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Biomedical subjects

D A Winfield

Publications and source records attributed to D A Winfield.

At least 73 records · Page 4Linked to original sources
PubMed1980

An electron-microscopical study of the postnatal development of the lateral geniculate nucleus in the normal kitten and after eyelid suture.

The postnatal development of the lateral geniculate nucleus has been studied qualitatively with the electron microscope in normal kittens and in kittens with unilateral or bilateral eyelid closure. From birth to about 20 days there is relatively little development and the ultrastructural features characteristic of the adult cat, especially the synaptic organization of glomeruli, are mainly acquired between 40 and 55 days, when there is a rapid increase in the level of maturity. Unilateral and bilateral eyelid suture have virtually no effect upon the normal development, but some neurons in the deprived laminae have slightly less granular endoplasmic reticulum.

Age Factors↗
PubMed1980

A quantitative electron-microscopical study of the postnatal development of the lateral geniculate nucleus in normal kittens and in kittens with eyelid suture.

The postnatal development of the lateral geniculate nucleus has been studied quantitatively with the electron microscope in normal kittens and in kittens with eyelid closure. The maturation of the synaptic organization of glomeruli in the normal kitten occurs during the period of susceptibility to eyelid closure and is due predominantly to a logarithmic increase in the number of symmetric presynaptic dendritic synapses. In contrast, the proportion of symmetric synapses falls with age in non-glomerular neuropil over this period. Unilateral and bilateral eyelid suture do not interfere with the normal development of the lateral geniculate nucleus.

Age Factors↗
PubMed1980

The synaptic organization of glomeruli in the magnocellular and parvocellular laminae of the lateral geniculate nucleus in the monkey.

The synaptic organization of glomeruli in the magnocellular laminae of the lateral geniculate nucleus in the macaque monkey has been compared quantitatively with that of glomeruli in the parvocellular laminae using a sampling technique based on single sections. It was found that retinal boutons establish comparable total numbers of synapses in glomeruli in single sections in all laminae, but a relatively higher proportion of them are upon presynaptic dendrites in the magnocellular laminae. In addition, more synaptic contacts are made by presynaptic dendrites in the magnocellular laminae, and consequently in a given section glomeruli in these laminae have on average more synapses in them. Neuronal somata in the magnocellular and parvocellular laminae were studied with the light- and electron-microscopes and there were no complex laminated bodies encountered.

Animals↗
PubMed1980

An electron microscopic study of the types and proportions of neurons in the cortex of the motor and visual areas of the cat and rat.

The neuronal cell somata in the cortex of the motor and visual areas of the cat and rat have been studied with the electron microscope. It has been possible to recognize the cell types which have been identified in the corresponding functional areas of the cortex of the monkey: pyramidal, large and small non-pyramidal. The large non-pyramidal or stellate cell has abundant endoplasmic reticulum and mitochondria and receives numerous asymmetric and symmetric synapses; the small non-pyramidal or stellate has a small amount of cytoplasm and few synapses of both asymmetric and symmetric nature. The proportions of these types of neurons are of the same order of magnitude in the different functional areas and in the different species: approximately two-thirds are pyramidal, slightly less than one-third are small stellate, and less than 10 per cent are large stellate. There is the same mean number of synapses upon the pyramidal and small stellate cell in the visual and motor areas of the rat and cat, but this number is less in the monkey being 50 per cent less in the visual cortex and 25 per cent less in the motor area.

Animals↗
PubMed1979

An electron microscopic study of neurones in the lateral geniculate nucleus of the monkey labelled by retrograde transport of horseradish peroxidase.

In a previous report horseradish peroxidase (HRP) reaction product has been described as accumulating in a restricted part of neurones in the lateral geniculate nucleus following injections of HRP into the visual cortex of the primate. With the aid of long series of ultrathin sections from the same material labelled neurones have been partially reconstructed in the present study, and it has been confirmed that HRP reaction product aggregates as a group of electron-dense lysosome-like bodies which form a cap to one side of the nucleus.

Animals↗
PubMed1978

Cellular hyperviscosity as a cause of neurological symptoms in leukaemia.

Six patients with various forms of leukaemia had neurological signs and symptoms associated with an extremely high white blood cell count and increased whole blood (but not plasma) viscosity. All were treated by leucapheresis with an Aminco Celltrifuge. Rapid and complete reversal of all symptoms occurred in three patients and partial recovery in one. One patient died shortly after leucapheresis and another (from cerebral intravascular coagulation) two days later. It is concluded that a cellular hyperviscosity syndrome may cause neurological dysfunction in patients with extremely high white cell counts, and that leucapheresis, in carefully selected patients, can be an effective method of treatment.

Adult↗
PubMed1978

Myelomatosis and the hyperviscosity syndrome.

Eleven patients are described in whom myelomatosis was complicated by the laboratory and clinical features of the hyperviscosity syndrome (HVS). The myeloma type was IgA in nine and IgG3 in two. In those patients with IgA myeloma the HVS was related to the presence of high molecular weight complexes in the serum. Remission of clinical features was obtained in all patients by plasma exchange. Clinical improvement coincided with reduction of whole blood viscosity and in those patients with IgA myeloma, with a parallel reduction of the high molecular weight complexes. The relationship between the IgA complexes and blood viscosity has been examined by physicochemical analysis of purified IgA monomer and polymers and evidence is presented to show that the IgA polymer has a higher intrinsic viscosity and axial ratio than the larger IgM molecule. The significance of these observations is discussed.

Blood Viscosity↗
PubMed1976

The termination of thalamo-cortical fibres in the visual cortex of the cat.

An electron microscopic study has been made of the site and mode of termination of thalamo-cortical fibres in area 17 of the visual cortex of the cat. Thalamo-cortical fibres had been selectively interrupted 4-5 days before perfusion of the brain. In agreement with previous studies, degenerating axon terminals were found in layer I, in the deep part of layer III, and in layer IV of the cortex. In addition, a few degenerating thalamo-cortical axon terminals were found making synapses upon spines and small dendrites in layer VI. Two examples were seen of degenerating axon terminals making axo-dendritic synapses upon dendrites in continuity with their cell bodies. These neurons were not large stellate cells and were probably pyramidal.

Animals↗
PubMed1975

Serial changes in the coagulation system following clotting factor concentrate infusion.

Various parameters of the coagulation system have been monitored in patients with Christmas disease following the infusion of clotting factor concentrates. Significant reduction of clotting factor VIII and serum antithrombin III were observed in each of the five studies, whilst the plasma fibrinogen level fell in four subjects. The induced abnormalities were shortlived and there were no clinical sequelae. Further studies are required to assess the effects of similar concentrates in patients with liver disease.

Antithrombins↗
PubMed1974

Essential thrombocythaemia and peripheral gangrene.

Six patients are described in whom gangrene of one or more toes occurred as the presenting feature of essential thrombocythaemia. Spontaneous platelet aggregation was observed in platelet-rich plasma from four patients and platelet aggregation after the addition of adenosine diphosphate and collagen was highly abnormal in samples from all six. All of the patients described dramatic relief of pain within six hours of ingestion of aspirin and this coincided with disappearance of the spontaneous platelet aggregation and collagen-induced platelet aggregation. Treatment with phosphorus-32 corrected the platelet count and there were no further recurrences of peripheral vascular disease. Platelet function tests performed at the time all gave normal results. It is concluded that essential thrombocythaemia is an important and treatable cause of peripheral vascular disease.

Adenosine Diphosphate↗