Case of triple endocarditis caused by Rothia dentocariosa and results of a survey in France

This is the first case of endocarditis in which Rothia dentocariosa was cultured from three affected valves. In addition, the records of two microbiology laboratories in France showed that R. dentocariosa was rarely involved in severe infection and that positive blood cultures were not associated with endocarditis.

Trophic effect of human pericardial fluid on adult cardiac myocytes. Differential role of fibroblast growth factor-2 and factors related to ventricular hypertrophy

Pericardial fluid (PF) may contain myocardial growth factors that exert paracrine actions on cardiac myocytes. The aims of this study were (1) to investigate the effects of human PF and serum, collected from patients undergoing cardiac surgery, on the growth of cultured adult rat cardiac myocytes and (2) to relate the growth activity of both fluids to the adaptive changes in overloaded human hearts. Both PF and serum increased the rate of protein synthesis, measured by [14C]phenylalanine incorporation in adult rat cardiomyocytes (PF, +71.9 +/- 8.2% [n = 17]; serum, +14.9 +/- 6.5% [n = 13]; both P < .01 versus control medium). The effects of both PF and serum on cardiomyocyte growth correlated positively with the respective left ventricular (LV) mass. However, the magnitude of change with PF was 3-fold greater than with serum (P < .01). These trophic effects of PF were mimicked by exogenous basic fibroblast growth factor (FGF2) and inhibited by anti-FGF2 antibodies and transforming growth factor-beta (TGF-beta), suggesting a relationship to FGF2. In addition, FGF2 concentration in PF was 20 times greater than in serum. On the other hand, the LV mass-dependent trophic effect, present in both fluids, was independent of FGF2 concentration or other factors, such as angiotensin II, atrial natriuretic factor, and TGF-beta. These data suggest that FGF2 in human PF is a major determining factor in normal myocyte growth, whereas unidentified LV mass-dependent factor(s), present in both PF and serum, participates in the development of ventricular hypertrophy.

Inhibition of myocardial crossbridge cycling by hypoxic endothelial cells: a potential mechanism for matching oxygen supply and demand?

Previous studies have shown that cardiac endothelial cells release substances that influence myocardial contraction. Since PO2 is an important stimulus that modulates endothelial function, we investigated the effects of acute moderate hypoxia and reoxygenation on the release of cardioactive factors by endothelial cells. Endothelial cells cultured from several vascular beds were superfused with normoxic (equilibrated with room air; PO2, approximately 160 mm Hg) or hypoxic (PO2, 40 to 50 mm Hg) physiological buffer solution, and the superfusates were reequilibrated to a PO2 of approximately 160 mm Hg and then tested for their effects on various myocardial assays. Endothelial cell viability and buffer ionic composition were unaltered after the superfusion procedures. The superfusates of hypoxic endothelial cells induced rapid, potent, reversible inhibition of isolated cardiac myocyte contraction without reducing cytosolic Ca2+ transients. This activity was not lost after heating (95 degrees C) and was present in low molecular weight (Mr, <500) superfusate fractions. Hypoxic endothelial superfusate reduced unloaded shortening velocity of human skinned soleus muscle fibers. It markedly depressed in vitro actin motility over cardiac myosin and reduced the rate of actin-activated cardiac myosin ATPase activity but had no effect on corresponding smooth muscle myosin assays. Reoxygenation of hypoxic endothelial cells resulted in loss of this inhibitory activity. These data indicate that cultured endothelial cells respond to acute moderate hypoxia by releasing an unidentified substance(s) that inhibits myocardial crossbridge cycling, independent of Ca2+ or other second messenger signaling pathways. Such a mechanism could have important implications for the regulation of oxygen supply-demand balance in the heart and be relevant to conditions such as myocardial hibernation.

Endocardial endothelial dysfunction and heart failure

Like vascular endothelium, the EE plays a role in transendothelial transport, in coagulant and thrombotic processes, and in interactions with inflammatory cells. In addition, EE is involved in the modulation of cardiac performance of subjacent myocardium. EE dysfunction includes insufficient as well as excessive performance of any of its multiple functions. Dysfunction can progress from a disturbed modulation of myocardial performance and an imbalance in the release of growth factors to changes in EE cytoskeletal organization, with concomitant changes in transendothelial permeability, and in extreme cases, to loss of endothelial integrity and frank denudation. Structural and functional impairment of EE and of endocardial interstitial cells may be primary or secondary to the disease. Mechanical stress, various hormones and cytokines can initiate EE dysfunction. EE dysfunction may influence the development of cardiac failure in endo(myo)cardial fibrosis (Loeffler's endocarditis and carcinoid syndrome) and in dilated cardiomyopathy. Although Bouillaud, in 1836, was referring to endocarditis when stating: (quote: see text) his statement may presently find a much broader field of applicability in cardiology.

The cardiac endothelium: cardioactive mediators

Endothelial cells within the heart release a number of substances that modulate myocardial contractile function. These agents include nitric oxide, endothelin, prostanoids, adenylpurines, and other substances that have so far been characterized only in bioassay studies. A notable feature of many of these agents is that they influence contractile behavior predominantly by modifying cardiac myofilament properties rather than altering cytosolic Ca2+ transients. A consequence of this subcellular action is often a disproportionate effect on myocardial relaxation and diastolic tone. The paracrine modulation of cardiac myocyte function by endothelial cell factors is likely to be an important mechanism contributing to the overall regulation of cardiac contractile function, both physiologically and in pathological states.

[Zincemia, cupremia and infection in malnourished children]

BACKGROUND

Serum copper and zinc levels are decreased in malnourished and infected children. The role of either malnutrition or infection remains undetermined.

POPULATION AND METHODS

Serum zinc and copper concentrations were measured by atomic absorption spectrophotometry in 31 malnourished infants aged 1 to 26 months and 28 eutrophic infants aged 3 to 22 months. Fourteen infants of the first group and 10 of the second were infected at the time of study.

RESULTS

Serum zinc and copper levels were significantly decreased in infants with malnutrition (zinc: 66 +/- 32 micrograms/dl and copper: 81 +/- 51 micrograms/dl versus 108 +/- 26 and 185 +/- 21, respectively, in eutrophic infants) (p < 0.001). These levels were still lower in those malnourished infants who were infected (zinc: 49.5 +/- 18 micrograms/dl and copper: 63.5 +/- 37 micrograms/dl versus 81.56 +/- 35 and 94 +/- 56 in non infected patients) (p < 0.02).

CONCLUSIONS

Infection increases the risk of low serum zinc and copper concentrations seen in malnourished children. This factor must be taken in account when treating malnutrition.

Comparison between endocardial and great vessel endothelial cells: morphology, growth, and prostaglandin release

The release of vasoactive mediators by vascular (VEC) and endocardial endothelial cells (EEC) has not been directly compared. In this study, in vitro morphological and cell growth characteristics and the rate of prostanoid release were compared in cultured sheep endothelial cells from great vessels (VEC; pulmonary artery and aorta) and endocardium (EEC; right and left ventricles) harvested from the same animals. Morphologically, in flasks, VEC demonstrated the classic cobblestone pattern, whereas EEC developed numerous cytoplasmic interdigitations and overlaps. Rate of cell proliferation was greater for EEC than for VEC (P < 0.05): doubling time was shorter for EEC (34 +/- 3 h) than for VEC (45 +/- 5 h). Under static (no-flow) conditions, in response to arachidonic acid and calcium ionophore A-23187, the rate of prostacyclin (PGI2) and prostaglandin E2 release by VEC and EEC was not different. In contrast, in response to flow and acute hypoxia (O2 tension = 35 Torr), the rate of PGI2 release was greater in EEC than in VEC (P < 0.0001). After 2 h of perfusion, the rate of PGI2 release was 19-fold greater for EEC than for VEC during normoxia and 34-fold greater during hypoxia. Thus our study showed anatomic site of origin-dependent heterogeneity in prostanoid release between VEC and EEC. Endocardial endothelium is a greater source of PGI2 than great vessel endothelium; in vivo, endocardial endothelial PGI2 may inhibit local platelet aggregation and modulate downstream vascular tone.

Novel cardiac myofilament desensitizing factor released by endocardial and vascular endothelial cells

BACKGROUND

Recent studies suggest that both endocardial endothelium and coronary vascular endothelium influence myocardial contraction, but the mediators responsible and their mechanisms of action are not well defined.

METHODS AND RESULTS

We investigated the effects of cultured endocardial endothelial and vascular endothelial cell superfusate on contraction and intracellular calcium transients of isolated rat cardiac myocytes. Endothelial cell superfusate induced a potent negative inotropic effect, with a rapid reversible decrease in myocyte twitch amplitude, earlier twitch relaxation, and a significant increase in diastolic length. This effect was not associated with significant changes in intracellular calcium or pH; was not attributable to nitric oxide, prostanoids, cGMP, or protein kinase C activation; and did not involve pertussis toxin-sensitive G proteins. The activity was stable at 37 degrees C for several hours, was not destroyed by protease treatment, and was found in low-molecular-weight (<< 1 kD) superfusate fractions.

CONCLUSIONS

These data suggest the tonic release by endothelial cells of a novel, stable factor that acts predominantly by reducing the response of cardiac myofilaments to calcium (ie, "desensitizes" them). This "desensitizing factor" could rapidly modulate cardiac contraction-relaxation coupling and diastolic tonus and exert distant effects because of its stability.

Paracrine effects of endocardial endothelial cells on myocyte contraction mediated via endothelin

Endocardial endothelium is reported to modulate myocardial contraction by releasing diffusible factors, but the nature of the agent(s) responsible is unknown. In the present study we investigated the potential role of endothelin in these effects. Cultured sheep endocardial endothelial cells were found to express endothelin-1 mRNA and to release endothelin-1 into superfusing solution. This superfusate induced positive inotropic effects in isolated rat cardiac myocytes, associated with an increase in the cytosolic Ca2+ transient. Similar positive inotropic effects were induced by vascular endothelial cell superfusate as well as by synthesized endothelin-1, administered at concentrations similar to those present in the superfusate. Incubation of endocardial endothelial cell superfusate with endothelin-1-specific antiserum reduced the free endothelin-1 concentration to undetectable levels and abolished both the positive inotropic effect and the rise in cytosolic Ca2+. These findings indicate that endocardial endothelial cells may modulate myocardial contraction in part through the release of endothelin-1 and suggest that endocardial as well as vascular endothelium could exert potent paracrine effects on myocardium.

Right and left ventricular cultured endocardial endothelium produces prostacyclin and PGE2

The endothelium profoundly affects subjacent vascular smooth muscle function. An analogous relationship between endothelial endocardial cells (EEC) and the myocardium is suggested by Brutsaert et al.'s observation that EEC modulate the contractility of subjacent myocardium. Prostanoids are a major product by which vascular endothelium affects smooth muscle, but similar prostanoid production by EEC has not been described. To determine whether both right and left ventricular EEC produce prostacyclin (PGI2) and prostaglandin E2 (PGE2), ovine EEC were cultured. EEC prostanoid production was measured under basal conditions and after stimulation with arachidonic acid or calcium ionophore A23187. EEC from both ventricles demonstrated sustained prostacyclin and PGE2 production. Prostacyclin production was 10 times greater than PGE2. These results suggest that endocardial prostanoid production could act both locally, to modulate platelet and myocardial function, and distally, on downstream vascular tone.

[Atrial natriuretic factor in men]

The atrial natriuretic peptide (ANP) is rapidly secreted in case of acute changes in atrial volume and heart rate. Its effects are mainly natriuretic and vasodilator. This hormone is of interest to the anaesthetist because induction of anaesthesia, epidural anaesthesia and administration of morphine all result in changes in ANP plasma concentration.

Sex differences in serum luteinizing hormone and testosterone in the human neonate during the first few hours after birth

Blood was obtained from human male and female neonates within a few minutes after birth, and at intervals thereafter for up to 21 h. Serum LH was substantially higher at birth for boys than girls. For most boys, serum LH fell precipitously during the next hour; serum LH remained low for the remainder of the period sampled in both boys and girls. In girls, serum testosterone was low at birth and remained low for at least 21 h. At birth, serum testosterone in boys was higher than for girls, increased dramatically during the first 3 h after birth, and remained elevated (2 to 3 times higher than for girls) between 3 and 12 h after birth. In newborn human males, a sudden discharge of hypophyseal LH appears to stimulate neonatal secretion of testosterone by the testes. The functional significance of this phenomenon remains to be determined.

[Atrial natriuretic factor]

Although ANF research started 30 years ago, the atrial natriuretic factor (ANF) was only discovered recently (1981). The presence of such a factor has been suspected for many years because of histological and physiological arguments. In 1956, Kish found "dense granules" in the atrial walls of guinea pigs. Gauer and Henry could explain some of their experimental results on diuresis and natriuresis only by suggesting the presence of a third hormonal factor, but neither by the renin-angiotensin system, nor the anti-diuretic hormone. Hall et al. were the first to recognize a link between the granules and water and sodium metabolism. But it was De Bold who published the crucial experiment in 1981: injecting right atrial extracts to anaesthetized rats rapidly induced intense and transitory diuresis and natriuresis. ANF was born, and, at the same time, the concept of the heart as an endocrine gland. Indeed, ANF corresponds to the strict definition of a hormone. It has the following properties: natriuresis and diuresis via an increase in glomerular filtration fraction without any major changes in renal plasma flow; direct vasodilation of the large arteries with only few effects on small arterioles and veins. The stimuli for ANF secretion are mechanical and pharmacological, especially drugs currently used by anaesthetists. Atrial distension is the main mechanical stimulus. An increase in atrial transmural pressure is always followed by a release in ANF, but this effect is not constant for increases in intra-luminal pressure. It is the former pressure gradient alone that reflects the volume of the right atrium, the mechanical stimulus for ANF secretion. Tachycardia, or, more precisely, an increase in the atrial contraction rate, also leads to an important release of ANF. Cardiac nerves are not necessary for this, as demonstrated by studies in heart transplant patients. Only few pharmacological agents have been shown to really stimulate ANF secretion. In rats, morphine has a direct secretory effect, whereas ketamine hydrochloride, diethylether and chloral hydrate do so by increasing the release of catecholamines. The effects of alpha, beta adrenergic agonists and calcium agonists remain controversial. ANF, which has diuretic and vasodilator effects, plays a part, together with the renin-angiotensin system and the anti-diuretic hormone, in blood volume control in mammals. However, it has a special role to play, because it is a rapid release hormone: rapid vascular filling leads to an increase in ANF in less than 1 minute, with a parallel increase in diuresis.

Plasma lipoproteins in infantile visceral leishmaniasis: deficiency of apolipoproteins A-I and A-II

This study describes the plasma lipoprotein system of young children with visceral Leishmaniasis (Kala-azar disease). In addition to the presence of amastigote forms in the sternal aspirates of bone marrow, the patients exhibited fever, anemia, hepatosplenomegaly, various degrees of pancytopenia and a slight liver cytolysis. Patients had normal total cholesterol levels and increased triglyceride levels in the plasma. The concentrations of HDL and LDL were 30% and 50% of these reported for normolipemic subjects, respectively. In contrast, there was a three-fold increase in the concentration of VLDL. The ratio of free to total cholesterol was high; this was further substantiated by electron microscopy of HDL showing the presence of disc-like particles. Quantitative determination of apolipoproteins revealed a three- and seven-fold decrease of apolipoproteins (Apo) A-I and A-II, respectively, whereas Apo B levels were within the normal range. The presence of LP-A-II particles was demonstrated by two-dimensional immunoelectrophoresis in most of the patients' plasma during the acute phase of disease.