A specific activation of microglia was only found in patients in whom the PT was affected by the stroke and only caudal (anterograde) to the lesion; no activation was found in the retrograde direction or in those patients in whom the PT was not affected. These findings were independent of infarct size and may represent changes secondary to early Wallerian degeneration.

No abstract

No abstract

Current challenges facing us in developing dedicated position emission tomography (PET) system for metabolic breast mammography (PEM) and small animal (ANIPET) are to achieve high spatial resolution (less than 2 mm) and high efficiency. It is also crucial to extend the sensitive areas of PEM detectors to their periphery in order to overcome the difficulty in imaging near a patient's chest wall. This limitation of the periphery dead region was revealed in the clinical trials of our previously developed PEM-I system.In the new study, we developed prototype detectors by using position-sensitive photomultiplier tubes (PS-PMTs) and pixelated bismuth germanate (BGO) crystals with depth encoding scheme to detect and localize gamma rays. The procedures in crystal processing include cutting, polishing, encapsulating, separating, and re-gluing. We also developed front-end electronic circuits including high-voltage dividers, anode resistor chains, position readout circuits, and last dynode timing circuits. Methods for combining four PS-PMTs with simple X+, X , Y+, Y outputs have been developed to further simplify the position recording. The detectors were constructed in the structure of array (two in the system)-module (four in each array)-unit (four in each module). The basic unit of one crystal and one PS-PMT can be field replaceable.Our new prototype detectors show that the proposed PEM-II system has a spatial resolution of 1.8 mm (versus 2.8 mm in PEM-I), a timing resolution of 10.3 ns (versus 12 ns in PEM-I), and a field-of-view of 88 mm 88 mm (versus 64 mm 56 mm in PEM-I). Compared with our previous PEM-I system, it demonstrates that the design improves the spatial resolution, enhances the detector field-of-view, and significantly reduces the peripheral dead regions. Index Terms-Bismuth germanate (BGO) crystal, position-sensitive photomultiplier tube (PS-PMT), positron emission mammography (PEM), positron emission tomography (PET).

No abstract

I t has been well established through the use of tracers that tryptophan, an essential amino acid, is a necessary precursor of serotonin for animals ( 1). The variation of brain serotonin level with the level of tryptophan in the diet has been demonstrated several times. For instance, brain serotonin level increases substantially when tryptophan supplements are added to diets(2,3) and, conversely, a 37% decrease in brain serotonin was noted after rats had been fed a tryptophan deficient diet for over 4 weeks(4). Other@) demonstrated a decrease of approximately 65% after 5-6 weeks on a tryptophan deficient diet. However, Green et al.( 2 ) found no significant decrease in brain serotonin of young white rats placed on a tryptophan low diet for 14 to 17 days. These previous studies have not included measurements of brain serotonin level as a function of time on a tryptophan deficient diet. Also the change in plasma tryptophan level with respect to brain serotonin level has not been explored. These two points are the basis for this investigation.Methods and materials. One hundred and eight female Wistar rats weighing approximately 165 g each were divided into 2 groups. One group received a .5% L-tryptophan supplement in the diet and the other received the unsupplemented diet, the composition of which was as follows: acid-hydrolyzed casein, salt free powder (NBCo.)-20% ; glucose-47.7% ; cornstarch-20% ; celluflour-2 % ; salt mix, U.S.P. XIV-S% ; DL-methionine-.3 % ; Wesson oil-5 % . The following amounts of vitamins were added to 8 kg of this feed: thiamin hydrochloride -80 mg; riboflavin-80 mg; pyridoxine hydrochloride-80 mg ; choline chloride-1 6 g ; -~

No abstract

No abstract