Australian Defence Force Global Health Engagement through malaria and other vectorborne disease programmes in the Pacific and Southeast Asia.

Global Health Engagement is one method employed by the Australian Defence Force (ADF) in pursuit of its objectives to shape Australia's strategic environment and to deter actions against Australia's interests. Two recent examples of such engagements are malaria mitigation programmes led by the ADF Malaria and Infectious Disease Institute in partnership with the Vietnam People's Army and the Papua New Guinea Defence Force. Both programmes were designed with extensive collaboration with host nation stakeholders, empowered local institutions and governance systems, built the capacity of the host nation with the aim of achieving independence from Australian support and met the strategic policy requirements of all nations involved. Process and outcome measures were built into both programmes, providing partner nations with the necessary assurance that funding was being used effectively. The long-term nature of each programme engendered personal trust between individuals and cultural understanding between military units. Recognising the value of formal education in the design and conduct of such programmes, ADF officers participate as students and instructors in the US Uniformed University of the Health Sciences course in Global Health and Global Health Engagement. Critically, this educational opportunity is afforded to future leaders in all professions related to health, including clinicians, military health planners and commanders. While an essential prerequisite to Global Health Engagement Programmes is their technical viability and validity, the most important key to success in the military context is a widespread understanding of how they achieve desired strategic effects for all involved.

The association between nonrestorative sleep and health-related quality of life in Chinese adults: a cross-sectional study.

PURPOSE: Sleep problems are prevalent among the general population and can cause various health problems, which may lead to decreased quality of life. However, little is known about nonrestorative sleep and its implications. This study aimed to examine the association between nonrestorative sleep and health-related quality of life (HRQL) in Chinese adults. METHODS: Data were collected through a cross-sectional study of 500 adults in Hong Kong (66.4% female, average age of 39 years). The Short-Form-12 Health Survey version 2 (SF-12v2), Nonrestorative Sleep Scale (NRSS), Pittsburgh Sleep Quality Index, ENRICHD Social Support Instrument, Patient Health Questionnaire, Perceived Stress Scale, and Hospital Anxiety and Depression Scale were administered. Objective sleep parameters were based on participants' sleep condition over 1 week, as measured using an ActiGraph GT9X Link. RESULTS: Mean standardized scores for the physical component summary (PCS) and mental component summary (MCS) of the SF-12v2 and the NRSS were 50.33 ± 6.50, 49.00 ± 9.03, and 64.77 ± 12.75, respectively. After adjusting for sociodemographic and lifestyle characteristics, sleep quality, objective sleep parameters, social support, somatic symptoms, stress, anxiety, and depression, NRSS scores were associated with PCS (b = 0.12, 95%CI: 0.06 to 0.18, p < 0.001) and MCS (b = 0.08, 95%CI: 0.02 to 0.15, p = 0.013) scores. Furthermore, associations of NRSS score with PCS as well as MCS scores were stronger in women than in men. CONCLUSION: Nonrestorative sleep is a potentially modifiable risk factor for poor HRQL. Thus, interventions to relieve or decrease nonrestorative sleep could be beneficial for improving HRQL.

Nonrestorative sleep scale: a reliable and valid short form of the traditional Chinese version.

PURPOSE: Previous research has suggested the essential unidimensionality of the 12-item traditional Chinese version of the Nonrestorative Sleep Scale (NRSS). This study aimed to develop a short form of the traditional Chinese version of the NRSS without compromising its reliability and validity. METHODS: Data were collected from 2 cross-sectional studies with identical target groups of adults residing in Hong Kong. An iterative Wald test was used to assess differential item functioning by gender. Based on the generalized partial credit model, we first obtained a shortened version such that further shortening would result in substantial sacrifice of test information and standard error of measurement. Another shortened version was obtained by the optimal test assembly (OTA). The two shortened versions were compared for test information, Cronbach's alpha, and convergent validity. RESULTS: Data from a total of 404 Chinese adults (60.0% female) who had completed the Chinese NRSS were gathered. All items were invariant by gender. A 6-item version was obtained beyond which the test performance substantially deteriorated, and a 9-item version was obtained by OTA. The 9-item version performed better than the 6-item version in test information and convergent validity. It had discrimination and difficulty indices ranging from 0.44 to 2.23 and - 7.58 to 2.13, respectively, and retained 92% of the test information of the original 12-item version. CONCLUSION: The 9-item Chinese NRSS is a reliable and valid tool to measure nonrestorative sleep for epidemiological studies.

Nonrestorative sleep scale: reliable and valid for the Chinese population.

PURPOSE: To conduct a linguistic and psychometric evaluation of a Chinese version of the Nonrestorative Sleep Scale (NRSS). METHODS: The Chinese NRSS was created from a standard forward-backward translation and trialed on 10 Chinese adults. Telephone interviews were then conducted with 100 adults, who completed the Chinese NRSS, the Pittsburgh Sleep Quality Index (PSQI), the Athens Insomnia Scale (AIS), the Center for Epidemiological Studies Depression Scale (CES-D), and the Toronto Hospital Alertness Test (THAT). A household survey was conducted with 20 subjects, followed by a confirmatory factor analysis (CFA), and a bifactor model was developed to evaluate the reliability and validity of the NRSS. RESULTS: The bifactor model had the root mean square error of approximation (RMSEA), standardized root mean square residual (SRMR), and comparative fit index (CFI) of 0.06, 0.06, and 0.97, respectively. Convergent validity was shown from the moderate associations with PSQI (r = - 0.66, P < 0.01), AIS (r = - 0.65, P < 0.01), CES-D (r = - 0.54, P < 0.01), and THAT (r = 0.68, P < 0.01). The coefficient omega (0.92), omega hierarchical (0.81), factor determinacy (0.93), H value (0.91), explained common variance (0.63), and percentage of uncontaminated correlations (0.80) derived from the bifactor CFA supported the essential unidimensionality of NRSS. CONCLUSIONS: The Chinese NRSS is a valid and reliable essential unidimensional tool for the assessment of nonrestorative sleep in the Chinese population.

Assessment of the burden of human African trypanosomiasis by rapid participatory appraisal in three high-risk villages in Urambo District, Northwest Tanzania.

BACKGROUND: The public health and socio-economic burden of Human African Trypanosomiasis (HAT) in East Africa is not well documented. Understanding the epidemiology and impact of HAT in such settings is difficult due to a lack of robust surveillance and reporting systems, restricting evidence-based policy development and contributing to the continued neglect of this disease. OBJECTIVE: To investigate the burden of HAT in Urambo District, Tanzania in order to inform future public health policy. METHODS: A rapid participatory appraisal (RPA) using a combination of qualitative and quantitative methods was conducted, that included key informant interviews, hospital record analysis, and tools adapted from participatory learning and action. RESULTS: Three villages adjacent to Ugala Game Reserve appeared to be the most affected. High levels of under-reporting were noted due to a lack of diagnostic tools at peripheral health care facilities and limited access to specialist services. Community stakeholders perceived the health and socio-economic burden of HAT to be similar to that of malaria. CONCLUSION: The burden of HAT in remote rural communities is difficult to capture through routine surveillance systems alone. The RPA represents an efficient mechanism for engaging communities in public health action for trypanosomiasis control in northwest Tanzania.

Detection improvement for neonatal click evoked otoacoustic emissions by time-frequency filtering.

This study employed a time-frequency filtering technique to improve click evoked otoacoustic emission (CEOAE) detection at lower frequency bands, and hence to reduce the number of referral cases in neonatal OAE screening. Using this approach the detectability of CEOAEs, in terms of lower frequency SNRs and whole wave reproducibility, was significantly improved. Evaluations of screening outcomes demonstrated this method significantly reduced the overall referral rate, by 2.5 percentage points in initial CEOAE hearing screening. This approach may have potential application in OAE technology and in neonatal hearing screening programmes.

Hearing screening for school children: comparison of low-cost, computer-based and conventional audiometry.

BACKGROUND: There is a need to develop affordable but effective audiometric screening equipment, particularly for use in low-income countries. With advances in computer technology, low-cost computer-based audiometer software has been developed. However, the efficacy of computer-based audiometers in hearing screening and diagnostic assessment requires investigation. The purpose of this study was to evaluate the accuracy of a low-cost, computer-based audiometric system in a school-based hearing screening programme. METHODS: Eighty children were screened using the computer-based audiometer and with a conventional pure tone screening audiometer. Overall refer rates, as well as frequency and age effects on the accuracy of the computer-based audiometer, were considered. RESULTS: There was a significant relationship between the low-cost, computer-based audiometer and a conventional pure tone audiometer when a 40 dBHL refer criterion was used in school hearing screening and when test results at 500 Hz were excluded from analysis. However, background noise effects and software limitations in the computer-based system had major adverse effects on screening performance. CONCLUSIONS: The study results and preliminary practical experience with the system suggest that, with further software and hardware improvements, a low-cost, computer-based system may well be feasible for routine school screening in developing countries.

Time-frequency analysis of click-evoked otoacoustic emissions by means of a minimum variance spectral estimation-based method.

This paper proposes a new minimum variance spectral estimation (MVSE)-based time-frequency analysis (TFA) technique for click-evoked otoacoustic emissions (CEOAEs). The MVSE is a popular spectrum analysis method which can yield a high frequency resolution compared to other nonparametric spectral analysis procedures. The conventional MVSE is extended to a TFA method by windowing the observation data to obtain a time-frequency representation for the signal under study. Inspired by the adaptive window selection process in wavelet transform and based on the time-frequency characteristics of CEOAEs, the window size of the windowed MVSE (WMVSE) is given a small value at high frequencies and a large value at low frequencies. The adaptive window size selection yields the proposed frequency-dependent WMVSE (FDWMVSE). The FDWMVSE method integrates the advantages of the adaptive window selection in wavelet transform with the fine frequency resolution of MVSE. Experimental results show that the FDWMVSE can achieve satisfactory time-frequency resolution and reveal meaningful time-frequency features when applied to synthesized and real CEOAEs.

Infant hearing screening: effects of timeline.

OBJECTIVES: Universal infant hearing screening using otoacoustic emission and auditory brain-stem response audiometry is widely administered to attain the goals of early identification of, and intervention for hearing impairment. Concerns regarding screening specificity have, however, been raised. False positives may result from vernix occlusion in the ear canal or transient middle ear effusion, and can result in substantial costs to health care systems. The current study investigates the effects of age and time interval between tests on hearing assessment results. SETTING & PARTICIPANTS: Three hundred and seventeen positive screens from a 2-stage distortion product otoacoustic emission (DPOAE) screening programme in Hong Kong, who subsequently received diagnostic auditory brainstem response (ABR) assessment and monitoring, were investigated. MAIN OUTCOME MEASURES: Differences in diagnostic ABR results were compared among infants of different ages at tests, and with different time lapses after DPOAE screening. The proportion of those having persistent hearing impairment, conductive loss and impairment of moderate degree or above, were also compared. RESULTS: A significantly higher rate of normal ABR thresholds (60%versus 24%) was noted in infants assessed after age 50 days, and in infants diagnostically assessed with a time lapse of over 20 days post-DPOAE screening (65%versus 42%). CONCLUSIONS: Delaying diagnostic ABR assessment may reveal a higher percentage of normal thresholds, and hence probably higher specificity. Time delay may allow for spontaneous resolution of transient outer and middle ear conditions. However, the goals of early identification and intervention, as well as possible parental anxiety with delayed assessment, should also be considered when reviewing infant hearing screening schedules.

Chinese attitudes toward cleft lip and palate: effects of personal contact.

OBJECTIVE: The purpose of this study was to investigate the effect of personal contact on the attitudes of individuals towards persons with cleft lip and palate (CLP) and the possible cultural differences in these attitudes for Chinese respondents living in Hong Kong. DESIGN: Chinese parent, teacher, and employer groups were administered a cleft lip and palate attitudinal questionnaire and the Scale of Attitudes Toward Disabled Persons inventory. SUBJECTS: Thirty-nine parents of children with CLP, 27 teachers of children with CLP, and 37 employers with no previous contact with individuals with CLP participated in the study. RESULTS: The results showed significant intergroup differences on several items involving beliefs concerning emotional health, social development, and employment-related barriers for individuals with CLP, and whether such individuals should seek nonmedical help to treat speech problems. Employers showed a comparatively less favorable attitude to persons with CLP than the two other groups. CONCLUSION: Parent, teacher, and employer groups in the Chinese community studied showed differences in their attitudes towards individuals with CLP. The findings suggest the need for further community health education to help develop more positive attitudes towards disabled persons in general, as well as programs targeted at reducing negative stereotyping of adults and children with CLP.

Neonatal hearing screening: evaluation of tone-burst and click-evoked otoacoustic emission test criteria.

OBJECTIVE: Click-evoked otoacoustic emissions (CEOAEs) are widely used in universal neonatal hearing screening programs. A common finding in many such programs is a relatively high false-positive rate. This is often due to infant physiological noise adversely affecting the emission recording, leading to a "refer" screening outcome. In an attempt to reduce false-positive screening outcomes related to the effects of noise on otoacoustic emission response detection, tone-burst-evoked otoacoustic emissions (TBOAEs) were included in a neonatal hearing screening program because TBOAEs may elicit a greater signal-to-noise ratio than CEOAEs. The research project compared the pass/refer rate for a CEOAE-based test using established pass/refer criteria with the pass/refer rate for screening criteria that were based on TBOAE results alone or on combined CEOAE and TEOAE results. DESIGN: Neonates were recruited at the Hong Kong Adventist Hospital, and both CEOAEs and TBOAEs were performed. Six passing criteria were used in this study, based on CEOAEs only; CEOAEs plus 1 kHz TBOAEs; CEOAEs plus 2 kHz TBOAEs; CEOAEs plus 3 kHz TBOAEs; CEOAEs plus 1, 2, and 3 kHz TBOAEs; and TBOAEs only. RESULTS: Data from 298 neonates (546 ears) were obtained. Criteria set 1, using CEOAEs only, demonstrated a pass rate of 79.1%, and 114 ears were referred. Criteria set 2, using CEOAEs together with TBOAEs recorded at 1 kHz, passed 39 more ears than Protocol 1, and the pass rate was 86.3%. Hence, the overall referral rate for total number of screened ears decreased by 7.2 percentage points. Criteria set 3, using CEOAEs together with TBOAEs recorded at 2 kHz, and Criteria set 4, using CEOAEs in conjunction with TBOAEs recorded at 3 kHz, gave pass rates similar to Criteria set 1. Criteria set 5, using TBOAE information at frequencies where CEOAEs were not rated as "pass," raised the pass rate from 79.1 to 87.6%, reducing the overall referral rate by 8.5 percentage points. Criteria set 6, in which neonates were screened with TBOAEs recorded at 1, 2, and 3 kHz, gave a pass rate of 78.4%, similar to results for the CEOAE-only procedure. CONCLUSIONS: Both Criteria sets 2 and 5, which combined CEOAE and TBOAE recordings, gave significantly higher pass rates than Criteria sets 1, 3, 4, and 6. The results suggest that the introduction of combined CEOAE and TBOAE protocols may assist in the reduction of refer outcomes, and hence the false-positive rates, of neonatal hearing screening programs.

Effectiveness of an affordable hearing aid with elderly persons.

PURPOSE: his study evaluated the effectiveness of a recently developed, low-cost 'over-the-counter' style hearing aid with elderly people, who had mild to moderate mixed or sensorineural hearing losses. Two aspects were focused upon, objective change in the participants' aided hearing measures and the self-reported performance and benefit obtained from the hearing aid. METHOD: The hearing aids were trialed by 19 elderly persons over a 3-month period. Aided hearing thresholds and real-ear insertion gain measures were obtained from participants, three questionnaires (the Client-Oriented Scale of Improvement [COSI], the International Outcome Inventory for Hearing Aids [IOI-HA] and the Profile of Hearing Aid Performance--Chinese version [PHAP-C]) were completed, and an open-ended interview was conducted. RESULTS: Objective tests noted that the trial hearing aid was able to provide appropriate amplification for the elderly participants in this study. The device was rated by the majority of participants as providing benefit, with 16 of the participants (84%) using their hearing aid from at least 1 to over 8 h each day and with all participants considering the low-cost instrument 'worth the trouble' of wearing. Participant ratings of benefit with the IOI-HA were comparable with those obtained in a normative study in which subjects used more expensive conventional hearing aids. Using the COSI questionnaire, participants typically concluded that their hearing improvement with the study device was 'slightly better' to 'better' than without amplification. The PHAP-C questionnaire results indicated that, while wearing their hearing aids, participants experienced difficulties only infrequently in most everyday listening situations. Comments made during open-ended interviews were equally positive and negative, with most negative comments focused on difficulties with either acoustic feedback or background noise annoyance while wearing the hearing instrument.CONCLUSION. Affordable, over-the-counter hearing devices provide a potential opportunity for greater numbers of persons with hearing loss to access amplification and benefit from improved communicative abilities. Further investigation and further development of these instruments is warranted, to provide enhanced rehabilitation outcomes for elderly persons with hearing impairment.

Audiometric configurations of hearing impaired children in Hong Kong: implications for amplification.

PURPOSE: Children with hearing loss who require special school placement may have a wide range of audiometric configurations. Since such children will vary in auditory status their amplification requirements may also be diverse. This study examined the audiological records of 231 children attending four schools for hearing impaired children in Hong Kong to gain an understanding of common audiometric patterns found in the school children and their auditory rehabilitation needs. METHOD: Data on the children's aetiology of hearing loss, hearing status, tympanometric findings and the electroacoustic characteristics of their hearing aids were obtained. For 424 children's ears considered having essentially sensorineural hearing loss, k-means cluster analysis methods were used to categorize audiometric configuration groups. RESULTS: Cluster analysis that indicated that five distinct audiometric configurations could be found among the school children. Different clusters contained children who had differing amplification needs. The study analysed a number of parameters to check fitting outcomes, including average prescribed gain, frequency-specific measured versus prescribed gain, prescribed frequency response, measured versus prescribed frequency response and the predicted aided thresholds for the children. CONCLUSION: The amplification needs associated with these five configurations, including recommended prescription gain, maximum power output and possible signal processing strategies, were considered. The clustering algorithm approach proved useful as a means of grouping distinctive audiometric profiles.

Role of opioid delta1 receptors, mitochondrial K(ATP) channels, and protein kinase C during cardiocyte apoptosis.

Opioids attenuate cardiac injury after ischemia and reperfusion. We wanted to determine whether the protection of opioids is mediated by blocking cardiocyte apoptosis, and if so, to describe the role of opioid delta1 receptors and protein kinase C (PKC) in this effect. Chick embryonic cardiomyocytes were subjected to 12 h of simulated ischemia and then 12 h of re-oxygenation, which resulted in 54+/-3% (n=6) of cell apoptosis (n=6) as measured by flow cytometry. This result was consistent with DNA laddering and TUNEL assay. Preconditioning, elicited with three cycles of 1 min of simulated ischemia separated by 5 min of reoxygenation before prolonged simulated ischemia, reduced apoptosis (36+/-4%, n=6*). Pretreatment with BNTX (0.1 micromol/l), a selective opioid delta1 receptor blocker, abolished the effects of preconditioning (57+/-5%, n=6). The selective opioid delta receptor agonist BW373U86 (20 pmol/l) also attenuated apoptosis (39+/-3%, n=6* v control). These effects were abolished by 5-hydroxydecanoate (100 microm), a selective mitochondrial K(ATP) channel blocker (50+/-5%, n=6) and by Go-6976 (0.1 micromol/l), a specific PKC inhibitor. Both preconditioning and BW373U86 activated the PKC delta isoform of particulate fraction before simulated ischemia without effect on total and cytosolic fractions. Stimulation of opioid delta1 receptors activates mitochondrial K(ATP) channels and the PKC delta isoform in cultured ventricular myocytes. This is one important signal transduction pathway through which ischemic preconditioning blocks apoptosis and preserves cardiac function.

Screening for auditory neuropathy in a school for hearing impaired children.

OBJECTIVE: Hearing loss in children may be due to a wide variety of pathologies. Recently, use of otoacoustic emission technology has led to identification of auditory neuropathy as a distinct hearing disorder. Children with auditory neuropathy require audiological and educational management that may differ from that required by other hearing impaired students. For this reason, screening for auditory neuropathy may be appropriate for children attending schools for the hearing impaired. The study investigated the utility of using otoacoustic emission measures for school screening of hearing impaired children. METHODS: In this study, 81 children aged 6-12 years who attended one school for the deaf were screened for indications of auditory neuropathy. Children found to have consistent otoacoustic emissions were given a full diagnostic audiological test battery. RESULTS: Two children had transient otoacoustic emission results indicating normal outer hair cell function in one or both ears. A follow-up diagnostic assessment for the two positive cases was strongly suggestive of auditory neuropathy. CONCLUSIONS: There is a need for routine auditory neuropathy screening at schools for hearing impaired children.

Effects of speech babble on transient evoked otoacoustic emissions in normal-hearing adults.

The results of transient evoked otoacoustic emissions (TEOAEs) have been found to be adversely affected by noise. However, there are few investigations into the specific effect of background noise on TEOAEs. The purpose of the present study was to determine the effects of increasing levels of speech babble and the recording method on TEOAEs using the ILO88 Otodynamics instrumentation. Subjects were 30 normal-hearing adults (15 males and 15 females), aged between 18 and 32 years. TEOAE recordings were obtained from both ears of each subject under five different levels of speech babble delivered via a loudspeaker in sound field using both the default and Quickscreen methods of data collection. The results indicated that both the whole-wave reproducibility (WWR) and mean signal-to-noise ratio (MSNR), averaged across frequencies from about 2 to 4 kHz, decreased with increasing speech babble levels. The results also showed that the Quickscreen mode was less susceptible to noise than the default mode. The pass percentage, using either WWR > or = 50 percent or an MSNR > or = 3 dB as a pass criterion, also decreased with increasing speech babble levels. Furthermore, the findings indicated that the use of the WWR pass criterion resulted in a high failure rate under high levels of speech babble. In contrast, the MSNR pass criterion was robust to speech babble levels of up to 70 dBA in the Quickscreen mode and 65 dBA in the default setting. The clinical implications of these findings, as applied to non-sound-treated environments, are discussed.

Signal transduction of opioid-induced cardioprotection in ischemia-reperfusion.

BACKGROUND: Morphine reduces myocardial ischemia-reperfusion injury in vivo and in vitro. The authors tried to determine the role of opioid delta1 receptors, oxygen radicals, and adenosine triphosphate-sensitive potassium (KATP) channels in mediating this effect. METHODS: Chick cardiomyocytes were studied in a flow-through chamber while pH, flow rate, oxygen, and carbon dioxide tension were controlled. Cell viability was quantified by nuclear stain propidium iodide, and oxygen radicals were quantified using molecular probe 2',7'-dichlorofluorescin diacetate. RESULTS: Morphine (1 microM) or the selective delta-opioid receptor agonist BW373U86 (10 pM) given for 10 min before 1 h of ischemia and 3 h of reoxygenation reduced cell death (31 +/- 5%, n = 6, and 28 +/- 5%, n = 6 [P < 0.05], respectively, 53 +/- 6%, n = 6, in controls) and generated oxygen radicals before ischemia (724 +/- 53, n = 8, and 742 +/- 75, n = 8 [P < 0.05], respectively, vs. 384 +/- 42, n = 6, in controls, arbitrary units). The protection of morphine was abolished by naloxone, or the selective delta1-opioid receptor antagonist 7-benzylidenenaltrexone. Reduction in cell death and increase in oxygen radicals with BW373U86 were blocked by the selective mitochondrial KATP channel antagonist 5-hydroxydecanoate or diethyldithiocarbamic acid (1,000 microM), which inhibited conversion of O2- to H2O2. The increase in oxygen radicals was abolished by the mitochondrial electron transport inhibitor myxothiazoL Reduction in cell death was associated with attenuated oxidant stress at reperfusion. CONCLUSION: Stimulation of delta1-opioid receptors generates oxygen radicals via mitochondrial KATP channels. This signaling pathway attenuates oxidant stress and cell death in cardiomyocytes.

Role of nitric oxide and protein kinase C in ACh-induced cardioprotection.

We examined the roles of nitric oxide and protein kinase C (PKC) in ACh-produced protection of cultured cardiomyocytes during simulated ischemia and reoxygenation. Cell viability was quantified using propidium iodide in chick embryonic ventricular myocytes. O(2) radicals were quantified using 2',7'-dichlorofluorescin diacetate. After a 10-min infusion of ACh (0.5 or 1 mM) and a 10-min drug-free period, we simulated ischemia for 1 h and reoxygenation for 3 h. ACh reduced cardiocyte death [32 +/- 4%; n = 6 and 23 +/- 4%; n = 7 (P < 0.05)] and attenuated oxidant stress during ischemia and reoxygenation in a concentration-dependent manner compared with controls (47 +/- 4%; n = 8; P < 0.05). The increase in O(2) radicals before simulated ischemia [357 +/- 49; n = 4 and 528 +/- 52; n = 8 vs. 211 +/- 34; n = 8; P < 0.05 (arbitrary units)] was abolished by the specific nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and was markedly attenuated by N(G)-monomethyl-L-arginine (L-NMMA). L-NAME or L-NMMA blocked the protective effects of ACh, which selectively increased PKC-epsilon isoform activity in the particulate fraction. The PKC inhibitor Gö-6976 had no effect on O(2) radical production before simulated ischemia but it abolished the protection; therefore nitric oxide is a large component of ACh-generated O(2) radicals. Nitric oxide and O(2) radicals activate the PKC-epsilon isoform by which ACh protects against injury.

Preconditioning attenuates apoptosis and necrosis: role of protein kinase C epsilon and -delta isoforms.

Preconditioning reduces cardiomyocyte necrosis in vivo and in vitro, but it is unknown whether preconditioning blocks apoptosis. We wanted to compare the effects of preconditioning on necrosis and apoptosis in cardiomyocytes. Necrosis was detected with propidium iodide, and apoptosis was quantified by three complementary techniques: flow cytometry, TdT-mediated dUTP nick-end labeling assay, and DNA-laddering electrophoresis. Apoptosis increased with simulated ischemia time (6 h, 19 +/- 1%; 12 h, 27 +/- 2%; 18 h, 40 +/- 4%; 24 h, 54 +/- 4%; and 36 h, 83 +/- 4%; n = 6 for each group). Simulated ischemia and reoxygenation contributed equally to apoptosis (12-h ischemia, 27 +/- 2%, n = 6; 12-h ischemia and 12-h reoxygenation, 51 +/- 4%, n = 6; and 24-h ischemia, 54 +/- 5%, n = 8). Necrosis occurred primarily during reoxygenation; none was detected during simulated ischemia. Preconditioning with 10 min of simulated ischemia reduced necrosis (18 +/- 6%, n = 8) but had no effect on apoptosis. However, three 1-min cycles of simulated ischemia separated by 5 min of reoxygenation reduced necrosis and apoptosis similarly. The protein kinase C (PKC) inhibitors Go6976 (0.1 microM) or chelerythrene (4 microM) abolished the effect of preconditioning. Preconditioning selectively activated PKC epsilon but had no effect on PKC delta and on total PKC enzyme activity. Preconditioning protected against necrosis and apoptosis, but the preconditioning ischemia required for blocking apoptosis was less than that for reducing necrosis. Activation of PKC epsilon isoform is important in mediating the protection.