Intraoperative 3-dimensional imaging of scaphoid fracture reduction and fixation.

INTRODUCTION: We examined the clinical benefit of two intraoperative three-dimensional imaging modalities for reduction and fixation of scaphoid fractures. HYPOTHESIS: Our hypothesis was that three dimensional imaging will aid in operative care in comparison with standard fluoroscopy. METHODS: In 25 consecutive patients treated for fractures, after satisfactory reduction and fixation was obtained with a single Kirschner wire using fluoroscopy, intraoperative three-dimensional visualization was performed. The quality of fracture reduction, wire position and extrusion of the wire were examined. RESULTS: In two of the 25 cases, after three-dimensional visualization, malreduction of the fracture was seen and the reduction revised. Artifact and the dependency on technologist performance, limited the use of these modalities to locate the wire accurately. DISCUSSION: Diagnosis of malreduction of a scaphoid fracture is possible with 3-dimensional modalities. Utilization of these systems is still limited by technical factors.

Proposed technique for evaluation of endotracheal tube fixation and comparison of four fixation methods.

BACKGROUND: The fixation of an endotracheal tube must be rapid in conditions involving numerous casualties, such as a chemical warfare (CW) situation. The tube also should be fixed and strong to prevent unplanned extubations. METHODS: We developed a technique for the evaluation of fixation methods. This technique was used to evaluate four methods. Three commercial fixators were compared with the fixation method used today in the Israeli Defense Forces (IDF) and commonly used in different out-of-hospital settings. The exercises were performed on adult intubation mannequins with and without CW protective gear. The fixations were timed, and their quality was evaluated by the participants and inspectors. RESULTS: The time score for the method used today in the IDF was significantly higher compared with the commercial fixation methods. The quality scores for the Thomas fixator and the IDF method were significantly higher than for the fixators by VBM and Rusch. The CW protective gear significantly prolonged the time but did not affect the quality of the fixation. CONCLUSIONS: With this technique, a good estimation of the time and quality of fixation can be achieved.

Poliovirus 2A protease induces apoptotic cell death.

A cell line was generated that expresses the poliovirus 2A protease in an inducible manner. Tightly controlled expression was achieved by utilizing the muristerone A-regulated expression system. Upon induction, cleavage of the eukaryotic translation initiation factor 4GI (eIF4GI) and eIF4GII is observed, with the latter being cleaved in a somewhat slower kinetics. eIF4G cleavage was accompanied by a severe inhibition of protein synthesis activity. Upon induction of the poliovirus 2A protease, the cells displayed fragmented nuclei, chromatin condensation, oligonucleosome-size DNA ladder, and positive TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining; hence, their death can be characterized as apoptosis. These results indicate that the expression of the 2A protease in mammalian cells is sufficient to induce apoptosis. We suggest that the poliovirus 2A protease induces apoptosis either by arresting cap-dependent translation of some cellular mRNAs that encode proteins required for cell viability, by preferential cap-independent translation of cellular mRNAs encoding apoptosis inducing proteins, or by cleaving other, yet unidentified cellular target proteins.

Evaluation of a novel protective gas mask during medical unit activity.

Evaluation of a battalion medical unit drill in a chemical warfare environment was carried out by comparing two respiratory protective devices: a new protective device (the Chemical Team Respirator) and the mask currently used in the Israel Defense Forces (the M-15). After a medical deployment drill conducted with 24 participants and 14 inspectors, comfort, communication, and various aspects of activity were evaluated by structured questionnaires. The new device, consisting of a hood, nose cup, and air blower system, was found to be preferable to the M-15 mask for physical and respiratory comfort, quality of visual field, and performance. The communication capabilities of the unit members, on the other hand, were severely limited by the hearing reduction caused by the hood of the new protective device. We conclude that the new device proved superior to the current mask by facilitating better performance of the team at the drill. Interference with hearing must be dealt with technically or bypassed by modifications in the unit's mode of communication.

Estrogen-receptor expression and function in thymocytes in relation to gender and age.

The expression of estrogen receptor (ER) in thymocytes was studied in young, middle-aged, and old (2, 12, and 24 months, respectively) female and male C57BL/6J mice. Western immunoblots prepared from the thymocytes of females of all age groups showed the presence of a 67-kD protein band, which has been associated with the apparent MW of denatured ER. Flow cytometry analysis of cells stained with a monoclonal anti-ER antibody (clone 13H2) disclosed ER expression in both females and males of all age groups. In vivo treatment with estradiol (E2) led to an increase in the specific activity of thymic creatine kinase (CK) in the female mice, whereas the male thymocytes responded with an increase in CK activity only on treatment with dihydrotestosterone (DHT). The data show no differences in ER expression between male and females, but the receptor appears not to be functional in males. Interestingly, when estradiol was applied to co-cultures of lymphoid-depleted fetal thymus (FT) explants and bone-marrow cells, or thymocytes, from young and old females, it resulted in increased cellularity of cultures containing cells of the young, and not those of the old. The proportion of CD4/CD8 phenotypes of the developing cells in these cultures was not affected by E2 treatment. These observations provide a new insight into ER expression and function in T-cell development in relation to gender and age.

Sleep quality in children with attention deficit hyperactivity disorder: an actigraphic study.

The aim of the present study was to compare the sleep of 12 children with attention deficit hyperactivity disorder (ADHD) with that of 12 normal controls. The children were examined in their natural environment, using continuous actigraphic monitoring over several consecutive nights, as well as undergoing subjective parental reports. It was hypothesized that children diagnosed with ADHD would suffer from reduced sleep quality than children without ADHD. This hypothesis was supported by the actigraphic measures, but not supported by the subjective parental reports. It was also found that the sleep quality of the two groups differed over the course of the night, which suggests a difference in sleep architecture. Various possible explanations for these findings, their implications regarding the relationship between sleep and ADHD, and the resulting treatment ramifications are discussed, and suggestions for further research are provided.

Regulation of human immunodeficiency virus Nef protein by phosphorylation.

Human immunodeficiency virus isolates express a Nef protein with either an alanine or a threonine at amino acid residue 15. The threonine residue is a site for phosphorylation by protein kinase C. Jurkat T cells constitutively expressing the alanine variant of Nef exhibit the ability to downregulate the induction of transcription factors NF-kB and AP-1. In contrast, Jurkat cells with the threonine variant of Nef are at least partially restored in their ability to recruit NF-kB and AP-1.

HIV-1 Nef protein inhibits the recruitment of AP-1 DNA-binding activity in human T-cells.

The human immunodeficiency virus type 1 long terminal repeat, HIV-1-LTR, contains binding sites for several cellular transcription factors which contribute to HIV-1 gene expression. Our previous studies on the function of the HIV-1-encoded Nef protein suggested that Nef may be an inhibitor HIV-1 transcription. To determine whether Nef affects the binding of cellular factors implicated in HIV-1 regulation, 32P-labeled oligonucleotides corresponding to the binding sites were incubated with nuclear extracts prepared from Nef-expressing T-cell lines that were not stimulated or were stimulated with T-cell mitogens. We found that Nef inhibited the recruitment of AP-1 DNA-binding activity in mitogen-stimulated human T-cells. Additionally, Nef expressing cells were transiently transfected with a plasmid in which HIV-1 AP-1 DNA recognition sequences were cloned downstream of the chloramphenicol acetyltransferase (CAT) gene. Mitogen-mediated transcriptional activation of the CAT gene in this construct was inhibited in Nef-expressing cells but not in control cells. These studies suggest that, by inhibiting AP-1 activation, Nef may play a role in regulating HIV-1 gene expression in infected T-cells.

Human immunodeficiency virus type 1 Nef protein inhibits NF-kappa B induction in human T cells.

Human immunodeficiency virus type 1 (HIV-1) can establish a persistent and latent infection in CD4+ T lymphocytes (W. C. Greene, N. Engl. J. Med. 324:308-317, 1991; S. M. Schnittman, M. C. Psallidopoulos, H. C. Lane, L. Thompson, M. Baseler, F. Massari, C. H. Fox, N. P. Salzman, and A. S. Fauci, Science 245:305-308, 1989). Production of HIV-1 from latently infected cells requires host cell activation by T-cell mitogens (T. Folks, D. M. Powell, M. M. Lightfoote, S. Benn, M. A. Martin, and A. S. Fauci, Science 231:600-602, 1986; D. Zagury, J. Bernard, R. Leonard, R. Cheynier, M. Feldman, P. S. Sarin, and R. C. Gallo, Science 231:850-853, 1986). This activation is mediated by the host transcription factor NF-kappa B [G. Nabel and D. Baltimore, Nature (London) 326:711-717, 1987]. We report here that the HIV-1-encoded Nef protein inhibits the induction of NF-kappa B DNA-binding activity by T-cell mitogens. However, Nef does not affect the DNA-binding activity of other transcription factors implicated in HIV-1 regulation, including SP-1, USF, URS, and NF-AT. Additionally, Nef inhibits the induction of HIV-1- and interleukin 2-directed gene expression, and the effect on HIV-1 transcription depends on an intact NF-kappa B-binding site. These results indicate that defective recruitment of NF-kappa B may underlie Nef's negative transcriptional effects on the HIV-1 and interleukin 2 promoters. Further evidence suggests that Nef inhibits NF-kappa B induction by interfering with a signal derived from the T-cell receptor complex.

The effect of defocusing the image on the perception of the temporal order of flashing lights.

The temporal interval between flashing lights that is required to perceive nonsimultaneity decreases as the refractive error increases from 0 to +2 diopters. The interval then remains constant with further increases to 3 and 4 diopters. The results are discussed in terms of the relative increase of transient to sustained visual channels and of the increase in apparent movement.

Expression of the type 1 human immunodeficiency virus Nef protein in T cells prevents antigen receptor-mediated induction of interleukin 2 mRNA.

Stable transformants of the Jurkat T-cell line have been obtained that express either of two distinct forms of the type 1 human immunodeficiency virus nef gene: the nef-1-encoded protein (Nef-1) contains alanine, glycine, and valine at positions 15, 29, and 33, respectively; the protein specified by nef-2 (Nef-2) has threonine, arginine, and alanine at the corresponding positions. When Jurkat cells or their Nef-2-expressing transformants are treated with phorbol 12-myristate 13-acetate (PMA) plus either phytohemagglutinin (PHA) or antibodies against CD3 epsilon, T-cell receptor beta chain, or CD2, there is a prompt increase in interleukin 2 (IL-2) mRNA and intracellular calcium and in the IL-2 receptor alpha chain on the cell surface. Although cells expressing Nef-1 also induce calcium mobilization and the production of IL-2 receptor alpha chain, the formation of IL-2 mRNA is blocked in response to these stimuli. Moreover, Nef-1-expressing cells transfected with a plasmid in which the IL-2 promoter is fused to the chloramphenicol acetyltransferase (CAT) gene fail to induce CAT following treatment with PMA and PHA. By contrast, the parental and Nef-2-containing cells induce CAT normally. Nef-1-expressing cells can produce IL-2 mRNA in response to a combination of PMA and ionomycin, although much less efficiently than the parental Jurkat cells or Nef-2-expressing cells. These findings, and others described herein, suggest that the virally encoded Nef protein interferes with a signal emanating from the T-cell receptor complex that induces IL-2 gene transcription.

Effect of extraneous targets on identification of color-coded targets.

Subjects matched the color of a vertical target line, presented in 1 of 10 colors, to a set of 10 colors. The target line was presented either in isolation or together with 5 additional colored lines. Neither mean reaction time nor the number of matching errors increased when the extraneous lines were present, and the types of color confusions did not change systematically.

Effect of luminance on the perception of temporal order of flashing lights.

The temporal interval between flashing lights required to perceive nonsimultaneity increases with decreasing luminance. This explanation appears to lie in the reported changes in the activity of the transient cells in the visual system with changes in luminance.

Performance and preference with various VDT phosphors.

Subjects searched for target letters and symbols in VDT displays produced with green, amber, yellow, red, blue, and white phosphors. The green was rated more highly than yellow, and blue was rated worst. There were no significant differences in search time, but there were significant differences in the number of errors made with different phosphors. Yellow produced the fewest errors and white the most. Speed and accuracy did not correlate with the preference ratings for the various phosphors.

Expression of the kil gene of the ColE1 plasmid in Escherichia coli Kilr mutants causes release of periplasmic enzymes and of colicin without cell death.

Expression of the kil gene of the ColE1 plasmid in certain classes of Escherichia coli mutants (Kilr) resistant to kil-caused cell death brought about release of periplasmic enzymes and of colicin. Phospholipase A was present but was not activated by kil expression in any of the mutants. This indicates that in these mutants the various effects of kil gene expression have become dissociated.

Age and disturbance of dark adaptation by extreme peripheral light.

The effects on dark adaptation of exposure to light presented only in the extreme periphery were significantly greater for observers over the age of 40 years. Increasing the exposure duration from 0.5 to 5 min significantly affected only the older observers.

Promoter and enhancer elements in the rearranged alpha chain gene of the human T cell receptor.

We cloned and compared the sequence of a rearranged human T cell receptor (TCR) V alpha J alpha gene and its germline counterparts. The only difference in the coding region sequence was confined to the joining region where three nucleotides, TTG, unaccountable by either V alpha or J alpha sequence, were present. By nuclease S1 mapping we identified the mRNA start of the alpha chain 70 nucleotides upstream from the initiator ATG. A 600 bp fragment containing the sequences upstream to the ATG drives the expression of the bacterial chloramphenicol acetyltransferase (CAT) gene. This promoter activity is T cell specific since it can be demonstrated in human T cells but not in B cells or HeLa cells. A 1.1 kb BamHI- HindIII fragment located 5' to the first exon of the C alpha gene was found to enhance transcription from either the heterologous SV40 promoter or the homologous TCR alpha chain promoter. This enhancement activity was independent of the location of the fragment with respect to CAT and was specific to lymphoid cells (either T or B cells) but cannot be demonstrated in HeLa cells.

[The Chernobyl accident. Evaluation of the doses absorbed by the thyroid gland in children of a mountain community from the measurement of I131 retained activity]. / Incidente di Chernobyl. Valutazione della dose assorbita dall tiroide nei bambini di una Comunità Montana a partire dalle misure di attività ritenuta di I131.

I131 thyroid uptake after the Chernobyl's accident was sampled in a Val Pellice school. Children were grouped according to sex, age and area of residence. The procedure used in collecting data and calculating the transformation coefficients from activity counts by computer simulation is analysed, as are the errors and sensitivity of the method. The activities were then converted into doses using an intake model. The dose levels identified are lower than the estimates based on the measurement of environmental matrices. Statistical analysis revealed certain subgroups with significantly different levels of absorption: particularly groups accustomed to a different diet or living in particular areas.