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Partial purification and characterisation of a wheat N-acetyl-#beta#-D-hexosaminidase and its role in defensive lignin depositionJordan, Nicholas David January 1994 (has links)
No description available.
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Characterisation of the immune response in otitis mediaSaleh, Nadeh S., n/a January 2002 (has links)
Acute otitis media is the most common illness diagnosed during early childhood that
can cause significant morbidity (Brook, 1994) and sometimes can cause irreversible
sequelae such as a hearing defect and subsequent learning difficulties (Klein, 1994). The
aims of the research presented here were to study some aspects of the middle ear
defence mechanisms in both immune and non-immune rats following experimental
otitis media (OM) with two pathogens nontypeable Haemophilus influenzae (NTHi) and
Moraxella catarrhalis (M. catarrhalis). This study also aimed at developing a suitable
technique for preparing immunohistochemical staining of middle ear sections (chapter
2).
A previous study has shown that a regime where rats received an IPP immunisation
combined with an IT boost was effective in enhancing clearance of a middle ear
infection with the same strain of NTHi and also in the presence of a concomitant viral
infection (Moore et al, 2001). Results of this study have shown that for NTHi infection
a distinct cellular influx to the middle ear in the immune rats was accompanied by an
enhanced bacterial clearance compared to the non-immunised rats (chapter 3). This
cellular influx was responsible for the remarkable reduction in the bacterial number.
The sharp decline in PMNs numbers in the NTHi immunised rats that followed
complete bacterial clearance at 72h post infection (Table 3.1) indicate a more
effectively controlled down regulation of this cell infiltrate than the non-immunised rats.
For M. catarrhalis infection, there was no difference in cell infiltrate between immune
and non-immune rats, but enhanced clearance of the bacteria were observed for the
immune animals.
The histopathological changes in the middle ear mucosa of rats with experimentally
induced infection were studied to provide a better understanding about the distribution
of the inflammatory cells and changes in the mucosa during the first 24h post challenge
with NTHi and M. catarrhalis (Chapter 4). These changes have not been previously
studied for the two pathogens at 24h post challenge in rats. Induced infections with the
two pathogens were found to produce similar histopathological changes but more
inflammatory infiltration was observed within the infected mucosa with NTHi than that
seen with M. catarrhalis. The infections were characterized by increased thickness of
the middle ear mucosa, Eustachian tube mucosa, periosteum and tympanic membrane.
There was also an increase in the number and size of small blood vessels at all sites, and
these small blood vessels seem to be the source of the inflammatory infiltration into the
middle ear mucosa and middle ear cavity during the infection. These findings provided
an essential background to the immunohistochemical study.
The effect of mucosal immunisation on the distribution of CD4+T cells and CD8+T
cells has not been investigated previously. Results of the present study (Chapter 5) show
the pattern of distribution of these cells during the first 48h post infection with NTHi in
the rat. The number of CD4+and CD8+T cells peaked at 24h post infection in the nonimmunised
animal and were highest at 48h post-infection in the immunised rats. The
difference in response in the immunised rats may represent regulation of the
inflammatory response by the immune system. The inflammatory response regulation is
indicated by the difference in cellular influx into the immune rats and the response in
the immune rats that corresponds to enhanced bacterial clearance prior to a decrease in
numbers of inflammatory cells once the bacteria was no longer detected (Chapter 3).
This resolution of the inflammatory mass would reduce the opportunity for continued
damage to local tissue. These changes are also supported by the reduction in the
thickness of the middle ear mucosa of the immunised rats especially at 24h and 48h
post-infection (Chapter 5).
This study has shown that there are distinct differences in the rate of bacterial clearance
and cellular changes in the middle ear mucosa and tympanic bulla in immunised rats
during a middle ear infection. Future studies are still required to gain a better
understanding of differences in the inflammatory response for both pathogens, NTHi
and M. catarrhalis.
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Pathogenesis-related proteins in barley : localization and accumulation patterns in response to infection by Bipolaris sorokiniana /Santén, Kristina, January 2007 (has links) (PDF)
Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2007. / Härtill 4 uppsatser.
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Immune cell responses to the cattle lungworm, Dictyocaulus viviparus /Hagberg, Malin, January 2008 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 3 uppsatser.
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Surface structure, wax and methanol-extractable compounds in Scots pine and Norway spruce needles enhanced UV-BKinnunen, H. (Heli) 30 May 1999 (has links)
Abstract
Increased amounts of epicuticular waxes and UV-absorbing compounds, such as flavonoids, and smaller leaf/needle surface area are plant defence mechanisms against UV-B radiation. The response of the needle epicuticular waxes of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies Karst.) seedlings to increased UV-B were investigated in short-term and long-term greenhouse experiments. In a more realistic long-term field experiment with mature Scots pines, the methanol-extractable UV-absorbing compounds were also analysed.
Some significant changes were observed in the wax tube distribution (WTD, %) and the amount of waxes in Norway spruce seedlings in the short-term Belgian greenhouse experiment (UV-BBE 0, 11.3 and 22.6 kJ m-2 d-1), but no changes were detected in Scots pine seedlings. No changes in waxes were observed in the long-term Finnish greenhouse experiment (UV-BBE 0, 2.2–6.6 and 5.6–16.8 kJ m-2 d-1), where both the Norway spruce and the Scots pine seedlings seemed to respond by having smaller needle surface areas. A field experiment (UV-BBE 0.5–2.4 kJ m-2 d-1 and 0.7–5.1 kJ m-2 d-1) with mature Scots pines revealed no significant changes in WTD during the three growing seasons or the amount of waxes during the third growing season.
In the long-term field experiment the amount of UV-absorbing compounds varied significantly between seasons and/or needle age classes. Elevated amounts of these compounds were already observed in the three-day-old needles and also in the oldest (c + 2) needles when the waxes were still undeveloped or already somewhateroded. No significant differences in the amount of UV-absorbing compounds were observed between the treatments during the first and second growing seasons. During the third growing season, needles of all ages contained significantly or slightly less UV-absorbing compounds in supplemental UV-B than in the ambient treatment, possibly due to cumulative effects of UV-B in already inhibited pigment synthesis. This suggests that these defence mechanisms are not efficient enough to prevent the UV-B-induced damage in the long term.
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Properties of Escherichia coli in recurrent urinary tract infectionBrooks, Heather Joan Linton January 1976 (has links)
Properties of Escherichia coli considered to be of importance in overcoming host defence mechanisms against urinary tract infection (OTI) were investigated. These were: 1) 0 and H serotype 2) K antigen content 3) Sensitivity to the bactericidal activity of human serum 4) Haemolysin production 5) Fimbriae production 6) Fermentation of sucrose, salicin and dulcitol 7) Sensitivity to serine, spermine and urea 8) Growth requirements 9) Mucinase production Ecoli strains isolated from normal subjects and patients attending the Nephrourological Clinic at St. Bartholomew's Hospital because of known or suspected UTI, were studied. Strains isolated from urines more frequently belonged to 0 serogroups 2,4,6,8,18ab and 75, had high K antigen titres, were haemolytic and fimbriate, and fermented salicin than periurethral strains from normal subjects. These findings support the concept of "special pathogenicity", that certain strains are more invasive for the urinary tract than others. Strains rich in these "pathogenic properties" were rarely isolated from normal subjects but were significantly more frequently isolated from periurethral swabs of patients. Periurethral strains from symptomatic, abacteriuric (urethral syndrome) patients were similar to those from bacteriuric patients when they were between infections. Previous work has not implicated bacteria in the aetiology of most cases of this disease and this finding remains unexplained. Strains isolated from the upper tracts of patients undergoing localisation tests more frequently exhibited pathogenic properties than those isolated from only the lower tract, and this was considered to reflect the superior ability of these strains to reach the upper tract or better combat host defence mechanisms.
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Molecular mapping of potyvirus resistance genes in diploid potatoes /Hämäläinen, Jaana. January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 3 uppsatser.
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Defences and responses : woody species and large herbivores in African savannas /Rooke, Tuulikki, January 2003 (has links) (PDF)
Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 5 uppsatser.
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Genes and mechanisms in Arabidopsis innate immunity against Leptosphaeria maculans /Staal, Jens, January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.
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Functional and dysfunctional retention: the impact of trust and cynicism /Peddie, Sarah Kathryn, January 1900 (has links)
Thesis (M.A.) - Carleton University, 2007. / Includes bibliographical references (p. 79-93). Also available in electronic format on the Internet.
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