Mediastinal pseudotumor

A case of mediastinum vascular abnormality is presented consisting in the right side location of the aortic crutch and descending aorta. Besides an abnormality of brachiocephalic trunk issue and position is described. The possible diagnosis errors are discussed.     

Artefacts due to static electricity in a dental school

The diagnostic usefulness of radiographs is diminished by errors of film handling, and retakes mean increased radiation doses. Avoiding artefacts due to static electricity is part of a quality assurance programme. The number of types of artefacts originating from static electricity in the Department of Radiology, School of Dentistry, Copenhagen, were recorded over a five-week period with low temperatures and low air humidity. During the period 3137 intra-oral and 638 extra-oral films were processed by seven assistants and a number of trainees. A total of 48 artefacts on 47 extra-oral films was observed. The artefacts were classified into four types. Only one case of classical 'lightning' was found, while nine were of a hitherto undescribed type ('animals' or 'cactus flowers'). The most common type appeared as dots arranged in straight lines; their origin was obscure, but it was suspected that they were caused by the processing machine. The one typical 'lightning' case occurred on a Status-X film, consistent with the theory that friction may be a causative factor. Although individual frequencies varied, all the radiography assistants and trainees were associated with the artefacts recorded.     

Professional groups with a close irradiation dose distribution

RMAPO. O. G. Pol'skii, A. I. Sobolev, and L. F. Verbova. Moscow Scientific and Industrial Association "Radon". Translated from Atomnaya énergiya, Vol. 79, No. 2, pp. 145–152, August, 1995.     

A clinical retrospective evaluation of FA/HA coated (Biocomp) dental implants. Results after 1 year

The development of ovulation-inducing drugs has enabled clinicians to more effectively treat the hypothalamic, pituitary, and ovarian abnormalities resulting in infertility. Pregnancy rates have been improved with the use of agents such as clomiphene citrate (CC), human menopausal gonadotropin [hMG or follicle-stimulating hormone (FSH) preparations], with gonadotropin-releasing hormone (GnRH) and its analogs, stimulating the development of multiple ovarian follicles and increasing the number of fertilizable oocytes. The use of these drugs is not without certain detrimental or "toxic" consequences. The negative effects from superovulation can occur during follicle development, decreasing the number of healthy oocytes and embryos capable of leading to viable pregnancy. Ovulation induction can lead not only to higher incidences of spontaneous abortions, and multiple and ectopic pregnancies, but also to poor pregnancy rates, due, in part, to asynchrony between embryonic development and the uterine environment. Diseases such as ovarian hyperstimulation syndrome (OHSS), resulting in the secretion of supraphysiologic levels of estradiol, can lend to severe health complications, possibly requiring hospitalization. Most drugs used for ovulation induction can lead to OHSS. Although incidences of OHSS following CC use are less frequent, CC has been associated with hot flushes, multiple gestations, visual disturbances, cervical mucus abnormalities, and luteal phase deficiency. Finally, there are reports that link any or all of the ovulation-inducing drugs with a higher incidence of ovarian and breast cancer, however, a cause-effect relationship has yet to be proven.     

The participation of the serotoninergic system in regulating the activity of the central glutamatergic/aspartatergic and GABA-ergic synapses

Selective lesion of the serotoninergic system diminished the synaptic uptake of 3H-L-glutamic acid and 3H-DL-aspartic acid, as well as the Na+(-dependent) binding of 3H-L-glutamic acid in the cortex and the brain stem. The data obtained suggest an ability of the serotoninergic system to modify presynaptic processes in amino-acidergic neurons of the CNS.     

Substituted glycals as probes of glycosidase mechanisms

D-Glucal and a series of substituted derivatives have been tested as substrates, inhibitors and inactivators of the Agrobacterium faecalis beta-glucosidase in order to probe structure/function relationships in this enzyme. D-Glucal is shown to be a substrate (kcat = 2.3 min-1, Km = 0.85 mM) undergoing hydration with stereospecific protonation from the alpha-face to yield 2-deoxy-beta-D-glucose. 1-Methyl-D-glucal surprisingly serves as only a poor substrate (kcat = 0.056 min-1, Km = 57 mM), also undergoing protonation from the alpha-face. 2-Fluoro-D-glucal, however is completely inert, as a result of inductive destabilisation of the oxocarbenium ion-like transition state for protonation, and functions only as a relatively weak (Ki = 24 mM) inhibitor. Similar behaviour was seen with almond beta-glucosidase and yeast alpha-glucosidase and for the interaction of 2-fluoro-D-galactal with Escherichia coli beta-galactosidase. A series of of alpha, beta-unsaturated glucal derivatives was also synthesised and tested as potential substrates, inhibitors or inactivators of A. faecalis beta-glucosidase. Of these only 1-nitro-D-glucal functioned as a time dependent, irreversible inactivator (ki = 0.011 min-1, Ki = 5.5 mM), presumably acting as a Michael acceptor. Electrospray mass spectrometric analysis revealed multiple labeling of the enzyme by this inactivator, lessening its usefulness as an affinity label. Less reactive Michael acceptor glycals which might have been more specific (1-cyano-, 2-cyano-, 1-carboxylic acid, 1-carboxylic acid methyl ester) unfortunately did not function as inactivators or substrates, only as relatively weak reversible inhibitors (Ki = 3-96 mM).     

Radionuclides in the Kara sea bottom sediments

The contents and distribution of natural (214Pb, 214Bi, 228Ac, and 208Tl) and technogenic (90Sr, 137Cs, and 60Co) radionuclides in the Kara Sea bottom sediments was analyzed by using the materials collected by R/V "Pomor" (Murmansk Marine Biological Institute). In 1994, no high (critical) concentrations of technogenic radioisotopes were found in the sea sediments, while the spots (regions) of elevated 137Cs content found in 1984 were not confirmed in 1994. It was proposed that the main sources of entry of technogenic radionuclides in the sea sediments in the last years are the flow of the Ob'-Yenisei waters and container burials of radioactive waste in the sea, which appeared to have been markedly corroded. The latter is confirmed by detection in some places of 60Co, which was not previously found in the sediments.     

Studies in Germanium Oxide Systems: I, Phase Equilibria in the System Li2O—GeO2

Phase equilibrium relations in the system Li₂O-GeO₂ were determined using standard quenching techniques. In contrast to published literature five congruently melting compounds were found to exist. They are Li₂O·7GeO₂, 3Li₂O O·8GeO₂, Li₂O O·GeO₂, 3Li₂O O·2GeO₂, and 2Li₂O.-GeO₂. The melting points, respectively, are 1033°± 5°C, 953°± 5°C, 1245°± 15°C, 1125°± 15°C, and 1280°± 15°C. Simple binary eutectic relations exist among the compounds. The eutectic temperature between 1:7 and GeO₂ is 1025°± 1h0°C at about 96.8 wt% GeO₂; the eutectic temperature between the 1:7 and 3:8 compounds is 935°± 10°C at about 90.9 wt% GeO₂; the eutectic temperature between the 3:8 and 1:1 compounds is 930°± 10 °C at about 89.8 wt% GeO₂. Liquidus data for compositions richer in lithia than the 1:1 compound are only approximate because of the difficulty of quenching them; the phase relations between the 1:1 and 3:2 and between the 3:2 and 2:l compounds, however, are found to be of the simple binary eutectic type. The glass–forming region was also determined. Melts allowed to cool in air crystallized. When, however, the melts were quenched, glasses containing as much as 8 wt% GeO₂ could be prepared in 5–g quantities. Both the refractive index–composition and density–composition curves for the glasses showed maxi–mums at about 6 to 8 wt% Li₂O.