Towards co-design of rehabilitation technologies: a collaborative approach to prioritize usability issues

Introduction

Early stakeholder engagement is critical to the successful development and translation of rehabilitation technologies, a pivotal step of which is usability testing with intended end-users. To this end, several methods employ end-user feedback to identify usability and implementation issues. However, the process of prioritizing identified issues seldom leverages the knowledge and expertise of the range of stakeholders who will ultimately affect the demand and supply of a device. This paper describes a novel method to prioritize end-user feedback using transdisciplinary stakeholder consultation and address it in subsequent product development. The proposed approach was demonstrated using a case study relating to the development of a novel technology for neural recovery after spinal cord injury.

Method

Feedback from five individuals with chronic spinal cord injury was collected during two-hour usability evaluation sessions with a fully functional high-fidelity system prototype. A think-aloud and semi-structured interview protocol was used with each participant to identify usability and acceptability issues relating to the system in a 3-phase approach. Phase 1 involved extracting usability issues from think-aloud and semi-structured interview data. Phase 2 involved rating the usability issues based on their significance, technical feasibility, and implementation priority by relevant internal and external stakeholders. Finally, Phase 3 involved aggregating the usability issues according to design and implementation elements to facilitate solution generation, and these solutions were then raised as action tasks for future design iterations.

Results

Sixty usability issues representing nine facets of usability were rated. Eighty percent of issues were rated to be of moderate to high significance, 83% were rated as being feasible to address, and 75% were rated as addressable using existing project resources. Fifty percent of the issues were rated to be a high priority for implementation. Evaluation of the grouped issues identified 21 tasks which were mapped to the product roadmap for integration into future design iterations.

Discussion

This paper presents a method for meaningful transdisciplinary stakeholder engagement in rehabilitation technology development that can extended to other projects. Alongside a worked example, we offer practical considerations for others seeking to co-develop rehabilitation technologies.

A 2-year longitudinal evaluation of the impact of the COVID-19 pandemic on individuals with pre-existing anxiety disorders

OBJECTIVES

To examine if the COVID-19 pandemic is associated with a differential effect over a 2-year time period in relation to its psychological and social impact on patients with established anxiety disorders.

METHODS

Semi-structured interviews were conducted with 21 individuals attending the Galway-Roscommon Mental Health Services in Ireland with an ICD-10 diagnosis of an anxiety disorder. Interviews occurred at three time-points over a 2-year period to determine the impact of the COVID-19 pandemic and associated restrictions on anxiety and depressive symptoms, social and occupational functioning, and quality of life.

RESULTS

No statistical difference in symptomatology was noted between the three time-points in relation to anxiety symptoms as measured utilising psychometric rating scales (Beck Anxiety Inventory (BAI), Hamilton Anxiety Rating Scale (HARS) or Likert Scale measures). The greatest impact of COVID-19 at all time-points related to social functioning and quality of life. Significant variability was noted for individual participants. Qualitative analysis noted a tentative optimism for the future in the setting of vaccination and societal re-opening. Fear of re-emerging anxiety symptoms with the removal of societal restrictions was noted.

CONCLUSIONS

No significant overall change in symptomatology or functioning over time was noted for individuals with pre-existing anxiety disorders, however variability was demonstrated, with some individuals describing ongoing anxiety, social isolation and concern for their future. A strong theme of hope for the future and less concern regarding the COVID-19 pandemic was evident; however tailored supports including the utilisation of tele-psychiatry is suggested, particularly for those experiencing increased anxiety with the removal of societal restrictions.

Kynanthropic and vampirism delusions: a case report and review of the literature

Zooanthropy (delusional beliefs of turning into an animal) is a rare but well recognised psychiatric phenomenon. This case describes the presence of kynanthropic delusions (delusional beliefs of turning into a dog). Multiple other psychotic symptoms were also evident including unusually the additional presence of delusions of vampirism. Delusional beliefs in this case were associated with behavioural changes including growling and barking, and less commonly an expressed craving for biting people's necks to suck human blood. Symptom intensity was associated with increased psychosocial stressors for this patient, with some benefit noted from very high doses of anti-psychotic medications. Brief admissions to the acute psychiatric inpatient unit and thus removal from environmental stressors has been associated with an amelioration in symptomatology.

Nasopharyngeal Pneumococcal Colonization Density is Associated with Severe Pneumonia in Young Children in the Lao PDR

Background

No studies have explored the association between pneumococcal nasopharyngeal density and severe pneumonia using the World Health Organization (WHO) 2013 definition. In Lao People’s Democratic Republic (Lao PDR), we determine the association between nasopharyngeal pneumococcal density and severe pneumonia in children.

Methods

A prospective observational study was undertaken at Mahosot Hospital, Vientiane, from 2014 to mid-2018. Children <5 years admitted with acute respiratory infections (ARIs) were included. Clinical and demographic data were collected alongside nasopharyngeal swabs for pneumococcal quantification by lytA real-time quantitative polymerase chain reaction. Severe pneumonia was defined using the 2013 WHO definition. For pneumococcal carriers, a logistic regression model examined the association between pneumococcal density and severe pneumonia, after adjusting for potential confounders including demographic and household factors, 13-valent pneumococcal conjugate vaccine status, respiratory syncytial virus co-detection, and preadmission antibiotics.

Results

Of 1268 participants with ARI, 32.3% (n = 410) had severe pneumonia and 36.9% (n = 468) had pneumococcal carriage. For pneumococcal carriers, pneumococcal density was positively associated with severe pneumonia (adjusted odds ratio, 1.4 [95% confidence interval, 1.1–1.8]; P = .020).

Conclusions

Among children with ARIs and pneumococcal carriage, pneumococcal carriage density was positively associated with severe pneumonia in Lao PDR. Further studies may determine if pneumococcal density is a useful marker for pneumococcal conjugate vaccine impact on childhood pneumonia.

Vascular Endothelial Growth Factor Levels in Serum and Plasma following Esophageal Cancer Resection - Relationship to Platelet Count

In patients with cancer circulating vascular endothelial growth factor (VEGF) may be tumor-derived and have prognostic significance. Activated platelets may also be a source of VEGF, releasing it in serum formation. Debate exists as to whether serum or plasma VEGF (S-VEGF, P-VEGF) is the most appropriate surrogate marker of tumor angiogenesis. As healing wounds produce VEGF that can spill over into the circulation, we aimed to investigate the potential confounding effects of cancer surgery on both perioperative S-VEGF and P-VEGF levels and to evaluate their relationship with platelet count. S-VEGF, P-VEGF and platelet counts were measured in 23 patients undergoing esophageal cancer resection. Samples were taken preoperatively and six weeks following surgery. Seven patients were also sampled on postoperative days 1, 5 and 10. VEGF was assayed using a commercial enzyme linked immunosorbent assay. S-VEGF and P-VEGF both rose after surgery (S-VEGF; day 5: 1017 [446–1224] pg/mL and day 10: 1231 [626–2046] pg/mL versus pre-op: 329 [189–599] pg/mL. P-VEGF; day 1: 55 [46–104] pg/mL and day 10: 58 [20–154] pg/mL versus pre-op: 23 [13–46] pg/mL), falling towards pre-operative levels by six weeks. Platelet count correlated with S-VEGF (rho=0.281; p<0.05, Spearman's rank) and P-VEGF (rho=0.330; p<0.01, Spearman's rank). Platelets may contribute to VEGF levels in plasma as well as in serum. The effects of surgery on S-VEGF or P-VEGF levels are mainly transient. Care must be exercised when interpreting circulating VEGF levels in the early postoperative period.

Childhood pneumonia and crowding, bed-sharing and nutrition: a case-control study from The Gambia

SETTING

Greater Banjul and Upper River Regions, The Gambia.

OBJECTIVE

To investigate tractable social, environmental and nutritional risk factors for childhood pneumonia.

DESIGN

A case-control study examining the association of crowding, household air pollution (HAP) and nutritional factors with pneumonia was undertaken in children aged 2-59 months: 458 children with severe pneumonia, defined according to the modified WHO criteria, were compared with 322 children with non-severe pneumonia, and these groups were compared to 801 neighbourhood controls. Controls were matched by age, sex, area and season.

RESULTS

Strong evidence was found of an association between bed-sharing with someone with a cough and severe pneumonia (adjusted OR [aOR] 5.1, 95%CI 3.2-8.2, P < 0.001) and non-severe pneumonia (aOR 7.3, 95%CI 4.1-13.1, P < 0.001), with 18% of severe cases estimated to be attributable to this risk factor. Malnutrition and pneumonia had clear evidence of association, which was strongest between severe malnutrition and severe pneumonia (aOR 8.7, 95%CI 4.2-17.8, P < 0.001). No association was found between pneumonia and individual carbon monoxide exposure as a measure of HAP.

CONCLUSION

Bed-sharing with someone with a cough is an important risk factor for severe pneumonia, and potentially tractable to intervention, while malnutrition remains an important tractable determinant.

Re-Staging Following Long-Course Chemoradiotherapy For Rectal Cancer: Does It Influence Management?

BACKGROUND

In patients with locally advanced or low rectal cancers, long-course chemoradiotherapy (LCCRT) is recommended prior to surgical management.¹ The need for restaging afterwards has been questioned as it may be difficult to interpret imaging due to local tissue effects of chemoradiotherapy. The purpose of this study was to determine if restaging affected the management of patients receiving long-course chemoradiotherapy for rectal cancer.

METHODS

A retrospective review of patients with rectal cancer discussed at the South Eastern Health and Social Care Trust Lower Gastrointestinal Multi-Disciplinary Team Meeting (LGIMDT) in 2013 who had received long-course chemoradiotherapy was performed. Patients were identified from the Trust Audit Department, LGIMDT notes and patient records. Imaging results and outcomes from meetings were obtained through the Northern Ireland Picture Archiving and Communications System^® (NIPACS) and Electronic Care Record^® (ECR). Data including patient demographics, initial radiological staging and LGIMDT discussion, restaging modality and result, outcome from post-treatment LGIMDT discussion and recorded changes in management plans were documented using a proforma.

RESULTS

Seventy-one patients with rectal cancer were identified as having LCCRT in 2013 (M:F 36:35; age range 31 - 85 years). Fifty-nine patients were restaged following long-course treatment with computed tomography (CT) and magnetic resonance imaging (MRI). Twelve patients did not undergo restaging. Data was not available for 6 patients, one patient underwent emergency surgery, two patients were not fit for treatment, one failed to attend for restaging and two patients died prior to completion of treatment. Of the 59 patients restaged, 19 patients (32%) had their management plan altered from that which had been proposed at the initial LGIMDT discussion. The most common change in plan was not to operate. Ten patients had a complete clinical and radiological response to treatment and have undergone intensive follow-up. Nine patients had disease progression, with 3 requiring palliative surgery and 6 referred for palliative care.

CONCLUSION

Of those patients who were restaged, 32% had their management plan altered from that recorded at the initial LGIMDT discussion. Seventeen per cent of patients in this group had a complete clinical and radiological response to treatment. Fifteen percent demonstrated disease progression. We recommend, therefore, that patients with rectal cancer be restaged with CT and MRI following long-course chemoradiotherapy as surgery may be avoided in up to 27% of cases.

Phase II meningococcal B vesicle vaccine trial in New Zealand infants

BACKGROUND

A tailor-made serogroup B outer membrane vesicle vaccine was evaluated in the context of a serogroup B meningococcal epidemic dominated by Neisseria meningitidis strain B:4:P1.7b,4.

OBJECTIVE

To determine the safety, reactogenicity and immunogenicity in infants aged 6-8 months of a meningococcal B vaccine developed against the New Zealand epidemic strain.

DESIGN, SETTING AND PARTICIPANTS

Observer-blind, randomised, controlled trial conducted in 296 healthy infants in Auckland, New Zealand.

INTERVENTION

Infants were randomised 4:1 to receive three doses of New Zealand candidate vaccine (epidemic strain NZ98/254, B:4:P1.7b,4) or meningococcal C conjugate vaccine at 6-weekly intervals.

MAIN OUTCOME MEASURES

Immune response was determined by human complement mediated serum bactericidal assay. Sero-response was a fourfold or greater rise in titre compared to baseline, with baseline titres <4 required to increase to >or=8. Blood samples were taken before vaccination, 6 weeks after dose two, and 4 weeks after dose three. Local and systemic reactions were recorded for 7 days following vaccination.

RESULTS

Sero-response to the candidate vaccine strain, NZ98/254, was demonstrated in 74% of vaccinees (95% CI: 68% to 80% intention-to-treat; 67% to 79% per protocol) after three doses of New Zealand candidate vaccine. No meningococcal C conjugate vaccine recipients were sero-responders to NZ98/254 after three doses. Both vaccines were well tolerated with no vaccine related serious adverse events.

CONCLUSIONS

Our data indicate that the New Zealand candidate vaccine administered in three doses to this group of 6-8-month-old infants was safe and immunogenic against the candidate vaccine strain NZ98/254 (Neisseria meningitidis B:4:P1.7b,4).

Safety and immunogenicity of New Zealand strain meningococcal serogroup B OMV vaccine in healthy adults: Beginning of epidemic control

As the first step towards control of a strain specific epidemic of meningococcal disease in New Zealand (NZ), this study, an observer-blind, randomised controlled trial in 75 healthy adults, evaluated safety and immunogenicity of two different dosages of a meningococcal group B vaccine administered in a three dose regime. The "tailor-made" outer membrane vesicle (OMV) vaccine (candidate vaccine) developed using a New Zealand meningococcal group B strain (B:4:P1.7b,4) was well tolerated with no vaccine related serious adverse events. Similar local and systemic reactions were observed in those receiving the New Zealand candidate vaccine and the control parent Norwegian vaccine (MenBvac). A four-fold rise in serum bactericidal antibodies (SBAb) against the vaccine strain 4-6 weeks after the third vaccination was achieved in 100% of New Zealand candidate vaccine 2,519 microg participants and in 87% of 50 microg participants. The safety and immunogenicity profile observed in this study of healthy adults enabled studies in children to be initiated using 25 microg dosage.

Bleeding gastric varices--a rare complication of ovarian cancer

Splenic venous hypertension (or 'left-sided portal hypertension') is a rare underlying cause of gastro-oesophageal varices. Ovarian carcinoma recurring beyond 10 years, following primary treatment with no interval disease, is also a rare occurrence. We report an unusual case of bleeding gastric varices secondary to splenic venous obstruction as a result of metastatic ovarian carcinoma. This occurred 21 years following surgery and adjuvant chemotherapy for primary ovarian carcinoma. To our knowledge, until now, there have been no reported cases of splenic venous hypertension due to ovarian carcinoma. This case report illustrates the successful emergency management of this condition by splenectomy, with complete resolution of varices confirmed endoscopically at 6 weeks. It is followed by a brief discussion regarding varices due to splenic venous hypertension.

Increased nm23 immunoreactivity is associated with selective inhibition of systemic tumour cell dissemination

AIMS

In vitro transfection experiments show that the nm23 gene suppresses metastasis, although the evidence from clinical studies is contradictory. The purpose of this study was to investigate whether nm23 selectively influences systemic, pleural, and lymphatic metastasis in non-small cell lung cancer (NSCLC).

METHODS

Forty two patients undergoing resection of NSCLC and lymph node sampling were enrolled prospectively. In each case, a bone marrow aspirate, pleural lavage, and lymph nodes were assessed using immunohistochemistry for epithelial antigens and morphology. The intensity of nm23-H1 immunoreactivity of the primary tumour was compared with the internal control of normal bronchial epithelium in 32 cases where available. The microvessel count (MVC) of each tumour was determined using immunohistochemistry for the endothelial cell marker CD34.

RESULTS

Tumour cell dissemination was detected in the bone marrow in 18 patients, in the pleura in seven, and in the lymph nodes in 21. Increased immunoreactivity for nm23 was found in the primary tumour in six patients, with none having tumour cells in the bone marrow, compared with 12 of 26 patients who showed nm23 immunoreactivity equal to or less than the control (Fisher's exact test: p = 0.043). This effect was confirmed to be independent of the MVC on multivariate analysis. There was no significant difference in the incidence of pleural or lymphatic tumour cell dissemination between the two groups.

CONCLUSION

nm23 appears to be a suppressor of systemic, but not lymphatic, metastasis in primary NSCLC.

Older workers' progression from private disability benefits to Social Security disability benefits

People with medical conditions that limit their ability to work tend to receive short-term disability benefits initially and may then move to long-term and eventually to permanent disability benefits. The progression of older workers (those aged 55 to 64) along that continuum of benefits is documented here with data from a large disability insurance company. The data show that older workers who receive short-term medical disability benefits are three times as likely as younger workers to progress to receipt of Social Security Disability Insurance (SSDI) benefits, although a slight reversal of that trend occurs as workers pass age 62. Musculoskeletal conditions are the most frequent basis of short-term disability claims among older workers, with circulatory conditions running a close second. Furthermore, although all medical conditions are more likely to lead to SSDI benefits among older workers, circulatory conditions do so most frequently. This article discusses industry standards for the management of disability claims at each level of severity. It also addresses common and emerging disability management practices that may reduce the likelihood of impaired workers developing long-term or permanent financial dependence on disability benefits programs.

Multi-drug resistant Pseudomonas aeruginosa outbreak in a burns unit--an infection control study

A newly introduced, multi-drug resistant (MDR) strain of Pseudomonas aeruginosa was isolated from four patients admitted to the Concord Hospital Burns Unit (BU) between December 1997 and March 1998. It was the cause of recurrent episodes of bacteraemia in two. This strain was resistant in vitro to gentamicin, piperacillin and ciprofloxacin. The isolates were confirmed as a clonal strain by pulse field gel electrophoresis (PFGE). Multiple environmental swabs were taken to search for an environmental reservoir, but no source was identified. Random cultures of staff members' hands failed to demonstrate ongoing carriage. In the absence of a demonstrable point source for the outbreak, direct cross-transmission patient to patient, via transient staff hand contamination, was the most likely route of infection. Following study commencement no new cases of infection with the MDR strain were detected. It would appear that the infection cycle has been interrupted, and the outbreak terminated following the discharge of the last infected patient from the BU. Contamination of a neutral detergent in the BU with Klebsiella oxytoca was detected incidentally during environmental surveillance. A potential hospital-wide outbreak was averted.

Evaluation of vaccines to prevent childhood pneumonia: lessons relevant to planning tuberculosis vaccine trials

Bacterial pneumonia in children is usually caused by one of the two leading pathogens, Streptococcus pneumoniae (pneumococcus) and Haemophilus influenzae, either type b (Hib) or nonencapsulated types. Hib conjugate vaccines suitable for use in infants have been available for about a decade, and experience with a trial of one of these vaccines in Africa showed that the vaccines can prevent Hib pneumonia, as well as other manifestations of Hib disease. It also showed that vaccine trials can provide useful estimates of the role of Hib in childhood pneumonia. Trials of pneumococcal conjugate vaccines that are currently under way have been designed to estimate disease burden and efficacy. A major risk of vaccine trials that use bacteriologic end points is that the vaccine may affect the diagnostic test itself, creating a misleading impression of efficacy. Trials of future tuberculosis vaccines are discussed in light of these experiences. It is important that the trials are designed to measure the effect on all clinical disease, as well as strict microbiological end points. The existence of bacille Calmette-Guérin (BCG) complicates future trials, and such trials should take into account possible nonspecific effects of BCG in addition to its effect on tuberculosis.

Effect of fever on the serum antibody response of Gambian children to Haemophilus influenzae type b conjugate vaccine

BACKGROUND

Acute malaria is a major pediatric problem in developing countries and it is known to be immunosuppressive.

METHODS

The serum antibody response to Haemophilus influenzae type b (Hib) conjugate vaccine was investigated in children ages 12 to 30 months with fever associated with malaria, fever associated with other causes or no fever. Groups of 57 children with malaria, 57 children with fever without malaria and 60 healthy children were bled and vaccinated with a single dose of H. influenzae type b capsular polysaccharide-tetanus protein conjugate vaccine. Of these 137 were bled again 1 to 2 months after vaccination.

RESULTS

The median antibody titers at baseline were low and similar in the three groups; 77, 65 and 57% of children in the malaria, febrile and healthy groups, respectively, had prevaccination titers of anti-polyribosylribitol phosphate antibodies below 0.15 microg/ml. The median antibody titers after vaccination were 6.3, 7.5 and 23 microg/ml in the malaria, febrile and healthy groups, respectively (P < 0.001, healthy group vs. the two febrile groups). All the healthy children had protective titers (>0.15 microg/ml) after vaccination, but 11% of the children with malaria and 4% of the other febrile children did not have protective titers.

CONCLUSIONS

Anti-polyribosylribitol phosphate titers after Hib vaccination were lower in children with malaria or other febrile illnesses at the time of vaccination than in controls. Fever associated with malaria or other acute illnesses is associated with a diminished response to Hib conjugate vaccine. These findings raise questions about the vaccination of febrile children and indicate the need for further studies in this area.

Respiratory illness after severe respiratory syncytial virus disease in infancy in The Gambia

OBJECTIVE

To determine the frequency of later respiratory tract morbidity after respiratory syncytial virus (RSV) disease in infancy.

DESIGN

Cohort study with passive, clinic-based surveillance.

SETTING

Outpatient department in The Gambia.

SUBJECTS

One hundred five children admitted to the hospital with severe RSV disease (case cohort), 105 control children matched for age not admitted to the hospital during the previous RSV season (control cohort 1), and 102 control children born after the RSV season (control cohort 2).

MAIN OUTCOME MEASURES

Frequencies of pneumonia, wheezing, and hospital admission with acute lower respiratory tract infection.

RESULTS

Pneumonia was more common in case children than in both control groups (adjusted incidence rate ratio [IRR, 95% CI]: 3.80 [2.73, 6. 10]), as was wheezing (IRR 7.33 [3.10,17.54]), pneumonia or wheezing (IRR 3.96 [2.60, 6.04]), and admission with pneumonia or wheezing (IRR 3.40 [1.87, 6.15]). The incidence rate per 100 child-years for pneumonia in the dry season for 12-month-old children was 27 for case patients, 8.1 for control cohort 1, and 6.51 for control cohort 2. By 3 years of age, the rates had fallen to low levels in all groups.

CONCLUSIONS

Pneumonia and wheezing are significantly more common in children after RSV-associated lower respiratory tract disease than in control subjects, but the incidence declines rapidly with increasing age.

Haemophilus influenzae type b meningitis in The Gambia after introduction of a conjugate vaccine

After the introduction of a Haemophilus Influenzae type b (Hib) conjugate vaccine into The Gambia, the annual incidence of Hib meningitis has fallen from more than 200 per 100,000 before vaccination to 21 per 100,000 during the past 12 months.

A randomised trial of a Haemophilus influenzae type b conjugate vaccine in a developing country for the prevention of pneumonia--ethical considerations

In 1993 a placebo-controlled field trial of a Haemophilus influenzae type b (Hib) conjugate vaccine was started in The Gambia. At that time Hib conjugate vaccines had been shown to be efficacious in Europe and North America for the prevention of Hib meningitis. However doubts remained about their value in developing countries, where the epidemiology of Hib disease is quite different and the most important manifestation of Hib disease is pneumonia. The ethical issues facing the investigators before and during the trial are outlined in this paper, along with the views of the different groups involved in the trial. The trial demonstrated the efficacy of the vaccine in this setting and revealed the proportion of childhood pneumonia that is likely due to Hib, which was much higher than had previously been estimated. Since the completion of the trial Hib vaccines are now recommended for use in developing countries by the World Health Organization, largely based on the results of this trial. After a delay of 17 months following the completion of the trial, national Hib vaccination was started in The Gambia in 1997 using vaccine provided by a donation from industry.

Strategies for the control of pneumococcal diseases

Streptococcus pneumoniae (pneumococcus) is a Gram-positive, encapsulated bacteria that is a major cause of human disease in people of all ages. It is the most important cause of bacterial pneumonia in infancy, childhood and adult life, and the most important cause of meningitis in all age groups except children of 3 months to 2 years in whom Haemophilus influenzae type b (Hib) predominates (in the absence of Hib vaccination). Antibodies to the pneumococcal polysaccharide capsule are protective, and at present 90 capsular serotypes are recognized. The global burden of pneumococcal disease is poorly understood. It is believed to be responsible for 1-2 million deaths among children under 5 years of age every year and probably a similar number among adults. Thus, the global burden of pneumonia in adults is probably significantly underestimated at present. Strategies for the control of pneumococcal disease include control of risk factors, treatment of established cases and vaccination. In children, improved nutrition, better housing and reduced indoor air pollution are difficult to address, but should eventually reduce pneumonia rates. In adults, the risk factors are even more difficult to address, although control of alcohol and tobacco consumption and reduced transmission of HIV should all affect pneumococcal disease rates. Penicillin-resistant pneumococci are now widespread throughout the world. Where penicillin resistance occurs, penicillin should not be used to treat pneumococcal meningitis; however, penicillin, at higher doses if necessary, remains the drug of choice for the treatment of pneumococcal pneumonia, even where penicillin resistance is prevalent. There are three approaches to pneumococcal vaccination: polysaccharide vaccines (covering 23 serotypes), polysaccharide-protein conjugate vaccines (covering 9-11 serotypes) and common protein vaccines (which are not serotype-specific). Only polysaccharide vaccines are available now, but conjugate vaccines will be available soon. Polysaccharide vaccines probably have a role in protecting the elderly from pneumococcal disease, especially those at high risk. The potential role of conjugate vaccines in infants is unclear.

Clinical predictors of hypoxaemia in Gambian children with acute lower respiratory tract infection: prospective cohort study

OBJECTIVES

To determine clinical correlates and outcome of hypoxaemia in children admitted to hospital with an acute lower respiratory tract infection.

DESIGN

Prospective cohort study.

SETTING

Paediatric wards of the Royal Victoria Hospital and the hospital of the Medical Research Council's hospital in Banjul, the Gambia.

SUBJECTS

1072 of 42 848 children, aged 2 to 33 months, who were enrolled in a randomised trial of a Haemophilus influenzae type b vaccine in the western region of the Gambia, and who were admitted with an acute lower respiratory tract infection to two of three hospitals.

MAIN OUTCOME MEASURES

Prevalence of hypoxaemia, defined as an arterial oxygen saturation <90% recorded by pulse oximetry, and the relation between hypoxaemia and aetiological agents.

RESULTS

1072 children aged 2-33 months were enrolled. Sixty three (5.9%) had an arterial oxygen saturation <90%. A logistic regression model showed that cyanosis, a rapid respiratory rate, grunting, head nodding, an absence of a history of fever, and no spontaneous movement during examination were the best independent predictors of hypoxaemia. The presence of an inability to cry, head nodding, or a respiratory rate >/= 90 breaths/min formed the best predictors of hypoxaemia (sensitivity 70%, specificity 79%). Hypoxaemic children were five times more likely to die than non-hypoxaemic children. The presence of malaria parasitaemia had no effect on the prevalence of hypoxaemia or on its association with respiratory rate.

CONCLUSION

In children with an acute lower respiratory tract infection, simple physical signs that require minimal expertise to recognise can be used to determine oxygen therapy and to aid in screening for referral. The association between hypoxaemia and death highlights the need for early recognition of the condition and the potential benefit of treatment.

Antigenuria in Gambian infants following immunization with a Haemophilus influenzae type b polyribosylribitol phosphate-tetanus toxoid protein conjugate (PRP-T) vaccine

During a Haemophilus influenzae type b (Hib)-conjugate vaccine trial, the prevalence and duration of antigenuria after vaccination was studied in 102 Gambian infants aged 51 to 175 days. Urine samples were collected at 0, 1, 3, 7, 14, 21 and 28 days postvaccination and tested for Hib antigen by latex agglutination using Biomérieux and Directigen reagent kits. Biomérieux positive reactions were found in 6 of 247 (2.4%) samples from vaccinated children and in 8 of 199 (4.0%) from nonvaccinated children (chi 2 = 0.47; 1 df; p = 0.5). In contrast, Directigen positive reactions were obtained with 86/242 samples (35.5%) from vaccinated children and from 28/190 (14.7%) from non-vaccinated children (chi 2 = 22.7; 1 df; p < 0.0001). The highest rate of antigenuria was detected in samples collected on Day 7 after vaccination when 24 of 30 (80%) were positive. Antigenuria following vaccination was frequent and may complicate the use of this test as a means of diagnosing invasive Hib disease in vaccinated children.

Clinical predictors of malaria in Gambian children with fever or a history of fever

Diagnosis of malaria in children is difficult without laboratory support because the symptoms and signs of malaria overlap with those of other febrile illnesses such as pneumonia. Nevertheless, in many parts of Africa diagnosis of malaria must be made without laboratory investigation. Therefore, a scoring system has been developed to assist peripheral health care workers in making this diagnosis. Four hundred and seven Gambian children aged 6 months to 9 years who presented to a rural clinic with fever or a recent history of fever were investigated. A diagnosis of malaria was made in 159 children who had a fever of 38 degrees C or more and malaria parasitaemia of 5000 parasites/microL or more. Symptoms and signs in children with malaria were compared with those in children with other febrile illnesses to identify features which predicted malaria. Symptoms and signs were incorporated into various logistic regression models to test which were best independent predictors of malaria and these regression models were used to construct simple scoring systems which predicted malaria. A nine terms model predicted clinical malaria with a sensitivity of 89% and a specificity of 61%, values comparable to those obtained by an experienced paediatrician without laboratory support. The ability of peripheral health care workers to diagnose malaria using this approach is now being investigated in a prospective study.

A polymerase chain reaction for the diagnosis of Haemophilus influenzae type b disease in children and its evaluation during a vaccine trial

BACKGROUND

Determination of the etiology of pneumonia in young children is difficult because blood culture, the usual method of diagnosis, is positive in only a small proportion of cases. For this reason vaccine trials that include bacterial pneumonia as an endpoint must be large.

OBJECTIVES

To determine whether a diagnostic test based on a polymerase chain reaction could be used as an alternative to conventional blood culture for diagnosis of invasive Haemophilus influenzae type b (Hib) infections in young children investigated during the course of a large vaccine trial.

METHODS

DNA was extracted from blood culture supernatants and probed for the presence of Hib DNA with a PCR assay with primers derived from the cap gene locus of Hib. Results of the PCR assay were compared with those obtained by conventional culture techniques.

RESULTS

Blood cultures were obtained from 1544 children with suspected pneumonia, meningitis or septicemia and from 31 healthy control children who were contacts of cases. Blood culture supernatants were tested for Hib DNA in the PCR test. The sensitivity and specificity of a positive PCR test in blood culture supernatant as against culture of Hib from any normally sterile site were 100 and 99%, respectively. Eleven children had positive Hib PCR tests on blood culture supernatants but were negative by culture. In one of these cases Hib was isolated from a lung aspirate and in two other patients H. influenzae strains other than Hib were obtained from the cerebrospinal fluid. Eight of these 11 children were in the control group. When the results of the PCR assay were used to determine vaccine efficacy, a value of 86% was obtained compared with a figure of 95% obtained when conventional culture techniques were used.

CONCLUSIONS

An Hib PCR assay on blood culture supernatants proved to be sensitive and specific for the diagnosis of Hib disease in children. The distribution of PCR-positive, culture-negative cases between Hib-vaccinated and control groups paralleled that of culture-positive cases, suggesting that most of these children had been infected with Hib. A trial of a highly efficacious vaccine provides a novel way for evaluating new diagnostic tests for which there is no standard diagnostic test of 100% reliability.

Epidemiology of invasive pneumococcal disease in the Western Region, The Gambia

BACKGROUND

Streptococcus pneumoniae is a major cause of morbidity and mortality in young children in the developing world. The recent development of pneumococcal polysaccharide/protein conjugate vaccines may make possible prevention of this infection. However, little is known about the epidemiology of invasive pneumococcal disease in children in the developing world.

OBJECTIVES

To determine the incidence and epidemiologic features of invasive pneumococcal disease in children resident in a semiurban area of The Gambia.

METHOD

The study was part of a large trial of an Haemophilus influenzae type b vaccine that recruited 42 848 children at the age of 2 months during the period March, 1993, to October, 1995. Follow-up of study children continued until December 31, 1995; therefore the first children to enter the trial were followed for 2.5 years and the last for just a few months. During the period of surveillance, 2256 children were investigated for possible invasive pneumococcal disease when they presented to a hospital or health center.

RESULTS

We detected 110 cases of pneumococcal disease. Pneumonia was the most common form of invasive pneumococcal disease observed (75.5% of patients). The incidence of pneumococcal disease was 224 [95% confidence interval (CI) 171, 277] per 100,000 child years among children ages 2 to 11 months, 139 (95% CI 93, 184) per 100,000 among children ages 12 to 23 months and 82 (95% CI 21, 143) per 100,000 among children ages 24 to 35 months. Pneumococci of serogroups 14, 6, 5, 23, 19, 46 and 2 were isolated most frequently. Susceptibility to pneumococcal disease was not increased significantly among Haemophilus influenzae type b-vaccinated children.

CONCLUSIONS

The pneumococcus is a major cause of bacterial infection in The Gambia. A proposed nine-valent pneumococcal conjugate vaccine for developing countries containing conjugates of serogroups 1, 4, 5, 6, 9, 14, 18, 19 and 23 would cover 74% of cases of invasive pneumococcal disease in children resident in the Western Region of The Gambia.

Randomised trial of Haemophilus influenzae type-b tetanus protein conjugate vaccine [corrected] for prevention of pneumonia and meningitis in Gambian infants

BACKGROUND

In developing countries, pneumonia and meningitis due to Haemophilus influenzae type b (Hib) are common in children under age 12 months and the mortality from meningitis is high. Protein-polysaccharide conjugate vaccines have brought Hib disease under control in industrialised countries. We did a double-blind randomised trial in The Gambia to assess the efficacy of a Hib conjugate vaccine for the prevention of meningitis, pneumonia, and other invasive diseases due to Hib.

METHODS

Between March, 1993, and October, 1995, 42,848 infants were randomly allocated the conjugate vaccine Hib polysaccharide tetanus protein (PRP-T) mixed with diphtheria-tetanus-pertussis vaccine (DTP), or DTP alone at age 2 months, 3 months, and 4 months. Children who presented with signs of invasive Hib were investigated by blood culture and, where appropriate, by lumbar puncture, chest radiograph, or percutaneous lung aspirate. Children were followed up for between 5 and 36 months.

FINDINGS

The median ages at which children received the study vaccine were 11 weeks, 18 weeks, and 24 weeks. 83% of children enrolled received all three doses of vaccine. 17 cases of culture-positive Hib pneumonia, 28 of Hib meningitis, and five of other forms of invasive Hib disease were detected amongst the study children. The efficacy of the vaccine for the prevention of all invasive disease after three doses was 95% (PRP-T vaccinees 1, controls 19 [95% CI 67-100]), for the prevention of Hib pneumonia after two or three doses, 100% (vaccinees 0, controls 10 [55-100]), and for the prevention of radiologically defined pneumonia at any time after enrollment, 21.1% (PRP-T vaccinees 198, controls 251 [4.6-34.9]).

INTERPRETATION

PRP-T conjugate Hib vaccine prevented most cases of meningitis and pneumonia due to Hib in Gambian infants. The reduction in the overall incidence of radiologically defined pneumonia in PRP-T vaccinees suggests that about 20% of episodes of pneumonia in young Gambian children are due to Hib. The introduction of Hib vaccines into developing countries should substantially reduce childhood mortality due to pneumonia and meningitis.

Maternal immunization with Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine in The Gambia

OBJECTIVE

To evaluate maternal responses to Haemophilus influenzae type b (Hib) polysaccharide-tetanus protein conjugate (polyribosylribitol phosphate-tetanus or PRP-T) given to pregnant Gambian women, the transplacental transfer of antibody, and the effect of maternal immunization on infant responses to the vaccine.

DESIGN

An open, randomized immunogenicity study.

SETTING

A busy urban health center in The Gambia.

STUDY PARTICIPANTS

A total of 451 pregnant women enrolled during the third trimester of pregnancy.

INTERVENTION

Study participants were randomized to three groups. In one group, mothers were given PRP-T during the third trimester and their infants were given PRP-T at 2, 3, and 4 months of age. In the second group, mothers received PRP-T and infants were given inactivated poliovirus vaccine. In the third group, mothers received meningococcal A and C vaccine, and their infants received PRP-T.

MAIN OUTCOME MEASURES

Anti-PRP antibody measurements of maternal cord, and infant blood.

RESULTS

Vaccinated women had a marked increase in total anti-PRP antibody (geometric mean titer 9.0 micrograms/mL), which was greatest in women in their first or second pregnancy. Previous tetanus vaccination during the same pregnancy and high concentrations of antitetanus antibody were associated with lower anti-PRP responses. In infants of PRP-T recipients, cord blood anti-PRP IgG concentrations were 61% of simultaneous maternal concentrations. In vaccinated infants of vaccinated mothers, geometric mean anti-PRP antibody concentrations at birth, 2 months of age, and 5 months of age were 1.92, 0.35 and 2.84 micrograms/mL, respectively, while in vaccinated infants of unvaccinated mothers, the corresponding concentrations were 0.29, 0.12, and 3.91 micrograms/mL. At 2 months of age, 60% of infants of vaccinated mothers and 26% of infants of unvaccinated mothers had anti-PRP antibody concentrations considered to be protective (>0.15 micrograms/mL).

CONCLUSIONS

In areas where much invasive Hib disease occurs in infants younger than 6 months, maternal immunization may help to reduce the risk of Hib disease in infants too young for immunization.

Species differences in 5-HT autoreceptors

Release of 5-HT in the CNS is under the control of autoreceptors. These autoreceptors fall into two categories: cell body autoreceptors and terminal autoreceptors. The former inhibit 5-HT release through inhibition of cell firing; the latter through direct inhibition of release at the terminal. Cell body (or somatodendritic) autoreceptors belong to the 5-HT1A receptor subtype in all species studied so far. In the rat and mouse, the terminal autoreceptor is known to be a 5-HT1B receptor, whereas in human, pig, rabbit, and guinea pig, the terminal autoreceptor is thought to belong to the 5-HT1D receptor subtype. Until recently, the absence of a potent and selective 5-HT1D receptor antagonist has hindered this classification. We now present data with the novel 5-HT1D receptor antagonist, GR 127935, which demonstrates that in guinea pig cerebral cortex the terminal autoreceptor is a 5-HT1D receptor. In vitro [3H]5-HT release studies demonstrate that 5-HT inhibition of [3H]5-HT release is attenuated by GR 127935. In vivo, using the technique of microdialysis, GR 127935 and the non-selective antagonist methiothepin, when administered down the dialysis probe, potentiate extracellular levels of 5-HT. Both the in vitro and in vivo effects of these compounds are consistent with terminal autoreceptor blockade. However, when GR 127935 and methiothepin were administered systemically, both compounds inhibit extracellular levels of 5-HT. The most plausible explanations for this effect, such as partial agonism or activation of somatodendritic 5-HT1A receptors, are discussed.

Infection associated with central venous catheters: a prospective survey

OBJECTIVE

To assess the incidence of local and systemic infection caused by central venous catheters in a general hospital population.

SETTING

Concord Repatriation General Hospital, Sydney, April to August 1991 inclusive.

DESIGN

A prospective survey of all patients with in situ central venous catheters. Systemic catheter-related infection was detected by blood and routine catheter tip culture, and local infection by clinical observation of the catheter exit site.

OUTCOME MEASURES

Local and systemic infection and complications.

RESULTS

479 central venous catheters were surveyed in 311 patients. Local infection developed in association with 54 catheters (11%) and systemic infection with 32 (6.7%). Local infection was predictive of systemic infection, but its absence did not exclude systemic infection. Haemodialysis catheters were responsible for a higher systemic infection rate than other catheter types, the most common organism responsible being methicillin-resistant Staphylococcus aureus. Twenty per cent of all bacteraemias (33/160) detected in the hospital occurred in patients with a central venous catheter and 24 of these (73%) were definitely or probably due to the catheter. Staphylococci were the predominant isolates and 40% of the methicillin-resistant S. aureus bacteraemias detected were due to catheter-related infection. Infection complications were few: three patients developed local abscesses; one endocarditis; and two died.

CONCLUSIONS

Central venous catheter-related infection is common in general hospital populations. Staphylococcal bacteraemia and local infection in a patient with a central venous catheter are strongly suggestive of catheter-related systemic infection. Empirical antibiotic treatment should include at least antistaphylococcal cover.

Administration of recombinant enkephalinase (neutral endopeptidase) prevents capsaicin-induced miosis in the rabbit eye in vivo

Substance P induced a dose-dependent contraction of iris sphincter muscles when applied in the presence of atropine to the isolated rabbit iris in vitro as evidenced by a decreased pupil diameter. Pretreatment of the iris with 20 micrograms of recombinant enkephalinase (neutral endopeptidase; EC 3.4.24.11) totally abolished the contractile response to substance P. Injection of 10 micrograms of capsaicin into the anterior chamber of atropine-treated rabbit eyes in vivo induced an immediate and intense miosis. Injection of 100 micrograms of recombinant enkephalinase, 1 or 5 min before capsaicin injection, significantly inhibited this miosis. This effect of enkephalinase was totally abolished by preincubating the enzyme with thiorphan, a high-affinity enkephalinase inhibitor. These results show that enkephalinase, which is known to hydrolyze substance P in vitro with high efficiency, also hydrolyzes endogenously released substance P in vivo. Furthermore, our results suggest that enkephalinase application may represent a novel therapeutic approach to treat substance P-mediated pathologies.

Cholera in Sudan: An account of an epidemic in a refugee camp in eastern Sudan, May-June 1985

In 1985 cholera has been a serious problem in the horn of Africa, particularly affecting the many famine victims and refugees in that region. In this paper the history of cholera in Africa is briefly summarized, as is the background to the current refugee situation in eastern Sudan. A cholera epidemic involving 1,175 cases in two adjacent refugee camps in eastern Sudan is described. In this epidemic there were thirteen inpatient deaths and thirty-eight known home deaths from cholera. The management of the epidemic is described in detail. Overall an average of 8 1. of intravenous fluid was used per case, a higher figure than was anticipated, probably because of the unexpected degree of vomiting and the shortage of trained nursing staff. The relationship between cholera and malnutrition is explored and hypochlorhydria is suggested as the main reason for the increased susceptibility to cholera among malnourished populations. It was observed that severely malnourished adults and children appeared to nave less severe diarrhoea with their cholera, presumably because of reduced mucosal surface area and poor enterocyte function. Finally possible means of aborting cholera epidemics are discussed.

Maternal and childhood nutrition among Aborigines of the Kimberley region

A cross-sectional anthropometric survey of 128 Aboriginal children under five years of age and of 388 Aboriginal girls and women of child-bearing age was undertaken in seven communities in the Kimberley Region of Western Australia. More than 20% of the children were undernourished, three individuals severely so. All but one of those who were undernourished were over 12 months of age. Less than 60% of the female subjects of child-bearing age had a satisfactory nutritional status; one-sixth were undernourished and one-quarter, mostly older women, were overweight. The findings indicate that poor nutrition is widespread among Aboriginal female subjects of child-bearing age. Maternal malnutrition may contribute significantly to unsatisfactory nutrition and health in Aboriginal infants and young children.