Pathways involved in the evolution of leukemic stem cells.

Understanding the evolution of the cancer cell from a normal cell holds the key to developing novel, potent therapies against cancer. Two hypotheses describing the origins of cancer cells have been developed: one stating that any normal cell can acquire the ability to replicate indefinitely and evade natural cell death signals by accumulating multiple mutations over time, and a second suggesting that adult stem cells, by virtue of their pre-existing capacity for differentiation, asymmetric division and self-renewal, are the more likely targets of carcinogenic mutation. The leukemic stem cell (LSC) was the first cancer stem cell described. Evolving from the aberrant regulation and mutation of hematopoietic stem cells (HSCs), LSCs are suggested to encompass the subset of tumor cells sufficient for continued tumorigenesis. LSCs were also found to differentiate into a variety of cancer cell progenitors in a manner reminiscent of HSC differentiation, also explaining the observed heterogeneity of leukemic cells. How these cells form from HSCs remains to be fully comprehended. However, over recent years, marked progress has been made in contributing to our knowledge of cancer stem cells and what signaling cascades are involved in their development. Therapeutics targeting the pathways allowing for LSCs to sustain proliferation and self-renewal may prove to be more effective treatments for lymphoblastic leukemia.

Development of a new model of transvenous thrombosis in the pig superior sagittal sinus using thrombin injection and balloon occlusion.

PURPOSE: To establish an experimental model of superior sagittal sinus (SSS) thrombosis using a transvenous route, and thrombin and balloon occlusion, in pigs. METHODS: The SSS was catheterized transvenously in six pigs. Thrombin was injected into the pigs' SSS to induce thrombosis. Magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) confirmed successful SSS thrombosis. MRI and MRV were also used to observe the evolution of thrombus and accompanying brain parenchymal changes before thrombus induction postoperatively on Days 1, 3, and 7. The pigs were sacrificed for histological examination at the follow-up. RESULTS: SSS thrombosis was successfully achieved in all six pigs. On Day 1 postoperatively, MRV confirmed SSS thrombosis and MRI revealed brain edema in each animal. On Day 3, venous infarction was noted in two cases, one of which appeared to be hemorrhagic. On Day 7, MRV showed partial recanalization of the SSS in one pig. Brain edema was significantly relieved in four cases while, in two other cases, the extent of venous infarction was reduced. Histological examination confirmed SSS thrombosis in all animals, with recanalization in only one case. In two of the animals, bilateral parasagittal infarction was seen, including one with petechial hemorrhage. In the other four animals, bilateral parasagittal edema was observed. CONCLUSION: The development of an experimental model of SSS via the transvenous route is feasible in pigs using thrombin and balloon occlusion. This model closely resembles SSS thrombosis in humans, and can be applied in the clinical study of this phenomenon as well as in clinical therapeutic applications.

Optimization of pressurized liquid extraction for Z-ligustilide, Z-butylidenephthalide and ferulic acid in Angelica sinensis.

Pressurized liquid extraction, one of the most promising and recent sample preparation techniques, offers the advantages of reducing solvent consumption and allowing for automated sample handling. It is being exploited in diverse areas because of its distinct advantages. However, because the extraction is performed at elevated temperatures using PLE, thermal degradation could be a concern. Z-ligustilide, one of the biologically active components in Angelica sinensis, is an unstable compound, which decomposes rapidly at high temperature. In this study, we carried out a comparative study to evaluate PLE as a possible alternative to current extraction methods like Soxhlet and sonication for simultaneous extraction of Z-ligustilide, Z-butylidenephthalide and ferulic acid in A. sinensis. The operating parameters for PLE including extraction solvent, particle size, pressure, temperature, static extraction time, flush volume and numbers of extraction were optimized by using univariate approach coupled with central composite design (CCD) in order to obtain the highest extraction efficiency. Determination of Z-ligustilide, Z-butylidenephthalide and ferulic acid were carried out by means of high performance liquid chromatography with diode-array detector. The results showed that PLE was a simple, high efficient and automated method with lower solvent consumption compared to conventional extraction methods such as Soxhlet and sonication. PLE could be used for simultaneous extraction of Z-ligustilide, Z-butylidenephthalide and ferulic acid in A. sinensis.

[Determination of naoning pian by multi-wavelength linear regression method].

Assay of naoning pian was reported by multi-wavelength linear regression method in this paper. The program was edited by BASIC. The recoveries and RSD of pyramidon and caffeine were 98.03%-100.9%, 1.0% and 97.77%-99.39%, 0.61%, respectively. This method could be used for the determination of two components in naoning pian without separation. The method was simple, rapid, and results were satisfactory.

Accuracy of birth certificate data regarding the amount, timing, and adequacy of prenatal care using prenatal clinic medical records as referents.

This study compared birth certificate data on the amount, timing, and adequacy of prenatal care with the same data abstracted from the prenatal clinic records of 2,032 women who attended a health department prenatal clinic in northeast Georgia from 1980 to 1988. Overall accuracy was poor. Only 14.3% (n = 291) of the records completely agreed on the total number of visits, while approximately 36% (n = 738) and 53% (n = 1,081) agreed within one visit and two visits, respectively. Complete agreement for month and trimester prenatal care began was 31.1% (n = 632) and 50.6% (n = 1,202), respectively. Because of the small geographic region included in the current study, the generalizability of these findings to other populations may be limited.

Proportionate mortality study of golf course superintendents.

A proportionate mortality study of a cohort of golf course superintendents was conducted using death certificates for 686 deceased members of the Golf Course Superintendents Association of America who died from 1970 to 1992. White males were included in the study population from all 50 states. The study objective was to compare mortality from this cohort to the general U.S. white male population. The proportionate mortality ratio (PMR) for all types of cancer was 136 (CI: 121, 152). Significant excess mortality from smoking-related diseases was observed. The PMR for arteriosclerotic heart disease was 140, which was significantly elevated (CI: 127, 155). In addition, the PMR for all respiratory diseases was 176 (CI: 135,230), while the PMR for emphysema was 186 (CI: 101,342). The PMR for lung cancer was 117 (CI: 93, 148). Mortality for four cancer types--brain, lymphoma (non-Hodgkin's lymphoma, NHL), prostate, and large intestine--occurred at elevated levels within this cohort: brain cancer PMR = 234 (CI: 121,454), non-Hodgkin's lymphoma (NHL) PMR = 237 (CI: 137,410), prostate cancer PMR = 293 (CI: 187,460), and large intestine cancer PMR = 175 (CI: 125,245). The PMR for diseases of the nervous system was 202 (CI: 123,333). A similar pattern of elevated NHL, brain, and prostate cancer mortality along with excess deaths from diseases of the nervous system has been noted among other occupational cohorts exposed to pesticides.