Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [111]-128).

A phylogenetic study of eleven cetaceans was undertaken using Restriction Endonuclease Maps (RSM) of mitochondrial DNA (mtDNA). One species from the suborder mysticeti (baleen whales) was sampled, and of the ten odontocetes (toothed whales) sampled two were from the family Ziphiidae (beaked whales) and eight were from the family Delphinidae (dolphins) (each representing a different genus). The primarily opportunistically obtained (i.e. from strandings or accidental death in commercial trawl nets) heart tissue generally yielded high quantities of mtDNA which is needed for double digest fragment analysis. The mtDNA extracted from the sampled taxa was cleaved with fifteen different six-base Restriction Enzymes (RE's). Using the three-way method of analysis and aided by the computer program Resolve (Ver. 2.7) (Harley, unpublished), RSM's were constructed. Distance (Neighbor-Joining and Fitsch-Margoliash) and cladistic (Maximum Parsimony and Bootstrap) methods were used to infer phylogenies. The baleen whale was used as an outgroup for the cladistic analysis. Both the distance and both the cladistic methods produced the same single topology, which is concordant with morphologically based classifications. The two differences (within the Delphinidae), viz. Grampus' most basally rooted position and Cephalorhynchus' grouping with the Delphininae are of taxa whose groupings are unresolved in the morphologically based classifications. Using Brown et al's (1979) molecular clock, very recent divergence times at the generic, family and suborder levels were obtained, when compared to fossil based estimates. Using the odontoceti/mysticeti split the base substitution rate of cetacean mtDNA was estimated to be much slower than that of terrestrial mammals (0,3% compared to 1,0% Myr⁻¹). A similarly slow rate was calculated for cetacean nuclear DNA (nDNA) (0,09% Myr⁻¹) (Schlotterer et al, 1991). It remains an unresolved issue as to whether the base substitution rate of cetacean DNA is slower than terrestrial mammals or whether the fossil evidence needs to be reinterpreted. The time of the mysticeti/odontoceti split is palaeontologically uncertain and the suggested monophyletic status of the extant suborders has been questioned, thus making the calculation of cetacean base substitution rate risky. Equally, the incomplete fossil record can lend itself to misinterpretation.

Two plaque-pure phage lambda clones designated as λhtX-l and λhtX-2 that hybridized to unfractionated bovine liver tRNA were isolated from a human X chromosome-specific library. The λDNAs were characterized by restriction mapping and Southern blot hybridization techniques. The human DNA segment in λhtX-l contains five or more presumptive tRNA genes and at least one Alu family member. The 19-kilobase human DNA insert in λhtX-2 contains two or more presumptive tRNA genes and at least three Alu family members. Another human genomic clone designated λhVKV7 hybridized to mammalian valine tRNA IAC. The clone was characterized by physical mapping and Southern blot hybridization techniques. The 18.5-kilobase human DNA fragment in λhVKV7 contains a cluster of three tRNA genes and at least nine Alu family members.

A radiação ionizante prévia promove alterações actínicas em tecidos peritumorais,o que poderia influenciar a demarcação do linfonodo sentinela.O presente estudo desenvolveu modelo experimental para demarcação do linfonodo sentinela do reto do rato e para definição da dose de radiação (curva de calibração). O objetivo foi avaliar a influência da radiação ionizante pré-operatória sobre a marcação, com corante azul patente, do linfonodo sentinela do reto de ratos. A amostra foi constituída por 40 ratos machos Wistar e dividida em 2 grupos:Grupo 1 (controle não irradiado; n = 20) e Grupo 2 (irradiado com 1200cGy e demarcado 2 dias após; n = 20). Foi observado aumento linear do tempo de coloração do linfonodo no Grupo 2. Concluindo,a irradiação pré-operatória não influiu na demarcação do linfonodo sentinela do reto do rato / Previous ionizing radiation induces actinic alterations in peritumoral tissues and thus might influence the localization of the sentinel lymph node. The present study developed an experimental model for the localization of the sentinel lymph node of the rectum of the rat and for the definition of the dose of radiation (calibration curve). The objective was to evaluate the influence of preoperative ionizing radiation on the staining of a patent blue dye in the sentinel lymph node of the rectum in rats.The sample was composed of 40 male Wistar rats and was divided in two groups: Group 1 (non-irradiated control; n = 20 ) and Group 2(irradiated with 1200cGy and stained 2 days afterwards; n = 20). It was observed a linear increase in the time for the staining of the lymph in Group 2.In conclusion, preoperative irradiation did not influence the staining of the sentinel lymph node of the rectum in rats

A radiação ionizante prévia promove alterações actínicas em tecidos peritumorais,o que poderia influenciar a demarcação do linfonodo sentinela.O presente estudo desenvolveu modelo experimental para demarcação do linfonodo sentinela do reto do rato e para definição da dose de radiação (curva de calibração). O objetivo foi avaliar a influência da radiação ionizante pré-operatória sobre a marcação, com corante azul patente, do linfonodo sentinela do reto de ratos. A amostra foi constituída por 40 ratos machos Wistar e dividida em 2 grupos:Grupo 1 (controle não irradiado; n = 20) e Grupo 2 (irradiado com 1200cGy e demarcado 2 dias após; n = 20). Foi observado aumento linear do tempo de coloração do linfonodo no Grupo 2. Concluindo,a irradiação pré-operatória não influiu na demarcação do linfonodo sentinela do reto do rato / Previous ionizing radiation induces actinic alterations in peritumoral tissues and thus might influence the localization of the sentinel lymph node. The present study developed an experimental model for the localization of the sentinel lymph node of the rectum of the rat and for the definition of the dose of radiation (calibration curve). The objective was to evaluate the influence of preoperative ionizing radiation on the staining of a patent blue dye in the sentinel lymph node of the rectum in rats.The sample was composed of 40 male Wistar rats and was divided in two groups: Group 1 (non-irradiated control; n = 20 ) and Group 2(irradiated with 1200cGy and stained 2 days afterwards; n = 20). It was observed a linear increase in the time for the staining of the lymph in Group 2.In conclusion, preoperative irradiation did not influence the staining of the sentinel lymph node of the rectum in rats