On the "specifics" of specific reading disability and specific language impairment.

The reading and oral language scores of 110 children with a specific reading disability (SRD) and 102 children with a specific language impairment (SLI) indicated that approximately 53% of children with an SRD and children with an SLI could be equally classified as having an SRD or an SLI, 55% of children with an SRD have impaired oral language, and 51% of children with an SLI have a reading disability. Finding that a large percentage of children can be equally classified as SRD or SLI has repercussions for the criteria used to define an SRD, for conceptualising subgroups of learning disability, and for estimates of the incidence of SRD. Further, it highlights the need for future studies to assess both the reading and oral language abilities of SRD and SLI participants to determine how specifically impaired and homogeneous samples really are.

Effects of a red background on magnocellular functioning in average and specifically disabled readers.

Two experiments were conducted using metacontrast masking to examine responses in the magno system of adults, average reading adolescents and adolescents with specific reading disability. In Experiment 1 the effects of a red background field on the metacontrast functions of adult subjects were investigated. Results showed that a red, compared to a photometrically matched white background field, significantly attenuated metacontrast magnitude, supporting the interpretation of metacontrast as due to magno system suppression of parvo system responses. The finding of a red background effect was replicated in Experiment 2 with the two adolescent groups. The metacontrast functions of the adolescent groups also differed significantly, with those with specific reading disability exhibiting weaker metacontrast than the average readers. This result is consistent with a deficit in the magno system of individuals with specific reading disability and indicates the continuation of the deficit beyond childhood.

Metabolism in the rat of a model xenobiotic plant metabolite S-benzyl-N-malonyl-L-cysteine.

1. The metabolism of a model xenobiotic plant metabolite S-benzyl-N-malonyl-L-cysteine (BMC) administered to rat at 10 mg/kg has been studied using a combination of radio-t.l.c. and h.p.l.c. 2. The major route of excretion for the administered 14C was via the urine (79% in 3 days). 3. The major metabolite was hippuric acid. The extent of biotransformation of BMC indicated the lability of the N-malonyl bond whose hydrolytic removal initiated a metabolic sequence which involved the action of C-S lyase to produce benzyl thiol. 4. A comparison of the findings from this study with those from experiments with N-acetyl-S-benzyl-L-cysteine and S-benzyl-L-cysteine is made to support the metabolic pathway proposed.

A comparison of the metabolic fate of phenol, phenyl glucoside and phenyl 6-O-malonyl-glucoside in the rat.

The metabolic fates of 14C-phenol and its model plant conjugates 14C-phenyl glucoside and 14C-phenyl 6-O-malonyl-glucoside have been compared following equimolar oral dosing to rats (1.2 mg phenol/kg). Rapid excretion of radioactivity in the urine (at least 80% within 24 h) was observed with each compound. Phenol was eliminated as expected mainly as phenyl sulphate (68%) and partly as phenyl glucuronide (12%). The excretion profile for phenyl malonyl-glucoside was very similar to that of phenol, with the exception that small amounts of phenyl glucoside and phenyl malonyl-glucoside were excreted. In contrast, a major part of the dose of phenyl glucoside was eliminated unchanged. The value of metabolism studies in the assessment of the toxicology of xenobiotic metabolites derived from plants is discussed.