Chemical Exchange Saturation Transfer (CEST) Signal at -1.6 ppm and Its Application for Imaging a C6 Glioma Model.

The chemical exchange saturation transfer (CEST) signal at -1.6 ppm is attributed to the choline methyl on phosphatidylcholines and results from the relayed nuclear Overhauser effect (rNOE), that is, rNOE(-1.6). The formation of rNOE(-1.6) involving the cholesterol hydroxyl is shown in liposome models. We aimed to confirm the correlation between cholesterol content and rNOE(-1.6) in cell cultures, tissues, and animals. C57BL/6 mice (N = 9) bearing the C6 glioma tumor were imaged in a 7 T MRI scanner, and their rNOE(-1.6) images were cross-validated through cholesterol staining with filipin. Cholesterol quantification was obtained using an 18.8-T NMR spectrometer from the lipid extracts of the brain tissues from another group of mice (N = 3). The cholesterol content in the cultured cells was manipulated using methyl-ß-cyclodextrin and a complex of cholesterol and methyl-ß-cyclodextrin. The rNOE(-1.6) of the cell homogenates and their cholesterol levels were measured using a 9.4-T NMR spectrometer. The rNOE(-1.6) signal is hypointense in the C6 tumors of mice, which matches the filipin staining results, suggesting that their tumor region is cholesterol deficient. The tissue extracts also indicate less cholesterol and phosphatidylcholine contents in tumors than in normal brain tissues. The amplitude of rNOE(-1.6) is positively correlated with the cholesterol concentration in the cholesterol-manipulated cell cultures. Our results indicate that the cholesterol dependence of rNOE(-1.6) occurs in cell cultures and solid tumors of C6 glioma. Furthermore, when the concentration of phosphatidylcholine is carefully considered, rNOE(-1.6) can be developed as a cholesterol-weighted imaging technique.

Improvement of late life depression after therapeutic enoxaparin: two case reports.

OBJECTIVE: Late life depression (LLD) may have a significant vascular component. While this organic basis remains controversial it would explain the refractory nature of LLD. Moreover, depression is a risk factor for venous thrombus embolism (VTE). This paper aims to describe two elderly patients with LLD who developed and were treated for pulmonary embolism (PE). METHODS: Two cases of elderly patients who developed PE while they were undergoing inpatient treatment for depression are presented. This is discussed using the vascular and the cytokine hypotheses of depression as an explanatory framework. RESULTS: Both patients showed significant clinical improvement in their mental state following therapeutic enoxaparin despite no other changes to their management of depression. This observed benefit of enoxaparin can be explained by the vascular hypothesis of LLD, and possibly the cytokine hypothesis of major depression. CONCLUSION: Enoxaparin may be a novel adjunct to the treatment of depression in elderly patients. The possible benefit of enoxaparin would require further study to exclude a coincidence in these clinical cases.

Cryptococcal phospholipase B antigen is not detected in serum of patients infected with Cryptococcus neoformans using a sandwich enzyme-linked immunosorbent assay.

Extracellular phospholipase B (PLB) is a virulence determinant of Cryptococcus neoformans and Cryptococcus gattii. In this study, we developed a sensitive enzyme-linked immunosorbent assay (ELISA) for PLB antigen with a detection limit of 3.9 ng mL(-1). PLB was detected in culture supernatants of C. neoformans and C. gattii. PLB, however, was not detected in sera of seven human patients and 10 feline patients with active cryptococcosis. Furthermore, none of five rats with extensive pulmonary C. gattii infection had a positive ELISA test result. In conclusion, cryptococcal PLB could not be detected in serum using a PLB antigen-based ELISA. Despite its sensitivity, this ELISA is of limited diagnostic value. Exploration of further extracellular molecules suitable for serodiagnosis of active cryptococcal infection is warranted.

Development of a nested qualitative real-time PCR assay to detect Aspergillus species DNA in clinical specimens.

We adapted a nested Aspergillus PCR to a nested qualitative real-time format on a Light Cycler system. An evaluation using 134 clinical specimens showed that the real-time PCR assay significantly reduced the time for results to be made available without compromising sensitivity and was less labor-intensive. Its use will aid in the rapid diagnosis of invasive aspergillosis.