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121.
VS Seybold I Grkovic AL Portbury YQ Ding R Shigemoto N Mizuno JB Furness BR Southwell 《Canadian Metallurgical Quarterly》1997,381(4):439-448
Exposure to the thiolamine radioprotector N-(2-mercaptoethyl)-1,3-propanediamine (WR-1065) induced apoptosis in the mouse TB8.3 hybridoma after a 60-min (LD50 = 4.5 mM) or during a 20-h (LD50 = 0.15 mM) exposure. In contrast, a 20-h exposure to 17 mM L-cysteine or 10 mM cysteamine was required to induce 50% apoptosis within 20 h. Apoptosis was not induced by either a 60-min or 20-h exposure to 10 mM of the thiazolidine prodrugs ribose-cysteine (RibCys) or ribose-cysteamine (RibCyst). Thiolamine-induced apoptosis appeared to be a p53-independent process since it was induced by WR-1065 exposure in human HL60 cells. Exposure to WR-1065 (4 mM for 15 min) or cysteine (10 mM for 60 min) before and during irradiation protected cells against the induction of both DNA double-strand breaks and apoptosis, while exposure to RibCys (10 mM for 3 h) did not. Treatment with either WR-1065, cysteine, RibCys or RibCyst for 60 min beginning 60 min after irradiation did not affect the level of radiation-induced apoptosis. In contrast, treatment with either cysteine, cysteamine or RibCys for 20 h beginning 60 min after irradiation enhanced radiation-induced apoptosis. Similar experiments could not be conducted with WR-1065 because of its extreme toxicity. Our results indicate that thiolamine enhancement of radiation-induced apoptosis is not involved in their previously reported capacity to reduce radiation-induced mutations. 相似文献
122.
123.
LI Voorhees JB Ryan RL Hopping MS Berman BN Brin W Levinson 《Canadian Metallurgical Quarterly》1997,68(7):435-447
BACKGROUND: Optometry has experienced a dramatic upward shift in the percentage of women entering the profession during the past 20 years. Our survey assessed the mechanisms for sustaining balance in professional and personal roles used by women optometrists and how these mechanisms may differ from those of their male colleagues. METHODS: A survey questionnaire was mailed to a large nationwide random sample of optometrists, composed of equal numbers of men and women. RESULTS: Data were analyzed from 353 men and 358 women; margin of error was +4%. Most of the respondents indicated they derived personal satisfaction from their career. A majority of both groups did not indicate that lack of time for their career was a source of frustration. However, significantly more women than men indicated some frustration in pursuing those activities that lead to career advancement. There were significant differences in response patterns of men and women about the effect of family, child care, and household work on their careers. CONCLUSIONS: Both men and women optometrists are satisfied with their careers and neither group feels compelled to choose between career and family. Optometrists do not fit into one pattern, but instead make individualized career choices on the basis of needs. 相似文献
124.
Phylogenetic relationships were determined for 76 partial P-element sequences from 14 species of the melanogaster species group within the Drosophila subgenus Sophophora. These results are examined in the context of the phylogeny of the species from which the sequences were isolated. Sequences from the P-element family fall into distinct subfamilies, or clades, which are often characteristic for particular species subgroups. When examined locally among closely related species, the evolution of P elements is characterized by vertical transmission, whereby the P-element phylogeny traces the species phylogeny. On a broader scale, however, the P-element phylogeny is not congruent with the species phylogeny. One feature of P-element evolution in the melanogaster group is the presence of more than one P-element subfamily, differing by as much as 36%, in the genomes of some species. Thus, P elements from several individual species are not monophyletic, and a likely explanation for the incongruence between P-element and species phylogenies is provided by the comparison of paralogous sequences. In certain instances, horizontal transfer seems to be a valid alternative explanation for lack of congruence between species and P-element phylogenies. The canonical P-element subfamily, which represents the active, autonomous transposable element, is restricted to D. melanogaster. Thus, its origin clearly lies outside of the melanogaster species group, consistent with the earlier conclusion of recent horizontal transfer. 相似文献
125.
F Lerang B Moum P Mowinckel JB Haug E Ragnhildstveit T Berge A Bj?rneklett 《Canadian Metallurgical Quarterly》1998,33(4):364-369
The financial burden for the evaluation of patients for acoustic neuroma in an otolaryngology practice is substantial. Patients with sudden sensorineural hearing loss represent a portion of that population seen with unilateral, asymmetric auditory symptoms who require investigation for acoustic neuroma. For these patients, gadolinium-enhanced magnetic resonance imaging is the diagnostic gold standard. Auditory brain stem response testing has been used in the past as a screening test for acoustic neuroma, but its apparent sensitivity has fallen as the ability to image smaller acoustic neuromas has improved. Fast spin echo magnetic resonance imaging techniques without gadolinium have been shown to be as effective in the detection of acoustic neuroma as contrast-enhanced magnetic resonance imaging. Limited nonenhanced fast spin echo magnetic resonance imaging now provides an inexpensive alternative for high-resolution imaging of the internal auditory canal and cerebellopontine angle. Fast spin echo magnetic resonance imaging can now be done at a cost approximating auditory brain stem response testing while providing the anatomic information of contrast-enhanced magnetic resonance imaging. Cost analysis was done in the cases of 58 patients with sudden sensorineural hearing loss by comparing the costs for routine workup and screening of acoustic neuroma with the cost of fast spin echo magnetic resonance imaging with the use of screening protocols based on literature review. The potential cost savings of evaluating patients with sudden sensorineural hearing loss with fast spin echo magnetic resonance imaging for acoustic neuroma was substantial, with a 54% reduction in screening costs. In an era of medical economic scrutiny, fast spin echo magnetic resonance imaging has become the most cost-effective method to screen suspected cases of acoustic tumors at our institution by improving existing technology while reducing the cost of providing that technology and eliminating charges for impedance audiometry, auditory brain stem response testing, and contrast-enhanced magnetic resonance imaging. 相似文献
126.
A Kumar JB Angel MP Daftarian K Parato WD Cameron L Filion F Diaz-Mitoma 《Canadian Metallurgical Quarterly》1998,114(1):78-86
The present study determines the proportions of unmyelinated cutaneous axons at the dermal-epidermal junction in glabrous skin and of myelinated and unmyelinated axons in the sural and medial plantar nerves that immunostain for subunits of the ionotropic glutamate receptors. Approximately 20% of the unmyelinated cutaneous axon profiles at the dermal-epidermal junction immunostain for either N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), or kainate receptor subunits. These findings are consistent with previous observations that NMDA and non-NMDA antagonists ameliorate nociceptive behaviors that result from noxious peripheral stimulation. In the sural nerve, where the large majority of myelinated fibers are sensory, approximately half of the myelinated axon profiles immunostain for the NMDA receptor 1 (R1) subunit, 28% immunostain for the glutamate receptor 1 (GluR1) AMPA subunit, and 11% for the GluR5,6,7 kainate subunits. Even higher proportions immunostain for these receptors in the medial plantar nerve, a mixed sensory and motor nerve. In the sural nerve, 20% of the unmyelinated axon profiles immunostain for NMDAR1 and only 7% label for GluR1 or GluR5,6,7. Because the sural nerve innervates hairy skin, these data suggest that glutamate will activate a higher proportion of unmyelinated axons in glabrous skin than in hairy skin. Measurements of fiber diameters indicate that all sizes of myelinated axon profiles, including Adelta and Abeta, are positively labeled for the ionotropic receptors. The presence of glutamate receptors on large-diameter myelinated axons suggests that these mechanosensitive receptors, presumably transducing touch and pressure, may also respond to local glutamate and thus be chemosensitive. 相似文献
127.
SR Hedges DA Sibley MS Mayo EW Hook MW Russell 《Canadian Metallurgical Quarterly》1998,178(3):742-751
The levels of interleukin (IL)-1, IL-6, IL-8, IL-10, and transforming growth factor-beta in sera and genital tract secretions from women with gonococcal cervicitis and other genital infections were examined. Cytokines were not elevated in genital secretions from gonococcus-infected compared with uninfected patients. The level of serum IL-6 was higher in gonococcus-infected than in uninfected patients at recruitment. Serum, but not local, IL-1 and IL-6 levels were elevated in patients concomitantly infected with Trichomonas vaginalis or Chlamydia trachomatis in addition to Neisseria gonorrhoeae compared with levels in patients infected with any single organism. Concomitant infection altered neither the total immunoglobulin concentrations nor the levels of antigonococcal antibodies in serum or local secretions. The results suggest that N. gonorrhoeae induces only a limited cytokine and antibody response during uncomplicated cervical infections; however, the presence of other sexually transmitted disease-causing organisms can alter the systemic cytokine but not the antigonococcal antibody levels. 相似文献
128.
OBJECTIVE: To assess the prevalence, clinical manifestations, associated genital infections, and HLA associations of reactive arthritis (ReA) among patients attending an urban sexually transmitted diseases (STD) clinic. METHODS: Using a standardized questionnaire, 271 consecutive adults, primarily black, with possible or proven Chlamydia trachomatis genital infection were screened for symptoms of ReA. A followup questionnaire was administered 6 weeks later by mail. Patients who reported at least 1 symptom were evaluated by a rheumatologist. HLA-B typing was performed on patients with objective ReA features. RESULTS: Nine of 217 patients (4.1%) with genital infection/inflammation had objective ReA features. Chlamydial or nongonococcal STD syndromes were diagnosed in 8 of these 9 patients (88%). Genital infection/inflammation was asymptomatic in 78% of patients with ReA features. HLA-B27 or other B7-cross-reactive group antigens were not associated with the occurrence of ReA. CONCLUSION: Nongonococcal genital infections, often asymptomatic, can trigger a relatively mild ReA in a larger number of exposed patients than previously thought, irrespective of the individual's HLA status. 相似文献
129.
The multiple chemical sensitivity syndrome (MCS) is a novel constellation of symptoms in environmental medicine that has been extensively described and commented on in the USA. The main features of this syndrome are: multiple symptoms in different organ systems triggered by a variety of chemical substances, with relapses and exacerbations under certain precipitating circumstances at very low levels which do not cause any reactions in the population at large. There are no lab markers or specific investigative findings. This paper describes the historical development of the term MCS, its diagnostic criteria and pathophysiological aspects using 10 patient histories from our hospital. 相似文献
130.
The effects of heparin and dextran sulfate 8,000 on two isoforms of the sarco/endoplasmic reticulum Ca(2+)-ATPase of different animal tissues and on the corn root H(+)-ATPase were examined. In the absence of sulfated polysaccharides the pH profile's of the three transport ATPases were quite different, but after the addition of heparin or dextran sulfate 8,000 the pH profiles of the three enzymes became similar, all showed maximal activity at pH 7.0. Potassium and sodium antagonized the effects of sulfated polysaccharides on the three transport ATPases, but the antagonism was considerably reduced at acidic pH values. 相似文献