Bone resorption in multiple myeloma and in monoclonal gammopathy of undetermined significance: quantification by urinary pyridinium cross-links of collagen

To quantify osseous breakdown in multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), and benign osteoporosis, we measured urinary levels of pyridinium cross-links of collagen in 50 patients with newly diagnosed and untreated MM, 40 patients with MGUS, 40 untreated patients with osteoporotic vertebral fractures, and 64 healthy adults. Ion-paired, reverse-phase high-performance liquid chromatography (HPLC) was used to measure total urinary excretion of pyridinoline (h-PYD) and deoxypyridinoline (h-DPD). Urinary excretion of free immunoreactive deoxypyridinoline (i-DPD) was determined with an enzyme immunoassay. MM patients had significantly (P < .0001) higher levels of h-PYD, h-DPD, and i-DPD than the healthy adults, patients with MGUS, or patients with osteoporosis. The MGUS and osteoporosis groups presented with elevated (P < .05) levels of urinary pyridinium cross-links when compared with healthy controls. In 20 MM patients who subsequently received chemotherapy, the percent changes in i-DPD did not correlate with the changes in the monoclonal protein. In one of three patients experiencing a transition of initial MGUS into stage I MM, i-DPD increased above the upper limit of the normal range. In 13 patients with stable MGUS, i-DPD remained normal in repeated measurements. Based on the upper limits of the normal range, the sensitivity of urinary pyridinium cross-links in stage I and II MM was low (<50%), but it was between 78% (h-DPD) and 93% (i-DPD) in stage III MM. Specificity in patients with MGUS was between 87% (h-PYD) and 97% (h-DPD). In conclusion, determining the urinary excretion of pyridinium cross-links seems to be a promising noninvasive and thus easily repeatable method for evaluating the actual degree of osseous breakdown. Although measurement of pyridinium cross-link levels is not useful in discriminating patients with MGUS from early-stage myeloma patients, determination of i-DPD levels may contribute importantly to clinical guidance, since increased i-DPD levels seem to identify patients who are particularly likely to benefit from osteoclast-inhibiting drugs such as bisphosphonates. The fact that in a number of patients paraprotein concentrations and i-DPD levels did not change in parallel but instead diverged strongly after chemotherapy might explain the observation that bone lesions sometimes progress even in patients who achieve complete remission.

In vitro isolation and cultivation of Cowdria ruminantium under serum-free culture conditions

Three stocks of Cowdria ruminantium, the causative agent of heartwater in domestic ruminants, were propagated in bovine endothelial cells in a serum-free culture medium. The Vosloo, Welgevonden and Senegal stocks were propagated for a period of more than 203, 134, and 43 days, respectively. Two of the C ruminantium stocks (Vosloo and Senegal) were also successfully initiated under serum-free culture conditions. The serum-free medium consisted of a modified HL-1 medium. The Senegal stock was successfully propagated in Dulbecco's modified Eagle's medium nutrient mixture Ham F-12 containing 10 per cent fetal bovine serum.

Some haematological and immunological parameters of farmed deer in Hungary

A haematological survey of farmed fallow deer (Dama dama) and red deer (Cervus elaphus) was carried out. In the winter period the red blood cell (RBC) count was 9.0 x 10(12)/L in adult fallow-does, and 6.1 x 10(12)/L in fawns. The haemoglobin (Hb) level and mean corpuscular volume (MCV) were also significantly (P < 0.05) lower in fawns than in adult fallow deer. In blood samples taken from red deer in different physiological and nutritional periods, the stags showed the lowest mean RBC count in January (4.7 x 10(12/L) and the hinds during lactation (6.3 x 10(12)/L). The mean RBC count of samples taken from a group of red deer fawns at five different times between 1 week and 1 year of age varied between 5.8 and 7.0 x 10(12)/L. In red deer herds the RBC count showed minor variations and the Hb concentration was almost constant in the different periods. The coefficient of correlation between RBC and Hb was 0.66 and 0.58 in fallow deer and red deer, respectively. Studying the blastogenic transformation of lymphocytes by immunological tests, a higher rate of response to non-specific mitogens (Phaseolus vulgaris, PHA; concanavalin A, Con A) was found in farmed deer (> 30%) than in deer captured in the wild and kept under farm conditions for 10 or 13 months (< 20%).

Altered gravitational experience during early periods of life affects the static vestibulo-ocular reflex of tadpoles of the southern clawed toad, Xenopus laevis Daudin

The effects of altered gravitational forces (AGF) on the development of the static vestibulo-ocular reflex (VOR) were investigated in Xenopus laevis tadpoles exposed to hypergravity (1.4g; 3g) or microgravity conditions (German spacelab mission D-2) for 9-10 days. The effects of light conditions during development were also tested by exposing tadpoles to either complete darkness (DD) or 12:12 h light-dark conditions (LD). The static VOR was induced by lateral roll. The efficacy of the VOR circuit after termination of AGF conditions was described by the peak-to-peak amplitude of the sinusoidal VOR characteristics (i.e. amplitude). The static VOR was first observed at stage 41 for both LD and DD tadpoles. Its further development was retarded in the DD tadpoles compared with the LD tadpoles up to stage 48. Microgravity as well as hypergravity exposure caused a significant (P < 0.05, at least) decrease in the static VOR amplitude during the first week after termination of the AGF period. The decreases were 39.4% in the microgravity group, 16.2% in the 1.4g group and 24.9-42.9% in the 3g group compared with the 1g ground-reared siblings at the same developmental stages. The response deficits usually disappeared but persisted for at least 2 weeks in animals whose development was retarded by hypergravity exposure. It is postulated (i) that gravity exerts an important influence on the normal development of the roll-induced static VOR; (ii) that hypergravity exposure decreases the sensitivity of the gravity-sensitive system so that recordings under 1g conditions cause a weaker static VOR; and (iii) that the vestibulo-spinal pathway possesses a higher degree of plasticity than the vestibulo-ocular pathway.

A hypergravity related sensitive period during the development of the roll induced vestibuloocular reflex in an amphibian (Xenopus laevis)

In tadpoles of Xenopus laevis, the effects of an exposure to hypergravity on the development of the roll-induced static vestibuloocular reflex (rVOR) were investigated. Special attention was given to the onset of the 9 or 12 days lasting 3 g period during early life. Recordings of rVOR characteristics for complete 360 degrees rolls of the tadpoles started 24 h after the end of the 3 g period. The rVOR peak-to-peak amplitudes from the 3 g samples recorded at the 2nd and 3rd day after termination of the 3 g exposure agreed with that recorded from the 1 g reared tadpoles for the youngest group, but were reduced by 30% in the older tadpoles. During further development under 1 g condition, the rVOR amplitude of tadpoles with 3 g experience did not change if the 3 g exposure started before the first appearance of the rVOR, but increased if it had started thereafter, albeit on a lower level than that of the 1 g reared siblings. The results support the existence of a sensitive period for the rVOR development, and additionally demonstrate that the period during which the rVOR appeared for the first time is an important milestone for the development of adaptive properties of the underlying neuronal network.

Serum immunoreactive bone sialoprotein as a new marker of bone turnover in metabolic and malignant bone disease

Bone sialoprotein (BSP) is a phosphorylated glycoprotein with a M(r) of 70-80 kDa that accounts for approximately 5-10% of the noncollagenous proteins of bone. Due to its relatively restricted distribution to mineralized tissues, BSP may serve as a potential marker of bone metabolism. Employing a recently developed RIA, serum BSP was measured in 133 healthy subjects, aged 20-80 yr, and in patients with primary hyperparathyroidism (pHPT; n = 26), Paget's disease of bone (PD; n = 14), untreated multiple myeloma (MM; n = 32), and breast cancer with bone metastases (BC; n = 19). Results were compared to clinical and laboratory data, including serum total alkaline phosphatase as a marker of bone formation, and the urinary cross-links pyridinoline (PYD) and deoxypyridinoline (DPD) as markers of bone resorption. In healthy adults, serum BSP values ranged between 5.0-21.6 ng/mL (5-95% interval), with a median of 10.5 ng/mL (total group). In healthy females, a linear correlation was found between serum BSP and age (r = 0.51; P < 0.001), with significantly higher values in postmenopausal than in premenopausal women (13.3 +/- 4.8 vs. 9.0 +/- 3.8; P < 0.01). In the healthy group, BSP values did not change with body mass index, lumbar bone mineral density, serum calcium, serum creatinine, or serum total alkaline phosphatase levels. In contrast, a weak, but significant, correlation was observed between serum BSP and the urinary excretion of PYD and DPD. Compared to those in healthy controls, serum BSP levels were significantly higher in patients with pHPT, PD, MM, or BC (P < 0.01 for all groups). These differences remained after analyses were adjusted for age and sex. In pHPT, serum BSP levels were closely correlated to urinary PYD and DPD (r = 0.87 and 0.83, respectively; P < 0.01), whereas in PD, no correlation was observed between any of the bone markers. Serum BSP levels were highest in patients with MM, and there was a significant difference between early and advanced stages of the disease (30.2 +/- 8.0 vs. 64.3 +/- 6.8; P < 0.01). In a subgroup of 15 patients with metastatic BC, iv bisphosphonate treatment resulted in a rapid reduction of serum BSP levels to 40% of the baseline values within 4 days of treatment. In conclusion, BSP appears to be a sensitive marker of bone turnover, and the present data suggest that its serum levels predominantly reflect processes related to bone resorption.

Expression of epileptiform activity induced by a penicillin focus within the posterior thalamus in the awake rat

Investigations were performed to study the epileptiform activity, induced by a local injection of penicillin (PCN) into the posterior thalamus (pTh) of the awake rat, and to compare it with the epilepsy induced in the same animals 2 weeks later by an injection of PCN into the motor cortex (MC). Using EEG recordings, 1) the distribution of focal cortical activity, and 2) the severity of the epileptiform activity (frequency of focal activity, occurrence and duration of generalized episodes) were analyzed. The focal activity of pTh rats was characterized by two types of potentials: (a) sharp potentials with a spike-like shape that developed during the first hour after PCN injection only in the visual cortex, but in the transition area between the motor and sensory cortex during the last period of epileptiform activity; and (2) large potentials with a wave- or spike-wave-like shape that had their center of focal expression in the transition zone between the motor and sensory cortex. MC rats exhibited only a spike-like potential with or without short-lasting afterdischarges in the homotopic areas of the MC of both hemispheres. During periods with large potentials only, the number of generalized episodes was significantly reduced with respect to those periods with sharp potentials. When the epileptiform activity changed from large to sharp potentials, the interictal frequency increased significantly. It is postulated (a) and a pTh focus activates the lateral and/or the reticular thalamic areas, which, due to their high intrinsic potential for synchronization, cause a self-sustained interictal activity of the large potential type; and (b) that the wave of the large potentials is involved in an anticonvulsive mechanism that reduces the extent of ictal as well as interictal activity.

Comparison of some blood parameters of captured and farmed red deer (Cervus elaphus) hinds

In studies on the adaptation of red deer (Cervus elaphus) to farm conditions, some blood parameters of 3- to 9-year-old captured and farmed hinds were compared. The test variable included blood plasma creatine kinase (CK), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities, the concentrations of glucose, urea, total protein (TP), serum cortisol, haemoglobin (Hb), and the blastogenic transformation of lymphocytes upon stimulation by the nonspecific mitogens Phaseolus vulgaris (PHA) and Concanavalin A (ConA) in the lymphocyte stimulation test (LST). The effects exerted by probiotic preparation (Ascogen) on the same parameters were studied in farmed deer. In hinds that had been kept under farm conditions for 10 months, CK activity was lower (P < 0.05) and blood urea concentration higher (P < 0.001) than at the time of capture, while their blood glucose concentration exceeded (P < 0.01) that of farmed hinds. Hinds treated with Ascogen had lower ALT activity (P < 0.001) and showed a higher increase in PHA-induced blastogenic transformation of lymphocytes than the control hinds.

KATP channel opening does not contribute significantly to the vasodilatory effect of SH-group-containing ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are widely used in the management of hypertension, heart failure, and nephropathy. It has been suggested that ACE inhibitors containing the sulfhydryl group (SH) have an additional effect on KATP channels. To prove this hypothesis, we studied the effects of the SH-containing ACE inhibitors, captopril and zofenopril, on KATP channel opening of bovine coronary arteries and guinea pig thoracic aortas. Bovine coronary arteries were precontracted with the thromboxane A2 analogue, U46619, and guinea pig thoracic aortas were precontracted with phenylephrine and then relaxed with either captopril or zofenopril (n = 8). Inhibition of KATP channel opening with glibenclamide moderately attenuated the zofenopril-induced relaxation of guinea pig thoracic aorta. However, in the bovine coronary arteries, the relaxing effect of both captopril and zofenopril remained uneffected by glibenclamide. In experiments with enalapril (a non SH-containing ACE inhibitor; n = 6) on guinea pig thoracic aortas, no effect on KATP channels could be seen. From our experiments, we conclude that the postulated opening of KATP channels by SH-group-containing ACE inhibitors contributes little to the vasodilation of guinea pig thoracic aortas caused by ACE inhibitors, and that SH groups have no influence upon KATP channels of bovine coronary arteries.

Early development in aquatic vertebrates in near weightlessness during the D-2 Mission STATEX project

Aboard the German-Spacelab-Mission D-2 the project "Gravity Perception and Neuronal Plasticity (STATEX II)" was performed. STATEX is for STATolith EXperiment. Objects were growing tadpoles of the South African Toad (Xenopus laevis D.) and a juvenile cichlid fish (Oreochromis mossambicus). The results give a broader base for the understanding of how environmental stimuli (e.g. linear accelerations) affect the development and function of the gravity perceiving systems in these two vertebrates. These systems are accepted as models for the human vestibulum. Results of experiments in hyper-g (up to 5 g), simulated weightlessness (Fast-rotating-clinostat) and parabolic flights are compared and discussed.

Readaptation of the vestibuloocular reflex to 1g-condition in immature lower vertebrates (Xenopus laevis) after micro- or hypergravity exposure

The effects of altered gravitational conditions (AGC) on the development of the static vestibulo-ocular reflex (VOR) and readaptation to 1g were investigated in the amphibian Xenopus laevis. Tadpoles were exposed to microgravity during the German Space Mission D-2 for 10 days, using the STATEX closed survival system, or to 3g for 9 days during earth-bound experiments. At the beginning of AGC, the tadpoles had not yet developed the static VOR. The main results were: (i) Tadpoles with microgravity- or 3g-experience had a lower gain of the static VOR than the 1g-controls during the 2nd and 5th post-AGC days. (ii) Readaptation to response levels of 1g-reared controls usually occurred during the following weeks, except in slowly developing tadpoles with 3g-experience. Readaptation was less pronounced if, during the acute VOR test, tadpoles were rolled from the inclined to the normal posture than in the opposite test situation. It is postulated that (i) gravity is necessarily involved in the development of the static VOR, but only during a period including the time before onset of the first behavioural response; and (ii) readaptation which is superimposed by the processes of VOR development depends on many factors including the velocity of development, the actual excitation level of the vestibular systems and the neuroplastic properties of its specific pathways.

Double-blind, placebo-controlled study of the long-term efficacy of carvedilol in patients with severe chronic heart failure

BACKGROUND

Clinical trials have shown that beta-adrenergic blocking drugs are effective and well tolerated in patients with mild to moderate heart failure, but the utility and safety of these drugs in patients with advanced disease have not been evaluated.

METHODS AND RESULTS

We enrolled 56 patients with severe chronic heart failure into a double-blind, placebo-controlled study of the vasodilating beta-blocker carvedilol. All patients had advanced heart failure, as evidenced by a mean left ventricular ejection fraction of 0.16 +/- 0.01 and a mean maximal oxygen consumption of 13.6 +/- 0.6 mL.kg-1.min-1 despite digitalis, diuretics, and an angiotensin-converting enzyme inhibitor (if tolerated). After a 3-week, open-label, up-titration period, 49 of the 56 patients were assigned (in a double-blind fashion using a 2:1 randomization) to receive either carvedilol (25 mg BID, n = 33) or matching placebo (n = 16) for 14 weeks, while background therapy remained constant. Hemodynamic and functional variables were measured at the start and end of the study. Compared with the placebo group, patients in the carvedilol group showed improved cardiac performance, as reflected by an increase in left ventricular ejection fraction (P = .005) and stroke volume index (P = .010) and a decrease in pulmonary wedge pressure, mean right atrial pressure, and systemic vascular resistance (P = .003, .002, and .017, respectively). In addition, compared with placebo, patients treated with carvedilol benefited clinically, as shown by an improvement in symptom scores (P = .002), functional class (P = .013), and submaximal exercise tolerance (P = .006). The combined risk of death, worsening heart failure, and life-threatening ventricular tachyarrhythmia was lower in the carvedilol group than in the placebo group (P = .028), but carvedilol-treated patients had more dizziness and advanced heart block.

CONCLUSIONS

Carvedilol produces clinical and hemodynamic improvement in patients who have severe heart failure despite treatment with angiotensin-converting enzyme inhibitors.

Microinjections of GABAergic agents in the locus coeruleus modify the gain of vestibulospinal reflexes in decerebrate cats

1. Precollicular decerebrate cats show a good postural activity in the four limbs and a small-amplitude vestibulospinal (VS) reflex, as revealed by recording the EMG response of the triceps brachii to sinusoidal roll tilt of the animal at 0.15 Hz, +/- 10 degrees. This preparation was used to study whether inactivation of the locus coeruleus (LC) elicited by local administration either of the GABA-A agonist muscimol or of the GABA-B baclofen produced changes in posture as well as in gain of the VS reflexes. 2. Microinjection into the LC of one side of 0.13-0.25 microliter of a muscimol or baclofen solution (at 2.5 or 1 microgram/microliter saline, respectively) stained with 5% pontamine, usually decreased the extensor tonus in the ipsilateral limbs and to a lesser extent also in the contralateral limbs. However, the amplitude of modulation and thus the gain of the first harmonic component of the multiunit EMG responses of the ipsilateral and to a lesser extent also of the contralateral triceps brachii to the same parameters of labyrinth stimulation increased. The phase angle of the responses remained nearly unchanged by this treatment. The effects appeared 5-10 min after the injection of muscimol, fully developed in 30 min and progressively declined within the following 2-2.5 hours. 3. The increased gain of the VS reflexes acting on the triceps brachii did not depend on the decreased postural activity following the injection of the GABA-A or GABA-B agonist, since it was still observed if the reduced EMG activity following the injection was compensated by an increased static stretch of the muscle. Moreover, the postural and reflex changes described above were not due to irritative events following the injection, since they were not observed in control experiments following injection of 0.25 microliter saline within the LC-complex. On the other hand, postural and reflex changes opposite in sign to those elicited by muscimol or baclofen were obtained by local injection into the LC-complex of a GABA-A or GABA-B antagonist (0.25 microliter of bicuculline or faclofen at 8 micrograms/microliters saline). 4. In some experiments, the decrease in postural activity of the forelimbs after injection of muscimol into the LC complex was followed by transient episodes of postural atonia, which affected not only the ipsilateral but also the contralateral triceps muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Ritanserin, imipramine, and placebo in the treatment of dysthymic disorder

Fifty outpatients with dysthymic disorder (DSM-III) were divided by double-blind randomized assignment into three groups given ritanserin, imipramine, and placebo, respectively. The trial was of 7 weeks' duration; by week 6, imipramine was clearly superior to placebo, whereas by week 7, both drugs caused significantly more improvement than the placebo. Although imipramine had slightly greater efficacy than ritanserin, it also had significantly more side effects. This was particularly evident in the higher dropout rate with imipramine. The efficacy and side effect profile of ritanserin makes it well tolerated and acceptable with dysthymic patients who, although they do not respond as quickly as patients with major depressive disorder, do show significant improvement, given sufficient time.

Modulation of vestibulospinal reflexes through microinjection of an alpha 1-adrenergic antagonist in the dorsal pontine tegmentum of decerebrate cats

1. The possibility that the norepinephrine (NE)-containing locus coeruleus (LC) neurons produce changes in posture as well as in gain of the vestibulospinal (VS) reflexes by acting on the dorsolateral pontine tegmentum (DPT) and the related medullary inhibitory reticulospinal (RS) system through alpha 1-adrenoceptors has been investigated in decerebrate cats. 2. Injection of the alpha 1-adrenergic antagonist prazosin PRZ (0.25 microliter at 0.1-1 microgram/microliter solvent) into the DPT, namely in the dorsal pontine reticular formation (pRF), as well as in the peribrachial nucleus of one side, decreased the postural activity in the ipsilateral limbs while increasing that of the contralateral limbs. In addition, the amplitude of modulation and thus the gain of the multiunit EMG responses of the ipsilateral and to a lesser extent of the contralateral triceps brachii to roll tilt of the animal at 0.15 Hz, +/- 10 degrees, increased. These effects appeared 5-10 min after the injection, reached the highest values in about 40-60 min and persisted for additional 1.5-2 h before disappearing. 3. The effects were site-specific and to some extent dose-dependent. However, neither changes in posture nor in gain of the VS reflexes were obtained after injection in the effective area of an equal volume of solvent. 4. In order to account for these findings it was postulated that the alpha 1-antagonist blocks the tonic inhibitory influence that the NE-containing LC neurons exert on ipsilateral DPT either by exciting through alpha 1-receptors interposed inhibitory interneurons, or by inhibiting presynaptically excitatory afferents to the same pontine tegmental structures. The increased discharge of these neurons and the related medullary inhibitory RS neurons would reduce the postural activity in the ipsilateral limbs. However, since the inhibitory RS neurons show a response pattern to tilt opposite in sign to that elicited by the excitatory VS neurons, we could expect that for a given labyrinth signal, the increased discharge of the RS neurons in the animal at rest would lead to a greater disinhibition of limb extensor motoneurons during ipsilateral tilt. These motoneurons would then respond more efficiently to the same excitatory volleys elicited by given parameters of stimulation, thus leading to an increased gain of the EMG responses of forelimb extensors to labyrinth stimulation. The possibility that the DPT of one side activates inhibitory RS neurons of both sides explains why PRZ increases the gain of the VS reflexes not only ipsilaterally but also contralaterally to the side of the injection.(ABSTRACT TRUNCATED AT 400 WORDS)

Arrest of seizure series induced by an intracortical injection of penicillin in the awake rat

Experiments were performed to answer the question, whether series of generalized tonic-clonic seizures, induced in the awake rat by a local injection of Na-penicillin (PCN) solution into the motor cortex, terminates at the same critical concentration Ct of PCN within the focal area independently of the concentration C0 of PCN injected. Using the PCN diffusion coefficient D = 3.52 x 10(-4) mm2/s and the tortuosity factor lambda = 1.62, the concentration Ct at the onset of the last generalized seizure was calculated. The median duration of seizure series increased from 32 to 190 min, when the dose of injected PCN was raised from 32 to 1000 IU. At the onset of the last seizure, the median concentration Ct within the artificial focus ranged from 2.1 to 4.0 IU/0.5 microliter saline in rats treated with 32 to 125 IU PCN. After induction of convulsive behaviour with C0 = 250, 500, or 1000 IU PCN/0.5 microliter saline, however, Ct was at a higher level between 6.1 and 7.4 IU PCN/0.5 microliter saline. The difference between the cumulated data from the low-dose vs. the high-dose range was significant (p < 0.01). It is concluded that during long-lasting series of generalized seizures, the brain takes advantage of its plastic properties. By forming a counteracting mechanism, it protects itself from extreme epileptiform activity. This autoprotection may be due to the activation of neuronal networks which probably needs a certain frequency of seizures to become operatively.

The benefits of clomipramine-fluoxetine combination in obsessive compulsive disorder

We report the benefits of clomipramine-fluoxetine combination in four cases of severe obsessive compulsive disorder. In two cases, the combination was effective when either drug used singly was ineffective. In the other two cases, fluoxetine adjunct produced benefits with no additional side effects.

[Ring-valve abscess--a diagnostic challenge]

Infective endocarditis is a life-threatening disease which may be complicated by ring-valve abscess. Since this complication increases morbidity and mortality early diagnosis is important. Pericardial effusion complicating infective endocarditis is uncommon and should raise suspicion of the presence of an abscess. We describe 2 patients admitted for infective endocarditis and pericarditis. In both, ring-valve abscess was suspected on clinical grounds. At surgery there was pathological confirmation of the diagnosis. Both patients underwent successful aortic valve replacement with complete recovery. Controlled trials are providing increasing evidence for the superiority of transesophageal echocardiography in detecting valvular vegetations. Moreover, it is the most accurate means of detecting ring-valve abscess in cases of infective endocarditis. In view of these advantages, we propose the use of transesophageal echocardiography in every case of infective endocarditis.