Search PubMed⌕ Search

Biomedical subjects

J Dobbing

Publications and source records attributed to J Dobbing.

At least 37 records · Page 2Linked to original sources
PubMed1980

A stereological analysis of the cerebellar granule and Purkinje cells of 30-day-old and adult rats undernourished during early postnatal life.

Male rats undernourished from birth to 30 days of age were nutritionally rehabilitated till 160 days of age. Quantitative stereological procedures at the light microscope level were used to estimate, among other things, the numerical densities of cerebellar granule and Purkinje cells on a "per unit volume of cortex" basis. These were subsequently used to calculate granule-to-Purkinje cell ratios. The 30-day-old undernourished rats had a mean +/- S.E. of 290 +/- 27 granule cells for every Purkinje cell present, compared to 395 +/- 34 for the controls. This was a deficit of about 27% (p < 0.05). At 160 days of age, the previously undernourished rats still showed a persisting deficit of about 25% (p < 0.05) in this ratio, despite the lengthy nutritional rehabilitation. There were no statistically significant age-related changes in this ratio. The numerical density of Purkinje cells, but not that of granule cells, was significantly greater in the previously undernourished rats than in controls, for both age groups, Increasing age caused a fall in the numerical density of both cell types. Granule and Purkinje cell nuclear diameters were unaffected by nutrition. However, Purkinje cell nuclei decreased in size by between 7%--13% with increasing age. These results indicate that undernutrition during early life can cause a permanent distortion of the relative number of the various cell types in the cerebellum.

Animals↗
PubMed1980

Synapse-to-neuron ratios of the frontal and cerebellar cortex of 30-day-old and adult rats undernourished during early postnatal life.

Male rats undernourished from birth to 30 days were nutritionally rehabilitated till 160 days of age. Quantitative stereological procedures at the light and electron microscopical levels were employed to estimate, among other things, the synapse-to-neuron ratios in the frontal cortex and granular layer of the cerebellum. In the frontal cortex, the 30-day-old undernourished rat had a mean +/- SE of about 14,020 +/- 1,540 synapses-per-neuron compared with 22,270 +/- 3,250 for the controls. This was a deficit of 37% (p < 0.05). By 160 days of age the previously undernourished rats showed no statistically significant deficit in this ratio compared with controls (11,800 +/- 690 and 13,360 +/- 1,110 respectively, p > 0.1). This was due mainly to a fall in the synapse-to-neuron ratio with age. A much larger fall in the ratio occurred in the control than in the previously undernourished group. In the granular layer of the cerebellum the 30-day-old undernourished rats had 341 +/- 17 synapses-per-neuron compared with 495 +/- 25 for the controls. This was a deficit of 31% (p < 0.01). By 160 days of age the previously undernourished rats again showed no statistically significant deficit in this ratio compared with controls (627 +/- 56 and 688 +/- 38, respectively (p > 0.1). These results show that the previously undernourished rats are capable of at least some (if not complete) "catch-up" with regard to the synapse-to-neuron ratio.

Animals↗
PubMed1979

Cell number and cell size: organ growth and development and the control of catch-up growth in rats.

One of the most important hypotheses for the control of catch-up after nutritional growth restriction relates developmental vulnerability to an early phase of cell multiplication, rather than to a later phase of growth of cell size. A re-examination of growing tissues, however, does not show the expected sequence of growth events, and the former hypothesis is therefore not supported.

Aging↗
PubMed1979

Fetal damage despite low-phenylalanine diet after conception in a phenylketonuric woman.

A woman with phenylketonuria gave birth to an infant with a cardiac defect and microcephaly despite introduction of a low-phenylalanine diet 5 weeks after conception (3 weeks after the first missed period). In maternal phenylketonuria fetal damage leading to reduced brain growth and cardiac malformations probably occurs within a few weeks of conception.

Abnormalities, Multiple↗
PubMed1979

A stereological analysis of the neuronal and synaptic content of the frontal and cerebellar cortex of weanling rats undernourished from birth.

The frontal cortex and granular layer of the cerebellum have been examined in 30-day-old rats undernourished from birth. Quantitative stereological procedures at the light microscopical level have been used to estimate the volume proportion and numerical densities of neuronal nuclei. Similar methods at the electron microscopical level were employed to calculate the numerical densities of synapses. Hence, synapse-to-neuron ratios have been calculated in these brain regions. In the frontal cortex, the undernourished group of rats showed a 37% deficit (P less than 0.05) in the synapse-to-neuron ratio. This was due to a combination of an increase in the numberical density of neurons and a decrease in the numerical density of synapses, although, individually, neither of these reached statistical significance at the 5% level. In the granular layer of the cerebellum there was a 31% (P less than 0.01) deficit in the synapse-to-neuron ratio. This was a function of the reduced numerical density of synapses, with no difference in the numerical density of granule cells between groups. For the frontal cortex, the volume proportion of neuronal nuclei was significantly greater in the undernourished group of rats. There were no significant differences between control and undernourished rats in the volume of the 'forebrain' occupied by cortex. The mean diameters of neuronal nuclei and synaptic discs did not differ in any given region between treatment groups. These observations are discussed in context with the previously published results on synapses and neurons in undernourished animals.

Animals↗
PubMed1979

Deciduous teeth contain histories of developmental disturbances.

The crowns of the deciduous teeth are permanent structures which form by incremental growth during the second half of pregnancy and first year of life. These structures become available between the ages of 6 and 12 years with normal exfoliation and can then be studied histologically to demonstrate evidence of metabolic disturbances occurring during tooth development. As the chronology of disturbances can be assessed with reasonable accuracy, such studies provide a potentially valuable research tool.

Female↗