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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

MOLECULAR BIOLOGY OF GONOCOCCAL DEATH FOLLOWING EXPOSURE TO THE GRANULE EXTRACTS OF HUMAN NEUTROPHILS (NEISSERIA GONORRHOEAE, PEPTIDOGLYCAN, MEMBRANE DAMAGE).

ROCK, JOHN PATRICK. January 1986 (has links)
Gonococci that have been phagocytized by human neutrophils are killed very effectively. While much research has focused on defining the microbicidal mechanisms of the neutrophil arsenal, substantially less is known regarding why phagocytized bacteria die. Gonococci were examined, at the molecular level, following exposure to human neutrophil granule extracts (GE) in an effort to discover the "lethal lesion", that injury to the bacterial cell which results in its death. The cytoplasm-based metabolism of GE-treated gonococci continues to function normally for at least 30 minutes, although these same cells have lost the ability to divide and are reproductively dead. GE-treated gonococci were found to utilize less oxygen than control cells, indicative of damage to the cytoplasmic membrane. Visual examination of GE-treated gonococci by light microscopy revealed that the cells undergo very minimal division once exposed to GE. GE-treated gonococci visualized by transmission electron microscopy had outer membranes which suffered time-related disorganization and disruption; the effects began immediately upon contact with GE. GE-treatment was also observed to cause aberrant structure and orientation of forming bacterial septa. Investigation of gonococcal peptidoglycan, the structural component of the bacterial membrane, yielded interesting results when the effects of GE were scrutinized. GE caused subnormal incorporation of peptidoglycan precursors, and also induced a twofold higher rate of release of peptidoglycan turnover fragments than was seen from control cells. After analysis of peptidoglycan fragments released into culture supernatants by thin-layer chromatography and high-pressure liquid chromatography, it was found that the small amount of high-molecular-weight fragments exhausted by control cells was not present with treated cells. Investigation of the cell-associated peptidoglycan, by the above methods, after exposure to GE revealed differences in the digestion products. There was a distinct reduction in the amount of penicillin bound by the penicillin-binding proteins of GE-treated cells. There was, however, no observed change in the electrophoretic mobility between the PBPs of control and treated cells.
2

A small scale study evaluating allelic frequencies of human neutrophil antigens in Hong Kong Chinese population

Tam, Wai-kin, 譚偉健 January 2014 (has links)
Background: Human neutrophil antigens (HNA) are involved in a variety of clinical conditions such as transfusion related acute lung injury (TRALI), alloimmune neutropenia (ANN), autoimmune neutropenia (AIN). There are a total of five HNA systems, namely HNA-1, HNA-2, HNA-3, HNA-4 and HNA-5. In this decade, the allelic and genotypic frequencies of HNA were gradually evaluated in Europe, America and East Asia. [1] Despite HNA system being less polymorphic than HLA antigens, genotypic and allelic frequencies differences can still be observed in different geographical locations even of close proximity. For instance, studies in Thailand and China displayed genotypic and allelic frequencies differences. [2] These data highlights the fact that HNA genotypic and allelic frequencies vary among different populations even within the same region, however, the degree of variation remains to be elucidated. However, there is no information on HNA genotypic and allelic frequencies of Hong Kong population. Commercial genotyping kit has been available in the market but given its high reagent cost, it is not very popular in clinical laboratory. For this reason, a comparative affordable and economical in-house PCR-SSP assay was developed in this study. Aim The aim of this study is to evaluate the HNA genotyping and allelic frequencies in Hong Kong Chinese population by the development of an economical in-house PCR-SSP assay. Methods A commercial HNA typing kit was tested with reference samples to ensure this project has a standard and clinical compliance method for HNA genotyping prior to adopting in-house genotyping method. After reference protocol was established, in-house primers were designed and tested in parallel with the commercial method for validation purpose. After in-house method has been validated, 113 local samples were tested to calculate the genotype and allele frequencies in Hong Kong Chinese population using the developed in-house assay. Results A total of 113 Hong Kong Chinese samples were typed for HNA genotyping and results shown that: HNA-1a was 0.664; HNA-1b was 0.336; whereas HNA-1c allele was not detected. HNA-3a was 0.735 and HNA-3b was 0.265. HNA-4a was 0.991 and HNA-4b was 0.009. HNA-5a was 0.845 and HNA-5b was 0.155. Overall, results echoed with an earlier study performed on Han Chinese. [3] The genotyping frequency distribution for HNA-1, 3, 4 and 5 were: HNA-1a/a was 0.451, HNA-1 b/b was 0.124 and HNA-1 a/b was 0.425; HNA-3 a/a was 0.549, HNA-3a/b was 0.372 and HNA-3b/b was 0.08; HNA-4a/a was 0.982, HNA-4a/b was 0.018; HNA-5a/a was 0.708, HNA-5a/b was 0.274 and HNA-5b/b was 0.018. Conclusion This is the first study attempted to define HNA genotype and allelic frequencies by the self-developed in-house PCR-SSP method in Hong Kong Chinese population. The obtained results were comparable to those of gene frequencies in previous Xia’s study in Guangzhou Chinese population but significant difference from earliest reported European frequencies, confirming geographical difference exist. [3-5] However, due to small sample size in this study, further examination in larger sample may allow more representative frequencies for the Hong Kong population. / published_or_final_version / Pathology / Master / Master of Medical Sciences
3

Neutrophil priming : effects on pulmonary transit time and bio-distribution in vivo

Summers, Charlotte January 2011 (has links)
No description available.
4

Regulatory role of Semaphorin3E on human neutrophils migration

Saati, Abeer Abdullah 17 January 2013 (has links)
Semaphorin3E (Sema3E) is a secreted protein that was originally implicated in the development of the nervous system. However, its role in processes other than neuronal guidance is not fully understood. Sema3E interacts with the receptor PlexinD1 with high affinity. Furthermore, differential expression of PlexinD1 with neuropilin-1 (Nrp1) and Vascular Endothelial Growth Factor Receptor-2 (VEGFR2) determines pro-migratory or anti-migratory property of Sema3E. Recent studies demonstrated that semaphorins exhibit an inhibitory effect in most of inflammatory diseases. Among all inflammatory cells, neutrophils are an indispensable component of innate immunity and they are the foremost cells migrating to the site of inflammation. Substantial evidence indicated that the number of neutrophils is elevated in many inflammatory diseases. The aim of this study is to determine the expression pattern of Sema3E and its receptors, PlexinD1, Nrp1 and VEGFR2 in human neutrophils and to investigate the role of Sema3E on neutrophils’ migration. Here we found that isolated human neutrophils, from peripheral blood of healthy volunteers, constitutively express Sema3E and its receptors PlexinD1 and VEGFR2 at both protein and mRNA level; however, Nrp1 expression was not detected in these cells. Additionally, Sema3E display a potent ability to inhibit CXCL8/IL-8 induced neutrophils migration as determined by transwell in vitro system and microfluidic device coupled to real-time microscopy. Our data showed that Sema3E modulates the migration of neutrophils induced by the most potent chemoattractant stimuli, CXCL8/IL-8, suggesting an important regulatory role of this pathway in inflammatory diseases associated with neutrophilia.
5

Regulatory role of Semaphorin3E on human neutrophils migration

Saati, Abeer Abdullah 17 January 2013 (has links)
Semaphorin3E (Sema3E) is a secreted protein that was originally implicated in the development of the nervous system. However, its role in processes other than neuronal guidance is not fully understood. Sema3E interacts with the receptor PlexinD1 with high affinity. Furthermore, differential expression of PlexinD1 with neuropilin-1 (Nrp1) and Vascular Endothelial Growth Factor Receptor-2 (VEGFR2) determines pro-migratory or anti-migratory property of Sema3E. Recent studies demonstrated that semaphorins exhibit an inhibitory effect in most of inflammatory diseases. Among all inflammatory cells, neutrophils are an indispensable component of innate immunity and they are the foremost cells migrating to the site of inflammation. Substantial evidence indicated that the number of neutrophils is elevated in many inflammatory diseases. The aim of this study is to determine the expression pattern of Sema3E and its receptors, PlexinD1, Nrp1 and VEGFR2 in human neutrophils and to investigate the role of Sema3E on neutrophils’ migration. Here we found that isolated human neutrophils, from peripheral blood of healthy volunteers, constitutively express Sema3E and its receptors PlexinD1 and VEGFR2 at both protein and mRNA level; however, Nrp1 expression was not detected in these cells. Additionally, Sema3E display a potent ability to inhibit CXCL8/IL-8 induced neutrophils migration as determined by transwell in vitro system and microfluidic device coupled to real-time microscopy. Our data showed that Sema3E modulates the migration of neutrophils induced by the most potent chemoattractant stimuli, CXCL8/IL-8, suggesting an important regulatory role of this pathway in inflammatory diseases associated with neutrophilia.
6

The purification of peripheral blood eosinophils and neutrophils and the characterization and comparison of the luminol-dependent chemiluminescence response in cells isloated from normal and allergic subjects

Shult, Peter A. January 1984 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.
7

Die teenwoordigheid van histamien H3-reseptore op limfosiete en neutrofiele

Le Roux, Susanna Magdalena. January 2005 (has links)
Thesis (MSc. (Pharmacology, Faculty of Medicine))--Universiteit van Pretoria, 2000. / Summary in Afrikaans.
8

Inflammation-induced migration of neutrophils across the lymphatic endothelium

Rigby, David Andrew January 2011 (has links)
The lymphatic system provides a conduit for the trafficking of immune cells from the periphery to draining lymph nodes, both for constitutive immune surveillance and during inflammation. Thus, leucocyte migration into the lymphatics represents an important step in the initiation of a primary immune response, which occurs within lymph nodes. Traditionally, it has been considered that neutrophils are absent from the afferent lymph, having a finite lifespan in the periphery after extravasation from the blood. However, recent research has reported the presence of neutrophils in lymph nodes, in animal models of infection, where neutrophil trafficking was found to occur through afferent lymphatic vessels. This thesis examines the mechanisms regulating neutrophil migration, both by the lymphatic endothelium and neutrophils themselves, under resting and inflammatory conditions. Primary human dermal lymphatic endothelial cells (HDLECs) respond to the pro- inflammatory cytokine, TNF-α by instigating a distinct expression programme, characterised by the up-regulation of various adhesion molecules (ICAM-1, VCAM-1, E-selectin), and CXC- chemokines (ENA-78, GROβ, IL-8), as well as other potential regulators of neutrophil entry such as constitutively expressed adhesion molecules, CD99 and ESAM. Moreover, neutrophils possess counter-receptors for these adhesion molecules and contain basement membrane-specific proteases (elastase) and matrix metalloproteinases (MMPs) such as MMPs -8 and -9, localised in intracellular granules, ready to be exocytosed upon inflammatory stimuli. In vitro data presented in this thesis demonstrate that neutrophil adhesion and transmigration of the lymphatic endothelium is entirely dependent on prior activation of the monolayer with TNF-a. Furthermore, the aforementioned lymphatic-expressed adhesion molecules and chemokines, as well as neutrophil-derived proteases and MMPs are shown to play critical roles in neutrophil adhesion and transmigration of the lymphatic endothelium. Subsequent in vivo experiments confirmed that neutrophil trafficking to lymph nodes across lymphatic vessels is wholly dependent on prior vaccination with Mycobacterium bovis Bacillus Calmette-Guerin (BCG) Tokyo-172. Moreover, neutrophils trafficking to lymph nodes across lymphatic vessels are shown to require ICAM-1. The results described in this thesis provide the first evidence that both the lymphatic endothelium and neutrophils act in concert to regulate entry to lymph nodes and determine the outcome of infection, or vaccination.
9

Neutrophil function tests in Chinese newborn infants

Wan, Shek-kong, Thomas. January 1991 (has links)
Thesis (M.Phil.)--University of Hong Kong, 1992. / Also available in print.
10

CHARACTERIZATION OF HUMAN POLYMORPHONUCLEAR NEUTROPHIL PHAGOLYSOSOMES.

Fowler, Rosalie Ahumada León. January 1983 (has links)
No description available.

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