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J Koh

Publications and source records attributed to J Koh.

89 records · Page 5Linked to original sources
PubMed1986

[Application of NMR-CT in the staging of cancer of the digestive organs].

To assess the potential of NMR-CT for demonstrating cancer of the digestive organs, we examined a total of 232 patients (89 with esophageal cancer, 52 with liver cancer, 40 with colorectal cancer, 9 with pancreatic cancer, 9 with gastric cancer, and 33 with other diseases). NMR-CT has many features, but we use especially those features which it is possible to select not only in the transverse plane but also in the coronal and sagittal planes, and it has excellent soft tissue contrast resolution. Our machine is a Picker International NMR-CT using a superconducting magnet of 0.256 tesla. Diagnosis of lymph node involvement of esophageal cancer. Using only the coronal plane, each patient was scanned by the spin echo technique (TE = 40, TR = 400) from the plane of the descending aorta to the plane of the trachea 1 cm in thickness, at 1 cm intervals, continuously. All the vessels were clearly differentiated as no-signal regions, especially in coronal images, from areas of carcinomatous involvement. Lymph nodes were identified as intense grey masses in fat tissue of high intensity. Twenty cases were proved by surgery or autopsy, and it was possible to assess 160 lymph-node groups. A total of 25 patients were imaged as having positive lymph nodes, but 17 of them had metastasis-positive nodes. In other 135 nodes imaged as negative lymph nodes, only two had metastasis and 133 were negative for metastasis. Overall accuracy was 93.8%. Diagnosis of liver cancer. Intrahepatic vessels were clearly imaged without using contrast enhancement in NMR-CT, so it was easy to diagnose the segment containing the tumor and to detect tumor emboli in the portal vein. The capsule was imaged in 84% (16/19) using IR techniques, although only 37% (7/19) could be imaged by X-CT. Diagnosis of colorectal cancer. Using the sagittal plane, the sacrum, urinary bladder and other organs were imaged better parallel to their axis, so that the relationship between rectal cancer and surrounding organs could be clearly visualised with NMR-CT. With regard to lymphatic metastasis, coronal imaging was useful for picturing mesenteric and pelvic vessels, so that lymph nodes were imaged as low-intensity masses along the vessels. Lymph metastasis almost 1 cm size can be detected using coronal NMR-CT.

Digestive System Neoplasms↗
PubMed1985

Central nervous system involvement in congenital visceral fibromatosis.

Congenital visceral myofibromatosis is an uncommon disorder characterized by multiple tumors of myofibroblastic origin in the neonatal period. The natural history of the disorder has been well delineated. The myofibroblast is the cell of origin of the tumor. This is a report of a patient in whom multiple mesenchymal tumors occurred in the CNS as well as in other organs. Light and electron microscopic findings of the CNS lesions are similar to those of the somites and viscera.

Adult↗
PubMed1984

Combined cytotoxic and endocrine therapy for human breast carcinoma (Br-10) serially transplanted into nude mice.

Cytotoxic and endocrine therapy on a human breast carcinoma (Br-10) serially transplanted into nude mice was given with reference to the sequence of drug administration. Mitomycin C (MMC) was combined with 2.5 mg/kg of tamoxifen (TAM). MMC was dissolved in 0.2 ml of physiological saline and administered intraperitoneally once weekly. TAM was dissolved in 0.1 ml of sesame oil and administered intramuscularly twice weekly. Both drugs were administered in the reverse sequence for 2 or 3 weeks. Cytosol estrogen receptor (ERc), nuclear estrogen receptor (ERn) and progesterone receptor (PgR), and 3H-thymidine uptake labeling index (L.I.) were assayed after the treatment. When 1.5 mg/kg of MMC was combined with TAM, statistically significant differences were nil between the different sequential administrations. When the MMC administration was reduced to 0.75 mg/kg and 2 weeks, respectively, the MMC----TAM sequence was more effective than the reversed sequential administration. MMC preserved ERc and depressed L.I. to almost half of that of the control tumor. TAM generated the ER systems and slightly depressed L.I. These different modes of action between MMC and TAM on ER systems and L.I. may explain the antitumor effects of different sequential administrations.

Adult↗
PubMed1984

[Growth of human tumor transplanted into nude mice with various genetic backgrounds].

Nude mice with different genetic backgrounds were used for the experiment to evaluate the growth of human and murine tumors in the different hosts. Twelve human tumors including 5 gastric carcinomas (St-4, St-10, St-15, St-40, KS-1), 2 colon carcinomas (Co-3, Exp-42), 1 breast carcinoma (MX-1), 1 bile duct carcinoma (Ch-1), 1 hepatocellular hepatoma (Li-4) and 2 hemangiosarcomas (LC-27-R, LC-27-UR), and one murine tumor spontaneously arisen from C3H/HeN nu/+ mouse were transplanted into the subcutaneous tissue of nude mice with genetic backgrounds of BALB/cA, DDD and ICR (CD-1). BALB/cA-nu was originated from the Central Institute for Experimental Animals, DDD-nu was supplied from the Institute of Medical Science, University of Tokyo and ICR (CD-1)-nu was supplied from Charles River Co., Ltd. Tumors were measured by the width (W) and length (L) three times a week by the same person. The tumor volume (V) was estimated by the formula V = W2 X L/2. Tumor doubling time (Td) during the exponential growth phase was compared between the nude mice with different genetic backgrounds. It was found that Td of MX-1 in DDD-nu mice and Td of St-40 and Exp-42 in BALB/cA-nu mice were shortened in comparison with those of tumors transplanted into nude mice with the other strains. However, no statistically significant differences were observed when t-test of matched pairs and coefficients of correlation were applied to compare Td in the other kinds of nude mice. Nude mice with genetic backgrounds of DDD and ICR (CD-1) were thought to be also useful for various kinds of therapeutic experiments in human tumor xenografts/nude mice system.

Adenocarcinoma↗
PubMed1983

Human breast carcinoma (MCF-7) serially transplanted into nude mice.

The tumor cells (0.5 ml, 1 X 10(7) of MCF-7 line were inoculated into the subcutaneous tissue or intraperitoneum of female BALB/c nude mice. Primarily transplanted mice were treated with 17 beta-estradiol dipropionate (E2) in a dose of 5 mg/kg and 17 alpha-hydroxy progesterone caproate (Pg) in a dose of 250 mg/kg once a week. After the transferable strain was established, tumors were transplanted into female and male mice treated with E2, Pg, and E2 + Pg. The tumors treated with E2 or E2 + Pg grew exponentially while tumors in the other group regressed. Pg was assumed to play some role in the growth of MCF-7, in the presence of estrogen. Although cytosol estrogen receptors (ERc), nuclear estrogen receptors (ERn), and progesterone receptors (PgR) were detected by dextran coated-charcoal method and exchange assay in the growing tumors, ERn and PgR of regressing tumors was usually negative. This MCF-7 strain in nude mice may be a promising animal model for studying chemo-hormone therapy for human breast carcinomas.

Animals↗
PubMed1983

[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.

Adenocarcinoma↗
PubMed1977

Stress-generated potentials in bone: effects of collagen modifications.

The effect of collagen modification on the magnitude of stress-generated potentials has been studied. A whole bone model has been developed for determining the effects of collagen crosslinking on the electrical signals. Increased crosslinking results in larger electrical signals, and such increases result whether in vivo or in vitro changes in the collagen are made.

Aging↗
PubMedDate not supplied

Lack of point mutation of the APP gene in sporadic Alzheimer's disease in Japanese.

We investigated point mutations of the APP gene in 66 patients with sporadic Alzheimer's disease (AD) and 180 normal individuals by use of the PCR (polymerase chain reaction) method. Both the AD patients and the normal individuals were Japanese. We extracted DNA from blood samples using the phenol-chloroform method and amplified exons 16 and 17 of the APP gene by PCR. PCR products were digested by MBO-II (exon 16) and BCL-1(exon 17). Electrophoresis was carried out with 3% agarose gel and the separated fragments were stained with ethidium bromide. In addition we investigated other point mutations of exons 16 and 17 by use of the PCR-SSCP (single stranded conformation polymorphisms) method, and found no fragments that exhibited point mutations in the AD patients and normal individuals. These findings indicate that the presence of point mutation of the APP gene is not a major cause of AD in the Japanese population.

Aged↗
PubMedDate not supplied

Stability and immunologic activity of immobilized heparinase and bilirubin oxidase.

Two model enzymes, heparinase and bilirubin oxidase, were immobilized via cyanogen bromide, tresyl chloride, epoxide, or carbodiimidazole activated natural and synthetic matrices. The supports released enzymes for 4-20 hr in vitro at 37 degrees C. The most stable linkage was formed by tresyl chloride and oxirane activated supports. No immune response was detected 11 or 21 days after single i.v. injection to New Zealand white rabbits. Acute exposure to the enzyme produced a weak positive response.

Animals↗
PubMedDate not supplied

Human tumors are methionine dependent in vivo.

Methionine-dependence is a tumor-specific biochemical defect expressed by the inability or decreased ability of tumors to grow under the condition of methionine-depletion. Many reports have shown that methionine-dependence occurs in human tumors of all types, including fresh surgical specimens in vitro. However, in vivo determinations of methionine-dependence have thus far been made only in rodent malignant tumors using methionine-deficient diets. We report here for the first time that human cancer xenografts in nude mice are methionine-dependent and when fed a methionine-free diet tumor growth is greatly inhibited. The body weight of mice on the methionine-free diet was found to be maintainable by once-per-week administration of methionine. The data presented here suggest that methionine-dependence can be an important target for human cancer treatment.

Animals↗
PubMedDate not supplied

Stimulation of human tumor xenograft growth by local estrogen biosynthesis in stromal cells.

BACKGROUND: Both biochemical and histochemical studies have demonstrated the expression of aromatase activity in stromal cells surrounding breast cancers, suggesting that local estrogen biosynthesis promotes the growth of these cancers. However, the role of local aromatase activity in stimulating hormone-dependent breast cancer is still controversial. MATERIALS AND METHODS: A hormone-dependent human breast carcinoma xenograft, Br-10 and human fibroblast cells obtained from a patient with benign breast disease were used in the experiments. When subcutaneously inoculated Br-10 started exponential growth in female nude mice, 10(6) fibroblast cells were injected around the tumor with or without intramuscular administration of 50 mg/kg testosterone. RESULTS: The growth of Br-10 treated with fibroblasts and testosterone was significantly enhanced in comparison with the control (p < 0.05). This stimulation by fibroblasts and testosterone was also observed in ovariectomized nude mice. Immunohistochemical staining for aromatase was observed in tumor sections containing Br-10 from mice treated with fibroblasts and testosterone, particularly around the carcinomatous glands. CONCLUSION: We conclude that estrogen produced locally by aromatase in fibroblasts can regulate the growth of hormone-dependent breast carcinoma cells.

Animals↗