Mycobacterium avium infections in children

Mycobacterium avium belongs to a group of over 130 species of non-tuberculous mycobacteria (NTM) or environmental mycobacteria. The subspecies Mycobacterium avium avium was originally described as the causative agent of bird tuberculosis, but was later found to cause disease also in humans. Small children display a special form of infection that is seldom detected in other age groups. It manifests as a chronic lymphadenitis usually in the head and neck region. The incidence rate is approximately 1-5/100,000 children/year. However, exposure to this bacterium is high as judged by sensitin skin test studies. Even if a lot of persons are infected with M. avium, a majority of them do not develop disease and the bacterium is therefore considered to be of low virulence, causing disease mainly in immunocompromised persons. Children with M. avium lymphadenitis, however, usually do not have any known deficiencies in the immune system. This thesis elucidates why small children are prone to develop disease by M. avium. Investigation of a possible zoonotic spread of this bacterium to children involved analysis and comparison of different strains isolated from birds and other animals and from children, using the restriction fragment length polymorphism (RFLP) method on insertion sequence IS1245, resulting in the finding that the children were infected exclusively with the new proposed subspecies M. avium hominissuis. Animals in general and birds in particular were infected with the subspecies M. avium avium (using the more narrow definition). Moreover, when investigating the immunological response of human peripheral blood mononuclear cells (PBMCs) to stimulation with M. avium hominissuis and M. avium avium, respectively, it was found that the former subspecies induced lower IFN-γ and IL-17 than the latter, but higher levels of Il-10, which might contribute to explain the higher pathogenicity of M. avium hominissuis in humans. Through studies of the geographical distribution of cases of M. avium infection in children in Sweden and the seasonal variation of the disease, a fluctuation of the incidence over the year was detected, with higher numbers of cases in the autumn months and lower numbers in the late spring. There was a higher incidence rate in children living close to water than in those living in the inland or in the urban areas. Therefore, outdoor natural water is the most probable source of infection in children with M. avium lymphadenitis. Through a descriptive clinical retrospective study, complete surgical removal of the affected lymph node was found to lead to better results than treatment by incision and drainage of abscess or expectation only. Finally there might be several explanations as to why an individual develops disease after infection with M. avium, such as, exposure, bacterial virulence factors or possible specific deficiencies of the immune system of the host or a combination of these factors. Which are the more important factors regarding children with M. avium lymphadenitis is still an open question

Blyga barn : En intervjustudie om hur man upplever sig jobba med blyga barn på förskolan

Denna studie handlar om egenskapen blyghet hos barn. Inom svensk forskning är detta något som knappt uppmärksammas medan det i internationell forskning är något som studerats länge. Man pratar om det som en personlig egenskap som man, vid stora problem, kan få hjälp med att hantera, men också som ett problem som lärare ser och försöker arbeta aktivt med. Som det framgår ovan var syftet med den här studien att undersöka hur svenska förskollärare jobbar med att upptäcka och aktivt stärka blyga barn i deras utveckling. Avsaknaden av svensk forskning om egenskapen blyghet är samtidigt något som uppmärksammas och diskuteras.  För att studera uppfattningar om egenskapen blyghet gjordes intervjuer med treförskollärare. Även om urvalet är litet visade resultatet på att förskollärarna inte ville kalla barnen blyga utan istället valde att kalla det för att de var försiktiga. Trots att de inte ville använda sig av begreppet blyghet menade sig de intervjuade förskollärarna att de aktivt jobbade mycket för att ge barnen stöd i barngruppen så att de så småningom vågade ta mer plats och bli mindre blyga. Även om materialet är så pass litet att det inte går att ge någon generell bild av hur man ser på egenskapen blyghet i svenska förskolor, kan resultatet peka på att avsaknaden av svensk forskning inom området påverkar hur svenska förskollärare ser på blyghet som något annat än att vara blyg. Detta diskuteras mot den starka forskningstradition som finns i bl.a. USA när det gäller att studera blyghet och dess konsekvenser men också hur man kan jobba med att stärka barnet för att bli mindre blygt. Ett intressant resultat som kommer fram i studien är hur de svenska förskollärarna visar en viss rädsla över att aktivt jobba för att motverka blyghet hos barn då det skulle kunna påverka barnets personlighet på ett negativt sätt

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Lower left atrial function in young individuals with type 1 diabetes mellitus compared to healthy controls: an echocardiographic study

Abstract In adulthood, individuals with type 1 diabetes mellitus may develop a condition of heart failure with preserved ejection fraction. However, subclinical changes to the heart in diabetes are likely to occur prior to the clinical presentation. This cross-sectional study aimed to compare left atrial function by echocardiography between 43 individuals with type 1 diabetes and 43 healthy controls, aged 10–30 years. All participants underwent echocardiography and 2D speckle tracking measurements for left atrial phase function parameters. Physical capacity was assessed by exercise test on a bicycle. Results showed that participants with type 1 diabetes had significantly lower left atrial function parameters than healthy controls (p < 0.05). There was a significant negative correlation between HbA1c means and reservoir and conduit strain (p < 0.05) and individuals with BMI < 30 showed a lower left atrial stiffness (p < 0.05). Individuals with type 1 diabetes and a higher physical capacity did not differ from their healthy peers. Results indicate that lower HbA1c levels, BMI < 30 and a higher physical capacity are favourable in terms of left atrial function in children and young adults with type 1 diabetes mellitus. Left atrial strain by echocardiography might become a new important tool in assessing heart function in T1DM

hominissuis Give Different Cytokine Responses after in

Mycobacterium avium avium and Mycobacterium avium hominissuis give different cytokine responses after in vitro stimulation of human blood mononuclear cell

Assessing heart rate variability in type 1 diabetes mellitus—Psychosocial stress a possible confounder

Abstract Background Autonomic neuropathy (AN) commonly arises as a long‐term complication in diabetes mellitus and can be diagnosed from heart rate variability (HRV), calculated from electrocardiogram recordings. Psychosocial stress also affects HRV and could be one of several confounders for cardiac AN. The present work investigated the impact of psychosocial stress on HRV in individuals with type 1 diabetes mellitus (T1DM) and assessed the use of salivary cortisol as a biomarker for psychosocial stress in this context. Methods A total of 167 individuals 6–60 years old (113 with T1DM and 54 healthy controls) underwent 24‐hr ECG recordings with HRV analysis. Salivary cortisol was sampled thrice during the registration day. Perceived psychosocial stress along with other factors of possible importance for the interpretation of HRV was documented in a diary. Results Heart rate variability (high‐frequency power during sleep) was reduced (p < .05) with older age, longer diabetes duration, higher mean glucose levels, physical inactivity, and perceived psychosocial stress. Salivary cortisol levels in the evening were increased (p < .05) in women in ovulation phase, in individuals with preceding hypoglycemia or with hyperglycemia. The amplitude of salivary cortisol was reduced (p < .05) with the presence of perceived psychosocial stress, but only in adult healthy controls, not in individuals with diabetes. Conclusion Psychosocial stress might be a confounder for reduced HRV when diagnosing cardiac AN in T1DM. Salivary cortisol is, however, not a useful biomarker for psychosocial stress in diabetes since the physiological stress of both hypoglycemia and hyperglycemia seems to overrule the effect of psychosocial stress on cortisol

Mycobacterium avium Lymphadenopathy among Children, Sweden

We studied Mycobacterium avium lymphadenopathy in 183 Swedish children (<7 years of age) from 1998 through 2003. Seasonal variation in the frequency of the disease, with a peak in October and a low point in April, suggests cyclic environmental factors. We also found a higher incidence of the disease in children who live close to water

Mycobacterium avium Subsp. avium and Subsp. hominissuis Give Different Cytokine Responses after in vitro Stimulation of Human Blood Mononuclear Cells

BACKGROUND: Mycobacterium avium is the principal etiologic agent of non-tuberculous lymphadenitis in children. It is also a known pathogen for birds and other animals. Genetic typing of M. avium isolates has led to a proposal to expand the set of subspecies to include M. avium subsp. hominissuis. Isolates associated with disease in humans belong to this subspecies. METHODOLOGY/PRINCIPAL FINDINGS: Peripheral blood mononuclear cells from six healthy blood donors were stimulated in vitro with ten isolates of M. avium avium and 11 isolates of M. avium hominissuis followed by multiplex bead array quantification of cytokines in supernatants. M. avium hominissuis isolates induced significantly more IL-10 and significantly less IL-12p70, TNF, IFN-γ and IL-17 when compared to M. avium avium isolates. All strains induced high levels of IL-17, but had very low levels of IL-12p70. CONCLUSION/SIGNIFICANCE: The strong association between M. avium subsp. hominissuis and disease in humans and the clear differences in the human immune response to M. avium subsp. hominissuis compared to M. avium subsp. avium isolates, as demonstrated in this study, suggest that genetic differences between M. avium isolates play an important role in the pathogenicity in humans

Geometric means of cytokine levels: (A) IL-10, (B) IL-12p70, (C) TNF, (D) IFN-γ, (E) IL-17.

<p>Cytokine levels in pg/mL after stimulation with 5×10⁷ inactivated bacteria/mL of PBMCs from six healthy blood donors are shown. IL-10, IL-12p70 and TNF were measured after a 24 h stimulation; IFN-γ and IL-17 after five days of stimulation. Geometric means and 95% confidence intervals are shown. F) <b>Arithmetic means of cytokine levels.</b> The arithmetic mean of the cytokine level (pg/mL) for each individual isolate is shown. M avium a = <i>Mycobacterium avium avium</i>; M avium h = <i>Mycobacterium avium homunissuis</i>; No Bact = no bacteria; G+ = <i>Streptococcus mitis</i>; G− = <i>Escherichia coli</i>. Note that Figure F is shown on a logarithmic scale.</p

<i>Mycobacterium avium</i> strains included in this study.

<p><i>Mycobacterium avium</i> strains included in this study.</p