosis of Behçet's disease were selected. They all fulfilled the international criteria for BD. The control group consisted of 17 males and 6 females. Patients are divided into subgroups according to the clinical and paraclinical characteristics such as disease duration, ocular, articular and neurological involvement. Serum prolactin was measured by ELISA using Merck Kits on a Maggia 7000 Analyser. The normal range in males was<17ng/ml in males and<18ng/ml in females. The mean PRL level in each group and subgroup was calculated and compared with Student's t test.

RESULTS

The mean prolactin level in the BD group (mean=13.76, SD=6.82), was higher than in the control group (mean=10.13, SD=5.46) with no statistically significant difference. The mean prolactin levels in all subgroups of patients with BD were higher than normal, but no statistically significant difference was shown between these subgroups.

CONCLUSION

Hyperprolactinemia occurred in a small number of patients with BD and its significance remained unclear. Serum PRL level did not correlate with disease manifestations and activity.

Phosphorylation-dependent alteration in myofilament ca2+ sensitivity but normal mitochondrial function in septic heart

The subcellular mechanisms responsible for myocardial depression during sepsis remain unclear. Recent data suggest a role for impaired energy generation and utilization, resulting in altered contractile function. Here, we studied the energetic and mechanical properties of skinned fibers isolated from rabbit ventricle in a nonlethal but hypotensive model of endotoxemia. Thirty-six hours after lipopolysaccharide (LPS) injection (in the presence of altered myocardial contractility), mitochondrial respiration, coupling between oxidation and phosphorylation, and creatine kinase function were similar in preparations from endotoxemic (LPS) and control animals. The maximal Ca2+-activated force was similar in LPS and control preparations. However, the Ca2+ concentration corresponding to half-maximal force (pCa50, where pCa = -log10[Ca2+]) was 5.55 +/- 0.01 (n = 11) in LPS fibers versus 5.61 +/- 0.01 (n = 10) in control fibers (p < 0.01). Both protein kinase A (PKA) and alkaline phosphatase treatment led to the disappearance in the difference between control and LPS pCa50 values. Incubation of control fibers with the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP) did not change the Ca2+ sensitivity after subsequent skinning, whereas isoproterenol decreased pCa50 from 5.62 +/- 0.01 to 5.55 +/- 0.01 (p < 0.01). These data suggest that during sepsis, cardiac mitochondrial and creatine kinase systems remain unaltered, whereas protein phosphorylation decreases myofibrillar Ca2+ sensitivity and may contribute to the depression of cardiac contractility.

Cardiac contractile impairment associated with increased phosphorylation of troponin I in endotoxemic rats

The subcellular mechanisms underlying intrinsic myocardial depression during sepsis remain poorly defined, in particular the relative roles of altered intracellular Ca2+ transients versus changes in myofilament properties. We studied contractile function of cardiac myocytes isolated 12 h after induction of endotoxemia (5 mg/kg intravenous E. coli lipopolysaccharide [LPS]) in conscious rats. Cardiomyocytes from LPS-injected rats had depressed twitch shortening compared with control cells (4.10.2% versus 7.80.3%; P2+ transients (peak indo-1 ratio 1.130.02 versus 1.120.02; P = NS). Contractile depression was unaffected by inhibitors of nitric oxide synthase. Steady-state myofilament response to Ca2+, assessed by tetanization of intact cells over a range of [Ca2+], was reduced significantly in the LPS group (P2+ was unaffected by isoproterenol (3 nmol/L) in endotoxemic cells, whereas there was a rightward shift in control cells. A reduction in myofilament response to Ca2+ is the major determinant of intrinsic cardiac depression in systemic endotoxemia. This condition appears to be related to an increase in myocardial troponin I phosphorylation.

Muscular contractile failure in septic patients: role of the inducible nitric oxide synthase pathway

Skeletal muscle failure is a frequent manifestation of sepsis that affects prognosis and rehabilitation by impairing respiration and ambulation. Animal studies have shown that the inducible NO synthase (NOS2) is expressed in skeletal muscles during sepsis, likely affecting muscular function, by promoting the formation of the strong oxidant peroxynitrite. In contrast, whether human skeletal muscle expresses a functional NOS2 in similar conditions is unknown. We studied NOS2 expression (mRNA and protein) and activity and its role in contractile function in samples from rectus abdominis muscle obtained during surgical procedure in 16 septic patients and in 21 controls. Peroxynitrite formation was detected by immunohistochemical detection of nitrotyrosine residues. The main results of this study are as follows: (1) A significant increase in NOS2 mRNA, protein, and activity was found in muscles from septic patients, the expression of NOS2 protein positively correlating with sepsis severity. (2) Contractile force was significantly lower in septic than in control muscles. This phenomenon was not reverted by muscle incubation ex vivo with the NOS inhibitor L-NMMA, indicating that NO was not involved in force reduction at the time of biopsy. (3) NOS2 expression in skeletal myocytes was strongly co-localized with nitrotyrosine, revealing muscular peroxynitrite generation during the septic process, before the muscle was biopsied. Exposure of control muscles to an amount of peroxynitrite similar to that generated in septic muscles during the septic process resulted in a nonreversible reduction in force generation. These results suggest that NOS2 could be involved in the decreased muscular force of septic patients via the local generation of peroxynitrite.

Vitamin E and coronary heart disease in Tunisians

BACKGROUND

Vitamin E (VE) is thought to be effective in preventing atherosclerosis. However, to date no consistent relationship has been identified between VE and coronary heart disease (CHD). This study was designed to assess the degree of association between VE and CHD in a sample of the Tunisian population.

METHODS

Sixty-two angiographically confirmed coronary atherosclerotic patients and 65 age- and sex-matched controls were included. VE was measured in plasma and in the LDL fraction by HPLC. Cholesterol, triglycerides, and phospholipids were measured by enzymatic methods.

RESULTS

A trend toward a meaningful decrease of plasma VE was observed in affected patients compared with controls (P: = 0.06). VE concentrations standardized for cholesterol and lipid concentrations were significantly lower (P: <0.02) in coronary patients than in controls (4.35 +/- 1.03 vs 4.82 +/- 1.23 mmol/mol for cholesterol-adjusted VE and 2.35 +/- 0.56 vs 2.66 +/- 0.65 mmol/mol for lipid-adjusted VE, respectively). In the LDL fraction, only cholesterol-standardized VE was significantly lower in cases than controls (3.84 +/- 1.13 vs 4.41 +/- 1.16 mmol/mol). This association between VE and CHD remained unchanged independent of age, sex, smoking habit, hypertension, and diabetes. In CHD patients, lower lipid-adjusted VE was associated with enhanced LDL susceptibility to oxidation but without alteration of the serum fatty acid profile.

CONCLUSIONS

These results support the hypothesis that VE plays a role in preventing atherosclerosis.

[Dermatomyositis and nasopharyngeal carcinoma: 3 cases]

BACKGROUND

Nasopharyngeal carcinoma is a common cancer in Tunisia with an estimated incidence of 1.8/100,000. The tumor shows a characteristic association with paraneoplastic syndromes.

CASE REPORTS

We report three cases of histologically proven dermatomyositis associated with nasopharyngeal carcinoma in patients aged 40, 24 and 65 years. In all cases, the course of the paraneoplastic syndrome ran parallel to the nasopharyngeal carcinoma.

DISCUSSION

Dermatomyositis is one of the numerous paraneoplastic syndromes associated with nasopharyngeal carcinoma. Systematic examination of the nasopharynx is required in case of dermatomyositis.

Sequential changes in autonomic regulation of cardiac myocytes after in vivo endotoxin injection in rat

We report that in vivo injection of endotoxin (EDTX, 6 mg. kg(-)(1)) induces cardiovascular alterations in rats that closely mimic the clinical situation, as assessed by in vivo hemodynamic measurements in anesthetized and conscious, chronically instrumented animals. The patch-clamp technique was used to characterize the L-type calcium current (I(Ca)) and its autonomic regulation in isolated cardiac myocytes. The density of I(Ca) progressively decreased at 12 and 36 h after EDTX injection. However, the dihydropyridine (+/-)Bay K 8644 (100 nM) enhanced I(Ca) to levels similar to those in control and EDTX-treated myocytes. In addition, the net stimulatory effect of a beta-adrenergic agonist (isoproterenol) on I(Ca) was increased 12 h after EDTX injection. This change in the beta-adrenergic effect declined 24 h later. The potentiation in the beta-adrenergic stimulation of I(Ca) was mimicked by L858051 (10 microM), a direct activator of adenylyl cyclase, but not by IBMX (200 microM), a phosphodiesterase inhibitor. Besides, the antiadrenergic effect of acetylcholine on I(Ca) was unchanged 12 h after EDTX injection, but increased 36 h after EDTX injection. These results support the hypothesis that time-dependent changes in the adenylyl cyclase pathway in cardiac myocytes may contribute, via the autonomic regulation of I(Ca), to the severity of myocardial dysfunction during sepsis.

Potential paracrine role of the pericardium in the regulation of cardiac function

OBJECTIVE

Both coronary and endocardial endothelium regulate cardiac contractile function via paracrine pathways. We investigated whether pericardial fluid (PF) and pericardial mesothelial cells (PMC) could exert a similar paracrine action.

METHODS

Both PF and PMC were extracted from sheep pericardial space. Endothelin-1, prostaglandins and atrial natriuretic factor were measured in PF in vivo. In the other hand, PMC were grown on T-75 flasks and microcarrier beads to investigate endothelin-1, nitric oxide and prostaglandin pathways in vitro. In addition, effects of PF and PMC effluent were tested on adult rat cardiac myocyte contraction in vitro.

RESULTS

In vitro, cultured PMC expressed endothelin-1 mRNA but not the endothelial nitric oxide synthase III, and released endothelin-1 and prostaglandins. Both PF and cultured PMC superfusate induced a potent, rapidly reversible decrease in the shortening of isolated rat cardiac myocytes. This effect was not associated with changes in intracellular calcium. In vivo, prostaglandins, atrial natriuretic factor and endothelin were present in PF. A greater concentration of atrial natriuretic factor was present in PF than in serum, suggesting molecular diffusion from the myocardium to PF. Preliminary results show that the instillation of vasoactive agents into the pericardial space of dogs rapidly alter coronary and systemic vascular tone, consistent with a molecular diffusion of these substances from PF into the myocardium and circulation.

CONCLUSIONS

In addition to its mechanical role, the pericardium may contribute to the integration and the regulation of cardiovascular function via a paracrine mechanism.

Intravenous almitrine bismesylate reversibly induces lactic acidosis and hepatic dysfunction in patients with acute lung injury

BACKGROUND

Intravenous almitrine, which augments hypoxic pulmonary vasoconstriction, is used for short-term improvement of arterial oxygenation. However, recent research has suggested a potentially harmful effect on lactate metabolism and hepatic function.

METHODS

Arterial oxygenation, hemodynamic parameters, plasma lactate, and hepatic function were monitored prospectively in 25 patients with acute lung injury (defined as a ratio of arterial oxygen pressure to inspiratory oxygen fraction < or = 150 mmHg) who where treated with intravenous almitrine. In 21 of 25 patients, acute lung injury was related to primary lung lesions, including pneumonia, postcardiosurgical atelectasis, and lung contusions.

RESULTS

Intravenous almitrine increased the ratio of arterial oxygen pressure to inspiratory oxygen fraction from 93 +/- 33 mmHg to 207 +/- 107 mmHg (mean +/- SD). In eight patients (three men), the plasma lactate concentration increased by an average of +3.5 +/- 1.8 mM, and the pH and bicarbonate concentration both decreased during the first 24 h of treatment. In this group of patients, the total bilirubin concentration was elevated before almitrine administration, and the results of other hepatic function tests, such as aspartate aminotransferase, alanine aminotransferase, and prothrombin time, were altered by almitrine administration. Therefore, intravenous almitrine was discontinued. Lactic acidosis and hepatic dysfunction improved. In the other 17 patients (14 men), the plasma lactate concentration and the hepatic function tests remained unaltered during intravenous almitrine therapy for > 60 h. Univariate and multivariate analyses revealed that an abnormal plasma concentration of total bilirubin before almitrine administration and female gender were the two factors significantly linked with lactic acidosis during almitrine infusion.

CONCLUSIONS

This study confirms that intravenous almitrine greatly improves arterial oxygenation in patients with acute lung injury but may also induce lactic acidosis and hepatic dysfunction. The coexistence of lactic acidosis and hepatic dysfunction in the same patients strongly suggests that the liver is the primary source of intravenous almitrine-induced lactic acidosis.

Electrophysiology and nerve biopsy: comparative study in Friedreich's ataxia and Friedreich's ataxia phenotype with vitamin E deficiency

The authors report a comparative study of peripheral nerve conductions and nerve biopsy and somatosensory evoked potentials between 15 patients with Friedreich's ataxia and 15 patients with Friedreich's ataxia phenotype with selective vitamin E deficiency. The patients in the two groups are of similar age, age of onset, and clinical phenotype. Peripheral motor nerve action potential amplitude, and conduction velocities are within normal ranges in the two groups. In the Friedreich's ataxia group there is an early and severe peripheral sensory axonal neuronopathy, characterised by an important reduction of the amplitude of sensory action potential, and important loss of myelinated fibres with complete disappearance of large myelinated fibres without any regenerative process. In the Friedreich's ataxia phenotype with selective vitamin E deficiency group there is slight-to-moderate axonal sensory neuropathy with normal to moderate decrease of large myelinated fibre density and important regeneration in nerve biopsy. Somatosensory evoked potentials are markedly involved in the two groups asserting a severe involvement of somatosensory pathway in lumbar, thoracic and cervical spinal cord. These findings suggest that the pathological mechanism involved in the two diseases are different: central peripheral axonopathy in Friedreich's ataxia and central distal axonopathy in Friedreich's ataxia phenotype with selective vitamin E deficiency.

Paracrine regulation of cardiac myocytes in normal and septic heart

A paracrine pathway for the regulation of cardiac contractile function by nonmuscle cells is documented in the heart. Coronary and endocardial endothelium release several diffusible agents, such as prostaglandins, endothelin-1, and nitric oxide, with an action on cardiac myocyte function. Cardiac diseases involving an immune or inflammatory mechanism, such as endotoxic shock, are now seen as conditions in which cross-talk between different cell types in the heart is clearly implicated. The potential biological relevance of inducible nitric oxide synthase in the myocardium, and the subsequent production of nitric oxide has been proposed as a mechanism of the cardiac depression observed in septic shock. In addition to cardiac myocytes, activated microvascular endothelial cells and cardiac endothelial cells may contribute to nitric oxide generation and, ultimately, to the depression of myocardial contractile activity during sepsis. This article reviews the local intercellular communication between cardiac myocytes and endothelial cells in the normal heart and discusses some of the mechanisms potentially claimed to depress heart function in sepsis.

[Reference values of urinary orotic acid in a healthy Tunisian population]

BACKGROUND

Orotic acid (OA) is an intermediary metabolite of pyrimidine synthesis. An elevation of urinary orotic acid excretion has been described in congenital defect of the urea cycle enzymes and in primary orotic aciduria. Several techniques have been used to measure OA and many reference values are published without considering age and sex.

POPULATION AND METHODS

The reference values of urinary OA excretion, expressed in mumol/mmol of creatinine, are reported in a healthy Tunisan population using a colorimetric method. The study included 20 men and 20 women (age = 31 +/- 11 years) and 30 children aged from 3 days to 8 years.

RESULTS

There was a significant increase (P < 0.01) of urinary OA excretion in women (4.38 +/- 1.35) compared to men (3.26 +/- 0.80) and of children (5.03 +/- 1.14) compared to adults (3.82 +/- 1.24). Urinary OA excretion was significantly higher among children aged less than 1 year compared to older children.

CONCLUSION

It is necessary for every laboratory practicing this kind of exploration to have its own norms which depend on both age and sex.