Quantitative assessment of bone marrow hematopoiesis using parametric magnetic resonance imaging

Spatial maps of the percentage cellularity in pelvic bone marrow were calculated at a resolution of 15.6 mm3 from six volunteers and 10 patients treated for documented hematologic disease using a three-point Dixon MRI pulse sequence. The percentage cellularity calculation was aided by analyzing a two-dimensional feature space consisting of the apparent water fraction (Wa), and the T2 relaxation time of water (T2w). An extracellular water fraction was assigned to each voxel on the basis of a two-component T2w algorithm. In six cases, the method was compared to results obtained from core biopsies or aspirates of the posterior iliac crest. The results indicate that segmentation schemes that combine high-quality phase-contrast imaging with nuclear relaxation time measurements can potentially identify the true fractional marrow volume occupied by hematopoietic elements in a variety of clinical situations.     

Responses of ganglion cells to contrast steps in the light-adapted retina of the tiger salamander

PURPOSE: To evaluate the complications of laser-induced chorioretinal venous anastomosis in nonischemic central retinal vein occlusion (CRVO) and to identify the associated risks. METHODS: A retrospective consecutive series of 91 eyes (91 patients) with nonischemic CRVO with a mean +/- SD duration of 15.0 +/- 15.2 weeks (range, 3 to 72 weeks )and corrected visual acuity reduced to 20/100 or less because of perfused macular edema were reviewed. All eyes had one or more anastomotic attempts using argon laser (combined with Nd-YAG laser in 46 eyes) and a minimum of 12 months of follow-up. RESULTS: Successful chorioretinal venous anastomoses were created in 49 eyes (54%). Eighteen eyes (20%) had neovascular complications. These consisted of intravitreal, intraretinal, and subretinal neovascular membranes and were significantly associated with retinal ischemia (P < .001). There was avascular fibrous tissue proliferation at the anastomotic site in eight eyes (9%), and it was not associated with retinal ischemia (P = .727). No eye developed further capillary nonperfusion once an anastomosis became functional. A chorioretinal venous anastomosis was associated with improved vision (P < .001); 84% of eyes had an average +/- SD improvement of 4.3 +/- 3.8 lines (range, 2 to 20 lines), with the remaining 16% having no improvement or reduced vision. CONCLUSION: The major vision-threatening complication of laser-induced chorioretinal venous anastomosis for nonischemic CRVO is neovascular membranes occurring at the anastomotic site; these are associated with retinal ischemia. Prompt laser photocoagulation to areas of retinal ischemia that develop after the anastomotic attempt has been made may reduce the risk and severity of this complication.     

Peak temperatures of some prosthetic acrylates on polymerization

The aim of this study was to determine peak temperatures of some prosthetic acrylic resins at the time of polymerization. The acrylic resins included two temporary restoration resins, three autopolymerizing resins for different applications and one heat-cured denture base resin. The peak temperatures were measured with a ferro-constantan thermocouple from test specimens of three different volumes at different temperatures. The results revealed that with increasing volume of polymerizing acrylic resin the peak temperature also increased. In general, acrylic resins for temporary restorations had lower peak temperatures than other acrylic resins. However, despite the lower peak temperatures, the temperature of temporary restoration resins during polymerization can be as high as 82 degrees C. Therefore, to minimize thermal injuries of the tissues of vital tooth, dentists must be aware of the heat formation of the acrylic resins used in the oral cavity.     

Laboratory evaluation of the biocontrol potential of Mesocyclops thermocyclopoides (Copepoda: Cyclopidae) against mosquito larvae

Biocontrol potential of Mesocyclops thermocyclopoides against first instar larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus was studied under laboratory conditions. It was found that M. thermocyclopoides had the highest predation efficacy against Ae. aegypti followed by An. stephensi and Cx. quinquefasciatus. There was a significant reduction in the predation efficacy of M. thermocyclopoides against Cx. quinquefasciatus in the presence of alternate food (p < 0.01). The cage simulation trial indicated that M. themocyclopoides has the potential to control Ae. aegypti breeding effectively in a container type of habitat.