Biomedical subjects
Publications and source records attributed to T Ohtani.
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We have developed a procedure for partially relaxing the barley metaphase chromosomes and exposing fibrous structures from the chromosomes. The observation by atomic force microscopy (AFM) showed that the fibrous structures are typically 0.5 to 1 microm long and 40 to 50 nm in diameter. In higher magnification imaging, we found the fibrous structures were composed of aligned granules and looked like "knobby fiber." These observations are consistent with previously reported features of chromatin fiber observed by AFM and scanning electron microscopy, suggesting that the structures correspond to 30 nm chromatin fibers. We observed the chromatin fiber extending straight from the periphery of the chromosomes in most cases, but fibers with different shapes, such as loop and spiral, were also observed. The procedure reported here will provide a new approach for observing the organization of chromatin fiber to higher-order structures by AFM and other high-resolution microscopy.
Controversies exist regarding the application of the pylorus-preserving pancreatoduodenectomy (PPPD) to malignancies. This study was intended to disclose the pattern of spread of ampullary cancer and to substantiate that tumor spread at resectable stages does not involve the tissues preserved by PPPD. We examined 40 consecutive Whipple pancreatoduodenectomy specimens: mucosal cancer, 4 cases; cancer invading (but not penetrating) the sphincter of Oddi, 1; cancer invading the submucosa of the duodenum, 12; cancer invading the proper muscle of the duodenum, 5; cancer invading the subserosal layer of the duodenum, 7; and cancer invading pancreatic parenchyma, 11. Five cases of mucosal cancer or cancer invading (but not penetrating) the sphincter spread locally without nodal involvement and showed a 5-year survival of 80% without recurrence, being better (p < 0.05) than the 40% survival for patients with more advanced cancers. Sixty-three percent of the remaining 35 cases had metastasis to regional lymph nodes. The 5-year survival of 28% among those with cancer penetrating the proper muscle was worse (p < 0.05) than the 59% survival for those with less advanced cancers. No cases had involved the anatomic structures that would have been preserved by a PPPD. In three cases (7.5%), gastric cancer coexisted. In conclusion, ampullary cancer not penetrating the sphincter spreads locally. Once penetrating the sphincter, it often spreads regionally and causes recurrence. Cancer penetrating the proper muscle of the duodenum bears a worse prognosis. PPPD is an attractive alternative to the Whipple operation for ampullary cancer because no involvement was found in the tissue preserved by the PPPD. However, surgeons should be aware of a concomitant gastric cancer when doing a PPPD.
BACKGROUND: To assess the accuracy of computed tomographic (CT) imaging in the detection of spread and staging of gallbladder carcinoma. METHODS: CT findings of spread of gallbladder carcinoma in 59 Japanese patients who underwent radical surgery were correlated retrospectively with pathologic findings. RESULTS: The incidence of histologically proven nodal involvement was 54% (32 patients) and the most common spread of gallbladder carcinoma. The sensitivities in CT detection of N1 and N2 nodal involvement were 36% and 47%, respectively; positive predictive values were 94% and 92%, respectively. Direct extension to the liver, extrahepatic bile duct, and gastrointestinal tract or pancreas were histologically confirmed in 24, 18, and five patients. The sensitivities in the CT detection of direct spread to the liver of less than 2 cm, more than 2 cm, the extrahepatic bile duct, and the gastrointestinal tract or pancreas were 65%, 100%, 50%, and 57%, respectively; positive predictive values were 77%, 100%, 90%, and 100%, respectively. The incidence of liver metastases and involvement of interaortocaval nodes were 7% and 16%, respectively. The sensitivities in CT detection of liver metastases and involvement of interaortocaval nodes were 75% and 21%, respectively; positive predictive values were 100% and 86%, respectively. CT could not detect direct spread to omentum and peritoneal seedings. CONCLUSION: For detecting the spread of gallbladder carcinoma, CT imaging has low to moderate sensitivity; however, CT imaging can help in determining resectability and in planning the treatment, especially in advanced-stage gallbladder carcinoma, because of a high positive predictive value.
A typical example of rational system synthesis for bioproduction by the cultivation of microorganisms harboring a recombinant plasmid was studied. First, two temperature-controllable expression systems for a foreign gene in Saccharomyces cerevisiae were constructed. The promoter of the PHO84 gene, which encodes an inorganic phosphate (Pi) transporter of S. cerevisiae and is controlled by Pi concentration through the PHO regulatory system, was used. And two temperature-sensitive mutants of S. cerevisiae for the PHO regulatory system were used as the host with rice alpha-amylase expression vector. One was temperature-sensitive pho81 mutant, SH3337, and the other was temperature-sensitive pho80 mutant, YKU107. When the strain SH3337 is cultivated at a lower temperature, the rice alpha-amylase gene connected downstream of the PHO84 promoter is expressed, but at a higher temperature, it is not. Conversely, with the strain YKU107, the transcription of the rice alpha-amylase gene is induced at a higher temperature and repressed at a lower one. The optimal cultivation temperature strategies for maximum production of rice alpha-amylase in batch cultures of these two recombinant strains were then determined by the Maximum Principle using the relationships of the specific growth and specific production rates to the cultivation temperature. The optimal strategies were easy to realize and were shown to be effective for maximum product. Finally, under these maximum alpha-amylase production strategies, the alpha-amylase activities and alpha-amylase yields in terms of glucose consumption for these recombinant strains were calculated on the basis of experimental data and compared for various operation times. The study demonstrates how a foreign gene expression system can be synthesized using a temperature-sensitive mutant with a given objective and under given constraints.
A 49-year-old carpenter was hit by timber around his upper abdomen 1 hour after breakfast. Immediate computed tomography was taken, followed by emergency laparotomy showing gastric rupture accompanied with hemorrhage from the superior mesenteric vein. Hemostasis and distal partial gastrectomy followed by Billroth-I anastomosis reconstruction was performed. Here, we report the abdominal computed tomography findings from a patient with gastric rupture after blunt trauma. The present case, which is only the second such case reported in English literature, suggested that computed tomography is useful for assessing associated injuries in gastric rupture patients, for detecting intraperitoneal free air which can be missed by X-rays, and for locating the laceration of the rupture.
Although many anticancer drugs have been reported to induce apoptosis in cancer cells, the underlying mechanism remains unclear (1-3). Recent studies have revealed that the caspase family of cysteine proteases have been shown to play an important role in the regulation of several apoptotic processes. Thus, the present study investigated whether apoptosis induced by anticancer drugs is mediated by the activation of caspase cascade. NA cells, a squamous cell carcinoma cell line, were exposed to cisplatin (CDDP) or 5-fluorouracil (5-FU) with or without inhibitors of caspase 1, 3 and 8. Analysis of DNA fragmentation revealed that caspase inhibitors consistently inhibited DNA fragmentation induced by 5-FU. During the early stages of apoptosis, phosphatidylserine (PS) is translocated from the inner side of the plasma membrane to the cell surface. This PS externalization was markedly inhibited by treatment with caspase-8 inhibitor. These findings suggested that 5-FU induced apoptosis was mediated by the activation of a caspase cascade involving caspase 1, 3 and 8.