Free propagation phase-contrast breast CT provides higher image quality than cone-beam breast-CT at low radiation doses: a feasibility study on human mastectomies

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis.

Association between the oxidative status, Vitamin D levels and respiratory function in asthmatic children

AIM

We studied the relationship between plasma concentrations of oxidative system markers, vitamin D, and respiratory functions in children with asthma.

MATERIALS AND METHODS

Ninety one children aged 6-17 years with stable asthma seen in the clinic had the serum concentrations of oxidative system markers [total antioxidant capacity (TAC), total oxidative status (TOS), paraoxonase-1 activity (PON-1), and 25-hydroxyvitamin D3] and respiratory functions were measured.

RESULTS

There was no statistical correlation between TAC and age and FEV1. There was a significant positive correlation between TAC and 25(OH)D3 (r = 0.214, P = 0.021), TAC and TOS (r = 0.218, P = 0.007), TAC and PON-1 (r = 0.230, P = 0.028), TAC and IgE (r = 0.194, P = 0.033), and inverse correlation between TAC and PEF (r = -0.208, P = 0.024). In the backward multiple regression analysis, 25(OH)D3 (t = 2.613, P = 0.011), age (t = -2.158, P = 0.034), TOS (t = 2.158, P = 0.000), and OSI index (t = -13.859 P = 0.000) maintained an independent relationship with TAC (r = 0.858, r2 = 0.737, F = 21.436, P = 0.000).

CONCLUSION

Oxidative stress correlates with the serum vitamin D concentrations. Clinical trials are required to confirm that increasing serum 25OHD may improve asthma control, as measured by clinical and oxidative stress markers.

The compromise of dynamic disulfide/thiol homeostasis as a biomarker of oxidative stress in trichloroethylene exposure

In this study, we aimed to investigate disulfide/thiol homeostasis in trichloroethylene (TCE) exposure. The study was carried out in 30 nonsmoker TCE-exposed workers with a variety of occupations. Additionally, 30 healthy nonsmoker volunteers were recruited as the control group. TCE exposure was determined by measuring urinary trichloroacetic acid (TCA) concentration. Median urinary TCA levels of exposed workers (20.5 mg/L) were significantly higher than control subjects (5 mg/L). Thiol and disulfide concentrations were determined using a novel automated method. Disulfide/thiol ratio was significantly higher in the exposed group ( p < 0.001). Thiol/disulfide homeostasis was found to be disturbed in TCE-exposed workers. We predict that in TCE-exposed workers this disturbance can be a therapeutic target, and the efficiency of the treatment can easily be monitored by the novel method we used.

An analog of the natural steroidal alkaloid cortistatin A potently suppresses Tat-dependent HIV transcription

The human immunodeficiency virus type 1 (HIV) Tat protein, a potent activator of HIV gene expression, is essential for integrated viral genome expression and represents a potential antiviral target. Tat binds the 5'-terminal region of HIV mRNA's stem-bulge-loop structure, the transactivation-responsive (TAR) element, to activate transcription. We find that didehydro-Cortistatin A (dCA), an analog of a natural steroidal alkaloid from a marine sponge, inhibits Tat-mediated transactivation of the integrated provirus by binding specifically to the TAR-binding domain of Tat. Working at subnanomolar concentrations, dCA reduces Tat-mediated transcriptional initiation/elongation from the viral promoter to inhibit HIV-1 and HIV-2 replication in acutely and chronically infected cells. Importantly, dCA abrogates spontaneous viral particle release from CD4(+)T cells from virally suppressed subjects on highly active antiretroviral therapy (HAART). Thus, dCA defines a unique class of anti-HIV drugs that may inhibit viral production from stable reservoirs and reduce residual viremia during HAART.

Selective imidazolidine ring opening during complex formation of iron(III), copper(II), and zinc(II) with a multidentate ligand obtained from 2-pyridinecarboxaldehyde N-oxide and triethylenetetramine

The condensation of 2-pyridinecarboxaldehyde N-oxide and triethylenetetramine yields a product with two imidazolidine rings, as proven by a solid-state X-ray structure analysis as well as by NMR solution spectra. This ligand, L1, undergoes a ring-opening reaction on complex formation with Cu(II), yielding [CuL2]2+ where L2 functions as a pentadentate ligand, containing only one imidazolidine ring. On complexation with Zn(II) and Fe(III), both rings are opened and the complexes [ZnL3]2+ and [FeL3]3+ with a hexadentate L3 ligand are formed. The recrystallization of [ZnL3]2+ from DMSO solution results in the complex [ZnL1(DMSO)2]2+ in which L1 behaves as a tetradentate ligand. Thus L1, L2, and L3 are structural isomers with two, one, or no imidazolidine rings, as confirmed by X-ray structure analyses. The intramolecular ring formation is the result of the nucleophilic addition of the N(amino) group to the electrophilic sp2-hybridized -HC delta+=N site. Owing to the absence of the chelate effect on the sp3-hybridized carbon atom belonging to the imidazolidine ring, the ring opening is facilitated and readily observed upon complex formation with Cu(II), Zn(II), and Fe(III).

[Adverse effects of the work process in relation to pregnancy]

Some characteristics of the working activity of pregnant women were investigated during statistical analysis of data pertaining to 6166 naturally terminated pregnancies in the Gottwaldov district (1981-1983). The threatening element from the aspect of spontaneous abortions in the first trimester is work done during most of the shift in a standing position without movement. There also the highest incidence of small-for-age and hypotrophic foetuses was found. Work involving constant movement is a risk and may lead to premature delivery. Manipulation with loads threatens pregnancy by reproductive losses (in particular a higher incidence of haemorrhage during the first trimester) and by prematurity. Social tension at the place of work also threatens pregnancy - at conflict in work places a significantly increased risk was proved. It was also proved that it is important to respect medical recommendation to transfer pregnant women to other work. As to associated factors, commuting was investigated and its adverse effect is particularly apparent when the distance is more than 25 km.

[The occupation of the pregnant woman in relation to the course and outcome of pregnancy]

Some occupations are associated with an extra risk during pregnancy. Intensive action is not involved (the relative risk does not exceed the value of 2,000) but with regard to the number of women in these categories it is a significant extensive factor. Based on the results of an analysis of a group of all naturally terminated pregnancies in the district of Gottwaldov in 1981-1983 (6166 pregnancies), as compared with the mean an increased ratio of reproductive losses was recorded in charwomen, hairdressers, teachers, engineers with university education. Prematurity was recorded in particular in waitresses, shop-assistants, nurses, other health workers and women doctors. Workers on the whole have relatively favourable results, however, the risk in these occupation more frequently develops into actual failure of pregnancy (haemorrhage in the 1st trimester, imminent premature child birth). These workers are also more protected by legal leave after a previous childbirth, as compared with other occupations.

The Convergence of Computing and Telecommunications Systems

Since we do not know of any completely workable solutions to the problems we have considered, we shall settle for a few general observations: 1) The public availability of socially useful computer communications services is and has been held back by legal battles that are now under way between the potential suppliers. 2) No simple resolution of these issues in the near future seems likely in view of the past conceptual separation of computers and communications doctrines. 3) The current policy is to determine whether the nation shall or shall not have certain computer communications services, by the adversary process. In this process, often only the voices of the loudest adversary suppliers are heard. 4) Although there can be no certainty that better alternatives cannot be devised, we believe that such a possibility assumes a higher probability if the key actors come from the technical community sectors more representative of the future consumers. 5) If we are to have the new services that are possible, we need an approach that makes better use of the technologists' dreams and goals rather than have future prospects excessively bound by lawyers paid to preserve the interests of their clients, irrespective of any secondary consequences. 6) We cannot be sanguine about this possibility, as technological statesmanship is too easily corrupted by the same forces that have placed us in this predicament. Furthermore, even if not corrupted, beneficial cooperation can too readily be regarded as simply collusion. 7) Although we do not have any clear answer, we do know that present approaches are not taking us where we want to go very rapidly and that alternative approaches should at least be considered.