Prognostic value of clinical and immunological markers in acute phase of SFTS virus infection

SFTS virus (SFTSV) is a novel bunyavirus that causes severe fever with thrombocytopenia syndrome (SFTS), an emerging infectious disease that occurred in China in recent years, with an average case fatality rate of 10-12%. Intervention in the early clinical stage is the most effective measure to reduce the mortality rate of disease. To elucidate the natural course of and immune mechanisms associated with the pathogenesis of SFTSV, 59 laboratory-confirmed SFTS patients in the acute phase, who were hospitalized between October 2010 and September 2011, were enrolled in this study, and the patients sera were dynamically collected and tested for SFTSV viral RNA load, 34 cytokines or chemokines and other related laboratory parameters. All clinical diagnostic factors in the acute phase of SFTS were evaluated and assessed. The study showed that the severity of the disease in 11 (18.6%) patients was associated with abdominal pain (p 0.007; OR = 21.95; 95% CI, 2.32-208.11) and gingival bleeding (p 0.001; OR=122.11; 95% CI, 6.41-2328). The IP-10, TNF-α, IL-6, IL-10, granzyme B and HSP70 levels were higher over the 7-8 days in severe cases, accompanied by altered AST, CK and LDH levels. HSP70 (p 0.012; OR=8.29; 95% CI, 1.58-43.40) was independently correlated with the severity of the early acute phase of SFTSV infection. The severity of SFTS can be predicted based on the presence of symptoms such as abdominal pain and gingival bleeding and on the level of HSP70 in the acute phase of the disease.

Interception of the endotoxin-induced arterial hyporeactivity to vasoconstrictors

Septic shock is a severe pathophysiologic condition characterized by vasodilation, hypotension, hypoperfusion, tissue hypoxia, multiple organ failure and death. It is unclear what causes the septic vasodilation that may result from general dysfunction of vascular smooth muscles (VSMs) or selective disruption of vasomotor balances in VSMs. The latter could be due to enhanced vasorelaxation and/or depressed vasoconstriction. Understanding these may lead to pharmacological interventions to septic vasodilation. Therefore, we performed studies in isolated and perfused mesenteric arterial rings. A 20-h exposure of the rings to lipopolysaccharide (LPS, 1 μg/ml) led to hyporeactivity to phenylephrine (PE). However, the responses of the LPS-treated rings to high concentrations of KCl (60 mM) and ATP remained comparable to control rings, suggesting that contractility of VSMs is retained. The hyporeactivity was marginally affected by atropine, indomethacin and L-NAME, suggesting that endothelium-dependent vasorelaxation does not play a major role. In addition to PE, the LPS-treated rings were hyporeactive to dopamine, histamine and angiotensin II. They showed intermediate hyporeactivity to the thromboxane-A2 receptor agonist U46619. Little hyporeactivity to endothelin-1 (ET-1), serotonin (5-HT) and vasopressin was found. ET-1-induced vasoconstriction occurred without endothelium, whereas the effect of 5-HT was endothelium dependent. Although rings were hyporeactive to some of the vasopressors, their vasoconstriction effects were significantly potentiated by PE co-application. Taken together, these data suggest that the endotoxin-induced vasodilation may not result from general dysfunction of VSMs, neither from the endothelium-dependent vasorelaxation. The promising vascular response to various vasoconstrictors found in this study warrants further investigations of therapeutic potentials of these agents.

[Comparative study on kidney tonifying and yang supporting effects of different processed products of Morinda officinalis]

To compare the pharmacological effects for tonifying kidney and supporting Yang of different processed products of Morinda officinalis. The oral administration of adenine was performed to establish the kidney-Yang deficiency mice model. Four different processed products, namely M. officinalis, morinda pulp, salt-steamed M. officinalis and licorice-processed M. officinalis, were administered, with Guifu Dihuang pills as the control drug, and mice signs, weight, testicular coefficient, seminal vesicle coefficient, serum testosterone, serum cortisol and serum creatinine as evaluation indexes. The results showed that all of the four processed products of M. officinalis could improve the symptoms of the kidney-Yang deficient mice. Among them, salt-steamed M. officinalis had the most significant effect, which was followed by licorice-processed M. officinalis, morinda pulp and M. officinalis.

Pre- and postsynaptic modulations of hypoglossal motoneurons by α-adrenoceptor activation in wild-type and Mecp2(-/Y) mice

Hypoglossal motoneurons (HNs) control tongue movement and play a role in maintenance of upper airway patency. Defects in these neurons may contribute to the development of sleep apnea and other cranial motor disorders including Rett syndrome (RTT). HNs are modulated by norepinephrine (NE) through α-adrenoceptors. Although postsynaptic mechanisms are known to play a role in this effect, how NE modulates the synaptic transmissions of HNs remains poorly understood. More importantly, the NE system is defective in RTT, while how the defect affects HNs is unknown. Believing that information of NE modulation of HNs may help the understanding of RTT and the design of new therapeutical interventions to motor defects in the disease, we performed these studies in which glycinergic inhibitory postsynaptic currents and intrinsic membrane properties were examined in wild-type and Mecp2(-/Y) mice, a mouse of model of RTT. We found that activation of α1-adrenoceptor facilitated glycinergic synaptic transmission and excited HNs. These effects were mediated by both pre- and postsynaptic mechanisms. The latter effect involved an inhibition of barium-sensitive G protein-dependent K(+) currents. The pre- and postsynaptic modulations of the HNs by α1-adrenoceptors were not only retained in Mecp2-null mice but also markedly enhanced, which appears to be a compensatory mechanism for the deficiencies in NE and GABAergic synaptic transmission. The existence of the endogenous compensatory mechanism is an encouraging finding, as it may allow therapeutical modalities to alleviate motoneuronal defects in RTT.

Differential sensitivities of the vascular K(ATP) channel to various PPAR activators

Several agonists of the peroxisome proliferator-activated receptors (PPARs) are currently used for the treatment of metabolic disorders including diabetes. We have recently shown that one of them, Rosiglitazone, inhibits the vascular ATP-sensitive K⁺ (K(ATP)) channel and compromises the coronary vasodilation by the β-adrenoceptor agonist. Here, we show evidence for the channel inhibition by various PPAR agonists, information that may be useful for finding new therapeutical agents with less cardiovascular side-effects and more selective K(ATP) channel blockers targeting at the K(ir)6.1 subunit. Structural comparison of these PPAR agonists may shed insight into the critical chemical groups for the channel inhibition. K(ir)6.1/SUR2B channel was expressed in HEK293 cells and studied in whole-cell voltage clamp. The K(ir)6.1/SUR2B channel was strongly inhibited by several PPAR(γ) agonists with potencies similar to, or higher than, that of Rosiglitazone, while other PPAR(γ) agonists barely inhibited the channel. The K(ir)6.1/SUR2B channel was also inhibited by PPAR(α) and PPAR(β/δ) agonists with intermediate potencies. The structure necessary for the channel inhibition appears to include the thiazole linked to an aromatic or furan ring. Additions of side groups such as small aliphatic chain increased the potency for channel inhibition, while additions of aromatic rings reduced it. These results indicate that the PPAR(γ) agonists with weak K(ATP) channel inhibition may be potential candidates as therapeutical agents, and those with strong channel inhibition may be used as selective K(ATP) channel blockers. The structural information of the PPAR agonists may be useful for the development of new therapeutical modalities with less cardiovascular side-effects.

GABAergic synaptic inputs of locus coeruleus neurons in wild-type and Mecp2-null mice

Rett syndrome is an autism spectrum disorder resulting from defects in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Deficiency of the Mecp2 gene causes abnormalities in several systems in the brain, especially the norepinephrinergic and GABAergic systems. The norepinephrinergic neurons in the locus coeruleus (LC) modulate a variety of neurons and play an important role in multiple functions in the central nervous system. In Mecp2(-/Y) mice, defects in the intrinsic membrane properties of LC neurons have been identified, while how their synaptic inputs are affected remains unclear. Therefore, we performed these brain slice studies to demonstrate how LC neurons are regulated by GABAergic inputs and how such synaptic inputs are affected by Mecp2 knockout. In whole cell current clamp, the firing activity of LC neurons was strongly inhibited by the GABAA receptor agonist muscimol, accompanied by hyperpolarization and a decrease in input resistance. Such a postsynaptic inhibition was significantly reduced (by ~30%) in Mecp2(-/Y) mice. Post- and presynaptic GABABergic inputs were found in LC neurons, which were likely mediated by the G protein-coupled, Ba(2+)-sensitive K(+) channels. The postsynaptic GABABergic inhibition was deficient by ~50% in Mecp2 knockout mice. Although the presynaptic GABABergic modulation appeared normal, both frequency and amplitude of the GABAAergic mIPSCs were drastically decreased (by 30-40%) in Mecp2-null mice. These results suggest that the Mecp2 disruption causes defects in both post- and presynaptic GABAergic systems in LC neurons, impairing GABAAergic and GABABergic postsynaptic inhibition and decreasing the GABA release from presynaptic terminals.

Rosiglitazone selectively inhibits K(ATP) channels by acting on the K(IR) 6 subunit

BACKGROUND AND PURPOSE

Rosiglitazone is an anti-diabetic drug acting as an insulin sensitizer. We recently found that rosiglitazone also inhibits the vascular isoform of ATP-sensitive K(+) channels and compromises vasodilatory effects of β-adrenoceptor activation and pinacidil. As its potency for the channel inhibition is in the micromolar range, rosiglitazone may be used as an effective K(ATP) channel inhibitor for research and therapeutic purposes. Therefore, we performed experiments to determine whether other isoforms of K(ATP) channels are also sensitive to rosiglitazone and what their sensitivities are.

EXPERIMENTAL APPROACH

K(IR) 6.1/SUR2B, K(IR) 6.2/SUR1, K(IR) 6.2/SUR2A, K(IR) 6.2/SUR2B and K(IR) 6.2ΔC36 channels were expressed in HEK293 cells and were studied using patch-clamp techniques.

KEY RESULTS

Rosiglitazone inhibited all isoforms of K(ATP) channels in excised patches and in the whole-cell configuration. Its IC(50) was 10 µmol·L(-1) for the K(IR) 6.1/SUR2B channel and ∼45 µmol·L(-1) for K(IR) 6.2/SURx channels. Rosiglitazone also inhibited K(IR) 6.2ΔC36 channels in the absence of the sulphonylurea receptor (SUR) subunit, with potency (IC(50) = 45 µmol·L(-1) ) almost identical to that for K(IR) 6.2/SURx channels. Single-channel kinetic analysis showed that the channel inhibition was mediated by augmentation of the long-lasting closures without affecting the channel open state and unitary conductance. In contrast, rosiglitazone had no effect on K(IR) 1.1, K(IR) 2.1 and K(IR) 4.1 channels, suggesting that the channel inhibitory effect is selective for K(IR) 6.x channels.

CONCLUSIONS AND IMPLICATIONS

These results suggest a novel K(ATP) channel inhibitor that acts on the pore-forming K(IR) 6.x subunit, affecting the channel gating.

Prolonged exposure to methylglyoxal causes disruption of vascular KATP channel by mRNA instability

Diabetes mellitus is characterized by hyperglycemia and excessive production of intermediary metabolites including methylglyoxal (MGO), a reactive carbonyl species that can lead to cell injuries. Interacting with proteins, lipids, and DNA, excessive MGO can cause dysfunction of various tissues, especially the vascular walls where diabetic complications often take place. However, the potential vascular targets of excessive MGO remain to be fully understood. Here we show that the vascular Kir6.1/SUR2B isoform of ATP-sensitive K(+) (K(ATP)) channels is likely to be disrupted with an exposure to submillimolar MGO. Up to 90% of the Kir6.1/SUR2B currents were suppressed by 1 mM MGO with a time constant of ∼2 h. Consistently, MGO treatment caused a vast reduction of both Kir6.1 and SUR2B mRNAs endogenously expressed in the A10 vascular smooth muscle cells. In the presence of the transcriptional inhibitor actinomycin-D, MGO remained to lower the Kir6.1 and SUR2B mRNAs to the same degree as MGO alone, suggesting that the MGO effect is likely to compromise the mRNA stability. Luciferase reporter assays indicated that the 3'-untranslated regions (UTRs) of the Kir6.1 but not SUR2 mRNA were targeted by MGO. In contrast, the SUR2B mRNAs obtained with in vitro transcription were disrupted by MGO directly, while the Kir6.1 transcripts were unaffected. Consistent with these results, the constriction of mesenteric arterial rings was markedly augmented with an exposure to 1 mM MGO for 2 h, and such an MGO effect was totally eliminated in the presence of glibenclamide. These results therefore suggest that acting on the 3'-UTR of Kir6.1 and the coding region of SUR2B, MGO causes instability of Kir6.1 and SUR2B mRNAs, disruption of vascular K(ATP) channels, and impairment of arterial function.

Rosiglitazone inhibits vascular KATP channels and coronary vasodilation produced by isoprenaline

BACKGROUND AND PURPOSE

Rosiglitazone is an anti-diabetic drug improving insulin sensitivity and glucose uptake in skeletal muscle and adipose tissues. However, several recent clinical trials suggest that rosiglitazone can increase the risk of cardiovascular ischaemia, although other studies failed to show such risks. Therefore, the effects of rosiglitazone on the coronary circulation and any potential vascular targets need to be elucidated. Here, we show that the vascular isoform of the ATP-sensitive K(+) (K(ATP) ) channel is inhibited by rosiglitazone, impairing physiological regulation of the coronary circulation.

EXPERIMENTAL APPROACH

The K(IR) 6.1/SUR2B channel was expressed in HEK293 cells and studied in whole-cell and inside-out patch configurations. The Langendorff heart preparation was used to evaluate rosiglitazone in the coronary circulation of wild-type (WT) and K(IR) 6.1-null (Kcnj8(-/-) ) mice.

KEY RESULTS

K(IR) 6.1/SUR2B channels in HEK cells were inhibited by rosiglitazone in a membrane-delimited manner. This effect was markedly enhanced by sub-micromolar concentrations of glibenclamide and the IC(50) for rosiglitazone fell to 2µM, a therapeutically achievable concentration. In the Langendorff heart preparation rosiglitazone inhibited, concentration-dependently, the coronary vasodilation induced by isoprenaline, without affecting basal coronary tone. Effects of rosiglitazone on coronary perfusion were attenuated by more than 50% in the Kcnj8(-/-) mice, supporting the involvement of K(ATP) channels in this effect of rosiglitazone on the coronary circulation.

CONCLUSIONS AND IMPLICATIONS

These results indicate that the vascular K(ATP) channel is one of the targets of rosiglitazone action, through which this drug may compromise coronary responses to circulating vasodilators and perhaps also to metabolic stress.

SecA alone can promote protein translocation and ion channel activity: SecYEG increases efficiency and signal peptide specificity

SecA is an essential component of the Sec-dependent protein translocation pathway across cytoplasmic membranes in bacteria. Escherichia coli SecA binds to cytoplasmic membranes at SecYEG high affinity sites and at phospholipid low affinity sites. It has been widely viewed that SecYEG functions as the essential protein-conducting channel through which precursors cross the membranes in bacterial Sec-dependent pathways, and that SecA functions as a motor to hydrolyze ATP in translocating precursors through SecYEG channels. We have now found that SecA alone can promote precursor translocation into phospholiposomes. Moreover, SecA-liposomes elicit ionic currents in Xenopus oocytes. Patch-clamp recordings further show that SecA alone promotes signal peptide- or precursor-dependent single channel activity. These activities were observed with the functional SecA at about 1-2 μM. The results show that SecA alone is sufficient to promote protein translocation into liposomes and to elicit ionic channel activity at the phospholipids low affinity binding sites, thus indicating that SecA is able to form the protein-conducting channels. Even so, such SecA-liposomes are less efficient than those with a full complement of Sec proteins, and lose the signal-peptide proofreading function, resembling the effects of PrlA mutations. Addition of purified SecYEG restores the signal peptide specificity and increases protein translocation and ion channel activities. These data show that SecA can promote protein translocation and ion channel activities both when it is bound to lipids at low affinity sites and when it is bound to SecYEG with high affinity. The latter of the two interactions confers high efficiency and specificity.

The disruption of central CO2 chemosensitivity in a mouse model of Rett syndrome

People with Rett syndrome (RTT) have breathing instability in addition to other neuropathological manifestations. The breathing disturbances contribute to the high incidence of unexplained death and abnormal brain development. However, the cellular mechanisms underlying the breathing abnormalities remain unclear. To test the hypothesis that the central CO(2) chemoreception in these people is disrupted, we studied the CO(2) chemosensitivity in a mouse model of RTT. The Mecp2-null mice showed a selective loss of their respiratory response to 1-3% CO(2) (mild hypercapnia), whereas they displayed more regular breathing in response to 6-9% CO(2) (severe hypercapnia). The defect was alleviated with the NE uptake blocker desipramine (10 mg·kg(-1)·day(-1) ip, for 5-7 days). Consistent with the in vivo observations, in vitro studies in brain slices indicated that CO(2) chemosensitivity of locus coeruleus (LC) neurons was impaired in Mecp2-null mice. Two major neuronal pH-sensitive Kir currents that resembled homomeric Kir4.1 and heteromeric Ki4.1/Kir5.1 channels were identified in the LC neurons. The screening of Kir channels with real-time PCR indicated the overexpression of Kir4.1 in the LC region of Mecp2-null mice. In a heterologous expression system, an overexpression of Kir4.1 resulted in a reduction in the pH sensitivity of the heteromeric Kir4.1-Kir5.1 channels. Given that Kir4.1 and Kir5.1 subunits are also expressed in brain stem respiration-related areas, the Kir4.1 overexpression may not allow CO(2) to be detected until hypercapnia becomes severe, leading to periodical hyper- and hypoventilation in Mecp2-null mice and, perhaps, in people with RTT as well.

Involvement of TRP channels in the CO₂ chemosensitivity of locus coeruleus neurons

Catecholaminergic neurons in the locus coeruleus (LC) play a role in the ventilatory response to hypercapnia. Here, we show evidence for the involvement of transient receptor potential (TRP) channels. We found that the input resistance was reduced during an exposure to 8% CO(2) in ~35% LC neurons in mouse brain slices, accompanied by depolarization and higher firing activity. The neuronal responses suggest the opening of Na(+) or nonselective cationic channels instead of the closure of K(+) channels. As a major group of cationic channels, the TRP channels are expressed in the brain, some of which are activated by acidic pH. We therefore screened all representative TRP channels using the quantitative real-time PCR analysis. High levels of mRNA expression of TRPC5, TRPM2, and TRPM7 were found in the LC tissue. Of them, the TRPC5 transcript was the most abundant. The TRPC5 channel was activated by extracellular acidification when expressed in human embryonic kidney (HEK) cells. The TRPC5 currents started to be activated at pH 7.4 with pKa 6.9. The TRPC5 currents were also activated by isohydric hypercapnic and intracellular acidosis in a Ca(2+)-dependent manner. Consistently, the LC neurons were stimulated by both extra- and intracellular acidosis. The stimulatory effect of hypercapnia on LC neurons was eliminated by selective TRPC inhibitor SKF-96365 with and without the blockade of synaptic transmission. Single-cell PCR analysis indicated that TRPC5 mRNAs existed in the LC neurons. Thus these results strongly suggest that the TRP channels are likely to play a role in the CO(2) chemosensitivity of LC neurons, especially TRPC5.

Molecular basis and structural insight of vascular K(ATP) channel gating by S-glutathionylation

The vascular ATP-sensitive K(+) (K(ATP)) channel is targeted by a variety of vasoactive substances, playing an important role in vascular tone regulation. Our recent studies indicate that the vascular K(ATP) channel is inhibited in oxidative stress via S-glutathionylation. Here we show evidence for the molecular basis of the S-glutathionylation and its structural impact on channel gating. By comparing the oxidant responses of the Kir6.1/SUR2B channel with the Kir6.2/SUR2B channel, we found that the Kir6.1 subunit was responsible for oxidant sensitivity. Oxidant screening of Kir6.1-Kir6.2 chimeras demonstrated that the N terminus and transmembrane domains of Kir6.1 were crucial. Systematic mutational analysis revealed three cysteine residues in these domains: Cys(43), Cys(120), and Cys(176). Among them, Cys(176) was prominent, contributing to >80% of the oxidant sensitivity. The Kir6.1-C176A/SUR2B mutant channel, however, remained sensitive to both channel opener and inhibitor, which indicated that Cys(176) is not a general gating site in Kir6.1, in contrast to its counterpart (Cys(166)) in Kir6.2. A protein pull-down assay with biotinylated glutathione ethyl ester showed that mutation of Cys(176) impaired oxidant-induced incorporation of glutathione (GSH) into the Kir6.1 subunit. In contrast to Cys(176), Cys(43) had only a modest contribution to S-glutathionylation, and Cys(120) was modulated by extracellular oxidants but not intracellular GSSG. Simulation modeling of Kir6.1 S-glutathionylation suggested that after incorporation to residue 176, the GSH moiety occupied a space between the slide helix and two transmembrane helices. This prevented the inner transmembrane helix from undergoing conformational changes necessary for channel gating, retaining the channel in its closed state.

Oxidative stress inhibits vascular K(ATP) channels by S-glutathionylation

The K(ATP) channel is an important player in vascular tone regulation. Its opening and closure lead to vasodilation and vasoconstriction, respectively. Such functions may be disrupted in oxidative stress seen in a variety of cardiovascular diseases, while the underlying mechanism remains unclear. Here, we demonstrated that S-glutathionylation was a modulation mechanism underlying oxidant-mediated vascular K(ATP) channel regulation. An exposure of isolated mesenteric rings to hydrogen peroxide (H(2)O(2)) impaired the K(ATP) channel-mediated vascular dilation. In whole-cell recordings and inside-out patches, H(2)O(2) or diamide caused a strong inhibition of the vascular K(ATP) channel (Kir6.1/SUR2B) in the presence, but not in the absence, of glutathione (GSH). Similar channel inhibition was seen with oxidized glutathione (GSSG) and thiol-modulating reagents. The oxidant-mediated channel inhibition was reversed by the reducing agent dithiothreitol (DTT) and the specific deglutathionylation reagent glutaredoxin-1 (Grx1). Consistent with S-glutathionylation, streptavidin pull-down assays with biotinylated glutathione ethyl ester (BioGEE) showed incorporation of GSH to the Kir6.1 subunit in the presence of H(2)O(2). These results suggest that S-glutathionylation is an important mechanism for the vascular K(ATP) channel modulation in oxidative stress.

Lipopolysaccharides up-regulate Kir6.1/SUR2B channel expression and enhance vascular KATP channel activity via NF-kappaB-dependent signaling

Sepsis is a severe medical condition causing a large number of deaths worldwide. Recent studies indicate that the septic susceptibility is attributable to the vascular ATP-sensitive K(+) (K(ATP)) channel. However, the mechanisms underlying the channel modulation in sepsis are still unclear. Here we show evidence for the modulation of vascular K(ATP) channel by septic pathogen lipopolysaccharides (LPS). In isolated mesenteric arterial rings, phenylephrine (PE) produced concentration-dependent vasoconstriction that was relaxed by pinacidil, a selective K(ATP) channel opener. The PE response was disrupted with a LPS treatment. In acutely dissociated aortic smooth myocytes the LPS treatment augmented K(ATP) channel activity, and hyperpolarized the cells. Quantitative PCR analysis showed that LPS raised Kir6.1 and SUR2B transcripts in a concentration-dependent manner, which was suppressed by transcriptional inhibition. Consistently, the same LPS treatment did not affect Kir6.1/SUR2B channels in a heterologous expression system. The LPS effect on Kir6.1 and SUR2B expression was abolished in the presence of NF-kappaB inhibitors. Several other Toll-like receptor ligands also stimulated Kir6.1 and SUR2B expression to a similar degree as LPS. Thus, the effect of LPS on vasodilation involves up-regulation of K(ATP) channel expression, in which the NF-kappaB-dependent signaling plays an important role.

Intrinsic membrane properties of locus coeruleus neurons in Mecp2-null mice

Rett syndrome caused by mutations in methyl-CpG-binding protein 2 (Mecp2) gene shows abnormalities in autonomic functions in which brain stem norepinephrinergic systems play an important role. Here we present systematic comparisons of intrinsic membrane properties of locus coeruleus (LC) neurons between Mecp2(-/Y) and wild-type (WT) mice. Whole cell current clamp was performed in brain slices of 3- to 4-wk-old mice. Mecp2(-/Y) neurons showed stronger inward rectification and had shorter time constant than WT cells. The former was likely due to overexpression of inward rectifier K(+) (K(ir))4.1 channel, and the latter was attributable to the smaller cell surface area. The action potential duration was prolonged in Mecp2(-/Y) cells with an extended rise time. This was associated with a significant reduction in the voltage-activated Na(+) current density. After action potentials, >60% Mecp2(-/Y) neurons displayed fast and medium afterhyperpolarizations (fAHP and mAHP), while nearly 90% WT neurons showed only mAHP. The mAHP amplitude was smaller in Mecp2(-/Y) neurons. The firing frequency was higher in neurons with mAHP, and the frequency variation was greater in cells with both fAHP and mAHP in Mecp2(-/Y) mice. Small but significant differences in spike frequency adaptation and delayed excitation were found in Mecp2(-/Y) neurons. These results indicate that there are several electrophysiological abnormalities in LC neurons of Mecp2(-/Y) mice, which may contribute to the dysfunction of the norepinephrine system in Rett syndrome.

Treatment experience of subsequent complications after Roux-en-Y biliojejunostomy

PURPOSE

Roux-en-Y biliojejunostomy has been frequently used in the management of benign biliary disease. The aim of this study was to summarize one institute's experiences in prevention and management of subsequent complications of Roux-en-Y biliojejunostomy.

METHODS

A retrospective analysis was carried out for patients who underwent reoperation after Roux-en-Y biliojejunostomy from February 1990 through June 2004. Operation history, laboratory test data before the last operation, and images were collected.

RESULTS

Sixty-one patients, aged 36-60 years and with a 3.5-year average operation interval, were involved in the study. Anastomotic stricture (47, 80.3%), recurrent calculi (36, 60.7%), and biliary tract infection (all) were the most common complications after Roux-en-Y biliojejunostomy. Other complications (such as calculi of the intrahepatic duct or intrahepatic duct stricture, malformed or twisted jejunum loop, too long or too short proximal jejunum, disappearance of the normal form of anastomosis, and adhesion of the intestinal loop) were also detected by laparotomy.

CONCLUSION

Calculus, stricture, and infection arise as a result of each other. Lessening of the anastomotic stricture, fluent drainage of the distal jejunum below the anastomosis, and relieving pressure of gastrointestinal tract are pivotal in decreasing subsequent complications after Roux-en-Y biliojejunostomy.