In vitro comparative study on the mechanical behavior of Zirconia and Polyetheretherketone in applied dental sciences.

OBJECTIVE: Recently, Zirconia and polyaryletherketone (PEEK) have attracted increasing interest as reliable and safe materials in dental applications, mainly because of their good biomechanical characteristics. The aim of this study was to investigate the response to different loads by prosthetic frameworks for supported fixed partial dentures (FPDs), thus simulating osseointegrated implants. MATERIALS AND METHODS: The specimens were divided into two groups (n= 5 each). Group A: FDPs in zirconia-ceramic; Group B: FDPs in PEEK-composite. These 2 groups were subjected to vertical loads so to evaluate structural deformation; then, they have been analyzed by scanning electron microscopy (SEM) at different magnifications. RESULTS: In tested samples, different types of mechanical failures have been observed. In Zirconia-specimens, chipping is the main failure noticed in this study, mostly in distal margins of the structure. Also, peek-specimens show failure and fracture. CONCLUSIONS: Zirconia and PEEK could be considered both good materials, but several investigations are needed to use these materials as an alternative to metals for fixed partial dentures.

Stilbene production in cell cultures of Vitis vinifera L. cvs Red Globe and Michele Palieri elicited by methyl jasmonate.

Cell cultures obtained from Vitis vinifera cvs Michele Palieri and Red Globe were cultured in order to stimulate stilbene production. In the calli, stilbene production peaked at day 22 of culture for both cultivars; the main compound was trans-piceid, followed by cis-piceid. Methyl jasmonate, which was added to cell suspensions in the first half of the exponential growth phase, enhanced stilbene accumulation, producing mainly trans-piceid and epsilon-viniferin. Other stilbenoids, though in lower quantities, were identified by liquid chromatography/positive electrospray mass spectrometry. epsilon-Viniferin and trans-resveratrol were the main compounds released into the culture medium. The total quantity of stilbenes was genotype dependent, with a better response found for the cv Red Globe.

Chitosan enhances xanthone production in Hypericum perforatum subsp. angustifolium cell cultures.

Hypericum perforatum is an important medicinal plant containing numerous biologically active compounds. The effect of chitosan elicitation on xanthone biosynthesis in calli and in cell suspension cultures of H. perforatum subsp. angustifolium was evaluated. Elicited cell cultures showed an increase in xanthone production and a simultaneous decrease in flavonoid production. Chitosan also induced the production of 1,7-dihydroxyxanthone (euxanthone) and cadensin G, which were not detected in either the calli nor the non-elicited cell cultures. 1,7-Dihydroxyxanthone was in part (21%) released in the culture medium.

[Clearances in automated intermittent peritoneal techniques: a new formula to use morning blood sampling]. / Clearances in tecniche peritoneali automatizzate intermittenti: una nuova formula per utilizzare il prelievo ematico del mattino.

According to the main guidelines, dialysis adequacy monitoring is fundamental in the management of patients on peritoneal dialysis. In order to avoid mistakes in the calculation of the peritoneal urea and creatinine clearance in patients on dialysis with intermittent techniques, the collection of blood samples about 6 hours after the end of the dialysis session is advised. In fact, because the creatinine and urea values at the end of dialysis (the morning values in NIPD) are the lowest, the resulting clearances could be overestimated. The mean values between the start and the end of the dialysis session are considered the gold standard. However, collecting a blood sample at 2.00 p.m. may be difficult and uncomfortable both for the nurse and the patient. In this paper we present two formulas (the first for urea and the second for creatinine) which, starting from the values at the end of dialysis, predict the values at the beginning of the session and consequently the mean values. The aim of this study was to validate the formulas by evaluating their capability to predict the mean urea and creatinine values when only end-of-dialysis blood sampling was performed. Statistical analysis was carried out using the Bland-Altman test. The two formulas proved able to predict the mean urea and creatinine values; the differences between the measured and calculated values were not statistically significant.

Anthocyanins and flavan-3-ols from grapes and wines of Vitis vinifera cv. Cesanese d'Affile.

The objective of the present study was to evaluate the amount of some potential health-promoting phenols in the grape of Vitis vinifera cv. Cesanese d'Affile and in wines made from these grapes. The analyses were performed using HPLC/DAD/MS. The accumulation of anthocyanins in the skin and flavan-3-ols in the seed was determined at different stages of ripening of the grape (i.e. green, veraison, middle stage of ripening, and complete ripening). Thirteen anthocyanins were identified in the skin at all stages of ripening, except the green stage. With regard to flavan-3-ols, (+)-catechin, (-)-epicatechin, and (-)-epicatechin gallate were detected in all of the seed samples. The highest (+)-catechin content was found in the seeds of the green grape (2 mg g(-1) DW), whereas in the seeds from the completely ripe grape the content was more than ten times lower. The highest catechin content in the seed was correlated with the lowest anthocyanin content in the skin. The wines produced in the years 2004 and 2005 showed, at wavelengths of 520 and 280 nm, almost identical quali-quantitative chromatographic profiles, with high concentrations of anthocyanin 3-O-glucosides, low concentrations of acylated anthocyanins, and trace amounts of (+)-catechin and (-)-epicatechin.

CPT accumulation in the fruit and during early phases of plant development in Camptotheca acuminata Decaisne (Nyssaceae).

We describe the dynamics of camptothecin (CPT) accumulation during the early phases of plant development in Camptotheca acuminata. TLC and HPLC analyses were performed on the entire mature fruit and all of its parts and on the organs of seedlings in different developmental stages. In the mature fruit, the CPT content was relatively high (2.83 mg g(-1) DW); it was accumulated especially in the endosperm (1.82 mg g(-1) DW) and embryo (1.10 mg g(-1) DW). Regarding seedlings, CPT was present in all of the organs, at all developmental stages. In the cotyledons, content was greatest in the early developmental stages (4.23 mg g(-1) DW) and drastically decreased once the organ reached maturity (0.34 mg g(-1) DW). A similar trend was observed for the true leaves. The results suggest that CPT is translocated from the organs at an advanced developmental stage to those at an early stage.

Early experiences of intraoperative ultrasound guided angioplasty of the arterial stenosis during upper limb arteriovenous fistula creation.

In recent years the high prevalence of diabetes and atherosclerosis in elderly uremic patients starting hemodialysis (HD) has led to the increase in the risk of vascular access (VA) failure caused by pre-existing arterial diseases, including both VA slow maturation and early failure, and upper limb ischemic symptoms. Recently, in performing radial (R), brachial (B) and ulnar (U) artery (A) percutaneous transluminal angioplasty (PTA) in HD patients affected by access thrombosis, with insufficient blood flow and severe upper limb ischemia, good outcomes have been reported. Nevertheless, these procedures were performed after arteriovenous fistula (AVF) creation. About 2 years ago, we approached an intra-operative ultrasound-guided transluminal angioplasty (IUTA) performed during AVF creation, using the arterial incision, necessary because of the anastomosis, to introduce the necessary devices for the IUTA. The arterial stenosis having undergone IUTA was diagnosed by a preliminary ultrasound examination. Ultrasound guidance during the procedure is necessary for correct balloon location in the stenosis site. We treated seven patients (four diabetics), mean age 76 + 5 yrs. In all cases, the radial arteries because of hyposphygmia, were unfit for AVF creation. Four distal radio-cephalic AVFs at the wrist were created in patients 1, 3, 4 and 5; in the other three patients (2, 6 and 7), with failure or thrombosis of previous distal AVFs, an immediately upstream anastomosis was performed. In all cases, first, the area selected to perform the AV anastomosis was exposed, then the AR was incised, and the introductory metallic guide wire and the angioplasty catheter (with dimensions decided after PUS), were introduced. The balloon was inflated to 8-13 atm for 30-35 sec. In two patients a stent was also positioned. Later, a side-to-side AVF was created, closing the distal venous vessel. Patient follow-up ranged from 6-22 months. The ultrasound evaluation after IUTA showed the correction of all the stenosis treated. AVF maturation was good, except for the stented ones, which were inadequate. In conclusion, our early experience shows IUTA could be an adequate and effective procedure allowing the use of the stenotic arteries (otherwise unsuitable) for AVF creation. In our experience, stenting after IUTA does not add any other advantages.

Ultrasound guided brachial arterial angioplasty during the creation of a radio-cephalic arteriovenous fistula: a case report.

UNLABELLED: To prevent arteriovenous fistula (AVF) early failure, due to radial or brachial artery stenosis, ultrasound guided angioplasty performed while surgically creating the AVF could be an effective procedure. CASE REPORT: A 76-year-old diabetic male patient, on hemodialysis (HD) for 15 months, presented extensive thrombosis of the radio-cephalic AVF at the right arm, which had lasted for about 10 days. Ultrasound examination showed a 40% brachial artery stenosis with eccentric calcified plaque. The stenosis was localized about 1.5 cm before the artery bifurcation. The brachial artery diameter was 0.45 cm before and 0.26 cm at the level of the stenosis, the latter being 0.45 cm long. At the left wrist, under local anesthesia, the radial artery and the cephalic vein were exposed; the radial artery was then longitudinally incised for 7-8 mm in the area selected to create the AVF. A 6 Fr introducer, a metallic guide wire and a catheter for angioplasty were inserted one after the other in the radial artery. When the correct position of the angioplasty catheter in the stenotic area was established by ultrasound examination, the balloon was blown up to 13 atm for 35 sec, reducing the stenosis from 40-20%. Finally, a side-to-side radio-cephalic fistula was created, legating the distal vein. The AVF was used for HD after 3 weeks. The follow-up at 6 months demonstrated fair access performance and it was used without problems. Our satisfactory experience suggests that ultrasound guided angioplasty of brachial artery stenosis, performed simultaneously with surgical AVF creation, is possibly a successful procedure. This technique reduces the risk of early AVF failure and also allows, when required, stent implantation.

Cellular localisation of the anti-cancer drug camptothecin in Camptotheca acuminata Decne (Nyssaceae).

In Camptotheca acuminata, we studied the cellular sites of accumulation of the alkaloid camptothecin (CPT), in both plants grown in the field and those grown in a greenhouse, subjecting the latter to stress (i.e., draught, nutritional deficit, and pruning). Fresh sections of the leaf, stem, and root were analysed for the presence of CPT by examining the autofluorescence that the CPT molecule emits when exposed to UV radiation. In the plants grown in the field, CPT was observed only rarely. In the greenhouse plants, CPT had accumulated in crystalline form in the vacuole of specialised cells (i.e., segregator idioblasts), which were not morphologically distinguishable from the cells of the surrounding tissues. In the organs examined, the segregator idioblasts were localised in parenchymatic and epidermal tissues. CPT crystals were also detected in the glandular trichomes on both the stem and leaf.

[The cellular and molecular bases of "tooth framing"]. / Le basi cellulari e molecolari della "costruzione" dei denti.

Progress in molecular biology in recent years has enormously increased interest in tooth generation. The enamel knot has been discovered, in consequence. This is a transient structure acting as molecular signaling center, responsible for controlling cusp formation, stimulating growth of surrounding epithelium, and generating new knots or their disappearance through apoptosis. Both tooth development and enamel knots are regulated by a cascade of gene activity where Fgf4, Shh, BMP4, Lef1 and p21 are the prime movers of the processes. Homeobox genes (Msx, Dlx) are the orchestrators of the framing and a series of proteins (adhesion molecules, extracellular matrix components) are the executors of "tooth framing". An important concept has emerged from developmental biology through the identification of the basic mechanisms involved in tooth development: the molecular basis of structure framing shares common rules. Thus similar genetic programs are involved in body structure generation (limb bud, tooth, branching morphogenesis). A deeper understanding of developmental rules regulating tooth formation will make it possible in the near future: a) to modify in vivo homeobox gene expression and restore tooth generation hampered by tooth agenesia due to homeobox gene deregulation; b) to induce complete tooth formation, in case of tooth loss due to trauma or diseases, through implantation in the patient's oral cavity of a synthetic ball containing morphogens and growth factors to stimulate, in the right spatio-temporal sequence, the entire tooth genetic cascade. These concepts will certainly enforce cultural and practical interaction between biology and dentistry.