Non-newtonian and flow pulsatility effects in simulation models of a stented intracranial aneurysm.

Three models of different stent designs implanted in a cerebral aneurysm, originating from the Virtual Intracranial Stenting Challenge '07, are meshed and the flow characteristics simulated using commercial computational fluid dynamics (CFD) software in order to investigate the effects of non-Newtonian viscosity and pulsatile flow. Conventional mass inflow and wall shear stress (WSS) output are used as a means of comparing the CFD simulations. In addition, a WSS distribution is presented, which clearly discriminates in favour of the stent design identified by other groups. It is concluded that non-Newtonian and pulsatile effects are important to include in order to avoid underestimating wss, to understand dynamic flow effects, and to discriminate more effectively between stent designs.

Acute thrombosis of abdominal aorta and hypercoagulable disorders.

Acute abdominal aortic occlusion (AAAO) is a rare, life threatening condition, which usually occurs in elderly patients, causing challenging management issues. In patients who have no cardiac or vascular disease this catastrophic event is very rare and is due to hypercoagulable disorders. This study reviews the literature on AAAO in hypercoagulable states in the light of our experience on a case of an acute thrombosis of nonaneurysmal, nonatherosclerotic abdominal aorta in a female patient with protein S deficiency and Sjögren's syndrome and her younger brother, which was found to have atherosclerotic involvement of distal aorta and elevation in homocysteine levels. Because of a misleading clinical presentation, the diagnosis was delayed and conservative treatment failed. Both were successfully treated with emergency aorto-bifemoral grafting. Other cases of arterial thrombosis and hypercoagulable disorders were found in first-degree relatives. Our experience and the review of the literature suggest that the interaction between host and environment factors can lead to acute thrombosis of the non-pathologic abdominal aorta; not only classic hypercoagulability disorders, but also immunologic, metabolic, toxicological cofactors can be involved. Delay in diagnosis is frequent and may not influence the prognosis, but does not allow conservative therapy. Prognosis depends mainly on pathologic cofactors that require detection and appropriate treatment in order to prevent complications and recurrences.

Ultrasound-guided percutaneous needle aspiration biopsy of peripheral pulmonary lesions.

Percutaneous needle aspiration (PCNA) biopsy of pulmonary lesions is usually performed under fluoroscopic or computed tomographic guidance. In subpleural lesions, PCNA may be performed under ultrasonographic guidance. In this study, the diagnostic results of ultrasound-guided PCNA in 45 patients with peripheral pulmonary lesions of unknown aetiology are evaluated. The overall diagnostic yield was 80% (36/45). The most important factor affecting the success rate was the nature of the lesion. The diagnostic yield was 92% (33/36) in malignant lesions, but only 33% (3/9) in benign lesions. The size of the lesions did not affect the success rate. None of the patients had complications. Ultrasound-guided PCNA is a quick cheap ionizing radiation-free procedure and may be a valid option in the diagnosis of peripheral lesions. The real-time monitoring, possibility of driving the needle into solid nonnecrotic areas and visualization of the vessels surrounding the lesions make the procedure effective and safe. The major limitation of the method is that the nodule from which a biopsy is to be taken must be close to the visceral pleura, and thus detectable by ultrasound.

Exogenous CoQ10 preserves plasma ubiquinone levels in patients treated with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.

Ubiquinone is a carrier of the mitochondrial respiratory chain which regulates oxidative phosphorylation: it also acts as a membrane stabilizer preventing lipid peroxidation. In man the quinone ring originates from tyrosine, while the formation of the polyisoprenoid lateral chain starts from acetyl CoA and proceeds through mevalonate and isopentenylpyrophosphate; this biosynthetic pathway is the same as the cholesterol one. We therefore performed this study to evaluate whether statins (hypocholesterolemic drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase) modify blood levels of ubiquinone. Thirty unrelated outpatients with primary hypercholesterolemia (IIa phenotype) were treated with 20 mg of simvastatin for a 3-month period (group S) or with 20 mg of simvastatin plus 100 mg CoQ10 (group US). The following parameters were evaluated at time 0, and at 45 and 90 days: total plasma cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglycerides, Apo A1, Apo B and CoQ10 in plasma and in platelets. In the S group, there was a marked decrease in total cholesterol low-density lipoprotein-cholesterol and in plasma CoQ10 levels from 1.08 mg/dl to 0.80 mg/dl. In contrast, in the US group we observed a significant increase of plasma CoQ10 (from 1.20 to 1.48 mg/dl) while the hypocholesterolemic effect was similar to that observed in the S group. Platelet CoQ10 also decreased in the S group (from 104 to 90 ng/mg) and increased in the US group (from 95 to 145 ng/mg).(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of survival in subjects with chronic obstructive pulmonary disease treated with long-term oxygen therapy.

We examined 166 patients with advanced chronic obstructive pulmonary disease (COPD) treated with long-term oxygen therapy (LTOT) in order to evaluate the prognostic factors of such patients. The mean observation period was 24 months (range 2-50 months) and the following variables were considered: age, forced expiratory volume in 1 s (FEV1), arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), hematocrit, right ventricular systolic pressure (RVSP; evaluated by Doppler echocardiography), number of hospitalizations in the 2 years prior to prescription of LTOT and body mass index. The overall survival rate was 78.3% at 24 months and 67.1% at 36 months. A univariate analysis identified three variables as significant predictors of survival: FEV1, PaO2 and RVSP. A multivariate analysis, using Cox's model, showed an independent predictive power for RVSP, age and FEV1. RVSP higher than 35 mm Hg, age greater than 70 years and FEV1 lower than 30% of the predicted value were associated with shortened survival. The importance of pulmonary hypertension as a predictor of death suggests that LTOT could be prescribed earlier for COPD patients with cor pulmonale, as oxygen has been shown to be the only effective therapy for improving the survival probability of these patients.

Plasma lipoprotein(a) concentration in familial hypercholesterolemic patients without coronary artery disease.

Familial Hypercholesterolemia (FH) is a condition characterized by markedly elevated blood cholesterol, low-density lipoproteins (LDL), and apolipoprotein B-100 (apo B). The molecular basis of this monogenic disease is the defective functioning of the cellular receptor for LDL that recognizes apo B. Lipoprotein(a) [Lp(a)] is a circulating lipoprotein that is structurally related to LDL, as it also contains apo B. To assess the impact of the LDL receptor deficiency on the plasma Lp(a) concentration, we measured Lp(a) in 28 FH patients and in 31 unaffected relatives. Because elevation of Lp(a) concentration in plasma of patients with coronary artery disease (CAD) appears to occur independently from plasma cholesterol levels, to avoid potentially confounding problems, members of the families chosen had no history for the disease. Whereas apo B clearly showed a bimodality of distribution by being significantly higher in the FH patients (166 +/- 38 mg/dL) than in the unaffected relatives (92 +/- 18 mg/dL), Lp(a) concentration did not differ in the two groups of patients (30 +/- 24 mg/dL in the FH patients v 31 +/- 23 in the normolipidemic relatives). Similar results were obtained when only siblings were further considered. We conclude that although Lp(a) is closely related to LDL structurally, its level in plasma is not significantly affected by the LDL receptor activity.

Pigmentary system of the adult alpine salamander Salamandra atra atra (Laur., 1768).

The pigmentary system of the skin from adult specimens of the black alpine salamander Salamandra atra atra was investigated by light microscope, electron microscope, and biochemical studies. Results were compared with those obtained in previous study of the subspecies Salamandra atra aurorae. Unlike Salamandra atra aurorae, which presents epidermal xanthophores and iridophores, Salamandra atra atra is completely melanized, presenting only epidermal and dermal melanophores. The melanosomes in both the epidermis and the dermis appear to derive from a multivesicular premelanosome similar to that in the goldfish, and the epidermal melanosomes are smaller than those in the dermis. Premelanosomes with an internal lamellar matrix were not observed. The biochemical results have shown that in the ethanol extracts obtained from the skin in toto and from the melanosomes, pteridines and flavins are always present and are the same as those extracted from the black skin areas of Salamandra atra aurorae.

Convective heat transfer coefficients in the circulation.

Convective heat transfer in the vessels of the circulatory system is investigated numerically. In the modeling, account is taken of the non-Newtonian rheological properties of blood and the presence of a cell-depleted plasma layer at the vessel wall. The latter is found to produce a remarkable enhancement of the heat transfer rate in the small vessels, while the effects due to the rheological behavior of blood are comparatively low. A comparison with experimental data available in the open literature is finally attempted.

[Prevention intervention in a Milan school situation]. / Intervento di prevenzione in una realtà scolare milanese.

The authors refer an epidemiological survey about caries and periodontal conditions of school children of some schools of the city of Milan and prevention program that will take place in the school investigated. The data presented are the starting situation of a longitudinal intervention in the committee.