Nuclear calcium signaling evoked by cholinergic stimulation in hippocampal CA1 pyramidal neurons

The cholinergic system is thought to play an important role in hippocampal-dependent learning and memory. However, the mechanism of action of the cholinergic system in these actions in not well understood. Here we examined the effect of muscarinic receptor stimulation in hippocampal CA1 pyramidal neurons using whole-cell recordings in acute brain slices coupled with high-speed imaging of intracellular calcium. Activation of muscarinic acetylcholine receptors by synaptic stimulation of cholinergic afferents or application of muscarinic agonist in CA1 pyramidal neurons evoked a focal rise in free calcium in the apical dendrite that propagated as a wave into the soma and invaded the nucleus. The calcium rise to a single action potential was reduced during muscarinic stimulation. Conversely, the calcium rise during trains of action potentials was enhanced during muscarinic stimulation. The enhancement of free intracellular calcium was most pronounced in the soma and nuclear regions. In many cases, the calcium rise was distinguished by a clear inflection in the rising phase of the calcium transient, indicative of a regenerative response. Both calcium waves and the amplification of action potential-induced calcium transients were blocked the emptying of intracellular calcium stores or by antagonism of inositol 1,4,5-trisphosphate receptors with heparin or caffeine. Ryanodine receptors were not essential for the calcium waves or enhancement of calcium responses. Because rises in nuclear calcium are known to initiate the transcription of novel genes, we suggest that these actions of cholinergic stimulation may underlie its effects on learning and memory.

Magnetization transfer imaging for polymer gel dosimetry

Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acryl ate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo read-out with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found to be negligible under the prevailing experimental conditions. The usefulness of MT imaging was assessed by computing the dose resolution obtained with this technique. We found a low value of dose resolution over a wide range of doses could be obtained with a single experiment. This is an advantage over multiple spin echo (MSE) experiments using a single echo spacing where an optimal dose resolution is achieved over only very limited ranges of doses. The results suggest MT imaging protocols may be developed into a useful tool for polymer gel dosimetry.

Finite-difference time-domain-based studies of MRI pulsed field gradient-induced eddy currents inside the human body

In modern magnetic resonance imaging (MRI), patients are exposed to strong, rapidly switching magnetic gradient fields that, in extreme cases, may be able to elicit nerve stimulation. This paper presents theoretical investigations into the spatial distribution of induced current inside human tissues caused by pulsed z-gradient fields. A variety of gradient waveforms have been studied. The simulations are based on a new, high-definition, finite-difference time-domain method and a realistic inhomogeneous 10-mm resolution human body model with appropriate tissue parameters. it was found that the eddy current densities are affected not only by the pulse sequences but by many parameters such as the position of the body inside the gradient set, the local biological material properties and the geometry of the body. The discussion contains a comparison of these results with previous results found in the literature. This study and the new methods presented herein will help to further investigate the biological effects caused by the switched gradient fields in a MRI scan. (C) 2002 Wiley Periodicals, Inc.

Sodium channel alpha 1-subunit mutations in severe myoclonic epilepsy of infancy and infantile spasms

Background: Mutations in SCN1A, the gene encoding the alpha1 subunit of the sodium channel, have been found in severe myoclonic epilepsy of infancy (SMEI) and generalized epilepsy with febrile seizures plus (GEFS(+)). Mutations in SMEI include missense, nonsense, and frameshift mutations more commonly arising de novo in affected patients. This finding is difficult to reconcile with the family history of GEFS(+) in a significant proportion of patients with SMEI Infantile spasms (IS), or West syndrome, is a severe epileptic encephalopathy that is usually symptomatic. In some cases, no etiology is found and there is a family history of epilepsy. Method: The authors screened SCN1A in 24 patients with SMEI and 23 with IS. Results: Mutations were found in 8 of 24 (33%) SMEI patients, a frequency much lower than initial reports from Europe and Japan. One mutation near the carboxy terminus was identified in an IS patient. A family history of seizures was found in 17 of 24 patients with SMEI. Conclusions: The rate of SCN1A mutations in this cohort of SMEI patients suggests that other factors may be important in SMEI. Less severe mutations associated with GEFS(+) could interact with other loci to cause SMEI in cases with a family history of GEFS(+). This study extends the phenotypic heterogeneity of mutations in SCN1A to include IS.

A New Family of Distance Functions for Perceptual Similarity Retrieval of Medical Images

A long-standing challenge of content-based image retrieval (CBIR) systems is the definition of a suitable distance function to measure the similarity between images in an application context which complies with the human perception of similarity. In this paper, we present a new family of distance functions, called attribute concurrence influence distances (AID), which serve to retrieve images by similarity. These distances address an important aspect of the psychophysical notion of similarity in comparisons of images: the effect of concurrent variations in the values of different image attributes. The AID functions allow for comparisons of feature vectors by choosing one of two parameterized expressions: one targeting weak attribute concurrence influence and the other for strong concurrence influence. This paper presents the mathematical definition and implementation of the AID family for a two-dimensional feature space and its extension to any dimension. The composition of the AID family with L (p) distance family is considered to propose a procedure to determine the best distance for a specific application. Experimental results involving several sets of medical images demonstrate that, taking as reference the perception of the specialist in the field (radiologist), the AID functions perform better than the general distance functions commonly used in CBIR.

Constancy check of beam quality in conventional diagnostic X-ray equipment

A tandem ionization chamber was developed for quality control programs of X-ray equipment used in conventional radiography and mammography. A methodology for the use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities was established. The application at a medical X-ray imaging facility of this established methodology is presented. The use of the tandem chamber in the constancy check of diagnostic X-ray beam qualities is a useful method to control the performance of the X-ray equipment. (c) 2008 Elsevier Ltd. All rights reserved.

Perioperative Temporary Occlusion of the Internal Iliac Arteries as Prophylaxis in Cesarean Section at Risk of Hemorrhage in Placenta Accreta

Purpose The purpose of this study was to describe the preliminary results of prophylactic temporary balloon occlusion of the internal iliac arteries for bleeding control in patients with placenta accreta during cesarean hysterectomy. Methods From May 2006 to March 2010, 21 patients diagnosed with placenta accreta using ultrasound and/or magnetic resonance imaging were submitted to prophylactic balloon occlusion before hysterectomy. Fluoroscopy, balloon occlusion time, surgical duration, intraoperative blood loss, transfusion volume, and procedure complications were analyzed. Results The mean age was 30.5 years with a mean of 3.6 previous gestations. Imaging studies revealed that all patients had placenta accreta and all were submitted to cesarean hysterectomy. One hysterectomy was due to previous diagnosis of fetal death and another due to cesarean with uterine curettage. Mean fluoroscopy time was 7.5 min, balloon occlusion time was 164 min, and surgery duration was 260 min. Estimated blood loss was 1,671.5 ml with mean reposition fluids of 3,538 ml of crystalloids, 309.5 ml of colloids, and 1.24 ml of packed red blood cells. Two patients were submitted to thromboembolectomy due to prolonged surgical time. There was no maternal or fetal mortality related to the procedure. Conclusions The results demonstrated that prophylactic balloon occlusion of internal iliac artery is a safe method and appears to reduce blood loss and transfusion requirements in patients diagnosed with placenta accreta who undergo cesarean hysterectomy. Antenatal imaging diagnosis of placenta accreta enables preoperative planning.

Prostatic Artery Embolization as a Primary Treatment for Benign Prostatic Hyperplasia: Preliminary Results in Two Patients

Symptomatic benign prostatic hyperplasia (BPH) typically occurs in the sixth and seventh decades, and the most frequent obstructive urinary symptoms are hesitancy, decreased urinary stream, sensation of incomplete emptying, nocturia, frequency, and urgency. Various medications, specifically 5-alpha-reductase inhibitors and selective alpha-blockers, can decrease the severity of the symptoms secondary to BPH, but prostatectomy is still considered to be the traditional method of management. We report the preliminary results for two patients with acute urinary retention due to BPH, successfully treated by prostate artery embolization (PAE). The patients were investigated using the International Prostate Symptom Score, by digital rectal examination, urodynamic testing, prostate biopsy, transrectal ultrasound (US), and magnetic resonance imaging (MRI). Uroflowmetry and postvoid residual urine volume complemented the investigation at 30, 90, and 180 days after PAE. The procedure was performed under local anesthesia; embolization of the prostate arteries was performed with a microcatheter and 300- to 500-mu m microspheres using complete stasis as the end point. One patient was subjected to bilateral PAE and the other to unilateral PAE; they urinated spontaneously after removal of the urethral catheter, 15 and 10 days after the procedure, respectively. At 6-month follow-up, US and MRI revealed a prostate reduction of 39.7% and 47.8%, respectively, for the bilateral PAE and 25.5 and 27.8%, respectively, for the patient submitted to unilateral PAE. The early results, at 6-month follow-up, for the two patients with BPH show a promising potential alternative for treatment with PAE.

MR Imaging Findings of Iron Overload

Hemochromatosis can be classified as (a) primary, when it originates from a genetic disturbance that promotes the increase of iron absorption, or (b) secondary, when it relates to chronic diseases or to multiple transfusions. The distribution of iron accumulation differs between these two forms; therefore, they can be distinguished by using imaging methods in the majority of cases. Magnetic resonance (MR) imaging is the most sensitive and specific imaging modality in the diagnosis of hemochromatosis. The susceptibility effect caused by the accumulation of iron leads to signal loss in the affected tissues, particularly with the T2*-weighted sequences, which makes the diagnosis of iron overload possible. By using MR imaging techniques, it is possible to estimate the hepatic iron concentration in a noninvasive way, thereby avoiding repeated biopsies. Hemochromatosis can lead to complications, such as a higher frequency of neoplasia, particularly the development of hepatocellular carcinoma. Other neoplasms, such as colorectal tumors, are also associated. Complications related to the treatment of chronic anemia include the appearance of peliosis hepatis and tumors, which can regress after the suspension of treatment with drugs. Knowledge of the disease and of the patterns of iron deposition in patients with iron overload enables not only diagnosis, but also treatment, follow-up, and the detection of possible complications by using imaging methods. (C) RSNA, 2009 . radiographics.rsna.org

ACHIEVEMENTS AND CHALLENGES OF ISPRM

This paper describes the history of the International Society of Physical and Rehabilitation Medicine (ISPRM) Past achievements. and current challenges are outlined ISPRM has been successful In setting up a central office. attracting individual and national members,. holding International congresses, and establishing relations with the Journal of Rehabilitation Medicine (JRM) as the organization`s official journal ISPRM is currently; In official relations with the World Health Organization (WHO) and collaborates closely, with WHO`s Disability and Rehabilitation team ISPRM, however also faces challenges with regard to its growth and the realization of its goals These Include boundaries of voluntary leadership. limited economic resources, the need for enhancing the central office. variations in membership. limits of the current congress bidding system and structure, relations with regional societies, and the need to further develop policies within the field of Physical and Rehabilitation Medicine (PRM) and In relation to WHO and the United Nations system is concluded that ISPRM must evolve from an organization, of which the main activities ay-e to hold a biennial congress hosted by a member nation and to provide input to WHO on request. Into a professional non-governmental organization (NGO) ISPRA should embark on assuming, a leadership role at the further development of PRM within the broader area of human functioning and rehabilitation

Coronary Artery Stenoses: Accuracy of 64-Detector Row CT Angiography in Segments with Mild, Moderate, or Severe Calcification-A Subanalysis of the CORE-64 Trial

Purpose: To evaluate the influence of cross-sectional arc calcification on the diagnostic accuracy of computed tomography (CT) angiography compared with conventional coronary angiography for the detection of obstructive coronary artery disease (CAD). Materials and Methods: Institutional Review Board approval and written informed consent were obtained from all centers and participants for this HIPAA-compliant study. Overall, 4511 segments from 371 symptomatic patients (279 men, 92 women; median age, 61 years [interquartile range, 53-67 years]) with clinical suspicion of CAD from the CORE-64 multi-center study were included in the analysis. Two independent blinded observers evaluated the percentage of diameter stenosis and the circumferential extent of calcium (arc calcium). The accuracy of quantitative multidetector CT angiography to depict substantial (>50%) stenoses was assessed by using quantitative coronary angiography (QCA). Cross-sectional arc calcium was rated on a segment level as follows: noncalcified or mild (<90 degrees), moderate (90 degrees-180 degrees), or severe (>180 degrees) calcification. Univariable and multivariable logistic regression, receiver operation characteristic curve, and clustering methods were used for statistical analyses. Results: A total of 1099 segments had mild calcification, 503 had moderate calcification, 338 had severe calcification, and 2571 segments were noncalcified. Calcified segments were highly associated (P < .001) with disagreement between CTA and QCA in multivariable analysis after controlling for sex, age, heart rate, and image quality. The prevalence of CAD was 5.4% in noncalcified segments, 15.0% in mildly calcified segments, 27.0% in moderately calcified segments, and 43.0% in severely calcified segments. A significant difference was found in area under the receiver operating characteristic curves (noncalcified: 0.86, mildly calcified: 0.85, moderately calcified: 0.82, severely calcified: 0.81; P < .05). Conclusion: In a symptomatic patient population, segment-based coronary artery calcification significantly decreased agreement between multidetector CT angiography and QCA to detect a coronary stenosis of at least 50%.

Follow-up of endovascular treatment of direct carotid-cavernous fistulas

Direct carotid-cavernous fistula (CCF) is a direct communication between the internal carotid artery (ICA) and the cavernous sinus. Some patients treated with detachable balloons develop pseudoaneurysms or present with a true aneurysm recanalization in the cavernous ICA with poorly known long-term radiological and clinical progression. The objective of the present study was to evaluate the long-term clinical and radiological progression of patients treated with detachable balloons. The present study evaluated 13 patients previously treated for direct CCF by an endovascular approach. The follow-up period ranged between 19 and 128 months. Ophthalmological evaluation demonstrated alterations in eight patients (61.5%). All of these alterations were already present from the moment of the treatment and displayed no signs of progression. Cranial magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed in all patients, and 11 pseudoaneurysms were demonstrated in ten of the 11 patients in whom ICA patency had been preserved. Five patients were submitted for cerebral digital subtraction angiography (DSA) to characterize the pseudoaneurysms previously observed on MRA studies, with no significant differences in morphology, size, aneurismal neck, and number of lesions. Endovascular treatment of direct CCF with detachable balloons has been shown to be a long-term effective and stable therapeutic method. The authors found asymptomatic pseudoaneurysms in 91% of cases where the ICA patency was preserved. MRI and MRA demonstrated an accuracy similar to that of DSA in the diagnosis of pseudoaneurysms of cavernous ICA.

MR Spectroscopy Detects Lipid Peaks in Cerebrotendinous Xanthomatosis

CTX is a rare lipid-storage disease. Novel MRS findings from 3 patients, using a short TE, were the presence of lipid peaks at 0.9 and 1.3 ppm in the depth of the cerebellar hemisphere; this might represent an additional marker of disease that is CNS-specific and noninvasive. A decrease in NAA concentration was also detected and attributed to neuroaxonal damage. One patient presented an increase in mlns concentration, pointing to gliosis and astrocytic proliferation.

Immunohistochemical detection of polyductin and co-localization with liver progenitor cell markers during normal and abnormal development of the intrahepatic biliary system and in adult hepatobiliary carcinomas

The longest open reading frame of PKHD1 (polycystic kidney and hepatic disease 1), the autosomal recessive polycystic kidney disease (ARPKD) gene, encodes a single-pass, integral membrane protein named polyductin or fibrocystin. A fusion protein comprising its intracellular C-terminus, FP2, was previously used to raise a polyclonal antiserum shown to detect polyductin in several human tissues, including liver. In the current study, we aimed to investigate by immunohistochemistry the detailed polyductin localization pattern in normal (ductal plate [DP], remodelling ductal plate [RDP], remodelled bile ducts) and abnormal development of the primitive intrahepatic biliary system, known as ductal plate malformation (DPM). This work also included the characterization of polyductin expression profile in various histological forms of neonatal and infantile cholestasis, and in cholangiocellular carcinoma (CCC) and hepatocellular carcinoma (HCC). We detected polyductin expression in the intrahepatic biliary system during the DP and the RDP stages as well as in DPM. No specific staining was found at the stage of remodelled bile ducts. Polyductin was also detected in liver biopsies with neonatal cholestasis, including mainly biliary atresia and neonatal hepatitis with ductular reaction as well as congenital hepatic fibrosis. In addition, polyductin was present in CCC, whereas it was absent in HCC. Polyductin was also co-localized in some DP cells together with oval stem cell markers. These results represent the first systematic study of polyductin expression in human pathologies associated with abnormal development of intrahepatic biliary tree, and support the following conclusions: (i) polyductin expression mirrors developmental properties of the primitive intrahepatic biliary system; (ii) polyductin is re-expressed in pathological conditions associated with DPM and (iii) polyductin might be a potential marker to distinguish CCC from HCC.

Evaluation of serum trace element, biochemical and hematological data of a healthy elderly group residing in So Paulo city, Brazil

In this study, blood serum trace elements, biochemical and hematological parameters were obtained to assess the health status of an elderly population residing in So Paulo city, SP, Brazil. Results obtained showed that more than 93% of the studied individuals presented most of the serum trace element concentrations and of the hematological and biochemical data within the reference values used in clinical laboratories. However, the percentage of elderly presenting recommended low density lipoprotein (LDL) cholesterol concentrations was low (70%). The study indicated positive correlation between the concentrations of Zn and LDL-cholesterol (p < 0.06).