Validating record-linkage based methodology for addressing health survey non-participation

Background

As a consequence of declining levels of participation in health surveys, the results purported to be population-representative may be biased. Traditional adjustments for non-participation, such as weighting, can fail to correct for such biases. We aim to validate our developed methodology, which simulates non-participants, and compare results from the inferred sample to the ’gold standard’ sample of participants and true non-participants, and participants alone.

Methods

Participants and non-participants of the Finnish Health 2000 survey, and a contemporaneous population sample are available, with alcohol-related hospitalisations and deaths (“harms”, individually record-linked for all Health 2000 invitees). Synthetic observations on non-participants were simulated through comparison of participants and population sample. Alcohol consumption of true and inferred non-participants were multiply imputed based on harms and education as well as age and sex, assuming data are Missing At Random (MAR). Results are compared via the relative differences (RD) between the inferred sample and 1) gold standard sample, and 2) participants alone.

Results

Average weekly estimates for men are 129g in the inferred sample, and 130g in the gold standard (RD -1.2%, 95%CI -2.0, -0.4%), and 35g for women in both samples (RD -0.8%; -1.9, 0.3%). Estimates for men with secondary levels of education had the greatest RD (-1.9%; -3.3, -0.5%). Comparisons between the participants and the inferred sample revealed few differences.

Conclusions

All RD between the inferred and gold standard samples lie within our ±5% acceptability limits, in support of the use of our methodology for adjusting for non-participation in health surveys. However, under MAR, there are no significant differences between the results generated from the inferred sample and the participants alone. Further work exploring Missing Not At Random scenarios is required to ensure utility for reliable population health monitoring.

Key messages

Survey weights alone cannot adjust for non-representativeness, but we have shown that data linkage can be used to match the characteristics and outcomes of the selected sample. Non-participation in health surveys may be adjusted for using our methodology, with further exploration into alternative missing data scenarios required.

Towards patterned bioelectronics: facilitated immobilization of exoelectrogenic Escherichia coli with heterologous pili

Biosensors detect signals using biological sensing components such as redox enzymes and biological cells. Although cellular versatility can be beneficial for different applications, limited stability and efficiency in signal transduction at electrode surfaces represent a challenge. Recent studies have shown that the Mtr electron conduit from Shewanella oneidensis MR-1 can be produced in Escherichia coli to generate an exoelectrogenic model system with well-characterized genetic tools. However, means to specifically immobilize this organism at solid substrates as electroactive biofilms have not been tested previously. Here, we show that mannose-binding Fim pili can be produced in exoelectrogenic E. coli and can be used to selectively attach cells to a mannose-coated material. Importantly, cells expressing fim genes retained current production by the heterologous Mtr electron conduit. Our results demonstrate the versatility of the exoelectrogenic E. coli system and motivate future work that aims to produce patterned biofilms for bioelectronic devices that can respond to various biochemical signals.

Cooperative activation of transcription by autoimmune regulator AIRE and CBP

Autoimmune regulator (AIRE) is a transcriptional regulator that is believed to control the expression of tissue-specific genes in the thymus. Mutated AIRE is responsible for onset of the hereditary autoimmune disease APECED. AIRE is able to form nuclear bodies (NBs) and interacts with the ubiquitous transcriptional coactivator CBP. In this paper, we show that CBP and AIRE synergistically activate transcription on different promoter reporters whereas AIRE gene mutation R257X, found in APECED patients, interferes with this coactivation effect. Furthermore, the overexpression of AIRE and CBP collaboratively enhance endogenous IFNbeta mRNA expression. The immunohistochemical studies suggest that CBP, depending on the balance of nuclear proteins, is a component of AIRE NBs. We also show that AIRE NBs are devoid of active chromatin and, therefore, not sites of transcription. In addition, we demonstrate by 3D analyses that AIRE and CBP, when colocalizing, are located spatially differently within AIRE NBs. In conclusion, our data suggest that AIRE activates transcription of the target genes, i.e., autoantigens in collaboration with CBP and that this activation occurs outside of AIRE NBs.

Lower Limb Amputations in Southern Finland in 2000 and Trends up to 2001

OBJECTIVES

To assess the current incidence of major lower limb amputations in Southern Finland and epidemiological trends during the last 17 years.

MATERIALS AND METHODS

In a retrospective survey for the year 2000 patient data was gathered from hospital records in the eight surgical hospitals in the area studied. Follow-up was 1 year. Amputation data for years 1984-1995 was gathered from reports done before at the same area and amputation figures for years 1990-2001 also from the National Research and Development Centre for Welfare and Health.

RESULTS

In year 2000, the incidence of major amputations was 154/million inhabitants. The reason for major amputation was chronic critical lower limb ischaemia in 71.8% and acute ischaemia in 16.5% of the cases. The below-knee (BK)/above-knee (AK) ratio was 0.76. After 1 year only 48% of the patients were alive. From 1984 to 2000 amputation incidence showed a decrease of 41%. The decline in age-adjusted amputation incidence from 1990 to 2000 was 30% and by 2001 as much as 40%. There was a significant inverse correlation both between incidence of infrainguinal bypass and amputation (r=-0.682, p=0.021) and between infrapopliteal bypass and amputation (r=-0.682, p=0.021).

CONCLUSIONS

There was a reduction in the number of amputations in Southern Finland during the past 17 years. This occurred synchronously with the increase in vascular reconstructions. Our data suggests that vascular surgery saves patients from BK-amputations and therefore relative amount of AK-amputations inevitably rises.

Autoimmune regulator: from loss of function to autoimmunity

The autoimmune regulator (AIRE) is a gene where mutations cause the recessively inherited disorder called autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) or autoimmune polyendocrinopathy syndrome type 1 (APS1). Variable combinations of autoimmune endocrine diseases such as Addison's disease, hypoparathyroidism, and type 1 diabetes characterize APECED. The AIRE protein has several domains indicative of a transcriptional regulator. AIRE contains two PHD (plant homeodomain) type zinc fingers, four nuclear receptor binding LXXLL motifs, a putative DNA-binding domain named SAND and, in addition, a highly conserved N-terminal domain similar to the homogenously staining region domain of the Sp100 protein. At the subcellular level, AIRE is expressed in nuclear dots resembling promyelocytic leukemia nuclear bodies, which are associated with several transcriptionally active proteins. AIRE is primarily expressed in thymic medullary epithelial cells and monocyte-dendritic cells in the thymus but also in a rare subset of cells in the lymph nodes, spleen and fetal liver. The disease, caused by mutations in AIRE, its function as a protein involved in transcription, and its restricted expression in cells important in negative selection, all together suggest that AIRE is a central protein in the maintenance of immune tolerance. In this review of the recent literature we discuss the results of these studies with particular attention on the AIRE expression pattern and its function as a transcriptional regulator, as well as the effects of patient mutations on the molecular characteristics of the protein.

Subcellular localization of the autoimmune regulator protein. characterization of nuclear targeting and transcriptional activation domain

The autoimmune regulator (AIRE) gene, defective in the hereditary autoimmune disease APECED, encodes a transcriptional regulator protein. AIRE is expressed in the medullary epithelial cells and monocyte-dendritic cells of the thymus with lower expression in the spleen, fetal liver, and lymph nodes. At the cellular level, AIRE is located in microtubular structures of the cytoskeleton and in discrete nuclear dots resembling ND10 nuclear bodies. We studied the determinants of the targeting of AIRE into these structures. We report here that the N-terminal HSR domain confers localization to the microtubular network whereas the C-terminal region contains a second nuclear localization signal. We also demonstrate that the consensus nuclear localization signal of AIRE is functional and that the HSR domain harbors a nuclear export signal. Accordingly, the nuclear export inhibitor leptomycin B partially inhibits the nuclear export of AIRE. From a functional standpoint, we show that AIRE can activate the interferon beta minimal promoter in a transfection assay and demonstrate that the transcriptional activating function of AIRE is mediated by its two plant homeodomain (PHD) zinc fingers.

DNA vaccination in mice using HIV-1 nef, rev and tat genes in self-replicating pBN-vector

The immunogenicity of a self-replicating DNA-vector containing HIV-1 nef gene (pBN-Nef) was characterized using various DNA delivery methods. In addition, gene gun immunisation was used for assessing immunogenicity of two other HIV-1 genes (rev and tat) given in the same vector. The pBN-Nef was the most immunogenic raising both humoral and cell-mediated immune responses in mice; these responses lasted for up to six months. The pBN-Nef vector was immunogenic also when given intramuscularly or intradermally. The pBN-Rev construct did not elicit humoral responses but did elicit proliferative as well as CTL-response against the corresponding protein. The pBN-Tat was a poor immunogen in all respects. The antibodies elicited with various DNA delivery methods belonged to different antibody subclasses; however, two main epitopes in Nef were frequently recognized by all of them.

The autoimmune regulator protein has transcriptional transactivating properties and interacts with the common coactivator CREB-binding protein

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy, caused by mutations in the autoimmune regulator (AIRE) gene, is an autosomal recessive autoimmune disease characterized by the breakdown of tolerance to organ-specific antigens. The 545 amino acid protein encoded by AIRE contains several structural motifs suggestive of a transcriptional regulator and bears similarity to cellular proteins involved in transcriptional control. We show here that AIRE fused to a heterologous DNA binding domain activates transcription from a reporter promoter, and the activation seen requires the full-length protein or more than one activation domain. At the structural level AIRE forms homodimers through the NH(2)-terminal domain, and molecular modeling for this domain suggests a four-helix bundle structure. In agreement, we show that the common transcriptional coactivator CREB-binding protein (CBP) interacts with AIRE in vitro and in yeast nuclei through the CH1 and CH3 conserved domains. We suggest that the transcriptional transactivation properties of AIRE together with its interaction with CBP might be important in its function as disease-causing mutations almost totally abolish the activation effect.

Does saphenous vein arterialisation prevent major amputation in critical leg ischaemia? A comparative study

BACKGROUND

Arterialisation of the great saphenous vein has been suggested to improve distal circulation in patients with critical leg ischaemia not accessible for reconstructive surgery. As the technique has been a matter of controversy the aim was to assess the outcome of a series of own patients treated with arterialisation and compare them with conservatively treated patients.

METHODS

EXPERIMENTAL DESIGN

a retrospective cohort study.

SETTING

an academic referral centre (Department of Surgery, Helsinki University Central Hospital) together with a district hospital (Peijas-Rekola Hospital).

PATIENTS AND INTERVENTIONS

14 consecutive patients with critical leg ischaemia treated with arterialisation of the great saphenous vein in the district hospital were compared with 14 age, sex, diabetes and symptom severity-matched controls with critical leg ischaemia treated conservatively in the academic referral centre.

MEASURES

major amputations and patient survival.

RESULTS

The leg salvage rate was 57% at one year in the arterialisation group and 54% in the conservative group (NS) but the survival rate at one year was 92% in the operative group and 64% in the control group (NS).

CONCLUSIONS

Arterialisation did not have any effect on leg salvage. The results of this study do not support the use of arterialisation as a treatment for critical leg ischaemia

Humoral and cellular immune responses to HIV-1 nef in mice DNA-immunised with non-replicating or self-replicating expression vectors

OBJECTIVE

HIV accessory protein Nef is expressed early in the infectious cycle of the virus and has been shown to be an effective immunogen in humoral and cellular immune responses. We have used two different self-replicating pBN vectors and one non-replicating pCGal2 derived (pCG) vector expressing HIV-1 Nef in DNA immunisation of mice in order to determine their efficiency in raising humoral and cellular immune responses.

DESIGN AND METHODS

The expression of Nef by the three plasmids was tested by transfections into COS-1 cells. Balb/c mice were immunised with the pBN-NEF and pCGE2-NEF constructs using gold particle bombardment. Immunoblotting and immunocytochemistry were used to detect in vitro expression of Nef. 51Cr release assay, ELISA and immunoblotting were used to detect cellular and humoral immune responses in immunised mice.

RESULTS

Efficient in vitro expression of Nef was detected in pBN and pCGE2-NEF transfected cells, in pBN-NEF transfected cells the expression lasting up to three weeks. Anti-Nef antibodies in sera of 13 of 16 pBN-NEF immunised mice were detected within four weeks after the last immunisation, whereas only 2 of 12 pCGE2-NEF immunised mice had very weak anti-Nef antibodies. Twelve of the pBN-NEF immunised mice (75%) and 6 the pCGE2-NEF immunised mice (50%) showed Nef-specific cytotoxic T lymphocyte (CTL) responses within four weeks.

CONCLUSIONS

We conclude that the three eukaryotic expression vectors tested are capable of inducing a cell mediated immune response towards HIV-1 Nef and should be considered as part of a genetic HIV vaccine.

Acute gastric mucosal lesions, haemodynamic and microcirculatory changes in the thermally injured rat

Early postburn changes in central haemodynamics, organ blood flow distribution and morphology of the gastric mucosa were studied using a standarized thermal skin injury model. Organ blood flow and cardiac output were determined using radioactive microspheres. In the control animals no marked changes in cardiac output or organ blood flow were observed, and the gastric mucosa remained essentially undamaged. After burn injury and no fluid resuscitation, cardiac output decreased by 78 per cent, and blood flow to the stomach, pancreas, spleen, muscle, skin and kidneys also decreased markedly and to about the same degree as the cardiac output, however the adrenal flow remained roughly unchanged at the baseline level. Gross and microscopic lesions developed in the stomach, especially in the corpus. In animals given fluid resuscitation after burn injury cardiac output decreased by 38 per cent during the experiment, but blood flow in the stomach, brain, kidneys and spleen remained fairly constant, while pancreatic and muscle blood flow decreased and adrenal blood flow increased markedly. The gastric mucosa showed only minor microscopic, but no macroscopic lesions at the end of the experiment. The results indicate that acute thermal skin injury induces profound changes in central haemodynamics and organ blood flow which can, however, largely be overcome by adequate fluid resuscitation. The data also suggest that, as in other examples of 'stress ulceration', impaired mucosal blood flow may underlie the stress ulceration which complicates severe burns.

Altered polymorphonuclear neutrophilic granulocyte functions in patients with large burns

Multiparameter flow cytometric analyses of polymorphonuclear neutrophilic granulocyte (PMNL) functions have been performed longitudinally in ten patients with large burns. The percentage of phagocytosing PMNLs was increased at admission (within 24 hours after injury) and through the first 10 days of hospitalization. The surface binding capacity and the ingestion of Staphylococcus aureus by each PMNL was increased during the same time period, and at day 2 the number of S. aureus ingested per patient PMNL was 35% higher than in the controls. The intracellular killing of Candida albicans was reduced by about 25% at admission. The microbicidal capacity was further compromised during the first 2 weeks after injury, with a reduction of intracellular killing of about 35% 5-10 days after admission. The kinetics of patient PMNL phagolysosomal acidification was altered during the first 20 days, as the initial alkalinization of the phagolysosomes documented in control PMNLs could not be demonstrated in PMNLs from patients with burns. In addition, measurements of maximal phagolysosomal acidification showed a lower pH in patient phagolysosomes than in the controls during the first 5 days. The patient PMNL H2O2 production was reduced at admission and through the first 10 days, with an oxidative burst that was 46% lower than the controls at day 5. The intracellular degradation of S. aureus proteins and DNA was slightly but significantly reduced at day 5 and day 10 after admission. The impairment of PMNL microbicidal capacity correlated with total body surface area burn.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcapillary colloid osmotic pressures in injured and non-injured skin of seriously burned patients

Thermal skin injury is accompanied by rapid and excessive oedema formation implicating a dramatic increase in the transcapillary fluid transport. In order to clarify the pressure changes occurring across the microvasculature after a thermal skin injury we have measured colloid osmotic pressures (COP) in interstitial fluid (COPi) of injured and non-injured skin as well as in plasma (COPp) from patients suffering major cutaneous burns. Interstitial fluid was collected with a wick-technique and analysed for COP. Measurements were performed as early as 6 h and continued until 56 h after injury. A severe hypoproteinaemia occurred in all patients with a marked reduction in COPp down to about 10 mmHg. Up to 12h post-burn we found a higher COPi in injured skin than in plasma. The first measurement of COPp averaged 9.8 mmHg as compared to an average COPi of 11.1 and 9.3 mmHg in injured and non-injured skin respectively. Measurements performed later than 12h showed a return of the transcapillary COP gradient towards the normal direction (COPp greater than COPi). The gradient was considerably less than in a normal situation. Based on the present observations of transcapillary COP it is suggested that colloids should be withheld until the transcapillary COP gradient returns to the normal direction.

Carcinoma of the lip. A retrospective study of 70 patients

From 1966 to 1978, 70 patients with carcinoma of the lip were treated at the Division of Plastic Surgery, University Central Hospital, Helsinki. The lip tumour was a squamous cell carcinoma in 64 patients, and a basal cell carcinoma in 6 patients. Of these 70 patients, 24 had radiotherapy as the primary mode of therapy and 46 patients had been treated initially by surgery. The results of surgery were generally good. However, in the group of "simple wedge excision" and in patients who had had radiotherapy as the primary treatment there was a higher incidence of recurrences. In the former group the recurrences were considered to be due to a too narrow angle of excision. We recommend surgery as the primary method of treatment because of the availability of histologically accurate tumour margin assessment, the short rehabilitation period and the good functional results achieved.

Microvascular free flaps in early reconstruction of burns in the hand and forearm. Case reports

In the reconstructive plastic surgery a free flap provides a one-stage method to achieve an optimal functional an aesthetic result. We report five acute burns or early contractions of the hand and forearm with free-flap reconstruction. In each case an attempt was made to design the flap to restore missing tissue components. We used three different musculocutaneous free flaps and two free skin flaps: a latissimus dorsi, a rectus abdominis and a rectus femoris renervated musculocutaneous flap, as well as a dorsalis pedis and a horizontal fasciocutaneous upper arm flap. In all five cases, the hand and wrist showed early restoration of function.

Adriamycin extravasation: surgical treatment and possible prevention of skin and soft-tissue injuries

In a material consisting of approximately 6,000 injections of Adriamycin during a 2-year period, eleven moderate and five severe extravasation injuries have been observed. Even a small leakage of the drug may cause a permanent lesion. The most serious injuries were caused by large doses and on the dorsum of the hand. Plastic surgical operations were successfully performed in the severe cases. An active surgical intervention after primary neutralization of the extravasated Adriamycin is recommended.

Neuroendocrine carcinoma of the skin (Merkel cell carcinoma): ultrastructural and immunohistochemical demonstration of neurofilaments

In this study we characterized a skin tumor that grew in the temporal region of a 69-year-old woman. On the basis of tumor morphology, a metastasis from a small cell carcinoma of the lung was initially suggested, but X-ray and bronchoscopic studies were negative. The tumor recurred twice within a year, yet no tumors were found elsewhere in the body. Ultrastructurally, cytoplasmic organelles compatible with neuroendocrine storage granules and perinuclear aggregates of intermediate-sized (8-10 nm) filaments were found in many tumor cells. Indirect immunofluorescence microscopy revealed neurofilament-type intermediate filaments in the tumor cells but no keratin- or vimentin-type filaments. Our results further demonstrate neural properties of this tumor type, which is generally considered to have its origin from Merkel cells, the cutaneous neuroendocrine cells.