Impaired renal Na(+) retention in the sgk1-knockout mouse

The serum- and glucocorticoid-regulated kinase (sgk1) is induced by mineralocorticoids and, in turn, upregulates heterologously expressed renal epithelial Na(+) channel (ENaC) activity in Xenopus oocytes. Accordingly, Sgk1 is considered to mediate the mineralocorticoid stimulation of renal ENaC activity and antinatriuresis. Here we show that at standard NaCl intake, renal water and electrolyte excretion is indistinguishable in sgk1-knockout (sgk1(-/-)) mice and wild-type (sgk1(+/+)) mice. In contrast, dietary NaCl restriction reveals an impaired ability of sgk1(-/-) mice to adequately decrease Na(+) excretion despite increases in plasma aldosterone levels and proximal-tubular Na(+) and fluid reabsorption, as well as decreases in blood pressure and glomerular filtration rate.     

Ultrasonography of the accessory nerve: normal and pathologic findings in cadavers and patients with iatrogenic accessory nerve palsy.

OBJECTIVE: To determine feasibility of ultrasonography in detecting the normal accessory nerve as well as pathologic changes in cases of accessory nerve palsy. METHODS: Four patients with accessory nerve palsy were investigated by ultrasonography. Three cases of accessory nerve palsy after lymph node biopsy and neck dissection were primarily diagnosed on the basis of ultrasonography using a 5- to 12-MHz linear transducer. In addition, we performed ultrasonography in 3 cadaveric specimens to show the feasibility of detecting the accessory nerve. RESULT: Nerve transection (n = 2), scar tissue (n = 1), and atrophy of the trapezius muscle (n = 4) were confirmed by electroneurographic testing and surgical nerve inspection. In 1 case in which a patient had a whiplash injury with accessory nerve palsy, ultrasonography showed atrophy of the trapezius muscle with a normal nerve appearance. CONCLUSIONS: Ultrasonography allows visualization of the normal accessory nerve as well as changes after accessory nerve palsy.     

Nontumorous vascular malformations in the liver: color Doppler ultrasonographic findings.

OBJECTIVE: To investigate color Doppler and spectral wave characteristics of nontumorous vascular malformations in the liver. METHODS: From September 1995 to January 2001, 32 cases of vascular malformations were identified by means of color Doppler ultrasonography and spectral wave analysis. Computed tomography, angiography, or both were performed in all cases. RESULTS: Five arterioportal and 14 portovenous malformations, 1 arteriovenous malformation, and 4 portoportal and 8 venovenous shunts were detected. Associations with Rendu-Osler-Weber syndrome in 6 cases and with cirrhotic liver in 12 cases were found Fourteen patients were liver disease free. In 3 cases, interventional procedures were necessary to reduce portal hypertension or cardiac dysfunction. The incidence of finding vascular malformations in 12,000 patients was 0.1%. CONCLUSIONS: Nontumorous vascular malformations are rare disorders in the liver. They may appear in patients with healthy livers and in patients with portal hypertension. Color Doppler ultrasonography and spectral wave analysis are capable of showing and differentiating different types of hepatic vascular malformations.     

Image distortion correction in fMRI: A quantitative evaluation

A well-recognized problem with the echo-planar imaging (EPI) technique most commonly used for functional magnetic resonance imaging (fMRI) studies is geometric distortion caused by magnetic field inhomogeneity. This makes it difficult to achieve an accurate registration between a functional activation map calculated from an EPI time series and an undistorted, high resolution anatomical image. A correction method based on mapping the spatial distribution of field inhomogeneities can be used to reduce these distortions. This approach is attractive in its simplicity but requires postprocessing to improve the robustness of the acquired field map and reduce any secondary artifacts. Furthermore, the distribution of the internal magnetic field throughout the head is position dependent resulting in an interaction between distortion and head motion. Therefore, a single field map may not be sufficient to correct for the distortions throughout a whole fMRI time series. In this paper we present a quantitative evaluation of image distortion correction for fMRI at 2T. We assess (i) methods for the acquisition and calculation of field maps, (ii) the effect of image distortion correction on the coregistration between anatomical and functional images, and (iii) the interaction between distortion and head motion, assessing the feasibility of using field maps to reduce this effect. We propose that field maps with acceptable noise levels can be generated easily using a dual echo-time EPI sequence and demonstrate the importance of distortion correction for anatomical coregistration, even for small distortions. Using a dual echo-time series to generate a unique field map at each time point, we characterize the interaction between head motion and geometric distortion. However, we suggest that the variance between successively measured field maps introduces additional unwanted variance in the voxel time-series and is therefore not adequate to correct for time-varying distortions.     

Intrahepatic abscess due to gallbladder perforation

Background Perforation of the gallbladder with cholecystohepatic communication is a rare cause of liver abscess. We report four cases of this condition and describe the imaging procedures related to its diagnosis and treatment.Methods The medical and x-ray files of 39 patients with percutaneous drainage of liver abscesses were retrospectively reviewed. Four patients with hepatic abscess due to gallbladder perforation were identified. The patients presented with clinical features suggestive of cholecystitis.Results Sonography in four patients showed a hypoechoic lesion in the liver adjacent to the gallbladder. CT in three patients showed a hypodense area in the liver, corresponding to the sonographic findings. Percutaneous abscess drainage, followed by an abscessogram, was performed in all patients. Contrast material injected throuugh the drainage catheter filled the gallbladder directly from the abscess cavity. Two patients subsequently underwent cholecystectomy, confirming perforation of the gallbladder fundus. In both cases the gallbladder was noted to be embedded in the liver and covered by adhesions.Conclusion Perforation of the gallbladder is a rare cause of pyogenic liver abscess. We suggest, however, based on our two patients who underwent surgery, and several cases reported in the literature, that this condition may be more common when the gallbladder is partially or totally intrahepatic.     

Spreading Cerebral Oligemia in Classical- and Normal Cerebral Blood Flow in Common Migraine

SYNOPSIS
Regional cerebral blood flow was studied with intra-arterial ¹³³Xenon technique in 254 areas of a hemisphere during the development of classical migraine attacks in seven patients. We describe a gradual spread of reduced cerebral blood flow starting at the posterior pole of the hemisphere and advancing in a mode quite similar to the spreading depression phenomenon of Leao. In three patients the oligemia was preceeded by focal or perifocal hyperemia. Functional activation by speech etc. was usually impaired or abolished during prodromes or accompaniments. Headache was found concommitantly with cerebral blood flow reduction and cannot be caused by reactive hyperemia in these patients. Similar findings were made in two patients studied with tomographic ¹³³Xenon technique. During induced common migraine attacks repeated cerebral blood flow studies with stationary detectors (N =3) and with tomographic technique (N =4) revealed no alterations of global or cerebral blood flow. Also tomographic determination of spontaneous common migraine attacks in four patients was normal. It is concluded that the two forms of migraine are different with respect to cerebral blood flow abnormalities and that they should be studied separately in the future. Greater interest should be directed towards the phenomenon of spreading depression as a possible model of the classical migraine attack.     

Clinical trial of Nimodipine for single attacks of classic migraine

In a randomized, double-blind cross-over study, 43 patients with classic migraine received 40 mg Nimodipine and placebo as sublingual capsules. There was no significant effect on patients' preference, development of headache, need for escape medicine, duration of headache, severity of headache or headache index. Considerable methodological problems were encountered. Only 54% of the 79 patients selected for the trial could be evaluated. Suggestions for future trials are made.