Heavy ion beam measurement of the hydration of cementitious materials.

The setting and development of strength of Portland cement concrete depends upon the reaction of water with various phases in the Portland cement. Nuclear resonance reaction analysis (NRRA) involving the (1)H((15)N,alpha,gamma)(12)C reaction has been applied to measure the hydrogen depth profile in the few 100 nm thick surface layer that controls the early stage of the reaction. Specific topics that have been investigated include the reactivity of individual cementitious phases and the effects of accelerators and retarders.

12C+12C fusion reactions near the Gamow energy.

The fusion reactions 12C(12C,alpha)20Ne and 12C(12C,p)23Na have been studied from E=2.10 to 4.75 MeV by gamma-ray spectroscopy using a C target with ultralow hydrogen contamination. The deduced astrophysical S(E)* factor exhibits new resonances at E< or =3.0 MeV, in particular, a strong resonance at E=2.14 MeV, which lies at the high-energy tail of the Gamow peak. The resonance increases the present nonresonant reaction rate of the alpha channel by a factor of 5 near T=8x10(8) K. Because of the resonance structure, extrapolation to the Gamow energy EG=1.5 MeV is quite uncertain. An experimental approach based on an underground accelerator placed in a salt mine in combination with a high efficiency detection setup could provide data over the full EG energy range.

Aberrant redox regulation in human metastatic melanoma cells compared to normal melanocytes.

Melanocytes and melanoma cells contain melanin, a complex polymer that modulates redox changes in these cells. Relative intracellular hydrogen peroxide levels measured by dichlorodihydrofluorescein are similar in the two cell types, but the levels of superoxide anion measured by dihydroethidium were markedly increased in melanoma cells. Chelator-induced oxidative stress is efficiently suppressed by melanocytes without substantial recruitment of the transcription factors NF-kappaB and AP-1 as measured by electrophoretic mobility shift assay and quantitated by densitometry or by a change in frequency of apoptosis as determined by annexin V binding. In contrast, NF-kappaB in melanoma cells is strongly recruited by changes in redox status and exhibits a correlative relationship to intracellular hydrogen peroxide (but not superoxide anion). However, the response of the NF-kappaB pathway to intracellular hydrogen peroxide is anomalous, including downregulation of p65 and IkappaBalpha RNA expression (Northern blot). Additionally, recruitment of AP-1 binding in melanoma cells was directly correlated with intracellular levels of superoxide anion (but not hydrogen peroxide). Neither the degree of NF-kappaB nor AP-1 binding in melanoma cells was related to the frequency of apoptosis. The responsiveness of NF-kappaB and AP-1 recruitment to intracellular levels of hydrogen peroxide and superoxide anion without concomitant control of apoptosis provides a general mechanism by which these cells can escape noxious injury (e.g., chemotherapy). The marked enhancement of apoptosis in melanoma cells by chelators indicates, however, that this alteration can be circumvented and offers a unique therapeutic window to explore.

Testicular choriocarcinoma metastatic to the skin: an additional case and literature review.

Choriocarcinoma, a malignancy of trophoblastic cells, is characterized by the secretion of human chorionic gonadotropin (hCG). Choriocarcinoma primarily arises from the fetal (placental) trophoblasts in the setting of a molar pregnancy. Nongestational choriocarcinoma from the ovary or testis is much rarer. Testicular choriocarcinoma is a malignant tumor with great propensity for distant metastasis. The primary sites of metastasis are the lungs, liver, and brain. Skin metastasis is very rare but portends a grave prognosis when diagnosed. We present the case of a 24-year-old white male with a testicular mixed germ-cell tumor with skin metastases of choriocarcinoma.

Valproic acid treatment of chronic daily headache.

The efficacy of valproic acid in the treatment of intractable chronic daily headache, unresponsive to traditional prophylactic medications, was examined prospectively in 16 patients. Dosage of the medication was adjusted to maintain serum valproic acid levels between 50 and 100 micrograms/mL, provided there were no significant side effects at that level. Valproic acid prophylaxis was of some benefit in only 2 of 16 patients. One of these two patients discontinued therapy due to side effects. Eight of the 16 patients reported side effects which included nausea, diarrhea, anorexia, lethargy, sleepiness, confusion, blurred vision, and decreased libido. In conclusion, valproic acid was not effective in controlling chronic daily headache in the majority of patients in whom conventional therapy had failed, and 50% of patients reported side effects. There is a significant disparity in the reported efficacy of this drug in treating chronic daily headache. This disparity is most likely due to the poorly-defined nature of this variety of headache. It is, therefore, recommended that more stringent definition of this disorder be developed before therapeutic regimens are evaluated.