Pharmacokinetic assessment of constituents of Boswellia serrata, pine bark extracts, curcumin in combination including methylsulfonylmethane in healthy volunteers.

OBJECTIVES: Dietary supplements are increasingly used by people with osteoarthritis. Boswellia serrata extract, curcumin, pine bark extract and methylsulfonylmethane have been identified as having the largest effects for symptomatic relief in a systematic review. It is important to understand whether any pharmacokinetic interactions are among the major constituents of these supplements so as to provide information when considering the combination use of these supplements. The aim of this study was to investigate the pharmacokinetics of the constituents alone and in combination. METHODS: This study was a randomized, open-label, single-dose, four-treatment, four-period, crossover study with 1-week washout. The pharmacokinetics of the constituents of these supplements when dosed in combination with methylsulfonylmethane were compared to being administered alone. Plasma samples were obtained over 24 h from 16 healthy participants. Eight major constituents were analysed using a validated ultra-high-performance liquid chromatography-tandem mass spectrometry assay. KEY FINDINGS: The pharmacokinetics of each constituent was characterized, and there were no significant differences in the pharmacokinetic profiles of the constituents when administered as a combination, relative to the constituents when administered alone (P > 0.05). CONCLUSIONS: These data suggest that interactions between the major constituents of this supplement combination are unlikely and therefore could be investigated to manage patients with osteoarthritis without significant concerns for possible pharmacokinetic interactions.

Phase I study of KRP-116D, a 50% w/w dimethyl sulfoxide aqueous solution, on the systemic absorption from bladder by intravesical instillation in healthy Japanese subjects.

OBJECTIVE: This was a single-institution, single-dose, single-arm phase 1 study in healthy adult males to evaluate the safety and absorption of dimethyl sulfoxide (DMSO) from the bladder into the body when KRP-116D (a 50% w/w DMSO solution) was intravesically administered and allowed to remain in the bladder for 15 minutes. METHODS: Six healthy adult males were enrolled in this study. KRP-116D (50 mL) was instilled directly into the bladder via a catheter where it was allowed to remain for 15 minutes under lidocaine anesthesia in accordance with the usage of RIMSO-50 (50% w/w DMSO solution) approved in the USA. The residual DMSO solution in the bladder was collected 15 minutes after instillation. The concentrations of DMSO in the plasma and the recovered solution were analyzed by a validated high-performance liquid chromatography (HPLC) method. The concentration in the residual DMSO solution was multiplied by the solution volume and divided by the dosage to calculate the recovery rate of DMSO. RESULTS: Plasma DMSO was detected in one of six subjects, and in the remaining five subjects DMSO was not detected (<19.6 µg/mL). The recovery rate of DMSO from the bladder was 60.7% to 93.7%. The only drug-related adverse event was breath odor (garlic-like breath) observed in four of six subjects (66.7%). CONCLUSION: Absorption of DMSO from the bladder was low (16.3%), and the systemic exposure was limited. Most of the DMSO was recovered from the bladder. KRP-116D 50 mL was well tolerated and safe.

Penetration monitoring of drugs and additives by ATR-FTIR spectroscopy/tape stripping and confocal Raman spectroscopy - A comparative study.

Vibrational spectroscopy is a useful tool for analysis of skin properties and to confirm the penetration of drugs and other formulation compounds into the skin. In particular, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and confocal Raman spectroscopy (CRS) have been optimised for skin analysis. Despite an impressive amount of data on these techniques, a comparative methodological assessment for skin penetration monitoring of model substances is still amiss. Thus, in vitro skin penetration studies were conducted in parallel using the same porcine material and four model substances, namely sodium laureth sulfate (SLES), sodium dodecyl sulfate (SDS), sulfathiazole sodium (STZ) and dimethyl sulfoxide (DMSO). ATR-FTIR spectroscopy in combination with tape stripping and CRS were employed to evaluate the skin penetration of the applied substances. In addition, the skin hydration status or change in skin hydration after application was investigated. The results show that both methods provide valuable information on the skin penetration potential of applied substances. The penetration profiles determined by CRS or ATR-FTIR/tape stripping were comparable for all substances; a slow decrease in relative substance concentration was visible from the skin surface inwards within the stratum corneum (SC). In general, deeper penetration into the SC was observed with CRS, which may be related to the depth resolution of the employed device. However, when related to the respective total SC thickness of each experiment, the penetration depths determined by parallel CRS and ATR-FTIR analysis were in good agreement for all model substances. The observed order of the penetration depth was DMSO > SDS > SLES > STZ with both techniques. A decrease of the relative concentration to 10% of the maximum value was found approximately between 34 and 89% of total SC thickness. Summarising these findings, advantages and drawbacks of the two techniques for in vitro skin penetration studies are discussed.

Evaluation of novel formulations of d-ß-hydroxybutyrate and melatonin in a rat model of hemorrhagic shock.

d-ß-hydroxybutyrate and melatonin (BHB/MLT) infusion improves survival in hemorrhagic shock models. The original BHB/MLT formulation contains dimethyl sulfoxide (DMSO) to increase melatonin solubility. We formulated BHB/MLT solutions wherein DMSO was replaced either with 10% polyvinylpyrrolidone (BHB/MLT/PVP) or with 5% hydroxypropyl-ß-cyclodextrin/2.5% PVP/2.5% polyethylene glycol 400 (BHB/MLT/CD). Safety and efficacy of the new and the original BHB/MLT solution were tested in a lethal rat hemorrhagic shock model, with seven groups: 1) sham, 2) shock, untreated, 3) shock, lactated Ringer's solution (LR), 4) shock, 4 M BHB/MLT/DMSO, 5) shock, 2 M BHB/MLT/DMSO, 6) shock, BHB/MLT/PVP and 7) shock, BHB/MLT/CD. BHB/MLT/DMSO was given at full strength and 1:1 dilution to match the concentration of the novel formulations. Rats were anesthetized, instrumented, and 40% of the total blood volume was withdrawn in three steps, followed by four-hour long shock. Treatment boluses were infused half-way throughout hemorrhage. Survival was highest in BHB/MLT/CD-treated rats (8/10), followed by the BHB/MLT/PVP (6/10), 4 M BHB/MLT/DMSO (5/10) or 2 M BHB/MLT/DMSO (5/10), LR (3/10) and the untreated group (0/11). Survival did not differ significantly between BHB/MLT groups (p > 0.05), but was significantly higher in BHB/MLT/CD than in LR-treated animals (p = 0.018). BHB/MLT/PVP and BHB/MLT/CD constitute promising candidates for clinical hemorrhagic shock treatment.

Pharmacokinetics, disposition, and plasma concentrations of dimethyl sulfoxide (DMSO) in the horse following topical, oral, and intravenous administration.

Compartmental models were used to investigate the pharmacokinetics of intravenous (i.v.), oral (p.o.), and topical (TOP) administration of dimethyl sulfoxide (DMSO). The plasma concentration-time curve following a 15-min i.v. infusion of DMSO was described by a two-compartment model. Median and range of alpha (t1/2α ) and beta (t1/2ß ) half-lives were 0.029 (0.026-0.093) and 14.1 (6.6-16.4) hr, respectively. Plasma concentration-time curves of DMSO following p.o. and TOP administration were best described by one-compartment absorption and elimination models. Following the p.o. administration, median absorption (t1/2ab ) and elimination (t1/2e ) half-lives were 0.15 (0.01-0.77) and 15.5 (8.5-25.2) hr, respectively. The plasma concentrations of DMSO were 47.4-129.9 µg/ml, occurring between 15 min and 4 hr. The fractional absorption (F) during a 24-hr period was 47.4 (22.7-98.1)%. Following TOP administrations, the median t1/2ab and t1/2e were 1.2 (0.49-2.3) and 4.5 (2.1-11.0) hr, respectively. Plasma concentrations were 1.2-8.2 µg/ml occurring at 2-4 hr. Fractional absorption following TOP administration was 0.48 (0.315-4.4)% of the dose administered. Clearance (Cl) of DMSO following the i.v. administration was 3.2 (2.2-6.7) ml hr-1  kg-1 . The corrected clearances (ClF ) for p.o. and TOP administrations were 2.9 (1.1-5.5) and 4.5 (0.52-18.2) ml hr-1  kg-1 .

Dual-lumen balloon to increase onyx venous penetration in the treatment of spinal dural arteriovenous fistulas.

PURPOSE: Spinal dural arteriovenous fistulas (sDAVF) are the most common spinal vascular lesions. The arterialization of the recipient vein results in venous hypertension and chronic ischemia. Intravascular injection of acrylic glue in order to occlude the draining vein is the principle of endovascular treatment, but a significant portion of embolization procedures do not succeed. We present our initial experience of endovascular balloon augmented embolization of sDAVF using a dual-lumen balloon. CLINICAL PRESENTATION: Three patients harboring sDAVF were submitted to endovascular treatment by onyx injection assisted by a double-lumen balloon as the sole therapy. Control angiography demonstrated complete obliteration of the fistula in all cases with clinical improvement. CONCLUSION: Dual-lumen balloon onyx embolization of spinal dural arteriovenous fistulas appears to be an acceptable and feasible alternative.

[The influence of the main components of the ultraphonophoresis phytocomplex method on the release of the biologically active substances (an experimental study)]. / Vliianie osnovnykh komponentov metoda ul'trafonoforeza fitokompleksa na vysvobozhdenie biologicheski aktivnykh veshchestv (éksperimental'noe issledovanie).

The present study was designed to investigate kinetics of flavonoidrelease from the working compositions containing a phytocomplex. The basic parameters of this processes during phonophoresis were determined in the model in vitro experiments. The study has demonstrated the dependence of the flavonoid release rate on their initial concentration in the working compositions and the influence of dimethylsulfoxide (as well as the main and auxiliary agents of the working composition) on the release of biologically active substances. The technological methods designed for the enhancement of the effectiveness of the phytocomplex phonophoresis technique are proposed.

Methylsulfonylmethane: Applications and Safety of a Novel Dietary Supplement.

Methylsulfonylmethane (MSM) has become a popular dietary supplement used for a variety of purposes, including its most common use as an anti-inflammatory agent. It has been well-investigated in animal models, as well as in human clinical trials and experiments. A variety of health-specific outcome measures are improved with MSM supplementation, including inflammation, joint/muscle pain, oxidative stress, and antioxidant capacity. Initial evidence is available regarding the dose of MSM needed to provide benefit, although additional work is underway to determine the precise dose and time course of treatment needed to provide optimal benefits. As a Generally Recognized As Safe (GRAS) approved substance, MSM is well-tolerated by most individuals at dosages of up to four grams daily, with few known and mild side effects. This review provides an overview of MSM, with details regarding its common uses and applications as a dietary supplement, as well as its safety for consumption.

EVALUATION OF DMSO TRANSPORT IN HUMAN ARTICULAR CARTILAGE: VEHICLE SOLUTIONS AND EFFECTS ON CELL FUNCTION.

Osteochondral allografting techniques are limited by the availability of suitable donor tissue; there is an urgent need for effective cryopreservation. A fundamental requirement is the need to establish initial conditions of exposure to cryoprotectant that the chondrocytes will tolerate and that load the tissue with an adequate concentration of cryoprotectant. Three vehicle solutions to transport DMSO into the tissue were studied. Knee joints were obtained from deceased donors with appropriate consent. Whole condyles were treated with 20% w/w DMSO in each of three vehicle solutions and chondrocyte function and tissue CPA content measured. The results showed that exposure to 20% DMSO in each vehicle solution for 2 hours at 0 degrees C was tolerated without loss of GAG synthetic activity. It was observed that penetration of DMSO increased little after 1 hour of CPA exposure at 0 degrees C but the final tissue concentration of CPA was markedly lower than that in the medium.

Effects of the ruthenium-based drug NAMI-A on the roles played by TGF-ß1 in the metastatic process.

The ruthenium-based drug NAMI-A, characterised by its selectivity against solid tumour metastases, promotes TGF-ß1-dependent fibrosis and the reduction of the release of MMPs in the primary tumour. The aim of the study was to examine the interaction of NAMI-A with TGF-ß1 in the process of metastasis formation. NAMI-A (1) affects the secretion of TGF-ß1 in metastatic MDA-MB-231 cells rather than in non-tumorigenic HBL-100 cells, (2) prevails over TGF-ß1 with regard to the invasive capacity of the treated cells, and (3) contrasts integrin-dependent migration stimulated by TGF-ß1. It, thus, appears that the effects of NAMI-A on cell invasion and migration are best summarised as an interference with TGF-ß1 and a reduction of its activity in these events. At a molecular level, the similar activity of NAMI-A and TGF-ß1 on RhoA GTPase supports its interaction with cell surface integrins while TGF-ß1 can activate it by interaction with its TGFßR receptor. The inhibition of TGF-ß1-induced migration of MDA-MB-231 cells by NAMI-A cannot simply be attributed to a modulation of the Smad2 and p38MAPK pathways. In conclusion, the effects of NAMI-A on the biological role of TGF-ß1 in cancer metastasis are insufficient to attribute the responsibility for the anti-metastatic activity of the ruthenium-based drug to this target alone.

Phase I/II study with ruthenium compound NAMI-A and gemcitabine in patients with non-small cell lung cancer after first line therapy.

BACKGROUND: This phase I/II study determined the maximal tolerable dose, dose limiting toxicities, antitumor activity, the pharmacokinetics and pharmacodynamics of ruthenium compound NAMI-A in combination with gemcitabine in Non-Small Cell Lung Cancer patients after first line treatment. METHODS: Initial dose escalation of NAMI-A was performed in a 28 day cycle: NAMI-A as a 3 h infusion through a port-a-cath at a starting dose of 300 mg/m(2) at day 1, 8 and 15, in combination with gemcitabine 1,000 mg/m(2) at days 2, 9 and 16. Subsequently, dose escalation of NAMI-A in a 21 day schedule was explored. At the maximal tolerable dose level of this schedule an expansion group was enrolled of which 15 patients were evaluable for response. RESULTS: Due to frequent neutropenic dose interruptions in the third week, the 28 day schedule was amended into a 21 day schedule. The maximal tolerable dose was 300 and 450 mg/m(2) of NAMI-A (21 day schedule). Main adverse events consisted of neutropenia, anemia, elevated liver enzymes, transient creatinine elevation, nausea, vomiting, constipation, diarrhea, fatigue, and renal toxicity. CONCLUSION: NAMI-A administered in combination with gemcitabine is only moderately tolerated and less active in NSCLC patients after first line treatment than gemcitabine alone.

Influence of the binding of reduced NAMI-A to human serum albumin on the pharmacokinetics and biological activity.

NAMI-A is a ruthenium-based drug endowed with the unique property of selectively targeting solid tumour metastases. Although two clinical studies had already been completed, limited information exists on the behavior of NAMI-A after injection into the bloodstream. PK data in humans informs us of a rather low free drug concentration, of a relatively high half-life time of elimination and of a linear relationship between the administered dose and the corresponding AUC for up to toxic doses. In the present study, we examined the chemical kinetics of albumin binding with or without the presence of reducing agents, and we evaluated how these chemical aspects might influence the in vivo PK and the in vitro ability of NAMI-A to inhibit cell migration, which is a bona fide, rapid and easy way to suggest anti-metastatic properties. The experimental data support the binding of NAMI-A to serum albumin. The reaction is facilitated when the drug is in its reduced form and, in agreement with already reported data, the adduct formed with albumin maintains the biological activity of the ruthenium drug. The formation of the adduct is favored by low ratios of NAMI-A : HSA and by the reduction of the drug with ascorbic acid. The difference in in vivo PK and the faster binding to albumin of the reduced NAMI-A seem to suggest that the drug is not rapidly reduced immediately upon injection, even at low doses. Most probably, cell and protein binding prevail over the reduction of the drug. This observation supports the thesis that the reduction of the drug before injection must be considered relevant for the pharmacological activity of NAMI-A against tumour metastases.

Preclinical combination therapy of the investigational drug NAMI-A(+) with doxorubicin for mammary cancer.

AIM OF THE STUDY: The tumor metastases targeting ruthenium complex NAMI-A synergistically improves the activity of gemcitabine in combination therapies. High-throughput screening was used to identify other potential drug combinations from a library of FDA approved drugs. Doxorubicin was identified as a hit compound and was therefore evaluated in combination with NAMI-A in vitro and in a preclinical in vivo model. RESULTS: High-throughput screening identified eight structurally diverse compounds that synergize with NAMI-A including doxorubicin. The combination index on MCF-7 cells showed synergism as the concentration of NAMI-A increases independent of the doxorubicin concentration. In MCa mammary carcinoma of CBA mice, NAMI-A (35 mg/kg/day i.p. on days 7-12) followed by doxorubicin (10 mg/kg i.p. on day 16), significantly increased the effects of the individual drugs on metastases with 70 % animals resulting free of macroscopically detectable tumor nodules in the lungs at sacrifice. NAMI-A, unlike doxorubicin, cured 60 % of the treated mice but the combination therapy was toxic to the animals. CONCLUSIONS: The combined therapy of NAMI-A with doxorubicin synergizes on lung metastasis in a preclinical mouse model. The combination therapy at the maximum tolerated doses of the two drugs is toxic. Hence, this combination is not suitable for clinical studies using maximum tolerated doses.

Infrared spectroscopic imaging tracks lateral distribution in human stratum corneum.

PURPOSE: To demonstrate the efficacy of infrared (IR) spectroscopic imaging for evaluation of lateral diffusion in stratum corneum (SC) and for elucidation of intermolecular interactions between exogenous agents and SC constituents. METHODS: In separate experiments, acyl chain perdeuterated oleic acid (OA-d) and deuterated dimethyl sulfoxide (DMSO-d) were applied to the surface of isolated human SC. The lateral distribution of permeant concentrations was monitored using the time-dependence of IR images. Diffusion coefficients (D) were estimated from Fick's second law. Interactions between the exogenous agents and the SC were tracked from changes in CD2 and Amide I stretching frequencies. RESULTS: Networked glyphs served as the major pathway for lateral distribution of OA-d. In glyph-poor regions, D values from 0.3-1 × 10(-8) cm(2)/s bracketed the OA-d data and apparently decreased with time. Although diffusion of DMSO-d is relatively fast compared to our experimental measurement time, the results suggest values of ~10(-7) cm(2)/s. OA-d spectral changes suggest penetration into the ordered lipids of the SC; DMSO-d penetration results in perturbation of SC keratin structure. CONCLUSIONS: IR imaging provides concentration profiles, diffusion coefficients, and unique molecular level information about structural changes in the endogenous SC constituents and exogenous agents upon their mutual interaction. Transport along glyphs is the dominant mode of distribution for OA-d.

Dimethyl sulfoxide could be a useful probe to evaluate unusual skin angioneurotic reaction and epidermal permeability.

BACKGROUND/OBJECTIVES: Dimethyl sulfoxide (DMSO) has been suggested as a traditional chemical probe for assessing skin susceptibility and barrier function. The purpose of this study was to determine the role of DMSO test for the evaluation of unusual skin angioneurotic reaction and epidermal permeability. METHODS: Thirty healthy volunteers were exposed to 98% DMSO on the flexor forearm skin for three exposure durations (5 min, 10 min and 15 min). Clinical visual score and biological physical parameters were obtained. The volunteers were divided into two groups according to the clinical visual scoring. The skin parameters were subsequently analyzed. RESULTS: There was a significant correlation between clinical visual score and biological physical parameters. The skin color parameters (a*, oxyhemoglobin, erythema and melanin index) and blood flow values were significant between two groups regardless of duration of DMSO exposure, and a significant difference between density values could also be detected if we regrouped the volunteers according to the sting-producing score. Our results also suggested there was no correlation between questionnaire score and clinical visual score or other parameters. CONCLUSIONS: Application of 98% DMSO for 10 min combined with a* (at 30 min) and blood flow (at 10 min) values could help us to identify persons with a hyper-angionerotic reaction to chemical stimulus. The penetrative activity of DMSO correlated with the thickness of the individual's skin.

[Permeability of isolated rat hepatocyte plasma membranes for molecules of dimethyl sulfoxide].

We have studied permeability of isolated rat hepatocyte membranes for molecules of dimethyl sulfoxide (DMSO) at different hypertonicity of a cryoprotective medium. The permeability coefficient of hepatocyte membranes κ1 for DMSO molecules was shown to be the differential function of osmotic pressure between a cell and an extracellular medium. Ten-fold augmentation of DMSO concentration in the cryoprotective medium causes the decrease of permeability coefficients κ1 probably associated with the increased viscosity in membrane-adjacent liquid layers as well as partial limitations appeared as a result of change in cell membrane shape after hepatocyte dehydration. We have found out that in aqueous solutions of NaCl (2246 mOsm/l) and DMSO (2250 mOsm/l) the filtration coefficient L(p) in the presence of a penetrating cryoprotectant (L(pDMSO) = (4.45 ± 0.04) x 10(-14) m3/Ns) is 3 orders lower compared to the case with electrolyte (L(pNaCl) = (2.25 ± 0.25) x 10(-11) m3/Ns). This phenomenon is stipulated by the cross impact of flows of a cryoprotectant and water at the stage of cell dehydration. Pronounced lipophilicity of DMSO, geometric parameters of its molecule as well as the presence of large aqueous pores in rat hepatocyte membranes allow of suggesting the availability of two ways of penetrating this cryoprotectant into the cells by non-specific diffusion through membrane lipid areas and hydrophilic channels.

Rapid movement of water and cryoprotectants in pig expanded blastocysts via channel processes: its relevance to their higher tolerance to cryopreservation.

Pig oocytes and embryos are highly sensitive to cryopreservation; however, tolerance to cryopreservation increases in embryos at the expanded blastocyst stage. This increased tolerance may be attributed to a decrease in cytoplasmic lipid droplets at this stage. We previously showed that an increase in the permeability of the plasma membrane in mouse oocytes to water and cryoprotectants, caused by the artificial expression of aquaporin 3, an aquaglyceroporin, enhanced tolerance to cryopreservation. In the present study, we investigated whether membrane permeability was also involved in the tolerance of pig embryos to cryopreservation. The permeability of oocytes and morulae to water and glycerol was low, whereas that of expanded blastocysts was high. Activation energy for permeability to water, glycerol, ethylene glycol, and dimethyl sulfoxide was markedly lower for expanded blastocysts than for oocytes. This suggests that water and these cryoprotectants move through expanded blastocysts predominantly by facilitated diffusion and through oocytes predominantly by simple diffusion. Aquaporin 3 mRNA was expressed in expanded blastocysts abundantly, but less so in oocytes. On the other hand, the permeability of expanded blastocysts to propylene glycol was as low as that of oocytes, and activation energy for its permeability was similar to that of oocytes, which suggests that propylene glycol moves through oocytes and embryos predominantly by simple diffusion. These results suggest that the higher tolerance of pig expanded blastocysts to cryopreservation is also related to high membrane permeability due to the expression of water/cryoprotectant channels, in addition to the decrease in cytoplasmic lipid droplets.

Discrimination of dimethyl sulphoxide diffusion coefficient in the process of optical clearing by confocal micro-Raman spectroscopy.

Confocal micro-Raman spectroscopy is employed to study the diffusion process of dimethyl sulfoxide (DMSO) in porcine skin optical clearing. The variation of DMSO concentration with time at different depths of the skin was obtained and then the DMSO diffusion coefficient with the passive diffusion model was calculated. Results show that it has a significant difference at different depths of the skin. Also, the DMSO concentration with the depth at different times was obtained and the same method was used to find the change law of the DMSO diffusion coefficient. Results indicate that it also changes with the treatment time. The experimental results are consistent with the theoretical model in a previous study. The current results demonstrate that Raman spectroscopy has the ability to quantitatively monitor the process of optical clearing.

Dimethyl sulfoxide (DMSO) as a potential contrast agent for brain tumors.

Dimethyl sulfoxide (DMSO) is commonly used in preclinical studies of animal models of high-grade glioma as a solvent for chemotherapeutic agents. A strong DMSO signal was detected by single-voxel MRS in the brain of three C57BL/6 control mice during a pilot study of DMSO tolerance after intragastric administration. This led us to investigate the accumulation and wash-out kinetics of DMSO in both normal brain parenchyma (n=3 control mice) by single-voxel MRS, and in 12 GL261 glioblastomas (GBMs) by single-voxel MRS (n=3) and MRSI (n=9). DMSO accumulated differently in each tissue type, reaching its highest concentration in tumors: 6.18 ± 0.85 µmol/g water, 1.5-fold higher than in control mouse brain (p<0.05). A faster wash-out was detected in normal brain parenchyma with respect to GBM tissue: half-lives of 2.06 ± 0.58 and 4.57 ± 1.15 h, respectively. MRSI maps of time-course DMSO changes revealed clear hotspots of differential spatial accumulation in GL261 tumors. Additional MRSI studies with four mice bearing oligodendrogliomas (ODs) revealed similar results as in GBM tumors. The lack of T(1) contrast enhancement post-gadolinium (gadopentetate dimeglumine, Gd-DTPA) in control mouse brain and mice with ODs suggested that DMSO was fully able to cross the intact blood-brain barrier in both normal brain parenchyma and in low-grade tumors. Our results indicate a potential role for DMSO as a contrast agent for brain tumor detection, even in those tumors 'invisible' to standard gadolinium-enhanced MRI, and possibly for monitoring heterogeneities associated with progression or with therapeutic response.