High uptake of menstrual health information, products and analgesics within an integrated sexual reproductive health service for young people in Zimbabwe

BACKGROUND

Despite being integral to women's well-being, achieving good menstrual health (MH) remains a challenge. This study examined MH services uptake (including information, analgesics, and a choice of MH products - the menstrual cup and reusable pads) and sustained use of MH products within an integrated sexual and reproductive health intervention for young people in Zimbabwe.

METHODS

This mixed-methods study was nested within a cluster randomised trial of integrated sexual and reproductive health services (CHIEDZA) for youth in three provinces (Harare, Mashonaland East, and Bulawayo). The study collected qualitative and quantitative data from 27,725 female clients aged 16-24 years, who accessed CHIEDZA from April 2019 - March 2022. Using a biometric (fingerprint recognition) identification system, known as SIMPRINTS, uptake of MH information, products, and analgesics and other services was tracked for each client. Descriptive statistics and logistic regression were used to investigate MH service uptake and product choice and use over time, and the factors associated with these outcomes. Thematic analysis of focus group discussions and interviews were used to further explore providers' and participants' experiences of the MH service and CHIEDZA intervention.

RESULTS

Overall, 36,991 clients accessed CHIEDZA of whom 27,725 (75%) were female. Almost all (n = 26,448; 95.4%) took up the MH service at least once: 25433 took up an MH product with the majority (23,346; 92.8%) choosing reusable pads. The uptake of cups varied across province with Bulawayo province having the highest uptake (13.4%). Clients aged 20-24 years old were more likely to choose cups than reusable pads compared with those aged 16-19 years (9.4% vs 6.0%; p < 0.001). Over the implementation period, 300/1819 (16.5%) of clients swapped from the menstrual cup to reusable pads and 83/23346 (0.4%) swapped from reusable pads to the menstrual cup. Provision of the MH service encouraged uptake of other important SRH services. Qualitative findings highlighted the provision of free integrated SRH and MH services that included a choice of MH products and analgesics in a youth-friendly environment were key to high uptake and overall female engagement with SRH services.

CONCLUSIONS

High uptake demonstrates how the MH service provided much needed access to MH products and information. Integration of MH within an SRH intervention proved central to young women accessing other SRH services.

Diagnostic accuracy of a three-gene Mycobacterium tuberculosis host response cartridge using fingerstick blood for childhood tuberculosis: a multicentre prospective study in low-income and middle-income countries

BACKGROUND

Childhood tuberculosis remains a major cause of morbidity and mortality in part due to missed diagnosis. Diagnostic methods with enhanced sensitivity using easy-to-obtain specimens are needed. We aimed to assess the diagnostic accuracy of the Cepheid Mycobacterium tuberculosis Host Response prototype cartridge (MTB-HR), a candidate test measuring a three-gene transcriptomic signature from fingerstick blood, in children with presumptive tuberculosis disease.

METHODS

RaPaed-TB was a prospective diagnostic accuracy study conducted at four sites in African countries (Malawi, Mozambique, South Africa, and Tanzania) and one site in India. Children younger than 15 years with presumptive pulmonary or extrapulmonary tuberculosis were enrolled between Jan 21, 2019, and June 30, 2021. MTB-HR was performed at baseline and at 1 month in all children and was repeated at 3 months and 6 months in children on tuberculosis treatment. Accuracy was compared with tuberculosis status based on standardised microbiological, radiological, and clinical data.

FINDINGS

5313 potentially eligible children were screened, of whom 975 were eligible. 784 children had MTB-HR test results, of whom 639 had a diagnostic classification and were included in the analysis. MTB-HR differentiated children with culture-confirmed tuberculosis from those with unlikely tuberculosis with a sensitivity of 59·8% (95% CI 50·8-68·4). Using any microbiological confirmation (culture, Xpert MTB/RIF Ultra, or both), sensitivity was 41·6% (34·7-48·7), and using a composite clinical reference standard, sensitivity was 29·6% (25·4-34·2). Specificity for all three reference standards was 90·3% (95% CI 85·5-94·0). Performance was similar in different age groups and by malnutrition status. Among children living with HIV, accuracy against the strict reference standard tended to be lower (sensitivity 50·0%, 15·7-84·3) compared with those without HIV (61·0%, 51·6-69·9), although the difference did not reach statistical significance. Combining baseline MTB-HR result with one Ultra result identified 71·2% of children with microbiologically confirmed tuberculosis.

INTERPRETATION

MTB-HR showed promising diagnostic accuracy for culture-confirmed tuberculosis in this large, geographically diverse, paediatric cohort and hard-to-diagnose subgroups.

FUNDING

European and Developing Countries Clinical Trials Partnership, UK Medical Research Council, Swedish International Development Cooperation Agency, Bundesministerium für Bildung und Forschung; German Center for Infection Research (DZIF).

Development and Implementation of Digital Diagnostic Algorithms for Neonatal Units in Zimbabwe and Malawi: Development and Usability Study

BACKGROUND

Despite an increase in hospital-based deliveries, neonatal mortality remains high in low-resource settings. Due to limited laboratory diagnostics, there is significant reliance on clinical findings to inform diagnoses. Accurate, evidence-based identification and management of neonatal conditions could improve outcomes by standardizing care. This could be achieved through digital clinical decision support (CDS) tools. Neotree is a digital, quality improvement platform that incorporates CDS, aiming to improve neonatal care in low-resource health care facilities. Before this study, first-phase CDS development included developing and implementing neonatal resuscitation algorithms, creating initial versions of CDS to address a range of neonatal conditions, and a Delphi study to review key algorithms.

OBJECTIVE

This second-phase study aims to codevelop and implement neonatal digital CDS algorithms in Malawi and Zimbabwe.

METHODS

Overall, 11 diagnosis-specific web-based workshops with Zimbabwean, Malawian, and UK neonatal experts were conducted (August 2021 to April 2022) encompassing the following: (1) review of available evidence, (2) review of country-specific guidelines (Essential Medicines List and Standard Treatment Guidelinesfor Zimbabwe and Care of the Infant and Newborn, Malawi), and (3) identification of uncertainties within the literature for future studies. After agreement of clinical content, the algorithms were programmed into a test script, tested with the respective hospital's health care professionals (HCPs), and refined according to their feedback. Once finalized, the algorithms were programmed into the Neotree software and implemented at the tertiary-level implementation sites: Sally Mugabe Central Hospital in Zimbabwe and Kamuzu Central Hospital in Malawi, in December 2021 and May 2022, respectively. In Zimbabwe, usability was evaluated through 2 usability workshops and usability questionnaires: Post-Study System Usability Questionnaire (PSSUQ) and System Usability Scale (SUS).

RESULTS

Overall, 11 evidence-based diagnostic and management algorithms were tailored to local resource availability. These refined algorithms were then integrated into Neotree. Where national management guidelines differed, country-specific guidelines were created. In total, 9 HCPs attended the usability workshops and completed the SUS, among whom 8 (89%) completed the PSSUQ. Both usability scores (SUS mean score 75.8 out of 100 [higher score is better]; PSSUQ overall score 2.28 out of 7 [lower score is better]) demonstrated high usability of the CDS function but highlighted issues around technical complexity, which continue to be addressed iteratively.

CONCLUSIONS

This study describes the successful development and implementation of the only known neonatal CDS system, incorporated within a bedside data capture system with the ability to deliver up-to-date management guidelines, tailored to local resource availability. This study highlighted the importance of collaborative participatory design. Further implementation evaluation is planned to guide and inform the development of health system and program strategies to support newborn HCPs, with the ultimate goal of reducing preventable neonatal morbidity and mortality in low-resource settings.

Evaluation of a comprehensive health check offered to frontline health workers in Zimbabwe

Health workers are essential for a functioning healthcare system, and their own health is often not addressed. During the COVID-19 pandemic health workers were at high risk of SARS-CoV-2 infection whilst coping with increased healthcare demand. Here we report the development, implementation, and uptake of an integrated health check combining SARS-CoV-2 testing with screening for other communicable and non-communicable diseases for health workers in Zimbabwe during the COVID-19 pandemic. Health checks were offered to health workers in public and private health facilities from July 2020 to June 2022. Data on the number of health workers accessing the service and yield of screening was collected. Workshops and in-depth interviews were conducted to explore the perceptions and experiences of clients and service providers. 6598 health workers across 48 health facilities accessed the service. Among those reached, 5215 (79%) were women, the median age was 37 (IQR: 29-44) years and the largest proportion were nurses (n = 2092, 32%). 149 (2.3%) healthcare workers tested positive for SARS-CoV-2. Uptake of screening services was almost 100% for all screened conditions except HIV. The most common conditions detected through screening were elevated blood pressure (n = 1249; 19%), elevated HbA1c (n = 428; 7.7%) and common mental disorder (n = 645; 9.8%). Process evaluation showed high acceptability of the service. Key enablers for health workers accessing the service included free and comprehensive service provision, and availability of reliable point-of-care screening methods. Implementation of a comprehensive health check for health workers was feasible, acceptable, and effective, even during a pandemic. Conventional occupational health programmes focus on infectious diseases. In a society where even health workers cannot afford health care, free comprehensive occupational health services may address unmet needs in prevention, diagnosis, and treatment for chronic non-communicable conditions.

Development and Pilot Implementation of Neotree, a Digital Quality Improvement Tool Designed to Improve Newborn Care and Survival in 3 Hospitals in Malawi and Zimbabwe: Cost Analysis Study

Background

Two-thirds of the 2.4 million newborn deaths that occurred in 2020 within the first 28 days of life might have been avoided by implementing existing low-cost evidence-based interventions for all sick and small newborns. An open-source digital quality improvement tool (Neotree) combining data capture with education and clinical decision support is a promising solution for this implementation gap.

Objective

We present results from a cost analysis of a pilot implementation of Neotree in 3 hospitals in Malawi and Zimbabwe.

Methods

We combined activity-based costing and expenditure approaches to estimate the development and implementation cost of a Neotree pilot in 1 hospital in Malawi, Kamuzu Central Hospital (KCH), and 2 hospitals in Zimbabwe, Sally Mugabe Central Hospital (SMCH) and Chinhoyi Provincial Hospital (CPH). We estimated the costs from a provider perspective over 12 months. Data were collected through expenditure reports, monthly staff time-use surveys, and project staff interviews. Sensitivity and scenario analyses were conducted to assess the impact of uncertainties on the results or estimate potential costs at scale. A pilot time-motion survey was conducted at KCH and a comparable hospital where Neotree was not implemented.

Results

Total cost of pilot implementation of Neotree at KCH, SMCH, and CPH was US $37,748, US $52,331, and US $41,764, respectively. Average monthly cost per admitted child was US $15, US $15, and US $58, respectively. Staff costs were the main cost component (average 73% of total costs, ranging from 63% to 79%). The results from the sensitivity analysis showed that uncertainty around the number of admissions had a significant impact on the costs in all hospitals. In Malawi, replacing monthly web hosting with a server also had a significant impact on the costs. Under routine (nonresearch) conditions and at scale, total costs are estimated to fall substantially, up to 76%, reducing cost per admitted child to as low as US $5 in KCH, US $4 in SMCH, and US $14 in CPH. Median time to admit a baby was 27 (IQR 20-40) minutes using Neotree (n=250) compared to 26 (IQR 21-30) minutes using paper-based systems (n=34), and the median time to discharge a baby was 9 (IQR 7-13) minutes for Neotree (n=246) compared to 3 (IQR 2-4) minutes for paper-based systems (n=50).

Conclusions

Neotree is a time- and cost-efficient tool, comparable with the results from limited similar mHealth decision-support tools in low- and middle-income countries. Implementation costs of Neotree varied substantially between the hospitals, mainly due to hospital size. The implementation costs could be substantially reduced at scale due to economies of scale because of integration to the health systems and reductions in cost items such as staff and overhead. More studies assessing the impact and cost-effectiveness of large-scale mHealth decision-support tools are needed.

Exploring COVID-19 vaccine uptake among healthcare workers in Zimbabwe: A mixed methods study

With COVID-19 no longer categorized as a public health emergency of international concern, vaccination strategies and priority groups for vaccination have evolved. Africa Centres for Diseases Prevention and Control proposed the '100-100-70%' strategy which aims to vaccinate all healthcare workers, all vulnerable groups, and 70% of the general population. Understanding whether healthcare workers were reached during previous vaccination campaigns and what can be done to address concerns, anxieties, and other influences on vaccine uptake, will be important to optimally plan how to achieve these ambitious targets. In this mixed-methods study, between June 2021 and July 2022 a quantitative survey was conducted with healthcare workers accessing a comprehensive health check in Zimbabwe to determine whether and, if so, when they had received a COVID-19 vaccine. Healthcare workers were categorized as those who had received the vaccine 'early' (before 30.06.2021) and those who had received it 'late' (after 30.06.2021). In addition, 17 in-depth interviews were conducted to understand perceptions and beliefs about COVID-19 vaccines. Of the 3,086 healthcare workers employed at 43 facilities who participated in the study, 2,986 (97%, 95% CI [92%-100%]) reported that they had received at least one vaccine dose. Geographical location, older age, higher educational attainment and having a chronic condition was associated with receiving the vaccine early. Qualitatively, (mis)information, infection risk perception, quasi-mandatory vaccination requirements, and legitimate concerns such as safety and efficacy influenced vaccine uptake. Meeting the proposed 100-100-70 target entails continued emphasis on strong communication while engaging meaningfully with healthcare workers' concerns. Mandatory vaccination may undermine trust and should not be a substitute for sustained engagement.

Feasibility and Usability of Mobile Technology to Assist HIV Self-Testing in Youth in Zimbabwe: A Mixed-Methods Study

PURPOSE

Mobile technology is increasingly being used to widen access to and support the delivery of public health interventions. Human immunodeficiency viruses (HIV) self-testing (HIVST) enables individuals to have autonomy. We evaluated the feasibility of a novel application called ITHAKA to support HIVST among youth aged 16-24 years in Zimbabwe.

METHODS

This study was nested within a trial of community-based delivery of integrated HIV and sexual and reproductive health services called CHIEDZA. Youth accessing CHIEDZA were offered provider-delivered HIV testing or HIVST supported by ITHAKA, either on a tablet on-site at a community centre or on their mobile phone off-site. ITHAKA incorporated pre and post-test counselling, and instructions for conducting the test and the appropriate actions to take depending on test result, including reporting HIV test results to health providers. The outcome was completion of the testing journey. Semistructured interviews with CHIEDZA providers explored the perceptions of and experiences with the application.

RESULTS

Between April and September 2019, of the 2,181 youth who accepted HIV testing in CHIEDZA, 128 (5.8%) initiated HIVST (the remainder opting for provider-delivered testing) using ITHAKA. Nearly all who performed HIVST on-site (108/109 (99.1%)) compared to only 9/19 (47.4%) who tested off-site completed their testing journey. Low digital literacy, lack of agency, erratic network coverage, lack of dedicated phone ownership, the limited functionality of smartphones challenged implementation of ITHAKA.

DISCUSSION

Digitally supported HIVST had low uptake among youth. The feasibility and usability of digital interventions should be carefully assessed before implementation, paying careful attention to digital literacy, network availability, and access to devices.

Exploring COVID-19 vaccine uptake among healthcare workers in Zimbabwe: A mixed methods study

With COVID-19 no longer categorized as a public health emergency of international concern, vaccination strategies and priority groups for vaccination have evolved. Africa Centers for Diseases Prevention and Control proposed the '100-100-70%' strategy which aims to vaccinate all healthcare workers, all vulnerable groups, and 70% of the general population. Understanding whether healthcare workers were reached during previous vaccination campaigns and what can be done to address concerns, anxieties, and other influences on vaccine uptake, will be important to optimally plan how to achieve these ambitious targets. In this mixed-methods study, between June 2021 and July 2022 a quantitative survey was conducted with healthcare workers accessing a comprehensive health check in Zimbabwe to determine whether and, if so, when they had received a COVID-19 vaccine. Healthcare workers were categorized as those who had received the vaccine 'early' (before 30.06.2021) and those who had received it 'late' (after 30.06.2021). In addition, 17 in-depth interviews were conducted to understand perceptions and beliefs about COVID-19 vaccines. Of the 2905 healthcare workers employed at 37 facilities who participated in the study, 2818 (97%, 95% CI [92%-102%]) reported that they had received at least one vaccine dose. Geographical location, older age, higher educational attainment and having a chronic condition was associated with receiving the vaccine early. Qualitatively, (mis)information, infection risk perception, quasi-mandatory vaccination requirements, and legitimate concerns such as safety and efficacy influenced vaccine uptake. Meeting the proposed 100-100-70 target entails continued emphasis on strong communication while engaging meaningfully with healthcare workers' concerns. Mandatory vaccination may undermine trust and should not be a substitute for sustained engagement.

Addressing sociodemographic disparities in COVID-19 vaccine uptake among youth in Zimbabwe

INTRODUCTION

COVID-19 vaccine acceptance research has mostly originated from high-income countries and reasons why youth may not get vaccinated may differ in low-income settings. Understanding vaccination coverage across different population groups and the sociocultural influences in healthcare delivery is important to inform targeted vaccination campaigns.

METHODS

A population-based survey was conducted in 24 communities across three provinces (Harare, Bulawayo and Mashonaland East) in Zimbabwe between October 2021 and June 2022. Youth aged 18-24 years were randomly selected using multistage sampling. Sociodemographic characteristics, COVID-19 vaccination uptake and reasons for non-uptake were collected, and odds of vaccination was investigated using logistic regression.

RESULTS

17 682 youth were recruited in the survey (n=10 742, 60.8% female). The median age of participants was 20 (IQR: 19-22) years. Almost two thirds (n=10 652, 60.2%) reported receiving at least one dose of COVID-19 vaccine. A higher proportion of men than women had been vaccinated (68.9% vs 54.7%), and vaccination prevalence increased with age (<19 years: 57.5%, 20-22: 61.5%, >23: 62.2%). Lack of time to get vaccinated, belief that the vaccine was unsafe and anxiety about side effects (particularly infertility) were the main reasons for not getting vaccinated. Factors associated with vaccination were male sex (OR=1.69, 95% CI 1.58 to 1.80), increasing age (>22 years: OR=1.12, 95% CI 1.04 to 1.21), education level (postsecondary: OR=4.34, 95% CI 3.27 to 5.76) and socioeconomic status (least poor: OR=1.32, 95% CI 1.20 to 1.47).

CONCLUSION

This study found vaccine inequity across age, sex, educational attainment and socioeconomic status among youth. Strategies should address these inequities by understanding concerns and tailoring vaccine campaigns to specific groups.

High uptake of menstrual health information, products and analgesics within an integrated sexual reproductive health service for young people in Zimbabwe

Background

Achieving good menstrual health (MH), integral to women's well-being, remains a challenge. This study examined MH services uptake (including information, analgesics, and a choice of MH products - the menstrual cup and reusable pads) and sustained use of MH products within an integrated sexual and reproductive health intervention for young people in Zimbabwe.

Methods

This study was embedded within a cluster randomised trial of integrated sexual and reproductive health services (CHIEDZA) in three provinces (Harare, Mashonaland East, and Bulawayo). The study collected qualitative and quantitative data from female clients aged 16-24 years, who accessed CHIEDZA from April 2019 - March 2022. Uptake of MH information, products, and analgesics and other services was tracked for each client. Descriptive statistics and logistic regression were used to investigate MH service uptake and product choice and use over time, and the factors associated with these outcomes. Thematic analysis of focus group discussions and interviews were used to further explore providers' and participants' experiences of the MH service and CHIEDZA intervention.

Results

Overall, 36991 clients accessed CHIEDZA of whom 27725 (75%) were female. Almost all (n = 26448; 95.4%) took up the MH service at least once: 25433 took up an MH product with the majority (23346; 92.8%) choosing reusable pads. The uptake of cups varied across province with Bulawayo province having the highest uptake (13.4%). Clients aged 20-24 years old were more likely to choose cups than reusable pads compared with those aged 16-19 years (9.4% vs 6.0%; p < 0.001). Over the implementation period, 300/1819 (16.5%) of clients swapped from the menstrual cup to reusable pads and 83/23346 (0.4%) swapped from reusable pads to the menstrual cup. Provision of the MH service encouraged uptake of other important SRH services. Qualitative findings highlighted the provision of free integrated SRH and MH services that included a choice of MH products and analgesics in a youth-friendly environment were key to high uptake and overall female engagement with SRH services.

Conclusions

High uptake demonstrates how the MH service provided much needed access to MH products and information. Integration of MH within an SRH intervention proved central to young women accessing other SRH services.

Acceptability of self-collected vaginal swabs for sexually transmitted infection testing among youth in a community-based setting in Zimbabwe

BACKGROUND

Youth are a high-risk group for sexually transmitted infections (STIs). To increase access to STI testing, convenient approaches for sampling and testing are needed. We assessed the acceptability of self-collected vaginal swabs (SCVS) for STI testing among young women (16-24 years) attending a community-based sexual and reproductive health service in Zimbabwe.

METHODS

A SCVS was used for point-of-care testing for Trichomonas vaginalis and a urine sample for testing for Chlamydia trachomatis and Neisseria gonorrhoeae. A questionnaire was administered to investigate the acceptability of SCVS versus self-collected urine samples. In-depth interviews (IDIs) explored the experience of SCVS and reasons for sample collection preference. Qualitative analysis was predominantly deductive.

RESULTS

We recruited 129 women who took up STI testing (median age 20 years, IQR 18-22 years) and conducted 12 IDIs. Most participants reported that they understood the instructions (93.0%) and found SCVS easy (90.7%). Many participants felt relaxed (93.0%), in control (88.4%) and that they had enough privacy (90.7%). Pain or discomfort were reported by 16.3% and embarrassment by 15.5%. Among the 92 (71.3%) participants who provided both a SCVS and urine sample, 60.9% preferred SCVS. Sample collection method preferences were similar between 16-19 and 20-24year-olds. In IDIs, clear instructions, privacy, trust in the service and same-day results were perceived as important facilitators to taking up SCVS. Participants frequently described feeling relaxed and confident whilst taking a SCVS. Pain and discomfort were uncommon experiences.

CONCLUSIONS

SCVS for STI testing are acceptable to young women and a feasible method of sample collection in community-based settings.

Software development process of Neotree - a data capture and decision support system to improve newborn healthcare in low-resource settings

The global priority of improving neonatal survival could be tackled through the universal implementation of cost-effective maternal and newborn health interventions. Despite 90% of neonatal deaths occurring in low-resource settings, very few evidence-based digital health interventions exist to assist healthcare professionals in clinical decision-making in these settings. To bridge this gap, Neotree was co-developed through an iterative, user-centered design approach in collaboration with healthcare professionals in the UK, Bangladesh, Malawi, and Zimbabwe. It addresses a broad range of neonatal clinical diagnoses and healthcare indicators as opposed to being limited to specific conditions and follows national and international guidelines for newborn care. This digital health intervention includes a mobile application (app) which is designed to be used by healthcare professionals at the bedside. The app enables real-time data capture and provides education in newborn care and clinical decision support via integrated clinical management algorithms. Comprehensive routine patient data are prospectively collected regarding each newborn, as well as maternal data and blood test results, which are used to inform clinical decision making at the bedside. Data dashboards provide healthcare professionals and hospital management a near real-time overview of patient statistics that can be used for healthcare quality improvement purposes. To enable this workflow, the Neotree web editor allows fine-grained customization of the mobile app. The data pipeline manages data flow from the app to secure databases and then to the dashboard. Implemented in three hospitals in two countries so far, Neotree has captured routine data and supported the care of over 21,000 babies and has been used by over 450 healthcare professionals. All code and documentation are open source, allowing adoption and adaptation by clinicians, researchers, and developers.

Late cardiac interventions in adults with congenital ventricular septal defects

Introduction

Ventricular septal defect (VSD) is one of the most common congenital heart lesions. Shunts with hemodynamic significance are usually closed early in life whereas small shunts are left without intervention. The need for late cardiac interventions in these populations is essentially unknown. The aim was to study the late cardiac interventions in adults with VSD.

Methods

The national register on congenital heart disease was searched for patients with VSD with or without associated simple cardiac defects but without complex lesions. For these patients, the last 10 years (over the age of 18) in the national patient register was searched for cardiac interventions.

Results

774 patients (mean age 39.0±14.7 years, women =50.6%), 224 (28.9%) with previous closure of VSD, were identified. The total observed time was 6920 patient years. There were 43 interventions in 41 patients (5.3%) of whom 12 had a previous closure of VSD. Twelve patients had isolated closure of VSD, 18 closure of VSD together with other cardiac surgery (one of these had repeated cardiac surgery) and 8 had only other cardiac surgery. In 4 cases, a pacemaker was implanted, of whom one together with cardiac surgery.

Conclusion

The need for cardiac interventions is relatively common in adults with a VSD, also in those without previous closure of their shunt. Our data suggests that most patients with a VSD, closed or not, should be offered periodic follow-up as approximately one out of 20 patients may encounter a complication within 10 years.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Swedish Heart-Lung Foundation

Maresin 1 Promotes Wound Healing and Socket Bone Regeneration for Alveolar Ridge Preservation

Tooth extraction results in alveolar bone resorption and is accompanied by postoperative swelling and pain. Maresin 1 (MaR1) is a proresolving lipid mediator produced by macrophages during the resolution phase of inflammation, bridging healing and tissue regeneration. The aim of this study was to examine the effects of MaR1 on tooth extraction socket wound healing in a preclinical rat model. The maxillary right first molars of Sprague-Dawley rats were extracted, and gelatin scaffolds were placed into the sockets with or without MaR1. Topical application was also given twice a week until complete socket wound closure up to 14 d. Immediate postoperative pain was assessed by 3 scores. Histology and microcomputed tomography were used to assess socket bone fill and alveolar ridge dimensional changes at selected dates. The assessments of coded specimens were performed by masked, calibrated examiners. Local application of MaR1 potently accelerated extraction socket healing. Macroscopic and histologic analysis revealed a reduced soft tissue wound opening and more rapid re-epithelialization with MaR1 delivery versus vehicle on socket healing. Under micro-computed tomography analysis, MaR1 (especially at 0.05 μg/μL) stimulated greater socket bone fill at day 10 as compared with the vehicle-treated animals, resulting in less buccal plate resorption and a wider alveolar ridge by day 21. Interestingly, an increased ratio of CD206⁺:CD68⁺ macrophages was identified in the sockets with MaR1 application under immunohistochemistry and immunofluorescence analysis. As compared with the vehicle therapy, local delivery of MaR1 reduced immediate postoperative surrogate pain score panels. In summary, MaR1 accelerated extraction wound healing, promoted socket bone fill, preserved alveolar ridge bone, and reduced postoperative pain in vivo with a rodent preclinical model. Local administration of MaR1 offers clinical potential to accelerate extraction socket wound healing for more predictable dental implant reconstruction.

Muscle-specific differences in expression and phosphorylation of the Janus kinase 2/Signal Transducer and Activator of Transcription 3 following long-term mechanical ventilation and immobilization in rats

AIM

Muscle wasting is one of the factors most strongly predicting mortality and morbidity in critically ill intensive care unit (ICU). This muscle wasting affects both limb and respiratory muscles, but the understanding of underlying mechanisms and muscle-specific differences remains incomplete. This study aimed at investigating the temporal expression and phosphorylation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in muscle wasting associated with the ICU condition to characterize the JAK/STAT proteins and the related changes leading or responding to their activation during exposure to the ICU condition.

METHODS

A novel experimental ICU model allowing long-term exposure to the ICU condition, immobilization and mechanical ventilation, was used in this study. Rats were pharmacologically paralysed by post-synaptic neuromuscular blockade and mechanically ventilated for durations varying between 6 hours and 14 days to study muscle-specific differences in the temporal activation of the JAK/STAT pathway in plantaris, intercostal and diaphragm muscles.

RESULTS

The JAK2/STAT3 pathway was significantly activated irrespective of muscle, but muscle-specific differences were observed in the temporal activation pattern between plantaris, intercostal and diaphragm muscles.

CONCLUSION

The JAK2/STAT3 pathway was differentially activated in plantaris, intercostal and diaphragm muscles in response to the ICU condition. Thus, JAK2/STAT3 inhibitors may provide an attractive pharmacological intervention strategy in immobilized ICU patients, but further experimental studies are required in the study of muscle-specific effects on muscle mass and function in response to both short- and long-term exposure to the ICU condition prior to the translation into clinical research and practice.

Weak by the machines: muscle motor protein dysfunction - a side effect of intensive care unit treatment

Intensive care interventions involve periods of mechanical ventilation, sedation and complete mechanical silencing of patients. Critical illness myopathy (CIM) is an ICU-acquired myopathy that is associated with limb muscle weakness, muscle atrophy, electrical silencing of muscle and motor proteinopathy. The hallmark of CIM is a preferential muscle myosin loss due to increased catabolic and reduced anabolic activity. The ubiquitin proteasome pathway plays an important role, apart from recently identified novel mechanisms affecting non-lysosomal protein degradation or autophagy. CIM is not reproduced by pure disuse atrophy, denervation atrophy, steroid-induced atrophy or septic myopathy, although combinations of high-dose steroids and denervation can mimic CIM. New animal models of critical illness and ICU treatment (i.e. mechanical ventilation and complete immobilization) provide novel insights regarding the time course of protein synthesis and degradation alterations, and the role of protective chaperone activities in the process of myosin loss. Altered mechano-signalling seems involved in triggering a major part of myosin loss in experimental CIM models, and passive loading of muscle potently ameliorates the CIM phenotype. We provide a systematic overview of similarities and distinct differences in the signalling pathways involved in triggering muscle atrophy in CIM and isolated trigger factors. As preferential myosin loss is mostly determined from biochemistry analyses providing no spatial resolution of myosin loss processes within myofibres, we also provide first results monitoring myosin signal intensities during experimental ICU intervention using multi-photon Second Harmonic Generation microscopy. Our results confirm that myosin loss is an evenly distributed process within myofibres rather than being confined to hot spots.

Regenerative Medicine for Periodontal and Peri-implant Diseases

The balance between bone resorption and bone formation is vital for maintenance and regeneration of alveolar bone and supporting structures around teeth and dental implants. Tissue regeneration in the oral cavity is regulated by multiple cell types, signaling mechanisms, and matrix interactions. A goal for periodontal tissue engineering/regenerative medicine is to restore oral soft and hard tissues through cell, scaffold, and/or signaling approaches to functional and aesthetic oral tissues. Bony defects in the oral cavity can vary significantly, ranging from smaller intrabony lesions resulting from periodontal or peri-implant diseases to large osseous defects that extend through the jaws as a result of trauma, tumor resection, or congenital defects. The disparity in size and location of these alveolar defects is compounded further by patient-specific and environmental factors that contribute to the challenges in periodontal regeneration, peri-implant tissue regeneration, and alveolar ridge reconstruction. Efforts have been made over the last few decades to produce reliable and predictable methods to stimulate bone regeneration in alveolar bone defects. Tissue engineering/regenerative medicine provide new avenues to enhance tissue regeneration by introducing bioactive models or constructing patient-specific substitutes. This review presents an overview of therapies (e.g., protein, gene, and cell based) and biomaterials (e.g., resorbable, nonresorbable, and 3-dimensionally printed) used for alveolar bone engineering around teeth and implants and for implant site development, with emphasis on most recent findings and future directions.

Epigenetic Modifications of Histones in Periodontal Disease

Periodontitis is a chronic infectious disease driven by dysbiosis, an imbalance between commensal bacteria and the host organism. Periodontitis is a leading cause of tooth loss in adults and occurs in about 50% of the US population. In addition to the clinical challenges associated with treating periodontitis, the progression and chronic nature of this disease seriously affect human health. Emerging evidence suggests that periodontitis is associated with mechanisms beyond bacteria-induced protein and tissue degradation. Here, we hypothesize that bacteria are able to induce epigenetic modifications in oral epithelial cells mediated by histone modifications. In this study, we found that dysbiosis in vivo led to epigenetic modifications, including acetylation of histones and downregulation of DNA methyltransferase 1. In addition, in vitro exposure of oral epithelial cells to lipopolysaccharides resulted in histone modifications, activation of transcriptional coactivators, such as p300/CBP, and accumulation of nuclear factor-κB (NF-κB). Given that oral epithelial cells are the first line of defense for the periodontium against bacteria, we also evaluated whether activation of pathogen recognition receptors induced histone modifications. We found that activation of the Toll-like receptors 1, 2, and 4 and the nucleotide-binding oligomerization domain protein 1 induced histone acetylation in oral epithelial cells. Our findings corroborate the emerging concept that epigenetic modifications play a role in the development of periodontitis.

The Sick and the Weak: Neuropathies/Myopathies in the Critically Ill

Critical illness polyneuropathies (CIP) and myopathies (CIM) are common complications of critical illness. Several weakness syndromes are summarized under the term intensive care unit-acquired weakness (ICUAW). We propose a classification of different ICUAW forms (CIM, CIP, sepsis-induced, steroid-denervation myopathy) and pathophysiological mechanisms from clinical and animal model data. Triggers include sepsis, mechanical ventilation, muscle unloading, steroid treatment, or denervation. Some ICUAW forms require stringent diagnostic features; CIM is marked by membrane hypoexcitability, severe atrophy, preferential myosin loss, ultrastructural alterations, and inadequate autophagy activation while myopathies in pure sepsis do not reproduce marked myosin loss. Reduced membrane excitability results from depolarization and ion channel dysfunction. Mitochondrial dysfunction contributes to energy-dependent processes. Ubiquitin proteasome and calpain activation trigger muscle proteolysis and atrophy while protein synthesis is impaired. Myosin loss is more pronounced than actin loss in CIM. Protein quality control is altered by inadequate autophagy. Ca(2+) dysregulation is present through altered Ca(2+) homeostasis. We highlight clinical hallmarks, trigger factors, and potential mechanisms from human studies and animal models that allow separation of risk factors that may trigger distinct mechanisms contributing to weakness. During critical illness, altered inflammatory (cytokines) and metabolic pathways deteriorate muscle function. ICUAW prevention/treatment is limited, e.g., tight glycemic control, delaying nutrition, and early mobilization. Future challenges include identification of primary/secondary events during the time course of critical illness, the interplay between membrane excitability, bioenergetic failure and differential proteolysis, and finding new therapeutic targets by help of tailored animal models.

A study on particles and some microbial markers in waterpipe tobacco smoke

Waterpipe smoking is becoming increasingly popular worldwide. Research has shown that cigarette smoke, in addition to hundreds of carcinogenic and otherwise toxic compounds, may also contain compounds of microbiological origin. In the present study we analyzed waterpipe smoke for some microbial compounds. Both of the two markers studied, viz 3-hydroxy fatty acids of bacterial lipopolysaccharide (LPS) and ergosterol of fungal biomass, were found in waterpipe tobacco, in amounts similar as previously found in cigarette tobacco, and in smoke. Waterpipe mainstream smoke contained on average 1800 pmol LPS and 84.4 ng ergosterol produced per session. An average concentration of 2.8 pmol/m(3) of LPS was found in second hand smoke during a 1-2-h waterpipe smoking session while ergosterol was not detected; corresponding concentrations from smoking five cigarettes were 22.2 pmol/m(3) of LPS and 87.5 ng/m(3) of ergosterol. This is the first time that waterpipe smoking has been shown to create a bioaerosol. In the present study we also found that waterpipe smoking generated several polycyclic aromatic hydrocarbons, carbon monoxide, and high fraction of small (<200 nm) particles that may have adverse effects on human health upon inhalation.

Cellular composition of long-standing gingivitis and periodontitis lesions

BACKGROUND AND OBJECTIVE

Insufficient information on the cellular composition of long-standing gingivitis lesions without signs of attachment loss makes an understanding of differences in cellular composition between "destructive" and "nondestructive" periodontal lesions difficult. The aim of the current study was to analyze differences in cell characteristics between lesions representing long-standing gingivitis and severe periodontitis.

MATERIAL AND METHODS

Two groups of patients were recruited. One group consisted of 36 patients, 33-67 years of age, with severe generalized periodontitis (periodontitis group). The second group consisted of 28 patients, 41-70 years of age, with overt signs of gingival inflammation but no attachment loss (gingivitis group). From each patient a gingival biopsy was obtained from one selected diseased site and prepared for immunohistochemical analysis.

RESULTS

Periodontitis lesions were twice as large and contained significantly larger proportions, numbers and densities of cells positive for CD138 (plasma cells) and CD68 (macrophages) than did gingivitis lesions. The proportion of B cells that expressed the additional CD5 marker (B-1a cells) was significantly larger in periodontitis lesions than in gingivitis lesions. The densities of T cells and B cells did not differ between periodontitis lesions and gingivitis lesions. T cells were not the dominating cell type in gingivitis lesions, as B cells together with their subset plasma cells comprised a larger number and proportion than T cells.

CONCLUSION

Periodontitis lesions at teeth with advanced attachment and bone loss exhibit quantitative and qualitative differences in relation to gingivitis lesions at teeth with no attachment and bone loss. It is suggested that the large number and high density of plasma cells are the hallmarks of advanced periodontitis lesions and the most conspicuous difference in relation to long-standing gingivitis lesions.

The thyroid receptor β modulator GC-1 reduces atherosclerosis in ApoE deficient mice

Thyroid hormone reduces plasma cholesterol and increases expression of low-density lipoprotein receptor (LDL-R) in liver, an effect mediated by thyroid receptor β (TRβ). The selective TRβ modulator GC-1 also enhances several steps in reverse cholesterol transport and can decrease serum cholesterol independently of LDL-R. To test whether GC-1 reduces atherosclerosis and to determine which mechanisms are active, we treated ApoE deficient mice with atherogenic diet ± GC-1. GC-1 reduced cholesteryl esters in aorta after 20 weeks. Serum free and esterified cholesterol were reduced after 1 and 10 weeks, but not 20 weeks. Hepatic bile acid synthesis and LDL-R expression was elevated after 1, 10 and 20 weeks, without changes in hepatic de novo cholesterol synthesis. GC-1 increased faecal neutral sterols and reduced serum campesterol after 1 week, indicating reduced intestinal cholesterol absorption. After 20 weeks, GC-1 increased faecal bile acids, but not faecal neutral sterols. Hepatic scavenger receptor B1 (SR-B1) expression was decreased by GC-1. We conclude that GC-1 delays the onset of atherosclerosis in ApoE deficient mice. Since ApoE is needed for hepatic cholesterol reabsorption by LDL-R, this supports the idea that GC-1 reduces serum cholesterol independently of LDL-R by increasing hepatic bile acid synthesis. GC-1 lipid-lowering effects in ApoE deficient mice may also be partly due to reduced intestinal cholesterol absorption. Since reductions in serum cholesterol are reversed at longer times, these GC-1 dependent effects may not be enough for sustained cholesterol reduction in long term treatments.

Time course analysis of mechanical ventilation-induced diaphragm contractile muscle dysfunction in the rat

Controlled mechanical ventilation (CMV) plays a key role in triggering the impaired diaphragm muscle function and the concomitant delayed weaning from the respirator in critically ill intensive care unit (ICU) patients. To date, experimental and clinical studies have primarily focused on early effects on the diaphragm by CMV, or at specific time points. To improve our understanding of the mechanisms underlying the impaired diaphragm muscle function in response to mechanical ventilation, we have performed time-resolved analyses between 6 h and 14 days using an experimental rat ICU model allowing detailed studies of the diaphragm in response to long-term CMV. A rapid and early decline in maximum muscle fibre force and preceding muscle fibre atrophy was observed in the diaphragm in response to CMV, resulting in an 85% reduction in residual diaphragm fibre function after 9-14 days of CMV. A modest loss of contractile proteins was observed and linked to an early activation of the ubiquitin proteasome pathway, myosin:actin ratios were not affected and the transcriptional regulation of myosin isoforms did not show any dramatic changes during the observation period. Furthermore, small angle X-ray diffraction analyses demonstrate that myosin can bind to actin in an ATP-dependent manner even after 9-14 days of exposure to CMV. Thus, quantitative changes in muscle fibre size and contractile proteins are not the dominating factors underlying the dramatic decline in diaphragm muscle function in response to CMV, in contrast to earlier observations in limb muscles. The observed early loss of subsarcolemmal neuronal nitric oxide synthase activity, onset of oxidative stress, intracellular lipid accumulation and post-translational protein modifications strongly argue for significant qualitative changes in contractile proteins causing the severely impaired residual function in diaphragm fibres after long-term mechanical ventilation. For the first time, the present study demonstrates novel changes in the diaphragm structure/function and underlying mechanisms at the gene, protein and cellular levels in response to CMV at a high temporal resolution ranging from 6 h to 14 days.

What determines myonuclear domain size?

The muscle cell is multinuclear and each nucleus controls transcriptional activity in the surrounding territory of cytoplasm called myonuclear domain (MND). MND size varies with the fiber type and is inversely proportional to the muscle fiber oxidative capacity. Change in MND size precedes change in myonuclei count during post-natal growth and most conditions of muscle fiber hypertrophy, suggesting that the myonuclei have the ability to enhance their synthetic capacity according to cell size, functional and metabolic needs. MND size has a "ceiling" limit during hypertrophic process beyond which extra myonuclei are donated by satellite cell to support further muscle growth. During ageing-related atrophy, myonuclei are not lost but an unequal distribution is reported. Ageing myonucleus still responds to resistant exercise and hormone replacement therapy (HRT) by enhancing its transcriptional capacity. Thus the MND size is far from constant and modulates itself to contribute to the muscle remodeling in various conditions.

Detection of an aging-related increase in advanced glycation end products in fast- and slow-twitch skeletal muscles in the rat

Glycation, a non-enzymatic addition of reducing sugars to ε-amino groups of proteins, is a post-translational modification that results in the formation of irreversible advanced glycation end products (AGEs). Ageing related decline in myofibrillar protein function is effected by a number of structural and functional modifications including glycation. Functional properties of skeletal muscles, such as maximum velocity of unloaded shortening, are known to be profoundly affected by ageing at the motor unit, cellular and tissue levels. However, the contribution of protein modifications to a decline in muscle function is not well understood. In this study we measured AGEs of intracellular and sarcolemmal proteins, using an anti-AGE antibody in soleus (SOL) and extensor digiotorum longus (EDL) muscles of male and female rats of five different age groups. Using a fluorescent secondary antibody to visualize AGEs in the confocal microscope, we found that myosin is glycated in both fiber types in all age groups; an ageing related increase in AGEs was observed in both intracellular and sarcolemmal regions in all age groups, with the exception of sarcolemma of SOL (unchanged) and EDL (reduced) in female rats; the greatest concentration of AGEs was found intracellularly in the SOL of the oldest age group (27-30) of females. While an ageing related decline in motor properties can be partially attributed to the observed increase in myofibrillar protein glycation, our results also indicate that intracellular and the less well studied sarcolemmal protein modification likely contribute to an aging-related decline in muscle function. Further studies are required to establish a link between the observed ageing related increase in glycation and muscle function at the motor unit, cellular and tissue levels.

Bacterial and fungal markers in tobacco smoke

Previous research has demonstrated that cigarette smoke contains bacterial and fungal components including lipopolysaccharide (LPS) and ergosterol. In the present study we used gas chromatography-mass spectrometry to analyze tobacco as well as mainstream and second hand smoke for 3-hydroxy fatty acids (3-OH FAs) of 10 to 18 carbon chain lengths, used as LPS markers, and ergosterol, used as a marker of fungal biomass. The air concentrations of LPS were 0.0017 n mol/m(3) (N=5) and 0.0007/m(3) (N=6) in the smoking vs. non-smoking rooms (p=0.0559) of the studied private houses, and 0.0231 n mol/m(3) (N=5) vs. 0.0006 n mol/m(3) (N=5) (p=0.0173), respectively, at the worksite. The air concentrations of ergosterol were also significantly higher in rooms with ongoing smoking than in rooms without smoking. A positive correlation was found between LPS and ergosterol in rooms with smoking but not in rooms without smoking. 3-OH C14:0 was the main 3-OH FA, followed by 3-OH C12:0, both in mainstream and second hand smoke and in phenol:water smoke extracts prepared in order to purify the LPS. The Limulus activity of the phenolic phase of tobacco was 3900 endotoxin units (EU)/cigarette; the corresponding amount of the smoke, collected on filters from 8 puffs, was 4 EU/cigarette. Tobacco smoking has been associated with a range of inflammatory airway conditions including COPD, asthma, bronchitis, alveolar hypersensitivity etc. Significant levels of LPS and ergosterol were identified in tobacco smoke and these observations support the hypothesis that microbial components of tobacco smoke contribute to inflammation and airway disease.

Apoptosis of mouse mast cells is reciprocally regulated by the IgG receptors FcγRIIB and FcγRIIIA

BACKGROUND

Mast cells are important effector cells in allergy. They usually have a long life span and resist cell death induction. Fcγ receptor- and IgG immune complex-mediated apoptosis has been demonstrated in B-lineage cells, but not in mast cells. The aim of the current study was to investigate whether mast cells could respond to apoptosis induction by IgG immune complex aggregation of Fcγ receptors. It is known that mouse mast cells express the low-affinity Fcγ receptors FcγRIIB and FcγRIIIA, which bind IgG especially in the form of antigen-IgG immune complexes.

METHODS

Mouse bone marrow-derived cultured mast cells were examined for surface expression of FcγRIIB and FcγRIIIA. Apoptosis of such cells from wild-type, FcγRIIB(-/-) or FcγRIIIA(-/-) mice was measured following receptor aggregation by IgG immune complexes.

RESULTS

Our data demonstrate that aggregation of either FcγRIIB or FcγRIIIA by IgG immune complexes induced apoptosis of mouse bone marrow-derived cultured mast cells. However, mast cells expressing both FcγRIIB and FcγRIIIA were able to resist cell death induction by IgG immune complexes.

CONCLUSION

Our findings reveal a fine-tuning system for regulating mast cell apoptosis through aggregating Fcγ receptors by IgG immune complexes. Such apoptosis regulation may have a substantial impact on mast cell homeostasis during allergic inflammation.

Apoptosis of mouse mast cells is reciprocally regulated by the IgG receptors FcγRIIB and FcγRIIIA

BACKGROUND

Mast cells are important effector cells in allergy. They usually have a long life span and resist cell death induction. Fcγ receptor- and IgG immune complex-mediated apoptosis has been demonstrated in B-lineage cells, but not in mast cells. The aim of the current study was to investigate whether mast cells could respond to apoptosis induction by IgG immune complex aggregation of Fcγ receptors. It is known that mouse mast cells express the low-affinity Fcγ receptors FcγRIIB and FcγRIIIA, which bind IgG especially in the form of antigen-IgG immune complexes.

METHODS

Mouse bone marrow-derived cultured mast cells were examined for surface expression of FcγRIIB and FcγRIIIA. Apoptosis of such cells from wild-type, FcγRIIB(-/-) or FcγRIIIA(-/-) mice was measured following receptor aggregation by IgG immune complexes.

RESULTS

Our data demonstrate that aggregation of either FcγRIIB or FcγRIIIA by IgG immune complexes induced apoptosis of mouse bone marrow-derived cultured mast cells. However, mast cells expressing both FcγRIIB and FcγRIIIA were able to resist cell death induction by IgG immune complexes.

CONCLUSION

Our findings reveal a fine-tuning system for regulating mast cell apoptosis through aggregating Fcγ receptors by IgG immune complexes. Such apoptosis regulation may have a substantial impact on mast cell homeostasis during allergic inflammation.

Co-occurrence of toxic bacterial and fungal secondary metabolites in moisture-damaged indoor environments

Toxic microbial secondary metabolites have been proposed to be related to adverse health effects observed in moisture-damaged buildings. Initial steps in assessing the actual risk include the characterization of the exposure. In our study, we applied a multi-analyte tandem mass spectrometry-based methodology on sample materials of severely moisture-damaged homes, aiming to qualitatively and quantitatively describe the variety of microbial metabolites occurring in building materials and different dust sample types. From 69 indoor samples, all were positive for at least one of the 186 analytes targeted and as many as 33 different microbial metabolites were found. For the first time, the presence of toxic bacterial metabolites and their co-occurrence with mycotoxins were shown for indoor samples. The bacterial compounds monactin, nonactin, staurosporin and valinomycin were exclusively detected in building materials from moist structures, while chloramphenicol was particularly prevalent in house dusts, including settled airborne dust. These bacterial metabolites are highly bioactive compounds produced by Streptomyces spp., a group of microbes that is considered a moisture damage indicator in indoor environments. We show that toxic bacterial metabolites need to be considered as being part of very complex and diverse microbial exposures in 'moldy' buildings.

PRACTICAL IMPLICATIONS

Bacterial toxins co-occur with mycotoxins in moisture-damaged indoor environments. These compounds are measurable also in settled airborne dust, indicating that inhalation exposure takes place. In attempts to characterize exposures to microbial metabolites not only mycotoxins but also bacterial metabolites have to be targeted by the analytical methods applied. We recommend including analysis of samples of outdoor air in the course of future indoor assessments, in an effort to better understand the outdoor contribution to the indoor presence of microbial toxins. There is a need for a sound risk assessment concerning the exposure to indoor microbial toxins at concentrations detectable in moisture-damaged indoor environments.

There is no slowing of motility speed with increased body size in rat, human, horse and rhinoceros independent on temperature and skeletal muscle myosin isoform

AIM

The predictions of scaling of skeletal muscle shortening velocity made by A.V. Hill 60-years ago have proven to be remarkably accurate at the cellular level. The current investigation looks to extend the study of scaling of contractile speed to the level of the molecular motor protein myosin at both physiological and unphysiological low temperatures.

METHODS

A single muscle cell in vitro motility assay to test myosin function, i.e. myosin extracted from short single muscle fibre segments, was used in four species representing a 5 500-fold difference in body mass (rat, man, horse and rhinoceros) at temperatures ranging from 15 to 35 °C.

RESULTS

The in vitro motility speed increased as the temperature of the assay increased, but a more profound effect was observed on the slower isoforms, narrowing the relative differences between fast and slow myosin heavy chain (MyHC) isoforms at physiological temperature in all species. The in vitro motility speed varied according to MyHC isoform within each species: I < IIa < IIx < IIb, but the expected scaling relationship within orthologous myosin isoforms was not observed at any temperature.

CONCLUSION

The scaling effect of body size and limb length on shortening velocity at the muscle fibre level, i.e. the decreasing shortening velocity associated with increasing body weight and limb length, was not confirmed at the motor protein level when including mammals of very large size. Thus, other factors than myosin structure and function appear to cause this scaling effect and thin filament isoform expression or myofilament lattice spacing are forwarded as alternative underlying factors.

Fatty acid profiles in smokers with chronic periodontitis

We hypothesized that tobacco smoke induces alterations to the 3-OH fatty acids present in lipid A in a manner consistent with a microflora of reduced inflammatory potential. Whole saliva samples and full-mouth clinical periodontal recordings were obtained from persons with (22 smokers; 15 non-smokers) and without (14 smokers; 15 non-smokers) chronic periodontitis. Clear differences in the contributions of multiple saturated 3-OH fatty acid species were noted in the group with disease compared with healthy individuals. Increases in the long-chain fatty acids associated with anaerobic bacterial periodontopathogens, particularly 3-OH-C(i17.0) (146.7%, relative to controls), were apparent. Significant reductions in the 3-OH fatty acids associated with the consensus (high potency) enteric LPS structure (3-OH-C(12.0) and 3-OH-C(14.0); 33.3% and 15.8% reduction, respectively) were noted in smokers compared with non-smokers with chronic periodontitis. Thus, smoking is associated with specific structural alterations to the lipid-A-derived 3-OH fatty acid profile in saliva that are consistent with an oral microflora of reduced inflammatory potential. These findings provide much-needed mechanistic insight into the established clinical conundrum of increased infection with periodontal pathogens but reduced clinical inflammation in smokers.

Detection of bacterial contamination in cultures of eucaryotic cells by gas chromatography-mass spectrometry

The use of gas chromatography-mass spectrometry for early detection of bacterial contaminations in cultures of baker's yeast, Penicillium chrysogenum, and an animal cell line was evaluated; muramic acid and characteristic cellular fatty acids were used as analytes. By analyzing branched-chain and cyclopropane-substituted fatty acids as methyl esters, Staphylococcus epidermidis, Bacillus subtilis, Lactobacillus reuteri, Enterobacter cloacae, and Pseudomonas fluorescens were detected in a 500-fold excess (w/w) of baker's yeast; the amounts injected corresponded to 300 ng (dry mass) of the bacteria. Contamination with Bacillus was detected in cultures of Penicillium chrysogenum and animal cells by analyzing muramic acid, both as its alditol acetate derivative, using electron impact ionization, and its trifluoroacetyl methyl glycoside derivative, using negative ion-chemical ionization. The trifluoroacetylated derivative was detected in injected amounts corresponding to 1 x 10(3) bacterial cells in the contaminated animal cell line, whereas amounts corresponding to 1 x 10(5) bacteria were required for detection of the alditol acetate derivative; the amounts in the original samples were 5 x 10(5) and 5 x 10(6), respectively. However, the alditol acetate method exhibited lower chemical interferences than the trifluoroacetyl methyl glycoside procedure. The results show the potential of using gas chromatographic-mass spectrometric analysis of cellular constituents for the detection of bacterial contaminations in eucaryotic cultures as an alternative to conventional microbiological methods.