Nina Hautala

GATA-4 is a nuclear mediator of mechanical stretch-activated hypertrophic program

In overloaded heart the cardiomyocytes adapt to increased mechanical and neurohumoral stress by activation of hypertrophic program, resulting in morphological changes of individual cells and specific changes in gene expression. Accumulating evidence suggests an important role for the zinc finger transcription factor GATA-4 in hypertrophic agonist-induced cardiac hypertrophy. However, its role in stretch-induced cardiomyocyte hypertrophy is not known. We employed an in vitro mechanical stretch model of cultured cardiomyocytes and used rat B-type natriuretic peptide promoter as stretch-sensitive reporter gene. Stretch transiently increased GATA-4 DNA binding activity and transcript levels, which was followed by increases in the expression of B-type natriuretic peptide as well as atrial natriuretic peptide and skeletal α-actin genes. The stretch inducibility mapped primarily to the proximal 520 bp of the B-type natriuretic peptide promoter. Mutational studies showed that the tandem GATA consensus sites of the proximal promoter in combination with an Nkx-2.5 binding element are critical for stretch-activated B-type natriuretic peptide transcription. Inhibition of GATA-4 protein production by adenovirus-mediated transfer of GATA-4 antisense cDNA blocked stretch-induced increases in B-type natriuretic peptide transcript levels and the sarcomere reorganization. The proportion of myocytes with assembled sarcomeres in control adenovirus-infected cultures increased from 14 to 59% in response to stretch, whereas the values for GATA-4 antisense-treated cells were 6 and 13%, respectively. These results show that activation of GATA-4, in cooperation with a factor binding on Nkx-2.5 binding element, is essential for mechanical stretch-induced cardiomyocyte hypertrophy.

Pressure Overload Increases GATA4 Binding Activity via Endothelin-1

Background —The signaling cascades responsible for the activation of transcription factors in the hypertrophic growth of cardiac myocytes during hemodynamic overload are largely unknown. Several of the genes upregulated in the hypertrophied heart, including B-type natriuretic peptide (BNP) gene, are controlled by the cardiac-restricted zinc finger transcription factor GATA4. Methods and Results —An in vivo model of intravenous administration of arginine8-vasopressin (AVP) for up to 4 hours in conscious normotensive rats was used to study the signaling mechanisms for GATA activation in response to pressure overload. Gel mobility shift assays were used to analyze the trans-acting factors that interact with the GATA motifs of the BNP promoter. AVP-induced increase in mean arterial pressure was followed by a significant increase in the BNP and c-fos mRNA levels in both the endocardial and epicardial layers of the left ventricle, whereas GATA4 and GATA6 mRNA levels remained unchanged. Pressure overload within 15 to 60 minutes produced an increase in left ventricular BNP GATA4 but not GATA5 and GATA6 binding activity, and at 30 minutes a 2.2-fold increase (P <0.001) in GATA4 binding was noted. The mixed endothelin-1 ETA/ETB receptor antagonist bosentan but not the angiotensin II type 1 receptor antagonist losartan completely inhibited the pressure overload–induced increase in left ventricular BNP GATA4 binding activity. Bosentan alone had no statistically significant effect on GATA4 binding activity of the left ventricle in conscious animals. Conclusions —ET-1 is a signaling molecule that rapidly upregulates GATA4 DNA binding activity in response to pressure overload in vivo.

Central nervous system-related symptoms and findings are common in acute Puumala hantavirus infection.

Abstract Background. Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome (HFRS) also called nephropathia epidemica (NE). Recent case reports and retrospective studies suggest that NE may damage the pituitary gland. Based on these observations, our goal was to explore the nature of this complication prospectively. Methods. A total of 58 hospitalized patients with acute NE volunteered to participate. Central nervous system (CNS) symptoms were recorded, cerebrospinal fluid (CSF) samples were collected, human leukocyte antigen (HLA) haplotype was analyzed, brain magnetic resonance imaging (MRI) was acquired, and electroencephalography (EEG) was recorded. Patients with abnormal pituitary MRI finding were examined by an endocrinologist. Results. Most patients experienced CNS symptoms, and half of the CSF samples were positive for PUUV IgM, elevated protein level, or leukocyte count. CSF of patients negative for DR15(2)-DQ6 haplotype was less frequently affected. MRI revealed pituitary hemorrhage in two patients; these two patients suffered sudden loss of vision associated with headache, and they both developed hypopituitarism. Only one patient required long-term hormonal replacement therapy. Conclusion. CNS-related symptoms and inflammation in the CSF are common in acute NE. Genetic properties of the host may predispose to CNS involvement. It does seem that pituitary injury and subsequent hormonal insufficiency may complicate the recovery.

Marked reductions in visual impairment due to diabetic retinopathy achieved by efficient screening and timely treatment

Diabetic retinopathy (DR) is the most common complication of diabetes and needs to be diagnosed early to prevent severe sight‐threatening retinopathy. Digital photography with telemedicine connections is a novel way to deliver cost‐effective, accessible screening to remote areas. Screening for DR in a mobile eye examination unit (EyeMo) is compared to traditional service models (i.e. local municipal services or a commercial service provider). The quality of images, delays from screening to treatment, the stage of DR, coverage of screening and the rate of visual impairment due to DR are evaluated.

Cardiac BNP gene activation by angiotensin II in vivo

The transcription factors involved in the activation of cardiac gene expression by angiotensin II (Ang II) in vivo are not well understood. Here we studied the contribution of transcriptional elements to the activation of the cardiac B-type natriuretic peptide (BNP) gene promoter by Ang II in conscious rats and in angiotensin II type 1 receptor (AT1R) transgenic mice. Rat BNP luciferase reporter gene constructs were injected into the left ventricular wall. The mean luciferase activity was 1.8-fold higher (P<0.05) in the ventricles of animals subjected to 2-week Ang II infusion as compared with vehicle infusion. Our results indicate that GATA binding sites at -90 and -81 in the rat BNP promoter are essential for the in vivo response to Ang II. The GATA factor binding to these sites is GATA-4. BNP mRNA levels and GATA-4 binding activity are also increased in the hypertrophied hearts of aged AT1R transgenic mice.

Prospective study on ocular findings in acute Puumala hantavirus infection in hospitalised patients

Aims To appraise the ocular manifestations of Puumala hantavirus evoked haemorrhagic fever with renal syndrome nephropathia epidemica (NE) and to clarify the mechanisms of ocular changes in the largest series of patients examined to date. Methods 92 eyes of 46 patients with serologically proven NE were examined during the acute phase and after clinical recovery. Ocular symptoms were recorded, and visual acuity, refraction, intraocular pressure and ocular dimensions were evaluated. Results 88% of the patients experienced decreased intraocular pressure (IOP) (p<0.001), 87% reduced visual acuity, 87% conjunctival chemosis, 82% thickening of the lens (p<0.05), 78% myopic shift (p<0.001), 64% shallowing of the anterior chamber (p<0.05) and 52% shallowing of vitreous length (p<0.05) during the acute phase compared with that measured after clinical recovery. In all, 70% of the patients reported ocular symptoms. Conclusion Ocular symptoms and disturbances are common in acute NE, and the symmetry of the ocular changes reflects the systemic nature of the disease. A decrease in IOP and myopic shift mainly due to thickening of the lens are evident in acute disease. The myopic shift only partially explains the visual disturbances supporting the possible multifactorial origin of the ocular findings in patients with NE.

A mobile eye unit for screening of diabetic retinopathy and follow‐up of glaucoma in remote locations in northern Finland

Editor, I n industrialized countries, the rate of type 2 diabetes mellitus is increasing in an exponential manner. The proper screening of diabetic retinopathy in rapidly increasing patient populations poses major challenges to health care systems. In Finland, the yearly 3% increase in the number of patients receiving glaucoma therapy further burdens the eye health care system (Tuulonen et al. 2009). The Northern Ostrobothnia Hospital District is responsible for the provision of specialized health care services for its population of 382 000. The distances between facilities and patients within this sparsely inhabited hospital district can be > 200 km. In this area, there are over 13 000 diabetes patients and 4400 patients who receive medication for glaucoma (Finnish Social Insurance Institution, 2008). In order to improve the screening of diabetic retinopathy and the follow-up of glaucoma, we developed an alternative way of delivering services by constructing a mobile examination unit, called ‘EyeMo’ (Fig. 1). The Ministry of Health and Social Welfare in Finland supported the financing of the unit. The goal was to produce a way of providing high-volume services (such as high-quality fundus images and visual field examinations) at low unit costs and to guarantee equal access to care. EyeMo is 10.5 m long and 2.5 m wide. It has two examination rooms, one for visual field testing (Humphrey Field Analyzer HFA-740i; Carl Zeiss Meditec, Inc., Dublin, CA, USA) and one for imaging (using a Canon CF-1 mydriatic fundus camera with a Canon 400 digital SLR camera), as well as a waiting area. Two experienced professionals, a nurse and an imaging technician, work in the unit. Since September 2006, over 7000 patients have been seen and about 7700 examinations conducted in EyeMo. In glaucoma patients, the imaging technician takes one wide-angle image per eye from which both the optic nerve head and retinal nerve fibre layer can be evaluated. In diabetes patients, two images are taken, one centred on the optic disc and the other on the macula. The imaging technician records the images, transfers them to the server and forwards the proposed screening schedules to the municipal health authorities. Standard medical equipment, plain technology and teleradiology practices are used in the mobile unit. DICOM (Digital Imaging and Communications in Medicine) standards are used for data transfer of imaging and visual fields. Confidentiality and security are ensured and the data protection guidelines of the hospital are followed. Feedback to the municipal health authorities is transferred electronically. For diabetes patients, the images are pre-screened in the unit by a nurse who has been specially trained for this task. If no diabetic retinopathy is detected, the nurse makes a recommendation for the next screening according to the national clinical practice guideline. If the imaging results are abnormal, the images are forwarded to an ophthalmologist for off-line consultation (about 30% of images). The purpose of this is to ensure that the images are analysed and feedback provided to the municipal health authorities without delay in order to ensure rapid provision of care. The glaucoma patients seen in EyeMo comprise stable glaucoma patients whose follow-up has been judged to be suitable for monitoring by the mobile unit. In EyeMo, the nurse measures the intraocular pressure and compares it with the pre-set target pressure. Visual fields and fundus images are monitored according to the protocol defined in the national clinical practice guidelines (Tuulonen et al. 2003). The glaucoma test results are analysed off-line by a glaucoma specialist. If necessary, online services are available by telephone and the system can be integrated into the hospital’s electronic patient record database through the third generation of telecommunication hardware standards generally used for mobile networking (3G). After two complete operational years, the unit has received glowing feedback, not only from patients, but also from the authorities which bear the costs of the unit (the municipalities). The benefits of the service to patients include faster access to care, regional equality, a reduced need to Fig. 1. The mobile examination unit, designated EyeMo, is equipped with a waiting area and examination rooms for fundus imaging, visual field testing and measurement of intraocular pressure. Acta Ophthalmologica 2009

Prevalence of retinopathy in Finnish children and adolescents with type 1 diabetes: a cross-sectional population-based retrospective study

Aim A population-based study was carried out to evaluate the prevalence and risk factors of diabetic retinopathy (DR) in children with type 1 diabetes (T1D) in The Northern Osthrobothnia Hospital District, Finland. The aim was to compare the current prevalence and the risk factors with those obtained in a study performed in a similar setting 17 years earlier. Methods and patients The prevalence of DR was evaluated from fundus photographs in a cross-sectional manner in children and adolescents with T1D (n=297) living in the Northern Osthrobothnia Hospital District on 1 January 2007. Results The prevalence of DR was 7.6% (12/158) in males and 16.5% (23/139) in females in the present study and 7.3% in males and 12.9% in females in the former study. The mean age of the patients was 11.9 and 11.8 years, and the mean duration of diabetes was 4.9 and 5.0 years in the present and the former study, respectively. DR was associated with older age (p<0.001), longer duration of diabetes (p<0.001), higher glycated haemoglobin A1c (GHbA1c) (9.3% in those with DR vs 8.3% in those without DR, p=0.001, or 78 vs 67 mmol/mol, respectively) and female sex (p=0.016); in a logistic regression analysis, these factors explained 35% of DR. These risk factors are essentially the same as identified in the cohort 17 years earlier. GHbA1c levels had not significantly improved during that time. Conclusions The overall prevalence of DR among children with T1D was 11.8% (35/297) showing no decrease over the past 17 years; in girls, DR was diagnosed more often in the present than in the former study, but there was no change in the prevalence among the boys. Glycaemic control had remained unchanged.

Young male patients are at elevated risk of developing serious central nervous system complications during acute Puumala hantavirus infection

BackgroundOur aim was to characterize clinical properties and laboratory parameters in patients with or without cerebrospinal fluid (CSF) findings suggestive of central nervous system (CNS) involvement, and especially those who developed serious CNS complications during acute nephropathia epidemica (NE) caused by Puumala hantavirus (PUUV) infection.MethodsA prospective cohort of 40 patients with acute NE and no signs of major CNS complications was analyzed. In addition, 8 patients with major CNS complications associated with NE were characterized. We collected data of CNS symptoms, CSF analysis, brain magnetic resonance imaging (MRI) results, electroencephalography (EEG) recordings, kidney function, and a number of laboratory parameters. Selected patients were evaluated by an ophthalmologist.ResultsPatients with a positive CSF PUUV IgM finding or major CNS complications were more often males (p < 0.05) and they had higher plasma creatinine values (p < 0.001) compared to those with negative CSF PUUV IgM. The degree of tissue edema did not explain the CSF findings. Patients with major CNS complications were younger than those with negative CSF PUUV IgM finding (52.9 vs. 38.5 years, p < 0.05). Some patients developed permanent neurological and ophthalmological impairments.ConclusionsCNS and ocular involvement during and after acute NE can cause permanent damage and these symptoms seem to be attributable to true infection of the CNS rather than increased tissue permeability. The possibility of this condition should be borne in mind especially in young male patients.

Major Age Group-Specific Differences in Conjunctival Bacteria and Evolution of Antimicrobial Resistance Revealed by Laboratory Data Surveillance

Purpose: We hypothesized that observation and analysis of microbiological laboratory statistics from patients with suspected bacterial conjunctivitis should increase our understanding of microbiological epidemiology of the disease in age categories. We further assumed that the statistical data should expose evolution of antimicrobial resistance that may eventually have an influence on clinical decisions. Materials and Methods: We analyzed statistical data of bacterial isolates (1139 strains) and their resistance to common antibiotics from 2494 patients with suspected bacterial conjunctivitis. Results: Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus displayed their presence in 0- to 5-year-old children. Staphylococcus aureus and Pseudomonas aeruginosa were the most common in the elderly (>age 70) among whom a rapid increase in resistance of Staphylococcus aureus to methicillin (MRSA) was recognized. Conclusions: Our study demonstrates that the spectrum of conjunctival bacteria varies among age groups. In addition, our results confirm that a shift in antimicrobial susceptibility can be rapid and age-group specific, thus emphasizing the need for continuous surveillance of bacterial findings.