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21.
F Deák á Horváth á Kiss Z Seres A Galonsky CK Gelbke H Hama L Heilbronn D Krofcheck WG Lynch DW Sackett HR Schelin MB Tsang J Kasagi T Murakami 《Canadian Metallurgical Quarterly》1995,52(1):219-227
An extruding wire knife was used to give adult male CFHB rats a minimally traumatic unilateral mechanical lesion of the medial forebrain bundle. In addition, some rats received bilateral intrastriatal injections of one of three fluorescent retrograde tracers either eight days before or eight days after the lesion. Injections made after the lesion revealed that about half of the animals had complete lesions of the nigrostriatal tract, while the other half were incompletely lesioned, the mean proportion of non-axotomized neurons being 23%. Over the 10 weeks following the lesions, the number of tyrosine hydroxylase-immunoreactive cells in the lesioned substantia nigra fell linearly, reaching a mean of 29% of that of the control substantia nigra. In the animals which were completely lesioned, neuronal survival at 10 weeks varied between 6 and 12%. That the disappearance of tyrosine hydroxylase-immunoreactive neurons was due to cell death rather than the loss of tyrosine hydroxylase itself was confirmed by labelling the cells with Fluoro Gold before axotomy; the tracer was seen in survival neurons, microglia and in a few involuted neurons which continued to be tyrosine hydroxylase-immunoreactive. This percentage of neurons surviving axotomy corresponds to the proportion of substantia nigra neurons which project to the contralateral striatum, and these neurons were in the region of the substantia nigra from which the contralateral projection originated. It is concluded that following mechanical transection of the nigrostriatal tract, all truly axotomized substantia nigra neurons die over a period of about 10 weeks. 相似文献
22.
RE Droleskey PJ Holman KA Waldrup DE Corrier GG Wagner 《Canadian Metallurgical Quarterly》1993,79(3):424-434
Babesia odocoilei continuously cultured in white-tailed deer (Odocoileus virginianus) erythrocytes was examined by transmission and scanning electron microscopy. Merozoites, trophozoites, intermediate-stage forms, and dividing forms were observed. Merozoites possessed a single nucleus, inner membrane complex, rhoptries, free ribosomes, rough endoplasmic reticulum, and single membrane-bound vesicles. Trophozoites lacked an inner membrane complex and rhoptries. Intermediate stages were characterized by distinct segments of inner membrane complex. Dividing forms ranged from cells with an elongated nucleus to mature daughter cells joined by a ringlike structure. Babesia odocoilei was characterized by its close proximity to the erythrocyte membrane, membranous structures resembling feeding organelles, and reproduction via a method resembling budding sensu stricto. 相似文献
23.
Investigated the process of deciding whether or not to apply for jobs, using the verbal protocol analysis (VPA) technique. Verbal reports provided by participants as they evaluated job postings and decided whether or not to interview for jobs were analyzed to assess what information was heeded, the impact of incomplete or unusual information, and the role of inferences regarding job characteristics and probability of hire. Results indicated that location and compensation received the most attention and that participants also responded to the amount of information provided. In addition, participants made inferences about unobserved characteristics and probability of hire, although the latter played little role in the decision to interview. The study also provided support for the usefulness of VPA by demonstrating that neither the verbal protocol process nor the use of prompts significantly influenced participants' decisions (as compared with the decisions of control groups). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
J González de Dios M Moya Benavent MC Sirvent Mayor T Durá Travé 《Canadian Metallurgical Quarterly》1996,45(4):403-408
Cytomegalovirus is the main agent of congenital viral infections. The aim of this study was to compare the incidence of congenital cytomegalovirus infections of two groups of newborns of differing socioeconomic status. Cytomegalovirus was isolated from urine or oropharingeal secretions in 218 children born in a private clinic and 471 born in a public hospital. Positive viral isolates were confirmed with indirect immunofluorescence using monoclonal antibodies. Infection was detected in 12 children (1.82%), four coming from the private clinic (1.86%) and 8 coming from the public hospital (1.81%). Ninety two percent of infected children were asymptomatic. Urine and oropharingeal secretion samples had the same yield for viral isolation. It is concluded that the incidence of congenital cytomegalovirus infection is similar to that described in developed countries. 相似文献
25.
Effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections in young children in Brazil 总被引:1,自引:0,他引:1
ML Barreto LM Santos AM Assis MP Araújo GG Farenzena PA Santos RL Fiaccone 《Canadian Metallurgical Quarterly》1994,344(8917):228-231
A beneficial effect of periodic vitamin A supplementation on childhood mortality has been demonstrated, but the effect on morbidity is less clear. We investigated the effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections (ALRI) in children from northeastern Brazil in a randomised, double-blind, placebo-controlled community trial. 1240 children aged 6-48 months were assigned vitamin A or placebo every 4 months for 1 year. They were followed up at home three times a week, and data about the occurrence and severity of diarrhoea and ALRI were collected. Any child with cough and respiratory rate above 40 breaths per min was visited by a paediatrician. The overall incidence of diarrhoea episodes was significantly lower in the vitamin-A-supplemented group than in the placebo group (18.42 vs 19.58 x 10(-3) child-days; rate ratio 0.94 [95% Cl 0.90-0.98]). The benefit of supplementation was greater as regards severe episodes of diarrhoea; the incidence was 20% lower in the vitamin A group than in the placebo group (rate ratio 0.80 [0.65-0.98]). With the standard definition of diarrhoea (> or = 3 liquid or semi-liquid stools in 24 h) the effect of vitamin A on mean daily prevalence did not reach significance, but as the definition of diarrhoea was made more stringent (increasing number of stools per day), a significant benefit became apparent, reaching for diarrhoea with 6 or more liquid or semi-liquid stools in 24 h a 23% lower prevalence. We found no effect of vitamin A supplementation on the incidence of ALRI. The reduction in severity of diarrhoea may be the most important factor in the lowering of mortality by vitamin A supplementation. 相似文献
26.
PURPOSE: The purpose of this investigation was to evaluate the surgeon's ability to assess various types of globe injury, to determine the force necessary to rupture the globe with these types of injuries, and to determine typical orbital retraction forces used in the clinical setting. MATERIALS AND METHODS: Forty-four enucleated globes from recently killed cows were divided into four equal groups-one uninjured control group, one group with a through-and-through scleral laceration, another group with a subtotal scleral laceration, and the last group with an 18-gauge needle perforation. Twenty-seven boarded or board eligible oral and maxillofacial surgeons were asked to assess one sample from each of the four groups. They were then asked to retract a simulated globe on a custom-fabricated jig to determine clinical retraction forces. Ten globes from each of the four groups were then subjected to forces until rupture on an Instron 8501M mechanical testing unit. Accuracy of the clinical assessment was determined, and means and standard deviations of the retraction forces and globe rupture forces were derived. RESULTS: Through-and-through lacerations were assessed by surgeons with 100% accuracy, subtotal lacerations with 96% accuracy, uninjured globes with 74% accuracy, and perforated globes with 15% accuracy. Globe rupture occurred at 16.72+/-7.87 kg in the control group, 20.36+/-7.87 kg in the perforated group, 15.38+/-6.06 kg in the subtotal laceration group, and 4.94+/-2.56 kg in the through-and-through laceration group. Statistically significant differences (P < .001) were noted between the total laceration group and all other groups. The mean retraction force was 0.35+/-0.47 kg, which was statistically less than the force used in all of the rupture groups (P < .001). CONCLUSIONS: Severe injuries (through-and-through lacerations) were assessed with 100% accuracy by the clinicians, and less severe injuries with less accuracy. Rupture forces for globes with perforations and subtotal lacerations were no different than for the control group, but substantially less than for the total laceration group. The simulated clinical retraction forces were substantially more than the rupture forces in all of the groups, including the through-and-through laceration group. 相似文献
27.
Life table studies were performed in 1996 with Aedes aegypti (L.) during the low (cool/dry) and high (hot/rainy) dengue virus transmission seasons in Puerto Rico. Mated adult females from field-collected pupae were placed individually in cages and divided into 2 treatment groups: one was fed only human blood and the other human blood plus a 10% sucrose solution. Survival and number of eggs laid were recorded daily for each female. During both seasons, age specific survivorship was higher for the blood plus sugar group, groups fed only human blood had higher reproductive outputs (mx), and net replacement rates (Ro) for blood only groups were higher than for those fed blood plus sugar. Intrinsic rates of growth (r) were the same for both treatments during the low (cool/dry) transmission season, but higher for the blood-only treatment during the high (hot/rainy) transmission season. Our results indicate that feeding on only human blood provides an evolutionary advantage to Ae. aegypti females in Puerto Rico. These results are similar to those from an earlier study carried out with Ae. aegypti in Thailand; the advantage of feeding on human blood does not seem to be restricted to a particular geographic region. We also found that the benefits associated with human feeding persist through epidemiologically different times of the year. We conclude that feeding on human blood is reproductively beneficial for Ae. aegypti, which may increase their contact with human hosts, and therefore may influence their vectorial capacity for dengue viruses through frequent feeding on blood. 相似文献
28.
As a complementary modality, therapeutic touch is gaining increasing recognition. Not only are nurses incorporating therapeutic touch into their daily patient care, but patients also are requesting this healing modality. Nurse leaders also use this nursing intervention to weave their vision of healing into their managerial role. 相似文献
29.
LK Malendowicz C Macchi GG Nussdorfer A Markowska 《Canadian Metallurgical Quarterly》1996,11(3):641-645
The effects of a prolonged administration of bradykinin (BK) and/or D-Arg, [Hyp3, D-Phe7]-BK, a specific antagonist of BK receptors (BK-A) (daily subcutaneous injections of 4 nmol/rat for 6 days) on the function of the pituitary-adrenocortical axis were investigated. BK did not change plasma aldosterone concentration (PAC), but markedly lowered that of corticosterone (PBC) and consequently induced a compensatory hypersecretion of ACTH by the pituitary gland. BK-A did not apparently affect the function and growth of the adrenal gland, but, when administered together with BK, markedly raised both PAC and PBC, and provoked a significant atrophy of the adrenal gland, probably due to loss of parenchymal cells. Taken together, these rather puzzling findings do not appear to provide clear evidence for the involvement of BK in the physiological regulation of adrenocortical growth and steroidogenic capacity in rats. 相似文献
30.
JG Gribben GJ Freeman VA Boussiotis P Rennert CL Jellis E Greenfield M Barber VA Restivo X Ke GS Gray 《Canadian Metallurgical Quarterly》1995,92(3):811-815
The regulation of T cell-mediated immune responses requires a balance between amplification and generation of effector function and subsequent selective termination by clonal deletion. Although apoptosis of previously activated T cells can be induced by signaling of the tumor necrosis factor receptor family, these molecules do not appear to regulate T-cell clonal deletion in an antigen-specific fashion. We demonstrate that cross-linking of the inducible T-cell surface molecule CTLA4 can mediate apoptosis of previously activated human T lymphocytes. This function appears to be antigen-restricted, since a concomitant signal T-cell receptor signal is required. Regulation of this pathway may provide a novel therapeutic strategy to delete antigen-specific activated T cells. 相似文献