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At least 127 records · Page 7Linked to original sources

Association between prenatal exposure to methylmercury and cognitive functioning in Seychellois children: a reanalysis of the McCarthy Scales of Children's Ability from the main cohort study.

Methylmercury (MeHg) is a neurotoxicant whose high-dose effects first became known following a number of poisoning outbreaks that occurred worldwide. The primary human exposure is low dosage from fish consumption. Studies of fish-eating populations have not found a consistent pattern of association between exposures and outcomes. Therefore, examining specific areas of cognitive functioning has been suggested as an important approach to determine whether more subtle effects of MeHg exposure are present. In the Seychelles longitudinal study of prenatal and postnatal MeHg exposure from fish consumption and development, the McCarthy Scales of Children's Abilities (MSCA) were administered to children at age 66 months. No association between MeHg exposure and performance on the MSCA General Cognitive Index was identified. We analyzed these data further to determine whether associations were present on specific subscales of the MSCA. The standard MSCA subscales were analyzed. Then, more specific subscales of the MSCA were defined and analyzed utilizing a neuropsychological approach. The subscales were recombined to approximate the domains of cognitive functioning evaluated in the Faroes and New Zealand studies. Analyses of both the standard and the recombined MSCA subscales showed no adverse associations with MeHg exposure and neuropsychological endpoints. A positive association between postnatal MeHg exposure and performance on the MSCA Memory subscale was found. These findings are consistent with previous reports from the Seychelles study in that no adverse effects of MeHg exposure from fish consumption can be detected in this cohort.

Animals↗

Reanalysis and New Measurements of N(2) and CH(4) Adsorption on Ice and Snow.

Numerous literature data indicate that the mean heat of adsorption of a monolayer of N(2) (DeltaQ(N(2))) on ice or snow at 77.15 K, determined by volumetric methods, is highly variable, suggesting that ice surface properties strongly depend on its mode of formation and its thermal history. Less numerous data on CH(4) adsorption show smaller variations of DeltaQ(CH(4)). If such variations are real, the extrapolation to atmospheric chemistry models of adsorption parameters measured on laboratory-made ice may be unwarranted. We have measured CH(4) adsorption on variable amounts of a crushed ice sample, to show that when the total surface area of the sample is below a threshold value, DeltaQ(CH(4)) decreases. We identify the cause of this artifact as an error in the molar budget, because the temperature gradient in the tube connecting the introduction and expansion volumes is not taken into account. Performing an adequate molar budget suppresses this artifact, except for ice samples with very small total surface areas, where the resolution of the manometer becomes a limiting factor and a further decrease in DeltaQ(CH(4)) is observed. Error in DeltaQ(gas) results in large errors in surface area, and we suggest that the value of DeltaQ(gas) obtained can be used to test the reliability of the surface area measurement. Copyright 2000 Academic Press.

Journal Article↗

Surgical site infections: reanalysis of risk factors.

BACKGROUND: Surgical site infections (SSI) are the most common nosocomial infection in surgical patients, accounting for 38% of all such infections, and are a significant source of postoperative morbidity resulting in increased hospital length of stay and increased cost. During 1986-1996 the Center for Disease Control and Prevention's National Nosocomial Infections Surveillance system reported 15,523 SSI following 593,344 operations (2.6%). Previous studies have documented patient characteristics associated with an increased risk of SSI, including diabetes, tobacco or steroid use, obesity, malnutrition, and perioperative blood transfusion. In this study we sought to reevaluate risk factors for SSI in a large cohort of noncardiac surgical patients. METHODS: Prospective data (NSQIP) were collected on 5031 noncardiac surgical patients at the Veteran's Administration Maryland Healthcare System from 1995 to 2000. All preoperative risk factors were evaluated as independent predictors of surgical site infection. RESULTS: The mean age of the study cohort was 61 plus minus 13. SSI occurred in 162 patients, comprising 3.2% of the study cohort. Gram-positive organisms were the most common bacterial etiology. Multiple logistic regression analysis documented that diabetes (insulin- and non-insulin-dependent), low postoperative hematocrit, weight loss (within 6 months), and ascites were significantly associated with increased SSI. Tobacco use, steroid use, and chronic obstructive pulmonary disease (COPD) were not predictors for SSI. CONCLUSION: This study confirms that diabetes and malnutrition (defined as significant weight loss 6 months prior to surgery) are significant preoperative risk factors for SSI. Postoperative anemia is a significant risk factor for SSI. In contrast to prior analyses, this study has documented that tobacco use, steroid use, and COPD are not independent predictors of SSI. Future SSI studies should target early preoperative intervention and optimization of patients with diabetes and malnutrition.

Aged↗

A reanalysis of the New York State prenatal diagnosis data on Down's syndrome and paternal age effects.

This paper reanalyzes the data from the Hook and Cross (1982) paper in this journal concerning the association between Down's syndrome and paternal age. The New York State (NYS) data are compared with a large European collaborative study by Ferguson-Smith and Yates (1984). The maternal-age-dependent risks in the NYS data were found to be significantly higher than in the European data. When the NYS data was divided into three groups by means of the paternal age, a marked two-peaked distribution was found. The maternal-age-dependent risk was high when the fathers were up to 33 years old, low when the fathers' ages were 34-39 years and high again when the fathers were at least 40 years old. The differences were significant. The results speak in favour of the existence of temporal, geographic, or environmental variations in the risk for de novo trisomy 21, as well as of a paternal age effect. The existence of a "paternal age effect" in at least some populations is confirmed. If the results of this paper are confirmed in other investigations, it will be necessary to revise present genetic counselling rules towards far more individually specified considerations.

Adult↗

A reanalysis of the impact of non celebrity suicides. A research note.

Previous work on suicide and the media has neglected theoretical issues. Some work has implied that only celebrity suicides can be expected to trigger additional suicides in the real world. The present study focuses on non celebrity suicides. Correcting coding errors in a previous work, it finds that the suicides of non celebrities are associated with increases in the national suicide rate. An index of publicized celebrity suicide stories was, however, more closely associated to increases in suicide than the publicized non celebrity stories. The model explains 90 percent of the variance in monthly suicide rates.

Cross-Sectional Studies↗

Behavioral responses to novelty in mice: a reanalysis.

A recently proposed searching procedure for scale transformations and models was applied to previously obtained data on rearing responses and locomotor activity in mice from two inbred selection lines (SRH and SRL) and four hybrid generations. Logarithmic transformation provided the most appropriate scale of measurement for both behaviors. For rearing, the simple additive model was adequate, thus validating the earlier findings. However, contrary to the previous conclusions, an additivity-dominance model fitted the locomotion data best. These results demonstrate the usefulness of the procedure described.

Animals↗

The behavioral economics of concurrent drug reinforcers: a review and reanalysis of drug self-administration research.

In economics, goods can function as substitutes, complements, or be independent of one another. These concepts refer to increases, decreases, or no change in the consumption of one item as the price of a second item increases. This review examined whether these economic terms can be used to describe relationships between concurrently available reinforcers in drug self-administration research. Sixteen drug self-administration studies that examined the effects of concurrent reinforcers were identified through a MEDLINE search. Across these studies, the following substances were employed: caffeinated coffee, cocaine, etonitazene, ethanol, heroin, food, methadone, morphine, nicotine cigarettes, pentobarbital, phencyclidine, sucrose and water. These studies were reanalyzed and the results were shown to be consistent with these economic notions. These analyses also showed that relationships among the concurrently available reinforcers were reliable within and across studies, that concurrently available reinforcers can affect each other asymmetrically, and that the relative price may determine the magnitude of effect for substitutes. These findings suggest that these economic concepts may be useful in characterizing the type and magnitude of interactions between concurrently available reinforcers and may suggest potential mechanisms that determine these relationships.

Alcohol Drinking↗

Sex differences in spatial memory: a reanalysis of block tapping long-term memory according to the short-term memory level.

This paper analyzes the spatial memory performance of 495 subjects. Both short-term and long-term memory have been analyzed by means of the Corsi block-tapping test. We provide separate norms for the learning of a supra-span sequence according to the level of spatial short-term memory. The long-term memory of males and females was compared in groups matched for spatial short-term memory, and the gender effect was never found to be significant. This finding is discussed in relation to the nature of sex differences in spatial abilities.

Educational Status↗

Reanalysis of the first case of Alzheimer's disease.

When a disease becomes as important as Alzheimer's dementia, there is a natural interest in its medical history and in the origin of the underlying disease concept. Key to understanding Alois Alzheimer's views on the disease, which was named after him, are the histological sections of the cases he saw. This histological material was rediscovered in Munich in 1992 and 1997 (Neurogenetics 1997, 1:73-80; 1998, 1:223-228). An extensive neuropathological and molecular genetic analysis of the tissue is currently being carried out. The present article summarizes the history of the rediscovery and provides an analysis of the neuropathology of Alois Alzheimer's first case, Auguste D.

Alzheimer Disease↗

Organizational and activational effects of sex steroids on brain and behavior: a reanalysis.

The actions of sex steroids on brain and behavior traditionally have been divided into organizational and activational effects. Organizational effects are permanent and occur early in development; activational effects are transient and occur throughout life. Over the past decade, experimental results have accumulated which do not fit such a simple two-process theory. Specifically, the characteristics said to distinguish organizational and activational effects on behavior are sometimes mixed, as when permanent effects occur in adulthood. Attempts to determine whether specific cellular processes are uniquely associated with either organizational or activational effects are unsuccessful. These considerations blur the organizational-activational distinction sufficiently to suggest that a rigid dichotomy is no longer tenable.

Animals↗

On estimating processing variance: commentary and reanalysis of Kail's "Developmental functions for speeds of cognitive processes".

A recent paper by Kail (1988) in this journal appears to contain a significant error in the data analysis. The "goodness-of-fit" coefficients reported which suggest that overall about 94% of the variance can be accounted for by the model seem to be a substantial overestimation as a result of inappropriate procedures for statistical modeling. Using the data made available to us by Kail, we have reanalyzed these results. The corrected values range from 0.9 to 92.1% for the individual tasks with an overall average between 40 and 60%. We suggest that the support for the original conclusions is considerably weaker than reported.

Aptitude↗

Affective disorders and ABO blood groups: new data and a reanalysis of the literature using the logistic transformation of proportions.

No statistically significant associations were found between ABO blood group distributions and RDC subtype diagnoses in 79 subjects with unipolar (single episode and recurrent) and bipolar major depressive disorder using data from our sample. We discuss methodological issues related to the control samples and choice of statistical methods in the reported studies which have looked for associations between ABO blood types and patients diagnosed as having an affective disorder. After presenting our rationale for employing the logarithm of the cross product ratio (lambda) in place of the more traditionally utilized chi-squared, we used lambda to reanalyze the original data from nine studies in the literature. The individual studies are equivocal on the basic issue of an association between type O blood and bipolar I illness, either compared to controls or to recurrent unipolar patients. The combined (weighted average) measure of association indicates a small but definite association, but statistical analysis of the dispersion of the individual estimates around this combined estimate reveals that the studies have a higher degree of heterogeneity in results than expected by chance. The consequences of this finding are discussed, and possible explanations are offered.

ABO Blood-Group System↗