Unsymmetric Dumbbell-Shaped Polyhedral Oligomeric Silsesquioxane (POSS) Compound as a Single-Component POSS Hybrid.

Dumbbell-shaped polyhedral oligomeric silsesquioxane (POSS) derivatives, in which two POSS units are linked through a bridge, have attracted attention in the last decade. Here, we prepared an unsymmetric dumbbell-shaped POSS derivative (3Ph-iBu) in which isobutyl- and phenyl-substituted POSS units are linked by a disiloxane unit and compared its thermal properties with those of the corresponding symmetric isobutyl- and phenyl-substituted dumbbell-shaped POSS derivatives (3iBu-iBu and 3Ph-Ph, respectively). The symmetric isobutyl- and phenyl-substituted dumbbell-shaped POSS derivatives, 3iBu-iBu and 3Ph-Ph, were almost completely phase-separated during a mixing process. This phase separation is due to the limited solubility of phenyl-substituted POSS compounds, which are only soluble in tetrahydrofuran (THF) and insoluble in hydrocarbons such as n-hexane and toluene, while the isobutyl-substituted POSS derivatives exhibit a wider spectrum of soluble solvents. The unsymmetric dumbbell-shaped POSS, 3Ph-iBu, showed hybrid properties of solubility in solvents and thermal behaviors. Differential scanning calorimetric (DSC) analysis showed that enthalpy of the phase transition of 3Ph-iBu was significantly lower than those of the mixture of 3iBu-iBu and 3Ph-Ph. No apparent melting behavior was observed above the phase transition. The thermal degradation of the weakest isobutyl substituents improves in the present single-component hybrid structure.

Urinary podocalyxin as a possible novel marker of intrauterine nephrogenesis and extrauterine podocyte injury.

BACKGROUND: The number of nephrons at birth is determined during fetal development and is modulated thereafter by postnatal podocyte injury. Hyperfiltration, caused by a reduced number of nephrons, is a risk factor for chronic kidney disease. It is therefore important to monitor the formation of nephrons. METHODS: Urine samples were collected from infants within 1-2 days of birth, with follow-up sampling for preterm infants at 37-39 weeks of corrected age. Urinary levels of podocalyxin (PCX), ß2-microglobulin (ß2MG), N-acetyl-ß-D-glucosaminidase (NAG), total protein (TP), microalbumin (mAlb) and creatinine were measured and the relationship between these markers evaluated. RESULTS: Seventy-nine neonates were enrolled in this study. Urinary levels of PCX at birth were higher than normal adult reference values, with levels increasing up to a gestational age of 36 weeks (p = 0.0242). At 37-39 weeks corrected age, urinary levels of PCX decreased to adult levels. The levels of PCX in the urine at birth were not correlated to urinary levels of ß2MG, NAG, TP and mAlb. CONCLUSIONS: An increased urinary level of PCX may be a marker of both active nephron formation and podocyte injury sustained at birth. As such, changes in urinary levels of PCX are likely to reflect adaptation of renal function to the extra-uterine environment.

The Usefulness of T1-Weighted Magnetic Resonance Images for Diagnosis of Acute Leukemia Manifesting Musculoskeletal Symptoms prior to Appearance of Peripheral Blood Abnormalities.

The patients with acute leukemia occasionally present with musculoskeletal symptoms initially, including bone pain, joint pain, muscular pain, and functional impairment. Without abnormal findings of peripheral blood cell counts or smear, the correct diagnosis tends to be delayed. Magnetic resonance imaging is often performed to examine musculoskeletal abnormalities; it can simultaneously reveal the bone marrow composition with high anatomical resolution and excellent soft tissue contrast. We present 4 pediatric patients who were initially diagnosed with acute pyogenic osteomyelitis or arthritis, based on the elevated white blood cell counts and/or C-reactive protein in addition to the localized high signal intensity on T2-weighted magnetic resonance images. Finally, they were diagnosed with B-cell precursor acute lymphoblastic leukemia by bone marrow examination. The period between the onset of musculoskeletal symptoms and the diagnosis of leukemia ranged from 20 days to 6 months. In all cases, the T1-weighted magnetic resonance images taken prior to detection of peripheral blood abnormality revealed diffuse low signal intensity of the bone marrow in regions adjacent or contralateral to localized musculoskeletal symptoms. These findings should raise the suspicion of leukemia even without abnormalities in peripheral blood.

Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri.

Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells.

Paroxysmal cold hemoglobinuria caused by an IgM-class Donath-Landsteiner antibody.

We report on a 4-year-old boy who developed paroxysmal cold hemoglobinuria (PCH) following the first dose of a seven-valent pneumococcal conjugate vaccine. He was admitted because of dark urine after exposure to cold air. Laboratory tests indicated anemia, increased serum indirect bilirubin and lactate dehydrogenase, and decreased serum haptoglobin. Donath-Landsteiner (D-L) test was positive. The D-L antibody belonged to the IgM class and exhibited anti-P specificity. Symptoms and signs subsided after supportive care without any medication. Although PCH is often associated with viral or bacterial infection and is caused by IgG-class D-L antibodies with anti-P specificity, this case was unique because a D-L antibody of the IgM class with anti-P specificity caused PCH after immunization with a pneumococcal vaccine.