EQ-5D-5L: a value set for Romania

OBJECTIVE

We aimed to develop an EQ-5D-5L value set for Romania.

METHODS

In line with the EuroQoL standardized valuation protocol, computer-assisted interviews were conducted face-to-face in a representative sample in Romania (November 2018-November 2019). Valuation methods included composite time trade-off and discrete choice experiment tasks. Several models were tested, including models that accounted for data censoring, panel structure of the data, heteroscedasticity, conditional logit, and hybrid models. The final model was selected based on logical consistency, theoretical considerations, and use of all available data. We compared our value set with other value sets from Central and Eastern Europe region.

RESULTS

Data from 1493 respondents was used to estimate the value set. A censored hybrid model corrected for heteroscedasticity was selected to represent the value set. The highest decrements in utility were observed for the pain/discomfort dimension (0.375), followed by the mobility dimension (0.293). Health utilities ranged from 1.000 to - 0.323 and 1.3% of the values were negative. The model was corrected with survey weights to better reflect the representativeness of the sample, but the first two coefficients of the self-care dimension stopped being logically consistent. Differences were found between the Romanian, Hungarian and Polish EQ-5D-5L value sets. Good agreement was noted with the Romanian EQ-5D-3L value set, with a swap between pain/discomfort and mobility in ranking of dimensions.

CONCLUSION

A value set for EQ-5D-5L is now available for Romania. This will push one-step further the development of health technology assessment and encourage more health-related quality-of-life research to be conducted locally.

Impact of a social prescribing intervention in North East England on adults with type 2 diabetes: the SPRING_NE multimethod study

Background

Link worker social prescribing enables health-care professionals to address patients’ non-medical needs by linking patients into various services. Evidence for its effectiveness and how it is experienced by link workers and clients is lacking.

Objectives

To evaluate the impact and costs of a link worker social prescribing intervention on health and health-care costs and utilisation and to observe link worker delivery and patient engagement.

Data sources

Quality Outcomes Framework and Secondary Services Use data.

Design

Multimethods comprising (1) quasi-experimental evaluation of effects of social prescribing on health and health-care use, (2) cost-effectiveness analysis, (3) ethnographic methods to explore intervention delivery and receipt, and (4) a supplementary interview study examining intervention impact during the first UK COVID-19 lockdown (April–July 2020).

Study population and setting

Community-dwelling adults aged 40–74 years with type 2 diabetes and link workers in a socioeconomically deprived locality of North East England, UK.

Intervention

Link worker social prescribing to improve health and well-being-related outcomes among people with long-term conditions.

Participants

(1) Health outcomes study, approximately n = 8400 patients; EuroQol-5 Dimensions, five-level version (EQ-5D-5L), study, n = 694 (baseline) and n = 474 (follow-up); (2) ethnography, n = 20 link workers and n = 19 clients; and COVID-19 interviews, n = 14 staff and n = 44 clients.

Main outcome measures

The main outcome measures were glycated haemoglobin level (HbA1c; primary outcome), body mass index, blood pressure, cholesterol level, smoking status, health-care costs and utilisation, and EQ-5D-5L score.

Results

Intention-to-treat analysis of approximately 8400 patients in 13 intervention and 11 control general practices demonstrated a statistically significant, although not clinically significant, difference in HbA1c level (–1.11 mmol/mol) and a non-statistically significant 1.5-percentage-point reduction in the probability of having high blood pressure, but no statistically significant effects on other outcomes. Health-care cost estimates ranged from £18.22 (individuals with one extra comorbidity) to –£50.35 (individuals with no extra comorbidity). A statistically non-significant shift from unplanned (non-elective and accident and emergency admissions) to planned care (elective and outpatient care) was observed. Subgroup analysis showed more benefit for individuals living in more deprived areas, for the ethnically white and those with fewer comorbidities. The mean cost of the intervention itself was £1345 per participant; the incremental mean health gain was 0.004 quality-adjusted life-years (95% confidence interval –0.022 to 0.029 quality-adjusted life-years); and the incremental cost-effectiveness ratio was £327,250 per quality-adjusted life-year gained. Ethnographic data showed that successfully embedded, holistic social prescribing providing supported linking to navigate social determinants of health was challenging to deliver, but could offer opportunities for improving health and well-being. However, the intervention was heterogeneous and was shaped in unanticipated ways by the delivery context. Pressures to generate referrals and meet targets detracted from face-to-face contact and capacity to address setbacks among those with complex health and social problems.

Limitations

The limitations of the study include (1) a reduced sample size because of non-participation of seven general practices; (2) incompleteness and unreliability of some of the Quality and Outcomes Framework data; (3) unavailability of accurate data on intervention intensity and patient comorbidity; (4) reliance on an exploratory analysis with significant sensitivity analysis; and (5) limited perspectives from voluntary, community and social enterprise.

Conclusions

This social prescribing model resulted in a small improvement in glycaemic control. Outcome effects varied across different groups and the experience of social prescribing differed depending on client circumstances.

Future work

To examine how the NHS Primary Care Network social prescribing is being operationalised; its impact on health outcomes, service use and costs; and its tailoring to different contexts.

Trial registration

This trial is registered as ISRCTN13880272.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme, Community Groups and Health Promotion (grant no. 16/122/33) and will be published in full in Public Health Research; Vol. 11, No. 2. See the NIHR Journals Library website for further project information.

Oral nutritional interventions in frail older people who are malnourished or at risk of malnutrition: a systematic review

BACKGROUND

Malnutrition worsens the health of frail older adults. Current treatments for malnutrition may include prescribed oral nutritional supplements, which are multinutrient products containing macronutrients and micronutrients.

OBJECTIVE

To assess the effectiveness and cost-effectiveness of oral nutritional supplements (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Library, Scopus, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and grey literature were searched from inception to 13 September 2021.

REVIEW METHODS

A systematic review and meta-analysis was conducted to evaluate the effectiveness and cost-effectiveness of oral nutritional supplements in frail older people (aged ≥ 65 years) who are malnourished or at risk of malnutrition (defined as undernutrition as per National Institute for Health and Care Excellence guidelines). Meta-analysis and network meta-analysis were undertaken, where feasible, along with a narrative synthesis. A cost-effectiveness review was reported narratively. A de novo model was developed using effectiveness evidence identified in the systematic review to estimate the cost-effectiveness of oral nutritional supplements.

RESULTS

Eleven studies (n = 822 participants) were included in the effectiveness review, six of which were fully or partly funded by industry. Meta-analyses suggested positive effects of oral nutritional supplements compared with standard care for energy intake (kcal) (standardised mean difference 1.02, 95% confidence interval 0.15 to 1.88; very low quality evidence) and poor mobility (mean difference 0.03, p < 0.00001, 95% confidence interval 0.02 to 0.04; very low quality evidence) but no evidence of an effect for body weight (mean difference 1.31, 95% confidence interval -0.05 to 2.66; very low quality evidence) and body mass index (mean difference 0.54, 95% confidence interval -0.03 to 1.11; very low quality evidence). Pooled results for other outcomes were statistically non-significant. There was mixed narrative evidence regarding the effect of oral nutritional supplements on quality of life. Network meta-analysis could be conducted only for body weight and grip strength; there was evidence of an effect for oral nutritional supplements compared with standard care for body weight only. Study quality was mixed; the randomisation method was typically poorly reported. One economic evaluation, in a care home setting, was included. This was a well-conducted study showing that oral nutritional supplements could be cost-effective. Cost-effectiveness analysis suggested that oral nutritional supplements may only be cost-effective for people with lower body mass index (< 21 kg/m2) using cheaper oral nutritional supplements products that require minimal staff time to administer.

LIMITATIONS

The review scope was narrow in focus as few primary studies used frailty measures (or our proxy criteria). This resulted in only 11 included studies. The small evidence base and varied quality of evidence meant that it was not possible to determine accurate estimates of the effectiveness or cost-effectiveness of oral nutritional supplements. Furthermore, only English-language publications were considered.

CONCLUSIONS

Overall, the review found little evidence of oral nutritional supplements having significant effects on reducing malnutrition or its adverse outcomes in frail older adults.

FUTURE WORK

Future research should focus on independent, high-quality, adequately powered studies to investigate oral nutritional supplements alongside other nutritional interventions, with longer-term follow-up and detailed analysis of determinants, intervention components and cost-effectiveness.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42020170906.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 51. See the NIHR Journals Library website for further project information.

Living HTA: Automating Health Economic Evaluation with R

Background: Requiring access to sensitive data can be a significant obstacle for the development of health models in the Health Economics & Outcomes Research (HEOR) setting. We demonstrate how health economic evaluation can be conducted with minimal transfer of data between parties, while automating reporting as new information becomes available. Methods: We developed an automated analysis and reporting pipeline for health economic modelling and made the source code openly available on a GitHub repository. The pipeline consists of three parts: An economic model is constructed by the consultant using pseudo data. On the data-owner side, an application programming interface (API) is hosted on a server. This API hosts all sensitive data, so that data does not have to be provided to the consultant. An automated workflow is created, which calls the API, retrieves results, and generates a report. Results: The application of modern data science tools and practices allows analyses of data without the need for direct access – negating the need to send sensitive data. In addition, the entire workflow can be largely automated: the analysis can be scheduled to run at defined time points (e.g. monthly), or when triggered by an event (e.g. an update to the underlying data or model code); results can be generated automatically and then be exported into a report. Documents no longer need to be revised manually. Conclusions: This example demonstrates that it is possible, within a HEOR setting, to separate the health economic model from the data, and automate the main steps of the analysis pipeline.

Effectiveness and cost-effectiveness of oral nutritional supplements in frail older people who are malnourished or at risk of malnutrition: a systematic review and meta-analysis

BACKGROUND

Current management of malnutrition can include prescribed oral nutritional supplements (ONS); however, there is uncertainty whether these supplements are effective in people who are older (≥65 years) and frail. We assessed the effectiveness, cost-effectiveness, and adherence and acceptability of ONS in frail older people who are malnourished or at risk of malnutrition.

METHODS

In this systematic review and meta-analysis, five bibliographic databases (MEDLINE, EMBASE, Cochrane Library, Scopus, and CINAHL) and grey literature sources were searched from inception to Sept 13, 2021, to identify studies assessing the effectiveness and cost-effectiveness of ONS (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition. Multiple reviewers independently did study screening, data extraction, and risk of bias assessment. Quality was assessed using version 1.0 of the Cochrane risk of bias tool for randomised controlled trials (RCTs), and the BMJ Drummond checklist was used to assess the quality of the included cost-effectiveness study. A meta-analysis was done for the effectiveness review; for the other reviews, a narrative synthesis approach was used. This systematic review and meta-analysis was registered on PROSPERO, CRD42020170906.

FINDINGS

Of 8492 records retrieved and screened, we included 11 RCTs involving 822 participants, six of which were fully or partly funded by industry. For the majority of the outcomes for which meta-analyses were possible (11/12), Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessments suggested that the evidence was of very low certainty. Results suggested that ONS might have a slightly positive effect on energy (kcal) intake (standardised mean difference 1·02 [95% CI 0·15 to 1·88]; I²=87%; four studies), protein intake (standardised mean difference 1·67 [-0·03 to 3·37; I²=97%; four studies), and mobility (mean difference 0·03 [0·02 to 0·04]; I²=0%; four studies), compared with standard care. Narrative syntheses suggested that the effect of ONS on quality of life, compared with standard care, was mixed. In the identified studies, there was very little information related to active components, determinants, or acceptability of interventions. One economic evaluation, done in a care home setting, showed that ONS could be cost-effective.

INTERPRETATION

We found little evidence of ONS reducing malnutrition or its associated adverse outcomes in older people who are frail. High-quality, non-industry-funded, adequately powered studies reporting on short-term and long-term health outcomes, determinants, and participant characteristics are needed.

FUNDING

UK National Institute of Health and Care Research (NIHR) Health Technology Assessment (NIHR128729).

Living HTA: Automating Health Technology Assessment with R

Background: Requiring access to sensitive data can be a significant obstacle for the development of health models in the Health Economics & Outcomes Research (HEOR) setting. We demonstrate how health economic evaluation can be conducted with minimal transfer of data between parties, while automating reporting as new information becomes available. Methods: We developed an automated analysis and reporting pipeline for health economic modelling and made the source code openly available on a GitHub repository. The pipeline consists of three parts: An economic model is constructed by the consultant using pseudo data. On the data-owner side, an application programming interface (API) is hosted on a server. This API hosts all sensitive data, so that data does not have to be provided to the consultant. An automated workflow is created, which calls the API, retrieves results, and generates a report. Results: The application of modern data science tools and practices allows analyses of data without the need for direct access – negating the need to send sensitive data. In addition, the entire workflow can be largely automated: the analysis can be scheduled to run at defined time points (e.g. monthly), or when triggered by an event (e.g. an update to the underlying data or model code); results can be generated automatically and then be exported into a report. Documents no longer need to be revised manually. Conclusions: This example demonstrates that it is possible, within a HEOR setting, to separate the health economic model from the data, and automate the main steps of the analysis pipeline.

What is next in African neuroscience?

Working in Africa provides neuroscientists with opportunities that are not available in other continents. Populations in this region exhibit the greatest genetic diversity; they live in ecosystems with diverse flora and fauna; and they face unique stresses to brain health, including child brain health and development, due to high levels of traumatic brain injury and diseases endemic to the region. However, the neuroscience community in Africa has yet to reach its full potential. In this article we report the outcomes from a series of meetings at which the African neuroscience community came together to identify barriers and opportunities, and to discuss ways forward. This exercise resulted in the identification of six domains of distinction in African neuroscience: the diverse DNA of African populations; diverse flora, fauna and ecosystems for comparative research; child brain health and development; the impact of climate change on mental and neurological health; access to clinical populations with important conditions less prevalent in the global North; and resourcefulness in the reuse and adaption of existing technologies and resources to answer new questions. The article also outlines plans to advance the field of neuroscience in Africa in order to unlock the potential of African neuroscientists to address regional and global mental health and neurological problems.

OS10.5.A BrainWear: Longitudinal, objective assessment of physical activity in 42 HGG patients

BACKGROUND

In patients with High Grade Glioma (HGG), QoL and physical function decline with progressive disease (PD). Objective assessment of physical functioning is challenging as patients spend most of their time away from the hospital. Wearable technology allows measurement of objective, continuous activity data in a non-obtrusive manner. BrainWear is a phase II feasibility study, collecting longitudinal physical activity (PA) data from patients with primary and secondary brain tumours.

MATERIAL AND METHODS

All agreed to wear an Axivity AX3 triaxial accelerometer and completed the EORTC QLQ C30 and BN20, the Montreal Cognitive Assessment (MoCA) and Multidimensional fatigue inventory (MFI) questionnaires. Accelerometers were changed at 14-day intervals, and PRO questionnaires completed at pre-specified study intervals. Age-sex matched controls were identified from the UK Biobank 7-day accelerometer study. Raw accelerometer data was processed using UK Biobank accelerometer software and inclusion of high-quality wear time selected as ≥72 hours of data in a 7-day data collection and data in each 1-hour period of a 24-hour cycle over multiple days. We analysed variation in activity by patient demographics and treatment days. The wilcoxin-signed rank test was used to compare participant activity between radiotherapy treatment days and non-treatment days, mixed effects models were used to evaluate longitudinal changes in activity and we used k-means clustering to characterise clusters of PA behaviours.

RESULTS

We have collected 3458 days of accelerometer data from 42 HGG patients with a median age of 59, 80% of which has been classified as high quality. Patients &gt;60 years spend more time doing moderate activity compared to those &lt;60 years (52 vs 33 minutes/day, p=0.012), and there are significant differences in mean vector magnitude (17.12 vs 16.85 mg, p=0.013) and walking (91 vs 72 minutes/day) between radiotherapy and non-radiotherapy days. In patients having a 6-week RT course, time spent in daily moderate activity falls 4-fold between week 1 and the second week after RT completion (70 minutes to 16 minutes/day). Comparing HGG patients to healthy controls shows a significant difference in time spent across all activities (p&lt;0.05). K-means clustering analysis shows three distinct clusters, with 87% of HGG patients falling into the very inactive or moderately active groups.

CONCLUSION

Digital remote health monitoring is feasible and acceptable with 80% of data classified as high-quality wear-time suggesting good patient adherence. Triaxial accelerometer data collection captures objective evidence of a significant reduction in moderate daily activity at the time of expected peak RT side-effects and patients walk almost 30% less on non-RT treatment days. HGG patients show significantly lower levels of activity compared to matched healthy controls.

Synthesis, Characterization, and Magnetoresistive Properties of the Epitaxial Pd0.96Fe0.04/VN/Pd0.92Fe0.08 Superconducting Spin-Valve Heterostructure

A thin-film superconductor(S)/ferromagnet(F) F1/S/F2-type Pd0.96Fe0.04(20 nm)/VN(30 nm)/Pd0.92Fe0.08(12 nm) heteroepitaxial structure was synthesized on (001)-oriented single-crystal MgO substrate utilizing a combination of the reactive magnetron sputtering and the molecular-beam epitaxy techniques in ultrahigh vacuum conditions. The reference VN film, Pd0.96Fe0.04/VN, and VN/Pd0.92Fe0.08 bilayers were grown in one run with the target sample. In-situ low-energy electron diffraction and ex-situ X-ray diffraction investigations approved that all the Pd1-xFex and VN layers in the series grew epitaxial in a cube-on-cube mode. Electric resistance measurements demonstrated sharp transitions to the superconducting state with the critical temperature reducing gradually from 7.7 to 5.4 K in the sequence of the VN film, Pd0.96Fe0.04/VN, VN/Pd0.92Fe0.08, and Pd0.96Fe0.04/VN/Pd0.92Fe0.08 heterostructures due to the superconductor/ferromagnet proximity effect. Transition width increased in the same sequence from 21 to 40 mK. Magnetoresistance studies of the trilayer Pd0.96Fe0.04/VN/Pd0.92Fe0.08 sample revealed a superconducting spin-valve effect upon switching between the parallel and antiparallel magnetic configurations, and anomalies associated with the magnetic moment reversals of the ferromagnetic Pd0.92Fe0.08 and Pd0.96Fe0.04 alloy layers. The moderate critical temperature suppression and manifestations of superconducting spin-valve properties make this kind of material promising for superconducting spintronics applications.

Interstitial cells of Cajal and intestinal function in Trinidadian children

OBJECTIVE

This study was carried out to compare the density of the interstitial cells of Cajal (ICCs) in the bowel wall of children with Hirschsprung's disease (HD), anorectal malformations (ARM) and normal controls in Trinidad and Tobago.

SUBJECTS AND METHOD

Segments of bowel wall excised from eight children with HD, three controls and two children with ARM were immunostained with c-Kit primary antibody. Cells with features of ICCs were counted.

RESULTS

All three controls and the two children with ARM had dense distribution of ICCs. Most children (6/8; 75%) with HD had markedly reduced counts in aganglionic bowel. Two (25%) also had a decrease in ganglionic bowel. Possible influences were patient age and gender and the level of bowel sectioned.

CONCLUSION

Analysis of this sample suggests that immunostaining for c-Kit positive cells might be a useful screening test in the assessment of bowel motility disorders. The possible effects of age, gender and the level of bowel sampled await determination.

Linear and quadratic dispersion characterization of millimeter-length fibers and waveguides using common-path interferometry

We measured linear and quadratic dispersion on millimeter-length fibers, waveguides, and nanowires based on common-path spectral interferometry. We obtained the linear dispersion parameter, beta', with a relative precision of 1.45 x 10(-4), and extracted the quadratic dispersion parameter, beta'', from the Taylor expansion of beta' x beta'' values show a discrepancy of < 1% when compared with simulation as well as with measurement results obtained by a conventional Michelson interferometer. Using this method, we experimentally confirmed the sign inversion of the group velocity dispersion of AlGaAs nanowires for what is believed to be the first time.

Long-Term Variations in Optimal Programming of Cardiac Resynchronization Therapy Devices

The optimal follow-up and long-term programming of cardiac resynchronization therapy (CRT) devices are uncertain. The aim of this study was to quantify the temporal variations in programming parameters to optimize the follow-up of these devices. Before, during, and at specified intervals over 9 months after implant, 40 recipients of CRT devices were studied. At each visit, the patients were tested with a fixed sequence of stimulation parameters during echocardiographic and electrocardiographic (ECG) recordings. The optimal AV delay and inter-ventricular delays (V-V) were determined according to echocardiographic criteria. The echocardiographic data were, in turn, compared with the ECG recordings. Among the 40 patients, the optimal stimulation parameters remained unchanged throughout the follow-up in only three patients. In 18 patients, adjustments were required at each follow-up sessions. There was a trend toward reduction in the left ventricular (LV) predominance of the optimal V-V delay and an increase in the AV delay during follow-up. The mean optimal V-V delay at implant was 22 ms (-12 to +32 ms) with the LV activated first, versus 12 ms (-16 to +32 ms) at 9 months. The mean AV delay at implant was 115 ms versus 137 ms at 9 months. Individual changes could not be accurately predicted. The optimal stimulation parameters for CRT vary over time. Detailed, regular reevaluations, and reprogramming of optimal parameters may be appropriate.

Bifocal Right Ventricular Cardiac Resynchronization Therapies in Patients with Unsuccessful Percutaneous Lateral Left Ventricular Venous Access

Biventricular cardiac resynchronization therapy (CRT) with a lateral left ventricular (LV) lead cannot always be achieved. We report a single center experience of CRT utilizing a protocol that specifically required the implantation of a bifocal right ventricular (RV) lead system when lateral LV pacing could not be achieved. Consecutive candidates for CRT were included in the study. If strict criteria for lateral LV pacing were not met, they underwent implantation of a bifocal RV lead system with two 7F, active fixation leads, one placed septally at the apex, and the other in the high septal outflow tract. All patients were followed for 12 months and the two groups were compared. A biventricular (BiV) stimulation system was implanted in 44 patients, and a bifocal RV system in six. The demographic characteristics of the two groups were similar. Both groups experienced a similar improvement in functional capacity, increase in 6 minutes walking distance, and decreased need for hospitalizations. The mean increase in LV ejection fraction was 11% in the bifocal RV group versus 10% in the BiV group. Though the tissue Doppler indices of LV synchrony improved earlier in the BiV group, (19% vs 10%) the improvement was similar in both groups at 6 months (23% vs 20%). The clinical improvements conferred by CRT can be matched by a bifocal RV system in selected patients. This alternate approach should be considered when implantation of a LV lateral lead was unsuccessful.

A childhood malignant rhabdoid tumour of the kidney

A case report is presented of a malignant rhabdoid tumour occurring in the kidney of a 23-month-old boy. Important differences between this and the conventional Wilms' tumour include the histological demonstration of sheets or cords of large cells resembling myoblasts, a tendency to frequent clinical relapse, and a high mortality rate despite multimodal therapy. In this child, an encouraging initial response to pre-operative chemotherapy, followed by surgical excision and postoperative triple chemotherapy, was not sustained. Recurrence of pulmonary metastases did not respond to further chemotherapy and whole lung irradiation.

Cardiac fibroma presenting as sudden death in a six-month-old infant

Cardiac fibroma is a rare benign tumour which occurs predominantly in infancy and childhood. We present the case of a six-month-old female infant who died suddenly at home and was found at autopsy to have a large cardiac fibroma in the ventricular septum. The tumour was apparently asymptomatic although there was evidence of mild cardiac failure. Death was thought to be due to a fatal arrhythmia.

Nephrotic syndrome in Trinidadian children

57 children with idiopathic nephrotic syndrome who were seen at two hospitals in Trinidad between 1989 and 1995 (median follow-up period, 38 months) were classified according to their response to glucocorticoids. 27 (47%) were two to six years old at presentation; 37 (65%) were of East Indian descent, 7 (12%) were of African descent, and 12 (21%) were of mixed race. 55 (96%) responded to glucocorticoids. Renal biopsies in 15 patients revealed membranoproliferative glomerulonephritis and membranous nephropathy in the two patients who had not responded to glucocorticoids. Ten patients showed mesangial hypercellularity, associated with immunoglobulin deposits in 7 cases. Age, presentation with nephrotic features, mesangial hypercellularity and immunoglobulin deposits did not predict for unresponsiveness to glucocorticoids. These findings may be explained by the predominance of East Indians in the study group.

Oxygen-induced lung injury in the pre-term guinea pig: the role of leukotriene B4

Leukotriene B4 (LTB4) has been reported to promote the formation of lung oedema when infused into the pulmonary circulation of adult animals. The present study evaluated the hypothesis that LTB4 was responsible, in part, for the oedema that develops during oxidative injury of the immature lung. Significant increases were found in LTB4 concentration in bronchoalveolar lavage fluid obtained from pre-term guinea pig pups maintained in 95% oxygen for 48 h (P < 0.05) and 72 h (P < 0.05) compared to pups maintained in 21% oxygen. Cellular analysis of lavage fluid revealed a concurrent influx of neutrophils into the hyperoxic-injured lung at these times. The protein concentration of lavage fluid was also increased by 48-h hyperoxia exposure indicating elevated pulmonary microvascular permeability. In a second series of experiments, pups exposed to 95% oxygen (and 21% oxygen controls) were treated with a specific LTB4 antagonist (U-75302), at either 0.5, 1.5 or 3.0 mg 100 g body wt to ascertain if LTB4 played a role in either neutrophil recruitment or oedema formation in the immature lung. The number of neutrophils recovered in bronchoalveolar lavage fluid was significantly reduced, compared to vehicle-treated pups, in pups treated with U-75302, at both 1.5 and 3.0 mg/100 g body wt but not 0.5 mg/100 g body wt. Histopathological analysis of pups treated with 1.5 mg U-75302/100 g body wt revealed fewer neutrophils in the pulmonary interstitium (198 vs. 218 mm-2, P < 0.05). The extent of lung microvascular permeability, elevated by hyperoxic exposure, was modulated by increasing concentrations of U-75302. Specifically, treatment with 0.5, 1.5 and 3.0 mg U-75302/100 g body wt reduced microvascular permeability by 17, 67 and 98%, respectively. In conclusion, LTB4 plays an important role in oedema formation in acute oxidative injury of the immature lung and this is mediated, in part, through neutrophils.

Transformation-derived Neisseria gonorrhoeae plasmids with altered structure and function

Plasmid deoxyribonucleic acid from Neisseria gonorrhoeae containing a 7.1-kilobase (kb) (4.7-megadalton) penicillinase (Pcr) plasmid transformed homogenic gonococci to penicillinase production at a low frequency. About 25% of the penicillinase-producing gonococcal transformants contained Pcr plasmids which were either larger or smaller than the 7.1 kb donor plasmid; these Pcr plasmids varied in size from 3.45 to 42 kb. Some of these altered plasmids differed from the donor plasmid in stability or in frequency of mobilization by a 36-kb (24-megadalton) conjugative plasmid. A restriction endonuclease cleavage map of the 7.1-kilobase Pcr plasmid and several of the smaller deleted plasmids was constructed. The most common size of altered Pcr plasmid was 5.1 kb (3.4 megadaltons). A Pcr plasmid isolated from a gonococcus in London, England, was identical with these 5.1-kb transformant plasmids in both size and restriction endonuclease cleavage profiles, suggesting that the 5.1-kb Pcr plasmid could have arisen from a 7.1-kb Pcr plasmid by a transformation-associated deletion in nature.

Conjugative plasmids in Neisseria gonorrhoeae

A conjugation system initially discovered in beta-lactamase-producing gonococci mobilized small non-selftransmissible R plasmids encoding beta-lactamase (penicillinase) production into other gonococci, Neisseria, and Escherichia coli. This conjugation system was mediated by a separate selftransmissible plasmid of 23.9 X 10(6) daltons, pFA2. Conjugative plasmids capable of mobilizing R plasmids were also found in nearly 8% of the non-penicillinase-producing gonococci. These were similar to pFA2 in size, buoyant density, and restriction endonuclease digest patterns but were less efficient than pFA2 in mobilization of the penicillinase plasmid pFA3. The presence of conjugative plasmids in gonococci isolated before the appearance of penicillinase-producing strains indicates that a conjugation system for plasmid transfer predated the appearance of R plasmids in gonococci.