by Kwan, Leo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 108-116). / Abstract --- p.i / Achnowledgment --- p.ii / List of abbreviations --- p.iii / List of table and figures --- p.v / Table of contents --- p.vi / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- THE DISCOVERY OF TUMOUR NECROSIS FACTOR (TNF) --- p.1 / Chapter 1.2 --- THE MOLECULE AND ITS RECEPTORS --- p.1 / Chapter 1.3 --- THE BIOLOGICAL ACTIVITIES OF TNF --- p.3 / Chapter 1.4 --- STUDIES ON THE CYTOTOXIC MECHANISM OF TNF --- p.4 / Chapter 1.5 --- A TENTATIVE MECHANISM OF TNF CYTOTOXICITY --- p.11 / Chapter 1.6 --- THE GLUTATHIONE SYSTEM : A CELLULAR PROTECTIVE MECHANISM AGAINST OXIDATIVE STRESS …… --- p.12 / Chapter 1.7 --- OBJECTIVE AND STRATEGY OF THIS STUDY --- p.16 / Chapter CHAPTER 2 --- MATERIALS AND APPARATI / Chapter 2.1 --- CELL LINES --- p.19 / Chapter 2.2 --- "ISOLATION, MAINTENANCE AND SUBCULTURE OF CELL LINES" --- p.19 / Chapter 1. --- Plain RPMI-1640 medium / Chapter 2. --- Penicillin-streptomycin solution / Chapter 3. --- Foetal bovine serum / Chapter 4. --- Complete RPMI-1640 medium / Chapter 5. --- Trypsin-ethylenediaminetetraacetate solution / Chapter 6. --- Phosphate buffered saline / Chapter 7. --- Cycloheximide / Chapter 8. --- Actinomycin D / Chapter 9. --- Trypan blue stain / Chapter 10. --- Neutral red stain / Chapter 11. --- Recombinant human tumour necrosis factor / Chapter 12. --- Cell culture plates and flasks / Chapter 2.3 --- GROWTH CHARACTERISTIC --- p.22 / Chapter 1. --- Tritiated Thymidine / Chapter 2. --- Tritiated Leucine / Chapter 3. --- Trichloroacetic acid / Chapter 4. --- Scintillation cocktail / Chapter 2.4 --- "RESPONSE TOWARDS ANTICANCER DRUGS, CYTOTOXIC AGENTS, AND ENZYME MODULATORS" --- p.23 / Chapter 1. --- N-acetyl-DL-homocysteinethiolactone / Chapter 2. --- Diethyldithiocarbamic acid / Chapter 3. --- Doxorubicin / Chapter 4. --- Acivicin / Chapter 5. --- Ethacrynic acid / Chapter 6. --- "L'Buthionine-[S,R]-sulfoximine" / Chapter 7. --- Hydrogen peroxide / Chapter 8. --- Methotrexate / Chapter 9. --- Menadione / Chapter 2.5 --- CULTURE OF BACTERIAL CELLS --- p.27 / Chapter 1. --- Ampicillin stock solution / Chapter 2. --- Chloramphenicol stock solution / Chapter 3. --- Tetracycline stock solution / Chapter 4. --- Luria-Bertani medium / Chapter 5. --- LB with ampicillin / Chapter 6. --- SOB medium / Chapter 7. --- SOB medium with ampicillin / Chapter 8. --- SOC medium / Chapter 9. --- SB medium / Chapter 10. --- SB medium with ampicillin / Chapter 11. --- Agar plates / Chapter 2.6 --- PREPARATION OF DNA PROBES FROM BACTERIAL CLONES --- p.29 / Chapter 1. --- FlexiPrep Kit / Chapter 2. --- Restriction endonucleases / Chapter 3. --- GeneClean® II Kit / Chapter 4. --- cDNA clones for making DNA probes / Chapter 5. --- TrisHCl EDTA buffer / Chapter 2.7. --- ELECTROPHORESIS OF DNA --- p.31 / Chapter 1. --- EDTA stock solution / Chapter 2. --- Tris acetate EDTA electrophoresis buffer / Chapter 3. --- Tris borate EDTA electrophoresis buffer / Chapter 4. --- Ethidium bromide / Chapter 5. --- DNA molecular size markers / Chapter 6. --- TAE/TBE agarose gel slab / Chapter 2.8 --- CONSTRUCTION OF MURINE TNFR1 PARTIAL cDNA CLONE --- p.33 / Chapter 1. --- Frist strand cDNA synthesis Kit / Chapter 2. --- Murine TNFR1 forward and reverse primers / Chapter 3. --- Polymerase chain reaction reagents / Chapter 4. --- Cloning vector / Chapter 5. --- Modifing enzymes / Chapter 6. --- T7 SequencingTM Kit / Chapter 7. --- Acrylamide/bis gel stock solution / Chapter 8. --- Urea / Chapter 9. --- TEMED and ammonium persulphate / Chapter 10. --- β-Galactosidase colour test reagents / Chapter 11. --- TFB solution / Chapter 12. --- DnD solution / Chapter 2.9. --- RADIOLABELLING OF DNA PROBES --- p.35 / Chapter 1. --- Oligolabelling kit / Chapter 2. --- Redivue [α-32P] dCTP / Chapter 3. --- PUSH column / Chapter 2.10 --- EXTRACTION OF TOTAL RNA FROM CELL LINES --- p.36 / Chapter 1. --- N-Lauroylsarcosine / Chapter 2. --- 2M sodium acetate (pH48) / Chapter 3. --- Phenol / Chapter 4. --- Isopropanol / Chapter 5. --- Ethanol / Chapter 6. --- Extraction buffer / Chapter 7. --- Chloroform / Chapter 8. --- Isoamyl alcohol / Chapter 2.11 --- HYBRIDIZATION AND NORTHERN ANALYSIS --- p.37 / Chapter 1. --- 20XSSC / Chapter 2. --- 5X formaldehyde running buffer / Chapter 3. --- RNA sample buffer / Chapter 4. --- 10X RNA loading buffer / Chapter 5. --- Formaldehyde slab gel / Chapter 6. --- Hybond®-N membrane / Chapter 7. --- Immobilon®-N membrane / Chapter 8. --- Salmon sperm DNA / Chapter 9. --- Sodium dodecyl sulphate / Chapter 10. --- Dextran sulphate / Chapter 11. --- Kodak Biomax MR and X-OMAT films and developing kits / Chapter 2.12 --- APPARATI USED --- p.39 / Chapter CHAPTER 3 --- METHODS / Chapter 3.1 --- ISOLATION AND MAINTENANCE OF TNF RESISTANT L929 CELLS --- p.40 / Chapter 3.1.1 --- Culture of L929 cells / Chapter 3.1.2 --- Trypan blue exclusion test / Chapter 3.1.3 --- Isolation of TNF-resistant variants of L929 / Chapter 3.1.4 --- Verification of the TNF-resistant trait of rL929 / Chapter 3.1.5 --- Neutral red uptake assay / Chapter 3.2 --- COMPARING L929 AND rL929 CELLS IN TERMS OF GROWTH CHARACTERISTICS --- p.43 / Chapter 3.2.1 --- Doubling time / Chapter 3.2.2 --- Rate of protein synthesis / Chapter 3.2.3 --- Rate of DNA synthesis / Chapter 3.3 --- COMPARING L929 AND rL929 CELLS IN TERMS OF RESPONSE TOWARDS DIFFERENT ENZYME INHIBITORS AND CYTOTOXIC AGENTS --- p.44 / Chapter 3.3.1 --- TNF cytotoxicity on L929 and rL929 cells --- p.44 / Chapter 3.3.2 --- Effects of inhibitors of gene transcription and protein synthesis on TNF cytotoxicity on L929 and rL929 cells --- p.44 / Chapter 3.3.3 --- Cytotoxic effect of hydrogen peroxide and menadione on L929 and rL929 cells --- p.44 / Chapter 3.3.4 --- TNF cytotoxicity on L929 and rL929 cells: effect of N-acetyl homocysteine thiolatone --- p.45 / Chapter 3.3.4.1 --- The tolerant limit of AHCT / Chapter 3.3.4.2 --- Effect of AHCT on TNF cytotoxicity / Chapter 3.3.5 --- TNF cytotoxicity on L929 and rL929 cells: effect of diethyldithiocarbamate --- p.46 / Chapter 3.3.5.1 --- The tolerant limit of DEDTC / Chapter 3.3.5.2 --- Effect of DEDTC on TNF cytotoxicity / Chapter 3.3.6 --- TNF cytotoxicity on L929 and rL929 cells: effect of buthionice sulfoximine --- p.47 / Chapter 3.3.6.1 --- The tolerant limit of BSO / Chapter 3.3.6.2 --- Effect of BSO on TNF cytotoxicity / Chapter 3.3.7 --- TNF cytotoxicity on L929 and rL929 cells: effect of Acivicin --- p.47 / Chapter 3.3.7.1 --- The tolerant limit of acivicin / Chapter 3.3.7.2 --- Effect of acivicin on TNF cytotoxicity / Chapter 3.3.8 --- TNF cytotoxicity on L929 and rL929 cells: effect of ethacrynic acid --- p.48 / Chapter 3.3.8.1 --- The tolerant limit of ethacrynic acid / Chapter 3.3.8.2 --- Effect of ethacrynic acid on TNF cytotoxicity / Chapter 3.3.9 --- Cytotoxic effect of doxorubicin on L929 and rL929 cells --- p.49 / Chapter 3.3.10 --- TNF cytotoxicity of L929 cells: effect of N-acetyl cysteine --- p.49 / Chapter 3.3.11 --- Cytotoxic effect of methotrexate on L929 and rL929 cells --- p.50 / Chapter 3.3.12 --- Cytotoxic effect of hyperthermia on L929 and rL929 cells --- p.50 / Chapter 3.4 --- NORTHERN ANALYSIS AND HYBRIDIZATION --- p.51 / Chapter 3.4.1. --- Preparing RNA blots --- p.51 / Chapter 3.4.1.1 --- Extraction of total RNA from cells / Chapter 3.4.1.2 --- Making equal loading of RNA samples in formaldehyde gel electrophoresis / Chapter 3.4.1.3 --- Northern blotting of RNA / Chapter 3.4.2. --- Preparation of cDNA probes --- p.53 / Chapter 3.4.2.1 --- Preparing plasmids from A TCC clones / Chapter 3.4.2.2 --- Preparing TNFR1 probe from first-strand cDNA of L929 cells / Chapter 1. --- Construction of recombinant clone from the PCR product of TNFRl fragment / Chapter 2. --- Transforming the recombinant vector into JM109 host / Chapter 3. --- Sequencing of PCR product for identity confirmation / Chapter 3.4.2.3 --- Preparing DNA inserts from plasmids / Chapter 3.4.3 --- Radiolabelling of cDNA probes --- p.56 / Chapter 3.4.4 --- Hybridization of radioactive probes to RNA blots --- p.57 / Chapter CHAPTER 4 --- RESULTS AND DISCUSSIONS / Chapter 4.1 --- ISOLATION OF TNF-RESISTANT VARIANTS OF L929 CELLS --- p.58 / Chapter 4.1.1 --- Single cell subcloning of TNF-resistant L929 variants / Chapter 4.1.2 --- Growth rates of L929 and rL929 cells / Chapter 4.1.3 --- Rate of protein synthesis in L929 and rL929 cells / Chapter 4.1.4 --- Rate of DNA synthesis in L929and rL929 cells / Chapter 4.2 --- EFFECT OF INHIBITORS OF GENE TRANSCRIPTION AND PROTEIN SYNTHESIS ON TNF CYTOTOXICITY ON L929 AND rL929 CELLS --- p.67 / Chapter 4.3 --- RESPONSE OF L929 AND rL929 CELLS TOWARDS VARIOUS CYTOTOXIC AGENTS --- p.70 / Chapter 4.3.1 --- "Response towards methotrexate, an anti-metabolite used in cancer treatment" / Chapter 4.3.2 --- "Response towards doxorubicin, an chemotherapeutic agent used in cancer treatment" / Chapter 4.3.3 --- "Response towards menadione, a cytotoxic agent known to generate free radicals inside cells" / Chapter 4.3.4 --- Response towards hydrogen peroxide: a highly oxidative agent / Chapter 4.3.5 --- "Response towards hyperthermia, a treatment known to exert oxidative stress on cells" / Chapter 4.4 --- EFFECTS OF MODULATORS OF CYTOSOLIC SUPEROXIDE DISMUTASE ON TNF CYTOTOXICITY ON L929 and rL929 CELLS --- p.77 / Chapter 4.5 --- EFFECT OF MODULATORS OF GLUTATHIONE METABOLISM ON TNF CYTOTOXICITY ON L929 AND rL929 CELLS --- p.82 / Chapter 4.5.1 --- "Effects of L-buthionine [S,R] sulfoximine, an inhibitor of glutathione synthesis" --- p.82 / Chapter 4.5.2 --- "Effect of N-acetyl cysteine, a cysteine derivative" --- p.84 / Chapter 4.5.3 --- "Effects of acivicin , an inhibitor of GSH reuptake and recycle" --- p.85 / Chapter 4.5.4 --- "Effect of ethacrynic acid, an inhibitor of glutathione S- transferase" --- p.87 / Chapter 4.6 --- GENE EXPRESSION IN L929 AND rL929 CELLS IN THE COURSE OF TNF CHALLENGE --- p.89 / Chapter 4.6.1 --- Isolation of total RNA from L929 and rL929 cells --- p.89 / Chapter 4.6.2 --- Preparation of DNA probes for hybridization --- p.89 / Chapter 4.6.3 --- Hybridization of specific probes on RNA blots --- p.90 / Chapter 4.6.3.1 --- Expression of heat shock protein --- p.70 / Chapter 4.6.3.2 --- Expression of the p55 TNF receptor / Chapter 4.6.3.3 --- Expression of glutathione reductase / Chapter 4.6.3.4 --- Expression of glutathione S-transferase pi / Chapter 4.7 --- DISCUSSIONS OF THE EXPERIMENTAL RESULTS --- p.97 / Chapter CHAPTER 5 --- GENERAL DISCUSSION --- p.104 / APPENDIX / Generation of the TNF receptor 1 cDNA probe --- p.106 / REFERENCES --- p.108

by Suk-Fung Tsang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 101-112). / Abstract --- p.i / Acknowledgement --- p.iii / Abbreviation --- p.iv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- TNF molecule / Chapter 1.2 --- Molecular biosynthesis of TNF / Chapter 1.3 --- Antitumor activity of TNF / Chapter 1.4 --- Macrophage-mediated immunity / Chapter 1.5 --- Endogenous production of TNF / Chapter 1.6 --- LPS : the potent inducer for TNF release / Chapter 1.7 --- Natural product: as primer or inducer / Chapter 1.8 --- Aim of this project / Chapter Chapter 2 --- Materials and Methods --- p.22 / Chapter 2.1 --- Materials / Chapter 2.2 --- Animals / Chapter 2.3 --- Cell line / Chapter 2.4 --- Transformed cell line : EAT cells invivo / Chapter 2.5 --- Reagents / Chapter 2.6 --- Methods / Chapter Chapter 3 --- Preparation of sample --- p.33 / Chapter 3.1 --- Alcohol precipitaion of Bupleuri radix / Chapter 3.2 --- Endogenous TNF production by BR fractions / Chapter Chapter 4 --- Purification of BRI --- p.38 / Chapter 4.1 --- Gel filtration chromatography of BRI / Chapter 4.2 --- Anion exchange chromatography / Chapter Chapter 5 --- Purification of PQI --- p.52 / Chapter 5.1 --- Gel filtration chromatography of PQI / Chapter 5.2 --- Anion exchange chromatography / Chapter Chapter 6 --- Capacity of BR and PQ as eliciting agent for endogenous TNF production --- p.62 / Chapter 6.1 --- Time course of endogenous TNF production by BRI subfractions / Chapter 6.2 --- Time course of endogenous TNF production by PQI subfractions / Chapter 6.3 --- BRI subfractions as eliciting agents / Chapter 6.4 --- PQI subfractions as eliciting agents / Chapter Chapter 7 --- Are BR and PQ priming agents in endogenous TNF production ？ --- p.71 / Chapter 7.1 --- Priming by intraperitoneal route / Chapter 7.2 --- Priming by intravenous route / Chapter Chapter 8 --- Removal of LPS by acetic acid treatment --- p.79 / Chapter Chapter 9 --- Antitumor activities of BRI subfractionsin relationship with TNF production --- p.86 / Chapter 9.1 --- BRI subfraction as eliciting agent / Chapter 9.2 --- Pretreatment with BRIA subfractions followed by LPS treatment / Chapter Chapter 10 --- Conclusion --- p.95 / Bibliography --- p.101

"July 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Tumour necrosis has long been associated with poor prognosis and reduced survival in cancer. Hypotheses to explain this include the idea that as aggressive tumours tend to grow rapidly, they outgrow their blood supply leading to areas of hypoxia and subsequently necrosis. However whilst this and similar hypotheses have been put forward to explain the association, the biological significance of the cells which make up necrotic tissue has been largely ignored. This stems from the belief that because a tumour is more aggressive and fast growing it develops areas of necrosis, rather than, the tumour is more aggressive because it contains areas of necrosis. Which came first like the egg and chicken is yet to be determined, however to date most research has only considered the possibility of the former. Viable cells were found in the necrotic core of Multicellular Tumour Spheroids. When examined these cells were found to be different to the original cell line in terms of proliferation, migration, and chemosensitivity. A proteomic analysis showed that these phenotypical changes were accompanied by changes in a large number of proteins within the cells, some of which could be potential therapeutic targets. Furthermore this has led to a new hypothesis for tumour necrosis and its association with poor prognosis. Necrotic tissue provides a microenvironemental niche for cells with increased survival capabilities. Protected from many chemotherapeutics by their non-proliferative status once conditions improve these cells can return to proliferation and repopulate the tumour with an increasingly aggressive population of cells.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O objetivo do presente estudo foi verificar os efeitos da L-alanil-glutamina (Ala-Gln) na isquemia e reperfusÃo em cÃrebro de ratos. Foram utilizados 48 ratos machos, da linhagem Wistar, com idade mÃdia de 62 dias e peso mÃdio de 276,38g, distribuÃdos em quatro grupos: Sham 30 minutos, Isquemia, Sham 90 minutos e Isquemia/ ReperfusÃo. Foi utilizado um modelo de isquemia cerebral experimental global, com oclusÃo da artÃria carÃtida comum bilateral e administraÃÃo de soluÃÃo salina ou Ala-Gln. Os resultados do presente estudo mostraram elevaÃÃo estatisticamente significante no percentual de Ãrea de necrose do grupo Isquemia (13,24  8,82) em relaÃÃo ao grupo Sham 30 minutos (0,12  0,20, p= 0,01). O mesmo ocorreu em relaÃÃo à Ãrea de necrose do grupo Isquemia/ReperfusÃo (13,30  9,91) em relaÃÃo ao Sham 90 minutos (0,70  1,35, p= 0,01). Tais resultados demonstram a efetividade do modelo Isquemia e Isquemia/ReperfusÃo cerebrais utilizados. NÃo foi observada alteraÃÃo significante no percentual de Ãrea de necrose entre os grupos Isquemia Salina (13,24  8,82) e Isquemia Ala-Gln (15,35  6,80, p= 0,34). A mÃdia do percentual de Ãrea isquÃmica do grupo Isquemia/ReperfusÃo Ala-Gln (4,65  1,44) foi significantemente inferior Ãquela encontrada no grupo Isquemia/ReperfusÃo Salina (13,30  9,91, p= 0,03). A administraÃÃo prÃvia de Ala-Gln a ratos submetidos à Isquemia/reperfusÃo cerebral nÃo promoveu reduÃÃo no percentual de Ãrea de necrose na lesÃo isquÃmica. Por outro lado, esse dipeptÃdeo reduziu o percentual de necrose cerebral na lesÃo Isquemia/ReperfusÃo cerebral. / The aim of this study was to investigate the effects of L-alanyl-glutamine (Ala-Gln) in ischemia and reperfusion in rat brain. We used 48 male rats, Wistar, with a mean age of 62 days and average weight of 276.38 g, divided into four groups: Sham 30 minutes ischemia, 90 minutes and Sham Ischemia / Reperfusion. We used a model of experimental global cerebral ischemia with occlusion of bilateral common carotid artery and administration of saline or Ala-Gln. The results of this study showed a statistically significant increase in the percentage of necrotic area of the ischemia group (13.24  8.82) than in group Sham 30 minutes (0.12  0.20, p= 0.01). The same occurred in relation to the area of necrosis in ischemia-reperfusion group (13.30  9.91) compared to Sham 90 minutes (0.70  1.35, p= 0.01). These results demonstrate the effectiveness of the model Ischemia and Ischemia / Reperfusion brain used. There was no significant change in the percentage of necrotic area between Salina ischemia groups (13.24  8.82) and ischemia Ala-Gln (15.35  6.80, p= 0.34). The average percentage of ischemic area of group Ischemia / Reperfusion Ala-Gln (4.65  1.44) was significantly lower than that in group Ischemia / Reperfusion Salina (13.30  9.91, p= 0.03). The prior administration of Ala-Gln in rats subjected to ischemia / reperfusion did not cause reduction in the percentage of necrosis in ischemic injury. Moreover, this dipeptide reduced the percentage of necrosis in the cerebral injury cerebral ischemia / reperfusion.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Um dos principais objetivos do tratamento endodÃntico dos canais radiculares de dentes com polpa necrÃtica consiste em eliminar os microorganismos localizados no sistema de canais radiculares. Dessa forma, esta dissertaÃÃo, constituÃda por um artigo, propÃe-se a avaliar o efeito antibacteriano do preparo quÃmico-mecÃnico e de uma pasta à base de hidrÃxido de cÃlcio sobre bactÃrias presentes em canais radiculares de dentes decÃduos necrosados apÃs trauma bem como verificar a presenÃa dos microorganismos Fusobacterium nucleatum e bacilo pigmentado negro nestes dentes. Seguindo os critÃrios de inclusÃo, a amostra consistiu de 18 dentes, totalizando 14 pacientes. As coletas microbiolÃgicas foram realizadas apÃs a abertura coronÃria (C1) e 72h apÃs a remoÃÃo da medicaÃÃo intracanal (C3), sendo que, para 10 dentes, realizou-se outra coleta apÃs a instrumentaÃÃo (C2). As coletas foram realizadas introduzindo-se sequencialmente 3 cones de papel absorvente estÃril, de diÃmetro visualmente compatÃvel com o do canal radicular, no interior deste por aproximadamente 1 minuto. ApÃs este intervalo, os cones foram removidos, transferidos para um tubo contendo um fluido reduzido para transporte e levados ao laboratÃrio para processamento microbiolÃgico. Na C1, os microorganismos foram isolados em 17/18 (94,4%) dos canais radiculares, sendo a mÃdia de CFUs de 5.4 x 105, na C2, em apenas 1/10 (10%) canal radicular, com uma mÃdia de 4.3 x 102, e na C3 em 15/18 (83.3%), com mÃdia de 1.5 x 105. Houve uma diferenÃa estatisticamente significante entre C1 e C2, o mesmo nÃo ocorrendo entre C1 e C3 e entre C2 e C3. O microorganismo Fusobacterium nucleatum e o bacilo pigmentado negro foram observados em 55.5% (10/18) e 11.1% (2/18), respectivamente, na C1, nÃo sendo detectados na C2, e na C3 estavam presentes em 16.6% (3/18) e 5.5% (1/18), respectivamente. Na C1, observou-se uma predominÃncia de cocos gram-negativos (15/18) e bacilos gram-negativos (14/18), representando 83.3% e 77.8%, respectivamente. Na C2, os Ãnicos morfotipos detectados foram cocos gram-positivos (1/10), presente em 10% das amostras positivas, e na C3, os cocos-gram positivos predominaram (66.7%). Pode-se concluir que o preparo quÃmico-mecÃnico desempenhou sua funÃÃo antibacteriana ao reduzir significativamente o nÃmero de microorganismos do canal principal, porÃm o hidrÃxido de cÃlcio possui um efeito antibacteriano limitado, nÃo sendo capaz de prevenir o recrescimento de bactÃrias apÃs seu uso como medicaÃÃo intracanal. / One of the main objectives of endodontic treatment of roots canals with necrotic pulps consists in eliminating the microorganisms spread throughout the ramifications of root canal system. This study, comprised by one manuscript, had the objective to evaluate the antiseptic efficacy of biomechanical preparation and a calcium hydroxide-paste in root canals of human primary teeth with necrotic pulp after trauma and to detect the microorganisms Fusobacterium nucleatum and black-pigmented bacilli in this teeth. According to stringent inclusion criteria, 18 primary teeth with necrotic pulp were selected. Bacterial samples were taken after crown access (S1) and 72h after the removal of dressing with a calcium hydroxide paste (S3), but to 10 teeth were taken a other bacterial sample after chemomechanical preparation with 0.5% NaOCl as an irrigant (S2). Bacteriological samples were collected by introducing 3 sequential sterile absorbent paper points, of a size visually compatible with the root canal diameter. After approximately 1 min, the paper points were removed and placed in a test tube containing reduced transport fluid and were sent for microbiological evaluation. In the S1, the microorganisms were found in 7/18 (94,4%) of the samples, with a colony forming units (CFUâs) media of 5.4 x 105. In the S2, bacteria were cultured in only 1/10 (10%) root canal, with the CFUâs media of 4.3 x 102, and in the S3 bacteria were cultured in 15/18 (83.3%), with the CFUâs media of 1.5 x 105. A statistically significant reduction in bacterial counts was observed between S1 and S2, however no statistically significant difference was observed for comparisons involving S1 and S3, and S2 and S3. The microorganisms Fusobacterium nucleatum and black-pigmented bacilli were detected in 55.5% (10/18) and 11.1% (2/18), respectively, in the S1, no were found in the S2, and in the S3 were found in 16.6% (3/18) and 5.5% (1/18), respectively. In the S1, the gram-negative cocci (15/18) and gram-negative rods (14/18) were the most prevalent groups (83.3% and 77.8%, respectively). In the S2, the gram-positive cocci was the only group of the bacteria observed (1/10), and in the S3, the gram-positive cocci was the group most commonly recovered (66.7%). It was conclude that biomechanical preparation were important in the antisepsis of the root canal because reduced significantly the number of bacteria in the main canal however the calcium hydroxide paste had a antibacterial efficacy limited, no prevent the regrowing bacterial after used as dressing intracanal.

O conceito de PDT é a fotoindução da citotoxicidade das células proliferativas envolvendo um agente fotossensibilizador, uma fonte de luz e oxigênio. Apesar de ser uma terapia eficiente no tratamento de várias neoplasias, a PDT apresenta algumas limitações dentre as quais a não seletividade em células do tecido hepático.O presente trabalho avaliou a correlação entre penetração luminosa e necrose, assim como a extensão da mesma em função da concentração do fotossensibilizador utilizado (Photogem) e de três diferentes doses de energia. A transição do epitélio necrosado e do epitélio sadio, foi realizada após a irradiação de fígados normais de ratos previamente fotossensibilizados. O acúmulo do Photogem, administrado via endovenosa, no fígado, foi investigado através da espectroscopia de fluorescência. As fontes de luz utilizadas para irradiação foram um laser de diodo de 630nm e um dispositivo a base de LEDs (diodos emissores de luz). Observamos que o tecido hepático normal, fotossensibilizado, apresenta suas características ópticas alteradas, evidenciadas nos estudos de penetração da luz e alteração térmica durante a irradiação, refletindo na profundidade da necrose. Verificamos que a presença do FS no tecido alvo diminui a penetração da luz, levando a um aumento da temperatura, devido à grande quantidade de energia absorvida pelo FS, a qual é dissipada na forma de calor. Notamos uma abrupta delineação da necrose correspondendo à queda de intensidade luminosa no tecido iluminado. A profundidade de necrose obtida com o uso do LED apresentou uma pequena variação, devido à linha espectral do mesmo ser mais larga, quando comparado ao laser. Histologicamente o tecido hepático e irradiado apresentou necrose coagulativa, infiltrado inflamatório neutrofílico e necrose da veia centrolobular em todos os grupos experimentais; também observamos uma nítida delimitação entre o tecido epitelial normal e o tecido epitelial fotossensibilizado. Estes resultados serão importantes para o desenvolvimento de estratégias para um possível protocolo para aplicação da PDT em tumores malignos hepáticos. / The PDT concept is the photo induction of the citotoxicity of proliferating cells involving a photosensitizer agent, a light source and oxygen. Despite being an efficient therapy on the treatment of several neoplasias, PDT presents some restrictions including the non-selectivity in hepatic tissue cells. This work evaluated the correlation between light penetration and necrosis, as well as the extension of such as function of the concentration of the photosensitizer used (Photogem) and three different doses of energy. The necrosed epithelium and healthy epithelium transition was performed after the irradiation of normal livers of previously photosensitized rats. The Photogem accumulation, intravenously administrated, on the liver was investigated through fluorescence spectroscopy. The light sources used for irradiation were: diode laser operating at 630 nm and a LEDs (Light Emitting Diode) device. We observe that the photosensitized normal hepatic tissue presents its optical characteristics altered, which was previously evidenced on the studies of light penetration and thermal alteration during the irradiation, altering the necrosis depth. We checked that the photosensitizer presence on the target tissue decreases the light penetration leading to a temperature increase, due to a large amount of energy absorbed by the photosensitizer, which is dissipated by means of heat. We noticed an abrupt necrosis delineation corresponding to the drop of the light intensity on the irradiated tissue. When the LED was used, the necrosis depth presented little variation, due to its spectral line being larger when compared to the laser’s spectral line. Histological, the irradiated hepatic tissue presented coagulative necrosis, inflammatory infiltration neutrophilic and centrilobular vein necrosis in all experimental groups, we also observed a clear delimitation between normal epithelial tissue and photosensitized tissue. These results will be important to the development of strategies for a possible protocol for the PDT application on hepatic malign tumors.

Infectious Pancreatic Necrosis (IPN), due to infection with the IPN virus (IPNv), continues to cause heavy mortalities and is endemic across the major Atlantic salmon farming regions of the world. Prevalances of 0.3-0.8 or more at the freshwater stage and 0.05 to 0.3 in the seawater phase of production are typical. Partially effective injectable vaccines are available against seawater IPN but biosecurity measures remain the main methods of control. To explore the feasibility of selecting salmon for resistance to IPN, a selective breeding program was initiated in 1996, including a series of field and experimental trials challenging known full-sib families with IPNv. A total of 404,723 fish faced IPNv challenge (376,541 seawater and 28,182 freshwater) covering 14 years and 17 separate locations across 7 sites. Mortalities and survivors following IPN challenge were counted by full-sib family and analysed as binomial data (alive / dead). Initial heritabilities were obtained from expressions based on the variance and covariance of full-sib family means for the 2001 year-group, indicating heritabilities (h2) of 0.16, range 0.08 to 0.24, and genetic correlations (rg) between replicate families of 0.71 to 0.78. These results were then confirmed by residual maximum likelihood across all seawater challenged data (year-groups 1997-2003), indicating a h2 of 0.43 (s.e.0.02) across all sites, range 0.06 to 0.40 for individual sites, and a range of rg between replicates of 0.70 to 0.87 (s.e. approx 0.05). To accommodate datasets and pedigrees approaching half a million individually identified fish, an implementation of the Reduced Animal model (RAM) was used to obtain these estimates. A similar level of genetic variation for resistance to freshwater IPN (year-groups 2005-2009) was confirmed with a h2 of 0.49, (s.e. 0.03), range 0.31 to 0.59, and rg between replicates ( 0.80 to 0.95, s.e. approx 0.05), using an Individual Animal Model. When all the data were analysed together, assuming seawater and freshwater survival to be the same trait, the heritability increased to 0.67, (s.e. 0.02). On testing this assumption, the genetic correlation between freshwater and seawater survival was found to be 0.68 s.e. 0.09. Both these pooled estimates account better than those for the individual site estimates, for the known selection of superior families that was incorporated at the earliest opportunity (2001) into the selective breeding program. To further investigate if there were favourable or antagonistic relationships operating between traits under active selection, genetic correlations between IPN mortality and a range of performance and harvest traits were obtained. When restricting the harvest data to year-groups where the harvested fish had not experienced an IPN event (2003 for seawater IPN, 2005 for freshwater IPN) : fish length and flesh colour just reached significance with seawater IPN (0.27 to 0.53. s.e. 0.14), while only harvest weight (0.30 s.e 0.11) attained significance with freshwater IPN mortality. All these correlations were antagonistic. When all the data were combined, (ie both IPN and harvest events taken from all yeargroups) these became non-significant. Taken as a whole, these results indicate that selecting salmon for resistance to both seawater and freshwater IPN challenge certainly is feasible, and that adverse effects on selection for other important production traits is not expected. How these medium to high heritabilities relate to the discovery of a major QTL for IPN resistance segregating in these populations, reported in a parallel scheme of work but based on a sub-set of the same families, is discussed.

A utilização de implantes cirúrgicos para artroplastia de quadril com prótese de recapeamento da cabeça femoral como substituto ósseo é um procedimento que tem sido realizado em 35% dos casos de Osteoartrose nos EUA. Entretanto, o atrito da broca e o aumento da temperatura durante a usinagem da cabeça femoral são responsáveis pelo possível aquecimento do tecido ósseo, podendo provocar a necrose óssea térmica. Neste sentido, o desenvolvimento de novos ferramentais e metodologias para minimizar os danos térmicos do atrito torna-se importante. Diante disso, o presente estudo teve como objetivo verificar se há a ocorrência de necrose óssea em um procedimento de furação óssea utilizando o dispositivo EQUITRON; Mod.ES 2200, desenvolvido no LTC-EESC-USP. Para tal, utilizamos 4 amostras de costela bovina removidas após a morte do animal, que foram furadas com broca de aço inoxidável (HSS-SKF), de 8 milímetros, sem irrigação externa. As amostras foram furadas com rotações de 100, 1000, 1200 e 2500 RPM, aferidas por tacômetro foto/contato digital da marca MINIPA, MDT-2238, e com avanço controlado de 80 mm/min (dispositivo da marca-EQUITRON; MOD.ES 2200; RPM 2800; Potência 0,30; Torque 1,6 Nm). Foram mensuradas as temperaturas iniciais da broca e da amostra e a final da amostra com termômetro digital, marca-MEDISANA®. Após a furação foram confeccionadas lâminas histológicas (HE) do tecido ósseo, preparadas de acordo com a metodologia apropriada, para posterior qualificação e quantificação da ocorrência de necrose óssea térmica através de imagens captadas por microscopia óptica (Olympus BX 41TF - Made Japan) utilizando-se o programa Motic Images Plus 2.0 para a captura das imagens. Os valores de temperaturas aferidos na amostra após a furação apresentaram relação positiva com a RPM utilizada, isto é, quanto maior a rotação, maior foi a temperatura observada. Apenas a amostra furada a 2500 RPM ultrapassou a temperatura de referencia para a gênese da osteonecrose térmica, que é de 47ºC. As análises histológicas apresentaram uma baixa predominância de células picnóticas e lacunas, sugerindo menor dano tecidual. Os resultados obtidos no presente estudo sugerem que o dispositivo (furadeira) desenvolvido no LTC-EESC-USP para a realização das furações nas amostras ósseas em testes de bancada foi eficiente em minimizar a ocorrência de necrose óssea térmica, até mesmo em condições de temperatura acima do limite fisiológico aceitável. / The utilization of surgical implants for hip arthroplasty with a resurfacing prosthesis of the femoral head as a bone substitute have been conducted in 35% of osteoarthrosis cases in the USA. However, the friction of the drill and the increase in the temperature during the machining of the femoral head can possibly heat the bony tissue and provoke a thermal bone necrosis. The development of new tools and methodologies for minimizing the thermal damage of the friction has become fundamental. The present study analyzes the occurrence of bone necrosis in a procedure of bone drilling that uses an EQUITRON device, Mod. ES 2200, developed at the LTC-EESC-USP. Four samples of bovine ribs removed after the death of the animal were used for the tests. They were drilled by an 8mm stainless-steel drill (HSS-SKF) with no external irrigation, at 100, 1000, 1200 and 2500 RPM calibrated by a MINIPA, MDT-2238 digital photo/contact tachometer and whose 80mm/min. advance (EQUITORN device; MOD.ES 2200; RPM 2800; 0.30 Potency and 1,6Nm torque) was controlled. The initial temperatures of the drill and the sample and the final temperature of the sample were measured by a MEDISANA digital thermometer. After drilling, histological blades (HE) were produced from the bony tissue and prepared according to the adequate methodology for further qualification and quantification of the occurrence of thermal bone necrosis through images captured by optical microscopy (Olympus BX 41TF - made in Japan) and Motic Images Plus 2.0 program. The values of the temperatures measured in the sample after drilling showed a positive relation with the RPM utilized, i.e., the faster the rotation, the higher the temperature. Only the sample drilled at 2500RPM exceeded the reference temperature (47ºC) for the genesis of the thermal osteonecrosis. The histological analyses revealed a low predominance of picnotic cells and gaps, which suggest minor tissue damage. The results show the device (drilling machine) developed at the LTC-EESC-USP for the drilling in the bone samples in workbench tests is efficient to minimize the occurrence of thermal bone necrosis, even at temperatures above the physiological acceptable limit.

Ataxia telangiectasia and Rad3-related (ATR) is well known for its regulatory role in DNA damage responses (DDR) as a checkpoint kinase that phosphorylates hundreds of protein substrates. However, its role in cellular non-DNA damage stress responses (NDDR) is unknown. Necrosis is one form of cell death and traditionally has been regarded as a passive and uncontrolled cell death. Recently, evidence has emerged to support the concept that necrosis also may occur in a programmed manner and that PARP1 can be a mediator. Active poly (ADP-ribose) polymerase 1 (PARP1) hydrolyzes nicotinamide adenine dinucleotide (NAD+) to produce poly (ADP-ribose) (PAR) polymers on target proteins or itself. As a result, hyper-activity of PARP1 may lead to necrosis by excessively depleting ATP pool which results in mitochondrial energetic collapse. On the other hand, it is known that Ca2+ overload induces necrosis, but much still remains unknown about how Ca2+ overload-induced necrosis is regulated in cells. In this study, we show that ATR, besides its hallmark regulatory role in DDR, also plays a role in NDDR by suppressing ionomycin-induced necrosis. Ionomycin as a Ca2+ ionophore can dramatically raise the intracellular level of Ca2+, leading to necrosis. We found that this Ca2+ overload-induced necrosis occurs without inducing DDR in cells. Instead, the hyper-poly(ADP-ribosyl)ation (PARylation) activity of activated PARP1 could be a reason leading to necrosis, as NAD+ supplied to media can rescue ionomycin-induced necrosis. In vitro PARylation assay also demonstrates that PARP1 hyper-activation is Ca2+ dependent. In cells, ATR-PARP1 interaction happened after ionomycin treatment. Furthermore, ionomycin treatment induces more full-length PAR polymers formed in ATR-deficient cells than in ATR-proficient cells. The interaction of kinase-dead ATR and PARP1 dramatically decreased as compared to wild-type ATR. Therefore, ATR plays a novel role in NDDR wherein it is able to suppress Ca2+ overload-induced PARP1-mediated necrosis. Ca2+ overload-induced cell death is a major cause of many human medical conditions and diseases, such as brain injury, stroke and ischemia et al. Our ongoing studies will help to define the molecular mechanisms of the anti-necrosis activities of ATR, which may support ATR as a new clinical target for therapeutic treatment of those diseases.