Unique treatment policy for well-differentiated thyroid cancer in Japan: results of a questionnaire distributed to members of the Japanese Society of Thyroid Surgery and the International Association of Endocrine Surgeons.
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Although surgery has been the mainstay of treatment for patients with well-differentiated thyroid cancer, the extents of thyroid resection and lymph node dissection adopted in Japan differ from those in other countries. Furthermore, regarding the indications for postoperative radiation therapy and hormonal therapy, and treatment modalities for cancer recurrence, there are marked discrepancies between Japan and other countries. A questionnaire survey was thus conducted among domestic and overseas thyroid surgeons to ascertain the actual treatment policy for well-differentiated thyroid cancer in Japan and various foreign countries. For small papillary carcinomas of 2.0 cm or less (T1), thyroid resection was more extensive in foreign countries than in Japan, although the extent of lymph node dissection was limited in the former. For large papillary carcinomas exceeding 3.0 cm (T2), on the other hand, total thyroidectomy was the treatment of first choice for all overseas respondents, but of only 20% in Japan, despite lymph node dissection being more extensive in Japan than in other countries. Overseas surgeons were much more likely to favor postoperative TSH suppression therapy and high-dose (131)I therapy. For recurrence following surgery for papillary thyroid cancer, both domestic and overseas respondents indicated surgical resection to be the most common treatment option, and favored high-dose (131)I therapy as well. In Japan, however, high-dose (131)I therapy is available only in a few institutions. Such limited indications for high-dose (131)I therapy in Japan may reflect a discrepancy in the frequency of total thyroidectomy, a prerequisite for postoperative high-dose (131)I therapy, between Japan and other countries. This is the first questionnaire study conducted in both Japan and other countries in relation to treatment modalities for thyroid cancer. The results reveal that there is a clear disparity in treatment policies between Japan and foreign countries. (+info)
The role of climate in human mitochondrial DNA evolution: a reappraisal.
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Previous studies have proposed that selection has been involved in the differentiation of human mitochondrial DNA (mtDNA) and climate was the main driving force. This viewpoint, however, gets no support from the subsequent studies and remains controversial thus far. To clarify this issue, a total of 237 complete mtDNA sequences belonging to autochthonous lineages from South Asia, Oceania, and East Asia were collected to seek for the imprint of selection. Based on nonsynonymous (N) and synonymous (S) substitutions analysis, our results confirmed that purifying selection was the predominant force during the evolution of human mtDNA. However, no significant and extensive difference was detected among these three regions, which did not support the climate adaptation hypothesis but preferred random genetic drift to be the main factor in shaping the current landscape of human mtDNA, at least those from Asian and Oceanian regions. (+info)
Melanesian mtDNA complexity.
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Melanesian populations are known for their diversity, but it has been hard to grasp the pattern of the variation or its underlying dynamic. Using 1,223 mitochondrial DNA (mtDNA) sequences from hypervariable regions 1 and 2 (HVR1 and HVR2) from 32 populations, we found the among-group variation is structured by island, island size, and also by language affiliation. The more isolated inland Papuan-speaking groups on the largest islands have the greatest distinctions, while shore dwelling populations are considerably less diverse (at the same time, within-group haplotype diversity is less in the most isolated groups). Persistent differences between shore and inland groups in effective population sizes and marital migration rates probably cause these differences. We also add 16 whole sequences to the Melanesian mtDNA phylogenies. We identify the likely origins of a number of the haplogroups and ancient branches in specific islands, point to some ancient mtDNA connections between Near Oceania and Australia, and show additional Holocene connections between Island Southeast Asia/Taiwan and Island Melanesia with branches of haplogroup E. Coalescence estimates based on synonymous transitions in the coding region suggest an initial settlement and expansion in the region at approximately 30-50,000 years before present (YBP), and a second important expansion from Island Southeast Asia/Taiwan during the interval approximately 3,500-8,000 YBP. However, there are some important variance components in molecular dating that have been overlooked, and the specific nature of ancestral (maternal) Austronesian influence in this region remains unresolved. (+info)
Phylogeny and ancient DNA of Sus provides insights into neolithic expansion in Island Southeast Asia and Oceania.
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Human settlement of Oceania marked the culmination of a global colonization process that began when humans first left Africa at least 90,000 years ago. The precise origins and dispersal routes of the Austronesian peoples and the associated Lapita culture remain contentious, and numerous disparate models of dispersal (based primarily on linguistic, genetic, and archeological data) have been proposed. Here, through the use of mtDNA from 781 modern and ancient Sus specimens, we provide evidence for an early human-mediated translocation of the Sulawesi warty pig (Sus celebensis) to Flores and Timor and two later separate human-mediated dispersals of domestic pig (Sus scrofa) through Island Southeast Asia into Oceania. Of the later dispersal routes, one is unequivocally associated with the Neolithic (Lapita) and later Polynesian migrations and links modern and archeological Javan, Sumatran, Wallacean, and Oceanic pigs with mainland Southeast Asian S. scrofa. Archeological and genetic evidence shows these pigs were certainly introduced to islands east of the Wallace Line, including New Guinea, and that so-called "wild" pigs within this region are most likely feral descendants of domestic pigs introduced by early agriculturalists. The other later pig dispersal links mainland East Asian pigs to western Micronesia, Taiwan, and the Philippines. These results provide important data with which to test current models for human dispersal in the region. (+info)
Molecular evolution of the carboxy terminal region of the zona pellucida 3 glycoprotein in murine rodents.
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In mammals, before fertilization can occur, sperm have to bind to, and penetrate, the zona pellucida (ZP). In the laboratory mouse, which has been used as a model system for fertilization studies, sperm-ZP binding has been found to be mediated by a region at the carboxy terminal, encoded by exon 7 of the Zp3 gene. This region shows considerable interspecific sequence diversity with some evidence of adaptive evolution in mammals, suggesting that it may contribute to species-specific sperm-ZP binding. However, in a previous study of sequence diversity of ZP3 of three species of Australian murine rodents, we found an identical protein sequence of the region encoded by exon 7. Here, we expand this earlier study to determine the sequence diversity of this region in 68 out of the 130 species of Australasian murine rodents. Maximum likelihood analyses, using representatives of both New Guinean and Australian taxa, provide evidence of positive selection at three codons adjacent to, or within, the putative combining-site for sperm of ZP3, but this was not evident when the analysis was restricted to the Australian taxa. The latter group showed low levels of both intra- and inter-generic sequence divergences in the region encoded by exon 7 of Zp3, with little evidence that this region contributes to species specificity of sperm-ZP binding. These findings suggest that the selective forces acting on the Zp3 exon 7 region during the evolution of the Australasian murine rodents have been variable, and that positive selection has only occurred in a few lineages. (+info)
Epidemiology of constipation in Europe and Oceania: a systematic review.
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