Volumetric magnetic resonance imaging study of the brain in subjects with sex chromosome aneuploidies

OBJECTIVES: Cognitive impairment has been reported in people with sex chromosome aneuploides (SCAs) and it has been proposed that the presence of an extra sex chromosome may have an adverse effect on neurodevelopment. This study examines the hypothesis with structural MRI of the brain. METHODS: Thirty two subjects with SCA (XXX (n=12), XYY (n=10), and XXY (n=10)) from a birth cohort study were matched groupwise for age, parental social class, and height with normal controls (13 female, 26 male). Brain MRI, measurements of IQ, and a structured psychiatric interview were performed. RESULTS: The XXX females and XXY males had significantly smaller whole brain volumes than controls of the same phenotypic sex (p=0.003 and p相似文献   

Placing hippocampal single-unit studies in a historical context.

A profound increase in the study of the role of the hippocampus in behavior and cognitive processing resulted from the startling discovery by O'Keefe and Dostrovsky in 1971 that hippocampal neurons fire selectively in different regions or "place fields" of an environment. That discovery spawned a comprehensive theory of hippocampal function that was elucidated in the publication, The Hippocampus as a Cognitive Map by O'Keefe and Nadel in 1978. According to the theory, the hippocampus serves as the neural substrate for maps of allocentric space. The goal of this paper is to revisit the historical background for the development of the cognitive map theory and to examine the context in which the theory and the phenomenon of place field activity began to gain acceptance by the scientific community. While subsequent research has led some to question if the theory can adequately account for all consequences of hippocampal lesions and all the correlates of hippocampal cellular activity, it is clear the theory has stood the test of time and has been successful in generating an enormous amount of fruitful research.     

Risk factors for rape, physical assault, and posttraumatic stress disorder in women: examination of differential multivariate relationships

The National Women's Study, a 2-year, three-wave longitudinal investigation, employed a national probability sample of 3,006 adult women to: (a) identify separate risk factors for rape and physical assault, and (b) identify separate risk factors associated with post-rape posttraumatic stress disorder (PTSD) and post-physical assault PTSD. This investigation differed from previous studies in that it prospectively examined risk factors at the multivariate, as opposed to univariate level. Overall, past victimization, young age, and a diagnosis of active PTSD increased women's risk of being raped. By contrast, past victimization, minority ethnic status, active depression, and drug use were associated with increased risk of being physically assaulted. Risk factors for PTSD following rape included a history of depression, alcohol abuse, or experienced injury during the rape. However, risk factors for PTSD following physical assault included only a history of depression and lower education.     

beta-lactam antibiotics. II. Structure-activity relationships of 6-[alpha-(alpha'-ureido-acylamino) acylamino] penicillanic acids.

The influence on the structure-activity relationships (S.A.R.) of the stereochemistry and various alkyl, aryl, aralkyl and heterocyclic substituents at the two chiral centres in the dipeptide side-chain of a new series of penicillins was examined. In many cases the effects of these changes had a pronounced influence on the degree of activity against Gram-positive and especially Gram-negative bacteria. Several compounds indicated that the size, shape and spatial disposition of a substituent were the parameters of importance in influencing activity, rather than it lipophilic or electronic character. The most active homologues in the series provided broad-spectrum penicillins which in terms of their in vitro antibacterial properties showed improvements over certain of the marketed penicillins. Thus 6-[D-alpha(alpha'-ureidoacyl-amino)acylamino]penicillanic acids were found which had a carbenicillin-like profile, with improvements against Pseudomonas aeruginosa, Klebsiella aerogenes, sensitive and beta-lactamase-producing Gram-positive cocci.     

Renotrophic factors in urine

Our previous observations of increased renal protein synthesis in rats subjected to the constant intravenous reinfusion of half their urine output has suggested that the circulatory retention of renotrophic factors in urine is capable of stimulating renal growth. In the present studies, using this same model of "half-urine-reinfusion," which is designed to produce a selective halving of renal excretory function, we have demonstrated significant increases in total DNA content and the incorporation of tritiated thymidine in renal DNA. In addition, a bioassay method was developed in which an assay rat, given an intravenous infusion of urine from another rat, exhibited increases in the incorporation of thymidine into renal DNA and the incorporation of radiolabelled choline into renal phospholipid. This renotrophic activity in the urine was only minimally decreased by heating to 100 degrees C for 30 min and was confined to ultrafiltration fractions retained on a membrane with a nominal 10,000-dalton solute rejection. Removal of one kidney from the rats from which the urine was obtained led to only a modest and transient reduction in the excretion of renotrophic activity, suggesting that the urinary renotrophic factors are of circulatory, not renal, origin. Isolated renal cortical fragments incubated with an ultrafiltration retentate of urine displayed a dose-dependent increase in choline incorporation into phospholipid, suggesting a direct action of the factors on kidney tissue. Finally, no evidence of stimulation of either DNA or phospholipid synthesis could be seen in hepatic tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Simulation of emergency medical service scheduling

Efficient allocation of resources is essential in any activity, but experimenting to determine appropriate levels risks a reduction in services that could be dangerous in a healthcare operation. Computer simulations offer a risk-free environment for testing alternate resource levels and balancing costs and services. This article describes the use of a simulation to determine appropriate staffing levels for an emergency medical service.     

Angiography in chronic/recurrent gastrointestinal bleeding: a nine year study.

Undiagnosed chronic/recurrent gastrointestinal bleeding, as defined, is a severe problem to those afflicted, both physically and psychologically as well as socioeconomically. During the past nine years, 60 such patients received aortography and panvisceral arteriography (that is, celiac, superior mesenteric, and inferior mesenteric arteriography) in a search for the lesions that may be responsible for the bleeding. Results of angiography were "positive" in 26 patients for a diagnostic yield of 43 per cent. Fifteen of the 26 patients with positive angiographic findings demonstrated arteriovenous malformations of the gastrointestinal tract. Two separate lesions were identified in three patients. This series is compared with other published series of angiography for chronic gastrointestinal bleeding. One difference from the other series is the demonstration of three patients with arteriovenous malformation of the gastric antrum. The diagnostic angiographic features of this condition are presented, along with the interestng finding of état mammelonné in two of the three patients. Another difference from the other series is the demonstration of four arteriovenous malformations involving the left side of the colon, whereas other series report none in this location. One possible explanation for this descrepancy is our routine use of inferior mesenteric arteriography in all cases of chronic gastrointestinal bleeding. Ten arteriovenous malformations of the colon are reported along with a review of the angiographic diagnostic features in this condition. The precise incidence of false-positive and false-negative diagnoses is unknown since surgery was not performed on all patients. However, each patient studied represented a total failure, by traditional diagnostic studies, to determine the cause of bleeding. The incidence of positive findings with angiography (43 per cent) in patients with undiagnosed chronic/recurrent gastrointestinal bleeding is sufficient to encourage the continued use of panvisceral arteriography in this condition.     

Memory impairment in out-of-hospital cardiac arrest survivors is associated with global reduction in brain volume, not focal hippocampal injury

BACKGROUND AND PURPOSE: More than 30% of out-of-hospital cardiac arrest (OHCA) survivors suffer significant memory impairment. The hippocampus may be vulnerable to hypoxic injury during cardiac arrest. The purpose of this study was to determine whether selective hippocampal injury is the substrate for this memory impairment. METHODS: Seventeen OHCA survivors and 12 patients with uncomplicated myocardial infarction were studied. OHCA survivors were divided into those with impaired and intact memory. Memory was assessed by use of the Rivermead Behavioural Memory Test and Doors and People Test. MRI was used to determine intracranial, whole-brain, amygdala-hippocampal complex, and temporal lobe volumes. Brain structure was also examined by statistical parametric mapping. RESULTS: Left amygdala-hippocampal volume was reduced in memory-impaired OHCA victims compared with control subjects (mean 3. 93 cm(3) and 95% CI 3.50 to 4.36 cm(3) versus mean 4.65 cm(3) and 95% CI 4.37 to 4.93 cm(3); P=0.002). Left temporal lobe and whole-brain volumes were also reduced. There were no differences in amygdala-hippocampal volume indexed against ipsilateral temporal lobe volume. Significant correlations were observed between total brain volume and Rivermead Behavioural Memory Test (r=0.56, P<0.05) and Doors and People Test (r=0.67, P<0.01) scores in OHCA survivors. Both recall and recognition were compromised in memory-impaired subjects. Statistical parametric mapping did not detect focal brain abnormalities in these subjects. Global cerebral atrophy was confirmed by qualitative assessment. CONCLUSIONS: Memory impairment in OHCA survivors is associated with global cerebral atrophy, not selective hippocampal damage. Rehabilitation protocols need to account for the global nature of the brain injury.     

Assault,PTSD, Family Substance Use,and Depression as Risk Factors for Cigarette Use in Youth: Findings from the National Survey of Adolescents

A national household probability sample of 4,023 adolescents aged 12 to 17 years was surveyed by telephone via structured clinical interview to determine the impact of familial substance use, sexual and physical assault, witnessed violence, depression and posttraumatic stress disorder (PTSD) on risk of smoking. Results indicated that familial substance use increased risk of smoking only for boys and sexual assault or depression increased risk of smoking only for girls. Age, Caucasian ethnicity, and experiencing physical assault or witnessing violence elevated risk of current cigarette use for both genders. By contrast, PTSD per se was not associated with increased risk of smoking, after the effects of other variables were controlled.