Role of thromboxane A2-activated nonselective cation channels in hypoxic pulmonary vasoconstriction of rat

Hypoxia-induced pulmonary vasoconstriction (HPV) is critical for matching of ventilation/perfusion in lungs. Although hypoxic inhibition of K+ channels has been a leading hypothesis for depolarization of pulmonary arterial smooth muscle cells (PASMCs) under hypoxia, pharmacological inhibition of K+ channels does not induce significant contraction in rat pulmonary arteries. Because a partial contraction by thromboxane A2 (TXA2) is required for induction of HPV, we hypothesize that TXA2 receptor (TP) stimulation might activate depolarizing nonselective cation channels (NSCs). Consistently, we found that 5–10 nM U46619, a stable agonist for TP, was indispensible for contraction of rat pulmonary arteries by 4-aminopyridine, a blocker of voltage-gated K+ channel (Kv). Whole cell voltage clamp with rat PASMC revealed that U46619 induced a NSC current ( INSC,TXA2) with weakly outward rectifying current-voltage relation. INSC,TXA2 was blocked by ruthenium red (RR), an antagonist of the transient receptor potential vanilloid-related channel (TRPV) subfamily. 2-Aminoethoxydiphenyl borate, an agonist for TRPV1–3, consistently activated NSC channels in PASMCs. In contrast, agonists for TRPV1 (capsaicin), TRPV3 (camphor), or TRPV4 (α-PDD) rarely induced an increase in the membrane conductance of PASMCs. RT-PCR analysis showed the expression of transcripts for TRPV2 and -4 in rat PASMCs. Finally, it was confirmed that pretreatment with RR largely inhibited HPV in the presence of U46619. The pretreatment with agonists for TRPV1 (capsaicin) and TRPV4 (α-PDD) was ineffective as pretone agents for HPV. Taken together, it is suggested that the concerted effects of INSC,TXA2 activation and Kv inhibition under hypoxia induce membrane depolarization sufficient for HPV. TRPV2 is carefully suggested as the TXA2-activated NSC in rat PASMC.

Comparison of the Incidence of parenchymal hematoma and poor outcome in patients with carotid terminus occlusion treated with intra-arterial urokinase alone or with combined IV rtPA and intra-arterial urokinase

BACKGROUND AND PURPOSE

Patients with acute CTO generally have a poor prognosis, despite IV or IA thrombolytic treatment. The goal of this study was to analyze the results of patients with CTO who had IA urokinase treatment with or without initial IV rtPA based on a bridging protocol.

MATERIALS AND METHODS

Sixteen consecutive patients with acute ischemic stroke due to CTO who had combined IV and IA or a single IA thrombolytic treatment were enrolled. The baseline characteristics and prognosis were described. The patients who did and did not develop a PH shortly after treatment were compared.

RESULTS

The mean age was 66.4 years, and the median initial NIHSS score was 17. The median dose of IA urokinase was 320,000 U, and recanalization (TICI grade II-III) was achieved in 12 patients (75%). However, 5 patients died and 10 patients had poor prognosis with mRS 5-6 at discharge. Six patients (37.5%) with a PH had a higher NIHSS score 1 day after treatment (26.7 versus 13.6, P = .002), and they had more frequent mortality (66.7% versus 10.0%, P = .018) and worse prognosis (mRS 5-6; 100% versus 40%, P = .016) at discharge than patients without PH.

CONCLUSIONS

Patients with CTO who received IA urokinase treatment based on a bridging protocol had a poor prognosis. The development of PH might affect this outcome.

Akt/mTOR counteract the antitumor activities of cixutumumab, an anti-insulin-like growth factor I receptor monoclonal antibody

Recent reports have shown limited anticancer therapeutic efficacy of insulin-like growth factor receptor (IGF-1R)-targeted monoclonal antibodies (mAb), but the resistance mechanisms have not been completely identified. Because cooperation between epidermal growth factor receptor (EGFR) and IGF-IR could cause resistance to inhibitors of individual receptor tyrosine kinases, we investigated the involvement of EGFR signaling in resistance to IGF-1R mAb and the underlying mechanisms of action. Most head and neck squamous cell carcinoma (HNSCC) tissues had coexpression of total and phosphorylated IGF-1R and EGFR at high levels compared with paired adjacent normal tissues. Treatment with cixutumumab (IMC-A12), a fully humanized IgG1 mAb, induced activation of Akt and mTOR, resulting in de novo synthesis of EGFR, Akt1, and survivin proteins and activation of the EGFR pathway in cixutumumab-resistant HNSCC and non-small cell lung cancer (NSCLC) cells. Targeting mTOR and EGFR pathways by treatment with rapamycin and cetuximab (an anti-EGFR mAb), respectively, prevented cixutumumab-induced expression of EGFR, Akt, and survivin and induced synergistic antitumor effects in vitro and in vivo. These data show that resistance to IGF-1R inhibition by mAbs is associated with Akt/mTOR-directed enhanced synthesis of EGFR, Akt1, and survivin. Our findings suggest that Akt/mTOR might be effective targets to overcome the resistance to IGF-1R mAbs in HNSCC and NSCLC.

Incidence of hypertension in Korea: 5-year follow-up study

Limited data are available about the incidence of hypertension over the 5-yr in non-hypertensive subjects. The study subjects were 1,806 subjects enrolled in a rural area of Daegu, Korea for a cohort study from August to November 2003. Of them, 1,287 (71.3%) individuals had another examination 5 yr later. To estimate the incidence of hypertension, 730 non-hypertensive individuals (265 males; mean age = 56.6 ± 11.1 yr-old) at baseline examination were analyzed in this study. Hypertension was defined as either a new diagnosis of hypertension or self-reports of newly initiated antihypertensive treatment; prehypertension was if the systolic blood pressure was 120-139 mmHg and/or diastolic blood pressure was 80-89 mmHg. During the 5-yr follow-up, 195 (26.7%) non-hypertensive individuals developed incident hypertension. The age-adjusted 5-yr incidence rates of hypertension were 22.9% (95% confidence interval [CI] = 19.9-29.0) in overall subjects, 22.2% (95% CI = 17.2-27.2) in men, and 24.3% (95% CI = 20.4-28.2) in women. The incidence rates of hypertension significantly increased with age. In the multivariate analysis, prehypertension (Odds ratio [OR] 2.25; P < 0.001) and older age (OR 2.26; P = 0.010) were independent predictors for incident hypertension. In this rapidly aging society, population-based preventive approach to decrease blood pressure, particularly in subjects with prehypertension, is needed to reduce hypertension.

Enterobius vermicularis eggs discovered in coprolites from a medieval Korean mummy

While the presence of pinworm eggs in archaeological samples has been reported by many researchers in the New World, those have been detected very scarcely in the Old World, especially in East Asian countries. In fact, many parasite species were recovered from the archeological remains in Korea, eggs of Enterobius vermicularis had not been found. Recently, a female mummy buried in the 17th century was discovered in the Joseon tomb from Dangjin-gun, Chungcheongnam-do, Korea. After rehydration process for 12 days, investigations were carried on the luminal surface of the colon. From them, 3 eggs of E. vermicularis were recovered. They were elliptical, transparent with a thin egg shell, 50.3±5.2 µm (length) and 28.2±3.9 µm (width) in size. This is the first discovery of E. vermicularis eggs in East Asia.

Inhibition of Ca2+-release-activated Ca2+ channel (CRAC) and K+ channels by curcumin in Jurkat-T cells

The increase in cytoplasmic Ca(2+) concentration (Δ[Ca(2+)](c)) mediated by the Ca(2+)-release-activated Ca(2+) channel (CRAC) is a critical signal for the activation of lymphocytes. Also, the voltage-gated K(+) channel (K(v)) and intermediate-conductance Ca(2+)-activated K(+) channel (IKCa1/SK4) have drawn attention as pharmacological targets for regulating immune responses. Since polyphenolic agents have various immunomodulatory effects, here we compared the effects of curcumin, rosmarinic acid, resveratrol, and epigallocatechin gallate on the ionic currents through CRAC (I(CRAC)), K(v) (I(Kv)), SK4 (I(SK4)) and on the Δ[Ca(2+)](c) of Jurkat-T cells using the patch clamp technique and fura-2 spectrofluorimetry. Curcumin (10 µM) inhibited store-operated Ca(2+) entry (SOCE). Consistently, dose-dependent inhibition of I(CRAC) by curcumin was confirmed in Jurkat-T (IC(50), 5.9 µM) and the HEK293 cells overexpressing Orai1 and STIM1 (IC(50), 0.6 µM). Also, curcumin inhibited both I(Kv) (IC(50), 11.9 µM) and I(SK4) (IC(50), 4.2 µM). The other polyphenols (rosmarinic acid, resveratrol, and epigallocatechin gallate at 10 - 30 µM) had no effect on SOCE and showed only a partial inhibition of the K(+) currents. In summary, among the tested polyphenolic agents, curcumin showed prominent inhibition of major ion channels in lymphocytes, which might contribute to the anti-inflammatory effects of curcumin. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10209FP].

Sex determination of Joseon people skeletons based on anatomical, cultural and molecular biological clues

Sex determination is very integral to examinations conducted by anatomists on human skeletons discovered in the archaeological field. In Korea, as in other countries, cultural or anatomical information has been the tool of first resort in making such determinations. In cases in which anatomical examination has revealed only borderline characteristics, PCR-based analysis of X/Y-chromosome genes has been employed. Even so, there are as yet very few reports on how accurately the respective results correspond with each other. In this study on 34 examined medieval Korean skeletons, 11 (32.3%) showed perfectly matching results for the three methods of sex determination. In the cases in which the cultural and anatomical findings were discordant, the amelogenin assay corroborated either the former or the latter. Although we must admit the relatively limited role of aDNA analysis, when only very small amounts of amplifiable DNA remain, we believe that the amelogenin assay can be very meaningful to Korean anatomists when employed in adjunct to conventional anatomically or culturally based sex determination.

Risk Factors for Intrahepatic Recurrence after Resection of Hepatocellular Carcinomas in Patients with Hepatitis B Virus Infection

PURPOSE

Although surgical resection offers patients with HCC the chance of a cure, the post-resection tumor recurrence rate is high, with reported cumulative 5-year tumor recurrence rates ranging from 40 to 70%. The objective of this study was to investigate risk factors for intrahepatic recurrence after resection of hepatocellular carcinoma, especially in patients with hepatitis B virus infection.

METHODS

Between January 1999 and December 2003, 59 patients in our Hospital with hepatitis B virus infection underwent liver resection for hepatocellular carcinoma. Clinical, biological, and histopathological characteristics of these patients were collected and tested for their prognostic significance using a Chi-square test and a Student's t-test. Time to recurrence and survival rate were analyzed by the Kaplan-Meier method.

RESULTS

Of the 59 patients who underwent liver resection, 24 (41%) experienced intrahepatic recurrence. The 1-, 3-, and 5-year overall survival rates of total enrolled patients were 83%, 63%, and 42%, respectively. The 1-, 3-, and 5-year overall survival rates after recurrence were 87%, 52%, and 20%, respectively. The risk factors for early recurrence were elevated serum aspartate aminotransferase (AST) level (p=0.044) and larger tumor size (p=0.049). For late recurrence, greater tumor size (p=0.039) was the only risk factor.

CONCLUSION

Tumor size and serum aspartate aminotransferase are risk factors of intrahepatic recurrence after resection of HCC in patients with chronic hepatitis B virus infection. This finding indicates that patients who have these risk factors should be under more careful supervision and have more aggressive follow-up.

Hemodynamic impact of fetal-variant Willisian circle on cerebral circulation: a duplex ultrasonography study

BACKGROUND/AIMS

The Willisian circle can redistribute the vertebrobasilar flow and the reduction of flow is attributable to orthrostatic presyncope. To evaluate this hemodynamic aspect, we investigated anterior and posterior cerebral blood flow (CBF) volume distributions according to the variation of the Willisian circle, and compared those between controls and patients with presyncope.

METHODS

Subjects underwent cerebral CT angiography and color-coded duplex sonography measuring flow volumes of the internal carotid artery (ICAs) and vertebral artery (VAs). According to clinical manifestations and Willisian configurations, CBF volume patterns were analyzed.

RESULTS

Between the presyncope (n = 25) and control groups (n = 76), the prevalence of fetal-variant Willisian configuration (48% vs. 21%, p = 0.004) and posterior CBF volume (126 ± 85 vs. 165 ± 64 ml/min, p = 0.015) was significantly different, but A1 morphology, anterior CBF, and total CBF volumes were not. Total CBF volume was 769 ± 176 ml/min (80% ICAs and 20% VAs). The posterior CBF volume lowered significantly (172 ± 70 vs. 122 ± 62 vs. 92 ± 44 ml/min; p < 0.001) toward the two-sided fetal type variation, although total CBF volume is similar among the three groups (p = 0.742).

CONCLUSIONS

The present study suggests that Willisian configuration contributes to orthostatic presyncope and flow distribution of the cerebral circulation.

Expression of TASK-2 and its upregulation by B cell receptor stimulation in WEHI-231 mouse immature B cells

Stimulation of B cell receptors (BCR ligation) induces apoptosis of immature B cells, which is critical to the elimination of self-reactive clones. In the mouse immature B cell line WEHI-231, the authors previously reported two types of background K+ channels with large (∼300 pS, LKbg) and medium (∼100 pS, MKbg) conductance in divalent cation-free conditions. While the authors have recently identified LKbg as TREK-2, the molecular nature of MKbg is unknown yet. In the present study, the authors found that BCR ligation markedly increased the background K+ conductance of WEHI-231. A single-channel study revealed that MKbg activity is increased by BCR ligation and that the biophysical properties (unitary conductance and pH sensitivity) of MKbg are consistent with those of TWIK-related acid-sensitive K+ channel 2 (TASK-2). The expression of TASK-2 and its upregulation by BCR ligation were confirmed by RT-PCR and immunoblot assays in WEHI-231. The BCR ligation-induced increase of K+ current was prevented by calcineurin inhibitors (cyclosporine A or FK506), and also by TASK-2-specific small interfering RNA (siRNA) transfection (si-TASK-2). Furthermore, si-TASK-2 attenuated the apoptosis of WEHI-231 caused by BCR ligation. TASK-2 activity and its mRNA were also confirmed in the primary splenic B cells of mouse. Summarizing, the authors report for the first time the expression of TASK-2 in B cells and surmise that the upregulation of TASK-2 by BCR ligation is associated with the apoptosis of immature B cells.

Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

OBJECTIVE

Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility.

METHODS

A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8).

RESULTS

The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01).

CONCLUSION

Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent.

Exercise training increases inwardly rectifying K(+) current and augments K(+)-mediated vasodilatation in deep femoral artery of rats

AIMS

A moderate increase in extracellular [K(+)] ([K(+)](e)) induces relaxation of small arteries by activating inwardly rectifying K(+) current (I(Kir)). The K(+)-induced vasodilatation is an important mechanism for exercise-induced hyperaemia in skeletal muscle. We investigated whether I(Kir) and K(+)-induced vasodilatation are enhanced in deep femoral arteries (DFAs) from exercise-trained rats (ET rats; treadmill running for 20 min at 20 m/min, 3 days/week for 2 weeks). The effects of exercise training on K(+)-induced vasodilatation and I(Kir) were also investigated in cerebral (CA) and mesenteric arteries.

METHODS AND RESULTS

The K(+)-induced vasodilatation of DFAs and the density of I(Kir) and voltage-gated K(+) current (I(Kv)) were increased in DFA myocytes of ET rats. The myogenic tone of the DFA was unchanged by exercise. Although similar functional up-regulations of I(Kir) and I(Kv) were observed in CA myocytes, the K(+)-induced vasodilatation was not increased in the CA of ET rats. Interestingly, concomitant to the increases in I(Kir) and I(Kv), background Na(+) conductance was also increased in the CA myocytes. However, such an effect was not observed in DFA myocytes from ET rats. Neither I(Kir) nor K(+)-induced vasodilatation was observed in mesenteric arteries of ET rats.

CONCLUSION

The present study provides evidence that regular exercise up-regulates I(Kir) in DFA and CA myocytes. Although the increase in I(Kir) was observed in two types of arteries, augmentation of K(+)-induced relaxation was observed only in the DFA of ET rats, possibly due to the increased Na(+) conductance in CA myocytes. The increases in I(Kir) and K(+)-induced vasodilatation of the arteries of skeletal muscle suggest novel mechanisms of improved exercise hyperaemia with physical training.

Identification of oxidized serum albumin in the cerebrospinal fluid of ischaemic stroke patients

BACKGROUND AND PURPOSE

  Extensive evidence has shown that oxidative stress mediates neuronal death in animal models of hypoxic-ischaemia. Brain biomarkers of oxidative stress need to be identified in order to better understand and treat brain damage in human stroke patients. The present study was conducted to identify potential target proteins of oxidative stress in the cerebrospinal fluid (CSF) of stroke patients with acute ischaemic brain injury.

METHODS

  We performed two-dimensional polyacrylamide gel electrophoresis to separate protein samples obtained from the CSF of control and stroke patients. To determine protein oxidation levels, oxyblot was then used to detect protein carbonyls that were determined by formation of a stable 2,4-dinitrophenylhydrazine (DNP) product using an anti-DNP antibody.

RESULTS

  We found that oxidation of serum albumin was increased in the CSF from stroke patients as well as rats who underwent permanent middle cerebral artery occlusion (6.5%, 23%, respectively). In stroke patients, oxidized albumin levels correlated to neurologic indications.

CONCLUSIONS

  The present study suggests that oxidized albumin in CSF can be utilized as an oxidative stress marker in human stroke patients.

High-throughput DNA hypermethylation profiling in different ovarian epithelial cancer subtypes using universal bead array

DNA hypermethylation is common and plays a critical role in the regulation of gene expression. It is considered a major cause of carcinogenesis. High-throughput profiling method has been developed to analyze the methylation status of hundreds of pre-selected genes simultaneously. The aim of this study was to analyze promoter hypermethylation profiles of each subtype of ovarian epithelial cancer (OEC), to improve the understanding of the role of epigenetic silencing in carcinogenesis. DNA hypermethylation profiles on fresh frozen tissue samples of 5 serous, 3 mucinous, 5 endometrioid and 4 clear cell types of OEC, as well as 5 normal ovarian tissue samples as control. We used a high-throughput method for analyzing the hypermethylation status of 1,505 CpG loci selected from 871 genes simultaneously by GoldenGate Methylation Cancer Panel I (Illumina Human-6 v2 Expression BeadChip). Methylation status of seven genes was verified by methylation specific PCR (MSP). We identified 20, 37, 15 and 56 hypermethylated CpG locations in serous, mucinous, endometrioid and clear cell type OEC compared to control. Only 6 CpG loci were commonly hypermethylated across all subtypes of OEC. Hypermethylated loci of serous 17 (81.0%) and endometrioid type 10 (71.4%) were identical to that of clear cell type. However, mucinous type showed 17 peculiar loci (43.6%) out of 39 hypermethylated loci. The unique DNA hypermethylation patterns identified in different OEC subtypes suggest that their cause may involve different epigenetic mechanisms and the Bead chip used in this study is a useful tool to analyze DNA hypermethylation.

Tracheobronchial aspergillosis following primary cutaneous aspergillosis in a lung-transplant recipient

Invasive aspergillosis, a major problem during the post-transplant period, typically presents with pneumonia or tracheobronchitis in lung transplant recipients. In contrast, primary cutaneous aspergillosis is very rarely observed in lung-transplant recipients. In this report, we describe a case of tracheobronchial aspergillosis following primary cutaneous aspergillosis in a lung-transplant recipient. Early diagnosis of tracheobronchial aspergillosis is important because occult tracheobronchial aspergillosis can be potentially lethal. Our report suggests that surveillance bronchoscopy may facilitate identification of occult tracheobronchial invasion in lung-transplant recipients with primary cutaneous aspergillosis.

Functional Expression of TRPV4 Cation Channels in Human Mast Cell Line (HMC-1)

Mast cells are activated by specific allergens and also by various nonspecific stimuli, which might induce physical urticaria. This study investigated the functional expression of temperature sensitive transient receptor potential vanilloid (TRPV) subfamily in the human mast cell line (HMC-1) using whole-cell patch clamp techniques. The temperature of perfusate was raised from room temperature (RT, 23~25℃ to a moderately high temperature (MHT, 37~39℃ to activate TRPV3/4, a high temperature (HT, 44~46℃ to activate TRPV1, or a very high temperature (VHT, 53~55℃ to activate TRPV2. The membrane conductance of HMC-1 was increased by MHT and HT in about 50% (21 of 40) of the tested cells, and the I/V curves showed weak outward rectification. VHT-induced current was 10-fold larger than those induced by MHT and HT. The application of the TRPV4 activator 4α-phorbol 12,13-didecanoate (4αPDD, 1µM) induced weakly outward rectifying currents similar to those induced by MHT. However, the TRPV3 agonist camphor or TRPV1 agonist capsaicin had no effect. RT-PCR analysis of HMC-1 demonstrated the expression of TRPV4 as well as potent expression of TRPV2. The [Ca(2+)](c) of HMC-1 cells was also increased by MHT or by 4αPDD. In summary, our present study indicates that HMC-1 cells express Ca(2+)-permeable TRPV4 channels in addition to the previously reported expression of TRPV2 with a higher threshold of activating temperature.