Feasibility of diffusion and probabilistic white matter analysis in patients implanted with a deep brain stimulator

Deep brain stimulation (DBS) for Parkinson's disease (PD) is an established advanced therapy that produces therapeutic effects through high frequency stimulation. Although this therapeutic option leads to improved clinical outcomes, the mechanisms of the underlying efficacy of this treatment are not well understood. Therefore, investigation of DBS and its postoperative effects on brain architecture is of great interest. Diffusion weighted imaging (DWI) is an advanced imaging technique, which has the ability to estimate the structure of white matter fibers; however, clinical application of DWI after DBS implantation is challenging due to the strong susceptibility artifacts caused by implanted devices. This study aims to evaluate the feasibility of generating meaningful white matter reconstructions after DBS implantation; and to subsequently quantify the degree to which these tracts are affected by post-operative device-related artifacts. DWI was safely performed before and after implanting electrodes for DBS in 9 PD patients. Differences within each subject between pre- and post-implantation FA, MD, and RD values for 123 regions of interest (ROIs) were calculated. While differences were noted globally, they were larger in regions directly affected by the artifact. White matter tracts were generated from each ROI with probabilistic tractography, revealing significant differences in the reconstruction of several white matter structures after DBS. Tracts pertinent to PD, such as regions of the substantia nigra and nigrostriatal tracts, were largely unaffected. The aim of this study was to demonstrate the feasibility and clinical applicability of acquiring and processing DWI post-operatively in PD patients after DBS implantation. The presence of global differences provides an impetus for acquiring DWI shortly after implantation to establish a new baseline against which longitudinal changes in brain connectivity in DBS patients can be compared. Understanding that post-operative fiber tracking in patients is feasible on a clinically-relevant scale has significant implications for increasing our current understanding of the pathophysiology of movement disorders, and may provide insights into better defining the pathophysiology and therapeutic effects of DBS.

Impact of pharmaceutical excipients on in vitro association of saquinavir to chylomicrons

This study was performed to investigate the impact of pharmaceutical excipients commonly used for lymphatic transport on in vitro drug association with chylomicrons (CM). A CM association study was conducted using saquinavir solubilized in four different pharmaceutical excipients. We observed a linear relationship between saquinavir solubility and drug association, suggesting that the solubility of saquinavir in excipients is a key determinant for successful lymphatic delivery. Broadly, these results suggest that excipients with good solubilization properties may be advantageous for enhancing lymphatic drug delivery.

Phase II prevention trial of celecoxib in women at increased risk for breast cancer

1501

Background: Tamoxifen and raloxifen reduce the risk of estrogen receptor (ER) positive breast cancer. Acceptance of SERMs is low due to toxicities. New agents with a better toxicity profile which also will prevent ER-negative breast cancer are needed. The cyclooxygenase II inhibitor celecoxib has antiproliferative, and antiangiogenetic properties and is a putative breast cancer prevention agent. Our objective in this prospective short-term prevention study was to evaluate the effect of celecoxib on biomarkers in breast tissue and serum of high risk women. Methods: High risk individuals with a history of atypical hyperplasia, or lobular carcinoma insitu, or Gail risk greater than 1.67%, or previous history of ER negative breast cancer were eligible. After signing informed consent subjects underwent baseline fine needle aspiration (FNA) of the breast and serum collection for biomarker analysis. Subjects started celecoxib at 400 mg po BID for 6 months and underwent repeat FNA and serum collection. Biomarker endpoints included changes in ER and KI-67 expression in breast tissue analyzed by immunohistochemistry and insulin like growth factor binding protein (IGFBP-1) in serum analyzed by ELISA. The difference in biomarkers before and after treatment was assessed using a Wilcoxon signed rank test. Results: 49 patients were enrolled and accrual has been completed. Median age was 51 years and 57% of women were postmenopausal. The mean pre- and post treatment ER expression was 35.5% and 31%, respectively. The difference in ER expression was not significant (p = 0.1). The mean pre- and post treatment KI-67 expression was 1.68% and 1.60%, respectively. The difference was not significant (p = 0.8). However, there was a statistically significant difference in pre- and post treatment IGFBP-1 levels (p=0.023), with pre-and post treatment levels being 6.81ng/ml and 11.51ng/ml, respectively. No grade 3 or 4 toxicities were observed and there was no drop-out from the study. Conclusions: We have found a significant modulation of IGFBP-1 levels with 6 months celecoxib treatment in women who are at increased risk of developing breast cancer. The acceptable side effect profile and modulation of the biomarker (IGFBP-1) provides support for continued evaluation of celecoxib as a breast cancer prevention agent.

No significant financial relationships to disclose.

Turmeric (Curcuma longa) and curcumin inhibit the growth of Helicobacter pylori, a group 1 carcinogen

BACKGROUND

Curcumin, a polyphenolic chemical constituent derived from turmeric (Curcuma longa), has been shown to prevent gastric and colon cancers in rodents. Many mechanisms have been proposed for the chemopreventative effects, although the effect of curcumin on the growth of Helicobacter pylori has not been reported. H. pylori is a Group 1 carcinogen and is associated with the development of gastric and colon cancer.

MATERIALS AND METHODS

A methanol extract of the dried powdered turmeric rhizome and curcumin were tested against 19 strains of H. pylori, including 5 cagA+ strains.

RESULTS

Both the methanol extract and curcumin inhibited the growth of all strains of H. pylori in vitro with a minimum inhibitory concentration range of 6.25-50 micrograms/ml.

CONCLUSION

These data demonstrate that curcumin inhibits the growth of H. pylori cagA+ strains in vitro, and this may be one of the mechanisms by which curcumin exerts its chemopreventative effects.

Intravitreal pharmacokinetics of liposome-encapsulated amikacin in a rabbit model

BACKGROUND

Intravitreal injection of antibiotics has become a standard therapy for bacterial endophthalmitis. The duration of effective antimicrobial levels in the vitreous after single injection, however, may not be long enough to get optimal response. The authors prepared liposome-encapsulated amikacin for prolonging the duration of intravitreal therapeutic concentrations and investigated the intravitreal pharmacokinetics of the liposomes and amikacin in phosphate buffer solution (PBS) as control.

METHODS

The liposome-encapsulated amikacin was prepared by reverse-phase evaporation method. The intravitreal pharmacokinetics of the liposomes was compared with amikacin in PBS by fluorescence polarization immunoassay. Albino rabbits were randomly distributed into 12 groups. Rabbits in groups 1 to 6 and in groups I to VI (control groups) received an intravitreal injection of the liposome-encapsulated amikacin and amikacin in PBS, respectively.

RESULTS

The encapsulation rate of amikacin was 91%. The time of 50% spontaneous degradation (half-life) of the liposomes in PBS (38 degrees C, pH 7.4) was 47.6 days, and the time of 50% release (half-life) of the drug from the liposomes in PBS was 84.8 hours. The vitreous amikacin concentrations in groups 1 to 6 were significantly greater (P < 0.05) than those in control groups I to VI in every time interval, except in groups 1 to 3 at 1 hour after injection. The difference was particularly obvious in the endophthalmitis groups. The clearance of encapsulated amikacin in vitreous appeared to be related to the state of blood-ocular barrier and to the structural integrity of vitreous. The distribution, the absorption, and the elimination of encapsulated amikacin in vitreous showed the first-order kinetics.

CONCLUSION

The liposome-encapsulated amikacin prolonged half-life of the drug in vitreous. The results of the pharmacokinetic analysis suggested that in endophthalmitis, especially in severe cases, the liposomes may be preferable to conventional preparation.

[Causes of death and prognosis of myocardial infarction in patients with diabetes]

The long-term prognosis and causes of death of myocardial infarction (MI) in 62 patients with diabetes were studied. The mean follow-up time was 6.2 years. 11 cases died in the acute period of MI (8 weeks following onset of AMI), 9 cases of them (81.8%) had anterior infarction and their major causes of death were ventricular fibrillation and cardiogenic shock (72.2%). 19 cases died in the follow-up period, among them 14 cases (73.68%) had inferior and anterior-septal infarction; most of them died of reinfarction and sudden death. The cumulative survival rate 1.2 and 5 years after MI was 80.7%, 71.9% and 57.9%, respectively. The blood glucose level of the fatal group and the level of CPK and GOT of patients who died in the acute period were higher than those in the surviving group. The results suggest that treatment of myocardial infarction in patients with diabetes be more attentive to prevent ventricular fibrillation and cardiogenic shock during the acute period. After the acute period more attention should be paid to prevent reinfarction and and drop the blood glucose level at normal as possible.