Hook wire localization of inferior lesions in the breast.

Inferior lesions in the breast can be difficult to localize pre-operatively using the hook wire technique as the equipment does not readily allow an approach from below. Distorting the breast by rolling it against the cassette holder displaces an inferior lesion into a lateral position. The lesion can then be easily localized by the shortest needle path.

Cerebral venous malformations.

Cerebral venous malformations (CVM) are increasingly being recognised with the widespread use of CT scanning. Five cases are presented which demonstrate typical angiographic features and CT findings. These lesions when located in the cerebral hemispheres are benign and have been distinguished from the better known arteriovenous malformations on the basis of their characteristic angiographic features. CT findings have been considered nonspecific but our early post contrast CT scans demonstrate characteristic features suggesting that in many cases the diagnosis of cerebral venous malformations may be made on the CT scan alone.

Warm fibers innervating palmar and digital skin of the monkey: responses to thermal stimuli.

1. Three hundred fourteen warm fibers innervating the glabrous skin of the monkey's hand were isolated by dissection in the median and ulnar nerves in two species, Macaca mulatta and M. nemestrina. Fiber samples in the two species were functionally similar and uniform in their properties. Their mean conduction velocity of 1.2 m/s (SD 0.5; n = 50) implies that these warm fibers were all unmyelinated. 2. A parametric study of the responses of warm fibers to near-rectangular warming and cooling pulses applied to glabrous skin was completed using 104 fibers. At a steady base-line skin temperature (T-base) of 34 degrees C all these warm fibers responded to warming pulses in the intensity range 0--8 degrees C with a simple, uniform discharge, which reached a peak rate of 1.5--4.0 s after the onset of stimulation; subsequent decay in this discharge rate had a time constant of 5--12 s and was virtually independent of the intensity of the warm pulse. The intensity function was linear for most fibers when the interstimulus interval was 60 s or longer. At a T-base of 29 degrees C, warm fibers were less responsive, but the temporal profile of the response was similar to that at a T-base of 34 degrees C in the intensity range 4--8 degrees C, and the intensity function was again linear. 3. At a T-base of 39 degrees C the intensity function of each warm fiber was complex. Most fibers responded briskly to warming pulses of 2--4 degrees C: the response to more intense warming pulses, particularly when the skin temperature rose above 45 degrees C, was structured and reproducible, but varied greatly among different fibers. With some the discharge evoked was of very high frequency for a few seconds, and then ceased. More than 80% of the sample of warm fibers did not discharge at all in response to warming pulses, which raised the skin temperature to 50 degrees C or above. 4. The responsiveness of warm fibers to warming pulses was dependent on previous stimulation when the interstimulus interval was less than 60 s. This temporal suppression was precisely structured and was examined quantitatively for trains of warming pulses, each lasting 4.0 s and presented every 10 s. The pattern of suppressive interaction was similar in form to that previously reported for cold fibers innervating palmar skin. 5. A quantitative study of the receptive fields of individual warm fibers demonstrated a spatiotemporal response pattern, which is best described in terms of a focal receptor zone less than 1 mm in diameter surrounded by thermally conducting skin. The skin's thermal conductivity is paramount in determining the warm-fiber's receptive-field characteristics. 6. The responses of warm fibers to cooling pulses and to warming ramps are described.

Mineralogical and petrological investigations of lunar samples.

Fragments of igneous rocks and breccias, and one coarse-grained rock with thin sections, have been studied. Minerals found include pyroxene, plagioclase, olivine, ilmenite, troilite, ulvöspinel, native iron, cristobalite, tridymite, alkali feldspar, apatite, and quartz. Textures are described and interpreted. Among features revealed by optical, microprobe, x-ray diffraction, and electron microscope methods are extreme zoning and unmixing in pyroxene grains, compositional variations in ilmenites, and effects of shock metamorphism. Some trace elements were determined by x-ray fluorescence analysis.