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121.
RJ O''Hara J Greenman PJ Drew AW McDonald GS Duthie PW Lee JR Monson 《Canadian Metallurgical Quarterly》1998,41(4):460-463
OBJECTIVE: Spontaneous spinal epidural hematoma (SSEH) is an idiopathic accumulation of blood in the vertebral epidural space without identifiable predisposing factors. First reported in 1869, the clinical outcome in children younger than 18 years old has not been clearly delineated. DESIGN: A comprehensive review of the English language literature revealed 26 patients younger than 18 years old with reported clinical outcomes. The 27th case is presented. RESULTS: Complete neurologic recovery occurred in 14 of 27 (52%) patients, partial recovery in 12 of 27 (44%) patients, and death in 1 of 27 (4%) patients. CONCLUSION: There is an overall good prognosis for neurologic recovery in children who experience SSEH. 相似文献
122.
W Wuyts W Van Hul K De Boulle J Hendrickx E Bakker F Vanhoenacker F Mollica HJ Lüdecke BS Sayli UE Pazzaglia G Mortier B Hamel EU Conrad M Matsushita WH Raskind PJ Willems 《Canadian Metallurgical Quarterly》1998,62(2):346-354
In an in-vitro preparation of gastric mucosae of Rana pipiens, the effect of adding melittin to a concentration of 5x10-6 M in the secretory solution on the transepithelial potential difference (PD), resistance (R) and short-circuit current (Isc) was studied. In 20 min, melittin decreased the PD by 9.3 mV and R by 148 ohm cm2. These changes can be explained by a decrease in the resistance, RP, of the paracellular pathway. To determine whether specific-ion pathways were responsible for the decrease in R, the effect of melittin on the partial conductances of Cl-, K+ and Na+ was also studied using the ion substitution method. Melittin decreased the PD response to changes in nutrient Na+, K+ and Cl- and the PD response to changes in secretory Cl-, but did not affect PD responses to changes in secretory Na+ or K+. Therefore, melittin decreased the nutrient membrane partial conductances of Cl-, K+ and Na+ and secretory membrane partial conductance of Cl-, without affecting the secretory partial conductances of Na+ or K+. Initially, melittin increased Isc in regular and Cl--free but not in Na+-free solutions. There was a delayed decrease in Isc. The results indicate that melittin decreases RP, increases the Na+ conductance of the secretory membrane and inhibits, eventually, the Na+/K+-ATPase pump. 相似文献
123.
M Shams MD Kilby DA Somerset AJ Howie A Gupta PJ Wood M Afnan PM Stewart 《Canadian Metallurgical Quarterly》1998,13(4):799-804
The evolutionary theory of aging predicts that the equilibrium gene frequency for deleterious mutations should increase with age at onset of mutation action because of weaker (postponed) selection against later-acting mutations. According to this mutation accumulation hypothesis, one would expect the genetic variability for survival (additive genetic variance) to increase with age. The ratio of additive genetic variance to the observed phenotypic variance (the heritability of longevity) can be estimated most reliably as the doubled slope of the regression line for offspring life span on paternal age at death. Thus, if longevity is indeed determined by late-acting deleterious mutations, one would expect this slope to become steeper at higher paternal ages. To test this prediction of evolutionary theory of aging, we computerized and analyzed the most reliable and accurate genealogical data on longevity in European royal and noble families. Offspring longevity for each sex (8409 records for males and 3741 records for females) was considered as a dependent variable in the multiple regression model and as a function of three independent predictors: paternal age at death (for estimation of heritability of life span), paternal age at reproduction (control for parental age effects), and cohort life expectancy (control for cohort and secular trends and fluctuations). We found that the regression slope for offspring longevity as a function of paternal longevity increases with paternal longevity, as predicted by the evolutionary theory of aging and by the mutation accumulation hypothesis in particular. 相似文献
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125.
Acute and chronic antidepressant drug treatments respectively decrease and increase the aggressive behaviour of resident rats during encounters with unfamiliar conspecifics. We have now examined the effect of the 5-hydroxytryptamine1A receptor antagonist, WAY-100635, on fluoxetine-, paroxetine- or venlafaxine-induced changes in aggression. WAY-100635 (0.1 mg/kg), which did not modify behaviour when given alone, potentiated the venlafaxine (5.54 mg/kg)-induced reduction in aggression after acute treatment and, during chronic treatment, accelerated the fluoxetine (0.34 mg/kg/day)-induced increase in aggression, from day 5 to day 2. A similar change in time course was seen with paroxetine (0.33 mg/kg/day), although the increase in aggression was smaller. Venlafaxine (5.54 mg/kg/day, alone or co-administered with WAY-100635) increased aggression by day 2. During chronic treatment, therefore, venlafaxine, at the dose used, had a more rapid onset of action than either fluoxetine or paroxetine, whereas the fluoxetine- and paroxetine-, but not the venlafaxine-, induced increase in aggression was accelerated by WAY-100635. These studies further support the hypothesis that selective blockade of the 5-hydroxytryptamine1A receptor augments the effects of antidepressant drugs in an animal model predictive of antidepressant activity, presumably by concomitant blockade of the somatodendritic 5-hydroxytryptamine1A autoreceptor-mediated negative feedback system of serotonergic neurones. 相似文献
126.
127.
EI Levy DK Resnick PJ Jannetta T Lovely DJ Bissonette 《Canadian Metallurgical Quarterly》1997,27(5):238-241
Hemifacial spasm (HFS), generally a disease of the elderly, is caused by vascular compression of the seventh nerve. Vascular compression is thought to result from atherosclerotic changes within the vessels of the posterior fossa, and therefore rarely presents in childhood. Here we describe our experience with 12 patients with onset of HFS during childhood (age 18 or less) and who had surgical exploration of the cerebellopontine angle. These patients represent less than 1.2% of the patient population with HFS operated upon at this institution during the study period. Nine patients had follow-up data extending over 83 months. All 12 patients were found to have microvascular compression of the seventh nerve at the time of surgery. The most common operative finding was compression of the seventh nerve by a vein, alone or in combination with a branch of the anterior inferior cerebellar artery. At the time of discharge and after a mean follow-up period of 125 months, microvascular decompression resulted in complete relief of spasm in 67% of the patients. 相似文献
128.
GP Reddy CY Tiarks L Pang J Wuu CC Hsieh PJ Quesenberry 《Canadian Metallurgical Quarterly》1997,90(6):2293-2299
Hematopoietic stem cells purified from mouse bone marrow are quiescent with less than 2% of Lin- Hoechst(low)/Rhodamine(low) (Lin- Ho(low)/Rho(low)) and 10% to 15% of Lin-/Sca+ cells in S phase. These cells enter proliferative cycle and progress through G1 and into S phase in the presence of cytokines and 5% heat-inactivated fetal calf serum (HI-FCS). Cytokine-stimulated Lin- Ho(low)/Rho(low) cells took 36 to 40 hours to complete first division and only 12 hours to complete each of 5 subsequent divisions. These cells require 16 to 18 hours to transit through G0/G1 period and 28 to 30 hours to enter into mid-S phase during the first cycle. Up to 56% of Lin- Rho(low)/Ho(low) cells are high-proliferative potential (7 factor-responsive) colony-forming cells (HPP-CFC). At isolation, HPP-CFC are quiescent, but after 28 to 30 hours of culture, greater than 60% are in S phase. Isoleucine-deprivation of Lin- Ho(low)/Rho(low) cells in S phase of first cycle reversibly blocked them from entering into second cycle. After the release from isoleucine-block, these cells exhibited a G1 period of less than 2 hours and entered into mid-S phase by 12 hours. Thus, the duration of G1 phase of the cells in second cycle is 4 to 5 times shorter than that observed in their first cycle. Similar cell cycle kinetics are observed with Lin-/Sca+ population of bone marrow cells. Stem cell factor (SCF) alone, in the presence of HI-FCS, is as effective as a cocktail of 2 to 7 cytokines in inducing quiescent Lin-/Sca+ cells to enter into proliferative cycle. Aphidicolin treatment reversibly blocked cytokine-stimulated Lin-/Sca+ cells at G1/S boundary, allowing their tight synchrony as they progress through first S phase and enter into second G1. For these cells also, SCF alone is sufficient for their progression through S phase. These studies indicate a very short G1 phase for stem cells induced to proliferate and offer experimental approaches to synchronize murine hematopoietic stem cells. 相似文献
129.
DJ Hazuda PJ Felock JC Hastings B Pramanik AL Wolfe 《Canadian Metallurgical Quarterly》1997,71(9):7005-7011
Previous in vitro analyses have shown that the human immunodeficiency virus type 1 (HIV-1) integrase uses either manganese or magnesium to assemble as a stable complex on the donor substrate and to catalyze strand transfer. We now demonstrate that subsequent to assembly, catalysis of both 3' end processing and strand transfer requires a divalent cation cofactor and that the divalent cation requirements for assembly and catalysis can be functionally distinguished based on the ability to utilize calcium and cobalt, respectively. The different divalent cation requirements manifest by these processes are exploited to uncouple assembly and catalysis, thus staging the reaction. Staged 3' end processing and strand transfer assays are then used in conjunction with exonuclease III protection analysis to investigate the effects of integrase inhibitors on each step in the reaction. Analysis of a series of related inhibitors demonstrates that these types of compounds affect assembly and not either catalytic process, therefore reconciling the apparent disparate results obtained for such inhibitors in assays using isolated preintegration complexes. These studies provide evidence for a distinct role of the divalent cation cofactor in assembly and catalysis and have implications for both the identification and characterization of integrase inhibitors. 相似文献
130.
KC Kocis PJ Radell WI Sternberger JE Benson RJ Traystman DG Nichols 《Canadian Metallurgical Quarterly》1997,83(5):1654-1659
Clinically, a noninvasive measure of diaphragm function is needed. The purpose of this study is to determine whether ultrasonography can be used to 1) quantify diaphragm function and 2) identify fatigue in a piglet model. Five piglets were anesthetized with pentobarbital sodium and halothane and studied during the following conditions: 1) baseline (spontaneous breathing); 2) baseline + CO2 [inhaled CO2 to increase arterial PCO2 to 50-60 Torr (6.6-8 kPa)]; 3) fatigue + CO2 (fatigue induced with 30 min of phrenic nerve pacing); and 4) recovery + CO2 (recovery after 1 h of mechanical ventilation). Ultrasound measurements of the posterior diaphragm were made (inspiratory mean velocity) in the transverse plane. Images were obtained from the midline, just inferior to the xiphoid process, and perpendicular to the abdomen. M-mode measures were made of the right posterior hemidiaphragm in the plane just lateral to the inferior vena cava. Abdominal and esophageal pressures were measured and transdiaphragmatic pressure (Pdi) was calculated during spontaneous (Sp) and paced (Pace) breaths. Arterial blood gases were also measured. Pdi(Sp) and Pdi(Pace) during baseline + CO2 were 8 +/- 0.7 and 49 +/- 11 cmH2O, respectively, and decreased to 6 +/- 1.0 and 27 +/- 7 cmH2O, respectively, during fatigue + CO2. Mean inspiratory velocity also decreased from 13 +/- 2 to 8 +/- 1 cm/s during these conditions. All variables returned to baseline during recovery + CO2. Ultrasonography can be used to quantify diaphragm function and identify piglet diaphragm fatigue. 相似文献