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Biomedical subjects

Peter Johansson

Publications and source records attributed to Peter Johansson.

At least 19 recordsLinked to original sources
PubMed2007

Obstructive sleep apnoea syndrome--patients' perceptions of their sleep and its effects on their life situation.

AIM: This paper reports a descriptive study of how untreated patients with obstructive sleep apnoea syndrome perceived their sleep situation and how the syndrome affected their life situation. BACKGROUND: Obstructive sleep apnoea syndrome is a prevalent problem independently associated with an increased risk for hypertension, cardiovascular disease, chronic heart failure and mortality. Increased consumption of healthcare resources can often be seen among patients over a long period of time since many have been undiagnosed and untreated. METHODS: A phenomenographic approach was employed. Data were collected by interviews during 2005 with 20 purposively selected participants with untreated obstructive sleep apnoea syndrome. Findings. Participants described loud snoring, frequent awakenings, dyspnoea, frustration over nocturia, fear of dying during sleep and partners' anxiety about the apnoea, as being night-time effects of obstructive sleep apnoea syndrome. They described dry and sore throats, tiredness and daytime sleepiness, shame about falling asleep and snoring, thoughts about complications and depressed mood as daytime effects. Needs, such as increased alertness, improved ability to concentrate, improved relationship, adequate information as well as effective treatment, were described. Participants tried self-care strategies such as information-seeking about sleep disturbances and treatment, adapted sleeping routines, change of bedroom arrangements, adapted daily schedules, hyperactivity and avoidance of difficult situations. CONCLUSION: The perceived effects and needs, as well as tried self-care actions by the patients with obstructive sleep apnoea syndrome in this study, could be used to identify and evaluate concerns of other patients with obstructive sleep apnoea syndrome waiting for treatment.

Adult↗
PubMed2006

Sound conditioning protects hearing by activating the hypothalamic-pituitary-adrenal axis.

Sound conditioning primes the auditory system to low levels of acoustic stimuli and reduces damage caused by a subsequent acoustic trauma. This priming activates the HPA axis resulting in the elevation of plasma corticosterone with a consequent upregulation of glucocorticoid receptors (GR) in the cochlea and the paraventricular nucleus (PVN) of the hypothalamus in the mouse. This protective effect is blocked by adrenalectomy or pharmacological treatment with RU486 + metyrapone. Sound conditioning prevents GR down-regulation induced by acoustic trauma and subsequently enhances GR activity in spiral ganglion neurons. Increased SRC-1 expression, triggered by sound conditioning, positively correlates with the upregulation of GR in the cochlea. These findings will help to define the cellular mechanisms responsible for protecting the auditory system from hearing loss by sound conditioning.

Acoustic Stimulation↗
PubMed2006

Glucocorticoid receptors modulate auditory sensitivity to acoustic trauma.

Glucocorticoids are widely used to treat different hearing disorders yet the exact mechanisms of glucocorticoid action on the inner ear are not known. The inner ear of both humans and experimental animals demonstrate an abundance of glucocorticoid receptors (GRs) in both neuronal and non-neuronal tissues. In this review, we discuss how activation of the hypothalamic-pituitary-adrenal axis can directly modulate hearing sensitivity. Recent findings indicate that several factors define the responsiveness of the peripheral auditory system to glucocorticoids including the concentration of agonist, availability of the GR, and the activation of GR and NF-kappaB. These findings will further our understanding of individual glucocorticoid responsiveness to steroid treatment, and will help improve the development of pharmaceuticals to selectively target GR in the inner ear for individuals with increased sensitivity to acoustic trauma.

Animals↗
PubMed2006

Restraint stress modulates glucocorticoid receptors and nuclear factor kappa B in the cochlea.

The regulation of glucocorticoid receptors and nuclear factor kappaB was evaluated in the spiral ganglion neurons after 4 h of restraint stress in the mouse cochlea. Immediately after restraint stress, glucocorticoid receptor protein expression was not altered in spiral ganglion neurons even though both the plasma corticosterone levels and glucocorticoid receptor nuclear translocation increased. By 24 h after restraint stress, the protein expression of glucocorticoid receptors was decreased in spiral ganglion neurons. Pre-treatment with RU486 and metyrapone prevented nuclear translocation of glucocorticoid receptors and nuclear factor kappaB. Moreover, the synthesis of nuclear factor kappaB protein (p65) and inhibitory factor kappaBalpha decreased when RU486 and metyrapone treatment was given before restraint stress. These findings suggest that restraint stress modulates glucocorticoid receptor and nuclear factor kappaB activity in the spiral ganglion neurons, resulting in an altered response to stress.

Analysis of Variance↗
PubMed2006

Improving missing value imputation of microarray data by using spot quality weights.

BACKGROUND: Microarray technology has become popular for gene expression profiling, and many analysis tools have been developed for data interpretation. Most of these tools require complete data, but measurement values are often missing A way to overcome the problem of incomplete data is to impute the missing data before analysis. Many imputation methods have been suggested, some naïve and other more sophisticated taking into account correlation in data. However, these methods are binary in the sense that each spot is considered either missing or present. Hence, they are depending on a cutoff separating poor spots from good spots. We suggest a different approach in which a continuous spot quality weight is built into the imputation methods, allowing for smooth imputations of all spots to larger or lesser degree. RESULTS: We assessed several imputation methods on three data sets containing replicate measurements, and found that weighted methods performed better than non-weighted methods. Of the compared methods, best performance and robustness were achieved with the weighted nearest neighbours method (WeNNI), in which both spot quality and correlations between genes were included in the imputation. CONCLUSION: Including a measure of spot quality improves the accuracy of the missing value imputation. WeNNI, the proposed method is more accurate and less sensitive to parameters than the widely used kNNimpute and LSimpute algorithms.

Algorithms↗
PubMed2006

Glucocorticoid receptor and nuclear factor-kappa B interactions in restraint stress-mediated protection against acoustic trauma.

The role of glucocorticoid receptors (GRs) in the protective effect of restraint stress (RS) before acoustic trauma was studied in spiral ganglion neurons of CBA mice. RS increased corticosterone and protected against elevated auditory brain stem thresholds caused by acoustic trauma. This protection was inhibited by the pretreatment with a corticosterone synthesis inhibitor, metyrapone (MET), and a GR antagonist (RU486). RS followed by acoustic trauma caused an immediate increase in corticosterone that triggered nuclear translocation of GR, without a change in the expression of GR protein. RU486 + MET before RS and acoustic trauma caused an immediate increase in GR mRNA followed by increased GR protein expression (24 h after trauma). GR signaling was further characterized by analyzing nuclear factor-kappaB (NF kappaB) nuclear translocation and protein expression. NF kappaB nuclear translocation was reduced after acoustic trauma or pretreatment with RU486 + MET before RS and acoustic trauma. On the contrary, RS protected against the trauma-induced NF kappaB reduction of its nuclear translocation in inhibitory-kappaB (I kappaB)-dependent manner. RU486 + MET caused a simultaneous decreased I kappaB expression and NF kappaB nuclear translocation, demonstrating an interference with the I kappaB-mediated activation of NF kappaB. In summary, RS protects the cochlea from acoustic trauma by increasing corticosterone and activating GRs. These results emphasis how GR activity modulates hearing sensitivity and its importance for the rationale use of glucocorticoids in inner ear diseases.

Animals↗
PubMed2006

NF-kappaB mediated glucocorticoid response in the inner ear after acoustic trauma.

The inner ear of humans and experimental animals demonstrate an abundance of glucocorticoid receptors (GR). Glucocorticoids (GC) are widely used to treat different hearing disorders; yet the mechanisms of GC action on the inner ear are unknown. We demonstrate how GR can directly modulate hearing sensitivity in response to a moderate acoustic trauma that results in a hearing loss (10-30 dB). The GC agonist (dexamethasone) and the drugs (metyrapone + RU 486) showed opposing effects on hearing threshold shifts. GC agonist (dexamethasone) decreased the hearing threshold whereas pre-treatment with a GC synthesis inhibitor (metyrapone) in combination with a GR antagonist (RU 486) exacerbated auditory threshold shifts (25-60 dB) after acoustic trauma with statistically significant increase in GR mRNA and GR protein compared with the vehicle and acoustic trauma group. Acoustic trauma caused a significant increase in the nuclear transport of NF-kappaB, whereas pre-treatment with the drugs (metyrapone and RU 486) blocked NF-kappaB nuclear transport into spiral ganglion nuclei. An NF-kappaB inhibitor, pyrrolidine dithiocarbamate ammonium blocked the trauma-induced translocation of NF-kappaB and resulted in a hearing loss (45-60) dB. These results indicate that several factors define the responsiveness of the inner ear to GC, including the availability of ligand or receptor, and the nuclear translocation of GR and NF-kappaB. These findings will further our understanding of individual GC responsiveness to steroid treatment, and will help improve the development of pharmaceuticals to selectively target GR in the inner ear for individuals with increased sensitivity to acoustic trauma.

Acoustic Stimulation↗
PubMed2006

Osteopontin is a downstream effector of the PI3-kinase pathway in melanomas that is inversely correlated with functional PTEN.

The tumor suppressor PTEN antagonizes phosphatidylinositol 3-kinase (PI3K), which contributes to tumorigenesis in many cancer types. While PTEN mutations occur in some melanomas, their precise mechanistic consequences have yet to be elucidated. We sought to identify novel downstream effectors of PI3K using a combination of genomic and functional tests. Microarray analysis of 53 melanoma cell lines identified 610 genes differentially expressed (P<0.05) between wild-type lines and those with PTEN aberrations. Many of these genes are known to be involved in the PI3K pathway and other signaling pathways influenced by PTEN. Validation of differential gene expression by qRT-PCR was performed in the original 53 cell lines and an independent set of 18 melanoma lines with known PTEN status. Osteopontin (OPN), a secreted glycophosphoprotein that contributes to tumor progression, was more abundant at both the mRNA and protein level in PTEN mutants. The inverse correlation between OPN and PTEN expression was validated (P<0.02) by immunohistochemistry using melanoma tissue microarrays. Finally, treatment of cell lines with the PI3K inhibitor LY294002 caused a reduction in expression of OPN. These data indicate that OPN acts downstream of PI3K in melanoma and provides insight into how PTEN loss contributes to melanoma development.

Cell Line, Tumor↗
PubMed2006

Detection and identification of protein isoforms using cluster analysis of MALDI-MS mass spectra.

We describe an approach to screen large sets of MALDI-MS mass spectra for protein isoforms separated on two-dimensional electrophoresis gels. Mass spectra are matched against each other by utilizing extracted peak mass lists and hierarchical clustering. The output is presented as dendrograms in which protein isoforms cluster together. Clustering could be applied to mass spectra from different sample sets, dates, and instruments, revealed similarities between mass spectra, and was a useful tool to highlight peptide peaks of interest for further investigation. Shared peak masses in a cluster could be identified and were used to create novel peak mass lists suitable for protein identification using peptide mass fingerprinting. Complex mass spectra consisting of more than one protein were deconvoluted using information from other mass spectra in the same cluster. The number of peptide peaks shared between mass spectra in a cluster was typically found to be larger than the number of peaks that matched to calculated peak masses in databases, thus modified peaks are probably among the shared peptides. Clustering increased the number of peaks associated with a given protein.

Arabidopsis↗
PubMed2006

Epidemiology of the myeloproliferative disorders polycythemia vera and essential thrombocythemia.

The annual incidence of polycythemia vera (PV) and essential thrombocythemia (ET) is approximately 2 and 1.5 per 100,000 inhabitants, respectively, if based on large population surveys and adjusted to a standard population. Survival for ET patients does not differ from that of the general population. However, it appears that PV patients have a significantly higher mortality, at least for patients diagnosed before 1990.

Humans↗
PubMed2006

The measurement and prevalence of depression in patients with chronic heart failure.

Chronic heart failure is a common disease accompanied by poor mental health and depression. The diagnosis of depression is based on the presence of affective, cognitive, and somatic symptoms assessed by categoric or dimensional instruments. Depression is prominent and high rates are found with dimensional instruments in hospitalized heart failure patients. Categoric instruments seem to be more reliable but are more complex to use. Because of poor outcomes, attention should also be paid to subthreshold depression. In screening for such cases, dimensional instruments might be preferable because of the risk for underestimation by categoric instruments. Dimensional instruments might also be easier to implement in daily practice but, to reduce bias, cutoff scores might need refinement according to the clinical setting. Therefore, studies that evaluate different cutoff values are needed to find a critical level of burden from a depressive symptomatology on outcomes such as mortality, hospitalizations, and quality of life.

Chronic Disease↗
PubMed2006

Consequences and predictors of depression in patients with chronic heart failure: implications for nursing care and future research.

Depression is common among patients with chronic heart failure (HF) and leads to more symptoms of HF, decreased quality of life, and an increased risk for premature death. Depressed HF patients also use more health care resources, which increases the economic burden on the health care system. The assessment of risk factors of depression such as age younger than 60-65 years, poor physical functioning, previous depression, poor self-efficacy, living alone, and distressful relationships, in combination with the use of depression instruments, can be helpful in detecting depression in HF patients. Unfortunately, interventions on how to relieve depression in patients with HF have not been investigated thoroughly; however, depression agents as well as HF education, social support, exercise therapy, stress management, and relaxation have been shown to be useful interventions. Because of poor outcomes, studies that examine the effectiveness and/or side effects of pharmacologic as well as nonpharmacologic interventions on depressed patients with HF are needed.

Activities of Daily Living↗
PubMed2005

Factors and interventions influencing health-related quality of life in patients with heart failure: a review of the literature.

INTRODUCTION: Because of the lack of a cure for patients with chronic heart failure (HF), there has been a progressive interest in the use of health-related quality of life (Hr-QoL) as complementary end-point to mortality and morbidity. AIM: The aim of this review was from a nursing perspective to describe Hr-QoL and the influencing factors of Hr-QoL, as well as to identify interventions aimed at influencing Hr-QoL in HF patients. METHOD: Medline, Cinahl and PsycInfo databases were searched from 1995 to 2004. A total of 58 papers were included. RESULTS: HF symptoms and activity status influence Hr-QoL negatively. However, several individual characteristics such as personality, gender and age must also be taken into consideration because different values might exist regarding what constitutes a good Hr-QoL. Nurse led interventions based on education, support and exercise can influence Hr-QoL positively. There is also a need of more studies about the effects of depression, sleep disturbances, support as well as education on Hr-QoL. There is also a need of exercise studies with larger sample sizes and older patients in higher NYHA classes. CONCLUSION: Several individual factors impact Hr-QoL, therefore, must nursing interventions are individually adapted to the patient's resources.

Activities of Daily Living↗
PubMed2005

Sleep disturbances in patients with chronic heart failure and their holistic consequences-what different care actions can be implemented?

BACKGROUND: Sleep disturbances are prevalent among elderly, especially among those with chronic heart failure (CHF) and can affect all dimensions of quality of life (QOL) negatively. AIM: To describe the most common causes leading to sleep disturbances in patients with CHF, their consequences from a holistic perspective and different care actions that can be implemented. METHODS: MEDLINE and CINAHL databases were searched from 1989 to July 2004. FINDINGS: Sleep disordered breathing (SDB), and insomnia were the most common causes for sleep disturbances and occurs in 45--82% (SDB) and one-third (insomnia) of all patients with CHF. SDB cause a disturbed sleep structure with frequent awakenings, as well as several adverse effects on the cardiovascular system causing increased morbidity and mortality. Insomnia, caused by anxiety, an unknown life situation in relation to the debut of CHF, or symptoms/deteriorations of CHF can lead to negative effects on all aspects of QOL, as well as daytime sleepiness. CONCLUSION: The high prevalence of sleep disturbances and their holistic consequences should be taken into account when nurses asses and plan the care for patients with CHF. Randomized studies with large sample sizes evaluating non-pharmacological nursing interventions that improve sleep are needed.

Aged↗
PubMed2005

Nurses' assessments and patients' perceptions: development of the Night Nursing Care Instrument (NNCI), measuring nursing care at night.

BACKGROUND: Nursing care provided at night has a different purpose and objective to that provided during the day. A review of the literature does not reveal any scientifically tested research instruments for evaluating and comparing the nurse's assessment of nursing care with the patient's perception at night. AIMS AND OBJECTIVES: The aim of this study was to develop and test an instrument for evaluating nursing care and to compare nurses' assessments with patients' perceptions of nursing care provided at night. DESIGN: The study was carried out in two phases; the first had an explorative design and the second an evaluative and comparative design. The Night Nursing Care Instrument (NNCI) included two questionnaires; one for nurses and one for patients. These questionnaires were developed from a nursing framework and covered the following three areas: 'nursing interventions', 'medical interventions' and 'evaluation'. METHODS: Nurses (n = 40) on night duty on a medical ward at a central hospital in southern Sweden were consecutively selected, to participate in the study. The patients (n = 80) were selected by means of convenience sampling. In order to achieve construct validity, factor analysis of each individual area was carried out. Reliability in terms of internal consistency was tested by Cronbach's alpha. RESULTS: The overall NNCI had acceptable reliability and validity. There was no statistically significant difference between nurses' assessments and patients' perceptions in any of the three areas of 'nursing interventions', 'medical interventions' or 'evaluation'. The patients rated night nursing care as satisfactory for the majority of the items. RELEVANCE TO CLINICAL PRACTICE: These findings demonstrate that it is possible to create a short instrument with acceptable reliability and validity, which is easy to use in clinical practice. The results also show that night nurses need to improve their ability to assess patients' needs during the night to increase the quality of night nursing care.

Adult↗
PubMed2005

Linking adult psychopathy with childhood hyperactivity-impulsivity-attention problems and conduct problems through retrospective self-reports.

The purpose of the present study was to test whether adult criminals with psychopathy diagnoses, more than those without, have histories of hyperactivity-impulsivity-attention problems (HIA) and conduct problems (CP). We compared psychopathic and nonpsychopathic violent criminal offenders on retrospective reports of conduct problems before the age of 15 and hyperactivity-impulsivity-attention problems before the age of 10. We used a sample of 186 adult men sentenced to prison in Sweden for 4 years or more for violent, nonsexual crimes. The mean age was 30.7( SD = 9.4). The results showed that a combination of childhood HIA problems and CP was typical for adult psychopathic offenders. They were four times more likely than chance to have had a combination of HIA problems and CP during childhood and only one-fifth as likely than chance to have had neither problem. Nonpsychopathic offenders, on the other hand, were five times more likely than chance to have had neither problem and only one-quarter as likely than chance to have had both problems.

Adolescent↗
PubMed2005

Psychopathy and intelligence: a second look.

Empirical studies using the PCL-R (Hare, 2003) have shown no intelligence differences between psychopaths and nonpsychopaths. However, Cleckley (1976) argued that psychopaths often show superior intelligence. The purpose of the present study was to test the hypothesis that the correlation between intelligence and severity of criminal development is the opposite in psychopaths than in nonpsychopathic criminals using a sample of 370 men sentenced for violent (nonsexual) crimes. That pattern would provide a way of explaining the discrepancy between Cleckley's view and later empirical work. The results showed that for nonpsychopaths, higher total IQ and particularly verbal intelligence meant a later start in violent crime. For those diagnosed as psychopaths, however, this association was reversed.

Adult↗