Comparison of left fourth and fifth intercostal space thoracotomy for open-chest cardiopulmonary resuscitation in dogs

OBJECTIVE

To determine whether ease of access to thoracic structures for performing open-chest cardiopulmonary resuscitation (OC-CPR) differed between fourth and fifth intercostal space (ICS) left lateral thoracotomies in dogs, and to determine if "shingling" improved access for OC-CPR manipulations.

DESIGN

Prospective single-blinded study.

SETTING

Laboratory.

ANIMALS

Twelve mixed breed canine cadavers weighing approximately 20 kg.

INTERVENTIONS

Left lateral thoracotomies were performed at the 4th ICS (n = 6) or 5th ICS (n = 6). Shingling at the 4th or 5th ICS, as applicable, was performed after initial data collection and outcomes were reassessed.

MEASUREMENTS AND MAIN RESULTS

Three evaluators blinded to the surgical approach scored the following parameters on a 0 to 10 scale (0 = easiest, 10 = most difficult): ease of access of the phrenicopericardial ligament, ease of pericardial incision, ease of appropriate hand position, ease of aortic access, ease of Rumel tourniquet application, and ease of proper placement of defibrillation paddles. Objective measurements (time to completion or number of attempts) were made for all but ease of pericardial incision and ease of appropriate hand position. Outcomes were reassessed after shingling. The 5th ICS was superior for ease of aortic access (P = 0.042), time to visualization of aorta (P = 0.009), and ease of application of a Rumel tourniquet (P = 0.019). When comparing scores pre- and post-shingling, shingling improved time to visualization of the aorta (P < 0.001), time to placement of Rumel tourniquet (P < 0.001), ease of paddle placement (P = 0.017), and time to paddle placement (P < 0.001).

CONCLUSIONS

Either 4th or 5th ICS thoracotomy may provide adequate access to intrathoracic structures pertinent to performing OC-CPR in dogs weighing approximately 20 kg, but 5th ICS was preferred for most manipulations, and shingling improved access for most of the measured parameters.

Implementing electronic data capture at a well-established health and demographic surveillance site in rural northern Malawi

This article aims to assess multiple issues of resources, staffing, local opinion, data quality, cost, and security while transitioning to electronic data collection (EDC) at a long-running community research site in northern Malawi. Levels of missing and error fields, delay from data collection to availability, and average number of interviews per day were compared between EDC and paper in a complex, repeated annual household survey. Three focus groups with field and data staff with experience using both methods, and in-depth interviews with participants were carried out. Cost for each method were estimated and compared. Missing data was more common on paper questionnaires than on EDC, and a similar number were carried out per day. Fieldworkers generally preferred EDC, but data staff feared for their employment. Most respondents had no strong preference for a method. The cost of the paper system was estimated to be higher than using EDC. The existing infrastructure and technical expertise could be adapted to using EDC, but changes have an impact on data processing jobs as fewer, and better qualified staff are required. EDC is cost-effective, and, for a long-running site, may offer further savings, as devices can be used in multiple studies and perform several other functions. EDC is accepted by fieldworkers and respondents, has good levels of quality and timeliness, and security can be maintained. EDC is well-suited for use in a well-established research site using and developing existing infrastructure and expertise.

Glycated haemoglobin A1c (HbA1c) for detection of diabetes mellitus and impaired fasting glucose in Malawi: a diagnostic accuracy study

OBJECTIVES

To examine the accuracy of glycated haemoglobin A_1c (HbA_1c) in detecting type 2 diabetes and impaired fasting glucose among adults living in Malawi.

DESIGN

A diagnostic validation study of HbA_1c. Fasting plasma glucose (FPG) ≥7.0 mmol/L was the reference standard for type 2 diabetes, and FPG between 6.1 and 6.9 mmol/L as impaired fasting glucose.

PARTICIPANTS

3645 adults (of whom 63% were women) recruited from two demographic surveillance study sites in urban and rural Malawi. This analysis excluded those who had a previous diagnosis of diabetes or had history of taking diabetes medication.

RESULTS

HbA_1c demonstrated excellent validity to detect FPG-defined diabetes, with an area under the receiver operating characteristic (AUROC) curve of 0.92 (95% CI 0.90 to 0.94). At HbA_1c ≥6.5% (140 mg/dL), sensitivity was 78.7% and specificity was 94.0%. Subgroup AUROCs ranged from 0.86 for participants with anaemia to 0.94 for participants in urban Malawi. There were clinical and metabolic differences between participants with true diabetes versus false positives when HbA_1c was ≥6.5% (140 mg/dL).

CONCLUSIONS

The findings from this study provide justification to use HbA_1c to detect type 2 diabetes. As HbA_1c testing is substantially less burdensome to patients than either FPG testing or oral glucose tolerance testing, it represents a useful option for expanding access to diabetes care in sub-Saharan Africa.

Prevalence of obesity, hypertension, and diabetes, and cascade of care in sub-Saharan Africa: a cross-sectional, population-based study in rural and urban Malawi

BACKGROUND

Sub-Saharan Africa is in rapid demographic transition, and non-communicable diseases are increasingly important causes of morbidity and mortality. We investigated the burden of diabetes, overweight and obesity, hypertension, and multimorbidity, their treatment, and their associations with lifestyle and other factors in Malawi, a very poor country with a predominantly rural-but rapidly growing urban-population, to identify high-risk populations and inform appropriate interventions.

METHODS

In this cross-sectional, population-based study, we enrolled all adults (≥18 years) residing in two defined geographical areas within Karonga District and Lilongwe city. All adults self-defining as usually resident in the study areas were eligible, and recruited at household level. Participants were interviewed, had anthropometry and blood pressure measured, and had fasting blood samples collected. The study outcomes were prevalence estimates and risk ratios for diabetes (defined as fasting blood glucose of at least 7·0 mmol/L or self-report of a previous diagnosis of diabetes), hypertension (systolic blood pressure of at least 140 mm Hg, diastolic blood pressure of at least 90 mm Hg, or self-report of current antihypertensive medication), overweight (BMI of 25·0-29·9 kg/m2) and obesity (BMI of 30·0 kg/m2 or more), and multimorbidity (two or more of the above conditions) by location-specific (urban vs rural), age-specific, and sex-specific groups, calculated using negative binomial regression. We used χ2 likelihood ratio tests to assess heterogeneity by age, location, and sex.

FINDINGS

Between May 16, 2013, and Feb 8, 2016, we enrolled 15 013 (62%) of 24 367 eligible urban adults in Lilongwe and 13 878 (88%) of 15 806 eligible rural adults in Karonga District. Overweight and obesity, hypertension, and diabetes were highly prevalent, more so in urban residents, the less poor, and better educated than in rural, the poorest, and least educated participants. 18% of urban men (961 of 5211 participants) and 44% (4115 of 9282) of urban women, and 9% (521 of 5834) of rural men and 27% (2038 of 7497) of rural women were overweight or obese; 16% (859 of 5212), 14% (1349 of 9793), 13% (787 of 5847), and 14% (1101 of 8025) had hypertension; and 3% (133 of 3928), 3% (225 of 7867), 2% (84 of 5004), and 2% (124 of 7116) had diabetes, respectively. Of 566 participants with diabetes, 233 (41%) were undiagnosed, and of 4096 participants with hypertension, 2388 (58%) were undiagnosed. Fewer than half the participants on medication for diabetes or hypertension had well controlled diabetes (84 [41%] of 207 participants) or blood pressure (440 [37%] of 1183 participants). Multimorbidity was highest in urban women (n=519, 7%).

INTERPRETATION

Overweight and obesity, hypertension, and diabetes are highly prevalent in urban and rural Malawi, yet many patients are undiagnosed and management is limited. Local-evidence-informed multisectoral, innovative, and targeted interventions are needed urgently to manage the already high burden.

FUNDING

Wellcome Trust.

Hypertension and diabetes in Africa: design and implementation of a large population-based study of burden and risk factors in rural and urban Malawi

Background

The emerging burden of cardiovascular disease and diabetes in sub-Saharan Africa threatens the gains made in health by the major international effort to combat infectious diseases. There are few data on distribution of risk factors and outcomes in the region to inform an effective public health response. A comprehensive research programme is being developed aimed at accurately documenting the burden and drivers of NCDs in urban and rural Malawi; to design and test intervention strategies. The programme includes population surveys of all people aged 18 years and above, linking individuals with newly diagnosed hypertension and diabetes to healthcare and supporting clinical services. The successes, challenges and lessons learnt from the programme to date are discussed.

Results

Over 20,000 adults have been recruited in rural Karonga and urban Lilongwe. The urban population is significantly younger and wealthier than the rural population. Employed urban individuals, particularly males, give particular recruitment challenges; male participation rates were 80.3 % in the rural population and 43.6 % in urban, whilst female rates were 93.6 and 75.6 %, respectively. The study is generating high quality data on hypertension, diabetes, lipid abnormalities and risk factors.

Conclusions

It is feasible to develop large scale studies that can reliably inform the public health approach to diabetes, cardiovascular disease and other NCDs in Sub-Saharan Africa. It is essential for studies to capture both rural and urban populations to address disparities in risk factors, including age structure. Innovative approaches are needed to address the specific challenge of recruiting employed urban males.

Using patient-held records to evaluate contraceptive use in Malawi

Objective

To investigate a method of using patient-held records to collect contraception data in Malawi, that could be used to explore contraceptive discontinuation and method switching.

Methods

In 2012, all 7393 women aged 15 to 49 years living in the area covered by the Karonga demographic surveillance site were offered a family planning card, which was attached to the woman’s health passport – a patient-held medical record. Health-care providers were trained to use the cards to record details of contraception given to women. During the study, providers underwent refresher training sessions and received motivational text messages to improve data completeness. After one year, the family planning cards were collected for analysis.

Findings

Of the 7393 eligible women, 6861 (92.8%) received a family planning card and 4678 (63.3%) returned it after one year. Details of 87.3% (2725/3122) of contacts between health-care providers and the women had been recorded by health-care providers on either family planning cards or health passports. Lower-level health-care providers were more diligent at recording data on the family planning cards than higher-level providers.

Conclusion

The use of family planning cards was an effective way of recording details of contraception provided by family planning providers. The involvement of health-care providers was key to the success of this approach. Data collected in this way should prove helpful in producing accurate estimates of method switching and the continuity of contraceptive use by women.

Maternal HIV status associated with under-five mortality in rural Northern Malawi: a prospective cohort study

BACKGROUND

Under-five mortality is decreasing but with little change in neonatal mortality rates. We examined the effect of maternal HIV status on under-five mortality and cause of death since widespread availability of antiretroviral therapy in rural Malawi.

METHODS

Children born in 2006-2011 in the Karonga demographic surveillance area were included. Maternal HIV status was available from HIV serosurveys. Age-specific mortality rate ratios for children born to HIV-positive and HIV-negative mothers were obtained by fitting a Poisson model accounting for child clustering by mother and adjusting for potential confounders. Cause of death was ascertained by verbal autopsy.

FINDINGS

There were 352 deaths among 6913 under-five singleton children followed for 20,754 person-years (py), giving a mortality rate of 17.0/1000 py overall, 218/1000 py (16.5/1000 live births) in neonates, 20/1000 py (17.4/1000 live births) in postneonatal infants, and 8/1000 py in 1-4 years old. Comparing those born to HIV-positive and HIV-negative mothers, the rate ratio adjusted for child age, sex, maternal age, parity, and drinking water source was 1.5 (95% confidence interval [CI]: 0.6 to 3.7) in neonates, 11.5 (95% CI: 7.2 to 18.5) in postneonatal infants, and 4.6 (95% CI: 2.7 to 7.9) in 1-4 years old. Birth injury/asphyxia, neonatal sepsis, and prematurity contributed >70% of neonatal deaths, whereas acute infections, malaria, diarrhea, and pneumonia accounted for most deaths in older children.

CONCLUSIONS

Maternal HIV status had little effect on neonatal mortality but was associated with much higher mortality in the postneonatal period and among older children. Greater attention to HIV care in pregnant women and mothers should help improve child survival, but broader interventions are needed to reduce neonatal mortality.

Ultrasonic enhancement of battery diffusion

It has been demonstrated that sonic energy can be harnessed to enhance convection in Galvanic cells during cyclic voltammetry; however, the practical value of this approach is limited due to the lack of open volumes for convection patterns to develop in most batteries. This study evaluates the ability of ultrasonic waves to enhance diffusion in membrane separators commonly used in sandwich-architecture batteries. Studies include the measuring of open-circuit performance curves to interpret performances in terms of reductions in concentration overpotentials. The use of a 40 kHz sonicator bath can consistently increase the voltage of the battery and reduce overpotential losses up to 30%. This work demonstrates and quantifies battery enhancement due to enhanced diffusion made possible with ultrasonic energy.

Monitoring the impact of decentralised chronic care services on patient travel time in rural Africa--methods and results in Northern Malawi

Background

Decentralised health services form a key part of chronic care strategies in resource-limited settings by reducing the distance between patient and clinic and thereby the time and costs involved in travelling. However, few tools exist to evaluate the impact of decentralisation on patient travel time or what proportion of patients attend their nearest clinic. Here we develop methods to monitor changes in travel time, using data from the antiretroviral therapy (ART) roll-out in a rural district in North Malawi.

Methods

Clinic position was combined with GPS information on the home village of patients accessing ART services in Karonga District (North Malawi) between July 2005 and July 2009. Potential travel time was estimated as the travel time for an individual attending their nearest clinic, and estimated actual travel time as the time to the clinic attended. This allowed us to calculate changes in potential and actual travel time as new clinics opened and track the proportion and origin of patients not accessing their nearest clinic.

Results

The model showed how the opening of further ART clinics in Karonga District reduced median potential travel time from 83 to 43 minutes, and median actual travel time fell from 83 to 47 minutes. The proportion of patients not attending their nearest clinic increased from 6% when two clinics were open, to 12% with four open.

Discussion

Integrating GPS information with patient data shows the impact of decentralisation on travel time and clinic choice to inform policy and research questions. In our case study, travel time decreased, accompanied by an increased uptake of services. However, the model also identified an increasing proportion of ART patients did not attend their nearest clinic.

Profile: the Karonga Health and Demographic Surveillance System

The Karonga Health and Demographic Surveillance System (Karonga HDSS) in northern Malawi currently has a population of more than 35 000 individuals under continuous demographic surveillance since completion of a baseline census (2002–2004). The surveillance system collects data on vital events and migration for individuals and for households. It also provides data on cause-specific mortality obtained by verbal autopsy for all age groups, and estimates rates of disease for specific presentations via linkage to clinical facility data. The Karonga HDSS provides a structure for surveys of socio-economic status, HIV sero-prevalence and incidence, sexual behaviour, fertility intentions and a sampling frame for other studies, as well as evaluating the impact of interventions, such as antiretroviral therapy and vaccination programmes. Uniquely, it relies on a network of village informants to report vital events and household moves, and furthermore is linked to an archive of biological samples and data from population surveys and other studies dating back three decades.

BCG vaccination induces different cytokine profiles following infant BCG vaccination in the UK and Malawi

Background. BCG vaccination of infants is thought to provide good protection in all settings. This study investigated whether Malawian infants made weaker responses across a cytokine panel after BCG vaccination, compared with UK infants.

Methods. Diluted whole-blood samples were cultured with Mycobacterium tuberculosis purified protein derivative for 6 days from BCG-vaccinated infants 3 months (n = 40 Malawi, 28 UK) and 12 months (n = 34 Malawi, 26 UK) after vaccination, and also from UK unvaccinated infants (n = 9 at 3 months, n = 10 at 12 months). Forty-two cytokines were measured in supernatants using a multiplex bead array assay. Principal component analysis was used to summarize the overall patterns in cytokine responses.

Results. We found differences in median responses in 27 of the 42 cytokines: 7 higher in the UK and 20 higher in Malawi. The cytokines with higher responses in the UK were all T helper 1 related. The cytokines with higher responses in Malawi included innate proinflammatory cytokines, regulatory cytokines, interleukin 17, T helper 2 cytokines, chemokines, and growth factors. Principal component analysis separated the BCG-vaccinated infants from Malawi from the UK vaccinated infants and from the unvaccinated infants.

Conclusions. Malawian infants make cytokine responses following BCG vaccination, but the cytokine profile is different from that in the UK. The different biosignatures following BCG vaccination in the 2 settings may indicate variability in the protective efficacy of infant BCG vaccination.

BCG vaccination: a role for vitamin D?

Background

BCG vaccination is administered in infancy in most countries with the aim of providing protection against tuberculosis. There is increasing interest in the role of vitamin D in immunity to tuberculosis. This study objective was to determine if there was an association between circulating 25(OH)D concentrations and BCG vaccination status and cytokine responses following BCG vaccination in infants.

Methods

Blood samples were collected from UK infants who were vaccinated with BCG at 3 (n = 47) and 12 (n = 37) months post BCG vaccination. These two time-points are denoted as time-point 1 and time-point 2. Two blood samples were also collected from age-matched unvaccinated infants (n = 32 and 28 respectively), as a control group. Plasma vitamin D concentrations (25(OH)D) were measured by radio-immunoassay. The cytokine IFNγ was measured in supernatants from diluted whole blood stimulated with M.tuberculosis (M.tb) PPD for 6 days.

Results

58% of infants had some level of hypovitaminosis (25(OH)D <30ng/ml) at time-point 1, and this increased to 97% 9 months later. BCG vaccinated infants were almost 6 times (CI: 1.8–18.6) more likely to have sufficient vitamin D concentrations than unvaccinated infants at time-point 1, and the association remained strong after controlling for season of blood collection, ethnic group and sex. Among vaccinees, there was also a strong inverse association between IFNγ response to M.tb PPD and vitamin D concentration, with infants with higher vitamin D concentrations having lower IFNγ responses.

Conclusions

Vitamin D may play an immuno-regulatory role following BCG vaccination. The increased vitamin D concentrations in BCG vaccinated infants could have important implications: vitamin D may play a role in immunity induced by BCG vaccination and may contribute to non-specific effects observed following BCG vaccination.

Population-level reduction in adult mortality after extension of free anti-retroviral therapy provision into rural areas in northern Malawi

Background

Four studies from sub-Saharan Africa have found a substantial population-level effect of ART provision on adult mortality. It is important to see if the impact changes with time since the start of treatment scale-up, and as treatment moves to smaller clinics.

Methods and Findings

During 2002-4 a demographic surveillance site (DSS) was established in Karonga district, northern Malawi. Information on births and deaths is collected monthly, with verbal autopsies conducted for all deaths; migrations are updated annually. We analysed mortality trends by comparing three time periods: pre-ART roll-out in the district (August 2002–June 2005), ART period 1 (July 2005–September 2006) when ART was available only in a town 70 km away, and ART period 2 (October 2006–September 2008), when ART was available at a clinic within the DSS area. HIV prevalence and ART uptake were estimated from a sero-survey conducted in 2007/2008. The all-cause mortality rate among 15–59 year olds was 10.2 per 1000 person-years in the pre-ART period (288 deaths/28285 person-years). It fell by 16% in ART period 1 and by 32% in ART period 2 (95% CI 18%–43%), compared with the pre-ART period. The AIDS mortality rate fell from 6.4 to 4.6 to 2.7 per 1000 person-years in the pre-ART period, period 1 and period 2 respectively (rate ratio for period 2 = 0.43, 95% CI 0.33–0.56). There was little change in non-AIDS mortality. Treatment coverage among individuals eligible to start ART was around 70% in 2008.

Conclusions

ART can have a dramatic effect on mortality in a resource-constrained setting in Africa, at least in the early years of treatment provision. Our findings support the decentralised delivery of ART from peripheral health centres with unsophisticated facilities. Continued funding to maintain and further scale-up treatment provision will bring large benefits in terms of saving lives.

Population differences in immune responses to Bacille Calmette-Guérin vaccination in infancy

Bacille Calmette-Guérin (BCG) vaccination induces a marked increase in the interferon (IFN)-gamma response to Mycobacterium tuberculosis purified protein derivative (Mtb PPD) in UK adolescents, but not in Malawian adolescents. We hypothesized that Mtb PPD-induced IFN-gamma after BCG vaccination would be similar in infants from these 2 countries. Infants were vaccinated with BCG during the first 3-13 weeks of life. Three months after BCG vaccination, 51 (100%) of 51 UK infants had an IFN-gamma response to Mtb PPD, compared to 41 (53%) of 78 of Malawian infants, in whom responses varied according to their season of birth. We conclude that population differences in immune responses after BCG vaccination are observed among infants, as well as among young adults.

The effect of bupivacaine and morphine in a coculture model of diarthrodial joints

PURPOSE

To perform a controlled laboratory study to evaluate the effect of bupivacaine and morphine on chondrocytes and synovium in a coculture model of diarthrodial joints.

METHODS

A proven coculture model that allows for the assessment of cartilage and synovium exists. The model allows for simulation of the diarthrodial joint in both health and disease by using culture media with or without the addition of interleukin-1. Effects of the presence of bupivacaine and morphine were evaluated by measuring media concentration of glycosamino glycans (GAG), nitric oxide (NO), and prostaglandin E(2) (PGE(2)), and tissue concentration of GAG, water, and collagen. Cell viability was determined through the use of confocal microscopy on days 1 and 2.

RESULTS

Cell viability 2 days after exposure to 0.5% bupivacaine was significantly less in the presence of bupivacaine than in the other groups, nearing a 100% decrease in viability. There was little effect of bupivacaine on cartilage water content or the tissue concentration of GAG and collagen. Morphine and bupivacaine both inhibited the expected rise in NO and PGE(2) when interleukin-1 was added to the media.

CONCLUSIONS

Continuous 0.5% bupivacaine exposure has a clear detrimental effect on chondrocytes in this in vitro study. Both bupivacaine and morphine appear to have anti-inflammatory effects. Continuous morphine exposure does not cause gross chondrotoxicity in vitro and presents itself as a potential alternative intra-articular analgesic.

CLINICAL RELEVANCE

Intra-articular bupivacaine infusion is an effective analgesic strategy and is frequently used in both office and outpatient surgical settings. This study provides evidence that the continued usage of postoperative bupivacaine continuous infusion pumps may have a detrimental effect on chondrocytes. Morphine has been shown to be an effective intra-articular analgesic, and its anti-inflammatory role seen in this study makes it a potential alternative to bupivacaine.

Comparison of IFN-gamma responses to mycobacterial antigens as markers of response to BCG vaccination

An increase in interferon-gamma (IFN-gamma) production to Mycobacterium tuberculosis purified protein derivative (Mtb PPD), as measured in the cultured diluted whole blood assay, is one indicator of a protective immune response to BCG vaccine. We have explored the potential for this assay to be improved by measuring IFN-gamma responses to more defined antigens of M. tuberculosis (short-term and mid-term culture filtrates, ESAT-6, 38 kDa), Mycobacterium bovis (MPB70), M. bovis BCG (Antigen 85) and Mycobacterium leprae (35 kDa), in UK teenagers before and 1 year after BCG vaccination (or no vaccination as controls). There was a significant increase in response to the culture filtrates post-vaccination, but this was no greater than that to Mtb PPD. Many teenagers responded to the purified antigens, in particular to Antigen 85, prior to vaccination, and BCG vaccination could only augment this pre-existing response to a limited extent; prior exposure to environmental mycobacteria can thus induce cross-reactive responses to antigens which complicate interpretation of in vitro assays of vaccine response. In contrast, ESAT-6 was recognised by only one teenager prior to vaccination, and, as expected, responses were not boosted by BCG. We therefore conclude that Mtb PPD is the antigen preparation of choice for assessing the immunogenicity of BCG vaccination.

Assessment and evaluation of contact as a risk factor for tuberculosis in rural Africa

SETTING

A rural district in Malawi.

OBJECTIVE

To determine the effect of inaccurate recall on estimates of the proportion of tuberculosis (TB) cases attributable to contact with identifiable prior cases.

DESIGN

Case-control study of laboratory-confirmed TB cases and community controls, comparing family, household and area contacts identified from a database of TB cases with those named at interview. Estimation of prior contact as a risk factor for TB and identified factors associated with being a named contact.

RESULTS

Ninety-five per cent of named contacts were known TB cases. The proportion of total identified contacts who were named at interview was 75%, and was similar for cases and controls. Cases were twice as likely as controls to identify prior contacts. Adding database information did not affect odds ratios, but increased the proportion of TB cases attributable to prior contact. Smear-positive, male and human immunodeficiency virus (HIV) negative TB patients were more likely to be named by subsequent cases. Identifiable recent contact with known smear-positive cases accounted for 12.5% of the TB burden.

CONCLUSIONS

Reporting of putative source contacts showed little evidence of recall bias and gave estimates of the relative risk of TB associated with identifiable contact. The lower likelihood of HIV-positive cases being named as contacts may reflect reduced infectiousness.

Persistence of the immune response induced by BCG vaccination

Background

Although BCG vaccination is recommended in most countries of the world, little is known of the persistence of BCG-induced immune responses. As novel TB vaccines may be given to boost the immunity induced by neonatal BCG vaccination, evidence concerning the persistence of the BCG vaccine-induced response would help inform decisions about when such boosting would be most effective.

Methods

A randomised control study of UK adolescents was carried out to investigate persistence of BCG immune responses. Adolescents were tested for interferon-gamma (IFN-γ) response to Mycobacterium tuberculosis purified protein derivative (M.tb PPD) in a whole blood assay before, 3 months, 12 months (n = 148) and 3 years (n = 19) after receiving teenage BCG vaccination or 14 years after receiving infant BCG vaccination (n = 16).

Results

A gradual reduction in magnitude of response was evident from 3 months to 1 year and from 1 year to 3 years following teenage vaccination, but responses 3 years after vaccination were still on average 6 times higher than before vaccination among vaccinees. Some individuals (11/86; 13%) failed to make a detectable antigen-specific response three months after vaccination, or lost the response after 1 (11/86; 13%) or 3 (3/19; 16%) years. IFN-γ response to Ag85 was measured in a subgroup of adolescents and appeared to be better maintained with no decline from 3 to 12 months. A smaller group of adolescents were tested 14 years after receiving infant BCG vaccination and 13/16 (81%) made a detectable IFN-γ response to M.tb PPD 14 years after infant vaccination as compared to 6/16 (38%) matched unvaccinated controls (p = 0.012); teenagers vaccinated in infancy were 19 times more likely to make an IFN-γ response of > 500 pg/ml than unvaccinated teenagers.

Conclusion

BCG vaccination in infancy and adolescence induces immunological memory to mycobacterial antigens that is still present and measurable for at least 14 years in the majority of vaccinees, although the magnitude of the peripheral blood response wanes from 3 months to 12 months and from 12 months to 3 years post vaccination. The data presented here suggest that because of such waning in the response there may be scope for boosting anti-tuberculous immunity in BCG vaccinated children anytime from 3 months post-vaccination. This supports the prime boost strategies being employed for some new TB vaccines currently under development.

The influence of previous exposure to environmental mycobacteria on the interferon-gamma response to bacille Calmette-Guérin vaccination in southern England and northern Malawi

We report a large study of the effect of BCG vaccination on the in vitro 6-day whole blood interferon-gamma (IFN-gamma) response to antigens from eight species of mycobacteria among schoolchildren in south-eastern England, where bacille Calmette-Guérin (BCG) vaccination is highly protective against pulmonary tuberculosis, and among young adults in northern Malawi, where BCG vaccination is not protective. In the UK children, BCG induced an appreciable increase in IFN-gamma response to antigens from most species of mycobacteria. The degree of change was linked to the relatedness of the species to Mycobacterium bovis BCG, and provides further evidence of the cross-reactivity of mycobacterial species in priming of the immune system. IFN-gamma responses to purified protein derivatives (PPDs) from M. tuberculosis and environmental mycobacteria were more prevalent in the Malawian than the UK group prior to vaccination; BCG vaccination increased the prevalence of responses to these PPDs in the UK group to a level similar to that in Malawi. There was no evidence that the vaccine-induced change in IFN-gamma response was dependent upon the magnitude of the initial response of the individual to environmental mycobacteria in the United Kingdom or in Malawi. These observations should assist the development and interpretation of human clinical trials of new vaccines against M. tuberculosis in areas of both low and high exposure to environmental mycobacteria.

Immunogenicity of Danish-SSI 1331 BCG vaccine in the UK: Comparison with Glaxo-Evans 1077 BCG vaccine

The immunogenicity and reactogenicity, in British schoolchildren, of the newly introduced Danish-SSI 1331 BCG vaccine was compared with that of the previously used Glaxo-Evans 1077 BCG vaccine. Interferon-gamma (IFN-gamma) response to M. tuberculosis purified protein derivative (M.tb PPD) in a 6-day whole blood assay and delayed type hypersensitivity (DTH) to tuberculin PPD were determined before and 1 year after receiving BCG or no vaccination. Scar size was measured 1 year after vaccination. There was no evidence of a difference in immunogenicity (IFN-gamma and DTH conversion rates) but evidence of lower reactogenicity (scar size) with Danish-SSI 1331 compared to Glaxo-Evans 1077 vaccines.

Side population/ABCG2-positive cells represent a heterogeneous group of haemopoietic cells: implications for the use of adult stem cells in transplantation and plasticity protocols

Murine side population (SP) cells may have an increased ability to engraft lethally irradiated mice and lack CD34 expression. Strategies using CD34 as a primary marker of haemopoietic stem cells may therefore result in the exclusion of a primitive stem cell population. The molecular basis for the murine SP phenotype has been attributed to the multidrug-resistance transporter ABCG2. This study aimed to investigate ABCG2 expression from a variety of human sources and investigate the relationship between ABCG2 expression, the SP phenotype, and expression of markers such as CD34 and CD133. SP cells were observed in different haemopoietic sources, but a significant increase in the number of SP cells was observed in PB following granulocyte colony-stimulating factor mobilisation. No direct correlation between the frequency of SP cells and the expression of ABCG2 was observed. SP cells were identified in both lineage-positive and lineage-negative population and ABCG2 expression was enriched in lineage-negative SP cells. Lineage-negative SP cells were devoid of CD34 expression but enriched for CD133. Subsequent analysis revealed that ABCG2 and CD133 are coexpressed. Together, these data suggest that the ABCG2 transporter is neither required nor responsible for the SP phenotpye in many human blood cells.

Interferon-gamma and skin test responses of schoolchildren in southeast England to purified protein derivatives from Mycobacterium tuberculosis and other species of mycobacteria

The immune responses of schoolchildren in southeast England to Mycobacterium tuberculosis and other species of mycobacteria were studied prior to vaccination with bacille Calmette-Guérin (BCG). Data are presented for tuberculin (Heaf) skin test and interferon-gamma (IFN-gamma) responses to M. tuberculosis purified protein derivative (PPD), and IFN-gamma responses to PPDs from eight other environmental mycobacteria, measured in 424 schoolchildren (13-15 years of age). Responses to M. tuberculosis PPD were detected in 27% of schoolchildren by in vitro IFN-gamma response and in 20% by the Heaf test. IFN-gamma responses were more prevalent to PPDs from species of mycobacteria other than M. tuberculosis, predominantly those of the MAIS complex and M. marinum (45-60% responders). Heaf test and IFN-gamma responses were associated (P<0.001) for M. tuberculosis, MAIS and M. marinum. These findings have implications for appropriate implementation of vaccination against tuberculosis.

Experimental inoculation of domestic cats (Felis domesticus) with Sarcocystis neurona or S. neurona-like merozoites

Sarcocystis neurona is the parasite most commonly associated with equine protozoal myeloencephalitis (EPM). Recently, cats (Felis domesticus) have been demonstrated to be an experimental intermediate host in the life cycle of S. neurona. This study was performed to determine if cats experimentally inoculated with culture-derived S. neurona merozoites develop tissue sarcocysts infectious to opossums (Didelphis virginiana), the definitive host of S. neurona. Four cats were inoculated with S. neurona or S. neurona-like merozoites and all developed antibodies reacting to S. neurona merozoite antigens, but tissue sarcocysts were detected in only two cats. Muscle tissues from the experimentally inoculated cats with and without detectable sarcocysts were fed to laboratory-reared opossums. Sporocysts were detected in gastrointestinal (GI) scrapings of one opossum fed experimentally infected feline tissues. The study results suggest that cats can develop tissue cysts following inoculation with culture-derived Sarcocystis sp. merozoites in which the particular isolate was originally derived from a naturally infected cat with tissue sarcocysts. This is in contrast to cats which did not develop tissue cysts when inoculated with S. neurona merozoites originally derived from a horse with EPM. These results indicate present biological differences between the culture-derived merozoites of two Sarcocystis isolates, Sn-UCD 1 and Sn-Mucat 2.

Polymorphisms in the Il12b gene affect structure and expression of IL-12 in NOD and other autoimmune-prone mouse strains

Interleukin (Il)-12 is a heterodimeric cytokine composed of 35 and 40 kD chains that plays a key role in the induction of Th1 cells, a T cell subset involved in many autoimmune diseases. We report here the cDNA sequence encoding the IL-12 p40 subunit from the autoimmune-prone non-obese diabetic (NOD) mouse, which spontaneously develops type 1 diabetes. Compared with the C57BL/6 sequence, there are two base changes that lead to amino acid replacements. Other autoimmune-prone strains, but not the diabetes-resistant NOR strain, share the same allele as NOD. We found both trans- and cis- allele-dependent effects on levels of basal and induced IL-12p40 expression. Furthermore, we show that one of these changes results in a structural change in the p40 molecule, as evidenced by the failure of a monoclonal antibody to bind NOD IL-12. These findings have implications for the predisposition to autoimmune responses in NOD and other autoimmune-prone mouse strains.

BCG-induced increase in interferon-gamma response to mycobacterial antigens and efficacy of BCG vaccination in Malawi and the UK: two randomised controlled studies

BACKGROUND

The efficacy of BCG vaccines against pulmonary tuberculosis varies between populations, showing no protection in Malawi but 50-80% protection in the UK. To investigate the mechanism underlying these differences, randomised controlled studies were set up to measure vaccine-induced immune responsiveness to mycobacterial antigens in both populations.

METHODS

483 adolescents and young adults in Malawi and 180 adolescents in the UK were tested for interferon-gamma (IFN-gamma) response to M tuberculosis purified protein derivative (PPD) in a whole blood assay, and for delayed type hypersensitivity (DTH) skin test response to tuberculin PPD, before and 1 year after receiving BCG (Glaxo 1077) vaccination or placebo or no vaccine.

FINDINGS

The percentages of the randomised individuals who showed IFN-gamma and DTH responses were higher in Malawi than in the UK pre-vaccination-ie, 61% (331/546) versus 22% (47/213) for IFN-gamma and 46% (236/517) versus 13% (27/211) for DTH. IFN-gamma responses increased more in the UK than in Malawi, with 83% (101/122) and 78% (251/321) respectively of the vaccinated groups responding, with similar distributions in the two populations 1 year post-vaccination. The DTH response increased following vaccination in both locations, but to a greater extent in the UK than Malawi. The IFN-gamma and DTH responses were strongly associated, except among vaccinees in Malawi.

INTERPRETATION

The magnitude of the BCG-attributable increase in IFN-gamma responsiveness to M tuberculosis PPD, from before to 1 year post-vaccination, correlates better with the known levels of protection induced by immunisation with BCG than does the absolute value of the IFN-gamma or DTH response after vaccination. It is likely that differential sensitisation due to exposure to environmental mycobacteria is the most important determinant of the observed differences in protection by BCG between populations.

Lymphatic filariasis in the Karonga district of northern Malawi: a prevalence survey

In Malawi, two main foci of lymphatic filariasis (LF) are known to exist: one in the south, in the Shire valley, and the other in the north, along the Songwe River, on the border with Tanzania. There have been no formal surveys in the Songwe area since the 1960s but an opportunity arose in 2000-2001 to map LF in this area, in the context of a leprosy survey that formed part of the follow-up of a large leprosy and tuberculosis vaccine trial. Overall 687 immunochromatographic (ICT) tests were carried out. Wuchereria bancrofti antigenaemia was found in > 25% of adults in each of the 12 villages sampled (four in the Songwe area and eight in the rest of the Karonga district), with village prevalences varying from 28%-58%. Of the 685 adult male residents of the Songwe area who were each given full-body clinical examinations, 80 (11.7%) were identified as cases of hydrocele. Lymphoedema was found in seven (1.0%) of these adult males and in 29 (3.7%) of the 769 adult female residents of the Songwe area who were also examined. Microfilariae were detected in 33 (30.8%) of the 107 thick smears of night-blood samples that were made from individuals with positive ICT cards. The W. bancrofti infection focus in Karonga district is therefore wider than was previously known. This has important implications for the implementation and eventual impact of LF-control activities in this area.

Improvement in quality of life for cancer patients treated with epoetin alfa

Anaemia is a common complication of cancer and cancer therapies, and fatigue is one of the most common symptoms of anaemia, disrupting functional performance and reducing overall quality of life. The positive effects of treating renal patients with recombinant human erythropoietin are well documented. This case report series details the specific effects of fatigue on individual patients with cancer and their way of life, and describes their significant improvement in lifestyle following the reversal of anaemia using recombinant human erythropoietin, epoetin alfa.

The effects of intravascular stents on vasomotion in porcine coronary arteries

Intravascular stents are being increasingly utilized in the treatment of atherosclerotic coronary artery disease, however little is known about the effects of stents on coronary vasomotion. The purpose of the present study was to compare the effects of a heparin treated tantalum stent and balloon injury on coronary artery vasorelaxation and vasoconstriction. Male miniswine underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. After two weeks, one artery was either balloon-injured again, or underwent implantation of a stent. Four weeks later, the coronary arteries were prepared for in vitro isometric ring studies. Vasodilator responses to bradykinin and A23187 calcium ionophore were significantly impaired in balloon-injured vessels. The bradykinin and A23187 responses in stented vessels showed significantly less vasorelaxation, compared to both balloon-injured and normal vessels. There were no significant differences between any of the groups in their vasodilator response to nitroprusside. Vasoconstrictor responses to acetylcholine were significantly greater in balloon-injured vessels, compared to normal vessels. Stented vessels, however, showed markedly less vasoconstriction to acetylcholine compared to both balloon-injured and normal vessels. The maximal KCI vasoconstrictor responses in balloon injured vessels and normal controls were not significantly different. However, the maximal KCI responses in stented vessels showed significantly less constriction compared to both balloon injured and normal vessels. In conclusion, the data demonstrated that coronary arteries implanted with a heparin treated tantalum stent were capable of vasomotor activity. Both conventional balloon angioplasty and stents resulted in impaired endothelium-dependent vasorelaxation. Endothelium-independent vasorelaxation, however, was not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

Restenosis following placement of an intracoronary heparin treated tantulum stent in the hyperlipidemic miniature swine model

Restenosis persists as an important factor limiting a favorable long term outcome following mechanical revascularization. The objective of the present study was to compare the effects of an intracoronary heparin treated tantalum prototype stent and balloon angioplasty on intimal hyperplasia, luminal diameter, and thrombosis in a porcine restenosis model. Male miniswine maintained on a high cholesterol diet and 325 mg aspirin per day underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. Two weeks later one artery was either balloon injured again or implanted with a stent. No additional anticoagulation following stent placement was given, however aspirin was continued throughout the study. At four weeks, the coronary arteries were harvested and prepared for histologic examination and blinded quantitative morphometric analysis. The prototype stent was successfully deployed in 10 coronary arteries. Histological examination at explant revealed no evidence for thrombus or platelet aggregation. The angiographic luminal diameter of stented vessels was not significantly different from the diameter measured prior to implantation. In contrast, the angiographic diameter of balloon injured vessels was significantly decreased (4.4 +/- 0.4 mm2, balloon injured, vs. 5.8 +/- 3.3 mm2, control; p < 0.05). Stented arteries showed significantly more intimal hyperplasia, compared to balloon injured vessels (2.99 +/- 0.58 mm2 intimal area, stented arteries vs. 0.38 +/- 0.15 mm2 intimal area, control arteries; p < 0.05). In conclusion, heparin treated tantalum wire prototype intracoronary stents were successfully deployed in swine coronary arteries with no evidence for thrombus formation. Despite a significant intimal response, luminal diameter was preserved in stented vessels. The data suggest that a heparin treated tantalum wire prototype intracoronary stent may be an effective method of coronary revascularization that results in the preservation of luminal diameter without thrombotic occlusion.