Dynamic membrane patterning, signal localization and polarity in living cells.

We review the molecular and physical aspects of the dynamic localization of signaling molecules on the plasma membranes of living cells. At the nanoscale, clusters of receptors and signaling proteins play an essential role in the processing of extracellular signals. At the microscale, "soft" and highly dynamic signaling domains control the interaction of individual cells with their environment. At the multicellular scale, individual polarity patterns control the forces that shape multicellular aggregates and tissues.

Laser removal of tattoos.

In Western countries the phenomenon of "tattooing" is expanding and tattoos are considered a new fashion among young people. In this paper we briefly trace the history of tattooing, the techniques used, the analysis of pigments used, and their possible adverse reactions. We also carried out a review of the international literature on the use of Q-switched laser in tattoo removal and its complications, and we describe our experience in the use of this technique.

Ehlers-Danlos syndrome: case report and an electron microscopy study.

Ehlers-Danlos syndrome (EDS) type III is a inherited connective tissue disorders characterized by extensibility of the skin, hypermobility of the joints, chronic pain, tissue fragility, easy bruising, and delayed wound healing with result of atrophic scars. The patients report commonly a history of recurrent dislocations of the shoulders and knees after low-impact trauma, chronic joint pain, and early osteoarthritis, which lead to diagnosis. The pathogenesis of this condition is unknown, and the diagnosis is generally made in adult age, based only on clinical criteria. In this report, we describe a case of a 50-year-old woman with a 30-year history of recurrent dislocations and atrophic scars. We performed diagnosis of EDS type III after a complete clinical and instrumental evaluation, comprising of histological and electron microscopic studies, that highlighted collagen abnormalities.

Epilepsy and argininosuccinic aciduria.

BACKGROUND: We have reviewed the occurrence of epilepsy in our patients with argininosuccinic aciduria (ASA) (OMIM 207900) and the possible relationship of late epilepsy to symptomatic seizures in the neonatal period, hyperammonaemia and treatments. METHODS: We retrospectively analysed 11 ASA patients (8 neonatal onset and 3 late onset), 6 of whom had developed epilepsy. RESULTS: Epilepsy in our sample was frequent (55 %). It developed after a seizure-free period from the onset of the metabolic disease and seizures were responsive to treatment in all cases. Arginine plasma levels were kept in the same range for the 2 groups of patients with and without epilepsy. CONCLUSIONS: Although epilepsy is reported to be common among patients with ASA, very few long-term follow-up studies are available. The pathophysiological mechanism of epileptogenesis remains unclear. Neither hyperammonaemia nor acute symptomatic seizures at birth seem to be predictive of late epilepsy. Excessive arginine dosages as a cause of epilepsy could be reasonably excluded since our 3 late onset patients developed epilepsy before the diagnosis of ASA, at a time when they were likely to be arginine deficient. Arginine deficiency may not be excluded as cause of epilepsy, but further studies are needed to define its role.

Mitral valve prolapse and abnormalities of haemostasis in children and adolescents with migraine with aura and other idiopathic headaches: a pilot study.

OBJECTIVE: To investigate the prevalence of mitral valve prolapse (MVP) and abnormalities of haemostasis in children and adolescents with migraine with aura (MA) compared with peers affected by other idiopathic headaches. MATERIALS AND METHODS: We recruited 20 MA patients (10 men and 10 women; age range 8-17 years) and 20 sex- and age-matched subjects with other idiopathic headaches. Both groups underwent colour Doppler transthoracic echocardiography to detect MVP and the following laboratory work-up: plasma prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen, protein C, protein S, homocysteine, lupus anticoagulant, von Willebrand factor (vWF) ristocetin cofactor activity, immunoglobulins (Ig) G and M anticardiolipin antibodies (aCL). Factor V Leiden, factor II and methylenetetrahydrofolate reductase were investigated (we did not test the entire genes, but screened for specific point mutations). RESULTS: The prevalence of MVP was significantly higher in the MA subjects than in the patients affected by other idiopathic headaches (40% vs 10%; P < 0.05). Moreover, the MA patients showed a higher rate of above-normal IgM aCL titres (45% vs 10%; P < 0.05). Finally, in the group of patients with MVP we found a higher prevalence of aCL in those with MA compared with those affected by other idiopathic headaches. CONCLUSIONS: A proportion, at least, of the MA patients showed a more complex phenotype characterized by MVP and/or positive aCL titres. The pathogenetic role of these associations is obscure and larger studies are needed to confirm the usefulness of echocardiographic and laboratory investigations in this area and to identify possible new treatment approaches that might be explored in this group of MA patients.

Evaluation of non-commercial models for genotoxicity and carcinogenicity in the assessment of EFSA's databases.

Over the past years, the European Food Safety Authority (EFSA) released to the public domain several databases, with the main objectives of collecting and storing hazard data on the substances considered in EFSA's risk assessment and secondly to serve as a basis for further development of in silico tools such as quantitative structure-activity relationship (QSAR) models. In this work, we evaluated the ability of freely available QSAR models to estimate genotoxicity and carcinogenicity properties and their possible use for screening purposes on three different EFSA's databases. With an accuracy close to 90%, the results showed good capabilities of QSAR models to predict genotoxicity in terms of bacterial reverse mutation test, while statistics for in vivo micronucleus test are not satisfactory (accuracy in the predictions close to 50%). Interestingly, results on the carcinogenicity assessment showed an accuracy in prediction close to 70% for the best models. In addition, an example of the potential application of in silico models is presented in order to provide a preliminary screening of genotoxicity properties of botanicals intended for use as food supplements.

Could deep learning in neural networks improve the QSAR models?

Assessing chemical toxicity is a multidisciplinary process, traditionally involving in vivo, in vitro and in silico tests. Currently, toxicological goal is to reduce new tests on chemicals, exploiting all information yet available. Recent advancements in machine learning and deep neural networks allow computers to automatically mine patterns and learn from data. This technology, applied to (Q)SAR model development, leads to discover by learning the structural-chemical-biological relationships and the emergent properties. Starting from Toxception, a deep neural network predicting activity from the chemical graph image, we designed SmilesNet, a recurrent neural network taking SMILES as the only input. We then integrated the two networks into C-Tox network to make the final classification. Results of our networks, trained on a ~20K molecule dataset with Ames test experimental values, match or even outperform the current state of the art. We also extract knowledge from the networks and compare it with the available mutagenic structural alerts. The advantage over traditional QSAR modelling is that our models automatically extract the features without using descriptors. Nevertheless, the model is successful if large numbers of examples are provided and computation is more complex than in classical methods.

Outcome of patients listed for heart transplantation after a failed surgical ventricular restoration procedure.

Patients with end-stage ischemic cardiomyopathy (IHD) and left ventricular (LV) dilatation are increasingly treated by means of surgical ventricular restoration (SVR). In some patients, SVR can delay heart transplantation (HTX). We retrospectively analyzed our experience, trying to ascertain whether HTX after a failed SVR (fSVR) carried a greater mortality risk. Since 1985, we performed 742 HTX. Since June 1999, 133 IHD patients were listed for HTX. We assigned them to 3 groups: (A) not a redo (n=54); (B) redo after coronary artery bypass grafting (n=54); and (C) redo after fSVR (n=25). Respectively, 37, 33, and 12 patients underwent HTX with in-hospital mortality after HTX of 4/37 (10.8%), 12/33 (36.4%), and 2/12 (16.7%). Mortality on the list was 9/54 (16.7%), 11/54 (20.4%), and 7/25 (28.0%) respectively. Removal from the list occurred in 4, 5, and 2 patients, and 4, 5, and 4 patients are still awaiting HTX, respectively. In group C, the mean time from SVR to HTX list was 45.6+/-43.3 months, and list mortality occurred after 5.83+/-5.81 months. In-hospital mortality in both patients of group C was due to the occurrence of multisystem organ failure; 10/12 were extubated after 19.3+/-9.6 hours and discharged from the intensive care unit after 3.9+/-1.6 days. The recorded complications were: 3 acute renal failure, 1 pericardial effusion, and 2 episodes of acute rejection. Since only 5/25 patients with fSVR had undergone SVR at our institution, we cannot establish which patients were really eligible for HTX at the time of SVR. Our experience showed that patients listed for HTX displayed a high list mortality, but that HTX after a failed SVR did not seem to have a poorer outcome than HTX after previous conventional CABG.

Possible role of everolimus in improving renal function in long-term heart transplantation.

Patient survival after heart transplantation has improved dramatically since the availability of calcineurine inhibitor (CNIs); the number of long-term patients is progressively increasing. However, in these patients, nephrotoxicity of CNIs has been largely responsible for the progressive development of renal dysfunction. Since impaired renal function is an important issue that reduces long-term patient survival, it is important to develop strategies to improve renal function while maintaining immunologic safety to preserve graft function. Everolimus is an mTOR inhibitor sirolimus analogue, that has proved, to be highly efficacious to prevent acute myocardial rejection and reduce the severity of cardiac allograft vasculopathy in de novo HTx patients. There is reasonable evidence that, in long term heart transplanted patients, renal function may improve when everolimus is administered associated with a progressive reduction of CNIs. So far there is no evidence to identify which patient may benefit from this therapeutic approach. Indeed everolimus alone may be equally effective to prevent rejection and improve renal function when CNIs are completely discontinued, but data are still lacking on the risks, dosages and side effects of this type of immunosuppression. Ongoing clinical studies will provide further guidance about the possibility to halt or reduce the progression of renal impairment in long term heart transplant patients.

Atrial natriuretic peptide in diabetic and nondiabetic patients with and without heart transplantation.

BACKGROUND: Natriuretic peptides are useful markers for risk stratification of patients with heart disease. However, conflicting results have been reported about circulating atrial natriuretic peptide (ANP) concentration in heart transplant recipients. METHODS: To ascertain the effects of diabetes and acute insulin administration on plasma ANP concentrations in a model of heart denervation, we studied 12 diabetic (D-OHT) and 6 nondiabetic heart-transplanted (OHT) patients using the euglycemic-hyperinsulinemic clamp and oral glucose tolerance tests. Five patients with type 2 diabetes without heart transplantation (D) and 9 healthy subjects (NOR) matched for anthropometric features served as the controls. RESULTS: Means baseline plasma ANP concentration was higher in D-OHT (82 +/- 15 pg/mL) than in OHT or NOR (27 +/- 4 or 30 +/- 5; P < .01), but was not different than D (69 +/- 12; P = .82). During the clamp plasma ANP showed similar increases in all groups (49 +/- 4, 39 +/- 3, 59 +/- 4, and 49 +/- 3% in D-OHT, OHT, D, and NOR; P < .02 vs basal, P = NS among groups). Plasma osmolarity and catecholamines were also not different among groups and did not increase during the clamp. Fasting plasma ANP concentrations correlated with plasma glucose concentrations measured 120 minutes after oral glucose tolerance testing. CONCLUSIONS: Among heart transplantation recipients fasting plasma ANP concentrations were not different at 5 to 6 years after the surgical procedure than in nondiabetic controls. Increased ANP concentrations were observed among recipients with diabetes and among nontransplanted diabetic patients. Although the insulin-induced increment in ANP concentrations was not different among groups, circulating ANP was strongly associated with glucose tolerance status.

Role of repulsive factors in vascularization dynamics.

Capillary networks are essential in vertebrates to supply tissues with nutrients. Experiments of in vitro capillary formation show that endothelial cells randomly spread on a gel matrix autonomously organize to form vascular networks with a characteristic length independent of the initial cell density. A mathematical model based on free cell migration and on cell cross-talk mediated by soluble chemical factors has been recently proposed and explains the main dynamical and geometrical properties of the networks. We extend this model introducing the action of repulsive factors and we show that their activity results in a larger degree of reorganization of cellular matter and in more robust control over the size of the growing vascular network.

The binding of bilirubin to albumin. A study using spin-labelled bilirubin.

Binding between human serum albumin and a spin-labelled derivative of bilirubin was investigated by circular dichroism, fluorescence quenching, electron spin resonance and visible spectroscopy. The orders of magnitude of the binding constants obtained by flurorescence quenching and electron spin resonance spectroscopies were 10(7) and 10(3) 1 . mol-1, respectively. These data suggest that most spin-labelled bilirubin interacts with human serum albumin at the side not holding the spin-labelled side-arm. CD measurements showed the presence of at least two sites, associated with opposite Cotton effects. It is worthy of note that the Cotton sign of the first site is inverted with respect to the corresponding one of bilirubin. CD measurements on mixed systems (spin-labelled bilirubin/human serum albumin/bilirubin) were also performed. The decomposition of the ternary curves shows that the rotatory power of bilirubin bound to human serum albumin is higher in the ternary system than in the binary (bilirubin/human serum albumin). The corresponding CD measurements for the binding between spin-labelled bilirubin and bovine serum albumin are also reported and discussed.

Synthesis and pharmacological characterization of enantiomerically pure muscarinic agonists: difluoromuscarines.

The four homochiral 4-deoxy-4,4-difluoromuscarine stereoisomers (difluoromuscarines) were prepared in very high enantiomeric excess. A convenient sequence based on the use of natural as well as "unnatural" ethyl lactate allowed the synthesis of target compounds, whose absolute configuration is dictated by that of the starting synthon. Quaternary ammonium salts (+)-5, (-)-5, (-)-6, and (+)-6 were tested in vitro on guinea pig tissues, and their muscarinic potency was evaluated at M2 (heart) and M3 (ileum and bladder) muscarinic receptor subtypes. The eutomer (+)-5 and distomer (-)-5 were also tested in vivo on pithed rat, and their muscarinic activity at the M1 receptor subtype was compared with those of racemic muscarine [(+/-)-1] and (2S,4R,5S)-4-deoxy-4-fluoromuscarine [(+)-4]. Further pharmacological parameters such as affinity, relative efficacy, and enantioselectivity have been determined for compounds (+)-5 and (-)-5 at M2 (heart force and rate) and M3 (ileum and bladder) receptors in order to investigate muscarinic receptor heterogeneity. The four homochiral difluoromuscarines behave as muscarinic agonists in all the tests with a potency trend which is different from that previously observed with the 4-deoxy-4-fluoromuscarines and (+/-)-1, thus indicating the intervention of the second fluorine atom on the receptor-ligand interaction. Moreover, the second fluorine atom produces significant differences in the affinity and relative efficacy values of compounds (+)-5 and (-)-5 at M2 and M3 subtypes, which could be attributed to a heterogeneity between the muscarinic receptors mediating heart rate and heart force and those involved in the contraction of ileum and bladder.

Epstein-Barr virus-negative lymphoproliferate disorders in long-term survivors after heart, kidney, and liver transplant.

BACKGROUND: Solid organ transplant patients undergoing long-term immunosuppression have high risk of developing lymphomas. The pathogenesis of the late-occurring posttransplantation lymphoproliferative disorders (PTLD) have not yet been extensively investigated. METHODS: We studied 15 patients who developed PTLD after a median of 79 months (range 22-156 months) after organ transplant. Clonality, presence of Epstein-Barr virus (EBV) genome, and genetic lesions were evaluated by Southern blot analysis or polymerase chain reaction. RESULTS: All monomorphic PTLD and two of three polymorphic PTLD showed a monoclonal pattern. Overall, 44% of samples demonstrated the presence of the EBV genome. Within monomorphic PTLD, the EBV-positive lymphomas were even lower (31%). A c-myc gene rearrangement was found in two cases (13%), whereas none of the 15 samples so far investigated showed bcl-1, bcl-2, or bcl-6 rearrangement. The modulation of immunosuppression was ineffective in all patients with monomorphic PTLD independent of the presence of the EBV genome. The clinical outcome after chemotherapy was poor because of infectious complications and resistant disease. With a median follow-up of 4 months, the median survival time of these patients was 7 months. CONCLUSIONS: Late occurring lymphomas could be considered an entity distinct from PTLD, occurring within 1 year of transplant, because they show a histological and clinical presentation similar to lymphomas of immunocompetent subjects, are frequently negative for the EBV genome, are invariably clonal, and may rearrange the c-myc oncogene. New therapeutic strategies are required to reduce the mortality rate, and new modalities of long-lasting immunosuppression are called for.

Troponin I as a specific marker for heart damage after heart transplantation in a patient with becker type muscular dystrophy.

In a patient with Becker type muscular dystrophy, the development of cardiomyopathy may require heart transplantation, and during both the perioperative period and later it is useful to determine whether myocardial cell damage is occurring; however, the measurement of serum levels of creatine kinase (CK), MB isoenzyme, is not useful because that isoenzyme is released by the dystrophic skeletal muscle, as well as damaged myocardium. Because cardiac troponin I (cTn I) seems to be quite specific for myocardial cells, we reasoned that measurement of serum levels of this protein could distinguish between myocardial damage and skeletal muscle disease in this patient during and after transplantation. During the immediate postoperative period, the time course of the release of total CK (tCK), CK MB mass, myoglobin, and cTn I were different, yielding a peak within 4 hours for CK MB, 24 hours for myoglobin and 36 hours for tCK and cTn I. During the first postoperative year, the patient displayed a release of tCK, CK MB, and myoglobin; cTn I was constantly lower than the reference value for cardiac myocyte necrosis, suggesting the presence of a continuous muscular damage without any myocardial involvement and an accurate specificity of cTn I to differentiate between myocardial and muscular cell damage in patients with neuromuscular disorders.

Pediatric heart transplantation without chronic maintenance steroids.

From 1986 to February 1993, 40 children aged 2 months to 18 years (average age 10.4 +/- 5.8 years) underwent heart transplantation. Indications for transplantation were idiopathic cardiomyopathy (52%), congenital heart disease (35%) with and without prior repair (71% and 29%, respectively), hypertrophic cardiomyopathy (5%), valvular heart disease (3%), and doxorubicin cardiomyopathy (5%). Patients were managed with cyclosporine and azathioprine. No prophylaxis with antilymphocyte globulin was used. Steroids were given to 39% of patients for refractory rejection, but weaning was always attempted and generally successful (64%). Five patients (14%) received maintenance steroids. Four patients died in the perioperative period and one died 4 months later. There have been no deaths related to rejection or infection. Average follow-up was 36 +/- 19 months (range 1 to 65 months). Cumulative survival is 88% at 5 years. In patients less than 7 years of age, rejection was monitored noninvasively. In the first postoperative month, 89% of patients were treated for rejection. Freedom from serious infections was 83% at 1 month and 65% at 1 year. Cytomegalovirus infections were treated successfully with ganciclovir in 11 patients. No impairment of growth was observed in children who underwent transplantation compared with a control population. Twenty-one patients (60%) have undergone annual catheterizations and no sign of graft atherosclerosis has been observed. Seizures occurred in five patients (14%) and hypertension was treated in 10 patients (28%). No patient was disabled and no lymphoproliferative disorder was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of postoperative pain: comparison between administration at fixed hours and 'on demand' with intramuscular analgesics.

From the data in the literature it can be seen that 40% of the surgical population has insufficient postoperative analgesia. Many reasons have been given for this: pain control delegated to the doctor on duty and/or the nursing staff; administration of drugs 'on demand', if the patient asks for them, or the nurses feel it to be necessary; fear of causing side effects such as respiratory insufficiency; or provoking addiction by giving narcotics. The aim of this paper is to evaluate the intensity of pain, the side effects, the degree of activity, anxiety, feeling of weakness and the mood of patients surgically treated for oncological diseases of the thorax and upper abdomen, comparing two different antalgic approaches. Thirty-five patients were studied. Pain was treated on demand with a narcotic, or an anti-inflammatory drug, or not treated at all; 20 patients were treated with analgesics given at predetermined hours, following the regime: methadone 10 mg intramuscularly (i.m.) every 12 h from the first to the third day following surgery and sodium diclofenac 75 mg (i.m.) every 12 h from the fourth to the seventh day. Results showed that patients treated with analgesics given intramuscularly at fixed hours have a significantly better pain control during the whole week of treatment (P less than 0.001), on average sleep more (P less than 0.001), spend more time standing or sitting and fewer hours lying down (P less than 0.001), have a higher performance status and feel less weak (P less than 0.05) than the group of patients treated with drugs 'on demand', or not treated at all.

Mitral valve repair and transesophageal echocardiographic findings in a high-risk subgroup of patients with active, acute infective endocarditis.

BACKGROUND AND AIM OF THE STUDY: Limited data are available regarding the efficacy of mitral valve repair in patients affected by active, acute infective endocarditis. In addition, the predictivity of transesophageal echocardiography (TEE) for guiding the surgical decision-making process in these patients has not yet been reported. The study aim was to evaluate the long-term results of mitral valve repair and role of TEE in active, acute infective endocarditis. METHODS: The study population consisted of patients affected by infective endocarditis of the mitral valve who underwent surgery. TEE was performed intraoperatively to guide the best surgical approach. All patients were followed up (mean 73+/-8 months) after surgery. RESULTS: Twenty-eight patients underwent surgery for infective endocarditis; of these, 13 had mitral valve repair for active, acute infective endocarditis and formed the basis of the study. Sensitivity, specificity, positive predictive value, negative predictive value of TEE in detecting the mechanism of mitral regurgitation were 87%, 100%, 100% and 92%, respectively. The predictivity test of TEE in guiding surgical strategy was 94%. All patients were alive at the time of follow up; 10 (77%) were in NYHA class I and three in class II (23%). Mitral regurgitation was severe in one patient (8%), moderate in three (23%), mild in four (31%), and absent in five (38%). No relapses of active infective endocarditis were observed during the follow up period. CONCLUSION: Mitral valve repair appears to be an effective treatment for active, acute infective endocarditis with mitral regurgitation and should be considered as a therapeutic strategy when surgery is contemplated. TEE has a fundamental role in the surgical decision-making process in these patients.

Assisted circulation for myocardial recovery after repair of congenital heart disease.

Between January 1987 and May 1990, six children underwent ventricular assisted circulation for recovery of myocardial function after cardiac surgery. Their ages ranged from 9 months to 12 years. Three patients had tetralogy of Fallot and one had atrioventricular discordance with ventriculoarterial concordance, ventricular septal defect, and under-over ventricles. Double outlet left ventricle and a large ventricular septal defect with pulmonary hypertension was present in the remaining two. The duration of circulatory support averaged 126 +/- 57 h. An extracorporeal membrane oxygenator (ECMO) was used in four patients, biventricular assistance with centrifugal pumps in one, and left ventricular assistance followed by ECMO in the last patient. Circulatory support was begun in the operating room in two patients who could not be weaned from cardiopulmonary bypass. Both these patients are long-term survivors. Assisted circulation was implanted in four patients in the intensive care unit because of low cardiac output refractory to any pharmacological treatment. Only one of these patients could be weaned from circulatory support but he died 20 days later because of multiorgan failure due to persistent poor myocardial function. The causes of death in the remaining three patients were intracranial hemorrhage, untreatable bleeding, and failure of myocardial recovery, respectively. We believe that early postoperative use of circulatory support can be a major determinant for recovery of myocardial function in patients who have severe low cardiac output following repair of congenital cardiac lesions. Our initial experience with the use of biventricular assistance in small children is encouraging. Nevertheless, further observations are clearly necessary to establish the role of postoperative circulatory support in children with congenital cardiac lesions.