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Biomedical subjects

D J Morton

Publications and source records attributed to D J Morton.

7 recordsLinked to original sources

Pulsed static magnetic field effects on in-vitro pineal indoleamine metabolism.

In-vitro rat pineal glands stimulated with the beta-adrenergic receptor agonist isoproterenol to induce melatonin synthesis and exposed for 1 h to a pulsed 0.4-G static magnetic field demonstrated significant inhibition of serotonin-N-acetyltransferase activity and melatonin content. 2-h exposure to pulsed magnetic field also resulted in a significant reduction in isoproterenol-induced serotonin-N-acetyltransferase activity. These results support the idea that the cultured pineal gland can be affected directly by artificially generated weak magnetic fields.

Animals

Changes associated with glycolytic-enzyme binding in the equatorial X-ray-diffraction pattern of glycerinated rabbit psoas muscle.

The binding of fructose biphosphate aldolase to the thin filaments of glycerinated rabbit psoas muscle produces a significant change in its low-angle X-ray-diffraction pattern. The intensity of the (11) reflection relative to that of the (10) reflection increases by 26 +/- 3% (mean +/- S.E.M.), which is consistent with the increase in the mass of the thin filaments produced by enzyme binding. A similar effect is found with a mixture of aldolase and glyceraldehyde 3-phosphate dehydrogenase. The significance of the change in intensity is considered with reference to the interpretation of the equatorial patterns obtained from muscles in different physiological states. The magnitude of the increase in the relative intensity of the (11) reflection is lower than that observed between relaxed and contracting muscle and does not bring into question the interpretation linking changes in these patterns to cross-bridge movement. However, the effect due to enzyme binding may be important when making detailed interpretations of these changes. It may also be related to an unusual pattern sometimes observed in cardiac muscle.

Animals

Night calls in a group practice.

Night calls attended in 1977 by four doctors in a group practice were analysed and divided into categories of urgency.Slightly over half the night calls were genuine emergencies, and only four per cent were totally unnecessary.

Aged

The ward round.

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Consumer Behavior

An electron microscope study of the interaction between fructose diphosphate aldolase and actin-containing filaments.

The interaction of fructose diphosphate aldolase with F-actin, F-actin-tropomyosin, and F-actin-tropomyosin-troponin has been studied by using negative staining. In the absence of troponin, minor aggregates of aldolase and the F-actin filaments are formed. A well-ordered lattice structure is only formed in the case of the fully reconstituted filament when the filament-to-filament spacing is 18nm, and the cross-bridge spacing is 38.7 nm. Evidence is presented that the lattice is due to an interaction between troponin and aldolase. The minimum subunit structure of troponin, still capable of giving rise to a lattice, is the troponin-IT complex, which indicates that troponin-C is not involved in aldolase binding.

Actins

Analysis of interlibrary requests by hospital libraries for photocopied journal articles.

A study of the 1975 borrowing requests made by all hospital libraries in central western Massachusetts showed that there were 4,368 requests for articles contained in 1,071 different periodical titles. The numbers of requests per title ranged from eighty-nine for one title to one for each of 123 titles. A graph of the data showed a geometric progression, and the Bradford constants for this dispersion averaged 1.28. The percentage of total requests related to the age of requested issues varied from 62.48% for items not over five years old and 78.15% for issues not over ten years, to 95.57% for materials not over thirty years old. Bradford constants averaged 2.13. Of the thirty most requested periodical titles, sixteen were published in foreign countries, as follows: England--ten; Netherlands--three; Australia--one; Canada--one; and Sweden--one. The study's significance included its total coverage of a relatively large and isolated region, its focus upon the records of requesting rather than lending libraries, and its analysis of interlibrary rather than in-house activities.

Interlibrary Loans

Aldolase binding to actin-containing filaments. Formation of paracrystals.

Electron-microscopy observation show that when aldolase binds to F-actin or F-actin-tropomyosin, highly ordered paracrystalline structures are formed consisting of tightly packed filament bundles cross-banded at 36 nm intervals. Morphologically different paracrystalline arrays are formed between aldolase and F-actin-tropomyosin-troponin. The filament bundles are far more extensive and are characterized by a prominent cross-striation at 38nm intervals. It is suggested that this reflects an interaction between troponin and aldolase.

Actins