Human herpesvirus-8 infection in hemodialysis patients from eastern Taiwan--Hualien

Human herpesvirus-8 (HHV-8) is the causative agent in Kaposi's sarcoma (KS). Uremic or hemodialysis patients are known to be highly susceptible to viral infection, and may be at increased risk of developing KS from the increased risk of exposure to HHV-8 infection. We collected 77 serum samples from hemodialysis patients and 207 serum samples from blood donors. Serum samples were tested for HHV-8-specific immunoglobulin G by immunofluorescence assay. Fifteen of 77 hemodialysis patients (19.5%) had HHV-8 antibodies. The ages of these 15 patients ranged from 43 to 89 years (mean, 62 yr). Six of 207 (3.0%) blood donors had HHV-8 antibodies. Thus, the prevalence of HHV-8 antibodies in hemodialysis patients in Hualien is higher than that in normal blood donors. The transmission route should be surveyed in detail.     

腹腔CT影像学检查在腹膜透析相关非感染性腹腔并发症中的诊断价值

目的：初步探讨腹腔CT影像学检查在诊断持续性非卧床腹膜透析（continuous ambulatory peritoneal dialysis，CAPD）患者非感染性腹腔并发症中的应用价值。 方法：前瞻性地对2005年至2007年间在我院进行CAPD治疗且临床高度怀疑为透析相关非感染性腹腔并发症的患者进行腹腔CT影像学检查。结合临床资料，综合分析患者是否存在腹腔渗漏、疝气、局部腹透液的聚集和大网膜包裹等情况，评估腹腔CT影像学检查的应用价值。 结果：腹腔CT造影检查发现，11例CAPD患者中有9例出现异常情况，其中包括腹股沟疝气3例，睾丸鞘膜积液1倒，脐疝1例，导管出口处渗漏2例，大网膜包裹2例；其中8例（腹股沟疝气2例，睾丸鞘膜积液1例，脐疝1例，导管出口处渗漏2例，大网膜包裹2例）有手术条件的患者经过手术均得到证实。 结论：在一些存在可疑腹膜透析相关非感染性腹腔并发症的CAPD患者中，腹腔CT影像学检查可能是一种无刨、可靠且灵敏度较高的检查技术，操作简便易行，有助于明确诊断，值得进一步研究。     

Effects of lead and noise exposures on hearing ability

Lead and noise, via different mechanisms, may damage hearing ability, and, in some cases, cause severe and irreversible damage. To explore possible independent and synergistic effects of lead and noise on auditory function, the authors conducted a cross-sectional study in two lead-battery manufacturing factories. Lead and noise were the two most common sources of occupational exposures in the factories. Blood lead level, ambient lead concentration, noise exposure level, and hearing thresholds of 339 lead-battery workers-including clerical and managerial staffs-were measured. The authors obtained demographics and working histories via an interview-based structured questionnaire. A total of 220 lead-battery workers were exposed to high levels of lead and noise; their average blood lead concentration was 56.9 microg/dl, and their average noise exposure level was 86.0 dBALeq. Multivariate analysis, in which possible risk factors of hearing ability were considered, demonstrated a significant correlation between a high, long-term lead exposure index (defined by duration of employment and ambient lead concentration) and decreased hearing ability. In contrast, such a correlation between short-term lead exposure (defined by blood lead level) and hearing ability was not significant. Furthermore, neither noise exposure level alone nor the interaction between noise exposure level and short- or long-term lead exposure was correlated significantly with hearing ability. The present study raises an important, but typically ignored, issue: lead exposure might precipitate a more severe auditory than noise-exposure effect. The preservation of workers' hearing ability requires that preventive measures be taken against noise exposure, which is as essential as measures taken against lead exposure.     

Dopamine precursors and brain function in phenylalanine hydroxylase deficiency

Phenylalanine and tyrosine constitute the two initial steps in the biosynthesis of dopamine, which, in its turn, is the metabolic precursor of noradrenaline and adrenaline. The extracellular phenylalanine concentration influences brain function in phenylalanine deficiency (PHD) by decreased dopamine synthesis. It has been shown to induce EEG slowing, and prolonged the performance time on neuropsychological tests. The tyrosine concentration in the CNS is reduced in PHD, possibly implying insufficient substrate (= tyrosine) for catecholamine synthesis due to competition inhibition, for instance across the blood brain barrier. In experimental studies it has been shown that the synthesis and release of dopamine can be influenced by an increase in the availability of tyrosine. In PHD an extra dietary intake of three doses of tyrosine (160mg/kg/24h) induced a shortsning of reaction time and decreased variability, and in a double-blind crossover study a similar dose has been reported to induce an improvement on psychological tests. In a study with lower doses of tyrosine (110mg/kg/24h) no effect was found on reaction time tests. These findings need to be substantiated, and more detailed information should be obtained.     

Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography of Carotid Artery after Stenting

PURPOSE: This study presents 3-dimensional, contrast-enhanced, magnetic resonance (MR) angiographic appearances of the carotid artery after stenting. METHODS: The authors reviewed contrast-enhanced MR angiograms of 18 carotid arteries in 13 patients. These arteries were not stenotic or occluded in the stented segment, as shown on carotid angio-grams (11 patients) or carotid Doppler images (2 patients) obtained later. RESULTS: Five patients had 1 stent in each of their bilateral carotid arteries. One patient with 1 stent in 1 artery underwent the examination twice with different MR coils. Different artifact patterns were found in 19 carotid-stent examinations. Type 1a involved short segments of false narrowing or false focal occlusion at both ends of the stent (n = 12); the carotid artery in the stented segment between the ends was normal. Types 2a and 2b occurred along the stented segment of the artery between the 2 ends of the stent. Type 2a was milder, with segmental faint signal intensity or luminal stenosis in the entire length of the stented segment (n = 5). Type 2b was total loss of luminal signal intensity over the whole length of the stented segment (n = 2). Last, type 1b was a band of hyperintensity at the ends of type 2a or 2b artifacts. Types 1a and 1b were due to susceptibility effect, and types 2a and 2b were from radio-frequency shielding effect. Both of these effects were identified in MR angiogram of nitinol stents and stainless steel stents. CONCLUSION: Awareness of these artifacts is essential to prevent misdiagnosis.     

Labedipinedilol-C: a third-generation dihydropyridine-type calcium channel antagonist displaying K+ channel opening, NO-dependent and adrenergic antagonist activities

Intravenous and oral labedipinedilol-C showed a dose-dependent long-lasting hypotension and a decrease of heart rate in normotensive and conscious spontaneously hypertensive rats (SHR). In isolated Wistar rat and guinea pig tissues, labedipinedilol-C competitively antagonized (-)isoproterenol-induced cardiac stimulation, tracheal relaxation, and phenylephrine-, CaCl2-, and high-K-induced aorta contractions in a concentration-dependent manner. The estimated pA2 and pKCa values were 8.22+/-0.04 and 7.11+/-0.52, respectively. [H]CGP-12177 binding to ventricle and lung tissues as well as [H]prazosin and [H]nitrendipine binding to brain membranes were inhibited by labedipinedilol-C with Ki values of 2.86, 9.03, 0.39, and 0.05 muM, respectively. The vasorelaxant effects of labedipinedilol-C on phenylephrine (10 microM)-induced contractions were attenuated by removing endothelium, by pretreatment with soluble guanylyl cyclase (sGC) inhibitors ODQ (10 microM) and methylene blue (10 microM), a NOS inhibitor L-NAME (100 microM), a K channel blocker TEA (10 mM), a KATP channel blocker glibenclamide (1 microM), and Ca-dependent K channel blockers apamin (1 microM) and charybdotoxin (0.1 microM). In human umbilical vein endothelial cells (HUVECs), labedipinedilol-C increased NO release, which was significantly inhibited by L-NAME. The Western blot analysis on HUVECs indicated that labedipinedilol-C increased the expression of eNOS. These results indicate that hypotension effects of labedipinedilol-C result from alpha-adrenoceptor and Ca entry-blocking activities and release of NO or NO-related substance from vascular endothelium. The endothelium-independent relaxation of vascular smooth muscle is probably linked to K channel opening and alpha-adrenoceptor-blocking activities.