肝豆状核变性10例迟诊分析

目的　为使肝豆状核变性病人得以及时的诊断。方法　回顾分析了1989年以来所遇10例迟诊病例的情况。结果　某些病例在较长时间内临床表现比较单一、多系统症状出现不同步或出现的器官受损表现在肝、脑病状之前是造成迟诊的重要原因。结论　提高对本病的认识是本病及时诊断的关键。     

Sensitivity to delay of reinforcement in two animal models of attention deficit hyperactivity disorder (ADHD)

An altered response to reinforcement has been proposed as a mechanism underlying many of the symptoms of attention deficit hyperactivity disorder (ADHD). We measured sensitivity to delay of reinforcement in two animal models of ADHD, the spontaneously hypertensive rat (SHR) and a newly proposed model, the genetically hypertensive (GH) rat. A task previously used to measure effects of delay of reinforcement in children with ADHD was adapted for use in the present experiment. The SHR and GH rats were compared to their respective genetic control strains, Wistar-Kyoto (WKY), and Wistar (WI). The experimental task required pressing one of two available levers each trial. One lever delivered an immediate reinforcement, and the other lever a delayed reinforcement. Both the SHR and GH strains allocated significantly more responses to the immediately reinforced lever than their genetic control strains. Individual instances of reinforcement differentially affected response allocation in the GH but not the SHR. These findings support the use of the SHR and GH rat to model altered response to reinforcement, and demonstrate the additional value of the GH strain to model the effects of individual instances of reinforcement in children with ADHD.     

Central nicotinic receptor agonists ABT-418, ABT-089, and (–)-nicotine reduce distractibility in adult monkeys

 Increased distractibility is associated with both Alzheimer’s disease and attention deficit disorder. The present study examined the effects of (–)-nicotine and the novel central nicotinic receptor (nAChR) agonists ABT-418 [(S)-3-methyl-2-pyrrolidinyl)isoxazole] and ABT-089 [2-methyl-3-(2-(S)-pyrrolindinylmethoxy)- pyridine dihydrochloride] on the delayed recall accuracy of adult monkeys exposed to distracting stimuli. Unpredictable exposure to a random visual array produced marked decrements in recall accuracy on trials with the shortest delay intervals, reducing the accuracy on these trials by 23.4%. Intramuscular (IM) administration of (–)-nicotine, in doses of 5.4–43.3 nmol/kg, attenuated the effect of the distractor, but did not completely prevent it. Both ABT-418 (2.0–16.2 nmol/kg, IM) and ABT-089 (16.4–32.8 nmol/kg, IM) prevented distractibility, producing increases of 7.5–25.0% in accuracy on trials disrupted by distractor exposure. Further, both compounds also improved accuracy on trials during which distractors were not presented, an effect which was not observed after (–)-nicotine administration. Nicotinic-mediated side effects were not observed following administration of any compound. Thus, nAChR stimulation reduces distractibility in adult monkeys and may, therefore, represent a target for the pharmacologic treatment of disorders associated with susceptibility to distraction. ABT-418 and ABT-089 appear to be particularly useful in this regard, a likely result of their selective agonist activity at nAChRs expressed in the brain. Received: 14 May 1997 / Final version: 19 August 1997     

Low doses of methylphenidate (Ritalin) may alter the delay-of-reinforcement gradient

The present study investigated effects of methylphenidate on spatio-temporal distributions of responses generated by a fixed interval 60-s schedule of reinforcement. A response panel with 20 different response locations (holes) made it possible to distinguish effects of the drug on the procedurally-correct response (correct according to the contingencies) and effects on other topographically similar responses acting as functionally-adequate responses. Detailed flow charts show how the dynamics of responding changed with dose and segment of the fixed interval. The number of holes visited was increased after low and medium doses, but decreased after high doses. The spatial differences between responses in the initial and the final parts of the fixed interval gradually disappeared after 6 mg/kg or higher doses as the functionally-adequate responses moved to earlier segments of the fixed interval. Few results could, however, be described as response rate dependent. Distributions of responses around the correct hole illustrated differences between procedurally-correct and functionally-adequate classes. The number of holes included in the latter class changed by dose in an inverted U-shaped fashion. Perseverations and stereotyped responding increased with increasing dose. Most of the effects may be described as motor stimulatory. One way of explaining the stimulatory effect is in terms of a lengthened delay-of-reinforcement gradient. The rate-dependent effect of methylphenidate on the procedurally-correct class after some doses may have been due to the combined effects of a lengthened delay gradient increasing the response rates early in the interval and interference from perseverations having their most detrimental effects on the high rates late in the interval. Offprint request to: T. Sagvolden     

The effects of two different delay phenomena in flow-through venous flaps

The purpose of this study was to investigate the effects of two different types of pedicle manipulation two weeks prior to harvesting of flow-through venous flaps (FTVF). The dorsal aspect of the ear of New Zealand white rabbits was used in the investigation. Two different delay procedures (manipulation of pedicle) were performed and compared to the single stage harvesting of FTVF. In the first delay (arterial ligation group), the central artery was ligated at the proximal and distal edge of the flap, and the flap was harvested after two weeks. In the second delay (arteriovenous shunt group), the central artery was anastomosed to the lateral caudal vein at the proximal part of the ear to create an arteriovenous shunt and to increase blood flow in the venous system. The FTVF was again harvested two weeks after the creation of the arteriovenous shunt. The survival rates and the superficial flap necrosis rates of the two different delay groups were compared to the nondelayed group.The mean survival of the arterial ligation group (82%) and the arteriovenous shunt group (80%) show significantly increased survival when compared to the nondelayed group (44%). The superficial flap necrosis rates in the two delay groups were also decreased when compared to the non delayed group.     

Minimum energy control of time-delay systems via walsh functions

This paper presents a Walsh function approach to the minimum energy control of linear systems with time delay satisfying given conditions on the terminal state. Walsh operational matrices for integration, delay and advance¹ are employed in solving the related state and costate equations containing terms with advanced and delayed arguments. The technique of extension of the solution with a single term Walsh series² is adapted to the case of differential equations with delay and advance terms, leading to an enormous reduction in computational effort. The results may be computed in two forms, piecewise constant or discrete, satisfying both the energy and terminal conditions.     

Timing of steps and reasons for delays in obtaining abortions in the United States

OBJECTIVE: We studied the steps in the process of obtaining abortions and women's reported delays in order to help understand difficulties in accessing abortion services. METHODS: In 2004, a structured survey was completed by 1209 abortion patients at 11 large providers, and in-depth interviews were conducted with 38 women at four sites. RESULTS: The median time from the last menstrual period to suspecting pregnancy was 33 days; the median time from suspecting pregnancy to confirming the pregnancy was 4 days; the median time from confirming the pregnancy to deciding to have an abortion was 0 day; the median time from deciding to have an abortion to first attempting to obtain abortion services was 2 days; and the median time from first attempting to obtain abortion services to obtaining the abortion was 7 days. Minors took a week longer to suspect pregnancy than adults did. Fifty-eight percent of women reported that they would have liked to have had the abortion earlier. The most common reasons for delay were that it took a long time to make arrangements (59%), to decide (39%) and to find out about the pregnancy (36%). Poor women were about twice as likely to be delayed by difficulties in making arrangements. CONCLUSIONS: Financial limitations and lack of knowledge about pregnancy may make it more difficult for some women to obtain early abortion.