Recognising the importance and impact of Imaging Scientists: Global guidelines for establishing career paths within core facilities

In the dynamic landscape of scientific research, imaging core facilities are vital hubs propelling collaboration and innovation at the technology development and dissemination frontier. Here, we present a collaborative effort led by Global BioImaging (GBI), introducing international recommendations geared towards elevating the careers of Imaging Scientists in core facilities. Despite the critical role of Imaging Scientists in modern research ecosystems, challenges persist in recognising their value, aligning performance metrics and providing avenues for career progression and job security. The challenges encompass a mismatch between classic academic career paths and service-oriented roles, resulting in a lack of understanding regarding the value and impact of Imaging Scientists and core facilities and how to evaluate them properly. They further include challenges around sustainability, dedicated training opportunities and the recruitment and retention of talent. Structured across these interrelated sections, the recommendations within this publication aim to propose globally applicable solutions to navigate these challenges. These recommendations apply equally to colleagues working in other core facilities and research institutions through which access to technologies is facilitated and supported. This publication emphasises the pivotal role of Imaging Scientists in advancing research programs and presents a blueprint for fostering their career progression within institutions all around the world.

Effects of meditation on physiological and metabolic parameters in patients with type 2 diabetes mellitus "MindDM": study protocol for a randomized controlled trial

BACKGROUND

Sri Lanka is faced with the challenge of managing a large population with diabetes mellitus by 2030. Psychological stress plays a major role in disease outcome by exerting physiological, psychological and social effects on individuals with chronic disorders. Meditation-based interventions have positive effects on the management of stress and diabetes, which are mediated via modulation of neuro-humoral mechanisms and autonomic functions, among others. Mechanisms of bio-physiological effects of meditation are considered to be through reduction of stress hormones, improvement of insulin resistance and improvement of autonomic dysfunction.

METHODS

This study will be conducted as an open-label, randomized controlled clinical trial in the Faculty of Medicine, University of Colombo. The aim is to investigate the effects of meditation on glycaemic control and possible mechanisms of how meditation affects glycaemic control in patients with type 2 diabetes. The study was approved by the Ethics Review Committee of the Faculty of Medicine, University of Colombo (ERC/2019/094). Patients who are attending the professorial unit medical clinic with type 2 diabetes (172 in total) will be recruited based on inclusion-exclusion criteria. Patients who have never meditated or rarely meditated (less than once every three months) will be randomized using block randomization to meditation and waitlisted arms (1:1 allocation ratio). The meditation arm will undergo a mindfulness meditation program (selected after studying several meditation methods) conducted by a qualified instructor weekly for a period of 12 weeks in addition to usual care, while the waitlisted arm will only receive usual care. Daily meditation practices will be recorded in a diary. The primary outcome measure is HbA1c. Secondary outcome measures are fasting blood sugar, fructosamine, insulin resistance (calculated using fasting serum insulin), 24-h urinary cortisol, body mass index, cardiac autonomic reflex testing (Ewing's battery of tests) and orocecal transit time using hydrogen breath analysis. All these will be done prior to commencement of the intervention and after 3 months in both arms. Data will be analysed using SPSS V-23.

DISCUSSION

This study aims to identify the effect of mindfulness meditation on glycaemic control and the possible mechanisms (neuro humoral and autonomic functions) by which beneficial effects are mediated.

TRIAL REGISTRATION

Registered under Sri Lanka Clinical Trial Registry: SLCTR/2021/015 The Universal Trial Number (UTN) U1111-1266-8640.

Dengue and leptospirosis infection during the coronavirus 2019 outbreak in Sri Lanka

A significant decrease in dengue fever cases and a contrasting increase in leptospirosis cases were reported for the second quarter of 2020 compared with 2019 in Sri Lanka. In the absence of significant environmental and weather-related differences to account for these changes in incidence, we investigated the possibility that the effects of the COVID-19 pandemic on public health, social behaviour and the restrictions imposed during the lockdown influenced the fluctuations in dengue and leptospirosis infections.

Antibacterial and synergistic activity of 6β-hydroxy-3-oxolup-20(29)-en-28-oic acid (6β-hydroxy betunolic acid) isolated from Schumacheria castaneifolia vahl

Multi- drug resistant microbial pathogens are a serious global health problem and thus new antibacterial agents, which are effective both alone and in combination with traditional antibiotics, are urgently needed. Hence, the objective of the present study was to investigate the antibacterial activity of 6β-hydroxy-3-oxolup-20(29)-en-28-oic acid (6β-hydroxy betunolic acid) isolated from the bark of Schumacheria castaneifolia and its effect when combined with oxacillin. Antibacterial potential of 6β-hydroxy betunolic acid alone was performed using broth micro dilution assay against sixteen bacterial strains which included eight standard strains [Staphylococcus aureus (ATCC 29213 and ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 35218 and ATCC 25922), carbapenemase producing Kebsiella pneumonia (ATCC BAA 1705), carbapenemase non-producing K. pneumonia (ATCC BAA 1706) and Pseudomonas aeruginosa (ATCC 27853)] and four strains each of clinically isolated meropenem resistant Acinetobactor sp. and methicillin resistant S. aureus (MRSA) which were included in the urgent threat list and serious threat list, respectively in 2019 by the Centers for Disease Control and Prevention in the United States. Its effect when combined with oxacillin was tested against S. aureus (ATCC 29213) and MRSAs using a checkerboard dilution method. The results indicated that 6β-hydroxy betunolic acid had antibacterial activity against the tested Gram positive organisms with MICs ranging from 16 to 32 mg L^-1 (MIC of oxacillin and meropenem ranged from 0.25-16 and 0.03-128 mg L^-1 respectively). The high MIC values (>1024 mg L^-1) of 6β-hydroxy betunolic acid against Gram negative strains indicated a likely lack of activity. Further, 6β-hydroxy betunolic acid exhibited synergistic effect with oxacillin against Staphylococcus aureus (0.49) and showed an additive effect against all the tested MRSAs. The present study suggested that the antibacterial activity of the 6β-hydroxy betunolic acid is restricted to Staphylococcus isolates and possibly Enterococcus faecalis. Further testing on different types of Gram positives and identification of the exact mechanism of action would be of importance.

COVID-19 Epidemic in Sri Lanka: A Mathematical and Computational Modelling Approach to Control

The ongoing COVID-19 outbreak that originated in the city of Wuhan, China, has caused a significant damage to the world population and the global economy. It has claimed more than 0.8 million lives worldwide, and more than 27 million people have been infected as of 07th September 2020. In Sri Lanka, the first case of COVID-19 was reported late January 2020 which was a Chinese national and the first local case was identified in the second week of March. Since then, the government of Sri Lanka introduced various sequential measures to improve social distancing such as closure of schools and education institutes, introducing work from home model to reduce the public gathering, introducing travel bans to international arrivals, and more drastically, imposed island wide curfew expecting to minimize the burden of the disease to the Sri Lankan health system and the entire community. Currently, there are 3123 cases with 12 fatalities and also, it was reported that 2925 patients have recovered and are discharged from hospitals, according to the Ministry of Health, Sri Lanka. In this study, we use the SEIR conceptual model and its modified version by decomposing infected patients into two classes: patients who show mild symptoms and patients who tend to face severe respiratory problems and are required to be treated in intensive care units. We numerically simulate the models for about a five-month period reflecting the early stage of the epidemic in the country, considering three critical parameters of COVID-19 transmission mainly in the Sri Lankan context: efficacy of control measures, rate of overseas imported cases, and time to introduce social distancing measures by the respective authorities.

Post-stroke Quality of Life Index: A quality of life tool for stroke survivors from Sri Lanka

Background

Burden of stroke is rising due to the demographic and epidemiological transitions in Sri Lanka. Assessment of success of stroke-management requires tools to assess the quality of life (QOL) of stroke survivors. Most of currently used QOL tools are developed in high-income countries and may not reflect characteristics relevant to resource-constrained countries. The aim was to develop and validate a new QOL tool for stroke survivors in Sri Lanka.

Methods

The COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist was referred. A conceptual framework was prepared. Item generation was done reviewing the existing QOL tools, inputs from experts and from stroke survivors. Non-statistical item reduction was done for the 36 generated items with modified-Delphi technique. Retained 21 items were included in the draft tool. A cross sectional study was done with 180 stroke survivors. Exploratory Factor Analysis was done and identified factors were subjected to varimax rotation. Further construct validity was tested with 6 a-priori hypothesis using already validated tools (SF-36, EQ-5D-3 L) and a formed construct. Internal consistency reliability was assessed with Cronbach alpha.

Results

Four factors identified with principal-component-analysis explained 72.02% of the total variance. All 21 items loaded with a level > 0.4. The developed tool was named as the Post-stroke QOL Index (PQOLI). Four domains were named as “physical and social function”, “environment”, “financial-independence” and “pain and emotional-wellbeing”. Four domain scores of PQOLI correlated as expected with the SF-36, EQ-5D Index and EQ-5D-VAS scores. Higher domain scores were obtained for ambulatory-group than the hospitalized-group. Higher scores for financial-independence domain were obtained for the group without financial-instability. Five a-priori hypothesis were completely proven to be true. Cronbach-alpha level ranged from 0.682 to 0.906 for the four domains.

Conclusions

There is first evidence for sufficient construct validity of the PQOLI as a valid QOL tool for measuring the QOL of stroke survivors with satisfactory internal consistency reliability.

Impedance Plethysmography as an Alternative Measure of Reactive Hyperemia

Peripheral vascular flow in response to induced reactive hyperemia of the radial artery is used as a benchmark for non-invasive assessment of the endothelial function. As an alternative to standard modalities, this study investigates the suitability of impedance plethysmography to estimate peripheral vascular flow variations associated with the reactive hyperemia process. Results indicate a consistent variation of bio-impedance during the reactive hyperemia process at higher measurement frequencies and these variations are compatible with a standard tissue impedance model. Further, calculated features of bioimpedance has shown the capability of differentiating healthy and diabetic groups which is useful in estimating the endothelial dysfunction.

Pneumonia hospitalisation and case-fatality rates in older Australians with and without risk factors for pneumococcal disease: implications for vaccine policy

Community-acquired pneumonia (CAP) results in substantial numbers of hospitalisations and deaths in older adults. There are known lifestyle and medical risk factors for pneumococcal disease but the magnitude of the additional risk is not well quantified in Australia. We used a large population-based prospective cohort study of older adults in the state of New South Wales (45 and Up Study) linked to cause-specific hospitalisations, disease notifications and death registrations from 2006 to 2015. We estimated the age-specific incidence of CAP hospitalisation (ICD-10 J12-18), invasive pneumococcal disease (IPD) notification and presumptive non-invasive pneumococcal CAP hospitalisation (J13 + J18.1, excluding IPD), comparing those with at least one risk factor to those with no risk factors. The hospitalised case-fatality rate (CFR) included deaths in a 30-day window after hospitalisation. Among 266 951 participants followed for 1 850 000 person-years there were 8747 first hospitalisations for CAP, 157 IPD notifications and 305 non-invasive pneumococcal CAP hospitalisations. In persons 65-84 years, 54.7% had at least one identified risk factor, increasing to 57.0% in those ⩾85 years. The incidence of CAP hospitalisation in those ⩾65 years with at least one risk factor was twofold higher than in those without risk factors, 1091/100 000 (95% confidence interval (CI) 1060-1122) compared with 522/100 000 (95% CI 501-545) and IPD in equivalent groups was almost threefold higher (18.40/100 000 (95% CI 14.61-22.87) vs. 6.82/100 000 (95% CI 4.56-9.79)). The CFR increased with age but there were limited difference by risk status, except in those aged 45 to 64 years. Adults ⩾65 years with at least one risk factor have much higher rates of CAP and IPD suggesting that additional risk factor-based vaccination strategies may be cost-effective.

Detection of Diabetes by Macrovascular Tortuosity of Superior Bulbar Conjunctiva

More than 8% of world population have diabetes which causes long term complications such as retinopathy, neuropathy, nephropathy and foot ulcers. Growing patient numbers has prompted large scale screening methods to detect early symptoms of diabetes (rather than elevated blood glucose levels which is a late symptom). Vascular tortuosity (twisted and curved nature of blood vessels) in retinal fundus images has proven to reflect the effect of diabetes on macrovasculature. However, large scale patient screening using retinal fundus images has limitations due to the requirement of a retinal camera. Therefore, we hypothesize that the vasculature of superior bulbar conjunctiva which could be captured using a regular camera could be used to measure tortuosity instead of retinal fundus images enabling mass screening.To test this hypothesis, a total of 168 scleral images were acquired from 50 healthy subjects and 34 diabetic patients using a digital camera. The sclera region was segmented using Chan-Vese algorithm and macrovasculature of superior bulbar conjunctiva was segmented using B-COSFIRE filters. Results revealed that the superior bulbar conjunctival macrovascular tortuosity of diabetic patients was significantly less than that of non-diabetic group (p-value =0.015). A similar result was yielded (p-value =0.049) from a group of participants who were less than 40 years old which excluded the age related variation of tortuosity.

Effectiveness of a 3 + 0 pneumococcal conjugate vaccine schedule against invasive pneumococcal disease among a birth cohort of 1.4 million children in Australia

BACKGROUND

Most studies use indirect cohort or case-control methods to estimate vaccine effectiveness (VE) of 7- and 13-valent pneumococcal conjugate vaccines (PCV7 and PCV13) against invasive pneumococcal disease (IPD). Neither method can measure the benefit vaccination programs afford the unvaccinated and many studies were unable to estimate dose-specific VE. We linked Australia's national immunisation register with health data from two states to calculate IPD incidence by vaccination status and VE for a 3 + 0 PCV schedule (doses at 2, 4, 6 months, no booster) among a cohort of 1.4 million births.

METHODS

Births records for 2001-2012 were probabilistically linked to IPD notifications, hospitalisations, deaths, and vaccination history (available until December 2013). IPD rates in vaccinated and unvaccinated children <2 years old were compared using Cox proportional hazards models (adjusting for potential confounders), with VE = (1 - adjusted hazard ratio) × 100. Separate models were performed for all-cause, PCV7, PCV13 and PCV13-non-PCV7 serotype-specific IPD, and for Aboriginal and non-Aboriginal children.

RESULTS

Following introduction of universal PCV7 in 2005, rates of PCV7 serotype and all-cause IPD in unvaccinated children declined 89.5% and 61.4%, respectively, to be similar to rates in vaccinated children. Among non-Aboriginal children, VEs for 3 doses were 94.2% (95%CI: 81.9-98.1) for PCV7 serotype-specific IPD, 85.6% (95%CI: 60.5-94.8) for PCV13-non-PCV7 serotype-specific IPD and 80.1% (95%CI: 59.4-90.3) for all-cause IPD. There were no statistically significant differences between the VEs for 3 doses and for 1 or 2 doses against PCV13 and PCV13-non-PCV7 serotype-specific IPD, or between Aboriginal and non-Aboriginal children.

CONCLUSION

Our population-based cohort study demonstrates that >90% coverage in the first year of a universal 3 + 0 PCV program provided high population-level protection, predominantly attributable to strong herd effects. The size of the cohort enabled calculation of robust dose-specific VE estimates for important population sub-groups relevant to vaccination policies internationally.

Factors influencing pre-stroke and post-stroke quality of life among stroke survivors in a lower middle-income country

Quality of life (QOL) reflects the individual's perception of the position within living contexts. This study was done to describe pre- and post-stroke QOLs of stroke survivors. A prospective longitudinal study was done among stroke survivors admitted to 13 hospitals in the western province of Sri Lanka. The calculated sample size was 260. The pre-stroke and post-discharge one-month QOL was gathered using short form-36 (SF-36) QOL tool. SF-36 includes questions on eight domains: general health, physical functioning, pain, role limitation due to physical problems, social functioning, vitality, role limitations due to emotional problems, and mental health. Univariate analysis was followed by determining the independent risk factors through multivariate analysis. The response rate was 81%. The disability was measured by the modified Rankin scale which ranges from 0 (no symptoms) to 6 (fatal outcome). The median (IQR) disability score was 4 (3 to 5). The post-discharge QOL scores were significantly lower than pre-stroke values (p < 0.05). With a higher pre-stroke QOL, younger age was significantly associated in six domains and higher income and better health infrastructure in two domains (p < 0.05). Six factors were determined to be independent risk factors for lower post-discharge QOL scores of SF-36: younger age (for general health and role limitation-physical domains), female gender (for physical functioning and pain domains), lower health infrastructure (for general health, vitality, and mental health domains), lower education (for pain domain), higher disability (for general health, physical functioning, vitality, social functioning, and mental health domains), and hypercholesterolemia (for role limitation-emotional domain). Stroke survivors have not regained their pre-stroke QOL at 1 month following the hospital discharge irrespective of income level and pre-stroke QOL. Higher pre- and post-stroke QOLs are associated with better statuses of social determinants of health.

Financial burden of survivors of medically-managed myocardial infarction and its association with selected social determinants and quality of life in a lower middle income country

Background

Burden from ischemic heart disease is rising in Sri Lanka due to the demographic and epidemiological transitions. Documented literature is scarce on quality of life, financial burden and its determinants in relation to myocardial infarction (MI). This study was done to describe the financial burden among the survivors of MI managed only with drugs (i.e. those who did not undergo Percutaneous Coronary Intervention or Coronary Artery Bypass Graft) and its association with selected social determinants (SDHs) and quality of life (QOL).

Methods

A cross sectional study was done among MI survivors in 13 hospitals in the premier province of Sri Lanka. Out of 336 participants recruited at hospital stay, 270 responded through a self-administered questionnaire at 1 month post discharge. Questionnaire included sections on financial burden, selected SDHs and on QOL measured by the EQ-5D-3 L QOL tool. Presence of financial burden was determined using an operational definition. Associations were tested with Mann–Whitney-U test, Chi square test and Spearman-correlation-coefficient at 5% significant level.

Results

Around 40% (n = 116) had to seek financial support for out-of-pocket expenditure. Nearly 5% (n = 6) of previously employed participants had lost their job. Of the employed respondents (n = 139, 51.5%), 29% (n = 85) had limited physical activity and 40% (n = 115) had limitations of employment time. Of the respondents, 15.4% had to apply for a loan, 7.8% had to sell a property, 19.1% had an income loss and 33.8% had to restrict usual expenses. Financial burden was not significantly associated with gender (p = 0.146), ethnicity (p = 0.068), highest education (p = 0.184) and area of residence (p = 0.369). Influence of income (p = 0.001), social support (p = 0.002) and the health infrastructure (p < 0.001) were significantly associated with the occurrence of a financial burden. In the group with a financial burden, the index score (p = 0.002) and VAS score (p < 0.001) of EQ-5D-3 L were significantly lower.

Conclusions

Financial burden is common among survivors of medically-managed occurring irrespective of the gender, ethnicity, education and the area. It is influenced significantly by the income, level of social support and the level of health infrastructure. The financial burden is influencing the post-discharge-1-month QOL.

Molecular epidemiology of Hepatitis C Virus (HCV) in liver disease patients in Sri Lanka

Background: Globally, hepatitis C virus (HCV) is an important cause of chronic liver disease. Genotypes of HCV are associated with different profiles of pathogenicity, infectivity, and antiviral therapy. The prevalence of HCV and distribution of HCV genotypes in Sri Lanka in comparison with the rest of Asia is not well known.Objective: The objective of the study was to investigate the presence of HCV and to genotype HCV in a group of Sri Lankan patients suspected to have liver disease.Methods: A total of 1933 samples were screened for HCV antibodies using ELISA and HCV RNA with RT-PCR methods. RNA positive samples were genotyped by type specific amplification and by DNA sequencing.Results: Out Of the 1933 liver disease patients tested 219 (11.33%) were detected to be positive for anti-HCV antibodies, out of which, 54 (24.66%) were positive for HCV RNA. Furthermore out of 49 positively tested patients, 24 (48.97%) were found to be categorised as HCV genotype 1.Conclusion: This result confirms previous observations that the contribution of HCV as a causative virus in liver disease patients is low in Sri Lanka. HCV genotype 1 was found to be the most predominant genotype in studied cohort of Sri Lankan liver disease patients. DOI: http://dx.doi.org/10.3126/ajms.v6i3.10741Asian Journal of Medical Sciences Vol.6(3) 2015 1-5

Mesotherapy for local fat reduction

Mesotherapy, which is the injection of substances locally into mesodermally derived subcutaneous tissue, developed from empirical observations of a French physician in the 1950s. Although popular in Europe for many medical purposes, it is used for local cosmetic fat reduction in the United States. This paper reviews manuscripts indexed in PubMed/MEDLINE under 'mesotherapy', which pertains to local fat reduction. The history of lipolytic mesotherapy, the physiology of body fat distribution, the mechanism of action of different lipolytic stimulators and their increased efficacy in combination are reviewed. Mesotherapy falls into two categories. Lipolytic mesotherapy using lipolytic stimulators requires more frequent treatments as the fat cells are not destroyed and can refill over time. Ablative mesotherapy destroys fat cells with a detergent, causes inflammation and scarring from the fat necrosis, but requires fewer treatments. The historic and empiric mixing of sodium channel blocking local anaesthetics in mesotherapy solutions inhibits the intended lipolysis. Major mesotherapy safety concerns include injection site infections from poor sterile technique. Cosmetic mesotherapy directs the area from which fat is lost to improve self-image. Studies were of relatively small number, many with limited sample sizes. Future research should be directed towards achieving a Food and Drug Administration indication rather than continuing expansion of off-label use.

A preliminary study of the hospital-admitted older patients in a Sri Lankan tertiary care hospital

OBJECTIVE

To provide reasons for admission, comorbidities, physical and psychosocial characteristics, and outcome of older patients admitted to hospital in Sri Lanka, and to assess adequacy of routine assessment.

DESIGN

Descriptive study.

SETTING

University Medical Unit, National Hospital of Sri Lanka during 10 weeks commencing August 2003.

PATIENTS

All > or = 65 years admitted to the unit, excluding transfers for specialised management and direct admissions by consultants or clinics; 75 men and 75 women.

MEASUREMENTS

Vision, hearing and speech, tests for tendency to fall, basic activities of daily living (BADL), mood and cognition, body mass index and waist circumference.

RESULTS

Seventy three per cent and 40% had cognitive dysfunction and depression., 20% required assistance in > or = 5/9 BADL, 23% had unprovoked falls within past year, and 57% had a tendency to fall, 34% had < or =6/60 vision.

CONCLUSIONS

Falls, depression, cognitive dysfunction and severe visual impairment were present in substantial proportions, unidentified by routine assessment of older patients.

Contracts to devolve health services in fragile states and developing countries: do ethics matter?

Fragile states and developing countries increasingly contract out health services to non-state providers (NSPs) (such as non-governmental organisations, voluntary sector and private sector). The paper identifies ethical issues when contracts involve devolution of health services to NSPs and proposes procedures to prevent or resolve these ethical dilemmas. Ethical issues were identified by examining processes of contracting out. Health needs could be used to select areas to be contracted out and to identify service needs. Health needs comprise "disease-burden-related needs", "health-service needs", and "urgency of health-service needs". The mix of services should include an analysis of cost-effectiveness. NSPs should be selected fairly, without bias, and conflicts of interest during their work must be avoided. The population's views must be respected and accountability structures established. Devolved health services should ensure equity of access to healthcare. The services ought to be sustainable and evaluated objectively. Of these issues, conflicts of interest among NSPs and sustainability of health services have not attracted attention in the literature on ethics of health policy. Fair procedures could address these ethical issues-for example, public consultation on issues; decisions based on the public consultation and made on evidence; principles of decisions stated and reasonable; decisions given adequate publicity; a mechanism established to challenge decisions; assurance that mechanisms meet the above conditions; and regular review of the policies. These procedures are complemented by improving self-governance of NSPs, countries' development of guidelines for devolving health services, and measures to educate the public of the client countries on these issues.

Two Adults With Hypertriglyceridemia: How should one manage these persons?(#)

The paper discusses the management of two individuals with asymptomatic hypertriglyceredemia, a common problem faces by Family Physicians in Malaysia. In such instances it is advisable to exclude an underlying disorder (e.g. metabolic syndrome) and take a pragmatic approach.

Aspergillus meningitis following spinal anaesthesia for caesarean section in Colombo, Sri Lanka

We report six cases of Aspergillus meningitis after spinal anaesthesia for caesarean section administered in June and July 2005. Three patients died before a fungal infection was confirmed at the first post-mortem examination in August. Thereafter anti-fungal therapy was successful in saving the lives of the other three patients. Some syringes and spinal needles supplied to the hospitals concerned were found to be contaminated with Aspergillus fumigatus. Investigators found that medical supply storage facilities were substandard following the influx of donations after the tsunami of December 2004.

An outbreak of Aspergillus meningitis following spinal anaesthesia for caesarean section in Sri Lanka: a post-tsunami effect?

An outbreak of Aspergillus fumigatus meningitis occurred in 5 women following spinal anaesthesia, performed between 21 June and 17 July 2005 for caesarean section, in Colombo, Sri Lanka. The patients' median age was 27 years. Different teams in 2 maternity hospitals gave spinal anaesthesia. Mean incubation period was 11.2 days. Fever, headache and nuchal rigidity were common presentations. Remittent fever continued despite broad-spectrum intravenous antibiotics. Papilloedema, lateral rectus palsy, cerebral infarction and haemorrhage developed later. Three patients died. Cerebrospinal fluid pleocytosis with low glucose yielded negative PCR for fungi. Fungal cultures subsequently grew Aspergillus fumigatus. A post-mortem of the first patient confirmed Aspergillus meningitis, followed by treatment with amphotericin B and voriconazole, that saved the lives of others. Visual and hearing impairment in one and complete recovery in the other were observed a year after treatment. Examination of unused plastic syringes, needles, cannulae, and ampoules of anaesthetic agents confirmed that 43 syringes from three different manufactures were contaminated with Aspergillus fumigatus. The stores for drugs and devices of the Ministry of Health were examined and found to be full of tsunami donations, while regular procurements of the Ministry were kept in a poorly maintained humid warehouse. Inadequate space for tsunami donations was identified as the most plausible explanation for sub-optimal storage. Withdrawal and incineration of all unused syringes controlled the outbreak. The survival of those aggressively treated for Aspergillus meningitis suggests in hindsight that the availability of diagnostic tests and specific treatment, and early recognition of the outbreak could have saved the lives of victims who died. Early life-threatening side-effects and permanent long term sequelae of antifungal medication stress the need to be cautious with empirical treatment in immuno-competent low-risk individuals.

Oscillations of the snail genes in the presomitic mesoderm coordinate segmental patterning and morphogenesis in vertebrate somitogenesis

The segmented body plan of vertebrate embryos arises through segmentation of the paraxial mesoderm to form somites. The tight temporal and spatial control underlying this process of somitogenesis is regulated by the segmentation clock and the FGF signaling wavefront. Here, we report the cyclic mRNA expression of Snail 1 and Snail 2 in the mouse and chick presomitic mesoderm (PSM), respectively. Whereas Snail genes' oscillations are independent of NOTCH signaling, we show that they require WNT and FGF signaling. Overexpressing Snail 2 in the chick embryo prevents cyclic Lfng and Meso 1 expression in the PSM and disrupts somite formation. Moreover, cells mis-expressing Snail 2 fail to express Paraxis, remain mesenchymal, and are thereby inhibited from undergoing the epithelialization event that culminates in the formation of the epithelial somite. Thus, Snail genes define a class of cyclic genes that coordinate segmentation and PSM morphogenesis.

PTEN maintains haematopoietic stem cells and acts in lineage choice and leukaemia prevention

Haematopoietic stem cells (HSCs) must achieve a balance between quiescence and activation that fulfils immediate demands for haematopoiesis without compromising long-term stem cell maintenance, yet little is known about the molecular events governing this balance. Phosphatase and tensin homologue (PTEN) functions as a negative regulator of the phosphatidylinositol-3-OH kinase (PI(3)K)-Akt pathway, which has crucial roles in cell proliferation, survival, differentiation and migration. Here we show that inactivation of PTEN in bone marrow HSCs causes their short-term expansion, but long-term decline, primarily owing to an enhanced level of HSC activation. PTEN-deficient HSCs engraft normally in recipient mice, but have an impaired ability to sustain haematopoietic reconstitution, reflecting the dysregulation of their cell cycle and decreased retention in the bone marrow niche. Mice with PTEN-mutant bone marrow also have an increased representation of myeloid and T-lymphoid lineages and develop myeloproliferative disorder (MPD). Notably, the cell populations that expand in PTEN mutants match those that become dominant in the acute myeloid/lymphoid leukaemia that develops in the later stages of MPD. Thus, PTEN has essential roles in restricting the activation of HSCs, in lineage fate determination, and in the prevention of leukaemogenesis.

Study of dirofilariasis in a selected area in the Western Province

INTRODUCTION

Human dirofilariasis is a zoonotic infection caused by the filarial worm, Dirofilaria (Nochtiella) repens, whose primary host is the dog. This infection is on the increase over the past decade in Sri Lanka and the prevalence of canine dirofilariasis in the country is also believed to be high. We present here a study on public awareness of dirofilariasis and the prevalence of this infection in dogs in Negombo, an urban area that has a high domestic canine population.

OBJECTIVE

To assess the awareness of dirofilariasis infection among residents and study the prevalence of this infection in domestic dogs in Negombo.

DESIGN

Prospective study.

SETTING

Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka.

METHODS

A descriptive cross-sectional study within the city of Negombo during September and November 2003 using a pre-tested, interviewer-administered questionnaire with cluster sampling was done. Two hundred seventy adults, including 132 dog owners, were included in the study. Data analysis was done using the Epilnfo programme. The prevalence of canine dirofilariasis was studied in a group of 65 dogs over the age of 1 year. They were selected by cluster sampling with random choice of the streets within the study area. Stained thick blood films, made following an earlobe-prick at any time during the day, were microscopically examined for the presence of microfilariae.

RESULTS

Forty nine of the respondents (18%) were aware of the existence of canine dirofilariasis while human dirofilariasis was known only to 6%. Awareness was related to the level of education. Knowledge of canine filariasis was better among pet owners (32/132) when compared to others (18/138; p < 0.05). Veterinary surgeons were acknowledged as the source of information by 38% of those who were aware of the disease. Forty five per cent (n = 29) of the dogs screened were positive for microfilariae. Out of these 18 and two dogs were infected with D repens. and B. ceylonensis, respectively, while nine others were co-infected with the two parasites.

CONCLUSIONS

The knowledge of dirofilariasis is extremely poor in the study area. The high prevalence of filarial infections in dogs highlights the importance of improving the public awareness of this disease, especially among the dog owners. Proper management of this condition in dogs-the reservoirs of infection for human dirofilariasis, is important for the control of this zoonotic infection.

Energetics, stability, and prediction of transmembrane helices

We show that the peptide backbone of an alpha-helix places a severe thermodynamic constraint on transmembrane (TM) stability. Neglect of this constraint by commonly used hydrophobicity scales underlies the notorious uncertainty of TM helix prediction by sliding-window hydropathy plots of membrane protein (MP) amino acid sequences. We find that an experiment-based whole-residue hydropathy scale (WW scale), which includes the backbone constraint, identifies TM helices of membrane proteins with an accuracy greater than 99 %. Furthermore, it correctly predicts the minimum hydrophobicity required for stable single-helix TM insertion observed in Escherichia coli. In order to improve membrane protein topology prediction further, we introduce the augmented WW (aWW) scale, which accounts for the energetics of salt-bridge formation. An important issue for genomic analysis is the ability of the hydropathy plot method to distinguish membrane from soluble proteins. We find that the method falsely predicts 17 to 43 % of a set of soluble proteins to be MPs, depending upon the hydropathy scale used.

MPtopo: A database of membrane protein topology

The reliability of the transmembrane (TM) sequence assignments for membrane proteins (MPs) in standard sequence databases is uncertain because the vast majority are based on hydropathy plots. A database of MPs with dependable assignments is necessary for developing new computational tools for the prediction of MP structure. We have therefore created MPtopo, a database of MPs whose topologies have been verified experimentally by means of crystallography, gene fusion, and other methods. Tests using MPtopo strongly validated four existing MP topology-prediction algorithms. MPtopo is freely available over the internet and can be queried by means of an SQL-based search engine.

How to measure and analyze tryptophan fluorescence in membranes properly, and why bother?

Tryptophan fluorescence is a powerful tool for studying protein structure and function, especially membrane-active proteins and peptides. It is arguably the most frequently used tool for examining the interactions of proteins and peptides with vesicular unilamellar model membranes. However, high light scattering associated with vesicular membrane systems presents special challenges. Because of their reduced light scattering compared to large unilamellar vesicles (LUV), small unilamellar vesicles (SUV) produced by sonication are widely used membrane models. Unfortunately, SUV, unlike LUV, are metastable and consequently unsuitable for equilibrium thermodynamic measurements. We present simple and easily implemented experimental procedures for the accurate determination of tryptophan (Trp) fluorescence in either LUV or SUV. Specifically, we show that Trp spectra can be obtained in the presence of up to 6 mM LUV that are virtually identical to spectra obtained in buffer alone, which obviates the use of SUV. We show how the widths and peak positions of such spectra can be used to evaluate the heterogeneity of the membrane conformation and penetration of peptides. Finally, we show how to use a reference fluorophore for the correction of intensity measurements so that the energetics of peptide partitioning into membranes can be accurately determined.

The secretory carrier membrane protein family: structure and membrane topology

Secretory carrier membrane proteins (SCAMPs) are integral membrane proteins found in secretory and endocytic carriers implicated to function in membrane trafficking. Using expressed sequence tag database and library screens and DNA sequencing, we have characterized several new SCAMPs spanning the plant and animal kingdoms and have defined a broadly conserved protein family. No obvious fungal homologue has been identified, however. We have found that SCAMPs share several structural motifs. These include NPF repeats, a leucine heptad repeat enriched in charged residues, and a proline-rich SH3-like and/or WW domain-binding site in the N-terminal domain, which is followed by a membrane core containing four putative transmembrane spans and three amphiphilic segments that are the most highly conserved structural elements. All SCAMPs are 32-38 kDa except mammalian SCAMP4, which is approximately 25 kDa and lacks most of the N-terminal hydrophilic domain of other SCAMPs. SCAMP4 is authentic as determined by Northern and Western blotting, suggesting that this portion of the larger SCAMPs encodes the functional domain. Focusing on SCAMP1, we have characterized its structure further by limited proteolysis and Western blotting with the use of isolated secretory granules as a uniformly oriented source of antigen and by topology mapping through expression of alkaline phosphatase gene fusions in Escherichia coli. Results show that SCAMP1 is degraded sequentially from the N terminus and then the C terminus, yielding an approximately 20-kDa membrane core that contains four transmembrane spans. Using synthetic peptides corresponding to the three conserved amphiphilic segments of the membrane core, we have demonstrated their binding to phospholipid membranes and shown by circular dichroism spectroscopy that the central amphiphilic segment linking transmembrane spans 2 and 3 is alpha-helical. In the intact protein, these segments are likely to reside in the cytoplasm-facing membrane interface. The current model of SCAMP1 suggests that the N and C termini form the cytoplasmic surface of the protein overlying a membrane core, which contains a functional domain located at the cytoplasmic interface with little exposure of the protein on the ectodomain.

Structural features that modulate the transmembrane migration of a hydrophobic peptide in lipid vesicles

Two approaches employing nuclear magnetic resonance (NMR) were used to investigate the transmembrane migration rate of the C-terminal end of native alamethicin and a more hydrophobic analog called L1. Native alamethicin exhibits a very slow transmembrane migration rate when bound to phosphatidylcholine vesicles, which is no greater than 1 x 10(-4) min(-1). This rate is much slower than expected, based on the hydrophobic partition energies of the amino acid side chains and the backbone of the exposed C-terminal end of alamethicin. The alamethicin analog L1 exhibits crossing rates that are at least 1000 times faster than that of native alamethicin. A comparison of the equilibrium positions of these two peptides shows that L1 sits approximately 3-4 A deeper in the membrane than does native alamethicin (Barranger-Mathys and Cafiso. 1996. Biochemistry. 35:489). The slow rate of alamethicin crossing can be explained if the peptide helix is irregular at its C-terminus and hydrogen bonded to solvent or lipid. We postulate that L1 does not experience as large a barrier to transport because its C-terminus is already buried within the membrane interface. This difference is most easily explained by conformational differences between L1 and alamethicin rather than differences in hydrophobicity. The results obtained here demonstrate that side-chain hydrophobicity alone cannot account for the energy barriers to peptide and protein transport across membranes.