Guey-Mei Jow

Melatonin ameliorates brain injury induced by systemic lipopolysaccharide in neonatal rats

Our previous study showed that lipopolysaccharide (LPS)-induced brain injury in the neonatal rat is associated with nitrosative and oxidative stress. The present study was conducted to examine whether melatonin, an endogenous molecule with antioxidant properties, reduces systemic LPS-induced nitrosative and oxidative damage in the neonatal rat brain. Intraperitoneal (i.p.) injection of LPS (2mg/kg) was administered to Sprague-Dawley rat pups on postnatal day 5 (P5), and i.p. administration of melatonin (20mg/kg) or vehicle was performed 5min after LPS injection. Sensorimotor behavioral tests were performed 24h after LPS exposure, and brain injury was examined after these tests. The results show that systemic LPS exposure resulted in impaired sensorimotor behavioral performance, and acute brain injury, as indicated by the loss of oligodendrocyte immunoreactivity and a decrease in mitochondrial activity in the neonatal rat brain. Melatonin treatment significantly reduced LPS-induced neurobehavioral disturbances and brain damage in neonatal rats. The neuroprotective effect of melatonin was associated with attenuation of LPS-induced nitrosative and oxidative stress, as indicated by the decreased nitrotyrosine- and 4-hydroxynonenal-positive staining in the brain following melatonin and LPS exposure in neonatal rats. Further, melatonin significantly attenuated LPS-induced increases in the number of activated microglia in the neonatal rat brain. The protection provided by melatonin was also associated with a reduced number of inducible nitric oxide synthase (iNOS)+ cells, which were double-labeled with ED1 (microglia). Our results show that melatonin prevents the brain injury and neurobehavioral disturbances induced by systemic LPS exposure in neonatal rats, and its neuroprotective effects are associated with its impact on nitrosative and oxidative stress.

Fine mapping of hepatitis B virus pre-S deletion and its association with hepatocellular carcinoma.

Naturally occurring pre‐S deletion mutants have been identified in hepatitis B virus (HBV)‐related hepatocellular carcinoma (HCC).

Sensitization by Pulmonary Reactive Oxygen Species of Rat Vagal Lung C-Fibers: The Roles of the TRPV1, TRPA1, and P2X Receptors

Sensitization of vagal lung C-fibers (VLCFs) induced by mediators contributes to the pathogenesis of airway hypersensitivity, which is characterized by exaggerated sensory and reflex responses to stimulants. Reactive oxygen species (ROS) are mediators produced during airway inflammation. However, the role of ROS in VLCF-mediated airway hypersensitivity has remained elusive. Here, we report that inhalation of aerosolized 0.05% H2O2 for 90 s potentiated apneic responses to intravenous capsaicin (a TRPV1 receptor agonist), α,β-methylene-ATP (a P2X receptor agonist), and phenylbiguanide (a 5-HT3 receptor agonist) in anesthetized rats. The apneic responses to these three stimulants were abolished by vagatomy or by perivagal capsaicin treatment, a procedure that blocks the neural conduction of VLCFs. The potentiating effect of H2O2 on the apneic responses to these VLCF stimulants was prevented by catalase (an enzyme that degrades H2O2) and by dimethylthiourea (a hydroxyl radical scavenger). The potentiating effect of H2O2 on the apneic responses to capsaicin was attenuated by HC-030031 (a TRPA1 receptor antagonist) and by iso-pyridoxalphosphate-6-azophenyl-2′,5′-disulphonate (a P2X receptor antagonist). The potentiating effect of H2O2 on the apneic responses to α,β-methylene-ATP was reduced by capsazepine (a TRPV1 receptor antagonist), and by HC-030031. The potentiating effect of H2O2 on the apneic responses to phenylbiguanide was totally abolished when all three antagonists were combined. Consistently, our electrophysiological studies revealed that airway delivery of aerosolized 0.05% H2O2 for 90 s potentiated the VLCF responses to intravenous capsaicin, α,β-methylene-ATP, and phenylbiguanide. The potentiating effect of H2O2 on the VLCF responses to phenylbiguanide was totally prevented when all antagonists were combined. Inhalation of 0.05% H2O2 indeed increased the level of ROS in the lungs. These results suggest that 1) increased lung ROS sensitizes VLCFs, which leads to exaggerated reflex responses in rats and 2) the TRPV1, TRPA1, and P2X receptors are all involved in the development of this airway hypersensitivity.

Impact on Neonatal Outcome and Anthropometric Growth in Very Low Birth Weight Infants with Histological Chorioamnionitis

BACKGROUND/PURPOSE Chorioamnionitis (CAM) is one of the main causes of preterm labor. The specific aim of our study was to evaluate neonatal outcome and anthropometric growth at the corrected age of 2 years after exposure to an adverse intrauterine event of CAM in very low birth weight (VLBW, less than 1500 g) infants. METHODS One hundred and nineteen VLBW infants had adequate placental histological data available for the study. Maternal and perinatal characteristics and neonatal morbidity were determined. The infants were followed up prospectively and their anthropometric growth was recorded in the neonatal follow-up clinic for 2 years. RESULTS Histological CAM was evident in 64 cases (53.8%, CAM group). Patients with histological CAM delivered earlier (27.8 +/- 2.9 vs. 29.6 +/- 3.6 weeks, p = 0.003), and they had higher incidence of preterm premature rupture of membranes (PPROM, p less than 0.001) and longer ventilation days (p = 0.001). After adjusting for gestational age, sepsis (aOR, 3.355), bronchopulmonary dysplasia (aOR, 3.018) and mechanical ventilation (aOR, 4.094) had a higher incidence in the CAM group. At the corrected ages of 6, 12, 18 and 24 months, anthropometric measurements, including body weight, body height and head circumference, were similar for the study and control infants. CONCLUSION Histological CAM was associated with a higher incidence of PPROM, sepsis, bronchopulmonary dysplasia, more mechanical ventilation and longer ventilation days. However, at the age of 2 years, CAM had no impact on anthropometric growth.

A longitudinal study of cortisol responses, sleep problems, and psychological well-being as the predictors of changes in depressive symptoms among breast cancer survivors

OBJECTIVE This study examined whether the changes in sleep problems, attachment styles, meaning in life, and salivary cortisol over the course of 14 months were the predictors of changes in depressive symptoms in women with breast cancer at post-treatment stage. METHODS The study included 76 participants who completed active breast cancer treatment with longitudinal data collected at five points, including baseline assessment (T0) and the four follow-ups after baseline: T1 (in the 2nd month), T2 (in the 5th month), T3 (in the 8th month), and T4 (in the 14th month). The self-reported questionnaires included the Medical Outcomes Study Sleep (MOS-Sleep) scale; the Beck Depression Inventory-II (BDI-II); the Experiences in Close Relationships-Revised (ECR-R) scale for measuring anxiety and avoidance dimensions of attachment style; and the Meaning in Life Questionnaire (MLQ), consisting of the MLQ-Presence scale and the MLQ-Search scale. The participants collected their salivary cortisol at home at six time points: upon waking, 30 and 45 min after waking, and at 1200 h, 1700 h, and 2100 h. RESULTS Higher scores on for anxiety-related attachment style and the sleep problems index at baseline were associated with more severe initial depressive symptoms after the age, BMI, cancer, and treatment variables were controlled. The presence of meaning in life at baseline was negatively correlated with initial depressive symptoms. Moreover, the decreases in the presence of meaning in life over the course of 14 months predicted more severe depressive symptoms. In addition, the persistent increases of cortisol level at 2100 h across 14-month follow-ups predicted worsening depressive symptoms. CONCLUSIONS Lacking presence of meaning in life as a predictor for severe depressive symptoms demonstrates that breast cancer survivors who lack psychological well-being are more likely to be depressed. The persistent elevation of cortisol levels at night also indicates breast cancer survivors to be at high risk of depression.

Dehydroeburicoic acid induces calcium- and calpain-dependent necrosis in human U87MG glioblastomas.

Dehydroeburicoic acid (DeEA) is a triterpene purified from medicinal fungi such as Antrodia camphorate, the crude extract of which is known to exert cytotoxic effects against several types of cancer cells. We aim to test the hypothesis that DeEA possesses significant cytotoxic effects against glioblastomas, one of the most frequent and malignant brain tumors in adults. 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase release assays indicated that DeEA inhibited the proliferation of the human glioblastoma cell U87MG. In addition, Annexin V and propidium iodide staining showed that DeEA treatment led to a rapid increase of glioblastomas in the necrotic/late apoptotic fraction, whereas cell cycle analysis revealed that DeEA failed to significantly enhance the population of U87MG cells in the hypodiploid (sub-G1) fraction. Using electron microscopy, we found that DeEA induced significant cell enlargements, massive cytoplasmic vacuolization, and loss of mitochondrial membrane integrity. DeEA treatment triggered an intracellular Ca(2+) increase, and DeEA-induced cell death was significantly attenuated by BAPTA-AM but not ethylenediaminetetraacetic acid or ethylene glycol tetraacetic acid. DeEA instigated a reduction of both mitochondrial transmembrane potential and intracellular ATP level. Moreover, DeEA induced proteolysis of alpha-spectrin by calpain, and DeEA cytotoxicity in U87MG cells was caspase-independent but was effectively blocked by calpain inhibitor. Interestingly, DeEA also caused autophagic response that was prevented by calpain inhibitor. Taken together, these results suggest that in human glioblastomas, DeEA induces necrotic cell death that involves Ca(2+) overload, mitochondrial dysfunction, and calpain activation.

The Long-Term Effects of Psychotherapy Added to Pharmacotherapy on Morning to Evening Diurnal Cortisol Patterns in Outpatients with Major Depression

Background: Psychotherapy added to pharmacotherapy results in greater improvement in clinical outcomes than does pharmacotherapy alone. However, few studies examined how psychotherapy coupled with pharmacotherapy could produce a long-term protective effect by improving the psychobiological stress response. Methods: The researchers recruited 63 subjects with major depressive disorder (MDD) in an outpatient department of psychiatry at a general hospital. The randomly assigned subjects formed 2 groups: 29 in combined therapy (COMB) and 34 in monotherapy (MT). The COMB included 8 weekly body-mind-spirit group psychotherapy sessions added to pharmacotherapy. MT consisted of pharmacotherapy only. The outcome measures, collected at the subjects’ homes, included the Beck Depression Inventory II (BDI-II), the State Trait Anxiety Inventory (STAI) and salivary cortisol on awakening, 45 min after awakening, and at 12.00, 17.00 and 21.00 h. Evaluation of outcome measures was at baseline condition, and at months 2 (end of additional psychotherapy), 5 and 8. Results: While the decreases in symptoms of depression were similar between COMB and MT (p > 0.05), the reductions in anxiety state were greater in COMB than in MT during the 8-month follow-up (p < 0.05). A steeper diurnal cortisol pattern more likely occurred in COMB than in MT in the 3 follow-up periods (p < 0.05, p <0.001 and p < 0.01). Conclusions: The superior outcomes of group psychotherapy added to pharmacotherapy for MDD outpatients could relate to decreasing the anxiety state and to producing long-term impacts on positive stress endocrine outcomes seen as a steeper diurnal cortisol pattern.

Differential localization of rat Eag1 and Eag2 potassium channels in the retina.

Despite of their wide expression in the brain, the precise neurophysiological role of rat Eag1 (rEag1) and Eag2 (rEag2) K(+) channels remains elusive. Our previous studies in hippocampal pyramidal neurons demonstrate a somatodendritic localization of rEag1 and rEag2 channels, suggesting that the two channel isoforms may contribute to setting the membrane excitability of somas and dendrites. Here, we aim to further characterize the cellular and subcellular localization patterns of rEag1 and rEag2 proteins by studying their laminar distribution in the retina. Confocal microscopic analyses of immunofluorescence data revealed that rEag1 and rEag2 K(+) channels exhibit distinct cellular expression pattern in the retina. rEag1 immunoreactivity was most prominent in the outer half of the inner plexiform layer, whereas strong rEag2 immunostain was found in the outer and inner segments of photoreceptor cells, the outer plexiform layer, and the inner nuclear layer. These results suggest that rEag1 and rEag2 K(+) channels may play a significant role in the transmission of electrical signals along the retinal neuronal circuits. We also performed double-labeling experiments to demonstrate that rEag1 and rEag2 are predominantly expressed in the somatodendritic compartment of retinal neurons. In addition, we presented evidence suggesting that rEag1 channels may be expressed in the GABAergic amacrine cell. Finally, based on their different immunostaining patterns over the inner region of the retina, we propose that compared to rEag2, rEag1 expression encompasses a significantly broader range of the somatodendritic compartment of the retinal ganglion cell.

Functional analysis of hepatitis B virus pre-s deletion variants associated with hepatocellular carcinoma

BackgroundNaturally occurring pre-S deletion mutants have been identified in hepatitis B carriers and shown to be associated with the development of hepatocellular carcinoma. The phenotypes of these pre-S deletion genomes remain unclear, and they were investigated in this study.MethodsThe pre-S deletion genomes: (1) pre-S1 deletion, (2) deletion spanning pre-S1 and pre-S2, (3) pre-S2 N-terminal deletion, and (4) pre-S2 internal deletion were constructed and analyzed by transfection into Huh-7 cells.ResultsFunctional analyses reveal that these mutants were divided into two groups: S promoter deletion and non-S promoter deletion variants. Compared with the wild-type genome, S promoter deletion variants led to an inverse ratio of pre-S1 mRNA and pre-S2/S mRNA, and intracellular accumulation of surface proteins. An interesting finding is that a small amount of L proteins was detected in the medium from S promoter deletion variant-transfected cells. Non-S promoter deletion variants conversely displayed a wild-type like mRNA and protein pattern. The secretion of surface proteins from non-S promoter deletion variants was inhibited less than from S promoter deletion variant. Immunofluorescence analysis showed mutant surface proteins colocalized with ER and exhibited an atypical distribution: granular staining pattern in the S-promoter deletion variants and perinuclear staining pattern in the non-S promoter deletion variants.ConclusionThis study shows that these pre-S deletion genomes exhibit two different phenotypes in mRNA transcription, surface protein expression and secretion. This diversity seems to result from the deletion of S promoter rather than result from the deletion of pre-S1 or pre-S2.

Toluene disrupts synaptogenesis in cultured hippocampal neurons.

Prenatal toluene exposure may lead to significant developmental neurotoxicity known as fetal solvent syndrome. Emerging evidence suggests that toluene embryopathy may arise from an elusive deviation of the neurogenesis process. One key event during neural development is synaptogenesis, which is essential for the progression of neuronal differentiation and the establishment of neuronal network. We therefore aim to test the hypothesis that toluene may interfere with synaptogenesis by applying toluene to cultured hippocampal neurons dissected from embryonic rat brains. In the presence of toluene, hippocampal neurons displayed a significant loss of the immunostaining of synapsin and densin-180 punctas. Notably, a dramatic reduction was also discerned for the colocalization of the two synaptic markers. Moreover, Western blotting analyses revealed that toluene exposure resulted in considerable down-regulation of the expression of synapse-specific proteins. None of the preceding observations can be attributed to toluene-induced cell death effects, since toluene treatments failed to affect the viability of hippocampal neurons. Overall, our data are consistent with the idea that toluene may alter the expression and localization of essential synaptic proteins, thereby leading to a disruption of synapse formation and maintenance.