The objective of this study is to test the hypothesis that morphologically different mitochondria-rich (MR) cells may be responsible for the uptake of different ions in freshwater-adapted fish. Tilapia (Oreochromis mossambicus) were acclimated to high-Ca, mid-Ca, low-Ca, and low-NaCl artificial freshwater, respectively, for 2 wk. Cell densities of wavy-convex, shallow-basin, and deep-hole types of gill MR cells as well as whole-body Ca(2+), Na(+), and Cl(-) influxes were measured. Low-Ca fish developed more shallow-basin MR cells in the gills and a higher Ca(2+) influx than those acclimated to other media. However, fish acclimated to low-NaCl artificial freshwater predominantly developed wavy-convex cells, and this was accompanied by the highest Na(+) and Cl(-) influxes. Relative abundance of shallow-basin and wavy-convex MR cells appear to be associated with changes in Ca(2+) and Na(+)/Cl(-) influxes, suggesting that shallow-basin and wavy-convex MR cells are mainly responsible for the uptake of Ca(2+) and Na(+)/Cl(-), respectively.

Head and neck (HN) cancer is an endemic disease in Taiwan, China. Locally recurrent HN cancer after full-dose irradiation poses a therapeutic challenge, and boron neutron capture therapy (BNCT) may be a solution that could provide durable local control with tolerable toxicity. The Tsing-Hua Open Pool Reactor (THOR) at National Tsing-Hua University in Hsin-Chu, provides a high-quality epithermal neutron source for basic and clinical BNCT research. Our first clinical trial, entitled “A phase I/II trial of boron neutron capture therapy for recurrent head and neck cancer at THOR”, was carried out between 2010 and 2013. A total of 17 patients with 23 recurrent HN tumors who had received high-dose photon irradiation were enrolled in the study. The fructose complex of l-boronophenylalanine was used as a boron carrier, and a two-fraction BNCT treatment regimen at 28-day intervals was used for each patient. Toxicity was acceptable, and although the response rate was high (12/17), re-recurrence within or near the radiation site was common. To obtain better local control, another clinical trial entitled “A phase I/II trial of boron neutron capture therapy combined with image-guided intensity-modulated radiotherapy (IG-IMRT) for locally recurrent HN cancer” was initiated in 2014. The first administration of BNCT was performed according to our previous protocol, and IG-IMRT was initiated 28 days after BNCT. As of May 2017, seven patients have been treated with this combination. The treatment-related toxicity was similar to that previously observed with two BNCT applications. Three patients had a complete response, but locoregional recurrence was the major cause of failure despite initially good responses. Future clinical trials combining BNCT with other local or systemic treatments will be carried out for recurrent HN cancer patients at THOR.

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Addition of Mn(II) at 2.5 ,uM or higher to stationary-phase cultures of Deinococcus radiodurans IR was found to trigger at least three rounds of cell division. This Mn(II)-induced cell division (Mn-CD) did not occur when the culture was in the exponential or death phase. The Mn-CD effect produced daughter cells proportionally reduced in size, pigmentation, and radioresistance but proportionally increased in activity and amount of the oxygen toxicity defense enzymes superoxide dismutase and catalase. In addition, the concentration of an Mn-CD-induced protein was found to remain high throughout the entire Mn-CD phase. It was also found that an untreated culture exhibited a growth curve characterized by a very rapid exponentialstationary transition and that cells which had just reached the early stationary phase were synchronous. Our results suggest the presence of an Mn(II)-sensitive mechanism for controlling cell division. The Mn-CD effect appears to be specific to the cation Mn(II) and the radioresistant bacteria, deinococci.Bacteria of the genus Deinococcus, formerly a part of Micrococcus (27), are known for their extremely high radiation resistance (22). These bacteria also have unusual cell wall amino acids (38), polar lipids (10), and surface layers (4). Extensive investigations mainly on radiation-sensitive mutants have attributed the extreme radioresistance to effective DNA repair (13,(22)(23)(24)26). The chemical requirements for optimal growth and for the expression of high radioresistance in deinococci remain largely unknown, partly because of the lack of appropriate chemically defined medium (19, 32). There is limited information on the effects of the divalent cation Mn(II). It has been reported that Deinococcius radioduirans can accumulate manganese in large amounts (18), and Mn(II) was found to be required for the activity of a DNA repair enzyme (14) in this bacterium and was implicated in its high radioresistance (37

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