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Biomedical subjects

A Oldfors

Publications and source records attributed to A Oldfors.

121 records · Page 7Linked to original sources
PubMed1980

Motor nerve conduction velocity and nerve fibre diameter in experimental protein deprivation. Studies on rat peripheral nerve during development.

Motor nerve conduction velocity (MCV) and nerve fibre calibre spectra of peripheral nerves were determined at different ages, during development in normal and protein-deprived rats. The protein deprivation was achieved by feeding female rats a protein deficient diet. Compared to control rats which were given a balanced diet, given ad lib from 2 weeks before conception and onwards. After weaning, the offspring were fed the same protein-deficient diet, the protein-deprived rats showed considerably reduced body weights but moderately reduced values of albumin and total protein in serum at 6 and 15 weeks of age. Although essentially the same, the mean nerve fibre diameter of the studied dorsal tail nerve was slightly larger in the protein-deprived rats at 6 weeks of age than in controls, while the inverse relationship was found at 15 weeks of age. The increase of MCV in normal and protein-deprived rats followed essentially the same curve during the period from 5-30 weeks of age. The results indicate that the MCV and nerve fibre diameter during development are correlated to chronological age and not to body size, although protein deprivation may, to a minor extent, influence nerve fibre calibre growth.

Animals↗
PubMed1980

Macrophages in peripheral nerves. An ultrastructural and enzyme histochemical study on rats.

The cellular content of the endoneurium in peripheral nerves of normal adult rats was studied. Endoneurial cells with high light-microscopical activity of acid phosphatase were usually located close to blood vessels or near the perineurium. Cells with the ultrastructural appearance of macrophages showed the same distribution and accounted for 2--4% of the endoneurial cell nuclei profiles. These cells rapidly endocytosed carbon particles after endoneurial administration of colloidal carbon in vitro.

Acid Phosphatase↗
PubMed1979

Barriers and transport properties of the perineurium. An ultrastructural study with 125I-labeled albuminin and horseradish peroxidase in normal and protein-deprived rats.

The permeability properties of the perineurium in sciatic nerves of 12-week-old rats were studied. The penetration of 125I-labeled albumin and horseradish peroxidase into the perineurium was investigated electronmicroscopically 10, 30, and 120 min after the local extraneural application of the tracers. The autoradiographic study included age-matched protein-deprived rats. It was concluded that the perineurium acted as a diffusion barrier but also permitted a slow passage of the macromolecules into the endoneurium. The result indicates that this penetration to some extent is due to vesicular transport across the perineurial cells. The significance of these barrier and transport properties of the perineurium is discussed. No obvious differences in perineurial permeability between normal and protein-deprived rats were obtained.

Animals↗
PubMed1979

Effects of local extraneural application of diphtheria toxin on the sciatic nerves of normal and protein deprived rats.

Diphtheria toxin was locally administered around the sciatic nerves of normal and protein deprived rats aged 3, 6, 12, and 26 weeks in order to investigate the permeability of the barriers enveloping the nerves. At all ages the rats developed a reversible hind limb paralysis linked to a severe segmental demyelination, indicating passage of the toxin into the endoneurium. From 6 weeks of age the pattern of reaction differed between the protein deprived and control rats. The differences are interpreted as being partly dependent on less efficient protective barriers of the sciatic nerves of the protein deprived rats.

Animals↗
PubMed1978

Barriers of peripheral nerve towards exogenous peroxidase in normal and protein deprived rats.

The protective barriers of the sciatic nerve in protein deprived and normal rats have been studied. Horseradish peroxidase (HRP) was applied extra-neurally in rats aged between 4 and 26 weeks. The spread of the tracer was investigated 2 h, 24 h, and 3 days after application. Passage of tracer into the endoneurium was found in all rats but decreased with age. Within the endoneurium, HRP was phagocytized by normally occurring endoneurial histiocytes, which constitute part of the protective barrier system of peripheral nerves. The functional development of the nerve protective barriers was retarded in protein deprived rats. Observations made in this study support the concept of a transperineurial vesicular transport of macromolecules.

Animals↗
PubMed1977

Paranodal myelin retraction in protein deficient and normal rats: a morphometric study.

Young rats, submitted to severe protein restriction were studied concerning the width of inter-myelin gaps at the nodes of Ranvier in peripheral nerve fibres. The results gave no proof of increased paranodal myelin retraction in lumbar spinal roots or the sciatic nerves of low-protein rats. Malnourished rats as well as controls showed great interindividual differences as to the presence of nodes with wide inter-myelin gaps.

Animals↗
PubMed1977

The effect of undernutrition on spinal ganglion nerve cell size. A morphometric study on rat.

In previous investigations on rat it has been shown that prenatally instituted undernutrition leads to an irreversibly impaired calibre growth in sensory fibres of the peripheral as well as the central nervous system. A study was made on the increase in size of spinal ganglion nerve cells of normal and undernourished rats. Although the undernourished rats weighted only 50% of the controls no differences in spinal ganglion nerve cell size were found in the four age groups examined, i.e. rats 20, 60, 90 and 180 days of age.

Animals↗
PubMedDate not supplied

Effects of training on skeletal muscle in protein-deprived rats.

The effects of exercise on atrophy of muscle fibres and loss of mitochondria in the extensor digitorum longus (EDL) and soleus muscles were studied in protein deprived rats. They had smaller muscle fibres than aged-matched control rats, the difference being more evident in type 2 than type 1 fibres both in the fast EDL and slow soleus muscles. The loss of weight was more pronounced in the EDL muscle which is composed mainly of type 2 fibres than in the soleus muscle which is composed mainly of type 1 fibres. Protein deprived rats subjected to a programme of periodic running on a treadmill for 12 weeks showed less muscle atrophy than sedentary, protein deprived rats. This effect of exercise in diminishing the degree of atrophy was more pronounced in the type 2 than type 1 fibres. The protein deprived rats which had been sedentary showed a marked loss of subsarcolemmal mitochondria, which was not seen in protein deprived rats undergoing exercise.

Adenosine Triphosphatases↗
PubMedDate not supplied

Rett syndrome: spinal cord neuropathology.

The morphologic changes of the spinal cord in Rett syndrome are described in 2 young women who died at 20 and 30 years of age. Both patients had been in a severely disabled state for many years with tetraparesis and extreme muscle wasting. Degeneration and loss of spinal ganglion nerve cells, in addition to gliosis of both the white and gray matter of the spinal cord, were evident. The number of motor neurons appeared to be reduced and axonal changes suggestive of degeneration were observed in both the ascending and descending tracts.

Adult↗
PubMedDate not supplied

Mitochondrial myopathy and cardiomyopathy in siblings.

Two siblings with infantile lactic acidosis and mitochondrial myopathy are described. The first child, a girl, died at 5 months of age from severe lactic acidosis after about 3 weeks of progressive muscular hypotonia. The younger brother had congenital lactic acidosis but no other symptoms until 6 months of age when progressive muscle weakness appeared. Treatment with dichloroacetate lowered the serum lactic acid level but did not affect his clinical condition. At 13 months of age, cardiomyopathy was diagnosed and he died at the age of 29 months of circulatory failure. Both children had mitochondrial myopathy. Postmortem examination of the boy revealed marked morphologic changes of the mitochondria in both skeletal muscle and the myocardium; biochemical investigation of skeletal muscle mitochondria demonstrated deficiencies in both complex I (NADH ferricyanide reductase) and complex IV (cytochrome c oxidase). The disease in these siblings differs in several respects from previously reported patients with mitochondrial myopathy and cytochrome c oxidase deficiency.

Acidosis, Lactic↗
PubMedDate not supplied

Rett syndrome: cerebellar pathology.

The cerebellar pathology at autopsy of 5 patients with Rett syndrome is described. The patients ranged in age from 7-30 years. All had markedly reduced brain weights with proportionately small cerebella. Microscopic examination revealed loss of Purkinje cells, atrophy, astrocytic gliosis of the molecular and granular cell layers, and gliosis and loss of myelin in the white matter. Cortical atrophy occurred focally along the folia and was often more marked in the tips of the folia. The 2 oldest patients had been treated with phenytoin which may have contributed to the morphologic changes. Atrophy and gliosis increased with age or in patients without phenytoin treatment; the youngest patient demonstrated only minor microscopic changes. In addition to the generalized alterations, 1 patient had several adjacent folia with severe atrophy. The results indicate that cerebellar changes in Rett syndrome consist of general hypoplasia with the addition of atrophy beginning in childhood and progressing over many years.

Adolescent↗
PubMedDate not supplied

The permeability of the basal lamina at the neuromuscular junction. An ultrastructural study of rat skeletal muscle using particulate tracers.

Various macromolecular substances, such as toxins and antibodies, may interfere with neuromuscular transmission. The neuromuscular junction is also known to be a site for the uptake of macromolecular substances into the axon for subsequent transport to the central nervous system. The synaptic cleft of the neuromuscular junction is separated from the rest of the extracellular compartment of muscle by the basal lamina, the permeability properties of which are not known. The penetration of macromolecular substances of varying size into the synaptic cleft of the neuromuscular junction has been studied in rats. Four different tracers: Imferon (an iron-dextran measuring 11 X 7 X 7 nm), ferritin (a spherical iron-protein 12 nm in diameter), Imposil (an iron-dextran measuring 21 X 12 X 12 nm) and colloidal gold-protein (20-25 nm in diameter) were injected into the palmaris longus muscle. Fifteen and 120 min after injection, the distribution of these particulate tracers was studied by electron microscopy. Imferon and ferritin penetrated rapidly through the basal lamina along the muscle fibres and also into the synaptic cleft of the neuromuscular junction. The larger Imposil and colloidal gold particles were restricted from penetrating the basal lamina even after 2 h, and these particles were traced only occasionally within the synaptic cleft. The results indicate that the basal lamina of muscle acts as a diffusion barrier to large macromolecules, preventing them from entering the synaptic cleft.

Animals↗