The adult zebrafish as polyhedric model for skeletal studies.

In the last decade, several examples have been produced by scientific literature about zebrafish as a model to study human bone diseases. In fish, bone turnover, reparation and remodeling of the adult bone tissue cannot be studied in embryonic or juvenile stages. In addition, fins and scales represent unique anatomical features useful to study adult bone metabolism and diseases. For these reasons, the adult zebrafish represents an innovative and readily available resource for studying the bone metabolism at cellular and molecular level. Although the adult fish is less used than the embryo, several applications have been found in the last years with the production of innovative pathological models in adult zebrafish, helpful to understand the mechanisms of bone physiopathology. The use of mutants, regenerating organs, transgenic fish and scales have increased the power of this model in the last years.

Effects of bioactive fatty acid amide derivatives in zebrafish scale model of bone metabolism and disease.

The endocannabinoid system (which includes fatty acid derivatives, receptors, and metabolizing enzymes) is involved in a variety of physiological processes, including bone metabolism in which it regulates the function of osteoblasts and osteoclasts, as well as differentiation of their precursors. The zebrafish (Danio rerio) provides a useful animal model for bone research since zebrafish bones develop rapidly and are anatomically similar to mammalian bones. Putative orthologues and paralogs of endocannabinoid genes have recently been identified in zebrafish, demonstrating the presence of cannabinoid type 1 (CB1) and type 2 (CB2) receptors with affinity to endocannabinoid ligands. To identify therapeutic molecules potentially useful in bone-related diseases, we evaluated the in vivo effects of exposure to long-chain fatty acid amides in adult zebrafish. Using a well-established zebrafish scale model, we found that anandamide and N-linoleoylethanolamine are able to stimulate bone formation by increasing alkaline phosphatase activity in physiological conditions. In addition, they prevent the alteration of bone markers in a prednisolone-induced osteoporosis model in adult zebrafish scales, whereas their esterified forms do not. These data suggest that long-chain fatty acid amides are involved in regulating bone metabolism in zebrafish scales and that the CB2 receptor is a key mediator in this process.

Transfer of motor skill learning from the healthy hand to the paretic hand in stroke patients: a randomized controlled trial.

BACKGROUND: Bilateral transfer of a motor skill is a phenomenon based on the observation that the performance of a skill with one hand can "teach" the same skill to the other hand. AIM: In this study the ability of bilateral transfer to facilitate the motor skill of the paretic hand in patients that suffered a stroke was tested. DESIGN: In a randomized controlled trial subjects were randomly assigned to either the test group or the control group. SETTING: The experiment was performed in a general hospital rehabilitation facility for inpatients and outpatients. POPULATION: We studied 20 outpatients, who had their first stroke episode characterized by a brain lesion to a single hemisphere, at the end of their rehabilitation treatment. The criteria used for the selection were based on a physical examination, the time elapsed from the stroke and cognitive requirements. METHODS: The experiment consisted in training the healthy hand of each patient from the test group to execute the nine hole peg test 10 times a day, for three consecutive days, and then test the paretic hand with the same test and with bimanual tasks. The control group was not trained but went through the same analysis. RESULTS: The homogeneity of the two groups has been proven. In the test group we found that the execution speed of the nine hole peg test with the paretic hand, after training the healthy hand, was on average 22.6% faster than the value recorded at baseline. The training had a positive effect on the execution of bimanual tasks. Meanwhile, no significant difference was found in the control group. CONCLUSION: This is the first evidence that bilateral transfer of motor skills is present in patients that suffered a stroke, and that it improves the ability of the affected hand. CLINICAL REHABILITATION IMPACT: This observation could open the way to the development of a new approach for the rehabilitation of stroke patients.

[The role of the selective blocking of angiotensin II receptors in the treatment of cardiovascular diseases]. / Il ruolo del blocco selettivo dei recettori dell'angiotensina II nel trattamento delle patologie cardiovascolari.

Angiotensin II plays an important role in blood pressure control and in water and salt homeosthasis. It is involved in the pathogenesis of hypertension and structural alterations of the vasculature, kidney, and heart, including nephrosclerosis, post infarction remodelling and left ventricular hypertrophy. At least two subtypes of receptors have been identified, angiotensin type 1 (AT1) and type 2 (AT2). The AT1 receptor is responsible for all the known effects of Ang II on blood pressure, osmoregulation, and cell growth and consequently for the contribution to cardiovascular and renal pathology. Research has indicated that the AT1 receptor modulates cardiac and vascular hypertrophy, cellular growth and ventricular remodelling. Evidence suggests that, on the other hand, the AT2 receptor is involved in growth inhibition, inhibits cell proliferation, induces vasodilatation and reverses the AT1 induced hypertrophy. The accumulating evidence appears to demonstrate therefore that the function of these receptor subtypes may exerts opposite effects while stimulated by AngII. The angiotensin receptor antagonists are able to inhibit the renin angiotensin system by blocking selectively the AT1 receptor. It is supposed that AT1 receptor antagonists may provide end organ protection by blocking angiotensin II effects via the AT1 receptor leaving the AT2 receptor unopposed: it is conceivable that the stimulation of AT2 receptors may prevent the hypertropic effects seen in conditions such as LVH, hypertrophy, postinfarction remodeling and repair after injury. For this, the AT1/AT2 selectivity associated to these drugs may be important for their effects and to differentiate them from ACE inhibitors.

[Venous thromboembolism and neoplasms]. / Tromboembolismo venoso e neoplasia.

Venous thromboembolism, including deep vein thrombosis and pulmonary embolism, is a major cause of morbidity and mortality. In most cases, one or more risk factors for removable or persistent venous thromboembolism can be identified. Persistent risk factors include inherited or acquired abnormalities of the hemostatic system and cancer. As Armand Trousseau first suggested, venous thromboembolism may be the first clinical manifestation of an occult cancer. This relationship has recently been confirmed by methodologically well designed studies. Furthermore, venous thromboembolism is the second cause of death in patients with clinically overt cancer. This review summarizes the state of the art of this association. The clinical trials described focus on the need to perform screening for occult cancer in patients with idiopathic venous thromboembolism. How extensive this screening should be is still matter of debate. On the other hand, patients with clinically overt cancer should be considered at high risk for developing venous thromboembolism, and adequate prophylaxis should be used.

Exercise-induced hypoxaemia in emphysematous type chronic obstructive pulmonary disease.

To investigate gas exchange response to exercise, we studied 16 male patients with moderate-to-serve airflow obstruction (forced expiratory volume in one second (FEV1) 39 +/- 10% of predicted value), mild-modest arterial hypoxaemia (arterial oxygen tension (Pa,O2) 9.6 +/- 0.87 kPa) and no arterial hypercapnia (arterial carbon dioxide tension (Pa,CO2) 5.04 +/- 0.45 kPa), referred to as emphysematous-type chronic obstructive pulmonary disease (COPD) clinical pattern. During maximal exercise tests, Pa,O2 increased by more than 0.3 kPa in eight patients (Group A) and fell by more than 0.3 kPa in the other eight patients (Group B). Pulmonary function tests, maximal inspiratory pressure at the mouth, values at maximum cycle incremental exercise and baseline arterial blood gases did not differ significantly between the two groups. We, therefore, showed that common pulmonary function measurements at rest and during exercise were not useful in identifying patients who underwent exercise-induced hypoxaemia. Furthermore, we suggest that patients with the same clinical pattern of chronic obstructive pulmonary disease and the same degree of airflow obstruction and gas exchange impairment could develop a different adaptation to a maximal exercise test, and that the presence of exercise-induced hypoxaemia might be related to pathological features of emphysema more than to different respiratory functional measurements.

First bleeding episode from oesophageal varices in cirrhotic patients: a prospective study of endoscopic predictive factors.

Two hundred patients affected by liver cirrhosis and oesophageal varices were studied in 9 Gastrointestinal Units in Lombardy (Northern Italy) in order to assess factors possibly related to variceal bleeding. Only patients without any previous episode of gastrointestinal bleeding were included in the prospective evaluation. For each patient demographic data, aetiology of cirrhosis, various clinical and biochemical parameters able to group patients into the three Child-Pugh Classes, endoscopic items for calculation of Beppu's and of NIEC prognostic scores were recorded on computerized cards. Patients were regularly interviewed every three months for one year and underwent an upper gastrointestinal endoscopy at enrollment, after six months and in case of bleeding. Within the twelve-month follow-up period, 29 out of the 200 patients (14%) bled and 52 out of 200 died (26%). In 16 of the 52 patients who died (59% of bleeding patients) death was directly related to gastrointestinal bleeding. Bleeding from oesophageal varices was endoscopically proven in 19/29 patients, in another 9 bleeding was classified as from unknown source and in one patient a bleeding gastric ulcer was diagnosed. Univariate analysis of all the recorded clinical, biochemical and endoscopic parameters, performed by Chi-square method and Fisher exact test showed that the presence of RWM (p < 0.001) was the only factor significantly associated to variceal bleeding within one year. Relationship between size of varices and bleeding was very close to the statistical significance but did not achieve it (p = 0.058).

Randomised comparison of subcutaneous heparin, intravenous heparin, and aspirin in unstable angina. Studio Epoorine Sottocutanea nell'Angina Instobile (SESAIR) Refrattorie Group.

Intravenous heparin has been used in the control of myocardial ischaemia in patients with unstable angina. We set out to assess the efficacy of subcutaneous heparin in reducing myocardial ischaemia in patients with unstable angina. 343 of 399 patients with unstable angina were monitored for 24 h and 108 were refractory to conventional antianginal treatment and were entered into a randomised multicentre trial. 37 patients were assigned to heparin infusion (partial thromboplastin time 1.5-2 times baseline), 35 to subcutaneous heparin (adjusted dose with partial thromboplastin time 1.5-2 times baseline), and 36 to aspirin (325 mg daily). All had additional conventional antianginal therapy. After the run-in patients were monitored for 3 days. The primary endpoint was reduced myocardial ischaemia assessed by the number of anginal attacks, silent ischaemic episodes, and duration of ischaemia per day. At 1 week and 1 month we accounted for anginal attacks and other clinical events (myocardial infarction, revascularisation procedures, and death). Aspirin did not significantly affect the incidence of myocardial ischaemia. On the first 3 days, infused and subcutaneous heparin significantly decreased the frequency of angina (on average by 91% and 86%, respectively), episodes of silent ischaemia (by 56% and 46%), and the overall duration of ischaemia (66% and 61%) versus run-in day and aspirin (p < 0.001 for all variables). The favourable effects of heparin therapy remained evident during follow-up. Only minor bleeding complications occurred. Subcutaneous heparin is effective in the control of myocardial ischaemia in patients with unstable angina.

The renal excretory activity of atrial natriuretic factor is independent of renal prostaglandins in humans.

Since renal prostaglandins may contribute to natriuresis induced by endogenous atrial natriuretic factor (ANF), acute volume expansion (AVL), a known stimulus of ANF and prostaglandins, was induced in 8 healthy women in order to test whether the consequent sodium and water diuresis is altered by prostaglandin inhibition. AVL (i.v. infusion of a 2 liter 5% glucose solution in 1 h) was infused after placebo and after inhibition of prostaglandins with diclofenac (200 mg/day orally for 4 days), in a double blind randomized cross-over fashion. Urinary eicosanoids (PGE2, PGF2 alpha, 6-ketoPGF1 alpha, TXB2--RIA), plasma ANF (RIA) and urinary electrolytes were determined before, during and after AVL under both placebo and diclofenac regimes. During placebo, AVL induced sustained increases in plasma ANF (174% at peak, p less than 0.001 ANOVA), excretion of the four eicosanoids (149%-1172%, p less than 0.005-0.001), urinary volume (UV, 815%, p less than 0.001), natriuresis (UNa, 98%, p less than 0.005) and in kaliuresis (UK, 90%, p less than 0.001). Cyclooxygenase inhibition resulted in a reduction of over 70% in both baseline values and AVL-induced increase of eicosanoids. It did not alter either baseline levels or AVL-stimulated ANF, UV, UNa and UK in relation to placebo. The present results suggest that the diuretic and natriuretic activity of ANF is not mediated by renal PGs in humans.

Repeated sympathetic stimuli elicit the decline and disappearance of prostaglandin modulation and an increase of vascular resistance in humans.

To investigate the role of prostaglandins I2 and E2 in modulating the vasoconstrictor response to sympathetic stimulation, repeated and proximate cold pressor tests were performed in 23 healthy young volunteers. Limb vascular resistance (blood flow measured by venous occlusion plethysmography), prostaglandin I2 (as 6-ketoprostaglandin F1 alpha) and prostaglandin E2 plasma levels (detected by radioimmunoassay), and plasma catecholamines (detected by high-performance liquid chromatography and electrochemical detection) were measured. A progressive increase in the duration of the vasoconstrictor response was observed with repetition of cold applications (p less than 0.001, by analysis of variance for trends). This increase was associated with a progressive decrease in cold-induced elevation of 6-ketoprostaglandin F1 alpha and prostaglandin E2 plasma levels until, after five stimulations, neither prostaglandin was detectable. The maximum detected concentration of norepinephrine did not significantly change, but its area under the curve in time showed a trend toward an increase. Epinephrine levels did not significantly change. The increase of vascular resistance was significantly correlated with the decrease of both prostaglandins (r = 0.93, p less than 0.05 for prostaglandin E2 and r = 0.89, p less than 0.05 for 6-ketoprostaglandin F1 alpha), whereas no significant correlations were found between variations of vascular resistance and catecholamines. Prostaglandin blockade induced by diclofenac sodium administration caused, from the first cold application, a pattern of the vasoconstrictor response and plasma prostaglandin and norepinephrine changes similar to that observed at the fifth cold application in untreated subjects, when prostaglandins are no longer detectable in plasma. We conclude that an increased vasoconstrictor response to sympathetic stimulation in humans may result from a diminished inhibitory influence of prostaglandins on adrenergic transmission.

Defective coronary prostaglandin modulation in anginal patients.

In order to investigate whether coronary vasodilating prostaglandins (PGI2 and PGE2) have a role in the pathophysiology of myocardial ischemia, 26 patients with angina pectoris and 23 control subjects (nonischemic patients) were studied by assessing coronary hemodynamics and prostaglandin formation in relation to sympathetic stimulation. Following a cold pressor test (CPT), coronary prostaglandin output markedly increased (p less than 0.001) and coronary vascular resistance (CVR) decreased (p less than 0.001) in all control subjects. In contrast, in anginal patients prostaglandins in the coronary sinus were undetectable and after CPT prostaglandin output did not increase, whereas CVR paradoxically increased (p less than 0.001). In control subjects the inhibition of coronary prostaglandin formation (by ketoprofen [1 mg/kg intravenously] or by aspirin [15 mg/kg intravenously]) caused a paradoxical increase of CVR following CPT (p less than 0.001). In anginal patients the inhibition of prostaglandins further exaggerated the increase of CVR after CPT (p less than 0.001). These results indicate that coronary vasodilating prostaglandin PGI2 and PGE2 play a role in modulating coronary vascular response to sympathetic stimulation induced by CPT. Their defective production in anginal patients may be responsible for the paradoxical increase in CVR following sympathetic stimulation.

Prophylaxis of fatal pulmonary embolism in general surgery using low-molecular weight heparin Cy 216: a multicentre, double-blind, randomized, controlled, clinical trial versus placebo (STEP). STEP-Study Group.

The effectiveness of low-molecular weight heparin CY 216 in the prophylaxis of fatal pulmonary embolism in patients undergoing general surgery was assessed in a multicentre, double-blind, randomized, clinical trial against placebo. A total of 4,498 patients aged over 40 undergoing general surgery were enrolled in the 18 centres which took part in the trial. Patients received a single daily subcutaneous injection of 7,500 anti-Xa units I.C. of CY 216 or placebo two hours before surgery, 12 hours after the initial injection and then daily for at least seven days. A post-mortem examination had to be carried out in every patient who died. The two groups of patients were well-matched for age, sex, type of disease, site and duration of operation as well as for incidence of risk factors which could predispose to the development of thromboembolism. Twenty-six deaths were recorded and validated: eight (0.36%) in the CY 216 group and 18 (0.80%) in the placebo group (p less than 0.05). At the post-mortem examination, carried out in 23 patients (88.5%), two deaths were found to be directly due to pulmonary embolism (0.09%) in the CY 216 group and four (0.18%) in the placebo group. Pulmonary embolism contributed to death in four other placebo-treated patients. Pulmonary or extrapulmonary thromboembolism was a significantly less frequent direct cause of death (p less than 0.05) in the CY 216 group (two pulmonary embolisms) than in the placebo group (four pulmonary embolisms, one acute myocardial infarction, one disseminated intravascular coagulation, two ischemic cerebral strokes).(ABSTRACT TRUNCATED AT 250 WORDS)

The antihypertensive and renal activities of potassium canrenoate are associated with increased renal prostaglandin excretion.

1. In a double-blind, randomized, cross-over study the effects of potassium canrenoate administration (100 mg twice daily for 10 days orally) on renal prostaglandin synthesis (prostaglandin E2 and prostaglandin F2 alpha) were evaluated in 10 normotensive females and in 10 females with essential hypertension. 2. When compared with normotensive subjects, hypertensive patients in baseline conditions showed a reduced excretion of urinary prostaglandin E2 associated with an excessive prostaglandin F2 alpha production. 3. Potassium canrenoate significantly reduced mean blood pressure in hypertensive patients [from 118.9 +/- 8.7 mmHg (1.62 +/- 0.12 kPa) to a peak minimum value of 104.7 +/- 9.8 mmHg (1.42 +/- 0.13 kPa) on the seventh day of treatment; P less than 0.01 for the whole period] but not in control subjects [from 88 +/- 9.4 mmHg (1.20 +/- 0.13 kPa) to 84.3 +/- 8.3 mmHg (1.15 +/- 0.11 kPa) on the eighth day, NS] even though potassium canrenoate significantly increased sodium excretion in both groups. Renal prostaglandin excretion was affected differently in the two groups: in control subjects excretion of both prostaglandin E2 and prostaglandin F2 alpha was increased after drug administration, whereas in hypertensive patients only prostaglandin E2 excretion was enhanced.

Efficacy of mexiletine in chronic ventricular arrhythmias: a multicentre double-blind medium-term trial.

In a multicentre double-blind, inpatient, placebo-controlled trial the effects on premature ventricular beats (PVBs) of mexiletine in a standard, submaximal dose were studied by Holter monitoring in 144 outpatients. After wash-out, mexiletine was administered for 14 days. The effects were re-tested, after one week of a placebo, in a second 14-day period of mexiletine administration. Of the patients 73% in the first period and 82.5% in the second period responded to mexiletine (a reduction of 75% or more of PVBs/24 h--p less than 0.001 compared with the placebo for both periods). Mexiletine also significantly reduced the Lown class of PVBs and the frequence of paired PBVs, ventricular tachycardia, multiform beats and R on T wave phenomenon. Mexiletine showed an equivalent effectiveness in the four main aetiological groups of arrhythmias. Fifty nine patients complained of adverse effects (gastrointestinal or neurological) the intensity of which led to the stopping of the treatment in 16 of them. These results show that mexiletine is highly effective, even in submaximal doses, in preventing ventricular arrhythmias of whatever origin.

Pharmacokinetics and tolerance of a new penem antibiotic, FCE 22101, in healthy volunteers after a single intravenous dose.

The clinical tolerance and pharmacokinetics of FCE 22101 (sodium (5R, 6S)-6-[(1R)-hydroxyethyl]-2-carbamoyloxymethyl-2-penem-3-carboxylate), a new penem antibiotic, have been studied after giving a single i.v. dose of 4 mg.kg-1 to ten healthy male volunteers. The pharmacokinetics was estimated according to a two-compartment open model. The peak plasma concentration (Cmax) was 15.5 (1.08) micrograms.ml-1, mean (SEM). FCE 22101 was rapidly cleared from the systemic circulation [t 1/2 lambda z = 44.2 (4.2) min; CL = 7.21 (0.47) ml.kg-1.min-1]. The mean apparent volume of distribution at steady-state was 246 (16.9) ml.kg-1. The mean residence time relative to the 10 min infusion was 39.4 (1.5) min. Urinary recovery of FCE 22101 showed wide inter-subject variation, ranging from 10.2 to 53.6% of the dose. No subject complained of adverse effects.

Decrease in frequency of anginal episodes by control of thrombin generation with low-dose heparin: a controlled cross-over randomized study.

Increased thrombin generation is frequently associated with an increase in anginal activity. A cross-over, single-blind, completely randomized study was planned in order to evaluate whether the control of thrombin generation affected the increase in anginal activity. After discharge from the hospital, 24 patients (18 men and 6 women, aged 40 to 69 years) suffering from spontaneous angina were followed up to 12 months and were alternatively treated during two consecutive 6-month periods with calcium heparin, 12,500 IU by the subcutaneous route, or with placebo by the intramuscular route, in addition to the usual antianginal medications. Thrombin generation and clinical activity of angina were assessed every 15 days by measuring fibrinopeptide A (FPA) plasma levels and by grading in three classes (symptomless, mildly symptomatic, and severely symptomatic) the anginal activity on the basis of the number and the time concentration of the ischemic attacks and ECG changes. Low-dose heparin treatment significantly reduced both the FPA plasma level (from 4.1 +/- 3.7 to 2.3 +/- 1.8 ng/ml, p less than 0.001) and the clinical activity of angina. During heparin treatment, the frequency of the observations in the severely and mildly symptomatic classes decreased, respectively, by 53% and by 30%, whereas that in the symptomless class increased by 23% (p less than 0.001) in comparison with the period on placebo. Present results indicate that the control of thrombin generation obtained by low-dose heparin treatment favorably affects the degree of anginal activity in patients with spontaneous angina.

Intravenous dilazep reduces blood pressure and peripheral vascular resistance in humans.

Dilazep, a coronary vasodilating drug with adenosine-mediated activity, was tested (acute double-blind study versus placebo) for its antihypertensive activity in 12 patients who had mild to moderate hypertension. Dilazep (0.2 mg/kg body weight by IV infusion for ten minutes) significantly reduced systolic and diastolic blood pressure (random-zero sphygmomanometer) on average by 13.3 and 10.6 mm Hg respectively. The antihypertensive effect started rapidly, reached its maximum 20 minutes after administration, and lasted for 90 minutes. Heart rate significantly increased between 10 and 30 minutes. The antihypertensive effect of dilazep was associated with a relevant vasodilating effect as demonstrated by the changes in upper limb blood flow (strain-gauge plethysmography, +32%; P less than .001) and vascular resistance (-29%, P less than .001). The maximal reduction of vascular resistance was directly correlated to its baseline value. For these characteristics of action, at least in acute administration, dilazep would be useful agent for the treatment of high blood pressure in mild to moderately hypertensive patients.