Pathology of skeletal muscle in mixed connective tissue disease

To characterize the pathology of muscle involvement in mixed connective tissue disease (MCTD), skeletal muscle biopsies from 13 patients with MCTD were examined by routine light microscopy, histochemistry, and direct immunofluorescence. The histologic and histochemical changes observed corresponded closely to changes seen in idiopathic polymyositis and the myopathy associated with systemic lupus erythematosus. Eight of 13 cases examined by direct immunofluorescence demonstrated immunoglobulin deposition either within normal appearing vessels, within normal fibers, around or on the sarcoplasmic membrane, or within the perimysial connective tissue. The histologic findings support Sharp's observation of the high incidence of focal inflammatory lesions in skeletal muscle biopsies of patients with MCTD. Immunoglobulin deposition in these muscle biopsies suggests an immunologic basis for the muscular symptomatology in MCTD.

Competency-based education

The essential elements of a P/CBDE program include the delineation of role-derived dietetic competencies, which are publicly stated in behavioral terms. The criteria used to measure the accomplishment of these competencies are criterion-referenced, and the student acquires the competencies at his own rate. Much confusion exists in differentiating between the essential characteristics and implementation modes. The use of modern technology and modular packaging of learning experiences does not automatically lead to a P/CBDE program. These are merely tools. The clear identification of competencies, objectives, and performance criteria are the essence of P/CBDE. Currently, dietetic educators are formulating competencies for their own programs. A national group of "experts" will need to be convened to develop competencies for the profession as a whole.

Inhibition of renal PGE2-9-ketoreductase by diuretics

The metabolism of PGE2 by extracts of renal cortex is species dependent. In the rat PGE2-15-hydroxydehydrogenase initiates metabolism whereas in the rabbit PGE2-9-ketoreductase predominates. In man both mechanisms may operate. Each of the metabolic enzymes, which limits the vasodilator-diuretic actions of PGE2, was inhibited by ethacrynic acid, furosemide and indomethacin. Some inhibition of PGE2-9-ketoreductase was also observed with chlorthalidone, hydralazine and phentolamine but the thiazide diuretics and a number of other cardiovascular-active agents were without significant effect. We conclude that the inhibition of PGE2-9-ketoreductase and PGE2-15-hydroxydehydrogeanse could contribute to the mechanism of action of the non-thiaxide diuretics in man.

Prostaglandin-E2-9-ketoreductase in rabbit kidney

The 100,000 xg supernatant of rabbit kidney contains a prostaglandin-E2-9-ketoreductase which has an obligatory requirement for NADPH. This enzyme is localised in the renal cortex and is able to quantitatively convert PGE2 to PGF2alpha. A broad pH profile was evident with an optimum at pH 7 with 5. Kinetic studies indicated a Km of 3 with 2 x 10-4M PGE2. The isoelectric point was at pH 5 with 65 and the molecular weight, as estimated by gel filtration, was 21,800. These values differ from those obtained with enzyme from monkey brain tissue and suggest a tissue specificity of PGE2-9-ketoreductase. By combining isoelectric focussing techniques with sephadex filtration considerable purification of the renal enzyme was achieved.

The dietitian and credentialing

The meaning and ramifications of credentialing and accreditation have direct and powerful implications for the professional dietitian. There is also intense interest on the part of the public, as it views each profession's role in providing health care, as to the quality and expense ot that care. Each dietitian's analysis of the direction our Association must take in accreditation and credentialing is mandatory to the growth of nutritional care and its responsiveness to the needs of the American people. Issues have been presented and reviewed in this article. Some proposals for change have been suggested. By no means is the issue of accreditation or credentialing static among the health professions. New studies are being started routinely. New ideas and issues are continually being proposed and analyzed. What is good today for the practitioner and the public may be non-functional tomorrow. However, it seems certain that changes are imminent. It is imperative that each member of The American Dietetic Association assume an active role in the decisions that will be made for the future of each of us.

Absolute measurement of structure factors using a new dynamical interference effect

A new method of determining X-ray scattering factors by dynamical interference is described. The theoretical background to the interference effect is discussed in detail and an expression for relating the fringe period to the structure factor is developed. The method relies on anomalous transmission and is therefore most suitable for measurements on nearly perfect crystals of high atomic weight. It also has the attractive property of being insensitive to slowly varying lattice strains. Applying the method to the 220 reflexion of silicon a value of 8.487 ± 0.017 for the atomic scattering factor has been obtained using Mo Kα 1 radiation. This value is in excellent agreement with the author's previous results using the Pendellösung method.