An integrated assessment framework for climate change and infectious diseases

Many potential human health effects have been hypothesized to result either directly or indirectly from global climate change. Changes in the prevalence and spread of infectious diseases are some of the most widely cited potential effects of climate change, and could have significant consequences for human health as well as economic and societal impacts. These changes in disease incidence would be mediated through biologic, ecologic, sociologic, and epidemiologic processes that interact with each other and which may themselves be influenced by climate change. Although hypothesized infectious disease effects have been widely discussed, there have not yet been thorough quantitative studies addressing the many processes at work. In part this is because of the complexity of the many indirect and feedback interactions or mechanisms that bear on all aspects of the climate issue. It also results from the difficulty of including the multitude of always-changing determinants of these diseases. This paper proposes a framework for an integrated assessment of the impacts of climate change on infectious diseases. The framework allows identification of potentially important indirect interactions or mechanisms, identification of important research gaps, and a means of integrating targeted research from a variety of disciplines into an enhanced understanding of the whole system.

The vagaries of self-reports of physical activity: a problem revisited and addressed in a study of exercise promotion in the over 65s in general practice

BACKGROUND

The assessment of levels of physical activity relies upon suitable measurement tools.

OBJECTIVE

We aimed to investigate whether a practice nurse, using a motivational interview technique, could encourage older patients to increase their physical activity.

METHODS

Health and well-being were monitored at baseline and 8 weeks following intervention. Physical activity levels were ascertained using both a self-report measure and ambulatory heart-rate monitoring.

RESULTS

Whilst patients reported higher levels of physical activity at follow-up, this finding was not confirmed by the heart-rate data.

CONCLUSION

The study concludes that patients tend to overestimate the amount of physical activity undertaken and that ambulatory heart-rate monitoring may be more useful for verifying actual behaviour.

Mailed reminders for area-wide influenza immunization: a randomized controlled trial

OBJECTIVE

To determine if mailed reminders would increase area-wide influenza immunization for persons aged 65 and older.

DESIGN

A randomized, controlled trial.

SETTING

Ten counties in Indiana.

PARTICIPANTS

Using a Medicare database, 10,000 subjects were selected randomly from 10 counties in Indiana and randomized for the study. Using pre-established criteria, 4503 persons in the control group and 4508 in the intervention group were eligible for study.

INTERVENTION

Intervention subjects received mailed reminders during the immunization season of 1995.

MEASUREMENTS

Data from mailed surveys, Medicare claims, and phone calls were used to determine immunization rates.

RESULTS

Of those surveyed who received immunization, only 63.4% filed a Medicare claim. Immunization rates were high in both groups but higher in the intervention group, 69.0% versus 64.2%. Age, presence of lung disease, assignment to the intervention group, presence of heart disease, and an age-sex interaction term were significantly and independently related to immunization.

CONCLUSIONS

The Healthy People Year 2000 goal (60% immunization for persons 65 and older) was exceeded in this population. Medicare claims data do not reflect immunization rates accurately. Mailed reminders, an inexpensive intervention, increased immunization rates area-wide and have potential for cost savings.

An evaluation of the Team Objective Structured Clinical Examination (TOSCE)

OBJECTIVES

To evaluate the validity, reliability and feasibility of the TOSCE, a new means of formative assessment for medical students, from the perspectives of examiners, simulated patients and students.

DESIGN

Teams of five students rotate through five clinical stations, performing one of four tasks in turn, whilst the fifth member of the team 'rests'.

SETTING

St George's Hospital Medical School, London.

SUBJECTS

Third-year medical students, their examiners and simulated patients.

RESULTS

All participants felt the TOSCE session had high validity although some students were unfamiliar with some subjects. Stations were double-marked and agreement rates and Cohen's Kappa ranged from 67 to 94% and 0.04-0.88, respectively. Analysis of the causes of disagreement led to improved marking schedules and enhanced reliability.

CONCLUSIONS

The feasibility of the exercise as a formative assessment was demonstrated by the confidence of the staff participating both as examiners and simulated patients and from the majority of students who welcomed the learning experience.

General practitioners' continuing education: a review of policies, strategies and effectiveness, and their implications for the future

BACKGROUND

The accreditation and provision of continuing education for general practitioners (GPs) is set to change with new proposals from the General Medical Council, the Government, and the Chief Medical Officer.

AIM

To review the theories, policies, strategies, and effectiveness in GP continuing education in the past 10 years.

METHOD

A systematic review of the literature by computerized and manual searches of relevant journals and books.

RESULTS

Educational theory suggests that continuing education (CE) should be work-based and use the learner's experiences. Audit can play an important role in determining performance and needs assessment, but at present is largely a separate activity. Educational and professional support, such as through mentors or co-tutors, has been successfully piloted but awaits larger scale evaluation. Most accredited educational events are still the postgraduate centre lecture, and GP Tutors have a variable role in CE management and provision. Controlled trials of CE strategies suggest effectiveness is enhanced by personal feedback and work prompts. Qualitative studies have demonstrated that education plays only a small part in influencing doctors' behavior.

CONCLUSION

Maintaining good clinical practice is on many stakeholders' agendas. A variety of methods may be effective in CE, and larger scale trials or evaluations are needed.

Achilles tendon rupture and sciatica: a possible correlation

The association between Achilles tendon rupture and sciatica was investigated by questionnaire in 138 patients who underwent repair of an Achilles tendon rupture, and in a group of individuals nominated by the patients, matched for age, sex, and occupation. A total of 102 patients (74%) and 128 peer nominated controls (71%) replied to the questionnaire. Of the 102 respondent patients, 18 had an officebased job, 47 were involved in skilled nonmanual work, and 16 were retired. Back pain had been experienced by 63 of the patients who replied to the questionnaire, and by 91 (75%) of the individuals in the control group (difference not significant). In about 30% of both groups, the pain confined them to bed for at least two days, and resulted in absence from work. Thirteen of the patients and 16 of the controls had undergone thoracic, lumbar, or sacral radiography. One individual in each group had received surgery for back pain. However, 35 of 102 patients had experienced sciatic pain before Achilles tendon rupture. Pain of a similar nature had been experienced by only 15 individuals in the control group (12%) (p < 0.001). Using this study design, we found a highly significant association between Achilles tendon rupture and sciatica. We propose that this association could be due to impaired afferent signals from the lower leg, or to similar collagen or vascular anomalies of the vertebral disc and the Achilles tendon.

Can practice nurses increase physical activity in the over 65s? Methodological considerations from a pilot study

There is ample evidence of the benefits of exercise for older people. Less is known about the most effective strategies for promoting the participation of older people in exercise regimes. An approach whereby practice nurses used motivational interviewing, based on Prochaska and Di Clemente's model of behaviour change, was piloted in two general practices. The strategy appeared feasible and will be tested further in a large controlled trial.

Regional localization of specific [125I]leptin binding sites in rat forebrain

Specific [125I]leptin receptor binding sites have been identified in choroid plexus (CP), but have eluded regional localization within the brain parenchyma. To optimize specific [125I]leptin binding in brain loci, we ran experiments varying the pH of incubation buffers. We found that specific [125I]leptin binding in CP was strikingly pH dependent with the most acidic buffer, pH 5.5, resulting in a greater than 100% increase over the amount of specific binding measured at pH 7.5. While low pH permitted detection of specific binding in parenchymal loci, clear pH dependency was only observed in the CP. In the caudate putamen (CauP), a locus with low specific binding, values for specific binding did not differ significantly across the range of pH conditions tested. Using incubation buffers at pH 6.0 in subsequent binding experiments, we localized specific [125I]leptin binding in several brain loci including thalamus and hypothalamus. In CP and thalamus, where the range of OD permitted analysis of binding parameters, [125I]leptin binding was saturable with increasing concentrations of unlabelled leptin. In all loci, specific [125I]leptin binding was insensitive to competition by high concentrations of other unlabelled compounds. Our results varying pH conditions of the incubation buffer suggest leptin receptors may be divided into subclassifications based on pH sensitivity of the specific binding. Furthermore, our results suggest that although densities are low, high affinity leptin receptors are present in neural loci implicated in food intake and energy balance, and are more widespread in the forebrain than previously determined.

The London Academic Training Scheme (LATS): an evaluation

BACKGROUND

A recognition of the inability of vocational training schemes (VTS) to teach all the skills needed for modern general practice, and the increasing unwillingness of vocationally trained doctors to commit to GP principal posts, has led to the promotion and piloting of post-VTS educational schemes. The London Academic Training Scheme (LATS) is a year's attachment to a University Department of General Practice in London, comprising seven academic and three clinical sessions.

OBJECTIVE

We aimed to carry out an evaluation of the first 2 years of the LATS from the perspectives of the registrar, their departmental supervisor and the practice.

METHODS

Data were collected by questionnaires, interviews and focus groups, at the beginning, during and at the end of the scheme.

RESULTS

Results are available up to the midway point of the second (1996) intake. The registrars achieved confidence and success in research, with six publications in peer-referenced journals from the first cohort so far. Eight of this cohort were working in inner London 6 months later, seven in academic posts. The overwhelming career intention of the second cohort midway is to work in academic general practice in London. The registrars enjoyed their teaching opportunities and increased their confidence but would have liked more training and more time for teaching. All the supervisors identified positive effects on their departments, but some found the time commitment and the process of supervision challenging. Two out of the dozen practices involved with the first cohort had reservations about the attachment. The rest cited benefits in clinical care, involvement in research and time for their own development.

CONCLUSION

The scheme fulfilled its immediate aims and is addressing the recruitment and retention of GPs in the inner city. Continuing follow-up is planned.

Prolonged Captopril Therapy in Murine Viral Myocarditis

BACKGROUND: Acute myocarditis can progress to chronic heart muscle disease and cardiomyopathy. In the coxsackievirus B(3) (CB(3)) mouse model of myocarditis, early administration of captopril, an angiotensin-converting enzyme (ACE) inhibitor, ameliorated histopathological changes in inflammation, necrosis, and calcification and reduced heart weight. Late administration of captopril reduced heart weight but did not affect the histological findings. In this study, we investigated the effects of prolonged captopril treatment in the chronic phase of this model. METHODS AND RESULTS: Three-week-old male CD(1) mice were infected with CB(3) and then randomized to receive placebo or captopril starting on day 7 of infection. Captopril, 2 g/L, was given as the drinking water daily for up to 6 months. Autopsies were performed at 6 and 10 months. Heart-to-body weight ratios were obtained, and deaths were tallied. Myocardial fibrosis was graded according to a score system. In addition, picrosirius red stain (PSR) also was used for assessment of collagen deposition. Mean heart weights were similar in both groups. Mean body weight was significantly lower in captopril-treated mice (40.7 g) than in the untreated group (43.6 g) at 6 months (P =.0155), and mortality was higher (8.7 vs 0.87%; P =.009). At 6 months, the mean myocardial fibrosis score in treated mice (0.12) was significantly less than in untreated animals (0.35; P =.035). With PSR, the mean myocardial fibrosis score in the captopril group (1.20) was also significantly less than in the untreated group (1.58; P =.045). At 10 months, fibrosis scores were similar in both groups. CONCLUSIONS: Chronic captopril treatment in CB(3) myocarditis reduces myocardial fibrosis.

Resident human hepatic lymphocytes are phenotypically different from circulating lymphocytes

BACKGROUND/AIMS

Murine and human studies have documented the existence of subpopulations of lymphocytes in particular tissues that differ phenotypically and functionally from those in peripheral blood and may mature locally. Since little is known about lymphocyte subpopulations in the normal human liver, we have analysed the surface phenotypes of lymphocytes isolated from liver specimens taken from 15 donors at the time of liver transplantation, and compared these with those of peripheral blood lymphocytes.

METHODS

Hepatic lymphocytes were prepared by mechanical dissociation and enzymatic digestion of liver tissue. The cells were stained with a panel of monoclonal antibodies (CD3, CD4, CD8, CD19, CD56, gammadeltaTCR, alphabetaTCR, CD8alpha-chain, CD8alphabeta dimer), and analysed by flow cytometry. In situ characterisation of hepatic lymphocytes was by haematoxylin and eosin staining of fixed liver sections and by immunohistochemical staining for common leukocyte antigen and CD3.

RESULTS

Significant numbers of hepatic T lymphocytes were localised to the portal tracts and parenchyma of normal liver specimens. Flow cytometry revealed that the CD4/CD8 ratio (1:3.5) was consistently reversed compared with that in peripheral blood (2:1). Other lymphocyte populations identified include double positive CD3+CD4+CD8+ cells which accounted for a mean of 5.5% (range 3-11.6%) of hepatic CD3+ cells compared with 1.3% in blood (range 0.7-3.6%; p < 0.007), and double negative CD3+ CD4-8- cells (14.5%; range 2.7-29% compared with 5.0%; range 2.1-10.8%, p < 0.02). Over 15% (range 6.8-34%) of all hepatic CD3+ cells expressed a gammadeltaTCR compared to 2.7% (range 0.9-4.7%) of CD3+ peripheral blood lymphocytes (p < 0.004) and almost 50% of these coexpressed CD8. The CD8 alpha-chain was expressed without the beta-chain (CD8alpha+beta-) by 15.4% (range 4-29.1%) of hepatic T cells, but this phenotype was undetectable among peripheral blood lymphocytes (p < 0.009). Cells expressing both the T cell marker CD3 and the natural killer cell marker CD56 constituted 31.6% (range 14-54%) of all hepatic CD3+ lymphocytes but were rarely present amongst peripheral blood lymphocytes (0-6%; p < 0.0001).

CONCLUSIONS

These data are the first to describe and quantify unconventional T lymphocyte subpopulations in the normal adult human liver which may have specialised functions in regional immune responses and which may differentiate locally. These findings have important implications for our understanding of hepatic immunoregulation and the pathogenic mechanisms involved in viral and immune-mediated liver disease and allograft rejection.

Defective mammopoiesis, but normal hematopoiesis, in mice with a targeted disruption of the prolactin gene

Prolactin (PRL) has been implicated in numerous physiological and developmental processes. The mouse PRL gene was disrupted by homologous recombination. The mutation caused infertility in female mice, but did not prevent female mice from manifesting spontaneous maternal behaviors. PRL-deficient males were fertile and produced offspring with normal Mendelian gender and genotype ratios when they were mated with heterozygous females. Mammary glands of mutant female mice developed a normal ductal tree, but the ducts failed to develop lobular decorations, which is a characteristic of the normal virgin adult mammary gland. The potential effect of PRL gene disruption on antigen-independent primary hematopoiesis was assessed. The results of this analysis indicated that myelopoiesis and primary lymphopoiesis were unaltered in the mutant mice. Consistent with these observations in PRL mutant mice, PRL failed to correct the bone marrow B cell deficiency of Snell dwarf mice. These results argue that PRL does not play any indispensable role in primary lymphocyte development and homeostasis, or in myeloid differentiation. The PRL-/- mouse model provides a new research tool with which to resolve a variety of questions regarding the involvement of both endocrine and paracrine sources of PRL in reproduction, lactogenesis, tumorigenesis and immunoregulation.

Oncostatin M stimulates monocyte chemoattractant protein-1- and interleukin-1-induced matrix metalloproteinase-1 production by human synovial fibroblasts in vitro

OBJECTIVE

To measure levels of oncostatin M (OSM) in the synovial fluid of rheumatoid arthritis (RA) patients and to examine the activities of human OSM in the regulation of human synovial fibroblast (HSF) production of chemokines and matrix metalloproteinases (MMP-1 and MMP-3) in vitro.

METHODS

We examined the levels of OSM in the synovial fluids of patients with arthritis by an enzyme-linked immunosorbent assay (ELISA). ELISA of cell culture supernatants and Northern blots were used to assess responses of HSF to interleukin-1alpha (IL-1alpha), OSM, and other members of the IL-6/leukemia inhibitory factor (IL-6/LIF) family of cytokines.

RESULTS

We detected variable levels of OSM antigen in 9 of 10 RA patient synovial fluids, but levels were not detectable in 9 of 10 osteoarthritis (OA) patient fluids. Upon examining the responses of HSF in culture, OSM stimulated monocyte chemoattractant protein 1 (MCP-1), whereas RANTES secretion (regulated upon activation, normal T expressed and presumably secreted) was not altered by OSM alone. In IL-1alpha-induced cells, OSM costimulation further enhanced MCP-1 release, but inhibited the release of RANTES and IL-8. Other members of the IL-6/LIF family of cytokines did not show these effects. OSM induced a small elevation of MMP-1 production over 2 and 3 days of stimulation (2-fold), and acted significantly to enhance IL-1alpha-induced production of MMP-1 (to 8-fold and 9-fold at 48 and 72 hours, respectively). No effect of OSM was seen on MMP-3 secretion, either alone or in IL-1alpha-costimulated cells.

CONCLUSION

These results suggest that OSM has potentially important functions in the modulation of chemokine and metalloproteinase production by synovial cells of the joint.

Health state utilities in knee replacement surgery: the development and evaluation of McKnee

OBJECTIVE

1. To develop McKnee, a classification system and direct utility measure for health states associated with knee replacement (KR) surgery. 2. To apply McKnee in a before-after study of KR surgery to: (i) gain experience with McKnee in an elderly population; (ii) confirm the practicality and usefulness of the McKnee system; (iii) assess self-health utility one week before and 3 mo after surgery; (iv) evaluate the stability of 3 clinical marker health states describing mild, moderate, and severe knee disability; (v) compare self-health utility scores with Short Form 36 (SF-36).

METHODS

1. Instrument development: The McKnee modified Health Utilities Index was developed and used to describe self-health and clinical marker health states: the clinical validity of the clinical marker states was evaluated by 5 clinicians involved in the care off KR patients. 2. Instrument evaluation: McKnee and the SF-36 were administered to 48 patients with osteoarthritis one week before and 3 mo after KR surgery.

RESULTS

Before-after study: McKnee was feasible and acceptable in the older patient group studied (mean age in years, SD: 69.9, 8.6). No change in self-health utility (mean, SD) was observed at 3 mo postsurgery: before -0.78, 0.17; after -0.78, 0.21. On the SF-36, only the change scores for pain and health transition were statistically significant. Utilities (mean, SD) for the clinical marker health states were: mild -0.80, 0.20; moderate -0.55, 0.28; and severe -0.48, 0.31. The clinical marker mean utility scores were stable between the baseline and 3 mo assessment, but the intraclass correlation coefficients for individual scores were low.

CONCLUSION

McKnee provides a preference based measure of health related quality of life that can be used to obtain and interpret clinically the knee disability utility scorers needed for cost-utility studies and medical decision-making models about KR surgery. The McKnee system provides a practical and useful method for classifying knee disability health states and obtaining direct measurements of utility scores for selected health states.

[Advantages in long-term treatment with Cognex in Alzheimer disease]

Early diagnosis and treatment of AD is critical to maximize benefits for the patient and the caregiver. It is important to intervene early in the illness, before the quality of life of the patient and the caregiver has deteriorated to the point where treatment only prolongs an already difficult situation. If treatment begins early enough in the disease course, loss of functional independence may be delayed, just as nursing home placement was delayed in this study. In this way, quality of life is improved for both the patient and the caregiver.

Phase II trial of raltitrexed ('Tomudex') in advanced small-cell lung cancer

Raltitrexed, a thymidylate synthase inhibitor, was given to 21 patients with advanced small-cell lung cancer, at a dose of 3 mg m(-2) as a 15-min intravenous infusion at 21-day intervals. All of the patients had extensive disease and 17 had received prior therapy. Patients with disease refractory to primary chemotherapy were excluded. Forty-one treatment cycles were given (median two, range one to four). The drug was well tolerated. No objective tumour response was documented. The patients had chemoresistant disease, as shown by a response in only one of ten patients who went on to receive alternative cytotoxic regimens. We conclude that raltitrexed given in this schedule is inactive as second line therapy for small-cell lung cancer.