Kota Okinaga

Intracellular targeting therapy of cisplatin-encapsulated transferrin-polyethylene glycol liposome on peritoneal dissemination of gastric cancer

Peritoneal dissemination in gastric cancer is a common fatal clinical condition with few effective therapies available. We studied the therapeutic effect of a tumor‐targeting drug delivery system that uses cisplatin‐encapsulated and Tf‐conjugated PEG liposomes (Tf‐PEG liposomes) in nude mice with peritoneal dissemination of human gastric cancer cells. Small unilamellar Tf‐PEG, PEG or DSPC/CH liposomes (bare liposomes) encapsulating cisplatin were prepared by reverse‐phase evaporation followed by extrusion. Electron microscopic studies revealed that Tf‐PEG liposomes were internalized into tumor cells by receptor‐mediated endocytosis. To examine the biodistribution of each liposome and cisplatin level, nude mice were inoculated i.p. with 107 MKN45P human gastric tumor cells. On the fourth day after tumor inoculation, 3H‐CHE‐labeled and cisplatin‐encapsulated Tf‐PEG, PEG or bare liposome were inoculated i.p. The Tf‐PEG liposome–administered group maintained high liposome and cisplatin levels in ascites and showed a prolonged residence time in the peripheral circulation. Uptake of Tf‐PEG liposomes into the liver and spleen was significantly lower than that of bare liposomes. Uptake of Tf‐PEG liposomes in disseminated tumor cells of ascites and the greater omentum was significantly higher than that of PEG or bare liposomes and a significant increase in cisplatin levels was observed in these tumor cells. Mice receiving Tf‐PEG liposomes 1 and 4 days after the day of tumor inoculation showed significantly higher survival rates compared with those receiving PEG liposomes without Tf, bare liposomes or free cisplatin solution. These results suggest that cisplatin‐encapsulated Tf‐PEG liposomes may be useful as a new intracellular targeting carrier for treatment of gastric cancer with peritoneal dissemination.

Clinicopathologic features of the flat adenoma.

One hundred twenty-eight small flat adenomas (SFAs) were collected from 101 patients, and the clinicopathologic features were investigated. There were 91 adenomas with mild atypia, 20 with moderate atypia, and 17 with severe atypia. SFAs were found more often in males than in females, with a ratio of 3.4∶1, and the malignancy rate in females (31.8 percent) was higher than in males (9.3 percent). About 38 percent of the patients had a history of colorectal carcinoma, and 65 percent had a history of colorectal neoplasms. Of 37 patients whose family history was traced, 21 had cancer families. SFAs were prone to be found in patients with a history of colorectal neoplasms and a cancer family. Malignancy rate increased with increasing size. The overall malignancy rate was 13.3 percent, which was considerably higher than that of ordinary small polypoid adenomas (2.8 percent). SFAs were situated more proximally (30.9 percent) than ordinary adenomas; however, there was no relationship between site and malignancy. All the lesions showed tubular adenomas, and there was no villous feature. A central depression was noted in 20 lesions, more frequently in adenomas with higher atypia. All but one adenoma with severe atypia showed a component of lower atypia, supporting the adenoma-carcinoma sequence.

Detection of tumor cells in blood using CD45 magnetic cell separation followed by nested mutant allele-specific amplification of p53 and K-ras genes in patients with colorectal cancer.

A new method for detecting circulating tumor cells that is based on magnetic‐activated cell separation (MACS) and nested mutant allele‐specific amplification ( nested MASA ) was evaluated in patients with colorectal cancer using the p53 and K‐ras genes as genetic markers. By negative selection with anti‐CD45 monoclonal antibody–conjugated supermagnetic microbeads, the proportion of tumor cells was enriched 9‐fold. By the combination of MACS and nested MASA, 10 tumor cells in 107 normal peripheral blood mononuclear cells could be detected without false‐positives. Using this method, we examined blood taken from the tumor drainage veins of 23 patients with colorectal cancer. Eighty‐seven percent (20/23) of primary tumor tissues showed p53 and/or K‐ras gene mutations. Forty‐five percent (9/20) of patients with p53 and/or K‐ras mutations in the primary tumor showed the same mutated genes in the blood samples. There was a significant association between the presence of p53 and K‐ras gene mutation in the blood and tumor size, depth of invasion, and venous invasion. Blood gene mutation was detected in 80% (4/5) of samples from patients with synchronous liver metastases. Sixty percent (3/5) of patients with mutant genes in the blood developed asynchronous liver metastases after surgery. The overall survival of patients with p53 and/or K‐ras gene mutation‐positive findings in blood was significantly shorter than that of patients testing negative on Kaplan‐Meier analysis. Our results suggest that the method may be useful for reliable detection of tumor cells circulating in the blood and may help to identify patients at high risk for relapse. Int. J. Cancer 89:337–344, 2000.

Role of Pili in the Pathogenesis of Pseudomonas aeruginosa Burn Infection

The present study using three isogenic mutants (F+P−, F−P+, F−P−) of Pseudomonas aeruginosa indicates that the presence of pili enhances the virulence of the organisms in experimental P. aeruginosa burn infection of mice. The 50% lethal dose (LD50) value for burned mice inoculated with non‐piliated (P−) mutant was at least ten times higher than those inoculated with piliated (P+) bacteria. Meanwhile the LD50 value for burned mice inoculated with non‐flagellated (F−) mutant was at least 105 times higher than those inoculated with flagellated (F+) bacteria. At 24 hr after inoculation, the bacterial counts in burned skin of mice inoculated with P+ bacteria were ten times higher than those inoculated with P− bacteria; and at 48 hr the bacterial counts became a hundred times higher in the former mice than the latter. At 24 hr after inoculation, P+ bacteria were isolated from blood, liver (F+P+), lung (F+P+), and kidney, while P− bacteria were not present in these tissues. And at 48 hr after inoculation, P+ bacteria were isolated from all tissues, while P− bacteria were isolated from some sites only. These results suggested that pili and flagella each play an important role as virulence factors independently, and that pili‐mediated enhancement of virulence of P. aeruginosa was attributed to pili‐mediated enhanced colonization of the organisms at the burned skin surfaces.

Optimal site and amount of splenic tissue for autotransplantation

Clinical and basic studies have documented a high susceptibility to pneumococcal infection in asplenic humans and animals. It has been suggested that autotransplantation of splenic tissue might be a method of providing host resistance when total splenectomy is necessary. However, the effect of splenic autograft has remained controversial. This study was performed to evaluate the most effective site and amount of splenic autograft using rats. Rats were divided into five groups for the purpose of determining the site of splenic autotransplantation: splenectomy, sham operation, implantation into the omental pouch, intraperitoneal implantation, and intramuscular implantation. For determining the amount for autotransplantation, the rats were divided into seven groups: splenectomy, sham operation, and implantations of 25, 50, 100, 200, or 300 mg of splenic tissue. All animals were challenged with Streptococcus pneumoniae type 6, 16 weeks after surgery. Howell-Jolly bodies appeared postsplenectomy, but disappeared in the implanted rats 16 weeks after the operation. Histologically, the implanted tissue was indistinguishable from that of a normal spleen. Pneumococcal clearance from the bloodstream and survival rate were significantly higher in rats implanted in the omental pouch as compared with splenectomized rats. Intraperitoneal and intramuscular implanted rats did not show a significant difference from the splenectomized rats. More than 50% of splenic tissue for autograft showed a significant increase in pneumococcal clearance and survival rate as compared with that of splenectomized rats. It was suggested that the most effective site of autotransplantation is the omental pouch and approximately 50% of the whole spleen would be necessary for prevention from sepsis.

Superior Protective and Therapeutic Effects of IL-12 and IL-18 Gene-Transduced Dendritic Neuroblastoma Fusion Cells on Liver Metastasis of Murine Neuroblastoma

Fusion vaccine of dendritic cells (DCs) and tumor cells has the advantage of inducing an immune response against multiple tumor Ags, including unknown tumor Ags. Using the liver metastasis model of C1300 neuroblastoma cells, we assessed the protective and therapeutic effects of fusion cells transduced with the IL-12 gene and/or the IL-18 gene. Improving the fusion method by combining polyethylene glycol and electroporation increased loading efficiency. In the A/J mice vaccinated with fusion cells modified with the LacZ gene (fusion/LacZ), IFN-γ production and CTL activity increased significantly compared with that of DCs/LacZ, C1300/LacZ, or a mixture of the two (mixture/LacZ). With the transduction of IL-12 and IL-18 genes into the fusion cells (fusion/IL-12/IL-18), the level of IFN-γ increased more than five times that of other fusion groups. In addition, NK cell activity and CTL activity increased significantly compared with that of mixture/LacZ, fusion/LacZ, DC/LacZ, or C1300/LacZ. In the protective and therapeutic studies of fusion cell vaccine, mice vaccinated with fusion/LacZ, fusion/IL-12, fusion/IL-18, or fusion/IL-12/IL-18 showed a significant decrease in liver metastasis and a significant increase in survival compared with mice given a mixture/LacZ, DCs/LacZ, or C1300/LacZ. In particular, the mice receiving fusion/IL-12/IL-18 vaccine showed a complete protective effect and the highest therapeutic effects. The present study investigates the improved loading efficiency of fusion cells and suggests that the introduction of IL-12 and IL-18 genes can induce extremely strong protective and therapeutic effects on liver metastasis of neuroblastoma.

Prospective randomized study of two laparotomy incisions for gastrectomy: midline incision versus transverse incision

BackgroundWe performed a randomized study to evaluate the differences between upper midline incision and transverse incision for gastrectomy.MethodsPatients undergoing distal gastrectomy or total gastrectomy for gastric cancer were randomly allocated to have either an upper midline incision or a transverse incision. The times taken to open and close the abdominal cavity, the number of doses of postoperative analgesics, and the incidence of postoperative pneumonia, wound infection, and intestinal obstruction were compared between the patients having the two incisions.ResultsTimes for both opening and closing the abdominal cavity were longer with a transverse incision, in both the distal gastrectomy group and total gastrectomy group. In the patients in whom continuous epidural analgesia was used postoperatively, the number of additional doses of analgesics was smaller in the transverse-incision group after distal gastrectomy. The incidence of postoperative pneumonia was lower in the transverse-incision group after distal gastrectomy. The number of patients with postoperative intestinal obstruction was smaller in the transverse-incision group than in the midline-incision group after distal gastrectomy. In contrast to distal gastrectomy, there was no significant difference in the number of doses of postoperative analgesics, incidence of postoperative pneumonia, or incidence of postoperative intestinal obstruction between the two study groups after total gastrectomy.ConclusionA transverse incision for distal gastrectomy may be more beneficial than an upper midline incision in attenuating postoperative wound pain, decreasing the incidence of postoperative pneumonia, and preventing postoperative intestinal obstruction.

Differentiation of Femoral Versus Inguinal Hernia: CT Findings

OBJECTIVE The purpose of our study was to investigate the CT findings of femoral hernias, focusing on their differentiation from inguinal hernias. MATERIALS AND METHODS We reviewed the records of 46 femoral hernias in seven centers (review of femoral hernias) and those of 215 groin hernias (femoral hernias, 11; inguinal hernias, 204) in one center (review of groin hernias). We evaluated the presence of hernia, extent of hernia sac based on the relationship between the hernia sac and the pubic tubercle (localized sac: sac was localized lateral to the pubic tubercle; or extended sac: sac extended medial to the pubic tubercle), and compression of the femoral vein on CT images. The chi-square test was used to assess the relationship between the CT findings and femoral versus inguinal hernias in the review of groin hernias. RESULTS In the review of 46 femoral hernias, the lesions were detected on CT in 45. In the 45 lesions, all hernia sacs were localized, and 42 lesions showed venous compression. In the review of 215 groin hernias, all 11 femoral hernias had localized sacs with venous compression on CT. Of the 204 inguinal hernias, 98 lesions were detected on CT, 65 had extended sacs, and only 10 showed venous compression. Localized sacs with venous compression were seen much more often in the femoral hernias (11/11, 100%) than in the inguinal hernias (1/92, 1.1%) (p < 0.0001). CONCLUSION CT images are useful to differentiate femoral hernias from inguinal hernias.

The effect of partial splenectomy on experimental pneumonoccal bacteremia in an animal model

The effect of total and partial splenectomy on the blood stream clearance of type 23B Streptococcus pneumoniae was studied in chinchillas 2 wk and 2 mo following surgery to determine the amount of splenic tissue necessary for protection against overwhelming sepsis. Significantly more pneumococci were found in the blood of totally splenectomized chinchillas than in the blood of sham-operated animals throughout the 6-hr sampling period after intravenous inoculation of pneumococci. Animals that had two-thirds of their spleen removed demonstrated a significant delay in clearance of pneumococci compared with sham-operated and hemisplenectomized animals. The rate of pneumococcal clearance was similar for the sham-operated and the hemisplenectomized group, and was significantly prolonged but similar among totally splenectomized and two-thirds splenectomized animals. Pneumococcal opsonic activity was reduced only in the sera of totally splenectomized chinchillas 2 mo after surgery. There was no positive relationship between pneumococcal clearance and change in pneumococcal opsonic activity. These results suggest that the impaired clearance of circulating pneumococci in splenectomized animals is due to the loss of splenic reticuloendothelial cells as a mechanical filter, rather than deficient serum opsonic activity. There appears to be a critical splenic mass required for optimal bacterial clearance, and hemisplenectomy may protect against overwhelming postsplenectomy sepsis.

Flat adenoma of the large bowel

PURPOSE: The aim of this study was to re-evaluate the clinicopathologic features of flat adenomas with special reference to the role of central depression found in flat adenomas. METHODS: Clinicopathologic features, such as grade of atypia by size, site, central depression, coexisting lesions, gender, and family history of cancer, were evaluated in 236 flat adenomas from 183 patients selected retro-spectively and prospectively. RESULTS: Of the 236 flat adenomas, 175 had mild, 33 had moderate, and 28 had severe (i.e., intramucosal carcinoma) atypia. The frequency of severe atypia correlated positively with size. Severe atypia were significantly more frequent in females (21 percent in females and 10 percent in males;P<0.05). Sixteen percent of flat adenomas in patients with coexisting cancer showed severe atypia, which was significantly more than those without coexisting cancer (P<0.05). The frequency of multiple flat adenomas in patients with two or more family members with cancer was 53 percent, which was significantly higher than in patients with one or no family members with cancer (P<0.05). Central depression was observed in 19 percent of flat adenomas. The rate of severe atypia (22 percent) of flat adenomas with central depression was significantly higher than that (9 percent) of flat adenoma without central depression (P<0.05). Patients who had flat adenomas with central depression had a higher incidence of coexisting cancer and cancer in the family (P<0.05 andP<0.01). CONCLUSION: At colonoscopic examination consideration should be given for the increased potential to become malignant in flat adenomas, especially those with central depression and in patients with a history of malignancy or with a family history of malignancy.