The Inter-relationship of Mental Capacity, Physique, and Home Environment of School Children

The children included in the Investigation were 479 boys and 476 girls of approximately nine years of age and 346 boys and 337 girls of approximately thirteen years of age. Irregularity of attendance caused retardation in school especially in the case of boys, and was most marked among professional workers' children and children from overcrowded houses. Owing to this irregularity a child's position in school could not be taken alone as an index of its mental capacity. Children from smaller sized or overcrowded houses, largely inhabited by manual workers, were frequently dirty and poorly clad, and were in marked excess in the retarded divisions, while children who were clean and had good clothing preponderated in the advanced division. The retardation might be negatived to a certain extent by the earlier age of entry to school of children of this type. The active factor appeared to be the poorer nutrition. There was a larger percentage of manual workers' children in the lower mental capacity divisions, while an increased proportion of children of sedentary workers were advanced pupils and the children of professional men clustered round the normal and retarded divisions. There was a marked tendency for girls to find their way into relatively more advanced classes than boys. There was a steady decline in nutrition with descending mental capacity, except in the XIII. years group advanced division, where the girls were not increased in height and weight over their fellows. Children of sedentary workers were taller and heavier than children of manual workers but smaller and lighter than those of professional workers, i.e., height and weight figures varied according to the number of apartments in the home, or, more exactly the degree of overcrowding. Irregular attenders, children with physical defect, and children employed out of school hours, were as well nourished as their fellows. Maternal efficiency, income per person, nutrition of the child, and milk consumption varied directly with each other and inversely with overcrowding. The proportion of income spent in rent and taxes varied directly with maternal efficiency and nutrition but inversely with overcrowding and income per person. Maternal efficiency appeared to be more closely allied to the physical and hence the mental welfare of the children than any of the other factors investigated. Physical defect was more marked in manual than in sedentary and in sedentary than in professional workers' children. While one physical defect as a rule was insufficient to cause retardation, the combined action of several might do so. Children suffering from defective vision (uncorrected) were retarded in school. Enlargement of tonsils and anaemia or functional cardiac defect apparently did not affect the position in school. It did not appear that transferring children from slum areas to good housing conditions did in itself improve their physical development. Employment out of school hours did not cause retardation, though it reduced the numbers of hours in bed per night. With regular attenders, grouping according to mental capacity was the same as grouping according to intelligence. These general results cannot be applied to individual cases

Physiological studies on the postsynaptic dorsal column system

This thesis has made an electrophysiological study of segmental and descending influences on identified neurones of the postsynaptic dorsal column (p.s.d.c.) system and has examined aspects of the relationship between the neurones of this projection and the spinocervical tract (s.c.t.). Extracellular single unit microelectrode recordings were made from the axons of p.s.d.c. neurones ascending the dorsal columns of cats anaesthetised with chloralose.1) The response properties and organisation of the cutaneous receptive fields of p.s.d.c. neurones were investigated using light tactile, and noxious mechanical and thermal stimuli.The receptive fields of units with input from glabrous skin had a complex organisation and many were discontinuous. These units could be inhibited by both light tactile and noxious cutaneous stimuli. In contrast, units with receptive fields confined to hairy skin of the proximal limb often had a concentric receptive field organisation in which the high threshold excitatory component extended beyond the low threshold area. These units could be inhibited only by light tactile stimuli and their inhibitory receptive fields generally covered an extensive area of skin virtually surrounding the excitatory componentsThese observations are contrasted with the (ii) relatively simple receptive field organisation of s.c.t. neurones and are discussed in relation to previous observations of the morphology and ultrastructure of neurones of the p.s.d.c. and s.c.t. systems.2) A study has been made of the influence of systems descending from the brain on the response properties and receptive field organisation of p.s.d.c. neurones. The cutaneous receptive fields of p.s.d.c. units were investigated both before and during a block of conduction in descending fibres produced by cooling a region of cord rostral to the recording site. The results indicate that both the responsiveness of p.s.d.c. neurones to noxious mechanical and thermal stimuli and the area of skin from which such stimuli may effectively excite these cells are powerfully suppressed by inhibitory controls descending from the brain. The possible functions of these descending actions are discussed.3) The relationship between neurones of the p.s.d.c. and s.c.t. systems has been investigated. Contrary to recent reports in the literature, it was established that p.s.d.c. and s.c.t. projections arise in substantial part, if not entirely, from separate populations of neurones in the dorsal horn. There is, however, a close relationship between the two systems at the level of the dorsal horn. Evidence was obtained to support the suggestion that some s.c.t. cells make effective excitatory collateral connections with p.s.d.c. neurones

Monitoring the Performance of Educational Programmes in Developing Countries

Teaching/Communication/Extension/Profession,

Toad atrial natriuretic peptide : cDNA cloning and functional analysis in isolated perfused kidneys

Complementary DNA (cDNA) encoding Bufo marinus (toad) preproatrial natriuretic peptide (preproANP) was isolated by reverse-transcription polymerase chain reaction. Sequence analysis of toad preproANP cDNA revealed an open reading frame of 150 amino acid residues, which shared 72% and 66% identity with Rana catesbeiana and Xenopus laevis preproANP, respectively. The deduced amino acid sequence of toad ANP that corresponded to ANP 1&ndash;24 of R. catesbeiana and Rana ridibunda was identical, but it differed by four residues from that of X. laevis. ANP mRNA transcripts were also shown to be expressed in the toad kidney. Subsequently, the effect of frog ANP (1&ndash;24) on renal function in toad was examined using a perfused kidney preparation. The arterial infusion of frog ANP caused a dose-dependent decrease in the arterial perfusion pressure that was associated with an increase in the glomerular filtration rate (GFR) and a renal natriuresis and diuresis. The renal natriuresis and diuresis resulted predominantly from an increased GFR rather than from direct tubular effects. This study demonstrates that ANP can regulate renal function, which suggests it may be involved in overall fluid volume regulation.<br /

Human olfactory mesenchymal stromal cell transplants promote remyelination and earlier improvement in gait co-ordination after spinal cord injury

Autologous cell transplantation is a promising strategy for repair of the injured spinal cord. Here we have studied the repair potential of mesenchymal stromal cells isolated from the human olfactory mucosa after transplantation into a rodent model of incomplete spinal cord injury. Investigation of peripheral type remyelination at the injury site using immunocytochemistry for P0, showed a more extensive distribution in transplanted compared with control animals. In addition to the typical distribution in the dorsal columns (common to all animals), in transplanted animals only, P0 immunolabelling was consistently detected in white matter lateral and ventral to the injury site. Transplanted animals also showed reduced cavitation. Several functional outcome measures including end-point electrophysiological testing of dorsal column conduction and weekly behavioural testing of BBB, weight bearing and pain, showed no difference between transplanted and control animals. However, gait analysis revealed an earlier recovery of co-ordination between forelimb and hindlimb stepping in transplanted animals. This improvement in gait may be associated with the enhanced myelination in ventral and lateral white matter, where fibre tracts important for locomotion reside. Autologous transplantation of mesenchymal stromal cells from the olfactory mucosa may therefore be therapeutically beneficial in the treatment of spinal cord injury

Gait analysis in a <i>Mecp2</i> knockout mouse model of Rett syndrome reveals early-onset and progressive motor deficits

Rett syndrome (RTT) is a genetic disorder characterized by a range of features including cognitive impairment, gait abnormalities and a reduction in purposeful hand skills. Mice harbouring knockout mutations in the &lt;i&gt;Mecp2&lt;/i&gt; gene display many RTT-like characteristics and are central to efforts to find novel therapies for the disorder. As hand stereotypies and gait abnormalities constitute major diagnostic criteria in RTT, it is clear that motor and gait-related phenotypes will be of importance in assessing preclinical therapeutic outcomes. We therefore aimed to assess gait properties over the prodromal phase in a functional knockout mouse model of RTT. In male &lt;i&gt;Mecp2&lt;/i&gt; knockout mice, we observed alterations in stride, coordination and balance parameters at 4 weeks of age, before the onset of other overt phenotypic changes as revealed by observational scoring. These data suggest that gait measures may be used as a robust and early marker of &lt;i&gt;Mecp2&lt;/i&gt;-dysfunction in future preclinical therapeutic studies

The effects of partial prestressing on newly cast Haydite beams

Call number: LD2668 .T4 1955 R54Master of Scienc

Crack Growth Induced by Sonic IR Inspection

We have developed an experiment to study the propagation of laboratory-synthesized fatigue cracks under various controlled conditions during Sonic IR inspection. The experiment provides for good repeatability in testing. The parameters of interest include the initial crack length, load history (stress intensity and load ratio) during crack generation, geometry of the crack, material and also the various conditions involving the ultrasonic excitation source. In general, we find that under typical sonic IR inspection conditions, the initial crack will propagate under sonic IR testing. The crack growth after each inspection event varies and exhibits a distribution in length of propagation. The results show that the average crack propagation decreases with increasing stress intensity factor, and we test two hypotheses about the cause of this. Furthermore, we find that crack propagation is affected by the initial crack length