The refinement of retinotectal projection on tectal whole mount during the regeneration of the goldfish optic nerve labeled with DiI anterogradely

Radiographic computed tomography and magnetic resonance imaging are the procedures of choice in the diagnosis of patients with suspected pituitary gland abnormalities. Several cases are presented where the diagnostic value of such procedures in patients with diseases affecting the pituitary gland is demonstrated.     

Deformation twinning as a mode of energy accommodation

The conditions necessary for mechanical twin nucleation are considered. It is concluded that a high elastic strain energy accumulation must precede twin nucleation, and that twin formation provides an efficient means of excess energy accommodation. It is suggested that the significance of the resolved shear stresses present is limited to the slip deformation, which must precede, accompany, and follow twin formation in real crystals. The resultant shear deformation is not inherent in twinning itself, but originates in the associated slip. In the absence of slip, in a perfect crystal, twins can form by atom shuffles requiring no overall shear.     

Incomplete infarct and delayed neuronal death after transient middle cerebral artery occlusion in rats

BACKGROUND AND PURPOSE: The clinical syndrome of transient ischemic attacks is accompanied in a significant percentage of patients by brain lesions or neuroimaging abnormalities whose structural counterparts have not been defined. The objective of this study was to analyze, in an experimental model of short-term (< 25 minutes) focal ischemia and long-term (< or = 28 days) reperfusion, the extent and nature of the structural abnormalities affecting neurons and glia located within the territory of the transiently occluded artery. METHODS: Adult Wistar rats (n = 121) had the origin of one middle cerebral artery (MCA) occluded with a nylon monofilament for periods of 10 to 25 minutes. Experiments of transient MCA occlusion were terminated at variable periods ranging from 1 day to 4 weeks. Control experiments consisted of (1) MCA occlusion without reperfusion (n = 7) lasting 7 to 14 days and (2) sham operations (n = 2) followed by 1- to 4-day survival. After in situ fixation, brain specimens were serially sectioned and subjected to detailed morphometric evaluations utilizing light and electron microscopes. The statistical method used to evaluate the results was based on ANOVA followed by Bonferroni's corrected t test and Student's t test comparisons. RESULTS: Brain lesions were not detectable in the sham-operated controls. All brains with permanent MCA occlusion (7 to 14 days) had large infarctions with abundant macrophage infiltration and early cavitation. Forty-five (37%) of the experiments involving transient MCA occlusion had no detectable brain lesions after 4 weeks. Selective neuronal necrosis was found in 76 of 121 rats (63%) with transient MCA occlusion. Neuronal necrosis always involved the striatum, and in 29% of the brains with ischemic injury, necrosis also included a short segment of the cortex. In the striatum, the length of the arterial occlusion was the main determinant of the number of necrotic neurons (20 minutes [22.6 +/- 19] is worse than 10 minutes [4.9 +/- 7]) (P < .0001). In the cortex, the length of reperfusion determined the number of necrotic neurons appearing in layer 3. Experiments with reperfusion of 4 to 7 days' duration yielded more necrotic neurons per microscopic field (2.02 +/- 3) than those lasting fewer days (0.04 +/- 0.1) (P < .05). The histological features of these lesions underwent continuous change until the end of the fourth week, at which time necrotic neurons were still visible both in the striatum and in the cortex. CONCLUSIONS: Arterial occlusions of short duration (< 25 minutes) produced, in 76 of 121 experiments (63%), brain lesions characterized by selective neuronal necrosis and various glial responses (or incomplete infarction). This lesion is entirely different from the pannecrosis/cavitation typical of an infarction that appears 3 to 4 days after a prolonged arterial occlusion. Delayed neuronal necrosis, secondary to a transient arterial occlusion or increasing numbers of necrotic neurons in experiments with variable periods of reperfusion, was a response observed only at a predictable segment of the frontoparietal cortex.     

Integrated quantum well intersub-band photodetector and lightemitting diode

The authors propose and demonstrate the integration of a quantum well intersub-band photodetector (QWIP) and a light emitting diode (LED) for making large two-dimensional focal plane arrays for thermal imaging applications. The newly developed QWIP technology is combined with the well established LED technology both based on GaAs and related epitaxially grown alloys, such as AlGaAs and InGaAs     

Cysteine protease inhibitors block schistosome hemoglobin degradation in vitro and decrease worm burden and egg production in vivo

Schistosome parasites utilize hemoglobin as a major protein source for their metabolism. Degradation of hemoglobin has been hypothesized to be mediated by both cysteine and aspartyl proteases secreted into the lumen of the parasite intestine. We now show that two distinct types of irreversible cysteine protease-specific inhibitors both arrest schistosome hemoglobin degradation in vitro. Arrest of hemoglobin degradation is followed by death of developing schistosomula 1 week later. Schistosome infected mice treated by a dose of 2 mg inhibitor per day for 1 week early in infection, and 2 weeks at the time of egg production, showed a significant reduction in worm burden, hepatomegaly, and the number of eggs produced per female worm. Histopathology showed a minimal immune response to those eggs which were produced, consistent with a delay in egg production relative to untreated infections. By tagging the inhibitor with biotin, specific cysteine protease targets were identified in extracts of schistosome worms.     

Low-flow membrane oxygenation of blood in patients with diffuse purulent peritonitis

Small-flow membranous oxygenation of the blood was used in 45 patients with peritonitis in the multiple organ failure phase. In ten cases blood oxygenation was combined with hemofiltration. MOCT 19-03 (Kvant Research and Production Unit) and Gambro FH hemofilters (Sweden) were employed. Combination of small-flow membranous oxygenation of the blood combined with hemofiltration appreciably improved the oxygen-transporting function of the blood in adult patients with the respiratory distress syndrome, which was due to mutual potentiation of the two methods' effects. Small-flow membraneous oxygenation alone improved cellular immunity and decreased the laboratory manifestations of endogenous intoxication due to biotransformation of toxic products.     

Pixelless infrared imaging device

A new concept for infrared imaging using a pixelless photon frequency up-conversion device together with a CCD array is presented. The concept is applicable to wavelengths longer than the CCD response range (longer than about 1.1 μm). Preliminary imaging results using a quantum well infrared photodetector integrated with a light emitting diode are also presented     

On the nature of deformation of a crystalline solid: II. the absolute strain rate in elastic deformation

Elastic deformation process in a crystalline solid is consideredab initio in terms of an idealized model. It is shown that the apparent time invariance of strain in a semi-infinite solid deformed at a surface velocityv is the result of neglecting to take into account the discrete nature of the deformation process. An absolute strain rate, έ⁰ =v/d, whered is the interplanar spacing in the direction of deformation, can be rigorously derived. It is also shown that the same absolute deformation rate governs the deformation behavior in an infinite plate specimen, thus permitting unified treatment of infinite and finite length specimen deformation.