Bacterial toxins associated with cot death
Başlık:
Bacterial toxins associated with cot death
Yazar:
Sayers, Nicola MacDonald, author.
ISBN:
9780438043244
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (453 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
Sudden Infant Death Syndrome (SIDS) is the leading cause of post neonatal death in the developed world. The role of bacterial toxins in the pathology of SIDS has been speculated (Dracker et al., 1992a; Morris et al, 1987). This work set out to test the theory that synergy between toxins produced by bacteria commonly found in the nasopharynges of SIDS victims could contribute to the outcome of SIDS. Bacterial toxins were prepared by a standard method and tested for lethality by intravenous injection into 11 day old chick embryos. Toxin preparations from 41 staphylococcal and 24 enterobacterial isolates were tested for lethality. Enterobacteria were more toxigenic than staphylococci (p <0.00001). Toxin preparations from 10 pairs of staphylococcal and enterobacterial isolates which were simultaneously from the nasopharynges of SIDS victims (n=7) or healthy controls (n=1) were tested together at sub-lethal concentrations. In 9/10 combinations lethality was significantly increased with respect to the lethality of the staphylococcal toxins, and in 8/10 combinations lethality was significantly increased with respect to the lethality of the enterobacterial toxins. Toxin preparations from 13 staphylococcal isolates at sub-lethal concentrations were tested together with pure endotoxin (20 ng/ml). In 11/13 combinations lethality was significantly increased with respect to the lethality of the bacterial toxins, and in 12/13 combinations lethality was significantly increased with respect to endotoxin. Toxin preparations from 13 staphylococcal isolates at sub-lethal concentrations were tested together with pure nicotine (800 ng/ml). In 13/13 combinations lethality was significantly increased. Toxin preparations from two pairs of staphylococcal and enterobacterial isolates which were sub-lethal when combined, were tested together with nicotine (800 ng/ml) and serially diluted. Lethality was significantly increased with increasing dilutions for both combinations. Semm from SIDS victims (n=11) and dead controls (n=5) were tested for lethality. Significantly more SIDS serum (10/11) were lethal compared to control serum (2/5; p=0.04). Lethal serum from SIDS victims (n=5) and controls (n=2) were tested in combination with HBSS, purified IgG (3% and 6% v/v) and normal human serum. The lethality of all serum samples were significantly decreased by combination with purified IgG (3% and 6% v/v) and normal human serum. Combination with HBSS significantly decreased the lethality of 2/5 SIDS semm and 1/2 control semm. Purified IgG (3% and 6% v/v) and normal human seram significantly decreased the lethality of nicotine (900 jLig/ml and 1 mg/ml) and endotoxin (40 ng/ml and 160 ng/ml). The effect of time postmortem upon endotoxin levels in rat organs (heart, kidney, liver and spleen) was investigated using a LAL assay (COATEST). Corpses were either stored for 0 h; 6 h at room temperature; or 6 h at room temperature followed by 24, 48, 72 or 98 h at refrigeration temperature. Injection of pure endotoxin into rats prior to death significantly increased the levels of endotoxin in the heart (p< 0.001), kidney (p< 0.001), liver (p<0.001) and spleen (p<0.001). In the kidney (p<0.001), liver (p<0.001) and spleen (p< 0.005) endotoxin levels significantly increased over the first 6 h of storage alone. Endotoxin levels in the heart significant increased (p<0.001) between 0 and 6 h storage, and between 6 and 54 h storage. The possible roles of bacterial toxins in SIDS is discussed. It is concluded that synergy can occur between toxins from Gram-positive and Gram-negative bacteria, endotoxin or nicotine, which could be a significant factor in the pathogenic mechanisms leading to SIDS. It is also concluded that lethal substance(s) in semm from SIDS victims and dead controls can be neutralised by purified IgG and normal human semm which may have vaccine potential. Finally, endotoxin levels in the kidney, liver and spleen but not the heart postmortem will only be significantly affected over the first 6 h storage at room temperature, further storage at refrigeration temperature has no significant effect.
Notlar:
School code: 1543
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684261.1) | 684261-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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