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Biomedical subjects

G Donati

Publications and source records attributed to G Donati.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Treatment according to "evidence-based medicine" of aged-related exudative age-related macular degeneration (laser photocoagulation and photodynamic therapy)].

INTRODUCTION: Age related macular degeneration (AMD) is actually the leading cause of severe visual acuity loss in people over 65 in the Western World. Most of the visual loss is due to choroidal neovascularization (CNV). METHODS: Review of the literature. RESULTS: For more then 10 years laser photocoagulation was the only proven treatment for selected cases of AMD according to the evidence based medicine criteria. In 1999 photodynamic therapy was proven to be efficient for the treatment of predominantly classic subfoveal CNV. CONCLUSION: Laser photocoagulation and photodynamic therapy constitute therefore the only evidence based medicine treatment available for CNV in AMD.

Choroidal Neovascularization↗
PubMed2001

[Value of indocyanine green angiography in detection of central serous chorioretinopathy].

INTRODUCTION: Central serous chorioretinopathy (CSC) is a relatively common and self-limited disease affecting more commonly young adult males who are likely to have a type A personality. The aim of our study was to analyze indocyanine green (ICG) angiographic findings in CSC and correlate them with the biomicroscopical and Fluoresceine angiography (FA) findings in the affected and non affected eyes. PATIENTS AND METHODS: Our study included 19 consecutive patients, that were affected by CSC. The mean age of the patients was 44 years (range 35-50 years). In thirteen patients, in one eye typical acute lesions were observed, and in six patients presented chorioretinal inactive lesions. Angiographic ICG and FA findings of both eyes were compared. RESULTS: In 13 eyes (68%) presenting with the active form of CSC a classic focal leak with a smokestack phenomenon was seen in FA. The leaking point was identified in both FA and ICG, in 9 out of 13 eyes (70%). Surrounding the FA leaking point, an hyperfluorescent plaque in ICG was associated in 12 out of 13 (92%) eyes with active lesions. In 8 out of 13 (62%) controlateral eyes of this group, hyperfluorescent plaques in ICG were also observed. All eyes with inactive FA lesions (6 out of 6), expressed an hyperfluorescent plaque in ICG. DISCUSSION: ICG hyperfluorescence appears in the affected and the fellow eyes in areas where no clinical or FA signs of active disease were present. The persistence of abnormal ICG findings in all the cases of inactive disease suggest that CSC could be not a recurrent but a chronic disease.

Adult↗
PubMed2001

Influence of liver fibrosis on hepatic artery Doppler resistance index in chronic hepatitis of viral origin.

BACKGROUND: Hepatic arterial Doppler sonography is increasingly being used in liver diagnostics. The determinants of the elevation of hepatic artery impedance indexes in chronic liver disease, however, have still not been fully clarified. The aim of the present study was to investigate the relationship between histological alterations and liver circulation in chronic hepatitis. METHODS: Hepatic artery resistance index and portal flow velocity were measured using Doppler sonography in 47 patients with chronic hepatitis of viral origin diagnosed at histopathology. The patients were divided into two groups, those with mild and those with severe alterations, in accordance with the various histological parameters of the Knodell scoring system. RESULTS: Hepatic artery resistance index and age were higher in patients with more severe liver fibrosis (respectively 0.638 +/- 0.084 and 39.0 +/- 10.9 (years) in mild fibrosis versus 0.687 +/- 0.060 and 49.4 +/- 14.4 (years) in severe fibrosis; P < 0.05 for both), whereas no difference between the two groups was found for the other histological features (degeneration, inflammation and necrosis), nor for portal flow velocity. CONCLUSIONS: The increase in hepatic artery resistance index appears to be influenced by the extent of fibrous tissue deposition in the liver, determined by chronic inflammation and repair and, secondly, by ageing.

Female↗
PubMed2001

Intra- and post-dialytic platelet activation and PDGF-AB release: cellulose diacetate vs polysulfone membranes.

BACKGROUND: During haemodialysis the blood-membrane contact causes a release of platelet granule content, which contains platelet-derived growth factor AB (PDGF-AB). In view of the potential role of this in altering biocompatibility during haemodialysis, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during haemodialysis sessions performed with cellulose diacetate (CDA) and polysulfone (PS) membranes respectively. METHODS: PDGF-AB, platelet factor 4 (PF4), beta thromboglobulin (betaTG), and mean platelet volume (MPV) levels were determined in 30 patients, each of whom underwent six dialysis sessions: three with a CDA and three with a PS membrane. Blood samples were taken at times 0, 15, 30, 120, 180, and 240 min during dialysis and at 1, 4, and 20 h after the end of the session. Statistical analysis was performed using a one-way ANOVA and Student's t test. RESULTS: PDGF-AB at 15 min was increased to +41+/-9% with CDA vs +20+/-5% with PS (P<0.001) from the T0 values, and at 120 min it was +19+/-8% with CDA vs -25+/-9% with PS (P<0.001) from T0 levels. At 240 min it was +95+/-14% with CDA vs +49+/-15% with PS (P<0.001) from the T0 values, returning to basal only 20 h after the end of the session. betaTG at 15 min was +60+/-8% for CDA vs +24+/-7.5% for PS (P<0.001) from the T0 values. PF4 showed a similar trend to betaTG. MPV at 30 min from the start of dialysis was 7.4+/-0.3 fl with CDA and 8+/-0.3 fl with PS (P<0.001), and at 240 min MPV was 7.9+/-0.3 fl with CDA and 8.4+/-0.3 fl with PS (P<0.001). CONCLUSIONS: Platelet activation and platelet release reactions are lower with PS than with CDA membranes. PDGF-AB, released during and after dialysis, represents a clear biocompatibility marker. Its slow return to basal values and its action on vascular cells make it a potential risk factor for atherosclerosis in uraemic patients.

Biocompatible Materials↗
PubMed2001

Spontaneous echo-contrast as an in vivo indicator of rheological imbalance in dilatative cardiomyopathy.

The aim of this study was to evaluate coagulative and hemorheologic assessment in patients with dilatative cardiomyopathy with or without spontaneous echo contrast (SEC). We studied 45 patients, 35 males and 10 females (mean age 72.1 +/- 9.2). We measured whole blood viscosity, plasmatic fibrinogen, prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer and red cell morphology with Zipursky-Forconi method. Transthoracic and transesophageal echocardiography was performed in all patients to evaluate the presence of SEC in left atrium. We divided all the patients into two groups: the 1st group of 20 patients with SEC and Atrial Fibrillation (AF) in 80% of cases, and the 2nd group of 25 patients without SEC and AF in 31%. Our results show that in patients with SEC there is a statistically significant increase of whole blood viscosity and plasma fibrinogen in comparison with patients without SEC. Red cell morphology in all patients demonstrates a reversed EMI. D-Dimer, was out of the normal range in about 1/3 of the patients in both groups. An analysis of our results points out that in patients with SEC and AF, with a major risk factor for cardioembolic stroke, we have alterations of hemorheologic assessment with an increase of whole blood viscosity and fibrinogen that seems to be caused by an increase of red cells aggregability favoured by fibrinogen. Our conclusions are that SEC in patients with dilatative cardiomyopathy and AF is an important in vivo indicator of hemorheologic imbalance and an important marker for cardioembolic risk stroke evaluation.

Aged↗
PubMed2001

[Alkylphenols: assessment of risks for aquatic ecosystems and for human health with particular reference to endocrine effects].

(Alkylphenols: evaluation of the risk to aquatic ecosystems and human health with reference to endocrine effects).--Endocrine disrupting chemicals (EDC) are a heterogeneous group of substances that can interfere with many endocrine functions. Their effects have been demonstrated in different taxa and they are suspected to affect human health. Alkylphenols are an important group of EDC. They are formed from the degradation of alkylphenol polyethoxylates in the environment or in the sewage treatment plants. They are generally characterized by a high bioconcentration factor (BCF) and accumulate both in sediments and aquatic species. Alkylphenols (APE) show estrogenic activity: studies on fish and rodents put into evidence on both reproductive and developmental effects. In a recent study, the levels of APE detected in seafood from the Adriatic Sea showed a no negligible human health risk for strong fish consumers.

Animals↗
PubMed2000

A preliminary study of photodynamic therapy using verteporfin for choroidal neovascularization in pathologic myopia, ocular histoplasmosis syndrome, angioid streaks, and idiopathic causes.

OBJECTIVE: To evaluate short-term safety and the effects on visual acuity and fluorescein angiography of single or multiple sessions of photodynamic therapy with verteporfin for choroidal neovascularization (CNV) not related to age-related macular degeneration (AMD), including pathologic myopia, the ocular histoplasmosis syndrome, angioid streaks, and idiopathic causes. DESIGN: A nonrandomized, multicenter, open-label, dose-escalation phase 1 and 2 clinical trial. SETTING: Four ophthalmic centers in Europe and North America providing retinal care. PARTICIPANTS: Thirteen patients with subfoveal CNV due to pathologic myopia, the ocular histoplasmosis syndrome, angioid streaks, or idiopathic causes. METHODS: Standardized protocol refraction, visual acuity testing, ophthalmic examinations, color photographs, and fluorescein angiograms were used to evaluate the results of photodynamic therapy treatments with verteporfin. Follow-up ranged from 12 weeks for patients who were treated once to 43 weeks for patients who were treated up to 4 times. RESULTS: Verteporfin therapy was well tolerated in patients with CNV not related to AMD. No deterioration in visual acuity was observed; most patients gained at least 1 line of vision. Reduction in the size of leakage area from classic CNV was noted in all patients as early as 1 week after verteporfin therapy, with complete absence of leakage from classic CNV in almost half of the patients. Improvement in visual acuity after verteporfin therapy was greatest (+6, +8, and +9 lines) in 3 patients with relatively poor initial visual acuity (between 20/200 and 20/800). Up to 4 treatments were found to have short-term safety even with retreatment intervals as short as 4 weeks. CONCLUSIONS: Treatment of CNV not related to AMD with verteporfin therapy achieves short-term cessation of fluorescein leakage from CNV in a small number of patients without loss of vision. Further randomized clinical trials including a larger number of patients are under way to confirm whether verteporfin therapy is beneficial for subfoveal CNV not related to AMD.

Adult↗
PubMed2000

Diurnal changes of fibrinolysis in patients with liver cirrhosis and esophageal varices.

Variceal bleeding, whose triggering mechanisms are largely unknown, occurs with a circadian rhythmicity, with 2 peaks, one greater, in the evening, and one smaller, in the early morning. We assessed some clotting and hemodynamic parameters, possibly involved in variceal hemorrhage, over a 24-hour period, at 4-hour intervals, in 16 patients with cirrhosis and esophageal varices and in 9 controls. At each time interval, tissue plasminogen activator (tPA) and tPA inhibitor-1 (PAI-1) antigens and activities and total euglobulin fibrinolytic activity were determined and portal-vein flow velocity, volume, and congestion index were measured by duplex-Doppler. Significant circadian rhythms were searched for by least-squares and cosinor methods. tPA activity showed a circadian rhythm in cirrhosis, with a peak of 2.85 times the trough value, calculated at 18:42, and remained over 2.5-fold until shortly after 22:00. Total fibrinolytic activity showed a similar pattern, which was statistically significant also in controls. tPA and PAI antigens also showed significant circadian rhythm both in controls and cirrhotics, with higher values in the morning. Among the portal hemodynamic parameters only the congestion index showed significant rhythmic changes and only in cirrhosis, with the highest values in the late evening, but with limited diurnal excursion (+/- 5.5%). In conclusion, we showed the existence of a circadian rhythm of fibrinolysis in cirrhosis, whose temporal distribution might suggest a role of fibrinolysis in variceal hemorrhage on the basis of the comparison to the known chronorisk of variceal bleeding.

Blood Flow Velocity↗
PubMed2000

Early postnatal Müller cell death leads to retinal but not optic nerve degeneration in NSE-Hu-Bcl-2 transgenic mice.

Topographically localized over-expression of the human Bcl-2 protein in retinal glial Müller cells of a transgenic mice (line 71) leads to early postnatal apoptotic Müller cell death and retinal degeneration. Morphological, immunohistological and confocal laser microscopic examination of transgenic and wild-type retinas were achieved on paraffin retinal sections, postnatally. Apoptosis occurs two to three days earlier in the internal nuclear layer of transgenic retinae, than in wild-type littermates. In parallel there was a progressive disappearance of transgenic Hu-Bcl-2 over-expression, as well as of the Müller cell markers, cellular retinaldehyde-binding protein and glutamine synthetase. This phenomenon led to retinal dysplasia, photoreceptor apoptosis and then retinal degeneration and proliferation of the retinal pigment epithelium. The optic nerve, however, remains intact. Two complementary observations confirm the pro-apoptotic action of Bcl-2 over-expression in Müller cells: (i) in the peri-papillary and peripheral regions where the transgene Bcl-2 is not expressed, cellular retinaldehyde-binding protein or glutamine synthetase immunostaining persist and Müller glia do not die; and (ii) the retina conserves a normal organisation in these two regions in spite of total retinal degeneration elsewhere. We conclude that retinal dysplasia and degeneration are linked to primary Müller cell disruption. Besides its generally accepted anti-apoptotic function, over-expression of Bcl-2 also exerts a pro-apoptotic action, at least in immature Müller glia. One may suppose that Bcl-2 translocation resulting in its over-expression in retinal Müller cells could be a putative mechanism for early retinal degeneration.

Aging↗
PubMed2000

Frontal nonconvulsive status epilepticus associated with high-dose tiagabine therapy in a child with familial bilateral perisylvian polymicrogyria.

PURPOSE: Antiepileptic drugs are known to exacerbate absence and myoclonic seizures, especially in patients with idiopathic generalized epilepsies. Exacerbation of nonconvulsive generalized seizures in patients with partial epilepsy is less common. Recently, however, a number of cases of putative generalized nonconvulsive status epilepticus (NCSE) or NCSE without further specification have been reported in patients with chronic partial epilepsy treated with the gamma-aminobutyric acid reuptake inhibitor tiagabine. Although complex partial status epilepticus during tiagabine therapy has also been reported, possible precipitation of NCSE specifically associated with frontal lobe discharges does not appear to have been recognized. In this communication, we describe the case of a boy with familial bilateral perisylvian polymicrogyria who developed frontal NCSE after being stabilized on high-dose tiagabine METHODS: A 12-year-old boy with familial bilateral perisylvian polymicrogyria, mental retardation, and refractory partial seizures was administered tiagabine in addition to sodium valproate. The tiagabine dosage was increased gradually up to 10 mg t.i.d. (1 mg/kg per day), resulting in complete seizure control. RESULTS: After 1 week on maintenance treatment, seizures were completely controlled, but the child developed hypoactivity, decreased reactivity, and affective detachment. An EEG recording revealed subcontinuous sharp-wave discharges with irregular runs of atypical spike-wave complexes over the anterior regions of both hemispheres, consistent with a diagnosis of frontal NCSE. A reduction in tiagabine dosage to 15 mg/day led to complete regression of the behavioral and affective changes and to disappearance of the subcontinuous EEG discharges. CONCLUSIONS: Although tiagabine-induced NCSE has been described previously, particularly in patients with preexisting spike-wave abnormalities, this is the first report that identifies its potential role in the precipitation of frontal NCSE.

Anticonvulsants↗
PubMed2000

Macular epiretinal membranes.

Epiretinal membranes (ERM) are a common finding in older patients. Although they may be associated with numerous clinical conditions, most epiretinal membranes occur in the absence of ocular pathology. Patients symptoms range from asymptotic to complaints of severe vision loss and metamorphopsia. Epiretinal membranes are commonly classified according to their density, to the severity of retinal distortion and to associated biomicroscopic changes. Pars plana vitrectomy has been found to be effective in removing ERM from the macula, improving the visual acuity and decreasing metamorphopsia. Both idiopathic and secondary ERMs do well after surgery, although secondary ERMs showed a greater amount of improvement than idiopathic ones. Complications are frequent including accelerated postoperative nuclear sclerosis, retinal breaks and RD, macular edema, RPE and, occasionally, macular hole and hypotony. However only RD involving the macula have a worsening prognosis on final outcome.

Epiretinal Membrane↗
PubMed2000

[Laser photocoagulation of occult choroidal neovascularization guided by angiography using indocyanine green. A pilot study].

PURPOSE: Age related macular degeneration (AMD) is the most common cause of legal blindness in the Western world in people over 50 years of age. The most severe visual loss occurs in patients with AMD complicated by choroidal neovascular membranes (CNV). Indocyanine green angiography (ICG) account for visualization in up to 60% of the cases that are classified as occult on fluorescein angiography (up to 70% of the cases). ICG-guided laser photocoagulation of CNV is currently a mater of debate. We conducted a pilot study to determine wether it could be beneficial for patients presenting with occult CNV on fluorescein angiography. MATERIAL AND METHODS: Twenty consecutive patients (20 eyes) with occult CNV in AMD were included. All showed occult CNV on fluorescein angiography and a well defined juxta- or extrafoveal hot spot or plaque hyperfluorescence on ICG. Fibrovascular retinal pigment epithelial detachments were excluded. The patients had serial controls, including fluorescein angiography and ICG, at 15 days, 1, 2, 3, 6, 9 and 12 months after photocoagulation. RESULTS: At the end of follow-up visual acuity (VA) was stable (within +/- 3 lines) compared to the initial one in 80% (16) of the cases. A complete resolution of exudative signs was observed in 75% (15) of the cases. CONCLUSIONS: ICG-guided laser photocoagulation of occult CNV in AMD account for better visual acuity than natural course of the disease at 12 months follow-up. However, a prospective randomized clinical trial is warranted to evaluate definitively this treatment approach.

Aged↗