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A 67-year-old male patient with Waldenstrom's macroglobulinaemia associated with a sensorimotor polyneuropathy is reported. The progress of the disease was well controlled by Chlorambucil therapy. The sural nerve biopsy showed, in addition to loss of myelinated fibres an amorphous hyalin-like substance in the perineurium, endoneurium and the blood vessel walls which was strongly positive with the periodic acid-Schiff stain. Immunofluorescent study revealed that this substance contained IgM. Electron-microscopically this substance was shown to be osmiophilic and granulated. There was no deposit of amyloid in the sural nerve by Congo red and thioflavin T methods. However, cytoplasmic fibrils of about 80 A in thickness were present in the endothelia and pericytes. The pathogenesis of macroglobulinaemic polyneuropathy is discussed with special emphasis on a possible antibody activity of abnormal monoclonal IgM against the peripheral nervous system.

Zusammenfassung An 31 gesunden Versuchspersonen wurde die Impulsfortleitung frequenter Serienreize im gemischten N. ulnaris untersucht. Die Fortleitung des 2. und der weiteren Impulse einer Reizserie hangt bei hochfrequenter Reizung von der Dauer der absoluten Refraktarperiode ab. Die absolute Refraktarperiode betragt fur Fasern mit einer Leitgeschwindigkeit uber 50 m/sec 0.4 bis 0.7 msec. Bei niedrigen Reizfrequenzen bestimmt die relative Refraktarperiode die Art der Impulsubermittlung. Die Latenzverzogerung der nachfolgenden Potentiale setzt signifikant fruher, d.h. bei niedrigeren Reizfrequenzen, ein als die Amplitudenabnahme. Die Grenzfrequenz, bei der die Impulse noch unverandert fortgeleitet werden, liegt bei 350 cps.

The effects of the various geometrical factors of the X-ray optical system on intensity, peak-to-background ratio and resolution are derived and illustrated with experimental data. The arrangement of the specimen with respect to the X-ray tube and the optical system is shown to be a major factor in determining the intensity; and procedures for optimizing this source geometry in terms of the variation of intensity of primary radiation reaching the specimen, and self-absorption effects as a function of angle-of-view are outlined. The Soller collimator geometry is introduced with a discussion of the simple single crystal spectrometer and the effects of the angular and linear apertures in the equatorial and axial planes are explained. Various figures of merit are used to evaluate several geometries including the use of two Soller collimators. The minimum foil thickness, total reflection, the testing of Soller collimators, the elimination of spurious sources of background with antiscatter diaphragms and various other geometrical factors are discussed.