Radiation induced brain injury: assessment of white matter tracts in a pre-clinical animal model using diffusion tensor MR imaging

We aim to study radiation induced white matter injury in a pre-clinical model using Diffusion tensor MR imaging (DTI). Nineteen 12-week old Sprague–Dawley rats were irradiated to the right hemisphere using a linear accelerator. The dose distribution map was coregistered to the DTI map to generate the actual radiation dose to each white matter tract. Rats underwent longitudinal DTI scans at five time points from 4 to 48 weeks post-radiation with histological evaluations. Fractional anisotropy (FA) of the external capsule, fornix, cerebral peduncle, anterior commissure, optic tract and optic nerve was evaluated. Radiation dose was highest at the ipsilateral external capsule and fornix (29.4 ± 1.3 and 29.8 ± 1.1 Gy, respectively). Optic nerve received 50 % dose to the external capsule and other white matter tracts received 80 % dose. Significantly lower FA was firstly found in the ipsilateral external capsule at 4 weeks post-radiation and in the ipsilateral fornix at 40 weeks post-radiation compared to the contralateral side. Significantly lower FA was found in contralateral optic nerve compared to ipsilateral optic nerve at 48 weeks post-radiation despite ipsilateral optic nerves receiving higher radiation dose than contralateral optic nerve (p = 0.021). No differences were found in other white matter regions until 48 weeks. Histology indicated demyelination, axonal degeneration and coagulative necrosis in all injured white matter. DTI can serve as a promising tool for assessment of radiation induced white matter injury and regional radiosensitivity of white matter tracts.     

Integrating Health Belief Model and Technology Acceptance Model: An Investigation of Health-Related Internet Use

Background

Today, people use the Internet to satisfy health-related information and communication needs. In Malaysia, Internet use for health management has become increasingly significant due to the increase in the incidence of chronic diseases, in particular among urban women and their desire to stay healthy. Past studies adopted the Technology Acceptance Model (TAM) and Health Belief Model (HBM) independently to explain Internet use for health-related purposes. Although both the TAM and HBM have their own merits, independently they lack the ability to explain the cognition and the related mechanism in which individuals use the Internet for health purposes.

Objective

This study aimed to examine the influence of perceived health risk and health consciousness on health-related Internet use based on the HBM. Drawing on the TAM, it also tested the mediating effects of perceived usefulness of the Internet for health information and attitude toward Internet use for health purposes for the relationship between health-related factors, namely perceived health risk and health consciousness on health-related Internet use.

Methods

Data obtained for the current study were collected using purposive sampling; the sample consisted of women in Malaysia who had Internet access. The partial least squares structural equation modeling method was used to test the research hypotheses developed.

Results

Perceived health risk (β=.135, t ₁₉₉₉=2.676) and health consciousness (β=.447, t ₁₉₉₉=9.168) had a positive influence on health-related Internet use. Moreover, perceived usefulness of the Internet and attitude toward Internet use for health-related purposes partially mediated the influence of health consciousness on health-related Internet use (β=.025, t ₁₉₉₉=3.234), whereas the effect of perceived health risk on health-related Internet use was fully mediated by perceived usefulness of the Internet and attitude (β=.029, t ₁₉₉₉=3.609). These results suggest the central role of perceived usefulness of the Internet and attitude toward Internet use for health purposes for women who were health conscious and who perceived their health to be at risk.

Conclusions

The integrated model proposed and tested in this study shows that the HBM, when combined with the TAM, is able to predict Internet use for health purposes. For women who subjectively evaluate their health as vulnerable to diseases and are concerned about their health, cognition beliefs in and positive affective feelings about the Internet come into play in determining the use of health-related Internet use. Furthermore, this study shows that engaging in health-related Internet use is a proactive behavior rather than a reactive behavior, suggesting that TAM dimensions have a significant mediating role in Internet health management.     

Cervical arthroplasty for myelopathy adjacent to previous multisegmental fusion

In recent years, there has been increasing interest in the use of cervical arthroplasty for the treatment of degenerative cervical pathology. In its relative infancy, the applications for this technique are still being explored. In this report, we present the use of cervical arthroplasty in the treatment of progressive cervical myelopathy due to adjacent segment disease related to previous multisegmental fusion.     

Ultrasound contrast agent Levovist in colour Doppler sonography of hepatocellular carcinoma in Chinese patients

In a phase IIIb clinical trial of the ultrasound contrast agent Levovist (Schering AG, Berlin, Germany), the role of Levovist in the management of patients with clinically suspected hepatocellular carcinoma (HCC) was evaluated and its efficacy was assessed. The assessment included the duration of diagnostically usable Doppler signal enhancement, and safety and tolerance of intravenous administration. All patients with clinically suspected hepatocellular carcinoma were referred for Doppler sonographic examination over a 5-month period and lesions with absent or suboptimal Doppler signals were included in the trial. A total of 300 mg/mL in concentration (8.5 mL) of Levovist was administered through a peripheral vein while Doppler signal intensity in the lesion, based on a visual score, was recorded. Blood pressure and pulse were recorded before and after injection. Thirty-eight patients were examined, of which 29 were included in the trial. The lesions were subsequently proven histologically to be 19 HCC, one cholangiocarcinoma, two regeneration nodules and one colonic metastasis. For six patients in whom histological proof was not available, the diagnosis of HCC was suggested based on markedly elevated serum alpha-fetoprotein levels. All but one (96%) of the 25 HCC demonstrated increased Doppler signal after Levovist. There were no Doppler signals before and after Levovist injection in three non-HCC lesions (two regeneration nodules and one colonic metastasis). Two patients (6.9%) suffered minor adverse reactions of nausea and vomiting. The results show that Levovist is safe and is able to improve lesion characterization and increase diagnostic confidence of hepatocellular carcinoma by enhancing tumour vascularization Doppler signal intensity.