Design and calibration of a Tonpilz transducer for low frequency medical ultrasound tomography.

The design and performance of a transducer for low frequency ultrasound tomography is presented, motivated by recent research demonstrating that acoustic waves transmitting at frequencies between 10 kHz and 750 kHz penetrate the lungs and may be useful for thoracic imaging. An adaptation of the traditional Tonpilz design was developed, vibrational amplitude and electrical impedance were measured, and an optimal frequency was determined. The design is found to meet the desired mechanical, electrical, and safety specifications. Thus, it was considered a promising option for the target application of pulmonary imaging with ultrasound computed tomography between 50 and 200 kHz; highest efficiency achieved around 125 kHz and 156 kHz, and beam divergence of 40°.

Protective effects of Syzygium cumini seed extract against methylmercury-induced sistemic toxicity in neonatal rats.

Syzygium cumini (L.) Skeels (Sc) belongs to the medicinal plants with an important source of phenolic compounds. Sc has been shown to possess antioxidant and anti-inflammatory properties. Methylmercury (MeHg), a highly toxic environmental pollutant, induces oxidative stress and dysfunction in many cell types. This study was aimed to evaluate the effect of aqueous seed extract of Sc (ASc) on MeHg-induced toxicity in rats. Two-day-old rats (P2) received a single dose of MeHg (10 mg/kg) and two doses of ASc (0.9 mg/kg) per os. After two days, the effects of the treatment were investigated in the cerebral cortex, hippocampus, kidney, liver and urine samples. Our results demonstrated that N-acetyl-ß-D: -glucosaminidase (NAG) activity in the kidney and urine, the lipid peroxidation levels in the liver and kidney samples, as well as the adenosine deaminase (ADA) activity in the hippocampus, kidney and liver were higher in MeHg-group when compared to the control group. The administration of ASc reverted the toxic effects of MeHg. It is noteworthy to observe that the main compounds present in the ASc, as gallic acid (the major component), chlorogenic acid and rutin, might be the responsible for such benefit, since they were found to display antioxidant properties.

Allium sativum L. extract prevents methyl mercury-induced cytotoxicity in peripheral blood leukocytes (LS).

Adenosine deaminase (ADA) is involved in purine metabolism and plays a significant role in the immune system. The focus of this investigation was to examine the effects of low concentrations of organic mercury on ADA activity in human leukocytes and to investigate the relationship between these effects and cell death. We have examined the protective potential effects of Allium sativum extract (GaE) against Methylmercury (MeHg)-induced cytotoxic effects on human leucocytes under in vitro conditions. MeHg (0.05-10 microM) significantly decreased leukocyte viability (58.97% for MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) and 51.67% for Alamar Blue (AB) and this decrease was positively correlated to the MeHg-induced inhibition of ADA activity. N-acetylcysteine (NAC) and GaE prevented both the MeHg-induced cytotoxic effects on leukocytes according to MTT and AB assays and the effects on the ADA activity. The present results suggest that the protective effects of GaE against MeHg-induced leukocyte damage is related to the removal of oxidant species generated in the presence of MeHg due to the antioxidant efficacy of garlic constituents. It is important to point out that the intense presence of ADA in Leukocyte suspension (LS) highlights the relevant effects in the immune system and in vitro cytotoxicity of MeHg exposure.

[Structural and morphometric analysis of the internal mammary artery used in coronary bypass surgery]. / Analisi strutturale e morfometrica dell'arteria mammaria interna utilizzata nel bypass coronarico.

The internal mammary artery is currently regarded as the optimal canal in coronary bypass surgery. Even if the motives for the excellent behaviour of this artery are still not fully clarified, the morphological and morphofunctional study of its wall can contribute to explain the clinical results obtained using this canal. In order to complete existing studies on this topic and to increase our knowledge of the structure of this artery, segments of internal mammary artery taken from patients undergoing coronary bypass surgery were analysed. Histological, immunohistochemical, histochemical and morphometrical tests were performed in these samples. The results of the tests underline the considerable complexity of the internal mammary artery whose walls appear to be rich in elastic fibres, divided into numerous lamellar structures concentric to the vasal lumen and without vasa vasorum in the tunica media given that this is adjacent to the tunica adventitia. Moreover, the marked presence of the NO-synthase enzyme, responsible for nitrogen monoxide synthesis, was observed in the endothelial layer and tunica media, as suggested by histochemical analysis. These data argue in favour of a structure able to resist the considerable hemodynamic stress to which the artery is subjected after bypass, a structure which is functionally well adapted to receive the majority of nutrition through its own lumen, and, lastly, a structure capable of self-regulation in response to the requirements made from time to time. These findings may further our understanding of the morphofunctional aspects of the internal mammary artery and may contribute to explaining the latter's relative immunity to atherosclerosis and, thus, its success in coronary bypass.

Reliability of immunoassays for anti-HCV antibodies (ELISA and RIBA II) in patients with essential mixed cryoglobulinemia (EMC).

The recent reports of a very high frequency of signs of hepatitis C virus (HCV) infection among patients with essential mixed cryoglobulins (EMC) suggest new hypotheses for the pathogenesis of this disease. However, most of these studies have been seriously criticized. The serologic test designed for detection of anti-HCV antibodies (ELISA, RIBA I and II) may yield a significant rate of false-positive results when performed on cryoglobulinemic sera, and the detection of the HCV genome by PCR is still heavily conditioned by practical problems. Indirect, but possibly more reliable, evidence of HCV infection in cryoglobulinemic patients might come from the demonstration of anti-HCV antibodies by a conventional technique (ELISA or RIBA) in the purified polyclonal non-rheumatoid immunoglobulinemic fraction excreted in the urine by glomerular filtration. Fifty-two patients whose serum had tested positive for HCV antibodies (by ELISA and RIBA) on multiple occasions were enrolled in this study. They were diagnosed as having either EMC or HCV chronic hepatitis without cryoglobulinemia at least one year ago. The urine samples of these patients were tested for anti-HCV antibodies by ELISA and RIBA. In patients with chronic C hepatitis the antibodies most frequently found in the serum were anti-C33c and anti-C22-3. The results of the RIBA were substantially confirmed by ELISA, with a positive test in the urine of 30 of 32 seropositive patients. Similar results were obtained in patients with EMC II. We conclude that the specificity of the RIBA and ELISA tests for HCV antibodies in patients with EMC appears to be as high as in HCV+ patients without serum cryoglobulins. EMC patients have a high incidence of HCV infection and active chronic liver disease.