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- Chotai, Jayanti, 1948-
(författare)
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Season of birth in suicidology : neurobiological and epidemiological studies
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Several neuropsychiatrie disorders have shown season of birth associations. Low cerebrospinal fluid (CSF) levels of the serotonin metabolite 5-HIAA and the dopamine metabolite HVA have been associated with suicidal behaviour, impulsivity, and aggression. This thesis investigated associations between the season of birth, the CSF levels of three monoamine metabolites (including MHPG of norepinephrine), the scales of the diagnostic interview for borderline patients (DIB), and psychiatric diagnoses. Also, the methods of suicide were investigated in relation to the season of birth.Methods: We studied a clinical sample of 241 patients in Stockholm with mood, anxiety and adjustment disorders with respect to the CSF levels of monoamine metabolites in relation to the season of birth, and in relation to the DIB in an overlapping sample. We also analysed all completed suicides during the 42 years 1952- 1993inVästerbottenin northern Sweden (1466 cases) by multiple logistic regressions to relate suicide methods with season of birth, gender, age, urban-rural residence, marital status, year of suicide, and season of suicide. For the 20 years 1961- 1980 (693cases), psychiatric in-patient and out-patient records were also examined for any history of psychiatric contacts and psychiatric diagnoses. In two mutually independent samples, we investigated the DIB in relation to the season of birth.Results: In the Stockholm sample, those born during February to April had significantly lower CSF levels of 5-HIAA, and those born during October to January had significantly higher CSF levels of HVA, HVA/5-HIAA, and HVA/MHPG, as well as (non-significantly) higher levels of 5-HIAA. Those with an intermediate score of section II (impulse action patterns) of the DIB had significantly higher CSF levels of 5-HIAA and HVA, and they were significantly more likely to have been born during October to January. In the Västerbotten register, those born during February to April were significantly more likely to have preferred hanging rather than poisoning or petrol gases, and conversely for those born during October to January. These associations with suicide methods were found for the total sample and for those without any history of psychiatric contacts, but not for those with psychiatric contacts.Conclusions: Suicidal behaviour shows statistically significant variation according to the season of birth, most probably mediated by a variation in an independent trait of vulnerability to suicide based on neurodevelopmental parameters, particularly the serotonergic system. The suicidal process differs between those who seek psychiatric care compared to those who do not, reflecting differences in the diagnostic spectra and in the extent of mental illness.
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- Olofsson, Katarina
(författare)
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Immune cells in human pharyngeal and palatine tonsils and in the uvula : tissue distribution, cellular composition and functional properties
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The adenoid (pharyngeal tonsil), the palatine tonsils and the uvula are strategically located at the entrance of the upper airodigestive tract. By virtue of their location they are incessantly exposed to inhaled and ingested antigens. Severe nasal obstruction, otitis media with effusion, recurrent tinsillitis and obstructive airways during sleep are conditions often due to diseases in these organs.To advance our knowledge about the etiology and pathogenesis of these diseases, we have compared immune cell composition, cytokine expression and microbial colonisation in adenoids from children with hypertrophic obstructive adenoid (HOA) and chronically infected adenoid (CIA). Similarly, we compared immune cell composition in palatine tonsils from children with idiopathic tonsillar hypertrophy and recurrent tonsillitis. Finally, we wanted to characterise the human uvula from an immunological point of view, which had previously not been done. Its composition and distribution of immune cells, its cytokine profile, connective tissue elements and ultrastructure was studied.When comparing adenoids from children with HOA and CIA, the most striking finding was their similarity. A cytokine profile that was independent of diagnosis but seemed characteristic for the adenoid emerged. T cell expression of IL-5 and TGF-β1 but not IL-4 suggested an ongoing humoral response driven by a "mucosal TH2" cell. αβ T cells also expressed TNF-α, IFN-γ and IL-2, indicating a concomitant cell mediated response. Cell mediated immune responses often reflect viral infection. In line with this, adenovirus DNA was found in 80% of the adenoid samples. Furthermore, IL-6, IL-8 and TNF-α expressed in the non-T cell fraction suggested that the tissue macrophages were activated. TNF-α, IFN-γ and TGF-β1 were expressed by γδ T cells. The following differences between HOA and CIA were however, noted: i) most intraepithelial lymphocytes were CD8+ γδ T cells in HOA, while CD8+ αβ T cells dominated intraepithelially in CIA; ii) the number of follicles was twice as high in CIA as in HOA; iii) there were signifacantly more granulocytes in the interfollicular area in CIA than in HOA; iv)IL-6 mRNA expressing γδ T cells were only found in HOA and v) there was a tendency of higher TNF-α mRNA levels in non-T cells of CIA compared to HOA. The following scenarios emerge: in CIA there appears to be an inadequate first line of defence, with a low frequency of intraepithelial γδ T cells and a high frequency of cytotoxic CD8+ αβ T cells eliminating infected epithelial cells. Togehter, these two conditions cause a "leaky" epithelium, allowing infiltration of microbes into the underlying tissue and subsequent recruitment of granulocytes and follicle formation initiated by activated macrophages. In HOA, activated intraepithelial γδ T cells appear to be involved in antimicrobial defence reactions and surveillance of the epithelium.The difference in leukocyte profiles between tonsils from patients subjected to surgery due to idiopathic tonsillar hypertrophy or recurrent tonsillitis was limited to the surface epithelium. CD8+ γδ T cells utilising the unusual combination Vδ1/Vγ9 in their T cell receptor constituted the majority of intraepithelial lymphocytes in both groups. However, the frequency of these cells was significantly higher in recurrent tonsillitis. These results suggest that CD8+ Vδ1/Vγ9+ γδ T cells are characteristic of palatine tonsils and selectively expanded in recurrent tonsillitis. These γδ T cells may be involved in clearing infectious bacteria at the surface of the tonsil.Tissue macrophages, αβ T cells, γδ T cells, mast cells and B cells constituted, in declining order, the immune cell populations in the uvula. No fillicle-like structures were present. Most T cells had a CD8+ CD28-TCR-αβ+ phenotype, suggesting a down-regulatory function. Production of the down-regulatory cytokine TGF-β was also noted. This is consistent with the hypothesis that the uvula contributes to the development of mucosal tolerance. Furthermore, the uvula seems to be protected from pathogens penetrating the internal milieu by a subepithelial barrier of γδ T cells and macrophages. TNF-α secreting immune cells were found at this location. TNF-α and TGF-β may cause tissue fibrosis, TNF-α indirectly by stimulating mast cells to release histamine. Tissue fibrosis in conjunction with water binding to hyaluronan present in the connective tissue is the most likely explanation for the observed enlargement of the uvula in patients with sleeping disorders.
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