The influence of environment and life-history traits on the distribution of genes and individuals: a comparative study of 11 rainforest trees.

This study investigates patterns of genetic connectivity among 11 co-distributed tropical rainforest tree species from the genus Elaeocarpus across a biogeographic barrier, the Black Mountain Corridor (BMC) in the Australian Wet Tropics (AWT). We analysed a combination of allelic and flanking region sequence data from microsatellite markers, and evaluated the relative influence of environmental preferences and functional traits on genetic diversity and gene flow. The results indicate that only in three species geographic structuring of haplotype distribution reflects a north vs. south of the BMC pattern. Environmental factors linked with altitude were recognized as affecting genetic trends, but the selective processes operating on upland species appear to be associated with competitiveness and regeneration opportunities on poor soil types rather than climate variables alone. In contrast to previous observations within southeastern Australian rainforests, genetic differentiation in the AWT appears to be associated with small-fruited rather than large-fruited species, highlighting how external factors can influence the dispersal dimension. Overall, this study emphasizes the importance of considering functional and environmental factors when attempting generalizations on landscape-level patterns of genetic variation. Understanding how plant functional groups respond to environmental and climatic heterogeneity can help us predict responses to future change.

Delayed neurological deterioration following carbon monoxide poisoning: MRI findings.

We present two patients with delayed neurological deterioration following apparent recovery from carbon monoxide poisoning in whom magnetic resonance imaging showed abnormalities. In the first patient, cortical grey matter abnormalities were seen without white matter changes. Visual evoked potentials were, however, abnormal. In the second, diffuse white matter lesions were detected. In neither patient were basal ganglia lesions seen.

Chlormethiazole in status epilepticus--three cases.

Despite the use of barbiturates, phenytoin sodium and diazepam given intravenously, status epilepticus continued in the three cases described until chlormethizaole (Heminevrin) was administered, when rapid resolution of the status occurred.

Neuropsychiatric relapse following acute carbon monoxide poisoning--the contribution of electroconvulsive therapy.

Four cases are described in which, after apparent recovery from deliberate acute carbon monoxide poisoning, the administration of electroconvulsive therapy was associated with a relapse, with subsequent neuropsychiatric impairment. It is suggested that, as electroconvulsive therapy could aggravate acute cerebral damage, its use during recovery from acute carbon monoxide poisoning should be abandoned.

Experimental diphtheritic neuropathy in the mouse: a study in cellular resistance.

Diphtheria toxin administered by direct intraneural injection procedures demyelination in the mouse sciatic nerve. A dose in the order of 2 million times greater on an equal weight of nerve basis to required to produce the lesion compared with the dose required in the chicken.

Visuo-motor skill and visual perception in left and right handed children of superior intelligence.

It was thought possible that the proximity of the right parietal cortex to the leading hand area in left handed subjects may confer an advantage in tasks requiring visuo-motor function. However, the study showed the left handed group to be defective in the performance of the Wechsler Block-design Sub-test. As some mature left handed individuals may excel in tasks requiring refined visuo-motor skill, it is suggested that any constitutional deficiency is not fixed, but may be expected to disappear with increased maturity, or as the result of training.

Sequelae to pneumoencephalography.

Fifty patients were examined clinically and neurologically for seven days after pneumoencephalography. Headache was present in 78%, neck stiffness in 34%, pyrexia in 38%, vomiting in 34%, tachycardia in 74%, a change in the level of consciousness in 18%, and abnormal neurological signs in 30%. Of the 13 patients with epilepsy, there was an increased frequency of seizures in four, associated with increased EEG epileptiform activity in three. EEG abnormality either appeared or increased in 74% of cases on the second day after the air study. A mechanism for the production of these sequelae is proposed. It is concluded that these findings indicate that in most cases an organic brain syndrome follows pneumoencephalography.