In Vivo Real-Time Quantum Dots Imaging to Track Transplanted Adipose Stem Cells in Different Inflammatory States of Acute Liver Failure Mice

Stem cell therapy plays an important role in regenerative therapy; however, there is little information on the in vivo dynamics of transplanted stem cells and the influence of the inflammation of affected tissues or organs on these dynamics. In this study, we revealed real-time dynamics of transplanted adipose tissue-derived stem cells (ASCs) and the influence of the inflammatory states on these dynamics in acute liver failure mice. Quantum dots (QDs) labeling did not affect the cytokine profile of ASCs, and intravenously transplanted ASCs labeled with QDs could be detected in real time with high efficiency without laparotomy. Until 30 min after ASC transplantation, no marked differences in the behavior or accumulation of transplanted ASCs in the liver were observed among the three groups with different degrees of liver damage (normal, weak, and strong). However, significant differences in the engraftment rate of transplanted ASCs in the liver were observed among the three groups from 4 h after transplantation. The engraftment rate was inversely correlated with the extent of the liver damage. These data suggested that QDs are useful for in vivo real-time imaging of transplanted cells, and the inflammatory state of tissues or organs may affect the engraftment rate of transplanted cells.

Immunomodulatory Effects of Adipose Tissue-Derived Stem Cells on Concanavalin A-Induced Acute Liver Injury in Mice

Cell therapy with adipose tissue-derived stem cells (ASCs) is expected to be a candidate for the treatment of fulminant hepatic failure (FHF), which is caused by excessive immune responses. In order to evaluate the therapeutic effects of ASCs on FHF, the in vitro and in vivo immunomodulatory effects of ASCs were examined in detail in the mouse model. The in vitro effects of ASCs were examined by assessing their influence on the proliferation of lymphomononuclear cells (LMCs) stimulated with three kinds of mitogens: phorbol 12-myristate 13-acetate (PMA) plus ionomycin, concanavalin A (ConA), and lipopolysaccharide (LPS). The proliferation of LMCs was efficiently suppressed in a dose-dependent manner by ASCs in the cases of PMA plus ionomycin stimulation and ConA stimulation, but not in the case of LPS stimulation. The in vivo effects of transplanted ASCs were examined in the murine FHF model induced by ConA administration. The ALT levels and histological inflammatory changes in the ConA-administered mice were apparently relieved by the transplantation of ASCs. The analysis of mRNA expression patterns in the livers indicated that the expressions of the cytokines such as Il-6, Il-10, Ifn-γ, and Tnf-α, and the cell surface markers such as Cd3γ, Cd4, Cd8α, Cd11b, and Cd11c were downregulated in the ASC-transplanted mice. The immunomodulatory and therapeutic effects of ASCs were confirmed in the mouse model both in vitro and in vivo. These suggest that the cell therapy with ASCs is beneficial for the treatment of FHF.

Novel positively charged nanoparticle labeling for in vivo imaging of adipose tissue-derived stem cells

Stem cell transplantation has been expected to have various applications for regenerative medicine. However, in order to detect and trace the transplanted stem cells in the body, non-invasive and widely clinically available cell imaging technologies are required. In this paper, we focused on magnetic resonance (MR) imaging technology, and investigated whether the trimethylamino dextran-coated magnetic iron oxide nanoparticle -03 (TMADM-03), which was newly developed by our group, could be used for labeling adipose tissue-derived stem cells (ASCs) as a contrast agent. No cytotoxicity was observed in ASCs transduced with less than 100 µg-Fe/mL of TMADM-03 after a one hour transduction time. The transduction efficiency of TMADM-03 into ASCs was about four-fold more efficient than that of the alkali-treated dextran-coated magnetic iron oxide nanoparticle (ATDM), which is a major component of commercially available contrast agents such as ferucarbotran (Resovist), and the level of labeling was maintained for at least two weeks. In addition, the differentiation ability of ASCs labeled with TMADM-03 and their ability to produce cytokines such as hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostaglandin E2 (PGE2), were confirmed to be maintained. The ASCs labeled with TMADM-03 were transplanted into the left kidney capsule of a mouse. The labeled ASCs could be imaged with good contrast using a 1T MR imaging system. These data suggest that TMADM-03 can therefore be utilized as a contrast agent for the MR imaging of stem cells.

Sural nerve grafting for long defects of the femoral nerve after resection of a retroperitoneal tumour

Most injuries to the femoral nerve are iatrogenic in origin and occur during resection of large retroperitoneal tumours. When the defect is considerable a nerve graft is mandatory to avoid tension across the suture line. We describe two cases of iatrogenic femoral nerve injury which recovered well after reconstruction with long sural nerve grafts. The probable reasons for success were that we performed the grafting soon after the injury, the patients were not too old, the nerve repairs were reinforced with fibrin glue and electrical stimulation of the quadriceps was administered to prevent muscle atrophy. Good functional results may be obtained if these conditions are satisfied even if the length of a nerve graft is more than 10 cm.

Submucosal injection, for endoscopic mucosal resection, of photocrosslinkable chitosan hydrogel in DMEM/F12 medium

BACKGROUND AND STUDY AIMS

We studied the ability of a photocrosslinkable chitosan in DMEM/F12 medium to maintain submucosal thickness and to reduce bleeding after mucosal resection. We also investigated the behavior of chitosan hydrogels with regard to wound healing.

METHODS

The gastric submucosal layer of heparinized rats was injected with the photocrosslinkable chitosan in medium (which was then irradiated with ultraviolet light to form a hydrogel), or with sodium hyaluronate, or hypertonic saline, and three investigations were done, using three different sets of rats. The first and second were measurement of the thickness of the layer, and of the amount of bleeding induced by mucosal resection, respectively. Thirdly, the effects of the chitosan hydrogel on wound healing were examined histologically.

RESULTS

Gastric submucosal layers of chitosan hydrogel-treated animals remained significantly thicker than those of other groups for at least 6 h after injection. The total amount of bleeding 20 min after mechanical mucosal resection was 170.0 +/- 20.0 mg, 678.3 +/- 226.3 mg, and 1020.0 +/- 104.1 mg in the chitosan hydrogel, sodium hyaluronate, and hypertonic saline groups, respectively. Histological study revealed that the focus of bleeding was surrounded by chitosan hydrogel and that almost all the hydrogel was biodegraded within 4 weeks. Furthermore, a discernible, but not statistically significant effect of the chitosan hydrogel on wound healing was observed.

CONCLUSIONS

The chitosan hydrogel produced mucosal elevation after submucosal injection with ultraviolet irradiation, and it significantly reduced bleeding after mucosal resection. Our newly developed chitosan hydrogel in medium might be a promising submucosal agent for endoscopic mucosal resection.

Frequent methylation-associated silencing of a candidate tumor-suppressor, CRABP1, in esophageal squamous-cell carcinoma

Epigenetic alterations and the resulting inactivation of tumor suppressor genes often contribute to the development of various cancers. To identify novel candidates that may be silenced by aberrant methylation in esophageal squamous-cell carcinoma (ESCC), we analysed ESCC cell lines by a recently developed method known as bacterial artificial chromosome array-based methylated CpG island amplification (BAMCA), and selected candidates through BAMCA-assisted strategy. In the course of this program, we identified frequent CpG methylation-dependent silencing of the gene encoding cellular retinoic acid binding protein 1 (CRABP1) in our panel of ESCC cell lines. Expression of CRABP1 mRNA was restored in gene-silenced ESCC cells after treatment with 5-aza 2'-deoxycytidine. The DNA methylation status of the CRABP1 CpG island with clear promoter activity correlated inversely with expression of this gene. CpG methylation of CRABP1 was frequently observed in primary ESCC tissues as well. Restoration of CRABP1 expression in ESCC cells lacking the protein reduced cell growth by inducing arrest at G(0)-G(1), whereas knockdown of the gene in cells expressing CRABP1 promoted cell growth. Among 113 primary ESCC tumors, the absence of immunoreactive CRABP1 was significantly associated with de-differentiation of cancer cells and with distant lymph-node metastases in the patients. These results indicate that CRABP1 appears to have a tumor-suppressor function in esophageal epithelium, and its epigenetic silencing may play a pivotal role during esophageal carcinogenesis. Its expression status in biopsies or resected tumors might serve as an index for identifying ESCC patients for whom combined therapeutic modalities would be recommended.

Reduction rate of lymph node metastasis as a significant prognostic factor in esophageal cancer patients treated with neoadjuvant chemoradiation therapy

Tumor regression is used widely as a measure of tumor response following radiation therapy or chemoradiation therapy (CRT). In cases of esophageal cancer, a different pattern of tumor shrinkage is often observed between primary tumors and metastatic lymph nodes (MLNs). Regression of MLNs surrounded by normal tissue may be a more direct measure of the response to CRT than regression of a primary tumor as exfoliative mechanical clearance does not participate in shrinkage of MLNs. In this study we evaluated the significance of the reduction rate (RR) of MLNs as a prognostic factor in esophageal cancer patients treated with neoadjuvant CRT. Forty-two patients with marked MLNs were selected from 93 patients with esophageal carcinoma who had received neoadjuvant CRT. The RRs of the primary tumor and the MLNs were calculated from computed tomography scans. In 20 patients, surgical resection was carried out following CRT. Univariate analysis was used to determine which of the following variables were related to survival: size of the primary tumor and MLNs; RRs of both lesions; degree of lymph node (LN) metastasis; clinical stage; and surgical resection. Multivariate analysis was then performed to assess the prognostic relevance of each variable. The primary tumor was larger than the MLNs in 69% of patients before CRT and in 40% of patients after CRT. In 79% of the patients, the RR of the primary tumor was greater than the RR of the MLNs. The results of the univariate analyses showed that a high RR of the MLNs and surgical resection after CRT were associated with significantly improved survival. The multivariate analysis demonstrated that the RR of MLNs had the strongest influence on survival. The RR of LN metastasis should be evaluated as an important prognostic predictor in patients with marked LN metastasis of esophageal cancer treated with CRT.

Beneficial effects of immediate enteral nutrition after esophageal cancer surgery

This study was conducted to determine the effects of immediate enteral nutrition (EN) on nutritional status, immunological competence, and the suppression of excessive inflammatory responses in patients following esophageal cancer surgery. Twenty-four patients who underwent the same elective operation for thoracic esophageal carcinoma were randomized into an immediate enteral nutrition (IEN) group who received EN from postoperative day (POD) 1 and a parenteral nutrition (PAN) group. Both groups received comparable volumes and calories on the same POD. Laboratory studies were carried out preoperatively and on PODs 1-7. Other nutritional and immunological assessments were repeated on PODs 1 and 7. Plasma concentrations of nitrate and nitrite were also measured. All of the patients in the IEN group tolerated enteral feeding well. There were no significant differences in the results of nutritional assessments, lymphocyte function, or plasma nitrate and nitrite levels between the two groups. The IEN group showed a significantly earlier recovery of the total lymphocyte count. The serum levels of total bilirubin and C-reactive protein were significantly attenuated in the IEN group. These results indicate that immediate EN may have beneficial effects on immunological competence and the suppression of excessive inflammatory responses in patients following esophagectomy. Patients undergoing radical esophageal surgery who are subjected to severe surgical stress might benefit the most from early EN.

Long-term survival after gastric cancer and liver and paraaortic lymph node metastases: report of a case

We report the case of a 46-year-old man in whom successful resection of carcinoma of the stomach with liver and paraaortic lymph node metastases was carried out. The carcinoma was removed completely with combined resection of the lower esophagus, total stomach, distal pancreas, spleen, two metastatic liver nodes, and groups 1 and 2 and abdominal paraaortic lymph nodes. Adjuvant chemotherapy was administered postoperatively. The patient is currently well with a grade 1 performance status and no signs of recurrence 12 years after his operation. This experience suggests that even the presence of metastatic paraaortic lymph nodes and liver metastases is not necessarily a contraindication to surgery when the carcinoma can be resected curatively and safely.

Radial displacement of the medial meniscus in varus osteoarthritis of the knee

The macroscopic and histologic findings for 31 medial menisci and medial tibial plateaus obtained during total knee arthroplasty were examined to clarify the etiology and progression of varus osteoarthritis. Medial menisci were preserved fairly well in cases of severe osteoarthritis in which the medial joint space had already disappeared. The anterior segment was preserved in 26 (84%) menisci and the posterior segment was preserved in 11 (35%). The medial meniscus may have been preserved because of its radial displacement. Exposure of subchondral bone of the medial tibial plateau occurred in all 31 knees. The exposure of subchondral bone was centered in the anterior, middle, and posterior in nine, 10, and 12 medial tibial plateaus, respectively. There was a mechanical inconsistency between the pattern of preservation of the medial menisci and the location of exposure of subchondral bone on the medial tibial plateaus. The inconsistency reflects that the segment of the medial meniscus on which the excessive load was considered to exist was preserved fairly well. The authors' hypothesis for explaining this inconsistency is that radial displacement of the medial meniscus precedes narrowing of the medial joint space during progression of varus osteoarthritis, so that the displaced meniscus is saved from severe degeneration or attrition.

Pedunculated esophageal leiomyosarcoma: a case report

We report a case of esophageal leiomyosarcoma that possibly arose from the muscularis mucosae, thereby showing a particularly unusual appearance. A large polypoid intraluminal lesion in the distal esophagus was found on an endoscopic examination of a 68-year-old man with a 3-month history of dysphagia. Although the histological examination of biopsy specimens clearly revealed leiomyosarcoma, the absence of an exophytic component on computed tomography (CT) scan caused us to suspect that the tumor was carcinosarcoma. The tumor was resected by a subtotal esophagectomy. Microscopic evaluation revealed no involvement in the layer of the muscularis propria and no component of carcinoma. Clinical features of the pedunculated esophageal leiomyosarcoma shown in this case and three additional cases previously reported in the literature are reviewed.

[Myxoid leiomyosarcoma of the esophagus]

A 34-year-old male patient with epigastralgia was found to have an esophageal submucosal tumor based on an endoscopic evaluation 6 years previously. Because an unusual appearance composed of a heterogeneous solid area and a cyst area on the endoscopic ultrasonogram and the increased size of the tumor on esophagograms over the past 3 years were suggestive of a malignant character, an operation was thus indicated. The tumor, which measured 3.5 x 2.5 x 2.0 cm in size, was enucleated using videoassisted thoracic surgery and was diagnosed to be a very rare myxoid leiomyosarcoma with a thorough pathologic examination. To our knowledge, this is only the second case of esophageal myxoid leiomyosarcoma reported in the literature. We thus consider this case, which demonstrated an unique appearance on an endoscopic ultrasonogram, to possibly be beneficial to the overall diagnostic analysis of esophageal submucosal tumors.

Simultaneous resection of gastric carcinoma and splenectomy in a patient with polycythemia vera: report of a case

We report herein the case of a 57-year-old man who underwent resection of gastric carcinoma after being treated for polycythemia vera (PV) for 16 months. He was admitted with gastrointestinal bleeding; barium meal roentogenogram and endoscopic examination subsequently revealed a Borrmann type II carcinoma in the cardia of the stomach with extension into the lower esophagus. Thus, a lower esophagogastrectomy, distal pancreatectomy, splenectomy, and lymph node dissection were performed. Although an insufficiency of the esophagojejunal anastomosis occurred, the patient suffered no hematologic complications in the setting of careful myelosuppressive and antiplatelet coagulation therapy. He is currently doing well 5 years after his operation, with grade 1 performance status and no signs of recurrence or any hematologic complications.

Successful combined resection of carcinoma of the esophagus and adrenal metastasis: report of a case

We report herein the case of a 56-year-old man who underwent successful combined resection of carcinoma of the esophagus and an adrenal metastasis. The patient presented with carcinoma of the thoracic esophagus, and an adrenal tumor was incidentally detected by computed tomography(CT). Complete removal of the carcinoma was accomplished along with a combined resection of the thoracic esophagus and left adrenal gland. Surgery was followed by the administration of anticancer chemotherapeutic agents. He is currently doing well with a grade 1 performance status and no signs of recurrence 22 months after his operation. To our knowledge, no previous report of the successful simultaneous resection of esophageal carcinoma and an adrenal metastasis has been documented in the literature.

Adenoid cystic carcinoma of the esophagus: report of a case and review of the Japanese literature

We report herein the case of a 79-year-old man with adenoid cystic carcinoma (ACC) of the esophagus. The tumor had a polypoid appearance and was covered by thin esophageal mucosa. As the biopsy specimens suggested a diagnosis of poorly differentiated adenocarcinoma, the patient underwent subtotal esophagectomy with reconstruction of the gastric tube via the posterior mediastinum. Histologically, the carcinoma contained basaloid cells, cribriform foci, and a certain amount of eosinophilic hyaline substance. Some of the basaloid cells were stained immunohistochemically for keratin, muscle actin, and S-100 protein, a pattern which was identical to the pattern of immunoreactivity of the myoepithelium. We reviewed 36 other cases of ACC of the esophagus reported in Japan, with special reference to the criteria for histological diagnosis.

PCNA immunostaining combined with AgNOR staining in esophageal squamous cell carcinoma to identify patients with a poor prognosis

Immunostaining of the proliferating cell nuclear antigen (PCNA) provides important information about cell kinetics and is easily performed on routinely obtained formalin-fixed, paraffin-embedded materials. We report herein the results of a retrospective study on PCNA staining in esophageal cancer undertaken to determine its significance. As this study indicated that immunoreactivity was preserved in specimens fixed within 24h, only 31 specimens from surgical patients were available for this investigation. The mean PCNA index of the patients without invasion to the adventitia (35.7 +/- 17.9) was significantly lower than that of those with invasion to the adventitia or neighboring structures (49.7 +/- 14.5), while the PCNA index did not correlate with other clinicopathologic parameters such as histologic type, lymph node metastases, or prognosis. However, when an analysis of PCNA staining was combined with an analysis of argyrophilic nucleolar organizer region (AgNOR) staining, a correlation with prognosis was found. In fact, seven patients with a high PCNA index (> or = 44) and AgNOR count (> or = 6) had a significantly poorer prognosis than the remaining 22 (P = 0.0014), and six of these seven patients died within 2 years. These results indicate that this combined evaluation may be useful for the identification of patients with a poor prognosis among those undergoing surgery for esophageal squamous cell carcinoma.

[Mitomycin-C-sensitive carcinoid tumor of the gallbladder: report of a case]

A case of carcinoid tumor of the gallbladder, which was sensitive to mitomycin-C is reported. A 49-year-old male was admitted to our hospital with a 2-month history of epigastralgia. He underwent right extended lobectomy of the liver, pancreaticoduodenectomy and lymph node dissection. Histology revealed a carcinoid tumor of the gallbladder with invasion of the liver and lymph node metastasis. About 2 months after the operation, right supraclavicular lymph node metastasis was detected and CT scan revealed abdominal paraaortic lymph node metastasis. The patient was given cis-platinum, but the right supraclavicular lymph node metastasis increased in size and number. After administration of mitomycin-C, the paraaortic lymph node metastasis disappeared. Carcinoid tumor obtained from the right supraclavicular lesion was inoculated into BALB/c nude mice, and sensitivity to anticancer drugs was assayed. This carcinoid tumor was sensitive to mitomycin-C but not to cisplatinum, adriamycin, or nimustine.

[A case of resected metastatic adrenal carcinoma from gastric cancer]

A case of a metastatic adrenal carcinoma is presented. A 67-year-old female underwent total gastrectomy for an adenocarcinoma of the stomach before 52 months. A mass was indicated at the left supra-renal region by computed tomography. The mass was successfully resected by an upper abdominal para-aortic lymph node dissection. Histologically, the mass was confirmed as a metastatic adrenal carcinoma with a lymph node metastasis from the gastric cancer. Metastatic adrenal carcinomas and local lymph node dissections for treating metastatic carcinomas are discussed.

[Lipid metabolism after operation for esophageal cancer]

In order to clarify the abnormal lipid metabolism after resection of esophageal cancer, we measured serum cholesterol, HDL cholesterol, triglyceride phospholipid, free fatty acid, lipoprotein and apoprotein in 38 patients with esophageal cancer before and up to 4 weeks after operation. Patients were divided into three groups; group A consisted of 26 patients whose postoperative course was uneventful, group B, 12 patients who suffered from post-operative complications and group C, 15 control patients who underwent gastrectomy for cancer of the stomach. The conclusions were; 1) After operation, remarkable decrease was observed in many lipids and proteins which were synthesized mainly in the liver. This was more prominent in groups A and B than in group C. There was no difference between group A and B up to 2 weeks, however, after that recovery was slow in group B. 2) This decrease in serum lipids and proteins may be explained by the postoperative liver dysfunction which mimics acute hepatitis, and by abnormal increase in their consumption. 3) In group B, preoperative serum cholesterol, HDL cholesterol and albumin had been significantly lower than those in group A, and cholinesterase, apoAI and apoAII had also tended to be lower.

[Esophageal carcinoma with adenoid cystic differentiation--an immunohistochemical study of two cases with special reference to their histological origin]

Two cases of an esophageal carcinoma with an adenoid cystic differentiation are presented. The first was diagnosed histologically as typical adenoid cystic carcinoma, and the other as being a basal cell carcinoma with an adenoid cystic differentiation. We further investigated these tumors and normal esophageal specimens to determine their histological origin by immunohistochemical staining with either polyclonal or monoclonal antibodies to different classes of human keratin. It was found that both tumors were similar in their reactivities with the anti-keratin antibodies to basal cells of the surface squamous epithelia, but not to the cells composing the esophageal glands, suggesting that they were of basal cell origin.

The hypertrophic uncinate process of the pancreas wrapping the superior mesenteric vein and artery--a case report

The hypertrophic uncinate process of the pancreas wrapping the superior mesenteric vein and artery was discovered during surgery on a patient with nodular chronic pancreatitis. Such a rare anomaly has never been noted in the English literature so far as we have been able to find. This malformation of the pancreatic uncinate process was considered to be due to excess fusion between the ventral and dorsal pancreatic anlages during embryonic stage.

[Systemic hyperdynamic circulation and serum hormone concentrations in portal hypertension]

In order to evaluate the pathogenesis of the systemic hyperdynamic circulation in portal hypertension, serum concentration of eight kinds of hormones including glucagon (Glu), aldosterone (Ald), renin (Ren), and epinephrine (Adr), and the hemodynamic parameters were measured in a series of 30 patients, of whom 23 were patients with liver cirrhosis, 3 were with Banti's disease, 2 with chronic active hepatitis, and 2 with pre-cirrhotic change. The average cardiac index was 4.6l/min, m2, with normal PCWP of 6.7 mmHg. CI. and SVR. showed significant inverse correlation of r = -0.767 (p less than 0.01), however, PCWP and CI did not have any significant correlation. Average serum concentrations of Glu, Ald, and Ren were 160 pg/ml, 139 pg/ml, and 5.4 ng/ml, respectively, all of which were increased up to 2.5 times above the normal values. Adr, norepinephrine, cortisol, estrone and estradiol were within normal limits. Of the eight hormones being measured, only Glu had significant correlation with both liver function tests and the cardiac index (r = 0.479, p less than 0.05). Neither Ald nor Adr had significant correlation with hemodynamic parameters.

[Adenocarcinoma of the esophagus (early stage) concomitant with lung cancer--a case report]

A case of early esophageal cancer, 2.5 cm in length, located just above the esophagogastric junction is presented. This cancer seemed to originate from the fundic gland of the esophagus, because it consisted of the submucosal invasion of well-differentiated adenocarcinoma which was almost completely covered with the squamous cell mucosa of the esophagus. This patient was referred to our clinic because of lower to be a small-cell carcinoma of the lung extending to the mediastinum. He died of the lung cancer one year after operation.

[Establishment of cytotoxic lymphocytes against autologous cholangiocarcinoma from the patient's blood lymphocytes cultured in T cell growth factor (TCGF)]

Experimental studies were performed in order to establish autologous adoptive immunotherapy against human solid tumor. When peripheral blood lymphocytes (PBL) from a patient with cholangiocarcinoma (Ch-1) were cultured in the medium supplemented with T cell growth factor for two weeks they proliferated markedly, and more than 100-fold increase in cell number was achieved. These two week-cultured lymphoid cells (CLC2w) were revealed to consist mostly of cytotoxic T cells and, in a portion, of NK cells, from the examination of markers such as SRBC-rosette formation, peroxidase, surface Ig, IgG Fc receptors, C3 receptors, OKT3 antigen, OKT8 antigen, and so on. In in vitro 51Cr-release cytotoxicity assay, fresh PBL from the patient with Ch-1 showed no cytotoxicity against autologous Ch-1 cells which had been maintained by serial transplantations to BALB/c nude mice, whereas CLC2w exerted obvious cytotoxicity against the autologous Ch-1 cells. CLC2w, however, did not lyse PHA-stimulated autologous lymphoblasts. CLC2w also prevented growth of the autologous tumor in nude mice. NK cell activity of CLC2w appeared to be increased as compared with that of fresh PBL from the patient.

[Immunological competence of nude mice on the growth of transplantable human tumors--with reference to natural killer cells]

Influences of natural killer cells on the transplantable human tumors was evaluated by using anti-asialo GM1 antibody. Two human gastric adenocarcinomas designated as St-4 (poorly differentiated) and St-40 (well differentiated) were inoculated into nude mice. The effects of anti-asialo GM1 antibody were assessed in terms of tumor doubling time (Td) and 3H-thymidine (3H-TdR) uptake labeling index (L.I.). Whereas the Td of St-4 was significantly shortened by administration of anti-asialo GM1 antibody, no noticeable changes were observed in St-40. This enhanced growth of St-4 was also supported by the elevation of L.I. both in flashing and repeating methods. On the other hand, as the repeated L.I. of St-40 was almost 100% in control tumors, repeated L.I. was not increased by the administration of anti-asialo GM1 antibody. It was supported that natural killer activity of nude mice regulated the growth of transplantable human tumors concerning with the growth fractions.