Accuracy of Three Commercial Home-Use Hemoglobin A1c Tests

Background: The COVID-19 pandemic and the rapid expansion of telemedicine have increased the need for accurate and reliable capillary hemoglobin A1c (HbA1c) testing. Nevertheless, validation studies of commercially available products suitable for home use have been in short supply. Methods: Three commercial home-use capillary blood sample HbA1c tests (Home Access, CoreMedica, and A1cNow+) were evaluated in 219 participants with type 1 or type 2 diabetes (4-80 years years of age, HbA1c 5.1%-13.4% [32-123 mmol/mol]) at four clinical sites. Comparisons were made between HbA1c measurements from the commercial tests and paired venous samples for which HbA1c was measured at two central reference laboratories. The primary outcome was percentage of commercial HbA1c values within 5% of the corresponding reference values. Results: HbA1c values were within 5% (relative difference) of paired reference values for 82% of Home Access samples, 29% of CoreMedica samples, and 46% of A1cNow+ samples. Absolute differences were within 0.3% of the reference value for 75% of Home Access samples, 28% of CoreMedica samples, and 44% of A1cNow+ samples and exceeded 0.5% for 8%, 55%, and 37%, respectively. Conclusions: None of the commercial home-use HbA1c tests produced the National Glycohemoglobin Standardization Program goal of ≥90% measurements within 5% of a DCCT venous reference. However, the Home Access product performed substantially better than the CoreMedica or A1cNow+ products. Telemedicine is likely to persist as a mainstay of diabetes care well after the COVID-19 era. As such, accurate home-based HbA1c assessment represents an urgent need for the diabetes community.

An Evaluation of Two Capillary Sample Collection Kits for Laboratory Measurement of HbA1c

Background: The COVID-19 pandemic has impacted the conduct of clinic visits. We conducted a study to evaluate two academic laboratories' fingerstick capillary blood collection kits suitable for home use for laboratory measurement of HbA1c. Methods: Four clinical sites recruited 240 participants (aged 4-80 years, HbA1c 5.1%-13.5%). Capillary blood samples were obtained by the participant or parent using collection kits from two laboratories (University of Minnesota Advanced Research and Diagnostic Laboratory (ARDL) and Children's Mercy Hospital Laboratory (CMH)) and mailed under varying shipping conditions by United States Postal Service to the laboratories. Comparisons were made between HbA1c measurements from capillary samples and contemporaneously obtained venous samples. The primary outcome was percentage of capillary HbA1c values within 5% of the corresponding venous values. Results: HbA1c values were within 5% of venous values for 96% of ARDL kit specimens shipped with a cold pack and 98% without a cold pack and 99% and 99%, respectively, for the CMH kits. R² values were 0.98, 0.99, 0.99, and 0.99, respectively. Results appeared similar across HbA1c levels and for pediatric and adult participants. Usability survey scores were high. Conclusions: Capillary blood collection kits, suitable for home use, from two academic laboratories, were demonstrated to be easy to use and provided results that are comparable with those obtained from venous specimens. Based on these results, there is strong evidence that HbA1c measurements from capillary specimens obtained with these specific kits can be used interchangeably with HbA1c measurements from venous specimens for clinical research and clinical care.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Long-term excess risk of stroke in people with Type 2 diabetes in Sweden according to blood pressure level: a population-based case-control study

AIMS

To estimate the risk of stroke in people with Type 2 diabetes with different blood pressure levels compared with the risk in the general population in Sweden.

METHODS

This prospective case-control study included 408 076 people with Type 2 diabetes, aged ≥ 18 years, and free of prior stroke, registered in the Swedish National Diabetes Register 1998-2011. Age- and sex-matched control subjects (n = 1 913 507) without stroke from the general population were included. Stroke diagnoses were retrieved using International Classification of Disease codes from the Swedish patient and death registers. Cox hazard ratios and 95% confidence intervals (CIs) were estimated at six different blood pressure levels.

RESULTS

During a median follow-up of 4 years, 19 548 (4.8%) people with Type 2 diabetes and 61 690 (3.2%) without diabetes were diagnosed with stroke, corresponding to an adjusted hazard ratio of 1.43 (95% CI 1.41-1.46) for people with Type 2 diabetes as a group. Compared with people without diabetes, the risk of stroke for people with Type 2 diabetes with different blood pressure levels was significantly higher, starting at blood pressure levels > 130/80 mmHg. Hazard ratios for stroke were 1.20 (95% CI 1.16-1.24), 1.47 (95% CI 1.43-1.50), and 1.97 (95% CI 1.90-2.03) for blood pressure categories of 130-139/80-89 mmHg, 140-159/90-99 mmHg and ≥ 160/≥ 100 mmHg, respectively, after adjustment for age, sex, diabetes duration, being born in Sweden, maximum education level and baseline comorbidities.

CONCLUSIONS

People with Type 2 diabetes and blood pressure < 130/80 mmHg had a risk of stroke similar to that of the general population.

Prostate cancer screening in men aged 50 to 69 years (STHLM3): A prospective population-based diagnostic study. Grönberg H, Adolfsson J, Aly M, Nordström T, Wiklund P, Brandberg Y, Thompson J, Wiklund F, Lindberg J, Clements M, Egevad L, Eklund M.Lancet Oncol. 2015 Dec;16(16):1667-76. [Epub 2015 Nov 10]. doi: 10.1016/S1470-2045(15)00361-7

BACKGROUND

The prostate-specific antigen (PSA) test is used to screen for prostate cancer but has a high false-positive rate that translates into unnecessary prostate biopsies and overdiagnosis of low-risk prostate cancers. We aimed to develop and validate a model to identify high-risk prostate cancer (with a Gleason score of at least 7) with better test characteristics than that provided by PSA screening alone.

METHODS

The Stockholm 3 (STHLM3) study is a prospective, population-based, paired, screen-positive, diagnostic study of men without prostate cancer aged 50 to 69 years randomly invited by date of birth from the Swedish Population Register kept by the Swedish Tax Agency. Men with prostate cancer at enrolment were excluded from the study. The predefined STHLM3 model (a combination of plasma protein biomarkers [PSA, free PSA, intact PSA, hK2, MSMB, MIC1], genetic polymorphisms [232 SNPs], and clinical variables [age, family, history, previous prostate biopsy, prostate exam]), and PSA concentration were both tested in all participants enrolled. The primary aim was to increase the specificity compared with PSA without decreasing the sensitivity to diagnose high-risk prostate cancer. The primary outcomes were number of detected high-risk cancers (sensitivity) and the number of performed prostate biopsies (specificity). The STHLM3 training cohort was used to train the STHLM3 model, which was prospectively tested in the STHLM3 validation cohort. Logistic regression was used to test for associations between biomarkers and clinical variables and prostate cancer with a Gleason score of at least 7. This study is registered with ISCRTN.com, number ISRCTN84445406.

FINDINGS

The STHLM3 model performed significantly better than PSA alone for detection of cancers with a Gleason score of at least 7 (P<0.0001), the area under the curve was 0·56 (95% CI: 0·55-0·60) with PSA alone and 0·74 (95% CI: 0·72-0·75) with the STHLM3 model. All variables used in the STHLM3 model were significantly associated with prostate cancers with a Gleason score of at least 7 (P<0·05) in a multiple logistic regression model. At the same level of sensitivity as the PSA test using a cutoff of≥3ng/ml to diagnose high-risk prostate cancer, use of the STHLM3 model could reduce the number of biopsies by 32% (95% CI: 24-39) and could avoid 44% (35-54) of benign biopsies.

INTERPRETATION

The STHLM3 model could reduce unnecessary biopsies without compromising the ability to diagnose prostate cancer with a Gleason score of at least 7, and could be a step towards personalised risk-based prostate cancer diagnostic programmes.

FUNDING

Stockholm County Council (Stockholms Läns Landsting).

Abstract P1-07-22: Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis

Background: Infection-related hospitalizations are a serious complication in breast cancer patients, resulting in treatment delay, prolonged hospitalization and future morbidity and mortality. Little, however, is known about the actual risk, clinical characteristics and outcomes of infection-related hospitalizations in this patient population.

Methods: We conducted a prospective population-based study including 7071 women diagnosed with primary invasive non-metastatic breast cancer between 2001 and 2008 in the Stockholm-Gotland region (Sweden), with complete follow-up until 2010. Standardized incidence ratios (SIRs) for infection-related hospitalizations (overall and by site) were estimated using background rates from the general female population, matched on age and calendar period. Associations with clinical characteristics and breast cancer outcomes (breast cancer death, distant metastasis and locoregional recurrence) were analysed using flexible parametric survival models.

Results: During a medium follow-up of 5.3 years, 657 hospital admissions with infections were observed and 1,2 and 5-year cumulative risks were 3.4, 4.7 and 8.1% respectively. Rates of infection-related hospitalizations were increased compared to the general female population (SIR = 2.12; 95% CI = 1.96-2.29) and site-specific SIRs were most pronounced for sepsis (SIR = 3.65; 95% CI = 3.13-4.26) and skin infections (SIR = 2.93; 95% CI = 2.35-3.64). The overall risk of infections was highest during the first year (SIR = 5.06; 95% CI, 4.46-5.74), and recurrent disease contributed to the long-term risk observed. Older age at diagnosis, chemotherapy, axillary radiotherapy, comorbidities and markers of tumor aggressiveness (large tumors, estrogen receptor negative tumors and lymph node positive tumors) were independent predictors of infectious disease risk. Analyses evaluating the prognostic impact of infections revealed an independent effect on breast cancer death and distant metastasis, associations that were mainly driven by sepsis (HR = 4.53; 95% CI, 3.25-6.33 and 1.69; 95% CI, 1.04-2.79 respectively). No association was found with future risk of locoregional recurrence.

Conclusions: Physicians and patients should be aware of the risk of serious infections which persists beyond the initial treatment period. Infection-related hospitalizations are an independent marker of poor prognosis. Further research is needed to elucidate the role of sepsis in breast cancer progression.

Citation Format: Brand JS, Colzani E, Johansson A, Giesecke J, Clements M, Bergh J, Hall P, Czene K. Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-22.

Type and quantity of data needed for an early estimate of transmissibility when an infectious disease emerges

An early estimate of disease transmissibility is essential for a well-informed public health response to a newly emerged infectious disease. In this study, we ask what type and quantity of data are needed for useful estimation of the initial reproduction number (R). It is possible to estimate R from case incidence data alone when the growing incidence of cases displays a wave pattern, because the pattern provides information about the serial interval (the time elapsed between the onset of symptoms of a case and symptom onset in individuals infected by that case). When the mode of the serial interval distribution is small, 1.5 days or less, there is generally no informative wave pattern in the observed series of daily incidences. The precision of the estimate of R is then improved substantially by having some observations on the serial interval. For an infectious disease with characteristics such as those of influenza, an estimate of R able to inform plans to mitigate transmission is obtained when the cumulative incidence of cases reaches about 300 and about 10 observations on the serial interval are available.

Type and quantity of data needed for an early estimate of transmissibility when an infectious disease emerges

An early estimate of disease transmissibility is essential for a well-informed public health response to a newly emerged infectious disease. In this study, we ask what type and quantity of data are needed for useful estimation of the initial reproduction number (R). It is possible to estimate R from case incidence data alone when the growing incidence of cases displays a wave pattern, because the pattern provides information about the serial interval (the time elapsed between the onset of symptoms of a case and symptom onset in individuals infected by that case). When the mode of the serial interval distribution is small, 1.5 days or less, there is generally no informative wave pattern in the observed series of daily incidences. The precision of the estimate of R is then improved substantially by having some observations on the serial interval. For an infectious disease with characteristics such as those of influenza, an estimate of R able to inform plans to mitigate transmission is obtained when the cumulative incidence of cases reaches about 300 and about 10 observations on the serial interval are available.

Does Children's Academic Achievement Improve when Single Mothers Marry?

Promoting marriage, especially among low-income single mothers with children, is increasingly viewed as a promising public policy strategy for improving developmental outcomes for disadvantaged children. Previous research suggests, however, that children's academic achievement either does not improve or declines when single mothers marry. In this paper, we argue that previous research may understate the benefits of mothers' marriages to children from single-parent families because (1) the short-term and long-term developmental consequences of marriage are not adequately distinguished and (2) child and family contexts in which marriage is likely to confer developmental advantages are not differentiated from those that do not. Using multiple waves of data from the ECLS-K, we find that single mothers' marriages are associated with modest but statistically significant improvements in their children's academic achievement trajectories. However, only children from more advantaged single-parent families benefit from their mothers' marriage.

The dynamics of life stressors and depressive symptoms in early adolescence: a test of six theoretical models

Structural equation modeling was used to compare 6 competing theoretically based psychosocial models of the longitudinal association between life stressors and depressive symptoms in a sample of early adolescents (N= 907; 40% Hispanic, 32% Black, and 19% White; mean age at Time 1 = 11.4 years). Only two models fit the data, both of which included paths modeling the effect of depressive symptoms on stressors recall: The mood-congruent cognitive bias model included only depressive symptoms to life stressors paths (DS-->S), whereas the fully transactional model included paths representing both the DS-->S and stressors to depressive symptoms (S-->DS) effects. Social causation models and the stress generation model did not fit the data. Findings demonstrate the importance of accounting for mood-congruent cognitive bias in stressors-depressive symptoms investigations.

Putative human liver progenitor cells in explanted liver

BACKGROUND/AIMS

Hepatocyte progenitors have frequently been cultured from rodents but reports from human liver are rare.

METHODS

Non-parenchymal cell fraction isolated from 19 explant livers (removed at orthotopic liver transplantation for acute or chronic liver disease) and histologically normal human liver was cultured.

RESULTS

Proliferating epithelioid colonies were identifiable after 2-3 weeks culture as a very rare event (<1 per million cells plated) expressing mRNAs and protein antigens of mixed hepatocytic/biliary phenotype. Colony survival could be prolonged by transduction of the catalytic sub-unit of telomerase. Hepatocyte growth factor, epidermal growth factor and oncostatin M did not further enhance hepatocytic differentiation. The expression of markers associated with hepatocyte precursor status was investigated by flow cytometry. Cells expressing the stem cell-associated markers CD133 and CD117 were identified at low frequency. The proportion of cells expressing the integrin CD49f was higher in diseased liver than in normal liver, but the proportion expressing the hepatocyte growth factor receptor c-met was lower. Successful enrichment of plated populations for progenitors was not achieved.

CONCLUSION

Although there is clear histological evidence of hepatocyte precursors in human explant livers, predictable culture of such cells with differentiation toward mature hepatocyte phenotype remains elusive.

Predicting case numbers during infectious disease outbreaks when some cases are undiagnosed

We describe a method for calculating 95 per cent bounds for the current number of hidden cases and the future number of diagnosed cases during an outbreak of an infectious disease. A Bayesian Markov chain Monte Carlo approach is used to fit a model of infectious disease transmission that takes account of undiagnosed cases. Assessing this method on simulated data, we find that it provides conservative 95 per cent bounds for the number of undiagnosed cases and future case numbers, and that these bounds are robust to modifications in the assumptions generating the simulated data. Moreover, the method provides a good estimate of the initial reproduction number, and the reproduction number in the latter stages of the outbreak. Applying the approach to SARS data from Hong Kong, Singapore, Taiwan and Canada, the bounds on future diagnosed cases are found to be reliable, and the bounds on hidden cases suggests that there were few hidden cases remaining at the end of the outbreaks in each region. We estimate that the initial reproduction numbers lay between 1.5 and 3, and the reproduction numbers in the later stages of the outbreak lay between 0.36 and 0.6.

The relationship between fast bowling workload and injury in first-class cricketers: a pilot study

This study examined the relationship between the bowling workload of first-class fast bowlers and injury with the aim of identifying a "safe" fast bowling workload threshold. Twelve male fast bowlers (mean age 25 years) from an Australian state cricket squad were observed for the 1999--2000 cricket season. Workload was quantified by examining fixture scorecards and conducting surveillance at training sessions. Injury data were obtained from Cricket Australia's Injury Surveillance System. The seasonal incidence of injury was high with seven bowlers sustaining nine injuries. Whilst injured bowlers did not tend to bowl a greater number of deliveries on the day of injury, a significant increase in deliveries per session was observed in the 8-21 days prior to the date of injury (mean= 77) as compared with the rest of the season (mean= 60, p< 0.02). Bowlers with a weekly bowling workload above the mean of 203 deliveries were at an increased risk of injury (Risk Ratio (RR)= 6.0, 95% confidence interval (CI) 1.00-35.91). Those bowlers who bowled in five or more sessions in any 7-day period were also at an increased risk of injury (RR= 4.5, 95% CI 1.02 to 20.12). A consistent relationship between high bowling workload and injury was observed. The risk of injury was much higher for those bowlers with a sessional, weekly and monthly bowling workload above the group mean, especially when this high workload was consistent and sustained.

Benchmarking best practice for external ventricular drainage

Sharing of best practice and use of all available evidence is important in developing effective clinical guidelines for nursing practice. This can be achieved through benchmarking. Sharing of good practice and achieving consensus guidelines can avoid repetition of effort by nurses engaged in similar fields of practice. The Pan London Neuroscience Practice Development Forum was established in 1998 to share best practice within the field of neuroscience nursing across London. The Pan London Forum has now achieved consensus and developed evidence-based clinical guidelines for the management of external ventricular drainage. Within the scope of this article, the principles of external ventricular drainage will be highlighted, before identifying the evidence base for nursing management of patients. Approaches for troubleshooting common problems will also be discussed and the benchmarked clinical guidelines will be presented.

Molecular effects of novel mutations in Hesx1/HESX1 associated with human pituitary disorders

The homeobox gene Hesx1/HESX1 has been implicated in the establishment of anterior pattern in the central nervous system (CNS) in a number of vertebrate species. Its role in pituitary development has been documented through loss-of-function studies in the mouse. A homozygous missense point mutation resulting in a single amino acid substitution, Arg160Cys (R160C), is associated with a heritable form of the human condition of septo-optic dysplasia (SOD). We have examined the phenotype of affected members in this pedigree in more detail and demonstrate for the first time a genetic basis for midline defects associated with an undescended or ectopic posterior pituitary. A similar structural pituitary abnormality was observed in a second patient heterozygous for another mutation in HESX1, Ser170Leu (S170L). Association of S170L with a pituitary phenotype may be a direct consequence of the HESX1 mutation since S170L is also associated with a dominant familial form of pituitary disease. However, a third mutation in HESX1, Asn125Ser (N125S), occurs at a high frequency in the Afro-Caribbean population and may therefore reflect a population-specific polymorphism. To investigate the molecular basis for these clinical phenotypes, we have examined the impact of these mutations on the regulatory functions of HESX1. We show that Hesx1 is a promoter-specific transcriptional repressor with a minimal 36 amino acid repression domain which can mediate promoter-specific repression by suppressing the activity of homeodomain-containing activator proteins. Mutations in HESX1 associated with pituitary disease appear to modulate the DNA-binding affinity of HESX1 rather than its transcriptional activity. Wild-type HESX1 binds a dimeric homeodomain site with high affinity (Kd 31 nM) whilst HESX1(S170L) binds with a 5-fold lower activity (Kd 150 nM) and HESX1(R160C) does not bind at all. Although HESX1(R160C) has only been shown to be associated with the SOD phenotype in children homozygous for the mutation, HESX1(R160C) can inhibit DNA binding by wild-type HESX1 both in vitro and in vivo in cell culture. This dominant negative activity of HESX1(R160C) is mediated by the Hesx1 repression domain, supporting the idea that the repression domain is implicated in interactions between homeodomain proteins. Our data suggest a possible molecular paradigm for the dominant inheritance observed in some pituitary disorders.

Virulence gene regulation in Salmonella enterica

In order to infect a host, a microbe must be equipped with special properties known as virulence factors. Bacterial virulence factors are required to facilitate colonization, to survive under host defenses, and to permit multiplication inside the host. However, the possession of genes encoding virulence factors does not guarantee effective infection. There is considerable evidence that tight regulation of a given virulence factor is as important as the possession of the virulence factors themselves. Thus, an understanding of the regulation of virulence expression is fundamental to our comprehension of any infection process and can identify potential targets for disease prevention and therapy. We have summarized the lessons learned from experimental salmonellosis in terms of virulence regulation and hope to illustrate the differing requirements for gene and virulence expression.

Expression of the cysteinyl leukotriene 1 receptor in normal human lung and peripheral blood leukocytes

The cysteinyl leukotrienes (CysLTs) are important mediators of human asthma. Pharmacologic and clinical studies show that the CysLTs exert most of their bronchoconstrictive and proinflammatory effects through activation of a putative, 7-transmembrane domain, G-protein-coupled receptor, the CysLT1 receptor. The initial molecular characterization of the CysLT1 receptor showed by in situ hybridization, the presence of CysLT1 receptor messenger RNA (mRNA) in human lung smooth-muscle cells and lung macrophages. We confirmed the results of these in situ hybridization analyses for the CysLT1 receptor, and produced the first immunohistochemical characterization of the CysLT1 receptor protein in human lung. The identification of the CysLT1 receptor in the lung is consistent with the antibronchoconstrictive and antiinflammatory actions of CysLT1 receptor antagonists. We also report the expression of CysLT1 receptor mRNA and protein in most peripheral blood eosinophils and pregranulocytic CD34+ cells, and in subsets of monocytes and B lymphocytes.

Domestic fire injuries treated in New Zealand hospitals 1988-1995

AIM

To describe demographic features of people discharged from New Zealand hospitals following injury caused by fire and flame in domestic locations.

METHOD

Review of hospital discharge data for the years 1988-1995.

RESULTS

From 1988-1995 there were 1493 discharges from New Zealand hospitals with injury as the result of fire and flame in domestic locations. Age-standardised hospitalisation rates for fire related injury over the period have been stable, with an overall discharge rate of 5.45 hospitalisations per 100000 person years. Male discharges exceeded female in all years (RR 1.97, 95% CI 1.73-2.14). Stratification by age indicated that discharge rates were highest among New Zealanders aged over 75 years and under fifteen years. Maori discharge rates exceeded non-Maori over all age groups (RR 3.3, 95% CI 2.82-3.58).

CONCLUSION

Maori discharge rates for fire related injury in the home are substantially higher than non-Maori in all age groups, and highlight the importance of developing culturally appropriate injury prevention strategies. Social and material determinants of injury need to be addressed through public policy, provision of quality housing and community development initiatives.

Hex is a transcriptional repressor that contributes to anterior identity and suppresses Spemann organiser function

One of the earliest markers of anterior asymmetry in vertebrate embryos is the transcription factor Hex. We find that Hex is a transcriptional repressor that can be converted to an activator by fusing full length Hex to two copies of the minimal transcriptional activation domain of VP16 together with the flexible hinge region of the (lambda) repressor (Hex-(lambda)VP2). Retention of the entire Hex open reading frame allows one to examine Hex function without disrupting potential protein-protein interactions. Expression of Hex-(lambda)VP2 in Xenopus inhibits expression of the anterior marker Cerberus and results in anterior truncations. Such embryos have multiple notochords and disorganised muscle tissue. These effects can occur in a cell non-autonomous manner, suggesting that one role of wild-type Hex is to specify anterior structures by suppressing signals that promote dorsal mesoderm formation. In support of this idea, over-expression of wild-type Hex causes cell non-autonomous dorso-anteriorization, as well as cell autonomous suppression of dorsal mesoderm. Suppression of dorsal mesoderm by Hex is accompanied by the down-regulation of Goosecoid and Chordin, while induction of dorsal mesoderm by Hex-(lambda)VP2 results in activation of these genes. Transient transfection experiments in ES cells suggest that Goosecoid is a direct target of Hex. Together, our results support a model in which Hex suppresses organiser activity and defines anterior identity.

The homeobox gene Hex is required in definitive endodermal tissues for normal forebrain, liver and thyroid formation

The homeobox gene Hex is expressed in the anterior visceral endoderm (AVE) and rostral definitive endoderm of early mouse embryos. Later, Hex transcripts are detected in liver, thyroid and endothelial precursor cells. A null mutation was introduced into the Hex locus by homologous recombination in embryonic stem cells. Hex mutant embryos exhibit varying degrees of anterior truncation as well as liver and thyroid dysplasia. The liver diverticulum is formed but migration of hepatocytes into the septum transversum fails to occur. Development of the thyroid is arrested at the thyroid bud stage at 9.5 dpc. Brain defects are restricted to the rostral forebrain and have a caudal limit at the zona limitans intrathalamica, the boundary between dorsal and ventral thalamus. Analysis of Hex(−/−) mutants at early stages shows that the prospective forebrain ectoderm is correctly induced and patterned at 7.5 days post coitum (dpc), but subsequently fails to develop. AVE markers are expressed and correctly positioned but development of rostral definitive endoderm is greatly disturbed in Hex(−/−) embryos. Chimeric embryos composed of Hex(−/−) cells developing within a wild-type visceral endoderm show forebrain defects indicating that Hex is required in the definitive endoderm. All together, these results demonstrate that Hex function is essential in definitive endoderm for normal development of the forebrain, liver and thyroid gland.

Seasonal differences in risk factors for sudden infant death syndrome. The New Zealand Cot Death Study Group

The aim of this study was to explore whether the risk of sudden infant death syndrome (SIDS) associated with prone sleeping position and other risk factors varies with season. The study was a large nation-wide case-control study, which compared 485 cases with 1800 controls. Parents of 393 (81.0%) cases and 1591 (88.4%) controls were interviewed. Obstetric records were also examined. Infants dying in winter were older and had lower birthweights than those dying in summer. The increased risk of SIDS associated with prone sleeping position was greater in winter than in summer. In contrast, the increased risk of SIDS associated with excess thermal insulation and bed sharing was less in winter than in summer. Prone sleeping position accounts for about half of the difference between the mortality rate in summer and that in winter. This suggests that some factor related to season modifies the effect of prone sleeping position.

Ethnic differences in parent/infant co-sleeping practices in New Zealand

AIM

This study was designed to monitor changes in the prevalence of risk factors for sudden infant death syndrome (SIDS) in the New Zealand population. The behaviour of interest is parent/infant co-sleeping. This paper reports parent/infant co-sleeping arrangements of different ethnic groups in New Zealand.

METHODS

A stratified random sample of 6268 infants attending Plunket clinics for their three and six-month visits was taken over the years 1995-1996. Maori and Pacific infants were oversampled. Parents who shared a bed with their infant were asked how they arranged the babies sleeping place according to pre-coded diagrams. Routine parent/infant co-sleeping was defined as "bed sharing at least four nights over the last two weeks".

RESULTS

There were 2693 infants who shared the bed with their sleeping parents during at least one of the previous 14 nights. Of these infants, 1060 routinely shared the parents' bed. At three months, 56% of routinely co-sleeping infants slept directly in the bed, 29% slept in a raised position, 3% slept in a carrycot or basket, and 5% in other positions. At six months, 60% of the routinely co-sleeping infants slept directly in the bed with their parents, 23% slept in a raised position, 1% slept in a carrycot or basket, and 7% in other positions. There were significant differences in the co-sleeping locations by ethnicity.

CONCLUSION

There is still some ongoing dispute as to whether parent/infant co-sleeping is a risk factor for SIDS. This study has identified differences in the way infants co-sleep with their parents and this can be used to clarify infant care practices in relation to SIDS.

Do differences in the prevalence of risk factors explain the higher mortality from sudden infant death syndrome in New Zealand compared with the UK?

AIMS

To compare the prevalence of risk factors for the sudden infant death syndrome (SIDS) in New Zealand (SIDS mortality 3.53/1000) with that in the South West Thames (SWT) region of the United Kingdom (SIDS mortality 1.36/1000).

METHODS

The methodology of the study was essentially identical in New Zealand and SWT. The subjects in both countries were randomly selected from all births in the study regions. The subjects were randomly allocated an age at which to be interviewed using the same questionnaire in the two study areas. Obstetric records were also examined. Eighteen hundred subjects were selected in New Zealand and 700 subjects in SWT.

RESULTS

Younger and unmarried mothers were slightly more common in New Zealand than in SWT. The prevalence of maternal smoking, prone sleeping position and infants' sharing of beds with another person were all higher in New Zealand than SWT, thus increasing the risk of SIDS (maternal smoking in pregnancy: 31.0% vs 23.8% respectively, chi 2 = 11.6, p = 0.001; prone sleeping position: 32.9% vs 25.9%, chi 2 = 18.9, p < 0.001; bed sharing: 10.5% vs 6.8%, chi 2 = 6.0, p = 0.14). However, New Zealand infants were breast fed more frequently and for longer than infants in SWT, which would tend to reduce the risk of SIDS in the New Zealand population. In combination the differences in the prevalences of these four risk factors explain only 20% of the excess risk of SIDS in New Zealand.

CONCLUSIONS

The high SIDS mortality rate in New Zealand is not simply explained by a high prevalence of known and modifiable risk factors for SIDS.

Marital status and births after losing a baby from sudden infant death

To describe the change in marital status and subsequent live births of mothers who have lost a baby from sudden infant death (SID or cot death), a postal questionnaire was sent to European mothers who had been interviewed approximately 3.7 years (range 2.2-5.2 years) previously as part of a nationwide case-control study. Mothers of 105 (60.3%) cases and 828 (76.9%) controls replied. Changes in marital status between the time of interview and the time of the postal questionnaire did not differ between mothers of cases and that of controls when adjusted for marital status at the time of death/nominated date for controls. Cases were more likely to have further children than controls (P < 0.001) and had them sooner after the death than after the nominated date for control babies (P < 0.001). Case mothers were more likely than controls to have a second child after the death/nominated date, however the interval between the first and second child after the death/nominated date was the same as that for controls.

CONCLUSIONS

Although the death of an infant is a major stress on marital relationships, at approximately 3.7 years marital breakdown is no higher than in the control population. After the death of her baby the mother "replaces" the child by having more children than control mothers and having the first one earlier than control mothers. Mothers who lose a baby from SID are more fertile than the control population both before and after the death.

Soft cot mattresses and the sudden infant death syndrome

AIMS

To investigate whether soft cot mattresses are a risk factor for the sudden infant death syndrome (SIDS).

METHODS

A follow up postal questionnaire was sent to the subjects who were interviewed 3.8 years (range 2.2 to 5.2 years) previously as part of the New Zealand Cot Death Study, a large nationwide case-control study.

RESULTS

105 European SIDS cases were compared with 828 European controls. Soft cot mattresses were associated with an increased risk of SIDS (adjusted OR = 2.36; 95% CI = 1.06, 5,25) compared with average or hard mattresses. The firmness of the mattress did not interact with the sleeping position of infant.

CONCLUSIONS

Soft cot mattresses should be avoided.

Partial characterization of an immortalized human trophoblast cell-line, TCL-1, which possesses a CSF-1 autocrine loop

Many previous studies in both mouse and human placenta have implicated a role for colony stimulating factor-1 (CSF-1) in the regulation of placental development. In this study we have examined CSF-1 production by an immortalized cell line (TCL-1) derived from the choriodecidua, transfected with a retrovirus gene coding for the large-T antigen. TCL-1 cells were uniformly positive by immunocytochemistry for the composite sub-units of human chorionic g gonadotrophin (hCG) but were negative for markers of other cell types localized at the fetal-maternal interface. Gelatinase enzymes were secreted by TCL-1 cells cultured on extracellular matrix in a manner indicative of extra-villous trophoblast. Dot-blot immunoassays and ELISA indicated that CSF-1 was secreted by TCL-1 cells, at levels comparable to primary trophoblast cells and BeWo choriocarcinoma (trophoblast tumour) cells. Reverse transcriptase-polymerase chain reaction analysis confirmed the presence in TCL-1 cells of CSF-1 receptor mRNA (c-fms gene product), indicating that the components of a potential autocrine loop were present in these cells. Proliferation of TCL-1 cells was not affected by the addition of exogenous CSF-1 but was elevated in response to treatment with a CSF-1 neutralizing antibody. The immortalized cell line, TCL-1, provides a potential model in which to investigate regulation of growth and differentiation of trophoblast cells in vitro.

Immunisation and the sudden infant death syndrome. New Zealand Cot Death Study Group

AIMS

To examine the relation between immunisation and the risk of sudden infant death syndrome (SIDS).

METHODS

A large nationwide case-control study. Parental held records were used to measure immunisation status.

RESULTS

Infants were at increased risk of SIDS if they had not received the 6 week, 3 month, and 5 month immunisations. After controlling for potential confounding variables, including those which measured health care use and infant illness, the relative risk of SIDS for infants not being immunised at 6 weeks was 2.1 (95% confidence interval = 1.2, 3.5). Four percent of cases died within four days of immunisation and 7.6% of control infants had been immunised within four days of the nominated date. There was a reduced chance of SIDS in the four days immediately following immunisation (OR = 0.5; 95% CI = 0.2 to 0.9).

CONCLUSIONS

Immunisation does not increase the risk of SIDS and may even lower the risk.

A method for filtering respiratory oscillations

We present a method based on dynamical systems theory which can be used to filter time series in a way which is superior to classical Fourier decomposition. This method is applied to three data-sets, taken from respiratory measurements of two children in quiet and REM sleep. Our purpose is to filter the several different oscillatory mechanisms which operate, in order to provide clearer signals on which further analysis and diagnosis can be based.

Thermal balance and metabolic rate during upper respiratory tract infection in infants

Sequential recordings were made in the first five months after birth of metabolic rate, environmental temperature, and body temperature during sleep at home in 17 infants, each with an older sibling. Further recordings were made whenever an older sibling developed an upper respiratory tract infection (URTI), again four to six days later, and again two weeks later, aiming to achieve recordings before, during, and after an URTI in the infant. The temperature of the room and wrapping of the infant were determined according to their usual practice by the parents. Parents added appropriate wrapping to achieve thermal neutrality based on our calculated values and the measured oxygen consumption. In five of the six infants who developed an URTI in the first three months after birth there was no change or a decrease in metabolic rate at the time of the infection; for infants older than 3 months the metabolic rate increased in three of the five episodes recorded. Peripheral skin temperature decreased at the time of URTI at all ages, though in the older infants it usually increased in parallel with rectal temperature during the latter part of the night, when pyrexia was most common. Infants thus respond to URTI by heat conservation. In the younger infants the lower metabolic rate and the further decrease in this rate with URTI means that fever is rare, and their temperature may decrease on infection. In the older infants the increase in metabolic rate (from an already higher baseline) may result in fever. These differences may contribute to the increased vulnerability of the older infants to heat stress, particularly at the time of acute viral infections.

Preventing marital distress through communication and conflict management training: a 4- and 5-year follow-up

This article reports the 4- and 5-year follow-up results of evaluating the effects of a marital distress prevention program. The program, Prevention and Relationship Enhancement Program (PREP), is a 5-session program designed to teach couples effective communication and conflict management skills. At the 5-year follow-up, intervention, as compared with control, couples had higher levels of positive and lower levels of negative communication skills and lower levels of marital violence. Data are also presented on couples who declined the program. Issues are discussed concerning selection effects, change mechanisms, and future directions for prevention research.