Tumour pH and response to chemotherapy: an in vivo 31P magnetic resonance spectroscopy study in non-Hodgkin's lymphoma

The alkaline diet: is there evidence that an alkaline pH diet benefits health?

This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

Early detection of radiation therapy response in non-Hodgkin's lymphoma xenografts by in vivo 1H magnetic resonance spectroscopy and imaging

The purpose of the study was to investigate the capability of (1)H MRS and MRI methods for detecting early response to radiation therapy in non-Hodgkin's lymphoma (NHL). Studies were performed on the WSU-DLCL2 xenograft model in nude mice of human diffuse large B-cell lymphoma, the most common form of NHL. Radiation treatment was applied as a single 15 Gy dose to the tumor. Tumor lactate, lipids, total choline, T(2) and apparent diffusion coefficients (ADC) were measured before treatment and at 24 h and 72 h after radiation. A Hadamard-encoded slice-selective multiple quantum coherence spectroscopy sequence was used for detecting lactate (Lac) while a stimulated echo acquisition mode sequence was used for detection of total choline (tCho) and lipids. T(2)- and diffusion-weighted imaging sequences were used for measuring T(2) and ADC. Within 24 h after radiation, significant changes were observed in the normalized integrated resonance intensities of Lac and the methylenes of lipids. Lac/H(2)O decreased by 38 +/- 15% (p = 0.03), and lipid (1.3 ppm, CH(2))/H(2)O increased by 57 +/- 14% (p = 0.01). At 72 h after radiation, tCho/H(2)O decreased by 45 +/- 14% (p = 0.01), and lipid (2.8 ppm, polyunsaturated fatty acid)/H(2)O increased by 970 +/- 36% (p = 0.001). ADC increased by 14 +/- 2% (p = 0.003), and T(2) did not change significantly. Tumor growth delay and regression were observed thereafter. This study enabled comparison of the relative sensitivities of various (1)H MRS and MRI indices to radiation and suggests that (1)H MRS/MRI measurements detect early responses to radiation that precede tumor volume changes.

In vivo MRS markers of response to CHOP chemotherapy in the WSU-DLCL2 human diffuse large B-cell lymphoma xenograft

To identify 1H-MRS molecular biomarkers of early clinical therapeutic response in non-Hodgkin's lymphoma, an in vivo longitudinal study was performed on human non-Hodgkin's diffuse large B-cell lymphoma xenografts (WSU-DLCL2) grown in the flanks of female SCID mice. 31P-MRS measurements, which have been demonstrated to be prognostic clinical indices of response (Arias-Mendoza et al. Acad. Radiol. 2004; 11: 368-376) but which provide lower spatial resolution, were included for comparison. The animals received CHOP (cyclophosphamide, hydroxydoxorubicin, oncovin and prednisone) chemotherapy for three 1-week cycles, resulting in stable disease based on tumor volume. Localization of total choline and phosphorus metabolites in vivo was achieved with stimulated echo acquisition mode and image selected in vivo spectroscopy sequences, respectively. Significant decreases in lactate were detected by the selective multiple quantum coherence spectral editing technique after the first cycle of CHOP, whereas total choline and the phosphomonoester/nucleoside triphosphate ratio did not change until the third cycle. Ex vivo extract MRS of tumors corroborated the in vivo results. Histological staining with antibodies to Ki67 revealed a decrease in proliferation rate in CHOP-treated tumors that coincided with the decrease in lactate. This study demonstrates the utility of lactate as an early proliferation-sensitive indicator of therapeutic response in a mouse model of non-Hodgkin's lymphoma and serves as a basis for future clinical implementation of these methods.

MR imaging of therapy-induced changes of bone marrow

MR imaging of bone marrow infiltration by hematologic malignancies provides non-invasive assays of bone marrow cellularity and vascularity to supplement the information provided by bone marrow biopsies. This article will review the MR imaging findings of bone marrow infiltration by hematologic malignancies with special focus on treatment effects. MR imaging findings of the bone marrow after radiation therapy and chemotherapy will be described. In addition, changes in bone marrow microcirculation and metabolism after anti-angiogenesis treatment will be reviewed. Finally, new specific imaging techniques for the depiction of regulatory events that control blood vessel growth and cell proliferation will be discussed. Future developments are directed to yield comprehensive information about bone marrow structure, function and microenvironment.

Tumour phospholipid metabolism

Following the impetus of early clinical and experimental investigations, in vivo and in vitro MRS studies of tumours pointed in the eighties to the possible significance of signals arising from phospholipid (PL) precursors and catabolites as novel biochemical indicators of in vivo tumour progression and response to therapy. In the present decade, MRS analyses of individual components contributing to the 31P PME (phosphomonoester) and PDE (phosphodiester) resonances, as well as to the 1H 'choline peak', have reinforced some of these expectations. Moreover, the absolute quantification of these signals provided the basis for addressing more specific (although still open) questions on the biochemical mechanisms responsible for the formation of intracellular pools of PL derivatives in tumours, under different conditions of cell proliferative status and/or malignancy level. This article is aimed at providing an overview on: (a) quantitative MRS measurements on the contents of phosphocholine (PCho), phosphoethanolamine (PEtn) and their glycerol derivatives ģlycerol 3-phosphocholine (GPC) and glycerol 3-phosphoethanolamine (GPE)[ in human tumours and cells (with particular attention to breast and brain cancer and lymphomas), as well as in normal mammalian tissues (including developing organs and rapidly proliferating tissues); (b) possible correlations of MRS parameters like PEtn/PCho and PCho/GPC ratios with in vitro cell growth status and/or cell tumorigenicity; and (c) current and new hypotheses on the role and interplay of biosynthetic and catabolic pathways of the choline and ethanolamine cycles in modulating the intracellular sizes of PCho and PEtn pools, either in response to mitogenic stimuli or in relation to malignant transformation.

Nitrogen mustard up-regulates Bcl-2 and GSH and increases NTP and PCr in HT-29 colon cancer cells

We hypothesized that unexplained increases in nucleoside triphosphates (NTP) observed by 31P magnetic resonance spectroscopy (MRS) after treatment of tumours by DNA-damaging agents were related to chemotherapy-induced up-regulation of the bcl-2 gene and DNA damage prevention and repair processes. To test this hypothesis, we treated HT-29 cells with 10(-4) M nitrogen mustard (HN2) and performed sequential perchloric acid extractions in replicate over 0-18 h. By reference to an internal standard (methylene diphosphonic acid), absolute changes in 31P-detectable high-energy phosphates in these extracts were determined and correlated with changes in bcl-2 protein levels, cell viability, cell cycle, apoptosis and total cellular glutathione (GSH) (an important defence against DNA damage from alkylating agents). After HN2 administration, bcl-2 protein levels in the HT-29 cell line rose at 2 h. Cell viability declined to 25% within 18 h, but apoptosis measured using fluorescence techniques remained in the 1-4% range. Increased cell division was noted at 4 h. Two high-energy interconvertible phosphates, NTP (P < or = 0.006) and phosphocreatine (PCr) (P < or = 0.0002), increased at 2 h concurrently with increased levels of bcl-2 protein and glutathione. This study demonstrates that bcl-2 and glutathione are up-regulated by HN2 and links this to a previously unexplained 31P MRS phenomenon: increased NTP after chemotherapy.

Characterization of a murine lymphoma cell line by 31P-NMR spectroscopy: in vivo monitoring of the local anti-tumor effects of systemic immune cell transfer

The intradermal ESb-MP murine T-cell lymphoma in syngeneic DBA/2 mice has been used as a model for adoptive immunotherapy (ADI). Cultured ESb-MP cells were characterized in suspension by 31P-NMR spectroscopy (MRS) at 11.7 T, and solid primary tumors were examined by 31P-MRS in vivo at 7.0 Tesla using surface-coil techniques. Growing tumors contained relatively high levels of phosphomonoesters (PME, predominantly phosphoethanolamine), nucleotides (NTP) and Pi, low levels of phosphodiesters (PDE) and no phosphocreatine. Mean tissue pH was found to be 6.7-6.9. The spectra of ESb-MP cells cultured in RPMI medium (containing choline but no ethanolamine) also showed low PDE and no phosphocreatine at an intracellular pH of 7.4; however, only a trace amount of phosphoethanolamine was detected and significant levels of nucleoside mono- and diphosphates were observed. The complete ADI treatment protocol involved low-dose irradiation (5 Gy) followed by i.v. transfer of immune spleen cells from allogeneic B10.D2 donors and resulted in 100% remission (responders); no treatment or incomplete ADI (irradiation or immune cell transfer alone) resulted in no remissions (nonresponders). In vivo MRS could best discriminate between responders and non-responders on the basis of tissue pH, which increased in responders to 7.0 by day 5-6 after complete ADI. Following therapy, the sum of PME + Pi (both absolute and as a percent of total phosphates) decreased significantly only for responders but only after a visible decrease in tumor volume was apparent.

Accumulation of technetium-99m methylene diphosphonate. Conditions affecting adsorption to hydroxyapatite

Experiments were carried out to explore the mechanism of technetium-99m methylene diphosphonate (99mTc-MDP) adsorption with various calcium compounds including hydroxyapatite powder. 99mTc-MDP adsorption to hydroxyapatite was markedly inhibited by the addition of either pyrophosphate or methylene diphosphonate (MDP). Moreover, adsorbed 99mTc-MDP was partly removed by rinsing with pyrophosphate solution. Adsorption was pH-dependent and was inhibited by univalent cations, adenosine triphosphate solution, and guanosine triphosphate. Adsorption was most apparent to hydroxyapatite and calcium pyrophosphate and was less marked for the other calcium compounds tested. It is suggested that 99mTc-MDP adsorption is affected by the hydroxyapatite crystalline structure and environmental factors such as pH and the presence of phosphates, calcium compounds, and various cations.