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21.
Ascorbic acid and glutathione (GSH) are antioxidants and free radical scavengers that provide the first line of defense against oxidative damage in the CNS. Using HPLC with electrochemical detection, we determined tissue contents of these antioxidants in brain and spinal cord in species with varying abilities to tolerate anoxia, including anoxia-tolerant pond and box turtles, moderately tolerant garter snakes, anoxia-intolerant clawed frogs (Xenopus laevis), and intolerant Long-Evans hooded rats. These data were compared with ascorbate and GSH levels in selected regions of guinea pig CNS, human cortex, and values from the literature. Ascorbate levels in turtles were typically 100% higher than those in rat. Cortex, olfactory bulb, and dorsal ventricular ridge had the highest content in turtle, 5-6 mumol g-1 of tissue wet weight, which was twice that in rat cortex (2.82 +/- 0.05 mumol g-1) and threefold greater than in guinea pig cortex (1.71 +/- 0.03 mumol g-1). Regionally distinct levels (2-4 mumol g-1) were found in turtle cerebellum, optic lobe, brainstem, and spinal cord, with a decreasing anterior-to-posterior gradient. Ascorbate was lowest in white matter (optic nerve) in each species. Snake cortex and brainstem had significantly higher ascorbate levels than in rat or guinea pig, although other regions had comparable or lower levels. Frog ascorbate was generally in an intermediate range between that in rat and guinea pig. In contrast to ascorbate, GSH levels in anoxia-tolerant turtles, 2-3 mumol g-1 of tissue wet weight, were similar to those in mammalian or amphibian brain, with no consistent pattern associated with anoxia tolerance. GSH levels in pond turtle CNS were significantly higher (by 10-20%) than in rat for several regions but were generally lower than in guinea pig or frog. GSH in box turtle and snake CNS were the same or lower than in rat or guinea pig. The distribution GSH in the CNS also had a decreasing anterior-to-posterior gradient but with less variability than ascorbate: levels were similar in optic nerve, brainstem, and spinal cord. The paradoxically high levels of ascorbate in turtle brain, which has a lower rate of oxidative metabolism than mammalian, suggest that ascorbate is an essential cerebral antioxidant. High levels may have evolved to protect cells from oxidative damage when aerobic metabolism resumes after a hypoxic dive. 相似文献
22.
H Komuro MB Valentine ST Rowe VJ Kidd S Makino GM Brodeur SL Cohn AT Look 《Canadian Metallurgical Quarterly》1998,33(11):1695-1698
Artificial illumination is an important factor in the management of layers. In this study, a new monochromatic light system was developed for egg layers. Prelaying pullets (Lohmann) were marked and housed in nine light and temperature control rooms (15 battery cages, 3 hens per cage; n = 45), divided into three light treatments: 0.1 and 0.01 W/m2 light intensity using light emitting diode (LED) lamps and 0.1 W/m2 using mini-fluorescent bulbs (PL) (control). In each of the LED rooms, three wavelengths were tested: 560 (n = 9), 660 (n = 9), 880 (n = 6), and 660 intermitted lighting (15 min light 45 min dark, 660IN) (n = 9). Birds were exposed to 12 h light and 12 h of darkness using PL lamps. At 21 wk of age, the light period was increased to 12.75 h by using 5.5 h of LED lamps and 7.25 of PL light source for Groups 1 and 2, the third group received 12.75 h of PL light. Until 28 wk of age, light hours increased by 0.5 h/w using LED light for Groups 1 and 2 and PL source for the third group, reaching 16 h of light at 28 wk of age. Egg production and feed consumption were recorded daily; egg components were recorded weekly for 10 mo. A significant reduction in egg production was observed in all 880nm groups; no differences in egg production and quality were found in the other groups. Feed consumption was significantly lower by 7% in all 0.01 W/m2 groups. We suggest that an important reduction in rearing costs of laying hens may be obtained by using this system. 相似文献
23.
JH Noseworthy P O'Brien BJ Erickson D Lee D Sneve GC Ebers GP Rice A Auty WJ Hader A Kirk P Duquette J Carter G Francis L Metz E Shuster 《Canadian Metallurgical Quarterly》1998,51(5):1342-1352
OBJECTIVE: To determine whether sulfasalazine is better than placebo in slowing disability progression in MS. METHODS: In this randomized, double-blind, placebo-controlled phase III trial, 199 patients with active relapsing-remitting (n = 151) or progressive (n = 48) MS were evaluated at 3-month intervals for a minimum of 3 years (94% completed 3 years of follow-up; mean follow-up, 3.7 years). MRI studies were performed at 6-month intervals on a subset of 89 patients. RESULTS: Sulfasalazine failed to slow or prevent disability progression as measured by the primary outcome (confirmed worsening of the Expanded Disability Status Scale [EDSS] score by at least 1.0 point on two consecutive 3-month visits). Sulfasalazine influenced favorably a number of secondary outcomes during the first 18 months of the trial (e.g., annualized relapse rate, proportion of relapse-free patients; progressive subgroup only: rate of EDSS progression at 1 and 2 years, median time to EDSS progression) but these positive findings were not sustained into the second half of the trial. CONCLUSIONS: Sulfasalazine does not prevent EDSS score progression in the subset of MS patients studied by this protocol. Treatments may improve relapse-related outcomes in MS, at least temporarily, without providing sustained slowing of EDSS progression. Phase III MS trials should be of sufficient length to determine a meaningful impact on disease course. 相似文献
24.
M Tristam AS Alaamer JS Fleming VJ Lewington MA Zivanovic 《Canadian Metallurgical Quarterly》1996,37(6):1058-1063
In the treatment of neural crest tumors, such as pheochromocytoma, with[131I]MIBG, bone marrow toxicity limits the amount of administered activity and, thus, a therapeutically useful tumor dose. METHODS: We calculated tumor doses in a series of diagnostic studies with [123I]MIBG using accurate quantification of SPECT and planar scintigraphy. By extrapolating diagnostic results to therapeutic activities of [131I]MIBG, we could compare the results with whole-body doses from a series of therapies. RESULTS: The tumor dose was DT = 2.2 mGy MBq(-1) (median value of 27 measurements, range 0.04 < or = DT < or = 20 mGy MBq(-1) and the whole-body dose in a series of 16 patients undergoing 50 therapies was DWB = 0.12 +/- 0.04 mGy MBq(-1) (mean +/- s.d.). The therapeutic ratio varied between 130 to below 10 in some patients. CONCLUSION: The results were compared with published data. We found clearly skewed distribution of tumor doses, with a majority of tumors receiving only a few mGy per MBq administered activity. In some patients, however, doses did reach 20 mGy MBq(-1). 相似文献
25.
D Matecka RB Rothman L Radesca BR de Costa CM Dersch JS Partilla A Pert JR Glowa FH Wojnicki KC Rice 《Canadian Metallurgical Quarterly》1996,39(24):4704-4716
The design, synthesis, and biological evaluation of compounds related to the dopamine (DA) uptake inhibitors: 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine (1) and 1-[2-[bis-(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine (2) (GBR 12395 and GBR 12909, respectively), directed toward the development and identification of new ligands interacting with high potency and selectivity at the dopamine transporter (DAT) is reported. The substitution of the piperazine ring in the GBR structure with other diamine moieties resulted in the retention of the high affinity of new ligands for the DAT. Some of the modified GBR analogs (e.g. 8, 10, (-)-49, or (-)-50) displayed substantially higher selectivity (4736- to 693-fold) for the dopamine (DA) versus the serotonin (5HT) reuptake site than the parent compounds. The bis(p-fluoro) substitution in the (diphenylmethoxy)ethyl fragment slightly increased the affinity of the ligands at the DA reuptake site but reduced their selectivity at this site (e.g. 9 and 8, 11 and 10, or 17 and 16, respectively). Congeners, such as the series of monosubstituted and symmetrically disubstituted piperazines and trans-2,5-dimethylpiperazines, which lack the (diphenylmethoxy)ethyl substituent lost the affinity for the DAT yet exhibited very high potency for binding to the sigma receptors (e.g.28). The chiral pyrrolidine derivatives of 1, (-)-49, and (+)-49, exhibited an enantioselectivity ratio of 181 and 146 for the inhibition of DA reuptake and binding to the DAT, respectively. 相似文献
26.
Influenza caused low levels of mortality and morbidity in England and Wales in the 1997/98 season. Influenza viruses of the H3N2 and H1N1 subtypes were isolated in small numbers from community and hospital patients in November and December. Their numbers subsequently increased to peak in February, H1N1 a week or two before H3N2. Most of the H1N1 isolates were similar to the A/Bayern/7/95-like virus, included in the vaccine recommended for 1997-98, whereas most H3N2 isolates were A/Sydney/5/97-like, a virus not covered by the season's vaccine but recommended for 1998/99. Consultation rates in general practice for influenza-like illnesses remained low until early February, when a small increase coincided with the increase in laboratory confirmed influenza. Fewer deaths directly attributed to influenza were registered during the surveillance period than in recent years. Localised outbreaks occurred in schools and nursing homes towards the end of the winter. 相似文献
27.
VJ Paul Y Seo KW Cho JR Rho J Shin PR Bergquist 《Canadian Metallurgical Quarterly》1997,60(11):1115-1120
Ten sesquiterpenoids, including seven new ones, have been isolated from an undescribed sponge of the genus Dysidea. Compounds 1-8 are sesquiterpenoids of the drimane class, while 9 and 10 are 12-norsesquiterpenoids of the same structural class. The structures of novel compounds have been determined by combined spectroscopic methods. These compounds exhibited moderate antimicrobial and enzyme inhibitory (Na+/K(+)-ATPase and PLA2) activities. 相似文献
28.
Separation of sterol esters from wax esters in the lipids of vernix caseosa and adult human skin surface was accomplished
by column chromatography on MgO. The fatty acids of the sterol esters and wax esters of both samples were separated into saturates
and monoenes, and examined in detail by gas liquid chromatography (GLC). The saturated fatty acids of the wax esters of vernix
caseosa and of adult human skin surface were remarkably similar. They ranged in chain length from at least C11 to C30, six skeletal types being present: straight even, straight odd, iso, anteiso, other monomethyl branched and dimethyl branched.
A large number of patterns of monoenes were observed, each pattern consisting of desaturation of a specific chain at Δ6 or
Δ9 plus its extension or degradation products. The mole per cent of the total Δ6 and Δ9 patterns of wax ester fatty acid monoenes
of vernix caseosa were 87% and 12%, respectively, and 98% and 1%, respectively, for adult human skin surface lipid. The sterol
ester fatty acids of vernix caseosa were much different from those of adult human skin surface: vernix caseosa saturates were
largely branched and of lengths greater than C18, whereas the saturates of adult human surface lipid resembled the wax ester fatty acids. Of the vernix caseosa monoene patterns,
the mole per cent was 30% Δ6 and 70% Δ9, whereas of the adult human skin surface sterol ester fatty acids 89% were Δ6 and
11% Δ9. Chain extension was particularly pronounced in the sterol ester fatty acid monoenes of vernix caseosa amounting to
7–8 C2 units in some cases. The fatty acids of the sterol esters of both vernix caseosa and adult human skin surface appear to be
derived from the sebaceous gland and from the keratinizing epidermis, but those of the wax esters are from the sebaceous glands
only. 相似文献
29.
M. D. Wilding E. E. Rice K. F. Mattil 《Journal of the American Oil Chemists' Society》1963,40(2):55-57
On the basis of the chemical, physical, and biological criteria used, all of which have been shown to be sensitive indicators
of heat damage to oils, it must be concluded that the overall nutritional quality of an oil is not adversely affected by alkali
refining, adsorptive decolorizing, or deodorization; that higher temperatures of deodorization (238C) produce oils nutritionally
equivalent to those deodorized at lower temperatures (160C); and that the normal processes used in manufacturing edible oils
improve the resistance of these oils to heat damage.
Presented at the 6th Congress of the International Society for Fat Research, London, 1962. 相似文献
30.
This paper is a critical review and summary of the analytical procedures currently used by operating water utilities to control ozone treatment processes, considering disinfection as well as the many oxidative applications of ozone in water treatment applications. The role of common interferences in the various methods is described.
In operating U S., Canadian, European, and Japanese water treatment plants currently employing ozone as a primary disinfectant, ozone nearly always is followed by the addition of small quantities of chlorine, chlorine dioxide, or chloramine to provide the residual in the distribution system and to act as a secondary disinfectant. Clearly, the analytical procedures used must distinguish between the various species. This review critically presents these various factors and their implication with respect to “true values” of ozone determined under widely varying conditions. 相似文献