Caudate nucleus volume and cognitive performance: Are they related in childhood psychopathology?

BACKGROUND: Impaired neuropsychological test performance, especially on tests of executive function and attention, is often seen in children diagnosed with autism spectrum disorders (ASD). Structures involved in fronto-striatal circuitry, such as the caudate nucleus, may support these cognitive abilities. However, few studies have examined caudate volumes specifically in children with ASD, or correlated caudate volumes to cognitive ability. METHODS: Neuropsychological test scores and caudate volumes of children with ASD were compared to those of children with bipolar disorder (BD) and of typically developing (TD) children. The relationship between test performance and caudate volumes was analyzed. RESULTS: The ASD group displayed larger right and left caudate volumes, and modest executive deficits, compared to TD controls. While caudate volume inversely predicted performance on the Wisconsin Card Sorting Test in all participants, it differentially predicted performance on measures of attention across the ASD, BD and TD groups. CONCLUSIONS: Larger caudate volumes were related to impaired problem solving. On a test of attention, larger left caudate volumes predicted increased impulsivity and more omission errors in the ASD group as compared to the TD group, however smaller volume predicted poorer discriminant responding as compared to the BD group.     

Use of a geographic information system to track smelter-related lead exposures in children: North Lake Macquarie, Australia, 1991–2002

Background  

To determine patterns of childhood lead exposure in a community living near a lead and zinc smelter in North Lake Macquarie, Australia between 1991 and 2002.     

Lung mechanics--the inverse problem.

The mechanical properties of the lung are important determinants of its efficacy as a gas exchanging organ. These properties are reflected to a precise degree in the relationships between pressure and flow measured at the mouth. Together with oesophageal pressure, which reflects the pressure in the pleural space, these quantities allow one to usefully indulge in inverse modelling of the lung - that is, identify mathematical models of lung mechanics that give insight into its structure and may be diagnostic of certain diseases. The complexity of such models, however, is limited by the number of distinct components that can be unambiguously resolved from the measured signals. The development of more detailed models requires the availability of experimental methods for obtaining additional input-output information from the lungs. One such method is the so-called alveolar capsule technique which allows alveolar pressures at several sites on the lung surface to be measured directly. This technique has been used in animals to show that the mechanical behaviour of normal lungs in the breathing frequency range is well described by a homogeneously ventilated compartment surrounded by viscoelastic tissue. During bronchoconstriction, however, the lungs can become markedly inhomogeneous resulting from differences in regional resistive and elastic properties. Model ambiguity problems again appear as it becomes impossible to distinguish changes in local resistance from changes in elastance using only the information obtained from alveolar capsules. To push the inverse modelling of the lung one step further, we have recently developed a new technique for quantifying changes in local resistance and elastance by applying broad-band oscillations in flow to the lung through a small hole in the pleura, thereby obtaining an alveolar input impedance.     

Malakoplakia and colorectal adenocarcinoma.

We report a case of malakoplakia in association with colonic adenocarcinoma. Tumour-associated malakoplakia in the gastrointestinal tract is a rare finding, generally confined to the colon. It may be locally aggressive, with invasion of pericolic tissues, but is always located adjacent to the tumour. This contrasts with the often more diffuse, multifocal distribution of colonic malakoplakia in association with other pathologies.     

Smoking and raven IQ

Nicotine has recently been shown to enhance measures of information processing speed including the decision time (DT) component of simple and choice reaction time and the string length measure of evoked potential waveform complexity. Both (DT and string length) have been previously demonstrated to correlate with performance on standard intelligence tests (IQ). We therefore hypothesised that nicotine is acting to improve intellectual performance on the elementary information processing correlates of IQ. In the current experiment we tested this hypothesis using the Raven Advanced Progressive Matrices (APM) test. APM scores were significantly higher in the smoking session compared to the non-smoking session, suggesting that nicotine acts to enhance physiological processes underlying performance on intellectual tasks.     

Zinc in breast milk during prolonged lactation: comparison between the UK and the Gambia

A total of 580 breast milk samples were collected from 56 lactating women living in a rural village community in The Gambia, West Africa, and 92 samples were obtained from 57 lactating women living in Cambridge, England. Total zinc content of each sample was measured by atomic absorption spectrometry, and pooled samples of the Gambian breast milks, representing successive periods of lactation, were fractionated into fat, whey and insoluble casein fractions, to examine zinc distribution. The two sets of milks both exhibited a dramatic decline in total zinc concentrations with increasing duration of lactation, in common with previous studies. However, the UK milks unexpectedly had lower zinc contents at all stages than the Gambian milks. Milk zinc levels were not significantly related to either maternal age or parity in the Gambian women. The proportion of zinc found in the sedimentable fraction remained nearly constant with increasing duration of lactation, but the proportion found in the fat fraction increased and the proportion in the whey fraction declined. These observations are potentially relevant for estimations of milk zinc availability and the fulfillment of zinc requirements by infants, and hence for infant feeding practices.