Renal imaging in patients with renal impairment.

In patients with renal impairment, the incremental benefits from administration of contrast media for imaging studies need to be carefully assessed relative to the potential increased risks of worsening renal dysfunction and systemic adverse effects. This review provides an overview of risk and benefits of iodinated and gadolinium-based contrast agents; examines their relationships to contrast-induced nephropathy (CIN) and nephrogenic systemic fibrosis (NSF), respectively; and discusses various clinical strategies to minimize the risk of CIN and NSF. Specifically, renal imaging strategies aimed to minimize the adverse effects of contrast media as well as alternatives to iodinated and gadolinium-based contrast-enhanced renal imaging are proposed with emphasis on non-contrast-enhanced magnetic resonance imaging.

Pulsed high-intensity focused ultrasound enhances apoptosis and growth inhibition of squamous cell carcinoma xenografts with proteasome inhibitor bortezomib.

PURPOSE: To investigate whether combining pulsed high-intensity focused ultrasound (HIFU) with the chemotherapeutic drug bortezomib could improve antitumor activity against murine squamous cell carcinoma (SCC) tumors. MATERIALS AND METHODS: All experiments were conducted with animal care and use committee approval. Murine SCC cells were implanted subcutaneously in C3H mice. When tumors reached 100 mm(3), mice were randomized to one of three groups for twice weekly intraperitoneal injections of 1.5 mg of bortezomib per kilogram of body weight, a proteasome inhibitor (n = 10); 1.0 mg/kg bortezomib (n = 11); or a control vehicle (n = 12). Within each group, half of the mice received pulsed HIFU exposure to their tumors immediately prior to each injection. The time for tumors to reach 650 mm(3) was compared among groups. Additional tumors were stained with terminal deoxynucledotidyl transferase-mediated dUTP nick end labeling and CD31 to assess apoptotic index and blood vessel density, respectively. RESULTS: Tumors in the control group, pulsed HIFU and control group, and 1.0 mg/kg of bortezomib alone group reached the size end point in 5.2 days +/- 0.8 (standard deviation), 5.3 days +/- 0.8, and 5.6 days +/- 1.1, respectively. However, pulsed HIFU and 1.0 mg/kg bortezomib increased the time to end point to 9.8 days +/- 2.9 (P < .02), not significantly different from the 8.8 days +/- 2.1 in tumors treated with 1.5 mg/kg bortezomib alone (P > .05). Combination therapy was also associated with a significantly higher apoptotic index (P < .05). CONCLUSION: Treatment of tumors with pulsed HIFU lowered the threshold level for efficacy of bortezomib, resulting in significant tumor cytotoxicity and growth inhibition at lower dose levels.

Frequency and histopathologic basis of hepatic surface nodularity in patients with fulminant hepatic failure.

PURPOSE: To determine the frequency and histopathologic basis of hepatic surface nodularity at imaging in patients with fulminant hepatic failure. MATERIALS AND METHODS: The committee on human research approved this HIPAA-compliant study and waived written informed consent. Thirty-five consecutive patients [24 female [mean age, 38 years +/- 19 (standard deviation); range, 1-67 years] and 11 male [mean age, 29 years +/- 22; range, 2-61 years]] with a mean age of 35 years +/- 20 (range, 1-67 years) who underwent liver transplantation for fulminant hepatic failure at our institution during a 5-year period were retrospectively identified. Pretransplant ultrasonographic (n = 38; three patients each had two studies) and computed tomographic (n = 2) studies were retrospectively and independently reviewed for hepatic surface nodularity. Liver explant histopathologic findings (n = 33; slides unavailable in two patients) were reviewed for cirrhosis and for the combination of alternating foci of confluent regenerative nodules and necrosis. Differences among patients with nodular versus smooth liver surfaces in the proportion with the two histopathologic findings were compared with Fisher exact test. Differences in illness duration and maximum liver biochemical indices were compared with Mann-Whitney Rank Sum test. RESULTS: Fifteen of 35 patients (43%) demonstrated hepatic surface nodularity at pretransplant imaging, none of whom had cirrhosis at histopathologic examination. One patient with a smooth liver surface had cirrhosis. Compared with those who had a smooth liver surface, patients with hepatic surface nodularity had a significantly greater proportion with the histopathologic finding of a combination of alternating foci of confluent regenerative nodules and necrosis (12 of 14 vs one of 19, P < .001), longer illness duration (31 days +/- 32 vs 13 days +/- 13, P = .029), and lower maximum liver biochemical indices. CONCLUSION: Hepatic surface nodularity is commonly seen at imaging in fulminant hepatic failure and usually reflects a combination of alternating foci of confluent regenerative nodules and necrosis; this is important because an erroneous radiologic diagnosis of cirrhosis in this setting could adversely affect transplantation status.

Pulsed-high intensity focused ultrasound and low temperature-sensitive liposomes for enhanced targeted drug delivery and antitumor effect.

PURPOSE: To determine if pulsed-high intensity focused ultrasound (HIFU) could effectively serve as a source of hyperthermia with thermosensitive liposomes to enhance delivery and efficacy of doxorubicin in tumors. EXPERIMENTAL DESIGN: Comparisons in vitro and in vivo were carried out between non-thermosensitive liposomes (NTSL) and low temperature-sensitive liposomes (LTSL). Liposomes were incubated in vitro over a range of temperatures and durations, and the amount of doxorubicin released was measured. For in vivo experiments, liposomes and free doxorubicin were injected i.v. in mice followed by pulsed-HIFU exposures in s.c. murine adenocarcinoma tumors at 0 and 24 h after administration. Combinations of the exposures and drug formulations were evaluated for doxorubicin concentration and growth inhibition in the tumors. RESULTS: In vitro incubations simulating the pulsed-HIFU thermal dose (42 degrees C for 2 min) triggered release of 50% of doxorubicin from the LTSLs; however, no detectable release from the NTSLs was observed. Similarly, in vivo experiments showed that pulsed-HIFU exposures combined with the LTSLs resulted in more rapid delivery of doxorubicin as well as significantly higher i.t. concentration when compared with LTSLs alone or NTSLs, with or without exposures. Combining the exposures with the LTSLs also significantly reduced tumor growth compared with all other groups. CONCLUSIONS: Combining low-temperature heat-sensitive liposomes with noninvasive and nondestructive pulsed-HIFU exposures enhanced the delivery of doxorubicin and, consequently, its antitumor effects. This combination therapy could potentially produce viable clinical strategies for improved targeting and delivery of drugs for treatment of cancer and other diseases.

Differences between genders in colorectal morphology on CT colonography using a quantitative approach: a pilot study.

PURPOSE: To explore quantitative differences between genders in morphologic colonic metrics and determine metric reproducibility. METHODS: Quantitative colonic metrics from 20 male and 20 female CTC datasets were evaluated twice by two readers; all exams were performed after incomplete optical colonoscopy. Intra-/inter-reader reliability was measured with intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC). RESULTS: Women had overall decreased colonic volume, increased tortuosity and compactness and lower sigmoid apex height on CTC compared to men (p<0.0001,all). Quantitative measurements in colonic metrics were highly reproducible (ICC=0.9989 and 0.9970; CCC=0.9945). CONCLUSION: Quantitative morphologic differences between genders can be reproducibility measured.

A novel polymeric chlorhexidine delivery device for the treatment of periodontal disease.

An implantable, anti-microbial delivery device for the treatment of periodontal disease has been developed. In this polymer-based delivery system, the encapsulation efficiency, release characteristics, and bioactivity of anti-microbial agent were controlled by the complexation of the drug with cyclodextrins of differing lipophilicity. Microparticles of poly(dl-lactic-co-glycolic acid) (PLGA) containing chlorhexidine (Chx) free base, chlorhexidine digluconate (Chx-Dg) and their association or inclusion complex with methylated-beta-cyclodextrin (MBCD) and hydroxypropyl-beta-cyclodextrin (HPBCD) were prepared by single emulsion, solvent evaporation technique. It was observed that encapsulation efficiency and release of the chlorhexidine derivatives from the microparticles was a function of the lipophilicity of the cyclodextrin. Complexation of the poorly water soluble Chx with the more hydrophilic HPBCD resulted in 62% higher encapsulation efficiency and longer duration of sustained release over a 2-week period than complexation with the more lipophilic MBCD. In contrast, the complexation of the more water-soluble derivative of chlorhexidine, Chx-Dg, with the more lipophilic MBCD improved encapsulation efficiency by 12% and prolonged its release in comparison to both the free Chx-Dg and its complex with HPBCD. Furthermore, it was observed that the initial burst effect could be diminished by complexation with CD. Preliminary studies have shown that the chlorhexidine released from PLGA chips is biologically active against bacterial population that is relevant in periodontitis (P. gingivalis and B. forsythus) and a healthy inhibition zone is maintained in agar plate assay over a period of at least a 1-week. The PLGA/CD delivery system described in this paper may prove useful for the localized delivery of chlorhexidine salts and other anti-microbial agents in the treatment of periodontal disease where prolonged-controlled delivery is desired.