Long-term Hemodialysis Corrects Left Ventricular Dyssynchrony in End-stage Renal Disease: A Study with Gated Technetium-99m Sestamibi Myocardial Perfusion Single-photon Emission Computed Tomography.

INTRODUCTION: Left ventricular (LV) dyssynchrony is common in patients with end-stage renal disease (ESRD), and echocardiographic assessment has shown that it can be improved by a single session of hemodialysis (HD). The aim of this study was to assess the effects of chronic HD on LV dyssynchrony in patients ESRD by means of gated technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography (GSPECT) with phase analysis. MATERIALS AND METHODS: Twelve patients with ESRD underwent GSPECT and echocardiography before the start of long-term HD (baseline) and 3 months later. In addition, 7 control subjects matched for age and sex underwent GSPECT and echocardiography within a 2-month period. To evaluate LV dyssynchrony, both histogram bandwidth (HBW) and phase standard deviation (PSD) were determined with phase analysis of GSPECT images. The end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction were also measured with GSPECT, and the LV mass index (LVMI) was measured with echocardiography. The LV dyssynchrony, volume, function, and mass were compared among control subjects, patients with ESRD at baseline, and patients with ESRD after 3 months of chronic HD. RESULTS: The LV dyssynchrony, volume, and mass at baseline were significantly greater in patients with ESRD than in control subjects (HBW, 65.5°±54.4° vs. 22.3°±7.5°, P<0.05; PSD, 21.0°±15.5° vs. 7.6°±5.5°, P<0.05; EDV, 105.7±29.2 vs. 72.3±13.9 mL, P<0.05; ESV, 44.3±22.1 vs. 20.9±10.3 mL, P<0.05; LVMI, 136.5±48.3 vs. 65.4±5.6 g/m(2), P<0.01). From baseline to the third month of chronic HD, there were significant increases in EDV (78.6±25.4 vs. 105.7±29.2 mL, P<0.01) and ESV (27.6±16.2 vs. 44.3±22.1 mL, P<0.01) and significant decreases in HBW (65.5°±54.4° vs. 31.0°±15.7°, P<0.01) and PSD (21.0°±15.5° vs. 10.0°±8.2°, P<0.01). CONCLUSION: Chronic HD decreased LV dyssynchrony and volume in patients with ESRD. Serial phase analysis of GSPECT images is a useful method of assessing the effects of long-term HD on LV dyssynchrony and volume in patients with ESRD.

Long-lasting narrowing of the parent artery after bilateral clipping of mirror-image aneurysms of distal anterior cerebral arteries: a case report.

Because multiple intracranial aneurysms are not rare, accurate preoperative detection of asymptomatic aneurysms is important. In this paper, we report a ruptured distal anterior cerebral artery (DACA) aneurysm associated with an unruptured mirror-image aneurysm in a 62-year-old man presenting with headache. Although delayed vasospasm after subarachnoid hemorrhage has been reported to persist for 2 to 3 weeks, angiographic parent artery narrowing was far more prolonged in our case. Computed tomography revealed a subarachnoid hemorrhage in the interhemispheric and right sylvian fissures and a right frontal lobe hematoma. Digital subtraction angiography demonstrated bilateral symmetric saccular aneurysms of DACAs. On the day of admission, both aneurysms were clipped using an interhemispheric approach in a one-stage procedure, and the hematoma was aspirated. Angiography performed 8 days after the surgery demonstrated a residual aneurysm neck on the left side. Follow-up digital subtraction angiography performed on day 42 from onset showed resolution of the residual aneurysm neck along with narrowing of the left A2. However, at 7 months, the A2 narrowing had lessened. The location of the bilateral aneurysms near the midline facilitated a single approach but necessitated the application of juxtaposed clips. Regarding the pathogenesis of the bilateral aneurysms, previous reports have suggested symmetry of congenital anatomic defects and hemodynamic stress as potential causes. The persistent narrowing that was observed could have resulted from proliferative vasculopathy or from fibrosis possibly induced by the clips.

Elevation of growth hormone-releasing hormone receptor messenger ribonucleic acid expression in growth hormone-secreting pituitary adenoma with Gsalpha protein mutation.

Growth hormone-releasing hormone (GHRH) stimulates not only the synthesis and secretion of GH but also the proliferation of normal somatotrophs. The expression of GHRH receptor (GHRHR) is regulated by GHRH, both of which are known to be expressed in human GH-secreting pituitary adenoma cells. Somatic mutations in the subunit of Gsalpha protein (gsp), lead to the constitutive activation of adenylyl cyclase in pituitary adenomas that secrete GH. It has not been examined how gsp mutations influence GHRHR expression in GH-secreting adenomas. We therefore analyzed the expression levels of GHRHR messenger ribonucleic acid (mRNA) in GH-secreting pituitary adenomas focusing on a gsp mutation. Furthermore, we investigated the effect of GHRH on the expression of GHRHR mRNA in primary cultures of GH-secreting pituitary adenoma cells. GHRHR mRNA expression levels were significantly elevated in gsp mutation-positive GH-secreting adenomas compared with those in gsp mutation-negative ones. In primary-cultured GH-secreting adenoma cells, the increase of GH secretion in response to GHRH was shown in both gsp mutation-positive and -negative adenoma cells with a significantly higher response in the latter adenoma cells. GHRH increased GHRHR mRNA expression level in gsp mutation-negative adenoma cells while it was not influenced by GHRH in gsp mutation-positive adenoma cells. These results suggest that gsp mutations up-regulate GHRHR mRNA expression in GH-secreting pituitary adenoma cells, and that gsp mutations desensitize the adenoma cells to GHRH in terms of their GHRHR mRNA expression probably because of their saturation of GHRH signaling.

Expression patterns of claudin family of tight-junction proteins in the mouse prostate.

Claudins are the transmembrane proteins forming the backbone of tight junctions, and consist of over 20 members of a gene family. Claudins are expressed in a tissue- and cell-type specific fashion, and changes in their abundance and/or distribution are proposed to play important roles in the pathophysiology of numerous disorders. In the prostate, claudin-1, -3, -4 and -7 transcripts are known to be expressed, but it is unknown regarding mRNA expression of other claudins or concerning expression and localization of claudin proteins in this organ. We herein show, by RT-PCR and Western blotting analyses, that not only these four claudins but also claudin-5, -8 and -10 are expressed in the normal mouse prostate. Claudin-3, -4, -5, -8 and -10 were primarily localized at the apicalmost sites of lateral membranes of luminal epithelial cells in the prostate gland, whereas claudin-1 and -7 were distributed along the basolateral membranes of the epithelium. These findings provide basic information for elucidating the significance of claudins in prostate diseases, including prostate cancers.

The nuclear receptor hepatocyte nuclear factor 4alpha acts as a morphogen to induce the formation of microvilli.

Microvilli are actin-based organelles found on apical plasma membranes that are involved in nutrient uptake and signal transduction. Numerous components, including ezrin/radixin/moesin (ERM) proteins, have been identified that link filamentous actins to transmembrane proteins, but the signals driving microvillus biogenesis are not known. In this study, we show that the conditional and/or ectopic expression of a nuclear receptor, hepatocyte nuclear factor 4alpha (HNF4alpha), triggers microvillus morphogenesis. We also demonstrate that HNF4alpha expression induces ERM-binding phosphoprotein 50 (EBP50) expression and that attenuation of EBP50 using RNA interference inhibits microvillus development. We conclude that HNF4alpha acts as a morphogen to trigger microvillus formation.

Differential expression and subcellular localization of claudin-7, -8, -12, -13, and -15 along the mouse intestine.

Among tight-junction proteins, claudins, which play a key role in paracellular transport across epithelia, claudins 1 to 5 are expressed in the intestine, and changes in their abundance and/or distribution are considered to contribute to various gastrointestinal diseases. We investigated, by reverse transcription-PCR, immunoblot, and immunofluorescence analyses, which other claudin species were expressed in the mouse intestine, and whether they showed unique expression profiles. Rabbit polyclonal antibodies against mouse claudin-8, claudin-12, and claudin-15 were generated, and their specificity was verified by immunoblotting using COS-7 cells transfected with individual claudin cDNAs. Claudin-7, -8, -12, -13, and -15 appeared to be expressed in the duodenum, jejunum, ileum, and/or colon with remarkable variations in the expression levels along the intestinal tract, and had distinct subcellular localization in the intestinal epithelium. In addition, claudin-13 and -15 exhibited gradients along the crypt-surface axis of the colon. By contrast, claudin-6, -9, -10, -11, -14, -16, -18, and -19 were not observed in the intestine. Our results indicate that five additional species of claudins have very complex expression patterns along and within the intestine, and that this may reflect differences in paracellular permeable properties, providing valuable resources for studying the significance of these claudins in gastrointestinal disorders. This manuscript contains online supplemental material available at http://www.jhc.org. Please visit this article online to view these materials.

Activation of p21CIP1/WAF1 gene expression and inhibition of cell proliferation by overexpression of hepatocyte nuclear factor-4alpha.

The F9 murine embryonal carcinoma cell line provides an attractive system for studying epithelial differentiation and antiproliferative processes. We have recently established F9 cells expressing doxycycline-inducible hepatocyte nuclear factor (HNF)-4alpha and shown that HNF-4alpha triggers the gene expression of tight-junction molecules, occludin, claudin-6, and claudin-7, as well as formation of functional tight junctions and polarized epithelial morphology (Exp. Cell Res. 286, [2003] 288). Since these events were very similar to those induced by retinoids, we investigated whether HNF-4alpha, like retinoid receptors, was involved in the control of cell proliferation. We herein show that HNF-4alpha up-regulates expression of the p21 gene, but not the p15, p16, p18, p19, or p27 gene, in a p53-independent manner, and inhibits cell growth in F9 cells. Similar results were observed in rat lung endothelial cells, in which expression of HNF-4alpha is conditionally induced by doxycycline. Furthermore, we demonstrate, by reporter assay, that HNF-4alpha significantly elevates the transcriptional activity of the p21 promoter. Since, HNF-4alpha is expressed not only in the liver but also in organs containing epithelial cells, such as kidney, intestine, pancreas, and stomach, it might also play critical roles in the regulation of epithelial morphogenesis and proliferation in these organs.

Non-traditional roles of ubiquitin-proteasome system in fertilization and gametogenesis.

Fertilization and gametogenesis are key events in sexual reproduction. Our recent studies, together with several reports by other authors, demonstrated that the extracellular ubiquitin-proteasome system plays a role in fertilization and gametogenesis in addition to the traditional intracellular ubiquitin-proteasome system. Here, we summarize our recent results showing the importance of the extracellular ubiquitin-proteasome system in the sperm penetration through the vitelline coat of the egg during ascidian fertilization, together with our recent reports implicating the participation of a novel proteasome-associating complex PC530 in starfish oocyte maturation. We also describe the results by other authors showing the participation of the ubiquitin system both in the elimination of defective sperm in epididymis and in the elimination of paternal mitochondria in fertilized eggs. These are evidence of non-traditional extracellular functions of the ubiquitin system.

Extracellular ubiquitin system implicated in fertilization of the ascidian, Halocynthia roretzi: isolation and characterization.

The ubiquitin-proteasome system is essential for intracellular protein degradation, but there are few studies of this system in the extracellular milieu. Recently, we reported that a 70-kDa sperm receptor, HrVC70, on the vitelline coat is ubiquitinated and then degraded by the sperm proteasome during fertilization of the ascidian, Halocynthia roretzi. Here, we investigated the mechanism of extracellular ubiquitination. The HrVC70-ubiquitinating enzyme activity was found to be released from the activated sperm during the fertilization process. This enzyme was purified from an activated sperm exudate, by chromatography on DEAE-cellulose and ubiquitin-agarose columns, and by glycerol density gradient centrifugation. The molecular mass of the enzyme was estimated to be 700 kDa. The purified enzyme requires CaCl2 and MgATP for activity, and is active in seawater. The purified enzyme preparation, but not the crude enzyme preparation, showed narrow substrate specificity to HrVC70. Moreover, ATP and ubiquitin are released from the activated sperm to the surrounding seawater during fertilization. These results indicate that ascidian sperm release a novel extracellular ubiquitinating enzyme system together with ATP and ubiquitin during penetration of the vitelline coat of the egg, which catalyzes the ubiquitination of the HrVC70, an essential component of ascidian fertilization.

Blood patch therapy for spontaneous intracranial hypotension: safe performance after epidurography in an unconscious patient.

IMPLICATIONS: Epidurography was useful for identifying the epidural space and determining the likely spread of an epidural blood patch in an unconscious patient with spontaneous intracranial hypotension.

Extracellular ubiquitination and proteasome-mediated degradation of the ascidian sperm receptor.

The ubiquitin-proteasome system is essential for intracellular protein degradation, but an extracellular role of this system has not been known until now. We have previously reported that the proteasome is secreted into the surrounding seawater from sperm of the ascidian (Urochordata) Halocynthia roretzi on sperm activation, and that the sperm proteasome plays a key role in fertilization. Here, we show that a 70-kDa component (HrVC70) of the vitelline coat is the physiological substrate for the ubiquitin-proteasome system during fertilization of H. roretzi. A cDNA clone encoding the HrVC70 precursor (HrVC120) was isolated, and a homology search revealed that HrVC120 contains 13 epidermal growth factor-like repeats and a mammalian zona pellucida glycoprotein-homologous domain. HrVC70 functions as a sperm receptor. We demonstrate that HrVC70 is ubiquitinated both in vitro and in vivo. The immunocytochemical localization of multiubiquitin chains in the vitelline coat and the inhibitory effect of monoclonal antibodies against the multiubiquitin chains on fertilization strongly support the role of the ubiquitin-proteasome system in ascidian fertilization. Taken together, these results indicate that the ubiquitin-proteasome system is responsible for extracellular degradation of the sperm receptor HrVC70 and, consequently, for sperm penetration of the vitelline coat during fertilization.