Views of Hong Kong Chinese medicine practitioners on the application of the "Chinese Medicine Anti-epidemic Plans" prepared by the Chinese medicine expert group of central authorities: a focus group study

BACKGROUND

Drawing on the extensive utilization of traditional Chinese medicine (TCM) to combat COVID-19 in Mainland China, experts designed a series of TCM anti-epidemic strategies. This study aims to understand Hong Kong CM practitioners' application of and opinions on the "Chinese Medicine Anti-epidemic Plans."

METHODS

Online focus group interviews were conducted, and purposive sampling was employed to invite 22 CM practitioners to voluntarily participate in three interview sessions. The interviews were audio recorded, then transcribed verbatim. The transcripts were analyzed using template analysis.

RESULTS

Three themes were derived: (1) facilitators of the "Chinese Medicine Anti-epidemic Plans," (2) barriers of the "Chinese Medicine Anti-epidemic Plans," and (3) expectations on improving the "Chinese Medicine Anti-epidemic Plans." The participants could obtain relevant information from various sources, which highlights the value of the plans for TCM medicinal cuisine and non-pharmacologic therapies and guiding junior CM practitioners, supplementing Western medicine interventions, and managing Chinese herb reserves in clinics. However, the barriers included the lack of a specialized platform for timely information release, defective plan content, limited reference value to experienced CM practitioners, and lack of applicability to Hong Kong. The expectations of the CM practitioners for improving the plans were identified based on the barriers.

CONCLUSIONS

To enhance the implementation of the anti-epidemic plans, CM practitioners in Hong Kong expect to utilize a specific CM platform and refine the plans to ensure that they are realistic, focused, comprehensive, and tailored to the local context.

Self-Administered Acupressure for Probable Knee Osteoarthritis in Middle-Aged and Older Adults: A Randomized Clinical Trial

Importance

The effects of self-administered acupressure (SAA) on knee osteoarthritis (OA) pain remain unclear.

Objective

To evaluate the effectiveness of SAA taught via a short training course on reducing knee OA pain in middle-aged and older adults.

Design, Setting, and Participants

This randomized clinical trial was conducted among community-dwelling individuals in Hong Kong who were aged 50 years or older with probable knee OA from September 2019 to May 2022.

Interventions

The intervention included 2 training sessions for SAA with a brief knee health education (KHE) session, in which participants practiced acupressure twice daily for 12 weeks. The control group (KHE only) received only education about maintaining knee health on the same schedule and duration.

Main Outcomes and Measures

The primary outcome was the numerical rating scale (NRS) pain score at 12 weeks. Other outcomes included Western Ontario and McMaster University Osteoarthritis Index, Short Form 6 Dimensions (SF-6D), Timed Up and Go, and Fast Gait Speed tests.

Results

A total of 314 participants (mean [SD] age, 62.7 [4.5] years; 246 [78.3%] female; mean [SD] knee pain duration, 7.3 [7.6] years) were randomized into intervention and KHE-only groups (each 157). At week 12, compared with the KHE-only group, the intervention group had a significantly greater reduction in NRS pain score (mean difference [MD], -0.54 points; 95% CI, -0.97 to -0.10 points; P = .02) and higher enhancement in SF-6D utility score (MD, 0.03 points; 95% CI, 0.003 to 0.01 points; P = .03) but did not have significant differences in other outcome measures. The cost-effectiveness acceptability curve demonstrated a greater than 90% probability that the intervention is cost-effective at a willingness to pay threshold of 1 GDP per capita.

Conclusions and Relevance

In this randomized clinical trial, SAA with a brief KHE program was efficacious and cost-effective in relieving knee pain and improving mobility in middle-aged and older adults with probable knee OA.

Trial Registration

ClinicalTrials.gov Identifier: NCT04191837.

Effects of transcranial pulse stimulation on autism spectrum disorder: a double-blind, randomized, sham-controlled trial

Transcranial pulse stimulation has been proven effective to improve cognition, memory and depressive symptoms of Alzheimer's disease, but supporting evidence on other neurological diseases or neuropsychiatric disorders remains limited. This study aimed to investigate the effects of transcranial pulse stimulation on the right temporoparietal junction, which is a key node for social cognition for autism spectrum disorder, and to examine the association between transcranial pulse stimulation and executive and social functions. This double-blinded, randomized, sham-controlled trial included 32 participants (27 males), aged 12-17 years with autism spectrum disorder. All eligible participants were randomized into either the verum or sham transcranial pulse stimulation group, on a 1:1 ratio, based on the Childhood Autism Rating Scale screening score. Sixteen participants received six verum transcranial pulse stimulation sessions (energy level: 0.2-0.25 mJ/mm2; pulse frequency: 2.5-4.0 Hz, 800 pulse/session) in 2 weeks on alternate days. The remaining 16 participants received sham transcranial pulse stimulation. The primary outcome measure included Childhood Autism Rating Scale score changes, evaluated by parents, from baseline to 3-month follow-ups. Secondary outcomes included a self-reported questionnaire responded to by parents and cognitive tests responded to by participants. A licensed mental health professional evaluated clinical global impression severity, improvement, efficacy and total score. Results revealed significant interactions in Childhood Autism Rating Scale and other secondary outcomes. Significant group and time effects were found in most secondary outcomes. Additionally, significant differences were found between the transcranial pulse stimulation and sham transcranial pulse stimulation groups in Childhood Autism Rating Scale and clinical global impression improvement and total score immediately after 2 weeks of transcranial pulse stimulation intervention (all P < 0.05), and effects were sustainable at 1- and 3-month follow-up, compared with baseline. The effect size of Childhood Autism Rating Scale (d = 0.83-0.95) and clinical global impression improvement (d = 4.12-4.37) were large to medium immediately after intervention and sustained at 1-month post-stimulation; however, the effects were reduced to small at 3-month post-stimulation (d = 2.31). These findings indicated that transcranial pulse stimulation over right temporoparietal junction was effective to reduce the core symptoms of autism spectrum disorder, as evidenced by a 24% reduction in the total Childhood Autism Rating Scale score in the verum transcranial pulse stimulation group. Additionally, the clinical global impression total score was reduced by 53.7% in the verum transcranial pulse stimulation group at a 3-month follow-up, compared with the baseline. Participants in the verum transcranial pulse stimulation group had shown substantial improvement at 1- and 3-month follow-ups, compared with baseline, although some of the neuropsychological test results were deemed statistically insignificant. Future replication of this study should include a larger sample derived from multi-nations to determine transcranial pulse stimulation as an alternative top-on treatment option in neuropsychiatry.

The Effectiveness of Electrical Vestibular Stimulation (VeNS) on Symptoms of Anxiety: Study Protocol of a Randomized, Double-Blinded, Sham-Controlled Trial

The prevalence of symptoms of anxiety is increasing, especially during the COVID-19 pandemic. A home use transdermal neurostimulation device might help to minimize the severity of anxiety disorder. To the best of our knowledge, there is no clinical trial using transdermal neurostimulation to treat individuals with symptoms of anxiety in Asia. This gives us the impetus to execute the first study which aims at evaluating the efficacy of Electrical Vestibular Stimulation (VeNS) on anxiety in Hong Kong. This study proposes a two-armed, double-blinded, randomized, sham-controlled trial including the active VeNS and sham VeNS group. Both groups will be measured at baseline (T1), immediately after the intervention (T2), and at the 1-month (T3) and 3-month follow-up (T4). A total of 66 community-dwelling adults aged 18 to 60 with anxiety symptoms will be recruited in this study. All subjects will be computer randomised into either the active VeNS group or the sham VeNS group in a 1:1 ratio. All subjects in each group will receive twenty 30 min VeNS sessions during weekdays, which will be completed in a 4-week period. Baseline measurements and post-VeNS evaluation of the psychological outcomes (i.e., anxiety, insomnia, and quality of life) will also be conducted on all participants. The 1-month and 3-month follow-up period will be used to assess the long-term sustainability of the VeNS intervention. For statistical analysis, ANOVA with repeated measures will be used to analyze data. Missing data were managed with multiple mutations. The level of significance will be set to p < 0.05. Results of this study will be used to determine whether this VeNS device can be considered as a self-help technological device to reduce perceived anxiety in the general population in the community setting. This clinical Trial was registered with the Clinical Trial government, identifier: NCT04999709.

Effects of Transcranial Pulse Stimulation (TPS) on Adults with Symptoms of Depression-A Pilot Randomized Controlled Trial

Transcranial pulse stimulation (TPS) is a recent development in non-invasive brain stimulations (NIBS) that has been proven to be effective in terms of significantly improving Alzheimer patients' cognition, memory, and execution functions. Nonetheless, there is, currently, no trial evaluating the efficacy of TPS on adults with major depression disorder (MDD) nationwide. In this single-blinded, randomized controlled trial, a 2-week TPS treatment comprising six 30 min TPS sessions were administered to participants. Participants were randomized into either the TPS group or the Waitlist Control (WC) group, stratified by gender and age according to a 1:1 ratio. Our primary outcome was evaluated by the Hamilton depression rating scale-17 (HDRS-17). We recruited 30 participants that were aged between 18 and 54 years, predominantly female (73%), and ethnic Chinese from 1 August to 31 October 2021. Moreover, there was a significant group x time interaction (F(1, 28) = 18.8, p < 0.001). Further, when compared with the WC group, there was a significant reduction in the depressive symptom severity in the TPS group (mean difference = -6.60, p = 0.02, and Cohen's d = -0.93). The results showed a significant intervention effect; in addition, the effect was large and sustainable at the 3-month follow-up. In this trial, it was found that TPS is effective in reducing depressive symptoms among adults with MDD.

Evaluating the Safety and Efficacy of Transcranial Pulse Stimulation on Autism Spectrum Disorder: A Double-Blinded, Randomized, Sham-Controlled Trial Protocol

Autistic spectrum disorder (ASD) is a common developmental disorder in children. The latest non-intrusive brain stimulation (NIBS) technology-transcranial pulse stimulation (TPS)-has been proven effective in older adults with mild neurocognitive disorders and adults with major depressive disorder. Nonetheless, there is so far no robust randomized controlled trial (RCT) conducted on adolescents with ASD nationwide. This study proposes a two-armed (verum TPS group vs. sham TPS group), double-blinded, randomized, sham-controlled trial. Both groups will be measured at four timepoints, namely, baseline (T1), 2 weeks immediately after post-TPS intervention (T2), and at the 1-month (T3) and 3-month (T4) follow-ups. Thirty-four subjects, aged between 12 and 17, diagnosed with ASD will be recruited in this study. All subjects will be computerized randomised into the verum TPS group or the sham TPS group on a 1:1 ratio. All subjects will undertake functional MRI (fMRI) before and after the 2-weeks TPS interventions, which will be completed in 2 weeks' time. This will be the first RCT evaluating the efficacy of TPS adolescents with ASD in Hong Kong. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT05408793.

Effects of Transcranial Pulse Stimulation (TPS) on Young Adults With Symptom of Depression: A Pilot Randomised Controlled Trial Protocol

Background

Since the emergence of the COVID-19 pandemic, there have been lots of published work examining the association between COVID-19 and mental health, particularly, anxiety and depression in the general populations and disease subpopulations globally. Depression is a debilitating disorder affecting individuals' level of bio-psychological-social functioning across different age groups. Since almost all studies were cross-sectional studies, there seems to be a lack of robust, large-scale, and technological-based interventional studies to restore the general public's optimal psychosocial wellbeing amidst the COVID-19 pandemic. Transcranial pulse stimulation (TPS) is a relatively new non-intrusive brain stimulation (NIBS) technology, and only a paucity of studies was conducted related to the TPS treatment on older adults with mild neurocognitive disorders. However, there is by far no study conducted on young adults with major depressive disorder nationwide. This gives us the impetus to execute the first nationwide study evaluating the efficacy of TPS on the treatment of depression among young adults in Hong Kong.

Methods

This study proposes a two-armed single-blinded randomised controlled trial including TPS as an intervention group and a waitlist control group. Both groups will be measured at baseline (T1), immediately after the intervention (T2), and at the 3- month follow-up (T3).

Recruitment

A total of 30 community-dwelling subjects who are aged 18 and above and diagnosed with major depressive disorder (MDD) will be recruited in this study. All subjects will be computer randomised into either the intervention group or the waitlist control group, balanced by gender and age on a 1:1 ratio.

Intervention

All subjects in each group will have to undertake functional MRI (fMRI) before and after six 30-min TPS sessions, which will be completed in 2 weeks' time.

Outcomes

Baseline measurements and post-TPS evaluation of the psychological outcomes (i.e., depression, cognition, anhedonia, and instrumental activities of daily living) will also be conducted on all participants. A 3-month follow-up period will be usedto assess the long-term sustainability of the TPS intervention. For statistical analysis, ANOVA with repeated measures will be used to analyse data. Missing data were managed by multiple mutations. The level of significance will be set to p < 0.05.

Significance of the Study

Results of this study will be used to inform health policy to determine whether TPS could be considered as a top treatment option for MDD.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT05006365.

Effects of Urban Green Space on Cardiovascular and Respiratory Biomarkers in Chinese Adults: Panel Study Using Digital Tracking Devices

Background

The health benefits of urban green space have been widely reported in the literature; however, the biological mechanisms remain unexplored, and a causal relationship cannot be established between green space exposure and cardiorespiratory health.

Objective

Our aim was to conduct a panel study using personal tracking devices to continuously collect individual exposure data from healthy Chinese adults aged 50 to 64 years living in Hong Kong.

Methods

A panel of cardiorespiratory biomarkers was tested each week for a period of 5 consecutive weeks. Data on weekly exposure to green space, air pollution, and the physical activities of individual participants were collected by personal tracking devices. The effects of green space exposure measured by the normalized difference vegetation index (NDVI) at buffer zones of 100, 250, and 500 meters on a panel of cardiorespiratory biomarkers were estimated by a generalized linear mixed-effects model, with adjustment for confounding variables of sociodemographic characteristics, exposure to air pollutants and noise, exercise, and nutrient intake.

Results

A total of 39 participants (mean age 56.4 years, range 50-63 years) were recruited and followed up for 5 consecutive weeks. After adjustment for sex, income, occupation, physical activities, dietary intake, noise, and air pollution, significant negative associations with the NDVI for the 250-meter buffer zone were found in total cholesterol (–21.6% per IQR increase in NDVI, 95% CI –32.7% to –10.6%), low-density lipoprotein (–14.9%, 95% CI –23.4% to –6.4%), glucose (–11.2%, 95% CI –21.9% to –0.5%), and high-sensitivity C-reactive protein (–41.3%, 95% CI –81.7% to –0.9%). Similar effect estimates were found for the 100-meter and 250-meter buffer zones. After adjustment for multiple testing, the effect estimates of glucose and high-sensitivity C-reactive protein were no longer significant.

Conclusions

The health benefits of green space can be found in some metabolic and inflammatory biomarkers. Further studies are warranted to establish the causal relationship between green space and cardiorespiratory health.

Electromoxibustion for knee osteoarthritis in older adults: A pilot randomized controlled trial

BACKGROUND

Electromoxibustion devices are commercially available and can be self-administered by patients. Nevertheless, little is known about the effectiveness and potential burn injury of these devices as this topic is under-investigated.

OBJECTIVE

To assess the preliminary effects and safety of an electromoxibustion (EM) device for improving knee pain and joint functions in older adults with knee osteoarthritis (KOA).

DESIGN, SETTING, PARTICIPANTS AND INTERVENTION

This was a pilot two-armed assessor-blinded randomized controlled trial to assess the effects of electromoxibustion (EM) on older adults with KOA. A total of 38 subjects aged 60 or above, with KOA for 3 months or above were recruited. Participants were randomized to the EM group or the knee health education group. The intervention group (n = 21) received 12 sessions of EM spanning across four weeks, while the control group (n = 17) received two sessions of knee health education.

MAIN OUTCOME MEASURES

Primary outcome included the pain severity Numerical Rating Scale (NRS) at baseline and week 4. Secondary outcomes included the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Short-Form Six-Dimension (SF6D), Timed Up & Go Test (TUG) and Fast Speed Gait (FSG).

RESULTS

Both groups showed a decreasing trend in knee pain intensity by NRS at post-intervention. There were also trends of improvement in the WOMAC score, TUG score, FGS test score and SF-6D score at week 4. Only a small between-group effect size (d = 0.13) was found, but medium between-group effects sizes were found in the WOMAC total score (d = 0.40) and WOMAC functional sub-score (d = 0.51). However, the differences were not statistically significant.

CONCLUSION

This study suggested that EM may be beneficial for KOA in older adults, particularly in terms of improving knee function. Replication of similar studies in larger RCTs is warranted to confirm the effectiveness of EM on reducing pain and knee function of older adults with KOA.

TRAIL REGISTRATION NUMBER

NCT04034394.

Loss of Fas apoptosis inhibitory molecule leads to spontaneous obesity and hepatosteatosis

Altered hepatic lipogenesis is associated with metabolic diseases such as obesity and hepatosteatosis. Insulin resistance and compensatory hyperinsulinaemia are key drivers of these metabolic imbalances. Fas apoptosis inhibitory molecule (FAIM), a ubiquitously expressed antiapoptotic protein, functions as a mediator of Akt signalling. Since Akt acts at a nodal point in insulin signalling, we hypothesize that FAIM may be involved in energy metabolism. In the current study, C57BL/6 wild-type (WT) and FAIM-knockout (FAIM-KO) male mice were fed with normal chow diet and body weight changes were monitored. Energy expenditure, substrate utilization and physical activities were analysed using a metabolic cage. Liver, pancreas and adipose tissue were subjected to histological examination. Serum glucose and insulin levels and lipid profiles were determined by biochemical assays. Changes in components of the insulin signalling pathway in FAIM-KO mice were examined by immunoblots. We found that FAIM-KO mice developed spontaneous non-hyperphagic obesity accompanied by hepatosteatosis, adipocyte hypertrophy, dyslipidaemia, hyperglycaemia and hyperinsulinaemia. In FAIM-KO liver, lipogenesis was elevated as indicated by increased fatty acid synthesis and SREBP-1 and SREBP-2 activation. Notably, protein expression of insulin receptor beta was markedly reduced in insulin target organs of FAIM-KO mice. Akt phosphorylation was also lower in FAIM-KO liver and adipose tissue as compared with WT controls. In addition, phosphorylation of insulin receptor substrate-1 and Akt2 in response to insulin treatment in isolated FAIM-KO hepatocytes was also markedly attenuated. Altogether, our data indicate that FAIM is a novel regulator of insulin signalling and plays an essential role in energy homoeostasis. These findings may shed light on the pathogenesis of obesity and hepatosteatosis.

Neuroprotective effects of minocycline on double-stranded RNA-induced neurotoxicity in cultured cortical neurons

1. Minocycline, memantine,and glycoconjugate were assessed for their ability to protect cultured primary cortical neurons against double-stranded RNA-induced neurotoxicity. 2. Minocycline but not memantine or glycoconjugate protected cultured cells and warrants further investigation.

A systemic review of human papillomavirus studies: global publication comparison and research trend analyses from 1993 to 2008

The term "human papillomavirus" has been used as the keyword during searching titles, abstracts, and keywords based on the online version of Science Citation Index (SCI), Web of Science from 1993 to 2008. Twelve document types were found among the 14,943 papers published in 1,072 journals that were listed in 99 SCI subject categories. All the articles referring to human papillomavirus were assessed by using the following aspects: characteristics of publication output, distribution of output in journals, publication output of source country, source institute, and analysis of word clusters in title, author keywords, and keywords plus. The results have shown that the USA ranked first using five publication indicators including total, single country, international, first author, and corresponding author publications. China has had the sharpest rise of publications since 2004. The top four European countries in 2008 were France, Germany, the UK, and Italy, respectively. Trend studies with word cluster analysis were performed with regards to the areas of immunology, screening methodology, behavioral sciences, economics, and meta-analysis. All those areas have shown a sharp upward rise since 2004. In addition, hypermethylation-induced inactivation of the p16 gene in the early stages of oncogenesis has been getting more interest in recent years.

Removal of Cr(VI) from aqueous solutions using agricultural waste 'maize bran'

Novel biosorbent 'maize bran' has been successfully utilized for the removal of Cr(VI) from aqueous solution. The effect of different parameters such as contact time, sorbate concentration, pH of the medium and temperature were investigated and maximum uptake of Cr(VI) was 312.52 (mgg(-1)) at pH 2.0, initial Cr(VI) concentration of 200mgL(-1) and temperature of 40 degrees C. Effect of pH showed that maize bran was not only removing Cr(VI) from aqueous solution but also reducing toxic Cr(VI) into less toxic Cr(III). The sorption kinetics was tested with first order reversible, pseudo-first order and pseudo-second order reaction and it was found that Cr(VI) uptake process followed the pseudo-second order rate expression. Mass transfer of Cr(VI) from bulk to the solid phase (maize bran) was studied at different temperatures. Different thermodynamic parameters, viz., DeltaG degrees , DeltaH degrees and DeltaS degrees have also been evaluated and it has been found that the sorption was feasible, spontaneous and endothermic in nature. The Langmuir and Freundlich equations for describing sorption equilibrium were applied and it was found that the process was well described by Langmuir isotherm. Desorption studies was also carried out and found that complete desorption of Cr(VI) took place at pH of 9.5.

Infrared thermography to mass-screen suspected SARS patients with fever

Fever greater than 38 degrees C is a cardinal sign of patients with the severe acute respiratory syndromes (SARS). To reduce the risk of nosocomial cross infections, screening all patients and visitors who visit hospitals and clinics for fever at the entrance of every hospital building has become a standard protocol in Taiwan during the SARS epidemic from mid-April to mid-June 2003. We used a digital infrared thermal imaging (DITI) system (Telesis Spectrum 9000 MB) to conduct mass screening of patients and visitors who entered the hospital to identify those with fever. The DITI system has two components: a sensor head and a PC imaging workstation. The sensor head is an optic-mechanical device which consists of imagining optics for focusing the infrared source information on the infrared detector. The infrared images are further converted into electrical signals, which are then processed for real-time display on the monitor. During the period from April 13 to May 12 2003, 72,327 outpatients and visitors entered Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan. A total of 305 febrile patients (0.42%) was detected by infrared thermography. Among them, three probable SARS patients were identified after thorough studies including contact history, laboratory tests and radiology examinations. The findings suggests that infrared thermography was an effective and reliable tool ideal for mass-screening patients with fever in the initial phase of screening for SARS patients at a busy hospital which sees approximately 3,000 outpatients every weekday during the SARS epidemic.

Involvement of nuclear factor-kappaB in lipoteichoic acid-induced cyclooxygenase-2 expression in RAW 264.7 macrophages

We have investigated the role of protein kinase C (PKC) and nuclear factor-kappaB (NF-kappaB) in cyclooxygenase-2 (COX-2) expression caused by Staphylococcus aureus lipoteichoic acid in RAW 264.7 macrophages. A phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and a phosphatidylinositol-phospholipase C (PI-PLC) inhibitor (U-73122) attenuated lipoteichoic acid-induced COX-2 expression, while a phosphatidate phosphohydrolase inhibitor (propranolol) had no effect. Two PKC inhibitors (Go 6976 and Ro 31-8220) and the NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), also attenuated lipoteichoic acid-induced COX-2 expression. Lipoteichoic acid resulted in a decrease in PKC activity in the cytosol and an increase in PKC activity in membranes. The lipoteichoic acid-induced translocation of p65 NF-kappaB from the cytosol to the nucleus was inhibited by D-609, U-73122, Go 6976, Ro 31-8220, and PDTC, but not by propranolol. The results suggested that lipoteichoic acid might have activated PC-PLC and PI-PLC to induce PKC activation, which in turn initiated NF-kappaB activation, and finally induced COX-2 expression in RAW 264.7 macrophages.

Prevention of the areca nut extract-induced unscheduled DNA synthesis of gingival keratinocytes by vitamin C and thiol compounds

There are about 600 million betel quid (BQ) chewers in the world. BQ chewing is the major risk factor of oral cancer in India, Taiwan, South Africa and numerous other countries. Areca nut (AN) extract, the main component of BQ, exerts cytotoxicity and genotoxicity to several types of cells. In the present study, AN extract induced the unscheduled DNA synthesis (UDS) of gingival keratinocytes (GK). Vitamin C, at concentration of 50 and 200 microg/ml prevented the AN-induced UDS by 41 and 56%, respectively. Glutathione (GSH, 1-3 mM) and N-acetyl-L-cysteine (NAC, 1-3 mM) also protected the AN-induced UDS by 89-100 and 76-90%. These preventive effects were not due to cytotoxicity as analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Deferoxamine (20 and 30 mM), an iron chelator and a free radical scavenger, also prevented AN extract induced UDS of GK by 30-55%. On the contrary, banthocuproine (50-200 microM, a copper chelator) and 1,10-phenanthroline (50, 100 microM, a lipid permeable iron chelator), lacked preventive effects. Specific reactive oxygen species scavengers such as dimethyl-sulfoxide (2%), mannitol (10-20 mM), dimethylthiourea (10-20 mM), pyruvate (10 mM), catalase (200 and 400 U/ml), and superoxide dismutase (50 and 200 U/ml) also lacked these preventive effects. Moreover, higher concentrations of H(2)O(2) (0.5-1 mM) inhibited the basal levels of UDS by 19-37%. Interestingly, NAC, GSH, Vitamin C and deferoxamine cannot prevent the AN-induced morphological changes of GK at similar concentrations. These results reveal that AN extract-induced UDS of GK is associated with free radical reactions. Possibly different ingredients of AN is responsible for genotoxicity and cytotoxicity. Vitamin C, GSH and NAC may be potentially used in the future for chemoprevention of BQ chewing related oral mucosal lesions.

Regulation of sodium-calcium exchange and mitochondrial energetics by Bcl-2 in the heart of transgenic mice

Our previous work in cultured cells has shown that the maintenance of mitochondrial Ca(2+) homeostasis is essential for cell survival, and that the anti-apoptotic protein Bcl-2 is able to maintain a threshold level of mitochondrial Ca(2+) by the inhibition of permeability transition. To test whether Bcl-2 also affects the mitochondrial Na(+)-Ca(2+) exchange (NCE), a major efflux pathway for mitochondrial Ca(2+), studies using transgenic mice that overexpress Bcl-2 in the heart have been performed. NCE activity was determined as the Na(+)-dependent Ca(2+) efflux in the isolated mitochondria. Overexpression of Bcl-2 led to a significant reduction of NCE activity as well as increased resistance to permeability transition in the mitochondria of transgenic heart. This was accompanied by increased matrix Ca(2+) level, enhanced formation of NADH and enhanced oxidation of pyruvate, an NAD(+)-linked substrate. Furthermore, there was induction of cellular Ca(2+) transport proteins including the Na(+)-Ca(2+) exchanger of the sarcolemma (NCX). Bcl-2 not only stimulates NCX expression in the sarcolemma but also attenuates the Na(+)-Ca(2+) exchange in the mitochondria. These results are consistent with the protection by Bcl-2 against apoptosis in heart following ischemia/reperfusion.

Glutathione peroxidase-1 deficiency leads to increased nuclear light scattering, membrane damage, and cataract formation in gene-knockout mice

PURPOSE

Previous in vitro studies with transgenic and gene-knockout mice have shown that lenses with elevated levels of glutathione peroxidase (GPX)-1 activity are able to resist the cytotoxic effect of H(2)O(2), compared with normal lenses and lenses from GPX-1-deficient animals. The purpose of this study was to investigate the functional role of this enzyme in antioxidant mechanisms of lens in vivo by comparing lens changes of gene-knockout mice with age-matched control animals.

METHODS

In vivo lens changes were monitored by slit lamp biomicroscopy, and enucleated lenses were examined under a stereomicroscope in gene-knockout animals and age-matched control animals ranging in age from 3 weeks to 18 months. Transmission (TEM) and confocal microscopy were performed on different regions of lenses after the mice were killed at various times.

RESULTS

Slit lamp images showed an increase in nuclear light scattering (NLS) in gene-knockout mice compared with control animals. TEM revealed changes in the nucleus as early as 3 weeks of age by the appearance of waviness of fiber membranes. With increasing age, there was greater distortion of fiber membranes and distension of interfiber space at the apex of fiber cells compared with control mice. The changes in nuclear fiber membranes were even more dramatic, as observed by confocal microscopy, which was performed on thicker sections. In contrast to the changes in the lens nucleus, the morphology of the epithelium and superficial cortex remained unchanged in knockout animals during the same experimental period, consistent with slit lamp observations. Stereomicroscopy of ex vivo lenses demonstrated a significant increase in opacification in gene-knockout mice relative to control animals of the same age. This effect became evident in mice aged 5 to 9.9 months and persisted thereafter in older animals, resulting in mature cataracts after 15 months.

CONCLUSIONS

The results demonstrate the critical role of GPX-1 in antioxidant defense mechanisms of the lens nucleus. The increased NLS appears to be associated with damage to fiber membranes in the nucleus, which is particularly susceptible to oxidative challenge because of the deficiency of GPX-1. It is suggested that the lens membrane changes in the knockout animals may be due to the formation of lipid peroxides, which serve as substrates for GPX-1. Cataract development in gene-knockout mice appeared to progress from focal opacities, apparent at an earlier age, to lamellar cataracts between 6 and 10 months, and finally to complete opacification in animals older than 15 months. This is the first reported phenotype in GPX-1-knockout mice.

Advanced glycosylation end products induce nitric oxide synthase expression in C6 glioma cells: involvement of a p38 MAP kinase-dependent mechanism

The mitogen-activated protein kinase (MAPK) pathway is believed to function as an important mediator of inducible nitric oxide synthase (iNOS) expression. In the present study, we investigated the role of the p38 MAPK signaling pathway in advanced glycosylation end products (AGEs)-induced iNOS expression in C6 glioma cells. AGEs caused a dose-dependent increase of nitrite accumulation in C6 glioma cells. The AGEs-stimulated nitrite production from C6 glioma cells was inhibited by actinomycin D, cyclohexamide, and the NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), suggesting that the increase of AGEs-induced nitrite release is due to iNOS up-regulation. Consistently, treatment of C6 glioma cells with AGEs induced iNOS protein expression. AGEs-stimulated nitrite production was inhibited by pretreatment of C6 glioma cells with anti-AGEs antibodies (1:100 or 1:50). The tyrosine kinase inhibitor (genistein and tyrphostin), the Ras-farnesyl transferase inhibitor (FPT inhibitor-II), or the p38 MAPK inhibitor (SB203580) suppressed AGEs-induced iNOS expression and nitrite release from C6 glioma cells. AGEs activated p38 MAPK in C6 glioma cells, and this effect was blocked by genistein (20 microM), tyrphostin (30 microM), FPT inhibitor-II (20 microM), and SB203580 (10 microM). Taken together, our data suggest that AGEs may activate the pathways of tyrosine kinase and Ras to induce p38 MAPK activation, which in turn induces iNOS expression and NO production in C6 glioma cells.

Induction of cyclooxygenase-2 protein by lipoteichoic acid from Staphylococcus aureus in human pulmonary epithelial cells: involvement of a nuclear factor-kappa B-dependent pathway

1. This study investigated the role of protein kinase C (PKC) and transcription factor nuclear factor-kappaB (NF-kappaB) in cyclooxygenase-2 (COX-2) expression caused by lipoteichoic acid (LTA), a cell wall component of the gram-positive bacterium Staphylococcus aureus, in human pulmonary epithelial cell line (A549). 2. LTA caused dose- and time-dependent increases in COX-2 expression and COX activity, and a dose-dependent increase in PGE(2) release in A549 cells. The LTA-induced increases in COX-2 expression and COX activity were markedly inhibited by dexamethasone, actinomycin D or cyclohexamide, but not by polymyxin B, which binds and inactivates endotoxin. 3. The phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and the phosphatidate phosphohydrolase inhibitor (propranolol) reduced the LTA-induced increases in COX-2 expression and COX activity, while phosphatidylinositol-phospholipase C inhibitor (U-73122) had no effect. The PKC inhibitors (Go 6976, Ro 31-8220 and GF 109203X) and NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), also attenuated the LTA-induced increases in COX-2 expression and COX activity. 4. Treatment of A549 cells with LTA caused an increase in PKC activity in the plasma membrane; this stimulatory effect was inhibited by D-609, propranolol, or Go 6976, but not by U-73122. 5. Exposure of A549 cells to LTA caused a translocation of p65 NF-kappaB from the cytosol to the nucleus and a degradation of IkappaB-alpha in the cytosol. Treatment of A549 cells with LTA caused NF-kappaB activation by detecting the formation of NF-kappaB-specific DNA-protein complex in the nucleus; this effect was inhibited by dexamethasone, D-609, propranolol, Go 6976, Ro 31-8220, or PDTC. 6. These results suggest that LTA might activate PC-PLC and phosphatidylcholine-phospholipase D to induce PKC activation, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE(2) release in human pulmonary epithelial cell line.

Molecular mechanisms of apoptosis induced by magnolol in colon and liver cancer cells

Magnolol has been reported to have anticancer activity. In this study we found that treatment with 100 microm magnolol induced apoptosis in cultured human hepatoma (Hep G2) and colon cancer (COLO 205) cell lines but not in human untransformed gingival fibroblasts and human umbilical vein endothelial cells. Our investigation of apoptosis in Hep G2 cells showed a sequence of associated intracellular events that included (a) increased cytosolic free Ca(2+); (b) increased translocation of cytochrome c (Cyto c) from mitochondria to cytosol; (c) activation of caspase 3, caspase 8, and caspase 9; and (d) downregulation of bcl-2 protein. Pretreatment of the cells with the phospholipase C inhibitor 1-[6-[[(17 beta)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1 H-pyrrole-2,5-dione (U73122) or the intracellular chelator of Ca(2+) 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA/AM) inhibited the subsequent magnolol augmentation of [Ca(2+)](i) and also the activation of caspase-8 and caspase-9, so that the occurrence of apoptosis in those cells was greatly reduced. Pretreatment of the cells with ZB4 (which disrupts the Fas response mechanism) also decreased the subsequent magnolol-induced caspase-8 activation and reduced the occurrence of apoptosis. We interpreted these findings to indicate that the above-listed sequence of intracellular events led to the apoptosis seen in Hep G2 cells and that [Ca(2+)](i), Cyto c, and Fas function as intracellular signals to coordinate those events.

Areca nut extract and arecoline induced the cell cycle arrest but not apoptosis of cultured oral KB epithelial cells: association of glutathione, reactive oxygen species and mitochondrial membrane potential

There are 600 million betel quid (BQ) chewers in the world. BQ chewing is a major etiologic factor of oral cancer. Areca nut (AN) and arecoline may inhibit the growth of oral mucosal fibroblasts (OMF) and keratinocytes. In this study, AN extract (100-800 microg/ml) and arecoline (20-120 microM) inhibited the growth of oral KB cells by 36-90 and 15-75%, respectively. Exposure to arecoline (> 0.2 mM) for 24 h induced G(2)/M cell cycle arrest of OMF and KB cells. Areca nut extract (> 400 microg/ml) also induced G(2)/M arrest of KB cells, being preceded by S-phase arrest at 7-h of exposure. No evident sub-G(0)/G(1) peak was noted. Marked retraction and intracellular vacuoles formation of OMF and KB cells were observed. Glutathione (GSH) level, mitochondrial membrane potential (Deltabetam) and H(2)O(2) production of KB cells were measured by flow cytometry. GSH level [indicated by 5-chloromethyl-fluorescein (CMF) fluorescence] was depleted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml), with increasing the percentage of cells in low CMF fluorescence. By contrast, arecoline (0.1-1.2 mM) and AN extract (800-1200 microg/ml) induced decreasing and increasing H(2)O(2) production (by 2',7'-dichloro- fluorescein fluorescence), respectively. Hyperpolarization of Deltabetam (increasing of rhodamine uptake) was noted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml). AN extract (100- 1200 microg/ml) and arecoline (0.1-1.2 mM) induced little DNA fragmentation on KB cells within 24 h. These results indicate that AN ingredients are crucial in the pathogenesis of oral submucous fibrosis (OSF) and oral cancer by differentially inducing the dysregulation of cell cycle control, Deltabetam, GSH level and intracellular H(2)O(2) production, these events being not coupled with cellular apoptosis.

Genomic organization and chromosomal localization of the Asna1 gene, a mouse homologue of a bacterial arsenic-translocating ATPase gene

The plasmid encoded ArsA ATPase in Escherichia coli is the catalytic component of an oxyanion pump that is responsible for resistance to arsenicals and antimonials. Arsenite or antimonite allosterically activates the ArsA ATPase activity. In this paper, we report the cloning and characterization of the mouse homologue (Asna1) of the bacterial arsA gene. The Asna1 gene encodes an open reading frame of 348 amino acids and exhibits 27% identity to the bacterial ArsA protein and 99% similarity to its human counterpart (hASNA-1). The Asna1 mRNA is a approximately 1.3 kb transcript and is present at high levels in kidney and testis, moderate levels in brain, liver, lung and skin, and low levels in heart, small intestine, spleen, stomach, and thymus. A negligible amount of Asna1 transcript is detected in skeletal muscle. We have also characterized the genomic structure of the Asna1 gene. The gene spans over 7 kb and consists of seven exons and six introns. All splice sites conform to the GT-AG rule, except for the splice donor site of intron 4 that is GC instead of GT. Fluorescence in situ hybridization indicates that the Asna1 gene is localized in the C3-D1 region of mouse chromosome 8.

Cardiac myocytes exposed to anoxia-reoxygenation promote neutrophil transendothelial migration

The goal of the present study was to assess whether cardiac myocytes exposed to anoxia-reoxygenation (A/R) could generate a chemotactic gradient for polymorphonuclear neutrophil (PMN) transendothelial migration. Exposure of neonatal mouse cardiac myocytes to A/R induced an oxidant stress in the myocytes. Supernatants obtained from A/R-conditioned myocytes promoted mouse PMN migration across mouse myocardial endothelial cell monolayers. This increase in PMN transendothelial migration could be prevented if catalase or a platelet-activating factor (PAF) antagonist was added to the supernatants before assay. Supernatants from A/R-conditioned myocytes activated endothelial cells by inducing an intracellular oxidant stress. The oxidant stress and PMN transendothelial migration induced by supernatants from A/R-conditioned myocytes were substantially reduced when endothelial cells derived from manganese superoxide dismutase overexpressing mice were used in the assays. Supernatants from A/R-conditioned myocytes also increased endothelial cell surface levels of E-selectin and intercellular adhesion molecule-1. Our results indicate that cardiac myocytes exposed to A/R can generate a chemotactic gradient, presumably due to production and release of stable oxidants and PAF. The ability of supernatants from A/R-conditioned myocytes to promote PMN transendothelial migration was largely dependent on induction of an oxidant stress in endothelial cells. In addition, these supernatants also induced a proadhesive phenotype in the endothelial cells.

Preparation and crystal structure of the recombinant alpha(1)/alpha(2) catalytic heterodimer of bovine brain platelet-activating factor acetylhydrolase Ib

The intracellular form of mammalian platelet activating factor acetylhydrolase found in brain (PAF-AH Ib) is thought to play a critical role in control in neuronal migration during cortex development. This oligomeric complex consists of a homodimer of the 45 kDa (beta) LIS1 protein, the product of the causative gene for type I lissencephaly, and, depending on the developmental stage and species, one of three possible pairs of two homologous approximately 26 kDa alpha-subunits, which harbor all of the catalytic activity. The exact composition of this complex depends on the expression patterns of the alpha(1) and alpha(2) genes, exhibiting tissue specificity and developmental control. All three possible dimers (alpha(1)/alpha(1), alpha(1)/alpha(2) and alpha(2)/alpha(2)) were identified in tissues. The alpha(1)/alpha(2) heterodimer is thought to play an important role in fetal brain. The structure of the alpha(1)/alpha(1) homodimer was solved earlier in our laboratory at 1.7 A. We report here the preparation of recombinant alpha(1)/alpha(2) heterodimers using a specially constructed bi-cistronic expression vector. The approach may be useful in studies of other systems where pure heterodimers of recombinant proteins are required. The alpha(1)/alpha(2) dimer has been crystallized and its structure was solved at 2.1 A resolution by molecular replacement. These results set the stage for a detailed characterization of the PAF-AH Ib complex.

Changes in expression of antioxidant enzymes affect cell-mediated LDL oxidation and oxidized LDL-induced apoptosis in mouse aortic cells

Transgenic mice overexpressing Cu/Zn superoxide dismutase (hSod1Tg(+/0)) or catalase (hCatTg(+/0)) and knockout mice underexpressing manganese superoxide dismutase (Sod2(+/)(-)) or glutathione peroxidase-1 (Gpx1(-/-)) were used to study the effect of antioxidant enzymes on cell-mediated low density lipoprotein (LDL) oxidation and oxidized LDL (oxLDL)-induced apoptosis. Incubation of LDL with mouse aortic segments or smooth muscle cells (SMCs) resulted in a significant increase in LDL oxidation. However, LDL oxidation was significantly reduced when LDL was incubated with aortic segments and SMCs obtained from hSod1Tg(+/0) and hCatTg(+/0) mice compared with those obtained from wild-type mice. In contrast, LDL oxidation was significantly increased when LDL was incubated with aortic segments and SMCs obtained from Sod2(+/)(-) and Gpx1(-/-) mice. CuSO(4)-oxidized LDL increased DNA fragmentation and caspase activities in the primary cultures of mouse aortic SMCs. However, oxLDL-induced DNA fragmentation and caspase activities were reduced 50% in SMCs obtained from hSod1Tg(+/0) and hCatTg(+/0) mice compared with wild-type control mice. In contrast, oxLDL-induced DNA fragmentation and caspase activities were significantly increased in SMCs obtained from Sod2(+/)(-) and Gpx1(-/-) mice. These findings suggest that overexpression of Cu/Zn superoxide dismutase or catalase reduces cell-mediated LDL oxidation and oxLDL-induced apoptosis, whereas underexpression of manganese superoxide dismutase or glutathione peroxidase-1 increases cell-mediated LDL oxidation and oxLDL-induced apoptosis.

Oxidative stress and liver toxicity in rats and human hepatoma cell line induced by pentachlorophenol and its major metabolite tetrachlorohydroquinone

Pentachlorophenol (PCP) is a pesticide used worldwide in industrial and domestic applications. It is used extensively as biocide and wood preservatives. Metabolic studies carried out in rodents and human liver homogenates have indicated that PCP undergoes oxidative dechlorination to form tetrachlorohydroquinone (TCHQ). Free radical catalyzed tissue injury is thought to play a fundamental role in human disease. In the present study, we examined the effects of PCP and TCHQ on the induction of lipid peroxidation and liver injury in rats. In addition, the cytotoxic dose, cell death mechanisms and related gene expressions induced by PCP and TCHQ were also determined for human hepatoma cell line (Hep G2). The results indicated that more toxic effects could be observed both in rats and human hepatoma cell line treated with TCHQ than its parent compound, PCP. Oxygen species may be involved in the mechanism of TCHQ intoxication since the urinary 8-epi-PGF2alpha and AST, ALT activities can be induced by TCHQ and attenuated by vitamin E treatment. Apoptosis features were found in cells treated with TCHQ but not PCP. TCHQ-induced cell damage may issue signals for the induction of HSPs, the decrease of the bcl/bax protein ratio and the decrease of CAS gene, whereas the PCP-induced damage may not.

Overexpression of Bcl-2 attenuates apoptosis and protects against myocardial I/R injury in transgenic mice

To test whether the antiapoptotic protein Bcl-2 prevents apoptosis and injury of cardiomyocytes after ischemia-reperfusion (I/R), we generated a line of transgenic mice that carried a human Bcl-2 transgene under the control of a mouse alpha-myosin heavy chain promoter. High levels of human Bcl-2 transcripts and 26-kDa Bcl-2 protein were expressed in the hearts of transgenic mice. Functional recovery of the transgenic hearts significantly improved when they were perfused as Langendorff preparations. This protection was accompanied by a threefold decrease in lactate dehydrogenase (LDH) released from the transgenic hearts. The transgenic mice were subjected to 50 min of ligation of the left descending anterior coronary artery followed by reperfusion. The infarct sizes, expressed as a percentage of the area at risk, were significantly smaller in the transgenic mice than in the nontransgenic mice (36.6 +/- 5 vs 69.9 +/- 7.3%, respectively). In hearts subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion, Bcl-2 transgenic hearts had significantly fewer terminal deoxynucleodidyl-transferase nick-end labeling-positive or in situ oligo ligation-positive myocytes and a less prominent DNA fragmentation pattern. Our results demonstrate that overexpression of Bcl-2 renders the heart more resistant to apoptosis and I/R injury.

H(mox-1) constitutes an adaptive response to effect antioxidant cardioprotection: A study with transgenic mice heterozygous for targeted disruption of the Heme oxygenase-1 gene

BACKGROUND

Heme oxygenase-1 (H(mox-1)) has been implicated in protection of cells against ischemia/reperfusion injury.

METHODS AND RESULTS

To examine the physiological role of H(mox-1), a line of heterozygous H(mox-1)-knockout mice was developed by targeted disruption of the mouse H(mox-1) gene. Transgene integration was confirmed and characterized at the protein level. A 40% reduction of H(mox-1) protein occurred in the hearts of H(mox-1)(+/)(-) mice compared with those of wild-type mice. Isolated mouse hearts from H(mox-1)(+/)(-) mice and wild-type controls perfused via the Langendorff mode were subjected to 30 minutes of ischemia followed by 120 minutes of reperfusion. The H(mox-1)(+/)(-) hearts displayed reduced ventricular recovery, increased creatine kinase release, and increased infarct size compared with those of wild-type controls, indicating that these H(mox-1)(+/)(-) hearts were more susceptible to ischemia/reperfusion injury than wild-type controls. These results also suggest that H(mox-1)(+/)(-) hearts are subjected to increased amounts of oxidative stress. Treatment with 2 different antioxidants, Trolox or N:-acetylcysteine, only partially rescued the H(mox-1)(+/)(-) hearts from ischemia/reperfusion injury. Preconditioning, which renders the heart tolerant to subsequent lethal ischemia/reperfusion, failed to adapt the hearts of the H(mox-1)(+/)(-) mice compared with wild-type hearts.

CONCLUSIONS

These results demonstrate that H(mox-1) plays a crucial role in ischemia/reperfusion injury not only by functioning as an intracellular antioxidant but also by inducing its own expression under stressful conditions such as preconditioning.

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

Mitochondrial superoxide production in kainate-induced hippocampal damage

The objective of this study was to determine the role of mitochondrial superoxide radical-mediated oxidative damage in seizure-induced neuronal death. Using aconitase inactivation as an index of superoxide production, we found that systemic administration of kainate in rats increased mitochondrial superoxide production in the hippocampus at times preceding neuronal death. 8-Hydroxy-2-deoxyguanosine, an oxidative lesion of DNA, was also increased in the rat hippocampus following kainate administration. Manganese(III) tetrakis(4-benzoic acid)porphyrin, a catalytic antioxidant, inhibited kainate-induced mitochondrial superoxide production, 8-hydroxy-2-deoxyguanosine formation and neuronal loss in the rat hippocampus. Kainate-induced increases of mitochondrial superoxide production and hippocampal neuronal loss were attenuated in transgenic mice overexpressing mitochondrial superoxide dismutase-2. We propose that these results demonstrate a role for mitochondrial superoxide production in hippocampal pathology produced by kainate seizures.

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

Ketoconazole induces G0/G1 arrest in human colorectal and hepatocellular carcinoma cell lines

Ketoconazole is an oral-antifungal agent that has been used worldwide in the treatment of some hormone-dependent human cancer. In this study, we demonstrated that ketoconazole (20 microM) induced various types of human cancer cell growth arrest in the G0/G1 phase. Our results revealed that ketoconazole-induced growth arrest was more profound in COLO 205 and Hep G2 (with wild-type p53) than in HT 29 (p53 His(273) mutant) and Hep 3B (with deleted p53) cells. The protein levels of p53, p21/Cip1, and p27/Kip1 were significantly elevated by ketoconazole (10 microM) treatment in COLO 205 but not in HT 29 cells. The ketoconazole-induced G0/G1 phase arrest in COLO 205 cells was attenuated by p53-specific antisense oligodeoxynucleotides (20 microM) treatment. These results suggested that the p53-associated signaling pathway is involved in the regulation of ketoconazole-induced cancer cell growth arrest. By Western blot analysis, we demonstrated that cyclin D3 and CDK4 protein but not other G0/G1 phase regulatory protein levels were decreased by ketoconazole-treatment in both COLO 205 and HT 29 cells. Our study provides the basis of molecular mechanisms for ketoconazole in growth inhibition of human cancer cells and such results may have significant applications for cancer chemotherapy.

Different cell death mechanisms and gene expression in human cells induced by pentachlorophenol and its major metabolite, tetrachlorohydroquinone

Pentachlorophenol (PCP) and its salt are used extensively as biocide and wood preservative. Due to improper disposal, PCP has become an environmental pollutant and is now considered to be ubiquitos. Metabolic studies carried out in rodents or human liver homogenate have indicated that PCP undergoes oxidative dechlorination to form tetrachlorohydroquinone (TCHQ). The cytotoxicity, cell death mechanisms and gene expression of PCP and TCHQ are investigated in human liver and bladder cells and show that TCHQ induces apoptosis and DNA genomic fragmentation in bladder cells but not liver cells. No apoptotic features could be induced by treatment of PCP in both cell lines. The concentrations of PCP required to cause 50% cell death in T-24 and Chang liver cells were 5-10-fold greater than the concentrations of TCHQ. Several gene products are important in controlling the apoptotic and necrotic processes. Of these, hsp 70, CAS, bcl-2 and bax were studied. The expression of the hsp70 gene increased significantly (2-3-fold) in cells treated with TCHQ. However, no significant change was found in the cells treated with PCP. The expression of CAS gene decreased significantly in T-24 cells treated with both TCHQ and PCP. Whereas, no significant change was found in Chang liver cells with the same treatment. In addition, the expression of the bcl-2/bax protein decreased significantly in these two cell lines treated with TCHQ but not PCP.

Structure of the GAF domain, a ubiquitous signaling motif and a new class of cyclic GMP receptor

GAF domains are ubiquitous motifs present in cyclic GMP (cGMP)-regulated cyclic nucleotide phosphodiesterases, certain adenylyl cyclases, the bacterial transcription factor FhlA, and hundreds of other signaling and sensory proteins from all three kingdoms of life. The crystal structure of the Saccharomyces cerevisiae YKG9 protein was determined at 1.9 A resolution. The structure revealed a fold that resembles the PAS domain, another ubiquitous signaling and sensory transducer. YKG9 does not bind cGMP, but the isolated first GAF domain of phosphodiesterase 5 binds with K:(d) = 650 nM. The cGMP binding site of the phosphodiesterase GAF domain was identified by homology modeling and site-directed mutagenesis, and consists of conserved Arg, Asn, Lys and Asp residues. The structural and binding studies taken together show that the cGMP binding GAF domains form a new class of cyclic nucleotide receptors distinct from the regulatory domains of cyclic nucleotide-regulated protein kinases and ion channels.

Experimental focal segmental glomerulosclerosis in mice

Although a lot of animal models of proteinuria have been established, proposals for the mechanisms of proteinuria are still controversial. In this work, during an 18-day trial, mice injected with a single dose of adriamycin (AD) rapidly showed combined glomerular albuminuria and immunoglobulinuria, progressively elevated levels of nitrite/nitrate in urine, hypercholesterolemia, abnormal renal function, segmentally or globally glomerular hyalinosis/sclerosis associated with tubular atrophy, enhanced glomerular deposition of immunoglobulins and fibrinogen, augmented expression of matrix components in the whole glomerular tuft, and loss of glomerular negative charge property. These laboratory and pathological features are comparatively similar to those of human focal segmental glomerulosclerosis in the advanced state. Juxtamedullary glomeruli appear to be more susceptible to the AD-related nephrotoxicity than those in the superficial renal cortex. A change in size-dependent glomerular permselectivity may precede a charge-dependent defect in glomeruli in this mouse model of proteinuria. Data in this study confirm the hypothesis of glomerular hyperfiltration involved in the pathogenesis of this chronic glomerulopathy associated with proteinuria in mice. In addition, nitric oxide may play a crucial role in the progression of the chronic glomerulopathy model.

Involvement of immunopathogenic mechanisms in a spontaneously occurring glomerulopathy in mice

Mice have been found to be susceptible to spontaneous renal localization of immune deposits. However, the significance of these immune deposits is still debated. We investigated the immunopathogenesis of a naturally occurring glomerulopathy associated with progressive proteinuria and glomerulosclerosis in 75 BALB/c mice. The mice were divided into five groups of 15 and killed at the age of 1, 3, 6, 12, or 18 months for laboratory and renal pathologic studies. These mice showed persistently increasing serum levels of immune complexes, a marked increase of glomerular immune deposits which were capable of fixing C3, and interstitial infiltration of lymphocytes and plasma cells, followed by the occurrence of proteinuria, mesangiopathy, and glomerulosclerosis. Our findings suggest that an immune system mediated process occurred in the kidneys of the mice tested.

Characterization of the in vitro and in vivo activity of monoclonal antibodies to human IL-18

IL-18 is a cytokine with potent IFN-gamma inducing activities as well as an important mediator of Th1 polarized immune responses. In this study we demonstrated that IL-18 induces the concentration-dependent production of the proinflammatory mediators IFN-gamma, IL-6, and GM-CSF, but not the anti-inflammatory cytokine, IL-10 from peripheral blood lymphocytes in the presence of mitogen. Three neutralizing IL-18 monoclonal antibodies (MAbs) were investigated, one of which (2C10) inhibited IL-18 bioactivity with an IC50 of 0.1 nM and had a K(D) of 3.9 x 10(-11) M. A NOD/SCID mouse model engrafted with human peripheral blood lymphocytes was developed to test the in vivo efficacy of this MAb. The IFN-gamma production induced by LPS administration was inhibited approximately 90% by prior dosing of MAb 2C10. The therapeutic utility of a high-affinity IL-18 MAb may be of benefit in Th1-driven autoimmune diseases such as rheumatoid arthritis and Crohn's Disease, where elevated levels of IL-18 have been observed.

Oxidative stress-associated impairment of proteasome activity during ischemia-reperfusion injury

Numerous studies indicate a role for oxidative stress in the neuronal degeneration and cell death that occur during ischemia-reperfusion injury. Recent data suggest that inhibition of the proteasome may be a means by which oxidative stress mediates neuronal cell death. In the current study, the authors demonstrate that there is a time-dependent decrease in proteasome activity, which is not associated with decreased expression of proteasome subunits, after cerebral ischemia-reperfusion injury. To determine the role of oxidative stress in mediating proteasome inhibition, ischemia-reperfusion studies were conducted in mice that either overexpressed the antioxidant enzyme glutathione peroxidase [GPX 1(+)], or were devoid of glutathione peroxidase activity (GPX -/-). After ischemia-reperfusion, GPX 1(+) mice displayed decreased infarct size, attenuated neurologic impairment, and reduced levels of proteasome inhibition compared with either GPX -/- or wild type mice. In addition, GPX 1(+) mice displayed lower levels of 4-hydroxynonenal-modified proteasome subunits after ischemia-reperfusion injury. Together, these data indicate that proteasome inhibition occurs during cerebral ischemia-reperfusion injury and is mediated, at least in part, by oxidative stress.

Targeted mutation of the gene for cellular glutathione peroxidase (Gpx1) increases noise-induced hearing loss in mice

Reactive oxygen species (ROS) and oxidative stress have been implicated in cochlear injury following loud noise and ototoxins. Genetic mutations that impair antioxidant defenses would be expected to increase cochlear injury following acute insults and to contribute to cumulative injury that presents as age-related hearing loss. We examined whether genetically based deficiency of cellular glutathione peroxidase, a major antioxidant enzyme, increases noise-induced hearing loss in mice. Two-month-old "knockout" mice with a targeted inactivating mutation of the gene coding for glutathione peroxidase (Gpx1) and wild type controls were exposed to broadband noise for one hour at 110 dB SPL. Auditory brainstem response (ABR) thresholds at test frequencies ranging from 5 to 40 kHz were obtained two and four weeks after exposure to determine the stable permanent component of the hearing loss. Depending on test frequency, (compared with controls) Gpx1 knockout mice showed up to 16 dB higher ABR thresholds prior to noise exposure, and up to 15 dB greater noise-induced hearing loss, compared with normal control. Within the cochlear base, there was also a significant contribution of the knockout to inner and outer hair cell loss, as well as nerve fiber loss. Our results support a link between genetic impairment of antioxidant defenses, vulnerability of the cochlea injury, and cochlear degeneration. Such impairment produces characteristics expected of some mutations associated with age-related hearing loss and offers one possible mechanism for their action.

Red cells from glutathione peroxidase-1-deficient mice have nearly normal defenses against exogenous peroxides

The role of glutathione peroxidase in red cell anti-oxidant defense was examined using erythrocytes from mice with a genetically engineered disruption of the glutathione peroxidase-1 (GSHPx-1) gene. Because GSHPx-1 is the sole glutathione peroxidase in the erythrocyte, all red cell GSH peroxidase activity was eliminated. Oxidation of hemoglobin and membrane lipids, using the cis-parinaric acid assay, was determined during oxidant challenge from cumene hydroperoxide and H(2)O(2). No difference was detected between wild-type red cells and GSHPx-1-deficient cells, even at high H(2)O(2) exposures. Thus, GSHPx-1 appears to play little or no role in the defense of the erythrocyte against exposure to peroxide. Simultaneous exposure to an H(2)O(2) flux and the catalase inhibitor 3-amino-1,2,4-triazole supported this conclusion. Hemoglobin oxidation occurred only when catalase was depleted. Circulating erythrocytes from the GSHPx-1-deficient mice exhibited a slight reduction in membrane thiols, indicating that high exposure to peroxides might occur naturally in the circulation. (Blood. 2000;96:1985-1988)

Chronic brain oxidation in a glutathione peroxidase knockout mouse model results in increased resistance to induced epileptic seizures

Systemic administration of kainic acid (KA) to rodents results in limbic seizures and subsequent neurodegeneration similar to that observed in certain types of human epilepsy, and it is a commonly used animal model for this disease. Oxidative stress has been suggested to play a role in the neuronal injury associated with KA administration. Based on this observation, chronic treatment with antioxidants has been proposed as a possible protective therapy against neuronal damage associated with epileptic seizures. Here we demonstrate by histochemical, electrophysiological, and biochemical means that knockout mice with decreased activity of the protective antioxidant enzyme glutathione peroxidase, which display elevated basal brain oxidative stress levels, are resistant to KA-induced seizure activity and neurodegeneration. This appears to be a result of decreased NMDA receptor function due to oxidation of its NR1 subunit. This suggests that the chronic use of antioxidants as antiepileptic agents to modulate NMDA-dependent seizure-induced neurodegeneration may be detrimental rather than protective and calls into question their use as a therapeutic agent in the treatment of epilepsy.