Image Quality Required for the Diagnosis of Skull Fractures Using Head CT: A Comparison of Conventional and Improved Reconstruction Kernels

BACKGROUND AND PURPOSE

Although skull fractures are generally assessed on bone images obtained by using head CT, the combined multikernel technique that enables evaluation of both brain and bone through a change in the window settings of an image set has been reported. The purpose of this retrospective study was to determine the image quality required for the accurate assessment of skull fractures by using head CT.

MATERIALS AND METHODS

A random sample of 50 patients (25 nonfracture and 25 simple nondisplaced skull fractures) was selected, and sets of conventional brain and bone images and improved combined multikernel images were reconstructed (4614 images). Three radiologists indicated their confidence levels regarding the presence of skull fractures by marking on a continuous scale for each image set. The mean area under the receiver operating characteristic curve was calculated for each kernel, and the statistical significance of differences was tested by using the Dorfman-Berbaum-Metz method.

RESULTS

Although a difference in the diagnostic performance of the 3 radiologists was suggested, the mean area under the curve value showed no significant differences among the 3 reconstruction kernels (P = .95 [bone versus combined]), P = .91 [bone versus brain]), and P = .88 [brain versus combined]). However, the quality of brain images was distinctly poorer than the quality of the other 2 images.

CONCLUSIONS

There was no significant difference in the diagnostic performance of brain, bone, and combined multikernel images for skull fractures. Skull fracture diagnosis is made possible by brain image assessments. Combined multikernel images offer the advantage of high-quality brain and bone images.

In utero gene therapy rescues microcephaly caused by Pqbp1-hypofunction in neural stem progenitor cells

Human mutations in PQBP1, a molecule involved in transcription and splicing, result in a reduced but architecturally normal brain. Examination of a conditional Pqbp1-knockout (cKO) mouse with microcephaly failed to reveal either abnormal centrosomes or mitotic spindles, increased neurogenesis from the neural stem progenitor cell (NSPC) pool or increased cell death in vivo. Instead, we observed an increase in the length of the cell cycle, particularly for the M phase in NSPCs. Corresponding to the developmental expression of Pqbp1, the stem cell pool in vivo was decreased at E10 and remained at a low level during neurogenesis (E15) in Pqbp1-cKO mice. The expression profiles of NSPCs derived from the cKO mouse revealed significant changes in gene groups that control the M phase, including anaphase-promoting complex genes, via aberrant transcription and RNA splicing. Exogenous Apc4, a hub protein in the network of affected genes, recovered the cell cycle, proliferation, and cell phenotypes of NSPCs caused by Pqbp1-cKO. These data reveal a mechanism of brain size control based on the simple reduction of the NSPC pool by cell cycle time elongation. Finally, we demonstrated that in utero gene therapy for Pqbp1-cKO mice by intraperitoneal injection of the PQBP1-AAV vector at E10 successfully rescued microcephaly with preserved cortical structures and improved behavioral abnormalities in Pqbp1-cKO mice, opening a new strategy for treating this intractable developmental disorder.

Endovascular management of multiple arterial aneurysms in Behcet's disease

We report a case of Behcet's disease complicated by four arterial aneurysms successfully treated by coil embolisation and stent placement. Percutaneous endovascular repair offers a safe alternative to surgical management of this serious condition.

Expression of vinexin alpha in the dorsal half of the eye and in the cardiac outflow tract and atrioventricular canal

Vinexin, a recently identified cytoskeletal protein, contains three SH3 domains and plays important roles in regulation of cytoskeletal organization and signal transduction. Using whole-mount in situ hybridization, we showed here that expression of vinexin alpha, the longer vinexin transcript, is strictly regulated, although the shorter transcript, vinexin beta, is expressed almost ubiquitously during embryonic development in mice. Expression of vinexin alpha was limited to within part of the eye and heart in 10.5 dpc embryos. Analysis of cryosections of 10.5 dpc embryos showed that vinexin alpha was expressed in a dorsal half of the retinal pigment epithelium and in the outflow tract and atrioventricular canal of the heart. Furthermore, we also found that vinexin alpha was expressed in the gonad and in a ventral part of the pons of 12.5 dpc embryos. These results indicated that the expression of vinexin alpha is strictly regulated in a temporally and spatially restricted manner.

Enhancement of bone ingrowth in a titanium fiber mesh implant by rhBMP-2 and hyaluronic acid

The present study was designed to evaluate the efficacy of high molecular weight hyaluronic acid (HA) used as a carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) adsorbed to a titanium fiber mesh implant (TFMI) in vivo. The quantity of HA in the TFMI rapidly decreased during the initial 3-day period after implantation. BMP particles were trapped by the meshwork of HA as observed by scanning electron microscopy (SEM). TFMIs containing LF-6, HA, rhBMP-2, or HA combined with rhBMP-2 were implanted on the cranium of rats. Analysis of digitized SEM images of samples obtained six weeks post-implantation was performed to determine the area occupied by new bone. The area fraction of Ca relative to that of the pores of TFMI in the HA group was larger than that in the Ti group (p<0.05). The area fraction of Ca in both the BMP and HA+BMP groups was larger than that in both the Ti and HA groups (p<0.01), and that in the HA+BMP group was larger than that in the BMP group (p<0.05). It is suggested that HA is not only an effective carrier of BMP, but also it may have a positive effect on the generation of new bone in the TFMI.

The biocompatibility and osteoconductive activity of a novel hydroxyapatite/collagen composite biomaterial, and its function as a carrier of rhBMP-2

A hydroxyapatite/type I collagen (HAp/Col) composite, in which the hydroxyapatite nanocrystals align along the collagen molecules, has been prepared. The biocompatibility, osteoconductive activity, and efficacy as a carrier of recombinant human bone morphogenetic proteins (rhBMPs) of this novel biomaterial were examined. The composite material was implanted in the backs of Wistar rats, and specimens were collected for histological observations until week 24. In a second experiment, other samples of the composite material (5 x 5 x 10 mm3) were drilled and immersed in a solution of rhBMP-2 (0, 200, 400 microg/mL), and subsequently grafted in radii and ulnae in beagle dogs. As a control, three unfilled holes were left in one radius and ulna. X-ray images were prepared, and specimens collected for histological observation at weeks 8 and 12. Histological findings of the composites grafted in rats showed that the surface of the material was eroded as a result of macrophage infiltration. X-ray images and histological findings for the composites implanted in dogs support the idea that HAp/ Col has a high osteoconductive activity and is able to induce bone-remodeling units. In cases where the implants are grafted at weight bearing sites, treatment with rhBMP-2 at a dose of 400 microg/mL may be useful to shorten the time needed until bone union has occurred.

Determination of a new thymidine phosphorylase inhibitor, TPI, in dog and rat plasma by reversed-phase ion-pair high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of a new thymidine phosphorylase inhibitor, TPI, in dog and rat plasma is described. TPI was isolated from biological samples by solid-phase extraction on Bond Elut PRS columns. Chromatographic separation was achieved on a C18 column using a mobile phase consisting of acetonitrile-10 mM acetate buffer (pH 4.3) including hexanesulfonate, with UV detection at 276 nm. This method has been validated across the range of 50-50000 ng/ml using a 0.1-ml plasma volume. The mean recoveries from spiked plasma were 93% for dog and 94% for rat, respectively. The accuracy, precision and specificity of the method were demonstrated to be acceptable, and it was applied to the toxicokinetic study of TPI in rats.

Diurnal changes in retinula cell sensitivities and receptive fields (two-dimensional angular sensitivity functions) in the apposition eyes of Ligia exotica (Crustacea, Isopoda)

The structural organization of the retinula cells in the eye of Ligia exotica changes diurnally. At night, the microvilli elongate, losing the regular and parallel alignment characteristic of the day condition. Crystalline cones and distal rhabdom tips are not pushed into each other during the day, but at night the rhabdoms protrude into the crystalline cones by up to 5 microm. Screening pigment granules in the retinula cells disperse during the night, but migrate radially towards the vicinity of the rhabdom during the day. No such displacements of the pigment granules of either distal or proximal screening pigment cells were observed. The sensitivity of the eye, monitored by electroretinogram (ERG) recordings, changes diurnally: values at midnight are, on average, 10 times those occurring during the day. However, intracellular recordings from single retinula cells (50 during the day and 50 at night) indicate that the difference between night and day sensitivities is only 2.5-fold. Two-dimensional angular sensitivity curves, indicative of a single unit's spatial sensitivity, had considerably less regular outlines at night than during the day. If based on the 50 % sensitivity level, day and night eyes possessed receptive fields of almost identical width (approximately 2 degrees), but if sensitivities below the 50 % limit were included, then receptive fields at night were significantly more extensive. We suggest that the morphological adaptations and diurnal changes in chromophore content seen in the apposition eye of L. exotica allow this animal to improve its photon capture at night while preserving at least some of the spatial resolving power characteristic of the light-adapted state. This would explain why this animal is capable of performing complex escape behaviours in the presence of predators both in bright and in very dim light.

Observation of nuclear excitation by electron transition in 197Au with synchrotron X rays and an avalanche photodiode

We have succeeded in observing nuclear excitation by electron transition (NEET) in 197Au by a new method. Monochromatic x-rays of synchrotron radiation were used to ionize the K shell of gold atoms in a target foil. The internal-conversion electrons emitted from excited nuclei were detected with a silicon avalanche photodiode. At a photon energy of 80.989 keV, the NEET probability in 197Au was determined to be (5.0+/-0.6)x10(-8) from a comparison of the event number per photon between NEET and the nuclear resonance at 77.351 keV.

Acceleration of Ca2+ ionophore-induced arachidonic acid liberation by thrombin without the proteolytic action toward the receptor in human platelets

We investigated the regulation of arachidonic acid liberation catalyzed by group-IV cytosolic phospholipase A2 (cPLA2) in human platelets upon stimulation with thrombin through interaction with protease-activated receptor-1 (PAR-1) or glycoprotein Ib. Leupeptin, a protease inhibitor, completely inhibited thrombin-induced arachidonic acid liberation and Ca2+ mobilization, with inhibition of its protease activity. However, preincubation with thrombin in the presence of leupeptin potentiated Ca2+ ionophore-induced arachidonic acid liberation. The preincubation did not affect the intracellular Ca2+ level or cPLA2 activity in response to ionomycin. Human leukocyte elastase, which cleaves glycoprotein Ib, did not inhibit the enhancement of arachidonic acid liberation by thrombin in the presence of leupeptin. However, the effect of thrombin with leupeptin was abolished by a peptide corresponding to residues 54-65 of hirudin (hirudin peptide), which impairs the binding of thrombin to PAR-1. Furthermore, Phe-Pro-Arg chloromethyl ketone (PPACK)-thrombin, which binds to platelets but has no protease activity, also enhanced Ca2+ ionophore-induced arachidonic acid liberation. In contrast, trypsin with leupeptin did not mimic the effect of thrombin with leupeptin, and furthermore trypsin-induced arachidonic acid liberation was insensitive to hirudin peptide. On the basis of the present results, we suggest that thrombin may accelerate cPLA2-catalyzed arachidonic acid liberation through non-proteolytic action toward PAR-1 but not toward glycoprotein Ib in co-operation with the proteolytic action leading to Ca2+ mobilization.

Vinexin: a novel vinculin-binding protein with multiple SH3 domains enhances actin cytoskeletal organization

Using the yeast two-hybrid system and an in vitro binding assay, we have identified a novel protein termed vinexin as a vinculin-binding protein. By Northern blotting, we identified two types of vinexin mRNA that were 3 and 2 kb in length. Screening for full-length cDNA clones and sequencing indicated that the two mRNA encode 82- and 37-kD polypeptides termed vinexin alpha and beta, respectively. Both forms of vinexin share a common carboxyl-terminal sequence containing three SH3 domains. The larger vinexin alpha contains an additional amino-terminal sequence. The interaction between vinexin and vinculin was mediated by two SH3 domains of vinexin and the proline-rich region of vinculin. When expressed, vinexin alpha and beta localized to focal adhesions in NIH 3T3 fibroblasts, and to cell-cell junctions in epithelial LLC-PK1 cells. Furthermore, expression of vinexin increased focal adhesion size. Vinexin alpha also promoted upregulation of actin stress fiber formation. In addition, cell lines stably expressing vinexin beta showed enhanced cell spreading on fibronectin. These data identify vinexin as a novel focal adhesion and cell- cell adhesion protein that binds via SH3 domains to the hinge region of vinculin, which can enhance actin cytoskeletal organization and cell spreading.

Inhibitory effect of the leaf extract of Ginkgo biloba L. on oxidative stress-induced platelet aggregation

The effect of the leaf extract of Ginkgo biloba L. on platelet aggregation induced by oxidative stress was studied. The extract caused a dose-dependent inhibition of platelet aggregation stimulated with tert-butyl hydroperoxide (t-BHP) and Fe2+. Similar inhibitory activity was observed when platelets were exposed to H2O2 and Fe2+. Synergistic aggregation induced by a combination of t-BHP and Fe2+ or H2O2 and Fe2+ in association with suboptimal concentration of collagen or U46619, was prevented by the extract. However, the extract failed to inhibit aggregation in response to collagen, thrombin or U46619. Ginkgolides A, B and C inhibited platelet-activating factor-induced aggregation, but not oxidant-induced aggregation. These data suggest that the suppressive effect of the extract is specific on platelet aggregation stimulated by oxidative stress, and that this effect is involved in the mechanism related to its protective effect upon cerebral or myocardial injuries.

Inhibition of anchorage-independent growth of tumor cells by IT-62-B, a new anthracycline

IT-62-B, a new anthracycline isolated from fermentation broths of Streptomyces sp. IT-62, reversed certain tumor cell phenotypes in vitro including some of human origin. The observed normal phenotypes were anchorage dependence of cell growth, flattened cell morphology and restoration of actin stress fibers. The extent of the anchorage dependence of cell growth induced by IT-62-B was generally greater than that by doxorubicin or pirarubicin. The cell-flattening effect of IT-62-B on cells of T24 (human bladder), but not on C-33A (human cervix), accompanied inhibition of fos gene expression. T24 cells, once flattened by IT-62-B, retained their flat morphology even in drug-free, fresh medium and eventually died in several days. IT-62-B, unlike doxorubicin, only slightly inhibited the topoisomerase II reaction in vitro and DNA synthesis in isolated cell nuclei.

A new anthracycline antibiotic, IT-62-B, converts the morphology of ras-transformed cells back to normal: taxonomy, fermentation, isolation, structure elucidation and biological characterization

A new antibiotic, IT-62-B was isolated from the culture broth of Streptomyces sp. IT-62 by extraction with acetone and then with ethyl acetate, followed by conventional column chromatography using silica gel, Sephadex LH-20 and silica ODS. Its structure (C39H47NO15, MW 769) was determined by 1H, 13C NMR, MS, IR and UV spectrometric techniques to be a new member of the baumycin-group anthracyclines. It showed moderate activity against Gram-positive bacteria and had antitumor activity against various tumor cell lines. Further, antibiotic IT-62-B converted the morphology of ras-transformed NIH3T3 cells and T-cells back to normal at concentrations inhibiting cell growth by 30% or more.

Histological evidence of natural killer cell aggregation against malignant melanoma induced by adoptive immunotherapy with lymphokine-activated killer cells

Adoptive immunotherapy with lymphokine-activated killer (LAK) cells and systemic administration of recombinant Interleukin-2 (RIL-2) was carried out in a case of malignant melanoma with lung metastases. Histological specimens from the lung showed a metastatic melanoma heavily invaded by atypical lymphoid cells with convoluted nuclei of varying size. Immunohistochemistry revealed that these cells had the characteristic exclusively of natural killer cell (Leu-7+). Nodules of these cells mimicked the appearance of non-Hodgkin's lymphoma of pleomorphic type. Molecular cytogenetic analysis, however, showed the absence of rearranged bands for the T-cell receptor beta-chain gene, indicating the absence of T-cell clones. At autopsy, 1 month after the LAK therapy, the heavy invasion of convoluted cells had disappeared. These findings clearly indicate that the LAK cell plus RIL-2 therapy induced Leu-7+ lymphoid cells, phenotypically suggestive of natural killer cell aggregation in the tumours.

[Transfer of ofloxacin into suction blister fluid after its oral administration]

After oral administration of 300 mg of ofloxacin (OFLX), the concentration of OFLX in serum peaked at 2 hours and reached 2.88 +/- 0.62 micrograms/ml (mean +/- S.D.). In the fluid of dermal blisters produced by suction, the peak value was 1.74 +/- 0.88 micrograms/ml at 4 hours. Pharmacokinetically, Cmax (maximum concentration), Tmax (time of maximum concentration), Ka (absorption rate constant) and AUC0-8hrs. (area under the concentration-time curve) were calculated as 2.65 micrograms/ml, 2.07 hours, 0.79 hr-1 and 14.5 micrograms.hr/ml in serum, and 1.59 micrograms/ml, 4.49 hours, 0.27 hr-1 and 10.1 micrograms.hr/ml, respectively. Therapeutic AUC (area under the curve above minimum effective concentration) were also calculated as 13.3 micrograms.hr/ml (0.14-12.4 hours) in serum, and 11.5 micrograms.hr/ml (0.42-17.3 hours).