Clinical assessment of three-dimensional ultrasound prostate localization for external beam radiotherapy

Three-dimensional ultrasound localization has been performed for external beam prostate treatments at our institution since September 2001. This article presents data from the daily shifts for 221 patients and 5005 fractions, and the results of tests performed to assess the system's performance under clinical conditions. Three tests are presented: (1) To measure the accuracy of the shifts, eight patients treated on a helical tomotherapy machine were localized daily using both ultrasound (US) and a megavoltage computed tomography (MVCT) scan. Comparison of the shifts showed that US localization improved alignment for six of the eight patients when compared to alignment using skin marks alone. The mean US-MVCT vector for these six patients was 3.1+/-1.3 mm, compared to 5.1+/-2.1 mm between the MVCT and the skin marks. The other two patients were identified as poor candidates for US prior to their first treatment fraction. (2) To assess the extent of intrafraction motion, US localization was repeated after treatment for six patients and a total of 29 fractions. The mean intrafraction prostate shift was 1.9+/-1.0 mm, and the shift was within the 3 mm localization uncertainty [Tomé et al., Med. Phys. 29, 1781-1788 (2002); in New Technologies in Radiation Oncology, edited by W. Schlegel, T. Bortfelde, and A. Grosu (Springer, Berlin, 2005)] of the system for 25 of 29 fractions. (3) To assess the interuser variation in shifts, four experienced operators independently localized five patients for five consecutive fractions. The standard deviation of the users' shifts was found to be approximately the same as the system's localization uncertainty. For shifts larger than the system localization uncertainty, the standard deviation of the users' shifts was nearly always much smaller than the mean shift. Taken together with the results of the US-MVCT comparison, this indicates that the shifts improved patient localization despite differences between users.     

The uroguanylin system and human disease

The uroguanylin system is a newly discovered endocrine/paracrine system that may have a role in the regulation of salt balance, appetite and gut health. The precursor pro-uroguanylin is predominantly synthesized in the gut, although there may be other sites of synthesis, including the kidney tubules. Products from pro-uroguanylin may mediate natriuresis following oral consumption of a salt load through both GC-C (guanylate cyclase C)-dependent and -independent mechanisms, and recent evidence suggests a role in appetite regulation. Local paracrine effects in the gut through GC-C stimulation may have tumour-suppressing actions through the regulation of cell proliferation and metabolism. Although most information on this system has been derived from knockout models, recent human studies have indicated possible roles in heart failure and renal failure. An improved understanding of the nature of its natriuretic, appetite and tumour-suppressing actions may facilitate the discovery of new therapies for heart failure, obesity and cancer prophylaxis.     

Comparison of the prognostic value of F-18 FDG PET/CT metabolic parameters of primary tumors and MRI findings in patients with locally advanced cervical cancer treated with concurrent chemoradiotherapy

Purpose

To evaluate the effect of metabolic parameters of pretreatment primary tumor and regional lymph nodes with F-18-FDG PET/CT compared with MRI findings for the prognostic value and disease-free survival (DFS) in locally advanced cervical cancer.

Inhibition of Ang II and renal sympathetic nerve influence dopamine-and isoprenaline-induced renal haemodynamic changes in normal Wistar-Kyoto and spontaneously hypertensive rats

1. This study was undertaken to elucidate the effects of inhibiting the renin-angiotensin system (RAS) with losartan, and acute unilateral renal denervation on renal haemodynamic responses to intrarenal administration of vasoconstrictor doses of dopamine and vasodilator doses of isoprenaline in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). 2. Acute unilateral renal denervation of the left kidney in rats was confirmed by a drop in the renal vasoconstrictor response to renal nerve stimulation (P < 0.05) along with diuresis and natriuresis. Rats were pretreated with losartan for 7 days and thereafter animals fasted overnight were anaesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and acute renal haemodynamic responses studied. 3. Dose-response curves were constructed for dopamine and isoprenaline that induced falls or increases in renal blood flow, respectively. It was observed that renal vascular responses were greater in the denervated as compared with rats with intact renal nerves (all P < 0.05). Dopamine-induced renal vasoconstrictor responses were markedly lower in losartan-treated denervated WKY and SHR compared with their untreated counterparts (all P < 0.05). It was also observed that in losartan-treated and denervated WKY rats the vasodilatory responses to isoprenaline were markedly lower compared with untreated rats (all P < 0.05). However, in SHR, under the same conditions, there was no difference in the renal response to isoprenaline whether or not rats were treated with losartan (P > 0.05). 4. The data obtained showed that the renal vasoconstrictor effect of dopamine depends on intact renal nerves and RAS in WKY and SHR. Isoprenaline responses were likewise sensitive to renal denervation and RAS inhibition in WKY rats but not SHRs. Our observations reveal a possible relationship between renal AT(1) receptors and alpha(1)-adrenoceptors in WKY and SHR. There is also evidence to suggest an interaction between renal beta-adrenoceptors and AT(1) receptors in WKY rats.     

Expression of myogenic regulatory factors in chicken embryos during somite and limb development

The expression of the myogenic regulatory factors (MRFs), Myf5, MyoD, myogenin (Mgn) and MRF4 have been analysed during the development of chicken embryo somites and limbs. In somites, Myf5 is expressed first in somites and paraxial mesoderm at HH stage 9 followed by MyoD at HH stage 12, and Mgn and MRF4 at HH stage 14. In older somites, Myf5 and MyoD are also expressed in the ventrally extending myotome prior to Mgn and MRF4 expression. In limb muscles a similar temporal sequence is observed with Myf5 expression detected first in forelimbs at HH stage 22, MyoD at HH stage 23, Mgn at HH stage 24 and MRF4 at HH stage 30. This report describes the precise time of onset of expression of each MRF in somites and limbs during chicken embryo development, and provides a detailed comparative timeline of MRF expression in different embryonic muscle groups.